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Xiong Li, Hang Li, Gang Yang
Electric fields exist ubiquitously in chemical and biological systems while how to affect the interfacial adsorption processes remain elusive. Here, molecular dynamics simulations are used to understand at a molecular level the adsorption of metal ions at the interface of aqueous solutions and clay materials that are generally endowed with strong electric fields. In absence of electric fields, even Cs(+), one of the strongest adsorbed metal ions, is facile to detach from solvated clay surfaces. Electric fields are critical to construct stable inner-sphere complexes and enhance pronouncedly the adsorption strengths of both inner- and outer-sphere complexes...
April 13, 2017: Journal of Colloid and Interface Science
A Bianco, M I Polo López, P Fernández Ibáñez, M Brigante, G Mailhot
In this study, the activation of H2O2 and persulfate ions induced by solar photolysis of Fe(III)EDDS complex were investigated in water disinfection, applying solar AOPs processes. The use of Fe(III)EDDS complex maintains iron in soluble form until slightly basic pH and so the photolysis is efficient in a large range of pH compatible with natural waters. Moreover, for the first time, the impact of photogenerated hydroxyl and sulfate radicals on the inactivation of Enterococcus faecalis in water was studied...
April 18, 2017: Water Research
Wen-Sheng Zou, Qing-Chun Zhao, Jun Zhang, Xiao-Ming Chen, Xiu-Fang Wang, Lin Zhao, Shao-Hua Chen, Ya-Qin Wang
Whether as an important biological element or as a radioactive source/medicine, the monitoring of trace levels of cobalt ions (Co) has become a non-negligible factor for human health and green environment. Current technologies for the detection of Co are cost-expensive and time-consuming, and require cumbersome sample pretreatment process. Herein a novel sensing platform has been developed for Co detection based on the quenching of the enhanced fluorescence signal of polyamine functionalized C-dots. Amine groups at the surface of the C-dots can capture Zn(2+)/Cd(2+) to form coordination compound, which can inhibit the photoinduced electron transfer pathways of C-dots and then induce the fluorescence enhancement of the C-dots by ∼80% margin...
June 1, 2017: Analytica Chimica Acta
Yang Gao, Xuemei Ren, Xiaoli Tan, Tasawar Hayat, Ahmed Alsaedi, Changlun Chen
The effects of pH, cations (Na(+), K(+), Mg(2+), Ca(2+) and Al(3+)), and anions (Cl(-), HCO3(-), HPO4(2-) and SO4(2-)) on graphene oxide (GO) stability were investigated to address the current limitations in the knowledge regarding the stability of GO in natural surface water and its underlying mechanism. The threshold values of cations that destabilize GO were obtained and affected by both pH and anions. By employing elemental mapping and studying the effects of polyacrylic acid (PAA) on GO sedimentation and the re-dispersion of GO aggregates, we find that the GO aggregates induced by Na(+) and K(+) via electric double layer suppression and by Ca(2+) and Al(3+) via strong complxing are difficult to re-disperse completely...
April 11, 2017: Journal of Hazardous Materials
Koji Oohora, Ning Tang, Yoshitsugu Morita, Takashi Hayashi
Horseradish peroxidase was reconstituted with cobalt tetradehydrocorrin, rHRP(Co(TDHC)), as a structural analog of cobalamin coordinated with an imidazolate-like His residue, which is generally seen in native enzymes. In contrast to the previously reported cobalt tetradehydrocorrin-reconstituted myoglobin, rMb(Co(TDHC)), the HRP matrix was expected to provide strong axial ligation by His170 which has imidazolate character. rHRP(Co(II)(TDHC)) was characterized by EPR and its reaction with reductants indicates a negative shift of its redox potential compared to rMb(Co(TDHC))...
April 21, 2017: Journal of Biological Inorganic Chemistry: JBIC
Yang Liu, Yongzhen Yang, Xuzhen Wang, Yanfeng Dong, Yongchao Tang, Zhengfa Yu, Zongbin Zhao, Jieshan Qiu
Ultrafine SnS2 nanocrystals/reduced graphene oxide nanoribbon paper (SnS2/RGONRP) has been created by a well-designed process including in situ reduction, evaporation induced self-assembly and sulfuration. The as formed SnS2 nanocrystals possess an average diameter of 2.3 nm and disperse on the surface of RGONRs uniformly. The strong capillary force formed during evaporation leads to a compact assembly of RGONRs to give flexible paper structure with high density of 0.94 g cm-3. The as-prepared SnS2/RGONRP composite could be directly used as free-standing electrode for sodium ion batteries...
April 21, 2017: ACS Applied Materials & Interfaces
Andreas Meyer, Tomas Slanina, Alexander Heckel, Burkhard König
Metal ions can have beneficial effects on photoinduced electron transfer. Merging such metal-ion coupled electron transfer (MCET) with consecutive photoinduced electron transfer (conPET) enables the one-electron reduction of chlorobenzene with blue light in the presence of diisopropylethylamine as electron donor. The presence of the metal ions extends the substrate scope of the photoredox catalysis to extreme reduction potentials (beyond -3 V vs SCE).
April 21, 2017: Chemistry: a European Journal
Dayne C Georgiou, Mohammad A Haghighatbin, Conor F Hogan, Michael S Scholz, James N Bull, Evan J Bieske, David J D Wilson, Jason L Dutton
We report the first example of an alkene with two carbon-bound substituents (imidazole and imidazolium rings) where the Z-isomer has a greater thermodynamic stability than the E-isomer which persists in both the gas phase and in solution. Theoretical calculations, solution fluorescence spectroscopy and gas-phase ion mobility mass spectrometry studies confirm the preference for the Z-isomer, the stability of which is traced to a non-covalent interaction between the imidazole lone pair and the imidazolium ring...
April 21, 2017: Angewandte Chemie
A Yaroshchuk, E E Licón, E K Zholkovskiy, M P Bondarenko, T Heldal
To have non-zero net flow in AC electroosmotic pumps, the electroosmosis (EO) has to be non-linear and asymmetric. This can be achieved due to ionic concentration polarization. This is known to occur close to micro-/nano-interfaces provided that the sizes of the nanopores are not too large compared to the Debye screening length. However, operation of the corresponding EO pumps can be quite sensitive to the solution concentration and, thus, unstable in practical applications. Concentration polarization of ion-exchange membranes is much more robust...
April 21, 2017: Faraday Discussions
Masashi Nakamura, Takahiro Banzai, Yuto Maehata, Osamu Endo, Hiroo Tajiri, Osami Sakata, Nagahiro Hoshi
Understanding the electrocrystallization mechanisms of metal cations is of importance for many industrial and scientific fields. We have determined the transitional structures during underpotential deposition (upd) of various metal cations on Au(111) electrode using time-resolved surface X-ray diffraction and step-scan IR spectroscopy. At the initial stage of upd, a characteristic intensity transient appears in the time-resolved crystal truncation rod depending on metal cations. Metal cations with relatively high coordination energies of hydration water are deposited in two steps: first, the hydrated metal cations approached the surface and are metastably located at the outer Helmholtz plane, then they are deposited via the destruction of the hydration shell...
April 20, 2017: Scientific Reports
Oualid Hamdaoui, Slimane Merouani
In this paper, the effect of periodate (IO4(-)) on the ultrasonic degradation at 300kHz of Brilliant Blue R (BBR), an organic dye pollutant, was investigated. The experiments were realized in the absence and presence of periodate for various operating conditions including initial solution pH (2-8) and delivered ultrasonic power (20-80W). It was found that periodate greatly enhanced the sonochemical degradation of BBR. The degradation rate increased significantly with increasing IO4(-) concentration up to 10mM and decreased afterward...
July 2017: Ultrasonics Sonochemistry
Julie A Korak, Richard Huggins, Miguel Arias-Paic
Due to stricter regulations, some drinking water utilities must implement additional treatment processes to meet potable water standards for hexavalent chromium (Cr(VI)), such as the California limit of 10 μg/L. Strong base anion exchange is effective for Cr(VI) removal, but efficient resin regeneration and waste minimization are important for operational, economic and environmental considerations. This study compared multiple regeneration methods on pilot-scale columns on the basis of regeneration efficiency, waste production and salt usage...
March 9, 2017: Water Research
Haoyang Zhang, Wenkui Wu, Chao Feng, Zhaogang Liu, Enhe Bai, Xueyuan Wang, Meng Lei, Hao Cheng, Huayun Feng, Jingmiao Shi, Jia Wang, Zhao Zhang, Tao Jin, Shanshan Chen, Shihe Hu, Yongqiang Zhu
Based upon the modeling binding mode of marketed AZD9291 with T790M, a series of 5,6-dihydro-4H-pyrrolo[3,2,1-ij]quinoline derivatives were designed and synthesized with the purpose to overcome the drug resistance resulted from T790M/L858R double mutations. The most potent compound 8 showed excellent enzyme inhibitory activities and selectivity with sub nanomolar IC50 values for both the single L858R and double T790M/L858R mutant EGFRs, and was more than 8-fold selective for wild type EGFR. Compound 8 exhibited good microsomes stabilities and pharmacokinetic properties and lower binding affinity to hERG ion channel than AZD9291 and displayed strong antiproliferative activity against the H1975 non-small cell lung cancer (NSCLC) cells bearing T790M/L858R and in vivo anticancer efficacy in a human NSCLC (H1975) xenograft mouse model...
April 14, 2017: European Journal of Medicinal Chemistry
Dengpan Dong, Justin B Hooper, Dmitry Bedrov
Understanding the behavior of aqueous solutions containing tetra-alkyl ammonium (TAA) cations is of great significance in a number of applications, including polymer membranes for fuel cells. In this work, a polarizable force field has been used to preform atomistic molecular dynamics (MD) simulations of aqueous solutions containing tetra-methyl ammonium (TMA) or tetra-butyl ammonium (TBA) cations and Br counterions. Extensive MD simulations of TMA-Br/water and TBA-Br/water systems were conducted as a function of solution composition (ion pair : water molar ratios of 1:10, 1:20, 1:30, 1:63, 1:500) at atmospheric pressure and 298K...
April 20, 2017: Journal of Physical Chemistry. B
Soumava Biswas, Jayita Chakraborty, Vijay Singh Parmar, Siba Prasad Bera, Nirmal Ganguli, Sanjit Konar
Two new lanthanide-based 3D metal-organic frameworks (MOFs), {[Ln(L)(Ox)(H2O)]n·xH2O} [Ln = Gd(3+) and x = 3 (1) and Dy(3+) and x = 1.5 (2); H2L = mucic acid; OxH2 = oxalic acid] showing interesting magnetic properties and channel-mediated proton conduction behavior, are presented here. Single-crystal X-ray structure analysis shows that, in complex 1, the overall structure originates from the mucate-bridged gadolinium-based rectangular metallocycles. The packing view reveals the presence the two types of hydrophilic 1D channels filled with lattice water molecules, which are strongly hydrogen-bonded with coordinated water along the a and b axes, whereas for complex 2, the 3D framework originates from a carboxylate-bridged dysprosium-based criss-cross-type secondary building block...
April 20, 2017: Inorganic Chemistry
Yu Zhang, Yanshan Huang, Guanhui Yang, Fanxing Bu, Ke Li, Imran Shakir, Yuxi Xu
Polymer cathode materials are promising alternatives to inorganic counterparts for both lithium ion batteries (LIBs) and sodium ion batteries (SIBs) due to their high theoretical capacity, adjustable molecular structure and strong adaptability to different counter-ions in batteries, etc. However, they suffer from poor practical capacity and low rate capability because of their intrinsically poor conductivity. Herein, we report the synthesis of self-assembled graphene/poly(anthraquinonyl sufide) (PAQS) composite aerogel (GPA) with efficient integration of three-dimensional (3D) graphene framework with electroactive PAQS particles via a novel dispersion-assembly strategy, which can be used as a free-standing flexible cathode upon mechanical pressing...
April 20, 2017: ACS Applied Materials & Interfaces
Matthias Franke, Daniel Wechsler, Quratulain Tariq, Michael Röckert, Liang Zhang, Pardeep Kumar Thakur, Nataliya Tsud, Sofiia Bercha, Kevin Prince, Tien-Lin Lee, Hans-Peter Steinrück, Ole Lytken
We have investigated the interactions between cobalt(ii)-tetraphenylporphyrin (CoTPP) molecules and MgO(100) thin films on Ag(100) by means of Synchrotron Radiation X-Ray and Ultra-Violet Photoelectron Spectroscopy (SR-XPS and SR-UPS). At room temperature, the CoTPP monolayer consists of two different species. A minority of molecules exhibits a strong electronic interaction with the substrate, whereas for the majority a similar spectroscopic signature as for multilayer molecules is observed. Based on the lateral inhomogeneity of the surface electronic structure, we tentatively suggest that the strongly interacting molecules adsorb with their metal center directly above oxygen ions...
April 20, 2017: Physical Chemistry Chemical Physics: PCCP
Wenjun Wu, Huaide Xiang, Wei Fan, Jinglin Wang, Haifeng Wang, Xin Hua, Zhaohui Wang, Yi-Tao Long, He Tian, Wei-Hong Zhu
Up to date, development of organic sensitizers has been predominately focused on light harvesting, HOMO and LUMO energy levels, and electron transferring process. In contrast, their adsorption mode as well as dynamic loading behaviour onto nanoporous TiO2 is rarely considered. Herein we have employed the time of flight secondary ion mass spectrometry (TOF-SIMS) to take insight into the competitive dye adsorption mode and kinetics in cosensitized porphyrin system. Using the novel porphyrin dye FW-1 and D-A-π-A featured dye WS-5, the different bond-breaking mode in TOF-SIMS and dynamic dye-loading amount during the coadsorption process are well compared with two different anchoring groups such as benzoic acid and cyanoacrylic acid...
April 20, 2017: ACS Applied Materials & Interfaces
Fangjun Luo, Lina Zheng, Yue Hu, Shuxian Liu, Yan Wang, Zhongkui Xiong, Xin Hu, Feng Tan
RNA-based vaccine represents an irresistible and safe immunization strategy with decreasing theoretical risks of genomic integration and malignant cell transformation. To our knowledge, however, there is no report about development of RNA vaccine against Toxoplasma gondii infection. We have previously demonstrated that the recombinant T. gondii nucleoside triphosphate hydrolase-II (NTPase-II) protein is able to provide protective Th1 cell-mediated immunity against T. gondii. Herein, we evaluated the immunogenic potential of a self-amplifying RNA vaccine-encoding T...
2017: Frontiers in Microbiology
Ovidio Peña-Rodríguez, Alejandro Prada, José Olivares, Alicia Oliver, Luis Rodríguez-Fernández, Héctor G Silva-Pereyra, Eduardo Bringa, José Manuel Perlado, Antonio Rivera
In this work we have studied the elongation of silver nanoparticles irradiated with 40 MeV Bromine ions by means of in situ optical measurements, transmission electron microscopy and molecular dynamics simulations. The localized surface plasmon resonance of silver nanoparticles has a strong dependence on the particle shape and size, which allowed us to obtain the geometrical parameters with remarkable accuracy by means of a fit of the optical spectra. Optical results have been compared with transmission electron microscopy images and molecular dynamics simulations and the agreement is excellent in both cases...
April 19, 2017: Scientific Reports
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