Download or read book Site specific Chemistry of Sulfur containing Amino Acids on Si 111 3 3 Ag written by Hanieh Farkhondeh Borazjani and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The interfacial interactions and film growth mechanisms of sulfur-containing amino acids on Si(111)-√3×√3-Ag are investigated by using x-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM) at room temperature and at elevated temperature under ultrahigh vacuum condition. The complementary density functional theory (DFT) calculations with dispersion correction are used to provide precise modeling of the equilibrium adsorption configurations of biomolecules. Cysteine is found to chemisorb initially at surface defects where its island growth fronts further propagate onto terrace regions exhibiting coral-reef-like nanostructures. The lower-step edges and the antiphase boundaries are found to be the preferred adsorption sites followed by upper-step edges and terrace sites. Chemisorption of interfacial cysteine monolayer occurs through S-H cleavage and S-Ag linkage. The zwitterionic hydrogen bonding governs the intermolecular interactions in the interfacial layer, which further grows to zwitterionic multilayer. Our DFT calculations support the experimental results for chemisorption of single molecules to multimers through S-Ag covalent bonding and intermolecular zwitterionic hydrogen bonding. In addition, Ag bridge sites are found to be the most favourable adsorption sites on the surface terraces. At elevated temperatures, cysteine adspecies are found to transform the highly ordered single-atom-thick Si(111)-√3×√3-Ag overlayer into Ag agglomerates of nanometer sizes. This phenomenon offers an interesting approach to converting monoatomic silver silicide layers to silver nanoclusters and quantum dots for chemical sensing and catalysis applications. Methionine, on the other hand, does not chemisorb on Si(111)-√3×√3-Ag due to the termination of its sulfur atom by a methyl group in its methylthio methylene side chain. A minority of methionine adspecies are found to chemisorb through a dehydrogenated amino group most likely at defect sites, step edges and antiphase boundaries. Self-assembled one-dimensional molecular wires are observed at room temperature and at lower temperatures in our variable-temperature STM study, while the chemical state of these molecular wires is found to be zwitterionic by XPS. Our large-scale DFT calculations further support the zwitterionic dimer row structures of the molecular wires. To demonstrate the molecular size effect, the adsorption mechanism of glycine on Si(111)-√3×√3-Ag is also studied. All three amino acids appear to induce metallic Ag 3d features at elevated temperature, indicating the formation of metallic agglomerates. The Si(111)-√3×√3-Ag surface offers a unique platform for developing not only self-assembled molecular nanostructures but also metal nanoclusters and agglomerates for potential applications in catalysis. The Si(111)-√3×√3-Ag surface contains a number of defects, notably step edges and antiphase boundaries, that could significantly affect the adsorption and other surface properties. Detailed understanding of the relations between their structural configurations and these surface properties is of fundamental interest to further unraveling the many unique processes found for this intricate surface. Using first-principle quantum mechanical calculations based on DFT, the equilibrium geometries of the step edge and antiphase boundary are calculated and found to exhibit a one-dimensional chain of Ag trimers on both types of defect sites. Unlike the monolayer coverage in the terrace regions, the Ag:Si stoichiometric ratio is found to be 4:3 at the step edge. This ratio is calculated to be 1:1 for the antiphase boundary (and for the terrace). The total densities of states calculated for the step edge, antiphase boundary, and terrace models exhibit surface states near the Fermi level. The mid-gap state found for the step edge appears to have a more intense density of state and to locate closer to the Fermi level. The corresponding calculation of partial densities of states reveals different contributions of Ag and Si atoms at defect sites. Mid-gap states are known to improve the optical properties of materials such as photon absorption and transfer. As the Si(111)-√3×√3-Ag surface defects promote the mid-gap states and considering their adsorption to be the most favourable, they are expected to play a crucial role in designing applications in (photo) catalysis and chemical sensing.
Download or read book Directory of Graduate Research written by American Chemical Society. Committee on Professional Training and published by . This book was released on 2005 with total page 1932 pages. Available in PDF, EPUB and Kindle. Book excerpt: Faculties, publications and doctoral theses in departments or divisions of chemistry, chemical engineering, biochemistry and pharmaceutical and/or medicinal chemistry at universities in the United States and Canada.
Download or read book Journal written by American Chemical Society and published by . This book was released on 2004 with total page 1042 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Metabolic Therapeutic Aspects of Amino Acids in Clinical Nutrition written by Luc A. Cynober and published by CRC Press. This book was released on 2003-11-13 with total page 778 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first edition of this innovative book brought a new perspective to the metabolic and therapeutic aspects of amino acids in clinical nutrition. Since its publication, a number of very important advances have been made in the field and interesting new findings have emerged. Until now, no reference has fully explored the promising new developments
Download or read book Biological Agricultural Index written by and published by . This book was released on 1975 with total page 2354 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Book of Abstracts written by and published by . This book was released on 2000 with total page 778 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Index Medicus written by and published by . This book was released on 2004 with total page 2388 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vols. for 1963- include as pt. 2 of the Jan. issue: Medical subject headings.
Download or read book Activity Based Protein Profiling written by Benjamin F. Cravatt and published by Springer. This book was released on 2019-01-25 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume provides a collection of contemporary perspectives on using activity-based protein profiling (ABPP) for biological discoveries in protein science, microbiology, and immunology. A common theme throughout is the special utility of ABPP to interrogate protein function and small-molecule interactions on a global scale in native biological systems. Each chapter showcases distinct advantages of ABPP applied to diverse protein classes and biological systems. As such, the book offers readers valuable insights into the basic principles of ABPP technology and how to apply this approach to biological questions ranging from the study of post-translational modifications to targeting bacterial effectors in host-pathogen interactions.
Download or read book March s Advanced Organic Chemistry written by Michael B. Smith and published by John Wiley & Sons. This book was released on 2007-01-29 with total page 2379 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Sixth Edition of a classic in organic chemistry continues its tradition of excellence Now in its sixth edition, March's Advanced Organic Chemistry remains the gold standard in organic chemistry. Throughout its six editions, students and chemists from around the world have relied on it as an essential resource for planning and executing synthetic reactions. The Sixth Edition brings the text completely current with the most recent organic reactions. In addition, the references have been updated to enable readers to find the latest primary and review literature with ease. New features include: More than 25,000 references to the literature to facilitate further research Revised mechanisms, where required, that explain concepts in clear modern terms Revisions and updates to each chapter to bring them all fully up to date with the latest reactions and discoveries A revised Appendix B to facilitate correlating chapter sections with synthetic transformations
Download or read book Fine Tuning of RNA Functions by Modification and Editing written by Henri Grosjean and published by Springer. This book was released on 2005-05-11 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Naturally occurring RNA always contains numerous biochemically altered nucleotides. They are formed by enzymatic modification of the primary transcripts during the complex RNA maturation process designated RNA modification. A large number of enzymes catalyzing the formation of these modified nucleosides or converting one canonical base into another at the posttranscriptional level have been studied for many years, but only recently have systematic and comparative studies begun. The functions of individual enzymes and/or the modified/edited nucleosides in RNA, however, have remained largely ignored. This book provides advance information on RNA modification, including the associated editing machinery, while offering the reader some perspective on the significance of such modifications in fine-tuning the structure and functions of mature RNA molecules and hence the ability to influence the efficiency and accuracy of genetic expression. Outstanding scientists who are actively working on RNA modification/editing processes have provided up-to-date information on these intriguing cellular processes that have been generated over the course of millions of years in all living organisms. Each review has been written and illustrated for a large audience of readers, not only specialists in the field, but also for advanced students or researchers who want to learn more about recent progress in RNA modification and editing.
Download or read book Applied Science Technology Index written by and published by . This book was released on 1997 with total page 2948 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monthly Index of Russian Accessions written by Library of Congress. Processing Department and published by . This book was released on 1965 with total page 1744 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Non Natural Amino Acids written by and published by Academic Press. This book was released on 2009-07-24 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: By combining the tools of organic chemistry with those of physical biochemistry and cell biology, Non-Natural Amino Acids aims to provide fundamental insights into how proteins work within the context of complex biological systems of biomedical interest. The critically acclaimed laboratory standard for 40 years, Methods in Enzymology is one of the most highly respected publications in the field of biochemistry. Since 1955, each volume has been eagerly awaited, frequently consulted, and praised by researchers and reviewers alike. With more than 400 volumes published, each Methods in Enzymology volume presents material that is relevant in today's labs -- truly an essential publication for researchers in all fields of life sciences. - Demonstrates how the tools and principles of chemistry combined with the molecules and processes of living cells can be combined to create molecules with new properties and functions found neither in nature nor in the test tube - Presents new insights into the molecular mechanisms of complex biological and chemical systems that can be gained by studying the structure and function of non-natural molecules - Provides a "one-stop shop" for tried and tested essential techniques, eliminating the need to wade through untested or unreliable methods
Download or read book Cumulated Index Medicus written by and published by . This book was released on 1993 with total page 1356 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sulfur Chemistry written by Xuefeng Jiang and published by Springer Nature. This book was released on 2019-08-28 with total page 475 pages. Available in PDF, EPUB and Kindle. Book excerpt: The series Topics in Current Chemistry Collections presents critical reviews from the journal Topics in Current Chemistry organized in topical volumes. The scope of coverage is all areas of chemical science including the interfaces with related disciplines such as biology, medicine and materials science. The goal of each thematic volume is to give the non-specialist reader, whether in academia or industry, a comprehensive insight into an area where new research is emerging which is of interest to a larger scientific audience. Each review within the volume critically surveys one aspect of that topic and places it within the context of the volume as a whole. The most significant developments of the last 5 to 10 years are presented using selected examples to illustrate the principles discussed. The coverage is not intended to be an exhaustive summary of the field or include large quantities of data, but should rather be conceptual, concentrating on the methodological thinking that will allow the non-specialist reader to understand the information presented. Contributions also offer an outlook on potential future developments in the field.
Download or read book Monthly Index of Russian Accessions written by Library of Congress. Processing Dept and published by . This book was released on 1965-10 with total page 1324 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Principles of Chemical Nomenclature written by G. J. Leigh and published by Royal Society of Chemistry. This book was released on 2011 with total page 271 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aimed at pre-university and undergraduate students, this volume surveys the current IUPAC nomenclature recommendations in organic, inorganic and macromolecular chemistry.
