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https://www.readbyqxmd.com/read/29776010/enhanced-furfural-yields-from-xylose-dehydration-in-the-gamma-valerolactone-water-solvent-system-at-elevated-temperatures
#1
Canan Sener, Ali Hussain Motagamwala, David Martin Alonso, James Dumesic
High yields of furfural (>90%) were achieved from xylose dehydration in a sustainable solvent system composed of -valerolactone (GVL), a biomass derived solvent, and water. It is identified that high reaction temperatures (e.g., 498 K) are required to achieve high furfural yield. Additionally, it is shown that the furfural yield at these temperatures is independent of the initial xylose concentration, and high furfural yield is obtained for industrially relevant xylose concentrations (10 wt%). A reaction kinetics model is developed to describe the experimental data obtained with solvent system composed of 80 wt% GVL and 20 wt% water across the range of reaction conditions studied (473 - 523 K, 1-10 mM acid catalyst, 66 - 660 mM xylose concentration)...
May 18, 2018: ChemSusChem
https://www.readbyqxmd.com/read/29775939/biodegradation-in-seawater-of-pah-and-alkylphenols-from-produced-water-of-a-north-sea-platform
#2
Synnøve Lofthus, Inger K Almås, Peter Evans, Oliver Pelz, Odd Gunnar Brakstad
Operational planned discharges of produced water (PW) to the marine environment from offshore oil production installations, contain low concentrations of dispersed oil compounds, like polycyclic aromatic hydrocarbons (PAHs) and alkylated phenols (APs). Biotransformation in natural seawater (SW) of naphthalenes/PAHs and phenol/APs in field-collected PW from a North Sea platform was investigated in this biodegradation study. The PW was diluted in SW from a Norwegian fjord, and the biodegradation study was performed in slowly rotating carousels at 13 °C over a period of 62 days...
May 4, 2018: Chemosphere
https://www.readbyqxmd.com/read/29775934/arsenic-speciation-dynamics-in-paddy-rice-soil-water-environment-sources-physico-chemical-and-biological-factors-a-review
#3
REVIEW
Prasanna Kumarathilaka, Saman Seneweera, Andrew Meharg, Jochen Bundschuh
Rice is the main staple carbohydrate source for billions of people worldwide. Natural geogenic and anthropogenic sources has led to high arsenic (As) concentrations in rice grains. This is because As is highly bioavailable to rice roots under conditions in which rice is cultivated. A multifaceted and interdisciplinary understanding, both of short-term and long-term effects, are required to identify spatial and temporal changes in As contamination levels in paddy soil-water systems. During flooding, soil pore waters are elevated in inorganic As compared to dryland cultivation systems, as anaerobism results in poorly mobile As(V), being reduced to highly mobile As(III)...
April 21, 2018: Water Research
https://www.readbyqxmd.com/read/29775910/hip-and-patellofemoral-joint-loading-during-gait-are-increased-in-children-with-idiopathic-torsional-deformities
#4
Elyse Passmore, H Kerr Graham, Marcus G Pandy, Morgan Sangeux
BACKGROUND: Torsional deformities of the femur and tibia are associated with gait impairments and joint pain. Several studies have investigated these gait deviations in children with cerebral palsy. However, relatively little is known about gait deviations in children with idiopathic torsion and debate ensues about the management of these patients. RESEARCH QUESTION: What are the effects of idiopathic increased femoral neck anteversion and external tibial torsion on lower-limb kinematics, kinetics and joint loading during gait in children and adolescents...
May 9, 2018: Gait & Posture
https://www.readbyqxmd.com/read/29775905/kinetic-modelling-of-methane-production-during-bio-electrolysis-from-anaerobic-co-digestion-of-sewage-sludge-and-food-waste
#5
Kalp Bhusan Prajapati, Rajesh Singh
In present study batch tests were performed to investigate the enhancement in methane production under bio-electrolysis anaerobic co-digestion of sewage sludge and food waste. The bio-electrolysis reactor system (B-EL) yield more methane 148.5 ml/g COD in comparison to reactor system without bio-electrolysis (B-CONT) 125.1 ml/g COD. Whereas bio-electrolysis reactor system (C-EL) Iron Scraps amended yield lesser methane (51.2 ml/g COD) in comparison to control bio-electrolysis reactor system without Iron scraps (C-CONT - 114...
May 10, 2018: Bioresource Technology
https://www.readbyqxmd.com/read/29775880/photocatalytic-reductive-dechlorination-of-2-chlorodibenzo-p-dioxin-by-pd-modified-g-c-3-n-4-photocatalysts-under-uv-vis-irradiation-efficacy-kinetics-and-mechanism
#6
Jiafeng Ding, Gaoyuan Long, Yang Luo, Runze Sun, Mengxia Chen, Yajun Li, Yanfang Zhou, Xinhua Xu, Weirong Zhao
Polychlorinated dibenzo-p-dioxins (PCDDs), as a group of notorious anthropogenic environmental toxicants, are arguably ubiquitous in nature. In this study, we investigated the photocatalytic reductive dechlorination of 2-chlorodibenzo-p-dioxin (2-CDD) over Pd/g-C3 N4 catalysts under UV-vis irradiation. The g-C3 N4 and a series of Pd/g-C3 N4 catalysts were prepared by thermal polymerization and mechanical mixing-illumination method and characterized by XRD, TEM, BET, SEM and UV-vis DRS analyses. Among all the samples, the Pd/g-C3 N4 (5 wt%) yielded the optimal dechlorination activity with a total 2-CDD conversion of 54% within 4 h, and 76% of those converted 2-CDD were evolved to dibenzo-p-dioxin (DD)...
May 9, 2018: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/29775856/a-simple-ultrasensitive-electrochemical-sensor-for-simultaneous-determination-of-gallic-acid-and-uric-acid-in-human-urine-and-fruit-juices-based-on-zirconia-choline-chloride-gold-nanoparticles-modified-carbon-paste-electrode
#7
Seyed Alireza Shahamirifard, Mehrorang Ghaedi, Zahra Razmi, Shaaker Hajati
The determination of gallic acid (GA) and uric acid (UA) is essential due to their biological properties. Numerous methods have been reported for the analysis of GA and UA in various real samples. However, the development of a simple, rapid and practical sensor still remains a great challenge. Here, a carbon paste electrode (CPE) was modified by nanocomposite containing zirconia nanoparticles (ZrO2 NPs), Choline chloride (ChCl) and gold nanoparticles (AuNPs) to construct ZrO2 -ChCl-AuNPs/CPE as electrochemical sensor for the simultaneous electro-oxidation of GA and UA...
May 8, 2018: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/29775829/synthesis-of-mesoporous-triple-metal-nanosorbent-from-layered-double-hydroxide-as-an-efficient-new-sorbent-for-removal-of-dye-from-water-and-wastewater
#8
Miloš Kostić, Miljana Radović, Nena Velinov, Slobodan Najdanović, Danijela Bojić, Andrew Hurt, Aleksandar Bojić
In this study, co-precipitation synthesis of the mesoporous triple-metal nanosorbent from Fe, Cu, Ni layered double hydroxide (FeCuNi-LDH), on the basis of the data obtained from the TG analysis was carried out. The FTIR spectroscopy and XRD results confirm the formation of CuO, NiO and Fe2 O3 nanoparticles, while the EDX analysis does not show significant variations on the surface in elemental composition. BET analysis shows that FeCuNi-280 (FeCuNi-LDH calcinated at 280 °C) with mesoporous structure, has larger surface area compared to FeCuNi-LDH and FeCuNi-550 (FeCuNi-LDH calcinated at 550 °C)...
May 15, 2018: Ecotoxicology and Environmental Safety
https://www.readbyqxmd.com/read/29775731/targeted-and-controlled-drug-delivery-by-multifunctional-mesoporous-silica-nanoparticles-with-internal-fluorescent-conjugates-and-external-polydopamine-and-graphene-oxide-layers
#9
Anh-Vy Tran, KyuHwan Shim, Thu-Thao Vo Thi, Jeong-Keun Kook, Seong Soo A An, Sang-Wha Lee
This study demonstrated the targeted delivery and controlled release of cisplatin drug molecules from doubly decorated mesoporous silica nanoparticles (MSNs), which were internally grafted with fluorescent conjugates and externally coated with polydopamine (PDA) and graphene oxide (GO) layers. The brush-like internal conjugates conferred fluorescent functionality and high capacity of cisplatin loading into MSNs, as well as contributing to a sustained release of the cisplatin through a porous channel with the assistance of external PDA layer...
May 15, 2018: Acta Biomaterialia
https://www.readbyqxmd.com/read/29775683/viscoelastic-modeling-of-the-fusion-of-multicellular-tumor-spheroids-in-growth-phase
#10
Guillaume Dechristé, Jérôme Fehrenbach, Elena Griseti, Valérie Lobjois, Clair Poignard
BACKGROUND: Since several decades, the experiments have highlighted the analogy of fusing cell aggregates with liquid droplets. The physical macroscopic models have been derived under incompressible assumptions. The aim of this paper is to provide a 3D model of growing spheroids, which is more relevant regarding embryo cell aggregates or tumor cell spheroids. METHODS: We extend the past approach to a compressible 3D framework in order to account for the tumor spheroid growth...
May 15, 2018: Journal of Theoretical Biology
https://www.readbyqxmd.com/read/29775583/correlating-transcription-initiation-and-conformational-changes-by-a-single-subunit-rna-polymerase-with-near-base-pair-resolution
#11
Hye Ran Koh, Rahul Roy, Maria Sorokina, Guo-Qing Tang, Divya Nandakumar, Smita S Patel, Taekjip Ha
We provide a comprehensive analysis of transcription in real time by T7 RNA Polymerase (RNAP) using single-molecule fluorescence resonance energy transfer by monitoring the entire life history of transcription initiation, including stepwise RNA synthesis with near base-pair resolution, abortive cycling, and transition into elongation. Kinetically branching pathways were observed for abortive initiation with an RNAP either recycling on the same promoter or exchanging with another RNAP from solution. We detected fast and slow populations of RNAP in their transition into elongation, consistent with the efficient and delayed promoter release, respectively, observed in ensemble studies...
May 17, 2018: Molecular Cell
https://www.readbyqxmd.com/read/29775503/artificial-rod-and-cone-photoreceptors-with-human-like-spectral-sensitivities
#12
Byeongho Park, Heehong Yang, Tai Hwan Ha, Hyun Seo Park, Seung Ja Oh, Yong-Sang Ryu, Youngho Cho, Hyo-Suk Kim, Juyeong Oh, Dong Kyu Lee, Chulki Kim, Taikjin Lee, Minah Seo, Jaebin Choi, Young Min Jhon, Deok Ha Woo, Seok Lee, Seok Hwan Kim, Hyuk-Jae Lee, Seong Chan Jun, Hyun Seok Song, Tai Hyun Park, Jae Hun Kim
Photosensitive materials contain biologically engineered elements and are constructed using delicate techniques, with special attention devoted to efficiency, stability, and biocompatibility. However, to date, no photosensitive material has been developed to replace damaged visual-systems to detect light and transmit the signal to a neuron in the human body. In the current study, artificial nanovesicle-based photosensitive materials are observed to possess the characteristics of photoreceptors similar to the human eye...
May 18, 2018: Advanced Materials
https://www.readbyqxmd.com/read/29775455/atomic-resolution-mechanism-of-ligand-binding-to-a-solvent-inaccessible-cavity-in-t4-lysozyme
#13
Jagannath Mondal, Navjeet Ahalawat, Subhendu Pandit, Lewis E Kay, Pramodh Vallurupalli
Ligand binding sites in proteins are often localized to deeply buried cavities, inaccessible to bulk solvent. Yet, in many cases binding of cognate ligands occurs rapidly. An intriguing system is presented by the L99A cavity mutant of T4 Lysozyme (T4L L99A) that rapidly binds benzene (~106 M-1s-1). Although the protein has long served as a model system for protein thermodynamics and crystal structures of both free and benzene-bound T4L L99A are available, the kinetic pathways by which benzene reaches its solvent-inaccessible binding cavity remain elusive...
May 18, 2018: PLoS Computational Biology
https://www.readbyqxmd.com/read/29775407/effect-of-healthy-aging-and-sex-on-middle-cerebral-artery-blood-velocity-dynamics-during-moderate-intensity-exercise
#14
Jaimie L Ward, Jesse C Craig, Yumei Liu, Eric Dennis Vidoni, Rebecca Malesky, David C Poole, Sandra A Billinger
Cerebral blood flow (CBF) velocity measured in the middle cerebral artery (MCAV ) increases with finite kinetics during moderate intensity exercise and both the amplitude and dynamics of the response provide invaluable insights into the controlling mechanisms. The MCAV response following exercise onset is well fit to an exponential model in young individuals but remains to be characterized in their older counterparts. The responsiveness of vasomotor control degrades with advancing age, especially in skeletal muscle, and we tested the hypothesis that older subjects would evince a slower and reduced MCAV response to exercise...
May 18, 2018: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29775377/rate-and-state-friction-relation-for-nanoscale-contacts-thermally-activated-prandtl-tomlinson-model-with-chemical-aging
#15
Kaiwen Tian, David L Goldsby, Robert W Carpick
Rate and state friction (RSF) laws are widely used empirical relationships that describe macroscale to microscale frictional behavior. They entail a linear combination of the direct effect (the increase of friction with sliding velocity due to the reduced influence of thermal excitations) and the evolution effect (the change in friction with changes in contact "state," such as the real contact area or the degree of interfacial chemical bonds). Recent atomic force microscope (AFM) experiments and simulations found that nanoscale single-asperity amorphous silica-silica contacts exhibit logarithmic aging (increasing friction with time) over several decades of contact time, due to the formation of interfacial chemical bonds...
May 4, 2018: Physical Review Letters
https://www.readbyqxmd.com/read/29775363/charge-transfer-processes-in-warm-dense-matter-selective-spectral-filtering-for-laser-accelerated-ion-beams
#16
J Braenzel, M D Barriga-Carrasco, R Morales, M Schnürer
We investigate, both experimentally and theoretically, how the spectral distribution of laser accelerated carbon ions can be filtered by charge exchange processes in a double foil target setup. Carbon ions at multiple charge states with an initially wide kinetic energy spectrum, from 0.1 to 18 MeV, were detected with a remarkably narrow spectral bandwidth after they had passed through an ultrathin and partially ionized foil. With our theoretical calculations, we demonstrate that this process is a consequence of the evolution of the carbon ion charge states in the second foil...
May 4, 2018: Physical Review Letters
https://www.readbyqxmd.com/read/29775355/weakly-nonergodic-dynamics-in-the-gross-pitaevskii-lattice
#17
Thudiyangal Mithun, Yagmur Kati, Carlo Danieli, Sergej Flach
The microcanonical Gross-Pitaevskii (also known as the semiclassical Bose-Hubbard) lattice model dynamics is characterized by a pair of energy and norm densities. The grand canonical Gibbs distribution fails to describe a part of the density space, due to the boundedness of its kinetic energy spectrum. We define Poincaré equilibrium manifolds and compute the statistics of microcanonical excursion times off them. The tails of the distribution functions quantify the proximity of the many-body dynamics to a weakly nonergodic phase, which occurs when the average excursion time is infinite...
May 4, 2018: Physical Review Letters
https://www.readbyqxmd.com/read/29775327/rydberg-dressed-magneto-optical-trap
#18
A D Bounds, N C Jackson, R K Hanley, R Faoro, E M Bridge, P Huillery, M P A Jones
We propose and demonstrate the laser cooling and trapping of Rydberg-dressed Sr atoms. By off-resonantly coupling the excited state of a narrow (7 kHz) cooling transition to a high-lying Rydberg state, we transfer Rydberg properties such as enhanced electric polarizability to a stable magneto-optical trap operating at <1  μK. Simulations show that it is possible to reach a regime where the long-range interaction between Rydberg-dressed atoms becomes comparable to the kinetic energy, opening a route to combining laser cooling with tunable long-range interactions...
May 4, 2018: Physical Review Letters
https://www.readbyqxmd.com/read/29775321/direct-ortho-c-h-aminoalkylation-of-2-substituted-pyridine-derivatives-catalyzed-by-yttrium-complexes-with-n-n-diarylethylenediamido-ligands
#19
Abhinanda Kundu, Mariko Inoue, Haruki Nagae, Hayato Tsurugi, Kazushi Mashima
A mixed ligated amidoyttrium complex, Y(NBn2 )(L1)(THF)2 (8, L1 = N,N'-bis(2,6-diisopropylphenyl)ethylenediamine), served as a catalyst for addition of the ortho-pyridyl C(sp2 )-H bond of 2-substituted pyridines to non-activated imines; complex 8 showed superior catalytic performance compared with Y[N(SiMe3 )2 ]3 (1) and Y[N(SiMe3 )2 ]2 (NBn2 )(THF) (2). Concerning the reaction mechanism, we conducted a stoichiometric reaction of an alkylyttrium complex, Y(CH2 SiMe3 )(L1)(THF)2 (7), with 2-ethylpyridine (4e), giving a mixture of (η3 -pyridylmethyl)yttrium complex 9 and (η2 -pyridyl)yttrium complex 10 along with elimination of SiMe4 ...
May 18, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29775306/mechanistic-study-on-water-splitting-reactions-by-small-silicon-clusters-si-3-x-x-si-be-mg-ca
#20
Tran Dieu Hang, Minh Tho Nguyen
(Abstract) Interaction, dissociation and dehydrogenation reactions of water monomer and dimer with pure and mixed tetrameric silicon clusters Si3X with X = Si, Be, Mg, Ca were investigated using high accuracy quantum chemical calculations. While geometries were optimized using the DFT/B3LYP functional with the aug-cc-pVTZ basis set, reaction energy profiles were constructed making use of the coupled-cluster theory with extrapolation to complete basis set, CCSD(T)/CBS. Cleavage of the O-H bond in water dimer is found to be more favored than that of water monomer in the reaction with Si4...
May 18, 2018: Journal of Physical Chemistry. A
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