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Sample records for 5-day biological oxygen

  1. Assessment of knowledge of participants on basic molecular biology techniques after 5-day intensive molecular biology training workshops in Nigeria.

    PubMed

    Yisau, J I; Adagbada, A O; Bamidele, T; Fowora, M; Brai, B I C; Adebesin, O; Bamidele, M; Fesobi, T; Nwaokorie, F O; Ajayi, A; Smith, S I

    2017-02-01

    The deployment of molecular biology techniques for diagnosis and research in Nigeria is faced with a number of challenges, including the cost of equipment and reagents coupled with the dearth of personnel skilled in the procedures and handling of equipment. Short molecular biology training workshops were conducted at the Nigerian Institute of Medical Research (NIMR), to improve the knowledge and skills of laboratory personnel and academics in health, research, and educational facilities. Five-day molecular biology workshops were conducted annually between 2011 and 2014, with participants drawn from health, research facilities, and the academia. The courses consisted of theoretical and practical sessions. The impact of the workshops on knowledge and skill acquisition was evaluated by pre- and post-tests which consisted of 25 multiple choice and other questions. Sixty-five participants took part in the workshops. The mean knowledge of molecular biology as evaluated by the pre- and post-test assessments were 8.4 (95% CI 7.6-9.1) and 13.0 (95 CI 11.9-14.1), respectively. The mean post-test score was significantly greater than the mean pre-test score (p < 0.0001). The five-day molecular biology workshop significantly increased the knowledge and skills of participants in molecular biology techniques. © 2017 by The International Union of Biochemistry and Molecular Biology, 2017.

  2. Oxygen and Biological Evolution.

    ERIC Educational Resources Information Center

    Baugh, Mark A.

    1990-01-01

    Discussed is the evolution of aerobic organisms from anaerobic organisms and the accompanying biochemistry that developed to motivate and enable this evolution. Uses of oxygen by aerobic organisms are described. (CW)

  3. Singlet molecular oxygen generated by biological hydroperoxides.

    PubMed

    Miyamoto, Sayuri; Martinez, Glaucia R; Medeiros, Marisa H G; Di Mascio, Paolo

    2014-10-05

    The chemistry behind the phenomenon of ultra-weak photon emission has been subject of considerable interest for decades. Great progress has been made on the understanding of the chemical generation of electronically excited states that are involved in these processes. Proposed mechanisms implicated the production of excited carbonyl species and singlet molecular oxygen in the mechanism of generation of chemiluminescence in biological system. In particular, attention has been focused on the potential generation of singlet molecular oxygen in the recombination reaction of peroxyl radicals by the Russell mechanism. In the last ten years, our group has demonstrated the generation of singlet molecular oxygen from reactions involving the decomposition of biologically relevant hydroperoxides, especially from lipid hydroperoxides in the presence of metal ions, peroxynitrite, HOCl and cytochrome c. In this review we will discuss details on the chemical aspects related to the mechanism of singlet molecular oxygen generation from different biological hydroperoxides.

  4. Your Child's Development: 3-5 Days

    MedlinePlus

    ... Feeding Your 1- to 2-Year-Old Your Child’s Development: 3-5 Days KidsHealth > For Parents > Your Child’s Development: 3-5 Days A A A Though only ... the sole of the foot Social and Emotional Development soothed by a ... When to Talk to Your Doctor Every child develops at his or her own pace, but ...

  5. Your Child's Development: 3-5 Days

    MedlinePlus

    ... Feeding Your 1- to 2-Year-Old Your Child’s Development: 3-5 Days KidsHealth > For Parents > Your Child’s Development: 3-5 Days Print A A A en ... the sole of the foot Social and Emotional Development soothed by a ... When to Talk to Your Doctor Every child develops at his or her own pace, but ...

  6. Southern Ocean biological impacts on global ocean oxygen

    NASA Astrophysics Data System (ADS)

    Keller, David P.; Kriest, Iris; Koeve, Wolfgang; Oschlies, Andreas

    2016-06-01

    Southern Ocean (SO) physical and biological processes are known to have a large impact on global biogeochemistry. However, the role that SO biology plays in determining ocean oxygen concentrations is not completely understood. These dynamics are investigated here by shutting off SO biology in two marine biogeochemical models. The results suggest that SO biological processes reduce the ocean's oxygen content, mainly in the deep ocean, by 14 to 19%. However, since these processes also trap nutrients that would otherwise be transported northward to fuel productivity and subsequent organic matter export, consumption, and the accompanying oxygen consumption in midlatitude to low-latitude waters, SO biology helps to maintain higher oxygen concentrations in these subsurface waters. Thereby, SO biology can influence the size of the tropical oxygen minimum zones. As a result of ocean circulation the link between SO biological processes and remote oxygen changes operates on decadal to centennial time scales.

  7. Oxygen supersaturation in the ocean: biological versus physical contributions.

    PubMed

    Craig, H; Hayward, T

    1987-01-09

    A method based on measurements of dissolved molecular nitrogen, molecular oxygen, and argon can distingish biological from physical contributions to oxygen supersaturation in the ocean. The derived values of biological O(2) production can be used as a check on estimates of total organic productivity measured by instantaneous rates of carbon-14 assimilation. Application to the shallow summer O(2) maxima in the North Pacific gyres shows that about 72% of the O(2) supersaturation maximum at 28 degrees N and about 86% of the maximum at 40 degrees N are due to net photosynthetic production.

  8. Smart oxygen cuvette for optical monitoring of dissolved oxygen in biological blood samples

    NASA Astrophysics Data System (ADS)

    Dabhi, Harish; Alla, Suresh Kumar; Shahriari, Mahmoud R.

    2010-02-01

    A smart Oxygen Cuvette is developed by coating the inner surface of a cuvette with oxygen sensitive thin film material. The coating is glass like sol-gel based sensor that has an embedded ruthenium compound in the glass film. The fluorescence of the ruthenium is quenched depending on the oxygen level. Ocean Optics phase fluorometer, NeoFox is used to measure this rate of fluorescence quenching and computes it for the amount of oxygen present. Multimode optical fibers are used for transportation of light from an LED source to cuvette and from cuvette to phase fluorometer. This new oxygen sensing system yields an inexpensive solution for monitoring the dissolved oxygen in samples for biological and medical applications. In addition to desktop fluorometers, smart oxygen cuvettes can be used with the Ocean Optics handheld Fluorometers, NeoFox Sport. The Smart Oxygen Cuvettes provide a resolution of 4PPB units, an accuracy of less than 5% of the reading, and 90% response in less than 10 seconds.

  9. Removal of Biologically Active Organic Contaminants using Atomic Oxygen

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A. (Inventor); Banks, Michael A. (Inventor); Banks, Eric B. (Inventor)

    2003-01-01

    Biomedical devices that are to come into contact with living tissue, such as prosthetic and other implants for the human body and the containers used to store and transport them, are together cleaned of non-living, but biologically active organic materials, including endotoxins such as lipopolysaccharides, and assembled into a hermetically sealed package without recontamination. This is achieved by cleaning both the device and package components together in an apparatus, which includes a hermetically sealed chamber, in which they are contacted with atomic oxygen which biocleans them, by oxidizing the biologically active organic materials. The apparatus also includes means for manipulating the device and container and hermetically sealing the cleaned device into the cleaned container to form the package. A calibrated witness coupon visually indicates whether or not the device and container have received enough exposure to the atomic oxygen to have removed the organic materials from their surfaces. Gamma radiation is then used to sterilize the device in the sealed container.

  10. Implications of Oxygen Homeostasis for Tumor Biology and Treatment.

    PubMed

    Garvalov, Boyan K; Acker, Till

    2016-01-01

    Tumors serve as a prototype system to study the role of the hypoxic microenvironment and gain insight in the regulation oxygen homeostasis. A series of biochemical and cell biological studies have significantly extended our knowledge of how tumor cells activate key regulatory mechanisms of oxygen homeostasis not only to adapt to the hostile tumor microenvironment but also to acquire a more aggressive tumor phenotype. Reduced oxygen levels and tumor-specific genetic alterations synergistically drive tumor progression by activating a key transcriptional system, the hypoxia inducible factors (HIFs). HIFs trigger a set of adaptive responses commonly associated with tumor malignancy including tumor angiogenesis, a shift in metabolism, proliferation, invasion, and metastasis. We and others could demonstrate that cancer stem cells are controlled by HIFs within a hypoxic niche, establishing an intriguing link between the well known function of hypoxia in tumor growth and stem cell biology. Additionally, HIF activation potentially conveys resistance to current tumor therapies including the evasive resistance phenotype observed after anti-angiogenic treatment. Together, these findings provide strong evidence that activation of the HIF system is a decisive step in cancer progression that critically shapes therapy response and clinical outcome. Recent insight into the precise mechanisms of oxygen sensing and signalling has offered new promising and potentially selective strategies to counteract this crucial pathway.

  11. Studying Biological Responses to Global Change in Atmospheric Oxygen

    PubMed Central

    Powell, Frank L.

    2010-01-01

    A popular book recently hypothesized that change in atmospheric oxygen over geological time is the most important physical factor in the evolution of many fundamental characteristics of modern terrestrial animals. This hypothesis is generated primarily using fossil data but the present paper considers how modern experimental biology can be used to test it. Comparative physiology and experimental evolution clearly show that changes in atmospheric O2 over the ages had the potential to drive evolution, assuming the physiological O2-sensitivity of animals today is similar to the past. Established methods, such as phylogenetically independent contrasts, as well new approaches, such as adding environmental history to phylogenetic analyses or modeling interactions between environmental stresses and biological responses with different rate constants, may be useful for testing (disproving) hypotheses about biological adaptations to changes in atmospheric O2. PMID:20385257

  12. Artificial carrier for oxygen supply in biological systems.

    PubMed

    Dey, E S; Norrlöw, O; Liu, Y

    2004-04-01

    Several poly (dimethylsiloxanes) (PDMS) copolymers of dimethylsiloxane (DMS) with ethylene or propylene oxide were tested as artificial carriers for the delivery of oxygen to biological systems. Copolymers with a DMS content of 33% or lower enhanced glucose oxidation by 200% in contrast to the 25% increase produced by the same concentration of perfluorodecalin. When 0.05% of the copolymer with 18% DMS was included in the growth media of Bacillus thuriginensis, the biomass (growth rate) increased 1.5-fold. With 0.1% of this copolymer, actinorhodin production by Streptomyces coelicolor A3 (2) occurred in half the normal time and with an increased yield. In conclusion, these PDMS copolymers are a good alternative to perfluorodecalin as oxygen carriers in biotechnological processes.

  13. Biological Oxygen Productivity Over The Last Glacial Termination From Triple Oxygen Isotope Measurements

    NASA Astrophysics Data System (ADS)

    Blunier, T.; Bender, M. L.; Hendricks, M. B.

    The atmospheric oxygen isotope signature of O2 is linked to the oxygen signature of seawater through photosynthesis and respiration. Fractionation during these pro- cesses is mass dependent affecting 17O about half as much as 18O. A mass indepen- dent fractionation process takes place during isotope exchange between O2 and CO2 in the stratosphere (Thiemens, 1999; Luz et al., 1999). The magnitude of the mass- independent anomaly in the triple isotope composition of O2 depends on relative rates of biological O2 cycling and photochemical reactions in the stratosphere. Variations of this anomaly thus allows us to estimate changes of mass dependent O2 production by photosynthesis versus mass independent O2-CO2 exchange in the stratosphere. We reconstruct total oxygen productivity for the past from 17O and 18O measure- ments of O2 trapped in ice cores. With a box model we estimate that the total biogenic productivity was only 76-83 % of today for the glacial and was probably still lower than today during the glacial-interglacial transition and the early Holocene. In principle we can calculate the oxygen flux from the ocean biosphere if we know the oxygen flux from the land biosphere. Calculated ocean production is very sensitive to the estimate of land biosphere production. The latter term remains uncertain, however, and we can presently only constrain glacial ocean production to 88 to 140 % of the present value.

  14. Biological oxygen productivity during the last 60,000 years from triple oxygen isotope measurements

    NASA Astrophysics Data System (ADS)

    Blunier, Thomas; Barnett, Bruce; Bender, Michael L.; Hendricks, Melissa B.

    2002-07-01

    The oxygen isotope signature of atmospheric O2 is linked to the isotopic signature of seawater (H2O) through photosynthesis and respiration. Fractionation during these processes is mass dependent, affecting δ17O about half as much as δ18O. An ``anomalous'' fractionation process, which changes δ17O and δ18O of O2 about equally, takes place during isotope exchange between O2 and CO2 in the stratosphere. The relative rates of biologic O2 production and stratospheric processing determine the relationship between δ17O and δ18O of O2 in the atmosphere. Variations of this relationship thus allow us to estimate changes in the rate of mass-dependent O2 production by photosynthesis versus the rate of O2-CO2 exchange in the stratosphere with about equal fractionations of δ17O and δ18O. In this study we reconstruct total oxygen productivity for the last glacial, the last glacial termination, and the early Holocene from the triple isotope composition of atmospheric oxygen trapped in ice cores. With a box model we estimate that total biogenic productivity was only ~76-83% of today for the glacial and was probably lower than today during the glacial-interglacial transition and the early Holocene. Depending on how reduced the oxygen flux from the land biosphere was during the glacial, the oxygen flux from the glacial ocean biosphere was 88-140% of its present value.

  15. Biological nitrification process simulation in groundwater with dissolved oxygen controller

    NASA Astrophysics Data System (ADS)

    Zuo, Jinlong

    2009-07-01

    Nowadays groundwater contamination by nitrogenous fertilizer is a globally growing problem, but groundwater always serves as an important water source, especially in rural area. In order to tackle this problem, biological nitrification and denitrification process has been widely used for removal of nitrogenous pollutants from polluted water. To improve removal efficiency, the dissolved oxygen (DO) controller is presented. And the control strategies for the activated sludge process have been developed and evaluated by simulation. The results also showed that the DO controller will be applied widely in the control and management of the decentralization water treatment.

  16. NASA Animation Shows Hurricane Otto Over 5 Days

    NASA Video Gallery

    A 5-day movie of NOAA's GOES-East satellite infrared and visible imagery of Hurricane Otto was created by the NASA/NOAA GOES Project at NASA's Goddard Space Flight Center in Greenbelt, Maryland. Th...

  17. PHYSICAL AND BIOLOGICAL CONTROLS ON DISSOLVED OXYGEN DYNAMICS IN PENSACOLA BAY, FL

    EPA Science Inventory

    Nutrient enrichment of estuaries and coastal waters can contribute to hypoxia (low dissolved oxygen) by increasing primary production and biological oxygen demand. Other factors, however, contribute to hypoxia and affect the susceptibility of coastal waters to hypoxia. Hypoxia fo...

  18. Biological regulation of atmospheric chemistry en route to planetary oxygenation.

    PubMed

    Izon, Gareth; Zerkle, Aubrey L; Williford, Kenneth H; Farquhar, James; Poulton, Simon W; Claire, Mark W

    2017-03-28

    Emerging evidence suggests that atmospheric oxygen may have varied before rising irreversibly ∼2.4 billion years ago, during the Great Oxidation Event (GOE). Significantly, however, pre-GOE atmospheric aberrations toward more reducing conditions-featuring a methane-derived organic-haze-have recently been suggested, yet their occurrence, causes, and significance remain underexplored. To examine the role of haze formation in Earth's history, we targeted an episode of inferred haze development. Our redox-controlled (Fe-speciation) carbon- and sulfur-isotope record reveals sustained systematic stratigraphic covariance, precluding nonatmospheric explanations. Photochemical models corroborate this inference, showing Δ(36)S/Δ(33)S ratios are sensitive to the presence of haze. Exploiting existing age constraints, we estimate that organic haze developed rapidly, stabilizing within ∼0.3 ± 0.1 million years (Myr), and persisted for upward of ∼1.4 ± 0.4 Myr. Given these temporal constraints, and the elevated atmospheric CO2 concentrations in the Archean, the sustained methane fluxes necessary for haze formation can only be reconciled with a biological source. Correlative δ(13)COrg and total organic carbon measurements support the interpretation that atmospheric haze was a transient response of the biosphere to increased nutrient availability, with methane fluxes controlled by the relative availability of organic carbon and sulfate. Elevated atmospheric methane concentrations during haze episodes would have expedited planetary hydrogen loss, with a single episode of haze development providing up to 2.6-18 × 10(18) moles of O2 equivalents to the Earth system. Our findings suggest the Neoarchean likely represented a unique state of the Earth system where haze development played a pivotal role in planetary oxidation, hastening the contingent biological innovations that followed.

  19. Ocean oxygen minima expansions and their biological impacts

    NASA Astrophysics Data System (ADS)

    Stramma, Lothar; Schmidtko, Sunke; Levin, Lisa A.; Johnson, Gregory C.

    2010-04-01

    Climate models with biogeochemical components predict declines in oceanic dissolved oxygen with global warming. In coastal regimes oxygen deficits represent acute ecosystem perturbations. Here, we estimate dissolved oxygen differences across the global tropical and subtropical oceans within the oxygen minimum zone (200-700-dbar depth) between 1960-1974 (an early period with reliable data) and 1990-2008 (a recent period capturing ocean response to planetary warming). In most regions of the tropical Pacific, Atlantic, and Indian Oceans the oxygen content in the 200-700-dbar layer has declined. Furthermore, at 200 dbar, the area with O 2 <70 μmol kg -1, where some large mobile macro-organisms are unable to abide, has increased by 4.5 million km 2. The tropical low oxygen zones have expanded horizontally and vertically. Subsurface oxygen has decreased adjacent to most continental shelves. However, oxygen has increased in some regions in the subtropical gyres at the depths analyzed. According to literature discussed below, fishing pressure is strong in the open ocean, which may make it difficult to isolate the impact of declining oxygen on fisheries. At shallower depths we predict habitat compression will occur for hypoxia-intolerant taxa, with eventual loss of biodiversity. Should past trends in observed oxygen differences continue into the future, shifts in animal distributions and changes in ecosystem structure could accelerate.

  20. Rapid biologically mediated oxygen isotope exchange between water and phosphate

    NASA Astrophysics Data System (ADS)

    Paytan, Adina; Kolodny, Yehoshua; Neori, Amir; Luz, Boaz

    2002-03-01

    In order to better constrain the rate of oxygen isotope exchange between water and phosphate via biochemical reactions a set of controlled experiments were conducted in 1988 at the Aquaculture Plant in Elat, Israel. Different species of algae and other organisms were grown in seawater tanks under controlled conditions, and the water temperature and oxygen isotopic composition (δ18Ow) were monitored. The oxygen isotopic composition of phosphate (δ18Op) in the organisms' food source, tissues, and the δ18Op of dissolved inorganic phosphate (DIP) were measured at different stages of the experiments. Results indicate that intracellular oxygen isotope exchange between phosphorus compounds and water is very rapid and occurs at all levels of the food chain. Through these reactions the soft tissue δ18Op values become 23-26‰ higher than δ18Ow, and δ18Op values of DIP become ~20‰ higher than δ18Ow. No correlation between δ18Op values and either temperature or P concentrations in these experiments was observed. Our data imply that biogenic recycling and intracellular phosphorus turnover, which involves kinetic fractionation effects, are the major parameters controlling the δ18Op values of P compounds dissolved in aquatic systems. This information is fundamental to any application of δ18Op of dissolved organic or inorganic phosphate to quantify the dynamics of phosphorus cycling in aquatic systems.

  1. BIOMONITORING OF REACTIVE OXYGEN SPECIES IN BIOLOGICAL FLUIDS

    EPA Science Inventory

    Elevated levels of reactive oxygen species (ROS) are associated with several disease processes in humans, including cancer, asthma, diabetes, and cardiac disease. We have explored whether ROS can be measured directly in human fluids, and their value as a biomarker of exposure an...

  2. Combined phosphorescence-holographic approach for singlet oxygen detection in biological media

    NASA Astrophysics Data System (ADS)

    Semenova, I. V.; Belashov, A. V.; Beltukova, D. M.; Petrov, N. V.; Vasyutinskii, O. S.

    2015-06-01

    The paper presents a novel combined approach aimed to detect and monitor singlet oxygen molecules in biological specimens by means of the simultaneous recording and monitoring of their deactivation dynamics in the two complementary channels: radiative and nonradiative. The approach involves both the direct registration of phosphorescence at the wavelength of about 1270 nm caused by radiative relaxation of excited singlet oxygen molecules and holographic recording of thermal disturbances in the medium produced by their nonradiative relaxation. The data provides a complete set of information on singlet oxygen location and dynamics in the medium. The approach was validated in the case study of photosensitized generation of singlet oxygen in onion cell structures.

  3. Muonium response to oxygen content in biological aqueous solutions for cancer research

    NASA Astrophysics Data System (ADS)

    Pant, A. D.; Nagamine, K.; Shiraki, I.; Torikai, E.; Shimomura, K.; Pratt, F. L.; Ariga, H.; Ishida, K.; Schultz, J. S.

    2014-12-01

    Muonium (Mu), which is known to exhibit a characteristic concentration dependent spin relaxation change when impacting molecular oxygen dissolved in water, was found to show a similar behaviour in aqueous solutions of Tris Buffered Saline (TBS), albumin, serum, and hemoglobin (Hb). These effects, along with the interaction of Mu with deoxy-Hb (which is modulated by oxygen by the formation of oxy-Hb) suggest that the muon method can be applied to systematic studies of oxygen dependent effects in biological systems. This muon method may particularly be applicable at low (hypoxic) oxygen levels, an important consideration in the radiation treatment of cancer.

  4. Biological oxygen apparent transmissibility of hydrogel contact lenses with and without organosilicon moieties.

    PubMed

    Compañ, V; López-Alemany, A; Riande, E; Refojo, M F

    2004-01-01

    The instrument oxygen transmissibility (IOT) of organosilicon hydrogels, measured by electrochemical procedures, is 5-10 times larger than that of conventional hydrogels. A method is described that allows the estimation of the oxygen tension at the lens-cornea interface for closed- and open-eyelids situations by combining the IOT of the hydrogels and corneal parameters such as corneal thickness, corneal permeability and oxygen flux across the cornea. From these results the biological oxygen apparent transmissibility (BOAT) is obtained, an important parameter which an multiplication with the pressure of oxygen on the external part of the lens gives the oxygen flux onto the cornea. Contact lenses with oxygen transmissibility higher than 100 Dk/t units [1 Dk/t unit=10(-9) [cm(3) O(2) (STp) cm(-2)s(-1)(mmHg)(-1)] posses a large oxygen tension at the lens-cornea interface that substantially reduces the oxygen flux onto the cornea. Lenses whose oxygen transmissibility is lower than 50 Dk/t units allow a rather small oxygen flux onto the cornea under closed eyelids condition that prevent their use for extended wear.

  5. The Quantum Biology of Reactive Oxygen Species Partitioning Impacts Cellular Bioenergetics

    NASA Astrophysics Data System (ADS)

    Usselman, Robert J.; Chavarriaga, Cristina; Castello, Pablo R.; Procopio, Maria; Ritz, Thorsten; Dratz, Edward A.; Singel, David J.; Martino, Carlos F.

    2016-12-01

    Quantum biology is the study of quantum effects on biochemical mechanisms and biological function. We show that the biological production of reactive oxygen species (ROS) in live cells can be influenced by coherent electron spin dynamics, providing a new example of quantum biology in cellular regulation. ROS partitioning appears to be mediated during the activation of molecular oxygen (O2) by reduced flavoenzymes, forming spin-correlated radical pairs (RPs). We find that oscillating magnetic fields at Zeeman resonance alter relative yields of cellular superoxide (O2•‑) and hydrogen peroxide (H2O2) ROS products, indicating coherent singlet-triplet mixing at the point of ROS formation. Furthermore, the orientation-dependence of magnetic stimulation, which leads to specific changes in ROS levels, increases either mitochondrial respiration and glycolysis rates. Our results reveal quantum effects in live cell cultures that bridge atomic and cellular levels by connecting ROS partitioning to cellular bioenergetics.

  6. The Quantum Biology of Reactive Oxygen Species Partitioning Impacts Cellular Bioenergetics

    PubMed Central

    Usselman, Robert J.; Chavarriaga, Cristina; Castello, Pablo R.; Procopio, Maria; Ritz, Thorsten; Dratz, Edward A.; Singel, David J.; Martino, Carlos F.

    2016-01-01

    Quantum biology is the study of quantum effects on biochemical mechanisms and biological function. We show that the biological production of reactive oxygen species (ROS) in live cells can be influenced by coherent electron spin dynamics, providing a new example of quantum biology in cellular regulation. ROS partitioning appears to be mediated during the activation of molecular oxygen (O2) by reduced flavoenzymes, forming spin-correlated radical pairs (RPs). We find that oscillating magnetic fields at Zeeman resonance alter relative yields of cellular superoxide (O2•−) and hydrogen peroxide (H2O2) ROS products, indicating coherent singlet-triplet mixing at the point of ROS formation. Furthermore, the orientation-dependence of magnetic stimulation, which leads to specific changes in ROS levels, increases either mitochondrial respiration and glycolysis rates. Our results reveal quantum effects in live cell cultures that bridge atomic and cellular levels by connecting ROS partitioning to cellular bioenergetics. PMID:27995996

  7. [Visual-manual tracking during 5-day dry immersion].

    PubMed

    Kornilova, L N; Naumov, I A; Glukhikh, D O

    2011-01-01

    Level dry immersion (DI), a model of the physiological effects of microgravity, support deprivation, minimization of muscle activity and proprioceptive afferentation specifically, was used to determine the effects of low proprioceptive, tactile and support afferentation on visual-manual tracking. Hand-eye motor coordination was tested in 13 subjects in 5-d DI who tracked jerky and smooth (linear and pendulum-like horizontal and vertical, circular clockwise and counterclockwise) motions of point visual stimulus. Binocular electrooculography was used to register ocular movements and a joystick with a biological visual feedback to register manual motor acts (1 of 2 stimuli on the screen showed the actual joystick inclination). Computerized stimulation was provided with the help of virtual goggles. Evaluated parameters were latent and total reaction time, amplitude and velocity of eye and hand movements, coefficients of effectiveness (amplitudes ratio) and gain (velocity ratio). Testing was performed before DI, after 3 hours in DI, on DI days 3 and 5, during the first hours and in 3 days after DI (all subjects) and on post-DI days 5-7 (4 subjects). It was demonstrated that support deprivation and minimization of proprioceptive afferentation affect ocular tracking to a larger degree than accuracy of the manual motor act of following the visual stimulus. Manual tracking by all subjects was found more accurate than visual and did not alter significantly during tests sessions; on the contrary, visual tracking accuracy altered noticeably as in the course, so after DI.

  8. Functioning of the Ocean Biological Pump in the Oxygen Minimum Zones

    NASA Astrophysics Data System (ADS)

    Moore, J. K.

    2015-12-01

    Oxygen minimum zones occur at mid-depths in the water column in regions with weak ventilation and relatively high export of organic matter from surface waters. They are important ocean for ocean biogeochemistry, and potentially for climate, as sites of water column denitrification and nitrous oxide production. Denitrification is the dominant loss process for fixed nitrogen in the oceans, and can thus affect the ocean inventory of this key nutrient. Denitrification is less energetically efficient than oxic remineralization. Larger zooplankton, which feed on sinking particles, are not present in the lowest oxygen waters. Both of these factors suggest that the remineralization of sinking particles may be slower within the OMZs than in more oxygenated waters. There is limited field evidence and from some modeling studies that remineralization is slower (remineralization length scales are longer) within OMZ waters. In this talk, I will present results from the Community Earth System Model (CESM) ocean component attempting to test this hypothesis. Comparing model results with observed ocean biogeochemical tracer distributions (i.e., phosphate, oxygen), I will examine whether slower remineralization within low oxygen waters provides a better match between simulated and observed tracer distributions. Longer remineralization length scales under low oxygen conditions would provide a negative feedback under global warming scenarios. The biological pump would transfer organic materials to depth more efficiently as ocean oxygen concentrations decline and the OMZs expand.

  9. [Oxygen-limited autotrophic nitrification and denitrification--a novel technology for biological nitrogen removal].

    PubMed

    Zhang, Dan; Xu, Hui; Li, Xiangli; Zhang, Ying; Chen, Guanxiong

    2003-12-01

    Oxygen-limited autotrophic nitrification and denitrification (OLAND) is a biological nitrogen removal process coupled with partial nitrification and anaerobic ammonium oxidation. In our study, the nitrification was blocked at nitrite stage by controlling the dissolved oxygen concentration at 0.1-0.3 mg.L-1, and then, the denitrification proceeded, with the residual ammonium at the partial nitrification stage as electron donor. As a completely autotrophic nitrification-denitrification process, the OLAND was of many advantages (e.g., low energy consumption, high nitrogen removal rate and small footprint of system), and suitable in particular for treating low COD/NH4(+)-N ratio wastewater. It has become one of the most prosperous and practicable biological nitrogen removal technologies. The recent research of OLAND was reviewed, and its microbial mechanism as well as its applicable prospect was remarked in this paper.

  10. Total, chemical, and biological oxygen consumption of the sediments in the Ziya River watershed, China.

    PubMed

    Rong, Nan; Shan, Baoqing

    2016-07-01

    Sediment oxygen demand (SOD) is a critical dissolved oxygen (DO) sink in many rivers. Understanding the relative contributions of the biological and chemical components of SOD would improve our knowledge of the potential environmental harm SOD could cause and allow appropriate management systems to be developed. A various inhibitors addition technique was conducted to measure the total, chemical, and biological SOD of sediment samples from 13 sites in the Ziya River watershed, a severely polluted and anoxic river system in the north of China. The results showed that the major component of SOD was chemical SOD due to iron predominate. The ferrous SOD accounted for 21.6-78.9 % of the total SOD and 33.26-96.79 % of the chemical SOD. Biological SOD represented 41.13 % of the overall SOD averagely. Sulfide SOD accounted for 1.78-45.71 % of the total SOD and it was the secondary predominate of the chemical SOD. Manganous SOD accounted for 1.2-16.6 % of the total SOD and it was insignificant at many sites. Only four kinds of benthos were collected in the Ziya River watershed, resulting from the low DO concentration in the sediment surface due to SOD. This study would be helpful for understanding and preventing the potential sediment oxygen depletion during river restoration.

  11. Mechanism and stereoselectivity of biologically important oxygenation reactions of the 7-dehydrocholesterol radical.

    PubMed

    Rajeev, Ramanan; Sunoj, Raghavan B

    2013-07-19

    The mechanism of free radical oxygenation of 7-dehydrocholesterol (7-DHC), one of the biologically important sterols, is investigated by using density functional theory. The energetic origin of the product distribution and the stereoelectronic factors involved in various mechanistic pathways are delineated. The addition of triplet molecular oxygen to two types of conjugatively stabilized radicals, generated by the removal of the reactive allylic hydrogens from C9 or C14 positions, respectively denoted as H9 and H14 pathways, is studied. The distortion-interaction analysis of the C-O bond formation transition states suggests that the energetic preference toward the α prochiral face stems from reduced skeletal distortions of the cholesterol backbone as compared to that in the corresponding β prochiral face. This insight derived through a detailed quantitative analysis of the stereocontrolling transition states suggests that the commonly found interpretations solely based on steric interactions between the incoming oxygen and the protruding angular methyl groups (C10, C13 methyls) in the β face calls for adequate refinement. The relative energies of the transition states for molecular oxygen addition to C9, C5, and C14 (where spin densities are higher) and the ensuing products thereof are in agreement with the experimentally reported distribution of oxygenated 7-DHCs.

  12. Phosphate oxygen isotopic evidence for a temperate and biologically active Archaean ocean.

    PubMed

    Blake, Ruth E; Chang, Sae Jung; Lepland, Aivo

    2010-04-15

    Oxygen and silicon isotope compositions of cherts and studies of protein evolution have been interpreted to reflect ocean temperatures of 55-85 degrees C during the early Palaeoarchaean era ( approximately 3.5 billion years ago). A recent study combining oxygen and hydrogen isotope compositions of cherts, however, makes a case for Archaean ocean temperatures being no greater than 40 degrees C (ref. 5). Ocean temperature can also be assessed using the oxygen isotope composition of phosphate. Recent studies show that (18)O:(16)O ratios of dissolved inorganic phosphate (delta(18)O(P)) reflect ambient seawater temperature as well as biological processing that dominates marine phosphorus cycling at low temperature. All forms of life require and concentrate phosphorus, and as a result of biological processing, modern marine phosphates have delta(18)O(P) values typically between 19-26 per thousand (VSMOW), highly evolved from presumed source values of approximately 6-8 per thousand that are characteristic of apatite in igneous rocks and meteorites. Here we report oxygen isotope compositions of phosphates in sediments from the 3.2-3.5-billion-year-old Barberton Greenstone Belt in South Africa. We find that delta(18)O(P) values range from 9.3 per thousand to 19.9 per thousand and include the highest values reported for Archaean rocks. The temperatures calculated from our highest delta(18)O(P) values and assuming equilibrium with sea water with delta(18)O = 0 per thousand (ref. 12) range from 26 degrees C to 35 degrees C. The higher delta(18)O(P) values are similar to those of modern marine phosphate and suggest a well-developed phosphorus cycle and evolved biologic activity on the Archaean Earth.

  13. The role of biology in planetary evolution: cyanobacterial primary production in low-oxygen Proterozoic oceans.

    PubMed

    Hamilton, Trinity L; Bryant, Donald A; Macalady, Jennifer L

    2016-02-01

    Understanding the role of biology in planetary evolution remains an outstanding challenge to geobiologists. Progress towards unravelling this puzzle for Earth is hindered by the scarcity of well-preserved rocks from the Archean (4.0 to 2.5 Gyr ago) and Proterozoic (2.5 to 0.5 Gyr ago) Eons. In addition, the microscopic life that dominated Earth's biota for most of its history left a poor fossil record, consisting primarily of lithified microbial mats, rare microbial body fossils and membrane-derived hydrocarbon molecules that are still challenging to interpret. However, it is clear from the sulfur isotope record and other geochemical proxies that the production of oxygen or oxidizing power radically changed Earth's surface and atmosphere during the Proterozoic Eon, pushing it away from the more reducing conditions prevalent during the Archean. In addition to ancient rocks, our reconstruction of Earth's redox evolution is informed by our knowledge of biogeochemical cycles catalysed by extant biota. The emergence of oxygenic photosynthesis in ancient cyanobacteria represents one of the most impressive microbial innovations in Earth's history, and oxygenic photosynthesis is the largest source of O2 in the atmosphere today. Thus the study of microbial metabolisms and evolution provides an important link between extant biota and the clues from the geologic record. Here, we consider the physiology of cyanobacteria (the only microorganisms capable of oxygenic photosynthesis), their co-occurrence with anoxygenic phototrophs in a variety of environments and their persistence in low-oxygen environments, including in water columns as well as mats, throughout much of Earth's history. We examine insights gained from both the rock record and cyanobacteria presently living in early Earth analogue ecosystems and synthesize current knowledge of these ancient microbial mediators in planetary redox evolution. Our analysis supports the hypothesis that anoxygenic photosynthesis

  14. The role of biology in planetary evolution: cyanobacterial primary production in low‐oxygen Proterozoic oceans

    PubMed Central

    Bryant, Donald A.; Macalady, Jennifer L.

    2016-01-01

    Summary Understanding the role of biology in planetary evolution remains an outstanding challenge to geobiologists. Progress towards unravelling this puzzle for Earth is hindered by the scarcity of well‐preserved rocks from the Archean (4.0 to 2.5 Gyr ago) and Proterozoic (2.5 to 0.5 Gyr ago) Eons. In addition, the microscopic life that dominated Earth's biota for most of its history left a poor fossil record, consisting primarily of lithified microbial mats, rare microbial body fossils and membrane‐derived hydrocarbon molecules that are still challenging to interpret. However, it is clear from the sulfur isotope record and other geochemical proxies that the production of oxygen or oxidizing power radically changed Earth's surface and atmosphere during the Proterozoic Eon, pushing it away from the more reducing conditions prevalent during the Archean. In addition to ancient rocks, our reconstruction of Earth's redox evolution is informed by our knowledge of biogeochemical cycles catalysed by extant biota. The emergence of oxygenic photosynthesis in ancient cyanobacteria represents one of the most impressive microbial innovations in Earth's history, and oxygenic photosynthesis is the largest source of O 2 in the atmosphere today. Thus the study of microbial metabolisms and evolution provides an important link between extant biota and the clues from the geologic record. Here, we consider the physiology of cyanobacteria (the only microorganisms capable of oxygenic photosynthesis), their co‐occurrence with anoxygenic phototrophs in a variety of environments and their persistence in low‐oxygen environments, including in water columns as well as mats, throughout much of Earth's history. We examine insights gained from both the rock record and cyanobacteria presently living in early Earth analogue ecosystems and synthesize current knowledge of these ancient microbial mediators in planetary redox evolution. Our analysis supports the hypothesis that anoxygenic

  15. Looking beyond stratification: a model-based analysis of the biological drivers of oxygen deficiency in the North Sea

    NASA Astrophysics Data System (ADS)

    Große, Fabian; Greenwood, Naomi; Kreus, Markus; Lenhart, Hermann-Josef; Machoczek, Detlev; Pätsch, Johannes; Salt, Lesley; Thomas, Helmuth

    2016-04-01

    Low oxygen conditions, often referred to as oxygen deficiency, occur regularly in the North Sea, a temperate European shelf sea. Stratification represents a major process regulating the seasonal dynamics of bottom oxygen, yet, lowest oxygen conditions in the North Sea do not occur in the regions of strongest stratification. This suggests that stratification is an important prerequisite for oxygen deficiency, but that the complex interaction between hydrodynamics and the biological processes drives its evolution. In this study we use the ecosystem model HAMSOM-ECOHAM to provide a general characterisation of the different zones of the North Sea with respect to oxygen, and to quantify the impact of the different physical and biological factors driving the oxygen dynamics inside the entire sub-thermocline volume and directly above the bottom. With respect to oxygen dynamics, the North Sea can be subdivided into three different zones: (1) a highly productive, non-stratified coastal zone, (2) a productive, seasonally stratified zone with a small sub-thermocline volume, and (3) a productive, seasonally stratified zone with a large sub-thermocline volume. Type 2 reveals the highest susceptibility to oxygen deficiency due to sufficiently long stratification periods (> 60 days) accompanied by high surface productivity resulting in high biological consumption, and a small sub-thermocline volume implying both a small initial oxygen inventory and a strong influence of the biological consumption on the oxygen concentration. Year-to-year variations in the oxygen conditions are caused by variations in primary production, while spatial differences can be attributed to differences in stratification and water depth. The large sub-thermocline volume dominates the oxygen dynamics in the northern central and northern North Sea and makes this region insusceptible to oxygen deficiency. In the southern North Sea the strong tidal mixing inhibits the development of seasonal stratification

  16. Understanding the biological activity of high rate algae ponds through the calculation of oxygen balances.

    PubMed

    Arbib, Zouhayr; de Godos Crespo, Ignacio; Corona, Enrique Lara; Rogalla, Frank

    2017-03-24

    Microalgae culture in high rate algae ponds (HRAP) is an environmentally friendly technology for wastewater treatment. However, for the implementation of these systems, a better understanding of the oxygenation potential and the influence of climate conditions is required. In this work, the rates of oxygen production, consumption, and exchange with the atmosphere were calculated under varying conditions of solar irradiance and dilution rate during six months of operation in a real scale unit. This analysis allowed determining the biological response of these dynamic systems. The rates of oxygen consumption measured were considerably higher than the values calculated based on the organic loading rate. The response to light intensity in terms of oxygen production in the bioreactor was described with one of the models proposed for microalgae culture in dense concentrations. This model is based on the availability of light inside the culture and the specific response of microalgae to this parameter. The specific response to solar radiation intensity showed a reasonable stability in spite of the fluctuations due to meteorological conditions. The methodology developed is a useful tool for optimization and prediction of the performance of these systems.

  17. The Role of Reactive Oxygen Species (ROS) in the Biological Activities of Metallic Nanoparticles.

    PubMed

    Abdal Dayem, Ahmed; Hossain, Mohammed Kawser; Lee, Soo Bin; Kim, Kyeongseok; Saha, Subbroto Kumar; Yang, Gwang-Mo; Choi, Hye Yeon; Cho, Ssang-Goo

    2017-01-10

    Nanoparticles (NPs) possess unique physical and chemical properties that make them appropriate for various applications. The structural alteration of metallic NPs leads to different biological functions, specifically resulting in different potentials for the generation of reactive oxygen species (ROS). The amount of ROS produced by metallic NPs correlates with particle size, shape, surface area, and chemistry. ROS possess multiple functions in cellular biology, with ROS generation a key factor in metallic NP-induced toxicity, as well as modulation of cellular signaling involved in cell death, proliferation, and differentiation. In this review, we briefly explained NP classes and their biomedical applications and describe the sources and roles of ROS in NP-related biological functions in vitro and in vivo. Furthermore, we also described the roles of metal NP-induced ROS generation in stem cell biology. Although the roles of ROS in metallic NP-related biological functions requires further investigation, modulation and characterization of metallic NP-induced ROS production are promising in the application of metallic NPs in the areas of regenerative medicine and medical devices.

  18. The Role of Reactive Oxygen Species (ROS) in the Biological Activities of Metallic Nanoparticles

    PubMed Central

    Abdal Dayem, Ahmed; Hossain, Mohammed Kawser; Lee, Soo Bin; Kim, Kyeongseok; Saha, Subbroto Kumar; Yang, Gwang-Mo; Choi, Hye Yeon; Cho, Ssang-Goo

    2017-01-01

    Nanoparticles (NPs) possess unique physical and chemical properties that make them appropriate for various applications. The structural alteration of metallic NPs leads to different biological functions, specifically resulting in different potentials for the generation of reactive oxygen species (ROS). The amount of ROS produced by metallic NPs correlates with particle size, shape, surface area, and chemistry. ROS possess multiple functions in cellular biology, with ROS generation a key factor in metallic NP-induced toxicity, as well as modulation of cellular signaling involved in cell death, proliferation, and differentiation. In this review, we briefly explained NP classes and their biomedical applications and describe the sources and roles of ROS in NP-related biological functions in vitro and in vivo. Furthermore, we also described the roles of metal NP-induced ROS generation in stem cell biology. Although the roles of ROS in metallic NP-related biological functions requires further investigation, modulation and characterization of metallic NP-induced ROS production are promising in the application of metallic NPs in the areas of regenerative medicine and medical devices. PMID:28075405

  19. Finite Element Model of Oxygen Transport for the Design of Geometrically Complex Microfluidic Devices Used in Biological Studies

    PubMed Central

    Fraser, Graham M.; Goldman, Daniel; Ellis, Christopher G.

    2016-01-01

    Red blood cells play a crucial role in the local regulation of oxygen supply in the microcirculation through the oxygen dependent release of ATP. Since red blood cells serve as an oxygen sensor for the circulatory system, the dynamics of ATP release determine the effectiveness of red blood cells to relate the oxygen levels to the vessels. Previous work has focused on the feasibility of developing a microfluidic system to measure the dynamics of ATP release. The objective was to determine if a steep oxygen gradient could be developed in the channel to cause a rapid decrease in hemoglobin oxygen saturation in order to measure the corresponding levels of ATP released from the red blood cells. In the present study, oxygen transport simulations were used to optimize the geometric design parameters for a similar system which is easier to fabricate. The system is composed of a microfluidic device stacked on top of a large, gas impermeable flow channel with a hole to allow gas exchange. The microfluidic device is fabricated using soft lithography in polydimethyl-siloxane, an oxygen permeable material. Our objective is twofold: (1) optimize the parameters of our system and (2) develop a method to assess the oxygen distribution in complex 3D microfluidic device geometries. 3D simulations of oxygen transport were performed to simulate oxygen distribution throughout the device. The simulations demonstrate that microfluidic device geometry plays a critical role in molecule exchange, for instance, changing the orientation of the short wide microfluidic channel results in a 97.17% increase in oxygen exchange. Since microfluidic devices have become a more prominent tool in biological studies, understanding the transport of oxygen and other biological molecules in microfluidic devices is critical for maintaining a physiologically relevant environment. We have also demonstrated a method to assess oxygen levels in geometrically complex microfluidic devices. PMID:27829071

  20. Decoupling the influence of biological and physical processes on the dissolved oxygen in the Chesapeake Bay

    NASA Astrophysics Data System (ADS)

    Du, Jiabi; Shen, Jian

    2015-01-01

    is instructive and essential to decouple the effects of biological and physical processes on the dissolved oxygen condition, in order to understand their contribution to the interannual variability of hypoxia in Chesapeake Bay since the 1980s. A conceptual bottom DO budget model is applied, using the vertical exchange time scale (VET) to quantify the physical condition and net oxygen consumption rate to quantify biological activities. By combining observed DO data and modeled VET values along the main stem of the Chesapeake Bay, the monthly net bottom DO consumption rate was estimated for 1985-2012. The DO budget model results show that the interannual variations of physical conditions accounts for 88.8% of the interannual variations of observed DO. The high similarity between the VET spatial pattern and the observed DO suggests that physical processes play a key role in regulating the DO condition. Model results also show that long-term VET has a slight increase in summer, but no statistically significant trend is found. Correlations among southerly wind strength, North Atlantic Oscillation index, and VET demonstrate that the physical condition in the Chesapeake Bay is highly controlled by the large-scale climate variation. The relationship is most significant during the summer, when the southerly wind dominates throughout the Chesapeake Bay. The seasonal pattern of the averaged net bottom DO consumption rate (B'20) along the main stem coincides with that of the chlorophyll-a concentration. A significant correlation between nutrient loading and B'20 suggests that the biological processes in April-May are most sensitive to the nutrient loading.

  1. 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

  2. Biological Apatite Formed from Polyphosphate and Alkaline Phosphatase May Exchange Oxygen Isotopes from Water through Carbonate

    NASA Astrophysics Data System (ADS)

    Omelon, S. J.; Stanley, S. Y.; Gorelikov, I.; Matsuura, N.

    2011-12-01

    The oxygen isotopic composition in bone mineral phosphate is known to reflect the local water composition, environmental humidity, and diet1. Once ingested, biochemical processes presumably equilibrate PO43- with "body water" by the many biochemical reactions involving PO43- 2. Blake et al. demonstrated that enzymatic release of PO43- from organophosphorus compounds, and microbial metabolism of dissolved orthophosphate, significantly exchange the oxygen in precipitated apatite within environmental water3,4, which otherwise does not exchange with water at low temperatures. One of the enzymes that can cleave phosphates from organic substrates is alkaline phosphastase5, the enzyme also associated with bone mineralization. The literature often states that the mineral in bone in hydroxylapatite, however the mineral in bone is carbonated apatite that also contains some fluoride6. Deprotonation of HPO32- occurs at pH 12, which is impossibly high for biological system, and the predominate carbonate species in solution at neutral pH is HCO3-. To produce an apatite mineral without a significant hydroxyl content, it is possible that apatite biomineralization occurs through a polyphosphate pathway, where the oxygen atom required to transform polyphosphate into individual phosphate ions is from carbonate: [PO3-]n + CO32- -> [PO3-]n-1 + PO43- + CO2. Alkaline phosphatase can depolymerise polyphosphate into orthophosphate5. If alkaline phosphatase cleaves an oxygen atom from a calcium-carbonate complex, then there is no requirement for removing a hydrogen atom from the HCO3- or HPO43- ions of body water to form bioapatite. A mix of 1 mL of 1 M calcium polyphosphate hydogel, or nano-particles of calcium polyphosphate, and amorphous calcium carbonate were reacted with alkaline phosphatase, and maintained at neutral to basic pH. After two weeks, carbonated apatite and other calcium phosphate minerals were identified by powder x-ray diffraction. Orthophosphate and unreacted

  3. Biological and physiological role of reactive oxygen species--the good, the bad and the ugly.

    PubMed

    Zuo, L; Zhou, T; Pannell, B K; Ziegler, A C; Best, T M

    2015-07-01

    Reactive oxygen species (ROS) are chemically reactive molecules that are naturally produced within biological systems. Research has focused extensively on revealing the multi-faceted and complex roles that ROS play in living tissues. In regard to the good side of ROS, this article explores the effects of ROS on signalling, immune response and other physiological responses. To review the potentially bad side of ROS, we explain the consequences of high concentrations of molecules that lead to the disruption of redox homeostasis, which induces oxidative stress damaging intracellular components. The ugly effects of ROS can be observed in devastating cardiac, pulmonary, neurodegenerative and other disorders. Furthermore, this article covers the regulatory enzymes that mitigate the effects of ROS. Glutathione peroxidase, superoxide dismutase and catalase are discussed in particular detail. The current understanding of ROS is incomplete, and it is imperative that future research be performed to understand the implications of ROS in various therapeutic interventions.

  4. Oxidative metabolism of dehydroepiandrosterone (DHEA) and biologically active oxygenated metabolites of DHEA and epiandrosterone (EpiA)--recent reports.

    PubMed

    El Kihel, Laïla

    2012-01-01

    Dehydroepiandrosterone (DHEA) is a multifunctional steroid with a broad range of biological effects in humans and animals. DHEA can be converted to multiple oxygenated metabolites in the brain and peripheral tissues. The mechanisms by which DHEA exerts its effects are not well understood. However, evidence that the effects of DHEA are mediated by its oxygenated metabolites has accumulated. This paper will review the panel of oxygenated DHEA metabolites (7, 16 and 17-hydroxylated derivatives) including a number of 5α-androstane derivatives, such as epiandrosterone (EpiA) metabolites. The most important aspects of the oxidative metabolism of DHEA in the liver, intestine and brain are described. Then, this article reviews the reported biological effects of oxygenated DHEA metabolites from recent findings with a specific focus on cancer, inflammatory and immune processes, osteoporosis, thermogenesis, adipogenesis, the cardiovascular system, the brain and the estrogen and androgen receptors.

  5. Occurrence, pathways and implications of biological production of reactive oxygen species in natural waters

    NASA Astrophysics Data System (ADS)

    Zhang, T.; Hansel, C. M.; Voelker, B. M.; Lamborg, C. H.

    2014-12-01

    Reactive oxygen species (ROS), such as superoxide (O2-) and hydrogen peroxide (H2O2) play a critical role in the redox cycling of both toxic (e.g., Hg) and nutrient (e.g., Fe) metals. Despite the discovery of extracellular ROS production in various microbial cultures, including fungi, algae and bacteria, photo-dependent processes are generally considered as the predominant source of ROS in natural waters. Here we show that biological production of ROS is ubiquitous and occurs at a significant rate in freshwater and brackish water environments. Water samples were collected from three freshwater and one brackish water ponds in Cape Cod, Massachusetts, USA, periodically from 2012 to 2014. Production of O2- and H2O2 were measured in dark incubations of natural water using a chemiluminescent and a colorimetric probe, respectively. Rates of biological ROS production were obtained by comparing unfiltered with 0.2-μm filtered samples. The role of biological activity in ROS production was confirmed by the cessation of ROS production upon addition of formaldehyde. In surface water, production rates of O2- ranged from undetectable to 96.0 ± 30.0 nmol L-1 h-1, and production rates of H2O2 varied between 9.9 ± 1.3 nmol L-1 h-1 and 145.6 ± 11.2 nmol L-1 h-1. The maximum production rates of both ROS were observed in mid-summer 2013, which coincides with peak biological activity. ROS production in the water from aphotic zone was greater than in the water from photic zone. Thus, non-light dependent biological processes are likely the major contributors to ROS production in this system. Moreover, O2- production appeared to be enhanced by NADH and inhibited by proteinase-K, suggesting the possible involvement of NADH oxidoreductases in this process. The potential role of different microbial communities in ROS production, and the implications of biological ROS production for mercury speciation will also be discussed.

  6. Developing mononuclear copper-active-oxygen complexes relevant to reactive intermediates of biological oxidation reactions.

    PubMed

    Itoh, Shinobu

    2015-07-21

    Active-oxygen species generated on a copper complex play vital roles in several biological and chemical oxidation reactions. Recent attention has been focused on the reactive intermediates generated at the mononuclear copper active sites of copper monooxygenases such as dopamine β-monooxygenase (DβM), tyramine β-monooxygenase (TβM), peptidylglycine-α-hydroxylating monooxygenase (PHM), and polysaccharide monooxygenases (PMO). In a simple model system, reaction of O2 and a reduced copper(I) complex affords a mononuclear copper(II)-superoxide complex or a copper(III)-peroxide complex, and subsequent H(•) or e(-)/H(+) transfer, which gives a copper(II)-hydroperoxide complex. A more reactive species such as a copper(II)-oxyl radical type species could be generated via O-O bond cleavage of the peroxide complex. However, little had been explored about the chemical properties and reactivity of the mononuclear copper-active-oxygen complexes due to the lack of appropriate model compounds. Thus, a great deal of effort has recently been made to develop efficient ligands that can stabilize such reactive active-oxygen complexes in synthetic modeling studies. In this Account, I describe our recent achievements of the development of a mononuclear copper(II)-(end-on)superoxide complex using a simple tridentate ligand consisting of an eight-membered cyclic diamine with a pyridylethyl donor group. The superoxide complex exhibits a similar structure (four-coordinate tetrahedral geometry) and reactivity (aliphatic hydroxylation) to those of a proposed reactive intermediate of copper monooxygenases. Systematic studies based on the crystal structures of copper(I) and copper(II) complexes of the related tridentate supporting ligands have indicated that the rigid eight-membered cyclic diamine framework is crucial for controlling the geometry and the redox potential, which are prerequisites for the generation of such a unique mononuclear copper(II)-(end-on)superoxide complex

  7. Impact of oxygen cut off and starvation conditions on biological activity and physico-chemical properties of activated sludge.

    PubMed

    Villain, Maud; Clouzot, Ludiwine; Guibaud, Gilles; Marrot, Benoit

    2013-01-01

    Physico-chemical and biological parameters were monitored both throughout different oxygen cut off and starvation (OCS) times (6 h-72 h) and after the restoration of normal operational conditions. Sludge apparent viscosity and soluble extracellular polymeric substances (EPS) characteristics were measured to determine the activated sludge (AS) properties. Oxygen transfer, biological activity with specific oxygen uptake rate (SOUR) measurements during endogenous/exogenous conditions (without any external substrate/with external substrate consumption) and chemical oxygen demand (COD) removal were measured to assess the AS performances. During the different stress times, AS deflocculated as a decrease of apparent viscosity was observed and microorganisms biodegraded the released EPS to survive. After aeration return, and under endogenous conditions, size exclusion chromatographic fingerprints of soluble EPS were modified and macromolecules probably of type humic-like substances appeared in significant quantities. These new macromolecules presumably acted as biosurfactants. Consequently, the liquid surface tension, as well as the oxygen transfer rate (OTR), decreased. Under exogenous conditions, high biological activity (SOUR = 11.8 +/- 2.1 mg(O2 x g(MLVSS)(-1) x h(-1)) compensated the decrease of oxygen transfer. Finally, AS biomass maintained a constant COD degradation rate (15.7 +/- 1.9 mg(O2) x g(MLVSS)(-1) x h(-1)) before and after the disturbances for all times tested. This work demonstrates that AS microorganisms can counteract concomitant oxygen and nutrients shortage when the duration of such a condition does not exceed 72 h. Dissociation of endogenous/exogenous conditions appears to offer an ideal laboratory model to study EPS and biomass activity effects on oxygen transfer.

  8. Efficacy and tolerability of 5-day azacytidine dose-intensified regimen in higher-risk MDS.

    PubMed

    Pierdomenico, Francesca; Esteves, Susana; Almeida, Antonio

    2013-09-01

    Higher-risk myelodysplastic syndromes (MDS) are aggressive disorders with rapid progression to AML and short survival. Azacitidine has shown unprecedented survival advantage in these patients but its treatment schedule involves daily hospital administrations for 7 days every 4 weeks. Due to patient and staffing constraints, we have treated 50 patients with a 5-day dose-intensified (500 mg/m(2) total monthly dose divided in 5 days) azacitidine schedule in our center. The regimen was well tolerated, with Grade 3/4 adverse events seen in 24 % patients and only two discontinuations due to toxicity. The response rate was similar to that reported with the 7-day schedule: 16 % complete remissions, 32 % partial remissions, and 62 % transfusion independence. The median survival was 19.2 months from diagnosis. In addition, this regimen reduced hospital visits by 28 % and drug use by 30 %. Our results demonstrate the safety and efficacy of a dose-intensified 5-day regimen.

  9. Marine biological production from in situ oxygen measurements on a profiling float in the subarctic Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Bushinsky, Seth M.; Emerson, Steven

    2015-12-01

    Evaluating the organic carbon flux from the surface ocean to the interior (the marine biological pump) is essential for predictions of ocean carbon cycle feedback to climate change. One approach for determining these fluxes is to measure the concentration of oxygen in the upper ocean over a seasonal cycle, calculate the net O2 flux using an upper ocean model, and then use a stoichiometric relationship between oxygen evolved and organic carbon produced. Applying this tracer in a variety of ocean areas over seasonal cycles requires accurate O2 measurements on autonomous vehicles. Here we demonstrate this approach using an O2 sensor on a profiling float that is periodically calibrated against atmospheric pO2. Using accurate data and a model that includes all physical and biological processes influencing oxygen, we determine an annual net community production of 0.7 ± 0.5 mol C m-2 yr-1 in the northeast Pacific Ocean (50°N, 145°W) from June 2012 to June 2013. There is a strong seasonal cycle in net biological oxygen production with wintertime fluxes caused by bubble processes critical to determining the annual flux. Approximately 50% of net autotrophic production during summer months is consumed by net respiration during the winter. The result is a biological pump in the subarctic Pacific Ocean that is less than that determined by similar methods in the subtropics to the south. This estimate is significantly lower than that predicted by satellite remote sensing and global circulation models.

  10. Interconnection of reactive oxygen species chemistry across the interfaces of atmospheric, environmental, and biological processes.

    PubMed

    Anglada, Josep M; Martins-Costa, Marilia; Francisco, Joseph S; Ruiz-López, Manuel F

    2015-03-17

    Oxidation reactions are ubiquitous and play key roles in the chemistry of the atmosphere, in water treatment processes, and in aerobic organisms. Ozone (O3), hydrogen peroxide (H2O2), hydrogen polyoxides (H2Ox, x > 2), associated hydroxyl and hydroperoxyl radicals (HOx = OH and HO2), and superoxide and ozonide anions (O2(-) and O3(-), respectively) are the primary oxidants in these systems. They are commonly classified as reactive oxygen species (ROS). Atmospheric chemistry is driven by a complex system of chain reactions of species, including nitrogen oxides, hydroxyl and hydroperoxide radicals, alkoxy and peroxy radicals, and ozone. HOx radicals contribute to keeping air clean, but in polluted areas, the ozone concentration increases and creates a negative impact on plants and animals. Indeed, ozone concentration is used to assess air quality worldwide. Clouds have a direct effect on the chemical composition of the atmosphere. On one hand, cloud droplets absorb many trace atmospheric gases, which can be scavenged by rain and fog. On the other hand, ionic species can form in this medium, which makes the chemistry of the atmosphere richer and more complex. Furthermore, recent studies have suggested that air-cloud interfaces might have a significant impact on the overall chemistry of the troposphere. Despite the large differences in molecular composition, concentration, and thermodynamic conditions among atmospheric, environmental, and biological systems, the underlying chemistry involving ROS has many similarities. In this Account, we examine ROS and discuss the chemical characteristics common to all of these systems. In water treatment, ROS are key components of an important subset of advanced oxidation processes. Ozonation, peroxone chemistry, and Fenton reactions play important roles in generating sufficient amounts of hydroxyl radicals to purify wastewater. Biochemical processes within living organisms also involve ROS. These species can come from pollutants in

  11. An Uncontrolled Examination of a 5-Day Intensive Treatment for Pediatric OCD

    ERIC Educational Resources Information Center

    Whiteside, Stephen P.; Jacobsen, Amy Brown

    2010-01-01

    This study examined the feasibility of a 5-day intensive treatment for pediatric obsessive-compulsive disorder (OCD). Fifteen children with OCD received a week-long treatment based on exposure and response prevention (ERP). The intervention also emphasized teaching children and parents how to conduct ERP independently at home. All families…

  12. Zonal Wave Number 2 Rossby Wave (3.5-day oscillation) Over The Martian Lower Atmosphere

    NASA Astrophysics Data System (ADS)

    Ghosh, P.; Thokuluwa, R. K.

    2013-12-01

    Over the Mars, height (800-50 Pascal pressure coordinate) profiles of temperature (K), measured by radio occultation technique during the MGS (Mars Global Surveyor) mission, obtained for the period of 1-10 January 2006 at the Martian latitude of ~63N in almost all the longitudes are analyzed to study the characteristics of the 3.5-day oscillation. To avoid significant data gaps in a particular longitude sector, we selected a set of 7 Mars longitude regions with ranges of 0-30E, 35-60E, 65-95E, 190-230E, 250-280E, 290-320E, and 325-360E to study the global characteristics of the 3.5-day oscillation. The 3.5-day oscillation is not selected as a-priori but observed as a most significant oscillation during this period of 1-10 January 2006. It is observed that in the longitude of 0-30E, the 3.5-day oscillation shows statistically significant power (above the 95% confidence level white noise) from the lowest height (800 Pascal, 8 hPa) itself and up to the height of 450 Pascal level with the maximum power of ~130 K^2 at the 600 & 650 Pascal levels. It started to grow from the power of ~ 50 K^2 at the lowest height of 800 Pascal level and reached the maximum power in the height of 600-650 Pascal level and then it started to get lessened monotonously up to the height of 450 Pascal level where its power is ~ 20 K^2. Beyond this height and up to the height of 50 Pascal level, the wave amplitude is below the white noise level. As the phase of the wave is almost constant at all the height levels, it seems that the observed 3.5-day oscillation is a stationary wave with respect to the height. In the 35-60 E longitude sector, the vertical structure of the 3.5-day oscillation is similar to what observed for the 0-30 E longitude region but the power is statistically insignificant at all the heights. However in the 65-95E longitude sector, the wave grows from the lowest level (70 K^2) of 800 Pascal to its maximum power of 280 K^2 in the height of 700 Pascal level and then it started

  13. Biological Activities of Reactive Oxygen and Nitrogen Species: Oxidative Stress versus Signal Transduction

    PubMed Central

    Weidinger, Adelheid; Kozlov, Andrey V.

    2015-01-01

    In the past, reactive oxygen and nitrogen species (RONS) were shown to cause oxidative damage to biomolecules, contributing to the development of a variety of diseases. However, recent evidence has suggested that intracellular RONS are an important component of intracellular signaling cascades. The aim of this review was to consolidate old and new ideas on the chemical, physiological and pathological role of RONS for a better understanding of their properties and specific activities. Critical consideration of the literature reveals that deleterious effects do not appear if only one primary species (superoxide radical, nitric oxide) is present in a biological system, even at high concentrations. The prerequisite of deleterious effects is the formation of highly reactive secondary species (hydroxyl radical, peroxynitrite), emerging exclusively upon reaction with another primary species or a transition metal. The secondary species are toxic, not well controlled, causing irreversible damage to all classes of biomolecules. In contrast, primary RONS are well controlled (superoxide dismutase, catalase), and their reactions with biomolecules are reversible, making them ideal for physiological/pathophysiological intracellular signaling. We assume that whether RONS have a signal transducing or damaging effect is primarily defined by their quality, being primary or secondary RONS, and only secondly by their quantity. PMID:25884116

  14. Cryptic photosynthesis--extrasolar planetary oxygen without a surface biological signature.

    PubMed

    Cockell, Charles S; Kaltenegger, Lisa; Raven, John A

    2009-09-01

    On Earth, photosynthetic organisms are responsible for the production of virtually all the oxygen in the atmosphere. On land, vegetation reflects in the visible and leads to a "red edge," which developed about 450 million years ago on Earth and has been proposed as a biosignature for life on extrasolar planets. However, in many regions on Earth, particularly where surface conditions are extreme--in hot and cold deserts, for example--photosynthetic organisms can be driven into and under substrates where light is still sufficient for photosynthesis. These communities exhibit no detectable surface spectral signature to indicate life. The same is true of the assemblages of photosynthetic organisms at more than a few meters' depth in water bodies. These communities are widespread and dominate local photosynthetic productivity. We review known cryptic photosynthetic communities and their productivity. We have linked geomicrobiology with observational astronomy by calculating the disk-averaged spectra of cryptic habitats and identifying detectable features on an exoplanet dominated by such a biota. The hypothetical cryptic photosynthesis worlds discussed here are Earth analogues that show detectable atmospheric biosignatures like our own planet but do not exhibit a discernable biological surface feature in the disc-averaged spectrum.

  15. Estimation of biological oxygen demand and chemical oxygen demand for combined sewer systems using synchronous fluorescence spectra.

    PubMed

    Hur, Jin; Lee, Bo-Mi; Lee, Tae-Hwan; Park, Dae-Hee

    2010-01-01

    Real-time monitoring of water quality for sewer system is required for efficient sewer network design because it provides information on the precise loading of pollutant to wastewater treatment facilities and the impact of loading on receiving water. In this study, synchronous fluorescence spectra and its first derivatives were investigated using a number of wastewater samples collected in sewer systems in urban and non-urban areas, and the optimum fluorescence feature was explored for the estimation of biochemical oxygen demand (BOD) and chemical oxygen demand (COD) concentrations of sewer samples. The temporal variations in BOD and COD showed a regular pattern for urban areas whereas they were relatively irregular for non-urban areas. Irrespective of the sewer pipes and the types of the areas, two distinct peaks were identified from the synchronous fluorescence spectra, which correspond to protein-like fluorescence (PLF) and humic-like fluorescence (HLF), respectively. HLF in sewer samples appears to be associated with fluorescent whitening agents. Five fluorescence characteristics were selected from the synchronous spectra and the first-derivatives. Among the selected fluorescence indices, a peak in the PLF region (i.e., Index I) showed the highest correlation coefficient with both BOD and COD. A multiple regression approach based on suspended solid (SS) and Index I used to compensate for the contribution of SS to BOD and COD revealed an improvement in the estimation capability, showing good correlation coefficients of 0.92 and 0.94 for BOD and COD, respectively.

  16. Alterations in erythrocyte survival parameters in rats after 19.5 days aboard Cosmos 782

    NASA Technical Reports Server (NTRS)

    Leon, H. A.; Serova, L. V.; Cummins, J.; Landaw, S. A.

    1978-01-01

    Rats were subjected to 19.5 days of weightless space flight aboard the Soviet biosatellite, Cosmos 782. Based on the output of CO-14, survival parameters of a cohort of erythrocytes labeled 15.5 days preflight were evaluated upon return from orbit. These were compared to vivarium control rats injected at the same time. Statistical evaluation indicates that all survival factors were altered by the space flight. The mean potential lifespan, which was 63.0 days in the control rats, was decreased to 59.0 days in the flight rats, and random hemolysis was increased three-fold in the flight rats. The measured size of the cohort was decreased, lending further support to the idea that hemolysis was accelerated during some portion of the flight. A number of factors that might be contributory to these changes are discussed, including forces associated with launch and reentry, atmospheric and environmental parameters, dietary factors, radiation, and weightlessness.

  17. Biochemical changes in rat liver after 18.5 days of spaceflight (41566)

    NASA Technical Reports Server (NTRS)

    Abraham, S.; Lin, C.Y.; Volkmann, C. M.; Klein, H. P.

    1983-01-01

    The effect of weightlessness on liver metabolism was investigated using tissue from rats flown in earth orbit for 18.5 days on the Soviet Cosmos 936 biosatellite and the changes in the activities of 28 carbohydrate and lipid enzymes were determined. The activities of two enzymes, palmitoyl-CoA desaturase and lactate dehydrogenase, increased, while the activities of five, glycogen phosphorylase, 6-phosphogluconate dehydrogenase, both acyltransferases which act on alpha-glycerolphosphate and diglycerides, and and aconitate hydratase decreased. The other enzyme activities were found to be unchanged. In addition, increased levels of liver glycogen and palmitoleate were detected which probably resulted from the lowered glycogen phosphorylase and increased palmitoyl-CoA desaturase activities, respectively, in those animals that experienced weightlessness. All of the changes observed in the rats after 18.5 days of spaceflight disappear by 25 days after the flight.

  18. Anthracene-based fluorescent nanoprobes for singlet oxygen detection in biological media.

    PubMed

    Bresolí-Obach, Roger; Nos, Jaume; Mora, Margarita; Sagristà, Maria Lluïsa; Ruiz-González, Rubén; Nonell, Santi

    2016-10-15

    We have developed a novel singlet oxygen nanoprobe based on 9,10-anthracenedipropionic acid covalently bound to mesoporous silica nanoparticles. The nanoparticle protects the probe from interactions with proteins, which detract from its ability to detect singlet oxygen. In vitro studies show that the nanoprobe is internalized by cells and is distributed throughout the cytoplasm, thus being capable of detecting intracellularly-generated singlet oxygen.

  19. Administration of hCG 5 days after breeding and reproductive performance in nulliparous dairy goats.

    PubMed

    Fonseca, J F; Torres, C A A

    2005-12-01

    The objective of this study was to investigate the effect of hCG administration 5 days after breeding on plasma progesterone (P4) concentration and reproductive performance of oestrous-induced nulliparous dairy goats. A total of 59 nulliparous goats (36 Alpine and 23 Saanen) received intravaginal sponges with 60 mg medroxyprogesterone acetate for 9 days plus 200 IU equine chorionic gonadotrophin (eCG) and 22.5 microg d-cloprostenol 24 h before sponge removal. After detection of oestrus (day of oestrus = day 0) and breeding, 49 females were randomly assigned, according to the breed, into two treatments (T1 and T2). In T1 (n = 25) and T2 (n = 24), animals received intramuscular injection of 1 ml of saline solution (control) or 250 IU hCG, respectively, 5 days after breeding. Plasma P4 concentration (ng/ml) was determined from blood sampled on days 0, 5, 7, 13, 17, 21, 28 and 45 after breeding. Animals were scanned by transrectal ultrasound (5 MHz probe) on days 35 and 70 after breeding for detection of pregnancy. Plasma P4 concentration did not differ (p > 0.05) between treatments in all days, but it was increased (p < 0.05) in Saanen than in Alpine goats from days 13 to 45. Pregnancy and parturition rates, litter size and gestation period were similar (p > 0.05) to treatments and breeds. Results of this study indicate that human chorionic gonadotrophin (hCG) administration 5 days after breeding did not significantly alter reproductive performance in dairy nulliparous goats and that plasma P4 differed between Saanen and Alpine goats.

  20. The relationship between overactivity and opioid use in chronic pain: a 5-day observational study.

    PubMed

    Andrews, Nicole Emma; Strong, Jenny; Meredith, Pamela Joy; Fleming, Julia Ann

    2016-02-01

    With increasing concerns about the potential harm of long-term opioid therapy, there is a need for the development and implementation of alternative treatment strategies for patients with chronic pain who have been using opioids for a prolonged period of time. Based on the findings from a recent qualitative investigation that suggested there may be a bidirectional association between opioid reliance and habitual overactivity behaviour (activity engagement that significantly exacerbates pain), this study was designed to quantitatively investigate the association between opioid use and habitual overactivity over a 5-day period in a group of chronic pain patients. Participants provided a list of their prescribed pain medication, completed a self-report measure of habitual overactivity, and then commenced 5 days of data collection. Data collection required participants to wear an activity monitor and to complete a diary that detailed their daily activities and the time at which they took medication. Individuals reporting higher levels of habitual overactivity were more likely to be prescribed opioids. In addition, higher levels of habitual overactivity were associated with more frequent pro re nata ("as needed") opioid use over the 5 days, and with a discrepancy between the prescribed and actual oral morphine-equivalent daily dose, where more medication was taken than was prescribed. There was no predominant context for pro re nata use. The results of this study support the idea that habitual overactivity behaviour may play a role in the development of reliance on opioid medication and that such an association may provide a potential treatment target for opioid therapy rationalisation.

  1. Does the adolescent patellar tendon respond to 5 days of cumulative load during a volleyball tournament?

    PubMed

    van Ark, M; Docking, S I; van den Akker-Scheek, I; Rudavsky, A; Rio, E; Zwerver, J; Cook, J L

    2016-02-01

    Patellar tendinopathy (jumper's knee) has a high prevalence in jumping athletes. Excessive load on the patellar tendon through high volumes of training and competition is an important risk factor. Structural changes in the tendon are related to a higher risk of developing patellar tendinopathy. The critical tendon load that affects tendon structure is unknown. The aim of this study was to investigate patellar tendon structure on each day of a 5-day volleyball tournament in an adolescent population (16-18 years). The right patellar tendon of 41 players in the Australian Volleyball Schools Cup was scanned with ultrasound tissue characterization (UTC) on every day of the tournament (Monday to Friday). UTC can quantify structure of a tendon into four echo types based on the stability of the echo pattern. Generalized estimating equations (GEE) were used to test for change of echo type I and II over the tournament days. Participants played between eight and nine matches during the tournament. GEE analysis showed no significant change of echo type percentages of echo type I (Wald chi-square = 4.603, d.f. = 4, P = 0.331) and echo type II (Wald chi-square = 6.070, d.f. = 4, P = 0.194) over time. This study shows that patellar tendon structure of 16-18-year-old volleyball players is not affected during 5 days of cumulative loading during a volleyball tournament.

  2. [Antibacterial activity of urine after administration of ofloxacin for 5 days].

    PubMed

    Drugeon, H; Veyries, M L; Levacher, M; Garnier, M; Aymard, G; Giroud, J P; Rouveix, B

    2000-01-01

    The antibacterial activity of ofloxacin was evaluated in urine over a period of 96 h after oral administration for 5 days of 200 mg twice a day in 12 healthy female volunteers. Bacteriostatic and bactericidal activity of urines were studied for five strains of enterobacterias recovered from urinary infections: two strains of Escherichia Coli Nal-S and Nal-R, two strains of Proteus mirabilis Nal-S and Nal-R, and one strain of Klebsiella pneumoniae Nal-S. Mean urinary concentrations of ofloxacin were very high during the first 12 h following last intake. They were still above 7 mg/l till the 48th hour and above 1.6 mg/l till the 72nd hour. Bactericidal activity of urine was present for 72 h in respect of four strains studied at that time; urine was not bactericidal as regards E. coli Nal-R. After 5 days of oral treatment with ofloxacin (200 mg b.i.d.), urine retains a bactericidal activity for at least 72 h against bacterial strains of urinary tract infections.

  3. Optimal wavelengths for optoacoustic measurements of blood oxygen saturation in biological tissues

    PubMed Central

    Perekatova, Valeriya; Subochev, Pavel; Kleshnin, Mikhail; Turchin, Ilya

    2016-01-01

    The non-invasive measurement of blood oxygen saturation in blood vessels is a promising clinical application of optoacoustic imaging. Nevertheless, precise optoacoustic measurements of blood oxygen saturation are limited because of the complexities of calculating the spatial distribution of the optical fluence. In the paper error in the determination of blood oxygen saturation, associated with the use of approximate methods of optical fluence evaluation within the blood vessel, was investigated for optoacoustic measurements at two wavelengths. The method takes into account both acoustic pressure noise and the error in determined values of the optical scattering and absorption coefficients used for the calculation of the fluence. It is shown that, in conditions of an unknown (or partially known) spatial distribution of fluence at depths of 2 to 8 mm, minimal error in the determination of blood oxygen saturation is achieved at wavelengths of 658 ± 40 nm and 1069 ± 40 nm. PMID:27867709

  4. CONTINUOUS, AUTOMATED AND SIMULTANEOUS MEASUREMENT OF OXYGEN UPTAKE AND CARBON DIOXIDE EVOLUTION IN BIOLOGICAL SYSTEMS

    EPA Science Inventory

    Commercial respirometers are capable of continuously and automatically measuring oxygen uptake in bioreactors. A method for continuously and automatically measuring carbon dioxide evolution can be retrofitted to commercial respirometers. Continuous and automatic measurements of...

  5. The diversity and abundance of bacteria and oxygenic phototrophs in saline biological desert crusts in Xinjiang, northwest China.

    PubMed

    Li, Ke; Liu, Ruyin; Zhang, Hongxun; Yun, Juanli

    2013-07-01

    Although microorganisms, particularly oxygenic phototrophs, are known as the major players in the biogeochemical cycles of elements in desert soil ecosystems and have received extensive attention, still little is known about the effects of salinity on the composition and abundances of microbial community in desert soils. In this study, the diversity and abundance of bacteria and oxygenic phototrophs in biological desert crusts from Xinjiang province, which were under different salinity conditions, were investigated by using clone library and quantitative PCR (qPCR). The 16S rRNA gene phylogenetic analysis showed that cyanobacteria, mainly Microcoleus vagnitus of the order Oscillatoriales, were predominant in the low saline crusts, while other phototrophs, such as diatom, were the main microorganism group responsible for the oxygenic photosynthesis in the high saline crusts. Furthermore, the higher salt content in crusts may stimulate the growth of other bacteria, including Deinococcus-Thermus, Bacteroidetes, and some subdivisions of Proteobacteria (β-, γ-, and δ-Proteobacteria). The cpcBA-IGS gene analysis revealed the existence of novel M. vagnitus strains in this area. The qPCR results showed that the abundance of oxygenic phototrophs was significantly higher under lower saline condition than that in the higher saline crusts, suggesting that the higher salinity in desert crusts could suppress the numbers of total bacteria and phototrophic bacteria but did highly improve the diversity of salt-tolerant bacteria.

  6. [Dynamics of the protein content of human urine during 5-day immersion].

    PubMed

    Vorontsov, A L; Nesterovskaia, A Iu; Morukov, B L; Markin, A A; Zhuravleva, O A; Zabolotskaia, I V; Vostrikova, L V

    2011-01-01

    Variations in the protein spectrum (12 groups) of native daily urine were studied during 5-day dry immersion (DI) of 14 subjects at the age of 19 to 26 years using gradient electrophoresis in polyacrylamide gel. Protein excretion with urine did not alter in the course of the experiment. However, the urine proteins spectrum trended to some shifts. Excretion of low-molecular proteins decreased and of albumin increased pointing to remodulation of tubular reabsorption initiated by the experimental conditions. Steady growth of the Tamm-Horsfall protein concentration seems to be a defense reaction. There was an incremental decrease in immunoglobulins that could be associated with a reduction of glomerular filter permeability for high-molecular proteins.

  7. Biological phosphorus and nitrogen removal in sequencing batch reactors: effects of cycle length, dissolved oxygen concentration and influent particulate matter.

    PubMed

    Ginige, Maneesha P; Kayaalp, Ahmet S; Cheng, Ka Yu; Wylie, Jason; Kaksonen, Anna H

    2013-01-01

    Removal of phosphorus (P) and nitrogen (N) from municipal wastewaters is required to mitigate eutrophication of receiving water bodies. While most treatment plants achieve good N removal using influent carbon (C), the use of influent C to facilitate enhanced biological phosphorus removal (EBPR) is poorly explored. A number of operational parameters can facilitate optimum use of influent C and this study investigated the effects of cycle length, dissolved oxygen (DO) concentration during aerobic period and influent solids on biological P and N removal in sequencing batch reactors (SRBs) using municipal wastewaters. Increasing cycle length from 3 to 6 h increased P removal efficiency, which was attributed to larger portion of N being removed via nitrite pathway and more biodegradable organic C becoming available for EBPR. Further increasing cycle length from 6 to 8 h decreased P removal efficiencies as the demand for biodegradable organic C for denitrification increased as a result of complete nitrification. Decreasing DO concentration in the aerobic period from 2 to 0.8 mg L(-1) increased P removal efficiency but decreased nitrification rates possibly due to oxygen limitation. Further, sedimented wastewater was proved to be a better influent stream than non-sedimented wastewater possibility due to the detrimental effect of particulate matter on biological nutrient removal.

  8. Playback Station #2 for Cal Net and 5-day-recorder tapes

    USGS Publications Warehouse

    Eaton, Jerry P.

    1978-01-01

    A second system (Playback Station #2) has been set up to play back Cal Net 1" tapes and 5-day-recorder 1/2" tapes. As with the first playback system (Playback Station #1) the tapes are played back on a Bell and Howell VR3700B tape deck and the records are written out on a 16-channel direct-writing Siemens "0scillomink." Separate reproduce heads, tape guides, and tape tension sensor rollers are required for playing back 111 tapes and 1/2" tapes, but changing these tape deck components is a simple task that requires only a few minutes. The discriminators, patch panels, selector switches, filters, time code translators, and signal conditioning circuits for the time code translators and for the tape-speed-compensation signal are all mounted in an equipment rack that stands beside the playback tape deck. Changing playback speeds (15/16 ips or 3 3/4 ips) or changing from Cal Net tapes to 5-day-recorder tapes requires only flipping a few switches and/or changing a few patch cables on the patch panel (in addition to changing the reproduce heads, etc., to change from 1" tape to 1/2" tape). For the Cal Net tapes, the system provides for playback of 9 data channels (680 Hz thru 3060 Hz plus 400 Hz) and 3 time signals (IRIG-E, IRIG-C, and WWVB) at both 15/16 ips (x1 speed) and 3 3/4 ips (x4 speed). Available modes of compensation (using either a 4688 Hz reference or a 3125 Hz reference) are subtractive, capstan, capstan plus subtractive, or no compensation.

  9. Evaluation of 5-day therapy with telithromycin, a novel ketolide antibacterial, for the treatment of tonsillopharyngitis.

    PubMed

    Norrby, S R; Quinn, J; Rangaraju, M; Leroy, B

    2004-07-01

    A pooled analysis of two double-blind, multicentre, Phase III studies compared oral telithromycin 800 mg once-daily for 5 days with penicillin V 500 mg three-times-daily or clarithromycin 250 mg twice-daily for 10 days in the treatment of Streptococcus pyogenes (group A beta-haemolytic streptococcus; GABHS) tonsillopharyngitis. Patients aged > or = 13 years with acute GABHS tonsillopharyngitis were randomised to receive telithromycin (n = 430), penicillin (n = 197) or clarithromycin (n = 231). Clinical isolates of S. pyogenes (n = 590) obtained from throat swab samples on study entry were tested for their in-vitro susceptibility to telithromycin, clarithromycin and azithromycin. Telithromycin demonstrated in-vitro activity against the clinical isolates of S. pyogenes (MIC50/90 0.03/0.06 mg/L) higher than clarithromycin or azithromycin (MIC50/90 0.06/0.06 mg/L and 0.12/0.25 mg/L, respectively), including erythromycin-resistant strains. At the post-therapy/test of cure (TOC) visit (days 16-23), satisfactory bacteriological outcome was demonstrated for 88.3% (234/265) and 88.6% (225/254) of telithromycin- and comparator-treated patients, respectively (per-protocol population). Overall, GABHS eradication rates were 88.7% (235/265) for telithromycin and 89.0% (226/254) for comparators. The clinical cure rates at the post-therapy/TOC visit were 93.6% (248/265) and 90.9% (220/242) for telithromycin and pooled comparators, respectively. Telithromycin was generally well-tolerated. Most adverse events considered to be possibly related to study medication were gastrointestinal and of mild intensity. Discontinuations as a result of adverse events were few in both treatment groups. In conclusion, telithromycin 800 mg once-daily for 5 days was as effective as penicillin V or clarithromycin for 10 days in the treatment of GABHS tonsillopharyngitis.

  10. 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.

  11. Biologically enhanced cathode design for improved capacity and cycle life for lithium-oxygen batteries

    PubMed Central

    Oh, Dahyun; Qi, Jifa; Lu, Yi-Chun; Zhang, Yong; Shao-Horn, Yang; Belcher, Angela M.

    2014-01-01

    Lithium-oxygen batteries have a great potential to enhance the gravimetric energy density of fully packaged batteries by 2–3 times that of lithium-ion cells. Recent studies have focused on finding stable electrolytes to address poor cycling capability and improve practical limitations of current lithium-oxygen batteries. In this study, the catalyst electrode, where discharge products are deposited and decomposed, was investigated since it plays a critical role in the operation of rechargeable lithium-oxygen batteries. Here we report the electrode design principle to improve specific capacity and cycling performance of lithium-oxygen batteries by utilizing high efficiency nanocatalysts assembled by M13 virus with earth abundant elements, such as manganese oxides. By incorporating only 3–5 wt % of palladium nanoparticles in the electrode, this hybrid nanocatalyst achieves 13,350 mAh g−1c (7,340 mAh g−1c+catalyst) of specific capacity at 0.4 A g−1c and a stable cycle life up to 50 cycles (4,000 mAh g−1c, 400 mAh g−1c+catalyst) at 1 A g−1c. PMID:24220635

  12. The Role of Oxygen Radicals in Biology and Medicine 7-11 February 1983, Ventura, California,

    DTIC Science & Technology

    1983-02-11

    Hassan (Durham) Protection Against the Mutagenicity of Oxygen Free Radicals by Superoxide Dismutase and Mannitol B. Kalyanaraman (Milwaukee) The...dioxygen in the presence of activating substrates (alkyl halides, esters , methyl viologen, and transition metal complexes) results in a concerted two...carotene and mannitol . ,. . .n . a ., .,.i . .. .i ., . ., , . . . ,, , . . . . .. . . . . Antioxidant protection: interaction of vitamin E with other

  13. Biologically enhanced cathode design for improved capacity and cycle life for lithium-oxygen batteries

    NASA Astrophysics Data System (ADS)

    Oh, Dahyun; Qi, Jifa; Lu, Yi-Chun; Zhang, Yong; Shao-Horn, Yang; Belcher, Angela M.

    2013-11-01

    Lithium-oxygen batteries have a great potential to enhance the gravimetric energy density of fully packaged batteries by two to three times that of lithium ion cells. Recent studies have focused on finding stable electrolytes to address poor cycling capability and improve practical limitations of current lithium-oxygen batteries. In this study, the catalyst electrode, where discharge products are deposited and decomposed, was investigated as it has a critical role in the operation of rechargeable lithium-oxygen batteries. Here we report the electrode design principle to improve specific capacity and cycling performance of lithium-oxygen batteries by utilizing high-efficiency nanocatalysts assembled by M13 virus with earth-abundant elements such as manganese oxides. By incorporating only 3-5 wt% of palladium nanoparticles in the electrode, this hybrid nanocatalyst achieves 13,350 mAh g-1c (7,340 mAh g-1c+catalyst) of specific capacity at 0.4 A g-1c and a stable cycle life up to 50 cycles (4,000 mAh g-1c, 400 mAh g-1c+catalyst) at 1 A g-1c.

  14. Temperature dependence of haemoglobin-oxygen affinity in heterothermic vertebrates: mechanisms and biological significance.

    PubMed

    Weber, R E; Campbell, K L

    2011-07-01

    As demonstrated by August Krogh et al. a century ago, the oxygen-binding reaction of vertebrate haemoglobin is cooperative (described by sigmoid O(2) equilibrium curves) and modulated by CO(2) and protons (lowered pH) that - in conjunction with later discovered allosteric effectors (chloride, lactate and organic phosphate anions) - enhance O(2) unloading from blood in relatively acidic and oxygen-poor tissues. Based on the exothermic nature of the oxygenation of the haem groups, haemoglobin-O(2) affinity also decreases with rising temperature. This thermal sensitivity favours oxygen unloading in warm working muscles, but may become detrimental in regionally heterothermic animals, for example in cold-tolerant birds and mammals and warm-bodied fish, where it may perturb the balance between O(2) unloading and O(2) requirement in organs with substantially different temperatures than at the respiratory organs and thus commonly is reduced or obliterated. Given that the oxygenation of haemoglobin is linked with the endothermic release of allosteric effectors, increased effector interaction is an effective strategy that is widely exploited to achieve adaptive reductions in the temperature dependence of blood-O(2) affinity. The molecular mechanisms implicated in heterothermic vertebrates from different taxonomic groups reveal remarkable variability, both as regards the effectors implicated (protons in tunas, organic phosphates in sharks and billfish, chloride ions in ruminants and chloride and phosphate anions in the extinct woolly mammoth, etc.) and binding sites for the same effectors, indicating multiple evolutionary origins, but convergent physiological functionality (reductions in temperature dependence of O(2) -binding affinity that safeguard tissue O(2) supply).

  15. Determination of total iodine in nutritional and biological samples by ICP-MS following their combustion within an oxygen stream.

    PubMed

    Gélinas, Y; Krushevska, A; Barnes, R M

    1998-03-01

    A mineralization and determination method for total iodine in nutritional and biological samples is described. Combustion of the sample in an oxygen stream is followed by collection of the combustion products in a 5% water-soluble tertiary amine solution. Iodine is determined by inductively coupled plasma mass spectrometry. The accuracy and precision of the quantitative iodine analysis using standard addition is better than +/- 10%. A semi-quantitative analysis of four standard reference materials is evaluated. Owing to the presence of low-level iodine contaminant in the blank solution, the determination limit of the method is +/- 10 micrograms kg-1. Good agreement with certified iodine values is obtained for six reference materials. The use of the tertiary amine matrix solution permits the simultaneous determination of iodine and other trace metals of biological and toxicological importance, including Mn, Co, Ni, Cu, Zn, Rb, Cd, and Pb.

  16. The 6.5-day wave and its seasonal variability in the middle and upper atmosphere

    NASA Astrophysics Data System (ADS)

    Liu, H.-L.; Talaat, E. R.; Roble, R. G.; Lieberman, R. S.; Riggin, D. M.; Yee, J.-H.

    2004-11-01

    The zonal wave number 1 planetary wave of period near 6.5 days is a robust feature in the mesosphere and lower thermosphere (MLT) region with prominent seasonal variability as revealed by ground based and satellite observations. This wave and its seasonal variability are well reproduced in a recent one model year run of the National Center for Atmospheric Research thermosphere-ionosphere-mesosphere-electrodynamics general circulation model (TIME-GCM) with its lower boundary specified according to the National Centers for Environmental Prediction analysis (year 1993). Wavelet analysis of the model output shows that in the MLT region the wave maximizes before and after the equinoxes and minimizes at solstices. The wave amplitudes at the equinoxes are smaller than the peaks before and after but are still larger than the wave amplitudes at solstices. However, at the lower boundary near 30 km the wave peaks are predominantly between fall and the following spring. By examining the episodes of maximum and minimum wave amplitude and by conducting additional control experiments using the TIME-GCM, the structure of this planetary wave and the factors determining the wave characteristics and seasonal variability are studied in detail. It is found that the wave source, mean wind structure, instability, and the critical layers of the wave can all affect the wave response in the MLT region and can have a strong seasonal dependence. Before and after equinox, the wave follows the waveguide and propagates from the stratosphere to the summer mesosphere/mesopause, where it may amplify due to baroclinic/barotropic instability. Such instability is usually absent from the equinoctial atmosphere, so that there is no wave amplification at equinox. At solstice the wave decays significantly when propagating away from its winter source due to the strong eastward winter stratospheric jet. In the summer side the westward jet is also strong, and the meridional and vertical extension of the

  17. [Impact of biologically important anions on reactive oxygen species formation in water under the effect of non-ionizing physical agents].

    PubMed

    Gudkov, S V; Ivanov, V E; Karp, O É; Chernikov, A V; Belosludtsev, K N; Bobylev, A G; Astashev, M E; Gapeev, A B; Bruskov, V I

    2014-01-01

    The influence of biologically relevant anions (succinate, acetate, citrate, chloride, bicarbonate, hydroorthophosphate, dihydroorthophosphate, nitrite, nitrate) on the formation of hydrogen peroxide and hydroxyl radicals in water was studied under the effect of non-ionizing radiation: heat, laser light with a wavelength of 632.8 nm, corresponding to the maximum absorption of molecular oxygen, and electromagnetic radiation of extremely high frequencies. It has been established that various anions may both inhibit the formation of reactive oxygen species and increase it. Bicarbonate and sulfate anions included in the biological fluids' and medicinal mineral waters have significant, but opposite effects on reactive oxygen species production. Different molecular mechanisms of reactive oxygen species formation are considered under the action of the investigated physical factors involving these anions, which may influence the biological processes by signal-regulatory manner and provide a healing effect in physical therapy.

  18. Preosteoblast production 55 hours after a 12.5-day spaceflight on Cosmos 1887.

    PubMed

    Garetto, L P; Gonsalves, M R; Morey, E R; Durnova, G; Roberts, W E

    1990-01-01

    The influence of 12.5 days of spaceflight and a 55 h stressful recovery period (at 1 g) on fibroblastlike osteoblast precursor cells was assessed in the periodontal ligament (PDL) of rats that were 91 days old at launch. Nuclear morphometry was used as a marker for precursor cell differentiation in 3 microns sections cut in the midsagittal plane from the maxillary first molar. According to nuclear volume, cells were classified as preosteoblasts (C + D cells, greater than or equal to 120 microns 3) and less differentiated progenitor cells (A + A' cells, 40-79 microns 3). Compared with synchronous controls (simulated flight conditions), the 55 h postflight recovery period at 1 g resulted in a 40% decrease in the A + A' cell population, a 42% increase in the C + D cells, and a 39% increase in the number of PDL fibroblastlike cells near the bone surface. These results are consistent with a postflight osteogenic response in PDL. This recovery response occurred despite physiological stress in the flight animals that resulted in a highly significant (P less than or equal to 0.001) increase in adrenal weight. The data suggest that after spaceflight there is a strong and rapid recovery mechanism for osteoblast differentiation that is not suppressed by physiological stress.

  19. 5-day storage of platelet concentrates in CLX containers: effect of type of agitation.

    PubMed

    Snyder, E L; Bookbinder, M; Kakaiya, R; Ferri, P; Kiraly, T

    1983-01-01

    To determine the degree of platelet damage produced by different modes of agitation during storage of concentrates for 5 days in CLX blood bags, we studied pH, platelet counts, release of LDH and beta thromboglobulin, morphology and osmotic recovery. Platelets were maintained at 20-24 degrees C on elliptical, 6-rpm circular, 2-rpm circular and flat bed agitators. At 72-120 h platelet concentrates stored on the flat bed shaker had significantly lower pH values than units stored on the elliptical or on either of the circular rotators (p less than 0.05). The percent LDH discharged was highest for the units stored on the elliptical rotator (p less than 0.05). Remaining tests of platelet function were not significantly different for concentrates stored on any of the four agitators. Flat bed shakers were unable to resuspend the platelet 'button' which formed after the final preparative centrifugation. Based on our in vitro studies, we conclude that due to problems with low pH values, flat bed shakers may not be optimal for storing platelet concentrates in CLX blood bags and that some other form of agitation should be used.

  20. Preosteoblast production 55 hours after a 12.5-day spaceflight on Cosmos 1887

    NASA Technical Reports Server (NTRS)

    Garetto, L. P.; Gonsalves, M. R.; Morey, E. R.; Durnova, G.; Roberts, W. E.; Morey-Holton, E. (Principal Investigator)

    1990-01-01

    The influence of 12.5 days of spaceflight and a 55 h stressful recovery period (at 1 g) on fibroblastlike osteoblast precursor cells was assessed in the periodontal ligament (PDL) of rats that were 91 days old at launch. Nuclear morphometry was used as a marker for precursor cell differentiation in 3 microns sections cut in the midsagittal plane from the maxillary first molar. According to nuclear volume, cells were classified as preosteoblasts (C + D cells, greater than or equal to 120 microns 3) and less differentiated progenitor cells (A + A' cells, 40-79 microns 3). Compared with synchronous controls (simulated flight conditions), the 55 h postflight recovery period at 1 g resulted in a 40% decrease in the A + A' cell population, a 42% increase in the C + D cells, and a 39% increase in the number of PDL fibroblastlike cells near the bone surface. These results are consistent with a postflight osteogenic response in PDL. This recovery response occurred despite physiological stress in the flight animals that resulted in a highly significant (P less than or equal to 0.001) increase in adrenal weight. The data suggest that after spaceflight there is a strong and rapid recovery mechanism for osteoblast differentiation that is not suppressed by physiological stress.

  1. Interhemispheric structure and variability of the 5-day planetary wave from meteor radar wind measurements

    NASA Astrophysics Data System (ADS)

    Iimura, H.; Fritts, D. C.; Janches, D.; Singer, W.; Mitchell, N. J.

    2015-11-01

    A study of the quasi-5-day wave (5DW) was performed using meteor radars at conjugate latitudes in the Northern and Southern hemispheres. These radars are located at Esrange, Sweden (68° N) and Juliusruh, Germany (55° N) in the Northern Hemisphere, and at Tierra del Fuego, Argentina (54° S) and Rothera Station, Antarctica (68° S) in the Southern Hemisphere. The analysis was performed using data collected during simultaneous measurements by the four radars from June 2010 to December 2012 at altitudes from 84 to 96 km. The 5DW was found to exhibit significant short-term, seasonal, and interannual variability at all sites. Typical events had planetary wave periods that ranged between 4 and 7 days, durations of only a few cycles, and infrequent strongly peaked variances and covariances. Winds exhibited rotary structures that varied strongly among sites and between events, and maximum amplitudes up to ~ 20 m s-1. Mean horizontal velocity covariances tended to be largely negative at all sites throughout the interval studied.

  2. High removal of chemical and biochemical oxygen demand from tequila vinasses by using physicochemical and biological methods.

    PubMed

    Retes-Pruneda, Jose Luis; Davila-Vazquez, Gustavo; Medina-Ramírez, Iliana; Chavez-Vela, Norma Angelica; Lozano-Alvarez, Juan Antonio; Alatriste-Mondragon, Felipe; Jauregui-Rincon, Juan

    2014-08-01

    The goal of this research is to find a more effective treatment for tequila vinasses (TVs) with potential industrial application in order to comply with the Mexican environmental regulations. TVs are characterized by their high content of solids, high values of biochemical oxygen demand (BODs), chemical oxygen demand (COD), low pH and intense colour; thus, disposal of untreated TVs severely impacts the environment. Physicochemical and biological treatments, and a combination of both, were probed on the remediation of TVs. The use of alginate for the physicochemical treatment of TVs reduced BOD5 and COD values by 70.6% and 14.2%, respectively. Twenty white-rot fungi (WRF) strains were tested in TV-based solid media. Pleurotus ostreatus 7992 and Trametes trogii 8154 were selected due to their ability to grow on TV-based solid media. Ligninolytic enzymes' production was observed in liquid cultures of both fungi. Using the selected WRF for TVs' bioremediation, both COD and BOD5 were reduced by 88.7% and 89.7%, respectively. Applying sequential physicochemical and biological treatments, BOD5 and COD were reduced by 91.6% and 93.1%, respectively. Results showed that alginate and selected WRF have potential for the industrial treatment of TVs.

  3. Effect of biological maturation on maximal oxygen uptake and ventilatory thresholds in soccer players: an allometric approach.

    PubMed

    Cunha, Giovani; Lorenzi, Thiago; Sapata, Katiuce; Lopes, Andre Luiz; Gaya, Adroaldo Cezar; Oliveira, Álvaro

    2011-07-01

    In this study, we investigated the effect of biological maturation on maximal oxygen uptake ([Vdot]O(2max)) and ventilatory thresholds (VT(1) and VT(2)) in 110 young soccer players separated into pubescent and post-pubescent groups.. Maximal oxygen uptake and [Vdot]O(2) corresponding to VT(1) and VT(2) were expressed as absolute values, ratio standards, theoretical exponents, and experimentally observed exponents. Absolute [Vdot]O(2) (ml · min(-1)) was different between groups for VT(1), VT(2), and [Vdot]O(2max). Ratio standards (ml · kg(-1) · min(-1)) were not significantly different between groups for VT(1), VT(2), and [Vdot]O(2max). Theoretical exponents (ml · kg(-0.67) · min(-1) and ml · kg(-0.75) · min(-1)) were not properly adjusted for the body mass effects on VT(1), VT(2), and [Vdot]O(2max). When the data were correctly adjusted using experimentally observed exponents, VT(1) (ml · kg(-0.94) · min(-1)) and VT(2) (ml · kg(-0.95) · min(-1)) were not different between groups. The experimentally observed exponent for [Vdot]O(2max) (ml · kg(-0.90) · min(-1)) was different between groups (P = 0.048); however, this difference could not be attributed to biological maturation. In conclusion, biological maturation had no effect on VT(1), VT(2) or [Vdot]O(2max) when the effect of body mass was adjusted by experimentally observed exponents. Thus, when evaluating the physiological performance of young soccer players, allometric scaling needs to be taken into account instead of using theoretical approaches.

  4. Platelet function testing during 5-day storage of single and random donor plateletpheresis.

    PubMed

    Akay, O Meltem; Gündüz, Eren; Başyiğit, Hatice; Gulbas, Zafer

    2007-06-01

    Platelet concentrates are routinely manufactured from whole blood by differential centrifugation (random donor platelets-RDP) or by plateletpheresis (single donor platelets-SDP). These platelet concentrates have a storage period of 5 days and many different approaches exist to measure the condition of platelets during their storage. In this study, platelet aggregation testing using adenosine diphosphate (ADP) and collagen and flow cytometric platelet activation analysis using CD41 FITC and CD62 PE before and after ADP was performed on days 1, 3 and 5 of storage of platelet preparations. Thirty three RDPs, stored in Baxter and Kansuk blood bags and 18 SDPs stored in Fresenius blood bags were evaluated. In RDPs and in SDPs; ADP and collagen induced PA responses were decreased significantly on the 3rd and 5th days compared to 1st day. CD62 positive platelet percentage after ADP were decreased significantly on the 3rd and 5th days compared to the 1st day in Kansuk bags. Flow cytometric analysis revealed minor changes in CD41 expression after ADP on the 3rd day compared to 1st day and on the 5th day compared to 3rd day. Differences in CD62 positive platelet percentage were not significant between the RDPs and SDPs. Our results suggest that: (1) ADP and collagen induced PA responses decrease both in RDPs and SDPs during storage. (2) Flow cytometric analysis does not show major significant changes in platelet activation after ADP during storage. (3) Continous shaking on the agitator does not cause a significant change in CD62 positive platelet percentage during storage. (4) Platelet aggregation responses in RDPs stored in Baxter and Kansuk blood bags do not differ during storage.

  5. Shoot growth in aseptically cultivated daylily and haplopappus plantlets after a 5-day spaceflight

    NASA Technical Reports Server (NTRS)

    Levine, H. G.; Krikorian, A. D.

    1992-01-01

    Plantlets of daylily (Hemerocallis cv. Autumn Blaze) regenerated from cell suspensions, and 4 clonal populations of Haplopappus gracilis were aseptically cultivated aboard the Shuttle "Discovery" during a 5-day mission within NASA's Plant Growth Unit (PGU) apparatus. Daylily was selected as a representative herbaceous perennial monocotyledon and the haplopappus clones represented an annual dicotyledon. The latter included 4 strains with different physiological and morphological characteristics: two aseptic seedling clones (each generated from a single seedling) and two tissue culture-derived lines. Mean daily growth rates for the primary shoots of all plantlets averaged 4.13 mm day-1 (SD = 2.20) for the flight experiment and 4.68 mm day-1 (SD = 2.59) for the ground control. Comparable growth rates calculated by summing both the primary and secondary shoots for all plantlets were 5.94 mm day-1 (SD = 2.89) for the flight experiment and 6.38 mm day-1 (SD = 3.71) for the control. Statistically significant differences existed between: (1) flight vs control primary shoot growth (the controls growing more than plantlets subjected to spaceflight conditions), (2) the different populations (the daylily gaining more shoot material than any of the haplopappus populations and the haplopappus seedling clones outperforming the tissue culture-derived haplopappus lines), and (3) the individual Plant Growth Chambers contained within the PGU. The data suggest that some spaceflight-associated factor(s) increased the tendency for primary shoot apices to degrade or senesce, resulting in the release of apical dominance and permitting the emergence of axillary branches, which subsequently partially compensated for the reduced primary axis growth. In addition to spaceflight-associated factors, the physiologically diverse nature of the experimental material as well as environmental heterogeneities within the culture apparatus contributed to the variation in growth results. The findings

  6. Pilot study: rapidly cycling hypobaric pressure improves pain after 5 days in adiposis dolorosa

    PubMed Central

    Herbst, Karen L; Rutledge, Thomas

    2010-01-01

    Adiposis dolorosa (AD) is a rare disorder of painful nodular subcutaneous fat accompanied by fatigue, difficulty with weight loss, inflammation, increased fluid in adipose tissue (lipedema and lymphedema), and hyperalgesia. Sequential compression relieves lymphedema pain; we therefore hypothesized that whole body cyclic pneumatic hypobaric compression may relieve pain in AD. To avoid exacerbating hyperalgesia, we utilized a touch-free method, which is delivered via a high-performance altitude simulator, the Cyclic Variations in Altitude Conditioning™ (CVAC™) process. As a pilot study, 10 participants with AD completed pain and quality of life questionnaires before and after 20–40 minutes of CVAC process daily for 5 days. Participants lost weight (195.5 ± 17.6–193.8 ± 17.3 lb; P = 0.03), and bioimpedance significantly decreased (510 ± 36–490 ± 38 ohm; P = 0.01). There was a significant decrease in scores on the Pain Catastrophizing Scale (P = 0.039), in average (P = 0.002), highest (P = 0.029), lowest (P = 0.04), and current pain severity (P = 0.02) on the Visual Analogue Scale, but there was no change in pain quality by the McGill Pain Questionnaire. There were no significant changes in total and physical SF-36 scores, but the mental score improved significantly (P = 0.049). There were no changes in the Pain Disability Index or Pittsburgh Sleep Quality Index. These data present a potential, new, noninvasive means of treating pain in AD by whole body pneumatic compression as part of the CVAC process. Although randomized, controlled trials are needed to confirm these data, the CVAC process could potentially help in treating AD pain and other chronic pain disorders. PMID:21197318

  7. Outcomes of a 5-day physiotherapy programme for functional (psychogenic) motor disorders.

    PubMed

    Nielsen, G; Ricciardi, L; Demartini, B; Hunter, R; Joyce, E; Edwards, M J

    2015-03-01

    Patients with functional motor disorder (FMD) are commonly seen by physiotherapists and there is growing evidence to support a physical rehabilitation approach. There are, however, few descriptions in the literature of the content of successful physiotherapy treatment. This prospective cohort study reports the practicalities and outcomes of a pilot 5-day physiotherapy programme. Patients were referred from a specialist movement disorders clinic. The treatment consisted of education and movement retraining, with a long-term self-management focus. Education and movement retraining was based on a pathophysiological model for FMD that stresses the importance of self-focussed attention and illness belief. Patients were assessed at baseline, end of treatment and 3-month follow-up. 47 patients completed the programme, mean symptom duration was 5.5 years, 64 % were unemployed due to ill health. At the end of treatment, 65 % rated their symptoms as "very much improved" or "much improved", this reduced to 55 % at 3 months. At follow-up, there was a significant improvement in physical domains of the SF-36, Berg Balance Scale and 10 Metre Timed Walk. Measures of mental health did not change. This prospective cohort study adds to the growing evidence that supports the use of specialist physiotherapy treatment for FMD. Improvements here were made despite the cohort having characteristics associated with poor prognosis. We argue that specific treatment techniques are important and have the potential to improve physical function, quality of life and may prove to be a cost-effective treatment for selected patients with FMD.

  8. Response of mice to continuous 5-day passive hyperthermia resembles human heat acclimation.

    PubMed

    Sareh, Houtan; Tulapurkar, Mohan E; Shah, Nirav G; Singh, Ishwar S; Hasday, Jeffrey D

    2011-05-01

    Chronic repeated exposure to hyperthermia in humans results in heat acclimation (HA), an adaptive process that is attained in humans by repeated exposure to hyperthermia and is characterized by improved heat elimination and increased exercise capacity, and acquired thermal tolerance (ATT), a cellular response characterized by increased baseline heat shock protein (HSP) expression and blunting of the acute increase in HSP expression stimulated by re-exposure to thermal stress. Epidemiologic studies in military personnel operating in hot environments and elite athletes suggest that repeated exposure to hyperthermia may also exert long-term health effects. Animal models demonstrate that coincident exposure to mild hyperthermia or prior exposure to severe hyperthermia can profoundly affect the course of experimental infection and injury, but these models do not represent HA. In this study, we demonstrate that CD-1 mice continuously exposed to mild hyperthermia (ambient temperature ~37°C causing ~2°C increase in core temperature) for 5 days and then exposed to a thermal stress (42°C ambient temperature for 40 min) exhibited some of the salient features of human HA, including (1) slower warming during thermal stress and more rapid cooling during recovery and (2) increased activity during thermal stress, as well as some of the features of ATT, including (1) increased baseline expression of HSP72 and HSP90 in lung, heart, spleen, liver, and brain; and (2) blunted incremental increase in HSP72 expression following acute thermal stress. This study suggests that continuous 5-day exposure of CD-1 mice to mild hyperthermia induces a state that resembles the physiologic and cellular responses of human HA. This model may be useful for analyzing the molecular mechanisms of HA and its consequences on host responsiveness to subsequent stresses.

  9. The emerging role of reactive oxygen and nitrogen species in redox biology and some implications for plasma applications to medicine and biology

    NASA Astrophysics Data System (ADS)

    Graves, David B.

    2012-07-01

    Reactive oxygen species (ROS) and the closely related reactive nitrogen species (RNS) are often generated in applications of atmospheric pressure plasmas intended for biomedical purposes. These species are also central players in what is sometimes referred to as ‘redox’ or oxidation-reduction biology. Oxidation-reduction biochemistry is fundamental to all of aerobic biology. ROS and RNS are perhaps best known as disease-associated agents, implicated in diabetes, cancer, heart and lung disease, autoimmune disease and a host of other maladies including ageing and various infectious diseases. These species are also known to play active roles in the immune systems of both animals and plants and are key signalling molecules, among many other important roles. Indeed, the latest research has shown that ROS/RNS play a much more complex and nuanced role in health and ageing than previously thought. Some of the most potentially profound therapeutic roles played by ROS and RNS in various medical interventions have emerged only in the last several years. Recent research suggests that ROS/RNS are significant and perhaps even central actors in the actions of antimicrobial and anti-parasite drugs, cancer therapies, wound healing therapies and therapies involving the cardiovascular system. Understanding the ways ROS/RNS act in established therapies may help guide future efforts in exploiting novel plasma medical therapies. The importance of ROS and RNS to plant biology has been relatively little appreciated in the plasma biomedicine community, but these species are just as important in plants. It appears that there are opportunities for useful applications of plasmas in this area as well.

  10. Electrocoagulation process to Chemical and Biological Oxygen Demand treatment from carwash grey water in Ahvaz megacity, Iran.

    PubMed

    Mohammadi, Mohammad Javad; Takdastan, Afshin; Jorfi, Sahand; Neisi, Abdolkazem; Farhadi, Majid; Yari, Ahmad Reza; Dobaradaran, Sina; Khaniabadi, Yusef Omidi

    2017-04-01

    In this work, we present the result of an electric coagulation process with iron and aluminum electrodes for removal of chemical and biological oxygen demand (COD and BOD) from grey water in different car washes of Ahvaz, Iran. Nowadays, one of the important dangerous that can contaminate water resources for drinking, agriculture and industrial is Car wash effluent [1,2]. In this study, initial COD and BOD concentration, pH of the solution, voltage power and reaction time was investigated. The concentration level of remaining COD and BOD in samples was measured, using DR/5000 UV-vis HACH spectrophotometer [3,4]. The effects of contact time, initial pH, electrical potential and voltage data on removal of COD and BOD were presented. Statistical analysis of the data was carried out using Special Package for Social Sciences (SPSS 16).

  11. Oxygen Modulates the Effectiveness of Granuloma Mediated Host Response to Mycobacterium tuberculosis: A Multiscale Computational Biology Approach.

    PubMed

    Sershen, Cheryl L; Plimpton, Steven J; May, Elebeoba E

    2016-01-01

    Mycobacterium tuberculosis associated granuloma formation can be viewed as a structural immune response that can contain and halt the spread of the pathogen. In several mammalian hosts, including non-human primates, Mtb granulomas are often hypoxic, although this has not been observed in wild type murine infection models. While a presumed consequence, the structural contribution of the granuloma to oxygen limitation and the concomitant impact on Mtb metabolic viability and persistence remains to be fully explored. We develop a multiscale computational model to test to what extent in vivo Mtb granulomas become hypoxic, and investigate the effects of hypoxia on host immune response efficacy and mycobacterial persistence. Our study integrates a physiological model of oxygen dynamics in the extracellular space of alveolar tissue, an agent-based model of cellular immune response, and a systems biology-based model of Mtb metabolic dynamics. Our theoretical studies suggest that the dynamics of granuloma organization mediates oxygen availability and illustrates the immunological contribution of this structural host response to infection outcome. Furthermore, our integrated model demonstrates the link between structural immune response and mechanistic drivers influencing Mtbs adaptation to its changing microenvironment and the qualitative infection outcome scenarios of clearance, containment, dissemination, and a newly observed theoretical outcome of transient containment. We observed hypoxic regions in the containment granuloma similar in size to granulomas found in mammalian in vivo models of Mtb infection. In the case of the containment outcome, our model uniquely demonstrates that immune response mediated hypoxic conditions help foster the shift down of bacteria through two stages of adaptation similar to the in vitro non-replicating persistence (NRP) observed in the Wayne model of Mtb dormancy. The adaptation in part contributes to the ability of Mtb to remain dormant

  12. Oxygen Modulates the Effectiveness of Granuloma Mediated Host Response to Mycobacterium tuberculosis: A Multiscale Computational Biology Approach

    DOE PAGES

    Sershen, Cheryl L.; Plimpton, Steven J.; May, Elebeoba E.

    2016-02-15

    Mycobacterium tuberculosis associated granuloma formation can be viewed as a structural immune response that can contain and halt the spread of the pathogen. In several mammalian hosts, including non-human primates, Mtb granulomas are often hypoxic, although this has not been observed in wild type murine infection models. While a presumed consequence, the structural contribution of the granuloma to oxygen limitation and the concomitant impact on Mtb metabolic viability and persistence remains to be fully explored. We develop a multiscale computational model to test to what extent in vivo Mtb granulomas become hypoxic, and investigate the effects of hypoxia on hostmore » immune response efficacy and mycobacterial persistence. Our study integrates a physiological model of oxygen dynamics in the extracellular space of alveolar tissue, an agent-based model of cellular immune response, and a systems biology-based model of Mtb metabolic dynamics. Our theoretical studies suggest that the dynamics of granuloma organization mediates oxygen availability and illustrates the immunological contribution of this structural host response to infection outcome. Furthermore, our integrated model demonstrates the link between structural immune response and mechanistic drivers influencing Mtbs adaptation to its changing microenvironment and the qualitative infection outcome scenarios of clearance, containment, dissemination, and a newly observed theoretical outcome of transient containment. We observed hypoxic regions in the containment granuloma similar in size to granulomas found in mammalian in vivo models of Mtb infection. In the case of the containment outcome, our model uniquely demonstrates that immune response mediated hypoxic conditions help foster the shift down of bacteria through two stages of adaptation similar to thein vitro non-replicating persistence (NRP) observed in the Wayne model of Mtb dormancy. Finally, the adaptation in part contributes to the ability of Mtb to

  13. Oxygen Modulates the Effectiveness of Granuloma Mediated Host Response to Mycobacterium tuberculosis: A Multiscale Computational Biology Approach

    PubMed Central

    Sershen, Cheryl L.; Plimpton, Steven J.; May, Elebeoba E.

    2016-01-01

    Mycobacterium tuberculosis associated granuloma formation can be viewed as a structural immune response that can contain and halt the spread of the pathogen. In several mammalian hosts, including non-human primates, Mtb granulomas are often hypoxic, although this has not been observed in wild type murine infection models. While a presumed consequence, the structural contribution of the granuloma to oxygen limitation and the concomitant impact on Mtb metabolic viability and persistence remains to be fully explored. We develop a multiscale computational model to test to what extent in vivo Mtb granulomas become hypoxic, and investigate the effects of hypoxia on host immune response efficacy and mycobacterial persistence. Our study integrates a physiological model of oxygen dynamics in the extracellular space of alveolar tissue, an agent-based model of cellular immune response, and a systems biology-based model of Mtb metabolic dynamics. Our theoretical studies suggest that the dynamics of granuloma organization mediates oxygen availability and illustrates the immunological contribution of this structural host response to infection outcome. Furthermore, our integrated model demonstrates the link between structural immune response and mechanistic drivers influencing Mtbs adaptation to its changing microenvironment and the qualitative infection outcome scenarios of clearance, containment, dissemination, and a newly observed theoretical outcome of transient containment. We observed hypoxic regions in the containment granuloma similar in size to granulomas found in mammalian in vivo models of Mtb infection. In the case of the containment outcome, our model uniquely demonstrates that immune response mediated hypoxic conditions help foster the shift down of bacteria through two stages of adaptation similar to thein vitro non-replicating persistence (NRP) observed in the Wayne model of Mtb dormancy. The adaptation in part contributes to the ability of Mtb to remain dormant

  14. Oxygen Modulates the Effectiveness of Granuloma Mediated Host Response to Mycobacterium tuberculosis: A Multiscale Computational Biology Approach

    SciTech Connect

    Sershen, Cheryl L.; Plimpton, Steven J.; May, Elebeoba E.

    2016-02-15

    Mycobacterium tuberculosis associated granuloma formation can be viewed as a structural immune response that can contain and halt the spread of the pathogen. In several mammalian hosts, including non-human primates, Mtb granulomas are often hypoxic, although this has not been observed in wild type murine infection models. While a presumed consequence, the structural contribution of the granuloma to oxygen limitation and the concomitant impact on Mtb metabolic viability and persistence remains to be fully explored. We develop a multiscale computational model to test to what extent in vivo Mtb granulomas become hypoxic, and investigate the effects of hypoxia on host immune response efficacy and mycobacterial persistence. Our study integrates a physiological model of oxygen dynamics in the extracellular space of alveolar tissue, an agent-based model of cellular immune response, and a systems biology-based model of Mtb metabolic dynamics. Our theoretical studies suggest that the dynamics of granuloma organization mediates oxygen availability and illustrates the immunological contribution of this structural host response to infection outcome. Furthermore, our integrated model demonstrates the link between structural immune response and mechanistic drivers influencing Mtbs adaptation to its changing microenvironment and the qualitative infection outcome scenarios of clearance, containment, dissemination, and a newly observed theoretical outcome of transient containment. We observed hypoxic regions in the containment granuloma similar in size to granulomas found in mammalian in vivo models of Mtb infection. In the case of the containment outcome, our model uniquely demonstrates that immune response mediated hypoxic conditions help foster the shift down of bacteria through two stages of adaptation similar to thein vitro non-replicating persistence (NRP) observed in the Wayne model of Mtb dormancy. Finally, the adaptation in part contributes to the ability of Mtb to remain

  15. Versatility of biological non-heme Fe(II) centers in oxygen activation reactions

    PubMed Central

    Kovaleva, Elena G; Lipscomb, John D

    2009-01-01

    Oxidase and oxygenase enzymes allow the use of relatively unreactive O2 in biochemical reactions. Many of the mechanistic strategies employed in nature for this key reaction are represented within the 2-His-1-carboxylate facial triad family of non-heme Fe(II) containing enzymes. The open face of the metal coordination sphere opposite the three endogenous ligands participates directly in the reaction chemistry. Here, data from several studies are presented showing that reductive O2 activation within this family is initiated by substrate (and in some cases co-substrate or cofactor) binding, which then allows coordination of O2 to the metal. From this starting point, both the O2 activation process and the reactions with substrates diverge broadly. The reactive species formed in these reactions have been proposed to encompass four oxidation states of iron and all forms of reduced O2 as well as several of the reactive oxygen species that derive from O–O bond cleavage. PMID:18277980

  16. Identification and biological activities of a new antiangiogenic small molecule that suppresses mitochondrial reactive oxygen species

    SciTech Connect

    Kim, Ki Hyun; Park, Ju Yeol; Jung, Hye Jin; Kwon, Ho Jeong

    2011-01-07

    Research highlights: {yields} YCG063 was screened as a new angiogenesis inhibitor which suppresses mitochondrial ROS generation in a phenotypic cell-based screening of a small molecule-focused library. {yields} The compound inhibited in vitro and in vivo angiogenesis in a dose-dependent manner. {yields} This new small molecule tool will provide a basis for a better understanding of angiogenesis driven under hypoxic conditions. -- Abstract: Mitochondrial reactive oxygen species (ROS) are associated with multiple cellular functions such as cell proliferation, differentiation, and apoptosis. In particular, high levels of mitochondrial ROS in hypoxic cells regulate many angiogenesis-related diseases, including cancer and ischemic disorders. Here we report a new angiogenesis inhibitor, YCG063, which suppressed mitochondrial ROS generation in a phenotypic cell-based screening of a small molecule-focused library with an ArrayScan HCS reader. YCG063 suppressed mitochondrial ROS generation under a hypoxic condition in a dose-dependent manner, leading to the inhibition of in vitro angiogenic tube formation and chemoinvasion as well as in vivo angiogenesis of the chorioallantoic membrane (CAM) at non-toxic doses. In addition, YCG063 decreased the expression levels of HIF-1{alpha} and its target gene, VEGF. Collectively, a new antiangiogenic small molecule that suppresses mitochondrial ROS was identified. This new small molecule tool will provide a basis for a better understanding of angiogenesis driven under hypoxic conditions.

  17. Oxygen bomb combustion of biological samples for inductively coupled plasma optical emission spectrometry

    NASA Astrophysics Data System (ADS)

    Souza, Gilberto B.; Carrilho, Elma Neide V. M.; Oliveira, Camila V.; Nogueira, Ana Rita A.; Nóbrega, Joaquim A.

    2002-12-01

    A rapid sample preparation method is proposed for decomposition of milk powder, corn bran, bovine and fish tissues, containing certified contents of the analytes. The procedure involves sample combustion in a commercial stainless steel oxygen bomb operating at 25 bar. Most of the samples were decomposed within 5 min. Diluted nitric acid or water-soluble tertiary amines 10% v/v were used as absorption solutions. Calcium, Cu, K, Mg, Na, P, S and Zn were recovered with the bomb washings and determined by inductively coupled plasma optical emission spectrometry (ICP-OES). Ethanol mixed with paraffin was used as a combustion aid to allow complete combustion. A cooling step prior releasing of the bomb valve was employed to increase the efficiency of sample combustion. Iodine was also determined in milk samples spiked with potassium iodide to evaluate the volatilization and collection of iodine in amine CFA-C medium and the feasibility of its determination by ICP-OES with axial view configuration. Most of the element recoveries in the samples were between 91 and 105% and the certified and found contents exhibited a fair agreement at a 95% confidence level.

  18. Mitochondrial Flash: Integrative Reactive Oxygen Species and pH Signals in Cell and Organelle Biology

    PubMed Central

    Gong, Guohua; Wang, Xianhua; Wei-LaPierre, Lan; Cheng, Heping; Dirksen, Robert

    2016-01-01

    Abstract Significance: Recent breakthroughs in mitochondrial research have advanced, reshaped, and revolutionized our view of the role of mitochondria in health and disease. These discoveries include the development of novel tools to probe mitochondrial biology, the molecular identification of mitochondrial functional proteins, and the emergence of new concepts and mechanisms in mitochondrial function regulation. The discovery of “mitochondrial flash” activity has provided unique insights not only into real-time visualization of individual mitochondrial redox and pH dynamics in live cells but has also advanced understanding of the excitability, autonomy, and integration of mitochondrial function in vivo. Recent Advances: The mitochondrial flash is a transient and stochastic event confined within an individual mitochondrion and is observed in a wide range of organisms from plants to Caenorhabditis elegans to mammals. As flash events involve multiple transient concurrent changes within the mitochondrion (e.g., superoxide, pH, and membrane potential), a number of different mitochondrial targeted fluorescent indicators can detect flash activity. Accumulating evidence indicates that flash events reflect integrated snapshots of an intermittent mitochondrial process arising from mitochondrial respiration chain activity associated with the transient opening of the mitochondrial permeability transition pore. Critical Issues: We review the history of flash discovery, summarize current understanding of flash biology, highlight controversies regarding the relative roles of superoxide and pH signals during a flash event, and bring forth the integration of both signals in flash genesis. Future Directions: Investigations using flash as a biomarker and establishing its role in cell signaling pathway will move the field forward. Antioxid. Redox Signal. 25, 534–549. PMID:27245241

  19. Oxygen in human health from life to death--An approach to teaching redox biology and signaling to graduate and medical students.

    PubMed

    Briehl, Margaret M

    2015-08-01

    In the absence of oxygen human life is measured in minutes. In the presence of oxygen, normal metabolism generates reactive species (ROS) that have the potential to cause cell injury contributing to human aging and disease. Between these extremes, organisms have developed means for sensing oxygen and ROS and regulating their cellular processes in response. Redox signaling contributes to the control of cell proliferation and death. Aberrant redox signaling underlies many human diseases. The attributes acquired by altered redox homeostasis in cancer cells illustrate this particularly well. This teaching review and the accompanying illustrations provide an introduction to redox biology and signaling aimed at instructors of graduate and medical students.

  20. Effect of different carbon sources on the biological phosphorus removal by a sequencing batch reactor using pressurized pure oxygen.

    PubMed

    Wei, Jie; Imai, Tsuyoshi; Higuchi, Takaya; Arfarita, Novi; Yamamoto, Koichi; Sekine, Masahiko; Kanno, Ariyo

    2014-05-04

    The effect of different carbon source on the efficiency of enhanced biological phosphorus removal (EBPR) from synthetic wastewater with acetate and two ratios of acetate/starch as a carbon source was investigated. Three pressurized pure oxygen sequencing batch reactor (POSBR) experiments were operated. The reactors (POSBR1, POSBR2 and POSBR3) were developed and studied at different carbon source ratios of 100% acetate, 75% acetate plus 25% starch and 50% acetate plus 50% starch, respectively. The results showed that POSBR1 had a higher phosphate release-to-uptake ratio and, respectively, in a much higher phosphorus removal efficiency (93.8%) than POSBR2 (84.7%) and POSBR3 (77.3%) within 30 days of operation. This indicated that the phosphorus removal efficiency decreased the higher the starch concentration was. It was also found that POSBR1 produced more polyhydroxyalkanoates (PHAs) than the other reactors. Based on the effect of the carbon source on the PHA concentration and consumption, the conditions of POSBR1 were favourable for the growth of polyphosphate-accumulating organisms and therefore, beneficial for the biological phosphorus removal process.

  1. Tripping Up Trp: Modification of Protein Tryptophan Residues by Reactive Oxygen Species, Modes of Detection, and Biological Consequences

    PubMed Central

    Ehrenshaft, Marilyn; Deterding, Leesa J.; Mason, Ronald P.

    2015-01-01

    Proteins comprise a majority of the dry weight of a cell, rendering them a major target for oxidative modification. Oxidation of proteins can result in significant alterations in protein molecular mass such as breakage of the polypeptide backbone, and/or polymerization of monomers into dimers, multimers and sometimes into insoluble aggregates. Protein oxidation can also result in structural changes to amino acid residue side chains, conversions which have only a modest effect on protein size but can have widespread consequences for protein function. There are a wide range of rate constants for amino acid reactivity, with cysteine, methionine, tyrosine, phenylalanine and tryptophan having the highest rate constants with commonly encountered biological oxidants. Free tryptophan and tryptophan protein residues react at a diffusion limited rate with hydroxyl radical, and also have high rate constants for reactions with singlet oxygen and ozone. Although oxidation of proteins in general and tryptophan residues specifically can have effects detrimental to the health of cells and organisms, some modifications are neutral while others contribute to the function of the protein in question or may act as a signal that damaged proteins need to be replaced. This review provides a brief overview of the chemical mechanisms by which tryptophan residues become oxidized, presents both the strengths and weaknesses of some of the techniques used to detect these oxidative interactions and discusses selected examples of the biological consequences of tryptophan oxidation in proteins from animals, plants and microbes. PMID:26393422

  2. Synthesis and Spectroscopic and Biological Activities of Zn(II) Porphyrin with Oxygen Donors

    PubMed Central

    Bajju, Gauri Devi; Kundan, Sujata; Bhagat, Madhulika; Gupta, Deepmala; Kapahi, Ashu; Devi, Geeta

    2014-01-01

    Results of investigation of the physicochemical properties of zinc complexes containing substituted phenols as axial ligand having general formula [X-Zn-t(p-CH3) PP] [where X = different phenolates as axial ligand] in impurity-free organic solvent are presented. The four-coordinated zinc porphyrin accepts one axial ligand in 1 : 1 molar ratio to form five-coordinated complex, which is purified by column chromatography and characterized by physicochemical, biological evaluation and TGA/DTA studies. Absorption spectra show two principal effects: a red shift for phenols bearing substituted electron releasing groups (−CH3, −NH2) and blue shift for phenols bearing electron withdrawing groups (−NO2, −Cl) relative to Zn-t(p-CH3) PP, respectively. 1H NMR spectra show that the protons of the phenol ring axially attached to the central metal ion are merged with the protons of the porphyrin ring. Fluorescence spectra show two fluorescence peaks in the red region with emission ranging from 550 nm to 700 nm. IR spectra confirm the appearance of Zn-NPor and Zn-O vibrational frequencies, respectively. According to the thermal studies, the complexes have a higher thermal stability and the decomposition temperature of these complexes depends on the axial ligation. The respective complexes of X-ZnII-t(p-CH3) PP were found to possess higher antifungal activity (up to 90%) and higher in vitro cytotoxicity against human cancer cells lines. PMID:24744692

  3. Dissolved Oxygen Dynamics in Coastal Pacific Northwest Rivers: Biological Controls and Management Options

    NASA Astrophysics Data System (ADS)

    Sobota, D. J.; Foster, E.; Michie, R.; Waltz, D.

    2014-12-01

    In Oregon's Central Coast Range (OCR), dissolved O2 concentrations in at least 10% of stream length frequently dip below state standards set to ensure survival and reproduction of native salmonids. We examined O2 dynamics on 12 OCR rivers during times of the year when standards had been violated. Continuous dissolved O2 data were collected 15 minutes apart over a 24-hour period during spring (May - June) or fall (September - November) 2008 on each river. We modeled O2 dynamics for each river with parameters describing O2 exchange with the atmosphere, production of O2 from gross primary production (GPP), and consumption of O2 by ecosystem respiration (ER) fit to observed data. Average nighttime atmospheric O2 exchange and ER were estimated by regressing interval changes in dissolved O2 concentrations between measurements with corresponding O2 saturation deficits. GPP for each daytime sampling interval was calculated as the difference between O2 saturation deficit and the sum of temperature-corrected reaeration and ecosystem respiration. All regression models developed for estimating night-time reaeration and ER were highly significant (p<0.03; adjusted r2=0.17 - 0.77). GPP ranged from 0.62 to 14.95 mg O2 L-1 d-1, ER ranged from -1.21 mg O2 L-1 d-1, and net daily metabolism (NDM; net O2 flux controlled by biological processes) ranged from -11.64 to 3.75 mg O2 L-1 d-1 across all rivers and seasons. Increased aquatic productivity resulting from adjacent and upstream human activities likely altered dissolved O2 dynamics in these rivers. Through scenario analysis, we found that at one river (Alsea), GPP and ER would need to be reduced by 85 and 73%, respectively, to meet the state standard (95% saturation). Our modeling approach can be connected with management actions across a variety of spatial and temporal scales, ranging from local, riparian-scale manipulations of shading and organic matter input to watershed and regional nutrient and temperature management.

  4. Carbon, oxygen and biological productivity in the Southern Ocean in and out the Kerguelen plume: CARIOCA drifter results

    NASA Astrophysics Data System (ADS)

    Merlivat, L.; Boutin, J.; d'Ovidio, F.

    2015-06-01

    dissolved oxygen (O2) highlight biological events lasting from 2 to 4 days. Stoichiometric ratios, O2 / C, between 1.1 and 1.4 are observed indicating new and regenerated production regimes. NCP estimates range from 60 to 140 mmol C m-2 d-1.

  5. Carbon, oxygen and biological productivity in the Southern Ocean in and out the Kerguelen plume: CARIOCA drifter results

    NASA Astrophysics Data System (ADS)

    Merlivat, L.; Boutin, J.; d'Ovidio, F.

    2014-12-01

    The Kerguelen Plateau region in the Indian sector of the Southern Ocean supports annually a large-scale phytoplankton bloom which is naturally fertilized with iron. As part of the second Kerguelen Ocean and Plateau compared Study expedition (KEOPS2) in austral spring (October-November 2011), one Carioca buoy was deployed east of the Kerguelen plateau. It drifted eastward downstream in the Kerguelen plume. Hourly surface measurements of pCO2, O2 and ancillary observations were collected between 1 November 2011 to 12 February 2012 with the aim of characterizing the spatial and temporal variability of the biological Net Community Production (NCP) downstream the Kerguelen plateau, assess the impact of iron-induced productivity on the biological carbon consumption and consequently on the CO2 flux exchanged at the air-sea interface. The trajectory of the buoy until mid-December was within the longitude range, 72-83° E, close to the polar front and then in the polar frontal zone, PFZ, until 97° E. From 17 November to 16 December, the buoy drifted within the Kerguelen plume following a filament carrying dissolved iron, DFe, for a total distance of 700 km. In the first part of the trajectory, the ocean surface waters are a sink for CO2 and a source for CO2, with fluxes of respective mean values equal to -8 and +38 mmol CO2 m-2 d-1. Eastward, as the buoy escapes the iron enriched filament, the fluxes are in opposite direction, with respective mean values of +5 and -48 mmol O2 m-2 d-1. These numbers clearly indicate the strong impact of biological processes on the biogeochemistry in the surface waters within the Kerguelen plume in November-mid-December, while it is undetectable eastward in the PFZ from mid-December to mid-February. While the buoy follows the Fe enriched filament, simultaneous observations of dissolved inorganic carbon, DIC, and dissolved oxygen, O2, highlight biological events lasting from 2 to 4 days. Stoichiometric ratios, O2/C, between 1.1 and 1.4 are

  6. Continuing Assessment of the 5-Day Sodium Carbonate-Ammonium Nitrate Extraction Assay as an Indicator Test for Silicon Fertilizers.

    PubMed

    Zellner, Wendy; Friedrich, Russell L; Kim, Sujin; Sturtz, Douglas; Frantz, Jonathan; Altland, James; Krause, Charles

    2015-01-01

    The 5-day sodium carbonate-ammonium nitrate extraction assay (5-day method) has been recognized by the American Association of Plant Food Control Officials as a validated test method to identify fertilizers or beneficial substances that provide plant-available silicon (Si). The test method used the molybdenum blue colorimetric assay to quantify percentage Si; however, laboratories may use inductively coupled plasma optical emission spectroscopy (ICP-OES) for elemental analysis. To examine the use of either colorimetric or ICP-OES methods for Si determination, the 5-day method was performed on the following Si-containing compounds; wollastonite, sand, biochar, and a basic oven furnace (BOF) slag. Grow-out studies using Zinnia elegans were also performed using varying rates of the wollastonite, biochar, and BOF slag. Our results show using the 5-day method, wollastonite had the highest extracted amounts of silicic acid (H4SiO4) at 4% followed by biochar (2%), BOF slag (1%), and sand (0%). Extraction values calculated using either the molybdenum blue colorimetric assay or ICP-OES for detection of the H4SiO4 had a significant correlation, supporting the application of either detection method for this type of analysis. However, when extracted values were compared to amounts of Si taken up by the plants, the 5-day method overestimated both wollastonite and biochar. While this method is a valid indicator test for determining a soluble Si source, other plant species and methods should be perused to potentially provide more quantitative analyses for plant-available Si content of all materials.

  7. Maternal and neonatal evaluation of derivated reactive oxygen metabolites (d-ROMs) and biological antioxidant potential in the horse.

    PubMed

    Sgorbini, M; Bonelli, F; Marmorini, P; Biagi, G; Corazza, M; Pasquini, A

    2015-01-01

    The aim of the present work was to evaluate derivated reactive oxygen metabolites (d-ROMs) and biological antioxidant potential (BAP) in mares and foals to study perinatal oxidative status. A total of 60 animals were included in the present study. Maternal and foal venous blood samples were collected immediately after delivery along with a sample drawn from one of the umbilical arteries, and plasma samples were evaluated for lactatemia, d-ROMs, and BAP. The t test for unpaired data was applied between mares versus umbilical artery blood versus foals, both for d-ROMs and BAP. The Pearson test with two-tailed P value and a confidence interval of 95% was performed between d-ROMs and BAP and between d-ROMs and lactatemia, both for mares and foals. Finally, the t test for unpaired data was performed between fillies and colts. The t test showed differences between mares versus their own foals versus umbilical artery blood but not foals versus. umbilical artery blood, both for d-ROMs and BAP. A positive correlation was found both in mares and foals between BAP and d-ROMs and in mares between lactatemia and d-ROM. No differences in gender were found in BAP concentration. Our data are in line to previous studies performed in women and cattle.

  8. Air-Water Exchange of N2 and O2 from In Situ Measurements in the Subarctic and Subtropical Pacific Oceans: Oxygen Flux and Net Biological Production

    NASA Astrophysics Data System (ADS)

    Emerson, S.

    2008-12-01

    In-situ measurements of wind speed, atmospheric pressure, surface-ocean total dissolved gas pressure and oxygen concentration are used to determine the flux of nitrogen and oxygen between the ocean and atmosphere in the subarctic and subtropical Pacific Oceans. Measurements were made hourly over a period of about one year on surface moorings at the Hawaii Ocean Time series (HOT) in 2005 and at Station P in 2007. Gas pressures in the mixed layer were determined using a gas tension device (GTD) and an oxygen sensor calibrated by Winkler O2 titrations. The pressures of nitrogen and oxygen vary smoothly within a few percent of atmospheric saturation in the subtropical Pacific Ocean, but in the subarctic surface waters these values are punctuated by very rapid excursions caused by storms. The primary flux of oxygen in the upper ocean is between the ocean and atmosphere. We use a simple ocean mixed-layer model to determine this flux and estimate the net biological oxygen production at these sites. Assuming that the net biological oxygen and carbon production are stoichiometrically related over an annual cycle, this method provides a measure of the annual carbon export from the mixed layer, an important component of the ocean's role in the global carbon cycle. There is net biological O2 production most of the year in the subtropical ocean; however, little evidence of net O2 production in the wintertime in the subarctic Pacific. This contrasts with earlier 14C primary production measurements which indicate that wintertime production is about half that in summer at both locations. Annual estimates of biologically produced carbon export at these two sites will be contrasted at the presentation in the fall meeting. This research indicates that it should be possible to derive estimates of the net annual air-water oxygen fluxes caused by biological production at any location of the open ocean where there is a surface mooring. Large, abrupt atmospheric pressure changes (up to 50

  9. Translocation and biokinetic behavior of nanoscaled europium oxide particles within 5 days following an acute inhalation in rats.

    PubMed

    Creutzenberg, Otto; Kock, Heiko; Schaudien, Dirk

    2016-03-01

    Nanoscaled europium oxide (Eu2O3) particles were inhaled by rats after acute exposure and the potential translocation of particles followed by chemical analysis and transmission electron microscopy (TEM) was investigated. An aqueous dispersion (phosphate buffer/bovine serum albumin) of a commercially available Eu2O3 particle fraction consisting partially of nanoscaled particles was aerosolized with pressurized air. After rapid evaporation, rats inhaled the dry aerosol for 6 h in a single exposure resulting in an alveolar calculated dose of approximately 39.5 μg Eu2O3. Using chemical analysis, 36.8 μg Eu2O3 was detected 1 h after lung inhalation. The amount declined slightly to 34.5 μg after 1 day and 35.0 μg after 5 days. The liver showed an increase of Eu2O3 from 32.3 ng 1 h up to 294 ng 5 days after inhalation. Additionally, lung-associated lymph nodes, thymus, kidneys, heart and testis exhibited an increase of europium over the period investigated. In the blood, the highest amount of europium was found 1 h after treatment whereas feces, urine and mesenteric lymph nodes revealed the highest amount 1 day after treatment. Using TEM analysis, particles could be detected only in lungs, and in the liver, no particles were detectable. In conclusion, the translocation of Eu2O3 within 5 days following inhalation could be determined very precisely by chemical analysis. A translocation of Eu2O3 particulate matter to liver was not detectable by TEM analysis; thus, the overproportional level of 0.8% of the lung load observed in the liver after 5 days suggests a filtering effect of dissolved europium with accumulation.

  10. Initiation of GnRH agonist treatment on 3-5 days postoperatively in endometriosis patients: a randomized controlled trial.

    PubMed

    Gong, Lili; Zhang, Shaofen; Han, Yi; Long, Qiqi; Zou, Shien; Cao, Yuankui

    2015-08-01

    Seventy patients with stage III or IV endometriosis were randomly assigned to 2 groups after conservative surgery. Group O (n = 35) received 3 cycles of a 28-day gonadotropin-releasing hormone agonist (GnRH-a) treatment (goserelin, 3.6 mg) starting 3-5 days postoperatively. Group M (n = 35) received the same treatment starting on days 1-5 of menstruation. Groups were further subdivided according to add-back treatment. Pre- and posttreated levels of estradiol (E2 ), follicle stimulating hormone (FSH), and luteinizing hormone (LH) and visual analog scale (VAS), Kupperman menopausal index (KMI), and bone mineral density (BMD) scores were recorded. The incidence of uterine bleeding was assessed. In both groups, serum levels of E2 , FSH, and LH and VAS scores decreased significantly after treatment. Spotting was the most frequent bleeding pattern. During cycle 1, the bleeding time in group M was much longer that than that in group O (P =.001), and the bleeding rate in group M was significantly higher than that in group O (P =.024, RR = 1.185). In patients with stage III or IV endometriosis, the efficacy of GnRH-a initiated 3-5 days postoperatively was equivalent to that of GnRH-a initiated on days 1-5 of menstruation. Female patients who initiated GnRH-a treatment 3-5 days postoperatively experienced less uterine bleeding during the first cycle of treatment.

  11. Tyrosyl radicals in dehaloperoxidase: how nature deals with evolving an oxygen-binding globin to a biologically relevant peroxidase.

    PubMed

    Dumarieh, Rania; D'Antonio, Jennifer; Deliz-Liang, Alexandria; Smirnova, Tatyana; Svistunenko, Dimitri A; Ghiladi, Reza A

    2013-11-15

    Dehaloperoxidase (DHP) from Amphitrite ornata, having been shown to catalyze the hydrogen peroxide-dependent oxidation of trihalophenols to dihaloquinones, is the first oxygen binding globin that possesses a biologically relevant peroxidase activity. The catalytically competent species in DHP appears to be Compound ES, a reactive intermediate that contains both a ferryl heme and a tyrosyl radical. By simulating the EPR spectra of DHP activated by H2O2, Thompson et al. (Thompson, M. K., Franzen, S., Ghiladi, R. A., Reeder, B. J., and Svistunenko, D. A. (2010) J. Am. Chem. Soc. 132, 17501-17510) proposed that two different radicals, depending on the pH, are formed, one located on either Tyr-34 or Tyr-28 and the other on Tyr-38. To provide additional support for these simulation-based assignments and to deduce the role(s) that tyrosyl radicals play in DHP, stopped-flow UV-visible and rapid-freeze-quench EPR spectroscopic methods were employed to study radical formation in DHP when three tyrosine residues, Tyr-28, Tyr-34, and Tyr-38, were replaced either individually or in combination with phenylalanines. The results indicate that radicals form on all three tyrosines in DHP. Evidence for the formation of DHP Compound I in several tyrosine mutants was obtained. Variants that formed Compound I showed an increase in the catalytic rate for substrate oxidation but also an increase in heme bleaching, suggesting that the tyrosines are necessary for protecting the enzyme from oxidizing itself. This protective role of tyrosines is likely an evolutionary adaptation allowing DHP to avoid self-inflicted damage in the oxidative environment.

  12. The innate oxygen dependant immune pathway as a sensitive parameter to predict the performance of biological graft materials.

    PubMed

    Bryan, Nicholas; Ashwin, Helen; Smart, Neil; Bayon, Yves; Scarborough, Nelson; Hunt, John A

    2012-09-01

    Clinical performance of a biomaterial is decided early after implantation as leukocytes interrogate the graft throughout acute inflammation. High degrees of leukocyte activation lead to poor material/patient compliance, accelerated degeneration and graft rejection. A number reactive oxygen species (ROS) are released by leukocytes throughout their interaction with a material, which can be used as a sensitive measure of leukocyte activation. The aim of this study was to compare leukocyte activation by commercially available biologic surgical materials and define the extent manufacturing variables influence down-stream ROS response. Chemiluminescence assays were performed using modifications to a commercially available kit (Knight Scientific, UK). Whole blood was obtained from 4 healthy human adults at 7 day intervals for 4 weeks, combined with Adjuvant K, Pholasin (a highly sensitive ROS excitable photoprotein) and biomaterial, and incubated for 60 min with continuous chemiluminescent measurements. Leukocyte ROS inducers fMLP and PMA were added as controls. Xeno- and allogeneic dermal and small intestinal submucosal (SIS) derived biomaterials were produced commercially (Surgisis Biodesign™, Alloderm(®), Strattice(®)Firm & Pliable & Permacol™) or fabricated in house to induce variations in decellularisation and cross-linking. Statistics were performed using Waller-Duncan post hoc ranking. Materials demonstrated significant differences in leukocyte activation as a function of decellularisation reagent and tissue origin. The data demonstrated SIS was significantly more pro-inflammatory than dermis. Additionally it was deduced that SDS during decellularisation induced pro-inflammatory changes to dermal materials. Furthermore, it was possible to conclude inter-patient variation in leukocyte response. The in vitro findings were validated in vivo which confirmed the chemiluminescence observations, highlighting the potential for translation of this technique as a

  13. Endogenous Generation of Singlet Oxygen and Ozone in Human and Animal Tissues: Mechanisms, Biological Significance, and Influence of Dietary Components

    PubMed Central

    2016-01-01

    Recent studies have shown that exposing antibodies or amino acids to singlet oxygen results in the formation of ozone (or an ozone-like oxidant) and hydrogen peroxide and that human neutrophils produce both singlet oxygen and ozone during bacterial killing. There is also mounting evidence that endogenous singlet oxygen production may be a common occurrence in cells through various mechanisms. Thus, the ozone-producing combination of singlet oxygen and amino acids might be a common cellular occurrence. This paper reviews the potential pathways of formation of singlet oxygen and ozone in vivo and also proposes some new pathways for singlet oxygen formation. Physiological consequences of the endogenous formation of these oxidants in human tissues are discussed, as well as examples of how dietary factors may promote or inhibit their generation and activity. PMID:27042259

  14. Endogenous Generation of Singlet Oxygen and Ozone in Human and Animal Tissues: Mechanisms, Biological Significance, and Influence of Dietary Components.

    PubMed

    Onyango, Arnold N

    2016-01-01

    Recent studies have shown that exposing antibodies or amino acids to singlet oxygen results in the formation of ozone (or an ozone-like oxidant) and hydrogen peroxide and that human neutrophils produce both singlet oxygen and ozone during bacterial killing. There is also mounting evidence that endogenous singlet oxygen production may be a common occurrence in cells through various mechanisms. Thus, the ozone-producing combination of singlet oxygen and amino acids might be a common cellular occurrence. This paper reviews the potential pathways of formation of singlet oxygen and ozone in vivo and also proposes some new pathways for singlet oxygen formation. Physiological consequences of the endogenous formation of these oxidants in human tissues are discussed, as well as examples of how dietary factors may promote or inhibit their generation and activity.

  15. Responses of the lower thermospheric temperature to the 9 day and 13.5 day oscillations of recurrent geomagnetic activity

    NASA Astrophysics Data System (ADS)

    Jiang, Guoying; Wang, Wenbin; Xu, Jiyao; Yue, Jia; Burns, Alan G.; Lei, Jiuhou; Mlynczak, Martin G.; Rusell, James M.

    2014-06-01

    Responses of the lower thermospheric temperature to the 9 day and 13.5 day oscillations of recurrent geomagnetic activity and solar EUV radiation have been investigated using neutral temperature data observed by the TIMED/SABER (Thermosphere Ionosphere Mesosphere Energetics and Dynamics/Sounding of the Atmosphere using Broadband Emission Radiometry) instrument and numerical experiments by the NCAR-TIME-GCM (National Center for Atmospheric Research-thermosphere-ionosphere-mesosphere electrodynamics-general circulation model). The TIMED/SABER data analyzed were for the period from 2002 to 2007 during the declining phase of solar cycle 23. The observations show that the zonal mean temperature in the lower thermosphere oscillated with periods of near 9 and 13.5 days in the height range of 100-120 km. These oscillations were more strongly correlated with the recurrent geomagnetic activity than with the solar EUV variability of the same periods. The 9 day and 13.5 day oscillations of lower thermospheric temperature had greater amplitudes at high latitudes than at low latitudes; they also had larger amplitudes at higher altitudes, and the oscillations could penetrate down to ~105 km, depending on the strength of the recurrent geomagnetic activity for a particular time period. The data further show that the periodic responses of the lower thermospheric temperature to recurrent geomagnetic activity were different in the two hemispheres. In addition, numerical experiments have been carried out using the NCAR-TIME-GCM to investigate the causal relationship between the temperature oscillations and the geomagnetic activity and solar EUV variations of the same periods. Model simulations showed the same periodic oscillations as those seen in the observations when the real geomagnetic activity index, Kp, was used to drive the model. These numerical results show that recurrent geomagnetic activity is the main cause of the 9 day and 13.5 day variations in the lower thermosphere

  16. Toward Relatively General and Accurate Quantum Chemical Predictions of Solid-State (17)O NMR Chemical Shifts in Various Biologically Relevant Oxygen-Containing Compounds.

    PubMed

    Rorick, Amber; Michael, Matthew A; Yang, Liu; Zhang, Yong

    2015-09-03

    Oxygen is an important element in most biologically significant molecules, and experimental solid-state (17)O NMR studies have provided numerous useful structural probes to study these systems. However, computational predictions of solid-state (17)O NMR chemical shift tensor properties are still challenging in many cases, and in particular, each of the prior computational works is basically limited to one type of oxygen-containing system. This work provides the first systematic study of the effects of geometry refinement, method, and basis sets for metal and nonmetal elements in both geometry optimization and NMR property calculations of some biologically relevant oxygen-containing compounds with a good variety of XO bonding groups (X = H, C, N, P, and metal). The experimental range studied is of 1455 ppm, a major part of the reported (17)O NMR chemical shifts in organic and organometallic compounds. A number of computational factors toward relatively general and accurate predictions of (17)O NMR chemical shifts were studied to provide helpful and detailed suggestions for future work. For the studied kinds of oxygen-containing compounds, the best computational approach results in a theory-versus-experiment correlation coefficient (R(2)) value of 0.9880 and a mean absolute deviation of 13 ppm (1.9% of the experimental range) for isotropic NMR shifts and an R(2) value of 0.9926 for all shift-tensor properties. These results shall facilitate future computational studies of (17)O NMR chemical shifts in many biologically relevant systems, and the high accuracy may also help the refinement and determination of active-site structures of some oxygen-containing substrate-bound proteins.

  17. Configuration of the Hemoglobin Oxygen Dissociation Curve Demystified: A Basic Mathematical Proof for Medical and Biological Sciences Undergraduates

    ERIC Educational Resources Information Center

    Leow, Melvin Khee-Shing

    2007-01-01

    The oxygen dissociation curve (ODC) of hemoglobin (Hb) has been widely studied and mathematically described for nearly a century. Numerous mathematical models have been designed to predict with ever-increasing accuracy the behavior of oxygen transport by Hb in differing conditions of pH, carbon dioxide, temperature, Hb levels, and…

  18. Effectiveness of short-course therapy (5 days) with grepafloxacin in the treatment of acute bacterial exacerbations of chronic bronchitis.

    PubMed

    DeAbate, C A; Bettis, R; Munk, Z M; Fleming, H; Munn, N J; Riffer, E; Bagby, B; Giguere, G; Collins, J J

    1999-01-01

    Three hundred eighty-nine patients were enrolled in a double-masked, multicenter, randomized clinical trial comparing the clinical and bacteriologic efficacies and safety of a 5-day course (n = 195) versus a 10-day course (n = 194) of grepafloxacin 400 mg once daily in the treatment of acute bacterial exacerbations of chronic bronchitis (ABECB). Patients in the 5-day treatment group received placebo on days 6 through 10. Bacteriologic assessments were based on cultures of sputum specimens obtained before and, when possible, during and after treatment. Organisms were isolated from the pretreatment sputum specimens of 332 of 388 (86%) patients, the primary pathogens being Haemophilus parainfluenzae, Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis, and Staphylococcus aureus (29%, 19%, 4%, 5%, and 5% of isolates, respectively). Among isolates tested for beta-lactamase production, results were positive in 25% of H influenzae isolates and 90% of M catarrhalis isolates. Forty-two percent of S pneumoniae isolates demonstrated reduced susceptibility (intermediate or high-level resistance) to penicillin. A satisfactory clinical outcome (cure or improvement) was achieved in 83% (128 of 155) and 81% (122 of 150) of clinically evaluable patients treated with grepafloxacin for 5 or 10 days, respectively. Pathogens were eradicated or presumed eradicated in 77% (106 of 138) and 80% (98 of 123) of bacteriologically evaluable patients treated with grepafloxacin for 5 or 10 days, respectively. The 2 treatment groups were equivalent with respect to both clinical and bacteriologic efficacy, and no statistically significant differences in the incidence of drug-related adverse events were seen between the 2 groups. Substantial symptom relief was evident with both treatment regimens by the first during-treatment measurement, which occurred between days 3 through 5. These results indicate that treatment with 400 mg grepafloxacin once daily for 5 days is as well

  19. Daily Profiles of Fibrinogen Metabolism for 5 Days Following Hemorrhage and Lactated Ringer’s Resuscitation in Pigs

    DTIC Science & Technology

    2012-01-01

    DAILY PROFILES OF FIBRINOGEN METABOLISM FOR 5 DAYS FOLLOWING HEMORRHAGE AND LACTATED RINGER’S RESUSCITATION IN PIGS Wenjun Z. Martini , Kevin K. Chung...for measurement of mean arterial pressure 605 SHOCK, Vol. 37, No. 6, pp. 605 610, 2012 Address reprint requests to Wenjun Z. Martini , PhD, The US...Ringerâs Resuscitation in Pigs 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Martini W. Z., Chung K. K., Dubick M. A

  20. Evaluation of platelets prepared by apheresis and stored for 5 days. In vitro and in vivo studies

    SciTech Connect

    Shanwell, A.; Gulliksson, H.; Berg, B.K.; Jansson, B.A.; Svensson, L.A.

    1989-11-01

    To evaluate the effect of storage on apheresis platelets collected with a closed-system blood cell separator, an in vitro investigation was performed, with measurements of pH, lactate, ATP, the ratio of ATP to the total adenine nucleotide content, and adenylate kinase. Unmodified apheresis platelets and apheresis platelets with plasma added were compared with conventional platelets stored in PL-1240 or PL-732 plastic containers. During 6 days of storage, there were similar changes in all variables with one exception: the extracellular activity of adenylate kinase was lower in apheresis platelets with plasma than in the other three groups (p less than 0.01). In vivo studies were carried out with 111Indium-labeled autologous platelets in eight volunteers. Apheresis platelets with 100 mL of plasma added were stored in two 1000-mL containers (PL-732) at 22 degrees C during agitation. Platelets from one of the containers were labeled with 111Indium and transfused into the volunteer within 24 hours. Platelets from the other container were labeled after 5 days of storage and transfused into the same donor. There were no significant differences between apheresis platelets stored for 1 day and those stored for 5 days: the mean percentage of recovery was 58.4 and 57.6 percent, t1/2 was 69 and 67 hours, and the survival time was 5.5 and 5.6 days, respectively.

  1. Synthesis, characterization and biological relevance of some metal (II) complexes with oxygen, nitrogen and oxygen (ONO) donor Schiff base ligand derived from thiazole and 2-hydroxy-1-naphthaldehyde

    NASA Astrophysics Data System (ADS)

    Nagesh, G. Y.; Mruthyunjayaswamy, B. H. M.

    2015-04-01

    The novel Schiff base ligand 2-((2-hydroxynaphthalen-1-yl)methylene)-N-(4-phenylthiazol-2-yl)hydrazinecarboxamide (L) obtained by the condensation of N-(4-phenylthiazol-2-yl)hydrazinecarboxamide with 2-hydroxy-1-naphthaldehyde and its newly synthesized Cu(II), Co(II), Ni(II), Zn(II) and Cd(II) complexes have been characterized by microanalysis, molar conductance, IR, 1H NMR, ESI-mass, UV-Visible, TGA/DTA, ESR and powder X-ray diffraction data to explicate their structures. The IR results confirmed the tridentate binding of the ligand involving oxygen atom of amide carbonyl, azomethine nitrogen and naphthol oxygen. 1H NMR spectral data of the ligand (L) and its Zn(II) complex agreed well with the proposed structures. Thermogravimetric studies for Cu(II) and Ni(II) complexes indicated the presence of coordinated water molecules and the final product is the metal oxide. In order to appraise the effect of antimicrobial activity of metal ions upon chelation, the newly synthesized ligand and its metal complexes were screened for their antimicrobial activity by minimum inhibitory concentration (MIC) method. The DNA cleavage activities were studied using plasmid DNA pBR322 (Bangal re Genei, Bengaluru, Cat. No 105850) as a target molecule by agarose gel electrophoresis method. The brine shrimp bioassay was also carried out to study the in vitro cytotoxicity properties against Artemia salina. Furthermore, the antioxidant activity were determined in vitro by reduction of 1,1-diphenyl-2-picryl hydrazyl (DPPH). The ligand exhibited better in vitro-antioxidant activity than its metal complexes.

  2. Efficacy and safety of 3 versus 5 days of meloxicam as an analgesic for feline onychectomy and sterilization

    PubMed Central

    Ingwersen, Walt; Fox, Ronald; Cunningham, Gail; Winhall, Martha

    2012-01-01

    Three- or 5-day courses of meloxicam [0.2 mg/kg body weight (BW) subcutaneously pre- or postoperatively on Day 1 followed by 0.05 mg/kg BW, PO per day thereafter] were assessed for analgesic efficacy and safety in 50 client-owned cats undergoing onychectomy and sterilization. Primary outcome parameters were analgesia score, gait/lameness score, and need for rescue analgesia assessed at times 0, 1, 4, 7, 24, 28, 35, 48, 52, 57 hours and on Day 5. Packed cell volume/total solids and serum biochemistry were assessed at time 0 and Days 3 and 5. There were no differences in efficacy and safety parameters regardless of the treatment protocol employed and no cat required rescue analgesia. The patients that received meloxicam preoperatively had statistically better gait/lameness scores than those that received meloxicam postoperatively, supporting the principle of preemptive analgesia. PMID:22942440

  3. Efficacy and safety of 3 versus 5 days of meloxicam as an analgesic for feline onychectomy and sterilization.

    PubMed

    Ingwersen, Walt; Fox, Ronald; Cunningham, Gail; Winhall, Martha

    2012-03-01

    Three- or 5-day courses of meloxicam [0.2 mg/kg body weight (BW) subcutaneously pre- or postoperatively on Day 1 followed by 0.05 mg/kg BW, PO per day thereafter] were assessed for analgesic efficacy and safety in 50 client-owned cats undergoing onychectomy and sterilization. Primary outcome parameters were analgesia score, gait/lameness score, and need for rescue analgesia assessed at times 0, 1, 4, 7, 24, 28, 35, 48, 52, 57 hours and on Day 5. Packed cell volume/total solids and serum biochemistry were assessed at time 0 and Days 3 and 5. There were no differences in efficacy and safety parameters regardless of the treatment protocol employed and no cat required rescue analgesia. The patients that received meloxicam preoperatively had statistically better gait/lameness scores than those that received meloxicam postoperatively, supporting the principle of preemptive analgesia.

  4. A 2l-He hybrid cryostat with 5 days holdtime for a 690 GHz InSb-bolometer

    NASA Astrophysics Data System (ADS)

    Woestenburg, E. E. M.; Casse, J. L.

    The design and construction of a 2-liter helium cryostat are described, using a closed cycle refrigerator to cool the cryostat radiation shields. A 5-day hold-time at 4.2 K has been achieved with this configuration. The cryostat is being used to cool a Schottky diode mixer at 350 GHz and an InSb bolometer at 690 GHz to 20 K and 4.2 K, respectively. The heat load on the 4 K cold station has been minimized using a thermal model of the cryostat, partly developed on the basis of measurements on the real cryostat. Using the model, insight was gained into the importance of various heat loads, permitting improvements in the original cryostat.

  5. Discovery of a Similar to 5 Day Characteristic Timescale in the Kepler Power Spectrum of Zw 229-15

    NASA Technical Reports Server (NTRS)

    Edelson, R.; Vaughan, S.; Malkan, M.; Kelly, B. C.; Smith, K. L.; Boyd, P. T.; Mushotzky, R.

    2014-01-01

    We present time series analyses of the full Kepler dataset of Zw 229- 15. This Kepler light curve- with a baseline greater than three years, composed of virtually continuous, evenly sampled 30-minute measurements - is unprecedented in its quality and precision. We utilize two methods of power spectral analysis to investigate the optical variability and search for evidence of a bend frequency associated with a characteristic optical variability timescale. Each method yields similar results. The first interpolates across data gaps to use the standard Fourier periodogram. The second, using the CARMA-based time-domain modeling technique of Kelly et al., does not need evenly-sampled data. Both methods find excess power at high frequencies that may be due to Kepler instrumental effects. More importantly both also show strong bends (delta alpha is approx. 2) at timescales of approx. 5 days, a feature similar to those seen in the X-ray PSDs of AGN but never before in the optical. This observed approx. 5 day timescale may be associated with one of several physical processes potentially responsible for the variability. A plausible association could be made with light -crossing, dynamical or thermal timescales, depending on the assumed value of the accretion disk size and on unobserved disk parameters such as alpha and H¬R. This timescale is not consistent with the viscous timescale, which would be years in a approx. 10(exp7) solar mass AGN such as Zw 229- 15. However there must be a second bend on long (& 1 year) timescales, and that feature could be associated with the viscous timescale.

  6. Discovery of a ∼5 day characteristic timescale in the Kepler power spectrum of Zw 229–15

    SciTech Connect

    Edelson, R.; Smith, K. L.; Mushotzky, R.; Vaughan, S.; Malkan, M.; Kelly, B. C.; Boyd, P. T.

    2014-11-01

    We present time series analyses of the full Kepler data set of Zw 229–15. This Kepler light curve—with a baseline greater than 3 yr, composed of virtually continuous, evenly sampled 30 minute measurements—is unprecedented in its quality and precision. We utilize two methods of power spectral analysis to investigate the optical variability and search for evidence of a bend frequency associated with a characteristic optical variability timescale. Each method yields similar results. The first interpolates across data gaps to use the standard Fourier periodogram. The second, using the CARMA-based time-domain modeling technique of Kelly et al., does not need evenly sampled data. Both methods find excess power at high frequencies that may be due to Kepler instrumental effects. More importantly, both also show strong bends (Δα ∼ 2) at timescales of ∼5 days, a feature similar to those seen in the X-ray power spectral densities of active galactic nuclei (AGNs) but never before in the optical. This observed ∼5 day timescale may be associated with one of several physical processes potentially responsible for the variability. A plausible association could be made with light-crossing dynamical or thermal timescales depending on the assumed value of the accretion disk size and on unobserved disk parameters such as α and H/R. This timescale is not consistent with the viscous timescale, which would be years in a ∼10{sup 7} M {sub ☉} AGN such as Zw 229–15. However, there must be a second bend on long (≳ 1 yr) timescales and that feature could be associated with the viscous timescale.

  7. Biological oxygen sensing via two-photon absorption by an Ir(III) complex using a femtosecond fiber laser

    NASA Astrophysics Data System (ADS)

    Moritomo, Hiroki; Fujii, Akinari; Suzuki, Yasutaka; Yoshihara, Toshitada; Tobita, Seiji; Kawamata, Jun

    2016-09-01

    Near-infrared two-photon absorption of the phosphorescent Ir(III) complex (2,4-pentanedionato-κO 2,κO 4)bis[2-(6-phenanthridinyl-κN)benzo[b]thien-3-yl-κC]iridium (BTPHSA) was characterized. It exhibited a 800-1200 nm two-photon absorption band, and thus could be electronically excited by 1030-nm femtosecond Ti:sapphire and Yb-doped fiber lasers. By using BTPHSA, oxygen concentrations in human embryonic kidney 293 (HEK293) cells were imaged. These results demonstrate two-photon oxygen sensing of live tissues via easily operable excitation sources.

  8. Simultaneous chemical oxygen demand removal, methane production and heavy metal precipitation in the biological treatment of landfill leachate using acid mine drainage as sulfate resource.

    PubMed

    Li, Yu-Long; Wang, Jin; Yue, Zheng-Bo; Tao, Wei; Yang, Hai-Bin; Zhou, Yue-Fei; Chen, Tian-Hu

    2017-03-06

    Biological treatment played an important role in the treatment of landfill leachate. In the current study, acid mine drainage (AMD) was used as a source of sulfate to strengthen the anaerobic treatment of landfill leachate. Effects of chemical oxygen demand (COD) and SO4(2-) mass concentration ratio on the decomposition of organic matter, methane production and sulfate reduction were investigated and the microbial community was analyzed using the high throughout methods. Results showed that high removal efficiency of COD, methane production and heavy metal removal was achieved when the initial COD/SO4(2-) ratio (based on mass) was set at 3.0. The relative abundance of anaerobic hydrogen-producing bacteria (Candidatus Cloacamonas) in the experimental group with the addition of AMD was significantly increased compared to the control. Abundance of hydrogenotrophic methanogens of Methanosarcina and Methanomassiliicoccus was increased. Results confirmed that AMD could be used as sulfate resource to strengthen the biological treatment of landfill leachate.

  9. Oxygen Sensing and Homeostasis

    PubMed Central

    Semenza, Gregg L.

    2015-01-01

    The discovery of carotid bodies as sensory receptors for detecting arterial blood oxygen levels, and the identification and elucidation of the roles of hypoxia-inducible factors (HIFs) in oxygen homeostasis have propelled the field of oxygen biology. This review highlights the gas-messenger signaling mechanisms associated with oxygen sensing, as well as transcriptional and non-transcriptional mechanisms underlying the maintenance of oxygen homeostasis by HIFs and their relevance to physiology and pathology. PMID:26328879

  10. Lipid droplet dynamics and insulin sensitivity upon a 5-day high-fat diet in Caucasians and South Asians.

    PubMed

    Gemmink, Anne; Bakker, Leontine E H; Guigas, Bruno; Kornips, Esther; Schaart, Gert; Meinders, A Edo; Jazet, Ingrid M; Hesselink, Matthijs K C

    2017-02-14

    A 5-day High-Fat High-Calorie diet (HFHC-diet) reduces insulin-stimulated glucose disposal (Rd) in South Asian, but not Caucasian healthy lean males. We aimed to investigate if differences in myocellular lipid handling are underlying this differential response. A two-step hyperinsulinemic-euglycemic clamp and muscle biopsies were performed in 12 healthy lean Caucasian and South Asian males (BMI < 25 kg/m(2), 19-25 years) before and after a 5-day HFHC-diet (regular diet + 375 mL cream/day; 1275 kcal/day; 94% fat). Triglyceride extractions and Western Blots for lipid droplet and mitochondrial proteins were performed. Intramyocellular lipid content and HFHC-diet response were similar between ethnicities (group effect: P = 0.094; diet effect: +~30%, P = 0.044). PLIN5 protein content increased upon the HFHC-diet (P = 0.031) and tended to be higher in South Asians (0.87 ± 0.42 AU vs. 1.35 ± 0.58 AU, P = 0.07). 4-HNE tended to increase in South Asians upon the HFHC-diet (interaction effect: P = 0.057). In Caucasians ΔPLIN5 content correlated with ΔRd (Caucasians: r = 0.756, P = 0.011; South Asians: r = -0.085, P = 0.816), while in South Asians Δ4-HNE associated with ΔPLIN5 content (Caucasians: r = 0.312, P = 0.380; South Asians: r = 0.771, P = 0.003). These data indicate that in Caucasians, PLIN5 may be protective against HFHC-diet induced insulin resistance, which for reasons not yet understood is not observed in South Asians, who possess increased lipid peroxidation levels.

  11. Lipid droplet dynamics and insulin sensitivity upon a 5-day high-fat diet in Caucasians and South Asians

    PubMed Central

    Gemmink, Anne; Bakker, Leontine E. H.; Guigas, Bruno; Kornips, Esther; Schaart, Gert; Meinders, A. Edo; Jazet, Ingrid M.; Hesselink, Matthijs K. C.

    2017-01-01

    A 5-day High-Fat High-Calorie diet (HFHC-diet) reduces insulin-stimulated glucose disposal (Rd) in South Asian, but not Caucasian healthy lean males. We aimed to investigate if differences in myocellular lipid handling are underlying this differential response. A two-step hyperinsulinemic-euglycemic clamp and muscle biopsies were performed in 12 healthy lean Caucasian and South Asian males (BMI < 25 kg/m2, 19–25 years) before and after a 5-day HFHC-diet (regular diet + 375 mL cream/day; 1275 kcal/day; 94% fat). Triglyceride extractions and Western Blots for lipid droplet and mitochondrial proteins were performed. Intramyocellular lipid content and HFHC-diet response were similar between ethnicities (group effect: P = 0.094; diet effect: +~30%, P = 0.044). PLIN5 protein content increased upon the HFHC-diet (P = 0.031) and tended to be higher in South Asians (0.87 ± 0.42 AU vs. 1.35 ± 0.58 AU, P = 0.07). 4-HNE tended to increase in South Asians upon the HFHC-diet (interaction effect: P = 0.057). In Caucasians ΔPLIN5 content correlated with ΔRd (Caucasians: r = 0.756, P = 0.011; South Asians: r = −0.085, P = 0.816), while in South Asians Δ4-HNE associated with ΔPLIN5 content (Caucasians: r = 0.312, P = 0.380; South Asians: r = 0.771, P = 0.003). These data indicate that in Caucasians, PLIN5 may be protective against HFHC-diet induced insulin resistance, which for reasons not yet understood is not observed in South Asians, who possess increased lipid peroxidation levels. PMID:28195217

  12. Configuration of the hemoglobin oxygen dissociation curve demystified: a basic mathematical proof for medical and biological sciences undergraduates.

    PubMed

    Leow, Melvin Khee-Shing

    2007-06-01

    The oxygen dissociation curve (ODC) of hemoglobin (Hb) has been widely studied and mathematically described for nearly a century. Numerous mathematical models have been designed to predict with ever-increasing accuracy the behavior of oxygen transport by Hb in differing conditions of pH, carbon dioxide, temperature, Hb levels, and 2,3-diphosphoglycerate concentrations that enable their applications in various clinical situations. The modeling techniques employed in many existing models are notably borrowed from advanced and highly sophisticated mathematics that are likely to surpass the comprehensibility of many medical and bioscience students due to the high level of "mathematical maturity" required. It is, however, a worthy teaching point in physiology lectures to illustrate in simple mathematics the fundamental reason for the crucial sigmoidal configuration of the ODC such that the medical and bioscience undergraduates can readily appreciate it, which is the objective of this basic dissertation.

  13. Effects of endurance training on endocrine response to physical exercise after 5 days of bed rest in healthy male subjects.

    PubMed

    Koska, Juraj; Ksinantová, Lucia; Kvetnanský, Richard; Hamar, Dusan; Martinkovic, Miroslav; Vigas, Milan

    2004-06-01

    The study was designed to evaluate how a bout of endurance training (ET) influences the endocrine response after head-down bed rest (HDBR). Eleven healthy males completed the study, which consisted of a 6-wk ET followed by 5 days of -6 degrees head-down HDBR. Treadmill exercise at 80% of pretraining maximal aerobic capacity (VO(2max)) was performed before and after ET as well as after HDBR. ET increased VO(2max) by 13%. The response of norepinephrine was attenuated after ET and exaggerated after HDBR (P < 0.001). The differences in epinephrine responses were not statistically significant. The responses of cortisol and plasma renin activity (PRA) were unchanged after ET and were enhanced after HDBR (P < 0.001). The response of growth hormone after HDBR was reduced (P < 0.05). Only the change in cortisol response was associated with the increment of VO(2max) after ET (r = 0.68, P < 0.01). Endurance training failed to completely prevent changes in endocrine responses seen after HDBR. Improvement of physical fitness was associated with an enhancement of the cortisol response to exercise following the period of bed rest.

  14. Influence of CeO2 NPs on biological phosphorus removal and bacterial community shifts in a sequencing batch biofilm reactor with the differential effects of molecular oxygen.

    PubMed

    Xu, Yi; Wang, Chao; Hou, Jun; Wang, Peifang; You, Guoxiang; Miao, Lingzhan; Lv, Bowen; Yang, Yangyang

    2016-11-01

    The effects of CeO2 nanoparticles (CeO2 NPs) on a sequencing batch biofilm reactor (SBBR) with established biological phosphorus (P) removal were investigated from the processes of anaerobic P release and aerobic P uptake. At low concentration (0.1mg/L), no significant impact was observed on total phosphorus (TP) removal after operating for 8h. However, at a concentration of 20mg/L, TP removal efficiency decreased from 83.68% to 55.88% and 16.76% when the CeO2 NPs were added at the beginning of the anaerobic and aerobic periods, respectively. Further studies illustrated that the inhibition of the specific P release rate was caused by the reversible states of Ce(3+) and Ce(4+), which inhibited the activity of exopolyphosphatase (PPX) and transformation of poly-β-hydoxyalkanoates (PHA) and glycogen, as well as the uptake of volatile fatty acids (VFAs). The decrease in the specific P uptake rate was mainly attributed to the significantly suppressed energy generation and decreased abundance of Burkholderia caused by excess reactive oxygen species. The removal of chemical oxygen demand (COD) was not influenced by CeO2 NPs under aerobic conditions, due to the increased abundance of Acetobacter and Acidocella after exposure. The inhibitory effects of CeO2 NPs with molecular oxygen were reduced after anaerobic exposure due to the enhanced particle size and the presence of Ce(3+).

  15. Benthic biological and biogeochemical patterns and processes across an oxygen minimum zone (Pakistan margin, NE Arabian Sea)

    NASA Astrophysics Data System (ADS)

    Cowie, Gregory L.; Levin, Lisa A.

    2009-03-01

    Oxygen minimum zones (OMZs) impinging on continental margins present sharp gradients ideal for testing environmental factors thought to influence C cycling and other benthic processes, and for identifying the roles that biota play in these processes. Here we introduce the objectives and initial results of a multinational research program designed to address the influences of water depth, the OMZ (˜150-1300 m), and organic matter (OM) availability on benthic communities and processes across the Pakistan Margin of the Arabian Sea. Hydrologic, sediment, and faunal characterizations were combined with in-situ and shipboard experiments to quantify and compare biogeochemical processes and fluxes, OM burial efficiency, and the contributions of benthic communities, across the OMZ. In this introductory paper, we briefly review previous related work in the Arabian Sea, building the rationale for integrative biogeochemical and ecological process studies. This is followed by a summary of individual volume contributions and a brief synthesis of results. Five primary stations were studied, at 140, 300, 940, 1200 and 1850 m water depth, with sampling in March-May (intermonsoon) and August-October (late-to-postmonsoon) 2003. Taken together, the contributed papers demonstrate distinct cross-margin gradients, not only in oxygenation and sediment OM content, but in benthic community structure and function, including microbial processes, the extent of bioturbation, and faunal roles in C cycling. Hydrographic studies demonstrated changes in the intensity and extent of the OMZ during the SW monsoon, with a shoaling of the upper OMZ boundary that engulfed the previously oxygenated 140-m site. Oxygen profiling and microbial process rate determinations demonstrated dramatic differences in oxygen penetration and consumption across the margin, and in the relative importance of anaerobic processes, but surprisingly little seasonal change. A broad maximum in sediment OM content occurred on

  16. Recalcitrant organic compounds (chemical oxygen demand sources) in biologically treated pulp and paper mill effluents: Their fate and environmental impact in receiving waters

    SciTech Connect

    Archibald, F.; Roy-Arcand, L.; Methot, M.; Valeanu, L.

    1998-11-01

    Most North American pulp and paper mills now biologically treat (biotreat) their liquid effluent. However, treated water still contains effluent-derived recalcitrant organic material (EROM), measured as chemical oxygen demand (COD), for which emission limits exist in Europe and are being considered in the US. Production of microbially resistant, dissolved natural organic material (NOM) typically found in Canadian stream and lake waters occurs slowly under gentle conditions, while mill EROM is generated from lignocellulosics by faster and harsher processes. Similarity of the environmental effects of NOM and pulp and paper mill EROM are examined. Changes occurring over 4 months in biologically treated effluent from two modern Canadian mills and lake NOM when sealed in gas- and light-permeable bags and placed in a pristine Quebec lake are reported. Addition of microbial co-metabolites significantly improved the dark mineralization of organochlorines surviving mill biological treatment. Mill EROM was light sensitive, nonacutely toxic in the Microtox assay, and similar to NOM in the surrounding lake in most bulk properties. There was no evidence to suggest that placing specific limits on mill EROM (COD) emissions would be environmentally beneficial.

  17. Low Pressure Radio-Frequency Oxygen Plasma Induced Oxidation of Titanium – Surface Characteristics and Biological Effects

    PubMed Central

    Tseng, Wan-Yu; Hsu, Sheng-Hao; Huang, Chieh-Hsiun; Tu, Yu-Chieh; Tseng, Shao-Chin; Chen, Hsuen-Li; Chen, Min-Huey; Su, Wei-Fang; Lin, Li-Deh

    2013-01-01

    Objective This research was designed to investigate the effects of low pressure radio-frequency (RF) oxygen plasma treatment (OPT) on the surface of commercially pure titanium (CP-Ti) and Ti6Al4V. Surface topography, elemental composition, water contact angle, cell viability, and cell morphology were surveyed to evaluate the biocompatibility of titanium samples with different lengths of OP treating time. Materials and Methods CP-Ti and Ti6Al4V discs were both classified into 4 groups: untreated, treated with OP generated by using oxygen (99.98%) for 5, 10, and 30 min, respectively. After OPT on CP-Ti and Ti6Al4V samples, scanning probe microscopy, X-ray photoelectron spectrometry (XPS), and contact angle tests were conducted to determine the surface topography, elemental composition and hydrophilicity, respectively. The change of surface morphology was further studied using sputtered titanium on silicon wafers. 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay and F-actin immunofluorescence stain were performed to investigate the viability and spreading behavior of cultivated MG-63 cells on the samples. Results The surface roughness was most prominent after 5 min OPT in both CP-Ti and Ti6Al4V, and the surface morphology of sputtered Ti sharpened after the 5 min treatment. From the XPS results, the intensity of Ti°, Ti2+, and Ti3+ of the samples’ surface decreased indicating the oxidation of titanium after OPT. The water contact angles of both CP-Ti and Ti6Al4V were increased after 5 min OPT. The results of MTT assay demonstrated MG-63 cells proliferated best on the 5 min OP treated titanium sample. The F-actin immunofluorescence stain revealed the cultivated cell number of 5 min treated CP-Ti/Ti6Al4V was greater than other groups and most of the cultivated cells were spindle-shaped. Conclusions Low pressure RF oxygen plasma modified both the composition and the morphology of titanium samples’ surface. The CP-Ti/Ti6Al4V treated with 5 min

  18. Practical use of chemical probes for reactive oxygen species produced in biological systems by γ-irradiation

    NASA Astrophysics Data System (ADS)

    Lee, Min Hee; Moon, Yu Ran; Chung, Byung Yeoup; Kim, Jae-Sung; Lee, Kang-Soo; Cho, Jae-Young; Kim, Jin-Hong

    2009-05-01

    Application of chemical probes, for detection of reactive oxygen species (ROS), was tested during γ-irradiation. The ethanol/α-(4-pyridyl-1-oxide)- N- tert-butylnitrone (4-POBN) and 3,3'-diaminobenzidine (DAB) were structurally stable enough to detect rad OH and H 2O 2, increasingly generated by γ-irradiation up to 1000 Gy. Interestingly, the production rate of H 2O 2, but not rad OH, during γ-irradiation, was significantly different between in vitro systems of lettuce and spinach. These results suggest that 4-POBN and DAB could be utilized as a semi-quantitative probe to quantify rad OH and H 2O 2, produced by γ-irradiation up to 1000 Gy.

  19. Seasonal variation in biological oxygen demand levels in the main stem of the Fraser River, British Columbia and an agriculturally impacted tributary

    NASA Astrophysics Data System (ADS)

    Gillies, S. L.; Fraser, H.; Marsh, S. J.; Peucker-Ehrenbrink, B.; Voss, B. M.; Marcotte, D.; Fanslau, J.; Epp, A.; Bennett, M.; Hanson-Carson, J.; Luymes, R.

    2012-12-01

    The Fraser River basin is one of British Columbia's most diverse and valuable ecosystems. Water levels and temperatures along the Fraser are seasonally variable, with high flow during the spring freshet and low flow during winter months. In the Fraser River, dissolved oxygen (DO) concentrations impact many aquatic species. Biological oxygen demand (BOD) measures the amount of oxygen consumed by bacteria during the decomposition of organic matter and is an indicator of water quality in freshwater environments. We compared BOD, DO, and pH during winter (November 2011) and summer (July 2012) in the main stem of the Fraser River at Fort Langley and a tributary in an agricultural area of the Fraser Valley, Nathan Creek. In November the BOD of the main stem of the Fraser River was 2.36 mg/L, pH 7.26, and DO 9.13 mg/L. BOD and DO of Nathan Creek was not significantly lower at 1.68 mg/L and DO 8.28 mg/L, however, the pH was significantly lower (p=0.001) at 6.75. In July, the Fraser River had significantly higher BOD levels than in winter at 4.43 mg/L, but no significant change in pH and DO. Nathan Creek BOD was significantly higher than it was in winter and higher than the main stem at 7.34 mg/L, with no significant change in pH and DO. There were strong seasonal differences in BOD in the Fraser River and Nathan Creek, with the highest levels seen in July. The higher BOD seen in Nathan Creek in July may be an indication of agricultural impact. Although all BOD values fell in the range of 1-8 mg/L and are considered to be relatively unpolluted.

  20. Factors affecting the performance of a single-chamber microbial fuel cell-type biological oxygen demand sensor.

    PubMed

    Yang, Gai-Xiu; Sun, Yong-Ming; Kong, Xiao-Ying; Zhen, Feng; Li, Ying; Li, Lian-Hua; Lei, Ting-Zhou; Yuan, Zhen-Hong; Chen, Guan-Yi

    2013-01-01

    Microbial fuel cells (MFCs) are devices that exploit microorganisms as biocatalysts to degrade organic matter or sludge present in wastewater (WW), and thereby generate electricity. We developed a simple, low-cost single-chamber microbial fuel cell (SCMFC)-type biochemical oxygen demand (BOD) sensor using carbon felt (anode) and activated sludge, and demonstrated its feasibility in the construction of a real-time BOD measurement system. Further, the effects of anodic pH and organic concentration on SCMFC performance were examined, and the correlation between BOD concentration and its response time was analyzed. Our results demonstrated that the SCMFC exhibited a stable voltage after 132 min following the addition of synthetic WW (BOD concentration: 200 mg/L). Notably, the response signal increased with an increase in BOD concentration (range: 5-200 mg/L) and was found to be directly proportional to the substrate concentration. However, at higher BOD concentrations (>120 mg/L) the response signal remained unaltered. Furthermore, we optimized the SCMFC using synthetic WW, and tested it with real WW. Upon feeding real WW, the BOD values exhibited a standard deviation from 2.08 to 8.3% when compared to the standard BOD5 method, thus demonstrating the practical applicability of the developed system to real treatment effluents.

  1. Serratia Secondary Metabolite Prodigiosin Inhibits Pseudomonas aeruginosa Biofilm Development by Producing Reactive Oxygen Species that Damage Biological Molecules

    PubMed Central

    Kimyon, Önder; Das, Theerthankar; Ibugo, Amaye I.; Kutty, Samuel K.; Ho, Kitty K.; Tebben, Jan; Kumar, Naresh; Manefield, Mike

    2016-01-01

    Prodigiosin is a heterocyclic bacterial secondary metabolite belonging to the class of tripyrrole compounds, synthesized by various types of bacteria including Serratia species. Prodigiosin has been the subject of intense research over the last decade for its ability to induce apoptosis in several cancer cell lines. Reports suggest that prodigiosin promotes oxidative damage to double-stranded DNA (dsDNA) in the presence of copper ions and consequently leads to inhibition of cell-cycle progression and cell death. However, prodigiosin has not been previously implicated in biofilm inhibition. In this study, the link between prodigiosin and biofilm inhibition through the production of redox active metabolites is presented. Our study showed that prodigiosin (500 μM) (extracted from Serratia marcescens culture) and a prodigiosin/copper(II) (100 μM each) complex have strong RNA and dsDNA cleaving properties while they have no pronounced effect on protein. Results support a role for oxidative damage to biomolecules by H2O2 and hydroxyl radical generation. Further, it was demonstrated that reactive oxygen species scavengers significantly reduced the DNA and RNA cleaving property of prodigiosin. P. aeruginosa cell surface hydrophobicity and biofilm integrity were significantly altered due to the cleavage of nucleic acids by prodigiosin or the prodigiosin/copper(II) complex. In addition, prodigiosin also facilitated the bactericidal activity. The ability of prodigiosinto cause nucleic acid degradation offers novel opportunities to interfere with extracellular DNA dependent bacterial biofilms. PMID:27446013

  2. Integration of pharmacokinetic and NRF2 system biology models to describe reactive oxygen species production and subsequent glutathione depletion in liver microfluidic biochips after flutamide exposure.

    PubMed

    Leclerc, Eric; Hamon, Jeremy; Legendre, Audrey; Bois, Frederic Y

    2014-10-01

    We present a systems biology analysis of rat primary hepatocytes response after exposure to 10 μM and 100 μM flutamide in liver microfluidic biochips. We coupled an in vitro pharmacokinetic (PK) model of flutamide to a system biology model of its reactive oxygen species (ROS) production and scavenging by the Nrf2 regulated glutathione production. The PK model was calibrated using data on flutamide kinetics, hydroxyflutamide and glutathione conjugates formation in microfluidic conditions. The parameters of Nrf2-related gene activities and the subsequent glutathione depletion were calibrated using microarray data from our microfluidic experiments and literature information. Following a 10 μM flutamide exposure, the model predicted a recovery time to baseline levels of glutathione (GSH) and ROS in agreement with our experimental observations. At 100 μM, the model predicted that metabolism saturation led to an important accumulation of flutamide in cells, a high ROS production and complete GSH depletion. The high levels of ROS predicted were consistent with the necrotic switch observed by transcriptomics, and the high cell mortality we had experimentally observed. The model predicted a transition between recoverable GSH depletion and deep GSH depletion at about 12.5 μM of flutamide (single perfusion exposure). Our work shows that in vitro biochip experiments can provide supporting information for complex in silico modeling including data from extra cellular and intra cellular levels. We believe that this approach can be an efficient strategy for a global integrated methodology in predictive toxicology.

  3. Determination of Biochemical Oxygen Demand of Area Waters: A Bioassay Procedure for Environmental Monitoring

    ERIC Educational Resources Information Center

    Riehl, Matthew

    2012-01-01

    A graphical method for determining the 5-day biochemical oxygen demand (BOD5) for a body of water is described. In this bioassay, students collect a sample of water from a designated site, transport it to the laboratory, and evaluate the amount of oxygen consumed by naturally occurring bacteria during a 5-day incubation period. An accuracy check,…

  4. Across-slope relations between the biological populations, the euphotic zone and the oxygen minimum layer off the coast of Oman during the southwest monsoon (August, 1994)

    NASA Astrophysics Data System (ADS)

    Herring, P. J.; Fasham, M. J. R.; Weeks, A. R.; Hemmings, J. C. P.; Roe, H. S. J.; Pugh, P. R.; Holley, S.; Crisp, N. A.; Angel, M. V.

    1998-01-01

    An area some 120×70 km off the eastern coast of Oman (containing the UK JGOFS Arabesque station) was intensively studied over a 17 day period in August 1994, with the objective of determining the relationships between the biological populations, the oxygen minimum layer and the dynamic hydrography of the euphotic zone. The outer margin of the area was delimited by a rectangle of 15 full depth CTD casts and the hydrography was further defined by two Seasoar surveys within the box. Midwater trawls were used to sample the populations at three stations, oceanic, slope and shelf edge respectively. Day and night samples of macroplankton and micronekton were taken at each station to determine the extent of diel vertical migration and the effect of the hypoxic region on these migrations. Concurrent ADCP data were used to follow the migrations and spatial changes in real time. Despite the limited area studied the patterns of upwelling and their temporal and spatial changes were complex. Coastal upwelling was observed directly only at the southwestern edge of the area during both Seasoar surveys. Persian Gulf Water was a consistent but spatially discrete feature of the region at depths of 200-300 m. Arabian Sea Surface Water was present at the eastern margin of the first survey. Between these two water masses was a large area with small horizontal gradients and variable silicate and chlorophyll levels. Satellite data suggest that this water may have been advected as a filament from a more northerly coastal source. Very marked changes took place in the hydrography and in the phytoplankton composition and abundance at the reference station at 19°N 59°E over the 16 day period between visits. The highest biomass of plankton and micronekton (expressed as wet volume or as carbon) occurred in the upper 100 m, closely correlated with the relatively high oxygen levels at these depths. Gelatinous animals predominated in these layers, with additional swarms of swimming crabs. Quite

  5. Comparison of the effects of adenine-ribose with adenosine for maintenance of ATP concentrations in 5-day hypothermically perfused dog kidneys.

    PubMed

    McAnulty, J F; Southard, J H; Belzer, F O

    1988-10-01

    The quality of preservation of kidneys is dependent upon a number of factors, one of which may be the concentration of adenine nucleotides in the tissue during long-term perfusion preservation. In this study we have investigated how adenine (5 mM) and ribose (5 mM) in combination affect the concentration of adenine nucleotides in dog kidney cortical tissue after 5 days of continuous hypothermic perfusion preservation. These results were compared to kidneys perfused with adenosine and without any added purine precursors of adenine nucleotide synthesis. Additionally, we investigated how these conditions affected renal tissue slice function after 5 days of preservation and how adenine plus ribose affected renal function after autotransplantation in the dog. Adenosine is nearly completely degraded during 5 days of perfusion but there was little loss of adenine (10%). The adenosine triphosphate concentration in kidney cortical tissue was higher in adenine/ribose-perfused kidneys (1.41 +/- 0.19 mumol/g) than in adenosine-perfused kidneys (0.71 +/- 0.1 mumol/g) after 5 days of preservation. Tissue slices prepared from kidneys preserved in the presence of adenine plus ribose were metabolically more functional (slice volume control and electrolyte pump activity) than slices from adenosine-perfused kidneys. Adenine plus ribose had no detrimental effects on kidneys preserved for 3 days as tested in the autotransplant model but did not yield successful 5-day preservation. Because of some potentially detrimental factors in using adenosine as an adenine nucleotide synthesis precursor, we have now switched to the combination of adenine and ribose for perfusion preservation of kidneys both in the laboratory and in the clinic.

  6. Activation of biologically relevant levels of reactive oxygen species by Au/g-C3N4 hybrid nanozyme for bacteria killing and wound disinfection.

    PubMed

    Wang, Zhenzhen; Dong, Kai; Liu, Zhen; Zhang, Yan; Chen, Zhaowei; Sun, Hanjun; Ren, Jinsong; Qu, Xiaogang

    2017-01-01

    As common reactive oxygen species, H2O2 is widely used for bacterial inactivation and wound disinfection. However, the concentrations used are always higher than physiological levels, which frequently result in potential toxicity to healthy tissue and even delay wound healing. Here we report highly efficient nanozyme hybrids that are capable of activating biologically relevant concentrations of H2O2 for defending bacterial infections. The integration of AuNPs with ultrathin graphitic carbon nitride (g-C3N4) provides excellent peroxidase-activity, which can catalyze the decomposition of H2O2 to OH radicals much more efficiently, allowing the use of bio-safety levels of H2O2 for the first time. Furthermore, our system not only exhibits striking bactericidal performance against both DR Gram-negative and DR Gram-positive bacteria, but also shows high efficiency in breaking down the existing DR-biofilms and prevented formation of new biofilms in vitro. More importantly, in vivo experiments indicate that our system could significantly prevent bacterial infections and accelerate the healing rate of wounds.

  7. Biologically synthesized silver nanoparticles induce neuronal differentiation of SH-SY5Y cells via modulation of reactive oxygen species, phosphatases, and kinase signaling pathways.

    PubMed

    Dayem, Ahmed Abdal; Kim, BongWoo; Gurunathan, Sangiliyandi; Choi, Hye Yeon; Yang, Gwangmo; Saha, Subbroto Kumar; Han, Dawoon; Han, Jihae; Kim, Kyeongseok; Kim, Jin-Hoi; Cho, Ssang-Goo

    2014-07-01

    Nano-scale materials are noted for unique properties, distinct from those of their bulk material equivalents. In this study, we prepared spherical silver nanoparticles (AgNPs) with an average size of about 30 nm and tested their potency to induce neuronal differentiation of SH-SY5Y cells. Human neuroblastoma SH-SY5Y cells are considered an ideal in vitro model for studying neurogenesis, as they can be maintained in an undifferentiated state or be induced to differentiate into neuron-like phenotypes in vitro by several differentiation-inducing agents. Treatment of SH-SY5Y cells by biologically synthesized AgNPs led to cell morphological changes and significant increase in neurite length and enhanced the expression of neuronal differentiation markers such as Map-2, β-tubulin III, synaptophysin, neurogenin-1, Gap-43, and Drd-2. Furthermore, we observed an increase in generation of intracellular reactive oxygen species (ROS), activation of several kinases such as ERK and AKT, and downregulation of expression of dual-specificity phosphatases (DUSPs) in AgNPs-exposed SH-SY5Y cells. Our results suggest that AgNPs modulate the intracellular signaling pathways, leading to neuronal differentiation, and could be applied as promising nanomaterials for stem cell research and therapy.

  8. 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 ...

  9. Comparative study of 5-day cefcapene-pivoxil and 10-day amoxicillin or cefcapene-pivoxil for treatment of group A streptococcal pharyngitis in children.

    PubMed

    Sakata, Hiroshi

    2008-06-01

    In order to compare the bacteriological and clinical efficacy and safety of cefcapene-pivoxil (CFPN-PI) for 5 days, CFPN-PI for 10 days, and amoxicillin (AMPC) for 10 days for the treatment of pharyngitis due to group A beta-hemolytic streptococcus (GAS) in children, a prospective multicenter randomized open-label comparative study was performed with 12 pediatric clinics in Asahikawa between June 2006 and February 2007. Two hundred and fifty children (age range 6 months to 12 years) with signs and symptoms of acute pharyngitis were enrolled. All had a positive throat culture for GAS and were fully evaluable. Eighty-two patients received CFPN-PI 9-10 mg/kg/day three times a day for 5 days, 88 received CFPN-PI three times a day for 10 days, and 80 received AMPC three times a day for 10 days. The CFPN-PI for 5 days regimen, the CFPN-PI for 10 days regimen, and the AMPC for 10 days regimen produced bacteriological eradication at the end of treatment in 93.8%, 96.2%, and 91.7% of the patients, respectively. The clinical cure rate observed at the end of therapy was 100% of the patients in the three groups. Relapse rates were 1.3% in CFPN-PI for 5 days, 4.0% in CFPN-PI for 10 days, and 2.9% in AMPC for 10 days. There were no significant differences in eradication rate, clinical cure rate, and relapse rate between the three treatment groups. The only adverse effects were infrequent diarrhea in all three groups, and a rash which occurred in 6 patients (8.0%) of the AMPC treatment group. Five days of treatment with CFPN-PI was as efficacious in bacteriological eradication and clinical response as 10 days of CFPN-PI or AMPC treatment.

  10. Tranexamic acid mouthwash--a prospective randomized study of a 2-day regimen vs 5-day regimen to prevent postoperative bleeding in anticoagulated patients requiring dental extractions.

    PubMed

    Carter, G; Goss, A

    2003-10-01

    This prospective randomized study analyses the use of a prescribed 4.8% tranexamic acid post-operative mouthwash over 2 days vs 5 days to prevent bleeding in patients taking warfarin who require dental extractions. Eighty-five patients therapeutically anticoagulated with warfarin for various conditions, ranging in age from 21 to 86 years and requiring dental extractions, were randomly divided into two groups. Group A postoperatively received a 4.8% tranexamic acid mouthwash to be used over a 2-day period. Group B received the same mouthwash and instructions postoperatively, to be taken over 5 days. All procedures were performed on an ambulatory basis under local anaesthetic by the same surgeon. Patients were reviewed 1, 3, and 7 days postoperatively to assess bleeding. Eighty-two of the 85 patients encountered no postoperative problems. Two patients in group A and one in group B had minor postoperative bleeds that required minor ambulatory intervention to control. This study shows that a 2-day postoperative course of a 4.8% tranexamic acid mouthwash is as equally effective as a 5-day course in controlling haemostasis post-dental extractions in patient's anticoagulated with warfarin.

  11. Effect of startup circuit exercise on derivatives reactive oxygen metabolites, biological antioxidant potential levels and physical fitness of adolescents boys with intellectual disabilities

    PubMed Central

    Kim, Chang-Gyun; Lee, Jin-Seok

    2016-01-01

    The purpose of this study was to examine the effect of starup circuit exercise program on derivatives reactive oxygen metabolite (d-ROM) and biological antioxidant potential (BAP) levels and physical fitness of adolescents with intellectual disabilities, and to sugesst exercise programs to promote the health and physical development of such adolescents. Twelve students with intellectual disabilities were divided into two groups; circuit exercise group (CE group: n=6; age, 14.83±0.98 years; height, 163.83±5.78 cm; body mass, 67.08±3.32 kg; %Fat, 25.68±2.42), control group (CON group: n=6; age: 15.00±0.63 years; height, 162.33±4.41 cm; body mass, 67.50±3.62 kg; %Fat, 26.96±2.06). The CE group performed the CE program 4 times a week over a 12-week period. The CON group maintained their activities of daily living. The following were measured before and after intervention: physical fitness by before and after the completion of the training programm, and were measured and blood samples were assessed. The results of the study indicate that the 12-week CE program increased significantly physical fitness (P<0.05). Furthermore, This study proved that the CE program improved physical fitness, and reduced the d-ROM levels, and increased the BAP levels of the adolescents with intellectual disabilities. Therefore, it may enhance the health and physical development of adolescents boys with intellectual disabilities. PMID:27807529

  12. Responses of hematological parameters, beta-endorphin, cortisol, reactive oxygen metabolites, and biological antioxidant potential in horses participating in a traditional tournament.

    PubMed

    Pazzola, M; Pira, E; Sedda, G; Vacca, G M; Cocco, R; Sechi, S; Bonelli, P; Nicolussi, P

    2015-04-01

    Several concerns have been raised over the health of animals used in equestrian games that have their origins in historical or religious events and are currently held in many countries. This study investigated physiological stress response and health status of horses participating in the Sartiglia, a historical horse tournament held in the city of Oristano, Italy, which is principally based on the attempts of masked horsemen at a gallop to run a sword through a hole in a suspended silver star. Blood samples were collected from 21 horses the day before the tournament (D0), during the tournament (D1), and the day after the tournament (D2). Samples were analyzed for complete blood count and biochemical, hormonal, and oxidative stress assays. Data were analyzed using the mixed effect model with sampling session as one of the fixed effects. On the whole, blood parameters evidenced an optimal health status of horses at D0. Significant dehydration and increase of circulating glucose, enzymes, cortisol, and β-endorphin were registered at D1 (P < 0.001) with a complete recovery of physiological values just at D2. The reactive oxygen metabolites (d-ROM), from which the prooxidant activity can be evaluated, showed an increase from D0 to D1 and D2. Concentration of biological antioxidant potential, which measured the antioxidant capacity, was characterized by the maximum level registered during the tournament and counteracted the simultaneous increase of d-ROM. It can be hypothesized that the tournament played an important role in causing high levels of oxidant markers not only because of the physical exercise represented by the gallop but also because the emotional stressors. In conclusion, the tournament caused significant changes of most parameters, which rapidly recovered to baseline values within the day after. These data will certainly be useful for a future implementation of tests in equine medicine and for the improvements of knowledge of changes of blood parameters

  13. Artificial neural network modelling of biological oxygen demand in rivers at the national level with input selection based on Monte Carlo simulations.

    PubMed

    Šiljić, Aleksandra; Antanasijević, Davor; Perić-Grujić, Aleksandra; Ristić, Mirjana; Pocajt, Viktor

    2015-03-01

    Biological oxygen demand (BOD) is the most significant water quality parameter and indicates water pollution with respect to the present biodegradable organic matter content. European countries are therefore obliged to report annual BOD values to Eurostat; however, BOD data at the national level is only available for 28 of 35 listed European countries for the period prior to 2008, among which 46% of data is missing. This paper describes the development of an artificial neural network model for the forecasting of annual BOD values at the national level, using widely available sustainability and economical/industrial parameters as inputs. The initial general regression neural network (GRNN) model was trained, validated and tested utilizing 20 inputs. The number of inputs was reduced to 15 using the Monte Carlo simulation technique as the input selection method. The best results were achieved with the GRNN model utilizing 25% less inputs than the initial model and a comparison with a multiple linear regression model trained and tested using the same input variables using multiple statistical performance indicators confirmed the advantage of the GRNN model. Sensitivity analysis has shown that inputs with the greatest effect on the GRNN model were (in descending order) precipitation, rural population with access to improved water sources, treatment capacity of wastewater treatment plants (urban) and treatment of municipal waste, with the last two having an equal effect. Finally, it was concluded that the developed GRNN model can be useful as a tool to support the decision-making process on sustainable development at a regional, national and international level.

  14. Serum level of reactive oxygen metabolites (ROM) at 12 weeks of treatment with biologic agents for rheumatoid arthritis is a novel predictor for 52-week remission.

    PubMed

    Nakajima, Arata; Aoki, Yasuchika; Sonobe, Masato; Takahashi, Hiroshi; Saito, Masahiko; Nakagawa, Koichi

    2017-02-01

    We have shown that serum levels of reactive oxygen metabolites (ROM) were associated with C-reactive protein (CRP) and disease activity score based on the examination of 28 joints (DAS28) in patients with rheumatoid arthritis (RA); however, their clinical significance as biomarkers has not been elucidated. Forty-eight biologic agent (BA)-naïve RA patients were included in this study. Associations between serum levels of ROM, CRP, matrix metalloproteinase-3 (MMP-3), DAS28-erythrocyte sedimentation rate (ESR), and Health Assessment Questionnaire (HAQ) at 12 weeks of treatment and DAS28 (ESR) remission at 52 weeks (52-week remission) were investigated. The ROM serum level at baseline in the remission group (n = 34) was 527 ± 132 Carratelli units (U.Carr) (normal range <300), decreased to 335 ± 79.1 at 4 weeks, and remained low thereafter. In the non-remission group (n = 14), the ROM serum level at baseline was 592 ± 113 U.Carr, decreased to 450 ± 152 at 4 weeks, but gradually increased thereafter. Among significantly different factors at 12 weeks between the remission and non-remission groups, ROM and DAS28 (ESR) were identified as predictors of 52-week remission (p = 0.045, odds ratio 0.985, 95% confidence interval 0.97-1.000 for ROM). The cutoff value of ROM was determined to be 381.5 U.Carr (sensitivity 0.833, specificity 0.871). These results show that serum ROM levels can predict remission with high accuracy and could be a useful biomarker for achieving remission in the current treat-to-target strategy for RA.

  15. The synergistic effects of dissolved oxygen and pH on N2O production in biological domestic wastewater treatment under nitrifying conditions.

    PubMed

    Li, Pengzhang; Wang, Shuying; Peng, Yongzhen; Liu, Yue; He, Janzhong

    2015-01-01

    Nitrous oxide (N2O) is a potent greenhouse gas, which is produced during nitrifying and denitrifying processes. Some factors and mechanisms affecting N2O emission have been reported in previous literature, but wastewater biological nitrification is accompanied by a dynamic process of dissolved oxygen (DO) consumption and pH reduction, it is more meaningful to study the synergistic effects between DO and pH on N2O production. In this study, the synergistic effects between DO and pH on N2O production were investigated with real domestic wastewater. The results showed that high DO levels and a high pH could improve the oxidation ratio of NH4+-N and the production ratio of NO2--N, while effectively reducing the accumulation ratio of N2O. The NH4+-N was a prerequisite for nitrifier denitrification; when NH4+-N was oxidized completely, there would be no N2O production and an even higher concentration of NO2- The pH factor is shown to directly affect N2O emission, although free ammonia and free nitrous acid which changed with pH had no correlation with N2O emission. There were two reasons: (1) pH can influence the flow direction of electrons afforded by NH2OH oxidation; at high pH, electrons were mainly used for combining H+ and O2 (O2+4H++4e-=2H2O), the accumulation of NO2- cannot be a result of denitrification, and a higher DO can get more electrons to prefer NO2- and (2) NH4+ was the prerequisite for NH2OH oxidation, since NH2OH oxidation process was the way to provide electrons for nitrifier denitrification.

  16. Oxygen control with microfluidics.

    PubMed

    Brennan, Martin D; Rexius-Hall, Megan L; Elgass, Laura Jane; Eddington, David T

    2014-11-21

    Cellular function and behavior are affected by the partial pressure of O2, or oxygen tension, in the microenvironment. The level of oxygenation is important, as it is a balance of oxygen availability and oxygen consumption that is necessary to maintain normoxia. Changes in oxygen tension, from above physiological oxygen tension (hyperoxia) to below physiological levels (hypoxia) or even complete absence of oxygen (anoxia), trigger potent biological responses. For instance, hypoxia has been shown to support the maintenance and promote proliferation of regenerative stem and progenitor cells. Paradoxically, hypoxia also contributes to the development of pathological conditions including systemic inflammatory response, tumorigenesis, and cardiovascular disease, such as ischemic heart disease and pulmonary hypertension. Current methods to study cellular behavior in low levels of oxygen tension include hypoxia workstations and hypoxia chambers. These culture systems do not provide oxygen gradients that are found in vivo or precise control at the microscale. Microfluidic platforms have been developed to overcome the inherent limits of these current methods, including lack of spatial control, slow equilibration, and unachievable or difficult coupling to live-cell microscopy. The various applications made possible by microfluidic systems are the topic of this review. In order to understand how the microscale can be leveraged for oxygen control of cells and tissues within microfluidic systems, some background understanding of diffusion, solubility, and transport at the microscale will be presented in addition to a discussion on the methods for measuring the oxygen tension in microfluidic channels. Finally the various methods for oxygen control within microfluidic platforms will be discussed including devices that rely on diffusion from liquid or gas, utilizing on-or-off-chip mixers, leveraging cellular oxygen uptake to deplete the oxygen, relying on chemical reactions in

  17. Understanding how physical-biological coupling influences harmful algal blooms, low oxygen and fish kills in the Sea of Oman and the Western Arabian Sea.

    PubMed

    Harrison, Paul J; Piontkovski, Sergey; Al-Hashmi, Khalid

    2017-01-15

    In the last decade, green Noctiluca scintillans with its symbiont and other dinoflagellates such as Cochlodinium polykrikoides, Prorocentrum micans and Scrippsiella trochoidea have become the dominant HABs, partially replacing the previously dominant diatoms and red Noctiluca scintillans, especially during the northeast monsoon. Fish kills in the Sea of Oman are linked to a slow seasonal decline in oxygen concentration from January to November, probably due to the decomposition of a series of algal blooms and the deep, low oxygen waters periodically impinging the Omani shelf. In the western Arabian Sea, cyclonic eddies upwell low oxygen, nutrient-rich water and the subsequent algal bloom decays and lowers the oxygen further and leads to fish kills. Warming of the surface waters by 1.2°C over the last 5 decades has increased stratification and resulted in a shoaling of the oxycline. This has increased the probability and frequency of upwelling low oxygen water and subsequent fish kills.

  18. The effect of a single high dose of PGF2α administered to dairy cattle 3.5 days after ovulation on luteal function, morphology, and follicular dynamics.

    PubMed

    Cuervo-Arango, J; García-Roselló, E; García-Muñoz, A; Valldecabres-Torres, X; Martínez-Ros, P; González-Bulnes, A

    2011-12-01

    A single treatment with PGF2α is assumed to have no luteolytic effect on cows with corpora lutea < 5 days old. The objective of this study was to determine the effect of a single high dose of PGF2α administered to dairy cattle on the morphology and function of the early CL. The study followed a crossover design with a treatment cycle in which 50 mg of dinoprost were administered 3.5 days postovulation and a control untreated cycle. Ultrasound examination and blood samples were performed during the two consecutive cycles. Corpus luteum (CL) diameter, progesterone concentration, and follicular dynamics characteristics were compared between control and treated cycles. Two of nine cows (22%) developed full luteolysis. The remaining seven cows (78%) had partial luteolysis with a decrease (P < 0.05) in progesterone concentration and CL diameter for two and 12 days post-treatment, respectively. The interovulatory interval of treated cycles (19.7 ± 2.4 days) was not different (P > 0.05) from that of controls (23.8 ± 0.9 days). The transient reduction in progesterone of cows with partial luteolysis had no effect on the proportion of cows with two or three follicular waves, follicle growth rate, or preovulatory diameter (P > 0.05). Two cows developed ovarian cystic degeneration during the PGF2α-induced cycle. In conclusion, the treatment of cows with a high dose of PGF2α 3.5 days postovulation induced some degree of luteolysis in all treated cows. This resulted in partial luteolysis in 78% of treated animals and in full luteolysis in the remaining 22%.

  19. Development and validation of a 5-day-ahead hay fever forecast for patients with grass-pollen-induced allergic rhinitis.

    PubMed

    de Weger, Letty A; Beerthuizen, Thijs; Hiemstra, Pieter S; Sont, Jacob K

    2014-08-01

    One-third of the Dutch population suffers from allergic rhinitis, including hay fever. In this study, a 5-day-ahead hay fever forecast was developed and validated for grass pollen allergic patients in the Netherlands. Using multiple regression analysis, a two-step pollen and hay fever symptom prediction model was developed using actual and forecasted weather parameters, grass pollen data and patient symptom diaries. Therefore, 80 patients with a grass pollen allergy rated the severity of their hay fever symptoms during the grass pollen season in 2007 and 2008. First, a grass pollen forecast model was developed using the following predictors: (1) daily means of grass pollen counts of the previous 10 years; (2) grass pollen counts of the previous 2-week period of the current year; and (3) maximum, minimum and mean temperature (R (2)=0.76). The second modeling step concerned the forecasting of hay fever symptom severity and included the following predictors: (1) forecasted grass pollen counts; (2) day number of the year; (3) moving average of the grass pollen counts of the previous 2 week-periods; and (4) maximum and mean temperatures (R (2)=0.81). Since the daily hay fever forecast is reported in three categories (low-, medium- and high symptom risk), we assessed the agreement between the observed and the 1- to 5-day-ahead predicted risk categories by kappa, which ranged from 65 % to 77 %. These results indicate that a model based on forecasted temperature and grass pollen counts performs well in predicting symptoms of hay fever up to 5 days ahead.

  20. Development and validation of a 5-day-ahead hay fever forecast for patients with grass-pollen-induced allergic rhinitis

    NASA Astrophysics Data System (ADS)

    de Weger, Letty A.; Beerthuizen, Thijs; Hiemstra, Pieter S.; Sont, Jacob K.

    2014-08-01

    One-third of the Dutch population suffers from allergic rhinitis, including hay fever. In this study, a 5-day-ahead hay fever forecast was developed and validated for grass pollen allergic patients in the Netherlands. Using multiple regression analysis, a two-step pollen and hay fever symptom prediction model was developed using actual and forecasted weather parameters, grass pollen data and patient symptom diaries. Therefore, 80 patients with a grass pollen allergy rated the severity of their hay fever symptoms during the grass pollen season in 2007 and 2008. First, a grass pollen forecast model was developed using the following predictors: (1) daily means of grass pollen counts of the previous 10 years; (2) grass pollen counts of the previous 2-week period of the current year; and (3) maximum, minimum and mean temperature ( R 2 = 0.76). The second modeling step concerned the forecasting of hay fever symptom severity and included the following predictors: (1) forecasted grass pollen counts; (2) day number of the year; (3) moving average of the grass pollen counts of the previous 2 week-periods; and (4) maximum and mean temperatures ( R 2 = 0.81). Since the daily hay fever forecast is reported in three categories (low-, medium- and high symptom risk), we assessed the agreement between the observed and the 1- to 5-day-ahead predicted risk categories by kappa, which ranged from 65 % to 77 %. These results indicate that a model based on forecasted temperature and grass pollen counts performs well in predicting symptoms of hay fever up to 5 days ahead.

  1. Randomized, double-blind study of short-course (5 day) grepafloxacin versus 10 day clarithromycin in patients with acute bacterial exacerbations of chronic bronchitis.

    PubMed

    Langan, C E; Zuck, P; Vogel, F; McIvor, A; Peirzchala, W; Smakal, M; Staley, H; Marr, C

    1999-10-01

    The efficacy and safety of grepafloxacin were compared with clarithromycin in a randomized, double-blind, multicentre clinical trial of 805 patients with acute bacterial exacerbations of chronic bronchitis (ABECB). Patients were randomized to receive grepafloxacin 400 mg od for either 5 (n = 273) or 10 days (n = 268) or clarithromycin 250 mg bd for 10 days (n = 261). Patients were assessed pre-treatment, 3-5 days during treatment, 1-3 days post-treatment and at follow-up (21-28 days post-treatment). The clinical success rates for the evaluable patients were 91% in the 5 day grepafloxacin group, 95% in the 10 day grepafloxacin group and 86% in the clarithromycin group. At follow-up, respective rates were 72%, 81% and 73%. A total of 513 pathogens were isolated from the pre-treatment sputum specimens of 400 (49%) patients. The primary pathogens were Haemophilus influenzae (36% of isolates), Haemophilus parainfluenzae (27%), Moraxella catarrhalis (12%), Streptococcus pneumoniae (11%) and Staphylococcus aureus (3%). Pathogens were eradicated or presumed eradicated at post-treatment in 85%, 91% and 58% of evaluable patients treated with grepafloxacin for 5 days, grepafloxacin 10 days and clarithromycin 10 days, respectively. The eradication rates in both grepafloxacin groups were significantly greater than the clarithromycin group (P<0.001). All treatments were well tolerated and incidence of drug-related adverse events in each group was comparable. This study demonstrates that both a 5 and a 10 day regimen of grepafloxacin 400 mg od are as clinically and bacteriologically effective as in the treatment of ABECB clarithromycin 250 mg bd. for 10 days.

  2. [Structural and functional organization of the vestibular apparatus in rats maintained under weightless conditions for 19.5 days aboard the satellite "Cosmos-782"].

    PubMed

    Vinnikov, Ia A; Gazenko, O G; Titova, L K; Bronshteĭn, A A; Govardovskiĭ, V I

    1978-01-01

    Vestibular apparatus was investigated in rats subjected to weightlessness for 19.5 days in the satelite "Cosmos-782" and experienced acceleration on launching and landing. Some structural and functional changes were noted. They were seen in otolith clinging to the utricular receptor surface and in the peripheral arrangement of the nucleolus in the nuclei of the receptor cells. It is also possible that increased edema of the vestibular tissue resulted in destruction of some receptor cells, and within the otolith--changes in the form and structure of otoconia. In the horizontal crista the cupula was separated.

  3. Structural and Functional Organization of the Vestibular Apparatus in Rats Subjected to Weightlessness for 19.5 Days Aboard the Kosmos-782 Satellite

    NASA Technical Reports Server (NTRS)

    Vinnikov, Y. A.; Gazenko, O. G.; Titova, L. K.; Bronshteyn, A. A.; Govardovskiy, V. I.; Pevzner, R. A.; Gribakin, G. G.; Aronova, M. Z.; Kharkeyevich, T. A.; Tsirulis, T. P.

    1978-01-01

    The vestibular apparatus was investigated in rats subjected to weightlessness for 19.5 days. The vestibular apparatus was removed and its sections were fixed in a glutaraldehyde solution for investigation by light and electron microscopes. Structural and functional charges were noted in the otolith portions of the ear, with the otolith particles clinging to the utricular receptor surface and with the peripheral arrangement of the nucleolus in the nuclei of the receptor cells. It is possible that increased edema of the vestibular tissue resulted in the destruction of some receptor cells and in changes in the form and structure of the otolith. In the horizontal crista, the capula was separated.

  4. A Whole-Genome Microarray Study of Arabidopsis thaliana Semisolid Callus Cultures Exposed to Microgravity and Nonmicrogravity Related Spaceflight Conditions for 5 Days on Board of Shenzhou 8

    PubMed Central

    Neef, Maren; Ecke, Margret; Hampp, Rüdiger

    2015-01-01

    The Simbox mission was the first joint space project between Germany and China in November 2011. Eleven-day-old Arabidopsis thaliana wild type semisolid callus cultures were integrated into fully automated plant cultivation containers and exposed to spaceflight conditions within the Simbox hardware on board of the spacecraft Shenzhou 8. The related ground experiment was conducted under similar conditions. The use of an in-flight centrifuge provided a 1 g gravitational field in space. The cells were metabolically quenched after 5 days via RNAlater injection. The impact on the Arabidopsis transcriptome was investigated by means of whole-genome gene expression analysis. The results show a major impact of nonmicrogravity related spaceflight conditions. Genes that were significantly altered in transcript abundance are mainly involved in protein phosphorylation and MAPK cascade-related signaling processes, as well as in the cellular defense and stress responses. In contrast to short-term effects of microgravity (seconds, minutes), this mission identified only minor changes after 5 days of microgravity. These concerned genes coding for proteins involved in the plastid-associated translation machinery, mitochondrial electron transport, and energy production. PMID:25654111

  5. Mean winds, temperatures and the 16- and 5-day planetary waves in the mesosphere and lower thermosphere over Bear Lake Observatory (42° N 111° W)

    NASA Astrophysics Data System (ADS)

    Day, K. A.; Taylor, M. J.; Mitchell, N. J.

    2011-11-01

    Atmospheric temperatures and winds in the mesosphere and lower thermosphere have been measured simultaneously using the Aura satellite and a meteor radar at Bear Lake Observatory (42° N, 111° W). The data presented in this study is from the interval March 2008 to July 2011. The mean winds observed in the summer-time over Bear Lake Observatory show the meridional winds to be equatorward at all heights during April-August and to reach monthly-mean speeds of -12 ms-1. The mean winds are closely related to temperatures in this region of the atmosphere and in the summer the coldest mesospheric temperatures occur about two weeks after the strongest equatorward meridional winds. In other seasons the meridional winds are poleward, reaching monthly-mean values of up to 12 ms-1. The zonal winds are eastward through most of the year and in the summer strong eastward zonal wind shears of up to ~4.5 ms-1 km-1 are present. However, westward winds are observed at the upper heights in winter and sometimes during the equinoxes. Considerable inter-annual variability is observed in the mean winds and temperatures. Comparisons of the observed winds with URAP and HWM-07 reveal some significant differences. Our radar zonal wind observations are generally more weakly eastward than these predicted by the URAP model zonal winds. Considering the radar meridional winds, in comparison to the HWM-07 our observations reveal equatorward flow at all heights in the summer whereas HWM-07 suggests that only weakly equatorward, or even poleward, flows occur at the lower heights. However, the zonal winds observed by the radar and modelled by HWM-07 are generally similar in structure and strength. Signatures of the 16- and 5-day planetary waves are clearly evident in both the radar-wind data and Aura-temperature. Short-lived wave events can reach large amplitudes of up to ~15 ms-1 and 8 K and 20 ms-1 and 10 K for the 16- and 5-day wave, respectively. A clear seasonal and short-term variability are

  6. A phase I study of 1,2-diamminomethyl-cyclobutane-platinum (II)-lactate (D-19466; lobaplatin) administered daily for 5 days.

    PubMed Central

    Gietema, J. A.; de Vries, E. G.; Sleijfer, D. T.; Willemse, P. H.; Guchelaar, H. J.; Uges, D. R.; Aulenbacher, P.; Voegeli, R.; Mulder, N. H.

    1993-01-01

    A phase I trial was conducted with lobaplatin (D-19466; 1,2-diamminomethyl-cyclobutane-platinum (II)-lactate) i.v. bolus daily for 5 days every 4 weeks. After entering five patients toxicity appeared to be related to renal function, therefore the individual dose (total dose 20-100 mg m-2 over 5 days) of lobaplatin was modified according to creatinine clearance (CRCL) and escalated in patients. Twenty-seven patients with refractory solid tumours received 72 courses. Thrombocytopenia was dose-limiting, its degree was related to dose and CRCL at time of drug administration. With a CRCL of 60-80 ml min-1 the maximum tolerated dose was 40 mg m-2, with a CRCL of 81-100 ml min-1 70 mg m-2, and with a CRCL > 100 ml min-1 it was 85 mg m-2. Platelet and leukocyte nadirs were observed around day 21. The percentual platelet nadir (percentage of day 1 platelet count) correlated with CRCL at different dose levels and could be described by 0.76 x CRCL (ml min-1) - (1.45 x dose (mg m-2) + 43.38. This equation tested in 20 patients (28 courses) produced a correlation between observed and predicted percentual platelet nadir (r = 0.82, P < 0.001). No renal function impairment occurred. Urinary excretion of platinum (by A.A.S) was estimated in six patients and revealed that 91.5% (s.e. +/- 7.9) of the platinum dose was excreted within 4 h. Responses (one PR, one CR) occurred in two patients with ovarian cancer (both pretreated with carboplatin and cisplatin). The recommended dose of lobaplatin i.v. bolus daily for 5 days for phase II studies depends on renal function, namely 30 mg m-2 at CRCL 60-80 ml min-1; 55 mg m-2 at CRCL 81-100 ml min-1; 70 mg m-2 at CRCL > 100 ml min-1. PMID:8431374

  7. A revisit to O2 sensing and transduction in the carotid body chemoreceptors in the context of reactive oxygen species biology.

    PubMed

    Gonzalez, C; Agapito, M T; Rocher, A; Gomez-Niño, A; Rigual, R; Castañeda, J; Conde, S V; Obeso, A

    2010-12-31

    Oxygen-sensing and transduction in purposeful responses in cells and organisms is of great physiological and medical interest. All animals, including humans, encounter in their lifespan many situations in which oxygen availability might be insufficient, whether acutely or chronically, physiologically or pathologically. Therefore to trace at the molecular level the sequence of events or steps connecting the oxygen deficit with the cell responses is of interest in itself as an achievement of science. In addition, it is also of great medical interest as such knowledge might facilitate the therapeutical approach to patients and to design strategies to minimize hypoxic damage. In our article we define the concepts of sensors and transducers, the steps of the hypoxic transduction cascade in the carotid body chemoreceptor cells and also discuss current models of oxygen- sensing (bioenergetic, biosynthetic and conformational) with their supportive and unsupportive data from updated literature. We envision oxygen-sensing in carotid body chemoreceptor cells as a process initiated at the level of plasma membrane and performed by a hemoprotein, which might be NOX4 or a hemoprotein not yet chemically identified. Upon oxygen-desaturation, the sensor would experience conformational changes allosterically transmitted to oxygen regulated K+ channels, the initial effectors in the transduction cascade. A decrease in their opening probability would produce cell depolarization, activation of voltage dependent calcium channels and release of neurotransmitters. Neurotransmitters would activate the nerve endings of the carotid body sensory nerve to convey the information of the hypoxic situation to the central nervous system that would command ventilation to fight hypoxia.

  8. A study of gravity-wave spectra in the troposphere and stratosphere at 5-min to 5-day periods with the Poker Flat MST radar

    NASA Technical Reports Server (NTRS)

    Bemra, R. S.; Rastogi, P. K.; Balsley, B. B.

    1986-01-01

    An analysis of frequency spectra at periods of about 5 days to 5 min from two 20-day sets of velocity measurements in the stratosphere and troposphere region obtained with the Poker Flat mesosphere-stratosphere-troposphere (MST) radar during January and June, 1984 is presented. A technique based on median filtering and averaged order statistics for automatic editing, smoothing and spectral analysis of velocity time series contaminated with spurious data points or outliers is outlined. The validity of this technique and its effects on the inferred spectral index was tested through simulation. Spectra obtained with this technique are discussed. The measured spectral indices show variability with season and height, especially across the tropopause. The discussion briefly outlines the need for obtaining better climatologies of velocity spectra and for the refinements of the existing theories to explain their behavior.

  9. The 27-day versus 13.5-day variations in the solar Lyman-alpha radiation and the radio wave absorption in the lower ionosphere over Europe

    NASA Technical Reports Server (NTRS)

    Delamorena, B. A.; Lastovicka, Jan; Rapoport, Z. TS.; Alberca, L.

    1989-01-01

    In order to clarify the question of solar periods in absorption, the pattern was studied of the solar Lyman-alpha radiation (the principal ionizing agent of the lower ionosphere) and of the radio wave absorption at five widely spaced places in Europe. When the solar Lyman-alpha flux variability is very well developed, then it dominates in the lower ionospheric variability. The most pronounced Lyman-alpha variation on time scale day-month is the solar rotation variation (about 27 days). When the Lyman-alpha variability is developed rather poorly, as it is typical for periods dominated by the 13.5 day variability, then the lower ionospheric variability appears to be dominated by variations of meteorological origin. The conclusions hold for all five widely spaced placed in Europe.

  10. Hepatic transcriptomic alterations for N,N-dimethyl-p-toluidine (DMPT) and p-toluidine after 5-day exposure in rats.

    PubMed

    Dunnick, June K; Shockley, Keith R; Morgan, Daniel L; Brix, Amy; Travlos, Gregory S; Gerrish, Kevin; Michael Sanders, J; Ton, T V; Pandiri, Arun R

    2017-04-01

    N,N-dimethyl-p-toluidine (DMPT), an accelerant for methyl methacrylate monomers in medical devices, was a liver carcinogen in male and female F344/N rats and B6C3F1 mice in a 2-year oral exposure study. p-Toluidine, a structurally related chemical, was a liver carcinogen in mice but not in rats in an 18-month feed exposure study. In this current study, liver transcriptomic data were used to characterize mechanisms in DMPT and p-toluidine liver toxicity and for conducting benchmark dose (BMD) analysis. Male F344/N rats were exposed orally to DMPT or p-toluidine (0, 1, 6, 20, 60 or 120 mg/kg/day) for 5 days. The liver was examined for lesions and transcriptomic alterations. Both chemicals caused mild hepatic toxicity at 60 and 120 mg/kg and dose-related transcriptomic alterations in the liver. There were 511 liver transcripts differentially expressed for DMPT and 354 for p-toluidine at 120 mg/kg/day (false discovery rate threshold of 5 %). The liver transcriptomic alterations were characteristic of an anti-oxidative damage response (activation of the Nrf2 pathway) and hepatic toxicity. The top cellular processes in gene ontology (GO) categories altered in livers exposed to DMPT or p-toluidine were used for BMD calculations. The lower confidence bound benchmark doses for these chemicals were 2 mg/kg/day for DMPT and 7 mg/kg/day for p-toluidine. These studies show the promise of using 5-day target organ transcriptomic data to identify chemical-induced molecular changes that can serve as markers for preliminary toxicity risk assessment.

  11. Prenatal exposure to ethanol during late gestation facilitates operant self-administration of the drug in 5-day-old rats

    PubMed Central

    Miranda-Morales, Roberto Sebastián; Nizhnikov, Michael E.; Spear, Norman E.

    2014-01-01

    Prenatal ethanol exposure modifies postnatal affinity to the drug, increasing the probability of ethanol use and abuse. The present study tested developing rats (5-day-old) in a novel operant technique to assess the degree of ethanol self-administration as a result of prenatal exposure to low ethanol doses during late gestation. On a single occasion during each of gestational days 17–20, pregnant rats were intragastrically administered ethanol 1 g/kg, or water (vehicle). On postnatal day 5, pups were tested on a novel operant conditioning procedure in which they learned to touch a sensor to obtain 0.1% saccharin, 3% ethanol, or 5% ethanol. Immediately after a 15-min training session, a 6-min extinction session was given in which operant behavior had no consequence. Pups were positioned on a smooth surface and had access to a touch-sensitive sensor. Physical contact with the sensor activated an infusion pump, which served to deliver an intraoral solution as reinforcement (Paired group). A Yoked control animal evaluated at the same time received the reinforcer when its corresponding Paired pup touched the sensor. Operant behavior to gain access to 3% ethanol was facilitated by prenatal exposure to ethanol during late gestation. In contrast, operant learning reflecting ethanol reinforcement did not occur in control animals prenatally exposed to water only. Similarly, saccharin reinforcement was not affected by prenatal ethanol exposure. These results suggest that in 5-day-old rats, prenatal exposure to a low ethanol dose facilitates operant learning reinforced by intraoral administration of a low-concentration ethanol solution. This emphasizes the importance of intrauterine experiences with ethanol in later susceptibility to drug reinforcement. The present operant conditioning technique represents an alternative tool to assess self-administration and seeking behavior during early stages of development. PMID:24355072

  12. Biology Notes

    ERIC Educational Resources Information Center

    School Science Review, 1976

    1976-01-01

    Describes nine biology experiments, including osmosis, genetics; oxygen content of blood, enzymes in bean seedlings, preparation of bird skins, vascularization in bean seedlings, a game called "sequences" (applied to review situations), crossword puzzle for human respiration, and physiology of the woodlouse. (CS)

  13. Using oxygen at home

    MedlinePlus

    Oxygen - home use; COPD - home oxygen; Chronic obstructive airways disease - home oxygen; Chronic obstructive lung disease - home oxygen; Chronic bronchitis - home oxygen; Emphysema - home oxygen; Chronic respiratory ...

  14. 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.

  15. Oxygen Therapy

    MedlinePlus

    ... stored as a gas or liquid in special tanks. These tanks can be delivered to your home and contain ... they won’t run out of oxygen. Portable tanks and oxygen concentrators may make it easier for ...

  16. Stable Isotope Analyses of Phosphate Oxygen From Micro-samples of Biological Apatite: A new Routine Procedure for Silverphosphate Micro-precipitation and the Removal of Organic Contamination

    NASA Astrophysics Data System (ADS)

    Wiedemann-Bidlack, F. B.; Colman, A. S.; Fogel, M. L.

    2003-12-01

    Oxygen isotope analyses in bone and teeth of living and fossil animals are widely used for testing hypotheses about variability of diet and habitat. For the analysis of environmental or dietary changes in the past, tooth enamel has become the preferred study material, because its mineral content is higher than bone and dentine, and the relatively large size of the carbonato-apatite crystals of enamel make it more stable against post mortem diagenetic alteration than dentine or bone. Intra-tooth sampling of dental enamel is increasingly used for the investigation of seasonal climate variability, taking advantage of both the high correlation between an animal's drinking water and the δ 18O in its mineralized tissues and the incremental growth pattern of tooth enamel. The different oxygen-containing ions of bioapatite (phosphate, carbonate, and hydroxyl group) incorporate into the mineral lattice at different rates during enamel mineralization, and differ in their susceptibility against post mortem diagenetic alteration. In addition, it is difficult to account for the different reaction chemistries of phosphate, carbonate, and hydroxyl group using isotope analysis techniques that include all oxygen contained in the enamel (e.g., laser ablation). These problems can be addressed analyzing phosphate oxygen only. However, two major factors limit the potential of δ 18O analyses in dental enamel: A) the starting sample size for isotope analyzes often precludes the use of small teeth or the intra-tooth sampling of a given tooth; B) Small amounts of biogenic organic material in tooth enamel (less than 1% by wt) can reduce the precision and lead to anomalous analytical results in δ 18O measurements on Ag3PO4 produced from tooth enamel. A new procedure was developed for the pre-treatment and δ 18O analysis of phosphate from small samples (500 μ g) of tooth enamel containing organic matter. Ag3PO{4} was precipitated quantitatively for analysis of δ 18Ophosphate using a

  17. Oxygenated Derivatives of Hydrocarbons

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For the book entitled “Insect Hydrocarbons: Biology, Biochemistry and Chemical Ecology”, this chapter presents a comprehensive review of the occurrence, structure and function of oxygenated derivatives of hydrocarbons. The book chapter focuses on the occurrence, structural identification and functi...

  18. Emergence of multipotent hemopoietic cells in the yolk sac and paraaortic splanchnopleura in mouse embryos, beginning at 8.5 days postcoitus.

    PubMed Central

    Godin, I; Dieterlen-Lièvre, F; Cumano, A

    1995-01-01

    We show by an in vitro approach that multipotent hemopoietic cells can be detected in the body of the mouse embryo between the stages of 10-25 somites (8.5-9.5 days of gestation)--i.e., prior to liver colonization (28-32 pairs of somites). Interestingly, hemopoietic cells appear in parallel in this location, the paraaortic splanchnopleura, and in the yolk sac, where they represent a new generation by reference to the primitive hemopoietic stem cells. Lymphoid cell clones, which could differentiate into mature B cells, were obtained from yolk sac and paraaortic splanchnopleura cell preparations but not from other tissues of the embryonic body. These B-cell precursors were first detected around the stage of 10 somites; thereafter, their initial minute numbers increased in parallel in the yolk sac and the paraaortic splanchnopleura, suggesting that their emergence in the two sites was simultaneous. By single cell manipulation, we show that these precursors can generate B and T lymphocytes and myeloid cells; these precursors can thus be defined as multipotent hemopoietic cells. Images Fig. 1 Fig. 4 PMID:7846049

  19. Synthesis and structural characterization of silver(I), aluminium(III) and cobalt(II) complexes with 4-isopropyltropolone (hinokitiol) showing noteworthy biological activities. Action of silver(I)-oxygen bonding complexes on the antimicrobial activities.

    PubMed

    Nomiya, Kenji; Yoshizawa, Akira; Tsukagoshi, Ken; Kasuga, Noriko Chikaraishi; Hirakawa, Shoko; Watanabe, Jun

    2004-01-01

    Through two unequivalent oxygen donor atoms of the hinokitiol (Hhino; C10H12O2; 4-isopropyltropolone) ligand that showed noteworthy biological activities, the dimeric, silver(I)-oxygen bonding complex [Ag(hino)]2 1, the monomeric aluminium(III) complex [Al(hino)3].0.5H2O 4 and the cobalt(II) complex "[Co(hino)2]2.H2O" 6 were synthesized and characterized with elemental analysis, thermogravimetric and differential thermal analysis (TG/DTA), FTIR and solution (1H and 13C) NMR spectroscopy. The crystal structure of 1 was determined by Rietveld analysis based on X-ray powder diffraction (XPD) data and those of [Al(hino)3].MeOH 4a and [Co(hino)2(EtOH)]2 6a, being obtained as yellow block crystals and red platelet crystals, respectively, by crystallization of 4 and 6, were determined by single-crystal X-ray analysis. The antimicrobial activities of 1, 4 and 6, evaluated with minimum inhibitory concentration (MIC; microg ml(-1)), were compared with those of other metal complexes (M=Na, Li, Cs, Ca, V, Zn) with the hino- ligand. The antimicrobial activities observed in the alkali-metal salts strongly suggested that they were attributed to the effect of the anionic hino- species. The antimicrobial activities of 1 were significantly enhanced, whereas those of other metal complexes were suppressed, compared with those of the neutral Hhino and anionic hino- molecules. The antimicrobial activities observed in 1 were comparable with those of other recently found silver(I)-oxygen bonding complexes, the ligands of which had no activity. Thus, it is proposed that the antimicrobial activities of the silver(I)-oxygen bonding complexes are due to a direct interaction or complexation of the silver(I) ion with biological ligands such as protein, enzyme and membrane, and the coordinating ligands of the silver(I) complexes play the role of a carrier of the silver(I) ion to the biological system.

  20. [Apneic oxygenation].

    PubMed

    Alekseev, A V; Vyzhigina, M A; Parshin, V D; Fedorov, D S

    2013-01-01

    Recent technological advances in thoracic and tracheal surgery make the anaesthesiologist use different respiratory techniques during the operation. Apneic oxygenation is a one of alternative techniques. This method is relatively easy in use, does not require special expensive equipment and is the only possible technique in several clinical situations when other respiratory methods are undesirable or cannot be used. However there is no enough information about apneic oxygenation in Russian. This article reviews publications about apneic oxygenation. The review deals with experiments on diffusion respiration in animals, physiological changes during apneic oxygenation in man and defines clinical cases when apneic oxygenation can be used.

  1. 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.

  2. Fertility of Holstein heifers after two doses of PGF2α in 5-day CO-Synch progesterone-based synchronization protocol.

    PubMed

    Say, Erkan; Çoban, Serdal; Nak, Yavuz; Nak, Deniz; Kara, Uğur; White, Stephanie; Kasimanickam, Vanmathy; Kasimanickam, Ramanathan

    2016-09-01

    The objective of the study was to determine the effect of three different PGF2α (PGF) treatments in the 5-day CO-Synch progesterone-based synchronization protocol on artificial insemination (AI) pregnancy rate (PR) in Holstein heifers in Turkey and the United States. We hypothesized that two doses of PGF administered concurrently or 6 hours apart would result in greater AI pregnancy compared with a single dose of PGF on Day 5 at controlled internal drug release (CIDR) removal. In Turkey, Holstein heifers (n = 450) from one farm in the province of Adana and another farm in the province of Bursa were included. In the US, Holstein heifers (n = 483) from two locations in the state of Idaho were included. Heifers within locations were randomly allocated to one of three protocol groups: 1PGF-received 25 mg IM of dinoprost at CIDR removal; 2Co-PGF-received 50 mg IM of dinoprost at CIDR removal, and 2PGF-received 25 mg IM of dinoprost at CIDR removal and an additional 25 mg IM of dinoprost 6 hours later. All heifers received a CIDR (1.38 g of progesterone) and GnRH (10 μg IM of Buserelin [Turkey] or gonadorelin hydrochloride [US]) on Day 0. The CIDRs were removed on Day 5, and each heifer was given PGF according to the assigned treatments. On Day 7, each heifer was given another dose of GnRH and concurrently inseminated at 56 hours after CIDR removal. Heifers in both experiments were examined for pregnancy status between 35 and 45 days after AI. Overall, controlling for age, the heifers in the 2PGF group had greater AI-PR (61.7% [192/311]) than heifers in 2Co-PGF (48.2% [149/309]; P < 0.001) or 1PGF (53.7% [168/313]; P < 0.05) groups. No difference was observed between 2Co-PGF and 1PGF groups (P > 0.1). In Turkey, the heifers in the 2PGF group had a greater AI-PR (60% [90/150]) than 2Co-PGF (45.3% (68/150); P < 0.01] group. No difference was observed between 2PGF and 1PGF (55.3% [83/150]) groups (P > 0.1). There was a trend for AI pregnancy between 1

  3. Comparison of follicular dynamics and hormone concentrations between the 7-day and 5-day CO-Synch + CIDR program in primiparous beef cows.

    PubMed

    Bridges, G A; Mussard, M L; Helser, L A; Day, M L

    2014-03-01

    The objectives were to compare follicular dynamics, preovulatory estradiol concentrations, and progesterone concentrations between the 7-day (7CO, n = 15) and 5-day (5CO, n = 13) CO-Synch + controlled internal drug release device (CIDR) program in primiparous suckled beef cows. On Day -7 (7CO) or Day -5 (5CO), GnRH (100 μg) was administered (GnRH-1) and a CIDR was inserted. On Day 0, hour 0, CIDR was removed and cows received PGF2α (25 mg) at hours 0 and 12. Animals were administered GnRH (100 μg, GnRH-2) at either hour 60 (7CO) or 72 (5CO). Follicular growth and ovulation to both GnRH-1 and GnRH-2 were evaluated using ultrasonography. Concentrations of estradiol were determined in blood samples taken at hours 0, 36, 60, and 72 (5CO). Blood samples were collected on Days 5, 8, and 14 for progesterone quantification. Ovulation rate to GnRH-1 did not differ between the 7CO (11/15) and 5CO (8/13) treatments, and for all dependent variables the statistical model included treatment, ovulation to GnRH-1, and their interaction. Diameter (mm) of the ovulatory follicle did not differ between treatments (13.4 ± 0.3) but was greater (P < 0.05) in cows that responded to GnRH-1 (13.8 ± 0.3) than those did not (12.6 ± 0.6). Maximum estradiol concentrations tended (P = 0.06) to be greater in the 5CO (7.3 ± 0.5 pg/mL) than 7CO (6.1 ± 0.7 pg/mL) treatment and tended to be greater (P = 0.08) in cows that responded to GnRH-1 (7.1 ± 0.5 pg/mL) than those did not (5.6 ± 0.9 pg/mL). Three cows in the 7CO treatment failed to develop a CL after GnRH-2. There was a treatment by response to GnRH-1 interaction (P < 0.05) for progesterone concentrations. In cows that did not respond to GnRH-1 in the 7CO treatment, progesterone concentrations were less (P < 0.05) than in those that responded to GnRH-1 in the 7CO treatment and tended (P = 0.09) to be less than in cows in the 5CO treatment that did not respond to GnRH-1. In conclusion, these findings demonstrate that failure to

  4. Decontamination efficacy of erbium:yttrium-aluminium-garnet and diode laser light on oral Candida albicans isolates of a 5-day in vitro biofilm model.

    PubMed

    Sennhenn-Kirchner, Sabine; Schwarz, Peter; Schliephake, Henning; Konietschke, Frank; Brunner, Edgar; Borg-von Zepelin, Margarete

    2009-05-01

    The different forms of superficial and systemic candidiasis are often associated with biofilm formation on surfaces of host tissues or medical devices. The biofilm formation of Candida spp., in general, necessitates significantly increased amounts of antifungal agents for therapy. Often the therapeutic effect is doubtful. A 5-day biofilm model with oral Candida isolates was established according to Chandra et al. (J Dent Res 80:903-908, 2001) on glass and titanium surfaces and was modified by Sennhenn-Kirchner et al. (Z Zahnärztl Implantol 3:45-51, 2007) to investigate different aspects unanswered in the field of dentistry. In this model, the efficacy of erbium:yttrium-aluminium-garnet (Er:YAG) light (2940 nm, 100 mJ, 10 Hz, 300 micros pulsed mode applied for 80 s) and diode laser light (810 nm, 1 W, continuous wave mode applied for 20 s with four repetitions after 30 s pauses each) was evaluated and compared to untreated controls. The photometric evaluation of the samples was completed by observations on morphological changes of yeast cells grown in the biofilm. Compared to the untreated controls Candida cells grown in mature in vitro biofilms were significantly reduced by both wavelengths investigated. Comparison between the different methods of laser treatment additionally revealed a significantly greater effect of the Er:YAG over the diode laser. Scanning electron microscopy findings proved that the diode laser light was effective in direct contact mode. In contrast, in the areas without direct contact, the fungal cells were left almost unchanged. The Er:YAG laser damaged the fungal cells to a great extent wherever it was applied.

  5. One session of high-intensity interval training (HIIT) every 5 days, improves muscle power but not static balance in lifelong sedentary ageing men

    PubMed Central

    Sculthorpe, Nicholas F.; Herbert, Peter; Grace, Fergal

    2017-01-01

    Abstract Background: Declining muscle power during advancing age predicts falls and loss of independence. High-intensity interval training (HIIT) may improve muscle power, but remains largely unstudied in ageing participants. Methods: This randomized controlled trial (RCT) investigated the efficacy of a low-frequency HIIT (LfHIIT) intervention on peak muscle power (peak power output [PPO]), body composition, and balance in lifelong sedentary but otherwise healthy males. Methods: Thirty-three lifelong sedentary ageing men were randomly assigned to either intervention (INT; n = 22, age 62.3 ± 4.1 years) or control (n = 11, age 61.6 ± 5.0 years) who were both assessed at 3 distinct measurement points (phase A), after 6 weeks of conditioning exercise (phase B), and after 6 weeks of HIIT once every 5 days in INT (phase C), where control remained inactive throughout the study. Results: Static balance remained unaffected, and both absolute and relative PPO were not different between groups at phases A or B, but increased significantly in INT after LfHIIT (P < 0.01). Lean body mass displayed a significant interaction (P < 0.01) due to an increase in INT between phases B and C (P < 0.05). Conclusions: 6 weeks of LfHIIT exercise feasible and effective method to induce clinically relevant improvements in absolute and relative PPO, but does not improve static balance in sedentary ageing men. PMID:28178145

  6. Evaluation of Biomarkers of Exposure in Smokers Switching to a Carbon-Heated Tobacco Product: A Controlled, Randomized, Open-Label 5-Day Exposure Study

    PubMed Central

    Haziza, Christelle; Weitkunat, Rolf; Magnette, John

    2016-01-01

    Introduction: Tobacco harm reduction aims to provide reduced risk alternatives to adult smokers who would otherwise continue smoking combustible cigarettes (CCs). This randomized, open-label, three-arm, parallel-group, single-center, short-term confinement study aimed to investigate the effects of exposure to selected harmful and potentially harmful constituents (HPHCs) of cigarette smoke in adult smokers who switched to a carbon-heated tobacco product (CHTP) compared with adult smokers who continued to smoke CCs and those who abstained from smoking for 5 days. Methods: Biomarkers of exposure to HPHCs, including nicotine and urinary excretion of mutagenic material, were measured in 24-hour urine and blood samples in 112 male and female Caucasian smokers switching from CCs to the CHTP ad libitum use. Puffing topography was assessed during product use. Results: Switching to the CHTP or smoking abstinence (SA) resulted in marked decreases from baseline to Day 5 in all biomarkers of exposure measured, including carboxyhemoglobin (43% and 55% decrease in the CHTP and SA groups, respectively). The urinary excretion of mutagenic material was also markedly decreased on Day 5 compared with baseline (89% and 87% decrease in the CHTP and SA groups, respectively). No changes in biomarkers of exposure to HPHCs or urinary mutagenic material were observed between baseline and Day 5 in the CC group. Conclusions: Our results provide clear evidence supporting a reduction in the level of exposure to HPHCs of tobacco smoke in smokers who switch to CHTP under controlled conditions, similar to that observed in SA. Implications: The reductions observed in biomarkers of exposure to HPHCs of tobacco smoke in this short-term study could potentially also reduce the incidence of cancer, cardiovascular and respiratory diseases in those smokers who switch to a heated tobacco product. PMID:26817490

  7. Oxygen Mass Transfer Coefficient (k sub L a’) Consideration for Scale-Up Fermentation Systems at the Biotechnology Laboratory U.S. Army Edgewood Chemical Biological Center

    DTIC Science & Technology

    2011-02-01

    SECURITY CLASSIFICATION OF: a. REPORT u b. ABSTRACT u c . THIS PAGE U 17. LIMITATION OF ABSTRACT UL 18. NUMBER OF PAGES 27 19a. NAME OF...Service. Acknowledgment The authors would like to acknowledge Dennis C . Lukens (U.S. Army Edgewood Chemical Biological Center) for his technical...Scientific, Edison, NJ). These fermentation systems are used for research and development in bioprocess optimization (e.g., Micros 30 L system) as well as

  8. EFFECT OF HYPOXIA ON THE RATE OF OXYGEN CONSUMPTION OF NEWBORN, YOUNG, AND ADULT MICE AT VARIOUS ENVIRONMENTAL TEMPERATURES,

    DTIC Science & Technology

    Critical Po2 that is, Po2 below the point at which oxygen consumption is reduced - was measured in newborn, 5-day-old, and adult mice. At...thermoneutral environmental temperatures, the critical Po2 of newborn was 85 mm. Hg; that of 5-day-old mice was 100 mm. Hg; and that of adults was 70 mm. Hg

  9. Metabolic Response of Visceral White Adipose Tissue of Obese Mice Exposed for 5 Days to Human Room Temperature Compared to Mouse Thermoneutrality

    PubMed Central

    van der Stelt, Inge; Hoevenaars, Femke; Široká, Jitka; de Ronde, Lidwien; Friedecký, David; Keijer, Jaap; van Schothorst, Evert

    2017-01-01

    Housing of laboratory mice at room temperature (22°C) might be considered a constant cold stress, which induces a thermogenic program in brown adipose tissue (BAT). However, the early adaptive response of white adipose tissue (WAT), the fat storage organ of the body, to a change from thermoneutrality to room temperature is not known. This was investigated here for various WAT depots, focusing on epididymal WAT (eWAT), widely used as reference depot. Male adult diet-induced obese (DIO) C57BL/6JOlaHsd mice housed at thermoneutrality (29°C), were for 5 days either switched to room temperature (22°C) or remained at thermoneutrality. Energy metabolism was continuously measured using indirect calorimetry. At the end of the study, serum metabolomics and WAT transcriptomics were performed. We confirmed activation of the thermogenic program in 22°C housed mice. Body weight and total fat mass were reduced. Whole body energy expenditure (EE) was increased, with a higher fatty acid to carbohydrate oxidation ratio and increased serum acylcarnitine levels, while energy intake was not significantly different between the two groups. Transcriptome analysis of eWAT identified tissue remodeling and inflammation as the most affected processes. Expression of pro-inflammatory M1 macrophage-related genes, and M1 over M2 macrophage ratio were decreased, which might be linked to an increased insulin sensitivity. Markers of thermogenesis were not altered in eWAT. Decreased expression of tryptophan hydroxylase 2 (Tph2) and cholecystokinin (Cck) might represent altered neuroendocrine signaling. eWAT itself does not show increased fatty acid oxidation. The three measured WATs, epididymal, mesenteric, and retroperitoneal, showed mainly similar responses; reduced inflammation (s100a8), decreased carbohydrate oxidation, and no or small differences in fatty acid oxidation. However, Ucp1 was only expressed and increased in rWAT in 22°C housed mice. Cck expression was decreased in the three

  10. Reduction of N2O and NO generation in anaerobic-aerobic (low dissolved oxygen) biological wastewater treatment process by using sludge alkaline fermentation liquid.

    PubMed

    Zhu, Xiaoyu; Chen, Yinguang

    2011-03-15

    This paper reported an efficient method to significantly reduce nitrous oxide (N(2)O) and nitric oxide (NO) generation in anaerobic-aerobic (low dissolved oxygen) processes. It was found that by the use of waste-activated sludge alkaline fermentation liquid as the synthetic wastewater-carbon source, compared with the commonly used carbon source in the literature (e.g., acetic acid), the generation of N(2)O and NO was reduced by 68.7% and 50.0%, respectively, but the removal efficiencies of total phosphorus (TP) and total nitrogen (TN) were improved. Both N(2)O and NO were produced in the low dissolved oxygen (DO) stage, and the use of sludge fermentation liquid greatly reduced their generation from the denitrification. The presences of Cu(2+) and propionic acid in fermentation liquid were observed to play an important role in the reduction of N(2)O and NO generation. The analysis of the activities of denitrifying enzymes suggested that sludge fermentation liquid caused the significant decrease of both nitrite reductase activity to NO reductase activity ratio and NO reductase activity to N(2)O reductase activity ratio, which resulted in the lower generation of NO and N(2)O. Fluorescence in situ hybridization analysis indicated that the number of glycogen accumulating bacteria, which was reported to be relevant to nitrous oxide generation, in sludge fermentation liquid reactor was much lower than that in acetic acid reactor. The quantitative detection of the nosZ gene, encoding nitrous oxide reductase, showed that the use of fermentation liquid increased the number of bacteria capable of reducing N(2)O to N(2). The feasibility of using sludge fermentation liquid to reduce NO and N(2)O generation in an anaerobic-low DO process was finally confirmed for a municipal wastewater.

  11. 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…

  12. Effects of indirect actions and oxygen on relative biological effectiveness: estimate of DSB induction and conversion induced by gamma rays and helium ions.

    PubMed

    Tsai, Ju-Ying; Chen, Fang-Hsin; Hsieh, Tsung-Yu; Hsiao, Ya-Yun

    2015-07-01

    Clustered DNA damage other than double-strand breaks (DSBs) can be detrimental to cells and can lead to mutagenesis or cell death. In addition to DSBs induced by ionizing radiation, misrepair of non-DSB clustered damage contributes extra DSBs converted from DNA misrepair via pathways for base excision repair and nucleotide excision repair. This study aimed to quantify the relative biological effectiveness (RBE) when DSB induction and conversion from non-DSB clustered damage misrepair were used as biological endpoints. The results showed that both linear energy transfer (LET) and indirect action had a strong impact on the yields for DSB induction and conversion. RBE values for DSB induction and maximum DSB conversion of helium ions (LET = 120 keV/μm) to (60)Co gamma rays were 3.0 and 3.2, respectively. These RBE values increased to 5.8 and 5.6 in the absence of interference of indirect action initiated by addition of 2-M dimethylsulfoxide. DSB conversion was ∼1-4% of the total non-DSB damage due to gamma rays, which was lower than the 10% estimate by experimental measurement. Five to twenty percent of total non-DSB damage due to helium ions was converted into DSBs. Hence, it may be possible to increase the yields of DSBs in cancerous cells through DNA repair pathways, ultimately enhancing cell killing.

  13. Exploring the kinetic and thermodynamic aspects of four-electron electrochemical reactions: electrocatalysis of oxygen evolution by metal oxides and biological systems.

    PubMed

    Wang, Vincent C-C

    2016-08-10

    Finding fundamental and general mechanisms for electrochemical reactions, such as the oxygen evolution reaction (OER) from water and reduction of CO2, plays vital roles in developing the desired electrocatalysts for facilitating solar fuel production. Recently, density functional theory (DFT) calculations have shown that there is a universal scaling relation of adsorption energy between key intermediate species, HO(ad) and HOO(ad), on the surface of metal oxides as OER electrocatalysts. In this paper, a kinetic and thermodynamic model for the four-electron electrochemical reaction based on previous OER mechanisms proposed by DFT calculations is developed to further investigate the electrocatalytic properties over a wide range of metal oxides and photosystem II. The OER activity of metal oxides (i.e. electrocatalytic current) calculated from the DFT-calculated equilibrium potentials with kinetic properties, such as the rate constants for interfacial electron transfer and catalytic turnover, can lead to a volcano-shaped trend that agrees with the results observed in experiments. In addition, the kinetic aspects of the impact on the electrocatalysts are evaluated. Finally, comparing the results of metal oxides and photosystem II, and fitting experimental voltammograms give further insights into kinetic and thermodynamic roles. Here, the general guidelines for designing OER electrocatalysts with unified kinetic and thermodynamic properties are presented.

  14. MICREDOX--development of a ferricyanide-mediated rapid biochemical oxygen demand method using an immobilised Proteus vulgaris biocomponent.

    PubMed

    Pasco, Neil; Baronian, Keith; Jeffries, Cy; Webber, Judith; Hay, Joanne

    2004-10-15

    Biochemical oxygen demand (BOD) is an international regulatory environmental index for monitoring organic pollutants in wastewater and the current legislated standard test for BOD monitoring requires 5 days to complete (BOD5 test). We are developing a rapid microbial technique, MICREDOX, for measuring BOD by eliminating oxygen and, instead, quantifying an equivalent biochemical co-substrate demand, the co-substrate being a redox mediator. Elevated concentrations of Proteus vulgaris, either as free cells or immobilised in Lentikat disks, were incubated with an excess of redox mediator (potassium hexacyanoferrate(III)) and organic substrate for 1h at 37 degrees C without oxygen. The addition of substrate increased the catabolic activity of the microorganisms and the accumulation of reduced mediator, which was subsequently re-oxidised at a working electrode generating a current quantifiable by a coulometric transducer. The recorded currents were converted to their BOD5 equivalent with the only assumption being a fixed conversion of substrate and known stoichiometry. Measurements are reported both for the BOD5 calibration standard solution (150 mg l(-1) glucose, 150 mg l(-1) glutamic acid) and for filtered effluent sampled from a wastewater treatment plant. The inclusion of a highly soluble mediator in place of oxygen facilitated a high ferricyanide concentration in the incubation, which in turn permitted increased concentrations of microorganisms to be used. This substantially reduced the incubation time, from 5 days to 1h, for the biological oxidation of substrates equivalent to those observed using the standard BOD5 test. Stoichiometric conversion efficiencies for the oxidation of the standard substrate by P. vulgaris were typically 60% for free cells and 35-50% for immobilised cells.

  15. Evolution of Oxygenic Photosynthesis

    NASA Astrophysics Data System (ADS)

    Fischer, Woodward W.; Hemp, James; Johnson, Jena E.

    2016-06-01

    The origin of oxygenic photosynthesis was the most important metabolic innovation in Earth history. It allowed life to generate energy and reducing power directly from sunlight and water, freeing it from the limited resources of geochemically derived reductants. This greatly increased global primary productivity and restructured ecosystems. The release of O2 as an end product of water oxidation led to the rise of oxygen, which dramatically altered the redox state of Earth's atmosphere and oceans and permanently changed all major biogeochemical cycles. Furthermore, the biological availability of O2 allowed for the evolution of aerobic respiration and novel biosynthetic pathways, facilitating much of the richness we associate with modern biology, including complex multicellularity. Here we critically review and synthesize information from the geological and biological records for the origin and evolution of oxygenic photosynthesis. Data from both of these archives illustrate that this metabolism first appeared in early Paleoproterozoic time and, despite its biogeochemical prominence, is a relatively late invention in the context of our planet's history.

  16. Oxygen safety

    MedlinePlus

    ... with electric motors Electric baseboard or space heaters Wood stoves, fireplaces, candles Electric blankets Hairdryers, electric razors, ... Therapy.aspx . Accessed February 9, 2016. National Fire Protection Association. Medical oxygen. Updated July 2013. www.nfpa. ...

  17. Improved arterial oxygenation with biologically variable or fractal ventilation using low tidal volumes in a porcine model of acute respiratory distress syndrome.

    PubMed

    Boker, Abdulaziz; Graham, M Ruth; Walley, Keith R; McManus, Bruce M; Girling, Linda G; Walker, Elizabeth; Lefevre, Gerald R; Mutch, W Alan C

    2002-02-15

    We compared biologically variable ventilation (V (bv); n = 9) with control mode ventilation (V (c); n = 8) at low tidal volume (VT)--initial 6 ml/kg--in a porcine model of acute respiratory distress syndrome (ARDS). Hemodynamics, respiratory gases, airway pressures, and VT data were measured. Static P-V curves were generated at 5 h. Interleukin (IL)-8 and IL-10 were measured in serum and tracheal aspirate. By 5 h, higher Pa(O(2)) (173 +/- 30 mm Hg versus 119 +/- 23 mm Hg; mean +/- SD; p < 0.0001 group x time interaction [G x T]), lower shunt fraction (6 +/- 1% versus 9 +/- 3%; p = 0.0026, G x T) at lower peak airway pressure (21 +/- 2 versus 24 +/- 1 cm H(2)O; p = 0.0342; G x T) occurred with V (bv). IL-8 concentrations in tracheal aspirate and wet:dry weight ratios were inversely related; p = 0.011. With V (c), IL-8 concentrations were 3.75-fold greater at wet:dry weight ratio of 10. IL-10 concentrations did not differ between groups. In both groups, ventilation was on the linear portion of the P-V curve. With V (bv), VT variability demonstrated an inverse power law indicating fractal behavior. In this model of ARDS, V (bv) improved Pa(O(2)) at lower peak airway pressure and IL-8 levels compared with V (c).

  18. Oxygen Generation Assembly Technology Development

    NASA Technical Reports Server (NTRS)

    Bagdigian, Robert; Cloud, Dale

    1999-01-01

    Hamilton Standard Space Systems International (HSSI) is under contract to NASA Marshall Space Flight Center (MSFC) to develop an Oxygen Generation Assembly (OGA) for the International Space Station (ISS). The International Space Station Oxygen Generation Assembly (OGA) electrolyzes potable water from the Water Recovery System (WRS) to provide gaseous oxygen to the Space Station module atmosphere. The OGA produces oxygen for metabolic consumption by crew and biological specimens. The OGA also replenishes oxygen lost by experiment ingestion, airlock depressurization, CO2 venting, and leakage. As a byproduct, gaseous hydrogen is generated. The hydrogen will be supplied at a specified pressure range above ambient to support future utilization. Initially, the hydrogen will be vented overboard to space vacuum. This paper describes the OGA integration into the ISS Node 3. It details the development history supporting the design and describes the OGA System characteristics and its physical layout.

  19. Comparison of dissolved oxygen and aquatic biota between a State 303(d)-listed stream segment and USGS biological reference sites in the San Jacinto River Basin, Texas, 2000

    USGS Publications Warehouse

    Moring, J. Bruce

    2002-01-01

    About 30 percent of the 238 water bodies on the 2000 State of Texas 303(d) list of impaired or threatened waters are included for not meeting optimum conditions for aquatic life (Texas Natural Resource Conservation Commission, 2000). Most of the water bodies on the list were assessed using water-column measures such as concentrations of dissolved oxygen (DO) and total metals as surrogates for aquatic biological data. Many water bodies were listed because of low concentrations of DO or potentially toxic dissolved metals such as lead; ambient toxicity to nonresident (laboratory) aquatic organisms also could have been a reason for listing. The Texas Natural Resource Conservation Commission (TNRCC) has emphasized the use of aquatic biological data to determine if a water body should be included or removed from the 303(d) list. The standards used to determine whether a water body should be on the State 303(d) list generally are statewide standards that have not been adjusted for regional or watershed-scale differences that reflect variability across Texas. Such is the case for DO, which is one of the more common surrogate measures used in the listing of stream segments that do not meet optimum conditions for aquatic life. The statewide minimum concentration of DO to meet optimal conditions for aquatic life is 5.0 milligrams per liter. Many water bodies in Texas with few, if any, anthropogenic influences might have DO concentrations below 5.0 milligrams per liter, especially in the late summer when water temperatures peak and streamflows are at minimums for the year. 

  20. Production and Consumption of Reactive Oxygen Species by Fullerenes

    EPA Science Inventory

    Reactive oxygen species (ROS) are one of the most important intermediates in chemical, photochemical, and biological processes. To understand the environmental exposure and toxicity of fullerenes better, the production and consumption of ROS (singlet oxygen, superoxide, hydrogen ...

  1. Vitreal Oxygenation in Retinal Ischemia Reperfusion

    PubMed Central

    Abdallah, Walid; Ameri, Hossein; Barron, Ernesto; Chader, Gerald J.; Greenbaum, Elias; Hinton, David R.

    2011-01-01

    Purpose. To study the feasibility of anterior vitreal oxygenation for the treatment of acute retinal ischemia. Methods. Twenty rabbits were randomized into an oxygenation group, a sham treatment group, and a no treatment group. Baseline electroretinography (ERG) and preretinal oxygen (Po2) measurements were obtained 3 to 5 days before surgery. Intraocular pressure was raised to 100 mm Hg for 90 minutes and then normalized. The oxygenation group underwent vitreal oxygenation for 30 minutes using intravitreal electrodes. The sham treatment group received inactive electrodes for 30 minutes while there was no intervention for the no treatment group. Preretinal Po2 in the posterior vitreous was measured 30 minutes after intervention or 30 minutes after reperfusion (no treatment group) and on postoperative days (d) 3, 6, 9, and 12. On d14, rabbits underwent ERG and were euthanatized. Results. Mean final (d12) Po2 was 10.64 ± 0.77 mm Hg for the oxygenation group, 2.14 ± 0.61 mm Hg for the sham group, and 1.98 ± 0.63 mm Hg for the no treatment group. On ERG, scotopic b-wave amplitude was significantly preserved in the oxygenation group compared with the other two groups. Superoxide dismutase assay showed higher activity in the operated eyes than in the nonoperated control eyes in the sham treatment group and no treatment group only. Histopathology showed preservation of retinal architecture and choroidal vasculature in the oxygenation group, whereas the sham-treated and nontreated groups showed retinal thinning and choroidal atrophy. Conclusions. In severe total ocular ischemia, anterior vitreal oxygenation supplies enough oxygen to penetrate the retinal thickness, resulting in rescue of the RPE/choriocapillaris that continues to perfuse, hence sparing the retinal tissue from damage. PMID:21051734

  2. [How did the earth's oxygen atmosphere originate?].

    PubMed

    Schäfer, G

    2004-09-01

    The planet earth did not carry an oxygen atmosphere from the beginning. Though oxygen could arise from radiation mediated water splitting, these processes were not efficient enough to create a global gas atmosphere. Oxygen in the latter is a product of the photosynthetic activity of early green organisms. Only after biological mass-formation of oxygen the UV-protective ozone layer could develop, then enabeling life to move from water onto land. This took billions of years. The basics of the processes of biological oxygen liberation and utilization are described in the following as well as the importance of their steady state equilibrium. Also a hint is given to oxygen as a toxic compound though being a chemical prerequisite for aerobic life on earth.

  3. Reversible Oxygenation of Oxygen Transport Proteins.

    ERIC Educational Resources Information Center

    Drain, C. M.; Corden, Barry B.

    1987-01-01

    Describes a lecture demonstration which illustrates changes in the visible spectra of oxygen transport proteins upon reversible oxygen binding. Provides a comparison of the physical characteristics of oxygen storage and transport proteins. Reviews essentials for preparation of the materials. (ML)

  4. A 5-day method for determination of soluble silicon concentrations in nonliquid fertilizer materials using a sodium carbonate-ammonium nitrate extractant followed by visible spectroscopy with heteropoly blue analysis: single-laboratory validation.

    PubMed

    Sebastian, Dennis; Rodrigues, Hugh; Kinsey, Charles; Korndörfer, Gaspar; Pereira, Hamilton; Buck, Guilherme; Datnoff, Lawrence; Miranda, Stephen; Provance-Bowley, Mary

    2013-01-01

    A 5-day method for determining the soluble silicon (Si) concentrations in nonliquid fertilizer products was developed using a sodium carbonate (Na2CO3)-ammonium nitrate (NH4NO3) extractant followed by visible spectroscopy with heteropoly blue analysis at 660 nm. The 5-Day Na2CO3-NH4NO3 Soluble Si Extraction Method can be applied to quantify the plant-available Si in solid fertilizer products at levels ranging from 0.2 to 8.4% Si with an LOD of 0.06%, and LOQ of 0.20%. This Si extraction method for fertilizers correlates well with plant uptake of Si (r2 = 0.96 for a range of solid fertilizers) and is applicable to solid Si fertilizer products including blended products and beneficial substances. Fertilizer materials can be processed as received using commercially available laboratory chemicals and materials at ambient laboratory temperatures. The single-laboratory validation of the 5-Day Na2CO3-NH4NO3 Soluble Si Extraction Method has been approved by The Association of American Plant Food Control Officials for testing nonliquid Si fertilizer products.

  5. Nuclear criticality safety: 5-day training course

    SciTech Connect

    Schlesser, J.A.

    1992-11-01

    This compilation of notes is presented as a source reference for the criticality safety course. It represents the contributions of many people, particularly Tom McLaughlin, the course's primary instructor. At the completion of this training course, the attendee will: be able to define terms commonly used in nuclear criticality safety; be able to appreciate the fundamentals of nuclear criticality safety; be able to identify factors which affect nuclear criticality safety; be able to identify examples of criticality controls as used at Los Alamos; be able to identify examples of circumstances present during criticality accidents; be able to identify examples of computer codes used by the nuclear criticality safety specialist; be able to identify examples of safety consciousness required in nuclear criticality safety.

  6. Nuclear criticality safety: 5-day training course

    SciTech Connect

    Schlesser, J.A.

    1992-11-01

    This compilation of notes is presented as a source reference for the criticality safety course. It represents the contributions of many people, particularly Tom McLaughlin, the course`s primary instructor. At the completion of this training course, the attendee will: be able to define terms commonly used in nuclear criticality safety; be able to appreciate the fundamentals of nuclear criticality safety; be able to identify factors which affect nuclear criticality safety; be able to identify examples of criticality controls as used at Los Alamos; be able to identify examples of circumstances present during criticality accidents; be able to identify examples of computer codes used by the nuclear criticality safety specialist; be able to identify examples of safety consciousness required in nuclear criticality safety.

  7. Apollo Soyuz Mission: 5-Day Report

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The Apollo Soyuz Test Project mission objectives and technical investigations are summarized. Topics discussed include: spacecraft and crew systems performance; joint flight activities; scientific and applications experiments; in-flight demonstrations; biomedical considerations; and mission support performance.

  8. 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

  9. Effects of dilution on dissolved oxygen depletion and microbial populations in the biochemical oxygen demand determination.

    PubMed

    Seo, Kyo Seong; Chang, Ho Nam; Park, Joong Kon; Choo, Kwang-Ho

    2007-09-01

    The biochemical oxygen demand (BOD) value is still a key parameter that can determine the level of organics, particularly the content of biodegradable organics in water. In this work, the effects of sample dilution, which should be done inevitably to get appropriate dissolved oxygen (DO) depletion, on the measurement of 5-day BOD (BOD(5)), was investigated with and without seeding using natural and synthetic water. The dilution effects were also evaluated for water samples taken in different seasons such as summer and winter because water temperature can cause a change in the types of microbial species, thus leading to different oxygen depletion profiles during BOD testing. The predation phenomenon between microbial cells was found to be dependent on the inorganic nutrients and carbon sources, showing a change in cell populations according to cell size after 5-day incubation. The dilution of water samples for BOD determination was linked to changes in the environment for microbial growth such as nutrition. The predation phenomenon between microbial cells was more important with less dilution. BOD(5) increased with the specific amount of inorganic nutrient per microbial mass when the natural water was diluted. When seeding was done for synthetic water samples, the seed volume also affected BOD due to the rate of organic uptake by microbes. BOD(5) increased with the specific bacterial population per organic source supplied at the beginning of BOD measurement. For more accurate BOD measurements, specific guidelines on dilution should be established.

  10. Home Oxygen Therapy

    MedlinePlus

    ... oxygen is rarely delivered in the older large, steel gas cylinders any longer since frequent and costly ... just like the compressed oxygen in the older steel cylinders. An important advantage of liquid oxygen is ...

  11. Annual maximum 5-day rainfall total and maximum number of consecutive dry days over Central America and the Caribbean in the late twenty-first century projected by an atmospheric general circulation model with three different horizontal resolutions

    NASA Astrophysics Data System (ADS)

    Nakaegawa, T.; Kitoh, A.; Murakami, H.; Kusunoki, S.

    2014-04-01

    We simulated changes in annual maximum 5-day rainfall (RX5D) and annual maximum number of consecutive dry days (CDD) in Central America, Mexico, and the Caribbean with three different horizontal resolution atmospheric global general circulation models (AGCMs) and quantified the uncertainty of the projections. The RX5Ds and CDDs were projected to increase in most areas in response to global warming. However, consistent changes were confined to small areas: for RX5D, both coastal zones of northern Mexico and the Yucatan Peninsula; for CDD, the Pacific coastal zone of Mexico, the Yucatan Peninsula, and Guatemala. All three AGCMs projected that RX5Ds and CDDs averaged over only the land area and over the entire area (land and ocean) would increase. The dependence of RX5D probability density functions on the horizontal resolutions was complex. Precipitation unrelated to tropical cyclones was primarily responsible for the projected increases in the frequency of RX5Ds greater than 300 mm.

  12. How plasma induced oxidation, oxygenation, and de-oxygenation influences viability of skin cells

    NASA Astrophysics Data System (ADS)

    Oh, Jun-Seok; Strudwick, Xanthe; Short, Robert D.; Ogawa, Kotaro; Hatta, Akimitsu; Furuta, Hiroshi; Gaur, Nishtha; Hong, Sung-Ha; Cowin, Allison J.; Fukuhara, Hideo; Inoue, Keiji; Ito, Masafumi; Charles, Christine; Boswell, Roderick W.; Bradley, James W.; Graves, David B.; Szili, Endre J.

    2016-11-01

    The effect of oxidation, oxygenation, and de-oxygenation arising from He gas jet and He plasma jet treatments on the viability of skin cells cultured in vitro has been investigated. He gas jet treatment de-oxygenated cell culture medium in a process referred to as "sparging." He plasma jet treatments oxidized, as well as oxygenated or de-oxygenated cell culture medium depending on the dissolved oxygen concentration at the time of treatment. He gas and plasma jets were shown to have beneficial or deleterious effects on skin cells depending on the concentration of dissolved oxygen and other oxidative molecules at the time of treatment. Different combinations of treatments with He gas and plasma jets can be used to modulate the concentrations of dissolved oxygen and other oxidative molecules to influence cell viability. This study highlights the importance of a priori knowledge of the concentration of dissolved oxygen at the time of plasma jet treatment, given the potential for significant impact on the biological or medical outcome. Monitoring and controlling the dynamic changes in dissolved oxygen is essential in order to develop effective strategies for the use of cold atmospheric plasma jets in biology and medicine.

  13. Simultaneous Monitoring of Vascular Oxygenation and Tissue Oxygen Tension of Breast Tumors Under Hyperbaric Oxygen Exposure

    DTIC Science & Technology

    2008-04-01

    15. SUBJECT TERMS Technology Development, Near infrared spectroscopy , Hyperbaric Oxygen Treatment, Tumor Therapy Planning and Prognosis, Tumor...near-infrared spectroscopy and 19F magnetic resonance imaging in rats,” Physics in Medicine and Biology 51, 45-60 (2006). A2. Yueqing Gu, Wei R...infrared spectroscopy ,” Photochemistry and Photobiology 81(4), 1002– 1009 (2005). A3. Jae G. Kim, Mengna Xia, and Hanli Liu, “Hemoglobin extinction

  14. [Antibiotic therapy against acute tonsillopharyngitis in children due to group A beta-hemolytic streptococci: comparison of clinical efficacy, the bactericidal effects, and effects on oral flora between cefditoren pivoxil for 5 days and amoxicillin for 10 days].

    PubMed

    Tsumura, Naoki; Nagai, Kensuke; Hidaka, Hidenobu; Otsu, Yasushi; Tanaka, Yuhei; Ikezawa, Shigeru; Honma, Shinichi; Shindo, Shizuo; Ubukata, Kimiko

    2011-06-01

    We compared the clinical efficacy, the bactericidal effects, effect on the oral microbial flora, and adverse reactions between cefditoren pivoxil (CDTR-PI) for 5 days and amoxicillin (AMPC) for 10 days in children with acute group A beta-hemolytic streptococci (GAS) tonsillopharyngitis, and simultaneously examined the emm genotype and drug susceptibility of the isolated GAS. The results showed that the clinical efficacy was 100% for CDTR-PI and 97.9% for AMPC, with no difference between the two groups, and the bacterial elimination rate was 100% in both groups. No serious adverse event was noted in either group. On the other hand, concerning changes in the oral microbial flora between before and after treatment, the amount of bacteria showed no change in the CDTR-PI group (p = 0.5761) but clearly decreased in the AMPC group (p = 0.0049). This indicates that CDTR-PI does not disturb the oral microbial flora compared with AMPC. Also, the emm types determined in the 112 GAS strains isolated in this study were similar to those that have recently been isolated frequently in Japan. Concerning the drug resistance, none of the isolates showed resistance to beta-lactam antibiotics, but 45% of them were resistant to macrolides. The advantages of short-term treatment are considered to include a lower cost, improvement in drug compliance, decrease in the frequency of the occurrence of adverse reactions, decrease in the frequency of the appearance of drug-resistant strains, and alleviation of the psychological burden of patients and their parents. For these reasons, we conclude that CDTR-PI for 5 days is a useful option for the treatment of acute GAS tonsillopharyngitis in children.

  15. Efficacy and safety profile of combination of tramadol-diclofenac versus tramadol-paracetamol in patients with acute musculoskeletal conditions, postoperative pain, and acute flare of osteoarthritis and rheumatoid arthritis: a Phase III, 5-day open-label study

    PubMed Central

    Chandanwale, Ajay S; Sundar, Subramanian; Latchoumibady, Kaliaperumal; Biswas, Swati; Gabhane, Mukesh; Naik, Manoj; Patel, Kamlesh

    2014-01-01

    Objective We aimed to evaluate the safety and efficacy of a fixed-dose combination (FDC) of tramadol and diclofenac versus a standard approved FDC of tramadol and paracetamol, in patients with acute moderate to severe pain. Methods A total of 204 patients with moderate to severe pain due to acute musculoskeletal conditions (n=52), acute flare of osteoarthritis (n=52), acute flare of rheumatoid arthritis (n=50), or postoperative pain (n=50) were enrolled in the study at baseline. Each disease category was then randomized to receive either of two treatments for 5 days: group A received an FDC of immediate-release tramadol hydrochloride (50 mg) and sustained-release diclofenac sodium (75 mg) (one tablet, twice daily), and group B received an FDC of tramadol hydrochloride (37.5 mg) and paracetamol (325 mg) (two tablets every 4–6 hours, up to a maximum of eight tablets daily). The primary efficacy end points were reductions in pain intensity from baseline at day 3 and day 5 as assessed by a Visual Analog Scale (VAS) score. Results Group A showed a significant reduction in the VAS score for overall pain from baseline on day 3 (P=0.001) and day 5 (P<0.0001) as compared with group B. The combination of tramadol-diclofenac resulted in few mild to moderate adverse events (nausea, vomiting, epigastric pain, and gastritis), which required minimal management, without any treatment discontinuation. The number of adverse events in group A was nine (8.82%) compared with 22 (21.78%) in group B, after 5 days of treatment. Conclusion An FDC of tramadol-diclofenac showed a significantly greater reduction in pain intensity and was well tolerated compared with tramadol-paracetamol, resulting in better analgesia in patients suffering from moderate to severe pain due to acute musculoskeletal conditions, postoperative pain following orthopedic surgery, or acute flare of osteoarthritis and rheumatoid arthritis. PMID:25152629

  16. Artificial oxygen transport protein

    DOEpatents

    Dutton, P. Leslie

    2014-09-30

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

  17. Oxygen sensing and signaling.

    PubMed

    van Dongen, Joost T; Licausi, Francesco

    2015-01-01

    Oxygen is an indispensable substrate for many biochemical reactions in plants, including energy metabolism (respiration). Despite its importance, plants lack an active transport mechanism to distribute oxygen to all cells. Therefore, steep oxygen gradients occur within most plant tissues, which can be exacerbated by environmental perturbations that further reduce oxygen availability. Plants possess various responses to cope with spatial and temporal variations in oxygen availability, many of which involve metabolic adaptations to deal with energy crises induced by low oxygen. Responses are induced gradually when oxygen concentrations decrease and are rapidly reversed upon reoxygenation. A direct effect of the oxygen level can be observed in the stability, and thus activity, of various transcription factors that control the expression of hypoxia-induced genes. Additional signaling pathways are activated by the impact of oxygen deficiency on mitochondrial and chloroplast functioning. Here, we describe the molecular components of the oxygen-sensing pathway.

  18. All biology is computational biology

    PubMed Central

    2017-01-01

    Here, I argue that computational thinking and techniques are so central to the quest of understanding life that today all biology is computational biology. Computational biology brings order into our understanding of life, it makes biological concepts rigorous and testable, and it provides a reference map that holds together individual insights. The next modern synthesis in biology will be driven by mathematical, statistical, and computational methods being absorbed into mainstream biological training, turning biology into a quantitative science. PMID:28278152

  19. All biology is computational biology.

    PubMed

    Markowetz, Florian

    2017-03-01

    Here, I argue that computational thinking and techniques are so central to the quest of understanding life that today all biology is computational biology. Computational biology brings order into our understanding of life, it makes biological concepts rigorous and testable, and it provides a reference map that holds together individual insights. The next modern synthesis in biology will be driven by mathematical, statistical, and computational methods being absorbed into mainstream biological training, turning biology into a quantitative science.

  20. Metabolomic analysis to define and compare the effects of PAHs and oxygenated PAHs in developing zebrafish

    PubMed Central

    Elie, Marc R.; Choi, Jaewoo; Nkrumah-Elie, Yasmeen M.; Gonnerman, Gregory D.; Stevens, Jan F.; Tanguay, Robert L.

    2015-01-01

    Polycyclic aromatic hydrocarbons (PAHs) and their oxygenated derivatives are ubiquitously present in diesel exhaust, atmospheric particulate matter and soils sampled in urban areas. Therefore, inhalation or non-dietary ingestion of both PAHs and oxy-PAHs are major routes of exposure for people; especially young children living in these localities. While there has been extensive research on the parent PAHs, limited studies exist on the biological effects of oxy-PAHs which have been shown to be more soluble and more mobile in the environment. Additionally, investigations comparing the metabolic responses resulting from parent PAHs and oxy-PAHs exposures have not been reported. To address these current gaps, an untargeted metabolomics approach was conducted to examine the in vivo metabolomic profiles of developing zebrafish (Danio rerio) exposed to 4 µM of benz[a]anthracene (BAA) or benz[a]anthracene-7, 12-dione (BAQ). By integrating multivariate, univariate and pathway analyses, a total of 62 metabolites were significantly altered after 5 days of exposure. The marked perturbations revealed that both BAA and BAQ affect protein biosynthesis, mitochondrial function, neural development, vascular development and cardiac function. Our previous transcriptomic and genomic data were incorporated in this metabolomics study to provide a more comprehensive view of the relationship between PAH and oxy-PAH exposures on vertebrate development. PMID:26001975

  1. Oxygen chemisorption cryogenic refrigerator

    NASA Technical Reports Server (NTRS)

    Jones, Jack A. (Inventor)

    1987-01-01

    The present invention relates to a chemisorption compressor cryogenic refrigerator which employs oxygen to provide cooling at 60 to 100 K. The invention includes dual vessels containing an oxygen absorbent material, alternately heated and cooled to provide a continuous flow of high pressure oxygen, multiple heat exchangers for precooling the oxygen, a Joule-Thomson expansion valve system for expanding the oxygen to partially liquefy it and a liquid oxygen pressure vessel. The primary novelty is that, while it was believed that once oxygen combined with an element or compound the reaction could not reverse to release gaseous oxygen, in this case oxygen will indeed react in a reversible fashion with certain materials and will do so at temperatures and pressures which make it practical for incorporation into a cryogenic refrigeration system.

  2. Application of integrated ozone biological aerated filters and membrane filtration in water reuse of textile effluents.

    PubMed

    He, Yaozhong; Wang, Xiaojun; Xu, Jinling; Yan, Jinli; Ge, Qilong; Gu, Xiaoyang; Jian, Lei

    2013-04-01

    A combined process including integrated ozone-BAFs (ozone biological aerated filters) and membrane filtration was first applied for recycling textile effluents in a cotton textile mill with capacity of 5000 m(3)/d. Influent COD (chemical oxygen demand) in the range of 82-120 mg/L, BOD5 (5-day biochemical oxygen demand) of 12.6-23.1 mg/L, suspended solids (SSs) of 38-52 mg/L and color of 32-64° were observed during operation. Outflows with COD≤45 mg/L, BOD5≤7.6 mg/L, SS≤15 mg/L, color≤8° were obtained after being decontaminated by ozone-BAF with ozone dosage of 20-25 mg/L. Besides, the average removal rates of PVA (polyvinyl alcohol) and UV254 were 100% and 73.4% respectively. Permeate water produced by RO (reverse osmosis) could be reused in dyeing and finishing processes, while the RO concentrates could be discharged directly under local regulations with COD≤100 mg/L, BOD5≤21 mg/L, SS≤52 mg/L, color≤32°. Results showed that the combined process could guarantee water reuse with high quality, and solve the problem of RO concentrate disposal.

  3. Solid state oxygen sensor

    DOEpatents

    Garzon, F.H.; Chung, B.W.; Raistrick, I.D.; Brosha, E.L.

    1996-08-06

    Solid state oxygen sensors are provided with a yttria-doped zirconia as an electrolyte and use the electrochemical oxygen pumping of the zirconia electrolyte. A linear relationship between oxygen concentration and the voltage arising at a current plateau occurs when oxygen accessing the electrolyte is limited by a diffusion barrier. A diffusion barrier is formed herein with a mixed electronic and oxygen ion-conducting membrane of lanthanum-containing perovskite or zirconia-containing fluorite. A heater may be used to maintain an adequate oxygen diffusion coefficient in the mixed conducting layer. 4 figs.

  4. Solid state oxygen sensor

    DOEpatents

    Garzon, Fernando H.; Chung, Brandon W.; Raistrick, Ian D.; Brosha, Eric L.

    1996-01-01

    Solid state oxygen sensors are provided with a yttria-doped zirconia as an electrolyte and use the electrochemical oxygen pumping of the zirconia electrolyte. A linear relationship between oxygen concentration and the voltage arising at a current plateau occurs when oxygen accessing the electrolyte is limited by a diffusion barrier. A diffusion barrier is formed herein with a mixed electronic and oxygen ion-conducting membrane of lanthanum-containing perovskite or zirconia-containing fluorite. A heater may be used to maintain an adequate oxygen diffusion coefficient in the mixed conducting layer.

  5. Factors controlling oxygen utilization.

    PubMed

    Biaglow, John; Dewhirst, Mark; Leeper, Dennis; Burd, Randy; Tuttle, Steve

    2005-01-01

    We demonstrate, theoretically, that oxygen diffusion distance is related to the metabolic rate of tumors (QO2) as well as the oxygen tension. The difference in QO2 rate between tumors can vary by as much as 80-fold. Inhibition of oxygen utilization by glucose or chemical inhibitors can improve the diffusion distance. Combining respiratory inhibitors with increased availability of oxygen will further improve the oxygen diffusion distance for all tumors. A simple means for inhibiting oxygen consumption is the use of glucose (the Crabtree effect). The inhibition of tumor oxygen utilization by glucose occurs in R323OAc mammary carcinoma and 9L glioma cells. However, stimulation of oxygen consumption is observed with glucose in the Q7 hepatoma cell line. MIBG, a known inhibitor of oxygen utilization, blocks oxygen consumption in 9L, but is weakly inhibitory with the Q7. Q7 tumor cells demonstrate an anomalous behavior of glucose and MIBG on oxygen consumption. Our results clearly demonstrate the necessity for comparing effects of different agents on different tumor cells. Generalizations cannot be made with respect to the choice of inhibitor for in vivo use. Our work shows that oxygen consumption also can be inhibited with malonate and chlorosuccinate. These substrates may be effective in vivo, where glucose is low and glutamine is the major substrate. Our results indicate that information about individual tumor substrate-linked metabolic controls may be necessary before attempting to inhibit oxygen utilization in vivo for therapeutic benefit.

  6. Biological hydrogen photoproduction

    SciTech Connect

    Nemoto, Y.

    1995-09-01

    Following are the major accomplishments of the 6th year`s study of biological hydrogen photoproduction which were supported by DOE/NREL. (1) We have been characterizing a biological hydrogen production system using synchronously growing aerobically nitrogen-fixing unicellular cyanobacterium, Synechococcus sp. Miami BG 043511. So far it was necessary to irradiate the cells to produce hydrogen. Under darkness they did not produce hydrogen. However, we found that, if the cells are incubated with oxygen, they produce hydrogen under the dark. Under 80% argon + 20% oxygen condition, the hydrogen production activity under the dark was about one third of that under the light + argon condition. (2) Also it was necessary so far to incubate the cells under argon atmosphere to produce hydrogen in this system. Argon treatment is very expensive and should be avoided in an actual hydrogen production system. We found that, if the cells are incubated at a high cell density and in a container with minimum headspace, it is not necessary to use argon for the hydrogen production. (3) Calcium ion was found to play an important role in the mechanisms of protection of nitrogenase from external oxygen. This will be a clue to understand the reason why the hydrogen production is so resistant to oxygen in this strain. (4) In this strain, sulfide can be used as electron donor for the hydrogen production. This result shows that waste water can be used for the hydrogen production system using this strain.

  7. Hyperbaric oxygen therapy

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/002375.htm Hyperbaric oxygen therapy To use the sharing features on this page, please enable JavaScript. Hyperbaric oxygen therapy uses a special pressure chamber to increase ...

  8. 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.

  9. Oxygen evolution reaction catalysis

    DOEpatents

    Haber, Joel A.; Jin, Jian; Xiang, Chengxiang; Gregoire, John M.; Jones, Ryan J.; Guevarra, Dan W.; Shinde, Aniketa A.

    2016-09-06

    An Oxygen Evolution Reaction (OER) catalyst includes a metal oxide that includes oxygen, cerium, and one or more second metals. In some instances, the cerium is 10 to 80 molar % of the metals in the metal oxide and/or the catalyst includes two or more second metals. The OER catalyst can be included in or on an electrode. The electrode can be arranged in an oxygen evolution system such that the Oxygen Evolution Reaction occurs at the electrode.

  10. Oxygen boost pump study

    NASA Technical Reports Server (NTRS)

    1975-01-01

    An oxygen boost pump is described which can be used to charge the high pressure oxygen tank in the extravehicular activity equipment from spacecraft supply. The only interface with the spacecraft is the +06 6.205 Pa supply line. The breadboard study results and oxygen tank survey are summarized and the results of the flight-type prototype design and analysis are presented.

  11. Oxygen sensitive microwells.

    PubMed

    Sinkala, Elly; Eddington, David T

    2010-12-07

    Oxygen tension is critical in a number of cell pathways but is often overlooked in cell culture. One reason for this is the difficulty in modulating and assessing oxygen tensions without disturbing the culture conditions. Toward this end, a simple method to generate oxygen-sensitive microwells was developed through embossing polystyrene (PS) and platinum(ii) octaethylporphyrin ketone (PtOEPK) thin films. In addition to monitoring the oxygen tension, microwells were employed in order to isolate uniform clusters of cells in microwells. The depth and width of the microwells can be adapted to different experimental parameters easily by altering the thin film processing or embossing stamp geometries. The thin oxygen sensitive microwell substrate is also compatible with high magnification modalities such as confocal imaging. The incorporation of the oxygen sensor into the microwells produces measurements of the oxygen tension near the cell surface. The oxygen sensitive microwells were calibrated and used to monitor oxygen tensions of Madin-Darby Canine Kidney Cells (MDCKs) cultured at high and low densities as a proof of concept. Wells 500 µm in diameter seeded with an average of 330 cells exhibited an oxygen level of 12.6% whereas wells seeded with an average of 20 cells per well exhibited an oxygen level of 19.5%, a 35.7% difference. This platform represents a new tool for culturing cells in microwells in a format amenable to high magnification imaging while monitoring the oxygen state of the culture media.

  12. Indicators: Dissolved Oxygen

    EPA Pesticide Factsheets

    Dissolved oxygen (DO) is the amount of oxygen that is present in water. It is an important measure of water quality as it indicates a water body's ability to support aquatic life. Water bodies receive oxygen from the atmosphere and from aquatic plants.

  13. Hypoxemia (Low Blood Oxygen)

    MedlinePlus

    Symptoms Hypoxemia (low blood oxygen) By Mayo Clinic Staff Hypoxemia is a below-normal level of oxygen in your blood, specifically in the arteries. Hypoxemia ... of breath. Hypoxemia is determined by measuring the oxygen level in a blood sample taken from an ...

  14. Biological Technicians

    MedlinePlus

    ... Biological technicians typically need a bachelor’s degree in biology or a closely related field. It is important ... Biological technicians typically need a bachelor’s degree in biology or a closely related field. It is important ...

  15. Release time of residual oxygen after dental bleaching with 35% hydrogen peroxide: effect of a catalase-based neutralizing agent.

    PubMed

    Guasso, Bárbara; Salomone, Paloma; Nascimento, Paulo Cícero; Pozzobon, Roselaine Terezinha

    2016-01-01

    This article assessed the effect of a catalase-based agent on residual oxygen (O2) release from teeth exposed to 35% hydrogen peroxide (H2O2). The use of the catalase-based neutralizer agent for 2-3 minutes was able to release residual O2 5 days after exposure to a 35% H2O2-based bleaching gel.

  16. Tested Demonstrations: A Simple Demonstration of Reversible Oxygenation.

    ERIC Educational Resources Information Center

    Kildahl, Nicholas K.

    1983-01-01

    Materials needed, reaction involved, and potential hazards are provided for a demonstration of reversible oxygenation. Also discusses the importance of the reaction in biological systems, focusing on hemoglobin/myoglobin and their function in mammals. (JM)

  17. Analysis of nitrogenous and algal oxygen demand in effluent from a system of aerated lagoons followed by polishing pond.

    PubMed

    Khorsandi, Hassan; Alizadeh, Rahimeh; Tosinejad, Horiyeh; Porghaffar, Hadi

    2014-01-01

    In this descriptive-analytical study, nitrogenous and algal oxygen demand were assessed for effluent from a system of facultative partially mixed lagoons followed by the polishing pond using 120 grab samples over 1 year. Filtered and non-filtered samples of polishing pond effluent were tested in the presence and absence of a nitrification inhibitor. Effective factors, including 5-day biochemical and chemical oxygen demand (BOD and COD), total suspended solids (TSS), dissolved oxygen, chlorophyll A, and temperature, were measured using standard methods for water and wastewater tests. The results were analyzed using repeated measures analysis of variance with SPSS version 16. Findings show that the annual mean of the total 5-day BOD in the effluent from the polishing pond consisted of 44.92% as the algal carbonaceous biochemical oxygen demand (CBOD), 43.61% as the nitrogenous biochemical oxygen demand (NBOD), and 11.47% as the soluble CBOD. According to this study, the annual mean ratios of algal COD and 5-day algal CBOD to TSS were 0.8 and 0.37, respectively. As the results demonstrate, undertaking quality evaluation of the final effluent from the lagoons without considering nitrogenous and algal oxygen demand would undermine effluent quality assessment and interpretation of the performance of the wastewater treatment plant.

  18. A 5-day cytoreductive chemotherapy followed by haplo-identical hsct (FA5-BUCY) as a tumor-ablative regimen improved the survival of patients with advanced hematological malignancies

    PubMed Central

    Chen, Ping; Yuan, Xiaohong; Luo, Xiaofeng; Liu, Tingbo; Zheng, Jing; Zheng, Zhihong; Zheng, Xiaoyun; Chen, Xinji; Zhang, Langhui; Zheng, Hao; Chen, Zaisheng; Hua, Xueling; Le, Shaohua; Li, Jian; Chen, Zhizhe; Hu, Jianda

    2016-01-01

    Haplo-HSCT has been used when HLA-matched siblings are not available. Conditioning regimens aim to reduce tumor burden prior to HSCT and provide sufficient immunoablation. We report the outcome of haplo-HSCT in 63 consecutive patients from 2/2013 to 12/2015 (19 females/44 males) with high-risk or relapsed/refractory hematological malignancies (n=29-AML; 8-sAML; 19-ALL; 5-advanced-MDS; 2-CML-BC). Median age was 20 years (range: 1.1-49). Twenty-one patients achieved remission prior to transplant, while 42 did not. Patients received FA5-BUCY, i.e., 5-day salvage chemotherapy (Fludarabine/Ara-C) and conditioning (Busulfan/Cyclophosphamide). GvHD prophylaxis included ATG, CsA, MMF and short-term MTX. All patients received stem cells from bone marrow and peripheral blood, and achieved successful engraftment, except two who died before. With a median follow-up of 269 days (120-1081), 42/63 patients are still alive and disease-free. Two-year OS and RFS were similar in patients not in remission and in those in complete remission (61.3% vs 56.3%, p=0.88; 58.3% vs 56.3%, p=0.991). Non-relapse mortality and relapse incidence were 22.2% and 11.1%, respectively. Severe acute-GvHD occurred in 4/63 patients. Transplant-related mortality was low at day+100 (17.5%) and for the entire study period (20.6%). Unexpectedly, few patients experienced mild-to-moderate toxicity, and main causes of death were infection and GvHD. BM blast counts, age, and donor-recipient gender-pairs did not affect the outcome. Less chemotherapy cycles prior to HSCT might result in more favorable outcome. Thus, haplo-HSCT with FA5-BUCY appears promising for advanced disease, especially when TBI and amsacrine, used for FLAMSA, are not available and in pediatric patients for whom TBI is not recommended. PMID:27705929

  19. Balancing the generation and elimination of reactive oxygen species

    USGS Publications Warehouse

    Rodriguez, Rusty; Redman, Regina

    2005-01-01

    Fossil records suggest that bacteria developed the ability to photosynthesize ≈3,500 million years ago (mya), initiating a very slow accumulation of atmospheric oxygen (1). Recent geochemical models suggest that atmospheric oxygen did not accumulate to levels conducive for aerobic life until 500–1,000 mya (2, 3). The oxygenation of Earth's atmosphere resulted in the emergence of aerobic organisms followed by a great diversification of biological species and the eventual evolution of humans.

  20. Singlet oxygen in photosensitization.

    PubMed

    Moan, Johan; Juzenas, Petras

    2006-01-01

    Oxygen is a ubiquitous element and a vitally important substance for life on the Earth, and especially for human life. Living organisms need oxygen for most, if not all, of their cellular functions. On the other hand, oxygen can produce metabolites that are toxic and potentially lethal to the same cells. Being reactive and chemically unstable reactive oxygen species (ROS) are the most important metabolites that initiate reduction and oxidation (redox) reactions under physiological conditions. Oxygen in its excited singlet state (1O2) is probably the most important intermediate in such reactions. Since the discovery of oxygen by Joseph Priestley in 1775 it has been recognized that oxygen can be both beneficial and harmful to life.

  1. 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.

  2. 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.

  3. 42 CFR 414.226 - Oxygen and oxygen equipment.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 3 2012-10-01 2012-10-01 false Oxygen and oxygen equipment. 414.226 Section 414... Durable Medical Equipment and Prosthetic and Orthotic Devices § 414.226 Oxygen and oxygen equipment. (a) Payment rules—(1) Oxygen equipment. Payment for rental of oxygen equipment is made based on a monthly...

  4. 42 CFR 414.226 - Oxygen and oxygen equipment.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 3 2011-10-01 2011-10-01 false Oxygen and oxygen equipment. 414.226 Section 414... Equipment and Prosthetic and Orthotic Devices § 414.226 Oxygen and oxygen equipment. (a) Payment rules—(1) Oxygen equipment. Payment for rental of oxygen equipment is made based on a monthly fee schedule...

  5. 42 CFR 414.226 - Oxygen and oxygen equipment.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 3 2013-10-01 2013-10-01 false Oxygen and oxygen equipment. 414.226 Section 414... Durable Medical Equipment and Prosthetic and Orthotic Devices § 414.226 Oxygen and oxygen equipment. (a) Payment rules—(1) Oxygen equipment. Payment for rental of oxygen equipment is made based on a monthly...

  6. 42 CFR 414.226 - Oxygen and oxygen equipment.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 3 2014-10-01 2014-10-01 false Oxygen and oxygen equipment. 414.226 Section 414... Durable Medical Equipment, Prosthetic and Orthotic Devices, and Surgical Dressings § 414.226 Oxygen and oxygen equipment. (a) Payment rules—(1) Oxygen equipment. Payment for rental of oxygen equipment is...

  7. 42 CFR 414.226 - Oxygen and oxygen equipment.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 3 2010-10-01 2010-10-01 false Oxygen and oxygen equipment. 414.226 Section 414... Equipment and Prosthetic and Orthotic Devices § 414.226 Oxygen and oxygen equipment. (a) Payment rules—(1) Oxygen equipment. Payment for rental of oxygen equipment is made based on a monthly fee schedule...

  8. Chapter A7. Biological Indicators

    USGS Publications Warehouse

    Myers, Donna N.; Wilde, Franceska D.

    2003-01-01

    The National Field Manual for the Collection of Water-Quality Data (National Field Manual) provides guidelines and standard procedures for U.S. Geological Survey (USGS) personnel who collect data used to assess the quality of the Nation's surface-water and ground-water resources. This chapter of the manual includes procedures for the (1) determination of biochemical oxygen demand using a 5-day bioassay test; (2) collection, identification, and enumeration of fecal indicator bacteria; (3) collection of samples and information on two laboratory methods for fecal indicator viruses (coliphages); and (4) collection of samples for protozoan pathogens. Each chapter of the National Field Manual is published separately and revised periodically. Newly published and revised chapters are posted on the World Wide Web on the USGS page 'National Field Manual for the Collection of Water-Quality Data.' The URL for this page is http://pubs.water.usgs.gov/twri9A/ (accessed November 25, 2003).

  9. Biological Filters.

    ERIC Educational Resources Information Center

    Klemetson, S. L.

    1978-01-01

    Presents the 1978 literature review of wastewater treatment. The review is concerned with biological filters, and it covers: (1) trickling filters; (2) rotating biological contractors; and (3) miscellaneous reactors. A list of 14 references is also presented. (HM)

  10. Biological Treatment of Groundwater Contaminated with Mixtures of Aromatic Compounds

    DTIC Science & Technology

    1993-03-01

    bioreactor to biodegrade chlorinated aromatic compounds. The site at Kelly AFB, TX is an abandoned waste storage area where the soil and groundwater is...scale submerged fixed- film bioreactors were tested with groundwater containing benzene, naphthalene, phenol, toluene, ortho and para- cresol , 2,4...strain JS150 could aerobically biodegrade complex mixtures of solvents if appropriate dissolved oxygen levels were maintained. After the initial 5 days

  11. Oxygen ion conducting materials

    DOEpatents

    Vaughey, John; Krumpelt, Michael; Wang, Xiaoping; Carter, J. David

    2005-07-12

    An oxygen ion conducting ceramic oxide that has applications in industry including fuel cells, oxygen pumps, oxygen sensors, and separation membranes. The material is based on the idea that substituting a dopant into the host perovskite lattice of (La,Sr)MnO.sub.3 that prefers a coordination number lower than 6 will induce oxygen ion vacancies to form in the lattice. Because the oxygen ion conductivity of (La,Sr)MnO.sub.3 is low over a very large temperature range, the material exhibits a high overpotential when used. The inclusion of oxygen vacancies into the lattice by doping the material has been found to maintain the desirable properties of (La,Sr)MnO.sub.3, while significantly decreasing the experimentally observed overpotential.

  12. Oxygen ion conducting materials

    DOEpatents

    Carter, J. David; Wang, Xiaoping; Vaughey, John; Krumpelt, Michael

    2004-11-23

    An oxygen ion conducting ceramic oxide that has applications in industry including fuel cells, oxygen pumps, oxygen sensors, and separation membranes. The material is based on the idea that substituting a dopant into the host perovskite lattice of (La,Sr)MnO.sub.3 that prefers a coordination number lower than 6 will induce oxygen ion vacancies to form in the lattice. Because the oxygen ion conductivity of (La,Sr)MnO.sub.3 is low over a very large temperature range, the material exhibits a high overpotential when used. The inclusion of oxygen vacancies into the lattice by doping the material has been found to maintain the desirable properties of (La,Sr)MnO.sub.3, while significantly decreasing the experimentally observed overpotential.

  13. Integrated turbomachine oxygen plant

    SciTech Connect

    Anand, Ashok Kumar; DePuy, Richard Anthony; Muthaiah, Veerappan

    2014-06-17

    An integrated turbomachine oxygen plant includes a turbomachine and an air separation unit. One or more compressor pathways flow compressed air from a compressor through one or more of a combustor and a turbine expander to cool the combustor and/or the turbine expander. An air separation unit is operably connected to the one or more compressor pathways and is configured to separate the compressed air into oxygen and oxygen-depleted air. A method of air separation in an integrated turbomachine oxygen plant includes compressing a flow of air in a compressor of a turbomachine. The compressed flow of air is flowed through one or more of a combustor and a turbine expander of the turbomachine to cool the combustor and/or the turbine expander. The compressed flow of air is directed to an air separation unit and is separated into oxygen and oxygen-depleted air.

  14. Oxygen, a paradoxical element?

    PubMed

    Greabu, Maria; Battino, M; Mohora, Maria; Olinescu, R; Totan, Alexandra; Didilescu, Andreea

    2008-01-01

    Oxygen is an essential element for life on earth. No life may exist without oxygen. But in the last forty years, conclusive evidence demonstrated the double-edge sword of this element. In certain conditions, oxygen may produce reactive species, even free radicals. More, the production of reactive oxygen species (ROS) takes place everywhere: in air, nature or inside human bodies. The paradox of oxygen atom is entirely due to its peculiar electronic structure. But life began on earth, only when nature found efficient weapons against ROS, these antioxidants, which all creatures are extensibly endowed with. The consequences of oxygen activation in human bodies are only partly known, in spite of extensive scientific research on theoretical, experimental and clinical domains.

  15. Oxygen ion conducting materials

    DOEpatents

    Vaughey, John; Krumpelt, Michael; Wang, Xiaoping; Carter, J. David

    2003-01-01

    An oxygen ion conducting ceramic oxide that has applications in industry including fuel cells, oxygen pumps, oxygen sensors, and separation membranes. The material is based on the idea that substituting a dopant into the host perovskite lattice of (La,Sr)MnO.sub.3 that prefers a coordination number lower than 6 will induce oxygen ion vacancies to form in the lattice. Because the oxygen ion conductivity of (La,Sr)MnO.sub.3 is low over a very large temperature range, the material exhibits a high overpotential when used. The inclusion of oxygen vacancies into the lattice by doping the material has been found to maintain the desirable properties of (La,Sr)MnO.sub.3, while significantly decreasing the experimentally observed overpotential.

  16. Continuous home oxygen therapy.

    PubMed

    Ortega Ruiz, Francisco; Díaz Lobato, Salvador; Galdiz Iturri, Juan Bautista; García Rio, Francisco; Güell Rous, Rosa; Morante Velez, Fátima; Puente Maestu, Luis; Tàrrega Camarasa, Julia

    2014-05-01

    Oxygen therapy is defined as the therapeutic use of oxygen and consists of administering oxygen at higher concentrations than those found in room air, with the aim of treating or preventing hypoxia. This therapeutic intervention has been shown to increase survival in patients with chronic obstructive pulmonary disease (COPD) and respiratory failure. Although this concept has been extended by analogy to chronic respiratory failure caused by respiratory and non-respiratory diseases, continuous oxygen therapy has not been shown to be effective in other disorders. Oxygen therapy has not been shown to improve survival in patients with COPD and moderate hypoxaemia, nor is there consensus regarding its use during nocturnal desaturations in COPD or desaturations caused by effort. The choice of the oxygen source must be made on the basis of criteria such as technical issues, patient comfort and adaptability and cost. Flow must be adjusted to achieve appropriate transcutaneous oxyhaemoglobin saturation correction.

  17. Atomic Oxygen Effects

    NASA Technical Reports Server (NTRS)

    Miller, Sharon K. R.

    2014-01-01

    Atomic oxygen, which is the most predominant species in low Earth orbit, is highly reactive and can break chemical bonds on the surface of a wide variety of materials leading to volatilization or surface oxidation which can result in failure of spacecraft materials and components. This presentation will give an overview of how atomic oxygen reacts with spacecraft materials, results of space exposure testing of a variety of materials, and examples of failures caused by atomic oxygen.

  18. Aerobic and two-stage anaerobic-aerobic sludge digestion with pure oxygen and air aeration.

    PubMed

    Zupancic, Gregor D; Ros, Milenko

    2008-01-01

    The degradability of excess activated sludge from a wastewater treatment plant was studied. The objective was establishing the degree of degradation using either air or pure oxygen at different temperatures. Sludge treated with pure oxygen was degraded at temperatures from 22 degrees C to 50 degrees C while samples treated with air were degraded between 32 degrees C and 65 degrees C. Using air, sludge is efficiently degraded at 37 degrees C and at 50-55 degrees C. With oxygen, sludge was most effectively degraded at 38 degrees C or at 25-30 degrees C. Two-stage anaerobic-aerobic processes were studied. The first anaerobic stage was always operated for 5 days HRT, and the second stage involved aeration with pure oxygen and an HRT between 5 and 10 days. Under these conditions, there is 53.5% VSS removal and 55.4% COD degradation at 15 days HRT - 5 days anaerobic, 10 days aerobic. Sludge digested with pure oxygen at 25 degrees C in a batch reactor converted 48% of sludge total Kjeldahl nitrogen to nitrate. Addition of an aerobic stage with pure oxygen aeration to the anaerobic digestion enhances ammonium nitrogen removal. In a two-stage anaerobic-aerobic sludge digestion process within 8 days HRT of the aerobic stage, the removal of ammonium nitrogen was 85%.

  19. Elastomer Compatible With Oxygen

    NASA Technical Reports Server (NTRS)

    Martin, Jon W.

    1987-01-01

    Artificial rubber resists ignition on impact and seals at low temperatures. Filled fluoroelastomer called "Katiflex" developed for use in seals of vessels holding cold liquid and gaseous oxygen. New material more compatible with liquid oxygen than polytetrafluoroethylene. Provides dynamic seal at -196 degrees C with only 4 times seal stress required at room temperature. In contrast, conventional rubber seals burn or explode on impact in high-pressure oxygen, and turn hard or even brittle at liquid-oxygen temperatures, do not seal reliably, also see (MFS-28124).

  20. 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.

  1. Monitoring Oxygen Status.

    PubMed

    Toffaletti, J G; Rackley, C R

    Although part of a common "blood gas" test panel with pH and pCO2, the pO2, %O2Hb, and related parameters are independently used to detect and monitor oxygen deficits from a variety of causes. Measurement of blood gases and cooximetry may be done by laboratory analyzers, point of care testing, noninvasive pulse oximetry, and transcutaneous blood gases. The specimen type and mode of monitoring oxygenation that are chosen may be based on a combination of urgency, practicality, clinical need, and therapeutic objectives. Because oxygen concentrations in blood are extremely labile, there are several highly important preanalytical practices necessary to prevent errors in oxygen and cooximetry results. Effective utilization of oxygen requires binding by hemoglobin in the lungs, transport in the blood, and release to tissues, where cellular respiration occurs. Hydrogen ion (pH), CO2, temperature, and 2,3-DPG all play important roles in these processes. Additional measurements and calculations are often used to interpret and locate the cause and source of an oxygen deficit. These include the Hb concentration, Alveolar-arterial pO2 gradient, pO2:FIO2 ratio, oxygenation index, O2 content and O2 delivery, and pulmonary dead space and intrapulmonary shunting. The causes of hypoxemia will be covered and, to illustrate how the oxygen parameters are used clinically in the diagnosis and management of patients with abnormal oxygenation, two clinical cases will be presented and described.

  2. Measuring tissue oxygenation

    NASA Technical Reports Server (NTRS)

    Soyemi, Olusola O. (Inventor); Soller, Babs R. (Inventor); Yang, Ye (Inventor)

    2009-01-01

    Methods and systems for calculating tissue oxygenation, e.g., oxygen saturation, in a target tissue are disclosed. In some embodiments, the methods include: (a) directing incident radiation to a target tissue and determining reflectance spectra of the target tissue by measuring intensities of reflected radiation from the target tissue at a plurality of radiation wavelengths; (b) correcting the measured intensities of the reflectance spectra to reduce contributions thereto from skin and fat layers through which the incident radiation propagates; (c) determining oxygen saturation in the target tissue based on the corrected reflectance spectra; and (d) outputting the determined value of oxygen saturation.

  3. Combination of ozonation, activated carbon, and biological aerated filter for advanced treatment of dyeing wastewater for reuse.

    PubMed

    Zou, Xiao-Ling

    2015-06-01

    Laboratorial scale experiments were performed to investigate and evaluate the performance and removal characteristics of organics, color, and genotoxicity by an integrated process including ozonation, activated carbon (AC), and biological aerated filter (BAF) for recycling biotreated dyeing wastewater (BTDW) collected from a cotton textile factory. Influent chemical oxygen demand (COD) in the range of 156 - 252 mg/L, 5-day biochemical oxygen demand (BOD5) of 13.5 - 21.7 mg/L, and color of 58 - 76° were observed during the 20-day continuous operation. Outflows with average COD of 43 mg/L, BOD5 of 6.6 mg/L, and color of 5.6° were obtained after being decontaminated by the hybrid system with ozone dosage of 0.25 mg O3applied/mg COD0, 40 min ozonation contact time, 30 min hydraulic retention time (HRT) for AC treatment, and 2.5 h HRT for BAF treatment. More than 82 % of the genotoxicity of BTDW was eliminated in the ozonation unit. The genotoxicity of the BAF effluent was less than 1.33 μg 4-nitroquinoline-N-oxide/L. Ozonation could change the organics molecular structures, destroy chromophores, increase the biodegradability, and obviously reduce the genotoxicity of BTDW. Results showed that the combined process could guarantee water reuse with high quality.

  4. Reactive oxygen species in phagocytic leukocytes

    PubMed Central

    2008-01-01

    Phagocytic leukocytes consume oxygen and generate reactive oxygen species in response to appropriate stimuli. The phagocyte NADPH oxidase, a multiprotein complex, existing in the dissociated state in resting cells becomes assembled into the functional oxidase complex upon stimulation and then generates superoxide anions. Biochemical aspects of the NADPH oxidase are briefly discussed in this review; however, the major focus relates to the contributions of various modes of microscopy to our understanding of the NADPH oxidase and the cell biology of phagocytic leukocytes. PMID:18597105

  5. Biology Notes

    ERIC Educational Resources Information Center

    School Science Review, 1977

    1977-01-01

    Includes procedures for demonstrating anaerobic respiration in peas, isolating virgin Drosophila females, solving mortality problems in young gerbils, measuring dissolved oxygen, constructing models for transpiration and DNA molecules, freezing chick embryos, mixing nutrient media, illustrating Darwinian ecological principles, and detecting…

  6. The effects of combined hyperbaric oxygen therapy on patients with post-stroke depression.

    PubMed

    Yan, Dong; Shan, Jin; Ze, Yu; Xiao-Yan, Zeng; Xiao-Hua, Hu

    2015-05-01

    [Purpose] To observe the effect of combined hyperbaric oxygen therapy on patients with post-stroke depression. [Subjects] Ninety patients with post-stroke depression were randomly divided into 3 groups: fluoxetine treatment group (n = 30), hyperbaric oxygen therapy group (n = 30), and hyperbaric oxygen combined treatment group (n = 30). [Methods] Fluoxetine treatment group received anti-depression drugs (fluoxetine, 20 mg/day), hyperbaric oxygen therapy group received hyperbaric oxygen (once a day, 5 days/week), hyperbaric oxygen combined treatment group received fluoxetine and hyperbaric oxygen treatments as described above. All patients received routine rehabilitation therapy. Hamilton Depression Scale (HAMD), and Scandinavian Stroke Scale (SSS) scores were evaluated before and at the end of 4th week. The total effective rate of depression release between the 3 groups was also compared at the end of study. [Results] The end scores of HAMD and SSS in the 3 groups were significantly lower than those before treatment. The total effective rate of combined hyperbaric oxygen therapy group after treatment was higher than the other two groups. [Conclusions] Combined hyperbaric oxygen therapy plays an important role in the treatment of patients with post-stroke depression. The total effective rate of combined hyperbaric oxygen therapy was higher than other routine anti post-stroke depression treatments.

  7. Learning To Breathe: Developmental Phase Transitions in Oxygen Status.

    PubMed

    Considine, Michael J; Diaz-Vivancos, Pedro; Kerchev, Pavel; Signorelli, Santiago; Agudelo-Romero, Patricia; Gibbs, Daniel J; Foyer, Christine H

    2017-02-01

    Plants are developmentally disposed to significant changes in oxygen availability, but our understanding of the importance of hypoxia is almost entirely limited to stress biology. Differential patterns of the abundance of oxygen, nitric oxide ((•)NO), and reactive oxygen species (ROS), as well as of redox potential, occur in organs and meristems, and examples are emerging in the literature of mechanistic relationships of these to development. We describe here the convergence of these cues in meristematic and reproductive tissues, and discuss the evidence for regulated hypoxic niches within which oxygen-, ROS-, (•)NO-, and redox-dependent signalling curate developmental transitions in plants.

  8. Oxygen sensitive paper

    NASA Technical Reports Server (NTRS)

    Whidby, J. F.

    1973-01-01

    Paper is impregnated with mixture of methylene blue and ethylenediaminetetraacetic acid. Methylene blue is photo-reduced to leuco-form. Paper is kept isolated from oxygen until ready for use. Paper can be reused by photo-reduction after oxygen exposure.

  9. Durability of oxygen sensors

    NASA Astrophysics Data System (ADS)

    Snapp, L.

    1985-03-01

    This report describes the results of dynamometer and vehicle durability testing from a variety of sources, as well as common causes of failure for oxygen sensors. The data indicates that oxygen sensors show low failure rates, even at mileages of 80,000 miles and beyond.

  10. Multi-spectral imaging of oxygen saturation

    NASA Astrophysics Data System (ADS)

    Savelieva, Tatiana A.; Stratonnikov, Aleksander A.; Loschenov, Victor B.

    2008-06-01

    The system of multi-spectral imaging of oxygen saturation is an instrument that can record both spectral and spatial information about a sample. In this project, the spectral imaging technique is used for monitoring of oxygen saturation of hemoglobin in human tissues. This system can be used for monitoring spatial distribution of oxygen saturation in photodynamic therapy, surgery or sports medicine. Diffuse reflectance spectroscopy in the visible range is an effective and extensively used technique for the non-invasive study and characterization of various biological tissues. In this article, a short review of modeling techniques being currently in use for diffuse reflection from semi-infinite turbid media is presented. A simple and practical model for use with a real-time imaging system is proposed. This model is based on linear approximation of the dependence of the diffuse reflectance coefficient on relation between absorbance and reduced scattering coefficient. This dependence was obtained with the Monte Carlo simulation of photon propagation in turbid media. Spectra of the oxygenated and deoxygenated forms of hemoglobin differ mostly in the red area (520 - 600 nm) and have several characteristic points there. Thus four band-pass filters were used for multi-spectral imaging. After having measured the reflectance, the data obtained are used for fitting the concentration of oxygenated and free hemoglobin, and hemoglobin oxygen saturation.

  11. Soil gas oxygen tension and pentachlorophenol biodegradation

    SciTech Connect

    Hurst, C.J.; Sims, R.C.; Sims, J.L.; Sorensen, D.L.; McLean, J.E.; Huling, S.

    1997-04-01

    Laboratory tests were conducted to determine the effect of soil gas oxygen concentration on the degradation and mineralization of spiked {sup 14}C-pentachlorophenol and nonlabeled pentachlorophenol (PCP) present in soil taken from a prepared-bed land treatment unit at the Champion International Superfund Site in Libby, Mont. This soil was contaminated with wood preserving wastes including creosote and PCP. Degradation rates of {sup 14}C-PCP and nonlabeled PCP were found to be enhanced under soil gas oxygen concentrations between 2 and 21% in the contaminated soil. Between 48 and 64% of {sup 14}C-PCP spiked onto the soil was mineralized after 70 days at soil gas oxygen levels between 2 and 21%. No statistically significant mineralization of PCP was found to occur at 0% oxygen concentrations. Mineralization of {sup 14}C-PCP in contaminated soil poisoned with mercuric chloride was determined to be less than 0.2%. Degradation of indigenous nonradiolabeled PCP in the nonpoisoned soil was statistically significantly greater than in poisoned soil. These results indicated that degradation of PCP was biological and would occur under low oxygen concentrations. Soil gas oxygen concentrations necessary for PCP biodegradation (2--5%) could be maintained, for example, using bioventing technology in order to achieve continued treatment of buried lifts of soil while new lifts are added, thus decreasing the total time for soil remediation of the prepared bed.

  12. Atomic Oxygen Textured Polymers

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A.; Rutledge, Sharon K.; Hunt, Jason D.; Drobotij, Erin; Cales, Michael R.; Cantrell, Gidget

    1995-01-01

    Atomic oxygen can be used to microscopically alter the surface morphology of polymeric materials in space or in ground laboratory facilities. For polymeric materials whose sole oxidation products are volatile species, directed atomic oxygen reactions produce surfaces of microscopic cones. However, isotropic atomic oxygen exposure results in polymer surfaces covered with lower aspect ratio sharp-edged craters. Isotropic atomic oxygen plasma exposure of polymers typically causes a significant decrease in water contact angle as well as altered coefficient of static friction. Such surface alterations may be of benefit for industrial and biomedical applications. The results of atomic oxygen plasma exposure of thirty-three (33) different polymers are presented, including typical morphology changes, effects on water contact angle, and coefficient of static friction.

  13. Prostaglandins and their receptors in insect biology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We treat the biological significance of prostaglandins (PGs) and their known receptors in insect biology. PGs and related eicosanoids are oxygenated derivatives of arachidonic acid (AA) and two other C20 polyunsaturated fatty acids. PGs are mostly appreciated in the context of biomedicine, but a gr...

  14. Mimicking Oxygen delivery and waste removal functions of blood.

    PubMed

    Zhang, Huaifa; Barralet, Jake E

    2017-02-15

    In addition to immunological and wound healing cell and platelet delivery, ion stasis and nutrient supply, blood delivers oxygen to cells and tissues and removes metabolic wastes. For decades researchers have been trying to develop approaches that mimic these two immediately vital functions of blood. Oxygen is crucial for the long-term survival of tissues and cells in vertebrates. Hypoxia (oxygen deficiency) and even at times anoxia (absence of oxygen) can occur during organ preservation, organ and cell transplantation, wound healing, in tumors and engineering of tissues. Different approaches have been developed to deliver oxygen to tissues and cells, including hyperbaric oxygen therapy (HBOT), normobaric hyperoxia therapy (NBOT), using biochemical reactions and electrolysis, employing liquids with high oxygen solubility, administering hemoglobin, myoglobin and red blood cells (RBCs), introducing oxygen-generating agents, using oxygen-carrying microparticles, persufflation, and peritoneal oxygenation. Metabolic waste accumulation is another issue in biological systems when blood flow is insufficient. Metabolic wastes change the microenvironment of cells and tissues, influence the metabolic activities of cells, and ultimately cause cell death. This review examines advances in blood mimicking systems in the field of biomedical engineering in terms of oxygen delivery and metabolic waste removal.

  15. Atomic Oxygen Fluence Monitor

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A.

    2011-01-01

    This innovation enables a means for actively measuring atomic oxygen fluence (accumulated atoms of atomic oxygen per area) that has impinged upon spacecraft surfaces. Telemetered data from the device provides spacecraft designers, researchers, and mission managers with real-time measurement of atomic oxygen fluence, which is useful for prediction of the durability of spacecraft materials and components. The innovation is a compact fluence measuring device that allows in-space measurement and transmittance of measured atomic oxygen fluence as a function of time based on atomic oxygen erosion yields (the erosion yield of a material is the volume of material that is oxidized per incident oxygen atom) of materials that have been measured in low Earth orbit. It has a linear electrical response to atomic oxygen fluence, and is capable of measuring high atomic oxygen fluences (up to >10(exp 22) atoms/sq cm), which are representative of multi-year low-Earth orbital missions (such as the International Space Station). The durability or remaining structural lifetime of solar arrays that consist of polymer blankets on which the solar cells are attached can be predicted if one knows the atomic oxygen fluence that the solar array blanket has been exposed to. In addition, numerous organizations that launch space experiments into low-Earth orbit want to know the accumulated atomic oxygen fluence that their materials or components have been exposed to. The device is based on the erosion yield of pyrolytic graphite. It uses two 12deg inclined wedges of graphite that are over a grit-blasted fused silica window covering a photodiode. As the wedges erode, a greater area of solar illumination reaches the photodiode. A reference photodiode is also used that receives unobstructed solar illumination and is oriented in the same direction as the pyrolytic graphite covered photodiode. The short-circuit current from the photodiodes is measured and either sent to an onboard data logger, or

  16. Drivers of summer oxygen depletion in the central North Sea

    NASA Astrophysics Data System (ADS)

    Queste, B. Y.; Fernand, L.; Jickells, T. D.; Heywood, K. J.; Hind, A. J.

    2015-06-01

    In stratified shelf seas, oxygen depletion beneath the thermocline is a result of a greater rate of biological oxygen demand than the rate of supply of oxygenated water. Suitably equipped gliders are uniquely placed to observe both the supply through the thermocline and the consumption of oxygen in the bottom layers. A Seaglider was deployed in the shallow (≈ 100 m) stratified North Sea in a region of known low oxygen during August 2011 to investigate the processes regulating supply and consumption of dissolved oxygen below the pycnocline. The first deployment of such a device in this area, it provided extremely high resolution observations, 316 profiles (every 16 min, vertical resolution of 1 m) of CTD, dissolved oxygen concentrations, backscatter and fluorescence during a three day deployment. The high temporal resolution observations revealed occasional small scale events that supply oxygenated water into the bottom layer at a rate of 2±1 μmol dm-3 day-1. Benthic and pelagic oxygen sinks, quantified through glider observations and past studies, indicate more gradual background consumption rates of 2.5±1 μmol dm-3 day-1. This budget revealed that the balance of oxygen supply and demand is in agreement with previous studies of the North Sea. However, the glider data show a net oxygen consumption rate of 2.8±0.3 μmol dm-3 day-1 indicating a localised or short-lived increase in oxygen consumption rates. This high rate of oxygen consumption is indicative of an unidentified oxygen sink. We propose that this elevated oxygen consumption is linked to localised depocentres and rapid remineralisation of resuspensded organic matter. The glider proved to be an excellent tool for monitoring shelf sea processes despite challenges to glider flight posed by high tidal velocities, shallow bathymetry, and very strong density gradients. The direct observation of these processes allows more up to date rates to be used in the development of ecosystem models.

  17. Synthetic carriers of oxygen.

    PubMed

    Dellacherie, E; Labrude, P; Vigneron, C; Riess, J G

    1987-01-01

    During the last decade, construction of artificial carriers of oxygen for transfusion purposes has evolved in three main directions, which can be reviewed as follows. The first approach consists of modifying hemoglobin (Hb), the natural oxygen carrier, in order to lower its oxygen affinity and increase its intravascular persistence. To achieve this aim, two basic procedures have been used: molecular and environmental modification. In the first case, Hb is modified with chemical reagents; the second requires encapsulation of Hb to obtain artificial erythrocytes. The second approach is based on the use of synthetic oxygen-carrying chelates that mimic the oxygenation function of Hb. The main products in this class are metalloporphyrins, whose chemical environment is designed to render them efficient as reversible carriers of oxygen in vivo. Finally, the third approach deals with the perfluorochemicals used in emulsified form. Perfluorochemical liquids are excellent gas solvents, but some problems remain unsolved with regard to their development as oxygen carriers in vivo: low O2 dissolving capacity, toxicity, and excretion.

  18. Electrochemical oxygen concentrator as an oxygen compressor

    NASA Technical Reports Server (NTRS)

    1975-01-01

    A solid polymer electrolyte (SPE) oxygen compressor is described which generates pressures of 3000 psi. The SPE is a cation exchange membrane with chemical compatibility, and has the capability of withstanding 5000 psi. Other features of the compressor described include: gasketless sealing, porus plate cell supports, and conductive cooling. Results are presented of a computer program which defines the power of the system as a function of density, temperature, pressure, membrane thickness, and water content.

  19. Reactive oxygen species in the immune system.

    PubMed

    Yang, Yuhui; Bazhin, Alexandr V; Werner, Jens; Karakhanova, Svetlana

    2013-06-01

    Reactive oxygen species (ROS) are a group of highly reactive chemicals containing oxygen produced either exogenously or endogenously. ROS are related to a wide variety of human disorders, such as chronic inflammation, age-related diseases and cancers. Besides, ROS are also essential for various biological functions, including cell survival, cell growth, proliferation and differentiation, and immune response. At present there are a number of excellent publications including some reviews about functions of these molecules either in normal cell biology or in pathophysiology. In this work, we reviewed available information and recent advances about ROS in the main immune cell types and gave summary about functions of these highly reactive molecules both in innate immunity as conservative defense mechanisms and in essential immune cells involved in adaptive immunity, and particularly in immune suppression.

  20. Improved Intratumoral Oxygenation Through Vascular Normalization Increases Glioma Sensitivity to Ionizing Radiation

    SciTech Connect

    McGee, Mackenzie C.; Hamner, J. Blair; Williams, Regan F.; Rosati, Shannon F.; Sims, Thomas L.; Ng, Catherine Y.; Gaber, M. Waleed; Calabrese, Christopher; Wu Jianrong; Nathwani, Amit C.; Merchant, Thomas E.; Davidoff, Andrew M.

    2010-04-15

    Purpose: Ionizing radiation, an important component of glioma therapy, is critically dependent on tumor oxygenation. However, gliomas are notable for areas of necrosis and hypoxia, which foster radioresistance. We hypothesized that pharmacologic manipulation of the typically dysfunctional tumor vasculature would improve intratumoral oxygenation and, thus, the antiglioma efficacy of ionizing radiation. Methods and Materials: Orthotopic U87 xenografts were treated with either continuous interferon-beta (IFN-beta) or bevacizumab, alone, or combined with cranial irradiation (RT). Tumor growth was assessed by quantitative bioluminescence imaging; the tumor vasculature using immunohistochemical staining, and tumor oxygenation using hypoxyprobe staining. Results: Both IFN-beta and bevaziumab profoundly affected the tumor vasculature, albeit with different cellular phenotypes. IFN-beta caused a doubling in the percentage of area of perivascular cell staining, and bevacizumab caused a rapid decrease in the percentage of area of endothelial cell staining. However, both agents increased intratumoral oxygenation, although with bevacizumab, the effect was transient, being lost by 5 days. Administration of IFN-beta or bevacizumab before RT was significantly more effective than any of the three modalities as monotherapy or when RT was administered concomitantly with IFN-beta or bevacizumab or 5 days after bevacizumab. Conclusion: Bevacizumab and continuous delivery of IFN-beta each induced significant changes in glioma vascular physiology, improving intratumoral oxygenation and enhancing the antitumor activity of ionizing radiation. Additional investigation into the use and timing of these and other agents that modify the vascular phenotype, combined with RT, is warranted to optimize cytotoxic activity.

  1. Is synthetic biology mechanical biology?

    PubMed

    Holm, Sune

    2015-12-01

    A widespread and influential characterization of synthetic biology emphasizes that synthetic biology is the application of engineering principles to living systems. Furthermore, there is a strong tendency to express the engineering approach to organisms in terms of what seems to be an ontological claim: organisms are machines. In the paper I investigate the ontological and heuristic significance of the machine analogy in synthetic biology. I argue that the use of the machine analogy and the aim of producing rationally designed organisms does not necessarily imply a commitment to mechanical biology. The ideal of applying engineering principles to biology is best understood as expressing recognition of the machine-unlikeness of natural organisms and the limits of human cognition. The paper suggests an interpretation of the identification of organisms with machines in synthetic biology according to which it expresses a strategy for representing, understanding, and constructing living systems that are more machine-like than natural organisms.

  2. Oxygen cycling in the northern Benguela Upwelling System: Modelling oxygen sources and sinks

    NASA Astrophysics Data System (ADS)

    Schmidt, Martin; Eggert, Anja

    2016-12-01

    This paper elucidates the oxygen dynamics in the northern Benguela Upwelling System by means of process oriented, numerical modelling. Owing to the complex physical-biological interaction in this system, a coupled hydrodynamic-biogeochemical model is required to grasp the various aspects of the oxygen dynamics. We used high-resolution atmospheric fields derived from observations to force our model, available since 1999. The model results represent a 15 years, consistent data set of realistic hydrographic and ecosystem variables, including oxygen distribution patterns. After a concise description of the main aspects of the model, we use the model data to analyse the components contributing to the oxygen dynamics, namely, the ocean circulation, the exchange between ocean and atmosphere as well as the local biogeochemical oxygen cycling in the system. We thoroughly validate the model with available field observations and remote sensing data. The strengths of coastal upwelling, which controls the nutrient supply to the euphotic zone, as well as the poleward undercurrent that carries oxygen and nutrients to the shelf in the northern Benguela Upwelling System are well reproduced in the model. Among the biological oxygen sinks, mineralisation in the sediment, respiration of zooplankton and nitrification in the water column are important. We also found that vertical migration of zooplankton in response to the oxygen conditions provides a regulating feedback, which may prevent a complete deoxygenation of suboxic waters. As long as oxygen or nitrate are available in the bottom waters, the activities of chemolithoautotrophic sulphur bacteria on the sediment surface keep the redoxcline within the sediment and prevent the release of hydrogen sulphide into the water column. By horizontal integration of the simulated ocean-atmosphere oxygen flux, it can be shown that the Kunene upwelling cell between 16 ° S and 18 ° S is a boundary between the equatorial ocean, characterise by

  3. Biology Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1983

    1983-01-01

    Describes laboratory procedures, demonstrations, and classroom activities/materials, including chi-square tests on a microcomputer, an integrated biology game, microscope slides of leaf stomata, culturing soil nematodes, technique for watering locust egg-laying tubes, hazards of biological chemicals (such as benzene, benzidene, calchicine,…

  4. Biology Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1982

    1982-01-01

    Describes laboratory procedures, demonstrations, and classroom activities/materials, including use of dwarf cichlids (fishes) in secondary school biology, teaching edge effects on stomatal diffusion, computer program on effects of selection on gene frequencies, biological oxidation/reduction reactions, short cuts with Drosophila, computer program…

  5. Biology Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1982

    1982-01-01

    Presents procedures, exercises, demonstrations, and information on a variety of biology topics including labeling systems, biological indicators of stream pollution, growth of lichens, reproductive capacity of bulbous buttercups, a straw balance to measure transpiration, interaction of fungi, osmosis, and nitrogen fixation and crop production. (DC)

  6. Biology Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1978

    1978-01-01

    Presents experiments, demonstrations, activities and ideas relating to various fields of biology to be used in biology courses in secondary schools. Among those experiments presented are demonstrating the early stages of ferns and mosses and simple culture methods for fern prothalli. (HM)

  7. Hyperbaric Oxygen Therapy

    MedlinePlus

    ... causes tissue death Nonhealing wounds, such as a diabetic foot ulcer Radiation injury Skin graft or skin flap ... hyperbaric oxygenation therapy in the management of chronic diabetic foot ulcers. Mayo Clinic Proceedings. 2013;88:166. Indications ...

  8. OXYGEN TRANSPORT CERAMIC MEMBRANES

    SciTech Connect

    Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

    2002-07-01

    In the present quarter, oxygen transport perovskite ceramic membranes are evaluated for strength and fracture in oxygen gradient conditions. Oxygen gradients are created in tubular membranes by insulating the inner surface from the reducing environment by platinum foils. Fracture in these test conditions is observed to have a gradient in trans and inter-granular fracture as opposed to pure trans-granular fracture observed in homogeneous conditions. Fracture gradients are reasoned to be due to oxygen gradient set up in the membrane, variation in stoichiometry across the thickness and due to varying decomposition of the parent perovskite. The studies are useful in predicting fracture criterion in actual reactor conditions and in understanding the initial evolution of fracture processes.

  9. Medical Oxygen Safety

    MedlinePlus

    ... injuries and deaths. from a heat source, open flames or electrical devices. KKK Body oil, hand lotion ... the oxygen. Post No Smoking and No Open Flames signs in and outside the home to remind ...

  10. High Selectivity Oxygen Delignification

    SciTech Connect

    Lucian A. Lucia

    2005-11-15

    Project Objective: The objectives of this project are as follows: (1) Examine the physical and chemical characteristics of a partner mill pre- and post-oxygen delignified pulp and compare them to lab generated oxygen delignified pulps; (2) Apply the chemical selectivity enhancement system to the partner pre-oxygen delignified pulps under mill conditions (with and without any predetermined amounts of carryover) to determine how efficiently viscosity is preserved, how well selectivity is enhanced, if strength is improved, measure any yield differences and/or bleachability differences; and (3) Initiate a mill scale oxygen delignification run using the selectivity enhancement agent, collect the mill data, analyze it, and propose any future plans for implementation.

  11. Dissolved oxygen: Chapter 6

    USGS Publications Warehouse

    Senn, David; Downing-Kunz, Maureen; Novick, Emily

    2016-01-01

    Dissolved oxygen (DO) concentration serves as an important indicator of estuarine habitat condition, because all aquatic macro-organisms require some minimum DO level to survive and prosper. The instantaneous DO concentration, measured at a specific location in the water column, results from a balance between multiple processes that add or remove oxygen (Figure 6.1): primary production produces O2; aerobic respiration in the water column and sediments consumes O2; abiotic or microbially-mediated biogeochemical reactions utilize O2 as an oxidant (e.g., oxidation of ammonium, sulfide, and ferrous iron); O2 exchange occurs across the air:water interface in response to under- or oversaturated DO concentrations in the water column; and water currents and turbulent mixing transport DO into and out of zones in the water column. If the oxygen loss rate exceeds the oxygen production or input rate, DO concentration decreases. When DO losses exceed production or input over a prolonged enough period of time, hypoxia ((<2-3 mg/L) or anoxia can develop. Persistent hypoxia or anoxia causes stress or death in aquatic organism populations, or for organisms that can escape a hypoxic or anoxic area, the loss of habitat. In addition, sulfide, which is toxic to aquatic organisms and causes odor problems, escapes from sediments under low oxygen conditions. Low dissolved oxygen is a common aquatic ecosystem response to elevated organic

  12. [Oxygen Leukocyte Larceny].

    PubMed

    Pinto da Costa, Miguel; Pimenta Coelho, Henrique

    2016-05-01

    The authors present a case of a 60-year-old male patient, previously diagnosed with B-cell chronic lymphocytic leukemia, who was admitted to the Emergency Room with dyspnea. The initial evaluation revealed severe anemia (Hgb = 5.0 g/dL) with hyperleukocytosis (800.000/µL), nearly all of the cells being mature lymphocytes, a normal chest X-ray and a low arterial oxygen saturation (89%; pulse oximetry). After red blood cell transfusion, Hgb values rose (9.0 g/dL) and there was a complete reversion of the dyspnea. Yet, subsequent arterial blood gas analysis, without the administration of supplemental oxygen, systematically revealed very low oxygen saturation values (~ 46%), which was inconsistent with the patientâs clinical state and his pulse oximetry values (~ 87%), and these values were not corrected by the administration of oxygen via non-rebreather mask. The investigation performed allowed to establish the diagnosis of oxygen leukocyte larceny, a phenomenon which conceals the true oxygen saturation due to peripheral consumption by leukocytes.

  13. Biological Oceanography

    NASA Astrophysics Data System (ADS)

    Dyhrman, Sonya

    2004-10-01

    The ocean is arguably the largest habitat on the planet, and it houses an astounding array of life, from microbes to whales. As a testament to this diversity and its importance, the discipline of biological oceanography spans studies of all levels of biological organization, from that of single genes, to organisms, to their population dynamics. Biological oceanography also includes studies on how organisms interact with, and contribute to, essential global processes. Students of biological oceanography are often as comfortable looking at satellite images as they are electron micrographs. This diversity of perspective begins the textbook Biological Oceanography, with cover graphics including a Coastal Zone Color Scanner image representing chlorophyll concentration, an electron micrograph of a dinoflagellate, and a photograph of a copepod. These images instantly capture the reader's attention and illustrate some of the different scales on which budding oceanographers are required to think. Having taught a core graduate course in biological oceanography for many years, Charlie Miller has used his lecture notes as the genesis for this book. The text covers the subject of biological oceanography in a manner that is targeted to introductory graduate students, but it would also be appropriate for advanced undergraduates.

  14. Measurement of oxygen transfer from air into organic solvents

    PubMed Central

    Ramesh, Hemalata; Hobisch, Mathias; Borisov, Sergey; Klimant, Ingo; Krühne, Ulrich; Woodley, John M

    2015-01-01

    Abstract BACKGROUND The use of non‐aqueous organic media is becoming increasingly important in many biotechnological applications in order to achieve process intensification. Such media can be used, for example, to directly extract poorly water‐soluble toxic products from fermentations. Likewise many biological reactions require the supply of oxygen, most normally from air. However, reliable online measurements of oxygen concentration in organic solvents (and hence oxygen transfer rates from air to the solvent) has to date proven impossible due to limitations in the current analytical methods. RESULTS For the first time, online oxygen measurements in non‐aqueous media using a novel optical sensor are demonstrated. The sensor was used to measure oxygen concentration in various organic solvents including toluene, THF, isooctane, DMF, heptane and hexane (which have all been shown suitable for several biological applications). Subsequently, the oxygen transfer rates from air into these organic solvents were measured. CONCLUSION The measurement of oxygen transfer rates from air into organic solvents using the dynamic method was established using the solvent resistant optical sensor. The feasibility of online oxygen measurements in organic solvents has also been demonstrated, paving the way for new opportunities in process control. © 2015 The Authors. Journal of Chemical Technology & Biotechnology published by JohnWiley & Sons Ltd on behalf of Society of Chemical Industry. PMID:27773958

  15. BIOLOGICAL WARFARE

    PubMed Central

    Beeston, John

    1953-01-01

    The use of biological agents as controlled weapons of war is practical although uncertain. Three types of agents are feasible, including pathogenic organisms and biological pests, toxins, and synthetic hormones regulating plant growth. These agents may be chosen for selective effects varying from prolonged incipient illness to death of plants, man and domestic animals. For specific preventive and control measures required to combat these situations, there must be careful and detailed planning. The nucleus of such a program is available within the existing framework of public health activities. Additional research and expansion of established activities in time of attack are necessary parts of biological warfare defense. PMID:13059641

  16. Foldit Biology

    DTIC Science & Technology

    2015-07-31

    Report 8/1/2013-7/31/2015 4. TITLE AND SUBTITLE Sa. CONTRACT NUMBER Foldit Biology NOOO 14-13-C-0221 Sb. GRANT NUMBER N/A Sc. PROGRAM ELEMENT...Include area code) Unclassified Unclassified Unclassified (206) 616-2660 Zoran Popović Foldit Biology (Task 1, 2, 3, 4) Final Report...Period Covered by the Report August 1, 2013 – July 31, 2015 Date of Report: July 31, 2015 Project Title: Foldit Biology Contract Number: N00014-13

  17. Steroids, triterpenoids and molecular oxygen

    PubMed Central

    Summons, Roger E; Bradley, Alexander S; Jahnke, Linda L; Waldbauer, Jacob R

    2006-01-01

    There is a close connection between modern-day biosynthesis of particular triterpenoid biomarkers and presence of molecular oxygen in the environment. Thus, the detection of steroid and triterpenoid hydrocarbons far back in Earth history has been used to infer the antiquity of oxygenic photosynthesis. This prompts the question: were these compounds produced similarly in the past? In this paper, we address this question with a review of the current state of knowledge surrounding the oxygen requirement for steroid biosynthesis and phylogenetic patterns in the distribution of steroid and triterpenoid biosynthetic pathways. The hopanoid and steroid biosynthetic pathways are very highly conserved within the bacterial and eukaryotic domains, respectively. Bacteriohopanepolyols are produced by a wide range of bacteria, and are methylated in significant abundance at the C2 position by oxygen-producing cyanobacteria. On the other hand, sterol biosynthesis is sparsely distributed in distantly related bacterial taxa and the pathways do not produce the wide range of products that characterize eukaryotes. In particular, evidence for sterol biosynthesis by cyanobacteria appears flawed. Our experiments show that cyanobacterial cultures are easily contaminated by sterol-producing rust fungi, which can be eliminated by treatment with cycloheximide affording sterol-free samples. Sterols are ubiquitous features of eukaryotic membranes, and it appears likely that the initial steps in sterol biosynthesis were present in their modern form in the last common ancestor of eukaryotes. Eleven molecules of O2 are required by four enzymes to produce one molecule of cholesterol. Thermodynamic arguments, optimization of function and parsimony all indicate that an ancestral anaerobic pathway is highly unlikely. The known geological record of molecular fossils, especially steranes and triterpanes, is notable for the limited number of structural motifs that have been observed. With a few exceptions

  18. Biological monitoring

    SciTech Connect

    Ho, M.H.; Dillon, H.K.

    1986-02-01

    Biological monitoring is defined as the measurement and assessment of workplace agents or their metabolites in tissues, secreta, excreta, expired air, or any combination of these to evaluate exposure and health risk compared to an appropriate reference. Biological monitoring offers several advantages: it takes into account individual variability in biological activity resulting from a chemical insult. It takes into account the effects of personal physical activity and individual life styles. It is a valuable adjunct to ambient monitoring and health surveillance. The importance of chemical speciation in the toxicity of pollutants is discussed. Basic protocols for lead, aluminum, cadmium, mercury, selenium, and nickel are presented. Basic criteria for biological monitoring methods are presented. 11 references, 1 table.

  19. Bottle Biology.

    ERIC Educational Resources Information Center

    CSTA Journal, 1995

    1995-01-01

    Provides hands-on biology activities using plastic bottles that allow students to become engaged in asking questions, creating experiments, testing hypotheses, and generating answers. Activities explore terrestrial and aquatic systems. (MKR)

  20. Biology Notes

    ERIC Educational Resources Information Center

    School Science Review, 1972

    1972-01-01

    Ten ideas that have been tried out by the authors in schools are presented for biology teachers. The areas covered include genetics, dispersal of seeds, habituation in earthworms, respiration, sensory neurons, fats and oils. A reading list is provided. (PS)

  1. Biology Notes

    ERIC Educational Resources Information Center

    School Science Review, 1972

    1972-01-01

    Twelve new experiments in biology are described by teachers for use in classrooms. Broad areas covered include enzyme action, growth regulation, microscopy, respiration, germination, plant succession, leaf structure and blood structure. Explanations are detailed. (PS)

  2. Biology Notes

    ERIC Educational Resources Information Center

    School Science Review, 1973

    1973-01-01

    Some helpful ideas are proposed for use by biology teachers. Topics included are Food Webs,'' Key to Identification of Families,'' Viruses,'' Sieve Tube,'' Woodlice,'' Ecology of Oak Leaf Roller Moth,'' and Model Making.'' (PS)

  3. Venous oxygen saturation.

    PubMed

    Hartog, Christiane; Bloos, Frank

    2014-12-01

    Early detection and rapid treatment of tissue hypoxia are important goals. Venous oxygen saturation is an indirect index of global oxygen supply-to-demand ratio. Central venous oxygen saturation (ScvO2) measurement has become a surrogate for mixed venous oxygen saturation (SvO2). ScvO2 is measured by a catheter placed in the superior vena cava. After results from a single-center study suggested that maintaining ScvO2 values >70% might improve survival rates in septic patients, international practice guidelines included this target in a bundle strategy to treat early sepsis. However, a recent multicenter study with >1500 patients found that the use of central hemodynamic and ScvO2 monitoring did not improve long-term survival when compared to the clinical assessment of the adequacy of circulation. It seems that if sepsis is recognized early, a rapid initiation of antibiotics and adequate fluid resuscitation are more important than measuring venous oxygen saturation.

  4. Optical oxygen concentration monitor

    DOEpatents

    Kebabian, P.

    1997-07-22

    A system for measuring and monitoring the concentration of oxygen uses as a light source an argon discharge lamp, which inherently emits light with a spectral line that is close to one of oxygen`s A-band absorption lines. In a preferred embodiment, the argon line is split into sets of components of shorter and longer wavelengths by a magnetic field of approximately 2,000 Gauss that is parallel to the light propagation from the lamp. The longer wavelength components are centered on an absorption line of oxygen and thus readily absorbed, and the shorter wavelength components are moved away from that line and minimally absorbed. A polarization modulator alternately selects the set of the longer wavelength, or upshifted, components or the set of the shorter wavelength, or downshifted, components and passes the selected set to an environment of interest. After transmission over a path through that environment, the transmitted optical flux of the argon line varies as a result of the differential absorption. The system then determines the concentration of oxygen in the environment based on the changes in the transmitted optical flux between the two sets of components. In alternative embodiments modulation is achieved by selectively reversing the polarity of the magnetic field or by selectively supplying the magnetic field to either the emitting plasma of the lamp or the environment of interest. 4 figs.

  5. Atomic oxygen stimulated outgassing

    NASA Technical Reports Server (NTRS)

    Linton, Roger C.; Reynolds, John M.

    1991-01-01

    The passive Long Duration Exposure Facility (LDEF) Experiment A0034, Atomic Oxygen Simulated Outgassing, consisted of two identical one-sixth tray modules, exposing selected thermal control coatings to atomic oxygen and the combined space environment on the leading edge and, for reference, to the relative wake environment on the trailing edge. Optical mirrors were included adjacent to the thermal coatings for deposition of outgassing products. Ultraviolet grade windows and metal covers were provided for additional assessment of the effects of the various environmental factors. Preliminary results indicate that orbital atomic oxygen is both a degrading and a optically restorative factor in the thermo-optical properties of selected thermal coatings. There is evidence of more severe optical degradation on collector mirrors adjacent to coatings that were exposed to the RAM-impinging atomic oxygen. This evidence of atomic oxygen stimulated outgassing is discussed in relation to alternative factors that could affect degradation. The general effects of the space environment on the experiment hardware as well as the specimens are discussed.

  6. 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

  7. Monolithic solid electrolyte oxygen pump

    DOEpatents

    Fee, Darrell C.; Poeppel, Roger B.; Easler, Timothy E.; Dees, Dennis W.

    1989-01-01

    A multi-layer oxygen pump having a one-piece, monolithic ceramic structure affords high oxygen production per unit weight and volume and is thus particularly adapted for use as a portable oxygen supply. The oxygen pump is comprised of a large number of small cells on the order of 1-2 millimeters in diameter which form the walls of the pump and which are comprised of thin, i.e., 25-50 micrometers, ceramic layers of cell components. The cell components include an air electrode, an oxygen electrode, an electrolyte and interconnection materials. The cell walls form the passages for input air and for exhausting the oxygen which is transferred from a relatively dilute gaseous mixture to a higher concentration by applying a DC voltage across the electrodes so as to ionize the oxygen at the air electrode, whereupon the ionized oxygen travels through the electrolyte and is converted to oxygen gas at the oxygen electrode.

  8. Novel nanostructured oxygen sensor

    NASA Astrophysics Data System (ADS)

    Boardman, Alan James

    New government regulations and industry requirements for medical oxygen sensors require the development of alternate materials and process optimization of primary sensor components. Current oxygen sensors are not compliant with the Restriction of Hazardous Substances (RoHS) Directive. This work focused on two areas. First, was finding suitable readily available materials for the sensor anodes. Second was optimizing the processing of the sensor cathode membrane for reduced delamination. Oxygen sensors were made using tin (Sn) and bismuth (Bi) electrodes, potassium hydroxide (KOH) and acetic acid (CH3COOH) electrolytes with platinum (Pt) and gold (Au) reference electrodes. Bi electrodes were fabricated by casting and pressing processes. Electrochemical characterization of the Sn and Bi electrodes was performed by Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS) and sensing characterization per BSEN ISO 21647:2009 at various oxygen percentages, 0%, 20.9% and 100% oxygen levels with an automated test apparatus. The Sn anode with both electrolyte solutions showed good oxygen sensing properties and performance in a sensor. This system shows promise for replacement of Pb electrodes as required by the RoHS Directive. The Bi anode with Au cathode in both KOH and CH3COOH electrolytes showed acceptable performance and oxygen sensing properties. The Bi anodes fabricated by separate manufacturing methods demonstrated effectiveness for use in medical oxygen sensors. Gold thin films were prepared by magnetron sputtering on Flouroethylene Polymer (FEP) films. The FEP substrate temperature ranged from -77°C to 50°C. X-Ray Diffraction (XRD) and 4-point resistivity characterized the effects of substrate temperature to Au thin film particle size. XRD peak broadening and resistivity measurements showed a strong correlation of particle size to FEP substrate temperature. Particle size at 50°C was 594A and the -77°C particle size was 2.4 x 103A. Substrate

  9. Neurological oxygen toxicity.

    PubMed

    Farmery, Scott; Sykes, Oliver

    2012-10-01

    SCUBA diving has several risks associated with it from breathing air under pressure--nitrogen narcosis, barotrauma and decompression sickness (the bends). Trimix SCUBA diving involves regulating mixtures of nitrogen, oxygen and helium in an attempt to overcome the risks of narcosis and decompression sickness during deep dives, but introduces other potential hazards such as hypoxia and oxygen toxicity convulsions. This study reports on a seizure during the ascent phase, its potential causes and management and discusses the hazards posed to the diver and his rescuer by an emergency ascent to the surface.

  10. Mapping tissue oxygen in vivo by photoacoustic lifetime imaging

    NASA Astrophysics Data System (ADS)

    Shao, Qi; Morgounova, Ekaterina; Choi, Jeung-Hwan; Jiang, Chunlan; Bischof, John; Ashkenazi, Shai

    2013-03-01

    Oxygen plays a key role in the energy metabolism of living organisms. Any imbalance in the oxygen levels will affect the metabolic homeostasis and lead to pathophysiological diseases. Hypoxia, a status of low tissue oxygen, is a key factor in tumor biology as it is highly prominent in tumor tissues. However, clinical tools for assessing tissue oxygenation are limited. The gold standard is polarographic needle electrode which is invasive and not capable of mapping (imaging) the oxygen content in tissue. We applied the method of photoacoustic lifetime imaging (PALI) of oxygen-sensitive dye to small animal tissue hypoxia research. PALI is new technology for direct, non-invasive imaging of oxygen. The technique is based on mapping the oxygen-dependent transient optical absorption of Methylene Blue (MB) by pump-probe photoacoustic imaging. Our studies show the feasibility of imaging of dissolved oxygen distribution in phantoms. In vivo experiments demonstrate that the hypoxia region is consistent with the site of subcutaneously xenografted prostate tumor in mice with adequate spatial resolution and penetration depth.

  11. THE PRODUCTION OF HYDROGEN PEROXIDE BY HIGH OXYGEN PRESSURES

    PubMed Central

    Gilbert, Daniel L.; Gerschman, Rebeca; Ruhm, K. Barclay; Price, William E.

    1958-01-01

    Hydrogen peroxide is formed in solutions of glutathione exposed to oxygen. This hydrogen peroxide or its precursors will decrease the viscosity of polymers like desoxyribonucleic acid and sodium alginate. Further knowledge of the mechanism of these chemical effects of oxygen might further the understanding of the biological effects of oxygen. This study deals with the rate of solution of oxygen and with the decomposition of hydrogen peroxide in chemical systems exposed to high oxygen pressures. At 6 atmospheres, the absorption coefficient for oxygen into water was about 1 cm./hour and at 143 atmospheres, it was about 2 cm./hour; the difference probably being due to the modus operandi. The addition of cobalt (II), manganese (II), nickel (II), or zinc ions in glutathione (GSH) solutions exposed to high oxygen pressure decreased the net formation of hydrogen peroxide and also the reduced glutathione remaining in the solution. Studies on hydrogen peroxide decomposition indicated that these ions act probably by accelerating the hydrogen perioxide oxidation of glutathione. The chelating agent, ethylenediaminetetraacetic acid disodium salt, inhibited the oxidation of GSH exposed to high oxygen pressure for 14 hours. However, indication that oxidation still occurred, though at a much slower rate, was found in experiments lasting 10 weeks. Thiourea decomposed hydrogen peroxide very rapidly. When GSH solutions were exposed to high oxygen pressure, there was oxidation of the GSH, which became relatively smaller with increasing concentrations of GSH. PMID:13525677

  12. Water induced dismutation of superoxide anion generates singlet molecular oxygen.

    PubMed

    Corey, E J; Mehrotra, M M; Khan, A U

    1987-06-15

    Direct spectroscopic measurement of 1268 nm singlet oxygen emission from KO2 suspensions at room temperature in three non-protonic solvents--CCl4, Cl2FCCClF2, and C6F14 by the action of water is reported. The results clearly show that the singlet oxygen generation is due to a water induced reaction, and suggest that one role of the enzyme superoxide dismutase may be the protection of biological structures, for example, lipid membranes, from degradation by singlet oxygen.

  13. The Solubility of Oxygen and Ozone in Liquids

    NASA Astrophysics Data System (ADS)

    Battino, Rubin; Rettich, Timothy R.; Tominaga, Toshihiro

    1983-04-01

    This review covers the solubility of oxygen and ozone in liquids as a function of temperature and pressure. Solubility data for individual systems were critically evaluated and recommended or tentative values presented in many cases. The trend of solubilities in homologous series or related solvents is discussed. Liquids include water; seawater; aqueous salt solutions; mixed solvents; hydrocarbons; organic compounds containing oxygen, halogen, sulfur, nitrogen, or silicon; olive oil; and human blood. For ozone, only its solubility in water is presented. Key words: aqueous solutions; biological fluids; gas solubility; hydrocarbons; mixed solvents; organic solvents; oxygen; ozone; seawater; water.

  14. Biological Oceanography

    NASA Technical Reports Server (NTRS)

    Abbott, M. R.

    1984-01-01

    Within the framework of global biogeochemical cycles and ocean productivity, there are two areas that will be of particular interest to biological oceanography in the 1990s. The first is the mapping in space time of the biomass and productivity of phytoplankton in the world ocean. The second area is the coupling of biological and physical processes as it affects the distribution and growth rate of phytoplankton biomass. Certainly other areas will be of interest to biological oceanographers, but these two areas are amenable to observations from satellites. Temporal and spatial variability is a regular feature of marine ecosystems. The temporal and spatial variability of phytoplankton biomass and productivity which is ubiquitous at all time and space scales in the ocean must be characterized. Remote sensing from satellites addresses these problems with global observations of mesocale (2 to 20 days, 10 to 200 km) features over a long period of time.

  15. Biological preconcentrator

    DOEpatents

    Manginell, Ronald P.; Bunker, Bruce C.; Huber, Dale L.

    2008-09-09

    A biological preconcentrator comprises a stimulus-responsive active film on a stimulus-producing microfabricated platform. The active film can comprise a thermally switchable polymer film that can be used to selectively absorb and desorb proteins from a protein mixture. The biological microfabricated platform can comprise a thin membrane suspended on a substrate with an integral resistive heater and/or thermoelectric cooler for thermal switching of the active polymer film disposed on the membrane. The active polymer film can comprise hydrogel-like polymers, such as poly(ethylene oxide) or poly(n-isopropylacrylamide), that are tethered to the membrane. The biological preconcentrator can be fabricated with semiconductor materials and technologies.

  16. Oxygen isotope fractionation of dissolved oxygen during reduction by ferrous iron

    NASA Astrophysics Data System (ADS)

    Oba, Yasuhiro; Poulson, Simon R.

    2009-01-01

    The oxygen isotope fractionation factor of dissolved oxygen gas has been measured during inorganic reduction by aqueous FeSO 4 at 10-54 °C under neutral (pH 7) and acidic (pH 2) conditions, with Fe(II) concentrations ranging up to 0.67 mol L -1, in order to better understand the geochemical behavior of oxygen in ferrous iron-rich groundwater and acidic mine pit lakes. The rate of oxygen reduction increased with increasing temperature and increasing Fe(II) concentration, with the pseudo-first-order rate constant k ranging from 2.3 to 82.9 × 10 -6 s -1 under neutral conditions and 2.1 to 37.4 × 10 -7 s -1 under acidic conditions. The activation energy of oxygen reduction was 30.9 ± 6.6 kJ mol -1 and 49.7 ± 13.0 kJ mol -1 under neutral and acidic conditions, respectively. Oxygen isotope enrichment factors ( ɛ) become smaller with increasing temperature, increasing ferrous iron concentration, and increasing reaction rate under acidic conditions, with ɛ values ranging from -4.5‰ to -11.6‰. Under neutral conditions, ɛ does not show any systematic trends vs. temperature or ferrous iron concentration, with ɛ values ranging from -7.3 to -10.3‰. Characterization of the oxygen isotope fractionation factor associated with O 2 reduction by Fe(II) will have application to elucidating the process or processes responsible for oxygen consumption in environments such as groundwater and acidic mine pit lakes, where a number of possible processes (e.g. biological respiration, reduction by reduced species) may have taken place.

  17. Doping with artificial oxygen carriers: an update.

    PubMed

    Schumacher, Yorck Olaf; Ashenden, Michael

    2004-01-01

    There is a long history of science seeking to develop artificial substitutes for body parts damaged by disease or trauma. While defective teeth and limbs are commonly replaced by imitations without major loss of functionality, the development of a substitute for red blood cells has proved elusive. There is a permanent shortage of donor blood in western societies. Nevertheless, despite whole blood transfusions carrying measurable risks due to immunogenicity and the transmission of blood-borne infectious diseases, red blood cells are still relatively inexpensive, well tolerated and widely available. Researchers seeking to develop products that are able to meet and perhaps exceed these criteria have responded to this difficult challenge by adopting many different approaches. Work has focussed on two classes of substances: modified haemoglobin solutions and perfluorocarbon emulsions. Other approaches include the creation of artificial red cells, where haemoglobin and supporting enzyme systems are encapsulated into liposomes. Haemoglobin is ideally suited to oxygen transport when encased by the red cell membrane; however, once removed, it rapidly dissociates into dimers and is cleared by the kidney. Therefore, it must be stabilised before it can be safely re-infused into humans. Modifications concomitantly alter the vascular half-life, oxygen affinity and hypertensive characteristics of raw haemoglobin, which can be sourced from outdated blood stores, genetically-engineered Escherichia coli or even bovine herds. In contrast, perfluorocarbons are entirely synthetic molecules that are capable of dissolving oxygen but biologically inert. Since they dissolve rather than bind oxygen, their capacity to serve as a blood substitute is determined principally by the oxygen pressure gradients in the lung and at the target tissue. Blood substitutes have important potential areas of clinical application including red cell replacement during surgery, emergency resuscitation of

  18. Two-photon absorbing porphyrins for oxygen microscopy (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Esipova, Tatiana V.; Vinogradov, Sergei A.

    2016-03-01

    The ability to quantify oxygen in vivo in 3D with high spatial and temporal resolution is invaluable for many areas of the biomedical science, including ophthalmology, neuroscience, cancer and stem biology. An optical method based on oxygen-dependent quenching of phosphorescence is being developed, that allows quantitative minimally invasive real-time imaging of partial pressure of oxygen (pO2) in tissue. In the past, dendritically protected phosphorescent oxygen probes with controllable quenching parameters and defined bio-distributions have been developed. More recently our probe strategy has extended to encompass two-photon excitable oxygen probes, which brought about first demonstrations of two-photon phosphorescence lifetime microscopy (2PLM) of oxygen in vivo, providing new valuable information for neuroscience and stem cell biology. However, current two-photon oxygen probes suffer from a number of limitations, such as low brightness and high cost of synthesis, which dramatically reduce imaging performance and limit usability of the method. Here we present an approach to new bright phosphorescent chromophores with internally enhanced two-photon absorption cross-sections, which pave a way to novel proves for 2PLM. In addition to substantial increase in performance, the new probes can be synthesized by much more efficient methods, thereby greatly reducing the cost of the synthesis and making the technique accessible to a broader range of researchers across different fields.

  19. (Biological dosimetry)

    SciTech Connect

    Sega, G.A.

    1990-11-06

    The traveler participated in an International Symposium on Trends in Biological Dosimetry and presented an invited paper entitled, Adducts in sperm protamine and DNA vs mutation frequency.'' The purpose of the Symposium was to examine the applicability of new methods to study quantitatively the effects of xenobiotic agents (radiation and chemicals) on molecular, cellular and organ systems, with special emphasis on human biological dosimetry. The general areas covered at the meeting included studies on parent compounds and metabolites; protein adducts; DNA adducts; gene mutations; cytogenetic end-points and reproductive methods.

  20. Benzoylation of Ergosterol through Nucleophilic Acyl Substitution and Subsequent Formation of Ergosterol Benzoate Endoperoxide by Reaction with Singlet Oxygen Generated by Photosensitization

    ERIC Educational Resources Information Center

    Roslaniec, Mary C.; Sanford, Elizabeth M.

    2011-01-01

    Reactive oxygen species such as singlet oxygen have been a major focus of research in medicine. The effect of singlet oxygen on sterols within biological membranes is becoming increasingly more important. Ergosterol, a vitamin D precursor, is one such sterol. The benzoylation of ergosterol and subsequent reaction with singlet oxygen to form an…

  1. The Oxygen Cycle.

    ERIC Educational Resources Information Center

    Swant, Gary D.

    Produced for primary grades, this booklet provides study of the oxygen-carbon dioxide cycle in nature. Line drawings, a minimum amount of narrative, and a glossary of terms make up its content. The booklet is designed to be used as reading material, a coloring book, or for dramatic arts with students acting out parts of the cycle. This work was…

  2. OXYGEN TRANSPORT CERAMIC MEMBRANES

    SciTech Connect

    Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

    2003-01-01

    In the present quarter, the possibility of using a more complex interfacial engineering approach to the development of reliable and stable oxygen transport perovskite ceramic membranes/metal seals is discussed. Experiments are presented and ceramic/metal interactions are characterized. Crack growth and fracture toughness of the membrane in the reducing conditions are also discussed. Future work regarding this approach is proposed are evaluated for strength and fracture in oxygen gradient conditions. Oxygen gradients are created in tubular membranes by insulating the inner surface from the reducing environment by platinum foils. Fracture in these test conditions is observed to have a gradient in trans and inter-granular fracture as opposed to pure trans-granular fracture observed in homogeneous conditions. Fracture gradients are reasoned to be due to oxygen gradient set up in the membrane, variation in stoichiometry across the thickness and due to varying decomposition of the parent perovskite. The studies are useful in predicting fracture criterion in actual reactor conditions and in understanding the initial evolution of fracture processes.

  3. The Oxygen Flask Method

    ERIC Educational Resources Information Center

    Boulton, L. H.

    1973-01-01

    Discusses application of Schoniger's method of quantitative organic elemental analysis in teaching of qualitative analysis of the halogens, nitrogen, sulphur, and phosphorus. Indicates that the oxygen flask method is safe and suitable for both high school and college courses because of simple apparatus requirements. (CC)

  4. Optical oxygen concentration monitor

    DOEpatents

    Kebabian, Paul

    1997-01-01

    A system for measuring and monitoring the concentration of oxygen uses as a light source an argon discharge lamp, which inherently emits light with a spectral line that is close to one of oxygen's A-band absorption lines. In a preferred embodiment, the argon line is split into sets of components of shorter and longer wavelengths by a magnetic field of approximately 2000 Gauss that is parallel to the light propagation from the lamp. The longer wavelength components are centered on an absorption line of oxygen and thus readily absorbed, and the shorter wavelength components are moved away from that line and minimally absorbed. A polarization modulator alternately selects the set of the longer wavelength, or upshifted, components or the set of the shorter wavelength, or downshifted, components and passes the selected set to an environment of interest. After transmission over a path through that environment, the transmitted optical flux of the argon line varies as a result of the differential absorption. The system then determines the concentration of oxygen in the environment based on the changes in the transmitted optical flux between the two sets of components. In alternative embodiments modulation is achieved by selectively reversing the polarity of the magnetic field or by selectively supplying the magnetic field to either the emitting plasma of the lamp or the environment of interest.

  5. Atomic Oxygen Task

    NASA Technical Reports Server (NTRS)

    Hadaway, James B.

    1997-01-01

    This report details work performed by the Center for Applied Optics (CAO) at the University of Alabama in Huntsville (UAH) on the contract entitled 'Atomic Oxygen Task' for NASA's Marshall Space Flight Center (contract NAS8-38609, Delivery Order 109, modification number 1). Atomic oxygen effects on exposed materials remain a critical concern in designing spacecraft to withstand exposure in the Low Earth Orbit (LEO) environment. The basic objective of atomic oxygen research in NASA's Materials & Processes (M&P) Laboratory is to provide the solutions to material problems facing present and future space missions. The objective of this work was to provide the necessary research for the design of specialized experimental test configurations and development of techniques for evaluating in-situ space environmental effects, including the effects of atomic oxygen and electromagnetic radiation on candidate materials. Specific tasks were performed to address materials issues concerning accelerated environmental testing as well as specifically addressing materials issues of particular concern for LDEF analysis and Space Station materials selection.

  6. Hybrid Oxygen System

    DTIC Science & Technology

    1992-10-01

    otherwise in any manner construed, as licensing the holder or any other person or corporation ; or as conveying any rights or permission to manufacture, use...12 Modest Activity 2 12 24 Comnat ane G’s Average 5 32 64 Peak Activity (NATO) 10 50 Instantaneous Peak Flow N/A 150-20W_ Published oxygen flow rates

  7. Oxygen Extraction from Minerals

    NASA Technical Reports Server (NTRS)

    Muscatello, Tony

    2017-01-01

    Oxygen, whether used as part of rocket bipropellant or for astronaut life support, is a key consumable for space exploration and commercialization. In Situ Resource Utilization (ISRU) has been proposed many times as a method for making space exploration more cost effective and sustainable. On planetary and asteroid surfaces the presence of minerals in the regolith that contain oxygen is very common, making them a potential oxygen resource. The majority of research and development for oxygen extraction from minerals has been for lunar regolith although this work would generally be applicable to regolith at other locations in space. This presentation will briefly survey the major methods investigated for oxygen extraction from regolith with a focus on the current status of those methods and possible future development pathways. The major oxygen production methods are (1) extraction from lunar ilmenite (FeTiO3) with either hydrogen or carbon monoxide, (2) carbothermal reduction of iron oxides and silicates with methane, and (3) molten regolith electrolysis (MRE) of silicates. Methods (1) and (2) have also been investigated in a two-step process using CO reduction and carbon deposition followed by carbothermal reduction. All three processes have byproducts that could also be used as resources. Hydrogen or carbon monoxide reduction produce iron metal in small amounts that could potentially be used as construction material. Carbothermal reduction also makes iron metal along with silicon metal and a glass with possible applications. MRE produces iron, silicon, aluminum, titanium, and glass, with higher silicon yields than carbothermal reduction. On Mars and possibly on some moons and asteroids, water is present in the form of mineral hydrates, hydroxyl (-OH) groups on minerals, andor water adsorbed on mineral surfaces. Heating of the minerals can liberate the water which can be electrolyzed to provide a source of oxygen as well. The chemistry of these processes, some key

  8. Biology Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1981

    1981-01-01

    Presents content information and/or laboratory procedures and experiments on different biology topics including small-scale cultivation of watercress and its use in water-culture experiments, microbiology of the phylloplane, use of mouthbrooders in science class, and the gene. (DC)

  9. Marine Biology

    ERIC Educational Resources Information Center

    Dewees, Christopher M.; Hooper, Jon K.

    1976-01-01

    A variety of informational material for a course in marine biology or oceanology at the secondary level is presented. Among the topics discussed are: food webs and pyramids, planktonic blooms, marine life, plankton nets, food chains, phytoplankton, zooplankton, larval plankton and filter feeders. (BT)

  10. Biology Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1983

    1983-01-01

    Describes laboratory procedures, demonstrations, and classroom activities/materials, including water relation exercise on auxin-treated artichoke tuber tissue; aerobic respiration in yeast; an improved potometer; use of mobiles in biological classification, and experiments on powdery mildews and banana polyphenol oxidase. Includes reading lists…

  11. Cancer Biology

    ERIC Educational Resources Information Center

    Dominiecki, Mary E.

    2004-01-01

    University of Colorado's Virtual Student Fellowship available at and developed by Bakemeier, Richard F. This website is designed to give students applying for a fellowship an overview of basic topics in biology and how they are used by cancer researchers to develop new treatments.

  12. (Biological dosimetry)

    SciTech Connect

    Preston, R.J.

    1990-12-17

    The traveler attended the 1st International Conference on Biological Dosimetry in Madrid, Spain. This conference was organized to provide information to a general audience of biologists, physicists, radiotherapists, industrial hygiene personnel and individuals from related fields on the current ability of cytogenetic analysis to provide estimates of radiation dose in cases of occupational or environmental exposure. There is a growing interest in Spain in biological dosimetry because of the increased use of radiation sources for medical and occupational uses, and with this the anticipated and actual increase in numbers of overexposure. The traveler delivered the introductory lecture on Biological Dosimetry: Mechanistic Concepts'' that was intended to provide a framework by which the more applied lectures could be interpreted in a mechanistic way. A second component of the trip was to provide advice with regard to several recent cases of overexposure that had been or were being assessed by the Radiopathology and Radiotherapy Department of the Hospital General Gregorio Maranon'' in Madrid. The traveler had provided information on several of these, and had analyzed cells from some exposed or purportedly exposed individuals. The members of the biological dosimetry group were referred to individuals at REACTS at Oak Ridge Associated Universities for advice on follow-up treatment.

  13. Bottle Biology.

    ERIC Educational Resources Information Center

    Jager, Peter

    1993-01-01

    Describes activities which utilize plastic drink bottles and are designed to foster the development of a wide range of biological and ecological concepts. Includes instructions for making a model compost column and presents a model that illustrates open versus closed ecosystems. (DDR)

  14. Biology Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1980

    1980-01-01

    Describes equipment, activities, and experiments useful in biology and environmental education instruction, including, among others, sampling in ecology using an overhead projector, the slide finder as an aid to microscopy, teaching kidney function, and teaching wildlife conservation-sand dune systems. (SK)

  15. Scaffolded biology.

    PubMed

    Minelli, Alessandro

    2016-09-01

    Descriptions and interpretations of the natural world are dominated by dichotomies such as organism vs. environment, nature vs. nurture, genetic vs. epigenetic, but in the last couple of decades strong dissatisfaction with those partitions has been repeatedly voiced and a number of alternative perspectives have been suggested, from perspectives such as Dawkins' extended phenotype, Turner's extended organism, Oyama's Developmental Systems Theory and Odling-Smee's niche construction theory. Last in time is the description of biological phenomena in terms of hybrids between an organism (scaffolded system) and a living or non-living scaffold, forming unit systems to study processes such as reproduction and development. As scaffold, eventually, we can define any resource used by the biological system, especially in development and reproduction, without incorporating it as happens in the case of resources fueling metabolism. Addressing biological systems as functionally scaffolded systems may help pointing to functional relationships that can impart temporal marking to the developmental process and thus explain its irreversibility; revisiting the boundary between development and metabolism and also regeneration phenomena, by suggesting a conceptual framework within which to investigate phenomena of regular hypermorphic regeneration such as characteristic of deer antlers; fixing a periodization of development in terms of the times at which a scaffolding relationship begins or is terminated; and promoting plant galls to legitimate study objects of developmental biology.

  16. Biology Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1984

    1984-01-01

    Presents information on the teaching of nutrition (including new information relating to many current O-level syllabi) and part 16 of a reading list for A- and S-level biology. Also includes a note on using earthworms as a source of material for teaching meiosis. (JN)

  17. Biology Excursions

    ERIC Educational Resources Information Center

    Baldock, R. N.

    1973-01-01

    Provides many useful suggestions and cautions for planning and executing a biology field excursion. Specific procedures are outlined for investigating land communities and coastal areas, and a number of follow-up laboratory activities are described. The appendix provides an extensive bibliography with useful comments on the literature. (JR)

  18. Biology Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1979

    1979-01-01

    Organized by topic is a reading list for A- and S-level biology. Described are experiments for measuring rate of water uptake in a shoot; questions to aid students in designing experiments; rise of overhead projection to demonstrate osmosis and blood cell counting; and microbial manufacture of vinegar. (CS)

  19. Biology Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1981

    1981-01-01

    Outlines a variety of laboratory procedures, techniques, and materials including construction of a survey frame for field biology, a simple tidal system, isolation and applications of plant protoplasts, tropisms, teaching lung structure, and a key to statistical methods for biologists. (DS)

  20. Remediation of a winery wastewater combining aerobic biological oxidation and electrochemical advanced oxidation processes.

    PubMed

    Moreira, Francisca C; Boaventura, Rui A R; Brillas, Enric; Vilar, Vítor J P

    2015-05-15

    Apart from a high biodegradable fraction consisting of organic acids, sugars and alcohols, winery wastewaters exhibit a recalcitrant fraction containing high-molecular-weight compounds as polyphenols, tannins and lignins. In this context, a winery wastewater was firstly subjected to a biological oxidation to mineralize the biodegradable fraction and afterwards an electrochemical advanced oxidation process (EAOP) was applied in order to mineralize the refractory molecules or transform them into simpler ones that can be further biodegraded. The biological oxidation led to above 97% removals of dissolved organic carbon (DOC), chemical oxygen demand (COD) and 5-day biochemical oxygen demand (BOD5), but was inefficient on the degradation of a bioresistant fraction corresponding to 130 mg L(-1) of DOC, 380 mg O2 L(-1) of COD and 8.2 mg caffeic acid equivalent L(-1) of total dissolved polyphenols. Various EAOPs such as anodic oxidation with electrogenerated H2O2 (AO-H2O2), electro-Fenton (EF), UVA photoelectro-Fenton (PEF) and solar PEF (SPEF) were then applied to the recalcitrant effluent fraction using a 2.2 L lab-scale flow plant containing an electrochemical cell equipped with a boron-doped diamond (BDD) anode and a carbon-PTFE air-diffusion cathode and coupled to a photoreactor with compound parabolic collectors (CPCs). The influence of initial Fe(2+) concentration and current density on the PEF process was evaluated. The relative oxidative ability of EAOPs increased in the order AO-H2O2 < EF < PEF ≤ SPEF. The SPEF process using an initial Fe(2+) concentration of 35 mg L(-1), current density of 25 mA cm(-2), pH of 2.8 and 25 °C reached removals of 86% on DOC and 68% on COD after 240 min, regarding the biologically treated effluent, along with energy consumptions of 45 kWh (kg DOC)(-1) and 5.1 kWh m(-3). After this coupled treatment, color, odor, COD, BOD5, NH4(+), NO3(-) and SO4(2-) parameters complied with the legislation targets and, in addition, a total

  1. Integrative biology of exercise.

    PubMed

    Hawley, John A; Hargreaves, Mark; Joyner, Michael J; Zierath, Juleen R

    2014-11-06

    Exercise represents a major challenge to whole-body homeostasis provoking widespread perturbations in numerous cells, tissues, and organs that are caused by or are a response to the increased metabolic activity of contracting skeletal muscles. To meet this challenge, multiple integrated and often redundant responses operate to blunt the homeostatic threats generated by exercise-induced increases in muscle energy and oxygen demand. The application of molecular techniques to exercise biology has provided greater understanding of the multiplicity and complexity of cellular networks involved in exercise responses, and recent discoveries offer perspectives on the mechanisms by which muscle "communicates" with other organs and mediates the beneficial effects of exercise on health and performance.

  2. Biological satellite scientific devices

    NASA Astrophysics Data System (ADS)

    Perepech, B. L.; Rumiantsev, V. P.; Galkin, V. M.; Shakhvorostov, S. V.; Rvachev, S. S.

    1991-02-01

    The paper describes the NA SBS 9 systems developed for the ninth Cosmos-2044 biological test mission. The NA SBS 9 life support systems designed for monkeys and rats follow standard design of BIOS-Vivarium and BIOS-Primate units. The main features of NA SBS 9 include the use of a recently developed HF physiological data recorder Skat-3; the incorporation into BIOS-Primate of two units intended for biorhythmic studies (the BBI-Zh system for studying beetles and the VITALOG developed by NASA for studies on monkeys); and a new version of BIOS-Primate system incorporating a capacitance-link and an inductance-link temperature transmitters and a brain tissue oxygen tension control channel.

  3. Hyperbaric oxygen (HBO2) treatment for a failing facial flap.

    PubMed

    McCrary, Brian F

    2007-01-01

    Hyperbaric oxygen (HBO2) is an approved treatment for 13 pathological entities. One of these indications--a failing facial flap--is presented in this case report of a traumatic wound to the face and right axilla after an unprovoked pit bull attack on a 4 year old girl. Surgical repair was started acutely but the facial flap became congested and ischaemic, indicating deterioration of the blood supply. HBO2 treatments were initiated twice a day, resulting in remarkably decreased swelling and discomfort after the first treatment. Leeching was also used to assist with reduction of venous congestion in the flap. The patient was discharged 5 days later with a well perfused, mostly intact, incision with minimal tenderness. Surgical repair was required for a small area of wound dehiscence. Photographs documenting the patient's progress with HBO2 are presented. A discussion of the mechanisms of action of HBO2 and its beneficial effects is provided in this case.

  4. Safety of Propofol for Oxygenator Exchange in Extracorporeal Membrane Oxygenation.

    PubMed

    Hohlfelder, Benjamin; Szumita, Paul M; Lagambina, Susan; Weinhouse, Gerald; Degrado, Jeremy R

    The purpose of this analysis is to describe the safety of propofol administration in adult extracorporeal membrane oxygenation (ECMO) patients. We performed a prospective cohort analysis of patients using ECMO at Brigham and Women's Hospital between February 2013 and October 2015. Patients were included if they used ECMO for at least 48 hours. The major end-point of the analysis was the median oxygenator lifespan. Oxygenator exchanges were analyzed by the number of patients requiring an oxygenator exchange and the number of oxygenator exchanges per ECMO day. A priori analysis was performed by comparing the outcomes between patients who did and did not receive propofol during their ECMO course. During the study, 43 patients were included in the analysis. Sixteen patients used propofol during their ECMO course. There were 12 oxygenator exchanges during therapy. Oxygenator exchange occurred on 1.8% of ECMO days. The median oxygenator lifespan was 7 days. Patients who used propofol had a significantly longer oxygenator lifespan (p = 0.02). Among patients who received propofol, patients who required oxygenator exchange used a significantly lower median daily dose of propofol (p < 0.001). The use of propofol appears safe in ECMO with regards to oxygenator viability. Contrary to expected, oxygenator lifespan was significantly longer among patients who received propofol.

  5. Integrated oxygen recovery system

    NASA Technical Reports Server (NTRS)

    Lee, M. Gene; Davenport, Ronald J.

    1993-01-01

    Life Systems has conceptualized an innovative Integrated Oxygen Recovery System (IORS) applicable to advanced mission air revitalization. The IORS provides the capability to electrochemically generate metabolic oxygen (O2) and recover O2 from the space habitat atmosphere via a carbon dioxide (CO2) reduction process within a single assembly. To achieve this capability, the IORS utilizes a Solid Metal Cathode (SMC) water electrolysis unit that simultaneously serves as the Sabatier CO2 reduction reactor. The IORS enables two major life support systems currently baselined in closed loop air revitalization systems to be combined into one smaller, less complex system. This concept reduces fluidic and electrical interface requirements and eliminates a hydrogen (H2) interface. Life Systems is performing an evaluation of the IORS process directed at demonstrating performance and quantifying key physical characteristics including power, weight, and volume. Technical progress achieved during the first two months of the program is summarized.

  6. High pressure oxygen furnace

    DOEpatents

    Morris, Donald E.

    1992-01-01

    A high temperature high pressure oxygen furnace having a hybrid partially externally heated construction is disclosed. A metallic bar fabricated from an alloy having a composition of at least 45% nickel, 15% chrome, and 10% tungsten is utilized (the preferred alloy including 55% nickel, 22% chrome, 14% tungsten, 2% molybdenum, 3% iron (maximum) and 5% cobalt (maximum). The disclosed alloy is fabricated into 11/4 inch bar stock and has a length of about 17 inches. This bar stock is gun drilled for over 16 inches of its length with 0.400 inch aperture to define a closed high temperature, high pressure oxygen chamber. The opposite and closed end of the bar is provided with a small support aperture into which both a support and a thermocouple can be inserted. The closed end of the gun drilled bar is inserted into an oven, preferably heated by standard nickel chrome electrical elements and having a heavily insulated exterior.

  7. High pressure oxygen furnace

    DOEpatents

    Morris, D.E.

    1992-07-14

    A high temperature high pressure oxygen furnace having a hybrid partially externally heated construction is disclosed. A metallic bar fabricated from an alloy having a composition of at least 45% nickel, 15% chrome, and 10% tungsten is utilized, the preferred alloy including 55% nickel, 22% chrome, 14% tungsten, 2% molybdenum, 3% iron (maximum) and 5% cobalt (maximum). The disclosed alloy is fabricated into 11/4 inch bar stock and has a length of about 17 inches. This bar stock is gun drilled for over 16 inches of its length with 0.400 inch aperture to define a closed high temperature, high pressure oxygen chamber. The opposite and closed end of the bar is provided with a small support aperture into which both a support and a thermocouple can be inserted. The closed end of the gun drilled bar is inserted into an oven, preferably heated by standard nickel chrome electrical elements and having a heavily insulated exterior. 5 figs.

  8. Oxygenic photosynthesis without galactolipids

    PubMed Central

    Awai, Koichiro; Ohta, Hiroyuki; Sato, Naoki

    2014-01-01

    The thylakoid membranes of oxygenic photosynthetic organisms are dominated by the galactolipids monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG). In cyanobacteria, MGDG is synthesized via monoglucosyldiacylglycerol (GlcDG). However, the putative epimerase involved in the conversion of GlcDG to MGDG has not been identified. Here we report the identification of the gene for the glucolipid epimerase (mgdE) by comparative genomic analysis. Knockout mutants of mgdE in Synechocystis sp. PCC 6803 lacked both MGDG and DGDG and accumulated GlcDG. The mutants did possess thylakoid membranes and showed normal maximal photosynthetic activity, albeit with reduced utilization of light energy. These results cast doubt on the long-standing belief that oxygenic photosynthesis is absolutely dependent on galactolipids. PMID:25197079

  9. Integrated oxygen recovery system

    NASA Technical Reports Server (NTRS)

    Lee, M. Gene; Davenport, Ronald J.

    1993-01-01

    Life Systems has conceptualized an innovative Integrated Oxygen Recovery System (IORS) applicable to advanced mission air revitalization. The IORS provides the capability to electrochemically generate metabolic oxygen (O2) and recover O2 from the space habitat atmosphere via a carbon dioxide (CO2) reduction process within a single assembly. To achieve this capability, the IORS utilizes a Solid Metal Cathode (SMC) water electrolysis unit that simultaneously serves as the Sabatier CO2 reduction reactor. The IORS enables two major life support systems currently baselined in closed loop air revitalization systems to be combined into one smaller, less complex system. This concept reduces fluidic and electrical interface requirements and eliminates a hydrogen (H2) interface. Life Systems is performing an evaluation of the IORS process directed at demonstrating performance and quantifying key physical characteristics including power, weight, and volume. The results of the checkout, shakedown, and initial parametric tests are summarized.

  10. Oxygen Transport Ceramic Membranes

    SciTech Connect

    S. Bandopadhyay; T. Nithyanantham; X.-D Zhou; Y-W. Sin; H.U. Anderson; Alan Jacobson; C.A. Mims

    2005-08-01

    The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. In the previous research, the reference point of oxygen occupancy was determined and verified. In the current research, the oxygen occupancy was investigated at 1200 C as a function of oxygen activity and compared with that at 1000 C. The cause of bumps at about 200 C was also investigated by using different heating and cooling rates during TGA. The fracture toughness of LSFT and dual phase membranes at room temperature is an important mechanical property. Vicker's indentation method was used to evaluate this toughness. Through this technique, a K{sub Ic} (Mode-I Fracture Toughness) value is attained by means of semi-empirical correlations between the indentation load and the length of the cracks emanating from the corresponding Vickers indentation impression. In the present investigation, crack propagation behavior was extensively analyzed in order to understand the strengthening mechanisms involved in the non-transforming La based ceramic composites. Cracks were generated using Vicker's indenter and used to identify and evaluate the toughening mechanisms involved. Preliminary results of an electron microscopy study of the origin of the slow kinetics on reduction of ferrites have been obtained. The slow kinetics appear to be related to a non-equilibrium reduction pathway that initially results in the formation of iron particles. At long times, equilibrium can be reestablished with recovery of the perovskite phase. Modeling of the isotopic transients on operating membranes (LSCrF-2828 at 900 C) and a ''frozen'' isotope profile have been analyzed in conjunction with a 1-D model to reveal the gradient in oxygen diffusivity through the membrane under conditions of high chemical gradients.

  11. Oxygen Transport Ceramic Membranes

    SciTech Connect

    S. Bandopadhyay; T. Nithyanantham; X.-D Zhou; Y-W. Sin; H.U. Anderson; Alan Jacobson; C.A. Mims

    2005-02-01

    The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. The in situ electrical conductivity and Seebeck coefficient measurements were made on LSFT at 1000 and 1200 C over the oxygen activity range from air to 10{sup -15} atm. The electrical conductivity measurements exhibited a p to n type transition at an oxygen activity of 1 x 10{sup -10} at 1000 C and 1 x 10{sup -6} at 1200 C. Thermogravimetric studies were also carried out over the same oxygen activities and temperatures. Based on the results of these measurements, the chemical and mechanical stability range of LSFT were determined and defect structure was established. The studies on the fracture toughness of the LSFT and dual phase membranes exposed to air and N{sub 2} at 1000 C was done and the XRD and SEM analysis of the specimens were carried out to understand the structural and microstructural changes. The membranes that are exposed to high temperatures at an inert and a reactive atmosphere undergo many structural and chemical changes which affect the mechanical properties. A complete transformation of fracture behavior was observed in the N{sub 2} treated LSFT samples. Further results to investigate the origin of the slow kinetics on reduction of ferrites have been obtained. The slow kinetics appear to be related to a non-equilibrium reduction pathway that initially results in the formation of iron particles. At long times, equilibrium can be reestablished with recovery of the perovskite phase. Recent results on transient kinetic data are presented. The 2-D modeling of oxygen movement has been undertaken in order to fit isotope data. The model is used to study ''frozen'' profiles in patterned or composite membranes.

  12. Transport properties of oxygen

    NASA Technical Reports Server (NTRS)

    Roder, H. M.

    1983-01-01

    Tables of viscosity, thermal conductivity, and thermal diffusivity of oxygen as a function of temperature and pressure from the triple point to 320 K and at pressures to 100 MPa are presented. Auxiliary tables in engineering units are also given. Viscosity and thermal conductivity are calculated from published correlations. Density and specific heat at constant pressure, required to calculate thermal diffusivity, are obtained from an equation of state. The Prandtl number can be obtained quite easily from the values tabulated.

  13. 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.

  14. 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.

  15. Biological Remediation of Petroleum Contaminants

    NASA Astrophysics Data System (ADS)

    Kuhad, Ramesh Chander; Gupta, Rishi

    Large volumes of hazardous wastes are generated in the form of oily sludges and contaminated soils during crude oil transportation and processing. Although many physical, chemical and biological treatment technologies are available for petroleum contaminants petroleum contaminants in soil, biological methods have been considered the most cost-effective. Practical biological remediation methods typically involve direct use of the microbes naturally occurring in the contaminated environment and/or cultured indigenous or modified microorganisms. Environmental and nutritional factors, including the properties of the soil, the chemical structure of the hydrocarbon(s), oxygen, water, nutrient availability, pH, temperature, and contaminant bioavailability, can significantly affect the rate and the extent of hydrocarbon biodegradation hydrocarbon biodegradation by microorganisms in contaminated soils. This chapter concisely discusses the major aspects of bioremediation of petroleum contaminants.

  16. Atmospheric Oxygen Photoabsorption

    NASA Technical Reports Server (NTRS)

    Slanger, Tom G.

    1996-01-01

    The work conducted on this grant was devoted to various aspects of the photophysics and photochemistry of the oxygen molecule. Predissociation linewidths were measured for several vibrational levels in the O2(B3 Sigma(sub u)(sup -)) state, providing good agreement with other groups working on this important problem. Extensive measurements were made on the loss kinetics of vibrationally excited oxygen, where levels between v = 5 and v = 22 were investigated. Cavity ring-down spectroscopy was used to measure oscillator strengths in the oxygen Herzberg bands. The great sensitivity of this technique made it possible to extend the known absorption bands to the dissociation limit as well as providing many new absorption lines that seem to be associated with new O2 transitions. The literature concerning the Herzberg band strengths was evaluated in light of our new measurements, and we made recommendations for the appropriate Herzberg continuum cross sections to be used in stratospheric chemistry. The transition probabilities for all three Herzberg band systems were re-evaluated, and we are recommending a new set of values.

  17. Transtracheal oxygen therapy.

    PubMed

    Christopher, Kent L; Schwartz, Michael D

    2011-02-01

    Transtracheal oxygen therapy (TTO) has been used for long-term oxygen therapy for nearly 30 years. Numerous investigators have explored the potential benefits of TTO. Those results are reviewed in this article. TTO is best viewed not as a catheter but as a program for care. This article discusses patient selection for TTO. Publications evaluating complications are reviewed. In the past, a modified Seldinger technique (MST) was used for the creation of the tracheocutaneous fistula. The rather long program required for tract maturation with MST was labor-intensive and required substantial patient education and monitoring, particularly during the immature tract phase. Minor complications were not infrequent. More recently, the Lipkin method has been used to create a surgical tract under conscious sedation with topical anesthesia. The procedure is safe and well tolerated. Transtracheal oxygen is initiated the day following the procedure. Similarly, the tract matures in 7 to 10 days rather than the 6 to 8 weeks with MST. More rapid healing time and superior tract characteristics substantially reduce complications. The TTO program tailored for the Lipkin procedure is shortened, streamlined, and much less labor-intensive. Optimal outcomes with the TTO program require a committed pulmonologist, respiratory therapist, nurse, and surgeon (for the Lipkin procedure). This article discusses new directions in the use of transtracheal gas delivery, including the management of obstructive sleep apnea. Preliminary investigations regarding transtracheal augmented ventilation are presented. These include nocturnal use in severe chronic lung disease and liberation from prolonged mechanical ventilation.

  18. Crusts: biological

    USGS Publications Warehouse

    Belnap, Jayne; Elias, Scott A.

    2013-01-01

    Biological soil crusts, a community of cyanobacteria, lichens, mosses, and fungi, are an essential part of dryland ecosystems. They are critical in the stabilization of soils, protecting them from wind and water erosion. Similarly, these soil surface communities also stabilized soils on early Earth, allowing vascular plants to establish. They contribute nitrogen and carbon to otherwise relatively infertile dryland soils, and have a strong influence on hydrologic cycles. Their presence can also influence vascular plant establishment and nutrition.

  19. Ancient Oceans Had Less Oxygen

    ERIC Educational Resources Information Center

    King, Angela G.

    2004-01-01

    The amount of dissolved oxygen in the oceans in the mid-Proterozoic period has evolutionary implications since essential trace metals are redox sensitive. The findings suggest that there is global lack of oxygen in seawater.

  20. Surface acoustic wave oxygen sensor

    NASA Technical Reports Server (NTRS)

    Collman, James P.; Oglesby, Donald M.; Upchurch, Billy T.; Leighty, Bradley D.; Zhang, Xumu; Herrmann, Paul C.

    1994-01-01

    A surface acoustic wave (SAW) device that responds to oxygen pressure was developed by coating a 158 MHz quartz surface acoustic wave (SAW) device with an oxygen binding agent. Two types of coatings were used. One type was prepared by dissolving an oxygen binding agent in a toluene solution of a copolymer containing the axial ligand. A second type was prepared with an oxygen binding porphyrin solution containing excess axial ligand without a polymer matrix. In the polymer based coatings, the copolymer served to provide the axial ligand to the oxygen binding agent and as a coating matrix on the surface of the SAW device. The oxygen sensing SAW device has been shown to bind oxygen following a Langmuir isotherm and may be used to measure the equilibrium constant of the oxygen binding compound in the coating matrix.

  1. Marine biology

    SciTech Connect

    Thurman, H.V.; Webber, H.H.

    1984-01-01

    This book discusses both taxonomic and ecological topics on marine biology. Full coverage of marine organisms of all five kingdoms is provided, along with interesting and thorough discussion of all major marine habitats. Organization into six major parts allows flexibility. It also provides insight into important topics such as disposal of nuclear waste at sea, the idea that life began on the ocean floor, and how whales, krill, and people interact. A full-color photo chapter reviews questions, and exercises. The contents are: an overview marine biology: fundamental concepts/investigating life in the ocean; the physical ocean, the ocean floor, the nature of water, the nature and motion of ocean water; general ecology, conditions for life in the sea, biological productivity and energy transfer; marine organisms; monera, protista, mycota and metaphyta; the smaller marine animals, the large animals marine habitats, the intertidal zone/benthos of the continental shelf, the photic zone, the deep ocean, the ocean under stress, marine pollution, appendix a: the metric system and conversion factors/ appendix b: prefixes and suffixes/ appendix c: taxonomic classification of common marine organisms, and glossary, and index.

  2. Oxygen Transport Membranes

    SciTech Connect

    S. Bandopadhyay

    2008-08-30

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

  3. Oxygen Transport Ceramic Membranes

    SciTech Connect

    S. Bandopadhyay; N. Nagabhushana; T. Nithyanantham; X.-D Zhou; Y-W. Sin; H.U. Anderson; Alan Jacobson; C.A. Mims

    2005-02-01

    The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. Thermogravimetric analysis (TGA) was carried out on La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} to investigate oxygen deficiency ({delta}) of the sample. The TGA was performed in a controlled atmosphere using oxygen, argon, carbon monoxide and carbon dioxide with adjustable gas flow rates. In this experiment, the weight loss and gain of La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} was directly measured by TGA. The weight change of the sample was evaluated at between 600 and 1250 C in air or 1000 C as a function of oxygen partial pressure. The oxygen deficiencies calculated from TGA data as a function of oxygen activity and temperature will be estimated and compared with that from neutron diffraction measurement in air. The LSFT and LSFT/CGO membranes were fabricated from the powder obtained from Praxair Specialty Ceramics. The sintered membranes were subjected to microstructure analysis and hardness analysis. The LSFT membrane is composed of fine grains with two kinds of grain morphology. The grain size distribution was characterized using image analysis. In LSFT/CGO membrane a lot of grain pullout was observed from the less dense, porous phase. The hardness of the LSFT and dual phase membranes were studied at various loads. The hardness values obtained from the cross section of the membranes were also compared to that of the values obtained from the surface. An electrochemical cell has been designed and built for measurements of the Seebeck coefficient as a function of temperature and pressure. Measurements on La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} as a function of temperature an oxygen partial pressure are reported. Further analysis of the dilatometry data obtained previously is presented. A series of isotope transients

  4. Oxygen Sag and Stream Purification.

    ERIC Educational Resources Information Center

    Neal, Larry; Herwig, Roy

    1978-01-01

    Presents a literature review of water quality related to oxygen sag and stream purification, covering publications of 1976-77. This review includes: (1) self-purification models; (2) oxygen demand; and (3) reaeration and oxygen transfer. A list of 60 references is also presented. (HM)

  5. Modeling Variable Phanerozoic Oxygen Effects on Physiology and Evolution.

    PubMed

    Graham, Jeffrey B; Jew, Corey J; Wegner, Nicholas C

    2016-01-01

    Geochemical approximation of Earth's atmospheric O2 level over geologic time prompts hypotheses linking hyper- and hypoxic atmospheres to transformative events in the evolutionary history of the biosphere. Such correlations, however, remain problematic due to the relative imprecision of the timing and scope of oxygen change and the looseness of its overlay on the chronology of key biotic events such as radiations, evolutionary innovation, and extinctions. There are nevertheless general attributions of atmospheric oxygen concentration to key evolutionary changes among groups having a primary dependence upon oxygen diffusion for respiration. These include the occurrence of Devonian hypoxia and the accentuation of air-breathing dependence leading to the origin of vertebrate terrestriality, the occurrence of Carboniferous-Permian hyperoxia and the major radiation of early tetrapods and the origins of insect flight and gigantism, and the Mid-Late Permian oxygen decline accompanying the Permian extinction. However, because of variability between and error within different atmospheric models, there is little basis for postulating correlations outside the Late Paleozoic. Other problems arising in the correlation of paleo-oxygen with significant biological events include tendencies to ignore the role of blood pigment affinity modulation in maintaining homeostasis, the slow rates of O2 change that would have allowed for adaptation, and significant respiratory and circulatory modifications that can and do occur without changes in atmospheric oxygen. The purpose of this paper is thus to refocus thinking about basic questions central to the biological and physiological implications of O2 change over geological time.

  6. 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.

  7. Oxygen Transport Ceramic Membranes

    SciTech Connect

    S. Bandopadhyay; T. Nithyanantham

    2006-12-31

    Ti doping on La{sub 1-x}Sr{sub x}FeO{sub 3-{delta}} (LSF) tends to increase the oxygen equilibration kinetics of LSF in lower oxygen activity environment because of the high valence state of Ti. However, the addition of Ti decreases the total conductivity because the acceptor ([Sr{prime}{sub La}]) is compensated by the donor ([Ti{sub Fe}{sup {sm_bullet}}]) which decreases the carrier concentration. The properties of La{sub 0.2}Sr{sub 0.8}Fe{sub 1-x}Ti{sub x}O{sub 3-{delta}} (LSFT, x = 0.45) have been experimentally and theoretically investigated to elucidate (1) the dependence of oxygen occupancy and electrochemical properties on temperature and oxygen activity by thermogravimetric analysis (TGA) and (2) the electrical conductivity and carrier concentration by Seebeck coefficient and electrical measurements. In the present study, dual phase (La{sub 0.2}Sr{sub 0.8}Fe{sub 0.6}Ti{sub 0.4}O{sub 3-{delta}}/Ce{sub 0.9}Gd{sub 0.1}O{sub 2-{delta}}) membranes have been evaluated for structural properties such as hardness, fracture toughness and flexural strength. The effect of high temperature and slightly reducing atmosphere on the structural properties of the membranes was studied. The flexural strength of the membrane decreases upon exposure to slightly reducing conditions at 1000 C. The as-received and post-fractured membranes were characterized using XRD, SEM and TG-DTA to understand the fracture mechanisms. Changes in structural properties of the composite were sought to be correlated with the physiochemical features of the two-phases. We have reviewed the electrical conductivity data and stoichiometry data for La{sub 0.2}Sr{sub 0.8}Cr{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}} some of which was reported previously. Electrical conductivity data for La{sub 0.2}Sr{sub 0.8}Cr{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}} (LSCrF) were obtained in the temperature range, 752 {approx} 1055 C and in the pO{sub 2} range, 10{sup -18} {approx} 0.5 atm. The slope of the plot of log {sigma} vs

  8. Drivers of summer oxygen depletion in the central North Sea

    NASA Astrophysics Data System (ADS)

    Queste, Bastien Y.; Fernand, Liam; Jickells, Timothy D.; Heywood, Karen J.; Hind, Andrew J.

    2016-02-01

    In stratified shelf seas, oxygen depletion beneath the thermocline is a result of a greater rate of biological oxygen demand than the rate of supply of oxygenated water. Suitably equipped gliders are uniquely placed to observe both the supply through the thermocline and the consumption of oxygen in the bottom layers. A Seaglider was deployed in the shallow (≍ 100 m) stratified North Sea in a region of known low oxygen during August 2011 to investigate the processes regulating supply and consumption of dissolved oxygen below the pycnocline. The first deployment of such a device in this area, it provided extremely high-resolution observations, 316 profiles (every 16 min, vertical resolution of 1 m) of conductivity, temperature, and depth (CTD), dissolved oxygen concentrations, backscatter, and fluorescence during a 3-day deployment.The high temporal resolution observations revealed occasional small-scale events (< 200 m or 6 h) that supply oxygenated water to the bottom layer at a rate of 2 ± 1 µmol dm-3 day-1. Benthic and pelagic oxygen sinks, quantified through glider observations and past studies, indicate more gradual background consumption rates of 2.5 ± 1 µmol dm-3 day-1. This budget revealed that the balance of oxygen supply and demand is in agreement with previous studies of the North Sea. However, the glider data show a net oxygen consumption rate of 2.8 ± 0.3 µmol dm-3 day-1, indicating a localized or short-lived (< 200 m or 6 h) increase in oxygen consumption rates. This high rate of oxygen consumption is indicative of an unidentified oxygen sink. We propose that this elevated oxygen consumption is linked to localized depocentres and rapid remineralization of resuspended organic matter.The glider proved to be an excellent tool for monitoring shelf sea processes despite challenges to glider flight posed by high tidal velocities, shallow bathymetry, and very strong density gradients. The direct observation of these processes allows more up to date

  9. Simultaneous Monitoring of Vascular Oxygenation and Tissue Oxygen Tension of Breast Tumors under Hyperbaric Oxygen Exposure

    DTIC Science & Technology

    2006-04-01

    FOXY system, on various rat breast tumor size (months 14- 30). Instead of single-channel NIRS, steady-state diffuse reflectance spectroscopy (SSDRS...combination of normobaric and hyperbaric oxygen interventions) simultaneously monitored by steady-state diffuse reflectance spectroscopy (SSDRS) and...simultaneously by steady-state diffuse reflectance spectroscopy (SSDRS) and FOXY oxygen sensor in response to normobaric and hyperbaric oxygen

  10. Solar Forbidden Oxygen, Revisited

    NASA Astrophysics Data System (ADS)

    Ayres, Thomas R.

    2008-10-01

    Recent large reductions in the solar oxygen abundance, based on synthesis of photospheric O I, OH, and CO absorptions with 3D convection models, have provoked consternation in the helioseismology community: the previous excellent agreement between measured p-mode oscillation frequencies and predictions based on the recommended epsilonO of a decade ago (680 parts per million [ppm] relative to hydrogen) unravels at the new low value (460 ppm). In an attempt to reconcile these conflicting results, the formation of pivotal [O I] λ6300, which is blended with a weak Ni I line, has been reconsidered, exploiting an alternative 3D model (albeit only a single temporal snapshot). And while there are several areas of agreement with the earlier [O I] studies of Allende Prieto, Asplund, and others, there is one crucial point of disagreement: the epsilonO derived here is significantly larger, 650 +/- 65 ppm (although at the expense of a ~30% weaker Ni I line than expected from the recommended nickel abundance). One innovation is a more robust treatment of the solar wavelengths: the balance between the components of the [O I] + Ni I blend is sensitive to velocity errors of only a few hundred m s-1. A second improvement is enforcement of a "continuum calibration" to ensure a self-consistent 3D temperature scale. Because of the renewed agreement between the linchpin tracer [O I] and seismic oxygen, the proposed downward slump of the solar metallicity and the perceived "oxygen crisis" now can be said to rest on less secure footings.

  11. Physics and Size in Biological Systems.

    ERIC Educational Resources Information Center

    Barnes, George

    1989-01-01

    Described is the subject of biological scaling for physics teachers including examples and in-depth reading. Topics are elements of scaling, terminal velocities, Lilliputian and Brobdingnagian, brain evolution, dolphin echolocation, surface tension, gravity change, food and oxygen, and seeing. Ten references on physics and size, and ten questions…

  12. Oxygen supplies in disaster management.

    PubMed

    Blakeman, Thomas C; Branson, Richard D

    2013-01-01

    Mass casualty events and disasters, both natural and human-generated, occur frequently around the world and can generate scores of injured or ill victims in need of resources. Of the available medical supplies, oxygen remains the critical consumable resource in disaster management. Strategic management of oxygen supplies in disaster scenarios remains a priority. Hospitals have large supplies of liquid oxygen and a supply of compressed gas oxygen cylinders that allow several days of reserve, but a large influx of patients from a disaster can strain these resources. Most backup liquid oxygen supplies are attached to the main liquid system and supply line. In the event of damage to the main system, the reserve supply is rendered useless. The Strategic National Stockpile supplies medications, medical supplies, and equipment to disaster areas, but it does not supply oxygen. Contracted vendors can deliver oxygen to alternate care facilities in disaster areas, in the form of concentrators, compressed gas cylinders, and liquid oxygen. Planning for oxygen needs following a disaster still presents a substantial challenge, but alternate care facilities have proven to be valuable in relieving pressure from the mass influx of patients into hospitals, especially for those on home oxygen who require only an electrical source to power their oxygen concentrator.

  13. Long-term variations in the dissolved oxygen budget of an urbanized tidal river: The upper Delaware Estuary

    NASA Astrophysics Data System (ADS)

    Tomaso, Daniel J.; Najjar, Raymond G.

    2015-06-01

    The dissolved oxygen budget in the upper Delaware Estuary between 1970 and 2014 was inferred from oxygen concentration measurements using a box model approach. The region was found to be a net biogeochemical sink of oxygen, with net oxygen consumption greater in the tidal fresh portion than in the oligohaline portion. Net oxygen consumption decreased from the 1970s to the 1990s by roughly a factor of 2 before increasing slightly in the 2000s. The dramatic decline in oxygen consumption was presumably due to improvements in wastewater treatment, though a comparison with biological oxygen demand measurements in wastewater was equivocal. Nonalgal oxygen consumption (i.e., oxygen consumption due to heterotrophic respiration and nitrification) was computed as the sum of the estimated net oxygen consumption and historical measurements of primary production. Nonalgal oxygen consumption was found to be highly seasonal and positively correlated with temperature, with Q10 values ranging between 1.4 and 2.3. Annual nonalgal oxygen consumption was found to be several times annual primary production. Exchange with the atmosphere is the main process that balances the net oxygen consumption throughout the study region, with advection also an important process in the tidal fresh portion. Decadal scale variability in oxygen concentration, including the recent decline in the 2000s, appears to be mainly driven by biological, not physical, processes.

  14. Allometric Scaling in Biology

    NASA Astrophysics Data System (ADS)

    Banavar, Jayanth

    2009-03-01

    The unity of life is expressed not only in the universal basis of inheritance and energetics at the molecular level, but also in the pervasive scaling of traits with body size at the whole-organism level. More than 75 years ago, Kleiber and Brody and Proctor independently showed that the metabolic rates, B, of mammals and birds scale as the three-quarter power of their mass, M. Subsequent studies showed that most biological rates and times scale as M-1/4 and M^1/4 respectively, and that these so called quarter-power scaling relations hold for a variety of organisms, from unicellular prokaryotes and eukaryotes to trees and mammals. The wide applicability of Kleiber's law, across the 22 orders of magnitude of body mass from minute bacteria to giant whales and sequoias, raises the hope that there is some simple general explanation that underlies the incredible diversity of form and function. We will present a general theoretical framework for understanding the relationship between metabolic rate, B, and body mass, M. We show how the pervasive quarter-power biological scaling relations arise naturally from optimal directed resource supply systems. This framework robustly predicts that: 1) whole organism power and resource supply rate, B, scale as M^3/4; 2) most other rates, such as heart rate and maximal population growth rate scale as M-1/4; 3) most biological times, such as blood circulation time and lifespan, scale as M^1/4; and 4) the average velocity of flow through the network, v, such as the speed of blood and oxygen delivery, scales as M^1/12. Our framework is valid even when there is no underlying network. Our theory is applicable to unicellular organisms as well as to large animals and plants. This work was carried out in collaboration with Amos Maritan along with Jim Brown, John Damuth, Melanie Moses, Andrea Rinaldo, and Geoff West.

  15. Synthetic mononuclear nonheme iron-oxygen intermediates.

    PubMed

    Nam, Wonwoo

    2015-08-18

    Mononuclear nonheme iron-oxygen species, such as iron-superoxo, -peroxo, -hydroperoxo, and -oxo, are key intermediates involved in dioxygen activation and oxidation reactions catalyzed by nonheme iron enzymes. Because these iron-oxygen intermediates are short-lived due to their thermal instability and high reactivity, it is challenging to investigate their structural and spectroscopic properties and reactivity in the catalytic cycles of the enzymatic reactions themselves. One way to approach such problems is to synthesize biomimetic iron-oxygen complexes and to tune their geometric and electronic structures for structural characterization and reactivity studies. Indeed, a number of biologically important iron-oxygen species, such as mononuclear nonheme iron(III)-superoxo, iron(III)-peroxo, iron(III)-hydroperoxo, iron(IV)-oxo, and iron(V)-oxo complexes, were synthesized recently, and the first X-ray crystal structures of iron(III)-superoxo, iron(III)-peroxo, and iron(IV)-oxo complexes in nonheme iron models were successfully obtained. Thus, our understanding of iron-oxygen intermediates in biological reactions has been aided greatly from the studies of the structural and spectroscopic properties and the reactivities of the synthetic biomimetic analogues. In this Account, we describe our recent results on the synthesis and characterization of mononuclear nonheme iron-oxygen complexes bearing simple macrocyclic ligands, such as N-tetramethylated cyclam ligand (TMC) and tetraamido macrocyclic ligand (TAML). In the case of iron-superoxo complexes, an iron(III)-superoxo complex, [(TAML)Fe(III)(O2)](2-), is described, including its crystal structure and reactivities in electrophilic and nucleophilic oxidative reactions, and its properties are compared with those of a chromium(III)-superoxo complex, [(TMC)Cr(III)(O2)(Cl)](+), with respect to its reactivities in hydrogen atom transfer (HAT) and oxygen atom transfer (OAT) reactions. In the case of iron-peroxo intermediates

  16. Near-infrared uncaging or photosensitizing dictated by oxygen tension

    NASA Astrophysics Data System (ADS)

    Anderson, Erin D.; Gorka, Alexander P.; Schnermann, Martin J.

    2016-11-01

    Existing strategies that use tissue-penetrant near-infrared light for the targeted treatment of cancer typically rely on the local generation of reactive oxygen species. This approach can be impeded by hypoxia, which frequently occurs in tumour microenvironments. Here we demonstrate that axially unsymmetrical silicon phthalocyanines uncage small molecules preferentially in a low-oxygen environment, while efficiently generating reactive oxygen species in normoxic conditions. Mechanistic studies of the uncaging reaction implicate a photoredox pathway involving photoinduced electron transfer to generate a key radical anion intermediate. Cellular studies demonstrate that the biological mechanism of action is O2-dependent, with reactive oxygen species-mediated phototoxicity in normoxic conditions and small molecule uncaging in hypoxia. These studies provide a near-infrared light-targeted treatment strategy with the potential to address the complex tumour landscape through two distinct mechanisms that vary in response to the local O2 environment.

  17. Oxygen Uptake. Operational Control Tests for Wastewater Treatment Facilities. Instructor's Manual [and] Student Workbook.

    ERIC Educational Resources Information Center

    Wooley, John F.

    Biological waste treatment in the activated sludge process is based on the ability of microorganisms to use dissolved oxygen in breaking down soluble organic substances. The oxygen uptake test is a means of measuring the respiration rate of microorganisms in this process. Designed for individuals who have completed National Pollutant Discharge…

  18. 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.

  19. 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.

  20. Oxygen Isotopes in Meteorites

    NASA Astrophysics Data System (ADS)

    Clayton, R. N.

    2003-12-01

    Oxygen isotope abundance variations in meteorites are very useful in elucidating chemical and physical processes that occurred during the formation of the solar system (Clayton, 1993). On Earth, the mean abundances of the three stable isotopes are 16O: 99.76%, 17O: 0.039%, and 18O: 0.202%. It is conventional to express variations in abundances of the isotopes in terms of isotopic ratios, relative to an arbitrary standard, called SMOW (for standard mean ocean water), as follows:The isotopic composition of any sample can then be represented by one point on a "three-isotope plot," a graph of δ17O versus δ18O. It will be seen that such plots are invaluable in interpreting meteoritic data. Figure 1 shows schematically the effect of various processes on an initial composition at the center of the diagram. Almost all terrestrial materials lie along a "fractionation" trend; most meteoritic materials lie near a line of "16O addition" (or subtraction). (4K)Figure 1. Schematic representation of various isotopic processes shown on an oxygen three-isotope plot. Almost all terrestrial materials plot along a line of "fractionation"; most primitive meteoritic materials plot near a line of "16O addition." The three isotopes of oxygen are produced by nucleosynthesis in stars, but by different nuclear processes in different stellar environments. The principal isotope, 16O, is a primary isotope (capable of being produced from hydrogen and helium alone), formed in massive stars (>10 solar masses), and ejected by supernova explosions. The two rare isotopes are secondary nuclei (produced in stars from nuclei formed in an earlier generation of stars), with 17O coming primarily from low- and intermediate-mass stars (<8 solar masses), and 18O coming primarily from high-mass stars (Prantzos et al., 1996). These differences in type of stellar source result in large observable variations in stellar isotopic abundances as functions of age, size, metallicity, and galactic location ( Prantzos

  1. Influence of ionizing radiation on oxygen profiles in different types of multicellular spheroids

    SciTech Connect

    Nylen, T.; Acker, H.; Boelling, B.H.; Holterman, G.; Carlsson, J. )

    1989-11-01

    Human glioma (U-118 MG and U-138 MG), human colorectal adenocarcinoma (HT-29), human thyroid carcinoma (HTh 7), and hamster embryonic lung (V79-379A) spheroids were irradiated with either single doses of 16 or 40 Gy or fractionated doses of eight times 5 Gy. Oxygen profiles in the spheroids were measured with microelectrodes at different times following irradiation, and these profiles were then compared with the oxygen profiles measured in parallel cultured nonirradiated spheroids. No significant radiation-induced changes in the oxygen profiles were seen in any of the spheroids within the first few days after irradiation. The glioma spheroids did not show any significant increase in oxygen tension even after longer times; however, they were growth inhibited, and the number of S-phase cells was strongly suppressed. Increases in oxygen tension did occur in the HT-29 and V79-379A spheroids but only appeared more than a week after irradiation, when degeneration had started. Histological changes and decrease in diameter were seen in the spheroids that started to degenerate about 5 days after irradiation. Thus radiation doses in the therapeutic range did not, for the spheroids studied, produce rapid increases in the oxygen tension. When a change occurred, it appeared rather late and was probably a consequence of cell degeneration.

  2. Hyperthermal atomic oxygen generator

    NASA Technical Reports Server (NTRS)

    Khandelwal, Govind S.; Wu, Dongchuan

    1990-01-01

    Characterization of the transport properties of oxygen through silver was continued. Specifically, experiments measuring the transport through Ag(111), Ag(110), Ag(100) single crystals and through Ag0.05 Zr alloy were completed. In addition, experiments using glow discharge excitation of oxygen to assist in the transport were completed. It was found that the permeability through the different orientations of single crystal Ag was the same, but significant differences existed in the diffusivity. The experimental ratio of diffusivities, however, was in reasonable agreement with theoretical estimates. Since the solubilities of orientations must be the same, this suggests some problems with the assumption K = DS. The glow discharge experiments show that there is a substantial increase in transport (factor of six) when the upstream pressure is dissociated to some fraction of atoms (which have a much higher sticking coefficient). These results indicate that there is a significant surface limitation because of dissociative adsorption of the molecules. Experiments with the Ag0.05 Zr alloy and its high-grain boundary and defect density show a permeability of greater than a factor of two over ordinary polycrystalline Ag, but it is unclear as to whether this is because of enhanced transport through these defects or whether the Zr and defects on the surface increased the sticking coefficient and therefore the transport.

  3. Glovebox oxygen monitoring system

    SciTech Connect

    Haggard, R.

    1993-08-01

    This system is located in the Replacement Tritium Facility (RTF) at the Savannah River Site of the US Department of Energy. The basic system consists of an oxygen sensor module located inside the glovebox and a wall mounted panel located outside the glovebox that contains an electronics package that displays the oxygen level, displays alarms, and sends signals to a facility Distributed Control System (DCS). RTF is a new facility that will be used primarily to load and unload tritium reservoirs, and recycle the tritium for use in existing or new reservoirs. Tritium, an oderless, colorless, gas is a radioactive isotope of hydrogen that is used in modern thermonuclear weapons. Once on-line, RTF will replace other tritium facilities that have been in existence since the 1950`s. Since the entire process at RTF is contained in nitrogen blanketed gloveboxes and features have been provided to recapture fugitive tritium, environmental releases and worker exposure to tritium will be reduced compared to the old facilities.

  4. Composite oxygen transport membrane

    SciTech Connect

    Lu, Zigui; Plonczak, Pawel J.; Lane, Jonathan A.

    2016-11-08

    A method is described of producing a composite oxygen ion membrane and a composite oxygen ion membrane in which a porous fuel oxidation layer and a dense separation layer and optionally, a porous surface exchange layer are formed on a porous support from mixtures of (Ln.sub.1-xA.sub.x).sub.wCr.sub.1-yB.sub.yO.sub.3-.delta. and a doped zirconia. Preferred materials are (La.sub.0.8Sr.sub.0.2).sub.0.95Cr.sub.0.7Fe.sub.0.3O.sub.3-.delta. for the porous fuel oxidation layer, (La.sub.0.8Sr.sub.0.2).sub.0.95Cr.sub.0.5Fe.sub.0.5O.sub.3-.delta. for the dense separation layer, and (La.sub.0.8Sr.sub.0.2).sub.0.95Cr.sub.0.3Fe.sub.0.7O.sub.3-.delta. for the porous surface exchange layer. Firing the said fuel activation and separation layers in nitrogen atmosphere unexpectedly allows the separation layer to sinter into a fully densified mass.

  5. Oxygen-Methane Thruster

    NASA Technical Reports Server (NTRS)

    Pickens, Tim

    2012-01-01

    An oxygen-methane thruster was conceived with integrated igniter/injector capable of nominal operation on either gaseous or liquid propellants. The thruster was designed to develop 100 lbf (approximately 445 N) thrust at vacuum conditions and use oxygen and methane as propellants. This continued development included refining the design of the thruster to minimize part count and manufacturing difficulties/cost, refining the modeling tools and capabilities that support system design and analysis, demonstrating the performance of the igniter and full thruster assembly with both gaseous and liquid propellants, and acquiring data from this testing in order to verify the design and operational parameters of the thruster. Thruster testing was conducted with gaseous propellants used for the igniter and thruster. The thruster was demonstrated to work with all types of propellant conditions, and provided the desired performance. Both the thruster and igniter were tested, as well as gaseous propellants, and found to provide the desired performance using the various propellant conditions. The engine also served as an injector testbed for MSFC-designed refractory combustion chambers made of rhenium.

  6. Composite oxygen transport membrane

    DOEpatents

    Christie, Gervase Maxwell; Lane, Jonathan A.

    2016-11-15

    A method of producing a composite oxygen ion membrane and a composite oxygen ion membrane in which a porous fuel oxidation layer and a dense separation layer and optionally, a porous surface exchange layer are formed on a porous support from mixtures of (Ln.sub.1-xA.sub.x).sub.wCr.sub.1-yB.sub.yO.sub.3-.delta. and a doped zirconia. In the porous fuel oxidation layer and the optional porous surface exchange layer, A is Calcium and in the dense separation layer A is not Calcium and, preferably is Strontium. Preferred materials are (La.sub.0.8Ca.sub.0.2).sub.0.95Cr.sub.0.5Mn.sub.0.5O.sub.3-.delta. for the porous fuel oxidation and optional porous surface exchange layers and (La.sub.0.8Sr.sub.0.2).sub.0.95Cr.sub.0.5Fe.sub.0.5O.sub.3-.delta. for the dense separation layer. The use of such materials allows the membrane to sintered in air and without the use of pore formers to reduce membrane manufacturing costs. The use of materials, as described herein, for forming the porous layers have application for forming any type of porous structure, such as a catalyst support.

  7. Composite oxygen transport membrane

    DOEpatents

    Christie, Gervase Maxwell; Lane, Jonathan A.

    2014-08-05

    A method of producing a composite oxygen ion membrane and a composite oxygen ion membrane in which a porous fuel oxidation layer and a dense separation layer and optionally, a porous surface exchange layer are formed on a porous support from mixtures of (Ln.sub.1-xA.sub.x).sub.wCr.sub.1-yB.sub.yO.sub.3-.delta. and a doped zirconia. In the porous fuel oxidation layer and the optional porous surface exchange layer, A is Calcium and in the dense separation layer A is not Calcium and, preferably is Strontium. Preferred materials are (La.sub.0.8Ca.sub.0.2).sub.0.95Cr.sub.0.5Mn.sub.0.5O.sub.3-.delta. for the porous fuel oxidation and optional porous surface exchange layers and (La.sub.0.8Sr.sub.0.2).sub.0.95Cr.sub.0.5Fe.sub.0.5O.sub.3-.delta. for the dense separation layer. The use of such materials allows the membrane to sintered in air and without the use of pore formers to reduce membrane manufacturing costs. The use of materials, as described herein, for forming the porous layers have application for forming any type of porous structure, such as a catalyst support.

  8. OXYGEN ABUNDANCES IN CEPHEIDS

    SciTech Connect

    Luck, R. E.; Andrievsky, S. M.; Korotin, S. N.; Kovtyukh, V. V. E-mail: serkor@skyline.od.ua E-mail: scan@deneb1.odessa.ua

    2013-07-01

    Oxygen abundances in later-type stars, and intermediate-mass stars in particular, are usually determined from the [O I] line at 630.0 nm, and to a lesser extent, from the O I triplet at 615.7 nm. The near-IR triplets at 777.4 nm and 844.6 nm are strong in these stars and generally do not suffer from severe blending with other species. However, these latter two triplets suffer from strong non-local thermodynamic equilibrium (NLTE) effects and thus see limited use in abundance analyses. In this paper, we derive oxygen abundances in a large sample of Cepheids using the near-IR triplets from an NLTE analysis, and compare those abundances to values derived from a local thermodynamic equilibrium (LTE) analysis of the [O I] 630.0 nm line and the O I 615.7 nm triplet as well as LTE abundances for the 777.4 nm triplet. All of these lines suffer from line strength problems making them sensitive to either measurement complications (weak lines) or to line saturation difficulties (strong lines). Upon this realization, the LTE results for the [O I] lines and the O I 615.7 nm triplet are in adequate agreement with the abundance from the NLTE analysis of the near-IR triplets.

  9. Cyanobacterial Diazotrophy and Earth’s Delayed Oxygenation

    PubMed Central

    Olson, Stephanie L.; Reinhard, Christopher T.; Lyons, Timothy W.

    2016-01-01

    The redox landscape of Earth’s ocean-atmosphere system has changed dramatically throughout Earth history. Although Earth’s protracted oxygenation is undoubtedly the consequence of cyanobacterial oxygenic photosynthesis, the relationship between biological O2 production and Earth’s redox evolution remains poorly understood. Existing models for Earth’s oxygenation cannot adequately explain the nearly 2.5 billion years delay between the origin of oxygenic photosynthesis and the oxygenation of the deep ocean, in large part owing to major deficiencies in our understanding of the coevolution of O2 and Earth’s key biogeochemical cycles (e.g., the N cycle). For example, although possible links between O2 and N scarcity have been previously explored, the consequences of N2 limitation for net biological O2 production have not been examined thoroughly. Here, we revisit the prevailing view that N2 fixation has always been able to keep pace with P supply and discuss the possibility that bioavailable N, rather than P, limited export production for extended periods of Earth’s history. Based on the observation that diazotrophy occurs at the expense of oxygenesis in the modern ocean, we suggest that an N-limited biosphere may be inherently less oxygenic than a P-limited biosphere—and that cyanobacterial diazotrophy was a primary control on the timing and tempo of Earth’s oxygenation by modulating net biogenic O2 fluxes. We further hypothesize that negative feedbacks inhibit the transition between N and P limitation, with the implication that the pervasive accumulation of O2 in Earth’s ocean-atmosphere system may not have been an inevitable consequence of oxygenic photosynthesis by marine cyanobacteria. PMID:27721813

  10. The Swine Plasma Metabolome Chronicles "Many Days" Biological Timing and Functions Linked to Growth

    PubMed Central

    Bromage, Timothy G.; Idaghdour, Youssef; Lacruz, Rodrigo S.; Crenshaw, Thomas D.; Ovsiy, Olexandra; Rotter, Björn; Hoffmeier, Klaus; Schrenk, Friedemann

    2016-01-01

    The paradigm of chronobiology is based almost wholly upon the daily biological clock, or circadian rhythm, which has been the focus of intense molecular, cellular, pharmacological, and behavioral, research. However, the circadian rhythm does not explain biological timings related to fundamental aspects of life history such as rates of tissue/organ/body size development and control of the timing of life stages such as gestation length, age at maturity, and lifespan. This suggests that another biological timing mechanism is at work. Here we focus on a "many days" (multidien) chronobiological period first observed as enigmatic recurring growth lines in developing mammalian tooth enamel that is strongly associate with all adult tissue, organ, and body masses as well as life history attributes such as gestation length, age at maturity, weaning, and lifespan, particularly among the well studied primates. Yet, knowledge of the biological factors regulating the patterning of mammalian life, such as the development of body size and life history structure, does not exist. To identify underlying molecular mechanisms we performed metabolome and genome analyses from blood plasma in domestic pigs. We show that blood plasma metabolites and small non-coding RNA (sncRNA) drawn from 33 domestic pigs over a two-week period strongly oscillate on a 5-day multidien rhythm, as does the pig enamel rhythm. Metabolomics and genomics pathway analyses actually reveal two 5-day rhythms, one related to growth in which biological functions include cell proliferation, apoptosis, and transcription regulation/protein synthesis, and another 5-day rhythm related to degradative pathways that follows three days later. Our results provide experimental confirmation of a 5-day multidien rhythm in the domestic pig linking the periodic growth of enamel with oscillations of the metabolome and genome. This association reveals a new class of chronobiological rhythm and a snapshot of the biological bases that

  11. Cerebral Blood Oxygenation Measurement Based on Oxygen-dependent Quenching of Phosphorescence

    PubMed Central

    Sakadžić, Sava; Roussakis, Emmanuel; Yaseen, Mohammad A.; Mandeville, Emiri T.; Srinivasan, Vivek J.; Arai, Ken; Ruvinskaya, Svetlana; Wu, Weicheng; Devor, Anna; Lo, Eng H.; Vinogradov, Sergei A.; Boas, David A.

    2011-01-01

    pulsed green laser. An example of monitoring the cortical spreading depression based on phosphorescence lifetime of Oxyphor R3 dye was presented. In second demonstration we present a high resolution two-photon pO2 imaging in cortical micro vasculature of a mouse. The experimental setup includes a custom built 2-photon microscope with femtosecond laser, electro-optic modulator, and photon-counting photo multiplier tube. We present an example of imaging the pO2 heterogeneity in the cortical microvasculature including capillaries, using a novel PtP-C343 dye with enhanced 2-photon excitation cross section. Click here to view the related article Synthesis and Calibration of Phosphorescent Nanoprobes for Oxygen Imaging in Biological Systems. PMID:21587157

  12. 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

  13. Modulating temporal and spatial oxygenation over adherent cellular cultures.

    PubMed

    Oppegard, Shawn C; Nam, Ki-Hwan; Carr, Janai R; Skaalure, Stacey C; Eddington, David T

    2009-09-03

    Oxygen is a key modulator of many cellular pathways, but current devices permitting in vitro oxygen modulation fail to meet the needs of biomedical research. A microfabricated insert for multiwell plates has been developed to more effectively control the temporal and spatial oxygen concentration to better model physiological phenomena found in vivo. The platform consists of a polydimethylsiloxane insert that nests into a standard multiwell plate and serves as a passive microfluidic gas network with a gas-permeable membrane aimed to modulate oxygen delivery to adherent cells. Equilibration time is on the order of minutes and a wide variety of oxygen profiles can be attained based on the device design, such as the cyclic profile achieved in this study, and even oxygen gradients to mimic those found in vivo. The proper biological consequences of the device's oxygen delivery were confirmed in cellular models via a proliferation assay and western analysis of the upregulation of hypoxia inducible transcription factor-1alpha. These experiments serve as a demonstration for the platform as a viable tool to increase experimental throughput and permit novel experimental possibilities in any biomedical research lab.

  14. Membrane oxygen dissolution at the Libby, Montana, Superfund Site

    SciTech Connect

    Gantzer, C.J.; Cosgriff, D.

    1995-12-31

    The creosote- and pentachlorophenol-contaminated aquifer at the Libby Superfund Site is being bioremediated using naturally occurring aerobic microorganisms. Water is injected into the aquifer downgradient from the major contaminant source area. Between January 1991 and May 1993, the injection water was amended with hydrogen peroxide at a delivered concentration of approximately 100 mg/L. Theoretically, this hydrogen peroxide decomposed in the aquifer to produce approximately 50 mg/L of biologically available dissolved oxygen. The use of hydrogen peroxide was successful in making portions of the aquifer aerobic, which reduced water-phase contaminant concentrations. In May 1993, the hydrogen peroxide system was replaced by an oxygen generation/dissolution system that reduced the operating costs for oxygenating the aquifer by about $35,000 annually. Oxygen is now generated on site by a pressure-swing absorption oxygen generator and is dissolved by four membrane oxygen dissolution devices. The membrane oxygen dissolution system has operated at the Libby Superfund site for more than 26 months with no loss in performance due to membrane fouling or membrane fatigue.

  15. Fires and Burns Involving Home Medical Oxygen

    MedlinePlus

    ... nfpa.org Fires and Burns Involving Home Medical Oxygen The air is normally 21% oxygen. Oxygen is not flammable, but fire needs it to burn. ¾ When more oxygen is present, any fire that starts will burn ...

  16. The natural history of oxygen.

    PubMed

    Dole, M

    1965-09-01

    The nuclear reactions occurring in the cores of stars which are believed to produce the element oxygen are first described. Evidence for the absence of free oxygen in the early atmosphere of the earth is reviewed. Mechanisms of creation of atmospheric oxygen by photochemical processes are then discussed in detail. Uncertainty regarding the rate of diffusion of water vapor through the cold trap at 70 km altitude in calculating the rate of the photochemical production of oxygen is avoided by using data for the concentration of hydrogen atoms at 90 km obtained from the Meinel OH absorption bands. It is estimated that the present atmospheric oxygen content could have been produced five to ten times during the earth's history. It is shown that the isotopic composition of atmospheric oxygen is not that of photosynthetic oxygen. The fractionation of oxygen isotopes by organic respiration and oxidation occurs in a direction to enhance the O(18) content of the atmosphere and compensates for the O(18) dilution resulting from photosynthetic oxygen. Thus, an oxygen isotope cycle exists in nature.

  17. The Natural History of Oxygen

    PubMed Central

    Dole, Malcolm

    1965-01-01

    The nuclear reactions occurring in the cores of stars which are believed to produce the element oxygen are first described. Evidence for the absence of free oxygen in the early atmosphere of the earth is reviewed. Mechanisms of creation of atmospheric oxygen by photochemical processes are then discussed in detail. Uncertainty regarding the rate of diffusion of water vapor through the cold trap at 70 km altitude in calculating the rate of the photochemical production of oxygen is avoided by using data for the concentration of hydrogen atoms at 90 km obtained from the Meinel OH absorption bands. It is estimated that the present atmospheric oxygen content could have been produced five to ten times during the earth's history. It is shown that the isotopic composition of atmospheric oxygen is not that of photosynthetic oxygen. The fractionation of oxygen isotopes by organic respiration and oxidation occurs in a direction to enhance the O18 content of the atmosphere and compensates for the O18 dilution resulting from photosynthetic oxygen. Thus, an oxygen isotope cycle exists in nature. PMID:5859927

  18. Biological membranes

    PubMed Central

    Watson, Helen

    2015-01-01

    Biological membranes allow life as we know it to exist. They form cells and enable separation between the inside and outside of an organism, controlling by means of their selective permeability which substances enter and leave. By allowing gradients of ions to be created across them, membranes also enable living organisms to generate energy. In addition, they control the flow of messages between cells by sending, receiving and processing information in the form of chemical and electrical signals. This essay summarizes the structure and function of membranes and the proteins within them, and describes their role in trafficking and transport, and their involvement in health and disease. Techniques for studying membranes are also discussed. PMID:26504250

  19. Selected Hydrologic, Water-Quality, Biological, and Sedimentation Characteristics of Laguna Grande, Fajardo, Puerto Rico, March 2007-February 2009

    USGS Publications Warehouse

    Soler-López, Luis R.; Santos, Carlos R.

    2010-01-01

    , which produced 4.9 grams of oxygen per cubic meter per day (1.8 grams of carbon per cubic meter per day). Phytoplankton, the plant and algal component of plankton, produced about 0.8 gram of oxygen per cubic meter per day (0.3 gram of carbon per cubic meter per day). The total diel community respiration rate was 23.4 grams of oxygen per cubic meter per day. The respiration rate ascribed to plankton, which consists of all free floating and swimming organisms in the water column, composed 10 percent of this rate (2.9 grams of oxygen per cubic meter per day); respiration by all other organisms composed the remaining 90 percent (20.5 grams of oxygen per cubic meter per day). Plankton gross productivity was 3.7 grams of oxygen per cubic meter per day, equivalent to about 13 percent of the average gross productivity for the entire community (29.1 grams of oxygen per cubic meter per day). The average phytoplankton biomass values in Laguna Grande ranged from 6.0 to 13.6 milligrams per liter. During the study, Laguna Grande contained a phytoplankton standing crop of approximately 5.8 metric tons. Phytoplankton community had a turnover (renewal) rate of about 153 times per year, or roughly about once every 2.5 days. Fecal indicator bacteria concentrations ranged from 160 to 60,000 colonies per 100 milliliters. Concentrations generally were greatest in areas near residential and commercial establishments, and frequently exceeded current regulatory standards established for Puerto Rico.

  20. Creating biological nanomaterials using synthetic biology

    NASA Astrophysics Data System (ADS)

    Rice, MaryJoe K.; Ruder, Warren C.

    2014-02-01

    Synthetic biology is a new discipline that combines science and engineering approaches to precisely control biological networks. These signaling networks are especially important in fields such as biomedicine and biochemical engineering. Additionally, biological networks can also be critical to the production of naturally occurring biological nanomaterials, and as a result, synthetic biology holds tremendous potential in creating new materials. This review introduces the field of synthetic biology, discusses how biological systems naturally produce materials, and then presents examples and strategies for incorporating synthetic biology approaches in the development of new materials. In particular, strategies for using synthetic biology to produce both organic and inorganic nanomaterials are discussed. Ultimately, synthetic biology holds the potential to dramatically impact biological materials science with significant potential applications in medical systems.

  1. Creating biological nanomaterials using synthetic biology.

    PubMed

    Rice, MaryJoe K; Ruder, Warren C

    2014-02-01

    Synthetic biology is a new discipline that combines science and engineering approaches to precisely control biological networks. These signaling networks are especially important in fields such as biomedicine and biochemical engineering. Additionally, biological networks can also be critical to the production of naturally occurring biological nanomaterials, and as a result, synthetic biology holds tremendous potential in creating new materials. This review introduces the field of synthetic biology, discusses how biological systems naturally produce materials, and then presents examples and strategies for incorporating synthetic biology approaches in the development of new materials. In particular, strategies for using synthetic biology to produce both organic and inorganic nanomaterials are discussed. Ultimately, synthetic biology holds the potential to dramatically impact biological materials science with significant potential applications in medical systems.

  2. Guide for Oxygen Compatibility Assessments on Oxygen Components and Systems

    NASA Technical Reports Server (NTRS)

    Rosales, Keisa R.; Shoffstall, Michael S.; Stoltzfus, Joel M.

    2007-01-01

    Understanding and preventing fire hazards is necessary when designing, maintaining, and operating oxygen systems. Ignition risks can be minimized by controlling heat sources and using materials that will not ignite or will not support burning in the end-use environment. Because certain materials are more susceptible to ignition in oxygen-enriched environments, a compatibility assessment should be performed before the component is introduced into an oxygen system. This document provides an overview of oxygen fire hazards and procedures that are consistent with the latest versions of American Society for Testing and Materials (ASTM) Standards G63 (1999) and G94 (2005) to address fire hazards associated with oxygen systems. This document supersedes the previous edition, NASA Technical Memorandum 104823, Guide for Oxygen Hazards Analyses on Components and Systems (1996). The step-by-step oxygen compatibility assessment method described herein (see Section 4) enables oxygen-system designers, system engineers, and facility managers to determine areas of concern with respect to oxygen compatibility and, ultimately, prevent damage to a system or injury to personnel.

  3. Oxygen Transport Ceramic Membranes

    SciTech Connect

    S. Bandopadhyay; N. Nagabhushana; X.-D Zhou; Q. Cai; J. Yang; W.B. Yelon; W.J. James; H.U. Anderson; Alan Jacobson; C.A. Mims

    2004-05-01

    The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. In this report, in situ neutron diffraction was used to characterize the chemical and structural properties of La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} (here after as L2SF55T) specimen, which was subject to measurements of neutron diffraction from room temperature to 900 C. It was found that space group of R3c yielded a better refinement than a cubic structure of Pm3m. Oxygen occupancy was nearly 3 in the region from room temperature to 700 C, above which the occupancy decreased due to oxygen loss. Dense OTM bars provided by Praxair were loaded to fracture at varying stress rates. Studies were done at room temperature in air and at 1000 C in a specified environment to evaluate slow crack growth behavior. The X-Ray data and fracture mechanisms points to non-equilibrium decomposition of the LSFCO OTM membrane. The non-equilibrium conditions could probably be due to the nature of the applied stress field (stressing rates) and leads to transition in crystal structures and increased kinetics of decomposition. The formations of a Brownmillerite or Sr2Fe2O5 type structures, which are orthorhombic are attributed to the ordering of oxygen vacancies. The cubic to orthorhombic transitions leads to 2.6% increase in strains and thus residual stresses generated could influence the fracture behavior of the OTM membrane. Continued investigations on the thermodynamic properties (stability and phase-separation behavior) and total conductivity of prototype membrane materials were carried out. The data are needed together with the kinetic information to develop a complete model for the membrane transport. Previously characterization, stoichiometry and conductivity measurements for samples of La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} were reported. In this report

  4. Do low oxygen environments facilitate marine invasions? Relative tolerance of native and invasive species to low oxygen conditions.

    PubMed

    Lagos, Marcelo E; Barneche, Diego R; White, Craig R; Marshall, Dustin J

    2017-02-17

    Biological invasions are one of the biggest threats to global biodiversity. Marine artificial structures are proliferating worldwide and provide a haven for marine invasive species. Such structures disrupt local hydrodynamics, which can lead to the formation of oxygen-depleted microsites. The extent to which native fauna can cope with such low oxygen conditions, and whether invasive species, long associated with artificial structures in flow-restricted habitats, have adapted to these conditions remains unclear. We measured water flow and oxygen availability in marinas and piers at the scales relevant to sessile marine invertebrates (mm). We then measured the capacity of invasive and native marine invertebrates to maintain metabolic rates under decreasing levels of oxygen using standard laboratory assays. We found that marinas reduce water flow relative to piers, and that local oxygen levels can be zero in low flow conditions. We also found that for species with erect growth forms, invasive species can tolerate much lower levels of oxygen relative to native species. Integrating the field and laboratory data showed that up to 30% of available microhabitats within low flow environments are physiologically stressful for native species, while only 18% of the same habitat is physiologically stressful for invasive species. These results suggest that invasive species have adapted to low oxygen habitats associated with manmade habitats, and artificial structures may be creating niche opportunities for invasive species.

  5. Radioactive oxygen-15 in the study of cerebral blood flow, blood volume, and oxygen metabolism

    SciTech Connect

    Ter-Pogossian, M.M.; Herscovitch, P.

    1985-10-01

    The short half-life of /sup 15/O led early observers to believe that it was unsuitable for use as a biological tracer. However, initial studies with this nuclide demonstrated its potential usefulness for in vivo, regional physiologic measurements. Subsequently, techniques were developed to measure cerebral blood flow (CBF), blood volume, and oxygen metabolism using intracarotid injection of /sup 15/O-labeled radiopharmaceuticals and highly collimated scintillation probes to record the time course of radioactivity in the brain. The development of positron emission tomography (PET) made possible the in vivo, noninvasive measurement of the absolute concentration of positron-emitting nuclides. A variety of tracer kinetic models were formulated to obtain physiologic measurements from tomographic images of the distribution of 15O-labeled radiopharmaceuticals in the brain. Regional cerebral oxygen metabolism is measured using scan data obtained following the inhalation of /sup 15/O-labeled oxygen. The tracer kinetic models used to measure rCBV, blood flow, and oxygen metabolism will be described and their relative advantages and limitations discussed. Several examples of the use of /sup 15/O tracer methods will be reviewed to demonstrate their widespread applicability to the study of cerebral physiology and pathophysiology. 110 references.

  6. Variation of antioxidative activity and growth enhancement of Brassicaceae induced by low-pressure oxygen plasma

    NASA Astrophysics Data System (ADS)

    Ono, Reoto; Hayashi, Nobuya

    2015-06-01

    The mechanism of growth enhancement induced by active oxygen species generated in an oxygen plasma is investigated. The plant growth enhancement induced by the active oxygen species would relate to an antioxidative activity, which is one of the biological responses. The amount of generated active oxygen species is varied by the oxygen gas pressure in a low-pressure RF glow discharge plasma. The antioxidative activity of sprouts of Brassicaceae induced by the oxygen plasma is maximized at pressures between 30 and 40 Pa, whereas the antioxidative activity becomes small at around 60 and 80 Pa. The pressure dependence of the antioxidative activity of sprout stems is opposite to that of the stem length of the sprouts. The growth enhancement would be induced by the increase in the concentration of active oxygen species in plants owing to the decrease in the amount of antioxidative substances.

  7. Activation of molecular oxygen by infrared laser radiation in pigment-free aerobic systems.

    PubMed

    Krasnovsky, A A; Drozdova, N N; Ivanov, A V; Ambartsumian, R V

    2003-09-01

    With the goal of mimicking the mechanisms of the biological effects of low energy laser irradiation, we have shown that infrared low intensity laser radiation causes oxygenation of the chemical traps of singlet oxygen dissolved in organic media and water saturated by air at normal atmospheric pressure. The photooxygenation rate was directly proportional to the oxygen concentration and strongly inhibited by the singlet oxygen quenchers. The maximum of the photooxygenation action spectrum coincided with the maximum of the oxygen absorption band at 1270 nm. The data provide unambiguous evidence that photooxygenation is determined by the reactive singlet (1)Delta(g )state formed as a result of direct laser excitation of molecular oxygen. Hence, activation of oxygen caused by its direct photoexcitation may occur in natural systems.

  8. Effect of oxygen on the microbial activities of thermophilic anaerobic biomass.

    PubMed

    Pedizzi, C; Regueiro, L; Rodriguez-Verde, I; Lema, J M; Carballa, M

    2016-07-01

    Low oxygen levels (μgO2L(-1)) in anaerobic reactors are quite common and no relevant consequences are expected. On the contrary, higher concentrations could affect the process. This work aimed to study the influence of oxygen (4.3 and 8.8mgO2L(-1), respectively) on the different microbial activities (hydrolytic, acidogenic and methanogenic) of thermophilic anaerobic biomass and on the methanogenic community structure. Batch tests in presence of oxygen were conducted using specific substrates for each biological activity and a blank (with minimum oxygen) was included. No effect of oxygen was observed on the hydrolytic and acidogenic activities. In contrast, the methane production rate decreased by 40% in all oxygenated batches and the development of active archaeal community was slower in presence of 8.8mgO2L(-1). However, despite this sensitivity of methanogens to oxygen at saturation levels, the inhibition was reversible.

  9. 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

  10. Structural Biology Fact Sheet

    MedlinePlus

    ... Home > Science Education > Structural Biology Fact Sheet Structural Biology Fact Sheet Tagline (Optional) Middle/Main Content Area What is structural biology? Structural biology is a field of science focused ...

  11. Tissue oxygen measurement system

    NASA Technical Reports Server (NTRS)

    Soller, Babs R. (Inventor)

    2004-01-01

    A device and method in accordance with the invention for determining the oxygen partial pressure (PO.sub.2) of a tissue by irradiating the tissue with optical radiation such that the light is emitted from the tissue, and by collecting the reflected or transmitted light from the tissue to form an optical spectrum. A spectral processor determines the PO.sub.2 level in tissue by processing this spectrum with a previously-constructed spectral calibration model. The tissue may, for example, be disposed underneath a covering tissue, such as skin, of a patient, and the tissue illuminated and light collected through the skin. Alternatively, direct tissue illumination and collection may be effected with a hand-held or endoscopic probe. A preferred system also determines pH from the same spectrum, and the processor may determine critical conditions and issue warnings based on parameter values.

  12. The oxygen isotopes

    NASA Astrophysics Data System (ADS)

    Brown, B. Alex

    The properties of the oxygen isotopes provide diverse examples of progress made in experiments and theory. This chain of isotopes has been studied from beyond the proton drip line in 12O to beyond the neutron drip line in 25,26O. This short survey starts with the microscopic G matrix approach for 18O of Kuo and Brown in the 1960’s and shows how theory has evolved. The nuclear structure around the doubly-magic nucleus 24O is particularly simple in terms of the nuclear shell model. The nuclear structure around the doubly-magic nucleus 16O exhibits the coexistence of single-particle and collective structure.

  13. Oxygen abundance and convection

    NASA Astrophysics Data System (ADS)

    Van't Veer, C.; Cayrel, R.

    The triplet IR lines of O I near 777 nm are computed with the Kurucz's code, modified to accept several convection models. The program has been run with the MLT algorithm, with l/H = 1.25 and 0.5, and with the Canuto-Mazzitelli and Canuto-Goldman-Mazzitelli approaches, on a metal-poor turnoff-star model atmosphere with Teff=6200 K, log g = 4.3, [Fe/H]= -1.5. The results show that the differences in equivalent widths for the 4 cases do not exceed 2 per cent (0.3 mA). The convection treatment is therefore not an issue for the oxygen abundance derived from the permitted lines.

  14. Oxygen diffusion barrier coating

    NASA Technical Reports Server (NTRS)

    Unnam, Jalaiah (Inventor); Clark, Ronald K. (Inventor)

    1987-01-01

    A method for coating a titanium panel or foil with aluminum and amorphous silicon to provide an oxygen barrier abrogating oxidation of the substrate metal is developed. The process is accomplished with known inexpensive procedures common in materials research laboratories, i.e., electron beam deposition and sputtering. The procedures are conductive to treating foil gage titanium and result in submicron layers which virtually add no weight to the titanium. There are no costly heating steps. The coatings blend with the substrate titanium until separate mechanical properties are subsumed by those of the substrate without cracking or spallation. This method appreciably increases the ability of titanium to mechanically perform in high thermal environments such as those witnessed on structures of space vehicles during re-entry

  15. A Small Oxygen Concentrator

    DTIC Science & Technology

    1985-12-01

    150- S40- 20- 10 0 0 10 i0 30 40 NUIT PRESS=R (psig Figure 7. Percentage of oxygen. versus inlet pressure when using Soc with 131 molecular s ieve. 70...chick valve ano *move the plunger and spring. Disca the plunger; the spring will W• reused. Mill a SS sleeve to 0.535" 0.0. and 0.50" I.D. and press tit...the fjur 1" caps. The i n- side of two of the caps is milled flat to a diameteýr of 7/8". P-Kace one ena of a 10’, length of 1/2" SS tube in each Of

  16. Microdistribution of oxygen in silicon

    NASA Technical Reports Server (NTRS)

    Murgai, A.; Chi, J. Y.; Gatos, H. C.

    1980-01-01

    The microdistribution of oxygen in Czochralskii-grown, p-type silicon crystals was determined by using the SEM in the EBIC mode in conjunction with spreading resistance measurements. When the conductivity remained p-type, bands of contrast were observed in the EBIC image which corresponded to maxima in resistivity. When at the oxygen concentration maxima the oxygen donor concentration exceeded the p-type dopant concentration, an inversion of the conductivity occurred. It resulted in the formation of p-n junctions in a striated configuration and the local inversion of the EBIC image contrast. By heat-treating silicon at 1000 C prior to the activation of oxygen donors, some silicon-oxygen micro-precipitates were observed in the EBIC image within the striated oxygen concentration maxima.

  17. Saturn's Stratospheric Oxygen Compounds

    NASA Astrophysics Data System (ADS)

    Romani, Paul N.; Delgado Díaz, Héctor E.; Bjoraker, Gordon; Hesman, Brigette; Achterberg, Richard

    2016-10-01

    There are three known oxygenated species present in Saturn's upper atmosphere: H2O, CO and CO2. The ultimate source of the water must be external to Saturn as Saturn's cold tropopause effectively prevents any internal water from reaching the upper atmosphere. The carbon monoxide and dioxide source(s) could be internal, external, produced by the photochemical interaction of water with Saturn's stratospheric hydrocarbons or some combination of all of these. At this point it is not clear what the external source(s) are.Cassini's Composite InfraRed Spectrometer (CIRS) has detected emission lines of H2O and CO2 (Hesman et al., DPS 2015, 311.16 & Abbas et al. 2013, Ap. J. doi:10.1088/0004-637X/776/2/73) on Saturn. CIRS also retrieves the temperature of the stratosphere using CH4 lines at 7.7 microns. Using CIRS retrieved temperatures, the mole fraction of H2O at the 0.5-5 mbar level can be retrieved and the CO2 mole fraction at ~1-10 mbar. Coupled with ground based observations of CO (Cavalié et al., 2010, A&A, DOI: 10.1051/0004-6361/200912909) these observations provide a complete oxygen compound data set to test photochemical models.Preliminary results will be presented with an emphasis on upper limit analysis to determine the percentage of stratospheric CO and CO2 that can be produced photochemically from CIRS observational constraints on the H2O profile.

  18. OXYGEN TRANSPORT CERAMIC MEMBRANES

    SciTech Connect

    Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

    2001-12-01

    Conversion of natural gas to liquid fuels and chemicals is a major goal for the Nation as it enters the 21st Century. Technically robust and economically viable processes are needed to capture the value of the vast reserves of natural gas on Alaska's North Slope, and wean the Nation from dependence on foreign petroleum sources. Technologies that are emerging to fulfill this need are all based syngas as an intermediate. Syngas (a mixture of hydrogen and carbon monoxide) is a fundamental building block from which chemicals and fuels can be derived. Lower cost syngas translates directly into more cost-competitive fuels and chemicals. The currently practiced commercial technology for making syngas is either steam methane reforming (SMR) or a two-step process involving cryogenic oxygen separation followed by natural gas partial oxidation (POX). These high-energy, capital-intensive processes do not always produce syngas at a cost that makes its derivatives competitive with current petroleum-based fuels and chemicals. This project has the following 6 main tasks: Task 1--Design, fabricate and evaluate ceramic to metal seals based on graded ceramic powder/metal braze joints. Task 2--Evaluate the effect of defect configuration on ceramic membrane conductivity and long term chemical and structural stability. Task 3--Determine materials mechanical properties under conditions of high temperatures and reactive atmospheres. Task 4--Evaluate phase stability and thermal expansion of candidate perovskite membranes and develop techniques to support these materials on porous metal structures. Task 5--Assess the microstructure of membrane materials to evaluate the effects of vacancy-impurity association, defect clusters, and vacancy-dopant association on the membrane performance and stability. Task 6--Measure kinetics of oxygen uptake and transport in ceramic membrane materials under commercially relevant conditions using isotope labeling techniques.

  19. Sediment oxygen demand in eastern Kansas streams, 2014 and 2015

    USGS Publications Warehouse

    Foster, Guy M.; King, Lindsey R.; Graham, Jennifer L.

    2016-08-29

    Dissolved oxygen concentrations in streams are affected by physical, chemical, and biological factors in the water column and streambed, and are an important factor for the survival of aquatic organisms. Sediment oxygen demand (SOD) rates in Kansas streams are not well understood. During 2014 and 2015, the U.S. Geological Survey, in cooperation with the Kansas Department of Health and Environment, measured SOD at eight stream sites in eastern Kansas to quantify SOD rates and variability with respect to season, land use, and bottom-sediment characteristics. Sediment oxygen demand rates (SODT) ranged from 0.01 to 3.15 grams per square meter per day at the ambient temperature of the measurements. The summer mean SOD rate was 3.0-times larger than the late fall mean rate, likely because of increased biological activity at warm water temperatures. Given the substantial amount of variability in SOD rates possible within sites, heterogeneity of substrate type is an important consideration when designing SOD studies and interpreting the results. Sediment oxygen demand in eastern Kansas streams was correlated with land use and streambed-sediment characteristics, though the strength of relations varied seasonally. The small number of study sites precluded a more detailed analysis. The effect of basin land use and streambed sediment characteristics on SOD is currently (2016) not well understood, and there may be many contributing factors including basin influences on water quality that affect biogeochemical cycles and the biological communities supported by the stream.

  20. Oxygen-reducing catalyst layer

    DOEpatents

    O'Brien, Dennis P [Maplewood, MN; Schmoeckel, Alison K [Stillwater, MN; Vernstrom, George D [Cottage Grove, MN; Atanasoski, Radoslav [Edina, MN; Wood, Thomas E [Stillwater, MN; Yang, Ruizhi [Halifax, CA; Easton, E Bradley [Halifax, CA; Dahn, Jeffrey R [Hubley, CA; O'Neill, David G [Lake Elmo, MN

    2011-03-22

    An oxygen-reducing catalyst layer, and a method of making the oxygen-reducing catalyst layer, where the oxygen-reducing catalyst layer includes a catalytic material film disposed on a substrate with the use of physical vapor deposition and thermal treatment. The catalytic material film includes a transition metal that is substantially free of platinum. At least one of the physical vapor deposition and the thermal treatment is performed in a processing environment comprising a nitrogen-containing gas.

  1. Simulating Biological and Non-Biological Motion

    ERIC Educational Resources Information Center

    Bruzzo, Angela; Gesierich, Benno; Wohlschlager, Andreas

    2008-01-01

    It is widely accepted that the brain processes biological and non-biological movements in distinct neural circuits. Biological motion, in contrast to non-biological motion, refers to active movements of living beings. Aim of our experiment was to investigate the mechanisms underlying mental simulation of these two movement types. Subjects had to…

  2. Hot oxygen corona of Mars

    SciTech Connect

    Ip, W.H.

    1988-10-01

    Electron dissociative recombination of O2(+) ions in the Venus ionosphere, which may be an important source of suprathermal atomic oxygen, is presently considered as a factor in the Mars exosphere; due to the weaker surface gravitational attraction of Mars, a hot oxygen corona thus formed would be denser than that of Venus at altitudes greater than 2000 km despite Mars' lower ionospheric content. If such an extended oxygen corona does exist on Mars, its collisional interaction with Phobos would lead to the formation of an oxygen gas torus whose average number density is of the order of only 1-2/cu cm along the Phobos orbit. 51 references.

  3. Mechanisms of Oxidation with Oxygen

    PubMed Central

    Taube, Henry

    1965-01-01

    Several topics are dealt with in discussing the reactions of molecular oxygen, but a common goal is pursued in each: to try to understand the reactions in terms of the fundamental properties of the oxygen molecule, and of the other reactants. The paper first describes the electronic structure of oxygen and of two low-lying electronically excited states. Concern with the low-lying electronically excited states is no longer the sole property of spectroscopists; recently, evidence has been presented for the participation of such activated molecules in chemical reactions. The chemistry of oxygen is dominated by the fact that the molecule in the ground state has two unpaired electrons, whereas the products of oxidation in many important reactions have zero spin. In its reactions with transition metal ions the restrictions imposed by the spin state of the oxygen molecule are easily circumvented. A number of reactions of oxygen with metal ions have been studied in considerable detail; conclusions on basic aspects of the reaction mechanism are outlined. Among the most interesting reactions of oxygen are those in which it is reversibly absorbed by reducing agents. Reversible absorption to form a peroxide in the bound state is possible; some of the conditions which must be fulfilled by a reducing system to qualify as storing oxygen in this way are reasonably well understood and are here enunciated. Little has been done on the formation of oxygen from water; some factors involved in this process are discussed. PMID:5859925

  4. Retinal oxygen extraction in humans

    NASA Astrophysics Data System (ADS)

    Werkmeister, René M.; Schmidl, Doreen; Aschinger, Gerold; Doblhoff-Dier, Veronika; Palkovits, Stefan; Wirth, Magdalena; Garhöfer, Gerhard; Linsenmeier, Robert A.; Leitgeb, Rainer A.; Schmetterer, Leopold

    2015-10-01

    Adequate function of the retina is dependent on proper oxygen supply. In humans, the inner retina is oxygenated via the retinal circulation. We present a method to calculate total retinal oxygen extraction based on measurement of total retinal blood flow using dual-beam bidirectional Doppler optical coherence tomography and measurement of oxygen saturation by spectrophotometry. These measurements were done on 8 healthy subjects while breathing ambient room air and 100% oxygen. Total retinal blood flow was 44.3 ± 9.0 μl/min during baseline and decreased to 18.7 ± 4.2 μl/min during 100% oxygen breathing (P < 0.001) resulting in a pronounced decrease in retinal oxygen extraction from 2.33 ± 0.51 μl(O2)/min to 0.88 ± 0.14 μl(O2)/min during breathing of 100% oxygen. The method presented in this paper may have significant potential to study oxygen metabolism in hypoxic retinal diseases such as diabetic retinopathy.

  5. Retinal oxygen extraction in humans

    PubMed Central

    Werkmeister, René M.; Schmidl, Doreen; Aschinger, Gerold; Doblhoff-Dier, Veronika; Palkovits, Stefan; Wirth, Magdalena; Garhöfer, Gerhard; Linsenmeier, Robert A.; Leitgeb, Rainer A.; Schmetterer, Leopold

    2015-01-01

    Adequate function of the retina is dependent on proper oxygen supply. In humans, the inner retina is oxygenated via the retinal circulation. We present a method to calculate total retinal oxygen extraction based on measurement of total retinal blood flow using dual-beam bidirectional Doppler optical coherence tomography and measurement of oxygen saturation by spectrophotometry. These measurements were done on 8 healthy subjects while breathing ambient room air and 100% oxygen. Total retinal blood flow was 44.3 ± 9.0 μl/min during baseline and decreased to 18.7 ± 4.2 μl/min during 100% oxygen breathing (P < 0.001) resulting in a pronounced decrease in retinal oxygen extraction from 2.33 ± 0.51 μl(O2)/min to 0.88 ± 0.14 μl(O2)/min during breathing of 100% oxygen. The method presented in this paper may have significant potential to study oxygen metabolism in hypoxic retinal diseases such as diabetic retinopathy. PMID:26503332

  6. Effects of pH amendment on metal working fluid wastewater biological treatment using a defined bacterial consortium.

    PubMed

    van der Gast, Christopher J; Thompson, Ian P

    2005-02-05

    The aim of this study was to determine whether pH amendment of a highly alkaline metal working fluid (MWF) wastewater would improve biological treatment in a bioreactor system following introduction of a bacterial inoculum (comprised of the following strains: Agrobacterium radiobacter, Comamonas testosteroni, Methylobacterium mesophilicum, Microbacterium esteraromaticum, and Microbacterium saperdae). The pH values tested were 6, 7, 8, and 9. Three replicate batch mode bioreactors inoculated with the bacterial inoculum (plus an abiotic control bioreactor) were operated for each of the four pH conditions. After 14 days, the final mean chemical oxygen demand (COD) reduction at pH 9 was 50 +/- 1.4%; at pH 8, 58 +/- 1.4%; pH 7, 65 +/- 1.0%; and pH 6, 75 +/- 2.7% of the initial COD (approximately 10,000 mg L(-1)), respectively. Interestingly, within 5 days, the pH in all inoculated bioreactors progressed toward pH 8. However, all abiotic control bioreactors remained at the pH at which they were amended. The fate of the inoculum, determined by denaturing gradient gel electrophoresis (DGGE) and by cluster analysis of the resulting DGGE profiles, revealed that the inocula survived throughout operation of all pH-amended bioreactors. Length-heterogeneity polymerase chain reaction (PCR) was used to track the population dynamics of individual strains. After 7 days of operation, M. esteraromaticum was the most abundant population in all bioreactors, regardless of pH. From our findings, it appears necessary to adjust the MWF wastewater from pH 9 to between 6 and 7, to achieve optimal biological treatment rates.

  7. Oxygen Transport Ceramic Membranes

    SciTech Connect

    S. Bandopadhyay; N. Nagabhushana; X.-D Zhou; Q. Cai; J. Yang; W.B. Yelon; W.J. James; H.U. Anderson; Alan Jacobson; C.A. Mims

    2004-10-01

    The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. In this report, Moessbauer spectroscopy was used to study the local environmentals of LSFT with various level of oxygen deficiency. Ionic valence state, magnetic interaction and influence of Ti on superexchange are discussed Stable crack growth studies on Dense OTM bars provided by Praxair were done at elevated temperature, pressure and elevated conditions. Post-fracture X-ray data of the OTM fractured at 1000 C in environment were refined by FullProf code and results indicate a distortion of the parent cubic perovskite to orthorhombic structure with reduced symmetry. TGA-DTA studies on the post-fracture samples also indicated residual effect arising from the thermal and stress history of the samples. An electrochemical cell has been designed and built for measurements of the Seebeck coefficient as a function of temperature and pressure. The initial measurements on La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} are reported. Neutron diffraction measurements of the same composition are in agreement with both the stoichiometry and the kinetic behavior observed in coulometric titration measurements. A series of isotope transients under air separation mode (small gradient) were completed on the membrane of LSCrF-2828 at 900 C. Low pO{sub 2} atmospheres based on with CO-CO{sub 2} mixtures have also been admitted to the delivery side of the LSCrF-2828 membrane to produce the gradients which exist under syngas generation conditions. The COCO{sub 2} mixtures have normal isotopic {sup 18}O abundances. The evolution of {sup 18}O on the delivery side in these experiments after an {sup 18}O pulse on the air side reveals a wealth of information about the oxygen transport processes.

  8. Rhizosphere anode model explains high oxygen levels during operation of a Glyceria maxima PMFC.

    PubMed

    Timmers, Ruud A; Strik, David P B T B; Arampatzoglou, Cristina; Buisman, Cees J N; Hamelers, Hubertus V M

    2012-03-01

    In this paper, the effect of root oxygen loss on energy recovery of the plant microbial fuel cell (PMFC) is described. In this manner, advanced understanding of competing processes within the rhizosphere-anode interface was provided. A microscopic model was developed on the basis of exudation, oxygen loss, biological oxidation, and biological current generation. The model was successfully validated by comparison to oxygen concentration profiles, volatile fatty acid profiles, and chemical oxygen demand profiles measured in the anode compartment. The model predicted oxic zones around roots in the anode of the plant microbial fuel cell. Results show no direct link between current generation and photosynthesis. This was consistent with the model which predicted that current was generated via hydrolysis of root-derived organic compounds. This result means that to optimize energy recovery of a PMFC, the plant selection should focus on high root biomass production combined with low oxygen loss.

  9. Do submesoscale frontal processes ventilate the oxygen minimum zone off Peru?

    NASA Astrophysics Data System (ADS)

    Thomsen, S.; Kanzow, T.; Colas, F.; Echevin, V.; Krahmann, G.; Engel, A.

    2016-08-01

    The Peruvian upwelling system encompasses the most intense and shallowest oxygen minimum zone (OMZ) in the ocean. This system shows pronounced submesoscale activity like filaments and fronts. We carried out glider-based observations off Peru during austral summer 2013 to investigate whether submesoscale frontal processes ventilate the Peruvian OMZ. We present observational evidence for the subduction of highly oxygenated surface water in a submesoscale cold filament. The subduction event ventilates the oxycline but does not reach OMZ core waters. In a regional submesoscale-permitting model we study the pathways of newly upwelled water. About 50% of upwelled virtual floats are subducted below the mixed layer within 5 days emphasizing a hitherto unrecognized importance of subduction for the ventilation of the Peruvian oxycline.

  10. Mars oxygen production system design

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

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

  11. Environmental science: Oceans lose oxygen

    NASA Astrophysics Data System (ADS)

    Gilbert, Denis

    2017-02-01

    Oxygen is essential to most life in the ocean. An analysis shows that oxygen levels have declined by 2% in the global ocean over the past five decades, probably causing habitat loss for many fish and invertebrate species. See Letter p.335

  12. ANALYTICAL METHODS FOR FUEL OXYGENATES

    EPA Science Inventory

    MTBE (and potentially any other oxygenate) may be present at any petroleum UST site, whether the release is new or old, virtually anywhere in the United States. Consequently, it is prudent to analyze samples for the entire suite of oxygenates as identified in this protocol (i.e....

  13. The oxygen therapy.

    PubMed

    Corsonello, A; Pedone, C; Scarlata, S; Zito, A; Laino, I; Antonelli-Incalzi, R

    2013-01-01

    Oxygen (O(2)) is a vital element. Shortage of O(2) results in deranged metabolism and important changes in vascular tone with opposite effects on the systemic and pulmonary circulation. During hypoxemia, oxidative stress exposes the organism to a sort of accelerated senescence as well as to several acute untoward effects. Thus, hypoxemia should be promptly recognized and treated, hopefully by measures tailored to the pathophysiological mechanisms underlying hypoxemia. However, O(2) therapy remains the most common therapy of hypoxemia, but it must be carefully tailored to relieve hypoxemia without provoking hyperoxia or hypercarbia. Then, the individual response to O(2) as well as changing needs of O(2) during sleep or exercise must be evaluated to provide the best O(2) therapy. Hyperoxia, the effect of overcorrection of hypoxia, can dramatically impact the health status and threaten the survival of the newborn and, through different mechanisms and effects, the adult. A thorough knowledge of the pathophysiological bases of hypoxemia and O(2) storage and delivery devices is then mandatory to administer O(2) therapy guaranteeing for optimal correction of hypoxemia and minimizing the risk of hyperoxia. Consistent with this aim also is a careful scrutiny of instruments and procedures for monitoring the individual response to O(2) over time. Thus, at variance from classical pharmacological therapy, performing O(2) therapy requires a vast array of clinical and technical competences. The optimal integration of these competences is needed to optimize O(2) therapy on individual bases.

  14. OXYGEN TRANSPORT CERAMIC MEMBRANES

    SciTech Connect

    Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

    2002-01-01

    Conversion of natural gas to liquid fuels and chemicals is a major goal for the Nation as it enters the 21st Century. Technically robust and economically viable processes are needed to capture the value of the vast reserves of natural gas on Alaska's North Slope, and wean the Nation from dependence on foreign petroleum sources. Technologies that are emerging to fulfill this need are all based syngas as an intermediate. Syngas (a mixture of hydrogen and carbon monoxide) is a fundamental building block from which chemicals and fuels can be derived. Lower cost syngas translates directly into more cost-competitive fuels and chemicals. The currently practiced commercial technology for making syngas is either steam methane reforming (SMR) or a two-step process involving cryogenic oxygen separation followed by natural gas partial oxidation (POX). These high-energy, capital-intensive processes do not always produce syngas at a cost that makes its derivatives competitive with current petroleum-based fuels and chemicals.

  15. The maximum oxygen intake*

    PubMed Central

    Shephard, Roy J.; Allen, C.; Benade, A. J. S.; Davies, C. T. M.; di Prampero, P. E.; Hedman, R.; Merriman, J. E.; Myhre, K.; Simmons, R.

    1968-01-01

    Lack of cardiorespiratory fitness may well contribute to the increasing prevalence of degenerative cardiovascular disease throughout the world. As a first step towards co-ordinated and internationally comparable investigation of this problem, methods of measuring the reference standard of cardiorespiratory fitness—the maximum oxygen intake, (V̇o2)max—were compared by an international working party that met in Toronto in the summer of 1967. Repeated testing of 24 subjects showed that the (V̇o2)max was greatest on the treadmill, 3.4% smaller in a stepping test, and 6.6% smaller during use of a bicycle ergometer. There were also parallel differences in cardiac stroke volume. Uphill treadmill running was recommended for the laboratory measurement of (V̇o2)max, and stepping or bicycle exercise for field studies. A discontinuous series of maximum tests caused some improvement in the fitness of subjects, and a “continuous” test (with small increases in load at 2-min intervals) was preferred. PMID:5303329

  16. The Oxygen a Band

    NASA Astrophysics Data System (ADS)

    Benner, D. Chris; Devi, V. Malathy; Hoo, Jiajun; Hodges, Joseph; Long, David A.; Sung, Keeyoon; Drouin, Brian; Okumura, Mitchio; Bui, Thinh Quoc; Rupasinghe, Priyanka

    2014-06-01

    The oxygen A band is used for numerous atmospheric experiments, but spectral line parameters that sufficiently describe the spectrum to the level required by OCO2 and other high precision/accuracy experiments are lacking. Fourier transform spectra from the Jet Propulsion Laboratory and cavity ring down spectra from the National Institute of Standards and Technology were fitted simultaneously using the William and Mary multispectrum nonlinear least squares fitting technique into a single solution including the entire band. In addition, photoacoustic spectra already available from the California Institute of Technology will be added to the solution. The three types of spectrometers are complementary allowing the strengths of each to fill in the weaknesses of the others. With this technique line positions, intensities, widths, shifts, line mixing, Dicke narrowing, temperature dependences and collision induced absorption have been obtained in a single physically consistent fit. D. Chris Benner, C. P. Rinsland, V. M. Devi, M. A. H. Smith, and D. Atkins, JQSRT 1995;53:705-21. Part of the research described in this paper was performed at The College of William and Mary, the, Jet Propulsion Laboratory, California Institute of Technology, under contracts and cooperative agreements with the National Aeronautics and Space Administration and the Jet Propulsion Laboratory. Support for the National Institute of Standards and Technology was provided by the NIST Greenhouse Gas Measurements and Climate Research Program and a NIST Innovations in Measurement Science (IMS) award.

  17. Oxygen Transport Ceramic Membranes

    SciTech Connect

    S. Bandopadhyay; N. Nagabhushana; X.-D Zhou; W.B. Yelon; H.U. Anderson; Alan Jacobson; C.A. Mims

    2004-02-01

    The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and initial studies on newer composition of Ti doped LSF. Dense OTM bars provided by Praxair were loaded to fracture at varying stress rates. Studies were done at room temperature in air and at 1000 C in a specified environment to evaluate slow crack growth behavior. In addition, studies were also begun to obtain reliable estimates of fracture toughness and stable crack growth in specific environments. Newer composition of Ti doped LSF membranes were characterized by neutron diffraction analysis. Quench studies indicated an apparent correlation between the unit cell volume and oxygen occupancy. The studies however, indicated an anomaly of increasing Fe/Ti ratio with change in heat treatment. Ti doped LSF was also characterized for stoichiometry as a function of temp and pO{sub 2}. The non stoichiometry parameter {delta} was observed to increase almost linearly on lowering pO{sub 2} until a ideal stoichiometric composition of {delta} = 0.175 was approached.

  18. Ocean oxygenation in the wake of the Marinoan glaciation.

    PubMed

    Sahoo, Swapan K; Planavsky, Noah J; Kendall, Brian; Wang, Xinqiang; Shi, Xiaoying; Scott, Clint; Anbar, Ariel D; Lyons, Timothy W; Jiang, Ganqing

    2012-09-27

    Metazoans are likely to have their roots in the Cryogenian period, but there is a marked increase in the appearance of novel animal and algae fossils shortly after the termination of the late Cryogenian (Marinoan) glaciation about 635 million years ago. It has been suggested that an oxygenation event in the wake of the severe Marinoan glaciation was the driving factor behind this early diversification of metazoans and the shift in ecosystem complexity. But there is little evidence for an increase in oceanic or atmospheric oxygen following the Marinoan glaciation, or for a direct link between early animal evolution and redox conditions in general. Models linking trends in early biological evolution to shifts in Earth system processes thus remain controversial. Here we report geochemical data from early Ediacaran organic-rich black shales (∼635-630 million years old) of the basal Doushantuo Formation in South China. High enrichments of molybdenum and vanadium and low pyrite sulphur isotope values (Δ(34)S values ≥65 per mil) in these shales record expansion of the oceanic inventory of redox-sensitive metals and the growth of the marine sulphate reservoir in response to a widely oxygenated ocean. The data provide evidence for an early Ediacaran oxygenation event, which pre-dates the previous estimates for post-Marinoan oxygenation by more than 50 million years. Our findings seem to support a link between the most severe glaciations in Earth's history, the oxygenation of the Earth's surface environments, and the earliest diversification of animals.

  19. Research on rechargeable oxygen electrodes

    NASA Technical Reports Server (NTRS)

    Giner, J.; Malachesky, P. A.; Holleck, G.

    1971-01-01

    Studies were carried out on a number of factors which may influence the behavior of the platinum electrocatalyst of oxygen electrodes for use in rechargeable metal-oxygen batteries or hydrogen-oxygen fuel cells. The effects of pretreatments for various potentials and added ionic species, which could be present in such systems, were studied with reguard to: (1) the state of surface oxidation, (2) platinum dissolution, (3) the kinetics of oxygen evolution and reduction (including the role of hydrogen peroxide), and (4) changes in porous electrode structure. These studies were carried out on smooth platinum, platinized platinum, and Teflon-bonded platinum black electrodes in carefully purified electrolyte solutions. The main factors which appear to affect rechargeable oxygen electrode performance and life are: (1) the buildup of a refractory anodic layer on extended cycling, and (2) the dissolution of platinum.

  20. Oxygen detection using evanescent fields

    DOEpatents

    Duan, Yixiang; Cao, Weenqing

    2007-08-28

    An apparatus and method for the detection of oxygen using optical fiber based evanescent light absorption. Methylene blue was immobilized using a sol-gel process on a portion of the exterior surface of an optical fiber for which the cladding has been removed, thereby forming an optical oxygen sensor. When light is directed through the optical fiber, transmitted light intensity varies as a result of changes in the absorption of evanescent light by the methylene blue in response to the oxygen concentration to which the sensor is exposed. The sensor was found to have a linear response to oxygen concentration on a semi-logarithmic scale within the oxygen concentration range between 0.6% and 20.9%, a response time and a recovery time of about 3 s, ant to exhibit good reversibility and repeatability. An increase in temperature from 21.degree. C. to 35.degree. C. does not affect the net absorption of the sensor.

  1. Involvement of Cytochrome P450 in Reactive Oxygen Species Formation and Cancer.

    PubMed

    Hrycay, Eugene G; Bandiera, Stelvio M

    2015-01-01

    This review examines the involvement of cytochrome P450 (CYP) enzymes in the formation of reactive oxygen species in biological systems and discusses the possible involvement of reactive oxygen species and CYP enzymes in cancer. Reactive oxygen species are formed in biological systems as byproducts of the reduction of molecular oxygen and include the superoxide radical anion (∙O2-), hydrogen peroxide (H2O2), hydroxyl radical (∙OH), hydroperoxyl radical (HOO∙), singlet oxygen ((1)O2), and peroxyl radical (ROO∙). Two endogenous sources of reactive oxygen species are the mammalian CYP-dependent microsomal electron transport system and the mitochondrial electron transport chain. CYP enzymes catalyze the oxygenation of an organic substrate and the simultaneous reduction of molecular oxygen. If the transfer of oxygen to a substrate is not tightly controlled, uncoupling occurs and leads to the formation of reactive oxygen species. Reactive oxygen species are capable of causing oxidative damage to cellular membranes and macromolecules that can lead to the development of human diseases such as cancer. In normal cells, intracellular levels of reactive oxygen species are maintained in balance with intracellular biochemical antioxidants to prevent cellular damage. Oxidative stress occurs when this critical balance is disrupted. Topics covered in this review include the role of reactive oxygen species in intracellular cell signaling and the relationship between CYP enzymes and cancer. Outlines of CYP expression in neoplastic tissues, CYP enzyme polymorphism and cancer risk, CYP enzymes in cancer therapy and the metabolic activation of chemical procarcinogens by CYP enzymes are also provided.

  2. Biological upgrading of coal liquids

    SciTech Connect

    Not Available

    1992-01-01

    The objective of this project is to develop a simple biological process for the removal of nitrogen, oxygen, and sulfur heteroatoms from coal liquids, and simultaneously reducing aromaticity. Microorganisms, employing biocatalysts, are known to degrade aromatic heteroatom compounds in nature to NH[sub 3], SO[sub 4], and CO[sub 2]. Preliminary experiments in the ERI laboratories to determine the feasibility of biological removal of N, 0, and S from coal and shale oil liquids have shown up to 20 percent nitrogen removal, 40 percent sulfur removal, and 100 percent oxygen removal in a simple one stage incubation. This project will screen known bacteria and develop isolates for N, 0, and S removal and aromaticity reduction. The performance of the best of these cultures will be optimized for complete heteroatom removal in a single step go up. An outline of the protocol used to select pure cultures and isolates for their suitability in degrading heteroatom compounds is presented. Also shown is a listing of nine model compounds to be used in culture comparison and selection studies. Preliminary results with isolate ERI4 shows that the bacterium grows on phenol as its sole carbon source and rapidly depletes the compound from the medium. Similar results are shown for ERI5, which grows on pyridine as its sole carbon and nitrogen source and rapidly removes the compound from the medium.

  3. Systems Biology of the Microvasculature

    PubMed Central

    Clegg, Lindsay E.; Mac Gabhann, Feilim

    2015-01-01

    The vascular network carries blood throughout the body, delivering oxygen to tissues and providing a pathway for communication between distant organs. The network is hierarchical and structured, but also dynamic, especially at the smaller scales. Remodeling of the microvasculature occurs in response to local changes in oxygen, gene expression, cell-cell communication, and chemical and mechanical stimuli from the microenvironment. These local changes occur as a result of physiological processes such as growth and exercise, as well as acute and chronic diseases including stroke, cancer, and diabetes, and pharmacological intervention. While the vasculature is an important therapeutic target in many diseases, drugs designed to inhibit vascular growth have achieved only limited success, and no drug has yet been approved to promote therapeutic vascular remodeling. This highlights the challenges involved in identifying appropriate therapeutic targets in a system as complex as the vasculature. Systems biology approaches provide a means to bridge current understanding of the vascular system, from detailed signaling dynamics measured in vitro and pre-clinical animal models of vascular disease, to a more complete picture of vascular regulation in vivo. This will translate to an improved ability to identify multi-component biomarkers for diagnosis, prognosis, and monitoring of therapy that are easy to measure in vivo, as well as better drug targets for specific disease states. In this review, we summarize systems biology approaches that have advanced our understanding of vascular function and dysfunction in vivo, with a focus on computational modeling. PMID:25839068

  4. Cell death induced by direct laser activation of singlet oxygen at 1270 nm

    NASA Astrophysics Data System (ADS)

    Anquez, F.; El Yazidi Belkoura, I.; Suret, P.; Randoux, S.; Courtade, E.

    2013-02-01

    Singlet oxygen plays a major role in many chemical and biological photo-oxidation processes. It has a high chemical reactivity, which is commonly harnessed for therapeutic issues. Indeed, singlet oxygen is recognized as the major cytotoxic agent in photodynamic therapy. In this treatment of cancer, singlet oxygen is created, among other reactive species, by an indirect transfer of energy from light to molecular oxygen via excitation of a photosensitizer. In this paper, we show that the conventional singlet oxygen production scheme can be simplified. Production of singlet oxygen is achieved in living cells from photosensitizer-free 1270 nm laser excitation of the electronic ground state of molecular oxygen. The quantity of singlet oxygen produced in this way is sufficient to induce an oxidative stress leading to cell death. Other effects such as thermal stress are discriminated, and we conclude that cell death is only due to singlet oxygen creation. This new simplified scheme of singlet oxygen activation can be seen as a breakthrough for phototherapies of malignant diseases and/or as a non-invasive possibility to generate reactive oxygen species in a tightly controlled manner.

  5. Real-Time Monitoring of Singlet Oxygen and Oxygen Partial Pressure During the Deep Photodynamic Therapy In Vitro.

    PubMed

    Li, Weitao; Huang, Dong; Zhang, Yan; Liu, Yangyang; Gu, Yueqing; Qian, Zhiyu

    2016-09-01

    Photodynamic therapy (PDT) is an effective noninvasive method for the tumor treatment. The major challenge in current PDT research is how to quantitatively evaluate therapy effects. To our best knowledge, this is the first time to combine multi-parameter detection methods in PDT. More specifically, we have developed a set of system, including the high-sensitivity measurement of singlet oxygen, oxygen partial pressure and fluorescence image. In this paper, the detection ability of the system was validated by the different concentrations of carbon quantum dots. Moreover, the correlation between singlet oxygen and oxygen partial pressure with laser irradiation was observed. Then, the system could detect the signal up to 0.5 cm tissue depth with 660 nm irradiation and 1 cm tissue depth with 980 nm irradiation by using up-conversion nanoparticles during PDT in vitro. Furthermore, we obtained the relationship among concentration of singlet oxygen, oxygen partial pressure and tumor cell viability under certain conditions. The results indicate that the multi-parameter detection system is a promising asset to evaluate the deep tumor therapy during PDT. Moreover, the system might be potentially used for the further study in biology and molecular imaging.

  6. Insensitivity of cerebral oxygen transport to oxygen affinity of hemoglobin-based oxygen carriers

    PubMed Central

    Koehler, Raymond C.; Fronticelli, Clara; Bucci, Enrico

    2008-01-01

    The cerebrovascular effects of exchange transfusion of various cell-free hemoglobins that possess different oxygen affinities are reviewed. Reducing hematocrit by transfusion of a non-oxygen-carrying solution dilates pial arterioles on the brain surface and increases cerebral blood flow to maintain a constant bulk oxygen transport to the brain. In contrast, transfusion of hemoglobins with P50 of 4–34 Torr causes constriction of pial arterioles that offsets the decrease in blood viscosity to maintain cerebral blood flow and oxygen transport. The autoregulatory constriction is dependent on synthesis of 20-HETE from arachidonic acid. This oxygen-dependent reaction is apparently enhanced by facilitated oxygen diffusion from the red cell to the endothelium arising from increased plasma oxygen solubility in the presence of low or high-affinity hemoglobin. Exchange transfusion of recombinant hemoglobin polymers with P50 of 3 and 18 Torr reduces infarct volume from experimental stroke. Cell-free hemoglobins do not require a P50 as high as red blood cell hemoglobin to facilitate oxygen delivery. PMID:18230370

  7. Oxygen Transport Ceramic Membranes

    SciTech Connect

    S. Bandopadhyay; T. Nithyanantham; X.-D Zhou; Y-W. Sin; H.U. Anderson; Alan Jacobson; C.A. Mims

    2005-11-01

    The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. In the current research, the electrical conductivity and Seebeck coefficient were measured as a function of temperature in air. Based on these measurements, the charge carrier concentration, net acceptor dopant concentration, activation energy of conduction and mobility were estimated. The studies on the fracture toughness of the LSFT and dual phase membranes at room temperature have been completed and reported previously. The membranes that are exposed to high temperatures at an inert and a reactive atmosphere undergo many structural and chemical changes which affects the mechanical properties. To study the effect of temperature on the membranes when exposed to an inert environment, the membranes (LAFT and Dual phase) were heat treated at 1000 C in air and N{sub 2} atmosphere and hardness and fracture toughness of the membranes were studied after the treatment. The indentation method was used to find the fracture toughness and the effect of the heat treatment on the mechanical properties of the membranes. Further results on the investigation of the origin of the slow kinetics on reduction of ferrites have been obtained. The slow kinetics appears to be related to a non-equilibrium reduction pathway that initially results in the formation of iron particles. At long times, equilibrium can be reestablished with recovery of the perovskite phase. 2-D modeling of oxygen movement has been undertaken in order to fit isotope data. The model will serve to study ''frozen'' profiles in patterned or composite membranes.

  8. Monitoring Cerebral Oxygenation in Neonates: An Update

    PubMed Central

    Dix, Laura Marie Louise; van Bel, Frank; Lemmers, Petra Maria Anna

    2017-01-01

    Cerebral oxygenation is not always reflected by systemic arterial oxygenation. Therefore, regional cerebral oxygen saturation (rScO2) monitoring with near-infrared spectroscopy (NIRS) is of added value in neonatal intensive care. rScO2 represents oxygen supply to the brain, while cerebral fractional tissue oxygen extraction, which is the ratio between rScO2 and systemic arterial oxygen saturation, reflects cerebral oxygen utilization. The balance between oxygen supply and utilization provides insight in neonatal cerebral (patho-)physiology. This review highlights the potential and limitations of cerebral oxygenation monitoring with NIRS in the neonatal intensive care unit. PMID:28352624

  9. Oxygenates vs. synthesis gas

    SciTech Connect

    Kamil Klier; Richard G. Herman; Alessandra Beretta; Maria A. Burcham; Qun Sun; Yeping Cai; Biswanath Roy

    1999-04-01

    Methanol synthesis from H{sub 2}/CO has been carried out at 7.6 MPa over zirconia-supported copper catalysts. Catalysts with nominal compositions of 10/90 mol% and 30/70 mol% Cu/ZrO{sub 2} were used in this study. Additionally, a 3 mol% cesium-doped 10/90 catalyst was prepared to study the effect of doping with heavy alkali, and this promoter greatly increased the methanol productivity. The effects of CO{sub 2} addition, water injection, reaction temperature, and H{sub 2}/C0 ratio have been investigated. Both CO{sub 2} addition to the synthesis gas and cesium doping of the catalyst promoted methanol synthesis, while inhibiting the synthesis of dimethyl ether. Injection of water, however, was found to slightly suppress methanol and dimethyl ether formation while being converted to CO{sub 2} via the water gas shift reaction over these catalysts. There was no clear correlation between copper surface area and catalyst activity. Surface analysis of the tested samples revealed that copper tended to migrate and enrich the catalyst surface. The concept of employing a double-bed reactor with a pronounced temperature gradient to enhance higher alcohol synthesis was explored, and it was found that utilization of a Cs-promoted Cu/ZnO/Cr{sub 2}O{sub 3} catalyst as a first lower temperature bed and a Cs-promoted ZnO/Cr{sub 2}O{sub 3} catalyst as a second high-temperature bed significantly promoted the productivity of 2-methyl-1-propanol (isobutanol) from H{sub 2}/CO synthesis gas mixtures. While the conversion of CO to C{sub 2+} oxygenates over the double-bed configuration was comparable to that observed over the single Cu-based catalyst, major changes in the product distribution occurred by the coupling to the zinc chromite catalyst; that is, the productivity of the C{sub 1}-C{sub 3} alcohols decreased dramatically, and 2-methyl branched alcohols were selectively formed. The desirable methanol/2-methyl oxygenate molar ratios close to 1 were obtained in the present double

  10. Oceanic oxygenation events in the anoxic Ediacaran ocean.

    PubMed

    Sahoo, S K; Planavsky, N J; Jiang, G; Kendall, B; Owens, J D; Wang, X; Shi, X; Anbar, A D; Lyons, T W

    2016-09-01

    The ocean-atmosphere system is typically envisioned to have gone through a unidirectional oxygenation with significant oxygen increases in the earliest (ca. 635 Ma), middle (ca. 580 Ma), or late (ca. 560 Ma) Ediacaran Period. However, temporally discontinuous geochemical data and the patchy metazoan fossil record have been inadequate to chart the details of Ediacaran ocean oxygenation, raising fundamental debates about the timing of ocean oxygenation, its purported unidirectional rise, and its causal relationship, if any, with the evolution of early animal life. To better understand the Ediacaran ocean redox evolution, we have conducted a multi-proxy paleoredox study of a relatively continuous, deep-water section in South China that was paleogeographically connected with the open ocean. Iron speciation and pyrite morphology indicate locally euxinic (anoxic and sulfidic) environments throughout the Ediacaran in this section. In the same rocks, redox sensitive element enrichments and sulfur isotope data provide evidence for multiple oceanic oxygenation events (OOEs) in a predominantly anoxic global Ediacaran-early Cambrian ocean. This dynamic redox landscape contrasts with a recent view of a redox-static Ediacaran ocean without significant change in oxygen content. The duration of the Ediacaran OOEs may be comparable to those of the oceanic anoxic events (OAEs) in otherwise well-oxygenated Phanerozoic oceans. Anoxic events caused mass extinctions followed by fast recovery in biologically diversified Phanerozoic oceans. In contrast, oxygenation events in otherwise ecologically monotonous anoxic Ediacaran-early Cambrian oceans may have stimulated biotic innovations followed by prolonged evolutionary stasis.

  11. Oxygen saturation and cognitive performance.

    PubMed

    Andersson, Jan; Berggren, Peter; Grönkvist, Mikael; Magnusson, Staffan; Svensson, Erland

    2002-07-01

    The purpose of the experiments was to investigate how inhalation of 100% oxygen affected cognitive performance. A test battery was developed that was designed to capture different aspects of cognitive processes, i.e., perception, attention, working memory, long-term memory and prospective memory. All tests were verbally based, thus reducing cognitive spatial processes to a minimum. In experiment 1, 48 participants volunteered in a complete factorial within-participant design. Two different conditions for type of gas were used, inhalation of 100% oxygen and inhalation of breathing air (approximately 21% oxygen balanced with nitrogen). The inhalation was performed during the 1 min prior to starting each separate test. The instructions for each test were given during the inhalation period. All participants inhaled oxygen or breathing air through a Swedish military pilot mask. Physiological (heartbeats per minute and blood oxygen saturation level) reactions were recorded continuously throughout the session. Participants also completed a mood-state questionnaire before and after the test battery. The results revealed that cognitive performance were not affected by inhalation. Hence, this experiment does not replicate previous findings that suggest that inhalation of 100% oxygen could increase cognitive performance. Another experiment was performed to control for methodological issues. Experiment 2 revealed exactly the same pattern, i.e., inhalation of oxygen did not affect cognitive functioning.

  12. Oxygen acceleration in magnetotail reconnection

    NASA Astrophysics Data System (ADS)

    Liang, Haoming; Lapenta, Giovanni; Walker, Raymond J.; Schriver, David; El-Alaoui, Mostafa; Berchem, Jean

    2017-01-01

    Motivated by the observed high concentration of oxygen ions in the magnetotail during enhanced geomagnetic activity, we investigated the oxygen acceleration in magnetotail reconnection by using 2.5-D implicit particle-in-cell simulations. We found that lobe oxygen ions can enter the downstream outflow region, i.e., the outflow region downstream of the dipolarization fronts (DFs) or the reconnection jet fronts. Without entering the reconnection exhaust, they are accelerated by the Hall electric field. They can populate the downstream outflow region before the DFs arrive there. This acceleration is in addition to acceleration in the exhaust by the Hall and reconnection electric fields. Oxygen ions in the preexisting current sheet are reflected by the propagating DF creating a reflected beam with a hook shape in phase space. This feature can be applied to deduce a history of the DF speed. However, it is difficult to observe for protons because their typical thermal velocity in the plasma sheet is comparable those of the DF and the reflection speed. The oxygen ions from the lobes and the preexisting current sheet form multiple beams in the distribution function in front of the DF. By comparing oxygen concentrations of 50%, 5%, and 0% with the same current sheet thickness, we found that the DF thickness is proportional to the oxygen concentration in the preexisting current sheet. All the simulation results can be used to compare with the observations from the Magnetospheric Multiscale mission.

  13. The Oxygen Paradox, oxidative stress, and ageing.

    PubMed

    Davies, Kelvin J A

    2016-04-01

    Professor Helmut Sies is being lauded in this special issue of Archives of Biochemistry & Biophysics, on the occasion of his retirement as Editor-in-Chief. There is no doubt that Helmut has exerted an enormously positive influence on this journal, the fields of Biochemistry & Biophysics in general, and the areas of free radical and redox biology & medicine in particular. Helmut Sies' many discoveries about peroxide metabolism, glutathione, glutathione peroxidases, singlet oxygen, carotenoids in general and lycopene in particular, and flavonoids, fill the pages of his more than 600 publications. In addition, he will forever be remembered for coining the term 'oxidative stress' that is so widely used (and sometimes abused) by most of his colleagues.

  14. Physiological roles of mitochondrial reactive oxygen species.

    PubMed

    Sena, Laura A; Chandel, Navdeep S

    2012-10-26

    Historically, mitochondrial reactive oxygen species (mROS) were thought to exclusively cause cellular damage and lack a physiological function. Accumulation of ROS and oxidative damage have been linked to multiple pathologies, including neurodegenerative diseases, diabetes, cancer, and premature aging. Thus, mROS were originally envisioned as a necessary evil of oxidative metabolism, a product of an imperfect system. Yet few biological systems possess such flagrant imperfections, thanks to the persistent optimization of evolution, and it appears that oxidative metabolism is no different. More and more evidence suggests that mROS are critical for healthy cell function. In this Review, we discuss this evidence following some background on the generation and regulation of mROS.

  15. Blood oxygenation monitoring by diffuse optical tomography

    SciTech Connect

    Patachia, M; Dutu, D.C.A.; Dumitras, D.C.

    2011-01-24

    Diffuse optical tomography (DOT) makes it possible to reconstruct, in two or three dimensions, the internal structure of the biological tissues based on the distribution of the absorption coefficient and the reduced scattering coefficient, using optical measurements at multiple source - detector positions on the tissue surface. The measurement of the light intensity transmitted through the tissue can be also used to compute the haemoglobin and oxyhaemoglobin concentrations, measuring the selective absorption of the main blood chromophores by near infrared spectroscopy (NIRS). The spectral selectivity of the system and the evaluation of the blood volume and blood oxygenation (BV and OXY distributions), together with the reconstruction of the inner structure of the tissue, can improve the accuracy of early cancer diagnosis, based on the tissue angiogenesis characterisation. (application of lasers and laser-optical methods in life sciences)

  16. The Oxygen Paradox, Oxidative Stress, and Ageing

    PubMed Central

    Davies, Kelvin J. A.

    2015-01-01

    Professor Helmut Sies is being lauded in this special issue of Archives of Biochemistry & Biophysics, on the occasion of his retirement as Editor-in-Chief. There is no doubt that Helmut has exerted an enormously positive influence on this journal, the fields of Biochemistry & Biophysics in general, and the areas of free radical and redox biology & medicine in particular. Helmut Sies' many discoveries about peroxide metabolism, glutathione, glutathione peroxidases, singlet oxygen, carotenoids in general and lycopene in particular, and flavonoids, fill the pages of his more than 600 publications. In addition, he will forever be remembered for coining the term ‘oxidative stress’ that is so widely used (and sometimes abused) by most of his colleagues. PMID:27095211

  17. Probing oxygen consumption in epileptic brain slices with QDs-based FRET sensors

    NASA Astrophysics Data System (ADS)

    Zhang, Chunfeng; Ingram, Justin; Schiff, Steven; Xu, Jian; Xiao, Min

    2011-02-01

    We developed ratiometric optical oxygen sensors to probe the oxygen consumption during epileptic events in rat brain slices. The oxygen sensors consist of the sensing part of phosphorescence dyes (Platinum (II) octaethylporphine ketone) and reference part of nanocystal quantum dots (NQDs) embedded in polymer blends, with pre-designed excitation through fluorescence resonance energy transfer (FRET) from NQDs to the oxygen sensitive dyes (OSDs). The ratiometric FRET sensors with fast temporal response and excellent bio-compatibility are suitable for real time quantitative dissolved oxygen (D.O.) probes in biological microenvironment. Coating the sensors onto the micro-pipettes, we performed simultaneous oxygen probes at pyramidal and oriens layers in rat hippocampal CA1. Different spatiotemporal patterns with maximum D.O. decreases of 9.9+/-1.1 mg/L and 4.9+/-0.7 mg/L during seizure events were observed in pyramidal and oriens layers, respectively.

  18. Advanced Oxygen Systems for Aircraft (Systemes d’Oxygene Avances)

    DTIC Science & Technology

    1996-04-01

    for enhancing aircrew performance at high sustained +GZ accelerations. Finally, increasing attention has been paid over the last two decades to the...comprehensive published review of the design and performance of Advanced Oxygen Systems. It has been written principally by present and past members... performance required of Advanced Oxygen Systems and with the design and assessment of the first and later generations of these systems. The monograph

  19. Extracorporeal Membrane Oxygenation and the Kidney

    PubMed Central

    Villa, Gianluca; Katz, Nevin; Ronco, Claudio

    2015-01-01

    Background Extracorporeal membrane oxygenation (ECMO) is an effective therapy for patients with reversible cardiac and/or respiratory failure. Acute kidney injury (AKI) often occurs in patients supported with ECMO; it frequently evolves into chronic kidney damage or end-stage renal disease and is associated with a reported 4-fold increase in mortality rate. Although AKI is generally due to the hemodynamic alterations associated with the baseline disease, ECMO itself may contribute to maintaining kidney dysfunction through several mechanisms. Summary AKI may be related to conditions derived from or associated with extracorporeal therapy, leading to a reduction in renal oxygen delivery and/or to inflammatory damage. In particular, during pathological conditions requiring ECMO, the biological defense mechanisms maintaining central perfusion by a reduction of perfusion to peripheral organs (such as the kidney) have been identified as pretreatment and patient-related risk factors for AKI. Hormonal pathways are also impaired in patients supported with ECMO, leading to failures in mechanisms of renal homeostasis and worsening fluid overload. Finally, inflammatory damage, due to the primary disease, heart and lung crosstalk with the kidney or associated with extracorporeal therapy itself, may further increase the susceptibility to AKI. Renal replacement therapy can be integrated into the main extracorporeal circuit during ECMO to provide for optimal fluid management and removal of inflammatory mediators. Key Messages AKI is frequently observed in patients supported with ECMO. The pathophysiology of the associated AKI is chiefly related to a reduction in renal oxygen delivery and/or to inflammatory damage. Risk factors for AKI are associated with a patient's underlying disease and ECMO-related conditions. PMID:27194996

  20. Atomic oxygen patterning from a biomedical needle-plasma source

    SciTech Connect

    Kelly, Seán; Turner, Miles M.

    2013-09-28

    A “plasma needle” is a cold plasma source operating at atmospheric pressure. Such sources interact strongly with living cells, but experimental studies on bacterial samples show that this interaction has a surprising pattern resulting in circular or annular killing structures. This paper presents numerical simulations showing that this pattern occurs because biologically active reactive oxygen and nitrogen species are produced dominantly where effluent from the plasma needle interacts with ambient air. A novel solution strategy is utilised coupling plasma produced neutral (uncharged) reactive species to the gas dynamics solving for steady state profiles at the treated biological surface. Numerical results are compared with experimental reports corroborating evidence for atomic oxygen as a key bactericidal species. Surface losses are considered for interaction of plasma produced reactants with reactive solid and liquid interfaces. Atomic oxygen surface reactions on a reactive solid surface with adsorption probabilities above 0.1 are shown to be limited by the flux of atomic oxygen from the plasma. Interaction of the source with an aqueous surface showed hydrogen peroxide as the dominant species at this interface.

  1. Characterization of water quality and simulation of temperature, nutrients, biochemical oxygen demand, and dissolved oxygen in the Wateree River, South Carolina, 1996-98

    USGS Publications Warehouse

    Feaster, Toby D.; Conrads, Paul A.

    2000-01-01

    In May 1996, the U.S. Geological Survey entered into a cooperative agreement with the Kershaw County Water and Sewer Authority to characterize and simulate the water quality in the Wateree River, South Carolina. Longitudinal profiling of dissolved-oxygen concentrations during the spring and summer of 1996 revealed dissolved-oxygen minimums occurring upstream from the point-source discharges. The mean dissolved-oxygen decrease upstream from the effluent discharges was 2.0 milligrams per liter, and the decrease downstream from the effluent discharges was 0.2 milligram per liter. Several theories were investigated to obtain an improved understanding of the dissolved-oxygen dynamics in the upper Wateree River. Data suggest that the dissolved-oxygen concentration decrease is associated with elevated levels of oxygen-consuming nutrients and metals that are flowing into the Wateree River from Lake Wateree. Analysis of long-term streamflow and water-quality data collected at two U.S. Geological Survey gaging stations suggests that no strong correlation exists between streamflow and dissolved-oxygen concentrations in the Wateree River. However, a strong negative correlation does exist between dissolved-oxygen concentrations and water temperature. Analysis of data from six South Carolina Department of Health and Environmental Control monitoring stations for 1980.95 revealed decreasing trends in ammonia nitrogen at all stations where data were available and decreasing trends in 5-day biochemical oxygen demand at three river stations. The influence of various hydrologic and point-source loading conditions on dissolved-oxygen concentrations in the Wateree River were determined by using results from water-quality simulations by the Branched Lagrangian Transport Model. The effects of five tributaries and four point-source discharges were included in the model. Data collected during two synoptic water-quality samplings on June 23.25 and August 11.13, 1997, were used to calibrate

  2. Method and apparatus for the gas phase decontamination of chemical and biological agents

    DOEpatents

    O'Neill, Hugh J.; Brubaker, Kenneth L.

    2003-10-07

    An apparatus and method for decontaminating chemical and biological agents using the reactive properties of both the single atomic oxygen and the hydroxyl radical for the decontamination of chemical and biological agents. The apparatus is self contained and portable and allows for the application of gas reactants directly at the required decontamination point. The system provides for the use of ultraviolet light of a specific spectral range to photolytically break down ozone into molecular oxygen and hydroxyl radicals where some of the molecular oxygen is in the first excited state. The excited molecular oxygen will combine with water vapor to produce two hydroxyl radicals.

  3. Biological warfare agents.

    PubMed

    Pohanka, Miroslav; Kuca, Kamil

    2010-01-01

    Biological warfare agents are a group of pathogens and toxins of biological origin that can be potentially misused for military or criminal purposes. The present review attempts to summarize necessary knowledge about biological warfare agents. The historical aspects, examples of applications of these agents such as anthrax letters, biological weapons impact, a summary of biological warfare agents and epidemiology of infections are described. The last section tries to estimate future trends in research on biological warfare agents.

  4. Ordinary Chondrite Chondrules: Oxygen Isotope Variations

    NASA Astrophysics Data System (ADS)

    Metzler, K.; Pack, A.; Hezel, D. C.

    2017-02-01

    Chondrules in some H and LL chondrites show positive/negative correlations between size and oxygen isotopic composition. This indicates that they exchanged oxygen with different oxygen reservoirs and cannot stem from a common chondrule population.

  5. Biological patterns: Novel indicators for pharmacological assays

    NASA Technical Reports Server (NTRS)

    Johnson, Jacqueline U.

    1991-01-01

    Variable gravity testing using the KC-135 demonstrated clearly that biological pattern formation was definitely shown to result from gravity alone, and not from oxygen gradients in solution. Motile pattern formation of spermatozoa are driven by alternate mechanisms, and apparently not affected by short-term changes in gravity. The chemical effects found appear to be secondary to the primary effect of gravity. Cryopreservation may be the remedy to the problem of 'spare' or 'standing order' biological samples for testing of space lab investigations, but further studies are necessary.

  6. [Biology and mechanobiology of the intervertebral disc].

    PubMed

    González Martínez, Emilio; García-Cosamalón, José; Cosamalón-Gan, Iván; Esteban Blanco, Marta; García-Suarez, Olivia; Vega, José A

    2017-01-24

    The intervertebral disc (IVD) is noted for its low cell content, and being the largest avascular structure of human body. The low amount of cells in the disc have to adapt to an anaerobic metabolism with low oxygen pressure and acidic pH. Apart from surviving in an adverse microenvironment, they are exposed to a high level of mechanical stress. The biological adaptation of cells to acidosis and hyperosmolarity conditions are regulated by mechanoproteins, which are responsible for converting a mechanical signal into a cellular response, thus modifying its gene expression. Mechanobiology helps us to better understand the pathophysiology of IVD and its potential biological repair.

  7. The Measurement of Dissolved Oxygen

    ERIC Educational Resources Information Center

    Thistlethwayte, D.; And Others

    1974-01-01

    Describes an experiment in environmental chemistry which serves to determine the dissolved oxygen concentration in both fresh and saline water. Applications of the method at the undergraduate and secondary school levels are recommended. (CC)

  8. Solid State oxygen Sensor Development

    NASA Technical Reports Server (NTRS)

    Cheung, Jeffery T.; Johnson, Scott R.

    1994-01-01

    To anticipate future long-duration mission needs for life support sensors, we explored the feasibility of using thin-film metal-oxide semiconductors. The objective of this task was to develop gas sensors for life support applications which would be suitable for long-duration missions. Metal oxides, such as ZnO, SnO2, and TiO2 have been shown to react with oxygen molecules. Oxygen lowers the metal oxide's electrical resistance. Critical to the performance is the application of the oxide in a thin film on an inert substrate: the thinner the film, the more readily the oxygen penetration and hence the more rapid and sensitive the sensor. Metal oxides are not limited to oxygen detection, rather, oxides offer detection and quantification applications to the complete range of gases of interest, not only for life support systems, but for propellants as well.

  9. Oxygen sensitive, refractory oxide composition

    DOEpatents

    Holcombe, Jr., Cressie E.; Smith, Douglas D.

    1976-01-01

    Oxide compositions containing niobium pentoxide and an oxide selected from the group consisting of hafnia, titania, and zirconia have electrical conductivity characteristics which vary greatly depending on the oxygen content.

  10. A new oxygen transport agent.

    PubMed

    Standl, Thomas

    2005-04-01

    Modern highly purified and chemically modified hemoglobin-based oxygen carriers (HBOC) are free of significant side effects on kidneys and coagulation, and they do not possess ABO antigens, allowing transfusion without knowledge of the respective blood group. Even at room air oxygen concentrations HBOC can compensate for intravascular volume deficits in hemorrhagic shock, including restoration of colloid osmotic pressure and organ perfusion, and deliver oxygen to organs and tissues during nearly complete blood exchange. In animal experiments and clinical trials all HBOC showed a vasoconstrictive side-effect which is mainly caused by nitric oxide scavenging, and to a lesser extent by reactive vasoconstriction because of precapillary oxygen off-loading. The study by Bjorkholm in this issue of the journal (see page 505) investigates the application of a moderate dose of the newly designed HBOC, MP4, in volunteers. MP4 has a high molecular size and a very low p50 resulting in a high oxygen affinity thus avoiding significant (pre)capillary oxygen off-loading. No significant rises in blood pressure or major laboratory abnormalities were seen after MP4 infusion. This new HBOC may be applicable in patients as a red blood substitute where vasoconstriction must be avoided. In addition, poststenotic tissue oxygenation might be a further indication. However, the number of treated volunteers and the infused dose of MP4 were both are very small. Therefore, one cannot draw conclusions on the safety, tolerability and efficacy of MP4 in terms of red cell replacement when large amounts of oxygen carriers are needed.

  11. Oxygen chemisorption on copper (110)

    NASA Astrophysics Data System (ADS)

    Mundenar, J. M.; Baddorf, A. P.; Plummer, E. W.; Sneddon, L. G.; Didio, R. A.; Zehner, D. M.

    1987-09-01

    High resolution electron energy loss spectroscopy (EELS) and angle-resolved ultra-violet photoelectron spectroscopy (UPS) have been used: (1) to study a surface phonon of Cu(110) as a function of oxygen coverage, (2) to identify oxygen adsorption site(s) in the p(2×1)O, c(6×2)O, and disordered oxygen overlayer (formed by O 2 exposure at 100 K), and (3) to determine whether molecular adsorption or dissociation of O 2 followed by atomic adsorption occurs after oxygen exposure at 100 K. With EELS, a continuous shift in energy of the surface phonon as a function of oxygen exposure at 300 K is observed. Our EELS data for the p(2×1)O overlayer support previous reports of a single long-bridge adsorption site, while indicating two sites are populated in the c(6×2)O overlayer: a long-bridge site and a four-coordinated site. The long-bridge site is populated at all coverages while the four-coordinated sites is occupied only after high exposures (≥2×10 4 L) at room temperature, or after exposures >2 L at low temperature (100 K). For both conditions the oxygen coverages are greater than 0.5 monolayer. Also, EELS and complementary UPS data clearly show that oxygen adsorbs dissociatively on Cu(110) after O 2 exposure at 100 K. At this temperature, LEED results indicate that the oxygen atoms are adsorbed without long-range order; however, local adsorption sites, which are similar to those in the c(6×2)O surface, are observed.

  12. Rapid field estimation of biochemical oxygen demand in a subtropical eutrophic urban lake with chlorophyll a fluorescence.

    PubMed

    Xu, Zhen; Xu, Y Jun

    2015-01-01

    Development of a technique for rapid field estimation of biochemical oxygen demand (BOD) is necessary for cost-effective monitoring and management of urban lakes. While several studies reported the usefulness of laboratory tryptophan-like fluorescence technique in predicting 5-day BOD (BOD₅) of wastewater and leachates, little is known about the predictability of field chlorophyll fluorescence measurements for BOD of urban lake waters that are constantly exposed to the mixture of chemical compounds. This study was conducted to develop a numeric relationship between chlorophyll a fluorescence and BOD for a eutrophic urban lake that is widely representative of lake water conditions in the subtropical southern USA. From October 2012 to September 2013, in situ measurements at the studied lake were made every 2 weeks on chlorophyll a fluorescence and other water quality parameters including water temperature, pH, dissolved oxygen, and specific conductivity. Water samples were taken for 5-day BOD and 10-day BOD (BOD₁₀) analysis with and without incubation. The results showed a clear seasonal trend of both BOD measurements being high during the summer and low during the winter. There was a linear, positive relationship between chlorophyll a fluorescence and BOD, and the relationship appeared to be stronger with the 10-day BOD (r(2) = 0.83) than with the 5-day BOD (r(2) = 0.76). BOD dropped each day with declining chlorophyll a fluorescence, suggesting that die-off of phytoplankton has been the main consumption of oxygen in the studied lake. Ambient conditions such as rainfall and water temperature may have partially affected BOD variation.

  13. Oxygen and Early Animal Evolution

    NASA Astrophysics Data System (ADS)

    Xiao, S.

    2012-12-01

    It is often hypothesized that the rise of animals was triggered by an increase in O2 levels in the atmosphere and oceans. However, this hypothesis is remarkably difficult to test, because the timing of animal divergences is poorly resolved, the physiology of early animals is often unknown, estimates of past pO2 levels come with large error bars, and causal relationships between oxygenation and animal evolution are difficult to establish. Nonetheless, existing phylogenetic, paleontological, and geochemical data indicate that the evolution of macroscopic animals and motile macrometazoans with energetically expensive lifestyles may be temporally coupled with ocean oxygenation events in the Ediacaran Period. Thus, it is plausible that ocean oxygenation may have been a limiting factor in the early evolution of macroscopic, complex, and metabolically aggressive animals (particularly bilaterian animals). However, ocean oxygenation and animal evolution were likely engaged in two-way interactions: Ediacaran oxygenation may have initially lifted a physiological barrier for the evolution of animal size, motility, and active lifestyles, but subsequent animal diversification in the Paleozoic may have also changed oceanic redox structures. Viewed in a broader context, the early evolutionary history of animals was contingent upon a series of events, including genetic preparation (developmental genetics), environmental facilitation (oceanic oxygenation), and ecological escalation (Cambrian explosion), but the rise of animals to ecological importance also had important geobiological impacts on oceanic redox structures, sedimentary fabrics, and global geochemical cycles.

  14. Efficacy and safety of pharmacokinetically enhanced amoxicillin-clavulanate at 2,000/125 milligrams twice daily for 5 days versus amoxicillin-clavulanate at 875/125 milligrams twice daily for 7 days in the treatment of acute exacerbations of chronic bronchitis.

    PubMed

    Sethi, Sanjay; Breton, John; Wynne, Brian

    2005-01-01

    This randomized, controlled trial was designed to show that a short, 5-day course of pharmacokinetically enhanced amoxicillin-clavulanate at 2,000/125 mg (Augmentin XR) is as effective clinically as a longer, 7-day course of conventional amoxicillin-clavulanate at 875/125 mg (both given twice daily) in the treatment of acute exacerbations of chronic bronchitis (AECB). Amoxicillin-clavulanate at 2,000/125 mg was designed to extend the therapeutic levels of amoxicillin in serum over the 12-h dosing interval, compared with conventional formulations, to eradicate bacterial strains for which amoxicillin MICs were < or =4 microg/ml while retaining efficacy against beta-lactamase-producing pathogens. A total of 893 patients were randomized and received study medication (amoxicillin-clavulanate at 2,000/125 mg for 443 patients and 875/125 mg for 450 patients). Overall, 141 patients receiving amoxicillin-clavulanate at 2,000/125 mg and 135 receiving the comparator formulation had at least one pathogen identified at screening. Amoxicillin-clavulanate at 2,000/125 mg was as effective clinically in the per-protocol (PP) population at the test of cure (days 14 to 21, primary efficacy endpoint) as amoxicillin-clavulanate at 875/125 mg (clinical success rates of 93.0 and 91.2%, respectively; treatment difference, 1.8; 95% confidence interval [CI], -2.2, 5.7). Bacteriological success in the bacteriology PP population was high for both formulations (amoxicillin-clavulanate at 2,000/125 mg, 76.7%; amoxicillin-clavulanate at 875/125 mg, 73.0%; treatment difference, 3.8; 95% CI, -7.5, 15.0). Both therapies were well tolerated, with a similar incidence of adverse events. Fewer than 5% of patients in each group withdrew from the study due to adverse events. The shorter, 5-day course of amoxicillin-clavulanate at 2,000/125 mg was shown to be as effective clinically as a longer, 7-day course of amoxicillin-clavulanate at 875/125 mg, with high bacteriological efficacy and no difference in

  15. Oxygen Transport Ceramic Membranes

    SciTech Connect

    S. Bandopadhyay; N. Nagabhushana; X.-D Zhou; Q. Cai; J. Yang; W.B. Yelon; W.J. James; H.U. Anderson; Alan Jacobson; C.A. Mims

    2004-05-01

    the LSCrF-2828 membrane to produce the gradients which exist under syngas generation conditions. The CO-CO{sub 2} mixtures have normal isotopic {sup 18}O abundances. The evolution of {sup 18}O on the delivery side in these experiments after an {sup 18}O pulse on the air side reveals a wealth of information about the oxygen transport processes.

  16. Biological waste air treatment in biofilters.

    PubMed

    Deshusses, M A

    1997-06-01

    Recent studies in the area of biological waste air treatment in biofilters have addressed fundamental key issues such as microbial dynamics, microscopical characterization of the process culture and oxygen and nutrient limitations. The results from these studies have provided a deeper insight into the overall biofiltration process. In the coming years, such advances should allow for the design of better reactor controls and the improvement of pollutant removal in gas-phase bioreactors.

  17. OXYGEN PRESSURES IN THE INTERSTITIAL SPACE OF SKELETAL MUSCLE AND TUMORS IN VIVO

    PubMed Central

    Wilson, David F.; Lee, William M.F.; Makonnen, Sosina; Apreleva, Sophia; Vinogradov, Sergei A.

    2008-01-01

    A new Oxyphor (Oxyphor G3) has been used to selectively determine the oxygen pressure in interstitial (pericellular) spaces. Oxyphor G3 is a Pd-tetrabenzoporphyrin, encapsulated inside generation 2 poly-arylglycine (AG) dendrimer, and therefore is a true near infrared oxygen sensor, having a strong absorption band at 636nm and emission near 800nm. The periphery of the dendrimer is modified with oligoethylene glycol residues (Av. MW 350) to make the probe water soluble and biologically inert. Oxyphor G3 was injected along “tracks” in the tissue using a small needle (30gage or less) and remained in the pericellular space, allowing oxygen measurements for several hours with a single injection. The oxygen pressure distributions (histograms) were compared with those for Oxyphor G2 in the intravascular (blood plasma) space. In normal muscle, in the lower oxygen pressure region of the histograms (capillary bed) the oxygen pressure difference was small. At higher oxygen pressures in the histograms there were differences consistent with the presence of high flow vessels with oxygen pressures substantially above those of the surrounding interstitial space. In tumors, the oxygen pressures in the two spaces were similar but with large differences among tumors. In mice, anesthesia with ketamine plus xylazine markedly decreased oxygen pressures in the interstitial and intravascular spaces compared to awake or isoflurane anesthetized mice. PMID:18290314

  18. Decavanadate effects in biological systems.

    PubMed

    Aureliano, Manuel; Gândara, Ricardo M C

    2005-05-01

    Vanadium biological studies often disregarded the formation of decameric vanadate species known to interact, in vitro, with high-affinity with many proteins such as myosin and sarcoplasmic reticulum calcium pump and also to inhibit these biochemical systems involved in energy transduction. Moreover, very few in vivo animal studies involving vanadium consider the contribution of decavanadate to vanadium biological effects. Recently, it has been shown that an acute exposure to decavanadate but not to other vanadate oligomers induced oxidative stress and a different fate in vanadium intracellular accumulation. Several markers of oxidative stress analyzed on hepatic and cardiac tissue were monitored after in vivo effect of an acute exposure (12, 24 h and 7 days), to a sub-lethal concentration (5 mM; 1 mg/kg) of two vanadium solutions ("metavanadate" and "decavanadate"). It was observed that "decavanadate" promote different effects than other vanadate oligomers in catalase activity, glutathione content, lipid peroxidation, mitochondrial superoxide anion production and vanadium accumulation, whereas both solutions seem to equally depress reactive oxygen species (ROS) production as well as total intracellular reducing power. Vanadium is accumulated in mitochondria in particular when "decavanadate" is administered. These recent findings, that are now summarized, point out the decameric vanadate species contributions to in vivo and in vitro effects induced by vanadium in biological systems.

  19. High-Oxygen Planetary Atmospheres and the Existence of Intelligent Life in the Universe

    NASA Astrophysics Data System (ADS)

    Catling, D. C.; McKay, C. P.

    1999-09-01

    The existence of a high partial pressure of oxygen in planetary atmospheres elsewhere in the universe is a likely prerequisite for the existence of animal-like life and hence the existence of intelligent life. Whether a planet develops such an atmosphere is influenced by planetary parameters including the composition and size of the planet. The transition to a high oxygen atmosphere would depend on the ability of plate tectonics to provide for organic carbon burial that prohibits back-reaction with photosynthesized atmospheric oxygen. On Earth, plate tectonics accompanied by the oxygen production of photosynthetic bacteria in the Precambrian oceans led to the growth in the level of atmospheric oxygen detectable around 2.0 Gyr ago. Thus, there is a minimum size for an extrasolar planet that develops a high oxygen atmosphere based on the requirement to sustain plate tectonics. On the other hand, if the planet were too big, the loss of early hydrogen may be too slow on the timescale of solar evolution. The timing of the accumulation of atmospheric oxygen, which on Earth resulted in the biological evolution of eukaryotes (eventually including oxygen-utilizing metazoans such as ourselves), would thus appear to depend on geophysics. This may imply a relationship between planetary size and possible degree of biological complexity through time on terrestrial-type planets elsewhere in the Universe.

  20. Noninvasive approaches to measuring respiratory patterns using a PtTFPP based phase-lifetime self-referencing oxygen optrode

    NASA Astrophysics Data System (ADS)

    Porterfield, D. Marshall; Rickus, Jenna L.; Kopelman, Raoul

    2006-10-01

    Optically transduced sensors (optrodes, or optodes) offer significant advantages over polarographic techniques for measuring oxygen. In biology and medicine, how we make measurements is very important, and this is especially true in terms of physiological exchange. Cellular and tissue oxygenation is a function of background concentration and respiratory demand, and in pure physical terms this is best expressed in terms of molecular flux based on Fick's law. Measuring dynamic flux from biological systems requires sensing technology that can measure activity in multiple dimensions. Here we report the development of a self-referencing oxygen optrode (SRO) for reliably making noninvasive measurements of oxygen flux from a variety of biological systems. The self-referencing microsensor technique was adapted to operate optrodic oxygen sensors through the integration of optical sensing instrumentation with software-controlled data acquisition and micro-stepping motion control. This allows the sensor to scan biologically active gradients of oxygen flux directly, as it relates to cellular and tissue respiratory activity. The technique was validated first using artificially generated oxygen gradients, which are theoretically modelled and compare with measured signals. Subsequently, the SRO was applied in basic research applications to non-invasively measure molecular oxygen flux from a variety of animal and plant systems.

  1. Effects of hyperbaric oxygen at 1.25 atmospheres absolute with normal air on macrophage number and infiltration during rat skeletal muscle regeneration.

    PubMed

    Fujita, Naoto; Ono, Miharu; Tomioka, Tomoka; Deie, Masataka

    2014-01-01

    Use of mild hyperbaric oxygen less than 2 atmospheres absolute (2026.54 hPa) with normal air is emerging as a common complementary treatment for severe muscle injury. Although hyperbaric oxygen at over 2 atmospheres absolute with 100% O2 promotes healing of skeletal muscle injury, it is not clear whether mild hyperbaric oxygen is equally effective. The purpose of the present study was to investigate the impact of hyperbaric oxygen at 1.25 atmospheres absolute (1266.59 hPa) with normal air on muscle regeneration. The tibialis anterior muscle of male Wistar rats was injured by injection of bupivacaine hydrochloride, and rats were randomly assigned to a hyperbaric oxygen experimental group or to a non-hyperbaric oxygen control group. Immediately after the injection, rats were exposed to hyperbaric oxygen, and the treatment was continued for 28 days. The cross-sectional area of centrally nucleated muscle fibers was significantly larger in rats exposed to hyperbaric oxygen than in controls 5 and 7 days after injury. The number of CD68- or CD68- and CD206-positive cells was significantly higher in rats exposed to hyperbaric oxygen than in controls 24 h after injury. Additionally, tumor necrosis factor-α and interleukin-10 mRNA expression levels were significantly higher in rats exposed to hyperbaric oxygen than in controls 24 h after injury. The number of Pax7- and MyoD- or MyoD- and myogenin-positive nuclei per mm2 and the expression levels of these proteins were significantly higher in rats exposed to hyperbaric oxygen than in controls 5 days after injury. These results suggest that mild hyperbaric oxygen promotes skeletal muscle regeneration in the early phase after injury, possibly due to reduced hypoxic conditions leading to accelerated macrophage infiltration and phenotype transition. In conclusion, mild hyperbaric oxygen less than 2 atmospheres absolute with normal air is an appropriate support therapy for severe muscle injuries.

  2. Hyperbaric oxygenation alters carotid body ultrastructure and function.

    PubMed

    Torbati, D; Sherpa, A K; Lahiri, S; Mokashi, A; Albertine, K H; DiGiulio, C

    1993-05-01

    We previously demonstrated that chronic normobaric hyperoxia (NH) for 60-67 h attenuated the carotid chemosensory response to hypoxia, probably initiated by the generation of reactive oxygen species (ROS). Since biological systems are affected by oxygen in a dose-dependent manner, we hypothesized that hyperbaric oxygenation (HBO) would affect the cellular mechanisms of oxygen chemoreception in a shorter time. To test the hypothesis, we studied the effects of oxygen at 5 atmospheres absolute (ATA) on cats (n = 7) carotid body ultrastructure and chemosensory responses to hypoxia, hypercapnia, and to bolus injections of cyanide, nicotine and dopamine. Four control cats breathed room air at 1 ATA. At the termination of the experiments, carotid bodies from 4 cats in each group were fixed and prepared for electron microscopy and morphometry. On the average, HBO diminished the chemosensory responsiveness to hypoxia (P < 0.01, unpaired t-test) within about 2 h, supporting the hypothesis. The responses to hypercapnia or bolus injections of cyanide, nicotine and dopamine were normal. HBO did not diminish the distribution of the dense-cored vesicles but significantly increased the mean volume-density of mitochondria and decreased the cristated area per mitochondrion in the glomus cells. The latter suggests a link between oxidative metabolism and chemosensing, and the former excludes availability of neurotransmitters being the cause of the blunted chemosensory response to hypoxia.

  3. Image-based modelling of skeletal muscle oxygenation.

    PubMed

    Zeller-Plumhoff, B; Roose, T; Clough, G F; Schneider, P

    2017-02-01

    The supply of oxygen in sufficient quantity is vital for the correct functioning of all organs in the human body, in particular for skeletal muscle during exercise. Disease is often associated with both an inhibition of the microvascular supply capability and is thought to relate to changes in the structure of blood vessel networks. Different methods exist to investigate the influence of the microvascular structure on tissue oxygenation, varying over a range of application areas, i.e. biological in vivo and in vitro experiments, imaging and mathematical modelling. Ideally, all of these methods should be combined within the same framework in order to fully understand the processes involved. This review discusses the mathematical models of skeletal muscle oxygenation currently available that are based upon images taken of the muscle microvasculature in vivo and ex vivo Imaging systems suitable for capturing the blood vessel networks are discussed and respective contrasting methods presented. The review further informs the association between anatomical characteristics in health and disease. With this review we give the reader a tool to understand and establish the workflow of developing an image-based model of skeletal muscle oxygenation. Finally, we give an outlook for improvements needed for measurements and imaging techniques to adequately investigate the microvascular capability for oxygen exchange.

  4. Image-based modelling of skeletal muscle oxygenation

    PubMed Central

    Clough, G. F.

    2017-01-01

    The supply of oxygen in sufficient quantity is vital for the correct functioning of all organs in the human body, in particular for skeletal muscle during exercise. Disease is often associated with both an inhibition of the microvascular supply capability and is thought to relate to changes in the structure of blood vessel networks. Different methods exist to investigate the influence of the microvascular structure on tissue oxygenation, varying over a range of application areas, i.e. biological in vivo and in vitro experiments, imaging and mathematical modelling. Ideally, all of these methods should be combined within the same framework in order to fully understand the processes involved. This review discusses the mathematical models of skeletal muscle oxygenation currently available that are based upon images taken of the muscle microvasculature in vivo and ex vivo. Imaging systems suitable for capturing the blood vessel networks are discussed and respective contrasting methods presented. The review further informs the association between anatomical characteristics in health and disease. With this review we give the reader a tool to understand and establish the workflow of developing an image-based model of skeletal muscle oxygenation. Finally, we give an outlook for improvements needed for measurements and imaging techniques to adequately investigate the microvascular capability for oxygen exchange. PMID:28202595

  5. Herschel Oxygen Project Observations of Molecular Oxygen in Orion

    NASA Astrophysics Data System (ADS)

    Goldsmith, P. F.; Liseau, R.; Bell, T. A.; Lis, D. C.; Chen, J. H.; Snell, R.; Li, D.; Kaufman, M.; Bergin, E. A.; Melnick, G.; HOP Team

    2011-05-01

    Oxygen is the third most abundant element in the cosmos. In the gas phase, oxygen can be ionized, atomic, or in molecular, and it is also incorporated into interstellar grains. Models of the gas-phase chemistry in dense clouds predict molecular oxygen (O2) to be almost as abundant as carbon monoxide (CO). A number of searches for molecular oxygen have been carried out, including ground-based searches for the isotopologue 16O18O and searches for O2 in redshifted galaxies. Searches for Galactic O2 carried out with the SWAS and Odin spacecraft have yielded upper limits on the abundance of molecular oxygen typically 1 to 2 orders of magnitude below those predicted by gas-phase models. There has been a detection of a single transition of O2 in one source, again indicating a low abundance. A variety of explanations have been proposed to explain this low abundance. Some of these are based on depletion of atomic oxygen onto dust grains, resulting in incorporation of this species into water that remains on the grain surface. Available gas-phase oxygen is largely incorporated into CO, leaving little for gas-phase O2. Other models involve circulation of material between UV-irradiated and well-shielded regions, and highly clumpy cloud structure. The Herschel Open Time Key Project HOP (Herschel Oxygen Project) addresses this important problem in astrochemistry, exploiting the high angular resolution and sensitivity of the Herschel HIFI instrument to observe 3 rotational transitions of O2 in a broad sample of molecular clouds. The sensitivity and angular resolution of HIFI are dramatically better than what has previously been available at these frequencies. We will discuss the HOP observations to date, focusing on the detection of O2 towards the H2 Peak 1 position near KL in Orion. This region is heavily impacted by the molecular outflow and resulting shocks which are manifest in the highly-structured emission from pure rotational and rotation-vibration transitions of molecular

  6. Effects of hyperbaric oxygenation on survival time of aluminum phosphide intoxicated rats

    PubMed Central

    Saidi, Hossein; Shokraneh, Farhad; Ghafouri, Hamed-Basir; Shojaie, Shayan

    2011-01-01

    BACKGROUND: Aluminium phosphide (AlP) is used as a fumigant. It produces phosphine gas which is a mitochondrial poison. Although this poisoning has been repeatedly reported in literature with a high mortality rate, there is no known antidote for AlP intoxication. In the present study, we studied the effects of hyperbaric oxygenation (HBO) on the survival time of AlP intoxicated rats. METHODS: Intoxicated rats with AlP (11.5 mg/kg, oral gavage) were placed in hyperbaric oxygenation with different concentrations of compressed air and oxygen. RESULTS: All the animals exposed to AlP died within 5 days. The mean survival times of rats exposed to AlP without any intervention, treated with hyperbaric condition by compressed air, and treated with hyperbaric condition by pure O2 were 91 ± 1, 262 ± 8, and 276 ± 6 minutes, respectively. In analysis of survival times, there was a significant difference between Group 2 which received AlP and the groups which underwent intervention (Groups 2 and 3, p < 0.001; Groups 2 and 4, p < 0.001). CONCLUSIONS: Hyperbaric oxygenation may probably improve the survival time of the intoxicated rats with aluminium phosphide, but it may not decrease the mortality rate. PMID:22973324

  7. Ischemic preconditioning improves oxygen saturation and attenuates hypoxic pulmonary vasoconstriction at high altitude.

    PubMed

    Foster, Gary P; Giri, Paresh C; Rogers, Douglas M; Larson, Sophia R; Anholm, James D

    2014-06-01

    Exposure to hypoxic environments is associated with decreased arterial oxygen saturation and increased pulmonary artery pressures. Ischemic preconditioning of an extremity (IPC) is a procedure that stimulates vasoactive and inflammatory pathways that protect remote organ systems from ongoing or future ischemic injury. To test the effects of IPC on oxygen saturation and pulmonary artery pressures at high altitude, 12 healthy adult volunteers were evaluated in a randomized cross-over trial. IPC was administered utilizing a standardized protocol. IPC or placebo was administered daily for 5 days prior to ascent to altitude. All participants were evaluated twice at 4342 m altitude (placebo and IPC conditions separated by 4 weeks, randomized). The pulmonary artery systolic pressure (PASP) at 4342 m was significantly lower in the IPC condition than the placebo condition (36 ± 6.0 mmHg vs. 38.1 ± 7.6 mmHg, respectively, p = 0.035). Oxygen saturation at 4342 m was significantly higher with IPC compared to placebo (80.3 ± 8.7% vs. 75.3 ± 9.6%, respectively, p = 0.003). Prophylactic IPC treatment is associated with improved oxygen saturation and attenuation of the normal hypoxic increase in pulmonary artery pressures following ascent to high altitude.

  8. Electrons, life and the evolution of Earth's oxygen cycle.

    PubMed

    Falkowski, Paul G; Godfrey, Linda V

    2008-08-27

    The biogeochemical cycles of H, C, N, O and S are coupled via biologically catalysed electron transfer (redox) reactions. The metabolic processes responsible for maintaining these cycles evolved over the first ca 2.3 Ga of Earth's history in prokaryotes and, through a sequence of events, led to the production of oxygen via the photobiologically catalysed oxidation of water. However, geochemical evidence suggests that there was a delay of several hundred million years before oxygen accumulated in Earth's atmosphere related to changes in the burial efficiency of organic matter and fundamental alterations in the nitrogen cycle. In the latter case, the presence of free molecular oxygen allowed ammonium to be oxidized to nitrate and subsequently denitrified. The interaction between the oxygen and nitrogen cycles in particular led to a negative feedback, in which increased production of oxygen led to decreased fixed inorganic nitrogen in the oceans. This feedback, which is supported by isotopic analyses of fixed nitrogen in sedimentary rocks from the Late Archaean, continues to the present. However, once sufficient oxygen accumulated in Earth's atmosphere to allow nitrification to out-compete denitrification, a new stable electron 'market' emerged in which oxygenic photosynthesis and aerobic respiration ultimately spread via endosymbiotic events and massive lateral gene transfer to eukaryotic host cells, allowing the evolution of complex (i.e. animal) life forms. The resulting network of electron transfers led a gas composition of Earth's atmosphere that is far from thermodynamic equilibrium (i.e. it is an emergent property), yet is relatively stable on geological time scales. The early coevolution of the C, N and O cycles, and the resulting non-equilibrium gaseous by-products can be used as a guide to search for the presence of life on terrestrial planets outside of our Solar System.

  9. Oxygen-dependent hyperpolarized (129) Xe brain MR.

    PubMed

    Li, Haidong; Zhang, Zhiying; Zhong, Jianping; Ruan, Weiwei; Han, Yeqing; Sun, Xianping; Ye, Chaohui; Zhou, Xin

    2016-03-01

    Hyperpolarized (HP) (129) Xe MR offers unique advantages for brain functional imaging (fMRI) because of its extremely high sensitivity to different chemical environments and the total absence of background noise in biological tissues. However, its advancement and applications are currently plagued by issues of signal strength. Generally, xenon atoms found in the brain after inhalation are transferred from the lung via the bloodstream. The longitudinal relaxation time (T1 ) of HP (129) Xe is inversely proportional to the pulmonary oxygen concentration in the lung because oxygen molecules are paramagnetic. However, the T1 of (129) Xe is proportional to the pulmonary oxygen concentration in the blood, because the higher pulmonary oxygen concentration will result in a higher concentration of diamagnetic oxyhemoglobin. Accordingly, there should be an optimal pulmonary oxygen concentration for a given quantity of HP (129) Xe in the brain. In this study, the relationship between pulmonary oxygen concentration and HP (129) Xe signal in the brain was analyzed using a theoretical model and measured through in vivo experiments. The results from the theoretical model and experiments in rats are found to be in good agreement with each other. The optimal pulmonary oxygen concentration predicted by the theoretical model was 21%, and the in vivo experiments confirmed the presence of such an optimal ratio by reporting measurements between 25% and 35%. These findings are helpful for improving the (129) Xe signal in the brain and make the most of the limited spin polarization available for brain experiments. Copyright © 2016 John Wiley & Sons, Ltd.

  10. Simultaneous Monitoring of Vascular Oxygenation and Tissue Oxygen Tension of Breast Tumors Under Hyperbaric Oxygen Exposure

    DTIC Science & Technology

    2005-04-01

    Following the same strategy, here, oxygen/carbogen induced tumor blood flow changes were estimated by fitting the Windkessel model ( Mandeville et al 1999...determined by the vasomotor control of arterioles, and that the capillaries and veins passively respond to arterial pressure changes ( Mandeville et al 1999...than normobaric oxygen. Reference: Boas D, Strangman G, Culver J, Hoge R, Jasdzewski G, Poldrack R, Rosen B and Mandeville J 2003 Can the cerebral

  11. Oxygen Overshoot and Recovery during the Paleoproterozoic

    NASA Astrophysics Data System (ADS)

    Holland, H. D.; Bekker, A.

    2010-12-01

    During the Lomagundi Event, ca. 2.25 - 2.06 Ga, marine carbonates recorded the largest and longest positive carbon isotope excursion, the earliest extensive marine sulfate evaporites were deposited, and the Fe2O3/FeO ratio of shales increased significantly. At the end of the Lomagundi Event the carbon isotope values of marine carbonates returned to ~0‰, marine sulfate evaporites again became scarce, but the Fe2O3/FeO ratio of shales remained essentially unchanged. We propose an explanation for this nonlinear transition of the atmosphere-ocean system from its Archean, mildly reduced state to its Paleoproterozoic, oxygenated state. Before the appearance of significant quantities of atmospheric O2, nearly all of the sulfur in the upper crust was present as a constituent of sulfide minerals. When the O2 content of the atmosphere rose, these sulfides began to be oxidized to sulfate during weathering. Hence, the pH of soil waters decreased, and as a result their phosphate concentration increased. The phosphate flux to the oceans probably also increased, as did the primary productivity and the burial rate of organic matter. The level of atmospheric O2 therefore rose, providing a positive feedback for the intensity of oxidative weathering. The burial of excess organic matter required the biological reduction of bicarbonate carbon, a process that led to highly positive carbon isotope values in marine carbonates. The oxidation of sulfides generated an increase in the seawater sulfate content and the widespread deposition of sulfate evaporites in the Lomagundi-age sedimentary basins. By the end of the Lomagundi Event the sulfide content in the upper crust had been decreased by CaSO4 precipitation in evaporites and in the oceanic crust. As the sulfide content in the upper crust decreased, the pH of groundwaters rebounded to higher values, and the riverine flux of phosphate declined. Primary productivity and oxygen production declined, bringing carbon isotope values of

  12. Oxygen Transport Ceramic Membranes

    SciTech Connect

    S. Bandopadhyay; T. Nithyanantham; X.-D Zhou; Y-W. Sin; H.U. Anderson; Alan Jacobson; C.A. Mims

    2005-05-01

    been admitted to the delivery side of the LSCrF-2828 membrane to produce the gradients which exist under syngas generation conditions. The CO-CO{sub 2} mixtures have normal isotopic {sup 18}O abundances. The evolution of {sup 18}O on the delivery side in these experiments after an {sup 18}O pulse on the air side reveals a wealth of information about the oxygen transport processes.

  13. Learning Biology by Designing

    ERIC Educational Resources Information Center

    Janssen, Fred; Waarlo, Arend Jan

    2010-01-01

    According to a century-old tradition in biological thinking, organisms can be considered as being optimally designed. In modern biology this idea still has great heuristic value. In evolutionary biology a so-called design heuristic has been formulated which provides guidance to researchers in the generation of knowledge about biological systems.…

  14. Biological conversion system

    DOEpatents

    Scott, C.D.

    A system for bioconversion of organic material comprises a primary bioreactor column wherein a biological active agent (zymomonas mobilis) converts the organic material (sugar) to a product (alcohol), a rejuvenator column wherein the biological activity of said biological active agent is enhanced, and means for circulating said biological active agent between said primary bioreactor column and said rejuvenator column.

  15. EVALUATING AN INNOVATIVE OXYGEN SENSOR FOR REMOTE SUBSURFACE OXYGEN MEASUREMENTS

    SciTech Connect

    Millings, M; Brian Riha, B; Warren Hyde, W; Karen Vangelas, K; Brian02 Looney, B

    2006-10-12

    Oxygen is a primary indicator of whether anaerobic reductive dechlorination and similar redox based processes contribute to natural attenuation remedies at chlorinated solvent contaminated sites. Thus, oxygen is a viable indicator parameter for documenting that a system is being sustained in an anaerobic condition. A team of researchers investigated the adaptation of an optical sensor that was developed for oceanographic applications. The optical sensor, because of its design and operating principle, has potential for extended deployment and sensitivity at the low oxygen levels relevant to natural attenuation. The results of the research indicate this tool will be useful for in situ long-term monitoring applications, but that the traditional characterization tools continue to be appropriate for characterization activities.

  16. Synthetic Biology - The Synthesis of Biology.

    PubMed

    Ausländer, Simon; Ausländer, David; Fussenegger, Martin

    2016-12-11

    Synthetic biology envisages the engineering of man-made living biomachines from standardized components that can perform pre-defined functions in a (self-)controlled manner. Different research strategies and interdisciplinary efforts are pursued to implement engineering principles to biology. The "top-down" strategy exploits nature's incredible diversity of existing, natural parts to construct synthetic compositions of genetic, metabolic or signalling networks with predictable and controllable properties. This mainly application-driven approach results in living factories that produce drugs, biofuels, biomaterials and fine chemicals and results in living pills that are based on engineered cells with the capacity to autonomously detect and treat disease states in vivo. In contrast, the "bottom-up" strategy seeks to be independent of existing living systems by designing biological systems from scratch and synthesizing artificial biological entities not found in nature. This more knowledge-driven approach investigates the reconstruction of minimal biological systems that are capable of performing basic biological phenomena, such as self-organization, self-replication and self-sustainability. Moreover, the syntheses of artificial biological units, such as synthetic nucleotides or amino acids, and their implementation into polymers inside living cells currently set the boundaries between natural and artificial biological systems. In particular, the in vitro design, synthesis and transfer of complete genomes into host cells and the application of efficient genome-wide intervention techniques point to the future of synthetic biology: the creation of living designer cells with tailored desirable properties for biomedicine and biotechnology.

  17. Systems interface biology

    PubMed Central

    Doyle, Francis J; Stelling, Jörg

    2006-01-01

    The field of systems biology has attracted the attention of biologists, engineers, mathematicians, physicists, chemists and others in an endeavour to create systems-level understanding of complex biological networks. In particular, systems engineering methods are finding unique opportunities in characterizing the rich behaviour exhibited by biological systems. In the same manner, these new classes of biological problems are motivating novel developments in theoretical systems approaches. Hence, the interface between systems and biology is of mutual benefit to both disciplines. PMID:16971329

  18. Systems interface biology.

    PubMed

    Doyle, Francis J; Stelling, Jörg

    2006-10-22

    The field of systems biology has attracted the attention of biologists, engineers, mathematicians, physicists, chemists and others in an endeavour to create systems-level understanding of complex biological networks. In particular, systems engineering methods are finding unique opportunities in characterizing the rich behaviour exhibited by biological systems. In the same manner, these new classes of biological problems are motivating novel developments in theoretical systems approaches. Hence, the interface between systems and biology is of mutual benefit to both disciplines.

  19. 46 CFR 197.326 - Oxygen safety.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Oxygen safety. 197.326 Section 197.326 Shipping COAST... GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.326 Oxygen safety. (a) Equipment used with oxygen or oxygen mixtures greater than 40 percent by volume must be designed for such use. (b)...

  20. 21 CFR 868.5580 - Oxygen mask.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Oxygen mask. 868.5580 Section 868.5580 Food and... ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5580 Oxygen mask. (a) Identification. An oxygen mask is a device placed over a patient's nose, mouth, or tracheostomy to administer oxygen or aerosols. (b)...