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https://www.readbyqxmd.com/read/28437655/peripheral-artery-disease-redox-signaling-oxidative-stress-basic-and-clinical-aspects
#1
REVIEW
Sebastian Steven, Andreas Daiber, Jörn F Dopheide, Thomas Münzel, Christine Espinola-Klein
Reactive oxygen and nitrogen species (ROS and RNS, e.g. H2O2, nitric oxide) confer redox regulation of essential cellular signaling pathways such as cell differentiation, proliferation, migration and apoptosis. At higher concentrations, ROS and RNS lead to oxidative stress and oxidative damage of biomolecules (e.g. via formation of peroxynitrite, fenton chemistry). Peripheral artery disease (PAD) is characterized by severe ischemic conditions in the periphery leading to intermittent claudication and critical limb ischemia (end stage)...
April 13, 2017: Redox Biology
https://www.readbyqxmd.com/read/28437618/state-of-the-art-calculations-of-sublimation-enthalpies-for-selected-molecular-crystals-and-their-computational-uncertainty
#2
Ctirad Červinka, Michal Fulem
A computational methodology for calculation of sublimation enthalpies of molecular crystals from first principles is developed and validated by comparison to critically evaluated literature experimental data. Temperature dependent sublimation enthalpies for a set of selected 22 molecular crystals in their low-temperature phases are calculated. The computational methodology consists in several building blocks based on high level electronic structure methods of quantum chemistry and statistical thermodynamics...
April 24, 2017: Journal of Chemical Theory and Computation
https://www.readbyqxmd.com/read/28437104/redox-active-macrocycles-for-organic-rechargeable-batteries
#3
Dong Jun Kim, Keith R Hermann, Aleksandrs Prokofjevs, Michael T Otley, Cristian Pezzato, Magdalena Owczarek, J Fraser Stoddart
Organic rechargeable batteries, composed of redox-active molecules, are emerging as candidates for the next generation of energy storage materials because of their large specific capacities, cost effectiveness, and the abundance of organic precursors, when compared with conventional lithium-ion batteries. Although redox-active molecules often display multiple redox states, precise control of a molecule's redox potential, leading to a single output voltage in a battery, remains a fundamental challenge in this popular field of research...
April 24, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28437097/total-syntheses-of-vancomycin-related-glycopeptide-antibiotics-and-key-analogues
#4
Akinori Okano, Nicholas A Isley, Dale L Boger
A review of efforts that have provided total syntheses of vancomycin and related glycopeptide antibiotics, their agylcons, and key analogues is provided. It is a tribute to developments in organic chemistry and the field of organic synthesis that not only can molecules of this complexity be prepared today by total synthesis but such efforts can be extended to the preparation of previously inaccessible key analogues that contain deep-seated structural changes. With the increasing prevalence of acquired bacterial resistance to existing classes of antibiotics and with the emergence of vancomycin-resistant pathogens (VRSA and VRE), the studies pave the way for the examination of synthetic analogues rationally designed to not only overcome vancomycin resistance but provide the foundation for the development of even more powerful and durable antibiotics...
April 24, 2017: Chemical Reviews
https://www.readbyqxmd.com/read/28437084/affinity-binding-of-emr2-expressing-cells-by-surface-grafted-chondroitin-sulfate-b
#5
Anouck L S Burzava, Marek Jasieniak, Michaelia P Cockshell, Claudine S Bonder, Frances J Harding, Hans Joerg Griesser, Nicolas H Voelcker
The propensity of glycosaminoglycans to mediate cell-cell and cell-matrix interactions opens the door to capture cells, including circulating blood cells, onto biomaterial substrates. Chondroitin sulfate (CS) -B is of particular interest, since it interacts with the receptor (EGF)-like module-containing mucin-like hormone receptor-like 2 precursor (EMR2) displayed on the surface of leukocytes and endothelial progenitor cells. Herein, CS-B and its isomer CS-A were covalently immobilized onto heptylamine plasma polymer films via three different binding chemistries to develop platform technology for the capture of EMR2 expressing cells onto solid carriers...
April 24, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/28436848/challenging-the-time-complexity-of-exact-subgraph-isomorphism-for-huge-and-dense-graphs-with-vf3
#6
Vincenzo Carletti, Pasquale Foggia, Alessia Saggese, Mario Vento
Graph matching is essential in several fields that use structured information, such as biology, chemistry, social networks, knowledge management, document analysis and others. Except for special classes of graphs, graph matching has in the worst-case an exponential complexity; however, there are algorithms that show an acceptable execution time, as long as the graphs are not too large and not too dense. In this paper we introduce a novel subgraph isomorphism algorithm, VF3, particularly efficient in the challenging case of graphs with thousands of nodes and a high edge density...
April 24, 2017: IEEE Transactions on Pattern Analysis and Machine Intelligence
https://www.readbyqxmd.com/read/28436674/general-dialdehyde-click-chemistry-for-amine-bioconjugation
#7
Sina Elahipanah, Paul J O'Brien, Dmitry Rogozhnikov, Muhammad N Yousaf
The development of methods for conjugating a range of molecules to primary amine functional groups has revolutionized the fields of chemistry, biology, and material science. The primary amine is a key functional group and one of the most important nucleophiles and bases used in all of synthetic chemistry. Therefore, tremendous interest in the synthesis of molecules containing primary amines and strategies to devise chemical reactions to react with primary amines has been at the core of chemical research. In particular, primary amines are a ubiquitous functional group found in biological systems as free amino acids, as key side chain lysines in proteins, and in signaling molecules and metabolites and are also present in many natural product classes...
April 24, 2017: Bioconjugate Chemistry
https://www.readbyqxmd.com/read/28436651/synthesis-of-dicarba-closo-dodecaborane-1-carboxamides
#8
Matthias S Scholz, Lukas M Wingen
Amide bond formation is one of the most important chemical reactions. In peptide and organic chemistry, the application of amide coupling reagents is a routine strategy, but surprisingly not in carborane chemistry. Thus, we now report a fast, safe, and robust protocol to couple amines to m- and p-dicarba-closo-dodecaborane-1-carboxylic acids. The procedure comprises the activation of carboxylic acid with the coupling reagent (1-cyano-2-ethoxy-2-oxoethylidenaminooxy)(dimethylamino)morpholinocarbenium hexafluorophosphate, extraction of the product using the hydrophobic nature of the cluster, and a straightforward chromatographic purification...
April 24, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28436590/identification-of-small-molecules-using-accurate-mass-ms-ms-search
#9
REVIEW
Tobias Kind, Hiroshi Tsugawa, Tomas Cajka, Yan Ma, Zijuan Lai, Sajjan S Mehta, Gert Wohlgemuth, Dinesh Kumar Barupal, Megan R Showalter, Masanori Arita, Oliver Fiehn
Tandem mass spectral library search (MS/MS) is the fastest way to correctly annotate MS/MS spectra from screening small molecules in fields such as environmental analysis, drug screening, lipid analysis, and metabolomics. The confidence in MS/MS-based annotation of chemical structures is impacted by instrumental settings and requirements, data acquisition modes including data-dependent and data-independent methods, library scoring algorithms, as well as post-curation steps. We critically discuss parameters that influence search results, such as mass accuracy, precursor ion isolation width, intensity thresholds, centroiding algorithms, and acquisition speed...
April 24, 2017: Mass Spectrometry Reviews
https://www.readbyqxmd.com/read/28436548/an-open-source-framework-for-analyzing-n-electron-dynamics-i-multideterminantal-wave-functions
#10
Vincent Pohl, Gunter Hermann, Jean Christophe Tremblay
The aim of the present contribution is to provide a framework for analyzing and visualizing the correlated many-electron dynamics of molecular systems, where an explicitly time-dependent electronic wave packet is represented as a linear combination of N-electron wave functions. The central quantity of interest is the electronic flux density, which contains all information about the transient electronic density, the associated phase, and their temporal evolution. It is computed from the associated one-electron operator by reducing the multideterminantal, many-electron wave packet using the Slater-Condon rules...
April 24, 2017: Journal of Computational Chemistry
https://www.readbyqxmd.com/read/28436505/well-defined-functional-mesoporous-silica-polymer-hybrids-prepared-by-an-icar-atrp-technique-integrated-with-bio-inspired-polydopamine-chemistry-for-lithium-isotope-separation
#11
Yuekun Liu, Xuegang Liu, Gang Ye, Yang Song, Fei Liu, Xiaomei Huo, Jing Chen
Mesoporous silica/polymer hybrids with well-preserved mesoporosity were prepared by integrating the initiators for continuous activator regeneration (ICAR) atom transfer radical polymerization (ATRP) technique with the bio-inspired polydopamine (PDA) chemistry. By manipulating the auto-oxidative polymerization of dopamine, uniform PDA layers were deposited on the surfaces and pore walls of ordered mesoporous silicas (OMSs), thereby promoting the immobilization of ATRP initiators. Poly(glycidyl methacrylate) (PGMA) brushes were then grown from the OMSs by using the ICAR ATRP technique...
April 24, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28436497/metal-ion-binding-by-laterally-non-symmetric-macrobicyclic-oxa-aza-cryptands
#12
Parimal K Bharadwaj
Macrobicyclic cryptands incorporating amine groups along with oxygen donors that are laterally non-symmetric constitute an important class of organic compounds. These molecules can form inclusion complexes with different transition and main group metal ions. It is also possible to modify the binding characteristics of these compounds through attachment of different groups. Some of these metal complexes can be useful homogeneous catalysts in different organic transformations. If there are chiral centers present in the cryptands, they can be useful in asymmetric syntheses...
April 24, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28436262/private-philanthropy-and-basic-research-in-mid-twentieth-century-america-the-hickrill-chemical-research-foundation
#13
Leon Gortler, Stephen J Weininger
The Hickrill Chemical Research Foundation, located north of New York City on the estate of its patrons, Sylvan and Ruth Alice Norman Weil, had a short (1948-59) but productive life. Ruth Alice Weil received a Ph.D. in organic chemistry in 1947, directed by William von Eggers Doering of Columbia University. She intended that Hickrill contribute to cancer chemotherapy while providing resources for Doering's more speculative research. Ultimately, Doering's commitment to theoretical organic chemistry set Hickrill's research agenda...
April 24, 2017: Ambix
https://www.readbyqxmd.com/read/28436150/george%C3%A2-a-olah-1927-2017
#14
G K Surya Prakash
George Andrew Olah, Founding Director, Loker Hydrocarbon Research Institute at the University of Southern California, passed away on March 8, 2017. Olah was awarded the Nobel Prize in Chemistry 1994 for his work on the stabilization of carbocations in superacids. In recent years he was highly active in establishing a methanol economy, in which carbon dioxide is converted to methanol for use as a fuel or feedstock.
April 24, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28436149/transgenic-mir156-switchgrass-in-the-field-growth-recalcitrance-and-rust-susceptibility
#15
Holly L Baxter, Mitra Mazarei, Alexandru Dumitrache, Jace Natzke, Miguel Rodriguez, Jiqing Gou, Chunxiang Fu, Robert W Sykes, Geoffrey B Turner, Mark F Davis, Steven Brown, Brian Davison, Zeng-Yu Wang, C Neal Stewart
Sustainable utilization of lignocellulosic perennial grass feedstocks will be enabled by high biomass production and optimized cell wall chemistry for efficient conversion into biofuels. MicroRNAs are regulatory elements that modulate the expression of genes involved in various biological functions in plants, including growth and development. In greenhouse studies, overexpressing a microRNA (miR156) gene in switchgrass had dramatic effects on plant architecture and flowering, which appeared to be driven by transgene expression levels...
April 24, 2017: Plant Biotechnology Journal
https://www.readbyqxmd.com/read/28436126/celebrating-canadian-chemistry
#16
EDITORIAL
Douglas W Stephan, Mark Lautens
"… This issue of Angewandte Chemie commemorates the 100th anniversary of the Canadian Society for Chemistry. It contains contributions from Canadian and German chemists covering a broad and diverse array of subject areas. We are proud to reflect on the accomplishments of the Canadian chemical community and are excited about what the future holds …".
April 24, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28436076/unclicking-the-click-metal-assisted-mechanochemical-cycloreversion-of-triazoles-is-possible
#17
Martin Krupička, Przemyslaw Dopieralski, Dominik Marx
The mechanochemical cycloreversion of 1,2,3-triazole compounds, which serve as unusually stable building blocks in materials and biomolecular chemistry as a result of mild "click chemistry", remains puzzling. We show that the hitherto discussed straight-forward retro-click mechanism of the 1,4-disubstituted isomer, even if Cu(I) catalyzed, can be ruled out in view of more favorable activation free energies of destructive pathways. In stark contrast, the 1,5-regioiomer can undergo cycloreversion under rather mild mechanochemical conditions owing to its favorable response to the external force in conjunction with standard Ru(II) catalysis...
April 24, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28436069/the-eprep-system-a-new-electrophoretic-approach-for-dna-isolation-from-biological-samples
#18
Corinna Kueppers, Sabine Schlappa, Annette Bogdoll, Lothar Breitkopf, Nicole Seip, Thorsten Singer
We present a new free-flow electrophoretic separation system that extends the established concepts of nucleic acid migration in an electric field to a broadly applicable preparative scale. The system comprises a disposable flow tube in which the target nucleic acids are separated from impurities by a balanced combination of electrophoretic migration and counter-streaming electroosmotic flow under the influence of an applied external electric field. Despite the complex theoretical background the introduced electrophoretic technology offers simple hardware setup and handling protocols...
April 24, 2017: Electrophoresis
https://www.readbyqxmd.com/read/28436058/stabilizing-the-mxenes-by-carbon-nanoplating-for-developing-hierarchical-nanohybrids-with-efficient-lithium-storage-and-hydrogen-evolution-capability
#19
Xianhong Wu, Zhiyu Wang, Mengzhou Yu, Luyang Xiu, Jieshan Qiu
The MXenes combining hydrophilic surface, metallic conductivity and rich surface chemistries represent a new family of 2D materials with widespread applications. However, their poor oxygen resistance causes a great loss of electronic properties and surface reactivity, which significantly inhibits the fabrication, the understanding of the chemical nature and full exploitation of the potential of MXene-based materials. Herein we report a facile carbon nanoplating strategy for efficiently stabilizing the MXenes against structural degradation caused by spontaneous oxidation, which provides a material platform for developing MXene-based materials with attractive structure and properties...
April 24, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28435946/faraday-discussions-meeting-catalysis-for-fuels
#20
Nico Fischer, Simon A Kondrat, Mzamo Shozi
Welcome to Africa was the motto when after more than 100 years the flag ship conference series of the Royal Society of Chemistry, the Faraday Discussions was hosted for the first time on the African Continent. Under the fitting topic 'Catalysis for Fuels' over 120 delegates followed the invitation by the conference chair Prof. Graham Hutchings FRS (Cardiff Catalysis Institute), his organizing committee and the co-organizing DST-NRF Centre of Excellence in Catalysis c*change (). In the presentations of 21 invited speakers and 59 posters, cutting edge research in the field of catalysis for fuels, designing new catalysts for synthetic fuels, hydrocarbon conversion in the production of synthetic fuels and novel photocatalysis was presented over the two-day meeting...
April 24, 2017: Chemical Communications: Chem Comm
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