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Sample records for oxygen utilization rate

  1. The Rate of Oxygen Utilization by Cells

    PubMed Central

    Wagner, Brett A.; Venkataraman, Sujatha; Buettner, Garry R.

    2011-01-01

    The discovery of oxygen is considered by some to be the most important scientific discovery of all time – from both physical-chemical/astrophysics and biology/evolution viewpoints. One of the major developments during evolution is the ability to capture dioxygen in the environment and deliver it to each cell in the multicellular, complex mammalian body -- on demand, i.e. just-in-time. Humans use oxygen to extract approximately 2550 Calories (10.4 MJ) from food to meet daily energy requirements. This combustion requires about 22 moles of dioxygen per day, or 2.5 × 10-4 mol s-1. This is an average rate of oxygen utilization of 2.5 × 10-18 mol cell-1 s-1, i.e. 2.5 amol cell-1 s-1. Cells have a wide range of oxygen utilization, depending on cell type, function, and biological status. Measured rates of oxygen utilization by mammalian cells in culture range from <1 to >350 amol cell-1 s-1. There is a loose positive linear correlation of the rate of oxygen consumption (OCR) by mammalian cells in culture with cell volume and cell protein. The use of oxygen by cells and tissues is an essential aspect of the basic redox biology of cells and tissues. This type of quantitative information is fundamental to investigations in quantitative redox biology, especially redox systems biology. PMID:21664270

  2. The Relationships between Arterial Oxygen Flow Rate, Oxygen Binding by Hemoglobin, and Oxygen Utilization after Myocardial Infarction

    PubMed Central

    Lichtman, Marshall A.; Cohen, Jules; Young, Jerald A.; Whitbeck, April A.; Murphy, Marion

    1974-01-01

    The interrelationships of arterial oxygen flow rate index, oxygen binding by hemoglobin, and oxygen consumption have been examined in patients with acute myocardial infarction. Proportional extraction of oxygen increased in close association with decreasing oxygen flow rate, and hence, whole body oxygen consumption was constant over nearly a three-fold variation in arterial oxygen flow rate. A reduction in hemoglobin-oxygen affinity at in vivo conditions of pH. Pco2 and temperature also occurred in proportion to the reduction in arterial oxygen flow rate. Therefore, the increased proportional removal of oxygen from arterial blood at low oxygen flow rates, required to maintain oxygen consumption, may have been facilitated by the reduced affinity of hemoglobin for oxygen at in vivo conditions. However, the decrease in affinity did not appear to explain more than 30-40% of the increased extraction. Respiratory alkalosis was a frequent occurrence in these patients and 2,3-diphosphoglycerate was positively associated with blood pH as well as with the time-averaged proportion of deoxyhemoglobin in arterial and venous blood. Hemoglobin-oxygen affinity measured at standard conditions and the mixed venous oxygen saturation were equally good indicators of reduced arterial oxygen flow rate in patients without shock. However, S̄vo2 is more easily measured and is a more useful indicator of reduced oxygen flow rate, since its relationship to oxygen flow appears to be independent of affinity changes and time. PMID:4855047

  3. a Dynamic Technique for the Quantitation of Oxygen Utilization Rates Using Positron Emission Tomography

    NASA Astrophysics Data System (ADS)

    Hutchins, Gary Dwight

    The conversion of oxygen to water in oxidative phosphorylation is required for the efficient production of adenosine triphosphate. This process can be monitored externally using oxygen-15 and positron emission tomography to allow estimation of metabolic rate in the human brain. A dynamic technique using ('15)O-O(,2) has been developed and compared to the existing steady state and autoradiographic approaches. These currently employed methods suffer from pitfalls associated with using assumed values for the tissue -blood partition coefficient of water. Computer simulations have been performed demonstrating the underestimation of physiological rates with the steady state technique and the time varying solutions of the autoradiographic approach. Experimental data agrees with the predicted behavior of each of these methods. The new technique requires the estimation of local cerebral blood volume and the tissue-blood partition coefficient value of water. The blood volume, necessary for a blood radioactivity correction, is estimated from the equilibrium distribution of ('15)O-CO. The tissue-blood partition coefficient is calculated using a rapid least squares analysis of ('15)O-H(,2)O dynamic blood flow data. The measured values of blood volume and partition coefficient are assumed to remain invariant with changes in the physiological state of the brain. The metabolic rate is then estimated by fitting the oxygen model to the observed kinetics in a one minute breathhold study. Alternatives to arterial blood sampling have been considered. Expired breath and lung activity concentrations used in conjunction with arterial blood sample data provide the required input functions. A time-of-flight probe has been developed as a non-invasive alternative and some intial measurements with the system are presented. The experimental data are in good agreement with the model predictions supporting the switch to a dynamic technique for the estimation of oxygen utilization rate using ('15

  4. Oxygen consumption rate v. rate of energy utilization of fishes: a comparison and brief history of the two measurements.

    PubMed

    Nelson, J A

    2016-01-01

    Accounting for energy use by fishes has been taking place for over 200 years. The original, and continuing gold standard for measuring energy use in terrestrial animals, is to account for the waste heat produced by all reactions of metabolism, a process referred to as direct calorimetry. Direct calorimetry is not easy or convenient in terrestrial animals and is extremely difficult in aquatic animals. Thus, the original and most subsequent measurements of metabolic activity in fishes have been measured via indirect calorimetry. Indirect calorimetry takes advantage of the fact that oxygen is consumed and carbon dioxide is produced during the catabolic conversion of foodstuffs or energy reserves to useful ATP energy. As measuring [CO2 ] in water is more challenging than measuring [O2 ], most indirect calorimetric studies on fishes have used the rate of O2 consumption. To relate measurements of O2 consumption back to actual energy usage requires knowledge of the substrate being oxidized. Many contemporary studies of O2 consumption by fishes do not attempt to relate this measurement back to actual energy usage. Thus, the rate of oxygen consumption (M˙O2 ) has become a measurement in its own right that is not necessarily synonymous with metabolic rate. Because all extant fishes are obligate aerobes (many fishes engage in substantial net anaerobiosis, but all require oxygen to complete their life cycle), this discrepancy does not appear to be of great concern to the fish biology community, and reports of fish oxygen consumption, without being related to energy, have proliferated. Unfortunately, under some circumstances, these measures can be quite different from one another. A review of the methodological history of the two measurements and a look towards the future are included. PMID:26768970

  5. Transit time distributions and oxygen utilization rates from chlorofluorocarbons and sulfur hexafluoride in the Southeast Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Sonnerup, Rolf E.; Mecking, Sabine; Bullister, John L.; Warner, Mark J.

    2015-05-01

    Chlorofluorocarbons-11 (CFC-11), CFC-12, and sulfur hexafluoride (SF6) were measured during the December 2007 to February 2008 CLIVAR/Repeat Hydrography (RH) P18 section along ˜103°W in the Southeast Pacific Ocean. Transit-time distributions (TTDs) of 1-D transport that matched all three tracers were consistent with high Peclet number flow ventilating the subtropical mode water and the main subtropical thermocline (30°S-42°S, 200-800 m). In the subtropics, TTDs with predominantly advective transport predicted decadal increases in CFC-12 and CFC-11 consistent with those observed comparing 1994 WOCE with 2007/2008 CLIVAR/RH data, indicating steady ventilation in this region, and consistent with the near-zero changes observed in dissolved oxygen. The mean transport timescales from the tracer-tuned TTDs were used to estimate apparent oxygen utilization rates (OURs) on the order of 8-20 μmol kg-1 yr-1 at ˜200 m depth, attenuating to ˜2 μmol kg-1 yr-1 typically by 500 m depth in this region. Depth-integrated over the thermocline, these OURs implied carbon export rates from the overlying sea surface on the order of ˜1.8 moles C m-2 yr-1 from 30°S to 45°S, 2-2.5 moles C m-2 yr-1 from 45°S to 52°S, and 2.5-3.5 moles C m-2 yr-1 from 52°S to 60°S.

  6. Controlling Your Utility Rates.

    ERIC Educational Resources Information Center

    Lucht, Ray; Dembowski, Frederick L.

    1985-01-01

    A cost-effective alternative to high utility bills for middle-sized and smaller utility users is the service of utility rate consultants. The consultants analyze utility invoices for the previous 12 months to locate available refunds or credits. (MLF)

  7. Transit time distributions and oxygen utilization rates in the Northeast Pacific Ocean from chlorofluorocarbons and sulfur hexafluoride

    NASA Astrophysics Data System (ADS)

    Sonnerup, Rolf E.; Mecking, Sabine; Bullister, John L.

    2013-02-01

    Depth profiles of dissolved chlorofluorocarbon-11 (CFC-11) and sulfur hexafluoride (SF6) were measured during a September 2008 cruise in the Northeast Pacific Ocean. For each water sample, the two tracers were used in concert to estimate likely mean ages and widths of parameterized 1-D transit time distributions (TTDs). In shallow waters (<250 m), the TTDs' mean ages were relatively loosely constrained due to the slow decrease of atmospheric CFC-11 since 1994. In the main thermocline (25.0-26.6 σθ, ∼300-550 m), the CFC-11/SF6 tracer pair constrained TTDs' mean ages to within±10%. Deeper than 26.8 σθ (∼600 m), SF6 levels in 2008 were too low for the CFC-11/SF6 tracer pair to constrain the TTDs' mean ages. Within the main thermocline of the subtropical North Pacific Ocean (20°-37°N along 152°W), the TTDs' mean ages were used to estimate Oxygen Utilization Rates (OURs) of ∼11 μmol kg-1 yr-1 on 25.0-25.5 σθ (∼160 m), attenuating to very low rates (0.12 μmol kg-1 yr-1) by 26.8-27.0 σθ (∼600 m). Depth integration of the in-situ OURs implied an average carbon remineralization rate of 1.7±0.3 mol C m-2 yr-1 in this region and depth range, somewhat lower than other independent estimates. Along the 152°W section, depth integrating the apparent OURs implied carbon remineralization rates of 2.5-3.5 mol C m-2 yr-1 from 20°N to 30°N, 3.5-4.0 mol C m-2 yr-1 from 30°N to 40°N, and 2-2.7 mol C m-2 yr-1 north of 45°N.

  8. National Utility Rate Database: Preprint

    SciTech Connect

    Ong, S.; McKeel, R.

    2012-08-01

    When modeling solar energy technologies and other distributed energy systems, using high-quality expansive electricity rates is essential. The National Renewable Energy Laboratory (NREL) developed a utility rate platform for entering, storing, updating, and accessing a large collection of utility rates from around the United States. This utility rate platform lives on the Open Energy Information (OpenEI) website, OpenEI.org, allowing the data to be programmatically accessed from a web browser, using an application programming interface (API). The semantic-based utility rate platform currently has record of 1,885 utility rates and covers over 85% of the electricity consumption in the United States.

  9. Energy utilization rates during shuttle extravehicular activities.

    PubMed

    Waligora, J M; Kumar, K V

    1995-01-01

    The work rates or energy utilization rates during EVA are major factors in sizing of life support systems. These rates also provide a measure of ease of EVA and its cost in crew fatigue. From the first Shuttle EVA on the STS-6 mission in 1983, we have conducted 59 man-EVA and 341 man-hours of EVA. Energy utilization rates have been measured on each of these EVA. Metabolic rate was measured during each EVA using oxygen utilization corrected for suit leakage. From 1981-1987, these data were available for average data over the EVA or over large segments of the EVA. Since 1987, EVA oxygen utilization data were available at 2-minute intervals. The average metabolic rate on Shuttle EVA (194 kcal/hr.) has been significantly lower than metabolic rates during Apollo and Skylab missions. Peak rates have been below design levels, infrequent, and of short duration. The data suggest that the energy cost of tasks may be inversely related to the degree of training for the task. The data provide insight on the safety margins provided by life support designs and on the energy cost of Station construction EVA. PMID:11540993

  10. Aquatic Respiration Rate Measurements at Low Oxygen Concentrations

    PubMed Central

    Holtappels, Moritz; Tiano, Laura; Kalvelage, Tim; Lavik, Gaute; Revsbech, Niels Peter; Kuypers, Marcel M. M.

    2014-01-01

    Despite its huge ecological importance, microbial oxygen respiration in pelagic waters is little studied, primarily due to methodological difficulties. Respiration measurements are challenging because of the required high resolution of oxygen concentration measurements. Recent improvements in oxygen sensing techniques bear great potential to overcome these limitations. Here we compare 3 different methods to measure oxygen consumption rates at low oxygen concentrations, utilizing amperometric Clark type sensors (STOX), optical sensors (optodes), and mass spectrometry in combination with 18-18O2 labeling. Oxygen concentrations and consumption rates agreed well between the different methods when applied in the same experimental setting. Oxygen consumption rates between 30 and 400 nmol L−1 h−1 were measured with high precision and relative standard errors of less than 3%. Rate detection limits in the range of 1 nmol L−1 h−1 were suitable for rate determinations in open ocean water and were lowest at the lowest applied O2 concentration. PMID:24586724

  11. OXYGEN UTILIZATION IN ACTIVATED SLUDGE PLANTS: SIMULATION AND MODEL CALIBRATION

    EPA Science Inventory

    The objective of the research described in the report is to apply recent advances in activated sludge process modeling to the simulation of oxygen utilization rates in full scale activated sludge treatment plants. This is accomplished by calibrating the International Association ...

  12. Early oxygen-utilization and brain activity in preterm infants.

    PubMed

    Tataranno, Maria Luisa; Alderliesten, Thomas; de Vries, Linda S; Groenendaal, Floris; Toet, Mona C; Lemmers, Petra M A; Vosse van de, Renè E; van Bel, Frank; Benders, Manon J N L

    2015-01-01

    The combined monitoring of oxygen supply and delivery using Near-InfraRed spectroscopy (NIRS) and cerebral activity using amplitude-integrated EEG (aEEG) could yield new insights into brain metabolism and detect potentially vulnerable conditions soon after birth. The relationship between NIRS and quantitative aEEG/EEG parameters has not yet been investigated. Our aim was to study the association between oxygen utilization during the first 6 h after birth and simultaneously continuously monitored brain activity measured by aEEG/EEG. Forty-four hemodynamically stable babies with a GA < 28 weeks, with good quality NIRS and aEEG/EEG data available and who did not receive morphine were included in the study. aEEG and NIRS monitoring started at NICU admission. The relation between regional cerebral oxygen saturation (rScO2) and cerebral fractional tissue oxygen extraction (cFTOE), and quantitative measurements of brain activity such as number of spontaneous activity transients (SAT) per minute (SAT rate), the interval in seconds (i.e. time) between SATs (ISI) and the minimum amplitude of the EEG in μV (min aEEG) were evaluated. rScO2 was negatively associated with SAT rate (β=-3.45 [CI=-5.76- -1.15], p=0.004) and positively associated with ISI (β=1.45 [CI=0.44-2.45], p=0.006). cFTOE was positively associated with SAT rate (β=0.034 [CI=0.009-0.059], p=0.008) and negatively associated with ISI (β=-0.015 [CI=-0.026- -0.004], p=0.007). Oxygen delivery and utilization, as indicated by rScO2 and cFTOE, are directly related to functional brain activity, expressed by SAT rate and ISI during the first hours after birth, showing an increase in oxygen extraction in preterm infants with increased early electro-cerebral activity. NIRS monitored oxygenation may be a useful biomarker of brain vulnerability in high-risk infants. PMID:25965343

  13. Reduced oxygen utilization in septic shock: disorder or adaptation?

    PubMed Central

    Steiner, Alexandre A

    2015-01-01

    A fall in oxygen utilization during septic or endotoxic shock is thought to reflect circulatory hypoxia or mitochondrial dysfunction, but these pathology-oriented hypotheses do not explain all clinical observations. Here we discuss an alternative hypothesis of how oxygen utilization could fall as the result of a physiological thermometabolic adaptation. PMID:27227060

  14. Cardiogenic Shock: Failure of Oxygen Delivery and Oxygen Utilization.

    PubMed

    Lim, Hoong Sern

    2016-08-01

    Cardiogenic shock remains a highly lethal condition. Conventional therapy including revascularization and mechanical circulatory support aims to improve cardiac output and oxygen delivery, but increasing basic and clinical observations indicate wider circulatory and cellular abnormalities, particularly at the advanced stages of shock. Progressive cardiogenic shock is associated with microcirculatory and cellular abnormalities. Cardiogenic shock is initially characterized by a failure to maintain global oxygen delivery; however, progressive cardiogenic shock is associated with the release of pro-inflammatory cytokines, derangement of the regulation of regional blood flow, microcirculatory abnormalities, and cellular dysoxia. These abnormalities are analogous to septic shock and may not be reversed by increase in oxygen delivery, even to supranormal levels. Earlier mechanical circulatory support in cardiogenic shock may limit the development of microcirculatory and cellular abnormalities. PMID:27509355

  15. Ammonia producing engine utilizing oxygen separation

    DOEpatents

    Easley, Jr., William Lanier; Coleman, Gerald Nelson; Robel, Wade James

    2008-12-16

    A power system is provided having a power source, a first power source section with a first intake passage and a first exhaust passage, a second power source section with a second intake passage and a second exhaust passage, and an oxygen separator. The second intake passage may be fluidly isolated from the first intake passage.

  16. Linking Pulmonary Oxygen Uptake, Muscle Oxygen Utilization and Cellular Metabolism during Exercise

    PubMed Central

    Lai, Nicola; Camesasca, Marco; Saidel, Gerald M.; Dash, Ranjan K.; Cabrera, Marco E.

    2014-01-01

    The energy demand imposed by physical exercise on the components of the oxygen transport and utilization system requires a close link between cellular and external respiration in order to maintain ATP homeostasis. Invasive and non-invasive experimental approaches have been used to elucidate mechanisms regulating the balance between oxygen supply and consumption during exercise. Such approaches suggest that the mechanism controlling the various subsystems coupling internal to external respiration are part of a highly redundant and hierarchical multi-scale system. In this work, we present a “systems biology” framework that integrates experimental and theoretical approaches able to provide simultaneously reliable information on the oxygen transport and utilization processes occurring at the various steps in the pathway of oxygen from air to mitochondria, particularly at the onset of exercise. This multi-disciplinary framework provides insights into the relationship between cellular oxygen consumption derived from measurements of muscle oxygenation during exercise and pulmonary oxygen uptake by indirect calorimetry. With a validated model, muscle oxygen dynamic responses is simulated and quantitatively related to cellular metabolism under a variety of conditions. PMID:17380394

  17. Evaluation of oxygen utilization as an indicator of municipal solid-waste compost stability

    SciTech Connect

    Zimmerman, R.A.

    1991-01-01

    This research evaluated oxygen utilization parameters as indicators of MSW compost stability. Parameters evaluated were the oxygen utilization rate (OUR), specific oxygen uptake rate (SOUR), five-day biochemical oxygen demand, and chemical oxygen demand. In addition, other suggested indicators of stability were investigated including percent volatile solids, volatile solids reduction, nitrogen content, carbon: nitrogen ratio, and reheating potential (RP). OUR is a measure of the rate of oxygen utilization by the microorganisms in the decomposition of organic matter in compost. OUR was observed to be sensitive to the degree of stabilization and decreased with increasing compost age and stability. OUR values near zero indicate that the compost microorganisms are in a state of endogenous respiration, which is characteristic of a stable compost. Therefore, OUR is an excellent indicator of stability. A number of disadvantages are associated with OUR for practical application. Therefore, other parameters were evaluated as indicators of stability based on their statistical correlation to OUR. RP exhibited the strongest correlation to OUR. In combination, RP and SOUR were the two parameters which exhibited the strongest correlation to OUR. OUR, RP, and SOUR are all measures of microbial activity which reflect the degree of organic decomposition, and therefore, stability. Based on the results of this research; OUR, RP, and SOUR are useful parameters in assessing compost stability.

  18. Arterio-venous shunts or low oxygen utilization?

    PubMed

    Rozin, Alexander P

    2010-02-01

    An idea of arteriovenous shunts (AVS) was proposed for explanation of dynamic regulation of oxygenation and venous hyperoxia. A formula enabling calculation of AVS and real CO2 production has recently been derived by comparing data of arterial and venous blood gases. Regarding venous hyperoxia, there is a need to differentiate capillary to tissue transport defect (low oxygen utilisation-LOU) from AVS, which may exist simultaneously. The AVS may be associated with normal or relatively high oxygen utilization from the capillary vessels and increased CO2 production. AVS is proposed to carry protective and 'stealing' properties including renal, cardiac, and pulmonary hemodynamic. Calculations of the AVS may be important for dynamic assessment of vascular and metabolic status and in emergency medicine. PMID:20026514

  19. Inner retinal metabolic rate of oxygen by oxygen tension and blood flow imaging in rat

    PubMed Central

    Wanek, Justin; Teng, Pang-yu; Albers, John; Blair, Norman P.; Shahidi, Mahnaz

    2011-01-01

    Abstract The metabolic function of inner retinal cells relies on the availability of nutrients and oxygen that are supplied by the retinal circulation. Assessment of retinal tissue vitality and function requires knowledge of both the rate of oxygen delivery and consumption. The purpose of the current study is to report a novel technique for assessment of the inner retinal metabolic rate of oxygen (MO2) by combined measurements of retinal blood flow and vascular oxygen tension (PO2) in rat. The application of this technology has the potential to broaden knowledge of retinal oxygen dynamics and advance understanding of disease pathophysiology. PMID:21991548

  20. Utilization of oxygen-enriched air in diesel engines: Fundamental considerations

    SciTech Connect

    Lahiri, D.; Mehta, P.S.; Poola, R.B.; Sekar, R.

    1997-09-01

    Utilization of oxygen-enriched air in diesel engines holds potential for low exhaust smoke and particulate emissions. The majority of the oxygen-enriched-air combustion-related studies so far are experimental in nature, where the observed results are understood on an overall basis. This paper deals with the fundamental considerations associated with the oxygen-enriched air-fuel combustion process to enhance understanding of the concept. The increase in adiabatic flame temperature, the composition of exhaust gases at equilibrium, and also the changes in thermodynamic and transport properties due to oxygen-enrichment of standard intake air are computed. The effects of oxygen-enrichment on fuel evaporation rate, ignition delay, and premixed burnt fraction are also evaluated. Appropriate changes in the ignition delay correlation to reflect the effects of oxygen-enrichment are proposed. The notion of oxygen-enrichment of standard intake air as being akin to leaning of the fuel-air mixture is refuted on the basis of the fundamentally different requirements for the oxygen-enriched combustion process.

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

    PubMed

    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. PMID:19246069

  2. Fuel Cells Utilizing Oxygen From Air at Low Pressures

    NASA Technical Reports Server (NTRS)

    Cisar, Alan; Boyer, Chris; Greenwald, Charles

    2006-01-01

    A fuel cell stack has been developed to supply power for a high-altitude aircraft with a minimum of air handling. The fuel cell is capable of utilizing oxygen from ambient air at low pressure with no need for compression. For such an application, it is advantageous to take oxygen from the air (in contradistinction to carrying a supply of oxygen onboard), but it is a challenging problem to design a fuel-cell stack of reasonable weight that can generate sufficient power while operating at reduced pressures. The present fuel-cell design is a response to this challenge. The design features a novel bipolar plate structure in combination with a gas-diffusion structure based on a conductive metal core and a carbon gas-diffusion matrix. This combination makes it possible for the flow fields in the stack to have a large open fraction (ratio between open volume and total volume) to permit large volumes of air to flow through with exceptionally low backpressure. Operations at reduced pressure require a corresponding increase in the volume of air that must be handled to deliver the same number of moles of oxygen to the anodes. Moreover, the increase in the open fraction, relative to that of a comparable prior fuel-cell design, reduces the mass of the stack. The fuel cell has been demonstrated to operate at a power density as high as 105 W/cm2 at an air pressure as low as 2 psia (absolute pressure 14 kPa), which is the atmospheric pressure at an altitude of about 50,000 ft ( 15.2 km). The improvements in the design of this fuel cell could be incorporated into designs of other fuel cells to make them lighter in weight and effective at altitudes higher than those of prior designs. Potential commercial applications for these improvements include most applications now under consideration for fuel cells.

  3. Quantifying consumption rates of dissolved oxygen along bed forms

    NASA Astrophysics Data System (ADS)

    Boano, Fulvio; De Falco, Natalie; Arnon, Shai

    2016-04-01

    Streambed interfaces represent hotspots for nutrient transformations because they host different microbial species, and the evaluation of these reaction rates is important to assess the fate of nutrients in riverine environments. In this work we analyze a series of flume experiments on oxygen demand in dune-shaped hyporheic sediments under losing and gaining flow conditions. We employ a new modeling code to quantify oxygen consumption rates from observed vertical profiles of oxygen concentration. The code accounts for transport by molecular diffusion and water advection, and automatically determines the reaction rates that provide the best fit between observed and modeled concentration values. The results show that reaction rates are not uniformly distributed across the streambed, in agreement with the expected behavior predicted by hyporheic exchange theory. Oxygen consumption was found to be highly influenced by the presence of gaining or losing flow conditions, which controlled the delivery of labile DOC to streambed microorganisms.

  4. Sexual Preferences in Nutrient Utilization Regulate Oxygen Consumption and Reactive Oxygen Species Generation in Schistosoma mansoni: Potential Implications for Parasite Redox Biology

    PubMed Central

    Oliveira, Matheus P.; Correa Soares, Juliana B. R.; Oliveira, Marcus F.

    2016-01-01

    Schistosoma mansoni, one of the causative agents of human schistosomiasis, has a unique antioxidant network that is key to parasite survival and a valuable chemotherapeutic target. The ability to detoxify and tolerate reactive oxygen species increases along S. mansoni development in the vertebrate host, suggesting that adult parasites are more exposed to redox challenges than young stages. Indeed, adult parasites are exposed to multiple redox insults generated from blood digestion, activated immune cells, and, potentially, from their own parasitic aerobic metabolism. However, it remains unknown how reactive oxygen species are produced by S. mansoni metabolism, as well as their biological effects on adult worms. Here, we assessed the contribution of nutrients and parasite gender to oxygen utilization pathways, and reactive oxygen species generation in whole unpaired adult S. mansoni worms. We also determined the susceptibilities of both parasite sexes to a pro-oxidant challenge. We observed that glutamine and serum importantly contribute to both respiratory and non-respiratory oxygen utilization in adult worms, but with different proportions among parasite sexes. Analyses of oxygen utilization pathways revealed that respiratory rates were high in male worms, which contrast with high non-respiratory rates in females, regardless nutritional sources. Interestingly, mitochondrial complex I-III activity was higher than complex IV specifically in females. We also observed sexual preferences in substrate utilization to sustain hydrogen peroxide production towards glucose in females, and glutamine in male worms. Despite strikingly high oxidant levels and hydrogen peroxide production rates, female worms were more resistant to a pro-oxidant challenge than male parasites. The data presented here indicate that sexual preferences in nutrient metabolism in adult S. mansoni worms regulate oxygen utilization and reactive oxygen species production, which may differently contribute

  5. Sexual Preferences in Nutrient Utilization Regulate Oxygen Consumption and Reactive Oxygen Species Generation in Schistosoma mansoni: Potential Implications for Parasite Redox Biology.

    PubMed

    Oliveira, Matheus P; Correa Soares, Juliana B R; Oliveira, Marcus F

    2016-01-01

    Schistosoma mansoni, one of the causative agents of human schistosomiasis, has a unique antioxidant network that is key to parasite survival and a valuable chemotherapeutic target. The ability to detoxify and tolerate reactive oxygen species increases along S. mansoni development in the vertebrate host, suggesting that adult parasites are more exposed to redox challenges than young stages. Indeed, adult parasites are exposed to multiple redox insults generated from blood digestion, activated immune cells, and, potentially, from their own parasitic aerobic metabolism. However, it remains unknown how reactive oxygen species are produced by S. mansoni metabolism, as well as their biological effects on adult worms. Here, we assessed the contribution of nutrients and parasite gender to oxygen utilization pathways, and reactive oxygen species generation in whole unpaired adult S. mansoni worms. We also determined the susceptibilities of both parasite sexes to a pro-oxidant challenge. We observed that glutamine and serum importantly contribute to both respiratory and non-respiratory oxygen utilization in adult worms, but with different proportions among parasite sexes. Analyses of oxygen utilization pathways revealed that respiratory rates were high in male worms, which contrast with high non-respiratory rates in females, regardless nutritional sources. Interestingly, mitochondrial complex I-III activity was higher than complex IV specifically in females. We also observed sexual preferences in substrate utilization to sustain hydrogen peroxide production towards glucose in females, and glutamine in male worms. Despite strikingly high oxidant levels and hydrogen peroxide production rates, female worms were more resistant to a pro-oxidant challenge than male parasites. The data presented here indicate that sexual preferences in nutrient metabolism in adult S. mansoni worms regulate oxygen utilization and reactive oxygen species production, which may differently contribute

  6. Minority Utility Rate Design Assessment Model

    2003-01-20

    Econometric model simulates consumer demand response to various user-supplied, two-part tariff electricity rate designs and assesses their economic welfare impact on black, hispanic, poor and majority households.

  7. Study of tissue oxygen supply rate in a macroscopic photodynamic therapy singlet oxygen model

    PubMed Central

    Zhu, Timothy C.; Liu, Baochang; Penjweini, Rozhin

    2015-01-01

    Abstract. An appropriate expression for the oxygen supply rate (Γs) is required for the macroscopic modeling of the complex mechanisms of photodynamic therapy (PDT). It is unrealistic to model the actual heterogeneous tumor microvascular networks coupled with the PDT processes because of the large computational requirement. In this study, a theoretical microscopic model based on uniformly distributed Krogh cylinders is used to calculate Γs=g (1−[O32]/[O32]0) that can replace the complex modeling of blood vasculature while maintaining a reasonable resemblance to reality; g is the maximum oxygen supply rate and [O32]/[O32]0 is the volume-average tissue oxygen concentration normalized to its value prior to PDT. The model incorporates kinetic equations of oxygen diffusion and convection within capillaries and oxygen saturation from oxyhemoglobin. Oxygen supply to the tissue is via diffusion from the uniformly distributed blood vessels. Oxygen can also diffuse along the radius and the longitudinal axis of the cylinder within tissue. The relations of Γs to [3O2]/[3O2]0 are examined for a biologically reasonable range of the physiological parameters for the microvasculature and several light fluence rates (ϕ). The results show a linear relationship between Γs and [3O2]/[3O2]0, independent of ϕ and photochemical parameters; the obtained g ranges from 0.4 to 1390  μM/s. PMID:25741665

  8. Plant respirometer enables high resolution of oxygen consumption rates

    NASA Technical Reports Server (NTRS)

    Foster, D. L.

    1966-01-01

    Plant respirometer permits high resolution of relatively small changes in the rate of oxygen consumed by plant organisms undergoing oxidative metabolism in a nonphotosynthetic state. The two stage supply and monitoring system operates by a differential pressure transducer and provides a calibrated output by digital or analog signals.

  9. Outcome measures for palliative oxygen therapy: relevance and practical utility.

    PubMed

    Antoniu, Sabina; Mihaltan, Florin

    2014-06-01

    Dyspnea is a common symptom in many advanced malignant and non-malignant diseases and often is refractory to the usual therapies. In such circumstances palliative care approaches are necessary and among them palliative care oxygen therapy can be applied although currently its effectiveness is rather uncertain. Palliative oxygen therapy can be given on either continuous basis or on demand. Often the continuous palliative oxygen therapy is seen as long-term oxygen therapy although their aims are rather different. Palliative oxygen therapy was evaluated in populations with mixed underlying diseases, with outcome measures not only the most appropriate for the setting and therefore these limitations might have influenced the overall perceived therapeutic benefit. Therefore an evaluation of this method in subsets defined based on the etiology and pathogenic mechanisms and with appropriate outcome measures would help to better define the criteria for its indication and would increase its acceptability. PMID:24741999

  10. Oxygen Mass Flow Rate Generated for Monitoring Hydrogen Peroxide Stability

    NASA Technical Reports Server (NTRS)

    Ross, H. Richard

    2002-01-01

    Recent interest in propellants with non-toxic reaction products has led to a resurgence of interest in hydrogen peroxide for various propellant applications. Because peroxide is sensitive to contaminants, material interactions, stability and storage issues, monitoring decomposition rates is important. Stennis Space Center (SSC) uses thermocouples to monitor bulk fluid temperature (heat evolution) to determine reaction rates. Unfortunately, large temperature rises are required to offset the heat lost into the surrounding fluid. Also, tank penetration to accomodate a thermocouple can entail modification of a tank or line and act as a source of contamination. The paper evaluates a method for monitoring oxygen evolution as a means to determine peroxide stability. Oxygen generation is not only directly related to peroxide decomposition, but occurs immediately. Measuring peroxide temperature to monitor peroxide stability has significant limitations. The bulk decomposition of 1% / week in a large volume tank can produce in excess of 30 cc / min. This oxygen flow rate corresponds to an equivalent temperature rise of approximately 14 millidegrees C, which is difficult to measure reliably. Thus, if heat transfer were included, there would be no temperature rise. Temperature changes from the surrounding environment and heat lost to the peroxide will also mask potential problems. The use of oxygen flow measurements provides an ultra sensitive technique for monitoring reaction events and will provide an earlier indication of an abnormal decomposition when compared to measuring temperature rise.

  11. Metabolically Derived human ventilation rates: A revised approach based upon oxygen consumption rates (Final Report) 2009

    EPA Science Inventory

    The purpose of this report is to provide a revised approach for calculating an individual's ventilation rate directly from their oxygen consumption rate. This revised approach will be used to update the ventilation rate information in the Exposure Factors Handbook, which serve as...

  12. The jumbo squid, Dosidicus gigas (Ommastrephidae), living in oxygen minimum zones I: Oxygen consumption rates and critical oxygen partial pressures

    NASA Astrophysics Data System (ADS)

    Trueblood, Lloyd A.; Seibel, Brad A.

    2013-10-01

    Dosidicus gigas is a large, metabolically active, epipelagic squid known to undertake diel vertical migrations across a large temperature and oxygen gradient in the Eastern Pacific. Hypoxia is known to cause metabolic suppression in D. gigas. However, the precise oxygen level at which metabolic suppression sets in is unknown. Here we describe a novel ship-board swim tunnel respirometer that was used to measure metabolic rates and critical oxygen partial pressures (Pcrit) for adult squids (2-7kg). Metabolic rate measurements were validated by comparison to the activity of the Krebs cycle enzyme, citrate synthase, in mantle muscle tissue (2-17kg). We recorded a mean routine metabolic rate of 5.91μmolg-1h-1 at 10°C and 12.62μmolg-1h-1 at 20°C. A temperature coefficient, Q10, of 2.1 was calculated. D. gigas had Pcrits of 1.6 and 3.8kPa at 10 and 20°C, respectively. Oxygen consumption rate (MO2) varied with body mass (M) according to MO2=11.57M-0.12±0.03 at 10°C. Citrate synthase activity varied with body mass according to Y=9.32M-0.19±0.02.

  13. Contaminant Removal from Oxygen Production Systems for In Situ Resource Utilization

    NASA Technical Reports Server (NTRS)

    Anthony, Stephen M.; Santiago-Maldonado, Edgardo; Captain, James G.; Pawate, Ashtamurthy S.; Kenis, Paul J. A.

    2012-01-01

    The In Situ Resource Utilization (ISRU) project has been developing technologies to produce oxygen from lunar regolith to provide consumables to a lunar outpost. The processes developed reduce metal oxides in the regolith to produce water, which is then electrolyzed to produce oxygen. Hydrochloic and hydrofluoric acids are byproducts of the reduction processes, as halide minerals are also reduced at oxide reduction conditions. Because of the stringent water quality requirements for electrolysis, there is a need for a contaminant removal process. The Contaminant Removal from Oxygen Production Systems (CROPS) team has been developing a separation process to remove these contaminants in the gas and liquid phase that eliminates the need for consumables. CROPS has been using Nafion, a highly water selective polymeric proton exchange membrane, to recover pure water from the contaminated solution. Membrane thickness, product stream flow rate, and acid solution temperature and concentration were varied with the goal of maximizing water permeation and acid rejection. The results show that water permeation increases with increasing solution temperature and product stream flow rate, while acid rejection increases with decreasing solution temperature and concentration. Thinner membranes allowed for higher water flux and acid rejection than thicker ones. These results were used in the development of the hardware built for the most recent Mars ISRU demonstration project.

  14. Burn propagation rates of metals and alloys in gaseous oxygen

    NASA Technical Reports Server (NTRS)

    Benz, F. J.; Shaw, R. C.; Homa, J. M.

    1986-01-01

    The average burn rates of several metals and alloys were determined at oxygen pressures between 3.45 and 68.91 MPa (500 and 10,000 psig) and ambient temperature. Several materials were tested at elevated sample temperatures. The test materials were fabricated into solid cylindrical rods and mounted vertically in the test chamber. A magnesium igniter was positioned at the bottom end of each test specimen to promote upward burn propagations. Nickel 200 and copper 102 could not be ignited at all oxygen pressures tested whereas Monel 400 appeared to ignite but quickly self-extinguished. The other materials tested burned the entire length of the test sample. Aluminum 6061 exhibited the fastest burn propagation rate. Inconel 718 burned slower than aluminum but faster than the stainless steels (types 304 and 316). Increasing oxygen pressure generally increased the burn propagation rate of the materials. Increasing the ambient temperature of the test specimens for several materials to approximately 850 K (1070 F) had little effect upon the ignition or burn properties of nickel 200 or Monel 400. Type 316 stainless steel exhibited an increase in its burn propagation rate at this higher temperature.

  15. Texturing Carbon-carbon Composite Radiator Surfaces Utilizing Atomic Oxygen

    NASA Technical Reports Server (NTRS)

    Raack, Taylor

    2004-01-01

    Future space nuclear power systems will require radiator technology to dissipate excess heat created by a nuclear reactor. Large radiator fins with circulating coolant are in development for this purpose and an investigation of how to make them most efficient is underway. Maximizing the surface area while minimizing the mass of such radiator fins is critical for obtaining the highest efficiency in dissipating heat. Processes to develop surface roughness are under investigation to maximize the effective surface area of a radiator fin. Surface roughness is created through several methods including oxidation and texturing. The effects of atomic oxygen impingement on carbon-carbon surfaces are currently being investigated for texturing a radiator surface. Early studies of atomic oxygen impingement in low Earth orbit indicate significant texturing due to ram atomic oxygen. The surface morphology of the affected surfaces shows many microscopic cones and valleys which have been experimentally shown to increase radiation emittance. Further study of this morphology proceeded in the Long Duration Exposure Facility (LDEF). Atomic oxygen experiments on the LDEF successfully duplicated the results obtained from materials in spaceflight by subjecting samples to 4.5 eV atomic oxygen from a fixed ram angle. These experiments replicated the conical valley morphology that was seen on samples subjected to low Earth orbit.

  16. Effective ionization rate in nitrogen-oxygen mixtures

    NASA Astrophysics Data System (ADS)

    Pancheshnyi, Sergey

    2013-04-01

    The effective Townsend ionization coefficient in nitrogen-oxygen mixtures at various pressures is determined. In addition to the commonly accepted difference of the ionization and the attachment coefficients, α and η, respectively, the electron detachment from the negative ions created by the avalanche itself is taken into account. This leads to non-zero effective ionization rate below the threshold field corresponding to α - η = 0.

  17. Effect of nuclear ownership on utility bond ratings and yields

    SciTech Connect

    Nesse, R.J.

    1982-02-01

    The major objective of this study was to test the hypothesis that investors have required an additional interest rate premium before purchasing bonds of utilities with large investments in nuclear facilities. The study required several tasks. First, the literature relating to firm bankruptcy and default was reviewed. Second, the failing financial health of the electric utility industry was assessed in terms of construction problems, the impact of federal and state regulations, and the impact of Three Mile Island. Finally, data were collected on 63 electric utilities. This allowed statistical estimation of the magnitude of the risk premium associated with utility involvement in nuclear power. The effect of this involvement on a utility's bond ratings was also examined. Multiple regression was the statistical tool used for the statistical testing and estimation.

  18. Utilization of oxygen difluoride for syntheses of fluoropolymers

    NASA Technical Reports Server (NTRS)

    Toy, M. S. (Inventor)

    1976-01-01

    The reaction oxygen difluoride, OF2, with ethylenically unsaturated fluorocarbon compounds is examined. Depending upon the fluorocarbon material and reaction conditions, OF2 can chain extend fluoropolyenes, convert functional perfluorovinyl groups to acyl fluoride and/or epoxide groups, and act as a monomer for an addition type copolymerization with diolefins.

  19. Utilization of Renewable Oxygenates as Gasoline Blending Components

    SciTech Connect

    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.

  20. Oxygen Consumption Rates of Bacteria under Nutrient-Limited Conditions

    PubMed Central

    Riedel, Timothy E.; Nealson, Kenneth H.; Finkel, Steven E.

    2013-01-01

    Many environments on Earth experience nutrient limitation and as a result have nongrowing or very slowly growing bacterial populations. To better understand bacterial respiration under environmentally relevant conditions, the effect of nutrient limitation on respiration rates of heterotrophic bacteria was measured. The oxygen consumption and population density of batch cultures of Escherichia coli K-12, Shewanella oneidensis MR-1, and Marinobacter aquaeolei VT8 were tracked for up to 200 days. The oxygen consumption per CFU (QO2) declined by more than 2 orders of magnitude for all three strains as they transitioned from nutrient-abundant log-phase growth to the nutrient-limited early stationary phase. The large reduction in QO2 from growth to stationary phase suggests that nutrient availability is an important factor in considering environmental respiration rates. Following the death phase, during the long-term stationary phase (LTSP), QO2 values of the surviving population increased with time and more cells were respiring than formed colonies. Within the respiring population, a subpopulation of highly respiring cells increased in abundance with time. Apparently, as cells enter LTSP, there is a viable but not culturable population whose bulk community and per cell respiration rates are dynamic. This result has a bearing on how minimal energy requirements are met, especially in nutrient-limited environments. The minimal QO2 rates support the extension of Kleiber's law to the mass of a bacterium (100-fg range). PMID:23770901

  1. Regional oxygen reduction and denitrification rates, San Joaquin Valley, USA

    NASA Astrophysics Data System (ADS)

    Green, C. T.; Jurgens, B. C.; Zhang, Y.; Starn, J. J.; Visser, A.; Singleton, M. J.; Esser, B. K.

    2015-12-01

    Rates of oxygen and nitrate reduction are key factors in determining the chemical evolution of groundwater. Little is known about how these rates vary in regional groundwater settings, as few studies have focused on regional datasets with multiple tracers and methods of analysis that account for effects of mixed residence times on apparent reaction rates. This study provides insight into residence times and rates of O2 reduction and denitrification using a novel approach of multi-model residence time distributions (RTDs) applied to a data set of atmospheric tracers of groundwater age and geochemical data from 141 well samples in the Central Eastern San Joaquin Valley, CA. The residence time distribution approach accounts for mixtures of residence times in a single sample to provide estimates of in-situ rates. Tracers included SF6, CFCs, 3H, He from 3H, 14C, and terrigenic He. Parameter estimation and multi-model averaging were used to establish RTDs with lower error variance than produced by individual RTD models. The set of multi-model RTDs was used in combination with NO3- and dissolved gas data to estimate zero order and first order rates of O2 reduction and denitrification. Results indicated that these rates followed approximately log-normal distributions. Rates of O2 reduction and denitrification were correlated and, on an electron milliequivalent basis, denitrification rates tended to exceed O2 reduction rates. Results indicate that the multi-model approach can improve estimation of age distributions, and that, because of the correlations, relatively easily measured O2 rates can provide information about trends in denitrification rates, which are more difficult to measure.

  2. Oxygen transfer rate and sophorose lipid production by Candida bombicola.

    PubMed

    Guilmanov, Vladimir; Ballistreri, Alberto; Impallomeni, Giuseppe; Gross, Richard A

    2002-03-01

    Sophorose lipids (SLs) have applications as surfactants and are produced at high levels by several yeasts. We developed a fed-batch shake-flask method for the production of SLs by Candida bombicola ATCC 22214. Optimal aeration, expressed in terms of oxygen transfer rate, was between 50 and 80 mM O(2)/L h(-1) and resulted in maximum values for both volumetric product formation (1-1.5 g/L h(-1)) and SL yield (350 g/L). The lowest aeration levels resulted in the enrichment in saturated fatty acid SLs at the expense of unsaturated fatty acid SLs. PMID:11788948

  3. Response of Microbial Soil Carbon Mineralization Rates to Oxygen Limitations

    NASA Astrophysics Data System (ADS)

    Keiluweit, M.; Denney, A.; Nico, P. S.; Fendorf, S. E.

    2014-12-01

    The rate of soil organic matter (SOM) mineralization is known to be controlled by climatic factors as well as molecular structure, mineral-organic associations, and physical protection. What remains elusive is to what extent oxygen (O2) limitations impact overall rates of microbial SOM mineralization (oxidation) in soils. Even within upland soils that are aerobic in bulk, factors limiting O2 diffusion such as texture and soil moisture can result in an abundance of anaerobic microsites in the interior of soil aggregates. Variation in ensuing anaerobic respiration pathways can further impact SOM mineralization rates. Using a combination of (first) aggregate model systems and (second) manipulations of intact field samples, we show how limitations on diffusion and carbon bioavailability interact to impose anaerobic conditions and associated respiration constraints on SOM mineralization rates. In model aggregates, we examined how particle size (soil texture) and amount of dissolved organic carbon (bioavailable carbon) affect O2 availability and distribution. Monitoring electron acceptor profiles (O2, NO3-, Mn and Fe) and SOM transformations (dissolved, particulate, mineral-associated pools) across the resulting redox gradients, we then determined the distribution of operative microbial metabolisms and their cumulative impact on SOM mineralization rates. Our results show that anaerobic conditions decrease SOM mineralization rates overall, but those are partially offset by the concurrent increases in SOM bioavailability due to transformations of protective mineral phases. In intact soil aggregates collected from soils varying in texture and SOM content, we mapped the spatial distribution of anaerobic microsites. Optode imaging, microsensor profiling and 3D tomography revealed that soil texture regulates overall O2 availability in aggregate interiors, while particulate SOM in biopores appears to control the fine-scale distribution of anaerobic microsites. Collectively, our

  4. Improved glucose utilization rate calculation by a recursive technique

    SciTech Connect

    Finn, E.J.; Brooks, R.A.; Di Chiro, G.

    1984-01-01

    When scanning with deoxyglucose, the crucial step in quantitation is the determination of glucose utilization rate, R, from tissue uptake data. R is conventionally calculated using nominal rate constants k/sub 1/-k/sub 4/, which are needed to correct for free deoxyglucose in the tissue at the time of the scan. In general, the resulting R is not consistent with these nominal rate constants, so the answer is necessarily in error. By adjusting the rate constants for consistency and then recalculating R, and repeating as necessary, an accuracy improvement should be obtained. The method reported here interates through modification of the third rate constant, k/sub 3/, since its value is determined by the hexokinase reaction which is considered to be the rate-limiting step. Data have been analyzed, taken from a representative sampling of the more than 150 patients scanned during the past year. It is seen that as glucose utilization rate moves away from the nominal rate for a subject, the self-consistency process developed by the iterative technique modified the quoted rate by an extra 2% per 10% change in R. Further, the percentage change in k/sub 3/ varies approximately linearly, but at a rate roughly twice that of the change in R. This modification indeed corresponds to an improvement in accuracy insofar as the enzymatic reaction described by k/sub 3/ is the primary source of change in glucose kinetics for the tissue in question. The same iterative procedure could be used with other assumptions about the way the rate constants vary.

  5. The Relationship between Heart Rate Reserve and Oxygen Uptake Reserve in Children and Adolescents

    ERIC Educational Resources Information Center

    Hui, Stanley Sai-chuen; Chan, Janus Wan-sze

    2006-01-01

    The purpose of the present study was to examine the relationship between oxygen uptake (VO[subscript 2]) and heart rate (HR) responses during rest and exercise in Chinese children and youth and to evaluate the relationships between maximal heart rate (%HRmax), heart rate reserve (%HRR), peak oxygen uptake (%VO[subscript 2]peak), and oxygen uptake…

  6. Programmable rate modem utilizing digital signal processing techniques

    NASA Technical Reports Server (NTRS)

    Naveh, Arad

    1992-01-01

    The need for a Programmable Rate Digital Satellite Modem capable of supporting both burst and continuous transmission modes with either Binary Phase Shift Keying (BPSK) or Quadrature Phase Shift Keying (QPSK) modulation is discussed. The preferred implementation technique is an all digital one which utilizes as much digital signal processing (DSP) as possible. The design trade-offs in each portion of the modulator and demodulator subsystem are outlined.

  7. Oxygen impacts on dipolarization fronts and reconnection rate

    NASA Astrophysics Data System (ADS)

    Liang, Haoming; Ashour-Abdalla, Maha; Lapenta, Giovanni; Walker, Raymond J.

    2016-02-01

    Spacecraft observations near a magnetotail X line show that oxygen (O+) ions are minor species during nonstorm substorms, but they can become major species during some of the storm time substorms. Dipolarization fronts (DFs), which are characterized by a sharp increase northward magnetic field in the magnetotail, are commonly observed during magnetospheric substorms. In this study, we investigated the O+ effects on DFs and the reconnection rate during magnetotail reconnection. We used a 2.5-D implicit particle-in-cell simulation in a 2-D Harris current sheet in the presence of H+ and O+ ions. Simulation runs with equal number densities of O+ and H+ (O+ run) and with pure H+ ion species (H+ run) were performed. Comparing the two different runs, we found that both the reconnection rate and the DF speed in the O+ run were much less than those in the H+ run. By studying the force balance and plasma composition at the DF, we found that the outflow magnetic flux and DF propagation were encumbered by the current sheet O+ inertia, which reduced the DF speed and delayed the reconnection rate in the O+ run. We also found an ambipolar electric field in the O+ run due to the different inflow and outflow speeds of O+ and electrons in the O+ diffusion region. As a result, this ambipolar electric field induced O+ drag on the convective magnetic field in the O+ diffusion region. The small reconnection rate determined in the O+ run can be attributed to the current sheet inertia and the O+ drag on the convective magnetic flux.

  8. Inhaled Oxygen for Cluster Headache: Efficacy, Mechanism of Action, Utilization, and Economics.

    PubMed

    Rozen, Todd D

    2012-01-29

    Inhaled normobaric oxygen is an essential abortive treatment of cluster headache. Recognition of its efficacy for cluster headache goes back a half a century, but very little has actually been written on the use of inhaled oxygen for cluster headache. This article examines various issues regarding inhaled oxygen and cluster headache, including efficacy, proposed mechanism of action, utilization, and the economics of oxygen usage for cluster headache patients. Much of the data analyzed comes from the recently published United States Cluster Headache Survey. This is the largest study of cluster headache patients ever published and is the first study to focus on inhaled oxygen and cluster headache in a large, non-clinic-based population. PMID:22286556

  9. Decrease in the etch rate of polymers in the oxygen afterglow with increasing gas flow rate

    NASA Technical Reports Server (NTRS)

    Lerner, N. R.; Wydeven, T.

    1988-01-01

    This paper reports the variation of the etch rate of polymers in the afterglow of a radio frequency discharge in oxygen as a function of total flow rate in the range 2-10 cu cm (STP)/min. The measurements were made at ambient temperature with the O(P-3) concentration held essentially constant. Results are reported on three polymers: cis-polybutadiene, a polybutadiene with 33 percent 1,2 double bonds, and a polybutadiene with 40 percent 1,2 double bonds. It has been observed that the etch rate of these polymers decreases significantly with increasing flow rate, strongly suggesting that the vapor-phase products of polymer degradation contribute to the degradation process.

  10. Eucalanoid copepod metabolic rates in the oxygen minimum zone of the eastern tropical north Pacific: Effects of oxygen and temperature

    NASA Astrophysics Data System (ADS)

    Cass, Christine J.; Daly, Kendra L.

    2014-12-01

    The eastern tropical north Pacific Ocean (ETNP) contains one of the world's most severe oxygen minimum zones (OMZs), where oxygen concentrations are less than 2 μmol kg-1. OMZs cause habitat compression, whereby species intolerant of low oxygen are restricted to near-surface oxygenated waters. Copepods belonging to the family Eucalanidae are dominant zooplankters in this region and inhabit a variety of vertical habitats within the OMZ. The purpose of this study was to compare the metabolic responses of three species of eucalanoid copepods, Eucalanus inermis, Rhincalanus rostrifrons, and Subeucalanus subtenuis, to changes in temperature and environmental oxygen concentrations. Oxygen consumption and urea, ammonium, and phosphate excretion rates were measured via end-point experiments at three temperatures (10, 17, and 23 °C) and two oxygen concentrations (100% and 15% air saturation). S. subtenuis, which occurred primarily in the upper 50 m of the water column at our study site, inhabiting well-oxygenated to upper oxycline conditions, had the highest metabolic rates per unit weight, while E. inermis, which was found throughout the water column to about 600 m depth in low oxygen waters, typically had the lowest metabolic rates. Rates for R. rostrifrons (found primarily between 200 and 300 m depth) were intermediate between the other two species and more variable. Metabolic ratios suggested that R. rostrifrons relied more heavily on lipids to fuel metabolism than the other two species. S. subtenuis was the only species that demonstrated a decrease in oxygen consumption rates (at intermediate 17 °C temperature treatment) when environmental oxygen concentrations were lowered. The percentage of total measured nitrogen excreted as urea (% urea-N), as well as overall urea excretion rates, responded in a complex manner to changes in temperature and oxygen concentration. R. rostrifrons and E. inermis excreted a significantly higher % of urea-N in low oxygen treatments at

  11. Self‐Rated Health Predicts Healthcare Utilization in Heart Failure

    PubMed Central

    Chamberlain, Alanna M.; Manemann, Sheila M.; Dunlay, Shannon M.; Spertus, John A.; Moser, Debra K.; Berardi, Cecilia; Kane, Robert L.; Weston, Susan A.; Redfield, Margaret M.; Roger, Véronique L.

    2014-01-01

    Background Heart failure (HF) patients experience impaired functional status, diminished quality of life, high utilization of healthcare resources, and poor survival. Yet, the identification of patient‐centered factors that influence prognosis is lacking. Methods and Results We determined the association of 2 measures of self‐rated health with healthcare utilization and skilled nursing facility (SNF) admission in a community cohort of 417 HF patients prospectively enrolled between October 2007 and December 2010 from Olmsted County, MN. Patients completed a 12‐item Short Form Health Survey (SF‐12). Low self‐reported physical functioning was defined as a score ≤25 on the SF‐12 physical component. The first question of the SF‐12 was used as a measure of self‐rated general health. After 2 years, 1033 hospitalizations, 1407 emergency department (ED) visits, and 19,780 outpatient office visits were observed; 87 patients were admitted to a SNF. After adjustment for confounding factors, an increased risk of hospitalizations (1.52 [1.17 to 1.99]) and ED visits (1.48 [1.04 to 2.11]) was observed for those with low versus moderate‐high self‐reported physical functioning. Patients with poor and fair self‐rated general health also experienced an increased risk of hospitalizations (poor: 1.73 [1.29 to 2.32]; fair: 1.46 [1.14 to 1.87]) and ED visits (poor: 1.73 [1.16 to 2.56]; fair: 1.48 [1.13 to 1.93]) compared with good‐excellent self‐rated general health. No association between self‐reported physical functioning or self‐rated general health with outpatient visits and SNF admission was observed. Conclusion In community HF patients, self‐reported measures of physical functioning predict hospitalizations and ED visits, indicating that these patient‐reported measures may be useful in risk stratification and management in HF. PMID:24870937

  12. A microwell array device capable of measuring single-cell oxygen consumption rates

    PubMed Central

    Molter, Timothy W.; McQuaide, Sarah C.; Suchorolski, Martin T.; Strovas, Tim J.; Burgess, Lloyd W.; Meldrum, Deirdre R.; Lidstrom, Mary E.

    2009-01-01

    Due to interest in cell population heterogeneity, the development of new technology and methodologies for studying single cells has dramatically increased in recent years. The ideal single cell measurement system would be high throughput for statistical relevance, would measure the most important cellular parameters, and minimize disruption of normal cell function. We have developed a microwell array device capable of measuring single cell oxygen consumption rates (OCR). This OCR device is able to diffusionally isolate single cells and enables the quantitative measurement of oxygen consumed by a single cell with fmol/min resolution in a non-invasive and relatively high throughput manner. A glass microwell array format containing fixed luminescent sensors allows for future incorporation of additional cellular parameter sensing capabilities. To demonstrate the utility of the OCR device, we determined the oxygen consumption rates of a small group of single cells (12 to 18) for three different cells lines: murine macrophage cell line RAW264.7, human epithelial lung cancer cell line A549, and human Barrett’s esophagus cell line CP-D. PMID:20084089

  13. [Design of Oxygen Saturation, Heart Rate, Respiration Rate Detection System Based on Smartphone of Android Operating System].

    PubMed

    Zhu, Mingshan; Zeng, Bixin

    2015-03-01

    In this paper, we designed an oxygen saturation, heart rate, respiration rate monitoring system based on smartphone of android operating system, physiological signal acquired by MSP430 microcontroller and transmitted by Bluetooth module. PMID:26524782

  14. Oxygen utilization of the human left ventricle - An indirect method for its evaluation and clinical considerations

    NASA Technical Reports Server (NTRS)

    Ghista, D. N.; Sandler, H.

    1974-01-01

    An analytical method is presented for determining the oxygen consumption rate of the intact heart working (as opposed to empty but beating) human left ventricle. Use is made of experimental recordings obtained for the chamber pressure and the associated dimensions of the LV. LV dimensions are determined by cineangiocardiography, and the chamber pressure is obtained by means of fluid-filled catheters during retrograde or transeptal catheterization. An analytical method incorporating these data is then employed for the evaluation of the LV coronary oxygen consumption in five subjects. Oxygen consumption for these subjects was also obtained by the conventional clinical method in order to evaluate the reliability of the proposed method.

  15. Programmable rate modem utilizing digital signal processing techniques

    NASA Technical Reports Server (NTRS)

    Bunya, George K.; Wallace, Robert L.

    1989-01-01

    The engineering development study to follow was written to address the need for a Programmable Rate Digital Satellite Modem capable of supporting both burst and continuous transmission modes with either binary phase shift keying (BPSK) or quadrature phase shift keying (QPSK) modulation. The preferred implementation technique is an all digital one which utilizes as much digital signal processing (DSP) as possible. Here design tradeoffs in each portion of the modulator and demodulator subsystem are outlined, and viable circuit approaches which are easily repeatable, have low implementation losses and have low production costs are identified. The research involved for this study was divided into nine technical papers, each addressing a significant region of concern in a variable rate modem design. Trivial portions and basic support logic designs surrounding the nine major modem blocks were omitted. In brief, the nine topic areas were: (1) Transmit Data Filtering; (2) Transmit Clock Generation; (3) Carrier Synthesizer; (4) Receive AGC; (5) Receive Data Filtering; (6) RF Oscillator Phase Noise; (7) Receive Carrier Selectivity; (8) Carrier Recovery; and (9) Timing Recovery.

  16. Seasonal Oxygen Dynamics in a Thermokarst Bog in Interior Alaska: Implications for Rates of Methane Oxidation

    NASA Astrophysics Data System (ADS)

    Neumann, R. B.; Moorberg, C.; Wong, A.; Waldrop, M. P.; Turetsky, M. R.

    2015-12-01

    Methane is a potent greenhouse gas, and wetlands represent the largest natural source of methane to the atmosphere. However, much of the methane generated in anoxic wetlands never gets emitted to the atmosphere; up to >90% of generated methane can get oxidized to carbon dioxide. Thus, oxidation is an important methane sink and changes in the rate of methane oxidation can affect wetland methane emissions. Most methane is aerobically oxidized at oxic-anoxic interfaces where rates of oxidation strongly depend on methane and oxygen concentrations. In wetlands, oxygen is often the limiting substrate. To improve understanding of belowground oxygen dynamics and its impact on methane oxidation, we deployed two planar optical oxygen sensors in a thermokarst bog in interior Alaska. Previous work at this site indicated that, similar to other sites, rates of methane oxidation decrease over the growing season. We used the sensors to track spatial and temporal patterns of oxygen concentrations over the growing season. We coupled these in-situ oxygen measurements with periodic oxygen injection experiments performed against the sensor to quantify belowground rates of oxygen consumption. We found that over the season, the thickness of the oxygenated water layer at the peatland surface decreased. Previous research has indicated that in sphagnum-dominated peatlands, like the one studied here, rates of methane oxidation are highest at or slightly below the water table. It is in these saturated but oxygenated locations that both methane and oxygen are available. Thus, a seasonal reduction in the thickness of the oxygenated water layer could restrict methane oxidation. The decrease in thickness of the oxygenated layer coincided with an increase in the rate of oxygen consumption during our oxygen injection experiments. The increase in oxygen consumption was not explained by temperature; we infer it was due to an increase in substrate availability for oxygen consuming reactions and

  17. Influence of myocardial substrate utilization on the oxygen consumption of the heart.

    PubMed

    Kahles, H; Hellige, G; Hunneman, D H; Mezger, V A; Bretschneider, H J

    1982-04-01

    The effect of changing myocardial metabolism from predominantly lipid to predominantly carbohydrate utilization on myocardial oxygen consumption (MVO2) was studied in 10 closed-chest dogs. Oxygen saving potency of different metabolic interventions was quantified over a wide hemodynamic range by comparing the directly determined MVO2 with the hemodynamic parameter total left ventricular energy demand (Et), which correlates closely under control conditions with MVO2 (r = 0.98). Stimulation of carbohydrate metabolism by addition of glucose and beta-pyridyl carbinol or by activation of pyruvate dehydrogenase with dichloroacetate (DCA) shifted the cardiac respiratory quotient during beta-stimulation from 0.73 to 1.00 and 0.89, respectively, the nonesterified fatty acid/albumin ratio decreased from 4.0 to 0.5, or remained unchanged with DCA, and MVO2 was reduced by 25 and 16%, respectively. Therapeutic approaches aimed at decreasing MVO2 by changing substrate utilization are discussed. PMID:7083652

  18. A New Approach for Measuring Single-Cell Oxygen Consumption Rates

    PubMed Central

    Molter, Timothy W.; McQuaide, Sarah C.; Holl, Mark R.; Meldrum, Deirdre R.; Dragavon, Joseph M.; Anderson, Judith B.; Young, A. Cody; Burgess, Lloyd W.; Lidstrom, Mary E.

    2010-01-01

    A novel system that has enabled the measurement of single-cell oxygen consumption rates is presented. The experimental apparatus includes a temperature controlled environmental chamber, an array of microwells etched in glass, and a lid actuator used to seal cells in the microwells. Each microwell contains an oxygen sensitive platinum phosphor sensor used to monitor the cellular metabolic rates. Custom automation software controls the digital image data collection for oxygen sensor measurements, which are analyzed using an image-processing program to yield the oxygen concentration within each microwell versus time. Two proof-of-concept experiments produced oxygen consumption rate measurements for A549 human epithelial lung cancer cells of 5.39 and 5.27 fmol/min/cell, closely matching published oxygen consumption rates for bulk A549 populations. PMID:21057593

  19. Guidelines for the Utilization of Composite Materials in Oxygen Storage Tanks

    NASA Technical Reports Server (NTRS)

    Davis, Samuel E.; Herald, Stephen

    2006-01-01

    Space travel is inherently dangerous and, currently, quite expensive. NASA has always done everything possible to minimize the risk associated with the materials chosen for space travel applications by requiring that all materials associated with NASA programs meet the strict requirements established by NASA testing standard NASA-STD-600 1 Flammability, Odor, Offgassing, and Compatibility Requirements and Test Procedures for Materials in Environments that Support Combustion. NASA also has the need to develop lighter weight structural materials that will allow more payload weight to be carried into space. NASA is utilizing composite materials inside the orbiter to lighten the overall weight, but has not considered composite materials for oxygen tanks because of the inherent incompatibility of composite materials with atomic oxygen. This presentation will focus on how oxygen tanks can be built from composite materials. Details will be provided for the design and compatibility testing techniques that will be utilized to create a new NASA standard, NASA-HDBK-6018, which will serve as the starting point for the design of oxygen tanks made from composite materials.

  20. Is the surface oxygen exchange rate linked to bulk ion diffusivity in mixed conducting Ruddlesden–Popper phases?

    DOE PAGESBeta

    Tomkiewicz, Alex C.; Tamimi, Mazin A.; Huq, Ashfia; McIntosh, Steven

    2015-03-02

    There is a possible link between oxygen surface exchange rate and bulk oxygen anion diffusivity in mixed ionic and electronic conducting oxides; it is a topic of great interest and debate. While a large body of experimental evidence and theoretical analyses support a link, observed differences between bulk and surface composition of these materials are hard to reconcile with this observation. This is further compounded by potential problems with simultaneous measurement of both parameters. Here we utilize separate techniques, in situ neutron diffraction and pulsed isotopic surface exchange, to examine bulk ion mobility and surface oxygen exchange rates of threemore » Ruddlesden-Popper phases, general form An-1A2'BnO3n+1, An-1A2'BnX3n+1; LaSrCo0.5Fe0.5O4-δ (n = 1), La0.3Sr2.7CoFeO7-δ (n = 2) and LaSr3Co1.5Fe1.5O10-δ (n = 3). These measurements are complemented by surface composition determination via high sensitivity-low energy ion scattering. We observe a correlation between bulk ion mobility and surface exchange rate between materials. The surface exchange rates vary by more than one order of magnitude with high anion mobility in the bulk of an oxygen vacancy-rich n = 2 Ruddlesden-Popper material correlating with rapid oxygen exchange. Furthermore this is in contrast with the similar surface exchange rates which we may expect due to similar surface compositions across all three samples. This paper conclude that experimental limitations lead to inherent convolution of surface and bulk rates, and that surface exchange steps are not likely to be rate limiting in oxygen incorporation.« less

  1. Determining oxygen consumption rate and asphyxiation point in Chanodichthys mongolicus using an improved respirometer chamber

    NASA Astrophysics Data System (ADS)

    Geng, Longwu; Jiang, Haifeng; Tong, Guangxiang; Xu, Wei

    2016-05-01

    Knowledge of oxygen consumption rates and asphyxiation points in fish is important to determine appropriate stocking and water quality management in aquaculture. The oxygen consumption rate and asphyxiation point in Chanodichthys mongolicus were detected under laboratory conditions using an improved respirometer chamber. The results revealed that more accurate estimates can be obtained by adjusting the volume of the respirometer chamber, which may avoid system errors caused by either repeatedly adjusting fish density or selecting different equipment specifications. The oxygen consumption rate and asphyxiation point of C. mongolicus increased with increasing water temperature and decreasing fish size. Changes in the C. mongolicus oxygen consumption rate were divided into three stages at water temperatures of 11-33°C: (1) a low temperature oxygen consumption rate stage when water temperature was 11-19°C, (2) the optimum temperature oxygen consumption rate stage when water temperature was 19-23°C, and (3) a high temperature oxygen consumption rate stage when water temperature was > 27°C. The temperature quotients (Q10) obtained suggested that C. mongolicus preferred a temperature range of 19-23°C. At 19°C, C. mongolicus exhibited higher oxygen consumption rates during the day when the maximum values were observed at 10:00 and 14:00 than at night when the minimum occurred at 02:00.

  2. Oxygen Consumption and Substrate Utilization During and After Resistance Exercises Performed with Different Muscle Mass

    PubMed Central

    FARINATTI, PAULO; CASTINHEIRAS NETO, ANTONIO G.; AMORIM, PAULO R.S.

    2016-01-01

    This study investigated the energy expenditure (EE) and substrate utilization reflected by the respiratory-exchange ratio (RER) during and after resistance exercises performed with different muscle mass. Ten male volunteers (mean±SD; 26±4yr, 179±6cm, 77±8kg) performed multiple sets of the horizontal leg press (LP) and chest fly (CF) (5 sets of 10 repetitions with 15 repetition-maximum, 1-minute between-set intervals) in a counterbalanced design. Oxygen uptake and carbon dioxide production were measured during 40 minutes of resting; resistance exercise protocols (sets and intervals); 90 minutes of post-exercise recovery. Total fat and carbohydrate oxidation rates were calculated according to the non-protein respiratory quotient. Both exercise conditions elicited net excess post-exercise oxygen consumption (EPOC) of similar duration (approximately 40min). The EPOC magnitude at 40 minutes was greater after LP than after CF (7.36±1.10L vs. 4.73±0.99L; P<0.001). The RER was higher in LP (1.30±0.04) than CF (1.16±0.05, P=0.0003) during exercise. During recovery the RER was similar in LP and CF (P>0.05) and lower than pre-exercise (Pre-exercise=0.78±0.04 vs. CF40min=0.74±0.04; CF90min=0.68±0.02 and LP50min=0.73±0.06; LP90min=0.65±0.04, P<0.05). However, fat oxidation after LP was greater than CF between 30–90 minutes of recovery (mean total fat oxidation: LP=10.9 g vs. CF=8.4 g; P<0.01). The increases of EE and fat oxidation during post-exercise recovery were greater after multiple sets of resistance exercises performed with larger muscle mass than smaller muscle mass. This finding has practical implications for resistance training designed as part of weight management programs. PMID:27293507

  3. On the Utility of the Molecular Oxygen Dayglow Emissions as Proxies for Middle Atmospheric Ozone

    NASA Technical Reports Server (NTRS)

    Mlynczak, Martin G.; Olander, Daphne S.

    1995-01-01

    Molecular oxygen dayglow emissions arise in part from processes related to the Hartley band photolysis of ozone. It is therefore possible to derive daytime ozone concentrations from measurements of the volume emission rate of either dayglow. The accuracy to which the ozone concentration can be inferred depends on the accuracy to which numerous kinetic and spectroscopic rate constants are known, including rates which describe the excitation of molecular oxygen by processes that are not related to the ozone concentration. We find that several key rate constants must be known to better than 7 percent accuracy in order to achieve an inferred ozone concentration accurate to 15 percent from measurements of either dayglow. Currently, accuracies for various parameters typically range from 5 to 100 percent.

  4. Improved myocardial oxygen utilization following propranolol infusion in adolescents with postburn hypermetabolism.

    PubMed

    Minifee, P K; Barrow, R E; Abston, S; Desai, M; Herndon, D N

    1989-08-01

    The purpose of this study was to determine if propranolol (0.5 mg/kg and 1 mg/kg), administered intravenously (IV) at the height of the postburn hypermetabolic response, would decrease myocardial oxygen requirements, without adversely affecting overall oxygen delivery or total body oxygen consumption. To test this hypothesis, six nonseptic patients age 17 +/- 3 years with burns over 82% +/- 11% total body surface area were given propranolol with continuous hemodynamic monitoring. Propranolol was administered to these patients 20 +/- 15 days postburn. Two clinically derived indices of myocardial oxygen consumption, pressure-work index (PWI) and rate-pressure product (RPP), were used to estimate the energy expenditure of the working heart. Both PWI and RPP were significantly decreased from baseline after 0.5 mg/kg propranolol, 31% for PWI (P less than .001) and 30% for RPP (P less than .01). Similarly, a decrease from baseline was seen after 1.0 mg/kg propranolol, 32% for PWI (P less than .001) and 35% for RPP (P less than .01). Cardiac index (L/min/m2) demonstrated no significant change [7.4 +/- 1.1 (prepropranolol), 6.5 +/- 1.3 (after 0.5 mg/kg propranolol), and 6.8 +/- 1.0 (after 1.0 mg/kg propranolol)] and exceeded the upper limits of normal (hyperdynamic state) throughout the study. Oxygen delivery index (962 +/- 209 mL/min/m2) and oxygen consumption indices [(254 +/- 78 mL/min/m2 by Fick method and 236 +/- 78 mL/min/m2 by inspired and expired gases)] were elevated at baseline and unaffected by propranolol. The decrease in PWI and RPP was achieved mainly by propranolol's effect to lower both heart rate and BP.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2769550

  5. Optimization of 2,3-butanediol production by Klebsiella oxytoca through oxygen transfer rate control

    SciTech Connect

    Beronio, P.B. Jr. . Amoco Research Center); Tsao, G.T. . Lab. of Renewable Resources Engineering)

    1993-12-01

    Production of 2,3-butanediol by Klebsiella oxytoca is influenced by the degree of oxygen limitation. During batch culture studies, two phases of growth are observed: energy-coupled growth, during which cell growth and oxygen supply are coupled; and, energy-uncoupled growth, which arises when the degree of oxygen limitation reaches a critical value. Optimal 2,3-butanediol productivity occurs during the energy-coupled growth phase. In this article, a control system which maintains the batch culture at a constant level of oxygen limitation in the energy-coupled growth regime has been designed. Control, which involves feedback control on the oxygen transfer coefficient, is achieved by continually increasing the partial pressure of oxygen in the feed gas, which in turn continually increases the oxygen transfer rate. Control has resulted in a balanced state of growth, a repression of ethanol formation, and an increase in 2,3-butanediol productivity of 18%.

  6. Metabolically-Derived Human Ventilation Rates: A Revised Approach Based Upon Oxygen Consumption Rates (External Review Draft)

    EPA Science Inventory

    EPA has released a draft report entitled, Metabolically-Derived Human Ventilation Rates: A Revised Approach Based Upon Oxygen Consumption Rates, for independent external peer review and public comment. NCEA published the Exposure Factors Handbook in 1997. This comprehens...

  7. GRAPHITE ELECTRODE FOR THE MEASUREMENT OF REDOX POTENTIAL AND OXYGEN DIFFUSION RATE IN SOIL

    EPA Science Inventory

    The objective of the project was to evaluate control measurements that might be made at land treatment sites to determine the effectiveness of operation in the management of hazardous wastes. Initial studies were on measurement of oxygen concentration and oxygen diffusion rate (O...

  8. Coevaporation of Y, BaF sub 2 , and Cu utilizing a quadrupole mass spectrometer as a rate measuring probe

    SciTech Connect

    Hudner, J.; Oestling, M. ); Ohlsen, H.; Stolt, L. )

    1991-09-01

    An ultrahigh vacuum coevaporator equipped with three sources for preparation of Y--BaF{sub 2} --Cu--O thin films is described. Evaporation rates of Y, BaF{sub 2}, and Cu were controlled using a quadrupole mass spectrometer operating in a multiplexed mode. To evaluate the method depositions have been performed using different source configurations and evaporation rates. Utilizing Rutherford backscattering spectrometry absolute values of the actual evaporation rates were determined. It was observed that the mass-spectrometer sensitivity is highest for Y, followed by BaF{sub 2} (BaF{sup +} is the measured ion) and Cu. A partial pressure of oxygen during evaporation of Y, BaF{sub 2}, and Cu affected mainly the rate of Y. It is shown that the mass spectrometer can be utilized to precisely control the film composition.

  9. Effects of cardiopulmonary bypass on gut blood flow, oxygen utilization, and intramucosal pH.

    PubMed

    Ohri, S K; Becket, J; Brannan, J; Keogh, B E; Taylor, K M

    1994-05-01

    Studies documenting rises in endotoxin after cardiopulmonary bypass (CPB) have postulated gut mucosal hypoperfusion. We have investigated alterations in jejunal blood flow by laser Doppler flow measurement, intramucosal pH (pHi) by tonometry, and oxygen utilization in a canine model of hypothermic CPB (n = 11 dogs). After 10 minutes of hypothermic CPB, despite no major reduction in superior mesenteric artery flow, mucosal laser Doppler flow decreased to -38.2% +/- 9.3% of levels obtained before bypass (p = 0.008) and serosal laser Doppler flow, to -47.3% +/- 11.4% (p = 0.006). During the hypothermic phase, mesenteric oxygen consumption fell from 0.18 +/- 0.01 to 0.098 +/- 0.01 mL.min-1.kg-1 (p = 0.005), and mesenteric oxygen delivery fell from 1.97 +/- 0.39 to 1.14 +/- 0.12 mL.min-1.kg-1 (p = 0.05). There was no change in jejunal pHi. During the rewarming phase, there was a substantial increase in mucosal laser Doppler flow, peaking at +69.8% +/- 15.2% (p = 0.03), whereas serosal laser Doppler flow returned to values seen prior to CPB (-16.4% +/- 21.5%; p = 0.25). These changes coincided with a surge in oxygen consumption (0.33 +/- 0.042 mL.min-1.kg-1; p = 0.009), while mesenteric oxygen delivery remained depressed at 1.09 +/- 0.12 mL.min-1.kg-1 (p = 0.04). Jejunal pHi fell from a value of 7.36 +/- 0.04 before CPB to 7.12 +/- 0.07 (p = 0.02), thus indicating mucosal hypoxia. During the rewarming phase of hypothermic CPB, there is a disparity between mesenteric oxygen consumption and oxygen delivery with villus tip ischemia; these findings may explain the pathophysiology of endotoxemia during CPB. PMID:8179384

  10. Attrition Rate of Oxygen Carriers in Chemical Looping Combustion Systems

    NASA Astrophysics Data System (ADS)

    Feilen, Harry Martin

    This project developed an evaluation methodology for determining, accurately and rapidly, the attrition resistance of oxygen carrier materials used in chemical looping technologies. Existing test protocols, to evaluate attrition resistance of granular materials, are conducted under non-reactive and ambient temperature conditions. They do not accurately reflect the actual behavior under the unique process conditions of chemical looping, including high temperatures and cyclic operation between oxidizing and reducing atmospheres. This project developed a test method and equipment that represented a significant improvement over existing protocols. Experimental results obtained from this project have shown that hematite exhibits different modes of attrition, including both due to mechanical stresses and due to structural changes in the particles due to chemical reaction at high temperature. The test methodology has also proven effective in providing reactivity changes of the material with continued use, a property, which in addition to attrition, determines material life. Consumption/replacement cost due to attrition or loss of reactivity is a critical factor in the economic application of the chemical looping technology. This test method will allow rapid evaluation of a wide range of materials that are best suited for this technology. The most important anticipated public benefit of this project is the acceleration of the development of chemical looping technology for lowering greenhouse gas emissions from fossil fuel combustion.

  11. Absolute rate parameters for the reaction of ground state atomic oxygen with dimethyl sulfide and episulfide

    NASA Technical Reports Server (NTRS)

    Lee, J. H.; Timmons, R. B.; Stief, L. J.

    1976-01-01

    It is pointed out that the investigated reaction of oxygen with dimethyl sulfide may play an important role in photochemical smog formation and in the chemical evolution of dense interstellar clouds. Kinetic data were obtained with the aid of the flash photolysis-resonance fluorescence method. The photodecomposition of molecular oxygen provided the oxygen atoms for the experiments. The decay of atomic oxygen was studied on the basis of resonance fluorescence observations. Both reactions investigated were found to be fast processes. A negative temperature dependence of the rate constants for reactions with dimethyl sulfide was observed.

  12. A numerical investigation of oxygen concentration dependence on biodegradation rate laws in vapor intrusion

    PubMed Central

    Yao, Yijun; Shen, Rui; Pennel, Kelly G.; Suuberg, Eric M.

    2013-01-01

    In subsurface vapor intrusion, aerobic biodegradation has been considered as a major environmental factor that determines the soil gas concentration attenuation factors for contaminants such as petroleum hydrocarbons. The site investigation showed that oxygen could play an important role in this biodegradation rate, and this paper explores the influence of oxygen concentration in biodegradation reactions included in vapor intrusion (VI) models. Two different three dimensional (3-D) numerical models of vapor intrusion were explored for their sensitivity to the form of the biodegradation rate law. A second order biodegradation rate law, explicitly including oxygen concentration dependence, was introduced into one model. The results indicate that the aerobic/anoxic interface depth is determined by the ratio of contaminant source vapor to atmospheric oxygen concentration, and that the contaminant concentration profile in the aerobic zone was significantly influenced by the choice of rate law. PMID:24197079

  13. A numerical investigation of oxygen concentration dependence on biodegradation rate laws in vapor intrusion.

    PubMed

    Yao, Yijun; Shen, Rui; Pennel, Kelly G; Suuberg, Eric M

    2013-12-01

    In subsurface vapor intrusion, aerobic biodegradation has been considered as a major environmental factor that determines the soil gas concentration attenuation factors for contaminants such as petroleum hydrocarbons. The site investigation has shown that oxygen can play an important role in this biodegradation rate, and this paper explores the influence of oxygen concentration on biodegradation reactions included in vapor intrusion (VI) models. Two different three dimensional (3-D) numerical models of vapor intrusion were explored for their sensitivity to the form of the biodegradation rate law. A second order biodegradation rate law, explicitly including oxygen concentration dependence, was introduced into one model. The results indicate that the aerobic/anoxic interface depth is determined by the ratio of contaminant source vapor to atmospheric oxygen concentration, and that the contaminant concentration profile in the aerobic zone was significantly influenced by the choice of rate law. PMID:24197079

  14. Noninvasive optical quantification of absolute blood flow, blood oxygenation, and oxygen consumption rate in exercising skeletal muscle.

    PubMed

    Gurley, Katelyn; Shang, Yu; Yu, Guoqiang

    2012-07-01

    This study investigates a method using novel hybrid diffuse optical spectroscopies [near-infrared spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS)] to obtain continuous, noninvasive measurement of absolute blood flow (BF), blood oxygenation, and oxygen consumption rate (V̇O(2)) in exercising skeletal muscle. Healthy subjects (n=9) performed a handgrip exercise to increase BF and V̇O(2) in forearm flexor muscles, while a hybrid optical probe on the skin surface directly monitored oxy-, deoxy-, and total hemoglobin concentrations ([HbO(2)], [Hb], and THC), tissue oxygen saturation (S(t)O(2)), relative BF (rBF), and relative oxygen consumption rate (rV̇O(2)). The rBF and rV̇O(2) signals were calibrated with absolute baseline BF and V̇O(2) obtained through venous and arterial occlusions, respectively. Known problems with muscle-fiber motion artifacts in optical measurements during exercise were mitigated using a novel gating algorithm that determined muscle contraction status based on control signals from a dynamometer. Results were consistent with previous findings in the literature. This study supports the application of NIRS/DCS technology to quantitatively evaluate hemodynamic and metabolic parameters in exercising skeletal muscle and holds promise for improving diagnosis and treatment evaluation for patients suffering from diseases affecting skeletal muscle and advancing fundamental understanding of muscle and exercise physiology. PMID:22894482

  15. Noninvasive optical quantification of absolute blood flow, blood oxygenation, and oxygen consumption rate in exercising skeletal muscle

    PubMed Central

    Gurley, Katelyn; Shang, Yu

    2012-01-01

    Abstract. This study investigates a method using novel hybrid diffuse optical spectroscopies [near-infrared spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS)] to obtain continuous, noninvasive measurement of absolute blood flow (BF), blood oxygenation, and oxygen consumption rate (V˙O2) in exercising skeletal muscle. Healthy subjects (n=9) performed a handgrip exercise to increase BF and V˙O2 in forearm flexor muscles, while a hybrid optical probe on the skin surface directly monitored oxy-, deoxy-, and total hemoglobin concentrations ([HbO2], [Hb], and THC), tissue oxygen saturation (StO2), relative BF (rBF), and relative oxygen consumption rate (rV˙O2). The rBF and rV˙O2 signals were calibrated with absolute baseline BF and V˙O2 obtained through venous and arterial occlusions, respectively. Known problems with muscle-fiber motion artifacts in optical measurements during exercise were mitigated using a novel gating algorithm that determined muscle contraction status based on control signals from a dynamometer. Results were consistent with previous findings in the literature. This study supports the application of NIRS/DCS technology to quantitatively evaluate hemodynamic and metabolic parameters in exercising skeletal muscle and holds promise for improving diagnosis and treatment evaluation for patients suffering from diseases affecting skeletal muscle and advancing fundamental understanding of muscle and exercise physiology. PMID:22894482

  16. Noninvasive optical quantification of absolute blood flow, blood oxygenation, and oxygen consumption rate in exercising skeletal muscle

    NASA Astrophysics Data System (ADS)

    Gurley, Katelyn; Shang, Yu; Yu, Guoqiang

    2012-07-01

    This study investigates a method using novel hybrid diffuse optical spectroscopies [near-infrared spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS)] to obtain continuous, noninvasive measurement of absolute blood flow (BF), blood oxygenation, and oxygen consumption rate (\\Vdot O2) in exercising skeletal muscle. Healthy subjects (n=9) performed a handgrip exercise to increase BF and \\Vdot O2 in forearm flexor muscles, while a hybrid optical probe on the skin surface directly monitored oxy-, deoxy-, and total hemoglobin concentrations ([HbO2], [Hb], and THC), tissue oxygen saturation (StO2), relative BF (rBF), and relative oxygen consumption rate (r\\Vdot O2). The rBF and r\\Vdot O2 signals were calibrated with absolute baseline BF and \\Vdot O2 obtained through venous and arterial occlusions, respectively. Known problems with muscle-fiber motion artifacts in optical measurements during exercise were mitigated using a novel gating algorithm that determined muscle contraction status based on control signals from a dynamometer. Results were consistent with previous findings in the literature. This study supports the application of NIRS/DCS technology to quantitatively evaluate hemodynamic and metabolic parameters in exercising skeletal muscle and holds promise for improving diagnosis and treatment evaluation for patients suffering from diseases affecting skeletal muscle and advancing fundamental understanding of muscle and exercise physiology.

  17. High rate PLD of diamond-like-carbon utilizing high repetition rate visible lasers

    SciTech Connect

    McLean, W. II; Fehring, E.J.; Dragon, E.P.; Warner, B.E.

    1994-09-15

    Pulsed Laser Deposition (PLD) has been shown to be an effective method for producing a wide variety of thin films of high-value-added materials. The high average powers and high pulse repetition frequencies of lasers under development at LLNL make it possible to scale-up PLD processes that have been demonstrated in small systems in a number of university, government, and private laboratories to industrially meaningful, economically feasible technologies. A copper vapor laser system at LLNL has been utilized to demonstrate high rate PLD of high quality diamond-like-carbon (DLC) from graphite targets. The deposition rates for PLD obtained with a 100 W laser were {approx} 2000 {mu}m{center_dot}cm{sup 2}/h, or roughly 100 times larger than those reported by chemical vapor deposition (CVD) or physical vapor deposition (PVD) methods. Good adhesion of thin (up to 2 pm) films has been achieved on a small number of substrates that include SiO{sub 2} and single crystal Si. Present results indicate that the best quality DLC films can be produced at optimum rates at power levels and wavelengths compatible with fiber optic delivery systems. If this is also true of other desirable coating systems, this PLD technology could become an extremely attractive industrial tool for high value added coatings.

  18. Effects of positional restraint on oxygen saturation and heart rate following exercise.

    PubMed

    Reay, D T; Howard, J D; Fligner, C L; Ward, R J

    1988-03-01

    This report assesses the effects on peripheral oxygen saturation and heart rate that positional restraint induces when a person is prone, handcuffed, and "hog-tied." Peripheral oxygen saturation and heart rate were monitored at rest, during exercise, and during recovery from exercise for 10 adult subjects. The effects of positional restraint produced a mean recovery time that was significantly prolonged. Consequently, the physiological effects produced by positional restraint should be recognized in deaths where such measures are used. PMID:3354518

  19. Rate of reaction between molecular hydrogen and molecular oxygen

    NASA Technical Reports Server (NTRS)

    Brokaw, R. S.

    1973-01-01

    The shock tube data of Jachimowski and Houghton were rigorously analyzed to obtain rate constants for the candidate initiation reactions H2 + O2 yields H + HO2, H2 + O2 yields H2O + O, and H2 + O2 yields OH + OH. Reaction (01) is probably not the initiation process because the activation energy obtained is less than the endothermicity and because the derived rates greatly exceed values inferred in the literature from the reverse of reaction (01). Reactions (02) and (03) remain as possibilities, with reaction (02) slightly favored on the basis of steric and statistical considerations. The solution of the differential equations is presented in detail to show how the kinetics of other ignition systems may be solved.

  20. Oxygen Ion Heat Rate within Alfvenic Turbulence in the Cusp

    NASA Technical Reports Server (NTRS)

    Coffey, Victoria N.; Singh, Nagendra; Chandler, Michael O.

    2009-01-01

    The role that the cleft/cusp has in ionosphere-magnetosphere coupling makes it a dynamic and important region. It is directly exposed to the solar wind, making it possible for the entry of electromagnetic energy and precipitating electrons and ions from dayside reconnection and other dayside events. It is also a significant source of ionospheric plasma, contributing largely to the mass loading of the magnetosphere with large fluxes of outflowing ions. Crossing the cusp/cleft near 5100 km, the Polar instruments observe the common correlation of downward Poynting flux, ion energization, soft electron precipitation, broadband extremely low-frequency (BB-ELF) emissions, and density depletions. The dominant power in the BB-ELF emissions is now identified to be from spatially broad, low frequency Alfv nic structures. For a cusp crossing, we determine using the Electric Field Investigation (EFI), that the electric and magnetic field fluctuations are Alfv nic and the electric field gradients satisfy the inequality for stochastic acceleration. With all the Polar 1996 horizontal crossings of the cusp, we determine the O+ heating rate using the Thermal Ion Dynamics Experiment (TIDE) and Plasma Wave Investigation (PWI). We then compare this heating rate to other heating rates assuming the electric field gradient criteria exceeds the limit for stochastic acceleration for the remaining crossings. The comparison suggests that a stochastic acceleration mechanism is operational and the heating is controlled by the transverse spatial scale of the Alfvenic waves.

  1. Islet Oxygen Consumption Rate (OCR) Dose Predicts Insulin Independence in Clinical Islet Autotransplantation

    PubMed Central

    Papas, Klearchos K.; Bellin, Melena D.; Sutherland, David E. R.; Suszynski, Thomas M.; Kitzmann, Jennifer P.; Avgoustiniatos, Efstathios S.; Gruessner, Angelika C.; Mueller, Kathryn R.; Beilman, Gregory J.; Balamurugan, Appakalai N.; Loganathan, Gopalakrishnan; Colton, Clark K.; Koulmanda, Maria; Weir, Gordon C.; Wilhelm, Josh J.; Qian, Dajun; Niland, Joyce C.; Hering, Bernhard J.

    2015-01-01

    Background Reliable in vitro islet quality assessment assays that can be performed routinely, prospectively, and are able to predict clinical transplant outcomes are needed. In this paper we present data on the utility of an assay based on cellular oxygen consumption rate (OCR) in predicting clinical islet autotransplant (IAT) insulin independence (II). IAT is an attractive model for evaluating characterization assays regarding their utility in predicting II due to an absence of confounding factors such as immune rejection and immunosuppressant toxicity. Methods Membrane integrity staining (FDA/PI), OCR normalized to DNA (OCR/DNA), islet equivalent (IE) and OCR (viable IE) normalized to recipient body weight (IE dose and OCR dose), and OCR/DNA normalized to islet size index (ISI) were used to characterize autoislet preparations (n = 35). Correlation between pre-IAT islet product characteristics and II was determined using receiver operating characteristic analysis. Results Preparations that resulted in II had significantly higher OCR dose and IE dose (p<0.001). These islet characterization methods were highly correlated with II at 6–12 months post-IAT (area-under-the-curve (AUC) = 0.94 for IE dose and 0.96 for OCR dose). FDA/PI (AUC = 0.49) and OCR/DNA (AUC = 0.58) did not correlate with II. OCR/DNA/ISI may have some utility in predicting outcome (AUC = 0.72). Conclusions Commonly used assays to determine whether a clinical islet preparation is of high quality prior to transplantation are greatly lacking in sensitivity and specificity. While IE dose is highly predictive, it does not take into account islet cell quality. OCR dose, which takes into consideration both islet cell quality and quantity, may enable a more accurate and prospective evaluation of clinical islet preparations. PMID:26258815

  2. In situ oxygen consumption rates of cells in V-79 multicellular spheroids during growth

    SciTech Connect

    Freyer, J.P.; Tustanoff, E.; Franko, A.J.; Sutherland, R.M.

    1984-01-01

    The rate of consumption of oxygen by V-79 cells in multicellular spheroids was measeured as a function of the spheroid diameter. In situ consumption was equal to that of exponentially growing cells for spheroids less than 200 ..mu..m in diameter. The rate of oxygen consumption decreased for cells in spheroids between 200 and 400 ..mu..m diameter to a value one-fourth the initial, then remained constant with further spheroid growth. Comparison of consumption rates for spheroid-derived cells before and after dissociation from the spheroid structure indicated that the spheroid microenvironment accounted for only 20% of the change in oxygen consumption rate. Cell-cell contact, cell packing, and cell volume were not critical parameters. Plateau-phase cells had a fivefold lower rate of oxygen consumption than exponential cells, and it is postulated that the spheroid quiescent cell population accounts for a large part of the intrinsic alteration in oxygen consumption of cells in spheroids. Some other mechanism must be involved in the regulation of cellular oxygen consumption in V-79 spheroids to account for the remainder of the reduction obvserved in this system.

  3. Daily changes in oxygen saturation and pulse rate associated with particulate air pollution and barometric pressure.

    PubMed

    Dockery, D W; Pope, C A; Kanner, R E; Martin Villegas, G; Schwartz, J

    1999-01-01

    Epidemiologic studies have linked fine particulate air pollution with increases in morbidity and mortality rates from cardiopulmonary complications. Although the underlying biologic mechanisms responsible for this increase remain largely unknown, potential pathways include transient declines in blood oxygenation and changes in pulse rate following exposures to particulate air pollution episodes. This study evaluated potential associations between daily measures of respirable particulate matter (PM) with pulse rate and oxygen saturation of the blood. Pulse rate and oxygen saturation (Spo2) using pulse oximetry were measured daily in 90 elderly subjects living near air pollution monitors during the winter of 1995-96 in Utah Valley. We also evaluated potential associations of oxygen saturation and pulse rate with barometric pressure. Small but statistically significant positive associations between day-to-day changes in Spo2 and barometric pressure were observed. Pulse rate was inversely associated with barometric pressure. Exposure to particulate pollution was not significantly associated with Spo2 except in male participants 80 years of age or older. Increased daily pulse rate, as well as the odds of having a pulse rate 5 or 10 beats per minute (bpm) above normal (normal is defined as the individual's mean pulse rate throughout the study period), were significantly associated with exposure to particulate pollution on the previous 1 to 5 days. The medical or biologic relevance of these increases in pulse rate following exposure to particulate air pollution requires further study. PMID:10192116

  4. Estimating streambed travel times and respiration rates based on temperature and oxygen consumption

    NASA Astrophysics Data System (ADS)

    Vieweg, M.; Fleckenstein, J. H.; Schmidt, C.

    2015-12-01

    Oxygen consumption is a common proxy for aerobic respiration and novel in situ measurement techniques with high spatial resolution enable an accurate determination of the oxygen distribution in the streambed. The oxygen concentration at a certain location in the streambed depends on the input concentration, the respiration rate, temperature, and the travel time of the infiltrating flowpath. While oxygen concentrations and temperature can directly be measured, respiration rate and travel time must be estimated from the data. We investigated the interplay of these factors using a 6 month long, 5-min resolution dataset collected in a 3rdorder gravel-bed stream. Our objective was twofold, to determine transient rates of hyporheic respiration and to estimate travel times in the streambed based solely on oxygen and temperature measurements. Our results show that temperature and travel time explains ~70% of the variation in oxygen concentration in the streambed. Independent travel times were obtained using natural variations in the electrical conductivity (EC) of the stream water as tracer (µ=4.1 h; σ=2.3 h). By combining these travel times with the oxygen consumption, we calculated a first order respiration rate (µ=9.7 d-1; σ=6.1 d-1). Variations in the calculated respiration rate are largely explained by variations in streambed temperature. An empirical relationship between our respiration rate and temperature agrees with the theoretical Boltzmann-Arrhenius equation. With this relationship, a temperature-based respiration rate can be estimated and used to re-estimate subsurface travel times. The resulting travel times distinctively resemble the EC-derived travel times (R20.47; Nash-Sutcliffe coefficient 0.32). Both calculations of travel time are correlated to stream water levels and increase during discharge events, enhancing the oxygen consumption for these periods. No other physical factors besides temperature were significantly correlated with the respiration

  5. Adjusting capitation rates using objective health measures and prior utilization

    PubMed Central

    Newhouse, Joseph P.; Manning, Willard G.; Keeler, Emmett B.; Sloss, Elizabeth M.

    1989-01-01

    Several analysts have proposed adding adjusters based on health status and prior utilization to the adjusted average per capita cost formula. The authors estimate how well such adjusters predict annual medical expenditures among non-elderly adults. Both measures substantially improve on the variables currently used. If only health measures are added, 20-30 percent of the predictable variance is explained; if only prior use is added, more than 40 percent is explained; if both are added, about 60 percent is explained. The results support including some measure of use in the formula until better health measures are developed. PMID:10313096

  6. Glucose utilization rates regulate intake levels of artificial sweeteners

    PubMed Central

    Tellez, Luis A; Ren, Xueying; Han, Wenfei; Medina, Sara; Ferreira, Jozélia G; Yeckel, Catherine W; de Araujo, Ivan E

    2013-01-01

    It is well established that animals including humans attribute greater reinforcing value to glucose-containing sugars compared to their non-caloric counterparts, generally termed ‘artificial sweeteners’. However, much remains to be determined regarding the physiological signals and brain systems mediating the attribution of greater reinforcing value to sweet solutions that contain glucose. Here we show that disruption of glucose utilization in mice produces an enduring inhibitory effect on artificial sweetener intake, an effect that did not depend on sweetness perception or aversion. Indeed, such an effect was not observed in mice presented with a less palatable, yet caloric, glucose solution. Consistently, hungry mice shifted their preferences away from artificial sweeteners and in favour of glucose after experiencing glucose in a hungry state. Glucose intake was found to produce significantly greater levels of dopamine efflux compared to artificial sweetener in dorsal striatum, whereas disrupting glucose oxidation suppressed dorsal striatum dopamine efflux. Conversely, inhibiting striatal dopamine receptor signalling during glucose intake in sweet-naïve animals resulted in reduced, artificial sweetener-like intake of glucose during subsequent gluco-deprivation. Our results demonstrate that glucose oxidation controls intake levels of sweet tastants by modulating extracellular dopamine levels in dorsal striatum, and suggest that glucose utilization is one critical physiological signal involved in the control of goal-directed sweetener intake. PMID:24060992

  7. Glucose utilization rates regulate intake levels of artificial sweeteners.

    PubMed

    Tellez, Luis A; Ren, Xueying; Han, Wenfei; Medina, Sara; Ferreira, Jozélia G; Yeckel, Catherine W; de Araujo, Ivan E

    2013-11-15

    It is well established that animals including humans attribute greater reinforcing value to glucose-containing sugars compared to their non-caloric counterparts, generally termed 'artificial sweeteners'. However, much remains to be determined regarding the physiological signals and brain systems mediating the attribution of greater reinforcing value to sweet solutions that contain glucose. Here we show that disruption of glucose utilization in mice produces an enduring inhibitory effect on artificial sweetener intake, an effect that did not depend on sweetness perception or aversion. Indeed, such an effect was not observed in mice presented with a less palatable, yet caloric, glucose solution. Consistently, hungry mice shifted their preferences away from artificial sweeteners and in favour of glucose after experiencing glucose in a hungry state. Glucose intake was found to produce significantly greater levels of dopamine efflux compared to artificial sweetener in dorsal striatum, whereas disrupting glucose oxidation suppressed dorsal striatum dopamine efflux. Conversely, inhibiting striatal dopamine receptor signalling during glucose intake in sweet-naïve animals resulted in reduced, artificial sweetener-like intake of glucose during subsequent gluco-deprivation. Our results demonstrate that glucose oxidation controls intake levels of sweet tastants by modulating extracellular dopamine levels in dorsal striatum, and suggest that glucose utilization is one critical physiological signal involved in the control of goal-directed sweetener intake. PMID:24060992

  8. Plant genotypic diversity reduces the rate of consumer resource utilization

    PubMed Central

    McArt, Scott H.; Thaler, Jennifer S.

    2013-01-01

    While plant species diversity can reduce herbivore densities and herbivory, little is known regarding how plant genotypic diversity alters resource utilization by herbivores. Here, we show that an invasive folivore—the Japanese beetle (Popillia japonica)—increases 28 per cent in abundance, but consumes 24 per cent less foliage in genotypic polycultures compared with monocultures of the common evening primrose (Oenothera biennis). We found strong complementarity for reduced herbivore damage among plant genotypes growing in polycultures and a weak dominance effect of particularly resistant genotypes. Sequential feeding by P. japonica on different genotypes from polycultures resulted in reduced consumption compared with feeding on different plants of the same genotype from monocultures. Thus, diet mixing among plant genotypes reduced herbivore consumption efficiency. Despite positive complementarity driving an increase in fruit production in polycultures, we observed a trade-off between complementarity for increased plant productivity and resistance to herbivory, suggesting costs in the complementary use of resources by plant genotypes may manifest across trophic levels. These results elucidate mechanisms for how plant genotypic diversity simultaneously alters resource utilization by both producers and consumers, and show that population genotypic diversity can increase the resistance of a native plant to an invasive herbivore. PMID:23658201

  9. Is the surface oxygen exchange rate linked to bulk ion diffusivity in mixed conducting Ruddlesden–Popper phases?

    SciTech Connect

    Tomkiewicz, Alex C.; Tamimi, Mazin A.; Huq, Ashfia; McIntosh, Steven

    2015-03-02

    There is a possible link between oxygen surface exchange rate and bulk oxygen anion diffusivity in mixed ionic and electronic conducting oxides; it is a topic of great interest and debate. While a large body of experimental evidence and theoretical analyses support a link, observed differences between bulk and surface composition of these materials are hard to reconcile with this observation. This is further compounded by potential problems with simultaneous measurement of both parameters. Here we utilize separate techniques, in situ neutron diffraction and pulsed isotopic surface exchange, to examine bulk ion mobility and surface oxygen exchange rates of three Ruddlesden-Popper phases, general form An-1A2'BnO3n+1, An-1A2'BnX3n+1; LaSrCo0.5Fe0.5O4-δ (n = 1), La0.3Sr2.7CoFeO7-δ (n = 2) and LaSr3Co1.5Fe1.5O10-δ (n = 3). These measurements are complemented by surface composition determination via high sensitivity-low energy ion scattering. We observe a correlation between bulk ion mobility and surface exchange rate between materials. The surface exchange rates vary by more than one order of magnitude with high anion mobility in the bulk of an oxygen vacancy-rich n = 2 Ruddlesden-Popper material correlating with rapid oxygen exchange. Furthermore this is in contrast with the similar surface exchange rates which we may expect due to similar surface compositions across all three samples. This paper conclude that experimental limitations lead to inherent convolution of surface and bulk rates, and that surface exchange steps are not likely to be rate limiting in oxygen incorporation.

  10. Quantifying the density and utilization of active sites in non-precious metal oxygen electroreduction catalysts.

    PubMed

    Sahraie, Nastaran Ranjbar; Kramm, Ulrike I; Steinberg, Julian; Zhang, Yuanjian; Thomas, Arne; Reier, Tobias; Paraknowitsch, Jens-Peter; Strasser, Peter

    2015-01-01

    Carbon materials doped with transition metal and nitrogen are highly active, non-precious metal catalysts for the electrochemical conversion of molecular oxygen in fuel cells, metal air batteries, and electrolytic processes. However, accurate measurement of their intrinsic turn-over frequency and active-site density based on metal centres in bulk and surface has remained difficult to date, which has hampered a more rational catalyst design. Here we report a successful quantification of bulk and surface-based active-site density and associated turn-over frequency values of mono- and bimetallic Fe/N-doped carbons using a combination of chemisorption, desorption and (57)Fe Mössbauer spectroscopy techniques. Our general approach yields an experimental descriptor for the intrinsic activity and the active-site utilization, aiding in the catalyst development process and enabling a previously unachieved level of understanding of reactivity trends owing to a deconvolution of site density and intrinsic activity. PMID:26486465

  11. Quantifying the density and utilization of active sites in non-precious metal oxygen electroreduction catalysts

    NASA Astrophysics Data System (ADS)

    Sahraie, Nastaran Ranjbar; Kramm, Ulrike I.; Steinberg, Julian; Zhang, Yuanjian; Thomas, Arne; Reier, Tobias; Paraknowitsch, Jens-Peter; Strasser, Peter

    2015-10-01

    Carbon materials doped with transition metal and nitrogen are highly active, non-precious metal catalysts for the electrochemical conversion of molecular oxygen in fuel cells, metal air batteries, and electrolytic processes. However, accurate measurement of their intrinsic turn-over frequency and active-site density based on metal centres in bulk and surface has remained difficult to date, which has hampered a more rational catalyst design. Here we report a successful quantification of bulk and surface-based active-site density and associated turn-over frequency values of mono- and bimetallic Fe/N-doped carbons using a combination of chemisorption, desorption and 57Fe Mössbauer spectroscopy techniques. Our general approach yields an experimental descriptor for the intrinsic activity and the active-site utilization, aiding in the catalyst development process and enabling a previously unachieved level of understanding of reactivity trends owing to a deconvolution of site density and intrinsic activity.

  12. Quantifying the density and utilization of active sites in non-precious metal oxygen electroreduction catalysts

    PubMed Central

    Sahraie, Nastaran Ranjbar; Kramm, Ulrike I.; Steinberg, Julian; Zhang, Yuanjian; Thomas, Arne; Reier, Tobias; Paraknowitsch, Jens-Peter; Strasser, Peter

    2015-01-01

    Carbon materials doped with transition metal and nitrogen are highly active, non-precious metal catalysts for the electrochemical conversion of molecular oxygen in fuel cells, metal air batteries, and electrolytic processes. However, accurate measurement of their intrinsic turn-over frequency and active-site density based on metal centres in bulk and surface has remained difficult to date, which has hampered a more rational catalyst design. Here we report a successful quantification of bulk and surface-based active-site density and associated turn-over frequency values of mono- and bimetallic Fe/N-doped carbons using a combination of chemisorption, desorption and 57Fe Mössbauer spectroscopy techniques. Our general approach yields an experimental descriptor for the intrinsic activity and the active-site utilization, aiding in the catalyst development process and enabling a previously unachieved level of understanding of reactivity trends owing to a deconvolution of site density and intrinsic activity. PMID:26486465

  13. Temperature-dependent reaction-rate expression for oxygen recombination at Shuttle entry conditions

    NASA Technical Reports Server (NTRS)

    Zoby, E. V.; Simmonds, A. L.; Gupta, R. N.

    1984-01-01

    A temperature-dependent oxygen surface reaction-rate coefficient has been determined from experimental STS-2 heating and wall temperature data at altitudes of 77.91 km, 74.98 km, and 71.29 km. The coefficient is presented in an Arrhenius form and is shown to be less temperature dependent than previous results. Finite-rate viscous-shock-layer heating rates based on this present expression have been compared with predicted heating rates using the previous rate coefficients and with experimental heating data obtained over an extensive range of STS-2 and STS-3 entry conditions. A substantial improvement is obtained in comparison of experimental data and predicted heating rates using the present oxygen reaction-rate expression.

  14. System for measuring oxygen consumption rates of mammalian cells in static culture under hypoxic conditions.

    PubMed

    Kagawa, Yuki; Miyahara, Hirotaka; Ota, Yuri; Tsuneda, Satoshi

    2016-01-01

    Estimating the oxygen consumption rates (OCRs) of mammalian cells in hypoxic environments is essential for designing and developing a three-dimensional (3-D) cell culture system. However, OCR measurements under hypoxic conditions are infrequently reported in the literature. Here, we developed a system for measuring OCRs at low oxygen levels. The system injects nitrogen gas into the environment and measures the oxygen concentration by an optical oxygen microsensor that consumes no oxygen. The developed system was applied to HepG2 cells in static culture. Specifically, we measured the spatial profiles of the local dissolved oxygen concentration in the medium, then estimated the OCRs of the cells. The OCRs, and also the pericellular oxygen concentrations, decreased nonlinearly as the oxygen partial pressure in the environment decreased from 19% to 1%. The OCRs also depended on the culture period and the matrix used for coating the dish surface. Using this system, we can precisely estimate the OCRs of various cell types under environments that mimic 3-D culture conditions, contributing crucial data for an efficient 3-D culture system design. PMID:26558344

  15. Method for enhancing microbial utilization rates of gases using perfluorocarbons

    DOEpatents

    Turick, C.E.

    1997-06-10

    A method of enhancing the bacterial reduction of industrial gases using perfluorocarbons (PFCs) is disclosed. Because perfluorocarbons (PFCs) allow for a much greater solubility of gases than water does, PFCs have the potential to deliver gases in higher concentrations to microorganisms when used as an additive to microbial growth media thereby increasing the rate of the industrial gas conversion to economically viable chemicals and gases. 3 figs.

  16. Method for enhancing microbial utilization rates of gases using perfluorocarbons

    DOEpatents

    Turick, Charles E.

    1997-01-01

    A method of enhancing the bacterial reduction of industrial gases using perfluorocarbons (PFCs) is disclosed. Because perfluorocarbons (PFCs) allow for a much greater solubility of gases than water does, PFCs have the potential to deliver gases in higher concentrations to microorganisms when used as an additive to microbial growth media thereby increasing the rate of the industrial gas conversion to economically viable chemicals and gases.

  17. Stock price change rate prediction by utilizing social network activities.

    PubMed

    Deng, Shangkun; Mitsubuchi, Takashi; Sakurai, Akito

    2014-01-01

    Predicting stock price change rates for providing valuable information to investors is a challenging task. Individual participants may express their opinions in social network service (SNS) before or after their transactions in the market; we hypothesize that stock price change rate is better predicted by a function of social network service activities and technical indicators than by a function of just stock market activities. The hypothesis is tested by accuracy of predictions as well as performance of simulated trading because success or failure of prediction is better measured by profits or losses the investors gain or suffer. In this paper, we propose a hybrid model that combines multiple kernel learning (MKL) and genetic algorithm (GA). MKL is adopted to optimize the stock price change rate prediction models that are expressed in a multiple kernel linear function of different types of features extracted from different sources. GA is used to optimize the trading rules used in the simulated trading by fusing the return predictions and values of three well-known overbought and oversold technical indicators. Accumulated return and Sharpe ratio were used to test the goodness of performance of the simulated trading. Experimental results show that our proposed model performed better than other models including ones using state of the art techniques. PMID:24790586

  18. Stock Price Change Rate Prediction by Utilizing Social Network Activities

    PubMed Central

    Mitsubuchi, Takashi; Sakurai, Akito

    2014-01-01

    Predicting stock price change rates for providing valuable information to investors is a challenging task. Individual participants may express their opinions in social network service (SNS) before or after their transactions in the market; we hypothesize that stock price change rate is better predicted by a function of social network service activities and technical indicators than by a function of just stock market activities. The hypothesis is tested by accuracy of predictions as well as performance of simulated trading because success or failure of prediction is better measured by profits or losses the investors gain or suffer. In this paper, we propose a hybrid model that combines multiple kernel learning (MKL) and genetic algorithm (GA). MKL is adopted to optimize the stock price change rate prediction models that are expressed in a multiple kernel linear function of different types of features extracted from different sources. GA is used to optimize the trading rules used in the simulated trading by fusing the return predictions and values of three well-known overbought and oversold technical indicators. Accumulated return and Sharpe ratio were used to test the goodness of performance of the simulated trading. Experimental results show that our proposed model performed better than other models including ones using state of the art techniques. PMID:24790586

  19. From Oxygen Generation to Metals Production: In Situ Resource Utilization by Molten Oxide Electrolysis

    NASA Technical Reports Server (NTRS)

    Khetpal, Deepak; Ducret, Andrew C.; Sadoway, Donald R.

    2003-01-01

    For the exploration of other bodies in the solar system, electrochemical processing is arguably the most versatile technology for conversion of local resources into usable commodities: by electrolysis one can, in principle, produce (1) breathable oxygen, (2) silicon for the fabrication of solar cells, (3) various reactive metals for use as electrodes in advanced storage batteries, and (4) structural metals such as steel and aluminum. Even so, to date there has been no sustained effort to develop such processes, in part due to the inadequacy of the database. The objective here is to identify chemistries capable of sustaining molten oxide electrolysis in the cited applications and to examine the behavior of laboratory-scale cells designed to generate oxygen and to produce metal. The basic research includes the study of the underlying high-temperature physical chemistry of oxide melts representative of lunar regolith and of Martian soil. To move beyond empirical approaches to process development, the thermodynamic and transport properties of oxide melts are being studied to help set the limits of composition and temperature for the processing trials conducted in laboratory-scale electrolysis cells. The goal of this investigation is to deliver a working prototype cell that can use lunar regolith and Martian soil to produce breathable oxygen along with metal by-product. Additionally, the process can be generalized to permit adaptation to accommodate different feedstock chemistries, such as those that will be encountered on other bodies in the solar system. The expected results of this research include: (1) the identification of appropriate electrolyte chemistries; (2) the selection of candidate anode and cathode materials compatible with electrolytes named above; and (3) performance data from a laboratory-scale cell producing oxygen and metal. On the strength of these results it should be possible to assess the technical viability of molten oxide electrolysis for in

  20. Efficiency of Photosynthesis in a Chl d-Utilizing Cyanobacterium is Comparable to or Higher than that in Chl a-Utilizing Oxygenic Species

    NASA Technical Reports Server (NTRS)

    Mielke, S. P.; Kiang, N. Y.; Blankenship, R. E.; Gunner, M. R.; Mauzerall, D.

    2011-01-01

    The cyanobacterium Acaryochloris marina uses chlorophyll d to carry out oxygenic photosynthesis in environments depleted in visible and enhanced in lower-energy, far-red light. However, the extent to which low photon energies limit the efficiency of oxygenic photochemistry in A. marina is not known. Here, we report the first direct measurements of the energy-storage efficiency of the photosynthetic light reactions in A. marina whole cells,and find it is comparable to or higher than that in typical, chlorophyll a-utilizing oxygenic species. This finding indicates that oxygenic photosynthesis is not fundamentally limited at the photon energies employed by A. marina, and therefore is potentially viable in even longer-wavelength light environments.

  1. An analytical prediction of pilot ratings utilizing human pilot model

    NASA Technical Reports Server (NTRS)

    Tanaka, K.; Washizu, K.

    1982-01-01

    In order to analytically predict pilot ratings, an evaluation method of a manual control system which consists of an aircraft and a human pilot, is proposed and examined. The method is constructed upon the assumptions that the control mission determines the critical frequency the pilot should bring to his focus, and that the degree of closed-loop stability and the human compensation necessary to attain the stability determine the human subjective evaluation of the system. As a result, a simple evaluation chart is introduced. The chart enables prediction of the subjective evaluation, if the controlled element dynamics and the mission are given. The chart is in good accord with almost all of the existing results of pilot ratings. This method has the following advantages: (1) simplicity, in a sense that the method needs to evaluate only two typical controlled element parameters, namely, the gain slope and the phase at the critical control frequency; (2) applicability to unstable controlled elements; (3) predictability of controllability limits of manual control; (4) possibility of estimating human compensatory dynamics.

  2. A comparison of the tissue oxygenation achieved using different oxygen delivery devices and flow rates.

    PubMed

    2016-03-01

    Consistent with the Committee on Publication Ethics guidelines, we the above authors are initiating a partial retraction of our paper: Blake DF, Naidoo P, Brown LH, Young DA, Lippmann J: A comparison of the tissue oxygenation achieved using different oxygen delivery devices and flow rates. Diving Hyperb Med. 2015;45:79-83. We wish to make the following statement: "The authors voluntarily retract aspects of this article after discovering a critical error associated with the instrumentation used in the study, namely the fitting of incorrect sensor membranes on the electrodes of the transcutaneous oximetry device used in the study. This resulted in transcutaneous oxygen tension (PtcO₂) measurements that were consistently lower than those that would be recorded with the correct electrode membranes in place. This measurement error was consistent across all arms of the study. This non-differential information error would have created a bias toward the null hypothesis. Therefore, whilst the absolute values for the data were incorrect, the direction and implications of the significant associations reported in this study are unchanged." PMID:27044467

  3. Effect of Oxygen on Glucose Metabolism: Utilization of Lactate in Staphylococcus Aureus as Revealed by In Vivo NMR Studies

    PubMed Central

    Gaspar, Paula; Pinho, Mariana G.; Neves, Ana Rute

    2013-01-01

    The ability to successfully adapt to changing host conditions is crucial for full virulence of bacterial pathogens. Staphylococcus aureus has to cope with fluctuating oxygen concentrations during the course of infection. Hence, we studied the effect of oxygen on glucose metabolism in non-growing S. aureus COL-S cells by in vivo 13C-NMR. Glucose catabolism was probed at different oxygen concentrations in suspensions of cells grown aerobically (direct effects on metabolism) or anaerobically (transcriptional adjustment to oxygen deprivation). In aerobically-grown cells, the rate of glucose consumption diminished progressively with decreasing oxygen concentrations. Additionally, oxygen deprivation resulted in biphasic glucose consumption, with the second phase presenting a higher rate. The fructose-1,6-bisphosphate pool peaked while glucose was still abundant, but the transient maximum varied with the oxygen concentration. As oxygen became limiting mannitol/mannitol-1-phosphate were detected as products of glucose catabolism. Under anoxic conditions, accumulation of mannitol-1-phosphate ceased with the switch to higher glucose consumption rates, which implies the activation of a more efficient means by which NAD+ can be regenerated. The distribution of end-products deriving from glucose catabolism was dramatically affected by oxygen: acetate increased and lactate decreased with the oxygen concentration; ethanol was formed only anaerobically. Moreover, oxygen promoted the energetically favourable conversion of lactate into acetate, which was particularly noticeable under fully oxygenated conditions. Interestingly, under aerobiosis growing S. aureus cells also converted lactate to acetate, used simultaneously glucose and lactate as substrates for growth, and grew considerably well on lactate-medium. We propose that the efficient lactate catabolism may endow S. aureus with a metabolic advantage in its ecological niche. PMID:23472168

  4. Modelling Oxygen Dynamics in an Intermittently Stratified Estuary: Estimation of Process Rates Using Field Data

    NASA Astrophysics Data System (ADS)

    Borsuk, M. E.; Stow, C. A.; Luettich, R. A.; Paerl, H. W.; Pinckney, J. L.

    2001-01-01

    The relationship between bottom water dissolved oxygen concentration, vertical stratification, and temperature was investigated for the Neuse River estuary, North Carolina, a shallow, intermittently-mixed estuary using approximately 10 years of weekly/biweekly, mid-channel data. A generalized additive model (GAM) was used to initially explore the major relationships among observed variables. The results of this statistical model guided the specification of a process-based model of oxygen dynamics that is consistent with theory yet simple enough to be parameterized using available field data. The nonlinear optimization procedure employed allows for the direct estimation of microbial oxygen consumption and physical reoxygenation rates, including the effects of temperature and vertical stratification. These estimated rates may better represent aggregate system behaviour than closed chamber measurements made in the laboratory and in situ. The resulting model describes 79% of the variation in dissolved oxygen concentration and is robust when compared across separate locations and time periods. Model predictions suggest that the spatial extent and duration of hypoxia in the bottom waters of the Neuse are controlled by the balance between the net oxygen depletion rate and the frequency of vertical mixing events. During cool months, oxygen consumption rates remain low enough to keep oxygen concentration well above levels of concern even under extended periods of stratification. A concentration below 4 mg l -1is only expected under extended periods without vertical mixing when bottom water temperature exceeds 15 °C, while a concentration below 2 mg l -1is only expected when water temperature exceeds 20 °C. To incorporate the effects of parameter uncertainty, model error, and natural variability on model prediction, we used Monte Carlo simulation to generate distributions for the predicted number of days of hypoxia during the summer season. The expected number of days with

  5. New oxygen radical source using selective sputtering of oxygen atoms for high rate deposition of TiO{sub 2} films

    SciTech Connect

    Yasuda, Yoji; Lei, Hao; Hoshi, Yoichi

    2012-11-15

    We have developed a new oxygen radical source based on the reactive sputtering phenomena of a titanium target for high rate deposition of TiO{sub 2} films. In this oxygen radical source, oxygen radicals are mainly produced by two mechanisms: selective sputter-emission of oxygen atoms from the target surface covered with a titanium oxide layer, and production of high-density oxygen plasma in the space near the magnetron-sputtering cathode. Compared with molecular oxygen ions, the amount of atomic oxygen radicals increased significantly with an increase in discharge current so that atomic oxygen radicals were mainly produced by this radical source. It should be noted that oxygen atoms were selectively sputtered from the target surface, and titanium atoms sputter-emitted from the target cathode were negligibly small. The amount of oxygen radicals supplied from this radical source increased linearly with increasing discharge current, and oxygen radicals of 1 Multiplication-Sign 10{sup 15} atoms/s/cm{sup 2} were supplied to the substrate surface at a discharge current of 1.2 A. We conclude that our newly developed oxygen radical source can be a good tool to achieve high rate deposition and to control the structure of TiO{sub 2} films for many industrial design applications.

  6. High-rate supercapacitor utilizing hydrous ruthenium dioxide nanotubes

    NASA Astrophysics Data System (ADS)

    Wu, Xu; Xiong, Wei; Chen, Yangyang; Lan, Danni; Pu, Xuli; Zeng, Yan; Gao, Hairui; Chen, Jisheng; Tong, Hua; Zhu, Zhihong

    2015-10-01

    Three-dimensional criss-crossed hydrous ruthenium dioxide (RuO2) nanotubes directly on a Ti substrate without any binder are successfully synthesized for the first time via a facile template method at a low temperature of 90 °C. A cobalt-hydroxide-carbonate nanowire array is used as the template and can be completely dissolved away during the formation process of the tubular structure. The synthetic strategy is much more cost-effective and facile than other physical/chemical methods. The obtained material possesses proper crystallinity and water content together with a distinctive structure, resulting in superior electron and ion transmission performance. When the binder-free electrode is used in a supercapacitor, it exhibits a remarkable high-rate performance with a specific capacitance of 745 F g-1 at a high current density of 32 A g-1. This represents a retention of 88.7% compared to the value of 840 F g-1 at 2 A g-1.

  7. Polymer etching in the oxygen afterglow - Increased etch rates with increased reactor loading

    NASA Technical Reports Server (NTRS)

    Lerner, N. R.; Wydeven, T.

    1989-01-01

    Reactor loading has an effect on the etch rate (rate of decrease of film thickness) of films of polyvinylfluoride (Tedlar) and polyethylene exposed in the afterglow of an RF discharge in oxygen. The etch rate is found to increase with the total surface area of the polymer exposed in the reactor. The etch rates of polypyromellitimide (Kapton H) and polystyrene under these conditions are very low. However, the etch rate of these polymers is greatly enhanced by adding either Tedlar or polyethylene to the reactor. A kinetic model is proposed based on the premise that the oxygen atoms produced by the RF discharge react with Tedlar or polyethylene to produce a much more reactive species, which dominates the etching of the polymers studied.

  8. The influence of thermal annealing on oxygen uptake and combustion rates of a bituminous coal char

    SciTech Connect

    Osvalda Senneca; Piero Salatino; Daniela Menghini

    2007-07-01

    The effect of thermal annealing on the combustion reactivity of a bituminous coal char has been investigated with a focus on the role of the formation of surface oxides by oxygen chemisorption. The combined use of thermogravimetric analysis and of analysis of the off-gas during isothermal combustion of char samples enabled the determination of the rate and extent of oxygen uptake along burn-off. Combustion was carried out at temperatures between 350 and 510{sup o}C. Char samples were prepared by controlled isothermal heat treatment of coal for different times (in the range between 1 s and 30 min) at different temperatures (in the range 900-2000{sup o}C). Results indicate that oxygen uptake is extensive along burn-off of chars prepared under mild heat treatment conditions. The maximum oxygen uptake is barely affected by the combustion temperature within the range of combustion conditions investigated. The severity of heat treatment has a pronounced effect on char combustion rate as well as on the extent and rate at which surface oxides are built up by oxygen chemisorption. Chars prepared under severe heat treatment conditions show negligible oxygen uptake and strongly reduced combustion rates. Altogether it appears that a close correlation can be established between the extent and the accessibility of active sites on the carbon surface and the combustion rate. Despite the investigation has been carried out at temperatures well below those of practical interest, results provide useful insight into the relationship existing between thermal annealing, formation of surface oxide and combustion reactivity which is relevant to the proper formulation of detailed kinetic models of char combustion. 31 refs., 6 figs., 1 tab.

  9. Glucose consumption rate critically depends on redox state in Corynebacterium glutamicum under oxygen deprivation.

    PubMed

    Tsuge, Yota; Uematsu, Kimio; Yamamoto, Shogo; Suda, Masako; Yukawa, Hideaki; Inui, Masayuki

    2015-07-01

    Rapid sugar consumption is important for the microbial production of chemicals and fuels. Here, we show that overexpression of the NADH dehydrogenase gene (ndh) increased glucose consumption rate in Corynebacterium glutamicum under oxygen-deprived conditions through investigating the relationship between the glucose consumption rate and intracellular NADH/NAD(+) ratio in various mutant strains. The NADH/NAD(+) ratio was strongly repressed under oxygen deprivation when glucose consumption was accelerated by the addition of pyruvate or sodium hydrogen carbonate. Overexpression of the ndh gene in the wild-type strain under oxygen deprivation decreased the NADH/NAD(+) ratio from 0.32 to 0.13, whereas the glucose consumption rate increased by 27%. Similarly, in phosphoenolpyruvate carboxylase gene (ppc)- or malate dehydrogenase gene (mdh)-deficient strains, overexpression of the ndh gene decreased the NADH/NAD(+) ratio from 1.66 to 0.37 and 2.20 to 0.57, respectively, whereas the glucose consumption rate increased by 57 and 330%, respectively. However, in a lactate dehydrogenase gene (L-ldhA)-deficient strain, although the NADH/NAD(+) ratio decreased from 5.62 to 1.13, the glucose consumption rate was not markedly altered. In a tailored D-lactate-producing strain, which lacked ppc and L-ldhA genes, but expressed D-ldhA from Lactobacillus delbrueckii, overexpression of the ndh gene decreased the NADH/NAD(+) ratio from 1.77 to 0.56, and increased the glucose consumption rate by 50%. Overall, the glucose consumption rate was found to be inversely proportional to the NADH/NAD(+) ratio in C. glutamicum cultured under oxygen deprivation. These findings could provide an option to increase the productivity of chemicals and fuels under oxygen deprivation. PMID:25808520

  10. Combined photoacoustic microscopy and optical coherence tomography can measure metabolic rate of oxygen

    PubMed Central

    Liu, Tan; Wei, Qing; Wang, Jing; Jiao, Shuliang; Zhang, Hao F.

    2011-01-01

    We proposed to measure the metabolic rate of oxygen (MRO2) in small animals in vivo using a multimodal imaging system that combines laser-scanning optical-resolution photoacoustic microscopy (LSOR-PAM) and spectral-domain optical coherence tomography (SD-OCT). We first tested the capability of the multimodal system to measure flow rate in a phantom made of two capillary tubes of different diameters. We then demonstrated the capability of measuring MRO2 by imaging two parallel vessels selected from the ear of a Swiss Webster mouse. The hemoglobin oxygen saturation (sO2) and the vessel diameter were measured by the LSOR-PAM and the blood flow velocity was measured by the SD-OCT, from which blood flow rate and MRO2 were further calculated. The measured blood flow rates in the two vessels agreed with each other. PMID:21559147

  11. PACKAGE FILM OXYGEN TRANSMISSION RATE AFFECTS POSTHARVEST BIOLOGY AND QUALITY OF FRESH-CUT CILANTRO LEAVES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Experiments were conducted to develop a modified atmosphere packaging system for fresh-cut cilantro (Coriandrum sativum L.) leaves, and to determine the effect of package film oxygen transmission rate (OTR) on postharvest physiology and quality of the products. Package film OTR significantly (P<0.0...

  12. Detection of the oxygen consumption rate of migrating zebrafish by electrochemical equalization systems.

    PubMed

    Yasukawa, Tomoyuki; Koide, Masahiro; Tatarazako, Norihisa; Abe, Ryoko; Shiku, Hitoshi; Mizutani, Fumio; Matsue, Tomokazu

    2014-01-01

    A novel measurement system to determine oxygen consumption rates via respiration in migrating Zebrafish (Danio rerio) has been developed. A signal equalization system was adapted to detect oxygen in a chamber with one fish, because typical electrochemical techniques cannot measure respiration activities for migrating organisms. A closed chamber was fabricated using a pipet tip attached to a Pt electrode, and a columnar Vycor glass tip was used as the salt bridge. Pt electrode, which was attached to the chamber with one zebrafish, and Ag electrode were immersed in 10 mM potassium iodide (KI), and both the electrodes were connected externally to form a galvanic cell. Pt and Ag electrodes act as the cathode and anode to reduce oxygen and oxidize silver, respectively, allowing the deposition of insoluble silver iodide (AgI). The AgI acts as the signal source accumulated on the Ag electrode by conversion of oxygen. The amount of AgI deposited on the Ag electrode was determined by cathodic stripping voltammetry. The presence of zebrafish or its embryo led to a decrease in the stripping currents generated by a 10 min conversion of oxygen to AgI. The conversion of oxygen to AgI is disturbed by the migration of the zebrafish and allows the detection of different equalized signals corresponding to respiration activity. The oxygen consumption rates of the zebrafish and its embryo were estimated and determined to be ∼4.1 and 2.4 pmol·s(-1), respectively. The deposited AgI almost completely disappeared with a single stripping process. The signal equalization system provides a method to determine the respiration activities for migrating zebrafish and could be used to estimate environmental risk and for effective drug screening. PMID:24328209

  13. The Utility of Thin Slice Ratings for Predicting Language Growth in Children with Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Walton, Katherine M.; Ingersoll, Brooke R.

    2016-01-01

    Literature on "Thin Slice" ratings indicates that a number of personality characteristics and behaviors can be accurately predicted by ratings of very short segments (<5?min) of behavior. This study examined the utility of Thin Slice ratings of young children with autism spectrum disorder for predicting developmental skills and…

  14. Rate of Biochemical oxygen demand during formation of hypoxia in Amur Bay, Sea of Japan

    NASA Astrophysics Data System (ADS)

    Tishchenko, P. P.; Tishchenko, P. Ya.; Zvalinskii, V. I.; Semkin, P. Yu.

    2014-12-01

    In May 2011, a Water Quality Monitor (WQM) hydrological station was maintained in the hypoxia area of Amur Bay one meter above the bottom, at the depth of 19 m. The temperature, electric conductivity, pressure, and content of dissolved oxygen were registered every four hours for more than three months. On the basis of these data, it was found that the period of hypoxia at the observation point lasted 93 days and a model of calculation of the rate of biochemical oxygen demand and the velocity of ventilation of the bottom waters is suggested.

  15. The rate constant for the reaction of oxygen /3P/ atoms with dichlorine monoxide

    NASA Technical Reports Server (NTRS)

    Miziolek, A. W.; Molina, M. J.

    1978-01-01

    A fast flow discharge apparatus was used to measure the rate constant for the reaction of ground state oxygen atoms with dichlorine monoxide in the temperature range 236-295 K. The air afterflow technique (NO2 chemiluminescence) was used for detection of oxygen atoms. The Arrhenius expression for the rate constant was found to be 2.7 plus or minus 0.3 times 10 to the -11th power exp(-560 plus or minus 80/T) cu cm per molecule per sec. At 295 K the rate constant is 4.1 plus or minus 0.5 times 10 to the -12th power cu cm per molecule per sec.

  16. The effects of strenuous exercises on resting heart rate, blood pressure, and maximal oxygen uptake.

    PubMed

    Oh, Deuk-Ja; Hong, Hyeon-Ok; Lee, Bo-Ae

    2016-02-01

    The purpose of this study is to investigate the effects of strenuous exercises on resting heart rate, blood pressure, and maximal oxygen uptake. To achieve the purpose of the study, a total of 30 subjects were selected, including 15 people who performed continued regular exercises and 15 people as the control group. With regard to data processing, the IBM SPSS Statistics ver. 21.0 was used to calculate the mean and standard deviation. The difference of mean change between groups was verified through an independent t-test. As a result, there were significant differences in resting heart rate, maximal heart rate, maximal systolic blood pressure, and maximal oxygen uptake. However, the maximal systolic blood pressure was found to be an exercise-induced high blood pressure. Thus, it is thought that a risk diagnosis for it through a regular exercise stress test is necessary. PMID:26933659

  17. The effects of strenuous exercises on resting heart rate, blood pressure, and maximal oxygen uptake

    PubMed Central

    Oh, Deuk-Ja; Hong, Hyeon-Ok; Lee, Bo-Ae

    2016-01-01

    The purpose of this study is to investigate the effects of strenuous exercises on resting heart rate, blood pressure, and maximal oxygen uptake. To achieve the purpose of the study, a total of 30 subjects were selected, including 15 people who performed continued regular exercises and 15 people as the control group. With regard to data processing, the IBM SPSS Statistics ver. 21.0 was used to calculate the mean and standard deviation. The difference of mean change between groups was verified through an independent t-test. As a result, there were significant differences in resting heart rate, maximal heart rate, maximal systolic blood pressure, and maximal oxygen uptake. However, the maximal systolic blood pressure was found to be an exercise-induced high blood pressure. Thus, it is thought that a risk diagnosis for it through a regular exercise stress test is necessary. PMID:26933659

  18. Report on Child Care Services in Ramsey County: Fees Charged and Rates of Utilization.

    ERIC Educational Resources Information Center

    Ramsey County Child Care Council, Inc., St. Paul, Minn.

    This report describes the second annual survey of utilization of child care services (day care homes and day care centers) in Ramsey County, Minnesota. Information about fees charged is included. Data from day care homes and centers were collected by mail or telephone. The rate of utilization of child care services was determined by county, county…

  19. The Utility of Clinicians Ratings of Anxiety Using the Pediatric Anxiety Rating Scale (PARS)

    ERIC Educational Resources Information Center

    Ginsburg, Golda S.; Keeton, Courtney P.; Drazdowski, Tess K.; Riddle, Mark A.

    2011-01-01

    Clinician ratings of anxiety hold the promise of clarifying discrepancies often found between child and parent reports of anxiety. The Pediatric Anxiety Rating Scale (PARS) is a clinician-administered instrument that assesses the frequency, severity, and impairment of common pediatric anxiety disorders and has been used as a primary outcome…

  20. Tide-related biological rhythm in the oxygen consumption rate of ghost shrimp (Neotrypaea uncinata).

    PubMed

    Leiva, Félix P; Niklitschek, Edwin J; Paschke, Kurt; Gebauer, Paulina; Urbina, Mauricio A

    2016-07-01

    The effects of tidal height (high and low), acclimation to laboratory conditions (days in captivity) and oxygen level (hypoxia and normoxia) were evaluated in the oxygen consumption rate (OCR) of the ghost shrimp Neotrypaea uncinata We evaluated the hypothesis that N. uncinata reduces its OCR during low tide and increases it during high tide, regardless of oxygen level or acclimation. Additionally, the existence of an endogenous rhythm in OCR was explored, and we examined whether it synchronized with tidal, diurnal or semidiurnal cycles. Unexpectedly, high OCRs were observed at low tide, during normoxia, in non-acclimated animals. Results from a second, longer experiment under normoxic conditions suggested the presence of a tide-related metabolic rhythm, a response pattern not yet demonstrated for a burrowing decapod. Although rhythms persisted for only 2 days after capture, their period of 12.8 h closely matched the semidiurnal tidal cycle that ghost shrimp confront inside their burrows. PMID:27099365

  1. Oxygen ionization rates at Mars and Venus - Relative contributions of impact ionization and charge exchange

    NASA Technical Reports Server (NTRS)

    Zhang, M. H. G.; Luhmann, J. G.; Nagy, A. F.; Spreiter, J. R.; Stahara, S. S.

    1993-01-01

    Oxygen ion production rates above the ionopauses of Venus and Mars are calculated for photoionization, charge exchange, and solar wind electron impact ionization processes. The latter two require the use of the Spreiter and Stahara (1980) gas dynamic model to estimate magnetosheath velocities, densities, and temperatures. The results indicate that impact ionization is the dominant mechanism for the production of O(+) ions at both Venus and Mars. This finding might explain both the high ion escape rates measured by Phobos 2 and the greater mass loading rate inferred for Venus from the bow shock positions.

  2. The Effect of Acetazolamide on Cerebral Blood Flow and Oxygen Utilization in the Rhesus Monkey

    PubMed Central

    Laux, B. E.; Raichle, M. E.

    1978-01-01

    The brain is critically dependent for its moment to moment function and survival on an adequate supply of oxygen. The enzyme carbonic anhydrase (EC 4.2.1.1) may play an important role in oxygen delivery to brain tissue by facilitating the hydration of metabolically produced carbon dioxide in erythrocytes in brain capillaries, thus permitting the Bohr effect to occur. We examined the effect of 30 mg/kg i.v. acetazolamide, a potent inhibitor of carbonic anhydrase, upon cerebral blood flow and oxygen consumption in lightly anesthetized, passively ventilated rhesus monkeys. Cerebral blood flow and oxygen consumption were measured with oxygen-15-labeled water and oxygen-15-labeled oxyhemoglobin, respectively, injected into the internal carotid artery and monitored externally. Acetazolamide produced an immediate and significant increase in cerebral blood flow (from a mean of 64.7 to 83.8 ml/100 g per min), an increase in arterial carbon dioxide tension (from a mean of 40.7 to 47.5 torr), and a decrease in cerebral oxygen consumption (from a mean of 4.16 to 2.82 ml/100 g per min). Because the change in cerebral oxygen consumption occurred within minutes of the administration of acetazolamide, we believe that this effect probably was not due to a direct action on brain cells but was achieved by an interference with oxygen unloading in brain capillaries. A resultant tissue hypoxia might well explain part of the observed increase in cerebral blood flow. PMID:99455

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

    NASA Astrophysics Data System (ADS)

    Boyarski, Adam M.

    2009-06-01

    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.

  4. Polymer Growth Rate in a Wire Chamber with Oxygen,Water, or Alcohol Gas Additives

    SciTech Connect

    Boyarski, Adam; /SLAC

    2008-07-02

    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 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 stored in the polymer layer and that a high electric field is necessary to remove the charge.

  5. Limits on oxygen concentration in the prebiological atmosphere and the rate of abiotic fixation of nitrogen

    NASA Astrophysics Data System (ADS)

    Kasting, J. F.; Walker, J. C. G.

    1981-02-01

    Two possible scenarios in early terrestrial atmospheric evolution are examined using a one-dimensional chemistry and flow model of the atmosphere. In each case the production of oxygen results from photolysis of H2O followed by the escape of hydrogen to space. In case 1 the rate of release of reduced volcanic gases is assumed to be greater than the oxygen production rate in leading to ground-level-oxygen concentrations on the order of 10 to the -13th PAL (present atmospheric level). In case 2, the volcanic reduced gas source is omitted, as in the case during an extended period of decreased tectonic activity. The oxygen concentration would then have been limited to about 4 x 10 to the -8th PAL by reaction with dissolved ferrous iron in the early oceans. The case 1 atmosphere is reducing, and the case 2 atmosphere oxidizing, based on the relative concentrations of reduced versus oxidized radical species present in the troposphere. The NO produced by lightning discharges is converted primarily to HNO in case 1 and to HNO3 in case 2.

  6. Oxygen additive amount dependence of rate of photoresist removal by H radicals generated on a tungsten hot-wire catalyst

    NASA Astrophysics Data System (ADS)

    Yamamoto, Masashi; Umemoto, Hironobu; Ohdaira, Keisuke; Shikama, Tomokazu; Nishiyama, Takashi; Horibe, Hideo

    2016-07-01

    We examined an environmentally friendly photoresist removal method using radicals produced by decomposing mixtures of hydrogen and oxygen on a hot tungsten catalyst. The photoresist removal rate increased with the oxygen additive amount (the flow rate ratio of oxygen to hydrogen) up to an optimal amount and then decreased gradually. When the catalyst temperature was 1600 °C, the optimal oxygen additive amount was 1.0% and the removal rate was 1.7 times higher than that in the pure hydrogen system. At 2000 °C, the optimal amount increased to 2.5% but the increase ratio decreased by 1.3 times. At high catalyst temperatures, the absolute removal rate as well as the optimal oxygen additive amount is high, but the increase ratio is low. At the optimal oxygen additive amount, H, O, and OH radicals may exert their effects together to decompose photosensitive polymers.

  7. Utilization of native oxygen in Eu(RE)-doped GaN for enabling device compatibility in optoelectronic applications

    DOE PAGESBeta

    Mitchell, Brandon; Timmerman, D.; Poplawsky, Jonathan D.; Zhu, W.; Lee, D.; Wakamatsu, R.; Takatsu, J.; Matsuda, M.; Guo, Wei; Lorenz, K.; et al

    2016-01-04

    The detrimental influence of oxygen on the performance and reliability of V/III nitride based devices is well known. However, the influence of oxygen on the nature of the incorporation of other co-dopants, such as rare earth ions, has been largely overlooked in GaN. Here, we report the first comprehensive study of the critical role that oxygen has on Eu in GaN, as well as atomic scale observation of diffusion and local concentration of both atoms in the crystal lattice. We find that oxygen plays an integral role in the location, stability, and local defect structure around the Eu ions thatmore » were doped into the GaN host. Although the availability of oxygen is essential for these properties, it renders the material incompatible with GaN-based devices. However, the utilization of the normally occurring oxygen in GaN is promoted through structural manipulation, reducing its concentration by 2 orders of magnitude, while maintaining both the material quality and the favorable optical properties of the Eu ions. Furthermore, these findings open the way for full integration of RE dopants for optoelectronic functionalities in the existing GaN platform.« less

  8. Utilization of native oxygen in Eu(RE)-doped GaN for enabling device compatibility in optoelectronic applications

    NASA Astrophysics Data System (ADS)

    Mitchell, B.; Timmerman, D.; Poplawsky, J.; Zhu, W.; Lee, D.; Wakamatsu, R.; Takatsu, J.; Matsuda, M.; Guo, W.; Lorenz, K.; Alves, E.; Koizumi, A.; Dierolf, V.; Fujiwara, Y.

    2016-01-01

    The detrimental influence of oxygen on the performance and reliability of V/III nitride based devices is well known. However, the influence of oxygen on the nature of the incorporation of other co-dopants, such as rare earth ions, has been largely overlooked in GaN. Here, we report the first comprehensive study of the critical role that oxygen has on Eu in GaN, as well as atomic scale observation of diffusion and local concentration of both atoms in the crystal lattice. We find that oxygen plays an integral role in the location, stability, and local defect structure around the Eu ions that were doped into the GaN host. Although the availability of oxygen is essential for these properties, it renders the material incompatible with GaN-based devices. However, the utilization of the normally occurring oxygen in GaN is promoted through structural manipulation, reducing its concentration by 2 orders of magnitude, while maintaining both the material quality and the favorable optical properties of the Eu ions. These findings open the way for full integration of RE dopants for optoelectronic functionalities in the existing GaN platform.

  9. Utilization of native oxygen in Eu(RE)-doped GaN for enabling device compatibility in optoelectronic applications

    PubMed Central

    Mitchell, B.; Timmerman, D.; Poplawsky, J.; Zhu, W.; Lee, D.; Wakamatsu, R.; Takatsu, J.; Matsuda, M.; Guo, W.; Lorenz, K.; Alves, E.; Koizumi, A.; Dierolf, V.; Fujiwara, Y.

    2016-01-01

    The detrimental influence of oxygen on the performance and reliability of V/III nitride based devices is well known. However, the influence of oxygen on the nature of the incorporation of other co-dopants, such as rare earth ions, has been largely overlooked in GaN. Here, we report the first comprehensive study of the critical role that oxygen has on Eu in GaN, as well as atomic scale observation of diffusion and local concentration of both atoms in the crystal lattice. We find that oxygen plays an integral role in the location, stability, and local defect structure around the Eu ions that were doped into the GaN host. Although the availability of oxygen is essential for these properties, it renders the material incompatible with GaN-based devices. However, the utilization of the normally occurring oxygen in GaN is promoted through structural manipulation, reducing its concentration by 2 orders of magnitude, while maintaining both the material quality and the favorable optical properties of the Eu ions. These findings open the way for full integration of RE dopants for optoelectronic functionalities in the existing GaN platform. PMID:26725651

  10. Utilization of native oxygen in Eu(RE)-doped GaN for enabling device compatibility in optoelectronic applications.

    PubMed

    Mitchell, B; Timmerman, D; Poplawsky, J; Zhu, W; Lee, D; Wakamatsu, R; Takatsu, J; Matsuda, M; Guo, W; Lorenz, K; Alves, E; Koizumi, A; Dierolf, V; Fujiwara, Y

    2016-01-01

    The detrimental influence of oxygen on the performance and reliability of V/III nitride based devices is well known. However, the influence of oxygen on the nature of the incorporation of other co-dopants, such as rare earth ions, has been largely overlooked in GaN. Here, we report the first comprehensive study of the critical role that oxygen has on Eu in GaN, as well as atomic scale observation of diffusion and local concentration of both atoms in the crystal lattice. We find that oxygen plays an integral role in the location, stability, and local defect structure around the Eu ions that were doped into the GaN host. Although the availability of oxygen is essential for these properties, it renders the material incompatible with GaN-based devices. However, the utilization of the normally occurring oxygen in GaN is promoted through structural manipulation, reducing its concentration by 2 orders of magnitude, while maintaining both the material quality and the favorable optical properties of the Eu ions. These findings open the way for full integration of RE dopants for optoelectronic functionalities in the existing GaN platform. PMID:26725651

  11. Rate constant for the reaction of atomic oxygen with phosphine at 298 K

    NASA Technical Reports Server (NTRS)

    Stief, L. J.; Payne, W. A.; Nava, D. F.

    1987-01-01

    The rate constant for the reaction of atomic oxygen with phosphine has been measured at 298 K using flash photolysis combined with time-resolved detection of O(3P) via resonance fluorescence. Atomic oxygen was produced by flash photolysis of N2O or NO highly diluted in argon. The results were shown to be independent of (PH3), (O), total pressure and the source of O(3P). The mean value of all the experiments is k1 = (3.6 + or -0.8) x 10 to the -11th cu cm/s (1 sigma). Two previous measurements of k1 differed by more than an order of magnitude, and the results support the higher value obtained in a discharge flow-mass spectrometry study. A comparison with rate data for other atomic and free radical reactions with phosphine is presented, and the role of these reactions in the aeronomy or photochemistry of Jupiter and Saturn is briefly considered.

  12. Rate of oxygen consumption in seasonal and non-seasonal depression.

    PubMed

    Pinchasov, Boris B; Grischin, Oleg V; Putilov, Arcady A

    2002-04-01

    Most depressives suffer from weight loss, anorexia and insomnia, while for winter depressives the typical symptoms are weight gain, carbohydrate craving, overeating, oversleeping and extreme lack of energy. It is important to know whether winter depressives differ from most other depressives on measures of energy regulation. In wintertime, we evaluated the rate of oxygen consumption in relationship to neuro-vegetative depressive symptoms in 92 Siberian women. The seated subjects underwent oxyspirography in the mid-morning (1.5 hours after a standard breakfast). It was found that the oxygen consumption rate was similar in non-depressed women (n = 25) and depressed women with non-seasonal depression (n = 27). The comparatively lower values were obtained in women with winter depression (n = 40). This finding supports the suggestion that the behaviour disturbances typical for winter depression may represent a physiological feedback loop to energy conservation. PMID:12479083

  13. Childhood asthma utilization rates in a nonsmoking population of utah compared to state and national rates.

    PubMed

    Gren, Lisa H; Taylor, Brooke; Lyon, Joseph L

    2011-01-01

    Risk factors, such as parental smoking, are commonly associated with increased asthma symptoms and hospitalizations of children. Deseret Mutual Benefits Administrators (DMBA) is the health insurer for employees of The Church of Jesus Christ of Latter-day Saints and their families. Due to religious proscription, employees abstain from alcohol and tobacco use, creating a cohort of children not exposed to parental smoking. Calculation of hospitalization rates for DMBA, Utah, and the US were made in children to compare rates between a nonsmoking population and general populations. Compared to DMBA, rate ratios for asthma hospitalization and emergency department asthma visits were higher for the US and Utah. The incidence of hospital outpatient department and physician office visits was significantly greater for the US population compared to the DMBA. This study demonstrates a decreased need for health services used by children not exposed to second-hand smoke. PMID:22389787

  14. Specific oxygen uptake rate variations during batch fermentation of Bacillus thuringiensis subspecies kurstaki HD-1.

    PubMed

    Rowe, Gerald E; Margaritis, Argyrios; Wei, Ning

    2003-01-01

    The specific oxygen uptake rate (q(O)2, respiration rate) of Bacillus thuringiensis subsp. kurstaki HD-1 was very high at inoculation and was found to decrease essentially monotonically throughout both vegetative growth phase and transition phase under different batch culture conditions. Average q(O)2 values decreased from 8-10 mmol/g h at 1 h after inoculation to less than 2 mmol/g h by the time growth ended. The results are shown to be consistent with the few previous reports on q(O)2 in B. thuringiensis in the literature but also novel in that this pattern of monotonic decline has not been described previously. Both pH control and EDTA in low concentration shortened the vegetative growth phase and reduced the 10 h biomass concentration. Using plots of q(O)2 versus specific growth rate, mu, biomass yield based on the oxygen used for growth, was calculated for transition phase to be 0.041-0.047 g/mmol, consistent with literature values. The same plot also showed that the presence of EDTA resulted in an atypical q(O)2-mu trajectory and apparently much higher biomass yield from the oxygen consumed. PMID:14524704

  15. Rates and mechanisms of the atomic oxygen reaction with nickel at elevated temperatures

    NASA Technical Reports Server (NTRS)

    Christian, J. D.; Gilbreath, W. P.

    1973-01-01

    The oxidation of nickel by atomic oxygen at pressure from 1 to 45 N/sq m between 1050 and 1250 K was investigated. In these ranges, the oxidation was found to follow the parobolic rate law, viz., K sub p = 0.0000114 exp(-13410/T) g squared/cm4/sec for films of greater than 1 micron thickness and was pressure independent. The activation enthalpy for the oxidation reaction was 112 + or - 11 kj/mole (27 + or - 3 kcal/mole). Of a number of possible mechanisms and defect structures considered, it was shown that the most likely was a saturated surface defect model for atomic oxidation, based on reaction activation enthalpies, impurity effects, pressure independence, and magnitudes of rates. A model judged somewhat less likely was one having doubly ionized cationic defects rate controlling in both atomic and molecular oxygen. From comparisons of the appropriate processes, the following enthalpy values were derived: enthalpy of activation (Ni diffusion in Ni0) = 110 + or - 30 kj/mole and standard enthalpy change for reaction formation (doubly ionized cation vacancies in Ni0 from atomic oxygen)= -9 + or - 25 kj/mole.

  16. The Balancing Act: How Utility Rates Are Decided. Teacher/Facilitator's Guide.

    ERIC Educational Resources Information Center

    American Gas Association, Arlington, VA. Educational Services.

    Designed for secondary level students, this guide describes the process of establishing utility rates for gas, electricity, telephone, or water services. Insights are presented into the parties and interests involved in rate changes, along with procedures and issues that influence decision-making. The goals of this teaching guide include: (1)…

  17. Public Utility Regulatory Policies Act of 1978: Natural Gas Rate Design Study

    SciTech Connect

    1980-05-01

    First, the comments on May 3, 1979 Notice of Inquiry of DOE relating to the Gas Utility Rate Design Study Required by Section 306 of PURPA are presented. Then, comments on the following are included: (1) ICF Gas Utility Model, Gas Utility Model Data Outputs, Scenario Design; (2) Interim Model Development Report with Example Case Illustrations; (3) Interim Report on Simulation of Seven Rate Forms; (4) Methodology for Assessing the Impacts of Alternative Rate Designs on Industrial Energy Use; (5) Simulation of Marginal-Cost-Based Natural Gas Rates; and (6) Preliminary Discussion Draft of the Gas Rate Design Study. Among the most frequent comments expressed were the following: (a) the public should be given the opportunity to review the final report prior to its submission to Congress; (b) results based on a single computer model of only four hypothetical utility situations cannot be used for policy-making purposes for individual companies or the entire gas industry; (c) there has been an unobjective treatment of traditional and economic cost rate structures; the practical difficulties and potential detrimental consequences of economic cost rates are not fully disclosed; and (d) it is erroneous to assume that end users, particularly residential customers, are influenced by price signals in the rate structure, as opposed to the total bill.

  18. Efficient generation in a chemical oxygen - iodine laser with a low buffer-gas flow rate

    SciTech Connect

    Azyazov, V N; Safonov, V S; Ufimtsev, N I

    2002-09-30

    The efficient generation in a chemical oxygen - iodine laser (COIL) with a low buffer-gas flow rate for Mach numbers M {<=} 1 is demonstrated. The maximum output power of the COIL was 415 W for a molecular chlorine flow rate of 20 mmol s{sup -1}, which corresponds to a chemical efficiency {eta}{sub ch} =23%. It is shown that the substitution of the buffer gas CO{sub 2} for N{sub 2} does not cause any significant variation in the dependence of the output power on the degree of dilution of the active medium. (lasers)

  19. Protein expression and oxygen consumption rate of early postmortem mitochondria relate to meat tenderness.

    PubMed

    Grabež, V; Kathri, M; Phung, V; Moe, K M; Slinde, E; Skaugen, M; Saarem, K; Egelandsdal, B

    2015-04-01

    Oxygen consumption rate (OCR) of muscle fibers from bovine semimembranosus muscle of 41 animals was investigated 3 to 4 h and 3 wk postmortem. Significant relations (P < 0.05) were found between OCR measurements and Warner-Bratzler shear force measurement. Muscles with high mitochondrial OCR after 3 to 4 h and low nonmitochondrial oxygen consumption gave more tender meat. Tender (22.92 ± 2.2 N/cm2) and tough (72.98 ± 7.2 N/cm2) meat samples (4 samples each), separated based on their OCR measurements, were selected for proteomic studies using mitochondria isolated approximately 2.5 h postmortem. Twenty-six differently expressed proteins (P < 0.05) were identified in tender meat and 19 in tough meat. In tender meat, the more prevalent antioxidant and chaperon enzymes may reduce reactive oxygen species and prolong oxygen removal by the electron transport system (ETS). Glycolytic, Krebs cycle, and ETS enzymes were also more abundant in tender meat PMID:26020220

  20. ENHANCED BIOREMEDIATION UTILIZING HYDROGEN PEROXIDE AS A SUPPLEMENTAL SOURCE OF OXYGEN: A LABORATORY AND FIELD STUDY

    EPA Science Inventory

    Laboratory and field scale studies were conducted to investigate the feasibility of using hydrogen peroxide as a supplemental source of oxygen for bioremediation of an aviation gasoline fuel spill. Field samples of aviation gasoline contaminated aquifer material were artificially...

  1. Shaped Ir-Ni bimetallic nanoparticles for minimizing Ir utilization in oxygen evolution reaction.

    PubMed

    Lim, Jinkyu; Yang, Sungeun; Kim, Chanyeon; Roh, Chi-Woo; Kwon, Yongwoo; Kim, Yong-Tae; Lee, Hyunjoo

    2016-04-12

    Shaped Ir-Ni bimetallic nanoparticles were synthesized and used for electrocatalytic oxygen evolution reaction (OER). The obtained bimetallic nanoparticles showed significantly enhanced Ir mass activity and durability compared with Ir nanoparticles. PMID:27034092

  2. Effects of temperature and dissolved oxygen content on oxygen consumption rate of Chinese prawn, giant tiger prawn and giant freshwater prawn

    NASA Astrophysics Data System (ADS)

    Dai, Xi-Lin; Zang, Wei-Ling; Wang, Wei-Dong; Shi, Yong-Hai; Liu, Wen-Cui; Xu, Gui-Rong; Li, Shi-Hua

    1999-06-01

    Temperature and the dissolved oxygen content affect the oxygen consumption of juveniles of Chinese prawn ( Penaeus chinensis), giant tiger prawn ( P. monodon) and giant freshwater prawn ( Macrobrachium rosenbergii). There is good correlation between the oxygen consumption rate ( V, mg/g·h) of the above three prawn species and the water temperature, and dissolved oxygen. In the range of test temperature, V increased with water temperature and dissolved oxygen content. The V of the above three prawn species increased 0.085 mg/g·h, 0.093 mg/g·h and 0.08 mg/g·h respectively with each °C of rising temperature. The comatose point and stifling point of the juveniles rose obviously at unsuitable temperature.

  3. The relationship between body temperature, heart rate, breathing rate, and rate of oxygen consumption, in the tegu lizard (Tupinambis merianae) at various levels of activity.

    PubMed

    Piercy, Joanna; Rogers, Kip; Reichert, Michelle; Andrade, Denis V; Abe, Augusto S; Tattersall, Glenn J; Milsom, William K

    2015-12-01

    The present study determined whether EEG and/or EMG recordings could be used to reliably define activity states in the Brazilian black and white tegu lizard (Tupinambis merianae) and then examined the interactive effects of temperature and activity states on strategies for matching O2 supply and demand. In a first series of experiments, the rate of oxygen consumption (VO2), breathing frequency (fR), heart rate (fH), and EEG and EMG (neck muscle) activity were measured in different sleep/wake states (sleeping, awake but quiet, alert, or moving). In general, metabolic and cardio-respiratory changes were better indictors of the transition from sleep to wake than were changes in the EEG and EMG. In a second series of experiments, the interactive effects of temperature (17, 27 and 37 °C) and activity states on fR, tidal volume (VT), the fraction of oxygen extracted from the lung per breath (FIO2-FEO2), fH, and the cardiac O2 pulse were quantified to determine the relative roles of each of these variables in accommodating changes in VO2. The increases in oxygen supply to meet temperature- and activity-induced increases in oxygen demand were produced almost exclusively by increases in fH and fR. Regression analysis showed that the effects of temperature and activity state on the relationships between fH, fR and VO2 was to extend a common relationship along a single curve, rather than separate relationships for each metabolic state. For these lizards, the predictive powers of fR and fH were maximized when the effects of changes in temperature, digestive state and activity were pooled. However, the best r(2) values obtained were 0.63 and 0.74 using fR and fH as predictors of metabolic rate, respectively. PMID:26285591

  4. Application of the gas tracer method for measuring oxygen transfer rates in subsurface flow constructed wetlands.

    PubMed

    Tyroller, Lina; Rousseau, Diederik P L; Santa, Santa; García, Joan

    2010-07-01

    The oxygen transfer rate (OTR) has a significant impact on the design, optimal operation and modelling of constructed wetlands treating wastewater. Oxygen consumption is very fast in wetlands and the OTR cannot be determined using an oxygen mass balance. This problem is circumvented in this study by applying the gas tracer method. Experiments were conducted in an unplanted gravel bed (dimensions L x W x d 125 x 50 x 35 cm filled with a 30-cm layer of 10-11-mm gravel) and a planted horizontal subsurface flow constructed wetland (HSSFCW) (L x W x d 110 x 70 x 38 cm filled with a 30-cm layer of 3.5-mm gravel with Phragmites australis). Tap water saturated with propane as gas tracer (pure or commercial cooking gas, depending on the test) was used. The mass transfer ratio between oxygen and commercial propane gas was quite constant and averaged R = 1.03, which is slightly lower than the value of R = 1.39 that is usually reported for pure propane. The OTR ranged from 0.31 to 5.04 g O(2) m(-2) d(-1) in the unplanted gravel bed and from 0.3 to 3.2 g O(2) m(-2) d(-1) in the HSSFCW, depending on the hydraulic retention time (HRT). The results of this study suggest that the OTR in HSSFCW is very low for the oxygen demand of standard wastewater and the OTR calculations based on mass balances and theoretical stoichiometric considerations overestimate OTR values by a factor that ranges from 10 to 100. The gas tracer method is a promising tool for determining OTR in constructed wetlands, with commercial gas proving to be a viable low-cost alternative for determining OTR. PMID:20542312

  5. Relative rate constants for the reactions of atomic oxygen with HO2 anad OH radicals

    NASA Technical Reports Server (NTRS)

    Keyser, L. F.

    1983-01-01

    Relative rate constants for the reactions O + HO2 - OH + O2 (1) and O + OH - H + O2 (2) were obtained by using the discharge-flow resonance fluorescence technique at 2 torr total pressure and 299 K. HO2 radicals were generated by reacting atomic hydrogen with an excess of O2. Quasi-steady-state concentrations of OH and HO2 were established in the presence of excess atomic oxygen. Observed concentration ratios, namely the ratio of the OH concentration to the HO2 concentration, resulted in a value of 1.7 + or 0.2 for k1/k2. The error limits are twice the standard deviation obtained from the data analysis. Overall experimental error is estimated to be + or - 25 percent. This result confirms earlier direct measurements of k1 and k2 which required knowledge of absolute radical or atomic oxygen concentrations.

  6. Influence of oxygen transfer on Pseudomonas putida effects on growth rate and biodesulfurization capacity.

    PubMed

    Escobar, S; Rodriguez, A; Gomez, E; Alcon, A; Santos, V E; Garcia-Ochoa, Felix

    2016-04-01

    The growth rate and desulfurization capacity accumulated by the cells during the growth of Pseudomonas putida KTH2 under different oxygen transfer conditions in a stirred and sparged tank bioreactor have been studied. Hydrodynamic conditions were changed using different agitation conditions. During the culture, several magnitudes associated to growth, such as the specific growth rate, the dissolved oxygen concentration and the carbon source consumption have been measured. Experimental results indicate that cultures are influenced by the fluid dynamic conditions into the bioreactor. An increase in the stirrer speed from 400 to 700 rpm has a positive influence on the cell growth rate. Nevertheless, the increase of agitation from 700 to 2000 rpm hardly has any influence on the growth rate. The effect of fluid dynamics on the cells development of the biodesulfurization (BDS) capacity of the cells during growth is different. The activities of the intracellular enzymes involved in the 4S pathway change with dissolved oxygen concentration. The enzyme activities have been evaluated in cells at several growth time and different hydrodynamic conditions. An increase of the agitation from 100 to 300 rpm has a positive influence on the development of the overall BDS capacity of the cells during growth. This capacity shows a decrease for higher stirrer speeds and the activity of the enzymes monooxygenases DszC and DszA decreases dramatically. The highest value of the activity of DszB enzyme was obtained with cells cultured at 100 rpm, while this activity decreases when the stirrer speed was increased higher than this value. PMID:26762940

  7. 40 CFR Table I-13 to Subpart I of... - Default Emission Factors (1-Uij) for Gas Utilization Rates (Uij) and By-Product Formation Rates...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Electronics... Gas Utilization Rates (Uij) and By-Product Formation Rates (Bijk) for LCD Manufacturing for Use With...) for Gas Utilization Rates (Uij) and By-Product Formation Rates (Bijk) for LCD Manufacturing for...

  8. 40 CFR Table I-14 to Subpart I of... - Default Emission Factors (1-Uij) for Gas Utilization Rates (Uij) and By-Product Formation Rates...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Electronics... Gas Utilization Rates (Uij) and By-Product Formation Rates (Bijk) for PV Manufacturing for Use With...) for Gas Utilization Rates (Uij) and By-Product Formation Rates (Bijk) for PV Manufacturing for...

  9. 40 CFR Table I-15 to Subpart I of... - Default Emission Factors (1-Uij) for Gas Utilization Rates (Uij) and By-Product Formation Rates...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Default Emission Factors (1-Uij) for Gas Utilization Rates (Uij) and By-Product Formation Rates (Bijk) for MEMS Manufacturing for Use With...) for Gas Utilization Rates (Uij) and By-Product Formation Rates (Bijk) for MEMS Manufacturing for...

  10. 40 CFR Table I-3 to Subpart I of... - Default Emission Factors (1-Uij) for Gas Utilization Rates (Uij) and By-Product Formation Rates...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Default Emission Factors (1-Uij) for Gas Utilization Rates (Uij) and By-Product Formation Rates (Bijk) for Semiconductor Manufacturing for... Gas Utilization Rates (Uij) and By-Product Formation Rates (Bijk) for Semiconductor Manufacturing...

  11. 40 CFR Table I-3 to Subpart I of... - Default Emission Factors (1-Uij) for Gas Utilization Rates (Uij) and By-Product Formation Rates...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Default Emission Factors (1-Uij) for Gas Utilization Rates (Uij) and By-Product Formation Rates (Bijk) for Semiconductor Manufacturing for... Factors (1-Uij) for Gas Utilization Rates (Uij) and By-Product Formation Rates (Bijk) for...

  12. 40 CFR Table I-4 to Subpart I of... - Default Emission Factors (1-Uij) for Gas Utilization Rates (Uij) and By-Product Formation Rates...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Default Emission Factors (1-Uij) for Gas Utilization Rates (Uij) and By-Product Formation Rates (Bijk) for Semiconductor Manufacturing for... Factors(1-Uij) for Gas Utilization Rates (Uij) and By-Product Formation Rates (Bijk) for...

  13. Effects of oxygen, salt, and pH level on corrosion rate of drill-stem steel

    SciTech Connect

    Weirick, L.J.

    1982-11-01

    A technique proposed to control corrosion of the drill pipe is removal of oxygen from the drilling fluid. One approach to oxygen reduction is to substitute an anaerobic gas for air in the drilling fluid. A critical question to be answered when designing the anaerobic gas generator is what level of oxygen concentration is acceptable within the inert gas such that a low corrosion rate will be maintained. A laboratory program was done to answer this question. The program was designed to determine the effect of oxygen content, salt concentration and pH level on the corrosion rate of plain carbon steel. The corrosion rate of steel was found to decrease with increasing salt concentration at fixed pH levels and with oxygen contents in solution at equilibrium with air at 90/sup 0/C. The corrosion rate was found to decrease with increasing pH at fixed concentrations of salt and oxygen at 90/sup 0/C. The corrosion rate was also found to be proportional to the dissolved oxygen concentration at fixed pH levels and salt concentration. It is recommended that the anaerobic gas generator be designed to lower the oxygen concentration one order of magnitude below that in solution in equilibrium with air, that is, to approximately 500 ppB at 90/sup 0/C.

  14. Evolution of oxygen utilization in multicellular organisms and implications for cell signalling in tissue engineering

    PubMed Central

    Stamati, Katerina; Mudera, Vivek

    2011-01-01

    Oxygen is one of the critically defining elements resulting in the existence of eukaryotic life on this planet. The rise and fall of this element can be tracked through time and corresponds with the evolution of diverse life forms, development of efficient energy production (oxidative phosphorylation) in single cell organisms, the evolution of multicellular organisms and the regulation of complex cell phenotypes. By understanding these events, we can plot the effect of oxygen on evolution and its direct influence on different forms of life today, from the whole organism to specific cells within multicellular organisms. In the emerging field of tissue engineering, understanding the role of different levels of oxygen for normal cell function as well as control of complex signalling cascades is paramount to effectively build 3D tissues in vitro and their subsequent survival when implanted. PMID:22292107

  15. Heart rate variability of human in hypoxic oxygen-argon environment

    NASA Astrophysics Data System (ADS)

    Khayrullina, Rezeda; Smoleevskiy, Alexandr; Bubeev, Yuri

    Human adaptive capacity, reliability and stability in extreme environments depend primarily on the individual resistance to stresses, includes both innate and acquired components. We have conducted studies in six healthy subjects - men aged between 24 to 42 years who psychophysiological indicators acterizing the severity of stress reactions studied directly during an emergency situation, before and after it. The subjects were in a hypoxic oxygen-argon atmosphere 10 days. Cardiovascular system is one of the first to respond to stressful reaction. The method of heart rate variability (HRV) allows us to estimate balance of sympathetic and parasympathetic parts of vegetative nervous system. In the course of the baseline study it was found that resting heart rate (HR) in the examined individuals is within normal limits. During the experiment in all subjects there was a trend towards more frequent heartbeat. Each subject at one stage or another stay in a hypoxic oxygen-argon environment heart rate go beyond the group norm, but the extent and duration of these abnormalities were significantly different. Marked increase in middle heart rate during of subjects experiment, fluctuating within a wide range (from 2.3% to 29.1%). Marked increase in middle heart rate during of subjects experiment, fluctuating within a wide range (from 2.3% to 29.1%). This suggests that the ability to adapt to living in the investigated gas environment have marked individual differences. SDNN (mean square deviation of all R-R intervals) is the integral indicator of the total effect of the sinus node to the sympathetic and parasympathetic parts of vegetative nervous system, as well as indicating the higher functional reserves of the cardiovascular systems. Increase in heart rate in the majority of subject was accompanied by an increase in individual SDNN. This suggests that the parasympathetic system is able to balance the increase in activity of the sympathetic system, and functional reserves are

  16. Pedaling rate is an important determinant of human oxygen uptake during exercise on the cycle ergometer

    PubMed Central

    Formenti, Federico; Minetti, Alberto E; Borrani, Fabio

    2015-01-01

    Estimation of human oxygen uptake () during exercise is often used as an alternative when its direct measurement is not feasible. The American College of Sports Medicine (ACSM) suggests estimating human during exercise on a cycle ergometer through an equation that considers individual's body mass and external work rate, but not pedaling rate (PR). We hypothesized that including PR in the ACSM equation would improve its prediction accuracy. Ten healthy male participants’ (age 19–48 years) were recruited and their steady-state was recorded on a cycle ergometer for 16 combinations of external work rates (0, 50, 100, and 150 W) and PR (50, 70, 90, and 110 revolutions per minute). was calculated by means of a new equation, and by the ACSM equation for comparison. Kinematic data were collected by means of an infrared 3-D motion analysis system in order to explore the mechanical determinants of . Including PR in the ACSM equation improved the accuracy for prediction of sub-maximal during exercise (mean bias 1.9 vs. 3.3 mL O2 kg−1 min−1) but it did not affect the accuracy for prediction of maximal (P > 0.05). Confirming the validity of this new equation, the results were replicated for data reported in the literature in 51 participants. We conclude that PR is an important determinant of human during cycling exercise, and it should be considered when predicting oxygen consumption. PMID:26371230

  17. Influence of Prolonged Spaceflight on Heart Rate and Oxygen Uptake Kinetics

    NASA Astrophysics Data System (ADS)

    Hoffmann, U.; Moore, A.; Drescher, U.

    2013-02-01

    During prolonged spaceflight, physical training is used to minimize cardiovascular deconditioning. Measurement of the kinetics of cardiorespiratory parameters, in particular the kinetic analysis of heart rate, respiratory and muscular oxygen uptake, provides useful information with regard to the efficiency and regulation of the cardiorespiratory system. Practically, oxygen uptake kinetics can only be measured at the lung site (V’O2 resp). The dynamics of V’O2 resp, however, is not identical with the dynamics at the site of interest: skeletal muscle. Eight Astronauts were tested pre- and post-flight using pseudo random binary workload changes between 30 and 80 W. Their kinetic responses of heart rate, respiratory as well as muscular V’O2 kinetics were estimated by using time-series analysis. Statistical analysis revealed that the kinetic responses of respiratory as well as muscular V’O2 kinetics are slowed post-flight than pre-flight. Heart rate seems not to be influenced following flight. The influence of other factors (e. g. astronauts’ exercise training) may impact these parameters and is an area for future studies.

  18. Individuals with higher metabolic rates have lower levels of reactive oxygen species in vivo

    PubMed Central

    Salin, Karine; Auer, Sonya K.; Rudolf, Agata M.; Anderson, Graeme J.; Cairns, Andrew G.; Mullen, William; Hartley, Richard C.; Selman, Colin; Metcalfe, Neil B.

    2015-01-01

    There is increasing interest in the effect of energy metabolism on oxidative stress, but much ambiguity over the relationship between the rate of oxygen consumption and the generation of reactive oxygen species (ROS). Production of ROS (such as hydrogen peroxide, H2O2) in the mitochondria is primarily inferred indirectly from measurements in vitro, which may not reflect actual ROS production in living animals. Here, we measured in vivo H2O2 content using the recently developed MitoB probe that becomes concentrated in the mitochondria of living organisms, where it is converted by H2O2 into an alternative form termed MitoP; the ratio of MitoP/MitoB indicates the level of mitochondrial H2O2 in vivo. Using the brown trout Salmo trutta, we tested whether this measurement of in vivo H2O2 content over a 24 h-period was related to interindividual variation in standard metabolic rate (SMR). We showed that the H2O2 content varied up to 26-fold among fish of the same age and under identical environmental conditions and nutritional states. Interindividual variation in H2O2 content was unrelated to mitochondrial density but was significantly associated with SMR: fish with a higher mass-independent SMR had a lower level of H2O2. The mechanism underlying this observed relationship between SMR and in vivo H2O2 content requires further investigation, but may implicate mitochondrial uncoupling which can simultaneously increase SMR but reduce ROS production. To our knowledge, this is the first study in living organisms to show that individuals with higher oxygen consumption rates can actually have lower levels of H2O2. PMID:26382073

  19. Individuals with higher metabolic rates have lower levels of reactive oxygen species in vivo.

    PubMed

    Salin, Karine; Auer, Sonya K; Rudolf, Agata M; Anderson, Graeme J; Cairns, Andrew G; Mullen, William; Hartley, Richard C; Selman, Colin; Metcalfe, Neil B

    2015-09-01

    There is increasing interest in the effect of energy metabolism on oxidative stress, but much ambiguity over the relationship between the rate of oxygen consumption and the generation of reactive oxygen species (ROS). Production of ROS (such as hydrogen peroxide, H2O2) in the mitochondria is primarily inferred indirectly from measurements in vitro, which may not reflect actual ROS production in living animals. Here, we measured in vivo H2O2 content using the recently developed MitoB probe that becomes concentrated in the mitochondria of living organisms, where it is converted by H2O2 into an alternative form termed MitoP; the ratio of MitoP/MitoB indicates the level of mitochondrial H2O2 in vivo. Using the brown trout Salmo trutta, we tested whether this measurement of in vivo H2O2 content over a 24 h-period was related to interindividual variation in standard metabolic rate (SMR). We showed that the H2O2 content varied up to 26-fold among fish of the same age and under identical environmental conditions and nutritional states. Interindividual variation in H2O2 content was unrelated to mitochondrial density but was significantly associated with SMR: fish with a higher mass-independent SMR had a lower level of H2O2. The mechanism underlying this observed relationship between SMR and in vivo H2O2 content requires further investigation, but may implicate mitochondrial uncoupling which can simultaneously increase SMR but reduce ROS production. To our knowledge, this is the first study in living organisms to show that individuals with higher oxygen consumption rates can actually have lower levels of H2O2. PMID:26382073

  20. Diffusion and Monod kinetics model to determine in vivo human corneal oxygen-consumption rate during soft contact lens wear

    PubMed Central

    Del Castillo, Luis F.; da Silva, Ana R. Ferreira; Hernández, Saul I.; Aguilella, M.; Andrio, Andreu; Mollá, Sergio; Compañ, Vicente

    2014-01-01

    Purpose We present an analysis of the corneal oxygen consumption Qc from non-linear models, using data of oxygen partial pressure or tension (pO2) obtained from in vivo estimation previously reported by other authors.1 Methods Assuming that the cornea is a single homogeneous layer, the oxygen permeability through the cornea will be the same regardless of the type of lens that is available on it. The obtention of the real value of the maximum oxygen consumption rate Qc,max is very important because this parameter is directly related with the gradient pressure profile into the cornea and moreover, the real corneal oxygen consumption is influenced by both anterior and posterior oxygen fluxes. Results Our calculations give different values for the maximum oxygen consumption rate Qc,max, when different oxygen pressure values (high and low pO2) are considered at the interface cornea-tears film. Conclusion Present results are relevant for the calculation on the partial pressure of oxygen, available at different depths into the corneal tissue behind contact lenses of different oxygen transmissibility. PMID:25649636

  1. On the structure and oxygen transmission rate of biodegradable cellulose nanobarriers

    PubMed Central

    2012-01-01

    Cellulose nanofibrils have been proposed for novel barrier concepts, based on their capability to form smooth, strong and transparent films, with high oxygen barrier properties. A series of cellulose-based films were manufactured and tested with respect to their oxygen transmission rate (OTR) capabilities. The obtained OTR levels were considerably better than the levels recommended for packaging applications. Part of the nanofibrillated material applied in this study was produced with 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO) mediated oxidation as pretreatment. Films made of TEMPO-pretreated samples yielded lower OTR values. The minimum obtained OTR value was 3.0 mL m-2 day-1 atm-1 with a corresponding oxygen permeability of 0.04 mL mm m-2 day-1 atm-1, tested at 50% relative humidity. The good barrier properties are due to the compact and dense structure of the films, as revealed by field-emission scanning electron microscopy. A relationship between OTR and the structure of the corresponding nanofibril-based films was confirmed. PMID:22429336

  2. Triiodothyronine facilitates weaning from extracorporeal membrane oxygenation by improved mitochondrial substrate utilization

    SciTech Connect

    Files, Matthew D.; Kajimoto, Masaki; Priddy, Colleen M.; Ledee, Dolena R.; Xu, Chun; Des Rosiers, Christine; Isern, Nancy G.; Portman, Michael A.

    2014-03-20

    Extracorporeal membrane oxygenation (ECMO) provides a bridge to recovery after myocardial injury in infants and children, yet morbidity and mortality remain high. Weaning from the circuit requires adequate cardiac contractile function, which can be impaired by metabolic disturbances induced either by ischemia-reperfusion and / or by ECMO.

  3. The Campylobacter jejuni RacRS system regulates fumarate utilization in a low oxygen environment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The natural environment of the human pathogen Campylobacter jejuni is the gastrointestinal tract of warm blooded animals. In the gut, the availability of oxygen is limited; therefore, less efficient electron acceptors such as nitrate or fumarate are used by C. jejuni. C. jejuni has a highly branched...

  4. Method and apparatus for reducing cold-phase emissions by utilizing oxygen-enriched intake air

    DOEpatents

    Poola, Ramesh B.; Sekar, Ramanujam R.; Stork, Kevin C.

    1997-01-01

    An oxygen-enriched air intake control system for an internal combustion engine includes air directing apparatus to control the air flow into the intake of the engine. During normal operation of the engine, ambient air flowing from an air filter of the engine flows through the air directing apparatus into the intake of the engine. In order to decrease the amount of carbon monoxide (CO) and hydrocarbon (HC) emissions that tend to be produced by the engine during a short period of time after the engine is started, the air directing apparatus diverts for a short period of time following the start up of the engine at least a portion of the ambient air from the air filter through a secondary path. The secondary path includes a selectively permeable membrane through which the diverted portion of the ambient air flows. The selectively permeable membrane separates nitrogen and oxygen from the diverted air so that oxygen enriched air containing from about 23% to 25% oxygen by volume is supplied to the intake of the engine.

  5. Oxygen at Nanomolar Levels Reversibly Suppresses Process Rates and Gene Expression in Anammox and Denitrification in the Oxygen Minimum Zone off Northern Chile

    PubMed Central

    Stewart, Frank J.; Thamdrup, Bo; De Brabandere, Loreto; Revsbech, Niels Peter; Ulloa, Osvaldo; Canfield, Don E.; DeLong, Edward F.

    2014-01-01

    ABSTRACT A major percentage (20 to 40%) of global marine fixed-nitrogen loss occurs in oxygen minimum zones (OMZs). Concentrations of O2 and the sensitivity of the anaerobic N2-producing processes of anammox and denitrification determine where this loss occurs. We studied experimentally how O2 at nanomolar levels affects anammox and denitrification rates and the transcription of nitrogen cycle genes in the anoxic OMZ off Chile. Rates of anammox and denitrification were reversibly suppressed, most likely at the enzyme level. Fifty percent inhibition of N2 and N2O production by denitrification was achieved at 205 and 297 nM O2, respectively, whereas anammox was 50% inhibited at 886 nM O2. Coupled metatranscriptomic analysis revealed that transcripts encoding nitrous oxide reductase (nosZ), nitrite reductase (nirS), and nitric oxide reductase (norB) decreased in relative abundance above 200 nM O2. This O2 concentration did not suppress the transcription of other dissimilatory nitrogen cycle genes, including nitrate reductase (narG), hydrazine oxidoreductase (hzo), and nitrite reductase (nirK). However, taxonomic characterization of transcripts suggested inhibition of narG transcription in gammaproteobacteria, whereas the transcription of anammox narG, whose gene product is likely used to oxidatively replenish electrons for carbon fixation, was not inhibited. The taxonomic composition of transcripts differed among denitrification enzymes, suggesting that distinct groups of microorganisms mediate different steps of denitrification. Sulfide addition (1 µM) did not affect anammox or O2 inhibition kinetics but strongly stimulated N2O production by denitrification. These results identify new O2 thresholds for delimiting marine nitrogen loss and highlight the utility of integrating biogeochemical and metatranscriptomic analyses. PMID:25352619

  6. Oxidation rate of iron sulfides as affected by surface area, morphology, oxygen concentration and autotrophic bacteria

    SciTech Connect

    Pugh, C.E.

    1984-05-01

    The relationship between surface area and rate of oxidation of Fe sulphides (pyrite and marcasite) separated from Texas lignite was studied. The reaction kinetics with respect to Fe sulphide morphology and particle size were evaluated. The oxygen concentration and the presence of autotrophic Fe and S-oxidizing bacteria (thiobacillus ferro-oxidans) on the rate of oxidation were also evaluated. The formation of sulphate from Fe sulphide was selected to measure the rate of oxidation. Relative reaction rates for different morphological forms of Fe sulphide were: marcasite > framboidal pyrite > massive pyrite. As the surface area of pyrite doubled, reaction rate increased by a factor of 1.5. Sulphate production for the 5 to 2 ..mu..m fraction was twice that of the 50 to 20 ..mu..m fraction. Reaction rate was approximately fivefold greater for non-inoculated treatments at 20% O/sub 2/ compared with 0% O/sub 2/ and was approximately ninefold greater for the same treatment inoculated with T. ferro-oxidans.

  7. Association between unemployment rates and prescription drug utilization in the United States, 2007–2010

    PubMed Central

    2012-01-01

    Background While extensive evidence suggests that the economic recession has had far reaching effects on many economic sectors, little is known regarding its impact on prescription drug utilization. The purpose of this study is to describe the association between state-level unemployment rates and retail sales of seven therapeutic classes (statins, antidepressants, antipsychotics, angiotensin-converting enzyme [ACE] inhibitors, opiates, phosphodiesterase [PDE] inhibitors and oral contraceptives) in the United States. Methods Using a retrospective mixed ecological design, we examined retail prescription sales using IMS Health Xponent™ from September 2007 through July 2010, and we used the Bureau of Labor Statistics to derive population-based rates and mixed-effects modeling with state-level controls to examine the association between unemployment and utilization. Our main outcome measure was state-level utilization per 100,000 people for each class. Results Monthly unemployment levels and rates of use of each class varied substantially across the states. There were no statistically significant associations between use of ACE inhibitors or SSRIs/SNRIs and average unemployment in analyses across states, while for opioids and PDE inhibitors there were small statistically significant direct associations, and for the remaining classes inverse associations. Analyses using each state as its own control collectively exhibited statistically significant positive associations between increases in unemployment and prescription drug utilization for five of seven areas examined. This relationship was greatest for statins (on average, a 4% increase in utilization per 1% increased unemployment) and PDE inhibitors (3% increase in utilization per 1% increased unemployment), and lower for oral contraceptives and atypical antipsychotics. Conclusion We found no evidence of an association between increasing unemployment and decreasing prescription utilization, suggesting that any

  8. 24 CFR 990.185 - Utilities expense level: Incentives for energy conservation/rate reduction.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 4 2012-04-01 2012-04-01 false Utilities expense level: Incentives for energy conservation/rate reduction. 990.185 Section 990.185 Housing and Urban Development REGULATIONS RELATING TO HOUSING AND URBAN DEVELOPMENT (CONTINUED) OFFICE OF ASSISTANT SECRETARY FOR PUBLIC AND INDIAN HOUSING, DEPARTMENT OF HOUSING...

  9. The Effect of Increased Travel Reimbursement Rates on Health Care Utilization in the VA

    ERIC Educational Resources Information Center

    Nelson, Richard E.; Hicken, Bret; West, Alan; Rupper, Randall

    2012-01-01

    Purpose: The reimbursement rate that eligible veterans receive for travel to Department of Veterans Affairs (VA) facilities increased from 11 to 28.5 cents per mile on February 1, 2008. We examined the effect of this policy change on utilization of outpatient, inpatient, and pharmacy services, stratifying veterans based on distance from a VA…

  10. Impacts of Commercial Electric Utility Rate Structure Elements on the Economics of Photovoltaic Systems

    SciTech Connect

    Ong, S.; Denholm, P.; Doris, E.

    2010-06-01

    This analysis uses simulated building data, simulated solar photovoltaic (PV) data, and actual electric utility tariff data from 25 cities to understand better the impacts of different commercial rate structures on the value of solar PV systems. By analyzing and comparing 55 unique rate structures across the United States, this study seeks to identify the rate components that have the greatest effect on the value of PV systems. Understanding the beneficial components of utility tariffs can both assist decision makers in choosing appropriate rate structures and influence the development of rates that favor the deployment of PV systems. Results from this analysis show that a PV system's value decreases with increasing demand charges. Findings also indicate that time-of-use rate structures with peaks coincident with PV production and wide ranges between on- and off-peak prices most benefit the types of buildings and PV systems simulated. By analyzing a broad set of rate structures from across the United States, this analysis provides an insight into the range of impacts that current U.S. rate structures have on PV systems.

  11. The utility of Thin Slice ratings for predicting language growth in children with autism spectrum disorder.

    PubMed

    Walton, Katherine M; Ingersoll, Brooke R

    2016-04-01

    Literature on "Thin Slice" ratings indicates that a number of personality characteristics and behaviors can be accurately predicted by ratings of very short segments (<5 min) of behavior. This study examined the utility of Thin Slice ratings of young children with autism spectrum disorder for predicting developmental skills and language gains over time. A total of 22 preschool-aged children with autism spectrum disorder participated in a battery of developmental assessments and a video-taped therapist-child interaction at Time 1. They then participated in follow-up testing of language skills and a second therapist-child interaction 6 months later (Time 2). Groups of approximately 25 naïve undergraduate students provided impression ratings ("Thin Slice ratings") about each child's skills and behaviors during 2-min segments taken from the therapist-child interaction videos at each time point. Thin Slice ratings at Time 1 were highly correlated with child scores on several developmental assessments at Time 1. In addition, Thin Slice ratings at Time 1 predicted gain in parent-reported expressive vocabulary over the course of 6 months, over and above the predictive utility of Time 1 vocabulary size. These findings provide preliminary evidence for the concurrent and predictive validity of Thin Slice ratings in young children with autism spectrum disorder. PMID:25991846

  12. Modular continuous wavelet processing of biosignals: extracting heart rate and oxygen saturation from a video signal.

    PubMed

    Addison, Paul S

    2016-06-01

    A novel method of extracting heart rate and oxygen saturation from a video-based biosignal is described. The method comprises a novel modular continuous wavelet transform approach which includes: performing the transform, undertaking running wavelet archetyping to enhance the pulse information, extraction of the pulse ridge time-frequency information [and thus a heart rate (HRvid) signal], creation of a wavelet ratio surface, projection of the pulse ridge onto the ratio surface to determine the ratio of ratios from which a saturation trending signal is derived, and calibrating this signal to provide an absolute saturation signal (SvidO2). The method is illustrated through its application to a video photoplethysmogram acquired during a porcine model of acute desaturation. The modular continuous wavelet transform-based approach is advocated by the author as a powerful methodology to deal with noisy, non-stationary biosignals in general. PMID:27382479

  13. Modular continuous wavelet processing of biosignals: extracting heart rate and oxygen saturation from a video signal

    PubMed Central

    2016-01-01

    A novel method of extracting heart rate and oxygen saturation from a video-based biosignal is described. The method comprises a novel modular continuous wavelet transform approach which includes: performing the transform, undertaking running wavelet archetyping to enhance the pulse information, extraction of the pulse ridge time–frequency information [and thus a heart rate (HRvid) signal], creation of a wavelet ratio surface, projection of the pulse ridge onto the ratio surface to determine the ratio of ratios from which a saturation trending signal is derived, and calibrating this signal to provide an absolute saturation signal (SvidO2). The method is illustrated through its application to a video photoplethysmogram acquired during a porcine model of acute desaturation. The modular continuous wavelet transform-based approach is advocated by the author as a powerful methodology to deal with noisy, non-stationary biosignals in general. PMID:27382479

  14. 40 CFR Table I-7 to Subpart I of... - Default Emission Factors (1-Uij) for Gas Utilization Rates (Uij) and By-Product Formation Rates...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Electronics Manufacturing Pt. 98, Subpt. I, Table I-7 Table I-7 to Subpart I of Part 98—Default Emission Factors (1-Uij) for Gas Utilization Rates (Uij) and By... Gas Utilization Rates (Uij) and By-Product Formation Rates (Bijk) for PV Manufacturing I Table I-7...

  15. 40 CFR Table I-6 to Subpart I of... - Default Emission Factors (1-Uij) for Gas Utilization Rates (Uij) and By-Product Formation Rates...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Electronics Manufacturing Pt. 98, Subpt. I, Table I-6 Table I-6 to Subpart I of Part 98—Default Emission Factors (1-Uij) for Gas Utilization Rates (Uij) and By... Gas Utilization Rates (Uij) and By-Product Formation Rates (Bijk) for LCD Manufacturing I Table I-6...

  16. 40 CFR Table I-6 to Subpart I of... - Default Emission Factors (1-Uij) for Gas Utilization Rates (Uij) and By-Product Formation Rates...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Electronics Manufacturing Pt. 98, Subpt. I, Table I-6 Table I-6 to Subpart I of Part 98—Default Emission Factors (1-Uij) for Gas Utilization Rates (Uij) and By... Gas Utilization Rates (Uij) and By-Product Formation Rates(Bijk) for LCD Manufacturing I Table I-6...

  17. 40 CFR Table I-7 to Subpart I of... - Default Emission Factors (1-Uij) for Gas Utilization Rates (Uij) and By-Product Formation Rates...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Electronics Manufacturing Pt. 98, Subpt. I, Table I-7 Table I-7 to Subpart I of Part 98—Default Emission Factors (1-Uij) for Gas Utilization Rates (Uij) and By... Gas Utilization Rates (Uij) and By-Product Formation Rates (Bijk) for PV Manufacturing I Table I-7...

  18. Rate-pressure product and myocardial oxygen consumption during surgery for coronary artery bypass.

    PubMed

    Wilkinson, P L; Moyers, J R; Ports, T; Chatterjee, K; Ullyott, D; Hamilton, W K

    1979-08-01

    Rate-pressure product (RPP) is a sensitive index of myocardial oxygen consumption (mVO2) in awake people. We wished to determine whether this relationship persisted under anesthesia and in the face of concurrent large changes in myocardial contractility and left ventricular filling pressures. In 16 patients scheduled for coronary artery bypass surgery, we inserted coronary sinus and Swan-Ganz catheters, and a central aortic catheter via the brachial artery, before induction of anesthesia with either morphine (2 mg/kg) or halothane, chosen in random order. We measured aortic, pulmonary, and venous pressures, cardiac output, systolic time intervals, and thermodilution coronary sinus flow. We calculated mVO2 as coronary sinus flow times myocardial arteriovenous oxygen content difference. We found significant correlations between mVO2 and heart rate (r = 0.57), systolic blood pressure (r = 0.52), the index delta /delta T (r = 0.53, and RPP (r = 0.78). Multiple regression of RPP and delta P/delta T against mVO2 increased their correlation (r = 0.86), while multiple regression of RPP and pulmonary wedge pressure against mVo2 did not significantly improve the correlation of RPP alone (r = 0.75). We conclude that hemodynamic changes anesthesia and surgery do not decrease the sensitivity of RPP as an index of mVO2. PMID:312708

  19. Estimating oxygen consumption from heart rate using adaptive neuro-fuzzy inference system and analytical approaches.

    PubMed

    Kolus, Ahmet; Dubé, Philippe-Antoine; Imbeau, Daniel; Labib, Richard; Dubeau, Denise

    2014-11-01

    In new approaches based on adaptive neuro-fuzzy systems (ANFIS) and analytical method, heart rate (HR) measurements were used to estimate oxygen consumption (VO2). Thirty-five participants performed Meyer and Flenghi's step-test (eight of which performed regeneration release work), during which heart rate and oxygen consumption were measured. Two individualized models and a General ANFIS model that does not require individual calibration were developed. Results indicated the superior precision achieved with individualized ANFIS modelling (RMSE = 1.0 and 2.8 ml/kg min in laboratory and field, respectively). The analytical model outperformed the traditional linear calibration and Flex-HR methods with field data. The General ANFIS model's estimates of VO2 were not significantly different from actual field VO2 measurements (RMSE = 3.5 ml/kg min). With its ease of use and low implementation cost, the General ANFIS model shows potential to replace any of the traditional individualized methods for VO2 estimation from HR data collected in the field. PMID:24793823

  20. Utilizing in Situ Electrochemical SHINERS for Oxygen Reduction Reaction Studies in Aprotic Electrolytes.

    PubMed

    Galloway, Thomas A; Hardwick, Laurence J

    2016-06-01

    Spectroscopic detection of reaction intermediates upon a variety of electrode surfaces is of major interest within physical chemistry. A notable technique in the study of the electrochemical interface has been surface-enhanced Raman spectroscopy (SERS). The drawback of SERS is that it is limited to roughened gold and silver substrates. Herein we report that shell-isolated nanoparticles for enhanced Raman spectroscopy (SHINERS) can overcome the limitations of SERS and has followed the oxygen reduction reaction (ORR), within a nonaqueous electrolyte, on glassy carbon, gold, palladium, and platinum disk electrodes. The work presented demonstrates SHINERS for spectroelectrochemical studies for applied and fundamental electrochemistry in aprotic electrolytes, especially for the understanding and development of future metal-oxygen battery applications. In particular, we highlight that with the addition of Li(+), both the electrode surface and solvent influence the ORR mechanism, which opens up the possibility of tailoring surfaces to produce desired reaction pathways. PMID:27195529

  1. Utilization of Hyperbaric Oxygen Therapy and Induced Hypothermia After Hydrogen Sulfide Exposure

    PubMed Central

    Asif, Mir J.; Exline, Matthew C.

    2013-01-01

    Hydrogen sulfide is a toxic gas produced as a byproduct of organic waste and many industrial processes. Hydrogen sulfide exposure symptoms may vary from mild (dizziness, headaches, nausea) to severe lactic acidosis via its inhibition of oxidative phosphorylation, leading to cardiac arrhythmias and death. Treatment is generally supportive. We report the case of a patient presenting with cardiac arrest secondary to hydrogen sulfide exposure treated with both hyperbaric oxygen therapy and therapeutic hypothermia with great improvement in neurologic function. PMID:22004989

  2. Temperature and Atomic Oxygen Effects on Helium Leak Rates of a Candidate Main Interface Seal

    NASA Technical Reports Server (NTRS)

    Penney, Nicholas; Wasowski, Janice L.; Daniels, Christopher C.

    2011-01-01

    Helium leak tests were completed to characterize the leak rate of a 54 in. diameter composite space docking seal design in support of the National Aeronautics and Space Administration s (NASA's) Low Impact Docking System (LIDS). The evaluated seal design was a candidate for the main interface seal on the LIDS, which would be compressed between two vehicles, while docked, to prevent the escape of breathable air from the vehicles and into the vacuum of space. Leak tests completed at nominal temperatures of -30, 20, and 50 C on untreated and atomic oxygen (AO) exposed test samples were examined to determine the influence of both test temperature and AO exposure on the performance of the composite seal assembly. Results obtained for untreated seal samples showed leak rates which increased with increased test temperature. This general trend was not observed in tests of the AO exposed specimens. Initial examination of collected test data suggested that AO exposure resulted in higher helium leak rates, however, further analysis showed that the differences observed in the 20 and 50 C tests between the untreated and AO exposed samples were within the experimental error of the test method. Lack of discernable trends in the test data prevented concrete conclusions about the effects of test temperature and AO exposure on helium leak rates of the candidate seal design from being drawn. To facilitate a comparison of the current test data with results from previous leak tests using air as the test fluid, helium leak rates were converted to air leak rates using standard conversion factors for viscous and molecular flow. Flow rates calculated using the viscous flow conversion factor were significantly higher than the experimental air leakage values, whereas values calculated using the molecular flow conversion factor were significantly lower than the experimentally obtained air leak rates. The difference in these sets of converted flow rates and their deviation from the

  3. Non-homogeneous hybrid rocket fuel for enhanced regression rates utilizing partial entrainment

    NASA Astrophysics Data System (ADS)

    Boronowsky, Kenny

    A concept was developed and tested to enhance the performance and regression rate of hydroxyl terminated polybutadiene (HTPB), a commonly used hybrid rocket fuel. By adding small nodules of paraffin into the HTPB fuel, a non-homogeneous mixture was created resulting in increased regression rates. The goal was to develop a fuel with a simplified single core geometry and a tailorable regression rate. The new fuel would benefit from the structural stability of HTPB yet not suffer from the large void fraction representative of typical HTPB core geometries. Regression rates were compared between traditional HTPB single core grains, 85% HTPB mixed with 15% (by weight) paraffin cores, 70% HTPB mixed with 30% paraffin cores, and plain paraffin single core grains. Each fuel combination was tested at oxidizer flow rates, ranging from 0.9 - 3.3 g/s of gaseous oxygen, in a small scale hybrid test rocket and average regression rates were measured. While large uncertainties were present in the experimental setup, the overall data showed that the regression rate was enhanced as paraffin concentration increased. While further testing would be required at larger scales of interest, the trends are encouraging. Inclusion of paraffin nodules in the HTPB grain may produce a greater advantage than other more noxious additives in current use. In addition, it may lead to safer rocket motors with higher integrated thrust due to the decreased void fraction.

  4. Brain metabolism in autism. Resting cerebral glucose utilization rates as measured with positron emission tomography

    SciTech Connect

    Rumsey, J.M.; Duara, R.; Grady, C.; Rapoport, J.L.; Margolin, R.A.; Rapoport, S.I.; Cutler, N.R.

    1985-05-01

    The cerebral metabolic rate for glucose was studied in ten men (mean age = 26 years) with well-documented histories of infantile autism and in 15 age-matched normal male controls using positron emission tomography and (F-18) 2-fluoro-2-deoxy-D-glucose. Positron emission tomography was completed during rest, with reduced visual and auditory stimulation. While the autistic group as a whole showed significantly elevated glucose utilization in widespread regions of the brain, there was considerable overlap between the two groups. No brain region showed a reduced metabolic rate in the autistic group. Significantly more autistic, as compared with control, subjects showed extreme relative metabolic rates (ratios of regional metabolic rates to whole brain rates and asymmetries) in one or more brain regions.

  5. Towards More Transmission Asset Utilization through Real-time Path Rating

    SciTech Connect

    Diao, Ruisheng; Huang, Zhenyu; Jin, Chunlian; Vyakaranam, Bharat GNVSR; Jin, Shuangshuang; Makarov, Yuri V.

    2013-10-21

    Ratings of transmission paths, typically determined in an offline environment, are static and tend to be conservative, leading to underutilization of transmission assets, higher costs of system operation and renewable energy integration, and lower efficiency and savings. With the ever-increasing transmission congestion costs and new challenges from renewable integration, increasing transfer capacity of existing transmission lines is essential. Real-time path rating provides a promising approach to enabling additional power transfer capability and fully utilizing transfer capability. In this paper, the feasibility of real-time path rating is investigated. Several promising technologies to achieve real-time path rating are discussed. Various benefits that can be expected from real-time path rating, such as increased transfer capability and reduced total generation cost, are demonstrated through simulations conducted on the Western Electricity Coordinating Council system model.

  6. The effect of submergence on heart rate and oxygen consumption of swimming seals and sea lions.

    PubMed

    Williams, T M; Kooyman, G L; Croll, D A

    1991-01-01

    Respiratory, metabolic, and cardiovascular responses to swimming were examined in two species of pinniped, the harbor seal (Phoca vitulina) and the California sea lion (Zalophus californianus). 1. Harbor seals remained submerged for 82-92% of the time at swimming speeds below 1.2 m.s-1. At higher speeds, including simulated speeds above 1.4 m.s-1, the percentage of time spent submerged decreased, and was inversely related to body weight. In contrast, the percentage of time spent submerged did not change with speed for sea lions swimming from 0.5 m.s-1 to 4.0 m.s-1. 2. During swimming, harbor seals showed a distinct breathhold bradycardia and ventilatory tachycardia that were independent of swimming speed. Average heart rate was 137 beats.min-1 when swimming on the water surface and 50 beats.min-1 when submerged. A bimodal pattern of heart rate also occurred in sea lions, but was not as pronounced as in the seals. 3. The weighted average heart rate (WAHR), calculated from measured heart rate and the percentage time spent on the water surface or submerged, increased linearly with swimming speed for both species. The graded increase in heart rate with exercise load is similar to the response observed for terrestrial mammals. 4. The rate of oxygen consumption increased exponentially with swimming speed in both seals and sea lions. The minimum cost of transport calculated from these rates ranged from 2.3 to 3.6 J.m-1.kg-1, and was 2.5-4.0 times the level predicted for similarly-sized salmonids. Despite different modes of propulsion and physiological responses to swimming, these pinnipeds demonstrate similar transport costs. PMID:2045544

  7. Global rate coefficients for ionization and recombination of carbon, nitrogen, oxygen, and argon

    SciTech Connect

    Annaloro, Julien; Morel, Vincent; Bultel, Arnaud; Omaly, Pierre

    2012-07-15

    The flow field modeling of planetary entry plasmas, laser-induced plasmas, inductively coupled plasmas, arcjets, etc., requires to use Navier-Stokes codes. The kinetic mechanisms implemented in these codes involve global (effective) rate coefficients. These rate coefficients result from the excited states coupling during a quasi-steady state. In order to obtain these global rate coefficients over a wide electron temperature (T{sub e}) range for ionization and recombination of carbon, nitrogen, oxygen, and argon, the behavior of their excited states is investigated using a zero-dimensional (time-dependent) code. The population number densities of these electronic states are considered as independent species. Their relaxation is studied within the range 3000 K{<=}T{sub e}{<=}20 000 K and leads to the determination of the ionization (k{sub i}) and recombination (k{sub r}) global rate coefficients. Comparisons with existing data are performed. Finally, the ratio k{sub i}/k{sub r} is compared with the Saha equilibrium constant. This ratio increases more rapidly than the equilibrium constant for T{sub e}>15 000 K.

  8. Going After Nitrate: Utilizing Oxygen Isotopes to Identify Nitrogen Cycling Mechanisms in Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrate pollution as a result of over utilization of fertilizers has recently received considerable interest because of its harmful effects on the environment. Studies have been carried out to identify sources of surface/ground-water nitrate through the use of dual isotope analysis, d15N and d18O. H...

  9. Design a Wearable Device for Blood Oxygen Concentration and Temporal Heart Beat Rate

    NASA Astrophysics Data System (ADS)

    Myint, Cho Zin; Barsoum, Nader; Ing, Wong Kiing

    2010-06-01

    The wireless network technology is increasingly important in healthcare as a result of the aging population and the tendency to acquire chronic disease such as heart attack, high blood pressure amongst the elderly. A wireless sensor network system that has the capability to monitor physiological sign such as SpO2 (Saturation of Arterial Oxygen) and heart beat rate in real-time from the human's body is highlighted in this study. This research is to design a prototype sensor network hardware, which consists of microcontroller PIC18F series and transceiver unit. The sensor is corporate into a wearable body sensor network which is small in size and easy to use. The sensor allows a non invasive, real time method to provide information regarding the health of the body. This enables a more efficient and economical means for managing the health care of the population.

  10. Preliminary energy sector assessments of Jamaica. Volume V: electric utility rate analysis

    SciTech Connect

    Not Available

    1980-01-01

    The study analyzes the electric utility rate structure of the Jamaica Public Service Company (JPS) in order to determine whether it promotes economically efficient use of electricity, is based on principles of equity and fairness, and provides JPS with sufficient resources to maintain acceptable service quality. Current tariffs are described, and features such as declining block tariffs (decreasing unit price with increasing volume used), expander clauses (decreasing rate if total energy use increases without increasing maximum power demand), and ratchet clauses (little or no reduction in charges if use falls below a previously set high), which may not encourage conservation or efficient system usage, are noted. Various tariff options, based on marginal cost pricing principles (tying prices to the additional cost of supplying the electricity), are presented for each rate category in the JPS system (residential, small commercial, industrial, and large commercial). Flat rate (with and without demand charges), time of use pricing, fuel adjustment, and cost of service adjustment are considered.

  11. Speed over efficiency: locusts select body temperatures that favour growth rate over efficient nutrient utilization.

    PubMed

    Miller, Gabriel A; Clissold, Fiona J; Mayntz, David; Simpson, Stephen J

    2009-10-22

    Ectotherms have evolved preferences for particular body temperatures, but the nutritional and life-history consequences of such temperature preferences are not well understood. We measured thermal preferences in Locusta migratoria (migratory locusts) and used a multi-factorial experimental design to investigate relationships between growth/development and macronutrient utilization (conversion of ingesta to body mass) as a function of temperature. A range of macronutrient intake values for insects at 26, 32 and 38 degrees C was achieved by offering individuals high-protein diets, high-carbohydrate diets or a choice between both. Locusts placed in a thermal gradient selected temperatures near 38 degrees C, maximizing rates of weight gain; however, this enhanced growth rate came at the cost of poor protein and carbohydrate utilization. Protein and carbohydrate were equally digested across temperature treatments, but once digested both macronutrients were converted to growth most efficiently at the intermediate temperature (32 degrees C). Body temperature preference thus yielded maximal growth rates at the expense of efficient nutrient utilization. PMID:19625322

  12. Myocardial blood flow and its transit time, oxygen utilization, and efficiency of highly endurance-trained human heart.

    PubMed

    Heinonen, Ilkka; Kudomi, Nobuyuki; Kemppainen, Jukka; Kiviniemi, Antti; Noponen, Tommi; Luotolahti, Matti; Luoto, Pauliina; Oikonen, Vesa; Sipilä, Hannu T; Kopra, Jaakko; Mononen, Ilkka; Duncker, Dirk J; Knuuti, Juhani; Kalliokoski, Kari K

    2014-07-01

    Highly endurance-trained athlete's heart represents the most extreme form of cardiac adaptation to physical stress, but its circulatory alterations remain obscure. In the present study, myocardial blood flow (MBF), blood mean transit time (MTT), oxygen extraction fraction (OEF) and consumption (MVO2), and efficiency of cardiac work were quantified in highly trained male endurance athletes and control subjects at rest and during supine cycling exercise using [(15)O]-labeled radiotracers and positron emission tomography. Heart rate and MBF were lower in athletes both at rest and during exercise. OEF increased in response to exercise in both groups, but was higher in athletes (70 ± 21 vs. 63 ± 11 % at rest and 86 ± 13 vs. 73 ± 10 % during exercise). MTT was longer and vascular resistance higher in athletes both at rest and during exercise, but arterial content of 2,3-diphosphoglycerate (oxygen affinity) was unchanged. MVO2 per gram of myocardium trended (p = 0.08) lower in athletes both at rest and during exercise, while myocardial efficiency of work and MVO2 per beat were not different between groups. Arterial levels of free fatty acids were ~twofold higher in athletes likely leading to higher myocardial fatty acid oxidation and hence oxygen cost, which may have blunted the bradycardia-induced decrease in MVO2. Finally, the observed group differences in MBF, OEF, MTT and vascular resistance remained significant also after they were controlled for differences in MVO2. In conclusion, in highly endurance-trained human heart, increased myocardial blood transition time enables higher oxygen extraction levels with a lower myocardial blood flow and higher vascular resistance. These physiological adaptations to exercise training occur independently of the level of oxygen consumption and together with training-induced bradycardia may serve as mechanisms to increase functional reserve of the human heart. PMID:24866583

  13. Direct measurement of oxygen consumption rates from attached and unattached cells in a reversibly sealed, diffusionally isolated sample chamber

    PubMed Central

    Strovas, Timothy J.; McQuaide, Sarah C.; Anderson, Judy B.; Nandakumar, Vivek; Kalyuzhnaya, Marina G.; Burgess, Lloyd W.; Holl, Mark R.; Meldrum, Deirdre R.; Lidstrom, Mary E.

    2011-01-01

    Oxygen consumption is a fundamental component of metabolic networks, mitochondrial function, and global carbon cycling. To date there is no method available that allows for replicate measurements on attached and unattached biological samples without compensation for extraneous oxygen leaking into the system. Here we present the Respiratory Detection System, which is compatible with virtually any biological sample. The RDS can be used to measure oxygen uptake in microliter-scale volumes with a reversibly sealed sample chamber, which contains a porphyrin-based oxygen sensor. With the RDS, one can maintain a diffusional seal for up to three hours, allowing for the direct measurement of respiratory function of samples with fast or slow metabolic rates. The ability to easily measure oxygen uptake in small volumes with small populations or dilute samples has implications in cell biology, environmental biology, and clinical diagnostics. PMID:21546993

  14. THE PRIMARY STARCH UTILIZATION OPERON IN THE OBLIGATE ANAEROBE BACTEROIDES FRAGILIS IS REGULATED BY CARBON SOURCE AND OXYGEN, AND EXPRESSION IS IMPORTANT FOR SURVIVAL DURING OXIDATIVE STRESS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The obligate anaerobe Bacteroides fragilis is a commensal organism of the human large intestine where it utilizes both dietary and host-derived polysaccharides as a source of carbon and energy. This study describes the characterization of a novel operon, designated oxygen-induced starch utilization...

  15. Low effective activation energies for oxygen release from metal oxides: evidence for mass-transfer limits at high heating rates.

    PubMed

    Jian, Guoqiang; Zhou, Lei; Piekiel, Nicholas W; Zachariah, Michael R

    2014-06-01

    Oxygen release from metal oxides at high temperatures is relevant to many thermally activated chemical processes, including chemical-looping combustion, solar thermochemical cycles and energetic thermite reactions. In this study, we evaluated the thermal decomposition of nanosized metal oxides under rapid heating (~10(5) K s(-1)) with time-resolved mass spectrometry. We found that the effective activation-energy values that were obtained using the Flynn-Wall-Ozawa isoconversional method are much lower than the values found at low heating rates, indicating that oxygen transport might be rate-determining at a high heating rate. PMID:24619858

  16. Species-level variability in extracellular production rates of reactive oxygen species by diatoms

    NASA Astrophysics Data System (ADS)

    Schneider, Robin; Roe, Kelly; Hansel, Colleen; Voelker, Bettina

    2016-03-01

    Biological production and decay of the reactive oxygen species (ROS) hydrogen peroxide (H2O2) and superoxide (O2-) likely have significant effects on the cycling of trace metals and carbon in marine systems. In this study, extracellular production rates of H2O2 and O2- were determined for five species of marine diatoms in the presence and absence of light. Production of both ROS was measured in parallel by suspending cells on filters and measuring the ROS downstream using chemiluminescence probes. In addition, the ability of these organisms to break down O2- and H2O2 was examined by measuring recovery of O2- and H2O2 added to the influent medium. O2- production rates ranged from undetectable to 7.3 x 10-16 mol cell-1 hr-1, while H2O2 production rates ranged from undetectable to 3.4 x 10-16 mol cell-1 hr-1. Results suggest that extracellular ROS production occurs through a variety of pathways even amongst organisms of the same genus. Thalassiosira spp. produced more O2- in light than dark, even when the organisms were killed, indicating that O2- is produced via a passive photochemical process on the cell surface. The ratio of H2O¬2 to O2- production rates was consistent with production of H2O2 solely through dismutation of O2- for T. oceanica, while T. pseudonana made much more H2O2 than O2 . T. weissflogii only produced H2O2 when stressed or killed. P. tricornutum cells did not make cell-associated ROS, but did secrete H2O2-producing substances into the growth medium. In all organisms, recovery rates for killed cultures (94-100% H2O2; 10-80% O2-) were consistently higher than those for live cultures (65-95% H2O2; 10-50% O2-). While recovery rates for killed cultures in H2O2 indicate that nearly all H2O2 was degraded by active cell processes, O2- decay appeared to occur via a combination of active and passive processes. Overall, this study shows that the rates and pathways for ROS production and decay vary greatly among diatom species, even between those that are

  17. Species-Level Variability in Extracellular Production Rates of Reactive Oxygen Species by Diatoms

    PubMed Central

    Schneider, Robin J.; Roe, Kelly L.; Hansel, Colleen M.; Voelker, Bettina M.

    2016-01-01

    Biological production and decay of the reactive oxygen species (ROS) hydrogen peroxide (H2O2) and superoxide (O2-) likely have significant effects on the cycling of trace metals and carbon in marine systems. In this study, extracellular production rates of H2O2 and O2- were determined for five species of marine diatoms in the presence and absence of light. Production of both ROS was measured in parallel by suspending cells on filters and measuring the ROS downstream using chemiluminescence probes. In addition, the ability of these organisms to break down O2- and H2O2 was examined by measuring recovery of O2- and H2O2 added to the influent medium. O2- production rates ranged from undetectable to 7.3 × 10−16 mol cell−1 h−1, while H2O2 production rates ranged from undetectable to 3.4 × 10−16 mol cell−1 h−1. Results suggest that extracellular ROS production occurs through a variety of pathways even amongst organisms of the same genus. Thalassiosira spp. produced more O2- in light than dark, even when the organisms were killed, indicating that O2- is produced via a passive photochemical process on the cell surface. The ratio of H2O2 to O2- production rates was consistent with production of H2O2 solely through dismutation of O2- for T. oceanica, while T. pseudonana made much more H2O2 than O2-. T. weissflogii only produced H2O2 when stressed or killed. P. tricornutum cells did not make cell-associated ROS, but did secrete H2O2-producing substances into the growth medium. In all organisms, recovery rates for killed cultures (94–100% H2O2; 10–80% O2-) were consistently higher than those for live cultures (65–95% H2O2; 10–50% O2-). While recovery rates for killed cultures in H2O2 indicate that nearly all H2O2 was degraded by active cell processes, O2- decay appeared to occur via a combination of active and passive processes. Overall, this study shows that the rates and pathways for ROS production and decay vary greatly among diatom species, even

  18. Species-Level Variability in Extracellular Production Rates of Reactive Oxygen Species by Diatoms.

    PubMed

    Schneider, Robin J; Roe, Kelly L; Hansel, Colleen M; Voelker, Bettina M

    2016-01-01

    Biological production and decay of the reactive oxygen species (ROS) hydrogen peroxide (H2O2) and superoxide (O[Formula: see text]) likely have significant effects on the cycling of trace metals and carbon in marine systems. In this study, extracellular production rates of H2O2 and O[Formula: see text] were determined for five species of marine diatoms in the presence and absence of light. Production of both ROS was measured in parallel by suspending cells on filters and measuring the ROS downstream using chemiluminescence probes. In addition, the ability of these organisms to break down O[Formula: see text] and H2O2 was examined by measuring recovery of O[Formula: see text] and H2O2 added to the influent medium. O[Formula: see text] production rates ranged from undetectable to 7.3 × 10(-16) mol cell(-1) h(-1), while H2O2 production rates ranged from undetectable to 3.4 × 10(-16) mol cell(-1) h(-1). Results suggest that extracellular ROS production occurs through a variety of pathways even amongst organisms of the same genus. Thalassiosira spp. produced more O[Formula: see text] in light than dark, even when the organisms were killed, indicating that O[Formula: see text] is produced via a passive photochemical process on the cell surface. The ratio of H2O2 to O[Formula: see text] production rates was consistent with production of H2O2 solely through dismutation of O[Formula: see text] for T. oceanica, while T. pseudonana made much more H2O2 than O[Formula: see text]. T. weissflogii only produced H2O2 when stressed or killed. P. tricornutum cells did not make cell-associated ROS, but did secrete H2O2-producing substances into the growth medium. In all organisms, recovery rates for killed cultures (94-100% H2O2; 10-80% O[Formula: see text]) were consistently higher than those for live cultures (65-95% H2O2; 10-50% O[Formula: see text]). While recovery rates for killed cultures in H2O2 indicate that nearly all H2O2 was degraded by active cell processes, O

  19. Potential utility of hyperbaric oxygen therapy and propolis in enhancing the leishmanicidal activity of glucantime.

    PubMed

    Ayres, Diana Copi; Fedele, Thiago Antonio; Marcucci, Maria Cristina; Giorgio, Selma

    2011-01-01

    In this study we investigated the efficacy of hyperbaric oxygen (HBO) therapy, alone or combined with the pentavalent antimonial glucantime on Leishmania amazonensis infection. In parallel, the effect of Brazilian red propolis gel (propain) alone or combined with glucantime on L. amazonensis infection was evaluated. The inhibition of the infection in macrophages treated with glucantime in combination with HBO exposition was greater than that of macrophages treated with glucantime alone or HBO alone. The susceptible mouse strain BALB/c infected in the shaved rump with L. amazonensis treated with glucantime and exposed to HBO showed: time points in the course of the disease in which lesions were smaller than those of mice treated with glucantime alone and revascularization of the skin in the lesion site; interferon-gamma (IFN-g) levels were not elevated in lymph node cells from these animals. Propain alone was not efficient against lesions, although less exudative lesions were observed in animals treated with propain alone or combined with glucantime. These results reveal the potential value of HBO and red propolis in combination with glucantime for treating cutaneous leishmaniasis and encourage further studies on the effect of more aggressive HBO, propolis and glucantime therapies on different mouse models of leishmaniasis. PMID:22183457

  20. Utility Rate Equations of Group Population Dynamics in Biological and Social Systems

    PubMed Central

    Yukalov, Vyacheslav I.; Yukalova, Elizaveta P.; Sornette, Didier

    2013-01-01

    We present a novel system of equations to describe the evolution of self-organized structured societies (biological or human) composed of several trait groups. The suggested approach is based on the combination of ideas employed in the theory of biological populations, system theory, and utility theory. The evolution equations are defined as utility rate equations, whose parameters are characterized by the utility of each group with respect to the society as a whole and by the mutual utilities of groups with respect to each other. We analyze in detail the cases of two groups (cooperators and defectors) and of three groups (cooperators, defectors, and regulators) and find that, in a self-organized society, neither defectors nor regulators can overpass the maximal fractions of about each. This is in agreement with the data for bee and ant colonies. The classification of societies by their distance from equilibrium is proposed. We apply the formalism to rank the countries according to the introduced metric quantifying their relative stability, which depends on the cost of defectors and regulators as well as their respective population fractions. We find a remarkable concordance with more standard economic ranking based, for instance, on GDP per capita. PMID:24386163

  1. Relationship of vitamin A utilization rate to vitamin A status in the rat

    SciTech Connect

    Lewis, K.C.; Green, J.B.; Green, M.H.

    1986-03-01

    Weanling male rats were fed diets providing either 45 ..mu..g retinal equivalents (REq)/d for 4 wks, then 12 ..mu..g/d for 11 wks (HI; n = 9); or 0 ..mu..g/d for 7 wks, then 2 ..mu..g/d for 6 wks (LO; n = 8); or 0 ..mu..g/d for 7 wks, then 2 ..mu..g REq + 240 ..mu..g retinoic acid/d for 6 wks (RA; n = 6). At this time, plasma retinol (ROH) concentrations averaged 48.9 +/- 7.2, 10.3 +/- 1.7 and 8.5 +/- 0.9 ..mu..g/dl, respectively; and liver retinoid levels were 984.9 +/- 146.2, < 0.5, and < 5 ..mu..g REq. Growth rates were similar in all groups. Plasma ROH kinetics were monitored for 115 d (HI) or 35 d (LO and RA) after an IV pulse dose injection of plasma containing /sup 3/H-ROH in its physiological transport complex. Vitamin A utilization rates (disposal rates, DR) were estimated from the inverse of the area under the tracer disappearance curve obtained by nonlinear, least-squares regression. Group average DR were 12.2 (HI), 1.8 (LO), and 1.2 (RA) ..mu..g REq/d. Since in similar studies the DR was 6.9 ..mu..g/d in rats consuming approx. 9 ..mu..g REq/d, and with liver stores of approx. 73 ..mu..g, the authors data suggest that vitamin A utilization rate adjusts to stores and/or dietary input, and that rats with virtually no liver vitamin A reserves and chronically fed marginal levels of vitamin A, are able to adapt by decreasing vitamin A utilization.

  2. Non-contact estimation of heart rate and oxygen saturation using ambient light

    PubMed Central

    Bal, Ufuk

    2014-01-01

    We propose a robust method for automated computation of heart rate (HR) from digital color video recordings of the human face. In order to extract photoplethysmographic signals, two orthogonal vectors of RGB color space are used. We used a dual tree complex wavelet transform based denoising algorithm to reduce artifacts (e.g. artificial lighting, movement, etc.). Most of the previous work on skin color based HR estimation performed experiments with healthy volunteers and focused to solve motion artifacts. In addition to healthy volunteers we performed experiments with child patients in pediatric intensive care units. In order to investigate the possible factors that affect the non-contact HR monitoring in a clinical environment, we studied the relation between hemoglobin levels and HR estimation errors. Low hemoglobin causes underestimation of HR. Nevertheless, we conclude that our method can provide acceptable accuracy to estimate mean HR of patients in a clinical environment, where the measurements can be performed remotely. In addition to mean heart rate estimation, we performed experiments to estimate oxygen saturation. We observed strong correlations between our SpO2 estimations and the commercial oximeter readings PMID:25657877

  3. The utility of heart rate and minute ventilation as predictors of whole-body metabolic rate during occupational simulations involving load carriage.

    PubMed

    Notley, Sean R; Peoples, Gregory E; Taylor, Nigel A S

    2015-01-01

    The utility of cardiac and ventilatory predictors of metabolic rate derived under temperate and heated laboratory conditions was evaluated during three fire-fighting simulations (70-mm hose drag, Hazmat recovery, bushfire hose drag; N = 16 per simulation). The limits of agreement for cardiac (temperate: - 0.54 to 1.77; heated: - 1.39 to 0.80 l min(- 1)) and ventilatory surrogates (temperate: - 0.19 to 1.27; heated: - 0.26 to 1.16 l min(- 1)) revealed an over-estimation of oxygen consumption that exceeded the acceptable limits required by occupational physiologists (N = 25; ± 0.24 l min(- 1)). Although ventilatory predictions offered superior precision during low-intensity work (P < 0.05), a cardiac prediction was superior during more demanding work (P < 0.05). Deriving those equations under heated conditions failed to improve precision, with the exception of the cardiac surrogate during low-intensity work (P < 0.05). These observations imply that individualised prediction curves are necessary for valid estimations of metabolic demand in the field. PMID:25746518

  4. Oxygen consumption rate of early pre-antral follicles from vitrified human ovarian cortical tissue.

    PubMed

    Ishikawa, Takayuki; Kyoya, Toshihiko; Nakamura, Yusuke; Sato, Eimei; Tomiyama, Tatsuhiro; Kyono, Koichi

    2014-01-01

    The study of human ovarian tissue transplantation and cryopreservation has advanced significantly. Autotransplantation of human pre-antral follicles isolated from cryopreserved cortical tissue is a promising option for the preservation of fertility in young cancer patients. The purpose of the present study was to reveal the effect of vitrification after low-temperature transportation of human pre-antral follicles by using the oxygen consumption rate (OCR). Cortical tissues from 9 ovaries of female-to-male transsexuals were vitrified after transportation (6 or 18 h). The follicles were enzymatically isolated from nonvitrified tissue (group I, 18 h of transportation), vitrified-warmed tissue (group II, 6 and 18 h of transportation) and vitrified-warmed tissue that had been incubated for 24 h (group III, 6 and 18 h of transportation). OCR measurement and the LIVE/DEAD viability assay were performed. Despite the ischemic condition, the isolated pre-antral follicles in group I consumed oxygen, and the mean OCRs increased with developmental stage. Neither the transportation time nor patient age seemed to affect the OCR in this group. Meanwhile, the mean OCR was significantly lower (P < 0.05) in group II but was comparable to that of group I after 24 h of incubation. The integrity of vitrified-warmed primordial and primary follicles was clearly corroborated by the LIVE/DEAD viability assay. These results demonstrate that the OCR can be used to directly estimate the effect of vitrification on the viability of primordial and primary follicles and to select the viable primordial and primary follicles from vitrified-warmed follicles. PMID:25262776

  5. Oxygen consumption rate of early pre-antral follicles from vitrified human ovarian cortical tissue

    PubMed Central

    ISHIKAWA, Takayuki; KYOYA, Toshihiko; NAKAMURA, Yusuke; SATO, Eimei; TOMIYAMA, Tatsuhiro; KYONO, Koichi

    2014-01-01

    The study of human ovarian tissue transplantation and cryopreservation has advanced significantly. Autotransplantation of human pre-antral follicles isolated from cryopreserved cortical tissue is a promising option for the preservation of fertility in young cancer patients. The purpose of the present study was to reveal the effect of vitrification after low-temperature transportation of human pre-antral follicles by using the oxygen consumption rate (OCR). Cortical tissues from 9 ovaries of female-to-male transsexuals were vitrified after transportation (6 or 18 h). The follicles were enzymatically isolated from nonvitrified tissue (group I, 18 h of transportation), vitrified-warmed tissue (group II, 6 and 18 h of transportation) and vitrified-warmed tissue that had been incubated for 24 h (group III, 6 and 18 h of transportation). OCR measurement and the LIVE/DEAD viability assay were performed. Despite the ischemic condition, the isolated pre-antral follicles in group I consumed oxygen, and the mean OCRs increased with developmental stage. Neither the transportation time nor patient age seemed to affect the OCR in this group. Meanwhile, the mean OCR was significantly lower (P < 0.05) in group II but was comparable to that of group I after 24 h of incubation. The integrity of vitrified-warmed primordial and primary follicles was clearly corroborated by the LIVE/DEAD viability assay. These results demonstrate that the OCR can be used to directly estimate the effect of vitrification on the viability of primordial and primary follicles and to select the viable primordial and primary follicles from vitrified-warmed follicles. PMID:25262776

  6. Muscle oxygen transport and utilization in heart failure: implications for exercise (in)tolerance

    PubMed Central

    Hirai, Daniel M.; Copp, Steven W.; Musch, Timothy I.

    2012-01-01

    The defining characteristic of chronic heart failure (CHF) is an exercise intolerance that is inextricably linked to structural and functional aberrations in the O2 transport pathway. CHF reduces muscle O2 supply while simultaneously increasing O2 demands. CHF severity varies from moderate to severe and is assessed commonly in terms of the maximum O2 uptake, which relates closely to patient morbidity and mortality in CHF and forms the basis for Weber and colleagues' (167) classifications of heart failure, speed of the O2 uptake kinetics following exercise onset and during recovery, and the capacity to perform submaximal exercise. As the heart fails, cardiovascular regulation shifts from controlling cardiac output as a means for supplying the oxidative energetic needs of exercising skeletal muscle and other organs to preventing catastrophic swings in blood pressure. This shift is mediated by a complex array of events that include altered reflex and humoral control of the circulation, required to prevent the skeletal muscle “sleeping giant” from outstripping the pathologically limited cardiac output and secondarily impacts lung (and respiratory muscle), vascular, and locomotory muscle function. Recently, interest has also focused on the dysregulation of inflammatory mediators including tumor necrosis factor-α and interleukin-1β as well as reactive oxygen species as mediators of systemic and muscle dysfunction. This brief review focuses on skeletal muscle to address the mechanistic bases for the reduced maximum O2 uptake, slowed O2 uptake kinetics, and exercise intolerance in CHF. Experimental evidence in humans and animal models of CHF unveils the microvascular cause(s) and consequences of the O2 supply (decreased)/O2 demand (increased) imbalance emblematic of CHF. Therapeutic strategies to improve muscle microvascular and oxidative function (e.g., exercise training and anti-inflammatory, antioxidant strategies, in particular) and hence patient exercise

  7. Triiodothyronine Facilitates Weaning From Extracorporeal Membrane Oxygenation by Improved Mitochondrial Substrate Utilization

    PubMed Central

    Files, Matthew D.; Kajimoto, Masaki; O'Kelly Priddy, Colleen M.; Ledee, Dolena R.; Xu, Chun; Des Rosiers, Christine; Isern, Nancy; Portman, Michael A.

    2014-01-01

    Background Extracorporeal membrane oxygenation (ECMO) provides a bridge to recovery after myocardial injury in infants and children, yet morbidity and mortality remain high. Weaning from the circuit requires adequate cardiac contractile function, which can be impaired by metabolic disturbances induced either by ischemia‐reperfusion and/or by ECMO. We tested the hypothesis that although ECMO partially ameliorates metabolic abnormalities induced by ischemia‐reperfusion, these abnormalities persist or recur with weaning. We also determined if thyroid hormone supplementation (triiodothyronine) during ECMO improves oxidative metabolism and cardiac function. Methods and Results Neonatal piglets underwent transient coronary ischemia to induce cardiac injury then were separated into 4 groups based on loading status. Piglets without coronary ischemia served as controls. We infused into the left coronary artery [2‐13C]pyruvate and [13C6, 15N]l‐leucine to evaluate oxidative metabolism by gas chromatography‐mass spectroscopy and nuclear magnetic resonance methods. ECMO improved survival, increased oxidative substrate contribution through pyruvate dehydrogenase, reduced succinate and fumarate accumulation, and ameliorated ATP depletion induced by ischemia. The functional and metabolic benefit of ECMO was lost with weaning, yet triiodothyronine supplementation during ECMO restored function, increased relative pyruvate dehydrogenase flux, reduced succinate and fumarate, and preserved ATP stores. Conclusions Although ECMO provides metabolic rest by decreasing energy demand, metabolic impairments persist, and are exacerbated with weaning. Treating ECMO‐induced thyroid depression with triiodothyronine improves substrate flux, myocardial oxidative capacity and cardiac contractile function. This translational model suggests that metabolic targeting can improve weaning. PMID:24650924

  8. Oxygen isotope fractionation in travertine-depositing pools at Baishuitai, Yunnan, SW China: Effects of deposition rates

    NASA Astrophysics Data System (ADS)

    Sun, Hailong; Liu, Zaihua; Yan, Hao

    2014-05-01

    Travertine δ18O values can be used to reconstruct paleo-temperatures if the oxygen isotope fractionation factors between travertine and water are accurately understood. For this purpose, the δ18O values of pool travertine and its parent water, and the deposition rates of the calcite were investigated at Baishuitai (Yunnan, SW China) over the course of the full hydrological year, April 23 2006-April 25 2007. The results show that the travertine-water isotope fractionation factors are close to the commonly accepted equilibrium line of Kim and O'Neil (1997). This differs from the results obtained by Yan et al. (2012) who found that the oxygen isotope fractionation factors in the travertine-depositing pools were close to the line suggested as equilibrium relationship by Coplen (2007). The average calcite deposition rate (2.30 mg cm-2 d-1) in the present study is six times larger than that (0.38 mg cm-2 d-1) in Yan et al. (2012). If slower calcite precipitation leads to equilibrium oxygen isotopic fractionation, then the results of this study support the results of Coplen (2007) that indicate that the equilibrium fractionation factor may be greater than the commonly accepted one derived by Kim and O'Neil (1997). The relationship between oxygen isotope fractionation factor and calcite deposition rate in our study also agrees with the results of Dietzel et al. (2009) who found that the kinetic-isotope effect favors preferential incorporation of 16O in solid calcite as the calcite deposition rate increases. There was a threshold for calcite precipitation rate control on oxygen isotopic equilibrium. In our case of travertine-depositing pools, when the calcite deposition rate was lower than 0.38 mg cm-2 d-1, oxygen isotopic equilibrium between calcite and water was attained. Therefore, calcite deposition rate is a potentially important consideration when using δ18O in natural carbonates as a proxy for terrestrial and ocean temperature.

  9. Effect of gender on glucose utilization rates in healthy humans: A positron emission tomography study

    SciTech Connect

    Miura, S.A.; Schapiro, M.B.; Grady, C.L.; Kumar, A.; Salerno, J.A.; Kozachuk, W.E.; Wagner, E.; Rapoport, S.I.; Horwitz, B. )

    1990-12-01

    Positron emission tomography (PET) was used with 18fluorodeoxyglucose to see if gender differences in resting cerebral glucose utilization could be detected. Thirty-two healthy subjects (15 women and 17 men; age range: 21-38 yr) were examined using a high-resolution PET scanner to determine the regional cerebral metabolic rate for glucose (CMRglc) in 65 gray matter regions of interest. Whole brain CMRglc did not differ significantly between the two genders, nor did any of the regional CMRglc values. Only 1 of 65 ratios of regional-to-whole brain CMRglc differed significantly between men and women, which is consistent with chance. These results indicate that there are no differences in resting regional cerebral glucose utilization between young men and women.

  10. Influence of methanol/sorbitol co-feeding rate on pAOX1 induction in a Pichia pastoris Mut+ strain in bioreactor with limited oxygen transfer rate.

    PubMed

    Carly, F; Niu, H; Delvigne, F; Fickers, P

    2016-04-01

    High Pichia pastoris biomass density could be obtained using high co-feeding rate of methanol and sorbitol in a fed-batch or continuous culture, while further higher feeding rate finally leads to oxygen limitation in bioreactor. In the literature, there is lack of report about AOX1 promoter regulation with regard to dissolved oxygen level (DO). Therefore, in this work, chemostat cultures were performed to investigate the cell growth, metabolism and regulation of the AOX1 promoter (pAOX1) regarding co-feeding rate of optimized methanol/sorbitol mixture (methanol fraction 0.60 C-mol/C-mol) using a P. pastoris Mut+/pAOX1-lacZ strain. The oxygen transfer rates (OTR) in bioreactor were kept in the range of typical values of large bioreactor, i.e., 4-8 g/(L h) if DO equals 30 % saturation or 5-10 g/(L h) if DO nears zero. For DO >0, an increase of the carbon fed led to an increase of pAOX1 induction. By contrast, when dissolved oxygen was completely depleted, methanol accumulated, causing a 30 % decrease of pAOX1 induction. However, this decrease is more likely to be lined to methanol accumulation than to low level of dissolved oxygen (<4 % DO). Methanol/sorbitol co-feeding allowed cells to adapt to oxygen transient limitations that often occur at industrial scale with reduced effect on pAOX1 induction. The optimal feeding rate tested here was 6.6 mmol C (DCW h)(-1) at an OTR of 8.28 g O2(L h)(-1) with over fivefold pAOX1 induction (probably directly associated with target protein productivity) compared with previous work. PMID:26790417

  11. Public Utility Regulatory Policies Act of 1978: Natural Gas Rate Design Study

    SciTech Connect

    None,

    1980-05-01

    The report concludes that, to effectively deal with our national energy problems, gas rate structures should be designed to reflect the costs which the nation avoids if gas is efficiently used and substituted for oil. Current pipeline and distribution company rate structures generally do not meet this test. Although gas is a substitute for oil in many applications, and conserved gas can reduce oil imports, gas rate structures often fail to convey to consumers the fact that, from a national perspective, gas is as valuable as oil. The provisions of the Natural Gas Policy Act of 1978 (NGPA) take a strong first step in correcting these problems. But, as clearly recognized in both NGPA and PURPA, these provisions need to be supplemented by updating pipeline and distribution company rate designs to address the problems of the 1980's - rather than the problems of the 1950's. In this regard, NGPA mandates incremental pricing, which raises the average price of gas to certain industrial users only. The Department of Energy (DOE) study suggests an alternate approach: pipeline and distribution rate structures that reflect in their tailblocks, for all customer classes, the economic costs of gas usage. Such rates would convey to all users the costs incurred by the nation as a consequence of their decisions to use or conserve gas. Such rate structures should promote the three purposes of PURPA - end-use conservation, efficient use of utility resources, and equitable rates - to a greater extent than do traditional accounting cost rate designs, which reflect decisions made in the distant past.

  12. 78 FR 28583 - Utility Bid USA, LLC: Supplemental Notice That Initial Market-Based Rate Filing Includes Request...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-15

    ... Energy Regulatory Commission Utility Bid USA, LLC: Supplemental Notice That Initial Market- Based Rate...-referenced proceeding, of Utility Bid USA, LLC's application for market-based rate authority, with an..., please email FERCOnlineSupport@ferc.gov . or call (866) 208-3676 (toll free). For TTY, call (202)...

  13. Process for the oxidation of materials in water at supercritical temperatures utilizing reaction rate enhancers

    SciTech Connect

    Swallow, K.C.; Killilea, W.R.; Hong, G.T.; Bourhis, A.L.

    1993-08-03

    A method is described for substantially completely oxidizing combustible materials in which an aqueous stream bearing the combustible materials is reacted in the presence of an oxidant comprising diatomic oxygen and at a temperature greater than the critical temperature of water and at a pressure greater than about 25 bar, within a reactor for a period of less than about 5 minutes to produce a reaction product stream, wherein the reaction is initiated in the presence of a rate enhancer comprising at least one oxidizing agent in addition to said oxidant selected from the group consisting of ozone, hydrogen peroxide, salts containing persulfate, salts containing permanganate, nitric acid, salts containing nitrate, oxyacids of chlorine and their corresponding salts, hypochlorous acid, salts containing hypochlorite, chlorous acid, salts containing chlorite, chloric acid, salts containing chlorate, perchloric acid, and salts containing perchlorate.

  14. Oxygen transfer rates in shaken culture vessels from Fernbach flasks to microtiter plates.

    PubMed

    Running, Jeffrey A; Bansal, Karan

    2016-08-01

    By a sulfite oxidation method, oxygen transfer rates (OTRs) were determined in 11 types of culture vessels from 2.8-L Fernbach (FB) flasks to 96-, 48-, and 24-well square deepwell microtiter plates (MTPs). OTRs ranged from 140 mM/h in 250-mL Ultrayield™ flasks shaken at 300 rpm with a 50 mm diameter shaker throw to 5 mM/h in unbaffled FBs shaken at 200 rpm with a 25 mm throw. Baffles in FBs increased OTRs 6-12-fold under various shaking conditions, and up to five-fold in 250-mL flasks, depending on the type of baffles. Corner-baffling was superior to bottom-baffling in glass, 250-mL flasks. In MTPs, OTRs increased with increasing well size and decreasing fill volume. At 50 mm throw and 300 rpm, 24-well MTPs had OTRs comparable to corner-baffled, 250-mL flasks (∼100 mM/h). The OTRs in unbaffled flasks were relatively insensitive to shaking conditions, increasing less than two-fold between the most modest and the most vigorous conditions. There was no consistency across vessels as to whether the alternate incubation conditions of 70 mm throw and 250 rpm produced higher OTRs than the 50 mm throw and 300 rpm regimen. No increase in OTR was seen in any MTP when the cover hole diameter was increased beyond 4.5 mm. OTRs decreased as viscosity increased, falling smoothly in unbaffled flasks and 24-well MTPs, but 48-well and 96-well MTPs showed precipitous OTR drops as viscosity increased. Matching the OTRs of screening vessels to the oxygen uptake rates of microbial cultures can greatly reduce the number of false positive strains that are forwarded from microbial screens. Biotechnol. Bioeng. 2016;113: 1729-1735. © 2016 Wiley Periodicals, Inc. PMID:26806816

  15. Improved vitamin B(12) production by step-wise reduction of oxygen uptake rate under dissolved oxygen limiting level during fermentation process.

    PubMed

    Wang, Ze-Jian; Wang, Hui-Yuan; Li, Yong-Liang; Chu, Ju; Huang, Ming-Zhi; Zhuang, Ying-Ping; Zhang, Si-Liang

    2010-04-01

    Effects of different oxygen transfer rates (OTR) on the cell growth and vitamin B(12) biosynthesis of Pseudomonas denitrificans were first investigated under dissolved oxygen limiting conditions. The results demonstrated that high OTR accelerated cell growth and initial vitamin B(12) biosynthesis rate, while lower OTR was critical for higher productivity in the late fermentation process. The oxygen uptake rates (OUR) corresponded well with OTR. Based on the metabolic intermediate analysis, a step-wise OUR control strategy was proposed. The strategy was successfully implemented in scale-up to an industrial fermenter (120,000 l). A stable maximum vitamin B(12) production of 208 + or - 2.5 mg/l was achieved, which was increased by 17.3% compared with the control. Furthermore, the glucose consumption coefficient to vitamin B(12) was 34.4% lower than that of the control. An efficient and economical fermentation process based on OUR criterion was established for industrial vitamin B(12) fermentation by P. denitrificans. PMID:20022743

  16. Kinetics of thermal decomposition of styrene-butadiene rubber at low heating rates in nitrogen and oxygen

    SciTech Connect

    Chen, K.S.; Yeh, R.Z.; Chang, Y.R.

    1997-03-01

    The kinetics of thermal decomposition of styrene-butadiene rubber have been investigated thermogravimetrically under various heating rates either in nitrogen or mixed with 5--25% oxygen in nitrogen. The results show that in pure nitrogen the reaction involves only one stage, with an initial reaction temperature of 622--661 K and an apparent activation energy at 211 {+-} 15 kJ/mol. The initial reaction temperature decreases, but the reaction rate and its temperature range increase when the heating rate is increased. When oxygen is present, the reaction involves two parallel steps. The fractional conversion at the end of the first reaction is 0.83--0.87, depending on the oxygen concentration. Although the presence of oxygen somewhat delays the start of the initial reaction, the activation energy is reduced significantly, so that its rate becomes faster once reaction commences. The complete rate equation for both stages of reaction was obtained by summing the individual weighted rate equations; the weighting factors were determined from the fractional conversion at the end of the first reaction.

  17. Watershed Influences on Residence Time and Oxygen Reduction Rates in an Agricultural Landscape

    NASA Astrophysics Data System (ADS)

    Shope, C. L.; Tesoriero, A. J.

    2015-12-01

    Agricultural use of synthetic fertilizers and animal manure has led to increased crop production, but also elevated nitrogen concentrations in groundwater, resulting in impaired water quality. Groundwater oxygen concentrations are a key indicator of potential biogeochemical processes, which control water/aquifer interactions and contaminant transport. The U.S. Geological Survey's National Water-Quality Assessment Program has a long-history of studying nutrient transport and processing across the United States and the Glacial Aquifer system in particular. A series of groundwater well networks in Eastern Wisconsin is being used to evaluate the distribution of redox reaction rates over a range of scales with a focus on dissolved O2 reduction rates. An analysis of these multi-scale networks elucidates the influence of explanatory variables (i.e.: soil type, land use classification) on reduction rates and redox reactions throughout the Fox-Wolf-Peshtigo watersheds. Multiple tracers including dissolved gasses, tritium, helium, chlorofluorocarbons, sulfur hexafluoride, and carbon-14 were used to estimate groundwater ages (0.8 to 61.2 yr) at over 300 locations. Our results indicate O2 reduction rates along a flowpath study area (1.2 km2) of 0.15 mg O2 L-1 yr-1 (0.12 to 0.18 mg O2 L-1 yr-1) up to 0.41 mg O2 L-1 yr-1 (0.23 to 0.89 mg O2 L-1 yr-1) for a larger scale land use study area (3,300 km2). Preliminary explanatory variables that can be used to describe the variability in reduction rates include soil type (hydrologic group, bulk density) and chemical concentrations (nitrite plus nitrate, silica). The median residence time expected to reach suboxic conditions (≤ 0.4 mg O2 L-1) for the flowpath and the land use study areas was 66 and 25 yr, respectively. These results can be used to elucidate and differentiate the impact of residence time on groundwater quality vulnerability and sustainability in agricultural regions without complex flow models.

  18. Cerebral metabolic rate of oxygen (CMRO2) assessed by combined Doppler and spectroscopic OCT

    PubMed Central

    Chong, Shau Poh; Merkle, Conrad W.; Leahy, Conor; Srinivasan, Vivek J.

    2015-01-01

    A method of measuring cortical oxygen metabolism in the mouse brain that uses independent quantitative measurements of three key parameters: cerebral blood flow (CBF), arteriovenous oxygen extraction (OE), and hemoglobin concentration ([HbT]) is presented. Measurements were performed using a single visible light spectral/Fourier domain OCT microscope, with Doppler and spectroscopic capabilities, through a thinned-skull cranial window in the mouse brain. Baseline metabolic measurements in mice are shown to be consistent with literature values. Oxygen consumption, as measured by this method, did not change substantially during minor changes either in the fraction of inspired oxygen (FiO2) or in the fraction of inspired carbon dioxide (FiCO2), in spite of larger variations in oxygen saturations. This set of experiments supports, but does not prove, the validity of the proposed method of measuring brain oxygen metabolism. PMID:26504644

  19. Microbial degradation rates of small peptides and amino acids in the oxygen minimum zone of Chilean coastal waters

    NASA Astrophysics Data System (ADS)

    Pantoja, Silvio; Rossel, Pamela; Castro, Rodrigo; Cuevas, L. Antonio; Daneri, Giovanni; Córdova, Candy

    2009-07-01

    We found similar microbial degradation rates of labile dissolved organic matter in oxic and suboxic waters off northern Chile. Rates of peptide hydrolysis and amino acid uptake in unconcentrated water samples were not low in the water column where oxygen concentration was depleted. Hydrolysis rates ranged from 65 to 160 nmol peptide L -1 h -1 in the top 20 m, 8-28 nmol peptide L -1 h -1 between 100 and 300 m (O 2-depleted zone), and 14-19 nmol peptide L -1 h -1 between 600 and 800 m. Dissolved free amino acid uptake rates were 9-26, 3-17, and 6 nmol L -1 h -1 at similar depth intervals. Since these findings are consistent with a model of comparable potential activity of microbes in degrading labile substrates of planktonic origin, we suggest, as do other authors, that differences in decomposition rates with high and low oxygen concentrations may be a matter of substrate lability. The comparison between hydrolysis and uptake rates indicates that microbial peptide hydrolysis occurs at similar or faster rates than amino acid uptake in the water column, and that the hydrolysis of peptides is not a rate-limiting step for the complete remineralization of labile macromolecules. Low O 2 waters process about 10 tons of peptide carbon per h, double the amount processed in surface-oxygenated water. In the oxygen minimum zone, we suggest that the C balance may be affected by the low lability of the dissolved organic matter when this is upwelled to the surface. An important fraction of dissolved organic matter is processed in the oxygen minimum layer, a prominent feature of the coastal ocean in the highly productive Humboldt Current System.

  20. TMI Rain Rate Estimation Over Land and Ocean Utilizing Convective and Stratiform Discrimination

    NASA Technical Reports Server (NTRS)

    Prabhakara, C.; Iacovazzi, R., Jr.; Weinman, J. A.; Dalu, G.

    1999-01-01

    Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) radiometer brightness temperature data in the 85 GHz channel (T85) reveal distinct local minima in a regional map containing a Mesoscale Convective System (MCS). This is because of relatively small footprint size (approximately 5.5 km) and strong extinction properties in this channel of the TMI. A map of rain rate for that region, deduced from simultaneous measurements made by the Precipitation Radar (PR) on board the TRMM satellite, reveals that these T85 minima, produced by scattering, correspond to local PR rain maxima. Utilizing the PR rain rate map as a guide, we infer from TMI data the presence of three different kinds of thunderstorms or Cbs. They are young, mature, and decaying Cbs that have a scale of about 20 km on the average. Two parameters enable us to infer these three kinds of Cbs objectively: a) the magnitude of scattering depression deduced from local T85 minima and b) the mean horizontal gradient of T85 around such minima. Knowing the category of a given Cb, we can estimate the rain rate associated with it. Such estimation is done with the help of relationships linking T85 minimum to rain rate in each Cb type. Similarly, a weak background rain rate in all the areas where T85 is less than 260 K is deduced with another relationship linking T85 to rain rate. In our rain retrieval model, this background rain constitutes the stratiform rain where the Cbs are absent. Initially, these relationships are optimized or tuned utilizing the PR and TMI data of a few MCS events. After such tuning, the model is applied to independent MCS cases. The areal distribution of light (1-10 mm/hr), moderate (10-20 mm/hr), and intense (> 20 mm/hr) rain rates are retrieved satisfactorally. Accuracy in the estimates of the light, moderate and intense rain areas and the mean rain rates associated with such areas in these independent MCS cases is on the average about 15%. Taking advantage of this ability of our

  1. The optimization of incident angles of low-energy oxygen ion beams for increasing sputtering rate on silicon samples

    NASA Astrophysics Data System (ADS)

    Sasaki, T.; Yoshida, N.; Takahashi, M.; Tomita, M.

    2008-12-01

    In order to determine an appropriate incident angle of low-energy (350-eV) oxygen ion beam for achieving the highest sputtering rate without degradation of depth resolution in SIMS analysis, a delta-doped sample was analyzed with incident angles from 0° to 60° without oxygen bleeding. As a result, 45° incidence was found to be the best analytical condition, and it was confirmed that surface roughness did not occur on the sputtered surface at 100-nm depth by using AFM. By applying the optimized incident angle, sputtering rate becomes more than twice as high as that of the normal incident condition.

  2. Upper limit on the rate constant for isotope exchange between molecular oxygen and ozone at 298 K

    NASA Technical Reports Server (NTRS)

    Anderson, S. M.; Morton, J.; Mauersberger, K.

    1987-01-01

    The gas phase bimolecular isotope exchange reaction between molecular oxygen and ozone has been investigated directly for the first time. Its rate coefficient is found to be less than 2 x 10 to the -25th cu cm/sec at 298 K, over six orders of magnitude below recent estimates. Much faster exchange was observed over condensed ozone at 77 K, suggesting isotopic scrambling is catalyzed under these conditions. The low rate coefficient implies that homogeneous exchange between ground state oxygen and ozone molecules cannot play a significant role in heavy ozone chemistry.

  3. MRI-based methods for quantification of the cerebral metabolic rate of oxygen.

    PubMed

    Rodgers, Zachary B; Detre, John A; Wehrli, Felix W

    2016-07-01

    The brain depends almost entirely on oxidative metabolism to meet its significant energy requirements. As such, the cerebral metabolic rate of oxygen (CMRO2) represents a key measure of brain function. Quantification of CMRO2 has helped elucidate brain functional physiology and holds potential as a clinical tool for evaluating neurological disorders including stroke, brain tumors, Alzheimer's disease, and obstructive sleep apnea. In recent years, a variety of magnetic resonance imaging (MRI)-based CMRO2 quantification methods have emerged. Unlike positron emission tomography - the current "gold standard" for measurement and mapping of CMRO2 - MRI is non-invasive, relatively inexpensive, and ubiquitously available in modern medical centers. All MRI-based CMRO2 methods are based on modeling the effect of paramagnetic deoxyhemoglobin on the magnetic resonance signal. The various methods can be classified in terms of the MRI contrast mechanism used to quantify CMRO2: T2*, T2', T2, or magnetic susceptibility. This review article provides an overview of MRI-based CMRO2 quantification techniques. After a brief historical discussion motivating the need for improved CMRO2 methodology, current state-of-the-art MRI-based methods are critically appraised in terms of their respective tradeoffs between spatial resolution, temporal resolution, and robustness, all of critical importance given the spatially heterogeneous and temporally dynamic nature of brain energy requirements. PMID:27089912

  4. Heart rate variability and arterial oxygen saturation response during extreme normobaric hypoxia.

    PubMed

    Botek, Michal; Krejčí, Jakub; De Smet, Stefan; Gába, Aleš; McKune, Andrew J

    2015-07-01

    The primary purpose of this study was to assess the response of autonomic cardiac activity and changes in the arterial oxygen saturation (SpO2) during normobaric hypoxia and subsequent recovery. Heart rate variability (HRV) and SpO2 were monitored in a supine position during hypoxia (FiO2=9.6%) for 10min, and normoxic recovery in 29 subjects. Spectral analysis of HRV quantified the autonomic cardiac activity by means of low frequency (LF) (0.05-0.15Hz) and high frequency (HF) (0.15-0.50Hz) power transformed by natural logarithm (Ln). Based on the SpO2 response to hypoxia, the subjects were divided into Resistant (RG, SpO2=80.8±7.0%) or Sensitive (SG, SpO2=67.2±2.9%) group. The SpO2 and vagal activity (LnHF) significantly decreased during hypoxia in both groups. A withdrawal in vagal activity was significantly greater in SG compared to RG. Moreover, only in SG, a relative increase in sympathetic modulation (Ln LF/HF) during hypoxia occurred. Correlations (r=-0.461, and r=0.595, both P<0.05) between ΔSpO2 (delta) and ΔLn LF/HF, and ΔLnHF were found. Based on results, it seems that SpO2 level could be an important factor that influences the autonomic cardiac response in hypoxia. PMID:25907329

  5. Spontaneous variability in minute ventilation oxygen consumption and heart rate of low birth weight infants.

    PubMed

    Schulze, K; Kairam, R; Stefanski, M; Sciacca, R; Bateman, D; Dell, R; James, L S

    1981-08-01

    Continuous measurements of minute ventilation (VI), oxygen consumption (VO2), heart rate (HR), activity, and temperature were made in eleven low birth weight infants during the interval between feedings. Significant increases in VI, VO2, and HR were noted between quiet and active sleep. (VI Active - VI Quiet/VI Quiet) X 100 = 18.4% VO2 Active - VO2 Quiet/VO2 Quiet) X 100 = 10.1% and HR Active - HR Quiet/HR Quiet) X 100 = 6.4%. Significant differences were also noted within epochs of the same state of sleep: mean slope VI versus time in epoch (t) = -156 ml/kg . min/hr, VO2 versus t. = 1.49 ml/kg . min/hr and HR versus t = -15.0 beats/min/hr. Differences between successive epochs of the same state of sleep were also observed: VI, +5.9 to 46.6%; VO2, 4.7 to 24.6%; HR, 1.0 to 9.7%. These differences were related to the length of time after feeding. These data indicate that steady state conditions do not occur in growing low birth weight infants and that the design of studies of respiration and metabolism in these infants should include continuous assessment of the state of sleep or activity and time after feeding to ensure that experimental and control periods are truly comparable. PMID:7267185

  6. 40 CFR Table I-5 to Subpart I of... - Default Emission Factors (1-Uij) for Gas Utilization Rates (Uij) and By-Product Formation Rates...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Default Emission Factors (1-Uij) for Gas Utilization Rates (Uij) and By-Product Formation Rates (Bijk) for MEMS Manufacturing I Table I-5...) and By-Product Formation Rates (Bijk) for MEMS Manufacturing ER13NO13.021...

  7. 40 CFR Table I-5 to Subpart I of... - Default Emission Factors (1-Uij) for Gas Utilization Rates (Uij) and By-Product Formation Rates...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Default Emission Factors (1-Uij) for Gas Utilization Rates (Uij) and By-Product Formation Rates (Bijk) for MEMS Manufacturing I Table I-5...) and By-Product Formation Rates (Bijk) for MEMS Manufacturing Process type factors Process gas i...

  8. Accuracy of different oxygenation indices in estimating intrapulmonary shunting at increasing infusion rates of dobutamine in horses under general anaesthesia.

    PubMed

    Briganti, A; Portela, D A; Grasso, S; Sgorbini, M; Tayari, H; Bassini, J R Fusar; Vitale, V; Romano, M S; Crovace, A; Breghi, G; Staffieri, F

    2015-06-01

    The aim of this study was to evaluate the correlation of commonly used oxygenation indices with venous admixture (Qs/Qt) in anaesthetised horses under different infusion rates of dobutamine. Six female horses were anaesthetised with acepromazine, xylazine, diazepam, ketamine, and isoflurane, and then intubated and mechanically ventilated with 100% O2. A Swan-Ganz catheter was introduced into the left jugular vein and its tip advanced into the pulmonary artery. Horses received different standardised rates of dobutamine. For each horse, eight samples of arterial and mixed venous blood were simultaneously obtained at fixed times. Arterial and venous haemoglobin (Hb) concentration and O2 saturation, arterial oxygen partial pressure (PaO2), venous oxygen partial pressure (PvO2), and barometric pressure were measured. Arterial (CaO2), mixed venous (CvO2), and capillary (Cc'O2) oxygen contents were calculated using standard formulae. The correlations between F-shunt, arterial oxygen tension to fraction of inspired oxygen ratio (PaO2/FiO2), arterial to alveolar oxygen tension ratio (PaO2/PAO2), alveolar to arterial oxygen tension difference (P[A - a]O2), and respiratory index (P[A - a]O2/PaO2) were tested with linear regression analysis. The goodness-of-fit for each calculated formula was evaluated by means of the coefficient of determination (r(2)). The agreement between Qs/Qt and F-shunt was analysed with the Bland-Altman test. All tested oxygen tension-based indices were weakly correlated (r(2) < 0.2) with the Qs/Qt, whereas F-shunt showed a stronger correlation (r(2) = 0.73). F-shunt also showed substantial agreement with Qs/Qt independent of the dobutamine infusion rate. F-shunt better correlated with Qs/Qt than other oxygen indices in isoflurane-anaesthetised horses under different infusion rates of dobutamine. PMID:25920771

  9. Oxygen consumption and heart rate responses to isolated ballet exercise sets.

    PubMed

    Rodrigues-Krause, Josianne; Dos Santos Cunha, Giovani; Alberton, Cristine Lima; Follmer, Bruno; Krause, Mauricio; Reischak-Oliveira, Alvaro

    2014-01-01

    Ballet stage performances are associated with higher cardiorespiratory demand than rehearsals and classes. Hence, new interest is emerging to create periodized training that enhances dancers' fitness while minimizing delayed exercise-induced fatigue and possible injuries. Finding out in what zones of intensity dancers work during different ballet movements may support the use of supplemental training adjusted to the needs of the individual dancer. Therefore, the main purpose of this study was to describe dancers' oxygen consumption (VO2) and heart rate (HR) responses during the performance of nine isolated ballet exercise sets, as correlated with their first and second ventilatory thresholds (VT1 and VT2). Twelve female ballet dancers volunteered for the study. Their maximum oxygen consumption (VO2max), VT1, and VT2 were determined by use of an incremental treadmill test. Nine sets of ballet movements were assessed: pliés, tendus, jetés, rond de jambes, fondus, grand adage (adage), grand battements, temps levés, and sautés. The sets were randomly executed and separated by 5 minute rest periods. ANOVA for repeated measurements followed by the Bonferroni Post-hoc test were applied (p < 0.05). VO2 responses were as follows: pliés (17.6 ± 1.6 ml·kg(-1)·min(-1)); tendus and adage were not significantly greater than VT1; rond de jambes (21.8 ± 3.1 ml·kg(-1) ·min(-1)); fondus and jetés were higher than VT1 and the previous exercises; grand battements (25.8 ± 2.9 ml·kg(-1)·min(-1)) was greater than all the other exercises and VT1; and VT2 was significantly higher than all ballet sets. This stratification followed closely, but not exactly, the variation in HR. For example, rond de jambes (156.8 ± 19 b·min(-1)) did not show any significant difference from all the other ballet sets, nor VT1 or VT2. It is concluded that the workloads of isolated ballet sets, based on VO2 responses, vary between low and moderate aerobic intensity in relation to dancers' VT1 and

  10. Bulk Dissolution Rates of Cadmium and Bismuth Tellurides As a Function of pH, Temperature and Dissolved Oxygen.

    PubMed

    Biver, Marc; Filella, Montserrat

    2016-05-01

    The toxicity of Cd being well established and that of Te suspected, the bulk, surface-normalized steady-state dissolution rates of two industrially important binary tellurides-polycrystalline cadmium and bismuth tellurides- were studied over the pH range 3-11, at various temperatures (25-70 °C) and dissolved oxygen concentrations (0-100% O2 in the gas phase). The behavior of both tellurides is strikingly different. The dissolution rates of CdTe monotonically decreased with increasing pH, the trend becoming more pronounced with increasing temperature. Activation energies were of the order of magnitude associated with surface controlled processes; they decreased with decreasing acidity. At pH 7, the CdTe dissolution rate increased linearly with dissolved oxygen. In anoxic solution, CdTe dissolved at a finite rate. In contrast, the dissolution rate of Bi2Te3 passed through a minimum at pH 5.3. The activation energy had a maximum in the rate minimum at pH 5.3 and fell below the threshold for diffusion control at pH 11. No oxygen dependence was detected. Bi2Te3 dissolves much more slowly than CdTe; from one to more than 3.5 orders of magnitude in the Bi2Te3 rate minimum. Both will readily dissolve under long-term landfill deposition conditions but comparatively slowly. PMID:27043466

  11. A refined method for quantification of myocardial oxygen consumption rate using mean transit time with carbon-11-acetate and dynamic PET.

    PubMed

    Choi, Y; Huang, S C; Hawkins, R A; Hoh, C K; Krivokapich, J; Buxton, D B; Armbrecht, J J; Sun, K T; Phelps, M E; Schelbert, H R

    1993-11-01

    The utility of the mean transit time equation was investigated for estimation of the myocardial clearance rate constant of 11C-acetate, which is proportional to myocardial oxygen consumption rates. The mean transit time approach was also employed to generate parametric images of the clearance rate constant of 11C-acetate with dynamic PET imaging in 20 normal human studies. Input function delays and cutoff errors due to the truncation of the myocardial tissue time-activity curve at a finite time were corrected. The clearance rate constants estimated by mean transit time correlated well with the estimates by conventional monoexponential fitting (15 min (truncation time): Y = 0.01 + 0.94X, correlated coefficient (r) = 0.99; 16 min: Y = 0.03 + 0.94X, r = 0.98; 20 min: Y = 0.03 + 0.84X, r = 0.99). The clearance rate constants estimated by the mean transit time approach also correlated well (r = 0.94) with the measured rate-pressure products. The quality and noise level of parametric images of the clearance rate constants generated by mean transit time are improved over those generated by monoexponential fitting. Additional advantages of the mean transit time approach compared to the standard monoexponential fitting method for estimating myocardial clearance rate constant of 11C-acetate include ease of input function delay correction, less sensitivity to the shape of the input function and elimination of subjective data selection of the linear portion of the clearance data on a semilog plot. Thus, this approach is expected to facilitate objective quantitative analysis of indices of myocardial oxygen consumption. PMID:8229256

  12. Higher Rates of Retinopathy of Prematurity after Increasing Oxygen Saturation Targets for Very Preterm Infants: Experience in a Single Center.

    PubMed

    Manley, Brett J; Kuschel, Carl A; Elder, James E; Doyle, Lex W; Davis, Peter G

    2016-01-01

    Randomized trials of oxygen saturation target ranges for extremely preterm infants showed increased survival but increased retinopathy of prematurity with higher compared with lower target ranges. In our center, changing from a target range of 88%-92% to 91%-95% has been associated with increased rates and severity of retinopathy of prematurity. PMID:26548746

  13. Effects of pressure, oxygen concentration, and forced convection on flame spread rate of Plexiglas, Nylon and Teflon

    NASA Technical Reports Server (NTRS)

    Notardonato, J. J.; Burkhardt, L. A.; Cochran, T. H.

    1974-01-01

    Experiments were conducted in which the burning of cylindrical materials in a flowing oxidant stream was studied. Plexiglas, Nylon, and Teflon fuel specimens were oriented such that the flames spread along the surface in a direction opposed to flowing gas. Correlations of flame spread rate were obtained that were power law relations in terms of pressure, oxygen concentration, and gas velocity.

  14. Automatic adjustment clauses in public-utility rate schedules. A staff report on the implementation of Section 208 of the Public Utility Regulatory Policies Act of 1978

    SciTech Connect

    Not Available

    1982-02-01

    The Public Utility Regulatory Policies Act (PURPA), enacted November 8, 1978, directs the Federal Energy Regulatory Commission to make a comprehensive review of certain matters related to automatic adjustment clauses in electric rate schedules used by public utilities subject to the Commission's jurisdiction. The first requirement is that the Commission review automatic adjustment clauses in utility rate schedules to examine whether the clauses effectively provide incentives for efficient use of resources and also whether the clauses reflect only those costs that are either subject to periodic fluctuations or not susceptible to precise determinations in rate cases prior to the time the costs are incurred. The second requirement is that the Commission review the practices of each public utility under automatic adjustment clauses to insure efficient use of resources under such clauses. In response to these requirements, the Commission instituted a study and a staff investigation to examine the matters specifically identified in the Act. This report describes the progress that has been made in the study during the first two years since the passage of the Act related to the issues involved. The principal types of automatic adjustment clauses appearing in rate schedules subject to FERC jurisdiction are described and the extent of use of the types of clauses is indicated. The nature and results of the efforts made to analyze incentive effects, variability and predictability of certain costs, and the fuel procurement practices of utilities as related to automatic adjustment clauses are discussed. Preliminary staff conclusions from the review and analysis effort are presented.

  15. Density Predictions of Mercury's Exosphere Utilizing HEMO, the Hermean Exosphere Model of Oxygen, Including the Effects of Photodissociation

    NASA Astrophysics Data System (ADS)

    Grotheer, E.; Mangano, V.; Livi, S. A.

    2014-12-01

    The work presented here builds on the results of Grotheer & Livi [2014], which found that the majority of the vapor produced due to meteoroid impacts on Mercury is caused by meteoroids with masses 4.2 x 10-7 g ≤ m ≤ 8.3 x 10-2 g. Meteoroids with a mass of 2.1 x 10-4 g are the largest contributors to the vapor released by meteoroid impacts, thus here we focus on meteoroids with such masses as an input to a particle tracing simulation called the Hermean Exosphere Model of Oxygen (HEMO). The HEMO simulations include 36 different particle species which can be released via meteoritic impact vaporization, based on the abundances determined by Berezhnoy & Klumov [2008]. After the initial simulation of the meteoroid impact, the released particles are affected by the gravitational pull of the planet Mercury, as well as the Sun's radiation. Particles may be photoionized or in the case of molecules also photodissociated. Due to the effects of photodissociation, a total of 38 species are actually present in the simulation, since 2 species are not directly released by impact vaporization but may be created due to photodissociation. These simulations record various pieces of information about each simulated particle, including position and velocity, for each time-step of the model. This information is then utilized to construct density profiles for each simulation run, as well as for aggregates of simulation runs with similar input parameters. The results are intended to aid the interpretation of results from the MESSENGER and BepiColombo missions to Mercury, with a particular focus on atomic and molecular oxygen. ReferencesAlexey A. Berezhnoy and Boris A. Klumov. Impacts as sources of the exosphere on Mercury. Icarus, 195(2): 511-522, 2008. Emmanuel B. Grotheer and Stefano A. Livi. Small meteoroids' major contribution to Mercury's exosphere. Icarus, 227(1): 1-7, 2014.

  16. Optically based quantification of absolute cerebral metabolic rate of oxygen (CMRO2) with high spatial resolution in rodents

    NASA Astrophysics Data System (ADS)

    Yaseen, Mohammad A.; Srinivasan, Vivek J.; Sakadžić, Sava; Vinogradov, Sergei A.; Boas, David A.

    2010-02-01

    Measuring oxygen delivery in brain tissue is important for identifying the pathophysiological changes associated with brain injury and various diseases such as cancer, stroke, and Alzheimer's disease. We have developed a multi-modal imaging system for minimally invasive measurement of cerebral oxygenation and blood flow in small animals with high spatial resolution. The system allows for simultaneous measurement of blood flow using Fourier-domain optical coherence tomography, and oxygen partial pressure (pO2) using either confocal or multiphoton phosphorescence lifetime imaging with exogenous porphyrin-based dyes sensitive to dissolved oxygen. Here we present the changes in pO2 and blood flow in superficial cortical vessels of Sprague Dawley rats in response to conditions such as hypoxia, hyperoxia, and functional stimulation. pO2 measurements display considerable heterogeneity over distances that cannot be resolved with more widely used oxygen-monitoring techniques such as BOLD-fMRI. Large increases in blood flow are observed in response to functional stimulation and hypoxia. Our system allows for quantification of cerebral metabolic rate of oxygen (CMRO2) with high spatial resolution, providing a better understanding of metabolic dynamics during functional stimulation and under various neuropathologies. Ultimately, better insight into the underlying mechanisms of neuropathologies will facilitate the development of improved therapeutic strategies to minimize damage to brain tissue.

  17. A CENSUS OF OXYGEN IN STAR-FORMING GALAXIES: AN EMPIRICAL MODEL LINKING METALLICITIES, STAR FORMATION RATES, AND OUTFLOWS

    SciTech Connect

    Zahid, H. J.; Dima, G. I.; Kewley, L. J.; Erb, D. K.; Dave, R.

    2012-09-20

    In this contribution, we present the first census of oxygen in star-forming galaxies in the local universe. We examine three samples of galaxies with metallicities and star formation rates (SFRs) at z = 0.07, 0.8, and 2.26, including the Sloan Digital Sky Survey (SDSS) and DEEP2 survey. We infer the total mass of oxygen produced and mass of oxygen found in the gas-phase from our local SDSS sample. The star formation history is determined by requiring that galaxies evolve along the relation between stellar mass and SFR observed in our three samples. We show that the observed relation between stellar mass and SFR for our three samples is consistent with other samples in the literature. The mass-metallicity relation is well established for our three samples, and from this we empirically determine the chemical evolution of star-forming galaxies. Thus, we are able to simultaneously constrain the SFRs and metallicities of galaxies over cosmic time, allowing us to estimate the mass of oxygen locked up in stars. Combining this work with independent measurements reported in the literature, we conclude that the loss of oxygen from the interstellar medium of local star-forming galaxies is likely to be a ubiquitous process with the oxygen mass loss scaling (almost) linearly with stellar mass. We estimate the total baryonic mass loss and argue that only a small fraction of the baryons inferred from cosmological observations accrete onto galaxies.

  18. Can the cerebral metabolic rate of oxygen be estimated with near-infrared spectroscopy?

    NASA Astrophysics Data System (ADS)

    Boas, D. A.; Strangman, G.; Culver, J. P.; Hoge, R. D.; Jasdzewski, G.; Poldrack, R. A.; Rosen, B. R.; Mandeville, J. B.

    2003-08-01

    We have measured the changes in oxy-haemoglobin and deoxy-haemoglobin in the adult human brain during a brief finger tapping exercise using near-infrared spectroscopy (NIRS). The cerebral metabolic rate of oxygen (CMRO2) can be estimated from these NIRS data provided certain model assumptions. The change in CMRO2 is related to changes in the total haemoglobin concentration, deoxy-haemoglobin concentration and blood flow. As NIRS does not provide a measure of dynamic changes in blood flow during brain activation, we relied on a Windkessel model that relates dynamic blood volume and flow changes, which has been used previously for estimating CMRO2 from functional magnetic resonance imaging (fMRI) data. Because of the partial volume effect we are unable to quantify the absolute changes in the local brain haemoglobin concentrations with NIRS and thus are unable to obtain an estimate of the absolute CMRO2 change. An absolute estimate is also confounded by uncertainty in the flow-volume relationship. However, the ratio of the flow change to the CMRO2 change is relatively insensitive to these uncertainties. For the finger tapping task, we estimate a most probable flow-consumption ratio ranging from 1.5 to 3 in agreement with previous findings presented in the literature, although we cannot exclude the possibility that there is no CMRO2 change. The large range in the ratio arises from the large number of model parameters that must be estimated from the data. A more precise estimate of the flow-consumption ratio will require better estimates of the model parameters or flow information, as can be provided by combining NIRS with fMRI.

  19. Research on the Algorithm for 3L-CVRP with Considering the Utilization Rate of Vehicles

    NASA Astrophysics Data System (ADS)

    Ma, Han-Wu; Zhu, Wei; Xu, Sen

    Integrated optimization of vehicle routing problem and container loading problem has become a research hotspot in current logistics distribution. Firstly, a mathematical model of the three-dimensional loading capacitated vehicle routing problem (3L-CVRP) is made out under the assumption of which the delivered items are rectangular, considering the rotation of items, last in first out (LIFO) rule and the loading of fragile items which are all in accordance with the realistic conditions, and the objective is to minimize the total driving distance and maximize the utilization rate of vehicle. Then, in order to solve this problem, this paper divides the process of routing and loading into two levels, and a new algorithm which combined Tabu Search (TS) with Local Search (LS) is presented. At last, the feasibility and effectiveness of the method and algorithm is proved by the adoption example.

  20. Electric Utility Rate Design Study: comments on An Evaluation of Four Marginal-Costing Methodologies

    SciTech Connect

    Not Available

    1980-06-12

    This report is an extension of NP-24255 (EAPA 6:1820), An Evaluation of Four Marginal Costing Methodologies (RDS No. 66), which summarizes, contrasts, and evaluates four marginal costing methodologies currently in use by various electric utilities. The proponents of the four methodologies evaluated by Temple, Barker, and Sloane (TBS) were asked to comment on the TBS report (RDS No. 66). Other selected reviewers were asked to comment on the TBS report. This report, RDS No. 67, is an anthology of all those comments plus a response to them by TBS. The rebuttal comments from TBS appear first, followed by comments submitted by Ralph Turvey, an authority in microeconomics. The next comments are to the Rate Design Study by members of Advisory Group I, experts in the field of electricity pricing. The next four sections present detailed comments submitted by the four marginal-cost proponents: Cicchetti, Gillen, and Smolensky; Ernst and Ernst; Gordian Associates; and National Economic Research Associates.

  1. Electrocatalyst for oxygen reduction with reduced platinum oxidation and dissolution rates

    SciTech Connect

    Adzic, Radoslav; Zhang, Junliang; Vukmirovic, Miomir

    2012-11-13

    The invention relates to platinum-metal oxide composite particles and their use as electrocatalysts in oxygen-reducing cathodes and fuel cells. The invention particularly relates to methods for preventing the oxidation of the platinum electrocatalyst in the cathodes of fuel cells by use of these platinum-metal oxide composite particles. The invention additionally relates to methods for producing electrical energy by supplying such a fuel cell with an oxidant, such as oxygen, and a fuel source, such as hydrogen.

  2. Electrocatalyst for oxygen reduction with reduced platinum oxidation and dissolution rates

    DOEpatents

    Adzic, Radoslav; Zhang, Junliang; Vukmirovic, Miomir

    2011-11-22

    The invention relates to platinum-metal oxide composite particles and their use as electrocatalysts in oxygen-reducing cathodes and fuel cells. The invention particularly relates to methods for preventing the oxidation of the platinum electrocatalyst in the cathodes of fuel cells by use of these platinum-metal oxide composite particles. The invention additionally relates to methods for producing electrical energy by supplying such a fuel cell with an oxidant, such as oxygen, and a fuel source, such as hydrogen.

  3. Utilization of electromigration in civil and environmental engineering--processes, transport rates and matrix changes.

    PubMed

    Ottosen, Lisbeth M; Christensen, Iben V; Rorig-Dalgård, Inge; Jensen, Pernille E; Hansen, Henrik K

    2008-07-01

    Electromigration (movement of ions in an applied electric field) is utilized for supply or extraction of ions from various porous materials within both civil and environmental engineering. In civil engineering, most research has been conducted on the removal of chlorides from concrete to hinder reinforcement corrosion while in environmental engineering remediation of heavy metal polluted soil is the issue most studied. Never the less, experiments have been conducted with utilization for several other materials and purposes within both engineering fields. Even though there are many topics of common interest in the use of electromigration for the two fields, there is no tradition for collaboration. The present paper is a review with the aim of pointing out areas of shared interest. Focus is laid on the purposes of the different processes, transport rates of various ions in different materials and on changes in the matrix itself. Desorption and dissolution of the target elements into ionic form is a key issue to most of the processes, and can be the limiting step. The removal rate is generally below 1 cm day(- 1), but it can be much less than 1 mm day(- 1) when desorption is slow and insufficient. Matrix changes occurs under the action of the applied electric field and it includes both physico-chemical and hydrological changes. Some of the solid phases is weathered and new can be formed. Increased fundamental understanding of the effects and side effects, when applying the electric field to a porous material, can lead to improvement of the known technologies and possibly to new applications. PMID:18569289

  4. Longitudinal Analyses of Geographic Differences in Utilization Rates of Children with Developmental Delays Who Participation in Early Intervention Services

    ERIC Educational Resources Information Center

    Lin, Jin-Ding; Chen, Yong-Chen; Chou, Yu-Ching

    2012-01-01

    The purposes of the present study were to describe the longitudinal utilization rates of participation in early intervention services of children with developmental delays, and to examine the geographical difference of services in this vulnerable population. We analyzed service utilization of the developmentally delayed children based on data of…

  5. A combined method to quantify the retinal metabolic rate of oxygen using photoacoustic ophthalmoscopy and optical coherence tomography

    PubMed Central

    Song, Wei; Wei, Qing; Liu, Wenzhong; Liu, Tan; Yi, Ji; Sheibani, Nader; Fawzi, Amani A.; Linsenmeier, Robert A.; Jiao, Shuliang; Zhang, Hao F.

    2014-01-01

    Quantitatively determining physiological parameters at a microscopic level in the retina furthers the understanding of the molecular pathways of blinding diseases, such as diabetic retinopathy and glaucoma. An essential parameter, which has yet to be quantified noninvasively, is the retinal oxygen metabolic rate (rMRO2). Quantifying rMRO2 is challenging because two parameters, the blood flow rate and hemoglobin oxygen saturation (sO2), must be measured together. We combined photoacoustic ophthalmoscopy (PAOM) with spectral domain-optical coherence tomography (SD-OCT) to tackle this challenge, in which PAOM measured the sO2 and SD-OCT mapped the blood flow rate. We tested the integrated system on normal wild-type rats, in which the measured rMRO2 was 297.86 ± 70.23 nl/minute. This quantitative method may shed new light on both fundamental research and clinical care in ophthalmology in the future. PMID:25283870

  6. Interaction of root nodule size and oxygen pressure on the rate of nitrogen fixation by cowpea and peanut

    SciTech Connect

    Sen, D.; Weaver, R.W.

    1987-04-01

    Size and anatomical features of nodules influence the rate of O/sub 2/ diffusion into nodules. Availability of oxygen can be a limiting factor in nitrogen fixation. Larger nodules have thicker cortices and low surface to volume ratio leading to lower rates of gaseous diffusion. Increased oxygen pressure in the environment alters the rate of nitrogen fixation but the rate of change may depend on the nodule size. This was investigated by measuring /sup 15/N/sub 2/ incorporation into nodules. Root nodules from 38 day old cowpea and peanut plants were collected and sorted into size groups having diameters of >3 mm, 2-3 mm, and just below 2 mm. Samples of each size group were enclosed in tubes and exposed to various combination of oxygen (8-28%) and /sup 15/N/sub 2/. With higher O/sub 2/ pressure all nodules showed increased N/sub 2/ fixation but the largest nodules showed the maximum increase. Specific activity of larger nodules was higher for N/sub 2/ fixation. For the sizes of nodules examined the largest nodules did not reflect any of the disadvantages of the large size but the benefits of higher rates of O/sub 2/ entry was evident.

  7. 40 CFR Table I-12 to Subpart I of... - Default Emission Factors (1-Uij) for Gas Utilization Rates (Uij) and By-Product Formation Rates...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Default Emission Factors (1-Uij) for Gas Utilization Rates (Uij) and By-Product Formation Rates (Bijk) for Semiconductor Manufacturing for... (Bijk) for Semiconductor Manufacturing for Use With the Stack Test Method (300 mm and 450 mm...

  8. 40 CFR Table I-11 to Subpart I of... - Default Emission Factors (1-Uij) for Gas Utilization Rates (Uij) and By-Product Formation Rates...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Default Emission Factors (1-Uij) for Gas Utilization Rates (Uij) and By-Product Formation Rates (Bijk) for Semiconductor Manufacturing for... (Bijk) for Semiconductor Manufacturing for Use With the Stack Test Method (150 mm and 200 mm...

  9. Evaluating free vs bound oxygen on ignition of nano-aluminum based energetics leads to a critical reaction rate criterion

    NASA Astrophysics Data System (ADS)

    Zhou, Wenbo; DeLisio, Jeffery B.; Wang, Xizheng; Egan, Garth C.; Zachariah, Michael R.

    2015-09-01

    This study investigates the ignition of nano-aluminum (n-Al) and n-Al based energetic materials (nanothermites) at varying O2 pressures (1-18 atm), aiming to differentiate the effects of free and bound oxygen on ignition and to assess if it is possible to identify a critical reaction condition for ignition independent of oxygen source. Ignition experiments were conducted by rapidly heating the samples on a fine Pt wire at a heating rate of ˜105 °C s-1 to determine the ignition time and temperature. The ignition temperature of n-Al was found to reduce as the O2 pressure increased, whereas the ignition temperatures of nanothermites (n-Al/Fe2O3, n-Al/Bi2O3, n-Al/K2SO4, and n-Al/K2S2O8) had different sensitivities to O2 pressure depending on the formulations. A phenomenological kinetic/transport model was evaluated to correlate the concentrations of oxygen both in condensed and gaseous phases, with the initiation rate of Al-O at ignition temperature. We found that a constant critical reaction rate (5 × 10-2 mol m-2 s-1) for ignition exists which is independent to ignition temperature, heating rate, and free vs bound oxygen. Since for both the thermite and the free O2 reaction the critical reaction rate for ignition is the same, the various ignition temperatures are simply reflecting the conditions when the critical reaction rate for thermal runaway is achieved.

  10. Utilization of negative beat-frequencies for maximizing the update-rate of OFDR

    NASA Astrophysics Data System (ADS)

    Gabai, Haniel; Botsev, Yakov; Hahami, Meir; Eyal, Avishay

    2015-07-01

    In traditional OFDR systems, the backscattered profile of a sensing fiber is inefficiently duplicated to the negative band of spectrum. In this work, we present a new OFDR design and algorithm that remove this redundancy and make use of negative beat frequencies. In contrary to conventional OFDR designs, it facilitates efficient use of the available system bandwidth and enables distributed sensing with the maximum allowable interrogation update-rate for a given fiber length. To enable the reconstruction of negative beat frequencies an I/Q type receiver is used. In this receiver, both the in-phase (I) and quadrature (Q) components of the backscatter field are detected. Following detection, both components are digitally combined to produce a complex backscatter signal. Accordingly, due to its asymmetric nature, the produced spectrum will not be corrupted by the appearance of negative beat-frequencies. Here, via a comprehensive computer simulation, we show that in contrast to conventional OFDR systems, I/Q OFDR can be operated at maximum interrogation update-rate for a given fiber length. In addition, we experimentally demonstrate, for the first time, the ability of I/Q OFDR to utilize negative beat-frequencies for long-range distributed sensing.

  11. Validity of using a 3-dimensional PET scanner during inhalation of 15O-labeled oxygen for quantitative assessment of regional metabolic rate of oxygen in man

    NASA Astrophysics Data System (ADS)

    Hori, Yuki; Hirano, Yoshiyuki; Koshino, Kazuhiro; Moriguchi, Tetsuaki; Iguchi, Satoshi; Yamamoto, Akihide; Enmi, Junichiro; Kawashima, Hidekazu; Zeniya, Tsutomu; Morita, Naomi; Nakagawara, Jyoji; Casey, Michael E.; Iida, Hidehiro

    2014-09-01

    Use of 15O labeled oxygen (15O2) and positron emission tomography (PET) allows quantitative assessment of the regional metabolic rate of oxygen (CMRO2) in vivo, which is essential to understanding the pathological status of patients with cerebral vascular and neurological disorders. The method has, however, been challenging, when a 3D PET scanner is employed, largely attributed to the presence of gaseous radioactivity in the trachea and the inhalation system, which results in a large amount of scatter and random events in the PET assessment. The present study was intended to evaluate the adequacy of using a recently available commercial 3D PET scanner in the assessment of regional cerebral radioactivity distribution during an inhalation of 15O2. Systematic experiments were carried out on a brain phantom. Experiments were also performed on a healthy volunteer following a recently developed protocol for simultaneous assessment of CMRO2 and cerebral blood flow, which involves sequential administration of 15O2 and C15O2. A particular intention was to evaluate the adequacy of the scatter-correction procedures. The phantom experiment demonstrated that errors were within 3% at the practically maximum radioactivity in the face mask, with the greatest radioactivity in the lung. The volunteer experiment demonstrated that the counting rate was at peak during the 15O gas inhalation period, within a verified range. Tomographic images represented good quality over the entire FOV, including the lower part of the cerebral structures and the carotid artery regions. The scatter-correction procedures appeared to be important, particularly in the process to compensate for the scatter originating outside the FOV. Reconstructed images dramatically changed if the correction was carried out using inappropriate procedures. This study demonstrated that accurate reconstruction could be obtained when the scatter compensation was appropriately carried out. This study also suggested the

  12. Monitoring cerebral oxygen saturation during cardiopulmonary bypass using near-infrared spectroscopy: the relationships with body temperature and perfusion rate

    NASA Astrophysics Data System (ADS)

    Teng, Yichao; Ding, HaiShu; Gong, Qingcheng; Jia, Zaishen; Huang, Lan

    2006-03-01

    During cardiopulmonary bypass (CPB) because of weak arterial pulsation, near-IR spectroscopy (NIRS) is almost the only available method to monitor cerebral oxygenation noninvasively. Our group develops a NIRS oximeter to monitor regional cerebral oxygenation especially its oxygen saturation (rScO2). To achieve optimal coupling between the sensor and human brain, the distances between the light source and the detectors on it are properly chosen. The oximeter is calibrated by blood gas analysis, and the results indicate that its algorithm is little influenced by either background absorption or overlying tissue. We used it to measure the rScO2 of 15 patients during CPB. It is shown that rScO2 is negatively correlated with body temperature and positively with perfusion rate. There are two critical stages during CPB when rScO2 might be relatively low: one is the low-perfusion-rate stage, the other is the early rewarming stage. During cooling, the changes of total hemoglobin concentration (CtHb) compared with its original value is also monitored. It is shown that CtHb decreases to a small extent, which may mainly reflect cerebral vasoconstriction induced by cooling. All these results indicate that NIRS can be used to monitor cerebral oxygenation to protect cerebral tissue during CPB.

  13. Rates of utilization of glucose, glutamine and oleate and formation of end-products by mouse peritoneal macrophages in culture.

    PubMed Central

    Newsholme, P; Newsholme, E A

    1989-01-01

    1. The metabolism of mouse thioglycollate-elicited peritoneal macrophages was studied in culture for up to 96 h. 2. The rates of glycolysis, lactate formation and glutamine utilization were approximately linear with time for at least 80 h of culture. 3. The rates of glucose and glutamine utilization by cultured macrophages were approx. 500 and 90 nmol/h per mg of protein respectively. This rate of glucose utilization is at least 50% greater than that previously reported for macrophages during 60 min incubation in a shaking flask; and it is now increased by addition of glutamine to the culture medium. The rate of glutamine utilization in culture is similar to that previously reported for macrophages during 60 min incubation. The major end-product of glucose metabolism is lactate, and those of glutamine metabolism are CO2, glutamate, ammonia and alanine. 4. Oleate was utilized by these cells: 14C from [14C]oleate was incorporated into CO2 and cellular lipid. The highest rate of oleate utilization was observed when both glucose and glutamine were present in the culture medium. The presence of oleate in the culture medium did not affect the rates of utilization of either glucose or glutamine. Of the [14C]oleate incorporated into lipid, approx. 80% was incorporated into triacylglycerol and only 18% into phospholipid. 5. The turnover rate for the total ATP content of the macrophage in culture is about 10 times per minute: the value for the perfused isolated maximally working rat heart is 22. This indicates a high metabolic rate for macrophages, and consequently emphasizes the importance of the provision of fuels for their function in an immune response. PMID:2775207

  14. Oxygen uptake and heart rate response of 6 standardized tennis drills.

    PubMed

    Bekraoui, Nabyl; Fargeas-Gluck, Marie-Agnès; Léger, Luc

    2012-10-01

    The purpose of this study was to compare the oxygen uptake of various on-court tennis drills. Eleven tennis players were monitored with a portable metabolic device to measure oxygen uptake of 6 different tennis drills at low and high speeds. The 6 drills were done with or without striking the ball, over half or full-width of the court, in attack or defense mode, using forehand or backhand strokes. Oxygen uptake values (mean ± SD) ranged from 33.8 ± 4.2 to 42.3 ± 5.1 mL·kg⁻¹·min⁻¹ when running at low speed on the full-width court in defense mode without striking the ball and when running at high speed on the full-width court in attack mode while striking the ball, respectively. Specific differences were observed. Attacking mode requires 6.5% more energy than defensive playing mode. Backhand strokes demand 7% more energy at low speed than forehand ones. Running and striking the ball costs 10% more energy than running without striking the ball. While striking the ball, shuttle running on half-width court costs 14% more energy than running on full-width courts. The specificity of the oxygen uptake responses obtained for these various tennis drills gives an improved representation of their energy cost and could be used to optimize training loads. PMID:22871149

  15. Routine Metabolic Rate and Limiting Oxygen Concentration of Freshwater Prawn Macrobrachium rosenbergii Larvae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Malaysian prawns, Macrobrachium rosenbergii, are hatched and raised indoors in small tanks. Prawns may be raised and shipped at high densities which could result in low dissolved oxygen (DO) conditions. Because DO may play an important role in prawn development and survival, we measured routine me...

  16. The Utility of Maze Accurate Response Rate in Assessing Reading Comprehension in Upper Elementary and Middle School Students

    ERIC Educational Resources Information Center

    McCane-Bowling, Sara J.; Strait, Andrea D.; Guess, Pamela E.; Wiedo, Jennifer R.; Muncie, Eric

    2014-01-01

    This study examined the predictive utility of five formative reading measures: words correct per minute, number of comprehension questions correct, reading comprehension rate, number of maze correct responses, and maze accurate response rate (MARR). Broad Reading cluster scores obtained via the Woodcock-Johnson III (WJ III) Tests of Achievement…

  17. Coolant-side heat-transfer rates for a hydrogen-oxygen rocket and a new technique for data correlation

    NASA Technical Reports Server (NTRS)

    Schacht, R. L.; Quentmeyer, R. J.

    1973-01-01

    An experimental investigation was conducted to determine the coolant-side, heat transfer coefficients for a liquid cooled, hydrogen-oxygen rocket thrust chamber. Heat transfer rates were determined from measurements of local hot gas wall temperature, local coolant temperature, and local coolant pressure. A correlation incorporating an integration technique for the transport properties needed near the pseudocritical temperature of liquid hydrogen gives a satisfactory prediction of hot gas wall temperatures.

  18. The Initial Rate of C Substrate Utilization and Longer-Term Soil C Storage

    SciTech Connect

    Smith, Jeff L.; Bell, Jennifer M.; Bolton, Harvey; Bailey, Vanessa L.

    2007-12-01

    Increasing soil C storage is viewed as a legitimate mechanism to offset current increases in atmospheric CO2 from anthropogenic sources. However, microbial transformation and turnover of soil carbon inputs will influence the magnitude of net soil C storage. The purpose of this study was to investigate several simple model C compounds to determine their decomposition rates in soil and the relationship between their initial decomposition rate and longer-term C sequestration. Pure 14C compounds of glucose, acetate, arginine, oxalate, phenylalanine and urea were incubated in soil for 125 days at 24 and 34oC. Respired 14CO2 and specific activity was quantitatively measured every day for 15 days and residual soil 14C after 125 days. At both temperatures, the percent 14C remaining in the soil after 125 days of incubation was positively and significantly correlated with the percent substrate utilized in the first day. For the two temperatures, the correlation of total 14CO2 and specific activity was significant (R2=.86,.78) as was the percent remaining after 125 days (C34oC = 0.75 x C24oC, R2 = 0.90). The 14C in the microbial biomass ranged from 4-15% after 15 days and declined through day 125 contributing significantly to the 14C evolved. Priming of 12C SOM was negative at day 3 but became positive, reaching a maximum on day 12, the total increase in soil C from substrates was greater than the primed C. The data support the concept that the more rapidly a substrate is initially mineralized the more persistent it will be in the soil.

  19. Electric Utility Rate Design Study: cost-benefit analysis of load-management options

    SciTech Connect

    Wood, A.J.

    1980-12-09

    This report summarizes the methodology used by Power Technologies, Inc. (PTI) and the staff of the Northern States Power Company (NSP) to develop the cost and cost-benefits of a potential load-management scheme for NSP. In this methodology costs are defined as the present value of the reverse required to install and operate the load-management system. The cost-benefit is the present value of the net change in all future revenue requirements for the entire electric power system after the proposed load-management plan is implemented. The load-management scheme used to illustrate the methodology involved the direct control of air conditioning, water heaters, and the use of storage heating for a fraction of the NSP load over the 15-year period from 1980 to 1995. The economic-analysis procedure used is identical to that practiced by system-planning engineers in electric utilities. The alteration of customers' load patterns by means of direct (or indirect) load management will affect all portions of the electric power system, the operating costs associated with supplying the load energy, and the revenues required to support the investment in facilities to meet the expected load growth. This study examines the altered-system expansion plans and resulting changes in costs. Included as a supplement is a Comments on evaluation of the PTI report by the Rate Design Study Advisory Group IV.

  20. Development of high capacity, high rate lithium ion batteries utilizing metal fiber conductive additives

    NASA Astrophysics Data System (ADS)

    Ahn, Soonho; Kim, Youngduk; Kim, Kyung Joon; Kim, Tae Hyung; Lee, Hyungkeun; Kim, Myung H.

    As lithium ion cells dominate the battery market, the performance improvement is an utmost concern among developers and researchers. Conductive additives are routinely employed to enhance electrode conductivity and capacity. Carbon particulates—graphite or carbon black powders—are conventional and popular choices as conductive fillers. However, percolation requirements of particles demand significant volumetric content of impalpable, and thereby high area conductive fillers. As might be expected, the electrode active surface area escalates unnecessarily, resulting in overall increase in reaction with electrolytes and organic solvents. The increased reactions usually manifest as an irreversible loss of anode capacity, gradual oxidation and consumption of electrolyte on the cathode—which causes capacity decline during cycling—and an increased threat to battery safety by gas evolution and exothermic solvent oxidation. In this work we have utilized high aspect ratio, flexible, micronic metal fibers as low active area and high conductivity additives. The metal fibers appear well dispersed within the electrode and to satisfy percolation requirements very efficiently at very low volumetric content compared to conventional carbon-based conductive additives. Results from 18650-type cells indicate significant enhancements in electrode capacity and high rate capability while the irreversible capacity loss is negligible.

  1. Circadian control of oscillations in mitochondrial rate-limiting enzymes and nutrient utilization by PERIOD proteins.

    PubMed

    Neufeld-Cohen, Adi; Robles, Maria S; Aviram, Rona; Manella, Gal; Adamovich, Yaarit; Ladeuix, Benjamin; Nir, Dana; Rousso-Noori, Liat; Kuperman, Yael; Golik, Marina; Mann, Matthias; Asher, Gad

    2016-03-22

    Mitochondria are major suppliers of cellular energy through nutrients oxidation. Little is known about the mechanisms that enable mitochondria to cope with changes in nutrient supply and energy demand that naturally occur throughout the day. To address this question, we applied MS-based quantitative proteomics on isolated mitochondria from mice killed throughout the day and identified extensive oscillations in the mitochondrial proteome. Remarkably, the majority of cycling mitochondrial proteins peaked during the early light phase. We found that rate-limiting mitochondrial enzymes that process lipids and carbohydrates accumulate in a diurnal manner and are dependent on the clock proteins PER1/2. In this conjuncture, we uncovered daily oscillations in mitochondrial respiration that peak during different times of the day in response to different nutrients. Notably, the diurnal regulation of mitochondrial respiration was blunted in mice lacking PER1/2 or on a high-fat diet. We propose that PERIOD proteins optimize mitochondrial metabolism to daily changes in energy supply/demand and thereby, serve as a rheostat for mitochondrial nutrient utilization. PMID:26862173

  2. Ventilation rates and activity levels of juvenile jumbo squid under metabolic suppression in the oxygen minimum zone.

    PubMed

    Trübenbach, Katja; Pegado, Maria R; Seibel, Brad A; Rosa, Rui

    2013-02-01

    The Humboldt (jumbo) squid, Dosidicus gigas, is a part-time resident of the permanent oxygen minimum zone (OMZ) in the Eastern Tropical Pacific and, thereby, it encounters oxygen levels below its critical oxygen partial pressure. To better understand the ventilatory mechanisms that accompany the process of metabolic suppression in these top oceanic predators, we exposed juvenile D. gigas to the oxygen levels found in the OMZ (1% O(2), 1 kPa, 10 °C) and measured metabolic rate, activity cycling patterns, swimming mode, escape jet (burst) frequency, mantle contraction frequency and strength, stroke volume and oxygen extraction efficiency. In normoxia, metabolic rate varied between 14 and 29 μmol O(2) g(-1) wet mass h(-1), depending on the level of activity. The mantle contraction frequency and strength were linearly correlated and increased significantly with activity level. Additionally, an increase in stroke volume and ventilatory volume per minute was observed, followed by a mantle hyperinflation process during high activity periods. Squid metabolic rate dropped more than 75% during exposure to hypoxia. Maximum metabolic rate was not achieved under such conditions and the metabolic scope was significantly decreased. Hypoxia changed the relationship between mantle contraction strength and frequency from linear to polynomial with increasing activity, indicating that, under hypoxic conditions, the jumbo squid primarily increases the strength of mantle contraction and does not regulate its frequency. Under hypoxia, jumbo squid also showed a larger inflation period (reduced contraction frequency) and decreased relaxed mantle diameter (shortened diffusion pathway), which optimize oxygen extraction efficiency (up to 82%/34%, without/with consideration of 60% potential skin respiration). Additionally, they breathe 'deeply', with more powerful contractions and enhanced stroke volume. This deep-breathing behavior allows them to display a stable ventilatory volume per

  3. Outcome Rating Scale and Session Rating Scale in Psychological Practice: Clinical Utility of Ultra-Brief Measures

    ERIC Educational Resources Information Center

    Campbell, Alistair; Hemsley, Samantha

    2009-01-01

    The validity and reliability of the Outcome Rating Scale (ORS) and the Session Rating Scale (SRS) were evaluated against existing longer measures, including the Outcome Questionnaire-45, Working Alliance Inventory, Depression Anxiety Stress Scale-21, Quality of Life Scale, Rosenberg Self-Esteem Scale and General Self-efficacy Scale. The measures…

  4. Relationship of efficiency indices with performance, heart rate, oxygen consumption, blood parameters, and estimated heat production in Nellore steers.

    PubMed

    Chaves, A S; Nascimento, M L; Tullio, R R; Rosa, A N; Alencar, M M; Lanna, D P

    2015-10-01

    The objective of this study was to examine the relationship of efficiency indices with performance, heart rate, oxygen consumption, blood parameters, and estimated heat production (EHP) in Nellore steers. Eighteen steers were individually lot-fed diets of 2.7 Mcal ME/kg DM for 84 d. Estimated heat production was determined using oxygen pulse (OP) methodology, in which heart rate (HR) was monitored for 4 consecutive days. Oxygen pulse was obtained by simultaneously measuring HR and oxygen consumption during a 10- to 15-min period. Efficiency traits studied were feed efficiency (G:F) and residual feed intake (RFI) obtained by regression of DMI in relation to ADG and midtest metabolic BW (RFI). Alternatively, RFI was also obtained based on equations reported by the NRC's to estimate individual requirement and DMI (RFI calculated by the NRC [1996] equation [RFI]). The slope of the regression equation and its significance was used to evaluate the effect of efficiency indices (RFI, RFI, or G:F) on the traits studied. A mixed model was used considering RFI, RFI, or G:F and pen type as fixed effects and initial age as a covariate. For HR and EHP variables, day was included as a random effect. There was no relationship between efficiency indices and back fat depth measured by ultrasound or daily HR and EHP ( > 0.05). Because G:F is obtained in relation to BW, the slope of G:F was positive and significant ( < 0.05). Regardless of the method used, efficient steers had lower DMI ( < 0.05). The initial LM area was indirectly related to RFI and RFI ( < 0.05); however, the final muscle area was related to only RFI. Oxygen consumption per beat was not related to G:F; however, it was lower for RFI- and RFI-efficient steers, and consequently, oxygen volume (mL·min·kg) and OP (μL O·beat·kg) were also lower ( < 0.05). Blood parameters were not related to RFI and RFI ( > 0.05); however, G:F-efficient steers showed lower hematocrit and hemoglobin concentrations ( < 0

  5. Monitoring the variations of the oxygen transfer rate in a full scale membrane bioreactor using daily mass balances.

    PubMed

    Racault, Y; Stricker, A-E; Husson, A; Gillot, S

    2011-01-01

    Oxygen transfer in biological wastewater treatment processes with high sludge concentration, such as membrane bioreactor (MBR), is an important issue. The variation of alpha-factor versus mixed liquor suspended solids (MLSS) concentration was investigated in a full scale MBR plant under process conditions, using mass balances. Exhaustive data from the Supervisory Control And Data Acquisition (SCADA) and from additional online sensors (COD, DO, MLSS) were used to calculate the daily oxygen consumption (OC) using a non-steady state mass balance for COD and total N on a 24-h basis. To close the oxygen balance, OC has to match the total oxygen transfer rate (OTRtot) of the system, which is provided by fine bubble (FB) diffusers in the aeration tank and coarse bubbles (CB) in separate membrane tanks. First assessing OTR(CB) then closing the balance OC = OTRtot allowed to calculate OTR(FB) and to fit an exponential relationship between OTR(FB) and MLSS. A comparison of the alpha-factor obtained by this balance method and by direct measurements with the off-gas method on the same plant is presented and discussed. PMID:22049761

  6. Tailoring deposition and morphology of discharge products towards high-rate and long-life lithium-oxygen batteries.

    PubMed

    Xu, Ji-Jing; Wang, Zhong-Li; Xu, Dan; Zhang, Lei-Lei; Zhang, Xin-Bo

    2013-01-01

    Lithium-oxygen batteries are an attractive technology for electrical energy storage because of their exceptionally high-energy density; however, battery applications still suffer from low rate capability, poor cycle stability and a shortage of stable electrolytes. Here we report design and synthesis of a free-standing honeycomb-like palladium-modified hollow spherical carbon deposited onto carbon paper, as a cathode for a lithium-oxygen battery. The battery is capable of operation with high-rate (5,900 mAh g ⁻¹ at a current density of 1.5 A g⁻¹) and long-term (100 cycles at a current density of 300 mA g⁻¹ and a specific capacity limit of 1,000 mAh g⁻¹). These properties are explained by the tailored deposition and morphology of the discharge products as well as the alleviated electrolyte decomposition compared with the conventional carbon cathodes. The encouraging performance also offers hope to design more advanced cathode architectures for lithium-oxygen batteries. PMID:24052126

  7. [Dynamics simulation on plant growth, N accumulation and utilization of processing tomato at different N fertilization rates].

    PubMed

    Wang, Xin; Ma, Fu-Yu; Diao, Ming; Fan, Huam; Cui, Jing; Jia, Biao; He, Hai-Bing; Liu, Qi

    2014-04-01

    Three field experiments were conducted to simulate the dynamics of aboveground biomass, N accumulation and utilization of drip-irrigated processing tomatoes at different N fertilization rates (0, 75, 150, 300, 450, or 600 kg x hm(-2)). The results showed that Logistic models best described the changes in aboveground biomass, N accumulation, and utilization of accumulated N efficiency with the physiological development time (PDT). Rapid accumulation of N began about 4-6 d (PDT) earlier than the rapid accumulation of aboveground biomass. The momentary utilization rate of N (NMUR) increased after emergence, reached a single peak, and then decreased. The N accumulation, aboveground biomass and yield were highest in the 300 kg x hm(-2) treatment. The quadratic model indicated that application rate of 349 to 382 kg N x hm(-2) was optimum for drip-irrigated processing tomatoes in northern Xinjiang. PMID:25011297

  8. Regional oxygen reduction and denitrification rates in groundwater from multi-model residence time distributions, San Joaquin Valley, USA

    USGS Publications Warehouse

    Green, Christopher T.; Jurgens, Bryant; Zhang, Yong; Starn, Jeffrey; Singleton, Michael J.; Esser, Bradley K.

    2016-01-01

    Rates of oxygen and nitrate reduction are key factors in determining the chemical evolution of groundwater. Little is known about how these rates vary and covary in regional groundwater settings, as few studies have focused on regional datasets with multiple tracers and methods of analysis that account for effects of mixed residence times on apparent reaction rates. This study provides insight into the characteristics of residence times and rates of O2 reduction and denitrification (NO3− reduction) by comparing reaction rates using multi-model analytical residence time distributions (RTDs) applied to a data set of atmospheric tracers of groundwater age and geochemical data from 141 well samples in the Central Eastern San Joaquin Valley, CA. The RTD approach accounts for mixtures of residence times in a single sample to provide estimates of in-situ rates. Tracers included SF6, CFCs, 3H, He from 3H (tritiogenic He),14C, and terrigenic He. Parameter estimation and multi-model averaging were used to establish RTDs with lower error variances than those produced by individual RTD models. The set of multi-model RTDs was used in combination with NO3− and dissolved gas data to estimate zero order and first order rates of O2 reduction and denitrification. Results indicated that O2 reduction and denitrification rates followed approximately log-normal distributions. Rates of O2 and NO3− reduction were correlated and, on an electron milliequivalent basis, denitrification rates tended to exceed O2 reduction rates. Estimated historical NO3− trends were similar to historical measurements. Results show that the multi-model approach can improve estimation of age distributions, and that relatively easily measured O2 rates can provide information about trends in denitrification rates, which are more difficult to estimate.

  9. Impact of oxygen concentrations on fertilization, cleavage, implantation, and pregnancy rates of in vitro generated human embryos

    PubMed Central

    Peng, Zhao-Feng; Shi, Sen-Lin; Jin, Hai-Xia; Yao, Gui-Dong; Wang, En-Yin; Yang, Hong-Yi; Song, Wen-Yan; Sun, Ying-Pu

    2015-01-01

    The aim of the present study was to determine the impact of oxygen concentration during in vitro culture of human oocytes and embryos on fertilization, cleavage, implantation, pregnancy, multiple gestation and abortion rates. Women 20-48 years old presenting for infertility treatment and accounting for 3484 in vitro fertilization/intracytoplasmic sperm injection cycles were included in the study. Oocytes/embryos were randomly allocated to be incubated under three different oxygen tension environments: (1) 20% O2 in air; (2) initially 20% O2 in air, followed on day 2 (2-4 cells stage) by 5% CO2, 5% O2 and 90% N2; and (3) 5% CO2, 5% O2 and 90% N2 throughout. Interestingly, IVF-derived embryos cultured in 5% O2 yielded higher rates of fertilization and implantation as compared to those incubated in 20% O2 (P < 0.05). Conversely, embryos in 20% O2 yielded higher rates of fertilization, high quality embryo and implantation than those in the 20%-5% O2 group (P < 0.05). Moreover, ICSI-derived embryos cultured in 20% O2 resulted in lower rates of cleavage as compared to those from the 20%-5% O2 group (P < 0.05). These results are consistent with in vitro and subsequent in vivo embryo development being more susceptible to O2 tension fluctuations rather than the degree of O2 tension itself during culture. PMID:26131222

  10. Fermentation process using specific oxygen uptake rates as a process control

    SciTech Connect

    Van Hoek, Pim; Aristidou, Aristos; Rush, Brian

    2011-05-10

    Specific oxygen uptake (OUR) is used as a process control parameter in fermentation processes. OUR is determined during at least the production phase of a fermentation process, and process parameters are adjusted to maintain the OUR within desired ranges. The invention is particularly applicable when the fermentation is conducted using a microorganism having a natural PDC pathway that has been disrupted so that it no longer functions. Microorganisms of this sort often produce poorly under strictly anaerobic conditions. Microaeration controlled by monitoring OUR allows the performance of the microorganism to be optimized.

  11. Fermentation process using specific oxygen uptake rates as a process control

    SciTech Connect

    Van Hoek; Pim , Aristidou; Aristos , Rush; Brian

    2007-06-19

    Specific oxygen uptake (OUR) is used as a process control parameter in fermentation processes. OUR is determined during at least the production phase of a fermentation process, and process parameters are adjusted to maintain the OUR within desired ranges. The invention is particularly applicable when the fermentation is conducted using a microorganism having a natural PDC pathway that has been disrupted so that it no longer functions. Microorganisms of this sort often produce poorly under strictly anaerobic conditions. Microaeration controlled by monitoring OUR allows the performance of the microorganism to be optimized.

  12. Fermentation process using specific oxygen uptake rates as a process control

    SciTech Connect

    Van Hoek, Pim; Aristidou, Aristos; Rush, Brian

    2014-09-09

    Specific oxygen uptake (OUR) is used as a process control parameter in fermentation processes. OUR is determined during at least the production phase of a fermentation process, and process parameters are adjusted to maintain the OUR within desired ranges. The invention is particularly applicable when the fermentation is conducted using a microorganism having a natural PDC pathway that has been disrupted so that it no longer functions. Microorganisms of this sort often produce poorly under strictly anaerobic conditions. Microaeration controlled by monitoring OUR allows the performance of the microorganism to be optimized.

  13. Fermentation process using specific oxygen uptake rates as a process control

    DOEpatents

    Van Hoek, Pim; Aristidou, Aristos; Rush, Brian J.

    2016-08-30

    Specific oxygen uptake (OUR) is used as a process control parameter in fermentation processes. OUR is determined during at least the production phase of a fermentation process, and process parameters are adjusted to maintain the OUR within desired ranges. The invention is particularly applicable when the fermentation is conducted using a microorganism having a natural PDC pathway that has been disrupted so that it no longer functions. Microorganisms of this sort often produce poorly under strictly anaerobic conditions. Microaeration controlled by monitoring OUR allows the performance of the microorganism to be optimized.

  14. Substantial energy expenditure for locomotion in ciliates verified by means of simultaneous measurement of oxygen consumption rate and swimming speed.

    PubMed

    Katsu-Kimura, Yumiko; Nakaya, Fumio; Baba, Shoji A; Mogami, Yoshihiro

    2009-06-01

    In order to characterize the energy expenditure of Paramecium, we simultaneously measured the oxygen consumption rate, using an optic fluorescence oxygen sensor, and the swimming speed, which was evaluated by the optical slice method. The standard metabolic rate (SMR, the rate of energy consumption exclusively for physiological activities other than locomotion) was estimated to be 1.18x10(-6) J h(-1) cell(-1) by extrapolating the oxygen consumption rate into one at zero swimming speed. It was about 30% of the total energy consumed by the cell swimming at a mean speed of 1 mm s(-1), indicating that a large amount of the metabolic energy (about 70% of the total) is consumed for propulsive activity only. The mechanical power liberated to the environment by swimming Paramecium was calculated on the basis of Stokes' law. This power, termed Stokes power, was 2.2x10(-9) J h(-1) cell(-1), indicating extremely low efficiency (0.078%) in the conversion of metabolic power to propulsion. Analysis of the cost of transport (COT, the energy expenditure for translocation per units of mass and distance) revealed that the efficiency of energy expenditure in swimming increases with speed rather than having an optimum value within a wide range of forced swimming, as is generally found in fish swimming. These characteristics of energy expenditure would be unique to microorganisms, including Paramecium, living in a viscous environment where large dissipation of the kinetic energy is inevitable due to the interaction with the surrounding water. PMID:19482999

  15. Charging/Discharging Nanomorphology Asymmetry and Rate-Dependent Capacity Degradation in Li-Oxygen Battery.

    PubMed

    Kushima, Akihiro; Koido, Tetsuya; Fujiwara, Yoshiya; Kuriyama, Nariaki; Kusumi, Nobuhiro; Li, Ju

    2015-12-01

    Liquid-cell in situ transmission electron microscopy (TEM) observations of the charge/discharge reactions of nonaqueous Li-oxygen battery cathode were performed with ∼5 nm spatial resolution. The discharging reaction occurred at the interface between the electrolyte and the reaction product, whereas in charging, the reactant was decomposed at the contact with the gold current collector, indicating that the lithium ion diffusivity/electronic conductivity is the limiting factor in discharging/charging, respectively, which is a root cause for the asymmetry in discharging/charging overpotential. Detachments of lithium oxide particles from the current collector into the liquid electrolyte are frequently seen when the cell was discharged at high overpotentials, with loss of active materials into liquid electrolyte ("flotsam") under minute liquid flow agitation, as the lithium peroxide dendritic trees are shown to be fragile mechanically and electrically. Our result implies that enhancing the binding force between the reaction products and the current collector to maintain robust electronic conduction is a key for improving the battery performance. This work demonstrated for the first time the in situ TEM observation of a three-phase-reaction involving gold electrode, lithium oxides, DMSO electrolyte and lithium salt, and O2 gas. The technique described in this work is not limited to Li-oxygen battery but also can be potentially used in other applications involving gas/liquid/solid electrochemical reactions. PMID:26535921

  16. The relationship between oxygen consumption rate and viability of in vivo-derived pig embryos vitrified by the micro volume air cooling method.

    PubMed

    Sakagami, N; Nishida, K; Misumi, K; Hirayama, Y; Yamashita, S; Hoshi, H; Misawa, H; Akiyama, K; Suzuki, C; Yoshioka, K

    2016-01-01

    The aim of this study was to assess the viability of vitrified-warmed in vivo-derived pig embryos after measuring the oxygen consumption rate. Six days after artificial insemination, blastocysts were collected from gilts and vitrified by the micro volume air cooling method. The oxygen consumption rate was measured in 60 vitrified-warmed embryos, which were then cultured for 48h to assess the viability. The survival (re-expansion) rate of embryos after warming was 85.0%. The average oxygen consumption rate of embryos immediately after warming was greater in embryos which could re-expand during subsequent culture (F=0.75±0.04) than that in those which failed to re-expand (F=0.33±0.05). Moreover, the oxygen consumption rate of vitrified-warmed embryos was greater in the hatched (F=0.88±0.06) than that in the not-hatched group (F=0.53±0.04). When the oxygen consumption rate of the vitrified-warmed embryos and the numbers of viable and dead cells in embryos were determined, there was a positive correlation between the oxygen consumption rate and the number of live cells (P<0.01, r=0.538). A total of 29 vitrified embryos after warming and measuring the oxygen consumption rate were surgically transferred into uterine horns of two recipients. Both of the recipients become pregnant and farrowed 12 healthy piglets. These results demonstrate that the oxygen consumption rate of vitrified-warmed pig embryos can be related to the number of live cells and that the measurement of oxygen consumption of embryos after cryopreservation may be useful for estimating embryo survivability. PMID:26642748

  17. Rate constants for the reactions of free radicals with oxygen in solution

    SciTech Connect

    Maillard, B.; Ingold, K.U.; Scaiano, J.C.

    1983-07-27

    The kinetics of the rections of several free radicals with oxygen have been examined in solution at 300 K using laser flash photolysis techniques. The reactions of resonance-stabilized radicals are only slightly slower than those of nonstabilized radicals: for example, for tert-butyl (in cyclohexane), 4.93 x 10/sup 9/; benzyl, 2.36 x 10/sup 9/ (in cyclohexane); cyclohexadienyl (in benzene), 1.64 x 10/sup 9/ M/sup -1/ s/sup -1/. The reaction of butyl-tin (n-Bu/sub 3/Sn.) radicals is unusually fast (7.5 x 10/sup 9/ M/sup -1/ s/sup -1/), a fact that has been tentatively attributed to a relaxation of spin selection rules due to heavy atom effects. 1 table.

  18. Impacts of Western Area Power Administration`s power marketing alternatives on retail electricity rates and utility financial viability

    SciTech Connect

    Bodmer, E.; Fisher, R.E.; Hemphill, R.C.

    1995-03-01

    Changes in power contract terms for customers of Western`s Salt Lake City Area Office affect electricity rates for consumers of electric power in Arizona, Colorado, Nevada, New Mexico, Utah, and Wyoming. The impacts of electricity rate changes on consumers are studied by measuring impacts on the rates charged by individual utility systems, determining the average rates in regional areas, and conducting a detailed rate analysis of representative utility systems. The primary focus is an evaluation of the way retail electricity rates for Western`s preference customers vary with alternative pricing and power quantity commitment terms under Western`s long-term contracts to sell power (marketing programs). Retail rate impacts are emphasized because changes in the price of electricity are the most direct economic effect on businesses and residences arising from different Western contractual and operational policies. Retail rates are the mechanism by which changes in cost associated with Western`s contract terms are imposed on ultimate consumers, and rate changes determine the dollar level of payments for electric power incurred by the affected consumers. 41 figs., 9 tabs.

  19. Frequency and trajectory of abnormalities in respiratory rate, temperature and oxygen saturation in severe pneumonia in children.

    PubMed

    Izadnegahdar, Rasa; Fox, Matthew P; Thea, Donald M; Qazi, Shamim A

    2012-08-01

    The frequency or trajectory of vital sign abnormalities in children with pneumonia has not been described. In a cohort of 2714 patients with severe pneumonia identified and treated as per the World Health Organization definition and recommendations, tachypnea, fever and hypoxia were found in 68.9%, 23.6% and 15.5% of children, respectively. Median oxygen saturation returned to a normal range by 10 hours following initiation of treatment, followed by temperature at 12 hours and respiratory rate at 22 hours for subjects <12 months and at 48 hours for those ≥ 12 months of age. PMID:22531236

  20. Quantifying the cerebral metabolic rate of oxygen by combining diffuse correlation spectroscopy and time-resolved near-infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Verdecchia, Kyle; Diop, Mamadou; Lee, Ting-Yim; St. Lawrence, Keith

    2013-02-01

    Preterm infants are highly susceptible to ischemic brain injury; consequently, continuous bedside monitoring to detect ischemia before irreversible damage occurs would improve patient outcome. In addition to monitoring cerebral blood flow (CBF), assessing the cerebral metabolic rate of oxygen (CMRO2) would be beneficial considering that metabolic thresholds can be used to evaluate tissue viability. The purpose of this study was to demonstrate that changes in absolute CMRO2 could be measured by combining diffuse correlation spectroscopy (DCS) with time-resolved near-infrared spectroscopy (TR-NIRS). Absolute CBF was determined using bolus-tracking TR-NIRS to calibrate the DCS measurements. Cerebral venous blood oxygenation (SvO2) was determined by multiwavelength TR-NIRS measurements, the accuracy of which was assessed by directly measuring the oxygenation of sagittal sinus blood. In eight newborn piglets, CMRO2 was manipulated by varying the anesthetics and by injecting sodium cyanide. No significant differences were found between the two sets of SvO2 measurements obtained by TR-NIRS or sagittal sinus blood samples and the corresponding CMRO2 measurements. Bland-Altman analysis showed a mean CMRO2 difference of 0.0268±0.8340 mL O2/100 g/min between the two techniques over a range from 0.3 to 4 mL O2/100 g/min.

  1. Measurement of OH(X 2Πi υ = 2, 3, 4) Collisional Removal Rate Constants by Oxygen Atoms

    NASA Astrophysics Data System (ADS)

    Boulter, J. E.; Marschall, J.; Copeland, R. A.

    2002-05-01

    The fluorescence of vibrationally excited, ground electronic state hydroxyl radical (OH) in the airglow originates in the mesosphere-lower thermosphere (MLT) region of Earth's atmosphere. Spectroscopic measurements of this infrared emission are being made by the TIMED satellite to characterize the dynamics, temperature profiles, and HOy chemistry in the region 80-100 km. In the atmosphere, hydroxyl radicals in υ = 6-9 are formed in the reaction of hydrogen atoms with ozone; lower vibrational levels are populated through subsequent collisional deactivation by molecular oxygen. The lifetimes of the lower levels (υ <= 4) are significantly affected by collisions with atomic oxygen, as collisions with molecular oxygen are less efficient at relaxation than at higher levels. Given the importance of O-atom collisions in the atmosphere, we have developed an experimental approach and performed experiments on the collisional removal of OH(υ = 2, 3, 4) by atomic oxygen. In this work, the reaction of OH with atomic oxygen is studied using a two-laser method. Ozone is photolyzed in nitrogen with a pulsed excimer laser to generate O(1D), a portion of which reacts with either hydrogen to form OH(υ <= 4) or with water vapor to form OH(υ <= 3); the remainder is rapidly deactivated by collisions with N2 to produce ground state O(3P). A second, tunable dye laser pulse probes the OH population in a specific rovibrational state as a function of reaction time, using fluorescence from the A 2}Σ {+ - X 2Π { i} system. By adjusting the composition of the reactant gas mixture and by varying the photolysis laser fluence to control the ozone dissociation fraction, the dominant relaxation partner can be varied systematically from ozone and water or hydrogen to atomic oxygen. Experimentally determined rate constants for the removal of OH(υ = 2, 3, 4) by O(3P) are obtained at room temperature, with values of 6 x 10-11, 1.0 x 10-10 and 1.6 x 10-10 for υ = 2, 3 and 4, respectively, and 2-

  2. Utilization Rate and Presenting Concerns of International Students at a University Counseling Center: Implications for Outreach Programming

    ERIC Educational Resources Information Center

    Nilsson, Johanna E.; Berkel, Laverne A.; Flores, Lisa Y.; Lucas, Margaretha S.

    2004-01-01

    This study sought to understand the utilization rates and presenting concerns of international students in order to identify relevant topics for outreach programming. We examined the presenting concerns of all international students (n= 41) who sought counseling at a university counseling center during an academic year. The results indicated that…

  3. Rating Health and Social Indicators for Use with Indigenous Communities: A Tool for Balancing Cultural and Scientific Utility

    ERIC Educational Resources Information Center

    Daniel, Mark; Cargo, Margaret; Marks, Elisabeth; Paquet, Catherine; Simmons, David; Williams, Margaret; Rowley, Kevin; O'Dea, Kerin

    2009-01-01

    This study reports on the development and evaluation of a rating tool to assess the scientific utility and cultural appropriateness of community-level indicators for application with Indigenous populations. Indicator criteria proposed by the U.S. Institute of Medicine were culturally adapted through reviewing the literature and consultations with…

  4. Deep-sea echinoderm oxygen consumption rates and an interclass comparison of metabolic rates in Asteroidea, Crinoidea, Echinoidea, Holothuroidea and Ophiuroidea.

    PubMed

    Hughes, Sarah Jane Murty; Ruhl, Henry A; Hawkins, Lawrence E; Hauton, Chris; Boorman, Ben; Billett, David S M

    2011-08-01

    Echinoderms are important components of deep-sea communities because of their abundance and the fact that their activities contribute to carbon cycling. Estimating the echinoderm contribution to food webs and carbon cycling is important to our understanding of the functioning of the deep-sea environment and how this may alter in the future as climatic changes take place. Metabolic rate data from deep-sea echinoderm species are, however, scarce. To obtain such data from abyssal echinoderms, a novel in situ respirometer system, the benthic incubation chamber system (BICS), was deployed by remotely operated vehicle (ROV) at depths ranging from 2200 to 3600 m. Oxygen consumption rates were obtained in situ from four species of abyssal echinoderm (Ophiuroidea and Holothuroidea). The design and operation of two versions of BICS are presented here, together with the in situ respirometry measurements. These results were then incorporated into a larger echinoderm metabolic rate data set, which included the metabolic rates of 84 echinoderm species from all five classes (Asteroidea, Crinoidea, Echinoidea, Holothuroidea and Ophiuroidea). The allometric scaling relationships between metabolic rate and body mass derived in this study for each echinoderm class were found to vary. Analysis of the data set indicated no change in echinoderm metabolic rate with depth (by class or phylum). The allometric scaling relationships presented here provide updated information for mass-dependent deep-sea echinoderm metabolic rate for use in ecosystem models, which will contribute to the study of both shallow water and deep-sea ecosystem functioning and biogeochemistry. PMID:21753044

  5. Rate of recombination of oxygen atoms and CO at temperatures below ambient

    NASA Technical Reports Server (NTRS)

    Inn, E. C. Y.

    1974-01-01

    The measurements reported were conducted with 30.0 torr CO, 40.0 torr argon, and varying amounts of carbon dioxide from about 20 to 230 torr. Measurements were made at 277, 272, 263, and 257 K. The pseudo-first-order decay rate as a function of carbon dioxide pressure is shown in a graph. An Arrhenius plot for the rate constants obtained from the measurements is also presented. A value for the activation energy was determined on the basis of a linear least-squares fit to the data.

  6. Effects of dissolved oxygen and pH on nitrous oxide production rates in autotrophic partial nitrification granules.

    PubMed

    Rathnayake, Rathnayake M L D; Oshiki, Mamoru; Ishii, Satoshi; Segawa, Takahiro; Satoh, Hisashi; Okabe, Satoshi

    2015-12-01

    The effects of dissolved oxygen (DO) and pH on nitrous oxide (N2O) production rates and pathways in autotrophic partial nitrification (PN) granules were investigated at the granular level. N2O was primarily produced by betaproteobacterial ammonia-oxidizing bacteria, mainly Nitrosomonas europaea, in the oxic surface layer (<200μm) of the autotrophic PN granules. N2O production increased with increasing bulk DO concentration owing to activation of the ammonia (i.e., hydroxylamine) oxidation in this layer. The highest N2O emissions were observed at pH 7.5, although the ammonia oxidation rate was unchanged between pH 6.5 and 8.5. Overall, the results of this study suggest that in situ analyses of PN granules are essential to gaining insight into N2O emission mechanisms in a granule. PMID:26318242

  7. Biomass characterization by dielectric monitoring of viability and oxygen uptake rate measurements in a novel membrane bioreactor.

    PubMed

    Shariati, Farshid Pajoum; Heran, Marc; Sarrafzadeh, Mohammad Hossein; Mehrnia, Mohammad Reza; Sarzana, Gabriele; Ghommidh, Charles; Grasmick, Alain

    2013-07-01

    The application of permittivity and oxygen uptake rate (OUR) as biological process control parameters in a wastewater treatment system was evaluated. Experiments were carried out in a novel airlift oxidation ditch membrane bioreactor under different organic loading rates (OLR). Permittivity as representative of activated sludge viability was measured by a capacitive on-line sensor. OUR was also measured as a representative for respirometric activity. Results showed that the biomass concentration increases with OLR and all biomass related measurements and simulators such as MLSS, permittivity, OUR, ASM1 and ASM3 almost follow the same increasing trends. The viability of biomass decreased when the OLR was reduced from 5 to 4 kg COD m(-3)d(-1). During decreasing of OLR, biomass related parameters generally decreased but not in a similar manner. Also, protein concentration in the system during OLR decreasing changed inversely with the activated sludge viability. PMID:23708851

  8. Direct rate constant measurements for the reaction of ground-state atomic oxygen with ethylene, 244-1052 K

    SciTech Connect

    Klemm, R.B.; Nesbitt, F.L.; Skolnik, E.G.; Lee, J.H.; Smalley, J.F.

    1987-03-12

    The rate constant for the reaction of ground-state atomic oxygen with ethylene was determined by using two techniques: flash photolysis-resonance fluorescence (FP-RF, 244-1052 K) and discharge flow-resonance fluorescence (DF-RF, 298-1017 K). Kinetic complications due to the presence of molecular oxygen in the FP-RF experiments at high temperatures (T > 800 K) were overcome by using NO as the photolytic source of the O atoms. The rate constant, k/sub 1/ (T), derived in this study exhibits extreme non-Arrhenius behavior, but it can be successfully fit to the sum of exponentials expression, 244-1052 K, k/sub 1/(T) = (1.02 +/- 0.06) x 10/sup -11/ exp(-753 +/- 17 K/T) + (2.75 +/- 0.26) x 10/sup -10/ exp(-4220 +/- 550 K/T), in units of cm/sup 3/ molecule/sup -1/ s/sup -1/. Additionally, a fit of the results of this work to a simple transition-state theory expression and the comparison of these results with those of other workers are discussed.

  9. 24 CFR 990.185 - Utilities expense level: Incentives for energy conservation/rate reduction.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... implemented. (ii) The PHA operating subsidy eligibility shall reflect the retention of 100 percent of the... the utility allowances in accordance with provisions in 24 CFR part 965, subpart E. The new allowance... the cost of the improvement (the PHA will be permitted to retain 100 percent of the difference...

  10. 24 CFR 990.185 - Utilities expense level: Incentives for energy conservation/rate reduction.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... implemented. (ii) The PHA operating subsidy eligibility shall reflect the retention of 100 percent of the... the utility allowances in accordance with provisions in 24 CFR part 965, subpart E. The new allowance... the cost of the improvement (the PHA will be permitted to retain 100 percent of the difference...

  11. 24 CFR 990.185 - Utilities expense level: Incentives for energy conservation/rate reduction.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... implemented. (ii) The PHA operating subsidy eligibility shall reflect the retention of 100 percent of the... the utility allowances in accordance with provisions in 24 CFR part 965, subpart E. The new allowance... the cost of the improvement (the PHA will be permitted to retain 100 percent of the difference...

  12. 24 CFR 990.185 - Utilities expense level: Incentives for energy conservation/rate reduction.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... implemented. (ii) The PHA operating subsidy eligibility shall reflect the retention of 100 percent of the... the utility allowances in accordance with provisions in 24 CFR part 965, subpart E. The new allowance... the cost of the improvement (the PHA will be permitted to retain 100 percent of the difference...

  13. The Storekeeper Rating: New Concepts To Improve Training, Assignment, Performance, and Utilization.

    ERIC Educational Resources Information Center

    Sass, Del H.

    Storekeeper personnel skill and knowledge requirements are discussed in terms of training, identification, and utilization. Manual skills which predominate in the material handling functions of supply (storerooms and warehouses) are contrasted to the clerical skills which predominate in the administrative functions (inventory and financial…

  14. Student Ratings of College Courses and College Teachers: Reliability, Generalizability, Validity and Utility.

    ERIC Educational Resources Information Center

    Wood, Peter H.; And Others

    A review of the research literature considers the following questions: (1) what is the general quality of the information resulting from systematic student evaluation of faculty effectiveness?; and (2) what are the consequences of soliciting this information and making it available to those people who may utilize it in their decision making…

  15. In-situ sediment oxygen demand rates in Hammonton Creek, Hammonton, New Jersey, and Crosswicks Creek, near New Egypt, New Jersey, August-October 2009

    USGS Publications Warehouse

    Wilson, Timothy P.

    2014-01-01

    Sediment oxygen demand rates were measured in Hammonton Creek, Hammonton, New Jersey, and Crosswicks Creek, near New Egypt, New Jersey, during August through October 2009. These rates were measured as part of an ongoing water-quality monitoring program being conducted in cooperation with the New Jersey Department of Environmental Protection. Oxygen depletion rates were measured using in-situ test chambers and a non-consumptive optical electrode sensing technique for measuring dissolved oxygen concentrations. Sediment oxygen demand rates were calculated on the basis of these field measured oxygen depletion rates and the temperature of the stream water at each site. Hammonton Creek originates at an impoundment, then flows through pine forest and agricultural fields, and receives discharge from a sewage-treatment plant. The streambed is predominantly sand and fine gravel with isolated pockets of organic-rich detritus. Sediment oxygen demand rates were calculated at four sites on Hammonton Creek and were found to range from -0.3 to -5.1 grams per square meter per day (g/m2/d), adjusted to 20 degrees Celsius. When deployed in pairs, the chambers produced similar values, indicating that the method was working as expected and yielding reproducible results. At one site where the chamber was deployed for more than 12 hours, dissolved oxygen was consumed linearly over the entire test period. Crosswicks Creek originates in a marshy woodland area and then flows through woodlots and pastures. The streambed is predominantly silt and clay with some bedrock exposures. Oxygen depletion rates were measured at three sites within the main channel of the creek, and the calculated sediment oxygen demand rates ranged from -0.33 to -2.5 g/m2/d, adjusted to 20 degrees Celsius. At one of these sites sediment oxygen demand was measured in both a center channel flowing area of a pond in the stream and in a stagnant non-flowing area along the shore of the pond where organic-rich bottom

  16. Martian oxygen escape rate as a function of upstream solar wind density: results from a hybrid model

    NASA Astrophysics Data System (ADS)

    Wang, Xiao-Dong; Holmstroem, Mats

    2015-04-01

    We investigate the dependence of oxygen escape rate at Mars on the proton density of the upstream solar wind using a parallel hybrid model. The model handles ions as particles and electrons as a massless, neutralizing fluid. The model currently contains three ion species: protons and alpha particles from the solar wind, and a heavy ion species from Martian ionosphere, which is atomic oxygen ion in this study. The interplanetary magnetic field is set to follow the typical Parker spiral at Mars with an intensity of 3 nT. The upstream solar wind velocity is 400 km/s, along the -x axis. We vary the upstream proton density from np =0.2 cm-3 to np =25 cm-3 while keeping all other parameters fixed. The oxygen escape rate Q shows a negative correlation with np within the range 0.5 < np < 3.5 cm-3. The ratio between the maximum and the minimum escape rates is ~3. Outside this density range the correlation is positive. This anticorrelation between Q and np within the most probable range of the upstream proton density, and the relative variation of Q are consistent with the latest experimental investigations on the same topic using the ion data from MEX/ASPERA-3 [Ramstad et al., 2014]. We also investigated cases under 500 km/s upstream velocity and CO2+ ions, the results are qualitatively consistent. The modeled magnetospheric morphology reveals two competing escape channels that depend differently on the upstream density. The channel including the pickup ions and the plasma sheet intensifies with increasing upstream density. The channel including the lobe region and the boundary layer intensifies with decreasing upstream density due to a more expanded induced magnetosphere. The latter dominates the ion escape when the density is lower than ~2.5 cm-3. We also investigate the momentum transfer from the shocked solar wind to the induced magnetosphere. References: R. Ramstad, S. Barabash, Y. Futaana, H. Nilsson, M. Holmstroem [2014]: The Martian escape rate as a function of

  17. Appreciating Oxygen

    ERIC Educational Resources Information Center

    Weiss, Hilton M.

    2008-01-01

    Photosynthetic flora and microfauna utilize light from the sun to convert carbon dioxide and water into carbohydrates and oxygen. While these carbohydrates and their derivative hydrocarbons are generally considered to be fuels, it is the thermodynamically energetic oxygen molecule that traps, stores, and provides almost all of the energy that…

  18. Influence of oxygen flow rate on the structural, optical and electrical properties of ZnO films grown by DC magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Gobbiner, Chaya Ravi; Ali Avanee Veedu, Muhammed; Kekuda, Dhananjaya

    2016-04-01

    Zinc oxide thin films were deposited on glass substrates at different oxygen flow rates by DC reactive magnetron sputtering. The oxygen flow rate was found to be one of the crucial parameters which influence structural, optical and electrical properties of grown films. The structural and optical characterization of the deposited films was carried out using X-ray diffraction and UV-visible spectroscopy, respectively. Swanepoel envelope and Drude-Lorentz (DL) models were applied to extract the optoelectronic parameters such as refractive index, dispersion energy and plasma frequency. Structurally, grain size was found to decrease with increase in oxygen flow rate during deposition. Moreover, all the films exhibited preferred (002) orientation confirming c-axis orientation of the films perpendicular to the substrate. For a particular range of oxygen flow rates, columnar growth was achieved. Marginal increase in the optical band gap from 3.14 to 3.22 eV was observed as the oxygen flow rate increased from 3 to 10 sccm. Calculated plasma frequency from the DL model was found to be in the infrared region. It has decreased as oxygen flow rate increased with the value from 1.625 × 1014 rad/s (862 cm-1) to 1.072 × 1014 rad/s (568 cm-1).

  19. Development and implementation of a {open_quotes}green rate{close_quotes} utility wind power project in Michigan

    SciTech Connect

    Smiley, S.B.

    1995-12-31

    Traverse City Light & Power (TCL&P), a Michigan municipal electric utility serving 9,000 customers in the Traverse City, Michigan area is in the final development stages of the first {open_quotes}green rate{close_quotes} wind power project in the USA. By the fall of 1995 the utility will be producing wind generated electricity to supply the annual needs of approximately 200 customers who have voluntarily agreed to pay a green price premium in order to encourage their community electric utility to implement wind power generation. The 500 kW, $620,000 wind power project was promoted in early 1994 with a requirement target of 200 customers - and by mid-year a total of 263 residential and commercial customers had been signed. TCL&P was then obliged to proceed with the project installation as planned and promoted.

  20. Effect of Argon/Oxygen Flow Rate Ratios on DC Magnetron Sputtered Nano Crystalline Zirconium Titanate Thin Films

    NASA Astrophysics Data System (ADS)

    Rani, D. Jhansi; Kumar, A. GuruSampath; Sarmash, T. Sofi; Chandra Babu Naidu, K.; Maddaiah, M.; Rao, T. Subba

    2016-06-01

    High transmitting, non absorbent, nano crystalline zirconium titanate (ZT) thin films suitable for anti reflection coatings (ARC) were deposited on to glass substrates by direct current (DC) magnetron reactive sputtering technique, under distinct Argon to Oxygen (Ar/O2) gas flow rate ratios of 31/1, 30/2, 29/3 and 28/4, with a net gas flow (Ar + O2) of 32sccm, at an optimum substrate temperature of 250°C. The influence of the gas mixture ratio on the film properties has been investigated by employing x-ray diffraction (XRD), ultra violet visible (UV-vis) spectroscopy, atomic force microscopy (AFM), energy dispersive x-ray analysis (EDX) and four point probe methods. The films showed a predominant peak at 30.85° with (111) orientation. The crystallite size reduced from 22.94 nm to 13.5 nm and the surface roughness increased from 11.53 nm to 50.58 nm with increase in oxygen content respectively. The films deposited at 31/1 and 30/2 showed almost similar chemical composition. Increased oxygen content results an increase in electrical resistivity from 3.59 × 103 to 2.1 × 106 Ωm. The film deposited at Ar/O2 of 28/4 exhibited higher average optical transmittance of 91%, but its refractive index is higher than that of what is required for ARC. The films deposited at 31/1 and 30/2 of Ar/O2 possess higher transmittance (low absorbance) apart from suitable refractive index. Thus, these films are preferable candidates for ARC.

  1. Inorganic nitrate supplementation improves muscle oxygenation, O₂ uptake kinetics, and exercise tolerance at high but not low pedal rates.

    PubMed

    Bailey, Stephen J; Varnham, Richard L; DiMenna, Fred J; Breese, Brynmor C; Wylie, Lee J; Jones, Andrew M

    2015-06-01

    We tested the hypothesis that inorganic nitrate (NO3 (-)) supplementation would improve muscle oxygenation, pulmonary oxygen uptake (V̇o2) kinetics, and exercise tolerance (Tlim) to a greater extent when cycling at high compared with low pedal rates. In a randomized, placebo-controlled cross-over study, seven subjects (mean ± SD, age 21 ± 2 yr, body mass 86 ± 10 kg) completed severe-intensity step cycle tests at pedal cadences of 35 rpm and 115 rpm during separate nine-day supplementation periods with NO3 (-)-rich beetroot juice (BR) (providing 8.4 mmol NO3 (-)/day) and placebo (PLA). Compared with PLA, plasma nitrite concentration increased 178% with BR (P < 0.01). There were no significant differences in muscle oxyhemoglobin concentration ([O2Hb]), phase II V̇o2 kinetics, or Tlim between BR and PLA when cycling at 35 rpm (P > 0.05). However, when cycling at 115 rpm, muscle [O2Hb] was higher at baseline and throughout exercise, phase II V̇o2 kinetics was faster (47 ± 16 s vs. 61 ± 25 s; P < 0.05), and Tlim was greater (362 ± 137 s vs. 297 ± 79 s; P < 0.05) with BR compared with PLA. These results suggest that short-term BR supplementation can increase muscle oxygenation, expedite the adjustment of oxidative metabolism, and enhance exercise tolerance when cycling at a high, but not a low, pedal cadence in healthy recreationally active subjects. These findings support recent observations that NO3 (-) supplementation may be particularly effective at improving physiological and functional responses in type II muscle fibers. PMID:25858494

  2. Effect of Argon/Oxygen Flow Rate Ratios on DC Magnetron Sputtered Nano Crystalline Zirconium Titanate Thin Films

    NASA Astrophysics Data System (ADS)

    Rani, D. Jhansi; Kumar, A. GuruSampath; Sarmash, T. Sofi; Chandra Babu Naidu, K.; Maddaiah, M.; Rao, T. Subba

    2016-04-01

    High transmitting, non absorbent, nano crystalline zirconium titanate (ZT) thin films suitable for anti reflection coatings (ARC) were deposited on to glass substrates by direct current (DC) magnetron reactive sputtering technique, under distinct Argon to Oxygen (Ar/O2) gas flow rate ratios of 31/1, 30/2, 29/3 and 28/4, with a net gas flow (Ar + O2) of 32sccm, at an optimum substrate temperature of 250°C. The influence of the gas mixture ratio on the film properties has been investigated by employing x-ray diffraction (XRD), ultra violet visible (UV-vis) spectroscopy, atomic force microscopy (AFM), energy dispersive x-ray analysis (EDX) and four point probe methods. The films showed a predominant peak at 30.85° with (111) orientation. The crystallite size reduced from 22.94 nm to 13.5 nm and the surface roughness increased from 11.53 nm to 50.58 nm with increase in oxygen content respectively. The films deposited at 31/1 and 30/2 showed almost similar chemical composition. Increased oxygen content results an increase in electrical resistivity from 3.59 × 103 to 2.1 × 106 Ωm. The film deposited at Ar/O2 of 28/4 exhibited higher average optical transmittance of 91%, but its refractive index is higher than that of what is required for ARC. The films deposited at 31/1 and 30/2 of Ar/O2 possess higher transmittance (low absorbance) apart from suitable refractive index. Thus, these films are preferable candidates for ARC.

  3. Factors controlling the growth rate, carbon and oxygen isotope variation in modern calcite precipitation in a subtropical cave, Southwest China

    NASA Astrophysics Data System (ADS)

    Pu, Junbing; Wang, Aoyu; Shen, Licheng; Yin, Jianjun; Yuan, Daoxian; Zhao, Heping

    2016-04-01

    A prerequisite for using cave speleothems to reconstruct palaeoenvironmental conditions is an accurate understanding of specific factors controlling calcite growth, in particular the isotopic partitioning of oxygen (δ18O) and carbon (δ13C) which are the most commonly used proxies. An in situ monitoring study from April 2008 to September 2009 at Xueyu Cave, Chongqing, SW China, provides insight into the controls on calcite growth rates, drip water composition, cave air parameters and δ18O and δ13C isotopic values of modern calcite precipitation. Both cave air PCO2 and drip water hydrochemical characteristics show obvious seasonality driven by seasonal changes in the external environment. Calcite growth rates also display clear intra-annual variation, with the lowest values occurring during wet season and peak values during the dry season. Seasonal variations of calcite growth rate are primarily controlled by variations of cave air PCO2 and drip water rate. Seasonal δ18O-VPDB and δ13C-VPDB in modern calcite precipitates vary, with more negative values in the wet season than in the dry season. Strong positive correlation of δ18O-VPDB vs. δ13C-VPDB is due to simultaneous enrichment of both isotopes in the calcite. This correlation indicates that kinetic fractionation occurs between parent drip water and depositing calcite, likely caused by the variations of cave air PCO2 and drip rate influenced by seasonal cave ventilation. Kinetic fractionation amplifies the equilibrium fractionation value of calcite δ18O (by ∼1.5‰) and δ13C (by ∼1.7‰), which quantitatively reflects surface conditions during the cave ventilation season. These results indicate that the cave monitoring of growth rate and δ18O and δ13C of modern calcite precipitation are necessary in order to use a speleothem to reconstruct palaeoenvironment.

  4. Performance of Regolith Feed Systems for Analog Field Tests of In-Situ Resource Utilization Oxygen Production Plants in Mauna Kea, Hawaii

    NASA Technical Reports Server (NTRS)

    Townsend, Ivan I.; Mueller, Robert P.; Mantovani, James G.; Zacny, Kris A.; Craft, Jack

    2010-01-01

    This paper focuses on practical aspects of mechanical auger and pneumatic regolith conveying system feeding In-Situ Resource Utilization Oxygen production plants. The subsystems of these feedstock delivery systems include an enclosed auger device, pneumatic venturi educator, jet-lift regolith transfer, innovative electro-cyclone gas-particle separation/filtration systems, and compressors capable of dealing with hot hydrogen and/or methane gas re-circulating in the system. Lessons learned from terrestrial laboratory, reduced gravity and field testing on Mauna Kea Volcano in Hawaii during NASA lunar analog field tests will be discussed and practical design tips will be presented.

  5. A comparison of measured radionuclide release rates from Three Mile Island Unit-2 core debris for different oxygen chemical potentials

    SciTech Connect

    Baston, V.F.; Hofstetter, K.J.; Ryan, R.F.

    1987-03-01

    Chemical and radiochemical analyses of reactor coolant samples taken during defueling of the Three Mile Island Unit-2 (TMI-2) reactor provide relevant data to assist in understanding the solution chemistry of the radionuclides retained within the TMI-2 reactor coolant system. Hydrogen peroxide was added to various plant systems to provide disinfection for microbial contamination and has provided the opportunity to observe radionuclide release under different oxygen chemical potentials. A comparison of the radionuclide release rates with and without hydrogen peroxide has been made for these separate but related cases, i.e., the fuel transfer canal and connecting spent-fuel pool A with the TMI-2 reactor plenum in the fuel transfer canal, core debris grab sample laboratory experiments, and the reactor vessel fluid and associated core debris. Correlation and comparison of these data indicate a physical parameter dependence (surface-to-volume ratio) affecting all radionuclide release; however, selected radionuclides also demonstrate a chemical dependence release under the different oxygen chemical potentials. Chemical and radiochemical analyses of reactor coolant samples taken during defueling of the Three Mile Island Unit-2 (TMI-2) reactor provide relevant data to assist in understanding the solution chemistry of the radionuclides retained within the TMI-2 reactor coolant system.

  6. A Novel Layered Sedimentary Rocks Structure of the Oxygen-Enriched Carbon for Ultrahigh-Rate-Performance Supercapacitors.

    PubMed

    Zhang, Lin-Lin; Li, Huan-Huan; Shi, Yan-Hong; Fan, Chao-Ying; Wu, Xing-Long; Wang, Hai-Feng; Sun, Hai-Zhu; Zhang, Jing-Ping

    2016-02-17

    In this paper, gelatin as a natural biomass was selected to successfully prepare an oxygen-enriched carbon with layered sedimentary rocks structure, which exhibited ultrahigh-rate performance and excellent cycling stability as supercapacitors. The specific capacitance reached 272.6 F g(-1) at 1 A g(-1) and still retained 197.0 F g(-1) even at 100 A g(-1) (with high capacitance retention of 72.3%). The outstanding electrochemical performance resulted from the special layered structure with large surface area (827.8 m(2) g(-1)) and high content of oxygen (16.215 wt %), which effectively realized the synergistic effects of the electrical double-layer capacitance and pseudocapacitance. Moreover, it delivered an energy density of 25.3 Wh kg(-1) even with a high power density of 34.7 kW kg(-1) and ultralong cycling stability (with no capacitance decay even over 10,000 cycles at 2 A g(-1)) in a symmetric supercapacitor, which are highly desirable for their practical application in energy storage devices and conversion. PMID:26815316

  7. Quantification of Low-Level Drug Effects Using Real-Time, in vitro Measurement of Oxygen Consumption Rate.

    PubMed

    Neal, Adam; Rountree, Austin M; Philips, Craig W; Kavanagh, Terrance J; Williams, Dominic P; Newham, Peter; Khalil, Gamal; Cook, Daniel L; Sweet, Ian R

    2015-12-01

    There is a general need to detect toxic effects of drugs during preclinical screening. We propose that increased sensitivity of xenobiotics toxicity combined with improved in vitro physiological recapitulation will more accurately assess potentially toxic perturbations of cellular biochemistry that are near in vivo pharmacological exposure levels. Importantly, measurement of such cytopathologies avoids activating mechanisms mediating toxicity at suprapharmacologic levels not relevant to in vivo effects. We present a sensitive method to measure changes in oxygen consumption rate (OCR), a well-established parameter reflecting a potential hazard, in response to exposure to pharmacologic levels of drugs using a flow culture system and state of the art oxygen sensing system. We tested metformin and acetaminophen on rat liver slices to illustrate the method. The features of the method include continuous and very stable measurement of OCR over the course of 48 h in liver slices in a continuous flow chamber with the ability to resolve changes as small as 0.3%/h. Kinetic modeling of metformin inhibition of OCR over a wide range of concentrations revealed both a slow and fast mechanism, where the fast mechanism activated only at concentrations above 0.6 mM. For both drugs, small amounts of inhibition were reversible, but higher decrements were irreversible. Overall the study highlights the advantages of measuring low-level toxicity so as to avoid the common extrapolations made about drug toxicity based on effects of drugs tested at suprapharmacologic levels. PMID:26396153

  8. Oxygen Partial Pressure Is a Rate-Limiting Parameter for Cell Proliferation in 3D Spheroids Grown in Physioxic Culture Condition

    PubMed Central

    Gomes, Aurélie; Guillaume, Ludivine; Grimes, David Robert; Fehrenbach, Jérôme; Lobjois, Valérie; Ducommun, Bernard

    2016-01-01

    The in situ oxygen partial pressure in normal and tumor tissues is in the range of a few percent. Therefore, when studying cell growth in 3D culture systems, it is essential to consider how the physiological oxygen concentration, rather than the one in the ambient air, influences the proliferation parameters. Here, we investigated the effect of reducing oxygen partial pressure from 21% to 5% on cell proliferation rate and regionalization in a 3D tumor spheroid model. We found that 5% oxygen concentration strongly inhibited spheroid growth, changed the proliferation gradient and reduced the 50% In Depth Proliferation index (IDP50), compared with culture at 21% oxygen. We then modeled the oxygen partial pressure profiles using the experimental data generated by culturing spheroids in physioxic and normoxic conditions. Although hypoxia occurred at similar depth in spheroids grown in the two conditions, oxygen partial pressure was a major rate-limiting factor with a critical effect on cell proliferation rate and regionalization only in spheroids grown in physioxic condition and not in spheroids grown at atmospheric normoxia. Our findings strengthen the need to consider conducting experiment in physioxic conditions (i.e., tissue normoxia) for proper understanding of cancer cell biology and the evaluation of anticancer drugs in 3D culture systems. PMID:27575790

  9. Oxygen Partial Pressure Is a Rate-Limiting Parameter for Cell Proliferation in 3D Spheroids Grown in Physioxic Culture Condition.

    PubMed

    Gomes, Aurélie; Guillaume, Ludivine; Grimes, David Robert; Fehrenbach, Jérôme; Lobjois, Valérie; Ducommun, Bernard

    2016-01-01

    The in situ oxygen partial pressure in normal and tumor tissues is in the range of a few percent. Therefore, when studying cell growth in 3D culture systems, it is essential to consider how the physiological oxygen concentration, rather than the one in the ambient air, influences the proliferation parameters. Here, we investigated the effect of reducing oxygen partial pressure from 21% to 5% on cell proliferation rate and regionalization in a 3D tumor spheroid model. We found that 5% oxygen concentration strongly inhibited spheroid growth, changed the proliferation gradient and reduced the 50% In Depth Proliferation index (IDP50), compared with culture at 21% oxygen. We then modeled the oxygen partial pressure profiles using the experimental data generated by culturing spheroids in physioxic and normoxic conditions. Although hypoxia occurred at similar depth in spheroids grown in the two conditions, oxygen partial pressure was a major rate-limiting factor with a critical effect on cell proliferation rate and regionalization only in spheroids grown in physioxic condition and not in spheroids grown at atmospheric normoxia. Our findings strengthen the need to consider conducting experiment in physioxic conditions (i.e., tissue normoxia) for proper understanding of cancer cell biology and the evaluation of anticancer drugs in 3D culture systems. PMID:27575790

  10. Effect of oxygen transfer rate on the composition of the pectolytic enzyme complex of Aspergillus niger

    SciTech Connect

    Zetelaki-Horvath, K.; Vas, K.

    1981-01-01

    Optimal agitation and aeration conditions (assuring O/sub 2/ transfer rates (OTR) of 12-179 mmol/L-h) were determined for pectin lyase (PL) synthesis of an Aspergillus niger strain. Components of the pectolytic enzyme complex were also investigated in order to determine whether their O/sub 2/ demand is identical with or different from that of pectin lyase. Should the latter be the case, a possibility would be given to produce enzyme complexes of different agitation and aeration conditions. The mycelium yield of Aspergillus niger was maximum at an OTR of 100 mmol/L-h. The yields of the various pectolytic enzymes reached maximum at different OTRs. PL production was highest (0.555 mumol/min-mL) at an OTR of 60 mmol/L-h. Endopolygalacturonase (PG) production has a maximum at OTR 49 mmol/L-h, with a 2nd peak at 100-135 mmol O2/L-h. Pectin esterase (PE) synthesis showed a maximum at an OTR of 12-14 mmol/L-h, while both apple juice clarifying and macerating activities gave 2 maximum at 14 and 60 mmol/L-h due to the optima of PE and endo-PG. Macerating activity showed a high value at OTR optimal for PL production as well.

  11. Predicting SF-6D utility scores from the Neck Disability Index and Numeric Rating Scales for Neck and Arm Pain

    PubMed Central

    Carreon, Leah Y.; Anderson, Paul A.; McDonough, Christine M.; Djurasovic, Mladen; Glassman, Steven D.

    2010-01-01

    Study Design Cross-sectional cohort Objective This study aims to provide an algorithm estimate SF-6D utilities using data from the NDI, neck pain and arm pain scores. Summary of Background Data Although cost-utility analysis is increasingly used to provide information about the relative value of alternative interventions, health state values or utilities are rarely available from clinical trial data. The Neck Disability Index (NDI) and numeric rating scales for neck and arm pain, are widely used disease-specific measures of symptoms, function and disability in patients with cervical degenerative disorders. The purpose of this study is to provide an algorithm to allow estimation of SF-6D utilities using data from the NDI, and numeric rating scales for neck and arm pain. Methods SF-36, NDI, neck and arm pain rating scale scores were prospectively collected pre-operatively, at 12 and 24 months post-operatively in 2080 patients undergoing cervical fusion for degenerative disorders. SF-6D utilities were computed and Spearman correlation coefficients were calculated for paired observations from multiple time points between NDI, neck and arm pain scores and SF-6D utility scores. SF-6D scores were estimated from the NDI, neck and arm pain scores using a linear regression model. Using a separate, independent dataset of 396 patients in which and NDI scores were available SF-6D was estimated for each subject and compared to their actual SF-6D. Results The mean age for those in the development sample, was 50.4 ± 11.0 years and 33% were male. In the validation sample the mean age was 53.1 ± 9.9 years and 35% were male. Correlations between the SF-6D and the NDI, neck and arm pain scores were statistically significant (p<0.0001) with correlation coefficients of 0.82, 0.62, and 0.50 respectively. The regression equation using NDI alone to predict SF-6D had an R2 of 0.66 and a root mean square error (RMSE) of 0.056. In the validation analysis, there was no statistically

  12. Unconventional Gas and Oil Drilling Is Associated with Increased Hospital Utilization Rates.

    PubMed

    Jemielita, Thomas; Gerton, George L; Neidell, Matthew; Chillrud, Steven; Yan, Beizhan; Stute, Martin; Howarth, Marilyn; Saberi, Pouné; Fausti, Nicholas; Penning, Trevor M; Roy, Jason; Propert, Kathleen J; Panettieri, Reynold A

    2015-01-01

    Over the past ten years, unconventional gas and oil drilling (UGOD) has markedly expanded in the United States. Despite substantial increases in well drilling, the health consequences of UGOD toxicant exposure remain unclear. This study examines an association between wells and healthcare use by zip code from 2007 to 2011 in Pennsylvania. Inpatient discharge databases from the Pennsylvania Healthcare Cost Containment Council were correlated with active wells by zip code in three counties in Pennsylvania. For overall inpatient prevalence rates and 25 specific medical categories, the association of inpatient prevalence rates with number of wells per zip code and, separately, with wells per km2 (separated into quantiles and defined as well density) were estimated using fixed-effects Poisson models. To account for multiple comparisons, a Bonferroni correction with associations of p<0.00096 was considered statistically significant. Cardiology inpatient prevalence rates were significantly associated with number of wells per zip code (p<0.00096) and wells per km2 (p<0.00096) while neurology inpatient prevalence rates were significantly associated with wells per km2 (p<0.00096). Furthermore, evidence also supported an association between well density and inpatient prevalence rates for the medical categories of dermatology, neurology, oncology, and urology. These data suggest that UGOD wells, which dramatically increased in the past decade, were associated with increased inpatient prevalence rates within specific medical categories in Pennsylvania. Further studies are necessary to address healthcare costs of UGOD and determine whether specific toxicants or combinations are associated with organ-specific responses. PMID:26176544

  13. Unconventional Gas and Oil Drilling Is Associated with Increased Hospital Utilization Rates

    PubMed Central

    Neidell, Matthew; Chillrud, Steven; Yan, Beizhan; Stute, Martin; Howarth, Marilyn; Saberi, Pouné; Fausti, Nicholas; Penning, Trevor M.; Roy, Jason; Propert, Kathleen J.; Panettieri, Reynold A.

    2015-01-01

    Over the past ten years, unconventional gas and oil drilling (UGOD) has markedly expanded in the United States. Despite substantial increases in well drilling, the health consequences of UGOD toxicant exposure remain unclear. This study examines an association between wells and healthcare use by zip code from 2007 to 2011 in Pennsylvania. Inpatient discharge databases from the Pennsylvania Healthcare Cost Containment Council were correlated with active wells by zip code in three counties in Pennsylvania. For overall inpatient prevalence rates and 25 specific medical categories, the association of inpatient prevalence rates with number of wells per zip code and, separately, with wells per km2 (separated into quantiles and defined as well density) were estimated using fixed-effects Poisson models. To account for multiple comparisons, a Bonferroni correction with associations of p<0.00096 was considered statistically significant. Cardiology inpatient prevalence rates were significantly associated with number of wells per zip code (p<0.00096) and wells per km2 (p<0.00096) while neurology inpatient prevalence rates were significantly associated with wells per km2 (p<0.00096). Furthermore, evidence also supported an association between well density and inpatient prevalence rates for the medical categories of dermatology, neurology, oncology, and urology. These data suggest that UGOD wells, which dramatically increased in the past decade, were associated with increased inpatient prevalence rates within specific medical categories in Pennsylvania. Further studies are necessary to address healthcare costs of UGOD and determine whether specific toxicants or combinations are associated with organ-specific responses. PMID:26176544

  14. Cooling rates of living and killed chicken and quail eggs in air and in helium-oxygen gas mixture.

    PubMed

    Tazawa, H; Turner, J S; Paganelli, C V

    1988-01-01

    1. In a helium atmosphere, heat is dissipated from a surface 3.5 times faster than it is in air. Eggs in a helium-oxygen atmosphere cool only 1.4 times faster than they cool in air. This signifies that internal resistance to heat flow is a significant factor in the cooling rates of eggs. 2. Heat flow occurs inside an egg in two ways: by conduction through the tissues and in flowing blood. Killing an embryo stops the latter, but not the former. Eggs cool more slowly after they have been killed, signifying that blood flow can be an important component in an egg's internal flows of heat. 3. Blood flow should be a relatively more important component of heat flow in large eggs than in small eggs. The difference in conductance between living and killed eggs is larger in 60 g chicken eggs than it is in 10 g quail eggs. PMID:2900113

  15. The effects of perceiving color in living environment on QEEG, oxygen saturation, pulse rate, and emotion regulation in humans.

    PubMed

    Sroykham, Watchara; Wongsathikun, J; Wongsawat, Y

    2014-01-01

    Light and color have been shown to have substantial physical, psychological and sociological effects on humans. Hence, an investigation on the effect of changes in light and color to the biological signals is a challenging problem. Five participants were measured the oxygen saturation (SpO2), pulse rate, and quantitative electroencephalogram (QEEG) in six colors (white, blue, green, yellow, red and black) of living environment for 5 minutes per color. Then all participants were asked to answer the emotional questionnaire of BRUMS and color performance for each color environment. The results showed brain activity of high beta wave (25-30 Hz) that associated with alertness, agitation, mental activity, and general activation of mind and body functions (at frontal lobes and temporal lobes) in red and yellow colored rooms were higher than blue, green, white and black colored rooms, respectively. It also had the relationship with the psychological effect (BRUMS). The amplitude asymmetry of beta wave (12-25 Hz) was highly attenuated in warm color (red and yellow colored rooms), moderately attenuated in cool color (green and blue colored room) and little attenuated in white and black colored rooms. The BRUMS showed that red and yellow yielded significant effect on anger (F = 4.966, p = 0.002) and confusion (F=3.853, p=0.008). Red and green color yielded high effect on vigor. Green color did not affect the depression. Blue color yielded moderate effect on confusion, tension and fatigue. White and black colors yielded low effect on any mood, but black color had no effect on vigor. In addition, we cannot observe any significant changes of pulse rate and blood oxygen saturation in each color. The results can possibly be used as the recommendation to design the room for either normal people or patients. PMID:25571419

  16. Are the oxygen uptake and heart rate off-kinetics influenced by the intensity of prior exercise?

    PubMed

    do Nascimento Salvador, Paulo Cesar; de Aguiar, Rafael Alves; Teixeira, Anderson Santiago; Souza, Kristopher Mendes de; de Lucas, Ricardo Dantas; Denadai, Benedito Sérgio; Guglielmo, Luiz Guilherme Antonacci

    2016-08-01

    The aim of this study was to investigate the effect of prior exercise on the heart rate (HR) and oxygen uptake (VO2) off-kinetics after a subsequent high-intensity running exercise. Thirteen male futsal players (age 22.8±6.1years) performed a series of high-intensity bouts without prior exercise (control), preceded by a prior same intensity continuous exercise (CE+CE) and a prior sprint exercise (SE+CE). The magnitude of excess post-exercise oxygen consumption (EPOCm-4.25±0.19 vs. 3.69±0.20Lmin(-1) in CE+CE and 3.62±0.18Lmin(-1) in control; p<0.05) and the parasympathetic reactivation (HRR60s-33±3 vs. 37±3bpm in CE+CE and 42±3 bpm in control; p<0.05) in the SE+CE were higher and slower, compared with another two conditions. The EPOCτ (time to attain 63% of total response; 53±2s) and the heart rate time-course (HRτ-86±5s) were significantly longer after the SE+CE condition than control transition (48±2s and 69±5s, respectively; p<0.05). The SE+CE induce greater stress on the metabolic function, respiratory system and autonomic nervous system regulation during post-exercise recovery than CE, highlighting that the inclusion of sprint-based exercises can be an effective strategy to increase the total energy expenditure following an exercise session. PMID:27181327

  17. In vitro measurements of oxygen consumption rates in hTERT-RPE cells exposed to low levels of red light

    NASA Astrophysics Data System (ADS)

    Wigle, Jeffrey C.; Castellanos, Cherry C.

    2016-03-01

    Exposure to 2.88 J/cm2 of red light induces an adaptive response against a lethal pulse of 2.0 μm laser radiation in hTERT-RPE cells in vitro, but not in a knockdown mutant for vascular endothelial growth factor c (VEGF-C). The generally accepted initiation sequence for photobiomodulation is that absorption of red light by cytochome c oxidase (CCOX) of the electron transport chain increases the binding affinity of CCOX for O2 vs. nitric oxide (NO). This results in displacement of NO by O2 in the active site of CCOX, thereby increasing cellular respiration and intracellular ATP. We've previously reported that red-light exposure induces a small, but consistently reproducible, increase in NO levels in these cells. But the relative importance of NO and oxidative phosphorylation is unclear because little is known about the relative contributions of NO and ATP to the response. However, if NO dissociation from CCOX actually increases oxidative phosphorylation, one should see a corresponding increase in oxygen consumption. A Seahorse Extracellular Flux Analyzer was used to measure oxygen consumption rates (OCR) in normal and mutant cells as a proxy for oxidative phosphorylation. Both basal respiration and maximum respiration rates in normal cells are significantly higher than in the mutant. The normal cells have a significant amount of "excess capacity," whereas the VEGF-C(KD) have little or none. The OCR in exposed normal cells is lower than in unexposed cells when measured immediately after exposure. The exposures used for these experiments had no effect on the OCR in mutant cells.

  18. Prekindergarten Children's Executive Functioning Skills and Achievement Gains: The Utility of Direct Assessments and Teacher Ratings

    ERIC Educational Resources Information Center

    Fuhs, Mary Wagner; Farran, Dale Clark; Nesbitt, Kimberly Turner

    2015-01-01

    An accumulating body of evidence suggests that young children who exhibit greater executive functioning (EF) skills in early childhood also achieve more academically. The goal of the present study was to examine the unique contributions of direct assessments and teacher ratings of children's EF skills at the beginning of prekindergarten (pre-k) to…

  19. Solar Energy Systems for Lunar Oxygen Generation

    NASA Technical Reports Server (NTRS)

    Colozza, Anthony J.; Heller, Richard S.; Wong, Wayne A.; Hepp, Aloysius F.

    2010-01-01

    An evaluation of several solar concentrator-based systems for producing oxygen from lunar regolith was performed. The systems utilize a solar concentrator mirror to provide thermal energy for the oxygen production process. Thermal energy to power a Stirling heat engine and photovoltaics are compared for the production of electricity. The electricity produced is utilized to operate the equipment needed in the oxygen production process. The initial oxygen production method utilized in the analysis is hydrogen reduction of ilmenite. Utilizing this method of oxygen production a baseline system design was produced. This baseline system had an oxygen production rate of 0.6 kg/hr with a concentrator mirror size of 5 m. Variations were performed on the baseline design to show how changes in the system size and process (rate) affected the oxygen production rate. An evaluation of the power requirements for a carbothermal lunar regolith reduction reactor has also been conducted. The reactor had a total power requirement between 8,320 to 9,961 W when producing 1000 kg/year of oxygen. The solar concentrator used to provide the thermal power (over 82 percent of the total energy requirement) would have a diameter of less than 4 m.

  20. The utilization rate of antenatal care after health sector reform implementation in rural areas of Islamic Republic of Iran

    PubMed Central

    Alikhasi, Narges; Khadivi, Reza; Kheyri, Maryam

    2014-01-01

    Background: Improving the utilization rate of antenatal care is a critical strategy for achieving the reproductive health goals in Iran. The aim of this study was to assess the utilization rate of antenatal care (ANC) by women after health sector reform (HSR) interventions in rural areas of Islamic Republic of Iran (IR Iran). Materials and Methods: This is a retrospective cross-sectional study. The data were gathered by cluster sampling from 400 motherhood records of mothers whose last pregnancies had been terminated in the first 3 months of 2013. Data were collected from 21 rural health centers of Isfahan district during the year 2013. The utilization rate of ANC by mothers was assessed by the number of visits they had, the time of the first ANC visit, the occurrence of pregnancy- or delivery-related complications, and the number of postpartum visits. Results: The mean time of the first ANC was 9 ± 5.23th week of gestational age. For 69.3% of pregnant women, the first ANC was before the 12th week. Overall, the frequency of ANC visits ranged from 2 to 21, with the average of 10.6 ± 3.23 visits. 93.8% of the utilized ANC visits were adequate. 99.8% of the deliveries took place in the hospital. 99% of mothers had at least one visit in the postpartum period. 4% of the mothers had suffered from pregnancy-related complications. Conclusion: It seems that IR Iran has achieved to one of the important objectives by its reform in health care access, that is, more ANC for pregnant women. PMID:25558259

  1. Estimation of the rate of oxygen consumption of the common eider duck (Somateria mollissima), with some measurements of heart rate during voluntary dives.

    PubMed

    Hawkins, P A; Butler, P J; Woakes, A J; Speakman, J R

    2000-09-01

    The relationship between heart rate (f(H)) and rate of oxygen consumption (V(O2)) was established for a marine diving bird, the common eider duck (Somateria mollissima), during steady-state swimming and running exercise. Both variables increased exponentially with speed during swimming and in a linear fashion during running. Eleven linear regressions of V(O2) (ml kg(-1 )min(-1)) on f(H) (beats min(-1)) were obtained: five by swimming and six by running the birds. The common regression was described by V(O2)=10.1 + 0.15f(H) (r(2)=0.46, N=272, P<0.0001). The accuracy of this relationship for predicting mean V(O2) was determined for a group of six birds by recording f(H) continuously over a 2-day period and comparing estimated V(O2) obtained using the common regression with (i) V(O2) estimated using the doubly labelled water technique (DLW) and (ii) V(O2) measured using respirometry. A two-pool model produced the most accurate estimated V(O2) using DLW. Because of individual variability within mean values of V(O2) estimated using both techniques, there was no significant difference between mean V(O2) estimated using f(H) or DLW and measured V(O2) values (P>0.2), although individual errors were substantially less when f(H) was used rather than DLW to estimate V(O2). Both techniques are, however, only suitable for estimating mean V(O2) for a group of animals, not for individuals. Heart rate and behaviour were monitored during a bout of 63 voluntary dives by one female bird in an indoor tank 1.7 m deep. Tachycardia occurred both in anticipation of and following each dive. Heart rate decreased before submersion but was above resting values for the whole of the dive cycle. Mean f(H) at mean dive duration was significantly greater than f(H) while swimming at maximum sustainable surface speeds. Heart rate was used to estimate mean V(O2) during the dive cycle and to predict aerobic dive limit (ADL) for shallow dives. PMID:10952881

  2. Microbial sulfate reduction rates and sulfur and oxygen isotope fractionations at oil and gas seeps in deepwater Gulf of Mexico

    SciTech Connect

    Aharon, P.; Fu, B.

    2000-01-01

    sulfate reduction and anaerobic methane oxidation are the dominant microbial processes occurring in hydrate-bearing sediments at bathyal depths in the Gulf of Mexico where crude oil and methane are advecting through fault conduits to the seafloor. The oil and gas seeps are typically overlain by chemosynthetic communities consisting of thiotrophic bacterial mats (Beggiatoa spp.) and methanotrophic mussels (Bathymodiolus spp.), respectively. Cores were recovered with a manned submersible from fine-grained sediments containing dispersed gas hydrates at the threshold of stability. Estimated sulfate reduction rates are variable but generally are substantially higher in crude oil seeps (up to 50 times) and methane seeps (up to 600 times) relative to a non-seep reference sediment. Sulfur and oxygen isotope fractionation factors are highest in the reference sediment but substantially lower in the seep sediments and are controlled primarily by kinetic factors related to sulfate reduction rates. Kinetic effects also control the {delta}{sup 34}S/{delta}{sup 18}O ratios such that slow microbial rates yield low ratios whereas faster rates yield progressively higher ratios. The seep data contradict previous claims that {delta}{sup 34}S/{delta}{sup 18}O ratios are diagnostic of either microbial sulfate reduction at a fixed {delta}{sup 34}S/{delta}{sup 18}O ratio of 4/1 or lower ratios caused by SO{sub 4}-H{sub 2}O equilibration at ambient temperatures. The new results offer a better understanding of methane removal via anaerobic oxidation in the sulfate reduction zone of hydrate-bearing sediments and have significant implications regarding the origin and geochemical history of sedimentary sulfate reconstructed on the basis of {delta}{sup 34}S and {delta}{sup 18}O compositions.

  3. Can we improve the clinical utility of respiratory rate as a monitored vital sign?

    PubMed

    Chen, Liangyou; Reisner, Andrew T; Gribok, Andrei; McKenna, Thomas M; Reifman, Jaques

    2009-06-01

    Respiratory rate (RR) is a basic vital sign, measured and monitored throughout a wide spectrum of health care settings, although RR is historically difficult to measure in a reliable fashion. We explore an automated method that computes RR only during intervals of clean, regular, and consistent respiration and investigate its diagnostic use in a retrospective analysis of prehospital trauma casualties. At least 5 s of basic vital signs, including heart rate, RR, and systolic, diastolic, and mean arterial blood pressures, were continuously collected from 326 spontaneously breathing trauma casualties during helicopter transport to a level I trauma center. "Reliable" RR data were identified retrospectively using automated algorithms. The diagnostic performances of reliable versus standard RR were evaluated by calculation of the receiver operating characteristic curves using the maximum-likelihood method and comparison of the summary areas under the receiver operating characteristic curves (AUCs). Respiratory rate shows significant data-reliability differences. For identifying prehospital casualties who subsequently receive a respiratory intervention (hospital intubation or tube thoracotomy), standard RR yields an AUC of 0.59 (95% confidence interval, 0.48-0.69), whereas reliable RR yields an AUC of 0.67 (0.57-0.77), P < 0.05. For identifying casualties subsequently diagnosed with a major hemorrhagic injury and requiring blood transfusion, standard RR yields an AUC of 0.60 (0.49-0.70), whereas reliable RR yields 0.77 (0.67-0.85), P < 0.001. Reliable RR, as determined by an automated algorithm, is a useful parameter for the diagnosis of respiratory pathology and major hemorrhage in a trauma population. It may be a useful input to a wide variety of clinical scores and automated decision-support algorithms. PMID:19008777

  4. Utility of late summer transient snowline migration rate on Taku Glacier, Alaska

    NASA Astrophysics Data System (ADS)

    Pelto, M.

    2011-12-01

    On Taku Glacier, Alaska a combination of field observations of snow water equivalent (SWE) from snowpits and probing in the vicinity of the transient snowline (TSL) are used to quantify the mass balance gradient. The balance gradient derived from the TSL and SWE measured in snowpits at 1000 m from 1998-2010 ranges from 2.6-3.8 mm m-1. Probing transects from 950 m-1100 m directly measure SWE and yield a slightly higher balance gradient of 3.3-3.8 mm m-1. The TSL on Taku Glacier is identified in MODIS and Landsat 4 and 7 Thematic Mapper images for 31 dates during the 2004-2010 period to assess the consistency of its rate of rise and reliability in assessing ablation for mass balance assessment. For example, in 2010, the TSL was 750 m on 28 July, 800 m on 5 August, 875 m on 14 August, 925 m on 30 August, and 975 m on 20 September. The mean observed probing balance gradient was 3.3 mm m-1, combined with the TSL rise of 3.7 m day-1 yields an ablation rate of 12.2 mm day-1 from mid-July to mid-Sept, 2010. The TSL rise in the region from 750-1100 m on Taku Glacier during eleven periods each covering more than 14 days during the ablation season indicates a mean TSL rise of 3.7 m day-1, the rate of rise is relatively consistent ranging from 3.1 to 4.4 m day-1. This rate is useful for ascertaining the final ELA if images or observations are not available near the end of the ablation season. The mean ablation from 750-1100 m during the July-September period determined from the TSL rise and the observed balance gradient is 11-13 mm day-1 on Taku Glacier during the 2004-2010 period. The potential for providing an estimate of bn from TSL observations late in the melt season from satellite images combined with the frequent availability of such images provides a means for efficient mass balance assessment in many years and on many glaciers.

  5. Metabolic rate measurement system

    NASA Technical Reports Server (NTRS)

    Koester, K.; Crosier, W.

    1980-01-01

    The Metabolic Rate Measurement System (MRMS) is an uncomplicated and accurate apparatus for measuring oxygen consumption and carbon dioxide production of a test subject. From this one can determine the subject's metabolic rate for a variety of conditions, such as resting or light exercise. MRMS utilizes an LSI/11-03 microcomputer to monitor and control the experimental apparatus.

  6. Oxygen uptake, heart rate and blood lactate concentration during a normal training session of an aerobic dance class.

    PubMed

    De Angelis, M; Vinciguerra, G; Gasbarri, A; Pacitti, C

    1998-07-01

    The aim of this research was to investigate the physiological responses and, in particular, the participation of lactic acid anaerobic metabolism in aerobic dance, which is claimed to be pure aerobic exercise. In contrast to previous studies, that have put subjects in very unfamiliar situations, the parameters were monitored in the familiar context of gymnasium, practice routine and habitual instructor. A group of 30 skilled fairly well-trained women performed their usual routine, a combination of the two styles: low (LI) and high impact (HI), and were continuously monitored for heart rate (HR) and every 8 min for blood lactate concentration ([La-]b). Of the group, 15 were tested to determine their maximal aerobic power (VO2max) using a cycle-ergometer. They were also monitored during the routine for oxygen uptake (VO2) by a light telemetric apparatus. The oxygen pulses of the routine and of the corresponding exercise intensity in the incremental test were not statistically different. The mean values in the exercise session were: peak HR 92.8 (SD 7.8)% of the subject's maximal theoretical value, peak VO2 99.5 (SD 12.4)% of VO2max, maximal [La-]b 6.1 (SD 1.7) mmol x l(-1), and mean 4.8 (SD 1.3) mmol x l(-1). Repeated measures ANOVA found statistically significant differences between the increasing [La-]b values (P < 0.001). In particular, the difference between the [La-]b values at the end of the mainly LI phase and those of the LI-HI combination phase, and the difference between the samples during the combination LI-HI phase were both statistically significant (both P = 0.002 and P = 0.002). The similar oxygen pulses confirmed the validity of the present experiment design and the reliability of HR monitoring in this activity. The HR, VO2 and, above all, the increase of [La-]b to quite high values, showing a non steady state, demonstrated the high metabolic demand made by this activity that involved lactic acid metabolism at a much higher level than expected. PMID

  7. Results from the Southeast Oahu, Hawaii, Shoreline Erosion Study Utilizing the PX and PXT Shoreline Erosion Rate Methods

    NASA Astrophysics Data System (ADS)

    Romine, B. M.; Genz, A.; Fletcher, C. H.; Frazer, L. N.; Barbee, M. M.; Lim, S.; Dyer, M.

    2007-12-01

    utility of the new rate calculation methods and for comparison with the previously used rate methods.

  8. Video rate passive millimeter-wave imager utilizing optical upconversion with improved size, weight, and power

    NASA Astrophysics Data System (ADS)

    Martin, Richard D.; Shi, Shouyuan; Zhang, Yifei; Wright, Andrew; Yao, Peng; Shreve, Kevin P.; Schuetz, Christopher A.; Dillon, Thomas E.; Mackrides, Daniel G.; Harrity, Charles E.; Prather, Dennis W.

    2015-05-01

    In this presentation we will discuss the performance and limitations of our 220 channel video rate passive millimeter wave imaging system based on a distributed aperture with optical upconversion architecture. We will cover our efforts to reduce the cost, size, weight, and power (CSWaP) requirements of our next generation imager. To this end, we have developed custom integrated circuit silicon-germanium (SiGe) low noise amplifiers that have been designed to efficiently couple with our high performance lithium niobate upconversion modules. We have also developed millimeter wave packaging and components in multilayer liquid crystal polymer (LCP) substrates which greatly improve the manufacturability of the upconversion modules. These structures include antennas, substrate integrated waveguides, filters, and substrates for InP and SiGe mmW amplifiers.

  9. Heart rate dynamics in patients with stable angina pectoris and utility of fractal and complexity measures

    NASA Technical Reports Server (NTRS)

    Makikallio, T. H.; Ristimae, T.; Airaksinen, K. E.; Peng, C. K.; Goldberger, A. L.; Huikuri, H. V.

    1998-01-01

    Dynamic analysis techniques may uncover abnormalities in heart rate (HR) behavior that are not easily detectable with conventional statistical measures. However, the applicability of these new methods for detecting possible abnormalities in HR behavior in various cardiovascular disorders is not well established. Conventional measures of HR variability were compared with short-term (< or = 11 beats, alpha1) and long-term (> 11 beats, alpha2) fractal correlation properties and with approximate entropy of RR interval data in 38 patients with stable angina pectoris without previous myocardial infarction or cardiac medication at the time of the study and 38 age-matched healthy controls. The short- and long-term fractal scaling exponents (alpha1, alpha2) were significantly higher in the coronary patients than in the healthy controls (1.34 +/- 0.15 vs 1.11 +/- 0.12 [p <0.001] and 1.10 +/- 0.08 vs 1.04 +/- 0.06 [p <0.01], respectively), and they also had lower approximate entropy (p <0.05), standard deviation of all RR intervals (p <0.01), and high-frequency spectral component of HR variability (p <0.05). The short-term fractal scaling exponent performed better than other heart rate variability parameters in differentiating patients with coronary artery disease from healthy subjects, but it was not related to the clinical or angiographic severity of coronary artery disease or any single nonspectral or spectral measure of HR variability in this retrospective study. Patients with stable angina pectoris have altered fractal properties and reduced complexity in their RR interval dynamics relative to age-matched healthy subjects. Dynamic analysis may complement traditional analyses in detecting altered HR behavior in patients with stable angina pectoris.

  10. A comparison of the relation between oxygen uptake and heart rate during different styles of aerobic dance and a traditional step test in women.

    PubMed

    Bell, J M; Bassey, E J

    1994-01-01

    The oxygen uptake and heart rate in various styles of dance and in a graded step test have been compared in ten healthy women aged [mean (SD)] 34 (5) years. Dance was choreographed into progressively more energetic sequences typical of community classes, and videotaped. Oxygen uptake was assessed using a respirometer carried in a back-pack. Each of the two tests (dance and step) took 15-20 min and measurements were made in randomised balanced order on the same day. The mean oxygen costs of dance ranged from 1.29 l.min-1 for low impact style to 1.83 l.min-1 for high impact style with arm work; mean heart rates were 135 and 174 beats.min-1 respectively. Low impact dance raised heart rates above 60% of predicted maximum and so would provide training; during high impact dance recorded heart rates sometimes exceeded recommended safe limits. The addition of arm work significantly increased heart rates in both high and low impact dance but when oxygen pulses for each style of dance were compared no significant differences attributable to arm work were found. Moreover calculated differences between oxygen uptakes in stepping and dance at the same heart rates (those recorded during dance) were not significant for any of the four styles. Analysis of variance confirmed that neither arm work nor impact contributed significantly to the differences, so there was no evidence that these forms of dance change the normal relation between heart rate and oxygen uptake found in dynamic activities with large muscle groups such as stepping. PMID:8162917

  11. Appropriateness of primary total hip and knee replacements in regions of Ontario with high and low utilization rates.

    PubMed Central

    van Walraven, C V; Paterson, J M; Kapral, M; Chan, B; Bell, M; Hawker, G; Gollish, J; Schatzker, J; Williams, J I; Naylor, C D

    1996-01-01

    OBJECTIVE: To compare the appropriateness of case selection for primary hip and knee replacements between two regions in Ontario: one with a high population-based utilization rate and one with a low rate. DESIGN: Random audit of medical records sampled from hospital discharge abstracts, with subsequent implicit and explicit criteria-based assessments of the appropriateness of surgery. STUDY POPULATION: People aged 60 years or over who underwent elective, single-joint, non-fracture-related, primary hip or knee replacement between Apr. 1, 1992, and Mar. 31, 1993, at one of seven hospitals in a high-rate region (comprising Brant, Huron and Oxford countries) or one of eight hospitals in a low-rate region (comprising the cities of Scarborough and Toronto). INTERVENTIONS: Structured review of hospital medical records, with additional review of information from surgeons and family physicians' office charts if necessary. Three physicians reviewed patient data and rated the preoperative pain level and functional status of patients, with agreement among at least two reviewers. The proportion of inappropriate cases was then assessed according to explicit criteria defined by a multidisciplinary panel using the delphi process. Profiles of each case were also subjected to independent implicit review by two rheumatologists and two orthopedic surgeons. OUTCOME MEASURES: Proportion of joint replacements deemed inappropriate in the high- and low-rate regions according to either the explicit criteria or the implicit review, as well as preoperative pain levels and functional status of patients in the high- and low-rate regions. RESULTS: Hip replacements were more common among patients sampled in the low-rate region than among those in the high-rate region (57.3% v. 39.3%; p < 0.002), although the patients' baseline characteristics, including severity of preoperative pain and dysfunction, were otherwise similar between the regions. Inappropriate surgery, determined by explicit criteria

  12. Healing rates for challenging rotator cuff tears utilizing an acellular human dermal reinforcement graft

    PubMed Central

    Agrawal, Vivek

    2012-01-01

    Purpose: This study presents a retrospective case series of the clinical and structural outcomes (1.5 T MRI) of arthroscopic rotator cuff repair with acellular human dermal graft reinforcement performed by a single surgeon in patients with large, massive, and previously repaired rotator cuff tears. Materials and Methods: Fourteen patients with mean anterior to posterior tear size 3.87 ± 0.99 cm (median 4 cm, range 2.5–6 cm) were enrolled in the study and were evaluated for structural integrity using a high-field (1.5 T) MRI at an average of 16.8 months after surgery. The Constant-Murley scores, the Flexilevel Scale of Shoulder Function (Flex SF), scapular plane abduction, and strength were analyzed. Results: MRI results showed that the rotator cuff repair was intact in 85.7% (12/14) of the patients studied. Two patients had a Sugaya Type IV recurrent tear (2 of 14; 14.3%), which were both less than 1 cm. The Constant score increased from a preoperative mean of 49.72 (range 13–74) to a postoperative mean of 81.07 (range 45–92) (P value = 0.009). Flexilevel Scale of Shoulder Function (Flex SF) Score normalized to a 100-point scale improved from a preoperative mean of 53.69 to a postoperative mean of 79.71 (P value = 0.003). The Pain Score improved from a preoperative mean of 7.73 to a postoperative mean of 13.57 (P value = 0.008). Scapular plane abduction improved from a preoperative mean of 113.64° to a postoperative mean of 166.43° (P value = 0.010). The strength subset score improved from a preoperative mean of 1.73 kg to a postoperative mean of 7.52 kg (P value = 0.006). Conclusions: This study presents a safe and effective technique that may help improve the healing rates of large, massive, and revision rotator cuff tears with the use of an acellular human dermal allograft. This technique demonstrated favorable structural healing rates and statistically improved functional outcomes in the near term. Level of Evidence: 4. Retrospective case series. PMID

  13. Strain energy release rate as a function of temperature and preloading history utilizing the edge delamination fatique test method

    NASA Technical Reports Server (NTRS)

    Zimmerman, Richard S.; Adams, Donald F.

    1989-01-01

    Static laminate and tension-tension fatigue tests of IM7/8551-7 composite materials was performed. The Edge Delamination Test (EDT) was utilized to evaluate the temperature and preloading history effect on the critical strain energy release rate. Static and fatigue testing was performed at room temperature and 180 F (82 C). Three preloading schemes were used to precondition fatigue test specimens prior to performing the normal tension-tension fatigue EDT testing. Computer software was written to perform all fatigue testing while monitoring the dynamic modulus to detect the onset of delamination and record the test information for later retrieval and reduction.

  14. Evaluation of a Stirling Solar Dynamic System for Lunar Oxygen Production

    NASA Technical Reports Server (NTRS)

    Colozza, Anthony J.; Wong, Wayne A.

    2006-01-01

    An evaluation of a solar concentrator-based system for producing oxygen from the lunar regolith was performed. The system utilizes a solar concentrator mirror to provide thermal energy for the oxygen production process as well as thermal energy to power a Stirling heat engine for the production of electricity. The electricity produced is utilized to operate the equipment needed in the oxygen production process. The oxygen production method utilized in the analysis was the hydrogen reduction of ilmenite. Utilizing this method of oxygen production a baseline system design was produced. This baseline system had an oxygen production rate of 0.6 kg/hr with a concentrator mirror size of 5 m. Variations were performed on the baseline design to show how changes in the system size and process rate effected the oxygen production rate.

  15. Role of Oxygen in the Limitation and Inhibition of Nitrogenase Activity and Respiration Rate in Individual Soybean Nodules.

    PubMed Central

    Kuzma, M. M.; Hunt, S.; Layzell, D. B.

    1993-01-01

    Although infected cell O2 concentration (Oi) is known to limit respiration and nitrogenase activity in legume nodules, techniques have not been available to measure both processes simultaneously in an individual legume nodule. Consequently, details of the relationship between nitrogenase activity and Oi are not fully appreciated. For the present study, a probe was designed that allowed open circuit measurements of H2 evolution (nitrogenase activity) and CO2 evolution (respiration rate) in a single attached soybean nodule while simultaneously monitoring fractional oxygenation of leghemoglobin (and thereby Oi) with a nodule oximeter. Compared to measurements of whole nodulated roots, use of the probe led to inhibition of nitrogenase activity in the single nodules. During oximetry measurements, total nitrogenase activity (TNA; peak H2 evolution in Ar/O2) in the single nodules was 16% of that in whole nodulated roots and 48% of nodulated root activity when Oi was not being measured simultaneously. This inhibition did not affect the nodules' ability to regulate Oi, because exposure to Ar/O2 (80:20, v/v) caused nitrogenase activity and respiration rate to decline, and this decline was linearly correlated with a concurrent decrease in Oi. When the nodules were subsequently exposed to a linear increase in external pO2 from 20 to 100% O2 at 2.7% O2/min, fractional leghemoglobin oxygenation first increased gradually and then more rapidly, reaching saturation at a pO2 between 76 and 100% O2. Plots of nitrogenase activity and respiration rate against Oi showed that rates increased with Oi up to a value of 57 nM, with half-maximal rates being attained at Oi values between 10 and 14 nM O2. The maximum nitrogenase activity achieved during the increase in pO2 (potential nitrogenase activity) was 30 to 57% of that measured in intact nodulated roots, showing that O2 limitation of nitrogenase activity could account for a significant proportion of the inhibition of TNA associated with

  16. Source Anonymity in WSNs against Global Adversary Utilizing Low Transmission Rates with Delay Constraints.

    PubMed

    Bushnag, Anas; Abuzneid, Abdelshakour; Mahmood, Ausif

    2016-01-01

    Wireless sensor networks (WSN) are deployed for many applications such as tracking and monitoring of endangered species, military applications, etc. which require anonymity of the origin, known as Source Location Privacy (SLP). The aim in SLP is to prevent unauthorized observers from tracing the source of a real event by analyzing the traffic in the network. Previous approaches to SLP such as Fortified Anonymous Communication Protocol (FACP) employ transmission of real or fake packets in every time slot, which is inefficient. To overcome this shortcoming, we developed three different techniques presented in this paper. Dummy Uniform Distribution (DUD), Dummy Adaptive Distribution (DAD) and Controlled Dummy Adaptive Distribution (CAD) were developed to overcome the anonymity problem against a global adversary (which has the capability of analyzing and monitoring the entire network). Most of the current techniques try to prevent the adversary from perceiving the location and time of the real event whereas our proposed techniques confuse the adversary about the existence of the real event by introducing low rate fake messages, which subsequently lead to location and time privacy. Simulation results demonstrate that the proposed techniques provide reasonable delivery ratio, delay, and overhead of a real event's packets while keeping a high level of anonymity. Three different analysis models are conducted to verify the performance of our techniques. A visualization of the simulation data is performed to confirm anonymity. Further, neural network models are developed to ensure that the introduced techniques preserve SLP. Finally, a steganography model based on probability is implemented to prove the anonymity of the techniques. PMID:27355948

  17. Source Anonymity in WSNs against Global Adversary Utilizing Low Transmission Rates with Delay Constraints

    PubMed Central

    Bushnag, Anas; Abuzneid, Abdelshakour; Mahmood, Ausif

    2016-01-01

    Wireless sensor networks (WSN) are deployed for many applications such as tracking and monitoring of endangered species, military applications, etc. which require anonymity of the origin, known as Source Location Privacy (SLP). The aim in SLP is to prevent unauthorized observers from tracing the source of a real event by analyzing the traffic in the network. Previous approaches to SLP such as Fortified Anonymous Communication Protocol (FACP) employ transmission of real or fake packets in every time slot, which is inefficient. To overcome this shortcoming, we developed three different techniques presented in this paper. Dummy Uniform Distribution (DUD), Dummy Adaptive Distribution (DAD) and Controlled Dummy Adaptive Distribution (CAD) were developed to overcome the anonymity problem against a global adversary (which has the capability of analyzing and monitoring the entire network). Most of the current techniques try to prevent the adversary from perceiving the location and time of the real event whereas our proposed techniques confuse the adversary about the existence of the real event by introducing low rate fake messages, which subsequently lead to location and time privacy. Simulation results demonstrate that the proposed techniques provide reasonable delivery ratio, delay, and overhead of a real event's packets while keeping a high level of anonymity. Three different analysis models are conducted to verify the performance of our techniques. A visualization of the simulation data is performed to confirm anonymity. Further, neural network models are developed to ensure that the introduced techniques preserve SLP. Finally, a steganography model based on probability is implemented to prove the anonymity of the techniques. PMID:27355948

  18. Clinical utility of high-flow nasal cannula oxygen therapy for acute respiratory failure in patients with hematological disease.

    PubMed

    Harada, Kaito; Kurosawa, Shuhei; Hino, Yutaro; Yamamoto, Keita; Sakaguchi, Masahiro; Ikegawa, Shuntaro; Hattori, Keiichro; Igarashi, Aiko; Watakabe, Kyoko; Senoo, Yasushi; Najima, Yuho; Hagino, Takeshi; Doki, Noriko; Kobayashi, Takeshi; Kakihana, Kazuhiko; Iino, Toshihiro; Sakamaki, Hisashi; Ohashi, Kazuteru

    2016-01-01

    A high-flow nasal cannula (HFNC) is a newly developed device that enables high-flow oxygen therapy for patients with serious cardiopulmonary problems, but there are few data regarding its use in patients with hematological disease. The efficacy and tolerability of HFNCs for patients who developed ARF during the treatment of various hematological diseases was evaluated. Fifty-six patients underwent HFNC therapy during the last 2 years, and the causes of ARF were mainly pneumonia (n = 37) or acute congestive heart failure (n = 7). Only 11 patients (20 %) showed a good response to HFNC therapy, and remaining 45 patients (80 %) failed to respond to the initial HFNC therapy and, therefore, underwent second-line therapy including endotracheal intubation with mechanical ventilation (n = 15), non-invasive positive pressure ventilation (n = 1), or narcotic palliation alone (n = 29). Thus, HFNC appear not to be a viable treatment option in 4 out of 5 patients in this cohort of patients with hematological disease, but it was well tolerated in most patients (96 %); no major complications except for nasal soreness (n = 2) were observed. Multivariate analysis showed that the cause of ARF (pneumonia, odds ratio 11.2, 95 % CI 1.76-71.5, p = 0.01) was the only risk factor for treatment failure. PMID:27186476

  19. Utilization of multi-band OFDM modulation to increase traffic rate of phosphor-LED wireless VLC.

    PubMed

    Yeh, Chien-Hung; Chen, Hsing-Yu; Chow, Chi-Wai; Liu, Yen-Liang

    2015-01-26

    To increase the traffic rate in phosphor-LED visible light communication (VLC), a multi-band orthogonal frequency division multiplexed (OFDM) modulation is first proposed and demonstrated. In the measurement, we do not utilize optical blue filter to increase modulation bandwidth of phosphor-LED in the VLC system. In this proposed scheme, different bands of OFDM signals are applied to different LED chips in a LED lamp, this can avoid the power fading and nonlinearity issue by applying the same OFDM signal to all the LED chips in a LED lamp. Here, the maximum increase percentages of traffic rates are 41.1%, 17.8% and 17.8% under received illuminations of 200, 500 and 1000 Lux, respectively, when the proposed three-band OFDM modulation is used in the VLC system. In addition, the analysis and verification by experiments are also performed. PMID:25835873

  20. Calculated volatilization rates of fuel oxygenate compounds and other gasoline-related compounds from rivers and streams

    USGS Publications Warehouse

    Pankow, J.F.; Rathbun, R.E.; Zogorski, J.S.

    1996-01-01

    Large amounts of the 'fuel-oxygenate' compound methyl-tert-butyl ether (MTBE) are currently being used in gasoline to reduce carbon monoxide and ozone in urban air and to boost fuel octane. Because MTBE can be transported to surface waters in various ways, established theory was used to calculate half-lives for MTBE volatilizing from flowing surface waters. Similar calculations were made for benzene as a representative of the 'BTEX' group of compounds (benzene, toluene, ethyl benzene, and the xylenes), and for tert-butyl alcohol (TBA). The calculations were made as a function of the mean flow velocity u (m/day), the mean flow depth h (m), the ambient temperature, and the wind speed. In deep, slow-moving flows, MTBE volatilizes at rates which are similar to those for the BTEX compounds. In shallow, fast-moving flows, MTBE volatilizes more slowly than benzene, though in such flows both MTBE and benzene volatilize quickly enough that these differences may often not have much practical significance. TBA was found to be essentially nonvolatile from water.

  1. Direct estimation of cardiac reserve through analysis of relation between oxygen consumption and heart rate during exercise testing.

    PubMed

    Sunagawa, H; Honda, S; Yoshii, K; Mizoguchi, Y; Fukuda, S; Iwao, H

    1985-12-01

    In order to elucidate fundamental relationship between exercise and cardiac reserve, we investigated the parameters of regression equation (VO2 = A X HR + B) between oxygen consumption (VO2 ml/kg/min) and heart rate (HR) during exercise test (Bruce). 62 male children were divided into 3 groups based on history and clinical evaluation. HR related linearly with VO2 (average r = 0.967, range 0.90-0.993). Both of the parameters A and [B] were significantly high in Athlete (A = 0.465 +/- 0.043, [B] = 36 +/- 6.07), low in Failed (0.297 +/- 0.055, 17.4 +/- 6.1) and middle in Ordinary group (0.366 +/- 0.078, 23.5 +/- 8.6) (p less than 0.005). Based on our result of linear VO2-HR relation, and on the previously reported studies that cardiac output linearly and consistently relates with VO2, we considered the meaning of the parameters as follows; A determines the possible maximum stroke volume (SV), and B determines the HR where SV reaches plateau. In conclusion, since the SV is considered as a measure of cardiac function, measuring the parameters of VO2-HR relation allows us to isolate cardiac functional reserve through the exercise tolerance test. PMID:3831400

  2. Physiological significance of the slope of the regression equation between oxygen consumption and heart rate in exercise testing.

    PubMed

    Sunagawa, H; Honda, S; Mizoguchi, Y; Yoshii, K; Iwao, H

    1984-12-01

    The relationship between oxygen consumption (VO2) and heart rate (HR) was studied in 62 male children. Based on clinical evaluation and history, they were divided into three groups, i.e., athlete, ordinary and failed. There was a high linear correlation between HR and VO2 in each individual. The averaged values of the slope and standard deviations were 2.09 +/- 0.189 in the athlete group (n = 17), 2.60 +/- 0.140 in the ordinary group (n = 16) and 3.17 +/- 0.591 in the failed group (n = 29). The statistical differences were confirmed among the groups (p less than 0.005). The results suggested that the slope of the HR vs. VO2 relation was related to an inotropic state of cardiac function. We concluded that the slope was a more suitable and more direct evaluation of cardiac function during exercise. Moreover, the method was non-invasive and safe because it required no potentially hazardous maximum work load for the patients. PMID:6512949

  3. Measuring the activities of higher organisms in activated sludge by means of mechanical shearing pretreatment and oxygen uptake rate.

    PubMed

    Hao, Xiaodi; Wang, Qilin; Cao, Yali; van Loosdrecht, Mark C M

    2010-07-01

    A pretreatment method was developed to assess the activities of higher organisms. The method is based on mechanical shearing to damage the large cells of the protozoan and metazoan community in activated sludge. The procedure was confirmed through experimentation to be effective in determining the activities of higher organisms by comparing oxygen uptake rates (OURs) before and after the higher organisms were eradicated. Shearing led to disintegration of flocs, which could be effectively reconstituted by centrifugation. The reconstitution of the sludge flocs was essential since otherwise the activity of the floc mass would be too high due to lack of diffusion limitation. Mechanical shearing had no influence on the morphology, quantity and specific activity of yeasts, and it was inferred that bacteria smaller than yeasts in size would also not be influenced by the applied shearing procedure. Moreover, the effect of filamentous organisms on the measured activities of higher organisms was experimentally demonstrated and analyzed, and determined to be so weak that it could be ignored. Based on these tests, five typical activated sludge processes were selected to measure the contribution of higher organisms to the original OUR. The measured activities of higher organisms ranged from 9.4 to 25.0% of the original OURs. PMID:20605188

  4. Temporal changes and spatial variation of soil oxygen consumption, nitrification and denitrification rates in a tidal salt marsh of the Lagoon of Venice, Italy

    NASA Astrophysics Data System (ADS)

    Eriksson, P. G.; Svensson, J. M.; Carrer, G. M.

    2003-12-01

    The aim of the present study was to investigate seasonal and spatial patterns of soil oxygen consumption, nitrification, denitrification and fluxes of dissolved inorganic nitrogen (DIN) in a tidal salt marsh of the Lagoon of Venice, Italy. In the salt marsh, intact soil cores including overlying water were collected monthly at high tide from April to October in salt marsh creeks and in areas covered by the dominant vegetation, Limonium serotinum. In May, cores were also collected in areas with vegetation dominated by Juncus maritimus and Halimione portulacoides. In laboratory incubations at in situ temperature in the dark, flux rates of oxygen and DIN were monitored in the overlying water of the intact cores. 15N-nitrate was added to the overlying water and nitrification and denitrification were measured using isotope-dilution and -pairing techniques. The results show that highest soil oxygen consumption coincided with the highest water temperature in June and July. The highest denitrification rates were recorded in spring and autumn coinciding with the highest nitrate concentrations. Soil oxygen consumption and nitrification rates differed between sampling sites, but denitrification rates were similar among the different vegetation types. The highest rates were recorded in areas covered with L. serotinum. Burrowing soil macrofauna enhanced oxygen consumption, nitrification and denitrification in April and May. The data presented in this study indicate high temporal as well as spatial variations in the flux of oxygen and DIN, and nitrogen transformations in the tidal salt marshes of the Venice lagoon during the growth season. The results identify the salt marshes of the Venice lagoon as being metabolically very active ecosystems with a high capacity to process nitrogen.

  5. Characteristics Evaluation of a CO2-Caputuring Power Generation System with Reheat Cycle Utilizing Regenerative Oxygen-Combustion Steam-Superheater

    NASA Astrophysics Data System (ADS)

    Pak, Pyong Sik

    A new CO2-capturing power generation system is proposed that can be easily realized by applying conventional technologies. In the proposed system, the temperature of middle-pressure steam in a thermal power plant is raised by utilizing oxygen-combusting regenerative steam-superheater. The generated CO2 by combusting fuel in the superheater can be easily separated and captured from the exhaust gas at condenser outlet, and is liquefied. The superheated steam is used to drive a steam turbine power generation system. By adopting a high efficient combined cycle power generation system as an example, it has been shown that the proposed system can increase power output by 10.8%, decrease the CO2 emission amount of the total integrated system by 18.6% with power generation efficiency drop of 2.36% compared with the original power plant without CO2-capture, when superheated steam temperature is 750°C

  6. The multi-year cumulative effects of alternative stocking rate and grazing management practices on pasture productivity and utilization efficiency.

    PubMed

    McCarthy, B; Delaby, L; Pierce, K M; McCarthy, J; Fleming, C; Brennan, A; Horan, B

    2016-05-01

    The production and utilization of increased quantities of high quality pasture is of paramount importance in pasture-based milk production systems. The objective of this study was to evaluate the cumulative effects of alternative integrated grazing strategies, incorporating alternative stocking rate (SR) and grazing severities, on pasture productivity and grazing efficiency over multiple years within farm systems using perennial ryegrass dominant pastures. Three whole-farm SR treatments were compared over 4 complete grazing seasons (2009 to 2012 inclusive): low (2.51 cows/ha; LSR), medium (2.92 cows/ha; MSR), and high (3.28 cows/ha; HSR). Each system had its own farmlet containing 18 paddocks and remained on the same treatment for the duration of the study. Stocking rate had a significant effect on all grazing variables with the exception of soil fertility status and sward density. Increased SR resulted in increased total annual net pasture accumulation, improved sward nutritive value, and increased grazed pasture utilization. Total annual net pasture accumulation was greatest in HSR [15,410kg of dry matter (DM)/ha], intermediate for MSR (14,992kg of DM/ha), and least for LSR (14,479kg of DM/ha) during the 4-yr study period. A linear effect of SR on net pasture accumulation was detected with an increase in net pasture accumulation of 1,164.4 (SE=432.7) kg of DM/ha for each 1 cow/ha increase in SR. Pregrazing pasture mass and height and postgrazing residual pasture mass and height were greatest for LSR, intermediate for the MSR, and lowest for the HSR. In comparison with the LSR, the imposition of a consistently increased grazing severity coupled with increased whole farm SR in MSR and HSR treatments arrested the decline in sward nutritive value, typically observed during mid-season. Incorporating the individual beneficial effects of SR on pasture accumulation, nutritive value, and utilization efficiency, total proportional energy (unité fourragère lait

  7. Bladder Preservation for Localized Muscle-Invasive Bladder Cancer: The Survival Impact of Local Utilization Rates of Definitive Radiotherapy

    SciTech Connect

    Kozak, Kevin R.; Hamidi, Maryam; Manning, Matthew; Moody, John S.

    2012-06-01

    Purpose: This study examines the management and outcomes of muscle-invasive bladder cancer in the United States. Methods and Materials: Patients with muscle-invasive bladder cancer diagnosed between 1988 and 2006 were identified in the Surveillance, Epidemiology, and End Results (SEER) database. Patients were classified according to three mutually exclusive treatment categories based on the primary initial treatment: no local management, radiotherapy, or surgery. Overall survival was assessed with Kaplan-Meier analysis and Cox models based on multiple factors including treatment utilization patterns. Results: The study population consisted of 26,851 patients. Age, sex, race, tumor grade, histology, and geographic location were associated with differences in treatment (all p < 0.01). Patients receiving definitive radiotherapy tended to be older and have less differentiated tumors than patients undergoing surgery (RT, median age 78 years old and 90.6% grade 3/4 tumors; surgery, median age 71 years old and 77.1% grade 3/4 tumors). No large shifts in treatment were seen over time, with most patients managed with surgical resection (86.3% for overall study population). Significant survival differences were observed according to initial treatment: median survival, 14 months with no definitive local treatment; 17 months with radiotherapy; and 43 months for surgery. On multivariate analysis, differences in local utilization rates of definitive radiotherapy did not demonstrate a significant effect on overall survival (hazard ratio, 1.002; 95% confidence interval, 0.999-1.005). Conclusions: Multiple factors influence the initial treatment strategy for muscle-invasive bladder cancer, but definitive radiotherapy continues to be used infrequently. Although patients who undergo surgery fare better, a multivariable model that accounted for patient and tumor characteristics found no survival detriment to the utilization of definitive radiotherapy. These results support continued

  8. Simultaneous evaluation of substrate-dependent oxygen consumption rates and mitochondrial membrane potential by TMRM and safranin in cortical mitochondria

    PubMed Central

    Chowdhury, Subir Roy; Djordjevic, Jelena; Albensi, Benedict C.; Fernyhough, Paul

    2015-01-01

    Mitochondrial membrane potential (mtMP) is critical for maintaining the physiological function of the respiratory chain to generate ATP. The present study characterized the inter-relationship between mtMP, using safranin and tetramethyl rhodamine methyl ester (TMRM), and mitochondrial respiratory activity and established a protocol for functional analysis of mitochondrial bioenergetics in a multi-sensor system. Coupled respiration was decreased by 27 and 30–35% in the presence of TMRM and safranin respectively. Maximal respiration was higher than coupled with Complex I- and II-linked substrates in the presence of both dyes. Safranin showed decreased maximal respiration at a higher concentration of carbonyl cyanide-4-(trifluoromethoxy)phenylhydrazone (FCCP) compared with TMRM. FCCP titration revealed that maximal respiration in the presence of glutamate and malate was not sustainable at higher FCCP concentrations as compared with pyruvate and malate. Oxygen consumption rate (OCR) and mtMP in response to mitochondrial substrates were higher in isolated mitochondria compared with tissue homogenates. Safranin exhibited higher sensitivity to changes in mtMP than TMRM. This multi-sensor system measured mitochondrial parameters in the brain of transgenic mice that model Alzheimer's disease (AD), because mitochondrial dysfunction is believed to be a primary event in the pathogenesis of AD. The coupled and maximal respiration of electron transport chain were decreased in the cortex of AD mice along with the mtMP compared with age-matched controls. Overall, these data demonstrate that safranin and TMRM are suitable for the simultaneous evaluation of mtMP and respiratory chain activity using isolated mitochondria and tissue homogenate. However, certain care should be taken concerning the selection of appropriate substrates and dyes for specific experimental circumstances. PMID:26647379

  9. [Deep hypotension induced by sodium nitroprusside in neurosurgery. II.--Cerebral hemodynamic effects and metabolic rate of oxygen (author's transl)].

    PubMed

    Pinaud, M; Souron, R; Gazeau, M F; Lajat, Y; Chatal, J F; Nicolas, F

    1979-01-01

    The cerebral hemodynamic effects of sodium nitroprusside (S. N.) have been the object of animal studies mainly. During the only human study performed, the drop in mean arterial pressure (MAP) is limited to 67 mm Hg. The study of the evolution of cerebral blood flow (CBF) in cases of more severe hypotension (MAP less than 45 mm Hg) seems of some interest. The study was composed of the measurement of the CBF using Xenon 133 and the calculation of cerebral vascular resistances (CVR) as well as cerebral metabolic rate of oxygen (CMRO2). Eleven patients with an average age of 37 years underwent surgery for cerebral aneurism 10 to 15 days after the inaugural hemorrhagic accident, under narconeuroleptanalgesia and stable ventilatory conditions. They are divided into 2 groups: Group I, 9 patients with normal levels of consciousness; Group II, 2 patients either agitated or obnubilated. The study is composed of 3 successive measures: (1) (T0) during stable anesthesia just prior to hypotension; (2) (T1) after 5 minutes of hypotension (MAP = 40 +/- 7 MM Hg); (3) (T2) 20 minutes after having stopped S. N. infusion. For the 9 patients in Group I, CBF remains unchanged at T1, the CVR decreases (p less than 0.001) and CMRO2 decreases (p less than 0.05). At T2 all of these parameters return to T0 values. The postoperative clinical evolution is favorable and uncomplicated. For the 2 patients in Group II the CBF, initially higher, falls from 20 to 30 p. cent at T1 with a drastic reduction in CMRO2. Despite the improvement of these parameters at T2, a prolonged postoperative coma is observed. This study suggests that CBF and CMRO2 are important parameters to monitor during controlled severe hypotension. Decrease in MAP must be less than 50 p. cent of control value and time-limited. PMID:484888

  10. Simultaneous evaluation of substrate-dependent oxygen consumption rates and mitochondrial membrane potential by TMRM and safranin in cortical mitochondria.

    PubMed

    Chowdhury, Subir Roy; Djordjevic, Jelena; Albensi, Benedict C; Fernyhough, Paul

    2016-01-01

    Mitochondrial membrane potential (mtMP) is critical for maintaining the physiological function of the respiratory chain to generate ATP. The present study characterized the inter-relationship between mtMP, using safranin and tetramethyl rhodamine methyl ester (TMRM), and mitochondrial respiratory activity and established a protocol for functional analysis of mitochondrial bioenergetics in a multi-sensor system. Coupled respiration was decreased by 27 and 30-35% in the presence of TMRM and safranin respectively. Maximal respiration was higher than coupled with Complex I- and II-linked substrates in the presence of both dyes. Safranin showed decreased maximal respiration at a higher concentration of carbonyl cyanide-4-(trifluoromethoxy)phenylhydrazone (FCCP) compared with TMRM. FCCP titration revealed that maximal respiration in the presence of glutamate and malate was not sustainable at higher FCCP concentrations as compared with pyruvate and malate. Oxygen consumption rate (OCR) and mtMP in response to mitochondrial substrates were higher in isolated mitochondria compared with tissue homogenates. Safranin exhibited higher sensitivity to changes in mtMP than TMRM. This multi-sensor system measured mitochondrial parameters in the brain of transgenic mice that model Alzheimer's disease (AD), because mitochondrial dysfunction is believed to be a primary event in the pathogenesis of AD. The coupled and maximal respiration of electron transport chain were decreased in the cortex of AD mice along with the mtMP compared with age-matched controls. Overall, these data demonstrate that safranin and TMRM are suitable for the simultaneous evaluation of mtMP and respiratory chain activity using isolated mitochondria and tissue homogenate. However, certain care should be taken concerning the selection of appropriate substrates and dyes for specific experimental circumstances. PMID:26647379

  11. Self-Rating of the Effects of Alcohol (SRE): Predictive utility and reliability across interview and self-report administrations.

    PubMed

    Ray, Lara A; Hart, Eliza J; Chin, Pauline F

    2011-03-01

    The Self-Rating of the Effects of Alcohol (SRE) is a widely used and well-established measure of the level of response to alcohol. Although the SRE has been successfully used in studies of alcoholism etiology, including genetics, studies to date have not compared the self-report and interview formats. The objectives of this study are to: (a) test the predictive utility of the subscales of the SRE in relation to alcohol problems; and (b) test the reliability of the SRE in interview versus self-report formats. A sample of college drinkers (n=446) completed the SRE in a self-report format along with the Alcohol Use Disorders Identification Test (AUDIT). A subset of participants (n=34) returned to the laboratory and completed the SRE in a face-to-face interview format. All subscales of the SRE were robust predictors of alcohol problems accounting for as much as 25% of the variance in AUDIT scores. In addition, scores obtained via self-report and interview-based SRE were highly correlated (r=.70 to .80). Results support the predictive utility of the SRE and provide initial evidence that the self-report and interview formats produce reliable results and may be combined and/or used interchangeably. PMID:21095629

  12. Wii, Kinect, and Move. Heart Rate, Oxygen Consumption, Energy Expenditure, and Ventilation due to Different Physically Active Video Game Systems in College Students

    PubMed Central

    SCHEER, KRISTA S.; SIEBRANT, SARAH M.; BROWN, GREGORY A.; SHAW, BRANDON S.; SHAW, INA

    2014-01-01

    Nintendo Wii, Sony Playstation Move, and Microsoft XBOX Kinect are home video gaming systems that involve player movement to control on-screen game play. Numerous investigations have demonstrated that playing Wii is moderate physical activity at best, but Move and Kinect have not been as thoroughly investigated. The purpose of this study was to compare heart rate, oxygen consumption, and ventilation while playing the games Wii Boxing, Kinect Boxing, and Move Gladiatorial Combat. Heart rate, oxygen consumption, and ventilation were measured at rest and during a graded exercise test in 10 males and 9 females (19.8 ± 0.33 y, 175.4 ± 2.0 cm, 80.2 ± 7.7 kg,). On another day, in a randomized order, the participants played Wii Boxing, Kinect Boxing, and Move Gladiatorial Combat while heart rate, ventilation, and oxygen consumption were measured. There were no differences in heart rate (116.0 ± 18.3 vs. 119.3 ± 17.6 vs. 120.1 ± 17.6 beats/min), oxygen consumption (9.2 ± 3.0 vs. 10.6 ± 2.4 vs. 9.6 ± 2.4 ml/kg/min), or minute ventilation (18.9 ± 5.7 vs. 20.8 ± 8.0 vs. 19.7 ± 6.4 L/min) when playing Wii boxing, Kinect boxing, or Move Gladiatorial Combat (respectively). Playing Nintendo Wii Boxing, XBOX Kinect Boxing, and Sony PlayStation Move Gladiatorial Combat all increase heart rate, oxygen consumption, and ventilation above resting levels but there were no significant differences between gaming systems. Overall, playing a “physically active” home video game system does not meet the minimal threshold for moderate intensity physical activity, regardless of gaming system. PMID:27182399

  13. Net Community and Gross Photosynthetic Production Rates in the Eastern Tropical South Pacific, as Determined from O2/AR Ratios and Triple Oxygen Isotopic Composition of Dissolved O2

    NASA Astrophysics Data System (ADS)

    Prokopenko, M. G.; Yeung, L. Y.; Berelson, W.; Fleming, J.; Rollins, N.; Young, E. D.; Haskell, W. Z.; Hammond, D. E.; Capone, D. G.

    2010-12-01

    This study assesses the rates of ocean carbon production and its fate with respect to recycling or export in the Eastern Tropical South Pacific (ETSP). ETSP has been previously identified as a region where N2 fixation and denitrification may be spatially coupled; this is also a region of localized CO2 outgassing. Using an Equilibrated Inlet Mass Spectrometer (EIMS) system, we obtained continuous measurements of the biological O2 supersaturation in the mixed layer along the ship track encompassing a region bounded by 10-20° S and 80-100° W in January - March, 2010. Vertical profiles were also taken at selected stations and analyzed for dissolved O2/Ar ratios on EIMS and triple oxygen isotope composition (17O excess) on a multi-collector IRMS (Isotope Ratio Mass Spectrometer) at UCLA. Gas exchange rates were estimated using two approaches: the Rn-222 deficit method and the wind parameterization method, which utilized wind speeds extracted from ASCAT satellite database. Oxygen Net Community Production (O-NCP) rates calculated based on biological O2 supersaturation ranged from slightly negative to ~ 0.3 - 15 mmol/m2d, with higher rates along the northern part of the transect. Oxygen Gross Community Production (O-GPP) rates calculated from 17O excess were between 50 ± 20 and 200 ± 40 mmol/m2d, with higher rates observed along the northern cruise transect as well. Notably, the NCP/GPP ratios along the northern transect were higher by the factor of 2 to 3 than their southern counterparts. The O2/Ar-based NCP rates were comparable to POC flux measured with floating traps deployed at the southern stations, but exceeded by a factor of 5-10 the trap POC fluxes obtained at the northern stations. A one-dimensional box model has been constructed to quantify the magnitude of oxygen primary production below the mixed layer. The results of this work will be integrated with measurements of 15-N2 uptake that are in progress, to constrain the potential contribution of N2 fixation

  14. A new method combining soil oxygen concentration measurements with the quantification of gross nitrogen turnover rates and associated formation of N2O and N2 emissions

    NASA Astrophysics Data System (ADS)

    Gütlein, Adrian; Dannenmann, Michael; Sörgel, Christoph; Meier, Rudi; Meyer, Astrid; Kiese, Ralf

    2014-05-01

    Climate change and the expansion of land use have led to significant changes in terrestrial ecosystems. These include changes in the biogeochemical cycle of nitrogen and therewith implications for biodiversity, water cycle and pedosphere-atmosphere exchange. To understand these impacts detailed research on nitrogen turnover and fluxes are conducted at various (semi-) natural and managed ecosystems in the Mt. Kilimanjaro region. In this context, we execute 15N tracing analyses on soil samples in our stable isotope laboratory including a new experimental setup. The soils were sampled from different forest ecosystems of Mt. Kilimanjaro varying in altitude (1600 - 4500 m) and will be analyzed for gross rates of ammonification and nitrification, gross rates of microbial inorganic N uptake as well as for the gaseous losses of ^15N2 and ^15N2O using ^15NH4+ and ^15NO3- tracing and pool dilution approaches. Since nitrogen turnover of nitrification and denitrification is dependent on soil oxygen concentrations we developed an incubation method which allows to adjust soil samples to different oxygen concentrations. For this purpose, soil is incubated in glass bottles with side tubes to ensure a constant gas flow over the whole incubation time. To adjust the oxygen levels in the laboratory experiment as close as possible to the natural conditions, we started to monitor soil oxygen concentrations with a FirestingO2 Sensor (Pyroscience) connected to a timer and a datalogger (MSR 145 IP 60 E3333) at a Mt. Kilimanjaro rainforest site. The equipment is complemented with soil temperature, moisture and pressure sensors (MSR 145 IP 60). A solar panel connected to an energy source guarantees a working time for over 2 years by a measuring frequency of 20 seconds each 30 minutes. The new laboratory incubation method together with in-situ oxygen concentration measurements in soils will facilitate laboratory incubations with realistic oxygen concentrations and thus will allow for a better

  15. A Study of the Relationship Between Utilization Patterns of Support Services and the Attrition and Retention Rates of Black College Students.

    ERIC Educational Resources Information Center

    Savitz, Fred R.; Walls, Adrienne

    1986-01-01

    Studied the effectiveness of the Support Service Staff at Saint Joseph's University by measuring the relationship between actual utilization of the services and perceived sensitivity of the personnel who are charged to provide them. The variables of rates of attrition and retention were used to determine the extent of utilization and its…

  16. Using Optical Oxygen Sensors and Injection Experiments to Determine in situ Microbial Rate Constants for Methane Oxidation and Heterotrophic Respiration in a Boreal Bog and Fen

    NASA Astrophysics Data System (ADS)

    Waldo, N.; Moorberg, C.; Waldrop, M. P.; Turetsky, M. R.; Neumann, R. B.

    2015-12-01

    Wetlands are the largest natural source of methane to the atmosphere, and play a key role in feedback cycles to climate change. In recognition of this, many researchers are developing process-based models of wetland methane emissions at various scales. In these models, the three key biogeochemical reactions are methane production, methane oxidation, and heterotrophic respiration, and they are modeled using Michaelis-Menten kinetics. The majority of Michaelis-Menten rate constants used in models are based on experiments involving slurries of peat incubated in vials. While these slurries provide a highly controlled setting, they are different from in situ conditions in multiple ways; notably they lack live plants and the centimeter-scale heterogeneities that exist in the field. To determine rate constants in a system more representative of in situ conditions, we extracted peat cores intact from a bog and fen located in the Bonanza Creek Experimental Forest near Fairbanks, Alaska and part of the Alaska Peatland Experiment (APEX) research program. Into those cores we injected water with varying concentrations of methane and oxygen at multiple depths. We used planar oxygen sensors installed on the peat cores to collect high resolution, two dimensional oxygen concentration data during the injections and used oxygen consumption rates under various conditions to calculate rate constants. Results were compared to a similar but smaller set of injection experiments conducted against planar oxygen sensors installed in the bog. Results will inform parametrization of microbial processes in wetland models, improving estimates of methane emissions both under current climate conditions and in the future.

  17. Adenosine triphosphate utilization rates and metabolic pool sizes in intact cells measured by transfer of 18O from water.

    PubMed Central

    Dawis, S M; Walseth, T F; Deeg, M A; Heyman, R A; Graeff, R M; Goldberg, N D

    1989-01-01

    The hydrolytic rates and metabolic pool sizes of ATP were determined in intact cells by monitoring the time courses of 18O incorporation from 18O-water into the gamma-phosphoryl of ATP and orthophosphate. To calculate the rate of ATP hydrolysis, a kinetic model is used to fit the time course of the 18O labeling. The size of the metabolic pool of ATP is calculated from the 18O distribution after isotopic equilibrium has been achieved. Metabolic pools have a binomial distribution of 18O whereas nonmetabolic pools exhibit negligible 18O labeling. The application and limitations of this approach are illustrated with data from isolated toad retinas and human platelets. At 22 degrees C, the time constant of ATP hydrolysis in the dark-adapted toad retina is about 30 s. Under these conditions, over 80% of the retinal ATP is involved in high-energy phosphate metabolism. It is calculated that when cGMP metabolic flux in the photoreceptors is maximally stimulated by light, it accounts for 10% of the ATP utilization by the entire retina. The time constant of ATP hydrolysis in human platelets at 37 degrees C is approximately 1 s, and 60% of the platelet ATP is involved in energy metabolism. PMID:2930826

  18. Sublethal effect of silver and chromium in the green mussel Perna viridis with reference to alterations in oxygen uptake, filtration rate and membrane bound ATPase system as biomarkers.

    PubMed

    Vijayavel, K; Gopalakrishnan, S; Balasubramanian, M P

    2007-10-01

    Perna viridis is an ideal animal for studying the impairment caused by the effects of heavy metals that are often detected in coastal areas. Preliminary bioassay tests revealed that the lethal (LC(100)), median lethal (LC(50)) and sublethal (LC(0)) concentration of silver and chromium to P. viridis were 6.5, 4.0, 2.0 mg l(-1) and 4.5, 2.5, 1.0 mg l(-1), respectively. Toxic effect of silver and chromium was evaluated in the green mussel P. viridis, with reference to oxygen consumption, filtration rate and ATPase system in laboratory experiments. These parameters were selected as the end point of sublethal stress. Oxygen consumption and filtration rates were calculated as a measure of decline in the dissolved oxygen level and algal concentration (feed) in the aquaria water, respectively. Silver and chromium affects both oxygen consumption and filtration rate significantly (P<0.01) at 96 h when compared to control. The activity of ATPases system in the gills, hepatopancreas, ovary and muscle of mussels were inhibited by silver and chromium indicating that metals exerted significant toxic effect. The inhibition of Na(+)K(+) ATPase, Ca(2+) ATPase and Mg(2+) ATPase in the mussels were significant (P<0.05) for silver and highly significant (P<0.01) for chromium, which indicates that chromium was more toxic to mussels when compared to silver. The assessment of oxygen consumption, filtration and ATPases system can thus be used as a valid biomarker in aquatic ecotoxicology studies. PMID:17585996

  19. Estimation of the Optimal Brachytherapy Utilization Rate in the Treatment of Gynecological Cancers and Comparison With Patterns of Care

    SciTech Connect

    Thompson, Stephen R.; Delaney, Geoff P.; Gabriel, Gabriel S.; Jacob, Susannah; Das, Prabir; Barton, Michael B.

    2013-02-01

    Purpose: We aimed to estimate the optimal proportion of all gynecological cancers that should be treated with brachytherapy (BT)-the optimal brachytherapy utilization rate (BTU)-to compare this with actual gynecological BTU and to assess the effects of nonmedical factors on access to BT. Methods and Materials: The previously constructed inter/multinational guideline-based peer-reviewed models of optimal BTU for cancers of the uterine cervix, uterine corpus, and vagina were combined to estimate optimal BTU for all gynecological cancers. The robustness of the model was tested by univariate and multivariate sensitivity analyses. The resulting model was applied to New South Wales (NSW), the United States, and Western Europe. Actual BTU was determined for NSW by a retrospective patterns-of-care study of BT; for Western Europe from published reports; and for the United States from Surveillance, Epidemiology, and End Results data. Differences between optimal and actual BTU were assessed. The effect of nonmedical factors on access to BT in NSW were analyzed. Results: Gynecological BTU was as follows: NSW 28% optimal (95% confidence interval [CI] 26%-33%) compared with 14% actual; United States 30% optimal (95% CI 26%-34%) and 10% actual; and Western Europe 27% optimal (95% CI 25%-32%) and 16% actual. On multivariate analysis, NSW patients were more likely to undergo gynecological BT if residing in Area Health Service equipped with BT (odds ratio 1.76, P=.008) and if residing in socioeconomically disadvantaged postcodes (odds ratio 1.12, P=.05), but remoteness of residence was not significant. Conclusions: Gynecological BT is underutilized in NSW, Western Europe, and the United States given evidence-based guidelines. Access to BT equipment in NSW was significantly associated with higher utilization rates. Causes of underutilization elsewhere were undetermined. Our model of optimal BTU can be used as a quality assurance tool, providing an evidence-based benchmark against

  20. Investigation of stability characteristics of cold-season convective precipitation events by utilizing the growth rate parameter

    NASA Astrophysics Data System (ADS)

    Melick, Christopher J.; Market, Patrick S.; Smith, Larry L.; Pettegrew, Brian P.; Becker, Amy E.; Lupo, Anthony R.

    2008-04-01

    The seldom utilized growth rate parameter (σ2), which predicts how rapidly a small-amplitude disturbance will grow in a conditional symmetrically unstable environment, was applied to study the stability characteristics of convective precipitation case studies across the central United States during the winter seasons of 2003-2004 and 2004-2005. The goals were to improve our understanding of how the environment becomes destabilized over a relatively short period of time, as well as to determine approximately where and when elevated thunderstorms are likely to develop. The comprehensive evaluation comprised a case study example and summary of statistics obtained by tabulations at the initiation site and spatial compositing of all case studies identified. The doubling time for the convection (the time required for a convective element to achieve twice its current depth) was found to be on the order of 1.3 h, which is consistent with the typical timescale for moist slantwise convection resulting from the release of conditional symmetric instability. The development of cold-season precipitation with lightning (i.e., thundersnow) and any associated banding was correctly and most accurately predicted from trends in plots of σ2 analyzed at the level at which the highest significant growth rates occurred. While this naturally varied from one event to the next, the average elevation tended to be close to 650 hPa. Furthermore, a term-by-term diagnosis of the mathematical expression for the growth rate was determined to be quite useful as another means of identifying the type of instability released within instances of wintertime convection. By calculating the individual contributions to the growth rate and observing whether a positive or negative response was obtained, the nature of the stability regime present was also ascertained. The inclusion of a set of non-thundering snowstorms helped to substantiate the assumption that atmospheres are less stable and more susceptible

  1. [Effects of nitrogen application rates on nitrogen uptake and utilization of direct-seeded cotton after wheat harvest].

    PubMed

    Zuang, Guo-wei; Yang, Chang-qin; Ni, Wan-chao; Liu, Rui-xian

    2016-01-01

    An experiment was carried out to study the effects of different nitrogen application rates (0, 60, 120, 150, 180 and 240 kg N · hm⁻²) on the nitrogen uptake, utilization and distribution of short season cotton cultivar (CCRI-50) which was directly seeded after wheat harvest. Results showed that nitrogen application increased the nitrogen uptake of cotton at different growth stages, with the highest increment at the peak flowering-boll opening stage. Nitrogen application changed the percentages of nitrogen uptake among different growth stages. The percentages of nitrogen uptake decreased from seedling to peak flowering stage, but increased from peak flowering to boll maturing stage. In addition, nitrogen application reduced the decreasing speed of nitrogen concentration in middle and upper fruiting branches at later growth stages. Direct-seeded cotton had nitrogen and biomass accumulation in the lower and middle reproductive branches. With the nitrogen application of 150-180 kg · hm⁻², the lint yield, NARE (nitrogen apparent recovery efficiency) and the economic coefficient of biomass and nitrogen were relatively higher, and the eigenvalues of dynamic model of nitrogen content and nitrogen accumulation were relatively coordinate. Excessively high nitrogen application (over 180 kg N · hm⁻²) decreased biomass and nitrogen amount of reproductive organ in lower and middle branches, narrow rise of yield, and lower nitrogen use efficiency. However, excessively low nitrogen application (lower than 150 kg N · hm⁻²) also resulted in lower economic coefficient of biomass and nitrogen and yield. These results suggested the optimum nitrogen application rate 150-180 kg N · hm⁻² for direct-seeded cotton after wheat harvest in lower reaches of Yangtze River. PMID:27228605

  2. Radiative power and electron cooling rates for oxygen in steady-state and transient plasmas at densities beyond the coronal limit

    SciTech Connect

    Keane, C.; Skinner, C.H.

    1986-01-01

    We have developed a time-dependent, collisional-radiative model to calculate radiative power and electron cooling rates for oxygen at intermediate densities (10/sup 16/ cm/sup -3/ less than or equal to n/sub e/ less than or equal to 10/sup 20/ cm/sup -3/) where the usual coronal approximation is not valid. Large differences from coronal values are predicted. The behavior of the steady-state radiative power loss coefficient, L/sub Z, is investigated as the electron density is increased. Generalized power loss coefficients applicable to transient plasmas are derived and applied to ionizing and recombining oxygen plasmas. Time-dependent effects are found to play a large role both in terms of the total radiated power and the net electron energy loss rate. 41 refs., 11 figs.

  3. The effect of oxygen flow rate and radio frequency plasma power on cubic ZnMgO ultraviolet sensors grown by plasma-enhanced molecular beam epitaxy

    SciTech Connect

    Casey Boutwell, R.; Wei Ming; Schoenfeld, Winston V.

    2013-07-15

    Cubic Zn{sub 1-x}Mg{sub x}O thin films were produced by Plasma-Enhanced Molecular Beam Epitaxy. Oxygen flow rate and applied Radio-Frequency (RF) plasma power were varied to investigate the impact on film growth and optoelectronic device performance. Solar-blind and visible-blind detectors were fabricated with metal-semiconductor-metal interdigitated Ni/Mg/Au contacts and responsivity is compared under different growth conditions. Increasing oxygen flow rate and RF plasma power increased Zn incorporation in the film, which leads to phase segregation at relatively high Zn/Mg ratio. Responsivity as high as 61 A/W was measured in phase-segregated ZnMgO visible-blind detectors.

  4. Effect of solvent on the rate constant for the radiative deactivation of singlet molecular oxygen (/sup 1/. delta. /sub g/O/sub 2/)

    SciTech Connect

    Scurlock, R.D.; Ogilby, P.R.

    1987-08-13

    Relative rate constants for the radiative deactivation (k/sub r/) of singlet molecular oxygen (/sup 3/Sigma/sub g//sup -/O/sub 2/ reverse arrow /sup 1/..delta../sub g/O/sub 2/) have been determined in 15 solvents. A substantial solvent effect is observed. Changes in the value of k/sub r/ can exceed a factor of 20. A reasonably good correlation exists between the solvent polarizability, defined as a function of the solvent refractive index, and the radiative rate constant. We suggest that our data support a model in which /sup 1/..delta../sub g/O/sub 2/ is perturbed through the formation of a discrete oxygen-solvent collision complex.

  5. The utility of the Dementia Severity Rating Scale in differentiating mild cognitive impairment and Alzheimer disease from controls.

    PubMed

    Mitchell, Joel C; Dick, Malcolm B; Wood, Amanda E; Tapp, Andre M; Ziegler, Raphael

    2015-01-01

    The current study investigated the utility of the Dementia Severity Rating Scale (DSRS) total score to identify individuals at the earliest stage of impairment (ie, mild cognitive impairment/MCI). In addition, the authors sought to investigate how well the measure correlates with an expanded battery of cognitive tests and other measures of functional abilities. Of the 320 participants included in this study, 85 were normal controls, 96 had single-domain or multiple-domain amnestic MCI, and 139 had possible or probable Alzheimer disease (AD). Each participant underwent a thorough cognitive, neurological, and physical examination. Results from this study indicated that the DSRS total scores differed significantly between the 3 groups (P<0.001) and accurately identified 81% of the control group, 60% of the MCI group, and 78% of the AD group in a post hoc discriminant analysis. When combined with a brief cognitive measure (ie, Consortium to Establish a Registry for Alzheimer's Disease Word List 5 min recall test), the DSRS accurately identified 98% of the control group, 76% of the MCI group, and 82% of the AD group. Implications for clinical practice and proposed areas of future research are discussed. PMID:25187220

  6. Impact of Medication-Assisted Treatment for Opioid Addiction on Medicaid Expenditures and Health Services Utilization Rates in Vermont.

    PubMed

    Mohlman, Mary Kate; Tanzman, Beth; Finison, Karl; Pinette, Melanie; Jones, Craig

    2016-08-01

    In the face of increasing rates of overdose deaths, escalating health care costs, and the tremendous social costs of opioid addiction, policy makers are asked to address the questions of whether and how to expand access to treatment services. In response to an upward trend in opioid abuse and adverse outcomes, Vermont is investing in statewide expansion of a medication-assisted therapy program delivered in a network of community practices and specialized treatment centers (Hub & Spoke Program). This study was conducted to test the rationale for these investments and to establish a pre-Hub & Spoke baseline for evaluating the additive impact of the program. Using a serial cross-sectional design from 2008 to 2013 to evaluate medical claims for Vermont Medicaid beneficiaries with opioid dependence or addiction (6158 in the intervention group, 2494 in the control group), this study assesses the treatment and medical service expenditures for those receiving medication-assisted treatment compared to those receiving substance abuse treatment without medication. Results suggest that medication-assisted therapy is associated with reduced general health care expenditures and utilization, such as inpatient hospital admissions and outpatient emergency department visits, for Medicaid beneficiaries with opioid addiction. For state Medicaid leaders facing similar decisions on approaches to opioid addiction, these results provide early support for expanding medication-assisted treatment services rather than relying only on psychosocial, abstinence, or detoxification interventions. PMID:27296656

  7. An exploration of an alternative rate structure as a means of integrating equity and efficiency in a municipally owned natural gas distribution utility

    SciTech Connect

    Lynch, D.A.

    1989-01-01

    After two decades of a somewhat golden age for gas utilities and regulators, the 1970's saw a changing energy market characterized by curtailments and allocations in the natural gas industry. The Natural Gas Policy Act of 1978 provided incentives for new supplies but at increased prices. During a period of rapidly calculating natural gas prices (1979-1984), municipal owned public utility operators were criticized for not meeting the needs of the poor and other deprived members of society. The thesis of this paper is that this criticism of operators of municipal owned natural gas utilities stemmed from the observer conceiving of the utility as a social agency of government. This paper investigates the background of the problem and public utilities' obligations because of their status as regulated monopolies. The municipal owned natural gas utility's responsibility in meeting the social functions of government are considered. This paper argues that such a utility should be viewed as a business not a societal agency. Use of a utility's rate structure for satisfying the dictates of a system of distributive justice is investigated. The attempts made by state and local governments (moratoriums on delinquent shutoffs, lifeline rates, etc.) have been ineffective and counter productive. The utility's duty to offer service to all who request it; without discrimination among people similarly situated; to the limit of its capacity is considered with consumers duty to pay just bills. Arguments show that the rate structure, not quantity delivered, is the crucial factor in assuring distributive justice. Pricing is viewed from a philosophical perspective also an economic perspective. The only need identified for equity and economic efficiency is in rate structures.

  8. Heterolytic cleavage of peroxide by a diferrous compound generates metal-based intermediates identical to those observed with reactions utilizing oxygen-atom-donor molecules.

    PubMed

    Rowe, Gerard T; Rybak-Akimova, Elena V; Caradonna, John P

    2008-01-01

    Under cryogenic stopped-flow conditions, addition of 2-methyl-1-phenylprop-2-yl hydroperoxide (MPPH) to the diiron(II) compound, [Fe(2)(H(2)Hbamb)(2)(NMeIm)(2)] (1; NMeIm=N-methylimidazole; H(4)HBamb: 2,3-bis(2-hydroxybenzamido)dimethylbutane) results in heterolytic peroxide O-O bond cleavage, forming a high-valent species, 2. The UV/Vis spectrum of 2 and its kinetic behavior suggest parallel reactivity to that seen in the reaction of 1 with oxygen-atom-donor (OAD) molecules, which has been reported previously. Like the interaction with OAD molecules, the reaction of 1 with MPPH proceeds through a three step process, assigned to oxygen-atom transfer to the iron center to form a high-valent intermediate (2), ligand rearrangement of the metal complex, and, finally, decay to a diferric mu-oxo compound. Careful examination of the order of the reaction with MPPH reveals saturation behavior. This, coupled with the anomalous non-Arrhenius behavior of the first step of the reaction, indicates that there is a preequilibrium peroxide binding step prior to O-O bond cleavage. At higher temperatures, the addition of the base, proton sponge, results in a marked decrease in the rate of O-O bond cleavage to form 2; this is assigned as a peroxide deprotonation effect, indicating that the presence of protons is an important factor in the heterolytic cleavage of peroxide. This phenomenon has been observed in other iron-containing enzymes, the catalytic cycles of which include peroxide O-O bond cleavage. PMID:18680115

  9. Quantitative measurements of regional glucose utilization and rate of valine incorporation into proteins by double-tracer autoradiography in the rat brain tumor model

    SciTech Connect

    Kirikae, M.; Diksic, M.; Yamamoto, Y.L.

    1989-02-01

    We examined the rate of glucose utilization and the rate of valine incorporation into proteins using 2-(/sup 18/F)fluoro-2-deoxyglucose and L-(1-14C)-valine in a rat brain tumor model by quantitative double-tracer autoradiography. We found that in the implanted tumor the rate of valine incorporation into proteins was about 22 times and the rate of glucose utilization was about 1.5 times that in the contralateral cortex. (In the ipsilateral cortex, the tumor had a profound effect on glucose utilization but no effect on the rate of valine incorporation into proteins.) Our findings suggest that it is more useful to measure protein synthesis than glucose utilization to assess the effectiveness of antitumor agents and their toxicity to normal brain tissue. We compared two methods to estimate the rate of valine incorporation: kinetic (quantitation done using an operational equation and the average brain rate coefficients) and washed slices (unbound labeled valine removed by washing brain slices in 10% trichloroacetic acid). The results were the same using either method. It would seem that the kinetic method can thus be used for quantitative measurement of protein synthesis in brain tumors and normal brain tissue using (/sup 11/C)-valine with positron emission tomography.

  10. Association between minor loading vein architecture and light- and CO2-saturated rates of photosynthetic oxygen evolution among Arabidopsis thaliana ecotypes from different latitudes

    PubMed Central

    Cohu, Christopher M.; Muller, Onno; Stewart, Jared J.; Demmig-Adams, Barbara; Adams, William W.

    2013-01-01

    Through microscopic analysis of veins and assessment of light- and CO2-saturated rates of photosynthetic oxygen evolution, we investigated the relationship between minor loading vein anatomy and photosynthesis of mature leaves in three ecotypes of Arabidopsis thaliana grown under four different combinations of temperature and photon flux density (PFD). All three ecotypes exhibited greater numbers and cross-sectional area of phloem cells as well as higher photosynthesis rates in response to higher PFD and especially lower temperature. The Swedish ecotype exhibited the strongest response to these conditions, the Italian ecotype the weakest response, and the Col-0 ecotype exhibited an intermediate response. Among all three ecotypes, strong linear relationships were found between light- and CO2-saturated rates of photosynthetic oxygen evolution and the number and area of either sieve elements or of companion and phloem parenchyma cells in foliar minor loading veins, with the Swedish ecotype showing the highest number of cells in minor loading veins (and largest minor veins) coupled with unprecedented high rates of photosynthesis. Linear, albeit less significant, relationships were also observed between number and cross-sectional area of tracheids per minor loading vein versus light- and CO2-saturated rates of photosynthetic oxygen evolution. We suggest that sugar distribution infrastructure in the phloem is co-regulated with other features that set the upper limit for photosynthesis. The apparent genetic differences among Arabidopsis ecotypes should allow for future identification of the gene(s) involved in augmenting sugar-loading and -transporting phloem cells and maximal rates of photosynthesis. PMID:23898338

  11. 78 FR 36768 - Battery Utility of Ohio, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-19

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Battery Utility of Ohio, LLC; Supplemental Notice That Initial Market-Based... above-referenced proceeding, of Battery Utility of Ohio, LLC's application for market-based...

  12. Evidence of Circadian Rhythm, Oxygen Regulation Capacity, Metabolic Repeatability and Positive Correlations between Forced and Spontaneous Maximal Metabolic Rates in Lake Sturgeon Acipenser fulvescens

    PubMed Central

    Svendsen, Jon C.; Genz, Janet; Anderson, W. Gary; Stol, Jennifer A.; Watkinson, Douglas A.; Enders, Eva C.

    2014-01-01

    Animal metabolic rate is variable and may be affected by endogenous and exogenous factors, but such relationships remain poorly understood in many primitive fishes, including members of the family Acipenseridae (sturgeons). Using juvenile lake sturgeon (Acipenser fulvescens), the objective of this study was to test four hypotheses: 1) A. fulvescens exhibits a circadian rhythm influencing metabolic rate and behaviour; 2) A. fulvescens has the capacity to regulate metabolic rate when exposed to environmental hypoxia; 3) measurements of forced maximum metabolic rate (MMRF) are repeatable in individual fish; and 4) MMRF correlates positively with spontaneous maximum metabolic rate (MMRS). Metabolic rates were measured using intermittent flow respirometry, and a standard chase protocol was employed to elicit MMRF. Trials lasting 24 h were used to measure standard metabolic rate (SMR) and MMRS. Repeatability and correlations between MMRF and MMRS were analyzed using residual body mass corrected values. Results revealed that A. fulvescens exhibit a circadian rhythm in metabolic rate, with metabolism peaking at dawn. SMR was unaffected by hypoxia (30% air saturation (O2sat)), demonstrating oxygen regulation. In contrast, MMRF was affected by hypoxia and decreased across the range from 100% O2sat to 70% O2sat. MMRF was repeatable in individual fish, and MMRF correlated positively with MMRS, but the relationships between MMRF and MMRS were only revealed in fish exposed to hypoxia or 24 h constant light (i.e. environmental stressor). Our study provides evidence that the physiology of A. fulvescens is influenced by a circadian rhythm and suggests that A. fulvescens is an oxygen regulator, like most teleost fish. Finally, metabolic repeatability and positive correlations between MMRF and MMRS support the conjecture that MMRF represents a measure of organism performance that could be a target of natural selection. PMID:24718688

  13. Comparison of synthetic oviductal fluid and G1/G2 medium under low-1 oxygen atmosphere on embryo production and pregnancy rates in Nelore (Bos indicus) cattle.

    PubMed

    Sanches, B V; Pontes, J H F; Basso, A C; Ferreira, C R; Perecin, F; Seneda, M M

    2013-02-01

    In this work, we evaluated whether embryo development and pregnancy rates would be affected by culturing bovine Bos indicus embryos in Synthetic Oviductal Fluid with amino acids (SOFaa) or G1/G2 sequential medium under a low-oxygen atmosphere. Using Ovum Pick Up, we obtained 1,538 oocytes, divided into G1/G2 (n = 783) and SOFaa (n = 755). No difference was observed for blastocyst development among the groups (27.8% ± 14.6 and 34.9% ± 20.0 for G1/G2 and SOFaa respectively, p > 0.05). Transferring the embryos (n = 450) from both groups to recipients resulted in similar pregnancy rates for the G1/G2 (38.4% n = 78/203) compared to the SOFaa (39.7% n = 98/247). Our findings confirm that Bos indicus embryos cultured in SOFaa and G1/G2 under low-oxygen atmosphere have similar in vitro (blastocyst rate) and in vivo (pregnancy rate) developmental capacity. However, embryos cultured in G1/G2 medium have higher cleavage than those cultured in SOFaa medium. PMID:22448771

  14. Comparison of time-tradeoff utilities and rating scale values of cancer patients and their relatives: evidence for a possible plateau relationship.

    PubMed

    O'Leary, J F; Fairclough, D L; Jankowski, M K; Weeks, J C

    1995-01-01

    Because they are easy to administer, rating scales are often used as proxies for utility measures. The authors investigated the relationship between time-tradeoff utilities and rating scale values in two populations: 124 cancer patients asked to evaluate their current states of health and 102 relatives and close friends of cancer patients asked to evaluate health-state scenarios. None of the models tested effectively described the relationship between individual patients' rating scale values and time-tradeoff utilities for their current states of health. In contrast, both a plateau and a power-function model explained the variability in the responses of the relatives reasonably well (R2 = 0.56 and R2 = 0.58, respectively). Given that many respondents who were unwilling to trade off any time assigned rating scale values of well below 100, a plateau model may represent the best approach to adjusting rating scale values for health-state scenarios when it is not feasible to elicit time-tradeoff utilities. PMID:7783573

  15. Ambulatory 24-hour cardiac oxygen consumption and blood pressure-heart rate variability: effects of nebivolol and valsartan alone and in combination.

    PubMed

    Izzo, Joseph L; Khan, Safi U; Saleem, Osman; Osmond, Peter J

    2015-07-01

    We compared an angiotensin receptor blocker (valsartan; VAL), a beta-blocker (nebivolol; NEB) and the combination of NEB/VAL with respect to 24-hour myocardial oxygen consumption (determined by 24-hour ambulatory heart rate-central systolic pressure product [ACRPP]) and its components. Subjects with hypertension (systolic blood pressure >140 or diastolic blood pressure >90; n = 26) were studied in a double-blinded, double-dummy, forced-titration, crossover design with 3 random-order experimental periods: VAL 320 mg, NEB 40 mg, and NEB/VAL 320/40 mg daily. After 4 weeks of each drug, ambulatory pulse wave analysis (MobilOGraph) was performed every 20 minutes for 24 hours. All three treatments resulted in nearly identical brachial and central systolic blood pressures. NEB alone or in combination with VAL resulted in lower ACRPP (by 11%-14%; P < .001 each) and heart rate (by 18%-20%; P < .001 each) compared with VAL, but stroke work (ACRPP per beat) was lower with VAL. Relative and adjusted variability (standard deviation and coefficient of variation) of heart rate were also lower with NEB and NEB/VAL than VAL. Results in African Americans, the majority subpopulation, were similar to those of the entire treatment group. We conclude that the rate-slowing effects of NEB cause ambulatory cardiac myocardial oxygen consumption to be lower with NEB monotherapy or NEB/VAL combination therapy than with VAL monotherapy. NEB/VAL is not superior to NEB alone in controlling heart rate, blood pressure, or ACRPP. Heart rate variability but not ACRPP variability is reduced by NEB or the combination NEB/VAL. There is no attenuation of beta-blocker-induced rate-slowing effects of in African Americans. PMID:26116459

  16. Oxygen Consumption by Red Wines. Part I: Consumption Rates, Relationship with Chemical Composition, and Role of SO₂.

    PubMed

    Ferreira, Vicente; Carrascon, Vanesa; Bueno, Mónica; Ugliano, Maurizio; Fernandez-Zurbano, Purificación

    2015-12-30

    Fifteen Spanish red wines extensively characterized in terms of SO2, color, antioxidant indexes, metals, and polyphenols were subjected to five consecutive sensor-controlled cycles of air saturation at 25 °C. Within each cycle, O2 consumption rates cannot be interpreted by simple kinetic models. Plots of cumulated consumed O2 made it possible to define a fast and highly wine-dependent initial O2 consumption rate and a second and less variable average O2 consumption rate which remains constant in saturations 2 to 5. Both rates have been satisfactorily modeled, and in both cases they were independent of Fe and SO2 and highly dependent on Cu levels. Average rates were also related to Mn, pH, Folin, protein precipitable proanthocyanidins (PPAs), and polyphenolic profile. Initial rates were strong and negatively correlated to SO2 consumption, indicating that such an initial rate is either controlled by an unknown antioxidant present in some wines or affected by a poor real availability of SO2. Remaining unreacted SO2 is proportional to initial combined SO2 and to final free acetaldehyde. PMID:26654524

  17. Treatment of a slaughterhouse wastewater: effect of internal recycle rate on chemical oxygen demand, total Kjeldahl nitrogen and total phosphorus removal.

    PubMed

    Fongsatitkul, P; Wareham, D G; Elefsiniotis, P; Charoensuk, P

    2011-12-01

    This study investigated the ability of an anaerobic/anoxic/oxic (A2/O) system to treat a slaughterhouse wastewater. The system employed two identical continuous-flow reactors (101 total liquid volume each) running in parallel with the main operational variable, being the internal recycle (IR) rate. The chemical oxygen demand (COD), total Kjeldahl nitrogen (TKN) and total phosphorus (TP) performance was evaluated as the IR flowrate was increased from a Q of 151d(-1) to 4Q at a system hydraulic retention time of 16 h and a solids retention time of 10 d. The COD:TKN and COD:TP ratios were 8.2:1 and 54:1, which supported both nitrogen and phosphorus removal. For all IR multiples of Q, the COD removal was in excess of 90%. The TKN removal showed a modest improvement (a 4-5% increase, depending on the dissolved oxygen (DO)) as the IR doubled from Q to 2Q, but no further increase was observed at the 4Q IR rate. The TP removal reached its optimum (around 85%-89% (again depending on the DO)) at the 2Q rate. PMID:22439562

  18. Changes of Nitrogen Transformation Rates and Related Functional Genes Abundance under Different Dissolved Oxygen Levels in sediments form an Urban River

    NASA Astrophysics Data System (ADS)

    Zhang, Y.

    2015-12-01

    In the nitrogen rich urban river sediments, we investigated the nitrogen transformation rates and nitrogen-cycling genes in response to different dissolved oxygen (DO) supply levels (saturation, DO > 8.00 mg L-1; aerobic, 2.50 mg L-1 rates (ammonium release, ammonia oxidation, nitrite oxidation, denitrification, and anammox) and their corresponding integrated amounts were solved by the least square analysis. Results showed that the total amount of ammonium oxidation, nitrite oxidation, denitrification, and anammox increased with the elevated dissolved oxygen levels, but the amount of ammonium release decreased inversely. The increasing DO level also raised the total amount of nitrogen loss (from 6.12 mg N to 35.44 mg N) and its proportion to ammonium liberated (from 12.96% to 99.84%), but the contributions of anammox to nitrogen loss in each incubation showed no significant difference (83.36% to 89.19%). The dissolved oxygen facilitated an exponential increasing of the anammox oxidizing archaea (AOA) and bacteria (AOB), and raised the denitrifiers (nirK and nirS gene) abundance by an order, but its influence on anammox (hzsB) was insignificant. Four quantitative response relationships between nitrogen transformation rates, nitrogen functional genes abundances, and nitrogen concentrations were established by stepwise linear regression analysis. These relationships confirmed that different nitrogen transformation processes were coupled at the molecular level (functional genes), especially for the coupling of ammonium oxidation and anammox.

  19. The Incremental Utility of Behavioral Rating Scales and a Structured Diagnostic Interview in the Assessment of Attention-Deficit/Hyperactivity Disorder

    ERIC Educational Resources Information Center

    Vaughn, Aaron J.; Hoza, Betsy

    2013-01-01

    The current study examined the incremental utility of rating scales, a structured diagnostic interview, and multiple informants in a comprehensive assessment of attention-deficit/hyperactivity disorder (ADHD). The sample included 185 children with ADHD (M[subscript age] = 9.22, SD = 0.95) and 82 children without ADHD (M[subscript age] = 9.24, SD =…

  20. [Utilization rate of fertilizer N and dynamic changes of soil NO3(-)-N in summer maize field in semi-humid area of Northwest China].

    PubMed

    Fan, Ya-ning; Li, Shi-qing; Li, Sheng-xiu

    2008-04-01

    A field experiment on manual loessial soil was conducted to study the dynamic changes of NO3(-)-N in soil profile, utilization rate of fertilizer N, and relationships between N application rate and soil residual N accumulation during the growth period of summer maize under different N application rates (0, 45, 90, 135, and 180 kg hm(-2)). The results showed that in the whole growth period of summer maize, the NO3(-)-N concentration in the soil profile was the highest in 0-20 cm layer, and increased with increasing N application rate. The NO3(-)-N concentration in 0-60 cm soil layer changed significantly, but no significant change was observed in 60-100 cm soil layer. In the growth season of summer maize, soil NO3(-)-N accumulation presented a fluctuated decreasing trend due to the N uptake by crop and the precipitation. The N utilization rate (NUR) increased with increasing N application rate when the application rate was less than 135 kg hm(-2), but tended to decrease when the application rate exceeded 135 kg hm(-2). With the increase of N application rate, the N agronomy efficiency (NAE) decreased but the N physiology efficiency (NPE) increased. There was a significant positive correlation between soil residual N accumulation and N application rate (R2 = 0.957**, n = 5). The grain yield under N application was significantly higher than that without N application (P <0.05), and there existed a significant positive correlation between grain yield and N application rate (R2 = 0.934**, n = 5). In our experiment, the optimal application rate of fertilizer N was 135 kg hm(-2), which could harmonize the relationship between economic benefits and environment. PMID:18593041

  1. Responses of Alnus glutinosa to anaerobic conditions--mechanisms and rate of oxygen flux into the roots.

    PubMed

    Dittert, K; Wötzel, J; Sattelmacher, B

    2006-03-01

    Upon exposure to waterlogged growing conditions two-year-old alder trees reduced total root mass. Roots were concentrated in the uppermost soil horizon, and only few coarse roots penetrated into deeper soil layers. Root porosity was only slightly affected and did not exceed 8 % in fine roots. Porosity of coarse roots was higher (27 %) but unaffected by growing conditions. The stem base area covered by lenticels increased strongly and so did the cross section diameter of the stem base. The latter showed a highly significant correlation with O (2) transport into the roots, measured by a Clark type oxygen electrode. Exposure of the lower 5 cm of the stem base, where lenticels were concentrated, to pure N (2) led to a cessation of O (2) transport, confirming that lenticels were the major site of air entry into the stem. In alder plants grown under waterlogged conditions, temperature had a pronounced effect on O (2) gas exchange of the root system. The temperature compensation point, i.e., the temperature where O (2) transport equals O (2) consumption by respiration, was 10.5 degrees C for the entire root system, when measured in a range of 0.15 - 0.20 mmol dissolved O (2) L (-1), which is typical for an open water surface equilibrated with air. O (2) net flow was inversely related to O (2) concentration in the rooting media, indicating that higher root and microbial respiration induced higher net fluxes of O (2) into the root system. With 0.04 mmol dissolved O (2) L (-1) nutrient solution, the temperature compensation point increased to 20 degrees C. Measurement of O (2) gradients in the rhizosphere of agar-embedded roots using O (2) microelectrodes showed a preference for O (2) release in the tip region of coarse roots. Increasing stem temperature over air temperature by 5 degrees C stimulated O (2) flux into the roots as suggested by the model of thermo-osmotic gas transport. However determination of stem and air temperature in a natural alder swamp in northern

  2. Modeling the Oxygen Consumption Rates in Pacific Salmon and Steelhead: An Assessment of Current Models and Practices

    SciTech Connect

    Trudel, Marc; Geist, David R.; Welch, David W.

    2004-03-01

    Bioenergetic models of fish have been used to study a large number of processes. Like most models, bioenergetic models require the estimation of numerous parameters. As a consequence, they have often relied on parameters borrowed from other species or values extrapolated from other life stages or size-classes. The magnitude of the biases associated with these practices remains largely unknown. The objective of this study was to determine whether or not metabolic rates could be extrapolated between closely related species and life stages. We focused on Pacific salmon Oncorhynchus spp. and steelhead O. mykiss, as the metabolic rates of these species have been well documented. Our analyses showed that models derived from closely related species did not accurately predict the metabolic rates of salmon, indicating that the practice of "species borrowing" should be avoided in assessing fish metabolic rates. Our work also showed that allometric equations of metabolic rates were not stable when measured over small size ranges and that biases could be introduced when these models are extrapolated to smaller or larger fish. In addition, we found that, except for steelhead, published models of Pacific salmon metabolic rate were inaccurate. Mean bias ranged from close to 0% to over 200% depending on size and water temperature, with about two-thirds of the bias values exceeding 20%. These biases could have large impacts on bioenergetic model predictions. Increased funding and scientific recognition of the need for additional basic research will be necessary to build more accurate bioenergetic models for Pacific salmon, especially models applied to the ocean phase of the life cycle.

  3. Hurricane exposure and county fetal death rates, utilization of a county environmental quality index for confounding control.

    EPA Science Inventory

    The effects of natural disasters on public health are a rising concern, with increasing severity of disaster events. Many disaster studies utilize county-level analysis, however most do not control for county level environmental factors. Hurricane exposure during pregnancy could ...

  4. The impact of cell-specific absorption properties on the correlation of electron transport rates measured by chlorophyll fluorescence and photosynthetic oxygen production in planktonic algae.

    PubMed

    Blache, Ulrich; Jakob, Torsten; Su, Wanwen; Wilhelm, Christian

    2011-08-01

    Photosynthesis-irradiance (P-E)-curves describe the photosynthetic performance of autotrophic organisms. From these P-E-curves the photosynthetic parameters α-slope, P(max), and E(k) can be deduced which are often used to characterize and to compare different organisms or organisms in acclimation to different environmental conditions. Particularly, for in situ-measurements of P-E curves of phytoplankton the analysis of variable chlorophyll fluorescence proved its potential as a sensitive and rapid method. By using Chlorella vulgaris (Trebouxiophyceae), Nannochloropsis salina (Eustigmatophyceae), Skeletonema costatum and Cyclotella meneghiniana (Bacillariophyceae), the present study investigated the influence of cellular bio-optical properties on the correlation of the photosynthetic parameters derived from fluorescence-based P-E-curves with photosynthetic parameters obtained from the measurement of oxygen evolution. It is demonstrated that small planktonic algae show a wide range of cellular absorptivity which was subject to species-specifity, growth stage and environmental conditions, e.g. nutrient limitation. This variability in bio-optical properties resulted in a great deviation of relative electron transport rates (rETRs) from oxygen-based photosynthesis rates. Thus, the photosynthetic parameters α-slope and P(max) derived from rETRs strongly depend on the specific cellular absorptivity and cannot be used to compare the photosynthetic performance of cells with different optical properties. However, it was shown that E(k) is independent of cellular absorptivity and could be used to compare samples with unknown optical properties. PMID:21571541

  5. Oxygen rocking aqueous batteries utilizing reversible topotactic oxygen insertion/extraction in iron-based perovskite oxides Ca1–xLaxFeO3−δ

    PubMed Central

    Hibino, Mitsuhiro; Kimura, Takeshi; Suga, Yosuke; Kudo, Tetsuichi; Mizuno, Noritaka

    2012-01-01

    Developments of large-scale energy storages with not only low cost and high safety but also abundant metals are significantly demanded. While lithium ion batteries are the most successful method, they cannot satisfy all conditions. Here we show the principle of novel lithium-free secondary oxygen rocking aqueous batteries, in which oxygen shuttles between the cathode and anode composed of iron-based perovskite-related oxides Ca0.5La0.5FeOz (2.5 ≤ z ≤ 2.75 and 2.75 ≤ z ≤ 3.0). Compound Ca0.5La0.5FeOz can undergo two kinds of reduction and reoxidation of Fe4+/Fe3+ and Fe3+/Fe2+, that are accompanied by reversible and repeatable topotactic oxygen extraction and reinsertion during discharge and charge processes. PMID:22924108

  6. Effects of pH, Temperature, Dissolved Oxygen, and Flow Rate on Phosphorus Release Processes at the Sediment and Water Interface in Storm Sewer

    PubMed Central

    Li, Haiyan; Li, Mingyi; Zhang, Xiaoran

    2013-01-01

    The effects of pH, temperature, dissolved oxygen (DO), and flow rate on the phosphorus (P) release processes at the sediment and water interface in rainwater pipes were investigated. The sampling was conducted in a residential storm sewer of North Li Shi Road in Xi Cheng District of Beijing on August 3, 2011. The release rate of P increased with the increase of pH from 8 to 10. High temperature is favorable for the release of P. The concentration of total phosphorus (TP) in the overlying water increased as the concentration of DO decreased. With the increase of flow rate from 0.7 m s−1 to 1.1 m s−1, the concentration of TP in the overlying water increased and then tends to be stable. Among all the factors examined in the present study, the flow rate is the primary influence factor on P release. The cumulative amount of P release increased with the process of pipeline runoff in the rainfall events with high intensities and shorter durations. Feasible measures such as best management practices and low-impact development can be conducted to control the P release on urban sediments by slowing down the flow rate. PMID:24349823

  7. Effect of Cooling Rate and Oxygen Fugacity on the Crystallization of the Queen Alexandra Range 94201 Martian Melt Composition

    NASA Technical Reports Server (NTRS)

    Koizumi, E.; Mikouchi, T.; McKay, G.; Schwandt, C.; Monkawa, A.; Miyamoto, M.

    2002-01-01

    Although many basaltic shergottites have been recently found in north African deserts, QUE94201 basaltic shergottite (QUE) is still important because of its particular mineralogical and petrological features. This meteorite is thought to represent its parent melt composition [1 -3] and to crystallize under most reduced condition in this group [1,4]. We performed experimental study by using the synthetic glass that has the same composition as the bulk of QUE. After homogenization for 48 hours at 1300 C, isothermal and cooling experiments were done under various conditions (e.g. temperature, cooling rates, and redox states). Our goals are (1) to verify that QUE really represents its parent melt composition, (2) to estimate a cooling rate of this meteorite, (3) to clarify the crystallization sequences of present minerals, and (4) to verity that this meteorite really crystallized under reduced condition.

  8. Revision of the 15N(p, γ)16O reaction rate and oxygen abundance in H-burning zones

    NASA Astrophysics Data System (ADS)

    Caciolli, A.; Mazzocchi, C.; Capogrosso, V.; Bemmerer, D.; Broggini, C.; Corvisiero, P.; Costantini, H.; Elekes, Z.; Formicola, A.; Fülöp, Zs.; Gervino, G.; Guglielmetti, A.; Gustavino, C.; Gyürky, Gy.; Imbriani, G.; Junker, M.; Lemut, A.; Marta, M.; Menegazzo, R.; Palmerini, S.; Prati, P.; Roca, V.; Rolfs, C.; Rossi Alvarez, C.; Somorjai, E.; Straniero, O.; Strieder, F.; Terrasi, F.; Trautvetter, H. P.; Vomiero, A.

    2011-09-01

    Context. The NO cycle takes place in the deepest layer of a H-burning core or shell, when the temperature exceeds T ≃ 30 × 106 K. The O depletion observed in some globular cluster giant stars, always associated with a Na enhancement, may be due to either a deep mixing during the red giant branch (RGB) phase of the star or to the pollution of the primordial gas by an early population of massive asymptotic giant branch (AGB) stars, whose chemical composition was modified by the hot bottom burning. In both cases, the NO cycle is responsible for the O depletion. Aims: The activation of this cycle depends on the rate of the 15N(p, γ)16O reaction. A precise evaluation of this reaction rate at temperatures as low as experienced in H-burning zones in stellar interiors is mandatory to understand the observed O abundances. Methods: We present a new measurement of the 15N(p, γ)16O reaction performed at LUNA covering for the first time the center of mass energy range 70-370 keV, which corresponds to stellar temperatures between 65 × 106 K and 780 × 106 K. This range includes the 15N(p, γ)16O Gamow-peak energy of explosive H-burning taking place in the external layer of a nova and the one of the hot bottom burning (HBB) nucleosynthesis occurring in massive AGB stars. Results: With the present data, we are also able to confirm the result of the previous R-matrix extrapolation. In particular, in the temperature range of astrophysical interest, the new rate is about a factor of 2 smaller than reported in the widely adopted compilation of reaction rates (NACRE or CF88) and the uncertainty is now reduced down to the 10% level.

  9. Operational Considerations for Oxygen Flammability Risks: Concentrated Oxygen Diffusion and Permeation Behaviors

    NASA Technical Reports Server (NTRS)

    Harper, Susana; Smith, Sarah; Juarez, Alfredo; Hirsch, David

    2010-01-01

    Increased human spaceflight operations utilize oxygen concentrations that are frequently varied with use of concentrations up to 100 percent oxygen. Even after exiting a higher percentage oxygen environment, high oxygen concentrations can still be maintained due to material saturation and oxygen entrapment between barrier materials. This paper examines the material flammability concerns that arise from changing oxygen environments during spaceflight operations. We examine the time required for common spacecraft and spacesuit materials exposed to oxygen to return to reduced ignitability and flammability once removed from the increased concentration. Various common spacecraft materials were considered: spacecraft cabin environment foams, Extra Vehicular Mobility Unit materials and foams, Advanced Crew Escape Suit materials, and other materials of interest such as Cotton, Nomex^ HT90-40, and Tiburon Surgical Drape. This paper presents calculated diffusion coefficients derived from experimentally obtained oxygen transmission rates for the tested materials and the analytically derived times necessary for reduced flammability to be achieved based on NASA flammability criteria. Oxygen material saturation and entrapment scenarios are examined. Experimental verification data on oxygen diffusion in saturation scenarios are also presented and discussed. We examine how to use obtained data to address flammability concerns during operational planning to reduce the likelihood of fires while improving efficiency for procedures.

  10. In Situ Resource Utilization (ISRU) on the Moon: Moessbauer Spectroscopy as a Process Monitor for Oxygen Production. Results from a Field Test on Mauna Kea Volcano, Hawaii

    NASA Technical Reports Server (NTRS)

    Morris, R.V.; Schroder, C.; Graff, T.G.; Sanders, G.B.; Lee, K.A.; Simon, T.M.; Larson, W.E.; Quinn, J.W.; Clark, L.D.; Caruso, J.J.

    2009-01-01

    Essential consumables like oxygen must to be produced from materials on the lunar surface to enable a sustained, long-term presence of humans on the Moon. The Outpost Precursor for ISRU and Modular Architecture (OPTIMA) field test on Mauna Kea, Hawaii, facilitated by the Pacific International Space Center for Exploration Systems (PISCES) of the University of Hawaii at Hilo, was designed to test the implementation of three hardware concepts to extract oxygen from the lunar regolith: Precursor ISRU Lunar Oxygen Testbed (PILOT) developed by Lockheed Martin in Littleton, CO; Regolith & Environmental Science and Oxygen & Lunar Volatiles Extraction (RESOLVE) developed at the NASA Kennedy Space Center in Cape Canaveral, FL; and ROxygen developed at the NASA Johnson Space Center in Houston, TX. The three concepts differ in design, but all rely on the same general principle: hydrogen reduction of metal cations (primarily Fe2+) bonded to oxygen to metal (e.g., Fe0) with the production of water. The hydrogen source is residual hydrogen in the fuel tanks of lunar landers. Electrolysis of the water produces oxygen and hydrogen (which is recycled). We used the miniaturized M ssbauer spectrometer MIMOS II to quantify the yield of this process on the basis of the quantity of Fe0 produced. Iron M ssbauer spectroscopy identifies iron-bearing phases, determines iron oxidation states, and quantifies the distribution of iron between mineral phases and oxidation states. The oxygen yield can be calculated by quantitative measurements of the distribution of Fe among oxidation states in the regolith before and after hydrogen reduction. A M ssbauer spectrometer can also be used as a prospecting tool to select the optimum feedstock for the oxygen production plants (e.g., high total Fe content and easily reduced phases). As a demonstration, a MIMOS II backscatter spectrometer (SPESI, Germany) was mounted on the Cratos rover (NASA Glenn Research Center in Cleveland, OH), which is one of

  11. ENHANCED GROWTH RATE AND SILANE UTILIZATION IN AMORPHOUS SILICON AND NANOCRYSTALLINE-SILICON SOLAR CELL DEPOSITION VIA GAS PHASE ADDITIVES

    SciTech Connect

    Ridgeway, R G; Hegedus, S S; Podraza, N J

    2012-08-31

    Air Products set out to investigate the impact of additives on the deposition rate of both CSi and Si-H films. One criterion for additives was that they could be used in conventional PECVD processing, which would require sufficient vapor pressure to deliver material to the process chamber at the required flow rates. The flow rate required would depend on the size of the substrate onto which silicon films were being deposited, potentially ranging from 200 mm diameter wafers to the 5.7 m2 glass substrates used in GEN 8.5 flat-panel display tools. In choosing higher-order silanes, both disilane and trisilane had sufficient vapor pressure to withdraw gas at the required flow rates of up to 120 sccm. This report presents results obtained from testing at Air Products electronic technology laboratories, located in Allentown, PA, which focused on developing processes on a commercial IC reactor using silane and mixtures of silane plus additives. These processes were deployed to compare deposition rates and film properties with and without additives, with a goal of maximizing the deposition rate while maintaining or improving film properties.

  12. Influence of the formation- and passivation rate of boron-oxygen defects for mitigating carrier-induced degradation in silicon within a hydrogen-based model

    NASA Astrophysics Data System (ADS)

    Hallam, Brett; Abbott, Malcolm; Nampalli, Nitin; Hamer, Phill; Wenham, Stuart

    2016-02-01

    A three-state model is used to explore the influence of defect formation- and passivation rates of carrier-induced degradation related to boron-oxygen complexes in boron-doped p-type silicon solar cells within a hydrogen-based model. The model highlights that the inability to effectively mitigate carrier-induced degradation at elevated temperatures in previous studies is due to the limited availability of defects for hydrogen passivation, rather than being limited by the defect passivation rate. An acceleration of the defect formation rate is also observed to increase both the effectiveness and speed of carrier-induced degradation mitigation, whereas increases in the passivation rate do not lead to a substantial acceleration of the hydrogen passivation process. For high-throughput mitigation of such carrier-induced degradation on finished solar cell devices, two key factors were found to be required, high-injection conditions (such as by using high intensity illumination) to enable an acceleration of defect formation whilst simultaneously enabling a rapid passivation of the formed defects, and a high temperature to accelerate both defect formation and defect passivation whilst still ensuring an effective mitigation of carrier-induced degradation.

  13. Experimental Rate Study of Vitrinite Maturation as a Function of Temperature, Time, Starting Material, Aqueous Fluid Pressure, and Oxygen Fugacity: Corroboration of Prior Work

    NASA Astrophysics Data System (ADS)

    Ernst, W. G.; Mählmann, R. F.

    2002-05-01

    Kinetic studies were performed on disaggregated samples of gymnosperm and angiosperm huminite at 2.0 kbar aqueous fluid pressure and oxygen fugacities defined by hematite-magnetite and magnetite + quartz-fayalite solid buffers. Individual experiments lasted from 5-204 days. The rate of vitrinite reflectance (VR) increase was evaluated at 200, 250, 300, and 400oC isotherms; experimentally determined, approximately steady-state values for the mean percentage Rmax are 0.54, 0.74, 1.10, and 2.25, respectively. The overall activation energy governing the kinetics of several devolatilization reactions responsible for increase in VR measured in our experiments is 21.8+/- 0.3 kJ/mol. Combined with earlier rate studies conducted by Dalla Torre et al. (1997), we conclude that the rate of vitrinite maturation is unaffected by oxidation state, "wet" versus "dry" conditions, and the nature of the starting lignitic material. To a small extent, elevated lithostatic pressure retards the rate of increase in VR. These new run data demonstrate that VR is chiefly a function of temperature and time. In support of most earlier field, theoretical, and laboratory studies, our research indicates that, for all but geologically insignificant times intervals, vitrinite reflectance is an appropriate proxy for host-rock burial temperature.

  14. Enforcing Quality Metrics over Equipment Utilization Rates as Means to Reduce Centers for Medicare and Medicaid Services Imaging Costs and Improve Quality of Care

    PubMed Central

    Sura, Amit; Ho, Alexander

    2011-01-01

    Radiology has been the focus of efforts to reduce inefficiencies while attempting to lower medical costs. The 2010 Medicare Physician Fee Schedule has reduced Centers for Medicare and Medicaid Services’ (CMS) reimbursements related to the technical component of imaging services. By increasing the utilization rate, the cost of equipment spreads over more studies, thus lowering the payments per procedure. Is it beneficial for CMS to focus on equipment utilization as a cost-cutting measure? Can greater financial and quality of care rewards be made by improving metrics like appropriateness criteria and pre-authorization? On examining quality metrics, such as appropriateness criteria and pre-authorization, promising results have ensued. The development and enforcement of appropriateness criteria lowers overutilization of studies without requiring unattainable fixed rates. Pre-authorization educates ordering physicians as to when imaging is indicated. PMID:21966625

  15. Effects of exercise-induced muscle damage on resting metabolic rate, sub-maximal running and post-exercise oxygen consumption.

    PubMed

    Burt, Dean Gareth; Lamb, Kevin; Nicholas, Ceri; Twist, Craig

    2014-01-01

    Exercise-induced muscle damage (EIMD), described as the acute weakness of the musculature after unaccustomed eccentric exercise, increases oxidative metabolism at rest and during endurance exercise. However, it is not known whether oxygen uptake during recovery from endurance exercise is increased when experiencing symptoms of EIMD. Therefore, the purpose of this study was to investigate the effects of EIMD on physiological and metabolic responses before, during and after sub-maximal running. After a 12 h fast, eight healthy male participants completed baseline measurements comprising resting metabolic rate (RMR), indirect markers of EIMD, 10 min of sub-maximal running and 30 min of recovery to ascertain excess post-exercise oxygen consumption (EPOC). Measurements were then repeated at 24 and 48 h after 100 Smith-machine squats. Data analysis revealed significant (P<0.05) increases in muscle soreness and creatine kinase (CK) and decreases in peak knee extensor torque at 24 and 48 h after squatting exercise. Moreover, RMR, physiological, metabolic and perceptual responses during sub-maximal running and EPOC were increased in the two days after squatting exercise (P<0.05). It is suggested that the elevated RMR was a consequence of a raised energy requirement for the degradation and resynthesis of damaged muscle fibres. The increased oxygen demand during sub-maximal running after muscle damage was responsible for the increase in EPOC. Individuals engaging in unaccustomed resistance exercise that results in muscle damage should be mindful of the increases in resting energy expenditure and increased metabolic demand to exercise in the days that follow. PMID:23566074

  16. Implications for oxygen, nutrient fluxes and denitrification rates during the early stage of sediment colonisation by the polychaete Nereis spp. in four estuaries

    NASA Astrophysics Data System (ADS)

    Nizzoli, Daniele; Bartoli, Marco; Cooper, Martin; Welsh, David T.; Underwood, Graham J. C.; Viaroli, Pierluigi

    2007-10-01

    In this work, bioturbation effects by the polychaete Nereis spp. on oxygen demand, denitrification and solute fluxes in four European coastal areas (Goro lagoon in Italy, Tagus estuary in Portugal, Colne estuary in England and Tjärnö bay in Sweden) are compared. The studied areas are very heterogeneous with respect to tidal regimes, primary producers communities, sediment composition and organic matter content and nutrient concentrations in the water column. At each site, with the same methodological approach, undisturbed sediment cores and cores with different numbers of polychaetes added were incubated in the dark. Oxygen, inorganic nutrients (NH 4+, NO 3-, Dissolved Reactive Silica-SiO 2 and Soluble Reactive Phosphorous-SRP) fluxes and coupled-uncoupled denitrification rates were quantified on the same set of cores. Nereis bioturbation had a considerable effect on biogeochemical processes and, at all sites, resulted in an immediate stimulation (from 1.5- to 4-fold higher) of oxygen and ammonium fluxes between the sediment and the water column; on the contrary bioturbation had site specific effects on reactive silica and phosphorus fluxes. Bioturbation also stimulated denitrification of water column nitrate ( Dw, from 1.3 to 3 times higher than in control sediments); this process removed a major fraction (>50%) of the nitrogen lost through denitrification. Overall, the strong relationship between benthic macrofauna activity and sediment biogeochemistry is confirmed by this study. Comparison of the relative stimulation of processes in different geographical areas reveals that the degree by which processes and fluxes (intensity and direction) are affected are site specific and influenced by initial macrofauna densities and sediment and water chemistry.

  17. Estimation of the regional cerebral metabolic rate of oxygen consumption with proton detected 17O MRI during precision 17O2 inhalation in swine

    PubMed Central

    Mellon, Eric A.; Beesam, R. Shashank; Baumgardner, James E.; Borthakur, Arijitt; Witschey, Walter R.; Reddy, Ravinder

    2009-01-01

    Despite the importance of metabolic disturbances in many diseases, there are currently no clinically used methods for the detection of oxidative metabolism in vivo. To address this deficiency, 17O MRI techniques are scaled from small animals to swine as a large animal model of human inhalation and circulation. The hemispheric cerebral metabolic rate of oxygen consumption (CMRO2) is estimated in swine by detection of metabolically produced H217O by rapid T1ρ-weighted proton magnetic resonance imaging on a 1.5 Tesla clinical scanner. The 17O is delivered as oxygen gas by a custom, minimal-loss, precision-delivery breathing circuit and converted to H217O by oxidative metabolism. A model for gas arterial input is presented for the deeply breathing large animal. The arterial input function for recirculation of metabolic water is measured by arterial blood sampling and high field 17O spectroscopy. It is found that minimal metabolic water “wash-in” occurs before 60 seconds. A high temporal resolution pulse sequence is employed to measure CMRO2 during those 60 seconds after delivery begins. Only about one tidal volume of 17O enriched oxygen gas is used per measurement. Proton measurements of signal change due to metabolically produced water are correlated with 17O in vivo spectroscopy. Using these techniques, the hemispheric CMRO2 in swine is estimated to be 1.23 ± 0.26 μmol/g/min, consistent with existing literature values. All of the technology used to perform these CMRO2 estimates can easily be adapted to clinical MR scanners, and it is hoped that this work will lead to future studies of human disease. PMID:19428508

  18. Comparing the effectiveness of heat rate improvements in different coal-fired power plants utilizing carbon dioxide capture

    NASA Astrophysics Data System (ADS)

    Walsh, Martin Jeremy

    New Congressional legislation may soon require coal-fired power generators to pay for their CO2 emissions and capture a minimum level of their CO2 output. Aminebased CO2 capture systems offer plants the most technically proven and commercially feasible option for CO2 capture at this time. However, these systems require a large amount of heat and power to operate. As a result, amine-based CO2 capture systems significantly reduce the net power of any units in which they are installed. The Energy Research Center has compiled a list of heat rate improvements that plant operators may implement before installing a CO2 capture system. The goal of these improvements is to upgrade the performance of existing units and partially offset the negative effects of adding a CO2 capture system. Analyses were performed in Aspen Plus to determine the effectiveness of these heat rate improvements in preserving the net power and net unit heat rate (NUHR) of four different power generator units. For the units firing high-moisture sub-bituminous coal, the heat rate improvements reduced NUHR by an average of 13.69% across a CO 2 capture level range of 50% to 90%. For the units firing bituminous coal across the same CO2 capture range, the heat rate improvements reduced NUHR by an average of 12.30%. Regardless of the units' coal or steam turbine cycle type, the heat rate improvements preserved 9.7% to 11.0% of each unit's net power across the same CO2 capture range. In general, the heat rate improvements were found to be most effective in improving the performance of units firing high-moisture sub-bituminous. The effect of the CO2 capture system on these units and the reasons for the improvements' greater effectiveness in them are described in this thesis.

  19. The OXYGEN-15(ALPHA, GAMMA)NEON-19 Reaction Rate and the Rapid-Proton Capture Process

    NASA Astrophysics Data System (ADS)

    Magnus, Paul Vogt

    The energetics and the rates of the various nuclear reaction chains active in stars play a critical role in the stars' evolution and in the isotopic abundances resulting from this nucleosynthesis. One can therefore gain information about the structure and evolution of stars by examining these nuclear reaction chains and the resulting elemental and isotopic abundances. The abundances of a number of isotopes (e.g., 13C and ^ {15}N) point to the importance of explosive hydrogen burning which takes place on time scales which are short compared to the relevant beta-decay lifetimes. Explosive hydrogen burning is expected to occur at high temperatures (rm T>2times10^8K) in many astrophysical environments such as super-massive stars, accreting neutron stars, red giants with neutron star cores, novae, and supernovae. In these environments it is usually assumed that hydrogen burning occurs via the Hot-CNO (HCNO) cycle which is responsible for the observed abundance of 15N. At sufficiently high temperatures, however, the ^ {15}O(alpha,gamma)^{19 }Ne reaction can break the HCNO cycle and initiate a reaction chain called the rapid-proton capture (rp) process. The rp process transforms CNO nuclei to heavier nuclei (up to iron and nickel) by a chain of successive proton captures and beta decays. Hydrogen and helium-burning reactions, including the 15O( alpha,gamma)19Ne breakout reaction and the subsequent rp process, are thought to be the energy source for novae on the surface of accreting neutron stars and are possibly responsible for the unusual concentrations of heavy elements recently observed in novae. At astrophysically important temperatures, the 15O(alpha,gamma) 19Ne reaction rate is determined by the properties of several resonances just above the alpha-particle threshold in 19 Ne (Ecm<1.2 MeV). This thesis involves a series of experiments which determine the reaction rate for the 15O(alpha,gamma)^ {19}Ne reaction by measuring the properties of these resonances. The ^{15

  20. FUNDAMENTAL AREAS OF PHENOMENOLOGY (INCLUDING APPLICATIONS): Silicon Dioxide Coating Deposited by PDPs on PET Films and Influence on Oxygen Transmission Rate

    NASA Astrophysics Data System (ADS)

    Sun, Yun-Jin; Fu, Ya-Bo; Chen, Qiang; Zhang, Chun-Mei; Sang, Li-Jun; Zhang, Yue-Fei

    2008-05-01

    A silicon dioxide film is deposited on the polyethyleneterephtalate (PET) by a penning discharge plasma source at ambient temperature in a high vacuum chamber. Hexamethyldisiloxane and oxygen are adopted as precursor and reactive reagent to grow a nano-scale silicon dioxide layer on polymer surfaces. For the chemical structure analysis x-ray photoelectron spectroscopy is performed to demonstrate the content of Si, O and C elements. It is noticed that a higher silicon concentration is contained if Ar plasma is used for pretreatment. X-ray diffraction analysis shows that a micro-crystal silicon dioxide is formed by peak patterns at 25.84° and 21.8°. The barrier properties examined by oxygen transmission rate show that the permeation parameter of the 12-μm-thick PET film drastically decreases from 135cc/m2 per day for the control one to 0.713cc/m2 per day for the as-deposited one after Ar plasma treatment. The surface morphology related to the barrier properties of SiOx-coated polymers os also investigated by scanning electron microscopy and atomic force microscopy.

  1. Development of a new oxygen consumption rate assay in cultures of Acanthamoeba (Protozoa: Lobosea) and its application to evaluate viability and amoebicidal activity in vitro.

    PubMed

    Heredero-Bermejo, I; Criado-Fornelio, A; Soliveri, J; Díaz-Martín, J A; Matilla-Fuentes, J; Sánchez-Arias, J A; Copa-Patiño, J L; Pérez-Serrano, J

    2015-08-01

    A new fluorometric method has been developed for measuring the oxygen consumption rate (OCR) of Acanthamoeba cultures in microplates and for screening molecules with amoebicidal activity against this microorganism. The use of a biofunctional matrix (containing an oxygen-sensitive fluorogenic probe) attached to the microplate wells allowed continuous measurement of OCR in the medium, hence assessment of amoebic growth. The new OCR method applied to cell viability yielded a linear relationship and monitoring was much quicker than with indirect viability assays previously used. In addition, two drugs were tested in a cytotoxicity assay monitored by the new OCR viability test. With this procedure, the standard amoebicidal drug chlorhexidine digluconate showed an IC50 of 3.53 + 1.3 mg/l against Acanthamoeba polyphaga and 3.19 + 1.2 mg/l against Acanthamoeba castellanii, whereas a cationic dendrimer [G1Si(NMe3+)4] showed an IC50 of 6.42 + 1.3 mg/l against A. polyphaga. These data agree with previous studies conducted in our laboratory. Therefore, the new OCR method has proven powerful and quick for amoebicidal drug screening and is likely to be applied in biochemical studies concerning protozoa respiration and metabolism. PMID:25956947

  2. The Clinical Utility of the Behavior Rating Inventory of Executive Function (BRIEF) in the Diagnosis of ADHD

    ERIC Educational Resources Information Center

    McCandless, Stephen; O'Laughlin, Liz

    2007-01-01

    Objective: Current theories hypothesize that deficits in executive functioning (EF) are responsible for the symptoms of ADHD and that specific patterns of EF deficits may be associated with different subtypes of ADHD. The present study evaluates the validity and clinical usefulness of the Behavior Rating Inventory of Executive Function, a behavior…

  3. Recent trends in hormone therapy utilization and breast cancer incidence rates in the high incidence population of Marin County, California

    PubMed Central

    2010-01-01

    Background Recent declines in invasive breast cancer have been reported in the US, with many studies linking these declines to reductions in the use of combination estrogen/progestin hormone therapy (EPHT). We evaluated the changing use of postmenopausal hormone therapy, mammography screening rates, and the decline in breast cancer incidence specifically for Marin County, California, a population with historically elevated breast cancer incidence rates. Methods The Marin Women's Study (MWS) is a community-based, prospective cohort study launched in 2006 to monitor changes in breast cancer, breast density, and personal and biologic risk factors among women living in Marin County. The MWS enrolled 1,833 women following routine screening mammography between October 2006 and July 2007. Participants completed a self-administered questionnaire that included items regarding historical hormone therapy regimen (estrogen only, progesterone only, EPHT), age of first and last use, total years of use, and reason(s) for stopping, as well as information regarding complementary hormone use. Questionnaire items were analyzed for 1,083 non-Hispanic white participants ages 50 and over. Breast cancer incidence rates were assessed overall and by tumor histology and estrogen receptor (ER) status for the years 1990-2007 using data from the Northern California Surveillance, Epidemiology and End Results (SEER) cancer registry. Results Prevalence of EPHT use among non-Hispanic white women ages 50 and over declined sharply from 21.2% in 1998 to 6.7% by 2006-07. Estrogen only use declined from 26.9% in 1998 to 22.4% by 2006-07. Invasive breast cancer incidence rates declined 33.4% between 2001 and 2004, with drops most pronounced for ER+ cancers. These rate reductions corresponded to declines of about 50 cases per year, consistent with population attributable fraction estimates for EPHT-related breast cancer. Self-reported screening mammography rates did not change during this period. Use of

  4. Solid state oxygen sensor

    DOEpatents

    Garzon, Fernando H.; Brosha, Eric L.

    1997-01-01

    A potentiometric oxygen sensor is formed having a logarithmic response to a differential oxygen concentration while operating as a Nernstian-type sensor. Very thin films of mixed conducting oxide materials form electrode services while permitting diffusional oxygen access to the interface between the zirconia electrolyte and the electrode. Diffusion of oxygen through the mixed oxide is not rate-limiting. Metal electrodes are not used so that morphological changes in the electrode structure do not occur during extended operation at elevated temperatures.

  5. Slower recovery rate of muscle oxygenation after sprint exercise in long-distance runners compared with that in sprinters and healthy controls.

    PubMed

    Nagasawa, Takeshi

    2013-12-01

    The purpose of this study was to examine whether differences in aerobic capacity and training status influence muscle reoxygenation after sprint exercise. We hypothesized that the muscle reoxygenation rate after sprint exercise is slower in long-distance runners with a high aerobic capacity. Five male long-distance runners, 5 male sprinters, and 6 healthy male controls performed a 30-second sprint exercise on a cycle ergometer. Oxygen saturation in muscle tissue (StO2) in the vastus lateralis muscles was measured by near-infrared spectroscopy. The muscle reoxygenation rate after the exercise was evaluated at half the time required for StO2 recovery (T1/2 StO2). Aerobic capacity was evaluated by measuring maximal oxygen consumption (V[Combining Dot Above]O2max). The T1/2 StO2 in the long-distance runners (25.0 ± 4.5 seconds) was significantly longer than that in the controls (15.9 ± 1.6 seconds; p < 0.01) and in the sprinters (18.0 ± 4.6 seconds; p < 0.05). In all the subjects (long-distance runners, sprinters, and controls), the T1/2 StO2 had a significant positive correlation with the V[Combining Dot Above]O2max (r = 0.75; p < 0.01) and was longer in subjects with a higher V[Combining Dot Above]O2max. These results suggest that reoxygenation after sprint exercise is influenced by aerobic capacity and training status, and that the subjects with a higher aerobic capacity have delayed muscle reoxygenation after sprint exercise. PMID:23604001

  6. The Online Morphology Control and Dynamic Studies on Improving Vitamin B12 Production by Pseudomonas denitrificans with Online Capacitance and Specific Oxygen Consumption Rate.

    PubMed

    Wang, Ze-Jian; Shi, Hui-Lin; Wang, Ping

    2016-07-01

    The relationship between the morphological character of Pseudomonas denitrificans and vitamin B12 synthesis based on real-time capacitance measurement and online specific oxygen consumption rate (Q O2) control was established for enhancing vitamin B12 production. Results demonstrated that the threshold Q O2 value lower than 2.0 mmol/gDCW/l would greatly stimulate the state transfer from the cell number growth phase to the cell elongation phase and promote rapid vitamin B12 biosynthesis, while the vitamin B12 biosynthesis rate could also be inhibited when the rate of cell's length-to-width ratio (ratio-LW) was higher than 10:1. Furthermore, the optimal morphology controlling strategy was achieved based on online Q O2 control, which increases the appropriate active cell numbers at the former phase, and then control the elongation of ratio-LW no more than 10:1 at the vitamin B12 biosynthesis phase. The maximal vitamin B12 production reached 239.7 mg/l at 168 h, which was improved by 14.7 % compared with the control (208 mg/l). This online controlling strategy would be effectively applied for improving industrial vitamin B12 fermentation. PMID:27022751

  7. Oxygen Therapy

    MedlinePlus

    Oxygen therapy is a treatment that provides you with extra oxygen. Oxygen is a gas that your body needs to function. Normally, your lungs absorb oxygen from the air you breathe. But some conditions ...

  8. Comment on "Ribosome utilizes the minimum free energy changes to achieve the highest decoding rate and fidelity"

    NASA Astrophysics Data System (ADS)

    Savir, Yonatan; Tlusty, Tsvi

    2016-05-01

    We examined [Y. Savir and T. Tlusty, Cell 153, 471 (2013), 10.1016/j.cell.2013.03.032] the decoding performance of tRNA by the ribosome. For this purpose, we specified the kinetics of tRNA decoding and the corresponding energy landscape, from which we calculated the steady-state decoding rate RC. Following our work, Xie reexamined [P. Xie, Phys. Rev. E 92, 022716 (2015), 10.1103/PhysRevE.92.022716] the energy landscape of tRNA decoding. His analysis relies on an alternative expression for RC, while claiming that the expression we use is missing some terms. In this Comment we rederive in detail our expression for the steady-state decoding rate RC, show they hold, explain why the alternative expression for RC is inaccurate, and discuss the underlying intuition.

  9. 26 Tbit s-1 line-rate super-channel transmission utilizing all-optical fast Fourier transform processing

    NASA Astrophysics Data System (ADS)

    Hillerkuss, D.; Schmogrow, R.; Schellinger, T.; Jordan, M.; Winter, M.; Huber, G.; Vallaitis, T.; Bonk, R.; Kleinow, P.; Frey, F.; Roeger, M.; Koenig, S.; Ludwig, A.; Marculescu, A.; Li, J.; Hoh, M.; Dreschmann, M.; Meyer, J.; Ben Ezra, S.; Narkiss, N.; Nebendahl, B.; Parmigiani, F.; Petropoulos, P.; Resan, B.; Oehler, A.; Weingarten, K.; Ellermeyer, T.; Lutz, J.; Moeller, M.; Huebner, M.; Becker, J.; Koos, C.; Freude, W.; Leuthold, J.

    2011-06-01

    Optical transmission systems with terabit per second (Tbit s-1) single-channel line rates no longer seem to be too far-fetched. New services such as cloud computing, three-dimensional high-definition television and virtual-reality applications require unprecedented optical channel bandwidths. These high-capacity optical channels, however, are fed from lower-bitrate signals. The question then is whether the lower-bitrate tributary information can viably, energy-efficiently and effortlessly be encoded to and extracted from terabit per second data streams. We demonstrate an optical fast Fourier transform scheme that provides the necessary computing power to encode lower-bitrate tributaries into 10.8 and 26.0 Tbit s-1 line-rate orthogonal frequency-division multiplexing (OFDM) data streams and to decode them from fibre-transmitted OFDM data streams. Experiments show the feasibility and ease of handling terabit per second data with low energy consumption. To the best of our knowledge, this is the largest line rate ever encoded onto a single light source.

  10. Basic investigations on the performance of a normoxic polymer gel with tetrakis-hydroxy-methyl-phosphonium chloride as an oxygen scavenger: Reproducibility, accuracy, stability, and dose rate dependence

    SciTech Connect

    Bayreder, Christian; Georg, Dietmar; Moser, Ewald; Berg, Andreas

    2006-07-15

    Magnetic resonance (MR)-based polymer gel dosimetry using normoxic polymer gels, represents a new dosimetric method specially suited for high-resolution three-dimensional dosimetric problems. The aim of this study was to investigate the dose response with regard to stability, accuracy, reproducibility, and the dose rate dependence. Tetrakis-hydroxy-methyl-phosphonium chloride (THPC) is used as an oxygen scavenger, and methacrylic acid as a monomer. Accuracy, reproducibility, and dose resolution were determined for MR protocols at low spatial resolution (typical for clinical scanners), medium, and microimaging-resolution protocols at three different dose levels. The dose-response stability and preirradiation-induced variations in R2, related to the time interval between preparation and irradiation of the polymer gel, were investigated. Also postirradiation stability of the polymer gel was considered. These experiments were performed using a {sup 60}Co beam (E=1.2 MV) in a water phantom. Moreover, we investigated the dose rate dependence in the low, medium, and saturation dose region of the normoxic polymer gel using a linear accelerator at photon energy of 25 MV. MR scanning was performed on a 3 T whole body scanner (MEDSPEC 30/80, BRUKER BIOSPIN, Ettlingen, Germany) using several coils and different gradient systems adapted to the acquired spatial resolution investigated. For T2-parameter selective imaging and determination of the relaxation rate R2=1/T2, a multiple spin echo sequence with 20 equidistant echoes was used. With regard to preirradiation induced variations R2 increases significantly with the increasing time interval between the polymer gel preparation and irradiation. Only a slight increase in R2 can be observed for varying the postirradiation-time solely. The dose reproducibility at voxel volumes of about 1.4x1.4x2 mm{sup 3} is better than 2%. The accuracy strongly depends on the calibration curve. THPC represents a very effective oxygen scavenger in

  11. Electron flow to oxygen in higher plants and algae: rates and control of direct photoreduction (Mehler reaction) and rubisco oxygenase.

    PubMed

    Badger, M R; von Caemmerer, S; Ruuska, S; Nakano, H

    2000-10-29

    Linear electron transport in chloroplasts produces a number of reduced components associated with photosystem I (PS I) that may subsequently participate in reactions that reduce O2. The two primary reactions that have been extensively studied are: first, the direct reduction of O2 to superoxide by reduced donors associated with PS I (the Mehler reaction), and second, the rubisco oxygenase (ribulose 1,5-bisphosphate carboxylase oxygenase EC 4.1.1.39) reaction and associated peroxisomal and mitochondrial reactions of the photorespiratory pathway. This paper reviews a number of recent and past studies with higher plants, algae and cyanobacteria that have attempted to quantify O2 fluxes under various conditions and their contributions to a number of roles, including photon energy dissipation. In C3 and Crassulacean acid metabolism (CAM) plants, a Mehler O2 uptake reaction is unlikely to support a significant flow of electron transport (probably less than 10%). In addition, if it were present it would appear to scale with photosynthetic carbon oxidation cycle (PCO) and photosynthetic carbon reduction cycle (PCR) activity This is supported by studies with antisense tobacco plants with reduced rubisco at low and high temperatures and high light, as well as studies with potatoes, grapes and madrone during water stress. The lack of significant Mehler in these plants directly argues for a strong control of Mehler reaction in the absence of ATP consumption by the PCR and PCO cycles. The difference between C3 and C4 plants is primarily that the level of light-dependent O2 uptake is generally much lower in C4 plants and is relatively insensitive to the external CO2 concentration. Such a major difference is readily attributed to the operation of the C4 CO2 concentrating mechanism. Algae show a range of light-dependent O2 uptake rates, similar to C4 plants. As in C4 plants, the O2 uptake appears to be largely insensitive to CO2, even in species that lack a CO2 concentrating

  12. On-line and in situ monitoring of oxygen concentration and gas temperature in a reheating furnace utilizing tunable diode-laser spectroscopy

    NASA Astrophysics Data System (ADS)

    Sandström, Lars; Malmberg, Donald

    2002-09-01

    Increased demands on energy savings and quality control in metallurgical processes have created incentives for new methods to monitor and control the process. In this paper we will present a field trial that shows the potential of tunable diode-laser spectroscopy (TDLS) for simultaneous contact free measuring and monitoring of the oxygen concentration as well as the gas temperature in a reheating furnace during production. The field trials were carried out at an oil-fueled reheating furnace during 7 weeks of production. The tunable diode-laser spectrometer was measuring in situ across the preheating zone and the soaking zone in the furnace. During the campaign the oxygen concentration and the gas temperature in the furnace environment were simultaneously monitored and instantaneous variations in these parameters could easily be recorded and subsequently correlated to actual changes in the process. Furthermore, the much shorter response-time of the TDLS technique compared with conventional measurement methods such as thermocouples and extractive gas analyzers was also demonstrated during the trials. The results show the potential for the TDLS technique to be used for energy savings as well as product quality improvements by controlling the burners in the reheating furnace. The results show that it would be possible to control and optimize the oxygen concentration with TDLS in the control loop of the reheating furnace.

  13. G-CSF utilization rate and prescribing patterns in United States: associations between physician and patient factors and GCSF use

    PubMed Central

    Barnes, Gisoo; Pathak, Ashutosh; Schwartzberg, Lee

    2014-01-01

    Febrile neutropenia (FN) is a common complication among patients with chemotherapy-induced myelotoxicity and is associated with a number of negative outcomes including prolonged hospitalization, increased medical costs, increased risk of mortality, dose reductions, and delays. Granulocyte-colony-stimulating factor (G-CSF), granulocyte–macrophage-colony stimulating factor (GM-CSF), and pegylated G-CSF are effective at reducing risk and duration of neutropenia-related events. However, despite guidelines, the use of G-CSF and pegylated G-CSF in the United States has not been consistent and pattern of care studies have focused primarily on G-CSF. A number of studies found that G-CSF is underutilized in patients undergoing chemotherapy treatments associated with a high risk of FN, while being over utilized in patients with a low-risk FN. Wide variations in overuse, underuse, and misuse of G-CSF are associated with a number of physician and patient factors. Improved awareness of the guidelines, feedback to providers regarding proper usage, and understanding of chemotherapy regimens associated with very low risks as well as high risks (>20%) of FN is some of the approaches that could lead to improving care. PMID:25410813

  14. Oxygen partial pressure sensor

    DOEpatents

    Dees, D.W.

    1994-09-06

    A method for detecting oxygen partial pressure and an oxygen partial pressure sensor are provided. The method for measuring oxygen partial pressure includes contacting oxygen to a solid oxide electrolyte and measuring the subsequent change in electrical conductivity of the solid oxide electrolyte. A solid oxide electrolyte is utilized that contacts both a porous electrode and a nonporous electrode. The electrical conductivity of the solid oxide electrolyte is affected when oxygen from an exhaust stream permeates through the porous electrode to establish an equilibrium of oxygen anions in the electrolyte, thereby displacing electrons throughout the electrolyte to form an electron gradient. By adapting the two electrodes to sense a voltage potential between them, the change in electrolyte conductivity due to oxygen presence can be measured. 1 fig.

  15. Oxygen partial pressure sensor

    DOEpatents

    Dees, Dennis W.

    1994-01-01

    A method for detecting oxygen partial pressure and an oxygen partial pressure sensor are provided. The method for measuring oxygen partial pressure includes contacting oxygen to a solid oxide electrolyte and measuring the subsequent change in electrical conductivity of the solid oxide electrolyte. A solid oxide electrolyte is utilized that contacts both a porous electrode and a nonporous electrode. The electrical conductivity of the solid oxide electrolyte is affected when oxygen from an exhaust stream permeates through the porous electrode to establish an equilibrium of oxygen anions in the electrolyte, thereby displacing electrons throughout the electrolyte to form an electron gradient. By adapting the two electrodes to sense a voltage potential between them, the change in electrolyte conductivity due to oxygen presence can be measured.

  16. Laboratory study of vitrinite maturation rate as a function of temperature, time, starting material, aqueous fluid pressure, and oxygen fugacity — corroboration of prior work

    NASA Astrophysics Data System (ADS)

    Ferreiro Mählmann, R.; Ernst, W. G.

    2003-04-01

    Kinetic investigations were performed on disaggregated samples of angiosperm and gymnosperm xylite (mainly pure huminite fragments) at 2.0 kbar aqueous fluid pressure and oxygen fugacities defined by hematite-magnetite and magnetite + quartz-fayalite buffers. Individual experiments lasted from 5 to 204 days. The rates of vitrinite reflectance (VR) increase were evaluated at 200, 250, 300, and 400 ^oC isotherms; experimentally determined, approximately steady-state values for the mean %R_r are 0.54, 0.74, 1.10, and 2.25, respectively. For geological lengths of time, appropriate values of %R_r = K_0t0.076 (where K_0 is a function of temperature, and t is in days). The overall activation energy describing the kinetics of devolatilization reactions responsible for increase in VR measured in our experiments is 21.8 ± 0.3 kJ/mol. Combined with earlier rate studies conducted by Dalla Torre et al. (1997) we conclude that the rate of vitrinite maturation is virtually unaffected by oxidation state, "wet" versus "dry" conditions, and nature of the starting lignitic material (conifers, hardwood). To a small extent, elevated lithostatic pressure retards the rate of increase in VR. Different, nonsystematic trends are observed for the resinite-exudatinite-bituminite present in the lignite material and in low temperature and short runs. Strong disequilibrium was recognized in short runs of the 200 and 250 ^oC isotherms. These new run data demonstrate that VR is chiefly a function of temperature and time. In support of earlier field, theoretical, and laboratory studies, for all but geologically insignificant time intervals, vitrinite reflectance is an appropriate proxy for host-rock burial temperature. Reference: Dalla Torre, M., Ferreiro Mählmann, R. and Ernst, W.G. (1997): Geochimica Cosmochimica Acta, 61/14, 2921-2928.

  17. Improvement of oxygen transfer coefficient during Penicillium canescens culture. Influence of turbine design, agitation speed, and air flow rate on xylanase production.

    PubMed

    Gaspar, A; Strodiot, L; Thonart, P

    1998-01-01

    To improve xylanase productivity from Penicillium canescens 10-10c culture, an optimization of oxygen supply is required. Because the strain is sensitive to shear forces, leading to lower xylanase productivity as to morphological alteration, vigorous mixing is not desired. The influence of turbine design, agitation speed, and air flow rate on K1a (global mass transfer coefficient, h(-1)) and enzyme production is discussed. K1a values increased with agitation speed and air flow rate, whatever the impeller, in our assay conditions. Agitation had more influence on K1a values than air flow, when a disk-mounted blade's impeller (DT) is used; an opposite result was obtained with a hub-mounted pitched blade's impeller (PBT). Xylanase production appeared as a function of specific power (W/m3), and an optimum was found in 20 and 100 L STRs fitted with DT impellers. On the other hand, the use of a hub-mounted pitched blade impeller (PBT8), instead of a disk-mounted blade impeller (DT4), reduced the lag time of hemicellulase production and increased xylanase productivity 1.3-fold. PMID:18576019

  18. Recovery and Utilization of Extraterrestrial Resources

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This special bibliography includes the extraction, processing, and utilization of lunar, planetary, and asteroid resources; mining and excavation equipment, oxygen and propellant production; and in situ resource utilization.

  19. Medication-induced Takotsubo Cardiomyopathy presenting with cardiogenic shock-utility of extracorporeal membrane oxygenation (ECMO): case report and review of the literature.

    PubMed

    Rojas-Marte, Geurys; John, Jinu; Sadiq, Adnan; Moskovits, Norbert; Saunders, Paul; Shani, Jacob

    2015-01-01

    Takotsubo cardiomyopathy (TTC) is a transient condition that affects the myocardium and is seen mostly in post-menopausal women secondary to an emotional or physical stressor; however, certain drugs have been described as cause of this syndrome. We report the case of a young female with medication--induced TTC, who presented with cardiogenic shock as initial manifestation, treated successfully with extracorporeal membrane oxygenation (ECMO). To our knowledge, this is the first case in the literature describing the use of ECMO in cardiogenic shock due to medication-induced TTC. PMID:25172356

  20. Validation of a single-stage fixed-rate step test for the prediction of maximal oxygen uptake in healthy adults.

    PubMed

    Hansen, Dominique; Jacobs, Nele; Thijs, Herbert; Dendale, Paul; Claes, Neree

    2016-09-01

    Healthcare professionals with limited access to ergospirometry remain in need of valid and simple submaximal exercise tests to predict maximal oxygen uptake (VO2max ). Despite previous validation studies concerning fixed-rate step tests, accurate equations for the estimation of VO2max remain to be formulated from a large sample of healthy adults between age 18-75 years (n > 100). The aim of this study was to develop a valid equation to estimate VO2max from a fixed-rate step test in a larger sample of healthy adults. A maximal ergospirometry test, with assessment of cardiopulmonary parameters and VO2max , and a 5-min fixed-rate single-stage step test were executed in 112 healthy adults (age 18-75 years). During the step test and subsequent recovery, heart rate was monitored continuously. By linear regression analysis, an equation to predict VO2max from the step test was formulated. This equation was assessed for level of agreement by displaying Bland-Altman plots and calculation of intraclass correlations with measured VO2max . Validity further was assessed by employing a Jackknife procedure. The linear regression analysis generated the following equation to predict VO2max (l min(-1) ) from the step test: 0·054(BMI)+0·612(gender)+3·359(body height in m)+0·019(fitness index)-0·012(HRmax)-0·011(age)-3·475. This equation explained 78% of the variance in measured VO2max (F = 66·15, P<0·001). The level of agreement and intraclass correlation was high (ICC = 0·94, P<0·001) between measured and predicted VO2max . From this study, a valid fixed-rate single-stage step test equation has been developed to estimate VO2max in healthy adults. This tool could be employed by healthcare professionals with limited access to ergospirometry. PMID:26046474

  1. Estimation of Optimal Brachytherapy Utilization Rate in the Treatment of Malignancies of the Uterine Corpus by a Review of Clinical Practice Guidelines and the Primary Evidence

    SciTech Connect

    Thompson, Stephen R. Delaney, Geoff; Gabriel, Gabriel S.; Jacob, Susannah; Das, Prabir; Barton, Michael

    2008-11-01

    Purpose: Brachytherapy (BT) is an important treatment technique for uterine corpus malignancies. We modeled the optimal proportion of these cases that should be treated with BT-the optimal rate of brachytherapy utilization (BTU). We compared this optimal BTU rate with the actual BTU rate. Methods and Materials: Evidence-based guidelines and the primary evidence were used to construct a decision tree for BTU for malignancies of the uterine corpus. Searches of the literature to ascertain the proportion of patients who fulfilled the criteria for BT were conducted. The robustness of the model was tested by sensitivity analyses and peer review. A retrospective Patterns of Care Study of BT in New South Wales for 2003 was conducted, and the actual BTU for uterine corpus malignancies was determined. The actual BTU in other geographic areas was calculated from published reports. The differences between the optimal and actual rates of BTU were assessed. Results: The optimal uterine corpus BTU rate was estimated to be 40% (range, 36-49%). In New South Wales in 2003, the actual BTU rate was only 14% of the 545 patients with uterine corpus cancer. The actual BTU rate in 2001 was 11% in the Surveillance, Epidemiology, and End Results areas and 30% in Sweden. Conclusion: The results of this study have shown that BT for uterine corpus malignancies is underused in New South Wales and in the Surveillance, Epidemiology, and End Results areas. Our model of optimal BTU can be used as a quality assurance tool, providing an evidence-based benchmark against which can be measured actual patterns of practice. It can also be used to assist in determining the adequacy of BT resource allocation.

  2. Oxygen dynamics in photosynthetic membranes.

    NASA Astrophysics Data System (ADS)

    Savikhin, Sergei; Kihara, Shigeharu

    2008-03-01

    Production of oxygen by oxygenic photosynthetic organisms is expected to raise oxygen concentration within their photosynthetic membranes above normal aerobic values. These raised levels of oxygen may affect function of many proteins within photosynthetic cells. However, experiments on proteins in vitro are usually performed in aerobic (or anaerobic) conditions since the oxygen content of a membrane is not known. Using theory of diffusion and measured oxygen production rates we estimated the excess levels of oxygen in functioning photosynthetic cells. We show that for an individual photosynthetic cell suspended in water oxygen level is essentially the same as that for a non-photosynthetic sell. These data suggest that oxygen protection mechanisms may have evolved after the development of oxygenic photosynthesis in primitive bacteria and was driven by the overall rise of oxygen concentration in the atmosphere. Substantially higher levels of oxygen are estimated to occur in closely packed colonies of photosynthetic bacteria and in green leafs.

  3. Effects of sensitizers on cell respiration: II. The effects of hypoxic cell sensitizers on oxygen utilization in cellular and chemical models.

    PubMed Central

    Greenstock, C. L.; Biaglow, J. E.; Durand, R. E.

    1978-01-01

    The metabolic activity of nitroheterocyclic sensitizers could limit their usefulness in vivo. Biochemical mechanisms of drug metabolism, toxicity and effects on cell respiration have been studied in microsomes, and the kinetics of the simulated redox reactions determined by pulse radiolysis. Stimulated oxidation of coenzyme, glucose, ascorbate or glutathione substrate radicals by nitroheterocyclic sensitizers, with the concomitant appearance of the respective nitro radical anions, is observed. Under hypoxia, the nitro radical anions decay slowly by second order processes, forming reduced metabolites. In air, the nitro radical anions react with oxygen forming superoxide radical anions, peroxide and regenerating the drug. Nitro radical-anions also react with cytochrome-c indicating a possible interference with mitochondrial energy metabolism. PMID:277209

  4. Hydrogen Reduction of Lunar Regolith Simulants for Oxygen Production

    NASA Technical Reports Server (NTRS)

    Hegde, U.; Balasubramaniam, R.; Gokoglu, S. A.; Rogers, K.; Reddington, M.; Oryshchyn, L.

    2011-01-01

    Hydrogen reduction of the lunar regolith simulants JSC-1A and LHT-2M is investigated in this paper. Experiments conducted at NASA Johnson Space Center are described and are analyzed utilizing a previously validated model developed by the authors at NASA Glenn Research Center. The effects of regolith sintering and clumping, likely in actual production operations, on the oxygen production rate are studied. Interpretations of the obtained results on the basis of the validated model are provided and linked to increase in the effective particle size and reduction in the intra-particle species diffusion rates. Initial results on the pressure dependence of the oxygen production rate are also presented and discussed

  5. Oxygen Reduction Reaction Measurements on Platinum Electrocatalysts Utilizing Rotating Disk Electrode Technique: II. Influence of Ink Formulation, Catalyst Layer Uniformity and Thickness

    SciTech Connect

    Shinozaki, Kazuma; Zack, Jason W.; Pylypenko, Svitlana; Pivovar, Bryan S.; Kocha, Shyam S.

    2015-09-17

    Platinum electrocatalysts supported on high surface area and Vulcan carbon blacks (Pt/HSC, Pt/V) were characterized in rotating disk electrode (RDE) setups for electrochemical area (ECA) and oxygen reduction reaction (ORR) area specific activity (SA) and mass specific activity (MA) at 0.9 V. Films fabricated using several ink formulations and film-drying techniques were characterized for a statistically significant number of independent samples. The highest quality Pt/HSC films exhibited MA 870 ± 91 mA/mgPt and SA 864 ± 56 μA/cm2 Pt while Pt/V had MA 706 ± 42 mA/mgPt and SA 1120 ± 70 μA/cm2 Pt when measured in 0.1 M HClO4, 20 mV/s, 100 kPa O2 and 23±2°C. An enhancement factor of 2.8 in themeasured SA was observable on eliminating Nafion ionomer and employing extremely thin, uniform films (~4.5 μg/cm2 Pt) of Pt/HSC. The ECA for Pt/HSC (99 ± 7 m2/gPt) and Pt/V (65 ± 5 m2/gPt) were statistically invariant and insensitive to film uniformity/thickness/fabrication technique; accordingly, enhancements in MA are wholly attributable to increases in SA. Impedance measurements coupled with scanning electron microscopy were used to de-convolute the losses within the catalyst layer and ascribed to the catalyst layer resistance, oxygen diffusion, and sulfonate anion adsorption/blocking. The ramifications of these results for proton exchange membrane fuel cells have also been examined.

  6. Oxygen Reduction Reaction Measurements on Platinum Electrocatalysts Utilizing Rotating Disk Electrode Technique: II. Influence of Ink Formulation, Catalyst Layer Uniformity and Thickness

    DOE PAGESBeta

    Shinozaki, Kazuma; Zack, Jason W.; Pylypenko, Svitlana; Pivovar, Bryan S.; Kocha, Shyam S.

    2015-09-17

    Platinum electrocatalysts supported on high surface area and Vulcan carbon blacks (Pt/HSC, Pt/V) were characterized in rotating disk electrode (RDE) setups for electrochemical area (ECA) and oxygen reduction reaction (ORR) area specific activity (SA) and mass specific activity (MA) at 0.9 V. Films fabricated using several ink formulations and film-drying techniques were characterized for a statistically significant number of independent samples. The highest quality Pt/HSC films exhibited MA 870 ± 91 mA/mgPt and SA 864 ± 56 μA/cm2 Pt while Pt/V had MA 706 ± 42 mA/mgPt and SA 1120 ± 70 μA/cm2 Pt when measured in 0.1 M HClO4,more » 20 mV/s, 100 kPa O2 and 23±2°C. An enhancement factor of 2.8 in themeasured SA was observable on eliminating Nafion ionomer and employing extremely thin, uniform films (~4.5 μg/cm2 Pt) of Pt/HSC. The ECA for Pt/HSC (99 ± 7 m2/gPt) and Pt/V (65 ± 5 m2/gPt) were statistically invariant and insensitive to film uniformity/thickness/fabrication technique; accordingly, enhancements in MA are wholly attributable to increases in SA. Impedance measurements coupled with scanning electron microscopy were used to de-convolute the losses within the catalyst layer and ascribed to the catalyst layer resistance, oxygen diffusion, and sulfonate anion adsorption/blocking. The ramifications of these results for proton exchange membrane fuel cells have also been examined.« less

  7. Utility of vital signs, heart rate variability and complexity, and machine learning for identifying the need for lifesaving interventions in trauma patients.

    PubMed

    Liu, Nehemiah T; Holcomb, John B; Wade, Charles E; Darrah, Mark I; Salinas, Jose

    2014-08-01

    To date, no studies have attempted to utilize data from a combination of vital signs, heart rate variability and complexity (HRV, HRC), as well as machine learning (ML), for identifying the need for lifesaving interventions (LSIs) in trauma patients. The objectives of this study were to examine the utility of the above for identifying LSI needs and compare different LSI-associated models, with the hypothesis that an ML model would be superior in performance over multivariate logistic regression models. One hundred four patients transported from the injury scene via helicopter were selected for the study. A wireless vital signs monitor was attached to the patient's arm and used to capture physiologic data, including HRV and HRC. The power of vital sign measurements, HRV, HRC, and Glasgow Coma Scale score (GCS) to identify patients requiring LSIs was estimated using multivariate logistic regression and ML. Receiver operating characteristic (ROC) curves were also obtained. Thirty-two patients underwent 75 LSIs. After logistic regression, ROC curves demonstrated better identification for LSIs using heart rate (HR) and HRC (area under the curve [AUC] of 0.81) than using HR alone (AUC of 0.73). Likewise, ROC curves demonstrated better identification for LSIs using GCS and HRC (AUC of 0.94) than using GCS and HR (AUC of 0.92). Importantly, ROC curves demonstrated that an ML model using HR, GCS, and HRC (AUC of 0.99) had superior performance over multivariate logistic regression models for identifying the need for LSIs in trauma patients. Development of computer decision support systems should utilize vital signs, HRC, and ML in order to achieve more accurate diagnostic capabilities, such as identification of needs for LSIs in trauma patients. PMID:24727872

  8. Prognostic Significance of Transverse Relaxation Rate (R2*) in Blood Oxygenation Level-Dependent Magnetic Resonance Imaging in Patients with Invasive Breast Cancer

    PubMed Central

    Choi, Hye Young; Ko, Eun Sook; Han, Boo-Kyung; Kim, Eun Ju; Kim, Sun Mi; Lim, Yaeji; Kim, Rock Bum

    2016-01-01

    Objective To examine the relationship between magnetic resonance transverse relaxation rate (R2*) and prognostic factors. Materials and Methods A total of 159 women with invasive ductal carcinomas (IDCs) underwent breast magnetic resonance imaging (MRI) including blood oxygenation level-dependent (BOLD) sequence at 3 T. The distribution of the measured R2* values were analyzed, and the correlation between R2* and various prognostic factors (age, tumor size, histologic grade, lymphovascular invasion, and axillary lymph node status, as well as expression of estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2, p53, and Ki-67) were retrospectively assessed using patient medical records. Results The baseline R2* values of the IDCs were very heterogeneous with wide range among the patients. The mean R2* value was (32.8 ± 14.0) Hz with a median of 29.3 Hz (range 13.5–109.4 Hz). In multivariate analysis, older age was associated with decreased R2* value (P = 0.011) and IDCs with p53-overexpression showed higher R2* values than those without p53-overexpression group (P = 0.031). Other prognostic factors were not significantly correlated with R2* value. Conclusion In this study, R2* values were significantly correlated with age and expression of p53. Further studies are necessary to determine the prognostic value of BOLD-MRI. PMID:27384310

  9. The {sup 18}O:{sup 16}O of dissolved oxygen in rivers and lakes in the Amazon Basin: Determining the ratio of respiration to photosynthesis rates in freshwaters

    SciTech Connect

    Quay, P.D.; Wilbur, D.O.; Richey, J.E.

    1995-06-01

    The concentration and {sup 18}O:{sup 16}O ratio of dissolved oxygen were measured for 23 rivers and lakes of the Amazon Basin during 1988, 1990, and 1991. With only two exceptions, the rivers and lakes had dissolved oxygen concentrations that were at 20-90% of atmospheric saturation levels. The {delta}{sup 18}O of the dissolved oxygen ranged from 15 to 30% (vs. SMOW). The {delta}{sup 18}O for the lakes were the lowest at 15-23%. {delta}{sup 18}O < 24.2{per_thousand} (the atmospheric equilibrium value) are the result of photosynthetic oxygen input. The {delta}{sup 18}O of the rivers, in contrast, ranged from 24 to 30{per_thousand} > 24.2{per_thousand} resulted from respiration. Despite this clear difference between the {delta}{sup 18}O for rivers and lakes, these water bodies had similar levels of oxygen undersaturation. The {delta}{sup 18}O and dissolved oxygen concentrations are used to determine the ratio of community respiration (R) to gross photosynthesis (P) rates. R:P varied between {approximately}1 and 1.5 for lakes and between 1.5 and 4 for rivers. For all rivers and lakes, the measured {delta}{sup 18}O indicated the presence of photosynthetically produced oxygen, with the highest proportion occurring in lakes. The {delta}{sup 18}O of dissolved oxygen is a unique tracer of photosynthetic oxygen and provides, through a determination of R:P, a means of quantifying the heterotrophic state of freshwaters. 29 refs., 8 figs., 4 tabs.

  10. Development and field testing of an alternative latrine design utilizing basic oxygen furnace slag as a treatment media for pathogen removal

    NASA Astrophysics Data System (ADS)

    Stimson, J.; Suhogusoff, A. V.; Blowes, D. W.; Hirata, R. A.; Ptacek, C. J.; Robertson, W. D.; Emelko, M. B.

    2009-05-01

    In densely-populated communities in developing countries, appropriate setback distances for pit latrines often cannot be met. An alternative latrine was designed that incorporates two permeable reactive media to treat pathogens and nitrate from effluent. Basic oxygen furnace (BOF) slag in contact with wastewater effluent elevates pH to levels (> 11) that inactivate pathogens. Saturated woodchip creates reducing conditions that encourage the growth of denitrifying bacteria which remove NO3-. The field application was constructed in Santo Antônio, a peri-urban community located 25 km south of the city of São Paulo, Brazil. A 2-m diameter pit was excavated to a depth of 4 m into the sandy-clay unsaturated zone. A geotextile liner was emplaced to create saturated conditions in the 0.5-m thick woodchip barrier. Above the woodchip barrier, a 1-m thick layer of BOF slag mixed with pea gravel and sand was emplaced. A series of filter layers, grading upward from coarse sand to fine gravel, where placed above the BOF layer, and gravel was also infilled around the outer perimeter of the excavation, to ensure O2 diffusion into the design, the formation of biofilm, and degradation of organic material. A control latrine, constructed with similar hydraulic characteristics and nonreactive materials, was constructed at a locality 100 m away, in the same geological materials. Total coliform, thermotolerant coliform, and E. coli are removed by approximately 4-5 log concentration units in less than one meter of vertical transport through the BOF slag media. In the control latrine, comparable reductions in these pathogenic indicators are observed over three meters of vertical transport. Removal of sulphur-reducing Clostridia, Clostridium perfrigens and somatic coliphage are also achieved in the alternative design, but initial concentrations in effluent are low. Some measurable concentrations of pathogen indicators are measured in lysimeters below the BOF layer, but are associated

  11. A SIMPLE PHOTOMETER FOR PRECISE DETERMINATION OF DISSOLVED OXYGEN CONCENTRATION BY THE WINKLER METHOD WITH RECOMMENDATIONS FOR IMPROVING RESPIRATION RATE MEASUREMENTS IN AQUATIC ORGANISMS

    EPA Science Inventory

    A simple inexpensive photometer designed for Winkler titration end-point detection is described. The precision of replicate dissolved oxygen measurements using this instrument was 0.06-0.22%. This high precision is needed to measure the small changes in dissolved oxygen concentra...

  12. The effect of chamber mixing velocity on bias in measurement of sediment oxygen demand rates in the Tualatin River basin, Oregon

    USGS Publications Warehouse

    Doyle, Micelis C.; Rounds, Stewart

    2003-01-01

    The same resuspension effect probably exists in the Tualatin River during storm-runoff events following prolonged periods of low flow, when increased stream velocity may result in the resuspension of bottom sediments. The resuspension causes increased turbidity and increased oxygen demand, resulting in lower instream dissolved oxygen concentrations.

  13. Lunar construction utility vehicle

    NASA Technical Reports Server (NTRS)

    1989-01-01

    The lunar construction utility vehicle (LCUV) is an all-purpose construction vehicle which will aid in the robotic assembly of a lunar outpost. The LCUV will have the following capabilities: (1) must be self supporting including repairs; (2) must offload itself from a lunar lander; (3) must be telerobotic and semi-autonomous; (4) must be able to transport one space station common module; (5) must allow for man-rated operation; and (6) must be able to move lunar regolith for site preparation. This study recommends the use of an elastic tracked vehicle. Detailed material analyses of most of the LCUV components were accomplished. The body frame, made of pinned truss elements, was stress analyzed using NASTRAN. A track connection system was developed; however, kinematic and stress analyses are still required. This design recommends the use of hydrogen-oxygen fuel cells for power. Thermal control has proven to be a problem which may be the most challenging technically. A tentative solution has been proposed which utilizes an onboard and towable radiator. Detailed study of the heat dissipation requirements is needed to finalize radiator sizing. Preliminary work on a man-rated cabin has begun; however, this is not required during the first mission phase of the LCUV. Finally, still in the conceptual phases, are the communication, navigation and mechanical arm systems.

  14. Zinc-oxygen battery development program

    NASA Astrophysics Data System (ADS)

    Bourland, Deborah S.

    1991-05-01

    The purpose of this Zinc-Oxygen development program is to incorporate the improved air/oxygen cathode and zinc anode technology developed in recent years into relatively large cells (150-200 amp/hr, 25-100 hour rate) and smaller high rate cells (9-12 amp/hr, 3-12 hour rate). Existing commercial cells manufactured by Duracell and Rayovac are currently being utilized on the Space Shuttle Orbiter in a mini-oscilloscope, the crew radio, and other crew equipment. These applications provide a basis for other Orbiter systems that require portable, storable, electrical power as well as emergency power for the Space Station major payload systems power and for Space Station equipment applications.

  15. Zinc-oxygen battery development program

    NASA Technical Reports Server (NTRS)

    Bourland, Deborah S.

    1991-01-01

    The purpose of this Zinc-Oxygen development program is to incorporate the improved air/oxygen cathode and zinc anode technology developed in recent years into relatively large cells (150-200 amp/hr, 25-100 hour rate) and smaller high rate cells (9-12 amp/hr, 3-12 hour rate). Existing commercial cells manufactured by Duracell and Rayovac are currently being utilized on the Space Shuttle Orbiter in a mini-oscilloscope, the crew radio, and other crew equipment. These applications provide a basis for other Orbiter systems that require portable, storable, electrical power as well as emergency power for the Space Station major payload systems power and for Space Station equipment applications.

  16. Effect of low inspired oxygen fraction on respiratory indices in mechanically ventilated horses anaesthetised with isoflurane and medetomidine constant rate infusion.

    PubMed

    Taylor, A H; Seymour, C J

    2016-05-01

    Horses may become hypoxaemic during anaesthesia despite a high inspired oxygen fraction (FiO2). A lower FiO2 is used commonly in human beings to minimise atelectasis and to improve lung function, and previously has been shown to be of potential benefit in horses in experimental conditions. Other studies suggest no benefit to using a FiO2 of 0.5 during clinically relevant conditions; however, low FiO2 (0.65) is commonly used in practice and in a large number of studies. The present study was performed to compare the effect of a commonly used FiO2 of 0.65 versus 0.90 on calculated respiratory indices in anaesthetised mechanically ventilated horses in a clinical setting. Eighteen healthy Thoroughbred horses anaesthetised for experimental laryngeal surgery were recruited into a prospective, non-blinded, randomised clinical study. Before anaesthesia, the horses were randomly allocated into either low (0.65) or high (0.90) FiO2 groups and arterial blood gas (ABG) analysis was performed every 30 min during anaesthesia to allow for statistical analysis of respiratory indices. As expected, PaO2 was significantly lower in horses anaesthetised with a low FiO2, but was sufficient to fully saturate haemoglobin. There were no significant improvements in any of the other respiratory indices. There is no obvious benefit to be gained from the use of a FiO2 of 0.65 compared to 0.90 for mechanically ventilated Thoroughbred horses anaesthetised in lateral recumbency with isoflurane and a medetomidine constant rate infusion. PMID:27012166

  17. Assessment of the inhibition of Dengue virus infection by carrageenan via real-time monitoring of cellular oxygen consumption rates within a microfluidic device

    PubMed Central

    Huang, Shih-Hao; Lin, Yi-Syun; Wu, Chih-Wei; Wu, Chang-Jer

    2014-01-01

    A microfluidic device combined with a light modulation system was developed to assess the inhibitory effect of carrageenan on Dengue virus (DENV) infection via real-time monitoring of cellular oxygen consumption rates (OCRs). Measuring cellular OCRs, which can reflect cellular metabolic activity, enabled us to monitor the process of viral infection in real time and to rapidly determine the antiviral activity of potential drugs/chemical compounds. The time variation of the cellular OCR of single cells that were infected in situ by DENV at different multiplicity of infection (m.o.i.) values was first successfully measured within a microfluidic device. The influence of the timing of carrageenan treatment on DENV infection was then examined by real-time monitoring of cellular OCRs in three groups. Cells that were pre-treated with carrageenan and then infected with DENV served as a pre-treatment group, cells to which carrageenan was added simultaneously with DENV served as a virucide group, and cells that were pre-infected with DENV and then treated with carrageenan served as a post-treatment group. By monitoring cellular OCRs, we could rapidly evaluate the inhibitory effect of carrageenan on DENV infection, obtaining a result within 7 h and showing that carrageenan had strong and effective anti-DENV activity in the three groups. In particular, a strong inhibitory effect was observed in the virucide group. Moreover, once the virus enters host cells in the post-treatment group, the immediate treatment with carrageenan for the infected cells has higher efficiency of antiviral activity. Our proposed platform enables to perform time-course or dose-response measurements of changes in cellular metabolic activity caused by diseases, chemical compounds, and drugs via monitoring of the cellular OCR, with rapid and real-time detection. This approach provides the potential to study a wide range of biological applications in cell-based biosensing, toxicology, and drug discovery

  18. Oxygen therapy - infants

    MedlinePlus

    ... help breathing than they can get from an oxygen hood or nasal cannula, but do not need a machine to completely ... is not warm enough. Most (but not all) nasal cannulas use cool, dry oxygen. At higher flow rates, this can irritate the ...

  19. Oxygen Reduction Reaction Measurements on Platinum Electrocatalysts Utilizing Rotating Disk Electrode Technique: I. Impact of Impurities, Measurement Protocols and Applied Corrections

    SciTech Connect

    Shinozaki, Kazuma; Zack, Jason W.; Richards, Ryan M.; Pivovar, Bryan S.; Kocha, Shyam S.

    2015-07-22

    The rotating disk electrode (RDE) technique is being extensively used as a screening tool to estimate the activity of novel PEMFC electrocatalysts synthesized in lab-scale (mg) quantities. Discrepancies in measured activity attributable to glassware and electrolyte impurity levels, as well as conditioning, protocols and corrections are prevalent in the literature. Moreover, the electrochemical response to a broad spectrum of commercially sourced perchloric acid and the effect of acid molarity on impurity levels and solution resistance were also assessed. Our findings reveal that an area specific activity (SA) exceeding 2.0 mA/cm2 (20 mV/s, 25°C, 100 kPa, 0.1 M HClO4) for polished poly-Pt is an indicator of impurity levels that do not impede the accurate measurement of the ORR activity of Pt based catalysts. After exploring various conditioning protocols to approach maximum utilization of the electrochemical area (ECA) and peak ORR activity without introducing catalyst degradation, an investigation of measurement protocols for ECA and ORR activity was conducted. Down-selected protocols were based on the criteria of reproducibility, duration of experiments, impurity effects and magnitude of pseudo-capacitive background correction. In sum, statistical reproducibility of ORR activity for poly-Pt and Pt supported on high surface area carbon was demonstrated.

  20. Oxygen Reduction Reaction Measurements on Platinum Electrocatalysts Utilizing Rotating Disk Electrode Technique: I. Impact of Impurities, Measurement Protocols and Applied Corrections

    DOE PAGESBeta

    Shinozaki, Kazuma; Zack, Jason W.; Richards, Ryan M.; Pivovar, Bryan S.; Kocha, Shyam S.

    2015-07-22

    The rotating disk electrode (RDE) technique is being extensively used as a screening tool to estimate the activity of novel PEMFC electrocatalysts synthesized in lab-scale (mg) quantities. Discrepancies in measured activity attributable to glassware and electrolyte impurity levels, as well as conditioning, protocols and corrections are prevalent in the literature. Moreover, the electrochemical response to a broad spectrum of commercially sourced perchloric acid and the effect of acid molarity on impurity levels and solution resistance were also assessed. Our findings reveal that an area specific activity (SA) exceeding 2.0 mA/cm2 (20 mV/s, 25°C, 100 kPa, 0.1 M HClO4) for polishedmore » poly-Pt is an indicator of impurity levels that do not impede the accurate measurement of the ORR activity of Pt based catalysts. After exploring various conditioning protocols to approach maximum utilization of the electrochemical area (ECA) and peak ORR activity without introducing catalyst degradation, an investigation of measurement protocols for ECA and ORR activity was conducted. Down-selected protocols were based on the criteria of reproducibility, duration of experiments, impurity effects and magnitude of pseudo-capacitive background correction. In sum, statistical reproducibility of ORR activity for poly-Pt and Pt supported on high surface area carbon was demonstrated.« less

  1. Oxygen utilization and the branchial pressure gradient during ram ventilation of the shortfin mako, Isurus oxyrinchus: is lamnid shark-tuna convergence constrained by elasmobranch gill morphology?

    PubMed

    Wegner, Nicholas C; Lai, N Chin; Bull, Kristina B; Graham, Jeffrey B

    2012-01-01

    Ram ventilation and gill function in a lamnid shark, the shortfin mako, Isurus oxyrinchus, were studied to assess how gill structure may affect the lamnid-tuna convergence for high-performance swimming. Despite differences in mako and tuna gill morphology, mouth gape and basal swimming speeds, measurements of mako O(2) utilization at the gills (53.4±4.2%) and the pressure gradient driving branchial flow (96.8±26.1 Pa at a mean swimming speed of 38.8±5.8 cm s(-1)) are similar to values reported for tunas. Also comparable to tunas are estimates of the velocity (0.22±0.03 cm s(-1)) and residence time (0.79±0.14 s) of water though the interlamellar channels of the mako gill. However, mako and tuna gills differ in the sites of primary branchial resistance. In the mako, approximately 80% of the total branchial resistance resides in the septal channels, structures inherent to the elasmobranch gill that are not present in tunas. The added resistance at this location is compensated by a correspondingly lower resistance at the gill lamellae accomplished through wider interlamellar channels. Although greater interlamellar spacing minimizes branchial resistance, it also limits lamellar number and results in a lower total gill surface area for the mako relative to tunas. The morphology of the elasmobranch gill thus appears to constrain gill area and, consequently, limit mako aerobic performance to less than that of tunas. PMID:22162850

  2. Acrolein-Induced Increases in Blood Pressure and Heart Rate Are Coupled with Decreased Blood Oxygen Levels During Exposure in Hypertensive Rats

    EPA Science Inventory

    Exposure to air pollution increases the risk of cardiovascular morbidity and mortality, especially in individuals with pre-existing cardiovascular disease. Recent studies link exposure to air pollution with reduced blood oxygen saturation suggesting that hypoxia is a potential me...

  3. Solid state oxygen sensor

    DOEpatents

    Garzon, F.H.; Brosha, E.L.

    1997-12-09

    A potentiometric oxygen sensor is formed having a logarithmic response to a differential oxygen concentration while operating as a Nernstian-type sensor. Very thin films of mixed conducting oxide materials form electrode services while permitting diffusional oxygen access to the interface between the zirconia electrolyte and the electrode. Diffusion of oxygen through the mixed oxide is not rate-limiting. Metal electrodes are not used so that morphological changes in the electrode structure do not occur during extended operation at elevated temperatures. 6 figs.

  4. OXYGEN ENHANCED COMBUSTION FOR NOx CONTROL

    SciTech Connect

    Lawrence E. Bool; Jack C. Chen; David R. Thompson

    2000-07-01

    Increased environmental regulations will require utility boilers to reduce NO{sub x} emissions to less than 0.15lb/MMBtu in the near term. Conventional technologies such as Selective Catalytic Reduction (SCR) and Selective Non-Catalytic Reduction (SNCR) are unable to achieve these lowered emission levels without substantially higher costs and major operating problems. Oxygen enhanced combustion is a novel technology that allows utilities to meet the NO{sub x} emission requirements without the operational problems that occur with SCR and SNCR. Furthermore, oxygen enhanced combustion can achieve these NO{sub x} limits at costs lower than conventional technologies. The objective of this program is to demonstrate the use of oxygen enhanced combustion as a technical and economical method of meeting the EPA State Implementation Plan for NO{sub x} reduction to less than 0.15lb/MMBtu for a wide range of boilers and coal. The oxygen enhanced coal combustion program (Task 1) focused this quarter on the specific objective of exploration of the impact of oxygen enrichment on NO{sub x} formation utilizing small-scale combustors for parametric testing. Research efforts toward understanding any limitations to the applicability of the technology to different burners and fuels such as different types of coal are underway. The objective of the oxygen transport membrane (OTM) materials development program (Task 2.1) is to ascertain a suitable material composition that can be fabricated into dense tubes capable of producing the target oxygen flux under the operating conditions. This requires that the material have sufficient oxygen permeation resulting from high oxygen ion conductivity, high electronic conductivity and high oxygen surface exchange rate. The OTM element development program (Task 2.2) objective is to develop, fabricate and characterize OTM elements for laboratory and pilot reactors utilizing quality control parameters to ensure reproducibility and superior performance

  5. Cure Rates in Small Cell and Non-Small Cell Carcinoma of the Lung Utilizing High-Dose Radiotherapy and Chemotherapy

    PubMed Central

    Akbiyik, Nejat; Alexander, Leslie L.

    1986-01-01

    From 1967 to 1977, 72 patients with small cell carcinoma of the lung were seen. Thirty-five of these patients had unilaterally localized lesions (limited disease) and were treated with cobalt 60 radiation therapy (6,000 rad in six weeks) followed by chemotherapy consisting of cyclophosphamide (Cytoxan), vincristine, methotrexate and lomustine (CCNU) (Group A). The remaining 37 patients with extensive disease were treated with similar chemotherapy alone, or in combination with local palliative radiotherapy to the symptomatic area (Group B). For Group A the five-year survival rate was 20 percent, while for both groups combined, it was only 5 percent. During this same period 560 patients with non-small cell carcinomas were treated. The five-year survival rate for those patients with operable, resectable lesions was 33 percent, while for those with unilateral, inoperable, unresectable lesions, it was 10 percent. Thus, it would appear that the results in limited small cell and non-small cell carcinomas of the lung utilizing high-dose radiotherapy followed by chemotherapy are comparable, and that limited small cell carcinoma of the lung patients with high-dose radiotherapy followed by chemotherapy can survive longer than those patients with stage III, non-small cell lung carcinoma. While the two- to five-year survival rates in small cell carcinoma demonstrate no appreciable differences, in non-small cell carcinomas there are significant two- to five-year survival differences. These improved results probably are due to the increased sensitivity of small cell carcinoma to high-dose local radiotherapy and to the chemotherapeutic vulnerability of circulating and microscopic metastatic cancer cells. PMID:3012100

  6. Effects of N2O narcosis on the contraction and repayment of an oxygen debt

    NASA Technical Reports Server (NTRS)

    Schatte, C. L.; Hall, P.; Fitch, J. W.; Loader, J. E.

    1974-01-01

    The oxygen deficit, oxygen debt, and the difference between them were measured in five male and three female subjects during and after exercise while breathing either air or a normoxic mixture containing 33% N2O and nitrogen. With the exception of a higher respiratory quotient at rest in N2O, there were no statistically significant differences for oxygen consumption, carbon dioxide production, expired gas volume, heart rate or blood lactate while breathing N2O during rest, exercise, or recovery. An appreciably, but not statistically, greater mean oxygen deficit was found in N2O along with a significantly greater mean oxygen debt; deficit-debt difference was unaffected by N2O. It was speculated that N2O narcosis did not affect the ability to utilize oxygen but that the response to the greater oxygen need of exercise may have been slowed with perhaps a concomitant greater depletion of stored high energy compounds.

  7. Oxygen dynamics in periphyton communities and associated effects on phosphorus release from lake sediments

    SciTech Connect

    Carlton, R.G.

    1986-01-01

    This study used oxygen sensitive microelectrodes with tip diameters of < 30 um to investigate the effects of photosynthesis and respiration on the oxygen dynamics of several diverse periphyton communities both in situ and in laboratory microcosms. A novel flow-through system that utilized /sup 32/P radiotracer and that permitted manipulation of the velocity, flushing rate, and oxygen concentration of overlying water was developed to investigate the role of photosynthetic oxygen production on the phosphorus dynamics in lake sediments colonized by epipelic periphyton.

  8. Oxygen pressure measurement using singlet oxygen emission

    SciTech Connect

    Khalil, Gamal E.; Chang, Alvin; Gouterman, Martin; Callis, James B.; Dalton, Larry R.; Turro, Nicholas J.; Jockusch, Steffen

    2005-05-15

    Pressure sensitive paint (PSP) provides a visualization of two-dimensional pressure distributions on airfoil and model automobile surfaces. One type of PSP utilizes platinum tetra(pentafluorophenyl)porphine (PtTFPP) dissolved in a fluoro-polymer film. Since the intense 650 nm triplet emission of PtTFPP is quenched by ground state oxygen, it is possible to measure two-dimensional oxygen concentration from the 650 nm emission intensity using a Stern-Volmer-type relationship. This article reports an alternative luminescence method to measure oxygen concentration based on the porphyrin-sensitized 1270 nm singlet oxygen emission, which can be imaged with an InGaAs near infrared camera. This direct measurement of oxygen emission complements and further validates the oxygen measurement based on PtTFPP phosphorescence quenching. Initial success at obtaining a negative correlation between the 650 nm PtTFPP emission and the 1270 nm O{sub 2} emission in solution led us to additional two-dimensional film studies using surfaces coated with PtTFPP, MgTFPP, and H{sub 2}TFPP in polymers in a pressure and temperature controlled chamber.

  9. Geographic Differences in Use of Home Oxygen for Obstructive Lung Disease: A National Medicare Study

    PubMed Central

    Chan, Leighton; Giardino, Nicholas; Rubenfeld, Gordon; Baldwin, Laura-Mae; Fordyce, Meredith A.; Hart, L. Gary

    2012-01-01

    Rationale Home oxygen is the most expensive equipment item that Medicare purchases ($1.7 billion/year). Objectives To assess geographic differences in supplemental oxygen use. Methods Retrospective cohort analysis of oxygen claims for a 20% random sample of Medicare patients hospitalized for obstructive lung disease in 1999 and alive at the end of 2000. Measurements and Main Results While 33.7% of the 34,916 hospitalized patients used supplemental oxygen, there was more than a 4-fold difference between states and a greater than 6-fold difference between hospital referral regions with high/low utilization. Rocky Mountain States and Alaska had the highest utilization, while the District of Columbia and Louisiana had the lowest utilization. After adjusting for patient characteristics and elevation, high-utilization communities included low-lying areas in California, Florida, Michigan, Missouri, and Washington. Patients who were younger, male, white, and who had more comorbidities, more hospital admissions, and lived at higher altitudes and in areas of greater income also had higher odds of using supplemental oxygen. Residing in rural areas was associated with higher unadjusted oxygen use rates. After adjustment, patients living in large rural areas had higher odds of using oxygen than patients living in urban areas or in small rural areas. Conclusions There is significant geographic variation in supplemental oxygen use, even after controlling for patient and contextual factors. The Centers for Medicare & Medicaid Services should examine these issues further and enact changes that ensure patient health and fiscal responsibility. PMID:20447000

  10. Oxygen Therapy

    MedlinePlus

    ... 85-95% pure oxygen. The concentrator runs on electricity or a battery. A concentrator for home usually ... systems deliver 100% oxygen, and do not require electricity. A small canister can be filled from the ...

  11. Oxygen analyzer

    DOEpatents

    Benner, William H.

    1986-01-01

    An oxygen analyzer which identifies and classifies microgram quantities of oxygen in ambient particulate matter and for quantitating organic oxygen in solvent extracts of ambient particulate matter. A sample is pyrolyzed in oxygen-free nitrogen gas (N.sub.2), and the resulting oxygen quantitatively converted to carbon monoxide (CO) by contact with hot granular carbon (C). Two analysis modes are made possible: (1) rapid determination of total pyrolyzable oxygen obtained by decomposing the sample at 1135.degree. C., or (2) temperature-programmed oxygen thermal analysis obtained by heating the sample from room temperature to 1135.degree. C. as a function of time. The analyzer basically comprises a pyrolysis tube containing a bed of granular carbon under N.sub.2, ovens used to heat the carbon and/or decompose the sample, and a non-dispersive infrared CO detector coupled to a mini-computer to quantitate oxygen in the decomposition products and control oven heating.

  12. Oxygen analyzer

    DOEpatents

    Benner, W.H.

    1984-05-08

    An oxygen analyzer which identifies and classifies microgram quantities of oxygen in ambient particulate matter and for quantitating organic oxygen in solvent extracts of ambient particulate matter. A sample is pyrolyzed in oxygen-free nitrogen gas (N/sub 2/), and the resulting oxygen quantitatively converted to carbon monoxide (CO) by contact with hot granular carbon (C). Two analysis modes are made possible: (1) rapid determination of total pyrolyzable obtained by decomposing the sample at 1135/sup 0/C, or (2) temperature-programmed oxygen thermal analysis obtained by heating the sample from room temperature to 1135/sup 0/C as a function of time. The analyzer basically comprises a pyrolysis tube containing a bed of granular carbon under N/sub 2/, ovens used to heat the carbon and/or decompose the sample, and a non-dispersive infrared CO detector coupled to a mini-computer to quantitate oxygen in the decomposition products and control oven heating.

  13. Inner retinal oxygen metabolism in the 50/10 oxygen-induced retinopathy model

    PubMed Central

    Soetikno, Brian T.; Yi, Ji; Shah, Ronil; Liu, Wenzhong; Purta, Patryk; Zhang, Hao F.; Fawzi, Amani A.

    2015-01-01

    Retinopathy of prematurity (ROP) represents a major cause of childhood vision loss worldwide. The 50/10 oxygen-induced retinopathy (OIR) model mimics the findings of ROP, including peripheral vascular attenuation and neovascularization. The oxygen metabolism of the inner retina has not been previously explored in this model. Using visible-light optical coherence tomography (vis-OCT), we measured the oxygen saturation of hemoglobin and blood flow within inner retinal vessels, enabling us to compute the inner retinal oxygen delivery (irDO2) and metabolic rate of oxygen (irMRO2). We compared these measurements between age-matched room-air controls and rats with 50/10 OIR on postnatal day 18. To account for a 61% decrease in the irDO2 in the OIR group, we found an overall statistically significant decrease in retinal vascular density affecting the superficial and deep retinal vascular capillary networks in rats with OIR compared to controls. Furthermore, matching the reduced irDO2, we found a 59% decrease in irMRO2, which we correlated with a statistically significant reduction in retinal thickness in the OIR group, suggesting that the decreased irMRO2 was due to decreased neuronal oxygen utilization. By exploring these biological and metabolic changes in great detail, our study provides an improved understanding of the pathophysiology of OIR model. PMID:26576731

  14. Rhenium-Oxygen Interactions at High Temperatures

    NASA Technical Reports Server (NTRS)

    Jacobson, Nathan S.; Myers, Dwight L.; Zhu, Dongming; Humphrey, Donald

    2000-01-01

    The reaction of pure rhenium metal with dilute oxygen/argon mixtures was studied from 600 to 1400 C. Temperature, oxygen pressure, and flow rates were systematically varied to determine the rate-controlling steps. At lower temperatures the oxygen/rhenium chemical reaction is rate limiting; at higher temperatures gas-phase diffusion of oxygen through the static boundary layer is rate limiting. At all temperatures post-reaction microstructures indicate preferential attack along certain crystallographic planes and defects.

  15. Hybrid membrane--PSA system for separating oxygen from air

    DOEpatents

    Staiger, Chad L.; Vaughn, Mark R.; Miller, A. Keith; Cornelius, Christopher J.

    2011-01-25

    A portable, non-cryogenic, oxygen generation system capable of delivering oxygen gas at purities greater than 98% and flow rates of 15 L/min or more is described. The system consists of two major components. The first component is a high efficiency membrane capable of separating argon and a portion of the nitrogen content from air, yielding an oxygen-enriched permeate flow. This is then fed to the second component, a pressure swing adsorption (PSA) unit utilizing a commercially available, but specifically formulated zeolite compound to remove the remainder of the nitrogen from the flow. The system is a unique gas separation system that can operate at ambient temperatures, for producing high purity oxygen for various applications (medical, refining, chemical production, enhanced combustion, fuel cells, etc . . . ) and represents a significant advance compared to current technologies.

  16. Effect of storage on the respirometric relationship between substrate utilization and microbial growth.

    PubMed

    Ciggin, A S; Orhon, D

    2014-09-01

    The paper evaluated the impact of substrate storage on the respirometric assessment of process stoichiometry based on oxygen uptake rate (OUR) measurements. Two parallel sequencing batch reactors were operated with pulse feeding of synthetic substrate mixture at a sludge age of 8 days and 2 days. During the cycle experiments with acetate, 40-45% of acetate was converted to polyhydroxybutyrate, which was partly consumed during each cycle. Respirometric analysis also yielded OUR profiles for the corresponding cyclic operation. A mass balance expression was derived based on oxygen utilization. Oxygen demands calculated on the basis of partial PHB utilization closely matched the experimental values retrieved from OUR profiles within limits of analytical precision. The relative contribution of storage mechanism represented more than 50% of overall oxygen demand. Substrate storage, when totally disregarded or not properly evaluated, was observed to involve an error of around 10% on overall the oxygen demand. PMID:24997376

  17. Module for Oxygenating Water without Generating Bubbles

    NASA Technical Reports Server (NTRS)

    Gonzalez-Martin, Anuncia; Sidik, Reyimjan; Kim, Jinseong

    2004-01-01

    A module that dissolves oxygen in water at concentrations approaching saturation, without generating bubbles of oxygen gas, has been developed as a prototype of improved oxygenators for water-disinfection and water-purification systems that utilize photocatalyzed redox reactions. Depending on the specific nature of a water-treatment system, it is desirable to prevent the formation of bubbles for one or more reasons: (1) Bubbles can remove some organic contaminants from the liquid phase to the gas phase, thereby introducing a gas-treatment problem that complicates the overall water-treatment problem; and/or (2) in some systems (e.g., those that must function in microgravity or in any orientation in normal Earth gravity), bubbles can interfere with the flow of the liquid phase. The present oxygenation module (see Figure 1) is a modified version of a commercial module that contains >100 hollow polypropylene fibers with a nominal pore size of 0.05 m and a total surface area of 0.5 m2. The module was originally designed for oxygenation in a bioreactor, with no water flowing around or inside the tubes. The modification, made to enable the use of the module to oxygenate flowing water, consisted mainly in the encapsulation of the fibers in a tube of Tygon polyvinyl chloride (PVC) with an inside diameter of 1 in. (approx.=25 mm). In operation, water is pumped along the insides of the hollow fibers and oxygen gas is supplied to the space outside the hollow tubes inside the PVC tube. In tests, the pressure drops of water and oxygen in the module were found to be close to zero at water-flow rates ranging up to 320 mL/min and oxygen-flow rates up to 27 mL/min. Under all test conditions, no bubbles were observed at the water outlet. In some tests, flow rates were chosen to obtain dissolved-oxygen concentrations between 25 and 31 parts per million (ppm) . approaching the saturation level of approx.=35 ppm at a temperature of 20 C and pressure of 1 atm (approx.=0.1 MPa). As one

  18. Oxygen metabolism, oxygen extraction and positron emission tomography: Historical perspective and impact on basic and clinical neuroscience.

    PubMed

    Baron, Jean-Claude; Jones, Terry

    2012-06-01

    Oxygen utilization is central to the human brain's high metabolic rate. Measurement of this fundamental process, in both disease and health, has been a focus of research attention over the last 35 years. This review plots the course of the use of oxygen-15 to study regional cerebral oxygen extraction and metabolism using Positron Emission Tomography (PET) in disease and in health. The scientific discoveries and resulting conceptual changes to both basic and clinical neuroscience, as well as the new methodological approaches brought about by this area of research, are also summarized. We conclude with a brief overview of the current status of oxygen-15 PET in neuroscience, along with our visions for future developments and applications. PMID:22227130

  19. Wastewater treatment with zero dissolved oxygen

    SciTech Connect

    Hirl, P.J.

    1998-07-01

    Many wastewater treatment plants operate their biological reactors inefficiently because the aeration is not adjusted so that the oxygen supply rate equals the microbial oxygen demand in real times. Tapered aeration systems vary aeration based on the oxygen demand profile but these systems are static. Dynamic oxygen control systems have been successful but do not operate at low dissolved oxygen concentrations. The purpose of the research described is to develop a control system and reactor operating strategies to dynamically change the aeration rate to match the oxygen uptake rate while maintaining the dissolve oxygen concentration less than 0.5 mg/L. Though, low dissolved oxygen operation can reduce the rate of carbon degradation and/or promote filamentous bulking, it also maximizes the oxygen transfer rate and can promote simultaneous nitrification and denitrification. Development and testing of a control system and operating strategies at the bench scale is in progress.

  20. Oxygen production System Models for Lunar ISRU

    NASA Technical Reports Server (NTRS)

    Santiago-Maldonado, Edgardo

    2007-01-01

    In-Situ Resource Utilization (ISRU) seeks to make human space exploration feasible; by using available resources from a planet or the moon to produce consumables, parts, and structures that otherwise would be brought from Earth. Producing these in situ reduces the mass of such that must be launched and doing so allows more payload mass' for each mission. The production of oxygen from lunar regolith, for life support and propellant, is one of the tasks being studied under ISRU. NASA is currently funding three processes that have shown technical merit for the production of oxygen from regolith: Molten Salt Electrolysis, Hydrogen Reduction of Ilmenite, and Carbothermal Reduction. The ISRU program is currently developing system models of, the , abovementioned processes to: (1) help NASA in the evaluation process to select the most cost-effective and efficient process for further prototype development, (2) identify key parameters, (3) optimize the oxygen production process, (4) provide estimates on energy and power requirements, mass and volume.of the system, oxygen production rate, mass of regolith required, mass of consumables, and other important parameters, and (5) integrate into the overall end-to-end ISRU system model, which could be integrated with mission architecture models. The oxygen production system model is divided into modules that represent unit operations (e.g., reactor, water electrolyzer, heat exchanger). Each module is modeled theoretically using Excel and Visual Basic for Applications (VBA), and will be validated using experimental data from on-going laboratory work. This modularity (plug-n-play) feature of each unit operation allows the use of the same model on different oxygen production systems simulations resulting in comparable results. In this presentation, preliminary results for mass, power, volume will be presented along with brief description of the oxygen production system model.

  1. Nasal high flow oxygen therapy in patients with COPD reduces respiratory rate and tissue carbon dioxide while increasing tidal and end-expiratory lung volumes: a randomised crossover trial

    PubMed Central

    Fraser, John F; Spooner, Amy J; Dunster, Kimble R; Anstey, Chris M; Corley, Amanda

    2016-01-01

    Abstract Patients with COPD using long-term oxygen therapy (LTOT) over 15 h per day have improved outcomes. As inhalation of dry cold gas is detrimental to mucociliary clearance, humidified nasal high flow (NHF) oxygen may reduce frequency of exacerbations, while improving lung function and quality of life in this cohort. In this randomised crossover study, we assessed short-term physiological responses to NHF therapy in 30 males chronically treated with LTOT. LTOT (2–4 L/min) through nasal cannula was compared with NHF at 30 L/min from an AIRVO through an Optiflow nasal interface with entrained supplemental oxygen. Comparing NHF with LTOT: transcutaneous carbon dioxide (TcCO2) (43.3 vs 46.7 mm Hg, p<0.001), transcutaneous oxygen (TcO2) (97.1 vs 101.2 mm Hg, p=0.01), I:E ratio (0.75 vs 0.86, p=0.02) and respiratory rate (RR) (15.4 vs 19.2 bpm, p<0.001) were lower; and tidal volume (Vt) (0.50 vs 0.40, p=0.003) and end-expiratory lung volume (EELV) (174% vs 113%, p<0.001) were higher. EELV is expressed as relative change from baseline (%Δ). Subjective dyspnoea and interface comfort favoured LTOT. NHF decreased TcCO2, I:E ratio and RR, with a concurrent increase in EELV and Vt compared with LTOT. This demonstrates a potential mechanistic rationale behind the improved outcomes observed in long-term treatment with NHF in oxygen-dependent patients. Trial registration number ACTRN12613000028707. PMID:27015801

  2. Effect of channelling on water balance, oxygen diffusion and oxidation rate in mine waste rock with an inclined multilayer soil cover

    NASA Astrophysics Data System (ADS)

    Song, Qing; Yanful, Ernest K.

    2010-05-01

    Engineered soil covers provide an option to mitigate acid rock drainage through reduced water flow and gaseous oxygen influx to underlying mine waste. Channels such as fissures, cracks or fractures developed in the barrier may influence the long-term performance of the soil cover. However, limited published information is available on the extent to which soil cover performance is impacted by these fissures and cracks. This study was conducted to investigate the effect of channelling in a barrier layer on water flow and oxygen transport in a soil cover. Two inclined (a slope of 20%) multilayer soil covers were examined under laboratory conditions. One cover had a 10-cm wide sand-filled channel in a compacted barrier layer (silty clay) at the upslope section, while the other cover was a normal one without the channel pathway. The soil covers were installed in plastic boxes measuring 120 cm × 120 cm × 25 cm (width × height × thickness). The sand-filled channel was designed to represent the aggregate of fissures and cracks that may be present in the compacted barrier. The soil covers were subjected to controlled drying and wetting periods selected to simulate field situation at the Whistle mine site near Capreol, Ontario, Canada. The measured results indicated that interflow decreased from 72.8% of the total precipitation in the soil cover without channel flow to 35.3% in the cover with channel flow, and percolation increased from zero in the normal soil cover to 43.0% of the total precipitation in the cover with channel flow. Gaseous oxygen transfer into the waste rock below the cover soils was 1091 times greater in the cover with channel than in the soil cover without channel. The channel pathway present in the barrier layer acted as a major passage for water movement and gaseous oxygen diffusion into the waste rock layer, thus decreasing the performance of the soil cover. The spacing of the channel with respect to the length of the test box is similar to those

  3. High Selectivity Oxygen Delignification

    SciTech Connect

    Arthur J. Ragauskas Lucian A. Lucia Hasan Jameel

    2005-09-30

    The overall objective of this program was to develop improved extended oxygen delignification (EOD) technologies for current U.S. pulp mill operations. This was accomplished by: (1) Identifying pulping conditions that optimize O and OO performance; (2) Identifying structural features of lignin that enhance reactivity towards EOD of high kappa pulps; (3) Identifying factors minimizing carbohydrate degradation and improve pulp strength of EOD high kappa pulps; (4) Developing a simple, reproducible method of quantifying yield gains from EOD; and (5) Developing process conditions that significantly reduce the capital requirements of EOD while optimizing the yield benefits. Key research outcomes included, demonstrating the use of a mini-O sequence such as (E+O)Dkf:0.05(E+O) or Dkf:0.05(E+O)(E+O) without interstage washing could capture approximately 60% of the delignification efficiency of a conventional O-stage without the major capital requirements associated with an O-stage for conventional SW kraft pulps. The rate of formation and loss of fiber charge during an O-stage stage can be employed to maximize net fiber charge. Optimal fiber charge development and delignification are two independent parameters and do not parallel each other. It is possible to utilize an O-stage to enhance overall cellulosic fiber charge of low and high kappa SW kraft pulps which is beneficial for physical strength properties. The application of NIR and multi-variant analysis was developed into a rapid and simple method of determining the yield of pulp from an oxygen delignification stage that has real-world mill applications. A focus point of this program was the demonstration that Kraft pulping conditions and oxygen delignification of high and low-kappa SW and HW pulps are intimately related. Improved physical pulp properties and yield can be delivered by controlling the H-factor and active alkali charge. Low AA softwood kraft pulp with a kappa number 30 has an average improvement of 2% in

  4. Isotopic exchange in mineral-fluid systems. 4. The crystal chemical controls on oxygen isotope exchange rates in carbonate-H{sub 2}O and layer silicate-H{sub 2}O systems

    SciTech Connect

    Cole, D.R.

    2000-03-01

    Oxygen isotope exchange between minerals and water in systems far from chemical equilibrium is controlled largely by surface reactions such as dissolution-precipitation. In many cases, this behavior can be modeled adequately by a simple pseudo-first order rate model that accounts for changes in surface area of the solid. Previous modeling of high temperature isotope exchange data for carbonates, sulfates, and silicates indicated that within a given mineral group there appears to be a systematic relationship between rate and mineral chemistry. The author tested this idea by conducting oxygen isotope exchange experiments in the systems, carbonate-H{sub 2}O and layer silicate-H{sub 2}O at 300 and 350 C, respectively. Witherite (BaCO{sub 3}), strontianite (SrCO{sub 3}) and calcite (CaCO{sub 3}) were reacted with pure H{sub 2}O for different lengths of time (271--1,390 H) at 300 C and 100 bars. The layer silicates, chlorite, biotite and muscovite were reacted with H{sub 2}O for durations ranging from 132 to 3,282 h at 350 C and 250 bars. A detailed survey of grain sizes and grain habits using scanning electron microscopy (SEM) indicated that grain regrowth occurred in all experiments to varying extents. The isotopic rates (ln r) for the carbonate-H{sub 2}O system are {minus}20.75 {+-} 0.44, {minus}18.95 {+-} 0.62 and {minus}18.51 {+-} 0.48 mol O/m{sup 2} s for calcite, strontianite and witherite, respectively. The oxygen isotope exchange rates for layer silicate-H{sub 2}O systems are {minus}23.99 {+-} 0.89, {minus}23.14 {+-} 0.74 and {minus}22.40 {+-} 0.66 mol O/m{sup 2} s for muscovite, biotite and chlorite, respectively.

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

    SciTech Connect

    Stevenson, J.W.; Armstrong, T.R.; Armstrong, B.L.

    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.

  6. Oxygen safety

    MedlinePlus

    ... Watch out for splattering grease. It can catch fire. Keep children with oxygen away from the stove top and oven. Cooking ... under the bed. Keep liquids that may catch fire away from your oxygen. This includes cleaning products that contain oil, grease, ...

  7. Impact of a web-based personally controlled health management system on influenza vaccination and health services utilization rates: a randomized controlled trial

    PubMed Central

    Sintchenko, Vitali; Crimmins, Jacinta; Magrabi, Farah; Gallego, Blanca; Coiera, Enrico

    2012-01-01

    Objective To assess the impact of a web-based personally controlled health management system (PCHMS) on the uptake of seasonal influenza vaccine and primary care service utilization among university students and staff. Materials and methods A PCHMS called Healthy.me was developed and evaluated in a 2010 CONSORT-compliant two-group (6-month waitlist vs PCHMS) parallel randomized controlled trial (RCT) (allocation ratio 1:1). The PCHMS integrated an untethered personal health record with consumer care pathways, social forums, and messaging links with a health service provider. Results 742 university students and staff met inclusion criteria and were randomized to a 6-month waitlist (n=372) or the PCHMS (n=370). Amongst the 470 participants eligible for primary analysis, PCHMS users were 6.7% (95% CI: 1.46 to 12.30) more likely than the waitlist to receive an influenza vaccine (waitlist: 4.9% (12/246, 95% CI 2.8 to 8.3) vs PCHMS: 11.6% (26/224, 95% CI 8.0 to 16.5); χ2=7.1, p=0.008). PCHMS participants were also 11.6% (95% CI 3.6 to 19.5) more likely to visit the health service provider (waitlist: 17.9% (44/246, 95% CI 13.6 to 23.2) vs PCHMS: 29.5% (66/224, 95% CI: 23.9 to 35.7); χ2=8.8, p=0.003). A dose–response effect was detected, where greater use of the PCHMS was associated with higher rates of vaccination (p=0.001) and health service provider visits (p=0.003). Discussion PCHMS can significantly increase consumer participation in preventive health activities, such as influenza vaccination. Conclusions Integrating a PCHMS into routine health service delivery systems appears to be an effective mechanism for enhancing consumer engagement in preventive health measures. Trial registration Australian New Zealand Clinical Trials Registry ACTRN12610000386033. http://www.anzctr.org.au/trial_view.aspx?id=335463. PMID:22582203

  8. Oxygen-Free Welding Contact Tips

    NASA Technical Reports Server (NTRS)

    Pike, James F.

    1993-01-01

    Contact tips for gas/metal arc welding (GMAW) fabricated from oxygen-free copper. Prototype tips tested in robotic welding, for which application intended. Reduces electrical erosion, increases electrical conductivity, and reduces mechanical wear. Productivity of robotic welding increases while time during welding interrupted for removal and replacement of contact tips minimal. Improves alignment of joints and filler metal, reducing rate of rejection and repair of unacceptable weldments. Utility extends beyond aerospace industry to mass production of various types of hardware, including heavy off-highway construction equipment.

  9. The nature of undergraduates' conceptual understanding of oxygen transport and utilization in humans: Can cardiopulmonary simulation software enhance learning of propositional knowledge and/or diagnose alternative conceptions in novices and intermediates?

    NASA Astrophysics Data System (ADS)

    Wissing, Dennis Robert

    The purpose of the this research was to explore undergraduates' conceptual development for oxygen transport and utilization, as a component of a cardiopulmonary physiology and advanced respiratory care course in the allied health program. This exploration focused on the student's development of knowledge and the presence of alternative conceptions, prior to, during, and after completing cardiopulmonary physiology and advanced respiratory care courses. Using the simulation program, SimBioSysTM (Samsel, 1994), student-participants completed a series of laboratory exercises focusing on cardiopulmonary disease states. This study examined data gathered from: (1) a novice group receiving the simulation program prior to instruction, (2) a novice group that experienced the simulation program following course completion in cardiopulmonary physiology, and (3) an intermediate group who experienced the simulation program following completion of formal education in Respiratory Care. This research was based on the theory of Human Constructivism as described by Mintzes, Wandersee, and Novak (1997). Data-gathering techniques were based on theories supported by Novak (1984), Wandersee (1997), and Chi (1997). Data were generated by exams, interviews, verbal analysis (Chi, 1997), and concept mapping. Results suggest that simulation may be an effective instructional method for assessing conceptual development and diagnosing alternative conceptions in undergraduates enrolled in a cardiopulmonary science program. Use of simulation in conjunction with clinical interview and concept mapping may assist in verifying gaps in learning and conceptual knowledge. This study found only limited evidence to support the use of computer simulation prior to lecture to augment learning. However, it was demonstrated that students' prelecture experience with the computer simulation helped the instructor assess what the learner knew so he or she could be taught accordingly. In addition, use of computer

  10. 41 CFR 50-204.67 - Oxygen.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 41 Public Contracts and Property Management 1 2012-07-01 2009-07-01 true Oxygen. 50-204.67 Section..., Vapors, Fumes, Dusts, and Mists § 50-204.67 Oxygen. The in-plant transfer, handling, storage, and utilization of oxygen as a liquid or a compressed gas shall be in accordance with Compressed Gas...

  11. 41 CFR 50-204.67 - Oxygen.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 1 2010-07-01 2010-07-01 true Oxygen. 50-204.67 Section..., Vapors, Fumes, Dusts, and Mists § 50-204.67 Oxygen. The in-plant transfer, handling, storage, and utilization of oxygen as a liquid or a compressed gas shall be in accordance with Compressed Gas...

  12. 41 CFR 50-204.67 - Oxygen.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 41 Public Contracts and Property Management 1 2014-07-01 2014-07-01 false Oxygen. 50-204.67..., Vapors, Fumes, Dusts, and Mists § 50-204.67 Oxygen. The in-plant transfer, handling, storage, and utilization of oxygen as a liquid or a compressed gas shall be in accordance with Compressed Gas...

  13. 41 CFR 50-204.67 - Oxygen.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 41 Public Contracts and Property Management 1 2013-07-01 2013-07-01 false Oxygen. 50-204.67..., Vapors, Fumes, Dusts, and Mists § 50-204.67 Oxygen. The in-plant transfer, handling, storage, and utilization of oxygen as a liquid or a compressed gas shall be in accordance with Compressed Gas...

  14. 41 CFR 50-204.67 - Oxygen.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 41 Public Contracts and Property Management 1 2011-07-01 2009-07-01 true Oxygen. 50-204.67 Section..., Vapors, Fumes, Dusts, and Mists § 50-204.67 Oxygen. The in-plant transfer, handling, storage, and utilization of oxygen as a liquid or a compressed gas shall be in accordance with Compressed Gas...

  15. Oxygen therapy and intraocular oxygenation.

    PubMed Central

    Jampol, L M

    1987-01-01

    When delivered to the corneal surface of rabbits or monkeys, 100% oxygen can significantly increase the pO2 in the aqueous humor. Under hyperbaric conditions (two atmospheres), an observed rise in the aqueous pO2 in rabbits breathing room air can be increased further by exposing the rabbit cornea to 100% oxygen. The high oxygen levels under hyperbaric conditions are mediated by intravascular and transcorneal delivery of oxygen. The increase in the pO2 levels in the aqueous can prevent sickling of intracameral human erythrocytes containing sickle hemoglobin. Thus, oxygen therapy transcorneally or systemically could potentially be used to treat a sickle cell hyphema. The exposure of rabbit eyes to 100% oxygen at the corneal surface is followed by autoregulation (constriction) of the iris vasculature. We could demonstrate no constriction in the eyes of two normal human volunteers or of four patients with chronic stable rubeosis iridis. Preretinal vitreous pO2 levels can be significantly raised by exposing monkeys to hyperbaric 100% oxygen. This procedure may be of value in treating acute, reversible ischemic inner retinal diseases. Transcorneal or vascular delivery of oxygen to the eye under normobaric or hyperbaric conditions may be effective in treating ischemic diseases of the anterior segment, such as anterior segment necrosis or rubeosis iridis, or ischemic inner retinal diseases. Images FIGURE 2 FIGURE 3 FIGURE 4 FIGURE 5 B FIGURE 5 C FIGURE 5 A FIGURE 6 PMID:3447339

  16. The Absolute Rates of the Solution Phase Addition of Atomic Hydrogen to a Vinyl Ether and a Vinyl Ester. The Effect of Oxygen Substitution on Hydrogen Atom Reactivity with Olefins

    SciTech Connect

    Tanner, D. D.; Kandanarachchi, P.; Das, N. C.; Franz, James A.

    2003-04-08

    The reactions of vinyl butyl ether and vinyl butyrate with atomic hydrogen and deuterium lead to addition of atomic hydrogen to the terminal position of the olefins. This observation is consistent with the reactions carried out earlier with other olefins. Both the absolute rates of addition to vinylbutyl ether and vinyl butyrate in acetone and hexane were carried out at several temperatures. The relative rates are consistent with only modest stabilization of the transition state of the radical adduct by the ??-o substituent compared with hydrogen atom addition to 1-octene. The relative rates measured in acetone and hexane indicate no significant differential solvation of ground state relative to the transition structures of the hydrogen atom addition. The kinetics reveal that the early transition states of hydrogen atom addition exhibit little selectivity (vinyl ether versus simple olefin) in either abstraction of hydrogen ??- to the oxygen or by terminal addition to the olefinic ether, reflecting the modest influence of the increased enthalpy of reaction associated with resonance stabilization by the oxygen substituent at the developing radical site.

  17. Absolute Rates of the Solution-Phase Addition of Atomic Hydrogen to a Vinyl Ether and a Vinyl Ester: Effect of Oxygen Substitution on Hydrogen Atom Reactivity with Olefins

    SciTech Connect

    Tanner, D D.; Kandanarachchi, P; Das, N. C.; Franz, James A.

    2003-04-08

    The reactions of vinyl butyl ether and vinyl butyrate with atomic hydrogen and deuterium lead to addition at the terminal position of the olefins. This observation is consistent with the reactions carried out earlier with other olefins. Both of the absolute rates of addition to vinylbutyl ether and vinyl butyrate, in acetone and hexane, were measured at several temperatures. The relative rates are consistent with only modest stabilization of the transition state of the radical adduct by the R-O substituent compared with that of hydrogen atom addition to 1-octene. The relative rates measured in acetone and hexane indicate no significant differential solvation of the ground state relative to the transition structures of the hydrogen atom addition. The kinetics reveal that the early transition states for hydrogen atom addition exhibit little selectivity (vinyl ether versus simple olefin) in either the abstraction of hydrogen R to the oxygen or by terminal addition to the olefinic ether and reflects the modest influence of the increased enthalpy of reaction associated with resonance stabilization by the oxygen substituent at the developing radical site.

  18. Effect of ultrasonic frequency on H2O2 sonochemical formation rate in aqueous nitric acid solutions in the presence of oxygen.

    PubMed

    Dalodière, Elodie; Virot, Matthieu; Moisy, Philippe; Nikitenko, Sergey I

    2016-03-01

    The influence of the ultrasonic frequency (20 kHz, 207 kHz, and 615 kHz) towards the formation kinetics of H2O2 under Ar and Ar/(20 vol.%)O2 atmospheres was evaluated in pure water and aqueous nitric solutions. Results obtained at low frequency ultrasound demonstrate that hydrogen peroxide formation is enhanced under an Ar/O2 gas mixture whatever the sonicated medium. Nevertheless, H2O2 yields are higher in aqueous nitric solutions whatever the nature of the saturating gas. These observations are consistent at high frequency ultrasound under Ar gas notwithstanding higher yields for H2O2. Surprisingly, an inverse tendency is observed for high frequency sonolysis carried out under an Ar/O2 atmosphere: higher yields of H2O2 are measured in pure water. Further studies in the presence of pure Ar revealed a more important decomposition of nitric acid under high frequency ultrasound leading to higher yields of both HNO2 in the liquid phase and NO in the gas phase. In the presence of Ar/O2 mixture, the intrabubble oxidation of NO causes cavitation bubble depletion in O2 leading to the drop of H2O2 yield. On the other hand, it was found that for Ar/(20 vol.%)O2 mixture there is no influence of oxygen on HNO2 yield whatever the ultrasonic frequency; this is most likely explained by two processes: (i) HNO2 formation results from nitrate-ion thermolysis in the liquid reaction zone surrounding the cavitation bubble, and (ii) effective intrabubble oxidation of NOx species by oxygen to nitrate-ion. PMID:26584999

  19. The FLUORINE-17(PROTON, PHOTON)NEON-18 and Oxygen -14(ALPHA Particle, PROTON)FLUORINE-17 Reaction Rates and the Structure of NEON-18 (NEON-18, FLUORINE-17, Oxygen -14, Astrophysical Hydrogen Burning)

    NASA Astrophysics Data System (ADS)

    Hahn, Kevin Insik

    1993-01-01

    The 14O(alpha,p) 17F and ^ {17}F(p,gamma)18Ne reactions play crucial roles in the advanced stages of astrophysical hydrogen burning. The ^{14 }O(alpha,p)^ {17}F(p,gamma) ^ {18}Ne(beta^+nu) 18F(p,alpha)^ {15}O reaction sequence can provide a path around the relatively slow positron decay of 14O in the HCNO cycle, while the similar reaction sequence, ^{14 }O(alpha ,p) 17F(p,gamma)^ {18}Ne(beta ^+nu) 18F(p,gamma)^ {19}Ne, can provide an alternate path from the HCNO cycle to the rp-process. The 17F(p,gamma)18Ne reaction rate could provide the principal source of 18O. Under some astrophysical conditions, the ^{14 }O(alpha,p)^ {17}F reaction is expected to compete with the 15O(alpha, gamma)19Ne reaction in providing a path through which nuclei involved in the HCNO cycle can be transformed into heavier nuclei with Z >= 10.. In order to better determine the rates of these two reactions, we measured the properties of the resonances in 18Ne; the excitation energies, the spins, and the partial and total widths of the relevant resonances. By comparing the previously observed states in 18Ne to the well-studied isospin mirror nucleus, ^{18 }O, it is clear that there are a number of missing levels in 18Ne in the region rm Ex > 4 MeV. These missing states in ^ {18}Ne could be important in determining the 17F(p, gamma)18rm Ne and 14O(alpha ,p)17F reaction rates. We have studied the ^{12 }C(12C,^6He)^{18 }Ne, 20rm Ne(p{,}t)18Ne, and 16O(^3He{, }n)18Ne reactions to measure new nuclear structure information of ^{18 }Ne. From our experiments, we have the following major results: (a) an evidence of the 3^+ <=vel at E_{rm x} = 4.56 MeV, (b) new levels at E_ {rm x} = 6.15 MeV, 7.12 MeV, 7.35 MeV, 7.62 MeV, 8.30 MeV, (8.45 MeV), 8.55 MeV, 8.94 MeV, and 9.58 MeV. (c) new J^pi assignments to the 5.11/5.15-MeV doublet and the 6.15-MeV state. Our discovery of the 3^+<=vel at an energy ~230 keV higher than calculated by Wiescher, Gorres, and Thielemann causes the contribution of the 17 F

  20. Fuel cell oxygen electrode

    DOEpatents

    Shanks, Howard R.; Bevolo, Albert J.; Danielson, Gordon C.; Weber, Michael F.

    1980-11-04

    An oxygen electrode for a fuel cell utilizing an acid electrolyte has a substrate of an alkali metal tungsten bronze of the formula: A.sub.x WO.sub.3 where A is an alkali metal and x is at least 0.2, which is covered with a thin layer of platinum tungsten bronze of the formula: Pt.sub.y WO.sub.3 where y is at least 0.8.

  1. Fuel cell oxygen electrode

    DOEpatents

    Shanks, H.R.; Bevolo, A.J.; Danielson, G.C.; Weber, M.F.

    An oxygen electrode for a fuel cell utilizing an acid electrolyte has a substrate of an alkali metal tungsten bronze of the formula: A/sub x/WO/sub 3/ where A is an alkali metal and x is at least 0.2, which is covered with a thin layer of platinum tungsten bronze of the formula: Pt/sub y/WO/sub 3/ where y is at least 0.8.

  2. Timescales of Oxygenation Following the Evolution of Oxygenic Photosynthesis

    NASA Astrophysics Data System (ADS)

    Ward, Lewis M.; Kirschvink, Joseph L.; Fischer, Woodward W.

    2016-03-01

    Among the most important bioenergetic innovations in the history of life was the invention of oxygenic photosynthesis—autotrophic growth by splitting water with sunlight—by Cyanobacteria. It is widely accepted that the invention of oxygenic photosynthesis ultimately resulted in the rise of oxygen by ca. 2.35 Gya, but it is debated whether this occurred more or less immediately as a proximal result of the evolution of oxygenic Cyanobacteria or whether they originated several hundred million to more than one billion years earlier in Earth history. The latter hypothesis involves a prolonged period during which oxygen production rates were insufficient to oxidize the atmosphere, potentially due to redox buffering by reduced species such as higher concentrations of ferrous iron in seawater. To examine the characteristic timescales for environmental oxygenation following the evolution of oxygenic photosynthesis, we applied a simple mathematical approach that captures many of the salient features of the major biogeochemical fluxes and reservoirs present in Archean and early Paleoproterozoic surface environments. Calculations illustrate that oxygenation would have overwhelmed redox buffers within ~100 kyr following the emergence of oxygenic photosynthesis, a geologically short amount of time unless rates of primary production were far lower than commonly expected. Fundamentally, this result arises because of the multiscale nature of the carbon and oxygen cycles: rates of gross primary production are orders of magnitude too fast for oxygen to be masked by Earth's geological buffers, and can only be effectively matched by respiration at non-negligible O2 concentrations. These results suggest that oxygenic photosynthesis arose shortly before the rise of oxygen, not hundreds of millions of years before it.

  3. Timescales of Oxygenation Following the Evolution of Oxygenic Photosynthesis.

    PubMed

    Ward, Lewis M; Kirschvink, Joseph L; Fischer, Woodward W

    2016-03-01

    Among the most important bioenergetic innovations in the history of life was the invention of oxygenic photosynthesis-autotrophic growth by splitting water with sunlight-by Cyanobacteria. It is widely accepted that the invention of oxygenic photosynthesis ultimately resulted in the rise of oxygen by ca. 2.35 Gya, but it is debated whether this occurred more or less immediately as a proximal result of the evolution of oxygenic Cyanobacteria or whether they originated several hundred million to more than one billion years earlier in Earth history. The latter hypothesis involves a prolonged period during which oxygen production rates were insufficient to oxidize the atmosphere, potentially due to redox buffering by reduced species such as higher concentrations of ferrous iron in seawater. To examine the characteristic timescales for environmental oxygenation following the evolution of oxygenic photosynthesis, we applied a simple mathematical approach that captures many of the salient features of the major biogeochemical fluxes and reservoirs present in Archean and early Paleoproterozoic surface environments. Calculations illustrate that oxygenation would have overwhelmed redox buffers within ~100 kyr following the emergence of oxygenic photosynthesis, a geologically short amount of time unless rates of primary production were far lower than commonly expected. Fundamentally, this result arises because of the multiscale nature of the carbon and oxygen cycles: rates of gross primary production are orders of magnitude too fast for oxygen to be masked by Earth's geological buffers, and can only be effectively matched by respiration at non-negligible O2 concentrations. These results suggest that oxygenic photosynthesis arose shortly before the rise of oxygen, not hundreds of millions of years before it. PMID:26286084

  4. Hydrogen film cooling of a small hydrogen-oxygen thrust chamber and its effect on erosion rates of various ablative materials

    NASA Technical Reports Server (NTRS)

    Hannum, N.; Roberts, W. E.; Russell, L. M.

    1977-01-01

    An experimental investigation was conducted to determine what arrangement of film-coolant-injection orifices should be used to decrease the erosion rates of small, high temperature, high pressure ablative thrust chambers without incurring a large penalty in combustion performance. All of the film cooling was supplied through holes in a ring between the outer row of injector elements and the chamber wall. The best arrangement, which had twice the number of holes as there were outer row injection elements, was also the simplest. The performance penalties, presented as a reduction in characteristic exhaust velocity efficiency, were 0.8 and 2.8 percentage points for the 10 and 20 percent cooling flows, respectively, The best film-coolant injector was then used to obtain erosion rates for 19 ablative materials. The throat erosion rate was reduced by a factor of 2.5 with a 10 percent coolant flow. Only the more expensive silica phenolic materials had low enough erosion rates to be considered for use in the nozzle throat. However, some of the cheaper materials might qualify for use in other areas of small nozzles with large throat diameters where the higher erosion rates are more acceptable.

  5. Effect of additive oxygen gas on cellular response of lung cancer cells induced by atmospheric pressure helium plasma jet.

    PubMed

    Joh, Hea Min; Choi, Ji Ye; Kim, Sun Ja; Chung, T H; Kang, Tae-Hong

    2014-01-01

    The atmospheric pressure helium plasma jet driven by pulsed dc voltage was utilized to treat human lung cancer cells in vitro. The properties of plasma plume were adjusted by the injection type and flow rate of additive oxygen gas in atmospheric pressure helium plasma jet. The plasma characteristics such as plume length, electric current and optical emission spectra (OES) were measured at different flow rates of additive oxygen to helium. The plasma plume length and total current decreased with an increase in the additive oxygen flow rate. The electron excitation temperature estimated by the Boltzmann plot from several excited helium emission lines increased slightly with the additive oxygen flow. The oxygen atom density in the gas phase estimated by actinometry utilizing argon was observed to increase with the additive oxygen flow. The concentration of intracellular reactive oxygen species (ROS) measured by fluorescence assay was found to be not exactly proportional to that of extracellular ROS (measured by OES), but both correlated considerably. It was also observed that the expression levels of p53 and the phospho-p53 were enhanced in the presence of additive oxygen flow compared with those from the pure helium plasma treatment. PMID:25319447

  6. Effect of additive oxygen gas on cellular response of lung cancer cells induced by atmospheric pressure helium plasma jet

    NASA Astrophysics Data System (ADS)

    Joh, Hea Min; Choi, Ji Ye; Kim, Sun Ja; Chung, T. H.; Kang, Tae-Hong

    2014-10-01

    The atmospheric pressure helium plasma jet driven by pulsed dc voltage was utilized to treat human lung cancer cells in vitro. The properties of plasma plume were adjusted by the injection type and flow rate of additive oxygen gas in atmospheric pressure helium plasma jet. The plasma characteristics such as plume length, electric current and optical emission spectra (OES) were measured at different flow rates of additive oxygen to helium. The plasma plume length and total current decreased with an increase in the additive oxygen flow rate. The electron excitation temperature estimated by the Boltzmann plot from several excited helium emission lines increased slightly with the additive oxygen flow. The oxygen atom density in the gas phase estimated by actinometry utilizing argon was observed to increase with the additive oxygen flow. The concentration of intracellular reactive oxygen species (ROS) measured by fluorescence assay was found to be not exactly proportional to that of extracellular ROS (measured by OES), but both correlated considerably. It was also observed that the expression levels of p53 and the phospho-p53 were enhanced in the presence of additive oxygen flow compared with those from the pure helium plasma treatment.

  7. Effect of additive oxygen gas on cellular response of lung cancer cells induced by atmospheric pressure helium plasma jet

    PubMed Central

    Joh, Hea Min; Choi, Ji Ye; Kim, Sun Ja; Chung, T. H.; Kang, Tae-Hong

    2014-01-01

    The atmospheric pressure helium plasma jet driven by pulsed dc voltage was utilized to treat human lung cancer cells in vitro. The properties of plasma plume were adjusted by the injection type and flow rate of additive oxygen gas in atmospheric pressure helium plasma jet. The plasma characteristics such as plume length, electric current and optical emission spectra (OES) were measured at different flow rates of additive oxygen to helium. The plasma plume length and total current decreased with an increase in the additive oxygen flow rate. The electron excitation temperature estimated by the Boltzmann plot from several excited helium emission lines increased slightly with the additive oxygen flow. The oxygen atom density in the gas phase estimated by actinometry utilizing argon was observed to increase with the additive oxygen flow. The concentration of intracellular reactive oxygen species (ROS) measured by fluorescence assay was found to be not exactly proportional to that of extracellular ROS (measured by OES), but both correlated considerably. It was also observed that the expression levels of p53 and the phospho-p53 were enhanced in the presence of additive oxygen flow compared with those from the pure helium plasma treatment. PMID:25319447

  8. Induction of microcin B17 formation in Escherichia coli ZK650 by limitation of oxygen and glucose is independent of glucose consumption rate

    NASA Technical Reports Server (NTRS)

    Gao, Q.; Fang, A.; Demain, A. L.

    2001-01-01

    We examined the consumption of glucose from the media in which Escherichia coli ZK650 was grown. This organism, which produces the polypeptide antibiotic microcin B17 best under conditions of limiting supplies of glucose and air, was grown with a low level of glucose (0.5 mg/ml) as well as a high level (5.0 mg/ml) under both high and low aeration. Glucose consumption rates were virtually identical under both high and low aeration. Thus, glucose consumption rate is not a regulating factor in microcin B17 formation.

  9. Microbial community and population dynamics of single-stage autotrophic nitrogen removal for dilute wastewater at the benchmark oxygen rate supply.

    PubMed

    Huang, Yu-Tzu; Chen, Shiou-Shiou; Lee, Po-Heng; Bae, Jaeho

    2013-11-01

    Microbial communities and their kinetic performance in a single-stage autotrophic nitrogen-removal filter at an optimal oxygen supply were examined to determine the presence and activity of denitrifiers, anaerobic ammonia-oxidizing (anammox), ammonia-oxidizing, and nitrite-oxidizing bacteria. To this end, different molecular biology techniques such as real-time quantitative polymerase chain reaction (qPCR) and biomarkers such as 16S rRNA revealed a diverse microbial community along the filter. It was important to survey the specific species of anammox bacteria using a newly designed Candidatus Brocadiafulgida (BF) specific primer, as well as Candidatus Brocadia anammoxidans (BA) and Candidatus Kuenenia stuttgartiensis (KS) specific primers. An unexpected finding was that the predominant anammox species switched from KS in concentrated wastewater to BA in dilute wastewaters. The Eckenfelder model of the NH3-N transformation along the filter was Se=S0 exp(-0.192D/L(2.3217)). These results provide a foundational understanding of the microbial structure and reaction kinetics in such systems. PMID:24011603

  10. Oxygen in demand: How oxygen has shaped vertebrate physiology.

    PubMed

    Dzal, Yvonne A; Jenkin, Sarah E M; Lague, Sabine L; Reichert, Michelle N; York, Julia M; Pamenter, Matthew E

    2015-08-01

    In response to varying environmental and physiological challenges, vertebrates have evolved complex and often overlapping systems. These systems detect changes in environmental oxygen availability and respond by increasing oxygen supply to the tissues and/or by decreasing oxygen demand at the cellular level. This suite of responses is termed the oxygen transport cascade and is comprised of several components. These components include 1) chemosensory detectors that sense changes in oxygen, carbon dioxide, and pH in the blood, and initiate changes in 2) ventilation and 3) cardiac work, thereby altering the rate of oxygen delivery to, and carbon dioxide clearance from, the tissues. In addition, changes in 4) cellular and systemic metabolism alters tissue-level metabolic demand. Thus the need for oxygen can be managed locally when increasing oxygen supply is not sufficient or possible. Together, these mechanisms provide a spectrum of responses that facilitate the maintenance of systemic oxygen homeostasis in the face of environmental hypoxia or physiological oxygen depletion (i.e. due to exercise or disease). Bill Milsom has dedicated his career to the study of these responses across phylogenies, repeatedly demonstrating the power of applying the comparative approach to physiological questions. The focus of this review is to discuss the anatomy, signalling pathways, and mechanics of each step of the oxygen transport cascade from the perspective of a Milsomite. That is, by taking into account the developmental, physiological, and evolutionary components of questions related to oxygen transport. We also highlight examples of some of the remarkable species that have captured Bill's attention through their unique adaptations in multiple components of the oxygen transport cascade, which allow them to achieve astounding physiological feats. Bill's research examining the oxygen transport cascade has provided important insight and leadership to the study of the diverse suite

  11. Simplified Two-Time Step Method for Calculating Combustion Rates and Nitrogen Oxide Emissions for Hydrogen/Air and Hydorgen/Oxygen

    NASA Technical Reports Server (NTRS)

    Molnar, Melissa; Marek, C. John

    2005-01-01

    A simplified single rate expression for hydrogen combustion and nitrogen oxide production was developed. Detailed kinetics are predicted for the chemical kinetic times using the complete chemical mechanism over the entire operating space. These times are then correlated to the reactor conditions using an exponential fit. Simple first order reaction expressions are then used to find the conversion in the reactor. The method uses a two-time step kinetic scheme. The first time averaged step is used at the initial times with smaller water concentrations. This gives the average chemical kinetic time as a function of initial overall fuel air ratio, temperature, and pressure. The second instantaneous step is used at higher water concentrations (> 1 x 10(exp -20) moles/cc) in the mixture which gives the chemical kinetic time as a function of the instantaneous fuel and water mole concentrations, pressure and temperature (T4). The simple correlations are then compared to the turbulent mixing times to determine the limiting properties of the reaction. The NASA Glenn GLSENS kinetics code calculates the reaction rates and rate constants for each species in a kinetic scheme for finite kinetic rates. These reaction rates are used to calculate the necessary chemical kinetic times. This time is regressed over the complete initial conditions using the Excel regression routine. Chemical kinetic time equations for H2 and NOx are obtained for H2/air fuel and for the H2/O2. A similar correlation is also developed using data from NASA s Chemical Equilibrium Applications (CEA) code to determine the equilibrium temperature (T4) as a function of overall fuel/air ratio, pressure and initial temperature (T3). High values of the regression coefficient R2 are obtained.

  12. Summary of Simplified Two Time Step Method for Calculating Combustion Rates and Nitrogen Oxide Emissions for Hydrogen/Air and Hydrogen/Oxygen

    NASA Technical Reports Server (NTRS)

    Marek, C. John; Molnar, Melissa

    2005-01-01

    A simplified single rate expression for hydrogen combustion and nitrogen oxide production was developed. Detailed kinetics are predicted for the chemical kinetic times using the complete chemical mechanism over the entire operating space. These times are then correlated to the reactor conditions using an exponential fit. Simple first order reaction expressions are then used to find the conversion in the reactor. The method uses a two time step kinetic scheme. The first time averaged step is used at the initial times with smaller water concentrations. This gives the average chemical kinetic time as a function of initial overall fuel air ratio, temperature, and pressure. The second instantaneous step is used at higher water concentrations (greater than l x 10(exp -20)) moles per cc) in the mixture which gives the chemical kinetic time as a function of the instantaneous fuel and water mole concentrations, pressure and temperature (T(sub 4)). The simple correlations are then compared to the turbulent mixing times to determine the limiting properties of the reaction. The NASA Glenn GLSENS kinetics code calculates the reaction rates and rate constants for each species in a kinetic scheme for finite kinetic rates. These reaction rates are used to calculate the necessary chemical kinetic times. This time is regressed over the complete initial conditions using the Excel regression routine. Chemical kinetic time equations for H2 and NOx are obtained for H2/Air fuel and for H2/O2. A similar correlation is also developed using data from NASA's Chemical Equilibrium Applications (CEA) code to determine the equilibrium temperature (T(sub 4)) as a function of overall fuel/air ratio, pressure and initial temperature (T(sub 3)). High values of the regression coefficient R squared are obtained.

  13. Cavitating Jet Method and System for Oxygenation of Liquids

    NASA Technical Reports Server (NTRS)

    Chahine, Georges L.

    2012-01-01

    Reclamation and re-use of water is critical for space-based life support systems. A number of functions must be performed by any such system including removal of various contaminants and oxygenation. For long-duration space missions, this must be done with a compact, reliable system that requires little or no use of expendables and minimal power. DynaJets cavitating jets can oxidize selected organic compounds with much greater energy efficiency than ultrasonic devices typically used in sonochemistry. The focus of this work was to develop cavitating jets to simultaneously accomplish the functions of oxygenation and removal of contaminants of importance to space-structured water reclamation systems. The innovation is a method to increase the concentration of dissolved oxygen or other gasses in a liquid. It utilizes a particular form of novel cavitating jet operating at low to moderate pressures to achieve a high-efficiency means of transporting and mixing the gas into the liquid. When such a jet is utilized to simultaneously oxygenate the liquid and to oxidize organic compounds within the liquid, such as those in waste water, the rates of contaminant removal are increased. The invention is directed toward an increase in the dissolved gas content of a liquid, in general, and the dissolved oxygen content of a liquid in particular.

  14. Changes in oxygen consumption induced by t-butyl hydroperoxide in perfused rat liver. Effect of free-radical scavengers.

    PubMed Central

    Videla, L A; Villena, M I; Donoso, G; Giulivi, C; Boveris, A

    1984-01-01

    The addition of t-butyl hydroperoxide to perfused rat liver elicited a biphasic effect on hepatic respiration. A rapid fall in liver oxygen consumption was initially observed, followed by a recovery phase leading to respiratory rates higher than the initial steady-state values of oxygen uptake. This overshoot in hepatic oxygen uptake was abolished by free-radical scavengers such as (+)-cyanidanol-3 or butylated hydroxyanisole at concentrations that did not alter mitochondrial respiration. (+)-Cyanidanol-3 was also able to facilitate the recovery of respiration, the diminution in the calculated rate of hydroperoxide utilization and the decrease in liver GSH content produced by two consecutive pulses of t-butyl hydroperoxide. It is suggested that the t-butyl hydroperoxide-induced overshoot in liver respiration is related to increased utilization of oxygen for lipid peroxidation as a consequence of free radicals produced in the scission of the hydroperoxide by cellular haemoproteins. PMID:6508746

  15. The mechanism by which oxygen and cytochrome c increase the rate of electron transfer from cytochrome a to cytochrome a3 of cytochrome c oxidase.

    PubMed

    Bickar, D; Turrens, J F; Lehninger, A L

    1986-11-01

    When cytochrome c oxidase is isolated from mitochondria, the purified enzyme requires both cytochrome c and O2 to achieve its maximum rate of internal electron transfer from cytochrome a to cytochrome a3. When reductants other than cytochrome c are used, the rate of internal electron transfer is very slow. In this paper we offer an explanation for the slow reduction of cytochrome a3 when reductants other than cytochrome c are used and for the apparent allosteric effects of cytochrome c and O2. Our model is based on the conventional understanding of cytochrome oxidase mechanism (i.e. electron transfer from cytochrome a/CuA to cytochrome a3/CuB), but assumes a relatively rapid two-electron transfer between cytochrome a/CuA and cytochrome a3/CuB and a thermodynamic equilibrium in the "resting" enzyme (the enzyme as isolated) which favors reduced cytochrome a and oxidized cytochrome a3. Using the kinetic constants that are known for this reaction, we find that the activating effects of O2 and cytochrome c on the rate of electron transfer from cytochrome a to cytochrome a3 conform to the predictions of the model and so provide no evidence of any allosteric effects or control of cytochrome c oxidase by O2 or cytochrome c. PMID:3021740

  16. Utility of a Novel Biofeedback Device for Within-Breath Modulation of Heart Rate in Rats: A Quantitative Comparison of Vagus Nerve vs. Right Atrial Pacing.

    PubMed

    O'Callaghan, Erin L; Chauhan, Ashok S; Zhao, Le; Lataro, Renata M; Salgado, Helio C; Nogaret, Alain; Paton, Julian F R

    2016-01-01

    In an emerging bioelectronics era, there is a clinical need for physiological devices incorporating biofeedback that permits natural and demand-dependent control in real time. Here, we describe a novel device termed a central pattern generator (CPG) that uses cutting edge analog circuitry producing temporally controlled, electrical stimulus outputs based on the real time integration of physiological feedback. Motivated by the fact that respiratory sinus arrhythmia (RSA), which is the cyclical changes in heart rate every breath, is an essential component of heart rate variability (HRV) (an indicator of cardiac health), we have explored the versatility and efficiency of the CPG for producing respiratory modulation of heart rate in anesthetized, spontaneously breathing rats. Diaphragmatic electromyographic activity was used as the input to the device and its output connected to either the right cervical vagus nerve or the right atrium for pacing heart rate. We found that the CPG could induce respiratory related heart rate modulation that closely mimicked RSA. Whether connected to the vagus nerve or right atrium, the versatility of the device was demonstrated by permitting: (i) heart rate modulation in any phase of the respiratory cycle, (ii) control of the magnitude of heart rate modulation, and (iii) instant adaptation to changes in respiratory frequency. Vagal nerve pacing was only possible following transection of the nerve limiting its effective use chronically. Pacing via the right atrium permitted better flexibility and control of heart rate above its intrinsic level. This investigation now lays the foundation for future studies using this biofeedback technology permitting closer analysis of both the function and dysfunction of RSA. PMID:26869940

  17. Utility of a Novel Biofeedback Device for Within-Breath Modulation of Heart Rate in Rats: A Quantitative Comparison of Vagus Nerve vs. Right Atrial Pacing

    PubMed Central

    O'Callaghan, Erin L.; Chauhan, Ashok S.; Zhao, Le; Lataro, Renata M.; Salgado, Helio C.; Nogaret, Alain; Paton, Julian F. R.

    2016-01-01

    In an emerging bioelectronics era, there is a clinical need for physiological devices incorporating biofeedback that permits natural and demand-dependent control in real time. Here, we describe a novel device termed a central pattern generator (CPG) that uses cutting edge analog circuitry producing temporally controlled, electrical stimulus outputs based on the real time integration of physiological feedback. Motivated by the fact that respiratory sinus arrhythmia (RSA), which is the cyclical changes in heart rate every breath, is an essential component of heart rate variability (HRV) (an indicator of cardiac health), we have explored the versatility and efficiency of the CPG for producing respiratory modulation of heart rate in anesthetized, spontaneously breathing rats. Diaphragmatic electromyographic activity was used as the input to the device and its output connected to either the right cervical vagus nerve or the right atrium for pacing heart rate. We found that the CPG could induce respiratory related heart rate modulation that closely mimicked RSA. Whether connected to the vagus nerve or right atrium, the versatility of the device was demonstrated by permitting: (i) heart rate modulation in any phase of the respiratory cycle, (ii) control of the magnitude of heart rate modulation, and (iii) instant adaptation to changes in respiratory frequency. Vagal nerve pacing was only possible following transection of the nerve limiting its effective use chronically. Pacing via the right atrium permitted better flexibility and control of heart rate above its intrinsic level. This investigation now lays the foundation for future studies using this biofeedback technology permitting closer analysis of both the function and dysfunction of RSA. PMID:26869940

  18. Calcification rate and the stable carbon, oxygen, and nitrogen isotopes in the skeleton, host tissue, and zooxanthellae of bleached and recovering Hawaiian corals

    NASA Astrophysics Data System (ADS)

    Rodrigues, Lisa J.; Grottoli, Andréa G.

    2006-06-01

    We tested the effectiveness of stable isotopes as recorders of physiological changes that occur during coral bleaching and recovery. Montipora capitata and Porites compressa fragments were bleached in outdoor tanks with seawater temperature raised to 30 °C (treatment corals) for one month. Additional fragments were maintained at 27 °C in separate tanks (control corals). After one month, (0 months recovery), buoyant weight was measured and a subset of fragments was frozen. Remaining fragments were returned to the reef for recovery. After 1.5, 4, and 8 months, fragments were collected, measured for buoyant weight, and frozen. Fragments were analyzed for stable carbon and oxygen isotopic compositions of the skeleton (δ 13C s; δ 18O s) and nitrogen and carbon isotopic compositions of the host tissue (δ 15N h; δ 13C h) and zooxanthellae (δ 15N z; δ 13C z). δ 13C s decreased immediately after bleaching in M. capitata, but not in P. compressa. δ 18O s of both species failed to record the warming event. During the remaining months of recovery, δ 13C s and δ 18O s were more enriched in treatment than control corals due to decreases in calcification and metabolic fractionation during that time. Increased δ 15N h of treatment P. compressa may be due to expelled zooxanthellae during bleaching and recovery. Increased δ 15N z at 1.5 months in treatment fragments of both species reflects the increased incorporation of dissolved inorganic nitrogen to facilitate mitotic cell division and/or chl a/cell recovery. Changes in δ 13C h and δ 13C z at 1.5 months in treatment M. capitata indicated a large increase in heterotrophically acquired carbon relative to photosynthetically fixed carbon. We experimentally show that isotopes in coral skeleton, host tissue and zooxanthellae can be used to verify physiological changes during bleaching and recovery, but their use as a proxy for past bleaching events in the skeletal record is limited.

  19. The influence of fuel mass load, oxygen supply and burning rate on emission factor and size distribution of carbonaceous particulate matter from indoor corn straw burning

    PubMed Central

    Shen, Guofeng; Xue, Miao; Wei, Siye; Chen, Yuanchen; Wang, Bing; Wang, Rong; Shen, Huizhong; Li, Wei; Zhang, Yanyan; Huang, Ye; Chen, Han; Wei, Wen; Zhao, Qiuyue; Li, Bin; Wu, Haisuo; Tao, Shu

    2014-01-01

    The uncertainty in emission estimation is strongly associated with the variation in emission factor which could be influenced by a variety of factors, like fuel property, stove type, fire management and even methods used in measurements. The impacts of these factors were usually complicated and often interacted with each other. In the present study, controlled burning experiments were conducted to investigate the influence of fuel mass load, air supply and burning rate on the emission of carbonaceous particulate matter (PM) from indoor corn straw burning. Their impacts on PM size distribution were also studied. The results showed that EFs of PM (EFPM), organic carbon (EFOC) and element carbon (EFEC) was independent of the fuel mass load. The differences among them under different burning rates or air supply amounts were also found to be insignificant (p > 0.05) in the tested circumstances. PM from the indoor corn straw burning was dominated by fine PM, and PM with diameter less than 2.1 μm contributed about 86.4±3.9% of the total. The size distribution of PM was also influenced by the burning rate and changed air supply conditions. On average, EFPM, EFOC and EFEC for corn straw burned in a residential cooking stove were 3.84±1.02, 0.846±0.895 and 0.391±0.350 g/kg, respectively. EFPM, EFOC and EFEC were found to be positively correlated with each other, but they were not significantly correlated with EF of co-emitted CO, suggesting a special attention should be paid to the use of CO acting as a surrogate for other incomplete pollutants. PMID:23923424

  20. Sounding of the Atmosphere using Broadband Emission Radiometry observations of daytime mesospheric O2(1Δ) 1.27 μm emission and derivation of ozone, atomic oxygen, and solar and chemical energy deposition rates

    NASA Astrophysics Data System (ADS)

    Mlynczak, Martin G.; Marshall, B. Thomas; Martin-Torres, F. Javier; Russell, James M.; Thompson, R. Earl; Remsberg, Ellis E.; Gordley, Larry L.

    2007-08-01

    We report observations of the daytime O2(1Δ) airglow emission at 1.27 μm recorded by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the NASA Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) satellite. The measured limb radiances are inverted to yield vertical profiles of the volume emission rate of energy from the O2 molecule. From these emission rates we subsequently derive the mesospheric ozone concentrations using a nonlocal thermodynamic equilibrium (non-LTE) radiative and kinetic model. Rates of energy deposition due to absorption of ultraviolet radiation in the Hartley band of ozone are also derived, independent of knowledge of the ozone abundance and solar irradiances. Atomic oxygen concentrations are obtained from the ozone abundance using photochemical steady state assumptions. Rates of energy deposition due to exothermic chemical reactions are also derived. The data products illustrated here are from a test day (4 July 2002) of SABER Version 1.07 data which are now becoming publicly available. This test day illustrates the high quality of the SABER O2(1Δ) airglow and ozone data and the variety of fundamental science questions to which they can be applied.