WorldWideScience

Sample records for oxygen subset additionally

  1. Development of oxygen scavenger additives for jet fuels

    Energy Technology Data Exchange (ETDEWEB)

    Beaver, B.D.; Demunshi, R.; Sharief, V.; Tian, D.; Teng, Y. [Duquesne Univ., Pittsburgh, PA (United States)

    1995-05-01

    Our current research program is in response to the US Air Force`s FY93 New Initiative entitled {open_quotes}Advanced Fuel Composition and Use.{close_quotes} The critical goal of this initiative is to develop aircraft fuels which can operate at supercritical conditions. This is a vital objective since future aircraft designs will transfer much higher heat loads into the fuel as compared with current heat loads. In this paper it is argued that the thermal stability of most jet fuels would be dramatically improved by the efficient in flight-removal of a fuel`s dissolved oxygen. It is proposed herein to stabilize the bulk fuel by the addition of an additive which will be judiciously designed and programmed to react with oxygen and produce an innocuous product. It is envisioned that a thermally activated reaction will occur, between the oxygen scavenging additive and dissolved oxygen, in a controlled and directed manner. Consequently formation of insoluble thermal degradation products will be limited. It is believed that successful completion of this project will result in the development of a new type of jet fuel additive which will enable current conventional jet fuels to obtain sufficient thermal stability to function in significantly higher temperature regimes. In addition, it is postulated that the successful development of thermally activated oxygen scavengers will also provide the sub-critical thermal stability necessary for future development of endothermic fuels.

  2. CD44+CD24+ subset of PANC-1 cells exhibits radiation resistance via decreased levels of reactive oxygen species.

    Science.gov (United States)

    Wang, Lei; Li, Pengping; Hu, Wei; Xia, Youyou; Hu, Chenxi; Liu, Liang; Jiang, Xiaodong

    2017-08-01

    Emerging evidence has suggested that pancreatic adenocarcinoma is sustained by pancreatic cancer stem cells. The present study aimed to investigate the expression patterns of the pancreatic cancer stem cell surface markers cluster of differentiation CD44 and CD24 in a pancreatic adenocarcinoma cell line, and to investigate the possible mechanisms for their radiation resistance. Flow cytometry was used to analyze the expression patterns of CD44 and CD24 in the pancreatic adenocarcinoma PANC-1 cell line. In addition, a multi-target click model was used to fit cell survival curves and determine the sensitizer enhancement ratio. The apoptosis and cycle distribution of the four cell subsets was determined using flow cytometry, and the level of reactive oxygen species (ROS) was determined using the 2',7'-dichlorofluorescin diacetate probe. The present results identified that the ratios of CD44 + and CD24 + in the sorted PANC-1 cell line were 92.0 and 4.7%, respectively. Prior to radiation, no statistically significant differences were observed among the four groups. Following treatment with 6 MV of X-rays, the rate of apoptosis was decreased in the CD44 + CD24 + group compared with other subsets. The percentage of G0/G1 cells was highest in the CD44 + CD24 + group compared with the three other groups, which exhibited increased radiosensitivity. In addition, the level of ROS in the CD44 + CD24 + group was reduced compared with the other groups. In summary, the results of the present study indicated that CD44 + CD24 + exhibited stem cell properties. The lower level of ROS and apoptosis in CD44 + CD24 + cells may contribute to their resistance to radiation in pancreatic adenocarcinoma.

  3. EFFECT OF OXYGENATED HYDROCARBON ADDITIVES ON EXHAUST EMISSIONS OF A DIESEL ENGINE

    OpenAIRE

    C. Sundar Raj; S. Sendilvelan

    2010-01-01

    The use of oxygenated fuels seems to be a promising solution for reducing particulate emissions in existing and future diesel motor vehicles. In this work, the influence of the addition of oxygenated hydrocarbons to diesel fuels on performance and emission parameters of a diesel engine is experimentally studied. 3-Pentanone (C5H10O) and Methyl anon (C7H12O) were used as oxygenated fuel additives. It was found that the addition of oxygenated hydrocarbons reduced the production of soot precurs...

  4. High oxygen as an additional factor in food preservation

    NARCIS (Netherlands)

    Amanatidou, A.

    2001-01-01

    In this thesis, the efficacy of high oxygen as an additional hurdle for food preservation is studied. At high oxygen conditions and at low temperature, significant impairment of growth and viability of bacterial cells is found to occur as the result of free

  5. EFFECT OF OXYGENATED HYDROCARBON ADDITIVES ON EXHAUST EMISSIONS OF A DIESEL ENGINE

    Directory of Open Access Journals (Sweden)

    C. Sundar Raj

    2010-12-01

    Full Text Available The use of oxygenated fuels seems to be a promising solution for reducing particulate emissions in existing and future diesel motor vehicles. In this work, the influence of the addition of oxygenated hydrocarbons to diesel fuels on performance and emission parameters of a diesel engine is experimentally studied. 3-Pentanone (C5H10O and Methyl anon (C7H12O were used as oxygenated fuel additives. It was found that the addition of oxygenated hydrocarbons reduced the production of soot precursors with respect to the availability of oxygen content in the fuel. On the other hand, a serious increase of NOx emissions is observed. For this reason the use of exhaust gas recirculation (EGR to control NOx emissions is examined. From the analysis of it is examined experimental findings, it is seen that the use of EGR causes a sharp reduction in NOx and smoke simultaneously. On the other hand, EGR results in a slight reduction of engine efficiency and maximum combustion pressure which in any case does not alter the benefits obtained from the oxygenated fuel.

  6. Evaluation of Additively Manufactured Metals for Use in Oxygen Systems Project

    Science.gov (United States)

    Tylka, Jonathan; Cooper, Ken; Peralta, Stephen; Wilcutt, Terrence; Hughitt, Brian; Generazio, Edward

    2016-01-01

    Space Launch System, Commercial Resupply, and Commercial Crew programs have published intent to use additively manufactured (AM) components in propulsion systems and are likely to include various life support systems in the future. Parts produced by these types of additive manufacturing techniques have not been fully evaluated for use in oxygen systems and the inherent risks have not been fully identified. Some areas of primary concern in the SLS process with respect to oxygen compatibility may be the porosity of the printed parts, fundamental differences in microstructure of an AM part as compared to traditional materials, or increased risk of shed metal particulate into an oxygen system. If an ignition were to occur the printed material could be more flammable than components manufactured from a traditional billet of raw material and/or present a significant hazards if not identified and rigorously studied in advance of implementation into an oxygen system.

  7. Exposure to ultrafine particles, intracellular production of reactive oxygen species in leukocytes and altered levels of endothelial progenitor cells

    International Nuclear Information System (INIS)

    Jantzen, Kim; Møller, Peter; Karottki, Dorina Gabriela; Olsen, Yulia; Bekö, Gabriel; Clausen, Geo; Hersoug, Lars-Georg; Loft, Steffen

    2016-01-01

    Exposure to particles in the fine and ultrafine size range has been linked to induction of low-grade systemic inflammation, oxidative stress and development of cardiovascular diseases. Declining levels of endothelial progenitor cells within systemic circulation have likewise been linked to progression of cardiovascular diseases. The objective was to determine if exposure to fine and ultrafine particles from indoor and outdoor sources, assessed by personal and residential indoor monitoring, is associated with altered levels of endothelial progenitor cells, and whether such effects are related to leukocyte-mediated oxidative stress. The study utilized a cross sectional design performed in 58 study participants from a larger cohort. Levels of circulating endothelial progenitor cells, defined as either late (CD34 + KDR + cells) or early (CD34 + CD133 + KDR + cells) subsets were measured using polychromatic flow cytometry. We additionally measured production of reactive oxygen species in leukocyte subsets (lymphocytes, monocytes and granulocytes) by flow cytometry using intracellular 2′,7′-dichlorofluoroscein. The measurements encompassed both basal levels of reactive oxygen species production and capacity for reactive oxygen species production for each leukocyte subset. We found that the late endothelial progenitor subset was negatively associated with levels of ultrafine particles measured within the participant residences and with reactive oxygen species production capacity in lymphocytes. Additionally, the early endothelial progenitor cell levels were positively associated with a personalised measure of ultrafine particle exposure and negatively associated with both basal and capacity for reactive oxygen species production in lymphocytes and granulocytes, respectively. Our results indicate that exposure to fine and ultrafine particles derived from indoor sources may have adverse effects on human vascular health.

  8. Stimulation of aerobic degradation of bentazone, mecoprop and dichlorprop by oxygen addition to aquifer sediment

    Energy Technology Data Exchange (ETDEWEB)

    Levi, S.; Hybel, A.-M.; Bjerg, P.L.; Albrechtsen, H.-J., E-mail: hana@env.dtu.dk

    2014-03-01

    In order to investigate aerobic degradation potential for the herbicides bentazone, mecoprop and dichlorprop, anaerobic groundwater samples from two monitoring and three drinking water wells near a drinking water abstraction field in Nybølle, Denmark, were screened for their degradation potential for the herbicides. In the presence of oxygen {sup 14}C-labelled bentazone and mecoprop were removed significantly from the two monitoring wells' groundwater samples. Oxygen was added to microcosms in order to investigate whether different oxygen concentrations stimulate the biodegradation of the three herbicides in microcosms using groundwater and sandy aquifer materials. To maintain a certain oxygen concentration this level was measured from the outside of the bottles with a fibre oxygen meter using oxygen-sensitive luminescent sensor foil mounted inside the microcosm, to which supplementary oxygen was added. The highest oxygen concentrations (corresponding to 4–11 mg L{sup −1}) stimulated degradation (a 14–27% increase for mecoprop, 3–9% for dichlorprop and 15–20% for bentazone) over an experimental period of 200 days. Oxygen was required to biodegrade the herbicides, since no degradation was observed under anaerobic conditions. This is the first time bentazone degradation has been observed in aquifer material at low oxygen concentrations (2 mg L{sup −1}). The sediment had substantial oxygen consumption (0.92–1.45 O{sub 2} g{sup -1} dw over 200 days) and oxygen was depleted rapidly in most incubations soon after its addition, which might be due to the oxidation of organic matter and other reduced species such as Fe{sup 2+}, S{sup 2−} and Mn in sediment before the biodegradation of herbicides takes place. This study suggests that oxygen enhancement around a drinking water abstraction field could stimulate the bioremediation of diffuse source contamination. - Highlights: • Addition of different oxygen concentrations stimulated degradation of

  9. Stimulation of aerobic degradation of bentazone, mecoprop and dichlorprop by oxygen addition to aquifer sediment

    International Nuclear Information System (INIS)

    Levi, S.; Hybel, A.-M.; Bjerg, P.L.; Albrechtsen, H.-J.

    2014-01-01

    In order to investigate aerobic degradation potential for the herbicides bentazone, mecoprop and dichlorprop, anaerobic groundwater samples from two monitoring and three drinking water wells near a drinking water abstraction field in Nybølle, Denmark, were screened for their degradation potential for the herbicides. In the presence of oxygen 14 C-labelled bentazone and mecoprop were removed significantly from the two monitoring wells' groundwater samples. Oxygen was added to microcosms in order to investigate whether different oxygen concentrations stimulate the biodegradation of the three herbicides in microcosms using groundwater and sandy aquifer materials. To maintain a certain oxygen concentration this level was measured from the outside of the bottles with a fibre oxygen meter using oxygen-sensitive luminescent sensor foil mounted inside the microcosm, to which supplementary oxygen was added. The highest oxygen concentrations (corresponding to 4–11 mg L −1 ) stimulated degradation (a 14–27% increase for mecoprop, 3–9% for dichlorprop and 15–20% for bentazone) over an experimental period of 200 days. Oxygen was required to biodegrade the herbicides, since no degradation was observed under anaerobic conditions. This is the first time bentazone degradation has been observed in aquifer material at low oxygen concentrations (2 mg L −1 ). The sediment had substantial oxygen consumption (0.92–1.45 O 2 g -1 dw over 200 days) and oxygen was depleted rapidly in most incubations soon after its addition, which might be due to the oxidation of organic matter and other reduced species such as Fe 2+ , S 2− and Mn in sediment before the biodegradation of herbicides takes place. This study suggests that oxygen enhancement around a drinking water abstraction field could stimulate the bioremediation of diffuse source contamination. - Highlights: • Addition of different oxygen concentrations stimulated degradation of herbicides in anaerobic aquifer sediment

  10. Sodium addition and/or oxygen saturation of iohexol during normal and reduced perfusion pressure

    International Nuclear Information System (INIS)

    Baath, L.

    1990-01-01

    The influence on contractile force (CF) and the propensity for ventricular fibrillation (VF) from infusing the non-ionic contrast medium iohexol during normal (75 cm H 2 O) and reduced perfusion pressure (35 cm H 2 O) were investigated in the isolated rabbit heart. Both during normal and reduced perfusion pressure iohexol (150 mg I/ml) with oxygen saturation caused a smaller reduction of CF than iohexol without oxygen. During reduced pressure iohexol with sodium addition (28 mM NaCl) caused less depression of CF than iohexol without sodium. The combination of sodium addition and oxygen saturation had the least influence on CF. Iohexol (350 mg I/ml) without sodium had a similar fibrillatory propensity during both normal and reduced pressure. Enriching iohexol with 28 mM NaCl decreased the risk of VF. The decrease was similar during both normal and reduced pressure. The risk of VF from oxygen saturation of iohexol (350 mg I/ml, without sodium) was similar during both normal and reduced pressure. It is concluded that a small addition of sodium and/or oxygen saturation of a non-ionic monomeric contrast medium have beneficial effects on the heart both during normal perfusion pressure and during ischemia. (orig.)

  11. The combined effects of additives and supports on the synthesis of oxygenates over supported rhodium

    International Nuclear Information System (INIS)

    Chuang, S.C.; Tian, Y.; Goodwin, J.G. Jr.; Wender, I.

    1985-01-01

    There are potential advantages in the use of synthesis gas for the selective synthesis of oxygenated compounds rather than of hydrocarbons. This is due to the more versatile applications and higher value of oxygenates compared with that of hydrocarbons. Rh is known to be active in catalyzing, both heterogeneously and homogeneously, the formation of oxygenated compounds from synthesis gas. In a heterogeneous reaction system, the activity and selectivity of Rh catalysts are very sensitive to the chemical environment of Rh. By modifying its chemical environment through the use of various supports and/or with the addition of different promoters, Rh can selectively produce mostly oxygenates or mostly hydrocarbons. Studies have been carried out aimed at delineating the possible routes and intermediates involved in the formation of oxygenates and the function of additives (alkali promoters) and supports in the synthesis of oxygenates. Among the unpromoted Rh, the C/sub 2/ oxygenate selectivity decreased in the order: Rh/SiO/sub 2/ > Rh/MgO > Rh/La/sub 2/O/sub 3/ > Rh black, Rh/TiO/sub 2/ > Rh/Al/sub 2/O/sub 3/. High pressures improve selectivity to C/sub 2/ oxygenate compounds. Suppression of hydrogenation and ethanol dehydration was identified as major effects of alkali promotion. CO insertion was found to be dependent on both alkali promoters and on the supports. Results of ethanol addition indicated that the alkali species are located on both the Rh metal and on the support. The reaction network of CO hydrogenation on variously promoted catalysts is delineated, and the effect of secondary reactions on the overall product distribution is discussed

  12. Subset specification of central serotonergic neurons

    Directory of Open Access Journals (Sweden)

    Marten P Smidt

    2013-10-01

    Full Text Available The last decade the serotonin (5-hydroxytryptamine; 5-HT system has received enormous attention due to its role in regulation of behavior, exemplified by the discovery that increased 5-HT tone in the central nervous system is able to alleviate affective disorders. Here, we review the developmental processes, with a special emphasis on subset specification, leading to the formation of the 5-HT system in the brain. Molecular classification of 5-HT neuronal groups leads to the definition of two independent rostral groups positioned in rhombomere 1 and 2/3 and a caudal group in rhombomere 5-8. In addition, more disperse refinement of these subsets is present as shown by the selective expression of the 5-HT1A autoreceptor, indicating functional diversity between 5-HT subsets. The functional significance of the molecular coding differences is not well known and the molecular basis of described specific connectivity patterns remain to be elucidated. Recent developments in genetic lineage tracing models will provide these data and form a major step-up towards the full understanding of the importance of developmental programming and function of 5-HT neuronal subsets.

  13. Stimulation of aerobic degradation of bentazone, mecoprop and dichlorprop by oxygen addition to aquifer sediment

    DEFF Research Database (Denmark)

    Levi, Suzi; Hybel, Anne-Marie; Bjerg, Poul Løgstrup

    2014-01-01

    for the herbicides. In the presence of oxygen 14C-labelled bentazone and mecoprop were removed significantly from the two monitoring wells' groundwater samples. Oxygen was added to microcosms in order to investigate whether different oxygen concentrations stimulate the biodegradation of the three herbicides....... The highest oxygen concentrations (corresponding to 4-11mgL-1) stimulated degradation (a 14-27% increase for mecoprop, 3-9% for dichlorprop and 15-20% for bentazone) over an experimental period of 200days. Oxygen was required to biodegrade the herbicides, since no degradation was observed under anaerobic...... conditions. This is the first time bentazone degradation has been observed in aquifer material at low oxygen concentrations (2mgL-1). The sediment had substantial oxygen consumption (0.92-1.45O2g-1dw over 200days) and oxygen was depleted rapidly in most incubations soon after its addition, which might be due...

  14. Applying Additive Manufacturing to a New Liquid Oxygen Turbopump Design

    Science.gov (United States)

    O’Neal, T. Derek

    2016-01-01

    A liquid oxygen turbopump has been designed at Marshall Space Flight Center as part of the in-house, Advanced Manufacturing Demonstrator Engine (AMDE) project. Additive manufacturing, specifically direct metal laser sintering (DMLS) of Inconel 718, is used for 77% of the parts by mass. These parts include the impeller, turbine components, and housings. This paper discusses the impacts of the DMLS fabrication technique on the design of the turbopump and lessons learned during DMLS hardware fabrication and material testing.

  15. 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)

  16. Prediction based on mean subset

    DEFF Research Database (Denmark)

    Øjelund, Henrik; Brown, P. J.; Madsen, Henrik

    2002-01-01

    , it is found that the proposed mean subset method has superior prediction performance than prediction based on the best subset method, and in some settings also better than the ridge regression and lasso methods. The conclusions drawn from the Monte Carlo study is corroborated in an example in which prediction......Shrinkage methods have traditionally been applied in prediction problems. In this article we develop a shrinkage method (mean subset) that forms an average of regression coefficients from individual subsets of the explanatory variables. A Bayesian approach is taken to derive an expression of how...... the coefficient vectors from each subset should be weighted. It is not computationally feasible to calculate the mean subset coefficient vector for larger problems, and thus we suggest an algorithm to find an approximation to the mean subset coefficient vector. In a comprehensive Monte Carlo simulation study...

  17. The effect of molybdenum addition on SCC susceptibility of stainless steels in oxygenated high temperature water

    International Nuclear Information System (INIS)

    Akashi, Masatsune; Kawamoto, Teruaki

    1978-01-01

    The effect of molybdenum addition on the SCC susceptibility of sensitized stainless steel in oxygenated high temperature water has been studied through the creviced bent beam SCC test (CBB test) and A262E intergranular corrosion test. The molybdenum addition improved the SCC susceptibility of sensitized stainless steels in oxygenated high temperature water not only by delaying the sensitization at lower temperatures but also by increasing the material resistance to the SCC under a given degree of sensitization. These laboratory test results reveal that the molybdenum addition is quite beneficial for improving the SCC susceptibility of stainless steel pipe weld joints in boiling water reactor environment. (auth.)

  18. Plant for producing an oxygen-containing additive as an ecologically beneficial component for liquid motor fuels

    Science.gov (United States)

    Siryk, Yury Paul; Balytski, Ivan Peter; Korolyov, Volodymyr George; Klishyn, Olexiy Nick; Lnianiy, Vitaly Nick; Lyakh, Yury Alex; Rogulin, Victor Valery

    2013-04-30

    A plant for producing an oxygen-containing additive for liquid motor fuels comprises an anaerobic fermentation vessel, a gasholder, a system for removal of sulphuretted hydrogen, and a hotwell. The plant further comprises an aerobic fermentation vessel, a device for liquid substance pumping, a device for liquid aeration with an oxygen-containing gas, a removal system of solid mass residue after fermentation, a gas distribution device; a device for heavy gases utilization; a device for ammonia adsorption by water; a liquid-gas mixer; a cavity mixer, a system that serves superficial active and dispersant matters and a cooler; all of these being connected to each other by pipelines. The technical result being the implementation of a process for producing an oxygen containing additive, which after being added to liquid motor fuels, provides an ecologically beneficial component for motor fuels by ensuring the stability of composition fuel properties during long-term storage.

  19. Extracorporeal membrane oxygenation: current clinical practice, coding, and reimbursement.

    Science.gov (United States)

    Schuerer, Douglas J E; Kolovos, Nikoleta S; Boyd, Kayla V; Coopersmith, Craig M

    2008-07-01

    Extracorporeal membrane oxygenation (ECMO) is a technique for providing life support for patients experiencing both pulmonary and cardiac failure by maintaining oxygenation and perfusion until native organ function is restored. ECMO is used routinely at many specialized hospitals for infants and less commonly for children with respiratory or cardiac failure from a variety of causes. Its usage is more controversial in adults, but select medical centers have reported favorable findings in patients with ARDS and other causes of severe pulmonary failure. ECMO is also rarely used as a rescue therapy in a small subset of adult patients with cardiac failure. This article will review the current uses and techniques of ECMO in the critical care setting as well as the evidence supporting its usage. In addition, current practice management related to coding and reimbursement for this intensive therapy will be discussed.

  20. Effects of Dissolved Oxygen Concentration and Iron Addition on Immediate-early Gene Expression of Magnetospirillum gryphiswaldense MSR-1

    DEFF Research Database (Denmark)

    Zhuang, Shiwen; Anyaogu, Diana Chinyere; Kasama, Takeshi

    2017-01-01

    in cultures at 0.5% O2 compared to those at higher oxygen tensions. Moreover, expression of katG (catalase-peroxidase gene) and feoB2 (ferrous transport protein B2 gene) was reduced markedly by iron addition, regardless of oxygen conditions. The data provides a greater understanding of molecular response...

  1. A Genetic Algorithm for Selection of Fixed-Size Subsets with Application to Design Problems

    Directory of Open Access Journals (Sweden)

    Mark A. Wolters

    2015-11-01

    Full Text Available The R function kofnGA conducts a genetic algorithm search for the best subset of k items from a set of n alternatives, given an objective function that measures the quality of a subset. The function fills a gap in the presently available subset selection software, which typically searches over a range of subset sizes, restricts the types of objective functions considered, or does not include freely available code. The new function is demonstrated on two types of problem where a fixed-size subset search is desirable: design of environmental monitoring networks, and D-optimal design of experiments. Additionally, the performance is evaluated on a class of constructed test problems with a novel design that is interesting in its own right.

  2. Sub-sets of cancer stem cells differ intrinsically in their patterns of oxygen metabolism.

    Directory of Open Access Journals (Sweden)

    Luke Gammon

    Full Text Available The glycolytic response of hypoxic cells is primarily mediated by the hypoxia inducible factor alpha (HIF-1α but even in the presence of abundant oxygen tumours typically show high rates of glycolysis. Higher levels of HIF-1α in tumours are associated with a poorer prognosis and up-regulation of markers of epithelial mesenchymal transition (EMT due to HIF-1α actions. We have recently shown that EMT occurs within the CD44(high cancer stem cell (CSC fraction and that epithelial and EMT CSCs are distinguished by high and low ESA expression, respectively. We here show that hypoxia induces a marked shift of the CSC fraction towards EMT leading to altered cell morphology, an increased proportion of CD44(high/ESA(low cells, patterns of gene expression typical of EMT, and enhanced sphere-forming ability. The size of EMT fractions returned to control levels in normoxia indicating a reversible process. Surprisingly, however, even under normoxic conditions a fraction of EMT CSCs was present and maintained high levels of HIF-1α, apparently due to actions of cytokines such as TNFα. Functionally, this EMT CSC fraction showed decreased mitochondrial mass and membrane potential, consumed far less oxygen per cell, and produced markedly reduced levels of reactive oxygen species (ROS. These differences in the patterns of oxygen metabolism of sub-fractions of tumour cells provide an explanation for the general therapeutic resistance of CSCs and for the even greater resistance of EMT CSCs. They also identify potential mechanisms for manipulation of CSCs.

  3. A Feature Subset Selection Method Based On High-Dimensional Mutual Information

    Directory of Open Access Journals (Sweden)

    Chee Keong Kwoh

    2011-04-01

    Full Text Available Feature selection is an important step in building accurate classifiers and provides better understanding of the data sets. In this paper, we propose a feature subset selection method based on high-dimensional mutual information. We also propose to use the entropy of the class attribute as a criterion to determine the appropriate subset of features when building classifiers. We prove that if the mutual information between a feature set X and the class attribute Y equals to the entropy of Y , then X is a Markov Blanket of Y . We show that in some cases, it is infeasible to approximate the high-dimensional mutual information with algebraic combinations of pairwise mutual information in any forms. In addition, the exhaustive searches of all combinations of features are prerequisite for finding the optimal feature subsets for classifying these kinds of data sets. We show that our approach outperforms existing filter feature subset selection methods for most of the 24 selected benchmark data sets.

  4. Polymer growth rate in a wire chamber with oxygen, water, or alcohol gas additives

    International Nuclear Information System (INIS)

    Boyarski, Adam M.

    2009-01-01

    The rate of polymer growth on wires was measured in a wire chamber while the chamber was aged initially with helium:isobutane (80:20) gas, and then with either oxygen, water, or alcohol added to the gas. At the completion of the aging process for each gas mixture, the carbon content on the wires was measured in a scanning electron microscope/energy dispersive X-ray (SEM/EDX) instrument. The same physical wires were used in all the gas mixtures, allowing measurement of polymer build-up or polymer depletion by each gas additive. It is found that the rate of polymer growth is not changed by the presence of oxygen, water, or alcohol. Conjecture that oxygen reduces breakdown by removing polymer deposits on field wires is negated by these measurements. Instead, it appears that the reduced breakdown is due to lower resistance in the polymer from oxygen ions being transported into the polymer. It is also observed that field wires bombarded by the electrons in the SEM and then placed back into the chamber show an abundance of single electrons being emitted, indicating that electron charge is trapped in the polymer layer and that a high electric field is necessary to remove the charge.

  5. Subset Selection by Local Convex Approximation

    DEFF Research Database (Denmark)

    Øjelund, Henrik; Sadegh, Payman; Madsen, Henrik

    1999-01-01

    This paper concerns selection of the optimal subset of variables in a lenear regression setting. The posed problem is combinatiorial and the globally best subset can only be found in exponential time. We define a cost function for the subset selection problem by adding the penalty term to the usual...... of the subset selection problem so as to guarantee positive definiteness of the Hessian term, hence avoiding numerical instability. The backward Elemination type algorithm attempts to improve the results upon termination of the modified Newton-Raphson search by sing the current solution as an initial guess...

  6. Unsupervised Feature Subset Selection

    DEFF Research Database (Denmark)

    Søndberg-Madsen, Nicolaj; Thomsen, C.; Pena, Jose

    2003-01-01

    This paper studies filter and hybrid filter-wrapper feature subset selection for unsupervised learning (data clustering). We constrain the search for the best feature subset by scoring the dependence of every feature on the rest of the features, conjecturing that these scores discriminate some ir...... irrelevant features. We report experimental results on artificial and real data for unsupervised learning of naive Bayes models. Both the filter and hybrid approaches perform satisfactorily....

  7. Effectiveness of oxygen enriched hydrogen-HHO gas addition on DI diesel engine performance, emission and combustion characteristics

    Directory of Open Access Journals (Sweden)

    Premkartikkumar S.R.

    2014-01-01

    Full Text Available Nowadays, more researches focus on protecting the environment. Present investigation concern with the effectiveness of Oxygen Enriched hydrogen- HHO gas addition on performance, emission and combustion characteristics of a DI diesel engine. Here the Oxygen Enriched hydrogen-HHO gas was produced by the process of water electrolysis. When potential difference is applied across the anode and cathode electrodes of the electrolyzer, water is transmuted into Oxygen Enriched hydrogen-HHO gas. The produced gas was aspirated into the cylinder along with intake air at the flow rates of 1 lpm and 3.3 lpm. The results show that when Oxygen Enriched hydrogen-HHO gas was inducted, the brake thermal efficiency of the engine increased by 11.06%, Carbon monoxide decreased by 15.38%, Unburned hydrocarbon decreased by 18.18%, Carbon dioxide increased by 6.06%, however, the NOX emission increased by 11.19%.

  8. Massive two-loop Bhabha scattering - the factorizable subset

    International Nuclear Information System (INIS)

    Fleischer, J.; Tarasov, O.V.; Werthenbach, A.

    2002-11-01

    The experimental precision that will be reached at the next generation of colliders makes it indispensable to improve theoretical predictions significantly. Bhabha scattering (e + e - → e + e - ) is one of the prime processes calling for a better theoretical precision, in particular for non-zero electron masses. We present a first subset of the full two-loop calculation, namely the factorizable subset. Our calculation is based on DIANA. We reduce tensor integrals to scalar integrals in shifted (increased) dimensions and additional powers of various propagators, so-called dots-on-lines. Recurrence relations remove those dots-on-lines as well as genuine dots-on-lines (originating from mass renormalization) and reduce the dimension of the integrals to the generic d=4-2ε dimensions. The resulting master integrals have to be expanded to O(ε) to ensure proper treatment of all finite terms. (orig.)

  9. Determination of oxygen in ternary uranium oxides by a gravimetric alkaline earth addition method

    International Nuclear Information System (INIS)

    Fujino, T.; Tagawa, H.

    1979-01-01

    The applicability of a gravimetric method based on alkaline earth metal addition for the determination of oxygen in ternary uranium oxides of the tupe M-U-O (M=La, Ce and Th) is described. The oxide sample is mixed with MgO or Basub(2.8)UOsub(5.8) and heated in air under suitable conditions. Because uranium is completely oxidized to the hexavalent state during the reaction, oxygen can be determined from the weight change. Oxygen in Lasub(y)Usub(1-y)Osub(2+x) is determined up to y = 0.8 with a standard deviation for x of +- 0.006 with MgO. For Thsub(y)Usub(1-y)Osub(2+x) the value of x is determined with Basub(2.8)UOsub(5.8) with a standard deviation of +- 0.01 at y = 0.8. For Cesub(y)Usub(1-y)Osub(2+x), the method can be applied only for low cerium concentrations where y = 0-0.2; the value for x with Basub(2.8)UOsub(5.8) at y = 0.2 showed a standard deviation of +- 0.002. (Auth.)

  10. MODIS/Aqua Atmosphere Aeronet Subsetting Product

    Data.gov (United States)

    National Aeronautics and Space Administration — The MODIS/Aqua Atmosphere Aeronet Subsetting Product (MYDARNSS) consists of MODIS Atmosphere and Ancillary Products subsets that are generated over a number of...

  11. Subset selection in regression

    CERN Document Server

    Miller, Alan

    2002-01-01

    Originally published in 1990, the first edition of Subset Selection in Regression filled a significant gap in the literature, and its critical and popular success has continued for more than a decade. Thoroughly revised to reflect progress in theory, methods, and computing power, the second edition promises to continue that tradition. The author has thoroughly updated each chapter, incorporated new material on recent developments, and included more examples and references. New in the Second Edition:A separate chapter on Bayesian methodsComplete revision of the chapter on estimationA major example from the field of near infrared spectroscopyMore emphasis on cross-validationGreater focus on bootstrappingStochastic algorithms for finding good subsets from large numbers of predictors when an exhaustive search is not feasible Software available on the Internet for implementing many of the algorithms presentedMore examplesSubset Selection in Regression, Second Edition remains dedicated to the techniques for fitting...

  12. On subset selection from Logistic populations

    NARCIS (Netherlands)

    Laan, van der P.

    1990-01-01

    Some distributional results are derived for subset selection from Logistic populations, differing only in their location parameter. The probability of correct selection is determined. Exact and numerical results concerning the expected subset size are presented.

  13. Effective utilization of B20 blend with diethyl ether and ethanol as oxygenated additives

    Directory of Open Access Journals (Sweden)

    Upadrasta-Satya Vara-Prasad

    2011-01-01

    Full Text Available In the recent times' fatty acid methyl ester popularly called as biodiesel has become more prominent alternate fuel for compression ignition engines based on a single fuel concept. Since, use of neat biodiesel on a large scale is raising certain difficulties and is being adopted in a blended form with petro-diesel fuel and B20 blend has become standardized. However, the HC and NOx emissions of B20 are still on the higher side. Present work aims at experimental evaluation of a single cylinder water-cooled diesel engine by adopting various proportions of ethanol and diethyl ether blends in order to improve performance and emission characteristics of B20 blend. Besides employing different amounts of ethanol and diethyl ether, simultaneous influence of injector nozzle hole size and fuel injection pressure are also investigated to arrive at an optimum configuration. Brake specific fuel consumption and hydrocarbon emissions values are lower with B20 and DEE 5 whereas B20 with DEE15 yielded lower NOx emissions. It is observed that addition of oxygenates have improved the combustion process and lower emissions are obtained. The present investigation revealed that blends with oxygenated additives having higher Cetane rating are superior to neat blend.

  14. Selective effects of alpha interferon on human T-lymphocyte subsets during mixed lymphocyte cultures

    DEFF Research Database (Denmark)

    Hokland, M; Hokland, P; Heron, I

    1983-01-01

    Mixed lymphocyte reaction (MLR) cultures of human lymphocyte subsets with or without the addition of physiological doses of human alpha interferon (IFN-alpha) were compared with respect to surface marker phenotypes and proliferative capacities of the responder cells. A selective depression on the T...... T4 cells and decreased numbers of T4 cells harvested from IFN MLRs (days 5-6 of culture). In contrast, it was shown that the T8 (cytotoxic/suppressor) subset in MLRs was either not affected or slightly stimulated by the addition of IFN. The depression of the T4 cells by IFN was accompanied...... by a decrease in the number of activated T cells expressing Ia antigens. On the other hand, IFN MLRs contained greater numbers of cells expressing the T10 differentiation antigen. In experiments with purified T-cell subsets the IFN effect was exerted directly on the T4 cells and not mediated by either T8...

  15. On Maximal Non-Disjoint Families of Subsets

    Directory of Open Access Journals (Sweden)

    Yu. A. Zuev

    2017-01-01

    Full Text Available The paper studies maximal non-disjoint families of subsets of a finite set. Non-disjointness means that any two subsets of a family have a nonempty intersection. The maximality is expressed by the fact that adding a new subset to the family cannot increase its power without violating a non-disjointness condition. Studying the properties of such families is an important section of the extreme theory of sets. Along with purely combinatorial interest, the problems considered here play an important role in informatics, anti-noise coding, and cryptography.In 1961 this problem saw the light of day in the Erdos, Ko and Rado paper, which established a maximum power of the non-disjoint family of subsets of equal power. In 1974 the Erdos and Claytman publication estimated the number of maximal non-disjoint families of subsets without involving the equality of their power. These authors failed to establish an asymptotics of the logarithm of the number of such families when the power of a basic finite set tends to infinity. However, they suggested such an asymptotics as a hypothesis. A.D. Korshunov in two publications in 2003 and 2005 established the asymptotics for the number of non-disjoint families of the subsets of arbitrary powers without maximality condition of these families.The basis for the approach used in the paper to study the families of subsets is their description in the language of Boolean functions. A one-to-one correspondence between a family of subsets and a Boolean function is established by the fact that the characteristic vectors of subsets of a family are considered to be the unit sets of a Boolean function. The main theoretical result of the paper is that the maximal non-disjoint families are in one-to-one correspondence with the monotonic self-dual Boolean functions. When estimating the number of maximal non-disjoint families, this allowed us to use the result of A.A. Sapozhenko, who established the asymptotics of the number of the

  16. Subset-row inequalities applied to the vehicle routing problem with time windows

    DEFF Research Database (Denmark)

    Jepsen, Mads Kehlet; Petersen, Bjørn; Spoorendonk, Simon

    2008-01-01

    constraints as the pricing problem. We introduce the subset-row inequalities, which are Chvatal-Gomory rank-1 cuts based on a subset of the constraints in the master problem. Applying a subset-row inequality in the master problem increases the complexity of the label-setting algorithm used to solve......This paper presents a branch-and-cut-and-price algorithm for the vehicle-routing problem with time windows. The standard Dantzig-Wolfe decomposition of the arc flow formulation leads to a set-partitioning problem as the master problem and an elementary shortest-path problem with resource...... the pricing problem because an additional resource is added for each inequality. We propose a modified dominance criterion that makes it possible to dominate more labels by exploiting the step-like structure of the objective function of the pricing problem. Computational experiments have been performed...

  17. Efficient Secure Multiparty Subset Computation

    Directory of Open Access Journals (Sweden)

    Sufang Zhou

    2017-01-01

    Full Text Available Secure subset problem is important in secure multiparty computation, which is a vital field in cryptography. Most of the existing protocols for this problem can only keep the elements of one set private, while leaking the elements of the other set. In other words, they cannot solve the secure subset problem perfectly. While a few studies have addressed actual secure subsets, these protocols were mainly based on the oblivious polynomial evaluations with inefficient computation. In this study, we first design an efficient secure subset protocol for sets whose elements are drawn from a known set based on a new encoding method and homomorphic encryption scheme. If the elements of the sets are taken from a large domain, the existing protocol is inefficient. Using the Bloom filter and homomorphic encryption scheme, we further present an efficient protocol with linear computational complexity in the cardinality of the large set, and this is considered to be practical for inputs consisting of a large number of data. However, the second protocol that we design may yield a false positive. This probability can be rapidly decreased by reexecuting the protocol with different hash functions. Furthermore, we present the experimental performance analyses of these protocols.

  18. Additive preservers of the ascent, descent and related subsets

    Czech Academy of Sciences Publication Activity Database

    Mbekhta, M.; Müller, Vladimír; Oudghiri, M.

    2014-01-01

    Roč. 71, č. 1 (2014), s. 63-83 ISSN 0379-4024 R&D Projects: GA ČR GA201/09/0473; GA AV ČR IAA100190903 Institutional support: RVO:67985840 Keywords : additive preservers * ascent * descent Subject RIV: BA - General Mathematics Impact factor: 0.550, year: 2014 http://www.mathjournals.org/jot/2014-071-001/2014-071-001-004.html

  19. Oxygen and tissue culture affect placental gene expression.

    Science.gov (United States)

    Brew, O; Sullivan, M H F

    2017-07-01

    Placental explant culture is an important model for studying placental development and functions. We investigated the differences in placental gene expression in response to tissue culture, atmospheric and physiologic oxygen concentrations. Placental explants were collected from normal term (38-39 weeks of gestation) placentae with no previous uterine contractile activity. Placental transcriptomic expressions were evaluated with GeneChip ® Human Genome U133 Plus 2.0 arrays (Affymetrix). We uncovered sub-sets of genes that regulate response to stress, induction of apoptosis programmed cell death, mis-regulation of cell growth, proliferation, cell morphogenesis, tissue viability, and protection from apoptosis in cultured placental explants. We also identified a sub-set of genes with highly unstable pattern of expression after exposure to tissue culture. Tissue culture irrespective of oxygen concentration induced dichotomous increase in significant gene expression and increased enrichment of significant pathways and transcription factor targets (TFTs) including HIF1A. The effect was exacerbated by culture at atmospheric oxygen concentration, where further up-regulation of TFTs including PPARA, CEBPD, HOXA9 and down-regulated TFTs such as JUND/FOS suggest intrinsic heightened key biological and metabolic mechanisms such as glucose use, lipid biosynthesis, protein metabolism; apoptosis, inflammatory responses; and diminished trophoblast proliferation, differentiation, invasion, regeneration, and viability. These findings demonstrate that gene expression patterns differ between pre-culture and cultured explants, and the gene expression of explants cultured at atmospheric oxygen concentration favours stressed, pro-inflammatory and increased apoptotic transcriptomic response. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Role of distinct CD4(+) T helper subset in pathogenesis of oral lichen planus.

    Science.gov (United States)

    Wang, Hui; Zhang, Dunfang; Han, Qi; Zhao, Xin; Zeng, Xin; Xu, Yi; Sun, Zheng; Chen, Qianming

    2016-07-01

    Oral lichen planus (OLP) is one of the most common chronic inflammatory oral mucosal diseases with T-cell-mediated immune pathogenesis. In subepithelial and lamina propria of OLP local lesions, the presence of CD4(+) T helper (CD4(+) Th) cells appeared as the major lymphocytes. These CD4(+) T lymphocytes can differentiate into distinct Th cell types such as Th1, Th2, Treg, Th17, Th22, Th9, and Tfh within the context of certain cytokines environment. Growing evidence indicated that Th1/Th2 imbalance may greatly participate into the cytokine network of OLP immunopathology. In addition, Th1/Th2 imbalance can be regulated by the Treg subset and also greatly influenced by the emerging novel CD4(+) Th subset Th17. Furthermore, the presence of novel subsets Th22, Th9 and Tfh in OLP patients is yet to be clarified. All these Th subsets and their specific cytokines may play a critical role in determining the character, extent and duration of immune responses in OLP pathogenesis. Therefore, we review the roles of distinct CD4(+) Th subsets and their signature cytokines in determining disease severity and susceptibility of OLP and also reveal the novel therapeutic strategies based on T lymphocytes subsets in OLP treatment. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  1. Dissolved oxygen analysis for hydropower additions on the Illinois River

    International Nuclear Information System (INIS)

    Sundquist, M.J.; Elver, S.A.

    1993-01-01

    The Illinois Waterway is comprised of a system of eight locks along the Illinois River, the Des Plaines River, and the Chicago Sanitary Ship Canal which allow commercial barge traffic between the Mississippi River and Lake Michigan at the City of Chicago. Opportunities for production of hydroelectric power is present at several of these lock and dams. This paper presents the field study and computer simulation conducted to determine the feasibility of constructing hydroelectric powerhouses on two of these lock and dams. So as not to degrade recent improvements to water quality, the Federal Energy Regulatory Commission (FERC), in issuing the construction and operating licenses for these two hydroelectric facilities, requires the hydropower additions to not reduce the dissolved oxygen (D.O.) level downstream of the hydroelectric facilities below 6 parts per million (ppm). Presently, the waterway discharge passes through taintor gates at both of these lock and dam facilities which creates aeration. The addition of hydroelectric powerhouses would divert water from these spillways through generation equipment; consequently, the spillway aeration would not occur. The purpose of the study was to determine the amount of power generation from these facilities, given the existing waterway water quality and the FERC D.O. criteria. A computer simulation generation analysis was conducted to provide a database of the waterway water quality. A four-month extensive field collection survey was conducted over the 63 kilometer (39 mile) reach of the waterway which comprises the two downstream pools of the Brandon Road and Dresden Island projects, and 3 kilometers (2 miles) upstream of the Brandon Road Project. The analysis revealed that the hydroelectric additions were economically feasible and are an example of how the benefits of hydroelectric development can be balanced with environmental concerns

  2. ';Best' Practices for Aggregating Subset Results from Archived Datasets

    Science.gov (United States)

    Baskin, W. E.; Perez, J.

    2013-12-01

    In response to the exponential growth in science data analysis and visualization capabilities Data Centers have been developing new delivery mechanisms to package and deliver large volumes of aggregated subsets of archived data. New standards are evolving to help data providers and application programmers deal with growing needs of the science community. These standards evolve from the best practices gleaned from new products and capabilities. The NASA Atmospheric Sciences Data Center (ASDC) has developed and deployed production provider-specific search and subset web applications for the CALIPSO, CERES, TES, and MOPITT missions. This presentation explores several use cases that leverage aggregated subset results and examines the standards and formats ASDC developers applied to the delivered files as well as the implementation strategies for subsetting and processing the aggregated products. The following topics will be addressed: - Applications of NetCDF CF conventions to aggregated level 2 satellite subsets - Data-Provider-Specific format requirements vs. generalized standards - Organization of the file structure of aggregated NetCDF subset output - Global Attributes of individual subsetted files vs. aggregated results - Specific applications and framework used for subsetting and delivering derivative data files

  3. Different Subsets of T Cells, Memory, Effector Functions, and CAR-T Immunotherapy.

    Science.gov (United States)

    Golubovskaya, Vita; Wu, Lijun

    2016-03-15

    This review is focused on different subsets of T cells: CD4 and CD8, memory and effector functions, and their role in CAR-T therapy--a cellular adoptive immunotherapy with T cells expressing chimeric antigen receptor. The CAR-T cells recognize tumor antigens and induce cytotoxic activities against tumor cells. Recently, differences in T cell functions and the role of memory and effector T cells were shown to be important in CAR-T cell immunotherapy. The CD4⁺ subsets (Th1, Th2, Th9, Th17, Th22, Treg, and Tfh) and CD8⁺ memory and effector subsets differ in extra-cellular (CD25, CD45RO, CD45RA, CCR-7, L-Selectin [CD62L], etc.); intracellular markers (FOXP3); epigenetic and genetic programs; and metabolic pathways (catabolic or anabolic); and these differences can be modulated to improve CAR-T therapy. In addition, CD4⁺ Treg cells suppress the efficacy of CAR-T cell therapy, and different approaches to overcome this suppression are discussed in this review. Thus, next-generation CAR-T immunotherapy can be improved, based on our knowledge of T cell subsets functions, differentiation, proliferation, and signaling pathways to generate more active CAR-T cells against tumors.

  4. Different Subsets of T Cells, Memory, Effector Functions, and CAR-T Immunotherapy

    Directory of Open Access Journals (Sweden)

    Vita Golubovskaya

    2016-03-01

    Full Text Available This review is focused on different subsets of T cells: CD4 and CD8, memory and effector functions, and their role in CAR-T therapy––a cellular adoptive immunotherapy with T cells expressing chimeric antigen receptor. The CAR-T cells recognize tumor antigens and induce cytotoxic activities against tumor cells. Recently, differences in T cell functions and the role of memory and effector T cells were shown to be important in CAR-T cell immunotherapy. The CD4+ subsets (Th1, Th2, Th9, Th17, Th22, Treg, and Tfh and CD8+ memory and effector subsets differ in extra-cellular (CD25, CD45RO, CD45RA, CCR-7, L-Selectin [CD62L], etc.; intracellular markers (FOXP3; epigenetic and genetic programs; and metabolic pathways (catabolic or anabolic; and these differences can be modulated to improve CAR-T therapy. In addition, CD4+ Treg cells suppress the efficacy of CAR-T cell therapy, and different approaches to overcome this suppression are discussed in this review. Thus, next-generation CAR-T immunotherapy can be improved, based on our knowledge of T cell subsets functions, differentiation, proliferation, and signaling pathways to generate more active CAR-T cells against tumors.

  5. Photon Doppler Velocimeter to Measure Entrained Additive Manufactured Bulk Metal Powders in Hot Subsonic and Supersonic Oxygen Gas

    Science.gov (United States)

    Tylka, Jonathan

    2016-01-01

    Parts produced by additive manufacturing, particularly selective laser melting (SLM), have been shown to silt metal particulate even after undergoing stringent precision aerospace cleaning processes (Lowrey 2016). As printed parts are used in oxygen systems with increased pressures, temperatures, and gas velocity, the risk of ignition by particle impact, the most common direct ignition source of metals in oxygen, substantially increases. The White Sands Test Facility (WSTF), in collaboration with Marshall Space Flight Center (MSFC), desires to test the ignitability of SLM metals by particle impact in heated oxygen. The existing test systems rely on gas velocity calculations to infer particle velocity in both subsonic and supersonic particle impact systems. Until now, it was not possible to directly measure particle velocity. To increase the fidelity of planned SLM ignition studies, it is necessary to validate that the Photon Doppler Velocimetry(PDV) test system can accurately measure particle velocity.

  6. Variable and subset selection in PLS regression

    DEFF Research Database (Denmark)

    Høskuldsson, Agnar

    2001-01-01

    The purpose of this paper is to present some useful methods for introductory analysis of variables and subsets in relation to PLS regression. We present here methods that are efficient in finding the appropriate variables or subset to use in the PLS regression. The general conclusion...... is that variable selection is important for successful analysis of chemometric data. An important aspect of the results presented is that lack of variable selection can spoil the PLS regression, and that cross-validation measures using a test set can show larger variation, when we use different subsets of X, than...

  7. Towards Qualifiable Code Generation from a Clocked Synchronous Subset of Modelica

    Directory of Open Access Journals (Sweden)

    Bernhard Thiele

    2015-01-01

    Full Text Available So far no qualifiable automatic code generators (ACGs are available for Modelica. Hence, digital control applications can be modeled and simulated in Modelica, but require tedious additional efforts (e.g., manual reprogramming to produce qualifiable target system production code. In order to more fully leverage the potential of a model-based development (MBD process in Modelica, a qualifiable automatic code generator is needed. Typical Modelica code generation is a fairly complex process which imposes a huge development burden to any efforts of tool qualification. This work aims at mapping a Modelica subset for digital control function development to a well-understood synchronous data-flow kernel language. This kernel language allows to resort to established compilation techniques for data-flow languages which are understood enough to be accepted by certification authorities. The mapping is established by providing a translational semantics from the Modelica subset to the synchronous data-flow kernel language. However, this translation turned out to be more intricate than initially expected and has given rise to several interesting issues that require suitable design decisions regarding the mapping and the language subset.

  8. Effect of Ce2O3, La2O3 and ZnO additives on the oxygenates conversion into liquid hydrocarbons

    Science.gov (United States)

    Kachalov, V. V.; Lavrenov, V. A.; Lishchiner, I. I.; Malova, O. V.; Tarasov, A. L.; Zaichenko, V. M.

    2018-01-01

    A selective modifying effect of cerium, magnesium and zinc oxide additives on the activity and the selectivity of a pentasil group zeolite catalyst in the reaction of conversion of oxygenates (methanol and dimethyl ether) to liquid hydrocarbons was found. It was found that zinc oxide contributes to the stable operation of the zeolite catalyst in the conversion of oxygenates in the synthesis gas stream and leads to the production of gasolines with low durene content (not more than 6.1 wt%). The obtained results demonstrate the rationale for producing hydrocarbons from synthesis gas without the stage of oxygenate separation with their subsequent conversion to synthetic gasoline.

  9. OXYGEN MANAGEMENT DURING ALCOHOLIC FERMENTATION

    OpenAIRE

    MOENNE VARGAS, MARÍA ISABE

    2013-01-01

    Oxygen additions are a common practice in winemaking, as oxygen has a positive effect in fermentative kinetics, biomass synthesis and improvement of color, structure and :flavor in treated wines. However, most oxygen additions are carried out heuristically through pump-over operations solely on a know-how basis, which is difficult to manage in terms of the exact quantity of oxygen transferred to the fermenting must. It is important to estímate the amount of oxygen added because...

  10. Solubility of oxygen in liquid sodium: effect on interpretation of corrosion data

    International Nuclear Information System (INIS)

    Claxton, K.T.

    1976-01-01

    No solubility correlation relating the equilibrium oxygen concentration with the sodium saturation temperature has yet been derived which has gained general acceptance. A statistical analysis of all the available data which directly or indirectly may be taken as representing a measurement of solubility has been made. The results indicate that a real and seemingly permanent difference is apparent between the assumed equilibrium levels of oxygen measured at different saturation temperatures as reported by UK and US workers. Data analysis procedures producing sub-sets of culled data which are then used to derive a compromise solubility function are considered less than adequate. It is considered preferable and more realistic to distinguish data sub-sets by the analytical technique employed. The established vacuum distillation method is shown to yield results differing among themselves by up to a factor of four at cold trap temperatures of relevance to fast reactor operation. The vanadium wire and electrochemical cell techniques are shown to give the lowest solubility values. Appropriate factors relating UK oxygen levels to values derived from alternative methods are presented. The divergent positions prevailing for oxygen-in-sodium analysis can lead to apparent anomalies when comparisons of corrosion rates from different sources have to be made. It is shown that this situation is, in part, apparently resolved by effecting comparisons at the equivalent cold trap temperature instead of the equivalent oxygen level. It is recognised that the approach presumes equilibrium of the oxygen in the sodium with the cold trap and reference is made to alternative ''sinks'' for oxygen. It is demonstrated, by comparison of a number of recommended and observed corrosion rates from US and European sources, that, in spite of the above and other qualifications, the approach is reasonable

  11. T-Cell Subsets Predict Mortality in Malnourished Zambian Adults Initiating Antiretroviral Therapy.

    Directory of Open Access Journals (Sweden)

    Caroline C Chisenga

    Full Text Available To estimate the prognostic value of T-cell subsets in Zambian patients initiating antiretroviral therapy (ART, and to assess the impact of a nutritional intervention on T-cell subsets.This was a sub-study of a randomised clinical trial of a nutritional intervention for malnourished adults initiating ART. Participants in a randomised controlled trial (NUSTART trial were enrolled between April and December 2012. Participants received lipid-based nutritional supplement either with or without additional vitamins and minerals. Immunophenotyping was undertaken at baseline and, in survivors, after 12 weeks of ART to characterize T-cell subsets using the markers CD3, CD4, CD8, CD45RA, CCR7, CD28, CD57, CD31, α4β7, Ki67, CD25 and HLA-DR. Univariate and multivariate survival analysis was performed, and responses to treatment were analysed using the Wicoxon rank-sum test.Among 181 adults, 36 (20% died by 12 weeks after starting ART. In univariate analysis, patients who died had fewer proliferating, more naïve and fewer gut homing CD4+ T-cells compared to survivors; and more senescent and fewer proliferating CD8+ T-cells. In a multivariate Cox regression model high naïve CD4+, low proliferating CD4+, high senescent CD8+ and low proliferating CD8+ subsets were independently associated with increased risk of death. Recent CD4+ thymic emigrants increased less between recruitment and 12 weeks of ART in the intervention group compared to the control group.Specific CD4+ T-cell subsets are of considerable prognostic significance for patients initiating ART in Zambia, but only thymic output responded to this nutritional intervention.

  12. Subset-sum phase transitions and data compression

    Science.gov (United States)

    Merhav, Neri

    2011-09-01

    We propose a rigorous analysis approach for the subset-sum problem in the context of lossless data compression, where the phase transition of the subset-sum problem is directly related to the passage between ambiguous and non-ambiguous decompression, for a compression scheme that is based on specifying the sequence composition. The proposed analysis lends itself to straightforward extensions in several directions of interest, including non-binary alphabets, incorporation of side information at the decoder (Slepian-Wolf coding), and coding schemes based on multiple subset sums. It is also demonstrated that the proposed technique can be used to analyze the critical behavior in a more involved situation where the sequence composition is not specified by the encoder.

  13. Kinetics of irreversible thermal decomposition of dissociating nitrogen dioxide with nitrogen oxide or oxygen additions

    International Nuclear Information System (INIS)

    Gvozdev, A.A.

    1987-01-01

    The effect of NO or O 2 admixtures on kinetics of the irreversible thermal decomposition of nitrogen dioxide at temperatures 460-520 deg C and pressures 4-7 MPa has been studied. It follows from experimental data that the rate of N 2 O 4 formation reduces with the increase of partial pressure of oxygen or decrease of partial pressure of nitrogen oxide. The same regularity is seen for the rate of nitrogen formation. The rate constants of N 2 O formation in dissociating nitrogen tetroxide with oxygen or nitrogen oxide additions agree satisfactorily with previously published results, obtained in stoichiometric mixtures. The appreciable discrepancy at 520 deg C is bind with considerable degree of nitrogen oxide transformation which constitutes approximately 14%. It is determined that the kinetics of formation of the products of irreversible N 2 O and N 2 decomposition in stoichiometric and non-stoichiometric 2NO 2 ↔ 2NO+O 2 mixtures is described by identical 3NO → N 2 O+NO 2 and N 2 O+NO → N 2 +NO 2 reactions

  14. Data mining a small molecule drug screening representative subset from NIH PubChem.

    Science.gov (United States)

    Xie, Xiang-Qun; Chen, Jian-Zhong

    2008-03-01

    PubChem is a scientific showcase of the NIH Roadmap Initiatives. It is a compound repository created to facilitate information exchange and data sharing among the NIH Roadmap-funded Molecular Library Screening Center Network (MLSCN) and the scientific community. However, PubChem has more than 10 million records of compound information. It will be challenging to conduct a drug screening of the whole database of millions of compounds. Thus, the purpose of the present study was to develop a data mining cheminformatics approach in order to construct a representative and structure-diverse sublibrary from the large PubChem database. In this study, a new chemical diverse representative subset, rePubChem, was selected by whole-molecule chemistry-space matrix calculation using the cell-based partition algorithm. The representative subset was generated and was then subjected to evaluations by compound property analyses based on 1D and 2D molecular descriptors. The new subset was also examined and assessed for self-similarity analysis based on 2D molecular fingerprints in comparing with the source compound library. The new subset has a much smaller library size (540K compounds) with minimum similarity and redundancy without loss of the structural diversity and basic molecular properties of its parent library (5.3 million compounds). The new representative subset library generated could be a valuable structure-diverse compound resource for in silico virtual screening and in vitro HTS drug screening. In addition, the established subset generation method of using the combined cell-based chemistry-space partition metrics with pairwised 2D fingerprint-based similarity search approaches will also be important to a broad scientific community interested in acquiring structurally diverse compounds for efficient drug screening, building representative virtual combinatorial chemistry libraries for syntheses, and data mining large compound databases like the PubChem library in general.

  15. Density measures and additive property

    OpenAIRE

    Kunisada, Ryoichi

    2015-01-01

    We deal with finitely additive measures defined on all subsets of natural numbers which extend the asymptotic density (density measures). We consider a class of density measures which are constructed from free ultrafilters on natural numbers and study a certain additivity property of such density measures.

  16. Rates and products of degradation for MTBE and other oxygenate fuel additives in the subsurface environment

    International Nuclear Information System (INIS)

    Tratnyek, P.G.; Church, C.D.; Pankow, J.F.

    1995-01-01

    The recent realization that oxygenated fuel additives such as MTBE are becoming widely distributed groundwater contaminants has created a sudden and pressing demand for data on the processes that control their environmental fate. Explaining and predicting the subsequent environmental fate of these compounds is going to require extrapolations over long time frames that will be very sensitive to the quality of input data on each compound. To provide such data, they have initiated a systematic study of the pathways and kinetics of fuel oxygenate degradation under subsurface conditions. Batch experiments in simplified model systems are being performed to isolate specific processes that may contribute to MTBE degradation. A variety of degradation pathways can be envisioned that lead to t-butyl alcohol (TBA) as the primary or secondary product. However, experiments to date with a facultative iron reducing bacteria showed no evidence for TBA formation. Continuing experiments include mixed cultures from a range of aquifer materials representative of NAWQA study sites

  17. Oxygen in the critically ill: friend or foe?

    Science.gov (United States)

    Damiani, Elisa; Donati, Abele; Girardis, Massimo

    2018-04-01

    To examine the potential harmful effects of hyperoxia and summarize the results of most recent clinical studies evaluating oxygen therapy in critically ill patients. Excessive oxygen supplementation may have detrimental pulmonary and systemic effects because of enhanced oxidative stress and inflammation. Hyperoxia-induced lung injury includes altered surfactant protein composition, reduced mucociliary clearance and histological damage, resulting in atelectasis, reduced lung compliance and increased risk of infections. Hyperoxemia causes vasoconstriction, reduction in coronary blood flow and cardiac output and may alter microvascular perfusion. Observational studies showed a close relationship between hyperoxemia and increased mortality in several subsets of critically ill patients. In absence of hypoxemia, the routine use of oxygen therapy in patients with myocardial infarction, stroke, traumatic brain injury, cardiac arrest and sepsis, showed no benefit but rather it seems to be harmful. In patients admitted to intensive care unit, a conservative oxygen therapy aimed to maintain arterial oxygenation within physiological range has been proved to be well tolerated and may improve outcome. Liberal O2 use and unnecessary hyperoxia may be detrimental in critically ill patients. The current evidence supports the use of a conservative strategy in O2 therapy to avoid patient exposure to unnecessary hyperoxemia.

  18. Stochastic subset selection for learning with kernel machines.

    Science.gov (United States)

    Rhinelander, Jason; Liu, Xiaoping P

    2012-06-01

    Kernel machines have gained much popularity in applications of machine learning. Support vector machines (SVMs) are a subset of kernel machines and generalize well for classification, regression, and anomaly detection tasks. The training procedure for traditional SVMs involves solving a quadratic programming (QP) problem. The QP problem scales super linearly in computational effort with the number of training samples and is often used for the offline batch processing of data. Kernel machines operate by retaining a subset of observed data during training. The data vectors contained within this subset are referred to as support vectors (SVs). The work presented in this paper introduces a subset selection method for the use of kernel machines in online, changing environments. Our algorithm works by using a stochastic indexing technique when selecting a subset of SVs when computing the kernel expansion. The work described here is novel because it separates the selection of kernel basis functions from the training algorithm used. The subset selection algorithm presented here can be used in conjunction with any online training technique. It is important for online kernel machines to be computationally efficient due to the real-time requirements of online environments. Our algorithm is an important contribution because it scales linearly with the number of training samples and is compatible with current training techniques. Our algorithm outperforms standard techniques in terms of computational efficiency and provides increased recognition accuracy in our experiments. We provide results from experiments using both simulated and real-world data sets to verify our algorithm.

  19. Association Between Arterial Hyperoxia and Outcome in Subsets of Critical Illness: A Systematic Review, Meta-Analysis, and Meta-Regression of Cohort Studies.

    Science.gov (United States)

    Helmerhorst, Hendrik J F; Roos-Blom, Marie-José; van Westerloo, David J; de Jonge, Evert

    2015-07-01

    Oxygen is vital during critical illness, but hyperoxia may harm patients. Our aim was to systematically evaluate the methodology and findings of cohort studies investigating the effects of hyperoxia in critically ill adults. A meta-analysis and meta-regression analysis of cohort studies published between 2008 and 2015 was conducted. Electronic databases of MEDLINE, EMBASE, and Web of Science were systematically searched for the keywords hyperoxia and mortality or outcome. Publications assessing the effect of arterial hyperoxia on outcome in critically ill adults (≥ 18 yr) admitted to critical care units were eligible. We excluded studies in patients with chronic obstructive pulmonary disease, extracorporeal life support or hyperbaric oxygen therapy, and animal studies. Due to a lack of data, no studies dedicated to patients with acute lung injury, sepsis, shock, or multiple trauma could be included. Studies were included independent of admission diagnosis and definition of hyperoxia. The primary outcome measure was in-hospital mortality, and results were stratified for relevant subgroups (cardiac arrest, traumatic brain injury, stroke, post-cardiac surgery, and any mechanical ventilation). The effects of arterial oxygenation on functional outcome, long-term mortality, and discharge variables were studied as secondary outcomes. Twenty-four studies were included of which five studies were only for a subset of the analyses. Nineteen studies were pooled for meta-analyses and showed that arterial hyperoxia during admission increases hospital mortality: adjusted odds ratio, 1.21 (95% CI, 1.08-1.37) (p = 0.001). Functional outcome measures were diverse and generally showed a more favorable outcome for normoxia. In various subsets of critically ill patients, arterial hyperoxia was associated with poor hospital outcome. Considering the substantial heterogeneity of included studies and the lack of a clinical definition, more evidence is needed to provide optimal oxygen

  20. Solubility of Oxygen in Liquid Sodium and the Interpretation of Predictions for the Corrosion Rate of Stainless Steels in Liquid Sodium

    International Nuclear Information System (INIS)

    Claxton, K. T.

    1979-01-01

    A statistical analysis of all oxygen in sodium solubility data has been made. The results indicate a real difference. between levels of oxygen reported by UK und US workers. Analysis using sub-sets of culled data to derive a compromise solubility function are considered less than adequate. It is considered preferable and more realistic to distinguish data sub-sets by the analytical technique employed. The vacuum distillation method yields results differing amongst them selves by up to a factor of five at cold trap temperatures of relevance to fast reactor operation. The vanadium wire and electrochemical cell techniques give the lowest solubility values. (Author) 51 refs

  1. Development of a synchronous subset of AADL

    DEFF Research Database (Denmark)

    Filali, Mamoun; Lawall, Julia

    2010-01-01

    We study the definition and the mapping of an AADL subset: the so called synchronous subset. We show that the data port protocol used for delayed and immediate connections between periodic threads can be interpreted in a  synchronous way. In this paper, we formalize this interpretation and study ...... the development of its mapping such that the original synchronous semantics is preserved. For that purpose, we use refinements through the Event B method....

  2. Muon-oxygen bonding in V2O3

    International Nuclear Information System (INIS)

    Chan, K.C.B.; Lichti, R.L.; Boekema, C.

    1986-01-01

    A muon site search using calculated internal fields has been performed for V 2 O 3 , where purely dipolar fields allow a site determination free from covalent complications. The obtained sites are a subset of the Rodriguez and Bates sites found in α-Fe 2 O 3 and indicate muon oxygen bond formation. The sites missing at low temperatures are consistent with the vanadium pairing mechanism for the metal-to-insulator (corundum-to-monoclinic) phase transition. (orig.)

  3. 75 FR 739 - Use of Additional Portable Oxygen Concentrator Devices on Board Aircraft

    Science.gov (United States)

    2010-01-06

    ...;Prices of new books are listed in the first FEDERAL REGISTER issue of each #0;week. #0; #0; #0; #0;#0... approved by the Food and Drug Administration (FDA) reduce the risks typically associated with compressed... developed small portable oxygen concentrators (POC) that work by separating oxygen from nitrogen and other...

  4. Band Subset Selection for Hyperspectral Image Classification

    Directory of Open Access Journals (Sweden)

    Chunyan Yu

    2018-01-01

    Full Text Available This paper develops a new approach to band subset selection (BSS for hyperspectral image classification (HSIC which selects multiple bands simultaneously as a band subset, referred to as simultaneous multiple band selection (SMMBS, rather than one band at a time sequentially, referred to as sequential multiple band selection (SQMBS, as most traditional band selection methods do. In doing so, a criterion is particularly developed for BSS that can be used for HSIC. It is a linearly constrained minimum variance (LCMV derived from adaptive beamforming in array signal processing which can be used to model misclassification errors as the minimum variance. To avoid an exhaustive search for all possible band subsets, two numerical algorithms, referred to as sequential (SQ and successive (SC algorithms are also developed for LCMV-based SMMBS, called SQ LCMV-BSS and SC LCMV-BSS. Experimental results demonstrate that LCMV-based BSS has advantages over SQMBS.

  5. Characterization of a chromosome-specific chimpanzee alpha satellite subset: Evolutionary relationship to subsets on human chromosomes

    Energy Technology Data Exchange (ETDEWEB)

    Warburton, P.E.; Gosden, J.; Lawson, D. [Western General Hospital, Edinburgh (United Kingdom)] [and others

    1996-04-15

    Alpha satellite DNA is a tandemly repeated DNA family found at the centromeres of all primate chromosomes examined. The fundamental repeat units of alpha satellite DNA are diverged 169- to 172-bp monomers, often found to be organized in chromosome-specific higher-order repeat units. The chromosomes of human (Homo sapiens (HSA)), chimpanzee (Pan troglodytes (PTR) and Pan paniscus), and gorilla (Gorilla gorilla) share a remarkable similarity and synteny. It is of interest to ask if alpha satellite arrays at centromeres of homologous chromosomes between these species are closely related (evolving in an orthologous manner) or if the evolutionary processes that homogenize and spread these arrays within and between chromosomes result in nonorthologous evolution of arrays. By using PCR primers specific for human chromosome 17-specific alpha satellite DNA, we have amplified, cloned, and characterized a chromosome-specific subset from the PTR chimpanzee genome. Hybridization both on Southern blots and in situ as well as sequence analysis show that this subset is most closely related, as expected, to sequences on HSA 17. However, in situ hybridization reveals that this subset is not found on the homologous chromosome in chimpanzee (PTR 19), but instead on PTR 12, which is homologous to HSA 2p. 40 refs., 3 figs.

  6. Characterization of the myeloid-derived suppressor cell subset regulated by NK cells in malignant lymphoma.

    Science.gov (United States)

    Sato, Yusuke; Shimizu, Kanako; Shinga, Jun; Hidaka, Michihiro; Kawano, Fumio; Kakimi, Kazuhiro; Yamasaki, Satoru; Asakura, Miki; Fujii, Shin-Ichiro

    2015-03-01

    Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population with the ability to suppress immune responses and are currently classified into three distinct MDSC subsets: monocytic, granulocytic and non-monocytic, and non-granulocytic MDSCs. Although NK cells provide an important first-line defense against newly transformed cancer cells, it is unknown whether NK cells can regulate MDSC populations in the context of cancer. In this study, we initially found that the frequency of MDSCs in non-Hodgkin lymphoma (NHL) patients was increased and inversely correlated with that of NK cells, but not that of T cells. To investigate the regulation of MDSC subsets by NK cells, we used an EL4 murine lymphoma model and found the non-monocytic and non-granulocytic MDSC subset, i.e., Gr1 + CD11b + Ly6G med Ly6C med MDSC, is increased after NK cell depletion. The MDSC population that expresses MHC class II, CD80, CD124, and CCR2 is regulated mainly by CD27 + CD11b + NK cells. In addition, this MDSC subset produces some immunosuppressive cytokines, including IL-10 but not nitric oxide (NO) or arginase. We also examined two subsets of MDSCs (CD14 + HLA-DR - and CD14 - HLA-DR - MDSC) in NHL patients and found that higher IL-10-producing CD14 + HLA-DR - MDSC subset can be seen in lymphoma patients with reduced NK cell frequency in peripheral blood. Our analyses of MDSCs in this study may enable a better understanding of how MDSCs manipulate the tumor microenvironment and are regulated by NK cells in patients with lymphoma.

  7. Tachykinins stimulate a subset of mouse taste cells.

    Directory of Open Access Journals (Sweden)

    Jeff Grant

    Full Text Available The tachykinins substance P (SP and neurokinin A (NKA are present in nociceptive sensory fibers expressing transient receptor potential cation channel, subfamily V, member 1 (TRPV1. These fibers are found extensively in and around the taste buds of several species. Tachykinins are released from nociceptive fibers by irritants such as capsaicin, the active compound found in chili peppers commonly associated with the sensation of spiciness. Using real-time Ca(2+-imaging on isolated taste cells, it was observed that SP induces Ca(2+ -responses in a subset of taste cells at concentrations in the low nanomolar range. These responses were reversibly inhibited by blocking the SP receptor NK-1R. NKA also induced Ca(2+-responses in a subset of taste cells, but only at concentrations in the high nanomolar range. These responses were only partially inhibited by blocking the NKA receptor NK-2R, and were also inhibited by blocking NK-1R indicating that NKA is only active in taste cells at concentrations that activate both receptors. In addition, it was determined that tachykinin signaling in taste cells requires Ca(2+-release from endoplasmic reticulum stores. RT-PCR analysis further confirmed that mouse taste buds express NK-1R and NK-2R. Using Ca(2+-imaging and single cell RT-PCR, it was determined that the majority of tachykinin-responsive taste cells were Type I (Glial-like and umami-responsive Type II (Receptor cells. Importantly, stimulating NK-1R had an additive effect on Ca(2+ responses evoked by umami stimuli in Type II (Receptor cells. This data indicates that tachykinin release from nociceptive sensory fibers in and around taste buds may enhance umami and other taste modalities, providing a possible mechanism for the increased palatability of spicy foods.

  8. Density functional theory study the effects of oxygen-containing functional groups on oxygen molecules and oxygen atoms adsorbed on carbonaceous materials.

    Science.gov (United States)

    Qi, Xuejun; Song, Wenwu; Shi, Jianwei

    2017-01-01

    Density functional theory was used to study the effects of different types of oxygen-containing functional groups on the adsorption of oxygen molecules and single active oxygen atoms on carbonaceous materials. During gasification or combustion reactions of carbonaceous materials, oxygen-containing functional groups such as hydroxyl(-OH), carbonyl(-CO), quinone(-O), and carboxyl(-COOH) are often present on the edge of graphite and can affect graphite's chemical properties. When oxygen-containing functional groups appear on a graphite surface, the oxygen molecules are strongly adsorbed onto the surface to form a four-member ring structure. At the same time, the O-O bond is greatly weakened and easily broken. The adsorption energy value indicates that the adsorption of oxygen molecules changes from physisorption to chemisorption for oxygen-containing functional groups on the edge of a graphite surface. In addition, our results indicate that the adsorption energy depends on the type of oxygen-containing functional group. When a single active oxygen atom is adsorbed on the bridge site of graphite, it gives rise to a stable epoxy structure. Epoxy can cause deformation of the graphite lattice due to the transition of graphite from sp2 to sp3 after the addition of an oxygen atom. For quinone group on the edge of graphite, oxygen atoms react with carbon atoms to form the precursor of CO2. Similarly, the single active oxygen atoms of carbonyl groups can interact with edge carbon atoms to form the precursor of CO2. The results show that oxygen-containing functional groups on graphite surfaces enhance the activity of graphite, which promotes adsorption on the graphite surface.

  9. Theory and development of fluorescence-based optochemical oxygen sensors: oxygen optodes.

    Science.gov (United States)

    Opitz, N; Lübbers, D W

    1987-01-01

    As the preceding considerations concerning the physical and technical features of oxygen optodes have demonstrated, fluorescence-based optochemical oxygen sensors possess certain advantages and peculiarities compared to conventionally applied electrochemical sensors such as polarographic oxygen electrodes. First, in contrast to oxygen electrodes, oxygen measurements with oxygen optodes do not suffer from distortions caused by the reference electrodes. In addition, because of the polarographic process, platinum electrodes continuously consume oxygen, which falsifies the results, especially when small sample volumes or long-term measurements, or both, are involved, whereas the sensor layer of oxygen optodes must only be equilibrated. Moreover, the surface of the platinum wire has to be catalytically clean in order to obtain a plateau of the polarogram and, consequently, to achieve a low rest current at zero PO2. Unfortunately, the demand for catalytically clean platinum surfaces turns out to be rather critical, since surface contamination occurs even with membranized electrodes, resulting in the well-known phenomenon of "electrode poisoning." The question of the specificity of oxygen electrodes also must be considered. In this context, CO2 and halothane may interfere with oxygen measurements, whereas fluorescence quenching is unaffected by CO2 and halothane affects the measurements only slightly, depending on the special indicator used. Furthermore, because of the flow dependence, oxygen measurements with the oxygen electrode show a distinct "stirring effect" caused by the turbulence in front of the electrode, which disturbs the diffusion field. Because of the completely different physical principle of fluorescence optical sensors, such influences are not observed with oxygen optodes. In addition, isolation and shielding of electrical circuits found in electrodes are not necessary for optodes. Furthermore, the sensitivity of oxygen optodes can be tuned to the desired

  10. Core Hunter 3: flexible core subset selection.

    Science.gov (United States)

    De Beukelaer, Herman; Davenport, Guy F; Fack, Veerle

    2018-05-31

    Core collections provide genebank curators and plant breeders a way to reduce size of their collections and populations, while minimizing impact on genetic diversity and allele frequency. Many methods have been proposed to generate core collections, often using distance metrics to quantify the similarity of two accessions, based on genetic marker data or phenotypic traits. Core Hunter is a multi-purpose core subset selection tool that uses local search algorithms to generate subsets relying on one or more metrics, including several distance metrics and allelic richness. In version 3 of Core Hunter (CH3) we have incorporated two new, improved methods for summarizing distances to quantify diversity or representativeness of the core collection. A comparison of CH3 and Core Hunter 2 (CH2) showed that these new metrics can be effectively optimized with less complex algorithms, as compared to those used in CH2. CH3 is more effective at maximizing the improved diversity metric than CH2, still ensures a high average and minimum distance, and is faster for large datasets. Using CH3, a simple stochastic hill-climber is able to find highly diverse core collections, and the more advanced parallel tempering algorithm further increases the quality of the core and further reduces variability across independent samples. We also evaluate the ability of CH3 to simultaneously maximize diversity, and either representativeness or allelic richness, and compare the results with those of the GDOpt and SimEli methods. CH3 can sample equally representative cores as GDOpt, which was specifically designed for this purpose, and is able to construct cores that are simultaneously more diverse, and either are more representative or have higher allelic richness, than those obtained by SimEli. In version 3, Core Hunter has been updated to include two new core subset selection metrics that construct cores for representativeness or diversity, with improved performance. It combines and outperforms the

  11. The Influence of Micro-Oxygen Addition on Desulfurization Performance and Microbial Communities during Waste-Activated Sludge Digestion in a Rusty Scrap Iron-Loaded Anaerobic Digester

    Directory of Open Access Journals (Sweden)

    Renjun Ruan

    2017-02-01

    Full Text Available In this study, micro-oxygen was integrated into a rusty scrap iron (RSI-loaded anaerobic digester. Under an optimal RSI dosage of 20 g/L, increasing O2 levels were added stepwise in seven stages in a semi-continuous experiment. Results showed the average methane yield was 306 mL/g COD (chemical oxygen demand, and the hydrogen sulphide (H2S concentration was 1933 ppmv with RSI addition. O2 addition induced the microbial oxidation of sulphide by stimulating sulfur-oxidizing bacteria and chemical corrosion of iron, which promoted the generation of FeS and Fe2S3. In the 6th phase of the semi-continuous test, deep desulfurization was achieved without negatively impacting system performance. Average methane yield was 301.1 mL/g COD, and H2S concentration was 75 ppmv. Sulfur mass balance was described, with 84.0%, 11.90% and 0.21% of sulfur present in solid, liquid and gaseous phases, respectively. The Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE analysis revealed that RSI addition could enrich the diversity of hydrogenotrophic methanogens and iron-reducing bacteria to benefit methanogenesis and organic mineralization, and impoverish the methanotroph (Methylocella silvestris to reduce the consumption of methane. Micro-oxygen supplementation could enhance the diversity of iron-oxidizing bacteria arising from the improvement of Fe(II release rate and enrich the sulphur-oxidising bacteria to achieved desulfurization. These results demonstrated that RSI addition in combination with micro-oxygenation represents a promising method for simultaneously controlling biogas H2S concentration and improving digestion performance.

  12. The Subset Sum game.

    Science.gov (United States)

    Darmann, Andreas; Nicosia, Gaia; Pferschy, Ulrich; Schauer, Joachim

    2014-03-16

    In this work we address a game theoretic variant of the Subset Sum problem, in which two decision makers (agents/players) compete for the usage of a common resource represented by a knapsack capacity. Each agent owns a set of integer weighted items and wants to maximize the total weight of its own items included in the knapsack. The solution is built as follows: Each agent, in turn, selects one of its items (not previously selected) and includes it in the knapsack if there is enough capacity. The process ends when the remaining capacity is too small for including any item left. We look at the problem from a single agent point of view and show that finding an optimal sequence of items to select is an [Formula: see text]-hard problem. Therefore we propose two natural heuristic strategies and analyze their worst-case performance when (1) the opponent is able to play optimally and (2) the opponent adopts a greedy strategy. From a centralized perspective we observe that some known results on the approximation of the classical Subset Sum can be effectively adapted to the multi-agent version of the problem.

  13. An Empirical Study of Wrappers for Feature Subset Selection based on a Parallel Genetic Algorithm: The Multi-Wrapper Model

    KAUST Repository

    Soufan, Othman

    2012-09-01

    Feature selection is the first task of any learning approach that is applied in major fields of biomedical, bioinformatics, robotics, natural language processing and social networking. In feature subset selection problem, a search methodology with a proper criterion seeks to find the best subset of features describing data (relevance) and achieving better performance (optimality). Wrapper approaches are feature selection methods which are wrapped around a classification algorithm and use a performance measure to select the best subset of features. We analyze the proper design of the objective function for the wrapper approach and highlight an objective based on several classification algorithms. We compare the wrapper approaches to different feature selection methods based on distance and information based criteria. Significant improvement in performance, computational time, and selection of minimally sized feature subsets is achieved by combining different objectives for the wrapper model. In addition, considering various classification methods in the feature selection process could lead to a global solution of desirable characteristics.

  14. CD14CD16 Monocyte Subset Levels in Heart Failure Patients

    Directory of Open Access Journals (Sweden)

    Chiara Barisione

    2010-01-01

    Full Text Available Our aim was to define the distribution of monocyte subsets in a cohort of congestive heart failure (CHF patients, to verify whether increased severity of CHF is linked to the expansion of specific monocyte subsets, and finally to investigate the relationship between monocyte subset relative frequencies, laboratory parameters of inflammation, and monocyte ACE expression.

  15. Yeast alter micro-oxygenation of wine: oxygen consumption and aldehyde production.

    Science.gov (United States)

    Han, Guomin; Webb, Michael R; Richter, Chandra; Parsons, Jessica; Waterhouse, Andrew L

    2017-08-01

    Micro-oxygenation (MOx) is a common winemaking treatment used to improve red wine color development and diminish vegetal aroma, amongst other effects. It is commonly applied to wine immediately after yeast fermentation (phase 1) or later, during aging (phase 2). Although most winemakers avoid MOx during malolactic (ML) fermentation, it is often not possible to avoid because ML bacteria are often present during phase 1 MOx treatment. We investigated the effect of common yeast and bacteria on the outcome of micro-oxygenation. Compared to sterile filtered wine, Saccharomyces cerevisiae inoculation significantly increased oxygen consumption, keeping dissolved oxygen in wine below 30 µg L -1 during micro-oxygenation, whereas Oenococcus oeni inoculation was not associated with a significant impact on the concentration of dissolved oxygen. The unfiltered baseline wine also had both present, although with much higher populations of bacteria and consumed oxygen. The yeast-treated wine yielded much higher levels of acetaldehyde, rising from 4.3 to 29 mg L -1 during micro-oxygenation, whereas no significant difference was found between the bacteria-treated wine and the filtered control. The unfiltered wine exhibited rapid oxygen consumption but no additional acetaldehyde, as well as reduced pyruvate. Analysis of the acetaldehyde-glycerol acetal levels showed a good correlation with acetaldehyde concentrations. The production of acetaldehyde is a key outcome of MOx and it is dramatically increased in the presence of yeast, although it is possibly counteracted by the metabolism of O. oeni bacteria. Additional controlled experiments are necessary to clarify the interaction of yeast and bacteria during MOx treatments. Analysis of the glycerol acetals may be useful as a proxy for acetaldehyde levels. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  16. On the size of the subset partial order

    DEFF Research Database (Denmark)

    Elmasry, Amr Ahmed Abd Elmoneim

    2012-01-01

    Given a family of k sets with cardinalities S 1,S 2,⋯, S k and N=Σ k i=1S i, we show that the size of the partial order graph induced by the subset relation (called the subset graph) is O(Σ si≤B 2si+N/lgN·Σ si>Blg(s i/B)), 2 where B=lg(N/lg 2N). This implies a simpler proof to the O(N 2/lg 2N...

  17. Effects of low dose radiation on regulatory function between lymphocyte subsets

    International Nuclear Information System (INIS)

    Tian Hailin; Su Liaoyuan; Du Zeji; Zou Huawei; Wang Aiqing

    1997-01-01

    Four kinds of McAbs (anti CD 4 , CD 8 , CD 19 and CD 57 ) were used to separate CD 4 , CD 8 , CD 19 (B) and CD 57 (NK) lymphocyte subsets from human peripheral blood by 'Panning-direct' method. First the natural killing activity of each subsets and the regulatory functions between CD 57 and other subsets were studied. Then the effects of low dose radiation on the function of CD 57 cells and the regulatory functions between CD 57 and other subsets were studied. The results showed that the NK activity was found in all of the four subsets, with CD 57 cell having the strongest activity. When CD 4 and CD 57 cells were co-cultured, the total NK activity was higher than that of the sum of these two single subsets, i.e. there was synergistic effect between CD 4 and CD 57 cells. When CD 8 or CD 19 cells were co-cultured separately with CD 57 cells, no synergistic effect was found. Irradiation by gamma rays at doses of 50 cGy and 80 cGy was able to stimulate the function of CD 57 cells. After Cd 4 or CD 57 cells were irradiated, the total NK activity of their co-culture increased significantly. This phenomenon was not found in other subsets. This suggested that low dose radiation can enhance the synergistic action between CD 4 and CD 57 cells. So at least four subsets (CD 4 , CD 8 , CD 19 , CD 57 ) contribute to the total NK activity of peripheral blood mononuclear cells. (15 refs., 4 tabs.)

  18. Effect of hydrophobic additive on oxygen transport in catalyst layer of proton exchange membrane fuel cells

    Science.gov (United States)

    Wang, Shunzhong; Li, Xiaohui; Wan, Zhaohui; Chen, Yanan; Tan, Jinting; Pan, Mu

    2018-03-01

    Oxygen transport resistance (OTR) is a critical factor influencing the performance of proton exchange membrane fuel cells (PEMFCs). In this paper, an effective method to reduce the OTR of catalyst layers (CLs) by introducing a hydrophobic additive into traditional CLs is proposed. A low-molecular-weight polytetrafluoroethylene (PTFE) is selected for its feasibility to prepare an emulsion, which is mixed with a traditional catalyst ink to successfully fabricate the CL with PTFE of 10 wt%. The PTFE film exists in the mesopores between the carbon particles. The limiting current of the hydrophobic CL was almost 4000 mA/cm2, which is 500 mA/cm2 higher than that of the traditional CL. PTFE reduces the OTR of the CL in the dry region by as much as 24 s/m compared to the traditional CL and expands the dry region from 2000 mA/cm2 in the traditional CL to 2500 mA/cm2. Furthermore, the CL with the hydrophobic agent can improve the oxygen transport in the wet region (>2000 mA/cm2) more effectively than that in the dry region. All these results indicate that the CL with the hydrophobic agent shows a superior performance in terms of optimizing water management and effectively reduces the OTR in PEMFCs.

  19. Susceptibility and response of human blood monocyte subsets to primary dengue virus infection.

    Directory of Open Access Journals (Sweden)

    Kok Loon Wong

    Full Text Available Human blood monocytes play a central role in dengue infections and form the majority of virus infected cells in the blood. Human blood monocytes are heterogeneous and divided into CD16(- and CD16(+ subsets. Monocyte subsets play distinct roles during disease, but it is not currently known if monocyte subsets differentially contribute to dengue protection and pathogenesis. Here, we compared the susceptibility and response of the human CD16(- and CD16(+ blood monocyte subsets to primary dengue virus in vitro. We found that both monocyte subsets were equally susceptible to dengue virus (DENV2 NGC, and capable of supporting the initial production of new infective virus particles. Both monocyte subsets produced anti-viral factors, including IFN-α, CXCL10 and TRAIL. However, CD16(+ monocytes were the major producers of inflammatory cytokines and chemokines in response to dengue virus, including IL-1β, TNF-α, IL-6, CCL2, 3 and 4. The susceptibility of both monocyte subsets to infection was increased after IL-4 treatment, but this increase was more profound for the CD16(+ monocyte subset, particularly at early time points after virus exposure. These findings reveal the differential role that monocyte subsets might play during dengue disease.

  20. Flow Cytometry Study of Lymphocyte Subsets in Malnourished and Well-Nourished Children with Bacterial Infections

    Science.gov (United States)

    Nájera, Oralia; González, Cristina; Toledo, Guadalupe; López, Laura; Ortiz, Rocío

    2004-01-01

    Protein-energy malnutrition is the primary cause of immune deficiency in children across the world. It has been related to changes in peripheral T-lymphocyte subsets. The aim of the present study was to evaluate the effects of infection and malnutrition on the proportion of peripheral-lymphocyte subsets in well-nourished non-bacterium-infected (WN), well-nourished bacterium-infected (WNI), and malnourished bacterium-infected (MNI) children by flow cytometry. A prospectively monitored cohort of 15 MNI, 12 WNI, and 17 WN children was studied. All the children were 3 years old or younger and had only bacterial infections. Results showed a significant decrease in the proportion of T CD3+ (P < 0.05 for relative and P < 0.03 for absolute values), CD4+ (P < 0.01 for relative and absolute values), and CD8+ (P < 0.05 for relative values) lymphocyte subsets in WNI children compared to the results seen with WN children. Additionally, B lymphocytes in MNI children showed significant lower values (CD20+ P < 0.02 for relative and P < 0.05 for absolute values) in relation to the results seen with WNI children. These results suggest that the decreased proportions of T-lymphocyte subsets observed in WNI children were associated with infection diseases and that the incapacity to increase the proportion of B lymphocyte was associated with malnutrition. This low proportion of B lymphocytes may be associated with the mechanisms involved in the immunodeficiency of malnourished children. PMID:15138185

  1. Listeria arpJ gene modifies T helper type 2 subset differentiation.

    Science.gov (United States)

    Kanoh, Makoto; Maruyama, Saho; Shen, Hua; Matsumoto, Akira; Shinomiya, Hiroto; Przybilla, Karin; Gouin, Edith; Cossart, Pascale; Goebel, Werner; Asano, Yoshihiro

    2015-07-15

    Although the T-cell subset differentiation pathway has been characterized extensively from the view of host gene regulation, the effects of genes of the pathogen on T-cell subset differentiation during infection have yet to be elucidated. Especially, the bacterial genes that are responsible for this shift have not yet been determined. Utilizing a single-gene-mutation Listeria panel, we investigated genes involved in the host-pathogen interaction that are required for the initiation of T-cell subset differentiation in the early phase of pathogen infection. We demonstrate that the induction of T helper types 1 and 2 (Th1 and Th2) subsets are separate phenomena and are mediated by distinct Listeria genes. We identified several candidate Listeria genes that appear to be involved in the host-Listeria interaction. Among them, arpJ is the strongest candidate gene for inhibiting Th2 subset induction. Furthermore, the analysis utilizing arpJ-deficient Listeria monocytogenes (Lm) revealed that the tumor necrosis factor (TNF) superfamily (Tnfsf) 9-TNF receptor superfamily (Tnfrsf) 9 interaction inhibits the Th2 response during Lm infection. arpJ is the candidate gene for inhibiting Th2 T-cell subset induction. The arpJ gene product influences the expression of Tnfsf/Tnfrsf on antigen-presenting cells and inhibits the Th2 T-cell subset differentiation during Listeria infection. © The Author 2015. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  2. Peripheral blood monocyte subsets predict antiviral response in chronic hepatitis C.

    Science.gov (United States)

    Rodríguez-Muñoz, Y; Martín-Vílchez, S; López-Rodríguez, R; Hernández-Bartolomé, A; Trapero-Marugán, M; Borque, M J; Moreno-Otero, R; Sanz-Cameno, P

    2011-10-01

    Hepatitis C virus infection evolves into chronic progressive liver disease in a significant percentage of patients. Monocytes constitute a diverse group of myeloid cells that mediate innate and adaptive immune response. In addition to proinflammatory CD16+ monocytes, a Tie-2+ subgroup - Tie-2 expressing monocytes (TEMs) - that has robust proangiogenic potential has been recently defined. To study the heterogeneity of peripheral blood monocytes in chronic hepatitis C (CHC) patients and to examine their proposed pathophysiological roles on disease progression and response to antiviral therapy. We studied CD16+ and Tie-2+ peripheral monocyte subpopulations in 21 healthy subjects and 39 CHC patients in various stages of disease and responses to antiviral treatment using flow cytometry. Expression profiles of proangiogenic and tissue remodelling factors in monocyte supernatants were measured using ELISA and protein arrays. Intrahepatic expression of CD14, CD31 and Tie-2 was analysed using immunofluorescence. Increases of certain peripheral monocyte subsets were observed in the blood of CHC patients, wherein those cells with proinflammatory (CD16+) or proangiogenic (TEMs) potential expanded (P TEMs were significantly increased in nonresponders, particularly those with lower CD16 expression. In addition, many angiogenic factors were differentially expressed by peripheral monocytes from control or CHC patients, such as angiopoietin-1 and angiogenin (P TEMs were distinguished within portal infiltrates of CHC patients. These findings suggest for the first time the relevance of peripheral monocytes phenotypes for the achievement of response to treatment. Hence, the study of monocyte subset regulation might effect improved CHC prognoses and adjuvant therapies. © 2011 Blackwell Publishing Ltd.

  3. Update on the use of dissolved oxygen addition to monitor the effectiveness of noble metal applications in external manifolds

    International Nuclear Information System (INIS)

    Varela, J.A.; Huie, H.H.; Seeman, R.A.; Bourne, C.M.; Odell, A.D.

    2014-01-01

    Electrochemical corrosion potential (ECP) measurements in a Mitigation Monitoring System (MMS) ECP manifold have historically been a primary indicator of the effectiveness of an On-Line NobleChem™ (OLNC) application, with the MMS ECP intended to measure the catalytic effect of noble metal deposited on the ECP manifold surface. In some plants ECP measurements made on untreated surfaces prior to an OLNC application were significantly lower than what would be expected for stainless steel under reactor bulk chemistry conditions. This is due to the consumption and depletion of bulk liquid dissolved oxygen (DO) in the lines supplying reactor water to these external ECP measurement locations. This phenomenon degrades the ability to use these external manifolds to confirm noble metal deposition. Previous papers have described how the injection of an oxygen-rich stream to the MMS supply stream (DO Addition) can be used to re-establish the capability of external ECP measurements to monitor the catalytic behavior of platinum deposited during an OLNC injection. This paper will provide an update of how this method is being successfully used in operating BWRs to monitor OLNC injections. The paper will outline the overall approach used to characterize the catalytic behavior of external ECP manifolds before and after the noble metal application and present plant data collected during DO Additions performed under various conditions. (author)

  4. The efficiency of subset selection of an almost best treatment

    NARCIS (Netherlands)

    Laan, van der P.

    1991-01-01

    A generalized goal using subset selection is discussed for the location parameter case. This goal is to select a non-empty subset from a set of k (k \\geq 2) treatments that contains at least one \\epsilon-best treatment with confidence level P*. For a set of treatments an \\epsilon-best treatment is

  5. Roquin Paralogs Differentially Regulate Functional NKT Cell Subsets.

    Science.gov (United States)

    Drees, Christoph; Vahl, J Christoph; Bortoluzzi, Sabrina; Heger, Klaus D; Fischer, Julius C; Wunderlich, F Thomas; Peschel, Christian; Schmidt-Supprian, Marc

    2017-04-01

    NKT cells represent a small subset of glycolipid-recognizing T cells that are heavily implicated in human allergic, autoimmune, and malignant diseases. In the thymus, precursor cells recognize self-glycolipids by virtue of their semi-invariant TCR, which triggers NKT cell lineage commitment and maturation. During their development, NKT cells are polarized into the NKT1, NKT2, and NKT17 subsets, defined through their cytokine-secretion patterns and the expression of key transcription factors. However, we have largely ignored how the differentiation into the NKT cell subsets is regulated. In this article, we describe the mRNA-binding Roquin-1 and -2 proteins as central regulators of murine NKT cell fate decisions. In the thymus, T cell-specific ablation of the Roquin paralogs leads to a dramatic expansion of NKT17 cells, whereas peripheral mature NKT cells are essentially absent. Roquin-1/2-deficient NKT17 cells show exaggerated lineage-specific expression of nearly all NKT17-defining proteins tested. We show through mixed bone marrow chimera experiments that NKT17 polarization is mediated through cell-intrinsic mechanisms early during NKT cell development. In contrast, the loss of peripheral NKT cells is due to cell-extrinsic factors. Surprisingly, Roquin paralog-deficient NKT cells are, in striking contrast to conventional T cells, compromised in their ability to secrete cytokines. Altogether, we show that Roquin paralogs regulate the development and function of NKT cell subsets in the thymus and periphery. Copyright © 2017 by The American Association of Immunologists, Inc.

  6. Investigating evolutionary conservation of dendritic cell subset identity and functions

    Directory of Open Access Journals (Sweden)

    Thien-Phong eVu Manh

    2015-06-01

    Full Text Available Dendritic cells (DC were initially defined as mononuclear phagocytes with a dendritic morphology and an exquisite efficiency for naïve T cell activation. DC encompass several subsets initially identified by their expression of specific cell surface molecules and later shown to excel in distinct functions and to develop under the instruction of different transcription factors or cytokines. Very few cell surface molecules are expressed in a specific manner on any immune cell type. Hence, to identify cell types, the sole use of a small number of cell surface markers in classical flow cytometry can be deceiving. Moreover, the markers currently used to define mononuclear phagocyte subsets vary depending on the tissue and animal species studied and even between laboratories. This has led to confusion in the definition of DC subset identity and in their attribution of specific functions. There is a strong need to identify a rigorous and consensus way to define mononuclear phagocyte subsets, with precise guidelines potentially applicable throughout tissues and species. We will discuss the advantages, drawbacks and complementarities of different methodologies: cell surface phenotyping, ontogeny, functional characterization and molecular profiling. We will advocate that gene expression profiling is a very rigorous, largely unbiased and accessible method to define the identity of mononuclear phagocyte subsets, which strengthens and refines surface phenotyping. It is uniquely powerful to yield new, experimentally testable, hypotheses on the ontogeny or functions of mononuclear phagocyte subsets, their molecular regulation and their evolutionary conservation. We propose defining cell populations based on a combination of cell surface phenotyping, expression analysis of hallmark genes and robust functional assays, in order to reach a consensus and integrate faster the huge but scattered knowledge accumulated by different laboratories on different cell types

  7. Non-suppressive regulatory T cell subset expansion in pulmonary arterial hypertension.

    Science.gov (United States)

    Sada, Yoshiharu; Dohi, Yoshihiro; Uga, Sayuri; Higashi, Akifumi; Kinoshita, Hiroki; Kihara, Yasuki

    2016-08-01

    Regulatory T cells (Tregs) have been reported to play a pivotal role in the vascular remodeling of pulmonary arterial hypertension (PAH). Recent studies have revealed that Tregs are heterogeneous and can be characterized by three phenotypically and functionally different subsets. In this study, we investigated the roles of Treg subsets in the pathogenesis of PAH in eight patients with PAH and 14 healthy controls. Tregs and their subsets in peripheral blood samples were analyzed by flow cytometry. Treg subsets were defined as CD4(+)CD45RA(+)FoxP3(low) resting Tregs (rTregs), CD4(+)CD45RA(-)FoxP3(high) activated Tregs (aTregs), and CD4(+)CD45RA(-)FoxP3(low) non-suppressive Tregs (non-Tregs). The proportion of Tregs among CD4(+) T cells was significantly higher in PAH patients than in controls (6.54 ± 1.10 vs. 3.81 ± 0.28 %, p < 0.05). Of the three subsets, the proportion of non-Tregs was significantly elevated in PAH patients compared with controls (4.06 ± 0.40 vs. 2.79 ± 0.14 %, p < 0.01), whereas those of rTregs and aTregs were not different between the two groups. Moreover, the expression levels of cytotoxic T lymphocyte antigen 4, a functional cell surface molecule, in aTregs (p < 0.05) and non-Tregs (p < 0.05) were significantly higher in PAH patients compared with controls. These results suggested the non-Treg subset was expanded and functionally activated in peripheral lymphocytes obtained from IPAH patients. We hypothesize that immunoreactions involving the specific activation of the non-Treg subset might play a role in the vascular remodeling of PAH.

  8. Probabilistic quantum cloning of a subset of linearly dependent states

    Science.gov (United States)

    Rui, Pinshu; Zhang, Wen; Liao, Yanlin; Zhang, Ziyun

    2018-02-01

    It is well known that a quantum state, secretly chosen from a certain set, can be probabilistically cloned with positive cloning efficiencies if and only if all the states in the set are linearly independent. In this paper, we focus on probabilistic quantum cloning of a subset of linearly dependent states. We show that a linearly-independent subset of linearly-dependent quantum states {| Ψ 1⟩,| Ψ 2⟩,…,| Ψ n ⟩} can be probabilistically cloned if and only if any state in the subset cannot be expressed as a linear superposition of the other states in the set {| Ψ 1⟩,| Ψ 2⟩,…,| Ψ n ⟩}. The optimal cloning efficiencies are also investigated.

  9. Statistical image reconstruction for transmission tomography using relaxed ordered subset algorithms

    International Nuclear Information System (INIS)

    Kole, J S

    2005-01-01

    Statistical reconstruction methods offer possibilities for improving image quality as compared to analytical methods, but current reconstruction times prohibit routine clinical applications in x-ray computed tomography (CT). To reduce reconstruction times, we have applied (under) relaxation to ordered subset algorithms. This enables us to use subsets consisting of only single projection angle, effectively increasing the number of image updates within an entire iteration. A second advantage of applying relaxation is that it can help improve convergence by removing the limit cycle behaviour of ordered subset algorithms, which normally do not converge to an optimal solution but rather a suboptimal limit cycle consisting of as many points as there are subsets. Relaxation suppresses the limit cycle behaviour by decreasing the stepsize for approaching the solution. A simulation study for a 2D mathematical phantom and three different ordered subset algorithms shows that all three algorithms benefit from relaxation: equal noise-to-resolution trade-off can be achieved using fewer iterations than the conventional algorithms, while a lower minimal normalized mean square error (NMSE) clearly indicates a better convergence. Two different schemes for setting the relaxation parameter are studied, and both schemes yield approximately the same minimal NMSE

  10. A Quantum Approach to Subset-Sum and Similar Problems

    OpenAIRE

    Daskin, Ammar

    2017-01-01

    In this paper, we study the subset-sum problem by using a quantum heuristic approach similar to the verification circuit of quantum Arthur-Merlin games. Under described certain assumptions, we show that the exact solution of the subset sum problem my be obtained in polynomial time and the exponential speed-up over the classical algorithms may be possible. We give a numerical example and discuss the complexity of the approach and its further application to the knapsack problem.

  11. Simultaneous gettering of oxygen and chlorine and homogenization of the β phase by rare earth hydride additions to a powder metallurgy Ti–2.25Mo–1.5Fe alloy

    International Nuclear Information System (INIS)

    Yan, M.; Liu, Y.; Liu, Y.B.; Kong, C.; Schaffer, G.B.; Qian, M.

    2012-01-01

    A detailed transmission electron microscopy analysis has revealed that small additions of yttrium hydride to a powder metallurgy Ti–2.25Mo–1.5Fe alloy resulted in the formation of both chlorine-free yttrium oxides and essentially oxygen-free yttrium chlorides. The oxides and chlorides showed distinctly different morphologies and spatial distribution. Yttrium acted as a potent getter for both oxygen and chlorine. Additionally, the β-Ti phase was free of nanoscaled α-Ti in the presence of yttrium. These microstructural changes contribute to the substantially increased ductility (∼90%).

  12. Dependence of nitrite oxidation on nitrite and oxygen in low-oxygen seawater

    Science.gov (United States)

    Sun, Xin; Ji, Qixing; Jayakumar, Amal; Ward, Bess B.

    2017-08-01

    Nitrite oxidation is an essential step in transformations of fixed nitrogen. The physiology of nitrite oxidizing bacteria (NOB) implies that the rates of nitrite oxidation should be controlled by concentration of their substrate, nitrite, and the terminal electron acceptor, oxygen. The sensitivities of nitrite oxidation to oxygen and nitrite concentrations were investigated using 15N tracer incubations in the Eastern Tropical North Pacific. Nitrite stimulated nitrite oxidation under low in situ nitrite conditions, following Michaelis-Menten kinetics, indicating that nitrite was the limiting substrate. The nitrite half-saturation constant (Ks = 0.254 ± 0.161 μM) was 1-3 orders of magnitude lower than in cultivated NOB, indicating higher affinity of marine NOB for nitrite. The highest rates of nitrite oxidation were measured in the oxygen depleted zone (ODZ), and were partially inhibited by additions of oxygen. This oxygen sensitivity suggests that ODZ specialist NOB, adapted to low-oxygen conditions, are responsible for apparently anaerobic nitrite oxidation.

  13. Indirect Positive Evidence in the Acquisition of a Subset Grammar

    Science.gov (United States)

    Schwartz, Misha; Goad, Heather

    2017-01-01

    This article proposes that second language learners can use indirect positive evidence (IPE) to acquire a phonological grammar that is a subset of their L1 grammar. IPE is evidence from errors in the learner's L1 made by native speakers of the learner's L2. It has been assumed that subset grammars may be acquired using direct or indirect negative…

  14. Non-self-sustained electric discharge in oxygen gas mixtures: singlet delta oxygen production

    CERN Document Server

    Ionin, A A; Kotkov, A A; Kochetov, I V; Napartovich, A P; Seleznev, L V; Sinitsyn, D V; Hager, G D

    2003-01-01

    The possibility of obtaining a high specific input energy in an electron-beam sustained discharge ignited in oxygen gas mixtures O sub 2 : Ar : CO (or H sub 2) at the total gas pressures of 10-100 Torr was experimentally demonstrated. The specific input energy per molecular component exceeded approx 6 kJ l sup - sup 1 atm sup - sup 1 (150 kJ mol sup - sup 1) as a small amount of carbon monoxide was added into a gas mixture of oxygen and argon. It was theoretically demonstrated that one might expect to obtain a singlet delta oxygen yield of 25% exceeding its threshold value needed for an oxygen-iodine laser operation at room temperature, when maintaining a non-self-sustained discharge in oxygen gas mixtures with molecular additives CO, H sub 2 or D sub 2. The efficiency of singlet delta oxygen production can be as high as 40%.

  15. Circulating regulatory B cell subsets in patients with neuromyelitis optica spectrum disorders.

    Science.gov (United States)

    Han, Jinming; Sun, Li; Wang, Zhongkun; Fan, Xueli; Wang, Lifang; Song, Yang-Yang; Zhu, Jie; Jin, Tao

    2017-07-01

    This study analyzed the populations of three different subsets of regulatory B cells (Bregs) in the peripheral blood mononuclear cells (PBMCs) of patients with neuromyelitis optica spectrum disorders (NMOSDs) and explored the relationship between the changes in these subsets of Bregs and the severity of NMOSD. A total of 22 patients with relapsed NMOSDs before treatment were recruited in our study, along with 20 age and gender-matched healthy controls, from May 2015 to March 2016. The percentages and numbers for three different subsets of Bregs including the CD19 + CD24 hi CD38 hi , CD19 + CD24 hi CD27 + , and CD19 + CD5 + CD1d hi populations were evaluated in parallel by flow cytometry. Afterwards, correlations between the change of three different subsets of Bregs and disease severity were analyzed. We found significantly lower percentages of CD19 + CD24 hi CD38 hi and CD19 + CD5 + CD1d hi Bregs in NMOSDs patients than in healthy individuals. In contrast, the CD19 + CD24 hi CD27 + Bregs population was significantly higher in NMOSDs patients than in healthy individuals. However, the three different Bregs subsets showed no significant correlation with expanded disability status scale (EDSS) or annualized relapse rate (ARR). Our findings suggest that the subsets of Bregs may play complex roles in the pathogenesis of NMOSDs and are not correlated with clinical disease severity. Further insights into the potential role of subsets of Bregs could increase our basic knowledge of NMOSDs pathogenesis.

  16. In vivo integrated photoacoustic and confocal microscopy of hemoglobin oxygen saturation and oxygen partial pressure.

    Science.gov (United States)

    Wang, Yu; Hu, Song; Maslov, Konstantin; Zhang, Yu; Xia, Younan; Wang, Lihong V

    2011-04-01

    We developed dual-modality microscope integrating photoacoustic microscopy (PAM) and fluorescence confocal microscopy (FCM) to noninvasively image hemoglobin oxygen saturation (sO₂) and oxygen partial pressure (pO₂) in vivo in single blood vessels with high spatial resolution. While PAM measures sO₂ by imaging hemoglobin optical absorption at two wavelengths, FCM quantifies pO₂ using phosphorescence quenching. The variations of sO₂ and pO₂ values in multiple orders of vessel branches under hyperoxic (100% oxygen) and normoxic (21% oxygen) conditions correlate well with the oxygen-hemoglobin dissociation curve. In addition, the total concentration of hemoglobin is imaged by PAM at an isosbestic wavelength.

  17. Diagnosing Warm Frontal Cloud Formation in a GCM: A Novel Approach Using Conditional Subsetting

    Science.gov (United States)

    Booth, James F.; Naud, Catherine M.; DelGenio, Anthony D.

    2013-01-01

    This study analyzes characteristics of clouds and vertical motion across extratropical cyclone warm fronts in the NASA Goddard Institute for Space Studies general circulation model. The validity of the modeled clouds is assessed using a combination of satellite observations from CloudSat, Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO), Advanced Microwave Scanning Radiometer for Earth Observing System (AMSR-E), and the NASA Modern-Era Retrospective Analysis for Research and Applications (MERRA) reanalysis. The analysis focuses on developing cyclones, to test the model's ability to generate their initial structure. To begin, the extratropical cyclones and their warm fronts are objectively identified and cyclone-local fields are mapped into a vertical transect centered on the surface warm front. To further isolate specific physics, the cyclones are separated using conditional subsetting based on additional cyclone-local variables, and the differences between the subset means are analyzed. Conditional subsets are created based on 1) the transect clouds and 2) vertical motion; 3) the strength of the temperature gradient along the warm front, as well as the storm-local 4) wind speed and 5) precipitable water (PW). The analysis shows that the model does not generate enough frontal cloud, especially at low altitude. The subsetting results reveal that, compared to the observations, the model exhibits a decoupling between cloud formation at high and low altitudes across warm fronts and a weak sensitivity to moisture. These issues are caused in part by the parameterized convection and assumptions in the stratiform cloud scheme that are valid in the subtropics. On the other hand, the model generates proper covariability of low-altitude vertical motion and cloud at the warm front and a joint dependence of cloudiness on wind and PW.

  18. Ambient oxygen promotes tumorigenesis.

    Directory of Open Access Journals (Sweden)

    Ho Joong Sung

    2011-05-01

    Full Text Available Oxygen serves as an essential factor for oxidative stress, and it has been shown to be a mutagen in bacteria. While it is well established that ambient oxygen can also cause genomic instability in cultured mammalian cells, its effect on de novo tumorigenesis at the organismal level is unclear. Herein, by decreasing ambient oxygen exposure, we report a ∼50% increase in the median tumor-free survival time of p53-/- mice. In the thymus, reducing oxygen exposure decreased the levels of oxidative DNA damage and RAG recombinase, both of which are known to promote lymphomagenesis in p53-/- mice. Oxygen is further shown to be associated with genomic instability in two additional cancer models involving the APC tumor suppressor gene and chemical carcinogenesis. Together, these observations represent the first report directly testing the effect of ambient oxygen on de novo tumorigenesis and provide important physiologic evidence demonstrating its critical role in increasing genomic instability in vivo.

  19. T-lymphocyte subsets in West African children: impact of age, sex, and season

    DEFF Research Database (Denmark)

    Lisse, I M; Aaby, P; Whittle, H

    1997-01-01

    method to determine T-lymphocyte subsets. RESULTS: We found differences by age, sex, and season, whereas there were no significant differences by birth order, twinning, or ethnic group. The CD4+ percentage declined from birth to age 2 years, at which time it started to increase to higher levels at age 4......OBJECTIVE: There has been no reference material for T-lymphocyte subsets for normal children in developing countries. We therefore used T-lymphocyte subset determinations among children in three different studies in Guinea-Bissau to construct age-related reference material and to examine possible...... determinants of T-lymphocyte subset levels. METHODS: A total of 803 healthy West African children younger than 6 years were included in the three community studies of T-lymphocyte subsets among twins and singletons, after measles infection and after measles immunization. We used the immunoalkaline phosphatase...

  20. Effects of oxygen addition in reactive cluster beam deposition of tungsten by magnetron sputtering with gas aggregation

    Energy Technology Data Exchange (ETDEWEB)

    Polášek, J., E-mail: xpolasekj@seznam.cz [Department of Surface and Plasma Science, Faculty of Mathematics and Physic, Charles University, V Holešovičkách 2, Prague 8, CZ-18000 (Czech Republic); Mašek, K. [Department of Surface and Plasma Science, Faculty of Mathematics and Physic, Charles University, V Holešovičkách 2, Prague 8, CZ-18000 (Czech Republic); Marek, A.; Vyskočil, J. [HVM Plasma Ltd., Na Hutmance 2, Prague 5, CZ-158 00 (Czech Republic)

    2015-09-30

    In this work, we investigated the possibilities of tungsten and tungsten oxide nanoclusters generation by means of non-reactive and reactive magnetron sputtering with gas aggregation. It was found that in pure argon atmosphere, cluster aggregation proceeded in two regimes depending on argon pressure in the aggregation chamber. At the lower pressure, cluster generation was dominated by two-body collisions yielding larger clusters (about 5.5 nm in diameter) at lower rate. At higher pressures, cluster generation was dominated by three-body collisions yielding smaller clusters (3–4 nm in diameter) at higher rate. The small amount of oxygen admixture in the aggregation chamber had considerable influence on cluster aggregation process. At certain critical pressure, the presence of oxygen led to the raise of deposition rate and cluster size. Resulting clusters were composed mostly of tungsten trioxide. The oxygen pressure higher than critical led to the target poisoning and the decrease in the sputtering rate. Critical oxygen pressure decreased with increasing argon pressure, suggesting that cluster aggregation process was influenced by atomic oxygen species (namely, O{sup −} ion) generated by oxygen–argon collisions in the magnetron plasma. - Highlights: • Formation of tungsten and tungsten oxide clusters was observed. • Two modes of cluster aggregation in pure argon atmosphere were found. • Dependence of cluster deposition speed and size on oxygen admixture was observed. • Changes of dependence on oxygen with changing argon pressure were described.

  1. Effects of oxygen addition in reactive cluster beam deposition of tungsten by magnetron sputtering with gas aggregation

    International Nuclear Information System (INIS)

    Polášek, J.; Mašek, K.; Marek, A.; Vyskočil, J.

    2015-01-01

    In this work, we investigated the possibilities of tungsten and tungsten oxide nanoclusters generation by means of non-reactive and reactive magnetron sputtering with gas aggregation. It was found that in pure argon atmosphere, cluster aggregation proceeded in two regimes depending on argon pressure in the aggregation chamber. At the lower pressure, cluster generation was dominated by two-body collisions yielding larger clusters (about 5.5 nm in diameter) at lower rate. At higher pressures, cluster generation was dominated by three-body collisions yielding smaller clusters (3–4 nm in diameter) at higher rate. The small amount of oxygen admixture in the aggregation chamber had considerable influence on cluster aggregation process. At certain critical pressure, the presence of oxygen led to the raise of deposition rate and cluster size. Resulting clusters were composed mostly of tungsten trioxide. The oxygen pressure higher than critical led to the target poisoning and the decrease in the sputtering rate. Critical oxygen pressure decreased with increasing argon pressure, suggesting that cluster aggregation process was influenced by atomic oxygen species (namely, O"− ion) generated by oxygen–argon collisions in the magnetron plasma. - Highlights: • Formation of tungsten and tungsten oxide clusters was observed. • Two modes of cluster aggregation in pure argon atmosphere were found. • Dependence of cluster deposition speed and size on oxygen admixture was observed. • Changes of dependence on oxygen with changing argon pressure were described.

  2. Oxygen and nitrogen plasma etching of three-dimensional hydroxyapatite/chitosan scaffolds fabricated by additive manufacturing

    Science.gov (United States)

    Myung, Sung-Woon; Kim, Byung-Hoon

    2016-01-01

    Three-dimensional (3D) chitosan and hydroxyapatite (HAp)/chitosan (CH) scaffolds were fabricated by additive manufacturing, then their surfaces were etched with oxygen (O2) and nitrogen (N2) plasma. O2 and N2 plasma etching was performed to increase surface properties such as hydrophilicity, roughness, and surface chemistry on the scaffolds. After etching, hydroxyapatite was exposed on the surface of 3D HAp/CH scaffolds. The surface morphology and chemical properties were characterized by contact angle measurement, scanning electron microscopy, X-ray diffraction, and attenuated total reflection Fourier infrared spectroscopy. The cell viability of 3D chitosan scaffolds was examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The differentiation of preosteoblast cells was evaluated by alkaline phosphatase assay. The cell viability was improved by O2 and N2 plasma etching of 3D chitosan scaffolds. The present fabrication process for 3D scaffolds might be applied to a potential tool for preparing biocompatible scaffolds.

  3. Normal Hematopoietic Progenitor Subsets Have Distinct Reactive Oxygen Species, BCL2 and Cell-Cycle Profiles That Are Decoupled from Maturation in Acute Myeloid Leukemia.

    Directory of Open Access Journals (Sweden)

    Naeem Khan

    Full Text Available In acute myeloid leukemia (AML quiescence and low oxidative state, linked to BCL2 mitochondrial regulation, endow leukemic stem cells (LSC with treatment-resistance. LSC in CD34+ and more mature CD34- AML have heterogeneous immunophenotypes overlapping with normal stem/progenitor cells (SPC but may be differentiated by functional markers. We therefore investigated the oxidative/reactive oxygen species (ROS profile, its relationship with cell-cycle/BCL2 for normal SPC, and whether altered in AML and myelodysplasia (MDS. In control BM (n = 24, ROS levels were highest in granulocyte-macrophage progenitors (GMP and CD34- myeloid precursors but megakaryocyte-erythroid progenitors had equivalent levels to CD34+CD38low immature-SPC although they were ki67high. BCL2 upregulation was specific to GMPs. This profile was also observed for CD34+SPC in MDS-without-excess-blasts (MDS-noEB, n = 12. Erythroid CD34- precursors were, however, abnormally ROS-high in MDS-noEB, potentially linking oxidative stress to cell loss. In pre-treatment AML (n = 93 and MDS-with-excess-blasts (MDS-RAEB (n = 14, immunophenotypic mature-SPC had similar ROS levels to co-existing immature-SPC. However ROS levels varied between AMLs; Flt3ITD+/NPM1wild-type CD34+SPC had higher ROS than NPM1mutated CD34+ or CD34- SPC. An aberrant ki67lowBCL2high immunophenotype was observed in CD34+AML (most prominent in Flt3ITD AMLs but also in CD34- AMLs and MDS-RAEB, suggesting a shared redox/pro-survival adaptation. Some patients had BCL2 overexpression in CD34+ ROS-high as well as ROS-low fractions which may be indicative of poor early response to standard chemotherapy. Thus normal SPC subsets have distinct ROS, cell-cycle, BCL2 profiles that in AML /MDS-RAEB are decoupled from maturation. The combined profile of these functional properties in AML subpopulations may be relevant to differential treatment resistance.

  4. Oxygen Isotopes in Chondritic Interplanetary Dust: Parent-Bodies and Nebular Oxygen Reservoirs

    International Nuclear Information System (INIS)

    Aleon, J; McKeegan, K D; Leshin, L

    2006-01-01

    Planetary objects have preserved various amounts of oxygen issued from isotopically different oxygen reservoirs reflecting their origin and physico-chemical history. An 16 O-rich component is preserved in refractory inclusions (CAIs) whereas meteorites matrices are enriched in an 16 O-poor component. The origin of these components is still unclear. The most recent models are based on isotope selective photodissociation of CO in a 16 O-rich nebula/presolr cloud resulting in a 16 O-poor gas in the outer part of the nebula. However because most meteorite components are thought to be formed in the inner 3AU of the solar nebula, the precise isotopic composition of outer solar system components is yet unknown. In that respect, the oxygen isotopic composition of cometary dust is a key to understand the origin of the solar system. The Stardust mission will bring back to the Earth dust samples from comet Wild2, a short period comet from the Jupiter family. A precise determination of the oxygen isotope composition of Wild2 dust grains is essential to decipher the oxygen reservoirs of the outer solar system. However, Stardust samples may be extremely fragmented upon impact in the collector. In addition, interplanetary dust particles (IDPs) collected in the stratosphere are likely to contain comet samples. Therefore, they started to investigate the oxygen isotopic composition of a suite of chondritic interplanetary dust particles that includes IDPs of potential cometary origin using a refined procedure to increase the lateral resolution for the analysis of Stardust grains or IDP subcomponents down to ∼ 3 (micro)m. High precision data for 4 IDPs were previously reported, here they have measured 6 additional IDPs

  5. A systems biology approach to the analysis of subset-specific responses to lipopolysaccharide in dendritic cells.

    Science.gov (United States)

    Hancock, David G; Shklovskaya, Elena; Guy, Thomas V; Falsafi, Reza; Fjell, Chris D; Ritchie, William; Hancock, Robert E W; Fazekas de St Groth, Barbara

    2014-01-01

    Dendritic cells (DCs) are critical for regulating CD4 and CD8 T cell immunity, controlling Th1, Th2, and Th17 commitment, generating inducible Tregs, and mediating tolerance. It is believed that distinct DC subsets have evolved to control these different immune outcomes. However, how DC subsets mount different responses to inflammatory and/or tolerogenic signals in order to accomplish their divergent functions remains unclear. Lipopolysaccharide (LPS) provides an excellent model for investigating responses in closely related splenic DC subsets, as all subsets express the LPS receptor TLR4 and respond to LPS in vitro. However, previous studies of the LPS-induced DC transcriptome have been performed only on mixed DC populations. Moreover, comparisons of the in vivo response of two closely related DC subsets to LPS stimulation have not been reported in the literature to date. We compared the transcriptomes of murine splenic CD8 and CD11b DC subsets after in vivo LPS stimulation, using RNA-Seq and systems biology approaches. We identified subset-specific gene signatures, which included multiple functional immune mediators unique to each subset. To explain the observed subset-specific differences, we used a network analysis approach. While both DC subsets used a conserved set of transcription factors and major signalling pathways, the subsets showed differential regulation of sets of genes that 'fine-tune' the network Hubs expressed in common. We propose a model in which signalling through common pathway components is 'fine-tuned' by transcriptional control of subset-specific modulators, thus allowing for distinct functional outcomes in closely related DC subsets. We extend this analysis to comparable datasets from the literature and confirm that our model can account for cell subset-specific responses to LPS stimulation in multiple subpopulations in mouse and man.

  6. Design of focused and restrained subsets from extremely large virtual libraries.

    Science.gov (United States)

    Jamois, Eric A; Lin, Chien T; Waldman, Marvin

    2003-11-01

    With the current and ever-growing offering of reagents along with the vast palette of organic reactions, virtual libraries accessible to combinatorial chemists can reach sizes of billions of compounds or more. Extracting practical size subsets for experimentation has remained an essential step in the design of combinatorial libraries. A typical approach to computational library design involves enumeration of structures and properties for the entire virtual library, which may be unpractical for such large libraries. This study describes a new approach termed as on the fly optimization (OTFO) where descriptors are computed as needed within the subset optimization cycle and without intermediate enumeration of structures. Results reported herein highlight the advantages of coupling an ultra-fast descriptor calculation engine to subset optimization capabilities. We also show that enumeration of properties for the entire virtual library may not only be unpractical but also wasteful. Successful design of focused and restrained subsets can be achieved while sampling only a small fraction of the virtual library. We also investigate the stability of the method and compare results obtained from simulated annealing (SA) and genetic algorithms (GA).

  7. Distributional and efficiency results for subset selection

    NARCIS (Netherlands)

    Laan, van der P.

    1996-01-01

    Assume k (??k \\geq 2) populations are given. The associated independent random variables have continuous distribution functions with an unknown location parameter. The statistical selec??tion goal is to select a non??empty subset which contains the best population,?? that is the pop??ulation with

  8. Design of a verifiable subset for HAL/S

    Science.gov (United States)

    Browne, J. C.; Good, D. I.; Tripathi, A. R.; Young, W. D.

    1979-01-01

    An attempt to evaluate the applicability of program verification techniques to the existing programming language, HAL/S is discussed. HAL/S is a general purpose high level language designed to accommodate the software needs of the NASA Space Shuttle project. A diversity of features for scientific computing, concurrent and real-time programming, and error handling are discussed. The criteria by which features were evaluated for inclusion into the verifiable subset are described. Individual features of HAL/S with respect to these criteria are examined and justification for the omission of various features from the subset is provided. Conclusions drawn from the research are presented along with recommendations made for the use of HAL/S with respect to the area of program verification.

  9. Mars oxygen production system design

    Science.gov (United States)

    Cotton, Charles E.; Pillow, Linda K.; Perkinson, Robert C.; Brownlie, R. P.; Chwalowski, P.; Carmona, M. F.; Coopersmith, J. P.; Goff, J. C.; Harvey, L. L.; Kovacs, L. A.

    1989-01-01

    The design and construction phase is summarized of the Mars oxygen demonstration project. The basic hardware required to produce oxygen from simulated Mars atmosphere was assembled and tested. Some design problems still remain with the sample collection and storage system. In addition, design and development of computer compatible data acquisition and control instrumentation is ongoing.

  10. Circulating TFH subset distribution is strongly affected in lupus patients with an active disease.

    Directory of Open Access Journals (Sweden)

    Carole Le Coz

    Full Text Available Follicular helper T cells (TFH represent a distinct subset of CD4(+ T cells specialized in providing help to B lymphocytes, which may play a central role in autoimmune diseases having a major B cell component such as systemic lupus erythematosus. Recently, TFH subsets that share common phenotypic and functional characteristics with TFH cells from germinal centers, have been described in the peripheral blood from healthy individuals. The aim of this study was to analyze the distribution of such populations in lupus patients. Circulating TFH cell subsets were defined by multicolor flow cytometry as TFH17 (CXCR3(-CCR6(+, TFH1 (CXCR3 (+ CCR6(- or TFH2 (CXCR3(-CCR6(- cells among CXCR5 (+ CD45RA(-CD4(+ T cells in the peripheral blood of 23 SLE patients and 23 sex and age-matched healthy controls. IL-21 receptor expression by B cells was analyzed by flow cytometry and the serum levels of IL-21 and Igs were determined by ELISA tests. We found that the TFH2 cell subset frequency is strongly and significantly increased in lupus patients with an active disease (SLEDAI score>8, while the TFH1 cell subset percentage is greatly decreased. The TFH2 and TFH1 cell subset frequency alteration is associated with the presence of high Ig levels and autoantibodies in patient's sera. Moreover, the TFH2 cell subset enhancement correlates with an increased frequency of double negative memory B cells (CD27(-IgD(-CD19(+ cells expressing the IL-21R. Finally, we found that IgE levels in lupus patients' sera correlate with disease activity and seem to be associated with high TFH2 cell subset frequency. In conclusion, our study describes for the first time the distribution of circulating TFH cell subsets in lupus patients. Interestingly, we found an increased frequency of TFH2 cells, which correlates with disease activity. Our results suggest that this subset might play a key role in lupus pathogenesis.

  11. Report on ISS Oxygen Production, Resupply, and Partial Pressure Management

    Science.gov (United States)

    Schaezler, Ryan; Ghariani, Ahmed; Leonard, Daniel; Lehman, Daniel

    2011-01-01

    The majority of oxygen used on International Space Station (ISS) is for metabolic support and denitrogenation procedures prior to Extra-Vehicular Activities. Oxygen is supplied by various visiting vehicles such as the Progress and Shuttle in addition to oxygen production capability on both the United States On-Orbit Segment (USOS) and Russian Segment (RS). To maintain a habitable atmosphere the oxygen partial pressure is controlled between upper and lower bounds. The full range of the allowable oxygen partial pressure along with the increased ISS cabin volume is utilized as a buffer allowing days to pass between oxygen production or direct addition of oxygen to the atmosphere from reserves. This paper summarizes amount of oxygen supplied and produced from all of the sources and describes past experience of managing oxygen partial pressure along with the range of management options available to the ISS.

  12. Gradually Increased Oxygen Administration Improved Oxygenation and Mitigated Oxidative Stress after Resuscitation from Severe Hemorrhagic Shock.

    Science.gov (United States)

    Luo, Xin; Yin, Yujing; You, Guoxing; Chen, Gan; Wang, Ying; Zhao, Jingxiang; Wang, Bo; Zhao, Lian; Zhou, Hong

    2015-11-01

    The optimal oxygen administration strategy during resuscitation from hemorrhagic shock (HS) is still controversial. Improving oxygenation and mitigating oxidative stress simultaneously seem to be contradictory goals. To maximize oxygen delivery while minimizing oxidative damage, the authors proposed the notion of gradually increased oxygen administration (GIOA), which entails making the arterial blood hypoxemic early in resuscitation and subsequently gradually increasing to hyperoxic, and compared its effects with normoxic resuscitation, hyperoxic resuscitation, and hypoxemic resuscitation in severe HS. Rats were subjected to HS, and on resuscitation, the rats were randomly assigned to four groups (n = 8): the normoxic, the hyperoxic, the hypoxemic, and the GIOA groups. Rats were observed for an additional 1 h. Hemodynamics, acid-base status, oxygenation, and oxidative injury were observed and evaluated. Central venous oxygen saturation promptly recovered only in the hyperoxic and the GIOA groups, and the liver tissue partial pressure of oxygen was highest in the GIOA group after resuscitation. Oxidative stress in GIOA group was significantly reduced compared with the hyperoxic group as indicated by the reduced malondialdehyde content, increased catalase activity, and the lower histologic injury scores in the liver. In addition, the tumor necrosis factor-α and interleukin-6 expressions in the liver were markedly decreased in the GIOA group than in the hyperoxic and normoxic groups as shown by the immunohistochemical staining. GIOA improved systemic/tissue oxygenation and mitigated oxidative stress simultaneously after resuscitation from severe HS. GIOA may be a promising strategy to improve resuscitation from HS and deserves further investigation.

  13. Comparison of Subset-Based Local and Finite Element-Based Global Digital Image Correlation

    KAUST Repository

    Pan, Bing; Wang, B.; Lubineau, Gilles; Moussawi, Ali

    2015-01-01

    Digital image correlation (DIC) techniques require an image matching algorithm to register the same physical points represented in different images. Subset-based local DIC and finite element-based (FE-based) global DIC are the two primary image matching methods that have been extensively investigated and regularly used in the field of experimental mechanics. Due to its straightforward implementation and high efficiency, subset-based local DIC has been used in almost all commercial DIC packages. However, it is argued by some researchers that FE-based global DIC offers better accuracy because of the enforced continuity between element nodes. We propose a detailed performance comparison between these different DIC algorithms both in terms of measurement accuracy and computational efficiency. Then, by measuring displacements of the same calculation points using the same calculation algorithms (e.g., correlation criterion, initial guess estimation, subpixel interpolation, optimization algorithm and convergence conditions) and identical calculation parameters (e.g., subset or element size), the performances of subset-based local DIC and two FE-based global DIC approaches are carefully compared in terms of measurement error and computational efficiency using both numerical tests and real experiments. A detailed examination of the experimental results reveals that, when subset (element) size is not very small and the local deformation within a subset (element) can be well approximated by the shape function used, standard subset-based local DIC approach not only provides better results in measured displacements, but also demonstrates much higher computation efficiency. However, several special merits of FE-based global DIC approaches are indicated.

  14. Comparison of Subset-Based Local and Finite Element-Based Global Digital Image Correlation

    KAUST Repository

    Pan, Bing

    2015-02-12

    Digital image correlation (DIC) techniques require an image matching algorithm to register the same physical points represented in different images. Subset-based local DIC and finite element-based (FE-based) global DIC are the two primary image matching methods that have been extensively investigated and regularly used in the field of experimental mechanics. Due to its straightforward implementation and high efficiency, subset-based local DIC has been used in almost all commercial DIC packages. However, it is argued by some researchers that FE-based global DIC offers better accuracy because of the enforced continuity between element nodes. We propose a detailed performance comparison between these different DIC algorithms both in terms of measurement accuracy and computational efficiency. Then, by measuring displacements of the same calculation points using the same calculation algorithms (e.g., correlation criterion, initial guess estimation, subpixel interpolation, optimization algorithm and convergence conditions) and identical calculation parameters (e.g., subset or element size), the performances of subset-based local DIC and two FE-based global DIC approaches are carefully compared in terms of measurement error and computational efficiency using both numerical tests and real experiments. A detailed examination of the experimental results reveals that, when subset (element) size is not very small and the local deformation within a subset (element) can be well approximated by the shape function used, standard subset-based local DIC approach not only provides better results in measured displacements, but also demonstrates much higher computation efficiency. However, several special merits of FE-based global DIC approaches are indicated.

  15. Effect of hypolimnetic oxygenation on oxygen depletion rates in two water-supply reservoirs.

    Science.gov (United States)

    Gantzer, Paul A; Bryant, Lee D; Little, John C

    2009-04-01

    Oxygenation systems, such as bubble-plume diffusers, are used to improve water quality by replenishing dissolved oxygen (DO) in the hypolimnia of water-supply reservoirs. The diffusers induce circulation and mixing, which helps distribute DO throughout the hypolimnion. Mixing, however, has also been observed to increase hypolimnetic oxygen demand (HOD) during system operation, thus accelerating oxygen depletion. Two water-supply reservoirs (Spring Hollow Reservoir (SHR) and Carvins Cove Reservoir (CCR)) that employ linear bubble-plume diffusers were studied to quantify diffuser effects on HOD. A recently validated plume model was used to predict oxygen addition rates. The results were used together with observed oxygen accumulation rates to evaluate HOD over a wide range of applied gas flow rates. Plume-induced mixing correlated well with applied gas flow rate and was observed to increase HOD. Linear relationships between applied gas flow rate and HOD were found for both SHR and CCR. HOD was also observed to be independent of bulk hypolimnion oxygen concentration, indicating that HOD is controlled by induced mixing. Despite transient increases in HOD, oxygenation caused an overall decrease in background HOD, as well as a decrease in induced HOD during diffuser operation, over several years. This suggests that the residual or background oxygen demand decreases from one year to the next. Despite diffuser-induced increases in HOD, hypolimnetic oxygenation remains a viable method for replenishing DO in thermally-stratified water-supply reservoirs such as SHR and CCR.

  16. Invariant subsets under compact quantum group actions

    OpenAIRE

    Huang, Huichi

    2012-01-01

    We investigate compact quantum group actions on unital $C^*$-algebras by analyzing invariant subsets and invariant states. In particular, we come up with the concept of compact quantum group orbits and use it to show that countable compact metrizable spaces with infinitely many points are not quantum homogeneous spaces.

  17. Two Distinct Myeloid Subsets at the Term Human Fetal–Maternal Interface

    Directory of Open Access Journals (Sweden)

    Maria Laura Costa

    2017-10-01

    Full Text Available During pregnancy, immune cells infiltrate the placenta at different stages of fetal development. NK cells and macrophages are the most predominant cell types. These immune cells play pleiotropic roles, as they control spiral artery remodeling to ensure appropriate blood supply and maintain long-term tolerance to a true allograft; yet, they must be able to mount appropriate immune defenses to pathogens that may threaten the fetus. Whether the same cell type accomplishes all these tasks or if there are dedicated subsets remains controversial. Here, we identify and characterize two distinct subsets of myeloid cells that differ in their pro-inflammatory/regulatory capacity. While one subset predominantly produces the immune-modulating cytokine IL-10, the second subset has superior capacity to secrete pro-inflammatory mediators, such as IL-1β and IL-6. The putative regulatory myeloid cells also express high levels of inhibitory receptors and their ligands, including programmed cell death 1 (PD1 ligands. Importantly, a large fraction of CD8 and CD4 cells in normal term human placenta are PD1 positive, suggesting that the PD1/PD1 ligands axis might be critical to maintain tolerance during pregnancy.

  18. Reference ranges for lymphocyte subsets in healthy adult male Oman is

    International Nuclear Information System (INIS)

    Al-Jabri, Ali A.; Al-Shukaili, Ahmed K.; Al-Rashdi, Zowaina T.; Ganguly, Shyam S.

    2008-01-01

    Objective was to determine the reference ranges of lymphocyte subsets in serologically HIV-seronegative healthy male adults in Oman. A cohort, of 118 healthy male blood donors ranging in age from 18-51 years, was included in the study. The average was 25 years. Blood samples collected into tubes containing ethylene-diamine-tetra acetic acid were investigated for lymphocyte subsets using flow cytometer. This study was conducted in the Immunology Laboratory of Sultan Qaboos University, College of Medicine and Health Sciences, Muscat, Oman during the year 2006. For the 118 males investigated, the mean percentage and absolute values of the lymphocyte subsets were as follows: Cd3: 68.53+-7.5%, 1701+-489 cells/ul; CD8: 25.8+-5.9%, 638+-225 cells/ul; CD19: 13.7+-4.7%, 349+-158 cells/ul, CD56: 12.2+-6.7%, 308+-204 cells/ul. The ratio of CD4/CD8 was 1.6. Immunophenotyping has been used to establish reference values of lymphocyte subsets in normal healthy adult males in Oman. The Omani male reference values obtained in this study show wide variations compared with kits values previously used as reference. (author)

  19. Mechanism of singlet oxygen deactivation in an electric discharge oxygen – iodine laser

    Energy Technology Data Exchange (ETDEWEB)

    Azyazov, V N; Mikheyev, P A; Torbin, A P [Samara Branch of the P.N. Lebedev Physical Institute, Russian Academy of Sciences, Samara (Russian Federation); Pershin, A A [S.P. Korolev Samara State Aerospace University, Samara (Russian Federation); Heaven, M C [Emory University, Atlanta, GA, 30322 (United States)

    2014-12-31

    We have determined the influence of the reaction of molecular singlet oxygen with a vibrationally excited ozone molecule O{sub 2}(a {sup 1}Δ) + O{sub 3}(ν) → 2O{sub 2} + O on the removal rate of O{sub 2}(a {sup 1}Δ) in an electric-discharge-driven oxygen – iodine laser. This reaction has been shown to be a major channel of O{sub 2}(a {sup 1}Δ) loss at the output of an electric-discharge singlet oxygen generator. In addition, it can also contribute significantly to the loss of O{sub 2}(a {sup 1}Δ) in the discharge region of the generator. (lasers)

  20. Two-stage atlas subset selection in multi-atlas based image segmentation

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Tingting, E-mail: tingtingzhao@mednet.ucla.edu; Ruan, Dan, E-mail: druan@mednet.ucla.edu [The Department of Radiation Oncology, University of California, Los Angeles, California 90095 (United States)

    2015-06-15

    Purpose: Fast growing access to large databases and cloud stored data presents a unique opportunity for multi-atlas based image segmentation and also presents challenges in heterogeneous atlas quality and computation burden. This work aims to develop a novel two-stage method tailored to the special needs in the face of large atlas collection with varied quality, so that high-accuracy segmentation can be achieved with low computational cost. Methods: An atlas subset selection scheme is proposed to substitute a significant portion of the computationally expensive full-fledged registration in the conventional scheme with a low-cost alternative. More specifically, the authors introduce a two-stage atlas subset selection method. In the first stage, an augmented subset is obtained based on a low-cost registration configuration and a preliminary relevance metric; in the second stage, the subset is further narrowed down to a fusion set of desired size, based on full-fledged registration and a refined relevance metric. An inference model is developed to characterize the relationship between the preliminary and refined relevance metrics, and a proper augmented subset size is derived to ensure that the desired atlases survive the preliminary selection with high probability. Results: The performance of the proposed scheme has been assessed with cross validation based on two clinical datasets consisting of manually segmented prostate and brain magnetic resonance images, respectively. The proposed scheme demonstrates comparable end-to-end segmentation performance as the conventional single-stage selection method, but with significant computation reduction. Compared with the alternative computation reduction method, their scheme improves the mean and medium Dice similarity coefficient value from (0.74, 0.78) to (0.83, 0.85) and from (0.82, 0.84) to (0.95, 0.95) for prostate and corpus callosum segmentation, respectively, with statistical significance. Conclusions: The authors

  1. Two-stage atlas subset selection in multi-atlas based image segmentation.

    Science.gov (United States)

    Zhao, Tingting; Ruan, Dan

    2015-06-01

    Fast growing access to large databases and cloud stored data presents a unique opportunity for multi-atlas based image segmentation and also presents challenges in heterogeneous atlas quality and computation burden. This work aims to develop a novel two-stage method tailored to the special needs in the face of large atlas collection with varied quality, so that high-accuracy segmentation can be achieved with low computational cost. An atlas subset selection scheme is proposed to substitute a significant portion of the computationally expensive full-fledged registration in the conventional scheme with a low-cost alternative. More specifically, the authors introduce a two-stage atlas subset selection method. In the first stage, an augmented subset is obtained based on a low-cost registration configuration and a preliminary relevance metric; in the second stage, the subset is further narrowed down to a fusion set of desired size, based on full-fledged registration and a refined relevance metric. An inference model is developed to characterize the relationship between the preliminary and refined relevance metrics, and a proper augmented subset size is derived to ensure that the desired atlases survive the preliminary selection with high probability. The performance of the proposed scheme has been assessed with cross validation based on two clinical datasets consisting of manually segmented prostate and brain magnetic resonance images, respectively. The proposed scheme demonstrates comparable end-to-end segmentation performance as the conventional single-stage selection method, but with significant computation reduction. Compared with the alternative computation reduction method, their scheme improves the mean and medium Dice similarity coefficient value from (0.74, 0.78) to (0.83, 0.85) and from (0.82, 0.84) to (0.95, 0.95) for prostate and corpus callosum segmentation, respectively, with statistical significance. The authors have developed a novel two-stage atlas

  2. Two-stage atlas subset selection in multi-atlas based image segmentation

    International Nuclear Information System (INIS)

    Zhao, Tingting; Ruan, Dan

    2015-01-01

    Purpose: Fast growing access to large databases and cloud stored data presents a unique opportunity for multi-atlas based image segmentation and also presents challenges in heterogeneous atlas quality and computation burden. This work aims to develop a novel two-stage method tailored to the special needs in the face of large atlas collection with varied quality, so that high-accuracy segmentation can be achieved with low computational cost. Methods: An atlas subset selection scheme is proposed to substitute a significant portion of the computationally expensive full-fledged registration in the conventional scheme with a low-cost alternative. More specifically, the authors introduce a two-stage atlas subset selection method. In the first stage, an augmented subset is obtained based on a low-cost registration configuration and a preliminary relevance metric; in the second stage, the subset is further narrowed down to a fusion set of desired size, based on full-fledged registration and a refined relevance metric. An inference model is developed to characterize the relationship between the preliminary and refined relevance metrics, and a proper augmented subset size is derived to ensure that the desired atlases survive the preliminary selection with high probability. Results: The performance of the proposed scheme has been assessed with cross validation based on two clinical datasets consisting of manually segmented prostate and brain magnetic resonance images, respectively. The proposed scheme demonstrates comparable end-to-end segmentation performance as the conventional single-stage selection method, but with significant computation reduction. Compared with the alternative computation reduction method, their scheme improves the mean and medium Dice similarity coefficient value from (0.74, 0.78) to (0.83, 0.85) and from (0.82, 0.84) to (0.95, 0.95) for prostate and corpus callosum segmentation, respectively, with statistical significance. Conclusions: The authors

  3. Complete synchronization of chaotic atmospheric models by connecting only a subset of state space

    Directory of Open Access Journals (Sweden)

    P. H. Hiemstra

    2012-11-01

    Full Text Available Connected chaotic systems can, under some circumstances, synchronize their states with an exchange of matter and energy between the systems. This is the case for toy models like the Lorenz 63, and more complex models. In this study we perform synchronization experiments with two connected quasi-geostrophic (QG models of the atmosphere with 1449 degrees of freedom. The purpose is to determine whether connecting only a subset of the model state space can still lead to complete synchronization (CS. In addition, we evaluated whether empirical orthogonal functions (EOF form efficient basis functions for synchronization in order to limit the number of connections. In this paper, we show that only the intermediate spectral wavenumbers (5–12 need to be connected in order to achieve CS. In addition, the minimum connection timescale needed for CS is 7.3 days. Both the connection subset and the connection timescale, or strength, are consistent with the time and spatial scales of the baroclinic instabilities in the model. This is in line with the fact that the baroclinic instabilities are the largest source of divergence between the two connected models. Using the Lorenz 63 model, we show that EOFs are nearly optimal basis functions for synchronization. The QG model results show that the minimum number of EOFs that need to be connected for CS is a factor of three smaller than when connecting the original state variables.

  4. Influence of kaolin addition on the dynamics of oxygen mass transport in polyvinyl alcohol dispersion coatings

    OpenAIRE

    Nyflött, Åsa; Axrup, Lars; Gunilla, Carlsson; Järnström, Lars; Lestelius, Magnus; Moons, Ellen; Wahlström, Torbjörn

    2015-01-01

    The permeability of dispersion barriers produced from polyvinyl alcohol (PVOH) and kaolin clay blends coated onto polymeric supports has been studied by employing two different measurement methods: the oxygen transmission rate (OTR) and the ambient oxygen ingress rate (AOIR). Coatings with different thicknesses and kaolin contents were studied. Structural information of the dispersion-barrier coatings was obtained by Fourier transform infrared spectroscopy (FTIR) spectroscopy and scanning ele...

  5. Oxygen tension level and human viral infections

    Energy Technology Data Exchange (ETDEWEB)

    Morinet, Frédéric, E-mail: frederic.morinet@sls.aphp.fr [Centre des Innovations Thérapeutiques en Oncologie et Hématologie (CITOH), CHU Saint-Louis, Paris (France); Université Denis Diderot, Sorbonne Paris Cité Paris, Paris (France); Casetti, Luana [Institut Cochin INSERM U1016, Paris (France); François, Jean-Hugues; Capron, Claude [Institut Cochin INSERM U1016, Paris (France); Laboratoire d' Hématologie, Hôpital Ambroise Paré, Boulogne (France); Université de Versailles Saint-Quentin en Yvelynes, Versailles (France); Pillet, Sylvie [Laboratoire de Bactériologie-Virologie-Hygiène, CHU de Saint-Etienne, Saint-Etienne (France); Université de Lyon et Université de Saint-Etienne, Jean Monnet, GIMAP EA3064, F-42023 Saint-Etienne, Lyon (France)

    2013-09-15

    The role of oxygen tension level is a well-known phenomenon that has been studied in oncology and radiotherapy since about 60 years. Oxygen tension may inhibit or stimulate propagation of viruses in vitro as well as in vivo. In turn modulating oxygen metabolism may constitute a novel approach to treat viral infections as an adjuvant therapy. The major transcription factor which regulates oxygen tension level is hypoxia-inducible factor-1 alpha (HIF-1α). Down-regulating the expression of HIF-1α is a possible method in the treatment of chronic viral infection such as human immunodeficiency virus infection, chronic hepatitis B and C viral infections and Kaposi sarcoma in addition to classic chemotherapy. The aim of this review is to supply an updating concerning the influence of oxygen tension level in human viral infections and to evoke possible new therapeutic strategies regarding this environmental condition. - Highlights: • Oxygen tension level regulates viral replication in vitro and possibly in vivo. • Hypoxia-inducible factor 1 (HIF-1α) is the principal factor involved in Oxygen tension level. • HIF-1α upregulates gene expression for example of HIV, JC and Kaposi sarcoma viruses. • In addition to classical chemotherapy inhibition of HIF-1α may constitute a new track to treat human viral infections.

  6. Micro-oxygenation of red wine: techniques, applications, and outcomes.

    Science.gov (United States)

    Schmidtke, Leigh M; Clark, Andrew C; Scollary, Geoff R

    2011-02-01

    Wine micro-oxygenation (MOX) is the controlled addition of oxygen to wine in a manner designed to ensure that complete mass transfer of molecular oxygen from gaseous to dissolved state occurs. MOX was initially developed to improve the body, structure, and fruitfulness in red wines with high concentrations of tannins and anthocyanins, by replicating the ingress of oxygen thought to arise from barrel maturation, but without the need for putting all wine to barrel. This review describes the operational parameters essential for the effective performance of the micro-oxidation process as well as the chemical and microbiological outcomes. The methodologies for introducing oxygen into the wine, the rates of oxygen addition, and their relationship to oxygen solubility in the wine matrix are examined. The review focuses on the techniques used for monitoring the MOX process, including sensory assessment, physicochemical properties, and the critical balance of the rate of oxygen addition in relation to maintaining the sulfur dioxide concentration. The chemistry of oxygen reactivity with wine components, the changes in wine composition that occur as a consequence of MOX, and the potential for wine spoilage if proper monitoring is not adopted are examined. Gaps in existing knowledge are addressed focusing on the limitations associated with the transfer of concepts from research trials in small volume tanks to commercial practice, and the dearth of kinetic data for the various chemical and physical processes that are claimed to occur during MOX.

  7. Clinically Relevant Subsets Identified by Gene Expression Patterns Support a Revised Ontogenic Model of Wilms Tumor: A Children's Oncology Group Study

    Directory of Open Access Journals (Sweden)

    Samantha Gadd

    2012-08-01

    Full Text Available Wilms tumors (WT have provided broad insights into the interface between development and tumorigenesis. Further understanding is confounded by their genetic, histologic, and clinical heterogeneity, the basis of which remains largely unknown. We evaluated 224 WT for global gene expression patterns; WT1, CTNNB1, and WTX mutation; and 11p15 copy number and methylation patterns. Five subsets were identified showing distinct differences in their pathologic and clinical features: these findings were validated in 100 additional WT. The gene expression pattern of each subset was compared with published gene expression profiles during normal renal development. A novel subset of epithelial WT in infants lacked WT1, CTNNB1, and WTX mutations and nephrogenic rests and displayed a gene expression pattern of the postinduction nephron, and none recurred. Three subsets were characterized by a low expression of WT1 and intralobar nephrogenic rests. These differed in their frequency of WT1 and CTNNB1 mutations, in their age, in their relapse rate, and in their expression similarities with the intermediate mesoderm versus the metanephric mesenchyme. The largest subset was characterized by biallelic methylation of the imprint control region 1, a gene expression profile of the metanephric mesenchyme, and both interlunar and perilobar nephrogenic rests. These data provide a biologic explanation for the clinical and pathologic heterogeneity seen within WT and enable the future development of subset-specific therapeutic strategies. Further, these data support a revision of the current model of WT ontogeny, which allows for an interplay between the type of initiating event and the developmental stage in which it occurs.

  8. Lithium-Oxygen Batteries: At a Crossroads?

    DEFF Research Database (Denmark)

    Vegge, Tejs; García Lastra, Juan Maria; Siegel, Donald Jason

    2017-01-01

    In this current opinion, we critically review and discuss some of the most important recent findings in the field of rechargeable lithium-oxygen batteries. We discuss recent discoveries like the evolution of reactive singlet oxygen and the use of organic additives to bypass reactive LiO2 reaction...... intermediates, and their possible implications on the potential for commercialization of lithium-oxygen batteries. Finally, we perform a critical assessment of lithium-superoxide batteries and the reversibility of lithium-hydroxide batteries....

  9. Simultaneous determination of oxygen and cadmium in cadmium and cadmium compounds

    International Nuclear Information System (INIS)

    Imaeda, K.; Kuriki, T.; Ohsawa, K.; Ishii, Y.

    1977-01-01

    Cadmium and its compounds were analysed for oxygen and cadmium by a modification of the Schutze-Unterzaucher method. Oxygen in some compounds such as cadmium oxide, nitrate and sulphate could not be determined by the usual method. The method of adding carbon was employed for the determination of total oxygen. Total oxygen could be determined by the addition of 5 mg of carbon to a sample boat and heating at 950 0 . The determination was also carried out by addition of naphthalene (2 mg). It was found that the cadmium powder and cadmium flake used contained ca. 1 and 0.15% oxygen, respectively. Oxygen and cadmium in cadmium and its compounds were simultaneously determined by the addition of 2 mg of naphthalene. Cadmium was determined colorimetrically by use of glyoxal-bis-(2-hydroxyanil). Oxygen and cadmium in the samples could be determined simultaneously with an average error of -0.02 and -0.22%, respectively. (author)

  10. Range-reference determination of lymphocyte subsets in Moroccan

    African Journals Online (AJOL)

    Administrator

    Centre de Transfusion Sanguine, Hôpital Militaire d'Instruction Med V Rabat, Morocco. 3. Service ... The percentage of CD3-CD56+ subsets was affected by smoking (p < 0.01). Our analysis .... lymphocyte subpopulations in non-smokers and.

  11. Effects of organic additives with oxygen- and nitrogen-containing functional groups on the negative electrolyte of vanadium redox flow battery

    International Nuclear Information System (INIS)

    Liu, Jianlei; Liu, Suqin; He, Zhangxing; Han, Huiguo; Chen, Yong

    2014-01-01

    DL-malic acid and L-aspartic acid are investigated as additives for the negative electrolyte of vanadium redox flow battery (VFRB) to improve its stability and electrochemical performance. The stability experiments indicate that the addition of L-aspartic acid into the 2 M V(III) electrolyte can stabilize the electrolyte by delaying its precipitation. The results of cyclic voltammetry and electrochemical impedance spectroscopy show that the V(III) electrolyte with both additives demonstrates enhanced electrochemical activity and reversibility. The introduction of DL-malic acid and L-aspartic acid can increase the diffusion coefficient of V(III) species and facilitate the charge transfer of V(III)/V(II) redox reaction. Between the two additives, the effect of L-aspartic acid is more remarkable. Moreover, the VFRB cell employing negative electrolyte with L-aspartic acid exhibits excellent cycling stability and achieves higher average energy efficiency (76.4%) compared to the pristine cell (73.8%). The comparison results with the cell employing L-aspartic acid pre-treated electrode confirm that L-aspartic acid in the electrolyte can modify the electrode by constantly providing oxygen- and nitrogen-containing groups, leading to the enhancement of electrochemical performance

  12. Auditing Complex Concepts in Overlapping Subsets of SNOMED

    Science.gov (United States)

    Wang, Yue; Wei, Duo; Xu, Junchuan; Elhanan, Gai; Perl, Yehoshua; Halper, Michael; Chen, Yan; Spackman, Kent A.; Hripcsak, George

    2008-01-01

    Limited resources and the sheer volume of concepts make auditing a large terminology, such as SNOMED CT, a daunting task. It is essential to devise techniques that can aid an auditor by automatically identifying concepts that deserve attention. A methodology for this purpose based on a previously introduced abstraction network (called the p-area taxonomy) for a SNOMED CT hierarchy is presented. The methodology algorithmically gathers concepts appearing in certain overlapping subsets, defined exclusively with respect to the p-area taxonomy, for review. The results of applying the methodology to SNOMED’s Specimen hierarchy are presented. These results are compared against a control sample composed of concepts residing in subsets without the overlaps. With the use of the double bootstrap, the concept group produced by our methodology is shown to yield a statistically significant higher proportion of error discoveries. PMID:18998838

  13. Adenovirus-specific T-cell Subsets in Human Peripheral Blood and After IFN-γ Immunomagnetic Selection.

    Science.gov (United States)

    Qian, Chongsheng; Wang, Yingying; Cai, Huili; Laroye, Caroline; De Carvalho Bittencourt, Marcelo; Clement, Laurence; Stoltz, Jean-François; Decot, Véronique; Reppel, Loïc; Bensoussan, Danièle

    2016-01-01

    Adoptive antiviral cellular immunotherapy by infusion of virus-specific T cells (VSTs) is becoming an alternative treatment for viral infection after hematopoietic stem cell transplantation. The T memory stem cell (TSCM) subset was recently described as exhibiting self-renewal and multipotency properties which are required for sustained efficacy in vivo. We wondered if such a crucial subset for immunotherapy was present in VSTs. We identified, by flow cytometry, TSCM in adenovirus (ADV)-specific interferon (IFN)-γ+ T cells before and after IFN-γ-based immunomagnetic selection, and analyzed the distribution of the main T-cell subsets in VSTs: naive T cells (TN), TSCM, T central memory cells (TCM), T effector memory cell (TEM), and effector T cells (TEFF). In this study all of the different T-cell subsets were observed in the blood sample from healthy donor ADV-VSTs, both before and after IFN-γ-based immunomagnetic selection. As the IFN-γ-based immunomagnetic selection system sorts mainly the most differentiated T-cell subsets, we observed that TEM was always the major T-cell subset of ADV-specific T cells after immunomagnetic isolation and especially after expansion in vitro. Comparing T-cell subpopulation profiles before and after in vitro expansion, we observed that in vitro cell culture with interleukin-2 resulted in a significant expansion of TN-like, TCM, TEM, and TEFF subsets in CD4IFN-γ T cells and of TCM and TEM subsets only in CD8IFN-γ T cells. We demonstrated the presence of all T-cell subsets in IFN-γ VSTs including the TSCM subpopulation, although this was weakly selected by the IFN-γ-based immunomagnetic selection system.

  14. Medical oxygen and air travel.

    Science.gov (United States)

    Lyznicki, J M; Williams, M A; Deitchman, S D; Howe, J P

    2000-08-01

    This report responds to a resolution that asked the American Medical Association (AMA) to take action to improve airport and airline accommodations for passengers requiring medical oxygen. Information for the report was derived from a search of the MEDLINE database and references listed in pertinent articles, as well as through communications with experts in aerospace and emergency medicine. Based on this information, the AMA Council on Scientific Affairs determined that commercial air travel exposes passengers to altitude-related hypoxia and gas expansion, which may cause some passengers to experience significant symptoms and medical complications during flight. Medical guidelines are available to help physicians evaluate and counsel potential passengers who are at increased risk of inflight hypoxemia. Supplemental oxygen may be needed for some passengers to maintain adequate tissue oxygenation and prevent hypoxemic complications. For safety and security reasons, federal regulations prohibit travelers from using their own portable oxygen system onboard commercial aircraft. Many U.S. airlines supply medical oxygen for use during flight but policies and procedures vary. Oxygen-dependent passengers must make additional arrangements for the use of supplemental oxygen in airports. Uniform standards are needed to specify procedures and equipment for the use of medical oxygen in airports and aboard commercial aircraft. Revision of federal regulations should be considered to accommodate oxygen-dependent passengers and permit them to have an uninterrupted source of oxygen from departure to destination.

  15. Hyperbaric Oxygen Therapy and Oxygen Compatibility of Skin and Wound Care Products.

    Science.gov (United States)

    Bernatchez, Stéphanie F; Tucker, Joseph; Chiffoleau, Gwenael

    2017-11-01

    Objective: Use test methods to assess the oxygen compatibility of various wound care products. Approach: There are currently no standard test methods specifically for evaluating the oxygen compatibility and safety of materials under hyperbaric oxygen (HBO) conditions. However, tests such as the oxygen index (OI), oxygen exposure (OE), and autogenous ignition temperature (AIT) can provide useful information. Results: The OI test measures the minimum oxygen concentration that will support candle-like burning, and it was used to test 44 materials. All but two exhibited an OI equal to or greater (safer) than a control material commonly used in HBO. The OE test exposes each material to an oxygen-enriched atmosphere (>99.5% oxygen) to monitor temperature and pressure for an extended duration. The results of the OE testing indicated that none of the 44 articles tested with this method self-ignited within the 60°C, 3 atm pressurized oxygen atmosphere. The AIT test exposes materials to a rapid ramp up in temperature in HBO conditions at 3 atm until ignition occurs. Ten wound care materials and seven materials usually avoided in HBO chambers were tested. The AIT ranged from 138°C to 384°C for wound care products and from 146°C to 420°C for the other materials. Innovation: This work provides useful data and recommendations to help develop a new standard approach for evaluating the HBO compatibility of wound care products to ensure safety for patients and clinicians. Conclusion: The development of an additional test to measure the risk of electrostatic discharge of materials in HBO conditions is needed.

  16. Subset Statistics in the linear IV regression model

    NARCIS (Netherlands)

    Kleibergen, F.R.

    2005-01-01

    We show that the limiting distributions of subset generalizations of the weak instrument robust instrumental variable statistics are boundedly similar when the remaining structural parameters are estimated using maximum likelihood. They are bounded from above by the limiting distributions which

  17. Factors Determining the Oxygen Permeability of Biological Membranes: Oxygen Transport Across Eye Lens Fiber-Cell Plasma Membranes.

    Science.gov (United States)

    Subczynski, Witold Karol; Widomska, Justyna; Mainali, Laxman

    2017-01-01

    Electron paramagnetic resonance (EPR) spin-label oximetry allows the oxygen permeability coefficient to be evaluated across homogeneous lipid bilayer membranes and, in some cases, across coexisting membrane domains without their physical separation. The most pronounced effect on oxygen permeability is observed for cholesterol, which additionally induces the formation of membrane domains. In intact biological membranes, integral proteins induce the formation of boundary and trapped lipid domains with a low oxygen permeability. The effective oxygen permeability coefficient across the intact biological membrane is affected not only by the oxygen permeability coefficients evaluated for each lipid domain but also by the surface area occupied by these domains in the membrane. All these factors observed in fiber cell plasma membranes of clear human eye lenses are reviewed here.

  18. There is a need for new systemic sclerosis subset criteria. A content analytic approach.

    Science.gov (United States)

    Johnson, S R; Soowamber, M L; Fransen, J; Khanna, D; Van Den Hoogen, F; Baron, M; Matucci-Cerinic, M; Denton, C P; Medsger, T A; Carreira, P E; Riemekasten, G; Distler, J; Gabrielli, A; Steen, V; Chung, L; Silver, R; Varga, J; Müller-Ladner, U; Vonk, M C; Walker, U A; Wollheim, F A; Herrick, A; Furst, D E; Czirjak, L; Kowal-Bielecka, O; Del Galdo, F; Cutolo, M; Hunzelmann, N; Murray, C D; Foeldvari, I; Mouthon, L; Damjanov, N; Kahaleh, B; Frech, T; Assassi, S; Saketkoo, L A; Pope, J E

    2018-01-01

    Systemic sclerosis (SSc) is heterogenous. The objectives of this study were to evaluate the purpose, strengths and limitations of existing SSc subset criteria, and identify ideas among experts about subsets. We conducted semi-structured interviews with randomly sampled international SSc experts. The interview transcripts underwent an iterative process with text deconstructed to single thought units until a saturated conceptual framework with coding was achieved and respondent occurrence tabulated. Serial cross-referential analyses of clusters were developed. Thirty experts from 13 countries were included; 67% were male, 63% were from Europe and 37% from North America; median experience of 22.5 years, with a median of 55 new SSc patients annually. Three thematic clusters regarding subsetting were identified: research and communication; management; and prognosis (prediction of internal organ involvement, survival). The strength of the limited/diffuse system was its ease of use, however 10% stated this system had marginal value. Shortcomings of the diffuse/limited classification were the risk of misclassification, predictions/generalizations did not always hold true, and that the elbow or knee threshold was arbitrary. Eighty-seven percent use more than 2 subsets including: SSc sine scleroderma, overlap conditions, antibody-determined subsets, speed of progression, and age of onset (juvenile, elderly). We have synthesized an international view of the construct of SSc subsets in the modern era. We found a number of factors underlying the construct of SSc subsets. Considerations for the next phase include rate of change and hierarchal clustering (e.g. limited/diffuse, then by antibodies).

  19. Selecting Optimal Subset of Security Controls

    OpenAIRE

    Yevseyeva, I.; Basto-Fernandes, V.; Michael, Emmerich, T. M.; Moorsel, van, A.

    2015-01-01

    Open Access journal Choosing an optimal investment in information security is an issue most companies face these days. Which security controls to buy to protect the IT system of a company in the best way? Selecting a subset of security controls among many available ones can be seen as a resource allocation problem that should take into account conflicting objectives and constraints of the problem. In particular, the security of the system should be improved without hindering productivity, ...

  20. Oxygen potentials, oxygen diffusion coefficients and defect equilibria of nonstoichiometric (U,Pu)O{sub 2±x}

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Masato, E-mail: kato.masato@jaea.go.jp [Fukushima Fuels and Materials Department, Japan Atomic Energy Agency, 4002 Narita-chou, O-arai machi, Ibaraki 311-1919 (Japan); Fast Reactor Fuel Cycle Technology Development Division, Japan Atomic Energy Agency, 4-33 Muramatsu Tokai-mura, Ibaraki 319-1194 (Japan); Watanabe, Masashi [Fukushima Fuels and Materials Department, Japan Atomic Energy Agency, 4002 Narita-chou, O-arai machi, Ibaraki 311-1919 (Japan); Fast Reactor Fuel Cycle Technology Development Division, Japan Atomic Energy Agency, 4-33 Muramatsu Tokai-mura, Ibaraki 319-1194 (Japan); Matsumoto, Taku; Hirooka, Shun; Akashi, Masatoshi [Fast Reactor Fuel Cycle Technology Development Division, Japan Atomic Energy Agency, 4-33 Muramatsu Tokai-mura, Ibaraki 319-1194 (Japan)

    2017-04-15

    Oxygen potential of (U,Pu)O{sub 2±x} was evaluated based on defect chemistry using an updated experimental data set. The relationship between oxygen partial pressure and deviation x in (U,Pu)O{sub 2±x} was analyzed, and equilibrium constants of defect formation were determined as functions of Pu content and temperature. Brouwer's diagrams were constructed using the determined equilibrium constants, and a relational equation to determine O/M ratio was derived as functions of O/M ratio, Pu content and temperature. In addition, relationship between oxygen potential and oxygen diffusion coefficients were described. - Highlights: •Brouwer’s diagrams for (U,Pu)O2 were constructed using the updated oxygen potential experimental data set. •Equilibrium constants of defect formation were determined as functions of Pu content and temperature. •Oxygen potential, oxygen diffusion coefficients, point defect concentration were described as functions of O/M ratio, Pu content and temperature.

  1. Selection of a representative subset of global climate models that captures the profile of regional changes for integrated climate impacts assessment

    Directory of Open Access Journals (Sweden)

    Alex C. Ruane

    2017-03-01

    Full Text Available Abstract We present the Representative Temperature and Precipitation (T&P GCM Subsetting Approach developed within the Agricultural Model Intercomparison and Improvement Project (AgMIP to select a practical subset of global climate models (GCMs for regional integrated assessment of climate impacts when resource limitations do not permit the full ensemble of GCMs to be evaluated given the need to also focus on impacts sector and economics models. Subsetting inherently leads to a loss of information but can free up resources to explore important uncertainties in the integrated assessment that would otherwise be prohibitive. The Representative T&P GCM Subsetting Approach identifies five individual GCMs that capture a profile of the full ensemble of temperature and precipitation change within the growing season while maintaining information about the probability that basic classes of climate changes (relatively cool/wet, cool/dry, middle, hot/wet, and hot/dry are projected in the full GCM ensemble. We demonstrate the selection methodology for maize impacts in Ames, Iowa, and discuss limitations and situations when additional information may be required to select representative GCMs. We then classify 29 GCMs over all land areas to identify regions and seasons with characteristic diagonal skewness related to surface moisture as well as extreme skewness connected to snow-albedo feedbacks and GCM uncertainty. Finally, we employ this basic approach to recognize that GCM projections demonstrate coherence across space, time, and greenhouse gas concentration pathway. The Representative T&P GCM Subsetting Approach provides a quantitative basis for the determination of useful GCM subsets, provides a practical and coherent approach where previous assessments selected solely on availability of scenarios, and may be extended for application to a range of scales and sectoral impacts.

  2. B cell subset distribution is altered in patients with severe periodontitis.

    Science.gov (United States)

    Demoersman, Julien; Pochard, Pierre; Framery, Camille; Simon, Quentin; Boisramé, Sylvie; Soueidan, Assem; Pers, Jacques-Olivier

    2018-01-01

    Several studies have recently highlighted the implication of B cells in physiopathogenesis of periodontal disease by showing that a B cell deficiency leads to improved periodontal parameters. However, the detailed profiles of circulating B cell subsets have not yet been investigated in patients with severe periodontitis (SP). We hypothesised that an abnormal distribution of B cell subsets could be detected in the blood of patients with severe periodontal lesions, as already reported for patients with chronic inflammatory diseases as systemic autoimmune diseases. Fifteen subjects with SP and 13 subjects without periodontitis, according to the definition proposed by the CDC periodontal disease surveillance work group, were enrolled in this pilot observational study. Two flow cytometry panels were designed to analyse the circulating B and B1 cell subset distribution in association with the RANKL expression. A significantly higher percentage of CD27+ memory B cells was observed in patients with SP. Among these CD27+ B cells, the proportion of the switched memory subset was significantly higher. At the same time, human B1 cells, which were previously associated with a regulatory function (CD20+CD69-CD43+CD27+CD11b+), decreased in SP patients. The RANKL expression increased in every B cell subset from the SP patients and was significantly greater in activated B cells than in the subjects without periodontitis. These preliminary results demonstrate the altered distribution of B cells in the context of severe periodontitis. Further investigations with a larger cohort of patients can elucidate if the analysis of the B cell compartment distribution can reflect the periodontal disease activity and be a reliable marker for its prognosis (clinical trial registration number: NCT02833285, B cell functions in periodontitis).

  3. B cell subset distribution is altered in patients with severe periodontitis

    Science.gov (United States)

    Demoersman, Julien; Pochard, Pierre; Framery, Camille; Simon, Quentin; Boisramé, Sylvie; Soueidan, Assem

    2018-01-01

    Several studies have recently highlighted the implication of B cells in physiopathogenesis of periodontal disease by showing that a B cell deficiency leads to improved periodontal parameters. However, the detailed profiles of circulating B cell subsets have not yet been investigated in patients with severe periodontitis (SP). We hypothesised that an abnormal distribution of B cell subsets could be detected in the blood of patients with severe periodontal lesions, as already reported for patients with chronic inflammatory diseases as systemic autoimmune diseases. Fifteen subjects with SP and 13 subjects without periodontitis, according to the definition proposed by the CDC periodontal disease surveillance work group, were enrolled in this pilot observational study. Two flow cytometry panels were designed to analyse the circulating B and B1 cell subset distribution in association with the RANKL expression. A significantly higher percentage of CD27+ memory B cells was observed in patients with SP. Among these CD27+ B cells, the proportion of the switched memory subset was significantly higher. At the same time, human B1 cells, which were previously associated with a regulatory function (CD20+CD69-CD43+CD27+CD11b+), decreased in SP patients. The RANKL expression increased in every B cell subset from the SP patients and was significantly greater in activated B cells than in the subjects without periodontitis. These preliminary results demonstrate the altered distribution of B cells in the context of severe periodontitis. Further investigations with a larger cohort of patients can elucidate if the analysis of the B cell compartment distribution can reflect the periodontal disease activity and be a reliable marker for its prognosis (clinical trial registration number: NCT02833285, B cell functions in periodontitis). PMID:29447240

  4. Lymphocyte subset contents in cerebrospinal fluid of children with viral encephalitis

    Directory of Open Access Journals (Sweden)

    An-Ran Xu

    2016-06-01

    Full Text Available Objective: To study the lymphocyte subset contents in cerebrospinal fluid of children with viral encephalitis and their correlation with disease. Methods: Children with viral encephalitis were selected as VE group, children excluded of central nervous system infection by lumbar puncture or children without central nervous system diseases but receiving surgery with spinal anesthesia were selected as control group, and then cerebrospinal fluid and serum were collected to detect lymphocyte subset contents, nerve injury molecule contents as well as inflammatory response indicators and oxidative stress response indicators. Results: CD3+, CD3+CD4+, CD4/CD8 and CD16+CD56+ in cerebrospinal fluid of VE group were lower than those of control group, and both CD3+CD8+ and CD19+ were higher than those of control group; CD3+, CD3+CD4+, CD4/CD8 and CD16+CD56+ in cerebrospinal fluid of children with abnormal MRI were lower than those of children with normal MRI, and both CD3+CD8+ and CD19+ were higher than those of children with normal MRI; NSE, MBP, S-100 and NPT contents in cerebrospinal fluid and serum of VE group were significantly higher than those of control group and had good correlation with lymphocyte subset contents; MMP9, TNF-α and IL-6 contents in cerebrospinal fluid of VE group were significantly higher than those of control group, and SOD and GSH-Px contents were significantly lower than those of control group and had good correlation with lymphocyte subset contents. Conclusions: CD4+/CD8+T lymphocyte ratio and NK cell content decrease, and B lymphocyte content increases in cerebrospinal fluid of children with viral encephalitis, and lymphocyte subset contents have inhibitory effect on MRI manifestation, degree of inflammatory response and oxidative stress response.

  5. Implementing Modifed Burg Algorithms in Multivariate Subset Autoregressive Modeling

    Directory of Open Access Journals (Sweden)

    A. Alexandre Trindade

    2003-02-01

    Full Text Available The large number of parameters in subset vector autoregressive models often leads one to procure fast, simple, and efficient alternatives or precursors to maximum likelihood estimation. We present the solution of the multivariate subset Yule-Walker equations as one such alternative. In recent work, Brockwell, Dahlhaus, and Trindade (2002, show that the Yule-Walker estimators can actually be obtained as a special case of a general recursive Burg-type algorithm. We illustrate the structure of this Algorithm, and discuss its implementation in a high-level programming language. Applications of the Algorithm in univariate and bivariate modeling are showcased in examples. Univariate and bivariate versions of the Algorithm written in Fortran 90 are included in the appendix, and their use illustrated.

  6. Characteristics of CD8+ T cell subsets in Chinese patients with chronic HIV infection during initial ART.

    Science.gov (United States)

    Jiao, Yanmei; Hua, Wei; Zhang, Tong; Zhang, Yonghong; Ji, Yunxia; Zhang, Hongwei; Wu, Hao

    2011-03-25

    CD8+ T cells may play an important role in protecting against HIV. However, the changes of CD8+ T cell subsets during early period of ART have not been fully studied. Twenty-one asymptomatic treatment-naive HIV-infected patients with CD4 T+ cells less than 350 cells/μl were enrolled in the study. Naïve, central memory(CM), effective memory(EM) and terminally differentiated effector (EMRA) CD8+ cell subsets and their activation and proliferation subsets were evaluated in blood samples collected at base line, and week 2, 4, 8 and 12 of ART. The total CD8+ T cells declined and the Naïve and CM subsets had a tendency of increase. Activation levels of all CD8+ T cell subsets except EMRA subset decreased after ART. However, proliferation levels of total CD8+ T cells, EMRA, EM and CM subsets increased at the first 4 weeks of ART, then decreased. Proliferation level of the naïve cells decreased after ART. The changes of CD8+ T cell subsets during initial ART are complex. Our results display a complete phenotypical picture of CD8+ cell subsets during initial ART and provide insights for understanding of immune status during ART.

  7. Characteristics of CD8+ T cell subsets in Chinese patients with chronic HIV infection during initial ART

    Directory of Open Access Journals (Sweden)

    Zhang Hongwei

    2011-03-01

    Full Text Available Abstract Background CD8+ T cells may play an important role in protecting against HIV. However, the changes of CD8+ T cell subsets during early period of ART have not been fully studied. Methods Twenty-one asymptomatic treatment-naive HIV-infected patients with CD4 T+ cells less than 350 cells/μl were enrolled in the study. Naïve, central memory(CM, effective memory(EM and terminally differentiated effector (EMRA CD8+ cell subsets and their activation and proliferation subsets were evaluated in blood samples collected at base line, and week 2, 4, 8 and 12 of ART. Results The total CD8+ T cells declined and the Naïve and CM subsets had a tendency of increase. Activation levels of all CD8+ T cell subsets except EMRA subset decreased after ART. However, proliferation levels of total CD8+ T cells, EMRA, EM and CM subsets increased at the first 4 weeks of ART, then decreased. Proliferation level of the naïve cells decreased after ART. Conclusion The changes of CD8+ T cell subsets during initial ART are complex. Our results display a complete phenotypical picture of CD8+ cell subsets during initial ART and provide insights for understanding of immune status during ART.

  8. Comprehensive Ocean - Atmosphere Data Set (COADS) LMRF Arctic Subset

    Data.gov (United States)

    National Aeronautics and Space Administration — The Comprehensive Ocean - Atmosphere Data Set (COADS) LMRF Arctic subset contains marine surface weather reports for the region north of 65 degrees N from ships,...

  9. Oxygen sensitive polymeric nanocapsules for optical dissolved oxygen sensors

    Science.gov (United States)

    Sun, Zhijuan; Cai, Chenxin; Guo, Fei; Ye, Changhuai; Luo, Yingwu; Ye, Shuming; Luo, Jianchao; Zhu, Fan; Jiang, Chunyue

    2018-04-01

    Immobilization of the oxygen-sensitive probes (OSPs) in the host matrix greatly impacts the performance and long-term usage of the optical dissolved oxygen (DO) sensors. In this work, fluorescent dyes, as the OSPs, were encapsulated with a crosslinked fluorinated polymer shell by interfacial confined reversible addition fragmentation chain transfer miniemulsion polymerization to fabricate oxygen sensitive polymeric nanocapsules (NCs). The location of fluorescent dyes and the fluorescent properties of the NCs were fully characterized by fourier transform infrared spectrometer, x-ray photoelectron spectrometer and fluorescent spectrum. Dye-encapsulated capacity can be precisely tuned from 0 to 1.3 wt% without self-quenching of the fluorescent dye. The crosslinked fluorinated polymer shell is not only extremely high gas permeability, but also prevents the fluorescent dyes from leakage in aqueous as well as in various organic solvents, such as ethanol, acetone and tetrahydrofuran (THF). An optical DO sensor based on the oxygen sensitive NCs was fabricated, showing high sensitivity, short response time, full reversibility, and long-term operational stability of online monitoring DO. The sensitivity of the optical DO sensor is 7.02 (the ratio of the response value in fully deoxygenated and saturated oxygenated water) in the range 0.96-14.16 mg l-1 and the response time is about 14.3 s. The sensor’s work curve was fit well using the modified Stern-Volmer equation by two-site model, and its response values are hardly affected by pH ranging from 2 to 12 and keep constant during continuous measurement for 3 months. It is believed that the oxygen sensitive polymeric NCs-based optical DO sensor could be particularly useful in long-term online DO monitoring in both aqueous and organic solvent systems.

  10. Ontogeny of surface markers on functionally distinct T cell subsets in the chicken.

    Science.gov (United States)

    Traill, K N; Böck, G; Boyd, R L; Ratheiser, K; Wick, G

    1984-01-01

    Three subsets of chicken peripheral T cells (T1, T2 and T3) have been identified in peripheral blood of adult chickens on the basis of fluorescence intensity after staining with certain xenogeneic anti-thymus cell sera (from turkeys and rabbits). They differentiate between 3-10 weeks of age in parallel with development of responsiveness to the mitogens concanavalin A (Con A), phytohemagglutinin (PHA) and pokeweed mitogen (PWM). Functional tests on the T subsets, sorted with a fluorescence-activated cell sorter, have shown that T2, 3 cells respond to Con A, PHA and PWM and are capable of eliciting a graft-vs.-host reaction (GvHR). In contrast, although T1 cells respond to Con A, they respond poorly to PHA and not at all to PWM or in GvHR. There was some indication of cooperation between T1 and T2,3 cells for the PHA response. Parallels between these chicken subsets and helper and suppressor/cytotoxic subsets in mammalian systems are discussed.

  11. Pulsed electron-beam-sustained discharge in oxygen-containing gas mixtures: electrical characteristics, spectroscopy,and singlet oxygen yield

    International Nuclear Information System (INIS)

    Vagin, Nikolai P; Ionin, Andrei A; Klimachev, Yu M; Kotkov, A A; Podmar'kov, Yu P; Seleznev, L V; Sinitsyn, D V; Frolov, M P; Yuryshev, Nikolai N; Kochetov, Igor' V; Napartovich, A P; Hager, G D

    2004-01-01

    The electrical and spectroscopic characteristics of electron-beam-sustained discharge (EBSD) in oxygen and oxygen-containing gas mixtures are studied experimentally under gas pressures up to 100 Torr in a large excitation volume (∼18 L). It is shown that the EBSD in pure oxygen and its mixtures with inert gases is unstable and is characterised by a small specific energy contribution. The addition of small amounts (∼1%-10%) of carbon monoxide or hydrogen to oxygen or its mixtures with inert gases considerably improves the stability of the discharge, while the specific energy contribution W increases by more then an order of magnitude, achieving ∼6.5 kJ L -1 atm -1 per molecular component of the gas mixture. A part of the energy supplied to the EBSD is spent to excite vibrational levels of molecular additives. This was demonstrated experimentally by the initiation of a CO laser based on the O 2 : Ar : CO = 1 : 1 : 0.1 mixture. Experimental results on spectroscopy of the excited electronic states O 2 (a 1 Δ g ) and O 2 (b 1 Σ g + ), of oxygen formed in the EBSD are presented. A technique was worked out for measuring the concentration of singlet oxygen in the O 2 (a 1 Δ g ) state in the afterglow of the pulsed EBSD by comparing with the radiation intensity of singlet oxygen of a given concentration produced in a chemical generator. Preliminary measurements of the singlet-oxygen yield in the EBSD show that its value ∼3% for W ∼ 1.0 kJ L -1 atm -1 is in agreement with the theoretical estimate. Theoretical calculations performed for W ∼ 6.5 kJ L -1 atm -1 at a fixed temperature show that the singlet-oxygen yield may be ∼20%, which is higher than the value required to achieve the lasing threshold in an oxygen-iodine laser at room temperature. (laser applications and other topics in quantum electronics)

  12. Criteria to Extract High-Quality Protein Data Bank Subsets for Structure Users.

    Science.gov (United States)

    Carugo, Oliviero; Djinović-Carugo, Kristina

    2016-01-01

    It is often necessary to build subsets of the Protein Data Bank to extract structural trends and average values. For this purpose it is mandatory that the subsets are non-redundant and of high quality. The first problem can be solved relatively easily at the sequence level or at the structural level. The second, on the contrary, needs special attention. It is not sufficient, in fact, to consider the crystallographic resolution and other feature must be taken into account: the absence of strings of residues from the electron density maps and from the files deposited in the Protein Data Bank; the B-factor values; the appropriate validation of the structural models; the quality of the electron density maps, which is not uniform; and the temperature of the diffraction experiments. More stringent criteria produce smaller subsets, which can be enlarged with more tolerant selection criteria. The incessant growth of the Protein Data Bank and especially of the number of high-resolution structures is allowing the use of more stringent selection criteria, with a consequent improvement of the quality of the subsets of the Protein Data Bank.

  13. DIRECT OXYGEN ABUNDANCES FOR LOW-LUMINOSITY LVL GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Berg, Danielle A.; Skillman, Evan D. [Institute for Astrophysics, University of Minnesota, 116 Church St. SE, Minneapolis, MN 55455 (United States); Marble, Andrew R.; Engelbracht, Charles W. [Steward Observatory, University of Arizona, 933 N Cherry Ave., Tucson, AZ 85721 (United States); Van Zee, Liese [Astronomy Department, Indiana University, 727 East 3rd Street, Bloomington, IN 47405 (United States); Lee, Janice C. [STScI, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Kennicutt, Robert C. Jr. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Calzetti, Daniela [Department of Astronomy, University of Massachusetts, 710 North Pleasant Street, Amherst, MA 01003 (United States); Dale, Daniel A. [Department of Physics and Astronomy, University of Wyoming, 1000 E. University, Laramie, WY 82071 (United States); Johnson, Benjamin D., E-mail: berg@astro.umn.edu, E-mail: skillman@astro.umn.edu, E-mail: cengelbracht@as.arizona.edu, E-mail: amarble@nso.edu, E-mail: vanzee@astro.indiana.edu, E-mail: jlee@stsci.edu, E-mail: calzetti@astro.umass.edu, E-mail: ddale@uwyo.edu, E-mail: johnson@iap.fr [Institut d' Astrophysique de Paris, UMR 7095, 98 bis Bvd Arago, 75014 Paris (France)

    2012-08-01

    We present MMT spectroscopic observations of H II regions in 42 low luminosity galaxies in the Spitzer Local Volume Legacy survey. For 31 of the 42 galaxies in our sample, we were able to measure the temperature sensitive [O III] {lambda}4363 line at a strength of 4{sigma} or greater, and thus determine oxygen abundances using the 'direct' method. Our results provide the first 'direct' estimates of oxygen abundance for 19 of these galaxies. 'Direct' oxygen abundances were compared to B-band luminosities, 4.5 {mu}m luminosities, and stellar masses in order to characterize the luminosity-metallicity and mass-metallicity relationships at low luminosity. We present and analyze a 'Combined Select' sample composed of 38 objects (drawn from a sub-set of our parent sample and the literature) with 'direct' oxygen abundances and reliable distance determinations (based on the tip of the red giant branch or Cepheid variables). Consistent with previous studies, the B band and 4.5 {mu}m luminosity-metallicity relationships for the 38 objects were found to be 12 + log(O/H) = (6.27 {+-} 0.21) + (- 0.11 {+-} 0.01)M{sub B} and 12 + log(O/H) = (6.10 {+-} 0.21) + (- 0.10 {+-} 0.01)M{sub [4.5]} with dispersions of {sigma} = 0.15 and 0.14, respectively. The slopes of the optical and near-IR L-Z relationships have been reported to be different for galaxies with luminosities greater than that of the LMC. However, the similarity of the slopes of the optical and near-IR L-Z relationships for our sample probably reflects little influence by dust extinction in the low luminosity galaxies. For this sample, we derive a mass-metallicity relationship of 12 + log(O/H) = (5.61 {+-} 0.24) + (0.29 {+-} 0.03)log (M{sub *}), which agrees with previous studies; however, the dispersion ({sigma} = 0.15) is not significantly lower than that of the L-Z relationships. Because of the low dispersions in these relationships, if an accurate distance is available

  14. A new continuous-flow process for catalytic conversion of glycerol to oxygenated fuel additive: Catalyst screening

    International Nuclear Information System (INIS)

    Nanda, Malaya R.; Yuan, Zhongshun; Qin, Wensheng; Ghaziaskar, Hassan S.; Poirier, Marc-Andre; Xu, Chunbao

    2014-01-01

    Highlights: • A continuous-flow process for catalytic synthesis of solketal from glycerol. • Six different heterogeneous acid catalysts were studied in the process. • Glycerol conversion and solketal yield of 90% and 88% respectively were achieved. • The process has the potential to be scaled-up for industrial applications. - Abstract: A new continuous-flow reactor was designed for the conversion of glycerol to solketal, an oxygenated fuel additive, through ketalization with acetone. Six heterogeneous catalysts were investigated with respect to their catalytic activity and stability in a flow reactor. The acidity of the catalysts positively influences the catalyst’s activity. Among all the solid acid catalysts tested, the maximum solketal yield from experiments at 40 °C, 600 psi and WHSV of 4 h −1 attained 73% and 88% at the acetone/glycerol molar ratio of 2.0 and 6.0, respectively, with Amberlyst Wet. Based on the solketal yield and glycerol conversion results, the activity of all catalysts tested follows the following order of sequence: Amberlyst Wet ≈ Zeolite ≈ Amberlyst Dry > Zirconium Sulfate > Montmorillonite > Polymax. An increase in acetone/glycerol molar ratio or a decrease in WHSV enhanced the glycerol conversion as expected. This process offers an attractive route for converting glycerol, the main by-product of biodiesel, to solketal – a value-added green product with potential industrial applications as a valuable fuel additive or combustion promoter for gasoline engines

  15. Solubility of Oxygen in Liquid Sodium and the Interpretation of Predictions for the Corrosion Rate of Stainless Steels in Liquid Sodium; Solubilidad del oxigeno en sodio liquido e interpretacion de predicciones de la velocidad de corrosion de los aceros inoxidables en sodio liquido

    Energy Technology Data Exchange (ETDEWEB)

    Claxton, K T

    1979-07-01

    A statistical analysis of all oxygen in sodium solubility data has been made. The results indicate a real difference. between levels of oxygen reported by UK und US workers. Analysis using sub-sets of culled data to derive a compromise solubility function are considered less than adequate. It is considered preferable and more realistic to distinguish data sub-sets by the analytical technique employed. The vacuum distillation method yields results differing amongst them selves by up to a factor of five at cold trap temperatures of relevance to fast reactor operation. The vanadium wire and electrochemical cell techniques give the lowest solubility values. (Author) 51 refs.

  16. Investigation of the singlet delta oxygen and ozone yields from the pulsed radiolysis of oxygen and oxygen-noble gas mixtures

    International Nuclear Information System (INIS)

    Zediker, M.S.

    1984-01-01

    The experiments discussed herein were performed with a flowing gas apparatus coupled to the University of Illinois TRIGA reactor. The detectors (lambda = 1.27 μ 634 nm) were calibrated with a novel NO 2 titration scheme and the absorbed dose was estimated from the ozone concentrations measured in pure oxygen. The results of these experiments revealed an O 2 (a 1 Δ) production efficiency of 0.14% for direct nuclear pumping in an argon-oxygen mixture. Extensive modeling of the oxygen and argon-oxygen mixtures were benchmarked against these and other experiments. However, good agreement over a broad absorbed dose range was only possible if the O 4 + + O 4 - neutralization reaction was assumed to be nondissociative. In a second set of experiments with a nuclear sustained electrical discharge (low E/N), the O 2 (a 1 Δ) production efficiency was approx.0.40% for the electrical power densities examined. In addition, the O 2 (a 1 Δ) was observed to scale with the square root of the electrical power deposition but was independent of the oxygen concentration. A simple analytic model was developed which explains this behavior as a characteristic of an externally sustained discharge involving an electron attaching gas such as oxygen. The results of these experiments and the modeling of the chemical kinetics are discussed with an emphasis on optimizing the O 2 (a 1 Δ) and O 3 yields

  17. Improved arterial blood oxygenation following intravenous infusion of cold supersaturated dissolved oxygen solution.

    Science.gov (United States)

    Grady, Daniel J; Gentile, Michael A; Riggs, John H; Cheifetz, Ira M

    2014-01-01

    One of the primary goals of critical care medicine is to support adequate gas exchange without iatrogenic sequelae. An emerging method of delivering supplemental oxygen is intravenously rather than via the traditional inhalation route. The objective of this study was to evaluate the gas-exchange effects of infusing cold intravenous (IV) fluids containing very high partial pressures of dissolved oxygen (>760 mm Hg) in a porcine model. Juvenile swines were anesthetized and mechanically ventilated. Each animal received an infusion of cold (13 °C) Ringer's lactate solution (30 mL/kg/hour), which had been supersaturated with dissolved oxygen gas (39.7 mg/L dissolved oxygen, 992 mm Hg, 30.5 mL/L). Arterial blood gases and physiologic measurements were repeated at 15-minute intervals during a 60-minute IV infusion of the supersaturated dissolved oxygen solution. Each animal served as its own control. Five swines (12.9 ± 0.9 kg) were studied. Following the 60-minute infusion, there were significant increases in PaO2 and SaO2 (P < 0.05) and a significant decrease in PaCO2 (P < 0.05), with a corresponding normalization in arterial blood pH. Additionally, there was a significant decrease in core body temperature (P < 0.05) when compared to the baseline preinfusion state. A cold, supersaturated dissolved oxygen solution may be intravenously administered to improve arterial blood oxygenation and ventilation parameters and induce a mild therapeutic hypothermia in a porcine model.

  18. Changes in Oxygen Partial Pressure in the Vitreous Body and Arterial Blood of Rabbits Depending on Oxygen Concentration in Inspired Mixture.

    Science.gov (United States)

    Amkhanitskaya, L I; Nikolaeva, G V; Sokolova, N A

    2015-07-01

    We demonstrated that the vitreous body of one-month-old rabbits becomes a "reservoir" for storage and accumulation of oxygen after exposure to additional oxygenation of the organism (O2 concentrations in inspired gas mixture were 40, 60, 85, and 99%). The higher was O2 concentration in inspired mixture, the higher was oxygen saturation of the blood and vitreous body. O2 concentration of 40% was relatively safe for eye tissues. O2 concentration >60% induced oxygen accumulation in the vitreous body, which can be a provoking factor for the development of oxygen-induced pathologies.

  19. HEMOXCell, a New Oxygen Carrier Usable as an Additive for Mesenchymal Stem Cell Culture in Platelet Lysate-Supplemented Media.

    Science.gov (United States)

    Le Pape, Fiona; Cosnuau-Kemmat, Lucie; Richard, Gaëlle; Dubrana, Frédéric; Férec, Claude; Zal, Franck; Leize, Elisabeth; Delépine, Pascal

    2017-04-01

    Human mesenchymal stem cells (MSCs) are promising candidates for therapeutic applications such as tissue engineering. However, one of the main challenges is to improve oxygen supply to hypoxic areas to reduce oxygen gradient formation while preserving MSC differentiation potential and viability. For this purpose, a marine hemoglobin, HEMOXCell, was evaluated as an oxygen carrier for culturing human bone marrow MSCs in vitro for future three-dimensional culture applications. Impact of HEMOXCell on cell growth and viability was assessed in human platelet lysate (hPL)-supplemented media. Maintenance of MSC features, such as multipotency and expression of MSC specific markers, was further investigated by biochemical assays and flow cytometry analysis. Our experimental results highlight its oxygenator potential and indicate that an optimal concentration of 0.025 g/L HEMOXCell induces a 25%-increase of the cell growth rate, preserves MSC phenotype, and maintains MSC differentiation properties; a two-fold higher concentration induces cell detachment without altering cell viability. Our data suggest the potential interest of HEMOXCell as a natural oxygen carrier for tissue engineering applications to oxygenate hypoxic areas and to maintain cell viability, functions and "stemness." These features will be further tested within three-dimensional scaffolds. © 2017 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  20. Palladium-cobalt particles as oxygen-reduction electrocatalysts

    Science.gov (United States)

    Adzic, Radoslav [East Setauket, NY; Huang, Tao [Manorville, NY

    2009-12-15

    The present invention relates to palladium-cobalt particles useful as oxygen-reducing electrocatalysts. The invention also relates to oxygen-reducing cathodes and fuel cells containing these palladium-cobalt particles. The invention additionally relates to methods for the production of electrical energy by using the palladium-cobalt particles of the invention.

  1. Studies on the stimulating effect of low dose irradiation on lymphocyte subsets

    International Nuclear Information System (INIS)

    Du Zeji; Su Liaoyuan

    1994-01-01

    In the study, three kinds of monoclonal antibody were used to separate subsets of lymphocyte, and then the functional changes of the separated subsets after low dose irradiation (LDI) were studied. McAb CD4, CD8 and B were used to obtain CD 4 + , CD8 + and B cells respectively with 'Panning' method, the cells were irradiated with X-ray machine (200 kV, 10 mA) for 0, 0.02, 0.05, 0.1, 0.2, 0.5 Gy. 3 H-TdR incorporation was used to reflect functional changes of subsets after LDI. The results indicated that (1) three kinds of subsets could be stimulated by LDI (within 0.2 Gy). The peak effect for CD 4 + and B cells was induced by 0.1 Gy irradiation for CD8 + cell, the peak effect dose was 0.05 Gy; (2) between 0.02 Gy and 0.2 Gy, for same dose, the stimulating effect of CD4 + was higher than that of CD8 + . This result has an important significance in demonstrating the immune mechanism of radiation hormesis. The past viewpoint suggested that immune hormesis was caused by the damage of radiosensitive T cell (Ts) after LDI. Recently, some authors proved that no change of the ratio of Ts to T H existed after LDI. In the study presented, It is found that the values of 3 H-TdR incorporation in CD4 + was bigger than that in CD8 + after LDI. Obvious stimulating effect could still be observed after 0.2 Gy irradiation, it indicated that subsets separated by McAb could have a wide stimulating dose range for LDI

  2. Near-infrared spectroscopy during stagnant ischemia estimates central venous oxygen saturation and mixed venous oxygen saturation discrepancy in patients with severe left heart failure and additional sepsis/septic shock

    OpenAIRE

    Mo?ina, Hugo; Podbregar, Matej

    2010-01-01

    Introduction Discrepancies of 5-24% between superior vena cava oxygen saturation (ScvO2) and mixed venous oxygen saturation (SvO2) have been reported in patients with severe heart failure. Thenar muscle tissue oxygenation (StO2) measured with near-infrared spectroscopy (NIRS) during arterial occlusion testing decreases slower in sepsis/septic shock patients (lower StO2 deoxygenation rate). The StO2 deoxygenation rate is influenced by dobutamine. The aim of this study was to determine the rela...

  3. Optimum unambiguous discrimination between subsets of nonorthogonal quantum states

    International Nuclear Information System (INIS)

    Sun Yuqing; Hillery, Mark; Bergou, Janos A.

    2002-01-01

    It is known that unambiguous discrimination among nonorthogonal but linearly independent quantum states is possible with a certain probability of success. Here, we consider a variant of that problem. Instead of discriminating among all of the different states, we shall only discriminate between two subsets of them. In particular, for the case of three nonorthogonal states, { vertical bar ψ 1 >, vertical bar ψ 2 >, vertical bar ψ 3 >}, we show that the optimal strategy to distinguish vertical bar ψ 1 > from the set { vertical bar ψ 2 >, vertical bar ψ 3 >} has a higher success rate than if we wish to discriminate among all three states. Somewhat surprisingly, for unambiguous discrimination the subsets need not be linearly independent. A fully analytical solution is presented, and we also show how to construct generalized interferometers (multiport) which provide an optical implementation of the optimal strategy

  4. Oxidation of ruthenium thin films using atomic oxygen

    Energy Technology Data Exchange (ETDEWEB)

    McCoy, A.P.; Bogan, J.; Brady, A.; Hughes, G.

    2015-12-31

    In this study, the use of atomic oxygen to oxidise ruthenium thin films is assessed. Atomic layer deposited (ALD) ruthenium thin films (~ 3 nm) were exposed to varying amounts of atomic oxygen and the results were compared to the impact of exposures to molecular oxygen. X-ray photoelectron spectroscopy studies reveal substantial oxidation of metallic ruthenium films to RuO{sub 2} at exposures as low as ~ 10{sup 2} L at 575 K when atomic oxygen was used. Higher exposures of molecular oxygen resulted in no metal oxidation highlighting the benefits of using atomic oxygen to form RuO{sub 2}. Additionally, the partial oxidation of these ruthenium films occurred at temperatures as low as 293 K (room temperature) in an atomic oxygen environment. - Highlights: • X-ray photoelectron spectroscopy study of the oxidation of Ru thin films • Oxidation of Ru thin films using atomic oxygen • Comparison between atomic oxygen and molecular oxygen treatments on Ru thin films • Fully oxidised RuO{sub 2} thin films formed with low exposures to atomic oxygen.

  5. Selective mRNA translation coordinates energetic and metabolic adjustments to cellular oxygen deprivation and reoxygenation in Arabidopsis thaliana.

    Science.gov (United States)

    Branco-Price, Cristina; Kaiser, Kayla A; Jang, Charles J H; Larive, Cynthia K; Bailey-Serres, Julia

    2008-12-01

    Cellular oxygen deprivation (hypoxia/anoxia) requires an acclimation response that enables survival during an energy crisis. To gain new insights into the processes that facilitate the endurance of transient oxygen deprivation, the dynamics of the mRNA translation state and metabolites were quantitatively monitored in Arabidopsis thaliana seedlings exposed to a short (2 h) or prolonged (9 h) period of oxygen and carbon dioxide deprivation and following 1 h of re-aeration. Hypoxia stress and reoxygenation promoted adjustments in the levels of polyribosomes (polysomes) that were highly coordinated with cellular ATP content. A quantitative comparison of steady-state and polysomal mRNA populations revealed that over half of the cellular mRNAs were restricted from polysome complexes during the stress, with little or no change in abundance. This selective repression of translation was rapidly reversed upon reoxygenation. Comparison of the adjustment in gene transcripts and metabolites demonstrated that profiling of polysomal mRNAs strongly augments the prediction of cellular processes that are altered during cellular oxygen deprivation. The selective translation of a subset of mRNAs promotes the conservation of ATP and facilitates the transition to anaerobic metabolism during low-oxygen stress.

  6. Changes in T-cell subsets after radiation therapy

    International Nuclear Information System (INIS)

    Yang, S.J.; Rafla, S.; Youssef, E.; Selim, H.; Salloum, N.; Chuang, J.Y.

    1988-01-01

    The T-cell subsets of 129 patients with cancer were counted before and after radiation therapy. The cells were labeled with monoclonal antibodies that were specific for each type of T cell. Significant changes after therapy were decreases in the proportion of T-helper/inducer cells, pan-T cells, and in the ratio of T-helper/inducer to T-suppressor/cytotoxic cells. There was an increase in the percentage of T-suppressor/cytotoxic cells. When the site of the primary cancer was considered, genitourinary cancer and cancer of the head and neck both showed a decreased percentage of T-helper/inducer cells and a reduced ratio of T-helper/inducer to T-suppressor/cytotoxic cells. The percentage of pan-T cells in head and neck cancer and the ratio of T-helper/inducer to T-suppressor/cytotoxic cells in breast cancer were decreased. The percentage of T-helper cells was particularly decreased by radiation therapy in advanced stages of cancer, in higher grade tumors, and in larger tumors. The absolute numbers of various T-cell subsets were decreased in all groups

  7. Mast cell subsets and neuropeptides in leprosy reactions

    Directory of Open Access Journals (Sweden)

    Antunes Sérgio Luiz Gomes

    2003-01-01

    Full Text Available The immunohistochemical identification of neuropeptides (calcitonin gene-related peptide, vasoactive intestinal polypeptide, substance P, alpha-melanocyte stimulating hormone and gamma-melanocyte stimulating hormone quantification of mast cells and their subsets (tryptase/chymase-immunoreactive mast cells = TCMC and tryptase-immunoreactive mast cells = TMC were determined in biopsies of six patients with leprosy reactions (three patients with type I reaction and three with type II. Biopsies were compared with those taken from the same body site in the remission stage of the same patient. We found a relative increase of TMC in the inflammatory infiltrate of the reactional biopsies compared to the post-reactional biopsy. Also, the total number of mast cells and the TMC/TCMC ratio in the inflammatory infiltrate was significantly higher than in the intervening dermis of the biopsies of both periods. No significant difference was found regarding neuroptide expression in the reactional and post-reactional biopsies. The relative increase of TMC in the reactional infiltrates could implicate this mast cell subset in the reported increase of the immune response in leprosy reactions.

  8. About Error in Measuring Oxygen Concentration by Solid-Electrolyte Sensors

    Directory of Open Access Journals (Sweden)

    V. I. Nazarov

    2008-01-01

    Full Text Available The paper evaluates additional errors while measuring oxygen concentration in a gas mixture by a solid-electrolyte cell. Experimental dependences of additional errors caused by changes in temperature in a sensor zone, discharge of gas mixture supplied to a sensor zone, partial pressure in the gas mixture and fluctuations in oxygen concentrations in the air.

  9. 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

  10. The detection of influential subsets in linear regression using an influence matrix

    OpenAIRE

    Peña, Daniel; Yohai, Víctor J.

    1991-01-01

    This paper presents a new method to identify influential subsets in linear regression problems. The procedure uses the eigenstructure of an influence matrix which is defined as the matrix of uncentered covariance of the effect on the whole data set of deleting each observation, normalized to include the univariate Cook's statistics in the diagonal. It is shown that points in an influential subset will appear with large weight in at least one of the eigenvector linked to the largest eigenvalue...

  11. Microsensor and transcriptomic signatures of oxygen depletion in biofilms associated with chronic wounds: Biofilms and oxygen

    Energy Technology Data Exchange (ETDEWEB)

    James, Garth A. [Center for Biofilm Engineering, Montana State University, Bozeman Montana; Ge Zhao, Alice [Division of Dermatology, Department of Medicine, University of Washington, Seattle Washington; Usui, Marcia [Division of Dermatology, Department of Medicine, University of Washington, Seattle Washington; Underwood, Robert A. [Division of Dermatology, Department of Medicine, University of Washington, Seattle Washington; Nguyen, Hung [The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman Washington; Beyenal, Haluk [The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman Washington; deLancey Pulcini, Elinor [Center for Biofilm Engineering, Montana State University, Bozeman Montana; Agostinho Hunt, Alessandra [Department of Microbiology and Molecular Genetics, 5180 Biomedical and Physical Sciences, Michigan State University, East Lansing Michigan; Bernstein, Hans C. [Pacific Northwest National Laboratory, Chemical and Biological Signature Science, Richland Washington; Fleckman, Philip [Division of Dermatology, Department of Medicine, University of Washington, Seattle Washington; Olerud, John [Division of Dermatology, Department of Medicine, University of Washington, Seattle Washington; Williamson, Kerry S. [Center for Biofilm Engineering, Montana State University, Bozeman Montana; Franklin, Michael J. [Center for Biofilm Engineering, Montana State University, Bozeman Montana; Stewart, Philip S. [Center for Biofilm Engineering, Montana State University, Bozeman Montana

    2016-02-16

    Polymicrobial biofilms have been implicated in delayed wound healing, although the mechanisms by which biofilms impair wound healing are poorly understood. Many species of bacteria produce exotoxins and exoenzymes that may inhibit healing. In addition, oxygen consumption by biofilms may impede wound healing. In this study, we used oxygen microsensors to measure oxygen transects through in vitro-cultured biofilms, biofilms formed in vivo in a diabetic (db/db) mouse model, and ex vivo human chronic wound specimens. The results show that oxygen levels within both euthanized and live mouse wounds had steep gradients that reached minima ranging from 19 to 61% oxygen partial pressure, compared to atmospheric oxygen levels. The oxygen gradients in the mouse wounds were similar to those observed for clinical isolates cultured in vitro and for human ex vivo scabs. No oxygen gradients were observed for heat-killed scabs, suggesting that active metabolism by the viable bacteria contributed to the reduced oxygen partial pressure of the wounds. To characterize the metabolic activities of the bacteria in the mouse wounds, we performed transcriptomics analyses of Pseudomonas aeruginosa biofilms associated with the db/db mice wounds using Affymetrix microarrays. The results demonstrated that the bacteria expressed genes for metabolic activities associated with cell growth. Interestingly, the transcriptome results indicated that the bacteria within the wounds also experienced oxygen-limitation stress. Among the bacterial genes that were expressed in vivo were genes associated with the Anr-mediated hypoxia-stress response. Other bacterial stress response genes highly expressed in vivo were genes associated with stationary-phase growth, osmotic stress, and RpoH-mediated heat shock stress. Overall, the results support the hypothesis that the metabolic activities of bacteria in biofilms act as oxygen sinks in chronic wounds and that the depletion of oxygen contributes to the

  12. The CD44(high tumorigenic subsets in lung cancer biospecimens are enriched for low miR-34a expression.

    Directory of Open Access Journals (Sweden)

    Saroj K Basak

    Full Text Available Cellular heterogeneity is an integral part of cancer development and progression. Progression can be associated with emergence of cells that exhibit high phenotypic plasticity (including "de-differentiation" to primitive developmental states, and aggressive behavioral properties (including high tumorigenic potentials. We observed that many biomarkers that are used to identify Cancer Stem Cells (CSC can label cell subsets in an advanced clinical stage of lung cancer (malignant pleural effusions, or MPE. Thus, CSC-biomarkers may be useful for live sorting functionally distinct cell subsets from individual tumors, which may enable investigators to hone in on the molecular basis for functional heterogeneity. We demonstrate that the CD44(hi (CD44-high cancer cell subsets display higher clonal, colony forming potential than CD44(lo cells (n=3 and are also tumorigenic (n=2/2 when transplanted in mouse xenograft model. The CD44(hi subsets express different levels of embryonal (de-differentiation markers or chromatin regulators. In archived lung cancer tissues, ALDH markers co-localize more with CD44 in squamous cell carcinoma (n=5/7 than Adeno Carcinoma (n=1/12. MPE cancer cells and a lung cancer cell line (NCI-H-2122 exhibit chromosomal abnormalities and 1p36 deletion (n=3/3. Since miR-34a maps to the 1p36 deletion site, low miR-34a expression levels were detected in these cells. The colony forming efficiency of CD44(hi cells, characteristic property of CSC, can be inhibited by mir-34a replacement in these samples. In addition the highly tumorigenic CD44(hi cells are enriched for cells in the G2 phase of cell cycle.

  13. Joseph Priestley, oxygen, and the enlightenment.

    Science.gov (United States)

    West, John B

    2014-01-01

    Joseph Priestley (1733–1804) was the first person to report the discovery of oxygen and describe some of its extraordinary properties. As such he merits a special place in the history of respiratory physiology. In addition his descriptions in elegant 18th-century English were particularly arresting, and rereading them never fails to give a special pleasure. The gas was actually first prepared by Scheele (1742–1786) but his report was delayed. Lavoisier (1743–1794) repeated Priestley's initial experiment and went on to describe the true nature of oxygen that had eluded Priestley, who never abandoned the erroneous phlogiston theory. In addition to oxygen, Priestley isolated and characterized seven other gases. However, most of his writings were in theology because he was a conscientious clergyman all his life. Priestley was a product of the Enlightenment and argued that all beliefs should be able to stand the scientific scrutiny of experimental investigations. As a result his extreme liberal views were severely criticized by the established Church of England. In addition he was a supporter of both the French and American Revolutions. Ultimately his political and religious attitudes provoked a riot during which his home and his scientific equipment were destroyed. He therefore emigrated to America in 1794 where his friends included Thomas Jefferson and Benjamin Franklin. He settled in Northumberland, Pennsylvania although his scientific work never recovered from his forced departure. But the descriptions of his experiments with oxygen will always remain a high point in the history of respiratory physiology.

  14. Regulation of EMMPRIN (CD147) on monocyte subsets in patients with symptomatic coronary artery disease.

    Science.gov (United States)

    Sturhan, Henrik; Ungern-Sternberg, Saskia N I v; Langer, Harald; Gawaz, Meinrad; Geisler, Tobias; May, Andreas E; Seizer, Peter

    2015-06-01

    The role of individual monocyte subsets in inflammatory cardiovascular diseases is insufficiently understood. Although the Extracellular Matrix Metalloproteinase Inducer (EMMPRIN) regulates important processes for inflammation such as MMP-release, its expression and regulation on monocyte subsets has not been characterized. In this clinical study, blood was obtained from 80 patients with stable coronary artery disease (CAD), 49 with acute myocardial infarction (AMI) and 34 healthy controls. Monocytes were divided into 3 subsets: CD14(++)CD16(-) (low), CD14(++)CD16(+) (intermediate), CD14(+)CD16(++) (high) according to phenotypic markers analyzed by flow cytometry. Surface expression of EMMPRIN was evaluated and compared with CD36 and CD47 expression. In all patients, EMMPRIN expression was significantly different among monocyte subsets with the highest expression on "classical" CD14(++)CD16(-) monocytes. EMMPRIN was upregulated on all monocyte subsets in patients with AMI as compared to patients with stable CAD. Notably, neither CD47 nor CD36 revealed a significant difference in patients with AMI compared to patients with stable CAD. EMMPRIN could serve as a marker for classical monocytes, which is upregulated in patients with acute myocardial infarction. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Design of a lunar oxygen production plant

    Science.gov (United States)

    Radhakrishnan, Ramalingam

    1990-01-01

    To achieve permanent human presence and activity on the moon, oxygen is required for both life support and propulsion. Lunar oxygen production using resources existing on the moon will reduce or eliminate the need to transport liquid oxygen from earth. In addition, the co-products of oxygen production will provide metals, structural ceramics, and other volatile compounds. This will enable development of even greater self-sufficiency as the lunar outpost evolves. Ilmenite is the most abundant metal-oxide mineral in the lunar regolith. A process involving the reaction of ilmenite with hydrogen at 1000 C to produce water, followed by the electrolysis of this water to provide oxygen and recycle the hydrogen has been explored. The objective of this 1990 Summer Faculty Project was to design a lunar oxygen-production plant to provide 5 metric tons of liquid oxygen per year from lunar soil. The results of this study describe the size and mass of the equipment, the power needs, feedstock quantity and the engineering details of the plant.

  16. B-cell subset alterations and correlated factors in HIV-1 infection.

    Science.gov (United States)

    Pensieroso, Simone; Galli, Laura; Nozza, Silvia; Ruffin, Nicolas; Castagna, Antonella; Tambussi, Giuseppe; Hejdeman, Bo; Misciagna, Donatella; Riva, Agostino; Malnati, Mauro; Chiodi, Francesca; Scarlatti, Gabriella

    2013-05-15

    During HIV-1 infection, the development, phenotype, and functionality of B cells are impaired. Transitional B cells and aberrant B-cell populations arise in blood, whereas a declined percentage of resting memory B cells is detected. Our study aimed at pinpointing the demographic, immunological, and viral factors driving these pathological findings, and the role of antiretroviral therapy in reverting these alterations. B-cell phenotype and correlating factors were evaluated. Variations in B-cell subsets were evaluated by flow cytometry in HIV-1-infected individuals naive to therapy, elite controllers, and patients treated with antiretroviral drugs (virological control or failure). Multivariable analysis was performed to identify variables independently associated with the B-cell alterations. Significant differences were observed among patients' groups in relation to all B-cell subsets. Resting memory B cells were preserved in patients naive to therapy and elite controllers, but reduced in treated patients. Individuals naive to therapy and experiencing multidrug failure, as well as elite controllers, had significantly higher levels of activated memory B cells compared to healthy controls. In the multivariate analysis, plasma viral load and nadir CD4 T cells independently correlated with major B-cell alterations. Coinfection with hepatitis C but not hepatitis B virus also showed an impact on specific B-cell subsets. Successful protracted antiretroviral treatment led to normalization of all B-cell subsets with exception of resting memory B cells. Our results indicate that viremia and nadir CD4 T cells are important prognostic markers of B-cell perturbations and provide evidence that resting memory B-cell depletion during chronic infection is not reverted upon successful antiretroviral therapy.

  17. A Hybrid Soft Computing Approach for Subset Problems

    Directory of Open Access Journals (Sweden)

    Broderick Crawford

    2013-01-01

    Full Text Available Subset problems (set partitioning, packing, and covering are formal models for many practical optimization problems. A set partitioning problem determines how the items in one set (S can be partitioned into smaller subsets. All items in S must be contained in one and only one partition. Related problems are set packing (all items must be contained in zero or one partitions and set covering (all items must be contained in at least one partition. Here, we present a hybrid solver based on ant colony optimization (ACO combined with arc consistency for solving this kind of problems. ACO is a swarm intelligence metaheuristic inspired on ants behavior when they search for food. It allows to solve complex combinatorial problems for which traditional mathematical techniques may fail. By other side, in constraint programming, the solving process of Constraint Satisfaction Problems can dramatically reduce the search space by means of arc consistency enforcing constraint consistencies either prior to or during search. Our hybrid approach was tested with set covering and set partitioning dataset benchmarks. It was observed that the performance of ACO had been improved embedding this filtering technique in its constructive phase.

  18. Mouse NK cell-mediated rejection of bone marrow allografts exhibits patterns consistent with Ly49 subset licensing.

    Science.gov (United States)

    Sun, Kai; Alvarez, Maite; Ames, Erik; Barao, Isabel; Chen, Mingyi; Longo, Dan L; Redelman, Doug; Murphy, William J

    2012-02-09

    Natural killer (NK) cells can mediate the rejection of bone marrow allografts and exist as subsets based on expression of inhibitory/activating receptors that can bind MHC. In vitro data have shown that NK subsets bearing Ly49 receptors for self-MHC class I have intrinsically higher effector function, supporting the hypothesis that NK cells undergo a host MHC-dependent functional education. These subsets also play a role in bone marrow cell (BMC) allograft rejection. Thus far, little in vivo evidence for this preferential licensing across mouse strains with different MHC haplotypes has been shown. We assessed the intrinsic response potential of the different Ly49(+) subsets in BMC rejection by using β2-microglobulin deficient (β2m(-/-)) mice as donors. Using congenic and allogeneic mice as recipients and depleting the different Ly49 subsets, we found that NK subsets bearing Ly49s, which bind "self-MHC" were found to be the dominant subset responsible for β2m(-/-) BMC rejection. This provides in vivo evidence for host MHC class I-dependent functional education. Interestingly, all H2(d) strain mice regardless of background were able to resist significantly greater amounts of β2m(-/-), but not wild-type BMC than H2(b) mice, providing evidence that the rheostat hypothesis regarding Ly49 affinities for MHC and NK-cell function impacts BMC rejection capability.

  19. Subset selection for an epsilon-best population : efficiency results

    NARCIS (Netherlands)

    Laan, van der P.

    1991-01-01

    An almost best or an \\epsilon-best population is defined as a population with location parameter on a distance not larger than \\epsilon (\\geq 0) from the best population (with largest value of the location parameter). For the subset selection tables with the relative efficiency of selecting an

  20. T-lymphocyte subsets, thymic size and breastfeeding in infancy

    DEFF Research Database (Denmark)

    Jeppesen, Dorthe Lisbeth; Hasselbalch, Helle; Lisse, Ida M

    2004-01-01

    We followed the changes in concentration of T-lymphocyte subsets (CD4+ and CD8+ cells) in peripheral blood and thymus size during infancy. Previous studies have found increased thymus size in breastfed infants. The present study analyzed the association between breastfeeding and the number of CD4...

  1. 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...

  2. The expanding universe of T-cell subsets: Th1, Th2 and more.

    Science.gov (United States)

    Mosmann, T R; Sad, S

    1996-03-01

    Since their discovery nearly ten years ago, T helper 1 (Th1) and Th2 subsets have been implicated in the regulation of many immune responses. In this article, Tim Mosmann and Subash Sad discuss the increasing number of T-cell subsets defined by cytokine patterns; the differentiation pathways of CD4+ and CD8+ T cells; the contribution of other cell types to these patterns; and the cytokine interactions during infection and pregnancy.

  3. Impaired Subset Progression and Polyfunctionality of T Cells in Mice Exposed to Methamphetamine during Chronic LCMV Infection.

    Science.gov (United States)

    Sriram, Uma; Hill, Beth L; Cenna, Jonathan M; Gofman, Larisa; Fernandes, Nicole C; Haldar, Bijayesh; Potula, Raghava

    2016-01-01

    Methamphetamine (METH) is a widely used psychostimulant that severely impacts the host's innate and adaptive immune systems and has profound immunological implications. T cells play a critical role in orchestrating immune responses. We have shown recently how chronic exposure to METH affects T cell activation using a murine model of lymphocytic choriomeningitis virus (LCMV) infection. Using the TriCOM (trinary state combinations) feature of GemStone™ to study the polyfunctionality of T cells, we have analyzed how METH affected the cytokine production pattern over the course of chronic LCMV infection. Furthermore, we have studied in detail the effects of METH on splenic T cell functions, such as cytokine production and degranulation, and how they regulate each other. We used the Probability State Modeling (PSM) program to visualize the differentiation of effector/memory T cell subsets during LCMV infection and analyze the effects of METH on T cell subset progression. We recently demonstrated that METH increased PD-1 expression on T cells during viral infection. In this study, we further analyzed the impact of PD-1 expression on T cell functional markers as well as its expression in the effector/memory subsets. Overall, our study indicates that analyzing polyfunctionality of T cells can provide additional insight into T cell effector functions. Analysis of T cell heterogeneity is important to highlight changes in the evolution of memory/effector functions during chronic viral infections. Our study also highlights the impact of METH on PD-1 expression and its consequences on T cell responses.

  4. Bayesian Subset Modeling for High-Dimensional Generalized Linear Models

    KAUST Repository

    Liang, Faming

    2013-06-01

    This article presents a new prior setting for high-dimensional generalized linear models, which leads to a Bayesian subset regression (BSR) with the maximum a posteriori model approximately equivalent to the minimum extended Bayesian information criterion model. The consistency of the resulting posterior is established under mild conditions. Further, a variable screening procedure is proposed based on the marginal inclusion probability, which shares the same properties of sure screening and consistency with the existing sure independence screening (SIS) and iterative sure independence screening (ISIS) procedures. However, since the proposed procedure makes use of joint information from all predictors, it generally outperforms SIS and ISIS in real applications. This article also makes extensive comparisons of BSR with the popular penalized likelihood methods, including Lasso, elastic net, SIS, and ISIS. The numerical results indicate that BSR can generally outperform the penalized likelihood methods. The models selected by BSR tend to be sparser and, more importantly, of higher prediction ability. In addition, the performance of the penalized likelihood methods tends to deteriorate as the number of predictors increases, while this is not significant for BSR. Supplementary materials for this article are available online. © 2013 American Statistical Association.

  5. Generation of a novel regulatory NK cell subset from peripheral blood CD34+ progenitors promoted by membrane-bound IL-15.

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    Massimo Giuliani

    Full Text Available BACKGROUND: NK cells have been long time considered as cytotoxic lymphocytes competent in killing virus-infected cells and tumors. However, NK cells may also play essential immuno-regulatory functions. In this context, the real existence of a defined NK subset with negative regulatory properties has been hypothesized but never clearly demonstrated. METHODOLOGY/PRINCIPAL FINDINGS: Herein, we show the in vitro generation from human peripheral blood haematopoietic progenitors (PB-HP, of a novel subset of non-cytolytic NK cells displaying a mature phenotype and remarkable immuno-regulatory functions (NK-ireg. The main functional hallmark of these NK-ireg cells is represented by the surface expression/release of HLA-G, a major immunosuppressive molecule. In addition, NK-ireg cells secrete two powerful immuno-regulatory factors: IL-10 and IL-21. Through these factors, NK-ireg cells act as effectors of the down-regulation of the immune response: reconverting mature myeloid DC (mDC into immature/tolerogenic DC, blocking cytolytic functions on conventional NK cells and inducing HLA-G membrane expression on PB-derived monocytes. The generation of "NK-ireg" cells is obtained, by default, in culture conditions favouring cell-to-cell contacts, and it is strictly dependent on reciprocal trans-presentation of membrane-bound IL-15 forms constitutively and selectively expressed by human CD34(+ PB-HP. Finally, a small subset of NKp46(+ HLA-G(+ IL-10(+ is detected within freshly isolated decidual NK cells, suggesting that these cells could represent an in vivo counterpart of the NK-ireg cells. CONCLUSIONS/SIGNIFICANCE: In conclusion, NK-ireg cells represent a novel truly differentiated non-cytolytic NK subset with a self-sustainable phenotype (CD56(+ CD16(+ NKp30(+ NKp44(+ NKp46(+ CD94(+ CD69(+ CCR7(+ generated from specific pSTAT6(+ GATA3(+ precursors. NK-ireg cells could be employed to develop new immuno-suppressive strategies in autoimmune diseases, transplant

  6. Chemokine-mediated distribution of dendritic cell subsets in renal cell carcinoma

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    Meyer Werner

    2010-10-01

    Full Text Available Abstract Background Renal cell carcinoma (RCC represents one of the most immunoresponsive cancers. Antigen-specific vaccination with dendritic cells (DCs in patients with metastatic RCC has been shown to induce cytotoxic T-cell responses associated with objective clinical responses. Thus, clinical trials utilizing DCs for immunotherapy of advanced RCCs appear to be promising; however, detailed analyses concerning the distribution and function of DC subsets in RCCs are lacking. Methods We characterized the distribution of the different immature and mature myeloid DC subsets in RCC tumour tissue and the corresponding normal kidney tissues. In further analyses, the expression of various chemokines and chemokine receptors controlling the migration of DC subsets was investigated. Results The highest numbers of immature CD1a+ DCs were found within RCC tumour tissue. In contrast, the accumulation of mature CD83+/DC-LAMP+ DCs were restricted to the invasive margin of the RCCs. The mature DCs formed clusters with proliferating T-cells. Furthermore, a close association was observed between MIP-3α-producing tumour cells and immature CCR6+ DC recruitment to the tumour bed. Conversely, MIP-3β and SLC expression was only detected at the tumour border, where CCR7-expressing T-cells and mature DCs formed clusters. Conclusion Increased numbers of immature DCs were observed within the tumour tissue of RCCs, whereas mature DCs were found in increased numbers at the tumour margin. Our results strongly implicate that the distribution of DC subsets is controlled by local lymphoid chemokine expression. Thus, increased expression of MIP-3α favours recruitment of immature DCs to the tumour bed, whereas de novo local expression of SLC and MIP-3β induces accumulation of mature DCs at the tumour margin forming clusters with proliferating T-cells reflecting a local anti-tumour immune response.

  7. Chemokine-mediated distribution of dendritic cell subsets in renal cell carcinoma

    International Nuclear Information System (INIS)

    Middel, Peter; Brauneck, Sven; Meyer, Werner; Radzun, Heinz-Joachim

    2010-01-01

    Renal cell carcinoma (RCC) represents one of the most immunoresponsive cancers. Antigen-specific vaccination with dendritic cells (DCs) in patients with metastatic RCC has been shown to induce cytotoxic T-cell responses associated with objective clinical responses. Thus, clinical trials utilizing DCs for immunotherapy of advanced RCCs appear to be promising; however, detailed analyses concerning the distribution and function of DC subsets in RCCs are lacking. We characterized the distribution of the different immature and mature myeloid DC subsets in RCC tumour tissue and the corresponding normal kidney tissues. In further analyses, the expression of various chemokines and chemokine receptors controlling the migration of DC subsets was investigated. The highest numbers of immature CD1a+ DCs were found within RCC tumour tissue. In contrast, the accumulation of mature CD83+/DC-LAMP+ DCs were restricted to the invasive margin of the RCCs. The mature DCs formed clusters with proliferating T-cells. Furthermore, a close association was observed between MIP-3α-producing tumour cells and immature CCR6+ DC recruitment to the tumour bed. Conversely, MIP-3β and SLC expression was only detected at the tumour border, where CCR7-expressing T-cells and mature DCs formed clusters. Increased numbers of immature DCs were observed within the tumour tissue of RCCs, whereas mature DCs were found in increased numbers at the tumour margin. Our results strongly implicate that the distribution of DC subsets is controlled by local lymphoid chemokine expression. Thus, increased expression of MIP-3α favours recruitment of immature DCs to the tumour bed, whereas de novo local expression of SLC and MIP-3β induces accumulation of mature DCs at the tumour margin forming clusters with proliferating T-cells reflecting a local anti-tumour immune response

  8. Subsetting Tools for Enabling Easy Access to International Airborne Chemistry Data

    Science.gov (United States)

    Northup, E. A.; Chen, G.; Quam, B. M.; Beach, A. L., III; Silverman, M. L.; Early, A. B.

    2017-12-01

    In response to the Research Opportunities in Earth and Space Science (ROSES) 2015 release announcement for Advancing Collaborative Connections for Earth System Science (ACCESS), researchers at NASA Langley Research Center (LaRC) proposed to extend the capabilities of the existing Toolsets for Airborne Data (TAD) to include subsetting functionality to allow for easier access to international airborne field campaign data. Airborne field studies are commonly used to gain a detailed understanding of atmospheric processes for scientific research on international climate change and air quality issues. To accommodate the rigorous process for manipulating airborne field study chemistry data, and to lessen barriers for researchers, TAD was created with the ability to geolocate data from various sources measured on different time scales from a single flight. The analysis of airborne chemistry data typically requires data subsetting, which can be challenging and resource-intensive for end users. In an effort to streamline this process, new data subsetting features and updates to the current database model will be added to the TAD toolset. These will include two subsetters: temporal and spatial, and vertical profile. The temporal and spatial subsetter will allow users to both focus on data from a specific location and/or time period. The vertical profile subsetter will retrieve data collected during an individual aircraft ascent or descent spiral. These new web-based tools will allow for automation of the typically labor-intensive manual data subsetting process, which will provide users with data tailored to their specific research interests. The system has been designed to allow for new in-situ airborne missions to be added as they become available, with only minor pre-processing required. The development of these enhancements will be discussed in this presentation.

  9. Differential adipokine receptor expression on circulating leukocyte subsets in lean and obese children.

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    Genoveva Keustermans

    Full Text Available Childhood obesity prevalence has increased worldwide and is an important risk factor for type 2 diabetes (T2D and cardiovascular disease (CVD. The production of inflammatory adipokines by obese adipose tissue contributes to the development of T2D and CVD. While levels of circulating adipokines such as adiponectin and leptin have been established in obese children and adults, the expression of adiponectin and leptin receptors on circulating immune cells can modulate adipokine signalling, but has not been studied so far. Here, we aim to establish the expression of adiponectin and leptin receptors on circulating immune cells in obese children pre and post-lifestyle intervention compared to normal weight control children.13 obese children before and after a 1-year lifestyle intervention were compared with an age and sex-matched normal weight control group of 15 children. Next to routine clinical and biochemical parameters, circulating adipokines were measured, and flow cytometric analysis of adiponectin receptor 1 and 2 (AdipoR1, AdipoR2 and leptin receptor expression on peripheral blood mononuclear cell subsets was performed.Obese children exhibited typical clinical and biochemical characteristics compared to controls, including a higher BMI-SD, blood pressure and circulating leptin levels, combined with a lower insulin sensitivity index (QUICKI. The 1-year lifestyle intervention resulted in stabilization of their BMI-SD. Overall, circulating leukocyte subsets showed distinct adipokine receptor expression profiles. While monocytes expressed high levels of all adipokine receptors, NK and iNKT cells predominantly expressed AdipoR2, and B-lymphocytes and CD4+ and CD8+ T-lymphocyte subsets expressed AdipoR2 as well as leptin receptor. Strikingly though, leukocyte subset numbers and adipokine receptor expression profiles were largely similar in obese children and controls. Obese children showed higher naïve B-cell numbers, and pre-intervention also

  10. 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

  11. Individual discriminative face recognition models based on subsets of features

    DEFF Research Database (Denmark)

    Clemmensen, Line Katrine Harder; Gomez, David Delgado; Ersbøll, Bjarne Kjær

    2007-01-01

    The accuracy of data classification methods depends considerably on the data representation and on the selected features. In this work, the elastic net model selection is used to identify meaningful and important features in face recognition. Modelling the characteristics which distinguish one...... person from another using only subsets of features will both decrease the computational cost and increase the generalization capacity of the face recognition algorithm. Moreover, identifying which are the features that better discriminate between persons will also provide a deeper understanding...... of the face recognition problem. The elastic net model is able to select a subset of features with low computational effort compared to other state-of-the-art feature selection methods. Furthermore, the fact that the number of features usually is larger than the number of images in the data base makes feature...

  12. Oxygen ordering in Nb(1 1 0) films

    International Nuclear Information System (INIS)

    Hellwig, O.; Zabel, H.

    2003-01-01

    Synchrotron X-ray diffraction (XRD) during the atmospheric oxidation of epitaxial Nb(1 1 0) films at elevated temperature reveals the formation of highly ordered oxygen phases within the Nb lattice. The oxygen is stored on interstitial lattice sites without destroying the basic BCC structure of the Nb host lattice. However the lattice exhibits an out-of-plane lattice expansion of up to 4.3%. During oxidation we observe the formation of a non-ordered lattice gas phase succeeded by a well-defined sequence of oxygen superstructures until finally the whole film is consumed by the formation of amorphous Nb 2 O 5 . We show that XRD is an excellent tool to monitor the exact evolution of the different oxygen phases. In addition we demonstrate that UHV post-annealing of partially oxidized films can be used to rearrange the oxygen within the sample while keeping the overall amount of oxygen constant

  13. Thermodynamics of oxygen in solid solution in vanadium and niobium--vanadium alloys

    International Nuclear Information System (INIS)

    Steckel, G.L.

    1977-01-01

    A thermodynamic study was made of the vanadium-oxygen and niobium-vanadium-oxygen systems utilizing the solid state galvanic cell technique. Investigations were made with a ThO 2 /Y 2 O 3 electrolyte over the temperature ranges 700 to 1200 0 C (973 to 1473 K) for the binary system and 650 to 1150 0 C (923 to 1423 K) for the ternary system. The activity of oxygen in vanadium obeys Henry's law for the temperatures of this investigation for concentrations up to 3.2 at. percent oxygen. For higher concentrations the activity coefficient shows positive deviations from Henry's law. The terminal solubility of oxygen in vanadium was determined. The activity of oxygen in Nb--V alloys obeys Henry's law for the temperatures of this study for oxygen concentrations less than approximately 2 at. percent. For certain Nb/V ratios Henry's law is obeyed for concentrations as high as 6.5 at. percent oxygen. First order entropy and enthalpy interaction coefficients have been determined to describe the effect on the oxygen activity of niobium additions to vanadium-rich alloys with dilute oxygen concentrations. Niobium causes relatively small decreases in the oxygen activity of V-rich alloys and increases the oxygen solubility limit. Vanadium additions to Nb-rich alloys also increases the oxygen solubility and causes substantial decreases in the dilute solution oxygen activities. The change in the thermodynamic properties when molecular oxygen dissolves in vanadium and niobium--vanadium alloys and the equilibrium oxygen pressure over the binary and ternary systems were also determined

  14. Phenotypic, ultra-structural, and functional characterization of bovine peripheral blood dendritic cell subsets.

    Directory of Open Access Journals (Sweden)

    Janet J Sei

    Full Text Available Dendritic cells (DC are multi-functional cells that bridge the gap between innate and adaptive immune systems. In bovine, significant information is lacking on the precise identity and role of peripheral blood DC subsets. In this study, we identify and characterize bovine peripheral blood DC subsets directly ex vivo, without further in vitro manipulation. Multi-color flow cytometric analysis revealed that three DC subsets could be identified. Bovine plasmacytoid DC were phenotypically identified by a unique pattern of cell surface protein expression including CD4, exhibited an extensive endoplasmic reticulum and Golgi apparatus, efficiently internalized and degraded exogenous antigen, and were the only peripheral blood cells specialized in the production of type I IFN following activation with Toll-like receptor (TLR agonists. Conventional DC were identified by expression of a different pattern of cell surface proteins including CD11c, MHC class II, and CD80, among others, the display of extensive dendritic protrusions on their plasma membrane, expression of very high levels of MHC class II and co-stimulatory molecules, efficient internalization and degradation of exogenous antigen, and ready production of detectable levels of TNF-alpha in response to TLR activation. Our investigations also revealed a third novel DC subset that may be a precursor of conventional DC that were MHC class II+ and CD11c-. These cells exhibited a smooth plasma membrane with a rounded nucleus, produced TNF-alpha in response to TLR-activation (albeit lower than CD11c+ DC, and were the least efficient in internalization/degradation of exogenous antigen. These studies define three bovine blood DC subsets with distinct phenotypic and functional characteristics which can be analyzed during immune responses to pathogens and vaccinations of cattle.

  15. Methane Post-Processing for Oxygen Loop Closure

    Science.gov (United States)

    Greenwood, Zachary W.; Abney, Morgan B.; Miller, Lee

    2016-01-01

    State-of-the-art United States Atmospheric Revitalization carbon dioxide (CO2) reduction is based on the Sabatier reaction process, which recovers approximately 50% of the oxygen (O2) from crew metabolic CO2. Oxygen recovery from carbon dioxide is constrained by the limited availability of reactant hydrogen. Post-processing of methane to recover hydrogen with the Umpqua Research Company Plasma Pyrolysis Assembly (PPA) has the potential to further close the Atmospheric Revitalization oxygen loop. The PPA decomposes methane into hydrogen and hydrocarbons, predominantly acetylene, and a small amount of solid carbon. The hydrogen must then be purified before it can be recycled for additional oxygen recovery. Long duration testing and evaluation of a four crew-member sized PPA and a discussion of hydrogen recycling system architectures are presented.

  16. Psychological stress during exercise: lymphocyte subset redistribution in firefighters.

    Science.gov (United States)

    Huang, Chun-Jung; Webb, Heather E; Garten, Ryan S; Kamimori, Gary H; Acevedo, Edmund O

    2010-10-05

    The purpose of this study examined the changes in heart rate (HR), catecholamines (NE, EPI) and percentages of blood lymphocyte subsets (CD3+ T cells, CD3+CD4+ helper T cells, CD3+CD8+ cytotoxic T cells, CD3- CD56+ NK cells, CD4/CD8 ratio, CD19+ B cells, and total lymphocytes [NK cells+T cells+B cells]) in firefighters exposed to a computerized firefighting strategies and tactics decision-making challenge while participating in moderate intensity exercise. Furthermore, this study also examined the possible relationships between catecholamines (NE and EPI) and blood lymphocyte subsets following combined mental and physical challenge. Ten professional male firefighters participated in two counterbalanced exercise conditions on a cycle ergometer: (1) 37min of cycle ergometry at 60% VO(2max) (exercise alone condition; EAC) and (2) 37min of cycle ergometry at 60% VO(2max) along with 20min of a computerized firefighting strategies and tactics decision-making challenge (firefighting strategies condition; FSC). FSC elicited significantly greater HR, NE, and EPI when compared to EAC. Both EAC and FSC elicited increases in CD3- CD56+ NK cells. The percentages of CD3+ T cells, CD3+CD4+ helper T cells, CD4/CD8 ratio, CD19+ B cells, and total lymphocytes were lower immediately following both conditions. Following dual challenge NE AUC was negatively correlated with percentage of CD19+ B cells immediately post challenge, and HR was negatively associated with the percent change in the CD4/CD8 ratio from pre to post challenge. These elevations in NE and heart rate simultaneously in response to the dual challenge suggest greater sympathetic activation that in turn would possibly explain the alteration in the distribution of lymphocyte subsets. Published by Elsevier Inc.

  17. Oxygen isotope exchange between refractory inclusion in allende and solar nebula Gas

    Science.gov (United States)

    Yurimoto; Ito; Nagasawa

    1998-12-04

    A calcium-aluminum-rich inclusion (CAI) from the Allende meteorite was analyzed and found to contain melilite crystals with extreme oxygen-isotope compositions ( approximately 5 percent oxygen-16 enrichment relative to terrestrial oxygen-16). Some of the melilite is also anomalously enriched in oxygen-16 compared with oxygen isotopes measured in other CAIs. The oxygen isotopic variation measured among the minerals (melilite, spinel, and fassaite) indicates that crystallization of the CAI started from oxygen-16-rich materials that were probably liquid droplets in the solar nebula, and oxygen isotope exchange with the surrounding oxygen-16-poor nebular gas progressed through the crystallization of the CAI. Additional oxygen isotope exchange also occurred during subsequent reheating events in the solar nebula.

  18. Hierarchical modeling for rare event detection and cell subset alignment across flow cytometry samples.

    Directory of Open Access Journals (Sweden)

    Andrew Cron

    Full Text Available Flow cytometry is the prototypical assay for multi-parameter single cell analysis, and is essential in vaccine and biomarker research for the enumeration of antigen-specific lymphocytes that are often found in extremely low frequencies (0.1% or less. Standard analysis of flow cytometry data relies on visual identification of cell subsets by experts, a process that is subjective and often difficult to reproduce. An alternative and more objective approach is the use of statistical models to identify cell subsets of interest in an automated fashion. Two specific challenges for automated analysis are to detect extremely low frequency event subsets without biasing the estimate by pre-processing enrichment, and the ability to align cell subsets across multiple data samples for comparative analysis. In this manuscript, we develop hierarchical modeling extensions to the Dirichlet Process Gaussian Mixture Model (DPGMM approach we have previously described for cell subset identification, and show that the hierarchical DPGMM (HDPGMM naturally generates an aligned data model that captures both commonalities and variations across multiple samples. HDPGMM also increases the sensitivity to extremely low frequency events by sharing information across multiple samples analyzed simultaneously. We validate the accuracy and reproducibility of HDPGMM estimates of antigen-specific T cells on clinically relevant reference peripheral blood mononuclear cell (PBMC samples with known frequencies of antigen-specific T cells. These cell samples take advantage of retrovirally TCR-transduced T cells spiked into autologous PBMC samples to give a defined number of antigen-specific T cells detectable by HLA-peptide multimer binding. We provide open source software that can take advantage of both multiple processors and GPU-acceleration to perform the numerically-demanding computations. We show that hierarchical modeling is a useful probabilistic approach that can provide a

  19. Formation and properties of metal-oxygen atomic chains

    DEFF Research Database (Denmark)

    Thijssen, W.H.A.; Strange, Mikkel; de Brugh, J.M.J.A.

    2008-01-01

    of longer atomic chains. The mechanical and electrical properties of these diatomic chains have been investigated by determining local vibration modes of the chain and by measuring the dependence of the average chain-conductance on the length of the chain. Additionally, we have performed calculations......Suspended chains consisting of single noble metal and oxygen atoms have been formed. We provide evidence that oxygen can react with and be incorporated into metallic one-dimensional atomic chains. Oxygen incorporation reinforces the linear bonds in the chain, which facilitates the creation...

  20. The regulatory roles of B cell subsets in transplantation.

    Science.gov (United States)

    Chu, Zhulang; Zou, Weilong; Xu, Yanan; Sun, Qiquan; Zhao, Yong

    2018-02-01

    B cells mediate allograft rejection through antigen presentation, and production of cytokines and antibodies. More and more immunosuppressive agents specifically targeting B cells and plasma cells have been applied in clinical transplantation. However, recent studies have indicated the regulatory roles of B cells. Therefore, it is vital to clarify the different effects of B cell subsets in organ transplantation so that we can completely understand the diverse functions of B cells in transplantation. Areas covered: This review focuses on the regulatory roles of B cells in transplantation. B cell subsets with immune modulation and factors mediating immunosuppressive functions of regulatory B (Breg) cells were analyzed. Therapies targeting B cells and the application of B cells for transplant tolerance induction were discussed. Expert commentary: Besides involving rejection, B cells could also play regulatory roles in transplantation. Breg cells and the related markers may be used to predict the immune tolerant state in transplant recipients. New therapeutic strategies targeting B cells should be explored to promote tolerance induction with less impact on the host's protective immunity in organ transplanted patients.

  1. The Role of Oxygen Therapies in Carbon Monoxide Poisoning

    Directory of Open Access Journals (Sweden)

    Suleyman Metin

    2011-08-01

    Full Text Available Due to climate and socio-economic issues in Turkey, the incidence of carbon monoxide (CO poisoning is high, especially in winter. Clinical manifestations may vary depending on the type of CO source, concentration and duration of exposure. The symptoms of CO poisoning predominantly manifest in lots of organs and systems with high oxygen utilization, especially the brain and the heart. The primary aim in oxygen therapy is to eliminate CO and to reduce its toxic effects. In this context, normobaric and hyperbaric oxygen therapy are used to achieve these goals. Normobaric oxygen (NBO treatment is an easily accessible and relatively not expensive modality, where hyperbaric oxygen (HBO therapy requires specific equipment, certified staff and is available only in some centers. Additionally, HBO treatment has several additional advantages over NBO treatment. Despite its benefits, it is compulsory to search for some criteria in selecting patients to be treated because of the limited availability and access of hyperbaric facilities. For an effective evaluation and an optimal treatment, advanced education of the healthcare professionals on the use of oxygen delivery modalities in the management of CO poisoning is imperative. In this review, it has been aimed to outline the significance of oxygen treatment modalities and to determine patient selection criteria for HBO treatment in the management of CO poisoning which continues to be an important threat to community health care. [TAF Prev Med Bull 2011; 10(4.000: 487-494

  2. TCR tuning of T cell subsets.

    Science.gov (United States)

    Cho, Jae-Ho; Sprent, Jonathan

    2018-05-01

    After selection in the thymus, the post-thymic T cell compartments comprise heterogenous subsets of naive and memory T cells that make continuous T cell receptor (TCR) contact with self-ligands bound to major histocompatibility complex (MHC) molecules. T cell recognition of self-MHC ligands elicits covert TCR signaling and is particularly important for controlling survival of naive T cells. Such tonic TCR signaling is tightly controlled and maintains the cells in a quiescent state to avoid autoimmunity. Here, we review how naive and memory T cells are differentially tuned and wired for TCR sensitivity to self and foreign ligands. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  3. Estimation of functional failure probability of passive systems based on subset simulation method

    International Nuclear Information System (INIS)

    Wang Dongqing; Wang Baosheng; Zhang Jianmin; Jiang Jing

    2012-01-01

    In order to solve the problem of multi-dimensional epistemic uncertainties and small functional failure probability of passive systems, an innovative reliability analysis algorithm called subset simulation based on Markov chain Monte Carlo was presented. The method is found on the idea that a small failure probability can be expressed as a product of larger conditional failure probabilities by introducing a proper choice of intermediate failure events. Markov chain Monte Carlo simulation was implemented to efficiently generate conditional samples for estimating the conditional failure probabilities. Taking the AP1000 passive residual heat removal system, for example, the uncertainties related to the model of a passive system and the numerical values of its input parameters were considered in this paper. And then the probability of functional failure was estimated with subset simulation method. The numerical results demonstrate that subset simulation method has the high computing efficiency and excellent computing accuracy compared with traditional probability analysis methods. (authors)

  4. Reconfiguration of NKT Cell Subset Compartment Is Associated with Plaque Development in Patients with Carotid Artery Stenosis.

    Science.gov (United States)

    Cai, Lun; Yu, Lei; Liu, Sa; Li, Tongxun; Zhang, Xiaoping; Cui, Wei; Du, Jie; Zhang, Qinyi

    2017-02-01

    Accumulating evidence shows that immune cells play an important role in carotid atherosclerotic plaque development. In this study, we assessed the association of 6 different natural killer T (NKT) cell subsets, based on CD57 and CD8 expression, with risk for development of carotid atherosclerotic plaque (CAP). Molecular expression by peripheral NKT cells was evaluated in 13 patients with high-risk CAP and control without carotid stenosis (n = 18). High-risk CAP patients, compared with healthy subjects, had less percentage of CD57+CD8- NKT cell subsets (8.64 ± 10.15 versus 19.62 ± 10.8 %; P = 0.01) and CD57+CD8int NKT cell subsets (4.32 ± 3.04 versus 11.87 ± 8.56 %; P = 0.002), with a corresponding increase in the CD57-CD8high NKT cell subsets (33.22 ± 11.87 versus 18.66 ± 13.68 %; P = 0.007). Intracellular cytokine staining showed that CD8+ NKT cell subset was the main cytokine-producing NKT cell. Cytokine production in plasma was measured with Bio-Plex assay. The expression levels of pro-inflammatory mediators (IFN-γ, IL-17, IP-10) were significantly higher in CAP patients as compared to that from controls. These data provide evidence that NKT cell subset compartment reconfiguration in patients with carotid stenosis seems to be associated with the occurrence of carotid atherosclerotic plaque and suggest that both pathogenic and protective NKT cell subsets exist.

  5. Massively-parallel best subset selection for ordinary least-squares regression

    DEFF Research Database (Denmark)

    Gieseke, Fabian; Polsterer, Kai Lars; Mahabal, Ashish

    2017-01-01

    Selecting an optimal subset of k out of d features for linear regression models given n training instances is often considered intractable for feature spaces with hundreds or thousands of dimensions. We propose an efficient massively-parallel implementation for selecting such optimal feature...

  6. A metabolomic approach to the study of wine micro-oxygenation.

    Directory of Open Access Journals (Sweden)

    Panagiotis Arapitsas

    Full Text Available Wine micro-oxygenation is a globally used treatment and its effects were studied here by analysing by untargeted LC-MS the wine metabolomic fingerprint. Eight different procedural variations, marked by the addition of oxygen (four levels and iron (two levels were applied to Sangiovese wine, before and after malolactic fermentation. Data analysis using supervised and unsupervised multivariate methods highlighted some known candidate biomarkers, together with a number of metabolites which had never previously been considered as possible biomarkers for wine micro-oxygenation. Various pigments and tannins were identified among the known candidate biomarkers. Additional new information was obtained suggesting a correlation between oxygen doses and metal contents and changes in the concentration of primary metabolites such as arginine, proline, tryptophan and raffinose, and secondary metabolites such as succinic acid and xanthine. Based on these findings, new hypotheses regarding the formation and reactivity of wine pigment during micro-oxygenation have been proposed. This experiment highlights the feasibility of using unbiased, untargeted metabolomic fingerprinting to improve our understanding of wine chemistry.

  7. A Metabolomic Approach to the Study of Wine Micro-Oxygenation

    Science.gov (United States)

    Arapitsas, Panagiotis; Scholz, Matthias; Vrhovsek, Urska; Di Blasi, Stefano; Biondi Bartolini, Alessandra; Masuero, Domenico; Perenzoni, Daniele; Rigo, Adelio; Mattivi, Fulvio

    2012-01-01

    Wine micro-oxygenation is a globally used treatment and its effects were studied here by analysing by untargeted LC-MS the wine metabolomic fingerprint. Eight different procedural variations, marked by the addition of oxygen (four levels) and iron (two levels) were applied to Sangiovese wine, before and after malolactic fermentation. Data analysis using supervised and unsupervised multivariate methods highlighted some known candidate biomarkers, together with a number of metabolites which had never previously been considered as possible biomarkers for wine micro-oxygenation. Various pigments and tannins were identified among the known candidate biomarkers. Additional new information was obtained suggesting a correlation between oxygen doses and metal contents and changes in the concentration of primary metabolites such as arginine, proline, tryptophan and raffinose, and secondary metabolites such as succinic acid and xanthine. Based on these findings, new hypotheses regarding the formation and reactivity of wine pigment during micro-oxygenation have been proposed. This experiment highlights the feasibility of using unbiased, untargeted metabolomic fingerprinting to improve our understanding of wine chemistry. PMID:22662221

  8. Analysis of Peripheral B Cell Subsets in Patients With Allergic Rhinitis.

    Science.gov (United States)

    Luo, Jing; Guo, Huanhuan; Liu, Zhuofu; Peng, Tao; Hu, Xianting; Han, Miaomiao; Yang, Xiangping; Zhou, Xuhong; Li, Huabin

    2018-05-01

    Recent evidence suggests that B cells can both promote and inhibit the development and progression of allergic disease. However, the characteristics of B cell subsets in patients with allergic rhinitis (AR) have not been well documented. This study aimed to analyze the characteristics of B cell subsets in the peripheral blood of AR patients. Forty-seven AR patients and 54 healthy controls were enrolled in this study, and the B cell subsets in peripheral blood of all subjects were analyzed by flow cytometry. Moreover, the serum total immunoglobulin E (IgE) and IgE concentrations secreted into the cultured peripheral blood mononuclear cells (PBMCs) were measured by using enzyme-linked immunosorbent assay. We found the peripheral blood of AR patients contained higher percentages of memory B cells, plasma cells, and CD19⁺CD24(hi)CD27⁺ regulatory B cells (Bregs) than those of age-matched healthy controls (PB cells and CD19⁺CD24(hi)CD38(hi) Bregs were significantly lower in AR patients than in healthy individuals (PB cells or plasma cells and decreases in CD19⁺CD24(hi)CD38(hi) Breg cells in the peripheral blood. Copyright © 2018 The Korean Academy of Asthma, Allergy and Clinical Immunology · The Korean Academy of Pediatric Allergy and Respiratory Disease.

  9. The total graph of a module with respect to multiplicative-prime subsets

    Directory of Open Access Journals (Sweden)

    H. Heydarinejad Astaneh

    2014-09-01

    Full Text Available Let M be a module over a commutative ring R and U a nonempty proper subset of M. In this paper, a generalization of the total graph T(Γ(M, denoted by T(Γ_U (M is presented, where U is a multiplicative prime subset of M. It is the graph with all elements of M as vertices, and for two distinct elements m, n ∈ M, the vertices m and n are adjacent if and only if m + n ∈ U. The main purpose of this paper is to extend the definitions and properties given in [1] and [10] to a more general case.

  10. Effects of interstitial additions on the structure of Ti5Si3

    International Nuclear Information System (INIS)

    Williams, J. J.; Kramer, M. J.; Akinc, M.; Malik, S. K.

    2000-01-01

    Changes in the structure of Ti 5 Si 3 were measured by x-ray and neutron diffraction as carbon, nitrogen, or oxygen atoms were systematically incorporated into the lattice. Additionally, the lattice parameters and variable atomic positions of pure Ti 5 Si 3 were determined to be a=7.460 Aa, c=5.152 Aa, x Ti =0.2509, and x Si =0.6072. The measured trends in lattice parameters as carbon, nitrogen, or oxygen atoms were added to Ti 5 Si 3 showed that most of the previous studies on supposedly pure Ti 5 Si 3 were actually contaminated by these pervasive light elements. Also, oxygen and carbon additions were shown to strongly draw in the surrounding titanium atoms--evidence for bonding between these atoms. The bonding changes that occurred on addition of carbon, nitrogen, or oxygen acted to decrease the measured anisotropic properties of Ti 5 Si 3 , such as thermal expansion. (c) 2000 Materials Research Society

  11. Enhanced oxygen delivery induced by perfluorocarbon emulsions in capillary tube oxygenators.

    Science.gov (United States)

    Vaslef, S N; Goldstick, T K

    1994-01-01

    Previous studies showed that a new generation of perfluorocarbon (PFC) emulsions increased tissue PO2 in the cat retina to a degree that could not be explained by the small increase in arterial O2 content seen after the infusion of low doses of 1 g PFC/kg body weight. It seems that increased O2 delivery at the tissue level after PFC infusion is caused by a local effect in the microcirculation. The authors studies this effect in vitro at steady state in a closed loop circuit, consisting of one of two types of capillary tube oxygenators, deoxygenator(s), a reservoir bag filled with anticoagulated bovine blood or saline (control), and a roller pump, to see if the addition of PFC would have an effect on the PO2 difference (delta PO2) across the capillary tube membrane oxygenator at a blood flow rate of 3 l/min. Perfluorocarbon was added in three incremental doses, each giving about 0.7 vol% of PFC. The delta PO2 across the oxygenator was measured before and after each dose. The mean percent increases in delta PO2 in blood for two types of oxygenators were 19.2 +/- 8% (mean +/- SD, n = 6, P = 0.002) and 9.9 +/- 4% (n = 3, P = 0.05), respectively, whereas the mean percent change in delta PO2 in saline was -4.9 +/- 2% (n = 2, P = 0.2). Inlet PO2s to the oxygenator were only minimally increased. The authors conclude that O2 delivery was significantly enhanced after injection of PFC in blood in this capillary tube model. A near wall excess of PFC particles may account for the augmentation of O2 diffusion in this model.

  12. Tracking a Subset of Skeleton Joints: An Effective Approach towards Complex Human Activity Recognition

    Directory of Open Access Journals (Sweden)

    Muhammad Latif Anjum

    2017-01-01

    Full Text Available We present a robust algorithm for complex human activity recognition for natural human-robot interaction. The algorithm is based on tracking the position of selected joints in human skeleton. For any given activity, only a few skeleton joints are involved in performing the activity, so a subset of joints contributing the most towards the activity is selected. Our approach of tracking a subset of skeleton joints (instead of tracking the whole skeleton is computationally efficient and provides better recognition accuracy. We have developed both manual and automatic approaches for the selection of these joints. The position of the selected joints is tracked for the duration of the activity and is used to construct feature vectors for each activity. Once the feature vectors have been constructed, we use a Support Vector Machines (SVM multiclass classifier for training and testing the algorithm. The algorithm has been tested on a purposely built dataset of depth videos recorded using Kinect camera. The dataset consists of 250 videos of 10 different activities being performed by different users. Experimental results show classification accuracy of 83% when tracking all skeleton joints, 95% when using manual selection of subset joints, and 89% when using automatic selection of subset joints.

  13. Production of an accelerated oxygen-14 beam

    International Nuclear Information System (INIS)

    Powell, J.; O'Neil, J.P.; Cerny, Joseph

    2003-01-01

    BEARS is an ongoing project to provide a light-ion radioactive-beam capability at the 88-Inch Cyclotron at LBNL. Light radioactive isotopes are produced at a 10 MeV proton medical cyclotron, transported 350 m via a high-speed gas transport capillary, cryogenically separated, and injected into the 88-Inch Cyclotron's ion source. The first radioactive beam successfully accelerated was carbon-11 and beams of intensity more than 10 8 ions/s have been utilized for experiments. Development of oxygen-14 as the second BEARS beam presented considerable technical challenges, both due to its short half-life of 71 s and the radiation chemistry of oxygen in the target. The usual techniques developed for medical uses of oxygen-15 involve the addition of significant amounts of carrier oxygen, something that would overload the ion source. As a solution, oxygen-14 is produced as water in a carrier-free form, and is chemically converted in two steps to carbon dioxide, a form readily usable by the BEARS. This system has been built and is operational, and initial tests of accelerating an oxygen-14 beam have been performed

  14. Improvement of AD Biosynthesis Response to Enhanced Oxygen Transfer by Oxygen Vectors in Mycobacterium neoaurum TCCC 11979.

    Science.gov (United States)

    Su, Liqiu; Shen, Yanbing; Gao, Tian; Luo, Jianmei; Wang, Min

    2017-08-01

    In steroid biotransformation, soybean oil can improve the productivity of steroids by increasing substrate solubility and strengthen the cell membrane permeability. However, little is known of its role as oxygen carrier and its mechanism of promoting the steroid biotransformation. In this work, soybean oil used as oxygen vector for the enhancement of androst-4-ene-3,17-dione (AD) production by Mycobacterium neoaurum TCCC 11979 (MNR) was investigated. Upon the addition of 16% (v/v) soybean oil, the volumetric oxygen transfer coefficient (K L a) value increased by 44%, and the peak molar yield of AD (55.76%) was achieved. Analysis of intracellular cofactor levels showed high NAD + , ATP level, and a low NADH/NAD + ratio. Meanwhile, the two key enzymes of the tricarboxylic acid (TCA) cycle, namely, isocitrate dehydrogenase and α-ketoglutarate dehydrogenase, were upregulated after incubation with soybean oil. These enhancements induced by the increasing of oxygen supply showed positive effects on phytosterol (PS) bioconversion. Results could contribute to the understanding of effects of soybean oil as oxygen vector on steroid biotransformation and provided a convenient method for enhancing the efficiency of aerobic steroid biocatalysis.

  15. Phenotypic and functional characterization of earthworm coelomocyte subsets

    DEFF Research Database (Denmark)

    Engelmann, Péter; Hayashi, Yuya; Bodo, Kornélia

    2016-01-01

    Flow cytometry is a common approach to study invertebrate immune cells including earthworm coelomocytes. However, the link between light-scatter- and microscopy-based phenotyping remains obscured. Here we show, by means of light scatter-based cell sorting, both subpopulations (amoebocytes...... amoebocytes and eleocytes, with the former being in favor of bacterial engulfment. This study has proved successful in linking flow cytometry and microscopy analysis and provides further experimental evidence of phenotypic and functional heterogeneity in earthworm coelomocyte subsets....

  16. Study of the effect of heat treatments and the addition of oxygen on the microstructure and mechanical properties of Ti-15Mo alloy used as biomaterials

    International Nuclear Information System (INIS)

    Martins Junior, J.R.S.; Araujo, R.O.; Nogueira, R.A.; Grandini, C.R.; Claro, A.P.R.A.

    2010-01-01

    The Ti-15Mo alloy has its mechanical properties strongly modified by heat treatments and the addition of interstitial elements such as oxygen, for example. In this sense, the objective of this paper is to evaluate the effect of heat treatment and the introduction of oxygen on the microstructure and mechanical properties of Ti-15% pMo alloy. The samples used in this work consist of Ti containing 15% in weight of molybdenum, which were characterized by density measurements, X-ray diffraction, optical and scanning electron microscopy, microhardness and mechanical spectroscopy. The diffraction patterns were analyzed by Rietveld method, where it was possible to obtain the lattice parameters and the amount (in %) of each phase present in the microstructure. The results of optical and scanning electron microscopy are consistent with the X-ray diffraction, showing a predominance of structures of the beta type. The elasticity modulus obtained was about 90 GPa, indicating that this is a promising alloy for use in dental implants. (author)

  17. High Aldehyde Dehydrogenase Activity Identifies a Subset of Human Mesenchymal Stromal Cells with Vascular Regenerative Potential.

    Science.gov (United States)

    Sherman, Stephen E; Kuljanin, Miljan; Cooper, Tyler T; Putman, David M; Lajoie, Gilles A; Hess, David A

    2017-06-01

    During culture expansion, multipotent mesenchymal stromal cells (MSCs) differentially express aldehyde dehydrogenase (ALDH), an intracellular detoxification enzyme that protects long-lived cells against oxidative stress. Thus, MSC selection based on ALDH-activity may be used to reduce heterogeneity and distinguish MSC subsets with improved regenerative potency. After expansion of human bone marrow-derived MSCs, cell progeny was purified based on low versus high ALDH-activity (ALDH hi ) by fluorescence-activated cell sorting, and each subset was compared for multipotent stromal and provascular regenerative functions. Both ALDH l ° and ALDH hi MSC subsets demonstrated similar expression of stromal cell (>95% CD73 + , CD90 + , CD105 + ) and pericyte (>95% CD146 + ) surface markers and showed multipotent differentiation into bone, cartilage, and adipose cells in vitro. Conditioned media (CDM) generated by ALDH hi MSCs demonstrated a potent proliferative and prosurvival effect on human microvascular endothelial cells (HMVECs) under serum-free conditions and augmented HMVEC tube-forming capacity in growth factor-reduced matrices. After subcutaneous transplantation within directed in vivo angiogenesis assay implants into immunodeficient mice, ALDH hi MSC or CDM produced by ALDH hi MSC significantly augmented murine vascular cell recruitment and perfused vessel infiltration compared with ALDH l ° MSC. Although both subsets demonstrated strikingly similar mRNA expression patterns, quantitative proteomic analyses performed on subset-specific CDM revealed the ALDH hi MSC subset uniquely secreted multiple proangiogenic cytokines (vascular endothelial growth factor beta, platelet derived growth factor alpha, and angiogenin) and actively produced multiple factors with chemoattractant (transforming growth factor-β, C-X-C motif chemokine ligand 1, 2, and 3 (GRO), C-C motif chemokine ligand 5 (RANTES), monocyte chemotactic protein 1 (MCP-1), interleukin [IL]-6, IL-8) and matrix

  18. Monocyte Subsets in Schistosomiasis Patients with Periportal Fibrosis

    Directory of Open Access Journals (Sweden)

    Jamille Souza Fernandes

    2014-01-01

    Full Text Available A major issue with Schistosoma mansoni infection is the development of periportal fibrosis, which is predominantly caused by the host immune response to egg antigens. Experimental studies have pointed to the participation of monocytes in the pathogenesis of liver fibrosis. The aim of this study was to characterize the subsets of monocytes in individuals with different degrees of periportal fibrosis secondary to schistosomiasis. Monocytes were classified into classical (CD14++CD16−, intermediate (CD14++CD16+, and nonclassical (CD14+CD16++. The expressions of monocyte markers and cytokines were assessed using flow cytometry. The frequency of classical monocytes was higher than the other subsets. The expression of HLA-DR, IL-6, TNF-α, and TGF-β was higher in monocytes from individuals with moderate to severe fibrosis as compared to other groups. Although no differences were observed in receptors expression (IL-4R and IL-10R between groups of patients, the expression of IL-12 was lower in monocytes from individuals with moderate to severe fibrosis, suggesting a protective role of this cytokine in the development of fibrosis. Our data support the hypothesis that the three different monocyte populations participate in the immunopathogenesis of periportal fibrosis, since they express high levels of proinflammatory and profibrotic cytokines and low levels of regulatory markers.

  19. Production of an accelerated oxygen-14 beam

    CERN Document Server

    Powell, J; Cerny, J

    2003-01-01

    BEARS is an ongoing project to provide a light-ion radioactive-beam capability at the 88-Inch Cyclotron at LBNL. Light radioactive isotopes are produced at a 10 MeV proton medical cyclotron, transported 350 m via a high-speed gas transport capillary, cryogenically separated, and injected into the 88-Inch Cyclotron's ion source. The first radioactive beam successfully accelerated was carbon-11 and beams of intensity more than 10 sup 8 ions/s have been utilized for experiments. Development of oxygen-14 as the second BEARS beam presented considerable technical challenges, both due to its short half-life of 71 s and the radiation chemistry of oxygen in the target. The usual techniques developed for medical uses of oxygen-15 involve the addition of significant amounts of carrier oxygen, something that would overload the ion source. As a solution, oxygen-14 is produced as water in a carrier-free form, and is chemically converted in two steps to carbon dioxide, a form readily usable by the BEARS. This system has bee...

  20. Selecting a climate model subset to optimise key ensemble properties

    Directory of Open Access Journals (Sweden)

    N. Herger

    2018-02-01

    Full Text Available End users studying impacts and risks caused by human-induced climate change are often presented with large multi-model ensembles of climate projections whose composition and size are arbitrarily determined. An efficient and versatile method that finds a subset which maintains certain key properties from the full ensemble is needed, but very little work has been done in this area. Therefore, users typically make their own somewhat subjective subset choices and commonly use the equally weighted model mean as a best estimate. However, different climate model simulations cannot necessarily be regarded as independent estimates due to the presence of duplicated code and shared development history. Here, we present an efficient and flexible tool that makes better use of the ensemble as a whole by finding a subset with improved mean performance compared to the multi-model mean while at the same time maintaining the spread and addressing the problem of model interdependence. Out-of-sample skill and reliability are demonstrated using model-as-truth experiments. This approach is illustrated with one set of optimisation criteria but we also highlight the flexibility of cost functions, depending on the focus of different users. The technique is useful for a range of applications that, for example, minimise present-day bias to obtain an accurate ensemble mean, reduce dependence in ensemble spread, maximise future spread, ensure good performance of individual models in an ensemble, reduce the ensemble size while maintaining important ensemble characteristics, or optimise several of these at the same time. As in any calibration exercise, the final ensemble is sensitive to the metric, observational product, and pre-processing steps used.

  1. Selecting a climate model subset to optimise key ensemble properties

    Science.gov (United States)

    Herger, Nadja; Abramowitz, Gab; Knutti, Reto; Angélil, Oliver; Lehmann, Karsten; Sanderson, Benjamin M.

    2018-02-01

    End users studying impacts and risks caused by human-induced climate change are often presented with large multi-model ensembles of climate projections whose composition and size are arbitrarily determined. An efficient and versatile method that finds a subset which maintains certain key properties from the full ensemble is needed, but very little work has been done in this area. Therefore, users typically make their own somewhat subjective subset choices and commonly use the equally weighted model mean as a best estimate. However, different climate model simulations cannot necessarily be regarded as independent estimates due to the presence of duplicated code and shared development history. Here, we present an efficient and flexible tool that makes better use of the ensemble as a whole by finding a subset with improved mean performance compared to the multi-model mean while at the same time maintaining the spread and addressing the problem of model interdependence. Out-of-sample skill and reliability are demonstrated using model-as-truth experiments. This approach is illustrated with one set of optimisation criteria but we also highlight the flexibility of cost functions, depending on the focus of different users. The technique is useful for a range of applications that, for example, minimise present-day bias to obtain an accurate ensemble mean, reduce dependence in ensemble spread, maximise future spread, ensure good performance of individual models in an ensemble, reduce the ensemble size while maintaining important ensemble characteristics, or optimise several of these at the same time. As in any calibration exercise, the final ensemble is sensitive to the metric, observational product, and pre-processing steps used.

  2. Cytokine profile and lymphocyte subsets in type 2 diabetes

    Directory of Open Access Journals (Sweden)

    C.O. Francisco

    2016-01-01

    Full Text Available Type 2 diabetes mellitus (T2D is a metabolic disease with inflammation as an important pathogenic background. However, the pattern of immune cell subsets and the cytokine profile associated with development of T2D are unclear. The objective of this study was to evaluate different components of the immune system in T2D patients' peripheral blood by quantifying the frequency of lymphocyte subsets and intracellular pro- and anti-inflammatory cytokine production by T cells. Clinical data and blood samples were collected from 22 men (51.6±6.3 years old with T2D and 20 nonsmoking men (49.4±7.6 years old who were matched for age and sex as control subjects. Glycated hemoglobin, high-sensitivity C-reactive protein concentrations, and the lipid profile were measured by a commercially available automated system. Frequencies of lymphocyte subsets in peripheral blood and intracellular production of interleukin (IL-4, IL-10, IL-17, tumor necrosis factor-α, and interferon-γ cytokines by CD3+ T cells were assessed by flow cytometry. No differences were observed in the frequency of CD19+ B cells, CD3+CD8+ and CD3+CD4+ T cells, CD16+56+ NK cells, and CD4+CD25+Foxp3+ T regulatory cells in patients with T2D compared with controls. The numbers of IL-10- and IL-17-producing CD3+ T cells were significantly higher in patients with T2D than in controls (P<0.05. The frequency of interferon-γ-producing CD3+ T cells was positively correlated with body mass index (r=0.59; P=0.01. In conclusion, this study shows increased numbers of circulating IL-10- and IL-17-producing CD3+ T cells in patients with T2D, suggesting that these cytokines are involved in the immune pathology of this disease.

  3. Singlet oxygen treatment of tumor cells triggers extracellular singlet oxygen generation, catalase inactivation and reactivation of intercellular apoptosis-inducing signaling☆

    Science.gov (United States)

    Riethmüller, Michaela; Burger, Nils; Bauer, Georg

    2015-01-01

    Intracellular singlet oxygen generation in photofrin-loaded cells caused cell death without discrimination between nonmalignant and malignant cells. In contrast, extracellular singlet oxygen generation caused apoptosis induction selectively in tumor cells through singlet oxygen-mediated inactivation of tumor cell protective catalase and subsequent reactivation of intercellular ROS-mediated apoptosis signaling through the HOCl and the NO/peroxynitrite signaling pathway. Singlet oxygen generation by extracellular photofrin alone was, however, not sufficient for optimal direct inactivation of catalase, but needed to trigger the generation of cell-derived extracellular singlet oxygen through the interaction between H2O2 and peroxynitrite. Thereby, formation of peroxynitrous acid, generation of hydroxyl radicals and formation of perhydroxyl radicals (HO2.) through hydroxyl radical/H2O2 interaction seemed to be required as intermediate steps. This amplificatory mechanism led to the formation of singlet oxygen at a sufficiently high concentration for optimal inactivation of membrane-associated catalase. At low initial concentrations of singlet oxygen, an additional amplification step needed to be activated. It depended on singlet oxygen-dependent activation of the FAS receptor and caspase-8, followed by caspase-8-mediated enhancement of NOX activity. The biochemical mechanisms described here might be considered as promising principle for the development of novel approaches in tumor therapy that specifically direct membrane-associated catalase of tumor cells and thus utilize tumor cell-specific apoptosis-inducing ROS signaling. PMID:26225731

  4. SOCP relaxation bounds for the optimal subset selection problem applied to robust linear regression

    OpenAIRE

    Flores, Salvador

    2015-01-01

    This paper deals with the problem of finding the globally optimal subset of h elements from a larger set of n elements in d space dimensions so as to minimize a quadratic criterion, with an special emphasis on applications to computing the Least Trimmed Squares Estimator (LTSE) for robust regression. The computation of the LTSE is a challenging subset selection problem involving a nonlinear program with continuous and binary variables, linked in a highly nonlinear fashion. The selection of a ...

  5. 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...

  6. Oxygen toxicity

    Directory of Open Access Journals (Sweden)

    C. A. van der Westhuizen

    1990-07-01

    Full Text Available Oxygen has been discovered about 200 years ago. Since then the vital physiological involvement of oxygen in various biologi­cal processes, mainly energy production, has been established. However, in the body molecular oxygen can be converted to toxic oxygen metabolites such as superoxide anion, hydrogen peroxide, the hydroxyl radical and singlet oxygen. These toxic metabolites are produced mainly in the mitochondria, plasma membranes and endoplasmic reticulum.

  7. a Study of Oxygen Precipitation in Heavily Doped Silicon.

    Science.gov (United States)

    Graupner, Robert Kurt

    Gettering of impurities with oxygen precipitates is widely used during the fabrication of semiconductors to improve the performance and yield of the devices. Since the effectiveness of the gettering process is largely dependent on the initial interstitial oxygen concentration, accurate measurements of this parameter are of considerable importance. Measurements of interstitial oxygen following thermal cycles are required for development of semiconductor fabrication processes and for research into the mechanisms of oxygen precipitate nucleation and growth. Efforts by industrial associations have led to the development of standard procedures for the measurement of interstitial oxygen in wafers. However practical oxygen measurements often do not satisfy the requirements of such standard procedures. An additional difficulty arises when the silicon wafer has a low resitivity (high dopant concentration). In such cases the infrared light used for the measurement is severely attenuated by the electrons of holes introduced by the dopant. Since such wafers are the substrates used for the production of widely used epitaxial wafers, this measurement problem is economically important. Alternative methods such as Secondary Ion Mass Spectroscopy or Gas Fusion Analysis have been developed to measure oxygen in these cases. However, neither of these methods is capable of distinguishing interstitial oxygen from precipitated oxygen as required for precipitation studies. In addition to the commercial interest in heavily doped silicon substrates, they are also of interest for research into the role of point defects in nucleation and precipitation processes. Despite considerable research effort, there is still disagreement concerning the type of point defect and its role in semiconductor processes. Studies of changes in the interstitial oxygen concentration of heavily doped and lightly doped silicon wafers could help clarify the role of point defects in oxygen nucleation and precipitation

  8. Accelerated time-of-flight (TOF) PET image reconstruction using TOF bin subsetization and TOF weighting matrix pre-computation

    International Nuclear Information System (INIS)

    Mehranian, Abolfazl; Kotasidis, Fotis; Zaidi, Habib

    2016-01-01

    Time-of-flight (TOF) positron emission tomography (PET) technology has recently regained popularity in clinical PET studies for improving image quality and lesion detectability. Using TOF information, the spatial location of annihilation events is confined to a number of image voxels along each line of response, thereby the cross-dependencies of image voxels are reduced, which in turns results in improved signal-to-noise ratio and convergence rate. In this work, we propose a novel approach to further improve the convergence of the expectation maximization (EM)-based TOF PET image reconstruction algorithm through subsetization of emission data over TOF bins as well as azimuthal bins. Given the prevalence of TOF PET, we elaborated the practical and efficient implementation of TOF PET image reconstruction through the pre-computation of TOF weighting coefficients while exploiting the same in-plane and axial symmetries used in pre-computation of geometric system matrix. In the proposed subsetization approach, TOF PET data were partitioned into a number of interleaved TOF subsets, with the aim of reducing the spatial coupling of TOF bins and therefore to improve the convergence of the standard maximum likelihood expectation maximization (MLEM) and ordered subsets EM (OSEM) algorithms. The comparison of on-the-fly and pre-computed TOF projections showed that the pre-computation of the TOF weighting coefficients can considerably reduce the computation time of TOF PET image reconstruction. The convergence rate and bias-variance performance of the proposed TOF subsetization scheme were evaluated using simulated, experimental phantom and clinical studies. Simulations demonstrated that as the number of TOF subsets is increased, the convergence rate of MLEM and OSEM algorithms is improved. It was also found that for the same computation time, the proposed subsetization gives rise to further convergence. The bias-variance analysis of the experimental NEMA phantom and a clinical

  9. Lymphocytic subsets and low-dose exposure

    International Nuclear Information System (INIS)

    Tuschl, H.; Kovac, R.; Eybl, E.

    1993-03-01

    The present investigations proved the differential radiosensitivity of lymphocytic subpopulations: From in vivo and in vitro irradiations it may be followed that the most sensitive subset are CD8 positive suppressor T cells. CD4/CD8 ratios are increased both in peripheral blood and after mitogen stimulation of lymphocytes of exposed persons. The decrease in B cells is pronounced only at higher radiation doses. Though the rate of DNA synthesis after mitogen stimulation was reduced in some exposed persons, that was no general phenomenon. Especially after tritium exposure, the observed lymphopenia correlated with an increased stimulation by PHA and an increased rate of DNA synthesis in some probands. Thus the present investigations indicate that - despite an inhibition of some immune parameters by radioexposure - the body is able to maintain its immunological homoeostasis. (authors)

  10. Reactive oxygen species and nitric oxide signaling in bystander cells.

    Science.gov (United States)

    Jella, Kishore Kumar; Moriarty, Roisin; McClean, Brendan; Byrne, Hugh J; Lyng, Fiona M

    2018-01-01

    It is now well accepted that radiation induced bystander effects can occur in cells exposed to media from irradiated cells. The aim of this study was to follow the bystander cells in real time following addition of media from irradiated cells and to determine the effect of inhibiting these signals. A human keratinocyte cell line, HaCaT cells, was irradiated (0.005, 0.05 and 0.5 Gy) with γ irradiation, conditioned medium was harvested after one hour and added to recipient bystander cells. Reactive oxygen species, nitric oxide, Glutathione levels, caspase activation, cytotoxicity and cell viability was measured after the addition of irradiated cell conditioned media to bystander cells. Reactive oxygen species and nitric oxide levels in bystander cells treated with 0.5Gy ICCM were analysed in real time using time lapse fluorescence microscopy. The levels of reactive oxygen species were also measured in real time after the addition of extracellular signal-regulated kinase and c-Jun amino-terminal kinase pathway inhibitors. ROS and glutathione levels were observed to increase after the addition of irradiated cell conditioned media (0.005, 0.05 and 0.5 Gy ICCM). Caspase activation was found to increase 4 hours after irradiated cell conditioned media treatment (0.005, 0.05 and 0.5 Gy ICCM) and this increase was observed up to 8 hours and there after a reduction in caspase activation was observed. A decrease in cell viability was observed but no major change in cytotoxicity was found in HaCaT cells after treatment with irradiated cell conditioned media (0.005, 0.05 and 0.5 Gy ICCM). This study involved the identification of key signaling molecules such as reactive oxygen species, nitric oxide, glutathione and caspases generated in bystander cells. These results suggest a clear connection between reactive oxygen species and cell survival pathways with persistent production of reactive oxygen species and nitric oxide in bystander cells following exposure to irradiated cell

  11. Mixed oxygen ion/electron-conducting ceramics for oxygen separation

    Energy Technology Data Exchange (ETDEWEB)

    Stevenson, J.W.; Armstrong, T.R.; Armstrong, B.L. [Pacific Northwest National Lab., Richland, WA (United States)

    1996-08-01

    Mixed oxygen ion and electron-conducting ceramics are unique materials that can passively separate high purity oxygen from air. Oxygen ions move through a fully dense ceramic in response to an oxygen concentration gradient, charge-compensated by an electron flux in the opposite direction. Compositions in the system La{sub 1{minus}x}M{sub x}Co{sub 1{minus}y{minus}z}Fe{sub y}N{sub z}O{sub 3{minus}{delta}}, perovskites where M=Sr, Ca, and Ba, and N=Mn, Ni, Cu, Ti, and Al, have been prepared and their electrical, oxygen permeation, oxygen vacancy equilibria, and catalytic properties evaluated. Tubular forms, disks, and asymmetric membrane structures, a thin dense layer on a porous support of the same composition, have been fabricated for testing purposes. In an oxygen partial gradient, the passive oxygen flux through fully dense structures was highly dependent on composition. An increase in oxygen permeation with increased temperature is attributed to both enhanced oxygen vacancy mobility and higher vacancy populations. Highly acceptor-doped compositions resulted in oxygen ion mobilities more than an order of magnitude higher than yttria-stabilized zirconia. The mixed conducting ceramics have been utilized in a membrane reactor configuration to upgrade methane to ethane and ethylene. Conditions were established to balance selectivity and throughput in a catalytic membrane reactor constructed from mixed conducting ceramics.

  12. Correction of abnormal B-cell subset distribution by interleukin-6 receptor blockade in polymyalgia rheumatica.

    Science.gov (United States)

    Carvajal Alegria, Guillermo; Devauchelle-Pensec, Valérie; Renaudineau, Yves; Saraux, Alain; Pers, Jacques-Olivier; Cornec, Divi

    2017-08-01

    The aim was to study lymphocyte subsets and circulating cytokines at diagnosis of PMR and after tocilizumab monotherapy. Eighteen untreated patients with PMR were included in a prospective study and received 3-monthly tocilizumab infusions without glucocorticoids. Lymphocyte subset distribution was assessed by flow cytometry and serum cytokines were assayed by a 34-cytokine array and ELISA, at baseline and during follow-up. Baseline data were also compared with age- and sex-matched controls. At baseline, total lymphocytes, T-cell subsets and NK cell counts were similar in patients and controls, but patients had significantly lower B-cell counts attributable to lower transitional, naïve and post-switch memory B-cell subsets. Circulating B-cell counts were positively correlated with the PMR activity score (PMR-AS) in untreated active patients at baseline, but subsequently increased to normal values while disease activity was controlled after tocilizumab therapy. Among serum cytokines, IL-6 showed the largest concentration difference between patients and controls, and the serum IL-6 concentration was correlated with baseline PMR-AS. The effects of tocilizumab on serum IL-6 concentration were heterogeneous, and the patients whose serum IL-6 decreased after tocilizumab therapy exhibited a significant increase in circulating B-cell counts. In patients with PMR, B-cell lymphopenia and abnormal B-cell subset distribution are associated with disease activity and IL-6 concentration, and both are corrected by the IL-6 antagonist tocilizumab. © The Author 2017. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oup.com

  13. NKT-cell subsets: promoters and protectors in inflammatory liver disease.

    Science.gov (United States)

    Kumar, Vipin

    2013-09-01

    Natural killer T cells (NKT) are innate-like cells which are abundant in liver sinusoids and express the cell surface receptors of NK cells (e.g., NK1.1 (mouse) or CD161+/CD56+(human)) as well as an antigen receptor (TCR) characteristic of conventional T cells. NKT cells recognize lipid antigens in the context of CD1d, a non-polymorphic MHC class I-like molecule. Activation of NKT cells has a profound influence on the immune response against tumors and infectious organisms and in autoimmune diseases. NKT cells can be categorized into at least two distinct subsets: iNKT or type I use a semi-invariant TCR, whereas type II NKT TCRs are more diverse. Recent evidence suggests that NKT-cell subsets can play opposing roles early in non-microbial liver inflammation in that type I NKT are proinflammatory whereas type II NKT cells inhibit type I NKT-mediated liver injury. Copyright © 2013 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

  14. Three distinct developmental pathways for adaptive and two IFN-γ-producing γδ T subsets in adult thymus

    DEFF Research Database (Denmark)

    Buus, Terkild Brink; Ødum, Niels; Geisler, Carsten

    2017-01-01

    -producing γδ T cells (γδNKT). Developmental progression towards both IFN-γ-producing subsets can be induced by TCR signalling, and each pathway results in thymic emigration at a different stage. Finally, we show that γδT1 cells are the predominating IFN-γ-producing subset developing in the adult thymus. Thus......, this study maps out three distinct development pathways that result in the programming of γδTn, γδT1 and γδNKT cells.......Murine γδ T cells include subsets that are programmed for distinct effector functions during their development in the thymus. Under pathological conditions, different γδ T cell subsets can be protective or can exacerbate a disease. Here we show that CD117, CD200 and CD371, together with other...

  15. SU-E-T-274: Does Atmospheric Oxygen Affect the PRESAGE Dosimeter?

    Energy Technology Data Exchange (ETDEWEB)

    Alqathami, M; Ibbott, G [UT MD Anderson Cancer Center, Houston, TX (United States); Blencowe, A [The University of South Australia, South Australia, SA (Australia)

    2015-06-15

    Purpose: To experimentally determine the influence of atmospheric oxygen on the efficiency of the PRESAGE dosimeter and its reporting system. Methods: Batches of the reporting system – a mixture of chloroform and leuchomalachite green dye – and PRESAGE were prepared in aerobic and anaerobic conditions. For anaerobic batches, samples were deoxygenated by bubbling nitrogen through the dosimeter precursors or reporting system for 10 min. The dosimeters and reporting systems were prepared in spectrophotometric cuvettes and glass vials, respectively, and were irradiated with 6 MV photons to various radiation doses using a clinical linear accelerator. Changes in optical density of the dosimeters and reporting system before and after irradiation were measured using a spectrophotometer. In addition, the concentrations of dissolved oxygen were measured using a dissolved oxygen meter. Results: The experiments revealed that oxygen has little influence on the characteristics of PRESAGE, with the radical initiator oxidizing the leucomalachite green even in the presence of oxygen. However, deoxygenation of the reporting system leads to an increase in sensitivity to radiation dose by ∼ 30% when compared to the non-deoxygenated system. A slight improvement in sensitivity (∼ 5%) was also achieved by deoxygenating the PRESAGE precursor prior to casting. Measurement of the dissolved oxygen revealed low levels (0.4 ppm) in the polyurethane precursor used to fabricate the dosimeters, as compared to water (8.6 ppm). In addition, deoxygenation had no effect on the retention of the post-response absorption value of the PRESAGE dosimeter. Conclusion: The results suggest that the presence of oxygen does not inhibit the radiochromic properties of the PRESAGE system. In addition, there were no observed changes in the dose linearity, absorption spectrum and post-response photofading characteristics of the PRESAGE under the conditions investigated.

  16. Effects of Cyanate and 2,3-Diphosphoglycerate on Sickling RELATIONSHIP TO OXYGENATION

    Science.gov (United States)

    Jensen, Michael; Bunn, H. Franklin; Halikas, George; Kan, Yuet Wai; Nathan, David G.

    1973-01-01

    Cyanate and 2,3-diphosphoglycerate (2,3-DPG) both influence the oxygen affinity of hemoglobin. The studies presented here concern the effects of these compounds on the sickling phenomenon. The inhibitory effect of cyanate on sickling is largely due to the fact that it increases the percentage of oxyhemoglobin S at a given oxygen tension. In addition, cyanate inhibits sickling by a mechanism that is independent of oxygenation. In this paper, we have demonstrated that the viscosity of carbamylated sickle blood was lower than that of non-carbamylated controls at the same oxygen saturation. Furthermore, carbamylation resulted in an increase in the minimum concentration of deoxy-sickle hemoglobin required for gelation. Like cyanate, 2,3-DPG affected sickling of intact erythrocytes by two mechanisms. Since 2,3-DPG decreases the percentage of oxyhemoglobin S at a given oxygen tension, sickling is enhanced. In addition, 2,3-DPG had a direct effect. When the intracellular 2,3-DPG concentration was increased in vitro, a greater percentage of cells were sickled at a given oxygen saturation. Conversely, sickling was inhibited in cells in which 2,3-DPG was artificially lowered. These data indicate that the enhancement of sickling by 2,3-DPG is in part independent of its influence on oxygen affinity. PMID:4729047

  17. Closed Loop Control of Oxygen Delivery and Oxygen Generation

    Science.gov (United States)

    2017-08-01

    were used for this study and were connected via a USB cable to allow communication. The ventilator was modified to allow closed loop control of oxygen...connected via a USB cable to allow communication. The ventilator was modified to allow closed loop control of oxygen based on the oxygen saturation...2017-4119, 28 Aug 2017. oximetry (SpO2) and intermittent arterial blood sampling for arterial oxygen tension (partial pressure of oxygen [PaO2]) and

  18. POLDER/Parasol L2 Radiation Budget subset along CloudSat track V001 (PARASOLRB_CPR) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — This is the POLDER/Parasol Level-2 Radiation Budget Subset, collocated with the CloudSat track. The subset is processed at the A-Train Data Depot of the GES DISC,...

  19. Singlet oxygen treatment of tumor cells triggers extracellular singlet oxygen generation, catalase inactivation and reactivation of intercellular apoptosis-inducing signaling.

    Science.gov (United States)

    Riethmüller, Michaela; Burger, Nils; Bauer, Georg

    2015-12-01

    Intracellular singlet oxygen generation in photofrin-loaded cells caused cell death without discrimination between nonmalignant and malignant cells. In contrast, extracellular singlet oxygen generation caused apoptosis induction selectively in tumor cells through singlet oxygen-mediated inactivation of tumor cell protective catalase and subsequent reactivation of intercellular ROS-mediated apoptosis signaling through the HOCl and the NO/peroxynitrite signaling pathway. Singlet oxygen generation by extracellular photofrin alone was, however, not sufficient for optimal direct inactivation of catalase, but needed to trigger the generation of cell-derived extracellular singlet oxygen through the interaction between H2O2 and peroxynitrite. Thereby, formation of peroxynitrous acid, generation of hydroxyl radicals and formation of perhydroxyl radicals (HO2(.)) through hydroxyl radical/H2O2 interaction seemed to be required as intermediate steps. This amplificatory mechanism led to the formation of singlet oxygen at a sufficiently high concentration for optimal inactivation of membrane-associated catalase. At low initial concentrations of singlet oxygen, an additional amplification step needed to be activated. It depended on singlet oxygen-dependent activation of the FAS receptor and caspase-8, followed by caspase-8-mediated enhancement of NOX activity. The biochemical mechanisms described here might be considered as promising principle for the development of novel approaches in tumor therapy that specifically direct membrane-associated catalase of tumor cells and thus utilize tumor cell-specific apoptosis-inducing ROS signaling. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  20. 40 CFR 80.35 - Labeling of retail gasoline pumps; oxygenated gasoline.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Labeling of retail gasoline pumps; oxygenated gasoline. 80.35 Section 80.35 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Oxygenated Gasoline § 80.35 Labeling...

  1. Carbonic anhydrase inhibition increases retinal oxygen tension and dilates retinal vessels

    DEFF Research Database (Denmark)

    Pedersen, Daniella Bach; Koch Jensen, Peter; la Cour, Morten

    2005-01-01

    Carbonic anhydrase inhibitors (CAIs) increase blood flow in the brain and probably also in the optic nerve and retina. Additionally they elevate the oxygen tension in the optic nerve in the pig. We propose that they also raise the oxygen tension in the retina. We studied the oxygen tension in the...... in the pig retina and optic nerve before and after dorzolamide injection. Also the retinal vessel diameters during carbonic anhydrase inhibition were studied....

  2. High-Energy-Density Metal-Oxygen Batteries: Lithium-Oxygen Batteries vs Sodium-Oxygen Batteries.

    Science.gov (United States)

    Song, Kyeongse; Agyeman, Daniel Adjei; Park, Mihui; Yang, Junghoon; Kang, Yong-Mook

    2017-12-01

    The development of next-generation energy-storage devices with high power, high energy density, and safety is critical for the success of large-scale energy-storage systems (ESSs), such as electric vehicles. Rechargeable sodium-oxygen (Na-O 2 ) batteries offer a new and promising opportunity for low-cost, high-energy-density, and relatively efficient electrochemical systems. Although the specific energy density of the Na-O 2 battery is lower than that of the lithium-oxygen (Li-O 2 ) battery, the abundance and low cost of sodium resources offer major advantages for its practical application in the near future. However, little has so far been reported regarding the cell chemistry, to explain the rate-limiting parameters and the corresponding low round-trip efficiency and cycle degradation. Consequently, an elucidation of the reaction mechanism is needed for both lithium-oxygen and sodium-oxygen cells. An in-depth understanding of the differences and similarities between Li-O 2 and Na-O 2 battery systems, in terms of thermodynamics and a structural viewpoint, will be meaningful to promote the development of advanced metal-oxygen batteries. State-of-the-art battery design principles for high-energy-density lithium-oxygen and sodium-oxygen batteries are thus reviewed in depth here. Major drawbacks, reaction mechanisms, and recent strategies to improve performance are also summarized. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Oxygen Therapy

    Directory of Open Access Journals (Sweden)

    Bonnie Solmes

    2000-01-01

    Full Text Available LTOT is prescribed for people with chronic lung disease in whom there is a decrease in the ability of the lungs to supply enough oxygen to the body. The heart is obliged to pump faster to meet the body's oxygen requirements. This may place undue stress on the heart, resulting in palpitations, dizziness and fatigue. A low oxygen level in arterial blood is also harmful to the heart, the brain and the pulmonary blood vessels. Oxygen therapy is used to break this cycle. A person with low blood oxygen will often be able to accomplish more with less fatigue with the help of supplemental oxygen therapy. Shortness of breath is a mechanical problem resulting from the effects of chronic obstructive pulmonary disease. Oxygen therapy may or may not reduce shortness of breath, but it will help the lungs and heart to function with less stress.

  4. Oxygen concentration diffusion analysis of lead-bismuth-cooled, natural-circulation reactor

    International Nuclear Information System (INIS)

    Ito, Kei; Sakai, Takaaki

    2001-11-01

    The feasibility study on fast breeder reactors in Japan has been conducted at JNC and related organizations. The Phase-I study has finished in March, 2001. During the Phase-I activity, lead-bismuth eutectic coolant has been selected as one of the possible coolant options and a medium-scale plant, cooled by a lead-bismuth natural circulation flow was studied. On the other side, it is known that lead-bismuth eutectic has a problem of structural material corrosiveness. It was found that oxygen concentration control in the eutectic plays an important role on the corrosion protection. In this report, we have developed a concentration diffusion analysis code (COCOA: COncentration COntrol Analysis code) in order to carry out the oxygen concentration control analysis. This code solves a two-dimensional concentration diffusion equation by the finite differential method. It is possible to simulate reaction of oxygen and hydrogen by the code. We verified the basic performance of the code and carried out oxygen concentration diffusion analysis for the case of an oxygen increase by a refueling process in the natural circulation reactor. In addition, characteristics of the oxygen control system was discussed for a different type of the control system as well. It is concluded that the COCOA code can simulate diffusion of oxygen concentration in the reactor. By the analysis of a natural circulation medium-scale reactor, we make clear that the ON-OFF control and PID control can well control oxygen concentration by choosing an appropriate concentration measurement point. In addition, even when a trouble occurs in the oxygen emission or hydrogen emission system, it observes that control characteristic drops away. It is still possible, however, to control oxygen concentration in such case. (author)

  5. Comparative analysis of QSAR models for predicting pK(a) of organic oxygen acids and nitrogen bases from molecular structure.

    Science.gov (United States)

    Yu, Haiying; Kühne, Ralph; Ebert, Ralf-Uwe; Schüürmann, Gerrit

    2010-11-22

    For 1143 organic compounds comprising 580 oxygen acids and 563 nitrogen bases that cover more than 17 orders of experimental pK(a) (from -5.00 to 12.23), the pK(a) prediction performances of ACD, SPARC, and two calibrations of a semiempirical quantum chemical (QC) AM1 approach have been analyzed. The overall root-mean-square errors (rms) for the acids are 0.41, 0.58 (0.42 without ortho-substituted phenols with intramolecular H-bonding), and 0.55 and for the bases are 0.65, 0.70, 1.17, and 1.27 for ACD, SPARC, and both QC methods, respectively. Method-specific performances are discussed in detail for six acid subsets (phenols and aromatic and aliphatic carboxylic acids with different substitution patterns) and nine base subsets (anilines, primary, secondary and tertiary amines, meta/para-substituted and ortho-substituted pyridines, pyrimidines, imidazoles, and quinolines). The results demonstrate an overall better performance for acids than for bases but also a substantial variation across subsets. For the overall best-performing ACD, rms ranges from 0.12 to 1.11 and 0.40 to 1.21 pK(a) units for the acid and base subsets, respectively. With regard to the squared correlation coefficient r², the results are 0.86 to 0.96 (acids) and 0.79 to 0.95 (bases) for ACD, 0.77 to 0.95 (acids) and 0.85 to 0.97 (bases) for SPARC, and 0.64 to 0.87 (acids) and 0.43 to 0.83 (bases) for the QC methods, respectively. Attention is paid to structural and method-specific causes for observed pitfalls. The significant subset dependence of the prediction performances suggests a consensus modeling approach.

  6. Effect of oxygen enrichment in air on acid gas combustion under Claus conditions

    KAUST Repository

    Ibrahim, Salisu

    2013-09-01

    Results are presented to examine the combustion of acid gas (H2S and CO2) in hydrogen-fueled flames using a mixture of oxygen and nitrogen under Claus conditions (Φ = 3). Specifically the effect of oxygen enrichment in the above flames is examined. The compositions of acid gas examined are100% H2S and 50% H2S/50% CO2 with different percentages of oxygen enrichment (0%, 19.3% and 69.3%) in the oxygen/nitrogen mixtures. The results revealed that combustion of acid gas formed SO2 wherein the mole fraction of SO2 increased to an asymptotic value at all the oxygen concentrations examined. In addition, increase in oxygen enrichment of the air resulted in increased amounts of SO2 rather than the formation of more desirable elemental sulfur. In case of 50% H2S/50% CO2 acid gas, carbon monoxide mole fraction increased with oxygen enrichment which is an indicator to the availability of additional amounts of oxygen into the reaction pool. This gas mixture resulted in the formation of other sulfurous–carbonaceous compounds (COS and CS2) due to the presence of carbon monoxide. The results showed that the rate of COS formation increased with oxygen enrichment due to the availability of higher amounts of CO while that of CS2 reduced. The global reactions responsible for this observed phenomenon are presented.

  7. [Domiciliary oxygen therapy].

    Science.gov (United States)

    Abdel Kafi, S

    2010-09-01

    In Belgium, oxygen therapy is becoming more and more accessible. When oxygen is needed for short periods or for special indications as palliative care, an agreement between mutual insurance companies and pharmacists allows the practitioner the home installation of gazeous oxygen cylinder or of oxygen concentrator. When long term oxygen therapy (LTOT) is indicated for patients with respiratory insufficiency, the pneumologist must first ask the INAMI the authorization to install one of the following modalities: oxygen concentrator with or without demand oxygen delivery cylinder and liquid oxygen. The goal of LTOT is to increase survival and quality of life. The principal and well accepted indication for LTOT is severe hypoxemia. The beneficial effects of oxygen therapy limited at night or on exertion are controversial. In order to increase patient's autonomy, oxygen can be prescribed for ambulation, respecting prescription's rules. At each step of oxygen therapy implementing (indication, choice of the device and follow-up) the patient under oxygen may benefit from a joint approach between the general practitioner and the chest specialist.

  8. Oxygen free radicals in rheumatoid arthritis

    NARCIS (Netherlands)

    P. Biemond (Pieter)

    1986-01-01

    textabstractCurrent knowledge strongly suggests that oxygen free radicals are involved in the pathogenesis of RA. Additional information about the mechanism of free radical attack is necessary in order to find out if interaction with the mechanism of free radical damage can be used in the treatment

  9. Human Innate Lymphoid Cell Subsets Possess Tissue-Type Based Heterogeneity in Phenotype and Frequency

    DEFF Research Database (Denmark)

    Simoni, Yannick; Fehlings, Michael; Kloverpris, Henrik N.

    2017-01-01

    Animal models have highlighted the importance of innate lymphoid cells (ILCs) in multiple immune responses. However, technical limitations have hampered adequate characterization of ILCs in humans. Here, we used mass cytometry including a broad range of surface markers and transcription factors...... to accurately identify and profile ILCs across healthy and inflamed tissue types. High dimensional analysis allowed for clear phenotypic delineation of ILC2 and ILC3 subsets. We were not able to detect ILC1 cells in any of the tissues assessed, however, we identified intra-epithelial (ie)ILC1-like cells...... that represent a broader category of NK cells in mucosal and non-mucosal pathological tissues. In addition, we have revealed the expression of phenotypic molecules that have not been previously described for ILCs. Our analysis shows that human ILCs are highly heterogeneous cell types between individuals...

  10. Oxygen therapy - infants

    Science.gov (United States)

    ... breathe increased amounts of oxygen to get normal levels of oxygen in their blood. Oxygen therapy provides babies with the extra oxygen. Information Oxygen is a gas that the cells in your body need to work properly. The ...

  11. Transposed-Letter Priming Effects with Masked Subset Primes: A Re-Examination of the "Relative Position Priming Constraint"

    Science.gov (United States)

    Stinchcombe, Eric J.; Lupker, Stephen J.; Davis, Colin J.

    2012-01-01

    Three experiments are reported investigating the role of letter order in orthographic subset priming (e.g., "grdn"-GARDEN) using both the conventional masked priming technique as well as the sandwich priming technique in a lexical decision task. In all three experiments, subset primes produced priming with the effect being considerably…

  12. Abortive lytic Epstein–Barr virus replication in tonsil-B lymphocytes in infectious mononucleosis and a subset of the chronic fatigue syndrome

    Directory of Open Access Journals (Sweden)

    Lerner AM

    2012-11-01

    Full Text Available A Martin Lerner,1 Safedin Beqaj21Department of Medicine, Oakland University William Beaumont School of Medicine, Rochester, MI, USA; 2Pathology Inc, Torrance, CA, USAAbstract: A systematic 2001–2007 review of 142 chronic fatigue syndrome (CFS patients identified 106 CFS patients with elevated serum IgG antibodies to the herpesviruses Epstein–Barr virus (EBV, cytomegalovirus, or human herpesvirus (HHV 6 in single or multiple infections, with no other co-infections detected. We named these 106 patients group-A CFS. Eighty-six of these 106 group-A CFS patients (81% had elevated EBV early antibody, early antigen (diffuse, serum titers. A small group of six patients in the group-A EBV subset of CFS, additionally, had repetitive elevated-serum titers of antibody to the early lytic replication-encoded proteins, EBV dUTPase, and EBV DNA polymerase. The presence of these serum antibodies to EBV dUTPase and EBV DNA polymerase indicated EBV abortive lytic replication in these 6 CFS patients. None of 20 random control people (age- and sex-matched, with blood drawn at a commercial laboratory had elevated serum titers of antibody to EBV dUTPase or EBV DNA polymerase (P < 0.01. This finding needs verification in a larger group of EBV CFS subset patients, but if corroborated, it may represent a molecular marker for diagnosing the EBV subset of CFS. We review evidence that EBV abortive lytic replication with unassembled viral proteins in the blood may be the same in infectious mononucleosis (IM and a subset of CFS. EBV-abortive lytic replication in tonsil plasma cells is dominant in IM. No complete lytic virion is in the blood of IM or CFS patients. Complications of CFS and IM include cardiomyopathy and encephalopathy. Circulating abortive lytic-encoded EBV proteins (eg, EBV dUTPase, EBV DNA polymerase, and others may be common to IM and CFS. The intensity and duration of the circulating EBV-encoded proteins might differentiate the IM and EBV subsets of CFS

  13. Oxygen abundance in metal-poor dwarfs, derived from the forbidden line

    Science.gov (United States)

    Spite, M.; Spite, F.

    1991-12-01

    The oxygen abundance is redetermined in a few metal-poor dwarfs, using the oxygen forbidden line at 630 nm rather than the oxygen triplet at 777 nm previously used by Abia and Rebolo (1989). The ratios form O/Fe are clearly lower than the previous ones and are in agreement with the ratios found in the metal-poor red giants, suggesting that no real difference exists between dwarfs and giants. Finally, it can be argued that, pending the acquisition of additional information, the oxygen abundances derived from the forbidden line are more reliable than the abundances found from the triplet.

  14. Improving the characterization of endothelial progenitor cell subsets by an optimized FACS protocol.

    Directory of Open Access Journals (Sweden)

    Karin Huizer

    Full Text Available The characterization of circulating endothelial progenitor cells (EPCs is fundamental to any study related to angiogenesis. Unfortunately, current literature lacks consistency in the definition of EPC subsets due to variations in isolation strategies and inconsistencies in the use of lineage markers. Here we address critical points in the identification of hematopoietic progenitor cells (HPCs, circulating endothelial cells (CECs, and culture-generated outgrowth endothelial cells (OECs from blood samples of healthy adults (AB and umbilical cord (UCB. Peripheral blood mononuclear cells (PBMCs were enriched using a Ficoll-based gradient followed by an optimized staining and gating strategy to enrich for the target cells. Sorted EPC populations were subjected to RT-PCR for tracing the expression of markers beyond the limits of cell surface-based immunophenotyping. Using CD34, CD133 and c-kit staining, combined with FSC and SSC, we succeeded in the accurate and reproducible identification of four HPC subgroups and found significant differences in the respective populations in AB vs. UCB. Co-expression analysis of endothelial markers on HPCs revealed a complex pattern characterized by various subpopulations. CECs were identified by using CD34, KDR, CD45, and additional endothelial markers, and were subdivided according to their apoptotic state and expression of c-kit. Comparison of UCB-CECs vs. AB-CECs revealed significant differences in CD34 and KDR levels. OECs were grown from PBMC-fractions We found that viable c-kit+ CECs are a candidate circulating precursor for CECs. RT-PCR to angiogenic factors and receptors revealed that all EPC subsets expressed angiogenesis-related molecules. Taken together, the improvements in immunophenotyping and gating strategies resulted in accurate identification and comparison of better defined cell populations in a single procedure.

  15. SPECIFICITIES OF THE SUBSET PROFILE OF PERIPHERAL BLOOD IN PATIENTS WITH GLIOBLASTOMA: PATHOGENETIC AND CLINICAL ASSESSMENTS

    Directory of Open Access Journals (Sweden)

    V. A. Chumakov

    2006-01-01

    Full Text Available Abstract. In glioblastoma (GB, it is necessary to take into consideration GB-associated secondary immunodeficiency (SID, so-called syndrome of tumor-associated SID (STASID. Cell subsets having effector and regulatory functions, play an important role in developing STASID, and their proportions in patients with different forms of GB can be of pathogenetic importance and have clinical value for treatment and rehabilitation scheduling as well. The most pathogenically and clinically important features of cell subsets profile of peripheral blood were analyzed in patients with different clinical and morphological types of GB. The patients were divided into three groups, i.e., groups I and II were formed by patients with STASID (marked and slightly marked SID, accordingly; group III – patients with SIDTAS (tumor-associated autoimmune syndrome, associated with SID. Marked suppression of cell immunity is typical of group I - imbalance in T-lymphocytes, in a number of specific subsets, and in subsets clusters, as well as disproportions in the immunoregulatory indexes. In group II, the subset profiles of blood were slightly different from the norm. In patients with SIDTAS, activation of cell immunity was evident, forming SID with signs of autoimmune syndrome, affecting effector and regulatory chains of immunity, and influencing the severity and forecast of the disease. Specific features of the immune status in patients with GB identified can be resulted from different clinicalmorphological types of the tumor; the latter are to be considered in differential diagnostics of clinical course of GB and in scheduling of clinical-immunological efficient anti-tumor pharmacotherapy in pre- and postoperative periods.

  16. Application of subset simulation methods to dynamic fault tree analysis

    International Nuclear Information System (INIS)

    Liu Mengyun; Liu Jingquan; She Ding

    2015-01-01

    Although fault tree analysis has been implemented in the nuclear safety field over the past few decades, it was recently criticized for the inability to model the time-dependent behaviors. Several methods are proposed to overcome this disadvantage, and dynamic fault tree (DFT) has become one of the research highlights. By introducing additional dynamic gates, DFT is able to describe the dynamic behaviors like the replacement of spare components or the priority of failure events. Using Monte Carlo simulation (MCS) approach to solve DFT has obtained rising attention, because it can model the authentic behaviors of systems and avoid the limitations in the analytical method. In this paper, it provides an overview and MCS information for DFT analysis, including the sampling of basic events and the propagation rule for logic gates. When calculating rare-event probability, large amount of simulations in standard MCS are required. To improve the weakness, subset simulation (SS) approach is applied. Using the concept of conditional probability and Markov Chain Monte Carlo (MCMC) technique, the SS method is able to accelerate the efficiency of exploring the failure region. Two cases are tested to illustrate the performance of SS approach, and the numerical results suggest that it gives high efficiency when calculating complicated systems with small failure probabilities. (author)

  17. T lymphocyte subsets in prostate cancer subjects in south eastern ...

    African Journals Online (AJOL)

    Humoral and cellular mechanisms play roles in immune response to foreign antigens. The present study was designed to determine the T lymphocyte subsets (CD4 + T cells, CD8 + T cells and CD4/CD8 ratio) in the prostate cancer subjects and control subjects. CD4 + T cells (`l/count) and CD8 + T cells (`l/count) were ...

  18. Oxygen enriched combustion system performance study. Phase 2: 100 percent oxygen enriched combustion in regenerative glass melters, Final report

    Energy Technology Data Exchange (ETDEWEB)

    Tuson, G.B.; Kobayashi, H.; Campbell, M.J.

    1994-08-01

    The field test project described in this report was conducted to evaluate the energy and environmental performance of 100% oxygen enriched combustion (100% OEC) in regenerative glass melters. Additional objectives were to determine other impacts of 100% OEC on melter operation and glass quality, and to verify on a commercial scale that an on-site Pressure Swing Adsorption oxygen plant can reliably supply oxygen for glass melting with low electrical power consumption. The tests constituted Phase 2 of a cooperative project between the United States Department of Energy, and Praxair, Inc. Phase 1 of the project involved market and technical feasibility assessments of oxygen enriched combustion for a range of high temperature industrial heating applications. An assessment of oxygen supply options for these applications was also performed during Phase 1, which included performance evaluation of a pilot scale 1 ton per day PSA oxygen plant. Two regenerative container glass melters were converted to 100% OEC operation and served as host sites for Phase 2. A 75 ton per day end-fired melter at Carr-Lowrey Glass Company in Baltimore, Maryland, was temporarily converted to 100% OEC in mid- 1990. A 350 tpd cross-fired melter at Gallo Glass Company in Modesto, California was rebuilt for permanent commercial operation with 100% OEC in mid-1991. Initially, both of these melters were supplied with oxygen from liquid storage. Subsequently, in late 1992, a Pressure Swing Adsorption oxygen plant was installed at Gallo to supply oxygen for 100% OEC glass melting. The particular PSA plant design used at Gallo achieves maximum efficiency by cycling the adsorbent beds between pressurized and evacuated states, and is therefore referred to as a Vacuum/Pressure Swing Adsorption (VPSA) plant.

  19. Anoxygenic Photosynthesis Controls Oxygenic Photosynthesis in a Cyanobacterium from a Sulfidic Spring

    KAUST Repository

    Klatt, Judith M.; Alnajjar, Mohammad Ahmad; Yilmaz, Pelin; Lavik, Gaute; de Beer, Dirk; Polerecky, Lubos

    2015-01-01

    Before the Earth's complete oxygenation (0.58 to 0.55 billion years [Ga] ago), the photic zone of the Proterozoic oceans was probably redox stratified, with a slightly aerobic, nutrient-limited upper layer above a light-limited layer that tended toward euxinia. In such oceans, cyanobacteria capable of both oxygenic and sulfide-driven anoxygenic photosynthesis played a fundamental role in the global carbon, oxygen, and sulfur cycle. We have isolated a cyanobacterium, Pseudanabaena strain FS39, in which this versatility is still conserved, and we show that the transition between the two photosynthetic modes follows a surprisingly simple kinetic regulation controlled by this organism's affinity for H2S. Specifically, oxygenic photosynthesis is performed in addition to anoxygenic photosynthesis only when H2S becomes limiting and its concentration decreases below a threshold that increases predictably with the available ambient light. The carbon-based growth rates during oxygenic and anoxygenic photosynthesis were similar. However, Pseudanabaena FS39 additionally assimilated NO3 - during anoxygenic photosynthesis. Thus, the transition between anoxygenic and oxygenic photosynthesis was accompanied by a shift of the C/N ratio of the total bulk biomass. These mechanisms offer new insights into the way in which, despite nutrient limitation in the oxic photic zone in the mid-Proterozoic oceans, versatile cyanobacteria might have promoted oxygenic photosynthesis and total primary productivity, a key step that enabled the complete oxygenation of our planet and the subsequent diversification of life.

  20. Anoxygenic Photosynthesis Controls Oxygenic Photosynthesis in a Cyanobacterium from a Sulfidic Spring

    KAUST Repository

    Klatt, Judith M.

    2015-03-15

    Before the Earth\\'s complete oxygenation (0.58 to 0.55 billion years [Ga] ago), the photic zone of the Proterozoic oceans was probably redox stratified, with a slightly aerobic, nutrient-limited upper layer above a light-limited layer that tended toward euxinia. In such oceans, cyanobacteria capable of both oxygenic and sulfide-driven anoxygenic photosynthesis played a fundamental role in the global carbon, oxygen, and sulfur cycle. We have isolated a cyanobacterium, Pseudanabaena strain FS39, in which this versatility is still conserved, and we show that the transition between the two photosynthetic modes follows a surprisingly simple kinetic regulation controlled by this organism\\'s affinity for H2S. Specifically, oxygenic photosynthesis is performed in addition to anoxygenic photosynthesis only when H2S becomes limiting and its concentration decreases below a threshold that increases predictably with the available ambient light. The carbon-based growth rates during oxygenic and anoxygenic photosynthesis were similar. However, Pseudanabaena FS39 additionally assimilated NO3 - during anoxygenic photosynthesis. Thus, the transition between anoxygenic and oxygenic photosynthesis was accompanied by a shift of the C/N ratio of the total bulk biomass. These mechanisms offer new insights into the way in which, despite nutrient limitation in the oxic photic zone in the mid-Proterozoic oceans, versatile cyanobacteria might have promoted oxygenic photosynthesis and total primary productivity, a key step that enabled the complete oxygenation of our planet and the subsequent diversification of life.

  1. NOx emissions from high swirl turbulent spray flames with highly oxygenated fuels

    KAUST Repository

    Bohon, Myles; Roberts, William L.

    2013-01-01

    Combustion of fuels with fuel bound oxygen is of interest from both a practical and a fundamental viewpoint. While a great deal of work has been done studying the effect of oxygenated additives in diesel and gasoline engines, much less has been done

  2. Oxygen diffusion and oxygen effect in tumor tissue

    International Nuclear Information System (INIS)

    Eissa, H.M.; Hehn, G.

    1979-06-01

    The diffusion of oxygen in tumor cords of bronchus carcinoma of the lung have been studied with refined computer methods for solving the diffusion equation in axis symmetric tumor structures. In this tumor configuration we may find three different regions consisting of euoxic cells, hypoxic tumor cells and necrotic parts. In the case of oxygen supply from a capillary inside a cylinder of tumor tissue with radius 200 μm or in a tumor cord of radius 300 μm with oxygen supply by capillaries outside, we get a relation of well oxygenated cells to hypoxic cells approximately as 1:8 or as 1:1.1 respectively. Of course most of the tumor cords observed in histological slices have smaller diameters, so that an average of approximately 20% hypoxic cells can be assumed. Based on the work of Ardenne, the diffusion of oxygen and glucose in a tumor of type DS-carcinosarcom has been investigated in both intact tumor and tumor treated with ionizing radiation. We can show that a strong reoxygenation effect takes place in that the well supplied regions may increase in some tumor configurations up to a factor of four by volume. The biological consequences of the oxygen pressure determined in tumor cells are discussed in detail. The investigation of oxygen diffusion in the intercapillary tumor region should give a quantitative physical basis for considering the oxygen effect with the aim to explain the advantages of neutron therapy against conventional radiotherapy. (orig./MG) [de

  3. Testing over-representation of observations in subsets of a DEA technology

    DEFF Research Database (Denmark)

    Asmild, Mette; Hougaard, Jens Leth; Olesen, Ole Bent

    2013-01-01

    This paper proposes a test for whether data are over-represented in a given production zone, i.e. a subset of a production possibility set which has been estimated using the non-parametric Data Envelopment Analysis (DEA) approach. A binomial test is used that relates the number of observations...

  4. An efficient algorithm to compute subsets of points in ℤ n

    OpenAIRE

    Pacheco Martínez, Ana María; Real Jurado, Pedro

    2012-01-01

    In this paper we show a more efficient algorithm than that in [8] to compute subsets of points non-congruent by isometries. This algorithm can be used to reconstruct the object from the digital image. Both algorithms are compared, highlighting the improvements obtained in terms of CPU time.

  5. Comparison of the OxyMask and Venturi mask in the delivery of supplemental oxygen: Pilot study in oxygen-dependent patients

    Science.gov (United States)

    Beecroft, Jaime M; Hanly, Patrick J

    2006-01-01

    BACKGROUND: The OxyMask (Southmedic Inc, Canada) is a new face mask for oxygen delivery that uses a small ‘diffuser’ to concentrate and direct oxygen toward the mouth and nose. The authors hypothesized that this unique design would enable the OxyMask to deliver oxygen more efficiently than a Venturi mask (Hudson RCI, USA) in patients with chronic hypoxemia. METHODS: Oxygen-dependent patients with chronic, stable respiratory disease were recruited to compare the OxyMask and Venturi mask in a randomized, single-blind, cross-over design. Baseline blood oxygen saturation (SaO2) was established breathing room air, followed in a random order by supplemental oxygen through the OxyMask or Venturi mask. Oxygen delivery was titrated to maintain SaO2 4% to 5% and 8% to 9% above baseline for two separate 30 min periods of stable breathing. Oxygen flow rate, partial pressure of inspired and expired oxygen (PO2) and carbon dioxide (PCO2), minute ventilation, heart rate, nasal and oral breathing, SaO2 and transcutaneous PCO2 were collected continuously. The study was repeated following alterations to the OxyMask design, which improved clearance of carbon dioxide. RESULTS: Thirteen patients, aged 28 to 79 years, were studied initially using the original OxyMask. Oxygen flow rate was lower, inspired PO2 was higher and expired PO2 was lower while using the OxyMask. Minute ventilation and inspired and expired PCO2 were significantly higher while using the OxyMask, whereas transcutaneous PCO2, heart rate and the ratio of nasal to oral breathing did not change significantly throughout the study. Following modification of the OxyMask, 13 additional patients, aged 18 to 79 years, were studied using the same protocol. The modified OxyMask provided a higher inspired PO2 at a lower flow rate, without evidence of carbon dioxide retention. CONCLUSIONS: Oxygen is delivered safely and more efficiently by the OxyMask than by the Venturi mask in stable oxygen-dependent patients. PMID:16896425

  6. Comparison of subset-based local and FE-based global digital image correlation: Theoretical error analysis and validation

    KAUST Repository

    Pan, B.

    2016-03-22

    Subset-based local and finite-element-based (FE-based) global digital image correlation (DIC) approaches are the two primary image matching algorithms widely used for full-field displacement mapping. Very recently, the performances of these different DIC approaches have been experimentally investigated using numerical and real-world experimental tests. The results have shown that in typical cases, where the subset (element) size is no less than a few pixels and the local deformation within a subset (element) can be well approximated by the adopted shape functions, the subset-based local DIC outperforms FE-based global DIC approaches because the former provides slightly smaller root-mean-square errors and offers much higher computation efficiency. Here we investigate the theoretical origin and lay a solid theoretical basis for the previous comparison. We assume that systematic errors due to imperfect intensity interpolation and undermatched shape functions are negligibly small, and perform a theoretical analysis of the random errors or standard deviation (SD) errors in the displacements measured by two local DIC approaches (i.e., a subset-based local DIC and an element-based local DIC) and two FE-based global DIC approaches (i.e., Q4-DIC and Q8-DIC). The equations that govern the random errors in the displacements measured by these local and global DIC approaches are theoretically derived. The correctness of the theoretically predicted SD errors is validated through numerical translation tests under various noise levels. We demonstrate that the SD errors induced by the Q4-element-based local DIC, the global Q4-DIC and the global Q8-DIC are 4, 1.8-2.2 and 1.2-1.6 times greater, respectively, than that associated with the subset-based local DIC, which is consistent with our conclusions from previous work. © 2016 Elsevier Ltd. All rights reserved.

  7. Identification of the Gene for Scleroderma in the Tsk/2 Mouse Strain: Implications for Human Scleroderma Pathogenesis and subset Distinctions

    Science.gov (United States)

    2014-07-01

    in) the) fibroproliferative) subset) and) Tsk2/+) mice) we) analyzed) the) expression)of)the)TGFβFregulated)gene) tumor )necrosis)factor)receptor... esophagus , and gastrointestinal tract (LeRoy et al., 1988). Survival rates vary significantly between and within subsets of disease, and are usually...patients in the fibroproliferative subset and Tsk2/+ mice we analyzed the expression of the TGFβ- regulated gene tumor necrosis factor receptor superfamily

  8. Monitoring bioremediation of weathered diesel NAPL using oxygen depletion profiles

    International Nuclear Information System (INIS)

    Davis, G.B.; Johnston, C.D.; Patterson, B.M.; Barber, C.; Bennett, M.

    1995-01-01

    Semicontinuous logging of oxygen concentrations at multiple depths has been used to evaluate the progress of an in situ bioremediation trial at a site contaminated by weathered diesel nonaqueous-phase liquid (NAPL). The evaluation trial consisted of periodic addition of nutrients and aeration of a 100-m 2 trial plot. During the bioremediation trial, aeration was stopped periodically, and decreases in dissolved and gaseous oxygen concentrations were monitored using data loggers attached to in situ oxygen sensors placed at multiple depths above and within a thin NAPL-contaminated zone. Oxygen usage rate coefficients were determined by fitting zero- and first-order rate equations to the oxygen depletion curves. For nutrient-amended sites within the trial plot, estimates of oxygen usage rate coefficients were significantly higher than estimates from unamended sites. These rates also converted to NPL degradation rates, comparable to those achieved in previous studies, despite the high concentrations and weathered state of the NAPL at this test site

  9. CD45RC isoform expression identifies functionally distinct T cell subsets differentially distributed between healthy individuals and AAV patients.

    Directory of Open Access Journals (Sweden)

    Laurence Ordonez

    Full Text Available In animal models of anti-neutrophil cytoplasmic antibody (ANCA-associated vasculitis (AAV, the proportion of CD45RC T cell subsets is important for disease susceptibility. Their human counterparts are, however, functionally ill defined. In this report, we studied their distribution in healthy controls (HC, AAV patients and in Systemic lupus erythematous (SLE patients as disease controls. We showed that CD45RC expression level on human CD4 and CD8 T cells identifies subsets that are highly variable among individuals. Interestingly, AAV patients exhibit an increased proportion of CD45RC(low CD4 T cells as compared to HC and SLE patients. This increase is stable over time and independent of AAV subtype, ANCA specificity, disease duration, or number of relapses. We also analyzed the cytokine profile of purified CD4 and CD8 CD45RC T cell subsets from HC, after stimulation with anti-CD3 and anti-CD28 mAbs. The CD45RC subsets exhibit different cytokine profiles. Type-1 cytokines (IL-2, IFN-gamma and TNF-alpha were produced by all CD45RC T cell subsets, while the production of IL-17, type-2 (IL-4, IL-5 and regulatory (IL-10 cytokines was restricted to the CD45RC(low subset. In conclusion, we have shown that CD45RC expression divides human T cells in functionally distinct subsets that are imbalanced in AAV. Since this imbalance is stable over time and independent of several disease parameters, we hypothesize that this is a pre-existing immune abnormality involved in the etiology of AAV.

  10. Crossing the Vascular Wall: Common and Unique Mechanisms Exploited by Different Leukocyte Subsets during Extravasation

    Directory of Open Access Journals (Sweden)

    Michael Schnoor

    2015-01-01

    Full Text Available Leukocyte extravasation is one of the essential and first steps during the initiation of inflammation. Therefore, a better understanding of the key molecules that regulate this process may help to develop novel therapeutics for treatment of inflammation-based diseases such as atherosclerosis or rheumatoid arthritis. The endothelial adhesion molecules ICAM-1 and VCAM-1 are known as the central mediators of leukocyte adhesion to and transmigration across the endothelium. Engagement of these molecules by their leukocyte integrin receptors initiates the activation of several signaling pathways within both leukocytes and endothelium. Several of such events have been described to occur during transendothelial migration of all leukocyte subsets, whereas other mechanisms are known only for a single leukocyte subset. Here, we summarize current knowledge on regulatory mechanisms of leukocyte extravasation from a leukocyte and endothelial point of view, respectively. Specifically, we will focus on highlighting common and unique mechanisms that specific leukocyte subsets exploit to succeed in crossing endothelial monolayers.

  11. Quadruple labelled dual oxygen and pH-sensitive ratiometric nanosensors

    Directory of Open Access Journals (Sweden)

    Veeren M. Chauhan

    2016-05-01

    Full Text Available Nanosensors capable of simultaneously measuring dissolved oxygen concentrations from 0 to 100% saturation and pH over the full physiological range, from pH 3.5 to 7.5, that advance the methods towards understanding of key biological gradients, were synthesised. A library of water soluble oxygen-sensitive porphyrins, with three substituted charged functional groups and a chemically flexible carboxylate functional group were spectroscopically analysed to assess their sensitivity to changes in dissolved oxygen concentrations as free species in solution and in suspension as nanoparticle conjugates. A platinum cationic porphyrin was taken forward to fabricate ratiometric oxygen-sensitive nanosensors, using 5-(and-6-carboxytetramethylrhodamine (TAMRA as internal standard. In addition, quadruple labelled dual oxygen and pH-sensitive nanosensors were synthesised using the cationic Pt porphyrin, pH-sensitive fluorescein dyes, carboxyfluorescein (FAM and Oregon Green (OG, in a 1:1 ratio, and TAMRA. We envisage the dual oxygen and pH nanosensors will find broad utility in the characterisation of diverse microenvironments, where there are complex interactions between molecular oxygen and pH. Keywords: Fluorescent, Phosphorescent, Nanosensor, Oxygen, pH, Ratiometric, Platinum metalloporphyrin

  12. Nonvolatile memory effect of tungsten nanocrystals under oxygen plasma treatments

    International Nuclear Information System (INIS)

    Chen, Shih-Cheng; Chang, Ting-Chang; Chen, Wei-Ren; Lo, Yuan-Chun; Wu, Kai-Ting; Sze, S.M.; Chen, Jason; Liao, I.H.; Yeh, Fon-Shan

    2010-01-01

    In this work, an oxygen plasma treatment was used to improve the memory effect of nonvolatile W nanocrystal memory, including memory window, retention and endurance. To investigate the role of the oxygen plasma treatment in charge storage characteristics, the X-ray photon-emission spectra (XPS) were performed to analyze the variation of chemical composition for W nanocrystal embedded oxide both with and without the oxygen plasma treatment. In addition, the transmission electron microscopy (TEM) analyses were also used to identify the microstructure in the thin film and the size and density of W nanocrystals. The device with the oxygen plasma treatment shows a significant improvement of charge storage effect, because the oxygen plasma treatment enhanced the quality of silicon oxide surrounding the W nanocrystals. Therefore, the data retention and endurance characteristics were also improved by the passivation.

  13. Monitoring and measurement of oxygen concentrations in liquid sodium

    International Nuclear Information System (INIS)

    Smith, D.L.

    1976-01-01

    The measurement of oxygen concentrations in sodium at levels of interest for LMFBR applications is reviewed. Additional data are presented to support the validity of the vanadium-equilibration method as a reference for determination of oxygen concentrations in sodium at levels equal to or less than 15 ppM. Operating experience with electrochemical oxygen meters that have a thoria-yttria electrolyte and a Na--Na 2 O reference electrode is described. Meter lifetimes in excess of one year have generally been achieved for operating temperatures of 352 and 402 0 C, and fairly stable emfs have been observed for periods of several months. 7 fig, 21 references

  14. Endothelial progenitor cell subsets and preeclampsia: Findings and controversies

    Directory of Open Access Journals (Sweden)

    Armin Attar

    2017-10-01

    Full Text Available Vascular remodeling is an essential component of gestation. Endothelial progenitor cells (EPCs play an important role in the regulation of vascular homeostasis. The results of studies measuring the number of EPCs in normal pregnancies and in preeclampsia have been highly controversial or even contradictory because of some variations in technical issues and different methodologies enumerating three distinct subsets of EPCs: circulating angiogenic cells (CAC, colony forming unit endothelial cells (CFU-ECs, and endothelial colony-forming cells (ECFCs. In general, most studies have shown an increase in the number of CACs in the maternal circulation with a progression in the gestational age in normal pregnancies, while functional capacities measured by CFU-ECs and ECFCs remain intact. In the case of preeclampsia, mobilization of CACs and ECFCs occurs in the peripheral blood of pregnant women, but the functional capacities shown by culture of the derived colony-forming assays (CFU-EC and ECFC assays are altered. Furthermore, the number of all EPC subsets will be reduced in umbilical cord blood in the case of preeclampsia. As EPCs play an important role in the homeostasis of vascular networks, the difference in their frequency and functionality in normal pregnancies and those with preeclampsia can be expected. In this review, there was an attempt to provide a justification for these controversies.

  15. Characterization of Peripheral Immune Cell Subsets in Patients with Acute and Chronic Cerebrovascular Disease: A Case-Control Study

    Directory of Open Access Journals (Sweden)

    Peter Kraft

    2015-10-01

    Full Text Available Immune cells (IC play a crucial role in murine stroke pathophysiology. However, data are limited on the role of these cells in ischemic stroke in humans. We therefore aimed to characterize and compare peripheral IC subsets in patients with acute ischemic stroke/transient ischemic attack (AIS/TIA, chronic cerebrovascular disease (CCD and healthy volunteers (HV. We conducted a case-control study of patients with AIS/TIA (n = 116 or CCD (n = 117, and HV (n = 104 who were enrolled at the University Hospital Würzburg from 2010 to 2013. We determined the expression and quantity of IC subsets in the three study groups and performed correlation analyses with demographic and clinical parameters. The quantity of several IC subsets differed between the AIS/TIA, CCD, and HV groups. Several clinical and demographic variables independently predicted the quantity of IC subsets in patients with AIS/TIA. No significant changes in the quantity of IC subsets occurred within the first three days after AIS/TIA. Overall, these findings strengthen the evidence for a pathophysiologic role of IC in human ischemic stroke and the potential use of IC-based biomarkers for the prediction of stroke risk. A comprehensive description of IC kinetics is crucial to enable the design of targeted treatment strategies.

  16. Modeling the Effect of the Selective S1P1 Receptor Modulator Ponesimod on Subsets of Blood Lymphocytes.

    Science.gov (United States)

    Lott, Dominik; Krause, Andreas; Seemayer, Christian A; Strasser, Daniel S; Dingemanse, Jasper; Lehr, Thorsten

    2017-03-01

    This analysis aimed at describing the effect of the selective sphingosine-1-phosphate receptor 1 modulator ponesimod on lymphocyte subsets in peripheral blood. As the involvement of different lymphocyte subsets varies among different autoimmune diseases, characterizing the effect of ponesimod on these may be beneficial in better understanding treatment effects. Three phase 1 clinical studies in healthy human subjects were pooled. Non-linear mixed-effects modeling techniques were used to study the effect of ponesimod on lymphocyte subsets such as B cells, T helper cells, T cytotoxic cells, and natural killer cells in a qualitative and quantitative manner. Indirect-response I max models including circadian variation best described the effect of ponesimod on lymphocyte subsets. B cells and T helper cells were shown to be more affected compared to T cytotoxic cells with respect to the maximum possible reduction (100% for B and T helper cells, 95% for T cytotoxic cells) and the concentration required to reach half the maximum effect. Inter-individual variability was found to be larger for T cytotoxic compared to T helper, and B cells. These first models for ponesimod on the level of lymphocyte subsets offer a valuable tool for the analysis and interpretation of results from ponesimod trials in autoimmune diseases.

  17. Oxygen effect and intracellular oxygen content (adaptation hypothesis)

    Energy Technology Data Exchange (ETDEWEB)

    Yarmonenko, S P; Ehpshtejn, I M [Akademiya Meditsinskikh Nauk SSSR, Moscow. Onkologicheskij Tsentr

    1977-01-01

    Experimental data indicating that a radiomodifying action of hypoxia is dependent on the ''prehistory'' of the irradiated object are considered. This dependence manifests itself in a decreased protective action of acute hypoxia on the hypoxia-adapted objects. To explain this a hypothesis is proposed connecting a degree of cell radiosensitivity modification, determined by the oxygen effect, with the intracellular oxygen content. The latter, in accord with current ideas, is regulated by variations in the diffusion resistance to oxygen shown by the cytoplasmic membranes depending on the energy level of the cell and the degree of its oxygenation.

  18. Oxygen effect and intracellular oxygen content (adaptation hypothesis)

    International Nuclear Information System (INIS)

    Yarmonenko, S.P.; Ehpshtejn, I.M.

    1977-01-01

    Experimental data indicating that a radiomodifying action of hypoxia is dependent on the ''prehistory'' of the irradiated object are considered. This dependence manifests itself in a decreased protective action of acute hypoxia on the hypoxia-adapted objects. To explain this a hypothesis is proposed connecting a degree of cell radiosensitivity modification, determined by the oxygen effect, with the intracellular oxygen content. The latter, in accord with current ideas, is regulated by variations in the diffusion resistance to oxygen shown by the cytoplasmic membranes depending on the energy level of the cell and the degree of its oxygenation

  19. Singular Sheet Etching of Graphene with Oxygen Plasma

    Institute of Scientific and Technical Information of China (English)

    Haider Al-Mumen; Fubo Rao; Wen Li; Lixin Dong

    2014-01-01

    This paper reports a simple and controllable post-synthesis method for engineering the number of graphene layers based on oxygen plasma etching. Singular sheet etching(SSE) of graphene was achieved with the optimum process duration of 38 seconds. As a demonstration of this SSE process, monolayer graphene films were produced from bilayer graphenes. Experimental investigations verified that the oxygen plasma etching removes a single layer graphene sheet in an anisotropic fashion rather than anisotropic mode. In addition,etching via the oxygen plasma at the ground electrodes introduced fewer defects to the bottom graphene layer compared with the conventional oxygen reactive ion etching using the powered electrodes. Such defects can further be reduced with an effective annealing treatment in an argon environment at 900-1000?C. These results demonstrate that our developed SSE method has enabled a microelectronics manufacturing compatible way for single sheet precision subtraction of graphene layers and a potential technique for producing large size graphenes with high yield from multilayer graphite materials.

  20. Singular Sheet Etching of Graphene with Oxygen Plasma

    Institute of Scientific and Technical Information of China (English)

    Haider Al-Mumen; Fubo Rao; Wen Li; Lixin Dong

    2014-01-01

    This paper reports a simple and controllable post-synthesis method for engineering the number of graphene layers based on oxygen plasma etching. Singular sheet etching (SSE) of graphene was achieved with the optimum process duration of 38 seconds. As a demonstration of this SSE process, monolayer graphene films were produced from bilayer graphenes. Experimental investigations verified that the oxygen plasma etching removes a single layer graphene sheet in an anisotropic fashion rather than anisotropic mode. In addition, etching via the oxygen plasma at the ground electrodes introduced fewer defects to the bottom graphene layer compared with the conventional oxygen reactive ion etching using the powered electrodes. Such defects can further be reduced with an effective annealing treatment in an argon environment at 900-1000◦C. These results demonstrate that our developed SSE method has enabled a microelectronics manufacturing compatible way for single sheet precision subtraction of graphene layers and a potential technique for producing large size graphenes with high yield from multilayer graphite materials.

  1. Characterization of αβ and γδ T cell subsets expressing IL-17A in ruminants and swine.

    Science.gov (United States)

    Elnaggar, Mahmoud M; Abdellrazeq, Gaber S; Dassanayake, Rohana P; Fry, Lindsay M; Hulubei, Victoria; Davis, William C

    2018-08-01

    As part of our ongoing program to expand immunological reagents available for research in cattle, we developed a monoclonal antibody (mAb) to bovine interleukin-17A (IL-17A), a multifunctional cytokine centrally involved in regulating innate and adaptive immune responses. Initial comparative studies demonstrated the mAb recognizes a conserved epitope expressed on orthologues of IL-17A in sheep, goats and pigs. Comparative flow cytometric analyses of lymphocyte subsets stimulated with phorbol 12-myristate 13-acetate (PMA) and ionomycin revealed differences in expression of IL-17A by CD4, CD8, and γδ T cells across ruminants and swine species. Results in cattle showed the largest proportion of IL-17A + cells were CD4 + followed by γδ and CD8 + T cells. Further analysis revealed the IL-17A + γδ T cell subset was comprised of WC1.1 + , WC1.2 + , and WC1 - subsets. Analysis of the IL-17A + CD8 + T cell subset revealed it was comprised of αβ and γδ T cell subsets. Results in sheep and goats revealed IL-17A is expressed mainly by CD4 + and CD8 + T cells, with little expression by γδ T cells. Analysis of IL-17A + CD8 + T cells showed the majority were CD8 + αβ in sheep, whereas they were CD8 + γδ in goats. The majority of the sheep and goat IL-17A + γδ T cells were WC1 + . Results obtained in swine showed expression of IL-17A by CD4, CD8, and γδ T cell subsets were similar to results reported in other studies. Comparison of expression of IL-17A with IFN-γ revealed subsets co-expressed IL-17A and IFN-γ in cattle, sheep, and goats. The new mAb expands opportunities for immunology research in ruminants and swine. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Behavior of oxygen impurities in tokamak. Vol. 2

    Energy Technology Data Exchange (ETDEWEB)

    El-Sharif, R N; Beket, A H [Plasma and Nuclear Fusion Department, Nuclear Research Center, Atomic Energy Aurhority, Cairo (Egypt)

    1996-03-01

    Impurity transport in tokamak plasma is a subject of great importance in present day tokamak experiments. The transport of oxygen as an impurity element in small tokamak was studied theoretically. The viscosity coefficient of oxygen has been calculated in different approximation 13 and 21 moment approximation, taking into consideration {chi}>>1,{chi}{omega}{sub c} {tau}. It was found that in 21 moment approximation additional terms added to the perturbation from equilibrium leads to increase in viscosity coefficients than in 13 moments approximation. 9 figs.

  3. The role of dendritic cell subsets and innate immunity in the pathogenesis of type 1 diabetes and other autoimmune diseases

    Directory of Open Access Journals (Sweden)

    Jeffrey D. Price

    2015-06-01

    Full Text Available Dendritic cells (DCs are key antigen presenting cells that have an important role in autoimmune pathogenesis. DCs control both steady-state T cell tolerance and activation of pathogenic responses. The balance between these two outcomes depends on several factors, including genetic susceptibility, environmental signals that stimulate varied innate responses, and which DC subset is presenting antigen. Although the specific DC phenotype can diverge depending on the tissue location and context, there are 4 main subsets identified in both mouse and human: conventional cDC1 and cDC2, plasmacytoid DCs, and monocyte-derived DCs. In this review, we will discuss the role of these subsets in autoimmune pathogenesis and regulation, as well as the genetic and environmental signals that influence their function. Specific topics to be addressed include: impact of susceptibility loci on DC subsets, alterations in DC subset development, the role of infection- and host-derived innate inflammatory signals, and the role of the intestinal microbiota on DC phenotype. The effects of these various signals on disease progression and the relative effects of DC subset composition and maturation level of DCs will be examined. These areas will be explored using examples from several autoimmune diseases but will focus mainly on type 1 diabetes.

  4. Oxygen Therapy

    Science.gov (United States)

    ... their breathing to dangerously low levels. Will I need oxygen when I sleep? Usually if you use supplemental oxygen during the ... your health care provider tells you you only need to use oxygen for exercise or sleep. Even if you feel “fine” off of your ...

  5. Single-cell measurement of red blood cell oxygen affinity.

    Science.gov (United States)

    Di Caprio, Giuseppe; Stokes, Chris; Higgins, John M; Schonbrun, Ethan

    2015-08-11

    Oxygen is transported throughout the body by hemoglobin (Hb) in red blood cells (RBCs). Although the oxygen affinity of blood is well-understood and routinely assessed in patients by pulse oximetry, variability at the single-cell level has not been previously measured. In contrast, single-cell measurements of RBC volume and Hb concentration are taken millions of times per day by clinical hematology analyzers, and they are important factors in determining the health of the hematologic system. To better understand the variability and determinants of oxygen affinity on a cellular level, we have developed a system that quantifies the oxygen saturation, cell volume, and Hb concentration for individual RBCs in high throughput. We find that the variability in single-cell saturation peaks at an oxygen partial pressure of 2.9%, which corresponds to the maximum slope of the oxygen-Hb dissociation curve. In addition, single-cell oxygen affinity is positively correlated with Hb concentration but independent of osmolarity, which suggests variation in the Hb to 2,3-diphosphoglycerate (2-3 DPG) ratio on a cellular level. By quantifying the functional behavior of a cellular population, our system adds a dimension to blood cell analysis and other measurements of single-cell variability.

  6. Study of T cell subsets in patients with chronic glomerulonephritis by immuno-labelling technique

    International Nuclear Information System (INIS)

    Dong Jixiang; Zhang Xueguang; Liu Zhida; Han Huiqin; Xie Wei

    1998-12-01

    As the developing of nuclear industry science, the possibility of nuclear radiation has increased rapidly. Treatments of diseases caused by radiation, especially acute radiation injury, rely heavily on bone marrow transplantation. The usage of immunology inhibitors is crucial to successfully carrying out bone marrow transplantation. So it is important to find out and research on immunology inhibitors. Using the changes of T cell subsets as a marker of immunology function before and after treatment of chronic glomerulonephritis, the authors observed the effect of Tripterygium wilfordii (TW)--an Chinese traditional drug which may probably become an important immunology inhibitor--on the treatment of chronic glomerulonephritis. Methods: immuno-labelling technique was used to measure the changes of T cell subsets in 77 CGN patients before and after treated with TW. Results: CD3 + and CD4 + cells in CGN patients were lower than those in healthy control (p + to CD8 + (CD4 + /CD8 + ) cells reduced significantly (p + , CD4 + cells and the ratio of CD4 + /CD8 + in most of the patients with CGN were further reduced. In patients with uremia, only CD3 + cell level was lower than the level before treatment, while the ratio of CD4 + to CD8 + (CD4 + /CD8 + ) did not change markedly. Conclusion: The imbalance of various T cell subsets and dysfunction of these T cells may play an important role in the pathogenesis of CGN. the increase in γδT cells may be related with the development of CGN. The pharmacological mechanism of TW in the treatment of CGN patients may involve regulation of balance of T cell subsets and inhibition of the T helper functions

  7. Retinal Vessel Oxygen Saturation during 100% Oxygen Breathing in Healthy Individuals.

    Directory of Open Access Journals (Sweden)

    Olof Birna Olafsdottir

    Full Text Available To detect how systemic hyperoxia affects oxygen saturation in retinal arterioles and venules in healthy individuals.Retinal vessel oxygen saturation was measured in 30 healthy individuals with a spectrophotometric retinal oximeter (Oxymap T1. Oximetry was performed during breathing of room air, 100% oxygen (10 minutes, 6L/min and then again room air (10 minutes recovery.Mean oxygen saturation rises modestly in retinal arterioles during 100% oxygen breathing (94.5%±3.8 vs. 92.0%±3.7% at baseline, p<0.0001 and dramatically in retinal venules (76.2%±8.0% vs. 51.3%±5.6%, p<0.0001. The arteriovenous difference decreased during 100% oxygen breathing (18.3%±9.0% vs. 40.7%±5.7%, p<0.0001. The mean diameter of arterioles decreased during 100% oxygen breathing compared to baseline (9.7±1.4 pixels vs. 10.3±1.3 pixels, p<0.0001 and the same applies to the mean venular diameter (11.4±1.2 pixels vs. 13.3±1.5 pixels, p<0.0001.Breathing 100% oxygen increases oxygen saturation in retinal arterioles and more so in venules and constricts them compared to baseline levels. The dramatic increase in oxygen saturation in venules reflects oxygen flow from the choroid and the unusual vascular anatomy and oxygen physiology of the eye.

  8. Additive influence of extracellular pH, oxygen tension, and pressure on invasiveness and survival of human osteosarcoma cells

    Directory of Open Access Journals (Sweden)

    Takao eMatsubara

    2013-07-01

    Full Text Available BACKGROUND/PURPOSE:The effects of chemical and physical interactions in the microenvironment of solid tumors have not been fully elucidated. We hypothesized that acidosis, hypoxia, and elevated interstitial fluid pressure (eIFP have additive effects on tumor cell biology and lead to more aggressive behavior during tumor progression. We investigated this phenomenon using 3 human osteosarcoma cell lines and a novel in vitro cell culture apparatus. MATERIALS AND METHODS:U2OS, SaOS, and MG63 cell lines were cultured in media adjusted to various pH levels, oxygen tension (hypoxia 2% O2, normoxia 20% O2, and hydrostatic gauge pressure (0 or 50 mm Hg. Growth rate, apoptosis, cell cycle parameters, and expression of mRNA for proteins associated with invasiveness and tumor microenvironment (CA IX, VEGF-A, HIF-1A, MMP-9, and TIMP-2 were analyzed. Levels of CA IX, HIF-1α, and MMP-9 were measured using immunofluorescence. The effect of pH on invasiveness was evaluated in a Matrigel chamber assay.RESULTS: Within the acidic–hypoxic–pressurized conditions that simulate the microenvironment at a tumor’s center, invasive genes were upregulated, but the cell cycle was downregulated. The combined influence of acidosis, hypoxia, and IFP promoted invasiveness and angiogenesis to a greater extent than did pH, pO2, or eIFP individually. Significant cell death after brief exposure to acidic conditions occurred in each cell line during acclimation to acidic media, while prolonged exposure to acidic media resulted in reduced cell death. Furthermore, 48-hour exposure to acidic conditions promoted tumor invasiveness in the Matrigel assay. CONCLUSION: Our findings demonstrate that tumor microenvironmental parameters—particularly pH, pO2, and eIFP—additively influence tumor proliferation, invasion, metabolism, and viability to enhance cell survival.

  9. Experimentally-derived fibroblast gene signatures identify molecular pathways associated with distinct subsets of systemic sclerosis patients in three independent cohorts.

    Directory of Open Access Journals (Sweden)

    Michael E Johnson

    Full Text Available Genome-wide expression profiling in systemic sclerosis (SSc has identified four 'intrinsic' subsets of disease (fibroproliferative, inflammatory, limited, and normal-like, each of which shows deregulation of distinct signaling pathways; however, the full set of pathways contributing to this differential gene expression has not been fully elucidated. Here we examine experimentally derived gene expression signatures in dermal fibroblasts for thirteen different signaling pathways implicated in SSc pathogenesis. These data show distinct and overlapping sets of genes induced by each pathway, allowing for a better understanding of the molecular relationship between profibrotic and immune signaling networks. Pathway-specific gene signatures were analyzed across a compendium of microarray datasets consisting of skin biopsies from three independent cohorts representing 80 SSc patients, 4 morphea, and 26 controls. IFNα signaling showed a strong association with early disease, while TGFβ signaling spanned the fibroproliferative and inflammatory subsets, was associated with worse MRSS, and was higher in lesional than non-lesional skin. The fibroproliferative subset was most strongly associated with PDGF signaling, while the inflammatory subset demonstrated strong activation of innate immune pathways including TLR signaling upstream of NF-κB. The limited and normal-like subsets did not show associations with fibrotic and inflammatory mediators such as TGFβ and TNFα. The normal-like subset showed high expression of genes associated with lipid signaling, which was absent in the inflammatory and limited subsets. Together, these data suggest a model by which IFNα is involved in early disease pathology, and disease severity is associated with active TGFβ signaling.

  10. Anoxygenic photosynthesis controls oxygenic photosynthesis in a cyanobacterium from a sulfidic spring.

    Science.gov (United States)

    Klatt, Judith M; Al-Najjar, Mohammad A A; Yilmaz, Pelin; Lavik, Gaute; de Beer, Dirk; Polerecky, Lubos

    2015-03-01

    Before the Earth's complete oxygenation (0.58 to 0.55 billion years [Ga] ago), the photic zone of the Proterozoic oceans was probably redox stratified, with a slightly aerobic, nutrient-limited upper layer above a light-limited layer that tended toward euxinia. In such oceans, cyanobacteria capable of both oxygenic and sulfide-driven anoxygenic photosynthesis played a fundamental role in the global carbon, oxygen, and sulfur cycle. We have isolated a cyanobacterium, Pseudanabaena strain FS39, in which this versatility is still conserved, and we show that the transition between the two photosynthetic modes follows a surprisingly simple kinetic regulation controlled by this organism's affinity for H2S. Specifically, oxygenic photosynthesis is performed in addition to anoxygenic photosynthesis only when H2S becomes limiting and its concentration decreases below a threshold that increases predictably with the available ambient light. The carbon-based growth rates during oxygenic and anoxygenic photosynthesis were similar. However, Pseudanabaena FS39 additionally assimilated NO3 (-) during anoxygenic photosynthesis. Thus, the transition between anoxygenic and oxygenic photosynthesis was accompanied by a shift of the C/N ratio of the total bulk biomass. These mechanisms offer new insights into the way in which, despite nutrient limitation in the oxic photic zone in the mid-Proterozoic oceans, versatile cyanobacteria might have promoted oxygenic photosynthesis and total primary productivity, a key step that enabled the complete oxygenation of our planet and the subsequent diversification of life. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  11. Study on the effect of hydrogen addition on the variation of plasma parameters of argon-oxygen magnetron glow discharge for synthesis of TiO2 films

    Directory of Open Access Journals (Sweden)

    Partha Saikia

    2016-04-01

    Full Text Available We report the effect of hydrogen addition on plasma parameters of argon-oxygen magnetron glow discharge plasma in the synthesis of H-doped TiO2 films. The parameters of the hydrogen-added Ar/O2 plasma influence the properties and the structural phases of the deposited TiO2 film. Therefore, the variation of plasma parameters such as electron temperature (Te, electron density (ne, ion density (ni, degree of ionization of Ar and degree of dissociation of H2 as a function of hydrogen content in the discharge is studied. Langmuir probe and Optical emission spectroscopy are used to characterize the plasma. On the basis of the different reactions in the gas phase of the magnetron discharge, the variation of plasma parameters and sputtering rate are explained. It is observed that the electron and heavy ion density decline with gradual addition of hydrogen in the discharge. Hydrogen addition significantly changes the degree of ionization of Ar which influences the structural phases of the TiO2 film.

  12. Maximum parsimony on subsets of taxa.

    Science.gov (United States)

    Fischer, Mareike; Thatte, Bhalchandra D

    2009-09-21

    In this paper we investigate mathematical questions concerning the reliability (reconstruction accuracy) of Fitch's maximum parsimony algorithm for reconstructing the ancestral state given a phylogenetic tree and a character. In particular, we consider the question whether the maximum parsimony method applied to a subset of taxa can reconstruct the ancestral state of the root more accurately than when applied to all taxa, and we give an example showing that this indeed is possible. A surprising feature of our example is that ignoring a taxon closer to the root improves the reliability of the method. On the other hand, in the case of the two-state symmetric substitution model, we answer affirmatively a conjecture of Li, Steel and Zhang which states that under a molecular clock the probability that the state at a single taxon is a correct guess of the ancestral state is a lower bound on the reconstruction accuracy of Fitch's method applied to all taxa.

  13. Inferences about nested subsets structure when not all species are detected

    Science.gov (United States)

    Cam, E.; Nichols, J.D.; Hines, J.E.; Sauer, J.R.

    2000-01-01

    Comparisons of species composition among ecological communities of different size have often provided evidence that the species in communities with lower species richness form nested subsets of the species in larger communities. In the vast majority of studies, the question of nested subsets has been addressed using information on presence-absence, where a '0' is interpreted as the absence of a given species from a given location. Most of the methodological discussion in earlier studies investigating nestedness concerns the approach to generation of model-based matrices. However, it is most likely that in many situations investigators cannot detect all the species present in the location sampled. The possibility that zeros in incidence matrices reflect nondetection rather than absence of species has not been considered in studies addressing nested subsets, even though the position of zeros in these matrices forms the basis of earlier inference methods. These sampling artifacts are likely to lead to erroneous conclusions about both variation over space in species richness and the degree of similarity of the various locations. Here we propose an approach to investigation of nestedness, based on statistical inference methods explicitly incorporating species detection probability, that take into account the probabilistic nature of the sampling process. We use presence-absence data collected under Pollock?s robust capture-recapture design, and resort to an estimator of species richness originally developed for closed populations to assess the proportion of species shared by different locations. We develop testable predictions corresponding to the null hypothesis of a nonnested pattern, and an alternative hypothesis of perfect nestedness. We also present an index for assessing the degree of nestedness of a system of ecological communities. We illustrate our approach using avian data from the North American Breeding Bird Survey collected in Florida Keys.

  14. Reactions of atomic oxygen with the chlorate ion and the perchlorate ion

    Science.gov (United States)

    Anan'ev, Vladimir; Miklin, Mikhail; Kriger, Ludmila

    2014-06-01

    The reactions of the chlorate ion with atomic oxygen formed under photolysis of the nitrate ion introduced to potassium chlorate crystal by co-crystallization were studied by optical and infrared absorption spectroscopy. The perchlorate ion was found to form in solids as product of addition reaction of singlet atomic oxygen, formed under dissociation of the peroxynitrite ion - the product of isomerization of the excited nitrate ion. Triplet atomic oxygen does not react with the chlorate ion. The atomic oxygen formed under photolysis of the nitrate ion introduced to potassium perchlorate crystal by co-crystallization does not react with the perchlorate ion.

  15. Three distinct subsets of thymic epithelial cells in rats and mice defined by novel antibodies.

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    Yasushi Sawanobori

    Full Text Available Thymic epithelial cells (TECs are thought to play an essential role in T cell development and have been detected mainly in mice using lectin binding and antibodies to keratins. Our aim in the present study was to create a precise map of rat TECs using antibodies to putative markers and novel monoclonal antibodies (i.e., ED 18/19/21 and anti-CD205 antibodies and compare it with a map from mouse counterparts and that of rat thymic dendritic cells.Rat TECs were subdivided on the basis of phenotype into three subsets; ED18+ED19+/-keratin 5 (K5+K8+CD205+ class II MHC (MHCII+ cortical TECs (cTECs, ED18+ED21-K5-K8+Ulex europaeus lectin 1 (UEA-1+CD205- medullary TECs (mTEC1s, and ED18+ED21+K5+K8dullUEA-1-CD205- medullary TECs (mTEC2s. Thymic nurse cells were defined in cytosmears as an ED18+ED19+/-K5+K8+ subset of cTECs. mTEC1s preferentially expressed MHCII, claudin-3, claudin-4, and autoimmune regulator (AIRE. Use of ED18 and ED21 antibodies revealed three subsets of TECs in mice as well. We also detected two distinct TEC-free areas in the subcapsular cortex and in the medulla. Rat dendritic cells in the cortex were MHCII+CD103+ but negative for TEC markers, including CD205. Those in the medulla were MHCII+CD103+ and CD205+ cells were found only in the TEC-free area.Both rats and mice have three TEC subsets with similar phenotypes that can be identified using known markers and new monoclonal antibodies. These findings will facilitate further analysis of TEC subsets and DCs and help to define their roles in thymic selection and in pathological states such as autoimmune disorders.

  16. NKT cell subsets as key participants in liver physiology and pathology

    Science.gov (United States)

    Bandyopadhyay, Keya; Marrero, Idania; Kumar, Vipin

    2016-01-01

    Natural killer T (NKT) cells are innate-like lymphocytes that generally recognize lipid antigens and are enriched in microvascular compartments of the liver. NKT cells can be activated by self- or microbial-lipid antigens and by signaling through toll-like receptors. Following activation, NKT cells rapidly secrete pro-inflammatory or anti-inflammatory cytokines and chemokines, and thereby determine the milieu for subsequent immunity or tolerance. It is becoming clear that two different subsets of NKT cells—type I and type II—have different modes of antigen recognition and have opposing roles in inflammatory liver diseases. Here we focus mainly on the roles of both NKT cell subsets in the maintenance of immune tolerance and inflammatory diseases in liver. Furthermore, how the differential activation of type I and type II NKT cells influences other innate cells and adaptive immune cells to result in important consequences for tissue integrity is discussed. It is crucial that better reagents, including CD1d tetramers, be used in clinical studies to define the roles of NKT cells in liver diseases in patients. PMID:26972772

  17. NKT cell subsets as key participants in liver physiology and pathology.

    Science.gov (United States)

    Bandyopadhyay, Keya; Marrero, Idania; Kumar, Vipin

    2016-05-01

    Natural killer T (NKT) cells are innate-like lymphocytes that generally recognize lipid antigens and are enriched in microvascular compartments of the liver. NKT cells can be activated by self- or microbial-lipid antigens and by signaling through toll-like receptors. Following activation, NKT cells rapidly secrete pro-inflammatory or anti-inflammatory cytokines and chemokines, and thereby determine the milieu for subsequent immunity or tolerance. It is becoming clear that two different subsets of NKT cells-type I and type II-have different modes of antigen recognition and have opposing roles in inflammatory liver diseases. Here we focus mainly on the roles of both NKT cell subsets in the maintenance of immune tolerance and inflammatory diseases in liver. Furthermore, how the differential activation of type I and type II NKT cells influences other innate cells and adaptive immune cells to result in important consequences for tissue integrity is discussed. It is crucial that better reagents, including CD1d tetramers, be used in clinical studies to define the roles of NKT cells in liver diseases in patients.

  18. Restoration of STORM images from sparse subset of localizations (Conference Presentation)

    Science.gov (United States)

    Moiseev, Alexander A.; Gelikonov, Grigory V.; Gelikonov, Valentine M.

    2016-02-01

    To construct a Stochastic Optical Reconstruction Microscopy (STORM) image one should collect sufficient number of localized fluorophores to satisfy Nyquist criterion. This requirement limits time resolution of the method. In this work we propose a probabalistic approach to construct STORM images from a subset of localized fluorophores 3-4 times sparser than required from Nyquist criterion. Using a set of STORM images constructed from number of localizations sufficient for Nyquist criterion we derive a model which allows us to predict the probability for every location to be occupied by a fluorophore at the end of hypothetical acquisition, having as an input parameters distribution of already localized fluorophores in the proximity of this location. We show that probability map obtained from number of fluorophores 3-4 times less than required by Nyquist criterion may be used as superresolution image itself. Thus we are able to construct STORM image from a subset of localized fluorophores 3-4 times sparser than required from Nyquist criterion, proportionaly decreasing STORM data acquisition time. This method may be used complementary with other approaches desined for increasing STORM time resolution.

  19. Data on correlations between T cell subset frequencies and length of partial remission in type 1 diabetes

    Directory of Open Access Journals (Sweden)

    Aditi Narsale

    2016-09-01

    Full Text Available Partial remission in patients newly diagnosed with type 1 diabetes is a period of good glucose control that can last from several weeks to over a year. The clinical significance of the remission period is that patients might be more responsive to immunotherapy if treated within this period. This article provides clinical data that indicates the level of glucose control and insulin-secreting β-cell function of each patient in the study at baseline (within 3 months of diagnosis, and at 3, 6, 9, 12, 18 and 24 months post-baseline. The relative frequency of immune cell subsets in the PBMC of each patient and the association between the frequency of immune cell subsets measured and length of remission is also shown. These data support the findings reported in the accompanying publication, “A pilot study showing associations between frequency of CD4+ memory cell subsets at diagnosis and duration of partial remission in type 1 diabetes” (Moya et al., 2016 [1], where a full interpretation, including biological relevance of the study can be found. Keywords: Type 1 diabetes, T cell subsets, Partial remission

  20. Lymphocyte subsets in human immunodeficiency virus-unexposed Brazilian individuals from birth to adulthood

    Directory of Open Access Journals (Sweden)

    Maria Isabel de Moraes-Pinto

    2014-12-01

    Full Text Available Ethnic origin, genetics, gender and environmental factors have been shown to influence some immunologic indices, so that development of reference values for populations of different backgrounds may be necessary. We have determined the distribution of lymphocyte subsets in healthy Brazilian individuals from birth to adulthood. Lymphocyte subsets were determined using four-colour cytometry in a cross-sectional study of 463 human immunodeficiency virus-unexposed children and adults from birth through 49 years of age. Lymphocyte subsets varied according to age, as previously observed in other studies. However, total CD4+ T cell numbers were lower than what was described in the Pediatric AIDS Clinical Trials Group P1009 (PACTG P1009, which assessed an American population of predominantly African and Hispanic backgrounds until the 12-18 year age range, when values were comparable. Naïve percentages and absolute values of CD8+ T cells, as assessed by CD45RA expression, were also lower than the PACTG P1009 data for all analysed age ranges. CD38 expression on both CD4+ and CD8+ T cells was lower than the PACTG P1009 values, with a widening gap between the two studies at older age ranges. Different patterns of cell differentiation seem to occur in different settings and may have characteristic expression within each population.

  1. NKT Cell Subsets Can Exert Opposing Effects in Autoimmunity, Tumor Surveillance and Inflammation

    Science.gov (United States)

    Viale, Rachael; Ware, Randle; Maricic, Igor; Chaturvedi, Varun; Kumar, Vipin

    2014-01-01

    The innate-like natural killer T (NKT) cells are essential regulators of immunity. These cells comprise at least two distinct subsets and recognize different lipid antigens presented by the MHC class I like molecules CD1d. The CD1d-dependent recognition pathway of NKT cells is highly conserved from mouse to humans. While most type I NKT cells can recognize αGalCer and express a semi-invariant T cell receptor (TCR), a major population of type II NKT cells reactive to sulfatide utilizes an oligoclonal TCR. Furthermore TCR recognition features of NKT subsets are also distinctive with almost parallel as opposed to perpendicular footprints on the CD1d molecules for the type I and type II NKT cells respectively. Here we present a view based upon the recent studies in different clinical and experimental settings that while type I NKT cells are more often pathogenic, they may also be regulatory. On the other hand, sulfatide-reactive type II NKT cells mostly play an inhibitory role in the control of autoimmune and inflammatory diseases. Since the activity and cytokine secretion profiles of NKT cell subsets can be modulated differently by lipid ligands or their analogs, novel immunotherapeutic strategies are being developed for their differential activation for potential intervention in inflammatory diseases. PMID:25288922

  2. Molecular marker differences relate to developmental position and subsets of mesodiencephalic dopaminergic neurons.

    Directory of Open Access Journals (Sweden)

    Simone M Smits

    Full Text Available The development of mesodiencephalic dopaminergic (mdDA neurons located in the substantia nigra compacta (SNc and ventral tegmental area (VTA follow a number of stages marked by distinct events. After preparation of the region by signals that provide induction and patterning, several transcription factors have been identified, which are involved in specifying the neuronal fate of these cells. The specific vulnerability of SNc neurons is thought to root in these specific developmental programs. The present study examines the positions of young postmitotic mdDA neurons to relate developmental position to mdDA subset specific markers. MdDA neurons were mapped relative to the neuromeric domains (prosomeres 1-3 (P1-3, midbrain, and hindbrain as well as the longitudinal subdivisions (floor plate, basal plate, alar plate, as proposed by the prosomeric model. We found that postmitotic mdDA neurons are located mainly in the floorplate domain and very few in slightly more lateral domains. Moreover, mdDA neurons are present along a large proportion of the anterior/posterior axis extending from the midbrain to P3 in the diencephalon. The specific positions relate to some extent to the presence of specific subset markers as Ahd2. In the adult stage more of such subsets specific expressed genes are present and may represent a molecular map defining molecularly distinct groups of mdDA neurons.

  3. Change of T, B lymphocyte subsets and Th1/Th2 indexes of patients with recurrent spontaneous abortion

    Institute of Scientific and Technical Information of China (English)

    Shi-Hua Zhou

    2016-01-01

    Objective:To analyze and investigate the change state of T, B lymphocyte subsets and Th1/Th2 indexes of patients with recurrent spontaneous abortion. Methods: A total of 92 patients with recurrent spontaneous abortion in our hospital from June 2013 to July 2015 were selected as the observation group and 92 women with health delivery history at the same time were selected as the control group,then the peripheral blood T, B lymphocyte subsets and Th1/Th2 indexes of two groups were detected and compared and the peripheral blood T, B lymphocyte subsets and Th1/Th2 indexes of patients with different gestational age at abortion and abortion times were compared too. Results:The peripheral blood T, B lymphocyte subsets and Th1/Th2 indexes of observation group and control group all had obvious differences,and those blood indexes levels' differences of patients with different gestational age at abortion and abortion times were obvious too, all P<0.05 and the differences were significant. Conclusions: The T, B lymphocyte subsets and Th1/Th2 indexes of patients with recurrent spontaneous abortion show abnormal state and the differences of detection results of patients with different gestational age at abortion and abortion times are relatively obvious,so those indexes should be monitored and improved intentinonally.

  4. Peripheral blood and milk leukocytes subsets of lactating Sarda ewes

    Directory of Open Access Journals (Sweden)

    Piero Bonelli

    2013-05-01

    Full Text Available Leukocytes subpopulations in blood and milk of lactating Sarda ewes were investigated. Animals characterized by a SSC level <500×103cells/mL and a negative bacteriological examination were sampled in early, mid and late lactation. Milk differential cell count evidenced that macrophage represented the main population (42.8%±3.5 followed by lymphocytes (40.2%±3.4 and neutrophils (8,6%±2.1. Flow cytometry analysis showed that lymphocytes subsets in milk were quite different from blood. High CD8+ and low CD4+ lymphocytes percentages determined a CD4/CD8 ratio inversion in milk compared to blood (0.3%±0.03 vs 1.8%±0.08. CD8+ decreased while, conversely, CD4+ increased in late lactation. γδ T cells were more represented in milk (12.6%±1.3 than in blood (6.8%±0.3 and their proportions appeared similar throughout lactation in both compartments. IL-2 receptor was mainly expressed in milk on T cytotoxic lymphocytes. Data obtained in uninfected mammary glands could allow an early discrimination between physiological and pathological changes occurring in ewe milk. Further phenotypical and functional studies on milk leukocytes subsets might help to understand defense mechanisms of the ovine mammary gland against IMI.

  5. Differential Aspartate Usage Identifies a Subset of Cancer Cells Particularly Dependent on OGDH

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    Eric L. Allen

    2016-10-01

    Full Text Available Although aberrant metabolism in tumors has been well described, the identification of cancer subsets with particular metabolic vulnerabilities has remained challenging. Here, we conducted an siRNA screen focusing on enzymes involved in the tricarboxylic acid (TCA cycle and uncovered a striking range of cancer cell dependencies on OGDH, the E1 subunit of the alpha-ketoglutarate dehydrogenase complex. Using an integrative metabolomics approach, we identified differential aspartate utilization, via the malate-aspartate shuttle, as a predictor of whether OGDH is required for proliferation in 3D culture assays and for the growth of xenograft tumors. These findings highlight an anaplerotic role of aspartate and, more broadly, suggest that differential nutrient utilization patterns can identify subsets of cancers with distinct metabolic dependencies for potential pharmacological intervention.

  6. Brain magnetic resonance imaging with contrast dependent on blood oxygenation

    International Nuclear Information System (INIS)

    Ogawa, S.; Lee, T.M.; Kay, A.R.; Tank, D.W.

    1990-01-01

    Paramagnetic deoxyhemoglobin in venous blood is a naturally occurring contrast agent for magnetic resonance imaging (MRI). By accentuating the effects of this agent through the use of gradient-echo techniques in high yields, the authors demonstrate in vivo images of brain microvasculature with image contrast reflecting the blood oxygen level. This blood oxygenation level-dependent (BOLD) contrast follows blood oxygen changes induced by anesthetics, by insulin-induced hypoglycemia, and by inhaled gas mixtures that alter metabolic demand or blood flow. The results suggest that BOLD contrast can be used to provide in vivo real-time maps of blood oxygenation in the brain under normal physiological conditions. BOLD contrast adds an additional feature to magnetic resonance imaging and complement other techniques that are attempting to provide position emission tomography-like measurements related to regional neural activity

  7. Comparison of the Functional microRNA Expression in Immune Cell Subsets of Neonates and Adults

    Science.gov (United States)

    Yu, Hong-Ren; Hsu, Te-Yao; Huang, Hsin-Chun; Kuo, Ho-Chang; Li, Sung-Chou; Yang, Kuender D.; Hsieh, Kai-Sheng

    2016-01-01

    Diversity of biological molecules in newborn and adult immune cells contributes to differences in cell function and atopic properties. Micro RNAs (miRNAs) are reported to involve in the regulation of immune system. Therefore, determining the miRNA expression profile of leukocyte subpopulations is important for understanding immune system regulation. In order to explore the unique miRNA profiling that contribute to altered immune in neonates, we comprehensively analyzed the functional miRNA signatures of eight leukocyte subsets (polymorphonuclear cells, monocytes, CD4+ T cells, CD8+ T cells, natural killer cells, B cells, plasmacytoid dendritic cells, and myeloid dendritic cells) from both neonatal and adult umbilical cord and peripheral blood samples, respectively. We observed distinct miRNA profiles between adult and neonatal blood leukocyte subsets, including unique miRNA signatures for each cell lineage. Leukocyte miRNA signatures were altered after stimulation. Adult peripheral leukocytes had higher let-7b-5p expression levels compared to neonatal cord leukocytes across multiple subsets, irrespective of stimulation. Transfecting neonatal monocytes with a let-7b-5p mimic resulted in a reduction of LPS-induced interleukin (IL)-6 and TNF-α production, while transfection of a let-7b-5p inhibitor into adult monocytes enhanced IL-6 and TNF-α production. With this functional approach, we provide intact differential miRNA expression profiling of specific immune cell subsets between neonates and adults. These studies serve as a basis to further understand the altered immune response observed in neonates and advance the development of therapeutic strategies. PMID:28066425

  8. Comparison of the functional microRNA expression in immune cell subsets of neonates and adults

    Directory of Open Access Journals (Sweden)

    Hong-Ren Yu

    2016-12-01

    Full Text Available Diversity of biological molecules in newborn and adult immune cells contributes to differences in cell function and atopic properties. Micro RNAs (miRNAs are reported involve in the regulation of immune system. Therefore, determining the miRNA expression profile of leukocyte sub-populations is important for understanding immune system regulation. In order to explore the unique microRNA profiling that contribute to altered immune in neonates, we comprehensively analyzed the functional miRNA signatures of eight leukocyte subsets (polymorphonuclear cells, monocytes, CD4+ T cells, CD8+ T cells, natural killer cells, B cells, plasmacytoid dendritic cells (pDCs, and myeloid dendritic cells (mDCs from both neonatal and adult umbilical cord and peripheral blood samples, respectively. We observed distinct miRNA profiles between adult and neonatal blood leukocyte subsets, including unique miRNA signatures for each cell lineage. Leukocyte miRNA signatures were altered after stimulation. Adult peripheral leukocytes had higher let-7b-5p expression levels compared to neonatal cord leukocytes across multiple subsets, irrespective of stimulation. Transfecting neonatal monocytes with a let-7b-5p mimic resulted in a reduction of LPS-induced IL-6 and TNF-alpha production, while transfection of a let-7b-5p inhibitor into adult monocytes enhanced IL-6 and TNF-alpha production. With this functional approach, we provide intact differential microRNA expression profiling of specific immune cell subsets between neonates and adults. These studies serve as a basis to further understand the altered immune response observed in neonates and advance the development of therapeutic strategies.

  9. L1-Penalized N-way PLS for subset of electrodes selection in BCI experiments

    Science.gov (United States)

    Eliseyev, Andrey; Moro, Cecile; Faber, Jean; Wyss, Alexander; Torres, Napoleon; Mestais, Corinne; Benabid, Alim Louis; Aksenova, Tetiana

    2012-08-01

    Recently, the N-way partial least squares (NPLS) approach was reported as an effective tool for neuronal signal decoding and brain-computer interface (BCI) system calibration. This method simultaneously analyzes data in several domains. It combines the projection of a data tensor to a low dimensional space with linear regression. In this paper the L1-Penalized NPLS is proposed for sparse BCI system calibration, allowing uniting the projection technique with an effective selection of subset of features. The L1-Penalized NPLS was applied for the binary self-paced BCI system calibration, providing selection of electrodes subset. Our BCI system is designed for animal research, in particular for research in non-human primates.

  10. Influence of the temperature and oxygen exposure in red Port wine: A kinetic approach.

    Science.gov (United States)

    Oliveira, Carla Maria; Barros, António S; Silva Ferreira, António César; Silva, Artur M S

    2015-09-01

    Although phenolics are recognized to be related with health benefits by limiting lipid oxidation, in wine, they are the primary substrates for oxidation resulting in the quinone by-products with the participation of transition metal ions. Nevertheless, high quality Port wines require a period of aging in either bottle or barrels. During this time, a modification of sensory properties of wines such as the decrease of astringency or the stabilization of color is recognized to phenolic compounds, mainly attributed to anthocyanins and derived pigments. The present work aims to illustrate the oxidation of red Port wine based on its phenolic composition by the effect of both thermal and oxygen exposures. A kinetic approach toanthocyanins degradation was also achieved. For this purpose a forced red Port wine aging protocol was performed at four different storage temperatures, respectively, 20, 30, 35 and 40°C, and two adjusted oxygen saturation levels, no oxygen addition (treatment I), and oxygen addition (treatment II). Three hydroxycinnamic esters, three hydroxycinnamic acids, three hydroxybenzoic acids, two flavan-3-ols, and six anthocyanins were quantitated weekly during 63days, along with oxygen consumption. The most relevant phenolic oxidation markers were anthocyanins and catechin-type flavonoids, which had the highest decreases during the thermal and oxidative red Port wine process. Both temperature and oxygen treatments affected the rate of phenolic degradation. In addition, temperature seems to influence mostly the phenolics kinetic degradation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Type II NKT cells: a distinct CD1d-restricted immune regulatory NKT cell subset.

    Science.gov (United States)

    Dasgupta, Suryasarathi; Kumar, Vipin

    2016-08-01

    Type II natural killer T cells (NKT) are a subset of the innate-like CD1d-restricted lymphocytes that are reactive to lipid antigens. Unlike the type I NKT cells, which express a semi-invariant TCR, type II NKT cells express a broader TCR repertoire. Additionally, other features, such as their predominance over type I cells in humans versus mice, the nature of their ligands, CD1d/lipid/TCR binding, and modulation of immune responses, distinguish type II NKT cells from type I NKT cells. Interestingly, it is the self-lipid-reactivity of type II NKT cells that has helped define their physiological role in health and in disease. The discovery of sulfatide as one of the major antigens for CD1d-restricted type II NKT cells in mice has been instrumental in the characterization of these cells, including the TCR repertoire, the crystal structure of the CD1d/lipid/TCR complex, and their function. Subsequently, several other glycolipids and phospholipids from both endogenous and microbial sources have been shown to activate type II NKT cells. The activation of a specific subset of type II NKT cells following administration with sulfatide or lysophosphatidylcholine (LPC) leads to engagement of a dominant immunoregulatory pathway associated with the inactivation of type I NKT cells, conventional dendritic cells, and inhibition of the proinflammatory Th1/Th17 cells. Thus, type II NKT cells have been shown to be immunosuppressive in autoimmune diseases, inflammatory liver diseases, and in cancer. Knowing their relatively higher prevalence in human than type I NKT cells, understanding their biology is imperative for health and disease.

  12. A 3D-Printed Oxygen Control Insert for a 24-Well Plate.

    Directory of Open Access Journals (Sweden)

    Martin D Brennan

    Full Text Available 3D printing has emerged as a method for directly printing complete microfluidic devices, although printing materials have been limited to oxygen-impermeable materials. We demonstrate the addition of gas permeable PDMS (Polydimethylsiloxane membranes to 3D-printed microfluidic devices as a means to enable oxygen control cell culture studies. The incorporation of a 3D-printed device and gas-permeable membranes was demonstrated on a 24-well oxygen control device for standard multiwell plates. The direct printing allows integrated distribution channels and device geometries not possible with traditional planar lithography. With this device, four different oxygen conditions were able to be controlled, and six wells were maintained under each oxygen condition. We demonstrate enhanced transcription of the gene VEGFA (vascular endothelial growth factor A with decreasing oxygen levels in human lung adenocarcinoma cells. This is the first 3D-printed device incorporating gas permeable membranes to facilitate oxygen control in cell culture.

  13. Storage capacity and oxygen mobility in mixed oxides from transition metals promoted by cerium

    Energy Technology Data Exchange (ETDEWEB)

    Perdomo, Camilo [Estado Sólido y Catálisis Ambiental (ESCA), Departamento de Química, Facultad de Ciencias, Universidad Nacional de Colombia, Carrera 30 45-03, Bogotá (Colombia); Pérez, Alejandro [Grupo de Investigación Fitoquímica (GIFUJ), Departamento de Química, Facultad de Ciencias, Pontificia Universidad Javeriana, Carrera 7 No. 43-82, Bogotá D.C (Colombia); Molina, Rafael [Estado Sólido y Catálisis Ambiental (ESCA), Departamento de Química, Facultad de Ciencias, Universidad Nacional de Colombia, Carrera 30 45-03, Bogotá (Colombia); Moreno, Sonia, E-mail: smorenog@unal.edu.co [Estado Sólido y Catálisis Ambiental (ESCA), Departamento de Química, Facultad de Ciencias, Universidad Nacional de Colombia, Carrera 30 45-03, Bogotá (Colombia)

    2016-10-15

    Highlights: • Ce addition to the catalysts improves the availability of oxygen in the materials. • Mixed oxide with Co and Cu exhibits the best oxygen transport properties. • Co presence improves O{sub 2} mobility in the catalysts. • The presence of Cu in the solids improves redox properties. - Abstract: The oxygen mobility and storage capacity of Ce-Co/Cu-MgAl or Ce–MgAl mixed oxides, obtained by hydrotalcite precursors, were evaluated using Toluene-temperature-programmed-reaction, {sup 18}O{sub 2} isotopic exchange and O{sub 2}-H{sub 2} titration. The presence of oxygen vacancies-related species was evaluated by means of Electron Paramagnetic Resonance. A correlation was found between the studied properties and the catalytic activity of the oxides in total oxidation processes. It was evidenced that catalytic activity depends on two related processes: the facility with which the solid can be reduced and its ability to regenerate itself in the presence of molecular oxygen in the gas phase. These processes are enhanced by Cu-Co cooperative effect in the mixed oxides. Additionally, the incorporation of Ce in the Co-Cu catalysts improved their oxygen transport properties.

  14. Storage capacity and oxygen mobility in mixed oxides from transition metals promoted by cerium

    International Nuclear Information System (INIS)

    Perdomo, Camilo; Pérez, Alejandro; Molina, Rafael; Moreno, Sonia

    2016-01-01

    Highlights: • Ce addition to the catalysts improves the availability of oxygen in the materials. • Mixed oxide with Co and Cu exhibits the best oxygen transport properties. • Co presence improves O 2 mobility in the catalysts. • The presence of Cu in the solids improves redox properties. - Abstract: The oxygen mobility and storage capacity of Ce-Co/Cu-MgAl or Ce–MgAl mixed oxides, obtained by hydrotalcite precursors, were evaluated using Toluene-temperature-programmed-reaction, 18 O 2 isotopic exchange and O 2 -H 2 titration. The presence of oxygen vacancies-related species was evaluated by means of Electron Paramagnetic Resonance. A correlation was found between the studied properties and the catalytic activity of the oxides in total oxidation processes. It was evidenced that catalytic activity depends on two related processes: the facility with which the solid can be reduced and its ability to regenerate itself in the presence of molecular oxygen in the gas phase. These processes are enhanced by Cu-Co cooperative effect in the mixed oxides. Additionally, the incorporation of Ce in the Co-Cu catalysts improved their oxygen transport properties.

  15. dbVOR: a database system for importing pedigree, phenotype and genotype data and exporting selected subsets.

    Science.gov (United States)

    Baron, Robert V; Conley, Yvette P; Gorin, Michael B; Weeks, Daniel E

    2015-03-18

    When studying the genetics of a human trait, we typically have to manage both genome-wide and targeted genotype data. There can be overlap of both people and markers from different genotyping experiments; the overlap can introduce several kinds of problems. Most times the overlapping genotypes are the same, but sometimes they are different. Occasionally, the lab will return genotypes using a different allele labeling scheme (for example 1/2 vs A/C). Sometimes, the genotype for a person/marker index is unreliable or missing. Further, over time some markers are merged and bad samples are re-run under a different sample name. We need a consistent picture of the subset of data we have chosen to work with even though there might possibly be conflicting measurements from multiple data sources. We have developed the dbVOR database, which is designed to hold data efficiently for both genome-wide and targeted experiments. The data are indexed for fast retrieval by person and marker. In addition, we store pedigree and phenotype data for our subjects. The dbVOR database allows us to select subsets of the data by several different criteria and to merge their results into a coherent and consistent whole. Data may be filtered by: family, person, trait value, markers, chromosomes, and chromosome ranges. The results can be presented in columnar, Mega2, or PLINK format. dbVOR serves our needs well. It is freely available from https://watson.hgen.pitt.edu/register . Documentation for dbVOR can be found at https://watson.hgen.pitt.edu/register/docs/dbvor.html .

  16. Utilization of Renewable Oxygenates as Gasoline Blending Components

    Energy Technology Data Exchange (ETDEWEB)

    Yanowitz, J.; Christensen, E.; McCormick, R. L.

    2011-08-01

    This report reviews the use of higher alcohols and several cellulose-derived oxygenates as blend components in gasoline. Material compatibility issues are expected to be less severe for neat higher alcohols than for fuel-grade ethanol. Very little data exist on how blending higher alcohols or other oxygenates with gasoline affects ASTM Standard D4814 properties. Under the Clean Air Act, fuels used in the United States must be 'substantially similar' to fuels used in certification of cars for emission compliance. Waivers for the addition of higher alcohols at concentrations up to 3.7 wt% oxygen have been granted. Limited emission testing on pre-Tier 1 vehicles and research engines suggests that higher alcohols will reduce emissions of CO and organics, while NOx emissions will stay the same or increase. Most oxygenates can be used as octane improvers for standard gasoline stocks. The properties of 2-methyltetrahydrofuran, dimethylfuran, 2-methylfuran, methyl pentanoate and ethyl pentanoate suggest that they may function well as low-concentration blends with gasoline in standard vehicles and in higher concentrations in flex fuel vehicles.

  17. Integration of oxygen signaling at the consensus HRE.

    Science.gov (United States)

    Wenger, Roland H; Stiehl, Daniel P; Camenisch, Gieri

    2005-10-18

    The hypoxia-inducible factor 1 (HIF-1) was initially identified as a transcription factor that regulated erythropoietin gene expression in response to a decrease in oxygen availability in kidney tissue. Subsequently, a family of oxygen-dependent protein hydroxylases was found to regulate the abundance and activity of three oxygen-sensitive HIFalpha subunits, which, as part of the HIF heterodimer, regulated the transcription of at least 70 different effector genes. In addition to responding to a decrease in tissue oxygenation, HIF is proactively induced, even under normoxic conditions, in response to stimuli that lead to cell growth, ultimately leading to higher oxygen consumption. The growing cell thus profits from an anticipatory increase in HIF-dependent target gene expression. Growth stimuli-activated signaling pathways that influence the abundance and activity of HIFs include pathways in which kinases are activated and pathways in which reactive oxygen species are liberated. These pathways signal to the HIF protein hydroxylases, as well as to HIF itself, by means of covalent or redox modifications and protein-protein interactions. The final point of integration of all of these pathways is the hypoxia-response element (HRE) of effector genes. Here, we provide comprehensive compilations of the known growth stimuli that promote increases in HIF abundance, of protein-protein interactions involving HIF, and of the known HIF effector genes. The consensus HRE derived from a comparison of the HREs of these HIF effectors will be useful for identification of novel HIF target genes, design of oxygen-regulated gene therapy, and prediction of effects of future drugs targeting the HIF system.

  18. Cerebellins are differentially expressed in selective subsets of neurons throughout the brain.

    Science.gov (United States)

    Seigneur, Erica; Südhof, Thomas C

    2017-10-15

    Cerebellins are secreted hexameric proteins that form tripartite complexes with the presynaptic cell-adhesion molecules neurexins or 'deleted-in-colorectal-cancer', and the postsynaptic glutamate-receptor-related proteins GluD1 and GluD2. These tripartite complexes are thought to regulate synapses. However, cerebellins are expressed in multiple isoforms whose relative distributions and overall functions are not understood. Three of the four cerebellins, Cbln1, Cbln2, and Cbln4, autonomously assemble into homohexamers, whereas the Cbln3 requires Cbln1 for assembly and secretion. Here, we show that Cbln1, Cbln2, and Cbln4 are abundantly expressed in nearly all brain regions, but exhibit strikingly different expression patterns and developmental dynamics. Using newly generated knockin reporter mice for Cbln2 and Cbln4, we find that Cbln2 and Cbln4 are not universally expressed in all neurons, but only in specific subsets of neurons. For example, Cbln2 and Cbln4 are broadly expressed in largely non-overlapping subpopulations of excitatory cortical neurons, but only sparse expression was observed in excitatory hippocampal neurons of the CA1- or CA3-region. Similarly, Cbln2 and Cbln4 are selectively expressed, respectively, in inhibitory interneurons and excitatory mitral projection neurons of the main olfactory bulb; here, these two classes of neurons form dendrodendritic reciprocal synapses with each other. A few brain regions, such as the nucleus of the lateral olfactory tract, exhibit astoundingly high Cbln2 expression levels. Viewed together, our data show that cerebellins are abundantly expressed in relatively small subsets of neurons, suggesting specific roles restricted to subsets of synapses. © 2017 Wiley Periodicals, Inc.

  19. Oxygen-Partial-Pressure Sensor for Aircraft Oxygen Mask

    Science.gov (United States)

    Kelly, Mark; Pettit, Donald

    2003-01-01

    A device that generates an alarm when the partial pressure of oxygen decreases to less than a preset level has been developed to help prevent hypoxia in a pilot or other crewmember of a military or other high-performance aircraft. Loss of oxygen partial pressure can be caused by poor fit of the mask or failure of a hose or other component of an oxygen distribution system. The deleterious physical and mental effects of hypoxia cause the loss of a military aircraft and crew every few years. The device is installed in the crewmember s oxygen mask and is powered via communication wiring already present in all such oxygen masks. The device (see figure) includes an electrochemical sensor, the output potential of which is proportional to the partial pressure of oxygen. The output of the sensor is amplified and fed to the input of a comparator circuit. A reference potential that corresponds to the amplified sensor output at the alarm oxygen-partial-pressure level is fed to the second input of the comparator. When the sensed partial pressure of oxygen falls below the minimum acceptable level, the output of the comparator goes from the low state (a few millivolts) to the high state (near the supply potential, which is typically 6.8 V for microphone power). The switching of the comparator output to the high state triggers a tactile alarm in the form of a vibration in the mask, generated by a small 1.3-Vdc pager motor spinning an eccentric mass at a rate between 8,000 and 10,000 rpm. The sensation of the mask vibrating against the crewmember s nose is very effective at alerting the crewmember, who may already be groggy from hypoxia and is immersed in an environment that is saturated with visual cues and sounds. Indeed, the sensation is one of rudeness, but such rudeness could be what is needed to stimulate the crewmember to take corrective action in a life-threatening situation.

  20. Oxygen incineration process for treatment of alpha-contaminated wastes

    International Nuclear Information System (INIS)

    Kim, Jeong Guk; Yang, Hee Chul; Park, Geun Il; Kim, In Tae; Kim, Joon Hyung

    2001-07-01

    As a part of development of a treatment technology for burnable alpha-bearing (or -contaminated) wastes using an oxygen incineration process, which would be expected to produce in Korea, the off-gas volume and compositions were estimated form mass and heat balance, and then compared to those of a general air incineration process. A laboratory-scale oxygen incineration process, to investigate a burnable wastes from nuclear fuel fabricatin facility, was designed, constructed, and then operated. The use of oxygen instead of air in incineratin would result in reduction on off-gas product below one seventh theoretically. In addition, the trends on incineration and melting processes to treat the radioactive alpha-contaminated wastes, and the regulations and guide lines, related to design, construction, and operation of incineration process, were reviewed. Finallu, the domestic regulations related incineration, and the operation and maintenance manuals for oxy-fuel burner and oxygen incineration process were shown in appendixes

  1. Oxygen incineration process for treatment of alpha-contaminated wastes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jeong Guk; Yang, Hee Chul; Park, Geun Il; Kim, In Tae; Kim, Joon Hyung

    2001-07-01

    As a part of development of a treatment technology for burnable alpha-bearing (or -contaminated) wastes using an oxygen incineration process, which would be expected to produce in Korea, the off-gas volume and compositions were estimated form mass and heat balance, and then compared to those of a general air incineration process. A laboratory-scale oxygen incineration process, to investigate a burnable wastes from nuclear fuel fabricatin facility, was designed, constructed, and then operated. The use of oxygen instead of air in incineratin would result in reduction on off-gas product below one seventh theoretically. In addition, the trends on incineration and melting processes to treat the radioactive alpha-contaminated wastes, and the regulations and guide lines, related to design, construction, and operation of incineration process, were reviewed. Finallu, the domestic regulations related incineration, and the operation and maintenance manuals for oxy-fuel burner and oxygen incineration process were shown in appendixes.

  2. Oxygen, a Key Factor Regulating Cell Behavior during Neurogenesis and Cerebral Diseases.

    Science.gov (United States)

    Zhang, Kuan; Zhu, Lingling; Fan, Ming

    2011-01-01

    Oxygen is vital to maintain the normal functions of almost all the organs, especially for brain which is one of the heaviest oxygen consumers in the body. The important roles of oxygen on the brain are not only reflected in the development, but also showed in the pathological processes of many cerebral diseases. In the current review, we summarized the oxygen levels in brain tissues tested by real-time measurements during the embryonic and adult neurogenesis, the cerebral diseases, or in the hyperbaric/hypobaric oxygen environment. Oxygen concentration is low in fetal brain (0.076-7.6 mmHg) and in adult brain (11.4-53.2 mmHg), decreased during stroke, and increased in hyperbaric oxygen environment. In addition, we reviewed the effects of oxygen tensions on the behaviors of neural stem cells (NSCs) in vitro cultures at different oxygen concentration (15.2-152 mmHg) and in vivo niche during different pathological states and in hyperbaric/hypobaric oxygen environment. Moderate hypoxia (22.8-76 mmHg) can promote the proliferation of NSCs and enhance the differentiation of NSCs into the TH-positive neurons. Next, we briefly presented the oxygen-sensitive molecular mechanisms regulating NSCs proliferation and differentiation recently found including the Notch, Bone morphogenetic protein and Wnt pathways. Finally, the future perspectives about the roles of oxygen on brain and NSCs were given.

  3. Oxygen, a key factor regulating cell behaviour during neurogenesis and cerebral diseases

    Directory of Open Access Journals (Sweden)

    Kuan eZhang

    2011-04-01

    Full Text Available Oxygen is vital to maintain the normal functions of alomost all the organs, especially for brain which is one of the heaviest oxygen consumers in the body. The important roles of oxygen on the brain are not only reflected in the development, but also showed in the pathological processes of many cerebral diseases. In the current review, we summarized the oxygen levels in brain tissues tested by real-time measurements during the embryonic and adult neurogenesis, the cerebral diseases or in the hyperbaric/hypobaric oxygen environment. Oxygen concentration is low in fetal brain (0.01%- 1% and in adult brain (1.5%-7%, decreased during stroke, and increased in hyperbaric oxygen environment. In addition, we reviewed the effects of oxygen tensions on the behaviors of neural stem cells (NSCs in vitro cultures at different oxygen concentration (2%-20% and in vivo niche during different pathological states and in hyperbaric/hypobaric oxygen environment. Moderate hypoxia (3%-10% is known can promote the proliferation of NSCs and enhance the differentiation of NSCs into the TH-positive neurons. Next, we briefly presented the oxygen-sensitive molecular mechanisms regulating NSCs proliferation and differentiation recently found including the Notch, BMP and Wnt pathways. Finally, the future perspectives about the roles of oxygen on brain and NSCs were given.

  4. Increase in a distinct pulmonary macrophage subset possessing an antigen-presenting cell phenotype and in vitro APC activity following silica exposure

    International Nuclear Information System (INIS)

    Migliaccio, Christopher T.; Hamilton, Raymond F.; Holian, Andrij

    2005-01-01

    Silica inhalation results in chronic lung inflammation and fibrosis. While the role of the alveolar macrophage (AM) is considered key to the effects of silica on lung pathology, the etiology is not completely understood. Evidence suggests an increase in antigen presenting cell (APC) activity as a contributing factor to this process, as well as potential roles for both AM and interstitial macrophages (IM) in silicosis. In order to study the effects of crystalline silica on the APC activity of pulmonary macrophages, mice were exposed intranasally and changes in pulmonary macrophage populations were assessed using flow cytometry. Following intranasal instillation of silica, a significant increase in the APC activity of AM was observed, as well as a significant increase in a subset of IM expressing classic APC markers (MHC class II, CD11c). In addition, an in vitro system using bone marrow-derived macrophages (BMDM) was generated to assess the effects of silica on the APC activity of macrophages in vitro. Data using BMDM in the in vitro APC assay demonstrated a significant increase in APC activity following silica exposure, but not following exposure to saline or a control particle (TiO 2 ). Using a combination of in vivo and in vitro experiments, the current study describes a significant increase in an interstitial macrophage subset with an APC phenotype, as well as an increase in the APC activity of both AM and BMDM, as a direct result of exposure to crystalline silica. These studies suggest a specific mechanism, macrophage subset activation, by which crystalline silica exposure results in chronic pulmonary inflammation and, eventually, fibrosis

  5. Oxygen Transport Membrane Reactors for Oxy-Fuel Combustion and Carbon Capture Purposes

    Science.gov (United States)

    Falkenstein-Smith, Ryan L.

    This thesis investigates oxygen transport membrane reactors (OTMs) for the application of oxy-fuel combustion. This is done by evaluating the material properties and oxygen permeability of different OTM compositions subjected to a variety of operating conditions. The scope of this work consists of three components: (1) evaluate the oxygen permeation capabilities of perovskite-type materials for the application of oxy-fuel combustion; (2) determine the effects of dual-phase membrane compositions on the oxygen permeation performance and membrane characteristics; and (3) develop a new method for estimating the oxygen permeation performance of OTMs utilized for the application of oxy-fuel combustion. SrSc0.1Co0.9O3-delta (SSC) is selected as the primary perovskite-type material used in this research due to its reported high ionic and electronic conductive properties and chemical stability. SSC's oxygen ion diffusivity is investigated using a conductivity relaxation technique and thermogravimetric analysis. Material properties such as chemical structure, morphology, and ionic and electronic conductivity are examined by X-ray diffraction (XRD), Scanning Electron Microscope (SEM), and conductivity testing using a four-probe method, respectively. Oxygen permeation tests study the oxygen permeability OTMs under modified membrane temperatures, sweeping gas flow rates, sweeping gas compositions, membrane configurations, and membrane compositions. When utilizing a pure CO2 sweeping gas, the membrane composition was modified with the addition of Sm0.2Ce0.8O1.9-delta (SDC) at varying wt.% to improve the membranes mechanical stability. A newly developed method to evaluate the oxygen permeation performance of OTMs is also presented by fitting OTM's oxygen permeability to the methane fraction in the sweeping gas composition. The fitted data is used to estimate the overall performance and size of OTMs utilized for the application of oxy-fuel combustion. The findings from this

  6. Peripheral lymphocyte subset variation predicts prostate cancer carbon ion radiotherapy outcomes

    Science.gov (United States)

    Shi, Ze-Liang; Li, Bing-Xin; Wu, Xian-Wei; Li, Ping; Zhang, Qing; Wei, Xun-Bin; Fu, Shen

    2016-01-01

    The immune system plays a complementary role in the cytotoxic activity of radiotherapy. Here, we examined changes in immune cell subsets after heavy ion therapy for prostate cancer. The lymphocyte counts were compared with acute radiotherapy-related toxicity, defined according to the Common Terminology Criteria for Adverse Events, and short-term local efficacy, defined based on prostate-specific antigen concentrations. Confirmed prostate cancer patients who had not received previous radiotherapy were administered carbon ion radiotherapy (CIR) in daily fractions of 2.74 GyE with a total dose of 63-66 GyE. Lymphocyte subset counts were investigated before, during and after radiotherapy, and at a 1 month follow-up. Most notable among our findings, the CD4/CD8 ratio and CD19+ cell counts were consistently higher in patients with a complete response (CR) or partial response (PR) to CIR than in those classified in the stable disease (SD) group (P<0.05 for both). But CD3+ and CD8+ cell counts were lower in the CR and PR groups than in the SD group. These results indicate that variations in peripheral lymphocyte subpopulations are predictive of outcome after CIR for prostate cancer. PMID:27029063

  7. The human Vδ2+ T-cell compartment comprises distinct innate-like Vγ9+ and adaptive Vγ9- subsets.

    Science.gov (United States)

    Davey, Martin S; Willcox, Carrie R; Hunter, Stuart; Kasatskaya, Sofya A; Remmerswaal, Ester B M; Salim, Mahboob; Mohammed, Fiyaz; Bemelman, Frederike J; Chudakov, Dmitriy M; Oo, Ye H; Willcox, Benjamin E

    2018-05-02

    Vδ2 + T cells form the predominant human γδ T-cell population in peripheral blood and mediate T-cell receptor (TCR)-dependent anti-microbial and anti-tumour immunity. Here we show that the Vδ2 + compartment comprises both innate-like and adaptive subsets. Vγ9 + Vδ2 + T cells display semi-invariant TCR repertoires, featuring public Vγ9 TCR sequences equivalent in cord and adult blood. By contrast, we also identify a separate, Vγ9 - Vδ2 + T-cell subset that typically has a CD27 hi CCR7 + CD28 + IL-7Rα + naive-like phenotype and a diverse TCR repertoire, however in response to viral infection, undergoes clonal expansion and differentiation to a CD27 lo CD45RA + CX 3 CR1 + granzymeA/B + effector phenotype. Consistent with a function in solid tissue immunosurveillance, we detect human intrahepatic Vγ9 - Vδ2 + T cells featuring dominant clonal expansions and an effector phenotype. These findings redefine human γδ T-cell subsets by delineating the Vδ2 + T-cell compartment into innate-like (Vγ9 + ) and adaptive (Vγ9 - ) subsets, which have distinct functions in microbial immunosurveillance.

  8. Residual oxygen time model for oxygen partial pressure near 130 kPa (1.3 atm).

    Science.gov (United States)

    Shykoff, Barbara E

    2015-01-01

    A two-part residual oxygen time model predicts the probability of detectible pulmonary oxygen toxicity P(P[O2tox]) after dives with oxygen partial pressure (PO2) approximately 130 kPa, and provides a tool to plan dive series with selected risk of P[O2tox]. Data suggest that pulmonary oxygen injury at this PO2 is additive between dives. Recovery begins after a delay and continues during any following dive. A logistic relation expresses P(P[O2tox]) as a function of dive duration (T(dur)) [hours]: P(P[O2tox]) = 100/[1+exp (3.586-0.49 x T(dur))] This expression maps T(dur) to P(P[O2tox]) or, in the linear mid-portion of the curve, P(P[O2tox]) usefully to T(dur). For multiple dives or during recovery, it maps to an equivalent dive duration, T(eq). T(eq) was found after second dives of duration T(dur 2). Residual time from the first dive t(r) = T(eq) - T(dur2). With known t(r), t and T(dur) a recovery model was fitted. t(r) = T(dur) x exp [-k x((t-5)/T(dur)2], where t = t - 5 hours, k = 0.149 for resting, and 0.047 for exercising divers, and t represents time after surfacing. The fits were assessed for 1,352 man-dives. Standard deviations of the residuals were 8.5% and 18.3% probability for resting or exercise dives, respectively.

  9. Different spectra of recurrent gene mutations in subsets of chronic lymphocytic leukemia harboring stereotyped B-cell receptors

    DEFF Research Database (Denmark)

    Sutton, Lesley-Ann; Young, Emma; Baliakas, Panagiotis

    2016-01-01

    We report on markedly different frequencies of genetic lesions within subsets of chronic lymphocytic leukemia patients carrying mutated or unmutated stereotyped B-cell receptor immunoglobulins in the largest cohort (n=565) studied for this purpose. By combining data on recurrent gene mutations...... subsets implies that the mechanisms underlying clinical aggressiveness are not uniform, but rather support the existence of distinct genetic pathways of clonal evolution governed by a particular stereotyped B-cell receptor selecting a certain molecular lesion(s)....

  10. The formation of non-oxidic oxygen phases on Ru(0001). From the first stages of the oxygen take-up to oxidation

    International Nuclear Information System (INIS)

    Blume, R.

    2005-01-01

    K. With further increasing oxygen contents underneath the topmost ruthenium layer the bond of the chemisorbed oxygen is reduced leading to an additional desorption feature at a lower temperature of 950 K. The ''subsurface''phases formed that way can be considered as a precursor to the oxide formation. In an intermediate preparation range in between 550 and 600 K for very high oxygen exposures the formation of oxidic phases are observed whose spacial dimensions cannot be resolved with SPEM. The onset of oxide formation is characterized by the growth of RuO2(110) oxide domains in dependence of oxygen exposure and sample temperature. The areas in between the oxide domains do not spectroscopically resemble either the chemisorbed layer or the oxide. In fact they show the features of a strongly distorted and oxygen enriched surface. (orig.)

  11. Toll-like receptor activation reveals developmental reorganization and unmasks responder subsets of microglia

    NARCIS (Netherlands)

    Scheffel, Joerg; Regen, Tommy; Van Rossum, Denise; Seifert, Stefanie; Ribes, Sandra; Nau, Roland; Parsa, Roham; Harris, Robert A.; Boddeke, Hendrikus W. G. M.; Chuang, Han-Ning; Pukrop, Tobias; Wessels, Johannes T.; Juergens, Tanja; Merkler, Doron; Brueck, Wolfgang; Schnaars, Mareike; Simons, Mikael; Kettenmann, Helmut; Hanisch, Uwe-Karsten

    2012-01-01

    The sentinel and immune functions of microglia require rapid and appropriate reactions to infection and damage. Their Toll-like receptors (TLRs) sense both as threats. However, whether activated microglia mount uniform responses or whether subsets conduct selective tasks is unknown. We demonstrate

  12. Influence of nitrogen oxides NO and NO2 on singlet delta oxygen production in pulsed discharge

    International Nuclear Information System (INIS)

    Ionin, A A; Klimachev, Yu M; Kozlov, A Yu; Kotkov, A A; Rulev, O A; Seleznev, L V; Sinitsyn, D V; Vagin, N P; Yuryshev, N N; Kochetov, I V; Napartovich, A P

    2009-01-01

    The influence of nitrogen oxides NO and NO 2 on the specific input energy (SIE) and the time behaviour of singlet delta oxygen (SDO) luminescence excited by a pulsed e-beam sustained discharge in oxygen were experimentally and theoretically studied. NO and NO 2 addition into oxygen results in a small increase and decrease in the SIE, respectively, the latter being connected with a large energy of electron affinity to NO 2 . The addition of 0.1-0.3% nitrogen oxides was experimentally and theoretically demonstrated to result in a notable enhancement of the SDO lifetime, which is related to a decrease in the atomic oxygen concentration in afterglow. It was experimentally demonstrated that to get a high SDO concentration at the gas pressure 30-60 Torr for a time interval of less than ∼0.5 s one needs to add not less than 0.2% nitrogen oxides into oxygen. The temperature dependence of the relaxation constant for SDO quenching by unexcited oxygen was estimated by using experimental data on the time behaviour of SDO luminescence.

  13. Low oxygen level increases proliferation and metabolic changes in bovine granulosa cells.

    Science.gov (United States)

    Shiratsuki, Shogo; Hara, Tomotaka; Munakata, Yasuhisa; Shirasuna, Koumei; Kuwayama, Takehito; Iwata, Hisataka

    2016-12-05

    The present study addresses molecular backgrounds underlying low oxygen induced metabolic changes and 1.2-fold change in bovine granulosa cell (GCs) proliferation. RNA-seq revealed that low oxygen (5%) upregulated genes associated with HIF-1 and glycolysis and downregulated genes associated with mitochondrial respiration than that in high oxygen level (21%). Low oxygen level induced high glycolytic activity and low mitochondrial function and biogenesis. Low oxygen level enhanced GC proliferation with high expression levels of HIF-1, VEGF, AKT, mTOR, and S6RP, whereas addition of anti-VEGF antibody decreased cellular proliferation with low phosphorylated AKT and mTOR expression levels. Low oxygen level reduced SIRT1, whereas activation of SIRT1 by resveratrol increased mitochondrial replication and decreased cellular proliferation with reduction of phosphorylated mTOR. These results suggest that low oxygen level stimulates the HIF1-VEGF-AKT-mTOR pathway and up-regulates glycolysis, which contributes to GC proliferation, and downregulation of SIRT1 contributes to hypoxia-associated reduction of mitochondria and cellular proliferation. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  14. Subset simulation for structural reliability sensitivity analysis

    International Nuclear Information System (INIS)

    Song Shufang; Lu Zhenzhou; Qiao Hongwei

    2009-01-01

    Based on two procedures for efficiently generating conditional samples, i.e. Markov chain Monte Carlo (MCMC) simulation and importance sampling (IS), two reliability sensitivity (RS) algorithms are presented. On the basis of reliability analysis of Subset simulation (Subsim), the RS of the failure probability with respect to the distribution parameter of the basic variable is transformed as a set of RS of conditional failure probabilities with respect to the distribution parameter of the basic variable. By use of the conditional samples generated by MCMC simulation and IS, procedures are established to estimate the RS of the conditional failure probabilities. The formulae of the RS estimator, its variance and its coefficient of variation are derived in detail. The results of the illustrations show high efficiency and high precision of the presented algorithms, and it is suitable for highly nonlinear limit state equation and structural system with single and multiple failure modes

  15. Reaeration of oxygen in shallow, macrophyte rich streams. 1

    International Nuclear Information System (INIS)

    Thyssen, N.; Erlandsen, M.; Jeppesen, E.

    1987-01-01

    The rate coefficient K 2 for the exchange of oxygen between flowing water and the atmosphere (reaeration) has been studied in six Danish streams covering a relatively wide range of hydraulic conditions, pollutional loading, and macrophyte abundance. 103 K 2 measurements were performed in 1978-85. 82 measurements were obtained applying 5 different indirect methods all balancing the sources and sinks of stream dissolved oxygen under conditions of normal operation of the system (3 methods) and under artificial depletion of the oxygen concentration of the stream water by addition of sodium sulfite (2 methods). 21 K 2 values were determined directly applying the gaseous tracer 85 Kr for reaeration. Guidelines for selecting a proper method to determine K 2 knowing macrophyte biomass and loading characteristics of the particular stream are provided. (author)

  16. Promoting effect of oxygen for hydrogenation of butadiene over Ni/sub 2/P catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Nozaki, F.; Kitoh, T.; Sodesawa, T.

    1980-04-01

    When 0-10 mm Hg of oxygen were added to the reaction of 75 mm Hg butadiene and 225 mm Hg hydrogen over dinickel phosphide in a closed circulation system at 40/sup 0/C, increasing amounts of oxygen caused increasing lengths of induction periods followed by hydrogenation at reaction rates which had a maximum at 3 mm Hg oxygen. This maximum rate was about six times higher than the rate without oxygen addition. Adsorption, temperature-programed desorption, IR spectroscopy, and the product distribution of butadiene deuteration showed that two types of oxygen adsorbed on the dinickel phosphide catalyst; molecular oxygen on nickel, which desorbed on evacuation below 50/sup 0/C and which could be displaced by butadiene, was responsible for the induction period; molecular oxygen on phosphorus atoms, which promoted hydrogen adsorption, was responsible for the increased hydrogenation rate.

  17. Effects of Hyperoxia on Oxygen-Related Inflammation with a Focus on Obesity

    Directory of Open Access Journals (Sweden)

    Pedro González-Muniesa

    2016-01-01

    Full Text Available Several studies have shown a pathological oxygenation (hypoxia/hyperoxia on the adipose tissue in obese subjects. Additionally, the excess of body weight is often accompanied by a state of chronic low-degree inflammation. The inflammation phenomenon is a complex biological response mounted by tissues to combat injurious stimuli in order to maintain cell homeostasis. Furthermore, it is believed that the abnormal oxygen partial pressure occurring in adipose tissue is involved in triggering inflammatory processes. In this context, oxygen is used in modern medicine as a treatment for several diseases with inflammatory components. Thus, hyperbaric oxygenation has demonstrated beneficial effects, apart from improving local tissue oxygenation, on promoting angiogenesis, wound healing, providing neuroprotection, facilitating glucose uptake, appetite, and others. Nevertheless, an excessive hyperoxia exposure can lead to deleterious effects such as oxidative stress, pulmonary edema, and maybe inflammation. Interestingly, some of these favorable outcomes occur under high and low oxygen concentrations. Hereby, we review a potential therapeutic approach to the management of obesity as well as the oxygen-related inflammation accompanying expanded adipose tissue, based on elevated oxygen concentrations. To conclude, we highlight at the end of this review some areas that need further clarification.

  18. Tissue-specific Differences in Immune Cell Subsets Located in the Naso-oropharyngeal-associated Lymphoid Tissues.

    Science.gov (United States)

    Bankvall, M; Jontell, M; Wold, A; Östman, S

    2018-01-01

    Defining the immune cells within the naso-oropharyngeal-associated lymphoid tissues would promote the development of efficient orally and nasally delivered immunotherapies. The aim was to compare murine antigen-presenting cells (APCs) and T cell subsets in the nose-associated lymphoid tissues (NALT), cervical lymph nodes (CLN), mesenteric lymph nodes (MLN) and peripheral lymph nodes (PLN) using flow cytometry and in vitro proliferation assays. Overall, the NALT contained a higher proportion of APCs and a lower proportion of T cells compared to the CLN, MLN and PLN. The APCs of the NALT more often belonged to the CD11c + CD11b + and the CD11c neg CD11b + subsets as compared to the other sites. Both of these APC populations showed little sign of activation, that is low expression of the markers CD40, CD86 and IAd. Instead, the APCs of the NALT more often co-expressed CX3CR1 and CD206, markers associated with a tolerogenic function. No increase in the proportion of regulatory T cells was observed in the NALT. Instead, the T cells frequently exhibited a memory/effector phenotype, expressing the homing markers α4β7, CCR4 and CCR9, but rarely the naïve phenotype cell surface marker CD45RB. In contrast, the T cells at the other sites were mostly of the naïve phenotype. In addition, cells from the NALT did not proliferate upon in vitro stimulation with Con A, whereas the cells from the other sites did. Taken together, these results suggest that the NALT is primarily an effector site rather than one for activation and differentiation, despite it being regarded as a site of induction. © 2017 The Foundation for the Scandinavian Journal of Immunology.

  19. Oxygen permeation through oxygen ion oxide-noble metal dual phase composites

    NARCIS (Netherlands)

    Chen, C.S.; Chen, C.S.; Kruidhof, H.; Bouwmeester, Henricus J.M.; Verweij, H.; Burggraaf, Anthonie; Burggraaf, A.J.

    1996-01-01

    Oxygen permeation behaviour of three composites, yttria-stabilized zirconia-palladium, erbia-stabilized bismuth oxidenoble metal (silver, gold) was studied. Oxygen permeation measurements were performed under controlled oxygen pressure gradients at elevated temperatures. Air was supplied at one side

  20. HIV infection and aging: enhanced Interferon- and Tumor Necrosis Factor-alpha production by the CD8+ CD28- T subset

    Directory of Open Access Journals (Sweden)

    Colón-Martinez Sol

    2001-10-01

    Full Text Available Abstract Background T cells from HIV+ and aged individuals show parallels in terms of suppressed proliferative activity and interleukin-2 (I1-2 production and an increased number of CD8+ CD28- T cells. In order to compare cytokine production from T cells from these two states, CD4+ and CD8+ T cells from HIV+ aged, and normal young donors (controls were monitored for cytokine production by flow cytometry, quantitative PCR and ELISA upon activation by PMA and anti-CD3. In addition, the CD8+ T cell subsets CD28+ and CD28- from the HIV+ and the aged groups were evaluated for cytokine production by flow cytometry, and compared with those from young controls. Results Flow cytometric analysis indicated that CD8+ T cells from both HIV+ and aged donors showed an increase of approximately 2–3 fold over controls in percentage of cells producing inflammatory cytokines IFN-γ and TNF-α. Similar analysis also revealed that the production of interleukins-4,6 and 10, production was very low (1–2% of cells and unchanged in these cells. Quantitative PCR also showed a substantial increase (4–5 fold in IFN-γ and TNF-α mRNA from HIV+ and aged CD8+ T cells, as did ELISA for secreted IFN-γ and TNF-α (2.3–4 fold. Flow cytometric analysis showed that the CD8+ CD28- T cell subset accounts for approximately 80–86% of the IFN-γ and TNF-α production from the CD8+ subset in the aged and HIV+ states. The CD4+ T cell, while not significantly changed in the HIV+ or aged states in terms of IFN-γ production, showed a small but significant increase in TNF-α production in both states. Conclusions Our data appear compatible with physiologic conditions existing in HIV+ and aged individuals, i.e. elevated serum levels and elevated CD8+ T cell production of IFN-γ and TNF-α. Thus, the capacity for increased production of cytokines IFN-γ and TNF-α in the aged individual by the dominant CD8+ CD28- subset may have a profound influence on the clinical state by

  1. Oxygen vacancies in oxides studied by annihilation of mono-energetic positrons

    Energy Technology Data Exchange (ETDEWEB)

    Hugenschmidt, Christoph; Pikart, Philip [ZWE FRM II, Technische Universitaet Muenchen, Lichtenbergstrasse 1, 85747 Garching (Germany); Physik-Department E21, Technische Universitaet Muenchen, James-Franck-Strasse, 85748 Garching (Germany); Schreckenbach, Klaus [Physik-Department E21, Technische Universitaet Muenchen, James-Franck-Strasse, 85748 Garching (Germany)

    2009-07-01

    Oxygen vacancies play a fundamental role for the material properties of various oxides, e.g. charge carrier density in high-Tc superconductors, magnetic properties of diluted magnetic semiconductors or paramagnetic properties of SiO{sub 2}. In this study, open volume defects in (metal) oxides are investigated by Doppler-broadening spectroscopy (DBS) of the positron annihilation. More detailed information about the chemical surrounding at the positron annihilation site is gained by additional coincident DBS experiments, where a signature of positrons annihilating with electrons from oxygen is observed. The mono-energetic positron beam at NEPOMUC was used which allows depth dependent measurements, and hence the investigation of thin oxide layers. Recent results for metallic oxides such as ZnO are presented and compared with various non-metallic oxides such as amorphous and crystalline SiO{sub 2}, oxygen terminated Si-surface, and ice. The role of neutral and charged oxygen vacancies and the application of the positron annihilation technique to study oxygen vacancies will be discussed.

  2. Solubility on compact subsets for differential equations with real principal pencil of symbols

    International Nuclear Information System (INIS)

    Shananin, N A

    2006-01-01

    The central result is a theorem on the solubility on compact subsets for differential equations of quasiprincipal type with real principal pencil of symbols. The proof is based on the analysis of the microlocal structure of the singularities of solutions of equations in this class.

  3. The oxygen effect and adaptive response of cells. Report 3. Simulation of respiratory oxygenation and oxygen permeability of cells

    International Nuclear Information System (INIS)

    Ehpshtejn, I.M.

    1978-01-01

    Variations in the oxygen concentration in extracellural [O 2 ] 0 and intracellular [Osub(2)]sub(i) media of cells small in size (d = 2 ] 0 - t-curves). It is shown that the Value of [Osub(2)]sub(i) may be expressed by four variants of its functional dependence: (a) on enzymic reaction of oxygen consumption, (b) on the order of reaction with respect to oxygen, (c) on physiological parameters of cells, and (d) on characteristic oxygen concentrations in the system. Items (c) and (d) are based on the postulated diffusion-kinetic model of oxygen consumption by an idealized cell of small size that consists of a drop of homogenous solution of the respiratory enzyme which is characterized by an equivalent Michaelis constant. The drop is enveloped in a uniform membrane that possesses a definite diffuse resistance to oxygen

  4. Cyanobacterial Oxygenic Photosynthesis is Protected by Flavodiiron Proteins

    Directory of Open Access Journals (Sweden)

    Yagut Allahverdiyeva

    2015-03-01

    Full Text Available Flavodiiron proteins (FDPs, also called flavoproteins, Flvs are modular enzymes widely present in Bacteria and Archaea. The evolution of cyanobacteria and oxygenic photosynthesis occurred in concert with the modulation of typical bacterial FDPs. Present cyanobacterial FDPs are composed of three domains, the β-lactamase-like, flavodoxin-like and flavin-reductase like domains. Cyanobacterial FDPs function as hetero- and homodimers and are involved in the regulation of photosynthetic electron transport. Whilst Flv2 and Flv4 proteins are limited to specific cyanobacterial species (β-cyanobacteria and function in photoprotection of Photosystem II, Flv1 and Flv3 proteins, functioning in the “Mehler-like” reaction and safeguarding Photosystem I under fluctuating light conditions, occur in nearly all cyanobacteria and additionally in green algae, mosses and lycophytes. Filamentous cyanobacteria have additional FDPs in heterocyst cells, ensuring a microaerobic environment for the function of the nitrogenase enzyme under the light. Here, the evolution, occurrence and functional mechanisms of various FDPs in oxygenic photosynthetic organisms are discussed.

  5. Increased hepatic Th2 and Treg subsets are associated with biliary fibrosis in different strains of mice caused by Clonorchis sinensis.

    Directory of Open Access Journals (Sweden)

    Bei-Bei Zhang

    Full Text Available Previous studies showed that CD4+T cells responses might be involved in the process of biliary fibrosis. However, the underlying mechanism resulting in biliary fibrosis caused by Clonorchis sinensis remains not yet fully elucidated. The objectives of the present study were to investigate the different profiles of hepatic CD4+T cell subsets (Th1, Th2, Th17 and Treg cells and their possible roles in the biliary fibrosis of different strains of mice (C57BL/6, BALB/c and FVB mice induced by C. sinensis infection. C57BL/6, BALB/c and FVB mice were orally gavaged with 45 metacercariae. All mice were sacrificed on 28 days post infection in deep anesthesia conditions. The leukocytes in the liver were separated to examine CD4+T cell subsets by flow cytometry and the left lobe of liver was used to observe pathological changes, collagen depositions and the concentrations of hydroxyproline. The most serious cystic and fibrotic changes appeared in FVB infected mice indicated by gross observation, Masson's trichrome staining and hydroxyproline content detection. In contrast to C57BL/6 infected mice, diffuse nodules and more intensive fibrosis were observed in the BALB/c infected mice. No differences of the hepatic Th1 subset and Th17 subset were found among the three strains, but the hepatic Th2 and Treg cells and their relative cytokines were dramatically increased in the BALB/c and FVB infected groups compared with the C57BL/6 infected group (P<0.01. Importantly, increased Th2 subset and Treg subset all positively correlated with hydroxyproline contents (P<0.01. This result for the first time implied that the increased hepatic Th2 and Treg cell subsets were likely to play potential roles in the formation of biliary fibrosis in C. sinensis-infected mice.

  6. Organic hydrogen peroxide-driven low charge potentials for high-performance lithium-oxygen batteries with carbon cathodes

    Science.gov (United States)

    Wu, Shichao; Qiao, Yu; Yang, Sixie; Ishida, Masayoshi; He, Ping; Zhou, Haoshen

    2017-06-01

    Reducing the high charge potential is a crucial concern in advancing the performance of lithium-oxygen batteries. Here, for water-containing lithium-oxygen batteries with lithium hydroxide products, we find that a hydrogen peroxide aqueous solution added in the electrolyte can effectively promote the decomposition of lithium hydroxide compounds at the ultralow charge potential on a catalyst-free Ketjen Black-based cathode. Furthermore, for non-aqueous lithium-oxygen batteries with lithium peroxide products, we introduce a urea hydrogen peroxide, chelating hydrogen peroxide without any water in the organic, as an electrolyte additive in lithium-oxygen batteries with a lithium metal anode and succeed in the realization of the low charge potential of ~3.26 V, which is among the best levels reported. In addition, the undesired water generally accompanying hydrogen peroxide solutions is circumvented to protect the lithium metal anode and ensure good battery cycling stability. Our results should provide illuminating insights into approaches to enhancing lithium-oxygen batteries.

  7. Proterozoic atmospheric oxygen

    DEFF Research Database (Denmark)

    Canfield, Donald Eugene

    2014-01-01

    This article is concerned with the evolution of atmospheric oxygen concentrations through the Proterozoic Eon. In particular, this article will seek to place the history of atmospheric oxygenation through the Proterozoic Eon in the context of the evolving physical environment including the history...... of continental growth and volcanic outgassing, as well as biogeochemical processing of elements within the oceans. The author will seek to explore constraints on the history of oxygenation and understand which processes have regulated oxygen through this eon....

  8. Work function of oxygen exposed lead and lead/indium alloy films

    International Nuclear Information System (INIS)

    Gundlach, K.H.; Hellemann, H.P.; Hoelzl, J.

    1982-01-01

    The effect of indium in superconducting tunnel junctions with lead/indium alloy base electrodes is investigated by measuring the vacuum work function of lead, indium, and lead/indium alloy films. It is found that the anomalous decrease of the work function of lead upon exposure to oxygen, explained by the penetration of oxygen into the inner surface of the lead film, is reversed into a slight increase in work function when some indium is added to the lead. This result indicates that the addition of indium provides a protection by suppressing the penetration of oxygen (and probably other gases) into the interior of the thin film

  9. Effect of oxygen content on n-heptane auto-ignition characteristics in a HCCI engine

    International Nuclear Information System (INIS)

    Wu, Zhijun; Kang, Zhe; Deng, Jun; Hu, Zongjie; Li, Liguang

    2016-01-01

    Highlights: • n-Heptane HCCI combustion under air and oxygen intake was compared. • n-Heptane auto-ignition postponed due to higher specific heat capacity as oxygen increase. • The increment of heat release fraction during low temperature reaction is studied. • Oxygen enrichment lead to suppressed negative temperature coefficient. • The mechanism of low temperature reaction enhancement as oxygen increase is investigated. - Abstract: To take maximum advantage of the high efficiency of homogeneous charge compression ignition combustion mode and internal combustion Rankine cycle concept, in this study, the n-heptane auto-ignition characteristics have been investigated using a compression ignition internal combustion Rankine cycle engine test bench and a zero-dimensional thermodynamic model coupled with a detailed kinetic model. The n-heptane auto-ignition process shows that under both air and oxygen intake, a typical two-stage combustion in which oxygen enrichment has very minor effects on the n-heptane high temperature reaction. The higher specific heat capacity of oxygen compared with nitrogen leads to an overall increased specific heat capacity, which lowers the in-cylinder temperature during compression stroke, thereby delaying the low temperature reaction initial timing. The higher oxygen content also improves the H-atom abstraction, first O_2 addition, second O_2 addition and peroxyalkylhydroperoxide isomerization, thereby improving the overall reaction rate and the heat release fraction of low temperature reaction. As a result, the in-cylinder temperature at the end of low temperature reaction also increases, thereby shortening significantly the negative temperature coefficient duration compared with a combustion cycle using air as oxidizer.

  10. Oxygen respiration rates of benthic foraminifera as measured with oxygen microsensors

    DEFF Research Database (Denmark)

    Geslin, E.; Risgaard-Petersen, N.; Lombard, Fabien

    2011-01-01

    of the foraminiferal specimens. The results show a wide range of oxygen respiration rates for the different species (from 0.09 to 5.27 nl cell−1 h−1) and a clear correlation with foraminiferal biovolume showed by the power law relationship: R = 3.98 10−3 BioVol0.88 where the oxygen respiration rate (R) is expressed......Oxygen respiration rates of benthic foraminifera are still badly known, mainly because they are difficult to measure. Oxygen respiration rates of seventeen species of benthic foraminifera were measured using microelectrodes and calculated on the basis of the oxygen fluxes measured in the vicinity...... groups (nematodes, copepods, ostracods, ciliates and flagellates) suggests that benthic foraminifera have a lower oxygen respiration rates per unit biovolume. The total contribution of benthic foraminifera to the aerobic mineralisation of organic matter is estimated for the studied areas. The results...

  11. Experimental and theoretical studies of nuclear generation of ozone from oxygen and oxygen--sulfur hexafluoride mixtures

    International Nuclear Information System (INIS)

    Elsayed-Ali, H.E.; Miley, G.H.

    1986-01-01

    A series of experimental measurements of the yield of O 3 in nuclear-induced O 2 and O 2 -SF 6 discharges are reported. The discharges were created by bombardment with energetic particles from the 10 B(n,α) 7 Li reaction. Continuous irradiation at dose rates of 10 15 --10 17 eV cm -3 s -1 and pulsed irradiation (--10 ms FWHM) at a peak dose rate of --10 20 eV cm -3 s -1 were conducted. At the lower dose rates, the addition of SF 6 generally increased the ozone yield due to the slowing of ozone destruction by negative oxygen and ozone ions. In contrast, at the high dose rates, the ozone concentration decreased due to SF 6 suppression of atomic oxygen formation by ion--ion recombination. A numerical model was developed and tested against experimental conditions. This model indicates that the steady-state ozone concentration was limited by the reaction O - 3 +O 3 →2O 2 +O - 2 with a rate coefficient of --1 x 10 -12 cm 3 s -1 . In addition to dose rate effects, pressure and temperature effects on ozone production are discussed and methods for increasing the ozone yield are suggested

  12. Experimental and theoretical studies of nuclear generation of ozone from oxygen and oxygen-sulfur hexafluoride mixtures

    Science.gov (United States)

    Elsayed-Ali, H. E.; Miley, G. H.

    1986-08-01

    A series of experimental measurements of the yield of O3 in nuclear-induced O2 and O2-SF6 discharges are reported. The discharges were created by bombardment with energetic particles from the 10B(n,α)7Li reaction. Continuous irradiation at dose rates of 1015-1017 eV cm-3 s-1 and pulsed irradiation (˜10 ms FWHM) at a peak dose rate of ˜1020 eV cm-3 s-1 were conducted. At the lower dose rates, the addition of SF6 generally increased the ozone yield due to the slowing of ozone destruction by negative oxygen and ozone ions. In contrast, at the high dose rates, the ozone concentration decreased due to SF6 suppression of atomic oxygen formation by ion-ion recombination. A numerical model was developed and tested against experimental conditions. This model indicates that the steady-state ozone concentration was limited by the reaction O-3+O3→2O2+O-2 with a rate coefficient of ˜1×10-12 cm3 s-1. In addition to dose rate effects, pressure and temperature effects on ozone production are discussed and methods for increasing the ozone yield are suggested.

  13. A model for oxygen conservation associated with titration during pediatric oxygen therapy.

    Directory of Open Access Journals (Sweden)

    Grace Wu

    Full Text Available Continuous oxygen treatment is essential for managing children with hypoxemia, but access to oxygen in low-resource countries remains problematic. Given the high burden of pneumonia in these countries and the fact that flow can be gradually reduced as therapy progresses, oxygen conservation through routine titration warrants exploration.To determine the amount of oxygen saved via titration during oxygen therapy for children with hypoxemic pneumonia.Based on published clinical data, we developed a model of oxygen flow rates needed to manage hypoxemia, assuming recommended flow rate at start of therapy, and comparing total oxygen used with routine titration every 3 minutes or once every 24 hours versus no titration.Titration every 3 minutes or every 24 hours provided oxygen savings estimated at 11.7% ± 5.1% and 8.1% ± 5.1% (average ± standard error of the mean, n = 3, respectively. For every 100 patients, 44 or 30 kiloliters would be saved-equivalent to 733 or 500 hours at 1 liter per minute.Ongoing titration can conserve oxygen, even performed once-daily. While clinical validation is necessary, these findings could provide incentive for the routine use of pulse oximeters for patient management, as well as further development of automated systems.

  14. Oxygen response of the wine yeast Saccharomyces cerevisiae EC1118 grown under carbon-sufficient, nitrogen-limited enological conditions.

    Science.gov (United States)

    Aceituno, Felipe F; Orellana, Marcelo; Torres, Jorge; Mendoza, Sebastián; Slater, Alex W; Melo, Francisco; Agosin, Eduardo

    2012-12-01

    Discrete additions of oxygen play a critical role in alcoholic fermentation. However, few studies have quantitated the fate of dissolved oxygen and its impact on wine yeast cell physiology under enological conditions. We simulated the range of dissolved oxygen concentrations that occur after a pump-over during the winemaking process by sparging nitrogen-limited continuous cultures with oxygen-nitrogen gaseous mixtures. When the dissolved oxygen concentration increased from 1.2 to 2.7 μM, yeast cells changed from a fully fermentative to a mixed respirofermentative metabolism. This transition is characterized by a switch in the operation of the tricarboxylic acid cycle (TCA) and an activation of NADH shuttling from the cytosol to mitochondria. Nevertheless, fermentative ethanol production remained the major cytosolic NADH sink under all oxygen conditions, suggesting that the limitation of mitochondrial NADH reoxidation is the major cause of the Crabtree effect. This is reinforced by the induction of several key respiratory genes by oxygen, despite the high sugar concentration, indicating that oxygen overrides glucose repression. Genes associated with other processes, such as proline uptake, cell wall remodeling, and oxidative stress, were also significantly affected by oxygen. The results of this study indicate that respiration is responsible for a substantial part of the oxygen response in yeast cells during alcoholic fermentation. This information will facilitate the development of temporal oxygen addition strategies to optimize yeast performance in industrial fermentations.

  15. Oxygen Transport Membranes

    Energy Technology Data Exchange (ETDEWEB)

    S. Bandopadhyay

    2008-08-30

    The focus of this research was to develop new membrane materials by synthesizing different compounds and determining their defect structures, crystallographic structures and electrical properties. In addition to measuring electrical conductivity, oxygen vacancy concentration was also evaluated using thermogravimetry, Neutron diffraction and Moessbauer Spectroscopy. The reducing conditions (CO{sub 2}/CO/H{sub 2} gas mixtures with steam) as encountered in a reactor environment can be expected to have significant influence on the mechanical properties of the oxides membranes. Various La based materials with and without Ti were selected as candidate membrane materials for OTM. The maximum electrical conductivity of LSF in air as a function of temperature was achieved at < 600 C and depends on the concentration of Sr (acceptor dopant). Oxygen occupancy in LSF was estimated using Neutron diffractometry and Moessbauer Spectroscopy by measuring magnetic moment changes depending on the Fe{sup 3+} and Fe{sup 4+} ratio. After extensive studies of candidate materials, lanthanum ferrites (LSF and LSFT) were selected as the favored materials for the oxygen transport membrane (OTM). LSF is a very good material for an OTM because of its high electronic and oxygen ionic conductivity if long term stability and mechanical strength are improved. LSFT not only exhibits p-type behavior in the high oxygen activity regime, but also has n-type conduction in reducing atmospheres. Higher concentrations of oxygen vacancies in the low oxygen activity regime may improve the performance of LSFT as an OTM. The hole concentration is related to the difference in the acceptor and donor concentration by the relation p = [Sr'{sub La}]-[Ti{sm_bullet}{sub Fe}]. The chemical formulation predicts that the hole concentration is, p = 0.8-0.45 or 0.35. Experimental measurements indicated that p is about {approx} 0.35. The activation energy of conduction is 0.2 eV which implies that LSCF conducts via the

  16. Analysis of T Cell Subsets in Adult Primary/Idiopathic Minimal Change Disease: A Pilot Study

    Directory of Open Access Journals (Sweden)

    Francisco Salcido-Ochoa

    2017-01-01

    Full Text Available Aim. To characterise infiltrating T cells in kidneys and circulating lymphocyte subsets of adult patients with primary/idiopathic minimal change disease. Methods. In a cohort of 9 adult patients with primary/idiopathic minimal change recruited consecutively at disease onset, we characterized (1 infiltrating immune cells in the kidneys using immunohistochemistry and (2 circulating lymphocyte subsets using flow cytometry. As an exploratory analysis, association of the numbers and percentages of both kidney-infiltrating immune cells and the circulating lymphocyte subsets with kidney outcomes including deterioration of kidney function and proteinuria, as well as time to complete clinical remission up to 48 months of follow-up, was investigated. Results. In the recruited patients with primary/idiopathic minimal change disease, we observed (a a dominance of infiltrating T helper 17 cells and cytotoxic cells, comprising cytotoxic T cells and natural killer cells, over Foxp3+ Treg cells in the renal interstitium; (b an increase in the circulating total CD8+ T cells in peripheral blood; and (c an association of some of these parameters with kidney function and proteinuria. Conclusions. In primary/idiopathic minimal change disease, a relative numerical dominance of effector over regulatory T cells can be observed in kidney tissue and peripheral blood. However, larger confirmatory studies are necessary.

  17. Toolsets for Airborne Data (TAD): Enhanced Airborne Data Merging Functionality through Spatial and Temporal Subsetting

    Science.gov (United States)

    Early, A. B.; Chen, G.; Beach, A. L., III; Northup, E. A.

    2016-12-01

    NASA has conducted airborne tropospheric chemistry studies for over three decades. These field campaigns have generated a great wealth of observations, including a wide range of the trace gases and aerosol properties. The Atmospheric Science Data Center (ASDC) at NASA Langley Research Center in Hampton Virginia originally developed the Toolsets for Airborne Data (TAD) web application in September 2013 to meet the user community needs for manipulating aircraft data for scientific research on climate change and air quality relevant issues. The analysis of airborne data typically requires data subsetting, which can be challenging and resource intensive for end users. In an effort to streamline this process, the TAD toolset enhancements will include new data subsetting features and updates to the current database model. These will include two subsetters: temporal and spatial, and vertical profile. The temporal and spatial subsetter will allow users to both focus on data from a specific location and/or time period. The vertical profile subsetter will retrieve data collected during an individual aircraft ascent or descent spiral. This effort will allow for the automation of the typically labor-intensive manual data subsetting process, which will provide users with data tailored to their specific research interests. The development of these enhancements will be discussed in this presentation.

  18. The tyrosine B10 hydroxyl is crucial for oxygen avidity of Ascaris hemoglobin.

    Science.gov (United States)

    Kloek, A P; Yang, J; Mathews, F S; Frieden, C; Goldberg, D E

    1994-01-28

    The parasitic nematode Ascaris suum has a gene encoding a two-domain hemoglobin with remarkable oxygen avidity. The strong interaction with oxygen is a consequence of a particularly slow oxygen off-rate. The single polypeptide chain consists of two domains, each of which can be expressed separately in Escherichia coli as a globin-like protein exhibiting oxygen binding characteristics comparable with the native molecule. Site-directed mutagenesis was performed on the gene segment encoding domain one. The E7 position, involved in forming a hydrogen bond with the liganded oxygen in vertebrate globins, is a glutamine in both Ascaris domains. Conversion of this residue to leucine or alanine produced a hemoglobin variant with an oxygen off-rate 5- or 60-fold faster than that of unaltered domain one. Replacement of the tyrosine B10 with either phenylalanine or leucine (as found in vertebrate globins) yielded hemoglobin mutants with oxygen off-rates 280- or 570-fold faster, approaching rates found with vertebrate myoglobins. The data suggest that the distal glutamine hydrogen bonds with the liganded oxygen and that the tyrosine B10 hydroxyl contributes an additional hydrogen bond that appears substantially responsible for the extreme oxygen avidity of Ascaris hemoglobin.

  19. Pivotal statistics for testing subsets of structural parameters in the IV Regression Model

    NARCIS (Netherlands)

    Kleibergen, F.R.

    2000-01-01

    We construct a novel statistic to test hypothezes on subsets of the structural parameters in anInstrumental Variables (IV) regression model. We derive the chi squared limiting distribution of thestatistic and show that it has a degrees of freedom parameter that is equal to the number ofstructural

  20. Oxygenated gasolines according to European specifications for quality and ecological clean gasoline

    International Nuclear Information System (INIS)

    Panovska, Vesna; Tomanovikj, Violeta

    1999-01-01

    With the phasing out of lead additives from gasoline, the interest for oxygenates as a gasoline components grows up. However, since these materials are not hydrocarbons their behaviour in terms of blending differs from the gasoline which consists of hydrocarbons only. Therefore, it is important to explain their role in blending gasolines according to European specification for motor fuels. It is important to emphasize the oxygenate contribution in production more clean gasoline. In this paper, the oxygenate types and there basic specification features followed by manufacture, laboratory testing and blending specifications with refinery components is presented. (Author)

  1. 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.

  2. The beneficial role of rubble mound coastal structures on seawater oxygenation

    Directory of Open Access Journals (Sweden)

    E. I. Daniil

    2000-10-01

    Full Text Available The beneficial role of rubble mound coastal structures on oxygenation under the effect of waves is discussed, based on analytical considerations and experimental data from laboratory experiments with permeable and impermeable structures. Significant oxygenation of the wave-protected area was observed as a result of horizontal transport through the permeable structure. A two-cell model describing the transport of dissolved oxygen (DO near a rubble mound breakwater structure was developed and used for the determination of the oxygen transfer coefficients from the experimental data. Oxygen transfer through the air–water interface is considered a source term in the transport equation and the oxygen flux through the structure is taken into account. The mass transport equations for both sides of the structure are solved analytically in terms of time evolution of DO concentration. The behaviour of the solution is illustrated for three different characteristic cases of initial conditions. The oxygen transfer through the air-water interface in the wave-influenced area increases the DO content in the area; the resulting oxygen flux through the structure is discussed. The analytical results depend on the initial conditions, the oxygen transfer coefficient and the exchange flow rate through the structure. Experiments with impermeable structures show that air water oxygen transfer in the harbour area is negligible in the absence of waves. In addition the ratio of the horizontal DO flux to the vertical flux into the seaward side tends towards a constant value, independent of the initial conditions.Key words: Oceanography: physical (air-sea interactions; surface waves and tides

  3. The Complex Transcriptional Response of Acaryochloris marina to Different Oxygen Levels

    Directory of Open Access Journals (Sweden)

    Miguel A. Hernández-Prieto

    2017-02-01

    Full Text Available Ancient oxygenic photosynthetic prokaryotes produced oxygen as a waste product, but existed for a long time under an oxygen-free (anoxic atmosphere, before an oxic atmosphere emerged. The change in oxygen levels in the atmosphere influenced the chemistry and structure of many enzymes that contained prosthetic groups that were inactivated by oxygen. In the genome of Acaryochloris marina, multiple gene copies exist for proteins that are normally encoded by a single gene copy in other cyanobacteria. Using high throughput RNA sequencing to profile transcriptome responses from cells grown under microoxic and hyperoxic conditions, we detected 8446 transcripts out of the 8462 annotated genes in the Cyanobase database. Two-thirds of the 50 most abundant transcripts are key proteins in photosynthesis. Microoxic conditions negatively affected the levels of expression of genes encoding photosynthetic complexes, with the exception of some subunits. In addition to the known regulation of the multiple copies of psbA, we detected a similar transcriptional pattern for psbJ and psbU, which might play a key role in the altered components of photosystem II. Furthermore, regulation of genes encoding proteins important for reactive oxygen species-scavenging is discussed at genome level, including, for the first time, specific small RNAs having possible regulatory roles under varying oxygen levels.

  4. The Complex Transcriptional Response of Acaryochloris marina to Different Oxygen Levels

    Science.gov (United States)

    Hernández-Prieto, Miguel A.; Lin, Yuankui; Chen, Min

    2016-01-01

    Ancient oxygenic photosynthetic prokaryotes produced oxygen as a waste product, but existed for a long time under an oxygen-free (anoxic) atmosphere, before an oxic atmosphere emerged. The change in oxygen levels in the atmosphere influenced the chemistry and structure of many enzymes that contained prosthetic groups that were inactivated by oxygen. In the genome of Acaryochloris marina, multiple gene copies exist for proteins that are normally encoded by a single gene copy in other cyanobacteria. Using high throughput RNA sequencing to profile transcriptome responses from cells grown under microoxic and hyperoxic conditions, we detected 8446 transcripts out of the 8462 annotated genes in the Cyanobase database. Two-thirds of the 50 most abundant transcripts are key proteins in photosynthesis. Microoxic conditions negatively affected the levels of expression of genes encoding photosynthetic complexes, with the exception of some subunits. In addition to the known regulation of the multiple copies of psbA, we detected a similar transcriptional pattern for psbJ and psbU, which might play a key role in the altered components of photosystem II. Furthermore, regulation of genes encoding proteins important for reactive oxygen species-scavenging is discussed at genome level, including, for the first time, specific small RNAs having possible regulatory roles under varying oxygen levels. PMID:27974439

  5. Hydrodeoxygenation of aliphatic and aromatic oxygenates on sulphided catalysts for production of second generation biofuels

    Energy Technology Data Exchange (ETDEWEB)

    Senol, O.I.

    2007-07-01

    desulphurisation and coking. Water inhibited the HDO, but the addition of H{sub 2}S effectively eliminated the inhibition. The addition of H{sub 2}S enhanced HDO and stabilised the selectivities but did not prevent deactivation of the catalysts. The effect of H{sub 2}S was explained in terms of promotion of the acid-catalysed reactions due to enhanced catalyst acidity. Water and the sulphiding agents added to the HDO feed suppressed hydrogenation reactions on the NiMo catalyst but did not affect them on the CoMo catalyst. The addition of H{sub 2}S resulted in less hydrogen consumption and coke formation than the addition of CS{sub 2}, but the product distribution was shifted such that the carbon efficiency decreased. It was concluded that, for the HDO of aliphatic oxygenates, H{sub 2}S was superior to CS{sub 2} as a sulphiding agent. The HDO of phenol, used as a model aromatic oxygenate, produced aromatic and alicyclic hydrocarbons in parallel routes in which the primary reactions were direct hydrogenolysis and hydrogenation, respectively. The addition of H{sub 2}S on both catalysts inhibited the HDO due to competitive adsorption of phenol and H{sub 2}S, and affected the hydrogenation reactions in the same way as in the HDO of aliphatic oxygenates. The opposite effects of H{sub 2}S on the HDO of aliphatic and aromatic oxygenates were attributed to the different reaction mechanisms for oxygen elimination (dehydration, hydrolysis, elimination and direct hydrogenolysis reactions). The different molecular and electronic structures of the aliphatic and aromatic oxygenates are likely the reason for the different reaction mechanisms. Under the identical conditions, phenol was less reactive than aliphatic oxygenates on the sulphided catalysts. In contrast to the situation in the HDO of aliphatic oxygenates, the NiMo catalyst was less active for the HDO of phenol than was the CoMo catalyst. This work illustrates that the composition of biofuels determines the overall performance of the HDO

  6. Atomic Oxygen Erosion Yield Dependence Upon Texture Development in Polymers

    Science.gov (United States)

    Banks, Bruce A.; Loftus, Ryan J.; Miller, Sharon K.

    2016-01-01

    The atomic oxygen erosion yield (volume of a polymer that is lost due to oxidation per incident atom) of polymers is typically assumed to be reasonably constant with increasing fluence. However polymers containing ash or inorganic pigments, tend to have erosion yields that decrease with fluence due to an increasing presence of protective particles on the polymer surface. This paper investigates two additional possible causes for erosion yields of polymers that are dependent upon atomic oxygen. These are the development of surface texture which can cause the erosion yield to change with fluence due to changes in the aspect ratio of the surface texture that develops and polymer specific atomic oxygen interaction parameters. The surface texture development under directed hyperthermal attack produces higher aspect ratio surface texture than isotropic thermal energy atomic oxygen attack. The fluence dependence of erosion yields is documented for low Kapton H (DuPont, Wilmington, DE) effective fluences for a variety of polymers under directed hyperthermal and isotropic thermal energy attack.

  7. Aircraft Oxygen Generation

    Science.gov (United States)

    2012-02-01

    An Oxygen Enriched Air System for the AV-8A Harrier (NADC-81198-60).” 70 Horch , T., et. al. “The F-16 Onboard Oxygen Generating System: Performance...Only and Safety Privileged). Horch , T., Miller, R., Bomar, J., Tedor, J., Holden, R., Ikels, K., & Lozano, P. (1983). The F-16 Onboard Oxygen

  8. Structure of Greyhound hemoglobin: origin of high oxygen affinity.

    Science.gov (United States)

    Bhatt, Veer S; Zaldívar-López, Sara; Harris, David R; Couto, C Guillermo; Wang, Peng G; Palmer, Andre F

    2011-05-01

    This study presents the crystal structure of Greyhound hemoglobin (GrHb) determined to 1.9 Å resolution. GrHb was found to crystallize with an α₁β₁ dimer in the asymmetric unit and belongs to the R2 state. Oxygen-affinity measurements combined with the fact that GrHb crystallizes in the R2 state despite the high-salt conditions used for crystallization strongly indicate that GrHb can serve as a model high-oxygen-affinity hemoglobin (Hb) for higher mammals, especially humans. Structural analysis of GrHb and its comparison with the R2-state of human Hb revealed several regions that can potentially contribute to the high oxygen affinity of GrHb and serve to rationalize the additional stability of the R2-state of GrHb. A previously well studied hydrophobic cluster of bar-headed goose Hb near α119 was also incorporated in the comparison between GrHb and human Hb. Finally, a structural comparison with generic dog Hb and maned wolf Hb was conducted, revealing that in contrast to GrHb these structures belong to the R state of Hb and raising the intriguing possibility of an additional allosteric factor co-purifying with GrHb that can modulate its quaternary structure.

  9. Effects of palladium coatings on oxygen sensors of titanium dioxide thin films

    International Nuclear Information System (INIS)

    Castaneda, L.

    2007-01-01

    Titanium dioxide (TiO 2 -anatase phase) thin films were deposited by the ultrasonic spray pyrolysis technique employing titanium (IV) oxide acetylacetonate (TiO(acac) 2 ) dissolved in pure methanol as a source material. In order to prepare oxygen sensors, TiO 2 thin films were deposited on interdigitated gold electrodes with contacted alumina substrates. Palladium (Pd) coatings were carried out by vacuum thermal evaporation through a metallic mask. The effect of the surface additive (Pd) on the response of the thin film TiO 2 oxygen sensors was monitored in a mixture with zero-grade air. The electrical characterization (monitoring of the electrical surface resistance with the operation temperature) of the sensors in an atmosphere of oxygen (diluted in zero-grade air) was performed in a vacuum chamber (10 -6 Torr), where the gas pressure can be controlled. The films sensitivity was estimated by the following relation: s=R gas -R 0 /R 0 . The response time of the sensor is defined to be the time needed to reach a 0.9R 0 value when the oxygen excess is removed. The gas-sensing properties of TiO 2 sensors in an atmosphere of 10 4 ppm of oxygen were measured between 100 and 450 deg. C. Experimental results obtained using palladium as a surface additive show that the sensitivity reaches a stationary value of 1.18 for O 2 concentration of 100ppm in zero-grade air at 300 deg. C, which is as high as those reported for oxygen sensors prepared with more expensive and complex techniques. The role and activity of palladium coatings incorporated on solid-state oxygen sensors are determined by their chemical state, aggregation form and interaction with the metal-oxide semiconductor

  10. Age-dependent alterations of monocyte subsets and monocyte-related chemokine pathways in healthy adults

    Directory of Open Access Journals (Sweden)

    Trautwein Christian

    2010-06-01

    Full Text Available Abstract Background Recent experimental approaches have unraveled essential migratory and functional differences of monocyte subpopulations in mice. In order to possibly translate these findings into human physiology and pathophysiology, human monocyte subsets need to be carefully revisited in health and disease. In analogy to murine studies, we hypothesized that human monocyte subsets dynamically change during ageing, potentially influencing their functionality and contributing to immunosenescence. Results Circulating monocyte subsets, surface marker and chemokine receptor expression were analyzed in 181 healthy volunteers (median age 42, range 18-88. Unlike the unaffected total leukocyte or total monocyte counts, non-classical CD14+CD16+ monocytes significantly increased with age, but displayed reduced HLA-DR and CX3CR1 surface expression in the elderly. Classical CD14++CD16- monocyte counts did not vary dependent on age. Serum MCP-1 (CCL2, but not MIP1α (CCL3, MIP1β (CCL4 or fractalkine (CX3CL1 concentrations increased with age. Monocyte-derived macrophages from old or young individuals did not differ with respect to cytokine release in vitro at steady state or upon LPS stimulation. Conclusions Our study demonstrates dynamic changes of circulating monocytes during ageing in humans. The expansion of the non-classical CD14+CD16+ subtype, alterations of surface protein and chemokine receptor expression as well as circulating monocyte-related chemokines possibly contribute to the preserved functionality of the monocyte pool throughout adulthood.

  11. REST represses a subset of the pancreatic endocrine differentiation program

    DEFF Research Database (Denmark)

    Martin, David; Kim, Yung-Hae; Sever, Dror

    2015-01-01

    in neurons and in endocrine cells, which is necessary for their normal function. During development, REST represses a subset of genes in the neuronal differentiation program and Rest is down-regulated as neurons differentiate. Here, we investigate the role of REST in the differentiation of pancreatic...... endocrine cells, which are molecularly close to neurons. We show that Rest is widely expressed in pancreas progenitors and that it is down-regulated in differentiated endocrine cells. Sustained expression of REST in Pdx1(+) progenitors impairs the differentiation of endocrine-committed Neurog3...

  12. Oxygen enrichment incineration

    International Nuclear Information System (INIS)

    Kim, Jeong Guk; Yang, Hee Chul; Park, Geun Il; Kim, Joon Hyung

    2000-10-01

    Oxygen enriched combustion technology has recently been used in waste incineration. To apply the oxygen enrichment on alpha-bearing waste incineration, which is being developed, a state-of-an-art review has been performed. The use of oxygen or oxygen-enriched air instead of air in incineration would result in increase of combustion efficiency and capacity, and reduction of off-gas product. Especially, the off-gas could be reduced below a quarter, which might reduce off-gas treatment facilities, and also increase an efficiency of off-gas treatment. However, the use of oxygen might also lead to local overheating and high nitrogen oxides (NOx) formation. To overcome these problems, an application of low NOx oxy-fuel burner and recycling of a part of off-gas to combustion chamber have been suggested

  13. Oxygen enrichment incineration

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jeong Guk; Yang, Hee Chul; Park, Geun Il; Kim, Joon Hyung

    2000-10-01

    Oxygen enriched combustion technology has recently been used in waste incineration. To apply the oxygen enrichment on alpha-bearing waste incineration, which is being developed, a state-of-an-art review has been performed. The use of oxygen or oxygen-enriched air instead of air in incineration would result in increase of combustion efficiency and capacity, and reduction of off-gas product. Especially, the off-gas could be reduced below a quarter, which might reduce off-gas treatment facilities, and also increase an efficiency of off-gas treatment. However, the use of oxygen might also lead to local overheating and high nitrogen oxides (NOx) formation. To overcome these problems, an application of low NOx oxy-fuel burner and recycling of a part of off-gas to combustion chamber have been suggested.

  14. PKH26 staining defines distinct subsets of normal human colon epithelial cells at different maturation stages.

    Directory of Open Access Journals (Sweden)

    Anna Pastò

    Full Text Available BACKGROUND AND AIM: Colon crypts are characterized by a hierarchy of cells distributed along the crypt axis. Aim of this paper was to develop an in vitro system for separation of epithelial cell subsets in different maturation stages from normal human colon. METHODOLOGY AND MAJOR FINDINGS: Dissociated colonic epithelial cells were stained with PKH26, which allows identification of distinct populations based on their proliferation rate, and cultured in vitro in the absence of serum. The cytofluorimetric expression of CK20, Msi-1 and Lgr5 was studied. The mRNA levels of several stemness-associated genes were also compared in cultured cell populations and in three colon crypt populations isolated by microdissection. A PKH(pos population survived in culture and formed spheroids; this population included subsets with slow (PKH(high and rapid (PKH(low replicative rates. Molecular analysis revealed higher mRNA levels of both Msi-1 and Lgr-5 in PKH(high cells; by cytofluorimetric analysis, Msi-1(+/Lgr5(+ cells were only found within PKH(high cells, whereas Msi-1(+/Lgr5(- cells were also observed in the PKH(low population. As judged by qRT-PCR analysis, the expression of several stemness-associated markers (Bmi-1, EphB2, EpCAM, ALDH1 was highly enriched in Msi-1(+/Lgr5(+ cells. While CK20 expression was mainly found in PKH(low and PKH(neg cells, a small PKH(high subset co-expressed both CK20 and Msi-1, but not Lgr5; cells with these properties also expressed Mucin, and could be identified in vivo in colon crypts. These results mirrored those found in cells isolated from different crypt portions by microdissection, and based on proliferation rates and marker expression they allowed to define several subsets at different maturation stages: PKH(high/Lgr5(+/Msi-1(+/CK20(-, PKH(high/Lgr5(-/Msi-1(+/CK20(+, PKH(low/Lgr5(-/Msi-1(+/Ck20(-, and PKH(low/Lgr5(-/Msi-1(-/CK20(+ cells. CONCLUSIONS: Our data show the possibility of deriving in vitro, without any

  15. Some Observations on the Subset Simulation Related to the Wind Turbine Mechanics

    DEFF Research Database (Denmark)

    Sichani, Mahdi Teimouri; Nielsen, Søren R.K.; Thoft-Christensen, Palle

    2012-01-01

    systems. It is interesting to determine applicability of the Subset Simulation (SS) techniques, as a powerful representative of Variance Reduction Monte Carlo (VRMC) methods, on the wind turbine systems specifically with an active controller. Hence in this paper we apply and discuss these methods...... on a benchmark wind turbine model and analyze the results in view of their applicability....

  16. Effects of oxygen concentration on atmospheric pressure dielectric barrier discharge in Argon-Oxygen Mixture

    Science.gov (United States)

    Li, Xuechun; Li, Dian; Wang, Younian

    2016-09-01

    A dielectric barrier discharge (DBD) can generate a low-temperature plasma easily at atmospheric pressure and has been investigated for applications in trials in cancer therapy, sterilization, air pollution control, etc. It has been confirmed that reactive oxygen species (ROS) play a key role in the processes. In this work, we use a fluid model to simulate the plasma characteristics for DBD in argon-oxygen mixture. The effects of oxygen concentration on the plasma characteristics have been discussed. The evolution mechanism of ROS has been systematically analyzed. It was found that the ground state oxygen atoms and oxygen molecular ions are the dominated oxygen species under the considered oxygen concentrations. With the oxygen concentration increasing, the densities of electrons, argon atomic ions, resonance state argon atoms, metastable state argon atoms and excited state argon atoms all show a trend of decline. The oxygen molecular ions density is high and little influenced by the oxygen concentration. Ground state oxygen atoms density tends to increase before falling. The ozone density increases significantly. Increasing the oxygen concentration, the discharge mode begins to change gradually from the glow discharge mode to Townsend discharge mode. Project supported by the National Natural Science Foundation of China (Grant No. 11175034).

  17. Limitations of potentiometric oxygen sensors operating at low oxygen levels

    DEFF Research Database (Denmark)

    Lund, Anders; Jacobsen, Torben; Hansen, Karin Vels

    2011-01-01

    The electrochemical processes that limit the range of oxygen partial pressures in which potentiometric oxygen sensors can be used, were analysed using a theoretical and an experimental approach. Electrochemical impedance spectroscopy was performed on porous Pt/yttria stabilised zirconia (YSZ......) electrodes between 10−6 and 0.2 bar and at temperatures between 500 and 950 °C. The flow of oxide ions and electron holes through a sensor cell, with a YSZ electrolyte, were calculated under similar conditions. The oxygen permeation of the sensor cell was insignificant at an oxygen partial pressure of 10......−6 bar for an inlet flow rate higher than 2 L h−1 between 600 and 800 °C. The polarisation resistance measured between 10−6 and 10−4 bar was found to be inversely proportional to the oxygen partial pressure, nearly temperature independent and inversely proportional to the inlet gas flow rate, which shows...

  18. Do oxygen isotope values in collagen reflect the ecology and physiology of neotropical mammals?

    Directory of Open Access Journals (Sweden)

    Brooke eCrowley

    2015-11-01

    Full Text Available Stable isotope data provide insight into the foraging ecology of animals. Traditionally, carbon and nitrogen isotope values have been used to infer dietary and habitat preferences. Oxygen isotopes are used less frequently but may complement the ecological information provided by carbon and nitrogen, particularly in densely forested or arid environments. Additionally, because oxygen is preserved in both bioapatite and collagen, it is useful for paleoecological studies. To investigate the suitability of oxygen isotopes for complementing and building on ecological applications of carbon and nitrogen isotopes, we analyze all three isotopes in bone collagen for nearly identical assemblages of Costa Rican mammals in two ecologically distinct habitats - a evergreen rainforest and a seasonal dry forest. We assess the degree to which differences in habitat, activity pattern, diet, arboreality, and thermoregulation are revealed by each of the isotope systems. Our results highlight the potential of oxygen isotopes in modern and paleoecological contexts. In addition to reflecting habitat type, oxygen isotope values in collagen distinguish species on the basis of vertical habitat stratification and drinking behavior. Within a locality, individuals with low oxygen isotope values likely track meteoric water, whereas those with elevated values most likely consume evaporatively-enriched plant tissues, such as canopy leaves. These patterns will be useful in reconstructing paleoenvironments and interpreting ecological differences among taxa both extant and extinct.

  19. 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.

  20. Nature of oxygen donors and radiation defects in oxygen-doped germanium

    International Nuclear Information System (INIS)

    Fukuoka, Noboru; Atobe, Kozo; Honda, Makoto; Matsuda, Koji.

    1991-01-01

    The nature of oxygen donors and radiation defects in oxygen-doped germanium were studied through measurements of the infrared absorption spectrum, deep level transient spectroscopy spectrum and carrier concentration. It is revealed that a new donor is not formed in oxygen-doped germanium. An A-center (interstitial oxygen-vacancy pair) forms a complex with a thermal donor in its annealing stage at 60degC-140degC. The introduction rate of defects by 1.5 MeV electron irradiation was enhanced in thermal-donor-doped samples. (author)

  1. Intraportal islet oxygenation.

    Science.gov (United States)

    Suszynski, Thomas M; Avgoustiniatos, Efstathios S; Papas, Klearchos K

    2014-05-01

    Islet transplantation (IT) is a promising therapy for the treatment of diabetes. The large number of islets required to achieve insulin independence limit its cost-effectiveness and the number of patients who can be treated. It is believed that >50% of islets are lost in the immediate post-IT period. Poor oxygenation in the early post-IT period is recognized as a possible reason for islet loss and dysfunction but has not been extensively studied. Several key variables affect oxygenation in this setting, including (1) local oxygen partial pressure (pO(2)), (2) islet oxygen consumption, (3) islet size (diameter, D), and (4) presence or absence of thrombosis on the islet surface. We discuss implications of oxygen-limiting conditions on intraportal islet viability and function. Of the 4 key variables, the islet size appears to be the most important determinant of the anoxic and nonfunctional islet volume fractions. Similarly, the effect of thrombus formation on the islet surface may be substantial. At the University of Minnesota, average size distribution data from clinical alloislet preparations (n = 10) indicate that >150-µm D islets account for only ~30% of the total islet number, but >85% of the total islet volume. This suggests that improved oxygen supply to the islets may have a profound impact on islet survivability and function since most of the β-cell volume is within large islets which are most susceptible to oxygen-limiting conditions. The assumption that the liver is a suitable islet transplant site from the standpoint of oxygenation should be reconsidered. © 2014 Diabetes Technology Society.

  2. [Correlation between the inspired fraction of oxygen, maternal partial oxygen pressure, and fetal partial oxygen pressure during cesarean section of normal pregnancies].

    Science.gov (United States)

    Castro, Carlos Henrique Viana de; Cruvinel, Marcos Guilherme Cunha; Carneiro, Fabiano Soares; Silva, Yerkes Pereira; Cabral, Antônio Carlos Vieira; Bessa, Roberto Cardoso

    2009-01-01

    Despite changes in pulmonary function, maternal oxygenation is maintained during obstetric regional blocks. But in those situations, the administration of supplementary oxygen to parturients is a common practice. Good fetal oxygenation is the main justification; however, this has not been proven. The objective of this randomized, prospective study was to test the hypothesis of whether maternal hyperoxia is correlated with an increase in fetal gasometric parameters in elective cesarean sections. Arterial blood gases of 20 parturients undergoing spinal block with different inspired fractions of oxygen were evaluated and correlated with fetal arterial blood gases. An increase in maternal inspired fraction of oxygen did not show any correlation with an increase of fetal partial oxygen pressure. Induction of maternal hyperoxia by the administration of supplementary oxygen did not increase fetal partial oxygen pressure. Fetal gasometric parameters did not change even when maternal parameters changed, induced by hyperoxia, during cesarean section under spinal block.

  3. Electron attachment to molecules and clusters of atmospheric relevance: oxygen and ozone

    International Nuclear Information System (INIS)

    Matejcik, S.; Cicman, P.; Skalny, J.; Kiendler, A.; Stampfli, P.; Maerk, T.D.; Illenberger, E.; Chu, Y.; Stamatovic, A.

    1996-01-01

    Highly monochromatized electrons are used in a crossed beams experiment to investigate electron attachment to oxygen clusters (O 2 )-n at electron energies from approximately zero eV up to 2 eV. At energies close to zero the attachment cross section for the reaction (O 2 ) n + e → O 2 - varies inversely with the electron energy, indicative of s-wave electron capture to (O 2 ) n . Peaks in the attachment cross section present at higher energies can be ascribed to vibrational levels of the oxygen anion. The vibrational spacings observed can be quantitatively accounted for. In addition electron attachment to ozone and mixed oxygen/ozone clusters has been studied in the energy range up to 4 eV. Absolute attachment cross sections for both fragment ions anions, O - and O 2 - , from ozone could be deduced. Moreover, despite the initially large excess of oxygen molecules in the neutral oxygen/ozone clusters the dominant attachment products are un-dissociated cluster ions (O 3 ) m - including the O 3 - monomer while oxygen cluster ions (O 2 ) n appear with comparatively low intensity. (authors)

  4. Characteristics of Honeycomb-Type Oxygen Generator with Electrolyte Based on Doped Bismuth Oxide

    Science.gov (United States)

    Chen, Yu-Wen; Liu, Yi-Xin; Wang, Sea-Fue; Devasenathipathy, Rajkumar

    2018-03-01

    An oxygen generator using Y-doped Bi2O3 as electrolyte to transport oxygen ions has been developed, having honeycomb-type structure with dimensions of 40 mm × 35 mm × 30 mm and consisting of 13 × 12 channels. External wire circuitry for the channels arrayed using parallel, series, and hybrid connection was evaluated to achieve the best oxygen separation efficiency. It was observed that the oxygen generator with hybrid connection facilitated evolution of oxygen at maximum of 117 sccm and high purity > 99.9% at 550°C under current flow of 14 A. Addition of 5 wt.% silane and 3 wt.% glass-ceramic powder to the Ag slurry used at both electrodes not only increased the coverage of the metal electrode on the ceramic substrate during dip coating but also prevented cracking at the electrode layer of the module under stress from the electric field and temperature during high-temperature operation, thus reducing the decay rate of the oxygen generator in durability testing.

  5. Sunlight creates oxygenated species in water-soluble fractions of Deepwater horizon oil

    Energy Technology Data Exchange (ETDEWEB)

    Ray, Phoebe Z. [Department of Chemistry, University of New Orleans, New Orleans, LA 70148 (United States); Chen, Huan [National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, FL 32310-4005 (United States); Podgorski, David C. [National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, FL 32310-4005 (United States); Future Fuels Institute, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, FL 32310-4005 (United States); McKenna, Amy M. [National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, FL 32310-4005 (United States); Tarr, Matthew A., E-mail: mtarr@uno.edu [Department of Chemistry, University of New Orleans, New Orleans, LA 70148 (United States)

    2014-09-15

    Graphical abstract: Sunlight oxygenates petroleum. - Highlights: • Oxidation seen in water-soluble oil fraction after exposure to simulated sunlight. • Oxygen addition occurred across a wide range of carbon number and DBE. • Oil compounds were susceptible to addition of multiple oxygens to each molecule. • Results provide understanding of fate of oil on water after exposure to sunlight. - Abstract: In order to assess the impact of sunlight on oil fate, Macondo well oil from the Deepwater Horizon (DWH) rig was mixed with pure water and irradiated with simulated sunlight. After irradiation, the water-soluble organics (WSO) from the dark and irradiated samples were extracted and characterized by ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Liquid–liquid extraction yielded two fractions from dark and irradiated water/oil mixtures: acidic WSOs (negative-ion electrospray (ESI)), and base/neutral WSOs (positive-ion ESI) coupled to FT-ICR MS to catalog molecular-level transformations that occur to Macondo-derived WSOs after solar irradiation. Such direct measure of oil phototransformation has not been previously reported. The most abundant heteroatom class detected in the irradiated WSO acid fractions correspond to molecules that contain five oxygens (O{sub 5}), while the most abundant acids in the dark samples contain two oxygen atoms per molecule (O{sub 2}). Higher-order oxygen classes (O{sub 5}–O{sub 9}) were abundant in the irradiated samples, but <1.5% relative abundance in the dark sample. The increased abundance of higher-order oxygen classes in the irradiated samples relative to the dark samples indicates that photooxidized components of the Macondo crude oil become water-soluble after irradiation. The base/neutral fraction showed decreased abundance of pyridinic nitrogen (N{sub 1}) concurrent with an increased abundance of N{sub 1}O{sub x} classes after irradiation. The predominance of higher

  6. Evaluation of Oxygen Deficit Stress on Germination Indicators and Seedling

    Directory of Open Access Journals (Sweden)

    F Hoseini

    2012-06-01

    Full Text Available To investigate the relationship oxygen deficit stress on germination indicators and seedling growth of five wheat cultivars in laboratory condition, an experiment with Randomized Complete Block design in factorial arrangement with three replications was conducted in 2008. The treatments consisted of five wheat cultivars (Chamran, Flat, Roshan, Stare and Shole as A factor, and two oxygen level (normal seed and seed under oxygen deficit stress conditions as B factor in each of these figures was done. Results showed that oxygen deficit stress caused to decrease for various cultivars germination percentage, germination rate, allometric coefficient, seed vigor index and other germination indicators. Therefore, this test as a suitable method for determining the quality of various seed lot can be used in the water logging condition. In addition, among different cultivars characterized that Roshan cultivar was more resistant to oxygen deficit stress than Chamran, Flat and Star cultivars. Although Chamran cultivar is common cultivar in Khouzestan, but of look most germination indicators arranged as weak seed class. The highest correlation coefficients among the tested cultivars have been related to seed vigor with seedling length and dry weight of radicle with seedling with 0.92 and 0.90, respectively.

  7. The performance of tests on endogeneity of subsets of explanatory variables scanned by simulation

    NARCIS (Netherlands)

    Kiviet, J.F.; Pleus, M.

    2011-01-01

    Tests for classification as endogenous or predetermined of arbitrary subsets of regressors are formulated as significance tests in auxiliary IV regressions and their relationships with various more classic test procedures are examined. Simulation experiments are designed by solving the data

  8. Treg subsets in inflammatory bowel disease and colorectal carcinoma: Characteristics, role, and therapeutic targets

    NARCIS (Netherlands)

    van Herk, Egbert H.; te Velde, Anje A.

    2016-01-01

    T regulatory cells (Tregs) play an important role in the regulation of autoimmunity, autoinflammation, allergic diseases, infection, and the tumor environment. Different subsets are characterized that use a number of regulatory mechanisms. Tregs can influence the progression of inflammatory bowel

  9. A Longitudinal Study of the Role of T Cell subset, Th1/Th2 cytokines ...

    African Journals Online (AJOL)

    A Longitudinal Study of the Role of T Cell subset, Th1/Th2 cytokines and antiplasmodial antibodies in uncomplicated Malaria in a Village Population Chronically Exposed to Plasmodium falciparum Malaria.

  10. Oxygen configurations in silica

    International Nuclear Information System (INIS)

    Chelikowsky, James R.; Chadi, D. J.; Binggeli, N.

    2000-01-01

    We propose a transition state for oxygen in silica. This state is produced by the insertion of an oxygen molecule into the Si-O-Si bond, i.e., it consists of producing a Si-O-O-O-Si bond. This state allows molecular oxygen diffusion in silica without breaking the molecular O 2 bond and it is energetically more stable than a peroxy configuration. This configuration may allow for exchange of molecular oxygen with the oxygen in the silica framework. (c) 2000 The American Physical Society

  11. Oxygen transport by oxygen potential gradient in dense ceramic oxide membranes

    Energy Technology Data Exchange (ETDEWEB)

    Maiya, P.S.; Balachandran, U.; Dusek, J.T.; Mieville, R.L. [Argonne National Lab., IL (United States). Energy Technology Div.; Kleefisch, M.S.; Udovich, C.A. [Amoco Exploration/Production, Naperville, IL (United States)

    1996-05-01

    Numerous studies have been conducted in recent years on the partial oxidation of methane to synthesis gas (syngas: CO + H{sub 2}) with air as the oxidant. In partial oxidation, a mixed-oxide ceramic membrane selectively transports oxygen from the air; this transport is driven by the oxygen potential gradient. Of the several ceramic materials the authors have tested, a mixed oxide based on the Sr-Fe-Co-O system has been found to be very attractive. Extensive oxygen permeability data have been obtained for this material in methane conversion experiments carried out in a reactor. The data have been analyzed by a transport equation based on the phenomenological theory of diffusion under oxygen potential gradients. Thermodynamic calculations were used to estimate the driving force for the transport of oxygen ions. The results show that the transport equation deduced from the literature describes the permeability data reasonably well and can be used to determine the diffusion coefficients and the associated activation energy of oxygen ions in the ceramic membrane material.

  12. Oxygen Response of the Wine Yeast Saccharomyces cerevisiae EC1118 Grown under Carbon-Sufficient, Nitrogen-Limited Enological Conditions

    Science.gov (United States)

    Aceituno, Felipe F.; Orellana, Marcelo; Torres, Jorge; Mendoza, Sebastián; Slater, Alex W.; Melo, Francisco

    2012-01-01

    Discrete additions of oxygen play a critical role in alcoholic fermentation. However, few studies have quantitated the fate of dissolved oxygen and its impact on wine yeast cell physiology under enological conditions. We simulated the range of dissolved oxygen concentrations that occur after a pump-over during the winemaking process by sparging nitrogen-limited continuous cultures with oxygen-nitrogen gaseous mixtures. When the dissolved oxygen concentration increased from 1.2 to 2.7 μM, yeast cells changed from a fully fermentative to a mixed respirofermentative metabolism. This transition is characterized by a switch in the operation of the tricarboxylic acid cycle (TCA) and an activation of NADH shuttling from the cytosol to mitochondria. Nevertheless, fermentative ethanol production remained the major cytosolic NADH sink under all oxygen conditions, suggesting that the limitation of mitochondrial NADH reoxidation is the major cause of the Crabtree effect. This is reinforced by the induction of several key respiratory genes by oxygen, despite the high sugar concentration, indicating that oxygen overrides glucose repression. Genes associated with other processes, such as proline uptake, cell wall remodeling, and oxidative stress, were also significantly affected by oxygen. The results of this study indicate that respiration is responsible for a substantial part of the oxygen response in yeast cells during alcoholic fermentation. This information will facilitate the development of temporal oxygen addition strategies to optimize yeast performance in industrial fermentations. PMID:23001663

  13. Oxygen incorporation into GST phase-change memory matrix

    Energy Technology Data Exchange (ETDEWEB)

    Golovchak, R., E-mail: holovchakr@apsu.edu [Department of Physics and Astronomy, Austin Peay State University, Clarksville, TN 37044 (United States); Choi, Y.G. [Department of Materials Science and Engineering, Korea Aerospace University, Gyeonggi 412-791 (Korea, Republic of); Kozyukhin, S. [Kurnakov Institute of General and Inorganic Chemistry of RAS, 31 Leninsky Pr., Moscow 119991 (Russian Federation); National Research Tomsk State University, 36 Lenin Pr., Tomsk 634050 (Russian Federation); Chigirinsky, Yu. [Scientific-Research Physicotechnical Institute at the Nizhnii Novgorod State University, Nizhnii Novgorod 603600 (Russian Federation); Kovalskiy, A.; Xiong-Skiba, P.; Trimble, J. [Department of Physics and Astronomy, Austin Peay State University, Clarksville, TN 37044 (United States); Pafchek, R.; Jain, H. [Department of Materials Science and Engineering, Lehigh University, 5 East Packer Avenue, Bethlehem, PA 18015-3195 (United States)

    2015-03-30

    Graphical abstract: - Highlights: • Surfaces of GST-225 films are depleted in Te as a result of the reaction with oxygen. • Top layers of oxidized GST-225 are formed by Sb and Ge oxide complexes. • Depth profiles of Sb and Ge oxide complexes are found to be different. • Crystallization at 300 °C in O{sub 2} atmosphere leads to Ge redistribution. - Abstract: Structural changes in amorphous and crystallized GST-225 films induced by the reaction with oxygen are studied at different depth scales. The mechanism of interaction of the very top surface layers with oxygen is studied with low-energy ion scattering (LEIS) technique, while the modifications of chemistry in the underlying surface layers are investigated with high-resolution X-ray photoelectron spectroscopy (XPS). The changes averaged through the overall film thickness are characterized by micro-Raman spectroscopy. The oxygen exposure leads to a depletion of GST-225 film surfaces in Te and formation of the antimony and germanium oxides. The antimony oxide complexes are found throughout the whole thickness of the films after their prolonged storage in air, whereas no evidence for formation of pure GeO{sub 2} phase is found in the volume of the films through Raman spectroscopy. A tendency to form Ge-rich phase within the ∼10 nm surface layer is additionally observed by LEIS profiling during crystallization of GST-225 film at 300 °C in oxygen atmosphere.

  14. Beneficial Effects of cART Initiated during Primary and Chronic HIV-1 Infection on Immunoglobulin-Expression of Memory B-Cell Subsets.

    Directory of Open Access Journals (Sweden)

    Manuela Pogliaghi

    Full Text Available During HIV-1 infection the B-cell compartment undergoes profound changes towards terminal differentiation, which are only partially restored by antiretroviral therapy (cART.To investigate the impact of infection as early as during primary HIV-1 infection (PHI we assessed distribution of B-cell subsets in 19 PHI and 25 chronic HIV-1-infected (CHI individuals before and during 48 weeks of cART as compared to healthy controls (n = 23. We also analysed Immunoglobulin-expression of memory B-cell subsets to identify alterations in Immunoglobulin-maturation.Determination of B-cell subsets at baseline showed that total and Naive B-cells were decreased whereas Activated Memory (AM, Tissue-like Memory (TLM B-cells and Plasma cells were increased in both PHI and CHI patients. After 4 weeks of cART total B-cells increased, while AM, TLM B-cells and Plasma cells decreased, although without reaching normal levels in either group of individuals. This trend was maintained until week 48, though only total B-cells normalized in both PHI and CHI. Resting Memory (RM B-cells were preserved since baseline. This subset remained stable in CHI, while was expanded by an early initiation of cART during PHI. Untreated CHI patients showed IgM-overexpression at the expenses of switched (IgM-IgD- phenotypes of the memory subsets. Interestingly, in PHI patients a significant alteration of Immunoglobulin-expression was evident at BL in TLM cells, and after 4 weeks, despite treatment, in AM and RM subsets. After 48 weeks of therapy, Immunoglobulin-expression of AM and RM almost normalized, but remained perturbed in TLM cells in both groups.In conclusion, aberrant activated and exhausted B-cell phenotypes rose already during PHI, while most of the alterations in Ig-expression seen in CHI appeared later, despite 4 weeks of effective cART. After 48 weeks of cART B-cell subsets distribution improved although without full normalization, while Immunoglobulin-expression normalized

  15. Beneficial Effects of cART Initiated during Primary and Chronic HIV-1 Infection on Immunoglobulin-Expression of Memory B-Cell Subsets.

    Science.gov (United States)

    Pogliaghi, Manuela; Ripa, Marco; Pensieroso, Simone; Tolazzi, Monica; Chiappetta, Stefania; Nozza, Silvia; Lazzarin, Adriano; Tambussi, Giuseppe; Scarlatti, Gabriella

    2015-01-01

    During HIV-1 infection the B-cell compartment undergoes profound changes towards terminal differentiation, which are only partially restored by antiretroviral therapy (cART). To investigate the impact of infection as early as during primary HIV-1 infection (PHI) we assessed distribution of B-cell subsets in 19 PHI and 25 chronic HIV-1-infected (CHI) individuals before and during 48 weeks of cART as compared to healthy controls (n = 23). We also analysed Immunoglobulin-expression of memory B-cell subsets to identify alterations in Immunoglobulin-maturation. Determination of B-cell subsets at baseline showed that total and Naive B-cells were decreased whereas Activated Memory (AM), Tissue-like Memory (TLM) B-cells and Plasma cells were increased in both PHI and CHI patients. After 4 weeks of cART total B-cells increased, while AM, TLM B-cells and Plasma cells decreased, although without reaching normal levels in either group of individuals. This trend was maintained until week 48, though only total B-cells normalized in both PHI and CHI. Resting Memory (RM) B-cells were preserved since baseline. This subset remained stable in CHI, while was expanded by an early initiation of cART during PHI. Untreated CHI patients showed IgM-overexpression at the expenses of switched (IgM-IgD-) phenotypes of the memory subsets. Interestingly, in PHI patients a significant alteration of Immunoglobulin-expression was evident at BL in TLM cells, and after 4 weeks, despite treatment, in AM and RM subsets. After 48 weeks of therapy, Immunoglobulin-expression of AM and RM almost normalized, but remained perturbed in TLM cells in both groups. In conclusion, aberrant activated and exhausted B-cell phenotypes rose already during PHI, while most of the alterations in Ig-expression seen in CHI appeared later, despite 4 weeks of effective cART. After 48 weeks of cART B-cell subsets distribution improved although without full normalization, while Immunoglobulin-expression normalized among AM and

  16. Comparison of domiciliary oxygen using liquid oxygen and concentrator in northern Taiwan

    Directory of Open Access Journals (Sweden)

    Chien-Ling Su

    2014-01-01

    Conclusion: Patients in the LOG used oxygen for longer hours, went on more outings, and were more likely to travel with oxygen than patients in the OCG. Being ambulatory with liquid oxygen might enable patients with COPD to walk more effectively.

  17. Nasal Cannula Apneic Oxygenation Prevents Desaturation During Endotracheal Intubation: An Integrative Literature Review

    Directory of Open Access Journals (Sweden)

    Bill R. Christian

    2018-02-01

    Full Text Available Patients requiring emergency airway management may be at greater risk of acute hypoxemic events because of underlying lung pathology, high metabolic demands, insufficient respiratory drive, obesity, or the inability to protect their airway against aspiration. Emergency tracheal intubation is often required before complete information needed to assess the risk of procedural hypoxia is acquired (i.e., arterial blood gas level, hemoglobin value, or chest radiograph. During pre-oxygenation, administering high-flow nasal oxygen in addition to a non-rebreather face mask can significantly boost the effective inspired oxygen. Similarly, with the apnea created by rapid sequence intubation (RSI procedures, the same high-flow nasal cannula can help maintain or increase oxygen saturation during efforts to secure the tube (oral intubation. Thus, the use of nasal oxygen during pre-oxygenation and continued during apnea can prevent hypoxia before and during intubation, extending safe apnea time, and improve first-pass success attempts. We conducted a literature review of nasal-cannula apneic oxygenation during intubation, focusing on two components: oxygen saturation during intubation, and oxygen desaturation time. We performed an electronic literature search from 1980 to November 2017, using PubMed, Elsevier, ScienceDirect, and EBSCO. We identified 14 studies that pointed toward the benefits of using nasal cannula during emergency intubation.

  18. Simultaneous Monitoring of Vascular Oxygenation and Tissue Oxygen Tension of Breast Tumors Under Hyperbaric Oxygen Exposure

    Science.gov (United States)

    2008-04-01

    28. Alagoz, T., R. Buller, B. Anderson, K. Terrell , R...and oxygenation Ann . New Acad. Sci. 838 29–45 Chapman J D, Stobbe C C, Arnfield M R, Santus R, Lee J and McPhee M S 1991 Oxygen dependency of tumor

  19. A Typical Immune T/B Subset Profile Characterizes Bicuspid Aortic Valve: In an Old Status?

    Directory of Open Access Journals (Sweden)

    Carmela R. Balistreri

    2018-01-01

    Full Text Available Bicuspid valve disease is associated with the development of thoracic aortic aneurysm. The molecular mechanisms underlying this association still need to be clarified. Here, we evaluated the circulating levels of T and B lymphocyte subsets associated with the development of vascular diseases in patients with bicuspid aortic valve or tricuspid aortic valve with and without thoracic aortic aneurysm. We unveiled that the circulating levels of the MAIT, CD4+IL−17A+, and NKT T cell subsets were significantly reduced in bicuspid valve disease cases, when compared to tricuspid aortic valve cases in either the presence or the absence of thoracic aortic aneurysm. Among patients with tricuspid aortic valve, these cells were higher in those also affected by thoracic aortic aneurysm. Similar data were obtained by examining CD19+ B cells, naïve B cells (IgD+CD27−, memory unswitched B cells (IgD+CD27+, memory switched B cells (IgD−CD27+, and double-negative B cells (DN (IgD−CD27−. These cells resulted to be lower in subjects with bicuspid valve disease with respect to patients with tricuspid aortic valve. In whole, our data indicate that patients with bicuspid valve disease show a quantitative reduction of T and B lymphocyte cell subsets. Future studies are encouraged to understand the molecular mechanisms underlying this observation and its pathophysiological significance.

  20. Effect of ternary additions on the oxidation resistance of Ti5Si3

    International Nuclear Information System (INIS)

    Thom, A.J.; Akinc, M.; Iowa State Univ., Ames, IA

    1995-01-01

    Refractory intermetallic silicides are receiving increasing consideration for use as high temperature structural materials. Ti 5 Si 3 -based compositions are attractive due to their ability to incorporate a variety of interstitial ternary additions. These ternary additions present a unique opportunity to potentially tailor physical properties. Previous experimental work has shown that these additions significantly increase the otherwise poor oxidation resistance of undoped Ti 5 Si 3 above 700 C. Recent experimental work by the authors on the oxidation of small atom doped Ti 5 Si 3 is discussed. Interstitial additions of boron, carbon, and oxygen substantially improve the isothermal oxidation resistance of Ti 5 Si 3 at 1,000 C. In contrast, added nitrogen does not provide significant improvement. Even up to 1,306 C, interstitial oxygen imparts excellent oxidation resistance with a mass gain of 1.1 mg/cm 2 after 240 hours

  1. T cell subsets in human airways prior to and following endobronchial administration of endotoxin

    DEFF Research Database (Denmark)

    Ronit, Andreas; Plovsing, Ronni R; Gaardbo, Julie C

    2015-01-01

    BACKGROUND AND OBJECTIVES: Bronchial instillation of lipopolysaccharide (LPS) provides a reversible model of lung inflammation that may resemble early stages of acute respiratory distress syndrome (ARDS). We investigated the distributions of T-cell subsets in the human airways and sought to deter...

  2. SDHA loss of function mutations in a subset of young adult wild-type gastrointestinal stromal tumors

    International Nuclear Information System (INIS)

    Italiano, Antoine; Chen, Chun-Liang; Sung, Yun-Shao; Singer, Samuel; DeMatteo, Ronald P; LaQuaglia, Michael P; Besmer, Peter; Socci, Nicholas; Antonescu, Cristina R

    2012-01-01

    A subset of KIT/PDGFRA wild-type gastrointestinal stromal tumors (WT GIST) have been associated with alteration of the succinate dehydrogenase (SDH) complex II function. A recent report identified four non-syndromic, KIT/PDGFRA WT GIST harboring compound heterozygous or homozygous mutations in SDHA encoding the main subunit of the SDH complex II. Next generation sequencing was applied on five pediatric and one young adult WT GIST, by whole exome capture and SOLiD 3-plus system sequencing. The putative mutations were first confirmed by Sanger sequencing and then screened on a larger panel of 11 pediatric and young adult WT GIST, including 5 in the context of Carney triad. A germline p.Arg31X nonsense SDHA mutation was identified in one of the six cases tested by SOLiD platform. An additional p.D38V missense mutation in SDHA exon 2 was identified by Sanger sequencing in the extended KIT/PDGFRA WT GIST patients cohort. Western blotting showed loss of SDHA expression in the two cases harboring SDHA mutations, while expression being retained in the other WT GIST tumors. Results were further confirmed by immunohistochemistry for both SDHA and SDHB, which showed a concurrent loss of expression of both proteins in SDHA-mutant lesions, while the remaining WT tumors showed only loss of SDHB expression. Germline and/or somatic aberrations of SDHA occur in a small subset of KIT/PDGFRA WT GISTs, outside the Carney’s triad and are associated with loss of both SDHA and SDHB protein expression. Mutations of the SDH complex II are more particularly associated with KIT/PDGFRA WT GIST occurring in young adults. Although pediatric GIST consistently display alterations of SDHB protein expression, further molecular studies are needed to identify the crucial genes involved in their tumorigenesis

  3. Evolving Oxygen Landscape of the Early Atmosphere and Oceans

    Science.gov (United States)

    Lyons, T. W.; Reinhard, C. T.; Planavsky, N. J.

    2013-12-01

    we see evidence for an oxygenation event that significantly predated recent evidence for ocean ventilation in the post-glacial Ediacaran ocean. The trigger that facilitated the transition out of the oxygen-lean ';boring billion' is an area of active study. Additional evidence points to the likelihood of rising and falling oxygen levels through the later Neoproterozoic, which would have had a strong impact on early animal diversification and development of oxygen-demanding ecologies marked by large animals with complex trophic relationships. These observations now provide a context for interpreting the cause-and-effect relationships among the late Proterozoic rise in oxygen, the onset and dynamics of global-scale Neoproterozoic glaciation, metazoan diversification, and large-scale tectonic processes as surface expressions of deep-Earth processes.

  4. Corrosion resistance improvement of ferritic steels through hydrogen additions to the BWR coolant

    International Nuclear Information System (INIS)

    Gordon, B.M.; Jewett, C.W.; Pickett, A.E.; Indig, M.E.

    1984-01-01

    Motivated by the success of oxygen suppression for mitigation of intergranular stress corrosion cracking (IGSCC) in weld sensitized austenitic materials used in Boiling Water Reactors (BWRs), oxygen suppression, through hydrogen additions to the feedwater was investigated to determine its affect on the corrosion resistance of ferritic and martensitic BWR structural materials. The results of these investigations are presented in this paper, where particular emphasis is placed on the corrosion performance of BWR pressure vessel low alloy steels, carbon steel piping materials and martensitic pump materials. It is important to note that the corrosion resistance of these materials in the BWR environment is excellent. Consequently this investigation was also motivated to determine whether there were any detrimental effects of hydrogen additions, as well as to identify any additional margin in ferritic/martensitic materials corrosion performance

  5. Control of oxygen tension recapitulates zone-specific functions in human liver microphysiology systems.

    Science.gov (United States)

    Lee-Montiel, Felipe T; George, Subin M; Gough, Albert H; Sharma, Anup D; Wu, Juanfang; DeBiasio, Richard; Vernetti, Lawrence A; Taylor, D Lansing

    2017-10-01

    This article describes our next generation human Liver Acinus MicroPhysiology System (LAMPS). The key demonstration of this study was that Zone 1 and Zone 3 microenvironments can be established by controlling the oxygen tension in individual devices over the range of ca. 3 to 13%. The oxygen tension was computationally modeled using input on the microfluidic device dimensions, numbers of cells, oxygen consumption rates of hepatocytes, the diffusion coefficients of oxygen in different materials and the flow rate of media in the MicroPhysiology System (MPS). In addition, the oxygen tension was measured using a ratiometric imaging method with the oxygen sensitive dye, Tris(2,2'-bipyridyl) dichlororuthenium(II) hexahydrate (RTDP) and the oxygen insensitive dye, Alexa 488. The Zone 1 biased functions of oxidative phosphorylation, albumin and urea secretion and Zone 3 biased functions of glycolysis, α1AT secretion, Cyp2E1 expression and acetaminophen toxicity were demonstrated in the respective Zone 1 and Zone 3 MicroPhysiology System. Further improvements in the Liver Acinus MicroPhysiology System included improved performance of selected nonparenchymal cells, the inclusion of a porcine liver extracellular matrix to model the Space of Disse, as well as an improved media to support both hepatocytes and non-parenchymal cells. In its current form, the Liver Acinus MicroPhysiology System is most amenable to low to medium throughput, acute through chronic studies, including liver disease models, prioritizing compounds for preclinical studies, optimizing chemistry in structure activity relationship (SAR) projects, as well as in rising dose studies for initial dose ranging. Impact statement Oxygen zonation is a critical aspect of liver functions. A human microphysiology system is needed to investigate the impact of zonation on a wide range of liver functions that can be experimentally manipulated. Because oxygen zonation has such diverse physiological effects in the liver, we

  6. Recombination and detachment in oxygen discharges: the role of metastable oxygen molecules

    International Nuclear Information System (INIS)

    Gudmundsson, J T

    2004-01-01

    A global (volume averaged) model of oxygen discharges is used to study the transition from a recombination dominated discharge to a detachment dominated discharge. The model includes the metastable oxygen molecules O 2 (a 1 Δ g ) and O 2 (b 1 Σ g + ) and the three Herzberg states O 2 (A 3 Σ u + , A' 3 Δ u , c 1 Σ u - ). Dissociative attachment of the oxygen molecule in the ground state O 2 ( 3 Σ g - ) and the metastable oxygen molecule O 2 (a 1 Δ g ) are the dominating channels for creation of the negative oxygen ion O - . At high pressures, dissociative attachment of the Herzberg states contributes significantly to the creation of the negative oxygen ion, O - . The detachment by a collision of the metastable oxygen molecule O 2 (b 1 Σ g + ) with the oxygen ion, O - , is a significant loss process for the O - at pressures above 10 mTorr. Its contribution to the loss is more significant at a lower applied power, but at the higher pressures it is always significant. Detachment by collision with O( 3 P) is also an important loss mechanism for O - . We find that ion-ion recombination is the dominating loss process for negative ions in oxygen discharges at low pressures and calculate the critical pressure where the contributions of recombination reactions and detachment reactions are equal. This critical pressure depends on the applied power, increases with applied power and is in the range 5-14 mTorr in the pressure and power range investigated

  7. Spray generator of singlet oxygen for a chemical oxygen-iodine laser

    Czech Academy of Sciences Publication Activity Database

    Jirásek, Vít; Hrubý, Jan; Špalek, Otomar; Čenský, Miroslav; Kodymová, Jarmila

    2010-01-01

    Roč. 100, č. 4 (2010), s. 779-791 ISSN 0946-2171 Grant - others:European Office of Aerospace R&D(US) FA8655-09-1-3091 Institutional research plan: CEZ:AV0Z10100523; CEZ:AV0Z20760514 Keywords : spray generator of singlet oxygen * singlet oxygen * chemical oxygen-iodine laser Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.239, year: 2010

  8. Expansion of mycobacterium-reactive gamma delta T cells by a subset of memory helper T cells.

    Science.gov (United States)

    Vila, L M; Haftel, H M; Park, H S; Lin, M S; Romzek, N C; Hanash, S M; Holoshitz, J

    1995-04-01

    Human gamma delta T cells expressing the V gamma 9/V delta 2 T-cell receptor have been previously found to proliferate in response to certain microorganisms and to expand throughout life, presumably because of extrathymic activation by foreign antigens. In vitro expansion of V gamma 9/V delta 2 cells by mycobacteria has been previously shown to be dependent on accessory cells. In order to gain an insight into the mechanisms involved in the expansion of these cells, we have undertaken to identify the peripheral blood subset of cells on which proliferation of V gamma 9/V delta 2 cells in response to mycobacteria is dependent. Contrary to their role in antigen presentation to alpha beta T cells, professional antigen-presenting cells, such as monocytes, B cells, and dendritic cells, were unable to provide the cellular support for the expansion of V gamma 9/V delta 2 cells. Selective depletion of T-cell subsets, as well as the use of highly purified T-cell populations, indicated that the only subset of peripheral blood cells that could expand V gamma 9/V delta 2 cells were CD4+ CD45RO+ CD7- alpha beta T cells. These cells underwent distinct intracellular signaling events after stimulation with the mycobacterial antigen. Expansion of V gamma 9/V delta 2 cells by alpha beta T cells was dependent on cell-cell contact. This is the first evidence that a small subset of the memory helper T-cell population is exclusively responsible for the peripheral expansion of V gamma 9/V delta 2 cells. These data illustrate a unique aspect of antigen recognition by gamma delta T cells and provide new means to study their immune defense role.

  9. Flow cytometry analysis of T-cell subsets in cerebrospinal fluid of narcolepsy type 1 patients with long-lasting disease

    DEFF Research Database (Denmark)

    Moresco, Monica; Lecciso, Mariangela; Ocadlikova, Darina

    2018-01-01

    BACKGROUND: Type 1 narcolepsy (NT1) is a central hypersomnia linked to the destruction of hypocretin-producing neurons. A great body of genetic and epidemiological data points to likely autoimmune disease aetiology. Recent reports have characterized peripheral blood T-cell subsets in NT1, whereas...... data regarding the cerebrospinal fluid (CSF) immune cell composition are lacking. The current study aimed to characterize the T-cell and natural killer (NK) cell subsets in NT1 patients with long disease course. METHODS: Immune cell subsets from CSF and peripheral blood mononuclear cell (PBMC) samples...... were analysed by flow cytometry in two age-balanced and sex-balanced groups of 14 NT1 patients versus 14 healthy controls. The frequency of CSF cell groups was compared with PBMCs. Non-parametric tests were used for statistical analyses. RESULTS: The NT1 patients did not show significant differences...

  10. Effects of the oxygenation level on formation of different reactive oxygen species during photodynamic therapy.

    Science.gov (United States)

    Price, Michael; Heilbrun, Lance; Kessel, David

    2013-01-01

    We examined the effect of the oxygenation level on efficacy of two photosensitizing agents, both of which target lysosomes for photodamage, but via different photochemical pathways. Upon irradiation, the chlorin termed NPe6 forms singlet oxygen in high yield while the bacteriopheophorbide WST11 forms only oxygen radicals (in an aqueous environment). Photokilling efficacy by WST11 in cell culture was impaired when the atmospheric oxygen concentration was reduced from 20% to 1%, while photokilling by NPe6 was unaffected. Studies in a cell-free system revealed that the rates of photobleaching of these agents, as a function of the oxygenation level, were correlated with results described above. Moreover, the rate of formation of oxygen radicals by either agent was more sensitive to the level of oxygenation than was singlet oxygen formation by NPe6. These data indicate that the photochemical process that leads to oxygen radical formation is more dependent on the oxygenation level than is the pathway leading to formation of singlet oxygen. © 2013 Wiley Periodicals, Inc. Photochemistry and Photobiology © 2013 The American Society of Photobiology.

  11. Leukocyte counts and lymphocyte subsets in relation to pregnancy and HIV infection in Malawian women.

    Science.gov (United States)

    Mandala, Wilson L; Gondwe, Esther N; Molyneux, Malcolm E; MacLennan, Jenny M; MacLennan, Calman A

    2017-09-01

    We investigated leukocyte and lymphocyte subsets in HIV-infected or HIV-uninfected, pregnant or non-pregnant Malawian women to explore whether HIV infection and pregnancy may act synergistically to impair cellular immunity. We recruited 54 pregnant and 48 non-pregnant HIV-uninfected women and 24 pregnant and 20 non-pregnant HIV-infected Malawian women. We compared peripheral blood leukocyte and lymphocyte subsets between women in the four groups. Parturient HIV-infected and HIV-uninfected women had more neutrophils (each PHIV-uninfected parturient women had fewer CD4 + and γδ T cells, B and NK cells (each Ppregnancy. Malawian women at parturition have an increased total white cell count due to neutrophilia and an HIV-unrelated pan-lymphopenia. © 2017 The Author. American Journal of Reproductive Immunology Published by John Wiley & Sons Ltd.

  12. Advanced Oxygen Systems for Aircraft (Systemes d’Oxygene Avances)

    Science.gov (United States)

    1996-04-01

    Oxygen Generating System (NAOGS), SAM-TR-80-12, Brooks AFB TX 78235, 1980. 11. Horch TC, Miller RL, Bomar JB, Tedor JB, Holden RD, Ikels KG, and...sieve oxygen generation sys- tem. Data from Horch et al (15). cabin altitude. The minimum and maximum oxygen concen- tration lines depict the...an AV-8A Aircraft; Naval Air Test Center Report No. SY-136R-81, 1981. 15. Horch TC, Miller RL, Bomar JB Jr, Tedor JB, Holden RD, Ikels KG, and

  13. Sediment-Overlying Water Relationships Affecting Wintertime Dissolved Oxygen Conditions in the Big Eau Pleine Reservoir, Wisconsin.

    Science.gov (United States)

    1992-07-01

    22202-4302. and to the Office of Managel ent and Bidget . P worki Reduction Pfo4ect(07T4-016 Wahington. DC 20S03. -1. AGENCY USE ONLY (Leave blank) 2...higher pool elevation can not be maintained, it is likely that additional aerators must be installed for incremental use to meet periodic heavy oxygen...install additional aerators throughout the reservoir for incremental use as needed to enhance oxygen diffusion processes. The difficulty with this

  14. Additive Manufactured Superconducting Cavities

    Science.gov (United States)

    Holland, Eric; Rosen, Yaniv; Woolleet, Nathan; Materise, Nicholas; Voisin, Thomas; Wang, Morris; Mireles, Jorge; Carosi, Gianpaolo; Dubois, Jonathan

    Superconducting radio frequency cavities provide an ultra-low dissipative environment, which has enabled fundamental investigations in quantum mechanics, materials properties, and the search for new particles in and beyond the standard model. However, resonator designs are constrained by limitations in conventional machining techniques. For example, current through a seam is a limiting factor in performance for many waveguide cavities. Development of highly reproducible methods for metallic parts through additive manufacturing, referred to colloquially as 3D printing\\x9D, opens the possibility for novel cavity designs which cannot be implemented through conventional methods. We present preliminary investigations of superconducting cavities made through a selective laser melting process, which compacts a granular powder via a high-power laser according to a digitally defined geometry. Initial work suggests that assuming a loss model and numerically optimizing a geometry to minimize dissipation results in modest improvements in device performance. Furthermore, a subset of titanium alloys, particularly, a titanium, aluminum, vanadium alloy (Ti - 6Al - 4V) exhibits properties indicative of a high kinetic inductance material. This work is supported by LDRD 16-SI-004.

  15. Multi-lingual search engine to access PubMed monolingual subsets: a feasibility study.

    Science.gov (United States)

    Darmoni, Stéfan J; Soualmia, Lina F; Griffon, Nicolas; Grosjean, Julien; Kerdelhué, Gaétan; Kergourlay, Ivan; Dahamna, Badisse

    2013-01-01

    PubMed contains many articles in languages other than English but it is difficult to find them using the English version of the Medical Subject Headings (MeSH) Thesaurus. The aim of this work is to propose a tool allowing access to a PubMed subset in one language, and to evaluate its performance. Translations of MeSH were enriched and gathered in the information system. PubMed subsets in main European languages were also added in our database, using a dedicated parser. The CISMeF generic semantic search engine was evaluated on the response time for simple queries. MeSH descriptors are currently available in 11 languages in the information system. All the 654,000 PubMed citations in French were integrated into CISMeF database. None of the response times exceed the threshold defined for usability (2 seconds). It is now possible to freely access biomedical literature in French using a tool in French; health professionals and lay people with a low English language may find it useful. It will be expended to several European languages: German, Spanish, Norwegian and Portuguese.

  16. Random-subset fitting of digital holograms for fast three-dimensional particle tracking [invited].

    Science.gov (United States)

    Dimiduk, Thomas G; Perry, Rebecca W; Fung, Jerome; Manoharan, Vinothan N

    2014-09-20

    Fitting scattering solutions to time series of digital holograms is a precise way to measure three-dimensional dynamics of microscale objects such as colloidal particles. However, this inverse-problem approach is computationally expensive. We show that the computational time can be reduced by an order of magnitude or more by fitting to a random subset of the pixels in a hologram. We demonstrate our algorithm on experimentally measured holograms of micrometer-scale colloidal particles, and we show that 20-fold increases in speed, relative to fitting full frames, can be attained while introducing errors in the particle positions of 10 nm or less. The method is straightforward to implement and works for any scattering model. It also enables a parallelization strategy wherein random-subset fitting is used to quickly determine initial guesses that are subsequently used to fit full frames in parallel. This approach may prove particularly useful for studying rare events, such as nucleation, that can only be captured with high frame rates over long times.

  17. Kinetics of oxygen species in an electrically driven singlet oxygen generator

    Science.gov (United States)

    Azyazov, V. N.; Torbin, A. P.; Pershin, A. A.; Mikheyev, P. A.; Heaven, M. C.

    2015-12-01

    The kinetics of oxygen species in the gaseous medium of a discharge singlet oxygen generator has been revisited. Vibrationally excited ozone O3(υ) formed in O + O2 recombination is thought to be a significant agent in the deactivation of singlet oxygen O2(a1Δ), oxygen atom removal and ozone formation. It is shown that the process O3(υ ⩾ 2) + O2(a1Δ) → 2O2 + O is the main O2(a1Δ) deactivation channel in the post-discharge zone. If no measures are taken to decrease the oxygen atom concentration, the contribution of this process to the overall O2(a1Δ) removal is significant, even in the discharge zone. A simplified model for the kinetics of vibrationally excited ozone is proposed. Calculations based on this model yield results that are in good agreement with the experimental data.

  18. Oxygen therapy reduces postoperative tachycardia

    DEFF Research Database (Denmark)

    Stausholm, K; Kehlet, H; Rosenberg, J

    1995-01-01

    Concomitant hypoxaemia and tachycardia in the postoperative period is unfavourable for the myocardium. Since hypoxaemia per se may be involved in the pathogenesis of postoperative tachycardia, we have studied the effect of oxygen therapy on tachycardia in 12 patients randomly allocated to blinded...... air or oxygen by facemask on the second or third day after major surgery. Inclusion criteria were arterial hypoxaemia (oxygen saturation 90 beat.min-1). Each patient responded similarly to oxygen therapy: an increase in arterial oxygen saturation and a decrease...... in heart rate (p oxygen has a positive effect on the cardiac oxygen delivery and demand balance....

  19. The Not-So-Global Blood Oxygen Level-Dependent Signal.

    Science.gov (United States)

    Billings, Jacob; Keilholz, Shella

    2018-04-01

    Global signal regression is a controversial processing step for resting-state functional magnetic resonance imaging, partly because the source of the global blood oxygen level-dependent (BOLD) signal remains unclear. On the one hand, nuisance factors such as motion can readily introduce coherent BOLD changes across the whole brain. On the other hand, the global signal has been linked to neural activity and vigilance levels, suggesting that it contains important neurophysiological information and should not be discarded. Any widespread pattern of coordinated activity is likely to contribute appreciably to the global signal. Such patterns may include large-scale quasiperiodic spatiotemporal patterns, known also to be tied to performance on vigilance tasks. This uncertainty surrounding the separability of the global BOLD signal from concurrent neurological processes motivated an examination of the global BOLD signal's spatial distribution. The results clarify that although the global signal collects information from all tissue classes, a diverse subset of the BOLD signal's independent components contribute the most to the global signal. Further, the timing of each network's contribution to the global signal is not consistent across volunteers, confirming the independence of a constituent process that comprises the global signal.

  20. Comprehensive Approach for Identifying the T Cell Subset Origin of CD3 and CD28 Antibody-Activated Chimeric Antigen Receptor-Modified T Cells.

    Science.gov (United States)

    Schmueck-Henneresse, Michael; Omer, Bilal; Shum, Thomas; Tashiro, Haruko; Mamonkin, Maksim; Lapteva, Natalia; Sharma, Sandhya; Rollins, Lisa; Dotti, Gianpietro; Reinke, Petra; Volk, Hans-Dieter; Rooney, Cliona M

    2017-07-01

    The outcome of therapy with chimeric Ag receptor (CAR)-modified T cells is strongly influenced by the subset origin of the infused T cells. However, because polyclonally activated T cells acquire a largely CD45RO + CCR7 - effector memory phenotype after expansion, regardless of subset origin, it is impossible to know which subsets contribute to the final T cell product. To determine the contribution of naive T cell, memory stem T cell, central memory T cell, effector memory T cell, and terminally differentiated effector T cell populations to the CD3 and CD28-activated CAR-modified T cells that we use for therapy, we followed the fate and function of individually sorted CAR-modified T cell subsets after activation with CD3 and CD28 Abs (CD3/28), transduction and culture alone, or after reconstitution into the relevant subset-depleted population. We show that all subsets are sensitive to CAR transduction, and each developed a distinct T cell functional profile during culture. Naive-derived T cells showed the greatest rate of proliferation but had more limited effector functions and reduced killing compared with memory-derived populations. When cultured in the presence of memory T cells, naive-derived T cells show increased differentiation, reduced effector cytokine production, and a reduced reproliferative response to CAR stimulation. CD3/28-activated T cells expanded in IL-7 and IL-15 produced greater expansion of memory stem T cells and central memory T cell-derived T cells compared with IL-2. Our strategy provides a powerful tool to elucidate the characteristics of CAR-modified T cells, regardless of the protocol used for expansion, reveals the functional properties of each expanded T cell subset, and paves the way for a more detailed evaluation of the effects of manufacturing changes on the subset contribution to in vitro-expanded T cells. Copyright © 2017 by The American Association of Immunologists, Inc.

  1. Cysteine desulfurase IscS2 plays a role in oxygen resistance in Clostridium difficile.

    Science.gov (United States)

    Giordano, Nicole; Hastie, Jessica L; Smith, Ashley D; Foss, Elissa D; Gutierrez-Munoz, Daniela F; Carlson, Paul E

    2018-06-04

    Clostridium difficile is an anaerobic, spore-forming bacterium capable of colonizing the gastrointestinal tract of humans following disruption of the normal microbiota, typically from antibiotic therapy for an unrelated infection. With approximately 500,000 confirmed infections leading to 29,000 deaths per year in the United States, C. difficile infection (CDI) is an urgent public health threat. We previously determined C. difficile survives in up to 3% oxygen. Low levels of oxygen are present in the intestinal tract with the higher concentrations being associated with the epithelial cell surface. Additionally, antibiotic treatment, the greatest risk factor for CDI, increases intestinal oxygen concentration. Therefore, we hypothesized that the C. difficile genome encodes mechanisms for survival during oxidative stress. Previous data have shown that cysteine desulfurases involved in iron-sulfur cluster assembly are involved in protecting bacteria from oxidative stress. In this study, deletion of a putative cysteine desulfurase ( Cd 630_12790/IscS2) involved in the iron sulfur cluster (Isc) system caused a severe growth defect in the presence of 2% oxygen. Additionally, this mutant delayed colonization in a conventional mouse model of CDI, and failed to colonize in a germ-free model, which has higher intestinal oxygen levels. These data imply an undefined role for this cysteine desulfurase in protecting C. difficile from low levels of oxygen in the gut. This is a work of the U.S. Government and is not subject to copyright protection in the United States. Foreign copyrights may apply.

  2. NOx emissions from high swirl turbulent spray flames with highly oxygenated fuels

    KAUST Repository

    Bohon, Myles

    2013-01-01

    Combustion of fuels with fuel bound oxygen is of interest from both a practical and a fundamental viewpoint. While a great deal of work has been done studying the effect of oxygenated additives in diesel and gasoline engines, much less has been done examining combustion characteristics of fuels with extremely high mass fractions of fuel bound oxygen. This work presents an initial investigation into the very low NOx emissions resulting from the combustion of a model, high oxygen mass fraction fuel. Glycerol was chosen as a model fuel with a fuel bound oxygen mass fraction of 52%, and was compared with emissions measured from diesel combustion at similar conditions in a high swirl turbulent spray flame. This work has shown that high fuel bound oxygen mass fractions allow for combustion at low global equivalence ratios with comparable exhaust gas temperatures due to the significantly lower concentrations of diluting nitrogen. Despite similar exhaust gas temperatures, NOx emissions from glycerol combustion were up to an order of magnitude lower than those measured using diesel fuel. This is shown to be a result not of specific burner geometry, but rather is influenced by the presence of higher oxygen and lower nitrogen concentrations at the flame front inhibiting NOx production. © 2012 The Combustion Institute.

  3. A gravimetric method for the determination of oxygen in uranium oxides and ternary uranium oxides by addition of alkaline earth compounds

    International Nuclear Information System (INIS)

    Fujino, Takeo; Tagawa, Hiroaki; Adachi, Takeo; Hashitani, Hiroshi

    1978-01-01

    A simple gravimetric determination of oxygen in uranium oxides and ternary uranium oxides is described. In alkaline earth uranates which are formed by heating in air at 800-1100 0 C, uranium is in the hexavalent state over certain continuous ranges of alkaline earth-to-uranium ratios. Thus, if an alkaline earth uranate or a compound containing an alkaline earth element, e.g. MgO, is mixed with the oxide sample and heated in air under suitable conditions, oxygen can be determined from the weight change before and after the reaction. The standard deviation of the O:U ratio for a UOsub(2+x) test sample is +-0.0008-0.001, if a correction is applied for atmospheric moisture absorbed during mixing. (Auth.)

  4. Oxygen transfer rate during the production of alginate by Azotobacter vinelandii under oxygen-limited and non oxygen-limited conditions

    Directory of Open Access Journals (Sweden)

    Peña Carlos F

    2011-02-01

    Full Text Available Abstract Background The oxygen transfer rate (OTR and dissolved oxygen tension (DOT play an important role in determining alginate production and its composition; however, no systematic study has been reported about the independent influence of the OTR and DOT. In this paper, we report a study about alginate production and the evolution of the molecular mass of the polymer produced by a wild-type A. vinelandii strain ATCC 9046, in terms of the maximum oxygen transfer rate (OTRmax in cultures where the dissolved oxygen tension (DOT was kept constant. Results The results revealed that in the two dissolved oxygen conditions evaluated, strictly controlled by gas blending at 0.5 and 5% DOT, an increase in the agitation rate (from 300 to 700 rpm caused a significant increase in the OTRmax (from 17 to 100 mmol L-1 h-1 for DOT of 5% and from 6 to 70 mmol L-1 h-1 for DOT of 0.5%. This increase in the OTRmax improved alginate production, as well as the specific alginate production rate (SAPR, reaching a maximal alginate concentration of 3.1 g L-1 and a SAPR of 0.031 g alg g biom-1 h-1 in the cultures at OTRmax of 100 mmol L-1 h-1. In contrast, the mean molecular mass (MMM of the alginate isolated from cultures developed under non-oxygen limited conditions increased by decreasing the OTRmax, reaching a maximal of 550 kDa at an OTRmax of 17 mmol L-1 h-1 . However, in the cultures developed under oxygen limitation (0.5% DOT, the MMM of the polymer was practically the same (around 200 kDa at 300 and 700 rpm, and this remained constant throughout the cultivation. Conclusions Overall, our results showed that under oxygen-limited and non oxygen-limited conditions, alginate production and its molecular mass are linked to the OTRmax, independently of the DOT of the culture.

  5. Oxygen potential of Th1-yUyO2+x

    International Nuclear Information System (INIS)

    Schram, R.P.C.; Cordfunke, E.H.P.

    1996-03-01

    Oxygen potentials of UO 2 -ThO 2 solid solutions (Th 1-y U y O 2+x ) were retrieved from literature and stored in a database. For each datapoint the oxygen pressure p O 2 the nonstoichiometry x, the temperature T and the uranium concentration y was specified. The data were analyzed using a defect model, which includes electronic disorder, point defects and cluster formation. In addition, the thermochemical representation of Lindemer and Besmann for UO 2+x was extended for the analysis of the Th 1-y U y O 2+x data. The solid solution is regarded as an ideal ternary mixture of UO 2 , ThO 2 and a hypothetical compound U a O b . The thermodynamic properties of this compound U a O b were determined in two oxygen pressure ranges of the database. In both the defect model and thermochemical approach ThO 2 is treated as an inert compound that does not participate in any of the chemical equilibria describing the oxygen potential. (orig.)

  6. Oxidative stress under ambient and physiological oxygen tension in tissue culture

    Science.gov (United States)

    Jagannathan, Lakshmanan; Cuddapah, Suresh; Costa, Max

    2016-01-01

    Oxygen (O2) levels range from 2–9% in vivo. However, cell culture experiments are performed at atmospheric O2 levels (21%). Oxidative stress due to generation of reactive oxygen species (ROS) in cells cultured at higher than physiological levels is implicated in multitude of deleterious effects including DNA damage, genomic instability and senescence. In addition, oxidative stress activates redox sensitive transcription factors related to inflammatory signaling and apoptotic signaling. Furthermore, several chromatin-modifying enzymes are affected by ROS, potentially impacting epigenetic regulation of gene expression. While primary cells are cultured at lower O2 levels due to their inability to grow at higher O2, the immortalized cells, which display no such apparent growth difficulties, are typically cultured at 21% O2. This review will provide an overview of issues associated with increased oxygen levels in in vitro cell culture and point out the benefits of using lower levels of oxygen tension even for immortalized cells. PMID:27034917

  7. Effect of ship locking on sediment oxygen uptake in impounded rivers

    DEFF Research Database (Denmark)

    Lorke, A.; McGinnis, D. F.; Maeck, A.

    2012-01-01

    In the majority of large river systems, flow is regulated and/or otherwise affected by operational and management activities, such as ship locking. The effect of lock operation on sediment-water oxygen fluxes was studied within a 12.9 km long impoundment at the Saar River (Germany) using eddy....... Additional means by which the oxygen budget of the impoundment is affected by lock-induced flow variations are discussed. Citation: Lorke, A., D. F. McGinnis, A. Maeck, and H. Fischer (2012), Effect of ship locking on sediment oxygen uptake in impounded rivers, Water Resour. Res., 48, W12514, doi: 10....... These wave-induced flow variations cause variations in sediment-water oxygen fluxes. While the mean flux during time periods without lock operation was 0.5 +/- 0.1 g m(-2) d(-1), it increased by about a factor of 2 to 1.0 +/- 0.5 g m(-2) d(-1) within time periods with ship locking. Following the daily...

  8. Variations in alveolar partial pressure for carbon dioxide and oxygen have additive not synergistic acute effects on human pulmonary vasoconstriction.

    Science.gov (United States)

    Croft, Quentin P P; Formenti, Federico; Talbot, Nick P; Lunn, Daniel; Robbins, Peter A; Dorrington, Keith L

    2013-01-01

    The human pulmonary vasculature constricts in response to hypercapnia and hypoxia, with important consequences for homeostasis and adaptation. One function of these responses is to direct blood flow away from poorly-ventilated regions of the lung. In humans it is not known whether the stimuli of hypercapnia and hypoxia constrict the pulmonary blood vessels independently of each other or whether they act synergistically, such that the combination of hypercapnia and hypoxia is more effective than the sum of the responses to each stimulus on its own. We independently controlled the alveolar partial pressures of carbon dioxide (Paco 2) and oxygen (Pao 2) to examine their possible interaction on human pulmonary vasoconstriction. Nine volunteers each experienced sixteen possible combinations of four levels of Paco 2 (+6, +1, -4 and -9 mmHg, relative to baseline) with four levels of Pao 2 (175, 100, 75 and 50 mmHg). During each of these sixteen protocols Doppler echocardiography was used to evaluate cardiac output and systolic tricuspid pressure gradient, an index of pulmonary vasoconstriction. The degree of constriction varied linearly with both Paco 2 and the calculated haemoglobin oxygen desaturation (1-So2). Mixed effects modelling delivered coefficients defining the interdependence of cardiac output, systolic tricuspid pressure gradient, ventilation, Paco 2 and So2. No interaction was observed in the effects on pulmonary vasoconstriction of carbon dioxide and oxygen (p>0.64). Direct effects of the alveolar gases on systolic tricuspid pressure gradient greatly exceeded indirect effects arising from concurrent changes in cardiac output.

  9. Oxygen Optode Sensors: Principle, Characterization, Calibration, and Application in the Ocean

    Directory of Open Access Journals (Sweden)

    Henry C. Bittig

    2018-01-01

    Full Text Available Recently, measurements of oxygen concentration in the ocean—one of the most classical parameters in chemical oceanography—are experiencing a revival. This is not surprising, given the key role of oxygen for assessing the status of the marine carbon cycle and feeling the pulse of the biological pump. The revival, however, has to a large extent been driven by the availability of robust optical oxygen sensors and their painstakingly thorough characterization. For autonomous observations, oxygen optodes are the sensors of choice: They are used abundantly on Biogeochemical-Argo floats, gliders and other autonomous oceanographic observation platforms. Still, data quality and accuracy are often suboptimal, in some part because sensor and data treatment are not always straightforward and/or sensor characteristics are not adequately taken into account. Here, we want to summarize the current knowledge about oxygen optodes, their working principle as well as their behavior with respect to oxygen, temperature, hydrostatic pressure, and response time. The focus will lie on the most widely used and accepted optodes made by Aanderaa and Sea-Bird. We revisit the essentials and caveats of in-situ in air calibration as well as of time response correction for profiling applications, and provide requirements for a successful field deployment. In addition, all required steps to post-correct oxygen optode data will be discussed. We hope this summary will serve as a comprehensive, yet concise reference to help people get started with oxygen observations, ensure successful sensor deployments and acquisition of highest quality data, and facilitate post-treatment of oxygen data. In the end, we hope that this will lead to more and higher-quality oxygen observations and help to advance our understanding of ocean biogeochemistry in a changing ocean.

  10. 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

  11. Integrin αMβ2 is differently expressed by subsets of human osteoclast precursors and mediates adhesion of classical monocytes to bone

    Energy Technology Data Exchange (ETDEWEB)

    Sprangers, Sara, E-mail: s.l.sprangers@acta.nl [Department of Oral Cell Biology and Functional Anatomy, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam, MOVE Research Institute Amsterdam, Gustav Mahlerlaan 3004, 1081 LA Amsterdam The Netherlands (Netherlands); Schoenmaker, Ton, E-mail: t.schoenmaker@acta.nl [Department of Oral Cell Biology and Functional Anatomy, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam, MOVE Research Institute Amsterdam, Gustav Mahlerlaan 3004, 1081 LA Amsterdam The Netherlands (Netherlands); Department of Periodontology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam, MOVE Research Institute Amsterdam, Gustav Mahlerlaan 3004, 1081 LA Amsterdam The Netherlands (Netherlands); Cao, Yixuan, E-mail: y.cao@acta.nl [Department of Oral Cell Biology and Functional Anatomy, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam, MOVE Research Institute Amsterdam, Gustav Mahlerlaan 3004, 1081 LA Amsterdam The Netherlands (Netherlands); Everts, Vincent, E-mail: v.everts@acta.nl [Department of Oral Cell Biology and Functional Anatomy, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam, MOVE Research Institute Amsterdam, Gustav Mahlerlaan 3004, 1081 LA Amsterdam The Netherlands (Netherlands); Vries, Teun J. de, E-mail: teun.devries@acta.nl [Department of Oral Cell Biology and Functional Anatomy, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam, MOVE Research Institute Amsterdam, Gustav Mahlerlaan 3004, 1081 LA Amsterdam The Netherlands (Netherlands); Department of Periodontology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam, MOVE Research Institute Amsterdam, Gustav Mahlerlaan 3004, 1081 LA Amsterdam The Netherlands (Netherlands)

    2017-01-01

    Bone-degrading osteoclasts are formed through fusion of their monocytic precursors. In the population of human peripheral blood monocytes, three distinct subsets have been identified: classical, intermediate and non-classical monocytes. We have previously shown that when the monocyte subsets are cultured on bone, significantly more osteoclasts are formed from classical monocytes than from intermediate or non-classical monocytes. Considering that this difference does not exist when monocyte subsets are cultured on plastic, we hypothesized that classical monocytes adhere better to the bone surface compared to intermediate and non-classical monocytes. To investigate this, the different monocyte subsets were isolated from human peripheral blood and cultured on slices of human bone in the presence of the cytokine M-CSF. We found that classical monocytes adhere better to bone due to a higher expression of the integrin αMβ2 and that their ability to attach to bone is significantly decreased when the integrin is blocked. This suggests that integrin αMβ2 mediates attachment of osteoclast precursors to bone and thereby enables the formation of osteoclasts.

  12. A theoretical model for oxygen transport in skeletal muscle under conditions of high oxygen demand.

    Science.gov (United States)

    McGuire, B J; Secomb, T W

    2001-11-01

    Oxygen transport from capillaries to exercising skeletal muscle is studied by use of a Krogh-type cylinder model. The goal is to predict oxygen consumption under conditions of high demand, on the basis of a consideration of transport processes occurring at the microvascular level. Effects of the decline in oxygen content of blood flowing along capillaries, intravascular resistance to oxygen diffusion, and myoglobin-facilitated diffusion are included. Parameter values are based on human skeletal muscle. The dependence of oxygen consumption on oxygen demand, perfusion, and capillary density are examined. When demand is moderate, the tissue is well oxygenated and consumption is slightly less than demand. When demand is high, capillary oxygen content declines rapidly with axial distance and radial oxygen transport is limited by diffusion resistance within the capillary and the tissue. Under these conditions, much of the tissue is hypoxic, consumption is substantially less than demand, and consumption is strongly dependent on capillary density. Predicted consumption rates are comparable with experimentally observed maximal rates of oxygen consumption.

  13. A latitudinal study of oxygen isotopes within horsehair

    Science.gov (United States)

    Thompson, E.; Bronk Ramsey, C.; McConnell, J. R.

    2016-12-01

    This study aims to explore the hypothesis that 'if oxygen isotope ratios deplete with decreasing temperature then a study of oxygen isotope ratios within horsehair from Oxfordshire to Iceland will show a latitudinal depletion gradient'. By looking at oxygen isotope values at different geographical positions, we can track the relationship with latitude and with different regional climate features. This will provide a firmer understanding of how to compare climate records from different locations. Additionally, a comparison of the horse breeds from this study to those analysed within previous studies will create an even better understanding of the intra-species variation within the δ18O values of horsehair. A total of 24 horses were sampled on the 7th March from Thordale Stud in Shetland, the Icelandic Food And Veterinary Authority in Iceland, the Exmoor Pony Centre in Exmoor and the Pigeon House Equestrian Centre in Oxfordshire. By starting the sampling process from the most recent growth at the follicle, the sampling date becomes a chronological marker, temporally fixing the first sample within a sequential set of data points extending for one year or longer, depending on the length of each individual hair. The samples were analysed for oxygen isotope values using an IRMS coupled within a Sercon HTEA. Preliminary results show a latitudinal gradient is evident on comparison between the locations, consistent with the findings of Darling and Talbot's study of fresh water isotopes in the British Isles (2003). These results support the hypothesis, showing that a study of oxygen isotope ratios within horse hair from Oxfordshire to Iceland showing a latitudinal depletion gradient, consistent with a depletion of oxygen isotope ratios due to decreasing temperatures. Darling, W. and Talbot, J. (2003). The O and H stable isotope composition of freshwaters in the British Isles. 1. Rainfall. Hydrol. Earth System Science, 7(2), pp.163-181.

  14. Oxygen-transfer performance of a newly designed, very low-volume membrane oxygenator.

    Science.gov (United States)

    Burn, Felice; Ciocan, Sorin; Carmona, Natalia Mendez; Berner, Marion; Sourdon, Joevin; Carrel, Thierry P; Tevaearai Stahel, Hendrik T; Longnus, Sarah L

    2015-09-01

    Oxygenation of blood and other physiological solutions are routinely required in fundamental research for both in vitro and in vivo experimentation. However, very few oxygenators with suitable priming volumes (parallel-oriented microporous polypropylene hollow fibres, placed inside a hollow shell with a lateral-luer outlet, and sealed at both extremities. With this design, perfusate is delivered via the core-tube to the centre of the mini-oxygenator, and exits via the luer port. A series of mini-oxygenators were constructed and tested in an in vitro perfusion circuit by monitoring oxygen transfer using modified Krebs-Henseleit buffer or whole porcine blood. Effects of perfusion pressure and temperature over flows of 5-60 ml × min(-1) were assessed. Twelve mini-oxygenators with a mean priming volume of 1.5 ± 0.3 ml were evaluated. With buffer, oxygen transfer reached a maximum of 14.8 ± 1.0 ml O2 × l(-1) (pO2: 450 ± 32 mmHg) at perfusate flow rates of 5 ml × min(-1) and decreased with an increase in perfusate flow to 7.8 ± 0.7 ml ml O2 × l(-1) (pO2: 219 ± 24 mmHg) at 60 ml × min(-1). Similarly, with blood perfusate, oxygen transfer also decreased as perfusate flow increased, ranging from 33 ± 5 ml O2 × l(-1) at 5 ml × min(-1) to 11 ± 2 ml O2 × l(-1) at 60 ml × min(-1). Furthermore, oxygen transfer capacity remained stable with blood perfusion over a period of at least 2 h. We have developed a new miniaturized membrane oxygenator with an ultra-low priming volume (circuits, such as small animal extracorporeal circulation and ex vivo organ perfusion. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  15. Zirconium metal-water oxidation kinetics. III. Oxygen diffusion in oxide and alpha Zircaloy phases

    International Nuclear Information System (INIS)

    Pawel, R.E.

    1976-10-01

    The reaction of Zircaloy in steam at elevated temperature involves the growth of discrete layers of oxide and oxygen-rich alpha Zircaloy from the parent beta phase. The multiphase, moving boundary diffusion problem involved is encountered in a number of important reaction schemes in addition to that of Zircaloy-oxygen and can be completely (albeitly ideally) characterized through an appropriate model in terms of oxygen diffusion coefficients and equilibrium concentrations for the various phases. Conversely, kinetic data for phase growth and total oxygen consumption rates can be used to compute diffusion coefficients. Equations are developed that express the oxygen diffusion coefficients in the oxide and alpha phases in terms of the reaction rate constants and equilibrium solubility values. These equations were applied to recent experimental kinetic data on the steam oxidation of Zircaloy-4 to determine the effective oxygen diffusion coefficients in these phases over the temperature range 1000--1500 0 C

  16. Effect of dissolved oxygen on biological denitrification using biodegradable plastic as the carbon source

    Science.gov (United States)

    Zhang, Xucai; Zhang, Jianmei

    2018-02-01

    Biological denitrification is currently a common approach to remove nitrate from wastewater. This study was conducted to evaluate the influence of dissolved oxygen on denitrification in wastewater treatment using biodegradable plastic as carbon source by designing the aerated, anoxic, and low-oxygen experimental treatment groups. The results showed that the removal rates of nitrate in anoxic and low-oxygen groups were 30.6 g NO3 --Nm-3 d-1 and 30.8 g NO3 --N m-3 d-1 at 83 h, respectively, both of which were higher than that of the aerated group. There was no significant difference between the anoxic and low-oxygen treatment groups for the nitrate removal. Additional, the nitrite accumulated during the experiments, and the nitrite concentrations in anoxic and aerated groups were lower than those in low-oxygen group. No nitrite was detected in all groups at the end of the experiments. These findings indicated that dissolved oxygen has important influence on denitrification, and anoxic and low-oxygen conditions can support completely denitrification when using BP as carbon source in nitrate-polluted wastewater treatment.

  17. Oxygen-carbon nanotubes as a chemotherapy sensitizer for paclitaxel in breast cancer treatment.

    Directory of Open Access Journals (Sweden)

    Yongkun Wang

    Full Text Available To study the in vivo and in vitro effects of adding oxygen carbon nanotubes (CNTs to chemotherapy for breast cancer.MCF-7 and SK-BR-3 breast cancer cells were co-cultured with paclitaxel and then exposed to oxygen-CNTs under hypoxic conditions. Cell proliferation, viability, and apoptosis rate were analyzed. Hypoxia-inducible factor-1 alpha (HIF-1α expression was measured using reverse transcription-polymerase chain reaction (RT-PCR and western blot. Nude mice were used as a human breast cancer model to explore the impact of oxygen-CNTs on the in vivo chemotherapeutic effect of paclitaxel.Oxygen-CNTs had no significant effects on the growth of breast cancer cells under normoxia and hypoxia. However, in the hypoxic environment, oxygen-CNTs significantly enhanced the inhibitory effect of paclitaxel on cell proliferation, as well as the apoptosis rate. Under hypoxia, downregulation of HIF-1α and upregulation of caspase-3, caspase-8, caspase-9, LC3 and Beclin-1 were observed when paclitaxel was combined with oxygen-CNT. Furthermore, addition of oxygen-CNTs to chemotherapy was found to significantly reduce tumor weight in the tumor-bearing mice model.Oxygen-CNTs can significantly increase the chemotherapeutic effect of paclitaxel on breast cancer cells. Oxygen-CNTs may be a potential chemosensitizer in breast cancer therapy.

  18. Time-dependent migration of citations through PubMed and OvidSP subsets: a study on a series of simultaneous PubMed and OvidSP searches.

    Science.gov (United States)

    Boeker, Martin; Vach, Werner; Motschall, Edith

    2013-01-01

    To quantitatively describe (1) differences between search results derived at consecutive time points with the PubMed and OvidSP literature search interfaces over a five day interval, and (2) the migration of citations through different subsets to estimate the timeliness of OvidSP. PubMed-Identifiers (PMIDs) of the following subsets were retrieved from PubMed and OvidSP simultaneously (within 8 h) at 11 days in March and April 2010 including 5 consecutive days: as supplied by publisher, in process, PubMed not MEDLINE, and OLDMEDLINE. Search results were compared for difference and intersection sets. The migration of citations on individual level was determined by comparison of corresponding sets over several days. The "in process" set was stable with about 446,000 - 452,000 citations; a small fraction of up to 3 % of the total subsets were in PubMed only and OvidSP only subsets. About 96 % of the ca. 10,500 citations in the OvidSP only subset migrated within 2 days out of the "in process" subset. The database of OvidSP is updated within a period of two days.

  19. The CD8⁺ memory stem T cell (T(SCM)) subset is associated with improved prognosis in chronic HIV-1 infection.

    Science.gov (United States)

    Ribeiro, Susan P; Milush, Jeffrey M; Cunha-Neto, Edecio; Kallas, Esper G; Kalil, Jorge; Somsouk, Ma; Hunt, Peter W; Deeks, Steven G; Nixon, Douglas F; SenGupta, Devi

    2014-12-01

    Memory stem T cells (T(SCM)) constitute a long-lived, self-renewing lymphocyte population essential for the maintenance of functional immunity. The hallmarks of HIV-1 pathogenesis are CD4(+) T cell depletion and abnormal cellular activation. We investigated the impact of HIV-1 infection on the T(SCM) compartment, as well as any protective role these cells may have in disease progression, by characterizing this subset in a cohort of 113 subjects with various degrees of viral control on and off highly active antiretroviral therapy (HAART). We observed that the frequency of CD8(+) T(SCM) was decreased in all individuals with chronic, untreated HIV-1 infection and that HAART had a restorative effect on this subset. In contrast, natural controllers of HIV-1 had the highest absolute number of CD4(+) T(SCM) cells among all of the infected groups. The frequency of CD4(+) T(SCM) predicted higher CD8(+) T(SCM) frequencies, consistent with a role for the CD4(+) subset in helping to maintain CD8(+) memory T cells. In addition, T(SCM) appeared to be progenitors for effector T cells (TEM), as these two compartments were inversely correlated. Increased frequencies of CD8(+) T(SCM) predicted lower viral loads, higher CD4(+) counts, and less CD8(+) T cell activation. Finally, we found that T(SCM) express the mucosal homing integrin α4β7 and can be identified in gut-associated lymphoid tissue (GALT). The frequency of mucosal CD4(+) T(SCM) was inversely correlated with that in the blood, potentially reflecting the ability of these self-renewing cells to migrate to a crucial site of ongoing viral replication and CD4(+) T cell depletion. HIV-1 infection leads to profound impairment of the immune system. T(SCM) constitute a recently identified lymphocyte subset with stem cell-like qualities, including the ability to generate other memory T cell subtypes, and are therefore likely to play an important role in controlling viral infection. We investigated the relationship between the size

  20. Carbon mineralization and oxygen dynamics in sediments with deep oxygen penetration, Lake Superior

    DEFF Research Database (Denmark)

    Li, Jiying; Crowe, Sean Andrew; Miklesh, David

    2012-01-01

    To understand carbon and oxygen dynamics in sediments with deep oxygen penetration, we investigated eight locations (160–318-m depth) throughout Lake Superior. Despite the 2–4 weight percent organic carbon content, oxygen penetrated into the sediment by 3.5 to > 12 cm at all locations. Such deep ...... volume-specific carbon degradation rates were 0.3–1.5 µmol cm−3 d−1; bioturbation coefficient near the sediment surface was 3–8 cm2 yr−1. These results indicate that carbon cycling in large freshwater systems conforms to many of the same trends as in marine systems.......To understand carbon and oxygen dynamics in sediments with deep oxygen penetration, we investigated eight locations (160–318-m depth) throughout Lake Superior. Despite the 2–4 weight percent organic carbon content, oxygen penetrated into the sediment by 3.5 to > 12 cm at all locations. Such deep......, suggesting that temporal variability in deeply oxygenated sediments may be greater than previously acknowledged. The oxygen uptake rates (4.4–7.7 mmol m−2 d−1, average 6.1 mmol m−2 d−1) and carbon mineralization efficiency (∼ 90% of deposited carbon) were similar to those in marine hemipelagic and pelagic...

  1. Spatially monitoring oxygen level in 3D microfabricated cell culture systems using optical oxygen sensing beads.

    Science.gov (United States)

    Wang, Lin; Acosta, Miguel A; Leach, Jennie B; Carrier, Rebecca L

    2013-04-21

    Capability of measuring and monitoring local oxygen concentration at the single cell level (tens of microns scale) is often desirable but difficult to achieve in cell culture. In this study, biocompatible oxygen sensing beads were prepared and tested for their potential for real-time monitoring and mapping of local oxygen concentration in 3D micro-patterned cell culture systems. Each oxygen sensing bead is composed of a silica core loaded with both an oxygen sensitive Ru(Ph2phen3)Cl2 dye and oxygen insensitive Nile blue reference dye, and a poly-dimethylsiloxane (PDMS) shell rendering biocompatibility. Human intestinal epithelial Caco-2 cells were cultivated on a series of PDMS and type I collagen based substrates patterned with micro-well arrays for 3 or 7 days, and then brought into contact with oxygen sensing beads. Using an image analysis algorithm to convert florescence intensity of beads to partial oxygen pressure in the culture system, tens of microns-size oxygen sensing beads enabled the spatial measurement of local oxygen concentration in the microfabricated system. Results generally indicated lower oxygen level inside wells than on top of wells, and local oxygen level dependence on structural features of cell culture surfaces. Interestingly, chemical composition of cell culture substrates also appeared to affect oxygen level, with type-I collagen based cell culture systems having lower oxygen concentration compared to PDMS based cell culture systems. In general, results suggest that oxygen sensing beads can be utilized to achieve real-time and local monitoring of micro-environment oxygen level in 3D microfabricated cell culture systems.

  2. Impact of initial lipid content and oxygen supply on alcoholic fermentation in champagne-like musts.

    Science.gov (United States)

    Ochando, Thomas; Mouret, Jean-Roch; Humbert-Goffard, Anne; Sablayrolles, Jean-Marie; Farines, Vincent

    2017-08-01

    Available nitrogen, lipids, or oxygen are nutrients with major impact on the kinetics of winemaking fermentation. Assimilable nitrogen is usually the growth-limiting nutrient which availability determines the fermentation rate and therefore the fermentation duration. In some particular cases, as in Champagne, grape musts have high available nitrogen content and low turbidity, i.e., below 50 Nephelometric Turbidity Unit (NTU). In the case of low turbidity, the availability of lipids, particularly phytosterols, becomes limiting. In this situation, control of oxygenation, which is necessary for lipid synthesis by yeast, is particularly crucial during fermentation. To mimic and understand these situations, a synthetic medium simulating the average composition of a Champagne must was used. This medium contained phytosterol (mainly β-sitosterol) concentrations ranging from 0 to 8mg/L corresponding to turbidity between 10 and 90 NTU. Population reached during the stationary phase and the maximum fermentation rate are conditioned by the initial phytosterol concentration determining the amount of nitrogen consumption. An early loss of viability was observed when the lipid concentrations were very low. For example, the viability continuously decreased during the stationary phase to a final value of 50% for an initial phytosterol concentration of 1mg/L. In some fermentations, 10mg/L oxygen were added at the end of the growth phase to combine the effects of initial content of phytosterols in the musts and the de novo synthesis of ergosterol and unsaturated fatty acids induced by oxygen addition. Effect of oxygen supply on the fermentation kinetics was particularly significant for media with low phytosterol contents. For example, the maximum fermentation rate was increased by 1.4-fold and the fermentation time was 70h shorter with oxygen addition in the medium containing 2mg/L of phytosterols. As a consequence of the oxygen supply, for the media containing 3, 5 and 8mg/L of

  3. Oxygen evolution reaction catalysis

    Energy Technology Data Exchange (ETDEWEB)

    Haber, Joel A.; Jin, Jian; Xiang, Chengxiang; Gregoire, John M.; Jones, Ryan J.; Guevarra, Dan W.; Shinde, Aniketa A.

    2016-09-06

    An Oxygen Evolution Reaction (OER) catalyst includes a metal oxide that includes oxygen, cerium, and one or more second metals. In some instances, the cerium is 10 to 80 molar % of the metals in the metal oxide and/or the catalyst includes two or more second metals. The OER catalyst can be included in or on an electrode. The electrode can be arranged in an oxygen evolution system such that the Oxygen Evolution Reaction occurs at the electrode.

  4. Relating oxygen partial pressure, saturation and content: the haemoglobin-oxygen dissociation curve.

    Science.gov (United States)

    Collins, Julie-Ann; Rudenski, Aram; Gibson, John; Howard, Luke; O'Driscoll, Ronan

    2015-09-01

    The delivery of oxygen by arterial blood to the tissues of the body has a number of critical determinants including blood oxygen concentration (content), saturation (S O2 ) and partial pressure, haemoglobin concentration and cardiac output, including its distribution. The haemoglobin-oxygen dissociation curve, a graphical representation of the relationship between oxygen satur-ation and oxygen partial pressure helps us to understand some of the principles underpinning this process. Historically this curve was derived from very limited data based on blood samples from small numbers of healthy subjects which were manipulated in vitro and ultimately determined by equations such as those described by Severinghaus in 1979. In a study of 3524 clinical specimens, we found that this equation estimated the S O2 in blood from patients with normal pH and S O2 >70% with remarkable accuracy and, to our knowledge, this is the first large-scale validation of this equation using clinical samples. Oxygen saturation by pulse oximetry (S pO2 ) is nowadays the standard clinical method for assessing arterial oxygen saturation, providing a convenient, pain-free means of continuously assessing oxygenation, provided the interpreting clinician is aware of important limitations. The use of pulse oximetry reduces the need for arterial blood gas analysis (S aO2 ) as many patients who are not at risk of hypercapnic respiratory failure or metabolic acidosis and have acceptable S pO2 do not necessarily require blood gas analysis. While arterial sampling remains the gold-standard method of assessing ventilation and oxygenation, in those patients in whom blood gas analysis is indicated, arterialised capillary samples also have a valuable role in patient care. The clinical role of venous blood gases however remains less well defined.

  5. Relating oxygen partial pressure, saturation and content: the haemoglobin–oxygen dissociation curve

    Directory of Open Access Journals (Sweden)

    Julie-Ann Collins

    2015-09-01

    The delivery of oxygen by arterial blood to the tissues of the body has a number of critical determinants including blood oxygen concentration (content, saturation (SO2 and partial pressure, haemoglobin concentration and cardiac output, including its distribution. The haemoglobin–oxygen dissociation curve, a graphical representation of the relationship between oxygen satur­ation and oxygen partial pressure helps us to understand some of the principles underpinning this process. Historically this curve was derived from very limited data based on blood samples from small numbers of healthy subjects which were manipulated in vitro and ultimately determined by equations such as those described by Severinghaus in 1979. In a study of 3524 clinical specimens, we found that this equation estimated the SO2 in blood from patients with normal pH and SO2 >70% with remarkable accuracy and, to our knowledge, this is the first large-scale validation of this equation using clinical samples. Oxygen saturation by pulse oximetry (SpO2 is nowadays the standard clinical method for assessing arterial oxygen saturation, providing a convenient, pain-free means of continuously assessing oxygenation, provided the interpreting clinician is aware of important limitations. The use of pulse oximetry reduces the need for arterial blood gas analysis (SaO2 as many patients who are not at risk of hypercapnic respiratory failure or metabolic acidosis and have acceptable SpO2 do not necessarily require blood gas analysis. While arterial sampling remains the gold-standard method of assessing ventilation and oxygenation, in those patients in whom blood gas analysis is indicated, arterialised capillary samples also have a valuable role in patient care. The clinical role of venous blood gases however remains less well defined.

  6. Integrated turbomachine oxygen plant

    Science.gov (United States)

    Anand, Ashok Kumar; DePuy, Richard Anthony; Muthaiah, Veerappan

    2014-06-17

    An integrated turbomachine oxygen plant includes a turbomachine and an air separation unit. One or more compressor pathways flow compressed air from a compressor through one or more of a combustor and a turbine expander to cool the combustor and/or the turbine expander. An air separation unit is operably connected to the one or more compressor pathways and is configured to separate the compressed air into oxygen and oxygen-depleted air. A method of air separation in an integrated turbomachine oxygen plant includes compressing a flow of air in a compressor of a turbomachine. The compressed flow of air is flowed through one or more of a combustor and a turbine expander of the turbomachine to cool the combustor and/or the turbine expander. The compressed flow of air is directed to an air separation unit and is separated into oxygen and oxygen-depleted air.

  7. Two-photon NADH imaging exposes boundaries of oxygen diffusion in cortical vascular supply regions.

    Science.gov (United States)

    Kasischke, Karl A; Lambert, Elton M; Panepento, Ben; Sun, Anita; Gelbard, Harris A; Burgess, Robert W; Foster, Thomas H; Nedergaard, Maiken

    2011-01-01

    Oxygen transport imposes a possible constraint on the brain's ability to sustain variable metabolic demands, but oxygen diffusion in the cerebral cortex has not yet been observed directly. We show that concurrent two-photon fluorescence imaging of endogenous nicotinamide adenine dinucleotide (NADH) and the cortical microcirculation exposes well-defined boundaries of tissue oxygen diffusion in the mouse cortex. The NADH fluorescence increases rapidly over a narrow, very low pO(2) range with a p(50) of 3.4 ± 0.6 mm Hg, thereby establishing a nearly binary reporter of significant, metabolically limiting hypoxia. The transient cortical tissue boundaries of NADH fluorescence exhibit remarkably delineated geometrical patterns, which define the limits of tissue oxygen diffusion from the cortical microcirculation and bear a striking resemblance to the ideal Krogh tissue cylinder. The visualization of microvessels and their regional contribution to oxygen delivery establishes penetrating arterioles as major oxygen sources in addition to the capillary network and confirms the existence of cortical oxygen fields with steep microregional oxygen gradients. Thus, two-photon NADH imaging can be applied to expose vascular supply regions and to localize functionally relevant microregional cortical hypoxia with micrometer spatial resolution.

  8. Conceptual design of a lunar oxygen pilot plant Lunar Base Systems Study (LBSS) task 4.2

    Science.gov (United States)

    1988-01-01

    The primary objective was to develop conceptual designs of two pilot plants to produce oxygen from lunar materials. A lunar pilot plant will be used to generate engineering data necessary to support an optimum design of a larger scale production plant. Lunar oxygen would be of primary value as spacecraft propellant oxidizer. In addition, lunar oxygen would be useful for servicing nonregenerative fuel cell power systems, providing requirements for life support, and to make up oxygen losses from leakage and airlock cycling. Thirteen different lunar oxygen production methods are described. Hydrogen reduction of ilmenite and extraction of solar-wind hydrogen from bulk lunar soil were selected for conceptual design studies. Trades and sensitivity analyses were performed with these models.

  9. Effects of motexafin gadolinium on tumor oxygenation and cellular oxygen consumption

    International Nuclear Information System (INIS)

    Donnelly, E.T.; Liu, Y.; Rockwell, S.; Magda, D.

    2003-01-01

    Full text: Recent work in our laboratory showed that motexafin gadolinium (MGd, Xcytrin), a drug currently in Phase III clinical trials as an adjuvant to radiation therapy, modulates the oxygen tensions in EMT6 tumors. The median pO 2 increased from the control value of 1.5±0.4 mmHg to 7.4 ± 3.8 mmHg six hours after treatment with 40 μmol/kg MGd and the percentage of severely hypoxic readings in the tumors ( 7 plateau phase EMT6 cells in 3 mL Dulbecco's Modified Eagle's Medium supplemented with 10% dialyzed fetal bovine serum, which contains no ascorbic acid. In the absence of ascorbic acid, 100 μM MGd did not alter the cellular oxygen consumption rate for EMT6 cells significantly. Marked inhibition of cellular oxygen consumption was observed when cells were incubated with 100 μM MGd in medium supplemented with equimolar ascorbic acid (a 31.5% decrease in consumption was observed after 6 hours of treatment). The 5% mannitol vehicle solution with equimolar ascorbic acid had no discernible effect on cellular oxygen consumption. Ascorbic acid may facilitate cellular uptake of MGd via the intermediate formation of a MGd-oxalate complex. These studies suggest that changes in cellular oxygen consumption could contribute to the changes in tumor oxygenation seen after administration of MGd. These experiments were supported by Pharmacyclics and training grant T32CA09085 from the NIH (E.T.D.). We thank Dr. Raymond Russell for allowing us to use his oxygen electrode apparatus

  10. Blood Monocyte Subsets and Selected Cardiovascular Risk Markers in Rheumatoid Arthritis of Short Duration in relation to Disease Activity

    Directory of Open Access Journals (Sweden)

    Ewa Klimek

    2014-01-01

    Full Text Available Objectives. To evaluate blood monocyte subsets and functional monocyte properties in patients with rheumatoid arthritis (RA of short duration in the context of cardiovascular (CV risk and disease activity. Methods. We studied conventional markers of CV risk, intima media thickness (IMT, and blood monocyte subsets in 27 patients aged 41 ± 10 years with RA of short duration (median 12 months and 22 healthy controls. The RA subjects were divided into low (DAS28: 2.6–5.1 and high (DAS28 > 5.1 disease activity. Results. RA patients exhibited increased levels of intermediate (CD14++CD16+ monocytes with decreased CD45RA expression compared to controls, increased counts of classical (CD14++CD16− monocytes, and decreased percentages of nonclassical (CD14+CD16++ monocytes. Patients with high disease activity had lower HLA DR expression on classical monocytes compared to low disease activity patients. There were no differences in monocyte subsets between subjects with DAS > 5.1 and DAS ≤ 5.1. There were no significant intergroup differences in IMT and the majority of classical CV risk factors. Conclusions. Patients with RA of short duration show alteration in peripheral blood monocyte subsets despite the fact that there is no evidence of subclinical atherosclerosis. Disease activity assessed with DAS28 was associated with impaired functional properties but not with a shift in monocyte subpopulations.

  11. Effect of oxygen on the processes of ion beam synthesis of buried SiC layers in silicon

    International Nuclear Information System (INIS)

    Artamonov, V.V.; Valakh, M.Ya.; Klyuj, N.I.; Mel'nik, V.P.; Romanyuk, A.B.; Romanyuk, B.N.; Yukhimchuk, V.A.

    1998-01-01

    The properties of Si-structures with buried silicon carbide (SiC) layers created by high dose carbon implantation into Cz-Si or Fz-Si wafers followed by high-temperature annealing were studied by Raman and infrared spectroscopy. Effect of additional oxygen implantation on the peculiarities of SiC layer formation was also studied. It was shown that under the same implantation and post-implantation annealing conditions the buried SiC layers are more effectively formed in Cz-Si or in Si subjected to additional oxygen implantation. Thus, oxygen in silicon promotes the SiC layer formation due to SiO x precipitate creation and accommodation of the crystal volume in the region where SiC phase is formed

  12. Exhaustive Exercise-induced Oxidative Stress Alteration of Erythrocyte Oxygen Release Capacity.

    Science.gov (United States)

    Xiong, Yanlian; Xiong, Yanlei; Wang, Yueming; Zhao, Yajin; Li, Yaojin; Ren, Yang; Wang, Ruofeng; Zhao, Mingzi; Hao, Yitong; Liu, Haibei; Wang, Xiang

    2018-05-24

    The aim of the present study is to explore the effect of exhaustive running exercise (ERE) in the oxygen release capacity of rat erythrocytes. Rats were divided into sedentary control (C), moderate running exercise (MRE) and exhaustive running exercise groups. The thermodynamics and kinetics properties of the erythrocyte oxygen release process of different groups were tested. We also determined the degree of band-3 oxidative and phosphorylation, anion transport activity and carbonic anhydrase isoform II(CAII) activity. Biochemical studies suggested that exhaustive running significantly increased oxidative injury parameters in TBARS and methaemoglobin levels. Furthermore, exhaustive running significantly decreased anion transport activity and carbonic anhydrase isoform II(CAII) activity. Thermodynamic analysis indicated that erythrocytes oxygen release ability also significantly increased due to elevated 2,3-DPG level after exhaustive running. Kinetic analysis indicated that exhaustive running resulted in significantly decreased T50 value. We presented evidence that exhaustive running remarkably impacted thermodynamics and kinetics properties of RBCs oxygen release. In addition, changes in 2,3-DPG levels and band-3 oxidation and phosphorylation could be the driving force for exhaustive running induced alterations in erythrocytes oxygen release thermodynamics and kinetics properties.

  13. Rapid determination of oxygen saturation and vascularity for cancer detection.

    Directory of Open Access Journals (Sweden)

    Fangyao Hu

    Full Text Available A rapid heuristic ratiometric analysis for estimating tissue hemoglobin concentration and oxygen saturation from measured tissue diffuse reflectance spectra is presented. The analysis was validated in tissue-mimicking phantoms and applied to clinical measurements in head and neck, cervical and breast tissues. The analysis works in two steps. First, a linear equation that translates the ratio of the diffuse reflectance at 584 nm and 545 nm to estimate the tissue hemoglobin concentration using a Monte Carlo-based lookup table was developed. This equation is independent of tissue scattering and oxygen saturation. Second, the oxygen saturation was estimated using non-linear logistic equations that translate the ratio of the diffuse reflectance spectra at 539 nm to 545 nm into the tissue oxygen saturation. Correlations coefficients of 0.89 (0.86, 0.77 (0.71 and 0.69 (0.43 were obtained for the tissue hemoglobin concentration (oxygen saturation values extracted using the full spectral Monte Carlo and the ratiometric analysis, for clinical measurements in head and neck, breast and cervical tissues, respectively. The ratiometric analysis was more than 4000 times faster than the inverse Monte Carlo analysis for estimating tissue hemoglobin concentration and oxygen saturation in simulated phantom experiments. In addition, the discriminatory power of the two analyses was similar. These results show the potential of such empirical tools to rapidly estimate tissue hemoglobin in real-time spectral imaging applications.

  14. Chemical library subset selection algorithms: a unified derivation using spatial statistics.

    Science.gov (United States)

    Hamprecht, Fred A; Thiel, Walter; van Gunsteren, Wilfred F

    2002-01-01

    If similar compounds have similar activity, rational subset selection becomes superior to random selection in screening for pharmacological lead discovery programs. Traditional approaches to this experimental design problem fall into two classes: (i) a linear or quadratic response function is assumed (ii) some space filling criterion is optimized. The assumptions underlying the first approach are clear but not always defendable; the second approach yields more intuitive designs but lacks a clear theoretical foundation. We model activity in a bioassay as realization of a stochastic process and use the best linear unbiased estimator to construct spatial sampling designs that optimize the integrated mean square prediction error, the maximum mean square prediction error, or the entropy. We argue that our approach constitutes a unifying framework encompassing most proposed techniques as limiting cases and sheds light on their underlying assumptions. In particular, vector quantization is obtained, in dimensions up to eight, in the limiting case of very smooth response surfaces for the integrated mean square error criterion. Closest packing is obtained for very rough surfaces under the integrated mean square error and entropy criteria. We suggest to use either the integrated mean square prediction error or the entropy as optimization criteria rather than approximations thereof and propose a scheme for direct iterative minimization of the integrated mean square prediction error. Finally, we discuss how the quality of chemical descriptors manifests itself and clarify the assumptions underlying the selection of diverse or representative subsets.

  15. Shale-oil-derived additives for fuel oils

    International Nuclear Information System (INIS)

    Raidma, E.; Leetsman, L.; Muoni, R.; Soone, Y.; Zhiryakov, Y.

    2002-01-01

    Studies have shown that the oxidation, wearing, and anticorrosive properties of shale oil as an additive to liquid fuels and oils enable to improve the conditions of their use. Studies conducted by Institute of Oil Shale have shown that it is possible, on the basis of shale oil produced by Viru Keemia Grupp AS (Viru Chemistry Group Ltd.) and, particularly, on the basis of its fractions 230-320 and 320-360 deg C to produce efficient and stable additives for liquid fuels to improve their combustion and storage properties. In the production of additives from shale oil the prerequisite taken into account is its complexity of composition and high concentration of neutral and phenolic oxygen compounds. Additives produced from shale oil have multifunctional properties which enable to improve operational data of liquid fuels and to increase the power of diesel engines and boilers. (author)

  16. Internal-reference solid-electrolyte oxygen sensor

    International Nuclear Information System (INIS)

    Haaland, D.M.

    1977-01-01

    A new solid-electrolyte oxygen sensor has been developed that eliminates the conventional oxygen reference in previous solid-electrolyte oxygen sensor designs and is, therefore, ideally suited as an insertion device for remote oxygen monitoring applications. It is constructed with two cells of stabilized zirconia sealed into a small unit using a new high-temperature platinum-zirconia seal. One electrochemical cell monitors the ratio of oxygen partial pressures inside and outside the sensor while the other solid-electrolyte cell is used for quantitative electrochemical pumping of oxygen. The internal oxygen reference is generated by initially pumping all oxygen out of the known internal volume of the sensor and then quantitatively pumping oxygen back in until oxygen partial pressures are equal inside and out. This information is used with the ideal gas law to calculate oxygen partial pressures. Tests were conducted from 400 to 1000 0 C in mixtures of oxygen and nitrogen spanning approximately 0.2 to 21 percent oxygen concentration range. Sensors with sputtered platinum and porous platinum paste electrodes were compared

  17. Oxygen Tension in the Aqueous Humor of Human Eyes under Different Oxygenation Conditions

    Directory of Open Access Journals (Sweden)

    Farideh Sharifipour

    2013-01-01

    Full Text Available Purpose: To measure oxygen tension in the aqueous humor of human eyes under different oxygenation conditions. Methods: This prospective comparative interventional case series consisted of two parts. In the first part, 120 consecutive patients scheduled for cataract surgery were randomized into group I (control group in which surgery was performed under local anesthesia inhaling 21% oxygen; group II in whom general anesthesia using 50% oxygen was employed; and group III receiving general anesthesia with 100% oxygen. After aspirating 0.2 ml aqueous humor under sterile conditions, the aqueous sample and a simultaneously drawn arterial blood sample were immediately analyzed using a blood gas analyzer. In part II the same procedures were performed in 10 patients after fitting a contact lens and patching the eye for 20 minutes (group IV and in 10 patients after transcorneal delivery of oxygen at a flow rate of 5 L/min (group V. Results: Mean aqueous PO2 in groups I, II and III was 112.3±6.2, 141.1±20.4, and 170.1±27 mmHg, respectively (P values <0.001 and mean arterial PO2 was 85.7±7.9, 184.6±46, and 379.1±75.9 mmHg, respectively (P values <0.001. Aqueous PO2 was 77.2±9.2 mmHg in group IV and 152.3±10.9 mmHg in group V (P values <0.001. There was a significant correlation between aqueous and blood PO2 (r=0.537, P<0.001. The contribution of atmospheric oxygen to aqueous PO2 was 23.7%. Conclusion: Aqueous oxygen tension is mostly dependent on the systemic circulation and in part on the atmosphere. Increasing inspiratory oxygen and transcorneal oxygen delivery both increase aqueous PO2 levels.

  18. Oxygen carrying perfluorochemical emulsion as an adjuvant to radiation therapy

    International Nuclear Information System (INIS)

    Teicher, B.A.; Rose, C.M.

    1984-01-01

    The potential of a perfluorochemical emulsion which as an excellent carrying capacity for oxygen to enhance the ability of radiation therapy to delay the growth of Lewis lung tumor was examined. There was a highly significant effect produced by the addition of perfluorochemical emulsion and carbogen breathing in combination with irradiation. With single dose x-ray treatment the dose of perfluorochemical emulsion was varied from 0.05-0.6 ml addition to the blood volume of the animals. The dose response effect was very broad peaking at 0.3-0.4 ml which gave a dose modifying effect of 2.8 +- 0.6 with 1000 rad of x-rays. The addition of 0.3 ml of perfluorochemical free annex solution with carbogen breathing produced a small enhancement in tumor growth delay addition of the same volume of the complete emulsion increased the tumor growth delay time about 3-fold compared to the annex solution. When the perfluorochemical emulsion was added to a fractionated course of radiation therapy a dose modifying effect of 1.8 +- 0.3 was obtained. Oxygen carrying perfluorochemical emulsions may provide a nontoxic clinically useful means of increasing the effectiveness of radiation therapy and of certain chemotherapeutic agents

  19. Renal hemodynamics and oxygenation in transient renal artery occluded rats evaluated with iron-oxide particles and oxygenation-sensitive imaging

    International Nuclear Information System (INIS)

    Pedersen, Michael; Aarhus Univ.; Univ. Victor Segalen Bordeaux 2; Laustsen, Christoffer; Perot, Vincent; Grenier, Nicolas; Basseau, Fabrice; Moonen, Chrit

    2010-01-01

    Mild or severe renal arterial occlusion is a phenomenon occasionally observed in daily clinical practice, potentially leading to renal ischemia and a general impairment of renal function. Secondly, closing the blood flow to the kidneys can also occur during kidney transplantation procedures. However, the exact physiological effects of these conditions on renal blood perfusion as well as the renal oxygen handling are poorly understood. The objectives of this study were therefore to measure the lateral changes of renal blood perfusion in rats subjected to transient unilateral arterial occlusion (RAS), and in addition, to measure the consequences on the intrarenal oxygenation. Experimental studies were performed using sixteen adolescent rats. The left renal artery was exposed through a flank incision and acute RAS for 45 min was achieved by placing a ligature around the renal artery. MRI was performed 3 days after the surgical procedure, where a blood oxygenation sensitive sequence (BOLD MRI) was performed, followed by a perfusion-weighted imaging sequence using a single bolus of the iron-oxide nanoparticle Sinerem. The renal oxygenation of blood was indirectly measured by the BOLD-parameter R2 * , and perfusion measures include relative renal blood flow, relative renal blood volume and mean transit time. Histopathologic changes through the outer stripe of the outer medulla showing typical histopathologic findings of ischemia. This study demonstrated that rats with transient renal arterial stenosis (for 45 min) showed a reduction in intrarenal oxygenation and intrarenal blood flow three days after the surgical procedure. A decreased R2 * was measured within the ipsilateral medulla in parallel with a decreased medullary blood flow, is probably related to a lower reabsorption load within the ipsilateral kidney. MRI may therefore be a promising tool in long-term evaluation of RAS. (orig.)

  20. Renal hemodynamics and oxygenation in transient renal artery occluded rats evaluated with iron-oxide particles and oxygenation-sensitive imaging

    Energy Technology Data Exchange (ETDEWEB)

    Pedersen, Michael [Aarhus Univ. Hospital (Denmark). MR Research Centre; Aarhus Univ. (Denmark). Inst. of Experimental Clinical Medicine; Univ. Victor Segalen Bordeaux 2 (France). Lab. Imagerie Moleculaire et Fonctionnelle: de la physiologie a la therapie CNRS UMR 5231; Laustsen, Christoffer [Aarhus Univ. Hospital (Denmark). MR Research Centre; Perot, Vincent; Grenier, Nicolas [Hopital Pellegrin, CHU Bordeaux (France). Service d' Imagerie Diagnostique et Therapeutique de l' Adulte; Basseau, Fabrice; Moonen, Chrit [Univ. Victor Segalen Bordeaux 2 (France). Lab. Imagerie Moleculaire et Fonctionnelle: de la physiologie a la therapie CNRS UMR 5231

    2010-07-01

    Mild or severe renal arterial occlusion is a phenomenon occasionally observed in daily clinical practice, potentially leading to renal ischemia and a general impairment of renal function. Secondly, closing the blood flow to the kidneys can also occur during kidney transplantation procedures. However, the exact physiological effects of these conditions on renal blood perfusion as well as the renal oxygen handling are poorly understood. The objectives of this study were therefore to measure the lateral changes of renal blood perfusion in rats subjected to transient unilateral arterial occlusion (RAS), and in addition, to measure the consequences on the intrarenal oxygenation. Experimental studies were performed using sixteen adolescent rats. The left renal artery was exposed through a flank incision and acute RAS for 45 min was achieved by placing a ligature around the renal artery. MRI was performed 3 days after the surgical procedure, where a blood oxygenation sensitive sequence (BOLD MRI) was performed, followed by a perfusion-weighted imaging sequence using a single bolus of the iron-oxide nanoparticle Sinerem. The renal oxygenation of blood was indirectly measured by the BOLD-parameter R2{sup *}, and perfusion measures include relative renal blood flow, relative renal blood volume and mean transit time. Histopathologic changes through the outer stripe of the outer medulla showing typical histopathologic findings of ischemia. This study demonstrated that rats with transient renal arterial stenosis (for 45 min) showed a reduction in intrarenal oxygenation and intrarenal blood flow three days after the surgical procedure. A decreased R2{sup *} was measured within the ipsilateral medulla in parallel with a decreased medullary blood flow, is probably related to a lower reabsorption load within the ipsilateral kidney. MRI may therefore be a promising tool in long-term evaluation of RAS. (orig.)

  1. Effect of irradiation on human T-cell proliferation: low dose irradiation stimulates mitogen-induced proliferation and function of the suppressor/cytotoxic T-cell subset

    International Nuclear Information System (INIS)

    Gualde, N.; Goodwin, J.S.

    1984-01-01

    Unfractionated human T cells exposed to 10-50 rad of X irradiation incorporated less [ 3 H]thymidine than nonirradiated T cells when subsequently cultured with PHA or Con A. The cytotoxic/suppressor T-cell subset, isolated as either OKT8(+) or OKT4(-) cells, demonstrated significantly enhanced [ 3 H]thymidine incorporation in PHA- or Con A-stimulated cultures after exposure to 10-50 rad, compared to unirradiated cells, while the proliferation of the OKT4(+) helper/inducer subset was inhibited by low dose irradiation. It has been previously reported that approximately 30% of the cytotoxic/suppressor subset also stains with OKM1. When the cytotoxic/suppressor subset was further subdivided into OKT4(-), OKM1(+), and OKT4(-), OKM1(-) cells, proliferation of the OKT4(-), OKM1(+) population was inhibited by exposure to 25 rad while proliferation of the OKT4(-), OKM1(-) population was stimulated. The increase in proliferation of the cytotoxic/suppressor T-cell subset after low dose irradiation is paralleled by an increase in suppressor activity of these cells. T cells exposed to 25 rad and then cultured with Con A for 48 hr caused greater inhibition of IgG production when added to fresh autologous lymphocytes stimulated by pokeweed mitogen than did unirradiated cells. Thus, low dose irradiation enhances both the proliferation and function of the human suppressor T-cell subset

  2. A Low-Pressure Oxygen Storage System for Oxygen Supply in Low-Resource Settings.

    Science.gov (United States)

    Rassool, Roger P; Sobott, Bryn A; Peake, David J; Mutetire, Bagayana S; Moschovis, Peter P; Black, Jim Fp

    2017-12-01

    Widespread access to medical oxygen would reduce global pneumonia mortality. Oxygen concentrators are one proposed solution, but they have limitations, in particular vulnerability to electricity fluctuations and failure during blackouts. The low-pressure oxygen storage system addresses these limitations in low-resource settings. This study reports testing of the system in Melbourne, Australia, and nonclinical field testing in Mbarara, Uganda. The system included a power-conditioning unit, a standard oxygen concentrator, and an oxygen store. In Melbourne, pressure and flows were monitored during cycles of filling/emptying, with forced voltage fluctuations. The bladders were tested by increasing pressure until they ruptured. In Mbarara, the system was tested by accelerated cycles of filling/emptying and then run on grid power for 30 d. The low-pressure oxygen storage system performed well, including sustaining a pressure approximately twice the standard working pressure before rupture of the outer bag. Flow of 1.2 L/min was continuously maintained to a simulated patient during 30 d on grid power, despite power failures totaling 2.9% of the total time, with durations of 1-176 min (mean 36.2, median 18.5). The low-pressure oxygen storage system was robust and durable, with accelerated testing equivalent to at least 2 y of operation revealing no visible signs of imminent failure. Despite power cuts, the system continuously provided oxygen, equivalent to the treatment of one child, for 30 d under typical power conditions for sub-Saharan Africa. The low-pressure oxygen storage system is ready for clinical field trials. Copyright © 2017 by Daedalus Enterprises.

  3. Decline in arterial partial pressure of oxygen after exercise: a surrogate marker of pulmonary vascular obstructive disease in patients with atrial septal defect and severe pulmonary hypertension.

    Science.gov (United States)

    Laksmivenkateshiah, Srinivas; Singhi, Anil K; Vaidyanathan, Balu; Francis, Edwin; Karimassery, Sundaram R; Kumar, Raman K

    2011-06-01

    To examine the utility of decline in arterial partial pressure of oxygen after exercise as a marker of pulmonary vascular obstructive disease in patients with atrial septal defect and pulmonary hypertension. Treadmill exercise was performed in 18 patients with atrial septal defect and pulmonary hypertension. Arterial blood gas samples were obtained before and after peak exercise. A decline in the arterial pressure of oxygen of more than 10 millimetres of mercury after exercise was considered significant based on preliminary tests conducted on the controls. Cardiac catheterisation was performed in all patients and haemodynamic data sets were obtained on room air, oxygen, and a mixture of oxygen and nitric oxide (30-40 parts per million). There were 10 patients who had more than a 10 millimetres of mercury drop in arterial partial pressure of oxygen after exercise and who had a basal pulmonary vascular resistance index of more than 7 Wood units per square metre. Out of eight patients who had less than a 10 millimetres of mercury drop in arterial partial pressure of oxygen after exercise, seven had a basal pulmonary vascular resistance index of less than 7 Wood units per square metre, p equals 0.0001. A decline in arterial partial pressure of oxygen of more than 10 millimetres of mercury predicted a basal pulmonary vascular resistance index of more than 7 Wood units per square metre with a specificity of 100% and a sensitivity of 90%. A decline in arterial partial pressure of oxygen following exercise appears to predict a high pulmonary vascular resistance index in patients with atrial septal defect and pulmonary hypertension. This test is a useful non-invasive marker of pulmonary vascular obstructive disease in this subset.

  4. Dissolved oxygen concentration in the medium during cell culture: Defects and improvements.

    Science.gov (United States)

    Zhang, Kuan; Zhao, Tong; Huang, Xin; He, Yunlin; Zhou, Yanzhao; Wu, Liying; Wu, Kuiwu; Fan, Ming; Zhu, Lingling

    2016-03-01

    In vitro cell culture has provided a useful model to study the effects of oxygen on cellular behavior. However, it remains unknown whether the in vitro operations themselves affect the medium oxygen levels and the living states of cells. In addition, a prevailing controversy is whether reactive oxygen species (ROS) production is induced by continuous hypoxia or reoxygenation. In this study, we have measured the effects of different types of cell culture containers and the oxygen environment where medium replacement takes place on the actual oxygen tension in the medium. We found that the deviations of oxygen concentrations in the medium are much greater in 25-cm(2) flasks than in 24-well plates and 35-mm dishes. The dissolved oxygen concentrations in the medium were increased after medium replacement in normoxia, but remained unchanged in glove boxes in which the oxygen tension remained at a low level (11.4, 5.7, and 0.5% O2 ). We also found that medium replacement in normoxia increased the number of ROS-positive cells and reduced the cell viability; meanwhile, medium replacement in a glove box did not produce the above effects. Therefore, we conclude that the use of 25-cm(2) flasks should be avoided and demonstrate that continuous hypoxia does not produce ROS, whereas the reoxygenation that occurs during the harvesting of cells leads to ROS and induces cell death. © 2015 International Federation for Cell Biology.

  5. The limitations of tissue-oxygen measurement and positron emission tomography as additional methods for postoperative breast reconstruction free-flap monitoring.

    Science.gov (United States)

    Schrey, Aleksi; Niemi, Tarja; Kinnunen, Ilpo; Minn, Heikki; Vahlberg, Tero; Kalliokoski, Kari; Suominen, Erkki; Grénman, Reidar; Aitasalo, Kalle

    2010-02-01

    Twelve patients who underwent breast reconstruction with a microvascular flap were monitored postoperatively with continuous partial tissue oxygenation (p(ti)O(2)) measurement. The regional blood flow (BF) of the entire flap was evaluated with positron emission tomography (PET) using oxygen-15-labelled water on the first postoperative (POP) morning to achieve data of the perfusion of the entire flap. A re-exploration was carried out if the p(ti)O(2) value remained lower than 15 mmHg for over 30 min. The mean p(ti)O(2) value of the flaps was 52.9+/-5.5 mmHg, whereas the mean BF values were 3.3+/-1.0 ml per 100 g min(-1). One false-positive result was detected by p(ti)O(2) measurement, resulting in an unnecessary re-exploration. Another re-operation suggested by the low p(ti)O(2) results was avoided due to the normal BF results assessed with PET. Totally, three flaps were re-explored. This prospective study suggests that continuous tissue-oxygen measurement with a polarographic needle probe is reliable for monitoring free breast flaps from one part of the flap, but assessing perfusion of the entire flap requires more complex monitoring methods, for example, PET. Clinical examination by experienced personnel remains important in free-breast-flap monitoring. PET could be useful in assessing free-flap perfusion in selected high-risk patients as an alternative to a re-operation when clinical examination and evaluation by other means are unreliable or present controversial results. 2008 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  6. Exploratory subsetting of autism families based on savant skills improves evidence of genetic linkage to 15q11-q13.

    Science.gov (United States)

    Nurmi, Erika L; Dowd, Michael; Tadevosyan-Leyfer, Ovsanna; Haines, Jonathan L; Folstein, Susan E; Sutcliffe, James S

    2003-07-01

    Autism displays a remarkably high heritability but a complex genetic etiology. One approach to identifying susceptibility loci under these conditions is to define more homogeneous subsets of families on the basis of genetically relevant phenotypic or biological characteristics that vary from case to case. The authors performed a principal components analysis, using items from the Autism Diagnostic Interview, which resulted in six clusters of variables, five of which showed significant sib-sib correlation. The utility of these phenotypic subsets was tested in an exploratory genetic analysis of the autism candidate region on chromosome 15q11-q13. When the Collaborative Linkage Study of Autism sample was divided, on the basis of mean proband score for the "savant skills" cluster, the heterogeneity logarithm of the odds under a recessive model at D15S511, within the GABRB3 gene, increased from 0.6 to 2.6 in the subset of families in which probands had greater savant skills. These data are consistent with the genetic contribution of a 15q locus to autism susceptibility in a subset of affected individuals exhibiting savant skills. Similar types of skills have been noted in individuals with Prader-Willi syndrome, which results from deletions of this chromosomal region.

  7. Simultaneous sampling of tissue oxygenation and oxygen consumption in skeletal muscle.

    Science.gov (United States)

    Nugent, William H; Song, Bjorn K; Pittman, Roland N; Golub, Aleksander S

    2016-05-01

    Under physiologic conditions, microvascular oxygen delivery appears to be well matched to oxygen consumption in respiring tissues. We present a technique to measure interstitial oxygen tension (PISFO2) and oxygen consumption (VO2) under steady-state conditions, as well as during the transitions from rest to activity and back. Phosphorescence Quenching Microscopy (PQM) was employed with pneumatic compression cycling to achieve 1 to 10 Hz sampling rates of interstitial PO2 and simultaneous recurrent sampling of VO2 (3/min) in the exteriorized rat spinotrapezius muscle. The compression pressure was optimized to 120-130 mmHg without adverse effect on the tissue preparation. A cycle of 5s compression followed by 15s recovery yielded a resting VO2 of 0.98 ± 0.03 ml O2/100 cm(3)min while preserving microvascular oxygen delivery. The measurement system was then used to assess VO2 dependence on PISFO2 at rest and further tested under conditions of isometric muscle contraction to demonstrate a robust ability to monitor the on-kinetics of tissue respiration and the compensatory changes in PISFO2 during contraction and recovery. The temporal and spatial resolution of this approach is well suited to studies seeking to characterize microvascular oxygen supply and demand in thin tissues. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Kinetics of oxygen species in an electrically driven singlet oxygen generator

    International Nuclear Information System (INIS)

    Azyazov, V.N.; Torbin, A.P.; Pershin, A.A.; Mikheyev, P.A.; Heaven, M.C.

    2015-01-01

    Highlights: • Vibrational excitation of O_3 increases the rate constant for O_3 + O_2(a) → 2O_2(X) + O. • Vibrationally excited O_3 is produced by the O + O_2(X) + M → O_3 + M reaction. • Ozone concentrations are impacted by the reactions of vibrationally excited O_3. • Relevant to ozone concentrations in oxygen discharges and the upper atmosphere. - Abstract: The kinetics of oxygen species in the gaseous medium of a discharge singlet oxygen generator has been revisited. Vibrationally excited ozone O_3(υ) formed in O + O_2 recombination is thought to be a significant agent in the deactivation of singlet oxygen O_2(a"1Δ), oxygen atom removal and ozone formation. It is shown that the process O_3(υ ⩾ 2) + O_2(a"1Δ) → 2O_2 + O is the main O_2(a"1Δ) deactivation channel in the post-discharge zone. If no measures are taken to decrease the oxygen atom concentration, the contribution of this process to the overall O_2(a"1Δ) removal is significant, even in the discharge zone. A simplified model for the kinetics of vibrationally excited ozone is proposed. Calculations based on this model yield results that are in good agreement with the experimental data.

  9. Natural Ores as Oxygen Carriers in Chemical Looping Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Hanjing; Siriwardane, Ranjani; Simonyi, Thomas; Poston, James

    2013-08-01

    Chemical looping combustion (CLC) is a combustion technology that utilizes oxygen from oxygen carriers (OC), such as metal oxides, instead of air to combust fuels. The use of natural minerals as oxygen carriers has advantages, such as lower cost and availability. Eight materials, based on copper or iron oxides, were selected for screening tests of CLC processes using coal and methane as fuels. Thermogravimetric experiments and bench-scale fixed-bed reactor tests were conducted to investigate the oxygen transfer capacity, reaction kinetics, and stability during cyclic reduction/oxidation reaction. Most natural minerals showed lower combustion capacity than pure CuO/Fe{sub 2}O{sub 3} due to low-concentrations of active oxide species in minerals. In coal CLC, chryscolla (Cu-based), magnetite, and limonite (Fe-based) demonstrated better reaction performances than other materials. The addition of steam improved the coal CLC performance when using natural ores because of the steam gasification of coal and the subsequent reaction of gaseous fuels with active oxide species in the natural ores. In methane CLC, chryscolla, hematite, and limonite demonstrated excellent reactivity and stability in 50-cycle thermogravimetric analysis tests. Fe{sub 2}O{sub 3}-based ores possess greater oxygen utilization but require an activation period before achieving full performance in methane CLC. Particle agglomeration issues associated with the application of natural ores in CLC processes were also studied by scanning electron microscopy (SEM).

  10. Comparison Between the Acute Pulmonary Vascular Effects of Oxygen with Nitric Oxide and Sildenafil

    Directory of Open Access Journals (Sweden)

    Ronald W. Day

    2015-03-01

    Full Text Available Objective. Right heart catheterization is performed in patients with pulmonary arterial hypertension to determine the severity of disease and their pulmonary vascular reactivity. The acute pulmonary vascular effect of inhaled nitric oxide is frequently used to identify patients who will respond favorably to vasodilator therapy. This study sought to determine whether the acute pulmonary vascular effects of oxygen with nitric oxide and intravenous sildenafil are similar. Methods. A retrospective, descriptive study of 13 individuals with pulmonary hypertension who underwent heart catheterization and acute vasodilator testing was performed. The hemodynamic measurements during five phases (21% to 53% oxygen, 100% oxygen, 100% oxygen with 20 ppm nitric oxide, 21% to 51% oxygen, and 21% to 51% oxygen with 0.05 mg/kg to 0.29 mg/kg intravenous sildenafil of the procedures were compared.Results. Mean pulmonary arterial pressure and pulmonary vascular resistance acutely decreased with 100% oxygen with nitric oxide, and 21% to 51% oxygen with sildenafil. Mean pulmonary arterial pressure (mm Hg, mean ± standard error of the mean was 38 ± 4 during 21% to 53% oxygen, 32 ± 3 during 100% oxygen, 29 ± 2 during 100% oxygen with nitric oxide, 37 ± 3 during 21% to 51% oxygen, and 32 ± 2 during 21% to 51% oxygen with sildenafil. There was not a significant correlation between the percent change in pulmonary vascular resistance from baseline with oxygen and nitric oxide, and from baseline with sildenafil (r2 = 0.011, p = 0.738. Conclusions. Oxygen with nitric oxide and sildenafil decreased pulmonary vascular resistance. However, the pulmonary vascular effects of oxygen and nitric oxide cannot be used to predict the acute response to sildenafil. Additional studies are needed to determine whether the acute response to sildenafil can be used to predict the long-term response to treatment with an oral phosphodiesterase V inhibitor.

  11. Unusual Reactivity of the Martian Soil: Oxygen Release Upon Humidification

    Science.gov (United States)

    Yen, A. S.

    2002-01-01

    Recent lab results show that oxygen evolves from superoxide-coated mineral grains upon exposure to water vapor. This observation is additional support of the hypothesis that UV-generated O2 is responsible for the reactivity of the martian soil. Discussion of current NASA research opportunities, status of various programs within the Solar System Exploration Division, and employment opportunities within NASA Headquarters to support these programs. Additional information is contained in the original extended abstract.

  12. The effect of temperature and oxygen content on coal burnout

    Energy Technology Data Exchange (ETDEWEB)

    K. Milenkova; A.G. Borrego; D. Alvarez; J. Xiberta; R. Menendez [Instituto Nacional del Carbon, CSIC, Oviedo (Spain)

    2003-07-01

    In this study chars from six coals differing in rank and maceral composition have been prepared at 1100 and 1300{sup o}C in a drop tube reactor using four oxygen concentrations (0, 2.5, 10 and 21% oxygen). Char burnout, reactivity, morphology and optical texture have been considered in an attempt to understand the effect of temperature and oxygen concentration in relation to coal characteristics. Temperature has shown to have a different effect on conversion depending on coal rank. The high volatile coals showed similar conversions at 1100 and 1300{sup o}C at the various atmospheres tested, whereas higher rank coals showed higher conversions at 1300 than at 1100{sup o}C. The presence of oxygen in the reacting gas appears to have two opposite effects on coal combustion. On the one hand it prevents swelling and devolatilisation and on the other it enhances combustion. The burnout will depend on which process dominates. In addition, this effect appears to be temperature dependant and the inhibiting effect of oxygen on coal devolatilisation has shown to be higher at higher temperature, since at low temperature it only affects the lowest ranked coals. The presence of oxygen also affects the structure of carbonaceous material since the lower the oxygen concentration the higher the anisotropy development. The difference in temperature separating the two series of experiments (1000 and 1300{sup o}C) did not have a positive effect on the conversion of coals yielding highly porous chars whereas for coals yielding more dense structures higher conversions were achieved at higher temperatures. 7 refs., 5 figs., 1 tab.

  13. Comparison of portable oxygen concentrators in a simulated airplane environment.

    Science.gov (United States)

    Fischer, Rainald; Wanka, Eva R; Einhaeupl, Franziska; Voll, Klaus; Schiffl, Helmut; Lang, Susanne M; Gruss, Martin; Ferrari, Uta

    2013-01-01

    Portable oxygen concentrators (POC) are highly desirable for patients with lung disease traveling by airplane, as these devices allow theoretically much higher travel times if additional batteries can be used. However, it is unclear whether POCs produce enough oxygen in airplanes at cruising altitude, even if complying with aviation regulations. We evaluated five frequently used POCs (XPO2 (Invacare, USA), Freestyle (AirSep C., USA), Evergo (Philipps Healthcare, Germany), Inogen One (Inogen, USA), Eclipse 3 (Sequal, USA)) at an altitude of 2650 m (as simulated airplane environment) in 11 patients with chronic obstructive lung disease (COPD) and compared theses POCs with the standard oxygen system (WS120, EMS Ltd., Germany) used by Lufthansa. Oxygen was delivered by each POC for 30 min to each patient at rest, blood gases were then drawn from the arterialized ear lobe. All POCs were able to deliver enough oxygen to increase the PaO(2) of our subjects by at least 1.40 kPa (10 mmHg). However, to achieve this increase, the two most lightweight POCs (Freestyle and Invacare XPO2) had to be run at their maximum level. This causes a significant reduction of battery life. The three other POCs (EverGo, Inogen One, Eclipse 3) and the WS120 were able to increase the PaO(2) by more than 2.55 kPa (20 mmHg), which provides extra safety for patients with more severe basal hypoxemia. When choosing the right oxygen system for air travel in patients in COPD, not only weight, but also battery life and maximum possible oxygen output must be considered carefully. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Neuroprotection of hyperbaric oxygen therapy in sub-acute traumatic brain injury: not by immediately improving cerebral oxygen saturation and oxygen partial pressure.

    Science.gov (United States)

    Zhou, Bao-Chun; Liu, Li-Jun; Liu, Bing

    2016-09-01

    Although hyperbaric oxygen (HBO) therapy can promote the recovery of neural function in patients who have suffered traumatic brain injury (TBI), the underlying mechanism is unclear. We hypothesized that hyperbaric oxygen treatment plays a neuroprotective role in TBI by increasing regional transcranial oxygen saturation (rSO 2 ) and oxygen partial pressure (PaO 2 ). To test this idea, we compared two groups: a control group with 20 healthy people and a treatment group with 40 TBI patients. The 40 patients were given 100% oxygen of HBO for 90 minutes. Changes in rSO 2 were measured. The controls were also examined for rSO 2 and PaO 2 , but received no treatment. rSO 2 levels in the patients did not differ significantly after treatment, but levels before and after treatment were significantly lower than those in the control group. PaO 2 levels were significantly decreased after the 30-minute HBO treatment. Our findings suggest that there is a disorder of oxygen metabolism in patients with sub-acute TBI. HBO does not immediately affect cerebral oxygen metabolism, and the underlying mechanism still needs to be studied in depth.

  15. Oxygen-sensitive 3He-MRI in bronchiolitis obliterans after lung transplantation

    International Nuclear Information System (INIS)

    Gast, Klaus K.; Biedermann, Alexander; Herweling, Annette; Schreiber, Wolfgang G.; Schmiedeskamp, Joerg; Mayer, Eckhard; Heussel, Claus P.; Markstaller, Klaus; Eberle, Balthasar; Kauczor, Hans-Ulrich

    2008-01-01

    Oxygen-sensitive 3 He-MRI was studied for the detection of differences in intrapulmonary oxygen partial pressure (pO 2 ) between patients with normal lung transplants and those with bronchiolitis obliterans syndrome (BOS). Using software developed in-house, oxygen-sensitive 3 He-MRI datasets from patients with normal lung grafts (n = 8) and with BOS (n = 6) were evaluated quantitatively. Datasets were acquired on a 1.5-T system using a spoiled gradient echo pulse sequence. Underlying diseases were pulmonary emphysema (n 10 datasets) and fibrosis (n = 4). BOS status was verified by pulmonary function tests. Additionally, 3 He-MRI was assessed blindedly for ventilation defects. Median intrapulmonary pO 2 in patients with normal lung grafts was 146 mbar compared with 108 mbar in patients with BOS. Homogeneity of pO2 distribution was greater in normal grafts (standard deviation pO2 34 versus 43 mbar). Median oxygen decrease rate during breath hold was higher in unaffected patients (-1.75 mbar/s versus -0.38 mbar/s). Normal grafts showed fewer ventilation defects (5% versus 28%, medians). Oxygen-sensitive 3 He-MRI appears capable of demonstrating differences of intrapulmonary pO2 between normal lung grafts and grafts affected by BOS. Oxygen-sensitive 3 He-MRI may add helpful regional information to other diagnostic techniques for the assessment and follow-up of lung transplant recipients. (orig.)

  16. Unraveling the structure and chemical mechanisms of highly oxygenated intermediates in oxidation of organic compounds

    KAUST Repository

    Wang, Zhandong

    2017-11-28

    Decades of research on the autooxidation of organic compounds have provided fundamental and practical insights into these processes; however, the structure of many key autooxidation intermediates and the reactions leading to their formation still remain unclear. This work provides additional experimental evidence that highly oxygenated intermediates with one or more hydroperoxy groups are prevalent in the autooxidation of various oxygenated (e.g., alcohol, aldehyde, keto compounds, ether, and ester) and nonoxygenated (e.g., normal alkane, branched alkane, and cycloalkane) organic compounds. These findings improve our understanding of autooxidation reaction mechanisms that are routinely used to predict fuel ignition and oxidative stability of liquid hydrocarbons, while also providing insights relevant to the formation mechanisms of tropospheric aerosol building blocks. The direct observation of highly oxygenated intermediates for the autooxidation of alkanes at 500–600 K builds upon prior observations made in atmospheric conditions for the autooxidation of terpenes and other unsaturated hydrocarbons; it shows that highly oxygenated intermediates are stable at conditions above room temperature. These results further reveal that highly oxygenated intermediates are not only accessible by chemical activation but also by thermal activation. Theoretical calculations on H-atom migration reactions are presented to rationalize the relationship between the organic compound’s molecular structure (n-alkane, branched alkane, and cycloalkane) and its propensity to produce highly oxygenated intermediates via extensive autooxidation of hydroperoxyalkylperoxy radicals. Finally, detailed chemical kinetic simulations demonstrate the influence of these additional reaction pathways on the ignition of practical fuels.

  17. Unraveling the structure and chemical mechanisms of highly oxygenated intermediates in oxidation of organic compounds

    KAUST Repository

    Wang, Zhandong; Popolan-Vaida, Denisia M.; Chen, Bingjie; Moshammer, Kai; Mohamed, Samah; Wang, Heng; Sioud, Salim; Raji, Misjudeen; Kohse-Hö inghaus, Katharina; Hansen, Nils; Dagaut, Philippe; Leone, Stephen R.; Sarathy, Mani

    2017-01-01

    Decades of research on the autooxidation of organic compounds have provided fundamental and practical insights into these processes; however, the structure of many key autooxidation intermediates and the reactions leading to their formation still remain unclear. This work provides additional experimental evidence that highly oxygenated intermediates with one or more hydroperoxy groups are prevalent in the autooxidation of various oxygenated (e.g., alcohol, aldehyde, keto compounds, ether, and ester) and nonoxygenated (e.g., normal alkane, branched alkane, and cycloalkane) organic compounds. These findings improve our understanding of autooxidation reaction mechanisms that are routinely used to predict fuel ignition and oxidative stability of liquid hydrocarbons, while also providing insights relevant to the formation mechanisms of tropospheric aerosol building blocks. The direct observation of highly oxygenated intermediates for the autooxidation of alkanes at 500–600 K builds upon prior observations made in atmospheric conditions for the autooxidation of terpenes and other unsaturated hydrocarbons; it shows that highly oxygenated intermediates are stable at conditions above room temperature. These results further reveal that highly oxygenated intermediates are not only accessible by chemical activation but also by thermal activation. Theoretical calculations on H-atom migration reactions are presented to rationalize the relationship between the organic compound’s molecular structure (n-alkane, branched alkane, and cycloalkane) and its propensity to produce highly oxygenated intermediates via extensive autooxidation of hydroperoxyalkylperoxy radicals. Finally, detailed chemical kinetic simulations demonstrate the influence of these additional reaction pathways on the ignition of practical fuels.

  18. Highly Functionalized Cyclopentane Derivatives by Tandem Michael Addition/Radical Cyclization/Oxygenation Reactions

    Czech Academy of Sciences Publication Activity Database

    Holan, Martin; Pohl, Radek; Císařová, I.; Klepetářová, Blanka; Jones, P. G.; Jahn, Ullrich

    2015-01-01

    Roč. 21, č. 27 (2015), s. 9877-9888 ISSN 0947-6539 R&D Projects: GA ČR GA13-40188S Institutional support: RVO:61388963 Keywords : cyclization * domino reactions * electron transfer * Michael addition * radical reactions Subject RIV: CC - Organic Chemistry Impact factor: 5.771, year: 2015

  19. System Li2O-MoO3 as a catalyst of oxygen (air) electrode

    International Nuclear Information System (INIS)

    Gavdzik, A.; Gajda, S.; Sofronkov, A.

    2000-01-01

    Potential of electrode on the basis of system Li x Mo 2-x O 6 (x 0.1-0.5) in alkaline solution saturated by oxygen was studied by the method of polarization curves recording. It is ascertained that the value of stationary potential characteristic of the electrode described under the conditions mentioned is determined by reversible reaction between oxygen and water molecules, resulting in formation of hydroxyl and hydrogen peroxide anions. Practicability of using the solid solutions on the basis of molybdenum oxide with additions of lithium oxide as a catalyst of oxygen (air) electrode in electrochemical current sources is demonstrated [ru

  20. The oxygen effect in bacteriophages irradiated in different media. 1

    International Nuclear Information System (INIS)

    Korystov, Yu.N.; Veksler, F.B.

    1983-01-01

    The oxygen effect (OE) on bacteriophage T4 in a salt solution was studied. It is shown that the sign and magnitude of OE depend on the conditions of the postirradiation incubation of the phage in irradiated medium. The direct OE is due to postirradiation lesion of the phage by hydrogen peroxide which is formed in greater amounts after irradiation in oxygen than in anoxia. The addition of catalase is shown to eliminate the postirradiation inactivation of the phage. In this case an opposite OE is observed. The mechanism of this effect is a scavenge of hydrogen atoms which damage the phage by oxygen. In the presence of catalase the OE depends also on pH of the solution. It is suggested that the hydroxyl radical arising from the reaction of H 2 O 2 with Fe 2+ is responsible for the damaging effect of H 2 O 2 . (author)

  1. Oxygen transport membrane

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a novel composite oxygen transport membrane as well as its preparation and uses thereof.......The present invention relates to a novel composite oxygen transport membrane as well as its preparation and uses thereof....

  2. Zirconium oxide based ceramic solid electrolytes for oxygen detection

    International Nuclear Information System (INIS)

    Caproni, Erica

    2007-01-01

    Taking advantage of the high thermal shock resistance of zirconia-magnesia ceramics and the high oxide ion conductivity of zirconia-yttria ceramics, composites of these ceramics were prepared by mixing, pressing and sintering different relative concentrations of ZrO 2 : 8.6 mol% MgO and ZrO 2 : 3 mol% Y 2 O 3 solid electrolytes. Microstructural analysis of the composites was carried out by X-ray diffraction and scanning electron microscopy analyses. The thermal behavior was studied by dilatometric analysis. The electrical behavior was evaluated by the impedance spectroscopy technique. An experimental setup was designed for measurement the electrical signal generated as a function of the amount of oxygen at high temperatures. The main results show that these composites are partially stabilized (monoclinic, cubic and tetragonal) and the thermal behavior is similar to that of ZrO 2 : 8.6 mol% MgO materials used in disposable high temperature oxygen sensors. Moreover, the results of analysis of impedance spectroscopy show that the electrical conductivity of zirconia:magnesia is improved with zirconia-yttria addition and that the electrical signal depends on the amount of oxygen at 1000 deg C, showing that the ceramic composites can be used in oxygen sensors. (author)

  3. Seronegative necrolytic acral erythema: A distinct clinical subset?

    Directory of Open Access Journals (Sweden)

    Panda S

    2010-01-01

    Full Text Available A patient was referred to us with asymptomatic, erythematous, nonitchy, scaly lesions present bilaterally on the dorsa of his feet and toes since the last 2 months. Both the legs had pitting edema as well. There were hyperkeratosis, focal parakeratosis, acanthosis and scattered spongiosis in the epidermis, and proliferation of capillaries with perivascular infiltration of lymphomononuclear cells in the dermis. There was no serological evidence of hepatitis C virus. Laboratory investigations revealed hypoalbuminemia and low-normal serum zinc. On clinicopathological correlation, we made a diagnosis of necrolytic acral erythema (NAE. The lesions responded dramatically to oral zinc sulfate and topical clobetasol propionate within 3 weeks with disappearance of edema and scaling and only a minimal residual erythema. This is the first reported case of NAE from Eastern India. NAE with negative serology for hepatitis C may be viewed as a distinct subset of the condition that had been originally described.

  4. Human papilloma virus: a new risk factor in a subset of head and neck cancers.

    Science.gov (United States)

    Bisht, Manisha; Bist, Sampan Singh

    2011-01-01

    Head and neck cancer is the sixth most common malignancy worldwide. Tobacco smoking and alcohol consumption are two well known behavioral risk factors associated with head and neck cancer. Recently, evidence is mounting that infection with human papilloma virus, most commonly human papilloma virus-16 is responsible for a subset of head and neck squamous cell carcinoma especially tumors of tonsillar origin. The molecular pathway used by human papilloma virus to trigger malignant transformation of tissue is different from that of other well known risk factors, i.e. smoking and alcohol, associated with squamous cell carcinoma. Apparently, these subsets of patients with human papilloma virus positive tumor are more likely to have a better prognosis than human papilloma virus negative tumor. Considering this fact, the human papilloma virus infection should be determined in all oropharyngeal cancers since it can have a major impact on the decision making process of the treatment.

  5. Proteome profiling of human neutrophil granule subsets, secretory vesicles, and cell membrane

    DEFF Research Database (Denmark)

    Rørvig, Sara; Østergaard, Ole; Heegaard, Niels Henrik Helweg

    2013-01-01

    granules, SVs, and plasma membrane has been performed before. Here, we performed subcellular fractionation on freshly isolated human neutrophils by nitrogen cavitation and density centrifugation on a four-layer Percoll gradient. Granule subsets were pooled and subjected to SDS-PAGE, and gel pieces were in...... subcellular proteome profiles presented here may be used as a database in combination with the mRNA array database to predict and test the presence and localization of proteins in neutrophil granules and membranes....

  6. Integration of oxygen membranes for oxygen production in cement plants

    DEFF Research Database (Denmark)

    Puig Arnavat, Maria; Søgaard, Martin; Hjuler, Klaus

    2015-01-01

    The present paper describes the integration of oxygen membranes in cement plants both from an energy, exergy and economic point of view. Different configurations for oxygen enrichment of the tertiary air for combustion in the pre-calciner and full oxy-fuel combustion in both pre-calciner and kiln...

  7. MISSE PEACE Polymers Atomic Oxygen Erosion Results

    Science.gov (United States)

    deGroh, Kim, K.; Banks, Bruce A.; McCarthy, Catherine E.; Rucker, Rochelle N.; Roberts, Lily M.; Berger, Lauren A.

    2006-01-01

    Forty-one different polymer samples, collectively called the Polymer Erosion and Contamination Experiment (PEACE) Polymers, have been exposed to the low Earth orbit (LEO) environment on the exterior of the International Space Station (ISS) for nearly 4 years as part of Materials International Space Station Experiment 2 (MISSE 2). The objective of the PEACE Polymers experiment was to determine the atomic oxygen erosion yield of a wide variety of polymeric materials after long term exposure to the space environment. The polymers range from those commonly used for spacecraft applications, such as Teflon (DuPont) FEP, to more recently developed polymers, such as high temperature polyimide PMR (polymerization of monomer reactants). Additional polymers were included to explore erosion yield dependence upon chemical composition. The MISSE PEACE Polymers experiment was flown in MISSE Passive Experiment Carrier 2 (PEC 2), tray 1, on the exterior of the ISS Quest Airlock and was exposed to atomic oxygen along with solar and charged particle radiation. MISSE 2 was successfully retrieved during a space walk on July 30, 2005, during Discovery s STS-114 Return to Flight mission. Details on the specific polymers flown, flight sample fabrication, pre-flight and post-flight characterization techniques, and atomic oxygen fluence calculations are discussed along with a summary of the atomic oxygen erosion yield results. The MISSE 2 PEACE Polymers experiment is unique because it has the widest variety of polymers flown in LEO for a long duration and provides extremely valuable erosion yield data for spacecraft design purposes.

  8. 40 CFR 80.212 - What requirements apply to oxygenate blenders?

    Science.gov (United States)

    2010-07-01

    ... blend oxygenate into gasoline downstream of the refinery that produced the gasoline or the import facility where the gasoline was imported, are not subject to the requirements of this subpart applicable to... PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur Gasoline Sulfur Standards § 80...

  9. Relationship Between Cerebral Oxygenation and Hemodynamic and Oxygen Transport Parameters in Surgery for Acquired Heart Diseases

    Directory of Open Access Journals (Sweden)

    A. I. Lenkin

    2012-01-01

    Full Text Available Objective: to evaluate the relationship between cerebral oxygenation and hemodynamic and oxygen transport parameters in surgical correction of concomitant acquired heart diseases. Subjects and methods. Informed consent was received from 40 patients who required surgery because of concomitant (two or more acquired heart defects. During procedure, perioperative monitoring of oxygen transport and cerebral oxygenation was performed with the aid of PiCCO2 monitor (Pulsion Medical Systems, Germany and a Fore-Sight cerebral oximeter (CASMED, USA. Anesthesia was maintained with propofol and fen-tanyl, by monitoring the depth of anesthesia. Early postoperative intensive therapy was based on the protocol for early targeted correction of hemodynamic disorders. Oxygen transport and cerebral oxygenation parameters were estimated intraopera-tively and within 24 postoperative hours. A statistical analysis including evaluation of Spearman correlations was performed with the aid of SPSS 15.0. Results. During perfusion, there was a relationship between cerebral oximetry values and hemat-ocrit levels, and oxygen partial pressure in the venous blood. Furthermore, a negative correlation between cerebral oximetry values and blood lactate levels was found 30 minutes after initiation of extracorporeal circulation (EC. During the study, there was a positive correlation between cerebral oxygenation and values of cardiac index, central venous saturation, and oxygen delivery index. There was a negative relationship between cerebral oxygenation and extravascular lung water at the beginning of surgery and a correlation between cerebral oximetry values and oxygenation index by the end of the first 24 postoperative hours. Conclusion. The cerebral oxygenation values correlate -with the main determinants of oxygen transport during EC and after cardiac surgical procedures. Cerebral oximetry may be used in early targeted therapy for the surgical correction of acquired combined

  10. Determination of diffusion coefficients of oxygen atoms in ZrO2 using first-principles calculations

    International Nuclear Information System (INIS)

    Segi, Takashi; Okuda, Takanari

    2014-01-01

    Density functional theory and nudged elastic band calculations were performed in order to determine the diffusion coefficient for oxygen from monoclinic ZrO 2 . The calculated values for monoclinic ZrO 2 at 1000 K and 1500 K were 5.88 × 10 -16 cm 2 s -1 and 2.91 × 10 -11 cm 2 s -1 , respectively, and agreed with previously determined experimental values. In addition, the results of the nudged elastic band calculations suggest that interstitial oxygen sites exist between stable oxygen sites, and if oxygen atoms occupy these sites, stable structures with values for the lattice angle β of greater than 80.53° may be obtained. (author)

  11. Oxygenation measurements in head and neck cancers during hyperbaric oxygenation

    International Nuclear Information System (INIS)

    Becker, A.; Kuhnt, T.; Dunst, J.; Liedtke, H.; Krivokuca, A.; Bloching, M.

    2002-01-01

    Background: Tumor hypoxia has proven prognostic impact in head and neck cancers and is associated with poor response to radiotherapy. Hyperbaric oxygenation (HBO) offers an approach to overcome hypoxia. We have performed pO 2 measurements in selected patients with head and neck cancers under HBO to determine in how far changes in the oxygenation occur and whether a possible improvement of oxygenation parameters is maintained after HBO. Patients and Methods: Seven patients (five male, two female, age 51-63 years) with squamous cell cancers of the head and neck were investigated (six primaries, one local recurrence). The median pO 2 prior to HBO was determined with the Eppendorf histograph. Sites of measurement were enlarged cervical lymph nodes (n = 5), the primary tumor (n = 1) and local recurrence (n = 1). Patients then underwent HBO (100% O 2 at 240 kPa for 30 minutes) and the continuous changes in the oxygenation during HBO were determined with a Licox probe. Patients had HBO for 30 minutes (n = 6) to 40 minutes (n = 1). HBO was continued because the pO 2 had not reached a steady state after 30 minutes. After decompression, patients ventilated pure oxygen under normobaric conditions and the course of the pO 2 was further measured over about 15 minutes. Results: Prior to HBO, the median tumor pO 2 in the Eppendorf histography was 8.6 ± 5.4 mm Hg (range 3-19 mm Hg) and the pO 2 measured with the Licox probe was 17.3 ± 25.5 mm Hg (range 0-73 mm Hg). The pO 2 increased significantly during HBO to 550 ± 333 mm Hg (range 85-984 mm Hg, p = 0.018). All patients showed a marked increase irrespective of the oxygenation prior to HBO. The maximum pO 2 in the tumor was reached after 10-33 minutes (mean 17 minutes). After leaving the hyperbaric chamber, the pO 2 was 282 ± 196 mm Hg. All patients maintained an elevated pO 2 for further 5-25 minutes (138 ± 128 mm Hg, range 42-334 mm Hg, p = 0.028 vs the pO 2 prior to HBO). Conclusions: Hyperbaric oxygenation resulted in a

  12. Isolation of Human Skin Dendritic Cell Subsets.

    Science.gov (United States)

    Gunawan, Merry; Jardine, Laura; Haniffa, Muzlifah

    2016-01-01

    Dendritic cells (DCs) are specialized leukocytes with antigen-processing and antigen-presenting functions. DCs can be divided into distinct subsets by anatomical location, phenotype and function. In human, the two most accessible tissues to study leukocytes are peripheral blood and skin. DCs are rare in human peripheral blood (skin covering an average total surface area of 1.8 m(2) has approximately tenfold more DCs than the average 5 L of total blood volume (Wang et al., J Invest Dermatol 134:965-974, 2014). DCs migrate spontaneously from skin explants cultured ex vivo, which provide an easy method of cell isolation (Larsen et al., J Exp Med 172:1483-1493, 1990; Lenz et al., J Clin Invest 92:2587-2596, 1993; Nestle et al., J Immunol 151:6535-6545, 1993). These factors led to the extensive use of skin DCs as the "prototype" migratory DCs in human studies. In this chapter, we detail the protocols to isolate DCs and resident macrophages from human skin. We also provide a multiparameter flow cytometry gating strategy to identify human skin DCs and to distinguish them from macrophages.

  13. The Culture Repopulation Ability (CRA) Assay and Incubation in Low Oxygen to Test Antileukemic Drugs on Imatinib-Resistant CML Stem-Like Cells.

    Science.gov (United States)

    Cheloni, Giulia; Tanturli, Michele

    2016-01-01

    Chronic myeloid leukemia (CML) is a stem cell-driven disorder caused by the BCR/Abl oncoprotein, a constitutively active tyrosine kinase (TK). Chronic-phase CML patients are treated with impressive efficacy with TK inhibitors (TKi) such as imatinib mesylate (IM). However, rather than definitively curing CML, TKi induces a state of minimal residual disease, due to the persistence of leukemia stem cells (LSC) which are insensitive to this class of drugs. LSC persistence may be due to different reasons, including the suppression of BCR/Abl oncoprotein. It has been shown that this suppression follows incubation in low oxygen under appropriate culture conditions and incubation times.Here we describe the culture repopulation ability (CRA) assay, a non-clonogenic assay capable - together with incubation in low oxygen - to reveal in vitro stem cells endowed with marrow repopulation ability (MRA) in vivo. The CRA assay can be used, before moving to animal tests, as a simple and reliable method for the prescreening of drugs potentially active on CML and other leukemias with respect to their activity on the more immature leukemia cell subsets.

  14. The influences of age on T lymphocyte subsets in C57BL/6 mice

    Directory of Open Access Journals (Sweden)

    Jing Xie

    2017-01-01

    Full Text Available The aim of this study is to evaluate the age related changes of T lymphocyte subsets in C57BL/6 mice and immune function. Multi-color immunofluorescence techniques that were used to analyse relative numbers of T lymphocyte subsets include CD4+, CD8+, naive and memory CD4+ and CD8+, CD8+CD28+ T cells in peripheral blood of C57BL/6 mice from different age groups (Group I: 2 months old; Group II: 7 months old; Group III: 21 months old; Splenocytes isolated from different group mice were stimulated with Con A to evaluate the proliferative ability. Compared with group I, group II had a significant reduction in the percentage of CD4+, naive CD4+ and CD8+ T cells and an increase in the percentage of CD8+ T cells, while group III had a significant reduction in the percentage of CD4+, naive CD4+ and CD8+ T cells and increase in the percentage of CD8+, memory CD4+ and CD8+ T cells in peripheral blood. Compared with group II, group III had a significant reduction in the percentage of naive CD8+ T cells and increase in the percentage of memory CD4+ and CD8+, CD8+CD28+ T cells in peripheral blood. The T lymphocyte proliferation in vitro showed that groups II and III had a lower proliferative capacity than group I, between groups II and III, there was not a significant difference. We provide relative values for the T lymphocyte subsets in the different age groups of C57BL/6 mice. The immune system began aging at 7 months old in C57BL/6 mice under a specific pathogen free environment.

  15. Distribution of cyclophilin B-binding sites in the subsets of human peripheral blood lymphocytes.

    Science.gov (United States)

    Denys, A; Allain, F; Foxwell, B; Spik, G

    1997-08-01

    Cyclophilin B (CyPB) is a cyclosporin A (CsA)-binding protein, mainly associated with the secretory pathway and released in biological fluids. We have recently demonstrated that both free CyPB and CyPB-CsA complex specifically bind to peripheral blood T lymphocytes and are internalized. These results suggest that CyPB might promote the targeting of the drug into sensitive cells. Peripheral blood lymphocytes are subdivided in several populations according to their biological functions and sensitivity to CsA. We have investigated the binding of CyPB to these different subsets using a CyPB derivatized by fluorescein through its single cysteine which retains its binding properties. We have confirmed that only T cells were involved in the interaction with CyPB. The ligand binding was found to be heterogeneously distributed on the different T-cell subsets and surface-bound CyPB was mainly associated with the CD4-positive cells. No significant difference was noted between the CD45RA and CD45RO subsets, demonstrating that CyPB-binding sites were equally distributed between native and memory T cells. CD3 stimulation of T lymphocytes led to a decrease in the CyPB-binding capacity, that may be explained by a down-regulation of the CyPB-receptor expression upon T-cell activation. Finally, we demonstrated that CyPB-receptor-positive cells, isolated on CyPB sulphydryl-coupled affinity matrices, are more sensitive to CyPB-complexed CsA than mixed peripheral blood lymphocytes, suggesting that CyPB potentiates CsA activity through the binding of the complex. Taken together, our results demonstrate that CyPB-binding sites are mainly associated with resting cells of the helper T lymphocyte, and that CyPB might modulate the distribution of CsA through the drug targeting to sensitive cells.

  16. Distinct patterns of novel gene mutations in poor-prognostic stereotyped subsets of chronic lymphocytic leukemia

    DEFF Research Database (Denmark)

    Strefford, J C; Sutton, L-A; Baliakas, P

    2013-01-01

    Recent studies have revealed recurrent mutations of the NOTCH1, SF3B1 and BIRC3 genes in chronic lymphocytic leukemia (CLL), especially among aggressive, chemorefractory cases. Nevertheless, it is currently unknown whether their presence may differ in subsets of patients carrying stereotyped B...

  17. VARIATIONS IN RADIATION SENSITIVITY AND REPAIR AMONG DIFFERENT HEMATOPOIETIC STEM-CELL SUBSETS FOLLOWING FRACTIONATED-IRRADIATION

    NARCIS (Netherlands)

    DOWN, JD; BOUDEWIJN, A; VANOS, R; THAMES, HD; PLOEMACHER, RE

    1995-01-01

    The radiation dose-survival of various hematopoietic cell subsets in murine bone marrow (BM) was determined in the cobblestone area forming cell (CAFC) assay under conditions of single-, split-, and multiple-dose irradiation. A greater recovery in cell survival with decreasing dose per fraction, or

  18. Kinetics of oxygen species in an electrically driven singlet oxygen generator

    Energy Technology Data Exchange (ETDEWEB)

    Azyazov, V.N., E-mail: azyazov@fian.smr.ru [Samara State Aerospace University, 443086 (Russian Federation); Lebedev Physical Institute of RAS, Samara 443011 (Russian Federation); Torbin, A.P.; Pershin, A.A. [Samara State Aerospace University, 443086 (Russian Federation); Lebedev Physical Institute of RAS, Samara 443011 (Russian Federation); Mikheyev, P.A., E-mail: mikheyev@fian.smr.ru [Samara State Aerospace University, 443086 (Russian Federation); Lebedev Physical Institute of RAS, Samara 443011 (Russian Federation); Heaven, M.C., E-mail: mheaven@emory.edu [Emory University, Atlanta, GA 30322 (United States)

    2015-12-16

    Highlights: • Vibrational excitation of O{sub 3} increases the rate constant for O{sub 3} + O{sub 2}(a) → 2O{sub 2}(X) + O. • Vibrationally excited O{sub 3} is produced by the O + O{sub 2}(X) + M → O{sub 3} + M reaction. • Ozone concentrations are impacted by the reactions of vibrationally excited O{sub 3}. • Relevant to ozone concentrations in oxygen discharges and the upper atmosphere. - Abstract: The kinetics of oxygen species in the gaseous medium of a discharge singlet oxygen generator has been revisited. Vibrationally excited ozone O{sub 3}(υ) formed in O + O{sub 2} recombination is thought to be a significant agent in the deactivation of singlet oxygen O{sub 2}(a{sup 1}Δ), oxygen atom removal and ozone formation. It is shown that the process O{sub 3}(υ ⩾ 2) + O{sub 2}(a{sup 1}Δ) → 2O{sub 2} + O is the main O{sub 2}(a{sup 1}Δ) deactivation channel in the post-discharge zone. If no measures are taken to decrease the oxygen atom concentration, the contribution of this process to the overall O{sub 2}(a{sup 1}Δ) removal is significant, even in the discharge zone. A simplified model for the kinetics of vibrationally excited ozone is proposed. Calculations based on this model yield results that are in good agreement with the experimental data.

  19. A theoretical model for the effects of reduced hemoglobin-oxygen affinity on tumor oxygenation

    International Nuclear Information System (INIS)

    Kavanagh, Brian D.; Secomb, Timothy W.; Hsu, Richard; Lin, P.-S.; Venitz, Jurgen; Dewhirst, Mark W.

    2002-01-01

    Purpose: To develop a theoretical model for oxygen delivery to tumors, and to use the model to simulate the effects of changing the affinity of hemoglobin for oxygen on tumor oxygenation. Methods and Materials: Hemoglobin affinity is expressed in terms of P 50 , the partial pressure of oxygen (Po 2 ) at half saturation. Effects of changing P 50 on arterial Po 2 are predicted using an effective vessel approach to describe diffusive oxygen transport in the lungs, assuming fixed systemic oxygen demand and fixed blood flow rate. The decline in oxygen content of blood as it flows through normal tissue before entering the tumor region is assumed fixed. The hypoxic fraction of the tumor region is predicted using a three-dimensional simulation of diffusion from a network of vessels whose geometry is derived from observations of tumor microvasculature in the rat. Results: In air-breathing rats, predicted hypoxic fraction decreases with moderate increases in P 50 , but increases with further increases of P 50 , in agreement with previous experimental results. In rats breathing hyperoxic gases, and in humans breathing either normoxic or hyperoxic gases, increased P 50 is predicted to improve tumor oxygenation. Conclusions: The results support the administration of synthetic agents to increase P 50 during radiation treatment of tumors

  20. A laser-based sensor for measurement of off-gas composition and temperature in basic oxygen steelmaking

    International Nuclear Information System (INIS)

    Ottesen, D.; Allendorf, S.; Ludowise, P.; Hardesty, D.; Miller, T.; Goldstein, D.; Smith, C.; Bonin, M.

    1999-01-01

    We are developing an optical sensor for process control in basic oxygen steelmaking. The sensor measures gas temperature and relative CO/CO 2 concentration ratios in the furnace off-gas by transmitting the laser probe beam directly above the furnace lip and below the exhaust hood during oxygen blowing. Dynamic off-gas information is being evaluated for optimizing variables such as lance height, oxygen flow, post-combustion control, and prediction of final melt-carbon content. The non-invasive nature of the optical sensor renders it robust and relatively maintenance-free. Additional potential applications of the method are process control for electric arc furnace and bottom-blown oxygen steelmaking processes. (author)