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Metal on metal

Lili Pan, Jianteng Sun, X Chris Le, Lizhong Zhu
Contamination of organic pollutants in the environment is usually accompanied by heavy metals. However, a little information on the influences of heavy metals on the uptake, translocation and transformation of organic pollutants in plants is available. In this study, ten-day hydroponic exposure was conducted to explore the influence of copper (Cu) on the bioaccumulation and biotransformation of polychlorinated biphenyls (PCBs) in intact young rice (Oryza sativa L.). Low dose of Cu (≤100 μmol/L) increased the accumulation of CB-61 in rice plants, while excess concentrations of Cu (>100 μmol/L) inhibited uptake and translocation of CB-61...
November 13, 2017: Chemosphere
Gokhan Zengin, Dimitrina Zheleva-Dimitrova, Reneta Gevrenova, Paraskev Nedialkov, Andrei Mocan, Ana Ćirić, Jasmina Glamočlija, Marina Soković, Abdurrahman Aktumsek, M Fawzi Mahomoodally
The Centaurea genus has great potential in traditional systems and has attracted much interest in the design of novel drug formulations. The present study was focused on the chemical fingerprints and biological properties of Centaurea drabifolia subsp. drabifolia and Centaurea lycopifolia extracts. Spectrophotometric and LC-MS techniques were used to establish the chemical profiles of the studied extracts. Enzyme inhibitory potential was assessed against key enzymes linked to global health problems, namely neurodegenerative diseases (acetylcholinesterase), pigmentation (tyrosinase), and diabetes (α-amylase and α-glucosidase)...
November 20, 2017: Journal of Pharmaceutical and Biomedical Analysis
Ana Luísa Maulvault, Carolina Camacho, Vera Barbosa, Ricardo Alves, Patrícia Anacleto, Fabiola Fogaça, Christiaan Kwadijk, Michiel Kotterman, Sara C Cunha, José O Fernandes, Rie R Rasmussen, Jens J Sloth, Òscar Aznar-Alemany, Ethel Eljarrat, Damià Barceló, António Marques
Emerging chemical contaminants [e.g. toxic metals speciation, flame retardants (FRs) and perfluorinated compounds (PFCs), among others], that have not been historically recognized as pollutants nor their toxicological hazards, are increasingly more present in the marine environment. Furthermore, the effects of environmental conditions (e.g. temperature and pH) on bioaccumulation and elimination mechanisms of these emerging contaminants in marine biota have been poorly studied until now. In this context, the aim of this study was to assess, for the first time, the effect of warmer seawater temperatures (Δ = + 4°C) and lower pH levels (Δ = - 0...
November 20, 2017: Environmental Research
Ying Li, Cheng Chen, Yao Wu, Yijie Han, Yeqing Lan
The synergism of CuS and tartaric acid (TA) in the reduction of Cr(VI) with an irradiation of simulated solar light was investigated through observing the effects of solution pH, temperature, CuS loading, and TA concentration on the removal efficiency of Cr(VI). Approximately 32% and 54% of the initial Cr(VI) (100 µmol/L) were reduced within 180 min by TA and CuS with light, respectively. Under the same condition, however, almost a complete removal of the initial Cr(VI) was achieved within 130 min in the coexistence of CuS and TA...
November 23, 2017: Environmental Technology
Chandra M Richards, Jasper L Van Puffelen, CéLine Pallud
Bar-built estuaries are unique ecosystems characterized by the presence of a sandbar barrier, which separates the estuary from the ocean for extended periods and that can naturally reopen to the ocean with heavy rainfall and freshwater inflows. The physical effects associated with the transition from closed to open state, specifically water mixing and sediment resuspension, often indirectly worsen water quality conditions and are suspected to drive near-annual fish kills at the Pescadero Estuary in northern California...
November 23, 2017: Environmental Toxicology and Chemistry
Changhang Xu, Jing Xie, Wuyang Zhang, Qingzhao Kong, Guoming Chen, Gangbing Song
Vibrothermography often employs a high-power actuator to generate heat on a specimen to reveal damage, however, the high-power actuator brings inconvenience to the application and possibly introduces additional damage to the inspected objects. This study uses a low-power piezoceramic transducer as the actuator of vibrothermography and explores its ability to detect multiple surface cracks in a metal part. Experiments were conducted on a thin aluminum beam with three cracks in different orientations. Detailed analyses of both thermograms and temperature data are presented to validate the proposed vibrothermography method...
November 23, 2017: Sensors
Ayla Uysal, Dilara Tuncer, Esengul Kir, Tugba Sardohan Koseoglu
In this study, the effects of the combination of acid hydrolysis and Donnan dialysis on the high-quality struvite production from digested sewage sludge were examined. The Box-Behnken design was applied in the hydrolysis using oxalic acid for the optimization of the conditions that affect the nutrients and metal release from digested sludge. An optimal condition was obtained at oxalic acid 0.5 M, acid/sludge ratio (mL/g) 10/1, and reaction time 60 min. The separation of the metals from hydrolyzed sludge liquid was carried out with the Donnan dialysis using a Nafion 117 cation exchange membrane...
November 2017: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Natalia Sizochenko, Alicja Mikolajczyk, Karolina Jagiello, Tomasz Puzyn, Jerzy Leszczynski, Bakhtiyor Rasulev
Application of predictive modeling approaches can solve the problem of missing data. Numerous studies have investigated the effects of missing values on qualitative or quantitative modeling, but only a few studies have discussed it for the case of applications in nanotechnology-related data. The present study is aimed at the development of a multi-nano-read-across modeling technique that helps in predicting the toxicity of different species such as bacteria, algae, protozoa, and mammalian cell lines. Herein, the experimental toxicity of 184 metal and silica oxide (30 unique chemical types) nanoparticles from 15 datasets is analyzed...
November 23, 2017: Nanoscale
Tao Hu, Jinxing Yang, Xiaohui Wang
Carbon vacancies are commonly present in two-dimensional (2D) MXenes that hold promise in a variety of applications whereas their behavior remains unknown. Here we report on the influence of carbon vacancies on the structural stability, electronic properties and stiffness of MXenes by taking Ti2CT2 (T = O, F, and OH) as an example. According to the first-principles calculations, the formation energies of carbon vacancies in MXenes are lower than those in other typical 2D materials including graphene and MoS2, in combination with high migration energies...
November 23, 2017: Physical Chemistry Chemical Physics: PCCP
Yuqi Zhu, Ruiping Zhou, Feng Zhang, Joerg Appenzeller
Based on the careful design of two-terminal devices from multi-layer transition metal dichalcogenides (TMDs) such as MoS2 and WSe2, truly vertical transport has been experimentally evaluated and theoretically analyzed. By exploring, the electric field and temperature dependence of in total 28 TMD devices of various thicknesses, a model that describes vertical transport as Fowler Nordheim mediated at high electric fields and thermal injection dominated at low fields has been developed. Our approach is similar to the description chosen to capture gate leakage current levels through amorphous materials such as SiO2...
November 23, 2017: Nanoscale
Ki Chul Kim, David Fairen-Jimenez, Randall Q Snurr
A thermodynamic analysis using quantum chemical methods was carried out to identify optimal functional group candidates that can be included in metal-organic frameworks and activated carbons for the selective capture of toxic industrial chemicals (TICs) in humid air. We calculated the binding energies of 14 critical TICs plus water with a series of 10 functional groups attached to a naphthalene ring model. Using vibrational calculations, the free energies of adsorption were calculated in addition to the binding energies...
November 23, 2017: Physical Chemistry Chemical Physics: PCCP
Arunasis Bhattacharyya, Richard J M Egberink, Prasanta K Mohapatra, Parveen K Verma, Ashok K Yadav, Sambhunath Jha, Dibyendu Bhattacharyya, Jurriaan Huskens, Willem Verboom
This paper reports the solvent extraction of Am(3+) and Eu(3+) using N,N,N',N',N'',N''-hexa-n-octylnitrilotriacetamide (HONTA) as the extractant in n-dodecane. The results are in variance with those reported previously with respect to the nature of the extracted species. The solvent extraction data were entirely different from those reported previously as the extracted species conformed to 1 : 2 (M : L) species for both Am(3+) and Eu(3+) ions. The structure of the extracted complex was determined by EXAFS demonstrating the three amidic 'O' atoms of the HONTA complex with the Eu(3+) ion...
November 23, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Joseph A B Abdalla, Alexa Caise, Christian P Sindlinger, Rémi Tirfoin, Amber L Thompson, Alison J Edwards, Simon Aldridge
Bond activation at a transition metal centre is a key fundamental step in numerous chemical transformations. The oxidative addition of element-hydrogen bonds, for example, represents a critical step in a range of widely applied catalytic processes. Despite this, experimental studies defining steps along the bond activation pathway are very rare. In this work, we report on fundamental studies defining a new oxidative activation pathway: combined experimental and computational approaches yield structural snapshots of the simultaneous activation of both bonds of a β-diketiminate-stabilized GaH2 unit at a single metal centre...
December 2017: Nature Chemistry
Xuyang Sun, Zhi-Zhu He, Zhong-Shan Deng, Yi-Xin Zhou, Jing Liu
BACKGROUND: Radio-frequency ablation has been an important physical method for tumor hyperthermia therapy. The conventional rigid electrode boards are often uncomfortable and inconvenient for performing surgery on irregular tumors, especially for those tumors near the joints, such as ankles, knee-joints or other facets like finger joints. MATERIAL AND METHODS: We proposed and demonstrated a highly conformable tumor ablation strategy through introducing liquid metal bath as conformable soft electrodes...
November 23, 2017: Minimally Invasive Therapy & Allied Technologies: MITAT
Jin-Yue Zeng, Xiao-Shuang Wang, Mingkang Zhang, Zi-Hao Li, Dan Gong, Pei Pan, Lin Huang, Si-Xue Cheng, Han Cheng, Xian-Zheng Zhang
A universal strategy was reported that enables functional group-capped nanostructures with various morphologies and compositions to be coated by porphyrin metal-organic framework (MOF). Based on nanostructure-induced heterogeneous nucleation, the controlled growth of MOF shell on the surface of nanostructures can be realized. It was demonstrated that this modification strategy can realize controlled growth of porphyrin MOF on a series of organic and inorganic nanostructures, such as polydopamine (PDA) nanoparticles, PDA@Pt nanoparticles, graphene oxide (GO) sheets and Au nanorods (AuNR)...
November 23, 2017: ACS Applied Materials & Interfaces
Itziar Bonilla-Del Rίo, Nagore Puente, Sara Peñasco, Irantzu Rico, Ana Gutiérrez-Rodrίguez, Izaskun Elezgarai, Almudena Ramos, Leire Reguero, Inmaculada Gerrikagoitia, Brian R Christie, Patrick Nahirney, Pedro Grandes
Cannabinoid type-1 (CB1 ) receptors are widely distributed in the brain and play important roles in astrocyte function and the modulation of neuronal synaptic transmission and plasticity. However, it is currently unknown how CB1 receptor expression in astrocytes is affected by long-term exposure to stressors. Here we examined CB1 receptors in astrocytes of ethanol (EtOH)-exposed adolescent mice to determine its effect on CB1 receptor localization and density in adult brain. 4-8-week-old male mice were exposed to 20 percent EtOH over a period of 4 weeks, and receptor localization was examined after 4 weeks in the hippocampal CA1 stratum radiatum by pre-embedding immunoelectron microscopy...
November 23, 2017: Addiction Biology
Aurélie Pelfrêne, Francis Douay
Soil and dust contamination by metals engenders significant environmental and health problems in northern France where a lead smelter was in activity for more than a century. This study aims to examine the long-term effects of the smelter, 10 years after its closedown, on the presence of metal in sidewalk dust for a better assessment of the local population's exposure to Cd and Pb. The investigation included: (i) the metal distribution in different dust particle sizes and (ii) the assessment of metal bioaccessibility via ingestion and inhalation of dust...
November 22, 2017: Environmental Science and Pollution Research International
Bixi Guo, Yongqin Liu, Fan Zhang, Juzhi Hou, Hongbo Zhang, Chaoliu Li
Heavy metal contamination has affected many regions in the world, particularly the developing countries of Asia. We investigated 8 heavy metals (Cu, Zn, Cd, Pb, Cr, Co, Ni, and As) in the surface sediments of 18 lakes on the Tibetan Plateau. It was found that the distributions of the heavy metals showed no clear spatial pattern on the plateau. The results indicated that the mean concentrations of these metals in the sediment samples diminished as follows: Cr > As > Zn > Ni > Pb > Cu > Co > Cd...
November 22, 2017: Environmental Science and Pollution Research International
Yuji Furutani
An understanding of ion-protein interactions is key to a better understanding of the molecular mechanisms of proteins, such as enzymes, ion channels, and ion pumps. A potassium ion channel, KcsA, has been extensively studied in terms of ion selectivity. Alkali metal cations in the selectivity filter were visualized by X-ray crystallography. Infrared spectroscopy has an intrinsically higher structural sensitivity due to frequency changes in molecular vibrations interacting with different ions. In this review article, I attempt to summarize ion-exchange-induced differences in Fourier transform infrared spectroscopy, as applied to KcsA, to explain how this method can be utilized to study ion-protein interactions in the KcsA selectivity filter...
November 22, 2017: Biophysical Reviews
Chang Liu, De Zhang, Yumin Liu, Dong Wu, Lei Chen, Rui Ma, Zhongyuan Yu, Li Yu, Han Ye
We propose and theoretically investigate an efficient solar light absorber based on a multilayer structure consisting of tungsten nanoparticle layers and SiO2 layers. According to our calculation, average absorbance over 94% is achieved in the wavelength range between 400 and 2500 nm for the proposed absorber. The excellent performance of the absorber can be attributed to the localized surface plasmon resonance as well as the Fabry-Perot resonance among the metal-dielectric-metal layers. We compare the absorbing efficiency of tungsten nanosphere absorber with absorbers consisting of the other metal nanoparticles and conclude that iron can be an alternative material for tungsten in solar energy systems for its excellent absorbing performance and the similar optical properties as tungsten...
November 22, 2017: Nanoscale Research Letters
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