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Daniel Timothy Bowron, Karen J Edler
Wide-angle neutron scattering experiments combined with Empirical Potential Structural Refinement modelling have been used to study the detailed structure of decyltrimethylammonium bromide micelles in the presence of acid solutions of HCl or HBr. These experiments demonstrate considerable variation in micelle structure and water structuring between micelles in the two acid solutions and in comparison with the same micelles in pure water. In the presence of the acids, the micelles are smaller, however in the presence of HCl the micelles are more loosely structured and disordered while in the presence of HBr the micelles are more compact and closer to spherical...
December 9, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Zi-Shuo Yao, Shu-Qi Wu, Yasutaka Kitagawa, Sheng-Qun Su, You-Gui Huang, Guo-Ling Li, Zhong-Hai Ni, Hiroyuki Nojiri, Yoshihito Shiota, Kazunari Yoshizawa, Soonchul Kang, Shinji Kanegawa, Osamu Sato
Atypically anisotropic and large changes in magnetic susceptibility, along with a change in crystalline shape, were observed in a Co(II) complex at near room temperature. This was achieved by combining oxalate molecules, acting as rotor, and a Co(II) ion with unquenched orbital angular momentum. A thermally controlled 90° rotation of the oxalate counter anion triggered a symmetry-breaking ferroelastic phase transition, accompanied by contraction-expansion behavior (ca. 4.5 %) along the long axis of a rod-like single crystal...
December 9, 2016: Angewandte Chemie
Hannah H Lee, Richard H Ho
OATP1B1 (SLCO1B1) is predominantly expressed at the basolateral membrane of hepatocytes and is critically important for the hepatic uptake and clearance of numerous drug substrates and endogenous compounds. In general, the organic anion transporting polypeptides (OATP; SLCO) represent a superfamily of uptake transporters that mediate the sodium-independent transport of a diverse range of amphipathic organic compounds including bile salts, steroid conjugates, thyroid hormones, anionic peptides, numerous drugs and other xenobiotic substances...
December 9, 2016: British Journal of Clinical Pharmacology
Gao-Lei Hou, Cheng-Wen Liu, Ren-Zhong Li, Hong-Guang Xu, Yi Qin Gao, Wei-Jun Zheng
Solvation of salts in water is a fundamental physical chemical process, but the underlying mechanism remains unclear. We investigated the contact ion pair (CIP) to solvent-separated ion pair (SSIP) transition in NaCl(H2O)n clusters with anion photoelectron spectroscopy and ab initio calculations. It is found that the SSIP type of structures show up at n = 2 for NaCl(-)(H2O)n anions. For neutral NaCl(H2O)n, the CIP structures are dominant at n < 9. At n = 9-12, the CIP structures and SSIP structures of NaCl(H2O)n are nearly degenerate in energy, coincident to the H2O:NaCl molar ratio of NaCl saturated solution and implying that the CIP and SSIP structures can coexist in concentrated solutions...
December 9, 2016: Journal of Physical Chemistry Letters
Stefano Artin Serapian, Carles Bo
We here present a series of classical molecular dynamics simulations (MD) on aqueous solutions of the salts Li5AlW12O40 and Li9AlW11O39, providing us with valuable insight on their aggregative behavior. Analysis of relative dipole moment orientation in pairs of aggregated [AlW11O39](9-) excludes that their large dipole moment is behind their greater propensity to aggregate. On the other hand, MD simulations of the aqueous Li(+) salt of the fictitious [AlW12O40](9-)-as high in charge as [AlW11O39](9-), but lacking dipole moment and tetrahedral in shape like [AlW12O40](5-)-reveal that it is in fact the higher negative charge itself that promotes aggregation, by allowing to recruit a higher number of Li(+) countercations, which then act as an electrostatic glue...
December 9, 2016: Journal of Physical Chemistry. B
Arvind Chhabra, Bijay Mukherji, Deepika Batra
OBJECTIVES: Adoptive cancer immunotherapy (ACT) with transgenic T cell receptor (TCR) engineered (TCReng) anti-tumor T cells has produced encouraging results, however, efficacy of these approaches need improvement. Since premature activation induced cell death (AICD) of adoptively administered T cells could be a major impediment, we examined the mechanism(s) underlying AICD in TCReng CD8+ cytolytic T lymphocytes (CTL). METHODS: AICD in human tumor antigen specific MHC class I restricted TCR engineered CD8+ CTL was induced by exposing them to cognate peptide epitope...
December 9, 2016: Expert Opinion on Therapeutic Targets
Zhenxin Zhang, Masahiro Sadakane, Shin-Ichiro Noro, Norihito Hiyoshi, Akihiro Yoshida, Michikazu Hara, Wataru Ueda
An all-inorganic soft framework is rare but interesting for both fundamental research and practical applications. Herein, an all-inorganic soft framework based on a transition metal oxide is reported. The periodic connection of a one-dimensional anionic tungstosellenate molecular wire building block with a CoII ion is used to construct the crystalline material. The crystal structure of the material was determined by high-angle annular dark-field scanning transmission electron microscopy combined with several characterization techniques...
December 9, 2016: Chemistry: a European Journal
Xinlong Ni
A cucurbit[6]uril (Q[6] or CB[6]) outer surface interactions based supramolecular three-dimensional (3D) infinite polycatenated triply-linked cage with 3-torus topology is reported. The arrangement of the poly-interlocked supramolecular framework is evidently stabilized by a favorable combination of weak non-covalent interactions such as hydrophobic effects, hydrogen bonding, ion-dipole interaction, and C-H***Cl interactions in the sold state. Further study suggested that such 3D poly-interlocked species could be rapidly precipitated from the mixture solution in high yield owing to electrostatic interaction of the [CdCl4]2- anion with the electropositive outer surface of Q[6] host...
December 9, 2016: Chemistry: a European Journal
Lin Li, Sheng Shu, Qing Xu, Ya-Hong An, Jin Sun, Shi-Rong Guo
Nitric oxide (NO) and hydrogen peroxide (H2 O2 ), two important signalling molecules, are stimulated in plants by abiotic stresses. In this study, we investigated the role of NO and its interplay with H2 O2 in the response of self-grafted and salt-tolerant pumpkin-grafted (Cucurbita maxima × C. moschata) cucumber seedlings to 80 mM Ca(NO3 )2 stress. Endogenous NO and H2 O2 production in self-grafted seedlings increased in a time-dependent manner, reaching maximum levels after 24 h of Ca(NO3 )2 stress. In contrast, a transient increase in NO production, accompanied by H2 O2 accumulation, was observed at 2 h in rootstock-grafted plants...
December 9, 2016: Physiologia Plantarum
Madhavan Narayanan, Vijay R Singh, Goutham Kodali, Kimberly Jacoby, Katarina Moravcevic, Robert J Stanley
Reduced anionic flavin adenine dinucleotide (FADH-) is the critical cofactor in DNA photolyase (PL) for the repair of cyclobutane pyrimidine dimers (CPD) in UV-damaged DNA. The initial step involves photoinduced electron transfer from *FADH- to the CPD. The adenine (Ade) moiety is nearly stacked with the flavin ring, an unusual conformation compared to other FAD-dependent proteins. The role of this proximity has not been unequivocally elucidated. Some studies suggest that Ade is a radical intermediate, but others conclude that Ade modulates the electron transfer rate constant (kET) through superexchange...
December 9, 2016: Photochemistry and Photobiology
Takahiro Takekiyo, Yoshihiro Koyama, Machiko Shigemi, Kiyoto Matsuishi, Hiroshi Abe, Nozomu Hamaya, Yukihiro Yoshimura
The conformational stability of 1-alkyl-3-methylimidazolium tetrafluoroborate ([Cnmim][BF4], n = 3-8) under high pressure was investigated using Raman spectroscopy to reveal the preferential role of the alkyl-chain length (n) in high-pressure glass transition. To evaluate this, we determined the intensity ratio (r) and differences in the partial molar volume (ΔV(trans→gauche)) between the whole trans and gauche conformers of the [Cnmim] cation using Raman intensities. Interestingly, both values were classified into a two alkyl-chain length region at the border of n = 5...
December 9, 2016: Physical Chemistry Chemical Physics: PCCP
Kei Nishizawa, Takeo Nakanishi, Ikumi Tamai
Pharmacokinetic drug-drug interactions (DDIs) on hepatic organic anion transporting polypeptides (OATPs) are important clinical issues. Previously we reported that plasma dehydroepiandrosterone sulfate (DHEAS) could serve as an endogenous probe to predict OATP-based DDIs in monkeys using rifampicin as an OATP inhibitor. However, since the contribution of hepatic OATPs to the changes of plasma DHEAS by rifampicin remains unclear, here, we evaluated by an in vivo pharmacokinetic study. Since plasma DHEAS concentrations were unexpectedly low in our rat model, disposition of externally administered DHEAS was evaluated...
December 1, 2016: Drug Metabolism and Disposition: the Biological Fate of Chemicals
Gergana S Georgieva, Svetoslav E Anachkov, Ingo Lieberwirth, Kaloian Koynov, Peter A Kralchevsky
The synergistic growth of giant wormlike micelles in ternary mixed solutions composed of an anionic surfactant (sodium laurylethersulfate, SLES), a zwitterionic surfactant (cocamidopropyl betaine, CAPB), and octanoic acid (HC8) is studied. Rheological data and their analysis in terms of Cole-Cole plots and micellar characteristic times are presented, and the micellar structures behind the observed rheological behavior are revealed by cryo-TEM micrographs. The surfactant composition is fixed near the maximal micelle size of the binary SLES + CAPB system, whereas the concentration of HC8 is varied...
December 6, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Liberty Francois-Moutal, Myriam M Ouberai, Ofelia Maniti, Mark E Welland, Agnieszka Strzelecka-Kiliszek, Marcin Wos, Slawomir Pikula, Joanna Bandorowicz-Pikula, Olivier Marcillat, Thierry Granjon
Nucleoside diphosphate kinases (NDPKs) are crucial elements in a wide array of cellular physiological or pathophysiological processes such as apoptosis, proliferation, or metastasis formation. Among the NDPK isoenzymes, NDPK-B, a cytoplasmic protein, was reported to be associated with several biological membranes such as plasma or endoplasmic reticulum membranes. Using several membrane models (liposomes, lipid monolayers, and supported lipid bilayers) associated with biophysical approaches, we show that lipid membrane binding occurs in a two-step process: first, initiation by a strong electrostatic adsorption process and followed by shallow penetration of the protein within the membrane...
December 6, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Chao Wu, Panpan Yang, Zhimin Fu, Yong Peng, Xin Wang, Zuozhi Zhang, Fang Liu, Wenyi Li, Zhizhang Li, Weimin He
We report the atom-economic and environmentally friendly synthesis of Z-β-sulfonyl-a,β-unsaturated carbonyl compounds in water. The mechanism study reveals that the hydrosulfonylation of alkynylcarbonyl compounds with sulfinic acids proceeds via a mechanism that features a sulfinic acid molecule protonating an alkynyl motif to form the ethenium intermediate, which subsequently reacted with a sulfonyl anion to afford the desired products. The ethenium intermediate differentiated electronic and steric demands between the two substituents on the C≡C triple bond of the alkyne substrates to exhibit high regio- and stereoselectivity from a wide range of Z-β-sulfonyl-a,β-unsaturated carbonyl compounds...
November 18, 2016: Journal of Organic Chemistry
Elizabeth H Krenske, Russell C Petter, K N Houk
Additions of cysteine thiols to Michael acceptors underpin the mechanism of action of several covalent drugs (e.g., afatinib, osimertinib, ibrutinib, neratinib, and CC-292). Reversible Michael acceptors have been reported in which an additional electron-withdrawing group was added at the α-carbon of a Michael acceptor. We have performed density functional theory calculations to determine why thiol additions to these Michael acceptors are reversible. The α-EWG group stabilizes the anionic transition state and intermediate of the Michael addition, but less intuitively, it destabilizes the neutral adduct...
December 2, 2016: Journal of Organic Chemistry
Sören Arlt, Jörg Harloff, Axel Schulz, Alrik Stoffers, Alexander Villinger
The reaction of in situ generated E(CN)3 (E = Sb, Bi) with different amounts of [Ph4P]CN and [PPN]CN ([PPN](+) = [Ph3P-N-PPh3](+)) was studied, affording salts bearing the novel ions [E(CN)5](2-), [Bi2(CN)11](5-), and [Bi(CN)6](3-). The valence lone pair of electrons on the central atom of antimony and bismuth(III) compounds can be either sterically active in an unsymmetric fashion (three shorter bonds + x longer bonds) or symmetric (with rather long averaged bonds). In the presence of weakly coordinating cations (e...
December 5, 2016: Inorganic Chemistry
Moritz Malischewski, Dmitry V Peryshkov, Eric V Bukovsky, Konrad Seppelt, Steven H Strauss
The structures of three solvated monovalent cation salts of the superweak anion B12F12(2-) (Y(2-)), K2(SO2)6Y, Ag2(SO2)6Y, and Ag2(H2O)4Y, are reported and discussed with respect to previously reported structures of Ag(+) and K(+) with other weakly coordinating anions. The structures of K2(SO2)6Y and Ag2(SO2)6Y are isomorphous and are based on expanded cubic close-packed arrays of Y(2-) anions with M(OSO)6(+) complexes centered in the trigonal holes of one expanded close-packed layer of B12 centroids (⊙)...
December 5, 2016: Inorganic Chemistry
Cheng-Yang Yue, Xiao-Wu Lei, Yong-Fang Han, Xin-Xiu Lu, Ya-Wei Tian, Jing Xu, Xiao-Fan Liu, Xin Xu
With mixed transition-metal (TM) complex, alkali-metal cations, or halogen anions as structure-directing agents, two types of two-dimensional (2D) layered inorganic-organic hybrid silver bromides were prepared and structurally characterized as K[TM(2,2-bipy)3]2Ag6Br11 (TM = Ni (1), Co (2), Zn (3), Fe (4)) and [TM(2,2-bipy)3]2Ag13Br17 (TM = Ni (5), Co (6), Zn (7), Fe (8)). Compounds 1-4 feature 2D microporous anionic [Ag6Br11](5-) layers composed of [Ag3Br7] secondary building units based on AgBr4 tetrahedral units, and compounds 5-8 contain 2D [Ag13Br16](3-) layers built from the one-dimensional complex [Ag8Br12] and [Ag5Br8] chains...
December 5, 2016: Inorganic Chemistry
Paola Manini, Piero Margari, Christian Pomelli, Paola Franchi, Gennaro Gentile, Alessandra Napolitano, Luca Valgimigli, Cinzia Chiappe, Vincent Ball, Marco d'Ischia
Despite the growing scientific and technological relevance of polydopamine (PDA), a eumelanin-like adhesive material widely used for surface functionalization and coating, knowledge of its structural and physicochemical properties, including in particular the origin of paramagnetic behavior, is still far from being complete. Herein, we disclose the unique ability of ionic liquids (ILs) to disassemble PDA, either as a suspension or as a thin film, up to the nanoscale, and to establish specific interactions with the free radical centers exposed by deaggregation of potential investigative value...
November 23, 2016: Journal of Physical Chemistry. B
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