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Syeda Rabab Naqvi, Gollu Sankar Rao, Wei Luo, Rajeev Ahuja, Tanveer Hussain
First-principles electronic structure calculations were carried out on hexagonal boron nitride (h-BN) sheets functionalized with small molecules, such as OLi, ONa, and Li2 F, to study their hydrogen (H2 ) storage properties. We found that OLi and ONa strongly adsorb on h-BN sheets with reasonably large inter-adsorbent separations, which is desirable for H2 storage. Ab initio molecular dynamics (MD) simulations further confirmed the structural stability of OLi-BN and ONa-BN systems at 400 K. On the other hand, Li2 F molecules form clusters over the surface of h-BN at higher temperatures...
January 18, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Yang Yang, Zhuhua Zhang, Evgeni S Penev, Boris I Yakobson
We report a comprehensive first-principles study of the structural and chemical properties of the recently discovered B40 cage. It is found to be highly reactive and can exothermically dimerize, regardless of the orientation, by overcoming a small energy barrier ≃0.06 eV. The energy gap of the system varies widely with the aggregation of the increasing number of B40 cages, from 3.14 eV in a single B40, to 1.54 eV in the dimer, to 1.25 eV in the trimer. We also explore a recipe for protecting the B40 cage by sheathing it within a carbon shell and identify carbon nanotubes with a radius of ∼6 Å as optimal hosts for an isolated cage...
January 18, 2017: Nanoscale
Resul Ozdemir, Donghee Choi, Mehmet Ozdemir, Hyekyoung Kim, Sinem Tuncel Kostakoğlu, Mustafa Erkartal, Hyungsug Kim, Choongik Kim, Hakan Usta
A new solution-processable and air-stable liquid-crystalline n-channel organic semiconductor (α,ω-2OD-TIFDMT) employing a donor-acceptor-donor (D-A-D) type of π-conjugation has been designed, synthesized, and fully characterized. The new semiconductor exhibits a low LUMO energy (-4.19 eV) and a narrow optical band gap (1.35 eV). Typical pseudo focal-conic fan-shaped texture of a hexagonal columnar liquid crystalline (LC) phase was observed over a wide temperature range. The spin-coated semiconductor thin-films shows the formation of large (~0...
January 17, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Petr Lazar, Michal Otyepka
Molybdenum disulfide, in particular its edges, has attracted considerable attention as possible substitute of platinum catalysts for hydrogen evolution reaction. Complex nature of the reaction complicates its detailed experimental investigations, which are mostly indirect and sample dependent. Therefore, we employed density functional theory calculations to study how the properties of MoS2 Mo-edge influence the thermodynamics of hydrogen adsorption onto the edge. We discuss the effect of the computational model (one-dimensional nanostripe), border symmetry imposed by its length, sulfur saturation of the edge, and dimensionality of the material...
January 18, 2017: Chemistry: a European Journal
Zhen-Long Zhang, Jun-Feng Li, Xiao-Li Wang, Jian-Qiang Qin, Wen-Jia Shi, Yue-Feng Liu, Hui-Ping Gao, Yan-Li Mao
In this paper, N-doped TiO2 (N-TiO2) nanorod arrays were synthesized with hydrothermal method, and perovskite solar cells were fabricated using them as electron transfer layer. The solar cell performance was optimized by changing the N doping contents. The power conversion efficiency of solar cells based on N-TiO2 with the N doping content of 1% (N/Ti, atomic ratio) has been achieved 11.1%, which was 14.7% higher than that of solar cells based on un-doped TiO2. To get an insight into the improvement, some investigations were performed...
December 2017: Nanoscale Research Letters
William Bracamonte-Baran, Jonathan Florentin, Ying Zhou, Ewa Jankowska-Gan, W John Haynes, Weixiong Zhong, Todd V Brennan, Partha Dutta, Frans H J Claas, Jon J van Rood, William J Burlingham
Maternal microchimerism (MMc) has been associated with development of allospecific transplant tolerance, antitumor immunity, and cross-generational reproductive fitness, but its mode of action is unknown. We found in a murine model that MMc caused exposure to the noninherited maternal antigens in all offspring, but in some, MMc magnitude was enough to cause membrane alloantigen acquisition (mAAQ; "cross-dressing") of host dendritic cells (DCs). Extracellular vesicle (EV)-enriched serum fractions from mAAQ(+), but not from non-mAAQ, mice reproduced the DC cross-dressing phenomenon in vitro...
January 17, 2017: Proceedings of the National Academy of Sciences of the United States of America
Marco Degidi, Giuseppe Daprile, Adriano Piattelli
PURPOSE: The aims of this study were to evaluate the ability of a stepped osteotomy to improve dental implant primary stability in low-density bone sites and to investigate possible correlations between primary stability parameters. MATERIALS AND METHODS: The study was performed on fresh humid bovine bone classified as type III. The test group consisted of 30 Astra Tech EV implants inserted following the protocol provided by the manufacturer. The first control group consisted of 30 Astra Tech EV implants inserted in sites without the underpreparation of the apical portion...
January 2017: International Journal of Oral & Maxillofacial Implants
Dilip Kumar Maity, Kenichi Otake, Saheli Ghosh, Hiroshi Kitagawa, Debajyoti Ghoshal
Five sulfonic acid group functionalized mixed ligand coordination polymers (CPs), namely, {[Zn(bpeH)(5-sip)(H2O)]·(H2O)}n (1), {[Cu(pyz)(5-Hsip)(H2O)2]·(H2O)2}n (2), {[Cu(bpee)0.5(5-sip)(H2O)2]·(H2O)4(bpeeH2)0.5}n (3), {[Cu(bpy)(5-Hsip)(H2O)]·(H2O)2}n (4), and {[Cu(bpy)2(5-H2sip)2]·(H2O)6}n (5) [where sip(3-) = 5-sulfoisophthalate; bpe = 4,4'-bispyridylethane; pyz = pyrazine; bpee = 4,4'-bispyridylethylene; bpy = 4,4'-bipyridine], have been synthesized with varying different N,N'-donor linkers using slow diffusion techniques at room temperature...
January 17, 2017: Inorganic Chemistry
Luca Monaco, Mauro Melis, Chiara Biagi, Monia Donati, Ester Sapigni, Alberto Vaccheri, Domenico Motola
BACKGROUND: In July 2012 a new European legislation (Directive 2010/84/EU and Regulation No. 1235/2010) regarding pharmacovigilance has become effective. It has boosted the activity of Signal Detection through a monthly analysis of potential safety signals on EudraVigilance (EV). Our aim is to describe the procedure of signal detection on EV data and to present results obtained by the our pharmacovigilance centre. METHOD: Data are extracted from EV database, which collects suspected Adverse Drug Reactions (ADRs) of medicinal products in Europe...
January 17, 2017: Expert Opinion on Drug Safety
Alex Yong Sheng Eng, Zdeněk Sofer, David Sedmidubský, Martin Pumera
Graphene oxide is an oxidized form of graphene containing a large variety of oxygen groups. Although past models have suggested carboxylic acids to be present in significant amounts, recent evidence has shown otherwise. Toward the production of carboxyl-graphene, a synthetic method is presented herein based on the Kolbe-Schmitt process. A modified procedure of heating graphite oxide in the presence of a KOH/CaO mixture results in up to 11 atom % of carboxylic groups. The graphite oxide starting material and reaction temperature were investigated as two important factors, where a crumpled morphology of graphite oxide flakes and a lower 220 °C temperature preferentially led to greater carboxyl functionalization...
January 17, 2017: ACS Nano
M Kakazey, M Vlasova, V Gómez-Vidales, A Ángeles-Pascual, V A Basiuk
Mixtures of zinc oxide with carbon nanoparticles, ZnO + xC (x = 0.1%, 1% and 3% by weight), were subjected to mechanical processing (MP) in a hermetically sealed grinding chamber. Using electron paramagnetic resonance (EPR) spectroscopy, we monitored the evolution of spin centers in CNPs. While the initial CNPs were EPR silent, their short-duration MP (tMP) gave rise to emergence of low-intensity carbon signal. Increasing the sample temperature at tMP > 9 min induced CNP oxidation, which lead to a dramatic increase in the intensity of C signal...
January 17, 2017: Physical Chemistry Chemical Physics: PCCP
Hui Li, Wei Chen, Xiaopeng Shen, Jingwei Liu, Xuri Huang, Guangtao Yu
On the basis of first-principles computations, we propose a simple and effective strategy through surface-adsorbing 3d-transition metal (TM) atoms, including Ti, Cr, Mn, Fe and Co, to modulate the electronic and magnetic behaviors of zigzag SiC nanoribbons (zSiCNRs), in view of the unique d electronic structures and intrinsic magnetic moments of TM atoms. It is revealed that like applying an electric field, the adsorption of these transition metal atoms can induce an evident change in the electrostatic potential of the substrate zSiCNRs owing to the electron transfer from the TM atom to the substrate...
January 17, 2017: Physical Chemistry Chemical Physics: PCCP
Martin Herder, Fabian Eisenreich, Aurelio Bonasera, Anna Grafl, Lutz Grubert, Michael Pätzel, Jutta Schwarz, Stefan Hecht
Among bistable photochromic molecules diarylethenes (DAEs) possess the distinct feature that upon photoisomerization they undergo a large modulation of their π-electronic system, accompanied by a marked shift of the HOMO/LUMO energies and hence oxidation/reduction potentials. In order to exploit such photoswitchable systems it is important to precisely adjust the absolute position of their HOMO and LUMO levels and to maximize the extent of the photoinduced shifts of these energy levels. Here, we present a comprehensive study detailing how variation of the substitution pattern of DAE compounds, in particular using strongly electron-accepting and chemically stable trifluoromethyl groups either in the periphery or at the reactive carbon atoms, allows for the precise tuning of frontier molecular orbital levels over a broad energy range and the generation of photoinduced shifts of more than 1 eV...
January 17, 2017: Chemistry: a European Journal
Parisa Sadat Pournaderi, Parichehreh Yaghmaei, Hamidreza Khodaei, Zahra Noormohammadi, Seyed Hossein Hejazi
6- gingerol is the major pungent ingredient of ginger with anti-inflammatory and antioxidant properties. In this study, we evaluate the effects of 6- gingerol on the biochemical parameters and ovarian histological improvements in estradiol valerate (EV) induced PCOS rats. Thirty six female Wistar rats were divided into 4 groups: control, received normal diet, PCOS control, received 4 mg/kg EV injection for 28 days and two experimental groups, received an EV injection for 28 days and followed by 6- gingerol (200 μg/kg and 400 μg/kg) for 14 days...
January 13, 2017: Biochemical and Biophysical Research Communications
Bret C Hess, Erik K Swenson
This systematic study of transition metal (TM) substitution for H on graphane TM x H1-x C, (TM  =  Sc, Ti, V, Cr, Mn) combines ab initio calculations and cluster expansion to explore a huge variety of structures in more than 20 supercells over the full concentration range from x  =  0 to 1. We find energetically favorable structures at each concentration in supercells not studied before. At low x the lowest-energy structures contain lines and bands of TM atoms. For the larger atoms (Sc, Ti, V) the ordering becomes complex at higher concentrations, and their increased interaction in graphene causes H atoms to detach from the graphene to positions above the TMs...
January 16, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Feng Li, Junjie Qi, Minxuan Xu, Jiankun Xiao, Yuliang Xu, Xiankun Zhang, Shuo Liu, Yue Zhang
Here surface potential of chemical vapor deposition (CVD) grown 2D MoS2 with various layers is reported, and the effect of adherent substrate and light illumination on surface potential of monolayer MoS2 are investigated. The surface potential of MoS2 on Si/SiO2 substrate decreases from 4.93 to 4.84 eV with the increase in the number of layer from 1 to 4 or more. Especially, the surface potentials of monolayer MoS2 are strongly dependent on its adherent substrate, which are determined to be 4.55, 4.88, 4.93, 5...
January 16, 2017: Small
Michael Kühn, Sergei Lebedkin, Florian Weigend, Andreas Eichhöfer
The optical properties of four isostructural trinuclear chalcogenolato bridged metal complexes [Cu2Sn(SPh)6(PPh3)2], [Cu2Sn(SePh)6(PPh3)2], [Ag2Sn(SPh)6(PPh3)2] and [Cu2Ti(SPh)6(PPh3)2] have been investigated by absorption and photoluminescence spectroscopy and time-dependent density functional theory (TDDFT) calculations. All copper-tin compounds demonstrate near-infrared (NIR) phosphorescence at ∼900-1100 nm in the solid state at low temperature, which is nearly absent at ambient temperature. Stokes shifts of these emissions are found to be unusually large with values of about 1...
January 16, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Kamel A K Gadallah, Demian Marchione, Sven P K Koehler, Martin R S McCoustra
This work investigates the production of molecular hydrogen isotopologues (H2, HD, and D2) during low energy electron irradiation of layered and isotopically labelled thin films of amorphous solid water (ASW) in ultrahigh vacuum. Experimentally, the production of these molecules with both irradiation time and incident electron energy in the range 400 to 500 eV is reported as a function of the depth of a buried D2O layer in an H2O film. H2 is produced consistently in all measurements, reflecting the H2O component of the film, though it does exhibit a modest reduction in intensity at the time corresponding to product escape from the buried D2O layer...
January 16, 2017: Physical Chemistry Chemical Physics: PCCP
Ku-Yen Lin, Yan-Jun Wang, Ko-Lun Chen, Ching-Yuan Ho, Chun-Chuen Yang, Ji-Lin Shen, Kuan-Cheng Chiu
We report on the optical and structural characterization of rubrene polycrystalline films fabricated from vacuum deposition with various substrate temperatures (Tsub). Depending on Tsub, the role of twisted and planar rubrene conformational isomers on the properties of rubrene films is focused. The temperature (T)-dependent inverse optical transmission (IOT) and photoluminescence (PL) spectra were performed on these rubrene films. The origins of these IOT and PL peaks are explained in terms of the features from twisted and planar rubrene molecules and of the band characteristics from rubrene molecular solid films...
January 16, 2017: Scientific Reports
Speranta Avram, Mernea Maria, Eyup Bagci, Lucian Hritcu, Livia-Cristina Borcan, Dan Mihailescu
BACKGROUND: Alzheimer's disease (AD) therapy is based on several natural and synthetic compounds that act as acetylcholinesterase (AChE) and N-methyl-D-aspartate receptor (NMDA) ligands that have limited efficiency in relieving AD symptoms. Recent studies show that inhibitors isolated from Mentha spicata L. subsp. spicata are promising for AD therapy. OBJECTIVE: We aimed to identify novel and more potent phytopharmaceutical compounds for AD treatment by taking into account the compounds from Mentha spicata L...
January 13, 2017: CNS & Neurological Disorders Drug Targets
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