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Yuan Yin, Deheng Shi, Jinfeng Sun, Zunlue Zhu
This work calculates the potential energy curves of 9 Λ-S and 28Ω states of the NCl+ cation. The technique employed is the complete active space self-consistent field method, which is followed by the internally contracted multireference configuration interaction approach with the Davidson correction. The Λ-S states are X2Π, 12Σ+, 14Π, 14Σ+, 14Σ-, 24Π, 14Δ, 16Σ+, and 16Π, which are yielded from the first two dissociation channels of NCl+ cation. The Ω states are generated from these Λ-S states...
December 9, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Patrick K Wise, Dor Ben-Amotz
Direct (solute-water) and indirect (water-water) contributions to adsorption at an air-water interface are identified using the Widom potential distribution theorem and quantified using molecular dynamics simulations of a liquid water droplet containing either neopentane or iodide-like solutes with charges of 0 or ±1. The results are used to quantitatively compare direct and indirect, energetic and entropic, contributions to adsorption, as well as to critically test surface capillary wave, linear response (LR), and mean field (MF) predictions...
December 15, 2017: Journal of Physical Chemistry. B
Peter B Armentrout, Richard M Cox, Brendan C Sweeny, Shaun G Ard, Nicholas S Shuman, Albert A Viggiano
Reactions of samarium cations with carbonyl sulfide are examined using a guided ion beam tandem mass spectrometer and a variable temperature selected ion flow tube apparatus. Formation of SmS+ + CO is observed in both instruments with a kinetic energy and temperature dependence demonstrating a barrierless reaction occurring with an efficiency of 26 ± 9%. Formation of SmO+ + CS is also observed at high kinetic energies and exhibits a threshold determined as 2.81 ± 0.32 eV, substantially higher than expected from known thermochemistry...
December 15, 2017: Journal of Physical Chemistry. A
Rory Campbell, Sumit Konar, Steven Hunter, Colin Pulham, Peter Portius
The first two examples of the class of tetracoordinate low-valent, mixed-ligand tin azido complexes, Sn(N3)2(L)2, are shown to form upon reaction of SnCl2 with NaN3 and SnF2 with Me3SiN3 in either pyridine or 4-picoline (2, L = py; 3, L = pic). These adducts of Sn(N3)2 are shock- and friction-insensitive and stable at r.t. under an atmosphere of pyridine or picoline, respectively. A new, fast, and efficient method for the preparation of Sn(N3)2 (1) directly from SnF2, and by the stepwise de-coordination of py from 2 at r...
December 15, 2017: Inorganic Chemistry
Teresa Patrícia Magalhães, Sara Cravo, Diana Dias da Silva, Ricardo Jorge Dinis-Oliveira, Carlos Afonso, Maria de Lourdes Bastos, Helena Carmo
The quantification of drugs of abuse in keratinized matrices is becoming of special relevance for monitoring consumption and for post-mortem investigations. We aimed to implement an analytical method for the simultaneous detection of morphine (MORF), 6-monoacetylmorphine (6-MAM), methadone (MET), 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) and 2-ethyl-5-methyl-3,3-diphenylpyrrolidine (EMDP) in nails. After decontamination, the nail samples (30 mg) were submitted to an alkaline digestion followed by a two-step liquid-liquid and SPE extraction using mixed-mode cation exchange cartridges...
December 13, 2017: Journal of Analytical Toxicology
Rafael Ramis, Joaquin Ortega-Castro, Bartolomé Vilanova, Miquel Adrover, Juan Frau
The interactions between the protein α-synuclein and the Zn(II) and Al(III) cations at different sites have been studied at the M06/6-311+G(d,p)/SMD and the wB97X-D/6-311+G(d,p)/SMD levels of theory. For Zn(II), previous experimental studies determined the presence of a high affinity site at Asp121 and a lower affinity one at His50. As for Al(III), an in vitro study showed it to be the most effective cation to induce structural changes in α-synuclein and to accelerate its aggregation. Besides Zn(II) and Al(III), Cu(II) also binds α-synuclein (in fact, its complexes are the most studied and the best characterized ones) forming square planar complexes, and several binding sites are known for it, involving Met1-Asp2 (only in non-acetylated α-synuclein), His50 and Asp121...
December 15, 2017: Journal of Physical Chemistry. A
Ning Zhou, Yiheng Shen, Liang Li, Shunquan Tan, Na Liu, Guanhaojie Zheng, Qi Chen, Huanping Zhou
Halide perovskites with reduced-dimensionality (e.g. quasi-2D, Q-2D) are promising to be stable while remaining the high performance as compared to their three-dimensional counterpart. Generally, they are obtained in (A1)2(A2)n-1PbnI3n+1 thin films by adjusting A site cations, however, the underlying crystallization kinetics mechanism is less explored. In this manuscript, we employed ternary cations halides perovskite (BA)2(MA,FA)3Pb4I13 Q-2D perovskites as an archetypal model, to understand the principles that links the crystal orientation to the carrier behavior in the polycrystalline film...
December 15, 2017: Journal of the American Chemical Society
Lei Zhao, Jing Gao, Qing Liu, Shujun Zhang, Jing-Feng Li
Lead-free dielectric ceramics with high recoverable energy density are highly desired to sustainably meet the future energy demand. AgNbO3-based lead-free antiferroelectric ceramics with double ferroelectric hysteresis loops have been proved to be a potential candidate for energy storage applications. Enhanced energy storage performance with recoverable energy density of 3.3J/cm3, and high thermal stability with minimal energy density variation (<10%) over temperature range of 20-120oC, have been achieved in W-modified AgNbO3 ceramics...
December 15, 2017: ACS Applied Materials & Interfaces
René Uebe, Noa Keren-Khadmy, Natalie Zeytuni, Emanuel Katzmann, Yotam Navon, Geula Davidov, Ronit Bitton, Jürgen M Plitzko, Dirk Schüler, Raz Zarivach
Magnetospirillum gryphiswaldense MSR-1 synthesizes membrane-enclosed magnetite (Fe3 O4 ) nanoparticles, magnetosomes, for magnetotaxis. Formation of these organelles involves a complex process comprising key steps which are governed by specific magnetosome-associated proteins. MamB, a cation diffusion facilitator (CDF) family member has been implicated in magnetosome-directed iron transport. However, deletion mutagenesis studies revealed that MamB is essential for the formation of magnetosome membrane vesicles, but its precise role remains elusive...
December 15, 2017: Molecular Microbiology
Lalita Uribe, Gregor Diezemann, Jürgen Gauss, Jens Preben Morth, Michele Cascella
We performed quantum-chemical calculations, ab initio molecular dynamics, hybrid QM/MM and enhanced sampling metadynamics simulations to investigate the origin of metal specificity in isatin hydrolase from Labrenzia aggregata. The peculiar octahedral binding geometry of the Mn2+ ion in the Michaelis complex includes both the isatin substrate and the catalytic water within the first coordination shell of the cation. Our calculations show that the same arrangement of the ligands cannot be efficiently achieved in the presence of other small divalent cations such as Zn2+ or Cu2+...
December 15, 2017: Chemistry: a European Journal
Animesh Mondal, Barnali Naskar, Sanchita Goswami, Chandraday Prodhan, Keya Chaudhuri, Chhanda Mukhopadhyay
An easy access to an amine-appended spiro[indoline-3,4'-pyridine] ON-OFF chemosensor by a one-pot four-component reaction using commercially available and an environmentally benign catalytic amount of molecular I2 (10 mol%) in aqueous ethanol at ambient temperature is described. The generated system could be utilized for the selective detection of Cu2+ as it demonstrated a colorimetric naked eye change along with an ON-OFF fluorescence response towards Cu2+ at physiological pH. The sensors exhibited high selectivity for Cu2+ over other common cations with detection limit in the range of 10-7 (M)...
December 15, 2017: Organic & Biomolecular Chemistry
William J M Blackaby, Sara Sabater, Rebecca C Poulten, Michael J Page, Andrea Folli, Vera Krewald, Mary F Mahon, Damien M Murphy, Emma Richards, Michael K Whittlesey
Bromide abstraction from the three-coordinate Ni(i) ring-expanded N-heterocyclic carbene complex [Ni(6-Mes)(PPh3)Br] (1; 6-Mes = 1,3-bis(2,4,6-trimethylphenyl)-3,4,5,6-tetrahydropyrimidin-2-ylidene) with TlPF6 in THF yields the T-shaped cationic solvent complex, [Ni(6-Mes)(PPh3)(THF)][PF6] (2), whereas treatment with NaBArF4 in Et2O affords the dimeric Ni(i) product, [{Ni(6-Mes)(PPh3)}2(μ-Br)][BArF4] (3). Both 2 and 3 act as latent sources of the cation [Ni(6-Mes)(PPh3)]+, which can be trapped by CO to give [Ni(6-Mes)(PPh3)(CO)]+ (5)...
December 15, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Emanuelle Jesus Silva, Leonardo Gomes Souza, Luis Antonio Dantas Silva, Stephania Fleury Taveira, Raquel Ciffarello Guilger, Luciano Morais Liao, Luiz Henrique Keng Queiroz Junior, Mabio Joao Santana, Ricardo Neves Marreto
BACKGROUND: Topotecan (TPT) is a water-soluble derivate of camptothecin, which undergoes ring-opening hydrolysis in neutral solutions, leading to stability loss and poor cellular uptake. Lipid nanoencapsulation can improve TPT stability, and polymer-lipid hybrid nanoparticles (PLN) are interesting alternatives to improve TPT nanoencapsulation. OBJECTIVE: This study seeks to prepare complexes between the cationic TPT and the negatively charged dextran sulfate (DS) with a view of improving drug loading, chemical stability and release control...
December 14, 2017: Current Drug Delivery
Yihui Wu, Peng Wang, Shubo Wang, Zenghua Wang, Bing Cai, Xiaojia Zheng, Yu Chen, Ningyi Yuan, Jianning Ding, Wen-Hua Zhang
It is essential to minimize the interfacial trap states and improve the carrier collection for high efficiency perovskite solar cells (PSCs). Herein, we present a facile method to construct a p-type graded heterojunction (GHJ) in the normal PSCs by deploying a gradient distribution of hole-transporting materials (PTAA in this case) in the shallow perovskite layer. The formation of the GHJ structure facilitates charge transfer and collection, passivates interfacial trap states, thus delivering a power conversion efficiency (PCE) of 20...
December 15, 2017: ChemSusChem
Roland Tolulope Loto
The synergistic properties of the combined admixture of benzenecarbonitrile and 5-bromovanillin (BNV) on the corrosion resistance of 1018 carbon steel in 1 M HCl was analysed with potentiodynamic polarization technique, weight loss method, micro-analytical studies and ATF-FTIR spectroscopy. Results obtained show the admixed organic compound was effective with optimal corrosion inhibition values of 99.33% and 90.34% at 1.25% BNV concentration from both electrochemical methods due to the effective inhibition action and passivation characteristics of the protonated inhibitor molecules in the acid solution...
December 14, 2017: Scientific Reports
Thomas Maxwell Kaiser, Steven A Kell, Hirofumi Kusumoto, Gil Shaulsky, Subhrajit Bhattacharya, Matthew P Epplin, Katie L Strong, Eric J Miller, Bryan D Cox, David S Menaldino, Dennis C Liotta, Stephen F Traynelis, Pieter Buys Burger
NMDA receptors are ligand-gated, cation-selective channels that mediate a slow component of excitatory synaptic transmission. Subunit-selective positive allosteric modulators of NMDA receptor function have therapeutically-relevant effects on multiple processes in the brain. A series of pyrrolidinones, such as PYD-106, that selectively potentiate NMDA receptors that contain the GluN2C subunit have structural determinants of activity that reside between the GluN2C amino terminal domain and the GluN2C agonist binding domain, suggesting a unique site of action...
December 14, 2017: Molecular Pharmacology
Zhongxin Ma, Kyle T Strickland, Michelle D Cherne, Esha Sehanobish, Kyle H Rohde, William T Self, Victor L Davidson
The Rv2633c gene in Mycobacterium tuberculosis is rapidly upregulated after macrophage infection, suggesting that Rv2633c is involved in M. tuberculosis pathogenesis. However, the activity and role of the Rv2633c protein in host colonization is unknown. Here, we analyzed the Rv2633c protein sequence, which revealed the presence of an HHE cation-binding domain common in hemerythrin-like proteins. Phylogenetic analysis indicated that Rv2633c is a member of a distinct subset of hemerythrin-like proteins exclusive to mycobacteria...
December 14, 2017: Journal of Biological Chemistry
Dariia O Dryn, Mariia I Melnyk, Lina T Al Kury, Yuriy I Prylutskyy, Uwe Ritter, Alexander V Zholos
The effect of water-soluble pristine C60 fullerene nanoparticles (C60NPs) on receptor-operated cation channels formed by TRPC4/C6 proteins in ileal smooth muscle cells was investigated for the first time. Activation of these channels subsequent to acetylcholine binding to the expressed in these cells M2 and M3 muscarinic receptors represents the key event in the parasympathetic control of gastrointestinal smooth muscle motility and cholinergic excitation-contraction coupling. Experiments were performed on single collagenase-dispersed mouse ileal myocytes using patch-clamp techniques with symmetrical 125mM Cs+ solutions and [Ca2+]i 'clamped' at 100nM in order to isolate the muscarinic cation current (mICAT)...
December 11, 2017: Cellular Signalling
Zhong-Yu Wang, Ying-Yi Liu, Guo-Hui Liu, Hai-Bin Lu, Cui-Ying Mao
Cardiovascular disease (CVD) is a key cause of deaths worldwide, comprising 15-17% of healthcare expenditure in developed countries. Current records estimate an annual global average of 30 million cardiac dysfunction cases, with a predicted escalation by two-three folds for the next 20-30years. Although β-blockers and angiotensin-converting-enzymes are commonly prescribed to control CVD risk, hepatotoxicity and hematological changes are frequent adverse events associated with these drugs. Search for alternatives identified endogenous cofactor l-carnitine, which is capable of promoting mitochondrial β-oxidation towards a balanced cardiac energy metabolism...
December 11, 2017: Life Sciences
Shasha Liu, Yuanrong Zhu, Leizhen Liu, Zhongqi He, John P Giesy, Yingchen Bai, Fuhong Sun, Fengchang Wu
Complexation and coagulation of plant-derived dissolved organic matter (DOM) by metal cations are important biogeochemical processes of organic matter in aquatic systems. Thus, coagulation and fractionation of DOM derived from aquatic plants by Ca(II), Al(III), and Fe(III) ions were investigated. Metal ion-induced removal of DOM was determined by analyzing dissolved organic carbon in supernatants after addition of these metal cations individually. After additions of metal ions, both dissolved and coagulated organic fractions were characterized by use of fluorescence excitation emission matrix-parallel factor (EEM-PARAFAC) analysis and Fourier transform infrared (FT-IR) spectroscopy...
December 11, 2017: Environmental Pollution
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