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Aurideia P de Sousa, Edinilton M Carvalho, Javier Ellena, Eduardo H S Sousa, Jackson R de Sousa, Luiz G F Lopes, Peter C Ford, Alda K M Holanda
The ruthenium(II) compounds cis-[Ru(bpy)2(4-bzpy)(CO)](PF6)2 (I) and cis-[Ru(bpy)2(4-bzpy)(Cl)](PF6) (II) (4-bzpy=4-benzoylpyridine, bpy=2,2'-bipyridine) were synthesized and characterized by spectroscopic and electrochemical techniques. The crystal structure of II was determined by X-ray diffraction. The photochemical behavior of I in aqueous solution shows that irradiation with ultraviolet light (365nm) releases both CO and 4-bzpy leading to the formation of the cis-[Ru(bpy)2(H2O)2](2+) ion as identified by NMR and electronic spectroscopy...
May 15, 2017: Journal of Inorganic Biochemistry
Tingting You, Yuhui Wang, Kefa Li, Danting Zhang, Huan Wei, Yanhong Luo, Hua Li, Yongzhi Lu, Xunchen Su, Zhihe Kuang
SPRY domain-containing SOCS box protein 2 (SPSB2) is a negative regulator of inducible nitric oxide synthase (iNOS) that modulates the lifetime of iNOS and thus the levels of nitric oxide (NO) production. Inhibitors that can disrupt the endogenous SPSB2-iNOS interaction and augment NO production have potential as novel antimicrobial and anticancer drugs. In this study, we have designed a cyclic peptide (cR8), containing an RGD motif and the SPSB2 binding motif (DINNNV). ITC and chemical shift perturbation showed that cR8 binds to the iNOS binding site on SPSB2 with a Kd of 671 nM, and saturation transfer difference NMR showed that cR8 binds to αvβ3 integrin-expressing cells...
May 23, 2017: Biochemical and Biophysical Research Communications
Sang-Hyeok Cho, Kwanghee Cho, No-Won Park, Soonyong Park, Jung-Hyuk Koh, Sang-Kwon Lee
We report p-type tin monoselenide (SnSe) single crystals, grown in double-sealed quartz ampoules using a modified Bridgman technique at 920 °C. X-ray powder diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX) measurements clearly confirm that the grown SnSe consists of single-crystal SnSe. Electrical transport of multi-layer SnSe nanoflakes, which were prepared by exfoliation from bulk single crystals, was conducted using back-gated field-effect transistor (FET) structures with Au and Ti contacts on SiO2/Si substrates, revealing that multi-layer SnSe nanoflakes exhibit p-type semiconductor characteristics owing to the Sn vacancies on the surfaces of SnSe nanoflakes...
December 2017: Nanoscale Research Letters
Kushol Gupta, Robert Sharp, Jimmy B Yuan, Huiguang Li, Gregory D Van Duyne
Serine integrases are bacteriophage enzymes that carry out site-specific integration and excision of their viral genomes. The integration reaction is highly directional; recombination between the phage attachment site attP and the host attachment site attB to form the hybrid sites attL and attR is essentially irreversible. In a recent model, extended coiled-coil (CC) domains in the integrase subunits are proposed to interact in a way that favors the attPxattB reaction but inhibits the attLxattR reaction. Here, we show for the Listeria innocua integrase (LI Int) system that the CC domain promotes self-interaction in isolated Int and when Int is bound to attachment sites...
May 26, 2017: Nucleic Acids Research
Lori S Sullivan, Sara J Bowne, Daniel C Koboldt, Elizabeth L Cadena, John R Heckenlively, Kari E Branham, Dianna H Wheaton, Kaylie D Jones, Richard S Ruiz, Mark E Pennesi, Paul Yang, David Davis-Boozer, Hope Northrup, Vsevold V Gurevich, Rui Chen, Mingchu Xu, Yumei Li, David G Birch, Stephen P Daiger
Purpose: To identify the causes of autosomal dominant retinitis pigmentosa (adRP) in a cohort of families without mutations in known adRP genes and consequently to characterize a novel dominant-acting missense mutation in SAG. Methods: Patients underwent ophthalmologic testing and were screened for mutations using targeted-capture and whole-exome next-generation sequencing. Confirmation and additional screening were done by Sanger sequencing. Haplotypes segregating with the mutation were determined using short tandem repeat and single nucleotide variant polymorphisms...
May 1, 2017: Investigative Ophthalmology & Visual Science
Dima Bolmatov, Mikhail Zhernenkov, Lewis Sharpnack, Dena M Agra-Kooijman, Satyendra Kumar, Alexey Suvorov, Ronald Pindak, Yong Q Cai, Alessandro Cunsolo
The investigation of phononic collective excitations in soft matter systems at the molecular scale has always been challenging due to limitations of experimental techniques in resolving low-energy modes. Recent advances in Inelastic X-ray Scattering (IXS) enabled the study of such systems with unprecedented spectral contrast at meV excitation energies. In particular, it has become possible to shed light on the low-energy collective motions in materials whose morphology and phase behavior can easily be manipulated, such as mesogenic systems...
May 26, 2017: Nano Letters
Mario Wibowo, Qian Wang, Jeff Holst, Jonathan M White, Andreas Hofmann, Rohan A Davis
Seven new dihydro-β-agarofurans, celastrofurans A-G (1-7), along with two known secondary metabolites, 9β-benzoyloxy-1α-furoyloxydihydro-β-agarofuran (8) and (1R,2R,4R,5S,7R,9S,10R)-2-acetoxy-9-benzoyloxy-1-furoyloxydihydro-β-agarofuran (9), were obtained from the leaves of the Australian rainforest vine, Celastrus subspicata. The structures of the new compounds were determined by detailed spectroscopic (1D/2D NMR) and MS data analysis. The absolute configurations of compounds 1-4 were defined by ECD and single-crystal X-ray diffraction studies...
May 26, 2017: Journal of Natural Products
Xuelong Wang, Ruijuan Xiao, Hong Li, Liquan Chen
Through first-principles calculations and crystal structure prediction techniques, we identify a new layered oxysulfide LiAlSO in orthorhombic structure as a novel lithium superionic conductor. Two kinds of stacking sequences of layers of AlS_{2}O_{2} are found in different temperature ranges. Phonon and molecular dynamics simulations verify their dynamic stabilities, and wide band gaps up to 5.6 eV are found by electronic structure calculations. The lithium migration energy barrier simulations reveal the collective interstitial-host ion "kick-off" hopping mode with barriers lower than 50 meV as the dominating conduction mechanism for LiAlSO, indicating it to be a promising solid-state electrolyte in lithium secondary batteries with fast ionic conductivity and a wide electrochemical window...
May 12, 2017: Physical Review Letters
Doinita Neiner, Yulia V Sevryugina, Larry S Harrower, David M Schubert
Millions of tons of sodium borates are used annually by global industries in diverse applications important to modern society. The Na2O-B2O3-H2O phase diagram in the 0-100 °C temperature range contains 13 unique hydrated crystalline sodium borates, including five important industrial products. Structures were previously reported for each of these except for that having the highest boron content, known as sodium enneaborate, Na4B18O29·11H2O or 2Na2O·9B2O3·11H2O (1). Here we report the single-crystal structure of 1, revealing the structural formula Na2[B8O11(OH)4]·B(OH)3·2H2O, and describe some of its properties and relationships to other sodium borates...
May 26, 2017: Inorganic Chemistry
Dong-Qing Wu, David Kempe, Yan Zhou, Lin-Dan Deng, Dong Shao, Xiao-Qin Wei, Le Shi, Kim R Dunbar, Xin-Yi Wang
Two cyanide-bridged compounds based on the Fe(II) cation and the anisotropic [Mo(III)(CN)7](4-) anion, namely, {Fe2(H2O)5[Mo(CN)7]·5H2O}n (1) and {[NH2(CH3)2]2Fe5(H2O)10[Mo(CN)7]3·8H2O}n (2), have been prepared. Single crystal X-ray analyses revealed that their structures exhibit different three-dimensional topologies as a result of the addition of [NH2(CH3)2](+) during the synthesis of 2. For both 1 and 2, the geometry of the [Mo(CN)7](4-) unit is a slightly distorted capped trigonal prism; all Fe(II) centers are hexacoordinate and adopt a distorted octahedral configuration...
May 26, 2017: Inorganic Chemistry
Lanhua Chen, Juan Diwu, Daxiang Gui, Yaxing Wang, Zhehui Weng, Zhifang Chai, Thomas E Albrecht-Schmitt, Shuao Wang
The oxidation state greatly affects the chemical behavior of uranium in the nuclear fuel cycle and in the environment. Phosphonate ligands, on the other hand, show strong complexation toward uranium at different oxidation states and are widely used in nuclear fuel reprocessing. Therefore, in this work, the reduction behavior of U(VI) with the presence of a phosphonate ligand is investigated under mild solvothermal conditions. By adjusting the reaction time, temperature, and counterion species, a series of uranium diphosphonates including two U(VI), seven U(IV), two mixed-valent U(IV/VI), and one distinct U(IV/V/VI) compounds were obtained...
May 26, 2017: Inorganic Chemistry
Peyman Taheri, Hossain M Fahad, Mahmut Tosun, Mark Hettick, Daisuke Kiriya, Kevin Chen, Ali Javey
A major challenge in transistor technology scaling is the formation of controlled ultra-shallow junctions with nanometer-scale thickness and high spatial uniformity. Monolayer doping (MLD) is an efficient method to form such nanoscale junctions, where the self-limiting nature of semiconductor surfaces is utilized to form adsorbed monolayers of dopant-containing molecules followed by rapid thermal annealing (RTA) to diffuse the dopants to a desired depth. Unlike ion implantation, the process does not induce crystal damage, thus making it highly attractive for nanoscale transistor processing...
May 26, 2017: ACS Applied Materials & Interfaces
Mandira Nandi, Saikat Santra, Bidyut Akhuli, Pradyut Ghosh
The threading of 'U' shaped bent axles having diverse functionalities (Axle1-Axle10) is investigated by using a heteroditopic amido-amine macrocyclic (MC) wheel via Ni(II) or Cu(II) metal ion templation. These bent shaped axles are the derivatives of 4,4'-substituted 2,2'-bipyridine, which are composed of various terminal groups like alkene, alkyne, bromide, hydroxyl and azide. Such metallo [2]pseudorotaxanes are well characterised by ESI-MS, EPR and FT-IR spectroscopic studies, UV-Vis absorption studies, elemental analysis and single-crystal X-ray diffraction studies wherever possible...
May 26, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
María Carmona, Ricardo Rodríguez, Isabel Méndez, Vincenzo Passarelli, Fernando J Lahoz, Pilar García-Orduña, Daniel Carmona
Ligands LH1-LH3 have been prepared by two successive condensation/reduction steps. These ligands react with MCl3 (M = Rh, Ir) rendering the trichlorido complexes [MCl3(κ(3)N,N',P-LH)] (M = Rh, LH = LH1 (1), LH2 (2), LH3 (3); M = Ir, LH = LH1, (4)) as racemic mixtures of fac and mer isomers. Only one of the two possible fac isomers was detected. The mer isomer of the rhodium compounds 1-3 quantitatively isomerizes to the more stable fac isomer, whereas the mer isomer of the iridium complex 4 does not. DFT calculations indicate a dissociative pathway for this isomerization...
May 26, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Xiaoqiang Du, Jingwei Huang, Yong Ding
Developing noble metal-free water oxidation catalysts is essential for many energy conversion/storage processes (e.g., water splitting). Herein, we report a facile synthesis of CuO microspheres composed of ultrathin, single-crystal-like nanosheets via a simple solution method. The as-obtained CuO microspheres can serve as an active and stable water oxidation catalyst under electrochemical reaction conditions, owing to their unique structural features. In electrochemical water oxidation, this catalyst affords a current density of 10 mA cm(-2) (a value related to practical relevance) at an overpotential of ∼0...
May 26, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Upasana Sridharan, Seiki Kuramitsu, Shigeyuki Yokoyama, Thirumananseri Kumarevel, Karthe Ponnuraj
The Aq1627 gene from Aquifex aeolicus, a hyperthermophilic bacterium has been cloned and overexpressed in Escherichia coli. The protein was purified to homogeneity and its X-ray crystal structure was determined to 1.3 Å resolution using multiple wavelength anomalous dispersion phasing. The structural and sequence analysis of Aq1627 is suggestive of a putative phosphoglucosamine mutase. The structural features of Aq1627 further indicate that it could belong to a new subclass of the phosphoglucosamine mutase family...
May 26, 2017: Molecular BioSystems
Rui-Bin Zhang, Goran Ungar, Xiangbing Zeng, Zhihao Shen
Using 2D X-ray diffraction and AFM we studied the configuration, in cylindrical confinement, of hexagonal columnar phases that anchor homeotropically, i.e. with the columns normal to the pore wall. A wide range of pore diameters, from 20 nm to 100 μm, were explored by employing anodic alumina membranes and glass capillaries. The compounds used were a small discotic, hexakis(hexyloxy)triphenylene (HAT6), a large discotic hexa-peri-hexabenzocoronene (HBC), and a T-shaped bolaamphiphile, forming a honeycomb-type columnar phase...
May 26, 2017: Soft Matter
Mateusz Odziomek, Frédéric Chaput, Anna Rutkowska, Konrad Świerczek, Danuta Olszewska, Maciej Sitarz, Frédéric Lerouge, Stephane Parola
High-performance Li-ion batteries require materials with well-designed and controlled structures on nanometre and micrometre scales. Electrochemical properties can be enhanced by reducing crystallite size and by manipulating structure and morphology. Here we show a method for preparing hierarchically structured Li4Ti5O12 yielding nano- and microstructure well-suited for use in lithium-ion batteries. Scalable glycothermal synthesis yields well-crystallized primary 4-8 nm nanoparticles, assembled into porous secondary particles...
May 26, 2017: Nature Communications
L F White, J R Darling, D E Moser, D A Reinhard, T J Prosa, D Bullen, D Olson, D J Larson, D Lawrence, I Martin
Resolving the timing of crustal processes and meteorite impact events is central to understanding the formation, evolution and habitability of planetary bodies. However, identifying multi-stage events from complex planetary materials is highly challenging at the length scales of current isotopic techniques. Here we show that accurate U-Pb isotopic analysis of nanoscale domains of baddeleyite can be achieved by atom probe tomography. Within individual crystals of highly shocked baddeleyite from the Sudbury impact structure, three discrete nanostructural domains have been isolated yielding average (206)Pb/(238)U ages of 2,436±94 Ma (protolith crystallization) from homogenous-Fe domains, 1,852±45 Ma (impact) from clustered-Fe domains and 1,412±56 Ma (tectonic metamorphism) from planar and subgrain boundary structures...
May 26, 2017: Nature Communications
Da-Hye Lim, Parthiban Ramasamy, Do-Hyun Kwak, Jong-Soo Lee
Recently, metal halide perovskite nanocrystals have demonstrated outstanding properties in various optoelectronic applications. Cesium lead halides (CsPbX3) are the most studied perovskites in nanoscale dimensions. However, halide perovskite nanocrystals with other cations have rarely been reported. It is important to develop new perovskite compositions to further expand their application in various fields. In this paper, we first report the synthesis of colloidal rubidium lead iodide (RbPbI3) nanowires (NWs)...
May 26, 2017: Nanotechnology
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