Dinitrogen Fixation Within and Adjacent to Oxygen Deficient Waters of the Eastern Tropical South Pacific Ocean

Science.gov (United States)

Widner, B.; Mulholland, M. R.; Bernhardt, P. W.; Chang, B. X.; Jayakumar, A.

2016-02-01

Recent work suggests that planktonic diazotrophs are geographically more widely distributed than previously thought including relatively warm (14-23oC) aphotic oxygenated pelagic waters and in aphotic waters within oxygen deficient zones. Because the volume of aphotic water in the ocean is large and may increase in the future, if dinitrogen (N2) fixation is widely occurring at sub-euphotic depths, this could result in a dramatic upward revision of global nitrogen (N) inputs via this process. N2 fixation rates were measured during a cruise in the Eastern Tropical South Pacific using stable isotope tracer techniques that account for slow gas dissolution. Results are compared with light, nutrient, and oxygen gradients (and necessarily temperature gradients). In addition, rates of N2 fixation made in vertical profiles within and above oxygen deficient waters are compared with those measured in vertical profiles adjacent to oxygen deficient waters. Results suggest that while rates of N2 fixation were measurable in deeper anoxic waters, volumetric N2 fixation rates were higher in surface waters.

Oxygen deficiency in MoO{sub 3} polycrystalline nanowires and nanotubes

Energy Technology Data Exchange (ETDEWEB)

Varlec, Ana, E-mail: ana.varlec@ijs.si [Condensed Matter Physics, Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Arčon, Denis [Condensed Matter Physics, Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Faculty of Mathematics and Physics, University of Ljubljana, Jadranska cesta 19, SI-1000 Ljubljana (Slovenia); Škapin, Srečo D. [Advanced Materials Department, Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Remškar, Maja [Condensed Matter Physics, Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia)

2016-02-15

We report on the synthesis of polycrystalline molybdenum oxide (MoO{sub 3}) nanowires via oxidation of molybdenum-sulfur-iodine (Mo{sub 6}S{sub 2}I{sub 8}) nanowires. This unique synthesis route results in an interesting morphology comprising porous nanowires and nanotubes. We found the nanowires to have the orthorhombic MoO{sub 3} structure. The structure is slightly oxygen deficient which results in the appearance of a new resonant Raman band (1004 cm{sup −1}) and paramagnetic defects (Mo{sup 5+}) of both the point and crystallographic shear plane nature. - Highlights: • Polycrystalline MoO{sub 3} nanowires were obtained via oxidation of Mo{sub 6}S{sub 2}I{sub 8} nanowires. • Nanowires are porous and tubular with either filled or empty interior. • Nanowires are slightly oxygen deficient which leads to a new Raman band.

Deficient by oxygen perovskites and superconductor with transition temperature 93 K

International Nuclear Information System (INIS)

Ross, N.L.; Angel, R.J.; Finger, L.W.; Hazen, R.M.; Prewitt, K.T.

1988-01-01

Structural changes in some perovskites deficient by oxygen is reviewd. The structure of the high-temperature YBa 2 Cu 3 O 7-x superconductor is shown to develop usual for perovskites properties and at the same time to possess specific features. The specific feature includes the fact that ordering of vacancies and oxygen atoms is the consequence of Ba 2+ and Y 3+ ordering in positions A. Such ordering causes the removal of oxygen atoms plane from the structure and accurrence of pyramidal-coordinated atoms Cu2 in positions B. 22 refs.; 3 figs.; 2 tabs

Effect of oxygen deficiency on electronic properties and local structure of amorphous tantalum oxide thin films

Energy Technology Data Exchange (ETDEWEB)

Denny, Yus Rama [Department of Physics Education, University of Sultan Ageng Tirtayasa, Banten 42435 (Indonesia); Firmansyah, Teguh [Department of Electrical Engineering, University of Sultan Ageng Tirtayasa, Banten 42435 (Indonesia); Oh, Suhk Kun [Department of Physics, Chungbuk National University, Cheongju 28644 (Korea, Republic of); Kang, Hee Jae, E-mail: hjkang@cbu.ac.kr [Department of Physics, Chungbuk National University, Cheongju 28644 (Korea, Republic of); Yang, Dong-Seok [Department of Physics Education, Chungbuk National University, Cheongju 28644 (Korea, Republic of); Heo, Sung; Chung, JaeGwan; Lee, Jae Cheol [Analytical Engineering Center, Samsung Advanced Institute of Technology, Suwon 16678 (Korea, Republic of)

2016-10-15

Highlights: • The effect of oxygen flow rate on electronic properties and local structure of tantalum oxide thin films was studied. • The oxygen deficiency induced the nonstoichiometric state a-TaOx. • A small peak at 1.97 eV above the valence band side appeared on nonstoichiometric Ta{sub 2}O{sub 5} thin films. • The oxygen flow rate can change the local electronic structure of tantalum oxide thin films. - Abstract: The dependence of electronic properties and local structure of tantalum oxide thin film on oxygen deficiency have been investigated by means of X-ray photoelectron spectroscopy (XPS), Reflection Electron Energy Loss Spectroscopy (REELS), and X-ray absorption spectroscopy (XAS). The XPS results showed that the oxygen flow rate change results in the appearance of features in the Ta 4f at the binding energies of 23.2 eV, 24.4 eV, 25.8, and 27.3 eV whose peaks are attributed to Ta{sup 1+}, Ta{sup 2+}, Ta{sup 3+}/Ta{sup 4+}, and Ta{sup 5+}, respectively. The presence of nonstoichiometric state from tantalum oxide (TaOx) thin films could be generated by the oxygen vacancies. In addition, XAS spectra manifested both the increase of coordination number of the first Ta-O shell and a considerable reduction of the Ta-O bond distance with the decrease of oxygen deficiency.

Effect of oxygen deficiency on the magnetic field-dependent entropy ...

Indian Academy of Sciences (India)

Moreover, to account for the applicability of the theory at high field, we have incorporated the effect of vortex overlapping in the London theory done by Nanda (1995). Here, we have presented the variation of change in entropy (S) with magnetic field for different oxygen deficiencies = 0, 0.04, and 0.06. On comparison ...

Facile Aluminum Reduction Synthesis of Blue TiO2 with Oxygen Deficiency for Lithium-Ion Batteries.

Science.gov (United States)

Zheng, Jing; Ji, Guangbin; Zhang, Peng; Cao, Xingzhong; Wang, Baoyi; Yu, Linghui; Xu, Zhichuan J

2015-12-07

An ultrafacile aluminum reduction method is reported herein for the preparation of blue TiO2 nanoparticles (donated as Al-TiO2 , anatase phase) with abundant oxygen deficiency for lithium-ion batteries. Under aluminum reduction, the morphology of the TiO2 nanosheets changes from well-defined rectangular into uniform round or oval nanoparticles and the particle size also decreases from 60 to 31 nm, which can aggressively accelerate the lithium-ion diffusion. Electron paramagnetic resonance (EPR) and positron annihilation lifetime spectroscopy (PALS) results reveal that plentiful oxygen deficiencies relative to the Ti(3+) species were generated in blue Al-TiO2 ; this effectively enhances the electron conductivity of the TiO2 . X-ray photoelectron spectrometry (XPS) analysis indicates that a small peak is observed for the Al-O bond, which probably plays a very important role in the stabilization of the oxygen deficiencies/Ti(3+) species. As a result, the blue Al-TiO2 possesses significantly higher capacity, better rate performance, and a longer cycle life than the white pure TiO2 . Such improvements can be attributed to the decreased particle size, as well as the existence of the oxygen deficiencies/Ti(3+) species. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Oxygen Stoichiometry in Cation Deficient (La,Sr)_{1-z}MnO_3 SOFC Cathode Materials

DEFF Research Database (Denmark)

Zachau-Christiansen, Birgit; Jacobsen, Torben; Skaarup, Steen

1997-01-01

by the imposed potential.It is found that the oxygen stoichiometry and hence the defect chemistry is different whether A-site charge deficiency is established by Sr-doping or by A-site vacancies. Furthermore,A-site deficient lanthanum strontium manganates expel a secondary phase of manganese oxide when exposed...... to low oxygen partial pressures. The presence of small amounts of secondary phase isobserved and identified by its reoxidation peak. The amount of this foreign phase is determined by the charge used for its oxidation....

High-temperature vaporization behavior of oxygen-deficient thoria

International Nuclear Information System (INIS)

Ackermann, R.J.; Tetenbaum, M.

1979-01-01

The experimental results of the present study on the vaporization behavior of oxygen-deficient thoria are directed toward a more precise and detailed study of the lower phase boundary (l.p.b.) and congruently vaporizing composition (c.v.c), and intermediate compositions, and the corresponding oxygen potentials and total pressure at temperatures above 2000K. The l.p.b. and c.v.c. values were found to fit an equation of the form log x = A + (B/T), where x is the stoichiometric defect in ThO 2 -x. Oxygen potentials corresponding to the l.p.b. and c.v.c. have been estimated from vapor pressures and thermodynamic data. A very sharp decrease in oxygen potential occurs when thoria isreduced only slightly from the stoichiometric composition. In the temperature range from 2400 to 2655 K, the oxygen partial pressure dependency of x in ThO 2 -x was found to be approximately proportional to PO 2 - 1 /4to PO 2 - 1 /. The small extent of reduction over a wide range of oxygen potentials at these temperatures is a clear illustration of the higher stability of the ThO 2 -x phase compared with that of UO 2 -x. Values of ΔHO 2 and ΔSO 2 have been estimated for selected compositions from the dependence of the measured oxygen potential on temperature. Estimates of the standard free energy of formation of bivariant ThO 2 -x compositions have been made. A substantial increase in the total pressure of thorium-bearing species occurs when stoichiometric thoria is reduced toward the lower phase boundary. (orig.) [de

High-resolution spectra of stars in globular clusters. VI - Oxygen-deficient red giant stars in M13

International Nuclear Information System (INIS)

Brown, J.A.; Wallerstein, G.; Oke, J.B.

1991-01-01

From high-resolution, high signal-to-noise spectra, abundances of carbon, nitrogen, and oxygen and the C-12/C-13 ratio for five red giants in M13, including star II-67, which has previously been reported to be deficient in oxygen have been determined. Three of the five stars exhibit substantial oxygen deficiencies; O/Fe values range from +0.5 to less than about 0.3. The sum of the CNO nuclides is the same for all stars, which is interpreted as evidence that mixing of CNO-cycled material into the envelope is the cause of the variations in oxygen abundance. 41 refs

Oxygen-deficient hematite nanorods as high-performance and novel negative electrodes for flexible asymmetric supercapacitors.

Science.gov (United States)

Lu, Xihong; Zeng, Yinxiang; Yu, Minghao; Zhai, Teng; Liang, Chaolun; Xie, Shilei; Balogun, Muhammad-Sadeeq; Tong, Yexiang

2014-05-21

Oxygen-deficient α-Fe2 O3 nanorods with outstanding capacitive performance are developed and demonstrated as novel negative electrodes for flexible asymmetric supercapacitors. The asymmetric-supercapacitor device based on the oxygen-deficient α-Fe2 O3 nanorod negative electrode and a MnO2 positive electrode achieves a maximum energy density of 0.41 mW·h/cm(3) ; it is also capable of charging a mobile phone and powering a light-emitting diode indicator. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ethanol flame synthesis of carbon nanotubes in deficient oxygen environments

Science.gov (United States)

Hu, Wei-Chieh; Lin, Ta-Hui

2016-04-01

In this study, carbon nanotubes (CNTs) were synthesized using ethanol diffusion flames in a stagnation-flow system composed of an upper oxidizer duct and a lower liquid pool. In the experiments, a gaseous mixture of oxygen and nitrogen flowed from the upper oxidizer duct, and then impinged onto the vertically aligned ethanol pool to generate a planar and steady diffusion flame in a deficient oxygen environment. A nascent nickel mesh was used as the catalytic metal substrate to collect deposited materials. The effect of low oxygen concentration on the formation of CNTs was explored. The oxygen concentration significantly influenced the flame environment and thus the synthesized carbon products. Lowering the oxygen concentration increased the yield, diameter, and uniformity of CNTs. The optimal operating conditions for CNT synthesis were an oxygen concentration in the range of 15%-19%, a flame temperature in the range of 460 °C-870 °C, and a sampling position of 0.5-1 mm below the upper edge of the blue flame front. It is noteworthy that the concentration gradient of C2 species and CO governed the CNT growth directly. CNTs were successfully fabricated in regions with uniform C2 species and CO distributions.

Synthesis of surface oxygen-deficient BiPO{sub 4} nanocubes with enhanced visible light induced photocatalytic activity

Energy Technology Data Exchange (ETDEWEB)

Shi, Bingtao; Yin, Haoyong; Li, Tao; Gong, Jianying; Lv, Shumei; Nie, Qiulin, E-mail: yhy@hdu.edu.cn [College of Materials & Environmental Engineering, Hangzhou Dianzi University, Hangzhou (China)

2017-05-15

The visible light driven BiPO{sub 4} nanocubes with sufficient surface oxygen deficiency were fabricated by a hydrothermal process and subsequently ultrasonic assistant Fe reduction process. The products were characterized by XRD, DRS, XPS, SEM and TEM which showed that the BiPO{sub 4} had cuboid-like shape with a smooth surface and clear edges and the oxygen vacancies were successfully introduced on the surface of the BiPO{sub 4} nanocubes. The as prepared oxygen-deficient BiPO{sub 4} nanocubes showed greatly enhanced visible light induced photocatalytic activity in degradation of Rhodamine B. The enhanced photocatalytic performance and expanded visible light response of BiPO{sub 4} may be due to the introduction of surface oxygen vacancies which can generate the oxygen vacancies mid-gap states lower to the conduction band of BiPO{sub 4}. (author)

A study on oxygen-deficient YBa2Cu3O7-δ superconductors by positron lifetime spectroscopy

International Nuclear Information System (INIS)

Zhang Jincang; Liu Fengqi; Liu Junzheng; Cao Shixun; Cheng Guosheng

1995-01-01

Positron lifetime spectroscopy has been used for studying various oxygen-deficient YBa 2 Cu 3 O 7 - δ (δ = 0.06-0.68) at normal state (300 K) and Superconducting state (77 K). Using the two-state trapping model, the experimental results were analysed and there exists a typical positron annihilation characteristics in this systems. The local electron density n e and vacancy concentration C v are calculated as a function of oxygen-deficiency δ. The mechanism of positron annihilation and the correlation with superconductivity are also discussed

Molecular diversity of fungi from marine oxygen-deficient environments (ODEs)

Digital Repository Service at National Institute of Oceanography (India)

Manohar, C.S.; Forster, D.; Kauff, F.; Stoeck, T.

. Sparrow Jr F K (1936) Biological observations of the marine fungi of woods hole waters. Biol Bull 70: 236-263. States JS & Christensen M (2001) Fungi Associated with Biological Soil Crusts in Desert Grasslands of Utah and Wyoming. Mycologia 93: 432... version: Biology of marine fungi. Ed. by: Raghukumar, C. (Prog. Mol. Subcellular Biol). Springer, vol.53 (Chap 10); 2012; 189-208 Chapter # 10 Molecular diversity of fungi from marine oxygen-deficient environments (ODEs) Cathrine S. Jebaraj 1...

Lack of oxygen effect in glutathione-deficient human cells in culture

International Nuclear Information System (INIS)

Edgren, M.; Larsson, A.; Nilsson, K.; Revesz, L.; Scott, O.C.A.

1980-01-01

The frequency of X-ray-induced DNA breaks was determined in human cell lines which are deficient in glutathione synthetase and have a greatly reduced glutathione content. Hydroxyapatite chromatography was used for the estimation of the DNA breaks in cell cultures, which were derived either from lymphoblasts transformed by infection with EB virus or from fibroblasts. The dose-effect relationship for the induction of breaks when radiation exposure was made in argon, was similar to that found when exposure was made in air. In control cultures with normal glutathione content, the induction of breaks was enhanced when irradiation was made under aerobic, instead of anaerobic, conditions. Treatment of the glutathione-deficient cells with the hypoxic radiosensitizer misonidazole did not enhance the induction of breaks by radiation delivered either in air or in argon. In control cultures, radiation induction of breaks was enhanced by misonidazole under anaerobic but not under aerobic conditions. When the glutathione-deficient cells were pretreated with cysteamine however, irradiation in the absence of oxygen resulted in a decreased frequency of DNA breaks. (author)

Ordered oxygen deficient '112'perovskites, LnBaCo2 O5⋅ 50 ...

Indian Academy of Sciences (India)

... Refresher Courses · Symposia · Live Streaming. Home; Journals; Bulletin of Materials Science; Volume 32; Issue 3. Ordered oxygen deficient '112' perovskites, LnBaCo2O5.50+: complex magnetism and transport properties. B Raveau Md Motin Seikh V Pralong V Caignaert. Volume 32 Issue 3 June 2009 pp 305-312 ...

Thermal expansion behaviour in the oxygen deficient perovskites Sr2BSbO5.5 (B=Ca, Sr, Ba). Competing effects of water and oxygen ordering

International Nuclear Information System (INIS)

Zhou Qingdi; Kennedy, Brendan J.; Avdeev, Maxim

2011-01-01

Neutron diffractions studies reveal the presence of oxygen disorder in the oxygen deficient perovskites Sr 2 BSbO 5.5 (B=Ca, Sr, Ba). Synchrotron X-ray studies demonstrate that these oxides have a double perovskite-type structure with the cell size increasing as the size of the B cation increases from 8.2114(2) A for B=Ca to 8.4408(1) A for B=Ba. It is postulated that a combination of local clustering of the anions and vacancies together with water-water and water-host hydrogen bonds plays a role in defining the volume of the encapsulated water clusters and that changes in the local structure upon heating result in anomalous thermal expansion observed in variable temperature diffraction measurements. - Graphical abstract: The oxides Sr 2 BSbO 5.5 (B=Ca, Sr, Ba) have unusual anion disorder. There is a lag in the contraction in the cell size of Sr 2 CaSbO 5.5 nH 2 O established from X-ray diffraction measurements following the loss of water suggesting changes on the local structure are important. Highlights: → The average structures of the defect perovskites Sr 2 MSbO 5.5 established. → Anion and cation disorder quantified by neutron and synchrotron X-ray diffraction. → Anomalous thermal expansion due to local clustering of anions and vacancies observed.

Selective identification of specialized pro-resolving lipid mediators from their biosynthetic double di-oxygenation isomers.

Science.gov (United States)

Hansen, Trond V; Dalli, Jesmond; Serhan, Charles N

The n-3 polyunsaturated fatty acids are substrates for lipoxygenases and cyclooxygenases. During inflammatory processes, these enzymes form several distinct families of oxygenated polyunsaturated fatty acids coined specialized pro-resolving lipid mediators. Structural elucidation of these natural products using LC-MS/MS based metabololipidomics with the pico- to nanogram amounts of biosynthetic material available have been performed. The specialized pro-resolving lipid mediators display stereospecific and potent anti-inflammatory and pro-resolving actions. Most often the different families among these mediators are chemically characterized by two or three chiral, secondary alcohols, separated by either an E,E,Z -triene or an E,Z,E,E -tetraenemoiety. The lipoxygenases also form other oxygenated polyunsaturated natural products, coined double di-oxygenation products, that are constitutional isomers of the protectin and maresin families of specialized pro-resolving lipid mediators. Very often these products exhibit similar chromatographic properties and mass spectrometrical fragment ions as the pro-resolving mediators. In addition, the double di-oxygenation products are sometimes formed in larger amounts than the specialized pro-resolving lipid mediators. Thus, it is not always possible to distinguish between the specialized pro-resolving mediators and their double di-oxygenation isomers in biological systems, using LC/MS-based techniques. Herein, a convenient and easy-to-use protocol to meet this challenge is presented.

Persistent optically induced magnetism in oxygen-deficient strontium titanate.

Science.gov (United States)

Rice, W D; Ambwani, P; Bombeck, M; Thompson, J D; Haugstad, G; Leighton, C; Crooker, S A

2014-05-01

Strontium titanate (SrTiO3) is a foundational material in the emerging field of complex oxide electronics. Although its bulk electronic and optical properties are rich and have been studied for decades, SrTiO3 has recently become a renewed focus of materials research catalysed in part by the discovery of superconductivity and magnetism at interfaces between SrTiO3 and other non-magnetic oxides. Here we illustrate a new aspect to the phenomenology of magnetism in SrTiO3 by reporting the observation of an optically induced and persistent magnetization in slightly oxygen-deficient bulk SrTiO3-δ crystals using magnetic circular dichroism (MCD) spectroscopy and SQUID magnetometry. This zero-field magnetization appears below ~18 K, persists for hours below 10 K, and is tunable by means of the polarization and wavelength of sub-bandgap (400-500 nm) light. These effects occur only in crystals containing oxygen vacancies, revealing a detailed interplay between magnetism, lattice defects, and light in an archetypal complex oxide material.

Study on the effects of fluorine and oxygen deficiency on YBa2Cu3O7 by ab initio method

Institute of Scientific and Technical Information of China (English)

刘洪霖; 曹晓卫; 瞿丽曼; 陈念贻

1997-01-01

The calculations of clusters modeling the fluorine-doping and oxygen deficiency of YBa2Cu3O2,have been performed by the method of all-electron ab initio Hartree-Fock with self-consistent crystal field Results show that in CuO planes electric charge significantly increases,the chemical valence of Cu decreases and the covalent bonding of Cu-O greatly weakens owing to oxygen deficiency,while the effect of F restores the local electronic structure of YBa2Cu3O7 The reported opinion that F occupied the oxygen vacancy in Cu-O chains seems disputable according to the calculated bonding characteristics.

Positron-annihilation study of oxygen-deficient YBa2Cu3Ox (6.3

International Nuclear Information System (INIS)

Tang, C.Q.; Li, B.R.; Chen, A.

1990-01-01

We have measured the positron-lifetime spectra of oxygen-deficient YBa 2 Cu 3 O x for 6.3 m , τ 1 , τ 2 , and I 2 have a significant oxygen-content dependence. It is suggested that there are many kinds of positron states in polycrystalline YBa 2 Cu 3 O x , the disordering of O(1) vacancies strongly affects positron lifetime, and with gradually decreasing x the average electronic density decreases and the configuration and/or the charge states of the oxygen vacancies change in the region containing Cu(1)-O(1) chains

Oxygen pumping characteristics of Cu-Ti double substituted bismuth vanadate

Energy Technology Data Exchange (ETDEWEB)

Paydar, M.H. [Shiraz Univ. (Iran). Dept. of Metallurgy and Material Sciences; Hadian, A.M. [Teheran Univ. (Iran). Dept. of Metallurgy and Material Sciences; Fafilek, G. [Technische Univ., Vienna (Austria). Inst. fuer Technische Elektrochemie

2002-07-01

In the present paper, we are going to report on a detailed study of the characteristics of an electrochemical oxygen pump for an open system using Cu-Ti double substituted bismuth vanadate as the electrolyte. The major objectives are to show a correlation between oxygen pumping current, cell voltage, Faradic efficiency and oxygen production rate. The maximum current density that can be applied without significant structural modification has been determined and the effect of working temperature on the mentioned parameters have been investigated. The results show that there is an Ohmic relationship between current and voltage at low current densities and a deviation towards lower voltages than expected from Ohm's law with increasing current density. The oxygen production rate increased in a linear fashion by increasing the current density while at high current densities, corresponding to the non linear current voltage section, its gradient decline. Under constant current load, at very high current density (I > 800 mAcm{sup -2}), instability in cell potential was observed, which was reversible and supposed to be the effect of electronic percolation. (orig.)

Charge doping and large lattice expansion in oxygen-deficient heteroepitaxial WO3

Science.gov (United States)

Mattoni, Giordano; Filippetti, Alessio; Manca, Nicola; Zubko, Pavlo; Caviglia, Andrea D.

2018-05-01

Tungsten trioxide (WO3) is a versatile material with widespread applications ranging from electrochromics and optoelectronics to water splitting and catalysis of chemical reactions. For technological applications, thin films of WO3 are particularly appealing, taking advantage from a high surface-to-volume ratio and tunable physical properties. However, the growth of stoichiometric crystalline thin films is challenging because the deposition conditions are very sensitive to the formation of oxygen vacancies. In this paper, we show how background oxygen pressure during pulsed laser deposition can be used to tune the structural and electronic properties of WO3 thin films. By performing x-ray diffraction and low-temperature electrical transport measurements, we find changes in the WO3 lattice volume of up to 10% concomitantly with a resistivity drop of more than five orders of magnitude at room temperature as a function of increased oxygen deficiency. We use advanced ab initio calculations to describe in detail the properties of the oxygen vacancy defect states and their evolution in terms of excess charge concentration. Our results depict an intriguing scenario where structural, electronic, optical, and transport properties of WO3 single-crystal thin films can all be purposely tuned by controlling the oxygen vacancy formation during growth.

Accumulation of Fe oxyhydroxides in the Peruvian oxygen deficient zone implies non-oxygen dependent Fe oxidation

Science.gov (United States)

Heller, Maija I.; Lam, Phoebe J.; Moffett, James W.; Till, Claire P.; Lee, Jong-Mi; Toner, Brandy M.; Marcus, Matthew A.

2017-08-01

Oxygen minimum zones (OMZs) have been proposed to be an important source of dissolved iron (Fe) into the interior ocean. However, previous studies in OMZs have shown a sharp decrease in total dissolved Fe (dFe) and/or dissolved Fe(II) (dFe(II)) concentrations at the shelf-break, despite constant temperature, salinity and continued lack of oxygen across the shelf-break. The loss of both total dFe and dFe(II) suggests a conversion of the dFe to particulate form, but studies that have coupled the reduction-oxidation (redox) speciation of both dissolved and particulate phases have not previously been done. Here we have measured the redox speciation and concentrations of both dissolved and particulate forms of Fe in samples collected during the U.S. GEOTRACES Eastern tropical Pacific Zonal Transect (EPZT) cruise in 2013 (GP16). This complete data set allows us to assess possible mechanisms for loss of dFe. We observed an offshore loss of dFe(II) within the oxygen deficient zone (ODZ), where dissolved oxygen is undetectable, accompanied by an increase in total particulate Fe (pFe). Total pFe concentrations were highest in the upper ODZ. X-ray absorption spectroscopy revealed that the pFe maximum was primarily in the Fe(III) form as Fe(III) oxyhydroxides. The remarkable similarity in the distributions of total particulate iron and nitrite suggests a role for nitrite in the oxidation of dFe(II) to pFe(III). We present a conceptual model for the rapid redox cycling of Fe that occurs in ODZs, despite the absence of oxygen.

Human cathepsin L rescues the neurodegeneration and lethality incathepsin B/L double deficient mice

Energy Technology Data Exchange (ETDEWEB)

Sevenich, Lisa; Pennacchio, Len A.; Peters, Christoph; Reinheckel, Thomas

2006-01-09

Cathepsin B (CTSB) and cathepsin L (CTSL) are two widelyexpressed cysteine proteases thought to predominantly reside withinlysosomes. Functional analysis of CTSL in humans is complicated by theexistence of two CTSL-like homologues (CTSL and CTSL2), in contrast tomice which contain only one CTSL enzyme. Thus transgenic expression ofhuman CTSL in CTSL deficient mice provides an opportunity to study the invivo functions of this human protease without interference by its highlyrelated homologue. While mice with single gene deficiencies for murineCTSB or CTSL survive without apparent neuromuscular impairment, murineCTSB/CTSL double deficient mice display degeneration of cerebellarPurkinje cells and neurons of the cerebral cortex, resulting in severehypotrophy, motility defects, and lethality during their third to fourthweek of life. Here we show that expression of human CTSL through agenomic transgene results in widespread expression of human CTSL in themouse which is capable of rescuing the lethality found in CTSB/CTSLdouble-deficient animals. Human CTSL is expressed in the brain of thesecompound mutants predominantly in neurons of the cerebral cortex and inPurkinje cells of the cerebellum, where it appears to prevent neuronalcell death.

Enhanced metabolic versatility of planktonic sulfur-oxidizing γ-proteobacteria in an oxygen-deficient coastal ecosystem

Directory of Open Access Journals (Sweden)

Alejandro A. Murillo

2014-07-01

Full Text Available Sulfur-oxidizing Gamma-proteobacteria are abundant in marine oxygen-deficient waters, and appear to play a key role in a previously unrecognized cryptic sulfur cycle. Metagenomic analyses of members of the uncultured SUP05 lineage in the Canadian seasonally anoxic fjord Saanich Inlet (SI, hydrothermal plumes in the Guaymas Basin (GB and single cell genomics analysis of two ARCTIC96BD-19 representatives from the South Atlantic Sub-Tropical Gyre (SASG have shown them to be metabolically versatile. However, SI and GB SUP05 bacteria seem to be obligate chemolithoautotrophs, whereas ARCTIC96BD-19 has the genetic potential for aerobic respiration. Here, we present results of a metagenomic analysis of sulfur-oxidizing Gamma-proteobacteria (GSO, closely related to the SUP05/ARCTIC96BD-19 clade, from a coastal ecosystem in the eastern South Pacific (ESP. This ecosystem experiences seasonal anoxia and accumulation of nitrite and ammonium at depth, with a corresponding increase in the abundance of GSO representatives. The ESP-GSOs appear to have a significantly different gene complement than those from Saanich Inlet, Guaymas Basin and SASG. Genomic analyses of de novo assembled contigs indicate the presence of a complete aerobic respiratory complex based on the cytochrome bc1 oxidase. Furthermore, they appear to encode a complete TCA cycle and several transporters for dissolved organic carbon species, suggesting a mixotrophic lifestyle. Thus, the success of sulfur-oxidizing Gamma-proteobacteria in oxygen-deficient marine ecosystems appears due not only to their previously recognized anaerobic metabolic versatility, but also to their capacity to function under aerobic conditions using different carbon sources. Finally, members of ESP-GSO cluster also have the genetic potential for reducing nitrate to ammonium based on the nirBD genes, and may therefore facilitate a tighter coupling of the nitrogen and sulfur cycles in oxygen-deficient waters.

Electrical features of an amorphous indium-gallium-zinc-oxide film transistor using a double active matrix with different oxygen contents

International Nuclear Information System (INIS)

Koo, Ja Hyun; Kang, Tae Sung; Hong, Jin Pyo

2012-01-01

The electrical characteristics of amorphous indium-gallium-zinc-oxide (a-IGZO) thin film transistor (TFTs) are systematically studied using a double a-IGZO active layer that is composed of a-IGZO x (oxygen-ion-poor region) and a-IGZO y (oxygen-ion-rich-region). An active layer is designed to have a serially-stacked bi-layer matrix with different oxygen contents, providing the formation of different electron conduction channels. Two different oxygen contents in the active layer are obtained by varying the O 2 partial pressure during sputtering. The a-IGZO TFT based on a double active layer exhibits a high mobility of 9.1 cm 2 /Vsec, a threshold voltage (V T ) of 16.5 V, and ΔV T shifts of less than 1.5 V under gate voltage stress. A possible electrical sketch for the double active layer channel is also discussed.

Porous layered double hydroxides synthesized using oxygen generated by decomposition of hydrogen peroxide

NARCIS (Netherlands)

Gonzalez Rodriguez, P.; de Ruiter, M.P.; Wijnands, Tom; ten Elshof, Johan E.

2017-01-01

Porous magnesium-aluminium layered double hydroxides (LDH) were prepared through intercalation and decomposition of hydrogen peroxide (H2O2). This process generates oxygen gas nano-bubbles that pierce holes in the layered structure of the material by local pressure build-up. The decomposition of the

γ-ray dose rate effect in DNA double-strand break repair deficient murine cells

International Nuclear Information System (INIS)

Li Liya; Li Peiwen

2002-01-01

Objective: To analyze the dose rate effect and potentially lethal damage repair in DNA double-strand break repair deficient murine cells (SCID) irradiated by γ-ray. Methods: The wild type (CB.17+/+) and SCID cells were exposed to γ-ray at high and low dose rates. The high dose rate exposure was fractionated into two equal doses at 24 h intervals. The survival rates of irradiated cells were calculated by clone-forming analysis. Results: When γ-ray was given to wild type (CB.17+/+) cells in two fractions at 24 h intervals, the survival rate was significantly higher than that when the same total dose was given singly. In contrast, there was no difference in the survival rates between the single and fractionated exposure in SCID cells. SCID cells were more sensitive than CB.17+/+ cells to both low and high dose rates γ-ray exposure for cell killing. The survival rate by low dose rate exposure was significantly higher than that by high dose rate exposure, not only in CB.17+/+ cells but also in SCID cells. Conclusions: SCID cells are deficient in repairing γ-ray induced double-strand breaks. There is dose rate effect in both SCID and CB.17+/+ cells

Aerobic Microbial Respiration In Oceanic Oxygen Minimum Zones

DEFF Research Database (Denmark)

Kalvelage, Tim; Lavik, Gaute; Jensen, Marlene Mark

2015-01-01

Oxygen minimum zones are major sites of fixed nitrogen loss in the ocean. Recent studies have highlighted the importance of anaerobic ammonium oxidation, anammox, in pelagic nitrogen removal. Sources of ammonium for the anammox reaction, however, remain controversial, as heterotrophic denitrifica......Oxygen minimum zones are major sites of fixed nitrogen loss in the ocean. Recent studies have highlighted the importance of anaerobic ammonium oxidation, anammox, in pelagic nitrogen removal. Sources of ammonium for the anammox reaction, however, remain controversial, as heterotrophic...... denitrification and alternative anaerobic pathways of organic matter remineralization cannot account for the ammonium requirements of reported anammox rates. Here, we explore the significance of microaerobic respiration as a source of ammonium during organic matter degradation in the oxygen-deficient waters off...... Namibia and Peru. Experiments with additions of double-labelled oxygen revealed high aerobic activity in the upper OMZs, likely controlled by surface organic matter export. Consistently observed oxygen consumption in samples retrieved throughout the lower OMZs hints at efficient exploitation of vertically...

Embryonic Lethality Due to Arrested Cardiac Development in Psip1/Hdgfrp2 Double-Deficient Mice.

Directory of Open Access Journals (Sweden)

Hao Wang

Full Text Available Hepatoma-derived growth factor (HDGF related protein 2 (HRP2 and lens epithelium-derived growth factor (LEDGF/p75 are closely related members of the HRP2 protein family. LEDGF/p75 has been implicated in numerous human pathologies including cancer, autoimmunity, and infectious disease. Knockout of the Psip1 gene, which encodes for LEDGF/p75 and the shorter LEDGF/p52 isoform, was previously shown to cause perinatal lethality in mice. The function of HRP2 was by contrast largely unknown. To learn about the role of HRP2 in development, we knocked out the Hdgfrp2 gene, which encodes for HRP2, in both normal and Psip1 knockout mice. Hdgfrp2 knockout mice developed normally and were fertile. By contrast, the double deficient mice died at approximate embryonic day (E 13.5. Histological examination revealed ventricular septal defect (VSD associated with E14.5 double knockout embryos. To investigate the underlying molecular mechanism(s, RNA recovered from ventricular tissue was subjected to RNA-sequencing on the Illumina platform. Bioinformatic analysis revealed several genes and biological pathways that were significantly deregulated by the Psip1 knockout and/or Psip1/Hdgfrp2 double knockout. Among the dozen genes known to encode for LEDGF/p75 binding factors, only the expression of Nova1, which encodes an RNA splicing factor, was significantly deregulated by the knockouts. However the expression of other RNA splicing factors, including the LEDGF/p52-interacting protein ASF/SF2, was not significantly altered, indicating that deregulation of global RNA splicing was not a driving factor in the pathology of the VSD. Tumor growth factor (Tgf β-signaling, which plays a key role in cardiac morphogenesis during development, was the only pathway significantly deregulated by the double knockout as compared to control and Psip1 knockout samples. We accordingly speculate that deregulated Tgf-β signaling was a contributing factor to the VSD and prenatal lethality

The spatial distribution of temperature and oxygen deficiency in spark-plasma sintered superconducting Bi-based materials

International Nuclear Information System (INIS)

Govea-Alcaide, E.; Pérez-Fernández, J.E.; Machado, I.F.; Jardim, R.F.

2014-01-01

Pre-reacted powders of (Bi–Pb) 2 Sr 2 Ca 2 Cu 3 O 10+δ (Bi-2223) were consolidated by using the spark plasma sintering (SPS) technique under vacuum and at different consolidate temperatures T D . X-ray diffraction patterns revealed that the dominant phase in all SPS samples is the Bi-2223 phase, but traces of the Bi 2 Sr 2 CaCu 2 O 10+x (Bi-2212) phase were identified. We have found that the transport properties of SPS samples depend on their oxygen content because the SPS process is performed under vacuum. Simulations by using the finite element method (FEM) were performed for determining the actual temperature in which powders are consolidated. From these results we have inferred that SPS samples are oxygen deficient and such a deficiency is more marked near the grain boundaries, suggesting the occurrence of grains with core–shell morphology. We also argued that the width of the shell depends on the consolidation temperature, a feature corroborated by the FEM simulations

μ+ SR study of antiferromagnetism and superconductivity in oxygen deficient YBa2Cu3Ox

International Nuclear Information System (INIS)

Brewer, J.H.; Carolan, J.; Chaklader, A.C.D.; Hardy, W.N.; Hayden, M.; Kaplan, N.; Kempton, J.; Kiefl, R.F.; Kreitzman, S.R.; Kulpa, A.; Luke, G.M.; Riseman, T.M.; Roehmer, G.; Schleger, P.; Williams, D.L.; Ansaldo, E.J.; Kossler, W.J.; Watanabe, Y.; Yamazaki, T.

1987-12-01

Positive muon spin rotation and relaxation (μ + SR) measurements of the oxygen-deficient perovskite YBa 2 Cu 3 O x have revealed local antiferromagnetic (AFM) order for 6.0 ≤ ∼ x ≤ ∼ 6.4 with a Neel temperature T N that decreases rapidly with increasing oxygen content x. For carefully annealed samples with 6.35 ≤ ∼ x ≤ ∼ 6.5 the superconducting (SC) transition temperature T C increases smoothly with x from 25 K at x=6.348 to 60 K at x=6.507. Two such samples with x = 6.348 and x = 6.400 seem to 'switch' from SC to AFM at low temperatures. (Author) (10 refs., 3 figs.)

Survival curves of irradiated glutathione-deficient human fibroblasts: indication of a reduced enhancement of radiosensitivity by oxygen and misonidazole

International Nuclear Information System (INIS)

Midander, J.; Deschavanne, P.J.; Malaise, E.P.; Revesz, L.

1982-01-01

Fibroblasts derived from a patient with 5-oxoprolinuria are genetically deficient in glutathione synthetase. This deficiency causes a dramatic decrease in intracellular glutathione (GSH) level. The radiosensitivity of GSH deficient cells (GSH) was studied in vitro using colony forming ability as an endpoint. Cells with normal GSH level, obtained from the healthy brother of the patient, were used as controls. When irradiated in 95% air-5% CO 2 , GSH - cells are slightly but significantly more radiosensitive than GSH + controls (dose modifying factor (DMF) of 1.2). When irradiated in argon, the survival curve of GSH - cells indicates an oxygen enhancement ratio (OER) of 1.5 when compared to the curve obtained in oxic conditions. The OER of control cells in the same conditions is 2.9. In comparison to results obtained in air, 100% oxygen moderately increases the radiosensitivity of GSH + cells (DMF 1,23), while it has a very low effect on GSH - cells (DMF 1.06). These results suggest that intracellular GSH plays an essential protective role in hypoxia, its effect is reduced in air and practically disappears in 100% oxygen. When cells are incubated with 8 mM misonidazole 2 hours before irradiation, the drug has a much greater sensitizing effect on GSH + cells (DMF 2.33) than on GSH - cells (DMF 1.55). The results demonstrate that intracellular GSH level plays a major role in the response of hypoxic cells, irradiated either alone or in the presence of misonidazole

Cardiomyocyte hypertrophy induced by Endonuclease G deficiency requires reactive oxygen radicals accumulation and is inhibitable by the micropeptide humanin.

Science.gov (United States)

Blasco, Natividad; Cámara, Yolanda; Núñez, Estefanía; Beà, Aida; Barés, Gisel; Forné, Carles; Ruíz-Meana, Marisol; Girón, Cristina; Barba, Ignasi; García-Arumí, Elena; García-Dorado, David; Vázquez, Jesús; Martí, Ramon; Llovera, Marta; Sanchis, Daniel

2018-06-01

The endonuclease G gene (Endog), which codes for a mitochondrial nuclease, was identified as a determinant of cardiac hypertrophy. How ENDOG controls cardiomyocyte growth is still unknown. Thus, we aimed at finding the link between ENDOG activity and cardiomyocyte growth. Endog deficiency induced reactive oxygen species (ROS) accumulation and abnormal growth in neonatal rodent cardiomyocytes, altering the AKT-GSK3β and Class-II histone deacethylases (HDAC) signal transduction pathways. These effects were blocked by ROS scavengers. Lack of ENDOG reduced mitochondrial DNA (mtDNA) replication independently of ROS accumulation. Because mtDNA encodes several subunits of the mitochondrial electron transport chain, whose activity is an important source of cellular ROS, we investigated whether Endog deficiency compromised the expression and activity of the respiratory chain complexes but found no changes in these parameters nor in ATP content. MtDNA also codes for humanin, a micropeptide with possible metabolic functions. Nanomolar concentrations of synthetic humanin restored normal ROS levels and cell size in Endog-deficient cardiomyocytes. These results support the involvement of redox signaling in the control of cardiomyocyte growth by ENDOG and suggest a pathway relating mtDNA content to the regulation of cell growth probably involving humanin, which prevents reactive oxygen radicals accumulation and hypertrophy induced by Endog deficiency. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

On the oxygen deficiency of high-Tc Y1Ba2Cu3O7-μ ceramics

International Nuclear Information System (INIS)

Szasz, A.; Dankhazi, Z.; Kojnok, J.; Trager, T.; Matrai, J.; Gyorgy, I.; Kirchmayr, H.; Mueller, H.; Watson, L.M.

1991-01-01

The role of oxygen deficiency in Y 1 Ba 2 Cu 3 O 7-μ ceramics was investigated by differential thermal analysis (DTA), differential thermogravimetry (DTG), linear thermal expansion (LTE), and by soft x-ray fluorescence spectroscopy (SXFS). The interdependence of the measured parameters and some of the stability criteria are discussed

Oxygen enhancement ratios for glutathione-deficient human fibroblasts determined from the frequency of radiation induced micronuclei

International Nuclear Information System (INIS)

Midander, J.

1982-01-01

The yield of micronuclei (MN) was determined to study the radiosensitizing effect of oxygen on three human fibroblast strains, characterized by genetically defined differences in their glutathione (GSH) level. Cells were irradiated in paired experiments with x-ray doses of 2.66 and 6.65 gy in their exponential growth phase in a monolayer under oxic and anoxic conditions. Results indicated a reduced oxygen effect for the GSH deficient cells, the reduction of o.e.r. being most pronounced in the case of GSHsup(-/-) cells, when it was close to unity. The o.e.r. value was intermediate for the GSHsup(+/-) in comparison with the two other cell strains. It is concluded that the data indicate a correlation between the cellular content of GSH and the oxygen enhancement of the formation of micronuclei after irradiation. (U.K.)

Evolution of Oxygen Deficiency Center on Fused Silica Surface Irradiated by Ultraviolet Laser and Posttreatment

Directory of Open Access Journals (Sweden)

Hai-Bing Lü

2014-01-01

Full Text Available Evolution of oxygen deficiency centers (ODCs on a fused silica surface irradiated using a 355 nm ultraviolet (UV laser beam in both vacuum and atmospheric conditions was quantitatively studied using photoluminescence and X-ray photoelectron spectroscopy. When the fusedsilica surface was exposed to the UV laser in vacuum, the laser damage threshold was decreased whereas the concentration of the ODCs was increased. For the fuse silica operated under the high power lasers, creation of ODCs on their surface resulted from the UV laser irradiation, and this is more severe in a high vacuum. The laser fluence and/or laser intensity have significant effects on the increase of the ODCs concentration. The ODCs can be effectively repaired using postoxygen plasma treatment and UV laser irradiation in an excessive oxygen environment. Results also demonstrated that the “gain” and “loss” of oxygen at the silica surface is a reversible and dynamic process.

(La1-xSrx)0.98MnO3 perovskite with A-site deficiencies toward oxygen reduction reaction in aluminum-air batteries

Science.gov (United States)

Xue, Yejian; Miao, He; Sun, Shanshan; Wang, Qin; Li, Shihua; Liu, Zhaoping

2017-02-01

The strontium doped Mn-based perovskites have been proposed as one of the best oxygen reduction reaction catalysts (ORRCs) to substitute the noble metal. However, few studies have investigated the catalytic activities of LSM with the A-site deficiencies. Here, the (La1-xSrx)0.98MnO3 (LSM) perovskites with A-site deficiencies are prepared by a modified solid-liquid method. The structure, morphology, valence state and oxygen adsorption behaviors of these LSM samples are characterized, and their catalytic activities toward ORR are studied by the rotating ring-disk electrode (RRDE) and aluminum-air battery technologies. The results show that the appropriate doping with Sr and introducing A-site stoichiometry can effectively tailor the Mn valence and increase the oxygen adsorption capacity of LSM. Among all the LSM samples in this work, the (La0.7Sr0.3)0.98MnO3 perovskite composited with 50% carbon (50%LSM30) exhibits the best ORR catalytic activity due to the excellent oxygen adsorption capacity. Also, this catalyst has much higher durability than that of commercial 20%Pt/C. Moreover, the maximum power density of the aluminum-air battery using 50%LSM30 as the ORRC can reach 191.3 mW cm-2. Our work indicates that the LSM/C composite catalysts with A-site deficiencies can be used as a promising ORRC in the metal-air batteries.

TrxR2 deficiencies promote chondrogenic differentiation and induce apoptosis of chondrocytes through mitochondrial reactive oxygen species

International Nuclear Information System (INIS)

Yan, Jidong; Xu, Jing; Fei, Yao; Jiang, Congshan; Zhu, Wenhua; Han, Yan; Lu, Shemin

2016-01-01

Thioredoxin reductase 2 (TrxR2) is a selenium (Se) containing protein. Se deficiency is associated with an endemic osteoarthropathy characterized by impaired cartilage formation. It is unclear whether TrxR2 have roles in cartilage function. We examined the effects of TrxR2 on chondrogenic ATDC5 cells through shRNA-mediated gene silencing of TrxR2. We demonstrated TrxR2 deficiencies could enhance chondrogenic differentiation and apoptosis of ATDC5 cells. TrxR2 deficiencies increased accumulation of cartilage glycosaminoglycans (GAGs) and mineralization. TrxR2 deficiencies also stimulated expression of extracellular (ECM) gene including Collagen II and Aggrecan. The enhanced chondrogenic properties were further confirmed by activation of Akt signaling which are required for chondrogenesis. In addition, TrxR2 deficiencies promoted chondrocyte proliferation through acceleration of cell cycle progression by increase in both S and G2/M phase cell distribution accompanied with induction of parathyroid hormone-related protein (PTHrP). Moreover, TrxR2 deficiencies induced chondrocyte death via apoptosis and increased cell sensitivity to exogenous oxidative stress. Furthermore, TrxR2 deficiencies induced emission of mitochondrial reactive oxygen species (ROS) without alteration of mitochondrial membrane potential and intracellular ATP content. Finally, treatment of TrxR2 deficiency cells with N-acetylcysteine (NAC) inhibited mitochondrial ROS production and chondrocyte apoptosis. NAC also prevented chondrogenic differentiation of TrxR2 deficiency cells by suppression of ECM gene expression, GAGs accumulation and mineralization, as well as attenuation of Akt signaling. Thus, TrxR2-mediated mitochondrial integrity is indispensable for chondrogenic differentiation of ATDC5 cells. TrxR2 deficiency-induced impaired proliferation and death of chondrocytes may be the pathological mechanism of the osteoarthropathy due to Se deficiency. Notably, this study also uncover the roles of

TrxR2 deficiencies promote chondrogenic differentiation and induce apoptosis of chondrocytes through mitochondrial reactive oxygen species

Energy Technology Data Exchange (ETDEWEB)

Yan, Jidong [Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, Shaanxi 710061 (China); Xu, Jing [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, Shaanxi 710061 (China); Fei, Yao [College of Life Sciences, Northwest University, Xi’an, Shaanxi Province 710069 (China); Jiang, Congshan; Zhu, Wenhua; Han, Yan [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, Shaanxi 710061 (China); Lu, Shemin, E-mail: lushemin@xjtu.edu.cn [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, Shaanxi 710061 (China); Key Laboratory of Environment and Genes Related to Diseases, Xi’an Jiaotong University, Ministry of Education of China (China)

2016-05-15

Thioredoxin reductase 2 (TrxR2) is a selenium (Se) containing protein. Se deficiency is associated with an endemic osteoarthropathy characterized by impaired cartilage formation. It is unclear whether TrxR2 have roles in cartilage function. We examined the effects of TrxR2 on chondrogenic ATDC5 cells through shRNA-mediated gene silencing of TrxR2. We demonstrated TrxR2 deficiencies could enhance chondrogenic differentiation and apoptosis of ATDC5 cells. TrxR2 deficiencies increased accumulation of cartilage glycosaminoglycans (GAGs) and mineralization. TrxR2 deficiencies also stimulated expression of extracellular (ECM) gene including Collagen II and Aggrecan. The enhanced chondrogenic properties were further confirmed by activation of Akt signaling which are required for chondrogenesis. In addition, TrxR2 deficiencies promoted chondrocyte proliferation through acceleration of cell cycle progression by increase in both S and G2/M phase cell distribution accompanied with induction of parathyroid hormone-related protein (PTHrP). Moreover, TrxR2 deficiencies induced chondrocyte death via apoptosis and increased cell sensitivity to exogenous oxidative stress. Furthermore, TrxR2 deficiencies induced emission of mitochondrial reactive oxygen species (ROS) without alteration of mitochondrial membrane potential and intracellular ATP content. Finally, treatment of TrxR2 deficiency cells with N-acetylcysteine (NAC) inhibited mitochondrial ROS production and chondrocyte apoptosis. NAC also prevented chondrogenic differentiation of TrxR2 deficiency cells by suppression of ECM gene expression, GAGs accumulation and mineralization, as well as attenuation of Akt signaling. Thus, TrxR2-mediated mitochondrial integrity is indispensable for chondrogenic differentiation of ATDC5 cells. TrxR2 deficiency-induced impaired proliferation and death of chondrocytes may be the pathological mechanism of the osteoarthropathy due to Se deficiency. Notably, this study also uncover the roles of

The effect of vitamin D on primary dysmenorrhea with vitamin D deficiency: a randomized double-blind controlled clinical trial.

Science.gov (United States)

Moini, Ashraf; Ebrahimi, Tabandeh; Shirzad, Nooshin; Hosseini, Reihaneh; Radfar, Mania; Bandarian, Fatemeh; Jafari-Adli, Shahrzad; Qorbani, Mostafa; Hemmatabadi, Mahboobeh

2016-06-01

Dysmenorrhea is common among women of reproductive age. This study aim was to investigate the effect of vitamin D (vit D) supplementation in treatment of primary dysmenorrhea with vit D deficiency. A randomized double-blind placebo-controlled clinical trial was conducted on 60 women with primary dysmenorrhea and vit D deficiency referred to our clinic at Arash Women's Hospital from September 2013 to December 2014. Eligible women were randomly assigned into treatment and control groups (30 in each group). Individuals in the treatment group received 50 000 IU oral vit D and the control group received placebo weekly for eight weeks. After two months of treatment, there was a significant difference in serum vit D concentration between the two groups (p dysmenorrhea and vit D deficiency could improve pain intensity.

Selective oxidation of n-butane to maleic anhydride under oxygen-deficient conditions over V-P-O mixed oxides

NARCIS (Netherlands)

Bosch, H.; Bruggink, A.A.; Ross, J.R.H.

1987-01-01

The selective oxidation of n-butane to maleic anhydride over V-P-O mixed oxides was studied under oxygen deficient conditions. The mixed oxides were prepared with P/V atomic ratios ranging from 0.7 to 1.0. Catalysts with P/V <1.0 did not show any selectivity to maleic anhydride formation, regardless

μSR in oxygen deficient YBa2Cu3Ox (6.5≤x≤7.0)

International Nuclear Information System (INIS)

Puempin, B.; Keller, H.; Kuendig, W.; Savic, I.M.; Schneider, J.W.; Simmler, H.; Zimmermann, P.; Kaldis, E.; Rusiecki, S.; Rossel, C.

1991-01-01

A systematic μSR study of the local magnetic field distribution in a series of oxygen deficient YBa 2 Cu 3 O x samples with 6.5≤x≤7.0 is reported. Special attention was given to perform the experiments under the same conditions, so that the oxygen content of the measured samples was the only parameter varied. The behavior of the depolarization rate σ as a function of the oxygen content x was found to have strong similarities with the behavior of the critical temperature Tc as a function of x. In particular, two step-like increases of σ were observed above x=6.7 and 6.9. The temperature dependence of the normalized depolarization rate σ(T)/σ(0) is well described by the two-fluid model for x≥6.781(1) and clearly deviates from this behavior for x≤6.704(1). Our results are compared to those obtained by other groups. (orig.)

Mechanical control of magnetism in oxygen deficient perovskite SrTiO3.

Science.gov (United States)

Zhang, Yajun; Wang, Jie; Sahoo, M P K; Shimada, Takahiro; Kitamura, Takayuki

2015-10-28

Mechanical control of magnetism in perovskite oxides is an important and promising approach in spintronics. Based on the first-principles calculations, we demonstrate that a negative pressure leads to a great enhancement of magnetic moment in deficient SrTiO3 with oxygen vacancies, whereas a positive pressure results in the gradual disappearance of magnetism. Spin charge density, Bader charge analysis and electronic density of states successfully elucidate the origin and underlying physics of the enhancement and disappearance of magnetism. It is found that the split electronic states of dz(2), dyz and dzx in the 3d orbitals of Ti atoms remarkably contribute to the occupancy of majority spin states under negative pressure, which induces a large magnetic moment. Under positive pressure, however, the equal occupancy of both majority and minority t2g and eg states leads to the disappearance of magnetization. In addition, both negative and positive pressures can largely lower the vacancy formation enthalpy, suggesting that the oxygen vacancy is preferable with pressure. Our findings may provide a mechanism to achieve the pressure control of magnetization in nonmagnetic perovskite oxides.

Irradiation of cells by single and double pulses of high intensity radiation: oxygen sensitization and diffusion kinetics

International Nuclear Information System (INIS)

Epp, E.R.; Ling, C.C.; Weiss, H.

1976-01-01

This paper discusses advances made on both experimental and theoretical approaches involving single and double pulses of high intensity ionizing radiation delivered to cultured bacterial and mammalian cells where the effect of oxygen is concerned. Information gained on the lifetime of oxygen-sensitive species suspected to be produced in critical molecules in irradiated cells and perhaps intimately related to the still unknown mechanisms of oxygen sensitization is described. The diffusion characteristics of oxygen at the cellular level obtained from experimental data are discussed. Current knowledge on intracellular radiolytic oxygen depletion is also presented. Future work on the use of high intensity pulsed radiation as a tool in cellular radiobiological research is outlined. It is expected that obtaining knowledge of the time available for damaged molecules to enter into chemical reactions may lead to insights into the mechanisms of radiation injury in cells, such as those involved in the oxygen effect. (Auth.)

Iron deficiency in childhood

NARCIS (Netherlands)

Uijterschout, L.

2015-01-01

Iron deficiency (ID) is the most common micronutrient deficiency in the world. Iron is involved in oxygen transport, energy metabolism, immune response, and plays an important role in brain development. In infancy, ID is associated with adverse effects on cognitive, motor, and behavioral development

Artificial oxygen transport protein

Science.gov (United States)

Dutton, P. Leslie

2014-09-30

This invention provides heme-containing peptides capable of binding molecular oxygen at room temperature. These compounds may be useful in the absorption of molecular oxygen from molecular oxygen-containing atmospheres. Also included in the invention are methods for treating an oxygen transport deficiency in a mammal.

Investigation of the relevant kinetic processes in the initial stage of a double-arcing instability in oxygen plasmas

Science.gov (United States)

Mancinelli, B.; Prevosto, L.; Chamorro, J. C.; Minotti, F. O.; Kelly, H.

2018-05-01

A numerical investigation of the kinetic processes in the initial (nanosecond range) stage of the double-arcing instability was developed. The plasma-sheath boundary region of an oxygen-operated cutting torch was considered. The energy balance and chemistry processes in the discharge were described. It is shown that the double-arcing instability is a sudden transition from a diffuse (glow-like) discharge to a constricted (arc-like) discharge in the plasma-sheath boundary region arising from a field-emission instability. A critical electric field value of ˜107 V/m was found at the cathodic part of the nozzle wall under the conditions considered. The field-emission instability drives in turn a fast electronic-to-translational energy relaxation mechanism, giving rise to a very fast gas heating rate of at least ˜109 K/s, mainly due to reactions of preliminary dissociation of oxygen molecules via the highly excited electronic state O2(B3Σu-) populated by electron impact. It is expected that this fast oxygen heating rate further stimulates the discharge contraction through the thermal instability mechanism.

Differences in heavy-ion-induced DNA double-strand breaks in a mouse DNA repair-deficient mutant cell line (SL3-147) before and after chromatin proteolysis

International Nuclear Information System (INIS)

Murakami, Masahiro; Eguchi-Kasai, Kiyomi; Sato, Koki; Minohara, Shinichi; Kanai, Tatsuaki; Yatagai, Fumio.

1995-01-01

DNA double-strand breaks induced by X- or neon beam-irradiation in a DNA double-strand break-repair-deficient mutant cell line (SL3-147) were examined. The increase in the number of DNA double-strand breaks was dose-depend after irradiation with X-rays and neon beams and was enhanced by chromatin-proteolysis treatment before irradiation. These results suggest that the induction of DNA double-strand breaks by ionizing radiation, including heavy-ions, is influenced by the chromatin structure. (author)

Intracellular nitrate in sediments of an oxygen-deficient marine basin is linked to pelagic diatoms

DEFF Research Database (Denmark)

Kamp, Anja; Petro, Caitlin; Røy, Hans

2018-01-01

Intracellular nitrate is an important electron acceptor in oxygen-deficient aquatic environments, either for the nitrate-storing microbes themselves, or for ambient microbial communities through nitrate leakage. This study links the spatial distribution of intracellular nitrate with the abundance...... and identity of nitrate-storing microbes in sediments of the Bornholm Basin, an environmental showcase for severe hypoxia. Intracellular nitrate (up to 270 nmol cm−3 sediment) was detected at all 18 stations along a 35-km transect through the basin and typically extended as deep as 1.6 cm into the sediment...

Combined effect of oxygen deficient point defects and Ni doping in radio frequency magnetron sputtering deposited ZnO thin films

Energy Technology Data Exchange (ETDEWEB)

Saha, B., E-mail: biswajit.physics@gmail.com [Thin Film and Nano Science Laboratory, Department of Physics, Jadavpur University, 700 032 Kolkata (India); Department of Physics, National Institute of Technology Agartala, Jirania 799046, Tripura (India); Das, N.S.; Chattopadhyay, K.K. [Thin Film and Nano Science Laboratory, Department of Physics, Jadavpur University, 700 032 Kolkata (India)

2014-07-01

Ni doped ZnO thin films with oxygen deficiency have been synthesized on glass substrates by radio frequency magnetron sputtering technique using argon plasma. The combined effect of point defects generated due to oxygen vacancies and Ni doping on the optical and electrical properties of ZnO thin films has been studied in this work. Ni doping concentrations were varied and the structural, optical and electrical properties of the films were studied as a function of doping concentrations. The films were characterized with X-ray diffractometer, UV–Vis–NIR spectrophotometer, X-ray photoelectron spectroscopy, atomic force microscopy and electrical conductivity measurements. Oxygen deficient point defects (Schottky defects) made the ZnO thin film highly conducting while incorporation of Ni dopant made it more functional regarding their electrical and optical properties. The films were found to have tunable electrical conductivity with Ni doping concentrations. - Highlights: • ZnO thin films prepared by radio frequency magnetron sputtering technique • Synthesis process was stimulated to introduce Schottky-type point defects. • Point defects and external doping of Ni made ZnO thin films more functional. • Point defect induced high electrical conductivity in ZnO thin film. • Significant shift in optical bandgap observed in ZnO with Ni doping concentrations.

Transport and magnetoresistance effect in an oxygen-deficient SrTiO3/La0.67Sr0.33MnO3 heterojunction

International Nuclear Information System (INIS)

Wang Jing; Chen Chang-Le; Yang Shi-Hai; Luo Bing-Cheng; Duan Meng-Meng; Jin Ke-Xin

2013-01-01

An oxygen-deficient SrTiO 3 /La 0.67 Sr 0.33 MnO 3 heterojunction is fabricated on an SrTiO 3 (001) substrate by a pulsed laser deposition method. The electrical characteristics of the heterojunction are studied systematically in a temperature range from 80 K to 300 K. The transport mechanism follows I ∞ exp(eV/nkT) under small forward bias, while it becomes space charge limited and follows I ∞ V m(T) with 1.49 < m < 1.99 under high bias. Such a heterojunction also exhibits magnetoresistance (MR) effect. The absolute value of negative MR monotonically increases with temperature decreasing and reaches 26.7% at 80 K under H = 0.7 T. Various factors, such as strain and oxygen deficiency play dominant roles in the characteristics. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Mouse but not human embryonic stem cells are deficient in rejoining of ionizing radiation-induced DNA double-strand breaks.

Science.gov (United States)

Bañuelos, C A; Banáth, J P; MacPhail, S H; Zhao, J; Eaves, C A; O'Connor, M D; Lansdorp, P M; Olive, P L

2008-09-01

Mouse embryonic stem (mES) cells will give rise to all of the cells of the adult mouse, but they failed to rejoin half of the DNA double-strand breaks (dsb) produced by high doses of ionizing radiation. A deficiency in DNA-PK(cs) appears to be responsible since mES cells expressed strand breaks more rapidly. Consistent with more rapid dsb rejoining, H2AX(-/-) mES cells also expressed 6 times more DNA-PK(cs) than wild-type mES cells. Similar results were obtained for ATM(-/-) mES cells. Differentiation of mES cells led to an increase in DNA-PK(cs), an increase in dsb rejoining rate, and a decrease in Ku70/80. Unlike mouse ES, human ES cells were proficient in rejoining of dsb and expressed high levels of DNA-PK(cs). These results confirm the importance of homologous recombination in the accurate repair of double-strand breaks in mES cells, they help explain the chromosome abnormalities associated with deficiencies in H2AX and ATM, and they add to the growing list of differences in the way rodent and human cells deal with DNA damage.

Ultrafast atomic layer-by-layer oxygen vacancy-exchange diffusion in double-perovskite LnBaCo2O5.5+δ thin films.

Science.gov (United States)

Bao, Shanyong; Ma, Chunrui; Chen, Garry; Xu, Xing; Enriquez, Erik; Chen, Chonglin; Zhang, Yamei; Bettis, Jerry L; Whangbo, Myung-Hwan; Dong, Chuang; Zhang, Qingyu

2014-04-22

Surface exchange and oxygen vacancy diffusion dynamics were studied in double-perovskites LnBaCo2O5.5+δ (LnBCO) single-crystalline thin films (Ln = Er, Pr; -0.5 atoms in the LnBCO thin films is taking the layer by layer oxygen-vacancy-exchange mechanism. The first principles density functional theory calculations indicate that hydrogen atoms are present in LnBCO as bound to oxygen forming O-H bonds. This unprecedented oscillation phenomenon provides the first direct experimental evidence of the layer by layer oxygen vacancy exchange diffusion mechanism.

Comparison of the oxygen enhancement ratio for γ-ray-induced double-strand breaks in the DNA of bacteriophage T7 as determined by two different methods of analysis

International Nuclear Information System (INIS)

Schans, G.P. van der; Drift, A.C.M. van der.

1975-01-01

Bacteriophage T7 was irradiated in a protecting medium under nitrogen and oxygen with 60 Co gamma rays. Double-strand breaks were measured by sucrose gradient sedimentation and by boundary sedimentation analysis. Both methods showed that the presence of oxygen during irradiation enhances the production of double-strand breaks. This is in contrast to a recent report which suggests that boundary sedimentation analysis does not show the effect of oxygen. The discrepancy must be ascribed to differences in the interpretation of the sedimentation data

BMI-1 Mediates Estrogen-Deficiency-Induced Bone Loss by Inhibiting Reactive Oxygen Species Accumulation and T Cell Activation.

Science.gov (United States)

Li, Jinbo; Wang, Qian; Yang, Renlei; Zhang, Jiaqi; Li, Xing; Zhou, Xichao; Miao, Dengshun

2017-05-01

Previous studies have shown that estrogen regulates bone homeostasis through regulatory effects on oxidative stress. However, it is unclear how estrogen deficiency triggers reactive oxygen species (ROS) accumulation. Recent studies provide evidence that the B lymphoma Mo-MLV insertion region 1 (BMI-1) plays a critical role in protection against oxidative stress and that this gene is directly regulated by estrogen via estrogen receptor (ER) at the transcriptional level. In this study, ovariectomized mice were given drinking water with/without antioxidant N-acetyl-cysteine (NAC, 1 mg/mL) supplementation, and compared with each other and with sham mice. Results showed that ovariectomy resulted in bone loss with increased osteoclast surface, increased ROS levels, T cell activation, and increased TNF and RANKL levels in serum and in CD4 T cells; NAC supplementation largely prevented these alterations. BMI-1 expression levels were dramatically downregulated in CD4 T cells from ovariectomized mice. We supplemented drinking water to BMI-1-deficient mice with/without NAC and compared them with each other and with wild-type (WT) mice. We found that BMI-1 deficiency mimicked alterations observed in ovariectomy whereas NAC supplementation reversed all alterations induced by BMI-1 deficiency. Because T cells are critical in mediating ovariectomy-induced bone loss, we further assessed whether BMI-1 overexpression in lymphocytes can protect against estrogen deficiency-induced osteoclastogenesis and bone loss by inhibiting oxidative stress, T cell activation, and RANKL production. When WT and Eμ-BMI-1 transgenic mice with BMI-1 specifically overexpressed in lymphocytes were ovariectomized and compared with each other and with WT sham mice, we found that BMI-1 overexpression in lymphocytes clearly reversed all alterations induced by ovariectomy. Results from this study indicate that estrogen deficiency downregulates BMI-1 and subsequently increases ROS, T cell activation, and

Replication fork stability confers chemoresistance in BRCA-deficient cells

DEFF Research Database (Denmark)

Chaudhuri, Arnab Ray; Callen, Elsa; Ding, Xia

2016-01-01

/4 complex protein, PTIP, protects Brca1/2-deficient cells from DNA damage and rescues the lethality of Brca2-deficient embryonic stem cells. However, PTIP deficiency does not restore homologous recombination activity at double-strand breaks. Instead, its absence inhibits the recruitment of the MRE11......Cells deficient in the Brca1 and Brca2 genes have reduced capacity to repair DNA double-strand breaks by homologous recombination and consequently are hypersensitive to DNA-damaging agents, including cisplatin and poly(ADP-ribose) polymerase (PARP) inhibitors. Here we show that loss of the MLL3...... nuclease to stalled replication forks, which in turn protects nascent DNA strands from extensive degradation. More generally, acquisition of PARP inhibitors and cisplatin resistance is associated with replication fork protection in Brca2-deficient tumour cells that do not develop Brca2 reversion mutations...

Iron-Deficiency Anemia

Medline Plus

Full Text Available ... Complications Undiagnosed or untreated iron-deficiency anemia may cause the following complications: Depression Heart problems. If you do not have enough hemoglobin-carrying red blood cells, your heart has to work harder to move oxygen-rich blood through your ...

Manganese deficiency in plants

DEFF Research Database (Denmark)

Schmidt, Sidsel Birkelund; Jensen, Poul Erik; Husted, Søren

2016-01-01

Manganese (Mn) is an essential plant micronutrient with an indispensable function as a catalyst in the oxygen-evolving complex (OEC) of photosystem II (PSII). Even so, Mn deficiency frequently occurs without visual leaf symptoms, thereby masking the distribution and dimension of the problem...... restricting crop productivity in many places of the world. Hence, timely alleviation of latent Mn deficiency is a challenge in promoting plant growth and quality. We describe here the key mechanisms of Mn deficiency in plants by focusing on the impact of Mn on PSII stability and functionality. We also address...... the mechanisms underlying the differential tolerance towards Mn deficiency observed among plant genotypes, which enable Mn-efficient plants to grow on marginal land with poor Mn availability....

The chemical composition of TS 01, the most oxygen-deficient planetary nebula. AGB nucleosynthesis in a metal-poor binary star

Science.gov (United States)

Stasińska, G.; Morisset, C.; Tovmassian, G.; Rauch, T.; Richer, M. G.; Peña, M.; Szczerba, R.; Decressin, T.; Charbonnel, C.; Yungelson, L.; Napiwotzki, R.; Simón-Díaz, S.; Jamet, L.

2010-02-01

The planetary nebula TS 01 (also called PN G 135.9+55.9 or SBS 1150+599A) with its record-holding low oxygen abundance and its double degenerate close binary core (period 3.9 h) is an exceptional object located in the Galactic halo. We have secured observational data in a complete wavelength range to pin down the abundances of half a dozen elements in the nebula. The abundances are obtained via detailed photoionization modelling which takes into account all the observational constraints (including geometry and aperture effects) using the pseudo-3D photoionization code Cloudy_3D. The spectral energy distribution of the ionizing radiation is taken from appropriate model atmospheres. Incidentally we find from the new observational constraints that both stellar components contribute to the ionization: the “cool” one provides the bulk of hydrogen ionization, while the “hot” one is responsible for the presence of the most highly charged ions, which explains why previous attempts to model the nebula experienced difficulties. The nebular abundances of C, N, O, and Ne are found to be 1/3.5, 1/4.2, 1/70, and 1/11 of the solar value respectively, with uncertainties of a factor 2. Thus the extreme O deficiency of this object is confirmed. The abundances of S and Ar are less than 1/30 of solar. The abundance of He relative to H is 0.089 ± 0.009. Standard models of stellar evolution and nucleosynthesis cannot explain the abundance pattern observed in the nebula. To obtain an extreme oxygen deficiency in a star whose progenitor has an initial mass of about 1 M⊙ requires an additional mixing process, which can be induced by stellar rotation and/or by the presence of the close companion. We have computed a stellar model with an initial mass of 1 M⊙, appropriate metallicity, and initial rotation of 100 km s-1, and find that rotation greatly improves the agreement between the predicted and observed abundances. Based on observations obtained at the Canada

The clinical presentation and genotype of protein C deficiency with double mutations of the protein C gene.

Science.gov (United States)

Inoue, Hirofumi; Terachi, Shin-Ichi; Uchiumi, Takeshi; Sato, Tetsuji; Urata, Michiyo; Ishimura, Masataka; Koga, Yui; Hotta, Taeko; Hara, Toshiro; Kang, Dongchon; Ohga, Shouichi

2017-07-01

Severe protein C (PC) deficiency is a rare heritable thrombophilia leading to thromboembolic events during the neonatal period. It remains unclear how individuals with complete PC gene (PROC) defects develop or escape neonatal stroke or purpura fulminans (PF). We studied the onset of disease and the genotype of 22 PC-deficient patients with double mutations in PROC based on our cohort (n = 12) and the previous reports (n = 10) in Japan. Twenty-two patients in 20 unrelated families had 4 homozygous and 18 compound heterozygous mutations. Sixteen newborns presented with PF (n = 11, 69%), intracranial thromboembolism and hemorrhage (n = 13, 81%), or both (n = 8, 50%), with most showing a plasma PC activity of <10%. Six others first developed overt thromboembolism when they were over 15 years of age, showing a median PC activity of 31% (range: 19-52%). Fifteen of the 22 patients (68%) had the five major mutations (G423VfsX82, V339M, R211W, M406I, and F181V) or two others (E68K and K193del) that have been reported in Japan. Three of the six late-onset cases, but none of the 16 neonatal cases, had the K193del mutation, which has been reported to be the most common variant of Chinese thrombophilia. A novel mutation of A309V was determined in a family of two patients with late onset. The genotype of double-PROC mutants might show less diversity than heterozygous mutants in terms of the timing of the onset of thrombophilia (newborn onset or late onset). © 2017 Wiley Periodicals, Inc.

MCP-1/CCR-2-double-deficiency severely impairs the migration of hematogenous inflammatory cells following transient cerebral ischemia in mice.

Science.gov (United States)

Schuette-Nuetgen, Katharina; Strecker, Jan-Kolja; Minnerup, Jens; Ringelstein, E Bernd; Schilling, Matthias

2012-02-01

Monocyte chemoattractant protein-1 (MCP-1) and its receptor CCR-2 are known to play a major role in inflammatory responses after cerebral ischemia. Mice deficient in either MCP-1 or CCR-2 have been reported to develop smaller infarct sizes and show decreased numbers of infiltrating inflammatory cells. In the present study we used green fluorescent protein (GFP) transgenic mice to investigate the effect of MCP-1/CCR-2-double deficiency on the recruitment of inflammatory cells in a model of both, mild and severe cerebral ischemia. We show that MCP-1/CCR-2-double deficiency virtually entirely abrogates the recruitment of hematogenous macrophages and significantly reduces neutrophil migration to the ischemic brain 4 and 7 days following focal cerebral ischemia. This argues for a predominant role of the MCP-1/CCR-2 axis in chemotaxis of monocytes despite a wide redundancy in the chemokine-receptor-system. Chemokine analysis revealed that even candidates known to be involved in monocyte and neutrophil recruitment like MIP-1α, CXCL-1, C5a, G-CSF and GM-CSF showed a reduced and delayed or even a lack of relevant compensatory response in MCP-1(-/-)/CCR-2(-/-)-mice. Solely, chemokine receptor 5 (CCR-5) increased early in both, but rose above wildtype levels at day 7 in MCP-1(-/-)/CCR-2(-/-)-animals, which might explain the higher number of activated microglial cells compared to control mice. Our study was, however, not powered to investigate infarct volumes. Further studies are needed to clarify whether these mechanisms of inflammatory cell recruitment might be essential for early infarct development and final infarct size and to evaluate potential therapeutic implications. Copyright © 2011 Elsevier Inc. All rights reserved.

Lycopene Deficiency in Ageing and Cardiovascular Disease

Science.gov (United States)

Petyaev, Ivan M.

2016-01-01

Lycopene is a hydrocarbon phytochemical belonging to the tetraterpene carotenoid family and is found in red fruit and vegetables. Eleven conjugated double bonds predetermine the antioxidant properties of lycopene and its ability to scavenge lipid peroxyl radicals, reactive oxygen species, and nitric oxide. Lycopene has a low bioavailability rate and appears in the blood circulation incorporated into chylomicrons and other apo-B containing lipoproteins. The recent body of evidence suggests that plasma concentration of lycopene is not only a function of intestinal absorption rate but also lycopene breakdown via enzymatic and oxidative pathways in blood and tissues. Oxidative stress and the accumulation of reactive oxygen species and nitric oxide may represent a major cause of lycopene depletion in ageing, cardiovascular disease, and type 2 diabetes mellitus. It has been shown recently that low carotenoid levels, and especially decreased serum lycopene levels, are strongly predictive of all-cause mortality and poor outcomes of cardiovascular disease. However, there is a poor statistical association between dietary and serum lycopene levels which occurs due to limited bioavailability of lycopene from dietary sources. Hence, it is very unlikely that nutritional intervention alone could be instrumental in the correction of lycopene and carotenoid deficiency. Therefore, new nutraceutical formulations of carotenoids with enhanced bioavailability are urgently needed. PMID:26881023

Mass-specific respiration of mesozooplankton and its role in the maintenance of an oxygen-deficient ecological barrier (BEDOX) in the upwelling zone off Chile upon presence of a shallow oxygen minimum zone

Science.gov (United States)

Donoso, Katty; Escribano, Ruben

2014-01-01

A shallow oxygen minimum zone (OMZ) in the coastal upwelling zone off Chile may vertically confine most zooplankton to a narrow (oxygen consumption of the mesozooplankton community obtained in Bay of Mejillones, northern Chile (23°S) in May 2010, December 2010 and August 2011. Mass-specific respiration rates were in the range of 8.2-24.5 μmol O2 mg dry mass- 1 day- 1, at an average temperature of 12 °C. Estimates of the mesozooplankton biomass in the water column indicated that its aerobic respiration may remove daily a maximum of about 20% of oxygen available at the base of the oxycline. Since previous work indicates that zooplankton aggregate near the base of the oxycline, the impact of aerobic respiration on oxygen content might be even stronger at this depth. Mesozooplankton respiration, along with community respiration by microorganisms near the base of the oxycline and a strongly stratified condition (limiting vertical flux of O2), are suggested as being critical factors causing and maintaining a persistent subsurface oxygen-deficient ecological barrier (BEDOX) in the upwelling zone. This BEDOX layer can have a major role in affecting and regulating zooplankton distribution and their dynamics in the highly productive coastal upwelling zone of the Humboldt Current System.

Magnetism, Spin Texture, and In-Gap States: Atomic Specialization at the Surface of Oxygen-Deficient SrTiO_{3}.

Science.gov (United States)

Altmeyer, Michaela; Jeschke, Harald O; Hijano-Cubelos, Oliver; Martins, Cyril; Lechermann, Frank; Koepernik, Klaus; Santander-Syro, Andrés F; Rozenberg, Marcelo J; Valentí, Roser; Gabay, Marc

2016-04-15

Motivated by recent spin- and angular-resolved photoemission (SARPES) measurements of the two-dimensional electronic states confined near the (001) surface of oxygen-deficient SrTiO_{3}, we explore their spin structure by means of ab initio density functional theory (DFT) calculations of slabs. Relativistic nonmagnetic DFT calculations display Rashba-like spin winding with a splitting of a few meV and when surface magnetism on the Ti ions is included, bands become spin-split with an energy difference ∼100  meV at the Γ point, consistent with SARPES findings. While magnetism tends to suppress the effects of the relativistic Rashba interaction, signatures of it are still clearly visible in terms of complex spin textures. Furthermore, we observe an atomic specialization phenomenon, namely, two types of electronic contributions: one is from Ti atoms neighboring the oxygen vacancies that acquire rather large magnetic moments and mostly create in-gap states; another comes from the partly polarized t_{2g} itinerant electrons of Ti atoms lying further away from the oxygen vacancy, which form the two-dimensional electron system and are responsible for the Rashba spin winding and the spin splitting at the Fermi surface.

Correlations between the Hall coefficient and the superconducting transport properties of oxygen-deficient YBa2Cu3O7-δ epitaxial thin films

International Nuclear Information System (INIS)

Jones, E.C.; Christen, D.K.; Thompson, J.R.; Feenstra, R.; Zhu, S.; Lowndes, D.H.; Phillips, J.M.; Siegal, M.P.; Budai, J.D.

1993-01-01

Strong correlations between the Hall coefficient R H , the transition temperature T c , and the critical current density J c were established in a series of epitaxial YBa 2 Cu 3 O 7-δ thin films as a function of oxygen deficiency δ. Steady increases in R H with δ suggest that deoxygenation reduces the density of states which, according to BCS theory, should lead to corresponding decreases in T c . In contrast, two well-known plateaus occurring at 90 K and 60 K were observed in T c vs δ. Others have ascribed these plateaus to either electronic phenomena or phase separations. We find that in the 90-K plateau, the critical current density J c (δ,H=0) decreases with δ and extrapolates toward zero at the edge of the plateau, while the relative-field dependence of J c (δ,H) and the flux-creep pinning energies are independent of δ. These observations suggest that the phase-separation scenario occurs on the 90-K plateau. However, electronic origins cannot be ruled out at present due to difficulties in determining the equilibrium superconducting properties of oxygen-deficient YBa 2 Cu 3 O 7-δ films

Resolution of the crystal structure of the deficient perovskite LaNiO2.5 from neutron powder diffraction data

International Nuclear Information System (INIS)

Alonso, J.A.; Martinez-Lope, M.J.

1996-01-01

The oxygen-deficient perovskite LaNiO 2.5 has been prepared by controlled reduction of LaNiO 3 with Zr metal. The XRD pattern could be indexed in a monoclinic unit-cell with dimensions a 0 xa 0 xa 0 (a 0 : lattice parameter of the ideal cubic perovskite). The indexing of the neutron powder diffraction pattern needed a doubled cell to account for the superstructure reflections originated by the oxygen vacancy ordering and the tilting of the Ni coordination polyhedra. The structure was solved and refined from the neutron powder data. The oxygen vacancies are ordered in such a way that square planar NiO 4 and NiO 6 octahedra alternate in the ab plane along the [110] direction. Both kinds of Ni polyhedra are fairly distorted and tilted in order to optimize the La-O distances, giving rise to a highly strained structure of metastable character. In fact, the compound readily takes oxygen, above 175 C in air, to give the much more stable LaNiO 3 perovskite. (orig.)

Relationship among mismatch repair deficiency, CDX2 loss, p53 and E-cadherin in colon carcinoma and suitability of using a double panel of mismatch repair proteins by immunohistochemistry.

Science.gov (United States)

Sayar, Ilyas; Akbas, Emin Murat; Isik, Arda; Gokce, Aysun; Peker, Kemal; Demirtas, Levent; Gürbüzel, Mehmet

2015-09-01

Biomarkers such as mismatch repair proteins, CDX2, p53, and E-cadherin are blamed for colon cancers, but the relationships of these biomarkers with each other and with pathological risk factors in colon carcinoma are still not clear. The aim of this study was to evaluate the association of these biomarkers with each other by using immunohistochemical staining and to compare their expression with pathological risk factors for colonic adenocarcinoma. We also aimed to study the usability of a double panel of mismatch repair proteins. One hundred and eleven cases with colonic adenocarcinoma were examined. There was a statistically significant relationship between tumor histological differentiation and perineural invasion, vascular invasion, mismatch repair deficiency, p53, CDX2, and E-cadherin (p < 0.05). PMS2 and MSH6 loss covered 100% of cases with mismatch repair deficiency. Mismatch repair deficiency was correlated with CDX2 loss and E-cadherin expression (p < 0.05). It was also observed that cases with PMS2 loss covered all the cases with CDX2 loss. In conclusion, this double panel may be used instead of a quadruple panel for detecting mismatch repair deficiency. Association of CDX2 and PMS2 in the present study is necessary to conduct further genetic and pathological studies focusing on these two markers together.

Influence of Hypoxic Interval Training and Hyperoxic Recovery on Muscle Activation and Oxygenation in Connection with Double-Poling Exercise.

Directory of Open Access Journals (Sweden)

Christoph Zinner

Full Text Available Here, we evaluated the influence of breathing oxygen at different partial pressures during recovery from exercise on performance at sea-level and a simulated altitude of 1800 m, as reflected in activation of different upper body muscles, and oxygenation of the m. triceps brachii. Ten well-trained, male endurance athletes (25.3±4.1 yrs; 179.2±4.5 cm; 74.2±3.4 kg performed four test trials, each involving three 3-min sessions on a double-poling ergometer with 3-min intervals of recovery. One trial was conducted entirely under normoxic (No and another under hypoxic conditions (Ho; FiO2 = 0.165. In the third and fourth trials, the exercise was performed in normoxia and hypoxia, respectively, with hyperoxic recovery (HOX; FiO2 = 1.00 in both cases. Arterial hemoglobin saturation was higher under the two HOX conditions than without HOX (p<0.05. Integrated muscle electrical activity was not influenced by the oxygen content (best d = 0.51. Furthermore, the only difference in tissue saturation index measured via near-infrared spectroscopy observed was between the recovery periods during the NoNo and HoHOX interventions (P<0.05, d = 0.93. In the case of HoHo the athletes' Pmean declined from the first to the third interval (P < 0.05, whereas Pmean was unaltered under the HoHOX, NoHOX and NoNo conditions. We conclude that the less pronounced decline in Pmean during 3 x 3-min double-poling sprints in normoxia and hypoxia with hyperoxic recovery is not related to changes in muscle activity or oxygenation. Moreover, we conclude that hyperoxia (FiO2 = 1.00 used in conjunction with hypoxic or normoxic work intervals may serve as an effective aid when inhaled during the subsequent recovery intervals.

Superconductivity, structure and oxygen deficiency in the Ba2YCu2WOY system

International Nuclear Information System (INIS)

Bokhimi, M.; Portilla, M.; Perez, R.; Universidad Nacional Autonoma de Mexico, Mexico City

1991-01-01

It is shown that the Ba-2YCu x WO y system with O≤x≤2 is composed of 2 phases, the first with composition Ba 2 YWO 6 with a small copper-solution replacing yttrium, it has cubic ordered perovskite structure with the space group Fm3m, the solution of the copper gives rise to a lattice contraction. The second phase corresponds to CuO, or Cu 2 O depending on sample preparation At large copper concentrations the first phase appears as small precipitates embedded in the second one. Reducing the samples at 1150 o C in H 2 gives rise to a separation of the phases, segregating the copper in the form of liquid metal. The reduction eliminates from the first phase the dissolved copper, and produces also some oxygen deficiency in the sample, both effects give origin to a lattice distortion in the ordered perovskite structure. Although the samples are black after the reduction, they are not electrical conductors. (author). 8 refs., 8 figs

Nitrous oxide/oxygen mixture for analgesia in adult cancer patients with breakthrough pain: A randomized, double-blind controlled trial.

Science.gov (United States)

Liu, Q; Gao, L-L; Dai, Y-L; Li, Y-X; Wang, Y; Bai, C-F; Mu, G-X; Chai, X-M; Han, W-J; Zhou, L-J; Zhang, Y-J; Tang, L; Liu, J; Yu, J-Q

2018-03-01

The aim of this study was to assess the efficacy of a fixed nitrous oxide/oxygen mixture for the management of breakthrough cancer pain. A double-blind, placebo-controlled, randomized clinical trial was undertaken in the Medical ward of Tumor Hospital of General Hospital of Ningxia Medical University. 240 cancer patients with breakthrough pain were recruited and randomly received a standard pain treatment (morphine sulphate immediate release) plus a pre-prepared nitrous oxide/oxygen mixture, or the standard pain treatment plus oxygen. The primary endpoint measure was the numerical rating scale (NRS) score measured at baseline, 5 and 15 min after the beginning of treatment, and at 5 min post treatment. In all, analysis of pain score (NRS) at 5 min after the beginning of treatment shown a significant decrease in nitrous oxide/oxygen mixture treated patients with 2.8 ± 1.3 versus 5.5 ± 1.2 in controls (p nitrous oxide/oxygen was 2.0 ± 1.1 compared with 5.6 ± 1.3 for oxygen (p nitrous oxide/oxygen mixture was effective in reducing moderate to severe breakthrough pain among patients with cancer. The management of breakthrough cancer pain is always a challenge due to its temporal characteristics of rapid onset, moderate to severe in intensity, short duration (median 30-60 min). Our study find that self-administered nitrous oxide/oxygen mixture was effective in reducing moderate to severe breakthrough cancer pain. © 2017 European Pain Federation - EFIC®.

Absence of Wip1 partially rescues Atm deficiency phenotypes in mice

Science.gov (United States)

Darlington, Yolanda; Nguyen, Thuy-Ai; Moon, Sung-Hwan; Herron, Alan; Rao, Pulivarthi; Zhu, Chengming; Lu, Xiongbin; Donehower, Lawrence A.

2011-01-01

Wildtype p53-Induced Phosphatase 1 (WIP1) is a serine/threonine phosphatase that dephosphorylates proteins in the ataxia telangiectasia mutated (ATM)-initiated DNA damage response pathway. WIP1 may play a homeostatic role in ATM signaling by returning the cell to a normal pre-stress state following completion of DNA repair. To better understand the effects of WIP1 on ATM signaling, we crossed Atm-deficient mice to Wip1-deficient mice and characterized phenotypes of the double knockout progeny. We hypothesized that the absence of Wip1 might rescue Atm deficiency phenotypes. Atm null mice, like ATM-deficient humans with the inherited syndrome ataxia telangiectasia, exhibit radiation sensitivity, fertility defects, and are T-cell lymphoma prone. Most double knockout mice were largely protected from lymphoma development and had a greatly extended lifespan compared to Atm null mice. Double knockout mice had increased p53 and H2AX phosphorylation and p21 expression compared to their Atm null counterparts, indicating enhanced p53 and DNA damage responses. Additionally, double knockout splenocytes displayed reduced chromosomal instability compared to Atm null mice. Finally, doubly null mice were partially rescued from infertility defects observed in Atm null mice. These results indicate that inhibition of WIP1 may represent a useful strategy for cancer treatment in general and A-T patients in particular. PMID:21765465

Photoluminescence of Se-related oxygen deficient center in ion-implanted silica films

International Nuclear Information System (INIS)

Zatsepin, A.F.; Buntov, E.A.; Pustovarov, V.A.; Fitting, H.-J.

2013-01-01

The results of low-temperature time-resolved photoluminescence (PL) investigation of thin SiO 2 films implanted with Se + ions are presented. The films demonstrate an intensive PL band in the violet spectral region, which is attributed to the triplet luminescence of a new variant of selenium-related oxygen deficient center (ODC). The main peculiarity of the defect energy structure is the inefficient direct optical excitation. Comparison with spectral characteristics of isoelectronic Si-, Ge- and SnODCs show that the difference in electronic properties of the new center is related to ion size factor. It was established that the dominating triplet PL excitation under VUV light irradiation is related to the energy transfer from SiO 2 excitons. A possible model of Se-related ODC is considered. -- Highlights: • The low-temperature photoluminescence of thin SiO 2 films implanted with Se + ions was studied. • The 3.4 eV PL band was attributed to triplet luminescence of Se-related ODC. • The peculiarity of SeODC electronic properties is related to ion size factor. • The dominating VUV excitation of triplet PL is related to energy transfer from SiO 2 excitons. • A possible model of Se-related ODC is considered

scid mutation in mice confers hypersensitivity to ionizing radiation and a deficiency in DNA double-strand break repair

International Nuclear Information System (INIS)

Biedermann, K.A.; Sun, J.R.; Giaccia, A.J.; Tosto, L.M.; Brown, J.M.

1991-01-01

C.B-17 severe combined immunodeficient (scid) mice carry the scid mutation and are severely deficient in both T cell- and B cell-mediated immunity, apparently as a result of defective V(D)J joining of the immunoglobulin and T-cell receptor gene elements. In the present studies, we have defined the tissue, cellular, and molecular basis of another characteristic of these mice: their hypersensitivity to ionizing radiation. Bone marrow stem cells, intestinal crypt cells, and epithelial skin cells from scid mice are 2- to 3-fold more sensitive when irradiated in situ than are congenic BALB/c or C.B-17 controls. Two independently isolated embryo fibroblastic scid mouse cell lines display similar hypersensitivities to gamma-rays. In addition, these cell lines are sensitive to cell killing by bleomycin, which also produces DNA strand breaks, but not by the DNA crosslinking agent mitomycin C or UV irradiation. Measurement of the rejoining of gamma-ray-induced DNA double-strand breaks by pulsed-field gel electrophoresis indicates that these animals are defective in this repair system. This suggests that the gamma-ray sensitivity of the scid mouse fibroblasts could be the result of reduced repair of DNA double-strand breaks. Therefore, a common factor may participate in both the repair of DNA double-strand breaks as well as V(D)J rejoining during lymphocyte development. This murine autosomal recessive mutation should prove extremely useful in fundamental studies of radiation-induced DNA damage and repair

BRCA1 deficiency increases the sensitivity of ovarian cancer cells to auranofin

International Nuclear Information System (INIS)

Oommen, Deepu; Yiannakis, Dennis; Jha, Awadhesh N.

2016-01-01

Highlights: • BRCA1 deficient cancer cells exhibit increased DNA damage upon auranofin treatment. • Auranofin induces apoptosis in BRCA1 deficient cancer cells despite the activation of Nrf2. • Antioxidant protects BRCA1 deficient cancer cells from auranofin. - Abstract: Auranofin, a thioredoxin reductase inhibitor and an anti-rheumatic drug is currently undergoing phase 2 clinical studies for repurposing to treat recurrent epithelial ovarian cancer. Previous studies have established that auranofin exerts its cytotoxic activity by increasing the production of reactive oxygen species (ROS). Breast cancer 1, early onset (BRCA1) is a DNA repair protein whose functional status is critical in the prognosis of ovarian cancer. Apart from its key role in DNA repair, BRCA1 is also known to modulate cellular redox homeostasis by regulating the stability of anti-oxidant transcription factor, nuclear factor erythroid 2—related factor 2 (Nrf2) via direct protein–protein interaction. However, it is currently unknown whether BRCA1 modulates the sensitivity of ovarian cancer cells to auranofin. Here we report that BRCA1-depleted cells exhibited increased DNA double strand breaks (DSBs) and decreased clonogenic cell survival upon auranofin treatment. Interestingly, auranofin induced the expression of Nrf2 in BRCA1-depleted cells suggesting its regulation independent of BRCA1. Furthermore, anti-oxidant agent, N-acetyl cysteine (NAC) protected BRCA1-depleted cells from DNA damage and apoptosis induced by auranofin. Our study suggests that accumulated lethal DSBs resulting from the oxidative damage render BRCA1 deficient cells more sensitive to auranofin despite the activation of Nrf2.

BRCA1 deficiency increases the sensitivity of ovarian cancer cells to auranofin

Energy Technology Data Exchange (ETDEWEB)

Oommen, Deepu [School of Biological Sciences, Plymouth University, Plymouth PL4 8AA (United Kingdom); Yiannakis, Dennis [Plymouth Oncology Centre, Derriford Hospital, Plymouth Hospitals NHS Trust, Plymouth PL6 8DH (United Kingdom); Jha, Awadhesh N., E-mail: a.jha@plymouth.ac.uk [School of Biological Sciences, Plymouth University, Plymouth PL4 8AA (United Kingdom)

2016-02-15

Highlights: • BRCA1 deficient cancer cells exhibit increased DNA damage upon auranofin treatment. • Auranofin induces apoptosis in BRCA1 deficient cancer cells despite the activation of Nrf2. • Antioxidant protects BRCA1 deficient cancer cells from auranofin. - Abstract: Auranofin, a thioredoxin reductase inhibitor and an anti-rheumatic drug is currently undergoing phase 2 clinical studies for repurposing to treat recurrent epithelial ovarian cancer. Previous studies have established that auranofin exerts its cytotoxic activity by increasing the production of reactive oxygen species (ROS). Breast cancer 1, early onset (BRCA1) is a DNA repair protein whose functional status is critical in the prognosis of ovarian cancer. Apart from its key role in DNA repair, BRCA1 is also known to modulate cellular redox homeostasis by regulating the stability of anti-oxidant transcription factor, nuclear factor erythroid 2—related factor 2 (Nrf2) via direct protein–protein interaction. However, it is currently unknown whether BRCA1 modulates the sensitivity of ovarian cancer cells to auranofin. Here we report that BRCA1-depleted cells exhibited increased DNA double strand breaks (DSBs) and decreased clonogenic cell survival upon auranofin treatment. Interestingly, auranofin induced the expression of Nrf2 in BRCA1-depleted cells suggesting its regulation independent of BRCA1. Furthermore, anti-oxidant agent, N-acetyl cysteine (NAC) protected BRCA1-depleted cells from DNA damage and apoptosis induced by auranofin. Our study suggests that accumulated lethal DSBs resulting from the oxidative damage render BRCA1 deficient cells more sensitive to auranofin despite the activation of Nrf2.

Lung transplantation and survival outcomes in patients with oxygen-dependent COPD with regard to their alpha-1 antitrypsin deficiency status

Directory of Open Access Journals (Sweden)

Ekström M

2017-11-01

Full Text Available Magnus Ekström, Hanan Tanash Department of Respiratory Medicine and Allergology, Skåne University Hospital, Lund University, Lund, Sweden Background: Individuals with severe alpha-1 antitrypsin deficiency (AATD have an increased risk of developing COPD. However, outcomes during long-term oxygen therapy (LTOT in patients with severe AATD and hypoxemia are unknown.Patients and methods: This was a prospective, population-based, consecutive cohort study of patients on LTOT due to COPD in the period from January 1, 1987, to June 30, 2015, in the Swedish National Registry for Respiratory Failure (Swedevox. Severe AATD was identified using the Swedish AATD registry and confirmed by isoelectric focusing. Data on lung transplantation (LTx were obtained from the two lung transplantation centers in Sweden. Mortality and causes of death were assessed based on the National Causes of Death Registry and analyzed using multivariable Cox regression.Results: A total of 14,644 patients who started LTOT due to COPD were included in this study. No patient was lost to follow up. Patients with AATD were younger, included more males and more never smokers, and had fewer comorbidities. During a median follow-up of 1.6 years (interquartile range [IQR], 2.7 on LTOT, patients without severe AATD had a higher mortality, hazard ratio [HR] 1.53 (95% CI, 1.24–1.88, adjusting for age, sex, smoking status, body mass index, performance status, level of hypoxemia, and comorbidities. Cardiovascular deaths were increased. A higher proportion of AATD patients underwent LTx, 53 (19% vs 118 (1%. Survival after LTx was similar for AATD and non-AATD patients and was predicted by age.Conclusion: In oxygen-dependent COPD, patients with severe AATD have a longer survival time on LTOT, but they have a similar prognosis after lung transplantation compared with patients without AATD. Keywords: COPD, long-term oxygen therapy, lung transplantation, severe alpha-1 antitrypsin deficiency

Distribution and Magnitude of Dinitrogen Fixation in the Eastern Tropical North Pacific Oxygen Deficient Zone.

Science.gov (United States)

Selden, C.; Mulholland, M. R.; Widner, B.; Bernhardt, P. W.; Macías Tapia, A.; Jayakumar, A.

2016-12-01

The Eastern Tropical North Pacific Ocean (ETNP) hosts one of the world's three major open ocean oxygen deficient zones (ODZs). Hotspots for fixed nitrogen (N) loss processes, ODZs have classically been discounted as areas of significant dinitrogen (N2) fixation, the microbe-mediated reduction of N2 to ammonium (NH4+), which has historically been ascribed primarily to euphotic, nutrient-deplete tropical waters. Challenging this paradigm, active expression of nifH (the dinitrogen reductase structural gene) has recently been documented in the ETNP, Eastern Tropical South Pacific, and Arabian Sea ODZs, implying a closer coupling of fixed nitrogen input and loss processes than previously thought. Here, we report rates of N­2 fixation measured in the ETNP ODZ along vertical gradients of oxygen, light, and dissolved N concentrations. Detailed vertical profiles of N2 fixation rates and dissolved N concentrations made within the ODZ were compared with similar profiles from oxic waters outside the ODZ. In addition, different organic carbon sources were investigated as potential rate-limiting factors for N2 fixation in sub-euphotic waters. By establishing the magnitude and distribution of N­2 fixation in the ETNP ODZ, this study contributes to current understanding of N cycling in anoxic and aphotic waters, and serves to elucidate nuances in the global N budget, enabling more accurate biogeochemical modeling. Understanding these processes in present day ODZs is crucial for predicting how ongoing anthropogenic intensification of coastal ODZs will alter biogeochemical cycles in the future.

The double-well oscillating potential of oxygen atoms in perovskite system Ba(K)BiO sub 3 : EXAFS - analysis results

CERN Document Server

Menushenkov, A P; Konarev, P V; Meshkov, A A; Benazeth, S; Purans, J

2000-01-01

Temperature-dependent X-ray absorption investigations were made on the Bi L sub 3 -edge in Ba sub 1 sub - sub x K sub x BiO sub 3 with x=0.0, 0.4 and 0.5. For the superconducting samples (x=0.4 and 0.5) it has been found that the local structure differs from the ideal cubic in contrast to the neutron and X-ray diffraction data. The provided analysis of the EXAFS spectra indicates that the oxygen atoms move in double-well potential produced by the existence of two non-equivalent octahedral types of the oxygen environment of bismuth. The vibrations in such a potential lead to modulations of the Bi-O lengths with low frequency which is determined by the soft oxygen octahedron rotation mode frequency. This induces strong electron-phonon interaction and may be the reason for relatively high-temperature transition (T sub c approx 30 K) to the superconducting state.

Usefulness of extracorporeal membrane oxygenation using double roller pumps in a low body weight newborn: A novel strategy for mechanical circulatory support in an infant

Directory of Open Access Journals (Sweden)

Keisuke Nakanishi

2016-01-01

Full Text Available Extracorporeal membrane oxygenation (ECMO with a centrifugal pump requires a certain flow rate; therefore, its application for low body weight infants is frequently accompanied by oxygenator membrane malfunction and/or inadequate perfusion. To prevent low-flow associated complications, we report a case in which a novel system of dual roller pumps was used. A baby girl with a body mass index 0.25 m 2 , who experienced difficulty weaning from cardiopulmonary bypass after a Norwood-like operation, required an ECMO. Concerns for the tube lifespan reduction due to roller pump friction led to the use of a double roller pump circulation. The termination of ECMO during tube exchange is not needed, because circulation is maintained by another roller pump. The novel strategy of ECMO with double roller pumps will allow low perfusion rate to provide adequate circulatory support for low body weight patients.

Cluster Differentiating 36 (CD36) Deficiency Attenuates Obesity-Associated Oxidative Stress in the Heart.

Science.gov (United States)

Gharib, Mohamed; Tao, Huan; Fungwe, Thomas V; Hajri, Tahar

2016-01-01

Obesity is often associated with a state of oxidative stress and increased lipid deposition in the heart. More importantly, obesity increases lipid influx into the heart and induces excessive production of reactive oxygen species (ROS) leading to cell toxicity and metabolic dysfunction. Cluster differentiating 36 (CD36) protein is highly expressed in the heart and regulates lipid utilization but its role in obesity-associated oxidative stress is still not clear. The aim of this study was to determine the impact of CD36 deficiency on cardiac steatosis, oxidative stress and lipotoxicity associated with obesity. Studies were conducted in control (Lean), obese leptin-deficient (Lepob/ob) and leptin-CD36 double null (Lepob/obCD36-/-) mice. Compared to lean mice, cardiac steatosis, and fatty acid (FA) uptake and oxidation were increased in Lepob/ob mice, while glucose uptake and oxidation was reduced. Moreover, insulin resistance, oxidative stress markers and NADPH oxidase-dependent ROS production were markedly enhanced. This was associated with the induction of NADPH oxidase expression, and increased membrane-associated p47phox, p67phox and protein kinase C. Silencing CD36 in Lepob/ob mice prevented cardiac steatosis, increased insulin sensitivity and glucose utilization, but reduced FA uptake and oxidation. Moreover, CD36 deficiency reduced NADPH oxidase activity and decreased NADPH oxidase-dependent ROS production. In isolated cardiomyocytes, CD36 deficiency reduced palmitate-induced ROS production and normalized NADPH oxidase activity. CD36 deficiency prevented obesity-associated cardiac steatosis and insulin resistance, and reduced NADPH oxidase-dependent ROS production. The study demonstrates that CD36 regulates NADPH oxidase activity and mediates FA-induced oxidative stress.

Alarm points for fixed oxygen monitors

International Nuclear Information System (INIS)

Miller, G.C.

1987-05-01

Oxygen concentration monitors were installed in a vault where numerous pipes carried inert cryogens and gases to the Mirror Fusion Test Facility (MFTF-B) experimental vessel at Lawrence Livermore National Laboratory (LLNL). The problems associated with oxygen-monitoring systems and the reasons why such monitors were installed were reviewed. As a result of this review, the MFTF-B monitors were set to sound an evacuation alarm when the oxygen concentration fell below 18%. We chose the 18% alarm criterion to minimize false alarms and to allow time for personnel to escape in an oxygen-deficient environment

High Rate and Stable Li-Ion Insertion in Oxygen-Deficient LiV3O8 Nanosheets as a Cathode Material for Lithium-Ion Battery.

Science.gov (United States)

Song, Huanqiao; Luo, Mingsheng; Wang, Aimei

2017-01-25

Low performance of cathode materials has become one of the major obstacles to the application of lithium-ion battery (LIB) in advanced portable electronic devices, hybrid electric vehicles, and electric vehicles. The present work reports a versatile oxygen-deficient LiV 3 O 8 (D-LVO) nanosheet that was synthesized successfully via a facile oxygen-deficient hydrothermal reaction followed by thermal annealing in Ar. When used as a cathode material for LIB, the prepared D-LVO nanosheets display remarkable capacity properties at various current densities (a capacity of 335, 317, 278, 246, 209, 167, and 133 mA h g -1 at 50, 100, 200, 500, 1000, 2000, and 4000 mA g -1 , respectively) and excellent lithium-ion storage stability, maintaining more than 88% of the initial reversible capacity after 200 cycles at 1000 mA g -1 . The outstanding electrochemical properties are believed to arise largely from the introduction of tetravalent V (∼15% V 4+ ) and the attendant oxygen vacancies into LiV 3 O 8 nanosheets, leading to intrinsic electrical conductivity more than 1 order of magnitude higher and lithium-ion diffusion coefficient nearly 2 orders of magnitude higher than those of LiV 3 O 8 without detectable V 4+ (N-LVO) and thus contributing to the easy lithium-ion diffusion, rapid phase transition, and the excellent electrochemical reversibility. Furthermore, the more uniform nanostructure, as well as the larger specific surface area of D-LVO than N-LVO nanosheets may also improve the electrolyte penetration and provide more reaction sites for fast lithium-ion diffusion during the discharge/charge processes.

In HepG2 cells, coexisting carnitine deficiency masks important indicators of marginal biotin deficiency.

Science.gov (United States)

Bogusiewicz, Anna; Boysen, Gunnar; Mock, Donald M

2015-01-01

A large number of birth defects are related to nutrient deficiencies; concern that biotin deficiency is teratogenic in humans is reasonable. Surprisingly, studies indicate that increased urinary 3-hydroxyisovalerylcarnitine (3HIAc), a previously validated marker of biotin deficiency, is not a valid biomarker in pregnancy. In this study we hypothesized that coexisting carnitine deficiency can prevent the increase in 3HIAc due to biotin deficiency. We used a 2-factor nutrient depletion design to induce isolated and combined biotin and carnitine deficiency in HepG2 cells and then repleted cells with carnitine. To elucidate the metabolic pathogenesis, we quantitated intracellular and extracellular free carnitine, acylcarnitines, and acylcarnitine ratios using liquid chromatography-tandem mass spectrometry. Relative to biotin-sufficient, carnitine-sufficient cells, intracellular acetylcarnitine increased by 90%, propionylcarnitine more than doubled, and 3HIAc increased by >10-fold in biotin-deficient, carnitine-sufficient (BDCS) cells, consistent with a defensive mechanism in which biotin-deficient cells transesterify the acyl-coenzyme A (acyl-CoA) substrates of the biotin-dependent carboxylases to the related acylcarnitines. Likewise, in BDCS cells, the ratio of acetylcarnitine to malonylcarnitine and the ratio of propionylcarnitine to methylmalonylcarnitine both more than tripled, and the ratio of 3HIAc to 3-methylglutarylcarnitine (MGc) increased by >10-fold. In biotin-deficient, carnitine-deficient (BDCD) cells, the 3 substrate-derived acylcarnitines changed little, but the substrate:product ratios were masked to a lesser extent. Moreover, carnitine repletion unmasked biotin deficiency in BDCD cells as shown by increases in acetylcarnitine, propionylcarnitine, and 3HIAc (each increased by >50-fold). Likewise, ratios of acetylcarnitine:malonylcarnitine, propionylcarnitine:methylmalonylcarnitine, and 3HIAc:MGc all increased by >8-fold. Our findings provide strong

Upper-critical fields of YBa2Cu3O7-δ epitaxial thin films with variable oxygen deficiency δ

International Nuclear Information System (INIS)

Jones, E.C.; Christen, D.K.; Thompson, J.R.; Ossandon, J.G.; Feenstra, R.; Phillips, J.M.; Siegal, M.P.

1994-01-01

Fluctuation analysis in the limit of high magnetic fields was performed on three epitaxial thin films of YBa 2 Cu 3 O 7-δ for various oxygen deficiencies δ c2 (T) slope of -1.7 T/K for H parallel c, consistent with previous observations of transport and magnetic properties. Moreover, the 3D scaling showed better convergence than the 2D scaling, which gave relatively low values of H c2 . In contrast, the transitions were not adequately described by either scaling for T c off the 90-K plateau; it is speculated that this is due to an extrinsic broadening of the transitions, possibly due to the lack of a complete percolation path of the ortho-I phase (δ=0)

Effect of oxygen on inactivation of biologically active DNA by γ rays in vitro: influence of metalloporphyrins and enzymatic DNA repair

International Nuclear Information System (INIS)

van Hemmen, J.J.; Meuling, W.J.A.; Bleichrodt, J.F.

1978-01-01

Biologically active DNA dissolved in a bacterial extract shows a higher sensitivity to γ rays under oxygen than under anoxic conditions. This oxygen effect depends on the presence of dialyzable, probably organometallic, compounds in the extract. Metalloporphyrins mimic these cellular components with regard to the effect of oxygen on DNA irradiated in vitro. Anoxic irradiation leads to less double-strand breaks in the DNA than irradiation under oxygen, but the oxygen effect in vitro is mainly due to nucleotide damage. No oxygen effect is observed when the biological activity of the irradiated DNA is assayed on spheroplasts of a bacterial strain carrying a uvrA mutation, i.e., a deficiency in the excision repair system, and the sensitivity of the DNA is almost equal to that found for irradiation under oxygen and assay on a repair-proficient strain. It may be concluded, therefore, that the oxygen effect observed with DNA in cellular extracts or in the presence of metalloporphyrins results from more efficient cellular repair of the otherwise lethal nucleotide damage inflicted under anoxic conditions. Comparison of the oxygen effect on DNA in vitro with the radiosensitization of bacterial cells by oxygen shows that in bacteria part of the radiation damage may be similar to that induced in DNA in vitro, but, in addition, the cells sustain another type of damage which is subjected to an oxygen effect but not to excision repair

In HepG2 Cells, Coexisting Carnitine Deficiency Masks Important Indicators of Marginal Biotin Deficiency123

Science.gov (United States)

Bogusiewicz, Anna; Boysen, Gunnar; Mock, Donald M

2015-01-01

Background: A large number of birth defects are related to nutrient deficiencies; concern that biotin deficiency is teratogenic in humans is reasonable. Surprisingly, studies indicate that increased urinary 3-hydroxyisovalerylcarnitine (3HIAc), a previously validated marker of biotin deficiency, is not a valid biomarker in pregnancy. Objective: In this study we hypothesized that coexisting carnitine deficiency can prevent the increase in 3HIAc due to biotin deficiency. Methods: We used a 2-factor nutrient depletion design to induce isolated and combined biotin and carnitine deficiency in HepG2 cells and then repleted cells with carnitine. To elucidate the metabolic pathogenesis, we quantitated intracellular and extracellular free carnitine, acylcarnitines, and acylcarnitine ratios using liquid chromatography–tandem mass spectrometry. Results: Relative to biotin-sufficient, carnitine-sufficient cells, intracellular acetylcarnitine increased by 90%, propionylcarnitine more than doubled, and 3HIAc increased by >10-fold in biotin-deficient, carnitine-sufficient (BDCS) cells, consistent with a defensive mechanism in which biotin-deficient cells transesterify the acyl-coenzyme A (acyl-CoA) substrates of the biotin-dependent carboxylases to the related acylcarnitines. Likewise, in BDCS cells, the ratio of acetylcarnitine to malonylcarnitine and the ratio of propionylcarnitine to methylmalonylcarnitine both more than tripled, and the ratio of 3HIAc to 3-methylglutarylcarnitine (MGc) increased by >10-fold. In biotin-deficient, carnitine-deficient (BDCD) cells, the 3 substrate-derived acylcarnitines changed little, but the substrate:product ratios were masked to a lesser extent. Moreover, carnitine repletion unmasked biotin deficiency in BDCD cells as shown by increases in acetylcarnitine, propionylcarnitine, and 3HIAc (each increased by >50-fold). Likewise, ratios of acetylcarnitine:malonylcarnitine, propionylcarnitine:methylmalonylcarnitine, and 3HIAc:MGc all increased

Efficacy of a microencapsulated iron pyrophosphate-fortified fruit juice: a randomised, double-blind, placebo-controlled study in Spanish iron-deficient women.

Science.gov (United States)

Blanco-Rojo, Ruth; Pérez-Granados, Ana M; Toxqui, Laura; González-Vizcayno, Carmen; Delgado, Marco A; Vaquero, M Pilar

2011-06-01

Fe-deficiency anaemia is a worldwide health problem. We studied the influence of consuming an Fe-fortified fruit juice on Fe status in menstruating women. A randomised, double-blind, placebo-controlled study of 16 weeks of duration was performed. Subjects were randomised into two groups: the P group (n 58) or the F group (n 64), and consumed, as a supplement to their usual diet, 500 ml/d of a placebo fruit juice or an Fe-fortified fruit juice, respectively. The Fe-fortified fruit juice, containing microencapsulated iron pyrophosphate, provided 18 mg Fe/d (100 % of the RDA). At baseline and monthly, dietary intake, body weight and Fe parameters were determined: total erythrocytes, haematocrit, mean corpuscular volume (MCV), red blood cell distribution width (RDW), Hb, serum Fe, serum ferritin, serum transferrin, transferrin saturation, soluble transferrin receptor (sTfR) and zinc protoporphyrin (ZnPP). The fruit juice consumption involved increased intake of carbohydrates and vitamin C, and increased BMI within normal limits. Ferritin was higher in the F group after week 4 (P juice improves Fe status and may be used to prevent Fe-deficiency anaemia.

Towards forming-free resistive switching in oxygen engineered HfO{sub 2−x}

Energy Technology Data Exchange (ETDEWEB)

Sharath, S. U., E-mail: sharath@oxide.tu-darmstadt.de; Kurian, J.; Hildebrandt, E.; Alff, L. [Institute of Materials Science, Technische Universität Darmstadt, Alarich-Weiss-Strasse 2, 64287 Darmstadt (Germany); Bertaud, T.; Walczyk, C.; Calka, P.; Zaumseil, P.; Sowinska, M.; Walczyk, D. [IHP, Im Technologiepark 25, 15236 Frankfurt Oder (Germany); Gloskovskii, A. [Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg (Germany); Schroeder, T. [IHP, Im Technologiepark 25, 15236 Frankfurt Oder (Germany); Brandenburgische Technische Universität, Konrad-Zuse-Strasse 1, 03046 Cottbus (Germany)

2014-02-10

We have investigated the resistive switching behavior in stoichiometric HfO{sub 2} and oxygen-deficient HfO{sub 2−x} thin films grown on TiN electrodes using reactive molecular beam epitaxy. Oxygen defect states were controlled by the flow of oxygen radicals during thin film growth. Hard X-ray photoelectron spectroscopy confirmed the presence of sub-stoichiometric hafnium oxide and defect states near the Fermi level. The oxygen deficient HfO{sub 2−x} thin films show bipolar switching with an electroforming occurring at low voltages and low operating currents, paving the way for almost forming-free devices for low-power applications.

Seasonal oxygen deficiency over the western continental shelf of India

Digital Repository Service at National Institute of Oceanography (India)

Naqvi, S.W.A.; Naik, H.; Jayakumar, D.A.; Shailaja, M.S.; Narvekar, P.V.

, and their impact on biology and chemistry off the west coast of India are described here. The O2 deficiency in this region, associated with the seasonal (southwest monsoon) upwelling, seems to have intensified in recent years, presumably in response to enhanced...

Oxygen transport through soft contact lens and cornea: Lens characterization and metabolic modeling

Science.gov (United States)

Chhabra, Mahendra

The human cornea requires oxygen to sustain metabolic processes critical for its normal functioning. Any restriction to corneal oxygen supply from the external environment (e.g., by wearing a low oxygen-permeability contact lens) can lead to hypoxia, which may cause corneal edema (swelling), limbal hyperemia, neovascularization, and corneal acidosis. The need for adequate oxygen to the cornea is a major driving force for research and development of hypertransmissible soft contact lenses (SCLs). Currently, there is no standard technique for measuring oxygen permeability (Dk) of hypertransmissible silicone-hydrogel SCLs. In this work, an electrochemistry-based polarographic apparatus was designed, built, and operated to measure oxygen permeability in hypertransmissible SCLs. Unlike conventional methods where a range of lens thickness is needed for determining oxygen permeabilities of SCLs, this apparatus requires only a single lens thickness. The single-lens permeameter provides a reliable, efficient, and economic tool for measuring oxygen permeabilities of commercial hypertransmissible SCLs. The single-lens permeameter measures not only the product Dk, but, following modification, it measures separately diffusivity, D, and solubility, k, of oxygen in hypertransmissible SCLs. These properties are critical for designing better lens materials that ensure sufficient oxygen supply to the cornea. Metabolism of oxygen in the cornea is influenced by contact-lens-induced hypoxia, diseases such as diabetes, surgery, and drug treatment, Thus, estimation of the in-vivo corneal oxygen consumption rate is essential for gauging adequate oxygen supply to the cornea. Therefore, we have developed an unsteady-state reactive-diffusion model for the cornea-contact-lens system to determine in-vivo human corneal oxygen-consumption rate. Finally, a metabolic model was developed to determine the relation between contact-lens oxygen transmissibility (Dk/L) and corneal oxygen deficiency. A

Cytotoxicity of 125I decay in the DNA double strand break repair deficient mutant cell line, xrs-5

International Nuclear Information System (INIS)

Yasui, L.S.

1992-01-01

Survival of parental Chinese hamster ovary (CHO) K1 cells and the DNA double strand break (DSB) repair deficient mutant, xrs-5 was determined after accumulation of 125 I decays. Both CHO and xrs-5 cells were extremely sensitive to accumulated 125 I decays. D o values for CHO and xrs-5 cells were 40 and approximately 7 decays per cell, respectively. Difference in cell survival between CHO and xrs-5 cells was not due to differences in overall 125 IUdR incorporation, differences in labelling index (LI) or differences in plating efficiency (PE). Relative biological effectiveness (RBE) values calculated relative to 137 Cs gamma radiation survival values (D o and D 10 ) were higher in xrs-5 cells compared with CHO cells, although both CHO and xrs-5 cells have high RBE values that correspond to a high sensitivity of CHO and xrs-5 cells to 125 I decay. (Author)

Structural and superconducting properties of oxygen-deficient NdBa sub 2 Cu sub 3 O sub 7 minus. delta

Energy Technology Data Exchange (ETDEWEB)

Shaked, H. (Nuclear Research Center-Negev, Post Office Box 9001, Beer Sheva, Israel (IL) Ben Gurion University of the Negev, Post Office Box 653, Beer Sheva, Israel (IL)); Veal, B.W.; Faber, J. Jr.; Hitterman, R.L.; Balachandran, U.; Tomlins, G.; Shi, H.; Morss, L.; Paulikas, A.P. (Argonne National Laboratory, Argonne, Illinois 60439 (USA))

1990-03-01

Neutron diffraction was used to determine the structural properties of oxygen deficient NdBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} for 0.09{lt}{delta}{lt}0.74. It was found that superconductivity disappears at the orthorhombic-to-tetragonal phase transition which occurs at {delta}{sub {ital O}{ital T}}=0.45. Structural parameters vary smoothly with {delta} but exhibit a change in slope at the orthorhombic-to-tetragonal transition. The structural properties exhibit the same features found in YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} where {delta}{sub {ital O}{ital T}}=0.65. It is shown that the repulsion energy of oxygen atoms in the O(1) and O(5) sites in NdBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} is smaller than in YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}. This lower repulsion energy stabilizes the orthorhombic phase at lower values of {delta}. It is argued that the disappearance of superconductivity at the orthorhombic-to-tetragonal transition is an inherent property of the {ital R}Ba{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} ({ital R} denotes rare earth) system.

Identification and quantification of nitrogen nutrient deficiency in the activated sludge process using respirometry

NARCIS (Netherlands)

Ning, Z.; Patry, G.G.; Spanjers, H.

2000-01-01

Experimental protocols to identify and quantify nitrogen nutrient deficiency in the activated sludge process were developed and tested using respirometry. Respirometric experiments showed that when a nitrogen nutrient deficient sludge is exposed to ammonia nitrogen, the oxygen uptake rate (OUR) of

Host-Guest Engineering of Layered Double Hydroxides towards Efficient Oxygen Evolution Reaction: Recent Advances and Perspectives

Directory of Open Access Journals (Sweden)

Jianming Li

2018-05-01

Full Text Available Electrochemical water splitting has great potential in the storage of intermittent energy from the sun, wind, or other renewable sources for sustainable clean energy applications. However, the anodic oxygen evolution reaction (OER usually determines the efficiency of practical water electrolysis due to its sluggish four-electron process. Layered double hydroxides (LDHs have attracted increasing attention as one of the ideal and promising electrocatalysts for water oxidation due to their excellent activity, high stability in basic conditions, as well as their earth-abundant compositions. In this review, we discuss the recent progress on LDH-based OER electrocatalysts in terms of active sites, host-guest engineering, and catalytic performances. Moreover, further developments and challenges in developing promising electrocatalysts based on LDHs are discussed from the viewpoint of molecular design and engineering.

Pion double charge exchange

International Nuclear Information System (INIS)

Cooper, M.D.

1978-01-01

The pion double charge exchange data on the oxygen isotopes is reviewed and new data on 9 Be, 12 C, 24 Mg, and 28 Si are presented. Where theoretical calculations exist, they are compared to the data. 9 references

Magnetic studies of current conduction and flux pinning in high-Tc cuprates: Virgin, irradiated, and oxygen deficient materials

International Nuclear Information System (INIS)

Thompson, J.R.; Civale, L.; Marwick, A.D.; Holtzberg, F.

1992-09-01

To increase the current density and pinning of magnetic flux in high temperature superconductors, defects with point-like and line-like geometries were created in controlled numbers using ion irradiation methods. Single crystals of Y 1 Ba 2 Cu 3 O 7 and Bi 2 Sr 2 Ca 1 Cu 2 0 8 superconductors were studied using dc magnetic methods. These studies showed greatly increased irreversibility in the vortex state magnetization and enhanced intragrain current density J c following irradiation. Linear defects, created by irradiation with energetic heavy ions, are particularly effective in pinning vortices at higher temperatures and magnetic fields. Further investigations of ''flux creep'' (the time dependence of magnetization) are well described by recent vortex glass and collective pinning theories. Complementary investigations have delineated the role of oxygen deficiency δ on pinning in aligned Y 1 Ba 2 Cu 3 O 7-δ materials

The double burden of undernutrition and excess body weight in Ecuador.

Science.gov (United States)

Freire, Wilma B; Silva-Jaramillo, Katherine M; Ramírez-Luzuriaga, María J; Belmont, Philippe; Waters, William F

2014-12-01

Ecuador's current nutrition policies have not taken adequate notice of the double burden of malnutrition and continue to focus on stunting and to a lesser extent on overweight, without addressing the simultaneous presence of undernutrition, micronutrient deficiencies, and overweight or obesity (OW/OB). The aim of this article was to describe the prevalence and distribution of undernutrition (stunting, anemia, and zinc deficiency), overweight, and obesity in Ecuador to explore the evolving double burden of malnutrition at the national, household, and individual levels and to discuss whether current public health policies are addressing the double burden. Data from the 2012 Ecuadorian National Health and Nutrition Survey (ENSANUT-ECU) was used to estimate the dual burden of malnutrition at the national, household, and individual levels in children Ecuador. Although integrated approaches to address the emerging double burden are required, public health policies to date have not responded adequately. © 2014 American Society for Nutrition.

Identifying activated T cells in reconstituted RAG deficient mice using retrovirally transduced Pax5 deficient pro-B cells.

Directory of Open Access Journals (Sweden)

Nadesan Gajendran

Full Text Available Various methods have been used to identify activated T cells such as binding of MHC tetramers and expression of cell surface markers in addition to cytokine-based assays. In contrast to these published methods, we here describe a strategy to identify T cells that respond to any antigen and track the fate of these activated T cells. We constructed a retroviral double-reporter construct with enhanced green fluorescence protein (EGFP and a far-red fluorescent protein from Heteractis crispa (HcRed. LTR-driven EGFP expression was used to enrich and identify transduced cells, while HcRed expression is driven by the CD40Ligand (CD40L promoter, which is inducible and enables the identification and cell fate tracing of T cells that have responded to infection/inflammation. Pax5 deficient pro-B cells that can give rise to different hematopoietic cells like T cells, were retrovirally transduced with this double-reporter cassette and were used to reconstitute the T cell pool in RAG1 deficient mice that lack T and B cells. By using flow cytometry and histology, we identified activated T cells that had developed from Pax5 deficient pro-B cells and responded to infection with the bacterial pathogen Listeria monocytogenes. Microscopic examination of organ sections allowed visual identification of HcRed-expressing cells. To further characterize the immune response to a given stimuli, this strategy can be easily adapted to identify other cells of the hematopoietic system that respond to infection/inflammation. This can be achieved by using an inducible reporter, choosing the appropriate promoter, and reconstituting mice lacking cells of interest by injecting gene-modified Pax5 deficient pro-B cells.

DNA repair deficiency in neurodegeneration

DEFF Research Database (Denmark)

Jeppesen, Dennis Kjølhede; Bohr, Vilhelm A; Stevnsner, Tinna V.

2011-01-01

Deficiency in repair of nuclear and mitochondrial DNA damage has been linked to several neurodegenerative disorders. Many recent experimental results indicate that the post-mitotic neurons are particularly prone to accumulation of unrepaired DNA lesions potentially leading to progressive...... neurodegeneration. Nucleotide excision repair is the cellular pathway responsible for removing helix-distorting DNA damage and deficiency in such repair is found in a number of diseases with neurodegenerative phenotypes, including Xeroderma Pigmentosum and Cockayne syndrome. The main pathway for repairing oxidative...... base lesions is base excision repair, and such repair is crucial for neurons given their high rates of oxygen metabolism. Mismatch repair corrects base mispairs generated during replication and evidence indicates that oxidative DNA damage can cause this pathway to expand trinucleotide repeats, thereby...

Does vitamin C deficiency affect cognitive development and function?

DEFF Research Database (Denmark)

Hansen, Stine Normann; Tveden-Nyborg, Pernille; Lykkesfeldt, Jens

2014-01-01

Vitamin C is a pivotal antioxidant in the brain and has been reported to have numerous functions, including reactive oxygen species scavenging, neuromodulation, and involvement in angiogenesis. Absence of vitamin C in the brain has been shown to be detrimental to survival in newborn SVCT2(-/-) mice...... and perinatal deficiency have shown to reduce hippocampal volume and neuron number and cause decreased spatial cognition in guinea pigs, suggesting that maternal vitamin C deficiency could have severe consequences for the offspring. Furthermore, vitamin C deficiency has been proposed to play a role in age......-related cognitive decline and in stroke risk and severity. The present review discusses the available literature on effects of vitamin C deficiency on the developing and aging brain with particular focus on in vivo experimentation and clinical studies....

Controlling Oxygen Mobility in Ruddlesden–Popper Oxides

Directory of Open Access Journals (Sweden)

Dongkyu Lee

2017-03-01

Full Text Available Discovering new energy materials is a key step toward satisfying the needs for next-generation energy conversion and storage devices. Among the various types of oxides, Ruddlesden–Popper (RP oxides (A2BO4 are promising candidates for electrochemical energy devices, such as solid oxide fuel cells, owing to their attractive physicochemical properties, including the anisotropic nature of oxygen migration and controllable stoichiometry from oxygen excess to oxygen deficiency. Thus, understanding and controlling the kinetics of oxygen transport are essential for designing optimized materials to use in electrochemical energy devices. In this review, we first discuss the basic mechanisms of oxygen migration in RP oxides depending on oxygen nonstoichiometry. We then focus on the effect of changes in the defect concentration, crystallographic orientation, and strain on the oxygen migration in RP oxides. We also briefly review their thermal and chemical stability. Finally, we conclude with a perspective on potential research directions for future investigation to facilitate controlling oxygen ion migration in RP oxides.

Combined Increases in Mitochondrial Cooperation and Oxygen Photoreduction Compensate for Deficiency in Cyclic Electron Flow in Chlamydomonas reinhardtii[W][OPEN

Science.gov (United States)

Dang, Kieu-Van; Plet, Julie; Tolleter, Dimitri; Jokel, Martina; Cuiné, Stéphan; Carrier, Patrick; Auroy, Pascaline; Richaud, Pierre; Johnson, Xenie; Alric, Jean; Allahverdiyeva, Yagut; Peltier, Gilles

2014-01-01

During oxygenic photosynthesis, metabolic reactions of CO2 fixation require more ATP than is supplied by the linear electron flow operating from photosystem II to photosystem I (PSI). Different mechanisms, such as cyclic electron flow (CEF) around PSI, have been proposed to participate in reequilibrating the ATP/NADPH balance. To determine the contribution of CEF to microalgal biomass productivity, here, we studied photosynthesis and growth performances of a knockout Chlamydomonas reinhardtii mutant (pgrl1) deficient in PROTON GRADIENT REGULATION LIKE1 (PGRL1)–mediated CEF. Steady state biomass productivity of the pgrl1 mutant, measured in photobioreactors operated as turbidostats, was similar to its wild-type progenitor under a wide range of illumination and CO2 concentrations. Several changes were observed in pgrl1, including higher sensitivity of photosynthesis to mitochondrial inhibitors, increased light-dependent O2 uptake, and increased amounts of flavodiiron (FLV) proteins. We conclude that a combination of mitochondrial cooperation and oxygen photoreduction downstream of PSI (Mehler reactions) supplies extra ATP for photosynthesis in the pgrl1 mutant, resulting in normal biomass productivity under steady state conditions. The lower biomass productivity observed in the pgrl1 mutant in fluctuating light is attributed to an inability of compensation mechanisms to respond to a rapid increase in ATP demand. PMID:24989042

p53-competent cells and p53-deficient cells display different susceptibility to oxygen functionalized graphene cytotoxicity and genotoxicity.

Science.gov (United States)

Petibone, Dayton M; Mustafa, Thikra; Bourdo, Shawn E; Lafont, Andersen; Ding, Wei; Karmakar, Alokita; Nima, Zeid A; Watanabe, Fumiya; Casciano, Daniel; Morris, Suzanne M; Dobrovolsky, Vasily N; Biris, Alexandru S

2017-11-01

Due to the distinctive physical, electrical, and chemical properties of graphene nanomaterials, numerous efforts pursuing graphene-based biomedical and industrial applications are underway. Oxidation of pristine graphene surfaces mitigates its otherwise hydrophobic characteristic thereby improving its biocompatibility and functionality. Yet, the potential widespread use of oxidized graphene derivatives raises concern about adverse impacts on human health. The p53 tumor suppressor protein maintains cellular and genetic stability after toxic exposures. Here, we show that p53 functional status correlates with oxygen functionalized graphene (f-G) cytotoxicity and genotoxicity in vitro. The f-G exposed p53-competent cells, but not p53-deficient cells, initiated G 0 /G 1 phase cell cycle arrest, suppressed reactive oxygen species, and entered apoptosis. There was p53-dependent f-G genotoxicity evident as increased structural chromosome damage, but not increased gene mutation or chromatin loss. In conclusion, the cytotoxic and genotoxic potential for f-G in exposed cells was dependent on the p53 functional status. These findings have broad implications for the safe and effective implementation of oxidized graphene derivatives into biomedical and industrial applications. Published 2017. This article has been contributed to by US Government employees and their work is in the public domain in the USA. Published 2017. This article has been contributed to by US Government employees and their work is in the public domain in the USA.

Fluorination of an epitaxial YBaCuO thin film with controlled oxygen vacancies

Energy Technology Data Exchange (ETDEWEB)

Perrin, C. (Lab. de Chimie du Solide et Inorganique Moleculaire, Univ. de Rennes 1, 35 (France)); Pena, O. (Lab. de Chimie du Solide et Inorganique Moleculaire, Univ. de Rennes 1, 35 (France)); Mokhtari, M. (Lab. de Chimie du Solide et Inorganique Moleculaire, Univ. de Rennes 1, 35 (France)); Thivet, C. (Lab. de Chimie du Solide et Inorganique Moleculaire, Univ. de Rennes 1, 35 (France)); Guilloux-Viry, M. (Lab. de Chimie du Solide et Inorganique Moleculaire, Univ. de Rennes 1, 35 (France)); Perrin, A. (Lab. de Chimie du Solide et Inorganique Moleculaire, Univ. de Rennes 1, 35 (France)); Sergent, M. (Lab. de Chimie du Solide et Inorganique Moleculaire, Univ. de Rennes 1, 35 (France))

1993-05-10

An intentionally oxygen-deficient thin film, epitaxially grown in-situ on a (100) MgO substrate by laser ablation at 750 C under a low pressure oxygen atmosphere, has been treated under NF[sub 3] diluted in N[sub 2] at temperatures not exceeding 280 C. During the fluorination process the epitaxy of the thin film is maintained; its Tc onset progressively increases from 54 K up to 85.6 K and the width of the inductive transition is narrow at the end of treatment (1.2 K). These results are discussed and compared to those obtained during the fluorination of oxygen-deficient YBa[sub 2]Cu[sub 3]O[sub x] ceramics. (orig.)

Oxygen vacancies induced enhancement of photoconductivity of La0.5Sr0.5CoO3 - δ thin film

Science.gov (United States)

Gao, R. L.; Fu, C. L.; Cai, W.; Chen, G.; Deng, X. L.; Yang, H. W.; Sun, J. R.; Zhao, Y. G.; Shen, B. G.

2014-09-01

Effects of light and electrical current on the electrical transport properties and photovoltaic properties of oxygen-stoichiometric La0.5Sr0.5CoO3 and oxygen-deficient La0.5Sr0.5CoO3 - δ films prepared by pulsed laser deposition have been investigated. Oxygen-deficient films annealed in a vacuum show an obvious increase of resistance and lattice parameter. Besides, a direct correlation between the magnitude of the photoconductivity and oxygen vacancies in La0.5Sr0.5CoO3 - δ films has been observed. The light illumination causes a resistance drop to show the photoconductivity effect. Moreover, the photoconductivity can be remarkably enhanced by increasing the electrical current, that is, it exhibits current-enhanced photoconductivity (CEPC) effect. Oxygen deficiency in the annealed film leads to the formation of a structural disorder in the Co-O-Co conduction channel due to the accumulated oxygen vacancies and hence is believed to be responsible for the increase in higher photoconductivity. These results may be important for practical applications in photoelectric devices.

Radioprotective effect of cysteamine in glutathione synthetase-deficient cells

International Nuclear Information System (INIS)

Deschavanne, P.J.; Debieu, D.; Malaise, E.P.; Midander, J.; Revesz, L.

1986-01-01

The radioprotective role of endogenous and exogenous thiols was investigated, with survival as the end-point, after radiation exposure of cells under oxic and hypoxic conditions. Human cell strains originating from a 5-oxoprolinuria patient and from a related control were used. Due to a genetic deficiency in glutathione synthetase, the level of free SH groups, and in particular that of glutathione, is decreased in 5-oxoprolinuria cells. The glutathione synthetase deficient cells have a reduced oxygen enhancement ratio (1.5) compared to control cells (2.7). The radiosensitivity was assessed for both cell strains in the presence of different concentrations of an exogenous radioprotector:cysteamine. At concentrations varying between 0.1 and 20 mM, cysteamine protected the two cell strains to the same extent when irradiated under oxic and hypoxic conditions. The protective effect of cysteamine was lower under hypoxia than under oxic conditions for both cell strains. Consequently, the oxygen enhancement ratio decreased for both cell strains when cysteamine concentration increased. These results suggest that cysteamine cannot replace endogenous thiols as far as they are implicated in the radiobiological oxygen effect. (author)

NiMn layered double hydroxide nanosheets/NiCo2O4 nanowires with surface rich high valence state metal oxide as an efficient electrocatalyst for oxygen evolution reaction

Science.gov (United States)

Yang, Liting; Chen, Lin; Yang, Dawen; Yu, Xu; Xue, Huaiguo; Feng, Ligang

2018-07-01

High valence transition metal oxide is significant for anode catalyst of proton membrane water electrolysis technique. Herein, we demonstrate NiMn layered double hydroxide nanosheets/NiCo2O4 nanowires hierarchical nanocomposite catalyst with surface rich high valence metal oxide as an efficient catalyst for oxygen evolution reaction. A low overpotential of 310 mV is needed to drive a 10 mA cm-2 with a Tafel slope of 99 mV dec-1, and a remarkable stability during 8 h is demonstrated in a chronoamperometry test. Theoretical calculation displays the change in the rate-determining step on the nanocomposite electrode in comparison to NiCo2O4 nanowires alone. It is found high valence Ni and Mn oxide in the catalyst system can efficiently facilitate the charge transport across the electrode/electrolyte interface. The enhanced electrical conductivity, more accessible active sites and synergistic effects between NiMn layered double hydroxide nanosheets and NiCo2O4 nanowires can account for the excellent oxygen evolution reaction. The catalytic performance is comparable to most of the best non-noble catalysts and IrO2 noble catalyst, indicating the promising applications in water-splitting technology. It is an important step in the development of hierarchical nanocomposites by surface valence state tuning as an alternative to noble metals for oxygen evolution reaction.

Protective Role of Aldose Reductase Deletion in an Animal Model of Oxygen-Induced Retinopathy

Directory of Open Access Journals (Sweden)

Zhongjie Fu

2011-05-01

Full Text Available Retinopathy of prematurity (ROP is a common disease occurred in premature babies. Both vascular abnormality and neural dysfunction of the retina were reported, and oxidative stress was involved. Previously, it has been showed that deficiency of aldose reductase (AR, the rate-limiting enzyme in polyol pathway, lowered oxidative stress. Here, the effect of AR deletion on neonatal retinal injury was investigated by using a mouse model of ROP (oxygen-induced retinopathy, OIR. Seven-day-old pups were exposed to 75% oxygen for 5 days and then returned to room air. The vascular changes and neuronal/glial responses were examined and compared between wild-type and AR-deficient OIR mice. Significantly reduced vaso-obliterated area, blood vessel leakage, and early revascularization were observed in AR-deficient OIR mice. Moreover, reduced amacrine cells and less distorted strata were observed in AR-deficient OIR mice. Less astrocytic immunoreactivity and reduced Müller cell gliosis were also observed in AR-deficient mice. After OIR, nitrotyrosine immunoreactivity and poly (ADP-ribose (PAR translocation, which are two oxidative stress markers, were decreased in AR-deficient mice. Significant decrease in VEGF, pho-Erk1/2, pho-Akt, and pho-I?B expression was found in AR-deficient OIR retinae. Thus, these observations suggest that the deficiency of aldose reductase may protect the retina in the OIR model.

Peculiarities of the free radical processes in rat liver mitochondria under toxic hepatitis on the background of alimentary protein deficiency

Directory of Open Access Journals (Sweden)

G. P. Kopylchuk

2016-04-01

Full Text Available The rate of superoxide anion radical, hydroxyl radical and hydrogen peroxide generation, the level of oxidative modification of mitochondrial proteins in the liver of rats with toxic hepatitis was investigated on the background of alimentary protein deficiency. We did not find significant increases of the intensity of free radical processes in liver mitochondria of rats maintained on the protein-deficient ration. The most significant intensification of free radical processes in liver mitochondria is observed under the conditions of toxic hepatitis, induced on the background of alimentary protein deprivation. Under these conditions the aggravation of all studied forms of reactive oxygen species generation was observed in liver mitochondria. The generation rates were increased as follows: O2 – by 1.7 times, Н2О2 – by 1.5 times, •ОН – practically double on the background of accumulation of oxidized mitochondria-derived proteins. The established changes in thiol groups’ redox status of respiratory chain proteins insoluble in 0.05 M sodium-phosphate buffer (pH 11.5, and changes of their carbonyl derivatives content may be considered as one of the regulatory factors of mitochondrial energy-generating function.

Thickness independent reduced forming voltage in oxygen engineered HfO{sub 2} based resistive switching memories

Energy Technology Data Exchange (ETDEWEB)

Sharath, S. U., E-mail: sharath@oxide.tu-darmstadt.de; Kurian, J.; Komissinskiy, P.; Hildebrandt, E.; Alff, L. [Institute of Materials Science, Technische Universität Darmstadt, 64287 Darmstadt (Germany); Bertaud, T.; Walczyk, C.; Calka, P. [IHP, Im Technologiepark 25, 15236 Frankfurt Oder (Germany); Schroeder, T. [IHP, Im Technologiepark 25, 15236 Frankfurt Oder (Germany); Brandenburgische Technische Universität, Konrad-Zuse-Strasse 1, 03046 Cottbus (Germany)

2014-08-18

The conducting filament forming voltage of stoichiometric hafnium oxide based resistive switching layers increases linearly with layer thickness. Using strongly reduced oxygen deficient hafnium oxide thin films grown on polycrystalline TiN/Si(001) substrates, the thickness dependence of the forming voltage is strongly suppressed. Instead, an almost constant forming voltage of about 3 V is observed up to 200 nm layer thickness. This effect suggests that filament formation and switching occurs for all samples in an oxidized HfO{sub 2} surface layer of a few nanometer thickness while the highly oxygen deficient thin film itself merely serves as a oxygen vacancy reservoir.

prevalence of iron deficiency in children with cyanotic heart disease

African Journals Online (AJOL)

2009-12-01

Dec 1, 2009 ... ... bone marrow to produce more red cells in an effort to increase the body's oxygen ... so the production of more and more red cells goes unabated leading to ... of iron deficiency was calculated as proportion of children with ...

The relationship between tumor oxygenation and cell proliferation in human soft tissue sarcomas

International Nuclear Information System (INIS)

Nordsmark, Marianne; Hoeyer, Morten; Keller, Johnny; Nielsen, Ole Steen; Jensen, Oluf Myhre; Overgaard, Jens

1996-01-01

Purpose: In malignant tumors the oxygenation status and tumor cell proliferation are known to influence local tumor control after radiotherapy. However, the relationship between oxygenation status and tumor cell kinetics in human tumors has not yet been described. Newly developed clinically applicable techniques such as oxygen electrode measurements and assessment of tumor cell proliferation rates have been suggested as promising predictive assays. The purpose of the present study was to characterize tumor oxygenation status in soft tissue sarcomas and to compare this with tumor cell kinetics and clinical parameters. Methods and Materials: Pretreatment tumor oxygenation status was measured by polarographic oxygen needle electrodes and evaluated as the median pO 2 and the percentage of pO 2 values ≤ 5 mmHg and ≤ 2.5 mmHg in 22 patients with primary soft tissue sarcomas. All tumors were characterized by histology, grade of malignancy, the level of microscopic necrosis, the level of effective hemoglobin, and magnetic resonance imaging estimation of tumor volume. The tumor cell potential doubling time and labeling index were measured by flow cytometric and immunohistochemical analysis of tumor biopsy specimens after in vivo incorporation of iododeoxyuridine. Results: There was a significant correlation between the median pO 2 and the tumor cell potential doubling time (p = 0.041), whereas no correlation was found between the level of hypoxia expressed by the percentage of pO 2 values ≤ 2.5 and ≤ 5 mmHg, respectively, and tumor cell potential doubling time. Furthermore, no correlation was found between either of the three tumor oxygenation parameters and labeling index. The material represented large intertumor heterogeneity in oxygenation status, cell kinetics, and tumor volume, and no correlation was found between oxygenation status and either volume, histopathology, grade of malignancy, or effective hemoglobin. Conclusion: This report is the first to suggest

Oxygen Dependent Biocatalytic Processes

DEFF Research Database (Denmark)

Pedersen, Asbjørn Toftgaard

Enzyme catalysts have the potential to improve both the process economics and the environ-mental profile of many oxidation reactions especially in the fine- and specialty-chemical industry, due to their exquisite ability to perform stereo-, regio- and chemo-selective oxida-tions at ambient...... to aldehydes and ketones, oxyfunctionalization of C-H bonds, and epoxidation of C-C double bonds. Although oxygen dependent biocatalysis offers many possibilities, there are numerous chal-lenges to be overcome before an enzyme can be implemented in an industrial process. These challenges requires the combined...... far below their potential maximum catalytic rate at industrially relevant oxygen concentrations. Detailed knowledge of the en-zyme kinetics are therefore required in order to determine the best operating conditions and design oxygen supply to minimize processing costs. This is enabled...

Fatty acid binding protein 4 deficiency protects against oxygen-induced retinopathy in mice.

Directory of Open Access Journals (Sweden)

Magali Saint-Geniez

Full Text Available Retinopathy of prematurity (ROP is a leading cause of blindness in children worldwide due to increasing survival rates of premature infants. Initial suppression, followed by increased production of the retinal vascular endothelial growth factor-A (VEGF expression are key events that trigger the pathological neovascularization in ROP. Fatty acid binding protein 4 (FABP4 is an intracellular lipid chaperone that is induced by VEGF in a subset of endothelial cells. FABP4 exhibits a pro-angiogenic function in cultured endothelial cells and in airway microvasculature, but whether it plays a role in modulation of retinal angiogenesis is not known. We hypothesized that FABP4 deficiency could ameliorate pathological retinal vascularization and investigated this hypothesis using a well-characterized mouse model of oxygen-induced retinopathy (OIR. We found that FABP4 was not expressed in retinal vessels, but was present in resident macrophages/microglial cells and endothelial cells of the hyaloid vasculature in the immature retina. While FABP4 expression was not required for normal development of retinal vessels, FABP4 expression was upregulated and localized to neovascular tufts in OIR. FABP4-/- mice demonstrated a significant decrease in neovessel formation as well as a significant improvement in physiological revascularization of the avascular retinal tissues. These alterations in retinal vasculature were accompanied by reduced endothelial cell proliferation, but no effect on apoptosis or macrophage/microglia recruitment. FABP4-/- OIR samples demonstrated decreased expression of genes involved in angiogenesis, such as Placental Growth Factor, and angiopoietin 2. Collectively, our findings suggest FABP4 as a potential target of pathologic retinal angiogenesis in proliferative retinopathies.

Aerobic Microbial Respiration In Oceanic Oxygen Minimum Zones

DEFF Research Database (Denmark)

Kalvelage, Tim; Lavik, Gaute; Jensen, Marlene Mark

2015-01-01

Namibia and Peru. Experiments with additions of double-labelled oxygen revealed high aerobic activity in the upper OMZs, likely controlled by surface organic matter export. Consistently observed oxygen consumption in samples retrieved throughout the lower OMZs hints at efficient exploitation of vertically...... and laterally advected, oxygenated waters in this zone by aerobic microorganisms. In accordance, metagenomic and metatranscriptomic analyses identified genes encoding for aerobic terminal oxidases and demonstrated their expression by diverse microbial communities, even in virtually anoxic waters. Our results...

Ordered oxygen deficient '112' perovskites, LnBaCo2 : complex ...

Indian Academy of Sciences (India)

Administrator

are labeled on the graph. .... in agreement with Kanamori Goodenough rules. In sum- mary, these results ... exhibit very rich phase diagrams as illustrated in figure 9. The latter .... which make that the control of oxygen content in these phases is ...

Chiral Aminophosphines as Catalysts for Enantioselective Double-Michael Indoline Syntheses

Directory of Open Access Journals (Sweden)

Ohyun Kwon

2012-05-01

Full Text Available The bisphosphine-catalyzed double-Michael addition of dinucleophiles to electron-deficient acetylenes is an efficient process for the synthesis of many nitrogen-containing heterocycles. Because the resulting heterocycles contain at least one stereogenic center, this double-Michael reaction would be even more useful if an asymmetric variant of the reaction were to be developed. Aminophosphines can also facilitate the double-Michael reaction and chiral amines are more readily available in Nature and synthetically; therefore, in this study we prepared several new chiral aminophosphines. When employed in the asymmetric double-Michael reaction between ortho-tosylamidophenyl malonate and 3-butyn-2-one, the chiral aminophosphines produced indolines in excellent yields with moderate asymmetric induction.

Oxygen transport in waterlogged soils, Part I. Approaches to modelling soil and crop response to oxygen deficiency

International Nuclear Information System (INIS)

Obando Moncayo, F.H.

2004-01-01

This lecture outlines in a simple way the mathematics of various cases of diffusion which have been widely used in modelling soil aeration. Simplifications of the general equation of diffusion (Fick's law) giving two possible forms of the problem: planar or one-dimensional diffusion and radial diffusion are given. Furthermore, the solution of diffusion equation is obtained by the analogy to the problem of electrical flow (Ohm's law). Taking into consideration the soil respiration process, the continuity equation which accounts for the law of conservation of mass is solved. The purpose of this paper has been to review the interrelation soil structure-air movement in waterlogged clay soils, and its consequences on plant growth and crop production. Thus, the mathematics of diffusion is presented, and then its application to specific cases of soil aeration such as diffusion in the soil profile, soil aggregates and roots is given. The following assumptions are taken into consideration. Gas flow in soils is basically diffusion-dependent. Gas-phase diffusion is the major mechanism for vertical or longitudinal transport (long distance transport); this means, with depth Z in the soil profile (macro diffusion). For horizontal transport (short distance transport or micro diffusion) which is assumed to be in X direction; in this case, the geometry of aggregates and the liquid phase are the major components of resistance for diffusion. Soil aggregates and roots are considered to be spherical and cylindrical in shape respectively. Soil oxygen consumption, Sr, is taken to be independent of the oxygen concentration and considered to proceed at the same rate until oxygen supply drops to critical levels. Thus, aeration problems are assumed to begin when at any time, in the root zone, the oxygen diffusion rate, ODR, becomes less than 30x10 -8 g.cm -2 .sec -1 , or the value of redox potential Eh is less than +525 mv

Opposing effects of CXCR3 and CCR5 deficiency on CD8+ T cell-mediated inflammation in the central nervous system of virus-infected mice

DEFF Research Database (Denmark)

de Lemos, Carina; Christensen, Jeanette Erbo; Nansen, Anneline

2005-01-01

and therefore protect mice against the otherwise fatal CD8+ T cell-mediated immune attack. Contrary to expectations, the accumulation of mononuclear cells in cerebrospinal fluid was only slightly delayed compared with mice with normal expression of both receptors. Even more surprising, CXCR3/CCR5 double-deficient......T cells play a key role in the control of viral infection in the CNS but may also contribute to immune-mediated cell damage. To study the redundancy of the chemokine receptors CXCR3 and CCR5 in regulating virus-induced CD8+ T cell-mediated inflammation in the brain, CXCR3/CCR5 double-deficient mice...... mice were more susceptible to intracerebral infection than CXCR3-deficient mice. Analysis of effector T cell generation revealed an accelerated antiviral CD8+ T cell response in CXCR3/CCR5 double-deficient mice. Furthermore, while the accumulation of CD8+ T cells in the neural parenchyma...

Equimolar mixture of nitroux oxyde and oxygen during post-operative physiotherapy in patients with cerebral palsy: A randomized, double-blind, placebo-controlled study.

Science.gov (United States)

Delafontaine, A; Presedo, A; Mohamed, D; Lopes, D; Wood, C; Alberti, C

2017-11-01

The administration of an equimolar mixture of nitrous oxide and oxygen (N2O) is recommended during painful procedures. However, the evaluation of its use during physiotherapy after surgery has not been reported, although pain may hamper physiotherapy efficiency. This study investigated whether the use of N2O improves the efficacy of post-operative physiotherapy after multilevel surgery in patients with cerebral palsy. It was a randomized 1:1, double-blind, placebo-controlled study. All patients had post-operative physiotherapy starting the day after surgery. Patients received either N2O or placebo gas during the rehabilitation sessions. All patients had post-operative pain management protocol, including pain medication as needed for acute pain. The primary objective was to reach angles of knee flexion of 110° combined with hip extension of 10°, with the patient lying prone, within six or less physiotherapy sessions. Secondary evaluation criteria were the number of sessions required to reach the targeted angles, the session-related pain intensity and the analgesics consumption for managing post-operative pain. Sixty-four patients were enrolled. Targeted angles were achieved more often in the N2O group (23 of 32, 72%, vs. Placebo: 13/ of 32, 41%; p = 0.01). The administration of N2O during post-operative physiotherapy can help to achieve more quickly an improved range of motion, and, although not significant in our study, to alleviate the need for pain medication. Further studies evaluating the administration of N2O in various settings are warranted. During this randomized placebo-controlled double-blind study, children receiving nitrous oxide and oxygen (N2O) achieved more often the targeted range of motion during physiotherapy sessions after multilevel surgery. Compared to placebo, nitrous oxide and oxygen (N2O) enabled a better management of acute pain related to physiotherapy procedures. © 2017 European Pain Federation - EFIC®.

Evidence for induction of DNA double strand breaks in the bystander response to targeted soft X-rays in repair deficient CHO cells

International Nuclear Information System (INIS)

Kashino, Genro; Suzuki, Keiji; Prise, K.M.

2005-01-01

Evidence is accumulating that irradiated cells produce some signals which interact with non-exposed cells in the same population. Here, we analysed the mechanism of such a bystander effect from targeted cells to non-targeted cells. Firstly, in order to investigate the bystander effect in Chinese hamster ovary (CHO) cell lines we irradiated a single cell within a population and scored the formation of micronuclei. When a single nucleus in the population, of double strand break repair deficient xrs5 cells, was targeted with 1 Gy of Al-K soft X-rays, elevated numbers of micronuclei were induced in the neighbouring unirradiated cells. The induction of micronuclei was also observed when conditioned medium was transferred from irradiated to non-irradiated xrs5 cells. These results suggest that DNA double strand breaks are caused by factors secreted in the medium from irradiated cells. To clarify the involvements of radical species in the bystander response, cells were treated with 0.5%DMSO 1 hour before irradiation and then bystander effects were estimated in xrs5 cells. The results showed clearly that DMSO treatment during X-irradiation suppress the induction of micronuclei in bystander xrs5 cells, when conditioned medium was transferred from irradiated xrs5 cells. Therefore, it is suggested that radical species induced by ionizing radiation are important for producing bystander signals. (author)

Deficiency of double-strand DNA break repair does not impair Mycobacterium tuberculosis virulence in multiple animal models of infection.

Science.gov (United States)

Heaton, Brook E; Barkan, Daniel; Bongiorno, Paola; Karakousis, Petros C; Glickman, Michael S

2014-08-01

Mycobacterium tuberculosis persistence within its human host requires mechanisms to resist the effector molecules of host immunity, which exert their bactericidal effects through damaging pathogen proteins, membranes, and DNA. Substantial evidence indicates that bacterial pathogens, including M. tuberculosis, require DNA repair systems to repair the DNA damage inflicted by the host during infection, but the role of double-strand DNA break (DSB) repair systems is unclear. Double-strand DNA breaks are the most cytotoxic form of DNA damage and must be repaired for chromosome replication to proceed. M. tuberculosis elaborates three genetically distinct DSB repair systems: homologous recombination (HR), nonhomologous end joining (NHEJ), and single-strand annealing (SSA). NHEJ, which repairs DSBs in quiescent cells, may be particularly relevant to M. tuberculosis latency. However, very little information is available about the phenotype of DSB repair-deficient M. tuberculosis in animal models of infection. Here we tested M. tuberculosis strains lacking NHEJ (a Δku ΔligD strain), HR (a ΔrecA strain), or both (a ΔrecA Δku strain) in C57BL/6J mice, C3HeB/FeJ mice, guinea pigs, and a mouse hollow-fiber model of infection. We found no difference in bacterial load, histopathology, or host mortality between wild-type and DSB repair mutant strains in any model of infection. These results suggest that the animal models tested do not inflict DSBs on the mycobacterial chromosome, that other repair pathways can compensate for the loss of NHEJ and HR, or that DSB repair is not required for M. tuberculosis pathogenesis. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Denitrifying bacterial community composition changes associated with stages of denitrification in oxygen minimum zones

Digital Repository Service at National Institute of Oceanography (India)

Jayakumar, D.A; O'Mullan, G.D.; Naqvi, S.W.A.; Ward, B.B.

in the ocean. Nature 445:163–167 11. Devol AH (1978) Bacterial oxygen uptake kinetics as related to biological processes in oxygen deficient zones of the oceans. Deep-Sea Res 25:137–146 12. Devol AH, Uhlenhopp AG, Naqvi SWA, Brandes JA, Jayakumar DA, Naik H...

Measurement of oxygen thermomigration in a hypostoichiometric mixed oxide

International Nuclear Information System (INIS)

Norris, D.I.R.; Coleman, S.C.; Kay, P.

1978-08-01

A method of determining oxygen to metal ratios in hypostoichiometric (U, Ce)Osub(2-x) by means of lattice parameter measurement and its application to thermomigration experiments is described. The technique is shown to compare favourably with other methods when a simple structure prevails. It is found that oxygen redistributes down an imposed temperature gradient, confirming theoretical predictions, and that the measured Arrhenius slope decreases as the cerium valency decreases. This effect is more marked than in (U, Pu)Osub(2-x). The results are attributable to solid state transport of oxygen vacancies and suggest that immobile complexes incorporating some oxygen deficiency are more easily formed in (U, Ce)Osub(2-x) than in (U, Pu)Osub(2-x). (author)

Crystal structure and surface characteristics of Sr-doped GdBaCo2O6−δ double perovskites: oxygen evolution reaction and conductivity

KAUST Repository

Pramana, Stevin S.

2017-12-04

A cheap and direct solution towards engineering better catalysts through identification of novel materials is required for a sustainable energy system. Perovskite oxides have emerged as potential candidates to replace the less economically attractive Pt and IrO2 water splitting catalysts. In this work, excellent electrical conductivity (980 S cm−1) was found for the double perovskite of composition GdBa0.6Sr0.4Co2O6−δ which is consistent with a better oxygen evolution reaction activity with the onset polarisation of 1.51 V with respect to a reversible hydrogen electrode (RHE). GdBa1−xSrxCo2O6−δ with increasing Sr content was found to crystallise in the higher symmetry tetragonal P4/mmm space group in comparison with the undoped GdBaCo2O6−δ which is orthorhombic (Pmmm), and yields higher oxygen uptake, accompanied by higher Co oxidation states. This outstanding electrochemical performance is explained by the wider carrier bandwidth, which is a function of Co–O–Co buckling angles and Co–O bond lengths. Furthermore the higher oxygen evolution activity was observed despite the formation of non-lattice oxides (mainly hydroxide species) and enrichment of alkaline earth ions on the surface.

Crystal structure and surface characteristics of Sr-doped GdBaCo2O6−δ double perovskites: oxygen evolution reaction and conductivity

KAUST Repository

Pramana, Stevin S.; Cavallaro, Andrea; Li, Cheng; Handoko, Albertus D.; Chan, Kuang Wen; Walker, Robert J.; Regoutz, Anna; Herrin, Jason S.; Yeo, Boon Siang; Payne, David J.; Kilner, John A.; Ryan, Mary P.; Skinner, Stephen J.

2017-01-01

A cheap and direct solution towards engineering better catalysts through identification of novel materials is required for a sustainable energy system. Perovskite oxides have emerged as potential candidates to replace the less economically attractive Pt and IrO2 water splitting catalysts. In this work, excellent electrical conductivity (980 S cm−1) was found for the double perovskite of composition GdBa0.6Sr0.4Co2O6−δ which is consistent with a better oxygen evolution reaction activity with the onset polarisation of 1.51 V with respect to a reversible hydrogen electrode (RHE). GdBa1−xSrxCo2O6−δ with increasing Sr content was found to crystallise in the higher symmetry tetragonal P4/mmm space group in comparison with the undoped GdBaCo2O6−δ which is orthorhombic (Pmmm), and yields higher oxygen uptake, accompanied by higher Co oxidation states. This outstanding electrochemical performance is explained by the wider carrier bandwidth, which is a function of Co–O–Co buckling angles and Co–O bond lengths. Furthermore the higher oxygen evolution activity was observed despite the formation of non-lattice oxides (mainly hydroxide species) and enrichment of alkaline earth ions on the surface.

[Deficient lactose digestion and intolerance in a group of patients with chronic nonspecific ulcerative colitis: a controlled, double-blind, cross-over clinical trial].

Science.gov (United States)

Cabrera-Acosta, G A; Milke-García, M P; Ramírez-Iglesias, M T; Uscanga, L

2012-01-01

Despite the fact that the frequency of hypolactasia and lactose intolerance is similar in both chronic idiopathic ulcerative colitis patients and the general population, the elimination of dairy products from the patient's diet is a habitual recommendation. Hypolactasia is common in Mexico, but its relation to chronic idiopathic ulcerative colitis has not been established. To evaluate lactose digestion and lactose intolerance in persons with chronic idiopathic ulcerative colitis. Thirty-nine patients with confirmed chronic idiopathic ulcerative colitis diagnosis were included in the study (mean: 31 years, range: 15 to 38). Twenty-two patients presented with rectosigmoid involvement and the remaining patients with pancolitis. No patient showed inflammatory activity according to the Truelove-Witts criteria and all consumed dairy products before diagnosis. A prospective, controlled, double-blind, cross-over study was designed. Patients randomly received 12.5 g of lactose or maltose in 250 cc water- each test 72 hours apart - and ydrogen was measured in exhaled air before disaccharide ingestion and then every 30 minutes for 3 hours. Digestion was considered deficient when there was an increase in hydrogen of at least 20 ppm. Symptom intensities were evaluated by Visual Analog Scales before, during, and after the hydrogen test. Differences between the groups were contrasted with the Mann-Whitney U and the Wilcoxon tests. Eighteen patients (46%) presented with deficient lactose digestion. No significant differences were found in the symptoms, extension, or progression of chronic idiopathic ulcerative colitis between patients that could digest and those that could not digest lactose. No patient had symptom exacerbation with the disaccharides used. Lactose digestion deficiency frequency is similar in subjects with chronic idiopathic ulcerative colitis and in healthy individuals in Mexico. We do not know whether higher doses could have some effect, but symptoms in patients

Hydrogen-deficient Central Stars of Planetary Nebulae

Science.gov (United States)

Todt, H.; Kniazev, A. Y.; Gvaramadze, V. V.; Hamann, W.-R.; Pena, M.; Graefener, G.; Buckley, D.; Crause, L.; Crawford, S. M.; Gulbis, A. A. S.; Hettlage, C.; Hooper, E.; Husser, T.-O.; Kotze, P.; Loaring, N.; Nordsieck, K. H.; O'Donoghue, D.; Pickering, T.; Potter, S.; Romero-Colmenero, E.; Vaisanen, P.; Williams, T.; Wolf, M.

2015-06-01

A significant number of the central stars of planetary nebulae (CSPNe) are hydrogen-deficient and are considered as the progenitors of H-deficient white dwarfs. Almost all of these H-deficient CSPNe show a chemical composition of helium, carbon, and oxygen. Most of them exhibit Wolf-Rayet-like emission line spectra and are therefore classified as of spectral type [WC]. In the last years, CSPNe of other Wolf-Rayet spectral subtypes have been identified, namely PB 8 (spectral type [WN/WC]), IC 4663 and Abell 48 (spectral type [WN]). We performed spectral analyses for a number of Wolf-Rayet type central stars of different evolutionary stages with the help of our Potsdam Wolf-Rayet (PoWR) model code for expanding atmospheres to determine relevant stellar parameters. The results of our recent analyses will be presented in the context of stellar evolution and white dwarf formation. Especially the problems of a uniform evolutionary channel for [WC] stars as well as constraints to the formation of [WN] or [WN/WC] subtype stars will be addressed.

Impact of oxygen-depleted water on the vertical distribution of chaetognaths in the northeastern Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

Kusum, K.K.; Vineetha, G.; Raveendran, T.V.; Muraleedharan, K.R.; Nair, M.; Achuthankutty, C.T.

The influence of a thick layer of oxygen-depleted water (<0.2 ml l sup(-1)) on the abundance and distribution of chaetognaths was investigated in the northeastern Arabian Sea (NEAS), a natural oxygen-deficient system in the global ocean. The species...

High-temperature equilibrium study of the oxygen-site occupancy in YBa2Cu3O7-δ by positron annihilation

International Nuclear Information System (INIS)

Hermes, H.; Forster, M.; Schaefer, H.

1991-01-01

Measurements of the positron lifetime and the Doppler broadening of the annihilation γ line were performed on sintered YBa 2 Cu 3 O 7-δ specimens between ambient temperature and 1140 K at oxygen partial pressures, p O2 , between 10 2 and 10 5 Pa in order to study the atomic processes of changes of the oxygen content in thermal equilibrium. Above 680 K the positron lifetime increases with increasing temperature and decreasing oxygen partial pressure. It is found that the normalized positron annihilation rate λ 1 * depends exclusively on the oxygen deficiency δ and decreases linearly with increasing δ. Our results demonstrate that the positrons are annihilated predominantly on the sites of the Cu(1)-O(1) chains where the oxygen atoms are removed (oxygen-deficient sites), as suggested by theoretical studies. A simple atomistic model of oxygen exchange is confirmed by the experimentally observed variation of the positron annihilation rate with (p O2 ) -0.27

Comparison of Langmuir probe and multipole resonance probe measurements in argon, hydrogen, nitrogen, and oxygen mixtures in a double ICP discharge

Science.gov (United States)

Fiebrandt, Marcel; Oberberg, Moritz; Awakowicz, Peter

2017-07-01

The results of a Multipole Resonance Probe (MRP) are compared to a Langmuir probe in measuring the electron density in Ar, H2, N2, and O2 mixtures. The MRP was designed for measurements in industry processes, i.e., coating or etching. To evaluate a possible influence on the MRP measurement due to molecular gases, different plasmas with increasing molecular gas content in a double inductively coupled plasma at 5 Pa and 10 Pa at 500 W are used. The determined electron densities from the MRP and the Langmuir probe slightly differ in H2 and N2 diluted argon plasmas, but diverge significantly with oxygen. In pure molecular gas plasmas, electron densities measured with the MRP are always higher than those measured with the Langmuir Probe, in particular, in oxygen containing mixtures. The differences can be attributed to etching of the tungsten wire in the Ar:O2 mixtures and rf distortion in the pure molecular discharges. The influence of a non-Maxwellian electron energy distribution function, negative ions or secondary electron emission seems to be of no or only minor importance.

Effect of oxygen treatment on heart rate after abdominal surgery

DEFF Research Database (Denmark)

Rosenberg-Adamsen, S; Lie, C; Bernhard, A

1999-01-01

BACKGROUND: Cardiac complications are common during the postoperative period and may be associated with hypoxemia and tachycardia. Preliminary studies in high-risk patients after operation have shown a possible beneficial effect of oxygen therapy on arterial oxygen saturation and heart rate....... METHODS: The authors studied the effect of oxygen therapy on arterial oxygen saturation and heart rate in 100 consecutive unselected patients randomly and double blindly allocated to receive air or oxygen therapy between the first and fourth day after major abdominal surgery. RESULTS: The median arterial...... oxygen saturation rate increased significantly from 96% to 99% (P heart rate decreased significantly from 85 beats/min to 81 beats/min (P heart rate occurred...

Cathepsin E deficiency impairs autophagic proteolysis in macrophages.

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Takayuki Tsukuba

Full Text Available Cathepsin E is an endosomal aspartic proteinase that is predominantly expressed in immune-related cells. Recently, we showed that macrophages derived from cathepsin E-deficient (CatE(-/- mice display accumulation of lysosomal membrane proteins and abnormal membrane trafficking. In this study, we demonstrated that CatE(-/- macrophages exhibit abnormalities in autophagy, a bulk degradation system for aggregated proteins and damaged organelles. CatE(-/- macrophages showed increased accumulation of autophagy marker proteins such as LC3 and p62, and polyubiquitinated proteins. Cathepsin E deficiency also altered autophagy-related signaling pathways such as those mediated by the mammalian target of rapamycin (mTOR, Akt, and extracellular signal-related kinase (ERK. Furthermore, immunofluorescence microscopy analyses showed that LC3-positive vesicles were merged with acidic compartments in wild-type macrophages, but not in CatE(-/- macrophages, indicating inhibition of fusion of autophagosome with lysosomes in CatE(-/- cells. Delayed degradation of LC3 protein was also observed under starvation-induced conditions. Since the autophagy system is involved in the degradation of damaged mitochondria, we examined the accumulation of damaged mitochondria in CatE(-/- macrophages. Several mitochondrial abnormalities such as decreased intracellular ATP levels, depolarized mitochondrial membrane potential, and decreased mitochondrial oxygen consumption were observed. Such mitochondrial dysfunction likely led to the accompanying oxidative stress. In fact, CatE(-/- macrophages showed increased reactive oxygen species (ROS production and up-regulation of oxidized peroxiredoxin-6, but decreased antioxidant glutathione. These results indicate that cathepsin E deficiency causes autophagy impairment concomitantly with increased aberrant mitochondria as well as increased oxidative stress.

Interaction of oxygen vacancies in yttrium germanates

KAUST Repository

Wang, Hao

2012-01-01

Forming a good Ge/dielectric interface is important to improve the electron mobility of a Ge metal oxide semiconductor field-effect transistor. A thin yttrium germanate capping layer can improve the properties of the Ge/GeO 2 system. We employ electronic structure calculations to investigate the effect of oxygen vacancies in yttrium-doped GeO 2 and the yttrium germanates Y 2Ge 2O 7 and Y 2GeO 5. The calculated densities of states indicate that dangling bonds from oxygen vacancies introduce in-gap states, but the system remains insulating. However, yttrium-doped GeO 2 becomes metallic under oxygen deficiency. Y-doped GeO 2, Y 2Ge 2O 7 and Y 2GeO 5 are calculated to be oxygen substoichiometric under low Fermi energy conditions. The use of yttrium germanates is proposed as a way to effectively passivate the Ge/dielectric interface. This journal is © 2012 the Owner Societies.

Effectiveness of anode in a solid oxide fuel cell with hydrogen/oxygen mixed gases

Energy Technology Data Exchange (ETDEWEB)

Kellogg, Isaiah D. [Department of Mechanical and Aerospace Engineering, Missouri University of Science and Technology, Rolla, MO (United States); Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO (United States); Koylu, Umit O. [Department of Mechanical and Aerospace Engineering, Missouri University of Science and Technology, Rolla, MO (United States); Petrovsky, Vladimir; Dogan, Fatih [Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO (United States)

2009-06-15

A porous Ni/YSZ cermet in mixed hydrogen and oxygen was investigated for its ability to decrease oxygen activity as the anode of a single chamber SOFC. A cell with a dense 300 {mu}m YSZ electrolyte was operated in a double chamber configuration. The Ni-YSZ anode was exposed to a mixture of hydrogen and oxygen of varying compositions while the cathode was exposed to oxygen. Double chamber tests with mixed gas on the anode revealed voltage oscillations linked to lowered power generation and increased resistance. Resistance measurements of the anode during operation revealed a Ni/NiO redox cycle causing the voltage oscillations. The results of these tests, and future tests of similar format, could be useful in the development of single chamber SOFC using hydrogen as fuel. (author)

Diamine oxidase (DAO) supplement reduces headache in episodic migraine patients with DAO deficiency: A randomized double-blind trial.

Science.gov (United States)

Izquierdo-Casas, Joan; Comas-Basté, Oriol; Latorre-Moratalla, M Luz; Lorente-Gascón, Marian; Duelo, Adriana; Soler-Singla, Luis; Vidal-Carou, M Carmen

2018-02-15

Histamine intolerance is a disorder in the homeostasis of histamine due to a reduced intestinal degradation of this amine, mainly caused by a deficiency in the enzyme diamine oxidase (DAO). Among histamine related symptoms, headache is one of the most recorded. Current clinical strategies for the treatment of the symptomatology related to this disorder are based on the exclusion of foods with histamine or other bioactive amines and/or exogenous DAO supplementation. The aim of this study was to assess the efficacy of a food supplement consisting of DAO enzyme as a preventive treatment of migraine in patients with DAO deficiency through a randomized double-blind trial. 100 patients with confirmed episodic migraine according to current International Headache Society (IHS) criteria and DAO deficiency (levels below 80 HDU/ml) were randomized in two groups. One group received DAO enzyme supplementation and the other received placebo for one month. Clinical outcomes assessed were duration and number of attacks, perception of pain intensity and adverse effects during treatment. The use of triptans was also recorded. Great variability was found in the duration of migraine attacks reported by placebo and DAO groups. A significant reduction (p = 0.0217) in hours of pain was achieved in patients treated with DAO supplement, with mean durations of 6.14 (±3.06) and 4.76 (±2.68) hours before and after treatment, respectively. A smaller reduction without statistical signification was also observed for this outcome in the placebo group, from 7.53 (±4.24) to 6.68 (±4.42) hours. Only in DAO group, a decrease in the percentage of patients taking triptans was observed. The number of attacks and the scores of pain intensity showed a similar reduction in both groups. No adverse effects were registered in patients treated with DAO enzyme. Migrainous patients supplemented with DAO enzyme during one month significantly reduced the duration of their migraine attacks by 1.4 h. No

Controlled oxygen vacancy induced p-type conductivity in HfO{sub 2-x} thin films

Energy Technology Data Exchange (ETDEWEB)

Hildebrandt, Erwin; Kurian, Jose; Mueller, Mathis M.; Kleebe, Hans-Joachim; Alff, Lambert [Institute of Materials Science, Technische Universitaet Darmstadt, 64287 Darmstadt (Germany); Schroeder, Thomas [IHP, 15236 Frankfurt/Oder (Germany)

2011-09-12

We have synthesized highly oxygen deficient HfO{sub 2-x} thin films by controlled oxygen engineering using reactive molecular beam epitaxy. Above a threshold value of oxygen vacancies, p-type conductivity sets in with up to 6 times 10{sup 21} charge carriers per cm{sup 3}. At the same time, the band-gap is reduced continuously by more than 1 eV. We suggest an oxygen vacancy induced p-type defect band as origin of the observed behavior.

CXCL14 deficiency in mice attenuates obesity and inhibits feeding behavior in a novel environment.

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Kosuke Tanegashima

Full Text Available BACKGROUND: CXCL14 is a chemoattractant for macrophages and immature dendritic cells. We recently reported that CXCL14-deficient (CXCL14(-/- female mice in the mixed background are protected from obesity-induced hyperglycemia and insulin resistance. The decreased macrophage infiltration into visceral adipose tissues and the increased insulin sensitivity of skeletal muscle contributed to these phenotypes. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we performed a comprehensive study for the body weight control of CXCL14(-/- mice in the C57BL/6 background. We show that both male and female CXCL14(-/- mice have a 7-11% lower body weight compared to CXCL14(+/- and CXCL14(+/+ mice in adulthood. This is mainly caused by decreased food intake, and not by increased energy expenditure or locomotor activity. Reduced body weight resulting from the CXCL14 deficiency was more pronounced in double mutant CXCL14(-/-ob/ob and CXCL14(-/-A(y mice. In the case of CXCL14(-/-A(y mice, oxygen consumption was increased compared to CXCL14(+/-A(y mice, in addition to the reduced food intake. In CXCL14(-/- mice, fasting-induced up-regulation of Npy and Agrp mRNAs in the hypothalamus was blunted. As intracerebroventricular injection of recombinant CXCL14 did not change the food intake of CXCL14(-/- mice, CXCL14 could indirectly regulate appetite. Intriguingly, the food intake of CXCL14(-/- mice was significantly repressed when mice were transferred to a novel environment. CONCLUSIONS/SIGNIFICANCE: We demonstrated that CXCL14 is involved in the body weight control leading to the fully obese phenotype in leptin-deficient or A(y mutant mice. In addition, we obtained evidence indicating that CXCL14 may play an important role in central nervous system regulation of feeding behavior.

Circadian behaviour in neuroglobin deficient mice.

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Christian A Hundahl

Full Text Available Neuroglobin (Ngb, a neuron-specific oxygen-binding globin with an unknown function, has been proposed to play a key role in neuronal survival. We have previously shown Ngb to be highly expressed in the rat suprachiasmatic nucleus (SCN. The present study addresses the effect of Ngb deficiency on circadian behavior. Ngb-deficient and wild-type (wt mice were placed in running wheels and their activity rhythms, endogenous period and response to light stimuli were investigated. The effect of Ngb deficiency on the expression of Period1 (Per1 and the immediate early gene Fos was determined after light stimulation at night and the neurochemical phenotype of Ngb expressing neurons in wt mice was characterized. Loss of Ngb function had no effect on overall circadian entrainment, but resulted in a significantly larger phase delay of circadian rhythm upon light stimulation at early night. A light-induced increase in Per1, but not Fos, gene expression was observed in Ngb-deficient mice. Ngb expressing neurons which co-stored Gastrin Releasing Peptide (GRP and were innervated from the eye and the geniculo-hypothalamic tract expressed FOS after light stimulation. No PER1 expression was observed in Ngb-positive neurons. The present study demonstrates for the first time that the genetic elimination of Ngb does not affect core clock function but evokes an increased behavioural response to light concomitant with increased Per1 gene expression in the SCN at early night.

A double-leg donor-acceptor molecular elevator: new insight into controlling the distance of two platforms.

Science.gov (United States)

Zhang, Zhi-Jun; Han, Min; Zhang, Heng-Yi; Liu, Yu

2013-04-05

A double-leg elevator with an electron-rich anthracene moiety at the platformlike component and an electron-deficient naphthalenediimide unit in the middle of a double-leg riglike component was prepared through "click chemistry", in which the reversible elevator movement between different levels could be controlled upon the addition of base and acid.

Double white dwarfs as progenitors of R coronae borealis stars and type I supernovae

International Nuclear Information System (INIS)

Webbink, R.F.

1984-01-01

Close double white dwarfs should arise from the second phase of mass exchagne in close binaries which first encountered mass exchange while the more massive star was crossing the Hertzprung gap. Tidal mass transfer in these double degenerate systems is explored. The sequence of double white dwarf divides naturally into three segments. (1) Low-mass helium/helium pairs are unstable to dynamical time-scale mass transfer and probably coalesce to form helium-burning sdO stars. (2) In helium/carbon-oxygen pairs, mass transfer occurs on the time scale for gravitational radiation losses (approx.10 -4 M/sub sun/ yr -1 ); the accreted helium is quickly ignited, and the accretor expands to dimensions characteristic of R CrB stars, engulfing its companion star. (3) Carbon-oxygen/carbon-oxygen pairs are again unstable to dynamical time-scale mass transfer and, since their total masses exceed the Chandrasekhar limit, are destined to become supernovae. Inactive lifetimes in these latter systems between creation and interaction can exceed 10 10 years. Birthrates of R CrB stars and Type I supernovae by evolution of double white dwarfs are in reasonable agreement with observational estimates

Biogeochemical cycling of iron and phosphorus under low oxygen conditions

OpenAIRE

Lomnitz, Ulrike

2017-01-01

Benthic release of the key nutrients iron (Fe) and phosphorus (P) is enhanced from sediments that are impinged by oxygen-deficient bottom waters due to its diminished retention capacity for such redox sensitive elements. Suboxic to anoxic and sometimes even euxinic conditions are recently found in open ocean oxygen minimum zones (OMZs, e.g. Eastern Boundary Upwelling Systems) and marginal seas (e.g. the Black Sea and the Baltic Sea). Recent studies showed that OMZs expanded in the last decade...

Enhanced activity of CaFeMg layered double hydroxides-supported gold nanodendrites for the electrochemical evolution of oxygen and hydrogen in alkaline media

Science.gov (United States)

Havakeshian, Elaheh; Salavati, Hossein; Taei, Masoumeh; Hasheminasab, Fatemeh; Seddighi, Mohadeseh

2018-02-01

In this study, Au was electrodeposited on a support of CaFeMg layered double hydroxide and then, its catalytic activity was investigated for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Field emission scanning electron microscopy images showed that a uniform porous film of aggregated nano-particles of the LDH has been decorated with Au nanodendrite-like structures (AuNDs@LDH). The results obtained from polarization curves, Tafel plots and electrochemical impedance spectroscopy showed that the AuNDs@LDH exhibits lower overpotential, higher current density, faster kinetics and enhanced stability for both of the OER and HER, in comparison with the single AuNPs and LDH catalysts.

[Extracorporeal membrane oxygenation in primary graft dysfunction in a paediatric double lung transplant: presentation of a case].

Science.gov (United States)

López-Cantero, M; Grisolía, A L; Vicente, R; Moreno, I; Ramos, F; Porta, J; Torregrosa, S

2014-04-01

Primary graft dysfunction is a leading cause of morbimortality in the immediate postoperative period of patients undergoing lung transplantation. Among the treatment options are: lung protective ventilatory strategies, nitric oxide, lung surfactant therapy, and supportive treatment with extracorporeal membrane oxygenation (ECMO) as a bridge to recovery of lung function or re-transplant. We report the case of a 9-year-old girl affected by cystic fibrosis who underwent double-lung transplantation complicated with a severe primary graft dysfunction in the immediate postoperative period and refractory to standard therapies. Due to development of multiple organ failure, it was decided to insert arteriovenous ECMO catheters (pulmonary artery-right atrium). The postoperative course was satisfactory, allowing withdrawal of ECMO on the 5th post-surgical day. Currently the patient survives free of rejection and with an excellent quality of life after 600 days of follow up. Copyright © 2012 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Published by Elsevier España. All rights reserved.

Mechanisms of radiosensitization and protection studied with glutathione-deficient human cell lines

International Nuclear Information System (INIS)

Revesz, L.; Edgren, M.

1982-01-01

Glutathione-deficient fibroblasts and lymphoblastoid cells, derived from patients with an inborn error of glutathione synthetase activity, and glutathione-proficient cells, derived from clinically healthy individuals, were used to investigate the importance of glutathione for radiosensitization by misonidazole. With single-strand DNA breaks as an end point, misonidazole as well as oxygen was found to lack any sensitizing effect on cells deficient in glutathione. The post-irradiation repair of single-strand breaks induced by hypoxic irradiation of misonidazole treated cells was found to be a great extent glutathione dependent, like the repair of breaks induced by oxic irradiation. Naturally occurring aminothiols in glutathione-deficient cells appeared to be in efficient as substitutes for glutatione. Artificial aminothiols, such as cysteamine or dithiothreitol, were found to effectively replace glutathione

Excess Oxygen Defects in Layered Cuprates

Science.gov (United States)

Lightfoot, P.; Pei, S. Y.; Jorgensen, J. D.; Manthiram, A.; Tang, X. X.; Goodenough, J. B.

1990-09-01

Neutron powder diffraction has been used to study the oxygen defect chemistry of two non-superconducting layered cuprates, La{sub 1. 25}Dy{sub 0.75}Cu{sub 3.75}F{sub 0.5}, having a T{sup {asterisk}}- related structure, and La{sub 1.85}Sr{sub 1.15}Cu{sub 2}O{sub 6.25}, having a structure related to that of the newly discovered double-layer superconductor La{sub 2-x}Sr{sub x}CaCu{sub 2}O{sub 6}. The role played by oxygen defects in determining the superconducting properties of layered cuprates is discussed.

Formation and Migration of Oxygen Vacancies in SrCoO3 and their effect on Oxygen Evolution Reactions

KAUST Repository

Tahini, Hassan A.; Tan, Xin; Schwingenschlö gl, Udo; Smith, Sean C.

2016-01-01

Perovskite SrCoO3 is a potentially useful material for promoting the electrocatalytic oxygen evolution reaction, with high activities predicted theoretically and observed experimentally for closely related doped perovskite materials. However, complete stoichiometric oxidation is very difficult to realize experimentally – in almost all cases there are significant fractions of oxygen vacancies present. Here, using first principles calculations we study oxygen vacancies in perovskite SrCoO3 from thermodynamic, electronic and kinetic points of view. We find that an oxygen vacancy donates two electrons to neighboring Co sites in the form of localized charge. The formation energy of a single vacancy is very low and estimated to be 1.26 eV in the dilute limit. We find that a vacancy is quite mobile with a migration energy of ~0.5 eV. Moreover, we predict that oxygen vacancies exhibit a tendency towards clustering which is in accordance with the material’s ability to form a variety of oxygen-deficient structures. These vacancies have a profound effect on the material’s ability to facilitate OER, increasing the overpotential from ~0.3 V for the perfect material to ~0.7 for defective surfaces. A moderate compressive biaxial strain (2%) is predicted here to increase the surface oxygen vacancy formation energy by ca. 30%, thus reducing the concentration of surface vacancies and thereby preserving the OER activity of the material.

Formation and Migration of Oxygen Vacancies in SrCoO3 and their effect on Oxygen Evolution Reactions

KAUST Repository

Tahini, Hassan A.

2016-07-18

Perovskite SrCoO3 is a potentially useful material for promoting the electrocatalytic oxygen evolution reaction, with high activities predicted theoretically and observed experimentally for closely related doped perovskite materials. However, complete stoichiometric oxidation is very difficult to realize experimentally – in almost all cases there are significant fractions of oxygen vacancies present. Here, using first principles calculations we study oxygen vacancies in perovskite SrCoO3 from thermodynamic, electronic and kinetic points of view. We find that an oxygen vacancy donates two electrons to neighboring Co sites in the form of localized charge. The formation energy of a single vacancy is very low and estimated to be 1.26 eV in the dilute limit. We find that a vacancy is quite mobile with a migration energy of ~0.5 eV. Moreover, we predict that oxygen vacancies exhibit a tendency towards clustering which is in accordance with the material’s ability to form a variety of oxygen-deficient structures. These vacancies have a profound effect on the material’s ability to facilitate OER, increasing the overpotential from ~0.3 V for the perfect material to ~0.7 for defective surfaces. A moderate compressive biaxial strain (2%) is predicted here to increase the surface oxygen vacancy formation energy by ca. 30%, thus reducing the concentration of surface vacancies and thereby preserving the OER activity of the material.

Diminished exercise capacity and mitochondrial bc1 complex deficiency in tafazzin-knockdown mice.

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Corey ePowers

2013-04-01

Full Text Available The phospholipid, cardiolipin, is essential for maintaining mitochondrial structure and optimal function. Cardiolipin-deficiency in humans, Barth syndrome, is characterized by exercise intolerance, dilated cardiomyopathy, neutropenia and 3-methyl-glutaconic aciduria. The causative gene is the mitochondrial acyl-transferase, tafazzin that is essential for remodeling acyl chains of cardiolipin. We sought to determine metabolic rates in tafazzin-deficient mice during resting and exercise, and investigate the impact of cardiolipin deficiency on mitochondrial respiratory chain activities. Tafazzin knockdown in mice markedly impaired oxygen consumption rates during an exercise, without any significant effect on resting metabolic rates. CL-deficiency resulted in significant reduction of mitochondrial respiratory reserve capacity in neonatal cardiomyocytes that is likely to be caused by diminished activity of complex-III, which requires CL for its assembly and optimal activity. Our results may provide mechanistic insights of Barth syndrome pathogenesis.

Glucose-6-phosphate dehydrogenase deficiency in Nigerian children.

Directory of Open Access Journals (Sweden)

Olatundun Williams

Full Text Available Glucose-6-phosphate dehydrogenase (G6PD deficiency is the most common human enzymopathy and in Sub-Saharan Africa, is a significant cause of infection- and drug-induced hemolysis and neonatal jaundice. Our goals were to determine the prevalence of G6PD deficiency among Nigerian children of different ethnic backgrounds and to identify predictors of G6PD deficiency by analyzing vital signs and hematocrit and by asking screening questions about symptoms of hemolysis. We studied 1,122 children (561 males and 561 females aged 1 month to 15 years. The mean age was 7.4 ± 3.2 years. Children of Yoruba ethnicity made up the largest group (77.5% followed by those Igbo descent (10.6% and those of Igede (10.2% and Tiv (1.8% ethnicity. G6PD status was determined using the fluorescent spot method. We found that the overall prevalence of G6PD deficiency was 15.3% (24.1% in males, 6.6% in females. Yoruba children had a higher prevalence (16.9% than Igede (10.5%, Igbo (10.1% and Tiv (5.0% children. The odds of G6PD deficiency were 0.38 times as high in Igbo children compared to Yoruba children (p=0.0500. The odds for Igede and Tiv children were not significantly different from Yoruba children (p=0.7528 and 0.9789 respectively. Mean oxygen saturation, heart rate and hematocrit were not significantly different in G6PD deficient and G6PD sufficient children. The odds of being G6PD deficient were 2.1 times higher in children with scleral icterus than those without (p=0.0351. In conclusion, we determined the prevalence of G6PD deficiency in Nigerian sub-populations. The odds of G6PD deficiency were decreased in Igbo children compared to Yoruba children. There was no association between vital parameters or hematocrit and G6PD deficiency. We found that a history of scleral icterus may increase the odds of G6PD deficiency, but we did not exclude other common causes of icterus such as sickle cell disease or malarial infection.

Iron Deficiency Prolongs Seed Dormancy in Arabidopsis Plants

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Irene Murgia

2017-12-01

Full Text Available The understanding of seed dormancy, germination and longevity are important goals in plant biology, with relevant applications for agriculture, food industry and also human nutrition. Reactive Oxygen Species (ROS are key molecules involved in the release of dormancy, when their concentrations fall within the so called ‘oxidative window.’ The mechanisms of ROS distribution and sensing in seeds, from dormant to germinating ones, still need elucidation. Also, the impact of iron (Fe deficiency on seed dormancy is still unexplored; this is surprising, given the known pro-oxidant role of Fe when in a free form. We provide evidence of a link between plant Fe nutrition and dormancy of progeny seeds by using different Arabidopsis ecotypes and mutants with different dormancy strengths grown in control soil or under severe Fe deficiency. The latter condition extends the dormancy in several genotypes. The focus on the mechanisms involved in the Fe deficiency-dependent alteration of dormancy and longevity promises to be a key issue in seed (redox biology.

A link between double-strand break-related repair and V(D)J recombination: the scid mutation

International Nuclear Information System (INIS)

Hendrickson, E.A.; Qin, X.Q.; Bump, E.A.; Schatz, D.G.; Oettinger, M.; Weaver, D.T.

1991-01-01

We show here that mammalian site-specific recombination and DNA-repair pathways share a common factor. The effects of DNA-damaging agents on cell lines derived from mice homozygous for the scid (severe combined immune deficiency) mutation were studied. Surprisingly, all scid cell lines exhibited a profound hypersensitivity to DNA-damaging agents that caused double-strand breaks (x-irradiation and bleomycin) but not to other chemicals that caused single-strand breaks or cross-links. Neutral filter elution assays demonstrated that the x-irradiation hypersensitivity could be correlated with a deficiency in repairing double-strand breaks. These data suggest that the scid gene product is involved in two pathways: DNA repair of random double-strand breaks and the site-specific and lymphoid-restricted variable-(diversity)-joining [V(D)J] DNA rearrangement process. We propose that the scid gene product performs a similar function in both pathways and may be a ubiquitous protein

Study of oxygen inhibition effect on radiation curing

International Nuclear Information System (INIS)

Xiao Bin; Yang Xuemei; Zhao Pengji; Zeng Shuqing; Jiang Bo; Zhou Yong; Huang Wei; Zhou Youyi

1995-01-01

Michacl addition reaction product was used in the research of oxygen inhibition effect of radiation curing. The experimental results was measured by the content of gel and percentage of double bonds. It was proved that 9% of Michacl addition product could speed up 1.2 times of the radiation curing rate at 30 kGy of EB irradiation. This kind of formulation can withstand oxygen inhibition effect obviously, so it was the foundation of application for radiation curing in atmospheric condition

THE OXYGEN REGIME OF A SHALLOW LAKE

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Galina Zdorovennova

2016-01-01

Full Text Available The year-round measurement data of water temperature and dissolved oxygen content in a small boreal Lake Vendyurskoe in 2007–2013 were used to explore the hydrophysical prerequisits of anoxia and accumulation and emission of greenhouse gases. Typically, anoxia appears in the bottom layers of lakes in mid-winter and during the summer  stagnation. The thickness of the benthic anaerobic zone (dissolved oxygen concentration <2 mg·l–1 reached one meter in the end of the winter and at the peak of the summer stratification, except for the extremely hot summer of 2010, when it reached five meters. Synoptic conditions had a crucial influence on the formation and destruction of the benthic anaerobic zones in summer. The most favorable oxygen dynamics was observed during the cold summers of 2008, 2009, and 2012, when the repeated full mixings of the water column occurred under conditions of the cyclonic weather. In the winter periods, the early dates of ice season resulted in the most pronounced deficiency of oxygen.

Enhanced response to radiotherapy in tumours deficient in the function of hypoxia-inducible factor-1

International Nuclear Information System (INIS)

Williams, Kaye J.; Telfer, Brian A.; Xenaki, Dia; Sheridan, Mary R.; Desbaillets, Isabelle; Peters, Hans J.W.; Honess, Davina; Harris, Adrian L.; Dachs, Gabi U.; Kogel, Albert van der; Stratford, Ian J.

2005-01-01

Background and purpose: To test the hypothesis that deficiency in expression of the transcription factor, HIF-1, renders tumours more radioresponsive than HIF-1 proficient tumours. Patients and methods: Tumours comprising mouse hepatoma cells lacking HIF-1β (and thereby HIF-1 function) were grown in nude mice and radiation-induced growth delay compared with that seen for wild-type tumours and tumours derived from HIF-1β negative cells where HIF-1 function had been restored. Results: The xenografts that lack HIF-1 activity take longer to establish their growth and are more radioresponsive than both parental xenografts and those with restored HIF-1 function. Pre-treatment of the HIF-1 deficient xenografts with the hypoxic radiosensitizer misonidazole, had little effect on radioresponse. In contrast this treatment radiosensitized the parental xenografts. In spite of this, no difference in oxygenation status was found between the tumour types as measured by Eppendorf O 2 -electrodes and by binding of the hypoxic cell marker NITP. Admixing wild type and HIF-1 deficient cells in the same tumour at ratios of 1 in 10 and 1 in 100 restores the growth of the mixed tumours to that of a 100% HIF-1 proficient cell population. However, when comparing the effects of radiation on the mixed tumours, radioresponsiveness is maintained in those tumours containing the high proportion of HIF-1 deficient cells. Conclusions: The differences in radioresponse do not correlate with tumour oxygenation, suggesting that the hypoxic cells within the HIF-1 deficient tumours do not contribute to the outcome of radiotherapy. Thus, hypoxia impacts on tumour radioresponsiveness not simply because of the physio-chemical mechanism of oxygen with radiation-induced radicals causing damage 'fixation', but also because hypoxia/HIF-1 promotes expression of genes that allow tumour cells to survive under these adverse conditions. Further, the results from the cell mixing experiments uncouple the growth

Storage Pool Deficiencies

Science.gov (United States)

... Deficiency Factor V Deficiency Combined FV & FVIII Deficiencies Factor VII Deficiency Factor X Deficiency Factor XI Deficiency Factor ... Deficiency Factor V Deficiency Combined FV & FVIII Deficiencies Factor VII Deficiency Factor X Deficiency Factor XI Deficiency Factor ...

Oxygen engineering of HfO{sub 2-x} thin films grown by reactive molecular beam epitaxy

Energy Technology Data Exchange (ETDEWEB)

Hildebrandt, Erwin; Kurian, Jose; Alff, Lambert [Institut fuer Materialwissenschaft, TU-Darmstadt (Germany); Zaumseil, Peter; Schroeder, Thomas [IHP, Frankfurt, Oder (Germany)

2010-07-01

Reactive molecular beam epitaxy (R-MBE) is an ideal tool for tailoring physical properties of thin films to specific needs. For the development of cutting-edge oxides for thin film applications a precise control of oxygen defects is crucial. R-MBE in combination with rf-activated oxygen allows reproducibly growing oxide thin films with precise oxidation conditions enabling oxygen engineering. R-MBE was used to grow Hf and HfO{sub 2{+-}}{sub x} thin films with different oxidation conditions on sapphire single crystal substrates. Structural characterization was carried out using rotating anode x-ray diffraction revealing highly textured to epitaxial thin films on c-cut sapphire. Furthermore, switching of film orientation by varying the oxidation conditions was observed demonstrating the role of oxygen in the growth procedure. The investigation of electrical properties using a four probe measurement setup showed conductivities in the range of 1000 {mu}{omega}cm for oxygen deficient HfO{sub 2-x} thin films. Optical properties were investigated using a photospectrometer and additionally x-ray photoelectron spectroscopy was carried out to study the band gap and valence states. Both techniques were used to monitor the oxygen content in deficient HfO{sub 2-x} thin films. Our results demonstrate the importance of oxygen engineering even in the case of 'simple' oxides.

Sensitization to radiation and alkylating agents by inhibitors of poly(ADP-ribose) polymerase is enhanced in cells deficient in DNA double-strand break repair.

Science.gov (United States)

Löser, Dana A; Shibata, Atsushi; Shibata, Akiko K; Woodbine, Lisa J; Jeggo, Penny A; Chalmers, Anthony J

2010-06-01

As single agents, chemical inhibitors of poly(ADP-ribose) polymerase (PARP) are nontoxic and have clinical efficacy against BRCA1- and BRCA2-deficient tumors. PARP inhibitors also enhance the cytotoxicity of ionizing radiation and alkylating agents but will only improve clinical outcomes if tumor sensitization exceeds effects on normal tissues. It is unclear how tumor DNA repair proficiency affects the degree of sensitization. We have previously shown that the radiosensitizing effect of PARP inhibition requires DNA replication and will therefore affect rapidly proliferating tumors more than normal tissues. Because many tumors exhibit defective DNA repair, we investigated the impact of double-strand break (DSB) repair integrity on the sensitizing effects of the PARP inhibitor olaparib. Sensitization to ionizing radiation and the alkylating agent methylmethane sulfonate was enhanced in DSB repair-deficient cells. In Artemis(-/-) and ATM(-/-) mouse embryo fibroblasts, sensitization was replication dependent and associated with defective repair of replication-associated damage. Radiosensitization of Ligase IV(-/-) mouse embryo fibroblasts was independent of DNA replication and is explained by inhibition of "alternative" end joining. After methylmethane sulfonate treatment, PARP inhibition promoted replication-independent accumulation of DSB, repair of which required Ligase IV. Our findings predict that the sensitizing effects of PARP inhibitors will be more pronounced in rapidly dividing and/or DNA repair defective tumors than normal tissues and show their potential to enhance the therapeutic ratio achieved by conventional DNA-damaging agents.

MSH3-deficiency initiates EMAST without oncogenic transformation of human colon epithelial cells.

Directory of Open Access Journals (Sweden)

Christoph Campregher

Full Text Available BACKGROUND/AIM: Elevated microsatellite instability at selected tetranucleotide repeats (EMAST is a genetic signature in certain cases of sporadic colorectal cancer and has been linked to MSH3-deficiency. It is currently controversial whether EMAST is associated with oncogenic properties in humans, specifically as cancer development in Msh3-deficient mice is not enhanced. However, a mutator phenotype is different between species as the genetic positions of repetitive sequences are not conserved. Here we studied the molecular effects of human MSH3-deficiency. METHODS: HCT116 and HCT116+chr3 (both MSH3-deficient and primary human colon epithelial cells (HCEC, MSH3-wildtype were stably transfected with an EGFP-based reporter plasmid for the detection of frameshift mutations within an [AAAG]17 repeat. MSH3 was silenced by shRNA and changes in protein expression were analyzed by shotgun proteomics. Colony forming assay was used to determine oncogenic transformation and double strand breaks (DSBs were assessed by Comet assay. RESULTS: Despite differential MLH1 expression, both HCT116 and HCT116+chr3 cells displayed comparable high mutation rates (about 4×10(-4 at [AAAG]17 repeats. Silencing of MSH3 in HCECs leads to a remarkable increased frameshift mutations in [AAAG]17 repeats whereas [CA]13 repeats were less affected. Upon MSH3-silencing, significant changes in the expression of 202 proteins were detected. Pathway analysis revealed overexpression of proteins involved in double strand break repair (MRE11 and RAD50, apoptosis, L1 recycling, and repression of proteins involved in metabolism, tRNA aminoacylation, and gene expression. MSH3-silencing did not induce oncogenic transformation and DSBs increased 2-fold. CONCLUSIONS: MSH3-deficiency in human colon epithelial cells results in EMAST, formation of DSBs and significant changes of the proteome but lacks oncogenic transformation. Thus, MSH3-deficiency alone is unlikely to drive human colon

Double-outlet right ventricle revisited.

Science.gov (United States)

Ebadi, Ameneh; Spicer, Diane E; Backer, Carl L; Fricker, F Jay; Anderson, Robert H

2017-08-01

Double-outlet right ventricle is a form of ventriculoarterial connection. The definition formulated by the International Society for Nomenclature of Paediatric and Congenital Heart Disease is based on hearts with both arterial trunks supported in their greater part by a morphologically right ventricle. Bilateral infundibula and ventricular septal defects are highly debated criteria. This study examines the anatomic controversies surrounding double-outlet right ventricle. We show that hearts with double-outlet right ventricle can have atrioventricular-to-arterial valvular continuity. We emphasize the difference between the interventricular communication and the zone of deficient ventricular septation. The hearts examined were from the University of Florida in Gainesville; Johns Hopkins All Children's Hospital, St Petersburg, Fla; and Lurie Children's Hospital, Chicago, Ill. Each specimen had at least 75% of both arterial roots supported by the morphologically right ventricle, with a total of 100 hearts examined. The morphologic method was used to assess anatomic features, including arterial-atrioventricular valvular continuity, subarterial infundibular musculature, and the location of the hole between the ventricles. Most hearts had fibrous continuity between one of the arterial valves and an atrioventricular valve, with bilateral infundibula in 23%, and intact ventricular septum in 5%. Bilateral infundibula are not a defining feature of double-outlet right ventricle, representing only 23% of the specimens in our sample. The interventricular communication can have a posteroinferior muscular rim or extend to become perimembranous (58%). Double-outlet right ventricle can exist with an intact ventricular septum. Copyright © 2017 The American Association for Thoracic Surgery. All rights reserved.

Fanconi anemia links reactive oxygen species to insulin resistance and obesity.

Science.gov (United States)

Li, Jie; Sipple, Jared; Maynard, Suzette; Mehta, Parinda A; Rose, Susan R; Davies, Stella M; Pang, Qishen

2012-10-15

Insulin resistance is a hallmark of obesity and type 2 diabetes. Reactive oxygen species (ROS) have been proposed to play a causal role in insulin resistance. However, evidence linking ROS to insulin resistance in disease settings has been scant. Since both oxidative stress and diabetes have been observed in patients with the Fanconi anemia (FA), we sought to investigate the link between ROS and insulin resistance in this unique disease model. Mice deficient for the Fanconi anemia complementation group A (Fanca) or Fanconi anemia complementation group C (Fancc) gene seem to be diabetes-prone, as manifested by significant hyperglycemia and hyperinsulinemia, and rapid weight gain when fed with a high-fat diet. These phenotypic features of insulin resistance are characterized by two critical events in insulin signaling: a reduction in tyrosine phosphorylation of the insulin receptor (IR) and an increase in inhibitory serine phosphorylation of the IR substrate-1 in the liver, muscle, and fat tissues from the insulin-challenged FA mice. High levels of ROS, spontaneously accumulated or generated by tumor necrosis factor alpha in these insulin-sensitive tissues of FA mice, were shown to underlie the FA insulin resistance. Treatment of FA mice with the natural anti-oxidant Quercetin restores IR signaling and ameliorates the diabetes- and obesity-prone phenotypes. Finally, pairwise screen identifies protein-tyrosine phosphatase (PTP)-α and stress kinase double-stranded RNA-dependent protein kinase (PKR) that mediate the ROS effect on FA insulin resistance. These findings establish a pathogenic and mechanistic link between ROS and insulin resistance in a unique human disease setting. ROS accumulation contributes to the insulin resistance in FA deficiency by targeting both PTP-α and PKR.

STS-84 oxygen generator for Mir installation

Science.gov (United States)

1997-01-01

In the SPACEHAB Payload Processing Facility, McDonnell Douglas- SPACEHAB technicians prepare a Russian-made oxygen generator for flight in a SPACEHAB Double Module. The oxygen generator, manufactured in Russia by RSC Energia, will be carried aboard the Space Shuttle Atlantis on Mission STS-84 for the Shuttles scheduled docking with the Russian Space Station Mir next month. The nearly 300-pound generator will replace one of two Mir units that have been malfunctioning recently. The generator functions by electrolysis, which separates water into its oxygen and hydrogen components. The hydrogen is vented and the oxygen is used for breathing by the Mir crew. The generator is 4.2 feet in length and 1.4 feet in diameter. STS-84, which is planned to include a Mir crew exchange of astronaut C. Michael Foale for Jerry M. Linenger, is targeted for a May 15 liftoff. It will be the sixth Shuttle-Mir docking.

Facilitated Oxygen Chemisorption in Heteroatom-Doped Carbon for Improved Oxygen Reaction Activity in All-Solid-State Zinc-Air Batteries.

Science.gov (United States)

Liu, Sisi; Wang, Mengfan; Sun, Xinyi; Xu, Na; Liu, Jie; Wang, Yuzhou; Qian, Tao; Yan, Chenglin

2018-01-01

Driven by the intensified demand for energy storage systems with high-power density and safety, all-solid-state zinc-air batteries have drawn extensive attention. However, the electrocatalyst active sites and the underlying mechanisms occurring in zinc-air batteries remain confusing due to the lack of in situ analytical techniques. In this work, the in situ observations, including X-ray diffraction and Raman spectroscopy, of a heteroatom-doped carbon air cathode are reported, in which the chemisorption of oxygen molecules and oxygen-containing intermediates on the carbon material can be facilitated by the electron deficiency caused by heteroatom doping, thus improving the oxygen reaction activity for zinc-air batteries. As expected, solid-state zinc-air batteries equipped with such air cathodes exhibit superior reversibility and durability. This work thus provides a profound understanding of the reaction principles of heteroatom-doped carbon materials in zinc-air batteries. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Leg oxygen uptake in the initial phase of intense exercise is slowed by a marked reduction in oxygen delivery

DEFF Research Database (Denmark)

Christensen, Peter Møller; Nyberg, Michael Permin; Mortensen, Stefan Peter

2013-01-01

-extensor exercise (60±3 W) for 4 min in a control setting (CON) and with arterial infusion of L-NMMA and indomethacin in the working leg to reduce blood flow by inhibiting formation of nitric oxide and prostanoids (double blockade; DB). In DB leg blood flow (LBF) and oxygen delivery during the first minute...

PTP1B controls non-mitochondrial oxygen consumption by regulating RNF213 to promote tumour survival during hypoxia.

Science.gov (United States)

Banh, Robert S; Iorio, Caterina; Marcotte, Richard; Xu, Yang; Cojocari, Dan; Rahman, Anas Abdel; Pawling, Judy; Zhang, Wei; Sinha, Ankit; Rose, Christopher M; Isasa, Marta; Zhang, Shuang; Wu, Ronald; Virtanen, Carl; Hitomi, Toshiaki; Habu, Toshiyuki; Sidhu, Sachdev S; Koizumi, Akio; Wilkins, Sarah E; Kislinger, Thomas; Gygi, Steven P; Schofield, Christopher J; Dennis, James W; Wouters, Bradly G; Neel, Benjamin G

2016-07-01

Tumours exist in a hypoxic microenvironment and must limit excessive oxygen consumption. Hypoxia-inducible factor (HIF) controls mitochondrial oxygen consumption, but how/if tumours regulate non-mitochondrial oxygen consumption (NMOC) is unknown. Protein-tyrosine phosphatase-1B (PTP1B) is required for Her2/Neu-driven breast cancer (BC) in mice, although the underlying mechanism and human relevance remain unclear. We found that PTP1B-deficient HER2(+) xenografts have increased hypoxia, necrosis and impaired growth. In vitro, PTP1B deficiency sensitizes HER2(+) BC lines to hypoxia by increasing NMOC by α-KG-dependent dioxygenases (α-KGDDs). The moyamoya disease gene product RNF213, an E3 ligase, is negatively regulated by PTP1B in HER2(+) BC cells. RNF213 knockdown reverses the effects of PTP1B deficiency on α-KGDDs, NMOC and hypoxia-induced death of HER2(+) BC cells, and partially restores tumorigenicity. We conclude that PTP1B acts via RNF213 to suppress α-KGDD activity and NMOC. This PTP1B/RNF213/α-KGDD pathway is critical for survival of HER2(+) BC, and possibly other malignancies, in the hypoxic tumour microenvironment.

Formation of neutrophil extracellular traps under low oxygen level

Directory of Open Access Journals (Sweden)

Katja Branitzki-Heinemann

2016-11-01

Full Text Available Since their discovery, neutrophil extracellular traps (NETs have been characterized as a fundamental host innate immune defense mechanism. Conversely, excessive NET release may have a variety of detrimental consequences for the host. A fine balance between NET formation and elimination is necessary to sustain a protective effect during an infectious challenge. Our own recently published data revealed that stabilization of hypoxia inducible factor 1α (HIF-1α by the iron chelating HIF-1α-agonist desferoxamine or AKB-4924 enhanced the release of phagocyte extracellular traps. Since HIF-1α is a global regulator of the cellular response to low oxygen, we hypothesized that NET formation may be similarly increased under low oxygen conditions. Hypoxia occurs in tissues during infection or inflammation, mostly due to overconsumption of oxygen by pathogens and recruited immune cells. Therefore, experiments were performed to characterize the formation of NETs under hypoxic oxygen conditions compared to normoxia. Human blood-derived neutrophils were isolated and incubated under normoxic (21% oxygen level and compared to hypoxic (1% conditions. Dissolved oxygen levels were monitored in the primary cell culture using a Fibox4-PSt3 measurement system. The formation of NETs was quantified by fluorescence microscopy in response to the known NET-inducer phorbol 12-myristate 13-acetate (PMA or S. aureus wildtype and a nuclease-deficient mutant. In contrast to our hypothesis, spontaneous NET formation of neutrophils incubated under hypoxia was distinctly reduced compared to control neutrophils incubated under normoxia. Furthermore, neutrophils incubated under hypoxia showed significantly reduced formation of NETs in response to PMA. Gene expression analysis revealed that mRNA level of hif-1α as well as hif-1α target genes was not altered. However, in good correlation to the decreased NET formation under hypoxia, the cholesterol content of the neutrophils was

Hyperbaric Oxygen Treatment of Chronic Refractory Radiation Proctitis: A Randomized and Controlled Double-Blind Crossover Trial With Long-Term Follow-Up

International Nuclear Information System (INIS)

Clarke, Richard E.; Tenorio, L. M. Catalina; Hussey, James R.; Toklu, Akin S.; Cone, D. Lindsie; Hinojosa, Jose G.; Desai, Samir P.; Dominguez Parra, Luis; Rodrigues, Sylvia D.; Long, Robert J.; Walker, Margaret B.

2008-01-01

Purpose: Cancer patients who undergo radiotherapy remain at life-long risk of radiation-induced injury to normal tissues. We conducted a randomized, controlled, double-blind crossover trial with long-term follow-up to evaluate the effectiveness of hyperbaric oxygen for refractory radiation proctitis. Methods and Materials: Patients with refractory radiation proctitis were randomized to hyperbaric oxygen at 2.0 atmospheres absolute (Group 1) or air at 1.1 atmospheres absolute (Group 2). The sham patients were subsequently crossed to Group 1. All patients were re-evaluated by an investigator who was unaware of the treatment allocation at 3 and 6 months and Years 1-5. The primary outcome measures were the late effects normal tissue-subjective, objective, management, analytic (SOMA-LENT) score and standardized clinical assessment. The secondary outcome was the change in quality of life. Results: Of 226 patients assessed, 150 were entered in the study and 120 were evaluable. After the initial allocation, the mean SOMA-LENT score improved in both groups. For Group 1, the mean was lower (p 0.0150) and the amount of improvement nearly twice as great (5.00 vs. 2.61, p = 0.0019). Similarly, Group 1 had a greater portion of responders per clinical assessment than did Group 2 (88.9% vs. 62.5%, respectively; p 0.0009). Significance improved when the data were analyzed from an intention to treat perspective (p = 0.0006). Group 1 had a better result in the quality of life bowel bother subscale. These differences were abolished after the crossover. Conclusion: Hyperbaric oxygen therapy significantly improved the healing responses in patients with refractory radiation proctitis, generating an absolute risk reduction of 32% (number needed to treat of 3) between the groups after the initial allocation. Other medical management requirements were discontinued, and advanced interventions were largely avoided. Enhanced bowel-specific quality of life resulted

Low blood flow at onset of moderate intensity exercise does not limit muscle oxygen uptake

DEFF Research Database (Denmark)

Nyberg, Michael Permin; Mortensen, Stefan Peter; Saltin, Bengt

2010-01-01

The effect of low blood flow at onset of moderate intensity exercise on the rate of rise in muscle oxygen uptake was examined. Seven male subjects performed a 3.5 minute one-legged knee-extensor exercise bout (24+/-1 (+/-S.D.) W) without (CON) and with (double blockade; DB) arterial infusion of i....... Additionally, prostanoids and/or NO appear to play important roles in elevating skeletal muscle blood flow in the initial phase of exercise. Key words: Oxygen delivery, oxygen extraction, nitric oxide, prostanoids.......The effect of low blood flow at onset of moderate intensity exercise on the rate of rise in muscle oxygen uptake was examined. Seven male subjects performed a 3.5 minute one-legged knee-extensor exercise bout (24+/-1 (+/-S.D.) W) without (CON) and with (double blockade; DB) arterial infusion...... of inhibitors of nitric oxide synthase (NOS; L-NMMA) and cyclooxygenase (COX; indomethacin) in order to inhibit the synthesis of nitric oxide (NO) and prostanoids, respectively.. Leg blood flow and leg oxygen delivery throughout exercise was 25-50 % lower (P

Processing and characterization of Sr2−xVMoO6−δ double perovskites

International Nuclear Information System (INIS)

Weisentein, A.J.; Childs, N.; Amendola, R.; Driscoll, D.; Sofie, S.W.; Gannon, P.; Smith, R.

2013-01-01

In this study, the analysis and characterization of the processing and sintering of Sr 2−x VMoO 6−δ perovskites, where x = 0.0, 0.1 and 0.2, was investigated with application potential in high temperature fuel cell electrodes and electro-catalysts. Sr 2−x VMoO 6−δ substrates were sintered in a reducing (5%H 2 95%N 2 ) atmosphere at 1100 °C, 1200 °C, and 1300 °C. The X-ray diffraction patterns indicate that the double perovskite is the primary phase for Sr 2−x VMoO 6−δ pellets sintered at 1200 °C and 1300 °C for 20 h; however, these pellets show a secondary phase of SrMoO 4−δ . X-ray photoelectron spectroscopy revealed a deficiency of vanadium on the pellet surfaces, in which samples yielded surface vanadium concentrations of less than 5%. The vanadium inhomogeneity can be explained by the formation of the SrMoO 4−δ scheelite phase (ABO 4 ) due to oxygen exposure on the surface of the pellets, which indicates inward vanadium migration to the bulk, and was exhibited in redox cycling. Sr 2−x VMoO 6−δ pellets sintered at 1300 °C showed the lowest resistivity at both SOFC operating temperature (800 °C) and room temperature. The resistivity tests also show a semiconductor to metallic transition for all double perovskites, from heating up to 800 °C to cooling down to room temperature in a reducing atmosphere, related to the reduction of Mo 6+ to Mo 4+ . - Highlights: ► Primary Sr 2−x VMoO 6−δ phase only shown to form in excess of 1300 °C in reducing. ► Surface formation of secondary phase SrMoO 4−δ (Mo 6+ ) observed at RT in air. ► Surface vanadium deficiency induced by inward atomic diffusion. ► Semiconductor to metallic transition is related to the reduction of Mo 6+ to Mo 4+

Oxygen dosing the surface of SrTiO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Dudy, L.; Scheiderer, P.; Schuetz, P.; Gabel, J.; Buchwald, M.; Sing, M.; Claessen, R. [Physikalisches Institut, Universitaet Wuerzburg (Germany); Denlinger, J.D. [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94270 (United States); Schlueter, C.; Lee, T.L. [Diamond Light Source Ltd., Didcot, Oxfordshire (United Kingdom)

2015-07-01

The highly mobile two-dimensional electron system (2DES) on the surface of the insulating SrTiO{sub 3}(STO) offers exciting perspectives for advanced material design. This 2DES resides in a depletion layer caused by oxygen deficiency of the surface. With photoemission spectroscopy, we monitor the appearance of quasi-particle weight (QP) at the Fermi energy and oxygen vacancy induced states in the band gap (IG). Both, QP and IG weight, increase and decrease respectively upon exposure to extreme ultraviolet (XUV) light and in-situ oxygen dosing. By a proper adjustment of oxygen dosing, any intermediate state can be stabilized providing full control over the charge carrier density. From a comparison of the charge carrier concentrations obtained from an analysis of core-level spectra and the Fermi-surface volume, we conclude on a spatially inhomogeneous surface electronic structure with at least two different phases.

Smoking before isometric exercise amplifies myocardial stress and dysregulates baroreceptor sensitivity and cerebral oxygenation.

Science.gov (United States)

Anyfanti, Panagiota; Triantafyllidou, Eleftheria; Papadopoulos, Stavros; Triantafyllou, Areti; Nikolaidis, Michalis G; Kyparos, Antonios; Vrabas, Ioannis S; Douma, Stella; Zafeiridis, Andreas; Dipla, Konstantina

2017-06-01

This crossover study examined whether acute cardiovascular responses, baroreceptor sensitivity (BRS), and brain oxygenation during isometric exercise are altered after cigarette smoking. Twelve young, habitual smokers randomly performed a smoking and a control protocol, during which participants smoked one cigarette (0.9 mg nicotine) or a sham cigarette, before exercise. Testing involved baseline, a 5-minute smoking, a 10-minute post-smoking rest, 3-minute handgrip exercise (30% maximum voluntary contraction), and recovery. Beat-to-beat blood pressure, heart rate (HR), and cerebral oxygenation (near infrared spectroscopy) were continuously monitored. Double-product, stroke volume (SV), cardiac output, systemic vascular resistance and BRS were assessed. During post-smoking rest, systolic or diastolic blood pressure (140.8 ± 12.1/87.0 ± 6.9 vs. 125.9 ± 7.1/77.3 ± 5.5 mm Hg), HR, and double product were higher in the smoking versus the control protocol, whereas BRS was lower (P exercise, smoking resulted in greater HR and double product (17,240 ± 3893 vs. 15,424 ± 3173 mm Hg·bpm) and lower BRS versus the control protocol (P smoking elicited a delayed return of brain oxygenation indices, lower BRS, and higher double product. Smoking a cigarette shortly before the exercise session amplifies myocardial stress and dysregulates autonomic function and cerebral oxygenation during exercise and recovery, even in young habitual smokers, perceived as free from long-term cardiovascular effects of smoking. Copyright © 2017 American Society of Hypertension. Published by Elsevier Inc. All rights reserved.

Oxygen amendment on growth and nitrogen-use efficiency of flooded Italian Basil

Science.gov (United States)

Flooding is a frequent and often unavoidable cause of stress, in vegetable production in Florida. Flooding results in hypoxia i.e., oxygen deficiency. This study was conducted with traditional Italian basil (Ocimum basilicum L.), cv. Genovese OG, treated with either a fast- or slow-release solid oxy...

First-principles study of oxygen evolution reaction on Co doped NiFe-layered double hydroxides

Science.gov (United States)

Yu, Jie; Perdew, John; Yan, Qimin

The conversion of solar energy to renewable fuels is a grand challenge. One of the crucial steps for this energy conversion process is the discovery of efficient catalysts with lower overpotential for the oxygen evolution reaction (OER). Layered double hydroxides (LDH) with earth abundant elements such as Ni and Fe have been found as promising OER catalysts and shown to be active for water oxidation. Doping is one of the feasible ways to even lower the overpotential of host materials and breaks the linear scaling law. In this talk we'll present our study on the reaction mechanism of OER on pure and Co-doped NiFe-LDH systems in alkaline solution. We study the absorption energetics of reaction intermediate states and calculate the thermodynamic reaction energy using density functional theory with the PBE +U and the newly developed SCAN functionals. It is shown that the NiFe-LDH system with Co dopants has lower overpotential and higher activity compared with the undoped system. The improvement in activity is related to the presence of Co states in the electronic structure. The work provides a clear clue for the further improvement of the OER activity of LDH systems by chemical doping. The work was supported as part of the Center for the Computational Design of Functional Layered Materials, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science.

Iodine Deficiency

Science.gov (United States)

... Fax/Phone Home » Iodine Deficiency Leer en Español Iodine Deficiency Iodine is an element that is needed ... world’s population remains at risk for iodine deficiency. Iodine Deficiency FAQs WHAT IS THE THYROID GLAND? The ...

Physical properties and band structure of reactive molecular beam epitaxy grown oxygen engineered HfO{sub 2{+-}x}

Energy Technology Data Exchange (ETDEWEB)

Hildebrandt, Erwin; Kurian, Jose; Alff, Lambert [Institute of Materials Science, Technische Universitaet Darmstadt, 64287 Darmstadt (Germany)

2012-12-01

We have conducted a detailed thin film growth structure of oxygen engineered monoclinic HfO{sub 2{+-}x} grown by reactive molecular beam epitaxy. The oxidation conditions induce a switching between (111) and (002) texture of hafnium oxide. The band gap of oxygen deficient hafnia decreases with increasing amount of oxygen vacancies by more than 1 eV. For high oxygen vacancy concentrations, defect bands form inside the band gap that induce optical transitions and p-type conductivity. The resistivity changes by several orders of magnitude as a function of oxidation conditions. Oxygen vacancies do not give rise to ferromagnetic behavior.

Repair of double-strand breaks in Micrococcus radiodurans

International Nuclear Information System (INIS)

Burrell, A.D.; Dean, C.J.

1975-01-01

Micrococcus radiodurans has been shown to sustain double-strand breaks in its DNA after exposure to x-radiation. Following sublethal doses of x-rays (200 krad in oxygen or less), the cells were able to repair these breaks, and an intermediate fast-sedimenting DNA component seemed to be involved in the repair process

Experimental evidence for anisotropic double exchange interaction driven anisotropic transport in manganite heterostructures

NARCIS (Netherlands)

Liao, Zhaoliang; Koster, Gertjan; Huijben, Mark; Rijnders, A.J.H.M.

2017-01-01

An anisotropic double exchange interaction driven giant transport anisotropy is demonstrated in a canonic double exchange system of La2/3Sr1/3MnO3 ultrathin films epitaxially grown on NdGaO3 (110) substrates. The oxygen octahedral coupling at the La2/3Sr1/3MnO3/NdGaO3 interface induces a planar

The oxygen effect in E. coli cells

International Nuclear Information System (INIS)

Myasnik, M.N.; Skvortsov, V.G.; Sokolov, V.A.

1982-01-01

In experiments on E. coli strains deficient in some stages of DNA repair from radiation damages, it was demonstrated that the value of the oxygen effect, under optimal conditions for manifestation thereof, decreases in the following order: E. coli WP2 (the wild type) → E. coli WP2 exr - and E. coli B → E. coli WP2 uvr A6 → E. coli WP2 rec Al and E. coli WP2 hcr - exr - . It was detected that 0.14 M NaCl solution sensitizes the anoxic cells of some E. coli strains to the effect of γ-radiation. It was established that mutation of the uvr A-gene increases sharply the sensitivity of cells to iradiation under the anoxic conditions in the presence of NaCl, the reverse'' oxygen effect being observed

Metabolic Prosthesis for Oxygenation of Ischemic Tissue

Energy Technology Data Exchange (ETDEWEB)

Greenbaum, Elias [ORNL

2009-01-01

This communication discloses new ideas and preliminary results on the development of a "metabolic prosthesis" for local oxygenation of ischemic tissue under physiological neutral conditions. We report for the first time the selective electrolysis of physiological saline by repetitively pulsed charge-limited electrolysis for the production of oxygen and suppression of free chlorine. For example, using 800 A amplitude current pulses and <200 sec pulse durations, we demonstrated prompt oxygen production and delayed chlorine production at the surface of a shiny 0.85 mm diameter spherical platinum electrode. The data, interpreted in terms of the ionic structure of the electric double layer, suggest a strategy for in situ production of metabolic oxygen via a new class of "smart" prosthetic implants for dealing with ischemic disease such as diabetic retinopathy. We also present data indicating that drift of the local pH of the oxygenated environment can be held constant using a feedback-controlled three electrode electrolysis system that chooses anode and cathode pair based on pH data provided by local microsensors. The work is discussed in the context of diabetic retinopathy since surgical techniques for multielectrode prosthetic implants aimed at retinal degenerative diseases have been developed.

Iron-responsive olfactory uptake of manganese improves motor function deficits associated with iron deficiency.

Directory of Open Access Journals (Sweden)

Jonghan Kim

Full Text Available Iron-responsive manganese uptake is increased in iron-deficient rats, suggesting that toxicity related to manganese exposure could be modified by iron status. To explore possible interactions, the distribution of intranasally-instilled manganese in control and iron-deficient rat brain was characterized by quantitative image analysis using T1-weighted magnetic resonance imaging (MRI. Manganese accumulation in the brain of iron-deficient rats was doubled after intranasal administration of MnCl(2 for 1- or 3-week. Enhanced manganese level was observed in specific brain regions of iron-deficient rats, including the striatum, hippocampus, and prefrontal cortex. Iron-deficient rats spent reduced time on a standard accelerating rotarod bar before falling and with lower peak speed compared to controls; unexpectedly, these measures of motor function significantly improved in iron-deficient rats intranasally-instilled with MnCl(2. Although tissue dopamine concentrations were similar in the striatum, dopamine transporter (DAT and dopamine receptor D(1 (D1R levels were reduced and dopamine receptor D(2 (D2R levels were increased in manganese-instilled rats, suggesting that manganese-induced changes in post-synaptic dopaminergic signaling contribute to the compensatory effect. Enhanced olfactory manganese uptake during iron deficiency appears to be a programmed "rescue response" with beneficial influence on motor impairment due to low iron status.

Low parathyroid hormone levels in bedridden geriatric patients with vitamin D deficiency.

Science.gov (United States)

Björkman, Mikko P; Sorva, Antti J; Risteli, Juha; Tilvis, Reijo S

2009-06-01

To identify the clinical conditions associated with low parathyroid hormone (PTH) in patients with vitamin D deficiency and to evaluate the stability of the blunted PTH response to vitamin D deficiency over 6 months. Secondary analysis of a randomized double-blind controlled vitamin D supplementation trial. Four long-term care hospitals in Helsinki, Finland. Two hundred eighteen chronically bedridden patients. Plasma 25-hydroxyvitamin D (25-OHD), intact PTH, amino-terminal propeptide of type I procollagen (PINP), carboxy-terminal telopeptide of type I collagen (ICTP), activities of daily living (ADLs), and body mass index (BMI) were measured at baseline and at 6 months. Patient records were reviewed for demographic data. PTH was within reference values (8-73 ng/L) despite low 25-OHD level (bedridden patients with vitamin D deficiency. Attenuated parathyroid function appears to be associated with immobilization that causes accelerated bone resorption. Further studies addressing the possible adverse effects of low PTH are warranted.

Density functional study the interaction of oxygen molecule with defect sites of graphene

Energy Technology Data Exchange (ETDEWEB)

Qi Xuejun [State Key Laboratory of Coal Combustion, Wuhan 430074 (China); Guo Xin, E-mail: guoxin@mail.hust.edu.cn [State Key Laboratory of Coal Combustion, Wuhan 430074 (China); Zheng Chuguang [State Key Laboratory of Coal Combustion, Wuhan 430074 (China)

2012-10-15

Highlights: Black-Right-Pointing-Pointer The defect sites existed on the graphite surface create active sites and enhance the reactivity of carbonaceous material. Black-Right-Pointing-Pointer Oxygen molecule more favor chemisorbed on the graphene surface contains defect sites than the perfect surface. Black-Right-Pointing-Pointer The single active oxygen atom adsorbed on the defect surfaces, it completely insert into the surface. - Abstract: The present article reports a theoretical study of oxygen interacted with graphene surface containing defect sites on the atomic level by employing the density functional theory combined with the graphene cluster model. It was founded that oxygen molecule prefers to be chemisorbed on the graphene surface containing defect sites compared to the perfect surface. The adsorption energy of O{sub 2} on the double defect site is about 2.5 times as large as that on the perfect graphene surface. Moreover, the oxygen molecule interacts with S-W defect site gives rise to stable epoxy structure, which pulling the carbon atom outward from the original site in the direction perpendicular to the surface. If the oxygen molecule is adsorbed on the single vacancy site, two C-O bonds are formed on the graphene surface. However, when the oxygen molecule is chemisorbed on the double vacancy site, the oxygen atoms substitute the missing carbon atom's position in the carbon plane and form a hexagonal structure on the graphene network. The results indicate that single active oxygen atom approaches the defect site, it's completely adsorbed in the plane and high energy is released. In all cases, the interaction of an oxygen atom with defect surface involves an exothermic process. The defect site creates active sites on the surface of graphene and produces catalytic effects during the process of oxidation of carbonaceous materials.

Niacin deficiency delays DNA excision repair and increases spontaneous and nitrosourea-induced chromosomal instability in rat bone marrow.

Science.gov (United States)

Kostecki, Lisa M; Thomas, Megan; Linford, Geordie; Lizotte, Matthew; Toxopeus, Lori; Bartleman, Anne-Pascale; Kirkland, James B

2007-12-01

We have shown that niacin deficiency impairs poly(ADP-ribose) formation and enhances sister chromatid exchanges and micronuclei formation in rat bone marrow. We designed the current study to investigate the effects of niacin deficiency on the kinetics of DNA repair following ethylation, and the accumulation of double strand breaks, micronuclei (MN) and chromosomal aberrations (CA). Weanling male Long-Evans rats were fed niacin deficient (ND), or pair fed (PF) control diets for 3 weeks. We examined repair kinetics by comet assay in the 36h following a single dose of ethylnitrosourea (ENU) (30mg/kg bw). There was no effect of ND on mean tail moment (MTM) before ENU treatment, or on the development of strand breaks between 0 and 8h after ENU. Repair kinetics between 12 and 30h were significantly delayed by ND, with a doubling of area under the MTM curve during this period. O(6)-ethylation of guanine peaked by 1.5h, was largely repaired by 15h, and was also delayed in bone marrow cells from ND rats. ND significantly enhanced double strand break accumulation at 24h after ENU. ND alone increased chromosome and chromatid breaks (four- and two-fold). ND alone caused a large increase in MN, and this was amplified by ENU treatment. While repair kinetics suggest that ND may be acting by creating catalytically inactive PARP molecules with a dominant-negative effect on repair processes, the effect of ND alone on O(6)-ethylation, MN and CA, in the absence of altered comet results, suggests additional mechanisms are also leading to chromosomal instability. These data support the idea that the bone marrow cells of niacin deficient cancer patients may be more sensitive to the side effects of genotoxic chemotherapy, resulting in acute bone marrow suppression and chronic development of secondary leukemias.

Iron-Deficiency Anemia

Medline Plus

Full Text Available ... Research Home / < Back To Health Topics / Iron-Deficiency Anemia Iron-Deficiency Anemia Also known as Leer en español Iron-deficiency ... iron-deficiency anemia. Blood tests to screen for iron-deficiency anemia To screen for iron-deficiency anemia, your doctor ...

Some aspects of the oxygen-deficient conditions and denitrification in the Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

Naqvi, S.W.A.

Utilizing a fairly large amount of recently collected data, some outstanding questions concerning the Arabian Sea denitrification problem are addressed. The true level of dissolved oxygen, determined colorimetrically, are about an order of magnitude...

Effect of 2,3-diphosphoglycerate on oxygen affinity of blood in sickle cell anemia

Science.gov (United States)

Charache, Samuel; Grisolia, Santiago; Fiedler, Adam J.; Hellegers, Andre E.

1970-01-01

Blood of patients with sickle cell anemia (SS) exhibits decreased affinity for oxygen, although the oxygen affinity of hemoglobin S is the same as that of hemoglobin A. SS red cells contain more 2,3-diphosphoglycerate (DPG) than normal erythrocytes. The oxygen affinity of hemolyzed red cells is decreased by added DPG, and hemolysates prepared from SS red cells do not differ from normal hemolysates in this regard. Reduction of oxygen affinity to the levels found in intact SS red cells required DPG concentrations in excess of those found in most SS patients. The same was true of oxygen affinity of patients with pyruvate kinase deficiency. Other organic phosphates, as well as inorganic ions, are known to alter the oxygen affinity of dilute solutions of hemoglobin. These substances, the state of aggregation of hemoglobin molecules, and cytoarchitectural factors probably play roles in determining oxygen affinity of both normal and SS red cells. PMID:5443181

Double trisomy (48,XXX,+18) with features of Roberts syndrome

Energy Technology Data Exchange (ETDEWEB)

Descartes, M.; Longshore, J.W.; Crawford, E. [Univ. of Alabama, Birmingham, AL (United States)] [and others

1994-09-01

We report an infant with double trisomy 48,XXX,+18, who also displayed features of Roberts syndrome. All previously published cases with similar double trisomy have presented with features of trisomy 18 syndrome. The chromosome analysis done at birth revealed the double trisomy; parental chromosomes were normal. The proband presented with microbrachycephaly, unilateral cleft lip and palate, choanal atresia, midfacial capillary hemanioma, thin nares, shallow orbits, malformed ears, sparse hair, hypomelia of the upper limbs, rocker-bottom feet, auricular septal defect and agenesis of the corpus callosum. Characteristic features of Roberts syndrome included hypomelia, midfacial defects, and severe growth deficiency. Among the many different features reported in the literature for patients with trisomy 18 syndrome, the most consistent were growth deficiency, clenched fingers and congenital heart defects (e.g. VSD, ASD, PDA). Although some of our patient`s features such as cleft lip and cleft palate, low-set malformed ears, ASD, defects of the corpus callosum, choanal atresia, radial aplasia could also be seen in trisomy 18 syndrome (in 10-50% of the cases), her phenotype was more typical of Roberts syndrome because of symmetrical hypomelia and midfacial defects. Our patient`s chromosomes did not show premature separation of centromeric heterochromatin, a feature reported to occur in approximately one-half of individuals with Roberts syndrome. Sporadic aneuploidy involving different chromosomes has been found in lymphocyte cultures from some Roberts syndrome patients and is considered by some authors as a mitotic mutant. This aneuploidy is most likely to be chromosome gain. The simultaneous occurrence of trisomy X and 18 is extremely rare with only 11 cases having been reported in the literature. Our patient is unique since she has the double trisomy in addition to the characteristic features of Roberts syndrome.

Iron-Deficiency Anemia

Science.gov (United States)

... To Health Topics / Iron-Deficiency Anemia Iron-Deficiency Anemia Also known as Leer en español Iron-deficiency ... anemia. Blood tests to screen for iron-deficiency anemia To screen for iron-deficiency anemia, your doctor ...

Oxidative Stress in Cardiac Mitochondria Caused by Copper Deficiency May Be Insufficient to Damage Mitochondrial Proteins

Science.gov (United States)

Copper (Cu) deficiency may promote the generation of reactive oxygen species (ROS) by the mitochondrial electron transport chain through inhibition of cytochrome c oxidase (CCO) and increased reduction of respiratory complexes upstream from CCO. In the present study, respiration, H2O2 production and...

Ferrous bisglycinate 25 mg iron is as effective as ferrous sulfate 50 mg iron in the prophylaxis of iron deficiency and anemia during pregnancy in a randomized trial

DEFF Research Database (Denmark)

Milman, Nils; Jønsson, Lisbeth; Dyre, Pernille

2014-01-01

OBJECTIVE: To compare the effects of oral ferrous bisglycinate 25 mg iron/day vs. ferrous sulfate 50 mg iron/day in the prevention of iron deficiency (ID) and iron deficiency anemia (IDA) in pregnant women. Design: Randomized, double-blind, intention-to-treat study. Setting: Antenatal care clinic...

Plasminogen activation independent of uPA and tPA maintains wound healing in gene-deficient mice

DEFF Research Database (Denmark)

Lund, Leif R; Green, Kirsty A; Stoop, Allart A

2006-01-01

Simultaneous ablation of the two known activators of plasminogen (Plg), urokinase-type (uPA) and the tissue-type (tPA), results in a substantial delay in skin wound healing. However, wound closure and epidermal re-epithelialization are significantly less impaired in uPA;tPA double-deficient mice ...

Iron-Deficiency Anemia

Medline Plus

Full Text Available ... To Health Topics / Iron-Deficiency Anemia Iron-Deficiency Anemia Also known as Leer en español Iron-deficiency ... anemia. Blood tests to screen for iron-deficiency anemia To screen for iron-deficiency anemia, your doctor ...

Hydroponics on a chip: analysis of the Fe deficient Arabidopsis thylakoid membrane proteome.

Science.gov (United States)

Laganowsky, Arthur; Gómez, Stephen M; Whitelegge, Julian P; Nishio, John N

2009-04-13

The model plant Arabidopsis thaliana was used to evaluate the thylakoid membrane proteome under Fe-deficient conditions. Plants were cultivated using a novel hydroponic system, called "hydroponics on a chip", which yields highly reproducible plant tissue samples for physiological analyses, and can be easily used for in vivo stable isotope labeling. The thylakoid membrane proteome, from intact chloroplasts isolated from Fe-sufficient and Fe-deficient plants grown with hydroponics on a chip, was analyzed using liquid chromatography coupled to mass spectrometry. Intact masses of thylakoid membrane proteins were measured, many for the first time, and several proteins were identified with post-translational modifications that were altered by Fe deficiency; for example, the doubly phosphorylated form of the photosystem II oxygen evolving complex, PSBH, increased under Fe-deficiency. Increased levels of photosystem II protein subunit PSBS were detected in the Fe-deficient samples. Antioxidant enzymes, including ascorbate peroxidase and peroxiredoxin Q, were only detected in the Fe-deficient samples. We present the first biochemical evidence that the two major LHC IIb proteins (LHCB1 and LHCB2) may have significantly different functions in the thylakoid membrane. The study illustrates the utility of intact mass proteomics as an indispensable tool for functional genomics. "Hydroponics on a chip" provides the ability to grow A. thaliana under defined conditions that will be useful for systems biology.

Effects of oxygen during γ-irradiation of Micrococcus radiodurans

International Nuclear Information System (INIS)

Myers, D.K.; Johnson, L.D.

1977-01-01

A study has been made of the effects of oxygen on the yield of double strand breaks in the DNA of Micrococcus radiodurans, and of the relation of these effects to cell death. The o.e.r. values for cell survival were considerably smaller than those for the yield of double strand breaks, although they showed similar trends after irradiation in different media. The o.e.r. values for the inhibition of post-irradiation enzymatic repair were similar to those for cell survival. The o.e.r. for radiation-induced breaks in DNA therefore seems to depend on radiochemical reactions that are occurring during irradiation rather than on a preferential enzymatic repair of those strand breaks that are produced by anoxic irradiation. Cell survival depends less on the number of double strand breaks produced than on the ability of the cell to repair the double strand breaks. The maximum yield of double strand breaks after oxic γ-irradiation was approximately 1.7 breaks/krad/10 10 Daltons, corresponding to 1 break per 610 eV. (U.K.)

Effects of oxygen during. gamma. irradiation of Micrococcus radiodurans

Energy Technology Data Exchange (ETDEWEB)

Myers, D K; Johnson, L D [Atomic Energy of Canada Ltd., Chalk River, Ontario. Chalk River Nuclear Labs.

1977-09-01

A study has been made of the effects of oxygen on the yield of double strand breaks in the DNA of Micrococcus radiodurans, and of the relation of these effects to cell death. The OER values for cell survival were considerably smaller than those for the yield of double strand breaks, although they showed similar trends after irradiation in different media. The OER values for the inhibition of post-irradiation enzymatic repair were similar to those for cell survival. The OER for radiation-induced breaks in DNA therefore seems to depend on radiochemical reactions that are occurring during irradiation rather than on a preferential enzymatic repair of those strand breaks that are produced by anoxic irradiation. Cell survival depends less on the number of double strand breaks produced than on the ability of the cell to repair the double strand breaks. The maximum yield of double strand breaks after oxic ..gamma.. irradiation was approximately 1.7 breaks/krad/10/sup 10/Daltons, corresponding to 1 break per 610 eV.

Deficiência de ferro nas afecções gastrointestinais do adulto Iron deficiency related to gastrointestinal diseases in adults

Directory of Open Access Journals (Sweden)

Cyrla Zaltman

2010-06-01

Full Text Available A anemia por deficiência de ferro (ADF ou a deficiência de ferro (DF isolada são comuns em crianças e mulheres pré-menopausa. Entretanto, em adultos do sexo masculino e mulheres pós-menopausa, essa condição se associa frequentemente a perdas sanguíneas gastrointestinais ou mal absorção. A prevalência das lesões gastrointestinais torna essencial o exame do aparelho digestório superior e inferior através da endoscopia. Investigações complementares devem ser realizadas se os procedimentos endoscópicos não evidenciarem sangramento em situações clínicas, tais como a necessidade de múltiplas hemotransfusões, a ausência de sangramento visível à endoscopia digestiva alta e colonoscopia e a falta de resposta à reposição de ferro.Esses casos devem ser direcionados para investigação do intestino delgado com métodos radiológicos ou, mais recentemente, com a cápsula endoscópica e da enteroscopia com duplo balão. A cintigrafia com hemácias marcadas e a angiografia têm papel restrito, sendo utilizadas apenas no sangramento aberto. O tratamento varia de acordo com a etiologia, a intensidade da perda sanguínea e da deficiência de ferro.Iron deficiency anaemia and isolated iron deficiency are common in children and pre-menopausal women. However, in male adults and post-menopausal women this condition is most frequently caused by gastrointestinal blood loss or malabsorption. The prevalence of gastrointestinal lesions makes the examination by endoscopy of both upper and lower gastrointestinal tracts essential. Further investigations, when the initial exams are negative, are only warranted in cases of multiple transfusions, visible blood loss or lack of response to oral iron supplementation. In these cases examinations should be focused on the small bowel by radiological methods or more recently using capsule endoscopy and double balloon enteroscopy. Nuclear medicine and angiography have a limited role to play in this

Oxygen requirements for formation and activity of the squalene expoxidase in Saccharomyces cerevisiae

Science.gov (United States)

Jahnke, L.; Klein, H. P.

1983-01-01

The effect of oxygen on squalene epoxidase activity in Saccharomyces cerevisiae was investigated. In cells grown in standing cultures, the epoxidase was localized mainly in the 'mitochondrial' fraction. Upon aeration, enzyme activity increased and the newly formed enzyme was associated with the 'microsomal' fraction. At 0.03 percent (vol/vol) oxygen, epoxidase levels doubled, whereas the ergosterol level was only slightly increased. Cycloheximide inhibited the increase in epoxidase under these conditions. An apparent K sub m for oxygen of 0.38 percent (vol/vol) was determined from a crude particulate preparation for the epoxidase.

Hematopoietic Stem Cells from Ts65Dn Mice Are Deficient in the Repair of DNA Double-Strand Breaks.

Science.gov (United States)

Wang, Yingying; Chang, Jianhui; Shao, Lijian; Feng, Wei; Luo, Yi; Chow, Marie; Du, Wei; Meng, Aimin; Zhou, Daohong

2016-06-01

Down syndrome (DS) is a genetic disorder caused by the presence of an extra partial or whole copy of chromosome 21. In addition to musculoskeletal and neurodevelopmental abnormalities, children with DS exhibit various hematologic disorders and have an increased risk of developing acute lymphoblastic leukemia and acute megakaryocytic leukemia. Using the Ts65Dn mouse model, we investigated bone marrow defects caused by trisomy for 132 orthologs of the genes on human chromosome 21. The results showed that, although the total bone marrow cellularity as well as the frequency of hematopoietic progenitor cells (HPCs) was comparable between Ts65Dn mice and their age-matched euploid wild-type (WT) control littermates, human chromosome 21 trisomy led to a significant reduction in hematopoietic stem cell (HSC) numbers and clonogenic function in Ts65Dn mice. We also found that spontaneous DNA double-strand breaks (DSBs) were significantly increased in HSCs from the Ts65Dn mice, which was correlated with the significant reduction in HSC clonogenic activity compared to those from WT controls. Moreover, analysis of the repair kinetics of radiation-induced DSBs revealed that HSCs from Ts65Dn mice were less proficient in DSB repair than the cells from WT controls. This deficiency was associated with a higher sensitivity of Ts65Dn HSCs to radiation-induced suppression of HSC clonogenic activity than that of euploid HSCs. These findings suggest that an additional copy of genes on human chromosome 21 may selectively impair the ability of HSCs to repair DSBs, which may contribute to DS-associated hematological abnormalities and malignancies.

Absence-like and tonic seizures in aspartoacylase/attractin double-mutant mice.

Science.gov (United States)

Gohma, Hiroshi; Kuramoto, Takashi; Matalon, Reuben; Surendran, Sankar; Tyring, Stephen; Kitada, Kazuhiro; Sasa, Masashi; Serikawa, Tadao

2007-04-01

The Spontaneously Epileptic Rat (SER), a double-mutant for tremor and zitter mutations, shows spontaneous occurrences of absence-like and tonic seizures. Several lines of evidence suggest that the combined effect of Aspa and Atrn mutations is the most likely cause of the epileptic phenotype of the SER. To address this issue, we produced a new double-mutant mouse line carrying both homozygous Aspa-knockout and Atrn(mg-3J) mutant alleles. The Aspa/Atrn double-mutant mice exhibited absence-like and tonic seizures that were characterized by the appearance of 5-7 Hz spike-wave-like complexes and low voltage fast waves on EEGs. These results demonstrate directly that the simultaneous loss of the Aspa and Atrn gene functions causes epileptic seizures in the mouse and suggest that both Aspa and Atrn deficiencies might be responsible for epileptic seizures in the SER.

Enhancing photocatalytic CO{sub 2} reduction by coating an ultrathin Al{sub 2}O{sub 3} layer on oxygen deficient TiO{sub 2} nanorods through atomic layer deposition

Energy Technology Data Exchange (ETDEWEB)

Zhao, Huilei; Chen, Jiatang; Rao, Guiying; Deng, Wei; Li, Ying, E-mail: yingli@tamu.edu

2017-05-15

Highlights: • Oxygen deficient TiO{sub 2} anatase nanorods are coated with an ultrathin Al{sub 2}O{sub 3} layer by ALD. • Exposed {100} facets and oxygen vacancies promote CO{sub 2} photoreduction to CO and CH{sub 4}. • Al{sub 2}O{sub 3} overlayer passivates surface states and mitigates surface charge recombination. • Two cycles of ALD coating lead to maximum photocatalytic CO{sub 2} reduction. • More than five cycles of ALD coating prohibits electron transfer to the surface. - Abstract: In this work, anatase nanorods (ANR) of TiO{sub 2} with active facet {100} as the major facet were successfully synthesized, and reducing the ANR by NaBH{sub 4} led to the formation of gray colored oxygen deficient TiO{sub 2-x} (ReANR). On the surface of ReANR, a thin layer of Al{sub 2}O{sub 3} was deposited using atomic layer deposition (ALD), and the thickness of Al{sub 2}O{sub 3} varied by the number of ALD cycles (1, 2, 5, 10, 50, 100, or 200). The growth rate of Al{sub 2}O{sub 3} was determined to be 0.25 Å per cycle based on high-resolution TEM analysis, and the XRD result showed the amorphous structure of Al{sub 2}O{sub 3}. All the synthesized photocatalysts (ANR, ReANR, and Al{sub 2}O{sub 3} coated ReANR) were tested for CO{sub 2} photocatalytic reduction in the presence of water vapor, with CO detected as the major reduction product and CH{sub 4} as the minor product. Compared with ANR, ReANR had more than 50% higher CO production and more than ten times higher CH{sub 4} production due to the oxygen vacancies that possibly enhanced CO{sub 2} adsorption and activation. By applying less than 5 cycles of ALD, the Al{sub 2}O{sub 3} coated ReANR had enhanced overall production of CO and CH{sub 4} than uncoated ReANR, with 2 cycles being the optimum, about 40% higher overall production than ReANR. Whereas, both CO and CH{sub 4} production decreased with increasing number of ALD cycles when more than 5 cycles were applied. Photoluminescence (PL) analysis showed an

Scintigraphic assessment of double-chambered right ventricle

International Nuclear Information System (INIS)

Nishimura, Tsunehiko; Uehara, Toshiisa; Hayashida, Kohei

1987-01-01

A double-chambered right ventricle is often clinically misdiagnosed and may be missed even during cardiac catheterization. We encountered a 56-year-old male who had abnormal right ventricular thallium-201 uptake and a photon deficient area in the right ventricle by radionuclide cardioangiography. These findings strongly suggested the existence of anomalous muscle band in the right ventricle. It was demonstrated by contrast angiography that the right ventricle was divided into two chambers by a hypertrophic muscular band; the pressure gradient in the right ventricle was 98 mmHg. (author)

Marine species in ambient low-oxygen regions subject to double jeopardy impacts of climate change.

Science.gov (United States)

Stortini, Christine H; Chabot, Denis; Shackell, Nancy L

2017-06-01

We have learned much about the impacts of warming on the productivity and distribution of marine organisms, but less about the impact of warming combined with other environmental stressors, including oxygen depletion. Also, the combined impact of multiple environmental stressors requires evaluation at the scales most relevant to resource managers. We use the Gulf of St. Lawrence, Canada, characterized by a large permanently hypoxic zone, as a case study. Species distribution models were used to predict the impact of multiple scenarios of warming and oxygen depletion on the local density of three commercially and ecologically important species. Substantial changes are projected within 20-40 years. A eurythermal depleted species already limited to shallow, oxygen-rich refuge habitat (Atlantic cod) may be relatively uninfluenced by oxygen depletion but increase in density within refuge areas with warming. A more stenothermal, deep-dwelling species (Greenland halibut) is projected to lose ~55% of its high-density areas under the combined impacts of warming and oxygen depletion. Another deep-dwelling, more eurythermal species (Northern shrimp) would lose ~4% of its high-density areas due to oxygen depletion alone, but these impacts may be buffered by warming, which may increase density by 8% in less hypoxic areas, but decrease density by ~20% in the warmest parts of the region. Due to local climate variability and extreme events, and that our models cannot project changes in species sensitivity to hypoxia with warming, our results should be considered conservative. We present an approach to effectively evaluate the individual and cumulative impacts of multiple environmental stressors on a species-by-species basis at the scales most relevant to managers. Our study may provide a basis for work in other low-oxygen regions and should contribute to a growing literature base in climate science, which will continue to be of support for resource managers as climate change

Postreplicational formation and repair of DNA double-strand breaks in UV-irradiated Escherichia coli uvrB cells

International Nuclear Information System (INIS)

Wang, Tzuchien V.; Smith, K.C.

1986-01-01

The number of DNA double-strand breaks formed in UV-irradiated uvrB recF recB cells correlates with the number of unrepaired DNA daughter-strand gaps, and is dependent on DNA synthesis after UV-irradiation. These results are consistent with the model that the DNA double-strand breaks that are produced in UV-irradiated excision-deficient cells occur as the result of breaks in the parental DNA opposite unrepaired DNA daughter-strand gaps. By employing a temperature-sensitive recA200 mutation, we have devised an improved assay for studying the formation and repair of these DNA double-strand breaks. Possible mechanisms for the postreplication repair of DNA double-strand breaks are discussed. (Auth.)

Application of international double taxation conventions in Romania

Directory of Open Access Journals (Sweden)

Florin Dumiter

2016-12-01

Full Text Available In this article we sought to address the international double taxation phenomenon from two different standpoints. To begin with, in the first part we analysed the framework of international double taxation, and how this topic was tackled in both Romanian and international literature.International double taxation has been analyzed, mutatis mutandis, from an economic perspective, more precisely in terms of the implications that it generates on economies, on added value, on capital flows, on the internationalisation of business. Second, I believed it was important to analyse international double taxation from a legal perspective, through the jurisdictional effects of obtaining income or holding property at the European or international level. Romania's case is carefully approached in this paper, aiming to highlight the issues Romania is facing concerning cooperation in tax matters with authorities from other countries, how the more than 80 double taxation conventions are applied and interpreted, but also other aspects that should be considered by the Romanian tax authorities, based on the provisions of the Fiscal Code and the Fiscal Procedure Code. The article ends by presenting, commenting on and analysing two test cases in international double taxation, of remarkable importance and actuality for Romanian jurisprudence to observe how complex double taxation mechanisms operate in practice. The conclusion of this article emphasises the importance ofsignificant “steps” achieved by Romania on the path to creating a true “fiscal area” in the European Union, as well as the “corridors” that should be inserted to correct economi c – legal and economic deficiencies and gaps, in order to strengthen the fiscal area.

The Use of OXYGEN-18 in the Development of Methods for Controlled Sputter Deposition of High Critical Transition Temperature Material Thin Films of Predicted Composition and Good Uniformity

Science.gov (United States)

Tidrow, Steven Clay

Two primary concerns, in the sputter deposition of high T_{c} material films, are the prevention of oxygen deficiency in the films and the elimination of the negative ion effect. "Oxygen deficiency" occurs when the amount of oxygen incorporated into the film is less than the amount of oxygen required to form the superconducting material lattice. Oxygen deficiency is due to the volatile nature of oxygen. The negative ion effect occurs when an atom or molecule (typically oxygen) gains an extra electron, is accelerated away from the target and impinges upon a film being grown directly in front of the sputtering target. The impinging particle has enough energy to cause resputtering of the deposited film. The presence of Sr and to a greater extent Ba, may enhance the negative ion effect in these materials. However, it is oxygen which readily forms negative ions that is primarily responsible for the negative ion effect. Thus, oxygen must be given special attention in the sputter deposition of high T_{c} material films. A specially designed sputtering system is used to demonstrate that the negative ion effect can be reduced such that large uniform high T_{c} material films possessing predicted and repeated composition can be grown in an on-axis arrangement. Utilizing this same sputtering system and the volatile nature of oxygen, it is demonstrated that oxygen processes occurring in the chamber during growth of high T_ {c} material films can be investigated using the tracer ^{18}O. In particular, it is shown that ^{18}O can be utilized as a tool for (1) investigating the negative ion effect, (2) investigating oxygen incorporation into high T_{c} material films, (3) investigating oxygen incorporation into the target, (4) tailoring films for oxygen migration and interface investigations and (5) tailoring films for the other specific oxygen investigations. Such sputtering systems that utilize the tracer ^{18}O are necessary for systematic growth of high T_ {c} material films

PHYTOALEXIN DEFICIENT 4 affects reactive oxygen species metabolism, cell wall and wood properties in hybrid aspen (Populus tremula L. × tremuloides).

Science.gov (United States)

Ślesak, Ireneusz; Szechyńska-Hebda, Magdalena; Fedak, Halina; Sidoruk, Natalia; Dąbrowska-Bronk, Joanna; Witoń, Damian; Rusaczonek, Anna; Antczak, Andrzej; Drożdżek, Michał; Karpińska, Barbara; Karpiński, Stanisław

2015-07-01

The phytoalexin deficient 4 (PAD4) gene in Arabidopsis thaliana (AtPAD4) is involved in the regulation of plant--pathogen interactions. The role of PAD4 in woody plants is not known; therefore, we characterized its function in hybrid aspen and its role in reactive oxygen species (ROS)-dependent signalling and wood development. Three independent transgenic lines with different suppression levels of poplar PAD expression were generated. All these lines displayed deregulated ROS metabolism, which was manifested by an increased H2O2 level in the leaves and shoots, and higher activities of manganese superoxide dismutase (MnSOD) and catalase (CAT) in the leaves in comparison to the wild-type plants. However, no changes in non-photochemical quenching (NPQ) between the transgenic lines and wild type were observed in the leaves. Moreover, changes in the ROS metabolism in the pad4 transgenic lines positively correlated with wood formation. A higher rate of cell division, decreased tracheid average size and numbers, and increased cell wall thickness were observed. The results presented here suggest that the Populus tremula × tremuloides PAD gene might be involved in the regulation of cellular ROS homeostasis and in the cell division--cell death balance that is associated with wood development. © 2014 John Wiley & Sons Ltd.

Zooplankton Responses to Low-Oxygen Condition upon a Shallow Oxygen Minimum Zone in the Upwelling Region off Chile

Science.gov (United States)

Hidalgo, P.; Escribano, R.

2015-12-01

A shallow oxygen minimum zone (OMZ) is a critical component in the coastal upwelling ecosystem off Chile. This OMZ causes oxygen-deficient water entering the photic layer and affecting plankton communities having low tolerance to hypoxia. Variable, and usually species-dependent, responses of zooplankton to hypoxia condition can be found. Most dominant species avoid hypoxia by restricting their vertical distribution, while others can temporarily enter and even spent part of their life cycle within the OMZ. Whatever the case, low-oxygen conditions appear to affect virtually all vital rates of zooplankton, such as mortality, fecundity, development and growth and metabolism, and early developmental stages seem more sensitive, with significant consequences for population and community dynamics. For most study cases, these effects are negative at individual and population levels. Observations and predictions upon increasing upwelling intensity over the last 20-30 years indicate a gradual shoaling of the OMZ, and so that an expected enhancement of these negative effects of hypoxia on the zooplankton community. Unknown processes of adaptation and community-structure adjustments are expected to take place with uncertain consequences for the food web of this highly productive eastern boundary current ecosystem.

Oxygen Consumption Constrains Food Intake in Fish Fed Diets Varying in Essential Amino Acid Composition

NARCIS (Netherlands)

Subramanian, S.; Geurden, I.; Figueiredo-Silva, A.C.; Nusantoro, S.; Kaushik, S.J.; Verreth, J.A.J.; Schrama, J.W.

2013-01-01

Compromisation of food intake when confronted with diets deficient in essential amino acids is a common response of fish and other animals, but the underlying physiological factors are poorly understood. We hypothesize that oxygen consumption of fish is a possible physiological factor constraining

Oxygen abundances in unevolved metal-poor stars - Interpretation and consequences

International Nuclear Information System (INIS)

Abia, C.; Rebolo, R.

1989-01-01

The oxygen abundance has been determined by analysis of the O I infrared triplet in 30 unevolved field stars of metallicities in the range Fe/H abundance ratio between -0.2 and -3.5. The data show that the O/Fe abundance ratio increases monotonically as metallicity decreases from solar, reaching values in the range 1.0-1.2 at an Fe/H abundance ratio of about -2. The results, when compared with those already published for metal-deficient red giants, suggest that oxygen could have been depleted in the latter. A discussion of the O/Fe abundance ratios in connection with the chemical evolution of the Galaxy is also presented. 83 refs

Modelling Ecosystem Dynamics of the Oxygen Minimum Zones in the Angola Gyre and the Northern Benguela Upwelling System.

Science.gov (United States)

Schmidt, M.; Eggert, A.

2016-02-01

The Angola Gyre and the Northern Benguela Upwelling System are two major oxygen minimum zones (OMZ) of different kind connected by the system of African Eastern Boundary Currents. We discuss results from a 3-dimensional coupled biogeochemical model covering both oxygen-deficient systems. The biogeochemical model component comprises trophic levels up to zooplankton. Physiological properties of organisms are parameterized from field data gained mainly in the course of the project "Geochemistry and Ecology of the Namibian Upwelling System" (GENUS). The challenge of the modelling effort is the different nature of both systems. The Angola Gyre, located in a "shadow zone" of the tropical Atlantic, has a low productivity and little ventilation, hence a long residence time of water masses. In the northern Benguela Upwelling System, trade winds drive an intermittent, but permanent nutrient supply into the euphotic zone which fuels a high coastal productivity, large particle export and high oxygen consumption from dissimilatory processes. In addition to the local processes, oxygen-deficient water formed in the Angola Gyre is one of the source water masses of the poleward undercurrent, which feeds oxygen depleted water into the Benguela system. In order to simulate the oxygen distribution in the Benguela system, both physical transport as well as local biological processes need to be carefully adjusted in the model. The focus of the analysis is on the time scale and the relative contribution of the different oxygen related processes to the oxygen budgets in both the oxygen minimum zones. Although these are very different in both the OMZ, the model is found as suitable to produce oxygen minimum zones comparable with observations in the Benguela and the Angola Gyre as well. Variability of the oxygen concentration in the Angola Gyre depends strongly on organismic oxygen consumption, whereas the variability of the oxygen concentration on the Namibian shelf is governed mostly by

Oxygen potential of uranium--plutonium oxide as determined by controlled-atmosphere thermogravimetry

International Nuclear Information System (INIS)

Swanson, G.C.

1975-10-01

The oxygen-to-metal atom ratio, or O/M, of solid solution uranium-plutonium oxide reactor fuel is a measure of the concentration of crystal defects in the oxide which affect many fuel properties, particularly, fuel oxygen potential. Fabrication of a high-temperature oxygen electrode, employing an electro-active tip of oxygen-deficient solid-state electrolyte, intended to confirm gaseous oxygen potentials is described. Uranium oxide and plutonium oxide O/M reference materials were prepared by in situ oxidation of high purity metals in the thermobalance. A solid solution uranium-plutonium oxide O/M reference material was prepared by alloying the uranium and plutonium metals in a yttrium oxide crucible at 1200 0 C and oxidizing with moist He at 250 0 C. The individual and solid solution oxides were isothermally equilibrated with controlled oxygen potentials between 800 and 1300 0 C and the equilibrated O/M ratios calculated with corrections for impurities and buoyancy effects. Use of a reference oxygen potential of -100 kcal/mol to produce an O/M of 2.000 is confirmed by these results. However, because of the lengthy equilibration times required for all oxides, use of the O/M reference materials rather than a reference oxygen potential is recommended for O/M analysis methods calibrations. (auth)

Magnetoresistance Versus Oxygen Deficiency in Epi-stabilized SrRu1 - x Fe x O3 - δ Thin Films

Science.gov (United States)

Dash, Umasankar; Acharya, Susant Kumar; Lee, Bo Wha; Jung, Chang Uk

2017-03-01

Oxygen vacancies have a profound effect on the magnetic, electronic, and transport properties of transition metal oxide materials. Here, we studied the influence of oxygen vacancies on the magnetoresistance (MR) properties of SrRu1 - x Fe x O3 - δ epitaxial thin films ( x = 0.10, 0.20, and 0.30). For this purpose, we synthesized highly strained epitaxial SrRu1 - x Fe x O3 - δ thin films with atomically flat surfaces containing different amounts of oxygen vacancies using pulsed laser deposition. Without an applied magnetic field, the films with x = 0.10 and 0.20 showed a metal-insulator transition, while the x = 0.30 thin film showed insulating behavior over the entire temperature range of 2-300 K. Both Fe doping and the concentration of oxygen vacancies had large effects on the negative MR contributions. For the low Fe doping case of x = 0.10, in which both films exhibited metallic behavior, MR was more prominent in the film with fewer oxygen vacancies or equivalently a more metallic film. For semiconducting films, higher MR was observed for more semiconducting films having more oxygen vacancies. A relatively large negative MR ( 36.4%) was observed for the x = 0.30 thin film with a high concentration of oxygen vacancies ( δ = 0.12). The obtained results were compared with MR studies for a polycrystal of (Sr1 - x La x )(Ru1 - x Fe x )O3. These results highlight the crucial role of oxygen stoichiometry in determining the magneto-transport properties in SrRu1 - x Fe x O3 - δ thin films.

Effect of caffeine on maximal oxygen uptake in wheelchair rugby players: A randomized, placebo-controlled, double-blind study

Directory of Open Access Journals (Sweden)

Iva Klimešová

2017-03-01

Full Text Available Background: The positive effects of caffeine supplementation on strength-power and endurance performance in healthy athletes have been demonstrated in many studies. A possible mechanism for its ergogenic effect relates to its influence on the central nervous system. Post-traumatic complications in cervical spinal cord injury affect almost all body systems including the nervous system. For this reason, we expect that caffeine will have a different effect of performance in the group of athletes with spinal cord injuries. Objective: To examine the effects of caffeine supplementation on maximal aerobic power in elite wheelchair rugby players. Methods: Seven elite male wheelchair rugby players with complete cervical-level SCI (C4-Th1 were recruited (mean age: 28 ± 5.42 years; mean body mass index: 26 ± 2.84 kg/m2. The effect of caffeine was assessed by an incremental arm ergometer test until volitional exhaustion. The maximal oxygen uptake (VO2max/kg, maximum power (W max/kg, peak heart rate (HR peak, and intensity of perceived exertion (RPE were measured. Participants performed the test twice with a two-week washout period. One hour before each exercise test subjects ingested a capsule of placebo or caffeine (3 mg per kg of body weight. The tests were applied in a double-blind, randomized, repeated-measures, and cross-over design. Wheelchair rugby players were chosen because of the expected high homogeneity of participants - in terms of the type and degree of disability, gender, and age of the players. Results: The monitored parameters were not significantly influenced by caffeine intervention as compared to placebo: VO2max/kg (p = .40, W max/kg (p = .34, HR peak (p = .50 and RPE (p = .50. Conclusions: The current findings suggest that a caffeine dose of 3 mg/kg body mass does not improve oxygen uptake and maximal power in elite wheelchair rugby players.

Iron-Deficiency Anemia

Medline Plus

Full Text Available ... Iron-Deficiency Anemia Iron-Deficiency Anemia Also known as Leer en español Iron-deficiency anemia is a ... address the cause of your iron deficiency, such as any underlying bleeding. If undiagnosed or untreated, iron- ...

Determination of oxygen content in high Tc superconductors by deuteron particle activation analysis

International Nuclear Information System (INIS)

Tao Zhenlan; Yao, Y.D.; Kao, Y.H.

1993-01-01

The experimental method for determining the oxygen content in high T c superconductors is described in detail. This method is applied to determination of oxygen content in high T c Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O samples in which the stoichiometry is varied by reducing the copper and bismuth concentrations. The oxygen concentration is found to vary linearly with Cu(x = 0-0.2) and Bi (x = 0-0.4) deficiencies in YBa 2 Cu 3(1-x )O y and Bi 2(1-x) Sr 2 CaCu 2 O y respectively. X-ray powder diffraction measurements show that the compound of YBa 2 Cu 3(1-x) O y is orthorhombic in the variation range of x = 0-0.2

Clinical and Biological Manifestation of RNF168 Deficiency in Two Polish Siblings

Directory of Open Access Journals (Sweden)

Barbara Pietrucha

2017-12-01

Full Text Available Germline mutations in the RING finger protein gene RNF168 have been identified in a combined immunodeficiency disorder called RIDDLE syndrome. Since only two patients have been described with somewhat different phenotypes, there is need to identify further patients. Here, we report on two Polish siblings with RNF168 deficiency due to homozygosity for a novel frameshift mutation, c.295delG, that was identified through exome sequencing. Both patients presented with immunoglobulin deficiency, telangiectasia, cellular radiosensitivity, and increased alpha-fetoprotein (AFP levels. The younger sibling had a more pronounced neurological and morphological phenotype, and she also carried an ATM gene mutation in the heterozygous state. Immunoblot analyses showed absence of RNF168 protein, whereas ATM levels and function were proficient in lymphoblastoid cells from both patients. Consistent with the absence of RNF168 protein, 53BP1 recruitment to DNA double-strand breaks (DSBs after irradiation was undetectable in lymphoblasts or primary fibroblasts from either of the two patients. γH2AX foci accumulated normally but they disappeared with significant delay, indicating a severe defect in DSB repair. A comparison with the two previously identified patients indicates immunoglobulin deficiency, cellular radiosensitivity, and increased AFP levels as hallmarks of RNF168 deficiency. The variability in its clinical expression despite similar cellular phenotypes suggests that some manifestations of RNF168 deficiency may be modified by additional genetic or epidemiological factors.

Dissimilatory nitrate reduction by Aspergillus terreus isolated from the seasonal oxygen minimum zone in the Arabian Sea

OpenAIRE

Stief, Peter; Fuchs-Ocklenburg, Silvia; Kamp, Anja; Manohar, Cathrine-Sumathi; Houbraken, Jos; Boekhout, Teun; de Beer, Dirk; Stoeck, Thorsten

2014-01-01

Background A wealth of microbial eukaryotes is adapted to life in oxygen-deficient marine environments. Evidence is accumulating that some of these eukaryotes survive anoxia by employing dissimilatory nitrate reduction, a strategy that otherwise is widespread in prokaryotes. Here, we report on the anaerobic nitrate metabolism of the fungus Aspergillus terreus (isolate An-4) that was obtained from sediment in the seasonal oxygen minimum zone in the Arabian Sea, a globally important site of oce...

GRAF1 deficiency blunts sarcolemmal injury repair and exacerbates cardiac and skeletal muscle pathology in dystrophin-deficient mice.

Science.gov (United States)

Lenhart, Kaitlin C; O'Neill, Thomas J; Cheng, Zhaokang; Dee, Rachel; Demonbreun, Alexis R; Li, Jianbin; Xiao, Xiao; McNally, Elizabeth M; Mack, Christopher P; Taylor, Joan M

2015-01-01

double deficiency phenocopied the severe muscle pathologies observed in dystrophin/dysferlin-double null mice. Consistent with a model that GRAF1 facilitates dysferlin-dependent membrane patching, we found that GRAF1 associates with and regulates plasma membrane deposition of dysferlin. Overall, our work indicates that GRAF1 facilitates dysferlin-dependent membrane repair following acute muscle injury. These findings indicate that GRAF1 might play a role in the phenotypic variation and pathological progression of cardiac and skeletal muscle degeneration in muscular dystrophy patients.

The oxygen enhancement ratio for single- and double-strand breaks induced by tritium incorporated in DNA of cultured human T1 cells. Impact of the transmutation effect.

Science.gov (United States)

Tisljar-Lentulis, G; Henneberg, P; Feinendegen, L E; Commerford, S L

1983-04-01

The effect of oxygen, expressed as the oxygen enhancement ratio (OER), on the number of single-strand breaks (SSB) and double-strand breaks (DSB) induced in DNA by the radioactive decay of tritium was measured in human T1 cells whose DNA had been labeled with tritium at carbon atom number 6 of thymidine. Decays were accumulated in vivo under aerobic conditions at 0-1 degrees C and at -196 degrees C and in a nitrogen atmosphere at 0-1 degrees C. The number of SSB and DSB produced was analyzed by sucrose gradient centrifugation. For each tritium decay there were 0.25 DSB in cells exposed to air at 0-1 degrees C and 0.07 in cells kept under nitrogen, indicating an OER of 3.6, a value expected for such low-LET radiation. However, for each tritium decay there were 1.25 SSB in cells exposed to air at 0-1 degrees C and 0.76 in cells kept under nitrogen indicating an OER of only 1.7. The corresponding values for 60Co gamma radiation, expressed as SSB per 100 eV absorbed energy, were 4.5 and 1.0, giving an OER of 4.5. The low OER value found for SSB induced by tritium decay can be explained if 31% of the total SSB produced in air result from transmutation by a mechanism which does not produce DSB and is unaffected by oxygen.

Iron deficiency anaemia: with the conclusion of a need for iron reader

Science.gov (United States)

Lim, Wai Feng; Yap, Boon Kar; Lai, Mei I.; Talik, Noorazrina; Nasser, Ammar Ahmed; Al-Haiqi, Ahmed Mubarak Ahmed; Sankar Krishnan, Prajindra

2017-10-01

In our bloodstream, there are plenty of red blood cells (RBC), which function as an important oxygen carrier in our bodies. Each RBC consists of millions of haemoglobin (Hb), which is made up from globin and iron. If any deficiency/malfunction of any globin, it will lead to anaemia as indicated in low Hb level while iron deficiency anaemia (IDA) is anaemic due to the lacking of iron as indicated in low Hb and ferritin levels. IDA affects almost two billion people globally while anaemia without iron deficiency, such as thalassaemia, affects almost 4.5% in Malaysian population. These anaemic conditions have similar clinical symptoms like fatigue, dizziness, in which disturb their cognitive development and productivity in workplace. In areas without proper medical access, many anaemic individuals were misdiagnosed and treated with iron tablets because they were thought to have iron deficiency anaemia due to low Hb content. But, excess iron is toxic to the body. Misdiagnosis can be avoided by iron status assessment. We hereby review the currently available iron status parameters in laboratory and field study with the conclusion of demonstrating the importance of a need for iron reader, in the effort to reduce the prevalence of IDA globally.

High-pressure oxygenation of thin-wall YBCO single-domain samples

International Nuclear Information System (INIS)

Chaud, X; Savchuk, Y; Sergienko, N; Prikhna, T; Diko, P

2008-01-01

The oxygen annealing of ReBCO bulk material, necessary to achieve superconducting properties, usually induces micro- and macro-cracks. This leads to a crack-assisted oxygenation process that allows oxygenating large bulk samples faster than single crystals. But excellent superconducting properties are cancelled by the poor mechanical ones. More progressive oxygenation strategy has been shown to reduce drastically the oxygenation cracks. The problem then arises to keep a reasonable annealing time. The concept of bulk Y123 single-domain samples with thin-wall geometry has been introduced to bypass the inherent limitation due to a slow oxygen diffusion rate. But it is not enough. The use of a high oxygen pressure (16 MPa) enables to speed up further the process. It introduces a displacement in the equilibrium phase diagram towards higher temperatures, i.e., higher diffusion rates, to achieve a given oxygen content in the material. Remarkable results were obtained by applying such a high pressure oxygen annealing process on thin-wall single-domain samples. The trapped field of 16 mm diameter Y123 thin-wall single-domain samples was doubled (0.6T vs 0.3T at 77K) using an annealing time twice shorter (about 3 days). The initial development was made on thin bars. The advantage of thin-wall geometry is that such an annealing can be applied directly to a much larger sample

Multiple pathways of DNA double-strand break processing in a mutant Indian muntjac cell line

International Nuclear Information System (INIS)

Bouffler, S.D.; Jha, B.; Johnson, R.T.

1990-01-01

DNA break processing is compared in the Indian muntjac cell lines, SVM and DM. The initial frequencies and resealing of X-ray generated single- and double-strand breaks are similar in the two cell lines. Inhibiting the repair of UV damage leads to greater double-strand breakage in SVM than in DM, and some of these breaks are not repaired; however, repair-associated single-strand breakage and resealing are normal. Dimethylsulfate also induces excess double-strand breakage in SVM, and these breaks are irreparable. Restricted plasmids are reconstituted correctly in SVM at approximately 30% of the frequency observed in DM. Thus SVM has a reduced capacity to repair certain types of double-strand break. This defect is not due to a DNA ligase deficiency. We conclude that DNA double-strand breaks are repaired by a variety of pathways within mammalian cells and that the structure of the break or its mode of formation determines its subsequent fate

Conditions for oxygen-deficient combustion during accidents with severe core concrete thermal attack

International Nuclear Information System (INIS)

Luangdilok, W.; Elicson, G.T.; Berger, W.E. Jr.

1993-01-01

This paper addresses the interactions between MCCI (molten core-concrete interactions)-induced offgas releases, mostly the combustible gases, natural circulation between the cavity and the lower containment based on recent research developments in the area of mixed convection flow (Epstein, et al., 1989; Epstein, 1988; Epstein, 1992) between compartments, and their effects on combustion in PWR containments during prolonged severe accidents. Specifically, large dry PWR containments undergoing severe core-concrete attack during station blackouts where the containment atmosphere is expected to be inerted are objects of this analysis. The purpose of this paper, given the conditions that oxygen can be brought to the cavity, is to demonstrate that consumption of most oxygen present in the containment can be achieved in a reasonable time scale assuming that combustion is not subject to flammability limits due to the high cavity temperatures. The conditions for cavity combustion depend on several factors including good gas flowpaths between the cavity and other containment regions, and combustion processes within the cavity with the hot debris acting as the ignition source

Selenium deficiency aggravates T-2 toxin-induced injury of primary neonatal rat cardiomyocytes through ER stress.

Science.gov (United States)

Xu, Jing; Pan, Shengchi; Gan, Fang; Hao, Shu; Liu, Dandan; Xu, Haibin; Huang, Kehe

2018-04-01

Keshan disease is a potentially fatal cardiomyopathy in humans. Selenium deficiency, T-2 toxin, and myocarditis virus are thought to be the major factors contributing to Keshan disease. But the relationship among these three factors is poorly described. This study aims to explore whether selenium deficiency aggravates T-2 toxin-induced cardiomyocyte injury and its underlying mechanism. Cardiomyocytes were isolated from neonatal rat and cultured at the physiological (2.0 μM) or lower concentrations of selenium with different concentrations of T-2 toxin. Our results showed that selenium deficiencies aggravated T-2 toxin-induced cardiomyocyte injury in a concentration-dependent manner as demonstrated by MTT bioassay, LDH activity, reactive oxygen species levels and caspase 3 protein expressions. T-2 toxin treatment significantly increased mRNA expressions for stress proteins GRP78 and CHOP in cardiomyocytes compared with the control. Selenium deficiencies further promoted GRP78, CHOP and p-eIF2α expressions. Knockdown of CHOP by the specific small interfering RNA eliminated the effect of selenium deficiencies on T-2 toxin-induced injury. It could be concluded that selenium deficiency aggravates T-2 toxin-induced cardiomyocyte injury through initiating more aggressive endoplasmic reticulum stress. Copyright © 2018 Elsevier B.V. All rights reserved.

Evidence for induction of DNA double strand breaks in the bystander response to targeted soft X-rays in CHO cells

International Nuclear Information System (INIS)

Kashino, Genro; Prise, Kevin M.; Schettino, Giuseppe; Folkard, Melvyn; Vojnovic, Borivoj; Michael, Barry D.; Suzuki, Keiji; Kodama, Seiji; Watanabe, Masami

2004-01-01

This study investigated the role of DNA double strand breaks and DNA base damage in radiation-induced bystander responses in Chinese hamster ovary (CHO) cell lines. Two CHO repair-deficient clones, xrs5 (DNA double strand break repair-deficient) and EM9 (DNA base excision repair-deficient) were used in addition to the wild type (CHO). The Gray Cancer Institute ultrasoft X-ray microprobe is a powerful tool for investigating the bystander response, because it permits the irradiation of only a single nucleus of a cell, as reported previously. In order to investigate the bystander effect in each repair-deficient cell line, we irradiated a single cell within a population and scored the formation of micronuclei. When a single nucleus in the population was targeted with 1 Gy, elevated numbers of micronuclei were induced in the neighbouring unirradiated cells in the EM9 and xrs5 cell lines, whereas induction was not observed in CHO. The induction of micronuclei in xrs5 was significantly higher than that in EM9. Under these conditions, the surviving fraction in the neighbouring cells was significantly lower in xrs5 than in the other cell lines, showing a higher cell killing effect in xrs5. To confirm that bystander factors secreted from irradiated cells caused these effects, we carried out medium transfer experiments using conventional X-irradiation. Medium conditioned for 24 h with irradiated cells was transferred to unirradiated cells and elevated induction of micronuclei was observed in xrs5. These results suggest that DNA double strand breaks rather than base damage are caused by factors secreted in the medium from irradiated cells

NADPH oxidase 1 deficiency alters caveolin phosphorylation and angiotensin II-receptor localization in vascular smooth muscle.

Science.gov (United States)

Basset, Olivier; Deffert, Christine; Foti, Michelangelo; Bedard, Karen; Jaquet, Vincent; Ogier-Denis, Eric; Krause, Karl-Heinz

2009-10-01

The superoxide-generating NADPH oxidase NOX1 is thought to be involved in signaling by the angiotensin II-receptor AT1R. However, underlying signaling steps are poorly understood. In this study, we investigated the effect of AngII on aortic smooth muscle from wild-type and NOX1-deficient mice. NOX1-deficient cells showed decreased basal ROS generation and did not produce ROS in response to AngII. Unexpectedly, AngII-dependent Ca(2+) signaling was markedly decreased in NOX1-deficient cells. Immunostaining demonstrated that AT1R was localized on the plasma membrane in wild-type, but intracellularly in NOX1-deficient cells. Immunohistochemistry and immunoblotting showed a decreased expression of AT1R in the aorta of NOX1-deficient mice. To investigate the basis of the abnormal AT1R targeting, we studied caveolin expression and phosphorylation. The amounts of total caveolin and of caveolae were not different in NOX1-deficient mice, but a marked decrease occurred in the phosphorylated form of caveolin. Exogenous H(2)O(2) or transfection of a NOX1 plasmid restored AngII responses in NOX1-deficient cells. Based on these findings, we propose that NOX1-derived reactive oxygen species regulate cell-surface expression of AT1R through mechanisms including caveolin phosphorylation. The lack cell-surface AT1R expression in smooth muscle could be involved in the decreased blood pressure in NOX1-deficient mice.

The endoperoxide ascaridol shows strong differential cytotoxicity in nucleotide excision repair-deficient cells

Energy Technology Data Exchange (ETDEWEB)

Abbasi, Rashda [Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Efferth, Thomas [Institute of Pharmacy und Biochemistry, Johannes Gutenberg University, Staudinger Weg 5, 55128 Mainz (Germany); Kuhmann, Christine [Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Opatz, Till [Institute of Organic Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz (Germany); Hao, Xiaojiang [Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204 (China); Popanda, Odilia, E-mail: o.popanda@dkfz.de [Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Schmezer, Peter [Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany)

2012-03-15

Targeting synthetic lethality in DNA repair pathways has become a promising anti-cancer strategy. However little is known about such interactions with regard to the nucleotide excision repair (NER) pathway. Therefore, cell lines with a defect in the NER genes ERCC6 or XPC and their normal counterparts were screened with 53 chemically defined phytochemicals isolated from plants used in traditional Chinese medicine for differential cytotoxic effects. The screening revealed 12 drugs that killed NER-deficient cells more efficiently than proficient cells. Five drugs were further analyzed for IC{sub 50} values, effects on cell cycle distribution, and induction of DNA damage. Ascaridol was the most effective compound with a difference of > 1000-fold in resistance between normal and NER-deficient cells (IC{sub 50} values for cells with deficiency in ERCC6: 0.15 μM, XPC: 0.18 μM, and normal cells: > 180 μM). NER-deficiency combined with ascaridol treatment led to G2/M-phase arrest, an increased percentage of subG1 cells, and a substantially higher DNA damage induction. These results were confirmed in a second set of NER-deficient and -proficient cell lines with isogenic background. Finally, ascaridol was characterized for its ability to generate oxidative DNA damage. The drug led to a dose-dependent increase in intracellular levels of reactive oxygen species at cytotoxic concentrations, but only NER-deficient cells showed a strongly induced amount of 8-oxodG sites. In summary, ascaridol is a cytotoxic and DNA-damaging compound which generates intracellular reactive oxidative intermediates and which selectively affects NER-deficient cells. This could provide a new therapeutic option to treat cancer cells with mutations in NER genes. -- Highlights: ► Thousand-fold higher Ascaridol activity in NER-deficient versus proficient cells. ► Impaired repair of Ascaridol-induced oxidative DNA damage in NER-deficient cells. ► Selective activity of Ascaridol opens new therapy

The endoperoxide ascaridol shows strong differential cytotoxicity in nucleotide excision repair-deficient cells

International Nuclear Information System (INIS)

Abbasi, Rashda; Efferth, Thomas; Kuhmann, Christine; Opatz, Till; Hao, Xiaojiang; Popanda, Odilia; Schmezer, Peter

2012-01-01

Targeting synthetic lethality in DNA repair pathways has become a promising anti-cancer strategy. However little is known about such interactions with regard to the nucleotide excision repair (NER) pathway. Therefore, cell lines with a defect in the NER genes ERCC6 or XPC and their normal counterparts were screened with 53 chemically defined phytochemicals isolated from plants used in traditional Chinese medicine for differential cytotoxic effects. The screening revealed 12 drugs that killed NER-deficient cells more efficiently than proficient cells. Five drugs were further analyzed for IC 50 values, effects on cell cycle distribution, and induction of DNA damage. Ascaridol was the most effective compound with a difference of > 1000-fold in resistance between normal and NER-deficient cells (IC 50 values for cells with deficiency in ERCC6: 0.15 μM, XPC: 0.18 μM, and normal cells: > 180 μM). NER-deficiency combined with ascaridol treatment led to G2/M-phase arrest, an increased percentage of subG1 cells, and a substantially higher DNA damage induction. These results were confirmed in a second set of NER-deficient and -proficient cell lines with isogenic background. Finally, ascaridol was characterized for its ability to generate oxidative DNA damage. The drug led to a dose-dependent increase in intracellular levels of reactive oxygen species at cytotoxic concentrations, but only NER-deficient cells showed a strongly induced amount of 8-oxodG sites. In summary, ascaridol is a cytotoxic and DNA-damaging compound which generates intracellular reactive oxidative intermediates and which selectively affects NER-deficient cells. This could provide a new therapeutic option to treat cancer cells with mutations in NER genes. -- Highlights: ► Thousand-fold higher Ascaridol activity in NER-deficient versus proficient cells. ► Impaired repair of Ascaridol-induced oxidative DNA damage in NER-deficient cells. ► Selective activity of Ascaridol opens new therapy options in

Are mitochondrial reactive oxygen species required for autophagy?

International Nuclear Information System (INIS)

Jiang, Jianfei; Maeda, Akihiro; Ji, Jing; Baty, Catherine J.; Watkins, Simon C.; Greenberger, Joel S.; Kagan, Valerian E.

2011-01-01

Highlights: → Autophageal and apoptotic pathways were dissected in cytochrome c deficient cells. → Staurosporine (STS)-induced autophagy was not accompanied by ROS generation. → Autophagy was detectable in mitochondrial DNA deficient ρ 0 cells. → Mitochondrial ROS are not required for the STS-induced autophagy in HeLa cells. -- Abstract: Reactive oxygen species (ROS) are said to participate in the autophagy signaling. Supporting evidence is obscured by interference of autophagy and apoptosis, whereby the latter heavily relies on ROS signaling. To dissect autophagy from apoptosis we knocked down expression of cytochrome c, the key component of mitochondria-dependent apoptosis, in HeLa cells using shRNA. In cytochrome c deficient HeLa1.2 cells, electron transport was compromised due to the lack of electron shuttle between mitochondrial respiratory complexes III and IV. A rapid and robust LC3-I/II conversion and mitochondria degradation were observed in HeLa1.2 cells treated with staurosporine (STS). Neither generation of superoxide nor accumulation of H 2 O 2 was detected in STS-treated HeLa1.2 cells. A membrane permeable antioxidant, PEG-SOD, plus catalase exerted no effect on STS-induced LC3-I/II conversion and mitochondria degradation. Further, STS caused autophagy in mitochondria DNA-deficient ρ o HeLa1.2 cells in which both electron transport and ROS generation were completely disrupted. Counter to the widespread view, we conclude that mitochondrial ROS are not required for the induction of autophagy.

A theoretical study of stability and vacancy replenishing of MoO{sub 3}(0 1 0) surfaces in oxygen atmosphere

Energy Technology Data Exchange (ETDEWEB)

Lei, Yan-Hua; Chen, Zhao-Xu, E-mail: zxchen@nju.edu.cn

2016-01-15

Graphical abstract: - Highlights: • Under normal experimental conditions perfect surface of MoO{sub 3}(0 1 0) is favorable. • Line defects along asymmetric oxygen direction in lean oxygen condition are favored. • Vacancy replenishing occurs on vacancies formed by terminal and asymmetrical oxygen. - Abstract: Oxygen vacancies on transition metal oxide surfaces are catalytically very important. The stability, shape and replenishing process of the vacancies are critical to understanding reactions happening on the surfaces. In this paper we investigate the stability of various defective MoO{sub 3}(0 1 0) surfaces and examine the influence of environmental oxygen on the stability as well as the active sites for the replenishing process. Our calculations reveal that the line oxygen defect along a (asymmetric oxygen) direction is thermodynamically most favorable at higher defect concentration whereas point defect surfaces are unfavorable. Under normal experimental conditions the perfect surface dominates the MoO{sub 3}(0 1 0). We show that for stoichiometric surfaces of any oxides (A{sub x}O{sub y}) the formation energy per vacancy controls the favorable defect shape (line or point defects). Calculations indicate that O{sub 2} can dissociate readily on the surfaces that double vacancies share one Mo atom. The replenishing process of the oxygen vacancies through O{sub 2} dissociation most likely occurs on the double-vacancy containing one terminal and one asymmetrical oxygen vacancies.

Determination of oxygen content in high T/sub c/ superconductors by a charged particle activation method

International Nuclear Information System (INIS)

Tao, Z.; Alburger, D.E.; Jones, K.W.; Yao, Y.D.; Kao, Y.H.

1988-01-01

A new method for determining the oxygen content in high T/sub c/ superconductors has been demonstrated using a charged particle activation technique. This method allows a measurement of the concentration of 16 O atoms in the superconducting material by detection of the 17 F produced with the 16 O(d,n) 17 F nuclear reaction. By way of example, this technique is applied to the determination of oxygen content in a series of high T/sub c/ Y-Ba-Cu-O samples in which the stoichiometry is varied by reducing the copper concentration. The stabilized oxygen content shows a nonlinear dependence on the copper deficiency in these specimens

Impaired Insulin Signaling is Associated with Hepatic Mitochondrial Dysfunction in IR+/−-IRS-1+/− Double Heterozygous (IR-IRS1dh Mice

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Andras Franko

2017-05-01

Full Text Available Mitochondria play a pivotal role in energy metabolism, but whether insulin signaling per se could regulate mitochondrial function has not been identified yet. To investigate whether mitochondrial function is regulated by insulin signaling, we analyzed muscle and liver of insulin receptor (IR+/−-insulin receptor substrate-1 (IRS-1+/− double heterozygous (IR-IRS1dh mice, a well described model for insulin resistance. IR-IRS1dh mice were studied at the age of 6 and 12 months and glucose metabolism was determined by glucose and insulin tolerance tests. Mitochondrial enzyme activities, oxygen consumption, and membrane potential were assessed using spectrophotometric, respirometric, and proton motive force analysis, respectively. IR-IRS1dh mice showed elevated serum insulin levels. Hepatic mitochondrial oxygen consumption was reduced in IR-IRS1dh animals at 12 months of age. Furthermore, 6-month-old IR-IRS1dh mice demonstrated enhanced mitochondrial respiration in skeletal muscle, but a tendency of impaired glucose tolerance. On the other hand, 12-month-old IR-IRS1dh mice showed improved glucose tolerance, but normal muscle mitochondrial function. Our data revealed that deficiency in IR/IRS-1 resulted in normal or even elevated skeletal muscle, but impaired hepatic mitochondrial function, suggesting a direct cross-talk between insulin signaling and mitochondria in the liver.

Regional gradients in surface sediment nitrogen isotopes as a reflection of nutrient cycling and oxygen deficiency in upwelling areas off Peru and Namibia (Invited)

Science.gov (United States)

Schneider, R. R.; Mollier-Vogel, E.; Martinez, P.

2010-12-01

The sedimentary d15N signal is commonly considered as a reflection of the marine nutrient cycling and related biochemical processes in the overlying water masses. In the modern ocean all processes together result in a mean d15N value of about 5 to 6 per mill for dissolved nitrate. Deviations from this value are considered as a product mainly of nitrogen fixation and nitrate supply causing lower values, while nitrate utilization and denitrification, as well as organic matter degradation tend to shift the signal to higher values. As denitrification is only occurring under conditions of strong oxygen limitation in the water column outstandingly high d15N values in sediment records are commonly taken as indirect evidence for strong oxygen minimum conditions in the past. By comparing surface sediment values from coastal upwelling areas off Namibia and Peru, we test whether such an approach is applicable. Only the Peruvian system is characterized by a pronounced oxygen minimum zone (OMZ) that extends across the shelf and slope far into the Eastern Equatorial Pacific. For comparison we present new results for the Peruvian margin between 2°N and 20°S within and below the Peruvian OMZ in combination with a similar data set from the Namibian margin with an OMZ restricted to the inner shelf. The Peruvian sediment data is furthermore compared to d15N of dissolved nitrate in the overlying water column to better understand how regional oceanography effects the water column d15N and thus the sediment surface signal. Productivity and nitrate uptake is maximal at the position of local and perennial upwelling cells in both systems. However, due to continuous nutrient supply into the upwelling systems sedimentary d15N values on the outer shelves and slopes reveal an increase of only about 2 to 3 per mill over the mean ocean value. Only where extreme oxygen deficiency occurs, as off Peru between 10 and 20 S, the sedimentary d15N signal reaches very high values above 10 per mill

Metazoan meiofauna within the oxygen-minimum zone off Chile: Results of the 2001-PUCK expedition

Science.gov (United States)

Veit-Köhler, Gritta; Gerdes, Dieter; Quiroga, Eduardo; Hebbeln, Dierk; Sellanes, Javier

2009-07-01

A quantitative study of metazoan meiofauna was carried out at continental shelf and slope stations affected by the oxygen-minimum zone in the eastern South Pacific off Chile. Densities of meiobenthos at the investigated stations off Antofagasta (22°S), Concepción (36°S), and Chiloé (42°S) ranged from 1282.1 to 8847.8 ind 10 cm -2. Oxygen deficiency led only to average abundances, despite higher food availability and freshness at the corresponding sites. Sediment organic carbon, chlorophyll- a, and phaeopigment contents were used as measures of the input from water-column primary production, which accumulated at the oxygen-minimum zone stations. The highest abundances were found at a station with an oxygen content of 0.79 mL L -1, which was slightly elevated from what is defined as oxygen minimum (0.5 mL L -1). The most oxygenated site yielded the lowest densities. Meiofauna assemblages became more diverse with increasing bottom-water oxygenation, whereas nematodes were the most abundant taxon at every station, followed by annelids, copepods, and nauplii.

Critical Issues in the Study of Magnesium Transport Systems and Magnesium Deficiency Symptoms in Plants

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Natsuko I. Kobayashi

2015-09-01

Full Text Available Magnesium (Mg is the second most abundant cation in living cells. Over 300 enzymes are known to be Mg-dependent, and changes in the Mg concentration significantly affects the membrane potential. As Mg becomes deficient, starch accumulation and chlorosis, bridged by the generation of reactive oxygen species, are commonly found in Mg-deficient young mature leaves. These defects further cause the inhibition of photosynthesis and finally decrease the biomass. Recently, transcriptome analysis has indicated the transcriptinal downregulation of chlorophyll apparatus at the earlier stages of Mg deficiency, and also the potential involvement of complicated networks relating to hormonal signaling and circadian oscillation. However, the processes of the common symptoms as well as the networks between Mg deficiency and signaling are not yet fully understood. Here, for the purpose of defining the missing pieces, several problems are considered and explained by providing an introduction to recent reports on physiological and transcriptional responses to Mg deficiency. In addition, it has long been unclear whether the Mg deficiency response involves the modulation of Mg2+ transport system. In this review, the current status of research on Mg2+ transport and the relating transporters are also summarized. Especially, the rapid progress in physiological characterization of the plant MRS2 gene family as well as the fundamental investigation about the molecular mechanism of the action of bacterial CorA proteins are described.

Meta-analysis of melanin-concentrating hormone signaling-deficient mice on behavioral and metabolic phenotypes.

Directory of Open Access Journals (Sweden)

Kenkichi Takase

Full Text Available The demand for meta-analyses in basic biomedical research has been increasing because the phenotyping of genetically modified mice does not always produce consistent results. Melanin-concentrating hormone (MCH has been reported to be involved in a variety of behaviors that include feeding, body-weight regulation, anxiety, sleep, and reward behavior. However, the reported behavioral and metabolic characteristics of MCH signaling-deficient mice, such as MCH-deficient mice and MCH receptor 1 (MCHR1-deficient mice, are not consistent with each other. In the present study, we performed a meta-analysis of the published data related to MCH-deficient and MCHR1-deficient mice to obtain robust conclusions about the role of MCH signaling. Overall, the meta-analysis revealed that the deletion of MCH signaling enhanced wakefulness, locomotor activity, aggression, and male sexual behavior and that MCH signaling deficiency suppressed non-REM sleep, anxiety, responses to novelty, startle responses, and conditioned place preferences. In contrast to the acute orexigenic effect of MCH, MCH signaling deficiency significantly increased food intake. Overall, the meta-analysis also revealed that the deletion of MCH signaling suppressed the body weight, fat mass, and plasma leptin, while MCH signaling deficiency increased the body temperature, oxygen consumption, heart rate, and mean arterial pressure. The lean phenotype of the MCH signaling-deficient mice was also confirmed in separate meta-analyses that were specific to sex and background strain (i.e., C57BL/6 and 129Sv. MCH signaling deficiency caused a weak anxiolytic effect as assessed with the elevated plus maze and the open field test but also caused a weak anxiogenic effect as assessed with the emergence test. MCH signaling-deficient mice also exhibited increased plasma corticosterone under non-stressed conditions, which suggests enhanced activity of the hypothalamic-pituitary-adrenal axis. To the best of our

Effect of oxygen on the properties of Y-Ba-CuO ceramics

International Nuclear Information System (INIS)

Nemoshkalenko, V.V.; Ivanov, M.A.; Klimenko, G.A.

1988-01-01

The samples of Y-Ba-CuO ceramics 60x60x60 mm 3 in size were synthesized and investigated with provision for their impurity content, crystallography, superconductive and magnetic properties. The conditions of low temperature thermal treatments, as compared to the sintering ones, are offered that result in degradation of superconductive properties due to partial oxygen removal and their subsequent recovery. The mechanism of copper spin-paramagnetism growth in oxygen-deficient samples is discussed. The intensity of narrow (∼ 3 mrad half-width) component observed in the angular distribution of annihilation photons of partially de-oxygenized sample is found to increase in a constant magnetic field, suggesting the formation of positronium-like states. The intense CuOEH + 2 emission line is shown to be present in the spectra of superconductive samples, while it is absent in the non-superconductive state

Radiation protection of glutathion-deficient cells by thiol-containing compounds

International Nuclear Information System (INIS)

Ehdgren, M.; Modig, Kh.; Revez, L.

1983-01-01

Results of the experiments on the effect of aminothiols (under conditions of hypoxia and in the air) on radiation injury of glutathion-deficient human fibroblasts (criterionthe number of single-strand breaks in DNA) have been interpreted in the following way protection with eddogenous and exogenous aminothiols takes place to a great extent due to repair of radiation induced radicals by means of hydrogen loss by SH-group under conditions of competition with oxygen which registers the radiation injury. Repair of in uries formed under aeration conditions is accelerated by endogenoUs and exogenous aminothiols

Rf-sputtered vanadium oxide thin films: effect of oxygen partial pressure on structural and electrochemical properties

CERN Document Server

Park, Y J; Ryu, K S; Chang, S H; Park, S C; Yoon, S M; Kim, D K

2001-01-01

Vanadium oxide thin films with thickness of about 2000 A have been prepared by radio frequency sputter deposition using a V sub 2 O sub 5 target in a mixed argon and oxygen atmosphere with different Ar/O sub 2 ratio ranging from 99/1 to 90/10. X-ray diffraction and X-ray absorption near edge structure spectroscopic studies show that the oxygen content higher than 5% crystallizes a stoichiometric V sub O sub 5 phase, while oxygen deficient phase is formed in the lower oxygen content. The oxygen content in the mixed Ar + O sub 2 has a significant influence on electrochemical lithium insertion/deinsertion property. The discharge-charge capacity of vanadium oxide film increases with increasing the reactive oxygen content. The V sub O sub 5 film deposited at the Ar/O sub 2 ratio of 90/10 exhibits high discharge capacity of 100 mu Ah/cm sup 2 -mu m along with good cycle performance.

Angiotensin II type 1a receptor-deficient mice develop angiotensin II-induced oxidative stress and DNA damage without blood pressure increase.

Science.gov (United States)

Zimnol, Anna; Amann, Kerstin; Mandel, Philipp; Hartmann, Christina; Schupp, Nicole

2017-12-01

Hypertensive patients have an increased risk of developing kidney cancer. We have shown in vivo that besides elevating blood pressure, angiotensin II causes DNA damage dose dependently. Here, the role of blood pressure in the formation of DNA damage is studied. Mice lacking one of the two murine angiotensin II type 1 receptor (AT1R) subtypes, AT1aR, were equipped with osmotic minipumps, delivering angiotensin II during 28 days. Parameters of oxidative stress and DNA damage of kidneys and hearts of AT1aR-knockout mice were compared with wild-type (C57BL/6) mice receiving angiotensin II, and additionally, with wild-type mice treated with candesartan, an antagonist of both AT1R subtypes. In wild-type mice, angiotensin II induced hypertension, reduced kidney function, and led to a significant formation of reactive oxygen species (ROS). Furthermore, genomic damage was markedly increased in this group. All these responses to angiotensin II could be attenuated by concurrent administration of candesartan. In AT1aR-deficient mice treated with angiotensin II, systolic pressure was not increased, and renal function was not affected. However, angiotensin II still led to an increase of ROS in kidneys and hearts of these animals. Additionally, genomic damage in the form of double-strand breaks was significantly induced in kidneys of AT1aR-deficient mice. Our results show that angiotensin II induced ROS production and DNA damage even without the presence of AT1aR and independently of blood pressure changes. Copyright © 2017 the American Physiological Society.

Dissimilatory nitrate reduction by Aspergillus terreus isolated from the seasonal oxygen minimum zone in the Arabian Sea

NARCIS (Netherlands)

Stief, Peter; Fuchs-Ocklenburg, Silvia; Kamp, Anja; Manohar, Cathrine-Sumathi; Houbraken, Jos; Boekhout, Teun; de Beer, Dirk; Stoeck, Thorsten

2014-01-01

BACKGROUND: A wealth of microbial eukaryotes is adapted to life in oxygen-deficient marine environments. Evidence is accumulating that some of these eukaryotes survive anoxia by employing dissimilatory nitrate reduction, a strategy that otherwise is widespread in prokaryotes. Here, we report on the

Vitamin D deficiency rickets in an adolescent with severe atopic dermatitis.

Science.gov (United States)

Borzutzky, Arturo; Grob, Francisca; Camargo, Carlos A; Martinez-Aguayo, Alejandro

2014-02-01

Atopic dermatitis (AD) affects 10% to 20% of children worldwide. Its severity may be inversely correlated with 25-hydroxyvitamin D (25OHD) levels. Although low levels of vitamin D (VD) can cause rickets in infants, VD deficiency rickets is an unusual presentation in teenagers. We report the case of a 14-year-old girl with severe AD and fish allergy since early childhood. She lived at high latitude (with less sun exposure) and, because of her atopic disorders, avoided sunlight and fish. Laboratory studies showed elevated alkaline phosphatase and parathyroid hormone levels and low serum calcium; her serum 25OHD level was rickets due to VD deficiency. Treatment with VD increased her 25OHD level to 44 nmol/L, with normalization of alkaline phosphatase, parathyroid hormone, and calcium. Moreover, we observed a dramatic improvement in her AD severity with VD treatment. This case demonstrates the complex interaction between VD deficiency, AD, and food allergy. We advise a high index of suspicion of VD deficiency rickets in children of all ages with AD, particularly during accelerated growth periods and in the presence of other risk factors such as darker skin, living at high latitude, sun avoidance, and low intake of VD-rich foods. The concomitant improvement in bone-related parameters and AD severity may reflect a double benefit of VD treatment, a possibility that warrants research on VD as potential treatment for AD.

Photo-excitation of carotenoids causes cytotoxicity via singlet oxygen production

International Nuclear Information System (INIS)

Yoshii, Hiroshi; Yoshii, Yukie; Asai, Tatsuya; Furukawa, Takako; Takaichi, Shinichi; Fujibayashi, Yasuhisa

2012-01-01

Highlights: ► Some photo-excited carotenoids have photosensitizing ability. ► They are able to produce ROS. ► Photo-excited fucoxanthin can produce singlet oxygen through energy transfer. -- Abstract: Carotenoids, natural pigments widely distributed in algae and plants, have a conjugated double bond system. Their excitation energies are correlated with conjugation length. We hypothesized that carotenoids whose energy states are above the singlet excited state of oxygen (singlet oxygen) would possess photosensitizing properties. Here, we demonstrated that human skin melanoma (A375) cells are damaged through the photo-excitation of several carotenoids (neoxanthin, fucoxanthin and siphonaxanthin). In contrast, photo-excitation of carotenoids that possess energy states below that of singlet oxygen, such as β-carotene, lutein, loroxanthin and violaxanthin, did not enhance cell death. Production of reactive oxygen species (ROS) by photo-excited fucoxanthin or neoxanthin was confirmed using a reporter assay for ROS production with HeLa Hyper cells, which express a fluorescent indicator protein for intracellular ROS. Fucoxanthin and neoxanthin also showed high cellular penetration and retention. Electron spin resonance spectra using 2,2,6,6-tetramethil-4-piperidone as a singlet oxygen trapping agent demonstrated that singlet oxygen was produced via energy transfer from photo-excited fucoxanthin to oxygen molecules. These results suggest that carotenoids such as fucoxanthin, which are capable of singlet oxygen production through photo-excitation and show good penetration and retention in target cells, are useful as photosensitizers in photodynamic therapy for skin disease.

Vitamin Deficiency Anemia

Science.gov (United States)

... are unique to specific vitamin deficiencies. Folate-deficiency anemia risk factors include: Undergoing hemodialysis for kidney failure. ... the metabolism of folate. Vitamin B-12 deficiency anemia risk factors include: Lack of intrinsic factor. Most ...

26 CFR 1.6165-1 - Bonds where time to pay the tax or deficiency has been extended.

Science.gov (United States)

2010-04-01

... exceeding double the amount of the tax with respect to which the extension is granted. Such bond shall be... 26 Internal Revenue 13 2010-04-01 2010-04-01 false Bonds where time to pay the tax or deficiency... THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES Extensions of Time for Payment § 1.6165-1...

Genetic control of yeast cell radiosensitivity modification by oxygen and hypoxic sensitizers

International Nuclear Information System (INIS)

Zhuranovskaya, G.P.; Petin, V.G.

1984-01-01

Diploid yeast cells Saccharomyces cerevisiae ''of the wild type'', individual mutants, homozygous in rad 2 and rad 54 and double mutants, containing both these loci in homozygous state are considered to prove genetic determination of radiosensitivity modification of hypoxic cells by oxygen and electron acceptor compounds previously demonstrated on yeast cells of other genotypes. It is shown that both ''oxygen effect'' and the effect of hypoxic sensitizers depend on the activity of repair systems. The possible mechanism of participation of post-radiation restoration processes in the modification of cell radiosensitivity, is discussed

Homogeneous double-layer amorphous Si-doped indium oxide thin-film transistors for control of turn-on voltage

International Nuclear Information System (INIS)

Kizu, Takio; Tsukagoshi, Kazuhito; Aikawa, Shinya; Nabatame, Toshihide; Fujiwara, Akihiko; Ito, Kazuhiro; Takahashi, Makoto

2016-01-01

We fabricated homogeneous double-layer amorphous Si-doped indium oxide (ISO) thin-film transistors (TFTs) with an insulating ISO cap layer on top of a semiconducting ISO bottom channel layer. The homogeneously stacked ISO TFT exhibited high mobility (19.6 cm"2/V s) and normally-off characteristics after annealing in air. It exhibited normally-off characteristics because the ISO insulator suppressed oxygen desorption, which suppressed the formation of oxygen vacancies (V_O) in the semiconducting ISO. Furthermore, we investigated the recovery of the double-layer ISO TFT, after a large negative shift in turn-on voltage caused by hydrogen annealing, by treating it with annealing in ozone. The recovery in turn-on voltage indicates that the dense V_O in the semiconducting ISO can be partially filled through the insulator ISO. Controlling molecule penetration in the homogeneous double layer is useful for adjusting the properties of TFTs in advanced oxide electronics.

High-pressure BaCrO_3 polytypes and the 5H–BaCrO_2_._8 phase

International Nuclear Information System (INIS)

Arévalo-López, Angel M.; Paul Attfield, J.

2015-01-01

Polytypism of BaCrO_3 perovskites has been investigated at 900–1100 °C and pressures up to 22 GPa. Hexagonal 5H, 4H, and 6H perovskites are observed with increasing pressure, and the cubic 3C perovskite (a=3.99503(1) Å) is observed in bulk form for the first time at 19–22 GPa. An oxygen-deficient material with limiting composition 5H–BaCrO_2_._8 is synthesised at 1200 °C under ambient pressure. This contains double tetrahedral Cr"4"+ layers and orders antiferromagnetically below 260 K with a (0 0 1/2) magnetic structure. - Graphical abstract: Hexagonal 5H, 4H, and 6H perovskites polytypes of BaCrO_3 are observed with increasing pressure and the cubic 3C perovskite is stabilised in bulk form for the first time at 19–22 GPa. Oxygen-deficient 5H–BaCrO_2_._8 synthesised at ambient pressure contains double tetrahedral Cr"4"+ layers and orders antiferromagnetically below 260 K with a (0 0 1/2) magnetic structure.

SrRuO3 thin films grown on MgO substrates at different oxygen partial pressures

KAUST Repository

Zou, Bin

2013-01-08

A comprehensive study of SrRuO3 thin films growth on (001) MgO substrates by pulsed laser deposition in a wide oxygen pressure range from 10 to 300 mTorr was carried out. The experimental results showed a correlation between the lattice constants, resistivity, and oxygen partial pressures used. Ru deficiency detected only in films deposited at lower oxygen pressures (<50 mTorr), resulted in an elongation of the in-plane and out-of-plane lattice constants and an increase in the film resistivity. When deposited with oxygen partial pressure of 50 mTorr, SrRuO3 films had lattice parameters matching those of bulk SrRuO3 material and exhibited room temperature resistivity of 320 μΩ·cm. The resistivity of SrRuO 3/MgO films decreased with increasing oxygen partial pressure. Copyright © 2013 Materials Research Society.

Iron-Deficiency Anemia

Medline Plus

Full Text Available ... to moderate iron-deficiency anemia, or red blood cell transfusion for severe iron-deficiency anemia. You may ... body needs iron to make healthy red blood cells. Iron-deficiency anemia usually develops over time because ...

Iron-Deficiency Anemia

Medline Plus

Full Text Available ... you are diagnosed with iron-deficiency anemia. Risk Factors You may have an increased risk for iron- ... iron-deficiency anemia if you have certain risk factors , including pregnancy. To prevent iron-deficiency anemia, your ...

Imprint and oxygen deficiency in (Pb,La)(Zr,Ti)O3 thin-film capacitors with La-Sr-Co-O electrodes

International Nuclear Information System (INIS)

Lee, J.; Ramesh, R.; Keramidas, V.G.; Warren, W.L.; Pike, G.E.; Evans, J.T. Jr.

1995-01-01

La-Sr-Co-O/Pb-La-Zr-Ti-O/La-Sr-Co-O thin-film capacitors have been grown in various oxygen ambients by pulsed laser deposition. As the oxygen ambient became more reducing, the capacitors developed more voltage asymmetry in hysteresis loops and a more preferred polarization state directed towards the top electrode. PLZT capacitors cooled in a fully oxidizing atmosphere (i.e., 1 atm oxygen pressure) exhibited nominally symmetric hysteresis loops and also showed little imprint both with and without fully saturating bias fields. We find that ambient oxygen pressure is an important process parameter and the imprint behavior is closely related with ambient oxygen induced effects such as oxygen vacancies, its related defect-dipole complexes and trapping of free charges. The different imprint behavior under negative and positive bias also suggests that the dipolar-defect complexes tend to cause imprint in PLZT capacitors

What Are Rare Clotting Factor Deficiencies?

Science.gov (United States)

... Deficiency Factor V Deficiency Combined FV & FVIII Deficiencies Factor VII Deficiency Factor X Deficiency Factor XI Deficiency Factor ... Deficiency Factor V Deficiency Combined FV & FVIII Deficiencies Factor VII Deficiency Factor X Deficiency Factor XI Deficiency Factor ...

Does Vitamin C Deficiency Promote Fatty Liver Disease Development?

Directory of Open Access Journals (Sweden)

David Højland Ipsen

2014-12-01

Full Text Available Obesity and the subsequent reprogramming of the white adipose tissue are linked to human disease-complexes including metabolic syndrome and concurrent non-alcoholic fatty liver disease (NAFLD and non-alcoholic steatohepatitis (NASH. The dietary imposed dyslipidemia promotes redox imbalance by the generation of excess levels of reactive oxygen species and induces adipocyte dysfunction and reprogramming, leading to a low grade systemic inflammation and ectopic lipid deposition, e.g., in the liver, hereby promoting a vicious circle in which dietary factors initiate a metabolic change that further exacerbates the negative consequences of an adverse life-style. Large epidemiological studies and findings from controlled in vivo animal studies have provided evidence supporting an association between poor vitamin C (VitC status and propagation of life-style associated diseases. In addition, overweight per se has been shown to result in reduced plasma VitC, and the distribution of body fat in obesity has been shown to have an inverse relationship with VitC plasma levels. Recently, a number of epidemiological studies have indicated a VitC intake below the recommended daily allowance (RDA in NAFLD-patients, suggesting an association between dietary habits, disease and VitC deficiency. In the general population, VitC deficiency (defined as a plasma concentration below 23 μM affects around 10% of adults, however, this prevalence is increased by an adverse life-style, deficiency potentially playing a broader role in disease progression in specific subgroups. This review discusses the currently available data from human surveys and experimental models in search of a putative role of VitC deficiency in the development of NAFLD and NASH.

Iron-Deficiency Anemia

Medline Plus

Full Text Available ... for iron-deficiency anemia if you have certain risk factors , including pregnancy. To prevent iron-deficiency anemia, your doctor may recommend you eat heart-healthy foods or control other conditions that can cause iron-deficiency anemia. ...

Iron-Deficiency Anemia

Medline Plus

Full Text Available ... Home / < Back To Health Topics / Iron-Deficiency Anemia Iron-Deficiency Anemia Also known as Leer en español ... bleeding Consuming less than recommended daily amounts of iron Iron-deficiency anemia can be caused by getting ...

Idh2 Deficiency Exacerbates Acrolein-Induced Lung Injury through Mitochondrial Redox Environment Deterioration

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Jung Hyun Park

2017-01-01

Full Text Available Acrolein is known to be involved in acute lung injury and other pulmonary diseases. A number of studies have suggested that acrolein-induced toxic effects are associated with depletion of antioxidants, such as reduced glutathione and protein thiols, and production of reactive oxygen species. Mitochondrial NADP+-dependent isocitrate dehydrogenase (idh2 regulates mitochondrial redox balance and reduces oxidative stress-induced cell injury via generation of NADPH. Therefore, we evaluated the role of idh2 in acrolein-induced lung injury using idh2 short hairpin RNA- (shRNA- transfected Lewis lung carcinoma (LLC cells and idh2-deficient (idh2−/− mice. Downregulation of idh2 expression increased susceptibility to acrolein via induction of apoptotic cell death due to elevated mitochondrial oxidative stress. Idh2 deficiency also promoted acrolein-induced lung injury in idh2 knockout mice through the disruption of mitochondrial redox status. In addition, acrolein-induced toxicity in idh2 shRNA-transfected LLC cells and in idh2 knockout mice was ameliorated by the antioxidant, N-acetylcysteine, through attenuation of oxidative stress resulting from idh2 deficiency. In conclusion, idh2 deficiency leads to mitochondrial redox environment deterioration, which causes acrolein-mediated apoptosis of LLC cells and acrolein-induced lung injury in idh2−/− mice. The present study supports the central role of idh2 deficiency in inducing oxidative stress resulting from acrolein-induced disruption of mitochondrial redox status in the lung.

Idh2 Deficiency Exacerbates Acrolein-Induced Lung Injury through Mitochondrial Redox Environment Deterioration.

Science.gov (United States)

Park, Jung Hyun; Ku, Hyeong Jun; Lee, Jin Hyup; Park, Jeen-Woo

2017-01-01

Acrolein is known to be involved in acute lung injury and other pulmonary diseases. A number of studies have suggested that acrolein-induced toxic effects are associated with depletion of antioxidants, such as reduced glutathione and protein thiols, and production of reactive oxygen species. Mitochondrial NADP + -dependent isocitrate dehydrogenase ( idh2 ) regulates mitochondrial redox balance and reduces oxidative stress-induced cell injury via generation of NADPH. Therefore, we evaluated the role of idh2 in acrolein-induced lung injury using idh2 short hairpin RNA- (shRNA-) transfected Lewis lung carcinoma (LLC) cells and idh2 -deficient ( idh2 -/- ) mice. Downregulation of idh2 expression increased susceptibility to acrolein via induction of apoptotic cell death due to elevated mitochondrial oxidative stress. Idh2 deficiency also promoted acrolein-induced lung injury in idh2 knockout mice through the disruption of mitochondrial redox status. In addition, acrolein-induced toxicity in idh2 shRNA-transfected LLC cells and in idh2 knockout mice was ameliorated by the antioxidant, N-acetylcysteine, through attenuation of oxidative stress resulting from idh2 deficiency. In conclusion, idh2 deficiency leads to mitochondrial redox environment deterioration, which causes acrolein-mediated apoptosis of LLC cells and acrolein-induced lung injury in idh2 -/- mice. The present study supports the central role of idh2 deficiency in inducing oxidative stress resulting from acrolein-induced disruption of mitochondrial redox status in the lung.

Type I IFN-related NETosis in ataxia telangiectasia and Artemis deficiency.

Science.gov (United States)

Gul, Ersin; Sayar, Esra Hazar; Gungor, Bilgi; Eroglu, Fehime Kara; Surucu, Naz; Keles, Sevgi; Guner, Sukru Nail; Findik, Siddika; Alpdundar, Esin; Ayanoglu, Ihsan Cihan; Kayaoglu, Basak; Geckin, Busra Nur; Sanli, Hatice Asena; Kahraman, Tamer; Yakicier, Cengiz; Muftuoglu, Meltem; Oguz, Berna; Cagdas Ayvaz, Deniz Nazire; Gursel, Ihsan; Ozen, Seza; Reisli, Ismail; Gursel, Mayda

2017-11-16

Pathological inflammatory syndromes of unknown etiology are commonly observed in ataxia telangiectasia (AT) and Artemis deficiency. Similar inflammatory manifestations also exist in patients with STING-associated vasculopathy in infancy (SAVI). We sought to test the hypothesis that the inflammation-associated manifestations observed in patients with AT and Artemis deficiency stem from increased type I IFN signature leading to neutrophil-mediated pathological damage. Cytokine/protein signatures were determined by ELISA, cytometric bead array, or quantitative PCR. Stat1 phosphorylation levels were determined by flow cytometry. DNA species accumulating in the cytosol of patients' cells were quantified microscopically and flow cytometrically. Propensity of isolated polymorhonuclear granulocytes to form neutrophil extracellular traps (NETs) was determined using fluorescence microscopy and picogreen assay. Neutrophil reactive oxygen species levels and mitochondrial stress were assayed using fluorogenic probes, microscopy, and flow cytometry. Type I and III IFN signatures were elevated in plasma and peripheral blood cells of patients with AT, Artemis deficiency, and SAVI. Chronic IFN production stemmed from the accumulation of DNA in the cytoplasm of AT and Artemis-deficient cells. Neutrophils isolated from patients spontaneously produced NETs and displayed indicators of oxidative and mitochondrial stress, supportive of their NETotic tendencies. A similar phenomenon was also observed in neutrophils from healthy controls exposed to patient plasma samples or exogeneous IFN-α. Type I IFN-mediated neutrophil activation and NET formation may contribute to inflammatory manifestations observed in patients with AT, Artemis deficiency, and SAVI. Thus, neutrophils represent a promising target to manage inflammatory syndromes in diseases with active type I IFN signature. Copyright © 2017 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights

Arabidopsis Glutaredoxin S17 Contributes to Vegetative Growth, Mineral Accumulation, and Redox Balance during Iron Deficiency

Directory of Open Access Journals (Sweden)

Han Yu

2017-06-01

Full Text Available Iron (Fe is an essential mineral nutrient and a metal cofactor required for many proteins and enzymes involved in the processes of DNA synthesis, respiration, and photosynthesis. Iron limitation can have detrimental effects on plant growth and development. Such effects are mediated, at least in part, through the generation of reactive oxygen species (ROS. Thus, plants have evolved a complex regulatory network to respond to conditions of iron limitations. However, the mechanisms that couple iron deficiency and oxidative stress responses are not fully understood. Here, we report the discovery that an Arabidopsis thaliana monothiol glutaredoxin S17 (AtGRXS17 plays a critical role in the plants ability to respond to iron deficiency stress and maintain redox homeostasis. In a yeast expression assay, AtGRXS17 was able to suppress the iron accumulation in yeast ScGrx3/ScGrx4 mutant cells. Genetic analysis indicated that plants with reduced AtGRXS17 expression were hypersensitive to iron deficiency and showed increased iron concentrations in mature seeds. Disruption of AtGRXS17 caused plant sensitivity to exogenous oxidants and increased ROS production under iron deficiency. Addition of reduced glutathione rescued the growth and alleviates the sensitivity of atgrxs17 mutants to iron deficiency. These findings suggest AtGRXS17 helps integrate redox homeostasis and iron deficiency responses.

Are mitochondrial reactive oxygen species required for autophagy?

Energy Technology Data Exchange (ETDEWEB)

Jiang, Jianfei, E-mail: jjf73@pitt.edu [Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh (United States); Maeda, Akihiro; Ji, Jing [Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh (United States); Baty, Catherine J.; Watkins, Simon C. [Center for Biologic Imaging, Department of Cell Biology and Physiology, University of Pittsburgh (United States); Greenberger, Joel S. [Department of Radiation Oncology, University of Pittsburgh (United States); Kagan, Valerian E., E-mail: kagan@pitt.edu [Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh (United States)

2011-08-19

Highlights: {yields} Autophageal and apoptotic pathways were dissected in cytochrome c deficient cells. {yields} Staurosporine (STS)-induced autophagy was not accompanied by ROS generation. {yields} Autophagy was detectable in mitochondrial DNA deficient {rho}{sup 0} cells. {yields} Mitochondrial ROS are not required for the STS-induced autophagy in HeLa cells. -- Abstract: Reactive oxygen species (ROS) are said to participate in the autophagy signaling. Supporting evidence is obscured by interference of autophagy and apoptosis, whereby the latter heavily relies on ROS signaling. To dissect autophagy from apoptosis we knocked down expression of cytochrome c, the key component of mitochondria-dependent apoptosis, in HeLa cells using shRNA. In cytochrome c deficient HeLa1.2 cells, electron transport was compromised due to the lack of electron shuttle between mitochondrial respiratory complexes III and IV. A rapid and robust LC3-I/II conversion and mitochondria degradation were observed in HeLa1.2 cells treated with staurosporine (STS). Neither generation of superoxide nor accumulation of H{sub 2}O{sub 2} was detected in STS-treated HeLa1.2 cells. A membrane permeable antioxidant, PEG-SOD, plus catalase exerted no effect on STS-induced LC3-I/II conversion and mitochondria degradation. Further, STS caused autophagy in mitochondria DNA-deficient {rho}{sup o} HeLa1.2 cells in which both electron transport and ROS generation were completely disrupted. Counter to the widespread view, we conclude that mitochondrial ROS are not required for the induction of autophagy.

A brief clinical case of monitoring of oxygenator performance and patient-machine interdependency during prolonged veno-venous extracorporeal membrane oxygenation.

Science.gov (United States)

Belliato, Mirko; Degani, Antonella; Buffa, Antonino; Sciutti, Fabio; Pagani, Michele; Pellegrini, Carlo; Iotti, Giorgio Antonio

2017-10-01

Monitoring veno-venous extracorporeal membrane oxygenation (vvECMO) during 76 days of continuous support in a 42-years old patient with end-stage pulmonary disease, listed for double-lung transplantation. Applying a new monitor (Landing ® , Eurosets, Medolla, Italy) and describing how measured and calculated parameters can be used to understand the variable interdependency between artificial membrane lung (ML) and patient native lung (NL). During vvECMO, in order to understand how the respiratory function is shared between ML and NL, ideally we should obtain data about oxygen transfer and CO 2 removal, both by ML and NL. Measurements for NL can be made on the mechanical ventilator. Measurements for ML are typically made from gas analysis on blood samples drawn from the ECMO system before and after the oxygenator, and therefore are non-continuous. Differently, the Landing monitor provides a continuous measurement of the oxygen transfer from the ML, combined with hemoglobin level, saturation of drained blood and saturation of reinfused blood. Moreover, the Landing monitor provides hemodynamics data about circulation through the ECMO system, with blood flow, pre-oxygenator pressure and post-oxygenator pressure. Of note, measurements include the drain negative pressure, whose monitoring may be particularly useful to prevent hemolysis. Real-time monitoring of vvECMO provides data helpful to understand the complex picture of a patient with severely damaged lungs on one side and an artificial lung on the other side. Data from vvECMO monitoring may help to adapt the settings of both mechanical ventilator and vvECMO. Data about oxygen transfer by the oxygenator are important to evaluate the performance of the device and may help to avoid unnecessary replacements, thus reducing risks and costs.

Altered balance of vasoactive systems in experimental hypertension: The role of relative NO deficiency

Czech Academy of Sciences Publication Activity Database

Kuneš, Jaroslav; Hojná, Silvie; Kadlecová, Michaela; Dobešová, Zdenka; Rauchová, Hana; Vokurková, Martina; Loukotová, Jana; Pecháňová, Olga; Zicha, Josef

2004-01-01

Roč. 53, Suppl.1 (2004), s. S23-S34 ISSN 0862-8408 R&D Projects: GA ČR GA305/03/0769; GA ČR GP305/02/P066; GA AV ČR IAA7011805; GA MŠk LN00A069 Institutional research plan: CEZ:AV0Z5011922 Keywords : NO deficiency * reactive oxygen species * calcium influx Subject RIV: ED - Physiology Impact factor: 1.140, year: 2004

Iron-Deficiency Anemia

Medline Plus

Full Text Available ... anemia, your doctor may order the following blood tests to diagnose iron-deficiency anemia: Complete blood count (CBC) to ... than normal when viewed under a microscope. Different tests help your doctor diagnose iron-deficiency anemia. In iron-deficiency anemia, blood ...

Processing and characterization of Sr{sub 2−x}VMoO{sub 6−δ} double perovskites

Energy Technology Data Exchange (ETDEWEB)

Weisentein, A.J., E-mail: a.weisenstein@gmail.com [Department of Mechanical and Industrial Engineering, Montana State University, Bozeman, MT 59717-3800 (United States); Childs, N., E-mail: nick.childs@msu.montana.edu [Department of Physics, Montana State University, Bozeman, MT 59717-3804 (United States); Amendola, R., E-mail: roberta.amendola@coe.montana.edu [Department of Chemical and Biological Engineering, Montana State University, Bozeman, MT 59717-3920 (United States); Driscoll, D., E-mail: davidrobertdriscoll@gmail.com [Department of Mechanical and Industrial Engineering, Montana State University, Bozeman, MT 59717-3800 (United States); Sofie, S.W., E-mail: ssofie@me.montana.edu [Department of Mechanical and Industrial Engineering, Montana State University, Bozeman, MT 59717-3800 (United States); Gannon, P., E-mail: pgannon@coe.montana.edu [Department of Chemical and Biological Engineering, Montana State University, Bozeman, MT 59717-3920 (United States); Smith, R., E-mail: smith@physics.montana.edu [Department of Physics, Montana State University, Bozeman, MT 59717-3804 (United States)

2013-05-15

In this study, the analysis and characterization of the processing and sintering of Sr{sub 2−x}VMoO{sub 6−δ} perovskites, where x = 0.0, 0.1 and 0.2, was investigated with application potential in high temperature fuel cell electrodes and electro-catalysts. Sr{sub 2−x}VMoO{sub 6−δ} substrates were sintered in a reducing (5%H{sub 2} 95%N{sub 2}) atmosphere at 1100 °C, 1200 °C, and 1300 °C. The X-ray diffraction patterns indicate that the double perovskite is the primary phase for Sr{sub 2−x}VMoO{sub 6−δ} pellets sintered at 1200 °C and 1300 °C for 20 h; however, these pellets show a secondary phase of SrMoO{sub 4−δ}. X-ray photoelectron spectroscopy revealed a deficiency of vanadium on the pellet surfaces, in which samples yielded surface vanadium concentrations of less than 5%. The vanadium inhomogeneity can be explained by the formation of the SrMoO{sub 4−δ} scheelite phase (ABO{sub 4}) due to oxygen exposure on the surface of the pellets, which indicates inward vanadium migration to the bulk, and was exhibited in redox cycling. Sr{sub 2−x}VMoO{sub 6−δ} pellets sintered at 1300 °C showed the lowest resistivity at both SOFC operating temperature (800 °C) and room temperature. The resistivity tests also show a semiconductor to metallic transition for all double perovskites, from heating up to 800 °C to cooling down to room temperature in a reducing atmosphere, related to the reduction of Mo{sup 6+} to Mo{sup 4+}. - Highlights: ► Primary Sr{sub 2−x}VMoO{sub 6−δ} phase only shown to form in excess of 1300 °C in reducing. ► Surface formation of secondary phase SrMoO{sub 4−δ} (Mo{sup 6+}) observed at RT in air. ► Surface vanadium deficiency induced by inward atomic diffusion. ► Semiconductor to metallic transition is related to the reduction of Mo{sup 6+} to Mo{sup 4+}.

Reduced prostasin (CAP1/PRSS8) activity eliminates HAI-1 and HAI-2 deficiency-associated developmental defects by preventing matriptase activation

DEFF Research Database (Denmark)

Szabo, Roman; Uzzun Sales, Katiuchia; Kosa, Peter

2012-01-01

is a critical developmental target for both protease inhibitors. Here, we performed a genetic epistasis analysis to identify additional components of this pathway by generating mice with combined deficiency in either HAI-1 or HAI-2, along with genes encoding developmentally co-expressed candidate matriptase......-prostasin activity causes developmental failure independent of aberrant c-Met and PAR-2 signaling or impaired epithelial sodium transport. Furthermore, phenotypic analysis of PAR-1 and matriptase double-deficient embryos suggests that the protease may not be critical for focal proteolytic activation of PAR-2 during...

Health Deficiencies

Data.gov (United States)

U.S. Department of Health & Human Services — A list of all health deficiencies currently listed on Nursing Home Compare, including the nursing home that received the deficiency, the associated inspection date,...

Mulheres com deficiência e sua dupla vulnerabilidade: contribuições para a construção da integralidade em saúde Women with disabilities and their double vulnerability: contributions for setting up comprehensive health care practices

Directory of Open Access Journals (Sweden)

José Ricardo de Carvalho Mesquita Ayres

2013-03-01

Full Text Available Mulheres com deficiência contam com ações inexpressivas nos serviços de atenção básica em saúde, que embora historicamente privilegiem a clientela feminina, pouco reconhecem os aspectos relativos aos direitos sexuais e reprodutivos e à dupla vulnerabilidade que as acometem por serem mulheres e portarem deficiências. Este estudo é parte de uma pesquisa qualitativa que objetiva identificar dimensões individuais, sociais e programáticas da dupla vulnerabilidade de quinze mulheres com diferentes tipos e graus de deficiência, usuárias de três serviços de atenção básica em saúde na cidade de São Paulo. Destacam-se em suas narrativas vivências de rejeição ou superproteção familiar, dificuldades em adquirir equipamentos para sua autonomia, pouco investimento no estudo e na qualificação profissional, menor participação social, obstáculos à vivencia da sexualidade e da maternidade, falta de acessibilidade física, comunicacional e atitudes pouco receptivas nos serviços de saúde, caracterizando total vulnerabilidade. Problematizá-la possibilita a construção de práticas integrais de saúde que incorporem a dimensão dos direitos humanos de grupos que historicamente experimentam a violação dos mesmos: mulheres e pessoas com deficiência.Women with disabilities have few measures geared to their needs in the primary health care services. Despite the attention given to the female population in these facilities, they still fail to address specificities of women with disabilities, such as issues related to their sexual and reproductive rights and their double vulnerability, both as women and as disabled individuals. This research is part of a qualitative study to identify the individual, social and programmed double vulnerability of fifteen women with different types and degrees of disabilities, who are frequenters of three primary health care facilities in São Paulo city. The women's narratives highlighted experiences of

Novel roles of folic acid as redox regulator: Modulation of reactive oxygen species sinker protein expression and maintenance of mitochondrial redox homeostasis on hepatocellular carcinoma.

Science.gov (United States)

Lai, Kun-Goung; Chen, Chi-Fen; Ho, Chun-Te; Liu, Jun-Jen; Liu, Tsan-Zon; Chern, Chi-Liang

2017-06-01

We provide herein several lines of evidence to substantiate that folic acid (or folate) is a micronutrient capable of functioning as a novel redox regulator on hepatocellular carcinoma. First, we uncovered that folate deficiency could profoundly downregulate two prominent anti-apoptotic effectors including survivin and glucose-regulated protein-78. Silencing of either survivin or glucose-regulated protein-78 via small interfering RNA interfering technique established that both effectors could serve as reactive oxygen species sinker proteins. Second, folate deficiency-triggered oxidative-nitrosative stress could strongly induce endoplasmic reticulum stress that in turn could provoke cellular glutathione depletion through the modulation of the following two crucial events: (1) folate deficiency could strongly inhibit Bcl-2 expression leading to severe suppression of the mitochondrial glutathione pool and (2) folate deficiency could also profoundly inhibit two key enzymes that governing cellular glutathione redox regulation including γ-glutamylcysteinyl synthetase heavy chain, a catalytic enzyme for glutathione biosynthesis, and mitochondrial isocitrate dehydrogenase 2, an enzyme responsible for providing nicotinamide adenine dinucleotide phosphate necessary for regenerating oxidized glutathione disulfide back to glutathione via mitochondrial glutathione reductase. Collectively, we add to the literature new data to strengthen the notion that folate is an essential micronutrient that confers a novel role to combat reactive oxygen species insults and thus serves as a redox regulator via upregulating reactive oxygen species sinker proteins and averting mitochondrial glutathione depletion through proper maintenance of redox homeostasis via positively regulating glutathione biosynthesis, glutathione transporting system, and mitochondrial glutathione recycling process.

Iron-Deficiency Anemia

Medline Plus

Full Text Available ... if you are diagnosed with iron-deficiency anemia. Risk Factors You may have an increased risk for iron-deficiency anemia because of your age, ... or sex. Age You may be at increased risk for iron deficiency at certain ages: Infants between ...

Oral aversion to dietary sugar, ethanol and glycerol correlates with alterations in specific hepatic metabolites in a mouse model of human citrin deficiency.

Science.gov (United States)

Saheki, Takeyori; Inoue, Kanako; Ono, Hiromi; Fujimoto, Yuki; Furuie, Sumie; Yamamura, Ken-Ichi; Kuroda, Eishi; Ushikai, Miharu; Asakawa, Akihiro; Inui, Akio; Eto, Kazuhiro; Kadowaki, Takashi; Moriyama, Mitsuaki; Sinasac, David S; Yamamoto, Takashi; Furukawa, Tatsuhiko; Kobayashi, Keiko

2017-04-01

Mice carrying simultaneous homozygous mutations in the genes encoding citrin, the mitochondrial aspartate-glutamate carrier 2 (AGC2) protein, and mitochondrial glycerol-3-phosphate dehydrogenase (mGPD), are a phenotypically representative model of human citrin (a.k.a., AGC2) deficiency. In this study, we investigated the voluntary oral intake and preference for sucrose, glycerol or ethanol solutions by wild-type, citrin (Ctrn)-knockout (KO), mGPD-KO, and Ctrn/mGPD double-KO mice; all substances that are known or suspected precipitating factors in the pathogenesis of human citrin deficiency. The double-KO mice showed clear suppressed intake of sucrose, consuming less with progressively higher concentrations compared to the other mice. Similar observations were made when glycerol or ethanol were given. The preference of Ctrn-KO and mGPD-KO mice varied with the different treatments; essentially no differences were observed for sucrose, while an intermediate intake or similar to that of the double-KO mice was observed for glycerol and ethanol. We next examined the hepatic glycerol 3-phosphate, citrate, citrulline, lysine, glutamate and adenine nucleotide levels following forced enteral administration of these solutions. A strong correlation between the simultaneous increased hepatic glycerol 3-phosphate and decreased ATP or total adenine nucleotide content and observed aversion of the mice during evaluation of their voluntary preferences was found. Overall, our results suggest that the aversion observed in the double-KO mice to these solutions is initiated and/or mediated by hepatic metabolic perturbations, resulting in a behavioral response to increased hepatic cytosolic NADH and a decreased cellular adenine nucleotide pool. These findings may underlie the dietary predilections observed in human citrin deficient patients. Copyright © 2017 Elsevier Inc. All rights reserved.

Colossal positive magnetoresistance in surface-passivated oxygen-deficient strontium titanite

KAUST Repository

David, Adrian

2015-05-15

Modulation of resistance by an external magnetic field, i.e. magnetoresistance effect, has been a long-lived theme of research due to both fundamental science and device applications. Here we report colossal positive magnetoresistance (CPMR) (>30,000% at a temperature of 2 K and a magnetic field of 9 T) discovered in degenerate semiconducting strontium titanite (SrTiO3) single crystals capped with ultrathin SrTiO3/LaAlO3 bilayers. The low-pressure high-temperature homoepitaxial growth of several unit cells of SrTiO3 introduces oxygen vacancies and high-mobility carriers in the bulk SrTiO3, and the three-unit-cell LaAlO3 capping layer passivates the surface and improves carrier mobility by suppressing surface-defect-related scattering. The coexistence of multiple types of carriers and inhomogeneous transport lead to the emergence of CPMR. This unit-cell-level surface engineering approach is promising to be generalized to others oxides, and to realize devices with high-mobility carriers and interesting magnetoelectronic properties.

Iron-Deficiency Anemia

Medline Plus

Full Text Available ... Topics News & Resources Intramural Research Home / < Back To Health Topics / Iron-Deficiency Anemia Iron-Deficiency Anemia Also known as Leer ... and symptoms as well as complications from iron-deficiency anemia. Research for Your Health The NHLBI is part of the U.S. Department ...

Effect of consuming zinc-fortified bread on serum zinc and iron status of zinc-deficient women: A double blind, randomized clinical trial

Directory of Open Access Journals (Sweden)

Akbar Badii

2012-01-01

Full Text Available After iron deficiency, zinc deficiency is the major micronutrient deficiency in developing countries, and staple food fortification is an effective strategy to prevent and improve it among at-risk-populations. No action has been taken to reduce zinc deficiency via flour fortification so far in Iran, and little is known about the influence of zinc fortification of flour on serum zinc and the iron status, and also about the optimum and effective amount of zinc compound that is used in food fortification. The objective of this study is to evaluate the influence of consuming zinc-fortified breads on the zinc and iron status in the blood serum. In this study, three types of bread were prepared from non-fortified and fortified flours, with 50 and 100 ppm elemental zinc in the form of sulfate. Eighty zinc-deficient women aged 19 to 49 years were randomly assigned to three groups; The volunteers received, daily, (1 a non-fortified bread, (2 a high-zinc bread, and (3 a low-zinc bread for one month. Serum zinc and iron were measured by Atomic Absorption before and after the study. Results showed a significant increase in serum zinc and iron levels in all groups (p 0.05. Absorption of zinc and iron in the group that consumed high-zinc bread was significantly greater than that in the group that received low-zinc bread (p < 0.01. It was concluded that fortification of flour with 50-100 ppm zinc was an effective way to achieve adequate zinc intake and absorption in zinc-deficient people. It also appeared that consuming zinc-fortified bread improved iron absorption.

Aberrant Muscle Antigen Exposure in Mice Is Sufficient to Cause Myositis in a Treg Cell–Deficient Milieu

Science.gov (United States)

Young, Nicholas A; Sharma, Rahul; Friedman, Alexandra K; Kaffenberger, Benjamin H; Bolon, Brad; Jarjour, Wael N

2013-01-01

Objective Myositis is associated with muscle-targeted inflammation and is observed in some Treg cell–deficient mouse models. Because an autoimmune pathogenesis has been strongly implicated, the aim of this study was to investigate the hypothesis that abnormal exposure to muscle antigens, as observed in muscle injury, can induce autoimmune-mediated myositis in susceptible hosts. Methods FoxP3 mutant (scurfy) mice were mated to synaptotagmin VII (Syt VII) mutant mice, which resulted in a new mouse strain that combines impaired membrane resealing with Treg cell deficiency. Lymphocyte preparations from double-mutant mice were adoptively transferred intraperitoneally, with or without purified Treg cells, into recombination-activating gene 1 (RAG-1)–null recipients. Lymph node cells from mice with the FoxP3 mutation were transferred into RAG-1–null mice either 1) intraperitoneally in conjunction with muscle homogenate or purified myosin protein or 2) intramuscularly with or without cotransfer of purified Treg cells. Results FoxP3-deficient mouse lymph node cells transferred in conjunction with myosin protein or muscle homogenate induced robust skeletal muscle inflammation. The infiltrates consisted predominantly of CD4+ and CD8+ T cells, a limited number of macrophages, and no B cells. Significant inflammation was also seen in similar experiments using lymph node cells from FoxP3/Syt VII double-mutant mice but was absent in experiments using adoptive transfer of FoxP3 mutant mouse cells alone. The cotransfer of Treg cells completely suppressed myositis. Conclusion These data, derived from a new, reproducible model, demonstrate the critical roles of Treg cell deficiency and aberrant muscle antigen exposure in the priming of autoreactive cells to induce myositis. This mouse system has multifaceted potential for examining the interplay in vivo between tissue injury and autoimmunity. PMID:24022275

Effect of Cation Ordering on the Performance and Chemical Stability of Layered Double Perovskite Cathodes

Directory of Open Access Journals (Sweden)

Carlos Bernuy-Lopez

2018-01-01

Full Text Available The effect of A-site cation ordering on the cathode performance and chemical stability of A-site cation ordered LaBaCo2O5+δ and disordered La0.5Ba0.5CoO3−δ materials are reported. Symmetric half-cells with a proton-conducting BaZr0.9Y0.1O3−δ electrolyte were prepared by ceramic processing, and good chemical compatibility of the materials was demonstrated. Both A-site ordered LaBaCo2O5+δ and A-site disordered La0.5Ba0.5CoO3−δ yield excellent cathode performance with Area Specific Resistances as low as 7.4 and 11.5 Ω·cm2 at 400 °C and 0.16 and 0.32 Ω·cm2 at 600 °C in 3% humidified synthetic air respectively. The oxygen vacancy concentration, electrical conductivity, basicity of cations and crystal structure were evaluated to rationalize the electrochemical performance of the two materials. The combination of high-basicity elements and high electrical conductivity as well as sufficient oxygen vacancy concentration explains the excellent performance of both LaBaCo2O5+δ and La0.5Ba0.5CoO3−δ materials at high temperatures. At lower temperatures, oxygen-deficiency in both materials is greatly reduced, leading to decreased performance despite the high basicity and electrical conductivity. A-site cation ordering leads to a higher oxygen vacancy concentration, which explains the better performance of LaBaCo2O5+δ. Finally, the more pronounced oxygen deficiency of the cation ordered polymorph and the lower chemical stability at reducing conditions were confirmed by coulometric titration.

Determining the Source of Water Vapor in a Cerium Oxide Electrochemical Oxygen Separator to Achieve Aviator Grade Oxygen

Science.gov (United States)

Graf, John; Taylor, Dale; Martinez, James

2014-01-01

]. Combined with a mechanical compressor, a Solid Electrolyte Oxygen Separator (SEOS) should be capable of producing ABO grade oxygen at pressures >2400 psia, on the space station. Feasibility tests using a SEOS integrated with a mechanical compressor identified an unexpected contaminant in the oxygen: water vapour was found in the oxygen product, sometimes at concentrations higher than 40 ppm (the ABO limit for water vapour is 7 ppm). If solid electrolyte membranes are really "infinitely selective" to oxygen as they are reported to be, where did the water come from? If water is getting into the oxygen, what other contaminants might get into the oxygen? Microscopic analyses of wafers, welds, and oxygen delivery tubes were performed in an attempt to find the source of the water vapour contamination. Hot and cold pressure decay tests were performed. Measurements of water vapour as a function of O2 delivery rate, O2 delivery pressure, and process air humidity levels were the most instructive in finding the source of water contamination (Fig 3). Water contamination was directly affected by oxygen delivery rate (doubling the oxygen production rate cut the water level in half). Water was affected by process air humidity levels and delivery pressure in a way that indicates the water was diffusing into the oxygen delivery system.

Diagnostic examination of the urethra in the female and double-balloon urethrography as a diagnostic method

International Nuclear Information System (INIS)

Madeja, C.; Mutze, S.; Poetzschke, B.; Tunn, R.; Heinrich, G.; Hamm, B.

1997-01-01

The double-balloon urethrography can be recommended as an efficient diagnostic method for examination of the urethra in the female patient. Because of its improved controllability, retrograde application of the contrast agent is superior to other techniques. Complications can be avoided by maintaining constant pressure during contrast agent application. The few commercially available double-balloon instruments suffer from a number of deficiencies which are the reason for this technique having met with low acceptance, thus being only rarely applied. In addition, application of the instrument is not easy. Nevertheless, this diagnostic technique would deserve much more frequent application. (orig.) [de

Enhanced Reactive Oxygen Species Production, Acidic Cytosolic pH and Upregulated Na+/H+ Exchanger (NHE) in Dicer Deficient CD4+ T Cells.

Science.gov (United States)

Singh, Yogesh; Zhou, Yuetao; Zhang, Shaqiu; Abdelazeem, Khalid N M; Elvira, Bernat; Salker, Madhuri S; Lang, Florian

2017-01-01

MicroRNAs (miRNAs) negatively regulate gene expression at a post-transcriptional level. Dicer, a cytoplasmic RNase III enzyme, is required for the maturation of miRNAs from precursor miRNAs. Dicer, therefore, is a critical enzyme involved in the biogenesis and processing of miRNAs. Several biological processes are controlled by miRNAs, including the regulation of T cell development and function. T cells generate reactive oxygen species (ROS) with parallel H+ extrusion accomplished by the Na+/H+-exchanger 1 (NHE1). The present study explored whether ROS production, as well as NHE1 expression and function are sensitive to the lack of Dicer (miRNAs deficient) and could be modified by individual miRNAs. CD4+ T cells were isolated from CD4 specific Dicer deficient (DicerΔ/Δ) mice and the respective control mice (Dicerfl/fl). Transcript and protein levels were quantified with RT-PCR and Western blotting, respectively. For determination of intracellular pH (pHi) cells were incubated with the pH sensitive dye bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF) and Na+/H+ exchanger (NHE) activity was calculated from re-alkalinization after an ammonium pulse. Changes in cell volume were measured using the forward scatter in flow cytometry, and ROS production utilizing 2',7' -dichlorofluorescin diacetate (DCFDA) fluorescence. Transfection of miRNA-control and mimics in T cells was performed using DharmaFECT3 reagent. ROS production, cytosolic H+ concentration, NHE1 transcript and protein levels, NHE activity, and cell volume were all significantly higher in CD4+ T cells from DicerΔ/Δ mice than in CD4+ T cells from Dicerfl/fl mice. Furthermore, individual miR-200b and miR-15b modify pHi and NHE activity in Dicerfl/fl and DicerΔ/Δ CD4+ T cells, respectively. Lack of Dicer leads to oxidative stress, cytosolic acidification, upregulated NHE1 expression and activity as well as swelling of CD4+ T cells, functions all reversed by miR-15b or miR-200b. © 2017 The Author

Structural changes of polytetrafluoroethylene during irradiation in oxygen

International Nuclear Information System (INIS)

Liu, Shuling; Fu, Congli; Gu, Aiqun; Yu, Zili

2015-01-01

To study the effect of irradiation on PTFE structure and prepare modified PTFE micropowder, PTFE was irradiated with dose up to 4 MGy in oxygen at room temperature. The structures of both irradiated and unirradiated PTFE samples were comparatively characterized by IR, XPS, Raman spectra and XRD measurement. The results showed that new groups of acyl fluoride (COF), carboxylic acid (COOH) and trifluoromethyl (CF 3 ) were formed under heavy radiation exposure in oxygen. In addition, the expansion of crystallite size or crystal lattice was first reported for the irradiated PTFE. The formation of new chemical groups and the expansion of crystallite size were elucidated by structural changes occurring in irradiation. - Highlights: • The structural change of PTFE irradiated in O 2 is different from that in vacuum. • The double bond is not found in PTFE after irradiation in oxygen. • The new groups like COF, COOH and CF 3 are formed in PTFE after irradiation. • The expansion of crystallite size is observed in the irradiated PTFE

Prenatal iron deficiency causes sex-dependent mitochondrial dysfunction and oxidative stress in fetal rat kidneys and liver.

Science.gov (United States)

Woodman, Andrew G; Mah, Richard; Keddie, Danae; Noble, Ronan M N; Panahi, Sareh; Gragasin, Ferrante S; Lemieux, Hélène; Bourque, Stephane L

2018-06-01

Prenatal iron deficiency alters fetal developmental trajectories, which results in persistent changes in organ function. Here, we studied the effects of prenatal iron deficiency on fetal kidney and liver mitochondrial function. Pregnant Sprague-Dawley rats were fed partially or fully iron-restricted diets to induce a state of moderate or severe iron deficiency alongside iron-replete control rats. We assessed mitochondrial function via high-resolution respirometry and reactive oxygen species generation via fluorescence microscopy on gestational d 21. Hemoglobin levels were reduced in dams in the moderate (-31%) and severe groups (-54%) compared with controls, which was accompanied by 55% reductions in fetal hemoglobin levels in both moderate and severe groups versus controls. Male iron-deficient kidneys exhibited globally reduced mitochondrial content and respiration, as well as increased cytosolic superoxide and decreased NO. Female iron-deficient kidneys exhibited complex II down-regulation and increased mitochondrial oxidative stress. Male iron-deficient livers exhibited reduced complex IV respiration and increased cytosolic superoxide, whereas female liver tissues exhibited no alteration in oxidant levels or mitochondrial function. These findings indicate that prenatal iron deficiency causes changes in mitochondrial content and function as well as oxidant status in a sex- and organ-dependent manner, which may be an important mechanism that underlies the programming of cardiovascular disease.-Woodman, A. G., Mah, R., Keddie, D., Noble, R. M. N., Panahi, S., Gragasin, F. S., Lemieux, H., Bourque, S. L. Prenatal iron deficiency causes sex-dependent mitochondrial dysfunction and oxidative stress in fetal rat kidneys and liver.

Stoichiometric and Oxygen-Deficient VO2 as Versatile Hole Injection Electrode for Organic Semiconductors.

Science.gov (United States)

Fu, Keke; Wang, Rongbin; Katase, Takayoshi; Ohta, Hiromichi; Koch, Norbert; Duhm, Steffen

2018-03-28

Using photoemission spectroscopy, we show that the surface electronic structure of VO 2 is determined by the temperature-dependent metal-insulator phase transition and the density of oxygen vacancies, which depends on the temperature and ultrahigh vacuum (UHV) conditions. The atomically clean and stoichiometric VO 2 surface is insulating at room temperature and features an ultrahigh work function of up to 6.7 eV. Heating in UHV just above the phase transition temperature induces the expected metallic phase, which goes in hand with the formation of oxygen defects (up to 6% in this study), but a high work function >6 eV is maintained. To demonstrate the suitability of VO 2 as hole injection contact for organic semiconductors, we investigated the energy-level alignment with the prototypical organic hole transport material N, N'-di(1-naphthyl)- N, N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (NPB). Evidence for strong Fermi-level pinning and the associated energy-level bending in NPB is found, rendering an Ohmic contact for holes.

Experimental investigation of decay properties of neutron deficient $^{116-118}$Ba isotopes and test of $^{112-115}$Ba beam counts

CERN Multimedia

We propose to study decay of neutron deficient isotopes $^{116-118}$Ba using Double Sided Silicon Strip Detector (DSSSD). To study delayed-proton and $\\alpha$-decay branching ratios of $^{116-118}$Ba are of special interest because of their vicinity to the proton drip line. The nuclear life-times and properties of the proton unstable states of Cs isotopes, populated through decay of $^{116-118}$Ba isotopes will be measured. In addition to that we propose beam development of $^{112-115}$Ba to study exotic decay properties of these neutron deficient nuclei and to search for super-allowed $\\alpha$-decay in future.

Iodine deficiency disorders

Energy Technology Data Exchange (ETDEWEB)

Ali, S M [Pakistan Council for Science and Technology, Islamabad (Pakistan)

1994-12-31

Iodine deficiency (IDD) is one of the common problem in the diet. Iodine deficiency as prevalence of goiter in population occurs in the mountainous areas. There is consensus that 800 million people are at risk of IDD from living in iodine deficient area and 190 million from goiter. Very high prevalence of IDD in different parts of the world are striking. It has generally observed that in iodine-deficient areas about 50% are affected with goiter, 1-5% from cretinsim and 20% from impaired mental and/or mortor function. (A.B.).

Uterine dysfunction in biglycan and decorin deficient mice leads to dystocia during parturition.

Directory of Open Access Journals (Sweden)

Zhiping Wu

Full Text Available Cesarean birth rates are rising. Uterine dysfunction, the exact mechanism of which is unknown, is a common indication for Cesarean delivery. Biglycan and decorin are two small leucine-rich proteoglycans expressed in the extracellular matrix of reproductive tissues and muscle. Mice deficient in biglycan display a mild muscular dystrophy, and, along with mice deficient in decorin, are models of Ehlers-Danlos Syndrome, a connective tissue anomaly associated with uterine rupture. As a variant of Ehlers-Danlos Syndrome is caused by a genetic mutation resulting in abnormal biglycan and decorin secretion, we hypothesized that biglycan and decorin play a role in uterine function. Thus, we assessed wild-type, biglycan, decorin and double knockout pregnancies for timing of birth and uterine function. Uteri were harvested at embryonic days 12, 15 and 18. Nonpregnant uterine samples of the same genotypes were assessed for tissue failure rate and spontaneous and oxytocin-induced contractility. We discovered that biglycan/decorin mixed double-knockout dams displayed dystocia, were at increased risk of delayed labor onset, and showed increased tissue failure in a predominantly decorin-dependent manner. In vitro spontaneous uterine contractile amplitude and oxytocin-induced contractile force were decreased in all biglycan and decorin knockout genotypes compared to wild-type. Notably, we found no significant compensation between biglycan and decorin using quantitative real time PCR or immunohistochemistry. We conclude that the biglycan/decorin mixed double knockout mouse is a model of dystocia and delayed labor onset. Moreover, decorin is necessary for uterine function in a dose-dependent manner, while biglycan exhibits partial compensatory mechanisms in vivo. Thus, this model is poised for use as a model for testing novel targets for preventive or therapeutic manipulation of uterine dysfunction.

Uterine Dysfunction in Biglycan and Decorin Deficient Mice Leads to Dystocia during Parturition

Science.gov (United States)

Wu, Zhiping; Aron, Abraham W.; Macksoud, Elyse E.; Iozzo, Renato V.; Hai, Chi-Ming; Lechner, Beatrice E.

2012-01-01

Cesarean birth rates are rising. Uterine dysfunction, the exact mechanism of which is unknown, is a common indication for Cesarean delivery. Biglycan and decorin are two small leucine-rich proteoglycans expressed in the extracellular matrix of reproductive tissues and muscle. Mice deficient in biglycan display a mild muscular dystrophy, and, along with mice deficient in decorin, are models of Ehlers-Danlos Syndrome, a connective tissue anomaly associated with uterine rupture. As a variant of Ehlers-Danlos Syndrome is caused by a genetic mutation resulting in abnormal biglycan and decorin secretion, we hypothesized that biglycan and decorin play a role in uterine function. Thus, we assessed wild-type, biglycan, decorin and double knockout pregnancies for timing of birth and uterine function. Uteri were harvested at embryonic days 12, 15 and 18. Nonpregnant uterine samples of the same genotypes were assessed for tissue failure rate and spontaneous and oxytocin-induced contractility. We discovered that biglycan/decorin mixed double-knockout dams displayed dystocia, were at increased risk of delayed labor onset, and showed increased tissue failure in a predominantly decorin-dependent manner. In vitro spontaneous uterine contractile amplitude and oxytocin-induced contractile force were decreased in all biglycan and decorin knockout genotypes compared to wild-type. Notably, we found no significant compensation between biglycan and decorin using quantitative real time PCR or immunohistochemistry. We conclude that the biglycan/decorin mixed double knockout mouse is a model of dystocia and delayed labor onset. Moreover, decorin is necessary for uterine function in a dose-dependent manner, while biglycan exhibits partial compensatory mechanisms in vivo. Thus, this model is poised for use as a model for testing novel targets for preventive or therapeutic manipulation of uterine dysfunction. PMID:22253749

Low blood flow at onset of moderate-intensity exercise does not limit muscle oxygen uptake

DEFF Research Database (Denmark)

Nyberg, Michael Permin; Mortensen, Stefan P; Saltin, Bengt

2010-01-01

The effect of low blood flow at onset of moderate-intensity exercise on the rate of rise in muscle oxygen uptake was examined. Seven male subjects performed a 3.5-min one-legged knee-extensor exercise bout (24 +/- 1 W, mean +/- SD) without (Con) and with (double blockade; DB) arterial infusion...... of inhibitors of nitric oxide synthase (N(G)-monomethyl-l-arginine) and cyclooxygenase (indomethacin) to inhibit the synthesis of nitric oxide and prostanoids, respectively. Leg blood flow and leg oxygen delivery throughout exercise was 25-50% lower (P ... +/- 12 vs. 262 +/- 39 ml/min). The present data demonstrate that muscle blood flow and oxygen delivery can be markedly reduced without affecting muscle oxygen uptake in the initial phase of moderate-intensity exercise, suggesting that blood flow does not limit muscle oxygen uptake at the onset...

Psr is involved in regulation of glucan production, and double deficiency of BrpA and Psr is lethal in Streptococcus mutans.

Science.gov (United States)

Bitoun, Jacob P; Liao, Sumei; McKey, Briggs A; Yao, Xin; Fan, Yuwei; Abranches, Jacqueline; Beatty, Wandy L; Wen, Zezhang T

2013-03-01

Streptococcus mutans, the primary causative agent of dental caries, contains two paralogues of the LytR-CpsA-Psr family proteins encoded by brpA and psr, respectively. Previous studies have shown that BrpA plays an important role in cell envelope biogenesis/homeostasis and affects stress responses and biofilm formation by Strep. mutans, traits critical to cariogenicity of this bacterium. In this study, a Psr-deficient mutant, TW251, was constructed. Characterization of TW251 showed that deficiency of Psr did not have any major impact on growth rate. However, when subjected to acid killing at pH 2.8, the survival rate of TW251 was decreased dramatically compared with the parent strain UA159. In addition, TW251 also displayed major defects in biofilm formation, especially during growth with sucrose. When compared to UA159, the biofilms of TW251 were mainly planar and devoid of extracellular glucans. Real-time-PCR and Western blot analyses revealed that deficiency of Psr significantly decreased the expression of glucosyltransferase C, a protein known to play a major role in biofilm formation by Strep. mutans. Transmission electron microscopy analysis showed that deficiency of BrpA caused alterations in cell envelope and cell division, and the most significant defects were observed in TW314, a Psr-deficient and BrpA-down mutant. No such effects were observed with Psr mutant TW251 under similar conditions. These results suggest that while there are similarities in functions between BrpA and Psr, distinctive differences also exist between these two paralogues. Like Bacillus subtilis but different from Staphylococcus aureus, a functional BrpA or Psr is required for viability in Strep. mutans.

Iodine Deficiency

NARCIS (Netherlands)

Zimmermann, M.B.

2009-01-01

Iodine deficiency has multiple adverse effects in humans, termed iodine deficiency disorders, due to inadequate thyroid hormone production. Globally, it is estimated that 2 billion individuals have an insufficient iodine intake, and South Asia and sub-Saharan Africa are particularly affected.

UV and gamma-ray sensitivity of meiosis-deficient mutants in Podospora anserina

International Nuclear Information System (INIS)

Simonet, J.M.

1976-01-01

Two mutants, mei1 and mei2, were isolated by screening for deficiencies occurring in the meiotic process. The sensitivity of mei1 and mei2 mutant strains to UV irradiation showed a significant increase as compared with that of the wild-type stock, hwhereas the sensitivity to γ-rays remained unchanged. The double-mutant strains were no more sensitive than each single mutant. The data indicate that both mei1 and mei2 loci are probably involved in the same pathway of excision-repair of UV-induced lesions

Extra-large pore zeolite (ITQ-40) with the lowest framework density containing double four- and double three-rings

Science.gov (United States)

Díaz-Cabañas, M. J.; Jiang, J.; Afeworki, M.; Dorset, D. L.; Soled, S. L.; Strohmaier, K. G.

2010-01-01

The first zeolite structure (ITQ-40) that contains double four (D4) and double three (D3) member ring secondary building units has been synthesized by introducing Ge and NH4F and working in concentrated synthesis gels. It is the first time that D3-Rs have been observed in a zeolite structure. As was previously analyzed [Brunner GO, Meier, WM (1989) Nature 337:146–147], such a structure has a very low framework density (10.1 T/1,000 Å3). Indeed, ITQ-40 has the lowest framework density ever achieved in oxygen-containing zeolites. Furthermore, it contains large pore openings, i.e., 15-member rings parallel to the [001] hexagonal axis and 16-member ring channels perpendicular to this axis. The results presented here push ahead the possibilities of zeolites for uses in electronics, control delivery of drugs and chemicals, as well as for catalysis. PMID:20660773

Effect of Consuming Zinc-fortified Bread on Serum Zinc and Iron Status of Zinc-deficient Women: A Double Blind, Randomized Clinical Trial.

Science.gov (United States)

Badii, Akbar; Nekouei, Niloufar; Fazilati, Mohammad; Shahedi, Mohammad; Badiei, Sajad

2012-03-01

After iron deficiency, zinc deficiency is the major micronutrient deficiency in developing countries, and staple food fortification is an effective strategy to prevent and improve it among at-risk-populations. No action has been taken to reduce zinc deficiency via flour fortification so far in Iran, and little is known about the influence of zinc fortification of flour on serum zinc and the iron status, and also about the optimum and effective amount of zinc compound that is used in food fortification. The objective of this study is to evaluate the influence of consuming zinc-fortified breads on the zinc and iron status in the blood serum. In this study, three types of bread were prepared from non-fortified and fortified flours, with 50 and 100 ppm elemental zinc in the form of sulfate. Eighty zinc-deficient women aged 19 to 49 years were randomly assigned to three groups; The volunteers received, daily, (1) a non-fortified bread, (2) a high-zinc bread, and (3) a low-zinc bread for one month. Serum zinc and iron were measured by Atomic Absorption before and after the study. Results showed a significant increase in serum zinc and iron levels in all groups (p 0.05). Absorption of zinc and iron in the group that consumed high-zinc bread was significantly greater than that in the group that received low-zinc bread (p bread improved iron absorption.

Radiation-induced mitotic catastrophe in PARG-deficient cells

Energy Technology Data Exchange (ETDEWEB)

Ame, J.Ch.; Fouquerel, E.; Dantzer, F.; De Murcia, G.; Schreiber, V. [IREBS-FRE3211 du CNRS, Universite de Strasbourg, ESBS, Bd Sebastien Brant, BP 10413, 67412 Illkirch Cedex (France); Gauthier, L.R.; Boussin, F.D. [Laboratoire de Radiopathologie/INSERM U967, CEA-DSV-IRCM, 92265 Fontenay aux Roses, Cedex 6 (France); Biard, D. [CEA-DSV-IRCM/INSERM U935, Institut A. Lwoff-CNRS, BP 8, 94801 Villejuif cedex (France)

2009-07-01

Poly(ADP-ribosyl)ation is a post-translational modification of proteins involved in the regulation of chromatin structure, DNA metabolism, cell division and cell death. Through the hydrolysis of poly(ADP-ribose) (PAR), Poly(ADP-ribose) glyco-hydrolase (PARG) has a crucial role in the control of life-and-death balance following DNA insult. Comprehension of PARG function has been hindered by the existence of many PARG isoforms encoded by a single gene and displaying various subcellular localizations. To gain insight into the function of PARG in response to irradiation, we constitutively and stably knocked down expression of PARG isoforms in HeLa cells. PARG depletion leading to PAR accumulation was not deleterious to undamaged cells and was in fact rather beneficial, because it protected cells from spontaneous single-strand breaks and telomeric abnormalities. By contrast, PARG-deficient cells showed increased radiosensitivity, caused by defects in the repair of single- and double-strand breaks and in mitotic spindle checkpoint, leading to alteration of progression of mitosis. Irradiated PARG-deficient cells displayed centrosome amplification leading to mitotic supernumerary spindle poles, and accumulated aberrant mitotic figures, which induced either polyploidy or cell death by mitotic catastrophe. Our results suggest that PARG could be a novel potential therapeutic target for radiotherapy. (authors)

Direct observation of the order-disorder transformation of the oxygen sublattice of Ba2YCu3O7-δ

International Nuclear Information System (INIS)

Tendeloo, G. van; Amelinckx, S.

1987-01-01

Detailed evidence for the order-disorder transformation in the superconducting compound Ba 2 YCu 3 O 7-δ is presented by studying heating experiments in the vacuum of the electron microscope using heat pulses from the electron beam. The reappearance of the twin interface and of the related orthorhombic spot splitting in heat-pulse produced tetragonal phase demonstrates clearly the high mobility of oxygen in this material. A new model for the superstructure is proposed related to a deficiency in oxygen

Carnitine Deficiency and Pregnancy

Directory of Open Access Journals (Sweden)

Anouk de Bruyn

2015-01-01

Full Text Available We present two cases of carnitine deficiency in pregnancy. In our first case, systematic screening revealed L-carnitine deficiency in the first born of an asymptomatic mother. In the course of her second pregnancy, maternal carnitine levels showed a deficiency as well. In a second case, a mother known with carnitine deficiency under supplementation was followed throughout her pregnancy. Both pregnancies had an uneventful outcome. Because carnitine deficiency can have serious complications, supplementation with carnitine is advised. This supplementation should be continued throughout pregnancy according to plasma concentrations.

A close correlation between induced ferromagnetism and oxygen deficiency in Fe doped In2O3

International Nuclear Information System (INIS)

Singhal, R.K.; Samariya, A.; Kumar, Sudhish; Sharma, S.C.; Xing, Y.T.; Deshpande, U.P.; Shripathi, T.; Saitovitch, E.

2010-01-01

We report on the reversible manipulation of room temperature ferromagnetism in Fe (5%) doped In 2 O 3 polycrystalline magnetic semiconductor. The X-ray diffraction and photoemission measurements confirm that the Fe ions are well incorporated into the lattice, substituting the In 3+ ions. The magnetization measurements show that the host In 2 O 3 has a diamagnetic ground state, while it shows weak ferromagnetism at 300 K upon Fe doping. The as-prepared sample was then sequentially annealed in hydrogen, air, vacuum and finally in air. The ferromagnetic signal shoots up by hydrogenation as well as vacuum annealing and bounces back upon re-annealing the samples in air. The sequence of ferromagnetism shows a close inter-relationship with the behavior of oxygen vacancies (V o ). The Fe ions tend to a transform from 3+ to 2+ state during the giant ferromagnetic induction, as revealed by photoemission spectroscopy. A careful characterization of the structure, purity, magnetic, and transport properties confirms that the ferromagnetism is due to neither impurities nor clusters but directly related to the oxygen vacancies. The ferromagnetism can be reversibly controlled by these vacancies while a parallel variation of carrier concentration, as revealed by resistance measurements, appears to be a side effect of the oxygen vacancy variation.

Radio-sensitization of WRN helicase deficient cancer cells by targeting homologous recombination pathway

International Nuclear Information System (INIS)

Gupta, Pooja; Saha, Bhaskar; Patro, Birija Sankar; Chattopadhyay, Subrata

2016-01-01

Ionizing radiation (IR) induced DNA double-strand breaks (DSBs) are primarily repaired by non-homologous end joining (NHEJ). However, it is well established that a subset DSBs which are accumulated in IR-induced G2 phase are dependent on homologous recombination (HR). DNA repair deficient tumor cells have been shown to accumulate high levels of DNA damage. Consequently, these cells become hyperdependent on DNA damage response pathways, including the CHK1-kinase-mediated HR-repair. These observations suggest that DNA repair deficient tumors should exhibit increased radio-sensitivity under HR inhibition. Genetic defects leading to functional loss of werner (WRN) protein is associated with genomic instability and increased cancer incidence. WRN function is known to be abrogated in several human cancer cells due to hypermethylation of CpGisland-promoter and transcriptional silencing of WRN gene. In the current investigation, using isogenic pairs of cell lines differing only in the WRN function, we showed that WRN-deficient cell lines were hyper-radiosensitive to CHK1 pharmacologic inhibition. Here, we found that unrepaired DSB was drastically increased in WRN-deficient cells vis-à-vis WRN-proficient cells in response to IR and CHK1 inhibitor (CHK1i). Our results revealed a marginal role of NHEJ pathway accountable for the radio-sensitivity of WRN-deficient cells. Interestingly, silencing CTIP, a HR protein required for RAD51 loading, significantly abrogated the CHK1i-mediated radiosensitivity in WRN-deficient cells. Silencing of WRN or CTIP individually led to no significant difference in the extent of DNA end resection, as required during HR pathway. Imperatively, our results revealed that WRN and CTIP together play a complementary role in executing DNA end resection during HR-mediated repair of IR induced DSBs. Altogether, our data indicated that inhibition of IR-induced HR pathway at RAD51 loading, but not at DSB end resection, make the WRN-deficient cancer cells

High intensity aerobic interval training improves peak oxygen consumption in patients with metabolic syndrome: CAT

Directory of Open Access Journals (Sweden)

Alexis Espinoza Salinas

2014-06-01

Full Text Available Introduction A number of cardiovascular risk factors characterizes the metabolic syndrome: insulin resistance (IR, low HDL cholesterol and high triglycerides. The aforementioned risk factors lead to elevated levels of abdominal adipose tissue, resulting in oxygen consumption deficiency. Purpose To verify the validity and applicability of using high intensity interval training (HIIT in subjects with metabolic syndrome and to answer the following question: Can HIIT improve peak oxygen consumption? Method The systematic review "Effects of aerobic interval training on exercise capacity and metabolic risk factors in individuals with cardiometabolic disorders" was analyzed. Results Data suggests high intensity aerobic interval training increases peak oxygen consumption by a standardized mean difference of 3.60 mL/kg-1/min-1 (95% confidence interval, 0.28-4.91. Conclusion In spite of the methodological shortcomings of the primary studies included in the systematic review, we reasonably conclude that implementation of high intensity aerobic interval training in subjects with metabolic syndrome, leads to increases in peak oxygen consumption.

Hyperbaric Oxygen Environment Can Enhance Brain Activity and Multitasking Performance.

Science.gov (United States)

Vadas, Dor; Kalichman, Leonid; Hadanny, Amir; Efrati, Shai

2017-01-01

Background: The Brain uses 20% of the total oxygen supply consumed by the entire body. Even though, multitasking), the oxygen supply is shifted from one brain region to another, via blood perfusion modulation. The aim of the present study was to evaluate whether a hyperbaric oxygen (HBO) environment, with increased oxygen supply to the brain, will enhance the performance of complex and/or multiple activities. Methods: A prospective, double-blind randomized control, crossover trial including 22 healthy volunteers. Participants were asked to perform a cognitive task, a motor task and a simultaneous cognitive-motor task (multitasking). Participants were randomized to perform the tasks in two environments: (a) normobaric air (1 ATA 21% oxygen) (b) HBO (2 ATA 100% oxygen). Two weeks later participants were crossed to the alternative environment. Blinding of the normobaric environment was achieved in the same chamber with masks on while hyperbaric sensation was simulated by increasing pressure in the first minute and gradually decreasing to normobaric environment prior to tasks performance. Results: Compared to the performance at normobaric conditions, both cognitive and motor single tasks scores were significantly enhanced by HBO environment ( p Multitasking performance was also significantly enhanced in HBO environment ( p = 0.006 for the cognitive part and p = 0.02 for the motor part). Conclusions: The improvement in performance of both single and multi-tasking while in an HBO environment supports the hypothesis which according to, oxygen is indeed a rate limiting factor for brain activity. Hyperbaric oxygenation can serve as an environment for brain performance. Further studies are needed to evaluate the optimal oxygen levels for maximal brain performance.

Vitamin D3 Loading Is Superior to Conventional Supplementation After Weight Loss Surgery in Vitamin D-Deficient Morbidly Obese Patients: a Double-Blind Randomized Placebo-Controlled Trial.

Science.gov (United States)

Luger, Maria; Kruschitz, Renate; Kienbacher, Christian; Traussnigg, Stefan; Langer, Felix B; Prager, Gerhard; Schindler, Karin; Kallay, Enikö; Hoppichler, Friedrich; Trauner, Michael; Krebs, Michael; Marculescu, Rodrig; Ludvik, Bernhard

2017-05-01

Bariatric patients often suffer from vitamin D deficiency (VDD), and both, morbid obesity and VDD, are related to non-alcoholic fatty liver disease. However, limited data are available regarding best strategies for treating VDD, particularly, in bariatric patients undergoing omega-loop gastric bypass (OLGB). Therefore, we examined the efficacy and safety of a forced vitamin D dosing regimen and intervention effects in liver fibrotic patients. In this double-blind, randomized, placebo-controlled trial, 50 vitamin D-deficient patients undergoing OLGB were randomly assigned to receive, in the first month postoperatively, oral vitamin D 3 (≤3 doses of 100,000 IU; intervention group) or placebo as loading dose (control group) with subsequent maintenance dose (3420 IU/day) in both groups until 6-month visit. Compared with control group, higher increase of 25(OH)D (67.9 (21.1) vs. 55.7 nmol/L (21.1); p = 0.049) with lower prevalence of secondary hyperparathyroidism (10 vs. 24 %; p = 0.045) was observed in intervention group. No (serious) adverse events related to study medication were found. The loading dose regimen was more effective in increasing 25(OH)D in patients with significant liver fibrosis while this was not the case for conventional supplementation (placebo with maintenance dose) (71.5 (20.5) vs. 22.5 nmol/L (13.8); p = 0.022; n = 14). Our findings indicate that a high vitamin D 3 loading dose, in the first month postoperatively, with subsequent maintenance dose is effective and safe in achieving higher vitamin D concentrations in OLGB patients. Unexpectedly, it is more effective in patients with significant liver fibrosis which is of potentially high clinical relevance and requires further investigation.

Effect of high hydrostatic pressure on small oxygen-related clusters in silicon: LVM studies

International Nuclear Information System (INIS)

Murin, L.I.; Lindstroem, J.L.; Misiuk, A.

2003-01-01

Local vibrational mode (LVM) spectroscopy is used to explore the effect of high hydrostatic pressure (HP) on the formation of small oxygen-related clusters (dimers, trimers, thermal donors, and C-O complexes) at 450 deg. C and 650 deg. C in Cz-Si crystals with different impurity content and prehistory. It is found, in agreement with previous studies, that HP enhances the oxygen clustering in Cz-Si at elevated temperatures. The effect of HP is related mainly to enhancement in the diffusivity of single oxygen atoms and small oxygen aggregates. HP does not noticeably increase the binding energies of the most simple oxygen related complexes like O 2i , C s O ni . The biggest HP effect on the thermal double donor (TDDs) generation is revealed in hydrogenated samples. Heat-treatment of such samples at 450 deg. C under HP results in extremely high TDD introduction rates as well as in a strong increase in the concentration of the first TDD species

STS-84 oxygen generator for Mir on display at SPACEHAB

Science.gov (United States)

1997-01-01

Representatives of RSC Energia in Russia and other onlookers in the SPACEHAB Payload Processing Facility examine an oxygen generator which the Space Shuttle Atlantis will carry to the Russian Mir Space Station on Mission STS-84. Sergei Romanov, second from right in the white shirt, is the spokesperson for generator manufacturer RSC Energia. The nearly 300-pound generator will be strapped down on the inside surface of a SPACEHAB Double Module for the trip to Mir. It will replace one of two Mir units that have been malfunctioning recently. The generator functions by electrolysis, which separates water into its oxygen and hydrogen components. The hydrogen is vented and the oxygen is used for breathing by the Mir crew. The generator is 4.2 feet in length and 1.4 feet in diameter. STS-84, which is planned to include a Mir crew exchange of astronaut C. Michael Foale for Jerry M. Linenger, is targeted for a May 15 liftoff. It will be the sixth Shuttle-Mir docking.

MHC class II expression through a hitherto unknown pathway supports T helper cell-dependent immune responses: implications for MHC class II deficiency.

Science.gov (United States)

Buch, Thorsten; Polic, Bojan; Clausen, Björn E; Weiss, Susanne; Akilli-Ozturk, Ozlem; Chang, Cheong-Hee; Flavell, Richard; Schulz, Ansgar; Jonjic, Stipan; Waisman, Ari; Förster, Irmgard

2006-02-15

MHC class II (MHCII) deficiency or bare lymphocyte syndrome (BLS) is a severe immunodeficiency characterized by deficient T helper (Th)-cell-dependent immunity. The disease is caused by defects of the MHCII promoter complex resulting in low or absent MHCII expression. We demonstrate in a murine model of MHCII deficiency (RFX5- or CIITA-deficient mice) that residual MHCII expression by professional antigen-presenting cells (APCs) is sufficient to support activation of adoptively transferred Th cells. Furthermore, upon transplantation of WT thymic epithelium, we observed development of endogenous Th cells with restoration of Th-cell-dependent antibody responses and immunity to cytomegalovirus infection, thus opening the possibility of an alternative treatment regimen for BLS. Residual MHCII expression was further induced by the presence of Th cells and also other stimuli. Analysis of CIITA/RFX5 double-deficient animals revealed that this inducible MHCII expression is genetically independent of the known promoter complex and thus constitutes an alternative MHCII expression pathway. In these experiments, we also detected a novel repressive function of the RFX complex in the absence of CIITA.

ATM protein is deficient in over 40% of lung adenocarcinomas.

Science.gov (United States)

Villaruz, Liza C; Jones, Helen; Dacic, Sanja; Abberbock, Shira; Kurland, Brenda F; Stabile, Laura P; Siegfried, Jill M; Conrads, Thomas P; Smith, Neil R; O'Connor, Mark J; Pierce, Andrew J; Bakkenist, Christopher J

2016-09-06

Lung cancer is the leading cause of cancer-related mortality in the USA and worldwide, and of the estimated 1.2 million new cases of lung cancer diagnosed every year, over 30% are lung adenocarcinomas. The backbone of 1st-line systemic therapy in the metastatic setting, in the absence of an actionable oncogenic driver, is platinum-based chemotherapy. ATM and ATR are DNA damage signaling kinases activated at DNA double-strand breaks (DSBs) and stalled and collapsed replication forks, respectively. ATM protein is lost in a number of cancer cell lines and ATR kinase inhibitors synergize with cisplatin to resolve xenograft models of ATM-deficient lung cancer. We therefore sought to determine the frequency of ATM loss in a tissue microarray (TMA) of lung adenocarcinoma. Here we report the validation of a commercial antibody (ab32420) for the identification of ATM by immunohistochemistry and estimate that 61 of 147 (41%, 95% CI 34%-50%) cases of lung adenocarcinoma are negative for ATM protein expression. As a positive control for ATM staining, nuclear ATM protein was identified in stroma and immune infiltrate in all evaluable cases. ATM loss in lung adenocarcinoma was not associated with overall survival. However, our preclinical findings in ATM-deficient cell lines suggest that ATM could be a predictive biomarker for synergy of an ATR kinase inhibitor with standard-of-care cisplatin. This could improve clinical outcome in 100,000's of patients with ATM-deficient lung adenocarcinoma every year.

Hyperbaric Oxygen Environment Can Enhance Brain Activity and Multitasking Performance

Directory of Open Access Journals (Sweden)

Dor Vadas

2017-09-01

Full Text Available Background: The Brain uses 20% of the total oxygen supply consumed by the entire body. Even though, <10% of the brain is active at any given time, it utilizes almost all the oxygen delivered. In order to perform complex tasks or more than one task (multitasking, the oxygen supply is shifted from one brain region to another, via blood perfusion modulation. The aim of the present study was to evaluate whether a hyperbaric oxygen (HBO environment, with increased oxygen supply to the brain, will enhance the performance of complex and/or multiple activities.Methods: A prospective, double-blind randomized control, crossover trial including 22 healthy volunteers. Participants were asked to perform a cognitive task, a motor task and a simultaneous cognitive-motor task (multitasking. Participants were randomized to perform the tasks in two environments: (a normobaric air (1 ATA 21% oxygen (b HBO (2 ATA 100% oxygen. Two weeks later participants were crossed to the alternative environment. Blinding of the normobaric environment was achieved in the same chamber with masks on while hyperbaric sensation was simulated by increasing pressure in the first minute and gradually decreasing to normobaric environment prior to tasks performance.Results: Compared to the performance at normobaric conditions, both cognitive and motor single tasks scores were significantly enhanced by HBO environment (p < 0.001 for both. Multitasking performance was also significantly enhanced in HBO environment (p = 0.006 for the cognitive part and p = 0.02 for the motor part.Conclusions: The improvement in performance of both single and multi-tasking while in an HBO environment supports the hypothesis which according to, oxygen is indeed a rate limiting factor for brain activity. Hyperbaric oxygenation can serve as an environment for brain performance. Further studies are needed to evaluate the optimal oxygen levels for maximal brain performance.

Modulation of the Singlet Oxygen Generation from the Double Strand DNA-SYBR Green I Complex Mediated by T-Melamine-T Mismatch for Visual Detection of Melamine.

Science.gov (United States)

Hu, Hao; Zhang, Jinyi; Ding, Yu; Zhang, Xinfeng; Xu, Kailai; Hou, Xiandeng; Wu, Peng

2017-05-02

Singlet oxygen ( 1 O 2 ), generated via photosensitization, has been proved to oxidize chromogenic substrates with neither H 2 O 2 oxidation nor enzyme (horseradish peroxidase, HRP) catalysis. Of the various methods for modulation of the 1 O 2 generation, DNA-controlled photosensitization received great attention. Therefore, integration of the formation/deformation DNA structures with DNA-controlled photosensitization will be extremely appealing in visual biosensor developments. Here, the stable melamine-thymine complex was explored in combination with DNA-controlled photosensitization for visual detection of melamine. A T-rich single stand DNA was utilized as the recognition unit. Upon the formation of the T-M-T complex, double stand DNA was formed, which was ready for the binding of SYBR Green I and activated the photosensitization. Subsequent oxidation of TMB allowed visual detection of melamine in dairy products, with spike-recoveries ranging from 94% to 106%.

Cytotoxicity of InP/ZnS quantum dots related to reactive oxygen species generation

Science.gov (United States)

Chibli, Hicham; Carlini, Lina; Park, Soonhyang; Dimitrijevic, Nada M.; Nadeau, Jay L.

2011-06-01

Indium phosphide (InP) quantum dots (QDs) have emerged as a presumably less hazardous alternative to cadmium-based particles, but their cytotoxicity has not been well examined. Although their constituent elements are of very low toxicity to cells in culture, they nonetheless exhibit phototoxicity related to generation of reactive oxygen species by excited electrons and/or holes interacting with water and molecular oxygen. Using spin-trap electron paramagnetic resonance (EPR) spectroscopy and reporter assays, we find a considerable amount of superoxide and a small amount of hydroxyl radical formed under visible illumination of biocompatible InP QDs with a single ZnS shell, comparable to what is seen with CdTe. A double thickness shell reduces the reactive oxygen species concentration approximately two-fold. Survival assays in five cell lines correspondingly indicate a distinct reduction in toxicity with the double-shell InP QDs. Toxicity varies significantly across cell lines according to the efficiency of uptake, being overall significantly less than what is seen with CdTe or CdSe/ZnS. This indicates that InP QDs are a useful alternative to cadmium-containing QDs, while remaining capable of electron-transfer processes that may be undesirable or which may be exploited for photosensitization applications.

Cytotoxicity of InP/ZnS quantum dots related to reactive oxygen species generation.

Energy Technology Data Exchange (ETDEWEB)

Chibli, H.; Carlini, L.; Park, S.; Dimitrijevic, N. M.; Nadeau, J. L. (Center for Nanoscale Materials); ( CSE); (McGill Univ.)

2011-01-01

Indium phosphide (InP) quantum dots (QDs) have emerged as a presumably less hazardous alternative to cadmium-based particles, but their cytotoxicity has not been well examined. Although their constituent elements are of very low toxicity to cells in culture, they nonetheless exhibit phototoxicity related to generation of reactive oxygen species by excited electrons and/or holes interacting with water and molecular oxygen. Using spin-trap electron paramagnetic resonance (EPR) spectroscopy and reporter assays, we find a considerable amount of superoxide and a small amount of hydroxyl radical formed under visible illumination of biocompatible InP QDs with a single ZnS shell, comparable to what is seen with CdTe. A double thickness shell reduces the reactive oxygen species concentration approximately two-fold. Survival assays in five cell lines correspondingly indicate a distinct reduction in toxicity with the double-shell InP QDs. Toxicity varies significantly across cell lines according to the efficiency of uptake, being overall significantly less than what is seen with CdTe or CdSe/ZnS. This indicates that InP QDs are a useful alternative to cadmium-containing QDs, while remaining capable of electron-transfer processes that may be undesirable or which may be exploited for photosensitization applications.

Enhanced thermoelectric property of oxygen deficient nickel doped SnO2 for high temperature application

Science.gov (United States)

Paulson, Anju; Sabeer, N. A. Muhammad; Pradyumnan, P. P.

2018-04-01

Motivated by the detailed investigation on the thermoelectric performance of oxide materials our work concentrated on the influence of acceptor dopants and defect density in the lattice plane for the enhancement of thermoelectric power. The series of Sn1‑x Nix O2 (0.01 ≤ x ≤ 0.05) compositions were prepared by solid state reaction mechanism and found that 3 atomic percentage Ni doped SnO2 can be considered as a good candidate due to its promising electrical and transport properties. Defect lattices were introduced in the sample and the deviation from oxygen stochiometry was ensured using photoluminescence measurement. High power factor was obtained for the 3 atomic percentage nickel doped SnO2 due to the effective number of charge carrier concentration and the depletion of oxygen rich layers. Defect centered and acceptor doped SnO2 lattice opens a new door for energy harvesting at higher temperatures.

A Comprehensive X-Ray Absorption Model for Atomic Oxygen

Science.gov (United States)

Gorczyca, T. W.; Bautista, M. A.; Hasoglu, M. F.; Garcia, J.; Gatuzz, E.; Kaastra, J. S.; Kallman, T. R.; Manson, S. T.; Mendoza, C.; Raassen, A. J. J.;

Iron-Deficiency Anemia (For Parents)

Science.gov (United States)

... Videos for Educators Search English Español Iron-Deficiency Anemia KidsHealth / For Parents / Iron-Deficiency Anemia What's in ... common nutritional deficiency in children. About Iron-Deficiency Anemia Every red blood cell in the body contains ...

Reactive Oxygen Species-Mediated Loss of Synaptic Akt1 Signaling Leads to Deficient Activity-Dependent Protein Translation Early in Alzheimer's Disease.

Science.gov (United States)

Ahmad, Faraz; Singh, Kunal; Das, Debajyoti; Gowaikar, Ruturaj; Shaw, Eisha; Ramachandran, Arathy; Rupanagudi, Khader Valli; Kommaddi, Reddy Peera; Bennett, David A; Ravindranath, Vijayalakshmi

2017-12-01

Synaptic deficits are known to underlie the cognitive dysfunction seen in Alzheimer's disease (AD). Generation of reactive oxygen species (ROS) by β-amyloid has also been implicated in AD pathogenesis. However, it is unclear whether ROS contributes to synaptic dysfunction seen in AD pathogenesis and, therefore, we examined whether altered redox signaling could contribute to synaptic deficits in AD. Activity dependent but not basal translation was impaired in synaptoneurosomes from 1-month old presymptomatic APP Swe /PS1ΔE9 (APP/PS1) mice, and this deficit was sustained till middle age (MA, 9-10 months). ROS generation leads to oxidative modification of Akt1 in the synapse and consequent reduction in Akt1-mechanistic target of rapamycin (mTOR) signaling, leading to deficiency in activity-dependent protein translation. Moreover, we found a similar loss of activity-dependent protein translation in synaptoneurosomes from postmortem AD brains. Loss of activity-dependent protein translation occurs presymptomatically early in the pathogenesis of AD. This is caused by ROS-mediated loss of pAkt1, leading to reduced synaptic Akt1-mTOR signaling and is rescued by overexpression of Akt1. ROS-mediated damage is restricted to the synaptosomes, indicating selectivity. We demonstrate that ROS-mediated oxidative modification of Akt1 contributes to synaptic dysfunction in AD, seen as loss of activity-dependent protein translation that is essential for synaptic plasticity and maintenance. Therapeutic strategies promoting Akt1-mTOR signaling at synapses may provide novel target(s) for disease-modifying therapy in AD. Antioxid. Redox Signal. 27, 1269-1280.

Iron deficiency and cognitive functions

Directory of Open Access Journals (Sweden)

Jáuregui-Lobera I

2014-11-01

Full Text Available Ignacio Jáuregui-Lobera Department of Nutrition and Bromatology, Pablo de Olavide University, Seville, Spain Abstract: Micronutrient deficiencies, especially those related to iodine and iron, are linked to different cognitive impairments, as well as to potential long-term behavioral changes. Among the cognitive impairments caused by iron deficiency, those referring to attention span, intelligence, and sensory perception functions are mainly cited, as well as those associated with emotions and behavior, often directly related to the presence of iron deficiency anemia. In addition, iron deficiency without anemia may cause cognitive disturbances. At present, the prevalence of iron deficiency and iron deficiency anemia is 2%–6% among European children. Given the importance of iron deficiency relative to proper cognitive development and the alterations that can persist through adulthood as a result of this deficiency, the objective of this study was to review the current state of knowledge about this health problem. The relevance of iron deficiency and iron deficiency anemia, the distinction between the cognitive consequences of iron deficiency and those affecting specifically cognitive development, and the debate about the utility of iron supplements are the most relevant and controversial topics. Despite there being methodological differences among studies, there is some evidence that iron supplementation improves cognitive functions. Nevertheless, this must be confirmed by means of adequate follow-up studies among different groups. Keywords: iron deficiency, anemia, cognitive functions, supplementation

Double hard scattering without double counting

Energy Technology Data Exchange (ETDEWEB)

Diehl, Markus [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Gaunt, Jonathan R. [VU Univ. Amsterdam (Netherlands). NIKHEF Theory Group; Schoenwald, Kay [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

2017-02-15

Double parton scattering in proton-proton collisions includes kinematic regions in which two partons inside a proton originate from the perturbative splitting of a single parton. This leads to a double counting problem between single and double hard scattering. We present a solution to this problem, which allows for the definition of double parton distributions as operator matrix elements in a proton, and which can be used at higher orders in perturbation theory. We show how the evaluation of double hard scattering in this framework can provide a rough estimate for the size of the higher-order contributions to single hard scattering that are affected by double counting. In a numeric study, we identify situations in which these higher-order contributions must be explicitly calculated and included if one wants to attain an accuracy at which double hard scattering becomes relevant, and other situations where such contributions may be neglected.

Double hard scattering without double counting

International Nuclear Information System (INIS)

Diehl, Markus; Gaunt, Jonathan R.

2017-02-01

Double parton scattering in proton-proton collisions includes kinematic regions in which two partons inside a proton originate from the perturbative splitting of a single parton. This leads to a double counting problem between single and double hard scattering. We present a solution to this problem, which allows for the definition of double parton distributions as operator matrix elements in a proton, and which can be used at higher orders in perturbation theory. We show how the evaluation of double hard scattering in this framework can provide a rough estimate for the size of the higher-order contributions to single hard scattering that are affected by double counting. In a numeric study, we identify situations in which these higher-order contributions must be explicitly calculated and included if one wants to attain an accuracy at which double hard scattering becomes relevant, and other situations where such contributions may be neglected.

Genotypic variations in photosynthetic and physiological adjustment to potassium deficiency in cotton (Gossypium hirsutum).

Science.gov (United States)

Wang, Ning; Hua, Hanbai; Eneji, A Egrinya; Li, Zhaohu; Duan, Liusheng; Tian, Xiaoli

2012-05-02

A hydroponic culture experiment was conducted to determine genotypic variation in photosynthetic rate and the associated physiological changes in response to potassium (K) deficiency in cotton (Gossypium hirsutum L.) seedlings with contrasting two cotton cultivars in K efficiency. The K-efficient Liaomian18 produced 66.7% more biomass than the K-inefficient NuCOTN99(B) under K deficiency, despite their similar biomass under K sufficiency. Compared with NuCOTN99(B), Liaomian18 showed 19.4% higher net photosynthetic rate (P(n), per unit leaf area) under K deficient solutions and this was associated with higher photochemical efficiency and faster export of soluble sugars from the phloem. The lower net P(n) of NuCOTN99(B) was attributed to higher capacity for nitrate assimilation and lower export of soluble sugars. Furthermore, NuCOTN99(B) showed 38.4% greater ETR/P(n) than Liaomian18 under K deficiency, indicating that more electrons were driven to other sinks. Higher superoxide dismutase (SOD) and lower catalase (CAT) and ascorbate peroxidase (APX) activities resulted in higher levels of reactive oxygen species (ROS; e.g. O(2)(-)and H(2)O(2)) in NuCOTN99(B) relative to Liaomian18. Thus, the K inefficiency of NuCOTN99(B), indicated by lower biomass and net P(n) under K deficiency, was associated with excessively high nitrogen assimilation, lower export of carbon assimilates, and greater ROS accumulation in the leaf. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

The oxygen deficient Ruddlesden-Popper La3Ni2O7-δ (δ = 0.65) phase: Structure and properties

International Nuclear Information System (INIS)

Poltavets, Viktor V.; Lokshin, Konstantin A.; Egami, Takeshi; Greenblatt, Martha

2006-01-01

La 3 Ni 2 O 7-δ (δ = 0.65) was synthesized by hydrogen reduction of the parent La 3 Ni 2 O 7 Ruddlesden-Popper nickelate. The crystal structure of La 3 Ni 2 O 6.35 (space group: I4/mmm, a = 3.8742 (1) A and c = 20.055 (1) A) has been determined from powder neutron diffraction data by the Rietveld method for the first time. The oxygen vacancies are located in the LaO x planes between two of the NiO 2 layers. Removal of these oxygen atoms from the parent phase results in a significant (∼0.4 A) shrinkage of the perovskite block along c-direction and splitting of the Ni position. The major part of Ni cations is surrounded by five oxygen atoms forming square pyramids, while the rest are coordinated to six octahedrally arranged oxygen atoms. Over the 170-400 K temperature range, the conductivity of La 3 Ni 2 O 6.35 follows Mott's variable range hopping model modified for a 2D case

Deficiency of Double-Strand DNA Break Repair Does Not Impair Mycobacterium tuberculosis Virulence in Multiple Animal Models of Infection

OpenAIRE

Heaton, Brook E.; Barkan, Daniel; Bongiorno, Paola; Karakousis, Petros C.; Glickman, Michael S.

2014-01-01

Mycobacterium tuberculosis persistence within its human host requires mechanisms to resist the effector molecules of host immunity, which exert their bactericidal effects through damaging pathogen proteins, membranes, and DNA. Substantial evidence indicates that bacterial pathogens, including M. tuberculosis, require DNA repair systems to repair the DNA damage inflicted by the host during infection, but the role of double-strand DNA break (DSB) repair systems is unclear. Double-strand DNA bre...

Dissimilatory nitrate reduction by Aspergillus terreus isolated from the seasonal oxygen minimum zone in the Arabian Sea.

Science.gov (United States)

Stief, Peter; Fuchs-Ocklenburg, Silvia; Kamp, Anja; Manohar, Cathrine-Sumathi; Houbraken, Jos; Boekhout, Teun; de Beer, Dirk; Stoeck, Thorsten

2014-02-11

A wealth of microbial eukaryotes is adapted to life in oxygen-deficient marine environments. Evidence is accumulating that some of these eukaryotes survive anoxia by employing dissimilatory nitrate reduction, a strategy that otherwise is widespread in prokaryotes. Here, we report on the anaerobic nitrate metabolism of the fungus Aspergillus terreus (isolate An-4) that was obtained from sediment in the seasonal oxygen minimum zone in the Arabian Sea, a globally important site of oceanic nitrogen loss and nitrous oxide emission. Axenic incubations of An-4 in the presence and absence of oxygen and nitrate revealed that this fungal isolate is capable of dissimilatory nitrate reduction to ammonium under anoxic conditions. A ¹⁵N-labeling experiment proved that An-4 produced and excreted ammonium through nitrate reduction at a rate of up to 175 nmol ¹⁵NH₄⁺ g⁻¹ protein h⁻¹. The products of dissimilatory nitrate reduction were ammonium (83%), nitrous oxide (15.5%), and nitrite (1.5%), while dinitrogen production was not observed. The process led to substantial cellular ATP production and biomass growth and also occurred when ammonium was added to suppress nitrate assimilation, stressing the dissimilatory nature of nitrate reduction. Interestingly, An-4 used intracellular nitrate stores (up to 6-8 μmol NO₃⁻ g⁻¹ protein) for dissimilatory nitrate reduction. Our findings expand the short list of microbial eukaryotes that store nitrate intracellularly and carry out dissimilatory nitrate reduction when oxygen is absent. In the currently spreading oxygen-deficient zones in the ocean, an as yet unexplored diversity of fungi may recycle nitrate to ammonium and nitrite, the substrates of the major nitrogen loss process anaerobic ammonium oxidation, and the potent greenhouse gas nitrous oxide.

A determination of the oxygen non-stoichiometry of the oxygen storage materials LnBaMn2O5+δ (Ln=Gd, Pr)

Science.gov (United States)

Jeamjumnunja, Kannika; Gong, Wenquan; Makarenko, Tatyana; Jacobson, Allan J.

2016-07-01

The A-site ordered double-perovskite oxides, LnBaMn2O5+δ (Ln=Gd, Pr), were synthesized and investigated to understand the effect of A site cation substitution on the oxygen storage properties of these materials. The present results are compared with our previous data for YBaMn2O5+δ. The results clearly reveal that changing the Ln cation strongly influences the oxidation/reduction behavior of LnBaMn2O5+δ. Based on thermogravimetric analysis data, oxygen uptake begins at lower temperatures in both air and oxygen in compounds with Ln3+ ions larger than Y3+. These oxides exhibit almost complete and reversible oxygen uptake/release between fully-reduced LnBaMn2O5 and fully-oxidized LnBaMn2O6 during changes of the oxygen partial pressure between air and 1.99% H2/Ar. In addition, the oxygen non-stoichiometries of GdBaMn2O5+δ and PrBaMn2O5+δ were determined as a function of pO2 at 600, 650, 700 and 750 °C by Coulometric titration at near-equilibrium conditions. The results confirm that these materials have two distinct phases on oxidation/reduction with δ≈0, 0.5 and a third phase with a range of composition with an oxygen content (5+δ) approaching 6. The stabilities of the LnBaMn2O5+δ phases extend over a wide range of oxygen partial pressures (∼10-25≤pO2 (atm)≤∼1) depending on temperature. Isothermal experiments show that the larger the Ln3+ cation the lower pO2 for phase conversion. At some temperatures and pO2 conditions, the LnBaMn2O5+δ compounds are unstable with respect to decomposition to BaMnO3-δ and LnMnO3. This instability is more apparent in Coulometric titration experiments than in thermogravimetric analysis. The Coulometric titration experiments are necessarily slow in order to achieve equilibrium oxygen compositions.

Quantitative determination of localized tissue oxygen concentration in vivo by two-photon excitation phosphorescence lifetime measurements

NARCIS (Netherlands)

Mik, Egbert G.; van Leeuwen, Ton G.; Raat, Nicolaas J.; Ince, Can

2004-01-01

This study describes the use of two-photon excitation phosphorescence lifetime measurements for quantitative oxygen determination in vivo. Doubling the excitation wavelength of Pd-porphyrin from visible light to the infrared allows for deeper tissue penetration and a more precise and confined

FBH1 co-operates with MUS81 in inducing DNA double-strand breaks and cell death following replication stress

DEFF Research Database (Denmark)

Fugger, Kasper; Chu, Wai Kit; Haahr, Peter

2013-01-01

The molecular events occurring following the disruption of DNA replication forks are poorly characterized, despite extensive use of replication inhibitors such as hydroxyurea in the treatment of malignancies. Here, we identify a key role for the FBH1 helicase in mediating DNA double-strand break...... formation following replication inhibition. We show that FBH1-deficient cells are resistant to killing by hydroxyurea, and exhibit impaired activation of the pro-apoptotic factor p53, consistent with decreased DNA double-strand break formation. Similar findings were obtained in murine ES cells carrying...... of replication stress. Our data suggest that FBH1 helicase activity is required to eliminate cells with excessive replication stress through the generation of MUS81-induced DNA double-strand breaks....

Iron Refractory Iron Deficiency Anaemia: A Rare Cause of Iron Deficiency Anaemia

LENUS (Irish Health Repository)

McGrath, T

2018-01-01

We describe the case of a 17-month-old boy with a hypochromic microcytic anaemia, refractory to oral iron treatment. After exclusion of dietary and gastrointestinal causes of iron deficiency, a genetic cause for iron deficiency was confirmed by finding two mutations in the TMPRSS6 gene, consistent with a diagnosis of iron-refractory iron deficiency anaemia (IRIDA).

Deficiency of the Chemotactic Factor Inactivator in Human Sera with α1-Antitrypsin Deficiency

Science.gov (United States)

Ward, Peter A.; Talamo, Richard C.

1973-01-01

As revealed by appropriate fractionation procedures, human serum deficient in α1-antitrypsin (α1-AT) is also deficient in the naturally occurring chemotactic factor inactivator. These serum donors had severe pulmonary emphysema. Serum from patients with clinically similar pulmonary disease, but with presence of α1-AT in the serum, showed no such deficiency of the chemotactic factor inactivator. When normal human serum and α1-AT-deficient human sera are chemotactically activated by incubation with immune precipitates, substantially more chemotactic activity is generated in α1-AT-deficient serum. These data indicate that in α1-AT-deficient serum there is an imbalance in the generation and control of chemotactic factors. It is suggested that the theory regarding development of pulmonary emphysema in patients lacking the α1-antitrypsin in their serum should be modified to take into account a deficiency of the chemotactic factor inactivator. PMID:4683887

Magnetization and flux pinning in high-Tc cuprates: Irradiated and oxygen deficient materials

International Nuclear Information System (INIS)

Thompson, J.R.; Civale, L.; Marwick, A.D.; Holtzberg, F.

1992-11-01

This work surveys recent studies of the intragrain current density J and vortex pinning in high Tc superconductors. Materials include Y 1 Ba 2 Cu 3 O 7-δ and Bi 2 Sr 2 Ca 1 Cu 2 O 8 single crystals and aligned polycrystals. To probe the flux pinning, we modified the strength, number, and morphology of defects. Varying the oxygen content (7-δ) in YBa 2 Cu 3 O 7-δ or irradiating the materials with ions, having either light or heavy masses, gives systematic changes in the character of the all-important defects

Iron-Deficiency Anemia

Medline Plus

Full Text Available ... your doctor may recommend you eat heart-healthy foods or control other conditions that can cause iron-deficiency anemia. Blood tests to screen for iron-deficiency anemia To screen ...

Iron-Deficiency Anemia

Medline Plus

Full Text Available ... from developing iron-deficiency anemia. Foods that are good sources of iron include dried beans, dried fruits, eggs, lean red meat, ... signs of iron-deficiency anemia include: Brittle nails ...

Fire Safety Deficiencies

Data.gov (United States)

U.S. Department of Health & Human Services — A list of all fire safety deficiencies currently listed on Nursing Home Compare, including the nursing home that received the deficiency, the associated inspection...

Methods of Blood Oxygen Level-Dependent Magnetic Resonance Imaging Analysis for Evaluating Renal Oxygenation

Directory of Open Access Journals (Sweden)

Fen Chen

2018-03-01

Full Text Available Blood oxygen level-dependent magnetic resonance imaging (BOLD MRI has recently been utilized as a noninvasive tool for evaluating renal oxygenation. Several methods have been proposed for analyzing BOLD images. Regional ROI selection is the earliest and most widely used method for BOLD analysis. In the last 20 years, many investigators have used this method to evaluate cortical and medullary oxygenation in patients with ischemic nephropathy, hypertensive nephropathy, diabetic nephropathy, chronic kidney disease (CKD, acute kidney injury and renal allograft rejection. However, clinical trials of BOLD MRI using regional ROI selection revealed that it was difficult to distinguish the renal cortico-medullary zones with this method, and that it was susceptible to observer variability. To overcome these deficiencies, several new methods were proposed for analyzing BOLD images, including the compartmental approach, fractional hypoxia method, concentric objects (CO method and twelve-layer concentric objects (TLCO method. The compartmental approach provides an algorithm to judge whether the pixel belongs to the cortex or medulla. Fractional kidney hypoxia, measured by using BOLD MRI, was negatively correlated with renal blood flow, tissue perfusion and glomerular filtration rate (GFR in patients with atherosclerotic renal artery stenosis. The CO method divides the renal parenchyma into six or twelve layers of thickness in each coronal slice of BOLD images and provides a R2* radial profile curve. The slope of the R2* curve associated positively with eGFR in CKD patients. Indeed, each method invariably has advantages and disadvantages, and there is generally no consensus method so far. Undoubtedly, analytic approaches for BOLD MRI with better reproducibility would assist clinicians in monitoring the degree of kidney hypoxia and thus facilitating timely reversal of tissue hypoxia.

Iron-Deficiency Anemia

Medline Plus

Full Text Available ... for iron-deficiency anemia. Lifestyle habits Certain lifestyle habits may increase your risk for iron-deficiency anemia, including: Vegetarian or vegan eating patterns. Not eating enough iron-rich foods, such ...

Factor VII deficiency

Science.gov (United States)

... this page: //medlineplus.gov/ency/article/000548.htm Factor VII deficiency To use the sharing features on this page, please enable JavaScript. Factor VII (seven) deficiency is a disorder caused by a ...

Reduced repair of potentially lethal radiation damage in glutathione synthetase-deficient human fibroblasts after X-irradiation

International Nuclear Information System (INIS)

Midander, J.; Revesz, L.; Deschavanne, P.J.; Debieu, D.; Malaise, E.P.

1986-01-01

Using a human fibroblast strain deficient in glutathione synthetase and a related proficient control strain, the role of glutathione (GSH) in repair of potentially lethal damage (PLD) has been investigated in determining survival by plating cells immediately or 24 h after irradiation. After oxic or hypoxic irradiation, both cell strains repair radiation-induced damage. However, under hypoxic conditions, the proficient cells repair PLD as well as under oxic conditions while the deficient cells repair less PLD after irradiation under hypoxic than under oxic conditions. Therefore, the oxygen enhancement ratio (o.e.r.) for proficient cells is similar whether the cells are plated immediately or 24 h later (2.0 and 2.13, respectively). In contrast, the o.e.r. for deficient cells is lower when the cells are plated 24 h after irradiation than when they are plated immediately thereafter (1.16 as compared to 1.55). The results indicate that GSH is involved in PLD repair and, in particular, in the repair of damage induced by radiation delivered under hypoxic conditions. (author)

Acute dietary zinc deficiency before conception compromises oocyte epigenetic programming and disrupts embryonic development.

Science.gov (United States)

Tian, X; Diaz, F J

2013-04-01

Recent findings show that zinc is an important factor necessary for regulating the meiotic cell cycle and ovulation. However, the role of zinc in promoting oocyte quality and developmental potential is not known. Using an in vivo model of acute dietary zinc deficiency, we show that feeding a zinc deficient diet (ZDD) for 3-5 days before ovulation (preconception) dramatically disrupts oocyte chromatin methylation and preimplantation development. There was a dramatic decrease in histone H3K4 trimethylation and global DNA methylation in zinc deficient oocytes. Moreover, there was a 3-20 fold increase in transcript abundance of repetitive elements (Iap, Line1, Sineb1, Sineb2), but a decrease in Gdf9, Zp3 and Figla mRNA. Only 53% and 8% of mature eggs reached the 2-cell stage after IVF in animals receiving a 3 and 5 days ZDD, respectively, while a 5 day ZDD in vivo reduced the proportion of 2-cells to 49%. In vivo fertilized 2-cell embryos cultured in vitro formed fewer (38%) blastocysts compared to control embryos (74%). Likewise, fewer blastocyst and expanded blastocyst were collected from the reproductive tract of zinc deficient animals on day 3.5 of pregnancy. This could be due to a decrease in Igf2 and H19 mRNA in ZDD blastocyst. Supplementation with a methyl donor (SAM) during IVM restored histone H3K4me3 and doubled the IVF success rate from 17% to 43% in oocytes from zinc deficient animals. Thus, the terminal period of oocyte development is extremely sensitive to perturbation in dietary zinc availability. Copyright © 2013 Elsevier Inc. All rights reserved.

Toward reassessing data-deficient species.

Science.gov (United States)

Bland, Lucie M; Bielby, Jon; Kearney, Stephen; Orme, C David L; Watson, James E M; Collen, Ben

2017-06-01

One in 6 species (13,465 species) on the International Union for Conservation of Nature (IUCN) Red List is classified as data deficient due to lack of information on their taxonomy, population status, or impact of threats. Despite the chance that many are at high risk of extinction, data-deficient species are typically excluded from global and local conservation priorities, as well as funding schemes. The number of data-deficient species will greatly increase as the IUCN Red List becomes more inclusive of poorly known and speciose groups. A strategic approach is urgently needed to enhance the conservation value of data-deficient assessments. To develop this, we reviewed 2879 data-deficient assessments in 6 animal groups and identified 8 main justifications for assigning data-deficient status (type series, few records, old records, uncertain provenance, uncertain population status or distribution, uncertain threats, taxonomic uncertainty, and new species). Assigning a consistent set of justification tags (i.e., consistent assignment to assessment justifications) to species classified as data deficient is a simple way to achieve more strategic assessments. Such tags would clarify the causes of data deficiency; facilitate the prediction of extinction risk; facilitate comparisons of data deficiency among taxonomic groups; and help prioritize species for reassessment. With renewed efforts, it could be straightforward to prevent thousands of data-deficient species slipping unnoticed toward extinction. © 2016 Society for Conservation Biology.

Mutagenicity and co-mutagenicity of static magnetic field in SOD-deficient Escherichia coli

International Nuclear Information System (INIS)

Yoshie, Sachiko; Ikehata, Masateru; Hayakawa, Toshio; Hirota, Noriyuki; Takemura, Taro; Minowa, Takashi; Hanagata, Nobutaka

2008-01-01

The effects of strong static magnetic fields (SMFs) on mutagenesis related to reactive oxygen species were investigated. To estimate mutagenicity of SMFs, superoxide dismutase (SOD)-deficient Escherichia coli QC774 and its parental strain GC4468 were employed. Tester strains were exposed to 5, 10 and 13 T SMFs for 24 hr at 37 C degrees in LB medium. After exposure, mutation frequency on thymine synthesis genes was determined for evaluation of mutagenicity of SMFs exposure. In the result, no statistically significant difference in mutation frequency on thymine synthesis genes was observed between SMF-exposed cells and unexposed cells in all of magnetic flux densities. Furthermore, SMFs up to 13 T did not affect mutagenicity of plumbagine under its presence of 25 μM, respectively. It suggests that SMF did not have either mutagenicity or co-mutagenicity in SOD-deficient and its parental E. coli strains under the condition in this study. (author)

Anemia, Iron Deficiency and Iodine Deficiency among Nepalese School Children.

Science.gov (United States)

Khatiwada, Saroj; Lamsal, Madhab; Gelal, Basanta; Gautam, Sharad; Nepal, Ashwini Kumar; Brodie, David; Baral, Nirmal

2016-07-01

To assess iodine and iron nutritional status among Nepalese school children. A cross-sectional, community based study was conducted in the two districts, Ilam (hilly region) and Udayapur (plain region) of eastern Nepal. A total of 759 school children aged 6-13 y from different schools within the study areas were randomly enrolled. A total of 759 urine samples and 316 blood samples were collected. Blood hemoglobin level, serum iron, total iron binding capacity and urinary iodine concentration was measured. Percentage of transferrin saturation was calculated using serum iron and total iron binding capacity values. The mean level of hemoglobin, serum iron, total iron binding capacity, transferrin saturation and median urinary iodine excretion were 12.29 ± 1.85 g/dl, 70.45 ± 34.46 μg/dl, 386.48 ± 62.48 μg/dl, 19.94 ± 12.07 % and 274.67 μg/L respectively. Anemia, iron deficiency and iodine deficiency (urinary iodine excretion iron deficient children. Iron deficiency and anemia are common in Nepalese children, whereas, iodine nutrition is more than adequate. Low urinary iodine excretion was common in iron deficiency and anemia.

Iron-Deficiency Anemia

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Full Text Available ... deficiency anemia can cause serious complications, including heart failure and development delays in children. Explore this Health ... to iron-deficiency anemia include: End-stage kidney failure, where there is blood loss during dialysis. People ...

Iron-Deficiency Anemia

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Full Text Available ... view the colon directly. What if my doctor thinks something else is causing my iron-deficiency anemia? ... deficiency anemia early in life affects later behavior, thinking, and mood during adolescence. Treating anemia in premature ...

Iron-Deficiency Anemia

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Full Text Available ... deficiency anemia can cause serious complications, including heart failure and development delays in children. Explore this Health ... lead to iron-deficiency anemia include: End-stage kidney failure, where there is blood loss during dialysis. ...

Iron-Deficiency Anemia

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Full Text Available ... iron-deficiency anemia. These conditions include: Intestinal and digestive conditions, such as celiac disease; inflammatory bowel diseases, ... iron-deficiency anemia , such as bleeding in the digestive or urinary tract or heavy menstrual bleeding, your ...

Iron-Deficiency Anemia

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Full Text Available ... mg and women need 18 mg. After age 51, both men and women need 8 mg. Pregnant ... for iron-deficiency anemia. Learn about exciting research areas that NHLBI is exploring about iron-deficiency anemia. ...

Iron-Deficiency Anemia

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Full Text Available ... fatigue or tiredness, shortness of breath, or chest pain. If your doctor diagnoses you with iron-deficiency ... Common symptoms of iron-deficiency anemia include: Chest pain Coldness in the hands and feet Difficulty concentrating ...

Iron-Deficiency Anemia

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Full Text Available ... heart failure . Increased risk of infections Motor or cognitive development delays in children Pregnancy complications, such as ... for iron-deficiency anemia. Learn about exciting research areas that NHLBI is exploring about iron-deficiency anemia. ...

Iron-Deficiency Anemia

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Iron-Deficiency Anemia

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Full Text Available ... learning how having iron-deficiency anemia early in life affects later behavior, thinking, and mood during adolescence. ... iron-deficiency anemia in blood donors affects the quality of donated red blood cells, such as how ...

Iron-Deficiency Anemia

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Full Text Available ... iron-deficiency anemia in blood donors affects the quality of donated red blood cells, such as how ... Cells From Iron-deficient Donors: Recovery and Storage Quality. Learn more about participating in a clinical trial . ...

Iron-Deficiency Anemia

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Full Text Available ... leaving cells where it is stored or from being absorbed in the duodenum, the first part of ... treatments for iron-deficiency anemia. Living With After being diagnosed with iron-deficiency anemia, it is important ...

Low energy consumption method for separating gaseous mixtures and in particular for medium purity oxygen production

Science.gov (United States)

Jujasz, Albert J.; Burkhart, James A.; Greenberg, Ralph

1988-01-01

A method for the separation of gaseous mixtures such as air and for producing medium purity oxygen, comprising compressing the gaseous mixture in a first compressor to about 3.9-4.1 atmospheres pressure, passing said compressed gaseous mixture in heat exchange relationship with sub-ambient temperature gaseous nitrogen, dividing the cooled, pressurized gaseous mixture into first and second streams, introducing the first stream into the high pressure chamber of a double rectification column, separating the gaseous mixture in the rectification column into a liquid oxygen-enriched stream and a gaseous nitrogen stream and supplying the gaseous nitrogen stream for cooling the compressed gaseous mixture, removing the liquid oxygen-enriched stream from the low pressure chamber of the rectification column and pumping the liquid, oxygen-enriched steam to a predetermined pressure, cooling the second stream, condensing the cooled second stream and evaporating the oxygen-enriched stream in an evaporator-condenser, delivering the condensed second stream to the high pressure chamber of the rectification column, and heating the oxygen-enriched stream and blending the oxygen-enriched stream with a compressed blend-air stream to the desired oxygen concentration.

The treatment of iron deficiency without anaemia (in otherwise healthy persons).

Science.gov (United States)

Clénin, German E

2017-06-21

Iron deficiency is the most widespread and frequent nutritional disorder in the world. It affects a high proportion of children and women in developing countries and is also significantly prevalent in the industrialised world, with a clear predominance in adolescents and menstruating females. Iron is essential for optimal cognitive function and physical performance, not only as a binding site of oxygen but also as a critical constituent of many enzymes. Therefore iron deficiency at all its levels - nonanaemic iron deficiency, iron deficiency with microcytosis or hypochromia and iron deficiency anaemia - should be treated. In the presence of normal stores, however, preventative iron administration is inefficient, has side effects and seems to be harmful. In symptomatic patients with fatigue or in a population at risk for iron deficiency (adolescence, heavy or prolonged menstruation, high performance sport, vegetarian or vegan diet, eating disorder, underweight), a baseline set of blood tests including haemoglobin concentration, haematocrit, mean cellular volume, mean cellular haemoglobin, percentage of hypochromic erythrocytes and serum ferritin levels are important to monitor iron deficiency. To avoid false negative results (high ferritin levels in spite of iron deficiency), an acute phase reaction should be excluded by history and measurement of C-reactive protein. An algorithm leads through this diagnostic process and the decision making for a possible treatment. For healthy males and females aged >15 years, a ferritin cut-off of 30 µg/l is appropriate. For children from 6-12 years and younger adolescents from 12-15 years, cut-offs of 15 and 20 µg/l, respectively, are recommended. As a first step in treatment, counselling and oral iron therapy are usually combined. Integrating haem and free iron regularly into the diet, looking for enhancers and avoiding inhibitors of iron uptake is beneficial. In order to prevent reduced compliance, mainly as a result of

Heart failure in patients with kidney disease and iron deficiency; the role of iron therapy.

Science.gov (United States)

Cases Amenós, Aleix; Ojeda López, Raquel; Portolés Pérez, José María

Chronic kidney disease and anaemia are common in heart failure (HF) and are associated with a worse prognosis in these patients. Iron deficiency is also common in patients with HF and increases the risk of morbidity and mortality, regardless of the presence or absence of anaemia. While the treatment of anaemia with erythropoiesis-stimulating agents in patients with HF have failed to show a benefit in terms of morbidity and mortality, treatment with IV iron in patients with HF and reduced ejection fraction and iron deficiency is associated with clinical improvement. In a posthoc analysis of a clinical trial, iron therapy improved kidney function in patients with HF and iron deficiency. In fact, the European Society of Cardiology's recent clinical guidelines on HF suggest that in symptomatic patients with reduced ejection fraction and iron deficiency, treatment with IV ferric carboxymaltose should be considered to improve symptoms, the ability to exercise and quality of life. Iron plays a key role in oxygen storage (myoglobin) and in energy metabolism, and there are pathophysiological bases that explain the beneficial effect of IV iron therapy in patients with HF. All these aspects are reviewed in this article. Copyright © 2017 Sociedad Española de Nefrología. Published by Elsevier España, S.L.U. All rights reserved.

Enhanced Decoupled Double Synchronous Reference Frame Current Controller for Unbalanced Grid-Voltage Conditions

DEFF Research Database (Denmark)

Reyes, M.; Rodriguez, Pedro; Vazquez, S.

2012-01-01

. In these codes, the injection of positive- and negative-sequence current components becomes necessary for fulfilling, among others, the low-voltage ride-through requirements during balanced and unbalanced grid faults. However, the performance of classical dq current controllers, applied to power converters......, under unbalanced grid-voltage conditions is highly deficient, due to the unavoidable appearance of current oscillations. This paper analyzes the performance of the double synchronous reference frame controller and improves its structure by adding a decoupling network for estimating and compensating...

Antiferromagnetic ordering states of oxygen-deficient NdBa₂Cu₃O_6+x and Nd_1+yBa_2-yCu₃O_6+x single crystals

DEFF Research Database (Denmark)

Brecht, E.; Schweiss, P.; Wolf, T.

1999-01-01

The paper describes a study of the antiferromagnetic ordering of oxygen-deficient Nd1 + yBa2 - yCu3O6 + x single crystals. In pure, stoichiometric samples, y = 0, with different oxygen contents x in the Cu(1) plane (0.02AFI) phase appears to be stable down to 316 m...... of this reordering suggests that the Nd3+ ions on Ba sites are very effective defects forcing the AFIAFII reordering. The mechanism of reordering is explained in terms of the creation of Cu2+ moments within the Cu(1) layer due to the Nd3+ ions on Ba sites, which via polarization lead to an effective ferromagnetic...

Iron-Deficiency Anemia

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Full Text Available ... iron-deficiency anemia. Search the NIH Research Portfolio Online Reporting Tools (RePORT) to learn about research that ... iron-deficiency anemia in blood donors affects the quality of donated red blood cells, such as how ...

A preliminary investigation into the extent of increased radioresistance or hyper-radiosensitivity in cells of hamster cell lines known to be deficient in DNA repair

International Nuclear Information System (INIS)

Skov, K.; Marples, B.; Matthews, J.B.; Zhou, H.; Joiner, M.C.

1994-01-01

The response to low doses of X rays was assessed in cells of three hamster cell lines which are defective in DNA repair and was compared with their parental lines. Cells of the V79-derived double-strand break repair-deficient line XR-V15B showed no radioresistance in the 0.5-Gy range compared with the V79B wild type, but instead showed an exponential response. Cells of the single-strand break repair-deficient line EM9 showed hyper-radiosensitivity and exhibited increased radioresistance. Most interestingly, cells of the UV-20 cell line appeared to respond exponentially, as a continuation of the hyper-radiosensitive portion of the curve, with no evidence of increased radioresistance. This line is defective in an incision step of excision repair and is sensitive to crosslinking agents. Further studies are warranted to address the possible role of single- and double-strand break repair and excision repair in hyper-radiosensitivity and increased radioresistance. 24 refs., 4 figs

[Vitamin deficiencies in breastfed children due to maternal dietary deficiency

NARCIS (Netherlands)

Kollee, L.A.A.

2006-01-01

Dietary deficiencies of vitamin B12 and vitamin D during pregnancy and lactation may result in health problems in exclusively breastfed infants. Vitamin-B12 deficiency in these infants results in irritability, anorexia and failure to thrive during the first 4-8 months of life. Severe and permanent

Iron-Deficiency Anemia

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Full Text Available ... en español Iron-deficiency anemia is a common type of anemia that occurs if you do not ... iron-deficiency anemia and help rule out other types of anemia. Treatment will explain treatment-related complications ...

Iron-Deficiency Anemia

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Full Text Available ... other conditions that can cause iron-deficiency anemia. Blood tests to screen for iron-deficiency anemia To screen ... check the size of your liver and spleen. Blood tests Based on results from blood tests to screen ...

Iron-Deficiency Anemia

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Full Text Available ... blood cells. Iron-deficiency anemia usually develops over time because your body’s intake of iron is too ... clamping of your newborn’s umbilical cord at the time of delivery. This may help prevent iron-deficiency ...

Oxygen fugacity control in piston-cylinder experiments: a re-evaluation

Science.gov (United States)

Jakobsson, Sigurdur; Blundy, Jon; Moore, Gordon

2014-06-01

Jakobsson (Contrib Miner Petrol 164(3):397-407, 2012) investigated a double capsule assembly for use in piston-cylinder experiments that would allow hydrous, high-temperature, and high-pressure experiments to be conducted under controlled oxygen fugacity conditions. Using a platinum outer capsule containing a metal oxide oxygen buffer (Ni-NiO or Co-CoO) and H2O, with an inner gold-palladium capsule containing hydrous melt, this study was able to compare the oxygen fugacity imposed by the outer capsule oxygen buffer with an oxygen fugacity estimated by the AuPdFe ternary system calibrated by Barr and Grove (Contrib Miner Petrol 160(5):631-643, 2010). H2O loss or gain, as well as iron loss to the capsule walls and carbon contamination, is often observed in piston-cylinder experiments and often go unexplained. Only a few have attempted to actually quantify various aspects of these changes (Brooker et al. in Am Miner 83(9-10):985-994, 1998; Truckenbrodt and Johannes in Am Miner 84:1333-1335, 1999). It was one of the goals of Jakobsson (Contrib Miner Petrol 164(3):397-407, 2012) to address these issues by using and testing the AuPdFe solution model of Barr and Grove (Contrib Miner Petrol 160(5):631-643, 2010), as well as to constrain the oxygen fugacity of the inner capsule. The oxygen fugacities of the analyzed melts were assumed to be equal to those of the solid Ni-NiO and Co-CoO buffers, which is incorrect since the melts are all undersaturated in H2O and the oxygen fugacities should therefore be lower than that of the buffer by 2 log.

Iron-Deficiency Anemia

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Full Text Available ... blocks the intestine from taking up iron. Other medical conditions Other medical conditions that may lead to iron-deficiency anemia ... daily amount of iron. If you have other medical conditions that cause iron-deficiency anemia , such as ...

Iron-Deficiency Anemia

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Full Text Available ... anemia if you have certain risk factors , including pregnancy. To prevent iron-deficiency anemia, your doctor may recommend you eat heart-healthy foods or control other conditions that can cause iron-deficiency anemia. Blood tests to screen for ...

Iron-Deficiency Anemia

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Full Text Available ... loss and lead to iron-deficiency anemia. Common causes of blood loss that lead to iron-deficiency anemia include: Bleeding in your GI tract, from an ulcer, colon cancer, or regular use of medicines such as aspirin ...

Iron-Deficiency Anemia

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Full Text Available ... for iron-deficiency anemia. Lifestyle habits Certain lifestyle habits may increase your risk for iron-deficiency anemia, including: Vegetarian or vegan eating patterns. Not eating enough iron-rich foods, such as meat and fish, may result in ...

Iron-Deficiency Anemia

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Full Text Available ... anemia. Return to Signs, Symptoms, and Complications to review signs and symptoms as well as complications from iron-deficiency ... NIH]) Heavy Menstrual Bleeding (Centers for Disease Control and ... Dietary Supplement Fact Sheet (NIH) Iron-Deficiency Anemia (National Library ...

Iron-Deficiency Anemia

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Full Text Available ... be at risk for iron-deficiency anemia. Lifestyle habits Certain lifestyle habits may increase your risk for iron-deficiency anemia, ... you are experiencing side effects such as a bad metallic taste, vomiting, diarrhea, constipation, or upset stomach. ...

Iron-Deficiency Anemia

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Full Text Available ... how we are using current research and advancing research to prevent iron-deficiency anemia. Participate in NHLBI Clinical Trials will explain our ongoing clinical studies that are investigating prevention strategies for iron-deficiency anemia. Signs, Symptoms, and Complications ...

Progression from isolated growth hormone deficiency to combined pituitary hormone deficiency.

Science.gov (United States)

Cerbone, Manuela; Dattani, Mehul T

2017-12-01

Growth hormone deficiency (GHD) can present at any time of life from the neonatal period to adulthood, as a result of congenital or acquired insults. It can present as an isolated problem (IGHD) or in combination with other pituitary hormone deficiencies (CPHD). Pituitary deficits can evolve at any time from GHD diagnosis. The number, severity and timing of occurrence of additional endocrinopathies are highly variable. The risk of progression from IGHD to CPHD in children varies depending on the etiology (idiopathic vs organic). The highest risk is displayed by children with abnormalities in the Hypothalamo-Pituitary (H-P) region. Heterogeneous data have been reported on the type and timing of onset of additional pituitary hormone deficits, with TSH deficiency being most frequent and Diabetes Insipidus the least frequent additional deficit in the majority, but not all, of the studies. ACTH deficiency may gradually evolve at any time during follow-up in children or adults with childhood onset IGHD, particularly (but not only) in presence of H-P abnormalities and/or TSH deficiency. Hence there is a need in these patients for lifelong monitoring for ACTH deficiency. GH treatment unmasks central hypothyroidism mainly in patients with organic GHD, but all patients starting GH should have their thyroid function monitored closely. Main risk factors for development of CPHD include organic etiology, H-P abnormalities (in particular pituitary stalk abnormalities, empty sella and ectopic posterior pituitary), midline brain (corpus callosum) and optic nerves abnormalities, genetic defects and longer duration of follow-up. The current available evidence supports longstanding recommendations for the need, in all patients diagnosed with IGHD, of a careful and indefinite follow-up for additional pituitary hormone deficiencies. Copyright © 2017 Elsevier Ltd. All rights reserved.

L-Cysteine in vitro can restore cellular glutathione and inhibits the expression of cell adhesion molecules in G6PD-deficient monocytes.

Science.gov (United States)

Parsanathan, Rajesh; Jain, Sushil K

2018-04-06

L-Cysteine is a precursor of glutathione (GSH), a potent physiological antioxidant. Excess glucose-6-phosphate dehydrogenase (G6PD) deficiency in African Americans and low levels of L-cysteine diet in Hispanics can contributes to GSH deficiency and oxidative stress. Oxidative stress and monocyte adhesion was considered to be an initial event in the progression of vascular dysfunction and atherosclerosis. However, no previous study has investigated the contribution of GSH/G6PD deficiency to the expression of monocyte adhesion molecules. Using human U937 monocytes, this study examined the effect of GSH/G6PD deficiency and L-cysteine supplementation on monocyte adhesion molecules. G6PD/GSH deficiency induced by either siRNA or inhibitors (6AN/BSO, respectively) significantly (p adhesion molecules (ICAM-1, VCAM-1, SELL, ITGB1 and 2); NADPH oxidase (NOX), reactive oxygen species (ROS) and MCP-1 were upregulated, and decreases in levels of GSH, and nitric oxide were observed. The expression of ICAM-1 and VCAM-1 mRNA levels increased in high glucose, MCP-1 or TNF-α-treated G6PD-deficient compared to G6PD-normal cells. L-Cysteine treatment significantly (p adhesion molecules. Thus, GSH/G6PD deficiency increases susceptibility to monocyte adhesion processes, whereas L-cysteine supplementation can restore cellular GSH/G6PD and attenuates NOX activity and expression of cell adhesion molecules.

Iron-Deficiency Anemia

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Full Text Available ... exploring about iron-deficiency anemia. Read more New treatments for disorders that lead to iron-deficiency anemia. We are ... and other pathways. This could help develop new therapies for conditions that ... behavior, thinking, and mood during adolescence. Treating anemia in ...

Nutritional iron deficiency

NARCIS (Netherlands)

Zimmermann, M.B.; Hurrell, R.F.

2007-01-01

Iron deficiency is one of the leading risk factors for disability and death worldwide, affecting an estimated 2 billion people. Nutritional iron deficiency arises when physiological requirements cannot be met by iron absorption from diet. Dietary iron bioavailability is low in populations consuming

Stable silver nanoclusters electrochemically deposited on nitrogen-doped graphene as efficient electrocatalyst for oxygen reduction reaction

Science.gov (United States)

Jin, Shi; Chen, Man; Dong, Haifeng; He, Bingyu; Lu, Huiting; Su, Lei; Dai, Wenhao; Zhang, Qiaochu; Zhang, Xueji

2015-01-01

Metal nanoclusters exhibit unusually high catalytic activity toward oxygen reduction reaction (ORR) due to their small size and unique electronic structures. However, controllable synthesis of stable metal nanoclusters is a challenge, and the durability of metal clusters suffers from the deficiency of dissolution, aggregation, and sintering during catalysis reactions. Herein, silver nanoclusters (AgNCs) (diameter , which is vital in high performance fuel cells, batteries and nanodevices.

Singlet oxygen reactions with flavonoids. A theoretical-experimental study.

Science.gov (United States)

Morales, Javier; Günther, Germán; Zanocco, Antonio L; Lemp, Else

2012-01-01

Detection of singlet oxygen emission, λ(max) = 1270 nm, following laser excitation and steady-state methods were employed to measure the total reaction rate constant, k(T), and the reactive reaction rate constant, k(r), for the reaction between singlet oxygen and several flavonoids. Values of k(T) determined in deuterated water, ranging from 2.4×10(7) M(-1) s(-1) to 13.4×10(7) M(-1) s(-1), for rutin and morin, respectively, and the values measured for k(r), ranging from 2.8×10(5) M(-1) s(-1) to 65.7×10(5) M(-1) s(-1) for kaempferol and morin, respectively, being epicatechin and catechin chemically unreactive. These results indicate that all the studied flavonoids are good quenchers of singlet oxygen and could be valuable antioxidants in systems under oxidative stress, in particular if a flavonoid-rich diet was previously consumed. Analysis of the dependence of rate constant values with molecular structure in terms of global descriptors and condensed Fukui functions, resulting from electronic structure calculations, supports the formation of a charge transfer exciplex in all studied reactions. The fraction of exciplex giving reaction products evolves through a hydroperoxide and/or an endoperoxide intermediate produced by singlet oxygen attack on the double bond of the ring C of the flavonoid.

Singlet oxygen reactions with flavonoids. A theoretical-experimental study.

Directory of Open Access Journals (Sweden)

Javier Morales

Full Text Available Detection of singlet oxygen emission, λ(max = 1270 nm, following laser excitation and steady-state methods were employed to measure the total reaction rate constant, k(T, and the reactive reaction rate constant, k(r, for the reaction between singlet oxygen and several flavonoids. Values of k(T determined in deuterated water, ranging from 2.4×10(7 M(-1 s(-1 to 13.4×10(7 M(-1 s(-1, for rutin and morin, respectively, and the values measured for k(r, ranging from 2.8×10(5 M(-1 s(-1 to 65.7×10(5 M(-1 s(-1 for kaempferol and morin, respectively, being epicatechin and catechin chemically unreactive. These results indicate that all the studied flavonoids are good quenchers of singlet oxygen and could be valuable antioxidants in systems under oxidative stress, in particular if a flavonoid-rich diet was previously consumed. Analysis of the dependence of rate constant values with molecular structure in terms of global descriptors and condensed Fukui functions, resulting from electronic structure calculations, supports the formation of a charge transfer exciplex in all studied reactions. The fraction of exciplex giving reaction products evolves through a hydroperoxide and/or an endoperoxide intermediate produced by singlet oxygen attack on the double bond of the ring C of the flavonoid.

Ac-induced disruption of the doubleDs structure in tomato

NARCIS (Netherlands)

Rommens, Caius M.T.; Biezen, Erik A. van der; Ouwerkerk, Pieter B.F.; Nijkamp, H. John J.; Hille, Jacques

1991-01-01

The maize doubleDs element is stably maintained in the tomato genome. Upon the subsequent introduction of Ac into a plant containing doubleDs, disruption of the doubleDs structure and DNA rearrangements at the site of the doubleDs element were observed. No indications were obtained for excision of

Oxygen vacancies dependent phase transition of Y{sub 2}O{sub 3} films

Energy Technology Data Exchange (ETDEWEB)

Yu, Pengfei; Zhang, Kan [Department of Materials Science, State Key Laboratory of Superhard Materials, and Key Laboratory of Automobile Materials, MOE, Jilin University, Changchun 130012 (China); Huang, Hao [Titanium Alloys Lab. Beijing Institute of Aeronautical Materials, Beijing 81-15 100095 (China); Wen, Mao, E-mail: Wenmao225@jlu.edu.cn [Department of Materials Science, State Key Laboratory of Superhard Materials, and Key Laboratory of Automobile Materials, MOE, Jilin University, Changchun 130012 (China); Li, Quan; Zhang, Wei; Hu, Chaoquan [Department of Materials Science, State Key Laboratory of Superhard Materials, and Key Laboratory of Automobile Materials, MOE, Jilin University, Changchun 130012 (China); Zheng, Weitao, E-mail: WTZheng@jlu.edu.cn [Department of Materials Science, State Key Laboratory of Automotive Simulation and Control and Key Laboratory of Automobile Materials, MOE, Jilin University, Changchun 130012 (China)

2017-07-15

Highlights: • Oxygen vacancies for Y{sub 2}O{sub 3} films increase monotonously with increasing T{sub s}. • Oxygen vacancies can promote the nucleation of monoclinic phase. • That monoclinic phase with oxygen deficiency is not thermodynamic stable at high temperature. • Phase transition from monoclinic to oxygen defective occurs at high concentrations of oxygen vacancies. • High hardness just appears in Y{sub 2}O{sub 3} films with mixed phase configurations. - Abstract: Y{sub 2}O{sub 3} films have great application potential in high-temperature metal matrix composite and nuclear engineering, used as interface diffusion and reaction barrier coating owing to their excellent thermal and chemical stability, high melting point and extremely negative Gibbs formation energy, and thus their structural and mechanical properties at elevated temperature are especially important. Oxygen vacancies exist commonly in yttrium oxide (Y{sub 2}O{sub 3}) thin films and act strongly on the phase structure and properties, but oxygen vacancies dependent phase transition at elevated temperature has not been well explored yet. Y{sub 2}O{sub 3} thin films with different oxygen vacancy concentrations have been achieved by reactive sputtering through varying substrate temperature (T{sub s}), in which oxygen vacancies increase monotonously with increasing T{sub s}. For as-deposited Y{sub 2}O{sub 3} films, oxygen vacancies present at high T{sub s} can promote the nucleation of monoclinic phase, meanwhile, high T{sub s} can induce the instability of monoclinic phase. Thus their competition results in forming mixed phases of cubic and monoclinic at high T{sub s}. During vacuum annealing at 1000 °C, a critical oxygen vacancy concentration is observed, below which phase transition from monoclinic to cubic takes place, and above which phase transfer from monoclinic to the oxygen defective phase (ICDD file no. 39-1063), accompanying by stress reversal from compressive to tensile and

Comparative studies on two formulas of double fortified salt and it’s impact on anemia control

Directory of Open Access Journals (Sweden)

S Nair

2015-12-01

address the issue in public health scenario.The vulnerable groups are the most affected ones. Even though the supplementation program is in place, compliance is not at its optimal levels. India already has an existing program on USI norms to supply iodized salt to all populations. Therefore, double fortification of salt with iron and iodine as a tool to combat these deficiencies was the best thought approach by various scientists. The efforts towards producing a stable formula containing iron merging with iodine together was pioneered by Dr. Narsinga Rao in early 70s with all final inputs to design the formula and launch it by 1984. As a sequel to National Policy in the country, National Institute of Nutrition (NIN evolved the concept of double-fortified salt (DFS with iodine and iron for controlling the deficiencies of both these micro nutrients in a single measure as one intervention to control two micronutrient deficiencies. With lot of technical issues, bioavailabilty related issues it took a whale of time for its public utility level and took almost twenty years for localisation of the product into the market.The details of the product is provided in Table1

Comparative studies on two formulas of double fortified salt and it’s impact on anemia control

Directory of Open Access Journals (Sweden)

S Nair

2015-01-01

the issue in public health scenario.The vulnerable groups are the most affected ones. Even though the supplementation program is in place, compliance is not at its optimal levels. India already has an existing program on USI norms to supply iodized salt to all populations. Therefore, double fortification of salt with iron and iodine as a tool to combat these deficiencies was the best thought approach by various scientists. The efforts towards producing a stable formula containing iron merging with iodine together was pioneered by Dr. Narsinga Rao in early 70s with all final inputs to design the formula and launch it by 1984. As a sequel to National Policy in the country, National Institute of Nutrition (NIN evolved the concept of double-fortified salt (DFS with iodine and iron for controlling the deficiencies of both these micro nutrients in a single measure as one intervention to control two micronutrient deficiencies. With lot of technical issues, bioavailabilty related issues it took a whale of time for its public utility level and took almost twenty years for localisation of the product into the market.The details of the product is provided in Table1

Recurrent Pneumonia due to Double Aortic Arch

Directory of Open Access Journals (Sweden)

I. Sedighi

2012-04-01

Full Text Available Introduction: Pneumonia is one of the most common infections during childhood. In children with recurrent bacterial pneumonia complete evaluation for underlying factors is necessary. The most common underlying diseases include: antibody deficiencies , cystic fibrosis , tracheoesophageal fistula and increased pulmonary blood flow. Vascular ring and its pressure effect is a less common cause of stridor and recurrent pneumonia. Congenital abnormalities in aortic arch and main branches which form vascular ring around esophagus and trachea with variable pressure effect cause respiratory symptoms such as stridor , wheezing and recurrent pneumoniaCase Report: A 2 year old boy was admitted in our hospital with respiratory distress and cough . Chest x-Ray demonstrated right lobar pneumonia. He had history of stridor and wheezing from neonatal period and hospitalization due to pneumonia for four times. The patient received appropriate antibiotics. Despite fever and respiratory distress improvement, wheezing continued. Review of his medical documents showed fixed pressure effect on posterior aspect of esophagus in barium swallow. In CT angiography we confirmed double aortic arch.Conclusion: Double aortic arch is one of the causes of persistant respiratory symptom and recurrent pneumonia in children for which fluoroscopic barium swallow is the first non-invasive diagnostic method.(Sci J Hamadan Univ Med Sci 2012;19(1:70-74

Iron-Deficiency Anemia

Medline Plus

Full Text Available ... Are you curious about how inflammation from chronic diseases can cause iron-deficiency anemia? Read more When there is ... DBDR) is a leader in research on the causes, prevention, and treatment of blood diseases, including iron-deficiency anemia. Search the NIH Research ...

Iron deficiency anemia

Science.gov (United States)

Anemia - iron deficiency ... iron from old red blood cells. Iron deficiency anemia develops when your body's iron stores run low. ... You may have no symptoms if the anemia is mild. Most of the time, ... slowly. Symptoms may include: Feeling weak or tired more often ...

Does EEG-Neurofeedback Improve Neurocognitive Functioning in Children with Attention-Deficit/Hyperactivity Disorder? A Systematic Review and a Double-Blind Placebo-Controlled Study

Science.gov (United States)

Vollebregt, Madelon A.; van Dongen-Boomsma, Martine; Buitelaar, Jan K.; Slaats-Willemse, Dorine

2014-01-01

Background: The number of placebo-controlled randomized studies relating to EEG-neurofeedback and its effect on neurocognition in attention-deficient/hyperactivity disorder (ADHD) is limited. For this reason, a double blind, randomized, placebo-controlled study was designed to assess the effects of EEG-neurofeedback on neurocognitive functioning…

Review of Membrane Oxygen Enrichment for Efficient Combustion

Science.gov (United States)

Ariono, Danu; Kusuma Wardani, Anita

2017-07-01

Oxygen enrichment from air is a simple way of increasing the efficiency of combustion process, as in oxy-combustion. Oxy-combustion has become one of the most attracting combustion technologies because of its potential to address both pollutant reduction and CO2 capture. In oxy-combustion, the fuel and recycled flue gas are combusted with oxygen enriched air (OEA). By using OEA, many benefits can be obtained, such as increasing available heat, improving ignition characteristics, flue gas reduction, increasing productivity, energy efficiency, turndown ratio, and flame stability. Membrane-based gas separation for OEA production becomes an attractive technology over the conventional technology due to the some advantages, including low capital cost, low energy consumption, compact size, and modularity. A single pass through membrane usually can enrich O2 concentration in the air up to 35% and a 50% concentration can be achieved with a double pass of membrane. The use of OEA in the combustion process eliminates the presence of nitrogen in the flue gas. Hence, the flue gas is mainly composed of CO2 and condensable water that can be easily separated. This paper gives an overview of oxy-combustion with membrane technology for oxygen enrichment process. Special attention is given to OEA production and the effect of OEA to the efficiency of combustion.

Spin-dependent recombination involving oxygen-vacancy complexes in silicon

Science.gov (United States)

Franke, David P.; Hoehne, Felix; Vlasenko, Leonid S.; Itoh, Kohei M.; Brandt, Martin S.

2014-05-01

Spin-dependent relaxation and recombination processes in γ-irradiated n-type Czochralski-grown silicon are studied using continuous wave (cw) and pulsed electrically detected magnetic resonance (EDMR). Two processes involving the SL1 center, the neutral excited triplet state of the oxygen-vacancy complex, are observed which can be separated by their different dynamics. One of the processes is the relaxation of the excited SL1 state to the ground state of the oxygen-vacancy complex, the other a charge transfer between 31P donors and SL1 centers forming close pairs, as indicated by electrically detected electron double resonance. For both processes, the recombination dynamics is studied with pulsed EDMR techniques. We demonstrate the feasibility of true zero-field cw and pulsed EDMR for spin-1 systems and use this to measure the lifetimes of the different spin states of SL1 also at vanishing external magnetic field.

The physiological and biomechanical differences between double poling and G3 skating in world class cross-country skiers.

Science.gov (United States)

Sandbakk, Øyvind; Leirdal, Stig; Ettema, Gertjan

2015-03-01

The current study compared differences in cycle characteristics, energy expenditure and peak speed between double poling (DP) and G3 skating. Eight world class male sprint skiers performed a 5-min submaximal test at 16 km h(-1) and an incremental test to exhaustion at a 5% incline during treadmill roller skiing with two different techniques: DP where all propulsion comes from poling, and G3 skating where leg skating is added to each double poling movement. Video analyses determined cycle characteristics; respiratory parameters and blood lactate concentration determined the physiological responses. G3 skating resulted in 16% longer cycle lengths at 16% lower cycle rates, whereas oxygen uptake was independent of technique during submaximal roller skiing. The corresponding advantages for G3 skating during maximal roller skiing were reflected in 14% higher speed, 30% longer cycle length at 16% lower cycle rate and 11% higher peak oxygen uptake (all p skating. This was done by major increases in cycle lengths at slightly lower cycle rates and a higher aerobic energy delivery. However, the oxygen uptake for a given submaximal speed was not affected by technique although higher cycle rate was used in DP.

Effects of oxygen stoichiometry on the scaling behaviors of YBa2Cu3Ox grain boundary weak-links

International Nuclear Information System (INIS)

Wu, K.H.; Fu, C.M.; Jeng, W.J.

1994-01-01

The effects of oxygen stoichiometry on the transport properties of the pulsed laser deposited YBa 2 Cu 3 O x bicrystalline grain boundary weak-link junctions were studied. It is found that not only the cross boundary resistive transition foot structure can be manipulated repeatedly with oxygen annealling processes but the junction behaviors are also altered in accordance. In the fully oxygenated state i.e. with x=7.0 in YBa 2 Cu 3 O x stoichiometry, the junction critical current exhibits a power of 2 scaling behavior with temperature. In contrast, when annealed in the conditions of oxygen-deficient state (e.g. with x=6.9 in YBa 2 Cu 3 O x stoichiometry) the junction critical current switches to a linear temperature dependence behavior. The results are tentatively attributed to the modification of the structure in the boundary area upon oxygen annealing, which, in turn, will affect the effective dimension of the geometrically constrained weak-link bridges. The detailed discussion on the responsible physical mechanisms as well as the implications of the present results on device applications will be given

Oxygen effect on mutagenic ionizing radiation damage in Bacillus subtilis spores of DNA polymerase I-proficient and -deficient strains

International Nuclear Information System (INIS)

Tanooka, H.

1980-01-01

The nature of mutagenic ionizing radiation damage modified by the presence of oxygen or water was examined by comparing mutagenic with lethal expression of the damage in Bacillus subtilis spores irradiated with 6-MeV electrons. No specific difference was recognized between oxygen-dependent and -independent damages or between polA + -dependent and -independent damages with this system. The induced mutation frequency for His + mutation per lethal hit was 4.7 x 10 -5 for all tested cases

Interaction of nitroimidazole sensitizers and oxygen in the radiosensitization of mammalian cells at ultrahigh dose rates

International Nuclear Information System (INIS)

Michaels, H.B.; Ling, C.C.; Epp, E.R.; Peterson, E.C.

1981-01-01

When CHO cells, equilibrated with 0.44% oxygen, are irradiated with single 3-nsec pulses of electrons from a 600-kV-field emission source, a breaking survival curve is observed. The breaking behavior, believed to be the result of radiolytic oxygen depletion, can be prevented by the presence of a relatively low concentration of the hypoxic cell sensitizer misonidazole; similar results are obtained with metronidazole and Ro-05-9963. The resulting survival curves exhibit a sensitized response similar to that obtained with conventional dose rate radiation for CHO cells under this oxygen concentration. This degree of sensitization is greater than that observed for CHO cells irradiated at ultrahigh dose rates under the same concentration of sensitizer in nitrogen. The data suggest that the nitroimidazole compounds interfere with the radiation chemical oxygen depletion process and that the radiosensitization observed in the nonbreaking survival curve is the consequence of sensitization by both the nitroimidazole and, primarily, the oxygen rather than a direct subsitution for oxygen by the sensitizer. This conclusion is also supported by data obtained in double-pulse experiments. The results are discussed with regard to the mechanisms of the oxygen depletion process and radiosensitization

Direct observation of hopping induced spin polarization current in oxygen deficient Co-doped ZnO by Andreev reflection technique

Energy Technology Data Exchange (ETDEWEB)

Yang, Kung-Shang; Huang, Tzu-Yu; Dwivedi, G.D. [Department of Physics, National Sun Yat-sen University, Kaohsiung, Taiwan (China); Lin, Lu-Kuei; Lee, Shang-Fan [Taiwan Institute of Physics, Academia Sinica, Taipei, Taiwan (China); Sun, Shih-Jye [Department of Applied Physics, National Kaohsiung University, Kaohsiung, Taiwan (China); Chou, Hsiung, E-mail: hchou@mail.nsysu.edu.tw [Department of Physics, National Sun Yat-sen University, Kaohsiung, Taiwan (China)

2017-07-01

Highlights: • Co-doped ZnO thin-films were grown with varying V{sub O} concentartion. • PCAR measurements were done to study the SPC. • High spin polarization was observed above a certain V{sub O} concentartion. • High V{sub O} samples provide a high density of completed percolation path. • This complete percolation path gives rise to high SPC. - Abstract: Oxygen vacancy induced ferromagnetic coupling in diluted magnetic oxide (DMO) semiconductors have been reported in several studies, but technologically more crucial spin-polarized current (SPC) is still under-developed in DMOs. Few studies have claimed that VRH mechanism can originate the SPC, but, how VRH mechanism associated with percolation path, is not clearly understood. We used Point-contact Andreev reflection (PCAR) technique to probe the SPC in Co-doped ZnO (CZO) films. Since the high resistance samples cause broadening in conductance(G)-voltage(V) curves, which may result in an unreliable evaluation of spin polarization, we include two extra parameters, (i) effective temperature and (ii) spreading resistance, for the simulation to avoid the uncertainty in extracting spin polarization. The effective G-V curves and higher spin polarization can be obtained above a certain oxygen vacancy concentration. The number of completed and fragmentary percolation paths is proportional to the concentration of oxygen vacancies. For low oxygen vacancy samples, the Pb-tip has a higher probability of covering fragmentary percolation paths than the complete ones, due to its small contact size. The completed paths may remain independent of one another and get polarized in different directions, resulting in lower spin-polarization value. High oxygen vacancy samples provide a high density of completed path, most of them link to one another by crossing over, and gives rise to high spin-polarization value.

Benefits of supplemental oxygen in exercise training in nonhypoxemic chronic obstructive pulmonary disease patients.

Science.gov (United States)

Emtner, Margareta; Porszasz, Janos; Burns, Mary; Somfay, Attila; Casaburi, Richard

2003-11-01

Supplemental oxygen improves exercise tolerance of normoxemic and hypoxemic chronic obstructive pulmonary disease (COPD) patients. We determined whether nonhypoxemic COPD patients undergoing exercise training while breathing supplemental oxygen achieve higher intensity and therefore improve exercise capacity more than patients breathing air. A double-blinded trial was performed involving 29 nonhypoxemic patients (67 years, exercise SaO2 > 88%) with COPD (FEV1 = 36% predicted). All exercised on cycle ergometers for 45 minutes, 3 times per week for 7 weeks at high-intensity targets. During exercise, they received oxygen (3 L/minute) (n = 14) or compressed air (3 L/minute) (n = 15). Both groups had a higher exercise tolerance after training and when breathing oxygen. However, the oxygen-trained group increased the training work rate more rapidly than the air-trained group. The mean +/- SD work rate during the last week was 62 +/- 19 W (oxygen-trained group) and 52 +/- 22 W (air-trained group) (p work rate tests increased more in the oxygen-trained group (14.5 minutes) than in the air-trained group (10.5 minutes) (p < 0.05). At isotime, the breathing rate decreased four breaths per minute in the oxygen-trained group and one breath per minute in the air-trained group (p = 0.001). We conclude that supplemental oxygen provided during high-intensity training yields higher training intensity and evidence of gains in exercise tolerance in laboratory testing.

Molecular and biochemical mechanisms in teratogenesis involving reactive oxygen species

International Nuclear Information System (INIS)

Wells, Peter G.; Bhuller, Yadvinder; Chen, Connie S.; Jeng, Winnie; Kasapinovic, Sonja; Kennedy, Julia C.; Kim, Perry M.; Laposa, Rebecca R.; McCallum, Gordon P.; Nicol, Christopher J.; Parman, Toufan; Wiley, Michael J.; Wong, Andrea W.

2005-01-01

Developmental pathologies may result from endogenous or xenobiotic-enhanced formation of reactive oxygen species (ROS), which oxidatively damage cellular macromolecules and/or alter signal transduction. This minireview focuses upon several model drugs (phenytoin, thalidomide, methamphetamine), environmental chemicals (benzo[a]pyrene) and gamma irradiation to examine this hypothesis in vivo and in embryo culture using mouse, rat and rabbit models. Embryonic prostaglandin H synthases (PHSs) and lipoxygenases bioactivate xenobiotics to free radical intermediates that initiate ROS formation, resulting in oxidation of proteins, lipids and DNA. Oxidative DNA damage and embryopathies are reduced in PHS knockout mice, and in mice treated with PHS inhibitors, antioxidative enzymes, antioxidants and free radical trapping agents. Thalidomide causes embryonic DNA oxidation in susceptible (rabbit) but not resistant (mouse) species. Embryopathies are increased in mutant mice deficient in the antioxidative enzyme glucose-6-phosphate dehydrogenase (G6PD), or by glutathione (GSH) depletion, or inhibition of GSH peroxidase or GSH reductase. Inducible nitric oxide synthase knockout mice are partially protected. Inhibition of Ras or NF-kB pathways reduces embryopathies, implicating ROS-mediated signal transduction. Atm and p53 knockout mice deficient in DNA damage response/repair are more susceptible to xenobiotic or radiation embryopathies, suggesting a teratological role for DNA damage, consistent with enhanced susceptibility to methamphetamine in ogg1 knockout mice with deficient repair of oxidative DNA damage. Even endogenous embryonic oxidative stress carries a risk, since untreated G6PD- or ATM-deficient mice have increased embryopathies. Thus, embryonic processes regulating the balance of ROS formation, oxidative DNA damage and repair, and ROS-mediated signal transduction may be important determinants of teratological risk

Metallothionein deficiency aggravates depleted uranium-induced nephrotoxicity

Energy Technology Data Exchange (ETDEWEB)

Hao, Yuhui; Huang, Jiawei; Gu, Ying; Liu, Cong; Li, Hong; Liu, Jing; Ren, Jiong; Yang, Zhangyou [State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Combined Injury, Chongqing Engineering Research Center for Nanomedicine, College of Preventive Medicine, Third Military Medical University, No. 30 Gaotanyan Street, Shapingba District, Chongqing 400038 (China); Peng, Shuangqing [Evaluation and Research Center for Toxicology, Institute of Disease Control and Prevention, Academy of Military Medical Science, 20 Dongdajie Street, Fengtai District, Beijing 100071 (China); Wang, Weidong, E-mail: wwdwyl@sina.com [Department of Radiation Oncology, Shanghai Jiao Tong University Affiliated Sixth People' s Hospital, Shanghai 200233 (China); Li, Rong, E-mail: yuhui_hao@126.com [State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Combined Injury, Chongqing Engineering Research Center for Nanomedicine, College of Preventive Medicine, Third Military Medical University, No. 30 Gaotanyan Street, Shapingba District, Chongqing 400038 (China)

2015-09-15

Depleted uranium (DU) has been widely used in both civilian and military activities, and the kidney is the main target organ of DU during acute high-dose exposures. In this study, the nephrotoxicity caused by DU in metallothionein-1/2-null mice (MT −/−) and corresponding wild-type (MT +/+) mice was investigated to determine any associations with MT. Each MT −/− or MT +/+ mouse was pretreated with a single dose of DU (10 mg/kg, intraperitoneal injection) or an equivalent volume of saline. After 4 days of DU administration, kidney changes were assessed. After DU exposure, serum creatinine and serum urea nitrogen in MT −/− mice significantly increased than in MT +/+ mice, with more severe kidney pathological damage. Moreover, catalase and superoxide dismutase (SOD) decreased, and generation of reactive oxygen species and malondialdehyde increased in MT −/− mice. The apoptosis rate in MT −/− mice significantly increased, with a significant increase in both Bax and caspase 3 and a decrease in Bcl-2. Furthermore, sodium-glucose cotransporter (SGLT) and sodium-phosphate cotransporter (NaPi-II) were significantly reduced after DU exposure, and the change of SGLT was more evident in MT −/− mice. Finally, exogenous MT was used to evaluate the correlation between kidney changes induced by DU and MT doses in MT −/− mice. The results showed that, the pathological damage and cell apoptosis decreased, and SOD and SGLT levels increased with increasing dose of MT. In conclusion, MT deficiency aggravated DU-induced nephrotoxicity, and the molecular mechanisms appeared to be related to the increased oxidative stress and apoptosis, and decreased SGLT expression. - Highlights: • MT −/− and MT +/+ mice were used to evaluate nephrotoxicity of DU. • Renal damage was more evident in the MT −/− mice after exposure to DU. • Exogenous MT also protects against DU-induced nephrotoxicity. • MT deficiency induced more ROS and apoptosis after exposure to

Metallothionein deficiency aggravates depleted uranium-induced nephrotoxicity

International Nuclear Information System (INIS)

Hao, Yuhui; Huang, Jiawei; Gu, Ying; Liu, Cong; Li, Hong; Liu, Jing; Ren, Jiong; Yang, Zhangyou; Peng, Shuangqing; Wang, Weidong; Li, Rong

2015-01-01

Depleted uranium (DU) has been widely used in both civilian and military activities, and the kidney is the main target organ of DU during acute high-dose exposures. In this study, the nephrotoxicity caused by DU in metallothionein-1/2-null mice (MT −/−) and corresponding wild-type (MT +/+) mice was investigated to determine any associations with MT. Each MT −/− or MT +/+ mouse was pretreated with a single dose of DU (10 mg/kg, intraperitoneal injection) or an equivalent volume of saline. After 4 days of DU administration, kidney changes were assessed. After DU exposure, serum creatinine and serum urea nitrogen in MT −/− mice significantly increased than in MT +/+ mice, with more severe kidney pathological damage. Moreover, catalase and superoxide dismutase (SOD) decreased, and generation of reactive oxygen species and malondialdehyde increased in MT −/− mice. The apoptosis rate in MT −/− mice significantly increased, with a significant increase in both Bax and caspase 3 and a decrease in Bcl-2. Furthermore, sodium-glucose cotransporter (SGLT) and sodium-phosphate cotransporter (NaPi-II) were significantly reduced after DU exposure, and the change of SGLT was more evident in MT −/− mice. Finally, exogenous MT was used to evaluate the correlation between kidney changes induced by DU and MT doses in MT −/− mice. The results showed that, the pathological damage and cell apoptosis decreased, and SOD and SGLT levels increased with increasing dose of MT. In conclusion, MT deficiency aggravated DU-induced nephrotoxicity, and the molecular mechanisms appeared to be related to the increased oxidative stress and apoptosis, and decreased SGLT expression. - Highlights: • MT −/− and MT +/+ mice were used to evaluate nephrotoxicity of DU. • Renal damage was more evident in the MT −/− mice after exposure to DU. • Exogenous MT also protects against DU-induced nephrotoxicity. • MT deficiency induced more ROS and apoptosis after exposure to

Folate deficiency facilitates recruitment of upstream binding factor to hot spots of DNA double-strand breaks of rRNA genes and promotes its transcription.

Science.gov (United States)

Xie, Qiu; Li, Caihua; Song, Xiaozhen; Wu, Lihua; Jiang, Qian; Qiu, Zhiyong; Cao, Haiyan; Yu, Kaihui; Wan, Chunlei; Li, Jianting; Yang, Feng; Huang, Zebing; Niu, Bo; Jiang, Zhengwen; Zhang, Ting

2017-03-17

The biogenesis of ribosomes in vivo is an essential process for cellular functions. Transcription of ribosomal RNA (rRNA) genes is the rate-limiting step in ribosome biogenesis controlled by environmental conditions. Here, we investigated the role of folate antagonist on changes of DNA double-strand breaks (DSBs) landscape in mouse embryonic stem cells. A significant DSB enhancement was detected in the genome of these cells and a large majority of these DSBs were found in rRNA genes. Furthermore, spontaneous DSBs in cells under folate deficiency conditions were located exclusively within the rRNA gene units, representing a H3K4me1 hallmark. Enrichment H3K4me1 at the hot spots of DSB regions enhanced the recruitment of upstream binding factor (UBF) to rRNA genes, resulting in the increment of rRNA genes transcription. Supplement of folate resulted in a restored UBF binding across DNA breakage sites of rRNA genes, and normal rRNA gene transcription. In samples from neural tube defects (NTDs) with low folate level, up-regulation of rRNA gene transcription was observed, along with aberrant UBF level. Our results present a new view by which alterations in folate levels affects DNA breakage through epigenetic control leading to the regulation of rRNA gene transcription during the early stage of development. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Singlet oxygen quenching by oxygen in tetraphenyl-porphyrin solutions

International Nuclear Information System (INIS)

Dedic, Roman; Korinek, Miloslav; Molnar, Alexander; Svoboda, Antonin; Hala, Jan

2006-01-01

Time-resolved measurement of singlet oxygen infrared phosphorescence is a powerful tool for determination of quantum yields and kinetics of its photosensitization. This technique was employed to investigate in detail the previously observed effect of singlet oxygen quenching by oxygen. The question whether the singlet oxygen is quenched by oxygen in ground or in excited state was addressed by study of two complementary dependencies of singlet oxygen lifetimes: on dissolved oxygen concentration and on excitation intensity. Oxygen concentration dependence study of meso-tetra(4-sulphonato)phenylporphyrin (TPPS 4 ) phosphorescence kinetics showed linearity of the dependence of TPPS 4 triplet state rate-constant. Corresponding bimolecular quenching constant of (1.5±0.1)x10 9 l/mol s was obtained. On the other hand, rate constants of singlet oxygen depopulation exhibit nonlinear dependence on oxygen concentration. Comparison of zero oxygen concentration-extrapolated value of singlet oxygen lifetime of (6.5±0.4) μs to (3.7±0.1) μs observed under air-saturated conditions indicates importance of the effect of quenching of singlet oxygen by oxygen. Upward-sloping dependencies of singlet oxygen depopulation rate-constant on excitation intensity evidence that singlet oxygen is predominantly quenched by oxygen in excited singlet state

Supplemental Oxygen During High-Intensity Exercise Training in Nonhypoxemic Chronic Obstructive Pulmonary Disease.

Science.gov (United States)

Neunhäuserer, Daniel; Steidle-Kloc, Eva; Weiss, Gertraud; Kaiser, Bernhard; Niederseer, David; Hartl, Sylvia; Tschentscher, Marcus; Egger, Andreas; Schönfelder, Martin; Lamprecht, Bernd; Studnicka, Michael; Niebauer, Josef

2016-11-01

Physical exercise training is an evidence-based treatment in chronic obstructive pulmonary disease, and patients' peak work rate is associated with reduced chronic obstructive pulmonary disease mortality. We assessed whether supplemental oxygen during exercise training in nonhypoxemic patients with chronic obstructive pulmonary disease might lead to superior training outcomes, including improved peak work rate. This was a randomized, double-blind, controlled, crossover trial. Twenty-nine patients with chronic obstructive pulmonary disease (aged 63.5 ± 5.9 years; forced expiratory volume in 1 second percent predicted, 46.4 ± 8.6) completed 2 consecutive 6-week periods of endurance and strength training with progressive intensity, which was performed 3 times per week with supplemental oxygen or compressed medical air (flow via nasal cannula: 10 L/min). Each session of electrocardiography-controlled interval cycling lasted 31 minutes and consisted of a warm-up, 7 cycles of 1-minute intervals at 70% to 80% of peak work rate alternating with 2 minutes of active recovery, and final cooldown. Thereafter, patients completed 8 strength-training exercises of 1 set each with 8 to 15 repetitions to failure. Change in peak work rate was the primary study end point. The increase in peak work rate was more than twice as high when patients exercised with supplemental oxygen compared with medical air (0.16 ± 0.02 W/kg vs 0.07 ± 0.02 W/kg; P work rate was 39.1% of the overall training effect, whereas it had no influence on strength gain (P > .1 for all exercises). We report that supplemental oxygen in nonhypoxemic chronic obstructive pulmonary disease doubled the effect of endurance training but had no effect on strength gain. Copyright © 2016 Elsevier Inc. All rights reserved.

Observation of the strain-driven charge-ordered state in La sub 0 sub . sub 7 sub C a sub 0 sub . sub 3 MnO sub 3 sub - sub d elta thin film with oxygen deficiency

CERN Document Server

Prokhorov, V G; Kaminsky, G G; Svetchnikov, V L; Zandbergen, H W; Lee, Y P; Park, J S; Kim, K W

2003-01-01

The magnetic and transport properties of La sub 0 sub . sub 7 Ca sub 0 sub . sub 3 MnO sub 3 sub - sub d elta films with an oxygen deficiency (delta approx 0.1) and a La sub 0 sub . sub 9 Ca sub 0 sub . sub 1 MnO sub 3 film with the stoichiometric oxygen content are investigated in a wide temperature range. It is shown that the charge-ordered insulating (COI) state is observed for a La sub 0 sub . sub 7 Ca sub 0 sub . sub 3 MnO sub 2 sub . sub 9 film with thickness d <= 30 nm, which manifests mainly a cubic crystal structure with an anomalously small lattice parameter for this composition. An increase in the film thickness (d approx 60 nm) leads to a structural transition from the lattice-strained cubic to the relaxed rhombohedral phase, is accompanied by a shift of the Curie point (T sub C) to lower temperature and a frustration of the COI state. The magnetic and transport properties of the La sub 0 sub . sub 7 Ca sub 0 sub . sub 3 MnO sub 2 sub . sub 9 film with d approx 60 nm are similar to those exhibi...

Magnetoresistance Versus Oxygen Deficiency in Epi-stabilized SrRu1 - x Fe x O3 - δ Thin Films.

Science.gov (United States)

Dash, Umasankar; Acharya, Susant Kumar; Lee, Bo Wha; Jung, Chang Uk

2017-12-01

Oxygen vacancies have a profound effect on the magnetic, electronic, and transport properties of transition metal oxide materials. Here, we studied the influence of oxygen vacancies on the magnetoresistance (MR) properties of SrRu 1 - x Fe x O 3 - δ epitaxial thin films (x = 0.10, 0.20, and 0.30). For this purpose, we synthesized highly strained epitaxial SrRu 1 - x Fe x O 3 - δ thin films with atomically flat surfaces containing different amounts of oxygen vacancies using pulsed laser deposition. Without an applied magnetic field, the films with x = 0.10 and 0.20 showed a metal-insulator transition, while the x = 0.30 thin film showed insulating behavior over the entire temperature range of 2-300 K. Both Fe doping and the concentration of oxygen vacancies had large effects on the negative MR contributions. For the low Fe doping case of x = 0.10, in which both films exhibited metallic behavior, MR was more prominent in the film with fewer oxygen vacancies or equivalently a more metallic film. For semiconducting films, higher MR was observed for more semiconducting films having more oxygen vacancies. A relatively large negative MR (~36.4%) was observed for the x = 0.30 thin film with a high concentration of oxygen vacancies (δ = 0.12). The obtained results were compared with MR studies for a polycrystal of (Sr 1 - x La x )(Ru 1 - x Fe x )O 3 . These results highlight the crucial role of oxygen stoichiometry in determining the magneto-transport properties in SrRu 1 - x Fe x O 3 - δ thin films.

Phenotyping of Nod1/2 double deficient mice and characterization of Nod1/2 in systemic inflammation and associated renal disease

Directory of Open Access Journals (Sweden)

Ingrid Stroo

2012-10-01

It is indispensable to thoroughly characterize each animal model in order to distinguish between primary and secondary effects of genetic changes. The present study analyzed Nod1 and Nod2 double deficient (Nod1/2 DKO mice under physiological and inflammatory conditions. Nod1 and Nod2 are members of the Nucleotide-binding domain and Leucine-rich repeat containing Receptor (NLR family. Several inflammatory disorders, such as Crohn's disease and asthma, are linked to genetic changes in either Nod1 or Nod2. These associations suggest that Nod1 and Nod2 play important roles in regulating the immune system. Three-month-old wildtype (Wt and Nod1/2 DKO mice were sacrificed, body and organ weight were determined, and blood was drawn. Except for lower liver weight in Nod1/2 DKO mice, no differences were found in body/organ weight between both strains. Leukocyte count and composition was comparable. No significant changes in analyzed plasma biochemical markers were found. Additionally, intestinal and vascular permeability was determined. Nod1/2 DKO mice show increased susceptibility for intestinal permeability while vascular permeability was not affected. Next we induced septic shock and organ damage by administering LPS+PGN intraperitoneally to Wt and Nod1/2 DKO mice and sacrificed animals after 2 and 24 hours. The systemic inflammatory and metabolic response was comparable between both strains. However, renal response was different as indicated by partly preserved kidney function and tubular epithelial cell damage in Nod1/2 DKO at 24 hours. Remarkably, renal inflammatory mediators Tnfα, KC and Il-10 were significantly increased in Nod1/2 DKO compared with Wt mice at 2 hours. Systematic analysis of Nod1/2 DKO mice revealed a possible role of Nod1/2 in the development of renal disease during systemic inflammation.

An Assessment of the Selenium Status of Iodine-Deficient and Non-Iodine Deficient Filipino Children

Directory of Open Access Journals (Sweden)

Ma. Sofia Amarra

2002-06-01

Full Text Available The aim of this study is to examine and compare blood selenium levels in iodine-deficient and non-iodine deficient children. Two groups of children were examined: one group with iodine deficiency (n=31 and the other group with normal iodine status (n=32. Blood was extracted by venipuncture from children aged 6-10 years attending first grade in Commonwealth Elementary School in Quezon City. Whole blood selenium was examined by electrothermal atomic absorption spectrophotometry (AAS. Iodine status was determined by goiter palpation and urinary iodine excretion. Mean selenium levels of deficient and non-deficient children were compared using T-test. Using a cut-off value of 60 mg Se/L whole blood, the proportion of children with normal and deficient iodine status who fell below this cut-off was compared using chi-square test. Whole blood selenium values ranged from 17.6 to 133.6 mg/L. There were no significant differences in mean selenium levels between children with normal and deficient iodine status. Children with normal iodine status had a mean blood selenium level of 55.87 ± 26.3 mg/L while children with deficient iodine status had a mean level of 58.76 ± 26.4 mg/L. Sixty percent of children had blood selenium levels below the arbitrary cut-off of 60 mg/L with no significant difference between groups (p = 0.165, indicating that selenium deficiency is prevalent in this group of children regardless of iodine status. Since selenium deficiency limits the response to iodine supplementation, further investigation is needed to determine whether the same situation exists in children from other areas.

Deoxyribonucleic acid repair in Escherichia coli mutants deficient in the 5'----3' exonuclease activity of deoxyribonucleic acid polymerase I and exonuclease VII

International Nuclear Information System (INIS)

Chase, J.W.; Masker, W.E.

1977-01-01

A series of Escherichia coli strains deficient in the 5'----3' exonuclease activity associated with deoxyribonucleic acid (DNA) polymerase I (exonuclease VI) and exonuclease VII has been constructed. Both of these enzymes are capable of pyrimidine dimer excision in vitro. These strains were examined for conditional lethality, sensitivity to ultraviolet (UV) and X-irradiation, postirradiation DNA degradation, and ability to excise pyrimidine dimers. It was found that strains deficient in both exonuclease VI (polAex-) and exonuclease VII (xseA-) are significantly reduced in their ability to survive incubation at elevated temperature (43 degrees C) beyond the reduction previously observed for the polAex single mutants. The UV and X-ray sensitivity of the exonuclease VI-deficient strains was not increased by the addition of the xseA7 mutation. Mutants deficient in both enzymes are about as efficient as wild-type strains at excising dimers produced by up to 40 J/m2 UV. At higher doses strains containing only polAex- mutations show reduced ability to excise dimers; however, the interpretation of dimer excision data at these doses is complicated by extreme postirradiation DNA degradation in these strains. The additional deficiency in the polAex xseA7 double-mutant strains has no significant effect on either postirradiation DNA degradation or the apparent deficiency in dimer excision at high UV doses observed in polAex single mutants

[Iron deficiency and pica].

Science.gov (United States)

Muñoz, J A; Marcos, J; Risueño, C E; de Cos, C; López, R; Capote, F J; Martín, M V; Gil, J L

1998-02-01

To study the relationship between pica and iron-lack anaemia in a series of iron-deficiency patients in order to establish the pathogenesis of such relationship. Four-hundred and thirty-three patients were analysed. Pica was studied by introducing certain diet queries into the clinical history. All patients received oral iron and were periodically controlled with the usual clinico-haematological procedures. Pica was present in 23 patients (5.3%). Eight nourishing (namely, coffee grains, almonds, chocolate, ice, lettuce, carrots, sunflower seeds and bread) and 2 non-nourishing (clay and paper) substances were involved. A second episode of pica appeared in 9 cases upon relapsing of iron deficiency. Both anaemia and pica were cured by etiologic and substitutive therapy in all instances. No clear correlation was found with either socio-economic status or pathogenetic causes of iron deficiency and pica, and no haematological differences were seen between patients with pica and those without this alteration. (1) The pathogenesis of pica is unclear, although it appears unrelated to the degree of iron deficiency. (2) According to the findings in this series, pica seems a consequence of iron deficiency rather than its cause. (3) Adequate therapy can cure both conditions, although pica may reappear upon relapse of iron deficiency.

Iron-Deficiency Anemia

Medline Plus

Full Text Available ... Topics section only, or the News and Resources section. NHLBI Entire Site NHLBI Entire Site Health ... español Iron-deficiency anemia is a common type of anemia that occurs if you do not have enough iron in your body. People with mild or moderate iron-deficiency anemia ...

Iron-Deficiency Anemia

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Full Text Available ... also are hoping to determine which iron supplements work best to treat iron-deficiency anemia in children who do not consume the daily recommended amount of iron. Read less Participate in NHLBI Clinical Trials We lead or sponsor many studies related to iron-deficiency anemia. See if you ...

Use of orthogonal field alternational gel electrophoresis (OFAGE) for studying DNA double strand breakage and repair

International Nuclear Information System (INIS)

Contopoulou, C.R.; Cook, V.; Mortimer, R.K.

1987-01-01

The study of DNA double strand breakage and repair has normally been carried by using neutral sucrose gradient or neutral elution techniques. The authors have applied OFAGE procedures to study x-ray induced double strand breaks and repair. Breakage of chromosomes is seen by a decrease in intensity of individual chromosome bands; as expected, this decrease becomes more pronounced as chromosome size increases. The fragments of broken chromosomes appears as a broad smear in the size range 100 kb to 1000 kb. Following repair, these fragments partially disappear and the chromosomal bands increase in intensity. In four repair deficient mutants, rad51, rad52, rad54, rad55, no increase in chromosomal band intensity was seen. These results have been confirmed by blotting for a specific chromosome

AMP Deaminase 3 Deficiency Enhanced 5′-AMP Induction of Hypometabolism

Science.gov (United States)

Daniels, Isadora Susan; O′Brien, William G.; Nath, Vinay; Zhao, Zhaoyang; Lee, Cheng Chi

2013-01-01

A hypometabolic state can be induced in mice by 5′-AMP administration. Previously we proposed that an underlying mechanism for this hypometabolism is linked to reduced erythrocyte oxygen transport function due to 5′-AMP uptake altering the cellular adenylate equilibrium. To test this hypothesis, we generated mice deficient in adenosine monophosphate deaminase 3 (AMPD3), the key catabolic enzyme for 5′-AMP in erythrocytes. Mice deficient in AMPD3 maintained AMPD activities in all tissues except erythrocytes. Developmentally and morphologically, the Ampd3−/− mice were indistinguishable from their wild type siblings. The levels of ATP, ADP but not 5′-AMP in erythrocytes of Ampd3−/− mice were significantly elevated. Fasting blood glucose levels of the Ampd3−/− mice were comparable to wild type siblings. In comparison to wild type mice, the Ampd3−/− mice displayed a deeper hypometabolism with a significantly delayed average arousal time in response to 5′-AMP administration. Together, these findings demonstrate a central role of AMPD3 in the regulation of 5′-AMP mediated hypometabolism and further implicate erythrocytes in this behavioral response. PMID:24066180

Biodegradation of the herbicide Diuron in a packed bed channel and a double biobarrier with distribution of oxygenated liquid by airlift devices: influence of oxygen limitation.

Science.gov (United States)

Castañón-González, J Humberto; Galíndez-Mayer, Juvencio; Ruiz-Ordaz, Nora; Rocha-Martínez, Lizeth; Peña-Partida, José Carlos; Marrón-Montiel, Erick; Santoyo-Tepole, Fortunata

2016-01-25

From agricultural soils, where the herbicide Diuron has been frequently applied, a microbial community capable of degrading Diuron and 3,4-dichloroaniline was obtained. The volumetric rates and degradation efficiencies of Diuron and 3,4-DCA were evaluated in two distinct biofilm reactors, which differ in their operating conditions. One is a horizontal fixed bed reactor; plug-flow operated (PF-PBC) with severe limitation of oxygen. In this reactor, the air was supplied to an equalizer reservoir at the start of the PF-PBC reactor. The other is a compartmentalized aerobic biobarrier with internal recirculation of liquid aerated through airlift devices (ALB), continuously or intermittently operated. Both reactors were inoculated with a microbial community capable of degrading Diuron, isolated from a sugarcane field. In the oxygen-limited PF-PBC reactor, 3,4-DCA accumulation was detected, mainly in the middle zone of the packed channel. On the contrary, in the fully aerobic ALB reactor, minimal accumulation of catabolic byproducts was detected, and high Diuron removal efficiencies and removal rates were obtained when it was continuously operated in steady-state conditions. Additionally, the influence of oxygen limitation on the kinetic behavior of the PF-PBC reactor was determined, and a method to estimate the local removal rates of Diuron RV,CD along the plug-flow channel is described. It was observed that the local values of the instantaneous removal rate of Diuron dCD/dt are high in the aerobic region of the PF-PBC reactor; but, suddenly decay in the reactor zones limited by dissolved oxygen. Copyright © 2015 Elsevier B.V. All rights reserved.

Mycobacterial nonhomologous end joining mediates mutagenic repair of chromosomal double-strand DNA breaks.

Science.gov (United States)

Stephanou, Nicolas C; Gao, Feng; Bongiorno, Paola; Ehrt, Sabine; Schnappinger, Dirk; Shuman, Stewart; Glickman, Michael S

2007-07-01

Bacterial nonhomologous end joining (NHEJ) is a recently described DNA repair pathway best characterized in mycobacteria. Bacterial NHEJ proteins LigD and Ku have been analyzed biochemically, and their roles in linear plasmid repair in vivo have been verified genetically; yet the contributions of NHEJ to repair of chromosomal DNA damage are unknown. Here we use an extensive set of NHEJ- and homologous recombination (HR)-deficient Mycobacterium smegmatis strains to probe the importance of HR and NHEJ in repairing diverse types of chromosomal DNA damage. An M. smegmatis Delta recA Delta ku double mutant has no apparent growth defect in vitro. Loss of the NHEJ components Ku and LigD had no effect on sensitivity to UV radiation, methyl methanesulfonate, or quinolone antibiotics. NHEJ deficiency had no effect on sensitivity to ionizing radiation in logarithmic- or early-stationary-phase cells but was required for ionizing radiation resistance in late stationary phase in 7H9 but not LB medium. In addition, NHEJ components were required for repair of I-SceI mediated chromosomal double-strand breaks (DSBs), and in the absence of HR, the NHEJ pathway rapidly mutates the chromosomal break site. The molecular outcomes of NHEJ-mediated chromosomal DSB repair involve predominantly single-nucleotide insertions at the break site, similar to previous findings using plasmid substrates. These findings demonstrate that prokaryotic NHEJ is specifically required for DSB repair in late stationary phase and can mediate mutagenic repair of homing endonuclease-generated chromosomal DSBs.

Oxygen vacancy doping of hematite analyzed by electrical conductivity and thermoelectric power measurements

Science.gov (United States)

Mock, Jan; Klingebiel, Benjamin; Köhler, Florian; Nuys, Maurice; Flohre, Jan; Muthmann, Stefan; Kirchartz, Thomas; Carius, Reinhard

2017-11-01

Hematite (α -F e2O3 ) is known for poor electronic transport properties, which are the main drawback of this material for optoelectronic applications. In this study, we investigate the concept of enhancing electrical conductivity by the introduction of oxygen vacancies during temperature treatment under low oxygen partial pressure. We demonstrate the possibility of tuning the conductivity continuously by more than five orders of magnitude during stepwise annealing in a moderate temperature range between 300 and 620 K. With thermoelectric power measurements, we are able to attribute the improvement of the electrical conductivity to an enhanced charge-carrier density by more than three orders of magnitude. We compare the oxygen vacancy doping of hematite thin films with hematite nanoparticle layers. Thereby we show that the dominant potential barrier that limits charge transport is either due to grain boundaries in hematite thin films or due to potential barriers that occur at the contact area between the nanoparticles, rather than the potential barrier within the small polaron hopping model, which is usually applied for hematite. Furthermore, we discuss the transition from oxygen-deficient hematite α -F e2O3 -x towards the magnetite F e3O4 phase of iron oxide at high density of vacancies.

Double-Skinned Forward Osmosis Membranes for Reducing Internal Concentration Polarization within the Porous Sublayer

KAUST Repository

Wang, Kai Yu

2010-05-19

A scheme to fabricate forward osmosis membranes comprising a highly porous sublayer sandwiched between two selective skin layers via phase inversion was proposed. One severe deficiency of existing composite and asymmetric membranes used in forward osmosis is the presence of unfavorable internal concentration polarization within the porous support layer that hinders both (i) separation (salt flux) and (ii) the performance (water flux). The double skin layers of the tailored membrane may mitigate the internal concentration polarization by preventing the salt and other solutes in the draw solution from penetrating into the membrane porous support. The prototype double-skinned cellulose acetate membrane displayed a water flux of 48.2 L·m-2·h -1 and lower reverse salt transport of 6.5 g·m -2·h-1 using 5.0 M MgCl2 as the draw solution in a forward osmosis process performed at 22 °C. This can be attributed to the effective salt rejection by the double skin layers and the low water transport resistance within the porous support layer. The prospects of utilizing the double-selective layer membranes may have potential application in forward osmosis for desalination. This study may help pave the way to improve the membrane design for the forward osmosis process. © 2010 American Chemical Society.

Double-Skinned Forward Osmosis Membranes for Reducing Internal Concentration Polarization within the Porous Sublayer

KAUST Repository

Wang, Kai Yu; Ong, Rui Chin; Chung, Tai-Shung

2010-01-01

A scheme to fabricate forward osmosis membranes comprising a highly porous sublayer sandwiched between two selective skin layers via phase inversion was proposed. One severe deficiency of existing composite and asymmetric membranes used in forward osmosis is the presence of unfavorable internal concentration polarization within the porous support layer that hinders both (i) separation (salt flux) and (ii) the performance (water flux). The double skin layers of the tailored membrane may mitigate the internal concentration polarization by preventing the salt and other solutes in the draw solution from penetrating into the membrane porous support. The prototype double-skinned cellulose acetate membrane displayed a water flux of 48.2 L·m-2·h -1 and lower reverse salt transport of 6.5 g·m -2·h-1 using 5.0 M MgCl2 as the draw solution in a forward osmosis process performed at 22 °C. This can be attributed to the effective salt rejection by the double skin layers and the low water transport resistance within the porous support layer. The prospects of utilizing the double-selective layer membranes may have potential application in forward osmosis for desalination. This study may help pave the way to improve the membrane design for the forward osmosis process. © 2010 American Chemical Society.

Ischaemic strokes in patients with pulmonary arteriovenous malformations and hereditary hemorrhagic telangiectasia: associations with iron deficiency and platelets.

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Claire L Shovlin

Full Text Available BACKGROUND: Pulmonary first pass filtration of particles marginally exceeding ∼7 µm (the size of a red blood cell is used routinely in diagnostics, and allows cellular aggregates forming or entering the circulation in the preceding cardiac cycle to lodge safely in pulmonary capillaries/arterioles. Pulmonary arteriovenous malformations compromise capillary bed filtration, and are commonly associated with ischaemic stroke. Cohorts with CT-scan evident malformations associated with the highest contrast echocardiographic shunt grades are known to be at higher stroke risk. Our goal was to identify within this broad grouping, which patients were at higher risk of stroke. METHODOLOGY: 497 consecutive patients with CT-proven pulmonary arteriovenous malformations due to hereditary haemorrhagic telangiectasia were studied. Relationships with radiologically-confirmed clinical ischaemic stroke were examined using logistic regression, receiver operating characteristic analyses, and platelet studies. PRINCIPAL FINDINGS: Sixty-one individuals (12.3% had acute, non-iatrogenic ischaemic clinical strokes at a median age of 52 (IQR 41-63 years. In crude and age-adjusted logistic regression, stroke risk was associated not with venous thromboemboli or conventional neurovascular risk factors, but with low serum iron (adjusted odds ratio 0.96 [95% confidence intervals 0.92, 1.00], and more weakly with low oxygen saturations reflecting a larger right-to-left shunt (adjusted OR 0.96 [0.92, 1.01]. For the same pulmonary arteriovenous malformations, the stroke risk would approximately double with serum iron 6 µmol/L compared to mid-normal range (7-27 µmol/L. Platelet studies confirmed overlooked data that iron deficiency is associated with exuberant platelet aggregation to serotonin (5HT, correcting following iron treatment. By MANOVA, adjusting for participant and 5HT, iron or ferritin explained 14% of the variance in log-transformed aggregation-rate (p = 0

Diagnóstico diferencial da deficiência de ferro Differential diagnosis of iron deficiency

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Perla Vicari

2010-06-01

Full Text Available A deficiência de ferro é considerada a patologia hematológica mais prevalente no homem. Assim, é fundamental a adequada identificação de suas causas, bem como a diferenciação com outras patologias distintas para adequada abordagem da deficiência de ferro. Neste artigo são brevemente descritas outras condições que podem cursar com anemia microcítica, tais como: talassemias, anemia de doença crônica, anemia sideroblástica e envenenamento por chumbo, patologias estas que devem ser afastadas durante investigação de anemia ferropriva.Iron deficiency is considered to be the commonest hematological pathology in humans. Thus, the essential steps in an adequate approach of iron deficiency include: the proper identification of its causes and the differentiation between iron deficiency and other conditions. This article briefly describes other conditions that may present with microcytic anemia such as thalassemia, anemia of chronic diseases, sideroblastic anemia and lead intoxication. These diseases should be considered during the investigation of iron deficiency anemia.

Effect of argon addition into oxygen atmosphere on YBCO thin films deposition

International Nuclear Information System (INIS)

Mozhaev, P. B.; Borisenko, I. V.; Ovsyannikov, G. A.; Kuehle, A.; Bindslev-Hansen, J.; Johannes, L.; Skov, J. L.

2002-01-01

Multicomponent nature of the YBa 2 Cu 3 O x (YBCO) high-temperature superconductor makes difficult fabrication of smooth thin films: every local deviation from stoichiometry can result in seeding of a non-superconducting oxide particle. High density of such particles on typical YBCO thin film surface, however, presumes overall non-stoichiometry of the film. Such an effect can result from (i) non-uniform material transport from target to substrate, and (ii) re-evaporation or re-sputtering from the growing film surface. The first reason is more usual for laser ablation deposition technique, the second is typical for long sputtering deposition processes. Substitution of oxygen with argon in the deposition atmosphere improves surface quality of YBCO thin films deposited both by laser ablation and DC-sputtering at high pressure techniques. In the first case, the ablated species are scattered different ways in the oxygen atmosphere. Addition of argon decreases the inelastic scattering of barium; the proper part of Ar in the deposition atmosphere makes scattering and, hence, transport of all atoms uniform. The YBCO films deposited by DC-sputtering at high pressure technique are Ba-deficient also, but the reason is re-sputtering of Ba from the growing film as a result of negative oxygen ions bombardment. Such bombardment can lead also to chemical interaction of the deposited material with the substrate, as in the case of deposition of YBCO thin film on the CeO 2 buffer layer on sapphire. Substitution of oxygen with argon not only suppresses ion bombardment of the film, but also increases discharge stability due to presence of positive Ar + ions. The limiting factor of argon substitution is sufficient oxygenation of the growing oxide film. When oxygen partial pressure is too small, the superconducting quality of the YBCO thin film decreases and such a decrease cannot be overcome by prolonged oxygenation after deposition. (Authors)

The oxygen-binding properties of hemocyanin from the mollusk Concholepas concholepas.

Science.gov (United States)

González, Andrea; Nova, Esteban; Del Campo, Miguel; Manubens, Augusto; De Ioannes, Alfredo; Ferreira, Jorge; Becker, María Inés

2017-12-01

Hemocyanins have highly conserved copper-containing active sites that bind oxygen. However, structural differences among the hemocyanins of various mollusks may affect their physicochemical properties. Here, we studied the oxygen-binding cooperativity and affinity of Concholepas concholepas hemocyanin (CCH) and its two isolated subunits over a wide range of temperatures and pH values. Considering the differences in the quaternary structures of CCH and keyhole limpet hemocyanin (KLH), we hypothesized that the heterodidecameric CCH has different oxygen-binding parameters than the homodidecameric KLH. A novel modification of the polarographic method was applied in which rat liver submitochondrial particles containing cytochrome c oxidase were introduced to totally deplete oxygen of the test solution using ascorbate as the electron donor. This method was both sensitive and reproducible. The results showed that CCH, like other hemocyanins, exhibits cooperativity, showing an inverse relationship between the oxygen-binding parameters and temperature. According to their Hill coefficients, KLH has greater cooperativity than CCH at physiological pH; however, CCH is less sensitive to pH changes than KLH. Appreciable differences in binding behavior were found between the CCH subunits: the cooperativity of CCH-A was not only almost double that of CCH-B, but it was also slightly superior to that of CCH, thus suggesting that the oxygen-binding domains of the CCH subunits are different in their primary structure. Collectively, these data suggest that CCH-A is the main oxygen-binding domain in CCH; CCH-B may play a more structural role, perhaps utilizing its surprising predisposition to form tubular polymers, unlike CCH-A, as demonstrated here using electron microscopy. Copyright © 2017 Elsevier B.V. All rights reserved.

Energy production from distillery wastewater using single and double-phase upflow anaerobic sludge blanket (UASB) reactor

Energy Technology Data Exchange (ETDEWEB)

Muyodi, F J; Rubindamayugi, M S.T. [Univ. of Dar es Salaam, Applied Microbiology Unit (Tanzania, United Republic of)

1998-12-31

A Single-phase (SP) and Double-phase (DP) Upflow Anaerobic Sludge Blanket (UASB) reactors treating distillery wastewater were operated in parallel. The DP UASB reactor showed better performance than the SP UASB reactor in terms of maximum methane production rate, methane content and Chemical Oxygen Demand (COD) removal efficiency. (au) 20 refs.

Energy production from distillery wastewater using single and double-phase upflow anaerobic sludge blanket (UASB) reactor

Energy Technology Data Exchange (ETDEWEB)

Muyodi, F.J.; Rubindamayugi, M.S.T. [Univ. of Dar es Salaam, Applied Microbiology Unit (Tanzania, United Republic of)

1997-12-31

A Single-phase (SP) and Double-phase (DP) Upflow Anaerobic Sludge Blanket (UASB) reactors treating distillery wastewater were operated in parallel. The DP UASB reactor showed better performance than the SP UASB reactor in terms of maximum methane production rate, methane content and Chemical Oxygen Demand (COD) removal efficiency. (au) 20 refs.

Mass-spectrometric analysis of trace oxygen in carbon dioxide; Analyse de traces d'oxygene dans le gaz carbonique par spectrometrie de masse

Energy Technology Data Exchange (ETDEWEB)

Nief, G; Severin, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1961-07-01

The mass spectrum of pure CO{sub 2} contains a peak of weight 32 whose relationship to peak at 44 varies greatly depending on the previous history of the source of ions and even during the course of an analysis. The fact that this peak is more or less proportional to the pressure and that its appearance potential is the same as that of oxygen leads us to suppose that it is produced from oxygen formed by dissociation of the carbon dioxide on the tungsten filament. A prior treatment of the ion source with acetylene reduces the ratio 32/44 to a value of about 15.10{sup -5}. This same treatment also stabilises the spectrometer's sensitivity to oxygen. Two lines of introduction enable pure carbon dioxide, the specimen to be estimated and a reference mixture of known oxygen content to be sent into the mass spectrometer in quick succession. Oxygen in the carbon dioxide in amounts ranging between 0 and 500 p.p.m. can thus be determined to an accuracy of {+-} 5 p.p.m., the analysis taking 30 minutes. (author) [French] Le spectre de masse de CO{sub 2} pur contient un pic de masse 32 dont le rapport au pic 44 varie enormement suivant l'histoire anterieure de la source d'ions et meme au cours d'une analyse. Le fait que ce pic soit grossierement proportionnel a la pression et que son potentiel d'apparition soit le meme que celui de l'oxygene permet de supposer qu'il est engendre a partir de l'oxygene produit par dissociation du gaz carbonique sur le filament de tungstene. Un conditionnement prealable de la source d'ions avec de l'acetylene reduit le rapport 32/44 a une valeur d'environ 15.10{sup -5}. Ce meme traitement stabilise egalement la sensibilite du spectrometre vis-a-vis de l'oxygene. Une double ligne d'introduction de gaz permet d'envoyer en successions rapides dans le spectrometre de masse le gaz carbonique pur, l'echantillon a doser et un melange de reference de teneur en oxygene connue. On arrive ainsi a doser l'oxygene dans le gaz carbonique dans la gamme de 0 a

ABOUT A CHOICE OF MATHEMATICAL MODELS OF KINETICS OF CULTIVATION OF SACCHAROMYCES CEREVISIAE YEAST IN THE CONDITIONS OF DEFICIENCY OF OXYGEN

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V. B. Tishin

2015-01-01

Full Text Available Summary. In the production technology of many foods microbiological processes are crucial to the economic indicators of enterprises and the quality of the products manufactured. The examples of this are the production, where the biomass is the end product. For example, the production of various strains of the yeast Saccharomyces for different branches of the food industry: baking, brewing, winemaking, as well as for the pharmaceutical industry. The development of mathematical models of microbial cells is one of the greatest challenges of microbiology. The need to search for mathematical models is dictated by the continuous development of microbiological industry, increases in the requirements for the production design, maintenance and predictions of the processes depending on the change of process parameters. However, this requires knowledge of the laws governing material and energy exchange between the culture medium and the cell and the availability of mathematical models describing them. This knowledge cannot be obtained without studying the biological processes kinetics. Kinetic regularities of microbial growth is largely determined by the selection method of the microbiological process and the type of equipment in which these processes occur. Many biological processes can be described with a simple mathematical model, but there are kinetic regularities of biological processes that can only be described by equations of more complex type. Culturing yeast kinetic models, reflecting the complexity of the biological processes occurring during the cultivation were obtained. According to the analysis of experimental data on the Saccharomyces cerevisiae yeast culturing with a batch process, a system of equations (mathematical model, giving a functional relationship of biomass growth and cells consumption of carbohydrates with their different initial values in a culture medium under conditions of oxygen deficiency without stirring is obtained.

Polarization properties of La0.6Sr0.4Co0.2Fe0.8O3-based double layer-type oxygen electrodes for reversible SOFCs

International Nuclear Information System (INIS)

Tao, Y.; Nishino, H.; Ashidate, S.; Kokubo, H.; Watanabe, M.; Uchida, H.

2009-01-01

We have developed double layer-type (catalyst layer/current collecting layer) oxygen electrodes (DLE) for reversible SOFCs. As the catalyst layer (cathode for SOFC and anode for steam electrolysis) interfaced with a samaria-doped ceria [(CeO 2 ) 0.8 (SmO 1.5 ) 0.2 , SDC] interlayer/YSZ solid electrolyte, mixed conducting La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 (LSCF) and SDC particles were employed. The current collecting porous LSCF layer was formed on the catalyst layer. By controlling the SDC content, as well as the thickness and porosity of the catalyst layer, the gas diffusion rate and the conduction networks for electrons and oxide ions were optimized, resulting in a marked reduction of the overpotential. The LSCF + SDC/LSCF DLE exhibited higher performance than single-layer electrodes of LSCF + SDC or LSCF; the IR-free anode potential vs. an air reference electrode was 0.12 V (corresponding to an overpotential of 0.08 V) at 0.5 A cm -2 and 900 deg. C under an atmosphere of O 2 (1 atm)

Deletion or Inhibition of the Oxygen Sensor PHD1 Protects against Ischemic Stroke via Reprogramming of Neuronal Metabolism.

Science.gov (United States)

Quaegebeur, Annelies; Segura, Inmaculada; Schmieder, Roberta; Verdegem, Dries; Decimo, Ilaria; Bifari, Francesco; Dresselaers, Tom; Eelen, Guy; Ghosh, Debapriva; Davidson, Shawn M; Schoors, Sandra; Broekaert, Dorien; Cruys, Bert; Govaerts, Kristof; De Legher, Carla; Bouché, Ann; Schoonjans, Luc; Ramer, Matt S; Hung, Gene; Bossaert, Goele; Cleveland, Don W; Himmelreich, Uwe; Voets, Thomas; Lemmens, Robin; Bennett, C Frank; Robberecht, Wim; De Bock, Katrien; Dewerchin, Mieke; Ghesquière, Bart; Fendt, Sarah-Maria; Carmeliet, Peter

2016-02-09

The oxygen-sensing prolyl hydroxylase domain proteins (PHDs) regulate cellular metabolism, but their role in neuronal metabolism during stroke is unknown. Here we report that PHD1 deficiency provides neuroprotection in a murine model of permanent brain ischemia. This was not due to an increased collateral vessel network. Instead, PHD1(-/-) neurons were protected against oxygen-nutrient deprivation by reprogramming glucose metabolism. Indeed, PHD1(-/-) neurons enhanced glucose flux through the oxidative pentose phosphate pathway by diverting glucose away from glycolysis. As a result, PHD1(-/-) neurons increased their redox buffering capacity to scavenge oxygen radicals in ischemia. Intracerebroventricular injection of PHD1-antisense oligonucleotides reduced the cerebral infarct size and neurological deficits following stroke. These data identify PHD1 as a regulator of neuronal metabolism and a potential therapeutic target in ischemic stroke. Copyright © 2016 Elsevier Inc. All rights reserved.

Zolpidem reduces the blood oxygen level-dependent signal during visual system stimulation

OpenAIRE

Licata, Stephanie C.; Lowen, Steven B.; Trksak, George H.; MacLean, Robert R.; Lukas, Scott E.

2011-01-01

Zolpidem is a short-acting imidazopyridine hypnotic that binds at the benzodiazepine binding site on specific GABAA receptors to enhance fast inhibitory neurotransmission. The behavioral and receptor pharmacology of zolpidem has been studied extensively, but little is known about its neuronal substrates in vivo. In the present within-subject, double-blind, and placebo-controlled study, blood oxygen level-dependent functional magnetic resonance imaging (BOLD fMRI) at 3 Tesla was used to assess...

Thermochemical Properties of the Lattice Oxygen in W,Mn-Containing Mixed Oxide Catalysts for the Oxidative Coupling of Methane

Science.gov (United States)

Lomonosov, V. I.; Gordienko, Yu. A.; Sinev, M. Yu.; Rogov, V. A.; Sadykov, V. A.

2018-03-01

Mixed NaWMn/SiO2 oxide, samples containing individual components (Na, W, Mn) and their double combinations (Na-W, Na-Mn, W-Mn) supported on silica were studied by temperature programmed reduction (TPR) and desorption (TPD), and heat flow calorimetry during their reoxidation with molecular oxygen in pulse mode. The NaWMn/SiO2 mixed oxide was shown to contain two different types of reactive lattice oxygen. The weakly-bonded oxygen can be reversibly released from the oxide in a flow of inert gas in the temperature range of 575‒900°C, while the strongly-bonded oxygen can be removed during the reduction of the sample with hydrogen at 700-900°C. The measured thermal effect of oxygen consumption for these two oxygen forms are 185 and 350 kJ/mol, respectively. The amount of oxygen removed at reduction ( 443 μmol/g) considerably exceeded the amount desorbed in an inert gas flow ( 56 μmol/g). The obtained results suggest that the reversible oxygen desorption is due to the redox process in which manganese ions are involved, while during the temperature programmed reduction, mainly oxygen bonded with tungsten is removed.

New Insights Into the Role of Estrogens in Male Fertility Based on Findings in Aromatase-Deficient Zebrafish.

Science.gov (United States)

Tang, Haipei; Chen, Yu; Liu, Yun; Yin, Yike; Li, Gaofei; Guo, Yin; Liu, Xiaochun; Lin, Haoran

2017-09-01

It has been demonstrated that estrogens are indispensable for male fertility in mammals. Aromatase (encoded by CYP19) catalyzes the final step of estradiol biosynthesis. However, less is known about the role of aromatase in male fertility in nonmammalian species. Fish aromatase is encoded by two separate genes: the gonad-specific cyp19a1a and the brain-specific cyp19a1b. In a recent study, we used transcription activatorlike effector nucleases to systematically generate cyp19a1a and cyp19a1b mutant lines and a cyp19a1a;cyp19a1b double-mutant line in zebrafish and demonstrated that cyp19a1a was indispensable for sex differentiation. In this study, we focused on male fertility in these aromatase-deficient zebrafish. Our results showed that all aromatase-deficient male fish had normal fertility even at 1 year after fertilization. Interestingly, we observed more spermatozoa in the cyp19a1a and double-mutant males than in the wild-type and cyp19a1b mutant males. The whole-body androgen levels, follicle-stimulating hormone β and luteinizing hormone β protein levels in the pituitary, and transcript levels of genes known to be involved in spermatogenesis and steroidogenesis in the testes were significantly higher in the cyp19a1a mutant and aromatase double-mutant males than in the wild-type and cyp19a1b mutant males. These results might explain why more spermatozoa were observed in these fish. Collectively, our findings indicate that estrogens are not needed to achieve and maintain normal fertility in male zebrafish. This finding challenges the traditional view that estrogens are indispensable for male fertility. Copyright © 2017 Endocrine Society.

Deficiency of Nox2 prevents angiotensin II-induced inward remodeling in cerebral arterioles

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Siu-Lung eChan

2013-06-01

Full Text Available Angiotensin II is an important determinant of inward remodeling in cerebral arterioles. Many of the vascular effects of angiotensin II are mediated by reactive oxygen species generated from homologues of NADPH oxidase with Nox2 predominating in small arteries and arterioles. Therefore, we tested the hypothesis that superoxide generated by Nox2 plays a role in angiotensin II-induced cerebral arteriolar remodeling. We examined Nox2-deficient and wild-type mice in which a pressor or a non-pressor dose of angiotensin II (1000 or 200 ng/kg/day or saline was infused for 4 weeks via osmotic minipumps. Systolic arterial pressure was measured by a tail-cuff method. Pressure and diameter of cerebral arterioles were measured through an open cranial window in anesthetized mice. Cross-sectional area (by histology and superoxide level (by hydroethidine staining of cerebral arterioles were determined ex vivo. The pressor, but not the non-pressor, dose of angiotensin II significantly increased systolic arterial pressure in both wild-type and Nox2-deficient mice. Both doses of angiotensin II increased superoxide levels and significantly reduced external diameter in maximally dilated cerebral arterioles in wild-type mice. Increased superoxide and inward remodeling were prevented in Nox2-deficient mice. Moreover, only the pressor dose of AngII increased cross-sectional area of arteriolar wall in wild-type mice and was prevented in Nox2-deficient mice. In conclusion, superoxide derived from Nox2-containing NADPH oxidase plays an important role in angiotensin II-mediated inward remodeling in cerebral arterioles. This effect appears to be independent of pressure and different from that of hypertrophy.

Warming can boost denitrification disproportionately due to altered oxygen dynamics.

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Annelies J Veraart

Full Text Available BACKGROUND: Global warming and the alteration of the global nitrogen cycle are major anthropogenic threats to the environment. Denitrification, the biological conversion of nitrate to gaseous nitrogen, removes a substantial fraction of the nitrogen from aquatic ecosystems, and can therefore help to reduce eutrophication effects. However, potential responses of denitrification to warming are poorly understood. Although several studies have reported increased denitrification rates with rising temperature, the impact of temperature on denitrification seems to vary widely between systems. METHODOLOGY/PRINCIPAL FINDINGS: We explored the effects of warming on denitrification rates using microcosm experiments, field measurements and a simple model approach. Our results suggest that a three degree temperature rise will double denitrification rates. By performing experiments at fixed oxygen concentrations as well as with oxygen concentrations varying freely with temperature, we demonstrate that this strong temperature dependence of denitrification can be explained by a systematic decrease of oxygen concentrations with rising temperature. Warming decreases oxygen concentrations due to reduced solubility, and more importantly, because respiration rates rise more steeply with temperature than photosynthesis. CONCLUSIONS/SIGNIFICANCE: Our results show that denitrification rates in aquatic ecosystems are strongly temperature dependent, and that this is amplified by the temperature dependencies of photosynthesis and respiration. Our results illustrate the broader phenomenon that coupling of temperature dependent reactions may in some situations strongly alter overall effects of temperature on ecological processes.

Singlet Oxygen Reactions with Flavonoids. A Theoretical – Experimental Study

Science.gov (United States)

Morales, Javier; Günther, Germán; Zanocco, Antonio L.; Lemp, Else

2012-01-01

Detection of singlet oxygen emission, λmax = 1270 nm, following laser excitation and steady-state methods were employed to measure the total reaction rate constant, kT, and the reactive reaction rate constant, kr, for the reaction between singlet oxygen and several flavonoids. Values of kT determined in deuterated water, ranging from 2.4×107 M−1s−1 to 13.4×107 M−1s−1, for rutin and morin, respectively, and the values measured for kr, ranging from 2.8×105 M−1s−1 to 65.7×105 M−1s−1 for kaempferol and morin, respectively, being epicatechin and catechin chemically unreactive. These results indicate that all the studied flavonoids are good quenchers of singlet oxygen and could be valuable antioxidants in systems under oxidative stress, in particular if a flavonoid-rich diet was previously consumed. Analysis of the dependence of rate constant values with molecular structure in terms of global descriptors and condensed Fukui functions, resulting from electronic structure calculations, supports the formation of a charge transfer exciplex in all studied reactions. The fraction of exciplex giving reaction products evolves through a hydroperoxide and/or an endoperoxide intermediate produced by singlet oxygen attack on the double bond of the ring C of the flavonoid. PMID:22802966

Menadione stress in Saccharomyces cerevisiae strains deficient in the glutathione transferases.

Science.gov (United States)

Castro, F A V; Herdeiro, R S; Panek, A D; Eleutherio, E C A; Pereira, M D

2007-02-01

Using S. cerevisiae as a eukaryotic cell model we have analyzed the involvement of both glutathione transferase isoforms, Gtt1 and Gtt2, in constitutive resistance and adaptive response to menadione, a quinone which can exert its toxicity as redox cycling and/or electrophiles. The detoxification properties, of these enzymes, have also been analyzed by the appearance of S-conjugates in the media. Direct exposure to menadione (20 mM/60 min) showed to be lethal for cells deficient on both Gtt1 and Gtt2 isoforms. However, after pre-treatment with a low menadione concentration, cells deficient in Gtt2 displayed reduced ability to acquire tolerance when compared with the control and the Gtt1 deficient strains. Analyzing the toxic effects of menadione we observed that the gtt2 mutant showed no reduction in lipid peroxidation levels. Moreover, measuring the levels of intracellular oxidation during menadione stress we have shown that the increase of this oxidative stress parameter was due to the capacity menadione possesses in generating reactive oxygen species (ROS) and that both GSH and Gtt2 isoform were required to enhance ROS production. Furthermore, the efflux of the menadione-GSH conjugate, which is related with detoxification of xenobiotic pathways, was not detected in the gtt2 mutant. Taken together, these results suggest that acquisition of tolerance against stress generated by menadione and the process of detoxification through S-conjugates are dependent upon Gtt2 activity. This assessment was corroborated by the increase of GTT2 expression, and not of GTT1, after menadione treatment.

Study on iron metabolism in children using double labelling of 51Cr and 59Fe

International Nuclear Information System (INIS)

Kobayashi, Masatsura

1974-01-01

In the children before and after treatment for iron deficiency anemia and those on ingesting a long-term low caloric and iron diet, life span of Ashby Technique 1/2(AST) red cells, circulatory blood volume (CBV), plasma iron disappearance(PID), red cell-iron utility(RCIU), plasma-iron turnover rate(PITR), and red cell-ironturnover rate(RCITR) were respectively determined using double labeling of 51 Cr and 59 Fe, and the following results and conclusions were obtained: In the patients with iron deficiency anemia, the rate of RCIU was highly increased, and simultaneously the shortening in AST was observed. Among the children with the iron deficiency anemia, five patients were examined immediately after the improvement on the anemia by iron drugs; the serum iron (SFe) averaged 74μg/ml. So the erthropiesis appeared to recover to normal, yet AST has hardly changed, still more has it shortened. In five children with celebral palsy associated with disturbance of physical development, who had ingested a long-term liquid low iron diet no evident increase of RCIU was found except for high calues of RCITR. The shortening in AST was not entirely seen in contrast with that of the simple alimentary iron deficiency anemia. Besides the CBV measured par kg of weight showed the remarkable increase. (Oyama, S.)

Treatment in carbon monoxide poisoning patients with headache: a prospective, multicenter, double-blind, controlled clinical trial.

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Ocak, Tarik; Tekin, Erdal; Basturk, Mustafa; Duran, Arif; Serinken, Mustafa; Emet, Mucahit

2016-11-01

There is a lack of specificity of the analgesic agents used to treat headache and underlying acute carbon monoxide poisoning. To compare effectiveness of "oxygen alone" vs "metoclopramide plus oxygen" vs "metamizole plus oxygen" therapy in treating carbon monoxide-induced headache. A prospective, multicenter, double-blind, controlled trial. Three emergency departments in Turkey. Adult carbon monoxide poisoning patients with headache. A total of 117 carbon monoxide-intoxicated patients with headache were randomized into 3 groups and assessed at baseline, 30 minutes, 90 minutes, and 4 hours. The primary outcome was patient-reported improvement rates for headache. Secondary end points included nausea, need for rescue medication during treatment, and reduction in carboxyhemoglobin levels. During observation, there was no statistical difference between drug type and visual analog scale score change at 30 minutes, 90 minutes, or 4 hours, for either headache or nausea. No rescue medication was needed during the study period. The reduction in carboxyhemoglobin levels did not differ among the 3 groups. The use of "oxygen alone" is as efficacious as "oxygen plus metoclopramide" or "oxygen plus metamizole sodium" in the treatment of carbon monoxide-induced headache. Copyright © 2016 Elsevier Inc. All rights reserved.

Nitrous oxide production by nitrification and denitrification in the Eastern Tropical South Pacific oxygen minimum zone

Science.gov (United States)

Ji, Qixing; Babbin, Andrew R.; Jayakumar, Amal; Oleynik, Sergey; Ward, Bess B.

2015-12-01

The Eastern Tropical South Pacific oxygen minimum zone (ETSP-OMZ) is a site of intense nitrous oxide (N2O) flux to the atmosphere. This flux results from production of N2O by nitrification and denitrification, but the contribution of the two processes is unknown. The rates of these pathways and their distributions were measured directly using 15N tracers. The highest N2O production rates occurred at the depth of peak N2O concentrations at the oxic-anoxic interface above the oxygen deficient zone (ODZ) because slightly oxygenated waters allowed (1) N2O production from both nitrification and denitrification and (2) higher nitrous oxide production yields from nitrification. Within the ODZ proper (i.e., anoxia), the only source of N2O was denitrification (i.e., nitrite and nitrate reduction), the rates of which were reflected in the abundance of nirS genes (encoding nitrite reductase). Overall, denitrification was the dominant pathway contributing the N2O production in the ETSP-OMZ.

Molecular characterization of FXI deficiency.

Science.gov (United States)

Berber, Ergul

2011-02-01

Factor XI (FXI) deficiency is a rare autosomal bleeding disease associated with genetic defects in the FXI gene. It is a heterogeneous disorder with variable tendency in bleeding and variable causative FXI gene mutations. It is characterized as a cross-reacting material-negative (CRM-) FXI deficiency due to decreased FXI levels or cross-reacting material-positive (CRM+) FXI deficiency due to impaired FXI function. Increasing number of mutations has been reported in FXI mutation database, and most of the mutations are affecting serine protease (SP) domain of the protein. Functional characterization for the mutations helps to better understand the molecular basis of FXI deficiency. Prevalence of the disease is higher in certain populations such as Ashkenazi Jews. The purpose of this review is to give an overview of the molecular basis of congenital FXI deficiency.

Premature Senescence Induced by Ionizing Radiation Requires AKT Activity and Reactive Oxygen Species in Glioma

International Nuclear Information System (INIS)

Lee, Je Jung; Kim, Bong Cho; Yoo, Hee Jung; Lee, Jae Seon

2010-01-01

Loss of PTEN, a tumor suppressor gene has frequently observed in human gliomas, which conferred AKT activation and resistance to ionizing radiation (IR) and anti-cancer drugs. Recent reports have shown that AKT activation induces premature senescence through increase of oxygen consumption and inhibition of expression of ROS scavenging enzymes. In this study, we compared cellular response to IR in the PTEN-deficient U87, U251, U373 or PTEN-proficient LN18, LN428 glioma cells

Adaptive aneuploidy protects against thiol peroxidase deficiency by increasing respiration via key mitochondrial proteins.

Science.gov (United States)

Kaya, Alaattin; Gerashchenko, Maxim V; Seim, Inge; Labarre, Jean; Toledano, Michel B; Gladyshev, Vadim N

2015-08-25

Aerobic respiration is a fundamental energy-generating process; however, there is cost associated with living in an oxygen-rich environment, because partially reduced oxygen species can damage cellular components. Organisms evolved enzymes that alleviate this damage and protect the intracellular milieu, most notably thiol peroxidases, which are abundant and conserved enzymes that mediate hydrogen peroxide signaling and act as the first line of defense against oxidants in nearly all living organisms. Deletion of all eight thiol peroxidase genes in yeast (∆8 strain) is not lethal, but results in slow growth and a high mutation rate. Here we characterized mechanisms that allow yeast cells to survive under conditions of thiol peroxidase deficiency. Two independent ∆8 strains increased mitochondrial content, altered mitochondrial distribution, and became dependent on respiration for growth but they were not hypersensitive to H2O2. In addition, both strains independently acquired a second copy of chromosome XI and increased expression of genes encoded by it. Survival of ∆8 cells was dependent on mitochondrial cytochrome-c peroxidase (CCP1) and UTH1, present on chromosome XI. Coexpression of these genes in ∆8 cells led to the elimination of the extra copy of chromosome XI and improved cell growth, whereas deletion of either gene was lethal. Thus, thiol peroxidase deficiency requires dosage compensation of CCP1 and UTH1 via chromosome XI aneuploidy, wherein these proteins support hydroperoxide removal with the reducing equivalents generated by the electron transport chain. To our knowledge, this is the first evidence of adaptive aneuploidy counteracting oxidative stress.

Development of oxygen and pH sensors for aqueous systems

International Nuclear Information System (INIS)

Stvartak, C.; Alcock, C.B.; Li, B.; Wang, L.; Fergus, J.W.; Bakshi, N.

1994-04-01

Corrosion science has long recognized that two of the most important parameters in characterizing the corrosivity of an aqueous environment are oxygen chemical potential and pH. These parameters not only determine the thermodynamic driving forces for various corrosion reactions, but also characterize the rates of these reactions and hence the lifetime of a particular component. The primary goal of this project is to develop an electrochemical oxygen and pH sensor for continuous use in the cycle chemistry control of power plants. In the past year, electrochemical sensors with a metal/metal oxide or metal/metal hydride internal reference electrode and a fluoride-based electrolyte tube have been developed and tested in this laboratory. The corrosion tests showed that the LaF 3 -based solid electrolyte was very stable both chemically and physically in water. Furthermore, its electrical conductivity is 4 to 5 orders of magnitude higher than that of stabilized zirconia below 573 K (300 degree C), which is the main advantage of a fluoride-based electrolyte at low temperatures. With this electrolyte and the selected internal oxygen reference electrode (Ag/Ag 2 O), the electrochemical probe demonstrated Nernstian responses to the oxygen chemical potential and pH of the aqueous solution with good reproducibility. A similar cell with Zr/ZrH 1+x as the internal hydrogen reference electrode showed promising pH sensing characteristics. It is proposed that these two cells be combined to form a double-headed electrochemical probe to determine oxygen chemical potential and pH in the solution simultaneously

Multimillennium changes in dissolved oxygen under global warming: results from an AOGCM and offline ocean biogeochemical model

Science.gov (United States)

Yamamoto, A.; Abe-Ouchi, A.; Shigemitsu, M.; Oka, A.; Takahashi, K.; Ohgaito, R.; Yamanaka, Y.

2016-12-01

Long-term oceanic oxygen change due to global warming is still unclear; most future projections (such as CMIP5) are only performed until 2100. Indeed, few previous studies using conceptual models project oxygen change in the next thousands of years, showing persistent global oxygen reduction by about 30% in the next 2000 years, even after atmospheric carbon dioxide stops rising. Yet, these models cannot sufficiently represent the ocean circulation change: the key driver of oxygen change. Moreover, considering serious effect oxygen reduction has on marine life and biogeochemical cycling, long-term oxygen change should be projected for higher validity. Therefore, we used a coupled atmosphere-ocean general circulation model (AOGCM) and an offline ocean biogeochemical model, investigating realistic long-term changes in oceanic oxygen concentration and ocean circulation. We integrated these models for 2000 years under atmospheric CO2 doubling and quadrupling. After global oxygen reduction in the first 500 years, oxygen concentration in deep ocean globally recovers and overshoots, despite surface oxygen decrease and weaker Atlantic Meridional Overturning Circulation. Deep ocean convection in the Weddell Sea recovers and overshoots, after initial cessation. Thus, enhanced deep convection and associated Antarctic Bottom Water supply oxygen-rich surface waters to deep ocean, resulting global deep ocean oxygenation. We conclude that the change in ocean circulation in the Southern Ocean potentially drives millennial-scale oxygenation in the deep ocean; contrary to past reported long-term oxygen reduction and general expectation. In presentation, we will discuss the mechanism of response of deep ocean convection in the Weddell Sea and show the volume changes of hypoxic waters.

Generation of intensity covariations of the oxygen green and red lines in the nightglow

Science.gov (United States)

Misawa, K.; Takeuchi, I.; Kato, Y.; Aoyama, I.

1984-02-01

The cause of intensity covariations of the oxygen green and red lines is studied. Intensity covariations are compared with the auroral-electrojet-activity index AE, the substorm Pi2, and the magnetogram. It is suggested that intensity covariations or double-intensity maxima of the red line occur in association with intense auroral substorms, and that they are the direct experimental evidences of Testud's theory (1973).

Vitamin B12 deficiency

DEFF Research Database (Denmark)

Green, Ralph; Allen, Lindsay H; Bjørke-Monsen, Anne-Lise

2017-01-01

, subclinical deficiency affects between 2.5% and 26% of the general population depending on the definition used, although the clinical relevance is unclear. B12 deficiency can affect individuals at all ages, but most particularly elderly individuals. Infants, children, adolescents and women of reproductive age...... remain debated. Management depends on B12 supplementation, either via high-dose oral routes or via parenteral administration. This Primer describes the current knowledge surrounding B12 deficiency, and highlights improvements in diagnostic methods as well as shifting concepts about the prevalence, causes...

The relation of double peaks, observed in quartz hydride atomizers, to the fate of free analyte atoms in the determination of arsenic and selenium by atomic absorption spectrometry

International Nuclear Information System (INIS)

D'Ulivo, Alessandro; Dedina, Jiri

2002-01-01

The mechanism at the origin of double peaks formation in quartz hydride atomizers were investigated by continuous flow hydride generation atomic absorption spectrometry. Arsenic and selenium were used as model analytes. The effect of atomization mode (flame-in-gas-shield (FIGS), miniature diffusion flame and double flame (DF)) and some experimental parameters as oxygen supply rate for microflame and the distance from atomization to free atoms detection point, were investigated on the shape of both analytical signals and calibration graphs. Rollover of calibration graphs and double peak formation are strictly related each to the other and could be observed only in FIGS atomizer mode under some particular conditions. A mechanism based on incomplete atomization of hydrides cannot explain the collected experimental evidences because the microflame of FIGS is able to produce quantitative atomization of large amount of hydrides even at supply rate of oxygen close to extinction threshold of microflame. The heterogeneous gas-solid reactions between finely dispersed particles, formed by free atom recombination, and the free atoms in the gaseous phase are at the origin of double peak formation

Genetics Home Reference: tyrosine hydroxylase deficiency

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... Email Facebook Twitter Home Health Conditions TH deficiency Tyrosine hydroxylase deficiency Printable PDF Open All Close All ... Javascript to view the expand/collapse boxes. Description Tyrosine hydroxylase (TH) deficiency is a disorder that primarily ...

Double-double effect and coordination number

International Nuclear Information System (INIS)

Mioduski, T.

1992-01-01

The original method of interpretation together with its theoretical foundations is developed, making it possible to use location and direction of the double-double (tetrad) effect within the Ln and An series to determine the coordination number (CN) complexes of the f-block elements. The method is applied for potentiometric and radiometric equilibrium studies. It has been pointed and that the decisive factor for the direction of the double-double effect in the case of the Gibbs energy variations is a difference in the CN of the f-element ion between the reaction product complex and that for the reaction substrate the ''regular'' effect for a given tetrad is accompanied by decrease in the CN while the ''reverse'' effect by increase in the CN. (author). 122 refs, 5 tabs, 8 figs

Influence of N deficiency and salinity on metal (Pb, Zn and Cu) accumulation and tolerance by Rhizophora stylosa in relation to root anatomy and permeability

International Nuclear Information System (INIS)

Cheng Hao; Wang Youshao; Ye Zhihong; Chen Danting; Wang Yutu; Peng Yalan; Wang Liying

2012-01-01

Effects of N deficiency and salinity on root anatomy, permeability and metal (Pb, Zn and Cu) translocation and tolerance were investigated using mangrove seedlings of Rhizophora stylosa. The results showed that salt could directly reduce radial oxygen loss (ROL) by stimulation of lignification within exodermis. N deficiency, oppositely, would reduce lignification. Such an alteration in root permeability may also influence metal tolerance by plants. The data indicated that a moderate salinity could stimulate a lignified exodermis that delayed the entry of metals into the roots and thereby contributed to a higher metal tolerance, while N deficiency would aggravate metal toxicity. The results from sand pot trail further confirmed this issue. This study provides a barrier property of the exodermis in dealing with environments. The plasticity of root anatomy is likely an adaptive strategy to regulate the fluxes of gases, nutrients and toxins at root–soil interface. - Highlights: ► Salt induced lignified exodermis which slowed down metal entry into the plants. ► N deficiency, oppositely, aggravated metal mobility and toxicity. ► Barrier properties of the exodermis. - N deficiency and salinity regulate the apoplastic transport barrier of metals and their toxicities

Genetics Home Reference: factor VII deficiency

Science.gov (United States)