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Julian Bejarano, Rainer Detsch, Aldo R Boccaccini, Humberto Palza
Novel multifunctional scaffolds for bone regeneration can be developed by incorporation of bioactive glasses doped with therapeutic and antibacterial metal ions, such as copper (Cu) and zinc (Zn), into a biodegradable polymer. In this context, porous composite materials of biodegradable poly(D, L-lactide) (PDLLA) mixed with sol-gel bioactive glasses (BG) of chemical composition 60SiO2 ; 25CaO; 11Na2 O; and 4P2 O5 (mol.%) doped with either 1 mol% of CuO or ZnO, and with both metals, were prepared. The cytocompatibility of the scaffolds on bone marrow stromal cells (ST-2) depended on both, the amount of glass filler and the concentration of metal ion, as evaluated by lactate dehydrogenase (LDH) activity, cell viability (water-soluble tetrazolium salt (WST-8)), and by cell morphology (scanning electron microscopy (SEM)) tests...
October 26, 2016: Journal of Biomedical Materials Research. Part A
Binbin Fang, Jing Guo, Fuxing Li, John P Giesy, Lianjun Wang, Wei Shi
Industrialized development of the Yangtze River Delta, China, has resulted in larger amounts of wastes, including sludges from treatment of these wastes. Methods to manage and dispose, including reuse were urgently needed. Sludge and reused products were collected from two largest factories, KEYUAN and HENGJIA where treated sludges were turned into bricks or sludge cake to be placed in landfills, respectively. Metals and organic compounds were quantified in sludges and leachates assessed by use of toxicity characterized leaching procedure (TCLP) while acute toxicity was determined by Daphnia magna...
October 23, 2016: Chemosphere
F Pelin Kinik, Cigdem Altintas, Volkan Balci, Burak Koyuturk, Alper Uzun, Seda Keskin
Experiments were combined with atomically-detailed simulations and density functional theory (DFT) calculations to understand the effect of incorporation of an ionic liquid (IL), 1-n-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]), into a metal organic framework (MOF with a zeolitic imidazolate framework), ZIF-8, on the CO2 separation performance. The interactions between [BMIM][PF6] and ZIF-8 were examined in deep detail and their consequences on CO2/CH4, CO2/N2, and CH4/N2 separation have been elucidated by using experimental measurements complemented by DFT calculations and atomically-detailed simulations...
October 26, 2016: ACS Applied Materials & Interfaces
Luning Chen, Huiqi Li, Wen-Wen Zhan, Zhenming Cao, Jiayu Chen, Qiaorong Jiang, Ya-Qi Jiang, Zhaoxiong Xie, Qin Kuang, Lan-Sun Zheng
For new composite materials with functional nanoparticles (NPs) embedded in metal organic frameworks (MOFs), rational design as well as precise control over their architectures are imperative for achieving enhanced performance and novel functions. Especially in catalysis, the activity and selectivity of such composite materials are strongly determined by the encapsulation state and thickness of the MOF shell, which greatly influences the diffusion and adsorption of substance molecules onto the NP surface. In this study, MOF-74(Ni)-encapsulated Rh-Ni hierarchical heterostructures (Rh-Ni@MOF-74(Ni)) were successfully constructed using magnetic Rh-Ni-alloyed nanoflowers (NFs) as a self-sacrificial template...
October 26, 2016: ACS Applied Materials & Interfaces
Shoji Nishio, Shigeo Fukunishi, Shinichi Yoshiya, David C Sing, Erik N Hansen, Thomas P Vail
The aim of this study was to examine the clinical characteristics of patients who required revision and the rate of early complications after revision for metal-on-metal total hip arthroplasty (MOM THA) and metal-on-polyethylene total hip arthroplasty (MOP THA). Matched cohorts were selected by retrospective review from a single-center database of revision THAs for failed MOM and MOP THAs from 2010 to 2014. A total of 140 hips in 140 patients comprised the study population; 39 revisions were performed for failed MOM THAs (MOM group), and 101 revisions were performed for failed MOP THAs (MOP group)...
October 25, 2016: Orthopedics
David E Friesem, Noa Lavi, Marco Madella, P Ajithprasad, Charles French
Hunter-gatherer societies have distinct social perceptions and practices which are expressed in unique use of space and material deposition patterns. However, the identification of archaeological evidence associated with hunter-gatherer activity is often challenging, especially in tropical environments such as rainforests. We present an integrated study combining ethnoarchaeology and geoarchaeology in order to study archaeological site formation processes related to hunter-gatherers' ways of living in tropical forests...
2016: PloS One
Zhida Zheng, Xiaocha Wang, Wenbo Mi
The strain and electric-field effects on the electronic structure of MoTe2/WTe2 van der Waals heterostructures are investigated by first-principles calculations. The MoTe2/WTe2 heterostructures are indirect band gap semiconductors under different strains except for 2%. At a strain from  -6% to 6% under a zero electric field, the band gap is 0.56, 0.62, 0.69, 0.62, 0.46, 0.37 and 0.29 eV, respectively. Meanwhile, spin splitting at the conduction band minimum (CBM) decreases monotonically from 76-1 meV, and that at the valance band maximum (VBM) is 232, 266, 292, 307, 319, 302 and 283 meV...
October 26, 2016: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Habib Rostami, Ali G Moghaddam, Reza Asgari
We investigate the spin relaxation and Kondo resistivity caused by magnetic impurities in doped transition metal dichalcogenide monolayers. We show that momentum and spin relaxation times, due to the exchange interaction by magnetic impurities, are much longer when the Fermi level is inside the spin-split region of the valence band. In contrast to the spin relaxation, we find that the dependence of Kondo temperature T K on the doping is not strongly affected by the spin-orbit induced splitting, although only one of the spin species are present at each valley...
October 26, 2016: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Michael Martins, Wilfried Wurth
Clusters are small systems ranging from a few atoms up to several thousand atoms. They are of high interest in basic research, but also for applications due to their specific electronic, magnetic or chemical properties depending on size and composition. For small clusters, quantum size effects play an important role and specific material properties might be tailored by choosing a special size or composition of the cluster. Here, we review the magnetic properties of adatoms and supported small mass-selected transition-metal clusters in the few-atom limit investigated by x-ray magnetic circular dichroism spectroscopy in the soft x-ray regime...
October 26, 2016: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Ming Wang, Qiaoling Fan, Xuefeng Jiang
A facile, straightforward protocol was established for diarylannulated sulfide and selenide construction through S-I and Se-I exchange without transition metal assistance. Elemental sulfur and selenium served as the chalcogen source. Diarylannulated sulfides were systematically achieved from a five- to eight-membered ring. A trisulfur radical anion was demonstrated as the initiator for this radical process via electron paramagnetic resonance (EPR) study. OFET molecules [1]benzothieno[3,2-b][1]benzothiophene (BTBT) and [1]benzothieno[3,2-b][1]benzoselenophene (BTBS) were efficiently established...
October 26, 2016: Organic Letters
A Leela Siva Kumari, Alla Siva Reddy, K C Kumara Swamy
An approach to both 1,3- and 1,4-oxazines is developed by the cascade cyclization of epoxy ynamides under transition metal-free conditions. Thus, while 1,3-oxazines are obtained in a regio- and stereoselective manner by using base, cyclization of epoxy ynamides with sodium azide as a nucleophile results in 1,4-oxazines. Deuterium-labeling experiment demonstrates the role of water as a proton source in the formation of 1,4-oxazines. Epoxy tethered alkyne precursors provide 1,4-oxazines that undergo click reaction...
October 26, 2016: Organic Letters
Debodyuti Dutta, Sabyashachi Mishra
In the fight against bacterial infections and antibiotic resistance, the dapE-encoded N-succinyl-L,L-diaminopimelic acid desuccinylase (DapE) is a potentially safe target enzyme. The role of Glu134, His67, and His349 residues in the binding and hydrolysis of N-succinyl-L,L-diaminopimelic acid (SDAP) are investigated by employing MD simulation and hybrid QM/MM calculations of E134D, H67A, and H349A mutants of DapE. The free energy of substrate binding obtained from MM-PBSA approach correctly reproduced the experimentally observed ordering of substrate affinity, i...
October 26, 2016: Journal of Physical Chemistry. B
Tejas A Shastry, Itamar Balla, Hadallia Bergeron, Samuel H Amsterdam, Tobin J Marks, Mark C Hersam
Two-dimensional transition metal dichalcogenides (TMDCs) have recently attracted attention due to their superlative optical and electronic properties. In particular, their extraordinary optical absorption and semiconducting bandgap have enabled demonstrations of photovoltaic response from heterostructures comprised of TMDCs and other organic or inorganic materials. However, these early studies were limited to devices at the micron-scale and/or failed to exploit the unique optical absorption properties of single-layer TMDCs...
October 26, 2016: ACS Nano
Eileen K Jaffe
Porphobilinogen synthase (PBGS), also known as 5-aminolevulinate dehydratase, is an essential enzyme in the biosynthesis of all tetrapyrroles, which function in respiration, photosynthesis, and methanogenesis. Throughout evolution, PBGS adapted to a diversity of cellular niches and evolved to use an unusual variety of metal ions both for catalytic function and to control protein multimerization. With regard to the active site, some PBGSs require Zn(2+); a subset of those, including human PBGS, contain a constellation of cysteine residues that acts as a sink for the environmental toxin Pb(2+)...
October 26, 2016: Accounts of Chemical Research
Yao Liu, Volodimyr V Duzhko, Zachariah A Page, Todd Emrick, Thomas P Russell
Conjugated polymer zwitterions (CPZs) are neutral, hydrophilic, polymer semiconductors. The pendent zwitterions, viewed as side chain dipoles, impart solubility in polar solvents for solution processing, and open opportunities as interfacial components of optoelectronic devices, for example, between metal electrodes and organic semiconductor active layers. Such interlayers are crucial for defining the performance of organic electronic devices, e.g., field-effect transistors (OFETs), light-emitting diodes (OLEDs), and photovoltaics (OPVs), all of which consist of multilayer structures...
October 26, 2016: Accounts of Chemical Research
Lei Hu, Jun Chen, Jiale Xu, Na Wang, Fei Han, Yang Ren, Zhao Pan, Yangchun Rong, Rongjin Huang, Jinxia Deng, Laifeng Li, Xianran Xing
The controllable isotropic thermal expansion with a broad coefficient of thermal expansion (CTE) window is intriguing but remains challenge. Herein we report a cubic MZrF6 series (M = Ca, Mn, Fe, Co, Ni and Zn), which exhibit controllable thermal expansion over a wide temperature range and with a broader CTE window (-6.69 to +18.23×10-6/K). In particular, an isotropic zero thermal expansion (ZTE) is achieved in ZnZrF6, which is one of the rarely documented high-temperature isotropic ZTE compounds. By utilizing temperature-dependent high-energy synchrotron X-ray total scattering diffraction, it is found that the flexibility of metal∙∙∙F atomic linkages in MZrF6 plays a critical role in distinct thermal expansions...
October 26, 2016: Journal of the American Chemical Society
Bin Zhu, Yan Jin, Xiaozhen Hu, Qinghui Zheng, Su Zhang, Qianjin Wang, Jia Zhu
A modified poly(dimethylsiloxane) film with nanopores, fabricated through a scalable and low-cost process, can serve as a protective layer for improving lithium-metal anodes. This film can suppress Li-dendrite formation because of its chemical inertness and mechanical properties. Stable cycling over 200 cycles with an averaged CE of 94.5% is demonstrated at 0.5 mA cm(-2) .
October 26, 2016: Advanced Materials
Nataliya Taran, Ludmila Batsmanova, Oksana Kosyk, Oleksandr Smirnov, Mariia Kovalenko, Liubov Honchar, Alexander Okanenko
The use of colloidal solutions of metals as micronutrients enhances plant resistance to unfavorable environmental conditions and ensures high yields of food crops. The purpose of the study was a comparative evaluation of presowing treatment with nanomolybdenum and microbiological preparation impact upon the development of adaptive responses in chickpea plants. Oxidative processes did not develop in all variants of the experiment but in variants treated with microbial preparation, and joint action of microbial and nanopreparations even declined, as evidenced by the reduction of thiobarbituric acid reactive substances in photosynthetic tissues by 15 %...
December 2016: Nanoscale Research Letters
Soo Hyeon Lim, Eun-Young Ahn, Youmie Park
Gold nanoparticles were synthesized using a water extract of Artemisia capillaris (AC-AuNPs) under different extract concentrations, and their catalytic activity was evaluated in a 4-nitrophenol reduction reaction in the presence of sodium borohydride. The AC-AuNPs showed violet or wine colors with characteristic surface plasmon resonance bands at 534~543 nm that were dependent on the extract concentration. Spherical nanoparticles with an average size of 16.88 ± 5.47~29.93 ± 9.80 nm were observed by transmission electron microscopy...
December 2016: Nanoscale Research Letters
Anne E Nigra, Adrian Ruiz-Hernandez, Josep Redon, Ana Navas-Acien, Maria Tellez-Plaza
Published systematic reviews concluded that there is moderate to strong evidence to infer a potential role of lead and cadmium, widespread environmental metals, as cardiovascular risk factors. For other non-essential metals, the evidence has not been appraised systematically. Our objective was to systematically review epidemiologic studies on the association between cardiovascular disease in adults and the environmental metals antimony, barium, chromium, nickel, tungsten, uranium, and vanadium. We identified a total of 4 articles on antimony, 1 on barium, 5 on chromium, 1 on nickel, 4 on tungsten, 1 on uranium, and 0 on vanadium...
October 25, 2016: Current Environmental Health Reports
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