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https://www.readbyqxmd.com/read/28106164/diverse-strategies-of-o2-usage-for-preventing-photo-oxidative-damage-under-co2-limitation-during-algal-photosynthesis
#1
Ginga Shimakawa, Yusuke Matsuda, Kensuke Nakajima, Masahiro Tamoi, Shigeru Shigeoka, Chikahiro Miyake
Photosynthesis produces chemical energy from photon energy in the photosynthetic electron transport and assimilates CO2 using the chemical energy. Thus, CO2 limitation causes an accumulation of excess energy, resulting in reactive oxygen species (ROS) which can cause oxidative damage to cells. O2 can be used as an alternative energy sink when oxygenic phototrophs are exposed to high light. Here, we examined the responses to CO2 limitation and O2 dependency of two secondary algae, Euglena gracilis and Phaeodactylum tricornutum...
January 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28106126/bi-axial-grown-amorphous-mosx-bridged-with-oxygen-on-r-go-as-a-superior-stable-and-efficient-nonprecious-catalyst-for-hydrogen-evolution
#2
Cheol-Ho Lee, Jin-Mun Yun, Sungho Lee, Seong Mu Jo, KwangSup Eom, Doh C Lee, Han-Ik Joh, Thomas F Fuller
Amorphous molybdenum sulfide (MoSx) is covalently anchored to reduced graphene oxide (r-GO) via a simple one-pot reaction, thereby inducing the reduction of GO and simultaneous doping of heteroatoms on the GO. The oxygen atoms form a bridged between MoSx and GO and play a crucial role in the fine dispersion of the MoSx particles, control of planar MoSx growth, and increase of exposed active sulfur sites. This bridging leads to highly efficient (-157 mV overpotential and 41 mV/decade Tafel slope) and stable (95% versus initial activity after 1000 cycles) electrocatalyst for hydrogen evolution...
January 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28105829/gastight-hydrodynamic-electrochemistry-design-for-a-hermetically-sealed-rotating-disk-electrode-cell
#3
Suho Jung, Ruud Kortlever, Ryan J R Jones, Michael F Lichterman, Theodor Agapie, Charles C L McCrory, Jonas C Peters
Rotating disk electrodes (RDEs) are widely used in electrochemical characterization to analyze the mechanisms of various electrocatalytic reactions. RDE experiments often make use of or require collection and quantification of gaseous products. The combination of rotating parts and gaseous analytes makes the design of RDE cells that allow for headspace analysis challenging due to gas leaks at the interface of the cell body and the rotator. In this manuscript we describe a new, hermetically sealed electrochemical cell that allows for electrode rotation while simultaneously providing a gastight environment...
January 3, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28105685/evolution-of-gas-permeable-membranes-for-extracorporeal-membrane-oxygenation
#4
REVIEW
Torin Yeager, Shuvo Roy
Gas permeable membranes are a vital component of extracorporeal membrane oxygenation systems. Over more than half a century, membrane fabrication and packaging technology have progressed to enable safer and longer duration use of respiratory life support. Current research efforts seek to improve membrane efficiency and hemocompatibility, with the aim of producing smaller and more robust systems for ambulatory use. This review explores past and present innovations in oxygenator technology, suggesting possible applications of state-of-the-art membrane fabrication methods to address shortcomings of earlier concepts...
January 19, 2017: Artificial Organs
https://www.readbyqxmd.com/read/28103245/anaerobically-grown-escherichia-coli-has-an-enhanced-mutation-rate-and-distinct-mutational-spectra
#5
Sonal Shewaramani, Thomas J Finn, Sinead C Leahy, Rees Kassen, Paul B Rainey, Christina D Moon
Oxidative stress is a major cause of mutation but little is known about how growth in the absence of oxygen impacts the rate and spectrum of mutations. We employed long-term mutation accumulation experiments to directly measure the rates and spectra of spontaneous mutation events in Escherichia coli populations propagated under aerobic and anaerobic conditions. To detect mutations, whole genome sequencing was coupled with methods of analysis sufficient to identify a broad range of mutational classes, including structural variants (SVs) generated by movement of repetitive elements...
January 19, 2017: PLoS Genetics
https://www.readbyqxmd.com/read/28103106/low-temperature-alkaline-ph-hydrolysis-of-oxygen-free-titan-tholins-carbonates-impact
#6
Coralie Brassé, Arnaud Buch, Patrice Coll, François Raulin
Titan, the largest moon of Saturn, is one of the key planetary objects in the field of exobiology. Its dense, nitrogen-rich atmosphere is the site of important organic chemistry. This paper focuses on the organic aerosols produced in Titan's atmosphere that play an important role in atmospheric and surface processes and in organic chemistry as it applies to exobiological interests. To produce reliable laboratory analogues of these aerosols, we developed, tested, and optimized a device for the synthesis of clean tholins...
January 2017: Astrobiology
https://www.readbyqxmd.com/read/28103105/evolution-of-earth-like-extrasolar-planetary-atmospheres-assessing-the-atmospheres-and-biospheres-of-early-earth-analog-planets-with-a-coupled-atmosphere-biogeochemical-model
#7
S Gebauer, J L Grenfell, J W Stock, R Lehmann, M Godolt, P von Paris, H Rauer
Understanding the evolution of Earth and potentially habitable Earth-like worlds is essential to fathom our origin in the Universe. The search for Earth-like planets in the habitable zone and investigation of their atmospheres with climate and photochemical models is a central focus in exoplanetary science. Taking the evolution of Earth as a reference for Earth-like planets, a central scientific goal is to understand what the interactions were between atmosphere, geology, and biology on early Earth. The Great Oxidation Event in Earth's history was certainly caused by their interplay, but the origin and controlling processes of this occurrence are not well understood, the study of which will require interdisciplinary, coupled models...
January 2017: Astrobiology
https://www.readbyqxmd.com/read/28102962/general-synthesis-of-multishell-mixed-metal-oxyphosphide-particles-with-enhanced-electrocatalytic-activity-in-the-oxygen-evolution-reaction
#8
Bu Yuan Guan, Le Yu, Xiong Wen David Lou
We report a general approach for the synthesis of multishell mixed-metal oxyphosphide particles. Seven-layer Mn-Co oxide particles were first prepared by thermal treatment of Mn-Co coordination polymer precursors. Afterwards, these multishell Mn-Co oxide particles were further transformed into multishell Mn-Co oxyphosphide particles through a phosphidation reaction. This approach is very versatile and can be applied to synthesize other multishell mixed-metal oxyphosphide particles with different compositions...
January 19, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28102612/nickel-nanoparticles-encapsulated-in-few-layer-nitrogen-doped-graphene-derived-from-metal-organic-frameworks-as-efficient-bifunctional-electrocatalysts-for-overall-water-splitting
#9
You Xu, Wenguang Tu, Bowei Zhang, Shengming Yin, Yizhong Huang, Markus Kraft, Rong Xu
Nickel nanoparticles encapsulated in few-layer nitrogen-doped graphene (Ni@NC) have been synthesized by using a Ni-based metal-organic framework as the precursor for high-temperature annealing treatment. The resulting Ni@NC materials exhibit highly efficient and ultrastable electrocatalytic activity toward hydrogen evolution reaction and oxygen evolution reaction as well as overall water splitting in alkaline environment.
January 19, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28101949/highly-active-three-dimensional-nife-cu2o-nanowires-cu-foam-electrode-for-water-oxidation
#10
Yan Gao, Hu Chen, Licheng Sun
Water splitting is of paramount importance for exploiting renewable energy conversion and storage systems, but is greatly hindered by the kinetically sluggish oxygen evolution reaction. Here, we develop a three-dimensional, greatly efficient and durable NiFe/Cu2O nanowires/Cu foam anode (NiFe/Cu2O NWs/CF) for water oxidation in 1.0 M KOH. The obtained electrode exhibited a current density of 10 mA/cm2 at a uniquely low overpotential of 215 mV and can keep a steady current density of 100 mA/cm2 for 50 h at an overpotential of 260 mV...
January 18, 2017: ChemSusChem
https://www.readbyqxmd.com/read/28098444/a-heterogeneous-electrocatalyst-with-molecular-cobalt-ions-serving-as-the-center-of-active-sites
#11
Jiong Wang, Xiaoming Ge, Zhaolin Liu, Larissa Thia, Ya Yan, Wei Xiao, Xin Wang
Molecular Co2+ ions were grafted onto doped graphene in a coordination environment, resulting in the formation of molecularly well-defined, highly active electrocatalytic sites at a heterogeneous interface for the oxygen evolution reaction (OER). The S dopants of graphene are suggested to be one of the binding sites and to be responsible for improving the intrinsic activity of the Co sites. The turnover frequency of such Co sites is greater than that of many Co-based nanostructures and IrO2 catalysts. Through a series of carefully designed experiments, the pathway for the evolution of the Co cation-based molecular catalyst for the OER was further demonstrated on such a single Co-ion site for the first time...
January 18, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28096405/selenium-isotopes-record-extensive-marine-suboxia-during-the-great-oxidation-event
#12
Michael A Kipp, Eva E Stüeken, Andrey Bekker, Roger Buick
It has been proposed that an "oxygen overshoot" occurred during the early Paleoproterozoic Great Oxidation Event (GOE) in association with the extreme positive carbon isotopic excursion known as the Lomagundi Event. Moreover, it has also been suggested that environmental oxygen levels then crashed to very low levels during the subsequent extremely negative Shunga-Francevillian carbon isotopic anomaly. These redox fluctuations could have profoundly influenced the course of eukaryotic evolution, as eukaryotes have several metabolic processes that are obligately aerobic...
January 17, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28094494/structural-evolution-induced-by-interfacial-lattice-mismatch-in-self-organized-yba2cu3o7-%C3%AE-nanocomposite-film
#13
Tomoya Horide, Fumitake Kametani, Satoru Yoshioka, Takanori Kitamura, Kaname Matsumoto
Intriguing properties of self-organized nanocomposites of perovskite oxides are usually derived from the complex interface of constituent material phases. A sophisticated control of such a system is required for a broad range of energy and device applications, which demand a comprehensive understanding of the interface at the atomic scale. Here, we visualized and theoretically modeled the highly elastically strained nanorod, the interface region with misfit dislocations and heterointerface distortion, and the matrix with strain-induced oxygen vacancies in the self-organized YBa2Cu3O7-δ nanocomposite films with Ba perovskite nanorods...
January 17, 2017: ACS Nano
https://www.readbyqxmd.com/read/28094367/formation-of-carbon-nanodots-with-different-spin-states-in-mechanically-processed-mixtures-of-zno-with-carbon-nanoparticles-an-electron-paramagnetic-resonance-study
#14
M Kakazey, M Vlasova, V Gómez-Vidales, A Ángeles-Pascual, V A Basiuk
Mixtures of zinc oxide with carbon nanoparticles, ZnO + xC (x = 0.1%, 1% and 3% by weight), were subjected to mechanical processing (MP) in a hermetically sealed grinding chamber. Using electron paramagnetic resonance (EPR) spectroscopy, we monitored the evolution of spin centers in CNPs. While the initial CNPs were EPR silent, their short-duration MP (tMP) gave rise to emergence of low-intensity carbon signal. Increasing the sample temperature at tMP > 9 min induced CNP oxidation, which lead to a dramatic increase in the intensity of C signal...
January 17, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28092755/coagulation-flocculation-sequential-with-fenton-or-photo-fenton-processes-as-an-alternative-for-the-industrial-textile-wastewater-treatment
#15
Edison GilPavas, Izabela Dobrosz-Gómez, Miguel Ángel Gómez-García
In this study, the industrial textile wastewater was treated using a chemical-based technique (coagulation-flocculation, C-F) sequential with an advanced oxidation process (AOP: Fenton or Photo-Fenton). During the C-F, Al2(SO4)3 was used as coagulant and its optimal dose was determined using the jar test. The following operational conditions of C-F, maximizing the organic matter removal, were determined: 700 mg/L of Al2(SO4)3 at pH = 9.96. Thus, the C-F allowed to remove 98% of turbidity, 48% of Chemical Oxygen Demand (COD), and let to increase in the BOD5/COD ratio from 0...
January 13, 2017: Journal of Environmental Management
https://www.readbyqxmd.com/read/28092389/a-new-method-for-developing-defect-rich-graphene-nanoribbons-onion-like-carbon-co-nanoparticles-hybrid-materials-as-an-excellent-catalyst-for-oxygen-reactions
#16
Wenxiu Yang, Lulu Chen, Xiangjian Liu, Jianbo Jia, Shaojun Guo
Herein, a novel material with an excellent electrocatalytic activity for the oxygen reduction reaction (ORR), composed of onion-like carbon@Co nanoparticles (NPs) incorporated on defect-rich N-doped graphene nanoribbons (C@Co-NGR), is prepared via a combination of nitric acid etching and subsequent high-temperature treatment of the as-synthesized C@Co-N doped carbon nanotubes. The as-prepared C@Co-NGR exhibits excellent electrocatalytic activity for the ORR in 0.10 M KOH with a half-wave potential of 0.830 V (vs...
January 16, 2017: Nanoscale
https://www.readbyqxmd.com/read/28092008/spatio-temporal-variation-of-septage-characteristics-of-a-semi-arid-metropolitan-city-in-a-developing-country
#17
D Krithika, Anu Rachel Thomas, Gomathy R Iyer, Martin Kranert, Ligy Philip
Septage is the solid sludge that accumulates in septic tanks over a period of time. Many of the developing countries in the world face the challenging task of septage management. Due to the high variability in the nature of septage, there is a need to study its physical and chemical characteristics in order to suggest a sustainable treatment methodology. The present study deals with the characterization of septage collected from different locations of Chennai city in India, in two different seasons (summer and winter)...
January 16, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28091552/dual-sources-of-water-overprinting-on-the-low-zircon-%C3%AE-18-o-metamorphic-country-rocks-disequilibrium-constrained-through-inverse-modelling-of-partial-reequilibration
#18
Chun-Sheng Wei, Zi-Fu Zhao
Since water is only composed of oxygen and hydrogen, δ(18)O and δ(2)H values are thus utilized to trace the origin of water(s) and quantify the water-rock interactions. While Triassic high pressure (HP) and ultrahigh pressure (UHP) metamorphic rocks across the Dabie-Sulu orogen in central-eastern China have been well documented, postcollisional magmatism driven hydrothermal systems are little known. Here we show that two sources of externally derived water interactions were revealed by oxygen isotopes for the gneissic country rocks intruded by the early Cretaceous postcollisional granitoids...
January 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28089874/mathematical-modelling-of-cell-layer-growth-in-a-hollow-fibre-bioreactor
#19
Lloyd A C Chapman, Jonathan P Whiteley, Helen M Byrne, Sarah L Waters, Rebecca J Shipley
Generating autologous tissue grafts of a clinically useful volume requires efficient and controlled expansion of cell populations harvested from patients. Hollow fibre bioreactors show promise as cell expansion devices, owing to their potential for scale-up. However, further research is required to establish how to specify appropriate hollow fibre bioreactor operating conditions for expanding different cell types. In this study we develop a simple model for the growth of a cell layer seeded on the outer surface of a single fibre in a perfused hollow fibre bioreactor...
January 12, 2017: Journal of Theoretical Biology
https://www.readbyqxmd.com/read/28088333/mitochondrial-uncoupling-in-cancer-cells-liabilities-and-opportunities
#20
REVIEW
Gyorgy Baffy
Acquisition of the endosymbiotic ancestor of mitochondria was a critical event in eukaryote evolution. Mitochondria offered an unparalleled source of metabolic energy through oxidative phosphorylation and allowed the development of multicellular life. However, as molecular oxygen had become the terminal electron acceptor in most eukaryotic cells, the electron transport chain proved to be the largest intracellular source of superoxide, contributing to macromolecular injury, aging, and cancer. Hence, the 'contract of endosymbiosis' represents a compromise between the possibilities and perils of multicellular life...
January 11, 2017: Biochimica et Biophysica Acta
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