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oxygen evolution

Vera Krewald, Dimitrios A Pantazis
The pentanuclear Mn complex [Mn5(μ3-O)(bpp)6](n+) can access six consecutive total oxidation levels from Mn(ii)5 to Mn(iii)5. The electronic structure and redox behavior of this cluster are studied computationally and the results are compared with experimental data. The tunability of the redox potential span and of the absolute potential position is explored through systematic modifications of the 3,5-bis(pyridin-2-yl)-pyrazole (Hbpp) ligand. By substitutions with electron-donating and electron-withdrawing groups, the position of the redox events can be shifted by ca...
October 24, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Jongsik Park, Jongchan Kim, Yoojin Yang, Donghwan Yoon, Hionsuck Baik, Seungjoo Haam, Haesik Yang, Kwangyeol Lee
One pot synthesis of RhCu alloy truncated octahedral nanoframes, Cu@Rh core-shell nanoparticles, and a bundle of five RhCu nanowires is demonstrated. The RhCu alloy 3D nanoframe, in particular, exhibits excellent catalytic activity toward the oxygen evolution reaction under alkaline conditions.
April 2016: Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
Xiaomin Xu, Chao Su, Wei Zhou, Yinlong Zhu, Yubo Chen, Zongping Shao
A synergistic co-doping strategy is proposed to identify a series of BaCo0.9-x Fe x Sn0.1O3-δ perovskites with tunable electrocatalytic activity for the oxygen evolution reaction (OER). Simply through tailoring the relative concentrations of less OER-active tin and iron dopants, a cubic perovskite structure (BaCo0.7Fe0.2Sn0.1O3-δ) is stabilized, showing intrinsic OER activity >1 order of magnitude larger than IrO2 and a Tafel slope of 69 mV dec(-1).
February 2016: Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
J Y Dong, F Song, Y K Liu, X Q Wang
Objective: To simulate the environmental factors during the process of formation and evolution of hypertrophic scar, so as to explore the effects of moderate and severe hypoxia and low concentration of serum protein on the function of human hypertrophic scar fibroblasts (HSFs). Methods: Human HSFs were routinely cultured. Cells of the 3rd to the 6th passage were divided into 10.0% oxygen+ 10.0% fetal calf serum (FCS), 5.0% oxygen+ 5.0% FCS, and 0.5% oxygen+ 0.5% FCS groups according to the random number table...
October 20, 2016: Zhonghua Shao Shang za Zhi, Zhonghua Shaoshang Zazhi, Chinese Journal of Burns
Zhe Lv, Nasir Mahmood, Muhammad Tahir, Lun Pan, Xiangwen Zhang, Ji-Jun Zou
Transition metal dichalcogenides (TMDs) are emerging as promising materials, particularly for electrochemical and photochemical catalytic applications, and among them molybdenum sulfides have received tremendous attention due to their novel electronic and optoelectronic characteristics. Several review articles have summarized the recent progress on TMDs but no critical and systematic summary exists about the nanoscale fabrication of MoS2 with different dimensional morphologies. In this review article, first we will summarize the recent progress on the morphological tuning and structural evolution of MoS2 from zero-dimension (0D) to 3D...
October 20, 2016: Nanoscale
Vojtěch Žárský, Pavel Doležal
BACKGROUND: The Tim17 family of proteins plays a fundamental role in the biogenesis of mitochondria. Three Tim17 family proteins, Tim17, Tim22, and Tim23, are the central components of the widely conserved multi-subunit protein translocases, TIM23 and TIM22, which mediate protein transport across and into the inner mitochondrial membrane, respectively. In addition, several Tim17 family proteins occupy the inner and outer membranes of plastids. RESULTS: We have performed comprehensive sequence analyses on 5631 proteomes from all domains of life deposited in the Uniprot database...
October 19, 2016: Biology Direct
Jooyeon Jeong, Kwangryul Baek, Henning Kirst, Anastasios Melis, EonSeon Jin
The Chlamydomonas reinhardtii truncated light-harvesting antenna 4 (tla4) DNA transposon mutant has a pale green phenotype, a lower chlorophyll (Chl) per cell and a higher Chl a/b ratio in comparison with the wild type. It required a higher light intensity for the saturation of photosynthesis and displayed a greater per chlorophyll light-saturated rate of oxygen evolution than the wild type. The Chl antenna size of the photosystems in the tla4 mutant was only about 65% of that measured in the wild type. Molecular genetic analysis revealed that a single plasmid DNA insertion disrupted two genes on chromosome 11 of the mutant...
October 17, 2016: Biochimica et Biophysica Acta
Won-Hee Ryu, Forrest S Gittleson, Julianne M Thomsen, Jinyang Li, Mark J Schwab, Gary W Brudvig, André D Taylor
One of the greatest challenges with lithium-oxygen batteries involves identifying catalysts that facilitate the growth and evolution of cathode species on an oxygen electrode. Heterogeneous solid catalysts cannot adequately address the problematic overpotentials when the surfaces become passivated. However, there exists a class of biomolecules which have been designed by nature to guide complex solution-based oxygen chemistries. Here, we show that the heme molecule, a common porphyrin cofactor in blood, can function as a soluble redox catalyst and oxygen shuttle for efficient oxygen evolution in non-aqueous Li-O2 batteries...
October 19, 2016: Nature Communications
Chenyi Cai, Min Kuang, Xiling Chen, Hao Wu, Hongtao Ge, Gengfeng Zheng
The development of efficient and robust electrocatalyst has been the central of the solar water splitting-based hydrogen fuel acquisition. In this work, we reported the use of cow milk, with addition of tetraethyl orthosilicate (TEOS) and melamine, for the synthesis of nitrogen-doped mesoporous carbon microspheres. Due to the large surface and enhanced charge transport behavior, the obtained samples enabled low overpotentials and a small Tafel slope toward oxygen evolution reaction, which were close or comparable to the best OER catalysts of carbon materials reported previously...
October 12, 2016: Journal of Colloid and Interface Science
Tingting Wu, James D Englehardt
An urban net-zero water treatment system, designed for energy-positive water management, 100% recycle of comingled black/grey water to drinking water standards, and mineralization of hormones and other organics, without production of concentrate, was constructed and operated for two years, serving an occupied four-bedroom, four-bath university residence hall apartment. The system comprised septic tank, denitrifying membrane bioreactor (MBR), iron-mediated aeration (IMA) reactor, vacuum ultrafilter, and peroxone or UV/H2O2 advanced oxidation, with 14% rainwater make-up and concomitant discharge of 14% of treated water (ultimately for reuse in irrigation)...
October 5, 2016: Water Research
Naoji Yubuki, Eliška Zadrobílková, Ivan Čepička
Fornicata (Metamonada) is a group of Excavata living in low oxygen environments and lacking conventional mitochondria. It includes free-living Carpediemonas-like organisms from marine habitats and predominantly parasitic/commensal retortamonads and diplomonads. Current modest knowledge of biodiversity of Fornicata limits our ability to draw a complete picture of the evolutionary history in this group. Here, we report the discovery of a novel fornicate, Iotanema spirale gen. nov. et sp. nov., obtained from fresh feces of the gecko Phelsuma madagascariensis...
October 17, 2016: Journal of Eukaryotic Microbiology
Zhaohui Xiao, Xiaobing Huang, Lei Xu, Dafeng Yan, Jia Huo, Shuangyin Wang
The development of efficient, stable and cost-effective electrocatalysts for the oxygen evolution reaction (OER) is the key for water splitting. Carbon-based nanomaterials have found significant applications as metal-free OER electrocatalysts. In this study, for the first time, edge-selectively phosphorus-doped graphene (G-P) was synthesised for OER electrocatalysts. The G-P catalyst reached a current density of 10 mA cm(-2) at a small overpotential of 330 mV for the OER with a Tafel slope as low as 62 mV dec(-1), which is superior to most of the carbon-based electrocatalysts reported to date...
October 17, 2016: Chemical Communications: Chem Comm
Carien Coetzee, Elizma Van Wyngaard, Katja Šuklje, Antonio C Silva Ferreira, Wessel J du Toit
The effect of repetitive controlled oxidation on the chemical and sensory composition of a fresh and fruity style Sauvignon blanc wine was investigated. Chemical analyses were conducted together with extensive sensory profiling. A decrease in volatile thiols responsible for the fruity nuances and an increase in oxidation-related compounds, such as acetaldehyde, during the course of the oxidation was observed. The wine evolved from a fresh and fruity one to one with slight oxidation and then developed extreme oxidative characteristics...
October 17, 2016: Journal of Agricultural and Food Chemistry
Madhuri A Inupakutika, Soham Sengupta, Amith R Devireddy, Rajeev K Azad, Ron Mittler
Reactive oxygen species (ROS) play a key role in the regulation of many biological processes in plants. Nonetheless, they are considered highly reactive and toxic to cells. Owing to their toxicity, as well as their important role in signaling, the level of ROS in cells needs to be tightly regulated. The ROS gene network, encoding a highly redundant arsenal of ROS scavenging mechanisms and an array of enzymes involved in ROS production, regulates ROS metabolism and signaling in plants. In this article, we review the role of the ROS gene network in plants and examine how it evolved...
October 14, 2016: Journal of Experimental Botany
Ibrahim Saana Amiinu, Jian Zhang, Zongkui Kou, Xiaobo Liu, Owusu Kwadwo Asare, Huang Zhou, Kun Cheng, Haining Zhang, Liqiang Mai, Mu Pan, Shichun Mu
3D graphene-based materials offer immense potentials to overcome the challenges related to the functionality, performance, cost, and stability of fuel cell electrocatalysts. Herein, a nitrogen (N) and sulfur (S) dual-doped 3D porous graphene catalyst is synthesized via a single-row pyrolysis using biomass as solitary source for both N and S, and a structure directing agent. The thermochemical reaction of biomass functional groups with graphene oxide facilitates in situ generation of reactive N and S species, stimulating the graphene layers to reorganize into a trimodal 3D porous assembly...
October 14, 2016: ACS Applied Materials & Interfaces
Chaohe Xu, Meihua Lu, Binggong Yan, Yi Zhan, Palani Balaya, Li Lu, Jim Yang Lee
The rational design of nonprecious-metal electrocatalysts with activities comparable to or greater than that of platinum is extremely valuable to the development of high energy density metal-air batteries. Herein, the two-step preparation of a highly active oxygen electrocatalyst based on ultrasmall cobalt nanoparticles stabilized in a nitrogen-doped graphene matrix is reported. The catalyst performs as well as the commercial Pt/C catalyst in the oxygen reduction reaction, and better than the Pt/C catalyst in the oxygen evolution reaction...
October 14, 2016: ChemSusChem
Fuminao Kishimoto, Masayuki Matsuhisa, Shinichiro Kawamura, Satoshi Fujii, Shuntaro Tsubaki, Masato M Maitani, Eiichi Suzuki, Yuji Wada
Various microwave effects on chemical reactions have been observed, reported and compared to those carried out under conventional heating. These effects are classified into thermal effects, which arise from the temperature rise caused by microwaves, and non-thermal effects, which are attributed to interactions between substances and the oscillating electromagnetic fields of microwaves. However, there have been no direct or intrinsic demonstrations of the non-thermal effects based on physical insights. Here we demonstrate the microwave enhancement of oxidation current of water to generate dioxygen with using an α-Fe2O3 electrode induced by pulsed microwave irradiation under constantly applied potential...
October 14, 2016: Scientific Reports
Elia Marin, Alfredo Rondinella, Wenliang Zhu, Bryan J McEntire, B Sonny Bal, Giuseppe Pezzotti
The effect of frictional sliding on the surface degradation of commercially available zirconia-toughened alumina (ZTA) femoral heads was studied using a pin-on-ball wear tester under three different lubricating conditions: dry, water, and squalene. Water and squalene were employed under boundary lubrication regimes. Despite the unique (non-standard) character of this apparatus, standard loading conditions could be applied, which effectively determined dynamic friction coefficients as basic material properties...
September 28, 2016: Journal of the Mechanical Behavior of Biomedical Materials
Zhishan Luo, Sara Martí-Sànchez, Raquel Nafria, Gihan S Joshua, María de la Mata, Pablo Guardia, Cristina Flox, Carlos Martinez-Boubeta, Konstantinos Simeonidis, Jordi Llorca, Joan Ramon Morante, Jordi Arbiol, Maria Ibáñez, Andreu Cabot
The design and engineering of earth-abundant catalysts that are both cost-effective and highly active for water splitting is a crucial challenge in a number of energy conversion and storage technologies. In this direction, herein we report the synthesis of Fe3O4@NiFexOy core-shell nano-heterostructures and the characterization of their electrocatalytic performance toward the oxygen evolution reaction (OER). Such nanoparticles (NPs) were produced by a two-step synthesis procedure involving the colloidal synthesis of Fe3O4 nanocubes with a defective shell and the posterior diffusion of nickel cations within this defective shell...
October 12, 2016: ACS Applied Materials & Interfaces
François Olivier, Sophie Nadeau, Georges Caouette, Bruno Piedboeuf
BACKGROUND: Late preterm infants (34-36 weeks' gestation) remain a population at risk for apnea of prematurity (AOP). As infants affected by respiratory distress syndrome (RDS) have immature lungs, they might also have immature control of breathing. Our hypothesis is that an association exists between RDS and AOP in late preterm infants. OBJECTIVE: The primary objective of this study was to assess the association between RDS and AOP in late preterm infants. The secondary objective was to evaluate if an association exists between apparent RDS severity and AOP...
2016: Frontiers in Pediatrics
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