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Sample records for acute oxygen sensing

  1. Reactive Oxygen Species and Cellular Oxygen Sensing

    PubMed Central

    Cash, Timothy P; Pan, Yi; Simon, M. Celeste

    2008-01-01

    Many organisms activate adaptive transcriptional programs to help them cope with decreased oxygen levels, or hypoxia, in their environment. These responses are triggered by various oxygen sensing systems in bacteria, yeast and metazoans. In metazoans, the hypoxia inducible factors (HIFs) mediate the adaptive transcriptional response to hypoxia by upregulating genes involved in maintaining bioenergetic homeostasis. The HIFs in turn are regulated by HIF-specific prolyl hydroxlase activity, which is sensitive to cellular oxygen levels and other factors such as tricarboxylic acid cycle metabolites and reactive oxygen species (ROS). Establishing a role for ROS in cellular oxygen sensing has been challenging since ROS are intrinsically unstable and difficult to measure. However, recent advances in fluorescence energy transfer resonance (FRET)-based methods for measuring ROS are alleviating some of the previous difficulties associated with dyes and luminescent chemicals. In addition, new genetic models have demonstrated that functional mitochondrial electron transport and associated ROS production during hypoxia are required for HIF stabilization in mammalian cells. Current efforts are directed at how ROS mediate prolyl hydroxylase activity and hypoxic HIF stabilization. Progress in understanding this process has been enhanced by the development of the FRET-based ROS probe, an vivo prolyl hydroxylase reporter and various genetic models harboring mutations in components of the mitochondrial electron transport chain. PMID:17893032

  2. Acute use of oxygen therapy

    PubMed Central

    Pilcher, Janine; Beasley, Richard

    2015-01-01

    Summary A major change is needed in the entrenched culture of routinely administering high-concentration oxygen to acutely ill patients regardless of need. Oxygen is a drug that should be prescribed for specific indications. There should be a documented target range for oxygen saturation, and regular monitoring of the patient’s response. There are risks from unrelieved hypoxaemia due to insufficient oxygen therapy, and from provoked hyperoxaemia due to excessive oxygen therapy. Oxygen therapy should therefore be titrated so that the saturation is within a range that avoids these risks. If oxygen requirements are increasing, the clinician should review the patient and consider transfer to a higher level of care. If oxygen requirements are decreasing, consider reducing or discontinuing oxygen therapy. PMID:26648631

  3. Oxygen and carbon dioxide sensing

    NASA Technical Reports Server (NTRS)

    Ren, Fan (Inventor); Pearton, Stephen John (Inventor)

    2012-01-01

    A high electron mobility transistor (HEMT) capable of performing as a CO.sub.2 or O.sub.2 sensor is disclosed, hi one implementation, a polymer solar cell can be connected to the HEMT for use in an infrared detection system. In a second implementation, a selective recognition layer can be provided on a gate region of the HEMT. For carbon dioxide sensing, the selective recognition layer can be, in one example, PEI/starch. For oxygen sensing, the selective recognition layer can be, in one example, indium zinc oxide (IZO). In one application, the HEMTs can be used for the detection of carbon dioxide and oxygen in exhaled breath or blood.

  4. Oxygen Sensing Difluoroboron Dinaphthoylmethane Polylactide

    PubMed Central

    DeRosa, Christopher A.; Samonina-Kosicka, Jelena; Fan, Ziyi; Hendargo, Hansford C.; Weitzel, Douglas H.; Palmer, Gregory M.; Fraser, Cassandra L.

    2015-01-01

    Dual emissive luminescence properties of solid-state difluoroboron β-diketonate-poly(lactic acid) (BF2bdk-PLA) materials have been utilized as biological oxygen sensors. Dyes with red-shifted absorption and emission are important for multiplexing and in vivo imaging, thus hydroxyl-functionalized dinaphthoylmethane initiators and dye-PLA conjugates BF2dnm(X)PLA (X = H, Br, I) with extended conjugation were synthesized. The luminescent materials show red-shifted absorbance (~435 nm) and fluorescence tunability by molecular weight. Fluorescence colors range from yellow (~530 nm) in 10 – 12 kDa polymers to green (~490 nm) in 20 – 30 kDa polymers. Room-temperature phosphorescence (RTP) and thermally activated delayed fluorescence (TADF) are present under a nitrogen atmosphere. For the iodine-substituted derivative, BF2dnm(I)PLA, clearly distinguishable fluorescence (green) and phosphorescence (orange) peaks are present, making it ideal for ratiometric oxygen-sensing and imaging. Bromide and hydrogen analogues with weaker relative phosphorescence intensities and longer phosphorescence lifetimes can be used as highly sensitive, concentration independent, lifetime-based oxygen sensors or for gated emission detection. BF2dnm(I)PLA nanoparticles were taken up by T41 mouse mammary cells and successfully demonstrated differences in vitro ratiometric measurement of oxygen. PMID:26056421

  5. Oxygen sensing strategies in mammals and bacteria.

    PubMed

    Taabazuing, Cornelius Y; Hangasky, John A; Knapp, Michael J

    2014-04-01

    The ability to sense and adapt to changes in pO2 is crucial for basic metabolism in most organisms, leading to elaborate pathways for sensing hypoxia (low pO2). This review focuses on the mechanisms utilized by mammals and bacteria to sense hypoxia. While responses to acute hypoxia in mammalian tissues lead to altered vascular tension, the molecular mechanism of signal transduction is not well understood. In contrast, chronic hypoxia evokes cellular responses that lead to transcriptional changes mediated by the hypoxia inducible factor (HIF), which is directly controlled by post-translational hydroxylation of HIF by the non-heme Fe(II)/αKG-dependent enzymes FIH and PHD2. Research on PHD2 and FIH is focused on developing inhibitors and understanding the links between HIF binding and the O2 reaction in these enzymes. Sulfur speciation is a putative mechanism for acute O2-sensing, with special focus on the role of H2S. This sulfur-centered model is discussed, as are some of the directions for further refinement of this model. In contrast to mammals, bacterial O2-sensing relies on protein cofactors that either bind O2 or oxidatively decompose. The sensing modality for bacterial O2-sensors is either via altered DNA binding affinity of the sensory protein, or else due to the actions of a two-component signaling cascade. Emerging data suggests that proteins containing a hemerythrin-domain, such as FBXL5, may serve to connect iron sensing to O2-sensing in both bacteria and humans. As specific molecular machinery becomes identified, these hypoxia sensing pathways present therapeutic targets for diseases including ischemia, cancer, or bacterial infection. PMID:24468676

  6. Oxygen Sensing Strategies in Mammals and Bacteria

    PubMed Central

    Taabazuing, Cornelius Y.; Hangasky, John A.; Knapp, Michael J.

    2014-01-01

    The ability to sense and adapt to changes in pO2 is crucial for basic metabolism in most organisms, leading to elaborate pathways for sensing hypoxia (low pO2). This review focuses on the mechanisms utilized by mammals and bacteria to sense hypoxia. While responses to acute hypoxia in mammalian tissues lead to altered vascular tension, the molecular mechanism of signal transduction is not well understood. In contrast, chronic hypoxia evokes cellular responses that lead to transcriptional changes mediated by the hypoxia inducible factor (HIF), which is directly controlled by post-translational hydroxylation of HIF by the non-heme Fe(II)/αKG-dependent enzymes FIH and PHD2. Research on PHD2 and FIH is focused on developing inhibitors and understanding the links between HIF binding and the O2 reaction in these enzymes. Sulfur speciation is a putative mechanism for acute O2-sensing, with special focus on the role of H2S. This sulfur-centered model is discussed, as are some of the directions for further refinement of this model. In contrast to mammals, bacterial O2-sensing relies on protein cofactors that either bind O2 or oxidatively decompose. The sensing modality for bacterial O2-sensors is either via altered DNA binding affinity of the sensory protein, or else due to the actions of a two-component signaling cascade. Emerging data suggests that proteins containing a hemerythrin-domain, such as FBXL5, may serve to connect iron sensing to O2-sensing in both bacteria and humans. As specific molecular machinery becomes identified, these hypoxia sensing pathways present therapeutic targets for diseases including ischemia, cancer, or bacterial infection. PMID:24468676

  7. Oxygen derived variables in acute respiratory failure.

    PubMed

    Covelli, H D; Nessan, V J; Tuttle, W K

    1983-08-01

    The clinical course of 33 patients with acute respiratory distress syndrome (ARDS) was monitored by noninvasive oxygen derived variables and compared to data obtained by invasive monitoring. A total of 350 data points were used to compare the physiologic shunt fraction (Qsp/Qt) with the ratio of arterial oxygen to inspired oxygen concentration (PaO2/FIO2), the alveolar-arterial oxygen pressure difference [P(A-a)O2], the respiratory index (RI)-[P(A-a)O2/PaO2], and the ratio of arterial oxygen to alveolar oxygen (a/A). The PaO2/FIO2 ratio, the RI and the aA ratio correlated well with Qsp/Qt (r = 0.87 to 0.94). The P(A-a)O2 correlated less well (r = 0.68). Changes in the cardiac index (CI) and the arteriovenous oxygen content difference C(a-v)O2 had only a minimal effect on the correlation of the oxygen derived variables with Qsp/Qt, although a higher correlation resulted when these extrapulmonary factors were within normal range. We conclude that a number of oxygen derived variables may accurately reflect the degree of Qsp/Qt. The PaO2/FIO2 ratio is the easiest of these variables to calculate, yet accurately predicts the degree of Qsp/Qt throughout a course of acute respiratory failure. PMID:6409506

  8. A miniature inexpensive, oxygen sensing element

    SciTech Connect

    Arenz, R.W.

    1991-10-07

    An exhaustive study was conducted to determine the feasibility of Nernst-type oxygen sensors based on ceramics containing Bi{sub 2}O{sub 3}. The basic sensor design consisted of a ceramic sensing module sealed into a metal tube. The module accommodated an internal heater and thermocouple. Thermal-expansion-matched metals, adhesives, and seals were researched and developed, consistent with sequential firings during sensor assembly. Significant effort was devoted to heater design/testing and to materials' compatibility with Pt electrodes. A systematic approach was taken to develop all sensor components which led to several design modifications. Prototype sensors were constructed and exhaustively tested. It is concluded that development of Nerst-type oxygen sensors based on Bi{sub 2}O{sub 3} will require much further effort and application of specialized technologies. However, during the course of this 3-year program much progress was reported in the literature on amperometric-type oxygen sensors, and a minor effort was devoted here to this type of sensor based on Bi{sub 2}O{sub 3}. These studies were made on Bi{sub 2}O{sub 3}-based ceramic samples in a multilayer-capacitor-type geometry and amperometric-type oxygen sensing was demonstrated at very low temperatures ({approximately} 160{degree}C). A central advantage here is that these types of sensors can be mass-produced very inexpensively ({approximately} 20--50 cents per unit). Research is needed, however, to develop an optimum diffusion-limiting barrier coating. In summary, the original goals of this program were not achieved due to unforeseen problems with Bi{sub 2}O{sub 3}-based Nernst sensors. However, a miniature amperometric sensor base on Bi{sub 2}O{sub 3} was demonstrated in this program, and it is now seen that this latter sensor is far superior to the originally proposed Nernst sensor. 6 refs., 24 figs.

  9. Evolution and physiology of neural oxygen sensing.

    PubMed

    Costa, Kauê M; Accorsi-Mendonça, Daniela; Moraes, Davi J A; Machado, Benedito H

    2014-01-01

    Major evolutionary trends in animal physiology have been heavily influenced by atmospheric O2 levels. Amongst other important factors, the increase in atmospheric O2 which occurred in the Pre-Cambrian and the development of aerobic respiration beckoned the evolution of animal organ systems that were dedicated to the absorption and transportation of O2, e.g., the respiratory and cardiovascular systems of vertebrates. Global variations of O2 levels in post-Cambrian periods have also been correlated with evolutionary changes in animal physiology, especially cardiorespiratory function. Oxygen transportation systems are, in our view, ultimately controlled by the brain related mechanisms, which senses changes in O2 availability and regulates autonomic and respiratory responses that ensure the survival of the organism in the face of hypoxic challenges. In vertebrates, the major sensorial system for oxygen sensing and responding to hypoxia is the peripheral chemoreflex neuronal pathways, which includes the oxygen chemosensitive glomus cells and several brainstem regions involved in the autonomic regulation of the cardiovascular system and respiratory control. In this review we discuss the concept that regulating O2 homeostasis was one of the primordial roles of the nervous system. We also review the physiology of the peripheral chemoreflex, focusing on the integrative repercussions of chemoreflex activation and the evolutionary importance of this system, which is essential for the survival of complex organisms such as vertebrates. The contribution of hypoxia and peripheral chemoreflex for the development of diseases associated to the cardiovascular and respiratory systems is also discussed in an evolutionary context. PMID:25161625

  10. Evolution and physiology of neural oxygen sensing

    PubMed Central

    Costa, Kauê M.; Accorsi-Mendonça, Daniela; Moraes, Davi J. A.; Machado, Benedito H.

    2014-01-01

    Major evolutionary trends in animal physiology have been heavily influenced by atmospheric O2 levels. Amongst other important factors, the increase in atmospheric O2 which occurred in the Pre-Cambrian and the development of aerobic respiration beckoned the evolution of animal organ systems that were dedicated to the absorption and transportation of O2, e.g., the respiratory and cardiovascular systems of vertebrates. Global variations of O2 levels in post-Cambrian periods have also been correlated with evolutionary changes in animal physiology, especially cardiorespiratory function. Oxygen transportation systems are, in our view, ultimately controlled by the brain related mechanisms, which senses changes in O2 availability and regulates autonomic and respiratory responses that ensure the survival of the organism in the face of hypoxic challenges. In vertebrates, the major sensorial system for oxygen sensing and responding to hypoxia is the peripheral chemoreflex neuronal pathways, which includes the oxygen chemosensitive glomus cells and several brainstem regions involved in the autonomic regulation of the cardiovascular system and respiratory control. In this review we discuss the concept that regulating O2 homeostasis was one of the primordial roles of the nervous system. We also review the physiology of the peripheral chemoreflex, focusing on the integrative repercussions of chemoreflex activation and the evolutionary importance of this system, which is essential for the survival of complex organisms such as vertebrates. The contribution of hypoxia and peripheral chemoreflex for the development of diseases associated to the cardiovascular and respiratory systems is also discussed in an evolutionary context. PMID:25161625

  11. Biosupercapacitors for powering oxygen sensing devices.

    PubMed

    Kizling, Michal; Draminska, Sylwia; Stolarczyk, Krzysztof; Tammela, Petter; Wang, Zhaohui; Nyholm, Leif; Bilewicz, Renata

    2015-12-01

    A biofuel cell comprising electrodes based on supercapacitive materials - carbon nanotubes and nanocellulose/polypyrrole composite was utilized to power an oxygen biosensor. Laccase Trametes versicolor, immobilized on naphthylated multi walled carbon nanotubes, and fructose dehydrogenase, adsorbed on a porous polypyrrole matrix, were used as the cathode and anode bioelectrocatalysts, respectively. The nanomaterials employed as the supports for the enzymes increased the surface area of the electrodes and provide direct contact with the active sites of the enzymes. The anode modified with the conducting polymer layer exhibited significant pseudocapacitive properties providing superior performance also in the high energy mode, e.g., when switching on/off the powered device. Three air-fructose biofuel cells connected in a series converted chemical energy into electrical giving 2 mW power and open circuit potential of 2V. The biofuel cell system was tested under various externally applied resistances and used as a powering unit for a laboratory designed two-electrode minipotentiostat and a laccase based sensor for oxygen sensing. Best results in terms of long time measurement of oxygen levels were obtained in the pulse mode -45 s for measurement and 15 min for self-recharging of the powering unit. PMID:25960258

  12. Oxygen-sensing under the influence of nitric oxide.

    PubMed

    Berchner-Pfannschmidt, Utta; Tug, Suzan; Kirsch, Michael; Fandrey, Joachim

    2010-03-01

    The transcription factor complex Hypoxia inducible factor 1 (HIF-1) controls the expression of most genes involved in adaptation to hypoxic conditions. Oxygen-dependency is maintained by prolyl- and asparagyl-4-hydroxylases (PHDs/FIH-1) belonging to the superfamily of iron(II) and 2-oxoglutarate dependent dioxygenases. Hydroxylation of the HIF-1alpha subunit by PHDs and FIH-1 leads to its degradation and inactivation. By hydroxylating HIF-1alpha in an oxygen-dependent manner PHDs and FIH-1 function as oxygen-sensing enzymes of HIF signalling. Besides molecular oxygen nitric oxide (NO), a mediator of the inflammatory response, can regulate HIF-1alpha accumulation, HIF-1 activity and HIF-1 dependent target gene expression. Recent studies addressing regulation of HIF-1 by NO revealed a complex and paradoxical picture. Acute exposure of cells to high doses of NO increased HIF-1alpha levels irrespective of the residing oxygen concentration whereas prolonged exposure to NO or low doses of this radical reduced HIF-1alpha accumulation even under hypoxic conditions. Several mechanisms were found to contribute to this paradoxical role of NO in regulating HIF-1. More recent studies support the view that NO regulates HIF-1 by modulating the activity of the oxygen-sensor enzymes PHDs and FIH-1. NO dependent HIF-1alpha accumulation under normoxia was due to direct inhibition of PHDs and FIH-1 most likely by competitive binding of NO to the ferrous iron in the catalytically active center of the enzymes. In contrast, reduced HIF-1alpha accumulation by NO under hypoxia was mainly due to enhanced HIF-1alpha degradation by induction of PHD activity. Three major mechanisms are discussed to be involved in enhancing the PHD activity despite the lack of oxygen: (1) NO mediated induction of a HIF-1 dependent feedback loop leading to newly expressed PHD2 and enhanced nuclear localization, (2) O2-redistribution towards PHDs after inhibition of mitochondrial respiration by NO, (3

  13. Ratiometric oxygen sensing using lanthanide luminescent emitting interfaces.

    PubMed

    Lehr, Joshua; Tropiano, Manuel; Beer, Paul D; Faulkner, Stephen; Davis, Jason J

    2015-11-14

    Herein we describe the first example of a ratiometric lanthanide luminescent oxygen sensing interface. Immobilisation of terbium and europium cyclen complexes on glass substrates was achieved by a novel aryl nitrene photografting approach. The resulting interfaces demonstrated a ratiometric oxygen response between 0 and 0.2 atm partial oxygen pressure. PMID:26376829

  14. Enhanced optical oxygen sensing using a newly synthesized ruthenium complex together with oxygen carriers.

    PubMed

    Ertekin, Kadriye; Kocak, Suleyman; Sabih Ozer, M; Aycan, Sule; Cetinkaya, Bekir

    2003-11-12

    In this article, an emission based, simple and fast method is proposed for the determination of gaseous oxygen. A newly synthesized fluorophore, dichloro-{2,6-bis[1-(4-dimethylamino-phenylimino) ethyl]pyridine}ruthenium(II) has been used for oxygen sensing together with oxygen carrier perfluorochemicals (PFCs) in silicon matrix. It should be noted that the solubility of oxygen in fluorocarbons is about three to ten times large as that observed in the parent hydrocarbons or in water, respectively. Employed PFCs are chemically and biochemically inert, have high dissolution capacities for oxygen, and, once doped into sensing film, considerably enhance the response of sensing agent. PMID:18969220

  15. Nano-Enriched and Autonomous Sensing Framework for Dissolved Oxygen.

    PubMed

    Shehata, Nader; Azab, Mohammed; Kandas, Ishac; Meehan, Kathleen

    2015-01-01

    This paper investigates a nano-enhanced wireless sensing framework for dissolved oxygen (DO). The system integrates a nanosensor that employs cerium oxide (ceria) nanoparticles to monitor the concentration of DO in aqueous media via optical fluorescence quenching. We propose a comprehensive sensing framework with the nanosensor equipped with a digital interface where the sensor output is digitized and dispatched wirelessly to a trustworthy data collection and analysis framework for consolidation and information extraction. The proposed system collects and processes the sensor readings to provide clear indications about the current or the anticipated dissolved oxygen levels in the aqueous media. PMID:26287211

  16. Correlative NAD(P)H-FLIM and oxygen sensing-PLIM for metabolic mapping.

    PubMed

    Kalinina, Sviatlana; Breymayer, Jasmin; Schäfer, Patrick; Calzia, Enrico; Shcheslavskiy, Vladislav; Becker, Wolfgang; Rück, Angelika

    2016-08-01

    Cellular responses to oxygen tension have been studied extensively. Oxygen tension can be determined by considering the phosphorescence lifetime of a phosphorescence sensor. The simultaneous usage of FLIM of coenzymes as NAD(P)H and FAD(+) and PLIM of oxygen sensors could provide information about correlation of metabolic pathways and oxygen tension. We investigated correlative NAD(P)H-FLIM and oxygen sensing-PLIM for simultaneously analyzing cell metabolism and oxygen tension. Cell metabolism and pO2 were observed under different hypoxic conditions in squamous carcinoma cell cultures and in complex ex vivo systems. Increased hypoxia induced an increase of the phosphorescence lifetime of Ru(BPY)3 and in most cases a decrease in the lifetime of NAD(P)H which is in agreement to the expected decrease of the protein-bound NAD(P)H during hypoxia. Oxygen was modulated directly in the mitochondrial membrane. Blocking of complex III and accumulation of oxygen could be observed by both the decrease of the phosphorescence lifetime of Ru(BPY)3 and a reduction of the lifetime of NAD(P)H which was a clear indication of acute changes in the redox state of the cells. For the first time simultaneous FLIM/PLIM has been shown to be able to visualize intracellular oxygen tension together with a change from oxidative to glycolytic phenotype. PMID:26990032

  17. Imaging Oxygen Metabolism In Acute Stroke Using MRI

    PubMed Central

    An, Hongyu; Ford, Andria L.; Vo, Katie D.; Liu, Qingwei; Chen, Yasheng; Lee, Jin-Moo; Lin, Weili

    2014-01-01

    The ability to image the ischemic penumbra during hyper-acute stroke promises to identify patients who may benefit from treatment intervention beyond population-defined therapeutic time windows. MR blood oxygenation level dependent (BOLD) contrast imaging has been explored in ischemic stroke. This review provides an overview of several BOLD-based methods, including susceptibility weighted imaging (SWI), R2, R2*, R2′, R2* under oxygen challenge, MR_OEF and MROMI approaches to assess cerebral oxygen metabolism in ischemic stroke. We will review the underlying pathophysiological basis of the imaging approaches, followed by a brief introduction of BOLD contrast. Finally, we will discuss the applications of the BOLD approaches in patients with ischemic stroke. BOLD-based methods hold promise for imaging tissue oxygenation during acute ischemia. Further technical refinement and validation studies in stroke patients against positron emission tomography (PET) measurements are needed. PMID:24707451

  18. Quality assessment of packaged foods by optical oxygen sensing

    NASA Astrophysics Data System (ADS)

    Papkovsky, Dmitri B.; O'Mahony, Fiach C.; Kerry, Joe P.; Ogurtsov, Vladimir I.

    2005-11-01

    A phase-fluorometric oxygen sensor system has been developed, which allows non-destructive measurement of residual oxygen levels in sealed containers such as packaged foods. It operates with disposable solid-state sensors incorporated in each pack, and a portable detector which interrogates with the sensors through a (semi)transparent packaging material. The system has been optimized for packaging applications and validated in small and medium scale trials with different types of food, including MAP hams, cheese, convenience foods, smoked fish, bakery. It has demonstrated high efficiency in monitoring package integrity, oxygen profiles in packs, performance of packaging process and many other research and quality control tasks, allowing control of 100% of packs. The low-cost batch-calibrated sensors have demonstrated reliability, safety, stability including direct contact with food, high efficiency in the low oxygen range. Another system, which also employs the fluorescence-based oxygen sensing approach, provides rapid assessment of microbial contamination (total viable counts) in complex samples such as food homogenates, industrial waste, environmental samples, etc. It uses soluble oxygen-sensitive probes, standard microtitter plates and fluorescence measurements on conventional plate reader to monitor growth of aerobic bacteria in small test samples (e.g. food homogenates) via their oxygen respiration. The assay provides high sample through put, miniaturization, speed, and can serve as alternative to the established methods such as agar plate colony counts and turbidimetry.

  19. [Normobaric oxygen therapy in acute medical care: myths versus reality].

    PubMed

    von Düring, Stephan; Bruchez, Stéphanie; Suppan, Laurent; Niquille, Marc

    2015-08-12

    Oxygen adiministration for both medical and traumatic emergencies is regarded as an essential component of resuscitation. However, many recent studies suggest that the use of oxygen should be more restrictive. Detrimental effects of normobaric oxygen therapy in patients suffering from hypercapnic respiratory diseases have been demonstrated, especially because of the suppression of the hypoxic drive. Apart from this particular situation, correction of hypoxemia is still a widely accepted treatment target, although there is growing evidence that hyperoxemia could be harmful in acute coronary syndromes and cardio-respiratory arrests. In other pathologies, such as stroke or hemorragic shock, the situation is still unclear, and further studies are needed to clarify the situation. Generally speaking, oxygen therapy should from now on be goal-directed, and early monitoring of both pulse oximetry and arterial blood gases is advised. PMID:26449100

  20. Oxygen therapy in acute exacerbations of chronic obstructive pulmonary disease

    PubMed Central

    Brill, Simon E; Wedzicha, Jadwiga A

    2014-01-01

    Acute exacerbations of chronic obstructive pulmonary disease (COPD) are important events in the history of this debilitating lung condition. Associated health care utilization and morbidity are high, and many patients require supplemental oxygen or ventilatory support. The last 2 decades have seen a substantial increase in our understanding of the best way to manage the respiratory failure suffered by many patients during this high-risk period. This review article examines the evidence underlying supplemental oxygen therapy during exacerbations of COPD. We first discuss the epidemiology and pathophysiology of respiratory failure in COPD during exacerbations. The rationale and evidence underlying oxygen therapy, including the risks when administered inappropriately, are then discussed, along with further strategies for ventilatory support. We also review current recommendations for best practice, including methods for improving oxygen provision in the future. PMID:25404854

  1. Acute pulmonary edema secondary to hyperbaric oxygen therapy.

    PubMed

    Obiagwu, Chukwudi; Paul, Vishesh; Chadha, Sameer; Hollander, Gerald; Shani, Jacob

    2015-02-01

    Hyperbaric oxygen therapy (HBOT) has been shown to be effective in the treatment of diabetic ulcers, air embolism, carbon monoxide poisoning and gas gangrene with minimal adverse effects. Very few cases of HBOT causing acute pulmonary edema (PE) has been described; with a study on dogs suggesting that a complication of this therapy could be PE. We describe the case of an 80-year-old man with a history of stable systolic heart failure and diabetes mellitus presenting with acute PE following treatment with HBOT for diabetic foot. PMID:25988073

  2. Acute pulmonary edema secondary to hyperbaric oxygen therapy

    PubMed Central

    Obiagwu, Chukwudi; Paul, Vishesh; Chadha, Sameer; Hollander, Gerald; Shani, Jacob

    2015-01-01

    Hyperbaric oxygen therapy (HBOT) has been shown to be effective in the treatment of diabetic ulcers, air embolism, carbon monoxide poisoning and gas gangrene with minimal adverse effects. Very few cases of HBOT causing acute pulmonary edema (PE) has been described; with a study on dogs suggesting that a complication of this therapy could be PE. We describe the case of an 80-year-old man with a history of stable systolic heart failure and diabetes mellitus presenting with acute PE following treatment with HBOT for diabetic foot. PMID:25988073

  3. On a magnetic-luminescent nanocomposite for oxygen sensing application: Construction, characterization and sensing performance.

    PubMed

    Chen, Tieyu; Dai, Henry; Peng, Xing

    2015-11-01

    This paper was devoted to the construction of a magnetic-luminescence nanocomposite for oxygen sensing application, where superparamagnetic Fe3O4 and silica molecular sieve MCM-41 were chosen as the inner core and the outer shell, respectively. A Ru(II) complex was grafted into MCM-41 shell through a coupling ligand N1-(5H-cyclopenta[1,2-b:5,4-b']dipyridin-5-ylidene)benzene-1,4-diamine (denoted as Dafo-Ph-NH2). The final composite was analyzed by electron microscope images, XRD, IR spectra, thermogravimetry and N2 adsorption/desorption. Oxygen sensing performance of this composite was evaluated. Sensitivity of 5.8 (the ratio of emission intensity in pure N2 to that in pure O2) and response time of 16s were obtained with good photostability. PMID:26099825

  4. Acute oxygen therapy: a review of prescribing and delivery practices

    PubMed Central

    Cousins, Joyce L; Wark, Peter AB; McDonald, Vanessa M

    2016-01-01

    Oxygen is a commonly used drug in the clinical setting and like other drugs its use must be considered carefully. This is particularly true for those patients who are at risk of type II respiratory failure in whom the risk of hypercapnia is well established. In recent times, several international bodies have advocated for the prescription of oxygen therapy in an attempt to reduce this risk in vulnerable patient groups. Despite this guidance, published data have demonstrated that there has been poor uptake of these recommendations. Multiple interventions have been tested to improve concordance, and while some of these interventions show promise, the sustainability of these interventions are less convincing. In this review, we summarize data that have been published on the prevalence of oxygen prescription and the accurate and appropriate administration of this drug therapy. We also identify strategies that have shown promise in facilitating changes to oxygen prescription and delivery practice. There is a clear need to investigate the barriers, facilitators, and attitudes of clinicians in relation to the prescription of oxygen therapy in acute care. Interventions based on these findings then need to be designed and tested to facilitate the application of evidence-based guidelines to support sustained changes in practice, and ultimately improve patient care. PMID:27307722

  5. Acute oxygen therapy: a review of prescribing and delivery practices.

    PubMed

    Cousins, Joyce L; Wark, Peter A B; McDonald, Vanessa M

    2016-01-01

    Oxygen is a commonly used drug in the clinical setting and like other drugs its use must be considered carefully. This is particularly true for those patients who are at risk of type II respiratory failure in whom the risk of hypercapnia is well established. In recent times, several international bodies have advocated for the prescription of oxygen therapy in an attempt to reduce this risk in vulnerable patient groups. Despite this guidance, published data have demonstrated that there has been poor uptake of these recommendations. Multiple interventions have been tested to improve concordance, and while some of these interventions show promise, the sustainability of these interventions are less convincing. In this review, we summarize data that have been published on the prevalence of oxygen prescription and the accurate and appropriate administration of this drug therapy. We also identify strategies that have shown promise in facilitating changes to oxygen prescription and delivery practice. There is a clear need to investigate the barriers, facilitators, and attitudes of clinicians in relation to the prescription of oxygen therapy in acute care. Interventions based on these findings then need to be designed and tested to facilitate the application of evidence-based guidelines to support sustained changes in practice, and ultimately improve patient care. PMID:27307722

  6. Oxygen-sensing by arterial chemoreceptors: Mechanisms and medical translation.

    PubMed

    López-Barneo, José; Ortega-Sáenz, Patricia; González-Rodríguez, Patricia; Fernández-Agüera, M Carmen; Macías, David; Pardal, Ricardo; Gao, Lin

    2016-01-01

    Acute O2 sensing is necessary for the activation of cardiorespiratory reflexes (hyperventilation and sympathetic activation), which permit the survival of individuals under hypoxic environments (e.g. high altitude) or medical conditions presenting with reduced capacity for gas exchange between the lung alveoli and the blood. Changes in blood O2 tension are detected by the arterial chemoreceptors, in particular the carotid body (CB), which act in concert with the adrenal medulla (AM) to facilitate rapid adaptations to hypoxia. The field of arterial chemoreception has undergone a considerable expansion in recent years, with many of the fundamental observations made at the molecular and cellular levels serving to improve our understanding of the pathogenesis of numerous medical disorders, and even to propose advances in the treatment strategies. In this review, after a short historical preface, we describe the current model of chemosensory transduction based on the modulation of membrane K(+) channels by O2 in specialized chemoreceptor cells. Recent progress in elucidating the molecular mechanisms underlying the modulation of ion channels by O2 tension, which involves mitochondrial complex I, is also discussed. The discovery in the last few years of a specific population of neural crest-derived stem cells in the CB explains the reversible growth of this organ, an intriguing and unusual property of this type of neuronal tissue that contributes to acclimatization under chronic hypoxia. The essential homeostatic role of the CB-AM axis is clearly evident in newly generated mouse models that reach adulthood, albeit with CB and AM atrophy. These animals exhibit a marked intolerance to even mild hypoxia. CB inhibition or over-activation can have important medical consequences. Respiratory depression by general anesthetics or by opioid use is a common clinical condition that frequently causes death in susceptible individuals. An exaggerated sympathetic outflow due to over

  7. Reactive oxygen species in eradicating acute myeloid leukemic stem cells

    PubMed Central

    Zhang, Hui; Fang, Hai

    2014-01-01

    Leukemic stem cells (LSCs) have been proven to drive leukemia initiation, progression and relapse, and are increasingly being used as a critical target for therapeutic intervention. As an essential feature in LSCs, reactive oxygen species (ROS) homeostasis has been extensively exploited in the past decade for targeting LSCs in acute myeloid leukemia (AML). Most, if not all, agents that show therapeutic benefits are able to alter redox status by inducing ROS, which confers selectivity in eradicating AML stem cells but sparing normal counterparts. In this review, we provide the comprehensive update of ROS-generating agents in the context of their impacts on our understanding of the pathogenesis of AML and its therapy. We anticipate that further characterizing these ROS agents will help us combat against AML in the coming era of LSC-targeting strategy.

  8. Oxygen Sensing Neurons and Neuropeptides Regulate Survival after Anoxia in Developing C. elegans

    PubMed Central

    Flibotte, John J.; Jablonski, Angela M.; Kalb, Robert G.

    2014-01-01

    Hypoxic brain injury remains a major source of neurodevelopmental impairment for both term and preterm infants. The perinatal period is a time of rapid transition in oxygen environments and developmental resetting of oxygen sensing. The relationship between neural oxygen sensing ability and hypoxic injury has not been studied. The oxygen sensing circuitry in the model organism C. elegans is well understood. We leveraged this information to investigate the effects of impairments in oxygen sensing on survival after anoxia. There was a significant survival advantage in developing worms specifically unable to sense oxygen shifts below their preferred physiologic range via genetic ablation of BAG neurons, which appear important for conferring sensitivity to anoxia. Oxygen sensing that is mediated through guanylate cyclases (gcy-31, 33, 35) is unlikely to be involved in conferring this sensitivity. Additionally, animals unable to process or elaborate neuropeptides displayed a survival advantage after anoxia. Based on these data, we hypothesized that elaboration of neuropeptides by BAG neurons sensitized animals to anoxia, but further experiments indicate that this is unlikely to be true. Instead, it seems that neuropeptides and signaling from oxygen sensing neurons operate through independent mechanisms, each conferring sensitivity to anoxia in wild type animals. PMID:24967811

  9. Oxygen sensing by the carotid body: mechanisms and role in adaptation to hypoxia.

    PubMed

    López-Barneo, José; González-Rodríguez, Patricia; Gao, Lin; Fernández-Agüera, M Carmen; Pardal, Ricardo; Ortega-Sáenz, Patricia

    2016-04-15

    Oxygen (O2) is fundamental for cell and whole-body homeostasis. Our understanding of the adaptive processes that take place in response to a lack of O2(hypoxia) has progressed significantly in recent years. The carotid body (CB) is the main arterial chemoreceptor that mediates the acute cardiorespiratory reflexes (hyperventilation and sympathetic activation) triggered by hypoxia. The CB is composed of clusters of cells (glomeruli) in close contact with blood vessels and nerve fibers. Glomus cells, the O2-sensitive elements in the CB, are neuron-like cells that contain O2-sensitive K(+)channels, which are inhibited by hypoxia. This leads to cell depolarization, Ca(2+)entry, and the release of transmitters to activate sensory fibers terminating at the respiratory center. The mechanism whereby O2modulates K(+)channels has remained elusive, although several appealing hypotheses have been postulated. Recent data suggest that mitochondria complex I signaling to membrane K(+)channels plays a fundamental role in acute O2sensing. CB activation during exposure to low Po2is also necessary for acclimatization to chronic hypoxia. CB growth during sustained hypoxia depends on the activation of a resident population of stem cells, which are also activated by transmitters released from the O2-sensitive glomus cells. These advances should foster further studies on the role of CB dysfunction in the pathogenesis of highly prevalent human diseases. PMID:26764048

  10. Oxygen Sensing by Arterial Chemoreceptors Depends on Mitochondrial Complex I Signaling.

    PubMed

    Fernández-Agüera, M Carmen; Gao, Lin; González-Rodríguez, Patricia; Pintado, C Oscar; Arias-Mayenco, Ignacio; García-Flores, Paula; García-Pergañeda, Antonio; Pascual, Alberto; Ortega-Sáenz, Patricia; López-Barneo, José

    2015-11-01

    O2 sensing is essential for mammalian homeostasis. Peripheral chemoreceptors such as the carotid body (CB) contain cells with O2-sensitive K(+) channels, which are inhibited by hypoxia to trigger fast adaptive cardiorespiratory reflexes. How variations of O2 tension (PO2) are detected and the mechanisms whereby these changes are conveyed to membrane ion channels have remained elusive. We have studied acute O2 sensing in conditional knockout mice lacking mitochondrial complex I (MCI) genes. We inactivated Ndufs2, which encodes a protein that participates in ubiquinone binding. Ndufs2-null mice lose the hyperventilatory response to hypoxia, although they respond to hypercapnia. Ndufs2-deficient CB cells have normal functions and ATP content but are insensitive to changes in PO2. Our data suggest that chemoreceptor cells have a specialized succinate-dependent metabolism that induces an MCI state during hypoxia, characterized by the production of reactive oxygen species and accumulation of reduced pyridine nucleotides, which signal neighboring K(+) channels. PMID:26437605

  11. Mechanisms of oxygen sensing: a key to therapy of pulmonary hypertension and patent ductus arteriosus

    PubMed Central

    Weir, E K; Obreztchikova, M; Vargese, A; Cabrera, J A; Peterson, D A; Hong, Z

    2008-01-01

    Specialized tissues that sense acute changes in the local oxygen tension include type 1 cells of the carotid body, neuroepithelial bodies in the lungs, and smooth muscle cells of the resistance pulmonary arteries and the ductus arteriosus (DA). Hypoxia inhibits outward potassium current in carotid body type 1 cells, leading to depolarization and calcium entry through L-type calcium channels. Increased intracellular calcium concentration ([Ca++]i) leads to exocytosis of neurotransmitters, thus stimulating the carotid sinus nerve and respiration. The same K+ channel inhibition occurs with hypoxia in pulmonary artery smooth muscle cells (PASMCs), causing contraction and providing part of the mechanism of hypoxic pulmonary vasoconstriction (HPV). In the SMCs of the DA, the mechanism works in reverse. It is the shift from hypoxia to normoxia that inhibits K+ channels and causes normoxic ductal contraction. In both PA and DA, the contraction is augmented by release of Ca++ from the sarcoplasmic reticulum, entry of Ca++ through store-operated channels (SOC) and by Ca++ sensitization. The same three ‘executive' mechanisms are partly responsible for idiopathic pulmonary arterial hypertension (IPAH). While vasoconstrictor mediators constrict both PA and DA and vasodilators dilate both vessels, only redox changes mimic oxygen by having directly opposite effects on the K+ channels, membrane potential, [Ca++]i and tone in the PA and DA. There are several different hypotheses as to how redox might alter tone, which remain to be resolved. However, understanding the mechanism will facilitate drug development for pulmonary hypertension and patent DA. PMID:18641675

  12. Oxygen scrubbing and sensing in plant growth chambers using solid oxide electrolyzers

    NASA Technical Reports Server (NTRS)

    Sridhar, K. R.; MacElroy, Robert D.

    1997-01-01

    The maintenance of optimal levels of oxygen in the gaseous environment of a plant growth chamber during light and dark periods is an essential criterion for the correct growth of plants. The use of solid oxide electrolyzers to control the oxygen levels by removing the excess gaseous oxygen during periods of illumination and full-scale photosynthesis is described. A part of the oxygen removed can be stored and supplied back to the plants during dark periods. The excess oxygen can be used by the crew. The electrolizer can be additionally used in its open circuit mode, to sense the oxygen concentrations in the plant chamber. The solid oxide electrolysis process is described.

  13. Hyperbaric Oxygen Therapy in Acute Ischemic Stroke: A Review

    PubMed Central

    Ding, Zheng; Tong, Wesley C.; Lu, Xiao-Xin; Peng, Hui-Ping

    2014-01-01

    Stroke, also known as cerebrovascular disease, is a common and serious neurological disease, which is also the fourth leading cause of death in the United States so far. Hyperbaric medicine, as an emerging interdisciplinary subject, has been applied in the treatment of cerebral vascular diseases since the 1960s. Now it is widely used to treat a variety of clinical disorders, especially hypoxia-induced disorders. However, owing to the complex mechanisms of hyperbaric oxygen (HBO) treatment, the therapeutic time window and the undefined dose as well as some common clinical side effects (such as middle ear barotrauma), the widespread promotion and application of HBO was hindered, slowing down the hyperbaric medicine development. In August 2013, the US Food and Drug Administration declared artery occlusion as one of the 13 specific indications for HBO therapy. This provides opportunities, to some extent, for the further development of hyperbaric medicine. Currently, the mechanisms of HBO therapy for ischemic stroke are still not very clear. This review focuses on the potential mechanisms of HBO therapy in acute ischemic stroke as well as the time window. PMID:25337089

  14. A plastic optical fiber sensor for the dual sensing of temperature and oxygen

    NASA Astrophysics Data System (ADS)

    Lo, Yu-Lung; Chu, Chen-Shane

    2008-04-01

    This study presents a low-cost plastic optical fiber sensor for the dual sensing of temperature and oxygen. The sensor features a commercially available epoxy glue coated on the side-polished fiber surface for temperature sensing and a fluorinated xerogel doped with platinum tetrakis pentrafluoropheny porphine (PtTFPP) coated on the fiber end for oxygen sensing. The temperature and oxygen indicators are both excited using a UV LED light source with a wavelength of 380 nm. The luminescence emission spectra of the two indicators are well resolved and exhibit no cross-talk effects. Overall, the results indicate that the dual sensor presented in this study provides an ideal solution for the non-contact, simultaneous sensing of temperature and oxygen in general biological and medical applications.

  15. Modulation of Perfusion and Oxygenation by Red Blood Cell Oxygen Affinity during Acute Anemia

    PubMed Central

    Cabrales, Pedro; Tsai, Amy G.; Intaglietta, Marcos

    2008-01-01

    Responses to exchange transfusion using red blood cells (RBCs) with modified hemoglobin (Hb) oxygen (O2) affinity were studied in the hamster window chamber model during acute anemia to determine its role on microvascular perfusion and tissue oxygenation. Allosteric effectors were introduced in the RBCs by electroporation. Inositol hexaphosphate (IHP) and 5-hydroxymethyl-2-furfural (5HMF) were used to decrease and increase Hb-O2 affinity. In vitro P50s (partial pressure of O2 at 50% Hb saturation) were modified to 10, 25, 45, and 50 mm Hg (normal P50 is 32 mm Hg). Allosteric effectors also decreased the Hill coefficient. Anemic condition was induced by isovolemic hemodilution exchanges using 6% dextran 70 kD to 18% hematocrit (Hct). Modified RBCs (at 18% Hct in 5% albumin solution) were infused by exchange transfusion of 35% of blood volume. Systemic parameters, microvascular perfusion, capillary perfusion (functional capillary density, FCD), and microvascular Po2 levels were measured. RBcs with P50 of 45 mm Hg increased tissue Po2 and decreased O2 delivery (Do2) and extraction (Vo2) and RBCs with P50 of 60 mmHg reduced FCD, microvascular flow, tissue Po2, Do2 and Vo2. Erythrocytes with increased Hb-O2 affinity maintained hemodynamic conditions, Do2 and decreased tissue Po2. This study shows that in an anemic condition, maximal tissue Po2 does not correspond to maximal Do2 and Vo2. PMID:17884988

  16. Distributed Fiber Optical Sensing of Oxygen with Optical Time Domain Reflectometry

    PubMed Central

    Eich, Susanne; Schmälzlin, Elmar; Löhmannsröben, Hans-Gerd

    2013-01-01

    In many biological and environmental applications spatially resolved sensing of molecular oxygen is desirable. A powerful tool for distributed measurements is optical time domain reflectometry (OTDR) which is often used in the field of telecommunications. We combine this technique with a novel optical oxygen sensor dye, triangular-[4] phenylene (TP), immobilized in a polymer matrix. The TP luminescence decay time is 86 ns. The short decay time of the sensor dye is suitable to achieve a spatial resolution of some meters. In this paper we present the development and characterization of a reflectometer in the UV range of the electromagnetic spectrum as well as optical oxygen sensing with different fiber arrangements. PMID:23727953

  17. A Microfluidic Device for Continuous Sensing of Systemic Acute Toxicants in Drinking Water

    PubMed Central

    Zhao, Xinyan; Dong, Tao

    2013-01-01

    A bioluminescent-cell-based microfluidic device for sensing toxicants in drinking water was designed and fabricated. The system employed Vibrio fischeri cells as broad-spectrum sensors to monitor potential systemic cell toxicants in water, such as heavy metal ions and phenol. Specifically, the chip was designed for continuous detection. The chip design included two counter-flow micromixers, a T-junction droplet generator and six spiral microchannels. The cell suspension and water sample were introduced into the micromixers and dispersed into droplets in the air flow. This guaranteed sufficient oxygen supply for the cell sensors. Copper (Cu2+), zinc (Zn2+), potassium dichromate and 3,5-dichlorophenol were selected as typical toxicants to validate the sensing system. Preliminary tests verified that the system was an effective screening tool for acute toxicants although it could not recognize or quantify specific toxicants. A distinct non-linear relationship was observed between the zinc ion concentration and the Relative Luminescence Units (RLU) obtained during testing. Thus, the concentration of simple toxic chemicals in water can be roughly estimated by this system. The proposed device shows great promise for an early warning system for water safety. PMID:24300075

  18. A rhenium complex doped in a silica molecular sieve for molecular oxygen sensing: Construction and characterization.

    PubMed

    Yang, Xiaozhou; Li, Yanxiao

    2016-01-15

    This paper reported a diamine ligand and its Re(I) complex for potential application in oxygen sensing. The novelty of this diamine ligand localized at its increased conjugation chain which had a typical electron-withdrawing group of 1,3,4-oxadiazole. Electronic distribution of excited electrons and their lifetime were supposed to be increased, favoring oxygen sensing collision. This hypothesis was confirmed by single crystal analysis, theoretical calculation and photophysical measurement. It was found that this Re(I) complex had a long-lived emission peaking at 545 nm, favoring sensing application. By doping this complex into a silica matrix MCM-41, oxygen sensing performance and mechanism of the resulting composites were discussed in detail. Non-linear Stern-Volmer working curves were observed with maximum sensitivity of 5.54 and short response time of ~6 s. PMID:26478986

  19. A rhenium complex doped in a silica molecular sieve for molecular oxygen sensing: Construction and characterization

    NASA Astrophysics Data System (ADS)

    Yang, Xiaozhou; Li, Yanxiao

    2016-01-01

    This paper reported a diamine ligand and its Re(I) complex for potential application in oxygen sensing. The novelty of this diamine ligand localized at its increased conjugation chain which had a typical electron-withdrawing group of 1,3,4-oxadiazole. Electronic distribution of excited electrons and their lifetime were supposed to be increased, favoring oxygen sensing collision. This hypothesis was confirmed by single crystal analysis, theoretical calculation and photophysical measurement. It was found that this Re(I) complex had a long-lived emission peaking at 545 nm, favoring sensing application. By doping this complex into a silica matrix MCM-41, oxygen sensing performance and mechanism of the resulting composites were discussed in detail. Non-linear Stern-Volmer working curves were observed with maximum sensitivity of 5.54 and short response time of ~ 6 s.

  20. A Pyrene@Micelle Sensor for Fluorescent Oxygen Sensing

    PubMed Central

    Yuan, Yan-xia; Peng, Hong-shang; Ping, Jian-tao; Wang, Xiao-hui; You, Fang-tian

    2015-01-01

    For most fluorescent oxygen sensors developed today, their fabrication process is either time-consuming or needs specialized knowledge. In this work, a robust fluorescent oxygen sensor is facilely constructed by dissolving pyrene molecules into CTAB aqueous solution. The as-prepared pyrene@micelle sensors have submicron-sized diameter, and the concentration of utilized pyrene can be reduced as low as 0.8 mM but still can exhibit dominant excimer emission. The excimer fluorescence is sensitive to dissolved oxygen in both intensity and lifetime, and the respective Stern-Volmer plot follows a nonlinear behavior justified by a two-site model. Because of the merits of large Stokes shift (~140 nm), easy fabrication, and robustness, the pyrene@micelle sensors are very attractive for practical determination of oxygen. PMID:26539471

  1. Luminescent sensing and imaging of oxygen: fierce competition to the Clark electrode.

    PubMed

    Wolfbeis, Otto S

    2015-08-01

    Luminescence-based sensing schemes for oxygen have experienced a fast growth and are in the process of replacing the Clark electrode in many fields. Unlike electrodes, sensing is not limited to point measurements via fiber optic microsensors, but includes additional features such as planar sensing, imaging, and intracellular assays using nanosized sensor particles. In this essay, I review and discuss the essentials of (i) common solid-state sensor approaches based on the use of luminescent indicator dyes and host polymers; (ii) fiber optic and planar sensing schemes; (iii) nanoparticle-based intracellular sensing; and (iv) common spectroscopies. Optical sensors are also capable of multiple simultaneous sensing (such as O2 and temperature). Sensors for O2 are produced nowadays in large quantities in industry. Fields of application include sensing of O2 in plant and animal physiology, in clinical chemistry, in marine sciences, in the chemical industry and in process biotechnology. PMID:26113255

  2. Luminescent sensing and imaging of oxygen: Fierce competition to the Clark electrode

    PubMed Central

    2015-01-01

    Luminescence‐based sensing schemes for oxygen have experienced a fast growth and are in the process of replacing the Clark electrode in many fields. Unlike electrodes, sensing is not limited to point measurements via fiber optic microsensors, but includes additional features such as planar sensing, imaging, and intracellular assays using nanosized sensor particles. In this essay, I review and discuss the essentials of (i) common solid‐state sensor approaches based on the use of luminescent indicator dyes and host polymers; (ii) fiber optic and planar sensing schemes; (iii) nanoparticle‐based intracellular sensing; and (iv) common spectroscopies. Optical sensors are also capable of multiple simultaneous sensing (such as O2 and temperature). Sensors for O2 are produced nowadays in large quantities in industry. Fields of application include sensing of O2 in plant and animal physiology, in clinical chemistry, in marine sciences, in the chemical industry and in process biotechnology. PMID:26113255

  3. Mechanisms of sensing and adaptive responses to low oxygen conditions in mammals and yeasts.

    PubMed

    Trendeleva, T A; Aliverdieva, D A; Zvyagilskaya, R A

    2014-08-01

    Oxygen is required for effective production of ATP and plays a key role in the maintenance of life for all organisms, excepting strict anaerobes. The ability of aerobic organisms to sense and respond to changes in oxygen level is a basic requirement for their survival. Eukaryotes have developed adaptive mechanisms to sense and respond to decreased oxygen concentrations (hypoxia) through adjustment of oxygen homeostasis by upregulating hypoxic and downregulating aerobic nuclear genes. This review summarizes recent data on mechanisms of cells sensing and responding to changes in oxygen availability in mammals and in yeasts. In the first part of the review, prominence is given to functional regulation and stabilization of hypoxia-inducible factors (HIFs), HIF-mediated regulation of electron transport flux and repression of lipogenesis, as well as to hypoxia-induced mitochondrial permeability transition (pore) opening, cell death, and autophagy. In the second part of the review emphasis is placed on oxygen sensing in nonpathogenic yeasts by heme, unsaturated fatty acids, and sterols, as well as on responses to hypoxia in fungal pathogens. PMID:25365485

  4. The role of high flow oxygen therapy in acute respiratory failure.

    PubMed

    Masclans, J R; Pérez-Terán, P; Roca, O

    2015-11-01

    Acute respiratory failure represents one of the most common causes of intensive care unit admission and oxygen therapy remains the first-line therapy in the management of these patients. In recent years, high-flow oxygen via nasal cannula has been described as a useful alternative to conventional oxygen therapy in patients with acute respiratory failure. High-flow oxygen via nasal cannula rapidly alleviates symptoms of acute respiratory failure and improves oxygenation by several mechanisms, including dead space washout, reduction in oxygen dilution and inspiratory nasopharyngeal resistance, a moderate positive airway pressure effect that may generate alveolar recruitment and an overall greater tolerance and comfort with the interface and the heated and humidified inspired gases. However, the experience in adults is still limited and there are no clinical guidelines to establish recommendations for their use. This article aims to review the existing evidence on the use of high-flow oxygen via nasal cannula in adults with acute respiratory failure and its possible applications, advantages and limitations. PMID:26429697

  5. Morphology impact on oxygen sensing ability of Ru(dpp)3Cl2 containing biocompatible polymers.

    PubMed

    Zhao, Susan Y; Harrison, Benjamin S

    2015-08-01

    Especially for tissue engineering applications, the diffusion of oxygen is a critical factor affecting spatial distribution and migration of cells. The cellular oxygen demand also fluctuates depending on tissue type and growth phase. Sensors that determine dissolved oxygen levels under biological conditions provide critical metabolic information about the growing cells as well as the state of the tissue culture within the tissue scaffold. This work focused on the effect of the scaffold morphology on the oxygen sensing response time. It was found that electrospun scaffolds had a faster oxygen-sensing response time than their bulk film counterparts. Tris-(4,7-diphenyl-1,10-phenanthroline) ruthenium (II) dichloride doped electrospun fiber mats of polycaprolactone (PCL) were found to be the most responsive to the presence of oxygen, followed by polyethylene (PEO) glycol mats. Systems containing poly vinyl alcohol were found to be the least responsive. This would suggest that, out of all the polymers tested, PCL and PEO are the most suitable biomaterials for oxygen-sensing applications. PMID:26042716

  6. Intrarenal and urinary oxygenation during norepinephrine resuscitation in ovine septic acute kidney injury.

    PubMed

    Lankadeva, Yugeesh R; Kosaka, Junko; Evans, Roger G; Bailey, Simon R; Bellomo, Rinaldo; May, Clive N

    2016-07-01

    Norepinephrine is the principal vasopressor used to restore blood pressure in sepsis, but its effects on intrarenal oxygenation are unknown. To clarify this, we examined renal cortical, medullary, and urinary oxygenation in ovine septic acute kidney injury and the response to resuscitation with norepinephrine. A renal artery flow probe and fiberoptic probes were placed in the cortex and medulla of sheep to measure tissue perfusion and oxygenation. A probe in the bladder catheter measured urinary oxygenation. Sepsis was induced in conscious sheep by infusion of Escherichia coli for 32 hours. At 24 to 30 hours of sepsis, either norepinephrine, to restore mean arterial pressure to preseptic levels or vehicle-saline was infused (8 sheep per group). Septic acute kidney injury was characterized by a reduction in blood pressure of ∼12 mm Hg, renal hyperperfusion, and oliguria. Sepsis reduced medullary perfusion (from an average of 1289 to 628 blood perfusion units), medullary oxygenation (from 32 to 16 mm Hg), and urinary oxygenation (from 36 to 24 mm Hg). Restoring blood pressure with norepinephrine further reduced medullary perfusion to an average of 331 blood perfusion units, medullary oxygenation to 8 mm Hg and urinary oxygenation to 18 mm Hg. Cortical perfusion and oxygenation were preserved. Thus, renal medullary hypoxia caused by intrarenal blood flow redistribution may contribute to the development of septic acute kidney injury, and resuscitation of blood pressure with norepinephrine exacerbates medullary hypoxia. The parallel changes in medullary and urinary oxygenation suggest that urinary oxygenation may be a useful real-time biomarker for risk of acute kidney injury. PMID:27165831

  7. Role of reactive oxygen and nitrogen species in acute respiratory distress syndrome.

    PubMed

    Fink, Mitchell P

    2002-02-01

    Reactive oxygen species are reactive, partially reduced derivatives of molecular oxygen (O 2 ). Important reactive oxygen species in biologic systems include superoxide radical anion, hydrogen peroxide, and hydroxyl radical. Closely related species include the hypohalous acids, particularly hypochlorous acid; chloramine and substituted chloramines; and singlet oxygen. Reactive nitrogen species are derived from the simple diatomic gas, nitric oxide. Peroxynitrite and its protonated form, peroxynitrous acid, are the most significant reactive nitrogen species in biologic systems. A variety of enzymatic and nonenzymatic processes can generate reactive oxygen species and reactive nitrogen species in mammalian cells. An extensive body of experimental evidence from studies using animal models supports the view that reactive oxygen species and reactive nitrogen species are important in the pathogenesis of acute respiratory distress syndrome. This view is further supported by data from clinical studies that correlate biochemical evidence of reactive oxygen species-mediated or reactive nitrogen species-mediated stress with the development of acute respiratory distress syndrome. Despite these data, pharmacologic strategies directed at minimizing reactive oxygen species-mediated or reactive nitrogen species-mediated damage have yet to be successfully introduced into clinical practice. The most extensively studied compound in this regard is N -acetylcysteine; unfortunately, clinical trials with this compound in patients with acute respiratory distress syndrome have yielded disappointing results. PMID:12205400

  8. Spatiotemporal Oxygen Sensing Using Dual Emissive Boron Dye–Polylactide Nanofibers

    PubMed Central

    2015-01-01

    Oxygenation in tissue scaffolds continues to be a limiting factor in regenerative medicine despite efforts to induce neovascularization or to use oxygen-generating materials. Unfortunately, many established methods to measure oxygen concentration, such as using electrodes, require mechanical disturbance of the tissue structure. To address the need for scaffold-based oxygen concentration monitoring, a single-component, self-referenced oxygen sensor was made into nanofibers. Electrospinning process parameters were tuned to produce a biomaterial scaffold with specific morphological features. The ratio of an oxygen sensitive phosphorescence signal to an oxygen insensitive fluorescence signal was calculated at each image pixel to determine an oxygenation value. A single component boron dye–polymer conjugate was chosen for additional investigation due to improved resistance to degradation in aqueous media compared to a boron dye polymer blend. Standardization curves show that in fully supplemented media, the fibers are responsive to dissolved oxygen concentrations less than 15 ppm. Spatial (millimeters) and temporal (minutes) ratiometric gradients were observed in vitro radiating outward from the center of a dense adherent cell grouping on scaffolds. Sensor activation in ischemia and cell transplant models in vivo show oxygenation decreases on the scale of minutes. The nanofiber construct offers a robust approach to biomaterial scaffold oxygen sensing. PMID:25426706

  9. Development of oxygen sensing in the gills of zebrafish.

    PubMed

    Jonz, Michael G; Nurse, Colin A

    2005-04-01

    Previous studies have described the morphology, innervation and O(2)-chemoreceptive properties of neuroepithelial cells (NECs) of the zebrafish gill filaments. The present work describes the ontogenesis of these cells, and the formation of functional O(2)-sensing pathways in developing zebrafish. Confocal immunofluorescence was performed on whole-mount gill preparations using antibodies against serotonin (5-HT) and a zebrafish-derived neuronal marker (zn-12) to identify the appearance and innervation of gill NECs during larval stages. NECs were first expressed in gill filament primordia of larvae at 5 days postfertilization (d.p.f.) and were fully innervated by 7 d.p.f. In vivo ventilation frequency analysis revealed that a behavioural response to hypoxia (11.2+/-2.8 min(-1)) developed in embryos as early as 2 d.p.f., and a significant increase (P<0.05) in the ventilatory response to hypoxia (200.8+/-23.0 min(-1)) coincided with innervation of NECs of the filaments. In addition, exogenous application of quinidine, a blocker of O(2)-sensitive background K(+) channels in NECs, induced hyperventilation in adults in a dose-dependent manner and revealed the development of a quinidine-sensitive ventilatory response in 7 d.p.f. larvae. This study shows that NEC innervation in the gill filaments may account for the development of a functional O(2)-sensing pathway and the hyperventilatory response to hypoxia in zebrafish larvae. At earlier stages, however, O(2)-sensing must occur through another pathway. The possibility that a new type of 5-HT-positive NEC of the gill arches may account for this earlier hypoxic response is discussed. PMID:15802677

  10. Oxygen Sensing for Industrial Safety — Evolution and New Approaches

    PubMed Central

    Willett, Martin

    2014-01-01

    The requirement for the detection of oxygen in industrial safety applications has historically been met by electrochemical technologies based on the consumption of metal anodes. Products using this approach have been technically and commercially successful for more than three decades. However, a combination of new requirements is driving the development of alternative approaches offering fresh opportunities and challenges. This paper reviews some key aspects in the evolution of consumable anode products and highlights recent developments in alternative technologies aimed at meeting current and anticipated future needs in this important application. PMID:24681673

  11. "Oxygen Sensing" by Na,K-ATPase: These Miraculous Thiols.

    PubMed

    Bogdanova, Anna; Petrushanko, Irina Y; Hernansanz-Agustín, Pablo; Martínez-Ruiz, Antonio

    2016-01-01

    Control over the Na,K-ATPase function plays a central role in adaptation of the organisms to hypoxic and anoxic conditions. As the enzyme itself does not possess O2 binding sites its "oxygen-sensitivity" is mediated by a variety of redox-sensitive modifications including S-glutathionylation, S-nitrosylation, and redox-sensitive phosphorylation. This is an overview of the current knowledge on the plethora of molecular mechanisms tuning the activity of the ATP-consuming Na,K-ATPase to the cellular metabolic activity. Recent findings suggest that oxygen-derived free radicals and H2O2, NO, and oxidized glutathione are the signaling messengers that make the Na,K-ATPase "oxygen-sensitive." This very ancient signaling pathway targeting thiols of all three subunits of the Na,K-ATPase as well as redox-sensitive kinases sustains the enzyme activity at the "optimal" level avoiding terminal ATP depletion and maintaining the transmembrane ion gradients in cells of anoxia-tolerant species. We acknowledge the complexity of the underlying processes as we characterize the sources of reactive oxygen and nitrogen species production in hypoxic cells, and identify their targets, the reactive thiol groups which, upon modification, impact the enzyme activity. Structured accordingly, this review presents a summary on (i) the sources of free radical production in hypoxic cells, (ii) localization of regulatory thiols within the Na,K-ATPase and the role reversible thiol modifications play in responses of the enzyme to a variety of stimuli (hypoxia, receptors' activation) (iii) redox-sensitive regulatory phosphorylation, and (iv) the role of fine modulation of the Na,K-ATPase function in survival success under hypoxic conditions. The co-authors attempted to cover all the contradictions and standing hypotheses in the field and propose the possible future developments in this dynamic area of research, the importance of which is hard to overestimate. Better understanding of the processes

  12. Role Of Hif2α Oxygen Sensing Pathway In Bronchial Epithelial Club Cell Proliferation

    PubMed Central

    Torres-Capelli, Mar; Marsboom, Glenn; Li, Qilong Oscar Yang; Tello, Daniel; Rodriguez, Florinda Melendez; Alonso, Tamara; Sanchez-Madrid, Francisco; García-Rio, Francisco; Ancochea, Julio; Aragonés, Julián

    2016-01-01

    Oxygen-sensing pathways executed by the hypoxia-inducible factors (HIFs) induce a cellular adaptive program when oxygen supply becomes limited. However, the role of the HIF oxygen-sensing pathway in the airway response to hypoxic stress in adulthood remains poorly understood. Here we found that in vivo exposure to hypoxia led to a profound increase in bronchial epithelial cell proliferation mainly confined to Club (Clara) cells. Interestingly, this response was executed by hypoxia-inducible factor 2α (HIF2α), which controls the expression of FoxM1, a recognized proliferative factor of Club cells. Furthermore, HIF2α induced the expression of the resistin-like molecules α and β (RELMα and β), previously considered bronchial epithelial growth factors. Importantly, despite the central role of HIF2α, this proliferative response was not initiated by in vivo Vhl gene inactivation or pharmacological inhibition of prolyl hydroxylase oxygen sensors, indicating the molecular complexity of this response and the possible participation of other oxygen-sensing pathways. Club cells are principally involved in protection and maintenance of bronchial epithelium. Thus, our findings identify a novel molecular link between HIF2α and Club cell biology that can be regarded as a new HIF2α-dependent mechanism involved in bronchial epithelium adaptation to oxygen fluctuations. PMID:27150457

  13. Remote sensing of atmospheric oxygen from a sounding rocket

    NASA Technical Reports Server (NTRS)

    Chakrabarti, S.; Cotton, D. M.; Lampton, M.; Siegmund, O. H. W.; Link, R.

    1988-01-01

    This paper describes a rocket experiment to investigate mechanisms governing the interactions between two of the fundamental components of the solar-terrestrial system: the solar ionizing radiation and the earth's upper atmosphere. The aim is to characterize the extreme ultraviolet (EUV) emissions resulting from these interactions in terms of physical parameters so that EUV remote sensing can be gainfully employed as a quantitative diagnostic of the terrestrial atmosphere and plasma environment. The payload consists of a high-resolution (about 0.5 A) spectrometer to measure the EUV emissions (980-1360 A) of the earth's dayglow, a moderate resolution (about 15 A) EUV spectrometer (250-1450 A) to measure the solar irradiation responsible for the photoelectron production, and a hydrogen Lyman Alpha photometer to monitor the solar irradiance and geocoronal emissions.

  14. Erythrocytes Are Oxygen-Sensing Regulators of the Cerebral Microcirculation.

    PubMed

    Wei, Helen Shinru; Kang, Hongyi; Rasheed, Izad-Yar Daniel; Zhou, Sitong; Lou, Nanhong; Gershteyn, Anna; McConnell, Evan Daniel; Wang, Yixuan; Richardson, Kristopher Emil; Palmer, Andre Francis; Xu, Chris; Wan, Jiandi; Nedergaard, Maiken

    2016-08-17

    Energy production in the brain depends almost exclusively on oxidative metabolism. Neurons have small energy reserves and require a continuous supply of oxygen (O2). It is therefore not surprising that one of the hallmarks of normal brain function is the tight coupling between cerebral blood flow and neuronal activity. Since capillaries are embedded in the O2-consuming neuropil, we have here examined whether activity-dependent dips in O2 tension drive capillary hyperemia. In vivo analyses showed that transient dips in tissue O2 tension elicit capillary hyperemia. Ex vivo experiments revealed that red blood cells (RBCs) themselves act as O2 sensors that autonomously regulate their own deformability and thereby flow velocity through capillaries in response to physiological decreases in O2 tension. This observation has broad implications for understanding how local changes in blood flow are coupled to synaptic transmission. PMID:27499087

  15. Oxygen-Sensing Methods in Biomedicine from the Macroscale to the Microscale.

    PubMed

    Roussakis, Emmanuel; Li, Zongxi; Nichols, Alexander J; Evans, Conor L

    2015-07-13

    Oxygen monitoring has been a topic of exhaustive study given its central role in the biochemistry of life. The ability to quantify the physiological distribution and real-time dynamics of oxygen from sub-cellular to macroscopic levels is required to fully understand the mechanisms associated with both normal physiology and disease states. This Review will present the most significant recent advances in the development of oxygen-sensing materials and techniques, including polarographic, nuclear medicine, magnetic resonance, and optical approaches, that can be applied specifically for the real-time monitoring of oxygen dynamics in cellular and tissue environments. As some of the most exciting recent advances in synthetic methods and biomedical applications have been in the field of optical oxygen sensors, a major focus will be on the development of these toolkits. PMID:26084034

  16. Thickness Dependency of Thin Film Samaria Doped Ceria for Oxygen Sensing

    SciTech Connect

    Sanghavi, Rahul P.; Nandasiri, Manjula I.; Kuchibhatla, Satyanarayana V N T; Jiang, Weilin; Varga, Tamas; Nachimuthu, Ponnusamy; Engelhard, Mark H.; Shutthanandan, V.; Thevuthasan, Suntharampillai; Kayani, Asghar N.; Prasad, Shalini

    2011-01-01

    High temperature oxygen sensors are widely used for exhaust gas monitoring in automobiles. This particular study explores the use of thin film single crystalline samaria doped ceria as the oxygen sensing material. Desired signal to noise ratio can be achieved in a material system with high conductivity. From previous studies it is established that 6 atomic percent samarium doping is the optimum concentration for thin film samaria doped ceria to achieve high ionic conductivity. In this study, the conductivity of the 6 atomic percent samaria doped ceria thin film is measured as a function of the sensing film thickness. Hysteresis and dynamic response of this sensing platform is tested for a range of oxygen pressures from 0.001 Torr to 100 Torr for temperatures above 673 K. An attempt has been made to understand the physics behind the thickness dependent conductivity behavior of this sensing platform by developing a hypothetical operating model and through COMSOL simulations. This study can be used to identify the parameters required to construct a fast, reliable and compact high temperature oxygen sensor.

  17. Cellular Oxygen and Nutrient Sensing in Microgravity Using Time-Resolved Fluorescence Microscopy

    NASA Technical Reports Server (NTRS)

    Szmacinski, Henryk

    2003-01-01

    Oxygen and nutrient sensing is fundamental to the understanding of cell growth and metabolism. This requires identification of optical probes and suitable detection technology without complex calibration procedures. Under this project Microcosm developed an experimental technique that allows for simultaneous imaging of intra- and inter-cellular events. The technique consists of frequency-domain Fluorescence Lifetime Imaging Microscopy (FLIM), a set of identified oxygen and pH probes, and methods for fabrication of microsensors. Specifications for electronic and optical components of FLIM instrumentation are provided. Hardware and software were developed for data acquisition and analysis. Principles, procedures, and representative images are demonstrated. Suitable lifetime sensitive oxygen, pH, and glucose probes for intra- and extra-cellular measurements of analyte concentrations have been identified and tested. Lifetime sensing and imaging have been performed using PBS buffer, culture media, and yeast cells as a model systems. Spectral specifications, calibration curves, and probes availability are also provided in the report.

  18. Clinical Research in Acute Fatal Illness: Lessons From Extracorporeal Membrane Oxygenation.

    PubMed

    Bartlett, Robert H

    2016-08-01

    Clinical research to evaluate the effectiveness of life support systems in acute fatal illness has unique problems of logistics, ethics, and consent. There have been 10 prospective comparative trials of extracorporeal membrane oxygenation in acute fatal respiratory failure, utilizing different study designs. The trial designs were prospective controlled randomized, prospective adaptive randomized, sequential, and matched pairs. The trials were reviewed with regard to logistics, ethics, consent, statistical methods, economics, and impact. The matched pairs method is the best study design for evaluation of life support systems in acute fatal illness. PMID:25223826

  19. Acute carbon monoxide poisoning: Emergency management and hyperbaric oxygen therapy

    SciTech Connect

    Severance, H.W.; Kolb, J.C.; Carlton, F.B.; Jorden, R.C.

    1989-10-01

    An ice storm in February 1989 resulted in numerous incidences of carbon monoxide poisoning in central Mississippi secondary to exposure to open fires in unventilated living spaces. Sixteen cases were treated during this period at the University of Mississippi Medical Center and 6 received Hyperbaric Oxygen therapy. These 6 cases and the mechanisms of CO poisoning are discussed and recommendations for emergency management are reviewed.10 references.

  20. ACUTE SENSITIVITY OF JUVENILE SHORTNOSE STURGEON TO LOW DISSOLVED OXYGEN CONCENTRATIONS

    EPA Science Inventory

    Campbell, Jed G. and Larry R. Goodman. 2004. Acute Sensitivity of Juvenile Shortnose Sturgeon to Low Dissolved Oxygen Concentrations. EPA/600/J-04/175. Trans. Am. Fish. Soc. 133(3):772-776. (ERL,GB 1155).

    There is considerable concern that factors such as eutrophication, ...

  1. A mechanism of oxygen sensing in yeast. Multiple oxygen-responsive steps in the heme biosynthetic pathway affect Hap1 activity.

    PubMed

    Hon, Thomas; Dodd, Athena; Dirmeier, Reinhard; Gorman, Nadia; Sinclair, Peter R; Zhang, Li; Poyton, Robert O

    2003-12-12

    Heme plays central roles in oxygen sensing and utilization in many living organisms. In yeast, heme mediates the effect of oxygen on the expression of many genes involved in using or detoxifying oxygen. However, a direct link between intracellular heme level and oxygen concentration has not been vigorously established. In this report, we have examined the relationships among oxygen levels, heme levels, Hap1 activity, and HAP1 expression. We found that Hap1 activity is controlled in vivo by heme and not by its precursors and that heme activates Hap1 even in anoxic cells. We also found that Hap1 activity exhibits the same oxygen dose-response curves as Hap1-dependent aerobic genes and that these dose-response curves have a sharp break at approximately 1 microM O2. The results show that the intracellular signaling heme level, reflected as Hap1 activity, is closely correlated with oxygen concentration. Furthermore, we found that bypass of all heme synthetic steps but ferrochelatase by deuteroporphyrin IX does not circumvent the need for oxygen in Hap1 full activation by heme, suggesting that the last step of heme synthesis, catalyzed by ferrochelatase, is also subjected to oxygen control. Our results show that multiple heme synthetic steps can sense oxygen concentration and provide significant insights into the mechanism of oxygen sensing in yeast. PMID:14512429

  2. Two–Photon Oxygen Sensing with Quantum Dot–Porphyrin Conjugates

    PubMed Central

    Lemon, Christopher M.; Karnas, Elizabeth; Bawendi, Moungi G.; Nocera, Daniel G.

    2013-01-01

    Supramolecular assemblies of a quantum dot (QD) associated to palladium(II) porphyrins have been developed to detect oxygen (pO2) in organic solvents. Palladium porphyrins are sensitive in the 0–160 torr range, making them ideal phosphors for in vivo biological oxygen quantification. Porphyrins with meso pyridyl substituents bind to the surface of the QD to produce self–assembled nanosensors. Appreciable overlap between QD emission and porphyrin absorption features results in efficient Förster resonance energy transfer (FRET) for signal transduction in these sensors. The QD serves as a photon antenna, enhancing porphyrin emission under both one– and two–photon excitation, demonstrating that QD–palladium porphyrin conjugates may be used for oxygen sensing over physiological oxygen ranges. PMID:23978247

  3. Preparation, characterization and oxygen sensing properties of luminescent carbon dots assembled mesoporous silica microspheres.

    PubMed

    Wang, Li; Zhang, Haoran; Zhou, Xiaohua; Liu, Yingliang; Lei, Bingfu

    2016-09-15

    In this paper, our effort was focused on preparation and oxygen sensing of luminescence carbon dots (CDs) assembled hollow mesoporous silica microspheres (HMSMs) and mesoporous silica microspheres (MSMs). MSMs doped with CDs showed shorter response time and recovery time comparing with HMSMs doped with CDs. This feature can be attributed to ordered channel structure of mesoporous carrier which can promote the gas diffusion effectively. While HMSMs doped with CDs shows a higher oxygen quenching response and the degree of quenching reach 80.35%. The response time was determined to be about 7s and the emission intensities of the samples were effectively reduced as the concentration of oxygen increased. These results indicate that the system we have developed can be used for oxygen detection in wide concentration range and is especially accurate for very low oxygen concentrations. The obtained CDs grafted hollow mesoporous silica microspheres (HMSMs) and mesoporous silica microspheres (MSMs) samples appears to be a promising sensing material for environmental detection application and would also find applications in catalyst, electrode, or related fields. PMID:27309945

  4. Remote Sensing of Dissolved Oxygen and Nitrogen in Water using Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    De Young, R.; Ganoe, R.

    2013-12-01

    The health of an estuarine ecosystem is largely driven by the abundance of dissolved oxygen and nitrogen available for maintenance of plant and animal life. An investigation was conducted to quantify the concentration of dissolved molecular oxygen and nitrogen in water by means of Raman spectroscopy. This technique is proposed for the remote sensing of dissolved oxygen in the Chesapeake Bay, which will be utilized by aircraft in order to survey large areas in real-time. A proof of principle experiment has demonstrated the ability to remotely detect dissolved oxygen and nitrogen in pure water (also Chesapeake Bay water) using a 355nm Nd:YAG laser and a simple monochromater to detect the shifted Raman oxygen and nitrogen backscattered signals at 376.2 and 387.5 nm respectively. The theoretical basis for the research, components of the experimental system, and key findings are presented. A 1.3-m water cell had an attached vertical column to house a Troll 9500 dissolved oxygen in-situ monitor (In-Situ Inc Troll 9500). The Raman oxygen signal could be calibrated with this devise. While Raman backscattered water signals are low a potential aircraft remote system was designed and will be presented.

  5. Reversed oxygen sensing using colloidal quantum wells towards highly emissive photoresponsive varnishes.

    PubMed

    Lorenzon, Monica; Christodoulou, Sotirios; Vaccaro, Gianfranco; Pedrini, Jacopo; Meinardi, Francesco; Moreels, Iwan; Brovelli, Sergio

    2015-01-01

    Colloidal quantum wells combine the advantages of size-tunable electronic properties with vast reactive surfaces that could allow one to realize highly emissive luminescent-sensing varnishes capable of detecting chemical agents through their reversible emission response, with great potential impact on life sciences, environmental monitoring, defence and aerospace engineering. Here we combine spectroelectrochemical measurements and spectroscopic studies in a controlled atmosphere to demonstrate the 'reversed oxygen-sensing' capability of CdSe colloidal quantum wells, that is, the exposure to oxygen reversibly increases their luminescence efficiency. Spectroelectrochemical experiments allow us to directly relate the sensing response to the occupancy of surface states. Magneto-optical measurements demonstrate that, under vacuum, heterostructured CdSe/CdS colloidal quantum wells stabilize in their negative trion state. The high starting emission efficiency provides a possible means to enhance the oxygen sensitivity by partially de-passivating the particle surfaces, thereby enhancing the density of unsaturated sites with a minimal cost in term of luminescence losses. PMID:25910499

  6. High-flow nasal cannula oxygen therapy for acute exacerbation of interstitial pneumonia: A case series.

    PubMed

    Horio, Yukihiro; Takihara, Takahisa; Niimi, Kyoko; Komatsu, Masamichi; Sato, Masako; Tanaka, Jun; Takiguchi, Hiroto; Tomomatsu, Hiromi; Tomomatsu, Katsuyoshi; Hayama, Naoki; Oguma, Tsuyoshi; Aoki, Takuya; Urano, Tetsuya; Takagi, Atsushi; Asano, Koichiro

    2016-03-01

    We report 3 cases (all men, age: 69-81 years) of acute exacerbation of interstitial pneumonia (AEIP) that were successfully treated with a high-flow nasal cannula (HFNC), which delivers heated, humidified gas at a fraction of inspired oxygen (FIO2) up to 1.0 (100%). Oxygenation was insufficient under non-rebreathing face masks; however, the introduction of HFNC with an FIO2 of 0.7-1.0 (flow rate: 40L/min) improved oxygenation and was well-tolerated until the partial pressure of oxygen in blood/FIO2 ratio increased (between 21 and 26 days). Thus, HFNC might be an effective and well-tolerated therapeutic addition to the management of AEIP. PMID:26879483

  7. FIBER OPTICAL MICRO-DETECTORS FOR OXYGEN SENSING IN POWER PLANTS

    SciTech Connect

    Gregory L. Baker; Ruby N. Ghosh; D.J. Osborn III; Po Zhang

    2005-07-01

    A reflection mode fiber optic oxygen sensor is being developed that can operate at high temperatures for power plant applications. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. Two critical materials issues are the cluster's ability to withstand high temperatures when immobilized in a porous the sol-gel support, and whether after heating to high temperatures, the sol-gel matrix maintains a high and constant permeability to oxygen to support rapid quenching of luminescence. We used a composite materials approach to prepare stable sensing layers on optical fibers. We dispersed 60 w/w% of a pre-cured sol-gel composite containing the potassium salt of molybdenum clusters (K{sub 2}Mo{sub 6}Cl{sub 14}) into a sol-gel binder solution, and established the conditions necessary for deposition of sol-gel films on optical fibers and planar substrates. The fiber sensor has an output signal of 5 nW when pumped with an inexpensive commercial 365 nm ultraviolet light emitting diode (LED). Quenching of the sensor signal by oxygen was observed up to a gas temperature of 175 C with no degradation of the oxygen permeability of the composite after high temperature cycling. On planar substrates the cluster containing composite responds within <1 second to a gas exchange from nitrogen to oxygen, indicating the feasibility of real-time oxygen detection.

  8. A paradigm shift in oxygen sensing with a twist in the tale!

    PubMed

    O'Halloran, Ken D

    2016-09-01

    AMP-activated protein kinase (AMPK) is pivotal to metabolic homoeostasis in eukaryotes, serving as a critical energy sensor. Increased AMPK activity during oxygen deprivation (hypoxia) protects against potentially catastrophic deficits in ATP supply. Although the nervous system circuitry for elaboration of the complex cardiorespiratory response to hypoxia has been understood in some detail for many decades, there is continued and considerable interest in the molecular machinery underpinning the mechanism(s) of oxygen sensing. In this issue of the Biochemical Journal, Evans et al. [(2016) Biochem. J.] review their recent work, which points to a pivotal role for AMPK in the transduction of cellular hypoxic stress to integrated ventilatory behaviour, critical in the defence of whole-body oxygen homoeostasis. Of great surprise, there is profound blunting of the hyperventilatory response to hypoxic stress in AMPK deficient mice, with resultant dysregulated breathing arising in spite of normal peripheral oxygen sensing and appropriate sensory input to the brain! Their pointedly provocative review challenges current dogma, and in doing so raises intriguing questions that probe fundamental aspects of our understanding of the mammalian ventilatory response to hypoxic stress. The engaging review by Evans et al. [(2016) Biochem. J.] is an interesting read that is sure to encourage colourful debate. PMID:27574024

  9. Fabrication of Eu(III) complex doped nanofibrous membranes and their oxygen-sensing properties

    NASA Astrophysics Data System (ADS)

    Songzhu, Lin; Xiangting, Dong; Jinxian, Wang; Guixia, Liu; Wenshen, Yu; Ruokun, Jia

    2010-11-01

    In this paper, we report the synthesis, characterization, and photophysical properties of Eu(TTA) 3ECIP, where TTA = 2-thenoyltrifluoroacetonate, and ECIP = 1-ethyl-2-(N-ethyl-carbazole-yl-4-)imidazo[4,5-f]1,10-phenanthroline. Its elementary application for oxygen-sensing application is also investigated by doping it into a polymer matrix of polystyrene (PS). Experimental data suggest that the 2.5 wt% doped Eu(TTA) 3ECIP/PS nanofibrous membrane exhibits a high sensitivity of 3.4 towards oxygen with a good linear relationship of R2 = 0.9962. In addition, the 2.5 wt% doped Eu(TTA) 3ECIP/PS nanofibrous membrane owns a quick response of 8 s towards oxygen, along with its excellent atmosphere insensitivity and photobleaching resistance. All these results suggest that both Eu(TTA) 3ECIP and Eu(TTA) 3ECIP/PS system are promising candidates for oxygen-sensing optical sensors.

  10. Synthesis, characterization, photophysical and oxygen-sensing properties of a novel europium(III) complex

    NASA Astrophysics Data System (ADS)

    Feng, Nan; Xie, Jing; Zhang, Dawei

    2010-09-01

    In this paper, we report the synthesis, characterization, crystal structure, and photophysical properties of a novel Eu 3+ complex of Eu(DBM) 3IPD, where DBM = 1,3-diphenyl-propane-1,3-dione and IPD = 4-(1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl)-N,N-diphenylaniline. Its elementary application for oxygen-sensing application is also investigated by doping it into a silica matrix of MCM-41. Experimental data suggest that the 20 mg/g doped Eu(DBM) 3IPD/MCM-41 system exhibits a high sensitivity of 3.6 towards molecular oxygen with a good linear relationship of R2 = 0.9987. In addition, the 20 mg/g doped Eu(DBM) 3IPD/MCM-41 system owns a quick response of 8 s towards oxygen, along with its excellent atmosphere insensitivity and photobleaching resistance. All these results suggest that both Eu(DBM) 3IPD and Eu(DBM) 3IPD/MCM-41 systems are promising candidates for oxygen-sensing optical sensors.

  11. Facet effects of palladium nanocrystals for oxygen reduction in ionic liquids and for sensing applications

    NASA Astrophysics Data System (ADS)

    Tang, Yongan; Chi, Xiaowei; Zou, Shouzhong; Zeng, Xiangqun

    2016-03-01

    Palladium nanocrystals enclosed by {100} and {110} crystal facets, were successfully synthesized through an aqueous one-pot synthesis method. A new thermal annealing approach was developed for fabricating these palladium nanocrystals as a working electrode on a gas permeable membrane to study the facet effects of the oxygen reduction process in an ionic liquid, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([Bmpy][NTf2]). Results were compared with the same processes at a conventional platinum electrode. Our study shows that the structural difference between the two facets of Pd nanocrystals has little effect on the oxygen reduction process but significantly affects the oxidation process of the superoxide. It is found that the Pd{110}/IL interface can better stabilize superoxide radicals revealed by a more positive oxidation potential compared to that of Pd{100}. In addition, the analytical characteristic of utilizing both palladium nanocrystals as electrodes for oxygen sensing is comparable with a polycrystal platinum oxygen sensor, in which Pd{110} presents the best sensitivity and lowest detection limit. Our results demonstrate the facet-dependence of oxygen reduction in an ionic liquid medium and provide the fundamental information needed to guide the applications of palladium nanocrystals in electrochemical gas sensor and fuel cell research.Palladium nanocrystals enclosed by {100} and {110} crystal facets, were successfully synthesized through an aqueous one-pot synthesis method. A new thermal annealing approach was developed for fabricating these palladium nanocrystals as a working electrode on a gas permeable membrane to study the facet effects of the oxygen reduction process in an ionic liquid, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([Bmpy][NTf2]). Results were compared with the same processes at a conventional platinum electrode. Our study shows that the structural difference between the two facets of Pd

  12. Remote Sensing of Dissolved Oxygen and Nitrogen in Water Using Raman Spectroscopy

    NASA Technical Reports Server (NTRS)

    Ganoe, Rene; DeYoung, Russell J.

    2013-01-01

    The health of an estuarine ecosystem is largely driven by the abundance of dissolved oxygen and nitrogen available for maintenance of plant and animal life. An investigation was conducted to quantify the concentration of dissolved molecular oxygen and nitrogen in water by means of Raman spectroscopy. This technique is proposed for the remote sensing of dissolved oxygen in the Chesapeake Bay, which will be utilized by aircraft in order to survey large areas in real-time. A proof of principle system has been developed and the specifications are being honed to maximize efficiency for the final application. The theoretical criteria of the research, components of the experimental system, and key findings are presented in this report

  13. Acute transient non-physiological over-sensing in the ventricle with a DF4 lead

    PubMed Central

    Ng, Kevin Kit; Gould, Paul A.

    2015-01-01

    The DF-4 is a new defibrillator lead technology. We present two cases of non-physiological transient ventricular over-sensing in patients who underwent implantation of an ICD for secondary prevention. Case 1 had ventricular over-sensing during pacing threshold evaluation post defibrillation testing while Case 2 had the lead integrity alert triggered immediately post discharge with transient over-sensing. No lead-connector issues were found. Case 1 was likely due to improper venting of the header and trapped air. Case 2 was hypothesized to be due to intermittent header pin non-contact secondary to blood in the header. These cases reveal that DF-4 leads are subject to both reported and potentially novel causes of transient acute ventricular over-sensing. PMID:26937124

  14. Acute Variations in Retinal Vascular Oxygen Content in a Rabbit Model of Retinal Venous Occlusion

    PubMed Central

    Saati, Saloomeh; Martin, Gabriel; Chader, Gerald; Humayun, Mark S.

    2012-01-01

    Purpose To study the variation in intravascular oxygen saturation (oximetry) during an acute retinal vein occlusion (RVO) using hyperspectral computed tomographic spectroscopy based oximetry measurements. Methods Thirty rabbits were dilated and anesthetized for experiments. Baseline oximetry measurements were made using a custom-made hyperspectral computed tomographic imaging spectrometer coupled to a fundus camera. RVO were induced using argon green laser following an intravenous injection of Rose Bengal. RVO induction was confirmed by fluorescein angiography. Retinal oximetry measurements were repeated in arterial and venous branches one hour after RVO induction and up to 4 weeks afterwards. Comparison of retinal oximetry before and after vein occlusion was made using the Student T-test. Results One hour after RVO induction, we observed statistically significant reductions in the intravascular oxygen saturation in temporal retinal arteries (85.1±6.1% vs. 80.6±6.6%; p<0.0001) and veins (71.4±5.5% vs. 64.0±4.7%; p<0.0001). This decrease was reversible in animals that spontaneously recannulated the vein occlusion. There were no statistically significant differences in oxygen saturation in the nasal control arteries and veins before and after temporal vein RVO induction. Conclusions We demonstrate, for the first time, acute changes in the intravascular oxygen content of retinal vessels 1 hour after RVO. These changes are reversible upon spontaneous recannulation of retinal vessels. This study demonstrates that hyperspectral computer tomographic spectroscopy based oximetry can detect physiological variations in intravascular retinal oxygen saturation. The study also provides the first qualitative and quantitative evidence of the variation in retinal vascular oxygen content directly attributable to an acute retinal vein occlusion. PMID:23185567

  15. Thoracic Society of Australia and New Zealand oxygen guidelines for acute oxygen use in adults: ‘Swimming between the flags’*

    PubMed Central

    Beasley, Richard; Chien, Jimmy; Douglas, James; Eastlake, Leonie; Farah, Claude; King, Gregory; Moore, Rosemary; Pilcher, Janine; Richards, Michael; Smith, Sheree; Walters, Haydn

    2015-01-01

    The purpose of the Thoracic Society of Australia and New Zealand guidelines is to provide simple, practical evidence-based recommendations for the acute use of oxygen in adults in clinical practice. The intended users are all health professionals responsible for the administration and/or monitoring of oxygen therapy in the management of acute medical patients in the community and hospital settings (excluding perioperative and intensive care patients), those responsible for the training of such health professionals, and both public and private health care organizations that deliver oxygen therapy. PMID:26486092

  16. Regulation of carotid body oxygen sensing by hypoxia-inducible factors.

    PubMed

    Prabhakar, Nanduri R; Semenza, Gregg L

    2016-01-01

    Oxygen (O2) sensing by the carotid body and its chemosensory reflex is critical for homeostatic regulation of breathing and blood pressure. Carotid body responses to hypoxia are not uniform but instead exhibit remarkable inter-individual variations. The molecular mechanisms underlying variations in carotid body O2 sensing are not known. Hypoxia-inducible factor-1 (HIF-1) and HIF-2 mediate transcriptional responses to hypoxia. This article reviews the emerging evidence that proper expression of the HIF-α isoforms is a key molecular determinant for carotid body O2 sensing. HIF-1α deficiency leads to a blunted carotid body hypoxic response, which is due to increased abundance of HIF-2α, elevated anti-oxidant enzyme activity, and a reduced intracellular redox state. Conversely, HIF-2α deficiency results in augmented carotid body sensitivity to hypoxia, which is due to increased abundance of HIF-1α, elevated pro-oxidant enzyme activity, and an oxidized intracellular redox state. Double heterozygous mice with equally reduced HIF-1α and HIF-2α showed no abnormality in redox state or carotid body O2 sensing. Thus, mutual antagonism between HIF-α isoforms determines the redox state and thereby establishes the set point for hypoxic sensing by the carotid body. PMID:26265380

  17. Extracorporeal membrane oxygenation for the treatment of adult sickle cell acute chest syndrome.

    PubMed

    Parhar, Ken; Parizkova, Barbora; Jones, Nicola; Valchanov, Kamen; Fowles, Jo-Anne; Besser, Martin; Telfer, Paul; Kaya, Banu; Vuylsteke, Alain; Rubino, Antonio

    2016-04-01

    Sickle cell disease (SCD) is a hereditary haemoglobinopathy that results in polymerization of haemoglobin molecules and subsequent vaso-occlusion. A common cause of death in adults is acute chest syndrome (AChS) with resulting hypoxemic respiratory failure.Veno-venous extracorporeal membrane oxygenation (VV-ECMO) has been used successfully in acutely reversible respiratory failure when conventional mechanical ventilation has been unable to adequately oxygenate and ventilate in a lung-protective fashion.We present an adult SCD patient with severe respiratory failure due to AChS, successfully treated with VV-ECMO. We also discuss some of the technical challenges and considerations when using ECMO in the SCD patient. PMID:26130498

  18. A New Crosslinkable Oxygen Sensor Covalently Bonded into Poly(2-hydroxyethyl methacrylate)-CO-Polyacrylamide Thin Film for Dissolved Oxygen Sensing

    PubMed Central

    Tian, Yanqing; Shumway, Bradley R.; Meldrum, Deirdre R.

    2010-01-01

    A new oxygen sensor, compound 2, was synthesized through a chemical modification of a popularly used oxygen sensor of platinum(II)-5,10,15,20-tetrakis-(2,3,4,5,6-pentafluorophenyl)-porphyrin (PtTFPP). The new sensor compound 2 possesses four crosslinkable methacrylate functional moieties, enabling it to be polymerized and crosslinked with other monomers for polymer sensing film (also called membrane) preparation. Using this characteristic, compound 2 was covalently bonded to hydrophilic poly(2-hydroxyethyl methacrylate)-co-polyacrylamide (referred to as PHEMA to simplify) and hydrophobic polystyrene (PS) films. To better understand the advantages and disadvantages of chemical crosslinking approaches and the influence of polymer matrices on sensing performance, PtTFPP was physically incorporated into the same PHEMA and PS matrices to compare. Response to dissolved oxygen (DO), leaching of the sensor molecules from their matrices, photostability of the sensors, and response time to DO changes were studied. It was concluded that the chemical crosslinking of the sensor compound 2 in polymer matrices: (i) alleviated the leaching problem of sensor molecules which usually occurred in the physically doped sensing systems and (ii) significantly improved sensors’ photostability. The PHEMA matrix was demonstrated to be more suitable for oxygen sensing than PS, because for the same sensor molecule, the oxygen sensitivity in PHEMA film was higher than that in PS and response time to DO change in the PHEMA film was faster than that in PS. It was the first time oxygen sensing films were successfully prepared using biocompatible hydrophilic PHEMA as a matrix, which does not allow leaching of the sensor molecules from the polymer matrix, has a faster response to DO changes than that of PS, and does not present cytotoxicity to human lung adenocarcinoma epithelial cells (A549). It is expected that the new sensor compound 2 and its similar compounds with chemically crosslinking

  19. The human carotid body transcriptome with focus on oxygen sensing and inflammation – a comparative analysis

    PubMed Central

    Mkrtchian, Souren; Kåhlin, Jessica; Ebberyd, Anette; Gonzalez, Constancio; Sanchez, Diego; Balbir, Alexander; Kostuk, Eric W; Shirahata, Machiko; Fagerlund, Malin Jonsson; Eriksson, Lars I

    2012-01-01

    The carotid body (CB) is the key oxygen sensing organ. While the expression of CB specific genes is relatively well studied in animals, corresponding data for the human CB are missing. In this study we used five surgically removed human CBs to characterize the CB transcriptome with microarray and PCR analyses, and compared the results with mice data. In silico approaches demonstrated a unique gene expression profile of the human and mouse CB transcriptomes and an unexpected upregulation of both human and mouse CB genes involved in the inflammatory response compared to brain and adrenal gland data. Human CBs express most of the genes previously proposed to be involved in oxygen sensing and signalling based on animal studies, including NOX2, AMPK, CSE and oxygen sensitive K+ channels. In the TASK subfamily of K+ channels, TASK-1 is expressed in human CBs, while TASK-3 and TASK-5 are absent, although we demonstrated both TASK-1 and TASK-3 in one of the mouse reference strains. Maxi-K was expressed exclusively as the spliced variant ZERO in the human CB. In summary, the human CB transcriptome shares important features with the mouse CB, but also differs significantly in the expression of a number of CB chemosensory genes. This study provides key information for future functional investigations on the human carotid body. PMID:22615433

  20. Reversed oxygen sensing using colloidal quantum wells towards highly emissive photoresponsive varnishes

    NASA Astrophysics Data System (ADS)

    Lorenzon, Monica; Christodoulou, Sotirios; Vaccaro, Gianfranco; Pedrini, Jacopo; Meinardi, Francesco; Moreels, Iwan; Brovelli, Sergio

    2015-03-01

    Colloidal quantum wells combine the advantages of size-tunable electronic properties with vast reactive surfaces that could allow one to realize highly emissive luminescent-sensing varnishes capable of detecting chemical agents through their reversible emission response, with great potential impact on life sciences, environmental monitoring, defence and aerospace engineering. Here we combine spectroelectrochemical measurements and spectroscopic studies in a controlled atmosphere to demonstrate the ‘reversed oxygen-sensing’ capability of CdSe colloidal quantum wells, that is, the exposure to oxygen reversibly increases their luminescence efficiency. Spectroelectrochemical experiments allow us to directly relate the sensing response to the occupancy of surface states. Magneto-optical measurements demonstrate that, under vacuum, heterostructured CdSe/CdS colloidal quantum wells stabilize in their negative trion state. The high starting emission efficiency provides a possible means to enhance the oxygen sensitivity by partially de-passivating the particle surfaces, thereby enhancing the density of unsaturated sites with a minimal cost in term of luminescence losses.

  1. Reversed oxygen sensing using colloidal quantum wells towards highly emissive photoresponsive varnishes

    PubMed Central

    Lorenzon, Monica; Christodoulou, Sotirios; Vaccaro, Gianfranco; Pedrini, Jacopo; Meinardi, Francesco; Moreels, Iwan; Brovelli, Sergio

    2015-01-01

    Colloidal quantum wells combine the advantages of size-tunable electronic properties with vast reactive surfaces that could allow one to realize highly emissive luminescent-sensing varnishes capable of detecting chemical agents through their reversible emission response, with great potential impact on life sciences, environmental monitoring, defence and aerospace engineering. Here we combine spectroelectrochemical measurements and spectroscopic studies in a controlled atmosphere to demonstrate the ‘reversed oxygen-sensing’ capability of CdSe colloidal quantum wells, that is, the exposure to oxygen reversibly increases their luminescence efficiency. Spectroelectrochemical experiments allow us to directly relate the sensing response to the occupancy of surface states. Magneto-optical measurements demonstrate that, under vacuum, heterostructured CdSe/CdS colloidal quantum wells stabilize in their negative trion state. The high starting emission efficiency provides a possible means to enhance the oxygen sensitivity by partially de-passivating the particle surfaces, thereby enhancing the density of unsaturated sites with a minimal cost in term of luminescence losses. PMID:25910499

  2. Water-soluble phosphorescent ruthenium complex with a fluorescent coumarin unit for ratiometric sensing of oxygen levels in living cells.

    PubMed

    Hara, Daiki; Komatsu, Hirokazu; Son, Aoi; Nishimoto, Sei-Ichi; Tanabe, Kazuhito

    2015-04-15

    Dual emission was applied to a molecular probe for the ratiometric sensing of oxygen concentration in a living system. We prepared ruthenium complexes possessing a coumarin unit (Ru-Cou), in which the (3)MLCT phosphorescence of the ruthenium complex was efficiently quenched by molecular oxygen, whereas the coumarin unit emitted constant fluorescence independent of the oxygen concentration. The oxygen status could be determined precisely from the ratio of phosphorescence to fluorescence. We achieved the molecular imaging of cellular oxygen levels using Ru-Cou possessing an alkyl chain, which provided appropriate lipophilicity to increase cellular uptake. PMID:25848851

  3. Fiber-Based Laser Transmitter for Oxygen A-Band Spectroscopy and Remote Sensing

    NASA Technical Reports Server (NTRS)

    Stephen, Mark A.; Abshire, James B.

    2010-01-01

    A fiber-based laser transmitter has been designed for active remote-sensing spectroscopy. The transmitter uses a master-oscillator-power-amplifier (MOPA) configuration with a distributed feedback diode-laser master oscillator and an erbium-doped fiber amplifier. The output from the MOPA is frequency-doubled with a periodically poled nonlinear crystal. The utility of this single-frequency, wavelength-tunable, power-scalable laser has been demonstrated in a spectroscopic measurement of the diatomic oxygen A-band.

  4. Diversity of Magneto-Aerotactic Behaviors and Oxygen Sensing Mechanisms in Cultured Magnetotactic Bacteria

    PubMed Central

    Lefèvre, Christopher T.; Bennet, Mathieu; Landau, Livnat; Vach, Peter; Pignol, David; Bazylinski, Dennis A.; Frankel, Richard B.; Klumpp, Stefan; Faivre, Damien

    2014-01-01

    Microorganisms living in gradient environments affect large-scale processes, including the cycling of elements such as carbon, nitrogen or sulfur, the rates and fate of primary production, and the generation of climatically active gases. Aerotaxis is a common adaptation in organisms living in the oxygen gradients of stratified environments. Magnetotactic bacteria are such gradient-inhabiting organisms that have a specific type of aerotaxis that allows them to compete at the oxic-anoxic interface. They biomineralize magnetosomes, intracellular membrane-coated magnetic nanoparticles, that comprise a permanent magnetic dipole that causes the cells to align along magnetic field lines. The magnetic alignment enables them to efficiently migrate toward an optimal oxygen concentration in microaerobic niches. This phenomenon is known as magneto-aerotaxis. Magneto-aerotaxis has only been characterized in a limited number of available cultured strains. In this work, we characterize the magneto-aerotactic behavior of 12 magnetotactic bacteria with various morphologies, phylogenies, physiologies, and flagellar apparatus. We report six different magneto-aerotactic behaviors that can be described as a combination of three distinct mechanisms, including the reported (di-)polar, axial, and a previously undescribed mechanism we named unipolar. We implement a model suggesting that the three magneto-aerotactic mechanisms are related to distinct oxygen sensing mechanisms that regulate the direction of cells’ motility in an oxygen gradient. PMID:25028894

  5. Acute ethanol induces apoptosis by stimulating TRPC6 via elevation of superoxide in oxygenated podocytes.

    PubMed

    Lu, Xiao-Yu; Liu, Bing-Chen; Wang, Li-Hua; Yang, Li-Li; Bao, Qing; Zhai, Yu-Jia; Alli, Abdel A; Thai, Tiffany L; Eaton, Douglas C; Wang, Wei-Zhi; Ma, He-Ping

    2015-05-01

    Our recent studies indicate that hydrogen peroxide (H2O2) only at high concentrations can cause oxidative stress in renal epithelial cells and induce apoptosis of podocytes. Consistently, the present study shows that H2O2, even at 1 mM, failed to induce intracellular oxidative stress and apoptosis of the podocytes due to efficient activity of catalase, an enzyme which degrades H2O2 to produce water and oxygen (O2). However, H2O2 acted as a source of O2 to allow acute ethanol to induce superoxide production and cause apoptosis of the podocytes. In contrast, acute ethanol alone did not elevate intracellular superoxide, even though it stimulates expression and translocation of p47phox to the plasma membrane. Inhibition of catalase abolished not only O2 production from H2O2 degradation, but also NOX2-dependent superoxide production in the podocytes challenged by both H2O2 and acute ethanol. In parallel, acute ethanol in the presence of H2O2, but neither ethanol nor H2O2 alone, stimulated transient receptor potential canonical 6 (TRPC6) channels and caused TRPC6-dependent elevation of intracellular Ca2+. These data suggest that exogenous H2O2 does not induce oxidative stress due to rapid degradation to produce O2 in the podocytes, but the oxygenated podocytes become sensitive to acute ethanol challenge and undergo apoptosis via a TRPC6-dependent elevation of intracellular Ca2+. Since cultured podocytes are considered in hypoxic conditions, H2O2 may be used as a source of O2 to establish an ischemia-reperfusion model in some type of cultured cells in which H2O2 does not directly induce intracellular oxidative stress. PMID:25601712

  6. Oxygen sensing in neuroendocrine cells and other cell types: pheochromocytoma (PC12) cells as an experimental model.

    PubMed

    Spicer, Zachary; Millhorn, David E

    2003-01-01

    A steady supply of oxygen is an absolute requirement for mammalian cells to maintain normal cellular functions. To answer the challenge that oxygen deprivation represents, mammals have evolved specialized cell types that can sense changes in oxygen tension and alter gene expression to enhance oxygen delivery to hypoxic areas. These oxygensensing cells are rare and difficult to study in vivo. As a result, pheochromocytoma (PC12) cells have become a vital in vitro model system for deciphering the molecular events that confer the hypoxia-resistant and oxygen-sensing phenotypes. Research over the last few years has revealed that the hypoxia response in PC12 cells involves the interactions of several signal transduction pathways (Ca2+/calmodulin-dependent kinases, Akt, SAPKs, and MAPKs) and transcription factors (HIFs, CREB, and c-fos/junB). This review summarizes the current understanding of the role these signal transduction pathways and transcription factors play in determining the hypoxic response. PMID:14739486

  7. Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants

    SciTech Connect

    Gregory L. Baker; Ruby N. Ghosh; D. J. Osborn; Po Zhang

    2006-09-30

    A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications has been developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. We report on a fiber optic technique for detection of gas phase oxygen up to 100 C based on the {sup 3}O{sub 2} quenching of the luminescence from molybdenum chloride clusters, K{sub 2}Mo{sub 6}Cl{sub 14}. The inorganic sensing film is a composite of sol-gel particles embedded in a thin, oxygen permeable sol-gel binder. The particles are comprised of thermally stable, luminescent K{sub 2}Mo{sub 6}Cl{sub 14} clusters dispersed in a fully equilibrated sol-gel matrix. From 40 to 100 C, the fiber sensor switches {approx}6x in intensity in response to alternating pulses of <0.001% O2 and 21% O{sub 2} between two well defined levels with a response time of 10 s. The sensor signal is a few nW for an input pump power of 250 {micro}W. The normalized sensor signal is linear with molar oxygen concentration and fits the theoretical Stern-Volmer relationship. Although the sensitivity decreases with temperature, sensitivity at 100 C is 160 [O{sub 2}]{sup -1}. These parameters are well suited for in-situ, real-time monitoring of oxygen for industrial process control applications.

  8. Relationship between the microscopic and macroscopic world in optical oxygen sensing: a luminescence lifetime microscopy study.

    PubMed

    López-Gejo, Juan; Haigh, David; Orellana, Guillermo

    2010-02-01

    An investigation based on confocal fluorescence lifetime imaging microscopy (FLIM) of silica-loaded silicone films doped with a molecular oxygen-sensitive ruthenium(II) polyazaheterocyclic complex is presented. The effect of the silica type (hydrophilic/hydrophobic), particle size and amount of silica filler on the luminescence decay of the immobilized indicator dye has thoroughly been studied. A higher amount of hydrophilic silica leads to both a higher solubility of molecular oxygen into the silicone film and to higher levels of the metal indicator dye. Thus, incorporation of 10% (by wt) pyrogenic silica into silicone shortens the mean luminescence lifetime from 1.4 to 0.9 micros. However, an excess of filler may lead to overloading of the dye into the film producing new phenomena such as triplet-triplet annihilation and excitation energy homotransfer, as observed from their influence on the emission lifetime of the metal complex. Those phenomena do not take place when trimethylated silica (hydrophobic filler) is used. In this case, no increase on the oxygen or dye concentration is observed after addition of the filler and no significant reduction of the luminescence lifetime is measured. Both the addition of silica and the possible precipitation of dye crystals lead to the appearance of microdomains where the molecular probe exhibits widely different excited state lifetimes. For the first time, such microdomains within the oxygen sensing layer are visualized and analyzed by means of FLIM, showing the potential of this technique and the usefulness of our conclusions to the future design and development of novel luminescent oxygen sensor films for environmental and process analysis. PMID:20099927

  9. Enhanced gas sensing performance of Li-doped ZnO nanoparticle film by the synergistic effect of oxygen interstitials and oxygen vacancies

    NASA Astrophysics Data System (ADS)

    Zhao, Jianwei; Xie, Changsheng; Yang, Li; Zhang, Shunping; Zhang, Guozhu; Cai, Ziming

    2015-03-01

    Li doped ZnO (Zn1-xLixO) nanoparticles with different content were synthesized. X-ray photoelectron spectroscopy (XPS) indicated that the ratio of oxygen to zinc for ZnO increased with increasing of Li content from x = 0 to 0.2, which had been attributed to the introduction of oxygen interstitial by Li dopant. The sensing performance and the temperature-dependent conductivity were investigated. It is observed that Li doped ZnO showed higher sensitivity and selectivity compared to the undoped ZnO. The 0.1 Li doped ZnO performed the maximum responses of 71.5 and 40.2 for 100 ppm methanol and formaldehyde, respectively, at 350 °C. The research showed that the oxygen vacancies served as active sites which supported the oxygen adsorption and reaction, oxygen interstitials served as active sites to oxidize the reducing gases and produce electrons. The enhanced sensing performance of Li doped ZnO was attributed to the synergistic effect of oxygen interstitials and oxygen vacancies.

  10. Oxygen saturation changes in the optic nerve head during acute intraocular pressure elevation in monkeys

    NASA Astrophysics Data System (ADS)

    Khoobehi, Bahram; Kawano, Hiroyuki; Ning, Jinfeng; Burgoyne, Claude F.; Rice, David A.; Khan, Fareeha; Thompson, Hilary W.; Beach, James M.

    2009-02-01

    Background and Objective: To evaluate the effect of an acute elevated intraocular pressure (IOP) on oxygen saturation of structures of the optic nerve head. Study Design/Materials and Methods: In the cynomolgus monkey eye, IOP was set to 10 mm Hg, and then raised to 30, 45, and 55 mm Hg. The ONH and overlying vessels were imaged using a fundus camera attached to a hyperspectral imaging system (HSI) at 10 and 30 minutes after IOP elevation. Results: Raising IOP from 10 to 30 mm Hg did not significantly (P < 0.0001) change saturation in vessels or ONH tissue structures but at 55 mm Hg, all structures showed significant reduction. Conclusions: Quantitative assay of the blood oxygen saturation in structures on the surface and overlying the optic nerve head is possible using hyperspectral imaging techniques.

  11. Should hyperbaric oxygen be used to treat the pregnant patient for acute carbon monoxide poisoning

    SciTech Connect

    Van Hoesen, K.B.; Camporesi, E.M.; Moon, R.E.; Hage, M.L.; Piantadosi, C.A. )

    1989-02-17

    Carbon monoxide (CO) is the leading cause of death due to poisoning. Although uncommon, CO poisoning does occur during pregnancy and can result in fetal mortality and neurological malformations in fetuses who survive to term. Uncertainty arises regarding the use of hyperbaric oxygen (HBO) as a treatment for the pregnant patient because of possible adverse effects on the fetus that could be induced by oxygen at high partial pressures. While the dangers of hyperoxia to the fetus have been demonstrated in animal models, careful review of animal studies and human clinical experience indicates that the short duration of hyperoxic exposure attained during HBO therapy for CO poisoning can be tolerated by the fetus in all stages of pregnancy and reduces the risk of death or deformity to the mother and fetus. A case is presented of acute CO poisoning during pregnancy that was successfully treated with HBO. Recommendations are suggested for the use of HBO during pregnancy.

  12. Acute and chronic effects of atmospheric oxygen on the feeding behavior of Drosophila melanogaster larvae.

    PubMed

    Farzin, Manoush; Albert, Todd; Pierce, Nicholas; VandenBrooks, John M; Dodge, Tahnee; Harrison, Jon F

    2014-09-01

    All insects studied to date show reduced growth rates in hypoxia. Drosophila melanogaster reared in moderate hypoxia (10 kPa PO2) grow more slowly and form smaller adults, but the mechanisms responsible are unclear, as metabolic rates are not oxygen-limited. It has been shown that individual fruit flies do not grow larger in hyperoxia (40 kPa PO2), but populations of flies evolve larger size. Here we studied the effect of acute and chronic variation in atmospheric PO2 (10, 21, 40 kPa) on feeding behavior of third instar larvae of D.melanogaster to assess whether oxygen effects on growth rate can be explained by effects on feeding behavior. Hypoxic-reared larvae grew and developed more slowly, and hyperoxic-rearing did not affect growth rate, maximal larval mass or developmental time. The effect of acute exposure to varying PO2 on larval bite rates matched the pattern observed for growth rates, with a 22% reduction in 10 kPa PO2 and no effect of 40 kPa PO2. Chronic rearing in hypoxia had few effects on the responses of feeding rates to oxygen, but chronic rearing in hyperoxia caused feeding rates to be strongly oxygen-dependent. Hypoxia produced similar reductions in bite rate and in the volume of tunnels excavated by larvae, supporting bite rate as an index of feeding behavior. Overall, our data show that reductions in feeding rate can explain reduced growth rates in moderate hypoxia for Drosophila, contributing to reduced body size, and that larvae cannot successfully compensate for this level of hypoxia with developmental plasticity. PMID:25008193

  13. Effect of Acute Dietary Nitrate Consumption on Oxygen Consumption During Submaximal Exercise in Hypobaric Hypoxia.

    PubMed

    Carriker, Colin R; Mermier, Christine M; Van Dusseldorp, Trisha A; Johnson, Kelly E; Beltz, Nicholas M; Vaughan, Roger A; McCormick, James J; Cole, Nathan H; Witt, Christopher C; Gibson, Ann L

    2016-08-01

    Reduced partial pressure of oxygen impairs exercise performance at altitude. Acute nitrate supplementation, at sea level, may reduce oxygen cost during submaximal exercise in hypobaric hypoxia. Therefore, we investigated the metabolic response during exercise at altitude following acute nitrate consumption. Ten well-trained (61.0 ± 7.4 ml/kg/min) males (age 28 ± 7 yr) completed 3 experimental trials (T1, T2, T3). T1 included baseline demographics, a maximal aerobic capacity test (VO2max) and five submaximal intensity cycling determination bouts at an elevation of 1600 m. A 4-day dietary washout, minimizing consumption of nitrate-rich foods, preceded T2 and T3. In a randomized, double-blind, placebo-controlled, crossover fashion, subjects consumed either a nitrate-depleted beetroot juice (PL) or ~12.8 mmol nitrate rich (NR) beverage 2.5 hr before T2 and T3. Exercise at 3500 m (T2 and T3) via hypobaric hypoxia consisted of a 5-min warm-up (25% of normobaric VO2max) and four 5-min cycling bouts (40, 50, 60, 70% of normobaric VO2max) each separated by a 4-min rest period. Cycling RPM and watts for each submaximal bout during T2 and T3 were determined during T1. Preexercise plasma nitrite was elevated following NR consumption compared with PL (1.4 ± 1.2 and 0.7 ± 0.3 uM respectively; p < .05). There was no difference in oxygen consumption (-0.5 ± 1.8, 0.1 ± 1.7, 0.7 ± 2.1, and 1.0 ± 3.0 ml/kg/min) at any intensity (40, 50, 60, 70% of VO2max, respectively) between NR and PL. Further, respiratory exchange ratio, oxygen saturation, heart rate and rating of perceived exertion were not different at any submaximal intensity between NR and PL either. Blood lactate, however, was reduced following NR consumption compared with PL at 40 and 60% of VO2max (p < .0.05). Our findings suggest that acute nitrate supplementation before exercise at 3500 m does not reduce oxygen cost but may reduce blood lactate accumulation at lower intensity workloads. PMID:26630309

  14. Acute Supramaximal Exercise Increases the Brain Oxygenation in Relation to Cognitive Workload.

    PubMed

    Bediz, Cem Seref; Oniz, Adile; Guducu, Cagdas; Ural Demirci, Enise; Ogut, Hilmi; Gunay, Erkan; Cetinkaya, Caner; Ozgoren, Murat

    2016-01-01

    Single bout of exercise can improve the performance on cognitive tasks. However, cognitive responses may be controversial due to different type, intensity, and duration of exercise. In addition, the mechanism of the effect of acute exercise on brain is still unclear. This study was aimed to investigate the effects of supramaximal exercise on cognitive tasks by means of brain oxygenation monitoring. The brain oxygenation of Prefrontal cortex (PFC) was measured on 35 healthy male volunteers via functional near infrared spectroscopy (fNIRS) system. Subjects performed 2-Back test before and after the supramaximal exercise wingate anerobic test (WAnT) lasting 30-s on cycle ergometer. The PFC oxygenation change evaluation revealed that PFC oxygenation rise during post-exercise 2-Back task was considerably higher than those in pre-exercise 2-Back task. In order to describe the relationship between oxygenation change and exercise performance, subjects were divided into two groups as high performers (HP) and low performers (LP) according to their peak power values (PP) obtained from the supramaximal test. The oxy-hemoglobin (oxy-Hb) values were compared between pre- and post-exercise conditions within subjects and also between subjects according to peak power. When performers were compared, in the HP group, the oxy-Hb values in post-exercise 2-Back test were significantly higher than those in pre-exercise 2-Back test. HP had significantly higher post-exercise oxy-Hb change (Δ) than those of LP. In addition, PP of the total group were significantly correlated with Δoxy-Hb.The key findings of the present study revealed that acute supramaximal exercise has an impact on the brain oxygenation during a cognitive task. Also, the higher the anerobic PP describes the larger the oxy-Hb response in post-exercise cognitive task. The current study also demonstrated a significant correlation between peak power (exercise load) and post-exercise hemodynamic responses (oxy-, deoxy- and

  15. Ventilation-perfusion mismatching in acute severe asthma: effects of salbutamol and 100% oxygen.

    PubMed Central

    Ballester, E; Reyes, A; Roca, J; Guitart, R; Wagner, P D; Rodriguez-Roisin, R

    1989-01-01

    Ventilation-perfusion (VA/Q) relationships and gas exchange were studied by the multiple inert gas technique in 19 patients admitted to hospital with acute severe asthma (FEV1 41% predicted) before and during the administration of intravenous salbutamol, inhaled salbutamol, or 100% oxygen. Eight patients received a continuous intravenous infusion of salbutamol (4 micrograms/min, total dose 360 micrograms) and were studied before treatment, after 60 and 90 minutes of treatment, and one hour after treatment had been discontinued. Six patients had measurements before and 15 minutes after inhaling 300 micrograms salbutamol from a metered dose inhaler on two occasions (total dose 600 micrograms) and one hour after the last dose. Measurements were also made in five patients before and while they breathed 100% oxygen for 20 minutes. At baseline (fractional inspired oxygen (FiO2) 21%) all patients showed a broad unimodal (n = 10) or bimodal (n = 9) distribution of blood flow with respect to VA/Q. A mean of 10.5% of the blood flow was associated with low VA/Q units without any appreciable shunt. One of the best descriptors of VA/Q inequality, the second moment of the perfusion distribution on a log scale (log SD Q), was moderately high with a mean of 1.18 (SEM 0.08) (normal less than 0.6). Measures of VA/Q inequality correlated poorly with spirometric findings. After salbutamol the increase in airflow rates was similar regardless of the route of administration. Intravenous salbutamol, however, caused a significant increase in heart rate, cardiac output, and oxygen consumption (VO2); in addition, both perfusion to low VA/Q areas and log SD Q increased significantly. Inhaled salbutamol caused only minor changes in heart rate, cardiac output, VO2, and VA/Q inequality. Arterial oxygen tension (PaO2) remained unchanged during salbutamol administration, irrespective of the route of administration. During 100% oxygen breathing there was a significant increase in log SD Q (from 1

  16. Acute Supramaximal Exercise Increases the Brain Oxygenation in Relation to Cognitive Workload

    PubMed Central

    Bediz, Cem Seref; Oniz, Adile; Guducu, Cagdas; Ural Demirci, Enise; Ogut, Hilmi; Gunay, Erkan; Cetinkaya, Caner; Ozgoren, Murat

    2016-01-01

    Single bout of exercise can improve the performance on cognitive tasks. However, cognitive responses may be controversial due to different type, intensity, and duration of exercise. In addition, the mechanism of the effect of acute exercise on brain is still unclear. This study was aimed to investigate the effects of supramaximal exercise on cognitive tasks by means of brain oxygenation monitoring. The brain oxygenation of Prefrontal cortex (PFC) was measured on 35 healthy male volunteers via functional near infrared spectroscopy (fNIRS) system. Subjects performed 2-Back test before and after the supramaximal exercise wingate anerobic test (WAnT) lasting 30-s on cycle ergometer. The PFC oxygenation change evaluation revealed that PFC oxygenation rise during post-exercise 2-Back task was considerably higher than those in pre-exercise 2-Back task. In order to describe the relationship between oxygenation change and exercise performance, subjects were divided into two groups as high performers (HP) and low performers (LP) according to their peak power values (PP) obtained from the supramaximal test. The oxy-hemoglobin (oxy-Hb) values were compared between pre- and post-exercise conditions within subjects and also between subjects according to peak power. When performers were compared, in the HP group, the oxy-Hb values in post-exercise 2-Back test were significantly higher than those in pre-exercise 2-Back test. HP had significantly higher post-exercise oxy-Hb change (Δ) than those of LP. In addition, PP of the total group were significantly correlated with Δoxy-Hb.The key findings of the present study revealed that acute supramaximal exercise has an impact on the brain oxygenation during a cognitive task. Also, the higher the anerobic PP describes the larger the oxy-Hb response in post-exercise cognitive task. The current study also demonstrated a significant correlation between peak power (exercise load) and post-exercise hemodynamic responses (oxy-, deoxy- and

  17. Luminescent Nafion membranes dyed with ruthenium(II) complexes as sensing materials for dissolved oxygen

    SciTech Connect

    Garcia-Fresnadillo, D.; Orellana, G.; Marazuela, M.D.; Moreno-Bondi, M.C.

    1999-09-14

    The absorption spectroscopy, photophysics, and dioxygen quenching of [RuL{sub 3}]{sup 2+} luminescent probes, where L stands for 2,2{prime}-bipyridine, 1,10-phenanthroline, 5-octadecanamide-1,10-phenanthroline, and 4,7-diphenyl-1,10-phenanthroline (dip), electrostatically loaded onto Nafion ionomer membrane have been investigated in air and in organic solvents and water, with the aim of developing rugged materials for optical sensing of molecular oxygen. The significant differences in size and hydrophobicity of the Ru(II) dyes have been used to probe their location within the perfluorinated ionomer pore network, as well as to gain insight into the oxygen accessibility to its microcrystalline and interfacial domains. While the absorption maximums of the probes (444--458nm) remain relative unchanged, their emission wavelengths (578--622 nm) are extremely sensitive to the degree of Nafion swelling by the solvent. This feature has been characterized by measuring the density (1.19--2.04 g cm{sup {minus}3}) of the solvent-saturated ionomer and the mass and volume fractions of solvents (0.0--0.7) uptake by the original acidic Nafion and Li{sup +}-, Na{sup +}-, or K{sup +}-exchanged films. The excited-state lifetimes of the [RuL{sub 3}]{sup 2+} complexes (0.03--4.9{micro}s) reflect important variations of the microenvironment around the luminescent probes, which are rationalized in terms of their location and oxygen accessibility when loaded onto the polysulfonated material. Emission quenching rate constants of 1.7 {+-} 0.3 M{sup {minus}1}s{sup {minus}1} have been measured for the [Ru(dip){sub 3}]{sup 2+}-dyed films dipped in methanol; their oxygen sensitivity turns out to be independent of the Ru(II) loading and counterion of Nafion. Highly oxygen-sensitive luminescent membranes, suitable for continuous monitoring in organic solvents, water, or gas phase, have been prepared by immobilization of [Ru(dip){sub 3}]{sup 2+} indicator in 178-{micro}m thick Nafion, with response

  18. Room temperature alcohol sensing by oxygen vacancy controlled TiO2 nanotube array

    NASA Astrophysics Data System (ADS)

    Hazra, A.; Dutta, K.; Bhowmik, B.; Chattopadhyay, P. P.; Bhattacharyya, P.

    2014-08-01

    Oxygen vacancy (OV) controlled TiO2 nanotubes, having diameters of 50-70 nm and lengths of 200-250 nm, were synthesized by electrochemical anodization in the mixed electrolyte comprising NH4F and ethylene glycol with selective H2O content. The structural evolution of TiO2 nanoforms has been studied by field emission scanning electron microscopy. Variation in the formation of OVs with the variation of the structure of TiO2 nanoforms has been evaluated by photoluminescence and X-ray photoelectron spectroscopy. The sensor characteristics were correlated to the variation of the amount of induced OVs in the nanotubes. The efficient room temperature sensing achieved by the control of OVs of TiO2 nanotube array has paved the way for developing fast responding alcohol sensor with corresponding response magnitude of 60.2%, 45.3%, and 36.5% towards methanol, ethanol, and 2-propanol, respectively.

  19. Regional brain blood flow and cerebral hemispheric oxygen consumption during acute hypoxaemia in the llama fetus

    PubMed Central

    Llanos, Aníbal J; Riquelme, Raquel A; Sanhueza, Emilia M; Herrera, Emilio; Cabello, Gertrudis; Giussani, Dino A; Parer, Julian T

    2002-01-01

    Unlike fetal animals of lowland species, the llama fetus does not increase its cerebral blood flow during an episode of acute hypoxaemia. This study tested the hypothesis that the fetal llama brain maintains cerebral hemispheric O2 consumption by increasing cerebral O2 extraction rather than decreasing cerebral oxygen utilisation during acute hypoxaemia. Six llama fetuses were surgically instrumented under general anaesthesia at 217 days of gestation (term ca 350 days) with vascular and amniotic catheters in order to carry out cardiorespiratory studies. Following a control period of 1 h, the llama fetuses underwent 3 × 20 min episodes of progressive hypoxaemia, induced by maternal inhalational hypoxia. During basal conditions and during each of the 20 min of hypoxaemia, fetal cerebral blood flow was measured with radioactive microspheres, cerebral oxygen extraction was calculated, and fetal cerebral hemispheric O2 consumption was determined by the modified Fick principle. During hypoxaemia, fetal arterial O2 tension and fetal pH decreased progressively from 24 ± 1 to 20 ± 1 Torr and from 7.36 ± 0.01 to 7.33 ± 0.01, respectively, during the first 20 min episode, to 16 ± 1 Torr and 7.25 ± 0.05 during the second 20 min episode and to 14 ± 1 Torr and 7.21 ± 0.04 during the final 20 min episode. Fetal arterial partial pressure of CO2 (Pa,CO2, 42 ± 2 Torr) remained unaltered from baseline throughout the experiment. Fetal cerebral hemispheric blood flow and cerebral hemispheric oxygen extraction were unaltered from baseline during progressive hypoxaemia. In contrast, a progressive fall in fetal cerebral hemispheric oxygen consumption occurred during the hypoxaemic challenge. In conclusion, these data do not support the hypothesis that the fetal llama brain maintains cerebral hemispheric O2 consumption by increasing cerebral hemispheric O2 extraction. Rather, the data show that in the llama fetus, a reduction in cerebral hemispheric metabolism occurs during acute

  20. Effects of Repetitive Hyperbaric Oxygen Treatment in Patients with Acute Cerebral Infarction: A Pilot Study

    PubMed Central

    Chen, Cheng-Hsin; Chen, Shao-Yuan; Wang, Vinchi; Chen, Chao-Ching; Wang, Kaw-Chen; Chen, Chih-Hao; Liu, Yi-Chien; Lu, Kuo-Cheng; Yip, Ping-Keung; Ma, Wen-Ya; Liu, Chuan-Chieh

    2012-01-01

    The role of hyperbaric oxygen therapy (HBOT) in the treatment of acute ischemic stroke is controversial. This prospective study assessed the efficacy and safety of HBOT as adjuvant treatment on 46 acute ischemic stroke in patients who did not receive thrombolytic therapy. The HBOT group (n = 16) received conventional medical treatment with 10 sessions of adjunctive HBOT within 3–5 days after stroke onset, while the control group (n = 30) received the same treatment but without HBOT. Early (around two weeks after onset) and late (one month after onset) outcomes (National Institutes of Health Stroke Scale, NIHSS scores) and efficacy (changes of NIHSS scores) of HBOT were evaluated. The baseline clinical characteristics were similar in both groups. Both early and late outcomes of the HBOT group showed significant difference (P ≤ 0.001). In the control group, there was only significant difference in early outcome (P = 0.004). For early efficacy, there was no difference when comparing changes of NIHSS scores between the two groups (P = 0.140) but there was statistically significant difference when comparing changes of NIHSS scores at one month (P ≤ 0.001). The HBOT used in this study may be effective for patients with acute ischemic stroke and is a safe and harmless adjunctive treatment. PMID:22919348

  1. Acetazolamide during acute hypoxia improves tissue oxygenation in the human brain.

    PubMed

    Wang, Kang; Smith, Zachary M; Buxton, Richard B; Swenson, Erik R; Dubowitz, David J

    2015-12-15

    Low doses of the carbonic anhydrase inhibitor acetazolamide provides accelerated acclimatization to high-altitude hypoxia and prevention of cerebral and other symptoms of acute mountain sickness. We previously observed increases in cerebral O2 metabolism (CMRO2 ) during hypoxia. In this study, we investigate whether low-dose oral acetazolamide (250 mg) reduces this elevated CMRO2 and in turn might improve cerebral tissue oxygenation (PtiO2 ) during acute hypoxia. Six normal human subjects were exposed to 6 h of normobaric hypoxia with and without acetazolamide prophylaxis. We determined CMRO2 and cerebral PtiO2 from MRI measurements of cerebral blood flow (CBF) and cerebral venous O2 saturation. During normoxia, low-dose acetazolamide resulted in no significant change in CBF, CMRO2 , or PtiO2 . During hypoxia, we observed increases in CBF [48.5 (SD 12.4) (normoxia) to 65.5 (20.4) ml·100 ml(-1)·min(-1) (hypoxia), P < 0.05] and CMRO2 [1.54 (0.19) to 1.79 (0.25) μmol·ml(-1)·min(-1), P < 0.05] and a dramatic decline in PtiO2 [25.0 to 11.4 (2.7) mmHg, P < 0.05]. Acetazolamide prophylaxis mitigated these rises in CBF [53.7 (20.7) ml·100 ml(-1)·min(-1) (hypoxia + acetazolamide)] and CMRO2 [1.41 (0.09) μmol·ml(-1)·min(-1) (hypoxia + acetazolamide)] associated with acute hypoxia but also reduced O2 delivery [6.92 (1.45) (hypoxia) to 5.60 (1.14) mmol/min (hypoxia + acetazolamide), P < 0.05]. The net effect was improved cerebral tissue PtiO2 during acute hypoxia [11.4 (2.7) (hypoxia) to 16.5 (3.0) mmHg (hypoxia + acetazolamide), P < 0.05]. In addition to its renal effect, low-dose acetazolamide is effective at the capillary endothelium, and we hypothesize that local interruption in cerebral CO2 excretion accounts for the improvements in CMRO2 and ultimately in cerebral tissue oxygenation during hypoxia. This study suggests a potentially pivotal role of cerebral CO2 and pH in modulating CMRO2 and PtiO2 during acute hypoxia. PMID:26472861

  2. Human autonomic activity and its response to acute oxygen supplement after high altitude acclimatization.

    PubMed

    Bao, Xuping; Kennedy, Brian P; Hopkins, Susan R; Bogaard, Harm J; Wagner, Peter D; Ziegler, Michael G

    2002-11-29

    It is well established that after acclimatization at high altitude, many sympathetic pathways are hyperactive yet heart rate (HR) remains unchanged. In this study, we attempted to determine if this unchanged heart rate is due to compensatory mechanisms such as changes in parasympathetic activity or levels of receptors for autonomic neurotransmitters. We also examined the role played by hypoxia in these autonomic adaptations to high altitude. Three experiments were carried out on five healthy lowlanders both at sea level (SL) and after 2 weeks of acclimatization at 3800 m (Post-Ac) with: (a) placebo (control); (b) acute beta-adrenergic receptor blockade by propranolol (PRO), or (c) acute parasympathetic receptor blockade by glycopyrrolate (GLY). Compared with SL control values, post-Ac venous norepinephrine (NE) and dopamine increased by 96% (p < 0.001) and 55% (p < 0.05), but epinephrine and HR did not change. PRO resulted in a smaller decrease in HR (bpm) Post-Ac than at SL (15 +/- 6 vs. 21 +/- 6, p < 0.05), while GLY caused a greater increase in HR Post-Ac than at SL (59 +/- 8 vs. 45 +/- 6, p < 0.05). Breathing oxygen at SL concentration while at altitude did not decrease NE, or alter the effect of PRO on HR, but reduced the chronotropic effect of GLY by 14% (p < 0.05). These results suggest that after acclimatization to altitude, increased parasympathetic neurotransmitter release and decreased beta-adenoreceptor activity account for the unchanged HR despite enhanced sympathetic activity. Acute oxygen replacement rapidly counteracted the parasympathetic, but not sympathetic hyperactivity that occurs at high altitude. PMID:12492136

  3. Molybdenum chloride incorporated sol-gel materials for oxygen sensing above room temperature

    NASA Astrophysics Data System (ADS)

    Osborn, D. J., III

    Maximizing the efficiency of the combustion process requires the ability to sense oxygen levels over a broad range of concentrations with fast response times under rapidly varying conditions of pressure and temperature to maintain the correct fuel/oxygen ratio in real-time. Quenching of the luminescence from organometallic compounds by oxygen has been used to develop a number of fiber-based sensors. A major drawback of these organometallic indicators for combustion applications is that the chromophores degrade with time, have a limited operational temperature range, typically room temperature +/-25°C, and lack long-term reliability. This work investigates luminescent molybdenum clusters based on Mo6Cl12 were as replacements for organometallic indicators. A study of the high temperature stability of Mo6Cl 12 in air revealed irreversible changes in the optical absorption spectrum at T >250°C and a loss of the red luminescence characteristic of the pristine clusters. Thermal aging experiments run in air and under nitrogen point to oxidation of the clusters as the cause of the change in optical properties. X-ray powder diffraction measurements on samples annealed at 300°C under controlled conditions are consistent with oxidation of Mo6Cl 12 to form MoO3. Optical and thermal aging experiments show that K2Mo6Cl14•1H2O, the alkali metal salt of Mo6Cl12, has higher thermal stability and remains luminescent after long-term aging in air at 280°C. Methods were developed for depositing K2Mo6Cl14•1H 2O-incorporated sol--gel films on planar and optical fiber substrates by dip coating and spray coating. The mechanical properties of the films depended on the film thickness; thin films were stable, but cracks often formed in the thicker films needed for sensors. This problem was addressed using two strategies: altering the components of the sol--gel solutions used to embed the clusters and by devising a composite approach to sensing layers where a slurry of fully cured sol

  4. A green-emitting Cu complex for oxygen-sensing purpose: synthesis, characterization and photophysical features.

    PubMed

    Hui, Han; Wei, Li; Zhentao, Liu; Xiangen, Han

    2015-05-01

    In the present work, a green-emitting Cu(I) complex [Cu(BT-Et)(POP)]BF4 was synthesized and fully characterized, where BT-Et=4-(1-ethyl-1H-benzo[d]imidazol-2-yl)thiazole, POP=bis(2-(diphenylphosphanyl)phenyl) ether, respectively. An ethyl group was connected onto the diamine ligand to breach π-π attraction within solid [Cu(BT-Et)(POP)]BF4, favoring O2 molecule attack and sensitivity improvement. Its molecular identity was confirmed by single crystal analysis and theoretical calculation. [Cu(BT-Et)(POP)]BF4 emitted long-lived green emission peaking at 521nm upon photoexcitation which was vulnerable towards O2 molecule, making itself a potential oxygen sensing material. [Cu(BT-Et)(POP)]BF4 was then doped into a silica supporting matrix MCM-41. The resulting composite samples showed sensing behavior towards O2 molecule, with short response time of 10s and sensitivity of 5.56. PMID:25706596

  5. A green-emitting Cu complex for oxygen-sensing purpose: Synthesis, characterization and photophysical features

    NASA Astrophysics Data System (ADS)

    Hui, Han; Wei, Li; Zhentao, Liu; Xiangen, Han

    2015-05-01

    In the present work, a green-emitting Cu(I) complex [Cu(BT-Et)(POP)]BF4 was synthesized and fully characterized, where BT-Et = 4-(1-ethyl-1H-benzo[d]imidazol-2-yl)thiazole, POP = bis(2-(diphenylphosphanyl)phenyl) ether, respectively. An ethyl group was connected onto the diamine ligand to breach π-π attraction within solid [Cu(BT-Et)(POP)]BF4, favoring O2 molecule attack and sensitivity improvement. Its molecular identity was confirmed by single crystal analysis and theoretical calculation. [Cu(BT-Et)(POP)]BF4 emitted long-lived green emission peaking at 521 nm upon photoexcitation which was vulnerable towards O2 molecule, making itself a potential oxygen sensing material. [Cu(BT-Et)(POP)]BF4 was then doped into a silica supporting matrix MCM-41. The resulting composite samples showed sensing behavior towards O2 molecule, with short response time of 10 s and sensitivity of 5.56.

  6. Early non-destructive biofouling detection and spatial distribution: Application of oxygen sensing optodes.

    PubMed

    Farhat, N M; Staal, M; Siddiqui, A; Borisov, S M; Bucs, Sz S; Vrouwenvelder, J S

    2015-10-15

    Biofouling is a serious problem in reverse osmosis/nanofiltration (RO/NF) applications, reducing membrane performance. Early detection of biofouling plays an essential role in an adequate anti-biofouling strategy. Presently, fouling of membrane filtration systems is mainly determined by measuring changes in pressure drop, which is not exclusively linked to biofouling. Non-destructive imaging of oxygen concentrations (i) is specific for biological activity of biofilms and (ii) may enable earlier detection of biofilm accumulation than pressure drop. The objective of this study was to test whether transparent luminescent planar O2 optodes, in combination with a simple imaging system, can be used for early non-destructive biofouling detection. This biofouling detection is done by mapping the two-dimensional distribution of O2 concentrations and O2 decrease rates inside a membrane fouling simulator (MFS). Results show that at an early stage, biofouling development was detected by the oxygen sensing optodes while no significant increase in pressure drop was yet observed. Additionally, optodes could detect spatial heterogeneities in biofouling distribution at a micro scale. Biofilm development started mainly at the feed spacer crossings. The spatial and quantitative information on biological activity will lead to better understanding of the biofouling processes, contributing to the development of more effective biofouling control strategies. PMID:26117369

  7. A phosphorescent copper(I) complex: Synthesis, characterization, photophysical property, and oxygen-sensing behavior

    NASA Astrophysics Data System (ADS)

    Wen, Caihong; Tao, Guoquan; Xu, Xinhua; Feng, Xiaoqing; Luo, Rongcheng

    2011-09-01

    In this paper, we report the synthesis, crystal structure, photophysical properties, and electronic nature of a phosphorescent Cu(I) complex of [Cu(Phen-Np)(POP)]BF 4, where Phen-Np and POP stand for 2-(naphthalen-1-yl)-1H-imidazo[4,5-f][1,10]phenanthroline and bis(2-(diphenylphosphanyl)phenyl) ether, respectively. [Cu(Phen-Np)(POP)]BF 4 renders a yellow phosphorescence peaking at 545 nm, with a long excited state lifetime of 4.69 μs. Density functional calculation reveals that the emission comes from a triplet metal-to-ligand-charge-transfer excited state. We electrospun composite nanofibers of [Cu(Phen-Np)(POP)]BF 4 and polystyrene (PS), hoping to explore the possibility of using the composite nanofibers as an oxygen sensing material. The finally obtained samples with average diameter of ˜300 nm exhibit a maximum sensitivity of 7.2 towards molecular oxygen with short response time of 7 s due to the large surface-area-to-volume ratio of nanofibrous membranes. No photobleaching is detected in these samples.

  8. Synthesis, characterization and theoretical analysis on a oxygen-sensing phosphorescent copper(I) complex

    NASA Astrophysics Data System (ADS)

    Li, Zheng

    2011-10-01

    In this paper, we report the synthesis, crystal structure, photophysical properties, and electronic nature of a phosphorescent Cu(I) complex of [Cu(Phen-Ph)(PPh 3) 2]BF 4, where Phen-Ph and PPh 3 stand for 2-phenyl-1H-imidazo[4,5-f][1,10]phenanthroline and triphenylphosphine, respectively. [Cu(Phen-Ph)(PPh 3) 2]BF 4 renders a yellow phosphorescence peaking at 553 nm, with a long excited state lifetime of 13.2 μs under N 2 atmosphere. Density functional calculation reveals that the emission comes from a triplet metal-to-ligand-charge-transfer excited state. We electrospun composite nanofibers of [Cu(Phen-Ph)(PPh 3) 2]BF 4 and polystyrene (PS), hoping to explore the possibility of using the composite nanofibers as an oxygen sensing material. The finally obtained samples with average diameter of ˜400 nm exhibit a maximum sensitivity of 6.52 towards molecular oxygen with short response time of 15 s due to the large surface-area-to-volume ratio of nanofibrous membranes. No photobleaching is detected in these samples.

  9. Efficiency of hyperbaric oxygen therapy in experimental acute acoustic trauma from firearms.

    PubMed

    Kuokkanen, J; Aarnisalo, A A; Ylikoski, J

    2000-01-01

    In acute acoustic trauma (AAT), excessive noise exposure causes rupture of cell membranes and decreased cochlear blood flow. This leads to decreased oxygen tension in inner ear fluids and reduction of a variety of different oxygen-dependent cellular activities. Hyperbaric oxygen treatment (HBO) may help the cells suffering from hypoxia to survive. We exposed male Wistar rats to 60 impulses of 162-dB SPL from a 7.62-mm assault rifle equipped with a blank adaptor. After the exposure, 15 animals were given HBO treatment for 90 min daily for 10 consecutive days at 0.25 MPa. After a survival time of 4 weeks, auditory brainstem responses were measured and the left cochleae processed for light microscopy. The impulse noise caused permanent damage to the cochlea of all animals, with the most severe lesions in the lower middle coil, where a significantly smaller number of hair cells was missing in the HBO-treated group. The morphological damage was also reflected in function, as measured by auditory brainstem responses, which showed the greatest threshold shifts at 6.0, 8.0 and 10.0 kHz. PMID:10909001

  10. Oxygenation, EMG and position sense during computer mouse work. Impact of active versus passive pauses.

    PubMed

    Crenshaw, A G; Djupsjöbacka, M; Svedmark, A

    2006-05-01

    We investigated the effects of active versus passive pauses implemented during computer mouse work on muscle oxygenation and EMG of the forearm extensor carpi radialis muscle, and on wrist position sense. Fifteen healthy female subjects (age: 19-24 years) performed a 60-min mouse-operated computer task, divided into three 20 min periods, on two occasions separated by 3-6 days. On one occasion a passive pause (subjects resting) was implemented at the end of each 20-min period, and on another occasion an active pause (subjects performed a number of high intensity extensions of the forearm) was implemented. Also at the end of each 20-min period, test contractions were conducted and subjective ratings of fatigue and stress were obtained. Another parameter of interest was total haemoglobin calculated as the summation of oxy-and deoxy-haemoglobin, since it reflects blood volume changes. The most interesting findings were an overall increasing trend in total haemoglobin throughout the mouse work (P<0.001), and that this trend was greater for the active pause as compared to the passive pause (P<0.01). These data were accompanied by an overall increase in oxygen saturation (P<0.001), with a tendency, albeit not significant, toward a higher increase for the active pause (P=0.13). EMG amplitude and median frequency tended to decrease (P=0.08 and 0.05, respectively) during the mouse work but was not different between pause types. Borg ratings of forearm fatigue showed an overall increase during the activity (P<0.001), but the perceptions of stress did not change. Position sense did not change due to the mouse work for either pause type. While increasing trends were found for both pause types, the present study lends support to the hypothesis of an enhancement in oxygenation and blood volume for computer mouse work implemented with active pauses. However, a presumption of an association between this enhancement and attenuated fatigue during the mouse work was not supported

  11. Interdisciplinary Peripartum Management of Acute Respiratory Distress Syndrome with Extracorporeal Membrane Oxygenation – a Case Report and Literature Review

    PubMed Central

    Weyrich, J.; Bogdanski, R.; Ortiz, J. U.; Kuschel, B.; Schneider, K. T. M.; Lobmaier, S. M.

    2016-01-01

    Extracorporeal membrane oxygenation (ECMO) is increasingly used for the management of acute severe cardiac and respiratory failure. One of the indications is acute respiratory distress syndrome (ARDS) for which, in some severe cases, ECMO represents the only possibility to save lives. We report on the successful long-term use of ECMO in a postpartum patient with recurrent pulmonary decompensation after peripartum uterine rupture with extensive blood loss. PMID:27065489

  12. The role of oxygen in hydrogen sensing by a platinum-gate silicon carbide gas sensor: An ultrahigh vacuum study

    NASA Astrophysics Data System (ADS)

    Kahng, Yung Ho; Lu, Wei; Tobin, R. G.; Loloee, Reza; Ghosh, Ruby N.

    2009-03-01

    We report several experiments under ultrahigh vacuum conditions that elucidate the role of oxygen in the functioning of silicon carbide field-effect gas sensors with nonporous platinum gates. The devices studied are shown to be sensitive both to hydrogen and to propene. All of the results are consistent with oxygen acting through its surface reactions with hydrogen. Three specific aspects are highlighted: the need, under some conditions, for oxygen to reset the device to a fully hydrogen-depleted state; competition between hydrogen oxidation and hydrogen diffusion to metal/oxide interface sites, leading to steplike behavior as a function of the oxygen:hydrogen ratio (λ-sensing); and the removal of sulfur contamination by oxygen.

  13. Click-assembled, oxygen sensing nanoconjugates for depth-resolved, near-infrared imaging in a 3D cancer model

    PubMed Central

    Nichols, Alexander J.; Roussakis, Emmanuel; Klein, Oliver J.

    2014-01-01

    Hypoxia is an important factor that contributes to the development of drug-resistant cancer, yet few non-perturbative tools exist for studying oxygen in tissue. While progress has been made in the development of chemical probes for optical oxygen mapping, penetration into poorly perfused or avascular tumor regions remains problematic. Here we report a Click-Assembled Oxygen Sensing (CAOS) nanoconjugate and demonstrate its properties in an in vitro 3D spheroid cancer model. Our synthesis relies on sequential click-based ligation of poly(amidoamine)-like subunits for rapid assembly. Using near-infrared confocal phosphorescence microscopy, we demonstrate the ability of CAOS nanoconjugates to penetrate hundreds of microns into spheroids within hours and show their sensitivity to oxygen changes throughout the nodule. This proof-of-concept study demonstrates a modular approach that is readily extensible to a wide variety of oxygen and cellular sensors for depth-resolved imaging in tissue and tissue models. PMID:24590700

  14. High sensitivity and accuracy dissolved oxygen (DO) detection by using PtOEP/poly(MMA-co-TFEMA) sensing film.

    PubMed

    Zhang, Ke; Zhang, Honglin; Wang, Ying; Tian, Yanqing; Zhao, Jiupeng; Li, Yao

    2017-01-01

    Fluorinated acrylate polymer has received great interest in recent years due to its extraordinary characteristics such as high oxygen permeability, good stability, low surface energy and refractive index. In this work, platinum octaethylporphyrin/poly(methylmethacrylate-co-trifluoroethyl methacrylate) (PtOEP/poly(MMA-co-TFEMA)) oxygen sensing film was prepared by the immobilizing of PtOEP in a poly(MMA-co-TFEMA) matrix and the technological readiness of optical properties was established based on the principle of luminescence quenching. It was found that the oxygen-sensing performance could be improved by optimizing the monomer ratio (MMA/TFEMA=1:1), tributylphosphate(TBP, 0.05mL) and PtOEP (5μg) content. Under this condition, the maximum quenching ratio I0/I100 of the oxygen sensing film is obtained to be about 8.16, Stern-Volmer equation is I0/I=1.003+2.663[O2] (R(2)=0.999), exhibiting a linear relationship, good photo-stability, high sensitivity and accuracy. Finally, the synthesized PtOEP/poly(MMA-co-TFEMA) sensing film was used for DO detection in different water samples. PMID:27450122

  15. Microenvironmental oxygen partial pressure in acute myeloid leukemia: Is there really a role for hypoxia?

    PubMed

    Rieger, Christina T; Fiegl, Michael

    2016-07-01

    Reduced oxygen partial pressure (pO2) has been recognized as being relevant in hematopoiesis and the pathophysiology of malignant diseases. Although hypoxic (meaning insufficient supply of oxygen) and anoxic areas are present and of pathophysiologic importance (by hypoxia-induced pathways such as HiF1α) in solid tumors, this may not be true for (malignant) hematologic cells. Hematopoiesis occurs in the stem cell niche, which is characterized, among other things, by extremely low pO2. However, in contrast to solid tumors, in this context, the low pO2 is physiological and this feature, among others, is shared by the malignant stem cell niche harboring leukemia-initiating cells. Upon differentiation, hematopoietic cells are constantly exposed to changes in pO2 as they travel throughout the human body and encounter arterial and venous blood and migrate into oxygen-carrier-free tissue with low pO2. Hematologic malignancies such as acute myeloid leukemia (AML) make little difference in this respect and, whereas low oxygen is the usual environment of AML cells, recent evidence suggests no role for real hypoxia. Although there is no evidence that AML pathophysiology is related to hypoxia, leukemic blasts still show several distinct biological features when exposed to reduced pO2: they down- or upregulate membrane receptors such as CXCR4 or FLT3, activate or inhibit intracellular signaling pathways such as PI3K, and specifically secrete cytokines (IL-8). In summary, reduced pO2 should not be mistaken for hypoxia (nor should it be so called), and it does not automatically induce hypoxia-response mechanisms; therefore, a strict distinction should be made between physiologically low pO2 (physoxia) and hypoxia. PMID:27118044

  16. Luminescent sensing of dissolved oxygen based on Ru(II) complex embedded in sol-gel matrix

    NASA Astrophysics Data System (ADS)

    Bi, Yubing; Tao, Wei; Hu, Yanli; Mao, Yimei; Zhao, Hui

    2015-11-01

    In biological cells and tissues environment, real-time monitoring and controlling dissolved oxygen (DO) provides critical information for studying cellular metabolism process, health status and pathological features. This paper developed an optical DO sensor based on fluorescence quenching principle, prepared tris(4,7-diphenyl-1,10- phenanthroline)ruthenium(II) dichloride complex sol-gel sensing film, and studied its sensing performance. The principle of this sensor is that dissolved oxygen has quenching effect towards the fluorescence emitted by ruthenium complex. So the fluorescence intensity is reduced due to the existence of DO. The measurement limit of DO was 10- 100%, the response time was 20s, and the resolution was 0.02. Compared to traditional dissolved oxygen electrode probe, this luminescent fiber had many advantages, such as smaller size, shorter response time and higher stability.

  17. Combined administration of hyperbaric oxygen and hydroxocobalamin improves cerebral metabolism after acute cyanide poisoning in rats.

    PubMed

    Hansen, M B; Olsen, N V; Hyldegaard, O

    2013-11-01

    Hyperbaric oxygen therapy (HBOT) or intravenous hydroxocobalamin (OHCob) both abolish cyanide (CN)-induced surges in interstitial brain lactate and glucose concentrations. HBOT has been shown to induce a delayed increase in whole blood CN concentrations, whereas OHCob may act as an intravascular CN scavenger. Additionally, HBOT may prevent respiratory distress and restore blood pressure during CN intoxication, an effect not seen with OHCob administration. In this report, we evaluated the combined effects of HBOT and OHCob on interstitial lactate, glucose, and glycerol concentrations as well as lactate-to-pyruvate ratio in rat brain by means of microdialysis during acute CN poisoning. Anesthetized rats were allocated to three groups: 1) vehicle (1.2 ml isotonic NaCl intra-arterially); 2) potassium CN (5.4 mg/kg intra-arterially); 3) potassium CN, OHCob (100 mg/kg intra-arterially) and subsequent HBOT (284 kPa in 90 min). OHCob and HBOT significantly attenuated the acute surges in interstitial cerebral lactate, glucose, and glycerol concentrations compared with the intoxicated rats given no treatment. Furthermore, the combined treatment resulted in consistent low lactate, glucose, and glycerol concentrations, as well as in low lactate-to-pyruvate ratios compared with CN intoxicated controls. In rats receiving OHCob and HBOT, respiration improved and cyanosis disappeared, with subsequent stabilization of mean arterial blood pressure. The present findings indicate that a combined administration of OHCob and HBOT has a beneficial and persistent effect on the cerebral metabolism during CN intoxication. PMID:23970528

  18. Preservation of high glycolytic phenotype by establishing new acute lymphoblastic leukemia cell lines at physiologic oxygen concentration

    SciTech Connect

    Sheard, Michael A.; Ghent, Matthew V.; Cabral, Daniel J.; Lee, Joanne C.; Khankaldyyan, Vazgen; Ji, Lingyun; Wu, Samuel Q.; Kang, Min H.; and others

    2015-05-15

    Cancer cells typically exhibit increased glycolysis and decreased mitochondrial oxidative phosphorylation, and they continue to exhibit some elevation in glycolysis even under aerobic conditions. However, it is unclear whether cancer cell lines employ a high level of glycolysis comparable to that of the original cancers from which they were derived, even if their culture conditions are changed to physiologically relevant oxygen concentrations. From three childhood acute lymphoblastic leukemia (ALL) patients we established three new pairs of cell lines in both atmospheric (20%) and physiologic (bone marrow level, 5%) oxygen concentrations. Cell lines established in 20% oxygen exhibited lower proliferation, survival, expression of glycolysis genes, glucose consumption, and lactate production. Interestingly, the effects of oxygen concentration used during cell line initiation were only partially reversible when established cell cultures were switched from one oxygen concentration to another for eight weeks. These observations indicate that ALL cell lines established at atmospheric oxygen concentration can exhibit relatively low levels of glycolysis and these levels are semi-permanent, suggesting that physiologic oxygen concentrations may be needed from the time of cell line initiation to preserve the high level of glycolysis commonly exhibited by leukemias in vivo. - Highlights: • Establishing new ALL cell lines in 5% oxygen resulted in higher glycolytic expression and function. • Establishing new ALL cell lines in 5% oxygen resulted in higher proliferation and lower cell death. • The divergent metabolic phenotypes selected in 5% and 20% oxygen are semi-permanent.

  19. Acute exercise increases oxygenated and deoxygenated hemoglobin in the prefrontal cortex.

    PubMed

    Giles, Grace E; Brunyé, Tad T; Eddy, Marianna D; Mahoney, Caroline R; Gagnon, Stephanie A; Taylor, Holly A; Kanarek, Robin B

    2014-11-12

    Both acute and chronic exercise is consistently associated with a number of benefits to physical and mental health, including cardiovascular function, body weight, mood, and cognition. Near-infrared spectroscopy is an ideal method to measure changes in oxygenated and deoxygenated hemoglobin (O2Hb and dHb) levels in the prefrontal cortex (PFC) during exercise, to better understand the locus of such changes in affective and cognitive processes. The present study tracked time-dependent changes in O2Hb and dHb levels in the PFC as a function of parametrically manipulated target exercise intensity. Near-infrared spectroscopy was conducted as regular exercisers completed a 30-min bout of exercise with one of three target intensities: 52% (low condition), 68% (moderate condition), or 84% (high condition) of age-adjusted maximum heart rate. Heart rate data confirmed that the participants reached their goal intensities immediately, after 10 min, or after 20 min, respectively. Data showed that O2Hb and dHb levels in the PFC increased as a function of both exercise load and duration. An 84%>68%>52% difference was evident after 18 min of cycling for O2Hb and after 23 min of cycling for dHb. The present results add to the growing body of literature showing that at submaximal levels, increasing exercise intensities reliably promote prefrontal cerebral oxygenation. PMID:25275640

  20. Low Doses of Oxygen Ion Irradiation Cause Acute Damage to Hematopoietic Cells in Mice.

    PubMed

    Chang, Jianhui; Luo, Yi; Wang, Yingying; Pathak, Rupak; Sridharan, Vijayalakshmi; Jones, Tamako; Mao, Xiao Wen; Nelson, Gregory; Boerma, Marjan; Hauer-Jensen, Martin; Zhou, Daohong; Shao, Lijian

    2016-01-01

    One of the major health risks to astronauts is radiation on long-duration space missions. Space radiation from sun and galactic cosmic rays consists primarily of 85% protons, 14% helium nuclei and 1% high-energy high-charge (HZE) particles, such as oxygen (16O), carbon, silicon, and iron ions. HZE particles exhibit dense linear tracks of ionization associated with clustered DNA damage and often high relative biological effectiveness (RBE). Therefore, new knowledge of risks from HZE particle exposures must be obtained. In the present study, we investigated the acute effects of low doses of 16O irradiation on the hematopoietic system. Specifically, we exposed C57BL/6J mice to 0.1, 0.25 and 1.0 Gy whole body 16O (600 MeV/n) irradiation and examined the effects on peripheral blood (PB) cells, and bone marrow (BM) hematopoietic stem cells (HSCs) and hematopoietic progenitor cells (HPCs) at two weeks after the exposure. The results showed that the numbers of white blood cells, lymphocytes, monocytes, neutrophils and platelets were significantly decreased in PB after exposure to 1.0 Gy, but not to 0.1 or 0.25 Gy. However, both the frequency and number of HPCs and HSCs were reduced in a radiation dose-dependent manner in comparison to un-irradiated controls. Furthermore, HPCs and HSCs from irradiated mice exhibited a significant reduction in clonogenic function determined by the colony-forming and cobblestone area-forming cell assays. These acute adverse effects of 16O irradiation on HSCs coincided with an increased production of reactive oxygen species (ROS), enhanced cell cycle entry of quiescent HSCs, and increased DNA damage. However, none of the 16O exposures induced apoptosis in HSCs. These data suggest that exposure to low doses of 16O irradiation induces acute BM injury in a dose-dependent manner primarily via increasing ROS production, cell cycling, and DNA damage in HSCs. This finding may aid in developing novel strategies in the protection of the hematopoietic

  1. Low Doses of Oxygen Ion Irradiation Cause Acute Damage to Hematopoietic Cells in Mice

    PubMed Central

    Wang, Yingying; Pathak, Rupak; Sridharan, Vijayalakshmi; Jones, Tamako; Mao, Xiao Wen; Nelson, Gregory; Boerma, Marjan; Hauer-Jensen, Martin; Zhou, Daohong; Shao, Lijian

    2016-01-01

    One of the major health risks to astronauts is radiation on long-duration space missions. Space radiation from sun and galactic cosmic rays consists primarily of 85% protons, 14% helium nuclei and 1% high-energy high-charge (HZE) particles, such as oxygen (16O), carbon, silicon, and iron ions. HZE particles exhibit dense linear tracks of ionization associated with clustered DNA damage and often high relative biological effectiveness (RBE). Therefore, new knowledge of risks from HZE particle exposures must be obtained. In the present study, we investigated the acute effects of low doses of 16O irradiation on the hematopoietic system. Specifically, we exposed C57BL/6J mice to 0.1, 0.25 and 1.0 Gy whole body 16O (600 MeV/n) irradiation and examined the effects on peripheral blood (PB) cells, and bone marrow (BM) hematopoietic stem cells (HSCs) and hematopoietic progenitor cells (HPCs) at two weeks after the exposure. The results showed that the numbers of white blood cells, lymphocytes, monocytes, neutrophils and platelets were significantly decreased in PB after exposure to 1.0 Gy, but not to 0.1 or 0.25 Gy. However, both the frequency and number of HPCs and HSCs were reduced in a radiation dose-dependent manner in comparison to un-irradiated controls. Furthermore, HPCs and HSCs from irradiated mice exhibited a significant reduction in clonogenic function determined by the colony-forming and cobblestone area-forming cell assays. These acute adverse effects of 16O irradiation on HSCs coincided with an increased production of reactive oxygen species (ROS), enhanced cell cycle entry of quiescent HSCs, and increased DNA damage. However, none of the 16O exposures induced apoptosis in HSCs. These data suggest that exposure to low doses of 16O irradiation induces acute BM injury in a dose-dependent manner primarily via increasing ROS production, cell cycling, and DNA damage in HSCs. This finding may aid in developing novel strategies in the protection of the hematopoietic

  2. Roles of Proton-Sensing Receptors in the Transition from Acute to Chronic Pain.

    PubMed

    Sun, W H; Chen, C C

    2016-02-01

    Chronic pain, when not effectively treated, is a leading health and socioeconomic problem and has a harmful effect on all aspects of health-related quality of life. Therefore, understanding the molecular mechanism of how pain transitions from the acute to chronic phase is essential for developing effective novel analgesics. Accumulated evidence has shown that the transition from acute to chronic pain is determined by a cellular signaling switch called hyperalgesic priming, which occurs in primary nociceptive afferents. The hyperalgesic priming is triggered by inflammatory mediators and is involved in a signal switch from protein kinase A (PKA) to protein kinase Cε (PKCε) located in both isolectin B4 (IB4)-positive (nonpeptidergic) and IB4-negative (peptidergic) nociceptors. Acidosis may be the decisive factor regulating the PKA-to-PKCε signal switch in a proton-sensing G-protein-coupled receptor-dependent manner. Protons can also induce the hyperalgesic priming in IB4-negative muscle nociceptors in a PKCε-independent manner. Acid-sensing ion channel 3 (ASIC3) and transient receptor potential/vanilloid receptor subtype 1 (TRPV1) are 2 major acid sensors involved in the proton-induced hyperalgesic priming. The proton-induced hyperalgesic priming in muscle afferents can be prevented by a substance P-mediated signaling pathway. In this review, we summarize the factors that modulate hyperalgesic priming in both IB4-positive and IB4-negative nociceptors and discuss the role of acid signaling in inflammatory and noninflammatory pain as well as orofacial muscle pain. PMID:26597969

  3. Room temperature alcohol sensing by oxygen vacancy controlled TiO{sub 2} nanotube array

    SciTech Connect

    Hazra, A.; Dutta, K.; Bhowmik, B.; Bhattacharyya, P.; Chattopadhyay, P. P.

    2014-08-25

    Oxygen vacancy (OV) controlled TiO{sub 2} nanotubes, having diameters of 50–70 nm and lengths of 200–250 nm, were synthesized by electrochemical anodization in the mixed electrolyte comprising NH{sub 4}F and ethylene glycol with selective H{sub 2}O content. The structural evolution of TiO{sub 2} nanoforms has been studied by field emission scanning electron microscopy. Variation in the formation of OVs with the variation of the structure of TiO{sub 2} nanoforms has been evaluated by photoluminescence and X-ray photoelectron spectroscopy. The sensor characteristics were correlated to the variation of the amount of induced OVs in the nanotubes. The efficient room temperature sensing achieved by the control of OVs of TiO{sub 2} nanotube array has paved the way for developing fast responding alcohol sensor with corresponding response magnitude of 60.2%, 45.3%, and 36.5% towards methanol, ethanol, and 2-propanol, respectively.

  4. Cellular Oxygen Sensing: Crystal Structure of Hypoxia-Inducible Factor Prolyl Hydroxylase (PHD2)

    SciTech Connect

    McDonough,M.; Li, V.; Flashman, E.; Chowdhury, R.; Mohr, C.; Lienard, B.; Zondlo, J.; Oldham, N.; Clifton, I.; et al.

    2006-01-01

    Cellular and physiological responses to changes in dioxygen levels in metazoans are mediated via the posttranslational oxidation of hypoxia-inducible transcription factor (HIF). Hydroxylation of conserved prolyl residues in the HIF-{alpha} subunit, catalyzed by HIF prolyl-hydroxylases (PHDs), signals for its proteasomal degradation. The requirement of the PHDs for dioxygen links changes in dioxygen levels with the transcriptional regulation of the gene array that enables the cellular response to chronic hypoxia; the PHDs thus act as an oxygen-sensing component of the HIF system, and their inhibition mimics the hypoxic response. We describe crystal structures of the catalytic domain of human PHD2, an important prolyl-4-hydroxylase in the human hypoxic response in normal cells, in complex with Fe(II) and an inhibitor to 1.7 Angstroms resolution. PHD2 crystallizes as a homotrimer and contains a double-stranded {beta}-helix core fold common to the Fe(II) and 2-oxoglutarate-dependant dioxygenase family, the residues of which are well conserved in the three human PHD enzymes (PHD 1-3). The structure provides insights into the hypoxic response, helps to rationalize a clinically observed mutation leading to familial erythrocytosis, and will aid in the design of PHD selective inhibitors for the treatment of anemia and ischemic disease.

  5. Oxygen Sensing by T Cells Establishes an Immunologically Tolerant Metastatic Niche.

    PubMed

    Clever, David; Roychoudhuri, Rahul; Constantinides, Michael G; Askenase, Michael H; Sukumar, Madhusudhanan; Klebanoff, Christopher A; Eil, Robert L; Hickman, Heather D; Yu, Zhiya; Pan, Jenny H; Palmer, Douglas C; Phan, Anthony T; Goulding, John; Gattinoni, Luca; Goldrath, Ananda W; Belkaid, Yasmine; Restifo, Nicholas P

    2016-08-25

    Cancer cells must evade immune responses at distant sites to establish metastases. The lung is a frequent site for metastasis. We hypothesized that lung-specific immunoregulatory mechanisms create an immunologically permissive environment for tumor colonization. We found that T-cell-intrinsic expression of the oxygen-sensing prolyl-hydroxylase (PHD) proteins is required to maintain local tolerance against innocuous antigens in the lung but powerfully licenses colonization by circulating tumor cells. PHD proteins limit pulmonary type helper (Th)-1 responses, promote CD4(+)-regulatory T (Treg) cell induction, and restrain CD8(+) T cell effector function. Tumor colonization is accompanied by PHD-protein-dependent induction of pulmonary Treg cells and suppression of IFN-γ-dependent tumor clearance. T-cell-intrinsic deletion or pharmacological inhibition of PHD proteins limits tumor colonization of the lung and improves the efficacy of adoptive cell transfer immunotherapy. Collectively, PHD proteins function in T cells to coordinate distinct immunoregulatory programs within the lung that are permissive to cancer metastasis. PAPERCLIP. PMID:27565342

  6. Quantum Dots in an Amphiphilic Polyethyleneimine Derivative Platform for Cellular Labeling, Targeting, Gene Delivery, and Ratiometric Oxygen Sensing.

    PubMed

    Park, Joonhyuck; Lee, Junhwa; Kwag, Jungheon; Baek, Yeonggyeong; Kim, Bumju; Yoon, Calvin Jinse; Bok, Seoyeon; Cho, So-Hye; Kim, Ki Hean; Ahn, G-One; Kim, Sungjee

    2015-06-23

    Amphiphilic polyethyleneimine derivatives (amPEIs) were synthesized and used to encapsulate dozens of quantum dots (QDs). The QD-amPEI composite was ∼100 nm in hydrodynamic diameter and had the slightly positive outer surface that suited well for cellular internalization. The QD-amPEI showed very efficient QD cellular labeling with the labeled cell fluorescence intensity more than 10 times higher than conventional techniques such as Lipofectamine-assisted QD delivery. QD-amPEI was optimal for maximal intracellular QD delivery by the large QD payload and the rapid endocytosis kinetics. QD-amPEI platform technology was demonstrated for gene delivery, cell-specific labeling, and ratiometric oxygen sensing. Our QD-amPEI platform has two partitions: positive outer surface and hydrophobic inside pocket. The outer positive surface was further exploited for gene delivery and targeting. Co-delivery of QDs and GFP silencing RNAs was successfully demonstrated by assembling siRNAs to the outer surfaces, which showed the transfection efficiency an order of magnitude higher than conventional gene transfections. Hyaluronic acids were tethered onto the QD-amPEI for cell-specific targeted labeling which showed the specific-to-nonspecific signal ratio over 100. The inside hydrophobic compartment was further applied for cohosting oxygen sensing phosphorescence Ru dyes along with QDs. The QD-Ru-amPEI oxygen probe showed accurate and reversible oxygen sensing capability by the ratiometric photoluminescence signals, which was successfully applied to cellular and spheroid models. PMID:26057729

  7. Oxygen-sensing mechanisms and the regulation of redox-responsive transcription factors in development and pathophysiology

    PubMed Central

    Haddad, John J

    2002-01-01

    How do organisms sense the amount of oxygen in the environment and respond appropriately when the level of oxygen decreases? Oxygen sensing and the molecular stratagems underlying the process have been the focus of an endless number of investigations trying to find an answer to the question: "What is the identity of the oxygen sensor?" Dynamic changes in pO2 constitute a potential signaling mechanism for the regulation of the expression and activation of reduction-oxidation (redox)-sensitive and oxygen-responsive transcription factors, apoptosis-signaling molecules and inflammatory cytokines. The transition from placental to lung-based respiration causes a relatively hyperoxic shift or oxidative stress, which the perinatal, developing lung experiences during birth. This variation in ΔpO2, in particular, differentially regulates the compartmentalization and functioning of the transcription factors hypoxia-inducible factor-1α (HIF-1α) and nuclear factor-κB (NF-κB). In addition, oxygen-evoked regulation of HIF-1α and NF-κB is closely coupled with the intracellular redox state, such that modulating redox equilibrium affects their responsiveness at the molecular level (expression/transactivation). The differential regulation of HIF-1α and NF-κB in vitro is paralleled by oxygen-sensitive and redox-dependent pathways governing the regulation of these factors during the transition from placental to lung-based respiration ex utero. The birth transition period in vivo and ex utero also regulates apoptosis signaling pathways in a redox-dependent manner, consistent with NF-κB being transcriptionally regulated in order to play an anti-apoptotic function. An association is established between oxidative stress conditions and the augmentation of an inflammatory state in pathophysiology, regulated by the oxygen- and redox-sensitive pleiotropic cytokines. PMID:12537605

  8. Determination of the Role of Oxygen in Suspected Acute Myocardial Infarction by Biomarkers

    ClinicalTrials.gov

    2016-01-25

    Acute Myocardial Infarction (AMI); Acute Coronary Syndrome (ACS); ST Elevation (STEMI) Myocardial Infarction; Ischemic Reperfusion Injury; Non-ST Elevation (NSTEMI) Myocardial Infarction; Angina, Unstable

  9. Oxygen-Sensing Reporter Strain of Pseudomonas fluorescens for Monitoring the Distribution of Low-Oxygen Habitats in Soil

    PubMed Central

    Højberg, Ole; Schnider, Ursula; Winteler, Harald V.; Sørensen, Jan; Haas, Dieter

    1999-01-01

    The root-colonizing bacterium Pseudomonas fluorescens CHA0 was used to construct an oxygen-responsive biosensor. An anaerobically inducible promoter of Pseudomonas aeruginosa, which depends on the FNR (fumarate and nitrate reductase regulation)-like transcriptional regulator ANR (anaerobic regulation of arginine deiminase and nitrate reductase pathways), was fused to the structural lacZ gene of Escherichia coli. By inserting the reporter fusion into the chromosomal attTn7 site of P. fluorescens CHA0 by using a mini-Tn7 transposon, the reporter strain, CHA900, was obtained. Grown in glutamate-yeast extract medium in an oxystat at defined oxygen levels, the biosensor CHA900 responded to a decrease in oxygen concentration from 210 × 102 Pa to 2 × 102 Pa of O2 by a nearly 100-fold increase in β-galactosidase activity. Half-maximal induction of the reporter occurred at about 5 × 102 Pa. This dose response closely resembles that found for E. coli promoters which are activated by the FNR protein. In a carbon-free buffer or in bulk soil, the biosensor CHA900 still responded to a decrease in oxygen concentration, although here induction was about 10 times lower and the low oxygen response was gradually lost within 3 days. Introduced into a barley-soil microcosm, the biosensor could report decreasing oxygen concentrations in the rhizosphere for a 6-day period. When the water content in the microcosm was raised from 60% to 85% of field capacity, expression of the reporter gene was elevated about twofold above a basal level after 2 days of incubation, suggesting that a water content of 85% caused mild anoxia. Increased compaction of the soil was shown to have a faster and more dramatic effect on the expression of the oxygen reporter than soil water content alone, indicating that factors other than the water-filled pore space influenced the oxygen status of the soil. These experiments illustrate the utility of the biosensor for detecting low oxygen concentrations in the

  10. UHV Studies of Oxygen's Role in Hydrogen Sensing with a Platinum-Gate Silicon Carbide Field-Effect Device

    NASA Astrophysics Data System (ADS)

    Tobin, Roger; Kahng, Yung Ho; Loloee, Reza; Ghosh, Ruby

    2008-03-01

    Silicon carbide-based field-effect devices with catalytic metal gates are promising as robust high-temperature gas sensors in harsh environments. We report ultrahigh vacuum studies of the gate surface chemistry of prototype Pt-SiO2-SiC sensors. Oxygen plays a crucial role in the device's hydrogen-sensing behavior. Adsorbed oxygen can remove hydrogen by reacting to form water, which rapidly desorbs. In an oxygen-rich environment this reaction competes with the diffusion of adsorbed hydrogen to the interface bonding sites that give rise to the sensor signal. This competition reduces the sensor signal by decreasing the occupation of interface sites. The same reaction, however, is essential to the reversibility of the sensor, as oxygen is needed to fully deplete the sensor of hydrogen. Exposure to H2S suppresses the sensor's response to alternating hydrogen and oxygen pulses, apparently by interfering with oxygen adsorption. Continued oxygen exposure, however, restores functionality by effectively removing the sulfur.

  11. A power law fit to oxygen absorption at 60 GHz and its application to remote sensing of atmospheric temperature

    NASA Technical Reports Server (NTRS)

    Poon, R. K. L.

    1980-01-01

    The paper presents an empirical study of the oxygen spectrum near 60 GHz with reference to its applicability to the remote sensing of the tropospheric and lower stratospheric temperature. It is demonstrated that the absorption coefficient of oxygen at 60 GHz can be fitted to the power law form with a relative rms error of about 8%. The power law form, when used in conjunction with the weighting function, permits the definition of some basic quantities in the passive remote sensing of the atmospheric temperature. It is shown how the power law form has been utilized in processing data from the Nimbus 5 microwave spectrometer experiment. The algorithm presented can be applied to spectrometer experiments at infrared frequencies.

  12. Effects of nebulized terbutaline on oxygen saturation in acute asthmatic children.

    PubMed

    Lin, Y Z; Hsieh, K H; Shih, T Y; Chen, W; Wu, K W

    1994-01-01

    To evaluate the paradoxical effect of oxygen desaturation following beta-2 bronchodilator nebulization treatment in acute asthmatic children, a total of 47 patients, aged between 1.8 and 14 years, 27 males and 20 females, were studied. Twenty ml of nebulized normal saline (NS), followed by 10 mg (4 ml) of terbutaline sulphate solution (TSS) in 20 ml NS, were delivered by an ultrasonic nebulizer in 10 min to each patient through a connecting air tube placed in front of the nose and mouth. Oxygen saturation (SaO2) and pulse rate were monitored, using a pulse oximeter, before study and every two minutes until the end of the study. The clinical severity score and peak expiratory flow rate (PEFR) were checked before the study, at the end of inhalation of NS, and at the end of inhalation of TSS. SaO2 was increased both after nebulized NS and TSS when compared with the pre-study data (p < 0.05 and p < 0.0001, respectively). Twenty two cases (47%) during NS and 12 cases (25%) during TSS nebulization had SaO2 below the pre-study level. The mean decrease of SaO2 for the former was 1.62 +/- 0.95% (range: 1.00% to 4.26%), and 1.64 +/- 0.83% (range: 1.02% to 3.13%) for the latter (p > 0.9). No SaO2 decrease after nebulized TSS was observed in any of the seven severe asthmatic children with a prestudy SaO2 < or = 90%. The clinical severity score and PEFR were also significantly improved both after nebulized NS and TSS (p < 0.0001 and p < 0.001, respectively for NS, and both p < 0.0001 for TSS).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7942023

  13. F-box and Leucine-rich Repeat Protein 5 (FBXL5): sensing intracellular iron and oxygen

    PubMed Central

    Ruiz, Julio C.; Bruick, Richard K.

    2014-01-01

    Though essential for many vital biological processes, excess iron results in the formation of damaging reactive oxygen species (ROS). Therefore, iron metabolism must be tightly regulated. F-box and leucine-rich repeat protein 5 (FBXL5), an E3 ubiquitin ligase subunit, regulates cellular and systemic iron homeostasis by facilitating iron regulatory protein 2 (IRP2) degradation. FBXL5 possesses an N-terminal hemerythrin (Hr)-like domain that mediates its own differential stability by switching between two different conformations to communicate cellular iron availability. In addition, the FBXL5-Hr domain also senses O2 availability, albeit by a distinct mechanism. Mice lacking FBXL5 fail to sense intracellular iron levels and die in utero due to iron overload and exposure to damaging levels of oxidative stress. By closely monitoring intracellular levels of iron and oxygen, FBLX5 prevents the formation of conditions that favor ROS formation. These findings suggest that FBXL5 is essential for the maintenance of iron homeostasis and is a key sensor of bioavailable iron. Here, we describe the iron and oxygen sensing mechanisms of the FBXL5 Hr-like domain and its role in mediating ROS biology. PMID:24508277

  14. F-box and leucine-rich repeat protein 5 (FBXL5): sensing intracellular iron and oxygen.

    PubMed

    Ruiz, Julio C; Bruick, Richard K

    2014-04-01

    Though essential for many vital biological processes, excess iron results in the formation of damaging reactive oxygen species (ROS). Therefore, iron metabolism must be tightly regulated. F-box and leucine-rich repeat protein 5 (FBXL5), an E3 ubiquitin ligase subunit, regulates cellular and systemic iron homeostasis by facilitating iron regulatory protein 2 (IRP2) degradation. FBXL5 possesses an N-terminal hemerythrin (Hr)-like domain that mediates its own differential stability by switching between two different conformations to communicate cellular iron availability. In addition, the FBXL5-Hr domain also senses O2 availability, albeit by a distinct mechanism. Mice lacking FBXL5 fail to sense intracellular iron levels and die in utero due to iron overload and exposure to damaging levels of oxidative stress. By closely monitoring intracellular levels of iron and oxygen, FBLX5 prevents the formation of conditions that favor ROS formation. These findings suggest that FBXL5 is essential for the maintenance of iron homeostasis and is a key sensor of bioavailable iron. Here, we describe the iron and oxygen sensing mechanisms of the FBXL5 Hr-like domain and its role in mediating ROS biology. PMID:24508277

  15. The Complex Relationship of Extracorporeal Membrane Oxygenation and Acute Kidney Injury: Causation or Association?

    PubMed Central

    Kilburn, Daniel J.; Shekar, Kiran; Fraser, John F.

    2016-01-01

    Extracorporeal membrane oxygenation (ECMO) is a modified cardiopulmonary bypass (CPB) circuit capable of providing prolonged cardiorespiratory support. Recent advancement in ECMO technology has resulted in increased utilisation and clinical application. It can be used as a bridge-to-recovery, bridge-to-bridge, bridge-to-transplant, or bridge-to-decision. ECMO can restitute physiology in critically ill patients, which may minimise the risk of progressive multiorgan dysfunction. Alternatively, iatrogenic complications of ECMO clearly contribute to worse outcomes. These factors affect the risk : benefit ratio of ECMO which ultimately influence commencement/timing of ECMO. The complex interplay of pre-ECMO, ECMO, and post-ECMO pathophysiological processes are responsible for the substantial increased incidence of ECMO-associated acute kidney injury (EAKI). The development of EAKI significantly contributes to morbidity and mortality; however, there is a lack of evidence defining a potential benefit or causative link between ECMO and AKI. This area warrants investigation as further research will delineate the mechanisms involved and subsequent strategies to minimise the risk of EAKI. This review summarizes the current literature of ECMO and AKI, considers the possible benefits and risks of ECMO on renal function, outlines the related pathophysiology, highlights relevant investigative tools, and ultimately suggests an approach for future research into this under investigated area of critical care. PMID:27006941

  16. Acute health impacts of airborne particles estimated from satellite remote sensing.

    PubMed

    Wang, Zhaoxi; Liu, Yang; Hu, Mu; Pan, Xiaochuan; Shi, Jing; Chen, Feng; He, Kebin; Koutrakis, Petros; Christiani, David C

    2013-01-01

    Satellite-based remote sensing provides a unique opportunity to monitor air quality from space at global, continental, national and regional scales. Most current research focused on developing empirical models using ground measurements of the ambient particulate. However, the application of satellite-based exposure assessment in environmental health is still limited, especially for acute effects, because the development of satellite PM(2.5) model depends on the availability of ground measurements. We tested the hypothesis that MODIS AOD (aerosol optical depth) exposure estimates, obtained from NASA satellites, are directly associated with daily health outcomes. Three independent healthcare databases were used: unscheduled outpatient visits, hospital admissions, and mortality collected in Beijing metropolitan area, China during 2006. We use generalized linear models to compare the short-term effects of air pollution assessed by ground monitoring (PM(10)) with adjustment of absolute humidity (AH) and AH-calibrated AOD. Across all databases we found that both AH-calibrated AOD and PM(10) (adjusted by AH) were consistently associated with elevated daily events on the current day and/or lag days for cardiovascular diseases, ischemic heart diseases, and COPD. The relative risks estimated by AH-calibrated AOD and PM(10) (adjusted by AH) were similar. Additionally, compared to ground PM(10), we found that AH-calibrated AOD had narrower confidence intervals for all models and was more robust in estimating the current day and lag day effects. Our preliminary findings suggested that, with proper adjustment of meteorological factors, satellite AOD can be used directly to estimate the acute health impacts of ambient particles without prior calibrating to the sparse ground monitoring networks. PMID:23220016

  17. DNMT3a epigenetic program regulates the HIF-2α oxygen-sensing pathway and the cellular response to hypoxia

    PubMed Central

    Lachance, Gabriel; Uniacke, James; Audas, Timothy E.; Holterman, Chet E.; Franovic, Aleksandra; Payette, Josianne; Lee, Stephen

    2014-01-01

    Epigenetic regulation of gene expression by DNA methylation plays a central role in the maintenance of cellular homeostasis. Here we present evidence implicating the DNA methylation program in the regulation of hypoxia-inducible factor (HIF) oxygen-sensing machinery and hypoxic cell metabolism. We show that DNA methyltransferase 3a (DNMT3a) methylates and silences the HIF-2α gene (EPAS1) in differentiated cells. Epigenetic silencing of EPAS1 prevents activation of the HIF-2α gene program associated with hypoxic cell growth, thereby limiting the proliferative capacity of adult cells under low oxygen tension. Naturally occurring defects in DNMT3a, observed in primary tumors and malignant cells, cause the unscheduled activation of EPAS1 in early dysplastic foci. This enables incipient cancer cells to exploit the HIF-2α pathway in the hypoxic tumor microenvironment necessary for the formation of cellular masses larger than the oxygen diffusion limit. Reintroduction of DNMT3a in DNMT3a-defective cells restores EPAS1 epigenetic silencing, prevents hypoxic cell growth, and suppresses tumorigenesis. These data support a tumor-suppressive role for DNMT3a as an epigenetic regulator of the HIF-2α oxygen-sensing pathway and the cellular response to hypoxia. PMID:24817692

  18. Silicon-on-glass pore network micromodels with oxygen-sensing fluorophore films for chemical imaging and defined spatial structure.

    PubMed

    Grate, Jay W; Kelly, Ryan T; Suter, Jonathan; Anheier, Norm C

    2012-11-21

    Pore network microfluidic models were fabricated by a silicon-on-glass technique that provides the precision advantage of dry etched silicon while creating a structure that is transparent across all microfluidic channels and pores, and can be imaged from either side. A silicon layer is bonded to an underlying borosilicate glass substrate and thinned to the desired height of the microfluidic channels and pores. The silicon is then patterned and through-etched by deep reactive ion etching (DRIE), with the underlying glass serving as an etch stop. After bonding on a transparent glass cover plate, one obtains a micromodel in oxygen impermeable materials with water-wet surfaces where the microfluidic channels are transparent and structural elements such as the pillars creating the pore network are opaque. The advantageous features of this approach in a chemical imaging application are demonstrated by incorporating a Pt porphyrin fluorophore in a PDMS film serving as the oxygen-sensing layer and a bonding surface, or in a polystyrene film coated with a PDMS layer for bonding. The sensing of a dissolved oxygen gradient was demonstrated using fluorescence lifetime imaging, and it is shown that different matrix polymers lead to optimal use in different ranges of oxygen concentration. Imaging with the opaque pillars in between the observation direction and the continuous fluorophore film yields images that retain defined spatial structure in the sensor image. PMID:22995983

  19. Silicon-on-glass pore network micromodels with oxygen-sensing fluorophore films for chemical imaging and defined spatial structure

    SciTech Connect

    Grate, Jay W.; Kelly, Ryan T.; Suter, Jonathan D.; Anheier, Norman C.

    2012-11-21

    Pore network microfluidic models were fabricated by a silicon-on-glass technique that provides the precision advantage of dry etched silicon while creating a structure that is transparent across all microfluidic channels and pores, and can be imaged from either side. A silicon layer is bonded to an underlying borosilicate glass substrate and thinned to the desired height of the microfluidic channels and pores. The silicon is then patterned and through-etched by deep reactive ion etching (DRIE), with the underlying glass serving as an etch stop. After bonding on a transparent glass cover plate, one obtains a micromodel in oxygen impermeable materials with water wet surfaces where the microfluidic channels are transparent and structural elements such as the pillars creating the pore network are opaque. The micromodel can be imaged from either side. The advantageous features of this approach in a chemical imaging application are demonstrated by incorporating a Pt porphyrin fluorophore in a PDMS film serving as the oxygen sensing layer and a bonding surface, or in a polystyrene film coated with a PDMS layer for bonding. The sensing of a dissolved oxygen gradient was demonstrated using fluorescence lifetime imaging, and it is shown that different matrix polymers lead to optimal use in different ranges dissolved oxygen concentration. Imaging with the opaque pillars in between the observation direction and the continuous fluorophore film yields images that retain spatial information in the sensor image.

  20. Exceptional Oxygen Sensing Properties of New Blue Light-Excitable Highly Luminescent Europium(III) and Gadolinium(III) Complexes

    PubMed Central

    Borisov, Sergey M.; Fischer, Roland; Saf, Robert; Klimant, Ingo

    2016-01-01

    New europium(III) and gadolinium(III) complexes bearing 8-hydroxyphenalenone antenna combine efficient absorption in the blue part of the spectrum and strong emission in polymers at room temperature. The Eu(III) complexes show characteristic red luminescence whereas the Gd(III) dyes are strongly phosphorescent. The luminescence quantum yields are about 20% for the Eu(III) complexes and 50% for the Gd(III) dyes. In contrast to most state-of-the-art Eu(III) complexes the new dyes are quenched very efficiently by molecular oxygen. The luminescence decay times of the Gd(III) complexes exceed 1 ms which ensures exceptional sensitivity even in polymers of moderate oxygen permeability. These sensors are particularly suitable for trace oxygen sensing and may be good substitutes for Pd(II) porphyrins. The photophysical and sensing properties can be tuned by varying the nature of the fourth ligand. The narrow-band emission of the Eu(III) allows efficient elimination of the background light and autofluorescence and is also very attractive for use e.g. in multi-analyte sensors. The highly photostable indicators incorporated in nanoparticles are promising for imaging applications. Due to the straightforward preparation and low cost of starting materials the new dyes represent a promising alternative to the state-of-the-art oxygen indicators particularly for such applications as e.g. food packaging. PMID:27158252

  1. Preservation of high glycolytic phenotype by establishing new acute lymphoblastic leukemia cell lines at physiologic oxygen concentration.

    PubMed

    Sheard, Michael A; Ghent, Matthew V; Cabral, Daniel J; Lee, Joanne C; Khankaldyyan, Vazgen; Ji, Lingyun; Wu, Samuel Q; Kang, Min H; Sposto, Richard; Asgharzadeh, Shahab; Reynolds, C Patrick

    2015-05-15

    Cancer cells typically exhibit increased glycolysis and decreased mitochondrial oxidative phosphorylation, and they continue to exhibit some elevation in glycolysis even under aerobic conditions. However, it is unclear whether cancer cell lines employ a high level of glycolysis comparable to that of the original cancers from which they were derived, even if their culture conditions are changed to physiologically relevant oxygen concentrations. From three childhood acute lymphoblastic leukemia (ALL) patients we established three new pairs of cell lines in both atmospheric (20%) and physiologic (bone marrow level, 5%) oxygen concentrations. Cell lines established in 20% oxygen exhibited lower proliferation, survival, expression of glycolysis genes, glucose consumption, and lactate production. Interestingly, the effects of oxygen concentration used during cell line initiation were only partially reversible when established cell cultures were switched from one oxygen concentration to another for eight weeks. These observations indicate that ALL cell lines established at atmospheric oxygen concentration can exhibit relatively low levels of glycolysis and these levels are semi-permanent, suggesting that physiologic oxygen concentrations may be needed from the time of cell line initiation to preserve the high level of glycolysis commonly exhibited by leukemias in vivo. PMID:25845499

  2. Severe Acute Respiratory Failure due to Inhalation of Baby Powder and Successfully Treated with Venous-Venous Extracorporeal Membrane Oxygenation.

    PubMed

    Panarello, Giovanna; Occhipinti, Giovanna; Piazza, Marcello; Capitanio, Guido; Vitulo, Patrizio; Gridelli, Bruno; Pilato, Michele; Arcadipane, Antonio

    2015-12-15

    Accidental inhalation of powder is a potential problem for infants. The clinical effects of inhaling powder depend on the powder contents, degree of aspiration, and the child's underlying systemic response. We present a case of accidental inhalation of rice starch powder in a 17-month-old girl, which led to severe acute respiratory distress syndrome responsive to conventional treatment, ultimately requiring venous-venous extracorporeal membrane oxygenation. PMID:26657704

  3. Cardiac oxygen limitation during an acute thermal challenge in the European perch: effects of chronic environmental warming and experimental hyperoxia.

    PubMed

    Ekström, Andreas; Brijs, Jeroen; Clark, Timothy D; Gräns, Albin; Jutfelt, Fredrik; Sandblom, Erik

    2016-08-01

    Oxygen supply to the heart has been hypothesized to limit cardiac performance and whole animal acute thermal tolerance (CTmax) in fish. We tested these hypotheses by continuously measuring venous oxygen tension (Pvo2) and cardiovascular variables in vivo during acute warming in European perch (Perca fluviatilis) from a reference area during summer (18°C) and a chronically heated area (Biotest enclosure) that receives warm effluent water from a nuclear power plant and is normally 5-10°C above ambient (24°C at the time of experiments). While CTmax was 2.2°C higher in Biotest compared with reference perch, the peaks in cardiac output and heart rate prior to CTmax occurred at statistically similar Pvo2 values (2.3-4.0 kPa), suggesting that cardiac failure occurred at a common critical Pvo2 threshold. Environmental hyperoxia (200% air saturation) increased Pvo2 across temperatures in reference fish, but heart rate still declined at a similar temperature. CTmax of reference fish increased slightly (by 0.9°C) in hyperoxia, but remained significantly lower than in Biotest fish despite an improved cardiac output due to an elevated stroke volume. Thus, while cardiac oxygen supply appears critical to elevate stroke volume at high temperatures, oxygen limitation may not explain the bradycardia and arrhythmia that occur prior to CTmax Acute thermal tolerance and its thermal plasticity can, therefore, only be partially attributed to cardiac failure from myocardial oxygen limitations, and likely involves limiting factors on multiple organizational levels. PMID:27280433

  4. A new method to detect rapid oxygen changes around cells: How quickly do calcium channels sense oxygen in cardiomyocytes?

    PubMed Central

    Scaringi, John A.; Rosa, Angelo Oscar; Morad, Martin

    2013-01-01

    Acute hypoxia is thought to trigger protective responses that, in tissues like heart and carotid body, include rapid (5–10 s) suppression of Ca2+ and K+ channels. To gain insight into the mechanism for the suppression of the cardiac l-type Ca2+ channel, we measured O2-dependent fluorescence in the immediate vicinity of voltage-clamped cardiac cells subjected to rapid exchange of solutions with different O2 tensions. This was accomplished with an experimental chamber with a glass bottom that was used as a light guide for excitation of a thin ruthenium-based O2-sensitive ORMOSIL coating. Fluorescence imaging showed that steady-state Po2 was well controlled within the entire stream from an electromagnetically controlled solution “puffer” but that changes were slower at the periphery of the stream (τ1/2 ∼ 500 ms) than immediately around the voltage-clamped myocyte (τ1/2 ∼ 225 ms) where, in turn, firmly attached cells produced an additional local delay of 50–100 ms. Performing simultaneous voltage clamp and O2 measurements, we found that acute hypoxia gradually and reversibly suppressed the Ca2+ channel (CaV1.2). Using Ba2+ as charge carrier, the suppression was significant after 1.5 s, reached ∼10% after 2.5 s, and was nearly completely reversible in 5 s. The described fluorescence measurements provide the means to check and fine tune solution puffers and suggest that changes in Po2 can be accomplished within ∼200 ms. The rapid and reversible suppression of barium current under hypoxia is consistent with the notion that the cardiac Ca2+ channel is directly modulated by O2. PMID:24157525

  5. Predictors of Acute Renal Failure During Extracorporeal Membrane Oxygenation in Pediatric Patients After Cardiac Surgery.

    PubMed

    Lv, Lin; Long, Cun; Liu, Jinping; Hei, Feilong; Ji, Bingyang; Yu, Kun; Hu, Qiang; Hu, Jinxiao; Yuan, Yuan; Gao, Guodong

    2016-05-01

    Acute renal failure (ARF) is associated with increased mortality in pediatric extracorporeal membrane oxygenation (ECMO). The aim of this study was to identify predictors of ARF during ECMO in pediatric patients after cardiac surgery. A retrospective study analyzed 42 children (≤15 years) after cardiac surgery requiring venous-arterial ECMO between December 2008 and December 2014 at Fuwai Hospital. ARF was defined as ≥300% rise in serum creatinine (SCr) concentration from baseline or application of dialysis. Multivariate logistic regression was performed to identify the predictors of ARF during ECMO. A total of 42 children (age, interquartile range [IQR], 13.0 [7.2-29.8] months; weight, IQR, 8.5 [6.7-11.0] kg) after cardiac surgery requiring ECMO were included in this study. The total survival rate was 52.4%, and the incidence of ARF was 40.5%. As the result of univariate analysis, ECMO duration, cardiopulmonary resuscitation, maximum free hemoglobin (FHB) during ECMO, lactate level, and mean blood pressure before initiation of ECMO were entered in multiple logistic regression analysis. In multiple logistic regression analysis, FHB during ECMO (OR 1.136, 95% CI 1.023-1.261) and lactate level before initiation of ECMO (OR 1.602, 95% CI 1.025-2.502) were risk factors for ARF during ECMO after pediatric cardiac surgery. There was a linear correlation between maximum SCr and maximum FHB (Pearson's r = 0.535, P = 0.001). Maximum SCr during ECMO has also a linear correlation with lactate level before initiation of ECMO (Pearson's r = 0.342, P = 0.044). Increased FHB during ECMO and high lactate level before initiation of ECMO were risk factors for ARF during ECMO in pediatric patients after cardiac surgery. PMID:26636965

  6. Combined venoarterial extracorporeal membrane oxygenation and transcatheter aortic valve implantation for the treatment of acute aortic prosthesis dysfunction in a high-risk patient.

    PubMed

    Pergolini, Amedeo; Zampi, Giordano; Tinti, Maria Denitza; Polizzi, Vincenzo; Pino, Paolo Giuseppe; Pontillo, Daniele; Musumeci, Francesco; Luzi, Giampaolo

    2016-01-01

    We describe the case of a patient with acute bioprosthesis dysfunction in cardiogenic shock, in whom hemodynamic support was provided by venoarterial extracorporeal membrane oxygenation, and successfully treated by transcatheter aortic valve implantation. PMID:27402446

  7. Gas sensing in microplates with optodes: influence of oxygen exchange between sample, air, and plate material.

    PubMed

    Arain, Sarina; Weiss, Svenja; Heinzle, Elmar; John, Gernot T; Krause, Christian; Klimant, Ingo

    2005-05-01

    Microplates with integrated optical oxygen sensors are a new tool to study metabolic rates and enzyme activities. Precise measurements are possible only if oxygen exchange between the sample and the environment is known. In this study we quantify gas exchange in plastic microplates. Dissolved oxygen was detected using either an oxygen-sensitive film fixed at the bottom of each well or a needle-type sensor. The diffusion of oxygen into wells sealed with different foils, paraffin oil, and paraffin wax, respectively, was quantified. Although foil covers showed the lowest oxygen permeability, they include an inevitable gas phase between sample and sealing and are difficult to manage. The use of oil was found to be critical due to the extensive shaking caused by movement of the plates during measurements in microplate readers. Thus, paraffin wax was the choice material because it avoids convection of the sample and is easy to handle. Furthermore, without shaking, significant gradients in pO2 levels within a single well of a polystyrene microplate covered with paraffin oil were detected with the needle-type sensor. Higher pO2 levels were obtained near the surface of the sample as well as near the wall of the well. A significant diffusion of oxygen through the plastic plate material was found using plates based on polystyrene. Thus, the location of a sensor element within the well has an effect on the measured pO2 level. Using a sensor film fixed on the bottom of a well or using a dissolved pO2-sensitive indicator results in pO2 offset and in apparently lower respiration rates or enzyme activities. Oxygen diffusion through a polystyrene microplate was simulated for measurements without convection--that is, for samples without oxygen diffusion through the cover and for unshaken measurements using permeable sealings. This mathematical model allows for calculation of the correct kinetic parameters. PMID:15772950

  8. The regulation of pulmonary inflammation by the hypoxia-inducible factor-hydroxylase oxygen-sensing pathway.

    PubMed

    Whyte, Moira K B; Walmsley, Sarah R

    2014-12-01

    Although the hypoxia-inducible factor (HIF)-hydroxylase oxygen-sensing pathway has been extensively reviewed in the context of cellular responses to hypoxia and cancer biology, its importance in regulating innate immune biology is less well described. In this review, we focus on the role of the HIF-hydroxylase pathway in regulating myeloid cell responses and its relevance to inflammatory lung disease. The more specific roles of individual HIF/ prolyl hydroxylase pathway members in vivo are discussed in the context of lineage-specific rodent models of inflammation, with final reference made to the therapeutic challenges of targeting the HIF/hydroxylase pathway in immune cells. PMID:25525731

  9. Microwave-assisted synthesis of SnO2 nanorods for oxygen gas sensing at room temperature

    PubMed Central

    Azam, Ameer; Habib, Sami S; Salah, Numan A; Ahmed, Faheem

    2013-01-01

    High-quality single-crystalline SnO2 nanorods were synthesized using a microwave-assisted solution method. The nanorods were characterized using X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), ultraviolet-visible and Raman spectroscopy, Brunauer–Emmett–Teller (BET), and electrical resistance measurements. The XRD pattern indicated the formation of single-phase SnO2 nanorods with rutile structure. FE-SEM and TEM images revealed tetragonal nanorods of about 450–500 nm in length and 60–80 nm in diameter. The nanorods showed a higher BET surface area of 288 m2/g, much higher than that of previously reported work. The Raman scattering spectra indicated a typical rutile phase of the SnO2. The absorption spectrum showed an absorption peak centered at 340 nm, and the band-gap value was found to be 3.64 eV. The gas-sensing properties of the SnO2 nanorods for oxygen gas with different concentrations were measured at room temperature. It was found that the value of resistance increased with the increase in oxygen gas concentration in the test chamber. The SnO2 nanorods exhibited high sensitivity and rapid response-recovery characteristics to oxygen gas, and could detect oxygen concentration as low as 1, 3, 5, and 10 ppm. PMID:24143091

  10. Evaluation of Intrarenal Oxygenation in Iodinated Contrast-Induced Acute Kidney Injury–Susceptible Rats by Blood Oxygen Level–Dependent Magnetic Resonance Imaging

    PubMed Central

    Li, Lu-Ping; Lu, Jing; Zhou, Ying; Papadopoulou, Maria V.; Franklin, Tammy; Bokhary, Ujala; Solomon, Richard; Sen, Anindya; Prasad, Pottumarthi V.

    2016-01-01

    Objectives The objectives of this study were to evaluate differences in intrarenal oxygenation as assessed by blood oxygen level–dependent (BOLD) magnetic resonance imaging in contrast-induced acute kidney injury (CIAKI)–susceptible rats when using 4 contrast media with different physicochemical properties and to demonstrate the feasibility of acquiring urinary neutrophil gelatinase–associated lipocalin (NGAL) levels as a marker of CIAKI in this model. Materials and Methods Our institutional animal care and use committee approved the study. Sixty-six Sprague-Dawley rats were divided into CIAKI-susceptible groups (received nitric oxide synthase inhibitor N-nitro-L-arginine methyl ester [10 mg/kg] and cycloxygenase inhibitor indomethacin [10mg/kg]) and control groups (received saline instead). One of the 4 iodinated contrast agents (iothalamate, iohexol, ioxaglate, or iodixanol) was then administered (1600-mg organic iodine per kilogram of body weight). Multiple blood oxygen level–dependent magnetic resonance images were acquired on a Siemens 3.0-T scanner using a multiple gradient recalled echo sequence at baseline, after N-nitro-L-arginine methyl ester (or saline), indomethacin (or saline), and iodinated contrast agent (or placebo). R2* (R2* = 1/T2*) maps were generated inline on the scanner. A mixed-effects growth curve model with first-order autoregressive variance-covariance was used to analyze the temporal data. Urinary NGAL, a marker of kidney injury (unlike serum creatinine), was measured 4 hours after contrast injection in the 2 subgroups. Results Differences in blood oxygen level–dependent magnetic resonance imaging results between the contrast media were observed in all 4 renal regions. However, the inner stripe of the outer medulla (ISOM) showed the most pronounced changes in the CIAKI-susceptible group and R2* increased significantly (P < 0.01) over time with all 4 contrast media. In the control groups, only iodixanol showed an increase in R2

  11. Dissolved oxygen sensing using an optical fibre long period grating coated with hemoglobin

    NASA Astrophysics Data System (ADS)

    Partridge, M.; James, S. W.; Tatam, R. P.

    2015-09-01

    A method for the preparation of a sensor consisting of an optical fibre long period grating coated with human hemoglobin is described. The utility of this sensor in detecting dissolved oxygen in phosphate buffered saline solution, by the conversion of the coated hemoglobin from deoxyhemoglobin to oxyhemoglobin, is described. The sensor shows good repeatability with a %CV of less than 1% for oxygenated and deoxygenated states and no drift or hysteresis with repeated cycling.

  12. FIBER OPTICAL MICRO-DETECTORS FOR OXYGEN SENSING IN POWER PLANTS

    SciTech Connect

    Gregory L. Baker; Ruby N. Ghosh; D.J. Osborn III; Po Zhang

    2005-04-01

    A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. One of the critical materials issues is to demonstrate that the luminescent cluster immobilized in the sol-gel porous support can withstand high temperature. At the same time the sol-gel matrix must have a high permeability to oxygen. Using a potassium salt of the molybdenum clusters, K{sub 2}Mo{sub 6}Cl{sub 14}, we have established the conditions necessary for deposition of optical quality sol-gel films. From spectroscopic measurements of the film we have shown that the cluster luminescence is stable following heat cycling of 54 hours at 200 C. Quenching of a factor of 1.5X between pure nitrogen and 21% oxygen was observed from in-situ measurements of films heated directly at 200 C. An automated system for characterizing fiber optic oxygen sensors up to 220 C with a temporal resolution better than 10 s is under construction. We estimate a signal of 6 x 10{sup 8} photons/s after complete quenching in 21% oxygen. These are promising results for a high temperature fiber optical oxygen sensor based on molybdenum chloride clusters.

  13. The Stroke Oxygen Pilot Study: A Randomized Controlled Trial of the Effects of Routine Oxygen Supplementation Early after Acute Stroke—Effect on Key Outcomes at Six Months

    PubMed Central

    Ali, Khalid; Warusevitane, Anushka; Lally, Frank; Sim, Julius; Sills, Sheila; Pountain, Sarah; Nevatte, Tracy; Allen, Martin; Roffe, Christine

    2013-01-01

    Introduction Post-stroke hypoxia is common, and may adversely affect outcome. We have recently shown that oxygen supplementation may improve early neurological recovery. Here, we report the six-month outcomes of this pilot study. Methods Patients with a clinical diagnosis of acute stroke were randomized within 24 h of admission to oxygen supplementation at 2 or 3 L/min for 72 h or to control treatment (room air). Outcomes (see below) were assessed by postal questionnaire at 6 months. Analysis was by intention-to-treat, and statistical significance was set at p≤0.05. Results Out of 301 patients randomized two refused/withdrew consent and 289 (148 in the oxygen and 141 in the control group) were included in the analysis: males 44%, 51%; mean (SD) age 73 (12), 71 (12); median (IQR) National Institutes of Health Stroke Scale score 6 (3, 10), 5 (3, 10) for the two groups respectively. At six months 22 (15%) patients in the oxygen group and 20 (14%) in the control group had died; mean survival in both groups was 162 days (p = 0.99). Median (IQR) scores for the primary outcome, the modified Rankin Scale, were 3 (1, 5) and 3 (1, 4) for the oxygen and control groups respectively. The covariate-adjusted odds ratio was 1.04 (95% CI 0.67, 1.60), indicating that the odds of a lower (i.e. better) score were non-significantly higher in the oxygen group (p = 0.86). The mean differences in the ability to perform basic (Barthel Index) and extended activities of daily living (NEADL), and quality of life (EuroQol) were also non-significant. Conclusions None of the key outcomes differed at 6 months between the groups. Although not statistically significant and generally of small magnitude, the effects were predominantly in favour of the oxygen group; a larger trial, powered to show differences in longer-term functional outcomes, is now on-going. Trial Registration Controlled-Trials.com ISRCTN12362720; Eudract.ema.europa.eu 2004-001866-41 PMID:23755093

  14. Multi-modal in vivo imaging of brain blood oxygenation, blood flow and neural calcium dynamics during acute seizures

    NASA Astrophysics Data System (ADS)

    Ringuette, Dene; Jeffrey, Melanie A.; Carlen, Peter L.; Levi, Ofer

    2016-03-01

    Dysfunction of the vascular endothelium has been implicated in the development of epilepsy. To better understand the relation between vascular function and seizure and provide a foundation for interpreting results from functional imaging in chronic disease models, we investigate the relationship between intracellular calcium dynamics and local cerebral blood flow and blood oxygen saturation during acute seizure-like events and pharmacological seizure rescue. To probe the relation between the aforementioned physiological markers in an acute model of epilepsy in rats, we integrated three different optical modalities together with electrophysiological recordings: Laser speckle contrast imaging (LSCI) was used to study changes in flow speeds, Intrinsic optical signal imaging (IOSI) was used to monitor changes in oxygenated, de-oxygenated, and total hemoglobin concentration, and Calcium-sensitive dye imaging was used to monitor intracellular calcium dynamics. We designed a dedicated cortical flow chamber to remove superficial blood and dye resulting from the injection procedure, which reduced spurious artifacts. The near infrared light used for IOSI and LSCI was delivered via a light pipe integrated with the flow chamber to minimize the effect of fluid surface movement on illumination stability. Calcium-sensitive dye was injected via a glass electrode used for recording the local field potential. Our system allowed us to observe and correlate increases in intracellular calcium, blood flow and blood volume during seizure-like events and provide a quantitative analysis of neurovascular coupling changes associated with seizure rescue via injection of an anti-convulsive agent.

  15. Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants

    SciTech Connect

    Gregory L. Baker; Ruby N. Ghosh; D.J. Osborn III; Po Zhang

    2006-05-01

    A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. Previously we described a particle-in-binder approach to immobilizing the potassium salt of the molybdenum cluster, K{sub 2}Mo{sub 6}Cl{sub 14}, at the tips of optical fibers. Compared to previous methods, the particle-in-binder approach affords fibers with greatly improved mechanical properties. The response of the sensor to oxygen at 40, 70 and 100 C was measured in 2-21% gas phase oxygen. The normalized sensor signal is linear with molar oxygen concentration and fits the theoretical Stern-Volmer relationship. Although the sensitivity decreases with temperature, at 100 C the sensitivity is 160 [O{sub 2}]{sup -1}. These are promising results for a high temperature fiber optical oxygen sensor based on molybdenum chloride clusters.

  16. Amphiphilic Fluorinated Polymer Nanoparticle Film Formation and Dissolved Oxygen Sensing Application

    NASA Astrophysics Data System (ADS)

    Gao, Yu; Zhu, Huie; Yamamoto, Shunsuke; Miyashita, Tokuji; Mitsuishi, Masaya

    2016-04-01

    Fluorinated polymer nanoparticle films were prepared by dissolving amphiphilic fluorinated polymer, poly (N-1H, 1H-pentadecafluorooctylmethacrylamide) (pC7F15MAA) in two miscible solvents (AK-225 and acetic acid). A superhydrophobic and porous film was obtained by dropcasting the solution on substrates. With higher ratios of AK-225 to acetic acid, pC7F15MAA was densified around acetic acid droplets, leading to the formation of pC7F15MAA nanoparticles. The condition of the nanoparticle film preparation was investigated by varying the mixing ratio or total concentration. A highly sensitive dissolved oxygen sensor system was successfully prepared utilizing a smart surface of superhydrophobic and porous pC7F15MAA nanoparticle film. The sensitivity showed I0/I40 = 126 in the range of dissolved oxygen concentration of 0 ~ 40 mg L-1. The oxygen sensitivity was compared with that of previous reports.

  17. Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants

    SciTech Connect

    Gregory L. Baker; Ruby N. Ghosh; D.J. Osborn; Po Zhang

    2006-06-30

    A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. Our approach towards immobilizing the potassium salt of the molybdenum cluster, K{sub 2}Mo{sub 6}Cl{sub 14}, at the far end of an optical fiber is to embed the cluster in a thermally cured sol-gel matrix particle. This particle-in-binder approach affords fibers with greatly improved mechanical properties, as compared to previous approaches. The sensor was characterized in 2-21% gas phase oxygen at 40, 70 and 100 C. These are promising results for a high temperature fiber optical oxygen sensor based on molybdenum chloride clusters.

  18. Severe Tumor Lysis Syndrome and Acute Pulmonary Edema Requiring Extracorporeal Membrane Oxygenation Following Initiation of Chemotherapy for Metastatic Alveolar Rhabdomyosarcoma.

    PubMed

    Sanford, Ethan; Wolbrink, Traci; Mack, Jennifer; Grant Rowe, R

    2016-05-01

    We present an 8-year-old male with metastatic alveolar rhabdomyosarcoma (ARMS) who developed precipitous cardiopulmonary collapse with severe tumor lysis syndrome (TLS) 48 hr after initiation of chemotherapy. Despite no detectable pulmonary metastases, acute hypoxemic respiratory failure developed, requiring extracorporeal membrane oxygenation (ECMO). Although TLS has been reported in disseminated ARMS, this singular case of life-threatening respiratory deterioration developing after initiation of chemotherapy presented unique therapeutic dilemmas. We review the clinical aspects of this case, including possible mechanisms of respiratory failure, and discuss the role of ECMO utilization in pediatric oncology. PMID:26713672

  19. A 2.0 and 4.7 Heterodyne Spectrometer for Lower Thermospheric Wind, Temperature, and Atomic Oxygen Density Sensing

    NASA Astrophysics Data System (ADS)

    Yee, J.; Wu, D. L.; Mehdi, I.; Schlecht, E.; Demajistre, R.; Talaat, E. R.

    2013-12-01

    In this paper, we will present the concept of a high-sensitivity heterodyne spectrometer operating at Terahertz (THz) frequency for global lower thermospheric neutral wind, temperature and atomic oxygen density measurements from a low earth orbit. These critical measurements are needed to better understand underlying mechanisms of the upper atmospheric composition/dynamics/temperature variability and the role of neutral dynamics on the ionospheric variability. Currently, no reliable satellite remote sensing technique can provide these measurements globally in the critical 100-150 km altitude region with complete local time coverage and desired spatial resolution, precision and accuracy. The instrument, THz Limb Sounder (TLS), to be developed under NASA's Geospace Instrument Development and Enabling Science Program, is aimed to provide, for the first time, global neutral wind/temperature/density profile measurements during day and night, with focus at altitudes of 100-150 km where most of the ion-neutral energy/momentum couplings take place. The TLS concept extends the limb sounding technique employed by Microwave Limb Sounder (MLS) for density/temperature/wind measurements by resolving the Doppler line shape of atomic oxygen fine structure emission at 2.0 and 4.7 THz (145 and 63 microns). These two atomic oxygen line emissions are very bright and distributed nearly uniformly globally (at all latitudes including high latitude particle precipitation regions) and temporally (at all local times during both day and night), thus ideal for thermospheric remote sensing. The TLS instrument concept, measurement methodology, and the expected performance will be presented and discussed in this paper.

  20. The acute antinociceptive effect of hyperbaric oxygen is not accompanied by an increase in markers of oxidative stress

    PubMed Central

    Liu, Shulin; Shirachi, Donald Y.; Quock, Raymond M.

    2014-01-01

    Aims Exposure to hyperbaric oxygen (HBO2) causes an antinociceptive response in mice. However, breathing oxygen (O2) at an elevated pressure can potentially cause oxygen toxicity. The aim of this study was to identify the determinants of HBO2 antinociception and the toxicity profile of HBO2. Main methods Male NIH Swiss mice were assessed for acute antinociceptive responsiveness under room air or 100% O2 at 1.0 or 3.5 atmospheres absolute (ATA), using the acetic acid-induced abdominal constriction test. For the oxygen toxicity test, mice were exposed to 3.5 ATA oxygen for 11 min, 60 min, 60 min daily for 2 days (120 min) or 60 min daily for 4 days (240 min), then assessed by analyzing the levels of two oxidative stress markers, MDA (malondialdehyde) and protein carbonyl in brain, spinal cord and lung. Key Findings Only the combination of 100% O2 and 3.5 ATA caused significant antinociception. The antinociceptive effect of 100% O2 was pressure-dependent up to 3.5 ATA. In the oxygen toxicity test, mice exposed to HBO2 for different time intervals had levels of brain, spinal cord and lung MDA and protein carbonyl that were comparable to that of control animals exposed to room air. Significance Treatment with 100% O2 evokes a pressure-dependent antinociceptive effect. Since there was no significant increase in levels of the oxidative stress markers in the tested tissues, it is concluded HBO2 at 3.5 ATA produces antinociception in the absence of oxidative stress in mice. PMID:24418003

  1. Improvement of Oxygenation in Severe Acute Respiratory Distress Syndrome With High-Volume Continuous Veno-venous Hemofiltration

    PubMed Central

    Yang, Wenmin; Hong, Jie; Zeng, Qiyi; Tao, Jianping; Chen, Feiyan; Dang, Run; Liang, Yufeng; Wu, Zhiyuan; Yang, Yiyu

    2016-01-01

    The efficacy and therapeutic mechanisms of continuous renal replacement therapy (CRRT) for improvement of oxygenation in acute respiratory distress syndrome (ARDS) remain controversial. These questions were addressed by retrospective analysis of severe ARDS patients admitted to the pediatric intensive care unit of our hospital from 2009 to 2015 who received high-volume continuous veno-venous hemofiltration during mechanical ventilation. There was a significant improvement in partial oxygen pressure/fraction of inspired oxygen (PaO2/FiO2) 24 hours after CRRT onset compared with baseline (median change = 51.5; range = −19 to 450.5; P < .001) as well as decreases in FiO2, peak inspiratory pressure, positive end-expiratory pressure, and mean airway pressure (P < .05). The majority of patients had a negative fluid balance after 24 hours of CRRT. White blood cell (WBC) count decreased in the subgroup with high baseline WBC count (P < .05). PaO2/FiO2 was higher in ARDS patients with extrapulmonary etiology than in those with pulmonary etiology (P < .05). Improvement in oxygenation is likely related to both restoration of fluid balance and clearance of inflammatory mediators. PMID:27336018

  2. FIBER OPTICAL MICRO-DETECTORS FOR OXYGEN SENSING IN POWER PLANTS

    SciTech Connect

    Gregory L. Baker; Ruby N. Ghosh; D.J. Osborn III; Po Zhang

    2005-01-01

    A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. One of the critical materials issues is to demonstrate that the luminescent cluster immobilized in the sol-gel porous support can withstand high temperature. At the same time the sol-gel matrix must have a high permeability to oxygen. Using a potassium salt of the molybdenum clusters, K{sub 2}Mo{sub 6}Cl{sub 14}, we have established the conditions necessary for deposition of optical quality sol-gel films. From spectroscopic measurements of the film we have shown that the cluster luminescence is stable following heat cycling of 1 hour at 250 C. Quenching of a factor of 4X between pure nitrogen and 21% oxygen was observed for films cured directly at 200 C. These are promising results for a high temperature fiber optical oxygen sensor based on molybdenum chloride clusters.

  3. Human oxygen sensing may have origins in prokaryotic elongation factor Tu prolyl-hydroxylation

    PubMed Central

    Scotti, John S.; Leung, Ivanhoe K. H.; Ge, Wei; Bentley, Michael A.; Paps, Jordi; Kramer, Holger B.; Lee, Joongoo; Aik, WeiShen; Choi, Hwanho; Paulsen, Steinar M.; Bowman, Lesley A. H.; Loik, Nikita D.; Horita, Shoichiro; Ho, Chia-hua; Kershaw, Nadia J.; Tang, Christoph M.; Claridge, Timothy D. W.; Preston, Gail M.; McDonough, Michael A.; Schofield, Christopher J.

    2014-01-01

    The roles of 2-oxoglutarate (2OG)-dependent prolyl-hydroxylases in eukaryotes include collagen stabilization, hypoxia sensing, and translational regulation. The hypoxia-inducible factor (HIF) sensing system is conserved in animals, but not in other organisms. However, bioinformatics imply that 2OG-dependent prolyl-hydroxylases (PHDs) homologous to those acting as sensing components for the HIF system in animals occur in prokaryotes. We report cellular, biochemical, and crystallographic analyses revealing that Pseudomonas prolyl-hydroxylase domain containing protein (PPHD) contain a 2OG oxygenase related in structure and function to the animal PHDs. A Pseudomonas aeruginosa PPHD knockout mutant displays impaired growth in the presence of iron chelators and increased production of the virulence factor pyocyanin. We identify elongation factor Tu (EF-Tu) as a PPHD substrate, which undergoes prolyl-4-hydroxylation on its switch I loop. A crystal structure of PPHD reveals striking similarity to human PHD2 and a Chlamydomonas reinhardtii prolyl-4-hydroxylase. A crystal structure of PPHD complexed with intact EF-Tu reveals that major conformational changes occur in both PPHD and EF-Tu, including a >20-Å movement of the EF-Tu switch I loop. Comparison of the PPHD structures with those of HIF and collagen PHDs reveals conservation in substrate recognition despite diverse biological roles and origins. The observed changes will be useful in designing new types of 2OG oxygenase inhibitors based on various conformational states, rather than active site iron chelators, which make up most reported 2OG oxygenase inhibitors. Structurally informed phylogenetic analyses suggest that the role of prolyl-hydroxylation in human hypoxia sensing has ancient origins. PMID:25197067

  4. Protein kinase G-regulated production of H2S governs oxygen sensing.

    PubMed

    Yuan, Guoxiang; Vasavda, Chirag; Peng, Ying-Jie; Makarenko, Vladislav V; Raghuraman, Gayatri; Nanduri, Jayasri; Gadalla, Moataz M; Semenza, Gregg L; Kumar, Ganesh K; Snyder, Solomon H; Prabhakar, Nanduri R

    2015-04-21

    Reflexes initiated by the carotid body, the principal O2-sensing organ, are critical for maintaining cardiorespiratory homeostasis during hypoxia. O2 sensing by the carotid body requires carbon monoxide (CO) generation by heme oxygenase-2 (HO-2) and hydrogen sulfide (H2S) synthesis by cystathionine-γ-lyase (CSE). We report that O2 stimulated the generation of CO, but not that of H2S, and required two cysteine residues in the heme regulatory motif (Cys(265) and Cys(282)) of HO-2. CO stimulated protein kinase G (PKG)-dependent phosphorylation of Ser(377) of CSE, inhibiting the production of H2S. Hypoxia decreased the inhibition of CSE by reducing CO generation resulting in increased H2S, which stimulated carotid body neural activity. In carotid bodies from mice lacking HO-2, compensatory increased abundance of nNOS (neuronal nitric oxide synthase) mediated O2 sensing through PKG-dependent regulation of H2S by nitric oxide. These results provide a mechanism for how three gases work in concert in the carotid body to regulate breathing. PMID:25900831

  5. Low-cost microarray thin-film electrodes with ionic liquid gel-polymer electrolytes for miniaturised oxygen sensing.

    PubMed

    Lee, Junqiao; Silvester, Debbie S

    2016-06-21

    A robust, miniaturised electrochemical gas sensor for oxygen (O2) has been constructed using a commercially available Pt microarray thin-film electrode (MATFE) with a gellified electrolyte containing the room temperature ionic liquid (RTIL) 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C2mim][NTf2]) and poly(methyl methacrylate) (PMMA) in a 50 : 50 mass ratio. Diffusion coefficients and solubilities for oxygen in mixtures of PMMA/RTIL at different PMMA doping concentrations (0-50% mass) were derived from potential step chronoamperometry (PSCA) on a Pt microdisk electrode. The MATFE was then used with both the neat RTIL and 50% (by mass) PMMA/RTIL gel, to study the analytical behavior over a wide concentration range (0.1 to 100 vol% O2). Cyclic voltammetry (CV) and long-term chronoamperometry (LTCA) techniques were employed and it was determined that the gentler CV technique is better at higher O2 concentrations (above 60 vol%), but LTCA is more reliable and accurate at lower concentrations (especially below 0.5% O2). In particular, there was much less potential shifting (from the unstable Pt quasi-reference electrode) evident in the 50% PMMA/RTIL gel than in the neat RTIL, making this a much more suitable electrolyte for long-term continuous oxygen monitoring. The mass production and low-cost of the electrode array, along with the minimal amounts of RTIL/PMMA required, make this a viable sensing device for oxygen detection on a bulk scale in a wide range of environmental conditions. PMID:26931642

  6. Modulation of Type I Interferon-Associated Viral Sensing during Acute Simian Immunodeficiency Virus Infection in African Green Monkeys

    PubMed Central

    Jochems, Simon P.; Petitjean, Gaël; Kunkel, Désirée; Liovat, Anne-Sophie; Ploquin, Mickaël J.; Barré-Sinoussi, Françoise; Lebon, Pierre; Jacquelin, Béatrice

    2014-01-01

    ABSTRACT Natural hosts of simian immunodeficiency virus (SIV), such as African green monkeys (AGMs), do not progress to AIDS when infected with SIV. This is associated with an absence of a chronic type I interferon (IFN-I) signature. It is unclear how the IFN-I response is downmodulated in AGMs. We longitudinally assessed the capacity of AGM blood cells to produce IFN-I in response to SIV and herpes simplex virus (HSV) infection. Phenotypes and functions of plasmacytoid dendritic cells (pDCs) and other mononuclear blood cells were assessed by flow cytometry, and expression of viral sensors was measured by reverse transcription-PCR. pDCs displayed low BDCA-2, CD40, and HLA-DR expression levels during AGM acute SIV (SIVagm) infection. BDCA-2 was required for sensing of SIV, but not of HSV, by pDCs. In acute infection, AGM peripheral blood mononuclear cells (PBMCs) produced less IFN-I upon SIV stimulation. In the chronic phase, the production was normal, confirming that the lack of chronic inflammation is not due to a sensing defect of pDCs. In contrast to stimulation by SIV, more IFN-I was produced upon HSV stimulation of PBMCs isolated during acute infection, while the frequency of AGM pDCs producing IFN-I upon in vitro stimulation with HSV was diminished. Indeed, other cells started producing IFN-I. This increased viral sensing by non-pDCs was associated with an upregulation of Toll-like receptor 3 and IFN-γ-inducible protein 16 caused by IFN-I in acute SIVagm infection. Our results suggest that, as in pathogenic SIVmac infection, SIVagm infection mobilizes bone marrow precursor pDCs. Moreover, we show that SIV infection modifies the capacity of viral sensing in cells other than pDCs, which could drive IFN-I production in specific settings. IMPORTANCE The effects of HIV/SIV infections on the capacity of plasmacytoid dendritic cells (pDCs) to produce IFN-I in vivo are still incompletely defined. As IFN-I can restrict viral replication, contribute to inflammation

  7. EDTA-Decorated Nanostructured ZnO/CdS Thin Films for Oxygen Gas Sensing Applications

    NASA Astrophysics Data System (ADS)

    Arunraja, L.; Thirumoorthy, P.; Karthik, A.; Rajendran, V.; Edwinpaul, L.

    2016-08-01

    ZnO/CdS and ZnO/CdS-EDTA nanostructured thin films were prepared on a glass substrate using spin-coating and used for oxygen gas sensor applications. The structural properties of both ZnO/CdS and ZnO/CdS-EDTA nanostructured composites were comparatively characterized. The nanostructure thin film was found in a hexagonal structure with an average crystallite size reduced from 77 nm to 29 nm due to the influence of the EDTA. The optical absorption, photo luminescence, functional groups and surface morphology of the nanostructured thin films were comprehensively investigated. Oxygen was suitably tailored to verify the sensor response over a concentration range of 10-50 ppm at room temperature. Thus, the sensor studies reveal that the performance, response, and recovery time were enhanced in ZnO/CdS-EDTA nanostructured thin film compared with ZnO/CdS.

  8. Chromatin and oxygen sensing in the context of JmjC histone demethylases

    PubMed Central

    Shmakova, Alena; Batie, Michael; Druker, Jimena; Rocha, Sonia

    2014-01-01

    Responding appropriately to changes in oxygen availability is essential for multicellular organism survival. Molecularly, cells have evolved intricate gene expression programmes to handle this stressful condition. Although it is appreciated that gene expression is co-ordinated by changes in transcription and translation in hypoxia, much less is known about how chromatin changes allow for transcription to take place. The missing link between co-ordinating chromatin structure and the hypoxia-induced transcriptional programme could be in the form of a class of dioxygenases called JmjC (Jumonji C) enzymes, the majority of which are histone demethylases. In the present review, we will focus on the function of JmjC histone demethylases, and how these could act as oxygen sensors for chromatin in hypoxia. The current knowledge concerning the role of JmjC histone demethylases in the process of organism development and human disease will also be reviewed. PMID:25145438

  9. Determination of atomic oxygen density and temperature of the thermosphere by remote sensing

    NASA Astrophysics Data System (ADS)

    Sharma, Ramesh D.; Harlow, Harry B.; Riehl, James P.

    1988-06-01

    Measurement of emission from the earth's atmosphere in the far infrared due to transitions between fine structure levels of the ground state (3P) of atomic oxygen at 63 microns, (3P1 to 3P2) and 147 microns (3P0 to 3P1) is proposed. These magnetic-dipole allowed transitions with long radiative lifetimes (about 3.2 h for the 63 micron transition and about 16.3 h for the 147 micron transition) are assumed to be in equilibrium with the local translational temperature. A one-dimensional onion-peel inversion of the limb emissions at 63 and 147 microns from a model atmosphere is shown to yield reasonable results for both the temperature and atomic oxygen density in the 90-250 km altitude range.

  10. Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants

    SciTech Connect

    Gregory L. Baker; Ruby N. Ghosh; D. J. Osborn; Po Zhang

    2006-09-30

    A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. Our approach towards immobilizing the potassium salt of the molybdenum cluster, K{sub 2}Mo{sub 6}Cl{sub 14}, at the far end of an optical fiber is to embed the cluster in a thermally cured sol-gel matrix particle. Due to the improved mechanical properties of this approach high temperature sensor measurements were performed up to 100 C. These are promising results for a high temperature fiber optical oxygen sensor based on molybdenum chloride clusters.

  11. Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants

    SciTech Connect

    Gregory L. Baker; Ruby N. Ghosh; D.J. Osborn III; Po Zhang

    2006-01-01

    A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. Previously we described a particle-in-binder approach to immobilizing the potassium salt of a molybdenum cluster, K{sub 2}Mo{sub 6}Cl{sub 14}, at the tips of optical fibers. Compared to previous methods, the particle-in-binder approach affords fibers with greatly improved mechanical properties. We have extensively characterized two fiber sensors at high temperature. We obtain quenching ratios between pure nitrogen and 21% oxygen as high as 3.9 x at 70 C. For the first sensor at 60 C we obtained a {+-} 1% variation in the quenching ratio over 6 cycles of measurement, and monitored the device performance over 23 days. We were able to operate the second sensor continuously for 14 hours at 70 C, and the sensor quenching ratio was stable to 5% over that time period. These are promising results for a high temperature fiber optical oxygen sensor based on molybdenum chloride clusters.

  12. Analytical and mechanistic aspects of the room temperature phosphorescence of Erythrosine B adsorbed on solid supports as oxygen sensing phases

    NASA Astrophysics Data System (ADS)

    Velasco-García, Nieves; Pereiro-García, Rosario; Diaz-García, Marta E.

    1995-05-01

    Room temperature phosphorescence (RTP) lifetime measurements and spectra of different concentrations of Erythrosine B immobilized on anion exchangers and non-ionic resins have been employed to unveil mechanistic aspects of the RTP of immobilized Erythrosine B. The existence of a definite number of RTP decaying components in some experimental conditions has been confirmed. The effects of humidified argon and air on RTP lifetimes and the changes in luminescence intensities were used to investigate some of the interactions responsible for the multiple component RTP emission. The experiments performed also proved the suitability of the phases prepared using non-ionic resins, for the quantification of molecular oxygen by RTP-quenching measurements. Moreover, the solid phases with anion-exchanger resins showed good potential for the analytical sensing of humidity.

  13. Role of ammonia, inflammation, and cerebral oxygenation in brain dysfunction of acute-on-chronic liver failure patients.

    PubMed

    Sawhney, Rohit; Holland-Fischer, Peter; Rosselli, Matteo; Mookerjee, Rajeshwar P; Agarwal, Banwari; Jalan, Rajiv

    2016-06-01

    Hepatic encephalopathy (HE) is a common feature of acute-on-chronic liver failure (ACLF). Although ammonia, inflammation, and cerebral oxygenation are associated with HE in acute liver failure, their roles in ACLF are unknown. The aim of this prospective, longitudinal study was to determine the role of these pathophysiological variables in ACLF patients with and without HE. We studied 101 patients with ACLF admitted to the intensive care unit. Severity of ACLF and HE, arterial ammonia, jugular venous oxygen saturation (JVO2 ), white blood cell count (WCC), and C-reactive protein were measured at days 0, 1, 3, and 7. Patients were followed until death or hospital discharge. Mortality was high (51 patients, 50.5%), especially in patients with HE of whom 35 of 53 (66.0%) died regardless of ACLF severity. At baseline, increased WCC and abnormal JVO2 (high or low) were independent predictors of death. Further deterioration in inflammation, JVO2 , and ammonia were also predictive of mortality. JVO2 deviation and hyperammonemia were associated with the presence and severity of HE; improvement in these parameters was associated with a reduction in HE grade. No direct interaction was observed between these variables in regards to mortality or HE. In conclusion, this study describes potential mechanisms of HE in ACLF indicating that ammonia and abnormal cerebral oxygenation are important. The results suggest that ammonia, JVO2 , and WCC are important prognostic biomarkers and therapeutic targets. The relative roles of these pathophysiological factors in the pathogenesis of HE in ACLF or guiding therapy to improve survival requires future study. Liver Transplantation 22 732-742 2016 AASLD. PMID:27028317

  14. Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants

    SciTech Connect

    Gregory L. Baker; Ruby N. Ghosh; D. J. Osborn

    2003-09-30

    Spectroscopy of Mo{sub 6}Cl{sub 12} immobilized in a sol-gel matrix and heated to 200 C has been performed. Oxygen quenching of the luminescence was observed. Aging Mo{sub 6}Cl{sub 12} to temperatures above 250 C converts the canary yellow Mo{sub 6}Cl{sub 12} to a non-luminescent gray solid. Preliminary experiments point to oxidation of the clusters as the likely cause of thermally induced changes in the physical and optical properties of the clusters.

  15. Space Shuttle Orbiter oxygen partial pressure sensing and control system improvements

    NASA Technical Reports Server (NTRS)

    Frampton, Robert F.; Hoy, Dennis M.; Kelly, Kevin J.; Walleshauser, James J.

    1992-01-01

    A program aimed at developing a new PPO2 oxygen sensor and a replacement amplifier for the Space Shuttle Orbiter is described. Experimental design methodologies used in the test and modeling process made it possible to enhance the effectiveness of the program and to reduce its cost. Significant cost savings are due to the increased lifetime of the basic sensor cell, the maximization of useful sensor life through an increased amplifier gain adjustment capability, the use of streamlined production processes for the manufacture of the assemblies, and the refurbishment capability of the replacement sensor.

  16. FIBER OPTICAL MICRO-DETECTORS FOR OXYGEN SENSING IN POWER PLANTS

    SciTech Connect

    Gregory L. Baker; Ruby N. Ghosh; D.J. Osborn III

    2004-10-01

    A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. High temperature measurements of the emission of clusters in sol gel films show that the luminescence intensity from the films follow a 1/T relationship from room temperature to 150 C, and then declines at a slower rate at higher temperatures. The large number of photons available at 230 C is consistent with simple low cost optics for fiber optic probes based on the emission from clusters in sol gel films.

  17. Oxygen consumption and haematology of juvenile shortnose sturgeon Acipenser brevirostrum during an acute 24 h saltwater challenge.

    PubMed

    Penny, F M; Kieffer, J D

    2014-04-01

    This study focused on the acute physiological responses to saltwater exposure in juvenile shortnose sturgeon Acipenser brevirostrum. In two separate laboratory experiments, 2 year-old A. brevirostrum were exposed to either full (32) or half-strength (16) seawater for up to 24 h. First, oxygen consumption rates were used to estimate the metabolic costs over 24 h. Secondly, blood and muscle samples were analysed at 6, 12 and 24 h for water loss, various measures of osmoregulatory status (plasma osmolality and ions) and other standard haematological variables. Juveniles exposed to full-strength seawater showed significant decreases in oxygen consumption rates during the 24 h exposure. Furthermore, seawater-exposed fish had significantly increased plasma osmolality, ions (Na(+) and Cl(-)) and a 17% decrease in total wet mass over the 24 h exposure period. To a lesser extent, increases in osmolality, ions and mass loss were observed in fish exposed to half-strength seawater but no changes to oxygen consumption. Cortisol was also significantly increased in fish exposed to full-strength seawater. While plasma protein was elevated following 24 h in full-strength seawater, haemoglobin, haematocrit and plasma glucose levels did not change with increased salinity. These results imply an inability of juvenile A. brevirostrum to regulate water and ions in full-strength seawater within 24 h. Nonetheless, no mortality occurred in any exposure, suggesting that juvenile A. brevirostrum can tolerate short periods in saline environments. PMID:24628001

  18. Acute effects of ferumoxytol on regulation of renal hemodynamics and oxygenation

    PubMed Central

    Cantow, Kathleen; Pohlmann, Andreas; Flemming, Bert; Ferrara, Fabienne; Waiczies, Sonia; Grosenick, Dirk; Niendorf, Thoralf; Seeliger, Erdmann

    2016-01-01

    The superparamagnetic iron oxide nanoparticle ferumoxytol is increasingly used as intravascular contrast agent in magnetic resonance imaging (MRI). This study details the impact of ferumoxytol on regulation of renal hemodynamics and oxygenation. In 10 anesthetized rats, a single intravenous injection of isotonic saline (used as volume control) was followed by three consecutive injections of ferumoxytol to achieve cumulative doses of 6, 10, and 41 mg Fe/kg body mass. Arterial blood pressure, renal blood flow, renal cortical and medullary perfusion and oxygen tension were continuously measured. Regulation of renal hemodynamics and oxygenation was characterized by dedicated interventions: brief periods of suprarenal aortic occlusion, hypoxia, and hyperoxia. None of the three doses of ferumoxytol resulted in significant changes in any of the measured parameters as compared to saline. Ferumoxytol did not significantly alter regulation of renal hemodynamics and oxygenation as studied by aortic occlusion and hypoxia. The only significant effect of ferumoxytol at the highest dose was a blunting of the hyperoxia-induced increase in arterial pressure. Taken together, ferumoxytol has only marginal effects on the regulation of renal hemodynamics and oxygenation. This makes ferumoxytol a prime candidate as contrast agent for renal MRI including the assessment of renal blood volume fraction. PMID:27436132

  19. Acute effects of ferumoxytol on regulation of renal hemodynamics and oxygenation.

    PubMed

    Cantow, Kathleen; Pohlmann, Andreas; Flemming, Bert; Ferrara, Fabienne; Waiczies, Sonia; Grosenick, Dirk; Niendorf, Thoralf; Seeliger, Erdmann

    2016-01-01

    The superparamagnetic iron oxide nanoparticle ferumoxytol is increasingly used as intravascular contrast agent in magnetic resonance imaging (MRI). This study details the impact of ferumoxytol on regulation of renal hemodynamics and oxygenation. In 10 anesthetized rats, a single intravenous injection of isotonic saline (used as volume control) was followed by three consecutive injections of ferumoxytol to achieve cumulative doses of 6, 10, and 41 mg Fe/kg body mass. Arterial blood pressure, renal blood flow, renal cortical and medullary perfusion and oxygen tension were continuously measured. Regulation of renal hemodynamics and oxygenation was characterized by dedicated interventions: brief periods of suprarenal aortic occlusion, hypoxia, and hyperoxia. None of the three doses of ferumoxytol resulted in significant changes in any of the measured parameters as compared to saline. Ferumoxytol did not significantly alter regulation of renal hemodynamics and oxygenation as studied by aortic occlusion and hypoxia. The only significant effect of ferumoxytol at the highest dose was a blunting of the hyperoxia-induced increase in arterial pressure. Taken together, ferumoxytol has only marginal effects on the regulation of renal hemodynamics and oxygenation. This makes ferumoxytol a prime candidate as contrast agent for renal MRI including the assessment of renal blood volume fraction. PMID:27436132

  20. [Use of steam-oxygen tents with a universal steam generator and automatic control system in the treatment of acute stenosing laryngotracheitis in children].

    PubMed

    Taĭts, B M

    1993-01-01

    To treat acute stenosing laryngotracheitis in acute respiratory viral infection in children an original method has been developed and used for 2 years in a special hospital department. The method implies treatment of children in steam-and-oxygen tents with a universal steam-moistening generator and automatic control system. A controlled study of 50 children with acute laryngeal stenosis degree I-III confirmed high efficacy of this method permitting improvement of blood oxygenation, gas composition, acid-base condition, reduction of acidosis, prevention of exicosis and brain edema. Warm humid atmosphere promoted better discharge of the secretion and better functioning of the ciliated epithelium. Combined treatment incorporating the tents in acute laryngeal stenoses reduced lethality in severe cases, number of intubations and tracheostomies, of complications resultant from parenteral administration of the drugs. PMID:8009767

  1. Primary endosymbiosis and the evolution of light and oxygen sensing in photosynthetic eukaryotes

    PubMed Central

    Rockwell, Nathan C.; Lagarias, J. Clark; Bhattacharya, Debashish

    2015-01-01

    The origin of the photosynthetic organelle in eukaryotes, the plastid, changed forever the evolutionary trajectory of life on our planet. Plastids are highly specialized compartments derived from a putative single cyanobacterial primary endosymbiosis that occurred in the common ancestor of the supergroup Archaeplastida that comprises the Viridiplantae (green algae and plants), red algae, and glaucophyte algae. These lineages include critical primary producers of freshwater and terrestrial ecosystems, progenitors of which provided plastids through secondary endosymbiosis to other algae such as diatoms and dinoflagellates that are critical to marine ecosystems. Despite its broad importance and the success of algal and plant lineages, the phagotrophic origin of the plastid imposed an interesting challenge on the predatory eukaryotic ancestor of the Archaeplastida. By engulfing an oxygenic photosynthetic cell, the host lineage imposed an oxidative stress upon itself in the presence of light. Adaptations to meet this challenge were thus likely to have occurred early on during the transition from a predatory phagotroph to an obligate phototroph (or mixotroph). Modern algae have recently been shown to employ linear tetrapyrroles (bilins) to respond to oxidative stress under high light. Here we explore the early events in plastid evolution and the possible ancient roles of bilins in responding to light and oxygen. PMID:25729749

  2. FIBER OPTICAL MICRO-DETECTORS FOR OXYGEN SENSING IN POWER PLANTS

    SciTech Connect

    Gregory L. Baker; Ruby N. Ghosh; D.J. Osborn III

    2003-07-01

    Mo{sub 6}Cl{sub 12}, a cluster compound whose luminescence depends on the ambient concentration of oxygen, is the basis for a real-time oxygen sensor for combustion applications. Previously, the properties of Mo{sub 6}Cl{sub 12} have largely been studied at room temperature; these studies have now been extended to 200 C. Optical microscopy shows that Mo{sub 6}Cl{sub 12} undergoes a steady change in color as it is heated from room temperature to 200 C, changing from canary yellow to crimson and then back to canary yellow. Concurrent thermal gravimetric analyses show a small weight loss for Mo{sub 6}Cl{sub 12} that is consistent with loss of water or HCl from the clusters. These changes are reversible. Absorption and fluorescence emission spectroscopy of Mo{sub 6}Cl{sub 12} heated to 200 C for two hours shows no change in the photophysical parameters compared to the control sample that was not heat cycled.

  3. Synthesis, processing and characterization of calcia-stabilized zirconia solid electrolytes for oxygen sensing applications

    SciTech Connect

    Zhou Minghua . E-mail: mzhou@nrcan.gc.ca; Ahmad, Aftab

    2006-04-13

    Precursor powders of calcia-stabilized zirconia (CSZ) solid electrolytes have been synthesized by a sol-gel method. The phase evolution of the precursor powders after thermal treatments at different temperatures were analysized by X-ray diffraction technique. Disc-shaped sensor elements were fabricated via uniaxial pressing of the calcined powders and subsequently sintered at 1650 deg. C. Scanning electron microscopy (SEM) was used to analyze the microstructure of the sintered pellets. Platinum electrodes were applied to the sintered elements to produce potentiometric/electrochemical gas sensors. The electrical response of the gas sensors to oxygen and the complex impedance of the sensors in air were measured at various temperatures. Impedance analyses indicate that the sensor cell with 15 mol% CaO has much lower resistance (the sum of bulk and grain-boundary resistance) than the sensor cell with 22 mol% CaO. This is also reflected by the EMF responses of both sensor cells to various oxygen concentrations in the testing gas. The EMF deviation from the theoretical value of the CSZ sensor cell with 22 mol% CaO was larger than that of the CSZ sensor cell with 15 mol% CaO. The corrrelations between material compositions, microstructures of the sintered pellets and the electrical properties of the sensors are discussed.

  4. Study on a phosphorescent copper(I) complex and its oxygen-sensing performances upon polystyrene and MCM-41 matrixes

    NASA Astrophysics Data System (ADS)

    Xu, Xiao-yong; Xiao, Han-ning; Xu, Yi-ming; Zhang, Ming-jun

    In this paper, we synthesize a new ligand of 1-ethyl-2-(naphthalen-1-yl)-1H-imidazo[4,5-f][1,10]phenanthroline (Phen-Np-Et) and its corresponding Cu(I) complex of [Cu(Phen-Np-Et)(POP)]BF4, where POP is bis(2-(diphenylphosphanyl)phenyl) ether. The single-crystal structure, electronic nature and photophysical property of [Cu(Phen-Np-Et)(POP)]BF4 are discussed in detail. It is found that the yellow emission from [Cu(Phen-Np-Et)(POP)]BF4 owns a long excited state lifetime of 287 μs under pure N2 atmosphere. Theoretical calculation on [Cu(Phen-Np-Et)(POP)]+ suggests that the emission comes from a triplet metal-to-ligand-charge-transfer excited state. Then, [Cu(Phen-Np-Et)(POP)]BF4 are doped into two matrixes of polystyrene and MCM-41 to investigate the oxygen-sensing performance. Finally, sensitivity maxima of 9.6 and 3.6 are achieved by the composite nanofibers of [Cu(Phen-Np-Et)(POP)]BF4/polystyrene and the [Cu(Phen-Np-Et)(POP)]BF4/MCM-41, respectively. Both samples are highly sensitive toward molecular oxygen, owing to the large surface-area-to-volume ratios of nanofibrous membranes and MCM-41 matrix.

  5. Iodine-mediated etching of gold nanorods for plasmonic sensing of dissolved oxygen and salt iodine.

    PubMed

    Zhang, Zhiyang; Chen, Zhaopeng; Cheng, Fangbin; Zhang, Yaowen; Chen, Lingxin

    2016-05-10

    Here, we have carefully investigated iodine-mediated etching of gold nanorods (AuNRs) in the presence of iodate and applied this phenomenon to on-site detection of dissolved oxygen (DO). Under given conditions, the quantitative conversion of target analytes DO to iodine leads to the etching of AuNRs along the longitudinal direction with the aid of cetyltrimethylammonium. As a result, the longitudinal localized surface plasmon resonance shifts to a short wavelength. The peak-shift can be used for quantitative determination of DO and iodate by a spectrophotometer. The satisfactory results from DO detection in different water samples and iodate detection in table salt indicate the feasibility of the proposed methods. Moreover, the as-prepared colorimetric test paper would make the detection more economical and simpler. PMID:27049138

  6. The Role of Hypoxia-Inducible Factors in Oxygen Sensing by the Carotid Body

    PubMed Central

    Prabhakar, Nanduri R.

    2013-01-01

    Chronic intermittent hypoxia (IH) associated with sleep-disordered breathing is an important cause of hypertension, which results from carotid body-mediated activation of the sympathetic nervous system. IH triggers increased levels of reactive oxygen species (ROS) in the carotid body, which induce increased synthesis and stability of hypoxia-inducible factor 1α (HIF-1α) and calpain-dependent degradation of HIF-2α. HIF-1 activates transcription of the Nox2 gene, encoding NADPH oxidase 2, which generates superoxide. Loss of HIF-2 activity leads to decreased transcription of the Sod2 gene, encoding manganese superoxide dismutase, which converts superoxide to hydrogen peroxide. Thus, IH disrupts the balance between HIF-1-dependent pro-oxidant and HIF-2-dependent anti-oxidant activities, and this loss of redox homeostasis underlies the pathogenesis of autonomic morbidities associated with IH. PMID:23080136

  7. Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants

    SciTech Connect

    Gregory L. Baker; Ruby N. Ghosh; D.J. Osborn III; Po Zhang

    2005-10-01

    A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. Previously we immobilized the potassium salt of a molybdenum cluster, K{sub 2}M{sub 6}Cl{sub 14}, in a sol-gel matrix and showed that the luminescence is stable after 54 hours at 200 C, but the quenching ratios were low and the films delaminated after thermal cycling due to densification of the matrix. Three new approaches to solve decreased quenching over time and delamination of films off fiber tips were investigated. In the first approach K{sub 2}Mo{sub 6}Cl{sub 14} embedded in cured sol-gel particles were incorporated into a TEOS based sol-gel. These gave enhanced quenching (6x), but delaminated. Our second approach was to use a commercial cyanoacrylate glue to immobilize the particles onto the tip of an optical fiber. This gave better adhesion and good quenching initially, but eventually the glue degraded upon heating. Our third approach was to use a 55% OtMOS/ TEOS sol-gel binder. Films based on this new sol-gel binder show high quenching ({approx}6x) and superior mechanical stability even after thermal cycling. Sensor measurements on an optical fiber containing K{sub 2}Mo{sub 6}Cl{sub 14} embedded in cured sol-gel particles were obtained from 100 to 25 C. The signal intensity in nitrogen was stable at 2.8 {+-} 0.2 nW, and the quenching ratio (ratio of signal in N{sub 2} vs. 21 % O{sub 2}) varied from 4.4 to 6.9X. These are promising results for a high temperature fiber optical oxygen sensor based on molybdenum chloride clusters.

  8. Hyperbaric oxygen therapy in the management of severe acute anaemia in a Jehovah's witness.

    PubMed

    McLoughlin, P L; Cope, T M; Harrison, J C

    1999-09-01

    A case is described in which a Jehovah's Witness patient who refused blood transfusion suffered massive antepartum haemorrhage, her haemoglobin falling as low as 2.0 g.dl(-1). She was treated on an intensive care unit with intermittent positive pressure ventilation and general supportive measures, pulsed hyperbaric oxygen therapy and recombinant human erythropoietin. PMID:10460565

  9. Intra-breath arterial oxygen oscillations detected by a fast oxygen sensor in an animal model of acute respiratory distress syndrome

    PubMed Central

    Formenti, F.; Chen, R.; McPeak, H.; Murison, P. J.; Matejovic, M.; Hahn, C. E. W.; Farmery, A. D.

    2015-01-01

    Background There is considerable interest in oxygen partial pressure (Po2) monitoring in physiology, and in tracking Po2 changes dynamically when it varies rapidly. For example, arterial Po2 (PaO2) can vary within the respiratory cycle in cyclical atelectasis (CA), where PaO2 is thought to increase and decrease during inspiration and expiration, respectively. A sensor that detects these PaO2 oscillations could become a useful diagnostic tool of CA during acute respiratory distress syndrome (ARDS). Methods We developed a fibreoptic Po2 sensor (<200 µm diameter), suitable for human use, that has a fast response time, and can measure Po2 continuously in blood. By altering the inspired fraction of oxygen (FIO2) from 21 to 100% in four healthy animal models, we determined the linearity of the sensor's signal over a wide range of PaO2 values in vivo. We also hypothesized that the sensor could measure rapid intra-breath PaO2 oscillations in a large animal model of ARDS. Results In the healthy animal models, PaO2 responses to changes in FIO2 were in agreement with conventional intermittent blood-gas analysis (n=39) for a wide range of PaO2 values, from 10 to 73 kPa. In the animal lavage model of CA, the sensor detected PaO2 oscillations, also at clinically relevant PaO2 levels close to 9 kPa. Conclusions We conclude that these fibreoptic PaO2 sensors have the potential to become a diagnostic tool for CA in ARDS. PMID:25631471

  10. Massive Systemic Air Embolism during Extracorporeal Membrane Oxygenation Support of a Neonate with Acute Respiratory Distress Syndrome after Cardiac Surgery

    PubMed Central

    Timpa, Joseph G.; O’Meara, Carlisle; McILwain, R. Britt; Dabal, Robert J.; Alten, Jeffrey A.

    2011-01-01

    Abstract: Extracorporeal membrane oxygenation (ECMO) is universally accepted as a potential lifesaving therapy for neonates suffering severe cardiorespiratory failure, with survival reported as 81% weaning off ECMO and 69% to hospital discharge in this population. Although ECMO may reduce mortality in certain neonatal patients, it is associated with significant complications. Air in the circuit complicates 4.9% of neonatal ECMO runs, and it is crucial that all ECMO caregivers are trained in the prevention of air embolism and possess the knowledge necessary to efficiently identify and remove air from the ECMO circuit to prevent life threatening consequences. We present a fatal case of neonatal systemic air embolism leading to massive entrainment of air into the ECMO venous return cannula of a neonatal patient with acute respiratory distress syndrome following repair of obstructed total anomalous pulmonary venous connection. We describe the pathophysiology and presentation of this rare condition and the importance of early recognition, due to its high mortality rate. PMID:21848179

  11. Venovenous extracorporeal membrane oxygenation for acute respiratory failure : A clinical review from an international group of experts.

    PubMed

    Fan, Eddy; Gattinoni, Luciano; Combes, Alain; Schmidt, Matthieu; Peek, Giles; Brodie, Dan; Muller, Thomas; Morelli, Andrea; Ranieri, V Marco; Pesenti, Antonio; Brochard, Laurent; Hodgson, Carol; Van Kiersbilck, Cecile; Roch, Antoine; Quintel, Michael; Papazian, Laurent

    2016-05-01

    Despite expensive life-sustaining interventions delivered in the ICU, mortality and morbidity in patients with acute respiratory failure (ARF) remain unacceptably high. Extracorporeal membrane oxygenation (ECMO) has emerged as a promising intervention that may provide more efficacious supportive care to these patients. Improvements in technology have made ECMO safer and easier to use, allowing for the potential of more widespread application in patients with ARF. A greater appreciation of the complications associated with the placement of an artificial airway and mechanical ventilation has led clinicians and researchers to seek viable alternatives to providing supportive care in these patients. Thus, this review will summarize the current knowledge regarding the use of venovenous (VV)-ECMO for ARF and describe some of the recent controversies in the field, such as mechanical ventilation, anticoagulation and transfusion therapy, and ethical concerns in patients supported with VV-ECMO. PMID:27007108

  12. Unconventional ratiometric-enhanced optical sensing of oxygen by mixed-phase TiO2

    NASA Astrophysics Data System (ADS)

    Lettieri, S.; Pallotti, D. K.; Gesuele, F.; Maddalena, P.

    2016-07-01

    We show that mixed-phase titanium dioxide (TiO2) can be effectively employed as an unconventional, inorganic, dual-emitting, and ratiometric optical sensor of O2. Simultaneous availability of rutile and anatase TiO2 photoluminescence (PL) and their peculiar "anti-correlated" PL responses to O2 allow using their ratio as a measurement parameter associated with the O2 concentration, leading to an experimental responsivity being by construction larger than the one obtainable for single-phase PL detection. A proof of this concept is given, showing a two-fold enhancement of the optical responsivity provided by the ratiometric approach. Besides the peculiar ratiometric-enhanced responsivity, other characteristics of mixed phase TiO2 can be envisaged as favorable for O2 optical probing, namely (a) low production costs, (b) absence of heterogeneous components, and (c) self-supporting properties. These characteristics encourage experimenting with its use for applications requiring high indicator quantities at a competitive price, possibly also tackling the need to develop supporting matrixes that carry the luminescent probes and avoiding issues related to the use of different components for ratiometric sensing.

  13. Omeprazole does not Potentiate Acute Oxygen Toxicity in Fetal Human Pulmonary Microvascular Endothelial Cells Exposed to Hyperoxia

    PubMed Central

    Patel, Ananddeep; Zhang, Shaojie; Moorthy, Bhagavatula; Shivanna, Binoy

    2015-01-01

    Hyperoxia contributes to the pathogenesis of broncho-pulmonary dysplasia (BPD), which is a developmental lung disease of premature infants that is characterized by an interruption of lung alveolar and pulmonary vascular development. Omeprazole (OM) is a proton pump inhibitor that is used to treat humans with gastric acid related disorders. Earlier we observed that OM-mediated aryl hydrocarbon receptor (AhR) activation attenuates acute hyperoxic lung injury in adult mice and oxygen toxicity in adult human lung cells. However, our later studies in newborn mice demonstrated that OM potentiates hyperoxia-induced developmental lung injury. Whether OM exerts a similar toxicity in primary human fetal lung cells is unknown. Hence, we tested the hypothesis that OM potentiates hyperoxia-induced cytotoxicity and ROS generation in the human fetal lung derived primary human pulmonary microvascular endothelial cells (HPMEC). OM activated AhR as evident by a dose-dependent increase in cytochrome P450 (CYP) 1A1 mRNA levels in OM-treated cells. Furthermore, OM at a concentration of 100 μM (OM 100) increased NADP(H) quinone oxidoreductase 1 (NQO1) expression. Surprisingly, hyperoxia decreased rather than increase the NQO1 protein levels in OM 100-treated cells. Exposure to hyperoxia increased cytotoxicity and hydrogen peroxide (H2O2) levels. Interestingly, OM 100-treated cells exposed to air had increased H2O2 levels. However, hyperoxia did not further augment H2O2 levels in OM 100-treated cells. Additionally, hyperoxia-mediated oxygen toxicity was similar in both vehicle- and OM-treated cells. These findings contradict our hypothesis and support the hypothesis that OM does not potentiate acute hyperoxic injury in HPMEC in vitro. PMID:26779382

  14. Oxygen sensing glucose biosensors based on alginate nano-micro systems

    NASA Astrophysics Data System (ADS)

    Chaudhari, Rashmi; Joshi, Abhijeet; Srivastava, Rohit

    2014-04-01

    Clinically glucose monitoring in diabetes management is done by point-measurement. However, an accurate, continuous glucose monitoring, and minimally invasive method is desirable. The research aims at developing fluorescence-mediated glucose detecting biosensors based on near-infrared radiation (NIR) oxygen sensitive dyes. Biosensors based on Glucose oxidase (GOx)-Rudpp loaded alginate microspheres (GRAM) and GOx-Platinum-octaethylporphyrin (PtOEP)-PLAalginate microsphere system (GPAM) were developed using air-driven atomization and characterized using optical microscopy, CLSM, fluorescence spectro-photometry etc. Biosensing studies were performed by exposing standard solutions of glucose. Uniform sized GRAM and GPAM with size 50+/-10μm were formed using atomization. CLSM imaging of biosensors suggests that Rudpp and PtOEP nanoparticles are uniformly distributed in alginate microspheres. The GRAM and GPAM showed a good regression constant of 0.974 and of 0.9648 over a range of 0-10 mM of glucose with a high sensitivity of 3.349%/mM (625 nm) and 2.38%/mM (645 nm) at 10 mM of glucose for GRAM and GPAM biosensor. GRAM and GPAM biosensors show great potential in development of an accurate and minimally invasive glucose biosensor. NIR dye based assays can aid sensitive, minimally-invasive and interference-free detection of glucose in diabetic patients.

  15. Arabidopsis CAP1-mediated ammonium sensing required reactive oxygen species in plant cell growth.

    PubMed

    Bai, Ling; Zhou, Yun; Ma, Xiaonan; Gao, Lijie; Song, Chun-Peng

    2014-06-18

    [Ca (2+)]cyt-associated protein kinase (CAP) gene 1 is a receptor-like kinase that belongs to CrRLK1L (Catharanthus roseus Receptor like kinase) subfamily. CAP1 has been identified as a novel modulator of NH 4(+) in the tonoplast, which regulates root hair growth by maintaining the cytoplasmic Ca (2+) gradients. Different expression pattern of tonoplast intrinsic protein (TIP2;3) in the CAP1 knock out mutant and wild type on Murashige and Skoog (MS) medium suggested that CAP1 influences transport activity to regulate the compartmentalization of NH 4(+) into vacuole. Lower expression level of Oxidative Signal-Inducible1(OXI1) in the cap1-1 root and the abnormal reactive oxygen species (ROS) gradient in root hair of cap1-1 on MS medium indicated that ROS signaling involve in CAP1-regulated root hair growth. Wild-type-like ROS distribution pattern in the cap1-1 root hair can be reestablished in seedlings grown on NH 4(+) deficient medium, which indicated that CAP1 functions as a sensor for NH 4(+) signaling in maintaining tip-focused ROS gradient in root hairs polar growth. PMID:24940875

  16. Defective Tibetan PHD2 Binding to p23 Links High Altitude Adaption to Altered Oxygen Sensing*

    PubMed Central

    Song, Daisheng; Li, Lin-sheng; Arsenault, Patrick R.; Tan, Qiulin; Bigham, Abigail W.; Heaton-Johnson, Katherine J.; Master, Stephen R.; Lee, Frank S.

    2014-01-01

    The Tibetan population has adapted to the chronic hypoxia of high altitude. Tibetans bear a genetic signature in the prolyl hydroxylase domain protein 2 (PHD2/EGLN1) gene, which encodes for the central oxygen sensor of the hypoxia-inducible factor (HIF) pathway. Recent studies have focused attention on two nonsynonymous coding region substitutions, D4E and C127S, both of which are markedly enriched in the Tibetan population. These amino acids reside in a region of PHD2 that harbors a zinc finger, which we have previously discovered binds to a Pro-Xaa-Leu-Glu (PXLE) motif in the HSP90 cochaperone p23, thereby recruiting PHD2 to the HSP90 pathway to facilitate HIF-α hydroxylation. We herein report that the Tibetan PHD2 haplotype (D4E/C127S) strikingly diminishes the interaction of PHD2 with p23, resulting in impaired PHD2 down-regulation of the HIF pathway. The defective binding to p23 depends on both the D4E and C127S substitutions. We also identify a PXLE motif in HSP90 itself that can mediate binding to PHD2 but find that this interaction is maintained with the D4E/C127S PHD2 haplotype. We propose that the Tibetan PHD2 variant is a loss of function (hypomorphic) allele, leading to augmented HIF activation to facilitate adaptation to high altitude. PMID:24711448

  17. Regulation of gene expression and secretory functions in oxygen-sensing pheochromocytoma cells.

    PubMed

    Conforti, L; Kobayashi, S; Beitner-Johnson, D; Conrad, P W; Freeman, T; Millhorn, D E

    1999-04-01

    The cellular response to hypoxia is complex. Specialized oxygen chemosensitive cells that are excitable respond to reduced O2 by membrane depolarization, altered gene expression, and neurotransmitter secretion. We have used the O2-sensitive pheochromocytoma (PC12) cell line to investigate the cellular response to hypoxia. Here, we present evidence that membrane depolarization and increased intracellular free Ca2+ are major regulatory events in these cells. Membrane depolarization is mediated by the inhibition of a slow-inactivating voltage-dependent potassium (K) channel. Evidence from molecular biology and patch-clamp studies indicate that the O2-sensitive K channel is a member of the Kv1 family. We also reviewed findings on the regulation of gene expression in PC12 cells during hypoxia. An increase in intracellular free Ca2+ is required for hypoxia-induced transcription of a number of genes including tyrosine hydroxylase (TH), the rate-limiting enzyme in the synthesis of catecholamine neurotransmitters, and several of the immediate early genes. We also reviewed the role of dopamine (DA) and adenosine (ADO) receptors in regulation of membrane depolarization and gene expression. PMID:10385038

  18. FIBER OPTICAL MICRO-DETECTORS FOR OXYGEN SENSING IN POWER PLANTS

    SciTech Connect

    Gregory L. Baker; Ruby N. Ghosh; D.J. Osborn III

    2004-04-01

    A reflection mode fiber optic oxygen sensor that can operate at high temperatures for power plant applications is being developed. The sensor is based on the {sup 3}O{sub 2} quenching of the red emission from hexanuclear molybdenum chloride clusters. The luminescence of Mo{sub 6}Cl{sub 12} immobilized in a sol-gel matrix was measured as a function of heater temperature up to 200 C, in an inert environment. While the luminescence decreased with temperature, the integrated intensity at 200 C should be sufficient to enable detection of the luminescence in a fiber geometry. Previously we found that aging Mo{sub 6}Cl{sub 12} at temperatures above 250 C converts the canary yellow Mo{sub 6}Cl{sub 12} to a non-luminescent gray solid. Optical and thermal aging experiments show that the alkali metal salts of Mo{sub 6}Cl{sub 12} have higher thermal stabilities and remain luminescent after aging at 280 C.

  19. Acute EPOC response in women to circuit training and treadmill exercise of matched oxygen consumption.

    PubMed

    Braun, W A; Hawthorne, W E; Markofski, M M

    2005-08-01

    The purpose of the study was to evaluate the effects of circuit training (CT) and treadmill exercise performed at matched rates of oxygen consumption and exercise duration on elevated post-exercise oxygen consumption (EPOC) in untrained women, while controlling for the menstrual cycle. Eight, untrained females (31.3 +/- 9.1 years; 2.04 +/- 0.26 l min(-1) estimated VO2max; BMI=24.6+/-3.9 kg/m2) volunteered to participate in the study. Testing was performed during the early follicular phase for each subject to minimize hormonal variability between tests. Subjects performed two exercise sessions approximately 28 days apart. Resting, supine energy expenditure was measured for 30 min preceding exercise and for 1 h after completion of exercise. Respiratory gas exchange data were collected continuously during rest and exercise periods via indirect calorimetry. CT consisted of three sets of eight common resistance exercises. Pre-exercise and exercise oxygen consumption was not different between testing days (P>0.05). Thus, exercise conditions were appropriately matched. Analysis of EPOC data revealed that CT resulted in a significantly higher (p<0.05) oxygen uptake during the first 30 min of recovery (0.27 +/- 0.01 l min(-1) vs 0.23+/-0.01 l min(-1)); though, at 60 min, treatment differences were not present. Mean VO2 remained significantly higher (0.231 +/- 0.01 l min(-1)) than pre-exercise measures (0.193 +/- 0.01 l min(-1)) throughout the 60-min EPOC period (p<0.05). Heart rate, RPE, V(E) and RER were all significantly greater during CT (p<0.05). When exercise VO2 and exercise duration were matched, CT was associated with a greater metabolic disturbance and cost during the early phases of EPOC. PMID:15942765

  20. Effects of acute hypoxia on the oxygen uptake kinetics of older adults during cycling exercise.

    PubMed

    Zerbini, Livio; Brighenti, Alfredo; Pellegrini, Barbara; Bortolan, Lorenzo; Antonetti, Tommaso; Schena, Federico

    2012-08-01

    Pulmonary oxygen uptake, heart rate (HR), and deoxyhemoglobin (HHb) kinetics were studied in a group of older adults exercising in hypoxic conditions. Fourteen healthy older adults (aged 66 ± 6 years) performed 4 exercise sessions that consisted of (i) an incremental test to exhaustion on a cycloergometer while breathing normoxic room air (fractional inspired oxygen (FiO(2)) = 20.9% O(2)); (ii) an incremental test to exhaustion on a cycloergometer while breathing hypoxic room air (FiO(2) = 15% O(2)); (iii) 3 repeated square wave cycling exercises at moderate intensity while breathing normoxic room air; and (iv) 3 repeated square wave cycling exercises at moderate intensity while breathing hypoxic room air. During all exercise sessions, pulmonary gas exchange was measured breath-by-breath; HHb was determined on the vastus lateralis muscle by near-infrared spectroscopy; and HR was collected beat-by-beat. The pulomary oxygen uptake kinetics became slower in hypoxia (31 ± 9 s) than in normoxia (27 ± 7 s) because of an increased mismatching between O(2) delivery to O(2) utilization at the level of the muscle. The HR and HHb kinetics did not change between hypoxia and normoxia. PMID:22680339

  1. Extracorporeal membrane oxygenation improves survival in a novel 24-hour pig model of severe acute respiratory distress syndrome.

    PubMed

    Araos, Joaquín; Alegría, Leyla; García, Patricio; Damiani, Felipe; Tapia, Pablo; Soto, Dagoberto; Salomon, Tatiana; Rodriguez, Felipe; Amthauer, Macarena; Erranz, Benjamín; Castro, Gabriel; Carreño, Pamela; Medina, Tania; Retamal, Jaime; Cruces, Pablo; Bugedo, Guillermo; Bruhn, Alejandro

    2016-01-01

    Extracorporeal membrane oxygenation (ECMO) is increasingly being used to treat severe acute respiratory distress syndrome (ARDS). However, there is limited clinical evidence about how to optimize the technique. Experimental research can provide an alternative to fill the actual knowledge gap. The purpose of the present study was to develop and validate an animal model of acute lung injury (ALI) which resembled severe ARDS, and which could be successfully supported with ECMO. Eighteen pigs were randomly allocated into three groups: sham, ALI, and ALI + ECMO. ALI was induced by a double-hit consisting in repeated saline lavage followed by a 2-hour period of injurious ventilation. All animals were followed up to 24 hours while being ventilated with conventional ventilation (tidal volume 10 ml/kg). The lung injury model resulted in severe hypoxemia, increased airway pressures, pulmonary hypertension, and altered alveolar membrane barrier function, as indicated by an increased protein concentration in bronchoalveolar fluid, and increased wet/dry lung weight ratio. Histologic examination revealed severe diffuse alveolar damage, characteristic of ARDS. Veno-venous ECMO was started at the end of lung injury induction with a flow > 60 ml/kg/min resulting in rapid reversal of hypoxemia and pulmonary hypertension. Mortality was 0, 66.6 and 16.6% in the SHAM, ALI and ALI + ECMO groups, respectively (p < 0.05). This is a novel clinically relevant animal model that can be used to optimize the approach to ECMO and foster translational research in extracorporeal lung support. PMID:27398166

  2. Extracorporeal membrane oxygenation improves survival in a novel 24-hour pig model of severe acute respiratory distress syndrome

    PubMed Central

    Araos, Joaquín; Alegría, Leyla; García, Patricio; Damiani, Felipe; Tapia, Pablo; Soto, Dagoberto; Salomon, Tatiana; Rodriguez, Felipe; Amthauer, Macarena; Erranz, Benjamín; Castro, Gabriel; Carreño, Pamela; Medina, Tania; Retamal, Jaime; Cruces, Pablo; Bugedo, Guillermo; Bruhn, Alejandro

    2016-01-01

    Extracorporeal membrane oxygenation (ECMO) is increasingly being used to treat severe acute respiratory distress syndrome (ARDS). However, there is limited clinical evidence about how to optimize the technique. Experimental research can provide an alternative to fill the actual knowledge gap. The purpose of the present study was to develop and validate an animal model of acute lung injury (ALI) which resembled severe ARDS, and which could be successfully supported with ECMO. Eighteen pigs were randomly allocated into three groups: sham, ALI, and ALI + ECMO. ALI was induced by a double-hit consisting in repeated saline lavage followed by a 2-hour period of injurious ventilation. All animals were followed up to 24 hours while being ventilated with conventional ventilation (tidal volume 10 ml/kg). The lung injury model resulted in severe hypoxemia, increased airway pressures, pulmonary hypertension, and altered alveolar membrane barrier function, as indicated by an increased protein concentration in bronchoalveolar fluid, and increased wet/dry lung weight ratio. Histologic examination revealed severe diffuse alveolar damage, characteristic of ARDS. Veno-venous ECMO was started at the end of lung injury induction with a flow > 60 ml/kg/min resulting in rapid reversal of hypoxemia and pulmonary hypertension. Mortality was 0, 66.6 and 16.6% in the SHAM, ALI and ALI + ECMO groups, respectively (p < 0.05). This is a novel clinically relevant animal model that can be used to optimize the approach to ECMO and foster translational research in extracorporeal lung support. PMID:27398166

  3. Acute Myocardial Infarction Complicated by Cardiogenic Shock: An Algorithm-Based Extracorporeal Membrane Oxygenation Program Can Improve Clinical Outcomes.

    PubMed

    Unai, Shinya; Tanaka, Daizo; Ruggiero, Nicholas; Hirose, Hitoshi; Cavarocchi, Nicholas C

    2016-03-01

    Extracorporeal membrane oxygenation (ECMO) in our institution resulted in near total mortality prior to the establishment of an algorithm-based program in July 2010. We hypothesized that an algorithm-based ECMO program improves the outcome of patients with acute myocardial infarction complicated with cardiogenic shock. Between March 2003 and July 2013, 29 patients underwent emergent catheterization for acute myocardial infarction due to left main or proximal left anterior descending artery occlusion complicated with cardiogenic shock (defined as systolic blood pressure <90 mm Hg despite multiple inotropes, with or without intra-aortic balloon pump, lactic acidosis). Of 29 patients, 15 patients were treated before July 2010 (Group 1, old program), and 14 patients were treated after July 2010 (Group 2, new program). There were no significant differences in the baseline characteristics, including age, sex, coronary risk factors, and left ventricular ejection fraction between the two groups. Cardiopulmonary resuscitation prior to ECMO was performed in two cases (13%) in Group 1 and four cases (29%) in Group 2. ECMO support was performed in one case (6.7%) in Group 1 and six cases (43%) in Group 2. The 30-day survival of Group 1 versus Group 2 was 40 versus 79% (P = 0.03), and 1-year survival rate was 20 versus 56% (P = 0.01). The survival rate for patients who underwent ECMO was 0% in Group 1 versus 83% in Group 2 (P = 0.09). In Group 2, the mean duration on ECMO was 9.8 ± 5.9 days. Of the six patients who required ECMO in Group 2, 100% were successfully weaned off ECMO or were bridged to ventricular assist device implantation. Initiation of an algorithm-based ECMO program improved the outcomes in patients with acute myocardial infarction complicated by cardiogenic shock. PMID:26148217

  4. Pyruvate modifies metabolic flux and nutrient sensing during extracorporeal membrane oxygenation in an immature swine model

    SciTech Connect

    Ledee, Dolena R.; Kajimoto, Masaki; O'Kelly-Priddy, Colleen M.; Olson, Aaron; Isern, Nancy G.; Robillard Frayne, Isabelle; Des Rosiers, Christine; Portman, Michael A.

    2015-07-01

    Extracorporeal membrane oxygenation (ECMO) provides mechanical circulatory support for infants and children with postoperative cardiopulmonary failure. Nutritional support is mandatory during ECMO, although specific actions for substrates on the heart have not been delineated. Prior work shows that enhancing pyruvate oxidation promotes successful weaning from ECMO. Accordingly, we closely examined the role of prolonged systemic pyruvate supplementation in modifying metabolic parameters during the unique conditions of ventricular unloading provided by ECMO. Twelve male mixed breed Yorkshire piglets (age 30-49 days) received systemic infusion of either normal saline (Group C) or pyruvate (Group P) during ECMO for 8 hours. Over the final hour piglets received [2-13C] pyruvate, and [13C6]-L-leucine, as an indicator for oxidation and protein synthesis. A significant increase in lactate and pyruvate concentrations occurred, along with an increase in the absolute concentration of all measured CAC intermediates. Group P showed greater anaplerotic flux through pyruvate carboxylation although pyruvate oxidation relative to citrate synthase flux was similar to Group C. The groups demonstrated similar leucine fractional contributions to acetyl-CoA and fractional protein synthesis rates. Pyruvate also promoted an increase in the phosphorylation state of several nutrient sensitive enzymes, such as AMPK and ACC, and promoted O-GlcNAcylation through the hexosamine biosynthetic pathway (HBP). In conclusion, prolonged pyruvate supplementation during ECMO modified anaplerotic pyruvate flux and elicited changes in important nutrient and energy sensitive pathways, while preserving protein synthesis. Therefore, the observed results support the further study of nutritional supplementation and its downstream effects on cardiac adaptation during ventricular unloading.

  5. Pyruvate modifies metabolic flux and nutrient sensing during extracorporeal membrane oxygenation in an immature swine model

    PubMed Central

    Ledee, Dolena R.; Kajimoto, Masaki; O'Kelly Priddy, Colleen M.; Olson, Aaron K.; Isern, Nancy; Robillard-Frayne, Isabelle; Des Rosiers, Christine

    2015-01-01

    Extracorporeal membrane oxygenation (ECMO) provides mechanical circulatory support for infants and children with postoperative cardiopulmonary failure. Nutritional support is mandatory during ECMO although specific actions for substrates on the heart have not been delineated. Prior work shows that enhancing pyruvate oxidation promotes successful weaning from ECMO. Accordingly, we tested the hypothesis that prolonged systemic pyruvate supplementation activates pyruvate oxidation in an immature swine model in vivo. Twelve male mixed-breed Yorkshire piglets (age 30–49 days) received systemic infusion of either normal saline (group C) or pyruvate (group P) during the final 6 h of 8 h of ECMO. Over the final hour, piglets received [2-13C] pyruvate, as a reference substrate for oxidation, and [13C6]-l-leucine, as an indicator for amino acid oxidation and protein synthesis. A significant increase in lactate and pyruvate concentrations occurred, along with an increase in the absolute concentration of the citric acid cycle intermediates. An increase in anaplerotic flux through pyruvate carboxylation in group P occurred compared with no change in pyruvate oxidation. Additionally, pyruvate promoted an increase in the phosphorylation state of several nutrient-sensitive enzymes, like AMP-activated protein kinase and acetyl CoA carboxylase, suggesting activation for fatty acid oxidation. Pyruvate also promoted O-GlcNAcylation through the hexosamine biosynthetic pathway. In conclusion, although prolonged pyruvate supplementation did not alter pyruvate oxidation, it did elicit changes in nutrient- and energy-sensitive pathways. Therefore, the observed results support the further study of pyruvate and its downstream effect on cardiac function. PMID:25910802

  6. Acute toxicity assessment of N,N-diethyl-m-toluamide (DEET) on the oxygen flux of the dinoflagellate Gymnodinium instriatum.

    PubMed

    Martinez, Eloy; Vélez, Sylvia M; Mayo, Marietta; Sastre, Miguel P

    2016-01-01

    Despite the ubiquitous occurrence of N,N-diethyl-m-toluamide (DEET) in aquatic systems, assessments evaluating the toxicity of DEET on phytoplankton species are summed to a single study on a unicellular green alga. In particular, the toxicological effects of DEET in dinoflagellates are unknown. In this study, we employed the mixotrophic dinoflagellate Gymnodinium instriatum as a study system to evaluate acute effects of DEET on the oxygen flux of laboratory cultures. This study reports an inhibitory reaction model of DEET described by the equation y = 4.99x(0.54), where y represents the percent inhibition of oxygen flux and x represents DEET concentration in mg L(−1) (r(2) = 0.98). Based on this model, the effective concentration of DEET needed to reduce O2 flux by 50% (EC50) for this species was found to be at 72.9 mg L(−1). The reported EC50 is more than five times lower than the EC50 reported previously for the unicellular green algae Chlorella protothecoides. This study raises the question of the potential toxicological effects of DEET in dinoflagellates, in particular those populations inhabiting systems characterized by low water circulation such as enclosed bays and lagoons. PMID:26467804

  7. Helmet CPAP versus Oxygen Therapy in Hypoxemic Acute Respiratory Failure: A Meta-Analysis of Randomized Controlled Trials

    PubMed Central

    Luo, Yuwen; Luo, Yan; Li, Yun; Zhou, Luqian; Zhu, Zhe; Chen, Yitai; Huang, Yuxia

    2016-01-01

    Purpose The efficacy of helmet continuous positive airway pressure (CPAP) in hypoxemic acute respiratory failure (hARF) remains unclear. The aim of this meta-analysis was to critically review studies that investigated the effect of helmet CPAP on gas exchange, mortality, and intubation rate in comparison with standard oxygen therapy. Materials and Methods We performed a meta-analysis of randomized controlled trials (RCTs) by searching the PubMed, Embase, Cochrane library, OVID, and CBM databases, and the bibliographies of the retrieved articles. Studies that enrolled adults with hARF who were treated with helmet CPAP and measured at least one of the following parameters were included: gas exchange, intubation rate, in-hospital mortality rate. Results Four studies with 377 subjects met the inclusion criteria and were analyzed. Compared to the standard oxygen therapy, helmet CPAP significantly increased the PaO2/FiO2 [weighted mean difference (WMD)=73.40, 95% confidence interval (95% CI): 43.92 to 102.87, p<0.00001], and decreased the arterial carbon dioxide levels (WMD=-1.92, 95% CI: -3.21 to -0.63, p=0.003), intubation rate [relative risk (RR)=0.21, 95% CI: 0.11 to 0.40, p<0.00001], and in-hospital mortality rate (RR=0.22, 95% CI: 0.09 to 0.50, p=0.0004). Conclusion The results of this meta-analysis suggest that helmet CPAP improves oxygenation and reduces mortality and intubation rates in hARF. However, the significant clinical and statistical heterogeneity of the literature implies that large RCTs are needed to determine the role of helmet CPAP in different hypoxemic ARF populations. PMID:27189288

  8. The Ratio of Partial Pressure Arterial Oxygen and Fraction of Inspired Oxygen 1 Day After Acute Respiratory Distress Syndrome Onset Can Predict the Outcomes of Involving Patients.

    PubMed

    Lai, Chih-Cheng; Sung, Mei-I; Liu, Hsiao-Hua; Chen, Chin-Ming; Chiang, Shyh-Ren; Liu, Wei-Lun; Chao, Chien-Ming; Ho, Chung-Han; Weng, Shih-Feng; Hsing, Shu-Chen; Cheng, Kuo-Chen

    2016-04-01

    The initial hypoxemic level of acute respiratory distress syndrome (ARDS) defined according to Berlin definition might not be the optimal predictor for prognosis. We aimed to determine the predictive validity of the stabilized ratio of partial pressure arterial oxygen and fraction of inspired oxygen (PaO2/FiO2 ratio) following standard ventilator setting in the prognosis of patients with ARDS.This prospective observational study was conducted in a single tertiary medical center in Taiwan and compared the stabilized PaO2/FiO2 ratio (Day 1) following standard ventilator settings and the PaO2/FiO2 ratio on the day patients met ARDS Berlin criteria (Day 0). Patients admitted to intensive care units and in accordance with the Berlin criteria for ARDS were collected between December 1, 2012 and May 31, 2015. Main outcome was 28-day mortality. Arterial blood gas and ventilator setting on Days 0 and 1 were obtained.A total of 238 patients met the Berlin criteria for ARDS were enrolled, and they were classified as mild (n = 50), moderate (n = 125), and severe (n = 63) ARDS, respectively. Twelve (5%) patients who originally were classified as ARDS did not continually meet the Berlin definition, and a total of 134 (56%) patients had the changes regarding the severity of ARDS from Day 0 to Day 1. The 28-day mortality rate was 49.1%, and multivariate analysis identified age, PaO2/FiO2 on Day 1, number of organ failures, and positive fluid balance within 5 days as significant risk factors of death. Moreover, the area under receiver-operating curve for mortality prediction using PaO2/FiO2 on Day 1 was significant higher than that on Day 0 (P = 0.016).PaO2/FiO2 ratio on Day 1 after applying mechanical ventilator is a better predictor of outcomes in patients with ARDS than those on Day 0. PMID:27057912

  9. Heteronuclear Ir(III)-Ln(III) Luminescent Complexes: Small-Molecule Probes for Dual Modal Imaging and Oxygen Sensing.

    PubMed

    Jana, Atanu; Crowston, Bethany J; Shewring, Jonathan R; McKenzie, Luke K; Bryant, Helen E; Botchway, Stanley W; Ward, Andrew D; Amoroso, Angelo J; Baggaley, Elizabeth; Ward, Michael D

    2016-06-01

    Luminescent, mixed metal d-f complexes have the potential to be used for dual (magnetic resonance imaging (MRI) and luminescence) in vivo imaging. Here, we present dinuclear and trinuclear d-f complexes, comprising a rigid framework linking a luminescent Ir center to one (Ir·Ln) or two (Ir·Ln2) lanthanide metal centers (where Ln = Eu(III) and Gd(III), respectively). A range of physical, spectroscopic, and imaging-based properties including relaxivity arising from the Gd(III) units and the occurrence of Ir(III) → Eu(III) photoinduced energy-transfer are presented. The rigidity imposed by the ligand facilitates high relaxivities for the Gd(III) complexes, while the luminescence from the Ir(III) and Eu(III) centers provide luminescence imaging capabilities. Dinuclear (Ir·Ln) complexes performed best in cellular studies, exhibiting good solubility in aqueous solutions, low toxicity after 4 and 18 h, respectively, and punctate lysosomal staining. We also demonstrate the first example of oxygen sensing in fixed cells using the dyad Ir·Gd, via two-photon phosphorescence lifetime imaging (PLIM). PMID:27219675

  10. Impairment of Venous Drainage on Extracorporeal Membrane Oxygenation Secondary to Air Trapping in Acute Asphyxial Asthma.

    PubMed

    Niimi, Kevin S; Lewis, Leslie S; Fanning, Jeffrey J

    2015-06-01

    The inability to adequately support a patient on extracorporeal membrane oxygenation (ECMO) due to impaired drainage is not an uncommon occurrence during support. Typically, the causes include hypovolemia, kinks in the circuit, cannula malposition, or inadequate cannula size. In this report we present an uncommon etiology of this problem. A 3-year-old female presented to our hospital in status asthmaticus and pulseless electrical activity (PEA). This was a result of dynamic hyperinflation of the lungs causing physical obstruction of venous return to the heart. Upon initiating venoarterial (VA) ECMO, we experienced inadequate drainage that did not improve despite multiple interventions. This resolved with the addition of an inhaled anesthetic gas to treat this patient's severe bronchospasm. This case illustrates the importance of considering a patient's physiology or disease state and how that may affect the mechanics of ECMO support. PMID:26405359

  11. Vorinostat Induces Reactive Oxygen Species and DNA Damage in Acute Myeloid Leukemia Cells

    PubMed Central

    Pettersson, Filippa; Retrouvey, Hélène; Skoulikas, Sophia; Miller, Wilson H.

    2011-01-01

    Histone deacetylase inhibitors (HDACi) are promising anti-cancer agents, however, their mechanisms of action remain unclear. In acute myeloid leukemia (AML) cells, HDACi have been reported to arrest growth and induce apoptosis. In this study, we elucidate details of the DNA damage induced by the HDACi vorinostat in AML cells. At clinically relevant concentrations, vorinostat induces double-strand breaks and oxidative DNA damage in AML cell lines. Additionally, AML patient blasts treated with vorinostat display increased DNA damage, followed by an increase in caspase-3/7 activity and a reduction in cell viability. Vorinostat-induced DNA damage is followed by a G2-M arrest and eventually apoptosis. We found that pre-treatment with the antioxidant N-acetyl cysteine (NAC) reduces vorinostat-induced DNA double strand breaks, G2-M arrest and apoptosis. These data implicate DNA damage as an important mechanism in vorinostat-induced growth arrest and apoptosis in both AML cell lines and patient-derived blasts. This supports the continued study and development of vorinostat in AMLs that may be sensitive to DNA-damaging agents and as a combination therapy with ionizing radiation and/or other DNA damaging agents. PMID:21695163

  12. Acute effects of sustained isometric knee extension on cerebral and muscle oxygenation responses.

    PubMed

    Pereira, Marta Inez R; Gomes, Paulo Sergio C; Bhambhani, Yagesh N

    2009-07-01

    Cerebral contra-lateral frontal lobe and the dominant vastus lateralis muscle oxygenation (Cox, Mox) and blood volume (Cbv, Mbv) were recorded simultaneously using near infrared spectroscopy (NIRS) in 12 healthy volunteers (37.4 +/- 9.9 years; 72.3 +/- 16.1 kg; 171.0 +/- 9.6 cm) during 2 min resting baseline, an isometric knee extension with the 1 RM load sustained to the point of fatigue, and 3 min recovery. The mean exercise duration was 19.1 +/- 2.6 s. During the contraction, Cox and Cbv increased systematically with no sign of levelling off until the point of fatigue. In contrast, Mox and Mbv declined continuously until the termination of exercise. Qualitative analysis of these NIRS profiles suggested that maximal isometric performance under normoxic conditions was most likely not limited by central neuronal activation, but rather, was due to factors within the exercising muscle. It is likely that depletion of intramuscular stores of high energy phosphates and oxymyoglobin, as well as the accumulation of metabolites from anaerobic pathways, were implicated in fatigue during this sustained high intensity isometric contraction. PMID:19486342

  13. Outcome of veno-venous extracorporeal membrane oxygenation use in acute respiratory distress syndrome after cardiac surgery with cardiopulmonary bypass

    PubMed Central

    Song, Joo Han; Woo, Won Ki; Song, Seung Hwan; Kim, Hyo Hyun; Kim, Bong Joon; Kim, Ha Eun; Kim, Do Jung; Suh, Jee Won; Shin, Yu Rim; Park, Han Ki; Lee, Seung Hyun; Joo, Hyun Chel; Lee, Sak; Chang, Byung Chul; Yoo, Kyung Jong; Kim, Young Sam

    2016-01-01

    Background Cardiac surgery with cardiopulmonary bypass (CPB) is a known risk factor for acute respiratory distress syndrome (ARDS). We aimed to analyze the treatment outcome in patients who required veno-venous extracorporeal membrane oxygenation (VV-ECMO) for postcardiotomy ARDS despite other rescue modalities. Methods We retrospectively reviewed the outcomes in 13 patients (mean age, 54.7±5.9 years) who received VV-ECMO support for refractory ARDS after cardiac surgery between March 2013 and February 2016 at Severance Hospital, Yonsei University (Seoul, Korea). Results At the start of VV-ECMO, the average lung injury score was 3.0±0.2, and the Respiratory Extracorporeal Membrane Oxygenation Survival Prediction (RESP) score was −4±1.1. Although 7 patients initiated VV-ECMO support within 24 h from operation, the remaining 6 started at a median of 8.5 days (range, 5−16 days). Nine (69.3%) patients were successfully weaned from VV-ECMO. After a median follow-up duration of 14.5 months (range, 1.0−33.0 months) for survivors, the 1-year overall survival was 58.6%±14.4%. The differences in the overall survival from VV-ECMO according to the RESP score risk classes were borderline significant (100% in class III, 50%±25% in class IV, and 20%±17.9% in class V; P=0.088). Conclusions VV-ECMO support can be a feasible rescue strategy for adult patients who develop refractory ARDS after a cardiac surgery. Additionally, the RESP score seems a valuable prognostic tool for post-ECMO survival outcome in this patient population as well. PMID:27499972

  14. The acute effects of nicotine, tobacco smoke and carbon monoxide on myocardial oxygen tension in the anaesthetized cat

    PubMed Central

    Rink, Richard D.

    1978-01-01

    1 The acute effects of nicotine, tobacco smoke, and carbon monoxide on myocardial oxygen tension (MPo2) were estimated amperometrically in 33 anaesthetized open-chest cats with a glass-insulated 25 μm platinum cathode within a 22-gauge needle implanted in the left ventricular wall. 2 MPo2 was 1.6-60 mmHg (mean 23.5 mmHg) when arterial Po2 was >80 mmHg. Sequential intravenous infusions of nicotine (2-3 μg/kg every 45 s) or intracheal puffs (3-5 ml) of tobacco smoke commonly produced transitory increases (25-35 mmHg) of arterial pressure and 4-6 mmHg increments of MPo2. Intratracheal puffs (5 ml) of 5% carbon monoxide sufficient to increase carboxyhaemoglobin from 0.8 to 1.5% to 4-7% had no effect on arterial Po2 or blood pressure but typically decreased MPo2 by approximately 1-4 mmHg. Augmentation of MPo2 often succeeded carbon monoxide administration. 3 Arterial hypoxia (arterial Po2 < 60 mmHg) reduced mean MPo2 to 14.4 mmHg but anoxic levels were not observed. Pressor responses to nicotine and tobacco smoke were accompanied by small increases (usually 1-3 mmHg) of MPo2. Puffs of 5% carbon monoxide had less effect than during normoxia. Locations of low MPo2 (<10 mmHg) were unaffected as carboxyhaemoglobin was raised to 7-11% during hypoxaemia. 4 It is concluded that nicotine and tobacco smoke cause augmentation of myocardial oxygen supply, even during moderate hypoxaemia. By contrast, smoking dosages of carbon monoxide have the potential of producing a small reduction of MPo2 during normoxia, but the effect is negligible during moderate hypoxaemia. PMID:656704

  15. Cognitive functions and cerebral oxygenation changes during acute and prolonged hypoxic exposure.

    PubMed

    Davranche, Karen; Casini, Laurence; Arnal, Pierrick J; Rupp, Thomas; Perrey, Stéphane; Verges, Samuel

    2016-10-01

    The present study aimed to assess specific cognitive processes (cognitive control and time perception) and hemodynamic correlates using functional near-infrared spectroscopy (fNIRS) during acute and prolonged high-altitude exposure. Eleven male subjects were transported via helicopter and dropped at 14 272 ft (4 350 meters) of altitude where they stayed for 4 days. Cognitive tasks, involving a conflict task and temporal bisection task, were performed at sea level the week before ascending to high altitude, the day of arrival (D0), the second (D2) and fourth (D4) day at high altitude. Cortical hemodynamic changes in the prefrontal cortex (PFC) area were monitored with fNIRS at rest and during the conflict task. Results showed that high altitude impacts information processing in terms of speed and accuracy. In the early hours of exposure (D0), participants displayed slower reaction times (RT) and decision errors were twice as high. While error rate for simple spontaneous responses remained twice that at sea level, the slow-down of RT was not detectable after 2 days at high-altitude. The larger fNIRS responses from D0 to D2 suggest that higher prefrontal activity partially counteracted cognitive performance decrements. Cognitive control, assessed through the build-up of a top-down response suppression mechanism, the early automatic response activation and the post-error adjustment were not impacted by hypoxia. However, during prolonged hypoxic exposure the temporal judgments were underestimated suggesting a slowdown of the internal clock. A decrease in cortical arousal level induced by hypoxia could consistently explain both the slowdown of the internal clock and the persistence of a higher number of errors after several days of exposure. PMID:27262217

  16. Extracorporeal Membrane Oxygenation as Bridge-to-Decision in Acute Heart Failure due to Systemic Light-Chain Amyloidosis

    PubMed Central

    Silva, Jennifer Mancio; Fontes-Carvalho, Ricardo; Valente, Dília; Almeida, Cristiana; Cruz, António José; Tente, David; Coelho, Henrique; Oliveira, Marco; Albuquerque, Aníbal; Ribeiro, Vasco Gama

    2015-01-01

    Patient: Female, 58 Final Diagnosis: Acute hear failure Symptoms: Dispnoea • edema • fatigue Medication: — Clinical Procedure: Bone marrow biopsy • endomyocardial biopsy • abdominal subcutaneous fat biopsy under ECMO support Specialty: Cardiology Objective: Rare disease Background: Cardiac amyloidosis results from the amyloid deposition in heart tissue, either in the context of a systemic disease or as a localized form. Several pro-amyloid proteins can produce amyloid deposits in the heart. Each of these amyloidoses has characteristic clinical (cardiac and extracardiac) features, and a specific diagnosis and treatment. Case Report: A 58-year-old woman who presented with acute heart failure and echocardiographic findings strongly suggestive of infiltrative cardiomyopathy needed percutaneous veno-arterial extracorporeal membrane oxygenation (ECMO) as bridge-to-decision. Amyloid deposition was found on endomyocardial and bone marrow biopsies. Bone marrow plasma cell infiltrate with acute renal lesion and hypercalcemia confirmed the diagnosis of multiple myeloma-associated systemic light-chain amyloidosis (AL). Refractory shock with multi-organic failure syndrome persisted and no improvements in left ventricular function and structure were seen. After extensive discussion by a multidisciplinary team, and with the patients’ family, she was not considered eligible for high-dose chemotherapy and/or autologous stem cell transplantation, heart transplantation, or sequential heart with autologous stem cell transplantation. The patient died a few hours after ECMO withdrawal. During the 14 days of ECMO support no major bleeding or thrombotic complications occurred. Conclusions: The clinician must consider a diagnosis of cardiac amyloidosis in patients with heart failure, a restrictive type of cardiomyopathy with ventricular hypertrophy in the absence of valve abnormalities, or uncontrolled arterial hypertension. Although developments in chemotherapy have greatly

  17. High-sensitivity extended-gate field-effect transistors as pH sensors with oxygen-modified reduced graphene oxide films coated on different reverse-pyramid silicon structures as sensing heads

    NASA Astrophysics Data System (ADS)

    Li, Yu-Ren; Chang, Shih-hsueh; Chang, Chia-Tsung; Tsai, Wan-Lin; Chiu, Yu-Kai; Yang, Po-Yu; Cheng, Huang-Chung

    2016-04-01

    A high-performance extended-gate field-effect transistor (EGFET) as pH sensor with its microstructured sensing head composed of an oxygen-modified reduced graphene oxide film (RGOF) on a reverse-pyramid (RP) Si structure was developed to achieve a high sensitivity of 57.5 mV/pH with an excellent linearity of 0.9929 in a wide pH sensing range of 1-13. These features were ascribed to the large amount of sensing sites and large sensing area. In contrast, the planar Si substrate with the oxygen-plasma-treated RGOF (OPT-RGOF) at the optimal bias power showed a sensitivity of 52.9 mV/pH compared with 45.0 mV/pH for that without plasma treatment. It reveals that oxygen plasma can produce oxygen-containing groups as sensing sites, enhancing proton sensing characteristics. However, oxygen plasma treatment at high bias powers would cause damage to the RGOFs, resulting in poor conducting and sensing properties. On the other hand, the use of the RP structures could increase the effective sensing area and further promote the sensing performance.

  18. The SOS Pilot Study: A RCT of Routine Oxygen Supplementation Early after Acute Stroke—Effect on Recovery of Neurological Function at One Week

    PubMed Central

    Roffe, Christine; Ali, Khalid; Warusevitane, Anushka; Sills, Sheila; Pountain, Sarah; Allen, Martin; Hodsoll, John; Lally, Frank; Jones, Peter; Crome, Peter

    2011-01-01

    Mild hypoxia is common after stroke and associated with poor long-term outcome. Oxygen supplementation could prevent hypoxia and improve recovery. A previous study of routine oxygen supplementation showed no significant benefit at 7 and 12 months. This pilot study reports the effects of routine oxygen supplementation for 72 hours on oxygen saturation and neurological outcomes at 1 week after a stroke. Methods Patients with a clinical diagnosis of acute stroke were recruited within 24 h of hospital admission between October 2004 and April 2008. Participants were randomized to oxygen via nasal cannulae (72 h) or control (room air, oxygen given only if clinically indicated). Clinical outcomes were assessed by research team members at 1 week. Baseline data for oxygen (n = 148) and control (n = 141) did not differ between groups. Results The median (interquartile range) National Institutes of Health Stroke Scale (NIHSS) score for the groups at baseline was 6 (7) and 5 (7) respectively. The median Nocturnal Oxygen Saturation during treatment was 1.4% (0.3) higher in the oxygen than in the control group (p<0.001) during the intervention. At 1 week, the median NIHSS score had reduced by 2 (3) in the oxygen and by 1 (2) in the control group. 31% of participants in the oxygen group and 14% in the control group had an improvement of ≥4 NIHSS points at 1 week doubling the odds of improvement in the oxygen group (OR: 2.9). Conclusion Our data show that routine oxygen supplementation started within 24 hours of hospital admission with acute stroke led to a small, but statistically significant, improvement in neurological recovery at 1 week. However, the difference in NIHSS improvement may be due to baseline imbalance in stroke severity between the two groups and needs to be confirmed in a larger study and linked to longer-term clinical outcome. Trial Registration Controlled-Trials.com ISRCTN12362720; European Clinical Trials Database 2004-001866-41 PMID:21625533

  19. Acute supplementation of N-acetylcysteine does not affect muscle blood flow and oxygenation characteristics during handgrip exercise.

    PubMed

    Smith, Joshua R; Broxterman, Ryan M; Ade, Carl J; Evans, Kara K; Kurti, Stephanie P; Hammer, Shane M; Barstow, Thomas J; Harms, Craig A

    2016-04-01

    N-acetylcysteine (NAC; antioxidant and thiol donor) supplementation has improved exercise performance and delayed fatigue, but the underlying mechanisms are unknown. One possibility isNACsupplementation increases limb blood flow during severe-intensity exercise. The purpose was to determine ifNACsupplementation affected exercising arm blood flow and muscle oxygenation characteristics. We hypothesized thatNACwould lead to higher limb blood flow and lower muscle deoxygenation characteristics during severe-intensity exercise. Eight healthy nonendurance trained men (21.8 ± 1.2 years) were recruited and completed two constant power handgrip exercise tests at 80% peak power until exhaustion. Subjects orally consumed either placebo (PLA) orNAC(70 mg/kg) 60 min prior to handgrip exercise. Immediately prior to exercise, venous blood samples were collected for determination of plasma redox balance. Brachial artery blood flow (BABF) was measured via Doppler ultrasound and flexor digitorum superficialis oxygenation characteristics were measured via near-infrared spectroscopy. FollowingNACsupplementaiton, plasma cysteine (NAC: 47.2 ± 20.3 μmol/L vs.PLA: 9.6 ± 1.2 μmol/L;P = 0.001) and total cysteine (NAC: 156.2 ± 33.9 μmol/L vs.PLA: 132.2 ± 16.3 μmol/L;P = 0.048) increased. Time to exhaustion was not significantly different (P = 0.55) betweenNAC(473.0 ± 62.1 sec) andPLA(438.7 ± 58.1 sec). RestingBABFwas not different (P = 0.79) withNAC(99.3 ± 31.1 mL/min) andPLA(108.3 ± 46.0 mL/min).BABFwas not different (P = 0.42) during exercise or at end-exercise (NAC: 413 ± 109 mL/min;PLA: 445 ± 147 mL/min). Deoxy-[hemoglobin+myoglobin] and total-[hemoglobin+myoglobin] were not significantly different (P = 0.73 andP = 0.54, respectively) at rest or during exercise between conditions. We conclude that acuteNACsupplementation does not alter oxygen delivery during exercise in men. PMID:27044854

  20. TRPV4 inhibition counteracts edema and inflammation and improves pulmonary function and oxygen saturation in chemically induced acute lung injury

    PubMed Central

    Balakrishna, Shrilatha; Song, Weifeng; Achanta, Satyanarayana; Doran, Stephen F.; Liu, Boyi; Kaelberer, Melanie M.; Yu, Zhihong; Sui, Aiwei; Cheung, Mui; Leishman, Emma; Eidam, Hilary S.; Ye, Guosen; Willette, Robert N.; Thorneloe, Kevin S.; Bradshaw, Heather B.; Matalon, Sadis

    2014-01-01

    The treatment of acute lung injury caused by exposure to reactive chemicals remains challenging because of the lack of mechanism-based therapeutic approaches. Recent studies have shown that transient receptor potential vanilloid 4 (TRPV4), an ion channel expressed in pulmonary tissues, is a crucial mediator of pressure-induced damage associated with ventilator-induced lung injury, heart failure, and infarction. Here, we examined the effects of two novel TRPV4 inhibitors in mice exposed to hydrochloric acid, mimicking acid exposure and acid aspiration injury, and to chlorine gas, a severe chemical threat with frequent exposures in domestic and occupational environments and in transportation accidents. Postexposure treatment with a TRPV4 inhibitor suppressed acid-induced pulmonary inflammation by diminishing neutrophils, macrophages, and associated chemokines and cytokines, while improving tissue pathology. These effects were recapitulated in TRPV4-deficient mice. TRPV4 inhibitors had similar anti-inflammatory effects in chlorine-exposed mice and inhibited vascular leakage, airway hyperreactivity, and increase in elastance, while improving blood oxygen saturation. In both models of lung injury we detected increased concentrations of N-acylamides, a class of endogenous TRP channel agonists. Taken together, we demonstrate that TRPV4 inhibitors are potent and efficacious countermeasures against severe chemical exposures, acting against exaggerated inflammatory responses, and protecting tissue barriers and cardiovascular function. PMID:24838754

  1. TRPV4 inhibition counteracts edema and inflammation and improves pulmonary function and oxygen saturation in chemically induced acute lung injury.

    PubMed

    Balakrishna, Shrilatha; Song, Weifeng; Achanta, Satyanarayana; Doran, Stephen F; Liu, Boyi; Kaelberer, Melanie M; Yu, Zhihong; Sui, Aiwei; Cheung, Mui; Leishman, Emma; Eidam, Hilary S; Ye, Guosen; Willette, Robert N; Thorneloe, Kevin S; Bradshaw, Heather B; Matalon, Sadis; Jordt, Sven-Eric

    2014-07-15

    The treatment of acute lung injury caused by exposure to reactive chemicals remains challenging because of the lack of mechanism-based therapeutic approaches. Recent studies have shown that transient receptor potential vanilloid 4 (TRPV4), an ion channel expressed in pulmonary tissues, is a crucial mediator of pressure-induced damage associated with ventilator-induced lung injury, heart failure, and infarction. Here, we examined the effects of two novel TRPV4 inhibitors in mice exposed to hydrochloric acid, mimicking acid exposure and acid aspiration injury, and to chlorine gas, a severe chemical threat with frequent exposures in domestic and occupational environments and in transportation accidents. Postexposure treatment with a TRPV4 inhibitor suppressed acid-induced pulmonary inflammation by diminishing neutrophils, macrophages, and associated chemokines and cytokines, while improving tissue pathology. These effects were recapitulated in TRPV4-deficient mice. TRPV4 inhibitors had similar anti-inflammatory effects in chlorine-exposed mice and inhibited vascular leakage, airway hyperreactivity, and increase in elastance, while improving blood oxygen saturation. In both models of lung injury we detected increased concentrations of N-acylamides, a class of endogenous TRP channel agonists. Taken together, we demonstrate that TRPV4 inhibitors are potent and efficacious countermeasures against severe chemical exposures, acting against exaggerated inflammatory responses, and protecting tissue barriers and cardiovascular function. PMID:24838754

  2. Clinical utility of high-flow nasal cannula oxygen therapy for acute respiratory failure in patients with hematological disease.

    PubMed

    Harada, Kaito; Kurosawa, Shuhei; Hino, Yutaro; Yamamoto, Keita; Sakaguchi, Masahiro; Ikegawa, Shuntaro; Hattori, Keiichro; Igarashi, Aiko; Watakabe, Kyoko; Senoo, Yasushi; Najima, Yuho; Hagino, Takeshi; Doki, Noriko; Kobayashi, Takeshi; Kakihana, Kazuhiko; Iino, Toshihiro; Sakamaki, Hisashi; Ohashi, Kazuteru

    2016-01-01

    A high-flow nasal cannula (HFNC) is a newly developed device that enables high-flow oxygen therapy for patients with serious cardiopulmonary problems, but there are few data regarding its use in patients with hematological disease. The efficacy and tolerability of HFNCs for patients who developed ARF during the treatment of various hematological diseases was evaluated. Fifty-six patients underwent HFNC therapy during the last 2 years, and the causes of ARF were mainly pneumonia (n = 37) or acute congestive heart failure (n = 7). Only 11 patients (20 %) showed a good response to HFNC therapy, and remaining 45 patients (80 %) failed to respond to the initial HFNC therapy and, therefore, underwent second-line therapy including endotracheal intubation with mechanical ventilation (n = 15), non-invasive positive pressure ventilation (n = 1), or narcotic palliation alone (n = 29). Thus, HFNC appear not to be a viable treatment option in 4 out of 5 patients in this cohort of patients with hematological disease, but it was well tolerated in most patients (96 %); no major complications except for nasal soreness (n = 2) were observed. Multivariate analysis showed that the cause of ARF (pneumonia, odds ratio 11.2, 95 % CI 1.76-71.5, p = 0.01) was the only risk factor for treatment failure. PMID:27186476

  3. Monochloramine-sensitive amperometric microelectrode: optimization of gold, platinum, and carbon fiber sensing materials for removal of dissolved oxygen interference

    EPA Science Inventory

    Amperometric monochloramine detection using newly fabricated gold, platinum, and carbon-fiber microsensors was investigated to optimize sensor operation and eliminate oxygen interference. Gold and platinum microsensors exhibited no oxygen interference during monochloramine measu...

  4. Protective Role of Proton-Sensing TDAG8 in Lipopolysaccharide-Induced Acute Lung Injury

    PubMed Central

    Tsurumaki, Hiroaki; Mogi, Chihiro; Aoki-Saito, Haruka; Tobo, Masayuki; Kamide, Yosuke; Yatomi, Masakiyo; Sato, Koichi; Dobashi, Kunio; Ishizuka, Tamotsu; Hisada, Takeshi; Yamada, Masanobu; Okajima, Fumikazu

    2015-01-01

    Acute lung injury is characterized by the infiltration of neutrophils into lungs and the subsequent impairment of lung function. Here we explored the role of TDAG8 in lung injury induced by lipopolysaccharide (LPS) administrated intratracheally. In this model, cytokines and chemokines released from resident macrophages are shown to cause neutrophilic inflammation in the lungs. We found that LPS treatment increased TDAG8 expression in the lungs and confirmed its expression in resident macrophages in bronchoalveolar lavage (BAL) fluids. LPS administration remarkably increased neutrophil accumulation without appreciable change in the resident macrophages, which was associated with increased penetration of blood proteins into BAL fluids, interstitial accumulation of inflammatory cells, and damage of the alveolar architecture. The LPS-induced neutrophil accumulation and the associated lung damage were enhanced in TDAG8-deficient mice as compared with those in wild-type mice. LPS also increased several mRNA and protein expressions of inflammatory cytokines and chemokines in the lungs or BAL fluids. Among these inflammatory mediators, mRNA and protein expression of KC (also known as CXCL1), a chemokine of neutrophils, were significantly enhanced by TDAG8 deficiency. We conclude that TDAG8 is a negative regulator for lung neutrophilic inflammation and injury, in part, through the inhibition of chemokine production. PMID:26690120

  5. Oxygen sensing in yeast: Evidence for the involvement of the respiratory chain in regulating the transcription of a subset of hypoxic genes

    PubMed Central

    Kwast, Kurt E.; Burke, Patricia V.; Staahl, Brett T.; Poyton, Robert O.

    1999-01-01

    Oxygen availability affects the transcription of a number of genes in nearly all organisms. Although the molecular mechanisms for sensing oxygen are not precisely known, heme is thought to play a pivotal role. Here, we address the possibility that oxygen sensing in yeast, as in mammals, involves a redox-sensitive hemoprotein. We have found that carbon monoxide (CO) completely blocks the anoxia-induced expression of two hypoxic genes, OLE1 and CYC7, partially blocks the induction of a third gene, COX5b, and has no effect on the expression of other hypoxic or aerobic genes. In addition, transition metals (Co and Ni) induce the expression of OLE1 and CYC7 in a concentration-dependent manner under aerobic conditions. These findings suggest that the redox state of an oxygen-binding hemoprotein is involved in controlling the expression of at least two hypoxic yeast genes. By using mutants deficient in each of the two major yeast CO-binding hemoproteins (cytochrome c oxidase and flavohemoglobin), respiratory inhibitors, and cob1 and ρ0 mutants, we have found that the respiratory chain is involved in the anoxic induction of these two genes and that cytochrome c oxidase is likely the hemoprotein “sensor.” Our findings also indicate that there are at least two classes of hypoxic genes in yeast (CO sensitive and CO insensitive) and imply that multiple pathways/mechanisms are involved in modulating the expression of hypoxic yeast genes. PMID:10318903

  6. Oxygen Sensing via the Ethylene Response Transcription Factor RAP2.12 Affects Plant Metabolism and Performance under Both Normoxia and Hypoxia.

    PubMed

    Paul, Melanie Verena; Iyer, Srignanakshi; Amerhauser, Carmen; Lehmann, Martin; van Dongen, Joost T; Geigenberger, Peter

    2016-09-01

    Subgroup-VII-ethylene-response-factor (ERF-VII) transcription factors are involved in the regulation of hypoxic gene expression and regulated by proteasome-mediated proteolysis via the oxygen-dependent branch of the N-end-rule pathway. While research into ERF-VII mainly focused on their role to regulate anoxic gene expression, little is known on the impact of this oxygen-sensing system in regulating plant metabolism and growth. By comparing Arabidopsis (Arabidopsis thaliana) plants overexpressing N-end-rule-sensitive and insensitive forms of the ERF-VII-factor RAP2.12, we provide evidence that oxygen-dependent RAP2.12 stability regulates central metabolic processes to sustain growth, development, and anoxic resistance of plants. (1) Under normoxia, overexpression of N-end-rule-insensitive Δ13RAP2.12 led to increased activities of fermentative enzymes and increased accumulation of fermentation products, which were accompanied by decreased adenylate energy states and starch levels, and impaired plant growth and development, indicating a role of oxygen-regulated RAP2.12 degradation to prevent aerobic fermentation. (2) In Δ13RAP2.12-overexpressing plants, decreased carbohydrate reserves also led to a decrease in anoxic resistance, which was prevented by external Suc supply. (3) Overexpression of Δ13RAP2.12 led to decreased respiration rates, changes in the levels of tricarboxylic acid cycle intermediates, and accumulation of a large number of amino acids, including Ala and γ-amino butyric acid, indicating a role of oxygen-regulated RAP2.12 abundance in controlling the flux-modus of the tricarboxylic acid cycle. (4) The increase in amino acids was accompanied by increased levels of immune-regulatory metabolites. These results show that oxygen-sensing, mediating RAP2.12 degradation is indispensable to optimize metabolic performance, plant growth, and development under both normoxic and hypoxic conditions. PMID:27372243

  7. Risk Factors for Acute Kidney Injury and In-Hospital Mortality in Patients Receiving Extracorporeal Membrane Oxygenation

    PubMed Central

    Lee, Sung Woo; Yu, Mi-yeon; Lee, Hajeong; Ahn, Shin Young; Kim, Sejoong; Chin, Ho Jun; Na, Ki Young

    2015-01-01

    Background and Objectives Although acute kidney injury (AKI) is the most frequent complication in patients receiving extracorporeal membrane oxygenation (ECMO), few studies have been conducted on the risk factors of AKI. We performed this study to identify the risk factors of AKI associated with in-hospital mortality. Methods Data from 322 adult patients receiving ECMO were analyzed. AKI and its stages were defined according to Kidney Disease Improving Global Outcomes (KDIGO) classifications. Variables within 24 h before ECMO insertion were collected and analyzed for the associations with AKI and in-hospital mortality. Results Stage 3 AKI was associated with in-hospital mortality, with a hazard ratio (HR) (95% CI) of 2.690 (1.472–4.915) compared to non-AKI (p = 0.001). The simplified acute physiology score 2 (SAPS2) and serum sodium level were also associated with in-hospital mortality, with HRs of 1.02 (1.004–1.035) per 1 score increase (p = 0.01) and 1.042 (1.014–1.070) per 1 mmol/L increase (p = 0.003). The initial pump speed of ECMO was significantly related to in-hospital mortality with a HR of 1.333 (1.020–1.742) per 1,000 rpm increase (p = 0.04). The pump speed was also associated with AKI (p = 0.02) and stage 3 AKI (p = 0.03) with ORs (95% CI) of 2.018 (1.129–3.609) and 1.576 (1.058–2.348), respectively. We also found that the red cell distribution width (RDW) above 14.1% was significantly related to stage 3 AKI. Conclusion The initial pump speed of ECMO was a significant risk factor of in-hospital mortality and AKI in patients receiving ECMO. The RDW was a risk factor of stage 3 AKI. PMID:26469793

  8. The joint effects of sulfonamides and quorum sensing inhibitors on Vibrio fischeri: Differences between the acute and chronic mixed toxicity mechanisms.

    PubMed

    Wang, Ting; Liu, Yuewei; Wang, Dali; Lin, Zhifen; An, Qingqing; Yin, Chunsheng; Liu, Yin

    2016-06-01

    Quorum sensing inhibitors (QSIs) are considered to be promising antibiotic alternatives and will be increasingly exposed to the environment together with antibiotics after their research and development process; it is therefore necessary to study the joint effects of QSIs and antibiotics. In this study, single and mixed toxicity of sulfonamide (SAs) and QSIs under acute and chronic conditions and their corresponding toxicity mechanisms were investigated. The results indicated that the acute joint effect was extremely complex, ranging from an antagonistic to synergistic response, while the chronic joint effect was primarily an antagonistic response. Using a molecular docking and regression model, we found that the acute joint effect could be determined by the hydrion's, ability to be oxidized, as well as the binding energy. The chronic joint effect was primarily an antagonistic response, which was due to the QSI competing against AHL for luxR generated by SAs, leading to negative effects of the QSI-luxR complexes on luxI. This phenomenon eventually weakened the stimulatory effect caused by SAs. Finally, the main differences between acute and chronic mixtures were analyzed: (1) The target protein was different between acute and chronic toxicity mixtures, and (2) effective concentration in acute and chronic toxicity mixtures was also different. These deep insights into mixed toxicity mechanisms will play an important role in the study of antibiotic resistance genes in response to antibiotic replacements. PMID:26897575

  9. Click-assembled, oxygen-sensing nanoconjugates for depth-resolved, near-infrared imaging in a 3D cancer model.

    PubMed

    Nichols, Alexander J; Roussakis, Emmanuel; Klein, Oliver J; Evans, Conor L

    2014-04-01

    Hypoxia is an important contributing factor to the development of drug-resistant cancer, yet few nonperturbative tools exist for studying oxygenation in tissues. While progress has been made in the development of chemical probes for optical oxygen mapping, penetration of such molecules into poorly perfused or avascular tumor regions remains problematic. A click-assembled oxygen-sensing (CAOS) nanoconjugate is reported and its properties demonstrated in an in vitro 3D spheroid cancer model. The synthesis relies on the sequential click-based ligation of poly(amidoamine)-like subunits for rapid assembly. Near-infrared confocal phosphorescence microscopy was used to demonstrate the ability of the CAOS nanoconjugates to penetrate hundreds of micrometers into spheroids within hours and to show their sensitivity to oxygen changes throughout the nodule. This proof-of-concept study demonstrates a modular approach that is readily extensible to a wide variety of oxygen and cellular sensors for depth-resolved imaging in tissue and tissue models. PMID:24590700

  10. Reactive oxygen species in peripheral blood and sputum neutrophils during bacterial and nonbacterial acute exacerbation of chronic obstructive pulmonary disease.

    PubMed

    Vaitkus, Mindaugas; Lavinskiene, Simona; Barkauskiene, Diana; Bieksiene, Kristina; Jeroch, Jolanta; Sakalauskas, Raimundas

    2013-12-01

    Chronic airway inflammation can be mediated by an enhanced neutrophil oxidative burst. However, the role of bacteria in the pathogenesis of chronic obstructive pulmonary disease (COPD) exacerbations is highly controversial. The aim of this study was to evaluate the production of reactive oxygen species (ROS) in peripheral blood and sputum neutrophils during bacterial and nonbacterial acute exacerbations of COPD (AECOPD). A total of 40 patients with AECOPD, 10 healthy nonsmokers, and 10 "healthy" smokers were enrolled into the study. Peripheral blood and sputum samples were obtained during exacerbation and after recovery. Neutrophils were isolated by high-density gradient centrifugation and magnetic separation. ROS production by neutrophils was investigated after stimulation with phorbol-myristate-acetate and Staphylococcus aureus bacteria. ROS production by neutrophils was assessed as the mean fluorescent intensity using a flow cytometer. IL-8 levels in serum and induced sputum were determinant by ELISA. Spontaneous ROS production was significantly higher in neutrophils from the patients with bacterial AECOPD as compared with nonbacterial AECOPD and stable COPD (P <0.05). ROS production stimulated with PMA and with Staphylococcus aureus was significantly higher in neutrophils isolated from the patients with bacterial AECOPD as compared with nonbacterial and stable COPD (P <0.05). The serum and induced sputum IL-8 levels were significantly increased in the patients with bacterial AECOPD than nonbacterial AECOPD, stable COPS, and "healthy" smokers and nonsmokers (P <0.05) and higher in the induced sputum as the compared with serum in all studied groups (P <0.05). Enlarge CRP level was documented during AECOPD than in all other groups (P <0.05). A markedly increased ROS production in sputum neutrophils during bacterial AECOPD shows an inflammatory response reflecting enhanced local inflammation, which can be mediated by bacterial colonization. PMID:23872721

  11. [The state of acid-alkaline balance and oxygen-transport function of blood in patients with acute carotid ischemic stroke].

    PubMed

    Zhdanova, S G; Aliev, E S; Kamchatnov, P R; Mikhaĭlova, N A

    2012-01-01

    The gas composition, acid-alkaline state of arterial and venous blood and oxygen-transport function in carotid ischemic stroke was studied in 97 patients admitted to a hospital in the first 24h after stroke. Measurements were made at admission and after 5-7 days and 21-23 days. The relative hyperoxia, which reached maximal values to the first day, was found in patients in the acute stage of ischemic stroke. The increase in partial pressure of CO2 (pCO2) and relative acidosis seen to 5-7 days represent the compensatory reaction and lead to the increase in affinity of hemoglobin to oxygen thus improving the tissue oxygenation. We found the inverse correlations between the parameters of oxygen delivery (OD) and oxygen consumption (OC) in the first day and the severity of neurological deficit assessed with the NIHSS in the 21-23 days (r = -0.42; p < 0.01 and r = -0.55; p < 0.01 for OD and OC, respectively), i.e., the decrease in oxygen delivery and consumption corresponded to the greater severity of the stroke course. PMID:23390649

  12. Highly distributed multi-point, temperature and pressure compensated, fiber optic oxygen sensors (FOxSense) for aircraft fuel tank environment and safety monitoring

    NASA Astrophysics Data System (ADS)

    Mendoza, Edgar A.; Kempen, Cornelia; Sun, Sunjian; Esterkin, Yan

    2014-09-01

    This paper describes recent progress towards the development and qualification of a highly distributed, multi-point, all optical pressure and temperature compensated, fiber optic oxygen sensor (FOxSense™) system for closed-loop monitoring and safety of the oxygen ullage environment inside fuel tanks of military and commercial aircraft. The alloptical FOxSense™ system uses a passive, multi-parameter (O2/T&P) fiber optic sensor probe with no electrical connections leading to the sensors install within the fuel tanks of an aircraft. The all optical sensor consists of an integrated multi-parameter fiber optic sensor probe that integrates a fuel insensitive fluorescence based optical oxygen optrode with built-in temperature and pressure optical optrodes for compensation of temperature and pressure variants induced in the fluorescence response of the oxygen optrode. The distributed (O2/T&P) fiber optic sensors installed in the fuel tanks of the aircraft are connected to the FOxSense optoelectronic system via a fiber optic cable conduit reaching to each fuel tank in the aircraft. A multichannel frequency-domain fiber optic sensor read-out (FOxSense™) system is used to interrogate the optical signal of all three sensors in real-time and to display the fuel tank oxygen environment suitable for aircraft status and alarm applications. Preliminary testing of the all optical fiber optic oxygen sensor have demonstrated the ability to monitor the oxygen environment inside a simulated fuel tank in the range of 0% O2 to 40% O2 concentrations, temperatures from (-) 40°C to (+) 60°C, and altitudes from 0-ft to 40,000-ft.

  13. New method of preoxygenation for orotracheal intubation in patients with hypoxaemic acute respiratory failure in the intensive care unit, non-invasive ventilation combined with apnoeic oxygenation by high flow nasal oxygen: the randomised OPTINIV study protocol

    PubMed Central

    Jaber, Samir; Molinari, Nicolas; De Jong, Audrey

    2016-01-01

    Introduction Tracheal intubation in the intensive care unit (ICU) is associated with severe life-threatening complications including severe hypoxaemia. Preoxygenation before intubation has been recommended in order to decrease such complications. Non-invasive ventilation (NIV)-assisted preoxygenation allows increased oxygen saturation during the intubation procedure, by applying a positive end-expiratory pressure (PEEP) to prevent alveolar derecruitment. However, the NIV mask has to be taken off after preoxygenation to allow the passage of the tube through the mouth. The patient with hypoxaemia does not receive oxygen during this period, at risk of major hypoxaemia. High-flow nasal cannula oxygen therapy (HFNC) has a potential for apnoeic oxygenation during the apnoea period following the preoxygenation with NIV. Whether application of HFNC combined with NIV is more effective at reducing oxygen desaturation during the intubation procedure compared with NIV alone for preoxygenation in patients with hypoxaemia in the ICU with acute respiratory failure remains to be established. Methods and analysis The HFNC combined to NIV for decreasing oxygen desaturation during the intubation procedure in patients with hypoxaemia in the ICU (OPTINIV) trial is an investigator-initiated monocentre randomised controlled two-arm trial with assessor-blinded outcome assessment. The OPTINIV trial randomises 50 patients with hypoxaemia requiring orotracheal intubation for acute respiratory failure to receive NIV (pressure support=10, PEEP=5, fractional inspired oxygen (FiO2)=100%) combined with HFNC (flow=60 L/min, FiO2=100%, interventional group) or NIV alone (reference group) for preoxygenation. The primary outcome is lowest oxygen saturation during the intubation procedure. Secondary outcomes are intubation-related complications, quality of preoxygenation and ICU mortality. Ethics and dissemination The study project has been approved by the appropriate ethics committee (CPP Sud

  14. Oxygen Deficiency Responsive Gene Expression in Chlamydomonas reinhardtii through a Copper-Sensing Signal Transduction Pathway1

    PubMed Central

    Quinn, Jeanette M.; Eriksson, Mats; Moseley, Jeffrey L.; Merchant, Sabeeha

    2002-01-01

    Chlamydomonas reinhardtii activates Cpx1, Cyc6, and Crd1, encoding, respectively, coproporphyrinogen oxidase, cytochrome c6, and a novel di-iron enzyme when transferred to oxygen-deficient growth conditions. This response is physiologically relevant because C. reinhardtii experiences these growth conditions routinely, and furthermore, one of the target genes, Crd1, is functionally required for normal growth under oxygen-depleted conditions. The same genes are activated also in response to copper-deficiency through copper-response elements that function as target sites for a transcriptional activator. The core of the copper-response element, GTAC, is required also for the hypoxic response, as is a trans-acting locus, CRR1. Mercuric ions, which antagonize the copper-deficiency response, also antagonize the oxygen-deficiency response of these target genes. Taken together, these observations suggest that the oxygen- and copper-deficiency responses share signal transduction components. Nevertheless, whereas the copper-response element is sufficient for the nutritional copper response, the oxygen-deficiency response requires, in addition, a second cis-element, indicating that the response to oxygen depletion is not identical to the nutritional copper response. The distinction between the two responses is also supported by comparative analysis of the response of the target genes, Cyc6, Cpx1, and Crd1, to copper versus oxygen deficiency. A Crr1-independent pathway for Hyd1 expression in oxygen-depleted C. reinhardtii demonstrates the existence of multiple oxygen/redox-responsive circuits in this model organism. PMID:11842150

  15. Oxygen Mapping within Healthy and Acutely Infarcted Brain Tissue in Humans Using the NMR Relaxation of Lipids: A Proof-Of-Concept Translational Study

    PubMed Central

    Magat, Julie; Joudiou, Nicolas; Peeters, André P.; Jordan, Bénédicte F.; Gallez, Bernard; Duprez, Thierry

    2015-01-01

    The clinical applicability of brain oxygenation mapping using the MOBILE (Mapping of Oxygen By Imaging Lipids relaxation Enhancement) magnetic resonance (MR) technique was assessed in the clinical setting of normal brain and of acute cerebral ischemia as a founding proof-of-concept translational study. Changes in the oxygenation level within healthy brain tissue can be detected by analyzing the spin-lattice proton relaxation (‘Global T1’ combining water and lipid protons) because of the paramagnetic properties of molecular oxygen. It was hypothesized that selective measurement of the relaxation of the lipid protons (‘Lipids T1’) would result in enhanced sensitivity of pO2 mapping because of higher solubility of oxygen in lipids than in water, and this was demonstrated in pre-clinical models using the MOBILE technique. In the present study, 12 healthy volunteers and eight patients with acute (48–72 hours) brain infarction were examined with the same clinical 3T MR system. Both Lipids R1 (R1 = 1/T1) and Global R1 were significantly different in the infarcted area and the contralateral unaffected brain tissue, with a higher statistical significance for Lipids R1 (median difference: 0.408 s-1; p<0.0001) than for Global R1 (median difference: 0.154 s-1; p = 0.027). Both Lipids R1 and Global R1 values in the unaffected contralateral brain tissue of stroke patients were not significantly different from the R1 values calculated in the brain tissue of healthy volunteers. The main limitations of the present prototypic version of the MOBILE sequence are the long acquisition time (4 min), hampering robustness of data in uncooperative patients, and a 2 mm slice thickness precluding accurate measurements in small infarcts because of partial volume averaging effects. PMID:26267901

  16. Acute administration of high doses of taurine does not substantially improve high-intensity running performance and the effect on maximal accumulated oxygen deficit is unclear.

    PubMed

    Milioni, Fabio; Malta, Elvis de Souza; Rocha, Leandro George Spinola do Amaral; Mesquita, Camila Angélica Asahi; de Freitas, Ellen Cristini; Zagatto, Alessandro Moura

    2016-05-01

    The aim of the present study was to investigate the effects of acute administration of taurine overload on time to exhaustion (TTE) of high-intensity running performance and alternative maximal accumulated oxygen deficit (MAODALT). The study design was a randomized, placebo-controlled, crossover design. Seventeen healthy male volunteers (age: 25 ± 6 years; maximal oxygen uptake: 50.5 ± 7.6 mL·kg(-1)·min(-1)) performed an incremental treadmill-running test until voluntary exhaustion to determine maximal oxygen uptake and exercise intensity at maximal oxygen uptake. Subsequently, participants completed randomly 2 bouts of supramaximal treadmill-running at 110% exercise intensity at maximal oxygen uptake until exhaustion (placebo (6 g dextrose) or taurine (6 g) supplementation), separated by 1 week. MAODALT was determined using a single supramaximal effort by summating the contribution of the phosphagen and glycolytic pathways. When comparing the results of the supramaximal trials (i.e., placebo and taurine conditions) no differences were observed for high-intensity running TTE (237.70 ± 66.00 and 277.30 ± 40.64 s; p = 0.44) and MAODALT (55.77 ± 8.22 and 55.06 ± 7.89 mL·kg(-1); p = 0.61), which seem to indicate trivial and unclear differences using the magnitude-based inferences approach, respectively. In conclusion, acute 6 g taurine supplementation before exercise did not substantially improve high-intensity running performance and showed an unclear effect on MAODALT. PMID:27109264

  17. A method for measuring brain partial pressure of oxygen in unanesthetized unrestrained subjects: the effect of acute and chronic hypoxia on brain tissue PO2

    PubMed Central

    Ortiz-Prado, E.; Natah, Siraj; Srinivasan, Sathyanarayanan; Dunn, Jeff F.

    2011-01-01

    The level of tissue oxygenation provides information related to the balance between oxygen delivery, oxygen utilization, tissue reactivity and morphology during physiological conditions. Tissue partial pressure of oxygen (PtO2) is influenced by the use of anesthesia or restraint. These factors may impact the absolute level of PtO2. In this study we present a novel fibre optic method to measure brain PtO2. This method can be used in unanesthetized, unrestrained animals, provides absolute values for PO2, has a stable calibration, does not consume oxygen and is MRI compatible. Brain PtO2 was studied during acute hypoxia, as well as before and after 28 days of high altitude acclimatization. A sensor was chronically implanted in the frontal cortex of 8 Wistar rats. It is comprised of a fiber optic probe with a tip containing material that fluoresces with an oxygen dependent lifetime. Brain PtO2 declines by 80% and 76% pre- and post-acclimatization respectively, when the fraction of inspired oxygen declines from 0.21 to 0.08. In addition, a linear relationship between brain PtO2 and inspired O2 levels was demonstrated r2=0.98 and r2=0.99 (pre- and post-acclimatization). Hypoxia acclimatization resulted in an increase in the overall brain PtO2 by approximately 35%. This paper demonstrates the use of a novel chronically implanted fibre optic based sensor for measuring absolute PtO2. It shows a very strong linear relationship in awake animals between inspired O2 and tissue O2, and shows that there is a proportional increase in PtO2 over a range of inspired values after exposure to chronic hypoxia. PMID:20817029

  18. In vivo imaging of hemodynamics and oxygen metabolism in acute focal cerebral ischemic rats with laser speckle imaging and functional photoacoustic microscopy

    NASA Astrophysics Data System (ADS)

    Deng, Zilin; Wang, Zhen; Yang, Xiaoquan; Luo, Qingming; Gong, Hui

    2012-08-01

    Stroke is a devastating disease. The changes in cerebral hemodynamics and oxygen metabolism associated with stroke play an important role in pathophysiology study. But the changes were difficult to describe with a single imaging modality. Here the changes in cerebral blood flow (CBF), cerebral blood volume (CBV), and oxygen saturation (SO2) were yielded with laser speckle imaging (LSI) and photoacoustic microscopy (PAM) during and after 3-h acute focal ischemic rats. These hemodynamic measures were further synthesized to deduce the changes in oxygen extraction fraction (OEF). The results indicate that all the hemodynamics except CBV had rapid declines within 40-min occlusion of middle cerebral artery (MCAO). CBV in arteries and veins first increased to the maximum value of 112.42±36.69% and 130.58±31.01% by 15 min MCAO; then all the hemodynamics had a persistent reduction with small fluctuations during the ischemic. When ischemia lasted for 3 h, CBF in arteries, veins decreased to 17±14.65%, 24.52±20.66%, respectively, CBV dropped to 62±18.56% and 59±18.48%. And the absolute SO2 decreased by 40.52±22.42% and 54.24±11.77%. After 180-min MCAO, the changes in hemodynamics and oxygen metabolism were also quantified. The study suggested that combining LSI and PAM provides an attractive approach for stroke detection in small animal studies.

  19. Enhancing dissolved oxygen control using an on-line hybrid fuzzy-neural soft-sensing model-based control system in an anaerobic/anoxic/oxic process.

    PubMed

    Huang, Mingzhi; Wan, Jinquan; Hu, Kang; Ma, Yongwen; Wang, Yan

    2013-12-01

    An on-line hybrid fuzzy-neural soft-sensing model-based control system was developed to optimize dissolved oxygen concentration in a bench-scale anaerobic/anoxic/oxic (A(2)/O) process. In order to improve the performance of the control system, a self-adapted fuzzy c-means clustering algorithm and adaptive network-based fuzzy inference system (ANFIS) models were employed. The proposed control system permits the on-line implementation of every operating strategy of the experimental system. A set of experiments involving variable hydraulic retention time (HRT), influent pH (pH), dissolved oxygen in the aerobic reactor (DO), and mixed-liquid return ratio (r) was carried out. Using the proposed system, the amount of COD in the effluent stabilized at the set-point and below. The improvement was achieved with optimum dissolved oxygen concentration because the performance of the treatment process was optimized using operating rules implemented in real time. The system allows various expert operational approaches to be deployed with the goal of minimizing organic substances in the outlet while using the minimum amount of energy. PMID:24052227

  20. Ratiometric Molecular Probes Based on Dual Emission of a Blue Fluorescent Coumarin and a Red Phosphorescent Cationic Iridium(III) Complex for Intracellular Oxygen Sensing

    PubMed Central

    Yoshihara, Toshitada; Murayama, Saori; Tobita, Seiji

    2015-01-01

    Ratiometric molecular probes RP1 and RP2 consisting of a blue fluorescent coumarin and a red phosphorescent cationic iridium complex connected by a tetra- or octaproline linker, respectively, were designed and synthesized for sensing oxygen levels in living cells. These probes exhibited dual emission with good spectral separation in acetonitrile. The photorelaxation processes, including intramolecular energy transfer, were revealed by emission quantum yield and lifetime measurements. The ratios (RI=(Ip/If)) between the phosphorescence (Ip) and fluorescence (If) intensities showed excellent oxygen responses; the ratio of RI under degassed and aerated conditions (RI0/RI) was 20.3 and 19.6 for RP1 and RP2. The introduction of the cationic Ir (III) complex improved the cellular uptake efficiency compared to that of a neutral analogue with a tetraproline linker. The emission spectra of the ratiometric probes internalized into living HeLa or MCF-7 cells could be obtained using a conventional microplate reader. The complex RP2 with an octaproline linker provided ratios comparable to the ratiometric measurements obtained using a microplate reader: the ratio of the RI value of RP2 under hypoxia (2.5% O2) to that under normoxia (21% O2) was 1.5 and 1.7 for HeLa and MCF-7 cells, respectively. Thus, the intracellular oxygen levels of MCF-7 cells could be imaged by ratiometric emission measurements using the complex RP2. PMID:26066988

  1. Automated oxygen titration and weaning with FreeO2 in patients with acute exacerbation of COPD: a pilot randomized trial

    PubMed Central

    Lellouche, François; Bouchard, Pierre-Alexandre; Roberge, Maude; Simard, Serge; L’Her, Erwan; Maltais, François; Lacasse, Yves

    2016-01-01

    Introduction We developed a device (FreeO2) that automatically adjusts the oxygen flow rates based on patients’ needs, in order to limit hyperoxia and hypoxemia and to automatically wean them from oxygen. Objective The aim of this study was to evaluate the feasibility of using FreeO2 in patients hospitalized in the respiratory ward for an acute exacerbation of COPD. Methods We conducted a randomized controlled trial comparing FreeO2 vs manual oxygen titration in the respiratory ward of a university hospital. We measured the perception of appropriateness of oxygen titration and monitoring in both groups by nurses and attending physicians using a Likert scale. We evaluated the time in the target range of oxygen saturation (SpO2) as defined for each patient by the attending physician, the time with severe desaturation (SpO2 <85%), and the time with hyperoxia (SpO2 >5% above the target). We also recorded length of stay, intensive care unit admissions, and readmission rate. Fifty patients were randomized (25 patients in both groups; mean age: 72±8 years; mean forced expiratory volume in 1 second: 1.00±0.49 L; and mean initial O2 flow 2.0±1.0 L/min). Results Nurses and attending physicians felt that oxygen titration and monitoring were equally appropriate with both O2 administration systems. The percentage of time within the SpO2 target was significantly higher with FreeO2, and the time with severe desaturation and hyperoxia was significantly reduced with FreeO2. Time from study inclusion to hospital discharge was 5.8±4.4 days with FreeO2 and 8.4±6.0 days with usual oxygen administration (P=0.051). Conclusion FreeO2 was deemed as an appropriate oxygen administration system by nurses and physicians of a respiratory unit. This system maintained SpO2 at the target level better than did manual titration and reduced periods of desaturation and hyperoxia. Our results also suggest that FreeO2 has the potential to reduce the hospital length of stay. PMID:27601891

  2. Remote sensing of cloud-top pressure using reflected solar radiation in the oxygen A-band

    NASA Technical Reports Server (NTRS)

    Wu, M.-L. C.

    1985-01-01

    An algorithm has been developed for using the reflection of solar radiation in the oxygen A-band to determine cloud-top altitude. Because of multiple scattering and molecular absorption inside the cloud, the reflection of clouds is substantially modified in comparison with a mirror cloud, which is assumed to have a 100 percent reflection. To infer true cloud-top altitude, therefore, it is necessary to accurately estimate the amount of 'photon penetration'. Theoretical calculations indicate that the amount of photon penetration depends on the altitude, the scaled volume scattering coefficient, and the scaled optical thickness of the cloud. Algorithms using the reflection in the oxygen A-band to determine the cloud-top pressure have been applied to an aircraft field experiment in conjunction with CCOPE, 1981. Results of this study are very encouraging, especially for extended clouds.

  3. Rescue balloon pulmonary angioplasty under veno-arterial extracorporeal membrane oxygenation in a patient with acute exacerbation of chronic thromboembolic pulmonary hypertension.

    PubMed

    Nakamura, Makiko; Sunagawa, Osahiko; Tsuchiya, Hiroyuki; Miyara, Takafumi; Taba, Yoji; Touma, Takashi; Munakata, Hiroshi; Kugai, Tadao; Okita, Yutaka

    2015-01-01

    We describe a case of a 41-year-old woman with acute exacerbation of chronic thromboembolic pulmonary hypertension (CTEPH) complicated by rapidly progressive respiratory failure and right heart failure with cardiogenic shock. A computed tomography (CT) showed thrombi in the right main pulmonary artery and bilateral peripheral pulmonary arteries, and echocardiography showed right ventricular dilatation and tricuspid regurgitation, with an estimated pressure gradient of 80 mmHg. The patient was initially diagnosed with acute pulmonary thromboembolism, and thrombolytic therapy was administered. Her condition subsequently deteriorated, however, necessitating mechanical ventilation and veno-arterial extracorporeal membrane oxygenation (VA-ECMO). We performed emergency catheter-directed thrombectomy and thrombus aspiration. Pulmonary hypertension (PH) temporarily improved, but subsequently worsened, and the patient was diagnosed with CTEPH. Pulmonary endarterectomy (PEA) was performed. After PEA, we were unable to wean the patient off VA-ECMO, and rescue balloon pulmonary angioplasty (BPA) to the middle and inferior lobe branches of the right lung was performed. Five days after BPA, the patient was removed from VA-ECMO and on the 57th day of hospitalization, she was weaned off the ventilator. The patient was discharged after 139 days of hospitalization. Rescue BPA represents a useful intervention for improving PH and weaning off VA-ECMO in a patient with acute exacerbation of CTEPH. PMID:25742948

  4. Restrictive Fluid Resuscitation Leads to Better Oxygenation than Non-Restrictive Fluid Resuscitation in Piglets with Pulmonary or Extrapulmonary Acute Respiratory Distress Syndrome

    PubMed Central

    Ye, Shunan; Li, Qiujie; Yuan, Shiying; Shu, Huaqing; Yuan, Yin

    2015-01-01

    Background Early goal-directed therapy (EGDT) is used to reduce mortality from septic shock and could be used in early fluid resuscitation of acute respiratory distress syndrome (ARDS). The aim of the present study was to assess the effects of restrictive (RFR) and nonrestrictive fluid resuscitation (NRFR) on hemodynamics, oxygenation, pulmonary function, tissue perfusion, and inflammation in piglets with pulmonary or extrapulmonary ARDS (ARDSp and ARDSexp). Material/Methods Chinese miniature piglets (6–8 weeks; 15±1 kg) were randomly divided into 2 groups (n=12/group) for establishing ARDSp and ARDSexp models, and were further divided into 2 subgroups (n=6/subgroup) for performing RFR and NRFR. Piglets were anesthetized and hemodynamic, pulmonary, and oxygenation indicators were collected at different time points for 6 hours. The goal of EGDT was set for PiCCO parameters (mean arterial pressure (MAP), urine output and cardiac index (CI), and central venous oxygen saturation (ScvO2). Results Piglets under RFR had lower urine output compared with NRFR, as well as lower total fluid volume (P<0.05). EVLW was decreased in ARDSp+RFR and NRFR, as well as in ARDSexp+RFR, but EVLW increased in ARDSexp+NRFR (P<0.05). PaO2/FiO2 decreased in ARDSp using both methods, but was higher with RFR (P<0.05), and was increased in ARDSexp+RFR. Other pulmonary indicators were comparable. The anti-inflammatory cytokines IL-10 and LXA4 were increased in ARDSexp after RFR (P<0.05), but not in the other groups. Conclusions RFR led to better oxygenation in ARDSp and ARDSexp compared with NRFR, but fluid restriction improved oxygenation in ARDSexp only. PMID:26166324

  5. A critical role of acute bronchoconstriction in the mortality associated with high-dose sarin inhalation: Effects of epinephrine and oxygen therapies

    SciTech Connect

    Gundavarapu, Sravanthi; Zhuang, Jianguo; Barrett, Edward G.; Xu, Fadi; Russell, Robert G.; Sopori, Mohan L.

    2014-01-15

    Sarin is an organophosphate nerve agent that is among the most lethal chemical toxins known to mankind. Because of its vaporization properties and ease and low cost of production, sarin is the nerve agent with a strong potential for use by terrorists and rouge nations. The primary route of sarin exposure is through inhalation and, depending on the dose, sarin leads to acute respiratory failure and death. The mechanism(s) of sarin-induced respiratory failure is poorly understood. Sarin irreversibly inhibits acetylcholine esterase, leading to excessive synaptic levels of acetylcholine and, we have previously shown that sarin causes marked ventilatory changes including weakened response to hypoxia. We now show that LD{sub 50} sarin inhalation causes severe bronchoconstriction in rats, leading to airway resistance, increased hypoxia-induced factor-1α, and severe lung epithelium injury. Transferring animals into 60% oxygen chambers after sarin exposure improved the survival from about 50% to 75% at 24 h; however, many animals died within hours after removal from the oxygen chambers. On the other hand, if LD{sub 50} sarin-exposed animals were administered the bronchodilator epinephrine, > 90% of the animals survived. Moreover, while both epinephrine and oxygen treatments moderated cardiorespiratory parameters, the proinflammatory cytokine surge, and elevated expression of hypoxia-induced factor-1α, only epinephrine consistently reduced the sarin-induced bronchoconstriction. These data suggest that severe bronchoconstriction is a critical factor in the mortality induced by LD{sub 50} sarin inhalation, and epinephrine may limit the ventilatory, inflammatory, and lethal effects of sarin. - Highlights: • Inhalation exposure of rats to LD{sub 50} sarin causes death through respiratory failure. • Severe bronchoconstriction is the major cause of sarin-induced respiratory failure. • Transfer of sarin exposed rats to 60% oxygen improves the mortality temporarily.

  6. A critical role of acute bronchoconstriction in the mortality associated with high-dose sarin inhalation: effects of epinephrine and oxygen therapies.

    PubMed

    Gundavarapu, Sravanthi; Zhuang, Jianguo; Barrett, Edward G; Xu, Fadi; Russell, Robert G; Sopori, Mohan L

    2014-01-15

    Sarin is an organophosphate nerve agent that is among the most lethal chemical toxins known to mankind. Because of its vaporization properties and ease and low cost of production, sarin is the nerve agent with a strong potential for use by terrorists and rouge nations. The primary route of sarin exposure is through inhalation and, depending on the dose, sarin leads to acute respiratory failure and death. The mechanism(s) of sarin-induced respiratory failure is poorly understood. Sarin irreversibly inhibits acetylcholine esterase, leading to excessive synaptic levels of acetylcholine and, we have previously shown that sarin causes marked ventilatory changes including weakened response to hypoxia. We now show that LD50 sarin inhalation causes severe bronchoconstriction in rats, leading to airway resistance, increased hypoxia-induced factor-1α, and severe lung epithelium injury. Transferring animals into 60% oxygen chambers after sarin exposure improved the survival from about 50% to 75% at 24h; however, many animals died within hours after removal from the oxygen chambers. On the other hand, if LD50 sarin-exposed animals were administered the bronchodilator epinephrine, >90% of the animals survived. Moreover, while both epinephrine and oxygen treatments moderated cardiorespiratory parameters, the proinflammatory cytokine surge, and elevated expression of hypoxia-induced factor-1α, only epinephrine consistently reduced the sarin-induced bronchoconstriction. These data suggest that severe bronchoconstriction is a critical factor in the mortality induced by LD50 sarin inhalation, and epinephrine may limit the ventilatory, inflammatory, and lethal effects of sarin. PMID:24269878

  7. Role of Dynamin Related Protein 1 (Drp1)-Mediated Mitochondrial Fission in Oxygen-Sensing and Constriction of the Ductus Arteriosus

    PubMed Central

    Hong, Zhigang; Kutty, Shelby; Toth, Peter T.; Marsboom, Glenn; Hammel, James M; Chamberlain, Carolyn; Ryan, John J.; Zhang, Hannah J.; Sharp, Willard W; Morrow, Erik; Trivedi, Kalyani; Weir, E. Kenneth; Archer, Stephen L.

    2014-01-01

    Rationale: Closure of the ductus arteriosus (DA) is essential for the transition from fetal to neonatal patterns of circulation. Initial PO2-dependent vasoconstriction causes functional DA closure within minutes. Within days a fibrogenic, proliferative mechanism causes anatomical closure. Though modulated by endothelial-derived vasodilators and constrictors, O2-sensing is intrinsic to ductal smooth muscle cells (DASMC) and oxygen-induced DA constriction persists in the absence of endothelium, endothelin and cyclooxygenase mediators. O2 increases mitochondrial-derived H2O2 (mitoROS), which constricts DASMC by raising intracellular calcium and activating rho kinase. However, the mechanism by which oxygen changes mitochondrial function is unknown. Objective: Determine whether mitochondrial fission is crucial for O2-induced DA constriction and closure. Methods and Results: Using DA harvested from 30 term infants during correction of congenital heart disease, as well as DA from term rabbits, we demonstrate that mitochondrial fission is crucial for O2-induced constriction and closure. O2 rapidly (<5 minutes) causes mitochondrial fission by a cyclin-dependent kinase-mediated phosphorylation of dynamin-related protein 1 (Drp1) at serine 616. Fission triggers a metabolic shift in the DASMC that activates pyruvate dehydrogenase and increases mitochondrial H2O2 production. Subsequently fission increases complex I activity. Mitochondrial-targeted catalase overexpression eliminates PO2-induced increases in mitoROS and cytosolic calcium. The small-molecule Drp1 inhibitor, Mdivi-1, and siDRP1 yield concordant results, inhibiting O2-induced constriction (without altering the response to phenylephrine or KCl) and preventing O2-induced increases in oxidative metabolism, cytosolic calcium and DASMC proliferation. Prolonged Drp1 inhibition reduces DA closure in a tissue culture model. Conclusions: Mitochondrial fission is an obligatory, early step in mammalian O2-sensing and offers a

  8. Left anterior descending coronary artery blood flow and left ventricular unloading during extracorporeal membrane oxygenation support in a swine model of acute cardiogenic shock.

    PubMed

    Brehm, Christoph; Schubert, Sarah; Carney, Elizabeth; Ghodsizad, Ali; Koerner, Michael; McCoach, Robert; El-Banayosy, Aly

    2015-02-01

    The impact of extracorporeal membrane oxygenation (ECMO) support on coronary blood flow and left ventricular unloading is still debated. This study aimed to further characterize the influence of ECMO on coronary artery blood flow and its ability to unload the left ventricle in a short-term model of acute cardiogenic shock. Seven anesthetized pigs were intubated and then underwent median sternotomy and cannulation for venoarterial (VA) ECMO. Flow in the left anterior descending (LAD) artery, left atrial pressure (LAP), left ventricular end-diastolic pressure (LVEDP), and mean arterial pressure (MAP) were measured before and after esmolol-induced cardiac dysfunction and after initiating VA-ECMO support. Induction of acute cardiogenic shock was associated with short-term increases in LAP from 8 ± 4 mm Hg to 18 ± 14 mm Hg (P = 0.9) and LVEDP from 5 ± 2 mm Hg to 13 ± 17 mm Hg (P = 0.9), and a decrease in MAP from 63 ± 16 mm Hg to 50 ± 24 mm Hg (P = 0.3). With VA-ECMO support, blood flow in the LAD increased from 28 ± 25 mL/min during acute unsupported cardiogenic shock to 67 ± 50 mL/min (P = 0.003), and LAP and LVEDP decreased to 8 + 5 mm Hg (P = 0.7) and 5 ± 3 mm Hg (P = 0.5), respectively. In this swine model of acute cardiogenic shock, VA-ECMO improved coronary blood flow and provided some degree of left ventricular unloading for the short duration of the study. PMID:24935151

  9. Remote sensing of atomic oxygen - Some observational difficulties in the use of the forbidden O I 1173-A and O I 1641-A transitions

    NASA Technical Reports Server (NTRS)

    Erdman, P. W.; Zipf, E. C.

    1987-01-01

    Recent sounding rocket and satellite studies suggest that simultaneous measurements of the O I 989-A and 1304-A resonance lines and of the forbidden 1172.6-A and 1641.3-A transitions would form the basis of a useful remote sensing technique for measuring the O I density and optical opacity of a planetary or stellar atmosphere. Because the 1172.6-A and 1641.3-A emissions are weak lines and are emitted in a wavelength region rich in spectral features, it is important to determine whether typical flight instruments can make measurements with sufficient spectral purity so that the remote sensing observations will yield accurate results. A detailed, high-resolution study of the far UV emission features in the regions surrounding the atomic oxygen transitions at 1172.6 and 1641.3 A was made. These spectra, which were excited by electron impact on O2 and N2, are presented in an attempt to display some potential sources of interference in aeronomical measurements of these O I lines. Both atomic and molecular emissions are found, and the spectral resolution necessary to make unambiguous measurements is discussed.

  10. Cellular oxygen sensing: Importins and exportins are mediators of intracellular localisation of prolyl-4-hydroxylases PHD1 and PHD2

    SciTech Connect

    Steinhoff, Amrei; Pientka, Friederike Katharina; Moeckel, Sylvia; Kettelhake, Antje; Hartmann, Enno; Koehler, Matthias; Depping, Reinhard

    2009-10-02

    Hypoxia-inducible factors are crucial in the regulatory process of oxygen homeostasis of vertebrate cells. Inhibition of prolyl hydroxylation of HIF-{alpha} subunits by prolyl-hydroxylases (PHD1, PHD2 and PHD3) leads to transcription of a greater number of hypoxia responsive genes. We have investigated the subcellular distribution and the molecular mechanisms regulating the intracellular allocation of PHD1 and PHD2. As reported earlier we find PHD1 located exclusively in the nucleus. We demonstrate that nuclear import of PHD1 occurs importin {alpha}/{beta} dependently and relies on a nuclear localisation signal (NLS). By contrast PHD2 is cycling between nucleus and cytoplasm, and nuclear import seems to be independent of 'classical' importin {alpha}/{beta} receptors. Furthermore, we reveal that the exit of PHD2 from the nucleus requires CRM1 and the N-terminal 100 amino acids of the protein. Our findings provide new insights into the mechanisms of the regulation of the oxygen sensor cascade of PHDs in different cellular compartments.

  11. A magnetic mesoporous nanocomposite modified with a ruthenium complex for site-specific molecular oxygen sensing: Construction and characterization

    NASA Astrophysics Data System (ADS)

    Yu-qing, Zhao; Xi, Chen; De-jun, Wan

    2015-08-01

    In this paper, we constructed a core-shell structured organic-inorganic hybrid composite, where superparamagnetic ferroferric oxide and silica molecular sieve MCM-41 were used as the inner core and the outer shell, respectively. A Ru(II) complex was covalently grafted into these MCM-41 tunnels. Electron microscopy images, XRD analysis, IR spectra, thermogravimetry and N2 adsorption/desorption analysis were applied to confirm this Ru(II)-functionalized hybrid composite. Emission of this composite decreased with increasing O2 concentrations, which made itself an O2 sensing system. High selectivity (12.2), linear working curve (linearity = 0.99) and short response time (12 s) were obtained from this composite.

  12. [Effects of oxygen and nikethamide on central drive, ventilation and blood gases of patients with obstructive lung disease in acute exacerbation of respiratory failure].

    PubMed

    Ren, X H; Ding, D J; Chen, E Z

    1993-12-01

    Twelve subjects with COPD in acute exacerbation of respiratory failure were studied. The experiment of each subject was divided into three steps: room air breathing, 35% O2 inhalation for one hour, and then intravenous drip of nikethamide (1.875g) for two hours with 35% oxygen inhalation at the same time. At the end of each step, mouth occlusion pressure (P0.1), VT, VE, VA, VCO2, VD and PaO2, PaCO2 were measured respectively. The results showed that, when breathing air, all the patients presented significant higher P0.1 than normal subjects, indicated higher central drive. After oxygen inhalation, P0.1 decreased markedly, but still higher than normal. No correlation was found between delta P0.1 and delta PaO2. VE declined with the drop of P0.1, but this was due to a decrease of respiratory frequency, while VA remained unchanged (P > 0.05). The increase of PaCO2 was unremarkable. Neither correlation was found between delta VA and delta P0.1, nor between delta VA and delta PaCO2. However, a close correlation existed between delta VCO2/VCO2 and delta VE/VE. The result of our study is not consistent with the postulation, the removal of the hypoxic stimulate after oxygen administration results in a decrease of ventilation and CO2 retention. After nikethamide administration, P0.1 increased as well as VE while VA and PaCO2 remained unchanged. The increase of VE was caused by the increase of respiratory rate. Furthermore, PaO2 decreased in some patients. All of the changes demonstrated that nothing is worthwhile with the treatment of nikethamide, but a side effect from increasing work of breathing and consumption of oxygen.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8033228

  13. Frequency-Stabilized Cavity Ring-Down Spectroscopy of Oxygen and Carbon Dioxide to Support Atmospheric Remote Sensing

    NASA Astrophysics Data System (ADS)

    Long, David Alexander

    Recent remote-sensing satellite missions have aimed to measure global greenhouse gas concentrations with precisions as demanding as 0.25%. These high-resolution measurements should allow for the quantification of carbon sources and sinks, thus, allowing for a considerable reduction in present carbon cycle uncertainties. To achieve these unprecedented measurement goals will require the most precise body of spectroscopic reference data (i.e., laboratory measurements) ever assembled. In order to aid these missions, we have measured ultraprecise spectroscopic parameters for the (30012)←(00001) CO2 band at 1.57 microm and the O2 A-band at 0.76 microm. These near-infrared transitions are utilized in recent greenhouse gas monitoring missions, with the A-band being employed to derive pressure and temperature profiles. In these investigations we have employed frequency-stabilized cavity ring-down spectroscopy (FS-CRDS), a novel ultrasensitive spectroscopic technique. In the O2 A-band we have measured magnetic dipole line parameters for 16O 2 as well as each of the rare isotopologues and have produced calculated, HITRAN-style line lists. Due to the clear presence of collisional narrowing in the spectra, we have utilized the Galatry line profile in these studies and have reported narrowing parameters under self- and air-broadened conditions. We anticipate that the use of these spectral parameters will greatly reduce the uncertainties of atmospheric remote-sensing retrievals. In addition, the spectral fidelity of FS-CRDS allowed us to observe and quantify unresolved hyperfine structure for the 17O-containing isotopologues. Furthermore, the high sensitivity of FS-CRDS enabled measurements of ultraweak (S˜10 -30 cm molec.-1) electric quadrupole transitions in the A-band, many of which had not previously been observed. Recently we have begun a series of studies of the near-infrared CO2 transitions. Measurements at low pressures (<40 kPa) have revealed the simultaneous presence

  14. Effect of the Pulsatile Extracorporeal Membrane Oxygenation on Hemodynamic Energy and Systemic Microcirculation in a Piglet Model of Acute Cardiac Failure.

    PubMed

    Itoh, Hideshi; Ichiba, Shingo; Ujike, Yoshihito; Douguchi, Takuma; Obata, Hideaki; Inamori, Syuji; Iwasaki, Tatsuo; Kasahara, Shingo; Sano, Shunji; Ündar, Akif

    2016-01-01

    The objective of this study was to compare the effects of pulsatile and nonpulsatile extracorporeal membrane oxygenation (ECMO) on hemodynamic energy and systemic microcirculation in an acute cardiac failure model in piglets. Fourteen piglets with a mean body weight of 6.08 ± 0.86 kg were divided into pulsatile (N = 7) and nonpulsatile (N = 7) ECMO groups. The experimental ECMO circuit consisted of a centrifugal pump, a membrane oxygenator, and a pneumatic pulsatile flow generator system developed in-house. Nonpulsatile ECMO was initiated at a flow rate of 140 mL/kg/min for the first 30 min with normal heart beating, with rectal temperature maintained at 36°C. Ventricular fibrillation was then induced with a 3.5-V alternating current to generate a cardiac dysfunction model. Using this model, we collected the data on pulsatile and nonpulsatile groups. The piglets were weaned off ECMO at the end of the experiment (180 min after ECMO was initiated). The animals did not receive blood transfusions, inotropic drugs, or vasoactive drugs. Blood samples were collected to measure hemoglobin, methemoglobin, blood gases, electrolytes, and lactic acid levels. Hemodynamic energy was calculated using the Shepard's energy equivalent pressure. Near-infrared spectroscopy was used to monitor brain and kidney perfusion. The pulsatile ECMO group had a higher atrial pressure (systolic and mean), and significantly higher regional saturation at the brain level, than the nonpulsatile group (for both, P < 0.05). Additionally, the pulsatile ECMO group had higher methemoglobin levels within the normal range than the nonpulsatile group. Our study demonstrated that pulsatile ECMO produces significantly higher hemodynamic energy and improves systemic microcirculation, compared with nonpulsatile ECMO in acute cardiac failure. PMID:26526784

  15. [Impact of acute respiratory failure on survival of COPD patients managed with long-term non-invasive ventilation and oxygen therapy].

    PubMed

    Perrin, C; Vandenbos, F; Tamisier, R; Lemoigne, F; Blaive, B

    2000-02-01

    Our study aimed to assess the impact of acute respiratory failure (ARF) on survival of patients with chronic obstructive pulmonary disease (COPD) receiving long-term oxygen therapy (LTOT) plus nasal intermittent positive pressure ventilation (NIPPV). Survival was analysed retrospectively in 24 patients with severe COPD initiated to NIPPV in addition to LTOT. Fourteen patients were established on NIPPV following exacerbation of acute respiratory failure which has required mechanical ventilation (group 1). Ten patients (group 2) have never been hospitalized for ARF. Comparison of clinical details at baseline, 6 months, 1, 2, and 3 years for the two groups failed to reveal any difference with the exception of prior episodes of ARF. The probability of survival at 3 years was 65% (95% confidence interval [CI] 43-86) for the overall population, 46% (95% CI 15-77) in group 1, and 74% (95% CI 42-105) in group 2. The difference between the two groups was statistically significant. We show that ARF requiring mechanical ventilation appears to be a factor that is negatively correlated with survival for patients treated by LTOT plus NIPPV. This data suggests that NIPPV should be tried before ARF arising in COPD patients who present a deterioration in chronic respiratory failure with hypercapnia. PMID:10756560

  16. Intravenous Immunoglobulin Prevents Murine Antibody-Mediated Acute Lung Injury at the Level of Neutrophil Reactive Oxygen Species (ROS) Production

    PubMed Central

    Semple, John W.; Kim, Michael; Hou, Jing; McVey, Mark; Lee, Young Jin; Tabuchi, Arata; Kuebler, Wolfgang M.; Chai, Zhong-Wei; Lazarus, Alan H.

    2012-01-01

    Transfusion-related acute lung injury (TRALI) is a leading cause of transfusion-associated mortality that can occur with any type of transfusion and is thought to be primarily due to donor antibodies activating pulmonary neutrophils in recipients. Recently, a large prospective case controlled clinical study of cardiac surgery patients demonstrated that despite implementation of male donors, a high incidence of TRALI still occurred and suggested a need for additional interventions in susceptible patient populations. To examine if intravenous immunoglobulin (IVIg) may be effective, a murine model of antibody-mediated acute lung injury that approximates human TRALI was examined. When BALB/c mice were injected with the anti-major histocompatibility complex class I antibody 34-1-2s, mild shock (reduced rectal temperature) and respiratory distress (dyspnea) were observed and pre-treatment of the mice with 2 g/kg IVIg completely prevented these symptoms. To determine IVIg's usefulness to affect severe lung damage, SCID mice, previously shown to be hypersensitive to 34-1-2s were used. SCID mice treated with 34-1-2s underwent severe shock, lung damage (increased wet/dry ratios) and 40% mortality within 2 hours. Treatment with 2 g/kg IVIg 18 hours before 34-1-2s administration completely protected the mice from all adverse events. Treatment with IVIg after symptoms began also reduced lung damage and mortality. While the prophylactic IVIg administration did not affect 34-1-2s-induced pulmonary neutrophil accumulation, bone marrow-derived neutrophils from the IVIg-treated mice displayed no spontaneous ROS production nor could they be stimulated in vitro with fMLP or 34-1-2s. These results suggest that IVIg prevents murine antibody-mediated acute lung injury at the level of neutrophil ROS production and thus, alleviating tissue damage. PMID:22363629

  17. Acute ascorbic acid ingestion increases skeletal muscle blood flow and oxygen consumption via local vasodilation during graded handgrip exercise in older adults.

    PubMed

    Richards, Jennifer C; Crecelius, Anne R; Larson, Dennis G; Dinenno, Frank A

    2015-07-15

    Human aging is associated with reduced skeletal muscle perfusion during exercise, which may be a result of impaired endothelium-dependent dilation and/or attenuated ability to blunt sympathetically mediated vasoconstriction. Intra-arterial infusion of ascorbic acid (AA) increases nitric oxide-mediated vasodilation and forearm blood flow (FBF) during handgrip exercise in older adults, yet it remains unknown whether an acute oral dose can similarly improve FBF or enhance the ability to blunt sympathetic vasoconstriction during exercise. We hypothesized that 1) acute oral AA would improve FBF (Doppler ultrasound) and oxygen consumption (V̇o2) via local vasodilation during graded rhythmic handgrip exercise in older adults (protocol 1), and 2) AA ingestion would not enhance sympatholysis in older adults during handgrip exercise (protocol 2). In protocol 1 (n = 8; 65 ± 3 yr), AA did not influence FBF or V̇o2 during rest or 5% maximal voluntary contraction (MVC) exercise, but increased FBF (199 ± 13 vs. 248 ± 16 ml/min and 343 ± 24 vs. 403 ± 33 ml/min; P < 0.05) and V̇o2 (26 ± 2 vs. 34 ± 3 ml/min and 43 ± 4 vs. 50 ± 5 ml/min; P < 0.05) at both 15 and 25% MVC, respectively. The increased FBF was due to elevations in forearm vascular conductance (FVC). In protocol 2 (n = 10; 63 ± 2 yr), following AA, FBF was similarly elevated during 15% MVC (∼ 20%); however, vasoconstriction to reflex increases in sympathetic activity during -40 mmHg lower-body negative pressure at rest (ΔFVC: -16 ± 3 vs. -16 ± 2%) or during 15% MVC (ΔFVC: -12 ± 2 vs. -11 ± 4%) was unchanged. Our collective results indicate that acute oral ingestion of AA improves muscle blood flow and V̇o2 during exercise in older adults via local vasodilation. PMID:25980023

  18. In-airway molecular flow sensing: A new technology for continuous, noninvasive monitoring of oxygen consumption in critical care

    PubMed Central

    Ciaffoni, Luca; O’Neill, David P.; Couper, John H.; Ritchie, Grant A. D.; Hancock, Gus; Robbins, Peter A.

    2016-01-01

    There are no satisfactory methods for monitoring oxygen consumption in critical care. To address this, we adapted laser absorption spectroscopy to provide measurements of O2, CO2, and water vapor within the airway every 10 ms. The analyzer is integrated within a novel respiratory flow meter that is an order of magnitude more precise than other flow meters. Such precision, coupled with the accurate alignment of gas concentrations with respiratory flow, makes possible the determination of O2 consumption by direct integration over time of the product of O2 concentration and flow. The precision is illustrated by integrating the balance gas (N2 plus Ar) flow and showing that this exchange was near zero. Measured O2 consumption changed by <5% between air and O2 breathing. Clinical capability was illustrated by recording O2 consumption during an aortic aneurysm repair. This device now makes easy, accurate, and noninvasive measurement of O2 consumption for intubated patients in critical care possible. PMID:27532048

  19. The IRP1-HIF-2α axis coordinates iron and oxygen sensing with erythropoiesis and iron absorption.

    PubMed

    Anderson, Sheila A; Nizzi, Christopher P; Chang, Yuan-I; Deck, Kathryn M; Schmidt, Paul J; Galy, Bruno; Damnernsawad, Alisa; Broman, Aimee T; Kendziorski, Christina; Hentze, Matthias W; Fleming, Mark D; Zhang, Jing; Eisenstein, Richard S

    2013-02-01

    Red blood cell production is a finely tuned process that requires coordinated oxygen- and iron-dependent regulation of cell differentiation and iron metabolism. Here, we show that translational regulation of hypoxia-inducible factor 2α (HIF-2α) synthesis by iron regulatory protein 1 (IRP1) is critical for controlling erythrocyte number. IRP1-null (Irp1(-/-)) mice display a marked transient polycythemia. HIF-2α messenger RNA (mRNA) is derepressed in kidneys of Irp1(-/-) mice but not in kidneys of Irp2(-/-) mice, leading to increased renal erythropoietin (Epo) mRNA and inappropriately elevated serum Epo levels. Expression of the iron transport genes DCytb, Dmt1, and ferroportin, as well as other HIF-2α targets, is enhanced in Irp1(-/-) duodenum. Analysis of mRNA translation state in the liver revealed IRP1-dependent dysregulation of HIF-2α mRNA translation, whereas IRP2 deficiency derepressed translation of all other known 5' iron response element (IRE)-containing mRNAs expressed in the liver. These results uncover separable physiological roles of each IRP and identify IRP1 as a therapeutic target for manipulating HIF-2α action in hematologic, oncologic, and other disorders. PMID:23395174

  20. In-airway molecular flow sensing: A new technology for continuous, noninvasive monitoring of oxygen consumption in critical care.

    PubMed

    Ciaffoni, Luca; O'Neill, David P; Couper, John H; Ritchie, Grant A D; Hancock, Gus; Robbins, Peter A

    2016-08-01

    There are no satisfactory methods for monitoring oxygen consumption in critical care. To address this, we adapted laser absorption spectroscopy to provide measurements of O2, CO2, and water vapor within the airway every 10 ms. The analyzer is integrated within a novel respiratory flow meter that is an order of magnitude more precise than other flow meters. Such precision, coupled with the accurate alignment of gas concentrations with respiratory flow, makes possible the determination of O2 consumption by direct integration over time of the product of O2 concentration and flow. The precision is illustrated by integrating the balance gas (N2 plus Ar) flow and showing that this exchange was near zero. Measured O2 consumption changed by <5% between air and O2 breathing. Clinical capability was illustrated by recording O2 consumption during an aortic aneurysm repair. This device now makes easy, accurate, and noninvasive measurement of O2 consumption for intubated patients in critical care possible. PMID:27532048

  1. Oxygen therapy and intraocular oxygenation.

    PubMed Central

    Jampol, L M

    1987-01-01

    When delivered to the corneal surface of rabbits or monkeys, 100% oxygen can significantly increase the pO2 in the aqueous humor. Under hyperbaric conditions (two atmospheres), an observed rise in the aqueous pO2 in rabbits breathing room air can be increased further by exposing the rabbit cornea to 100% oxygen. The high oxygen levels under hyperbaric conditions are mediated by intravascular and transcorneal delivery of oxygen. The increase in the pO2 levels in the aqueous can prevent sickling of intracameral human erythrocytes containing sickle hemoglobin. Thus, oxygen therapy transcorneally or systemically could potentially be used to treat a sickle cell hyphema. The exposure of rabbit eyes to 100% oxygen at the corneal surface is followed by autoregulation (constriction) of the iris vasculature. We could demonstrate no constriction in the eyes of two normal human volunteers or of four patients with chronic stable rubeosis iridis. Preretinal vitreous pO2 levels can be significantly raised by exposing monkeys to hyperbaric 100% oxygen. This procedure may be of value in treating acute, reversible ischemic inner retinal diseases. Transcorneal or vascular delivery of oxygen to the eye under normobaric or hyperbaric conditions may be effective in treating ischemic diseases of the anterior segment, such as anterior segment necrosis or rubeosis iridis, or ischemic inner retinal diseases. Images FIGURE 2 FIGURE 3 FIGURE 4 FIGURE 5 B FIGURE 5 C FIGURE 5 A FIGURE 6 PMID:3447339

  2. Polarimetric remote sensing in oxygen A and B bands: sensitivity study and information content analysis for vertical profile of aerosols

    NASA Astrophysics Data System (ADS)

    Ding, Shouguo; Wang, Jun; Xu, Xiaoguang

    2016-05-01

    Theoretical analysis is conducted to reveal the information content of aerosol vertical profile in space-borne measurements of the backscattered radiance and degree of linear polarization (DOLP) in oxygen (O2) A and B bands. Assuming a quasi-Gaussian shape for aerosol vertical profile characterized by peak height H and half width γ (at half maximum), the Unified Linearized Vector Radiative Transfer Model (UNL-VRTM) is used to simulate the Stokes four-vector elements of upwelling radiation at the top of atmosphere (TOA) and their Jacobians with respect to H and γ. Calculations for different aerosol types and different combinations of H and γ values show that the wide range of gas absorption optical depth in O2 A and B band enables the sensitivity of backscattered DOLP and radiance at TOA to the aerosol layer at different altitudes. Quantitatively, DOLP in O2 A and B bands is found to be more sensitive to H and γ than radiance, especially over the bright surfaces (with large visible reflectance). In many O2 absorption wavelengths, the degree of freedom of signal (DFS) for retrieving H (or γ) generally increases with H (and γ) and can be close to unity in many cases, assuming that the composite uncertainty from surface and aerosol scattering properties as well as measurements is less than 5 %. Further analysis demonstrates that DFS needed for simultaneous retrieval of H and γ can be obtained from a combined use of DOLP measurements at ˜ 10-100 O2 A and B absorption wavelengths (or channels), depending on the specific values of H. The higher the aerosol layer, the fewer number of channels for DOLP measurements in O2 A and B bands are needed for characterizing H and γ. Future hyperspectral measurements of DOLP in O2 A and B bands are needed to continue studying their potential and their combination with radiance and DOLP in atmospheric window channels for retrieving the vertical profiles of aerosols, especially highly scattering aerosols, over land.

  3. Massive Pulmonary Embolism Mimicking Acute Myocardial Infarction: Successful use of extracorporeal membrane oxygenation support as bridge to diagnosis.

    PubMed

    Hsieh, Yung-Kun; Siao, Fu-Yuan; Chiu, Chun-Chieh; Yen, Hsu-Heng; Chen, Yao-Li

    2016-07-01

    Prolonged cardiac arrest with pulseless electrical activity (PEA) results in death if its aetiology cannot be corrected immediately. We describe the case of a 75-year-old man with chest pain and his electrocardiogram (ECG) revealing ST-segment elevation in leads II, III, and aVf. Inferior wall myocardial infarction was subsequently diagnosed. Before performing emergency coronary angiography, however, a sudden cardiac arrest with PEA developed and the patient was placed on advanced cardiac life support. Oxygenation support for the extracorporeal membrane was initiated approximately 65min after prolonged cardiopulmonary resuscitation. Emergency coronary arteriogram showed no obstructive lesions in the right coronary artery. This result, however, was not consistent with the ECG findings, and thus, a massive pulmonary embolism was suspected. Subsequent pulmonary artery angiography showed severe emboli in bilateral branches of the pulmonary arteries. Catheter-directed thrombolysis with urokinase was administered, which ultimately failed, and surgical embolectomy was performed with extracorporeal membrane oxygenation support. After the above intervention, the patient was discharged on hospital day 60 without any sequelae or neurological deficits. PMID:26935163

  4. Acute and long-term effects of hyperbaric oxygen therapy on hemorheological parameters in patients with various disorders.

    PubMed

    Sinan, Mukaddes; Ertan, Nesrin Zeynep; Mirasoglu, Bengusu; Yalcin, Ozlem; Atac, Nazlı; Toklu, Akin Savas; Basaran-Kucukgergin, Canan; Baskurt, Oguz Kerim

    2016-01-01

    Inhalation of 100% oxygen in a hyperbaric chamber has been accepted as a useful treatment for patients with various pathologies who suffer from hypoxia. The oxidative effects of hyperbaric oxygen (HBO) on RBCs have been investigated in animals but there is not enough data on hemorheological parameters in patients following HBO treatment (HBOT).In this study, we investigated the effect of HBO on hemorheological and haematological parameters during treatment. Red blood cell (RBC) deformability and aggregation, blood and plasma viscosity and superoxide dismutase activity were investigated in patients who underwent HBOT. Hematological parameters were determined by an electronic hematology analyzer. A Laser-assisted Optical Rotational Cell Analyzer (LORCA) was used to measure RBC deformability. RBC aggregation was measured for cells in autologous plasma and for cells resuspended in PBS containing Dextran70 (3% ) by using a Myrenne Aggregometer. A Wells-Brookfield cone/plate rotational viscometer was used for viscosity measurements. According to our results, a significant decrement of the hematocrit and the RBC count was observed after the 20th session of HBOT compared to the baseline, but none of the hemorheological parameters changed significantly. Our results showed that HBOT did not cause any significant changes in hemorheological parameters, thereby not representing any problems for the patients. PMID:26410860

  5. THE DETERMINATION OF CORRELATION LINKAGES BETWEEN LEVEL OF REACTIVE OXYGEN SPECIES, CONTENTS OF NEUTROPHILES AND BLOOD GAS COMPOSITION IN EXPERIMENTAL ACUTE LUNG INJURY.

    PubMed

    Marushchak, M; Krynytska, I; Petrenko, N; Klishch, I

    2016-04-01

    Acute lung injury (ALI) remains a major cause of acute respiratory failure and death of patients. Despite the achievements at the current stage in treatment, morbidity and mortality of ALI remain high. However, a deeper understanding of the pathogenetic links of ALI, identifying of the predictors that positively or negatively influence on the course of the syndrome, the correlation between some pathogenetic mechanisms will improve therapeutic strategies for patients with ALI, which makes the actuality of this study. The aim of the research was to detect additional pathogenetic mechanisms of the acute lung injury development in rats based on a comparative analysis of the correlations between the level of reactive oxygen species in blood and bronchoalveolar lavage, contents of neutrophils and blood gas composition. The experiments were performed on 54 white nonlinear mature male rats 200-220g in weight. The animals were divided into 5 groups: the 1st - control group (n=6), the 2nd - animals affected by hydrochloric acid for 2 hours (n=12), the 3rd - animals affected by hydrochloric acid for 6 hours (n=12), the 4th - animals affected by hydrochloric acid for 12 hours (n=12), the 5th - animals affected by hydrochloric acid for 24 hours (n=12). Correlation analysis was performed between all the studied indices. Coefficient of linear correlation (r) and its fidelity (p) was calculated that was accordingly denoted in the tables (correlation matrices). The correlation coefficient was significant at p<0.05. Conducted correlative analysis showed that the level of ROS in neutrophils of blood in rats with modeled ALI had a high negative correlative linkage with pH of arterial blood in 2nd and 3rd experimental groups. Conducted correlative analysis of data in BAL showed that the level of ROS in neutrophils in rats with modeled ALI had a strong positive correlative relationship with the number of white blood cells in 3-rd, 4-th and 5-th experimental groups and positive

  6. Effect of setting high APRV guided by expiratory inflection point of pressure-volume curve on oxygen delivery in canine models of severe acute respiratory distress syndrome

    PubMed Central

    Li, Jia-Qiong; Xu, Hong-Yang; Li, Mao-Qin; Chen, Jing-Yu

    2016-01-01

    In the present study, the effect of setting high airway pressure release ventilation (APRV) pressure guided by an expiratory inflection point of pressure-volume (PV) curve following lung recruitment maneuver (RM) on oxygen delivery (DO2) in canine models of severe acute respiratory distress syndrome (ARDS) was examined. Canine models of severe ARDS were established by intravenous injection of oleic acid. After injection of sedative muscle relaxants, a PV curve plotted using the super-syringe technique, and the pressure at lower inflection point (LIP) at the inhale branch and the pressure at the point of maximum curvature (PMC) at the exhale branch were measured. The ventilation mode was biphasic positive airway pressure (BiPAP), an inspiration to expiration ratio of 1:2, and Phigh 40 cm H2O, Plow 25 cm H2O. Phigh was decreased to 30 cm H2O after 90 sec. The dogs were randomized into 3 groups after RM, i.e., Blip group, BiPAP Plow = LIP+2 cm H2O; Bpmc group, BiPAP Plow = PMC; and Apmc group. In the APRV group, Phigh was set as PMC, with an inspiratory duration of 4 sec and expiratory duration of 0.4 sec. PMC was 18±1.4 cm H2O, and LIP was 11±1.3 cm H2O. Thirty seconds after RM was stabilized, it was set as 0 h. Hemodynamics, oxygenation and DO2 were measured at 0, 1, 2 and 4 h after RM in ARDS dogs. The results demonstrated: i) cardiac index (CI) in the 3 groups, where CI was significantly decreased in the Bpmc group at 0, 1, 2 and 4 h after RM compared to prior to RM (P<0.05) as well as in the Blip and Apmc groups (P<0.05). CI in the Blip and Apmc groups was not significantly altered prior to and after RM. ii) Oxygenation at 0, 1, 2 and 4 h in the 3 groups was improved after RM and the oxygenation indices for the 3 groups at 1 and 2 h were not significantly different (P>0.05). However, the oxygenation index in the Blip group at 4 h was significantly lower than those at 0 h for the Apmc and Bpmc groups (P<0.05). Oxygenation for the Apmc group at 4 h was higher

  7. Direct voltammetric detection of DNA and pH sensing on epitaxial graphene: an insight into the role of oxygenated defects.

    PubMed

    Lim, Cheng Xiang; Hoh, Hui Ying; Ang, Priscilla Kailian; Loh, Kian Ping

    2010-09-01

    In this paper, we carried out detailed electrochemical studies of epitaxial graphene (EG) using inner-sphere and outer-sphere redox mediators. The EG sample was anodized systematically to investigate the effect of edge plane defects on the heterogeneous charge transfer kinetics and capacitive noise. We found that anodized EG, consisting of oxygen-related defects, is a superior biosensing platform for the detection of nucleic acids, uric acids (UA), dopamine (DA), and ascorbic acids (AA). Mixtures of nucleic acids (A, T, C, G) or biomolecules (AA, UA, DA) can be resolved as individual peaks using differential pulse voltammetry. In fact, an anodized EG voltammetric sensor can realize the simultaneous detection of all four DNA bases in double stranded DNA (dsDNA) without a prehydrolysis step, and it can also differentiate single stranded DNA from dsDNA. Our results show that graphene with high edge plane defects, as opposed to pristine graphene, is the choice platform in high resolution electrochemical sensing. PMID:20712323

  8. Phytoglobin: a novel nomenclature for plant globins accepted by the globin community at the 2014 XVIII conference on Oxygen-Binding and Sensing Proteins.

    PubMed

    Hill, Robert; Hargrove, Mark; Arredondo-Peter, Raúl

    2016-01-01

    Hemoglobin (Hb) is a heme-containing protein found in the red blood cells of vertebrates. For many years, the only known Hb-like molecule in plants was leghemoglobin (Lb). The discovery that other Hb-like proteins existed in plants led to the term "nonsymbiotic Hbs (nsHbs)" to differentiate them from the Lbs. While this terminology was adequate in the early stages of research on the protein, the complexity of the research in this area necessitates a change in the definition of these proteins to delineate them from red blood cell Hb. At the 2014 XVIII Conference on Oxygen-Binding and Sensing Proteins, the group devoted to the study of heme-containing proteins, this issue was discussed and a consensus was reached on a proposed name change. We propose Phytoglobin (Phytogb) as a logical, descriptive name to describe a heme-containing (Hb-like) protein found in plants. It will be readily recognized by the research community without a prolonged explanation of the origin of the term. The classification system that has been established can essentially remain unchanged substituting Phytogb in place of nsHb. Here, we present a guide to the new nomenclature, with reference to the existing terminology and a phylogenetic scheme, placing the known Phytogbs in the new nomenclature. PMID:26998237

  9. Phytoglobin: a novel nomenclature for plant globins accepted by the globin community at the 2014 XVIII conference on Oxygen-Binding and Sensing Proteins

    PubMed Central

    Hill, Robert; Hargrove, Mark; Arredondo-Peter, Raúl

    2016-01-01

    Hemoglobin (Hb) is a heme-containing protein found in the red blood cells of vertebrates. For many years, the only known Hb-like molecule in plants was leghemoglobin (Lb). The discovery that other Hb-like proteins existed in plants led to the term “nonsymbiotic Hbs (nsHbs)” to differentiate them from the Lbs. While this terminology was adequate in the early stages of research on the protein, the complexity of the research in this area necessitates a change in the definition of these proteins to delineate them from red blood cell Hb. At the 2014 XVIII Conference on Oxygen-Binding and Sensing Proteins, the group devoted to the study of heme-containing proteins, this issue was discussed and a consensus was reached on a proposed name change. We propose Phytoglobin (Phytogb) as a logical, descriptive name to describe a heme-containing (Hb-like) protein found in plants. It will be readily recognized by the research community without a prolonged explanation of the origin of the term. The classification system that has been established can essentially remain unchanged substituting Phytogb in place of nsHb. Here, we present a guide to the new nomenclature, with reference to the existing terminology and a phylogenetic scheme, placing the known Phytogbs in the new nomenclature. PMID:26998237

  10. Cerebral artery dilatation maintains cerebral oxygenation at extreme altitude and in acute hypoxia—an ultrasound and MRI study

    PubMed Central

    Wilson, Mark H; Edsell, Mark E G; Davagnanam, Indran; Hirani, Shashivadan P; Martin, Dan S; Levett, Denny Z H; Thornton, John S; Golay, Xavier; Strycharczuk, Lisa; Newman, Stanton P; Montgomery, Hugh E; Grocott, Mike P W; Imray, Christopher H E

    2011-01-01

    Transcranial Doppler is a widely used noninvasive technique for assessing cerebral artery blood flow. All previous high altitude studies assessing cerebral blood flow (CBF) in the field that have used Doppler to measure arterial blood velocity have assumed vessel diameter to not alter. Here, we report two studies that demonstrate this is not the case. First, we report the highest recorded study of CBF (7,950 m on Everest) and demonstrate that above 5,300 m, middle cerebral artery (MCA) diameter increases (n=24 at 5,300 m, 14 at 6,400 m, and 5 at 7,950 m). Mean MCA diameter at sea level was 5.30 mm, at 5,300 m was 5.23 mm, at 6,400 m was 6.66 mm, and at 7,950 m was 9.34 mm (P<0.001 for change between 5,300 and 7,950 m). The dilatation at 7,950 m reversed with oxygen. Second, we confirm this dilatation by demonstrating the same effect (and correlating it with ultrasound) during hypoxia (FiO2=12% for 3 hours) in a 3-T magnetic resonance imaging study at sea level (n=7). From these results, we conclude that it cannot be assumed that cerebral artery diameter is constant, especially during alterations of inspired oxygen partial pressure, and that transcranial 2D ultrasound is a technique that can be used at the bedside or in the remote setting to assess MCA caliber. PMID:21654697

  11. Variability in splanchnic tissue oxygenation during preterm red blood cell transfusion given for symptomatic anaemia may reveal a potential mechanism of transfusion-related acute gut injury

    PubMed Central

    Bailey, Sean M.; Hendricks-Muñoz, Karen D.; Mally, Pradeep V.

    2015-01-01

    Background There is increasing evidence indicating an association between red blood cell (RBC) transfusions and necrotising enterocolitis (NEC) in preterm infants, especially late-onset NEC. This phenomenon is referred to as transfusion-related acute gut injury (TRAGI). One theory as to a pathophysiological mechanism is that transfusion may result in an ischemia-reperfusion injury to intestinal tissue. We tested the hypothesis that there is significantly greater variability during transfusion in splanchnic tissue oxygen saturation (SrSO2) than in cerebral tissue oxygen saturation (CrSO2). Materials and methods This was a prospective, observational study using near-infrared spectroscopy to monitor SrSO2 and CrSO2 in preterm neonates undergoing RBC transfusion for symptomatic anaemia. Mean, standard deviation, highest and lowest SrSO2 and CrSO2 values during each transfusion were determined. The greatest difference in SrSO2 and CrSO2 during each transfusion was calculated, along with the coefficient of variation. Results We studied 37 subjects. Throughout all transfusions, the mean SrSO2 was 45.6% ±13.8 and the mean CrSO2 was 65.4% ±6.9 (p<0.001). The variability of SrSO2 was significantly greater than that of CrSO2. Averaging data from all subjects, the greatest difference in SrSO2 was 43.8% ±13.4 compared with 23.3% ±7.6 for CrSO2 (p<0.001). The mean coefficient of variation in all transfusions was 20.5% for SrSO2 and 6.0% for CrSO2 (p<0.001). Increasing post-conceptional age did not affect SrSO2 variability (R2 =0.022; p=0.379), whereas CrSO2 variability during transfusion decreased with increasing post-conceptional age (R2=0.209; p=0.004). Discussion In preterm infants, there is a large degree of tissue oxygenation variability in splanchnic tissue during RBC transfusion and this does not change with increasing maturity. We speculate that these findings, combined with lower average tissue oxygenation, may demonstrate susceptibility of the preterm gut to TRAGI

  12. Hyperbaric oxygen preconditioning protects the lung against acute pancreatitis induced injury via attenuating inflammation and oxidative stress in a nitric oxide dependent manner.

    PubMed

    Yu, Qi-Hong; Zhang, Pei-Xi; Liu, Ying; Liu, Wenwu; Yin, Na

    2016-09-01

    This study aimed to investigate the protective effects of hyperbaric oxygen preconditioning (HBO-PC) on acute pancreatitis AP associated acute lung injury (ALI) and the potential mechanisms. Rats were randomly divided into sham group, AP group, HBO-PC + AP group and HBO-PC + L-NAME group. Rats in HBO-PC + AP group received HBO-PC once daily for 3 days, and AP was introduced 24 h after last HBO-PC. In HBO-PC + L-NAME group, L-NAME (40 mg/kg) was intraperitoneally injected before each HBO-PC. At 24 h after AP, the blood lipase and amylase activities were measured; the lung and pancreas were harvested for pathological examination; the bronchoalveolar lavage fluid was collected for the detection of lactate dehydrogenase (LDH) and proteins; inflammatory factors, superoxide dismutase (SOD) activity and malonaldehyde content were measured in the lung and blood; the Nrf2, SOD-1 and haem oxygenase-1 (HO-1) protein expression was measured in the lung. The lung nitric oxide (NO) and NO synthase activity increased significantly after HBO-PC. HBO-PC was able to reduce blood lipase and amylase activities, improve lung and pancreatic pathology, decrease LDH and proteins in BALF, inhibit the production of inflammatory factors, reduce malonaldehyde content and increase SOD activity in the lung and blood as well as increase protein expression of Nrf2, SOD-1 and HO-1 in the lung. However, L-NAME before HBO-PC significantly attenuated protective effects of HBO-PC. HBO-PC is able to protect the lung against AP induced injury by attenuating inflammation and oxidative stress in the lung via a NO dependent manner. PMID:27453338

  13. Acute oxygen uptake and resistance exercise performance using different rest interval lengths: the influence of maximal aerobic capacity and exercise sequence.

    PubMed

    Ratamess, Nicholas A; Rosenberg, Joseph G; Kang, Jie; Sundberg, Samantha; Izer, Kerrie A; Levowsky, Jaclyn; Rzeszutko, Christina; Ross, Ryan E; Faigenbaum, Avery D

    2014-07-01

    The purpose of this study was to examine the relationship between VO2max and acute resistance exercise performance and the acute metabolic effects of exercise sequencing. Seventeen resistance-trained men were tested for VO2max and 1 repetition maximum (1RM) strength. Subjects were randomly assigned to either a group that performed the squat first in sequence followed by the bench press (S; n = 8) or a group that performed the bench press first followed by the squat (BP; n = 9). Each group performed 3 protocols (using 1-, 2-, or 3-minute rest intervals [RIs] between sets in random order) consisting of 5 sets of each exercise with 75% of their 1RM for up to 10 repetitions while oxygen consumption was measured. Total repetitions completed were highest with 3-minute RI and lowest with 1-minute RI. Mean VO2 was significantly highest with 1-minute RI and lowest using 3-minute RI. Analysis of each exercise revealed a tendency (p = 0.07) for mean bench press VO2 to be higher when it was performed after the squat using 1- and 2-minute RIs. VO2max was significantly negatively correlated to 1RM bench press and squat (r = -0.79 and -0.60, respectively) and was significantly correlated to squat repetitions (r = 0.43-0.57) but did not correlate to bench press performance. It seems that VO2max is related to lower-body resistance exercise performance when short RIs are used, and the metabolic response to the bench press is augmented when it follows the squat in sequence using short RIs. PMID:24714546

  14. Comparison of a New Miniaturized Extracorporeal Membrane Oxygenation System With Integrated Rotary Blood Pump to a Standard System in a Porcine Model of Acute Lung Injury.

    PubMed

    Pilarczyk, Kevin; Heckmann, Jens; Lyskawa, Kathrin; Strauß, Andreas; Haake, Nils; Wiese, Ingo; Jakob, Heinz; Kamler, Markus; Pizanis, Nikolaus

    2016-07-01

    Extracorporeal membrane oxygenation (ECMO) is used for severe acute respiratory distress syndrome. However, available ECMO systems are large and not well designed for fast delivery, emergency implantation, and interhospital transfer. Therefore, a new miniaturized oxygenator with integrated rotary blood pump (ILIAS) was developed and compared with a standard ECMO system in a large animal model. Acute lung injury was induced with repeated pulmonary saline lavage in 14 pigs until PaO2 /FiO2 -ratio was <100 mm Hg with a positive-end-expiratory-pressure of 5 mbar. Pigs were assigned to the following three groups: group 1 (n = 4): control group with conventional ventilation; group 2 (n = 5): standard vv-ECMO; group 3 (n = 5): vv-ILIAS. Gas exchange, hemodynamics, hemolysis, and coagulation activation were examined over a period of 8 h. No device failed during the observation period. PaCO2 decreased from 59.40 ± 4.14 mm Hg to 48.62 ± 4.50 mm Hg after 1 h in the ILIAS group compared with an improvement of PaCO2 from 48.86 ± 7.45 to 40.10 ± 6.02 in the conventional ECMO group (P = not significant [n.s.]). ARDS-induced respiratory acidosis was controlled promptly with a pH of 7.2 ± 0.1 at baseline increasing to 7.4 ± 0.1 in both study groups after 60 min of ECMO support. Mean carbon dioxide transfer was comparable between the conventional ECMO and ILIAS (211.36 ± 78.39 mL/min vs. 219.99 ± 76.72 mL/min, P = n.s.). PaO2 /FiO2 increased from 118.4 ± 15.5 mm Hg to 179.1 ± 72.4 mm Hg in the ILIAS group compared with an improvement of oxygenation from 107.1 ± 24.9 mm Hg to 179.0 ± 45.7 mm Hg in the standard ECMO group (P = n.s.). Mean oxygen transfer was calculated with 136.09 ± 30.25 mL/min for the ILIAS and 129.05 ± 36.28 mL/min for the standard ECMO. Hemodynamic instability or significant activation of the plasmatic coagulation was not

  15. Benzolamide improves oxygenation and reduces acute mountain sickness during a high-altitude trek and has fewer side effects than acetazolamide at sea level.

    PubMed

    Collier, David J; Wolff, Chris B; Hedges, Anne-Marie; Nathan, John; Flower, Rod J; Milledge, James S; Swenson, Erik R

    2016-06-01

    Acetazolamide is the standard carbonic anhydrase (CA) inhibitor used for acute mountain sickness (AMS), however some of its undesirable effects are related to intracellular penetrance into many tissues, including across the blood-brain barrier. Benzolamide is a much more hydrophilic inhibitor, which nonetheless retains a strong renal action to engender a metabolic acidosis and ventilatory stimulus that improves oxygenation at high altitude and reduces AMS. We tested the effectiveness of benzolamide versus placebo in a first field study of the drug as prophylaxis for AMS during an ascent to the Everest Base Camp (5340 m). In two other studies performed at sea level to test side effect differences between acetazolamide and benzolamide, we assessed physiological actions and psychomotor side effects of two doses of acetazolamide (250 and 1000 mg) in one group of healthy subjects and in another group compared acetazolamide (500 mg), benzolamide (200 mg) and lorazepam (2 mg) as an active comparator for central nervous system (CNS) effects. At high altitude, benzolamide-treated subjects maintained better arterial oxygenation at all altitudes (3-6% higher at all altitudes above 4200 m) than placebo-treated subjects and reduced AMS severity by roughly 50%. We found benzolamide had fewer side effects, some of which are symptoms of AMS, than any of the acetazolamide doses in Studies 1 and 2, but equal physiological effects on renal function. The psychomotor side effects of acetazolamide were dose dependent. We conclude that benzolamide is very effective for AMS prophylaxis. With its lesser CNS effects, benzolamide may be superior to acetazolamide, in part, because some of the side effects of acetazolamide may contribute to and be mistaken for AMS. PMID:27433337

  16. No effect of acute beetroot juice ingestion on oxygen consumption, glucose kinetics, or skeletal muscle metabolism during submaximal exercise in males.

    PubMed

    Betteridge, Scott; Bescós, Raúl; Martorell, Miquel; Pons, Antoni; Garnham, Andrew P; Stathis, Christos C; McConell, Glenn K

    2016-02-15

    Beetroot juice, which is rich in nitrate (NO3 (-)), has been shown in some studies to decrease oxygen consumption (V̇o2) for a given exercise workload, i.e., increasing efficiency and exercise tolerance. Few studies have examined the effect of beetroot juice or nitrate supplementation on exercise metabolism. Eight healthy recreationally active males participated in three trials involving ingestion of either beetroot juice (Beet; ∼8 mmol NO3 (-)), Placebo (nitrate-depleted Beet), or Beet + mouthwash (Beet+MW), all of which were performed in a randomized single-blind crossover design. Two-and-a-half hours later, participants cycled for 60 min on an ergometer at 65% of V̇o2 peak. [6,6-(2)H]glucose was infused to determine glucose kinetics, blood samples obtained throughout exercise, and skeletal muscle biopsies that were obtained pre- and postexercise. Plasma nitrite [NO2 (-)] increased significantly (∼130%) with Beet, and this was attenuated in MW+Beet. Beet and Beet+MW had no significant effect on oxygen consumption, blood glucose, blood lactate, plasma nonesterified fatty acids, or plasma insulin during exercise. Beet and Beet+MW also had no significant effect on the increase in glucose disposal during exercise. In addition, Beet and Beet+MW had no significant effect on the decrease in muscle glycogen and phosphocreatine and the increase in muscle creatine, lactate, and phosphorylated acetyl CoA carboxylase during exercise. In conclusion, at the dose used, acute ingestion of beetroot juice had little effect on skeletal muscle metabolism during exercise. PMID:26635348

  17. Systemic oxidative-nitrosative-inflammatory stress during acute exercise in hypoxia; implications for microvascular oxygenation and aerobic capacity.

    PubMed

    Woodside, John D S; Gutowski, Mariusz; Fall, Lewis; James, Philip E; McEneny, Jane; Young, Ian S; Ogoh, Shigehiko; Bailey, Damian M

    2014-12-01

    Exercise performance in hypoxia may be limited by a critical reduction in cerebral and skeletal tissue oxygenation, although the underlying mechanisms remain unclear. We examined whether increased systemic free radical accumulation during hypoxia would be associated with elevated microvascular deoxygenation and reduced maximal aerobic capacity (V̇O2 max ). Eleven healthy men were randomly assigned single-blind to an incremental semi-recumbent cycling test to determine V̇O2 max in both normoxia (21% O2) and hypoxia (12% O2) separated by a week. Continuous-wave near-infrared spectroscopy was employed to monitor concentration changes in oxy- and deoxyhaemoglobin in the left vastus lateralis muscle and frontal cerebral cortex. Antecubital venous blood samples were obtained at rest and at V̇O2 max to determine oxidative (ascorbate radical by electron paramagnetic resonance spectroscopy), nitrosative (nitric oxide metabolites by ozone-based chemiluminescence and 3-nitrotyrosine by enzyme-linked immunosorbent assay) and inflammatory stress biomarkers (soluble intercellular/vascular cell adhesion 1 molecules by enzyme-linked immunosorbent assay). Hypoxia was associated with increased cerebral and muscle tissue deoxygenation and lower V̇O2 max (P < 0.05 versus normoxia). Despite an exercise-induced increase in oxidative-nitrosative-inflammatory stress, hypoxia per se did not have an additive effect (P > 0.05 versus normoxia). Consequently, we failed to observe correlations between any metabolic, haemodynamic and cardiorespiratory parameters (P > 0.05). Collectively, these findings suggest that altered free radical metabolism cannot explain the elevated microvascular deoxygenation and corresponding lower V̇O2 max in hypoxia. Further research is required to determine whether free radicals when present in excess do indeed contribute to the premature termination of exercise in hypoxia. PMID:25344270

  18. Defective quorum sensing of acute lymphoblastic leukemic cells: evidence of collective behavior of leukemic populations as semi-autonomous aberrant ecosystems

    PubMed Central

    Patel, Sapan J; Dao, Su; Darie, Costel C; Clarkson, Bayard D

    2016-01-01

    Quorum sensing (QS) is a generic term used to describe cell-cell communication and collective decision making by bacterial and social insects to regulate the expression of specific genes in controlling cell density and other properties of the populations in response to nutrient supply or changes in the environment. QS mechanisms also have a role in higher organisms in maintaining homeostasis, regulation of the immune system and collective behavior of cancer cell populations. In the present study, we used a p190BCR-ABL driven pre-B acute lymphoblastic leukemia (ALL3) cell line derived from the pleural fluid of a terminally ill patient with ALL to test the QS hypothesis in leukemia. ALL3 cells don’t grow at low density (LD) in liquid media but grow progressively faster at increasingly high cell densities (HD) in contrast to other established leukemic cell lines that grow well at very low starting cell densities. The ALL3 cells at LD are poised to grow but shortly die without additional stimulation. Supernates of ALL3 cells (HDSN) and some other primary cells grown at HD stimulate the growth of the LD ALL3 cells without which they won’t survive. To get further insight into the activation processes we performed microarray analysis of the LD ALL3 cells after stimulation with ALL3 HDSN at days 1, 3, and 6. This screen identified several candidate genes, and we linked them to signaling networks and their functions. We observed that genes involved in lipid, cholesterol, fatty acid metabolism, and B cell activation are most up- or down-regulated upon stimulation of the LD ALL3 cells using HDSN. We also discuss other pathways that are differentially expressed upon stimulation of the LD ALL3 cells. Our findings suggest that the Ph+ ALL population achieves dominance by functioning as a collective aberrant ecosystem subject to defective quorum-sensing regulatory mechanisms. PMID:27429840

  19. Defective quorum sensing of acute lymphoblastic leukemic cells: evidence of collective behavior of leukemic populations as semi-autonomous aberrant ecosystems.

    PubMed

    Patel, Sapan J; Dao, Su; Darie, Costel C; Clarkson, Bayard D

    2016-01-01

    Quorum sensing (QS) is a generic term used to describe cell-cell communication and collective decision making by bacterial and social insects to regulate the expression of specific genes in controlling cell density and other properties of the populations in response to nutrient supply or changes in the environment. QS mechanisms also have a role in higher organisms in maintaining homeostasis, regulation of the immune system and collective behavior of cancer cell populations. In the present study, we used a p190(BCR-ABL) driven pre-B acute lymphoblastic leukemia (ALL3) cell line derived from the pleural fluid of a terminally ill patient with ALL to test the QS hypothesis in leukemia. ALL3 cells don't grow at low density (LD) in liquid media but grow progressively faster at increasingly high cell densities (HD) in contrast to other established leukemic cell lines that grow well at very low starting cell densities. The ALL3 cells at LD are poised to grow but shortly die without additional stimulation. Supernates of ALL3 cells (HDSN) and some other primary cells grown at HD stimulate the growth of the LD ALL3 cells without which they won't survive. To get further insight into the activation processes we performed microarray analysis of the LD ALL3 cells after stimulation with ALL3 HDSN at days 1, 3, and 6. This screen identified several candidate genes, and we linked them to signaling networks and their functions. We observed that genes involved in lipid, cholesterol, fatty acid metabolism, and B cell activation are most up- or down-regulated upon stimulation of the LD ALL3 cells using HDSN. We also discuss other pathways that are differentially expressed upon stimulation of the LD ALL3 cells. Our findings suggest that the Ph+ ALL population achieves dominance by functioning as a collective aberrant ecosystem subject to defective quorum-sensing regulatory mechanisms. PMID:27429840

  20. Intracellular reactive oxygen species are essential for PI3K/Akt/mTOR-dependent IL-7-mediated viability of T-cell acute lymphoblastic leukemia cells.

    PubMed

    Silva, A; Gírio, A; Cebola, I; Santos, C I; Antunes, F; Barata, J T

    2011-06-01

    Interleukin-7 (IL-7) activates phosphoinositide 3-kinase/Akt/mammalian target of rapamycin (PI3K/Akt/mTOR) pathway, thereby mediating viability, proliferation and growth of T-cell acute lymphoblastic leukemia (T-ALL) cells. Reactive oxygen species (ROS) can be upregulated by growth factors and are known to regulate proliferation and viability. Here, we show that IL-7 upregulates ROS in T-ALL cells in a manner that is dependent on PI3K/Akt/mTOR pathway activity and that relies on both NADPH oxidase and mitochondrial respiratory chain. Conversely, IL-7-induced activation of PI3K signaling pathway requires mitochondrial respiration and ROS. We have previously shown that IL-7-mediated activation of PI3K pathway drives the upregulation of the glucose transporter Glut1, promoting glucose uptake in T-ALL cells. Using phloretin to inhibit Glut function, we demonstrate that glucose uptake is mandatory for ROS upregulation in IL-7-treated T-ALL cells, suggesting that IL-7 stimulation leads to increased ROS via PI3K pathway activation and consequent upregulation of Glut1 and glucose uptake. Overall, our data reveal the existence of a critical crosstalk between PI3K/Akt signaling pathway and ROS that is essential for IL-7-mediated T-ALL cell survival, and that may constitute a novel target for therapeutic intervention. PMID:21455214

  1. Mechanotransduction in the Endothelium: Role of Membrane Proteins and Reactive Oxygen Species in Sensing, Transduction, and Transmission of the Signal with Altered Blood Flow

    PubMed Central

    Fisher, Aron B.

    2014-01-01

    Abstract Significance: Changes in shear stress associated with alterations in blood flow initiate a signaling cascade that modulates the vascular phenotype. Shear stress is “sensed” by the endothelium via a mechanosensitive complex on the endothelial cell (EC) membrane that has been characterized as a “mechanosome” consisting of caveolae, platelet endothelial cell adhesion molecule (PECAM), vascular endothelial growth factor receptor 2 (VEGFR2), vascular endothelial (VE)–cadherin, and possibly other elements. This shear signal is transduced by cell membrane ion channels and various kinases and results in the activation of NADPH oxidase (type 2) with the production of reactive oxygen species (ROS). Recent Advances: The signaling cascade associated with stop of shear, as would occur in vivo with various obstructive pathologies, leads to cell proliferation and eventual revascularization. Critical Issues and Future Directions: Although several elements of mechanosensing such as the sensing event, the transduction, transmission, and reception of the mechanosignal are now reasonably well understood, the links among these discrete steps in the pathway are not clear. Thus, identifying the mechanisms for the interaction of the KATP channel, the kinases, and ROS to drive long-term adaptive responses in ECs is necessary. A critical re-examination of the signaling events associated with complex flow patterns (turbulent, oscillatory) under physiological conditions is also essential for the progress in the field. Since these complex shear patterns may be associated with an atherosclerosis susceptible phenotype, a specific challenge will be the pharmacological modulation of the responses to altered signaling events that occur at specific sites of disturbed or obstructed flow. Antioxid. Redox Signal. 20, 899–913. PMID:24328670

  2. Inhibitors of oxygen sensing prolyl hydroxylases regulate nuclear localization of the transcription factors Smad2 and YAP/TAZ involved in CTGF synthesis.

    PubMed

    Preisser, Felix; Giehl, Klaudia; Rehm, Margot; Goppelt-Struebe, Margarete

    2016-08-01

    Pharmacological inhibition of oxygen sensing prolyl hydroxylase domain enzymes (PHDs) has been shown to preserve renal structure and function in various models of kidney disease. Since transforming growth factor β-1 (TGFβ-1) is one of the major mediators of kidney injury, we investigated if inhibition of PHDs with subsequent stabilization of hypoxia inducible transcription factors (HIF) might interfere with TGFβ-1 signaling with special emphasis on its target gene connective tissue growth factor (CTGF). Overnight incubation of human renal tubular cells, primary cells and cell lines, with the PDH inhibitor DMOG increased Smad3 expression, but barely affected Smad2. Both Smads were translocated into the nucleus upon activation of the cells with TGFβ-1. Interestingly, Smad3 nuclear localization was enhanced upon pretreatment of the cells with DMOG for several hours, whereas nuclear Smad2 was reduced. This differential localization was independent of Smad2/3 phosphorylation. Reduced nuclear Smad2 correlated with impaired CTGF secretion in DMOG-treated cells and transient downregulation of Smad2 interfered with TGFβ-1-induced CTGF synthesis. Furthermore, YAP was confirmed as indispensable transcription factor involved in CTGF synthesis. Nuclear localization of YAP and TAZ was reduced in DMOG-treated cells. Our data thus provide evidence for DMOG-mediated reduction of CTGF expression by regulating the nuclear localization of the transcription factors Smad2, YAP and TAZ. Prolonged inhibition of PHDs was necessary to achieve alterations in cellular localization suggesting an indirect HIF-mediated effect. This mechanism might be extended to other transcription factors and target genes, and may thus represent a novel mechanism of negative regulation of gene expression by PHD inhibition. PMID:27155083

  3. Detection of reactive oxygen species (ROS) by the oxidant-sensing probe 2',7'-dichlorodihydrofluorescein diacetate in the cyanobacterium Anabaena variabilis PCC 7937.

    PubMed

    Rastogi, Rajesh P; Singh, Shailendra P; Häder, Donat-P; Sinha, Rajeshwar P

    2010-07-01

    The generation of reactive oxygen species (ROS) under simulated solar radiation (UV-B: 0.30Wm(-2), UV-A: 25.70Wm(-2) and PAR: 118.06Wm(-2)) was studied in the cyanobacterium Anabaena variabilis PCC 7937 using the oxidant-sensing fluorescent probe 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA). DCFH-DA is a nonpolar dye, converted into the polar derivative DCFH by cellular esterases that are nonfluorescent but switched to highly fluorescent DCF when oxidized by intracellular ROS and other peroxides. The images obtained from the fluorescence microscope after 12h of irradiation showed green fluorescence from cells covered with 295, 320 or 395nm cut-off filters, indicating the generation of ROS in all treatments. However, the green/red fluorescence ratio obtained from fluorescence microscopic analysis showed the highest generation of ROS after UV-B radiation in comparison to PAR or UV-A radiation. Production of ROS was also measured by a spectrofluorophotometer and results obtained supported the results of fluorescence microscopy. Low levels of ROS were detected at the start (0h) of the experiment showing that they are generated even during normal metabolism. This study also showed that UV-B radiation causes the fragmentation of the cyanobacterial filaments which could be due to the observed oxidative stress. This is the first report for the detection of intracellular ROS in a cyanobacterium by fluorescence microscopy using DCFH-DA and thereby suggesting the applicability of this method in the study of in vivo generation of ROS. PMID:20570649

  4. Detection of reactive oxygen species (ROS) by the oxidant-sensing probe 2',7'-dichlorodihydrofluorescein diacetate in the cyanobacterium Anabaena variabilis PCC 7937

    SciTech Connect

    Rastogi, Rajesh P.; Singh, Shailendra P.; Haeder, Donat-P.; Sinha, Rajeshwar P.

    2010-07-02

    The generation of reactive oxygen species (ROS) under simulated solar radiation (UV-B: 0.30 Wm{sup -2}, UV-A: 25.70 Wm{sup -2} and PAR: 118.06 Wm{sup -2}) was studied in the cyanobacterium Anabaena variabilis PCC 7937 using the oxidant-sensing fluorescent probe 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA). DCFH-DA is a nonpolar dye, converted into the polar derivative DCFH by cellular esterases that are nonfluorescent but switched to highly fluorescent DCF when oxidized by intracellular ROS and other peroxides. The images obtained from the fluorescence microscope after 12 h of irradiation showed green fluorescence from cells covered with 295, 320 or 395 nm cut-off filters, indicating the generation of ROS in all treatments. However, the green/red fluorescence ratio obtained from fluorescence microscopic analysis showed the highest generation of ROS after UV-B radiation in comparison to PAR or UV-A radiation. Production of ROS was also measured by a spectrofluorophotometer and results obtained supported the results of fluorescence microscopy. Low levels of ROS were detected at the start (0 h) of the experiment showing that they are generated even during normal metabolism. This study also showed that UV-B radiation causes the fragmentation of the cyanobacterial filaments which could be due to the observed oxidative stress. This is the first report for the detection of intracellular ROS in a cyanobacterium by fluorescence microscopy using DCFH-DA and thereby suggesting the applicability of this method in the study of in vivo generation of ROS.

  5. Heme-independent Redox Sensing by the Heme-Nitric Oxide/Oxygen-binding Protein (H-NOX) from Vibrio cholerae.

    PubMed

    Mukhopadyay, Roma; Sudasinghe, Nilusha; Schaub, Tanner; Yukl, Erik T

    2016-08-19

    Heme nitric oxide/oxygen (H-NOX)-binding proteins act as nitric oxide (NO) sensors among various bacterial species. In several cases, they act to mediate communal behavior such as biofilm formation, quorum sensing, and motility by influencing the activity of downstream signaling proteins such as histidine kinases (HisKa) in a NO-dependent manner. An H-NOX/HisKa regulatory circuit was recently identified in Vibrio cholerae, and the H-NOX protein has been spectroscopically characterized. However, the influence of the H-NOX protein on HisKa autophosphorylation has not been evaluated. This process may be important for persistence and pathogenicity in this organism. Here, we have expressed and purified the V. cholerae HisKa (HnoK) and H-NOX in its heme-bound (holo) and heme-free (apo) forms. Autophosphorylation assays of HnoK in the presence of H-NOX show that the holoprotein in the Fe(II)-NO and Fe(III) forms is a potent inhibitor of HnoK. Activity of the Fe(III) form and aerobic instability of the Fe(II) form suggested that Vibrio cholerae H-NOX may act as a sensor of the redox state as well as NO. Remarkably, the apoprotein also showed robust HnoK inhibition that was dependent on the oxidation of cysteine residues to form disulfide bonds at a highly conserved zinc site. The importance of cysteine in this process was confirmed by mutagenesis, which also showed that holo Fe(III), but not Fe(II)-NO, H-NOX relied heavily upon cysteine for activation. These results highlight a heme-independent mechanism for activation of V. cholerae H-NOX that implicates this protein as a dual redox/NO sensor. PMID:27358409

  6. Mechanical Ventilation in Patients with the Acute Respiratory Distress Syndrome and Treated with Extracorporeal Membrane Oxygenation: Impact on Hospital and 30 Day Postdischarge Survival.

    PubMed

    Modrykamien, Ariel M; Hernandez, Omar O; Im, Yunhee; Walters, Ryan W; Schrader, Caleb L; Smith, Lauren E; Lima, Brian

    2016-01-01

    Mechanical ventilation support for acute respiratory distress syndrome (ARDS) patients involves the use of low tidal volumes and positive end-expiratory pressure. Nevertheless, the optimal ventilator strategy for ARDS patients undergoing extracorporeal membrane oxygenation (ECMO) therapy remains unknown. A retrospective analysis of a consecutive series of adult ARDS patients treated with V-V ECMO from October 2012 to May 2015 was performed. Mechanical ventilation data, as well as demographic and clinical data, were collected. We assessed the association between ventilator data and outcomes of interest. The primary outcome was hospital survival. Secondary outcome was 30 day survival posthospital discharge. Sixty-four ARDS patients were treated with ECMO. Univariate analysis showed that plateau pressure was independently associated with hospital survival. Tidal volume, positive end-expiratory pressure (PEEP), and plateau were independently associated with 30 day survival. Multivariate analysis, after controlling for covariates, revealed that a 1 unit increase in plateau pressure was associated with a 21% decrease in the odds of hospital survival (95% confidence interval [CI] = 6.39-33.42%, p = 0.007). In regards to 30 day survival postdischarge, a 1 unit increase in plateau pressure was associated with a 14.4% decrease in the odds of achieving the aforementioned outcome (95% CI = 1.75-25.4%, p = 0.027). Also, a 1 unit increase in PEEP was associated with a 36.2% decrease in the odds of 30 day survival (95% CI = 10.8-54.4%, p = 0.009). Among ARDS patients undergoing ECMO therapy, only plateau pressure is associated with hospital survival. Plateau pressure and PEEP are both associated with 30 day survival posthospital discharge. PMID:27347707

  7. ARDS (Acute Respiratory Distress Syndrome)

    MedlinePlus

    ... Twitter. What Is ARDS? ARDS, or acute respiratory distress syndrome, is a lung condition that leads to low oxygen levels in the blood. ARDS can be life threatening because your body's organs need oxygen-rich ...

  8. Acute mountain sickness

    MedlinePlus

    High altitude cerebral edema; Altitude anoxia; Altitude sickness; Mountain sickness; High altitude pulmonary edema ... Acute mountain sickness is caused by reduced air pressure and lower oxygen levels at high altitudes. The faster you ...

  9. 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.

  10. 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.

  11. Influence of in-plane and bridging oxygen vacancies of SnO2 nanostructures on CH4 sensing at low operating temperatures

    NASA Astrophysics Data System (ADS)

    Bonu, Venkataramana; Das, A.; Prasad, Arun K.; Krishna, Nanda Gopala; Dhara, Sandip; Tyagi, A. K.

    2014-12-01

    Role of "O" defects in sensing pollutant with nanostructured SnO2 is not well understood, especially at low temperatures. SnO2 nanoparticles were grown by soft chemistry route followed by subsequent annealing treatment under specific conditions. Nanowires were grown by chemical vapor deposition technique. A systematic photoluminescence (PL) investigation of "O" defects in SnO2 nanostructures revealed a strong correlation between shallow donors created by the in-plane and the bridging "O" vacancies and gas sensing at low temperatures. These SnO2 nanostructures detected methane (CH4), a reducing and green house gas at a low temperature of 50 °C. Response of CH4 was found to be strongly dependent on surface defect in comparison to surface to volume ratio. Control over "O" vacancies during the synthesis of SnO2 nanomaterials, as supported by X-ray photoelectron spectroscopy and subsequent elucidation for low temperature sensing are demonstrated.

  12. Effect of annealing in a various oxygen atmosphere on structural, optical, electrical and gas sensing properties of MoxOy thin films

    NASA Astrophysics Data System (ADS)

    Arfaoui, A.; Ouni, B.; Touihri, S.; Mhamdi, A.; Labidi, A.; Manoubi, T.

    2015-07-01

    Molybdenum oxide thin films were thermally evaporated on a glass substrate and monitored by an annealing process in a variable oxygen atmosphere. The effects of post annealing condition on the microstructural, morphological, optical and electrical properties were investigated using X-ray diffraction, Raman spectroscopy, atomic force microscope, spectroscopic ellipsometry and impedance spectroscopy. As-deposited amorphous films crystallized into tetragonal metastable phase of Mo5O14 on annealing at 500 °C in vacuum and air. This structure transformed to stable orthorhombic of MoO3 with annealing in oxygen environment. The optical parameters such as the refractive index, extinction coefficient, optical band gap energy and the Urbach energy were calculated from Cauchy formalism. Ellipsometric measurements reveal that the samples present optical gap located between 3.24 and 3.90 eV when the atmosphere becomes rich on oxygen. The variation of the conductivity in terms of the temperature shows an electrical behavior with oxygen environment. Finally, it has been found that MoO3 thin films had high sensitivity to ethanol, which made them as a good candidate for the ethanol sensor.

  13. Morphology and gas sensing characteristics of density-controlled CuO nanostructures obtained by varying the oxygen partial pressure during growth

    NASA Astrophysics Data System (ADS)

    Lee, Dongjin; Jin, Changhyun; Noh, Youngwook; Park, Seokhyun; Choi, Sun-Woo

    2016-07-01

    By exerting different O2 partial pressures (0, 20, 40, and 60 sccm) onto copper substrates, we discovered that the growth parameter, namely, the O2 flow rate, affects the degree of nucleation, diameter, length, and crystalline quality of CuO nanowires (NWs). Scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM) were used to analyze the evolution of the morphological and the microstructural changes in the CuO nanostructures. The formation of a Cu2O interlayer between the Cu and the CuO layers could be adjusted by controlling more precisely the O2 flow rate. In addition, the reducing (H2S) and the oxidizing (O2, NO2, and SO2) gas sensing performances of these O2-assisted CuO NWs were compared with those of CuO NWs grown in static air. The response to the reducing H2S of the sensors based on CuO NWs grown using O2 at 40 sccm showed a higher electrical change and faster response and recovery times than the sensors based on CuO NWs grown using lower O2 flow rates, including the ones grown in static air and/or used for sensing oxidizing gases (O2, NO2, and SO2) did. On the basis of their growth and their gas-sensing applications, the possible mechanisms characteristic of the density-controlled CuO NWs grown using various O2 partial pressures are discussed.

  14. Influence of in-plane and bridging oxygen vacancies of SnO{sub 2} nanostructures on CH{sub 4} sensing at low operating temperatures

    SciTech Connect

    Bonu, Venkataramana Das, A. Prasad, Arun K.; Dhara, Sandip; Tyagi, A. K.; Krishna, Nanda Gopala

    2014-12-15

    Role of “O” defects in sensing pollutant with nanostructured SnO{sub 2} is not well understood, especially at low temperatures. SnO{sub 2} nanoparticles were grown by soft chemistry route followed by subsequent annealing treatment under specific conditions. Nanowires were grown by chemical vapor deposition technique. A systematic photoluminescence (PL) investigation of “O” defects in SnO{sub 2} nanostructures revealed a strong correlation between shallow donors created by the in-plane and the bridging “O” vacancies and gas sensing at low temperatures. These SnO{sub 2} nanostructures detected methane (CH{sub 4}), a reducing and green house gas at a low temperature of 50 °C. Response of CH{sub 4} was found to be strongly dependent on surface defect in comparison to surface to volume ratio. Control over “O” vacancies during the synthesis of SnO{sub 2} nanomaterials, as supported by X-ray photoelectron spectroscopy and subsequent elucidation for low temperature sensing are demonstrated.

  15. Extracorporeal Membrane Oxygenation in Severe Acute Respiratory Failure in Postpartum Woman With Rheumatic Mitral Valve Disease: Benefit, Factors Furthering the Success of This Procedure, and Review of the Literature

    PubMed Central

    Fayad, Georges; Larrue, Benoît; Modine, Thomas; Azzaoui, Richard; Regnault, Alexi; Koussa, Mohammad; Gourlay, Terry; Fourrier, François; Decoene, Christophe; Warembourg, Henri

    2007-01-01

    Abstract: Pregnancy is a common decompensation factor for women with post-rheumatic mitral disease. However, valvular heart diseases causing severe acute respiratory distress are rare. Use of extracorporeal membrane oxygenation (ECMO) early in the event of cardiorespiratory failure after cardiac surgery may be of benefit. Indeed, ECMO cardiopulmonary bypass (CPB) support could help pulmonary recovery if the mitral pathology is involved. A 31-year-old female patient at 30 weeks of amenorrhea was admitted to the obstetrics department with 40°C hyperthermia and New York Heart Association (NYHA) class 4 dyspnea. The patient’s medical history included a post-rheumatic mitral stenosis. Blood gases showed severe hypoxemia associated with hypocapnia. The patient needed to be rapidly intubated and was placed on ventilatory support because of acute respiratory failure. Transesophageal echocardiography showed a severe mitral stenosis, mild mitral insufficiency, and diminished left ventricular function, hypokinetic, dilated right ventricle, and a severe tricuspid regurgitation. An urgent cesarean section was performed. Because of the persistent hemodynamic instability, a mitral valvular replacement and tricuspid valve annuloplasty were performed. In view of the preoperative acute respiratory distress, we decided, at the beginning of the operation, to carry on circulatory support with oxygenation through an ECMO-type CPB at the end of the operation. This decision was totally justified by the unfeasible CPB weaning off. ECMO use led to an efficient hemodynamic state without inotropic drug support. The surgical post-operative course was uneventful. Early use of cardiorespiratory support with veno-arterial ECMO allows pulmonary and right heart recovery after cardiac surgery, thus avoiding the use of inotropic drugs and complex ventilatory support. PMID:17672195

  16. Monitoring the occurrence of seasonal low-oxygen events off the Changjiang Estuary through integration of remote sensing, buoy observations, and modeling

    NASA Astrophysics Data System (ADS)

    Chen, Jianyu; Ni, Xiaobo; Liu, Mingliang; Chen, Jianfang; Mao, Zhihua; Jin, Haiyan; Pan, Delu

    2014-08-01

    Bottom water hypoxia occurs frequently during the summer off the Changjiang Estuary. To estimate its spatial extent and investigate how climatic variations and extreme events may affect its occurrence, we developed a regional statistical model that combines satellite and buoy observations via empirical and statistical relationships. The estimated results were validated using cruise data off the Changjiang Estuary and its adjacent areas. First, we quantified the linkage between the observed dissolved oxygen (DO) concentrations in the bottom water and the chlorophyll-a (Chl-a) concentrations at the surface. With the help of the model, the bottom layer DO concentrations in the region lacking in situ measurements were estimated using the observations near the buoys and the satellite-derived Chl-a concentrations. Comparisons between the modeled results and surveys conducted between 2006 and 2011 indicate that the error of the estimated extent of low-oxygen bottom water was less than 26% and that the bias in the estimated minimum DO concentration was less than 0.5 mg L-1. Both buoy observations and modeled results indicate that the strength of water stratification and the amount of labile organic matter added to the bottom water are the two main factors that control the occurrence and the magnitude of seasonal low-oxygen events off the Changjiang Estuary.

  17. Links between Anr and Quorum Sensing in Pseudomonas aeruginosa Biofilms

    PubMed Central

    Hammond, John H.; Dolben, Emily F.; Smith, T. Jarrod; Bhuju, Sabin

    2015-01-01

    ABSTRACT In Pseudomonas aeruginosa, the transcription factor Anr controls the cellular response to low oxygen or anoxia. Anr activity is high in oxygen-limited environments, including biofilms and populations associated with chronic infections, and Anr is necessary for persistence in a model of pulmonary infection. In this study, we characterized the Anr regulon in biofilm-grown cells at 1% oxygen in the laboratory strain PAO1 and in a quorum sensing (QS)-deficient clinical isolate, J215. As expected, transcripts related to denitrification, arginine fermentation, high-affinity cytochrome oxidases, and CupA fimbriae were lower in the Δanr derivatives. In addition, we observed that transcripts associated with quorum sensing regulation, iron acquisition and storage, type VI secretion, and the catabolism of aromatic compounds were also differentially expressed in the Δanr strains. Prior reports have shown that quorum sensing-defective mutants have higher levels of denitrification, and we found that multiple Anr-regulated processes, including denitrification, were strongly inversely proportional to quorum sensing in both transcriptional and protein-based assays. We also found that in LasR-defective strains but not their LasR-intact counterparts, Anr regulated the production of the 4-hydroxy-2-alkylquinolines, which play roles in quorum sensing and interspecies interactions. These data show that Anr was required for the expression of important metabolic pathways in low-oxygen biofilms, and they reveal an expanded and compensatory role for Anr in the regulation of virulence-related genes in quorum sensing mutants, such as those commonly isolated from infections. IMPORTANCE Pseudomonas aeruginosa causes acute ocular, soft tissue, and pulmonary infections, as well as chronic infections in the airways of cystic fibrosis patients. P. aeruginosa uses quorum sensing (QS) to regulate virulence, but mutations in the gene encoding the master regulator of QS, lasR, are frequently

  18. 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 ...

  19. The acute effects of low flow oxygen and isosorbide dinitrate on left and right ventricular ejection fractions in chronic obstructive pulmonary disease

    SciTech Connect

    Morrison, D.; Caldwell, J.; Lakshminaryan, S.; Ritchie, J.L.; Kennedy, J.W.

    1983-10-01

    The objectives of this study were to determine the effects of low flow oxygen and isosorbide dinitrate on rest and exercise biventricular ejection fractions in patients with chronic obstructive pulmonary disease and to relate these ejection fraction responses to changes in pressure and flow. Nine patients with stable, moderate to severe chronic obstructive pulmonary disease who had no prior history of heart failure performed supine exercise with simultaneous hemodynamic and radionuclide ventriculographic monitoring. Eight patients performed a second exercise during low flow oxygen breathing and five performed a third exercise after ingesting 10 mg oral isosorbide. Oxygen led to a decrease in exercise pulmonary artery pressure in all subjects and a decline in total pulmonary resistance in five of the seven in whom it was measured. Right ventricular ejection fraction increased 0.05 or more only in subjects who had a decrease in total pulmonary resistance. Isosorbide led to an increase in rest and exercise right and left ventricular ejection fractions with simultaneous decreases in pulmonary artery pressure, total pulmonary resistance, blood pressure and arterial oxygen tension. These results suggest that in patients with chronic obstructive pulmonary disease but without a history of right heart failure, the right ventricular systolic functional response to low flow oxygen and isosorbide at rest and exercise is, in part, determined by changes in total pulmonary resistance. The chronic relation between right ventricular ejection fraction and pulmonary hemodynamics in patients with chronic obstructive pulmonary disease remains to be evaluated.

  20. Wound Healing Essentials: Let There Be Oxygen

    PubMed Central

    Sen, Chandan K.

    2009-01-01

    The state of wound oxygenation is a key determinant of healing outcomes. From a diagnostic standpoint, measurements of wound oxygenation are commonly used to guide treatment planning such as amputation decision. In preventive applications, optimizing wound perfusion and providing supplemental O2 in the peri-operative period reduces the incidence of post-operative infections. Correction of wound pO2 may, by itself, trigger some healing responses. Importantly, approaches to correct wound pO2 favorably influence outcomes of other therapies such as responsiveness to growth factors and acceptance of grafts. Chronic ischemic wounds are essentially hypoxic. Primarily based on the tumor literature, hypoxia is generally viewed as being angiogenic. This is true with the condition that hypoxia be acute and mild to modest in magnitude. Extreme near-anoxic hypoxia, as commonly noted in problem wounds, is not compatible with tissue repair. Adequate wound tissue oxygenation is required but may not be sufficient to favorably influence healing outcomes. Success in wound care may be improved by a personalized health care approach. The key lies in our ability to specifically identify the key limitations of a given wound and in developing a multifaceted strategy to specifically address those limitations. In considering approaches to oxygenate the wound tissue it is important to recognize that both too little as well as too much may impede the healing process. Oxygen dosing based on the specific need of a wound therefore seems prudent. Therapeutic approaches targeting the oxygen sensing and redox signaling pathways are promising. PMID:19152646

  1. Investigation of the effects of naratriptan, rizatriptan, and sumatriptan on jugular venous oxygen saturation in anesthetized pigs: implications for their mechanism of acute antimigraine action.

    PubMed

    Létienne, Robert; Verscheure, Yvan; John, Gareth W

    2003-10-01

    The effects of naratriptan, rizatriptan, and sumatriptan on arteriovenous oxygen saturation difference and carotid hemodynamics were compared in the anesthetized pig. Oxygen and carbon dioxide partial pressures in systemic arterial and jugular venous blood as well as hemoglobin oxygen saturation were determined by conventional blood gas analysis. Vehicle (n = 19) or naratriptan, rizatriptan, or sumatriptan (0.63, 2.5, 10, 40, 160, 630, and 2,500 microg/kg i.v.; n = 7/group) were infused cumulatively. In naratriptan-, rizatriptan-, and sumatriptan-treated animals, jugular venous oxygen saturation decreased dose dependently (geometric mean ED50 values of 3.1, 17.9, and 16.0 microg/kg, respectively) concomitantly with increases in carotid vascular resistance. Rizatriptan significantly and dose dependently, from 160 microg/kg, increased PvCO2 (P < 0.05 versus vehicle). Naratriptan and sumatriptan also tended to increase PvCO2 albeit nonstatistically significantly. All three triptans consistently evoked quantitatively similar carotid vasoconstriction, whereas decreases in jugular venous oxygen saturation (VOS) and increases in PvCO2 had different magnitudes and occurred only in around one-half of the animals studied. Maximal variations in PvCO2 were found to correlate highly with those in PvO2 (P = 0.002), but maximal variations in carotid resistance failed to correlate with those in PvCO2 (P = 0.76) or PvO2 (P = 0.28). The results demonstrate that the triptans investigated robustly produced carotid vasoconstriction, but elicited less consistent decreases in VOS and increases in jugular PvCO2, possibly suggestive of distinct mechanisms. Collectively, the data suggest that triptan-induced increases in arteriovenous oxygen saturation difference and carbon dioxide partial pressure in venous blood draining the head are class effects. PMID:12954804

  2. Functionalized ZnO/ZnO2 n-N straddling heterostructure achieved by oxygen plasma bombardment for highly selective methane sensing.

    PubMed

    Ghosh, Sugato; Bhattacharyya, Raghunath; Saha, Hiranmay; Chaudhuri, Chirasree Roy; Mukherjee, Nillohit

    2015-11-01

    Metal oxide semiconductors have been extensively used as reducing gas sensors with major limitations regarding selectivity and operating temperature which is relatively high for most of the cases making the device unusable in some critical situations. Higher operating temperature is also associated with the higher power consumption, which goes against the miniaturization of the device. In order to resolve these problems, here we introduced a ZnO/ZnO2 straddling 'n-N' isotype heterostructure as a highly selective and sensitive methane sensor at moderately low operating temperature. ZnO-Zn(OH)2 precursor films were treated in oxygen plasma in a pulsed DC magnetron sputtering system. Morphological analyses by field emission scanning electron microscopy showed flake like growth of the grains with high surface roughness, whereas X-ray diffraction (XRD) showed polycrystalline nature of the films. Polycrystalline ZnO2 peaks were observed in the XRD pattern in addition to the existing ZnO, which indicates modification of the precursor to oxygen rich heterostructure of ZnO/ZnO2. This was further supported by the shifting of the O1s peak in the X-ray photoelectron spectroscopic analysis. Plasma treated ZnO/ZnO2 heterostructured films were found to show high selectivity towards methane (with respect to H2S and CO) and sensitivity (∼96%) at a comparatively low operating temperature. PMID:26435126

  3. Effects of Acute Bleeding Followed by Hydroxyethyl Starch 130/0.4 or a Crystalloid on Propofol Concentrations, Cerebral Oxygenation, and Electroencephalographic and Haemodynamic Variables in Pigs

    PubMed Central

    Venâncio, Carlos; Souza, Almir P.; Ferreira, Luísa Maria; Branco, Paula Sério; de Pinho, Paula Guedes; Amorim, Pedro; Ferreira, David A.

    2014-01-01

    Bleeding changes the haemodynamics, compromising organ perfusion. In this study, the effects of bleeding followed by replacement with hydroxyethyl starch 130/0.4 (HES) or lactated Ringer's (LR) on cerebral oxygenation and electroencephalogram-derived parameters were investigated. Twelve young pigs under propofol-remifentanil anaesthesia were bled 30 mL/kg and, after a 20-minute waiting period, volume replacement was performed with HES (GHES; N = 6) or LR (GRL; N = 6). Bleeding caused a decrease of more than 50% in mean arterial pressure (P < 0.01) and a decrease in cerebral oximetry (P = 0.039), bispectral index, and electroencephalogram total power (P = 0.04 and P < 0.01, resp.), while propofol plasma concentrations increased (P < 0.01). Both solutions restored the haemodynamics and cerebral oxygenation similarly and were accompanied by an increase in electroencephalogram total power. No differences between groups were found. However, one hour after the end of the volume replacement, the cardiac output (P = 0.03) and the cerebral oxygenation (P = 0.008) decreased in the GLR and were significantly lower than in GHES (P = 0.02). Volume replacement with HES 130/0.4 was capable of maintaining the cardiac output and cerebral oxygenation during a longer period than LR and caused a decrease in the propofol plasma concentrations. PMID:24971192

  4. The Skp1 Protein from Toxoplasma Is Modified by a Cytoplasmic Prolyl 4-Hydroxylase Associated with Oxygen Sensing in the Social Amoeba Dictyostelium*

    PubMed Central

    Xu, Yuechi; Brown, Kevin M.; Wang, Zhuo A.; van der Wel, Hanke; Teygong, Crystal; Zhang, Dongmei; Blader, Ira J.; West, Christopher M.

    2012-01-01

    In diverse types of organisms, cellular hypoxic responses are mediated by prolyl 4-hydroxylases that use O2 and α-ketoglutarate as substrates to hydroxylate conserved proline residues in target proteins. Whereas in metazoans these enzymes control the stability of the HIFα family of transcription factor subunits, the Dictyostelium enzyme (DdPhyA) contributes to O2 regulation of development by a divergent mechanism involving hydroxylation and subsequent glycosylation of DdSkp1, an adaptor subunit in E3SCF ubiquitin ligases. Sequences related to DdPhyA, DdSkp1, and the glycosyltransferases that cap Skp1 hydroxyproline occur also in the genomes of Toxoplasma and other protists, suggesting that this O2 sensing mechanism may be widespread. Here we show by disruption of the TgphyA locus that this enzyme is required for Skp1 glycosylation in Toxoplasma and that disrupted parasites grow slowly at physiological O2 levels. Conservation of cellular function was tested by expression of TgPhyA in DdphyA-null cells. Simple gene replacement did not rescue Skp1 glycosylation, whereas overexpression not only corrected Skp1 modification but also restored the O2 requirement to a level comparable to that of overexpressed DdPhyA. Bacterially expressed TgPhyA protein can prolyl hydroxylate both Toxoplasma and Dictyostelium Skp1s. Kinetic analyses showed that TgPhyA has similar properties to DdPhyA, including a superimposable dependence on the concentration of its co-substrate α-ketoglutarate. Remarkably, however, TgPhyA had a significantly higher apparent affinity for O2. The findings suggest that Skp1 hydroxylation by PhyA is a conserved process among protists and that this biochemical pathway may indirectly sense O2 by detecting the levels of O2-regulated metabolites such as α-ketoglutarate. PMID:22648409

  5. Oxygen radicals and renal diseases.

    PubMed

    Klahr, S

    1997-01-01

    Reactive oxygen metabolites (superoxide, hydrogen peroxide, hydroxyl radical, and hypochlorous acid) are important mediators of renal damage in acute renal failure and glomerular and tubulointerstitial diseases. The role of these oxygen metabolites in the above entities is discussed, and the effects of antioxidants and scavengers of O2 radicals are considered. The role of oxygen radicals in the regulation of gene transcription is also considered. PMID:9387104

  6. DcrA, a c-type heme-containing methyl-accepting protein from Desulfovibrio vulgaris Hildenborough, senses the oxygen concentration or redox potential of the environment.

    PubMed Central

    Fu, R; Wall, J D; Voordouw, G

    1994-01-01

    The amino acid sequence of DcrA from Desulfovibrio vulgaris Hildenborough, a strictly anaerobic, sulfate-reducing bacterium, indicated homology with the methyl-accepting chemotaxis proteins from enteric bacteria (A. Dolla, R. Fu, M. J. Brumlik, and G. Voordouw, J. Bacteriol. 174:1726-1733, 1992). The homology is restricted to the cytoplasmic C-terminal signaling domain. The periplasmic N-terminal sensor domain was found to contain a unique sequence, CHHCH, corresponding to a consensus c-type heme binding site. A pretreated, DcrA-specific polyclonal antiserum, generated against DcrA protein overproduced in Escherichia coli, was used for immunoprecipitation of 35S-labeled DcrA from D. vulgaris and Desulfovibrio desulfuricans G200(pJRFR2), a transconjugant that overexpresses functional DcrA. Labeling of the latter with the heme precursor 5-amino-[4-14C]levulinic acid, followed by immunoprecipitation, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and fluorography, confirmed the presence of c-type heme, while labeling with L-[methyl-3H]methionine in the absence of protein synthesis confirmed that DcrA is a methyl-accepting protein. The base liability of the incorporated radioactivity indicated methyl ester formation like that occurring in the methyl-accepting chemotaxis proteins of enteric bacteria. L-[methyl-3H]methionine labeling of D. desulfuricans G200(pJRFR2) under different conditions indicated that methyl labeling of DcrA decreased upon addition of oxygen and increased upon subsequent addition of the reducing agent dithionite. These results indicate that DcrA may serve as a sensor of oxygen concentration and/or redox potential. Images PMID:8288528

  7. 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.

  8. Complexes trans-Pt(BODIPY)X(PEt3)2: excitation energy-dependent fluorescence and phosphorescence emissions, oxygen sensing and photocatalysis.

    PubMed

    Irmler, Peter; Winter, Rainer F

    2016-06-21

    We report on five new complexes with the general formula trans-Pt(BODIPY)X(PEt3)2 (), where the platinum(ii) ion is σ-bonded to a 4,4-difluoro-4-bora-3a,4a-diaza-s-indacen-8-yl (BODIPY) and an anionic ligand X(-) (X(-) = Cl(-), I(-), NO2(-), NCS(-), CH3(-)). All five complexes were characterized by multinuclear NMR, electronic absorption and luminescence spectroscopy and by X-ray diffraction analysis. Four of these complexes show efficient intersystem crossing (ISC) from an excited singlet state to a BODIPY-centred T1 state and exhibit dual fluorescence and phosphorescence emission from the BODIPY ligand. In , the fluorescence is almost completely quenched, whereas the phosphorescence quantum yield reaches a value of 40%. The rate of ISC and the ratio of phosphorescence to fluorescence emissions depend on the excitation wavelength (i.e. on which specific transition is excited). The performance of these complexes as one-component oxygen sensors and their photocatalytic activities were tested by Stern-Volmer quenching experiments and by monitoring the oxidation of 1,5-dihydroxynaphthalene with (1)O2 generated from the long-lived triplet state of the sensitizer by triplet-triplet annihilation with (3)O2. Exceptionally high (1)O2 generation quantum yields of up to near unity were obtained. PMID:27255789

  9. Acute effects of hexavalent chromium on survival, oxygen consumption, hematological parameters and some biochemical profiles of the Indian major carp, Labeo rohita.

    PubMed

    Vutukuru, S S

    2005-12-01

    An attempt has been made in the present investigation to determine the acute toxicity of hexavalent chromium and its toxicological effects on survival, physiological, hematological and biochemical parameters of the widely consumed Indian major carp, Labeo rohita. Short-term acute toxicity tests were performed adopting renewal bioassay technique (USEPA, 1975) over a period of 96 h, using different concentrations of potassium dichromate to the fish and the 96 h LC[50] value was found to be 111.45 mg/l (Cr(+6) as 39.40 mg/l). ANOVA results showed that the normal respiratory activity of the fish was significantly affected and there is a depression in the metabolic rate at the end of 24, 48, 72 and 96 h exposure. The metal also induced significant decrease (p<0.001) in the hematological parameters of the fish like total erythrocyte count, hemoglobin percent and absolute value Mean cell hemoglobin (MCH) both at the end of 24h and 96 h exposure indicating anemia. Appreciable decline in the biochemical profiles such as total glycogen, total lipids and total protein contents of the fish was also observed. However, the decrease in protein content was significant only at the end of 96 h. This study reflects the extent of the toxic effects of hexavalent chromium and the metal induced cumulative deleterious effects at various functional levels in the widely consumed freshwater fish, Labeo rohita. PMID:16819101

  10. Line selection and sensitivity analysis for oxygen sensing in the 1.26-1.27 micron spectral band for the ASCENDS mission

    NASA Astrophysics Data System (ADS)

    Prasad, N.; Browell, E. V.; Zaccheo, T. S.; Karpowicz, B.

    2010-12-01

    The National Research Council’s (NRC) Decadal Survey (DS) of Earth Science and Applications from Space has identified the Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) as an important atmospheric science mission. The CO2 mixing ratio needs to be measured to a precision of 0.5 percent of background or better (slightly less than 2 ppm) at 100-km horizontal resolution overland and 200-km resolution over oceans. To meet this goal, the ASCENDS mission requires simultaneous laser remote sensing of CO2 and O2 in order to convert CO2 column number densities to average column CO2 mixing ratios (XCO2). As such, the CO2 column number density and the O2 column number density will be utilized to derive the average XCO2 column. NASA Langley Research Center, working with its partners, is developing O2 lidar technology in the 1.26-1.27-μm band for surface pressure measurements. To obtain XCO2 with LAS technique the simultaneous measurement of the CO2 column number density, the O2 column number density for converting the CO2 column number density to XCO2 and the total path length of the measurement are required. The O2 LAS operating at 1.26 μm will be used to convert CO2 number density to mixing ratio. The 1.26-μm spectral band was chosen due to architectural advantage from wavelengths being close to 1.57-μm CO2 LAS column measurements and the favorable spectroscopic characteristics of the O2 absorption line parameters. Furthermore, the surface and atmospheric scattering characteristics from aerosols and thin clouds are nearly the same as for 1.26-μm O2 measurements and the 1.57-μm CO2 measurements. One or more "on-line" wavelengths in the 1.26-μm O2 absorption band have to be carefully chosen to eliminate ambient influences on them when used in conjunction with the integrated path differential absorption (IPDA) technique. The O2 model optical depth calculation is very sensitive to knowledge of the transmitted wavelengths and to the choice of

  11. Selective TNF-α targeting with infliximab attenuates impaired oxygen metabolism and contractile function induced by an acute exposure to air particulate matter.

    PubMed

    Marchini, Timoteo; D'Annunzio, Verónica; Paz, Mariela L; Cáceres, Lourdes; Garcés, Mariana; Perez, Virginia; Tasat, Deborah; Vanasco, Virginia; Magnani, Natalia; Gonzalez Maglio, Daniel; Gelpi, Ricardo J; Alvarez, Silvia; Evelson, Pablo

    2015-11-15

    Inflammation plays a central role in the onset and progression of cardiovascular diseases associated with the exposure to air pollution particulate matter (PM). The aim of this work was to analyze the cardioprotective effect of selective TNF-α targeting with a blocking anti-TNF-α antibody (infliximab) in an in vivo mice model of acute exposure to residual oil fly ash (ROFA). Female Swiss mice received an intraperitoneal injection of infliximab (10 mg/kg body wt) or saline solution, and were intranasally instilled with a ROFA suspension (1 mg/kg body wt). Control animals were instilled with saline solution and handled in parallel. After 3 h, heart O2 consumption was assessed by high-resolution respirometry in left ventricle tissue cubes and isolated mitochondria, and ventricular contractile reserve and lusitropic reserve were evaluated according to the Langendorff technique. ROFA instillation induced a significant decrease in tissue O2 consumption and active mitochondrial respiration by 32 and 31%, respectively, compared with the control group. While ventricular contractile state and isovolumic relaxation were not altered in ROFA-exposed mice, impaired contractile reserve and lusitropic reserve were observed in this group. Infliximab pretreatment significantly attenuated the decrease in heart O2 consumption and prevented the decrease in ventricular contractile and lusitropic reserve in ROFA-exposed mice. Moreover, infliximab-pretreated ROFA-exposed mice showed conserved left ventricular developed pressure and cardiac O2 consumption in response to a β-adrenergic stimulus with isoproterenol. These results provides direct evidence linking systemic inflammation and altered cardiac function following an acute exposure to PM and contribute to the understanding of PM-associated cardiovascular morbidity and mortality. PMID:26386109

  12. Reactive oxygen species produced by NADPH oxidase and mitochondrial dysfunction in lung after an acute exposure to Residual Oil Fly Ashes

    SciTech Connect

    Magnani, Natalia D.; Marchini, Timoteo; Vanasco, Virginia; Tasat, Deborah R.; Alvarez, Silvia; Evelson, Pablo

    2013-07-01

    Reactive O{sub 2} species production triggered by particulate matter (PM) exposure is able to initiate oxidative damage mechanisms, which are postulated as responsible for increased morbidity along with the aggravation of respiratory diseases. The aim of this work was to quantitatively analyse the major sources of reactive O{sub 2} species involved in lung O{sub 2} metabolism after an acute exposure to Residual Oil Fly Ashes (ROFAs). Mice were intranasally instilled with a ROFA suspension (1.0 mg/kg body weight), and lung samples were analysed 1 h after instillation. Tissue O{sub 2} consumption and NADPH oxidase (Nox) activity were evaluated in tissue homogenates. Mitochondrial respiration, respiratory chain complexes activity, H{sub 2}O{sub 2} and ATP production rates, mitochondrial membrane potential and oxidative damage markers were assessed in isolated mitochondria. ROFA exposure was found to be associated with 61% increased tissue O{sub 2} consumption, a 30% increase in Nox activity, a 33% increased state 3 mitochondrial O{sub 2} consumption and a mitochondrial complex II activity increased by 25%. During mitochondrial active respiration, mitochondrial depolarization and a 53% decreased ATP production rate were observed. Neither changes in H{sub 2}O{sub 2} production rate, nor oxidative damage in isolated mitochondria were observed after the instillation. After an acute ROFA exposure, increased tissue O{sub 2} consumption may account for an augmented Nox activity, causing an increased O{sub 2}{sup ·−} production. The mitochondrial function modifications found may prevent oxidative damage within the organelle. These findings provide new insights to the understanding of the mechanisms involving reactive O{sub 2} species production in the lung triggered by ROFA exposure. - Highlights: • Exposure to ROFA alters the oxidative metabolism in mice lung. • The augmented Nox activity contributes to the high tissue O{sub 2} consumption. • Exposure to ROFA

  13. Pyr3, a TRPC3 channel blocker, potentiates dexamethasone sensitivity and apoptosis in acute lymphoblastic leukemia cells by disturbing Ca(2+) signaling, mitochondrial membrane potential changes and reactive oxygen species production.

    PubMed

    Abdoul-Azize, Souleymane; Buquet, Catherine; Vannier, Jean-Pierre; Dubus, Isabelle

    2016-08-01

    Dexamethasone (Dex) is used as a chemotherapeutic drug in the treatment of acute lymphoblastic leukemia (ALL) because of its capacity to induce apoptosis. However, some ALL patients acquire resistance to glucocorticoids (GC). Thus, it is important to explore new agents to overcome GC resistance. The aim of the present work was to assess the ability of Pyr3, a selective inhibitor of transient receptor potential canonical 3 (TRPC3), to sensitize human ALL cells to Dex. We show here, for the first time, that Pyr3 enhances Dex sensitivity through the distraction of Dex-mediated Ca(2+) signaling in ALL cells (in vitro) and primary blasts (ex vivo) associated with mitochondrial-mediated reactive oxygen species production in ALL cells. Pyr3 alone induced Ca(2+) signaling via only endoplasmic reticulum-released Ca(2+) and exerted inhibitory effect on store-operated Ca(2+) entry in dose-dependent manner in ALL cell lines. Pre-incubation of cells with Pyr3 significantly curtailed the thapsigargin- and Dex-evoked Ca(2+) signaling in ALL cell lines. Pyr3 synergistically potentiated Dex lethality, as shown by the induction of cell mortality, G2/M cell cycle arrest and apoptosis in ALL cell lines. Moreover, Pyr3 disrupted Dex-mediated Ca(2+) signaling and increased the sensitivity of Dex-induced cell death in primary blasts from ALL patients. Additional analysis showed that co-treatment with Dex and Pyr3 results in mitochondrial membrane potential depolarization and reactive oxygen species production in ALL cells. Together, Pyr3 exhibited potential therapeutic benefit in combination with Dex to inverse glucocorticoid resistance in human ALL and probably in other lymphoid malignancies. PMID:27179991

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

    PubMed Central

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

    1974-01-01

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

  15. Systemic oxygen delivery by peritoneal perfusion of oxygen microbubbles.

    PubMed

    Feshitan, Jameel A; Legband, Nathan D; Borden, Mark A; Terry, Benjamin S

    2014-03-01

    Severe hypoxemia refractory to pulmonary mechanical ventilation remains life-threatening in critically ill patients. Peritoneal ventilation has long been desired for extrapulmonary oxygenation owing to easy access of the peritoneal cavity for catheterization and the relative safety compared to an extracorporeal circuit. Unfortunately, prior attempts involving direct oxygen ventilation or aqueous perfusates of fluorocarbons or hemoglobin carriers have failed, leading many researchers to abandon the method. We attribute these prior failures to limited mass transfer of oxygen to the peritoneum and have designed an oxygen formulation that overcomes this limitation. Using phospholipid-coated oxygen microbubbles (OMBs), we demonstrate 100% survival for rats experiencing acute lung trauma to at least 2 h. In contrast, all untreated rats and rats treated with peritoneal oxygenated saline died within 30 min. For rats treated with OMBs, hemoglobin saturation and heart rate were at normal levels over the 2-h timeframe. Peritoneal oxygenation with OMBs was therefore shown to be safe and effective, and the method requires less equipment and technical expertise than initiating and maintaining an extracorporeal circuit. Further translation of peritoneal oxygenation with OMBs may provide therapy for acute respiratory distress syndrome arising from trauma, sepsis, pneumonia, aspiration, burns and other pulmonary diseases. PMID:24439406

  16. Oxygen Therapy

    MedlinePlus

    ... 85-95% pure oxygen. The concentrator runs on electricity or a battery. A concentrator for home usually ... systems deliver 100% oxygen, and do not require electricity. A small canister can be filled from the ...

  17. 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.

  18. The Effects of Acutely Administered 3,4-Methylenedioxymethamphetamine on Spontaneous Brain Function in Healthy Volunteers Measured with Arterial Spin Labeling and Blood Oxygen Level–Dependent Resting State Functional Connectivity

    PubMed Central

    Carhart-Harris, Robin L.; Murphy, Kevin; Leech, Robert; Erritzoe, David; Wall, Matthew B.; Ferguson, Bart; Williams, Luke T.J.; Roseman, Leor; Brugger, Stefan; De Meer, Ineke; Tanner, Mark; Tyacke, Robin; Wolff, Kim; Sethi, Ajun; Bloomfield, Michael A.P.; Williams, Tim M.; Bolstridge, Mark; Stewart, Lorna; Morgan, Celia; Newbould, Rexford D.; Feilding, Amanda; Curran, H. Val; Nutt, David J.

    2015-01-01

    Background The compound 3,4-methylenedioxymethamphetamine (MDMA) is a potent monoamine releaser that produces an acute euphoria in most individuals. Methods In a double-blind, placebo-controlled, balanced-order study, MDMA was orally administered to 25 physically and mentally healthy individuals. Arterial spin labeling and seed-based resting state functional connectivity (RSFC) were used to produce spatial maps displaying changes in cerebral blood flow (CBF) and RSFC after MDMA administration. Participants underwent two arterial spin labeling and two blood oxygen level–dependent scans in a 90-minute scan session; MDMA and placebo study days were separated by 1 week. Results Marked increases in positive mood were produced by MDMA. Decreased CBF only was observed after MDMA, and this was localized to the right medial temporal lobe (MTL), thalamus, inferior visual cortex, and the somatosensory cortex. Decreased CBF in the right amygdala and hippocampus correlated with ratings of the intensity of global subjective effects of MDMA. The RSFC results complemented the CBF results, with decreases in RSFC between midline cortical regions, the medial prefrontal cortex, and MTL regions, and increases between the amygdala and hippocampus. There were trend-level correlations between these effects and ratings of intense and positive subjective effects. Conclusions The MTLs appear to be specifically implicated in the mechanism of action of MDMA, but further work is required to elucidate how the drug’s characteristic subjective effects arise from its modulation of spontaneous brain activity. PMID:24495461

  19. Hydroxylated Dimeric Naphthoquinones Increase the Generation of Reactive Oxygen Species, Induce Apoptosis of Acute Myeloid Leukemia Cells and Are Not Substrates of the Multidrug Resistance Proteins ABCB1 and ABCG2

    PubMed Central

    Lapidus, Rena G.; Carter-Cooper, Brandon A.; Sadowska, Mariola; Choi, Eun Yong; Wonodi, Omasiri; Muvarak, Nidal; Natarajan, Karthika; Pidugu, Lakshmi S.; Jaiswal, Anil; Toth, Eric A.; Rassool, Feyruz V.; Etemadi, Arash; Sausville, Edward A.; Baer, Maria R.; Emadi, Ashkan

    2016-01-01

    Selective targeting of the oxidative state, which is a tightly balanced fundamental cellular property, is an attractive strategy for developing novel anti-leukemic chemotherapeutics with potential applications in the treatment of acute myeloid leukemia (AML), a molecularly heterogeneous disease. Dimeric naphthoquinones (BiQs) with the ability to undergo redox cycling and to generate reactive oxygen species (ROS) in cancer cells are a novel class of compounds with unique characteristics that make them excellent candidates to be tested against AML cells. We evaluated the effect of two BiQ analogues and one monomeric naphthoquinone in AML cell lines and primary cells from patients. All compounds possess one halogen and one hydroxyl group on the quinone cores. Dimeric, but not monomeric, naphthoquinones demonstrated significant anti-AML activity in the cell lines and primary cells from patients with favorable therapeutic index compared to normal hematopoietic cells. BiQ-1 effectively inhibited clonogenicity and induced apoptosis as measured by Western blotting and Annexin V staining and mitochondrial membrane depolarization by flow cytometry. BiQ-1 significantly enhances intracellular ROS levels in AML cells and upregulates expression of key anti-oxidant protein, Nrf2. Notably, systemic exposure to BiQ-1 was well tolerated in mice. In conclusion, we propose that BiQ-induced therapeutic augmentation of ROS in AML cells with dysregulation of antioxidants kill leukemic cells while normal cells remain relatively intact. Further studies are warranted to better understand this class of potential chemotherapeutics. PMID:26797621

  20. Sequential Activation of Two Pathogen-Sensing Pathways Required for Type I Interferon Expression and Resistance to an Acute DNA Virus Infection.

    PubMed

    Xu, Ren-Huan; Wong, Eric B; Rubio, Daniel; Roscoe, Felicia; Ma, Xueying; Nair, Savita; Remakus, Sanda; Schwendener, Reto; John, Shinu; Shlomchik, Mark; Sigal, Luis J

    2015-12-15

    Toll-like receptor 9 (TLR9), its adaptor MyD88, the downstream transcription factor interferon regulatory factor 7 (IRF7), and type I interferons (IFN-I) are all required for resistance to infection with ectromelia virus (ECTV). However, it is not known how or in which cells these effectors function to promote survival. Here, we showed that after infection with ECTV, the TLR9-MyD88-IRF7 pathway was necessary in CD11c(+) cells for the expression of proinflammatory cytokines and the recruitment of inflammatory monocytes (iMos) to the draining lymph node (dLN). In the dLN, the major producers of IFN-I were infected iMos, which used the DNA sensor-adaptor STING to activate IRF7 and nuclear factor κB (NF-κB) signaling to induce the expression of IFN-α and IFN-β, respectively. Thus, in vivo, two pathways of DNA pathogen sensing act sequentially in two distinct cell types to orchestrate resistance to a viral disease. PMID:26682986

  1. 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

  2. Acute Bronchitis

    MedlinePlus

    ... or though physical contact (for example, on unwashed hands). Being exposed to tobacco smoke, air pollution, dusts, vapors, and fumes can also cause acute bronchitis. Less often, bacteria can also cause acute bronchitis. To diagnose acute ...

  3. Cystitis - acute

    MedlinePlus

    Uncomplicated urinary tract infection; UTI - acute; Acute bladder infection; Acute bacterial cystitis ... control. Menopause also increases the risk for a urinary tract infection. The following also increase your chances of having ...

  4. Oxygen in demand: How oxygen has shaped vertebrate physiology.

    PubMed

    Dzal, Yvonne A; Jenkin, Sarah E M; Lague, Sabine L; Reichert, Michelle N; York, Julia M; Pamenter, Matthew E

    2015-08-01

    In response to varying environmental and physiological challenges, vertebrates have evolved complex and often overlapping systems. These systems detect changes in environmental oxygen availability and respond by increasing oxygen supply to the tissues and/or by decreasing oxygen demand at the cellular level. This suite of responses is termed the oxygen transport cascade and is comprised of several components. These components include 1) chemosensory detectors that sense changes in oxygen, carbon dioxide, and pH in the blood, and initiate changes in 2) ventilation and 3) cardiac work, thereby altering the rate of oxygen delivery to, and carbon dioxide clearance from, the tissues. In addition, changes in 4) cellular and systemic metabolism alters tissue-level metabolic demand. Thus the need for oxygen can be managed locally when increasing oxygen supply is not sufficient or possible. Together, these mechanisms provide a spectrum of responses that facilitate the maintenance of systemic oxygen homeostasis in the face of environmental hypoxia or physiological oxygen depletion (i.e. due to exercise or disease). Bill Milsom has dedicated his career to the study of these responses across phylogenies, repeatedly demonstrating the power of applying the comparative approach to physiological questions. The focus of this review is to discuss the anatomy, signalling pathways, and mechanics of each step of the oxygen transport cascade from the perspective of a Milsomite. That is, by taking into account the developmental, physiological, and evolutionary components of questions related to oxygen transport. We also highlight examples of some of the remarkable species that have captured Bill's attention through their unique adaptations in multiple components of the oxygen transport cascade, which allow them to achieve astounding physiological feats. Bill's research examining the oxygen transport cascade has provided important insight and leadership to the study of the diverse suite

  5. 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.

  6. DEVICE FOR CONTROL OF OXYGEN PARTIAL PRESSURE

    DOEpatents

    Bradner, H.; Gordon, H.S.

    1957-12-24

    A device is described that can sense changes in oxygen partial pressure and cause a corresponding mechanical displacement sufficient to actuate meters, valves and similar devices. A piston and cylinder arrangement contains a charge of crystalline metal chelate pellets which have the peculiar property of responding to variations in the oxygen content of the ambient atmosphere by undergoing a change in dimension. A lever system amplifies the relative displacement of the piston in the cylinder, and actuates the controlled valving device. This partial pressure oxygen sensing device is useful in controlled chemical reactions or in respiratory devices such as the oxygen demand meters for high altitude aircraft.

  7. Gas sensing in nematodes.

    PubMed

    Carrillo, M A; Hallem, E A

    2015-01-01

    Nearly all animals are capable of sensing changes in environmental oxygen (O2) and carbon dioxide (CO2) levels, which can signal the presence of food, pathogens, conspecifics, predators, or hosts. The free-living nematode Caenorhabditis elegans is a powerful model system for the study of gas sensing. C. elegans detects changes in O2 and CO2 levels and integrates information about ambient gas levels with other internal and external cues to generate context-appropriate behavioral responses. Due to its small nervous system and amenability to genetic and genomic analyses, the functional properties of its gas-sensing microcircuits can be dissected with single-cell resolution, and signaling molecules and natural genetic variations that modulate gas responses can be identified. Here, we discuss the neural basis of gas sensing in C. elegans, and highlight changes in gas-evoked behaviors in the context of other sensory cues and natural genetic variations. We also discuss gas sensing in other free-living nematodes and parasitic nematodes, focusing on how gas-sensing behavior has evolved to mediate species-specific behavioral requirements. PMID:24906953

  8. Oxygen control of breathing by an olfactory receptor activated by lactate

    PubMed Central

    Chang, Andy J.; Ortega, Fabian E.; Riegler, Johannes; Madison, Daniel V.; Krasnow, Mark A.

    2015-01-01

    Summary Animals have evolved homeostatic responses to changes in oxygen availability that act on different time scales. Although the hypoxia-inducible factor (HIF) transcriptional pathway that controls long term responses to low oxygen (hypoxia) has been established1, the pathway that mediates acute responses to hypoxia in mammals is not well understood. Here we show that the olfactory receptor Olfr78 is highly and selectively expressed in oxygen-sensitive glomus cells of the carotid body, a chemosensory organ at the carotid artery bifurcation that monitors blood oxygen and stimulates breathing within seconds when oxygen declines2. Olfr78 mutants fail to increase ventilation in hypoxia but respond normally to hypercapnia. Glomus cells are present in normal numbers and appear structurally intact, but hypoxia-induced carotid body activity is diminished. Lactate, a metabolite that rapidly accumulates in hypoxia and induces hyperventilation3–6, activates Olfr78 in heterologous expression experiments, induces calcium transients in glomus cells, and stimulates carotid sinus nerve activity through Olfr78. We propose that in addition to its role in olfaction, Olfr78 acts as a hypoxia sensor in the breathing circuit by sensing lactate produced when oxygen levels decline. PMID:26560302

  9. Functional Oxygen Sensitivity of Astrocytes

    PubMed Central

    Angelova, Plamena R.; Kasymov, Vitaliy; Christie, Isabel; Sheikhbahaei, Shahriar; Turovsky, Egor; Marina, Nephtali; Korsak, Alla; Zwicker, Jennifer; Teschemacher, Anja G.; Ackland, Gareth L.; Funk, Gregory D.; Kasparov, Sergey; Abramov, Andrey Y.

    2015-01-01

    In terrestrial mammals, the oxygen storage capacity of the CNS is limited, and neuronal function is rapidly impaired if oxygen supply is interrupted even for a short period of time. However, oxygen tension monitored by the peripheral (arterial) chemoreceptors is not sensitive to regional CNS differences in partial pressure of oxygen (PO2) that reflect variable levels of neuronal activity or local tissue hypoxia, pointing to the necessity of a functional brain oxygen sensor. This experimental animal (rats and mice) study shows that astrocytes, the most numerous brain glial cells, are sensitive to physiological changes in PO2. Astrocytes respond to decreases in PO2 a few millimeters of mercury below normal brain oxygenation with elevations in intracellular calcium ([Ca2+]i). The hypoxia sensor of astrocytes resides in the mitochondria in which oxygen is consumed. Physiological decrease in PO2 inhibits astroglial mitochondrial respiration, leading to mitochondrial depolarization, production of free radicals, lipid peroxidation, activation of phospholipase C, IP3 receptors, and release of Ca2+ from the intracellular stores. Hypoxia-induced [Ca2+]i increases in astrocytes trigger fusion of vesicular compartments containing ATP. Blockade of astrocytic signaling by overexpression of ATP-degrading enzymes or targeted astrocyte-specific expression of tetanus toxin light chain (to interfere with vesicular release mechanisms) within the brainstem respiratory rhythm-generating circuits reveals the fundamental physiological role of astroglial oxygen sensitivity; in low-oxygen conditions (environmental hypoxia), this mechanism increases breathing activity even in the absence of peripheral chemoreceptor oxygen sensing. These results demonstrate that astrocytes are functionally specialized CNS oxygen sensors tuned for rapid detection of physiological changes in brain oxygenation. SIGNIFICANCE STATEMENT Most, if not all, animal cells possess mechanisms that allow them to detect

  10. Functional Oxygen Sensitivity of Astrocytes.

    PubMed

    Angelova, Plamena R; Kasymov, Vitaliy; Christie, Isabel; Sheikhbahaei, Shahriar; Turovsky, Egor; Marina, Nephtali; Korsak, Alla; Zwicker, Jennifer; Teschemacher, Anja G; Ackland, Gareth L; Funk, Gregory D; Kasparov, Sergey; Abramov, Andrey Y; Gourine, Alexander V

    2015-07-22

    In terrestrial mammals, the oxygen storage capacity of the CNS is limited, and neuronal function is rapidly impaired if oxygen supply is interrupted even for a short period of time. However, oxygen tension monitored by the peripheral (arterial) chemoreceptors is not sensitive to regional CNS differences in partial pressure of oxygen (PO2 ) that reflect variable levels of neuronal activity or local tissue hypoxia, pointing to the necessity of a functional brain oxygen sensor. This experimental animal (rats and mice) study shows that astrocytes, the most numerous brain glial cells, are sensitive to physiological changes in PO2 . Astrocytes respond to decreases in PO2 a few millimeters of mercury below normal brain oxygenation with elevations in intracellular calcium ([Ca(2+)]i). The hypoxia sensor of astrocytes resides in the mitochondria in which oxygen is consumed. Physiological decrease in PO2 inhibits astroglial mitochondrial respiration, leading to mitochondrial depolarization, production of free radicals, lipid peroxidation, activation of phospholipase C, IP3 receptors, and release of Ca(2+) from the intracellular stores. Hypoxia-induced [Ca(2+)]i increases in astrocytes trigger fusion of vesicular compartments containing ATP. Blockade of astrocytic signaling by overexpression of ATP-degrading enzymes or targeted astrocyte-specific expression of tetanus toxin light chain (to interfere with vesicular release mechanisms) within the brainstem respiratory rhythm-generating circuits reveals the fundamental physiological role of astroglial oxygen sensitivity; in low-oxygen conditions (environmental hypoxia), this mechanism increases breathing activity even in the absence of peripheral chemoreceptor oxygen sensing. These results demonstrate that astrocytes are functionally specialized CNS oxygen sensors tuned for rapid detection of physiological changes in brain oxygenation. Significance statement: Most, if not all, animal cells possess mechanisms that allow them to

  11. Schopenhauer on Sense Perception and Aesthetic Cognition

    ERIC Educational Resources Information Center

    Vandenabeele, Bart

    2011-01-01

    Schopenhauer's account of sense perception contains an acute critique of Kant's theory of cognition. His analysis of the role of the understanding in perception may be closer to Kant's than he conceded, but his physiological analysis of the role of the senses nonetheless proffers a more plausible account than Kant's transcendental conception of…

  12. 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…

  13. Oxygen safety

    MedlinePlus

    ... Watch out for splattering grease. It can catch fire. Keep children with oxygen away from the stove top and oven. Cooking ... under the bed. Keep liquids that may catch fire away from your oxygen. This includes cleaning products that contain oil, grease, ...

  14. High Temperature Langasite SAW Oxygen Sensor

    SciTech Connect

    Zheng, Peng; Chin, Tao-Lun; Greve, David; Oppenheim, Irving; Malone, Vanessa; Cao, Limin

    2011-08-01

    High-temperature langasite SAW oxygen sensors using sputtered ZnO as a resistive gas-sensing layer were fabricated and tested. Sensitivity to oxygen gas was observed between 500°C to 700°C, with a sensitivity peak at about 625°C, consistent with the theoretical predictions of the acoustoelectric effect.

  15. Imaging of oxygen in microreactors and microfluidic systems

    NASA Astrophysics Data System (ADS)

    Sun, Shiwen; Ungerböck, Birgit; Mayr, Torsten

    2015-09-01

    This review gives an overview on the state-of-the-art of oxygen imaging in microfluidics. Oxygen imaging using optical oxygen sensors based on luminescence is a versatile and powerful tool for obtaining profoundly space-resolved information of oxygen in microreactors and microfluidic systems. We briefly introduce the principle of oxygen imaging and present techniques of oxygen imaging applied in microreactors and microfluidic devices, including selection criteria and demands of sensing material and basic set-up for a 2D oxygen sensing system. A detailed review of oxygen imaging in microreactors and microfluidic systems is given on different applications in oxygen gradient monitoring, cell culturing, single-cell analysis and chemical reactions. Finally, we discuss challenges and trends of oxygen imaging in microfluidic systems.

  16. Remote Sensing.

    ERIC Educational Resources Information Center

    Williams, Richard S., Jr.; Southworth, C. Scott

    1983-01-01

    The Landsat Program became the major event of 1982 in geological remote sensing with the successful launch of Landsat 4. Other 1982 remote sensing accomplishments, research, publications, (including a set of Landsat worldwide reference system index maps), and conferences are highlighted. (JN)

  17. Acute Bronchitis

    MedlinePlus

    Bronchitis is an inflammation of the bronchial tubes, the airways that carry air to your lungs. It ... chest tightness. There are two main types of bronchitis: acute and chronic. Most cases of acute bronchitis ...

  18. 30 CFR 57.8527 - Oxygen-deficiency testing.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Oxygen-deficiency testing. 57.8527 Section 57... Underground Only § 57.8527 Oxygen-deficiency testing. Flame safety lamps or other suitable devices shall be used to test for acute oxygen deficiency....

  19. 30 CFR 57.8527 - Oxygen-deficiency testing.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Oxygen-deficiency testing. 57.8527 Section 57... Underground Only § 57.8527 Oxygen-deficiency testing. Flame safety lamps or other suitable devices shall be used to test for acute oxygen deficiency....

  20. 30 CFR 57.8527 - Oxygen-deficiency testing.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Oxygen-deficiency testing. 57.8527 Section 57... Underground Only § 57.8527 Oxygen-deficiency testing. Flame safety lamps or other suitable devices shall be used to test for acute oxygen deficiency....

  1. 30 CFR 57.8527 - Oxygen-deficiency testing.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Oxygen-deficiency testing. 57.8527 Section 57... Underground Only § 57.8527 Oxygen-deficiency testing. Flame safety lamps or other suitable devices shall be used to test for acute oxygen deficiency....

  2. 30 CFR 57.8527 - Oxygen-deficiency testing.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Oxygen-deficiency testing. 57.8527 Section 57... Underground Only § 57.8527 Oxygen-deficiency testing. Flame safety lamps or other suitable devices shall be used to test for acute oxygen deficiency....

  3. Acute bronchial asthma.

    PubMed

    Grover, Sudhanshu; Jindal, Atul; Bansal, Arun; Singhi, Sunit C

    2011-11-01

    Acute asthma is the third commonest cause of pediatric emergency visits at PGIMER. Typically, it presents with acute onset respiratory distress and wheeze in a patient with past or family history of similar episodes. The severity of the acute episode of asthma is judged clinically and categorized as mild, moderate and severe. The initial therapy consists of oxygen, inhaled beta-2 agonists (salbutamol or terbutaline), inhaled budesonide (three doses over 1 h, at 20 min interval) in all and ipratropium bromide and systemic steroids (hydrocortisone or methylprednisolone) in acute severe asthma. Other causes of acute onset wheeze and breathing difficulty such as pneumonia, foreign body, cardiac failure etc. should be ruled out with help of chest radiography and appropriate laboratory investigations in first time wheezers and those not responding to 1 h of inhaled therapy. In case of inadequate response or worsening, intravenous infusion of magnesium sulphate, terbutaline or aminophylline may be used. Magnesium sulphate is the safest and most effective alternative among these. Severe cases may need ICU care and rarely, ventilatory support. PMID:21769523

  4. Oxygen Saturation Targeting and Bronchopulmonary Dysplasia.

    PubMed

    Darlow, Brian A; Morley, Colin J

    2015-12-01

    Oxygen saturation targeting is widely used in neonatal intensive care, but the optimal target range in very preterm infants has been uncertain and is the subject of recent debate and research. This review briefly discusses the technology of oxygen monitoring and the role of oxygen toxicity in preterm infants. The background to the recent trials of oxygen saturation targeting in acute and continuing care of very preterm infants is reviewed, and the findings and implications of the recent trials, particularly with respect to bronchopulmonary dysplasia, are discussed. PMID:26593080

  5. Henry's Law Activity of Oxygen in Molten Iron

    NASA Astrophysics Data System (ADS)

    Matousek, J. W.

    2015-09-01

    A model is proposed for the solubility of oxygen in molten iron in dilute solutions in which the oxygen exists in two states, free and associated. Only the free oxygen has thermodynamic activity in the sense of interaction with an electrochemical cell to produce the voltage described by the Nernst equation.

  6. Water Broadening of Oxygen

    NASA Astrophysics Data System (ADS)

    Drouin, Brian J.; Payne, Vivienne; Mlawer, Eli

    2013-06-01

    A need for precise air-mass retrievals utilizing the near-infrared O_2 A-band has motivated measurements of the water-broadening in oxygen. Experimental challenges have resulted in very little water broadened oxygen data, especially in the near-infrared where pressure broadened linewidth must compete with the relatively large thermal linewidth. Existing water broadening data^a for the O_2 A-band is of insufficient precision for application to the atmospheric data. Because of the nature of scattering processes, it is believed that broadening parameters for O_2 from one spectral region may be transferable to other spectral regions - so we investigated the O_2 60 GHz magnetic dipole Q branch which is also used prominently in remote sensing. Atmospheric retrievals of air-mass and temperature that use the 60 GHz magnetic dipole Q branch incorporate a water-broadening parameter that is scaled to self-broadened values, but there is only high temperature data that directly supports this hypothesis.^b We present precise O_2-H_2O broadening measurements for the magnetic dipole Q-branch and the pure-rotational band, measured at room temperature with a Zeeman-modulated absorption cell and a frequency-multiplier spectrometer. Here we will describe the apparatus and the measurement analysis. Inter-comparisons of these and other O_2 broadening data sets confirm the expectation of only minor band-to-band scaling of pressure broadening. The measurement provides a basis for fundamental parameterization of retrieval codes for the long-wavelength atmospheric measurements. Finally, we encourage the application of these measurements for retrievals of air-mass via remote sensing of the oxygen A-band. ^a E.M. Vess et al. J. Phys. Chem. A 116, 4069-4073 (2012). ^b G. Fanjoux et al. J. Chem. Phys. 101(2) 1061-1071 (1994).

  7. Oxygen-Concentrating Cell

    NASA Technical Reports Server (NTRS)

    Buehler, K.

    1986-01-01

    High-purity oxygen produced from breathing air or from propellantgrade oxygen in oxygen-concentrating cell. Operating economics of concentrator attractive: Energy consumption about 4 Wh per liter of oxygen, slightly lower than conventional electrochemical oxygen extractors.

  8. Using oxygen at home

    MedlinePlus

    ... DO NOT use oil-based products, such as petroleum jelly (Vaseline). Ask your oxygen equipment provider about ... oxygen; Hypoxia - home oxygen; Hospice - home oxygen References American Thoracic Society. Why do I need oxygen therapy? ...

  9. Acute nephritic syndrome

    MedlinePlus

    Glomerulonephritis - acute; Acute glomerulonephritis; Nephritis syndrome - acute ... Acute nephritic syndrome is often caused by an immune response triggered by an infection or other disease. Common causes ...

  10. Combinatorial Chemistry for Optical Sensing Applications

    NASA Astrophysics Data System (ADS)

    Díaz-García, M. E.; Luis, G. Pina; Rivero-Espejel, I. A.

    The recent interest in combinatorial chemistry for the synthesis of selective recognition materials for optical sensing applications is presented. The preparation, screening, and applications of libraries of ligands and chemosensors against molecular species and metal ions are first considered. Included in this chapter are also the developments involving applications of combinatorial approaches to the discovery of sol-gel and acrylic-based imprinted materials for optical sensing of antibiotics and pesticides, as well as libraries of doped sol-gels for high-throughput optical sensing of oxygen. The potential of combinatorial chemistry applied to the discovery of new sensing materials is highlighted.

  11. Acute sacroiliitis.

    PubMed

    Slobodin, Gleb; Rimar, Doron; Boulman, Nina; Kaly, Lisa; Rozenbaum, Michael; Rosner, Itzhak; Odeh, Majed

    2016-04-01

    The purpose of this study was to review the data on the etiology, risk factors, clinical presentations, and diagnosis of acute sacroiliitis. A Pubmed search utilizing the indexing term "acute sacroiliitis" was conducted and the data pertinent to the aim of the review was extracted and organized in accordance with the preplanned structure of the manuscript. The diagnosis of acute sacroiliitis is often challenging because of both the relative rarity of this presentation and diverse character of acute sacroiliac pain, frequently mimicking other, more prevalent disorders. Technetium bone scintigraphy can localize the disease process to the sacroiliac joint, while computed tomography or magnetic resonance imaging can be used for the detailed characterization and the extent of the disease as well as the diagnosis of complications. Pyogenic sacroiliitis is by far the most common cause of acute sacroiliitis. Brucellosis, acute sacroiliitis in the course of reactive arthritis, and crystalline-induced sacroiliitis frequently imitate pyogenic sacroiliitis. Acute sacroiliitis can rarely be also related to hematological malignancies or treatment with isotretinoin. Awareness to the possibility of acute sacroiliitis and a thorough physical examination are the necessary prerequisites to its timely diagnosis, while the appropriate laboratory and imaging studies should confirm the precise diagnosis and direct the appropriate treatment strategy. PMID:26847855

  12. Pervasive sensing

    NASA Astrophysics Data System (ADS)

    Nagel, David J.

    2000-11-01

    The coordinated exploitation of modern communication, micro- sensor and computer technologies makes it possible to give global reach to our senses. Web-cameras for vision, web- microphones for hearing and web-'noses' for smelling, plus the abilities to sense many factors we cannot ordinarily perceive, are either available or will be soon. Applications include (1) determination of weather and environmental conditions on dense grids or over large areas, (2) monitoring of energy usage in buildings, (3) sensing the condition of hardware in electrical power distribution and information systems, (4) improving process control and other manufacturing, (5) development of intelligent terrestrial, marine, aeronautical and space transportation systems, (6) managing the continuum of routine security monitoring, diverse crises and military actions, and (7) medicine, notably the monitoring of the physiology and living conditions of individuals. Some of the emerging capabilities, such as the ability to measure remotely the conditions inside of people in real time, raise interesting social concerns centered on privacy issues. Methods for sensor data fusion and designs for human-computer interfaces are both crucial for the full realization of the potential of pervasive sensing. Computer-generated virtual reality, augmented with real-time sensor data, should be an effective means for presenting information from distributed sensors.

  13. Numbers Sense

    ERIC Educational Resources Information Center

    Kathotia, Vinay

    2009-01-01

    This article reports on work undertaken by schools as part of Qualifications and Curriculum Authority's (QCA's) "Engaging mathematics for all learners" project. The goal was to use in the classroom, materials and approaches from a Royal Institution (Ri) Year 10 master-class, "Number Sense", which was inspired by examples from Michael Blastland and…

  14. Stable optical oxygen sensing materials based on click-coupling of fluorinated platinum(II) and palladium(II) porphyrins—A convenient way to eliminate dye migration and leaching

    PubMed Central

    Koren, Klaus; Borisov, Sergey M.; Klimant, Ingo

    2012-01-01

    Nucleophilic substitution of the labile para-fluorine atoms of 2,3,4,5,6-pentafluorophenyl groups enables a click-based covalent linkage of an oxygen indicator (platinum(II) or palladium(II) 5,10,15,20-meso-tetrakis-(2,3,4,5,6-pentafluorophenyl)-porphyrin) to the sensor matrix. Copolymers of styrene and pentafluorostyrene are chosen as polymeric materials. Depending on the reaction conditions either soluble sensor materials or cross-linked microparticles are obtained. Additionally, we prepared Ormosil-based sensors with linked indicator, which showed very high sensitivity toward oxygen. The effect of covalent coupling on sensor characteristics, stability and photophysical properties is studied. It is demonstrated that leaching and migration of the dye are eliminated in the new materials but excellent photophysical properties of the indicators are preserved. PMID:23576845

  15. Asthma in adults (acute)

    PubMed Central

    2011-01-01

    Introduction About 10% of adults have suffered an attack of asthma, and up to 5% of these have severe disease that responds poorly to treatment. Patients with severe disease have an increased risk of death, but patients with mild to moderate disease are also at risk of exacerbations. Most guidelines about the management of asthma follow stepwise protocols. This review does not endorse or follow any particular protocol, but presents the evidence about specific interventions. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical question: What are the effects of treatments for acute asthma? We searched: Medline, Embase, The Cochrane Library, and other important databases up to April 2010 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 100 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: beta2 agonists (plus ipratropium bromide, pressured metered-dose inhalers, short-acting continuous nebulised, short-acting intermittent nebulised, short-acting iv, and inhaled formoterol); corticosteroids (inhaled); corticosteroids (single oral, combined inhaled, and short courses); education about acute asthma; generalist care; helium–oxygen mixture (heliox); magnesium sulphate (iv and adding isotonic nebulised magnesium to inhaled beta2 agonists); mechanical ventilation; oxygen supplementation (controlled 28% oxygen and controlled 100% oxygen); and specialist care. PMID:21463536

  16. Acute Respiratory Distress Syndrome.

    PubMed

    Yadam, Suman; Bihler, Eric; Balaan, Marvin

    2016-01-01

    Acute respiratory distress syndrome (ARDS) is a serious inflammatory disorder with high mortality. Its main pathologic mechanism seems to result from increased alveolar permeability. Its definition has also changed since first being described according to the Berlin definition, which now classifies ARDS on a severity scale based on PaO2 (partial pressure of oxygen, arterial)/FIO2 (fraction of inspired oxygen) ratio. The cornerstone of therapy was found to be a low tidal volume strategy featuring volumes of 6 to 8 mL per kg of ideal body weight that has been shown to have decreased mortality as proven by the ARDSnet trials. There are other areas of treatment right now that include extracorporeal membrane oxygenation, as well for severe refractory hypoxemia. Other methods that include prone positioning for ventilation have also shown improvements in oxygenation. Positive end-expiratory pressure with lung recruitment maneuvers has also been found to be helpful. Other therapies that include vasodilators and neuromuscular agents are still being explored and need further studies to define their role in ARDS. PMID:26919679

  17. Acute malocclusion.

    PubMed

    Dupont, John S

    2006-01-01

    Acute malocclusion can result from disturbances in the maxillary/mandibular tooth relationship. These alterations in the occlusal position can result from high fillings, sinus problems, abscesses, periodontal disease, and moving or erupting teeth. Conditions seen less frequently include acute malocclusions secondary to an event (such as trauma) that make a stable dental relationship an unstable one. Patients can demonstrate any of a number of clinical conditions that interfere with their comfort and ability to function. This article provides information on some of the less familiar causes of acute malocclusion. PMID:16689064

  18. Monitoring oxygenation.

    PubMed

    Severinghaus, John W

    2011-06-01

    Cyanosis was used for a century after dentists began pulling teeth under 100% N(2)O in 1844 because brief (2 min) severe hypoxia is harmless. Deaths came with curare and potent anesthetic respiratory arrest. Leland Clark's invention of a polarographic blood oxygen tension electrode (1954) was introduced for transcutaneous PO2 monitoring to adjust PEEP and CPAP PO2 to prevent premature infant blindness from excess O2 (1972). Oximetry for warning military aviators was tried after WW II but not used for routine monitoring until Takuo Aoyagi (1973) discovered an equation to measure SaO2 by the ratio of ratios of red and IR light transmitted through tissue as it changed with arterial pulses. Pulse oximetry (1982) depended on simultaneous technology improvements of light emitting red and IR diodes, tiny cheap solid state sensors and micro-chip computers. Continuous monitoring of airway anesthetic concentration and oxygen also became very common after 1980. Death from anesthesia fell 10 fold between 1985 and 2000 as pulse oximetry became universally used, but no proof of a causative relationship to pulse oximetry exists. It is now assumed that all anesthesiologist became much more aware of the dangers of prolonged hypoxia, perhaps by using the pulse oximeters. PMID:21717228

  19. Adenosine A2a receptors and O2 sensing in development

    PubMed Central

    2011-01-01

    Reduced mitochondrial oxidative phosphorylation, via activation of adenylate kinase and the resulting exponential rise in the cellular AMP/ATP ratio, appears to be a critical factor underlying O2 sensing in many chemoreceptive tissues in mammals. The elevated AMP/ATP ratio, in turn, activates key enzymes that are involved in physiologic adjustments that tend to balance ATP supply and demand. An example is the conversion of AMP to adenosine via 5′-nucleotidase and the resulting activation of adenosine A2A receptors, which are involved in acute oxygen sensing by both carotid bodies and the brain. In fetal sheep, A2A receptors associated with carotid bodies trigger hypoxic cardiovascular chemoreflexes, while central A2A receptors mediate hypoxic inhibition of breathing and rapid eye movements. A2A receptors are also involved in hypoxic regulation of fetal endocrine systems, metabolism, and vascular tone. In developing lambs, A2A receptors play virtually no role in O2 sensing by the carotid bodies, but brain A2A receptors remain critically involved in the roll-off ventilatory response to hypoxia. In adult mammals, A2A receptors have been implicated in O2 sensing by carotid glomus cells, while central A2A receptors likely blunt hypoxic hyperventilation. In conclusion, A2A receptors are crucially involved in the transduction mechanisms of O2 sensing in fetal carotid bodies and brains. Postnatally, central A2A receptors remain key mediators of hypoxic respiratory depression, but they are less critical for O2 sensing in carotid chemoreceptors, particularly in developing lambs. PMID:21677265

  20. HORIZON SENSING

    SciTech Connect

    Larry G. Stolarczyk, Sc.D.

    2002-07-31

    Real-time horizon sensing (HS) on continuous mining (CM) machines is becoming an industry tool. Installation and testing of production-grade HS systems has been ongoing this quarter at Oxbow Mining Company, Monterey Coal Company (EXXON), FMC Trona, Twentymile Coal Company (RAG America), and SASOL Coal. Detailed monitoring of system function, user experience, and mining benefits is ongoing. All horizon sensor components have finished MSHA (United States) and IEC (International) certification.

  1. Conversational sensing

    NASA Astrophysics Data System (ADS)

    Preece, Alun; Gwilliams, Chris; Parizas, Christos; Pizzocaro, Diego; Bakdash, Jonathan Z.; Braines, Dave

    2014-05-01

    Recent developments in sensing technologies, mobile devices and context-aware user interfaces have made it pos- sible to represent information fusion and situational awareness for Intelligence, Surveillance and Reconnaissance (ISR) activities as a conversational process among actors at or near the tactical edges of a network. Motivated by use cases in the domain of Company Intelligence Support Team (CoIST) tasks, this paper presents an approach to information collection, fusion and sense-making based on the use of natural language (NL) and controlled nat- ural language (CNL) to support richer forms of human-machine interaction. The approach uses a conversational protocol to facilitate a ow of collaborative messages from NL to CNL and back again in support of interactions such as: turning eyewitness reports from human observers into actionable information (from both soldier and civilian sources); fusing information from humans and physical sensors (with associated quality metadata); and assisting human analysts to make the best use of available sensing assets in an area of interest (governed by man- agement and security policies). CNL is used as a common formal knowledge representation for both machine and human agents to support reasoning, semantic information fusion and generation of rationale for inferences, in ways that remain transparent to human users. Examples are provided of various alternative styles for user feedback, including NL, CNL and graphical feedback. A pilot experiment with human subjects shows that a prototype conversational agent is able to gather usable CNL information from untrained human subjects.

  2. Acute Bronchitis

    MedlinePlus

    ... bronchitis? Acute bronchitis is almost always caused by viruses that attack the lining of the bronchial tree ... infection. As your body fights back against these viruses, more swelling occurs and more mucus is produced. ...

  3. Acute Pericarditis

    MedlinePlus

    ... large pericardial effusions). Acute pericarditis usually responds to colchicine or NSAIDs (such as aspirin and ibuprofen ) taken ... reduce pain but relieves it by reducing inflammation. Colchicine also decreases the chance of pericarditis returning later. ...

  4. Acute silicosis with bilateral pneumothorax.

    PubMed

    Srivastava, G N; Prasad, Rajniti; Meena, Manoj; Hussain, Moosa

    2014-01-01

    We present a case of acute silicosis with bilateral pneumothorax of a 28-year-old man working at a stone crusher factory for 1 year. He presented to the emergency department with cough, respiratory distress and diffuse chest pain. The patient was managed with bilateral intercostal tube drainage under water seal, oxygen inhalation and conservative therapy. On follow-up he showed improvement of resting dyspnoea and was doing well. This case is being reported because of the rare complications of acute silicosis as bilateral pneumothorax. PMID:24862410

  5. Acute silicosis with bilateral pneumothorax

    PubMed Central

    Srivastava, G N; Prasad, Rajniti; Meena, Manoj; Hussain, Moosa

    2014-01-01

    We present a case of acute silicosis with bilateral pneumothorax of a 28-year-old man working at a stone crusher factory for 1 year. He presented to the emergency department with cough, respiratory distress and diffuse chest pain. The patient was managed with bilateral intercostal tube drainage under water seal, oxygen inhalation and conservative therapy. On follow-up he showed improvement of resting dyspnoea and was doing well. This case is being reported because of the rare complications of acute silicosis as bilateral pneumothorax. PMID:24862410

  6. Oxygen, Gastrin-Releasing Peptide, and Pediatric Lung Disease: Life in the Balance

    PubMed Central

    Sunday, Mary E.

    2014-01-01

    Excessive oxygen (O2) can cause tissue injury, scarring, aging, and even death. Our laboratory is studying O2-sensing pulmonary neuroendocrine cells (PNECs) and the PNEC-derived product gastrin-releasing peptide (GRP). Reactive oxygen species (ROS) generated from exposure to hyperoxia, ozone, or ionizing radiation (RT) can induce PNEC degranulation and GRP secretion. PNEC degranulation is also induced by hypoxia, and effects of hypoxia are mediated by free radicals. We have determined that excessive GRP leads to lung injury with acute and chronic inflammation, leading to pulmonary fibrosis (PF), triggered via ROS exposure or by directly treating mice with exogenous GRP. In animal models, GRP-blockade abrogates lung injury, inflammation, and fibrosis. The optimal time frame for GRP-blockade and the key target cell types remain to be determined. The concept of GRP as a mediator of ROS-induced tissue damage represents a paradigm shift about how O2 can cause injury, inflammation, and fibrosis. The host PNEC response in vivo may depend on individual ROS sensing mechanisms and subsequent GRP secretion. Ongoing scientific and clinical investigations promise to further clarify the molecular pathways and clinical relevance of GRP in the pathogenesis of diverse pediatric lung diseases. PMID:25101250

  7. CONFERENCE ON MTBE AND OTHER OXYGENATES

    EPA Science Inventory

    After reports of acute health symptoms (e.g., headache, nausea, eye irritation) arose following the introduction of oxygenated gasoline in Alaska and some other locales in late 1992, EPA, the Centers for Disease Control and Prevention, academic institutions, and other organizatio...

  8. HORIZON SENSING

    SciTech Connect

    Larry G. Stolarczyk

    2003-03-18

    With the aid of a DOE grant (No. DE-FC26-01NT41050), Stolar Research Corporation (Stolar) developed the Horizon Sensor (HS) to distinguish between the different layers of a coal seam. Mounted on mining machine cutter drums, HS units can detect or sense the horizon between the coal seam and the roof and floor rock, providing the opportunity to accurately mine the section of the seam most desired. HS also enables accurate cutting of minimum height if that is the operator's objective. Often when cutting is done out-of-seam, the head-positioning function facilitates a fixed mining height to minimize dilution. With this technology, miners can still be at a remote location, yet cut only the clean coal, resulting in a much more efficient overall process. The objectives of this project were to demonstrate the feasibility of horizon sensing on mining machines and demonstrate that Horizon Sensing can allow coal to be cut cleaner and more efficiently. Stolar's primary goal was to develop the Horizon Sensor (HS) into an enabling technology for full or partial automation or ''agile mining''. This technical innovation (R&D 100 Award Winner) is quickly demonstrating improvements in productivity and miner safety at several prominent coal mines in the United States. In addition, the HS system can enable the cutting of cleaner coal. Stolar has driven the HS program on the philosophy that cutting cleaner coal means burning cleaner coal. The sensor, located inches from the cutting bits, is based upon the physics principles of a Resonant Microstrip Patch Antenna (RMPA). When it is in proximity of the rock-coal interface, the RMPA impedance varies depending on the thickness of uncut coal. The impedance is measured by the computer-controlled electronics and then sent by radio waves to the mining machine. The worker at the machine can read the data via a Graphical User Interface, displaying a color-coded image of the coal being cut, and direct the machine appropriately. The Horizon Sensor

  9. Acute myelogenous leukemia (AML) - children

    MedlinePlus

    Acute myelogenous leukemia - children; AML; Acute myeloid leukemia - children; Acute granulocytic leukemia - children; Acute myeloblastic leukemia - children; Acute non-lymphocytic leukemia (ANLL) - children

  10. NO.sub.x sensing devices having conductive oxide electrodes

    SciTech Connect

    Montgomery, Frederick C.; West, David L.; Armstrong, Timothy R.; Maxey, Lonnie C.

    2010-03-16

    A NO.sub.x sensing device includes at least one pair of spaced electrodes, at least one of which is made of a conductive oxide, and an oxygen-ion conducting material in bridging electrical communication with the electrodes.

  11. Successful Management of a Patient with Refractory Ventricular Fibrillation (VF) due to Acute Myocardial Infarction (AMI) and Lung Injury by Transition from Percutaneous Cardiopulmonary Support (PCPS) to Veno-Venous Extracorporeal Membrane Oxygenation (ECMO).

    PubMed

    Sato, Atsushi; Isoda, Kikuo; Gatate, Yodo; Akita, Koji; Daida, Hiroyuki

    2016-01-01

    A 69-year-old man was admitted to our hospital with cardiopulmonary arrest. Percutaneous cardio-pulmonary support (PCPS) using the right femoral artery and vein was initiated, because ventricular fibrillation continued. Although we succeeded in defibrillation after percutaneous coronary intervention (PCI), a chest radiograph indicated a pneumothorax in the right lung and a pulmonic contusion in the left lung caused by cardiopulmonary resuscitation. Two days after PCI, partial pressure of arterial oxygen (PaO2) from the right radial artery suddenly decreased, and his cardiac function showed improvement on an echocardiogram. To avoid additional brain damage, we converted the treatment to veno-venous extracorporeal membrane oxygenation by changing the blood returning site of PCPS from the right femoral artery to the right jugular vein. Thereafter, the patient's PaO2 level gradually improved. PMID:27432096

  12. Surface Acoustic Wave Devices for Harsh Environment Wireless Sensing

    PubMed Central

    Greve, David W.; Chin, Tao-Lun; Zheng, Peng; Ohodnicki, Paul; Baltrus, John; Oppenheim, Irving J.

    2013-01-01

    Langasite surface acoustic wave devices can be used to implement harsh-environment wireless sensing of gas concentration and temperature. This paper reviews prior work on the development of langasite surface acoustic wave devices, followed by a report of recent progress toward the implementation of oxygen gas sensors. Resistive metal oxide films can be used as the oxygen sensing film, although development of an adherent barrier layer will be necessary with the sensing layers studied here to prevent interaction with the langasite substrate. Experimental results are presented for the performance of a langasite surface acoustic wave oxygen sensor with tin oxide sensing layer, and these experimental results are correlated with direct measurements of the sensing layer resistivity. PMID:23708273

  13. Surface acoustic wave devices for harsh environment wireless sensing

    SciTech Connect

    Greve, David W.; Chin, Tao -Lun; Zheng, Peng; Ohodnicki, Paul; Baltrus, John; Oppenheim, Irving J.

    2013-05-24

    In this study, langasite surface acoustic wave devices can be used to implement harsh environment wireless sensing of gas concentration and temperature. This paper reviews prior work on the development of langasite surface acoustic wave devices, followed by a report of recent progress toward the implementation of oxygen gas sensors. Resistive metal oxide films can be used as the oxygen sensing film, although development of an adherent barrier layer will be necessary with the sensing layers studied here to prevent interaction with the langasite substrate. Experimental results are presented for the performance of a langasite surface acoustic wave oxygen sensor with tin oxide sensing layer, and these experimental results are correlated with direct measurements of the sensing layer resistivity.

  14. Surface acoustic wave devices for harsh environment wireless sensing

    DOE PAGESBeta

    Greve, David W.; Chin, Tao -Lun; Zheng, Peng; Ohodnicki, Paul; Baltrus, John; Oppenheim, Irving J.

    2013-05-24

    In this study, langasite surface acoustic wave devices can be used to implement harsh environment wireless sensing of gas concentration and temperature. This paper reviews prior work on the development of langasite surface acoustic wave devices, followed by a report of recent progress toward the implementation of oxygen gas sensors. Resistive metal oxide films can be used as the oxygen sensing film, although development of an adherent barrier layer will be necessary with the sensing layers studied here to prevent interaction with the langasite substrate. Experimental results are presented for the performance of a langasite surface acoustic wave oxygen sensormore » with tin oxide sensing layer, and these experimental results are correlated with direct measurements of the sensing layer resistivity.« less

  15. Hyperbaric oxygen therapy. Promoting healing in difficult cases

    SciTech Connect

    Cohn, G.H.

    1986-02-01

    Inhalation of pressurized 100% oxygen is a helpful adjunctive treatment for certain patients, because the increased oxygen carried by the blood to the tissue enhances new growth of microcirculation and, thus, healing. Patients with tissue breakdown after radiation therapy, refractory osteomyelitis, gas gangrene, soft-tissue infection with necrosis from mixed aerobic and anaerobic organisms, crush injuries resulting in acute ischemia, and compromised skin grafts or non-healing wounds are likely to benefit from hyperbaric oxygen therapy.

  16. Acute Pneumonia.

    PubMed

    Arshad, Hammad; Fasanya, Adebayo; Cheema, Tariq; Singh, Anil C

    2016-01-01

    Acute pneumonia is an active infection of the lungs that results when an individual at risk gets exposed to a particular microbiological pathogen. Acute pneumonia is the leading cause of death in the United States that is attributable to an infection. The risk factors, pathogenesis, and microbiological organisms involved differ if the pneumonia develops in the community versus health care-associated environment. The development of concise and comprehensive guidelines has led to an improvement in the management of the problem. However, the emergence of multidrug-resistant organisms and the increase in the percentage of elderly population keep mortality risk very substantial. PMID:26919676

  17. Infrastructure sensing.

    PubMed

    Soga, Kenichi; Schooling, Jennifer

    2016-08-01

    Design, construction, maintenance and upgrading of civil engineering infrastructure requires fresh thinking to minimize use of materials, energy and labour. This can only be achieved by understanding the performance of the infrastructure, both during its construction and throughout its design life, through innovative monitoring. Advances in sensor systems offer intriguing possibilities to radically alter methods of condition assessment and monitoring of infrastructure. In this paper, it is hypothesized that the future of infrastructure relies on smarter information; the rich information obtained from embedded sensors within infrastructure will act as a catalyst for new design, construction, operation and maintenance processes for integrated infrastructure systems linked directly with user behaviour patterns. Some examples of emerging sensor technologies for infrastructure sensing are given. They include distributed fibre-optics sensors, computer vision, wireless sensor networks, low-power micro-electromechanical systems, energy harvesting and citizens as sensors. PMID:27499845

  18. Remote Sensing

    NASA Technical Reports Server (NTRS)

    Rickman, Douglas

    2008-01-01

    Remote sensing is measuring something without touching it. Most methods measure a portion of the electro-magnetic spectrum using energy reflected from or emitted by a material. Moving the instrument away makes it easier to see more at one time. Airplanes are good but satellites are much better. Many things can not be easily measured on the scale of an individual person. Example - measuring all the vegetation growing at one time in even the smallest country. A satellite can see things over large areas repeatedly and in a consistent way. Data from the detector is reported as digital values for a grid that covers some portion of the Earth. Because it is digital and consistent a computer can extract information or enhance the data for a specific purpose.

  19. Acute Pancreatitis

    PubMed Central

    Geokas, Michael C.

    1972-01-01

    For many decades two types of acute pancreatitis have been recognized: the edematous or interstitial and the hemorrhagic or necrotic. In most cases acute pancreatitis is associated with alcoholism or biliary tract disease. Elevated serum or urinary α-amylase is the most important finding in diagnosis. The presence of methemalbumin in serum and in peritoneal or pleural fluid supports the diagnosis of the hemorrhagic form of the disease in patients with a history and enzyme studies suggestive of pancreatitis. There is no characteristic clinical picture in acute pancreatitis, and its complications are legion. Pancreatic pseudocyst is probably the most common and pancreatic abscess is the most serious complication. The pathogenetic principle is autodigestion, but the precise sequence of biochemical events is unclear, especially the mode of trypsinogen activation and the role of lysosomal hydrolases. A host of metabolic derangements have been identified in acute pancreatitis, involving lipid, glucose, calcium and magnesium metabolism and changes of the blood clotting mechanism, to name but a few. Medical treatment includes intestinal decompression, analgesics, correction of hypovolemia and other supportive and protective measures. Surgical exploration is advisable in selected cases, when the diagnosis is in doubt, and is considered imperative in the presence of certain complications, especially pancreatic abscess. PMID:4559467

  20. Living with Oxygen Therapy

    MedlinePlus

    ... page from the NHLBI on Twitter. Living With Oxygen Therapy Oxygen therapy helps many people function better and be ... chronic obstructive pulmonary disease) Although you may need oxygen therapy continuously or for long periods, it doesn' ...

  1. Hyperbaric oxygen therapy

    MedlinePlus

    Hyperbaric oxygen therapy uses a special pressure chamber to increase the amount of oxygen in the blood. ... outpatient centers. The air pressure inside a hyperbaric oxygen chamber is about two and a half times ...

  2. 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. PMID:23317164

  3. Fully Enzymatic Membraneless Glucose|Oxygen Fuel Cell That Provides 0.275 mA cm(-2) in 5 mM Glucose, Operates in Human Physiological Solutions, and Powers Transmission of Sensing Data.

    PubMed

    Ó Conghaile, Peter; Falk, Magnus; MacAodha, Domhnall; Yakovleva, Maria E; Gonaus, Christoph; Peterbauer, Clemens K; Gorton, Lo; Shleev, Sergey; Leech, Dónal

    2016-02-16

    Coimmobilization of pyranose dehydrogenase as an enzyme catalyst, osmium redox polymers [Os(4,4'-dimethoxy-2,2'-bipyridine)2(poly(vinylimidazole))10Cl](+) or [Os(4,4'-dimethyl-2,2'-bipyridine)2(poly(vinylimidazole))10Cl](+) as mediators, and carbon nanotube conductive scaffolds in films on graphite electrodes provides enzyme electrodes for glucose oxidation. The recombinant enzyme and a deglycosylated form, both expressed in Pichia pastoris, are investigated and compared as biocatalysts for glucose oxidation using flow injection amperometry and voltammetry. In the presence of 5 mM glucose in phosphate-buffered saline (PBS) (50 mM phosphate buffer solution, pH 7.4, with 150 mM NaCl), higher glucose oxidation current densities, 0.41 mA cm(-2), are obtained from enzyme electrodes containing the deglycosylated form of the enzyme. The optimized glucose-oxidizing anode, prepared using deglycosylated enzyme coimmobilized with [Os(4,4'-dimethyl-2,2'-bipyridine)2(poly(vinylimidazole))10Cl](+) and carbon nanotubes, was coupled with an oxygen-reducing bilirubin oxidase on gold nanoparticle dispersed on gold electrode as a biocathode to provide a membraneless fully enzymatic fuel cell. A maximum power density of 275 μW cm(-2) is obtained in 5 mM glucose in PBS, the highest to date under these conditions, providing sufficient power to enable wireless transmission of a signal to a data logger. When tested in whole human blood and unstimulated human saliva maximum power densities of 73 and 6 μW cm(-2) are obtained for the same fuel cell configuration, respectively. PMID:26750758

  4. Mutations in N-terminal Flanking Region of Blue Light-sensing Light-Oxygen and Voltage 2 (LOV2) Domain Disrupt Its Repressive Activity on Kinase Domain in the Chlamydomonas Phototropin*

    PubMed Central

    Aihara, Yusuke; Yamamoto, Takaharu; Okajima, Koji; Yamamoto, Kazuhiko; Suzuki, Tomomi; Tokutomi, Satoru; Tanaka, Kazuma; Nagatani, Akira

    2012-01-01

    Phototropin is a light-regulated kinase that mediates a variety of photoresponses such as phototropism, chloroplast positioning, and stomata opening in plants to increase the photosynthetic efficiency. Blue light stimulus first induces local conformational changes in the chromophore-bearing light-oxygen and voltage 2 (LOV2) domain of phototropin, which in turn activates the serine/threonine (Ser/Thr) kinase domain in the C terminus. To examine the kinase activity of full-length phototropin conventionally, we employed the budding yeast Saccharomyces cerevisiae. In this organism, Ser/Thr kinases (Fpk1p and Fpk2p) that show high sequence similarity to the kinase domain of phototropins exist. First, we demonstrated that the phototropin from Chlamydomonas reinhardtii (CrPHOT) could complement loss of Fpk1p and Fpk2p to allow cell growth in yeast. Furthermore, this reaction was blue light-dependent, indicating that CrPHOT was indeed light-activated in yeast cells. We applied this system to a large scale screening for amino acid substitutions in CrPHOT that elevated the kinase activity in darkness. Consequently, we identified a cluster of mutations located in the N-terminal flanking region of LOV2 (R199C, L202L, D203N/G/V, L204P, T207I, and R210H). An in vitro phosphorylation assay confirmed that these mutations substantially reduced the repressive activity of LOV2 on the kinase domain in darkness. Furthermore, biochemical analyses of the representative T207I mutant demonstrated that the mutation affected neither spectral nor multimerization properties of CrPHOT. Hence, the N-terminal flanking region of LOV2, as is the case with the C-terminal flanking Jα region, appears to play a crucial role in the regulation of kinase activity in phototropin. PMID:22291022

  5. One-pot green synthesis of high quantum yield oxygen-doped, nitrogen-rich, photoluminescent polymer carbon nanoribbons as an effective fluorescent sensing platform for sensitive and selective detection of silver(I) and mercury(II) ions.

    PubMed

    Wang, Zhong-Xia; Ding, Shou-Nian

    2014-08-01

    This work reports on a facile, economical, and green preparative strategy toward water-soluble, fluorescent oxygen-doped, nitrogen-rich, photoluminescent polymer carbon nanoribbons (ONPCRs) with a quantum yield of approximately 25.61% by the hydrothermal process using uric acid as a carbon-nitrogen source for the first time. The as-prepared fluorescent ONPCRs showed paddy leaf-like structure with 80-160 nm length and highly efficient fluorescent quenching ability in the presence of mercury(II) (Hg(2+)) or silver (Ag(+)) ions due to the formed nonfluorescent metal complexes via robust Hg(2+)-O or Ag(+)-N interaction with the O and N of fluorescent ONPCRs, which allowed the analysis of Hg(2+) and Ag(+) ions in a very simple method. By employing this sensor, excellent linear relationships existed between the quenching degree of the ONPCRs and the concentrations of Hg(2+) and Ag(+) ions in the range of 2.0 nM to 60 μM and 5.0 nM to 80 μM, respectively. By using ethylenediaminetetraacetate and ammonia as the masking agent of Hg(2+) and Ag(+) ions, respectively, Hg(2+) or Ag(+) ions were exclusively detected in coexistence with Ag(+) or Hg(2+) ions with high sensitivity, and the detection limits as low as 0.68 and 1.73 nM (3σ) were achieved, respectively, which also provided a reusable detection method for Hg(2+) and Ag(+) ions. Therefore, the easily synthesized fluorescent ONPCRs may have great potential applications in the detection of Hg(2+) and Ag(+) ions for biological assay and environmental protection. PMID:24979236

  6. [Effect of aktovegin on dynamics of the oxygen methabolism in tissues].

    PubMed

    Pavlov, O O

    2009-01-01

    The analysis of aktovegin impact on methabolism dynamics of oxygen in tissues was performed. Indirect impact of aktovegin on the oxygen cascade dynamics is provided through the mechanism of the erythrocytes saturation by oxygen. The efficacy of aktovegin application as antihypoxic preparation in patients with an acute gastric strees-affection was proved. PMID:19670751

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

    NASA Technical Reports Server (NTRS)

    Kelly, Mark; Pettit, Donald

    2003-01-01

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

  8. Bronchitis - acute

    MedlinePlus

    ... or be more short of breath. Exams and Tests Your health care provider will listen to the breathing sounds in ... Tests may include: Chest x-ray , if your health care provider suspects pneumonia Pulse oximetry, a painless test that helps determine the amount of oxygen in ...

  9. Bimodular high temperature planar oxygen gas sensor.

    PubMed

    Sun, Xiangcheng; Liu, Yixin; Gao, Haiyong; Gao, Pu-Xian; Lei, Yu

    2014-01-01

    A bimodular planar O2 sensor was fabricated using NiO nanoparticles (NPs) thin film coated yttria-stabilized zirconia (YSZ) substrate. The thin film was prepared by radio frequency (r.f.) magnetron sputtering of NiO on YSZ substrate, followed by high temperature sintering. The surface morphology of NiO NPs film was characterized by atomic force microscope (AFM) and scanning electron microscope (SEM). X-ray diffraction (XRD) patterns of NiO NPs thin film before and after high temperature O2 sensing demonstrated that the sensing material possesses a good chemical and structure stability. The oxygen detection experiments were performed at 500, 600, and 800°C using the as-prepared bimodular O2 sensor under both potentiometric and resistance modules. For the potentiometric module, a linear relationship between electromotive force (EMF) output of the sensor and the logarithm of O2 concentration was observed at each operating temperature, following the Nernst law. For the resistance module, the logarithm of electrical conductivity was proportional to the logarithm of oxygen concentration at each operating temperature, in good agreement with literature report. In addition, this bimodular sensor shows sensitive, reproducible and reversible response to oxygen under both sensing modules. Integration of two sensing modules into one sensor could greatly enrich the information output and would open a new venue in the development of high temperature gas sensors. PMID:25191652

  10. Bimodular high temperature planar oxygen gas sensor

    PubMed Central

    Sun, Xiangcheng; Liu, Yixin; Gao, Haiyong; Gao, Pu-Xian; Lei, Yu

    2014-01-01

    A bimodular planar O2 sensor was fabricated using NiO nanoparticles (NPs) thin film coated yttria-stabilized zirconia (YSZ) substrate. The thin film was prepared by radio frequency (r.f.) magnetron sputtering of NiO on YSZ substrate, followed by high temperature sintering. The surface morphology of NiO NPs film was characterized by atomic force microscope (AFM) and scanning electron microscope (SEM). X-ray diffraction (XRD) patterns of NiO NPs thin film before and after high temperature O2 sensing demonstrated that the sensing material possesses a good chemical and structure stability. The oxygen detection experiments were performed at 500, 600, and 800°C using the as-prepared bimodular O2 sensor under both potentiometric and resistance modules. For the potentiometric module, a linear relationship between electromotive force (EMF) output of the sensor and the logarithm of O2 concentration was observed at each operating temperature, following the Nernst law. For the resistance module, the logarithm of electrical conductivity was proportional to the logarithm of oxygen concentration at each operating temperature, in good agreement with literature report. In addition, this bimodular sensor shows sensitive, reproducible and reversible response to oxygen under both sensing modules. Integration of two sensing modules into one sensor could greatly enrich the information output and would open a new venue in the development of high temperature gas sensors. PMID:25191652

  11. Acute diarrhea.

    PubMed

    Barr, Wendy; Smith, Andrew

    2014-02-01

    Acute diarrhea in adults is a common problem encountered by family physicians. The most common etiology is viral gastroenteritis, a self-limited disease. Increases in travel, comorbidities, and foodborne illness lead to more bacteria-related cases of acute diarrhea. A history and physical examination evaluating for risk factors and signs of inflammatory diarrhea and/or severe dehydration can direct any needed testing and treatment. Most patients do not require laboratory workup, and routine stool cultures are not recommended. Treatment focuses on preventing and treating dehydration. Diagnostic investigation should be reserved for patients with severe dehydration or illness, persistent fever, bloody stool, or immunosuppression, and for cases of suspected nosocomial infection or outbreak. Oral rehydration therapy with early refeeding is the preferred treatment for dehydration. Antimotility agents should be avoided in patients with bloody diarrhea, but loperamide/simethicone may improve symptoms in patients with watery diarrhea. Probiotic use may shorten the duration of illness. When used appropriately, antibiotics are effective in the treatment of shigellosis, campylobacteriosis, Clostridium difficile, traveler's diarrhea, and protozoal infections. Prevention of acute diarrhea is promoted through adequate hand washing, safe food preparation, access to clean water, and vaccinations. PMID:24506120

  12. Sinusitis (acute)

    PubMed Central

    2008-01-01

    Introduction Acute sinusitis is defined pathologically, by transient inflammation of the mucosal lining of the paranasal sinuses lasting less than 4 weeks. Clinically, it is characterised by nasal congestion, rhinorrhoea, facial pain, hyposmia, sneezing, and, if more severe, additional malaise and fever. It affects 1−5% of the adult population each year in Europe. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of treatments in people with clinically diagnosed acute sinusitis, and with radiologically or bacteriologically confirmed acute sinusitis? We searched: Medline, Embase, The Cochrane Library and other important databases up to August 2007 (BMJ Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 19 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: antibiotics (amoxicillin, co-amoxiclav, doxycycline, cephalosporins, macrolides, different doses [amoxicillin, co-amoxiclav, doxycycline, cephalosporins, macrolides], long-course regimens), antihistamines, cephalosporins or macrolides, decongestants (xylometazoline, phenylephrine, pseudoephedrine), doxycycline, saline nasal washes, steam inhalation, and topical corticosteroids (intra-nasal). PMID:19450327

  13. Sinusitis (acute)

    PubMed Central

    2011-01-01

    Introduction Acute sinusitis is defined pathologically, by transient inflammation of the mucosal lining of the paranasal sinuses lasting less than 4 weeks. Clinically, it is characterised by nasal congestion, rhinorrhoea, facial pain, hyposmia, sneezing, and, if more severe, additional malaise and fever. It affects 1% to 5% of the adult population each year in Europe. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of treatments in people with clinically diagnosed acute sinusitis, and in people with radiologically or bacteriologically confirmed acute sinusitis? We searched: Medline, Embase, The Cochrane Library, and other important databases up to June 2011 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 19 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: antibiotics (amoxicillin, amoxicillin–clavulanic acid [co-amoxiclav], doxycycline, cephalosporins, macrolides; different doses, long-course regimens), antihistamines, decongestants (xylometazoline, phenylephrine, pseudoephedrine), saline nasal washes, steam inhalation, and topical corticosteroids (intranasal). PMID:22189346

  14. Acute glomerulonephritis.

    PubMed

    Yoshizawa, N

    2000-09-01

    Acute glomerulonephritis (AGN) is a representative disease of acute nephritic syndrome characterized by the sudden appearance of edema, hematuria, proteinuria, and hypertension. The prototype of AGN is acute poststreptococcal glomerulonephritis (APSGN). "Nephritogenic streptococci" are defined as organisms that are cultured from a patient who develops AGN. Although only a limited number of M-types of streptococci have been recognized as "nephritogenic streptococci", all M-types of streptococci may have nephritogenic potential because the genes for major putative nephritogenic antigens such as SPEB and NAPIr are found to be present in all group A streptococci thus far examined. Pathogenic mechanisms for APSGN involving both humoral and cell-mediated immunity have been recently proposed. The role of humoral immunity is presumed to be mediated by the in situ formation of nephritogenic streptococcal antigen-antibody complexes and circulating immune complexes. While in the cellular immune component a role for delayed-type hypersensitivity has been suggested to contribute to the pathogenesis of APSGN. PMID:10969898

  15. Artificial oxygen transport protein

    SciTech Connect

    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.

  16. Aquatic Respiration Rate Measurements at Low Oxygen Concentrations

    PubMed Central

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

    2014-01-01

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

  17. [Thematic Issue: Remote Sensing.

    ERIC Educational Resources Information Center

    Howkins, John, Ed.

    1978-01-01

    Four of the articles in this publication discuss the remote sensing of the Earth and its resources by satellites. Among the topics dealt with are the development and management of remote sensing systems, types of satellites used for remote sensing, the uses of remote sensing, and issues involved in using information obtained through remote…

  18. Clinical use of the hyperbaric oxygen bed

    PubMed Central

    Ashfield, R.; Drew, C. E.

    1969-01-01

    The Vickers hyperbaric oxygen bed is described and details of its use are given in the treatment of 207 patients with a wide variety of clinical conditions. As part of a deliberate policy, a special study was made of its place in the treatment of severe acute myocardial infarction. No major procedural difficulties were encountered. Results are generally encouraging and frequently of dramatic benefit. ImagesFig. 1 PMID:5358379

  19. Electrochemical Sensing for a Rapidly Evolving World

    NASA Astrophysics Data System (ADS)

    Mullen, Max Robertson

    This dissertation focuses on three projects involving the development of harsh environment gas sensors. The first project discusses the development of a multipurpose oxygen sensor electrode for use in sealing with the common electrolyte yttria stabilized zirconia. The purpose of the sealing function is to produce an internal reference environment maintained by a metal/metal oxide mixture, a criteria for miniaturization of potentiometric oxygen sensing technology. This sensor measures a potential between the internal reference and a sensing environment. The second project discusses the miniaturization of an oxygen sensor and the fabrication of a more generalized electrochemical sensing platform. The third project discusses the discovery of a new mechanism in the electrochemical sensing of ammonia through molecular recognition and the utilization of a sensor taking advantage of the new mechanism. An initial study involving the development of a microwave synthesized La0.8Sr0.2Al0.9Mn0.1O3 sensor electrode material illustrates the ability of the material developed to meet ionic and electronic conducting requirements for effective and Nernstian oxygen sensing. In addition the material deforms plastically under hot isostatic pressing conditions in a similar temperature and pressure regime with yttria stabilized zirconia to produce a seal and survive temperatures up to 1350 °C. In the second project we show novel methods to seal an oxygen environment inside a device cavity to produce an electrochemical sensor body using room temperature plasma-activated bonding and low temperature and pressure assisted plasma-activated bonding with silicon bodies, both in a clean room environment. The evolution from isostatic hot pressing methods towards room temperature complementary metal oxide semiconductor (CMOS) compatible technologies using single crystal silicon substrates in the clean room allows the sealing of devices on a much larger scale. Through this evolution in bonding

  20. Electrochemical Oxygen Sensor Development for Liquid Sodium

    NASA Astrophysics Data System (ADS)

    Nollet, Billy K.

    Safe operation of a sodium-cooled fast reactor (SFR) requires in-depth understanding of the corrosion implications of liquid sodium coolant on reactor materials. Dissolved oxygen concentration is of particular importance in characterizing sodium attack, so an accurate means of measuring and controlling oxygen is crucial. There is significant room for improvement in current oxygen sensing technology, so extensive research has been conducted at the University of Wisconsin-Madison to address this issue. Experimental facilities and electrochemical oxygen sensors have been developed, tested, and analyzed. This research is discussed in detail in this report. The oxygen sensors tested in this research were developed using a yttria stabilized zirconia (YSZ) electrolyte whereas many of the past research in this field was conducted with yttria doped thoria (YDT or YST) electrolytes. Thorium, an alpha emitter, is expensive and increasingly difficult to acquire, so motivation to switch to a new material exists. YSZ is commonly used as the electrolyte for solid oxide fuel cells, and ample data is available for high temperature ionic conduction of this material. While some work has been done with YSZ in oxygen sensors (the automotive field, for example, uses YSZ O2 sensors), research on YSZ sensors in sodium is limited. A thorough study of YSZ-based electrochemical oxygen sensors must include detailed corrosion testing and analysis of YSZ in liquid sodium, careful oxygen sensor development and testing, and finally, a comprehensive analysis of the acquired sensor data. The research presented in this report describes the design and development of an electrochemical oxygen sensor for use in sodium using a YSZ electrolyte through the previously-mentioned steps. The designed sensors were subjected to a series of hypotheses which advance common understanding of oxygen sensor signal. These results were used in conjunction with past research to form reliable conclusions.

  1. A water-soluble luminescence oxygen sensor.

    PubMed

    Castellano, F N; Lakowicz, J R

    1998-02-01

    We developed a water-soluble luminescent probe for dissolved oxygen. This probe is based on (Ru[dpp(SO3Na)2]3) cl2, which is a sulfonated analogue of the well-known oxygen probe (Ru[dpp]3)cl2. The compound dpp is 4,7-diphenyl-1,10-phenanthroline and dpp(SO3Na)2 is a disulfonated derivative of the same ligand. In aqueous solution in the absence of oxygen (Ru[dpp(SO3Na)2]3)cl2 displays a lifetime of 3.7 microseconds that decreases to 930 ns on equilibrium with air and 227 ns on equilibrium with 100% oxygen. The Stern-Volmer quenching constant is 11,330 M-1. This high oxygen-quenching constant means that the photoluminescence of Ru(dpp[SO3Na]2)3cl2 is 10% quenched at an oxygen concentration of 8.8 x 10(-6) M, or equilibration with 5.4 torr of oxygen. The oxygen probe dissolved in water displays minimal interactions with lipid vesicles composed of dipalmityl-L-alpha-phosphatidyl glycerol but does appear to interact with human serum albumin. The absorption maximum near 480 nm, long lifetime and large Stokes' shift allow this probe to be used with simple instrumentation based on a light-emitting diode light source, allowing low-cost oxygen sensing in aqueous solutions. To the best of our knowledge this is the first practical water-soluble oxygen sensor. PMID:9487796

  2. An oxygen pressure sensor using surface acoustic wave devices

    NASA Technical Reports Server (NTRS)

    Leighty, Bradley D.; Upchurch, Billy T.; Oglesby, Donald M.

    1993-01-01

    Surface acoustic wave (SAW) piezoelectric devices are finding widespread applications in many arenas, particularly in the area of chemical sensing. We have developed an oxygen pressure sensor based on coating a SAW device with an oxygen binding agent which can be tailored to provide variable sensitivity. The coating is prepared by dissolving an oxygen binding agent in a toluene solution of a copolymer which is then sprayed onto the surface of the SAW device. Experimental data shows the feasibility of tailoring sensors to measure the partial pressure of oxygen from 2.6 to 67 KPa (20 to 500 torr). Potential applications of this technology are discussed.

  3. Acute hypoxia modifies cAMP levels induced by inhibitors of phosphodiesterase-4 in rat carotid bodies, carotid arteries and superior cervical ganglia

    PubMed Central

    Nunes, Ana R; Batuca, Joana R; Monteiro, Emília C

    2010-01-01

    Background and purpose: Phosphodiesterase (PDE) inhibitors are useful to treat hypoxia-related diseases and are used in experiments studying the effects of oxygen on 3′-5′-cyclic adenosine monophosphate (cAMP) production. We studied the effects of acute hypoxia on cAMP accumulation induced by PDE inhibitors in oxygen-specific chemosensors, the carotid bodies (CBs) and in non-chemosensitive CB-related structures: carotid arteries (CAs) and superior cervical ganglia (SCG). Experimental approach: Concentration–response curves for the effects of a non-specific PDE inhibitor [isobutylmethylxanthine (IBMX) ], PDE4 selective inhibitors (rolipram, Ro 20-1724) and a PDE2 selective inhibitor (erythro-9-(2-hydroxy-3-nonyl)adenine) on cAMP levels were obtained in normoxic (20% O2/5% CO2) or hypoxic (5% O2/5% CO2) conditions. Key results: Responses to the PDE inhibitors were compatible with the presence of PDE4 in rat CBs, CAs and SCG but in the absence of PDE2 in CAs and CBs. Acute hypoxia enhanced the effects of IBMX and PDE4 inhibitors on cAMP accumulation in CAs and CBs. In SCG, acute hypoxia reduced cAMP accumulation induced by all the four PDE inhibitors tested. Differences between the effects of Ro 20-1724 and rolipram on cAMP were found in CAs and CBs during hypoxia. Conclusions and implications: The effects of PDE4 inhibitors could be potentiated or inhibited by acute hypoxia depending on the PDE isoforms of the tissue. The similarities between the characterization of PDE4 inhibitors at the CBs and CAs, under normoxia and hypoxia, did not support a specific role for cAMP in the oxygen-sensing machinery at the CB and suggested that no direct CB-mediated, hyperventilatory, adverse effects would be expected with administration of PDE4 inhibitors. PMID:20082613

  4. 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.

  5. The story of oxygen.

    PubMed

    Heffner, John E

    2013-01-01

    The history of oxygen from discovery to clinical application for patients with chronic lung disease represents a long and storied journey. Within a relatively short period, early investigators not only discovered oxygen but also recognized its importance to life and its role in respiration. The application of oxygen to chronic lung disease, however, took several centuries. In the modern era, physiologists pursued the chemical nature of oxygen and its physiologic interaction with cellular metabolism and gas transport. It took brazen clinicians, however, to pursue oxygen as a therapeutic resource for patients with chronic lung disease because of the concern in the 20th century of the risks of oxygen toxicity. Application of ambulatory oxygen devices allowed landmark investigations of the long-term effects of continuous oxygen that established its safety and efficacy. Although now well established for hypoxic patients, many questions remain regarding the benefits of oxygen for varying severity and types of chronic lung disease. PMID:23271817

  6. Investigations of new potentiometric gas sensing systems

    SciTech Connect

    Yim, Hyoung-Sik

    1992-01-01

    Research concerning the development of new and/or improved potentiometric gas sensing systems is described. Studies relating to the development of reversible potentiometric oxygen sensors based on polymeric and metallic film electrodes are presented. In addition, the design and analytical utility of a novel differential ion-selective membrane electrode-based potentiometric gas sensing cell with enhanced sensitivity is documented. The performance of a reversible potentiometric oxygen gas sensor based on a polymeric membrane doped with cobalt-complexes is described. For such sensors, the potentiometric oxygen response is attributed to a mixed potential originating from the underlying platinum electrode surface as well as the Co(II)-tetren doped film. This leads to a short term oxygen response of nearly the theoretical slope value of 118 mV/decade, below 10% O[sub 2]. In the presence of the Co(II)-tetren/PVC film, an analytically useful response is observed for approx. 6-8 days. Thin films of metallic copper, electrochemically deposited on platinum and sputtered on a single crystal silicon wafer, are also examined for reversible potentiometric oxygen sensing. The long-term reversibility and potentiometric stability of such copper film-based sensors is enhanced (up to one month) by preventing the formation of cuprous oxide on the surfaces via the application of an external non-polarizing cathodic current through the working electrode, or by specifically using sputtered copper films that have [100] crystal structures as determined by X-ray diffraction. Finally, the development and application of a differential ion-selective membrane electrode-based potentiometric gas sensing cell is described. The prospects of fabricating differential detection arrangements for CO[sub 2], NO[sub 2], and SO[sub 2], NH[sub 3] are also discussed.

  7. [Acute myocarditis].

    PubMed

    Combes, Alain

    2012-06-01

    Myocarditis is defined as inflammation of the myocardium accompanied by myocellular necrosis. Acute myocarditis must be considered in patients who present with recent-onset of cardiac failure or arrhythmia. Fulminant myocarditis is a distinct entity characterized by sudden onset of severe congestive heart failure or cardiogenic shock, usually following a flu-like illness, parvovirus B19, human herpesvirus 6, coxsackievirus and adenovirus being the most frequently viruses responsible for the disease. Treatment of myocarditis remains largely supportive, since immunosuppression has not been proven to be beneficial for acute lymphocytic myocarditis. Trials of antiviral therapies, or immunostimulants such as interferons, suggest a potential therapeutic role but require further investigation. Lastly, early recognition of patients rapidly progressing to refractory cardiac failure and their immediate transfer to a medical-surgical center experienced in mechanical circulatory support is warranted. In this setting, ECMO should be the first-line mechanical assistance. For highly unstable patients, a Mobile Cardiac Assistance Unit, that rapidly travels to primary care hospitals with a portable ECMO system and hooks it up before refractory multiorgan failure takes hold, is the preferred option. PMID:22515999

  8. [Acute myocarditis].

    PubMed

    Combes, Alain

    2013-05-01

    Myocarditis is defined as inflammation of the myocardium accompanied by myocellular necrosis. Acute myocarditis must be considered in patients who present with recent onset of cardiac failure or arrhythmia. Fulminant myocarditis is a distinct entity characterized by sudden onset of severe congestive heart failure or cardiogenic shock, usually following a flu-like illness, parvovirus B19, human herpesvirus 6, coxsackievirus and adenovirus being the most frequently viruses responsible for the disease. Treatment of myocarditis remains largely supportive, since immunosuppression has not been proven to be beneficial for acute lymphocytic myocarditis. Trials of antiviral therapies, or immunostimulants such as interferons, suggest a potential therapeutic role but require further investigation. Lastly, early recognition of patients rapidly progressing to refractory cardiac failure and their immediate transfer to a medical-surgical center experienced in mechanical circulatory support is warranted. In this setting, ECMO should be the first-line mechanical assistance. For highly unstable patients, a Mobile Cardiac Assistance Unit, that rapidly travels to primary care hospitals with a portable ECMO system and hooks it up before refractory multiorgan failure takes hold, is the preferred option. PMID:23789482

  9. An oxygen enrichment device for lowlanders ascending to high altitude

    PubMed Central

    2013-01-01

    Background When ascending to the high altitude, people living in low altitude areas will suffer from acute mountain sickness. The aim of this study is to test the hypothesis that whether an oxygen concentration membrane can be made and used to construct a new portable oxygen enrichment device for individuals in acute exposure to the high altitude. Methods The membrane was fabricated using vinylsiloxane rubber, polyphenylene oxide hydrogen silicone polymers, chloroplatinic acid and isopropyl alcohol. The membrane was assembled in a frame and the performance was tested in terms of concentration of oxygen, flow rate of oxygen enriched air, pressure ratio across the membrane and ambient temperature. Furthermore, the oxygen concentration device was constructed using the membrane, a DC fan, vacuum pump and gas buffer. A nonrandomized preliminary field test was conducted, in which eight healthy male subjects were flown to Tibet (Lhasa, 3,700 m). First, subjects wore the oxygen enrichment device and performed an incremental exercise on cycle ergometer. The test included heart rate (HR), saturation of peripheral oxygen (SpO2) and physical work capacity (PWC). Then, after a rest period of 4 hours, the experimental protocol was repeated without oxygen enrichment device. Results The testing showed that the membrane could increase the oxygen concentration by up to 30%. Simulation test indicated that although the performance of the oxygen enrichment device decreased with altitudes, the oxygen concentration could still maintain 28% with flow rate of enriched air 110 cm3/s at 5000 m. The field test showed that higher SpO2, lower HR, and better PWC (measured by the PWC-170) were observed from all the subjects using oxygen enrichment device compared with non-using (P < 0.01). Conclusions We concluded that the new portable oxygen enrichment device would be effective in improving exercise performance when ascending to the high altitude. PMID:24103365

  10. Anemia and Oxygen Delivery.

    PubMed

    Bliss, Stuart

    2015-09-01

    Clinical assessment of tissue oxygenation is challenging. Anemia reflects a decreased oxygen carrying capacity of the blood and its significance in the perioperative setting relates largely to the associated risk of insufficient oxygen delivery and cellular hypoxia. Until meaningful clinical measures of tissue oxygenation are available in veterinary practice, clinicians must rely on evaluation of a patient's hemodynamic and ventilatory performance, along with biochemical and hemogasometric measurements. Blood transfusion is used commonly for treatment of perioperative anemia, and may improve tissue oxygenation by normalizing the rheologic properties of blood and enhancing perfusion, independent of increases in oxygen carrying capacity. PMID:26033442

  11. Atomic transport of oxygen

    SciTech Connect

    Routbort, J.L.; Tomlins, G.W.

    1994-06-15

    Atomic transport of oxygen in nonstoichiometric oxides is an extremely important topic which overlaps science and technology. In many cases the diffusion of oxygen controls sintering, grain growth, and creep. High oxygen diffusivity is critical for efficient operation of many fuel cells. Additionally, oxygen diffusivities are an essential ingredient in any point defect model. Secondary Ion Mass Spectrometry (SIMS) is the most accurate modern technique to measure oxygen tracer diffusion. This paper briefly reviews the principles and applications of SIMS for the measurement of oxygen transport. Case studies are taken from recent work on ZnO and some high-temperature superconductors.

  12. 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.

  13. 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.

  14. Acute cerebellar ataxia

    MedlinePlus

    Cerebellar ataxia; Ataxia - acute cerebellar; Cerebellitis; Post-varicella acute cerebellar ataxia; PVACA ... Acute cerebellar ataxia in children, especially younger than age 3, may occur several weeks after an illness caused by a virus. ...

  15. Ear infection - acute

    MedlinePlus

    Otitis media - acute; Infection - inner ear; Middle ear infection - acute ... Casselbrandt ML, Mandel EM. Acute otitis media and otitis media with effusion. In: Flint PW, Haughey BH, Lund V, et al, eds. Cummings Otolaryngology: Head & Neck Surgery . 6th ed. ...

  16. Enzymatic Glucose Sensor Compensation for Variations in Ambient Oxygen Concentration

    PubMed Central

    Collier, Bradley B.; McShane, Michael J.

    2014-01-01

    Due to the increasing prevalence of diabetes, research toward painless glucose sensing continues. Oxygen sensitive phosphors with glucose oxidase (GOx) can be used to determine glucose levels indirectly by monitoring oxygen consumption. This is an attractive combination because of its speed and specificity. Packaging these molecules together in “smart materials” for implantation will enable non-invasive glucose monitoring. As glucose levels increase, oxygen levels decrease; consequently, the luminescence intensity and lifetime of the phosphor increase. Although the response of the sensor is dependent on glucose concentration, the ambient oxygen concentration also plays a key role. This could lead to inaccurate glucose readings and increase the risk of hyper- or hypoglycemia. To mitigate this risk, the dependence of hydrogel glucose sensor response on oxygen levels was investigated and compensation methods explored. Sensors were calibrated at different oxygen concentrations using a single generic logistic equation, such that trends in oxygen-dependence were determined as varying parameters in the equation. Each parameter was found to be a function of oxygen concentration, such that the correct glucose calibration equation can be calculated if the oxygen level is known. Accuracy of compensation will be determined by developing an overall calibration, using both glucose and oxygen sensors in parallel, correcting for oxygen fluctuations in real time by intentionally varying oxygen, and calculating the error in actual and predicted glucose levels. While this method was developed for compensation of enzymatic glucose sensors, in principle it can also be implemented with other kinds of sensors utilizing oxidases. PMID:26257458

  17. Drug Therapy for Acute Heart Failure.

    PubMed

    Di Somma, Salvatore; Magrini, Laura

    2015-08-01

    Acute heart failure is globally one of most frequent reasons for hospitalization and still represents a challenge for the choice of the best treatment to improve patient outcome. According to current international guidelines, as soon as patients with acute heart failure arrive at the emergency department, the common therapeutic approach aims to improve their signs and symptoms, correct volume overload, and ameliorate cardiac hemodynamics by increasing vital organ perfusion. Recommended treatment for the early management of acute heart failure is characterized by the use of intravenous diuretics, oxygen, and vasodilators. Although these measures ameliorate the patient's symptoms, they do not favorably impact on short- and long-term mortality. Consequently, there is a pressing need for novel agents in acute heart failure treatment with the result that research in this field is increasing worldwide. PMID:26088867

  18. [Acute pancreatitis with hypertriglyceridemia--an underestimated disease?].

    PubMed

    Wild, Wolfgang; Tajjiou, Morad; Ferschke, Melanie; Bormann, Fabian; Dörr, Pius; Schwarzbach, Matthias

    2016-01-01

    Hypertriglyceridemia is a rare, but since a long time well known etiology for acute pancreatitis. It could occure alone or coactive with other triggers like alcohlic excess. Nevertheless it found no approach to the current classifications and parameters of prognosis of the acute pancreatitis. We refer about two patients with hypertriglyceridemia and acute pancreatitis, whose initial disease was limited on the tail of the pancreas with just a circumscripted or--in the other case--no necrosis. However, in both cases and although a consequent treatment started immediately, a serious process developed including a life-threatening acute respiratory distress syndrome in one case, which necessitated an extracorporal membrane oxygenation. PMID:26710203

  19. Peroxiredoxin-5 targeted to the mitochondrial intermembrane space attenuates hypoxia-induced reactive oxygen species signalling.

    PubMed

    Sabharwal, Simran S; Waypa, Gregory B; Marks, Jeremy D; Schumacker, Paul T

    2013-12-15

    The ability to adapt to acute and chronic hypoxia is critical for cellular survival. Two established functional responses to hypoxia include the regulation of gene transcription by HIF (hypoxia-inducible factor), and the constriction of pulmonary arteries in response to alveolar hypoxia. The mechanism of O2 sensing in these responses is not established, but some studies implicate hypoxia-induced mitochondrial ROS (reactive oxygen species) signalling. To further test this hypothesis, we expressed PRDX5 (peroxiredoxin-5), a H2O2 scavenger, in the IMS (mitochondrial intermembrane space), reasoning that the scavenging of ROS in that compartment should abrogate cellular responses triggered by the release of mitochondrial oxidants to the cytosol. Using adenoviral expression of IMS-PRDX5 (IMS-targeted PRDX5) in PASMCs (pulmonary artery smooth muscle cells) we show that IMS-PRDX5 inhibits hypoxia-induced oxidant signalling in the IMS and cytosol. It also inhibits HIF-1α stabilization and HIF activity in a dose-dependent manner without disrupting cellular oxygen consumption. IMS-PRDX5 expression also attenuates the increase in cytosolic [Ca(2+)] in PASMCs during hypoxia. These results extend previous work by demonstrating the importance of IMS-derived ROS signalling in both the HIF and lung vascular responses to hypoxia. PMID:24044889

  20. 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.

  1. A Distributed Chemosensory Circuit for Oxygen Preference in C. elegans

    PubMed Central

    Chang, Andy J; Chronis, Nikolas; Karow, David S; Marletta, Michael A; Bargmann, Cornelia I

    2006-01-01

    The nematode Caenorhabditis elegans has complex, naturally variable behavioral responses to environmental oxygen, food, and other animals. C. elegans detects oxygen through soluble guanylate cyclase homologs (sGCs) and responds to it differently depending on the activity of the neuropeptide receptor NPR-1: npr-1(lf) and naturally isolated npr-1(215F) animals avoid high oxygen and aggregate in the presence of food; npr-1(215V) animals do not. We show here that hyperoxia avoidance integrates food with npr-1 activity through neuromodulation of a distributed oxygen-sensing network. Hyperoxia avoidance is stimulated by sGC-expressing oxygen-sensing neurons, nociceptive neurons, and ADF sensory neurons. In npr-1(215V) animals, the switch from weak aerotaxis on food to strong aerotaxis in its absence requires close regulation of the neurotransmitter serotonin in the ADF neurons; high levels of ADF serotonin promote hyperoxia avoidance. In npr-1(lf) animals, food regulation is masked by increased activity of the oxygen-sensing neurons. Hyperoxia avoidance is also regulated by the neuronal TGF-β homolog DAF-7, a secreted mediator of crowding and stress responses. DAF-7 inhibits serotonin synthesis in ADF, suggesting that ADF serotonin is a convergence point for regulation of hyperoxia avoidance. Coalitions of neurons that promote and repress hyperoxia avoidance generate a subtle and flexible response to environmental oxygen. PMID:16903785

  2. 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 ...

  3. Home Oxygen Therapy

    MedlinePlus

    ... important advantage of liquid oxygen is you can transfer some of the liquid oxygen into a smaller, ... from gas stoves, candles, lighted fireplaces, or other heat sources. Don't use any flammable products like ...

  4. Miniature oxygen resuscitator

    NASA Technical Reports Server (NTRS)

    Johnson, G.; Teegen, J. T.; Waddell, H.

    1969-01-01

    Miniature, portable resuscitation system is used during evacuation of patients to medical facilities. A carrying case contains a modified resuscitator head, cylinder of oxygen, two-stage oxygen regulator, low pressure tube, and a mask for mouth and nose.

  5. Acute pain.

    PubMed

    Good, M

    1999-01-01

    The review of acute pain describes the problem of unresolved pain and its effects on the neural, autonomic, and immune systems. Conceptualizations and mechanisms of pain are reviewed as well as theories of pain management. Descriptive studies of patient and nurse factors that inhibit effective pain management are discussed, followed by studies of pharmacological and nonpharmacological interventions. Critical analysis reveals that most studies were atheoretical, and therefore, this proliferation of information lacked conceptual coherence and organization. Furthermore, the nature and extent of barriers to pain management were described, but few intervention studies have been devised, as yet, to modify the knowledge, beliefs, and attitudes of nurses and patients that are barriers to pain management. Although some of the complementary therapies have sufficient research support to be used in clinical pain management, the physiological mechanisms and outcomes need to be studied. It is critical at this time to design studies of interventions to improve assessment, decision making, attentive care, and patient teaching. PMID:10418655

  6. Pharmacological management of acute bronchiolitis

    PubMed Central

    Wright, Melvin; Mullett, Charles J; Piedimonte, Giovanni

    2008-01-01

    This article reviews the current knowledge base related to the pharmacological treatments for acute bronchiolitis. Bronchiolitis is a common lower respiratory illness affecting infants worldwide. The mainstays of therapy include airway support, supplemental oxygen, and support of fluids and nutrition. Frequently tried pharmacological interventions, such as ribavirin, nebulized bronchodilators, and systemic corticosteroids, have not been proven to benefit patients with bronchiolitis. Antibiotics do not improve the clinical course of patients with bronchiolitis, and should be used only in those patients with proven concurrent bacterial infection. Exogenous surfactant and heliox therapy also cannot be recommended for routine use, but surfactant replacement holds promise and should be further studied. PMID:19209271

  7. 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.

  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. [Domiciliary oxygen therapy].

    PubMed

    Abdel Kafi, S

    2010-09-01

    In Belgium, oxygen therapy is becoming more and more accessible. When oxygen is needed for short periods or for special indications as palliative care, an agreement between mutual insurance companies and pharmacists allows the practitioner the home installation of gazeous oxygen cylinder or of oxygen concentrator. When long term oxygen therapy (LTOT) is indicated for patients with respiratory insufficiency, the pneumologist must first ask the INAMI the authorization to install one of the following modalities: oxygen concentrator with or without demand oxygen delivery cylinder and liquid oxygen. The goal of LTOT is to increase survival and quality of life. The principal and well accepted indication for LTOT is severe hypoxemia. The beneficial effects of oxygen therapy limited at night or on exertion are controversial. In order to increase patient's autonomy, oxygen can be prescribed for ambulation, respecting prescription's rules. At each step of oxygen therapy implementing (indication, choice of the device and follow-up) the patient under oxygen may benefit from a joint approach between the general practitioner and the chest specialist. PMID:21089403

  10. Medical Oxygen Safety

    MedlinePlus

    ... to the air a patient uses to breathe. Fire needs oxygen to burn. If a fire should start in an oxygen-enriched area, the ... Homes where medical oxygen is used need specific fire safety rules to keep people safe from fire ...

  11. Mobile sensing systems.

    PubMed

    Macias, Elsa; Suarez, Alvaro; Lloret, Jaime

    2013-01-01

    Rich-sensor smart phones have made possible the recent birth of the mobile sensing research area as part of ubiquitous sensing which integrates other areas such as wireless sensor networks and web sensing. There are several types of mobile sensing: individual, participatory, opportunistic, crowd, social, etc. The object of sensing can be people-centered or environment-centered. The sensing domain can be home, urban, vehicular… Currently there are barriers that limit the social acceptance of mobile sensing systems. Examples of social barriers are privacy concerns, restrictive laws in some countries and the absence of economic incentives that might encourage people to participate in a sensing campaign. Several technical barriers are phone energy savings and the variety of sensors and software for their management. Some existing surveys partially tackle the topic of mobile sensing systems. Published papers theoretically or partially solve the above barriers. We complete the above surveys with new works, review the barriers of mobile sensing systems and propose some ideas for efficiently implementing sensing, fusion, learning, security, privacy and energy saving for any type of mobile sensing system, and propose several realistic research challenges. The main objective is to reduce the learning curve in mobile sensing systems where the complexity is very high. PMID:24351637

  12. Mobile Sensing Systems

    PubMed Central

    Macias, Elsa; Suarez, Alvaro; Lloret, Jaime

    2013-01-01

    Rich-sensor smart phones have made possible the recent birth of the mobile sensing research area as part of ubiquitous sensing which integrates other areas such as wireless sensor networks and web sensing. There are several types of mobile sensing: individual, participatory, opportunistic, crowd, social, etc. The object of sensing can be people-centered or environment-centered. The sensing domain can be home, urban, vehicular… Currently there are barriers that limit the social acceptance of mobile sensing systems. Examples of social barriers are privacy concerns, restrictive laws in some countries and the absence of economic incentives that might encourage people to participate in a sensing campaign. Several technical barriers are phone energy savings and the variety of sensors and software for their management. Some existing surveys partially tackle the topic of mobile sensing systems. Published papers theoretically or partially solve the above barriers. We complete the above surveys with new works, review the barriers of mobile sensing systems and propose some ideas for efficiently implementing sensing, fusion, learning, security, privacy and energy saving for any type of mobile sensing system, and propose several realistic research challenges. The main objective is to reduce the learning curve in mobile sensing systems where the complexity is very high. PMID:24351637

  13. Brain Oxygenation Monitoring.

    PubMed

    Kirkman, Matthew A; Smith, Martin

    2016-09-01

    A mismatch between cerebral oxygen supply and demand can lead to cerebral hypoxia/ischemia and deleterious outcomes. Cerebral oxygenation monitoring is an important aspect of multimodality neuromonitoring. It is increasingly deployed whenever intracranial pressure monitoring is indicated. Although there is a large body of evidence demonstrating an association between cerebral hypoxia/ischemia and poor outcomes, it remains to be determined whether restoring cerebral oxygenation leads to improved outcomes. Randomized prospective studies are required to address uncertainties about cerebral oxygenation monitoring and management. This article describes the different methods of monitoring cerebral oxygenation, their indications, evidence base, limitations, and future perspectives. PMID:27521197

  14. Oxygen configurations in silica

    SciTech Connect

    Chelikowsky, James R.; Chadi, D. J.; Binggeli, N.

    2000-07-15

    We propose a transition state for oxygen in silica. This state is produced by the insertion of an oxygen molecule into the Si-O-Si bond, i.e., it consists of producing a Si-O-O-O-Si bond. This state allows molecular oxygen diffusion in silica without breaking the molecular O{sub 2} bond and it is energetically more stable than a peroxy configuration. This configuration may allow for exchange of molecular oxygen with the oxygen in the silica framework. (c) 2000 The American Physical Society.

  15. [Etiology and pathogenesis of acute respiratory failure].

    PubMed

    Ziliene, Violeta; Kondrotas, Anatolijus Juozas; Kevelaitis, Egidijus

    2004-01-01

    The aim of this study was to determine factors influencing acute respiratory failure and pathogenesis according to literature and clinical findings in critically ill patients. The term "respiratory failure" implies the inability to maintain either the normal delivery of oxygen to tissues and release or the normal removal of carbon dioxide from the tissues. There are many patients suffering from acute respiratory failure caused by nosocomial pneumonia, septic syndrome, aspiration, interstitial or alveolar lung edema, thromboembolism of a. pulmonalis, polytrauma and lung contusion, acute respiratory distress syndrome, long-term mechanical ventilation of the lungs, acute lung injury, status asthmaticus, rather massive transfusions of blood products, and lipid embolism in the intensive care unit. There are actually three processes involved: the transfer of oxygen across the alveolus, the transport to the tissues (by cardiac output), and the removal of carbon dioxide from blood into the alveolus with subsequent exhalation into the environment. Failure of any step in this process can lead to respiratory failure. Long-term hypoxia causes ischemic changes and dysfunction of brain, heart, kidney, lungs and can worsen the course of disease or cause higher mortality. It is important to determine the pathogenetic mechanisms of acute respiratory failure, estimate the main parameters and their interrelations and prescribe proper treatment. PMID:15064552

  16. [Acute respiratory distress syndrome].

    PubMed

    Estenssoro, Elisa; Dubin, Arnaldo

    2016-01-01

    Acute respiratory distress syndrome (ARDS) is an acute respiratory failure produced by an inflammatory edema secondary to increased lung capillary permeability. This causes alveolar flooding and subsequently deep hypoxemia, with intrapulmonary shunt as its most important underlying mechanism. Characteristically, this alteration is unresponsive to high FIO2 and only reverses with end-expiratory positive pressure (PEEP). Pulmonary infiltrates on CXR and CT are the hallmark, together with decreased lung compliance. ARDS always occurs within a week of exposition to a precipitating factor; most frequently pneumonia, shock, aspiration of gastric contents, sepsis, and trauma. In CT scan, the disease is frequently inhomogeneous, with gravitational infiltrates coexisting with normal-density areas and also with hyperaerated parenchyma. Mortality is high (30-60%) especially in ARDS associated with septic shock and neurocritical diseases. The cornerstone of therapy lies in the treatment of the underlying cause and in the use mechanical ventilation which, if inappropriately administered, can lead to ventilator-induced lung injury. Tidal volume = 6 ml/kg of ideal body weight to maintain an end-inspiratory (plateau) pressure = 30 cm H2O ("protective ventilation") is the only variable consistently associated with decreased mortality. Moderate-to-high PEEP levels are frequently required to treat hypoxemia, yet no specific level or titration strategy has improved outcomes. Recently, the use of early prone positioning in patients with PaO2/FIO2 = 150 was associated with increased survival. In severely hypoxemic patients, it may be necessary to use adjuvants of mechanical ventilation as recruitment maneuvers, pressure-controlled modes, neuromuscular blocking agents, and extracorporeal-membrane oxygenation. Fluid restriction appears beneficial. PMID:27576283

  17. Tropospheric Passive Remote Sensing

    NASA Technical Reports Server (NTRS)

    Keafer, L. S., Jr. (Editor)

    1982-01-01

    The long term role of airborne/spaceborne passive remote sensing systems for tropospheric air quality research and the identification of technology advances required to improve the performance of passive remote sensing systems were discussed.

  18. SUPERFUND REMOTE SENSING SUPPORT

    EPA Science Inventory

    This task provides remote sensing technical support to the Superfund program. Support includes the collection, processing, and analysis of remote sensing data to characterize hazardous waste disposal sites and their history. Image analysis reports, aerial photographs, and assoc...

  19. Oxygen pressure measurement using singlet oxygen emission

    SciTech Connect

    Khalil, Gamal E.; Chang, Alvin; Gouterman, Martin; Callis, James B.; Dalton, Larry R.; Turro, Nicholas J.; Jockusch, Steffen

    2005-05-15

    Pressure sensitive paint (PSP) provides a visualization of two-dimensional pressure distributions on airfoil and model automobile surfaces. One type of PSP utilizes platinum tetra(pentafluorophenyl)porphine (PtTFPP) dissolved in a fluoro-polymer film. Since the intense 650 nm triplet emission of PtTFPP is quenched by ground state oxygen, it is possible to measure two-dimensional oxygen concentration from the 650 nm emission intensity using a Stern-Volmer-type relationship. This article reports an alternative luminescence method to measure oxygen concentration based on the porphyrin-sensitized 1270 nm singlet oxygen emission, which can be imaged with an InGaAs near infrared camera. This direct measurement of oxygen emission complements and further validates the oxygen measurement based on PtTFPP phosphorescence quenching. Initial success at obtaining a negative correlation between the 650 nm PtTFPP emission and the 1270 nm O{sub 2} emission in solution led us to additional two-dimensional film studies using surfaces coated with PtTFPP, MgTFPP, and H{sub 2}TFPP in polymers in a pressure and temperature controlled chamber.

  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. PMID:16566709

  1. Math Sense: Placement Test.

    ERIC Educational Resources Information Center

    2003

    Math Sense consists of five books that develop from basic to more advanced math skills. This document contains a placement test used with Math Sense to help students and their teachers decide into which Math Sense book to begin working. The placement test is divided into six parts, each consisting of 10 to 22 problems, and is based on exit skill…

  2. Acute kidney injury due to decompression illness.

    PubMed

    Viecelli, Andrea; Jamboti, Jagadish; Waring, Andrew; Banham, Neil; Ferrari, Paolo

    2014-08-01

    Decompression illness is a rare but serious complication of diving caused by intravascular or extravascular gas bubble formation. We report the first case of acute kidney injury in a 27-year-old diver following three rapid ascents. He presented with transient neurological symptoms and abdominal pain followed by rapidly progressive acute kidney injury (creatinine peak 1210 µmol/L) due to arterial air emboli. He received supportive care and 100% oxygen followed by hyperbaric therapy and recovered fully. Arterial air emboli caused by rapid decompression can affect multiple organs including the kidneys. Early transfer to a hyperbaric unit is important as complications may present delayed. PMID:25852912

  3. Acute kidney injury due to decompression illness

    PubMed Central

    Viecelli, Andrea; Jamboti, Jagadish; Waring, Andrew; Banham, Neil; Ferrari, Paolo

    2014-01-01

    Decompression illness is a rare but serious complication of diving caused by intravascular or extravascular gas bubble formation. We report the first case of acute kidney injury in a 27-year-old diver following three rapid ascents. He presented with transient neurological symptoms and abdominal pain followed by rapidly progressive acute kidney injury (creatinine peak 1210 µmol/L) due to arterial air emboli. He received supportive care and 100% oxygen followed by hyperbaric therapy and recovered fully. Arterial air emboli caused by rapid decompression can affect multiple organs including the kidneys. Early transfer to a hyperbaric unit is important as complications may present delayed. PMID:25852912

  4. Optical Oxygen Micro- and Nanosensors for Plant Applications

    PubMed Central

    Ast, Cindy; Schmälzlin, Elmar; Löhmannsröben, Hans-Gerd; van Dongen, Joost T.

    2012-01-01

    Pioneered by Clark's microelectrode more than half a century ago, there has been substantial interest in developing new, miniaturized optical methods to detect molecular oxygen inside cells. While extensively used for animal tissue measurements, applications of intracellular optical oxygen biosensors are still scarce in plant science. A critical aspect is the strong autofluorescence of the green plant tissue that interferes with optical signals of commonly used oxygen probes. A recently developed dual-frequency phase modulation technique can overcome this limitation, offering new perspectives for plant research. This review gives an overview on the latest optical sensing techniques and methods based on phosphorescence quenching in diverse tissues and discusses the potential pitfalls for applications in plants. The most promising oxygen sensitive probes are reviewed plus different oxygen sensing structures ranging from micro-optodes to soluble nanoparticles. Moreover, the applicability of using heterologously expressed oxygen binding proteins and fluorescent proteins to determine changes in the cellular oxygen concentration are discussed as potential non-invasive cellular oxygen reporters. PMID:22969334

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. Hyperbaric Oxygen Therapy Registry

    ClinicalTrials.gov

    2016-05-18

    Air or Gas Embolism; Carbon Monoxide Poisoning; Clostridial Myositis and Myonecrosis (Gas Gangrene); Crush Injury, Compartment Syndrome & Other Acute Traumatic Ischemias; Decompression Sickness; Peripheral Arterial Insufficiency and Central Retinal Artery Occlusion; Severe Anemia; Intracranial Abscess; Necrotizing Soft Tissue Infections; Osteomyelitis (Refractory); Delayed Radiation Injury (Soft Tissue and Bony Necrosis); Compromised Grafts and Flaps; Acute Thermal Burn Injury; Idiopathic Sudden Sensorineural Hearing Loss

  11. Oxygen is an essential medicine: a call for international action

    PubMed Central

    Duke, T.; Graham, S. M.; Cherian, M. N.; Ginsburg, A. S.; English, M.; Howie, S.; Peel, D.; Enarson, P. M.; Wilson, I. H.; Were, W.

    2010-01-01

    SUMMARY Hypoxaemia is commonly associated with mortality in developing countries, yet feasible and cost-effective ways to address hypoxaemia receive little or no attention in current global health strategies. Oxygen treatment has been used in medicine for almost 100 years, but in developing countries most seriously ill newborns, children and adults do not have access to oxygen or the simple test that can detect hypoxaemia. Improving access to oxygen and pulse oximetry has demonstrated a reduction in mortality from childhood pneumonia by up to 35% in high-burden child pneumonia settings. The cost-effectiveness of an oxygen systems strategy compares favourably with other higher profile child survival interventions, such as new vaccines. In addition to its use in treating acute respiratory illness, oxygen treatment is required for the optimal management of many other conditions in adults and children, and is essential for safe surgery, anaesthesia and obstetric care. Oxygen concentrators provide the most consistent and least expensive source of oxygen in health facilities where power supplies are reliable. Oxygen concentrators are sustainable in developing country settings if a systematic approach involving nurses, doctors, technicians and administrators is adopted. Improving oxygen systems is an entry point for improving the quality of care. For these broad reasons, and for its vital importance in reducing deaths due to lung disease in 2010: Year of the Lung, oxygen deserves a higher priority on the global health agenda. PMID:20937173

  12. REMOTE SENSING TECHNOLOGIES APPLICATIONS RESEARCH

    EPA Science Inventory

    Remote sensing technologies applications research supports the ORD Landscape Sciences Program (LSP) in two separate areas: operational remote sensing, and remote sensing research and development. Operational remote sensing is provided to the LSP through the use of current and t...

  13. Extracorporeal membrane oxygenation for hydrocarbon aspiration.

    PubMed

    Scalzo, A J; Weber, T R; Jaeger, R W; Connors, R H; Thompson, M W

    1990-08-01

    Extracorporeal membrane oxygenation is a pulmonary bypass procedure that has been employed in adults to provide temporary treatment for reversible acute pulmonary and cardiac insufficiency. The technology of membrane oxygenation has been used since 1977 in neonates with predictably fatal pulmonary failure due to respiratory distress syndrome, persistent fetal circulation or persistent pulmonary hypertension of the newborn, meconium aspiration syndrome, and congenital diaphragmatic hernia. The use of extracorporeal membrane oxygenation in older children with other pulmonary disorders has been limited. We report two cases of hydrocarbon aspiration involving petroleum-based products, both successfully treated with extracorporeal membrane oxygenation. A 15-month-old male infant who aspirated baby oil (light mineral oil) is particularly unusual owing to the generally expected low risk of aspiration with a hydrocarbon of such viscosity (greater than 60 Saybolt Universal Seconds). The second patient is a 16-month-old male infant who aspirated furniture polish (mineral seal oil). In both children severe intractable hypoxemia developed despite intensive ventilatory support, and they became candidates for alternative therapy. Extracorporeal membrane oxygenation provides a potentially life-saving option when a patient fails to respond to conventional therapy for hydrocarbon aspiration. PMID:2378332

  14. Plant gravity sensing

    NASA Technical Reports Server (NTRS)

    Sack, F. D.

    1991-01-01

    This review of plant gravity sensing examines sensing in organ gravitropism, sensing in single-cell gravitropism, and nongravitropic sensing. Topics related to sensing in organ gravitropism are (1) identification of the gravitropic susceptors, including intracellular asymmetry in equilibrium position and after reorientation, susceptor signal-to-noise ratio, signal integration over threshold stimulation periods, intracellular asymmetry and gravitropic competence, and starch deficiency and gravitropic competence; (2) possible root statocytes and receptors, including identification of presumptive statocytes, cytology, and possible receptors and models of sensing; and (3) negatively gravitropic organs, including identification and distribution of presumptive statocytes and cytology and possible receptors. Topics related to nongravitropic sensing include gravitaxis, reaction wood, gravimorphogenesis, other gravity-influenced organ movements, and cytoplasmic streaming.

  15. Acute coronary syndrome

    PubMed Central

    Jawaid, Saad; Chaudary, Adeel

    2014-01-01

    The paramedics brought a 60-year-old man to the emergency department after a sudden onset of shortness of breath with a subsequent drop in the Glasgow Coma Scale (GCS). On arrival the patient looked peri-arrest. His O2 saturations were 84% on 15 L of oxygen. He had gasping breathing with a completely silent chest and the GCS was 6/15 (E=1, V=1, M=4). The blood gas revealed type-2 respiratory failure. The chest X-ray was unremarkable and ECG was not indicative for cardiac catheterisation lab activation. Bedside shock scan was done which showed global hypokinesia of the left ventricle. In spite of unconvincing ECG and chest X-ray, an acute cardiac event was diagnosed in view of an abnormal bedside echo. The patient was transferred to the cardiac catheterisation lab for urgent percutaneous coronary intervention which revealed critical stenosis of the left main stem coronary artery, which was successfully stented. The patient had a good recovery from the life-threatening event. PMID:24913081

  16. Integrated turbomachine oxygen plant

    DOEpatents

    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.

  17. 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.

  18. 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.

  19. 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.

  20. Oxygen scavenging with enzymes

    SciTech Connect

    Hitzman, D.O.

    1983-11-08

    An effective method of reducing the amount of oxygen present in an aqueous fluid is described, which protects materials otherwise susceptible to oxidative degradation in the presence of free (dissolved) oxygen. The method comprises reacting the oxygen with an alcohol selected from the group consisting of methanol, ethanol, propanol, and butanol, in the further presence of alcohol oxidase. An oxygen containing aqueous fluid is a fluid comprising water and free oxygen. The fluid containing free oxygen can be, for example, oil field fluids, recycle water, foodstuffs, etc. The method is applicable to oil field aqueous fluid systems in order to protect oil field equipment to avoid molecular degradation of polymeric viscosifiers used in floods, etc., and to treat foodstuffs. 17 claims.

  1. 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.

  2. Rockets using Liquid Oxygen

    NASA Technical Reports Server (NTRS)

    Busemann, Adolf

    1947-01-01

    It is my task to discuss rocket propulsion using liquid oxygen and my treatment must be highly condensed for the ideas and experiments pertaining to this classic type of rocket are so numerous that one could occupy a whole morning with a detailed presentation. First, with regard to oxygen itself as compared with competing oxygen carriers, it is known that the liquid state of oxygen, in spite of the low boiling point, is more advantageous than the gaseous form of oxygen in pressure tanks, therefore only liquid oxygen need be compared with the oxygen carriers. The advantages of liquid oxygen are absolute purity and unlimited availability at relatively small cost in energy. The disadvantages are those arising from the impossibility of absolute isolation from heat; consequently, allowance must always be made for a certain degree of vaporization and only vented vessels can be used for storage and transportation. This necessity alone eliminates many fields of application, for example, at the front lines. In addition, liquid oxygen has a lower specific weight than other oxygen carriers, therefore many accessories become relatively larger and heavier in the case of an oxygen rocket, for example, the supply tanks and the pumps. The advantages thus become effective only in those cases where definitely scheduled operation and a large ground organization are possible and when the flight requires a great concentration of energy relative to weight. With the aim of brevity, a diagram of an oxygen rocket will be presented and the problem of various component parts that receive particularly thorough investigation in this classic case but which are also often applicable to other rocket types will be referred to.

  3. Acute pulmonary oedema in pregnant women.

    PubMed

    Dennis, A T; Solnordal, C B

    2012-06-01

    Acute pulmonary oedema in pregnant women is an uncommon but life-threatening event. The aims of this review are to address why pulmonary oedema occurs in pregnant women and to discuss immediate management. We performed a systematic literature search of electronic databases including MEDLINE, EMBASE and the Cochrane Library, using the key words obstetrics, pregnancy, acute pulmonary oedema, pregnancy complications, maternal, cardiac function and haemodynamics. We present a simple clinical classification of acute pulmonary oedema in pregnancy into pulmonary oedema occurring in normotensive or hypotensive women (i.e. without hypertension), and acute pulmonary oedema occurring in hypertensive women, which allows focused management. Pre-eclampsia remains an important cause of hypertensive acute pulmonary oedema in pregnancy and preventive strategies include close clinical monitoring and restricted fluid administration. Immediate management of acute pulmonary oedema includes oxygenation, ventilation and circulation control with venodilators. Pregnancy-specific issues include consideration of the physiological changes of pregnancy, the risk of aspiration and difficult airway, reduced respiratory and metabolic reserve, avoidance of aortocaval compression and delivery of the fetus. PMID:22420683

  4. 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.

  5. 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.

  6. Quantitating intracellular oxygen tension in vivo by phosphorescence lifetime measurement

    PubMed Central

    Hirakawa, Yosuke; Yoshihara, Toshitada; Kamiya, Mako; Mimura, Imari; Fujikura, Daichi; Masuda, Tsuyoshi; Kikuchi, Ryohei; Takahashi, Ippei; Urano, Yasuteru; Tobita, Seiji; Nangaku, Masaomi

    2015-01-01

    Hypoxia appears to have an important role in pathological conditions in many organs such as kidney; however, a method to quantify intracellular oxygen tension in vivo has not been well established. In this study, we established an optical method to quantify oxygen tension in mice kidneys using a cationic lipophilic phosphorescence probe, BTPDM1, which has an intracellular oxygen concentration-sensitive phosphorescence lifetime. Since this probe is distributed inside the tubular cells of the mice kidney, we succeeded in detecting acute renal hypoxic conditions and chronic kidney disease. This technique enabled us to estimate intracellular partial pressures of oxygen in vivo by extrapolating the calibration curve generated from cultured tubular cells. Since intracellular oxygen tension is directly related to cellular hypoxic reactions, such as the activation of hypoxia-inducible factors, our method will shed new light on hypoxia research in vivo. PMID:26644023

  7. Oxygen indicators and intelligent inks for packaging food.

    PubMed

    Mills, Andrew

    2005-12-01

    The detection of oxygen using optical sensors is of increasing interest, especially in modified atmosphere food packaging (MAP), in which the package, usually containing food, is flushed with a gas, such as carbon dioxide or nitrogen. This tutorial review examines the ideal properties of an oxygen optical sensor for MAP and compares them with those developed to date, including the most recent advances. The basic technologies underpinning the different indicator types are described, examples given and their potential for application in MAP assessed. This tutorial review should be of interest to the MAP industry and researchers in optical sensors and oxygen sensing. PMID:16284666

  8. Optical Oxygen Sensors for Applications in Microfluidic Cell Culture

    PubMed Central

    Grist, Samantha M.; Chrostowski, Lukas; Cheung, Karen C.

    2010-01-01

    The presence and concentration of oxygen in biological systems has a large impact on the behavior and viability of many types of cells, including the differentiation of stem cells or the growth of tumor cells. As a result, the integration of oxygen sensors within cell culture environments presents a powerful tool for quantifying the effects of oxygen concentrations on cell behavior, cell viability, and drug effectiveness. Because microfluidic cell culture environments are a promising alternative to traditional cell culture platforms, there is recent interest in integrating oxygen-sensing mechanisms with microfluidics for cell culture applications. Optical, luminescence-based oxygen sensors, in particular, show great promise in their ability to be integrated with microfluidics and cell culture systems. These sensors can be highly sensitive and do not consume oxygen or generate toxic byproducts in their sensing process. This paper presents a review of previously proposed optical oxygen sensor types, materials and formats most applicable to microfluidic cell culture, and analyzes their suitability for this and other in vitro applications. PMID:22163408

  9. Pathobiochemical mechanisms during the acute phase response.

    PubMed

    Kleesiek, K; Greiling, H

    1984-01-01

    The acute phase response is characterised by the following sequence of principle phenomena: (1) an early local inflammatory reaction, (2) formation of inflammatory humoral factors inducing a systemic reaction, (3) stimulation of glycoprotein synthesis predominantly in the hepatocytes, and (4) an increase in the plasma concentration of acute phase proteins, when the rate of biosynthesis exceeds the degradation rate. Inflammatory mediators (lysosomal enzymes, oxygen derived radicals, prostaglandins) are mainly released during phagocytosis by granulocytes and macrophages. The signal reaching the hepatocytes is not yet clearly identified. A leukocyte endogenous mediator (LEM) released by macrophages is described. There is evidence that prostaglandins and probably proteinase alpha 2-macroglobulin complexes are also involved. The hepatic acute phase protein synthesis is modulated by hormones (insulin, cortisol, somatotropin). The biochemical events in the hepatocyte include an increase in protein synthesis and the regulatory control of the glycosylation of polypeptide precursors. The secreted glycoproteins serve variously as inhibitors or mediators of the inflammatory processes. PMID:6208159

  10. Photoacoustic lifetime imaging for direct in vivo tissue oxygen monitoring

    PubMed Central

    Shao, Qi; Ashkenazi, Shai

    2015-01-01

    Abstract. Measuring the partial pressure of oxygen (pO2) in tissue may provide physicians with essential information about the physiological state of tissue. However, currently available methods for measuring or imaging tissue pO2 have significant limitations, preventing them from being widely used in clinics. Recently, we have reported a direct and noninvasive in vivo imaging modality based on the photoacoustic lifetime which overcomes certain drawbacks of the existing methods. The technique maps the excited triplet state of oxygen-sensitive dye, thus reflecting the spatial and temporal distributions of tissue oxygen. Here, we present two studies which apply photoacoustic lifetime imaging (PALI) to monitor changes of tissue oxygen induced by external modulations. The first study modulates tissue oxygen by controlling the percentage of oxygen a normal mouse inhales. We demonstrate that PALI is able to reflect the change in oxygen level with respect to normal, oxygen-rich, and oxygen-poor breathing conditions. The second study involves an acute ischemia model using a thin thread tied around the hindlimb of a normal mouse to reduce the blood flow. PALI images were acquired before, during, and after the restriction. The drop of tissue pO2 and recovery from hypoxia due to reperfusion were tracked and observed by PALI. PMID:25748857

  11. Photoacoustic lifetime imaging for direct in vivo tissue oxygen monitoring

    NASA Astrophysics Data System (ADS)

    Shao, Qi; Ashkenazi, Shai

    2015-03-01

    Measuring the partial pressure of oxygen (pO2) in tissue may provide physicians with essential information about the physiological state of tissue. However, currently available methods for measuring or imaging tissue pO2 have significant limitations, preventing them from being widely used in clinics. Recently, we have reported a direct and noninvasive in vivo imaging modality based on the photoacoustic lifetime which overcomes certain drawbacks of the existing methods. The technique maps the excited triplet state of oxygen-sensitive dye, thus reflecting the spatial and temporal distributions of tissue oxygen. Here, we present two studies which apply photoacoustic lifetime imaging (PALI) to monitor changes of tissue oxygen induced by external modulations. The first study modulates tissue oxygen by controlling the percentage of oxygen a normal mouse inhales. We demonstrate that PALI is able to reflect the change in oxygen level with respect to normal, oxygen-rich, and oxygen-poor breathing conditions. The second study involves an acute ischemia model using a thin thread tied around the hindlimb of a normal mouse to reduce the blood flow. PALI images were acquired before, during, and after the restriction. The drop of tissue pO2 and recovery from hypoxia due to reperfusion were tracked and observed by PALI.

  12. Aircrew oxygen system

    NASA Technical Reports Server (NTRS)

    Babinsky, A. D.; Kiraly, R. J.; Wynveen, R. A.

    1972-01-01

    Closed-loop rebreather system which includes pilot provides oxygen for use in aircraft by safe, reliable method of low weight and size and reduces expense of ground equipment. Water electrolysis generated oxygen is fed into rebreather loop which allows nitrogen elimination and water and carbon dioxide removal.

  13. Oxygen therapy - infants

    MedlinePlus

    ... help breathing than they can get from an oxygen hood or nasal cannula, but do not need a machine to completely ... is not warm enough. Most (but not all) nasal cannulas use cool, dry oxygen. At higher flow rates, this can irritate the ...

  14. Batteries: Avoiding oxygen

    NASA Astrophysics Data System (ADS)

    Hardwick, Laurence J.

    2016-08-01

    In the development of lithium–air batteries, managing the phase change between gaseous oxygen and crystalline lithium peroxide is a key challenge. Now, a high-performing sealed battery with an oxygen anion-redox electrode is presented that does not involve any gas evolution.

  15. Who Needs Oxygen Therapy?

    MedlinePlus

    ... a progressive disease in which damage to the air sacs prevents them from moving enough oxygen into the bloodstream. "Progressive" means the disease gets worse over time. Late-stage heart failure . This is a condition in which the heart can't pump enough oxygen-rich blood to meet the body's ...

  16. Activated platelet chemiluminescence and presence of CD45+ platelets in patients with acute myocardial infarction.

    PubMed

    Gabbasov, Zufar; Ivanova, Oxana; Kogan-Yasny, Victor; Ryzhkova, Evgeniya; Saburova, Olga; Vorobyeva, Inna; Vasilieva, Elena

    2014-01-01

    It has been found that in 15% of acute myocardial infarction patients' platelets generate reactive oxygen species that can be detected with luminol-enhanced chemiluminescence of platelet-rich plasma within 8-10 days after acute myocardial infarction. This increase in generate reactive oxygen species production coincides with the emergence of CD45(+) platelets. The ability of platelets to carry surface leukocyte antigen implies their participation in exchange of specific proteins in the course of acute myocardial infarction. Future studies of CD45(+) platelets in peripheral blood of acute myocardial infarction patients in association with generate reactive oxygen species production may provide a new insight into the complex mechanisms of cell-cell interactions associated with acute myocardial infarction. PMID:24102264

  17. Assessment of tissue oxygenation.

    PubMed

    Robertson, P W; Hart, B B

    1999-06-01

    A continuous supply of oxygen to all tissues is necessary for the efficient production of ATP, and this supply is considered sufficient when aerobic metabolism is maintained. Nonhealing wounds, necrotizing infections, radiation-induced necrosis, crush injury, decompression illness, and CO poisoning all exhibit impaired tissue oxygenation. The need for efficacy of HBO therapy in such conditions is in part determined by the prevailing state of tissue oxygen supply and demand. The methods currently available or under development for assessing the adequacy of tissue oxygenation include blood gas analysis, transcutaneous oxygen measurement, gastric tonometry, pulse oximetry, near-infrared spectroscopy, functional MR imaging, MR spectroscopy, electron paramagnetic resonance, positron emission tomography, and single photon emission computed tomography. The clinical and experimental applications of these methods are discussed and emphasis is placed on their role in hyperbaric medicine. PMID:10333450

  18. 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.

  19. Acute kidney failure

    MedlinePlus

    Kidney failure; Renal failure; Renal failure - acute; ARF; Kidney injury - acute ... There are many possible causes of kidney damage. They include: ... cholesterol (cholesterol emboli) Decreased blood flow due to very ...

  20. Acute arterial occlusion - kidney

    MedlinePlus

    Acute renal arterial thrombosis; Renal artery embolism; Acute renal artery occlusion; Embolism - renal artery ... kidneys need a good blood supply. The main artery to the kidney is called the renal artery. ...

  1. Acute arterial occlusion - kidney

    MedlinePlus

    ... arterial thrombosis; Renal artery embolism; Acute renal artery occlusion; Embolism - renal artery ... often result in permanent kidney failure. Acute arterial occlusion of the renal artery can occur after injury ...

  2. Acute Lymphocytic Leukemia

    MedlinePlus

    ... hard for blood to do its work. In acute lymphocytic leukemia (ALL), also called acute lymphoblastic leukemia, there are too ... of white blood cells called lymphocytes or lymphoblasts. ALL is the most common type of cancer in ...

  3. Hyperspectral sensing of forests

    NASA Astrophysics Data System (ADS)

    Goodenough, David G.; Dyk, Andrew; Chen, Hao; Hobart, Geordie; Niemann, K. Olaf; Richardson, Ash

    2007-11-01

    Canada contains 10% of the world's forests covering an area of 418 million hectares. The sustainable management of these forest resources has become increasingly complex. Hyperspectral remote sensing can provide a wealth of new and improved information products to resource managers to make more informed decisions. Research in this area has demonstrated that hyperspectral remote sensing can be used to create more accurate products for forest inventory, forest health, foliar biochemistry, biomass, and aboveground carbon than are currently available. This paper surveys recent methods and results in hyperspectral sensing of forests and describes space initiatives for hyperspectral sensing.

  4. Advanced Remote Sensing Research

    USGS Publications Warehouse

    Slonecker, Terrence; Jones, John W.; Price, Susan D.; Hogan, Dianna

    2008-01-01

    'Remote sensing' is a generic term for monitoring techniques that collect information without being in physical contact with the object of study. Overhead imagery from aircraft and satellite sensors provides the most common form of remotely sensed data and records the interaction of electromagnetic energy (usually visible light) with matter, such as the Earth's surface. Remotely sensed data are fundamental to geographic science. The Eastern Geographic Science Center (EGSC) of the U.S. Geological Survey (USGS) is currently conducting and promoting the research and development of three different aspects of remote sensing science: spectral analysis, automated orthorectification of historical imagery, and long wave infrared (LWIR) polarimetric imagery (PI).

  5. Optical methods and systems for detecting a constituent in a gas containing oxygen in harsh environments

    DOEpatents

    Carpenter, Michael A.; Sirinakis, George

    2011-01-04

    A method for detecting a gas phase constituent such as carbon monoxide, nitrogen dioxide, hydrogen, or hydrocarbons in a gas comprising oxygen such as air, includes providing a sensing material or film having a metal embedded in a catalytically active matrix such as gold embedded in a yttria stabilized zirconia (YSZ) matrix. The method may include annealing the sensing material at about 900.degree. C., exposing the sensing material and gas to a temperature above 400.degree. C., projecting light onto the sensing material, and detecting a change in the absorption spectrum of the sensing material due to the exposure of the sensing material to the gas in air at the temperature which causes a chemical reaction in the sensing material compared to the absorption spectrum of the sensing material in the absence of the gas. Systems employing such a method are also disclosed.

  6. 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

  7. Oxygen foreshock of Mars

    NASA Astrophysics Data System (ADS)

    Yamauchi, M.; Lundin, R.; Frahm, R. A.; Sauvaud, J.-A.; Holmström, M.; Barabash, S.

    2015-12-01

    Mars Express (MEX) has operated for more than 10 years in the environment of Mars, providing solar wind ion observations from the Analyzer of Space Plasmas and Energetic Atoms experiment's Ion Mass Analyser (IMA). On 21 September 2008, MEX/IMA detected foreshock-like discrete distributions of oxygen ions at around 1 keV in the solar wind attached to the bow shock and this distribution was observed continuously up to more than 2000 km from the bow shock. Foreshock-like protons are also observed but at a shifted location from the oxygen by about 1000 km, at a slightly higher energy, and flowing in a slightly different direction than the oxygen ions. Both protons and oxygen ions are flowing anti-sunward at different angles with respect to the solar wind direction. This is the first time that a substantial amount of planetary oxygen is observed upstream of the bow shock. Although rare, this is not the only IMA observation of foreshock-like oxygen: oxygen ions are sometimes observed for a short period of time (<5 min) inside the foreshock region. These observations suggest a new escape channel for planetary ions through the acceleration in the bow shock-magnetosheath region.

  8. 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.

  9. Acute high-altitude illness: a clinically orientated review

    PubMed Central

    Smedley, Tom

    2013-01-01

    Acute high-altitude illness is an encompassing term for the range of pathology that the unacclimatised individual can develop at increased altitude. This includes acute mountain sickness, high-altitude cerebral oedema and high-altitude pulmonary oedema. These conditions represent an increasing clinical problem as more individuals are exposed to the hypobaric hypoxic environment of high altitude for both work and leisure. In this review of acute high-altitude illness, the epidemiology, risk factors and pathophysiology are explored, before their prevention and treatment are discussed. Appropriate ascent rate remains the most effective acute high-altitude illness prevention, with pharmacological prophylaxis indicated in selected individuals. Descent is the definitive treatment for acute high-altitude illness, with the adjuncts of oxygen and specific drug therapies. PMID:26516505

  10. Land Remote Sensing Overview

    NASA Technical Reports Server (NTRS)

    Byrnes, Ray

    2007-01-01

    A general overview of the USGS land remote sensing program is presented. The contents include: 1) Brief overview of USGS land remote sensing program; 2) Highlights of JACIE work at USGS; 3) Update on NASA/USGS Landsat Data Continuity Mission; and 4) Notes on alternative data sources.

  11. Promote Number Sense

    ERIC Educational Resources Information Center

    Gurganus, Susan

    2004-01-01

    "Number sense" is "an intuition about numbers that is drawn from all varied meanings of number" (NCTM, 1989, p. 39). Students with number sense understand that numbers are representative of objects, magnitudes, relationships, and other attributes; that numbers can be operated on, compared, and used for communication. It is fundamental knowledge…

  12. Remote sensing applications program

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The activities of the Mississippi Remote Sensing Center are described in addition to technology transfer and information dissemination, remote sensing topics such as timber identification, water quality, flood prevention, land use, erosion control, animal habitats, and environmental impact studies are also discussed.

  13. Gravi-sensing microorganisms as model systems for gravity sensing in eukaryotes

    NASA Astrophysics Data System (ADS)

    Streb, C.; Richter, P.; Lebert, M.; Häder, D.-P.

    2001-08-01

    Gravi-sensing in single cells and multicellular organisms is a very active field of investigation. Similarities between gravity sensing mechanisms in uni- and multicellular eukaryotes make single cells ideal model systems for the understanding of gravity responses on the cellular and molecular level with far fetching significance for other systems. This article gives a short overview about gravi-sensing in plants (Arabidopsis, Chara) as well as the ciliates Loxodes and Paramecium and concentrates on gravitaxis research in the single cellular flagellate, Euglena gracilis. Experiments revealed the involvement of cAMP, Ca2+ specific mechanosensitive channels and membrane potential in the signal transduction chain of gravitaxis. Future perspectives for the use of motile, photosynthetic and other unicellular microorganisms for space applications e.g. for oxygen supply in life support systems or research on the origin of life are discussed.

  14. Imaging of Acute Pancreatitis.

    PubMed

    Thoeni, Ruedi F

    2015-11-01

    Acute pancreatitis is an acute inflammation of the pancreas. Several classification systems have been used in the past but were considered unsatisfactory. A revised Atlanta classification of acute pancreatitis was published that assessed the clinical course and severity of disease; divided acute pancreatitis into interstitial edematous pancreatitis and necrotizing pancreatitis; discerned an early phase (first week) from a late phase (after the first week); and focused on systemic inflammatory response syndrome and organ failure. This article focuses on the revised classification of acute pancreatitis, with emphasis on imaging features, particularly on newly-termed fluid collections and implications for the radiologist. PMID:26526433

  15. Plastids and gravitropic sensing

    NASA Technical Reports Server (NTRS)

    Sack, F. D.

    1997-01-01

    Data and theories about the identity of the mass that acts in gravitropic sensing are reviewed. Gravity sensing may have evolved several times in plants and algae in processes such as gravitropism of organs and tip-growing cells, gravimorphism, gravitaxis, and the regulation of cytoplasmic streaming in internodal cells of Chara. In the latter and in gravitaxis, the mass of the entire cell may function in sensing. But gravitropic sensing appears to rely upon the mass of amyloplasts that sediment since (i) the location of cells with sedimentation is highly regulated, (ii) such cells contain other morphological specializations favoring sedimentation, (iii) sedimentation always correlates with gravitropic competence in wild-type plants, (iv) magnetophoretic movement of rootcap amyloplasts mimics gravitropism, and (v) starchless and intermediate starch mutants show reduced gravitropic sensitivity. The simplest interpretation of these data is that gravitropic sensing is plastid-based.

  16. Sensing land pollution.

    NASA Technical Reports Server (NTRS)

    Bowden, L. W.

    1971-01-01

    Land pollution is described in numerous ways by various societies. Pollutants of land are material by-products of human activity and range from environmentally ineffective to positively toxic. The pollution of land by man is centuries old and correlates directly with economy, technology and population. In order to remotely sense land pollution, standards or thresholds must be established. Examples of the potential for sensing land pollution and quality are presented. The technological capabilities for remotely sensed land quality is far advanced over the judgment on how to use the sensed data. Until authoritative and directive decisions on land pollution policy are made, sensing of pollutants will be a random, local and academic affair.

  17. MedlinePlus: Oxygen Therapy

    MedlinePlus

    ... hyperbaric oxygen therapy. It uses oxygen at high pressure to treat wounds and serious infections. NIH: National Heart, Lung, and Blood ... Issues Fires and Burns Involving Home Medical Oxygen (National Fire ...

  18. Oxygen dynamics in photosynthetic membranes.

    NASA Astrophysics Data System (ADS)

    Savikhin, Sergei; Kihara, Shigeharu

    2008-03-01

    Production of oxygen by oxygenic photosynthetic organisms is expected to raise oxygen concentration within their photosynthetic membranes above normal aerobic values. These raised levels of oxygen may affect function of many proteins within photosynthetic cells. However, experiments on proteins in vitro are usually performed in aerobic (or anaerobic) conditions since the oxygen content of a membrane is not known. Using theory of diffusion and measured oxygen production rates we estimated the excess levels of oxygen in functioning photosynthetic cells. We show that for an individual photosynthetic cell suspended in water oxygen level is essentially the same as that for a non-photosynthetic sell. These data suggest that oxygen protection mechanisms may have evolved after the development of oxygenic photosynthesis in primitive bacteria and was driven by the overall rise of oxygen concentration in the atmosphere. Substantially higher levels of oxygen are estimated to occur in closely packed colonies of photosynthetic bacteria and in green leafs.

  19. Acute loss of consciousness.

    PubMed

    Tristán, Bekinschtein; Gleichgerrcht, Ezequiel; Manes, Facundo

    2015-01-01

    Acute loss of consciousness poses a fascinating scenario for theoretical and clinical research. This chapter introduces a simple yet powerful framework to investigate altered states of consciousness. We then explore the different disorders of consciousness that result from acute brain injury, and techniques used in the acute phase to predict clinical outcome in different patient populations in light of models of acute loss of consciousness. We further delve into post-traumatic amnesia as a model for predicting cognitive sequels following acute loss of consciousness. We approach the study of acute loss of consciousness from a theoretical and clinical perspective to conclude that clinicians in acute care centers must incorporate new measurements and techniques besides the classic coma scales in order to assess their patients with loss of consciousness. PMID:25702218

  20. Ultra-sensitive optical oxygen sensors for characterisation of nearly anoxic systems

    PubMed Central

    Lehner, Philipp; Staudinger, Christoph; Borisov, Sergey M.; Klimant, Ingo

    2014-01-01

    Oxygen quantification in trace amounts is essential in many fields of science and technology. Optical oxygen sensors proved invaluable tools for oxygen measurements in a broad concentration range but until now neither optical nor electrochemical oxygen sensors were able to quantify oxygen in the sub-nanomolar concentration range. Herein we present new optical oxygen sensing materials with unmatched sensitivity. They rely on the combination of ultra-long decaying (several hundred milliseconds lifetime) phosphorescent boron- and aluminium-chelates and highly oxygen-permeable and chemically stable perfluorinated polymers. The sensitivity of the new sensors is improved up to 20-fold compared to state-of-the-art analogues. The limits of detection are as low as 5 parts per billion, volume in gas phase under atmospheric pressure or 7 picomolar in solution. The sensors enable completely new applications for monitoring of oxygen in previously inaccessible concentration ranges. PMID:25042041