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Natural products have been a source of inspiration for chemists and chemical biologists for many years, and have a special relevance in the chemical space. In recent years, several novel synthetic strategies have appeared, such as diversity-oriented synthesis (DOS), biological-oriented synthesis (BiOS), and function-oriented synthesis (FOS), for accessing complex and functionally diverse molecules. In this manner, the synthesis of natural products has evolved towards simpler and ecological methods using biotransformation, combinatorial chemistry, or organocatalysts. In this issue, Prof. Chojnacka shows demonstrates the use of immobilized lipases as catalysts to aid in the synthesis of phosphatidylcholine enriched with myristic acid. Profs. Vila and Pedro used catalysts derived from (S)-mandelic acid to achieve the catalytic enantioselective addition of dimethylzinc to isatins. Prof. Diez shows the possibility of the obtention of 7,8-carvone epoxides in a diastereoselective manner using proline, quinidine, and diphenylprolinol as organocatalysts. A cheap, simple, clean, and scalable method involves the use of deep eutectic mixtures as reaction media, and Profs. Alonso and Guillena describe the use of this methodology for the enantioselective, organocatalyzed ?-amination of 1,3-dicarbonyl compounds. Biotransformations have been one of the methodologies for more efficient synthesis of natural products. Prof. Wu transforms ergostane triterpenoid antcin K using Psychrobacillus sp. Ak 187. Finally, Prof. Kovayashi reviews the total synthesis and biological evaluation of phaeosphaerides. The reader, through this issue, could gain an idea of the new directions that the synthesis of natural products using catalysts will have in the years to come.
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Biomedical Chemistry provides readers with an understanding of how fundamental chemical concepts are used to combat some diseases. The authors explain the interdisciplinary relationship of chemistry with biology, physics, pharmacy and medicine. The results of chemical research can be applied to understand chemical processes in cells and in the body, and new methods for drug transportation. Also, basic chemical ideas and determination of disease etiology are approached by developing techniques to ensure optimum interaction between drugs and human cells. This Book is an excellent resource for students and researchers in health-related fields with frontier topics in medicinal and pharmaceutical chemistry, organic chemistry and biochemistry.
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This book is based on the Special Issue of the journal Molecules on “Smart and Functional Polymers”. The collected research and review articles focus on the synthesis and characterization of advanced functional polymers, polymers with specific structures and performances, current improvements in advanced polymer-based materials for various applications, and the opportunities and challenges in the future. The topics cover the emerging synthesis and characterization technology of smart polymers, core?shell structure polymers, stimuli-responsive polymers, anhydrous electrorheological materials fabricated from conducting polymers, reversible polymerization systems, and biomedical polymers for drug delivery and disease theranostics. In summary, this book provides a comprehensive overview of the latest synthesis approaches, representative structures and performances, and various applications of smart and functional polymers. It will serve as a useful reference for all researchers and readers interested in polymer sciences and technologies.
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Metal–organic frameworks are among the most promising novel materials. The concept of MOFs was first introduced in 1990. They were actually initially used in catalysis, gas separation, membranes, electrochemical sensors. Later on, they were introduced as SPE sorbents for PAHs (Polycyclic Aromatic Hydrocarbons) in environmental water samples, then the range expanded to the field of analytical chemistry, both in chromatographic separation and sample preparation, with great success in, e.g., SPE and SPME (Solid Phase Mico-extraction). Since then, the number of analytical applications implementing MOFs as sorbents in sorptive sample preparation approaches is increasing. ?his is reinforced by the fact that, at least theoretically, an infinite number of structures can be designed and synthesized, thus making tuneability one of the most unique characteristics of MOF materials. Moreover, they have been designed in various shapes, such as columns, fibers, and films, so that they can meet more analytical challenges with improved analytical features.Their exceptional properties attracted the interest of analytical chemists who have taken advantage of the unique structures and properties and have already introduced them in several sample pretreatment techniques, such as solid phase extraction, dispersive SPE, magnetic solid phase extraction, solid phase microextraction, stir bar sorptive extraction, etc.
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Boron-based compounds have been utilized as ligands within transition metal complexes for many decades. The diversity of such compounds in terms of varying functional groups is truly exceptional. Boron compounds are of high interest due to the great potential to modify the substituents around the boron center and to produce a broad range of structural motifs. The many different ways these compounds can coordinate or interact with transition metal centers is astonishing. Examples of transition metal complexes containing boron-based ligands include scorpionates, cluster-type borane- and carboranes, borates, and phosphine-stabilized borylene ligands. This Special Issue brings together a collection of articles focusing on recent developments in the aforementioned boron-based ligands. The articles reported in this book will provide the reader with an overview of the types of boron-based ligands which are currently being researched in groups around the world.
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The subjects of the presented papers cover a wide range of challenges in the area of inorganic fullerene-like nanoparticles and nanotubes. However, it can include only a few comprehensive experimental and theoretical efforts, stepwise evaluating the rationalization of the synthesis, and elucidation of the stability, mechanical, electronic and adhesive properties of these nanostructures. We believe that this thematic issue can be helpful, not only for an advanced researcher to grasp the latest developments in this field, but also to permit a beginner to gain a deeper insight into the field of inorganic fullerene-like nanoparticles and nanotubes.
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This book is a collection of studies focused on the exploitation of enzyme stereoselectivity for the synthesis of relevant chemicals, such as innovative materials, chiral building blocks, natural products, and flavor and fragrance compounds. Different catalytic approaches are reported. The first study describes a resolution-based process for the stereoselective synthesis of the enantiomeric forms of the flavor compound linaloyl oxide, whereas other enantiomeric enriched aroma compounds were obtained through a novel microbial approach based on solid-state fermentation. Two relevant works exploit the potential of the biocatalyzed reduction reactions. The first of these contributions describes the enantioselective synthesis of ?-nitroalcohols by enzyme-mediated reduction of ?-nitroketones, whereas a second contribution reports the preparation of chiral 1,4-diaryl-1,4-diols through ADH-catalyzed bioreduction of the corresponding diketones. Concerning enantioenriched alcohol derivatives, natural hydroxy fatty acids are prepared by means of the biocatalytic hydration reaction of natural fatty acids using the probiotic bacterium Lactobacillus rhamnosus as a whole-cell biocatalyst. Further studies describe the use of modified pullulan polysaccharide for lipase immobilization and the recent advances in synthetic applications of ?-transaminases for the production of chiral amines.
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Electrochemical surface science (EC-SS) is the natural advancement of traditional surface science (where gas–vacuum/solid interfaces are studied) to liquid (solution)/electrified solid interfaces. Such a merging between two different disciplines—i.e., surface science (SS) and electrochemistry—officially advanced ca. three decades ago. The main characteristic of EC-SS versus electrochemistry is the reductionist approach undertaken, inherited from SS and aiming to understand the microscopic processes occurring at electrodes on the atomic level. A few of the exemplary keystone tools of EC-SS include EC-scanning probe microscopies, operando and in situ spectroscopies and electron microscopies, and differential EC mass spectrometry (DEMS). EC-SS indirectly (and often unconsciously) receives a great boost from the requirement for rational design of energy conversion and storage devices for the next generation of energetic landscapes. As a matter of fact, the number of material science groups deeply involved in such a challenging field has tremendously expanded and, within such a panorama, EC and SS investigations are intimately combined in a huge number of papers. The aim of this Special Issue is to offer an open access forum where researchers in the field of electrochemistry, surface science, and materials science could outline the great advances that can be reached by exploiting EC-SS approaches. Papers addressing both the basic science and more applied issues in the field of EC-SS and energy conversion and storage materials have been published in this Special Issue.
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This Issue contains one communication, six articles, and two reviews. The communication from Paola Vitale et al. represents a work where whole cells were used as biocatalysts for the reduction of optically active chloroalkyl arylketones followed by a chemical cyclization to give the desired heterocycles. Among the various whole cells screened (baker’s yeast, Kluyveromyces marxianus CBS 6556, Saccharomyces cerevisiae CBS 7336, Lactobacillus reuteri DSM 20016), baker’s yeast provided the best yields and the highest enantiomeric ratios (95:5) in the bioreduction of the above ketones. In this respect, valuable chiral non-racemic functionalized oxygen-containing heterocycles (e.g., (S)-styrene oxide, (S)-2-phenyloxetane, (S)-2-phenyltetrahydrofuran), amenable to be further elaborated on, can be smoothly and successfully generated from their prochiral precursors. Studies about pure biocatalysts with mechanistical studies, application in different reactions, and new immobilization methods for improving their stability were reported in five different articles. The article by Su-Yan Wang et al. describes the cloning, expression, purification, and characterization of an N-acetylglucosamine 2-epimerase from Pedobacter heparinus (PhGn2E). For this, several N-acylated glucosamine derivatives were chemically synthesized and used to test the substrate specificity of the enzyme. The mechanism of the enzyme was studied by hydrogen/deuterium NMR. The study at the anomeric hydroxyl group and C-2 position of the substrate in the reaction mixture confirmed the epimerization reaction via ring-opening/enolate formation. Site-directed mutagenesis was also used to confirm the proposed mechanism of this interesting enzyme. The article by Forest H. Andrews et al. studies two enzymes, benzoylformate decarboxylase (BFDC) and pyruvate decarboxylase (PDC), which catalyze the non-oxidative decarboxylation of 2-keto acids with different specificity. BFDC from Pseudomonas putida exhibited very limited activity with pyruvate, whereas the PDCs from S. cerevisiae or from Zymomonas mobilis showed virtually no activity with benzoylformate (phenylglyoxylate). After studies using saturation mutagenesis, the BFDC T377L/A460Y variant was obtained, with 10,000-fold increase in pyruvate/benzoylformate. The change was attributed to an improvement in the Km value for pyruvate and a decrease in the kcat value for benzoylformate. The characterization of the new catalyst was performed, providing context for the observed changes in the specificity. The article by Xin Wang et al. compares two types of biocatalysts to produce D-lysine L-lysine in a cascade process catalyzed by two enzymes: racemase from microorganisms that racemize L-lysine to give D,L-lysine and decarboxylase that can be in cells, permeabilized cells, and the isolated enzyme. The comparison between the different forms demonstrated that the isolated enzyme showed the higher decarboxylase activity. Under optimal conditions, 750.7 mmol/L D-lysine was finally obtained from 1710 mmol/L L-lysine after 1 h of racemization reaction and 0.5 h of decarboxylation reaction. D-lysine yield could reach 48.8% with enantiomeric excess (ee) of 99%. In the article by Rivero and Palomo, lipase from Candida rugosa (CRL) was highly stabilized at alkaline pH in the presence of PEG, which permitted its immobilization for the first time by multipoint covalent attachment on different aldehyde-activated matrices. Different covalent immobilized preparation of the enzyme was successfully obtained. The thermal and solvent stability was highly increased by this treatment, and the novel catalysts showed high regioselectivity in the deprotection of per-O-acetylated nucleosides. The article by Robson Carlos Alnoch et al. describes the protocol and use of a new generation of tailor-made bifunctional supports activated with alkyl groups that allow the immobilization of proteins through the most hydrophobic region of the protein surface and aldehyde groups that allows the covalent immobilization of the previously adsorbed proteins. These supports were especially used in the case of lipase immobilization. The immobilization of a new metagenomic lipase (LipC12) yielded a biocatalyst 3.5-fold more active and 5000-fold more stable than the soluble enzyme. The PEGylated immobilized lipase showed high regioselectivity, producing high yields of the C-3 monodeacetylated product at pH 5.0 and 4 °C. Hybrid catalysts composed of an enzyme and metallic complex are also treated in this Special Issue. The article by Christian Herrero et al. describes the development of the Mn(TpCPP)-Xln10A artificial metalloenzyme, obtained by non-covalent insertion of Mn(III)-meso-tetrakis(p-carboxyphenyl)porphyrin [Mn(TpCPP), 1-Mn] into xylanase 10A from Streptomyces lividans (Xln10A). The complex was found able to catalyze the selective photo-induced oxidation of organic substrates in the presence of [RuII(bpy)3]2+ as a photosensitizer and [CoIII(NH3)5Cl]2+ as a sacrificial electron acceptor, using water as oxygen atom source. The two published reviews describe different subjects with interest in the fields of biocatalysis and mix metallic-biocatalysis, respectively. The review by Anika Scholtissek et al. describes the state-of-the-art regarding ene-reductases from the old yellow enzyme family (OYEs) to catalyze the asymmetric hydrogenation of activated alkenes to produce chiral products with industrial interest. The dependence of OYEs on pyridine nucleotide coenzyme can be avoided by using nicotinamide coenzyme mimetics. In the review, three main classes of OYEs are described and characterized. The review by Yajie Wang and Huimin Zhao highlights some of the recent examples in the past three years that combine transition metal catalysis with enzymatic catalysis. With recent advances in protein engineering, catalyst synthesis, artificial metalloenzymes, and supramolecular assembly, there is great potential to develop more sophisticated tandem chemoenzymatic processes for the synthesis of structurally complex chemicals. In conclusion, these nine publications give an overview of the possibilities of different catalysts, both traditional biocatalysts and hybrids with metals or organometallic complexes to be used in different processes—particularly in synthetic reactions—under very mild reaction conditions.
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The Arctic zone of the Earth is a major source of mineral and other natural resources for the future development of science and technology. It contains a large supply of strategic mineral deposits, including rare earths, copper, phosphorus, niobium, platinum-group elements, and other critical metals. The continued melting of the sea ice due to climate change makes these resources more accessible than ever before. However, the mineral exploration in the Arctic has always been a challenge due to the climatic restrictions, remote location, and vulnerability of Arctic ecosystems. This book covers a broad range of topics related to the problem of Arctic mineral resources, including geological, geochemical, and mineralogical aspects of their occurrence and formation; chemical technologies; and environmental and economic problems related to mineral exploration. The contributions can be tentatively classified into four major types: geodynamics and metallogeny, mineralogy and petrology, mineralogy and crystallography, and mining and chemical technologies associated with the exploration of mineral deposits and the use of raw materials for manufacturing new products. The book can be of interest for all those interested in Arctic issues and especially in Arctic mineral resources and associated problems of mineralogy, geology, geochemistry, and technology.
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The characterization of peptides and proteins is central to understanding their function and expression in biological matrices. Moreover, these macromolecules are important biomarkers of many human diseases. In recent years, the performance of separation techniques based on electromigration have significantly increased. The development of microdevices has reduced sample consumption and waste production while high-sensitivity detectors, such as mass spectrometry (MS) or laser-induced fluorescence (LIF), have significantly improved with regards to separation efficiency and detection limits. All of these advancements have led to appreciably enlarged fields of application. Nowadays, a multitude of studies using separation techniques based on electromigration to study proteins and peptides from numerous real matrices are available in the literature. This Special Issue covers the most recent knowledge and advances in the study of peptides and proteins using several electrophoresis techniques, as well as the characterization of relevant proteins and peptides in application areas such as clinical studies, functional foods, and toxicology.
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Palladium (Pd)-based membranes have received a great deal of attention from both academia and industry thanks to their ability to selectively separate hydrogen from gas streams. The integration of such membranes with appropriate catalysts in membrane reactors allows for hydrogen production with CO2 capture that can be applied in smaller bioenergy or combined heat and power (CHP) plants, as well as in large-scale power plants. Pd-based membranes are therefore regarded as a Key Enabling Technology (KET) to facilitate the transition towards a knowledge-based, low-carbon, and resource-efficient economy. This Special Issue of the journal Membranes on “Pd-based Membranes: Overview and Perspectives” contains nine peer-reviewed articles. Topics include manufacturing techniques, understanding of material phenomena, module and reactor design, novel applications, and demonstration efforts and industrial exploitation.
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This book, a collection of 12 original contributions and 4 reviews, provides a selection of the most recent advances in the preparation, characterization, and applications of polymeric nanocomposites comprising nanoparticles. The concept of nanoparticle-reinforced polymers came about three decades ago, following the outstanding discovery of fullerenes and carbon nanotubes. One of the main ideas behind this approach is to improve the matrix mechanical performance. The nanoparticles exhibit higher specific surface area, surface energy, and density compared to microparticles and, hence, lower nanofiller concentrations are needed to attain properties comparable to, or even better than, those obtained by conventional microfiller loadings, which facilitates processing and minimizes the increase in composite weight. The addition of nanoparticles into different polymer matrices opens up an important research area in the field of composite materials. Moreover, many different types of inorganic nanoparticles, such as quantum dots, metal oxides, and ceramic and metallic nanoparticles, have been incorporated into polymers for their application in a wide range of fields, ranging from medicine to photovoltaics, packaging, and structural applications.
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The amide bond represents a privileged motif in chemistry. The recent years have witnessed an explosion of interest in the development of new chemical transformations of amides. These developments cover an impressive range of catalytic N–C bond activation in electrophilic, Lewis acid, radical, and nucleophilic reaction pathways, among other transformations. Equally relevant are structural and theoretical studies that provide the basis for chemoselective manipulation of amidic resonance. This monograph on amide bonds offers a broad survey of recent advances in activation of amides and addresses various approaches in the field.
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Many macro and micro species, from terrestrial and aquatic environments, produce structurally unique compounds and, in many countries, still are the primary sources of medicines. In fact, secondary metabolites are an important source of chemotherapeutic agents but are also lead compounds for synthetic modification and the optimization of biological activity. Therefore, the exploitation of secondary metabolites, or their inspired synthetic compounds, offers excellent opportunities for the pharmaceutical industry. This Medicines Special Issue focuses on the great potential of secondary metabolites for therapeutic application. The Special Issue contains 16 articles reporting relevant experimental results, and an overview of bioactive secondary metabolites, their biological effects, and new methodologies that improve and accelerate the process of obtained lead compounds with regard to new drug development. We would like to thank all 83 authors, from all over the world, for their valuable contributions to this Special Issue.
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Positron emission tomography (PET) and single-photon emission computed tomography (SPECT) are in vivo molecular imaging techniques which are widely used in nuclear medicine for the diagnosis and treatment follow-up of many major diseases. They use biomolecules as probes, which are labeled with radionuclides of short half-lives, synthesized prior to the imaging studies. These probes are called radiopharmaceuticals. Their design and development require a rather interdisciplinary process involving many different disciplines of natural and health sciences. In addition to their diagnostic and therapeutic purposes in the field of nuclear medicine, radiopharmaceuticals provide powerful tools for in vivo pharmacology during the process of pre-clinical drug development to identify new drug targets, investigate the pathophysiology of diseases, discover potential drug candidates, and evaluate the pharmacokinetics and pharmacodynamics of drugs in vivo. Furthermore, they allow molecular imaging studies in various small-animal models of disease, including genetically engineered animals. The current collection of articles provides unique examples covering all major aspects in the field.
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This book covers topics ranging from a detailed error analysis of SSTs to new applications employed, for example, in the study of the El Niño–La Niña Southern Oscillation, lake temperatures, and coral bleaching. New techniques for interpolation and algorithm development are presented, including improvements for cloud detection. Analysis of the pixel-to-pixel uncertainties provides insight to applications for high spatial resolutions. New approaches for the estimation and evaluation of SSTs are presented. In addition, an overview of the Climate Change Initiative, with specific applications to SST, is presented. The book provides an excellent overview of the current technology, while also highlighting new technologies and their applications to new missions.
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The coordination chemistry of the s-block metals spans diverse fields, ranging from shielded coordination compounds over hydride to organometallic complexes for diverse applications. New developments pertain, not only to the lithium and magnesium chemistry with inspiring examples, such as heterobimetallic or heteroleptic complexes with special reactivity patterns, but the heavy s-block metals have progressively gained attention in various fields. Subvalent magnesium(I) derivatives are increasingly being used for reduction reactions, turbo-Grignard reagents show enhanced reactivity and tolerance toward functional groups, hydrides act as hydrogen storage materials, heavy Grignard reagents are available by straight forward procedures—just to name a few examples. Quantum chemical calculations deal with unique bonding situations and the relevance of d-orbital participation has been discussed to understand structure-reactivity relationships. Especially the complexes of the heavy alkaline earth metals are catalytically active in diverse reactions, promoting hydrofunctionalization reactions and Lewis acid catalysis. This Special Issue aims to highlight the structural and chemical diversity of s-block metal complexes, as well as the broad field of applications.
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As we all know, electrons carry both charge and spin. The processing of information in conventional electronic devices is based only on the charge of electrons. Spin electronics, or spintronics, uses the spin of electrons, as well as their charge, to process information. Metals, semiconductors, and insulators are the basic materials that constitute the components of electronic devices, and these types of materials have been transforming all aspects of society for over a century. In contrast, magnetic metals, half-metals (including zero-gap half-metals), magnetic semiconductors (including spin-gapless semiconductors), dilute magnetic semiconductors, and magnetic insulators are the materials that will form the basis for spintronic devices. This book aims to collect a range of papers on novel materials that have intriguing physical properties and numerous potential practical applications in spintronics.
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The spin-crossover (SCO) phenomenon originates from the intrinsic bistability of the d-electron configuration, created by the competition between ligand-field splitting and spin-pairing energies in a first coordination sphere of transition metal ions. Since Cambi’s visionary finding of the SCO phenomenon in 1931, considerable knowledge concerning syntheses, crystal structures, magnetic and thermodynamic properties, spectroscopies, molecular orbital calculations, and theories of SCO complexes has accumulated in a very large number of inorganic molecular coordination compounds, and, in addition, inorganic cobaltates and bioinorganic molecular systems. Recent studies which have focused on other electronic properties exhibited by SCO complexes themselves, control of molecular assemblies, and moreover, multifunctionalization of SCO complexes with either different electronic properties or porous frameworks will open the possibility toward future practical applications of SCO complexes. Thus, the fundamentals and applications of SCO complexes afford a very exciting research field in inorganic coordination chemistry and continues to attract growing attention on a wide range of relevant research fields. This Special Issue aims at collecting research and review contributions concerning recent advances in all aspects of SCO and related phenomena and disseminating this extensive knowledge with a broader audience by means of open access publishing. I invite you to contribute papers in the following research areas so that your research can impact the next generation trends in this promising field.
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This book is a collection of 13 innovative papers describing the state of the art and the future perspectives in solid-phase extraction covering several analytical fields prior to the use of gas or liquid chromatographic analysis. New sorptive materials are presented including carbon nanohorn suprastructures on paper support, melamine sponge functionalized with urea–formaldehyde co-oligomers, chiral metal–organic frameworks, UiO-66-based metal–organic frameworks, and fabric phase sorptive media for various applications. Solid-phase extraction can be applied in several formats aside from the conventional cartridges or mini-column approach, e.g., online solid-phase extraction, dispersive solid-phase microextraction, and in-syringe micro-solid-phase extraction can be very helpful for analyte pre-concentration and sample clean-up. Polycyclic musks in aqueous samples, 8-Nitroguanine in DNA by chemical derivatization antibacterial diterpenes from the roots of salvia prattii, perfluoroalkyl substances (PFASs) in aater samples by bamboo charcoal-based SPE, parabens in environmental water samples, benzotriazoles as environmental pollutants, organochlorine pesticide residues in various fruit juices and water samples and synthetic peptide purification are among the applications cited in this collection. All these outstanding contributions highlight the necessity of this analytical step, present the advantages and disadvantages of each method and focus on the green analytical chemistry guidelines that have to be fulfilled in current analytical practices.
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This Special Issue cooperates with the 5th Asian Symposium on Emulsion Polymerization and Functional Polymeric Microspheres (ASEPFPM 2015) (http://asepfpm5.csp.escience.cn). Polymeric microspheres are basic materials for recent progress in environmental science, architecture, biomedicine, electronics, food, cosmetics, etc. While much progress has been made over the past few decades, there are still big challenges for the preparation of functional particles and the verification of preparation mechanisms; there is much room for growth in our ability to provide for high performance in these areas. The general theme of this symposium is to discuss recent advances in both fundamentals and applications, as well as to promote science and industrialization translation.
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Summary/Description for Distribution Channels: The present printed edition of the Special Issue “Surface Chemistry and Catalysis” published in Catalysts aims to cover some of the recent advances in the field of heterogeneous catalysis that can be obtained by means of advanced characterization techniques, computational calculations and time-resolved methods, with particular emphasis on structure–activity relationships (SARs). It consists of 14 high-quality theoretical and experimental studies on various aspects on catalysis, involving the electrochemical promotion in catalysis, H2O dissociation, H2 production, Fisher–Tropsch synthesis, CO oxidation, among others.
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Dear Colleagues, The assembly of organic ligands and metal centres yields coordination polymers, many of which find applications in conductivity, catalysis, magnetism, gas sorption, biological sensing and luminescence. The structure and topology of coordination polymers may be manipulated by changing the reaction conditions, leading to a large variety of structurally and topologically unique products. However, controlling and predicting the final outcome of the self-assembly procedure remains one of the major challenges in the field. The final products are often strongly influenced by factors such as the behaviour of a functional group in a molecule, the influence of the crystallization conditions and the various conformations of the components within the crystal. This Special Issue aims to cover a broad range of subjects in coordination polymer chemistry, which are important to the continued growth of the field, showcase current developments and realise its full potential in applications to address major societal challenges. Therefore, we invite you to contribute a research article to this Special Issue and provide a clear snapshot of your research in this field.
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Micro-extraction techniques in sample preparation are gaining interest among analytical chemists as they comply with green analytical chemistry demands and ensure environmental protection and public safety. Savings in cost and time are considered as valuable benefits by using novel micro-extraction approaches in sample handling. Selectivity, sensitivity and lower detection limits are also included among the performance characteristics required to meet the legislation criteria. The target of this special issue is to present the state of art in microextraction sample preparation techniques. Modern, simple and efficient methods for preconcentration and separation are described for different analytes isolated from various matrices.
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The term zeolite is based on Greek words for “to boil” and “stone” and it is already known since more than 250 years. At that time, the Swedish mineralogist A.F. Cronstedt (1722-1765) observed the formation of large amount of steam when heating the material Stilbite pointing to his porous character and adsorption capacity. At present, over 200 different zeolite frameworks have been identified. In general, zeolites are crystalline aluminosilicates with defined micropore structure. Within zeolites, a good number of elements can be isomorphously incorporated and much more elements or their oxides can be hosted by zeolites. Besides their big variety in size of pore mouths, channels, crossings etc. leading also to their designation as molecular sieves and uses in membrane applications, zeolites reveal Brønsted and Lewis acidic properties that can be varied in wide limits as well. Thus, they deserve the name “solid acids”. Zeolites have an immense importance in diverse industrial applications as catalysts and adsorbents, for example in refinery industry, chemical industry, detergent sector or for solar thermal collectors and adsorption refrigeration In this special issue we aim at new developments and recent progress with respect to zeolite-catalyzed chemical reactions, adsorption applications and membrane uses as well as improved syntheses strategies and characterization techniques.
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Polymers aims to compile the current trends and research directions of internationally renowned and successful young polymer scientists in one dedicated Special Issue. The idea for this Special Issue has arisen from the numerous and, above all, brilliant nominations for our 1st Young Investigator Award. It was the easiest-ever choice for us to publicly share the fascinating and thrilling research successes of the nominated scientists with you, our dear peer readers. For this prestigious Special Issue, the journal Polymers will only accept original research papers that have been invited exclusively by the editors. The contributions to this Special Issue will highlight the current state-of-the-art in the fields of polymerization methods, theory/simulation/modeling, new physical phenomena, advances in characterization techniques, and harnessing of self-assembly and biological strategies for producing complex multifunctional structures. Please enjoy reading these high-end research highlights!
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The Special Edition 'Compounds with Polar Metallic Bonding' is a collection of eight original research reports presenting a broad variety of chemical systems, analytical methods, preparative pathways and theoretical descriptions of bonding situations, with the common aim of understanding the complex interplay of conduction electrons in intermetallic compounds that possess different types of dipoles. Coulombic dipoles introduced by electronegativity differences, electric or magnetic dipoles, polarity induced by symmetry reduction—all the possible facets of the term 'polarity'—can be observed in polar intermetallic phases and have their own and, in most cases, unique consequences on the physical and chemical behaviour. Elucidation of the structure–property relationships in compounds with polar metallic bonding is a modern and growing scientific field which combines solid state physics, preparative chemistry, metallurgy, modern analytic methods, crystallography, theoretical calculations of the electronic state and many more disciplines.
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This book contains a collection of twelve state-of-the-art, original papers with results from contemporary research in the syntheses and uses of nucleosides and nucleoside analogues, as well as two reviews on contemporary methodology to modify nucleosides.
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The market is continuously looking for substitutes for expensive polymers or tailor made polymers for specific applications. Therefore, polymer blends are gaining more interest since they possess a great potential to fulfill these needs. Blending not only results in better final properties, but can also improve the processing behavior and reduce costs. In the field of polymer blends, there are numerous parameters that influence the morphology, e.g., viscosity ratio, blend composition, shear conditions, and blend ratio. There is still a great deal of potential to scientifically exploit the possibilities of blend technology, which is necessary to obtain a foundation based on science, engineering, technology, and applications in order to make it possible to tailor polymer blends as desired. However, combining two or more different polymers to receive favorable properties by blending often results in immiscible polymer blends. This immiscibility goes hand-in-hand with phase separation leading to weak mechanical properties. The high interfacial tension causing this can be reduced by compatibilization of polymer blends. There are different methods to achieve this, such as adding block and graft copolymers, reactive polymers to form block and graft copolymers, nanoparticles or organic molecules. Using suitable compatibilizers, not only is the interfacial adhesion between matrix and its blends reduced, but also the dispersion of the dispersed phase is improved, the adhesion between the phases is enhanced and the morphology is stabilized. This can lead to improved mechanical and morphological properties. Designing new polymer blends or improving the properties of immiscible polymer blends by compatibilization is very challenging, but an excellent way to exploit the full potential of polymers for applications and their varied needs. This Special Issue is a source of information on all recent aspects of polymer blend technology.
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As the fields of organometallic and coordination chemistry of the transition metals has grown more mature, the under-explored chemistry of the rare-earths and actinides has drawn the attention of research groups from across the globe looking for new fundamental discoveries and access to compounds with unique properties. The rare-earths—the group 3 metals and the 4f lanthanide series—have long shown many interesting properties in the solid state which exploit their unique electronic configurations. However, it is the molecular chemistry of these metals that has expanded dramatically in recent years as researchers identify the differences between—and unique features of—their molecular compounds. Recent highlights include the identification of new oxidation states and patterns of reactivity as well as applications in medical imaging and health care which represent new and exciting areas of research. The actinides show a wide range of different properties as a consequence of their radioactivity and radiochemistry, but this has not stopped recent rapid progress into the exploration of their unique chemistry. Uranium, in particular, shows huge potential with its transition metal-like range of oxidation states (+2 to +6), and in specialised laboratories, the heavier actinides are also beginning to show their unique chemistry. This Special Issue aims to bring together these strands of research in an openly-accessible way to allow better communication of these advances to a wider audience. This is necessary as, despite these exciting advances, the rare-earths and actinides are still much neglected topics in both school and undergraduate curriculums. Contributions in the above-mentioned areas will allow new research in the rare-earths and actinides to inform and influence the next generation of scientists and keep the field as vibrant as it is today.
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Molecular magnets show many properties not met in conventional metallic magnetic materials, i.e. low density, transparency to electromagnetic radiation, sensitivity to external stimuli such as light, pressure, temperature, chemical modification or magnetic/electric fields, and others. They can serve as “functional” materials in sensors of different types or be applied in high-density magnetic storage or nanoscale devices. Research into molecule-based materials became more intense at the end of the 20th century and is now an important branch of modern science. The articles in this Special Issue, written by physicists and chemists, reflect the current work on molecular magnets being carried out in several research centers. Theoretical papers in the issue concern the influence of spin anisotropy in the low dimensional lattice of the resulting type of magnet, as well as thermodynamics and magnetic excitations in spin trimers. The impact of external pressure on structural and magnetic properties and its underlying mechanisms is described using the example of Prussian blue analogue data. The other functionality discussed is the magnetocaloric effect, investigated in coordination polymers and high spin clusters. In this issue, new molecular magnets are presented: (i) ferromagnetic high-spin [Mn6] single-molecule magnets, (ii) solvatomagnetic compounds changing their structure and magnetism dependent on water content, and (iii) a family of purely organic magnetic materials. Finally, an advanced calorimetric study of anisotropy in magnetic molecular superconductors is reviewed.
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This computational study investigates diverse bonding situations in nanostructures (carbon nanotubes, fullerenes, metal compounds) spanning a broad range of energies. Weak, dispersive interactions and covalent metal-ligand and metal-metal bonding are examined. The results of efficient density functional calculations are compared to those of correlated wavefunction calculations on model systems. This rigorous validation is crucial in evaluating the balance between computational cost and accuracy.
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The scarcity of potable water is a great challenge. It may be resolved by the desalination of seawater. In this work, the possibilities of a new desalination technique using polymeric hydrogels as a separation medium for water and salt is explored. The bound charges in such a polymeric network prevent salt from entering it - under pressure the desalinated water is released from the gel. It is demonstrated that the method is viable and the influence of various process parameters investigated.
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ca. 200 words; this text will present the book in all promotional forms (e.g. flyers). Please describe the book in straightforward and consumer-friendly terms. [In the last decades, nanoscience and nanotechnologies have offered new opportunities for producing materials with structural and functional properties. The possibility to manipulate the matter, on an atomic or molecular level, can allow the obtainment of structures having unique characteristics and completely new functionalities. The use of structural and functional nanoparticles to be added to polymer nanocomposites is a nice way to manipulate the matter’s properties following a bottom-up approach. The hybrid fillers can be used, not only as for structural purposes, but also as functional nano-structures in many fields, such as microelectronics, packaging, drug delivery, flame retardant materials, and environmental issues. A number of interesting nanoparticles, such as clays (lamellar or tubular), silica, carbon nanotubes, siloxanes, and, more recently, graphenes, have emerged as peculiar nanofillers for enhancing the performance of polymer matrices for a wide variety of technological applications. The present chapter aims to present the last research and novelty in the field of polymeric nanocomposites’ materials. Methods of productions, as well as polymers and type and shape of the fillers and their functionalities are widely reported. Structural organization and physical properties of the polymer matrix are correlated with the nature of filler
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This book covers topics ranging from a detailed error analysis of SSTs to new applications employed, for example, in the study of the El Niño–La Niña Southern Oscillation, lake temperatures, and coral bleaching. New techniques for interpolation and algorithm development are presented, including improvements for cloud detection. Analysis of the pixel-to-pixel uncertainties provides insight to applications for high spatial resolutions. New approaches for the estimation and evaluation of SSTs are presented. In addition, an overview of the Climate Change Initiative, with specific applications to SST, is presented. The book provides an excellent overview of the current technology, while also highlighting new technologies and their applications to new missions.
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This Special Issue serves as a crystallographic forum covering various aspects of material science that have in common the use of the powerful Rietveld method in the analysis of the powder XRD patterns of investigated compounds.
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The QM/MM method, short for quantum mechanical/molecular mechanical, is a highly versatile approach for the study of chemical phenomena, combining the accuracy of quantum chemistry to describe the region of interest with the efficiency of molecular mechanical potentials to represent the remaining part of the system. Originally conceived in the 1970s by the influential work of the the Nobel laureates Martin Karplus, Michael Levitt and Arieh Warshel, QM/MM techniques have evolved into one of the most accurate and general approaches to investigate the properties of chemical systems via computational methods. Whereas the first applications have been focused on studies of organic and biomolecular systems, a large variety of QM/MM implementations have been developed over the last decades, extending the range of applicability to address research questions relevant for both solution and solid-state chemistry as well. Despite approaching their 50th anniversary in 2022, the formulation of improved QM/MM methods is still an active field of research, with the aim to (i) extend the applicability to address an even broader range of research questions in chemistry and related disciplines, and (ii) further push the accuracy achieved in the QM/MM description beyond that of established formulations. While being a highly successful approach on its own, the combination of the QM/MM strategy with other established theoretical techniques greatly extends the capabilities of the computational approaches. For instance the integration of a suitable QM/MM technique into the highly successful Monte-Carlo and molecular dynamics simulation protocols enables the description of the chemical systems on the basis of an ensemble that is in part constructed on a quantum-mechanical basis. This eBook presents the contributions of a recent Research Topic published in Frontiers in Chemistry, that highlight novel approaches as well as advanced applications of QM/MM method to a broad variety of targets. In total 2 review articles and 10 original research contributions from 48 authors are presented, covering 12 different countries on four continents. The range of research questions addressed by the individual contributions provide a lucid overview on the versatility of the QM/MM method, and demonstrate the general applicability and accuracy that can be achieved for different problems in chemical sciences. Together with the development of improved algorithms to enhance the capabilities of quantum chemical methods and the continuous advancement in the capacities of computational resources, it can be expected that the impact of QM/MM methods in chemical sciences will be further increased already in the near future.
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The fluorine nucleus, when introduced as a reporter group in membrane-associated proteins or peptides, offers a highly sensitive alternative to conventional isotope labels in solid-state NMR spectroscopy. The study presented here is concerned with the development of 19F-NMR methods, as well as data analysis schemes to extract the wealth of structural and motional information from the spectra.
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The use of solid catalysts for the upgrade of renewable sources gives the opportunity to combine the two main cores of green chemistry, that is, on the one hand, the set-up of sustainable processes and, on the other, the use of biomass-derived materials. Solid catalysts have taken on a leading role in traditional petrochemical processes and could represent a key tool in new biorefinery-driven technologies.
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The treatise is the first coherent and comprehensive presentation of the important sub-field of ""technology entrepreneurship"" emphasizing the science and engineering perspectives. It is a presentation of technology entrepreneurship as an inter-cultural approach referring to the US and Germany. It integrates micro- and macro aspects referring to numerous cases of firms' foundations. The book provides also a new semi-quantitative approach to growth of new technology ventures.
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The treatise is the first coherent and comprehensive presentation of the important sub-field of ""technology entrepreneurship"" emphasizing the science and engineering perspectives. It is a presentation of technology entrepreneurship as an inter-cultural approach referring to the US and Germany. It integrates micro- and macro aspects referring to numerous cases of firms' foundations. The book provides also a new semi-quantitative approach to growth of new technology ventures.
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ca. 200 words; this text will present the book in all promotional forms (e.g. flyers). Please describe the book in straightforward and consumer-friendly terms. [Although the technological and scientific importance of functional polymers have been well established over the last few decades, the most recent focus that has attracted much attention concerns stimuli-responsive polymer gels. These materials are of particular interest due to their abilities to respond to internal and/or external chemo-physical stimuli. Aside from the scientific challenges of designing stimuli-responsive polymer gels, the main technological interests concern numerous applications, ranging from catalysis in microsystem technology and chemo-mechanical actuators to sensors. This Special Issue includes seventeen papers covering a wide range of subjects including thermo- and pH-responsive hydrogels, functionalized materials, supramolecular stimuli-responsive structures, composite hydrogels, sensors, and biomedical applications. Together, these contributions not only provide an excellent overview of the current state-of-the-art in the field but also point out exciting challenges and opportunities for future work. In a number of reviews the most recent findings on “Stimuli-Responsive Gels” are compiled in this book supplemented by original contributions.
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The photoinduced dynamics of radical precursors in solution were investigated by means of femtosecond transient absorption spectroscopy assisted by quantum chemical calculations. The investigated systems show a wide range of excited state lifetimes ranging from tens of femtoseconds to nanoseconds. Thus, in the first case, on the investigated time scale the dynamics of the generated radicals can be additionally investigated. In the latter case only the excited singlet lifetime is observable.
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Ultraschnelle Dynamik von verschiedenen organischen und anorganischen molekularen Systemen wurde unter Verwendung der zeitaufgelöste Anregungs-Abfrage-Technik in Kombination mit anderen spektroskopischen Methoden untersucht. Diese Dynamik umfasst, z.B. die Relaxationsprozesse in Metalloporphyrins, die Ladungstransfer zwischen Donor und Akzeptor durch DANN-Doppelhelix sowie die Dynamik von Ladungsträger in anorganischen nanostrukturierten zyklischen koordinierten Eisen-Lanthanoide Clustern. v
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Titanium is a good example of a material that is globally recognized for its outstanding properties, making it desirable for a range of industries. Titanium and its alloys are utilized in a wide range of industries, including aerospace, automotive and high performance leisure equipment. This Special Issue of Metals focusing on titanium contains a range of articles based on research into this fascinating material and its wide range of alloys. For applications that can withstand the high basic cost of titanium it is shown that the unique properties of the material have the potential to provide further performance improvements to existing industries, whilst offering new opportunities to emerging markets.
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The emission of dibenzofurans and dioxins from industrial processes is a major environmental concern. Focussing on dibenzofuran, this study tend to improve our understanding of the general oxidation chemistry and to provide a mechanism suitable for future modelling studies.Based on quantum chemical methods, energies, chemical structures and reactions are calculated numerically. Not only stable molecules and radicals, but also transition states are reported in this work.
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Nowadays, transition metal-oxides can be considered the most investigated materials especially in their nanostructured forms thanks to their intrinsic smart properties and to the positive effects induced by scaling their dimension down to the nanoscale. Among them, ZnO and TiO2 have attracted particular interest mainly because of their multi-functionality applicable in an enormous range of research fields. The present Special Issue – composed by twenty-seven papers, both reviews and research articles - covers the most recent advances in ZnO and TiO2 nanostructures, concerning not only their synthesis and characterization, but also reports of the manner(s) in which their functional and smart properties can be applied in working devices. Applications of such nanostructures can range widely, from biomedical and drug delivery devices to piezoelectric and chemical sensors, and energy harvesting, conversion, and storage devices.
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The summary should be ca. 200 words; this text will present the book in all promotional forms (e.g. flyers). Please describe the book in straightforward and consumer-friendly terms. [Zinc oxide (ZnO) is a wide band gap semiconductor with an energy gap of 3.37 eV at room temperature. It has been used considerably for its catalytic, electrical, optoelectronic, and photochemical properties. ZnO nanomaterials, such as quantum dots, nanorods, and nanowires, have been intensively investigated for their important properties. Many methods have been described in the literature for the production of ZnO nanostructures, such as laser ablation, hydrothermal methods, electrochemical deposition, sol-gel methods, chemical vapour deposition, molecular beam epitaxy, the common thermal evaporation method, and the soft chemical solution method. The present Special Issue is devoted to the synthesis and characterization of ZnO nanostructures with novel technological applications.
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Dear Colleagues, Determinations of the indentation hardness properties of crystals have expanded to cover the full characterizations of their important elastic, plastic and cracking behaviors, particularly as accomplished with the increased measuring capabilities of nanoindentation hardness testing. No crystal structure of any bonding type is either too soft or too hard to prevent measurement with a suitable probing indenter. The current Special Issue is devoted to surveying the topic with emphasis given in a collection of reports to: (1) the diversity of crystals being tested; (2) the variety of measuring techniques; and (3) the wealth of information being obtained. Prof. Dr. Ron Armstrong Dr. Stephen Walley Prof. Dr. Wayne L. Elban Guest Editors
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Over the past decades, the field of molecular imaging has been rapidly growing involving multiple disciplines such as medicine, biology, chemistry, pharmacology and biomedical engineering. Any molecular imaging procedure requires an imaging probe that is an agent used to visualize, characterize and quantify biological processes in living systems. Such a probe typically consists of an agent that usually produces signal for imaging purpose, a targeting moiety, and a linker connecting the targeting moiety and the signaling agent. Many challenging problems of molecular imaging can be addressed by exploiting the great possibilities offered by modern synthetic organic and coordination chemistry and the powerful procedures provided by conjugation chemistry. Thus, chemistry plays a decisive role in the development of this cutting-edge methodology. Currently, the diagnostic imaging modalities include Magnetic Resonance Imaging (MRI), Computed Tomography (CT), Ultrasound (US), Nuclear Imaging (PET, SPECT), Optical Imaging (OI) and Photoacoustic Imaging (PAI). Each of these imaging modalities has its own advantages and disadvantages, and therefore, a multimodal approach combining two techniques is often adopted to generate complementary anatomical and functional information of the disease. The basis for designing imaging probes for a given application is dictated by the chosen imaging modality, which in turn is dependent upon the concentration and localization profile (vascular, extracellular matrix, cell membrane, intracellular, near or at the cell nucleus) of the target molecule. The development of high-affinity ligands and their conjugation to the targeting vector is also one of the key steps for pursuing efficient molecular imaging probes. Other excellent reviews, text and monographs describe the principles of biomedical imaging, focusing on molecular biology or on the physics behind the techniques. This Research Topic aims to show how chemistry can offer molecular imaging the opportunity to express all its potential.
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Bacterial proliferation is a severe and increasing concern in everyday life, which accounts for important damage in a number of industries, from textile and marine transport to medicine and food packaging. Despite the huge efforts by academic and industry researchers, a universal solution for controlling bacterial colonization has not been established yet. In this regard, nanomaterials are more and more used to target bacteria as an alternative to antibiotics. Examples include the use of nanomaterials in antibacterial coatings for implantable devices and other materials to prevent infection and promote wound healing and in antibiotic delivery systems to treat diseases. By exploiting the excellent antibacterial properties of some materials at the nanoscale, namely ZnO, TiO2, Ag, Au, nanodiamond and graphene, effective strategies for the prevention of infections can be developed. The main focus of this book is, therefore, to present selected examples of the most recent advances in the synthesis, characterization, and applications of nanomaterials with antibacterial activity. The book is addressed to scientists and industry researchers, as well as to master and degree students in chemistry, pharmacy, bioengineering, biology and materials science. The Editor would like to thank the staff of Nanomaterials Editorial Office for the constant help and support.
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Nowadays the application of multisensor systems for the analysis of liquids and gases is becoming more and more popular in analytical chemistry. Such systems, also known as “electronic tongues” and “electronic noses” are based on various types of chemical sensors and biosensors with different transduction principles combined with multivariate data processing protocols. These instruments received significant interest due to their simplicity, low costs and the possibility to obtain reliable chemical information from complex unresolved analytical signals. A distinct feature of electronic tongues and noses is that they can be calibrated for prediction of complex integral features in samples, like e.g. taste, odor, toxicity, geographical origin, general conformity with certain standards, etc. – the tasks that otherwise would require involvement of complex analytical instrumentation, human or animal sensory panels. In the present eBook the original research and review articles in the area of multisensor approach are collected. They dedicated to the novel sensor materials development, measuring techniques evaluation, electronics, data processing protocols and practical applications. An editorial foreword article is followed by the researches authored by leading scientists in the field of chemical sensors and artificial sensing systems. With this eBook we hope to inspire further interest and new research efforts in this exciting area.
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Bacterial proliferation is a severe and increasing concern in everyday life, which accounts for important damage in a number of industries, from textile and marine transport to medicine and food packaging. Despite the huge efforts by academic and industry researchers, a universal solution for controlling bacterial colonization has not been established yet. In this regard, nanomaterials are more and more used to target bacteria as an alternative to antibiotics. Examples include the use of nanomaterials in antibacterial coatings for implantable devices and other materials to prevent infection and promote wound healing and in antibiotic delivery systems to treat diseases. By exploiting the excellent antibacterial properties of some materials at the nanoscale, namely ZnO, TiO2, Ag, Au, nanodiamond and graphene, effective strategies for the prevention of infections can be developed.The main focus of this book is, therefore, to present selected examples of the most recent advances in the synthesis, characterization, and applications of nanomaterials with antibacterial activity. The book is addressed to scientists and industry researchers, as well as to master and degree students in chemistry, pharmacy, bioengineering, biology and materials science. The Editor would like to thank the staff of Nanomaterials Editorial Office for the constant help and support.
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The use of nanotechnologies in the food-packaging area has opened up a number of possibilities derived from the inherent characteristics of nanoadditives, which can either improve relevant properties of neat polymers (such as barrier or mechanical properties) or introduce new functionalities (for active and bioactive packaging applications or even for sensing). This is an exciting and rapidly growing field of study, and very interesting developments are unfolding. Although the aim of these novel materials is to improve packaged food quality and safety, the toxicological effects derived from their potential migration from the polymer structures is also under consideration. This Special Issue compiles a review and five original papers describing novel nanocomposites with improved packaging properties, the use of nanotechnologies for smart packaging applications, and nanoparticle migration studies from novel nanocomposites.
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Discontinuous fiber-reinforced polymers have gained importance in the transportation industries due to their outstanding material properties, lower manufacturing costs and superior lightweight characteristics. One of the most attractive attributes of discontinuous fiber reinforced composites is the ease with which they can be manufactured in large numbers, using injection and compression molding processes. Typical processes involving discontinuous fiber reinforced thermoplastic composite materials include injection and compression molding processes as well as extrusion. Furthermore, the automotive and appliance industries also use thermosets reinforced with chopped fibers in the form of sheet molding compound and bulk molding compound, for compression and injection-compression molding processes, respectively. A big disadvantage of discontinuous fiber composites is that the configuration of the reinforcing fibers is significantly changed throughout production process, reflected in the form of fiber attrition, excessive fiber orientation, fiber jamming and fiber matrix separation. This process-induced variation of the microstructural fiber properties within the molded part introduces heterogeneity and anisotropies to the mechanical properties, which can limit the potential of discontinuous fiber reinforced composites for lightweight applications. The main aim of this Special Issue is to collect various investigations focused on the processing of discontinuous fiber reinforced composites and the effect processing has on fiber orientation, fiber length and fiber density distributions throughout the final part. Papers presenting investigations on the effect fiber configurations have on the mechanical properties of the final composite products and materials are welcome in the Special Issue. Researchers who are modeling and simulating processes involving discontinuous fiber composites as well as those performing experimental studies involving these composites are welcomed to submit papers. Authors are encouraged to present new models, constitutive laws and measuring and monitoring techniques to provide a complete framework on these groundbreaking materials and facilitate their use in different engineering applications.
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This book is a printed edition of the Special Issue Crystal Chemistry of Zinc, Cadmium and Mercury that was published in Crystals
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Today, the development of active and stable catalysts still represents a challenge to overcome in the research field of low temperature fuel cells. Operation at low temperatures demands the utilization of highly active catalysts to reduce the activation energy of the electrochemical reactions involved at the electrodes, and thus obtain practical performances and high efficiencies. At present, the most practical catalysts in low temperature fuel cells are highly dispersed Pt nanoparticles. However, these present several drawbacks such as high cost, limited earth resources, sensitivity to contaminants, low tolerance to the presence of alcohols and stability due to carbon support corrosion and Pt dissolution. In the search for alternative catalysts, researchers have looked at several strategies: increase of the utilization of Pt catalysts by means of novel structures (metal/support), alloying with non-platinum metals, new carbon and non-carbon supports, cheaper platinum-group-metals like Pd, non-platinum-group metals catalysts (Fe-N-C, Co-N-C, etc.), etc. This book is intended to cover the most recent progresses in advanced electro-catalysts from the synthesis and characterization to the evaluation of performance and degradation mechanisms, in order to gain insights towards the development of highly active fuel cells.
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The forming of metals through plastic deformation comprises a family of methods that produce components through the re-shaping of input stock, oftentimes with little waste. Therefore, forming is one of the most efficient and economical manufacturing process families available. A myriad of forming processes exist in this family. In conjunction with their countless existing successful applications and their relatively low energy requirements, these processes are an indispensable part of our future. However, despite the vast accumulated know-how, research challenges remain, be they related to the forming of new materials (e.g., for light-weight transportation applications), pushing the boundaries of what is doable, reducing the intermediate steps and/or scrap, or further enhancing the environmental friendliness. The purpose of this book is to collect expert views and contributions on the current state-of-the-art of plastic forming, thus highlighting contemporary challenges and offering ideas and solutions.
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This is the first machine-generated scientific book in chemistry published by Springer Nature. Serving as an innovative prototype defining the current status of the technology, it also provides an overview about the latest trends of lithium-ion batteries research.
This book explores future ways of informing researchers and professionals. State-of-the-art computer algorithms were applied to: select relevant sources from Springer Nature publications, arrange these in a topical order, and provide succinct summaries of these articles. The result is a cross-corpora auto-summarization of current texts, organized by means of a similarity-based clustering routine in coherent chapters and sections.
This book summarizes more than 150 research articles published from 2016 to 2018 and provides an informative and concise overview of recent research into anode and cathode materials as well as further aspects such as separators, polymer electrolytes, thermal behavior and modelling.
With this prototype, Springer Nature has begun an innovative journey to explore the field of machine-generated content and to find answers to the manifold questions on this fascinating topic. Therefore it was intentionally decided not to manually polish or copy-edit any of the texts so as to highlight the current status and remaining boundaries of machine-generated content.
Our goal is to initiate a broad discussion, together with the research community and domain experts, about the future opportunities, challenges and limitations of this technology.
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Natural and chemical compounds, often used as both dietary supplements and alternative medicines, are characterized by specific chemical properties, allowing their passage across the blood brain barrier with consequent specific effects on neurotransmission. In particular, several natural compounds have shown beneficial properties in the treatment of neuropsychiatric disorders, especially cognitive impairment and mood disorders, contributing to the maintenance of the physiological brain functioning by interacting with different receptors, transcription factors and signal transduction pathways. Neuroinflammation and oxidative stress have also been proposed as crucial contributors to brain dysfunction development, thus recent investigations have focused on novel therapeutic approaches based on the use of phytoderivates with neuroprotective properties. Thus, this Special Issue includes a collection of 11 papers, describing key findings for the identification of molecular mechanisms required for the development of potential and promising natural therapeutics for the treatment of psychiatric and neurodegenerative disorders.
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Polyamines are small aliphatic polycations which have been involved in key stress and developmental processes in plants. In the recent years, compelling genetic and molecular evidences point to polyamines as essential metabolites required for resistance to drought, freezing, salinity, oxidative stress among other type of abiotic and biotic stresses. In addition to their role as stress-protective compounds, polyamines participate in key developmental processes mediated by specific signaling pathways or in cross-regulation with other plant hormones. Our Research Topic aims to integrate the multiple stress and developmental regulatory functions of polyamines in plants under a genetic, molecular and evolutionary perspective with special focus on signaling networks, mechanisms of action and metabolism regulation.
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Plants are the most important renewable source of feedstock for polymeric materials. They are a resource of monomers and macromolecules after the appropriate chemical treatment. By analogy with the petrochemistry industry, plant macromolecules are depolymerized into simpler units which are generally chemically modified and re-bound to produce new polymers. The properties of these polymers are usually tailored by small chemical changes in their molecular structure, or by the polymerization of plant monomers with other molecules. Another interesting strategy for the formation of polymeric materials is the direct use of plant macromolecules in the form of blends, composites, grafted polymers, multilayer systems, etc. The interactions and assemblies of the different components allow the control of the final features of such materials. Traditionally, polysaccharides, with cellulose as the main protagonist, have been the most used substances. However, as consequence of a growing demand of functional plastics, other plant macromolecules, habitually considered wastes, have started to become valuable raw materials. Lignin and plant proteins (mainly, soy protein, wheat gluten, and zein) are classical examples. Also, suberin has been highlighted in this field. Other plant polymers such as the cutin and the sporopollenin are promising alternatives. Furthermore, other minority plant polymers, e.g. cutan or algaenan, could be potential sources of materials. The different chemistry, structure, intrinsic properties and functions of these macromolecules in the plants are a strong inspiration for the development of novel and interesting polymeric materials. Here, in this Research Topic, we welcome the submission of manuscripts related to the production, extraction, processability, synthesis, characterization and applications of non-polysaccharides plant materials.
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This book is a printed edition of the Special Issue Molecular Modeling in Drug Design that was published in Molecules
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The human genome, as with the genome of most organisms, is comprised of various types of mobile genetic element derived repeats. Mobile genetic elements that mobilize by an RNA intermediate, include both autonomous and non-autonomous retrotransposons, and mobilize by a “copy and paste” mechanism that relies of the presence of a functional reverse transcriptase activity. The extent to which these different types of elements are actively mobilizing varies among organisms, as revealed with the advent of Next Generation DNA sequencing (NGS).To understand the normal and aberrant mechanisms that impact the mobility of these elements requires a more extensive understanding of how these elements interact with molecular pathways of the cell, including DNA repair, recombination and chromatin. In addition, epigenetic based-mechanisms can also influence the mobility of these elements, likely by transcriptional activation or repression in certain cell types. Studies regarding how mobile genetic elements interface and evolve with these pathways will rely on genomic studies from various model organisms. In addition, the mechanistic details of how these elements are regulated will continue to be elucidated with the use of genetic, biochemical, molecular, cellular, and bioinformatic approaches. Remarkably, the current understanding regarding the biology of these elements in the human genome, suggests these elements may impact developmental biology, including cellular differentiation, neuronal development, and immune function. Thus, aberrant changes in these molecular pathways may also impact disease, including neuronal degeneration, autoimmunity, and cancer.
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Oceans include the greatest extremes of pressure, temperature and light, and habitats can range from tropical waters to ocean trenches, several kilometers below sea level at high pressure. With its 70% of the surface of our planet marine ecosystem still remains largely unexplored, understudied and underexploited in comparison with terrestrial ecosystems, organisms and bioprocesses. The biological adaptation of marine organisms to a wide range of environmental conditions in the specific environment (temperature, salinity, tides, pressure, radiation, light, etc.) has made them an enormous reservoir of interesting biological material for both basic research and biotechnological improvements. As a consequence marine ecosystem is valued as a source of enzymes and other biomolecules exhibiting new functions and activities to fulfill human needs. Indeed, in recent years it has been recognised as an untapped source of novel enzymes and metabolites even though, with regard to the assignment of precise biological functions to genes, proteins and enzymes, it is still considered as the least developed. Using metagenomics to recover genetic material directly from environmental samples, this biogenetic diversification can be accessed but despite the contributions from metagenomic technologies the new field requires major improvements. A few words on the complexity of marine environments should be added here. This complexity ranges from symbiotic relationships to biology and chemistry of defence mechanisms and from chemoecology of marine invasions up to the strategies found in prokaryotes to adapt to extreme environments. The interdisciplinary study of this complexity will enable researchers to find an arsenal of enzymes and pathways greatly demanded in biotechnological applications. As far as marine enzymes are concerned they may carry novel chemical and stereochemical properties, thus biocatalytically oriented studies (testing of suitable substrates, appropriate checking of reaction conditions, study of stereochemical asset of catalysis) should be performed to appropriately reveal this “chemical biodiversity” which increases interest for these enzymes. Among other biomolecules, polysaccharides are the most abundant renewable biomaterial found on land and in oceans. Their molecular diversity is very interesting; except polysaccharides used traditionally in food and non-food industries, the structure and the functionality of most of them are unknown and unexplored. Brown seaweeds synthesize unique bioactive polysaccharides: laminarans, alginic acids and fucoidans. A wide range of biological activities (anticoagulant, antitumor, antiviral, anti-inflammation, etc.) have been attributed to fucoidans and their role with respect to structure-activity relationship is still under debate. In this Research Topic, we wish to centralize and review contributions, idea and comments related to the issues above. In particular results of enzymatic bioprospecting in gross marine environment will be acknowledged along with research for structural characterization and biological function of biomolecules such as marine polysaccharides and all kind of research related to the complexity of bioprocesses in marine environments. Inter- and multi-disciplinary approach to this field is favoured in this Research Topic and could greatly be facilitated by the web and open access nature as well.
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A substantial increase in the number of studies using the optical properties (absorbance and fluorescence) of dissolved organic matter (DOM) as a proxy for its chemical properties in estuaries and the coastal and open ocean has occurred during the last decade. We are making progress on finding the actual chemical compounds or phenomena responsible for DOM’s optical properties. Ultrahigh resolution mass spectrometry, in particular, has made important progress in making the key connections between optics and chemistry. But serious questions remain and the last major special issue on DOM optics and chemistry occurred nearly 10 years ago. Controversies remain from the non-specific optical properties of DOM that are not linked to discrete sources, and sometimes provide conflicting information. The use of optics, which is relatively easier to employ in synoptic and high resolution sampling to determine chemistry, is a critical connection to make and can lead to major advances in our understanding of organic matter cycling in all aquatic ecosystems. The contentions and controversies raised by our poor understanding of the linkages between optics and chemistry of DOM are bottlenecks that need to be addressed and overcome.
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Lignans are a class of natural products found mainly in plants. They have a wide variety of structures and exhibit a range of potent biological activities. Lignans are also well-known components of a number of widely eaten foods and are frequently studied for their dietary impact. Owing to these factors, lignans have been extensively studied by scientists from a large number of disciplines. This collection of research and review articles describes topics ranging in scope from the recent isolation and structural elucidation of new lignans, strategies towards the chemical synthesis of lignans, assessment of their biological activities and potential for further therapeutic development. Research showing the impact of lignans in the food and agricultural industries is also presented.
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We are very pleased to introduce the Book Version of our Special Issue in Molecules dedicated to the memory of the late Professor Dr. Charles D. Hufford. The issue has been a huge success, with 22 full-length peer-reviewed papers and a tribute by Professor Alice M.Clark. Authors, reviewers, and collaborators from many countries across the worldhave contributed to this endeavour, and we are truly grateful to all. This Special Issue isrepresentative of the broad impact that “Charlie” had on the field of bioactive naturalproducts. This Special Issue comprises papers from Professor Hufford’s former students,colleagues, and collaborators throughout the world who have utilized a wide array ofstate-of-the-art techniques to examine diverse natural sources to isolate and identify avariety of natural products with a wide spectrum of biological activities, including somenew microbial transformations and insights into bioactive molecules. Many new bioactive compounds are described and reported here for the first time. Bioactivities reportedinclude cytotoxicity, antimicrobial activity, anti-inflammatory activity, antileishmanialactivity, antitrypanosomal activity, antimalarial activity, analgesic activity, and beneficialliver activities, just to name a few. This Special Issue will undoubtedly have a lasting impact on the field of bioactive natural products, as exemplified by the career of Dr. Hufford.Lastly, without the timely and outstanding contributions from all of you, this Special Issue would not have been possible. We thank you all very much for your contributions and your time devoted to this Special Issue in memory of a special person. Finally, we express ourgratitude and thanks to the journal Molecules and their excellent team of expert reviewers for giving us the support and opportunity to make this Special Issue a huge success!
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[This book is a printed edition of the Special Issue of Crystals: High-Pressure Studies of Crystalline Materials. It also includes additional articles published in Crystals and related to the topic of the Special Issue, which have been selected based upon their relevance and scientific quality.]
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Since its inception, the Deep Carbon Observatory (DCO) has coalesced a multidisciplinary and international group of researchers focused on understanding and quantifying Earth’s deep carbon budget. Carbon is the fourth most abundant element in the universe, and understanding carbon chemistry under a variety of environmental conditions impacts all aspects of planetary sciences, including planet formation, the form and function of planetary interiors, and the origin and diversity of life. DCO recognizes that is integrating and promoting the contributions of early career scientists are integral to the advancement of knowledge regarding the quantities, movements, origins, and forms of Earth’s deep carbon through field, experimental, analytical, and computational research. Early career scientists represent the future of deep carbon science and contribute substantially to ongoing research by implementing innovative ideas, challenging traditional working schemes, and bringing a globally interconnected perspective to the scientific community. This research topic highlights the contributions at the forefront of deep carbon research by DCO Early Career Scientist community. The manuscripts of this Frontiers e-volume bear evidence of the rapid advances in deep carbon science, and highlights the importance of approaching this field from a plethora of different angles integrating disciplines as diverse as mineralogy, geochemistry and microbiology. This integration is fundamental in understanding the movements and transformations of carbon across its deep cycle.
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The chemistry of silicon has always been a field of major concern due to its proximity to carbon on the periodic table. From the molecular chemist's viewpoint, one of the most interesting differences between carbon and silicon is their divergent coordination behavior. In fact, silicon is prone to form hyper-coordinate organosilicon complexes, and, as conveyed by reports in the literature, highly sophisticated ligand systems are required to furnish low-coordinate organosilicon complexes. Tremendous progress in experimental, as well as computational, techniques has granted synthetic access to a broad range of coordination numbers for silicon, and the scientific endeavor, which was ongoing for decades, was rewarded with landmark discoveries in the field of organosilicon chemistry. Molecular congeners of silicon(0), as well as silicon oxides, were unveiled, and the prominent group 14 metalloid proved its applicability in homogenous catalysis as a supportive ligand or even as a center of catalytic activity. This book focuses on the most recent advances in the coordination chemistry of silicon with transition metals as well as main group elements, including the stabilization of low-valent silicon species through the coordination of electron donor ligands. Therefore, this book is associated with the development of novel synthetic methodologies, structural elucidations, bonding analysis, and also possible applications in catalysis or chemical transformations using related organosilicon compounds.
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Over the past decades, the field of molecular imaging has been rapidly growing involving multiple disciplines such as medicine, biology, chemistry, pharmacology and biomedical engineering. Any molecular imaging procedure requires an imaging probe that is an agent used to visualize, characterize and quantify biological processes in living systems. Such a probe typically consists of an agent that usually produces signal for imaging purpose, a targeting moiety, and a linker connecting the targeting moiety and the signaling agent. Many challenging problems of molecular imaging can be addressed by exploiting the great possibilities offered by modern synthetic organic and coordination chemistry and the powerful procedures provided by conjugation chemistry. Thus, chemistry plays a decisive role in the development of this cutting-edge methodology. Currently, the diagnostic imaging modalities include Magnetic Resonance Imaging (MRI), Computed Tomography (CT), Ultrasound (US), Nuclear Imaging (PET, SPECT), Optical Imaging (OI) and Photoacoustic Imaging (PAI). Each of these imaging modalities has its own advantages and disadvantages, and therefore, a multimodal approach combining two techniques is often adopted to generate complementary anatomical and functional information of the disease. The basis for designing imaging probes for a given application is dictated by the chosen imaging modality, which in turn is dependent upon the concentration and localization profile (vascular, extracellular matrix, cell membrane, intracellular, near or at the cell nucleus) of the target molecule. The development of high-affinity ligands and their conjugation to the targeting vector is also one of the key steps for pursuing efficient molecular imaging probes. Other excellent reviews, text and monographs describe the principles of biomedical imaging, focusing on molecular biology or on the physics behind the techniques. This Research Topic aims to show how chemistry can offer molecular imaging the opportunity to express all its potential.
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This Issue contains one communication, six articles, and two reviews. The communication from Paola Vitale et al. represents a work where whole cells were used as biocatalysts for the reduction of optically active chloroalkyl arylketones followed by a chemical cyclization to give the desired heterocycles. Among the various whole cells screened (baker’s yeast, Kluyveromyces marxianus CBS 6556, Saccharomyces cerevisiae CBS 7336, Lactobacillus reuteri DSM 20016), baker’s yeast provided the best yields and the highest enantiomeric ratios (95:5) in the bioreduction of the above ketones. In this respect, valuable chiral non-racemic functionalized oxygen-containing heterocycles (e.g., (S)-styrene oxide, (S)-2-phenyloxetane, (S)-2-phenyltetrahydrofuran), amenable to be further elaborated on, can be smoothly and successfully generated from their prochiral precursors. Studies about pure biocatalysts with mechanistical studies, application in different reactions, and new immobilization methods for improving their stability were reported in five different articles. The article by Su-Yan Wang et al. describes the cloning, expression, purification, and characterization of an N-acetylglucosamine 2-epimerase from Pedobacter heparinus (PhGn2E). For this, several N-acylated glucosamine derivatives were chemically synthesized and used to test the substrate specificity of the enzyme. The mechanism of the enzyme was studied by hydrogen/deuterium NMR. The study at the anomeric hydroxyl group and C-2 position of the substrate in the reaction mixture confirmed the epimerization reaction via ring-opening/enolate formation. Site-directed mutagenesis was also used to confirm the proposed mechanism of this interesting enzyme. The article by Forest H. Andrews et al. studies two enzymes, benzoylformate decarboxylase (BFDC) and pyruvate decarboxylase (PDC), which catalyze the non-oxidative decarboxylation of 2-keto acids with different specificity. BFDC from Pseudomonas putida exhibited very limited activity with pyruvate, whereas the PDCs from S. cerevisiae or from Zymomonas mobilis showed virtually no activity with benzoylformate (phenylglyoxylate). After studies using saturation mutagenesis, the BFDC T377L/A460Y variant was obtained, with 10,000-fold increase in pyruvate/benzoylformate. The change was attributed to an improvement in the Km value for pyruvate and a decrease in the kcat value for benzoylformate. The characterization of the new catalyst was performed, providing context for the observed changes in the specificity. The article by Xin Wang et al. compares two types of biocatalysts to produce D-lysine L-lysine in a cascade process catalyzed by two enzymes: racemase from microorganisms that racemize L-lysine to give D,L-lysine and decarboxylase that can be in cells, permeabilized cells, and the isolated enzyme. The comparison between the different forms demonstrated that the isolated enzyme showed the higher decarboxylase activity. Under optimal conditions, 750.7 mmol/L D-lysine was finally obtained from 1710 mmol/L L-lysine after 1 h of racemization reaction and 0.5 h of decarboxylation reaction. D-lysine yield could reach 48.8% with enantiomeric excess (ee) of 99%. In the article by Rivero and Palomo, lipase from Candida rugosa (CRL) was highly stabilized at alkaline pH in the presence of PEG, which permitted its immobilization for the first time by multipoint covalent attachment on different aldehyde-activated matrices. Different covalent immobilized preparation of the enzyme was successfully obtained. The thermal and solvent stability was highly increased by this treatment, and the novel catalysts showed high regioselectivity in the deprotection of per-O-acetylated nucleosides. The article by Robson Carlos Alnoch et al. describes the protocol and use of a new generation of tailor-made bifunctional supports activated with alkyl groups that allow the immobilization of proteins through the most hydrophobic region of the protein surface and aldehyde groups that allows the covalent immobilization of the previously adsorbed proteins. These supports were especially used in the case of lipase immobilization. The immobilization of a new metagenomic lipase (LipC12) yielded a biocatalyst 3.5-fold more active and 5000-fold more stable than the soluble enzyme. The PEGylated immobilized lipase showed high regioselectivity, producing high yields of the C-3 monodeacetylated product at pH 5.0 and 4 °C. Hybrid catalysts composed of an enzyme and metallic complex are also treated in this Special Issue. The article by Christian Herrero et al. describes the development of the Mn(TpCPP)-Xln10A artificial metalloenzyme, obtained by non-covalent insertion of Mn(III)-meso-tetrakis(p-carboxyphenyl)porphyrin [Mn(TpCPP), 1-Mn] into xylanase 10A from Streptomyces lividans (Xln10A). The complex was found able to catalyze the selective photo-induced oxidation of organic substrates in the presence of [RuII(bpy)3]2+ as a photosensitizer and [CoIII(NH3)5Cl]2+ as a sacrificial electron acceptor, using water as oxygen atom source. The two published reviews describe different subjects with interest in the fields of biocatalysis and mix metallic-biocatalysis, respectively. The review by Anika Scholtissek et al. describes the state-of-the-art regarding ene-reductases from the old yellow enzyme family (OYEs) to catalyze the asymmetric hydrogenation of activated alkenes to produce chiral products with industrial interest. The dependence of OYEs on pyridine nucleotide coenzyme can be avoided by using nicotinamide coenzyme mimetics. In the review, three main classes of OYEs are described and characterized. The review by Yajie Wang and Huimin Zhao highlights some of the recent examples in the past three years that combine transition metal catalysis with enzymatic catalysis. With recent advances in protein engineering, catalyst synthesis, artificial metalloenzymes, and supramolecular assembly, there is great potential to develop more sophisticated tandem chemoenzymatic processes for the synthesis of structurally complex chemicals. In conclusion, these nine publications give an overview of the possibilities of different catalysts, both traditional biocatalysts and hybrids with metals or organometallic complexes to be used in different processes—particularly in synthetic reactions—under very mild reaction conditions.
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Since Langer’s seminal work, polymers have been on every corner of tissue engineering. The roles of bioresorbable polymers, as a scaffold, are not merely structural, providing three-dimensional (3D) homing sites to cells, but also functional at their interface with the cells. The polymeric scaffolds actively act as both biochemical and physical cues for cell behaviors, such as adhesion, growth, proliferation, and differentiation. Polymers and cells could interact further with each other mutually, sensing and responding to the signals from the partner. Technological advances in this direction, including chemical modification of polymer scaffolds, highly cytocompatible hybrid materials/composites, dynamic scaffolds, control of juxtacrine interactions, and 3D bioprinting and microfluidic devices, ensure the advances in polymers as cell scaffolds. The detection and characterization methods for cell-material interactions and cell behaviors have been greatly improved, and new characterization techniques have emerged. Recent years have witnessed a quantum leap of progress in tissue engineering and regenerative medicine, and this edited book illustrates some of the advances in polymers as cell scaffolds.
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Three-dimensional printing is a futuristic technology capable of transforming the ways in which we make components and devices. It is almost certain that this technique will find its niche in the manufacturing sector in the very near future. In view of the growing importance of 3D printing, this book addresses key issues related to emerging science and technology in this area. Detailed and informative articles are presented in relation to a wide variety of materials, including those based on critical engineering metals such as aluminum, magnesium, titanium and composites. Advances in various techniques, such as electron beam melting and selective laser melting are discussed. Of key importance in the area of materials science is the end properties of the materials following processing. Accordingly, the articles presented critically discuss the effects of microstructural features such as porosity, forming defects and the heat treatment induced effects on the mechanical properties. Applications covered in these articles are targeted at the aerospace, automobile, defense and aerospace sectors. Overall, the information presented in this book is of significant importance for academic and industrial-based researchers who wish to inform themselves regarding this upcoming highly promising manufacturing technique.
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This book contains the successful submissions to a Special Issue of Energies on the subject area of “Engineering Fluid Dynamics”. The topic of engineering fluid dynamics includes both experimental as well as computational studies. Of special interest were submissions from the fields of mechanical, chemical, marine, safety, and energy engineering. We welcomed both original research articles as well as review articles. After one year, 22 papers were submitted and 12 were accepted for publication. The average processing time was 65.2 days. The authors had the following geographical distribution: China (four); Italy (two); Korea (one); Germany (one); UK (one); Ireland (one); Australia (one); Sweden (one); Japan (one); Spain (one); Norway (one). Papers covered topics such as heat transfer in shell and helically coiled tube heat exchangers, the multiphase modeling of sprays, flashing flows, as well as mixing in a bubbling fluidized bed. Two papers related to heating ventilation and air condition (HVAC) are included, namely evaporation and condensation in the underfloor space of detached houses and air distribution in a railway vehicle. Three papers dealt with various aspects of pumps and turbines: a performance prediction method for pumps as turbines; noise radiation in a centrifugal pump; periodic fluctuations in energy efficiency in centrifugal pumps; and study of a high-pressure external gear pump. One paper used both laser doppler velocimetry (LDV) and CFD in the study of flow behind a semi-circular step cylinder. Finally, a paper investigated the influence of the equivalence ratio (ER) and feedstock particle size on birch wood gasification.
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Air quality is personal. Its management is highly so. Asthmatic or air-pollutant-sensitive individuals depend on accurate air quality forecasts to help manage their daily activities. However, the adverse effects of poor air quality on public health and visibility extend far beyond the daily time horizon. Pneumonic and cardiac vascular responses of individuals in all age groups can be both acute, episodic and short-term, as well as chronic, accumulative and long-term. Urban haze resulting from stagnant poor air can linger for many days. In this Special Issue, seven papers cover a wide range of air pollution forecasting technology and emission control responses. It is paramount to verify and improve air quality forecast modeling systems constantly by as many quality-assured and cross-calibrated measurements as possible. Improvements from national centers such as the U. S. National Oceanic and Atmospheric Administration’s (NOAA) research arms must produce verification statistics satisfying operational center performance metrics over multiple seasons before implementation is possible. High quality, compact, and mobile monitors are a significant player in air quality and atmospheric composition continuous measurements and are poised to become even more important. Five papers in this issue provide insight on observation technological advances and data assimilation. Air quality monitoring and forecasting sciences necessarily advance in lock-step and improvements for one benefit the other.
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Since Langer’s seminal work, polymers have been on every corner of tissue engineering. The roles of bioresorbable polymers, as a scaffold, are not merely structural, providing three-dimensional (3D) homing sites to cells, but also functional at their interface with the cells. The polymeric scaffolds actively act as both biochemical and physical cues for cell behaviors, such as adhesion, growth, proliferation, and differentiation. Polymers and cells could interact further with each other mutually, sensing and responding to the signals from the partner. Technological advances in this direction, including chemical modification of polymer scaffolds, highly cytocompatible hybrid materials/composites, dynamic scaffolds, control of juxtacrine interactions, and 3D bioprinting and microfluidic devices, ensure the advances in polymers as cell scaffolds. The detection and characterization methods for cell-material interactions and cell behaviors have been greatly improved, and new characterization techniques have emerged. Recent years have witnessed a quantum leap of progress in tissue engineering and regenerative medicine, and this edited book illustrates some of the advances in polymers as cell scaffolds.
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From paintings and food to illness and icebergs, science is happening everywhere. Rather than follow the path of a syllabus or textbook, Andrew Morris takes examples from the science we see every day and uses them as entry points to explain a number of fundamental scientific concepts – from understanding colour to the nature of hormones – in ways that anyone can grasp. While each chapter offers a separate story, they are linked together by their fascinating relevance to our daily lives.
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This Special Issue highlights novel nanocolloids like magnetic nanoparticles, nanomicelles, nanoliposomes, nanocapsules, and nanoclays, stimulating novel interests and ideas in research groups involved in the development of novel nanotools within the different areas of nanomaterials. The publication of original articles contributes to scientific progress in the area of personalized medicine and further stimulates the entering into clinical praxis of such new nanosystems.
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On April 22, 1915, the German military released 150 tons of chlorine gas at Ypres, Belgium. Carried by a long-awaited wind, the chlorine cloud passed within a few minutes through the British and French trenches, leaving behind at least 1,000 dead and 4,000 injured. This chemical attack, which amounted to the first use of a weapon of mass destruction, marks a turning point in world history. The preparation as well as the execution of the gas attack was orchestrated by Fritz Haber, the director of the Kaiser Wilhelm Institute for Physical Chemistry and Electrochemistry in Berlin-Dahlem. During World War I, Haber transformed his research institute into a center for the development of chemical weapons (and of the means of protection against them).
Bretislav Friedrich and Martin Wolf (Fritz Haber Institute of the Max Planck Society, the successor institution of Haber’s institute) together with Dieter Hoffmann, Jürgen Renn, and Florian Schmaltz (Max Planck Institute for the History of Science) organized an international symposium to commemorate the centenary of the infamous chemical attack. The symposium examined crucial facets of chemical warfare from the first research on and deployment of chemical weapons in WWI to the development and use of chemical warfare during the century hence. The focus was on scientific, ethical, legal, and political issues of chemical weapons research and deployment — including the issue of dual use — as well as the ongoing effort to control the possession of chemical weapons and to ultimately achieve their elimination.
The volume consists of papers presented at the symposium and supplemented by additional articles that together cover key aspects of chemical warfare from 22 April 1915 until the summer of 2015.
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This open access book is the proceedings of the 14th International Symposium on Biomineralization (BIOMIN XIV) held in 2017 at Tsukuba. Over the past 45 years, biomineralization research has unveiled details of the characteristics of the nano-structure of various biominerals; the formation mechanism of this nano-structure, including the initial stage of crystallization; and the function of organic matrices in biominerals, and this knowledge has been applied to dental, medical, pharmaceutical, materials, agricultural and environmental sciences and paleontology. As such, biomineralization is an important interdisciplinary research area, and further advances are expected in both fundamental and applied research.
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The Gulf of Mexico is an open and dynamic marine ecosystem rich in natural resources but heavily impacted by human activities, including agricultural, industrial, commercial and coastal development. Nutrients and pollutants from coastal communities and dozens of rivers flow into the Gulf, including material from the Mississippi River watershed, which drains over one third of continental United States. The Gulf of Mexico has been continuously exposed to petroleum hydrocarbons for millions of years from natural oil and gas seeps on the sea floor, and more recently from oil drilling and production activities located in the water near and far from shore. Major accidental oil spills in the Gulf are infrequent; two of the most significant include the Ixtoc I blowout in the Bay of Campeche in 1979 and the Deepwater Horizon Oil Spill in 2010. Unfortunately, baseline assessments of the status of habitats and biota in the Gulf of Mexico before these spills either were not available, or the data had not been systematically compiled in a way that would help scientists assess the potential short-term and long-term effects of such events.
This 2-volume series compiles and summarizes thousands of data sets showing the status of habitats and biota in the Gulf of Mexico before the Deepwater Horizon Oil Spill that began on April 20, 2010. Volume 1 begins with an overview of the following 13 chapters and focuses on the big picture rather than the details of habitat quality and biota.
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This book provides comprehensive research findings related to the environmental monitoring of radiation, levels of radioactive nuclides in various environments, and dose estimation in residents after the Fukushima nuclear power plant accident caused severe environmental contamination with radioactive nuclides. At the beginning of the book, a technical review written by a leading researcher of nuclear reactor technology explains what happened at the power plant. The review is followed by a commentary from a former member of the International Commission on Radiological Protection, providing the reader with easily understandable information about the concept of radiation dosage. In the main part of the book, a series of scientific reports presents valuable data on the radiation surveys of the environment, environmental radioactivity, transfer models and parameters of radioactive nuclides, and dose assessment among residents. These reports present a wide range of findings from the research carried out in a variety of activities by large governmental organizations as well as by small private groups and individuals. The reader thus will find a large collection of valuable and interesting data related to the environmental contamination by radioactive nuclides after the Fukushima accident. Although earlier reports on this issue have been made public, this book is the only publication to fully depict the actual situation by providing comprehensive data obtained by diverse organizations and individuals.
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This open access book focuses on investigating predicting precursor information and key points of rockburst in mining engineering through laboratory experiment, theoretical analysis, numerical simulation and case studies. Understanding the evolution patterns for the microstructure instability of rock is a prerequisite for rockburst prediction. The book provides a guide for readers seeking to understand the evolution patterns for the microstrucure of rock failure, the predicting key point of rock failure and the rockburst predicting model. It will be an essential reference to understand mechanism of rockburst and sheds new light on dynamic disasters prediction. Chapters are carefully developed to cover (1) The evolution patterns for the microstructure instability of rock; (2) Rockburst hazard monitoring and predicting criterion and predicting models. The book addresses the issue with a holistic and systematic approach that investigates the occurrence mechanism of rockburst based on the evolution patterns for the microstructure of rock failure and establishes the predicting model of rockburst.
This book will be of interest to researchers of mining engineering, rock mechanics engineering and safety engineering.
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This book offers a concise, practice-oriented reference-guide to the field of ocean wave energy. The ten chapters highlight the key rules of thumb, address all the main technical engineering aspects and describe in detail all the key aspects to be considered in the techno-economic assessment of wave energy converters. Written in an easy-to-understand style, the book answers questions relevant to readers of different backgrounds, from developers, private and public investors, to students and researchers. It is thereby a valuable resource for both newcomers and experienced practitioners in the wave energy sector.
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The subject of this book relates to protein ligands with particular structural and complexation properties. They are composed of self-assembled molecules, capable of penetrating as a unit into proteins outside the binding site. The ribbon-like supramolecular system only permits the penetration of self-assembled molecules into the protein-body and formation of stable complexes. Supramolecular Congo red and similar compounds fit these requirements. Destabilized protein fragments enable the penetration of such ligands, with susceptibility to supramolecular ligand binding often associated with protein function. As a result, complexation modifies their functional effects. The activity of enzymes is inhibited by arresting them in the complexed state, but “naturally irreversible” complexation as in the case of immune complexation, is enhanced instead. This property offers many attractive possibilities of using supramolecular ligands as described in this book.
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Suzuki–Miyaura cross-coupling remains a powerful tool in organic synthesis for C–C bond formation and has various industrial applications, for example, the synthesis of pharmaceuticals and materials. Intensive research efforts are being made into finding ways of improving and expanding the scope of this process, and the development of more efficient catalytic systems for this extremely important reaction is still a hot research topic of enormous academic and industrial interest. This Special Issue, consisting of four reviews, two communications and six articles, focuses on recent promising research and novel trends in the broad field of Suzuki–Miyaura cross-coupling employing a range of different palladium catalysts. Homogeneous or heterogeneous catalysis in organic or aqueous medium, using conventional conditions or non-conventional techniques such as microwave and ultrasound irradiation, grinding and photo-activated processes as green chemistry approaches, as well as continuous flow technology are included. The catalysts described herein are unsupported metal complexes, catalysts immobilized on solid supports, ligand-free catalytic systems or metal nanoparticles.
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Titanium is a good example of a material that is globally recognized for its outstanding properties, making it desirable for a range of industries. Titanium and its alloys are utilized in a wide range of industries, including aerospace, automotive and high performance leisure equipment. This Special Issue of Metals focusing on titanium contains a range of articles based on research into this fascinating material and its wide range of alloys. For applications that can withstand the high basic cost of titanium it is shown that the unique properties of the material have the potential to provide further performance improvements to existing industries, whilst offering new opportunities to emerging markets.
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Fluid transport in narrow pores is central to the design and optimization of nanoporous materials in industrial applications, such as catalysis, nanofluids, electrochemical batteries, and membrane separation. However, due to the strong potential field in nanopores, conventional models and methods have become inadequate for predicting the transport behavior of molecules confined in the pore space. In addition, the inherent complexity of the pore structure in nanomaterials requires consideration of local or nanoscale transport at the single pore level, and averaging over the macroscale, which further impedes the application and validation of the formulated mechanical models. To solve the problem of fluid transport in narrow nanopores beyond Knudsen limits, experimental characterizations should be combined to molecular simulations in order to probe the fluid movement under realistic conditions. This book provides comprehensive perspectives on the current research in the investigation of fluid transport processes in nanomaterials. The articles from leading scholars in this field are conveniently arranged according to three categories based on the approaches used in the papers: modeling and simulation, nanomaterial manipulation and characterization, and practical application. The 14 contributions not only demonstrate the importance of fluid behavior in different applications but also address the main theories and simulations to model the fluid transport behavior in nanoporous materials. This collection shows that “fluid transport in nanomaterials” remains a versatile and vibrant topic in terms of both theories and applications.
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Micro-extraction techniques in sample preparation are gaining interest among analytical chemists as they comply with green analytical chemistry demands and ensure environmental protection and public safety. Savings in cost and time are considered as valuable benefits by using novel micro-extraction approaches in sample handling. Selectivity, sensitivity and lower detection limits are also included among the performance characteristics required to meet the legislation criteria. The target of this special issue is to present the state of art in microextraction sample preparation techniques. Modern, simple and efficient methods for preconcentration and separation are described for different analytes isolated from various matrices.
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This book on water soluble polymers (WSP) contains contributions that deal with this extremely popular area of scientific investigation in polymer science and engineering, both in academic and industrial environments. The book contents cover a wide variety of topics, starting from polymerization kinetics (emphasis on multicomponent systems), clarification of factor effects (for example, ionic strength, pH, monomer concentration, and how they influence important chain characteristics and properties), mathematical modelling, parameter estimation, and process design, and ending with applications (i.e., using the well characterized polymer molecules to deliver specific desirable properties for specific applications (hydrogels, cosmetics, drug release, flocculation, nanotechnology, enhanced oil recovery, polymer flooding, absorbents, crosslinking, and many others)). This book contains 17 very high quality contributions from author groups that span the globe and represent currently active researchers in the WSP area.
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Polymers aims to compile the current trends and research directions of internationally renowned and successful young polymer scientists in one dedicated Special Issue. The idea for this Special Issue has arisen from the numerous and, above all, brilliant nominations for our 1st Young Investigator Award. It was the easiest-ever choice for us to publicly share the fascinating and thrilling research successes of the nominated scientists with you, our dear peer readers. For this prestigious Special Issue, the journal Polymers will only accept original research papers that have been invited exclusively by the editors. The contributions to this Special Issue will highlight the current state-of-the-art in the fields of polymerization methods, theory/simulation/modeling, new physical phenomena, advances in characterization techniques, and harnessing of self-assembly and biological strategies for producing complex multifunctional structures. Please enjoy reading these high-end research highlights
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The term zeolite is based on Greek words for “to boil” and “stone” and it is already known since more than 250 years. At that time, the Swedish mineralogist A.F. Cronstedt (1722-1765) observed the formation of large amount of steam when heating the material Stilbite pointing to his porous character and adsorption capacity. At present, over 200 different zeolite frameworks have been identified. In general, zeolites are crystalline aluminosilicates with defined micropore structure. Within zeolites, a good number of elements can be isomorphously incorporated and much more elements or their oxides can be hosted by zeolites. Besides their big variety in size of pore mouths, channels, crossings etc. leading also to their designation as molecular sieves and uses in membrane applications, zeolites reveal Brønsted and Lewis acidic properties that can be varied in wide limits as well. Thus, they deserve the name “solid acids”. Zeolites have an immense importance in diverse industrial applications as catalysts and adsorbents, for example in refinery industry, chemical industry, detergent sector or for solar thermal collectors and adsorption refrigeration In this special issue we aim at new developments and recent progress with respect to zeolite-catalyzed chemical reactions, adsorption applications and membrane uses as well as improved syntheses strategies and characterization techniques.
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The summary should be ca. 200 words; this text will present the book in all promotional forms (e.g. flyers). Please describe the book in straightforward and consumer-friendly terms. [Zinc oxide (ZnO) is a wide band gap semiconductor with an energy gap of 3.37 eV at room temperature. It has been used considerably for its catalytic, electrical, optoelectronic, and photochemical properties. ZnO nanomaterials, such as quantum dots, nanorods, and nanowires, have been intensively investigated for their important properties. Many methods have been described in the literature for the production of ZnO nanostructures, such as laser ablation, hydrothermal methods, electrochemical deposition, sol-gel methods, chemical vapour deposition, molecular beam epitaxy, the common thermal evaporation method, and the soft chemical solution method. The present Special Issue is devoted to the synthesis and characterization of ZnO nanostructures with novel technological applications.
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Nowadays, transition metal-oxides can be considered the most investigated materials especially in their nanostructured forms thanks to their intrinsic smart properties and to the positive effects induced by scaling their dimension down to the nanoscale. Among them, ZnO and TiO2 have attracted particular interest mainly because of their multi-functionality applicable in an enormous range of research fields. The present Special Issue – composed by twenty-seven papers, both reviews and research articles - covers the most recent advances in ZnO and TiO2 nanostructures, concerning not only their synthesis and characterization, but also reports of the manner(s) in which their functional and smart properties can be applied in working devices. Applications of such nanostructures can range widely, from biomedical and drug delivery devices to piezoelectric and chemical sensors, and energy harvesting, conversion, and storage devices.
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Miniaturization is a challenge thrown down to analytical chemistry. The replacement of conventional analytical systems by miniaturized alternatives during the last years is noticeable. Specifically, the miniaturization of traditional sample preparation techniques (e.g., solid-phase extraction or solvent extraction) led to the development of environmentally benign analytical methods. This book aims to provide an overview of the challenges and achievements inthe application of the miniaturized sample preparation methods in analytical laboratories. It includes both theoretical and practical aspects of miniaturized sample preparation approaches and hence should be of interest to researchers, students and teachers of analytical and bioanalytical chemistry, environmental sciences and environmental engineering.
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The Special Issue on Crystal Dislocations is intended to provide a unique international forum aimed at covering a broad range of results involving dislocations and their importance in crystal properties and crystal growth. Scientists working in a wide range of disciplines are invited to contribute to this cause.
