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Jia Wen, Ying Fang, Guangming Zeng
The efficient removal of heavy metals (HMs) from the environment has become an important issue from both biological and environmental perspectives. Recently, porous metal-organic frameworks (MOFs), combining central metals and organic ligands, have been proposed as promising materials in the capture of various toxic substances, including HMs, due to their unique characteristics. Here we review recent progress in the field of water remediation from the perspective of primary HMs (including divalent metals and variable-valent metals) in water pollution and the corresponding MOFs (including virgin and modified MOFs, magnetic MOFs composites and so on) that can remove these metals from water...
March 6, 2018: Chemosphere
Jozef Kováčik, Sławomir Dresler, Petr Babula
Short-term (24 h) responses of Cladonia arbuscula subsp. mitis (formerly known as Cladina and this name is used to distinguish the tested species) and Cladonia furcata to nickel (Ni2+ ) excess (10 or 100 μM) were compared. Cladonia accumulated more Ni at higher Ni dose (1.717 mg total Ni/g DW), K amount was unaffected and Ca amount decreased in Cladina only. Fluorescence microscopy detection of total/general ROS and hydrogen peroxide showed Ni-stimulated increase in both species being more pronounced in Cladonia and in mycobiont partner mainly...
March 6, 2018: Plant Physiology and Biochemistry: PPB
Chao Wang, Zhi-Yi Hu, Heng Zhao, Wenbei Yu, Sijia Wu, Jing Liu, Lihua Chen, Yu Li, Bao-Lian Su
We report three types of conducting polymers (CPs), polyaniline (PANI), polypyrrole (PPY) and poly (3,4-ethylenedioxythiophene) (PEDOT) to modify the surface of the CdS nanorods to probe their photocorrosion inhibition and photocatalytic hydrogen production. Various characterizations, such as high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV) and density function theory (DFT) calculations have been conducted to reveal the intrinsic structure of the as-constructed CPs@CdS (@ means CPs at the surface of CdS) core-shell nanorods...
March 6, 2018: Journal of Colloid and Interface Science
Pouyan Ebrahimi, Javier Vilcáez
This research aimed to elucidate the effect of brine salinity and guar gum on the sorption and transport of Ba in dolomite rocks collected from the Arbuckle formation in Oklahoma, USA. Guar gum represents the most important organic additive used in viscosified fracturing fluids, and Ba constitutes the most common and abundant heavy metal found in unconventional oil and gas (UOG) wastewater. Batch experiments conducted using powdered dolomite rocks (500-600 μm particle size) revealed that at brine salinities of UOG wastewater, chloro-complexation reactions between Ba and Cl ions and pH changes that results from dolomite dissolution are the controlling factors of Ba sorption on dolomite...
March 12, 2018: Journal of Environmental Management
Haibin Zhou, Haibo Meng, Lixin Zhao, Yujun Shen, Yueqing Hou, Hongsheng Cheng, Liqiu Song
In this study, two different biochars (sawdust charcoal (SDC) and wheat straw charcoal (WSC)) and biological humic acid (BHA) were used with different addition rates in pig manure composting to illustrate the effect on heavy metals passivation. And the composts were applied to rape (Brassica campestris L.) growth to illustrate the stability of the passivation. Results showed the concentration of Cu, Cd, and Pb increased after composting, whereas the passivation rates of Cu, Pb, and Cd reached a maximum of 94...
February 23, 2018: Bioresource Technology
Pavel Gushchin, Valentina A Lyubimenko, Evgenii V Ivanov, Sergey I Kolesnikov, Daria A Petrova, Vladimir A Vinokurov, Ivan M Kolesnikov
The thermodynamic calculation of the optimal composition of the oxide catalysts with different natures is performed based on the theory of catalysis by polyhedra. The obtained compositions of the active catalysts are in keeping with the experimental data. The electrostatic potential generated by polyhedrons of metal oxide catalysts in a variety of directions is calculated. The dependence of the sign and magnitude of the potential on the distance from the central metal ion towards the vertex of the polyhedron, the middle of its edge or the centre of the face is estimated...
March 15, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Barry M Trost, Chris Kalnmals
Herein, we report a valuable umpolung strategy that highlights the ambiphilic nature of the bis(phenylsulfonyl)methyl synthon and demonstrates its utility as a synthetic linchpin. While the bis(phenylsulfonyl)methyl group is typically introduced as an sp3 carbon nucleophile, we demonstrate that it can also function as an effective sp2 carbon electrophile in the presence of organolithium nucleophiles. Akyl- and aryllithiums couple with the central carbon of the bis(phenylsulfonyl)methyl unit to ultimately generate trisubstituted alkenes, comprising a formal sp3-sp2 and sp2-sp2 cross-coupling between organolithiums and bis(sulfones)...
March 15, 2018: Chemistry: a European Journal
Stefan Ilic, Abdulaziz Alherz, Charles B Musgrave, Ksenija D Glusac
Metal-free hydrides are of increasing research interest due to their roles in recent scientific advances in catalysis, such as hydrogen activation with frustrated Lewis pairs and electrocatalytic CO2 reduction with pyridinium and other aromatic cations. The structural design of hydrides for specific applications necessitates the correct description of their thermodynamic and kinetic prowess using reliable parameters - thermodynamic hydricity (ΔGH-) and nucleophilicity (N). This review summarizes reported experimental and calculated hydricity values for more than 200 metal-free hydride donors, including carbon-, boron-, nitrogen- and silicon-based hydrides...
March 15, 2018: Chemical Society Reviews
Bruno Tochetto Primo, Leonardo Marcos Mezzari, Luís Carlos da Fontoura Frasca, Raquel Linderman, Elken Gomes Rivaldo
PURPOSE: To evaluate and compare the clinical and radiographic outcomes of mandibular rehabilitation with fixed prostheses on three implants with immediate versus delayed loading. MATERIALS AND METHODS: The sample comprised 21 patients who underwent treatment with immediate loading and 23 who received delayed loading. All had worn their prostheses for at least 18 months. Radiographic evaluation of bone loss was carried out in Adobe Photoshop CS5 by a single calibrated examiner using digitized panoramic radiographs...
March 15, 2018: International Journal of Oral & Maxillofacial Implants
Seungtaik Hwang, Arun Gopalan, Maximilian Hovestadt, Frank Piepenbreier, Christian Chmelik, Martin Hartmann, Randall Q Snurr, Jörg Kärger
Molecular diffusion is commonly found to slow down with increasing molecular size. Deviations from this pattern occur in some host materials with pore sizes approaching the diameters of the guest molecules. A variety of theoretical models have been suggested to explain deviations from this pattern, but robust experimental data are scarcely available. Here, we present such data, obtained by monitoring the chain length dependence of the uptake of n- alkanes in the zeolitic imidazolate framework ZIF-4. A monotonic decrease in diffusivity from ethane to n- butane was observed, followed by an increase for n- pentane, and another decrease for n- hexane...
March 15, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Bin Peng, Wei Zheng, Jiantao Qin, Wanli Zhang
Two-dimensional transitional metal dichalcogenide (TMDC) field-effect transistors (FETs) are proposed to be promising for devices scaling beyond silicon-based devices. We explore the different effective mass and bandgap of the channel materials and figure out the possible candidates for high-performance devices with the gate length at 5 nm and below by solving the quantum transport equation self-constantly with the Poisson equation. We find that out of the 14 compounds, MoS₂, MoSe₂, and MoTe₂ may be used in the devices to achieve a good subthreshold swing and a reasonable current ON-OFF ratio and delay...
March 15, 2018: Materials
Nils Große Hokamp, Alexandra Hellerbach, Andreas Gierich, David W Jordan, Veerle Visser-Vandewalle, David Maintz, Stefan Haneder
OBJECTIVES: The aim of this study was to evaluate the reduction of artifacts from deep brain stimulation electrodes (DBS) using an iterative metal artifact reduction algorithm (O-MAR), virtual monoenergetic images (VMI), and both in combination in postoperative spectral detector computed tomography using a dual-layer detector (spectral detector computed tomography [SDCT]) of the head. MATERIAL AND METHODS: Nonanthropomorphic phantoms with different DBS leads were examined on SDCT; in 1 phantom periprocedural bleeding was simulated...
March 14, 2018: Investigative Radiology
Annika Selvick, Rita Lloyd
The Nuss procedure has become the predominant reason for the use of metal implants by pediatric general and thoracic surgeons. Current guidelines recommend preimplant testing for all patients undergoing the Nuss procedure, which differs from the guidelines for all other orthopedic procedures. This review was done to further evaluate this discrepancy.
February 28, 2018: Dermatitis
Andreu Presa, Guillem Vázquez, Leoní A Barrios, Olivier Roubeau, Luís Korrodi-Gregório, Ricardo Pérez-Tomás, Patrick Gamez
The development of photoactivatable metal complexes with potential anticancer properties is a topical area of current investigation. Photoactivated chemotherapy using coordination compounds is typically based on photochemical processes occurring at the metal center. In the present study, an innovative approach is applied that takes advantage of the remarkable photochemical properties of diarylethenes. Following a proof-of-concept study with two complexes, namely, C1 and C2, a series of additional platinum(II) complexes from dithienylcyclopentene-based ligands was designed and prepared...
March 15, 2018: Inorganic Chemistry
Tao Jiang, Hao Hong, Can Liu, Wei-Tao Liu, Kaihui Liu, Shiwei Wu
Interactions between elementary excitations, such as carriers, phonons and plasmons, are critical for understanding the optical and electronic properties of materials. The significance of these interactions is more prominent in low-dimensional materials and can dominate their physical properties due to the enhanced interactions between these excitations. One-dimensional single-walled carbon nanotubes provide an ideal system for studying such interactions due to their perfect physical structures and rich electronic properties...
March 15, 2018: Nano Letters
Qing Li, Biao Yang, Jonas Björk, Qigang Zhong, Huanxin Ju, Junjie Zhang, Nan Cao, Ziliang Shi, Haiming Zhang, Daniel Ebeling, Andre Schirmeisen, Junfa Zhu, Lifeng Chi
Hierarchical control of chemical reactions is being considered as one of the most ambitious and challenging topics in modern organic chemistry. In this study, we have realized the one-by-one scission of the X-H bonds (X=N and C) of aromatic amines in a controlled fashion on the Cu(111) surface. Each dehydrogenation reaction leads to certain metal-organic supramolecular structures, which were monitored in single-bond resolution via scanning tunneling microscopy and non-contact atomic force microscopy. Moreover, the reaction pathways were elucidated from X-ray photoelectron spectroscopy measurements and density functional theory calculations...
March 15, 2018: Journal of the American Chemical Society
Andy A Thomas, Andrew F Zahrt, Connor P Delaney, Scott E Denmark
The Suzuki-Miyaura reaction is the most practiced palladium-catalyzed, cross-coupling reaction because of its broad applicability, low toxicity of the metal (B), and the wide variety of commercially available boron substrates. A wide variety of boronic acids and esters, each with different properties, have been developed for this process. Despite the popularity of the Suzuki-Miyaura reaction, the precise manner in which the organic fragment is transferred from boron to palladium has remained elusive for these reagents...
March 15, 2018: Journal of the American Chemical Society
Vahid Mirshafiee, Bingbing Sun, Chong Hyun Chang, Yu-Pei Liao, Wen Jiang, Jinhong Jiang, Xiangsheng Liu, Xiang Wang, Tian Xia, Andre E Nel
The liver and the mononuclear phagocyte system (MPS) is a frequent target for engineered nanomaterials (ENMs), either as a result of particle uptake and spread from primary exposure sites or systemic administration of therapeutic and imaging nanoparticles. In this study, we performed a comparative analysis of the toxicological impact of 29 metal oxide (MOx) nanoparticles (NPs), some commonly used in consumer products, in transformed or primary Kupffer cells (KCs) and hepatocytes. Not only did we observe differences between KC and hepatocytes, but also differences in the toxicological profiles of transition metal oxides (TMOs, e...
March 15, 2018: ACS Nano
Maiko K Okajima, Saranyoo Sornkamnerd, Tatsuo Kaneko
Cyanobacteria are regarded as very eco-friendly microreactors for the production of various biomolecules such as polysaccharides by fixing not only carbon but also nitrogen in water. Cyanobacterial polysaccharides having various functional groups such as hydroxyls, carboxyls, sulfates, etc. have the ability to interact with metals or inorganics, to create bionanocomposites. Sacran, a supergiant cyanobacterial anionic polysaccharide extracted from the extracellular matrix of Aphanothece sacrum which is mass-cultivated in freshwater, is mainly used to create functional bionanocomposites...
March 15, 2018: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
Nika Mahne, Sara E Renfrew, Bryan D McCloskey, Stefan A Freunberger
Solid alkaline carbonates are universal passivation layer components of intercalation battery materials, common side products in metal-O₂ batteries, and are believed to form and decompose reversibly in metal-O₂/CO₂ cells. In all of these cathode chemistries, Li₂CO₃ decomposes to CO₂ when exposed to potentials >3.8 V vs. Li/Li+. Notably, though, O₂ evolution is not detected, as is expected according to the decomposition reaction 2 Li₂CO₃ → 4 Li+ + 4 e- + 2 CO₂ + O₂. O-moieties were therefore previously considered unaccounted for in unidentified parasitic reactions...
March 15, 2018: Angewandte Chemie
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