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Organic chemistry

Mingxue Wu, Gang Chen, Jiutong Ma, Ping Liu, Qiong Jia
Covalent organic frameworks (COFs) are an emerging class of porous organic frameworks with diverse promising applications. Herein, we presented the first example of cross-linked hydrazone COFs (cross-linked COFs) coating via thiol-ene click chemistry for solid phase microextraction (SPME). Strong covalent bonds and interlayer of the prepared networks ensured the adsorption capacity and durability of the novel SPME fiber. π-π conjugated structure existed because of abundant phenyl rings and -C=N groups in the cross-lined COFs...
December 1, 2016: Talanta
Tao Peng, Howard C Hang
Over the past years, fluorescent proteins (e.g., green fluorescent proteins) have been widely utilized to visualize recombinant protein expression and localization in live cells. Although powerful, fluorescent protein tags are limited by their relatively large sizes and potential perturbation to protein function. Alternatively, site-specific labeling of proteins with small-molecule organic fluorophores using bioorthogonal chemistry may provide a more precise and less perturbing method. This approach involves site-specific incorporation of unnatural amino acids (UAAs) into proteins via genetic code expansion, followed by bioorthogonal chemical labeling with small organic fluorophores in living cells...
October 21, 2016: Journal of the American Chemical Society
Kyle D Custard, Kerri A Pratt, Siyuan Wang, Paul B Shepson
During springtime, unique halogen chemistry involving chlorine and bromine atoms controls the prevalence of volatile organic compounds, ozone, and mercury in the Arctic lower troposphere. In situ measurements of the chlorine monoxide radical (ClO) and its precursor Cl2, along with BrO and Br2, were conducted using chemical ionization mass spectrometry (CIMS) during the BRomine, Ozone, and Mercury EXperiment (BROMEX) near Barrow, Alaska in March 2012. To our knowledge, these data represent the first ClO measurements made using CIMS...
October 21, 2016: Environmental Science & Technology
Purnandhu Bose, Pradip K Sukul, Omar M Yaghi, Kentaro Tashiro
We demonstrate a method for the synthesis of a water-soluble multimetallic peptidic array containing a predetermined sequence of metal centers such as Ru(II), Pt(II), and Rh(III). The compound, named as a water-soluble metal-organic complex array (WSMOCA), is obtained through 1) the conventional solution-chemistry-based preparation of the corresponding metal complex monomers having a 9-fluorenylmethyloxycarbonyl (Fmoc)-protected amino acid moiety and 2) their sequential coupling together with other water-soluble organic building units on the surface-functionalized polymeric resin by following the procedures originally developed for the solid-phase synthesis of polypeptides, with proper modifications...
October 8, 2016: Journal of Visualized Experiments: JoVE
R Kelman Wieder, Melanie A Vile, Kimberli D Scott, Cara M Albright, Kelly McMillen, Dale H Vitt, Mark Fenn
Oil extraction and development activities in the Athabasca Oil Sands Region of northern Alberta, Canada release NOx, SOx, and NHx to the atmosphere, ultimately resulting in increasing N and S inputs to surrounding ecosystems through atmospheric deposition. Peatlands are a major feature of the northern Alberta landscape, with bogs covering 6-10% of the land area, and fens covering 21-53%. Bulk deposition of NH4+-N, NO3--N, total inorganic N (TIN), and SO42--S, was quantified using ion exchange resin collectors deployed at 23 locations, over 1-6 years, reveal maximum N and S deposition of 9...
October 21, 2016: Environmental Science & Technology
Joshua Giltinan, Eric Diller, Metin Sitti
At the sub-millimeter scale, capillary forces enable robust and reversible adhesion between biological organisms and varied substrates. Current human-engineered mobile untethered micromanipulation systems rely on forces which scale poorly or utilize gripper-part designs that promote manipulation. Capillary forces, alternatively, are dependent upon the surface chemistry (which is scale independent) and contact perimeter, which conforms to the part surface. We report a mobile capillary microgripper that is able to pick and place parts of various materials and geometries, and is thus ideal for microassembly tasks that cannot be accomplished by large tethered manipulators...
October 21, 2016: Lab on a Chip
Alexander N Shikov, Olga N Pozharitskaya, Valery G Makarov
PURPOSE: Aralia elata var. mandshurica (Rupr. & Maxim.) J.Wen syn. A. mandshurica Rupr. & Maxim is evaluated for its medicinal application. The aim of this study is to analyze pharmacological studies on A. elata var. mandshurica published until December 2015. METHODS: The information regarding the chemistry, safety, effectiveness, and pharmacological and clinical effects of A. elata was systematically collected from the scientific literature through library catalogs; online services such as E-library...
November 15, 2016: Phytomedicine: International Journal of Phytotherapy and Phytopharmacology
Jin-Long Pan, Quan-Zhe Li, Ting-Yu Zhang, Si-Hua Hou, Jun-Cheng Kang, Shu-Yu Zhang
An efficient and convenient method has been developed to achieve direct silylation of unactivated remote primary or secondary C(sp(3))-H bonds to form C-Si bonds with hexamethyldisilane (HMDS). This method highlights the emerging strategy to transform unactivated methyl or methylene into versatile functional groups in organic synthesis and provides a new method to construct functionalized C-Si bonds for synthetic chemistry.
October 20, 2016: Chemical Communications: Chem Comm
Vilwanathan Ravikumar, Renu Sankar
Nanotechnology is a comparatively new branch of science that includes harnessing the unique properties of particles that are nanometers in scale. Nanoparticles can be tailored in a precise fashion where their size, composition, and surface chemistry can be carefully controlled. The nanoprecipitation is a simple, powerful, and low-energy requiring technique, commonly used for the preparation of defined nanoparticles. Histone deacetylase inhibitor Vorinostat-loaded Poly D, L-lactide-co-glycolide (PLGA) polymeric nanoparticles were prepared by the nanoprecipitation technique...
2017: Methods in Molecular Biology
Sara A Buckman, Tamara Krekel, Anouk E Muller, John E Mazuski
The treatment of complicated intra-abdominal infections (cIAI) is increasingly challenging due to increased resistance of Gram-negative organisms. These multidrug resistant organisms lead to an increase in morbidity and mortality. This has led to renewed interest in use of older β-lactam antibiotics in combination with newer β-lactamase inhibitors. Ceftazidime-avibactam is one of the newest such combination antibiotics, which has been released for treatment of complicated intra-abdominal infections in combination with metronidazole...
October 19, 2016: Expert Opinion on Pharmacotherapy
Noor Asidah Mohamed, Richard T Bradshaw, Jonathan W Essex
The effects of electronic polarization in biomolecular interactions will differ depending on the local dielectric constant of the environment, such as in solvent, DNA, proteins, and membranes. Here the performance of the AMOEBA polarizable force field is evaluated under nonaqueous conditions by calculating the solvation free energies of small molecules in four common organic solvents. Results are compared with experimental data and equivalent simulations performed with the GAFF pairwise-additive force field...
October 19, 2016: Journal of Computational Chemistry
Carol Stewart, Nick D Kim, David M Johnston, Mostafa Nayyerloo
The greater Wellington region, New Zealand, is highly vulnerable to large earthquakes because it is cut by active faults. Bulk water supply pipelines cross the Wellington Fault at several different locations, and there is considerable concern about severe disruption of the provision of reticulated water supplies to households and businesses in the aftermath of a large earthquake. A number of policy initiatives have been launched encouraging householders to install rainwater tanks to increase post-disaster resilience...
October 15, 2016: International Journal of Environmental Research and Public Health
Inge Werner, Annette Aldrich, Benjamin Becker, Dennis Becker, Markus Brinkmann, Michael Burkhardt, Norbert Caspers, Sophie Campiche, Nathalie Chèvre, Rolf-Alexander Düring, Beate I Escher, Fabian Fischer, Sabrina Giebner, Katharina Heye, Henner Hollert, Marion Junghans, Cornelia Kienle, Katja Knauer, Muris Korkaric, Veronika Märkl, Jane Muncke, Jörg Oehlmann, Georg Reifferscheid, Daniel Rensch, Andreas Schäffer, Sabrina Schiwy, Simon Schwarz, Helmut Segner, Eszter Simon, Rita Triebskorn, Etiënne L M Vermeirssen, Thomas Wintgens, Markus Zennegg
This report provides a brief review of the 20th annual meeting of the German Language Branch of the Society of Environmental Toxicology and Chemistry (SETAC GLB) held from September 7th to 10th 2015 at ETH (Swiss Technical University) in Zurich, Switzerland. The event was chaired by Inge Werner, Director of the Swiss Centre for Applied Ecotoxicology (Ecotox Centre) Eawag-EPFL, and organized by a team from Ecotox Centre, Eawag, Federal Office of the Environment, Federal Office of Agriculture, and Mesocosm GmbH (Germany)...
2016: Environmental Sciences Europe
John F Obrycki, Kirk G Scheckel, Nicholas T Basta
Lead (Pb) contaminated soils are a potential exposure hazard to the public. Amending soils with phosphorus (P) may reduce Pb soil hazards. Soil from Cleveland, OH containing 726 ± 14 mg Pb kg(-1) was amended in a laboratory study with bone meal and triple super phosphate (TSP) at 5:1 P:Pb molar ratios. Soil was acidified, neturalized and re-acidified to encourage Pb phosphate formation. PRSTM-probes were used to evaluate changes in soil solution chemistry. Soil acidification did not decrease in vitro bioaccessible (IVBA) Pb using either a pH 1...
October 14, 2016: Environmental Pollution
Carla Ferreri, Bernard T Golding, Ullrich Jahn, Jean-Luc Ravanat
The COST Action CM1201 "Biomimetic Radical Chemistry" has been active since December 2012 for four years, developing research topics organized into four working groups: WG1 - Radical Enzymes, WG2 - Models of DNA damage and consequences, WG3 - Membrane stress, signalling and defences, WG4 - Bio-inspired synthetic strategies. International collaborations have been established among the participating 80 research groups with brilliant interdisciplinary achievements. Free radical research with a biomimetic approach has been realized in the COST Action and are summarized in this overview by the four WG leaders...
October 17, 2016: Free Radical Research
James McDonagh, David S Palmer, Tanja Van Mourik, John B O Mitchell
We compare a range of computational methods for the prediction of sublimation thermodynamics (enthalpy, entropy and free energy of sublimation). These include a model from theoretical chemistry that utilizes crystal lattice energy minimization (with the DMACRYS program) and QSPR models generated by both machine learning (Random Forest and Support Vector Machines) and regression (Partial Least Squares) methods. Using these methods we investigate the predictability of the enthalpy, entropy and free energy of sublimation, with consideration of whether such a method may be able to improve solubility prediction schemes...
October 17, 2016: Journal of Chemical Information and Modeling
Dogan Erbahar, Toma Susi, Xavier Rocquefelte, Carla Bittencourt, Mattia Scardamaglia, Peter Blaha, Peter Guttmann, Georgios Rotas, Nikos Tagmatarchis, Xiaohui Zhu, Adam P Hitchcock, Chris P Ewels
C60 fullerene crystals may serve as important catalysts for interstellar organic chemistry. To explore this possibility, the electronic structures of free-standing powders of C60 and (C59N)2 azafullerenes are characterized using X-ray microscopy with near-edge X-ray adsorption fine structure (NEXAFS) spectroscopy, closely coupled with density functional theory (DFT) calculations. This is supported with X-ray photoelectron spectroscopy (XPS) measurements and associated core-level shift DFT calculations. We compare the oxygen 1s spectra from oxygen impurities in C60 and C59N, and calculate a range of possible oxidized and hydroxylated structures and associated formation barriers...
October 17, 2016: Scientific Reports
A L Pilo, Z Peng, S A McLuckey
Tandem mass spectrometry is a powerful approach for the analysis of peptides and proteins due to the primary structural information inherent in the observed products. The fragmentation of peptides and proteins depends heavily on the sequence and ion type of the species of interest. In this perspective special feature article, Scott McLuckey and co-authors show that peptides and proteins containing dehydroalanine, a nonproteinogenic amino acid with an unsaturated side-chain, undergo enhanced cleavage of the N-Cα bond of the dehydroalanine residue to generate c- and z-ions...
October 2016: Journal of Mass Spectrometry: JMS
Mengzhe Guo, Dengyang Yin, Jie Han, Cheng Guo, Xiao Li, Liyan Zhang, Yan Du, Haibo Wang, Daoquan Tang
RATIONALE: Mass spectrometry has been developed as one of the common tools for the analysis of the organometallic systems in the gas phase over decades. The study of the fragmentation of organics-metal complexes has attracted much attention since the interesting dissociation pathways exhibited by these compounds are usually different from the protonated analogues. METHODS: In this work, iohexol complexed with different dications such as Mg(2+) , Cu(2+) , and Zn(2+) have been investigated by ESI tandem mass spectrometry...
October 17, 2016: Rapid Communications in Mass Spectrometry: RCM
Sarwar Beg, Mahfoozur Rahman, Atul Jain, Sumant Saini, Patrick Midoux, Chantal Pichon, Farhan Jalees Ahmad, Sohail Akhter
Metal organic frameworks (MOFs), porous hybrid polymer-metal composites at the nanoscale, are recent innovations in the field of chemistry; they are novel polymeric materials with diverse biomedical applications. MOFs are nanoporous materials, consisting of metal ions linked together by organic bridging ligands. The unique physical and chemical characteristics of MOFs have attracted wider attention from the scientific community, exploring their utility in the field of material science, biology, nanotechnology and drug delivery...
October 11, 2016: Drug Discovery Today
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