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oxygen carriers

Gargi Mahapatra, Ashwathy Varughese, Qinqin Ji, Icksoo Lee, Jenney Liu, Asmita Vaishnav, Christopher Sinkler, Alexandr A Kapralov, Carlos T Moraes, Thomas H Sanderson, Timothy L Stemmler, Lawrence I Grossman, Valerian E Kagan, Joseph S Brunzelle, Arthur R Salomon, Brian F P Edwards, Maik Hüttemann
Mammalian cytochrome c (Cytc) plays a key role in cellular life and death decisions, functioning as an electron carrier in the electron transport chain (ETC) and as a trigger of apoptosis when released from the mitochondria. However, its regulation is not well understood. We show that the major fraction of Cytc isolated from kidneys is phosphorylated on Thr28, leading to a partial inhibition of respiration in the reaction with cytochrome c oxidase. To further study the effect of Cytc phosphorylation in vitro, we generated Thr28Glu phosphomimetic Cytc, revealing superior behavior regarding protein stability and its ability to degrade reactive oxygen species compared to wild-type unphosphorylated Cytc...
October 7, 2016: Journal of Biological Chemistry
Youngho Kang, Ho-Hyun Nahm, Seungwu Han
The persistent photoconductivity (PPC) in ZnO has been a critical problem in opto-electrical devices employing ZnO such as ultraviolet sensors and thin film transistors for the transparent display. While the metastable state of oxygen vacancy (VO) is widely accepted as the microscopic origin of PPC, recent experiments on the influence of temperature and oxygen environments are at variance with the VO model. In this study, using the density-functional theory calculations, we propose a novel mechanism of PPC that involves the hydrogen-zinc vacancy defect complex (2H-VZn)...
October 17, 2016: Scientific Reports
Veronika Metlenko, WooChul Jung, Sean R Bishop, Harry L Tuller, Roger A De Souza
Oxygen transport in the mixed ionic-electronic conducting perovskite-oxides SrTi1-yFeyO3-δ (with y = 0.5 and y = 1.0) was studied by oxygen isotope exchange measurements. Experiments were performed on thin-film samples that were grown by Pulsed Laser Deposition (PLD) on MgO substrates. Isotope penetration profiles were introduced by (18)O2/(16)O2 exchanges into the plane of the films at various temperatures in the range 773 < T/K < 973 at an oxygen activity aO2 = 0.5. Isotope profiles were determined subsequently by Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), and their analysis yielded tracer diffusion coefficients D* and oxygen surface exchange coefficients k*...
October 17, 2016: Physical Chemistry Chemical Physics: PCCP
Haofei I Wei, Carolina Adamo, Elizabeth A Nowadnick, Edward B Lochocki, Shouvik Chatterjee, Jacob P Ruf, Malcolm R Beasley, Darrell G Schlom, Kyle M Shen
In the cuprates, carrier doping of the Mott insulating parent state is necessary to realize superconductivity as well as a number of other exotic states involving charge or spin density waves. Cation substitution is the primary method for doping carriers into these compounds, and is the only known method for electron doping in these materials. Here, we report electron doping without cation substitution in epitaxially stabilized thin films of La_{2}CuO_{4} grown via molecular-beam epitaxy. We use angle-resolved photoemission spectroscopy to directly measure their electronic structure and conclusively determine that these compounds are electron doped with a carrier concentration of 0...
September 30, 2016: Physical Review Letters
Lukas C Buelens, Vladimir V Galvita, Hilde Poelman, Christophe Detavernier, Guy B Marin
Efficient CO2 transformation from a waste product to carbon source for chemicals and fuels will require reaction conditions that effect its reduction. We develop a "super-dry" CH4 reforming reaction for enhanced CO production from CH4 and CO2 We used Ni/MgAl2O4 as a CH4 reforming catalyst, Fe2O3/MgAl2O4 as a solid oxygen carrier, and CaO/Al2O3 as a CO2 sorbent. The isothermal coupling of these three different processes resulted in higher CO production compared with conventional dry reforming by avoiding back reactions with water...
October 13, 2016: Science
Rongrong Chen, Jiandong Fan, Chong Liu, Xing Zhang, Yanjiao Shen, Yaohua Mai
Kesterite Cu2ZnSnS4 (CZTS) semiconductor has been demonstrated to be a promising alternative absorber in thin film solar cell in virtue of its earth-abundant, non-toxic element, suitable optical and electrical properties. Herein, a low-cost and non-toxic method that based on the thermal decomposition and reaction of metal-thiourea-oxygen sol-gel complexes to synthesize CZTS thin film was developed. The low-dimensional ZnO@CdS heterojunction nano-arrays coupling with the as-prepared CZTS thin film were employed to fabricate a novel solar cell with inverted structure...
October 13, 2016: Scientific Reports
Zijian Zhang, Jun Wang, Di Liu, Wenjiao Luo, Mo Zhang, Wenjun Jiang, Yongfa Zhu
The self-assembled TCNQ-PTCDI composited photocatalyst can not only degrade phenol in the rate of 0.154 h(-1),which is 10.4 times higher than pure PTCDI; but also produce oxygen in ~14 μmol g(-1)·h(-1) without co-catalysts. The π-π interactions between TCNQ and PTCDI resulted in fast transferring of carriers and reduced the recombination. The interaction lowered valence band and narrowed band gap, thus leading to a stronger oxidizability and a broad spectral response (~730nm). Besides, the existence of TCNQ stabilized the composite for decreasing the accumulation of negative charge, which resulted in an excellent stability of the composite...
October 12, 2016: ACS Applied Materials & Interfaces
Qingshu Wang, Ling Hu, Yu Hu, Gu Gong, Hua Tan, Li Deng, Xiaoqin Sun, Xiaobo Yi, Yangyang Sun, Wei Wu, Tao Li
OBJECTIVE: To investigate the therapeutic effect of carbon monoxide (CO) on high-altitude hypoxia-induced cardiac damage. METHODS: Forty male C57BL/6 mice were randomly divided into 4 groups. The mice were exposed to normoxia or simulated 5,500-meter high-altitude hypoxia in a hypobaric chamber for 7 days. During the first 3 days, the mice were pretreated with CO-saturated hemoglobin (Hb)-based oxygen carrier (CO-HBOC), oxygen-saturated hemoglobin-based oxygen carrier (O2-HBOC) at a dose of 0...
October 12, 2016: Cardiology
M Jahurul Islam, D Amaranatha Reddy, Noh Soo Han, Jiha Choi, Jae Kyu Song, Tae Kyu Kim
An oxygen-vacancy rich, bismuth oxyiodide-based Z-scheme 3D hierarchical MoS2/BiOI/AgI ternary nanocomposite photocatalyst was fabricated using a simple precipitation process in ethylene glycol and water. The presence of oxygen-vacancies in BiOI and the two-dimensional nature of molybdenum disulfides in the composite prolongs the charge carrier lifetime through a Z-scheme system and enhances the performance of the photocatalyst for the degradation of rhodamine B. On the basis of efficient separation of photoexcited electron-hole pairs, a mechanism is proposed whereby MoS2 and oxygen vacancy states increase charge carrier lifetimes and improve the photocatalytic activity...
September 14, 2016: Physical Chemistry Chemical Physics: PCCP
Thomas Kerforne, Frédéric Favreau, Raphaël Thuillier, Thierry Hauet, Michel Pinsard
The increased number of patients in waiting list for renal transplantation requires the establishment of recommendations regarding graft preservation techniques. The preservation method impacts graft function and survival particularly in case of extended criteria donors. Based on our experience, the aim of this review is to establish a decisional diagram to draw graft management to 5years in relation to donor type and graft quality. Novel biomarkers are necessary to evaluate graft quality. Nuclear magnetic resonance or transcriptomic analyses are promising...
October 3, 2016: Néphrologie & Thérapeutique
V N Kuznetsov, N I Glazkova, R V Mikhaylov, N Serpone
This article reports an in situ UV-Vis-NIR diffuse reflectance (DR) spectroscopic and kinetic study of the photoformation and thermal annealing of light absorbing electronic point defects (color centers) in photochromic TiO2 in the temperature range 90-720 K using a simple laboratory-made cryostat-type accessory (for a Cary 5000 spectrophotometer equipped with an integrating sphere). The accessory also allowed for UV-Vis-NIR DR studies to be undertaken either in vacuum or in an oxygen atmosphere at significantly high temperatures (to 720 K) to assess dark chemical events occurring in photochromic titania with the participation of color centers...
October 5, 2016: Photochemical & Photobiological Sciences
Serena Singh, Ina S Dubinsky-Davidchik, Ronald Kluger
Conventional chemical approaches to protein-protein coupling present challenges due to the intrinsic competition between the desired interactions of reagents with groups of the protein as well as reactions with water. Biorthogonal Cu(i)-catalyzed azide-alkyne cycloaddition (CuAAC)-processes provide a basis to direct reactivity without functional group interference. However, the requirement for Cu(i) in CuAAC leads to complications that result from the metal ion's interactions with the protein. In principle, a similar but metal-free alternative approach to coupling could employ the reaction of an alkyne that is strained in combination with an azide (strain-promoted azide-alkyne cycloaddition, SPAAC)...
October 5, 2016: Organic & Biomolecular Chemistry
Xiao-Xin Gao, Qian-Qing Ge, Ding-Jiang Xue, Jie Ding, Jing-Yuan Ma, Yao-Xuan Chen, Bao Zhang, Yaqing Feng, Li-Jun Wan, Jin-Song Hu
Tuning the band alignment is proved to be an effective way to facilitate carrier transportation and thus enhance the power conversion efficiency (PCE) of solar cells. Doping the compact layer with metal ions or modifying the interfaces among functional layers in perovskite solar cells (PSCs) can appreciably improve the PCE of PSCs. Inspired by the rare earth elemental doping of TiO2, which has witnessed the success in photocatalysis and dye-sensitized solar cells, we firstly demonstrated here that La(3+) doping in the mesoporous TiO2 layer of a mesostructured PSC can tune its Fermi level and thus significantly enhance the device PCE...
September 29, 2016: Nanoscale
Yuchen Ding, Prashant Nagpal
Several strategies are currently being investigated for conversion of incident sunlight into renewable sources of energy, and photocatalytic or photoelectrochemical production of solar fuels can provide an important alternative. Titanium dioxide (TiO2) has been heavily investigated as a material of choice due to its excellent optoelectronic properties and stability, and anion-doping proposed as a pathway to improve light absorption as well as improving the efficiency of oxygen production. While several studies have used morphological tuning, elemental doping, and surface engineering in TiO2 to extend its absorption, there is a need to optimize simultaneously charge transport and improve interfacial chemical reaction kinetics...
October 14, 2016: Nanoscale
Deepanshu Srivastava, Colin Norman, Feridoon Azough, Marion C Schäfer, Emmanuel Guilmeau, Demie Kepaptsoglou, Quentin M Ramasse, Giuseppe Nicotra, Robert Freer
Ceramics based on Sr0.8La0.067Ti0.8Nb0.2O3-δ have been prepared by the mixed oxide route. The La1/3NbO3 component generates ∼13.4% A-site vacancies; this was fixed for all samples. Powders were sintered under air and reducing conditions at 1450 to 1700 K; products were of high density (>90% theoretical). Processing under reducing conditions led to the formation of a Ti1-xNbxO2-y second phase, core-shell structures and oxygen deficiency. X-ray diffraction (XRD) confirmed a simple cubic structure with space group Pm3[combining macron]m...
September 29, 2016: Physical Chemistry Chemical Physics: PCCP
Arnab Palui, Anirban Shaw, A Ghosh
We have studied the dynamics of silver ions in AgI-doped Ag2O-SeO2-MoO3 mixed former glasses in wide frequency and temperature ranges. We have observed that the ionic conductivity exhibits a mixed glass network former effect for low AgI content. The scaling for the conductivity spectra shows that the mechanism of charge carrier dynamics is independent of temperature and composition. We have obtained a mobile Ag(+) ion concentration from the Nernst-Einstein relation, which is found to be independent of temperature, but slightly dependent on composition...
September 21, 2016: Physical Chemistry Chemical Physics: PCCP
Cheolmin Park, Seung-Mo Lee, Won Seok Chang
An oxygen plasma treatment of ZnO nanostructures has frequently been used for obtaining a desired optoelectrical property. Nevertheless, a detailed study regarding carrier transport behaviors affected by the plasma has scarcely been managed, especially in the thin film structure, owing to its more complex physics than those of a one-dimensional nanostructure. Herein, we demonstrate an analysis of carrier transport behaviors on an oxygen plasma-treated ZnO nanofilm (50 nm thick) on a SiO2/Si substrate. By comparison with the as-grown sample, we observed drastic changes in carrier transport behavior according to the short exposure times of 30 s and 60 s...
September 21, 2016: Physical Chemistry Chemical Physics: PCCP
Naisheng Jiang, Levent Sendogdular, Mani Sen, Maya K Endoh, Tadanori Koga, Masafumi Fukuto, Bulent Akgun, Sushil K Satija, Chang-Yong Nam
We report the effects of compressed CO2 molecules as a novel plasticization agent for poly(3-hexylthiophene) (P3HT) conjugated polymer thin films. In-situ neutron reflectivity experiment demonstrated the excess sorption of CO2 molecules in the P3HT thin films (about 40 nm in thickness) at low pressure (P = 8.2 MPa) under the isothermal condition of T = 36 °C, which is far below the polymer bulk melting point. The results evidenced that these CO2 molecules accelerated the crystallization process of the polymer on the basis of ex-situ grazing incidence X-ray diffraction measurements after drying the films via rapid depressurization to atmospheric pressure: not only the out-of-plane lamellar ordering of the backbone chains but also intra-plane π-π stacking of the side chains were significantly improved, when compared to those in the control P3HT films subjected to conventional thermal annealing (at T = 170 °C)...
October 6, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Ying Ji, Shuo Shan, Mingyu He, Chih-Chang Chu
Amino acid-based poly(ester amide)s are a new family of biodegradable polymers that exhibit "pseudo-protein" characteristics and the structural varieties of poly(ester amide)s make them hold great potential in multiple biomedical applications. In this study, a lysine-phenylalanine-based pseudo-protein is developed as the self-assembled nanomicellar carrier for efficient delivery of doxorubicin. The lysine moieties from the pseudo-protein provide available sites for further functionalization, and methylcoumarin is introduced for easy and photocontrollable crosslinking, to effectively improve the micellar stability in serum containing environment and against dilution...
October 6, 2016: Small
Yinghui Li, Na Song, Chuanzhi Zhao, Feng Li, Miaomiao Geng, Yuhui Wang, Wanhui Liu, Chaojie Xie, Qixin Sun
Previous work has demonstrated that glycerol-3-phosphate (G3P) and oleic acid (18:1) are two important signal molecules associated with plant resistance to fungi. In this article, we provide evidence that a 3% glycerol spray application 1-2 days before powdery mildew infection and subsequent applications once every 4 days was sufficient to stimulate the plant defense responses without causing any significant damage to wheat leaves. We found that G3P and oleic acid levels were markedly induced by powdery mildew infection...
2016: Frontiers in Physiology
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