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https://www.readbyqxmd.com/read/28231483/a-novel-redox-regulator-mntnbuoe-2-pyp-5-enhances-normal-hematopoietic-stem-progenitor-cell-function
#1
Y Zhao, D W Carroll, Y You, L Chaiswing, R Wen, I Batinic-Haberle, S Bondada, Y Liang, D K St Clair
The signaling of reactive oxygen species (ROS) is essential for the maintenance of normal cellular function. However, whether and how ROS regulate stem cells are unclear. Here, we demonstrate that, in transgenic mice expressing the human manganese superoxide dismutase (MnSOD) gene, a scavenger of ROS in mitochondria, the number and function of mouse hematopoietic stem/progenitor cells (HSPC) under physiological conditions are enhanced. Importantly, giving MnTnBuOE-2-PyP(5+)(MnP), a redox- active MnSOD mimetic, to mouse primary bone marrow cells or to C57B/L6 mice significantly enhances the number of HSPCs...
February 10, 2017: Redox Biology
https://www.readbyqxmd.com/read/28231430/combined-high-stretchability-and-gas-barrier-in-hydrogen-bonded-multilayer-nanobrick-wall-thin-films
#2
Shuang Qin, Yixuan Song, Michael Floto, Jaime C Grunlan
Hydrogen-bonded multilayer thin films are very stretchable, but their gas barrier properties are modest compared to more traditional ionically-bonded assemblies. In an effort to improve the gas barrier of poly(ethylene oxide) (PEO) - poly(acrylic acid) (PAA) multilayer films, without sacrificing stretchability, montmorillonite (MMT) clay platelets were combined with PAA and alternately deposited with PEO. A ten bilayer PEO/PAA+MMT film (432 nm thick), deposited on a 1 mm PU substrate, resulted in a 54X reduction in oxygen transmission rate after exposure to a 20% strain...
February 23, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28230998/influence-of-the-anomeric-conformation-in-the-intermolecular-interactions-of-glucose
#3
Imanol Usabiaga, Jorge González, Iker León, Pedro Felipe Arnaiz, Emilio J Cocinero, Jose A Fernandez
Carbohydrates are together with amino acids, DNA bases and lipids the building blocks of living beings. They play a central role in basic functions as immunity and signaling, which are governed by non-covalent interactions between sugar units and/or with other biomolecules. To get insights on such interactions between monosaccharide units, we used a combination of mass-resolved laser spectroscopy in supersonic expansions and molecular structure calculations. The results obtained clearly demonstrate that the small stability difference between the α/β anomers of glucopyranose derivatives is reversed and amplified during molecular aggregation, making the complexes of the β-anomers significantly more stable...
February 23, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28230971/multifaceted-gold-palladium-bimetallic-nanorods-and-their-geometric-compositional-and-catalytic-tunabilities
#4
Lichao Sun, Qingfeng Zhang, Guangfang Grace Li, Esteban Villarreal, Xiaoqi Fu, Hui Wang
Kinetically controlled, seed-mediated coreduction provides a robust and versatile synthetic approach to multimetallic nanoparticles with precisely controlled geometries and compositions. Here we demonstrate that single-crystalline cylindrical Au nanorods selectively transform into a series of structurally distinct Au@Au-Pd alloy core-shell bimetallic nanorods with exotic multifaceted geometries enclosed by specific types of facets upon seed-mediated Au-Pd coreduction under diffusion controlled conditions. By adjusting several key synthetic parameters, such as the Pd/Au precursor ratio, the reducing agent concentration, the capping surfactant concentration, and foreign metal ion additives, we have been able to simultaneously fine-tailor the atomic-level surface structures and fine-tune the compositional stoichiometries of the multifaceted Au-Pd bimetallic nanorods...
February 23, 2017: ACS Nano
https://www.readbyqxmd.com/read/28230880/atomic-layer-deposited-ultrafine-mos2-nanocrystals-on-cobalt-foam-for-efficient-and-stable-electrochemical-oxygen-evolution
#5
Dehua Xiong, Qingqing Zhang, Wei Li, Junjie Li, Xiuli Fu, M F Cerqueira, Pedro Alpuim, Lifeng Liu
Ultrafine molybdenum sulfide (MoS2) nanocrystals are grown on a porous cobalt (Co) foam current collector by atomic layer deposition (ALD) using molybdenum hexacarbonyl and hydrogen sulfide as precursors. When used to catalyze the oxygen evolution reaction (OER), the optimal Co@MoS2 electrode, even with a MoS2 loading as small as 0.06 mg cm(-2), exhibits a large cathodic shift of ca. 200 mV in the onset potential (the potential at which the current density is 5 mA cm(-2)), a low overpotential of only 270 mV to attain an anodic current density of 10 mA cm(-2), much smaller charge transfer resistance and substantially improved long-term stability at both low and high current densities, with respect to the bare Co foam electrode, showing substantial promise for use as an efficient, low-cost and durable anode in water electrolyzers...
February 23, 2017: Nanoscale
https://www.readbyqxmd.com/read/28230756/synthesis-and-structural-evaluation-of-organo-ruthenium-complexes-with-%C3%AE-diketonates
#6
Matija Uršič, Tanja Lipec, Anton Meden, Iztok Turel
Four novel ruthenium organometallic complexes: [(η⁶-p-cymene)Ru(4,4,4-trifluoro-1-(4-bromophenyl)-1,3-butanedione)Cl] (1), [(η⁶-p-cymene)Ru(4,4,4-trifluoro-1-(4-bromophenyl)-1,3-butanedione)pta]PF₆ (2), [(η⁶-p-cymene)Ru(4,4,4-trifluoro-1-(4-iodophenyl)-1,3-butanedione)Cl] (3) and [(η⁶-p-cymene)Ru(4,4,4-trifluoro-1-(4-iodophenyl)-1,3-butanedione)pta]PF₆ (4) were synthesized and characterized by elemental analysis, infrared (IR), UV-Vis, NMR and mass spectroscopy and single-crystal X-ray diffraction...
February 20, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28230729/catechol-groups-enable-reactive-oxygen-species-scavenging-mediated-suppression-of-pkd-nfkappab-il-8-signaling-pathway-by-chlorogenic-and-caffeic-acids-in-human-intestinal-cells
#7
Hee Soon Shin, Hideo Satsu, Min-Jung Bae, Mamoru Totsuka, Makoto Shimizu
Chlorogenic acid (CHA) and caffeic acid (CA) are phenolic compounds found in coffee, which inhibit oxidative stress-induced interleukin (IL)-8 production in intestinal epithelial cells, thereby suppressing serious cellular injury and inflammatory intestinal diseases. Therefore, we investigated the anti-inflammatory mechanism of CHA and CA, both of which inhibited hydrogen peroxide (H₂O₂)-induced IL-8 transcriptional activity. They also significantly suppressed nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) transcriptional activity, nuclear translocation of the p65 subunit, and phosphorylation of IκB kinase (IKK)...
February 20, 2017: Nutrients
https://www.readbyqxmd.com/read/28230371/asymmetric-catalytic-1-2-hydroperoxidation-of-isatin-derived-ketimine-with-hydrogen-peroxide-in-the-crowding-environment-of-pegs
#8
Wengang Guo, Yan Liu, Can Li
The first enantioselective catalytic 1,2-hydroperoxidation has been achieved in the presence of PEG-600 using an acid-base bifunctional chiral squaramide as the organocatalyst, affording a range of enantioenriched α-N-substituted hydroperoxides bearing an oxindole moiety with excellent stereoselectivities (up to 99% ee).
February 23, 2017: Organic Letters
https://www.readbyqxmd.com/read/28230348/nmr-structures-of-gcn4p-are-largely-conserved-when-ion-pairs-are-disrupted-at-acidic-ph-but-show-a-relaxation-of-the-coiled-coil-superhelix
#9
Anne R Kaplan, Megan R Brady, Mark W Maciejewski, Richard A Kammerer, Andrei T Alexandrescu
To understand the roles ion pairs play in stabilizing coiled coils we determined NMR structures of GCN4p at three pH values. At pH 6.6 all acidic residues are fully charged, at pH 4.4 they are half-charged, and at pH 1.5 they are protonated and uncharged. The α-helix monomer and coiled coil structures of GCN4p are largely conserved, except for a loosening of the coiled coil quaternary structure with decreasing pH. Differences going from neutral to acidic pH include (i) an unwinding of the coiled coil superhelix due to the loss of inter-chain ion pair contacts, (ii) a small increase in the separation of the monomers in the dimer, (iii) a loosening of knobs-into-holes packing motifs, and (iv) an increased separation between oppositely charged residues that participate in ion pairs at neutral pH...
February 23, 2017: Biochemistry
https://www.readbyqxmd.com/read/28230297/spectroscopic-observation-of-a-hydrogenated-co-dimer-intermediate-during-co-reduction-on-cu-100-electrodes
#10
Elena Pérez-Gallent, Marta C Figueiredo, Federico Calle-Vallejo, Marc T M Koper
Carbon dioxide and carbon monoxide can be electrochemically reduced to useful products such as ethylene and ethanol on copper electrocatalysts. The process is yet to be optimized and the exact mechanism and the corresponding reaction intermediates are under debate or unknown. In particular, it has been hypothesized that the C-C bond formation proceeds via CO dimerization and further hydrogenation. Although computational support for this hypothesis exists, direct experimental evidence has been elusive. In this work, we detect a hydrogenated dimer intermediate (OCCOH) using Fourier transform infrared spectroscopy at low overpotentials in LiOH solutions...
February 23, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28230223/observation-of-charge-transfer-cascades-in-%C3%AE-fe2o3-irox-photoanodes-by-operando-x-ray-absorption-spectroscopy
#11
Alessandro Minguzzi, Alberto Naldoni, Ottavio Lugaresi, Elisabetta Achilli, Francesco D'Acapito, Francesco Malara, Cristina Locatelli, Alberto Vertova, Sandra Rondinini, Paolo Ghigna
Electrochemical devices for energy conversion and storage are central for a sustainable economy. The performance of electrodes is driven by charge transfer across different layer materials and an understanding of the mechanistics is pivotal to gain improved efficiency. Here, we directly observe the transfer of photogenerated charge carriers in a photoanode made of hematite (α-Fe2O3) and a hydrous iridium oxide (IrOx) overlayer, which plays a key role in photoelectrochemical water oxidation. Through the use of operando X-ray absorption spectroscopy (XAS), we probe the change in occupancy of the Ir 5d levels during optical band gap excitation of α-Fe2O3...
February 22, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28230219/piezochromism-and-structural-and-electronic-properties-of-benz-a-anthracene-under-pressure
#12
Weizhao Cai, Rong Zhang, Yansun Yao, Shanti Deemyad
We report a combined experimental and theoretical study of the high pressure behavior of a herringbone-type hydrocarbon benz[a]anthracene (BaA) using fluorescence spectroscopy, X-ray diffraction, optical absorption, photoconductivity measurements, and first-principles density functional theory (DFT) calculations. The ambient-pressure molecular solid phase of BaA was found to be stable up to ∼15.0 GPa. Increasing the external pressure within this region would induce a reversible piezochromic colour change in the sample, from yellow-green to light brown...
February 22, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28230207/enhanced-fenton-like-degradation-of-trichloroethylene-by-hydrogen-peroxide-activated-with-nanoscale-zero-valent-iron-loaded-on-biochar
#13
Jingchun Yan, Linbo Qian, Weiguo Gao, Yun Chen, Da Ouyang, Mengfang Chen
Composite of nanoscale Zero Valent Iron (nZVI) loaded on Biochar (BC) was prepared and characterized as hydrogen peroxide (H2O2) activator for the degradation of trichloroethylene (TCE). nZVI is homogeneously loaded on lamellarly structured BC surfaces to form nZVI/BC with specific surface area (SBET) of 184.91 m(2) g(-1), which can efficiently activate H2O2 to achieve TCE degradation efficiency of 98.9% with TOC removal of 78.2% within 30 min under the conditions of 0.10 mmol L(-1) TCE, 1.13 g L(-1) nZVI/BC and 1...
February 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28230105/interface-confined-hydrogen-evolution-reaction-in-zero-valent-metal-nanoparticles-intercalated-molybdenum-disulfide
#14
Zhongxin Chen, Kai Leng, Xiaoxu Zhao, Souradip Malkhandi, Wei Tang, Bingbing Tian, Lei Dong, Lirong Zheng, Ming Lin, Boon Siang Yeo, Kian Ping Loh
Interface confined reactions, which can modulate the bonding of reactants with catalytic centres and influence the rate of the mass transport from bulk solution, have emerged as a viable strategy for achieving highly stable and selective catalysis. Here we demonstrate that 1T'-enriched lithiated molybdenum disulfide is a highly powerful reducing agent, which can be exploited for the in-situ reduction of metal ions within the inner planes of lithiated molybdenum disulfide to form a zero valent metal-intercalated molybdenum disulfide...
February 23, 2017: Nature Communications
https://www.readbyqxmd.com/read/28230100/product-selectivity-in-plasmonic-photocatalysis-for-carbon-dioxide-hydrogenation
#15
Xiao Zhang, Xueqian Li, Du Zhang, Neil Qiang Su, Weitao Yang, Henry O Everitt, Jie Liu
Photocatalysis has not found widespread industrial adoption, in spite of decades of active research, because the challenges associated with catalyst illumination and turnover outweigh the touted advantages of replacing heat with light. A demonstration that light can control product selectivity in complex chemical reactions could prove to be transformative. Here, we show how the recently demonstrated plasmonic behaviour of rhodium nanoparticles profoundly improves their already excellent catalytic properties by simultaneously reducing the activation energy and selectively producing a desired but kinetically unfavourable product for the important carbon dioxide hydrogenation reaction...
February 23, 2017: Nature Communications
https://www.readbyqxmd.com/read/28229914/quercetin-exerts-preventive-ameliorative-and-prophylactic-effects-on-cadmium-chloride-induced-oxidative-stress-in-the-uterus-and-ovaries-of-female-wistar-rats
#16
Victor Udo Nna, Umar Zayyanu Usman, Emmanuel Oleba Ofutet, Daniel Udofia Owu
This study examined the possible protective effect of quercetin(QE) on cadmium chloride (CdCl2) - induced reproductive toxicity in female rats. Cadmium accumulated in the uterus and ovaries of rats, decreased antioxidants [superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione (GSH)], and raised the concentrations of malondialdehyde (MDA) and hydrogen peroxide (H2O2) in the uterus and ovaries of rats. Serum concentrations of estradiol, progesterone, follicle stimulating hormone and luteinizing hormone decreased significantly after CdCl2 administration...
February 13, 2017: Food and Chemical Toxicology
https://www.readbyqxmd.com/read/28229626/the-role-of-hydrogen-sulfide-in-homocysteine-induced-cardiodynamic-effects-and-oxidative-stress-markers-in-the-isolated-rat-heart
#17
M Stojanovic, V Zivkovic, I Srejovic, V Jakovljevic, N Jeremic, D Djuric
This study aimed to assess the role of H2S in homocysteine-induced cardiodynamic effects in the isolated rat heart. The hearts were retrogradely perfused according to the Langendorff technique. The maximum and minimum rates of pressure in the left ventricle (dp/dt max, dp/dt min), systolic and diastolic left ventricular pressures (SLVP, DLVP), heart rate (HR), and coronary flow (CF) were measured. A spectrophotometrical method was used to measure the following oxidative stress markers: index of lipid peroxidation (thiobarbituric acid reactive substances, TBARS), nitrite level (NO2(-)), superoxide anion radicals (O2(•-)), and hydrogen peroxide (H2O2) concentrations...
December 2016: Physiol Int
https://www.readbyqxmd.com/read/28229596/rh-catalyzed-asymmetric-hydrogenation-of-%C3%AE-substituted-vinyl-sulfones-an-efficient-approach-to-chiral-sulfones
#18
Liyang Shi, Biao Wei, Xuguang Yin, Peng Xue, Hui Lv, Xumu Zhang
Rh/(S)-(+)-DTBM-Segphos complex catalyzed asymmetric hydrogenation of α-substituted vinyl sulfones has been achieved, furnishing the desired products in high yields and excellent enantioselectivities (>90% yield, up to 99% ee). This method provided an efficient approach to α-substituted chiral sulfones under mild conditions and has potential applications in organic synthesis.
February 23, 2017: Organic Letters
https://www.readbyqxmd.com/read/28229532/n-butylidenephthalide-treatment-prolongs-life-span-and-attenuates-motor-neuron-loss-in-sod1-g93a-mouse-model-of-amyotrophic-lateral-sclerosis
#19
Qin-Ming Zhou, Jing-Jing Zhang, Song Li, Sheng Chen, Wei-Dong Le
AIMS: To evaluate the therapeutic effects of n-butylidenephthalide (BP) in SOD1(G93A) mouse model of amyotrophic lateral sclerosis and explore the possible mechanisms. METHODS: The SOD1(G93A) mice were treated by oral administration of BP (q.d., 400 mg/kg d) starting from 60 days of age and continuing until death. The rotarod test was performed to assess the disease onset. The expression levels of apoptosis-related proteins, inflammatory molecules, and autophagy-associated proteins were determined...
February 22, 2017: CNS Neuroscience & Therapeutics
https://www.readbyqxmd.com/read/28229519/reduced-sno2-porous-nanowires-with-a-high-density-of-grain-boundaries-as-catalysts-for-efficient-electrochemical-co2-into-hcooh-conversion
#20
Bijandra Kumar, Veerendra Atla, J Patrick Brian, Sudesh Kumari, Tu Quang Nguyen, Mahendra Sunkara, Joshua M Spurgeon
Electrochemical conversion of CO2 into energy-dense liquids, such as formic acid, is desirable as a hydrogen carrier and a chemical feedstock. SnOx is one of the few catalysts that reduce CO2 into formic acid with high selectivity but at high overpotential and low current density. We show that an electrochemically reduced SnO2 porous nanowire catalyst (Sn-pNWs) with a high density of grain boundaries (GBs) exhibits an energy conversion efficiency of CO2 -into-HCOOH higher than analogous catalysts. HCOOH formation begins at lower overpotential (350 mV) and reaches a steady Faradaic efficiency of ca...
February 23, 2017: Angewandte Chemie
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