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https://www.readbyqxmd.com/read/28724252/effect-of-operating-conditions-on-speciation-and-bioavailability-of-trace-metals-in-submerged-anaerobic-membrane-bioreactors
#1
Pham Minh Thanh, Balachandran Ketheesan, Yan Zhou, David C Stuckey
This study investigated the effect of changes in pH (7, 6.5 and 6), hydraulic retention time (HRT) (6h, 4h, and 2h), solids retention time (SRT) (100d and 25d) on the speciation of trace metals (TMs) in submerged anaerobic membrane bioreactors (SAMBRs). The results showed that the metal retention capacity of SAMBRs reduced when the pH, HRT and SRT were reduced i.e. up to 21.9%, 39.1%, and 17.1%, respectively, but it was also found that the speciation of these TMs generally shifted towards highly bioavailable fractions i...
July 8, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28724226/application-of-a-crustacean-bioassay-to-evaluate-a-multi-contaminated-metal-pah-pcb-harbor-sediment-before-and-after-electrokinetic-remediation-using-eco-friendly-enhancing-agents
#2
Y Tian, C Boulangé-Lecomte, A Benamar, N Giusti-Petrucciani, A Duflot, S Olivier, C Frederick, J Forget-Leray, F Portet-Koltalo
Electrokinetic (EK) remediation can be a suitable technology for treating contaminated dredged harbor sediment, stored on terrestrial disposal sites. Citric acid (CA) and biosurfactants (rhamnolipids and saponin) were chosen as enhancing agents for simultaneous metal (Cd, Cr, Cu, Pb, Zn) and PAH/PCB removal by EK because of their potential low toxicity with a view to site restoration. Three EK runs were performed using a periodic voltage (1Vcm(-1)) and various concentrations of agents. The best combination of CA (0...
July 14, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28723955/crystal-structure-and-functional-characterization-of-an-isoaspartyl-dipeptidase-cpsiada-from-colwellia-psychrerythraea-strain-34h
#3
Sun-Ha Park, Chang Woo Lee, Sung Gu Lee, Seung Chul Shin, Hak Jun Kim, Hyun Park, Jun Hyuck Lee
Isoaspartyl dipeptidase (IadA) is an enzyme that catalyzes the hydrolysis of an isoaspartyl dipeptide-like moiety, which can be inappropriately formed in proteins, between the β-carboxyl group side chain of Asp and the amino group of the following amino acid. Here, we have determined the structures of an isoaspartyl dipeptidase (CpsIadA) from Colwellia psychrerythraea, both ligand-free and that complexed with β-isoaspartyl lysine, at 1.85-Å and 2.33-Å resolution, respectively. In both structures, CpsIadA formed an octamer with two Zn ions in the active site...
2017: PloS One
https://www.readbyqxmd.com/read/28723895/visible-light-driven-methane-formation-from-co2-with-a-molecular-iron-catalyst
#4
Heng Rao, Luciana C Schmidt, Julien Bonin, Marc Robert
Converting CO2 into fuel or chemical feedstock compounds could in principle reduce fossil fuel consumption and climate-changing CO2 emissions. One strategy aims for electrochemical conversions powered by electricity from renewable sources, but photochemical approaches driven by sunlight are also conceivable. A considerable challenge in both approaches is the development of efficient and selective catalysts, ideally based on cheap and Earth-abundant elements rather than expensive precious metals. Of the molecular photo- and electrocatalysts reported, only a few catalysts are stable and selective for CO2 reduction; moreover, these catalysts produce primarily CO or HCOOH, and catalysts capable of generating even low to moderate yields of highly reduced hydrocarbons remain rare...
July 17, 2017: Nature
https://www.readbyqxmd.com/read/28723208/the-triple-roles-of-glutathione-for-a-dna-cleaving-dnazyme-and-development-of-a-fluorescent-glutathione-cu-2-dependent-dnazyme-sensor-for-detection-of-cu-2-in-drinking-water
#5
Shijin Wang, Chengcheng Liu, Guiying Li, Yongjie Sheng, Yanhong Sun, Hongyue Rui, Jin Zhang, Jiacui Xu, Dazhi Jiang
Pistol-like DNAzyme (PLDz) is an oxidative DNA-cleaving catalytic DNA with ascorbic acid as cofactor. Herein, glutathione was induced into the reaction system to maintain reduced ascorbic acid levels for higher efficient cleavage. However, data indicated that glutathione played triple roles in PLDz-catalyzed reactions. Glutathione alone had no effect on PLDz, and showed inhibitory effect on ascorbic acid-induced PLDz catalysis, but exhibited stimulating effect on Cu(2+)-promoted self-cleavage of PLDz. Further analysis of the effect of glutathione/Cu(2+) on PLDz indicated that H2O2 played a key role in PLDz catalysis...
March 24, 2017: ACS Sensors
https://www.readbyqxmd.com/read/28723203/multicolor-functional-carbon-dots-via-one-step-refluxing-synthesis
#6
Ting-Yi Wang, Chong-You Chen, Chang-Ming Wang, Ying Zi Tan, Wei-Ssu Liao
Carbon dots are admirable fluorescent nanomaterials due to their low cost, high photostability, excellent biocompatibility, and environmental friendliness. Most conventional carbon dot fabrication approaches produce single-colored fluorescent material in the preparation process; different methods are therefore required to synthesize distinct carbon dots for specific optical applications. In this study, carbon dots carrying different emission colors are prepared through a one-step refluxing process. The emission of these materials can be well-tuned by sodium hydroxide content in the precursor solution...
March 24, 2017: ACS Sensors
https://www.readbyqxmd.com/read/28723189/ionophore-based-titrimetric-detection-of-alkali-metal-ions-in-serum
#7
Jingying Zhai, Xiaojiang Xie, Thomas Cherubini, Eric Bakker
While the titrimetric assay is one of the most precise analytical techniques available, only a limited list of complexometric chelators is available, as many otherwise promising reagents are not water-soluble. Recent work demonstrated successful titrimetry with ion-exchanging polymeric nanospheres containing hydrophobic complexing agents, so-called ionophores, opening an exciting avenue in this field. However, this method was limited to ionophores of very high affinity to the analyte and exhibited a relatively limited titration capacity...
April 28, 2017: ACS Sensors
https://www.readbyqxmd.com/read/28723165/kinetic-discrimination-of-metal-ions-using-dna-for-highly-sensitive-and-selective-cr-3-detection
#8
Wang Li, Zijie Zhang, Wenhu Zhou, Juewen Liu
Most metal sensors are designed for a strong binding affinity toward target metal ions, and the underlying principle relies on binding thermodynamics. The kinetic aspect of binding, however, was rarely explored for sensing. In this work, the binding kinetics of 19 common or toxic metal ions are compared based on a fluorescence quenching assay using DNA oligonucleotides as ligands. Among these metals, Cr(3+) shows uniquely slow fluorescence quenching kinetics, and the quenched fluorescence cannot be recovered by EDTA or sulfide...
May 26, 2017: ACS Sensors
https://www.readbyqxmd.com/read/28723143/an-ultrasensitive-plasmonic-nanosensor-for-aldehydes
#9
Meng Li, Lei Shi, Tao Xie, Chao Jing, Guangli Xiu, Yi-Tao Long
Glucose is the most common but important aldehyde, and it is necessary to create biosensors with high sensitivity and anti-interference to detect it. Under the existence of silver ions and aldehyde compounds, single gold nanoparticles and freshly formed silver atoms could respectively act as core and shell, which finally form a core-shell structure. By observing the reaction between glucose and Tollens' reagent, metallic silver was found to be reduced on the surface of gold nanoparticles and formed Au@Ag nanoparticles that lead to a direct wavelength shift...
February 24, 2017: ACS Sensors
https://www.readbyqxmd.com/read/28723118/valence-states-modulation-strategy-for-picomole-level-assay-of-hg-2-in-drinking-and-environmental-water-by-directional-self-assembly-of-gold-nanorods
#10
Lu Chen, Linlin Lu, Sufan Wang, Yunsheng Xia
In this study, we present a valence states modulation strategy for picomole level assay of Hg(2+) using directional self-assembly of gold nanorods (AuNRs) as signal readout. Hg(2+) ions are first controllably reduced to Hg(+) ions by appropriate ascorbic acid, and the reduced Hg(+) ions react with the tips of the preadded AuNRs and form gold amalgam. Such Hg(+) decorated AuNRs then end-to-end self-assemble into one-dimensional architectures by the bridging effects of lysine based on the high affinity of NH2-Hg(+) interactions...
June 23, 2017: ACS Sensors
https://www.readbyqxmd.com/read/28723109/fast-surface-acoustic-wave-based-sensors-to-investigate-the-kinetics-of-gas-uptake-in-ultra-microporous-frameworks
#11
Benjamin Paschke, Achim Wixforth, Dmytro Denysenko, Dirk Volkmer
Observation of the kinetics and measurement of the activation energies for gas diffusion in porous materials requires very fast and sensitive sensors. In this work, thin films of metal-organic frameworks (MOFs) with different pore sizes are grown on a surface acoustic wave (SAW) substrate, resulting in very sensitive and specific sensor systems for the detection of various gases at very short time scales. Using specially designed SAW delay lines for the detection, up to 200-nm-wide cubic MOF crystals were grown directly from a solution on the sensitive sensor chip area...
June 23, 2017: ACS Sensors
https://www.readbyqxmd.com/read/28723097/decorating-of-ag-and-cuo-on-cu-nanoparticles-for-the-enhanced-high-catalytic-activity-to-the-degradation-of-organic-pollutants
#12
Yu Liang, Zhe Chen, Wen Yao, Pengyi Wang, Shujun Yu, Xiangke Wang
The metal/semiconductor composites are promising catalysts with superior catalytic activity. In this work, a Cu/CuO-Ag composite with structure that Ag and CuO nanoparticles (NPs) decorated on the surface of Cu were fabricated via a facile in-situ method. With the characterization by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDX) and inductively coupled plasma atomic emission spectrometry (ICP-AES), the structure and structure and component of Cu/CuO-Ag composite were well-defined...
July 19, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28723096/nickel-particles-selectively-confined-in-the-mesoporous-channels-of-sba-15-yielding-a-very-stable-catalyst-for-drm-reaction
#13
Alberto Rodriguez-Gomez, Rosa Pereñiguez, Alfonso Caballero
A series of four Ni catalysts supported on SBA-15 and on a high surface area SiO2 have been prepared by modified impregnation (ImU) and deposition-precipitation (DP) methods. The catalysts have been extensively characterized, including in situ XAS and XPS techniques, and their catalytic activities evaluated in the dry reforming reaction of methane (DRM). The combined use of a surface sensitive technique (XPS) with a bulk sensitive one (XAS) has allowed to determine the location of nickel particles on each catalyst after reduction at high temperature (750 oC)...
July 19, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28723093/plasmonic-aerogels-as-a-3d-nanoscale-platform-for-solar-fuels-photocatalysis
#14
Paul A DeSario, Jeremy J Pietron, Adam Dunkelberger, Todd H Brintlinger, Olga Baturina, Rhonda M Stroud, Jeffrey C Owrutsky, Debra R Rolison
We use plasmonic Au-TiO2 aerogels as a platform in which to marry synthetically thickened particle-particle junctions in TiO2 aerogel networks and Au||TiO2 interfaces and then investigate their cooperative influence on photocatalytic hydrogen (H2) generation under both broadband (i.e., UV + visible light) and visible-only excitation. In doing so, we elucidate the dual functions that incorporated Au can play as a water reduction/H2 generation co-catalyst and as a plasmonic sensitizer. We also introduce non-plasmonic Pt co-catalyst nanoparticles into our composite aerogels in order to leverage the catalytic water-reducing abilities of Pt...
July 19, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28723082/mixed-valency-in-a-3d-semiconducting-iron-fluoranilate-coordination-polymer
#15
Ryuichi Murase, Brendan F Abrahams, Deanna M D'Alessandro, Casey G Davies, Timothy A Hudson, Guy N L Jameson, Boujemaa Moubaraki, Keith S Murray, Richard Robson, Ashley L Sutton
A pair of coordination polymers of composition (NBu4)2[M2(fan)3] (fan = fluoranilate; M = Fe and Zn) were synthesized and structurally characterized. In each case the compound consists of a pair of interpenetrating three-dimensional, (10,3)-a networks in which metal centers are linked by chelating/bridging fluoranilate ligands. Tetrabutylammonium cations are located in the spaces between the two networks. Despite the structural similarity, significant differences exist between (NBu4)2[Fe2(fan)3] and (NBu4)2[Zn2(fan)3] with respect to the oxidation states of the metal centers and ligands...
July 19, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28723073/experimental-determination-of-the-ionization-energies-of-mose2-ws2-and-mos2-on-sio2-using-photoemission-electron-microscopy
#16
Kunttal Keyshar, Morgann Berg, Xiang Zhang, Robert Vajtai, Gautam Gupta, Calvin K Chan, Thomas E Beechem, Pulickel M Ajayan, Aditya D Mohite, Taisuke Ohta
The values of the ionization energies of transition metal dichalcogenides (TMDs) are needed to assess their potential usefulness in semiconductor heterojunctions for high-performance optoelectronics. Here, we report on the systematic determination of ionization energies for three prototypical TMD monolayers (MoSe2, WS2, and MoS2) on SiO2 using photoemission electron microscopy with deep ultraviolet illumination. The ionization energy displays a progressive decrease from MoS2, to WS2, to MoSe2, in agreement with predictions of density functional theory calculations...
July 19, 2017: ACS Nano
https://www.readbyqxmd.com/read/28722816/construction-of-all-solid-state-batteries-based-on-sulfur-graphene-composite-and-li9-54si1-74p1-44s11-7cl0-3-solid-electrolyte
#17
Ruochen Xu, Zhang Wu, Shenzhao Zhang, Xiuli Wang, Yan Xia, Xinhui Xia, Xiaohua Huang, Jiangping Tu
Herein we report an effective way for construction of all-solid-state lithium-sulfur batteries (LSBs) with sulfur/reduced graphene oxide (rGO) and Li9.54Si1.74P1.44S11.7Cl0.3 solid electrolyte. In the composite cathode, the Li9.54Si1.74P1.44S11.7Cl0.3 powder is homogeneously mixed with the S/rGO composite to enhance the ionic conductivity. Coupled with metallic Li anode and solid electrolyte, the designed S/rGO-Li9.54Si1.74P1.44S11.7Cl0.3 composite cathode exhibits a high specific capacity and good cyclic stability...
July 19, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28722797/highly-selective-enrichment-of-phosphopeptides-by-on-chip-indium-oxide-functionalized-magnetic-nanoparticles-coupled-with-maldi-tof-ms
#18
Dandan Jiang, Naizhong Song, Xiqian Li, Jiutong Ma, Qiong Jia
Selective and efficient preconcentration is indispensable for low concentration of phosphopeptides in phosphorylated protein-related samples prior to MS-based analysis. Herein, an on-chip system coupled magnetic SPE with MALDI-TOF MS was designed. A metal oxide affinity chromatography (MOAC) material, indium oxide, was coated on the surface of Fe3 O4 magnetic nanoparticles (MNPs) to prepare the adsorbent, spatially confined with an applied magnetic field. The adsorbent exhibited high selectivity for phosphopeptides in tryptic digests of the mixture of β-casein and BSA (1:1000) and the mixture of β-casein, BSA, and ovalbumin (1:100:100)...
July 19, 2017: Proteomics
https://www.readbyqxmd.com/read/28722444/topographically-flat-nanoplasmonic-sensor-chips-for-biosensing-and-materials-science
#19
Ferry Anggoro Ardy Nugroho, Rickard Frost, Tomasz J Antosiewicz, Joachim Fritzsche, Elin M Larsson Langhammer, Christoph Langhammer
Nanoplasmonic sensors typically comprise arrangements of noble metal nanoparticles on a dielectric support. Thus, they are intrinsically characterized by surface topography with corrugations at the 10-100 nm length scale. While irrelevant in some bio- and chemosensing applications, it is also to be expected that the surface topography significantly influences the interaction between solids, fluids, nanoparticles and (bio)molecules, and the nanoplasmonic sensor surface. To address this issue, we present a wafer-scale nanolithography-based fabrication approach for high-temperature compatible, chemically inert, topographically flat, and laterally homogeneous nanoplasmonic sensor chips...
January 27, 2017: ACS Sensors
https://www.readbyqxmd.com/read/28722410/the-general-effect-of-van-der-waals-interactions-on-the-stability-of-alkoxy-intermediates-on-metal-surfaces
#20
Yun-Fei Xu, Wei Chen, Efthimios Kaxiras, Cynthia M Friend, Robert J Madix
The critical role of non-covalent van der Waals (vdW) interactions in determining the relative stability of alkoxy intermediates has been demonstrated for the Cu(110) surface using a combination of experiment and theory. The results may be significant for the selectivity control of copper-based reactions of alcohols. Previous examination of this effect on Au(110) was also extended to include higher molecular weight alcohols; on Cu(110) and Au(110) the hierarchy for the strength of binding of the alkoxys was found to be the same within experimental accuracy, with alkoxy species of greater chain length being more stable...
July 19, 2017: Journal of Physical Chemistry. B
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