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https://www.readbyqxmd.com/read/28098833/role-of-electron-driven-proton-transfer-processes-in-the-ultrafast-deactivation-of-photoexcited-anionic-8-oxoguanine-adenine-and-8-oxoguanine-cytosine-base-pairs
#1
Xiuxiu Wu, Tolga N V Karsili, Wolfgang Domcke
It has been reported that 8-oxo-7,8-dihydro-guanosine (8-oxo-G), which is the main product of oxidative damage of DNA, can repair cyclobutane pyrimidine dimer (CPD) lesions when incorporated into DNA or RNA strands in proximity to such lesions. It has therefore been suggested that the 8-oxo-G nucleoside may have been a primordial precursor of present-day flavins in DNA or RNA repair. Because the electron transfer leading to the splitting of a thymine-thymine pair in a CPD lesion occurs in the photoexcited state, a reasonably long excited-state lifetime of 8-oxo-G is required...
January 14, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28098465/rejection-of-commonly-used-electrolyte-in-asymmetric-flow-field-flow-fractionation-effects-of-membrane-molecular-weight-cut-off-size-fluid-dynamics-and-valence-of-electrolytes
#2
Thilak K Mudalige, Haiou Qu, Sean W Linder
Asymmetric flow field flow fractionation (AF4) is an efficient size based separation technique for the characterization of submicron size particulates. In AF4, membranes having various molecular weight cut-off sizes are used as a barrier to retain particles while allowing carrier fluid containing electrolytes to permeate. Here, we hypothesized that electrolyte rejection by the barrier membrane lead to the accumulation of the electrolytes in the channel during operation. Electrolyte accumulation can cause various adverse effects which can lead to membrane fouling...
January 18, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28098460/sulfate-mediated-end-to-end-assembly-of-gold-nanorods
#3
Seyyed Mohammad Hossein Abtahi, Nathan D Burrows, Fred A Idesis, Catherine J Murphy, Navid B Saleh, Peter J Vikesland
There is interest in the controlled aggregation of gold nanorods (GNRs) for the production of extended nanoassemblies. Prior studies have relied upon chemical modification of the GNR surface to achieve a desired final aggregate structure. Herein, we illustrate that control of electrolyte composition can facilitate end-to-end assembly of cetyltrimethylammonium bromide (CTAB) coated GNRs. By adjusting either the sulfate anion concentration or the exposure time it is possible to connect GNRs in chain-like assemblies...
January 18, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28098404/esi-activity-of-br-bf4-clo4-and-bph4-anions-in-the-presence-of-li-and-nbu4-counter-ions
#4
Konrad Koszinowski, Friederike Lissy
To improve our understanding of the electrospray-ionization (ESI) process, we have subjected equimolar mixtures of salts A(+) X(-) (A(+)  = Li(+) , NBu4(+) ; X(-)  = Br(-) , ClO4(-) , BF4(-) , BPh4(-) ) in different solvents (CH3 CN, tetrahydrofuran, CH3 OH, H2 O) to negative-ion mode ESI and analyzed the relative ESI activity of the different anionic model analytes. The ESI activity of the large and hydrophobic BPh4(-) ion greatly exceeds that of the smaller and more hydrophilic anions Br(-) , ClO4(-) , and BF4(-) , which we ascribe to its higher surface activity...
January 18, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28098402/anion-%C3%AF-interactions-in-flavoproteins-involve-a-substantial-charge-transfer-component
#5
Jiri Kozelka, Yevgen Yurenko, Sophia Bazzi, Radek Marek
Anion-π interactions have been shown to stabilize flavoproteins and to regulate the redox potential of the flavin cofactor. They are commonly attributed to electrostatic forces. Here we show that anion-flavin interactions have a substantial charge-transfer component. Our conclusion emanates from a multiapproach theoretical analysis and is backed by previously reported observations of absorption bands, originating from charge transfer between oxidized flavin and proximate cystein thiolate groups. This partial covalency of anion-flavin contacts renders classical simulations of flavoproteins questionable...
January 18, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28098357/partial-purification-characterization-and-thermal-inactivation-kinetics-of-peroxidase-and-polyphenol-oxidase-isolated-from-kalipatti-sapota-manilkara-zapota
#6
Vishwasrao Chandrahas, Chakraborty Snehasis, Ananthanarayan Laxmi
BACKGROUND: The extraction, purification, and characterization of peroxidase (POD) and polyphenol oxidase (PPO) were studied for Kalipatti sapota fruit. The crude enzyme extract was partially purified by ammonium sulfate precipitation followed by BioGel P100 size exclusion and Unosphere Q anion-exchange chromatography. RESULTS: Molecular weights of 20 kDa (POD) and 24 kDa (PPO) were indicated by SDS-PAGE. A single band was observed on SDS-PAGE with a fold purity of 10...
January 18, 2017: Journal of the Science of Food and Agriculture
https://www.readbyqxmd.com/read/28098324/ionic-screening-and-dissociation-are-crucial-for-understanding-chemical-self-propulsion-in-polar-solvents
#7
Aidan T Brown, Wilson C K Poon, Christian Holm, Joost de Graaf
Polar solvents like water support the bulk dissociation of themselves and their solutes into ions, and the re-association of these ions into neutral molecules in a dynamic equilibrium, e.g., H2O2 ⇌ H(+) + HO2(-). Using continuum theory, we study the influence of these association-dissociation reactions on the self-propulsion of colloids driven by surface chemical reactions (chemical swimmers). We find that association-dissociation reactions should have a strong influence on swimmers' behaviour, and therefore should be included in future modelling...
January 18, 2017: Soft Matter
https://www.readbyqxmd.com/read/28098316/a-family-of-mechanically-adaptive-supramolecular-graphene-oxide-poly-ethylenimine-hydrogels-from-aqueous-assembly
#8
Chao Wang, Yipin Duan, Nicole S Zacharia, Bryan D Vogt
Composite hydrogels containing graphene oxide (GO) offer advantageous mechanical properties, but tuning these properties generally requires the synthesis of new hydrogels or if the hydrogel is thermally responsive, utilization of a chemistry determined temperature window. Here, we demonstrate a simple route to generate a family of GO-based hydrogels from aqueous solution based assembly of GO with polycationic poly(ethylenimine), PEI, without any secondary chemical crosslinking. Tuning the ratio of GO : PEI during the assembly produces a family of hydrogels that responds to mechanical compression by irreversibly altering their equilibrium water content and mechanical properties in a controllable manner...
January 18, 2017: Soft Matter
https://www.readbyqxmd.com/read/28098307/a-ratiometric-fluorescence-probe-for-imaging-sulfur-dioxide-derivatives-in-the-mitochondria-of-living-cells
#9
Yongfei Wang, Qingtao Meng, Run Zhang, Hongmin Jia, Xuehu Zhang, Zhiqiang Zhang
Although sulfur dioxide (SO2) plays an essential role in several physiological processes, monitoring of intracellular SO2 at subcellular levels remains challenging due to the lack of rapid and sensitive methods for its quantification in a 100% aqueous solution. Herein, a new hemicyanine dyes-based fluorescence probe, NBD-Id, was designed and synthesized for the detection of SO2 derivatives in pure aqueous solution and living cells. By virtue of a specific 1,4-addition reaction of SO3(2-)HSO3(-) and the polymethine chain of hemicyanine, significant changes in the absorption and fluorescence emission spectra were observed in less than 20 seconds...
January 18, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28098290/in-situ-ligand-exchange-mediated-0d-1d-transformation-of-a-polyoxovanadate
#10
M Wendt, P Polzin, J van Leusen, C Näther, P Kögerler, W Bensch
The antimonato-polyoxovanadate {Ni(II)(en)3}3[VSbO42(H2O)]·ca.15H2O was utilized as a synthon for the solvothermal in situ generation of the new compound {Ni(II)(phen)3}2[{Ni(II)(en)2}VSbO42(H2O)]·19H2O, a rearrangement induced by ligand metathesis. While in the precursor structure cations and anions are isolated, the solid-state structure of the product is characterized by 1D chains consisting of alternating [V15Sb6O42(H2O)](6-) cluster shells and [Ni(en)2](2+) units covalently linked to neighboring clusters via terminal oxygen atoms...
January 18, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28098280/single-lithium-ion-conducting-solid-polymer-electrolytes-advances-and-perspectives
#11
REVIEW
Heng Zhang, Chunmei Li, Michal Piszcz, Estibaliz Coya, Teofilo Rojo, Lide M Rodriguez-Martinez, Michel Armand, Zhibin Zhou
Electrochemical energy storage is one of the main societal challenges to humankind in this century. The performances of classical Li-ion batteries (LIBs) with non-aqueous liquid electrolytes have made great advances in the past two decades, but the intrinsic instability of liquid electrolytes results in safety issues, and the energy density of the state-of-the-art LIBs cannot satisfy the practical requirement. Therefore, rechargeable lithium metal batteries (LMBs) have been intensively investigated considering the high theoretical capacity of lithium metal and its low negative potential...
January 18, 2017: Chemical Society Reviews
https://www.readbyqxmd.com/read/28098271/a-two-channel-responsive-fluorescent-probe-with-aie-characteristics-and-its-application-for-selective-imaging-of-superoxide-anions-in-living-cells
#12
Xiaoying Gao, Guangxue Feng, Purnima Naresh Manghnani, Fang Hu, Nan Jiang, Jianzhao Liu, Bin Liu, Jing Zhi Sun, Ben Zhong Tang
A two-channel responsive and AIE-active fluorescent probe was developed to selectively detect superoxide anions in living cells, which can be used to track the endogenous superoxide anion level when cells undergo apoptosis and inflammation.
January 18, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28097910/purification-and-biochemical-characterization-of-a-novel-thermostable-serine-alkaline-protease-from-aeribacillus-pallidus-c10-a-potential-additive-for-detergents
#13
Vildan Yildirim, Mustafa Ozkan Baltaci, Ilknur Ozgencli, Melda Sisecioglu, Ahmet Adiguzel, Gulsah Adiguzel
An extracellular thermostable alkaline serine protease enzyme from Aeribacillus pallidus C10 (GenBank No: KC333049), was purified 4.85 and 17. 32-fold with a yield of 26.9 and 19.56%, respectively, through DE52 anion exchange and Probond affinity chromatography. The molecular mass of the enzyme was determined through sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), with approximately 38.35 kDa. The enzyme exhibited optimum activity at pH 9 and at temperature 60 °C. It was determined that the enzyme had remained stable at the range of pH 7...
December 2017: Journal of Enzyme Inhibition and Medicinal Chemistry
https://www.readbyqxmd.com/read/28097795/impaired-n-linked-glycosylation-of-uptake-and-efflux-transporters-in-human-nonalcoholic-fatty-liver-disease
#14
John D Clarke, Petr Novak, April D Lake, Rhiannon N Hardwick, Nathan J Cherrington
BACKGROUND & AIMS: N-linked glycosylation of proteins is critical for proper protein folding and trafficking to the plasma membrane. Drug transporters are one class of proteins that have reduced function when glycosylation is impaired. N-linked glycosylation of plasma proteins has also been investigated as a biomarker for several liver diseases, including non-alcoholic fatty liver disease (NAFLD). The purpose of this study was to assess the transcriptomic expression of genes involved in protein processing and glycosylation, and to determine the glycosylation status of key drug transporters during human NAFLD progression...
January 18, 2017: Liver International: Official Journal of the International Association for the Study of the Liver
https://www.readbyqxmd.com/read/28097771/solution-synthesis-structure-and-co2-reduction-reactivity-of-a-scandium-ii-complex-sc-n-sime3-2-3
#15
David H Woen, Guo P Chen, Joseph W Ziller, Timothy J Boyle, Filipp Furche, William J Evans
The first crystallographically characterizable complex of Sc(2+) , [Sc(NR2 )3 ](-) (R=SiMe3 ), has been obtained by LnA3 /M reactions (Ln=rare earth metal; A=anionic ligand; M=alkali metal) involving reduction of Sc(NR2 )3 with K in the presence of 2.2.2-cryptand (crypt) and 18-crown-6 (18-c-6) and with Cs in the presence of crypt. Dark maroon [K(crypt)](+) , [K(18-c-6)](+) , and [Cs(crypt)](+) salts of the [Sc(NR2 )3 ](-) anion are formed, respectively. The formation of this oxidation state of Sc is also indicated by the eight-line EPR spectra arising from the I=7/2 (45) Sc nucleus...
January 18, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28097770/bond-strength-and-reactivity-scales-for-lewis-superacid-adducts-a-comparative-study-with-in-otf-3-and-al-otf-3
#16
Guillaume Compain Compain, Lauri Sikk, Lionel Massi, Jean-François Gal, Elisabet Duñach
Metal triflates, often called Lewis superacids, are potent catalysts for organic synthesis. However, the reactivity of a given Lewis superacid toward a given base is difficult to anticipate. A systematic screening of catalysts is often necessary when developing synthetic methodologies. Presented herein is the development of quantitative reactivity and bond strength scales by using mass spectrometry (MS). By applying collision induced dissociation (CID) technique to the adducts formed between Lewis superacids Al(OTf)3 or In(OTf)3 with a series of amides bases, including monodentate and bidentate ligands, different dissociation pathways were observed...
January 18, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28097651/the-mysterious-role-of-the-neuronal-anion-exchanger-3
#17
Eric Delpire
No abstract text is available yet for this article.
January 17, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28097273/integration-of-multiple-active-sites-on-large-pore-mesoporous-silica-for-enantioselective-tandem-reactions
#18
Xuelin Xia, Jingjing Meng, Hanxin Wu, Tanyu Cheng, Guohua Liu
Facile construction of a multifunctional heterogeneous catalyst through the assembly of Au/carbene and chiral ruthenium/diamine dual complexes in large-pore mesoporous silica was developed. This enables an efficient one-pot hydration-asymmetric transfer hydrogenation enantioselective tandem reaction of haloalkynes, affording chiral halohydrins with up to 99% enantioselectivity. Combined multifunctionalities, such as substrate-promoted silanol-functionality, BF4(-) anion-bonding gold/carbene and covalent-bonding chiral ruthenium/diamine active centers, contributed cooperatively to the catalytic performance...
January 18, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28096353/high-coulombic-efficiency-aluminum-ion-battery-using-an-alcl3-urea-ionic-liquid-analog-electrolyte
#19
Michael Angell, Chun-Jern Pan, Youmin Rong, Chunze Yuan, Meng-Chang Lin, Bing-Joe Hwang, Hongjie Dai
In recent years, impressive advances in harvesting renewable energy have led to a pressing demand for the complimentary energy storage technology. Here, a high Coulombic efficiency (∼99.7%) Al battery is developed using earth-abundant aluminum as the anode, graphite as the cathode, and a cheap ionic liquid analog electrolyte made from a mixture of AlCl3 and urea in a 1.3:1 molar ratio. The battery displays discharge voltage plateaus around 1.9 and 1.5 V (average discharge = 1.73 V) and yielded a specific cathode capacity of ∼73 mAh g(-1) at a current density of 100 mA g(-1) (∼1...
January 17, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28096342/eight-coordinate-fluoride-in-a-silicate-double-four-ring
#20
Maarten G Goesten, Roald Hoffmann, F Matthias Bickelhaupt, Emiel J M Hensen
Fluoride, nature's smallest anion, is capable of covalently coordinating to eight silicon atoms. The setting is a simple and common motif in zeolite chemistry: the box-shaped silicate double-four-ring (D4R). Fluoride seeks its center. It is the strain of box deformation that keeps fluoride in the middle of the box, and freezes what would be a transition state in its absence. Hypervalent bonding ensues. Fluoride's compactness works to its advantage in stabilizing the cage; chloride, bromide, and iodide do not bring about stabilization due to greater steric repulsion with the box frame...
January 17, 2017: Proceedings of the National Academy of Sciences of the United States of America
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