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Sample records for oxygen consumption vo2peak

  1. Effects of daily activity recorded by pedometer on peak oxygen consumption (VO2peak), ventilatory threshold and leg extension power in 30- to 69-year-old Japanese without exercise habit.

    Science.gov (United States)

    Zhang, Jian-Guo; Ohta, Toshiki; Ishikawa-Takata, Kazuko; Tabata, Izumi; Miyashita, Mitsumasa

    2003-09-01

    The relationships among walk steps, exercise habits and peak oxygen consumption (VO2peak), ventilatory threshold (VT) and leg extension power (LEP) were examined in 709 apparently healthy Japanese subjects (male 372, female 337) aged 30-69 years. Walk steps were evaluated using a pedometer. VO2peak and VT were assessed by a cycle ergometer test, while LEP was measured with an isokinetic leg extension system (Combi, Anaero Press 3500, Japan). Subjects who participated in exercise three times or more a week demonstrated significantly greater VO2peak and VT when compared with subjects without exercise habits. When a separate analysis was conducted on subjects who exercised fewer than three times per week, we found that the subgroup with the highest number of walk steps showed significantly greater VT in all male subjects and female subjects aged 30-49 years, but a significantly greater VO2peak only in females aged 30-49 years, when compared to the subgroup with the fewest walk steps. These results suggest that although some people exercise less than three times a week, if they are quite active in daily life, such activities might also confer benefits upon their fitness.

  2. Oxygen uptake efficiency slope and peak oxygen consumption predict prognosis in children with tetralogy of Fallot.

    Science.gov (United States)

    Tsai, Yun-Jeng; Li, Min-Hui; Tsai, Wan-Jung; Tuan, Sheng-Hui; Liao, Tin-Yun; Lin, Ko-Long

    2016-07-01

    Oxygen uptake efficiency slope (OUES) and peak oxygen consumption (VO2peak) are exercise parameters that can predict cardiac morbidity in patients with numerous heart diseases. But the predictive value in patients with tetralogy of Fallot is still undetermined, especially in children. We evaluated the prognostic value of OUES and VO2peak in children with total repair of tetralogy of Fallot. Retrospective cohort study. Forty tetralogy of Fallot patients younger than 12 years old were recruited. They underwent a cardiopulmonary exercise test during the follow-up period after total repair surgery. The results of the cardiopulmonary exercise test were used to predict the cardiac related hospitalization in the following two years after the test. OUES normalized by body surface area (OUES/BSA) and the percentage of predicted VO2peak appeared to be predictive for two-year cardiac related hospitalization. Receiver operating characteristic curve analysis demonstrated that the best threshold value for OUES/BSA was 1.029 (area under the curve = 0.70, p = 0.03), and for VO2peak was 74% of age prediction (area under the curve = 0.72, p = 0.02). The aforementioned findings were confirmed by Kaplan-Meier plots and log-rank test. OUES/BSA and VO2peak are useful predictors of cardiac-related hospitalization in children with total repair of tetralogy of Fallot. © The European Society of Cardiology 2015.

  3. Body fat, abdominal fat and body fat distribution related to VO(2PEAK) in young children

    DEFF Research Database (Denmark)

    Dencker, Magnus; Wollmer, Per; Karlsson, Magnus K

    2011-01-01

    as a percentage of body mass (BF%) and body fat distribution as AFM/TBF. VO(2PEAK) was assessed by indirect calorimetry during maximal exercise test. Results. Significant relationships existed between body fat measurements and VO(2PEAK) in both boys and girls, with Pearson correlation coefficients for absolute...

  4. Predictors of VO2Peak in children age 6- to 7-years-old

    DEFF Research Database (Denmark)

    Dencker, Magnus; Hermansen, Bianca; Bugge, Anna

    2011-01-01

    This study investigated the predictors of aerobic fitness (VO2PEAK) in young children on a population-base. Participants were 436 children (229 boys and 207 girls) aged 6.7 ± 0.4 yrs. VO2PEAK was measured during a maximal treadmill exercise test. Physical activity was assessed by accelerometers....... Total body fat and total fat free mass were estimated from skinfold measurements. Regression analyses indicated that significant predictors for VO2PEAK per kilogram body mass were total body fat, maximal heart rate, sex, and age. Physical activity explained an additional 4-7%. Further analyses showed...... the main contributing factors for absolute values of VO2PEAK were fat free mass, maximal heart rate, sex, and age. Physical activity explained an additional 3-6%....

  5. [Oxygen peak consumption is a better predictor of cardiovascular risk than handgrip strength in older Chilean women].

    Science.gov (United States)

    Farías-Valenzuela, Claudio; Pérez-Luco, Cristian; Ramírez-Campillo, Rodrigo; Álvarez, Cristian; Castro-Sepúlveda, Mauricio

    Handgrip strength (HS) and peak oxygen consumption (Vo2peak) are powerful predictors of cardiovascular risk, although it is unknown which of the two variables is the better predictor. The objective of the following study was to relate HS and Vo2peak to cardiovascular risk markers in older Chilean women. Physically active adult women (n=51; age, 69±4.7years) participated in this study. The HS and Vo2peak were evaluated and related to the anthropometric variables of body mass, body mass index (BMI), waist circumference (WC), hip circumference (HC), waist ratio (WR), and waist height ratio (WHR), as well as with the cardiovascular variables systolic (SBP) and diastolic (DBP) and cardiac recovery in one minute (RHR1). A multilinear regression model was used for the analysis of the associated variables (Pcardiovascular risk markers associated (Pcardiovascular risk markers, Vo2peak offers greater associative power with these cardiovascular risk factors. Copyright © 2017 SEGG. Publicado por Elsevier España, S.L.U. All rights reserved.

  6. Aerobic fitness and metabolic health in children: A clinical validation of directly measured maximal oxygen consumption versus performance measures as markers of health.

    Science.gov (United States)

    Aadland, Eivind; Kvalheim, Olav Martin; Rajalahti, Tarja; Skrede, Turid; Resaland, Geir Kåre

    2017-09-01

    High aerobic fitness is consistently associated with a favorable metabolic health profile in children. However, measurement of oxygen uptake, regarded as the gold standard for evaluating aerobic fitness, is often not feasible. Thus, the aim of the present study was to perform a clinical validation of three measures of aerobic fitness (peak oxygen consumption [VO 2peak ] and time to exhaustion [TTE] determined from a graded treadmill protocol to exhaustion, and the Andersen intermittent running test) with clustered metabolic health in 10-year-old children. We included 93 children (55 boys and 38 girls) from Norway during 2012-2013 in the study. Associations between aerobic fitness and three different composite metabolic health scores (including lipoprotein subgroup particle concentrations, triglyceride, glucose, systolic blood pressure, and waist-to-height ratio) were determined by regression analyses adjusting for sex. The relationships among the measures of aerobic fitness were r  = 0.78 for VO 2peak vs. TTE, r  = 0.63 for VO 2peak vs. the Andersen test, and r  = 0.67 for TTE vs. the Andersen test. The Andersen test showed the strongest associations across all markers of metabolic health ( r  = - 0.45 to - 0.31, p  fitness do not stand back as markers of metabolic health status in children, compared to VO 2peak . This is of great importance as good field tests provide opportunities for measuring aerobic fitness in many settings where measuring VO 2peak are impossible.

  7. High-intensity interval training improves VO2peak, maximal lactate accumulation, time trial and competition performance in 9?11-year-old swimmers

    OpenAIRE

    Sperlich, Billy; Zinner, Christoph; Heilemann, Ilka; Kjendlie, Per-Ludvik; Holmberg, Hans-Christer; Mester, Joachim

    2010-01-01

    Training volume in swimming is usually very high when compared to the relatively short competition time. High-intensity interval training (HIIT) has been demonstrated to improve performance in a relatively short training period. The main purpose of the present study was to examine the effects of a 5-week HIIT versus high-volume training (HVT) in 9?11-year-old swimmers on competition performance, 100 and 2,000?m time (T 100?m and T 2,000?m), VO2peak and rate of maximal lactate accumulation (La...

  8. Escala de VO2pico em adolescentes obesos e não-Obesos por diferentes métodos Escala de VO2pico en adolescentes obesos y no obesos por diferentes métodos Scale of VO2peak in obese and non-obese adolescents by different methods

    Directory of Open Access Journals (Sweden)

    Gerusa Eisfeld Milano

    2009-12-01

    estrategia atractiva para comparar individuos con grandes diferencias en la masa corporal. OBJETIVO: Investigar el VO2pico en individuos obesos y no obesos usando el método de corrección de masa corporal (convencional y la escala alométrica (método alométrico y cómo esos métodos se aplican cuando individuos de ambos sexos se ejercitan en una cinta ergométrica. MÉTODOS: El VO2pico relativo al peso corporal y por el método alométrico fue comparado en 54 adolescentes obesos y 33 no obesos (10-16 años. Para evaluar el VO2pico durante un test máximo se utilizó calorimetría indirecta. El exponente alométrico fue calculado considerando la masa corporal individual. Así, el VO2pico fue corregido mediante el exponente alométrico. Las comparaciones se realizaron utilizando two-way ANOVA para medidas repetidas (p0,05. Sin embargo, el VO2pico calculado por el método convencional fue mayor (p0.05 entre los grupos. CONCLUSIÓN: Los individuos obesos presentaron VO2pico más bajo que los no obesos, al ser evaluados mediante el método convencional. Sin embargo, las diferencias desaparecieron cuando se aplicó el método de la escala alométrica.BACKGROUND: Peak oxygen uptake (VO2peak can be defined as the highest oxygen rate consumed during exhaustive or maximal exercise. The evaluation of the aerobic fitness can be expressed as relative to body mass, but this procedure may not fully remove differences when heavy subjects are assessed. Thus, the allometric scaling procedure is an attractive strategy to compare individuals with large differences in body mass. OBJECTIVE: Investigate VO2peak in obese and non-obese individuals using body mass correction (conventional and allometric scaling (allometric methods and how these methods apply when subjects of different genders exercise on a treadmill. METHODS: VO2peak relative to body weight and measured by the allometric method were compared in 54 obese and 33 non-obese adolescents (10 a 16 years. Indirect calorimetry was used to

  9. Allometric modelling of peak oxygen uptake in male soccer players of 8-18 years of age

    NARCIS (Netherlands)

    Valente-dos-Santos, Joao; Coelho-e-Silva, Manuel J.; Tavares, Oscar M.; Brito, Joao; Seabra, Andre; Rebelo, Antonio; Sherar, Lauren B.; Elferink-Gemser, Marije T.; Malina, Robert M.

    Background: Peak oxygen uptake (VO2peak) is routinely scaled as mL O-2 per kilogram body mass despite theoretical and statistical limitations of using ratios. Aim: To examine the contribution of maturity status and body size descriptors to ageassociated inter-individual variability in VO2peak and to

  10. Measurement of forearm oxygen consumption

    DEFF Research Database (Denmark)

    Astrup, A; Simonsen, L; Bülow, J

    1988-01-01

    The classical forearm technique widely used for studies of skeletal muscle metabolism requires arterial cannulation. To avoid arterial puncture it is becoming more common to arterialize blood from a contralateral hand vein by local heating. This modification and the classical method have produced...... blood flow and decreases skeletal muscle blood flow. This facilitates mixing of superficial blood with deep venous blood. Contralateral heating increased deep venous oxygen saturation and abolished the pronounced glucose-induced increase in oxygen consumption observed in the control experiments after...... contradictory results regarding the contribution of skeletal muscle to glucose-induced thermogenesis. The effect on forearm circulation and the metabolism of heating the contralateral hand was examined before and after an oral glucose load. The results suggest that contralateral heating increases subcutaneous...

  11. A prospective population study of resting heart rate and peak oxygen uptake (the HUNT Study, Norway.

    Directory of Open Access Journals (Sweden)

    Javaid Nauman

    Full Text Available OBJECTIVES: We assessed the prospective association of resting heart rate (RHR at baseline with peak oxygen uptake (VO(2peak 23 years later, and evaluated whether physical activity (PA could modify this association. BACKGROUND: Both RHR and VO(2peak are strong and independent predictors of cardiovascular morbidity and mortality. However, the association of RHR with VO(2peak and modifying effect of PA have not been prospectively assessed in population studies. METHODS: In 807 men and 810 women free from cardiovascular disease both at baseline (1984-86 and follow-up 23 years later, RHR was recorded at both occasions, and VO(2peak was measured by ergospirometry at follow-up. We used Generalized Linear Models to assess the association of baseline RHR with VO(2peak, and to study combined effects of RHR and self-reported PA on later VO(2peak. RESULTS: There was an inverse association of RHR at baseline with VO(2peak (p<0.01. Men and women with baseline RHR greater than 80 bpm had 4.6 mL.kg(-1.min(-1 (95% confidence interval [CI], 2.8 to 6.3 and 1.4 mL.kg(-1.min(-1 (95% CI, -0.4 to 3.1 lower VO(2peak at follow-up compared with men and women with RHR below 60 bpm at baseline. We found a linear association of change in RHR with VO(2peak (p=0.03, suggesting that a decrease in RHR over time is likely to be beneficial for cardiovascular fitness. Participants with low RHR and high PA at baseline had higher VO(2peak than inactive people with relatively high RHR. However, among participants with relatively high RHR and high PA at baseline, VO(2peak was similar to inactive people with relatively low RHR. CONCLUSION: RHR is an important predictor of VO(2peak, and serial assessments of RHR may provide useful and inexpensive information on cardiovascular fitness. The results suggest that high levels of PA may compensate for the lower VO(2peak associated with a high RHR.

  12. Changes in Peak Oxygen Uptake and Plasma Volume in Fit and Unfit Subjects Following Exposure to a Simulation of Microgravity

    National Research Council Canada - National Science Library

    Convertino, Victor

    1997-01-01

    To test the hypothesis that the magnitude of reduction in plasma volume and work capacity following exposure to simulated microgravity is dependent on the initial level of aerobic fitness, peak oxygen uptake (VO2peak...

  13. Oscillation of tissue oxygen index in non-exercising muscle during exercise.

    Science.gov (United States)

    Yano, T; Afroundeh, R; Shirakawa, K; Lian, C-S; Shibata, K; Xiao, Z; Yunoki, T

    2015-09-01

    The purpose of the present study was to examine how oscillation of tissue oxygen index (TOI) in non-exercising exercise is affected during high-intensity and low-intensity exercises. Three exercises were performed with exercise intensities of 30% and 70% peak oxygen uptake (Vo(2)peak) for 12 min and with exercise intensity of 70% Vo(2)peak for 30 s. TOI in non-exercising muscle (biceps brachii) during the exercises for 12 min was determined by nearinfrared spectroscopy. TOI in the non-exercising muscle during the exercises was analyzed by fast Fourier transform (FFT) to obtain power spectra density (PSD). The frequency at which maximal PSD appeared (Fmax) during the exercise with 70% Vo(2)peak for 12 min (0.00477 ± 0.00172 Hz) was significantly lower than that during the exercise with 30% Vo2peak for 12 min (0.00781 ± 0.00338 Hz). There were significant differences in blood pH and blood lactate between the exercise with 70% Vo(2)peak and the exercise with 30% Vo(2)peak. It is concluded that TOI in nonexercising muscle oscillates during low-intensity exercise as well as during high-intensity exercise and that the difference in Fmax between the two exercises is associated with the difference in increase in blood lactate derived from the exercise.

  14. Arm Crank and Wheelchair Ergometry Produce Similar Peak Oxygen Uptake but Different Work Economy Values in Individuals with Spinal Cord Injury

    Directory of Open Access Journals (Sweden)

    Tom Tørhaug

    2016-01-01

    Full Text Available Objective. To study whether values for peak oxygen uptake (VO2peak and work economy (WE at a standardized workload are different when tested by arm crank ergometry (ACE and wheelchair ergometry (WCE. Methods. Twelve paraplegic men with spinal cord injury (SCI in stable neurological condition participated in this cross-sectional repeated-measures study. We determined VO2peak and peak power output (POpeak values during ACE and WCE in a work-matched protocol. Work economy was tested at a standardized workload of 30 Watts (W for both ACE and WCE. Results. There were no significant differences in VO2peak (mL·kg−1·min−1 between ACE (27.3±3.2 and WCE (27.4±3.8 trials, and a Bland-Altman plot shows that findings are within 95% level of agreement. WE or oxygen consumption at 30 W (VO2-30W was significantly lower during WCE compared to ACE (P<0.039. Mean (95% CI POpeak (W were 130 (111–138 and 100 (83–110 during ACE and WCE, respectively. Conclusion. The findings in the present study support the use of both ACE and WCE for testing peak oxygen uptake. However, WE differed between the two test modalities, meaning that less total energy is used to perform external work of 30 W during wheelchair exercise when using this WCE (VP100 Handisport ergometer. Clinical Trials Protocol Record is NCT00987155/4.2007.2271.

  15. Physical activity as a long-term predictor of peak oxygen uptake: the HUNT Study.

    Science.gov (United States)

    Aspenes, Stian Thoresen; Nauman, Javaid; Nilsen, Tom Ivar Lund; Vatten, Lars Johan; Wisløff, Ulrik

    2011-09-01

    A physically active lifestyle and a relatively high level of cardiorespiratory fitness are important for longevity and long-term health. No population-based study has prospectively assessed the association of physical activity levels with long-term peak oxygen uptake (VO(2peak)). 1843 individuals (906 women and 937 men) who were between 18 and 66 yr at baseline and were free from known lung or heart diseases at both baseline (1984-1986) and follow-up (2006-2008) were included in the study. Self-reported physical activity was recorded at both occasions, and VO(2peak) was measured at follow-up. The association of physical activity levels and VO(2peak) was adjusted for age, level of education, smoking status, and weight change from baseline to follow-up, using ANCOVA statistics. The level of physical activity at baseline was strongly associated with VO(2peak) at follow-up 23 yr later in both men and women (Ptrends active at baseline had higher (3.3 and 4.6 mL·kg(-1)·min(-1)) VO(2peak) at follow-up. Women who were inactive at baseline but highly active at follow-up had 3.7 mL·kg(-1)·min(-1) higher VO(2peak) compared with women who were inactive both at baseline and at follow-up. The corresponding comparison in men showed a difference of 5.2 mL·kg(-1)·min(-1) (95% confidence interval = 3.1-7.3) in VO(2peak). Physical activity level at baseline was positively associated with directly measured cardiorespiratory fitness (VO(2peak)) 23 yr later. People who changed from low to high activity during the observation period had substantially higher V˙O(2peak) at follow-up compared with people whose activity remained low.

  16. Peak oxygen uptake in Paralympic sitting sports: A systematic literature review, meta- and pooled-data analysis.

    Science.gov (United States)

    Baumgart, Julia Kathrin; Brurok, Berit; Sandbakk, Øyvind

    2018-01-01

    Peak oxygen uptake (VO2peak) in Paralympic sitting sports athletes represents their maximal ability to deliver energy aerobically in an upper-body mode, with values being influenced by sex, disability-related physiological limitations, sport-specific demands, training status and how they are tested. To identify VO2peak values in Paralympic sitting sports, examine between-sports differences and within-sports variations in VO2peak and determine the influence of sex, age, body-mass, disability and test-mode on VO2peak. Systematic literature review and meta-analysis. PubMed, CINAHL, SPORTDiscusTM and EMBASE were systematically searched in October 2016 using relevant medical subject headings, keywords and a Boolean. Studies that assessed VO2peak values in sitting sports athletes with a disability in a laboratory setting were included. Data was extracted and pooled in the different sports disciplines, weighted by the Dersimonian and Laird random effects approach. Quality of the included studies was assessed with a modified version of the Downs and Black checklist by two independent reviewers. Meta-regression and pooled-data multiple regression analyses were performed to assess the influence of sex, age, body-mass, disability, test mode and study quality on VO2peak. Of 6542 retrieved articles, 57 studies reporting VO2peak values in 14 different sitting sports were included in this review. VO2peak values from 771 athletes were used in the data analysis, of which 30% participated in wheelchair basketball, 27% in wheelchair racing, 15% in wheelchair rugby and the remaining 28% in the 11 other disciplines. Fifty-six percent of the athletes had a spinal cord injury and 87% were men. Sports-discipline-averaged VO2peak values ranged from 2.9 L∙min-1 and 45.6 mL∙kg-1∙min-1 in Nordic sit skiing to 1.4 L∙min-1 and 17.3 mL∙kg-1∙min-1 in shooting and 1.3 L∙min-1 and 18.9 mL∙kg-1∙min-1 in wheelchair rugby. Large within-sports variation was found in sports with few

  17. Peak oxygen uptake in Paralympic sitting sports: A systematic literature review, meta- and pooled-data analysis.

    Directory of Open Access Journals (Sweden)

    Julia Kathrin Baumgart

    Full Text Available Peak oxygen uptake (VO2peak in Paralympic sitting sports athletes represents their maximal ability to deliver energy aerobically in an upper-body mode, with values being influenced by sex, disability-related physiological limitations, sport-specific demands, training status and how they are tested.To identify VO2peak values in Paralympic sitting sports, examine between-sports differences and within-sports variations in VO2peak and determine the influence of sex, age, body-mass, disability and test-mode on VO2peak.Systematic literature review and meta-analysis.PubMed, CINAHL, SPORTDiscusTM and EMBASE were systematically searched in October 2016 using relevant medical subject headings, keywords and a Boolean.Studies that assessed VO2peak values in sitting sports athletes with a disability in a laboratory setting were included.Data was extracted and pooled in the different sports disciplines, weighted by the Dersimonian and Laird random effects approach. Quality of the included studies was assessed with a modified version of the Downs and Black checklist by two independent reviewers. Meta-regression and pooled-data multiple regression analyses were performed to assess the influence of sex, age, body-mass, disability, test mode and study quality on VO2peak.Of 6542 retrieved articles, 57 studies reporting VO2peak values in 14 different sitting sports were included in this review. VO2peak values from 771 athletes were used in the data analysis, of which 30% participated in wheelchair basketball, 27% in wheelchair racing, 15% in wheelchair rugby and the remaining 28% in the 11 other disciplines. Fifty-six percent of the athletes had a spinal cord injury and 87% were men. Sports-discipline-averaged VO2peak values ranged from 2.9 L∙min-1 and 45.6 mL∙kg-1∙min-1 in Nordic sit skiing to 1.4 L∙min-1 and 17.3 mL∙kg-1∙min-1 in shooting and 1.3 L∙min-1 and 18.9 mL∙kg-1∙min-1 in wheelchair rugby. Large within-sports variation was found in

  18. Peak oxygen uptake in Paralympic sitting sports: A systematic literature review, meta- and pooled-data analysis

    Science.gov (United States)

    Brurok, Berit; Sandbakk, Øyvind

    2018-01-01

    Background Peak oxygen uptake (VO2peak) in Paralympic sitting sports athletes represents their maximal ability to deliver energy aerobically in an upper-body mode, with values being influenced by sex, disability-related physiological limitations, sport-specific demands, training status and how they are tested. Objectives To identify VO2peak values in Paralympic sitting sports, examine between-sports differences and within-sports variations in VO2peak and determine the influence of sex, age, body-mass, disability and test-mode on VO2peak. Design Systematic literature review and meta-analysis. Data sources PubMed, CINAHL, SPORTDiscusTM and EMBASE were systematically searched in October 2016 using relevant medical subject headings, keywords and a Boolean. Eligibility criteria Studies that assessed VO2peak values in sitting sports athletes with a disability in a laboratory setting were included. Data synthesis Data was extracted and pooled in the different sports disciplines, weighted by the Dersimonian and Laird random effects approach. Quality of the included studies was assessed with a modified version of the Downs and Black checklist by two independent reviewers. Meta-regression and pooled-data multiple regression analyses were performed to assess the influence of sex, age, body-mass, disability, test mode and study quality on VO2peak. Results Of 6542 retrieved articles, 57 studies reporting VO2peak values in 14 different sitting sports were included in this review. VO2peak values from 771 athletes were used in the data analysis, of which 30% participated in wheelchair basketball, 27% in wheelchair racing, 15% in wheelchair rugby and the remaining 28% in the 11 other disciplines. Fifty-six percent of the athletes had a spinal cord injury and 87% were men. Sports-discipline-averaged VO2peak values ranged from 2.9 L∙min-1 and 45.6 mL∙kg-1∙min-1 in Nordic sit skiing to 1.4 L∙min-1 and 17.3 mL∙kg-1∙min-1 in shooting and 1.3 L∙min-1 and 18.9 mL∙kg-1

  19. Cardiorespiratory Responses and Prediction of Peak Oxygen Uptake during the Shuttle Walking Test in Healthy Sedentary Adult Men

    Science.gov (United States)

    Neves, Camila D. C.; Lacerda, Ana Cristina Rodrigues; Lage, Vanessa K. S.; Lima, Liliana P.; Fonseca, Sueli F.; de Avelar, Núbia C. P.; Teixeira, Mauro M.; Mendonça, Vanessa A.

    2015-01-01

    Background The application of the Shuttle Walking Test (SWT) to assess cardiorespiratory fitness and the intensity of this test in healthy participants has rarely been studied. This study aimed to assess and correlate the cardiorespiratory responses of the SWT with the cardiopulmonary exercise testing (CEPT) and to develop a regression equation for the prediction of peak oxygen uptake (VO2 peak) in healthy sedentary adult men. Methods In the first stage of this study, 12 participants underwent the SWT and the CEPT on a treadmill. In the second stage, 53 participants underwent the SWT twice. In both phases, the VO2 peak, respiratory exchange ratio (R), and heart rate (HR) were evaluated. Results Similar results in VO2 peak (P>0.05), R peak (P>0.05) and predicted maximum HR (P>0.05) were obtained between the SWT and CEPT. Both tests showed strong and significant correlations of VO2 peak (r = 0.704, P = 0.01) and R peak (r = 0.737, P0.05) was found. Conclusions The SWT produced maximal cardiorespiratory responses comparable to the CEPT, and the developed equation showed viability for the prediction of VO2 peak in healthy sedentary men. PMID:25659094

  20. [The oxygen consumption of ostrich embryos during incubation].

    Science.gov (United States)

    Reiner, G; Dzapo, V

    1995-02-01

    This work deals with the oxygen consumption of ostrich chicks during incubation. Brood eggs were incubated in a hermetic isolated acrylic-glass cylinder. Reduction of oxygen content in the air surrounding the egg was measured using an oxygen-sensitive electrode. A sigmoid curve could be drawn during incubation, with the steepest phase being around day 26. Maximum oxygen consumption was reached on day 36. It was slightly decreased until day 39, when the embryo switches to lung circulation, followed again by an increase until hatching. Average oxygen consumptions for the whole brood interval were calculated to 63.6 liters. Oxygen volumes consumed on day 36 result in a demand about to 240 liters of fresh air per egg and day. Oxygen consumption of the embryos on day 36 was significantly positive correlated with their vitality. Numb or less vital embryos could be clearly differentiated from others. The higher a chick's oxygen consumption, the earlier and shorter its hatching. Possible applications of the method in regard to the evaluation of incubation parameters or chicken constitution are discussed.

  1. Submaximal oxygen uptake kinetics, functional mobility, and physical activity in older adults with heart failure and reduced ejection fraction.

    Science.gov (United States)

    Hummel, Scott L; Herald, John; Alpert, Craig; Gretebeck, Kimberlee A; Champoux, Wendy S; Dengel, Donald R; Vaitkevicius, Peter V; Alexander, Neil B

    2016-07-01

    Submaximal oxygen uptake measures are more feasible and may better predict clinical cardiac outcomes than maximal tests in older adults with heart failure (HF). We examined relationships between maximal oxygen uptake, submaximal oxygen kinetics, functional mobility, and physical activity in older adults with HF and reduced ejection fraction. Older adults with HF and reduced ejection fraction (n = 25, age 75 ± 7 years) were compared to 25 healthy age- and gender-matched controls. Assessments included a maximal treadmill test for peak oxygen uptake (VO2peak), oxygen uptake kinetics at onset of and on recovery from a submaximal treadmill test, functional mobility testing [Get Up and Go (GUG), Comfortable Gait Speed (CGS), Unipedal Stance (US)], and self-reported physical activity (PA). Compared to controls, HF had worse performance on GUG, CGS, and US, greater delays in submaximal oxygen uptake kinetics, and lower PA. In controls, VO2peak was more strongly associated with functional mobility and PA than submaximal oxygen uptake kinetics. In HF patients, submaximal oxygen uptake kinetics were similarly associated with GUG and CGS as VO2peak, but weakly associated with PA. Based on their mobility performance, older HF patients with reduced ejection fraction are at risk for adverse functional outcomes. In this population, submaximal oxygen uptake measures may be equivalent to VO2 peak in predicting functional mobility, and in addition to being more feasible, may provide better insight into how aerobic function relates to mobility in older adults with HF.

  2. Influence of substrate composition on vitro oxygen consumption of ...

    African Journals Online (AJOL)

    The endogenous oxygen consumption of lung, liver and spleen slices is only slightly increased by glucose in an SRP medium compared with its effect on heart and kidney slices. Individual substrates which induced a highly significant increase in oxygen uptake of lung tissue were succinate, acetate, pyruvate and glucose, ...

  3. Apparatus for the automatic determination of oxygen consumption in ...

    African Journals Online (AJOL)

    An apparatus is described which permits the automatic determination of the oxygen consumption of three fish and a control for 24 hours per day. This is made possible by an electrical control system operating four three-way valves which allow water from one of four respiration chambers at a time to flow past an oxygen ...

  4. Single Cell Oxygen Mapping (SCOM) by Scanning Electrochemical Microscopy Uncovers Heterogeneous Intracellular Oxygen Consumption

    OpenAIRE

    Santos, Carla Santana; Kowaltowski, Alicia J.; Bertotti, Mauro

    2017-01-01

    We developed a highly sensitive oxygen consumption scanning microscopy system using platinized platinum disc microelectrodes. The system is capable of reliably detecting single-cell respiration, responding to classical regulators of mitochondrial oxygen consumption activity as expected. Comparisons with commercial multi-cell oxygen detection systems show that the system has comparable errors (if not smaller), with the advantage of being able to monitor inter and intra-cell heterogeneity in ox...

  5. Feed intake and oxygen consumption in fish

    NARCIS (Netherlands)

    Subramanian, S.

    2013-01-01

    In fish, the voluntary feed intake is influenced by dietary, environmental and/or physiological factors. It is well known that under hypoxia the concentration of oxygen in the water (DO) determines the feed intake of fish. However at non-limiting water DO levels (normoxia), several other

  6. Sources of variation in oxygen consumption of aquatic animals demonstrated by simulated constant oxygen consumption and respirometers of different sizes

    DEFF Research Database (Denmark)

    Svendsen, Morten Bo Søndergaard; Bushnell, P.G.; Christensen, Emil Aputsiaq Flindt

    2016-01-01

    As intermittent-flow respirometry has become a common method for the determination of resting metabolism or standard metabolic rate (SMR), this study investigated how much of the variability seen in the experiments was due to measurement error. Experiments simulated different constant oxygen cons...... oxygen consumption rates of fishes in systems with reasonable RFRs mainly comes from the animal, not from the measuring equipment....

  7. Circadian rhythm of energy expenditure and oxygen consumption.

    Science.gov (United States)

    Leuck, Marlene; Levandovski, Rosa; Harb, Ana; Quiles, Caroline; Hidalgo, Maria Paz

    2014-02-01

    This study aimed to evaluate the effect of continuous and intermittent methods of enteral nutrition (EN) administration on circadian rhythm. Thirty-four individuals, aged between 52 and 80 years, were fed through a nasoenteric tube. Fifteen individuals received a continuous infusion for 24 hours/d, and 19 received an intermittent infusion in comparable quantities, every 4 hours from 8:00 to 20:00. In each patient, 4 indirect calorimetric measurements were carried out over 24 hours (A: 7:30, B: 10:30, C: 14:30, and D: 21:30) for 3 days. Energy expenditure and oxygen consumption were significantly higher in the intermittent group than in the continuous group (1782 ± 862 vs 1478 ± 817 kcal/24 hours, P = .05; 257 125 vs 212 117 ml/min, P = .048, respectively). The intermittent group had higher levels of energy expenditure and oxygen consumption at all the measured time points compared with the continuous group. energy expenditure and oxygen consumption in both groups were significantly different throughout the day for 3 days. There is circadian rhythm variation of energy expenditure and oxygen consumption with continuous and intermittent infusion for EN. This suggests that only one indirect daily calorimetric measurement is not able to show the patient's true needs. Energy expenditure is higher at night with both food administration methods. Moreover, energy expenditure and oxygen consumption are higher with the intermittent administration method at all times.

  8. Relation of oxygen uptake to work rate in prepubertal healthy children - reference for VO2/W-slope and effect on cardiorespiratory fitness assessment.

    Science.gov (United States)

    Tompuri, Tuomo; Lintu, Niina; Laitinen, Tomi; Lakka, Timo A

    2017-08-09

    Exercise testing by cycle ergometer allows to observe the interaction between oxygen uptake (VO 2 ) and workload (W), and VO 2 /W-slope can be used as a diagnostic tool. Respectively, peak oxygen uptake (VO 2 PEAK ) can be estimated by maximal workload. We aim to determine reference for VO 2 /W-slope among prepubertal children and define agreement between estimated and measured VO 2 PEAK . A total of 38 prepubertal children (20 girls) performed a maximal cycle ergometer test with respiratory gas analysis. VO 2 /W-slopes were computed using linear regression. Agreement analysis by Bland and Altman for estimated and measured VO 2 PEAK was carried out including limits of agreement (LA). Determinants for VO 2 /W-slopes and estimation bias were defined. VO2/W-slope was in both girls and boys ≥9·4 and did not change with exercise level, but the oxygen cost of exercise was higher among physically more active children. Estimated VO 2 PEAK had 6·4% coefficient of variation, and LA varied from 13% underestimation to 13% overestimation. Bias had a trend towards underestimation along lean mass proportional VO 2 PEAK . The primary determinant for estimation bias was VO2/W-slope (β = -0·65; PW-slope among healthy prepubertal children were similar to those published for adults and among adolescents. Estimated and measured VO 2 PEAK should not be considered to be interchangeable because of the variation in the relationship between VO 2 and W. On other hand, variation in the relationship between VO 2 and W enables that VO 2 /W-slope can be used as a diagnostic tool. © 2017 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  9. Oxygen consumption by sticklebacks (Gasterosteus aculeatus L. ) exposed to zinc

    Energy Technology Data Exchange (ETDEWEB)

    Brafield, A.E.; Matthiessen, P.

    1976-10-01

    The rate of oxygen consumption by sticklebacks has been studied by long-term continuous-flow respirometry. Exposure to 1 ppM zinc in calcium-free water causes wide variations in individual responses, but oxygen uptake tends to rise and then become extremely erratic, before declining as death approaches. Behavioural abnormalities such as increased ventilation rate, loss of balance, and long periods of inactivity alternating with spasmodic swimming also occur. Exposure to 6.5 ppM zinc in high-calcium water generally causes a rise in oxygen consumption, followed by fluctuations in the rate of uptake, but no behavioural abnormalities occur and deaths are rare even after exposure for 400 h. If restored to zinc-free water after 40 h exposure to zinc, recovery is generally complete, although fluctuating rates of oxygen uptake persist. These results are discussed in relation to previous work on the effects of heavy metals on fish respiration.

  10. Renal transplantation induces mitochondrial uncoupling, increased kidney oxygen consumption, and decreased kidney oxygen tension

    NARCIS (Netherlands)

    Papazova, Diana A.; Friederich-Persson, Malou; Joles, Jaap A.; Verhaar, Marianne C.

    2015-01-01

    Hypoxia is an acknowledged pathway to renal injury and ischemia-reperfusion (I/R) and is known to reduce renal oxygen tension (PO2). We hypothesized that renal I/R increases oxidative damage and induces mitochondrial uncoupling, resulting in increased oxygen consumption and hence kidney

  11. Estimation of peak oxygen uptake from maximal power output among 9-10 year-old children in Lhasa, Tibet

    DEFF Research Database (Denmark)

    Bianba, B; Berntsen, S; Andersen, Lars Bo

    2010-01-01

    with the equations from the present study. None of the three could accurately predict the direct measured V.O2peak, and predictions differed in an unsystematic manner, including over- or underestimation and no differentiation between genders. CONCLUSION: Peak oxygen uptake could be estimated from Wmax and sex...

  12. Myocardial oxygen consumption at rest and during submaximal ...

    African Journals Online (AJOL)

    Overweight and obesity are major risk factors for cardiovascular diseases. The objective of this study was to determine the effect of increased adiposity on myocardial oxygen consumption at rest and during submaximal exercise in young adults. The study consisted of 85 young adults (18-22years) grouped into 3 based on ...

  13. Measurement of oxygen consumption rate of osteoblasts from ...

    African Journals Online (AJOL)

    The cells were evaluated through live/dead assay, hematoxylin-eosin (HE) and alkaline phosphatase (ALP) staining. Moreover, Von-Kossa staining and Alizarin Red S staining were carried out for mineralized nodule formation. Following this, the oxygen consumption rates of osteoblasts in the earlier mentioned different ...

  14. Restricting glycolysis impairs brown adipocyte glucose and oxygen consumption

    DEFF Research Database (Denmark)

    Winther, Sally; Isidor, Marie Sophie; Basse, Astrid Linde

    2018-01-01

    During thermogenic activation, brown adipocytes take up large amounts of glucose. In addition, cold stimulation leads to an upregulation of glycolytic enzymes. Here we have investigated the importance of glycolysis for brown adipocyte glucose consumption and thermogenesis. Using siRNA-mediated kn......During thermogenic activation, brown adipocytes take up large amounts of glucose. In addition, cold stimulation leads to an upregulation of glycolytic enzymes. Here we have investigated the importance of glycolysis for brown adipocyte glucose consumption and thermogenesis. Using si...... of glycolysis, i.e., hexokinase 2 (HK2) and pyruvate kinase M (PKM), respectively, decreased glucose uptake and ISO-stimulated oxygen consumption. HK2 knockdown had a more severe effect, which, in contrast to PKM knockdown, could not be rescued by supplementation with pyruvate. Hence, brown adipocytes rely...... on glucose consumption and glycolytic flux to achieve maximum thermogenic output, with glycolysis likely supporting thermogenesis not only by pyruvate formation but also by supplying intermediates for efferent metabolic pathways....

  15. Therapeutic effect of forearm low level light treatment on blood flow, oxygenation, and oxygen consumption

    Science.gov (United States)

    Wang, Pengbo; Sun, Jiajing; Meng, Lingkang; Li, Zebin; Li, Ting

    2018-02-01

    Low level light/laser therapy (LLLT) is considered as a novel, non-invasive, and potential therapy in a variety of psychological and physical conditions, due to its effective intricate photobiomodulation. The mechanism of LLLT is that when cells are stimulated by photons, mitochondria produce a large quantity of ATP, which accelerates biochemical responses in the cell. It is of great significance to gain a clear insight into the change or interplay of various physiological parameters. In this study, we used functional near-infrared spectroscopy (fNIRS) and venous-occlusion plethysmography to measure the LLLT-induced changes in blood flow, oxygenation, and oxygen consumption in human forearms in vivo. Six healthy human participants (4 males and 2 females) were administered with 810-nm light emitted by LED array in ten minutes and blood flow, oxygenation and oxygen consumption were detected in the entire experiment. We found that LLLT induced an increase of blood flow and oxygen consumption on the treated site. Meanwhile, LLLT took a good role in promoting oxygenation of regional tissue, which was indicated by a significant increase of oxygenated hemoglobin concentration (Δ[HbO2]), a nearly invariable deoxygenated hemoglobin concentration (Δ[Hb]) and a increase of differential hemoglobin concentration (Δ[HbD] = Δ[HbO2] - Δ[Hb]). These results not only demonstrate enormous potential of LLLT, but help to figure out mechanisms of photobiomodulation.

  16. Effects of motexafin gadolinium on tumor oxygenation and cellular oxygen consumption

    International Nuclear Information System (INIS)

    Donnelly, E.T.; Liu, Y.; Rockwell, S.; Magda, D.

    2003-01-01

    Full text: Recent work in our laboratory showed that motexafin gadolinium (MGd, Xcytrin), a drug currently in Phase III clinical trials as an adjuvant to radiation therapy, modulates the oxygen tensions in EMT6 tumors. The median pO 2 increased from the control value of 1.5±0.4 mmHg to 7.4 ± 3.8 mmHg six hours after treatment with 40 μmol/kg MGd and the percentage of severely hypoxic readings in the tumors ( 7 plateau phase EMT6 cells in 3 mL Dulbecco's Modified Eagle's Medium supplemented with 10% dialyzed fetal bovine serum, which contains no ascorbic acid. In the absence of ascorbic acid, 100 μM MGd did not alter the cellular oxygen consumption rate for EMT6 cells significantly. Marked inhibition of cellular oxygen consumption was observed when cells were incubated with 100 μM MGd in medium supplemented with equimolar ascorbic acid (a 31.5% decrease in consumption was observed after 6 hours of treatment). The 5% mannitol vehicle solution with equimolar ascorbic acid had no discernible effect on cellular oxygen consumption. Ascorbic acid may facilitate cellular uptake of MGd via the intermediate formation of a MGd-oxalate complex. These studies suggest that changes in cellular oxygen consumption could contribute to the changes in tumor oxygenation seen after administration of MGd. These experiments were supported by Pharmacyclics and training grant T32CA09085 from the NIH (E.T.D.). We thank Dr. Raymond Russell for allowing us to use his oxygen electrode apparatus

  17. Do individuals with intellectual disability have a lower peak heart rate and maximal oxygen uptake?

    Science.gov (United States)

    Hilgenkamp, Thessa Irena Maria; Baynard, Tracy

    2017-12-12

    Individuals with intellectual disability (ID) have very low physical activity and low peak oxygen uptake (VO 2peak ), potentially explained by physiologically lower peak heart rates (HR peak ). The present authors performed a retrospective analysis of a large data set of individuals with intellectual disability (n = 100), with Down syndrome (DS) (n = 48) and without intellectual disability (n = 224) using multiple linear regression analyses, to determine if individuals with intellectual disability exhibit lower HR peak and VO 2peak than individuals without intellectual disability, controlling for age, sex and body mass index (BMI). Individuals with intellectual disability on average have significantly lower HR peak and VO 2peak than individuals without intellectual disability, even when controlling VO 2peak for the lower HR peak . This study suggests potential physiological differences in individuals with intellectual disability and warrants further investigation to determine their relevance to physical activity promotion and exercise testing in individuals with intellectual disability. © 2017 John Wiley & Sons Ltd.

  18. Oxygen consumption by hydrazine in long sample lines

    International Nuclear Information System (INIS)

    Chi, Lisheng; Turner, Carl-W.

    2012-09-01

    In nuclear power plants secondary side system dissolved oxygen concentration is a strictly controlled chemistry parameter intended to minimize corrosion and fouling of steam cycle components. Low dissolved oxygen concentration is maintained by a combination of mechanical de-aeration and chemical reaction. The dissolved oxygen concentration in feedwater is monitored by sampling systems to ensure it remains within station specification during operation. The sample lines in a nuclear power plant's sampling system can be from 5 to nearly 200 meters in length, resulting in sample residence times between the take-off point to the analyzer from a few seconds to several minutes, depending on the flow rate and the length of the sample line. For many chemical parameters the residence time is of no concern. For measurements of dissolved oxygen and hydrazine in the secondary coolant, however, for residence times longer than one minute, it is uncertain whether the sample is representative of conditions in the secondary coolant, especially for samples taken from locations where the temperature is well over 100 deg. C. To address this concern, a series of tests were conducted under both warm-up and power operation conditions, respectively, to investigate the effect of temperature, residence time, sample line length, surface area, hydrazine-to-oxygen ratio, and the concentrations of dissolved oxygen and hydrazine on the consumption of oxygen by hydrazine. The test results revealed that dissolved oxygen measurements in CANDU plants are underestimated to various degrees, depending on the sampling system operating conditions. Two distinct types of behaviours are observed for the oxygen removal rate: 1) the percentage removal of dissolved oxygen is invariant with time during the tests, and increases with increasing residence time in the test section, when the reaction between hydrazine and oxygen is better described by a homogenous reaction mechanism, and 2) the percentage oxygen

  19. Relationship of bronchodilator response with oxygen pulse and ventilatory threshold in children with asthma: the effect of body composition and progressive aerobic activity in an environment with low humidity

    Directory of Open Access Journals (Sweden)

    Samera Puyan majd

    2015-11-01

    Full Text Available Background: Asthma is a leading cause of chronic illness in children, impacting heavily on their daily complications. The purpose of the present study was to relationship bronchodilator response (BDR with oxygen pulse (OP and ventilatory threshold (VT in asthma children with various body compositions during progressive aerobic activities. Material and Methods: 25 obese children (BMI>25 and %fat>30with asthma(10 subjects, and healthy children (15 subjects  and 25 lean children(BMI<20 and %fat<20 with asthma(13 subjects, and healthy children (7 subjects performed an exercise protocol in a constant temperature environment 2 ± 22 ° C and humidity (5 ± 35%. During exercise, the steady-state levels of cardio-respiratory parameters were measured using gas analyzer (K4B2. Results: The results showed that after a progressive aerobic activity, values peak oxygen consumption(vo2peak ​​, bronchodilator(BDR, oxygen pulse(OP and ventilatory threshold(VT  in lean and obese asthmatic children were lower than in healthy lean and obese children. In addition, lean children with asthma had lower VT and higher VO2peak , OP and BDR values​​, as compared obese asthmatic children. Between BDR and VT in lean and obese asthmatic children an inverse relationship between BDR and OP and a direct link to asthma in obese children and obese asthmatic children, there was a negative relationship non-significant. Conclusion: Compared with lean children, asthma, obesity as an additional load will affect lung function and increase the pressure on childhood asthma. Therefore, we can accept that obesity may limit performance of exercise in childhood asthma.

  20. Oxygen consumption in EPDM irradiated under different oxygen pressures and at different LET

    International Nuclear Information System (INIS)

    Dely, N.; Ngono-Ravache, Y.; Ramillon, J.-M.; Balanzat, E.

    2005-01-01

    We conceived a novel set-up for measuring the radiochemical yields of oxygen consumption in polymers. The measurement is based on a sampling of the gas mixture with a mass spectrometer, before and after irradiation. We irradiated an ethylene, propylene and 1,4-hexadiene terpolymer (EPDM) with 1 MeV electron and 10.75 MeV/A carbon beams. Samples were irradiated under oxygen within a wide range of pressure (5-200 mbar). The yields under C irradiation are four times smaller than the yields under electron irradiation. This shows that radiooxidation is very sensitive to the linear energy transfer of the projectiles and hence to the heterogeneity of the energy deposition. The oxygen consumption yields do not vary significantly in the range of pressure investigated; even at 5 mbar, the kinetics is still governed by the bimolecular recombination of peroxy radicals

  1. Simultaneous sampling of tissue oxygenation and oxygen consumption in skeletal muscle.

    Science.gov (United States)

    Nugent, William H; Song, Bjorn K; Pittman, Roland N; Golub, Aleksander S

    2016-05-01

    Under physiologic conditions, microvascular oxygen delivery appears to be well matched to oxygen consumption in respiring tissues. We present a technique to measure interstitial oxygen tension (PISFO2) and oxygen consumption (VO2) under steady-state conditions, as well as during the transitions from rest to activity and back. Phosphorescence Quenching Microscopy (PQM) was employed with pneumatic compression cycling to achieve 1 to 10 Hz sampling rates of interstitial PO2 and simultaneous recurrent sampling of VO2 (3/min) in the exteriorized rat spinotrapezius muscle. The compression pressure was optimized to 120-130 mmHg without adverse effect on the tissue preparation. A cycle of 5s compression followed by 15s recovery yielded a resting VO2 of 0.98 ± 0.03 ml O2/100 cm(3)min while preserving microvascular oxygen delivery. The measurement system was then used to assess VO2 dependence on PISFO2 at rest and further tested under conditions of isometric muscle contraction to demonstrate a robust ability to monitor the on-kinetics of tissue respiration and the compensatory changes in PISFO2 during contraction and recovery. The temporal and spatial resolution of this approach is well suited to studies seeking to characterize microvascular oxygen supply and demand in thin tissues. Copyright © 2015 Elsevier Inc. All rights reserved.

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

    Science.gov (United States)

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

    2017-08-01

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

  3. Benthic oxygen consumption on continental shelves off eastern Canada

    Science.gov (United States)

    Grant, Jonathan; Emerson, Craig W.; Hargrave, Barry T.; Shortle, Jeannette L.

    1991-08-01

    The consumption of phytoplankton production by the benthos is an important component of organic carbon budgets for continental shelves. Sediment texture is a major factor regulating benthic processes because fine sediment areas are sites of enhanced deposition from the water column, resulting in increased organic content, bacterial biomass and community metabolism. Although continental shelves at mid- to high latitudes consist primarily of coarse relict sediments ( PIPER, Continental Shelf Research, 11, 1013-1035), shelf regions of boreal and subarctic eastern Canada contain large areas of silt and clay sediments ( FADER, Continental Shelf Research, 11, 1123-1153). We collated estimates of benthic oxygen consumption in coarse (<20% silt-clay, <0.5% organic matter) and fine sediments (20% silt-clay, 0.5% organic matter) for northwest Atlantic continental shelves including new data for Georges Bank, the Scotian Shelf, the Grand Banks of Newfoundland and Labrador Shelf. Estimates were applied to the areal distribution of sediment type on these shelves to obtain a general relationship between sediment texture and benthic carbon consumption. Mean benthic oxygen demand was 2.7 times greater in fine sediment than in coarse sediment, when normalized to mean annual temperature. In terms of carbon equivalents, shelf regions with minimal fine sediment (Georges Bank, the Grand Banks of Newfoundland-northeast Newfoundland) consumed only 5-8% of annual primary production. Benthos of the Gulf of Maine (100% fine sediment) and the Scotian Shelf (35% fine sediment) utilized 16-19% of primary production. Although 32% of the Labrador Shelf area contained fine sediments, benthic consumption of pelagic production (8%) was apparently limited by low mean annual temperature (2°C). These results indicate that incorporation of sediment-specific oxygen uptake into shelf carbon budgets may increase estimates of benthic consumption by 50%. Furthermore, respiration and production by large

  4. Asymmetry of quadriceps muscle oxygenation during elite short-track speed skating.

    Science.gov (United States)

    Hesford, Catherine Mary; Laing, Stewart J; Cardinale, Marco; Cooper, Chris E

    2012-03-01

    It has been suggested that, because of the low sitting position in short-track speed skating, muscle blood flow is restricted, leading to decreases in tissue oxygenation. Therefore, wearable wireless-enabled near-infrared spectroscopy (NIRS) technology was used to monitor changes in quadriceps muscle blood volume and oxygenation during a 500-m race simulation in short-track speed skaters. Six elite skaters, all of Olympic standard (age = 23 ± 1.8 yr, height = 1.8 ± 0.1 m, mass = 80.1 ± 5.7 kg, midthigh skinfold thickness = 7 ± 2 mm), were studied. Subjects completed a 500-m race simulation time trial (TT). Whole-body oxygen consumption was simultaneously measured with muscle oxygenation in right and left vastus lateralis as measured by NIRS. Mean time for race completion was 44.8 ± 0.4 s. VO2 peaked 20 s into the race. In contrast, muscle tissue oxygen saturation (TSI%) decreased and plateaued after 8 s. Linear regression analysis showed that right leg TSI% remained constant throughout the rest of the TT (slope value = 0.01), whereas left leg TSI% increased steadily (slope value = 0.16), leading to a significant asymmetry (P skating has implications for training and performance.

  5. Assessing peak aerobic capacity in Dutch law enforcement officers

    NARCIS (Netherlands)

    Wittink, Harriet; Takken, Tim; de Groot, Janke; Reneman, Michiel; Peters, Roelof; Vanhees, Luc

    2015-01-01

    Objectives: To cross-validate the existing peak rate of oxygen consumption (VO2peak) prediction equations in Dutch law enforcement officers and to determine whether these prediction equations can be used to predict VO2peak for groups and in a single individual. A further objective was to report

  6. Assessing peak aerobic capacity in Dutch law enforcement officers.

    NARCIS (Netherlands)

    Wittink, H.; Takken, T.; Groot, J.F. de; Reneman, M.; Peters, R.; Vanhees, L.

    2015-01-01

    Objectives: To cross-validate the existing peak rate of oxygen consumption (VO2peak) prediction equations in Dutch law enforcement officers and to determine whether these prediction equations can be used to predict VO2peak for groups and in a single individual. A further objective was to report

  7. Oxygen consumption during exercise in a heated pool.

    Science.gov (United States)

    Kirby, R L; Sacamano, J T; Balch, D E; Kriellaars, D J

    1984-01-01

    The heated hydrotherapy pool is a common exercise site for patients with painful musculoskeletal conditions. Oxygen consumption of swimming is 87 to 89% of maximum in postmyocardial infarction patients according to one recent investigation. We studied 13 able-bodied subjects to test the hypothesis that enough energy could be expended during various forms of hydrotherapy to produce both an aerobic training effect and a risk to patients with coronary artery disease. Oxygen consumption (VO2) was measured in six settings: resting supine; resting seated shoulder deep in the pool (36C); walking at comfortable speed in chest-deep water; running at the fastest speed possible in chest-deep water; using hand paddles; and running in place at shoulder depth. The mean VO2 expressed in ml/kg/min (and metabolic equivalents) were 4.91 (1.00), 4.93 (1.02), 9.34 (2.01), 27.79 (6.23), 18.25 (4.30) and 29.11 (7.09) respectively, suggesting that the more vigorous exercises stress aerobic capacity heavily but not excessively.

  8. Oxygen consumption and blood flow coupling in human motor cortex during intense finger tapping

    DEFF Research Database (Denmark)

    Seyedi Vafaee, Manouchehr; Vang, Kim; Bergersen, Linda H

    2012-01-01

    Rates of cerebral blood flow (CBF) and glucose consumption (CMR(glc)) rise in cerebral cortex during continuous stimulation, while the oxygen-glucose index (OGI) declines as an index of mismatched coupling of oxygen consumption (cerebral metabolic rate of oxygen-CMRO(2)) to CBF and CMR(glc). To t...

  9. Effect of meal and propranolol on whole body and splanchnic oxygen consumption in patients with cirrhosis

    DEFF Research Database (Denmark)

    Krag, Aleksander; Simonsen, Lene; Henriksen, Jens H

    2006-01-01

    Our aim was to measure whole body energy expenditure after a mixed liquid meal, with and without simultaneous propranolol infusion, in patients with cirrhosis. We also wanted to investigate the effect of propranolol on substrate fluxes and oxygen uptake in the tissues drained by the hepatic vein ...... as splanchnic oxygen uptake. The splanchnic reduction in oxygen consumption can explain almost the entire reduction in whole body oxygen consumption....

  10. COMPARISON OF OXYGEN UPTAKE KINETICS AND OXYGEN DEFICIT IN SEVERELY OVERWEIGHT AND NORMAL WEIGHT ADOLESCENT FEMALES

    Directory of Open Access Journals (Sweden)

    Mark Loftin

    2005-12-01

    Full Text Available The purpose of this study was to determine if differences in oxygen uptake kinetics and oxygen deficit existed between normal weight and severely overweight adolescent girls. Subjects included 10 normal weight and 8 severely overweight girls. The participants performed a leg cycling VO2 peak test and a constant load leg cycling test at 80% of the ventilatory threshold (T-vent. In the constant workload test O2 kinetics as indicated by Phase I (VO2 L at 20 sec and Phase II time constants (t were determined. Also, the O2 deficit (VO2 L was measured. As expected significant differences were noted in body composition and VO2 peak relative to mass with normal weight body mass averaging 55.3 ± 7.0 kg, severely overweight 90.5 ± 18.0 kg, % fat normal weight 27.3 ± 3.9%, severely overweight 49.7 ± 4.9% and VO2 peak (ml·kg-1·min-1 normal weight 32.0 ± 2.7 and severely overweight 22.0 ± 5.3. VO2 peak (l·min-1 and T-vent (%VO2 max were similar between groups. Results revealed similar O2 kinetic responses between groups; phase I kinetics normal weight 0.72 ± 0.15 L; severely overweight 0.75 ± 0.13L, phase II (t normal weight 41.5 ± 21.3 sec; severely overweight 33.9 ± 22.7 sec. However, the O2 deficit was significantly higher in the severely overweight (0.75 ± 0.15L when compared to the normal weight group (0.34 ± 0.13L. Correlations ranged from r = -0.15 to 0.51 between VO2 peak (L·min-1 or fat weight and phase I, t and O2 deficit. These data generally support previous research concerning the independence of O2 uptake response and body size

  11. Effect of music-movement synchrony on exercise oxygen consumption.

    Science.gov (United States)

    Bacon, C J; Myers, T R; Karageorghis, C I

    2012-08-01

    Past research indicates that endurance is improved when exercise movements are synchronised with a musical beat, however it is unclear whether such benefits are associated with reduced metabolic cost. We compared oxygen consumption (.VO2) and related physiological effects of exercise conducted synchronously and asynchronously with music. Three music tracks, each recorded at three different tempi (123, 130, and 137 beats.min-1), accompanied cycle ergometry at 65 pedal revolutions.min-1. Thus three randomly-assigned experimental conditions were administered: slow tempo asynchronous, synchronous, and fast tempo asynchronous. Exercise response of .VO2, HR, and ratings of perceived exertion (RPE), to each condition was monitored in 10 untrained male participants aged 21.7±0.8 years (mean±SD) who cycled for 12 min at 70% maximal heart rate (HR). Mean .VO2 differed among conditions (P=0.008), being lower in the synchronous (1.80±0.22 L.min-1) compared to the slow tempo asynchronous condition (1.94±0.21 L.min-1; Pmusic than when musical tempo is slightly slower than the rate of cyclical movement.

  12. (-)-Epicatechin administration and exercising skeletal muscle vascular control and microvascular oxygenation in healthy rats.

    Science.gov (United States)

    Copp, Steven W; Inagaki, Tadakatsu; White, Michael J; Hirai, Daniel M; Ferguson, Scott K; Holdsworth, Clark T; Sims, Gabrielle E; Poole, David C; Musch, Timothy I

    2013-01-15

    Consumption of the dietary flavanol (-)-epicatechin (EPI) is associated with enhanced endothelial function and augmented skeletal muscle capillarity and mitochondrial volume density. The potential for EPI to improve peripheral vascular function and muscle oxygenation during exercise is unknown. We tested the hypothesis that EPI administration in healthy rats would improve treadmill exercise performance secondary to elevated skeletal muscle blood flow and vascular conductance [VC, blood flow/mean arterial pressure (MAP)] and improved skeletal muscle microvascular oxygenation. Rats received water (control, n = 12) or 4 mg/kg EPI (n = 12) via oral gavage daily for 24 days. Exercise endurance capacity and peak O(2) uptake (Vo(2) peak) were measured via treadmill runs to exhaustion. MAP (arterial catheter) and blood flow (radiolabeled microspheres) were measured and VC was calculated during submaximal treadmill exercise (25 m/min, 5% grade). Spinotrapezius muscle microvascular O(2) pressure (Po(2mv)) was measured (phosphorescence quenching) during electrically induced twitch (1 Hz) contractions. In conscious rats, EPI administration resulted in lower (↓~5%) resting (P = 0.03) and exercising (P = 0.04) MAP. There were no differences in exercise endurance capacity, Vo(2) peak, total exercising hindlimb blood flow (control, 154 ± 13; and EPI, 159 ± 8 ml·min(-1)·100 g(-1), P = 0.68), or VC (control, 1.13 ± 0.10; and EPI, 1.24 ± 0.08 ml·min(-1)·100 g(-1)·mmHg(-1), P = 0.21) between groups. Following anesthesia, EPI resulted in lower MAP (↓~16%) but did not impact resting Po(2mv) or any kinetics parameters (P > 0.05 for all) during muscle contractions compared with control. EPI administration (4 mg·kg(-1)·day(-1)) improved modestly cardiovascular function (i.e., ↓MAP) with no impact on exercise performance, total exercising skeletal muscle blood flow and VC, or contracting muscle microvascular oxygenation in healthy rats.

  13. The effect of temperature and salinity on oxygen consumption in the ...

    African Journals Online (AJOL)

    The aquatic oxygen consumption of the estuarine brachyuran crab, Cyclograpsus punctatus, was investigated after a 24-hour acclimation period at different temperature (12.5, 20, 30°C) and salinity (9, 17.5, 35, and 44‰) combinations . Salinity had no significant effect on oxygen consumption at 12.5 and 20°C in both large ...

  14. Determination of in vitro oxygen consumption rates for tumor cells

    International Nuclear Information System (INIS)

    Cardenas-Navia, L.I.; Moeller, B.J.; Kirkpatrick, J.P.; Laursen, T.A.; Dewhirst, M.W.

    2003-01-01

    To determine pO 2 at the surface of a monolayer of confluent HCT 116 cells, and to then determine consumption rate in vitro by examining the pO 2 profile in media above the cells. Materials and Methods: A recessed-tip polarographic oxygen microelectrode (diameter ∼10μm) was used to measure pO 2 profiles of media above a confluent monolayer of HCT 116 human colon adenocarcinoma cells in a T25 flask exposed to a 95% air, 5% CO 2 mixture. A two-dimensional finite element analysis of the diffusion equation was used to fit the data, thereby extracting a steady-state O 2 consumption rate. The diffusion equation was solved for zeroth and first-order expressions. No-flux boundary conditions were imposed on its bottom and side boundaries and experimental data was used for boundary conditions at the gas-media boundary. All flasks show an O 2 gradient in the media, with a mean (SE) media layer of 1677 (147) μm and a mean pO 2 at the cell layer/media interface of 44 (8) mm Hg (n=9). pO 2 gradient over the entire media layer is 630 (90) mm Hg/cm, equivalent to a consumption rate of 6.3 x 10 -4 (9.0 x 10 -5 ) mm Hg/s. The mean values for the zeroth and first order rate constants are 8.1 x 10 -9 (1.3 x 10 -9 ) g mol O 2 /cm 3 s and 1.0 x 10 3 (0.46 x 10 3 ) /s, respectively. Control experiments in flasks containing no cells show slight gradients in pO 2 of 38 (12) mm Hg/cm, resulting from some O 2 diffusion through the flask into the surrounding water bath. An addition of 10 -3 M NaCN to the media results in a dramatic increase in pO 2 at the cell layer, consistent with a shut-down in respiration. Under normal cell culture conditions there is an O 2 gradient present in the media of cull culture systems, resulting in physiologic O 2 concentrations at the cell layer, despite the non-physiologic O 2 concentration of the gas mixture to which the cell culture system is exposed. This significant (p -6 ) O 2 gradient in the media of cell culture systems is a result of cell O 2

  15. Microgradients of microbial oxygen consumption in a barley rhizosphere model system

    DEFF Research Database (Denmark)

    Højberg, Ole; Sorensen, J.

    1993-01-01

    A microelectrode technique was used to map the radial distribution of oxygen concentrations and oxygen consumption rates around single roots of 7- day-old barley seedlings. The seedlings were grown in gel-stabilized medium containing a nutrient solution, a soil extract, and an inert polymer. Oxygen...... consumption by microbial respiration in the rhizosphere (30 mm from the root) was determined by using Fick's laws of diffusion and an analytical approach with curve fitting to measured microprofiles of oxygen concentration. A marked increase of microbial respiration...... was observed in the inner 0- to 3-mm-thick, concentric zone around the root (rhizosphere). The volume-specific oxygen consumption rate (specific activity) was thus 30 to 60 times higher in the innermost 0 to 0.01 mm (rhizoplane) than in the bulk medium. The oxygen consumption rate in the root tissue...

  16. Maximal Oxygen Consumption is Reduced in Aquaporin-1 Knockout Mice

    Directory of Open Access Journals (Sweden)

    Samer Al-Samir

    2016-08-01

    Full Text Available We have measured maximal oxygen consumption (V’O2,max of mice lacking one or two of the established mouse red-cell CO2 channels AQP1, AQP9 and Rhag. We intended to study whether these proteins, by acting as channels for O2, determine O2 exchange in the lung and in the periphery. We found that V’O2,max as determined by the Helox technique is reduced by ~ 16%, when AQP1 is knocked out, but not when AQP9 or Rhag are lacking. This figure holds for animals respiring normoxic as well as hypoxic gas mixtures. To see whether the reduction of V’O2,max is due to impaired O2 uptake in the lung, we measured carotid arterial O2 saturation (SO2 by pulse oximetry. Neither under normoxic (inspiratory O2 21% nor under hypoxic conditions (11% O2 is there a difference in SO2 between AQP1null and WT mice, suggesting that AQP1 is not critical for O2 uptake in the lung. The fact that the % reduction of V’O2,max is identical in normoxia and hypoxia indicates moreover that the limitation of V’O2,max is not due to an O2 diffusion problem, neither in the lung nor in the periphery. Instead, it appears likely that AQP1null animals exhibit a reduced V’O2,max due to the reduced wall thickness and muscle mass of the left ventricles of their hearts, as reported previously. We conclude that very likely the properties of the hearts of AQP1 knockout mice cause a reduced maximal cardiac output and thus cause a reduced V’O2,max, which constitutes a new phenotype of these mice.

  17. Excess posthypoxic oxygen consumption in rainbow trout (Oncorhynchus mykiss): recovery in normoxia and hypoxia

    DEFF Research Database (Denmark)

    Svendsen, Jon Christian; Steffensen, John Fleng; Aarestrup, Kim

    2012-01-01

    at which the standard metabolic rate becomes dependent upon the ambient oxygen content. Using rainbow trout (Oncorhynchus mykiss (Walbaum, 1792), this study quantified the excess posthypoxic oxygen consumption (EPHOC) occurring after exposure to oxygen availability below S(crit). Tests showed that S...

  18. Physiological modelling of oxygen consumption in birds during flight

    Science.gov (United States)

    Bishop; Butler

    1995-01-01

    This study combines data on changes in cardiovascular variables with body mass (Mb) and with exercise intensity to model the oxygen supply available to birds during flight. Its main purpose is to provide a framework for identifying the factors involved in limiting aerobic power input to birds during flight and to suggest which cardiovascular variables are the most likely to have been influenced by natural selection when considering both allometric and adaptive variation. It is argued that natural selection has acted on heart rate (fh) and cardiac stroke volume (Vs), so that the difference in the arteriovenous oxygen content (CaO2-Cv¯O2) in birds, both at rest and during flight, is independent of Mb. Therefore, the Mb exponent for oxygen consumption (V(dot)O2) during flight can be estimated from measurements of heart rate and stroke volume. Stroke volume is likely to be directly proportional to heart mass (Mh) and, using empirical data, values for the Mb coefficients and exponents of various cardiovascular variables are estimated. It is concluded that, as found for mammals, fh is the main adaptive variable when considering allometric variation, although Mh also shows a slight scaling effect. Relative Mh is likely to be the most important when considering adaptive specialisations. The Fick equation may be represented as: (V(dot)O2)Mbz = (fh)Mbw x (Vs)Mbx x (CaO2 - Cv¯O2)Mby , where w, x, y, z are the body mass exponents for each variable and the terms in parentheses represent the Mb coefficients. Utilising this formula and data from the literature, the scaling of minimum V(dot)O2 during flight for bird species with a 'high aerobic capacity' (excluding hummingbirds) is calculated to be: 166Mb0.77±0.09 = 574Mb-0.19±0.02 x 3.48Mb0.96±0.02 x 0.083Mb0.00±0.05 , and for hummingbirds (considered separately owing to their unique wing kinematics) it is: 314Mb0.90±0.22 = 617Mb-0.10±0.06 x 6.13Mb1.00±0.11 x 0.083Mb0.00±0.05 . These results are largely dependent on the

  19. Relations of morphological characteristics and maximal oxygen consumption of fourth grade pupils based on gender

    Directory of Open Access Journals (Sweden)

    Jakovljević Vladimir

    2014-01-01

    Full Text Available On a sample of 71 respondents, 37 boys and 34 girls, age of fourth grade elementary school, accordingly 9 years +/- 6 months, it is assessed correlation and prediction of maximal oxygen consumption based measures of morphological range. Maximum oxygen consumption was measured by indirect method, using a field test of maximal multiple load of feedback running at 20 meters. Range of morphology was analyzed based on 5 measures of longitudinal dimensionality, 4 measures of volume and body mass and 3 measures of transversal dimensionality. Results of correlation analysis showed that in both sexes there was no statistically significant correlation between results of maximal oxygen consumption and measures of longitudinal dimensionality, while regression analysis confirmed that there was no statistically significant prediction of maximum oxygen consumption based on measures of longitudinal dimensionality. While the correlation analysis deduced that part of volume measures and body mass and transversal dimensionality have statistically significant correlation only with female respondents with results of maximal oxygen consumption. Regression analysis showed statistically significant prediction of maximal oxygen consumption based on part of volume measures and body mass and transversal dimensionality. It is determined that female respondents with larger volumes of the thigh and lower leg, accordingly with smaller diameters of knee joint and ankle joint most likely will achieve better results in applied test, and therefore higher maximal oxygen consumption.

  20. Heart rate during basketball game play and volleyball drills accurately predicts oxygen uptake and energy expenditure.

    Science.gov (United States)

    Scribbans, T D; Berg, K; Narazaki, K; Janssen, I; Gurd, B J

    2015-09-01

    There is currently little information regarding the ability of metabolic prediction equations to accurately predict oxygen uptake and exercise intensity from heart rate (HR) during intermittent sport. The purpose of the present study was to develop and, cross-validate equations appropriate for accurately predicting oxygen cost (VO2) and energy expenditure from HR during intermittent sport participation. Eleven healthy adult males (19.9±1.1yrs) were recruited to establish the relationship between %VO2peak and %HRmax during low-intensity steady state endurance (END), moderate-intensity interval (MOD) and high intensity-interval exercise (HI), as performed on a cycle ergometer. Three equations (END, MOD, and HI) for predicting %VO2peak based on %HRmax were developed. HR and VO2 were directly measured during basketball games (6 male, 20.8±1.0 yrs; 6 female, 20.0±1.3yrs) and volleyball drills (12 female; 20.8±1.0yrs). Comparisons were made between measured and predicted VO2 and energy expenditure using the 3 equations developed and 2 previously published equations. The END and MOD equations accurately predicted VO2 and energy expenditure, while the HI equation underestimated, and the previously published equations systematically overestimated VO2 and energy expenditure. Intermittent sport VO2 and energy expenditure can be accurately predicted from heart rate data using either the END (%VO2peak=%HRmax x 1.008-17.17) or MOD (%VO2peak=%HRmax x 1.2-32) equations. These 2 simple equations provide an accessible and cost-effective method for accurate estimation of exercise intensity and energy expenditure during intermittent sport.

  1. Preliminary Study on the Oxygen Consumption Dynamics During Brain Hypothermia Resuscitation

    National Research Council Canada - National Science Library

    Ji, Yan

    2001-01-01

    .... Two cooling approaches (the surface cooling and volumetric cooling are applied to analyze the effect of hypothermia on the transient temperature and the oxygen consumption rate in different regions of brain...

  2. Comparative oxygen consumption rates of subitaneous and delayed hatching eggs of the calanoid copepod Acartia tonsa (Dana)

    DEFF Research Database (Denmark)

    Hansen, Benni Winding; Drillet, Guillaume

    2013-01-01

    nanorespirometry to monitor initial oxygen consumption rate of individual eggs of the ubiquitous neritic calanoid copepod Acartia tonsa to distinguish between subitaneous and DHE. We hypothesized that subitaneous eggs exhibit higher initial oxygen consumption rates than DHE, and that initial egg oxygen consumption...... rate is correlated to the time for the individual egg to hatch. Subitaneous eggs exhibited higher initial oxygen consumption rates than DHE and there were no pattern in initial oxygen consumption rates vs. time to hatch or die from the eggs. Variability in initial oxygen consumption rates within...... batches of both subitaneous and DHE, as well as between these egg types, is prevalent. There was a continuum from sluggish- to fast metabolising eggs considering initial oxygen consumption rates most likely reflecting phenotypic variation within cohorts. No matter the individual initial egg oxygen...

  3. Oxygen consumption and responses of the freshwater snail Bulinus ...

    African Journals Online (AJOL)

    behaviour to oxygen differences in the water is of special interest. Knowledge of this ... fold, the prosobranch, to enhance the gaseous exchange between the animal ..... meins that little stress on the respiration ability was encountered towards ...

  4. Measurement of oxygen consumption rate of osteoblasts from ...

    African Journals Online (AJOL)

    Jane

    2011-05-10

    May 10, 2011 ... E-mail: kedongsong@dlut.edu.cn. Tel: +86 411 ... the experiments, including inverted phase contrast microscope. (IX70-Olympus ... The pictures showed that the osteoblasts still had very high cellular viability. consumption of ...

  5. Oxygen consumption rates by different oenological tannins in a model wine solution.

    Science.gov (United States)

    Pascual, Olga; Vignault, Adeline; Gombau, Jordi; Navarro, Maria; Gómez-Alonso, Sergio; García-Romero, Esteban; Canals, Joan Miquel; Hermosín-Gutíerrez, Isidro; Teissedre, Pierre-Louis; Zamora, Fernando

    2017-11-01

    The kinetics of oxygen consumption by different oenological tannins were measured in a model wine solution using the non-invasive method based on luminiscence. The results indicate that the oxygen consumption rate follows second-order kinetics depending on tannin and oxygen concentrations. They also confirm that the oxygen consumption rate is influenced by temperature in accordance with Arrhenius law. The indications are that ellagitannins are the fastest oxygen consumers of the different oenological tannins, followed in decreasing order by quebracho tannins, skin tannins, seed tannins and finally gallotannins. This methodology can therefore be proposed as an index for determining the effectiveness of different commercial tannins in protecting wines against oxidation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Biotite dissolution and oxygen consumption in aqueous media at 100 degrees C

    International Nuclear Information System (INIS)

    Taylor, P.; Owen, D.G.

    1997-04-01

    The ability of biotite to consume dissolved oxygen, and hence restore reducing conditions in a nuclear fuel waste vault after closure, has been assessed experimentally. Oxygen consumption has been measured directly, and also deduced from experimental biotite dissolution rates. Results from the dissolution experiments on granitic biotite from the Lac du Bonnet region, Manitoba indicate that the biotite component of granite backfill should consume entrained oxygen in about 50 years at 100 degrees C. Direct measurements of oxygen consumption by commercial biotite specimens originating from Bancroft, Ontario were reasonably consistent with this finding. Magnetite is significantly more effective than biotite at oxygen consumption, perhaps two orders of magnitude faster at 100 degrees C. (author)

  7. Effects of extracellular zinc ion on the rate of oxygen consumption of ...

    African Journals Online (AJOL)

    The inhibitory effect of extracellular zinc ion on the rate of oxygen consumption of rat brain mitochondria pre-incubated in 1.0 mM Ca2+EDTA were determined. There was a significant increase [P<0.01] in the rate of oxygen consumption in the rat brain mitochondria pre-incubated in 1.0 mM. Ca2+EDTA in a succinate ...

  8. Excess post-hypoxic oxygen consumption is independent from lactate accumulation in two cyprinid fishes

    DEFF Research Database (Denmark)

    Genz, J.; Jyde, M.B.; Svendsen, Jon Christian

    2013-01-01

    the increase in oxygen consumption in fish required following strenuous exercise or low environmental oxygen availability has been frequently considered, the primary contributing mechanism remains unknown. This study utilized the close relationship but strongly divergent physiology between C. carpio and C...

  9. Oxygen consumption through metabolism and photodynamic reactions in cells cultured on microbeads

    International Nuclear Information System (INIS)

    Schunck, T.; Poulet, P.

    2000-01-01

    Oxygen consumption by cultured cells, through metabolism and photosensitization reactions, has been calculated theoretically. From this result, we have derived the partial oxygen pressure P O 2 in the perfusion medium flowing across sensitized cultured cells during photodynamic experiments. The P O 2 variations in the perfusate during light irradiation are related to the rate of oxygen consumption through photoreactions, and to the number of cells killed per mole of oxygen consumed through metabolic processes. After irradiation, the reduced metabolic oxygen consumption yields information on the cell death rate, and on the photodynamic cell killing efficiency. The aim of this paper is to present an experimental set-up and the corresponding theoretical model that allows us to control the photodynamic efficiency for a given cell-sensitizer pair, under well defined and controlled conditions of irradiation and oxygen supply. To demonstrate the usefulness of the methodology described, CHO cells cultured on microbeads were sensitized with pheophorbide a and irradiated with different light fluence rates. The results obtained, i.e. oxygen consumption of about 0.1 μMs -1 m -3 under a light fluence rate of 1 W m -2 , 10 5 cells killed per mole of oxygen consumed and a decay rate of about 1 h -1 of living cells after irradiation, are in good agreement with the theoretical predictions and with previously published data. (author)

  10. Effect of selective blockade of oxygen consumption, glucose transport, and Ca2+ influx on thyroxine action in human mononuclear cells

    DEFF Research Database (Denmark)

    Kvetny, J; Matzen, L E

    1990-01-01

    The effect of selective blockade of cellular glucose transporters, Ca2+ influx, and mitochondrial oxygen consumption on thyroxine (T4)-stimulated oxygen consumption and glucose uptake was examined in human mononuclear blood cells. Blockade of glucose transporters by cytochalasin B (1 x 10(-5) mol....../L) and of Ca2+ influx by alprenolol (1 x 10(-5) mol/L) and verapamil (4 x 10(-4) mol/L) inhibited T4-activated glucose uptaken and reduced T4-stimulated oxygen consumption by 20%. Uncoupling of mitochondrial oxygen consumption by azide (1 x 10(-3) mol/L) inhibited T4-stimulated oxygen consumption, but had...... no effect on glucose uptake. We conclude that T4-stimulated glucose uptake in human mononuclear blood cells is dependent on intact glucose transporters and Ca2+ influx, but not on mitochondrial oxygen consumption. However, oxygen consumption is, in part, dependent on intact glucose uptake....

  11. Influence of Substrate Composition on vitro Oxygen Consumption of ...

    African Journals Online (AJOL)

    1974-09-11

    Sep 11, 1974 ... and it activates the angiotensin sys- tem by converting angiotensin I to angiotensin n.l3 It also participates in the de 110\\10 synthesis of fatty acids," pro- teins" and of phospholipids (surfactant)." The oxygen consumed by the lung is used not only for its own basal metabolic needs but for additional metabolic.

  12. Uptake rate of cationic mitochondrial inhibitor MKT-077 determines cellular oxygen consumption change in carcinoma cells.

    Directory of Open Access Journals (Sweden)

    John L Chunta

    Full Text Available OBJECTIVE: Since tumor radiation response is oxygen-dependent, radiosensitivity can be enhanced by increasing tumor oxygenation. Theoretically, inhibiting cellular oxygen consumption is the most efficient way to increase oxygen levels. The cationic, rhodacyanine dye-analog MKT-077 inhibits mitochondrial respiration and could be an effective metabolic inhibitor. However, the relationship between cellular MKT-077 uptake and metabolic inhibition is unknown. We hypothesized that rat and human mammary carcinoma cells would take up MKT-077, causing a decrease in oxygen metabolism related to drug uptake. METHODS: R3230Ac rat breast adenocarcinoma cells were exposed to MKT-077. Cellular MKT-077 concentration was quantified using spectroscopy, and oxygen consumption was measured using polarographic electrodes. MKT-077 uptake kinetics were modeled by accounting for uptake due to both the concentration and potential gradients across the plasma and mitochondrial membranes. These kinetic parameters were used to model the relationship between MKT-077 uptake and metabolic inhibition. MKT-077-induced changes in oxygen consumption were also characterized in MDA-MB231 human breast carcinoma cells. RESULTS: Cells took up MKT-077 with a time constant of ∼1 hr, and modeling showed that over 90% of intracellular MKT-077 was bound or sequestered, likely by the mitochondria. The uptake resulted in a rapid decrease in oxygen consumption, with a time constant of ∼30 minutes. Surprisingly the change in oxygen consumption was proportional to uptake rate, not cellular concentration. MKT-077 proved a potent metabolic inhibitor, with dose-dependent decreases of 45-73% (p = 0.003. CONCLUSIONS: MKT-077 caused an uptake rate-dependent decrease in cellular metabolism, suggesting potential efficacy for increasing tumor oxygen levels and radiosensitivity in vivo.

  13. Differences in temperature, organic carbon and oxygen consumption among lowland streams

    DEFF Research Database (Denmark)

    Sand-Jensen, K.; Pedersen, N. L.

    2005-01-01

    1. Temperature, organic carbon and oxygen consumption were measured over a year at 13 sites in four lowlands streams within the same region in North Zealand, Denmark with the objectives of determining: (i) spatial and seasonal differences between open streams, forest streams and streams with or w......1. Temperature, organic carbon and oxygen consumption were measured over a year at 13 sites in four lowlands streams within the same region in North Zealand, Denmark with the objectives of determining: (i) spatial and seasonal differences between open streams, forest streams and streams...... the exponential increase of oxygen consumption rate between 4 and 20 °C averaged 0.121 °C-1 (Q10 of 3.35) in 70 measurements and showed no significant variations between seasons and stream sites or correlations with ambient temperature and organic content. 5. Oxygen consumption rate was enhanced downstream...... at ambient temperature by 30-40% and 80-130%, respectively. Faster consumption of organic matter and dissolved oxygen downstream of point sources should increase the likelihood of oxygen stress of the stream biota and lead to the export of less organic matter but more mineralised nutrients to the coastal...

  14. Measurement of oxygen consumption during muscle flaccidity exercise by near-infrared spectroscopy

    Science.gov (United States)

    Fukuda, K.; Fukawa, Y.

    2013-03-01

    Quantitative measurement oxygen consumption in the muscles is important to evaluate the effect of the exercise. Near-infrared spectroscopy (NIRS) is a noninvasive method for measuring muscle oxygenation. However, measurement results are affected by blood volume change due to changes in the blood pressure. In order to evaluate changes in blood volume and to improve measurement accuracy, we proposed a calculation method of three-wavelength measurement with considering the scattering factor and the measurement with monitoring blood flow for measuring the temporal change of the oxygen concentration more precisely. We applied three-wavelength light source (680nm, 808nm and 830nm) for the continued wave measurement. Two detectors (targeted detector and the reference detector) were placed near the target muscle and apart from it. We measured the blood flow by controlling the intravascular pressure and the oxygen consumption with the handgrip exercise in the forearm. The measured results show that the scattering factor contains the artifact at the surface and the blood flow in the artery and the vein in the same phase. The artifact and the blood flow in the same phase are reduced from the oxygenated and the deoxygenated hemoglobin densities. Thus our proposed method is effective for reducing the influence of the artifact and the blood flow in the same phase from the oxygen consumption measurement. Further, it is shown that the oxygen consumption is measured more accurately by subtracting the blood flow measured by the reference detector.

  15. Ventilation and oxygen consumption in the hagfish, Myxine glutinosa L

    DEFF Research Database (Denmark)

    STEFFENSEN, JF; JOHANSEN, K; SINDBERG, CD

    1984-01-01

    Ventilation was measured directly in the hagfish, Myxine glutinosa L., by means of an electro-magnetic blood flowmeter. Ventilatory flow and frequency increased from 0.86 ± 0.27 mlmin-, and 18.2 ± 5.1min-, respectively, at 7°C to 1.70 ± 0.20 mlmin-, and 70.1 ± 9.5min- at 15 C. Standard oxygen...

  16. Effect of a High-intensity Interval Training method on maximum oxygen consumption in Chilean schoolchildren

    Directory of Open Access Journals (Sweden)

    Sergio Galdames-Maliqueo

    2017-12-01

    Full Text Available Introduction: The low levels of maximum oxygen consumption (VO2max evaluated in Chilean schoolchildren suggest the startup of trainings that improve the aerobic capacity. Objective: To analyze the effect of a High-intensity Interval Training method on maximum oxygen consumption in Chilean schoolchildren. Materials and methods: Thirty-two high school students from the eighth grade, who were divided into two groups, were part of the study (experimental group = 16 students and control group = 16 students. The main analyzed variable was the maximum oxygen consumption through the Course Navette Test. A High-intensity Interval training method was applied based on the maximum aerobic speed obtained through the Test. A mixed ANOVA was used for statistical analysis. Results: The experimental group showed a significant increase in the Maximum Oxygen Consumption between the pretest and posttest when compared with the control group (p < 0.0001. Conclusion: The results of the study showed a positive effect of the High-intensity Interval Training on the maximum consumption of oxygen. At the end of the study, it is concluded that High-intensity Interval Training is a good stimulation methodology for Chilean schoolchildren.

  17. Oxygen consumption rate and mitochondrial density in human melanoma monolayer cultures and multicellular spheroids.

    Science.gov (United States)

    Hystad, M E; Rofstad, E K

    1994-05-15

    Rate of oxygen consumption per cell has been shown in previous studies to decrease with increasing depth in the viable rim of multicellular spheroids initiated from rodent cells, human colon-carcinoma cells, and human glioma cells, due to progressive accumulation of quiescent cells during spheroid growth. The purpose of our work was to determine oxygen-consumption profiles in human melanoma spheroids. Monolayer cultures of 4 lines (BEX-c, COX-c, SAX-c, and WIX-c) and spheroid cultures of 2 lines (BEX-c and WIX-c) were subjected to investigation. Spheroids were initiated from monolayer cell cultures and grown in spinner flasks. Rate of oxygen consumption was measured with a Clarke-type electrode. Mitochondrial density was determined by stereological analysis of transmission electron micrographs. Thickness of viable rim and cell packing density were assessed by light microscopy of central spheroid sections. Cell-cycle distribution was determined by analysis of DNA histograms measured by flow cytometry. Cell volume was measured by an electronic particle counter. Rate of oxygen consumption per cell differed by a factor of approximately 1.8 between the 4 cell lines and was positively correlated to total volume of mitochondria per cell. Rate of oxygen consumption per cell and total volume of mitochondria per cell were equal for monolayer cell cultures, 600-microns spheroids and 1,200-microns spheroids of the same line. Mitochondrial density and location in the cell did not differ between cells at the spheroid surface, in the middle of the viable rim and adjacent to the central necrosis. Cell-cycle distribution, cell volume, and cell-packing density in the outer and inner halves of the viable rim were not significantly different. Consequently, the rate of oxygen consumption per cell in inner regions of the viable rim was probably equal to that at the spheroid surface, suggesting that oxygen diffusion distances may be shorter in some melanomas than in many other tumor

  18. Estimate of oxygen consumption and intracellular zinc concentration of human spermatozoa in relation to motility.

    Science.gov (United States)

    Henkel, Ralf R; Defosse, Kerstin; Koyro, Hans-Wilhelm; Weissmann, Norbert; Schill, Wolf-Bernhard

    2003-03-01

    To investigate the human sperm oxygen/energy consumption and zinc content in relation to motility. In washed spermatozoa from 67 ejaculates, the oxygen consumption was determined. Following calculation of the total oxygen consumed by the Ideal Gas Law, the energy consumption of spermatozoa was calculated. In addition, the zinc content of the sperm was determined using an atomic absorption spectrometer. The resulting data were correlated to the vitality and motility. The oxygen consumption averaged 0.24 micromol/10(6) sperm x 24h, 0.28 micromol/10(6) live sperm x 24h and 0.85 micromol/10(6) live motile sperm x 24h. Further calculations revealed that sperm motility was the most energy consuming process (164.31 mJ/10(6) motile spermatozoa x 24h), while the oxygen consumption of the total spermatozoa was 46.06 mJ/10(6) spermatozoa x 24h. The correlation of the oxygen/energy consumption and zinc content with motility showed significant negative correlations (r= -0.759; P<0.0001 and r=-0.441; P<0.0001, respectively). However, when correlating sperm energy consumption with the zinc content, a significant positive relation (r=0.323; P=0.01) was observed. Poorly motile sperm are actually wasting the available energy. Moreover, our data clearly support the "Geometric Clutch Model" of the axoneme function and demonstrate the importance of the outer dense fibers for the generation of sperm motility, especially progressive motility.

  19. Variable ATP yields and uncoupling of oxygen consumption in human brain

    DEFF Research Database (Denmark)

    Gjedde, Albert; Aanerud, Joel; Peterson, Ericka

    2011-01-01

    normalized the metabolic rate to the population average of that region. Coefficients of variation ranged from 10 to 15% in the different regions of the human brain and the normalized regional metabolic rates ranged from 70% to 140% of the population average for each region, equal to a two-fold variation......The distribution of brain oxidative metabolism values among healthy humans is astoundingly wide for a measure that reflects normal brain function and is known to change very little with most changes of brain function. It is possible that the part of the oxygen consumption rate that is coupled...... to ATP turnover is the same in all healthy human brains, with different degrees of uncoupling explaining the variability of total oxygen consumption among people. To test the hypothesis that about 75% of the average total oxygen consumption of human brains is common to all individuals, we determined...

  20. Oxygen Consumption of Tilapia and Preliminary Mass Flows through a Prototype Closed Aquaculture System

    Science.gov (United States)

    Muller, Matthew S.; Bauer, Clarence F.

    1994-01-01

    Performance of NASA's prototype CELSS Breadboard Project Closed Aquaculture System was evaluated by estimating gas exchange quantification and preliminary carbon and nitrogen balances. The total system oxygen consumption rate was 535 mg/hr kg/fish (cv = 30%) when stocked with Tilapia aurea populations (fresh weights of 97 +/- 19 to 147 +/- 36 g/fish for various trials). Oxygen consumption by T. aurea (260 mg/hr kg/fish) contributed to approximately one-half of total system demand. Continuous carbon dioxide quantification methods were analyzed using the,relation of carbon dioxide to oxygen consumption. Overall food conversion rates averaged 18.2 +/- 3.2%. Major pathways for nitrogen and carbon in the system were described with preliminary mass closure of 60-80% and 60% for nitrogen and carbon.

  1. Aerobic composting of waste activated sludge: Kinetic analysis for microbiological reaction and oxygen consumption

    International Nuclear Information System (INIS)

    Yamada, Y.; Kawase, Y.

    2006-01-01

    In order to examine the optimal design and operating parameters, kinetics for microbiological reaction and oxygen consumption in composting of waste activated sludge were quantitatively examined. A series of experiments was conducted to discuss the optimal operating parameters for aerobic composting of waste activated sludge obtained from Kawagoe City Wastewater Treatment Plant (Saitama, Japan) using 4 and 20 L laboratory scale bioreactors. Aeration rate, compositions of compost mixture and height of compost pile were investigated as main design and operating parameters. The optimal aerobic composting of waste activated sludge was found at the aeration rate of 2.0 L/min/kg (initial composting mixture dry weight). A compost pile up to 0.5 m could be operated effectively. A simple model for composting of waste activated sludge in a composting reactor was developed by assuming that a solid phase of compost mixture is well mixed and the kinetics for microbiological reaction is represented by a Monod-type equation. The model predictions could fit the experimental data for decomposition of waste activated sludge with an average deviation of 2.14%. Oxygen consumption during composting was also examined using a simplified model in which the oxygen consumption was represented by a Monod-type equation and the axial distribution of oxygen concentration in the composting pile was described by a plug-flow model. The predictions could satisfactorily simulate the experiment results for the average maximum oxygen consumption rate during aerobic composting with an average deviation of 7.4%

  2. Manual handling methods evaluation based on oxygen consumption

    Science.gov (United States)

    Nurmianto, E.; Ciptomulyono, U.; Suparno; Kromodihardjo, S.; Setijono, H.; Arief, N. A.

    2018-04-01

    Mining industry has become one of the largest industries in Indonesia, now competing in billions dollar market, with numbers people employed. Deliveries of a Return Rolls (RR) involve the use of a hand truck and, in many cases, a shoulder/elbow-mode of carriage. Workers usually prefer to the Gendong (carrying on the small of the back or the hip, supported by the waist and arm) mode or Manggul (carrying on some stuff shoulder) mode, because they feel safer by carrying RR on the shoulder/elbow. In this study, the physiological workload involved in shoulder/elbow-mode carrying was investigated, especially focusing on the effects of load weight and inclination. To measure heart rate and oxygen uptake while carrying on the shoulder/elbow, a laboratory experiment was conducted and safety guidelines for such tasks were proposed, based on the experimental results. Four healthy male subjects performed shoulder/elbow-mode carrying, weight between 20 and 24 kg: (1) on inclination of 10o, (2) 20o and (3) 30o. The results showed that inclination involved an increased physiological burden, and that a load of 24 kg entailed a significantly higher physiological cost than carrying a load of 20 kg. Although shoulder/elbow-mode carrying has some advantages, the worker should be advised to carry a load of less than 20 kg, to avoid a high physiological load. During shoulder/elbow-mode carrying, it is also recommended that a person prepare more training in order to have muscular strength.

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

    Science.gov (United States)

    Gurley, Katelyn; Shang, Yu; Yu, Guoqiang

    2012-07-01

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

  4. Assessing peak aerobic capacity in Dutch law enforcement officers

    Directory of Open Access Journals (Sweden)

    Harriet Wittink

    2015-06-01

    Full Text Available Objectives: To cross-validate the existing peak rate of oxygen consumption (VO2peak prediction equations in Dutch law enforcement officers and to determine whether these prediction equations can be used to predict VO2peak for groups and in a single individual. A further objective was to report normative absolute and relative VO2peak values of a sample of law enforcement officers in the Netherlands. Material and Methods: The peak rate of oxygen consumption (ml×kg–1×min–1 was measured using a maximal incremental bicycle test in 1530 subjects, including 1068 male and 461 female police officers. Validity of the prediction equations for groups was assessed by comparing predicted VO2peak with measured VO2peak using paired t-tests. For individual differences limits of agreement (LoA were calculated. Equations were considered valid for individuals when the difference between measured and predicted VO2peak did not exceed ±1 metabolic equivalent (MET in 95% of individuals. Results: None of the equations met the validity criterion of 95% of individuals having ±1 MET difference or less than the measured value. Limits of agreement (LoAs were large in all predictions. At the individual level, none of the equations were valid predictors of VO2peak (ml×kg–1×min–1. Normative values for Dutch law enforcement officers were presented. Conclusions: Substantial differences between measured and predicted VO2peak (ml×kg–1×min–1 were found. Most tested equations were invalid predictors of VO2peak at group level and all were invalid at individual levels.

  5. Reflex bradycardia does not influence oxygen consumption during hypoxia in the European eel (Anguilla anguilla)

    DEFF Research Database (Denmark)

    Iversen, Nina Kerting; McKenzie, David; Malte, H.

    2010-01-01

    the bradycardia on oxygen consumption (MO2), standard metabolic rate (SMR) and the critical oxygen partial pressure for regulation of SMR in hypoxia (Pcrit) in European eels Anguilla anguilla (mean ± SEM mass 528 ± 36 g; n = 14). Eels were instrumented with a Transonic flow probe around the ventral aorta......Most teleost fish reduce heart rate when exposed to acute hypoxia. This hypoxic bradycardia has been characterised for many fish species, but it remains uncertain whether this reflex contributes to the maintenance of oxygen uptake in hypoxia. Here we describe the effects of inhibiting...

  6. Rate of oxygen consumption of hamster melanoma cells as a factor influencing their radioresistance

    International Nuclear Information System (INIS)

    Pajak, S.; Subczynski, W.; Panz, T.; Lukiewicz, S.

    1980-01-01

    It has been reported in recent years that the level of radiosensitivity of neoplasmic cells in vivo and of sphaeroids in vitro can be modified by controlling their rate of oxygen consumption. Thus, an attempt was made to compare this rate in the case of the melanotic and amelanotic lines of Bomirski hamster melanoma in vitro, as it is known that these two lines distinctly differ in their reactivity to ionizing radiations. The measurements carried out by the use of a new ESR method revealed that pigmented and pigmentless cells consume oxygen at significantly different rates. This means that oxygen utilization may contribute to the overall level of radioresistance of melanoma cells. (author)

  7. A novel approach to the assess biotic oxygen consumption in marine sediment communities

    Science.gov (United States)

    Baranov, Victor; Queiros, Ana; Widdicombe, Stephen; Stephens, Nick; Lessin, Gennadi; Krause, Stefan; Lewandowski, Joerg

    2016-04-01

    Bioturbation , the mixing of the sediment matrix by burrowing animals impacts sediment metabolism, including respiration through redistribution of particulate organics, changes in bacterial biota diversity and acitivity, as well as via burrowing fauna's own metabolism. Bioturbation, reflecting faunal activity, is also a proxy for the general sedimentary ecosystem health, and can be impacted by many of emerging marine environmental issues such as ocean acidification, warming and the occurrence of heat waves. Sedimentary oxygen consumption is often taken as a proxy for the activity of bioturbating fauna, but determining baselines can be difficult because of the confounding effects of other fauna and microbes present in sediments, as well as irnorganic processes that consume oxygen. Limitations therefore exist in current methodologies, and numerous confounding factors are hampering progress in this area. Here, we present novel method for the assessment of sediment respiration which is expected to be affected only by the biogenic oxygen consumption (namely aerobic respiration). As long as tracer reduction "immune" to inorganic oxygen consumption, so that measurements using this method can be used, alongside traditional methods, to decouple biological respiration from inorganic oxygen consumption reactions. The tracer is easily detectable, non-toxic and can be applied in systems with constant oxygen supply. The latter allow for incubation without the need to to work with unsealed experimental units, bringing procedural advantage over traditional methods. Consequently assessed bioturbating fauna is not exposed to hypoxia and additional stress. Here, we had applied system for the first time to investigate impacts of a common North-Atlantic bioturbator, the brittle star Amphiura filiformis, - on respiration of marine sediments. Two series of experiments were conducted with animals and sediment collected from Cawsand Bay, Plymouth, UK Preliminary results show that tracer

  8. Contribution of Respiratory Muscle Oxygen Consumption to Breathing Limitation and Cyspnea

    Directory of Open Access Journals (Sweden)

    Pere Casan

    1997-01-01

    Full Text Available During exercise, the sustainable activity of large muscle groups is limited by oxygen delivery. The purpose of this study was to see whether the oxygen consumption of the respiratory muscles reaches a similar critical value under maximal resistive loading and hyperventilation. A secondary objective was to see whether dyspnea (estimated discomfort experienced with breathing using the Borg 0-10 scale and the oxygen consumption of the respiratory muscles are closely related across conditions. This would be expected if intramuscular sensory nerve fibres stimulated as a consequence of metabolic events contributed to this sensation. In six normal subjects the respiratory muscles were progressively activated by the addition of incremental inspiratory resistive loads to a maximum of 300 cm H20×s/L (SD=66.4, and incremental dead space to a maximum of 2638 mL (SD=452, associated with an increase in ventilation to 75.1 L/min (SD=29.79. Each increment was maintained for 5 mins to allow the measurement of oxygen uptake in a steady state. During resistive loading total oxygen consumption increased from 239 mL/min (SD=38.2 to 299 mL/min (SD=52.3 and dyspnea increased to "very severe" (Borg scale 7.5, SD=1.55. During dead space loading total oxygen consumption increased from 270 mL/min (SD=20.2 to 426 mL/min (SD=81.9 and dyspnea increased to "very severe" (7.1, SD=0.66. Oxygen cost of inspiratory muscle power was 25 mL/watt (95% confidence limits 16.7 to 34.3 with dead space loading and 91 mL/watt (95% confidence limits 54 to 128 with resistive loading. Oxygen consumption did not reach a critical common value in the two types of loading, 60 mL/min (SD 22.3 during maximal resistive loading and 156 mL/min (SD 82.4 during maximal dead space loading (P<0.05. Physiological factors limiting the respiratory muscles are not uniquely related to oxygen consumption and appear to be expressed through the activation of sensory structures, perceptually manifested as

  9. VO(2peak), myocardial hypertrophy, and myocardial blood flow in endurance-trained men.

    Science.gov (United States)

    Laaksonen, Marko S; Heinonen, Ilkka; Luotolahti, Matti; Knuuti, Juhani; Kalliokoski, Kari K

    2014-08-01

    Endurance training induces cardiovascular and metabolic adaptations, leading to enhanced endurance capacity and exercise performance. Previous human studies have shown contradictory results in functional myocardial vascular adaptations to exercise training, and we hypothesized that this may be related to different degrees of hypertrophy in the trained heart. We studied the interrelationships between peak aerobic power (V˙O2peak), myocardial blood flow (MBF) at rest and during adenosine-induced vasodilation, and parameters of myocardial hypertrophy in endurance-trained (ET, n = 31) and untrained (n = 17) subjects. MBF and myocardial hypertrophy were studied using positron emission tomography and echocardiography, respectively. Both V˙O2peak (P negatively with adenosine-stimulated MBF, but when LV mass was taken into account as a partial correlate, this correlation disappeared. The present results show that increased LV mass in ET subjects explains the reduced hyperemic myocardial perfusion in this subject population and suggests that excessive LV hypertrophy has negative effect on cardiac blood flow capacity.

  10. Mechanisms controlling the oxygen consumption in experimentally induced hypochloremic alkalosis in calves.

    Science.gov (United States)

    Cambier, Carole; Clerbaux, Thierry; Amory, Hélène; Detry, Bruno; Florquin, Sandra; Marville, Vincent; Frans, Albert; Gustin, Pascal

    2002-01-01

    The study was carried out on healthy Friesian calves (n = 10) aged between 10 and 30 days. Hypochloremia and alkalosis were induced by intravenous administration of furosemide and isotonic sodium bicarbonate. The venous and arterial blood samples were collected repeatedly. 2,3-diphosphoglycerate (2,3-DPG), hemoglobin and plasmatic chloride concentrations were determined. The red blood cell chloride concentration was also calculated. pH, PCO2 and PO2 were measured in arterial and mixed venous blood. The oxygen equilibrium curve (OEC) was measured in standard conditions. The correspondence of the OEC to the arterial and mixed venous compartments was calculated, taking blood temperature, pH and PCO2 values into account. The oxygen exchange fraction (OEF%), corresponding to the degree of blood desaturation between the arterial and mixed venous compartments and the amount of oxygen released at the tissue level by 100 mL of blood (OEF Vol%) were calculated from the arterial and mixed venous OEC, combined with PO2 and hemoglobin concentration. Oxygen delivery (DO2) was calculated using the arterial oxygen content, the cardiac output measured by thermodilution, and the body weight of the animal. The oxygen consumption (VO2) was derived from the cardiac output, OEF Vol% and body weight values. Despite the plasma hypochloremia, the erythrocyte chloride concentration was not influenced by furosemide and sodium bicarbonate infusion. Due to the alkalosis-induced increase in the 2,3-DPG, the standard OEC was shifted to the right, allowing oxygen to dissociate from hemoglobin more rapidly. These changes opposed the increased affinity of hemoglobin for oxygen induced by alkalosis. Moreover, respiratory acidosis, hemoconcentration, and the slight decrease in the partial oxygen pressure in mixed venous blood (Pvo2) tended to improve the OEF Vol% and maintain the oxygen consumption in a physiological range while the cardiac output, and the oxygen delivery were significantly decreased

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

    NARCIS (Netherlands)

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

    2013-01-01

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

  12. Measurement of oxygen consumption with the Cosmed K2: a comparative study

    NARCIS (Netherlands)

    Forkink, A.; Frings-Dresen, M. H.

    1994-01-01

    An instrument that accurately measures oxygen consumption (VO2) during field performance is valuable for investigations of physiological workload. Cosmed (Rome, Italy) has introduced such an instrument, the Cosmed K2. In this study the Cosmed K2 was compared with the Oxyconbeta (Jaeger, Breda, The

  13. Effects of cadmium chloride on oxygen consumption and gill morphology of Indian flying barb, Esomus danricus.

    Science.gov (United States)

    Das, Suchismita; Gupta, Abhik

    2012-11-01

    Effects of three sub lethal concentrations of cadmium chloride (0.636, 0.063 and 0.006 mg l(-1)) on oxygen consumption and gill morphology in Indian flying barb, Esomus danricus (Hamilton-Buchanan), a teleost fish, were studied. When compared to control, 0.636 mg l(-1) of cadmium chloride after 7,14, 21 and 28 day exposure showed a significant decline in rates of oxygen consumption at 32.98, 28.40, 23.88 and 21.69 ml hr(1) 100 g(-1) of tissue, respectively; while, 0.063 mg l(-1) of cadmium chloride for the same exposure durations showed a significant decline in rates of oxygen consumption at 34.28, 29.30, 28.05 and 26.47 ml hr(1)100 g(-1) of tissue, respectively. However, significant decline in the rate of oxygen consumption at 0.006 mg l(-1) of cadmium chloride could be observed from 21st day of exposure. Gill tissue showed various histopathological changes including epithelial lifting, hyperplasia, mucous secretion, marked leucocyte infiltration in the epithelium after 28 days of cadmium chloride exposure.

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

    Directory of Open Access Journals (Sweden)

    Alexis Espinoza Salinas

    2014-06-01

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

  15. Using carbon emissions, oxygen consumption, and retained energy to calculate dietary ME intake by beef steers

    Science.gov (United States)

    Eight cross-bred beef steers (initial BW = 241 ± 4.10 kg) were used in a 77-d feeding experiment to determine if ME intake can be determined from carbon emissions, oxygen consumption, and energy retention estimates. Steers were housed in a pen equipped with individual feed bunks and animal access w...

  16. Diffusion Limitation and Hyperoxic Enhancement of Oxygen Consumption in Zooxanthellate Sea Anemones, Zoanthids, and Corals.

    Science.gov (United States)

    Shick, J M

    1990-08-01

    Depending on their size and morphology, anthozoan polyps and colonies may be diffusion-limited in their oxygen consumption, even under well-stirred, air-saturated conditions. This is indicated by an enhancement of oxygen consumption under steady-state hyperoxic conditions that simulate the levels of O2 produced photosynthetically by zooxanthellae in the hosts' tissues. Such hyperoxia in the tissues of zooxanthellate species negates the effect of the diffusive boundary layer, and increases the rate of oxygen consumption; thus, in many cases, the rate of respiration measured under normoxia in the dark may not be representative of the rate during the day when the zooxanthellae are photosynthesizing and when the supply of oxygen for respiration is in the tissues themselves, not from the environment. These results have implications in respirometric methodology and in calculating the rate of gross photosynthesis in energetic studies. The activity of cytochrome c oxidase is higher in aposymbiotic than in zooxanthellate specimens of the sea anemone Aiptasia pulchella, and this may indicate a compensation for the relative hypoxia in the tissues of the former, enhancing the delivery of oxygen to the mitochondria from the environment.

  17. Effect of Aerobic Training on Peak Oxygen Uptake Among Seniors Aged 70 or Older: A Meta-Analysis of Randomized Controlled Trials.

    Science.gov (United States)

    Bouaziz, Walid; Kanagaratnam, Lukshe; Vogel, Thomas; Schmitt, Elise; Dramé, Moustapha; Kaltenbach, Georges; Geny, Bernard; Lang, Pierre Olivier

    2018-01-02

    Older adults undergo a progressive decline in cardiorespiratory fitness and functional capacity. This lower peak oxygen uptake (VO 2peak ) level is associated with increased risk of frailty, dependency, loss of autonomy, and mortality from all causes. Regular physical activity and particularly aerobic training (AT) have been shown to contribute to better and healthy aging. We conducted a meta-analysis to measure the exact benefit of AT on VO 2peak in seniors aged 70 years or older. A comprehensive, systematic database search for articles was performed in Embase, Medline, PubMed Central, Science Direct, Scopus, and Web of Science using key words. Two reviewers independently assessed interventional studies for potential inclusion. Ten randomized controlled trials (RCTs) were included totaling 348 seniors aged 70 years or older. Across the trials, no high risk of bias was measured and all considered open-label arms for controls. With significant heterogeneity between the RCTs (all p seniors were, respectively, 1.72 (95% CI: 0.34-3.10) and 1.47 (95% CI: 0.60-2.34). This meta-analysis confirms the AT-associated benefits on VO 2peak in healthy and unhealthy seniors.

  18. Effect of training in minimalist footwear on oxygen consumption during walking and running.

    Science.gov (United States)

    Bellar, D; Judge, L W

    2015-06-01

    The present study sought to examine the effect of 5 weeks of training with minimalist footwear on oxygen consumption during walking and running. Thirteen college-aged students (male n = 7, female n = 6, age: 21.7±1.4 years, height: 168.9±8.8 cm, weight: 70.4±15.8 kg, VO2max: 46.6±6.6 ml·kg(-1)·min(-1)) participated in the present investigation. The participants did not have experience with minimalist footwear. Participants underwent metabolic testing during walking (5.6 km·hr(-1)), light running (7.2 km·hr(-1)), and moderate running (9.6 km·hr(-1)). The participants completed this assessment barefoot, in running shoes, and in minimalist footwear in a randomized order. The participants underwent 5 weeks of training with the minimalist footwear. Afterwards, participants repeated the metabolic testing. Data was analyzed via repeated measures ANOVA. The analysis revealed a significant (F4,32= 7.576, [Formula: see text]=0.408, p ≤ 0.001) interaction effect (time × treatment × speed). During the initial assessment, the minimalist footwear condition resulted in greater oxygen consumption at 9.6 km·hr(-1) (p ≤ 0.05) compared to the barefoot condition, while the running shoe condition resulted in greater oxygen consumption than both the barefoot and minimalist condition at 7.2 and 9.6 km·hr(-1). At post-testing the minimalist footwear was not different at any speed compared to the barefoot condition (p> 0.12). This study suggests that initially minimalist footwear results in greater oxygen consumption than running barefoot, however; with utilization the oxygen consumption becomes similar.

  19. Crouch severity is a poor predictor of elevated oxygen consumption in cerebral palsy.

    Science.gov (United States)

    Steele, Katherine M; Shuman, Benjamin R; Schwartz, Michael H

    2017-07-26

    Children with cerebral palsy (CP) expend more energy to walk compared to typically-developing peers. One of the most prevalent gait patterns among children with CP, crouch gait, is often singled out as especially exhausting. The dynamics of crouch gait increase external flexion moments and the demand on extensor muscles. This elevated demand is thought to dramatically increase energy expenditure. However, the impact of crouch severity on energy expenditure has not been investigated among children with CP. We evaluated oxygen consumption and gait kinematics for 573 children with bilateral CP. The average net nondimensional oxygen consumption during gait of the children with CP (0.18±0.06) was 2.9 times that of speed-matched typically-developing peers. Crouch severity was only modestly related to oxygen consumption, with measures of knee flexion angle during gait explaining only 5-20% of the variability in oxygen consumption. While knee moment and muscle activity were moderately to strongly correlated with crouch severity (r 2 =0.13-0.73), these variables were only weakly correlated with oxygen consumption (r 2 =0.02-0.04). Thus, although the dynamics of crouch gait increased muscle demand, these effects did not directly result in elevated energy expenditure. In clinical gait analysis, assumptions about an individual's energy expenditure should not be based upon kinematics or kinetics alone. Identifying patient-specific factors that contribute to increased energy expenditure may provide new pathways to improve gait for children with CP. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Metabolic changers in oxygen transport in patients with diabetes mellitus type 2. Possibilities for correction

    Directory of Open Access Journals (Sweden)

    I Z Bondarenko

    2009-06-01

    Full Text Available Diabetes mellitus type 2 (DM2 - is an independent predictor of development of heart failure (HF. Spiroergometry - is a method for studying blood gas exchange parameters, commonly used for specification of HF. The purpose: 1. To study features of gas exchange at patients with DM2 without cardiovascular diseases in comparison with healthy control. 2. To estimate efficiency of metoprolol for correction of metabolic disturbances in patients with DM2. Materials and methods: 12 patients with DM2, aged 48,4±8, without history of cardiovascular diseases and 15 control subjects, aged 43,6±8 underwent cardio-pulmonary exercise test on treadmill, according to Bruce protocol. Exercise energy, VO2 peak, MET, VE max, VCO2 production were observed. Results: Patients with DM2 had a reduced exercise duration (p<0,001, lower peak oxygen consumption (p<0,001, VCO2 production and MET (p<0,005, than controls, representing the same state of hypoxia as in patients with ischemic heart disease (IHD of functional class 2. The introduction of metoprolol to patients with DM2 significantly increased exercise duration time and VCO2 production (p<0,005. Conclusions: 1. VO2 consumption in patients with DM2 is decreased to the same levels as in persons without DM2, who have IHD and HF. 2. Changes in oxygen-transport in persons with DM2 may serve as a marker of negative influence of the disease on cardiovascular system status. 3. Metoprolol improves parameters of cardio-respiratory system in patients with DM2.

  1. Fractional Consumption of Liquid Hydrogen and Liquid Oxygen During the Space Shuttle Program

    Science.gov (United States)

    Partridge, Jonathan K.

    2011-01-01

    The Space Shuttle uses the propellants, liquid hydrogen and liquid oxygen, to meet part of the propulsion requirements from ground to orbit. The Kennedy Space Center procured over 25 million kilograms of liquid hydrogen and over 250 million kilograms of liquid oxygen during the 3D-year Space Shuttle Program. Because of the cryogenic nature of the propellants, approximately 55% of the total purchased liquid hydrogen and 30% of the total purchased liquid oxygen were used in the Space Shuttle Main Engines. The balance of the propellants were vaporized during operations for various purposes. This paper dissects the total consumption of liqUid hydrogen and liqUid oxygen and determines the fraction attributable to each of the various processing and launch operations that occurred during the entire Space Shuttle Program at the Kennedy Space Center.

  2. Factors determining the oxygen consumption rate (VO2) on-kinetics in skeletal muscles.

    OpenAIRE

    Korzeniewski, Bernard; Zoladz, Jerzy A

    2004-01-01

    Using a computer model of oxidative phosphorylation developed previously [Korzeniewski and Mazat (1996) Biochem. J. 319, 143-148; Korzeniewski and Zoladz (2001) Biophys. Chem. 92, 17-34], we analyse the effect of several factors on the oxygen-uptake kinetics, especially on the oxygen consumption rate (VO2) and half-transition time t(1/2), at the onset of exercise in skeletal muscles. Computer simulations demonstrate that an increase in the total creatine pool [PCr+/-Cr] (where Cr stands for c...

  3. Positron tomography investigation in humans of the local coupling among CBF, oxygen consumption and glucose utilization

    Energy Technology Data Exchange (ETDEWEB)

    Baron, J C; Rougemont, D; Soussaline, F; Crouzel, C; Bousser, M G; Comar, D

    1983-06-01

    Positron tomography investigation of the local coupling among cerebral blood flow (CBF), oxygen consumption (CMRO/sub 2/) and glucose utilization (CMRGlc) was performed in 5 controls and 6 ischemic stroke patients, using oxygen 15 inhalation technique immediately followed by I.V. injection of /sup 18/F-Fluoro-Desoxyglucose (/sup 18/FDG). The normal couple among all 3 variables was demonstrated; but on the other hand significant disruption of either or both the CBF-CMRGlc and the CMRO/sub 2/-CMRGlc couples was found in all 6 stroke patients. Comments on these new findings were made.

  4. Oxygen delivery and consumption during on-bypass cabg in htea and central analgesia

    Directory of Open Access Journals (Sweden)

    Віталій Олексійович Собокарь

    2015-04-01

    Full Text Available Objective. Despite some advantages, the use of high thoracic epidural anesthesia (HTEA during on-bypass cardiac surgery may be discouraged by fear of adverse hemodynamic effects and associated disturbances of oxygen delivery.Aim. To compare oxygen delivery and consumption during on-bypass coronary artery bypass grafting in settings of HTEA and central analgesia (CA.Methods. 132 patients were assigned into two groups – study group (n=85, where the surgery was performed under HTEA and control group (n=47 - where the surgery was carried out under CA. Using data of transesophageal cardiac ultrasound and blood oximetry blood oxygen delivery (DO2, oxygen consumption (VO2, oxygen extraction coefficient (CEO2 were calculated at four stages of the surgery: after induction, sternotomy, cardiopulmonary bypass and at the end of the surgery.Results. In the initial stages of the surgery DO2 and VO2 were reduced relative to reference values with a tendency to increase in the course of the operation and achievement of the normal or supernormal level (VO2, study group in the final stage. The decrease was due to moderate hypodynamic circulation and hemodilution. After sternotomy DO2 in the study group was higher than that of the control: 356 (279; 458 vs 317±89 ml·min-1·m-2, (р=0,021. After cardiopulmonary bypass oxygen saturation of venous blood (SatvO2, in the study group was 71 ± 9 % compared with 68 ± 10 % in the control group. At the end of the surgery SatvO2 in the study group was 71 (66; 75 vs 59 (53; 70 % in the control (р = 0,005 and oxygen tension of venous blood (РvО2 was correspondingly 39 ± 6 and 33 (30; 38 mm Hg (р = 0,027. Despite the decrease in DO2 and VO2, oxygen extraction indices - CEO2, pvO2, SatvO2, and remained within the reference range, except that of the control group at the end of the surgery. Furthermore, at no stage lactate rise or acid-base deviations was observed in the both groups.Conclusions. In patients operated

  5. In situ measurement of the rate of oxygen consumption by the Callovo-Oxfordian argillaceous rock

    International Nuclear Information System (INIS)

    Vinsot, A.; Lundy, M.; Claret, F.; Wechner, S.

    2012-01-01

    Document available in extended abstract form only. The ventilation of excavated drifts in the Callovo-Oxfordian argillaceous rock induces its exposure to air. The oxygen from air reacts with several reduced mineral species from the rock. It may also react with organic species existing in the rock. The effects of these reactions on the rock mineralogy were observed in the first meters of many boreholes drilled in the Andra's Underground Research Laboratory (URL) drifts at 490 m deep. They generate mainly sulfated and ferric secondary phases. The consequences of these reactions on the evolution of a radioactive waste disposal in such a rock are two folds. First, they will contribute to oxygen consumption and the generation of an anoxic atmosphere in the drifts and vaults after their closure. In addition, they will influence the composition of the water which will later on fill the drifts and vaults. These phenomena are taken into account in the modeling of disposal evolutions at various times and space scales. The main remaining uncertainties regarding these phenomena concern: i) the identification of all the species involved in the oxygen reduction; ii) the reaction kinetics; and iii) the extension of the oxidized zone around the drifts and vaults. The aim of the 'POX experiment' is to reduce these uncertainties. This experiment includes a test dedicated to the quantitative study of oxygen consumption in the Callovo-Oxfordian argillaceous rock. This test was implemented in 2009 in the Andra's URL. After an initial phase during which the rock natural gases and pore water at the test location were observed, the first oxygen injection was performed in July 2011. The experimental concept is based on gas circulation in a borehole. It consists of a 15 m-long and 76 mm-diameter ascending borehole, from which the last 5 m constitute the test interval. The rock surface in the test interval is close to 1 m 2 . The last 6 m of the borehole were cored with argon as a drilling

  6. Relation of Mitochondrial Oxygen Consumption in Peripheral Blood Mononuclear Cells to Vascular Function in Type 2 Diabetes Mellitus

    Science.gov (United States)

    Hartman, Mor-Li; Shirihai, Orian S.; Holbrook, Monika; Xu, Guoquan; Kocherla, Marsha; Shah, Akash; Fetterman, Jessica L.; Kluge, Matthew A.; Frame, Alissa A.; Hamburg, Naomi M.; Vita, Joseph A.

    2014-01-01

    Recent studies have shown mitochondrial dysfunction and increased production of reactive oxygen species in peripheral blood mononuclear cells (PBMC’s) and endothelial cells from patients with diabetes mellitus. Mitochondria oxygen consumption is coupled to ATP production and also occurs in an uncoupled fashion during formation of reactive oxygen species by components of the electron transport chain and other enzymatic sites. We therefore hypothesized that diabetes would be associated with higher total and uncoupled oxygen consumption in PBMC’s that would correlate with endothelial dysfunction. We developed a method to measure oxygen consumption in freshly isolated PBMC’s and applied it to 26 patients with type 2 diabetes mellitus and 28 non-diabetic controls. Basal (192±47 vs. 161±44 pMoles/min, P=0.01), uncoupled (64±16 vs. 53±16 pMoles/min, P=0.007), and maximal (795±87 vs. 715±128 pMoles/min, P=0.01) oxygen consumption rates were higher in diabetic patients compared to controls. There were no significant correlations between oxygen consumption rates and endothelium-dependent flow-mediated dilation measured by vascular ultrasound. Non-endothelium-dependent nitroglycerin-mediated dilation was lower in diabetics (10.1±6.6 vs. 15.8±4.8%, P=0.03) and correlated with maximal oxygen consumption (R= −0.64, P=0.001). In summary, we found that diabetes mellitus is associated with a pattern of mitochondrial oxygen consumption consistent with higher production of reactive oxygen species. The correlation between oxygen consumption and nitroglycerin-mediated dilation may suggest a link between mitochondrial dysfunction and vascular smooth muscle cell dysfunction that merits further study. Finally, the described method may have utility for assessment of mitochondrial function in larger scale observational and interventional studies in humans. PMID:24558030

  7. Effect of remifentanil on mitochondrial oxygen consumption of cultured human hepatocytes.

    Directory of Open Access Journals (Sweden)

    Siamak Djafarzadeh

    Full Text Available During sepsis, liver dysfunction is common, and failure of mitochondria to effectively couple oxygen consumption with energy production has been described. In addition to sepsis, pharmacological agents used to treat septic patients may contribute to mitochondrial dysfunction. This study addressed the hypothesis that remifentanil interacts with hepatic mitochondrial oxygen consumption. The human hepatoma cell line HepG2 and their isolated mitochondria were exposed to remifentanil, with or without further exposure to tumor necrosis factor-α (TNF-α. Mitochondrial oxygen consumption was measured by high-resolution respirometry, Caspase-3 protein levels by Western blotting, and cytokine levels by ELISA. Inhibitory κBα (IκBα phosphorylation, measurement of the cellular ATP content and mitochondrial membrane potential in intact cells were analysed using commercial ELISA kits. Maximal cellular respiration increased after one hour of incubation with remifentanil, and phosphorylation of IκBα occurred, denoting stimulation of nuclear factor κB (NF-κB. The effect on cellular respiration was not present at 2, 4, 8 or 16 hours of incubation. Remifentanil increased the isolated mitochondrial respiratory control ratio of complex-I-dependent respiration without interfering with maximal respiration. Preincubation with the opioid receptor antagonist naloxone prevented a remifentanil-induced increase in cellular respiration. Remifentanil at 10× higher concentrations than therapeutic reduced mitochondrial membrane potential and ATP content without uncoupling oxygen consumption and basal respiration levels. TNF-α exposure reduced respiration of complex-I, -II and -IV, an effect which was prevented by prior remifentanil incubation. Furthermore, prior remifentanil incubation prevented TNF-α-induced IL-6 release of HepG2 cells, and attenuated fragmentation of pro-caspase-3 into cleaved active caspase 3 (an early marker of apoptosis. Our data suggest that

  8. Acute effects of Cu on oxygen consumption and 96 hr-LC 50 values ...

    African Journals Online (AJOL)

    The median lethal copper (Cu) concentration (96 hr-LC50) values for acute Cu toxicity for Tilapia sparrmanii (live mass: 30 ± 8g) in Mooi River hard water of dolomitic origin at 20° C, pH 7.9, was 68.1 µmol l–1. At this 96 hr-LC50 value the specific oxygen consumption rate (∉ O2) decreased by 44.2 (± 2.1) % from a ...

  9. The effect of external dummy transmitters on oxygen consumption and performance of swimming Atlantic cod

    DEFF Research Database (Denmark)

    Steinhausen, M.F.; Andersen, Niels Gerner; Steffensen, J.F.

    2006-01-01

    Decreased critical swimming speed and increased oxygen consumption (Mo-2) was found for externally tagged Atlantic cod Gadus morhua swimming at a high speed of 0 center dot 9 body length (total length, L-Gamma) s(-1). No difference was found in the standard metabolic rate, indicating...... that the higher Mo-2 for tagged cod was due to drag force rather than increased costs to keep buoyancy. (c) 2006 The Authors Journal compilation (c) 2006 The Fisheries Society of the British Isles....

  10. Effect of aeration interval on oxygen consumption and GHG emission during pig manure composting.

    Science.gov (United States)

    Zeng, Jianfei; Yin, Hongjie; Shen, Xiuli; Liu, Ning; Ge, Jinyi; Han, Lujia; Huang, Guangqun

    2018-02-01

    To verify the optimal aeration interval for oxygen supply and consumption and investigate the effect of aeration interval on GHG emission, reactor-scale composting was conducted with different aeration intervals (0, 10, 30 and 50 min). Although O 2 was sufficiently supplied during aeration period, it could be consumed to  0.902), suggesting that lengthening the duration of aeration interval to some extent could effectively reduce GHG emission. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Continuous Real-time Viability Assessment of Kidneys Based on Oxygen Consumption

    Science.gov (United States)

    Weegman, B.P.; Kirchner, V.A.; Scott, W.E.; Avgoustiniatos, E.S.; Suszynski, T.M.; Ferrer-Fabrega, J.; Rizzari, M.D.; Kidder, L.S.; Kandaswamy, R.; Sutherland, D.E.R.; Papas, K.K.

    2010-01-01

    Background Current ex vivo quality assessment of donor kidneys is limited to vascular resistance measurements and histological analysis. New techniques for the assessment of organ quality before transplantation may further improve clinical outcomes while expanding the depleted deceased-donor pool. We propose the measurement of whole organ oxygen consumption rate (WOOCR) as a method to assess the quality of kidneys in real time before transplantation. Methods Five porcine kidneys were procured using a donation after cardiac death (DCD) model. The renal artery and renal vein were cannulated and the kidney connected to a custom-made hypothermic machine perfusion (HMP) system equipped with an inline oxygenator and fiber-optic oxygen sensors. Kidneys were perfused at 8°C, and the perfusion parameters and partial oxygen pressures (pO2) were measured to calculate WOOCR. Results Without an inline oxygenator, the pO2 of the perfusion solution at the arterial inlet and venous outlet diminished to near 0 within minutes. However, once adequate oxygenation was provided, a significant pO2 difference was observed and used to calculate the WOOCR. The WOOCR was consistently measured from presumably healthy kidneys, and results suggest that it can be used to differentiate between healthy and purposely damaged organs. Conclusions Custom-made HMP systems equipped with an oxygenator and inline oxygen sensors can be applied for WOOCR measurements. We suggest that WOOCR is a promising approach for the real-time quality assessment of kidneys and other organs during preservation before transplantation. PMID:20692397

  12. Metabolic cold adaptation of polar fish based on measurements of aerobic oxygen consumption: fact or artefact? Artefact!

    DEFF Research Database (Denmark)

    Steffensen, John Fleng

    2002-01-01

    Whether metabolic cold adaptation in polar fish, based on measurements of aerobic standard metabolic rate, is a fact or an artefact has been a dispute since Holeton asked the question in 1974. So far polar fish had been considered to be metabolically cold adapted because they were reported to have...... a considerably elevated resting oxygen consumption, or standard metabolic rate, compared with oxygen consumption values of tropical or temperate fish extrapolated to similar low polar temperatures. Recent experiments on arctic and Antarctic fish, however, do not show elevated resting aerobic oxygen consumption...

  13. Atrial natriuretic peptide regulates lipid mobilization and oxygen consumption in human adipocytes by activating AMPK

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Sandra C. [Translational Sciences - Translational Medicine, Novartis Institutes for Biomedical Research, Inc., 220 Massachusetts Avenue, Cambridge, MA 02139 (United States); Chau, Mary D.L.; Yang, Qing [Cardiovascular and Metabolism Disease Area, Novartis Institutes for Biomedical Research, Inc., 100 Technology Square, Cambridge, MA 02139 (United States); Gauthier, Marie-Soleil [Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA 02140 (United States); Clairmont, Kevin B.; Wu, Zhidan; Gromada, Jesper [Cardiovascular and Metabolism Disease Area, Novartis Institutes for Biomedical Research, Inc., 100 Technology Square, Cambridge, MA 02139 (United States); Dole, William P., E-mail: bill.dole@novartis.com [Translational Sciences - Translational Medicine, Novartis Institutes for Biomedical Research, Inc., 220 Massachusetts Avenue, Cambridge, MA 02139 (United States)

    2011-07-08

    Highlights: {yields} Treatment of differentiated human adipocytes with atrial natriuretic peptide (ANP) increased lipolysis and oxygen consumption by activating AMP-activated protein kinase (AMPK). {yields} ANP stimulated lipid mobilization by selective activation of the alpha2 subunit of AMPK and increased energy utilization through activation of both the alpha1 and alpha2 subunits of AMPK. {yields} ANP enhanced adipocyte mitochondrial oxidative capacity as evidenced by induction of oxidative mitochondrial genes and increase in oxygen consumption. {yields} Exposure of human adipocytes to fatty acids and (TNF{alpha}) induced insulin resistance and decreased expression of mitochondrial genes which was restored to normal by ANP. -- Abstract: Atrial natriuretic peptide (ANP) has been shown to regulate lipid and carbohydrate metabolism providing a possible link between cardiovascular function and metabolism by mediating the switch from carbohydrate to lipid mobilization and oxidation. ANP exerts a potent lipolytic effect via cGMP-dependent protein kinase (cGK)-I mediated-stimulation of AMP-activated protein kinase (AMPK). Activation of the ANP/cGK signaling cascade also promotes muscle mitochondrial biogenesis and fat oxidation. Here we demonstrate that ANP regulates lipid metabolism and oxygen utilization in differentiated human adipocytes by activating the alpha2 subunit of AMPK. ANP treatment increased lipolysis by seven fold and oxygen consumption by two fold, both of which were attenuated by inhibition of AMPK activity. ANP-induced lipolysis was shown to be mediated by the alpha2 subunit of AMPK as introduction of dominant-negative alpha2 subunit of AMPK attenuated ANP effects on lipolysis. ANP-induced activation of AMPK enhanced mitochondrial oxidative capacity as evidenced by a two fold increase in oxygen consumption and induction of mitochondrial genes, including carnitine palmitoyltransferase 1A (CPT1a) by 1.4-fold, cytochrome C (CytC) by 1.3-fold, and

  14. Atrial natriuretic peptide regulates lipid mobilization and oxygen consumption in human adipocytes by activating AMPK

    International Nuclear Information System (INIS)

    Souza, Sandra C.; Chau, Mary D.L.; Yang, Qing; Gauthier, Marie-Soleil; Clairmont, Kevin B.; Wu, Zhidan; Gromada, Jesper; Dole, William P.

    2011-01-01

    Highlights: → Treatment of differentiated human adipocytes with atrial natriuretic peptide (ANP) increased lipolysis and oxygen consumption by activating AMP-activated protein kinase (AMPK). → ANP stimulated lipid mobilization by selective activation of the alpha2 subunit of AMPK and increased energy utilization through activation of both the alpha1 and alpha2 subunits of AMPK. → ANP enhanced adipocyte mitochondrial oxidative capacity as evidenced by induction of oxidative mitochondrial genes and increase in oxygen consumption. → Exposure of human adipocytes to fatty acids and (TNFα) induced insulin resistance and decreased expression of mitochondrial genes which was restored to normal by ANP. -- Abstract: Atrial natriuretic peptide (ANP) has been shown to regulate lipid and carbohydrate metabolism providing a possible link between cardiovascular function and metabolism by mediating the switch from carbohydrate to lipid mobilization and oxidation. ANP exerts a potent lipolytic effect via cGMP-dependent protein kinase (cGK)-I mediated-stimulation of AMP-activated protein kinase (AMPK). Activation of the ANP/cGK signaling cascade also promotes muscle mitochondrial biogenesis and fat oxidation. Here we demonstrate that ANP regulates lipid metabolism and oxygen utilization in differentiated human adipocytes by activating the alpha2 subunit of AMPK. ANP treatment increased lipolysis by seven fold and oxygen consumption by two fold, both of which were attenuated by inhibition of AMPK activity. ANP-induced lipolysis was shown to be mediated by the alpha2 subunit of AMPK as introduction of dominant-negative alpha2 subunit of AMPK attenuated ANP effects on lipolysis. ANP-induced activation of AMPK enhanced mitochondrial oxidative capacity as evidenced by a two fold increase in oxygen consumption and induction of mitochondrial genes, including carnitine palmitoyltransferase 1A (CPT1a) by 1.4-fold, cytochrome C (CytC) by 1.3-fold, and peroxisome proliferator

  15. Metabolic control over the oxygen consumption flux in intact skeletal muscle: in silico studies.

    Science.gov (United States)

    Liguzinski, Piotr; Korzeniewski, Bernard

    2006-12-01

    It has been postulated previously that a direct activation of all oxidative phosphorylation complexes in parallel with the activation of ATP usage and substrate dehydrogenation (the so-called each-step activation) is the main mechanism responsible for adjusting the rate of ATP production by mitochondria to the current energy demand during rest-to-work transition in intact skeletal muscle in vivo. The present in silico study, using a computer model of oxidative phosphorylation developed previously, analyzes the impact of the each-step-activation mechanism on the distribution of control (defined within Metabolic Control Analysis) over the oxygen consumption flux among the components of the bioenergetic system in intact oxidative skeletal muscle at different energy demands. It is demonstrated that in the absence of each-step activation, the oxidative phosphorylation complexes take over from ATP usage most of the control over the respiration rate and oxidative ATP production at higher (but still physiological) energy demands. This leads to a saturation of oxidative phosphorylation, impossibility of a further acceleration of oxidative ATP synthesis, and dramatic drop in the phosphorylation potential. On the other hand, the each-step-activation mechanism allows maintenance of a high degree of the control exerted by ATP usage over the ATP turnover and oxygen consumption flux even at high energy demands and thus enables a potentially very large increase in ATP turnover. It is also shown that low oxygen concentration shifts the metabolic control from ATP usage to cytochrome oxidase and thus limits the oxidative ATP production.

  16. The effect of neuromuscular blockade on oxygen consumption in sedated and mechanically ventilated pediatric patients after cardiac surgery.

    NARCIS (Netherlands)

    Lemson, J.; Driessen, J.J.; Hoeven, J.G. van der

    2008-01-01

    OBJECTIVE: To measure the effect of intense neuromuscular blockade (NMB) on oxygen consumption (VO(2)) in deeply sedated and mechanically ventilated children on the first day after complex congenital cardiac surgery. DESIGN: Prospective clinical interventional study. SETTING: Pediatric intensive

  17. NODC Standard Format Seabed Oxygen Consumption from In-Situ Sources (F050) Data (1974-1978) (NODC Accession 0014186)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data type contains data from analyses of seabed oxygen consumption determined from measurements over a specified time interval of initial and final dissolved...

  18. Oxygen consumption in Plasmodium berghei-infected murine red cells: a direct spectrophotometric assay in intact erythrocytes.

    Science.gov (United States)

    Deslauriers, R; Moffatt, D J; Smith, I C

    1986-05-29

    A spectrophotometric assay has been devised to measure oxygen consumption non-invasively in intact murine red cells parasitized by Plasmodium berghei. The method uses oxyhemoglobin in the erythrocytes both as a source of oxygen and as an indicator of oxygen consumption. Spectra of intact cells show broad peaks and sloping baselines due to light-scattering. In order to ascertain the number of varying components in the 370-450 nm range, the resolution of the spectra was enhanced using Fourier transforms of the frequency domain spectra. Calculation of oxygen consumption was carried out for two-component systems (oxyhemoglobin, deoxyhemoglobin) using absorbances at 415 and 431 nm. Samples prepared from highly parasitized mice (greater than 80% parasitemia, 5% hematocrit) showed oxygen consumption rates of (4-8) X 10(-8) microliter/cell per h. This rate was not attributable to the presence of white cells or reticulocytes. The rate of oxygen consumption in the erythrocytes is shown to be modulated by various agents: the respiratory inhibitors NaN3 and KCN (1 mM) reduced oxygen consumption 2-3-fold; salicylhydroxamic acid (2.5 mM) caused a 20% reduction in rate and 10 mM NaN3, completely blocked deoxygenation. Antimalarial drugs and metal-chelating agents were also tested. Chloroquine, EDTA and desferal (desferoxamine mesylate) did not decrease the deoxygenation rate of hemoglobin in parasitized cells. Quinacrine, quinine and primaquine reduced the rate of formation of deoxyhemoglobin but also produced substantial quantities of methemoglobin. The lipophilic chelator, 5-hydroxyquinoline, decreased the rate of deoxygenation one-third. The spectrophotometric assay provides a convenient means to monitor oxygen consumption in parasitized red cells, to test the effects of various agents thereon, and potentially to explore possible mechanisms for oxygen utilization.

  19. Quantifying salinity and season effects on eastern oyster clearance and oxygen consumption rates

    Science.gov (United States)

    Casas, S.M.; Lavaud, Romain; LaPeyre, Megan K.; Comeau, L. A.; Filgueira, R.; LaPeyre, Jerome F.

    2018-01-01

    There are few data on Crassostrea virginica physiological rates across the range of salinities and temperatures to which they are regularly exposed, and this limits the applicability of growth and production models using these data. The objectives of this study were to quantify, in winter (17 °C) and summer (27 °C), the clearance and oxygen consumption rates of C. virginica from Louisiana across a range of salinities typical of the region (3, 6, 9, 15 and 25). Salinity and season (temperature and reproduction) affected C. virginica physiology differently; salinity impacted clearance rates with reduced feeding rates at low salinities, while season had a strong effect on respiration rates. Highest clearance rates were found at salinities of 9–25, with reductions ranging from 50 to 80 and 90 to 95% at salinities of 6 and 3, respectively. Oxygen consumption rates in summer were four times higher than in winter. Oxygen consumption rates were within a narrow range and similar among salinities in winter, but varied greatly among individuals and salinities in summer. This likely reflected varying stages of gonad development. Valve movements measured at the five salinities indicated oysters were open 50–60% of the time in the 6–25 salinity range and ~ 30% at a salinity of 3. Reduced opening periods, concomitant with narrower valve gap amplitudes, are in accord with the limited feeding at the lowest salinity (3). These data indicate the need for increased focus on experimental determination of optimal ranges and thresholds to better quantify oyster population responses to environmental changes.

  20. Local cerebral blood flow and local oxygen consumption in prolonged hemiplegic migraine

    International Nuclear Information System (INIS)

    Baron, J.C.; Lebrun-Grandie, P.; Serdaru, M.; Bousser, M.G.; Lhermitte, F.; Cabanis, E.

    1982-09-01

    This work gives the results of a study by positron emission tomography of the cerebral blood flow (CBF), oxygen-extraction rate (O 2 E) and oxygen consumption (CMRO 2 ) during severe and prolonged attack of hemiplegic migraine. The salient facts observed are a high (CBF) in the brain hemisphere affected (ruling out the hypothesis of a persistent cerebral ischemia), together with a collapsed O 2 E (''luxury perfusion'') and especially preservation of the CMRO 2 suggesting a decoupling not only between CBF and CMRO 2 but also between CMRO 2 and functional state of the tissue. Some time after the attack a new study showed the recoupling between CBF and CMRO 2 , but with the latter reduced in the affected hemisphere although the clinical and tomodensitometric state had returned to normal. These new observations should not however be improperly generalised to all migraines, given the unusual characteristics of the disorder in our patient [fr

  1. Assessment of the oxygen consumption in the backfill. Geochemical modelling in a saturated backfill

    International Nuclear Information System (INIS)

    Grandia, Fidel; Domenech, Cristina; Arcos, David; Duro, Lara

    2006-11-01

    The consumption of oxygen in the deep disposal is a major concern due to the ability of this element to corrode the canisters where high level nuclear wastes (HLNW) are disposed. The anoxic conditions initially present in a deep geologic environment are disturbed by the excavation of the repository facilities. After sealing the deposition holes and tunnels using clay-based materials, oxygen remains dissolved in porewater or as a gas phase in the unsaturated pores. The main mechanisms of oxygen depletion that can be considered in the backfill materials are: (1) diffusion into the surrounding rock and (2) kinetic reactions with accessory minerals and organic matter existing in the backfill. In this report, a set of numerical simulations are carried out in one and two dimensions in order to test the effect on the oxygen concentration in the pore water of all these mechanisms. The backfill considered is a 0/70 mixture of MX-80 bentonite and crushed material from the excavation itself. In addition to organic matter, the solid phases with reducing capacity in the backfill are Fe(II)-bearing minerals: pyrite (FeS 2 ) and siderite (FeCO) (as accessory minerals in the bentonite) and Fe-biotite (from the crushed granite). In the simulations, other chemical processes like cation exchange and surface complexation onto clay surfaces, and thermodynamic equilibrium with calcite, gypsum and quartz are considered. Initial composition of porewater is obtained by equilibrating the Forsmark groundwater with the backfill material. The 1D simulation consists of a number of cells with no reactive minerals or organic matter representing granite. The central cell, however, contains oxygen and reactive minerals resembling a backfill. Oxygen is allowed to move only by diffusion. The 2D model simulates the interaction with a backfill of a granitic groundwater flowing through a fracture. Like in the 1D model, the backfill contains oxygen and reactive solids. The results are very similar in

  2. Assessment of the oxygen consumption in the backfill. Geochemical modelling in a saturated backfill

    Energy Technology Data Exchange (ETDEWEB)

    Grandia, Fidel; Domenech, Cristina; Arcos, David; Duro, Lara [Enviros Spain S.L., Barcelona (Spain)

    2006-11-15

    The consumption of oxygen in the deep disposal is a major concern due to the ability of this element to corrode the canisters where high level nuclear wastes (HLNW) are disposed. The anoxic conditions initially present in a deep geologic environment are disturbed by the excavation of the repository facilities. After sealing the deposition holes and tunnels using clay-based materials, oxygen remains dissolved in porewater or as a gas phase in the unsaturated pores. The main mechanisms of oxygen depletion that can be considered in the backfill materials are: (1) diffusion into the surrounding rock and (2) kinetic reactions with accessory minerals and organic matter existing in the backfill. In this report, a set of numerical simulations are carried out in one and two dimensions in order to test the effect on the oxygen concentration in the pore water of all these mechanisms. The backfill considered is a 0/70 mixture of MX-80 bentonite and crushed material from the excavation itself. In addition to organic matter, the solid phases with reducing capacity in the backfill are Fe(II)-bearing minerals: pyrite (FeS{sub 2}) and siderite (FeCO) (as accessory minerals in the bentonite) and Fe-biotite (from the crushed granite). In the simulations, other chemical processes like cation exchange and surface complexation onto clay surfaces, and thermodynamic equilibrium with calcite, gypsum and quartz are considered. Initial composition of porewater is obtained by equilibrating the Forsmark groundwater with the backfill material. The 1D simulation consists of a number of cells with no reactive minerals or organic matter representing granite. The central cell, however, contains oxygen and reactive minerals resembling a backfill. Oxygen is allowed to move only by diffusion. The 2D model simulates the interaction with a backfill of a granitic groundwater flowing through a fracture. Like in the 1D model, the backfill contains oxygen and reactive solids. The results are very similar in

  3. Four Weeks of Off-Season Training Improves Peak Oxygen Consumption in Female Field Hockey Players

    OpenAIRE

    Lindsey T. Funch; Erik Lind; Larissa True; Deborah Van Langen; John T. Foley; James F. Hokanson

    2017-01-01

    The purpose of the study was to examine the changes in peak oxygen consumption ( V ˙O2peak) and running economy (RE) following four-weeks of high intensity training and concurrent strength and conditioning during the off-season in collegiate female field hockey players. Fourteen female student-athletes (age 19.29 ± 0.91 years) were divided into two training groups, matched from baseline V ˙O2peak: High Intensity Training (HITrun; n = 8) and High Intensity Interval Training (HIIT; ...

  4. Molecular mechanisms regulating oxygen transport and consumption in high altitude and hibernating mammals

    DEFF Research Database (Denmark)

    Revsbech, Inge Grønvall

    2016-01-01

    The aim of this thesis is to broaden the knowledge of molecular mechanisms of adjustment in oxygen (O2) uptake, conduction, delivery and consumption in mammals adapted to extreme conditions. For this end, I have worked with animals living at high altitude as an example of environmental hypoxia...... of the repeatedly found adaptive traits in animals living at high altitude and in hibernating mammals during hibernation compared with the active state. Factors that affect O2 affinity of Hb include temperature, H+/CO2 via the Bohr effect as well as Cl- and organic phosphates, in mammals mainly 2...

  5. Oxygen consumption of elite distance runners on an anti-gravity treadmill®.

    Science.gov (United States)

    McNeill, David K P; Kline, John R; de Heer, Hendrick D; Coast, J Richard

    2015-06-01

    Lower body positive pressure (LBPP), or 'anti-gravity' treadmills® have become increasingly popular among elite distance runners. However, to date, few studies have assessed the effect of body weight support (BWS) on the metabolic cost of running among elite runners. This study evaluated how BWS influenced the relationship between velocity and metabolic cost among 6 elite male distance runners. Participants ran three- 16 minute tests consisting of 4 stages of 4 minutes at 8, 7, 6 and 5 min·mile(-1) pace (3.35, 3.84, 4.47 and 5.36 m·s(-1)), while maintaining an aerobic effort (Respiratory Exchange Ratio ≤1.00). One test was run on a regular treadmill, one on an anti-gravity treadmill with 40% BWS and one with 20% BWS being provided. Expired gas data were collected and regression equations used to determine and compare slopes. Significant decreases in oxygen uptake (V̇O2) were found with each increase in BWS (p rate, perceived exertion or directly measured oxygen uptake) should be used to guide training intensity when training on the LBPP treadmill. Key pointsWith increasing amounts of body weight-support (BWS), the slope of the relationship between velocity and oxygen consumption (ΔVO2/Δv) decreases significantly. This means the change in oxygen consumption (VO2) is significantly smaller over a given change in velocity at higher amounts of BWS.There is a non-linear decrease in VO2 with increasing BWS. As such, with each increment in the amount of BWS provided, the reduction in VO2 becomes increasingly smaller.This paper provides first of its kind data on the effects of BWS on the cost of running among highly trained, elite runners. The outcomes of this study are in line with previous findings among non-elite runners.

  6. Influence of radioprotectors on total body weight evolution and on oxygen consumption in lethal dose irradiated animals. (Preliminary study)

    International Nuclear Information System (INIS)

    Fatome, M.; Martine, G.; Bargy, E.; Andrieu, L.

    Comparison of total body weight evolution and oxygen consumption in lethal dose irradiated animals, protected by various well known radioprotective substances, isolated or in mixture, with evolution and consumption of non protected animals irradiated at the same dose and with these of check animals [fr

  7. PET imaging of cerebral perfusion and oxygen consumption in acute ischemic stroke: Relation to outcome

    International Nuclear Information System (INIS)

    Marchal, G.; Serrati, C.; Rioux, P.; Petit-Taboue, M.C.; Viader, F.; Sayette, V. de la; Doze, F. le; Lonchon, P; Derlon, J.M.; Orgogozo, J.M.; Baron, J.C.

    1993-01-01

    The authors used positron emission tomography (PET) to assess the relation between combined imaging of cerebral blood flow and oxygen consumption 5-18 h after first middle cerebral artery (MCA) stroke and neurological outcome at 2 months. All 18 patients could be classified into three visually defined PET patterns of perfusion and oxygen consumption changes. Pattern 1 suggested extensive irreversible damage and was consistently associated with poor outcome. Pattern 2 suggested continuing ischemia and was associated with variable outcome. Pattern 3 with hyperperfusion and little or no metabolic alteration, was associated with excellent recovery, which suggests that early reperfusion is beneficial. This relation between PET and outcome was highly significant. The results suggest that within 5-18 h of stroke onset, PET is a good predictor of outcome in patterns 1 and 3, for which therapy seems limited. The absence of predictive value for pattern 2 suggests that it is due to a reversible ischemic state that is possibly amenable to therapy. These findings may have important implications for acute MCA stroke management and for patients' selection for therapeutic trials

  8. Islet oxygen consumption rate (OCR) dose predicts insulin independence for first clinical islet allotransplants

    Science.gov (United States)

    Kitzmann, JP; O’Gorman, D; Kin, T; Gruessner, AC; Senior, P; Imes, S; Gruessner, RW; Shapiro, AMJ; Papas, KK

    2014-01-01

    Human islet allotransplant (ITx) for the treatment of type 1 diabetes is in phase III clinical registration trials in the US and standard of care in several other countries. Current islet product release criteria include viability based on cell membrane integrity stains, glucose stimulated insulin release (GSIR), and islet equivalent (IE) dose based on counts. However, only a fraction of patients transplanted with islets that meet or exceed these release criteria become insulin independent following one transplant. Measurements of islet oxygen consumption rate (OCR) have been reported as highly predictive of transplant outcome in many models. In this paper we report on the assessment of clinical islet allograft preparations using islet oxygen consumption rate (OCR) dose (or viable IE dose) and current product release assays in a series of 13 first transplant recipients. The predictive capability of each assay was examined and successful graft function was defined as 100% insulin independence within 45 days post-transplant. Results showed that OCR dose was most predictive of CTO. IE dose was also highly predictive, while GSIR and membrane integrity stains were not. In conclusion, OCR dose can predict CTO with high specificity and sensitivity and is a useful tool for evaluating islet preparations prior to clinical ITx. PMID:25131089

  9. Cerebral blood flow and oxygen consumption during ethanol withdrawal in the rat.

    Science.gov (United States)

    Hemmingsen, R; Barry, D I; Hertz, M M; Klinken, L

    1979-09-14

    The ethanol withdrawal syndrome in man and animals is characterized by signs of CNS hyperactivity although a direct measurement of a physiological variable reflecting this CNS hyperactivity has never been performed in untreated man or in animals. We induced ethanol dependence in the rat by means of intragastric intubation with a 20% w/v ethanol solution, thus keeping the animals in a state of continuous severe intoxication for 3--4 days; during the subsequent state of withdrawal characterized by tremor, rigidity, stereotyped movements and general seizures a 25% increase in cerebral oxygen consumption (CMRO2) could be measured; this increase was not due to catecholamines originating from adrenal medulla as adrenomedullectomized animals showed a similar increase in CMRO2 (28%); the withdrawing animals showed a corresponding cerebral blood flow (CBF) increase. The elevated CMRO2 and CBF could be reduced to normal by administration of a beta-adrenergic receptor blocker (propranolol 2 mg/kg i.v.), and hence the increased CMRO2 during ethanol withdrawal could be related to catecholaminergic systems in the brain, e.g. the noradrenergic locus coeruleus system which is anatomically well suited as a general activating system. This interpretation is supported by the earlier neurochemical finding of an increased cerebral noradrenaline turnover during ethanol withdrawal. The exact mechanism underlying the increased cerebral oxygen consumption during ethanol withdrawal and the effect of propranolol on cerebral function during this condition remains to be clarified.

  10. Regional myocardial oxygen consumption estimated by carbon-11 acetate and positron emission tomography before and after repetitive ischemia

    DEFF Research Database (Denmark)

    Kofoed, K F; Hansen, P R; Holm, S

    2000-01-01

    alternating with 5 minutes of reperfusion. Before and after repetitive coronary occlusions, oxygen 15 water/oxygen 15 carbon monoxide (blood flow), and 11C-acetate (oxygen consumption) PET imaging were performed. Left ventricular regional systolic wall thickening was measured with sonomicrometry. Forty......BACKGROUND: Preserved myocardial oxygen consumption estimated by carbon 11-acetate and positron emission tomography (PET) in myocardial regions with chronic but reversibly depressed contractile function in patients with ischemic heart disease have been suggested to be caused by repeated short......-five minutes after the ischemic episodes, systolic ventricular wall thickening was decreased by 90%, whereas myocardial blood flow was reduced by 21% compared with baseline values (P consumption was unaltered compared with the baseline level...

  11. Somatosensory evoked changes in cerebral oxygen consumption measured non-invasively in premature neonates

    Science.gov (United States)

    Roche-Labarbe, Nadege; Fenoglio, Angela; Radakrishnan, Harsha; Kocienski-Filip, Marcia; Carp, Stefan A.; Dubb, Jay; Boas, David A.; Grant, P. Ellen; Franceschini, Maria Angela

    2013-01-01

    The hemodynamic functional response is used as a reliable marker of neuronal activity in countless studies of brain function and cognition. In newborns and infants, however, conflicting results have appeared in the literature concerning the typical response, and there is little information on brain metabolism and functional activation. Measurement of all hemodynamic components and oxygen metabolism is critical for understanding neurovascular coupling in the developing brain. To this end, we combined multiple near infrared spectroscopy techniques to measure oxy- and deoxy-hemoglobin concentrations, cerebral blood volume (CBV), and relative cerebral blood flow (CBF) in the somatosensory cortex of 6 preterm neonates during passive tactile stimulation of the hand. By combining these measures we estimated relative changes in the cerebral metabolic rate of oxygen consumption (rCMRO2). CBF starts increasing immediately after stimulus onset, and returns to baseline before blood volume. This is consistent with the model of pre-capillary arteriole active dilation driving the CBF response, with a subsequent CBV increase influenced by capillaries and veins dilating passively to accommodate the extra blood. rCMRO2 estimated using the steady-state formulation shows a biphasic pattern: an increase immediately after stimulus onset, followed by a post-stimulus undershoot due to blood flow returning faster to baseline than oxygenation. However, assuming a longer mean transit time from the arterial to the venous compartment, due to the immature vascular system of premature infants, reduces the post-stimulus undershoot and increases the flow/consumption ratio to values closer to adult values reported in the literature. We are the first to report changes in local rCBF and rCMRO2 during functional activation in preterm infants. The ability to measure these variables in addition to hemoglobin concentration changes is critical for understanding neurovascular coupling in the developing

  12. Patterns of oxygen consumption during simultaneously occurring elevated metabolic states in the viviparous snake Thamnophis marcianus.

    Science.gov (United States)

    Jackson, Alexander G S; Leu, Szu-Yun; Ford, Neil B; Hicks, James W

    2015-11-01

    Snakes exhibit large factorial increments in oxygen consumption during digestion and physical activity, and long-lasting sub-maximal increments during reproduction. Under natural conditions, all three physiological states may occur simultaneously, but the integrated response is not well understood. Adult male and female checkered gartersnakes (Thamnophis marcianus) were used to examine increments in oxygen consumption (i.e. V̇(O2)) and carbon dioxide production (i.e. V̇(CO2)) associated with activity (Act), digestion (Dig) and post-prandial activity (Act+Dig). For females, we carried out these trials in the non-reproductive state, and also during the vitellogenic (V) and embryogenic (E) phases of a reproductive cycle. Endurance time (i.e. time to exhaustion, TTE) was recorded for all groups during Act and Act+Dig trials. Our results indicate that male and non-reproductive female T. marcianus exhibit significant increments in V̇(O2) during digestion (∼5-fold) and activity (∼9-fold), and that Act+Dig results in a similar increment in V̇(O2) (∼9- to 10-fold). During reproduction, resting V̇(O2) increased by 1.6- to 1.7-fold, and peak increments during digestion were elevated by 30-50% above non-reproductive values, but values associated with Act and Act+Dig were not significantly different from non-reproductive values. During Act+Dig, endurance time remained similar for all of the groups in the present study. Overall, our results indicate that prioritization is the primary pattern of interaction in oxygen delivery exhibited by this species. We propose that the metabolic processes associated with digestion, and perhaps reproduction, are temporarily compromised during activity. © 2015. Published by The Company of Biologists Ltd.

  13. Consumption and efficiency of a passenger car with a hydrogen/oxygen PEFC based hybrid electric drivetrain

    Energy Technology Data Exchange (ETDEWEB)

    Buechi, F.N.; Dietrich, P.; Tsukada, A.; Koetz, R.; Freunberger, S.A. [Paul Scherrer Institut, Electrochemistry Laboratory, CH-5232 Villigen PSI (Switzerland); Paganelli, G.; Laurent, D.; Varenne, P.; Delfino, A.; Magne, P.A.; Walser, D.; Olsommer, D. [Conception et Developpement Michelin, Route Andre-Piller 30, CH-1762 Givisiez (Switzerland)

    2007-08-15

    The main factors for reducing the consumption of a vehicle are reduction of curb weight, air drag and increase in the drivetrain efficiency. Highly efficient drivetrains can be developed based on PEFC technology and curb weight may be limited by an innovative vehicle construction. In this paper, data on consumption and efficiency of a four-place passenger vehicle with a curb weight of 850 kg and an H{sub 2}/O{sub 2} fed PEFC/Supercap hybrid electric powertrain are presented. Hydrogen consumption in the New European Driving Cycle is 0.67 kg H{sub 2}/100 km, which corresponds to a gasoline equivalent consumption of 2.5 l/100 km. When including the energy needed to supply pure oxygen, the calculated consumption increases from 0.67 to 0.69-0.79 kg H{sub 2}/100 km, depending on the method of oxygen production. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  14. Maximal exercise capacity in patients with obstructive sleep apnoea syndrome: A systematic review and meta-analysis.

    Science.gov (United States)

    Mendelson, Monique; Marillier, Mathieu; Bailly, Sébastien; Flore, Patrice; Borel, Jean-Christian; Vivodtzev, Isabelle; Doutreleau, Stéphane; Tamisier, Renaud; Pépin, Jean-Louis; Verges, Samuel

    2018-04-26

    Maximal aerobic capacity is a strong health predictor and peak oxygen consumption (VO 2peak ) is considered a reflection of total body health. No systematic reviews or meta-analysis' to date have synthesised the existing data regarding VO 2peak in patients with obstructive sleep apnoea (OSA).A systematic review of English and French articles using Pubmed/Medline and Embase included studies assessing VO 2peak of OSA patients in mL·kg -1 ·min -1 compared with controls or in % predicted. Two independent reviewers analysed the studies, extracted the data and assessed the quality of evidence.Mean VO 2peak expressed in mL·kg -1 ·min -1 was significantly lower in patients with OSA when compared with controls (mean difference=-2.7 mL·kg -1 ·min -1 ; p<0.001; n=850). This reduction in VO 2peak was found to be larger in non-obese patients (BMI<30 kg·m -2 ). Mean VO 2peak in % predicted was 90.7±21.0% in OSA patients (n=643).OSA patients present reduced maximal aerobic capacity, which can be associated with increased cardiovascular risks and reduced survival in certain patient subgroups. Maximal exercise testing can be useful to characterise functional limitation and to evaluate health status in OSA patients. Registration # CRD42017057319. Copyright ©ERS 2018.

  15. Analysis of swimming performance from physical, physiological, and biomechanical parameters in young swimmers.

    Science.gov (United States)

    Jürimäe, Jaak; Haljaste, Kaja; Cicchella, Antonio; Lätt, Evelin; Purge, Priit; Leppik, Aire; Jürimäe, Toivo

    2007-02-01

    The purpose of this study was to examine the influence of the energy cost of swimming, body composition, and technical parameters on swimming performance in young swimmers. Twenty-nine swimmers, 15 prepubertal (11.9 +/- 0.3 years; Tanner Stages 1-2) and 14 pubertal (14.3 +/- 1.4 years; Tanner Stages 3-4) boys participated in the study. The energy cost of swimming (Cs) and stroking parameters were assessed over maximal 400-m front-crawl swimming in a 25-m swimming pool. The backward extrapolation technique was used to evaluate peak oxygen consumption (VO2peak). A stroke index (SI; m2 . s(-1) . cycles(-1)) was calculated by multiplying the swimming speed by the stroke length. VO2peak results were compared with VO2peak test in the laboratory (bicycle, 2.86 +/- 0.74 L/min, vs. in water, 2.53 +/- 0.50 L/min; R2 = .713; p = .0001). Stepwise-regression analyses revealed that SI (R2 = .898), in-water VO2peak (R2 = .358), and arm span (R2 = .454) were the best predictors of swimming performance. The backward-extrapolation method could be used to assess VO2peak in young swimmers. SI, arm span, and VO2peak appear to be the major determinants of front-crawl swimming performance in young swimmers.

  16. A new method to measure local oxygen consumption in human skeletal muscle during dynamic exercise using near-infrared spectroscopy

    International Nuclear Information System (INIS)

    Binzoni, Tiziano; Cooper, Chris E; Wittekind, Anna L; Beneke, Ralph; Elwell, Clare E; Leung, Terence S; Van De Ville, Dimitri

    2010-01-01

    Near infrared spectroscopy (NIRS) can readily report on changes in blood volume and oxygenation. However, it has proved more problematic to measure real-time changes in blood flow and oxygen consumption. Here we report the development of a novel method using NIRS to measure local oxygen consumption in human muscle. The method utilizes the blood volume changes induced by the muscle pump during rhythmically contracting exercising skeletal muscle. We found that the saturation of the blood during the contraction phase was lower than that during the relaxation phase. The calculated oxygen drop was then divided by the contraction time to generate a value for the muscle oxygen consumption in the optical region of interest. As a test we measured the muscle oxygen consumption in the human vastus lateralis during exercise on a cycle ergometer by 11 trained male athletes (32 ± 11 years old) at 40% and 110% peak aerobic power. We saw an increase from 13.78 µmol 100 g −1 min −1 to 19.72 µmol 100 g −1 min −1 with the increase in power. The measurements are theoretically exempt from usual NIRS confounders such as myoglobin and adipose tissue and could provide a useful tool for studying human physiology

  17. Gait transition and oxygen consumption in swimming striped surfperch Embiotoca lateralis Agassiz

    DEFF Research Database (Denmark)

    Cannas, M.; Schaefer, J.; Domenici, P.

    2006-01-01

    A flow-through respirometer and swim tunnel was used to estimate the gait transition speed (Up-c) of striped surfperch Embiotoca lateralis, a labriform swimmer, and to investigate metabolic costs associated with gait transition. The Up-c was defined as the lowest speed at which fish decrease...... the use of pectoral fins significantly. While the tail was first recruited for manoeuvring at relatively low swimming speeds, the use of the tail at these low speeds [as low as 0·75 body (fork) lengths s-1, LF s-1) was rare (..., either in addition to pectoral fins or during burst-and-coast mode. Oxygen consumption increased exponentially with swimming speeds up to gait transition, and then levelled off. Similarly, cost of transport (CT) decreased with increasing speed, and then levelled off near Up-c. When speeds =Up...

  18. Metformin Targets Brown Adipose Tissue in vivo and Reduces Oxygen Consumption in vitro

    DEFF Research Database (Denmark)

    Breining, Peter; Jensen, Jonas B; Sundelin, Elias I

    2018-01-01

    basic metabolic rate, making BAT an attractive target for treatment of type 2 diabetes. Under the hypothesis that BAT is a metformin target tissue, we investigated in vivo uptake of [11 C]-metformin tracer in mice and studied in vitro effects of metformin on cultured human brown adipocytes. Injected [11......Metformin is the most widely prescribed oral antidiabetic drug worldwide. Despite well-documented beneficial effects on health outcomes in diabetic patients, the target organs that mediate the effects of metformin remain to be established. In adult humans, brown adipose tissue (BAT) can influence...... uptake. Gene expression profiles of OCTs in BAT revealed ample OCT3 expression in both human and mouse BAT. Incubation of a human brown adipocyte cell models with metformin reduced cellular oxygen consumption in a dose dependent manner. Collectively, these results support BAT as a putative metformin...

  19. Moderate dose of watercress and red radish does not reduce oxygen consumption during graded exhaustive exercise

    Directory of Open Access Journals (Sweden)

    Abbas Meamarbashi

    2014-06-01

    Full Text Available Objective: Very recent studies have reported positive effects of dietary nitrate on the oxygen consumption during exercise. This research aimed to study the effect of moderate dose of high-nitrate vegetables, watercress (Nasturtium officinale and red radish (Raphanus sativus compared with a control group on the incremental treadmill exercise test following a standard Bruce protocol controlled by computer. Materials and Methods: Group 1 consumed 100 g watercress (n=11, 109.5 mg nitrate/day, and group 2 consumed 100 g red radish (n=11, mg 173.2 mg nitrate/day for seven days, and control group (n=14 was prohibited from high nitrate intake. Results: During exercise, watercress group showed significant changes in the maximum values of Respiratory Exchange Ratio (RER (p

  20. Taurine Supplementation Improves Functional Capacity, Myocardial Oxygen Consumption, and Electrical Activity in Heart Failure.

    Science.gov (United States)

    Ahmadian, Mehdi; Dabidi Roshan, Valiollah; Ashourpore, Eadeh

    2017-07-04

    Taurine is an amino acid found abundantly in the heart in very high concentrations. It is assumed that taurine contributes to several physiological functions of mammalian cells, such as osmoregulation, anti-inflammation, membrane stabilization, ion transport modulation, and regulation of oxidative stress and mitochondrial protein synthesis. The objective of the current study was to evaluate the effectiveness of taurine supplementation on functional capacity, myocardial oxygen consumption, and electrical activity in patients with heart failure. In a double-blind and randomly designed study, 16 patients with heart failure were assigned to two groups: taurine (TG, n = 8) and placebo (PG, n = 8). TG received 500-mg taurine supplementation three times per day for two weeks. Significant decrease in the values of Q-T segments (p heart failure patients. Together, these findings support the view that taurine improves cardiac function and functional capacity in patients with heart failure. This idea warrants further study.

  1. Value of cerebral blood flow rate and regional oxygen consumption studies in cerebral ischaemia

    Energy Technology Data Exchange (ETDEWEB)

    Clanet, M

    1987-06-18

    Studies of experimentally-induced ischaemia have shown that the intensity of neuronal suffering is related to the fall in perfusion rate. Below a certain level, called functional threshold, cerebral function is reversibly altered, whereas at a lower level (tissue necrosis threshold) the damage inflicted on neurons is irreversible. Between these two thresholds lies a ''penumbra zone''. This concept of thresholds must be mitigated by 2 parameters: duration of ischaemia and selective vulnerability of the various structures affected. Variations in blood flow rate only indirectly affect the state of tissues. Techniques developed from positron emission tomography make it possible to evaluate the metabolic activity of brain tissue in vivo: oxygen consumption (CMRO/sub 2/), oxygen extraction (EO/sub 2/) and glucose consumption (CMRG) which are thus correlated to cerebral blood flow and cerebral blood volume, sometimes also to tissue pH. Normal relations between blood flow rate and metabolism may be altered. Misery perfusion reflects a fall in cerebral blood flow with an increase in EO/sub 2/ and often a decrease in CMRO/sub 2/, whereas luxury perfusion reflects an increase in cerebral blood flow rate with reduction of CMRO/sub 2/, EO/sub 2/ and CMRG. The type of alteration encountered in human ischaemia varies according to the nature of the accident: studies of transient accidents emphasize the different haemodynamic aspects of occlusion of the wider arteries. The metabolic and haemodynamic profiles of established ischaemic accidents vary according to their type and to the time of the study, reflecting the complexity of the physiopathological mechanisms involved; they are frequently associated with metabolic repercussions at a distance from the ischaemic focus, which supports the concept of diaschisis.

  2. The Oxygen Consumption and Metabolic Cost of Walking and Running in Adults With Achondroplasia

    Science.gov (United States)

    Sims, David T.; Onambélé-Pearson, Gladys L.; Burden, Adrian; Payton, Carl; Morse, Christopher I.

    2018-01-01

    The disproportionate body mass and leg length of Achondroplasic individuals may affect their net oxygen consumption (V͘O2) and metabolic cost (C) when walking at running compared to those of average stature (controls). The aim of this study was to measure submaximal V͘O2 and C during a range of set walking speeds (SWS; 0.56 – 1.94 m⋅s-1, increment 0.28 m⋅s-1), set running speeds (SRS; 1.67 – 3.33 m⋅s-1, increment 0.28 m⋅s-1) and a self-selected walking speed (SSW). V͘O2 and C was scaled to total body mass (TBM) and fat free mass (FFM) while gait speed was scaled to leg length using Froude’s number (Fr). Achondroplasic V͘O2TBM and V͘O2FFM were on average 29 and 35% greater during SWS (P 0.05), but CTBM and CFFM at SSW were 23 and 29% higher (P < 0.05) in the Achondroplasic group compared to controls, respectively. V͘O2TBM and V͘O2FFM correlated with Fr for both groups (r = 0.984 – 0.999, P < 0.05). Leg length accounted for the majority of the higher V͘O2TBM and V͘O2FFM in the Achondroplasic group, but further work is required to explain the higher Achondroplasic CTBM and CFFM at all speeds compared to controls. New and Noteworthy: There is a leftward shift of oxygen consumption scaled to total body mass and fat free mass in Achondroplasic adults when walking and running. This is nullified when talking into account leg length. However, despite these scalars, Achondroplasic individuals have a higher walking and metabolic cost compared to age matched non-Achondroplasic individuals, suggesting biomechanical differences between the groups. PMID:29720948

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

    Science.gov (United States)

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

    2014-01-01

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

  4. Value of cerebral blood flow rate and regional oxygen consumption studies in cerebral ischaemia

    International Nuclear Information System (INIS)

    Clanet, M.

    1987-01-01

    Studies of experimentally-induced ischaemia have shown that the intensity of neuronal suffering is related to the fall in perfusion rate. Below a certain level, called functional threshold, cerebral function is reversibly altered, whereas at a lower level (tissue necrosis threshold) the damage inflicted on neurons is irreversible. Between these two thresholds lies a ''penumbra zone''. This concept of thresholds must be mitigated by 2 parameters: duration of ischaemia and selective vulnerability of the various structures affected. Variations in blood flow rate only indirectly affect the state of tissues. Techniques developed from positron emission tomography make it possible to evaluate the metabolic activity of brain tissue in vivo: oxygen consumption (CMRO 2 ), oxygen extraction (EO 2 ) and glucose consumption (CMRG) which are thus correlated to cerebral blood flow and cerebral blood volume, sometimes also to tissue pH. Normal relations between blood flow rate and metabolism may be altered. Misery perfusion reflects a fall in cerebral blood flow with an increase in EO 2 and often a decrease in CMRO 2 , whereas luxury perfusion reflects an increase in cerebral blood flow rate with reduction of CMRO 2 , EO 2 and CMRG. The type of alteration encountered in human ischaemia varies according to the nature of the accident: studies of transient accidents emphasize the different haemodynamic aspects of occlusion of the wider arteries. The metabolic and haemodynamic profiles of established ischaemic accidents vary according to their type and to the time of the study, reflecting the complexity of the physiopathological mechanisms involved; they are frequently associated with metabolic repercussions at a distance from the ischaemic focus, which supports the concept of diaschisis [fr

  5. Força muscular como determinante da eficiência do consumo de oxigênio e da máxima resposta metabólica ao exercício em pacientes com DPOC leve/moderada Muscle strength as a determinant of oxygen uptake efficiency and maximal metabolic response in patients with mild-to-moderate COPD

    Directory of Open Access Journals (Sweden)

    Paulo de Tarso Guerrero Müller

    2012-10-01

    Full Text Available OBJETIVO: Comparar o comportamento de oxygen uptake efficiency slope (OUES, inclinação da eficiência do consumo de oxigênio com o do consumo de oxigênio no pico do exercício (VO2pico. MÉTODOS: Estudo prospectivo transversal envolvendo 21 pacientes (15 homens com DPOC leve/moderada que foram submetidos a espirometria, dinamometria de preensão palmar (DIN, teste cardiopulmonar de exercício e medida de lactato no pico do exercício (LACpico. RESULTADOS: A média de peso foi 66,7 ± 13,6 kg, e a de idade foi 60,7 ± 7,8 anos. Com exceção de VEF1 e relação VEF1/CVF (75,8 ± 18,6 do previsto e 56,6 ± 8,8, respectivamente, as demais variáveis espirométricas foram normais, assim como DIN. As médias, em % do previsto, para VO2pico (93,1 ± 15,4, FC máxima (92,5 ± 10,4 e OUES (99,4 ± 24,4, assim como a da taxa de troca respiratória (1,2 ± 0,1, indicaram estresse metabólico e hemodinâmico importante. A correlação entre o VO2pico e a OUES foi elevada (r = 0,747; p OBJECTIVE: To compare the behavior of the oxygen uptake efficiency slope (OUES with that of oxygen uptake at peak exertion (VO2peak. METHODS: This was a prospective cross-sectional study involving 21 patients (15 men with mild-to-moderate COPD undergoing spirometry, handgrip strength (HGS testing, cardiopulmonary exercise testing, and determination of lactate at peak exertion (LACpeak. RESULTS: Mean weight was 66.7 ± 13.6 kg, and mean age was 60.7 ± 7.8 years. With the exception of FEV1 and FEV1/FVC ratio (75.8 ± 18.6 of predicted and 56.6 ± 8.8, respectively, all spirometric variables were normal, as was HGS. The patients exhibited significant metabolic and hemodynamic stress, as evidenced by the means (% of predicted for VO2peak (93.1 ± 15.4, maximum HR (92.5 ± 10.4, and OUES (99.4 ± 24.4, as well as for the gas exchange rate (1.2 ± 0.1. The correlation between VO2peak and OUES was significant (r = 0.747; p < 0.0001. The correlation between HGS and VO2peak (r

  6. A Stirred Microchamber for Oxygen Consumption Rate Measurements With Pancreatic Islets

    Science.gov (United States)

    Papas, Klearchos K.; Pisania, Anna; Wu, Haiyan; Weir, Gordon C.; Colton, Clark K.

    2010-01-01

    Improvements in pancreatic islet transplantation for treatment of diabetes are hindered by the absence of meaningful islet quality assessment methods. Oxygen consumption rate (OCR) has previously been used to assess the quality of organs and primary tissue for transplantation. In this study, we describe and characterize a stirred microchamber for measuring OCR with small quantities of islets. The device has a titanium body with a chamber volume of about 200 µL and is magnetically stirred and water jacketed for temperature control. Oxygen partial pressure (pO2) is measured by fluorescence quenching with a fiber optic probe, and OCR is determined from the linear decrease of pO2 with time. We demonstrate that measurements can be made rapidly and with high precision. Measurements with βTC3 cells and islets show that OCR is directly proportional to the number of viable cells in mixtures of live and dead cells and correlate linearly with membrane integrity measurements made with cells that have been cultured for 24 h under various stressful conditions. PMID:17497731

  7. Factors determining the oxygen consumption rate (VO2) on-kinetics in skeletal muscles.

    Science.gov (United States)

    Korzeniewski, Bernard; Zoladz, Jerzy A

    2004-05-01

    Using a computer model of oxidative phosphorylation developed previously [Korzeniewski and Mazat (1996) Biochem. J. 319, 143-148; Korzeniewski and Zoladz (2001) Biophys. Chem. 92, 17-34], we analyse the effect of several factors on the oxygen-uptake kinetics, especially on the oxygen consumption rate (VO2) and half-transition time t(1/2), at the onset of exercise in skeletal muscles. Computer simulations demonstrate that an increase in the total creatine pool [PCr+/-Cr] (where Cr stands for creatine and PCr for phosphocreatine) and in glycolytic ATP supply lengthen the half-transition time, whereas increase in mitochondrial content, in parallel activation of ATP supply and ATP usage, in oxygen concentration, in proton leak, in resting energy demand, in resting cytosolic pH and in initial alkalization decrease this parameter. Theoretical studies show that a decrease in the activity of creatine kinase (CK) [displacement of this enzyme from equilibrium during on-transient (rest-to-work transition)] accelerates the first stage of the VO2 on-transient, but slows down the second stage of this transient. It is also demonstrated that a prior exercise terminated a few minutes before the principal exercise shortens the transition time. Finally, it is shown that at a given ATP demand, and under conditions where CK works near the thermodynamic equilibrium, the half-transition time of VO2 kinetics is determined by the amount of PCr that has to be transformed into Cr during rest-to-work transition; therefore any factor that diminishes the difference in [PCr] between rest and work at a given energy demand will accelerate the VO2 on-kinetics. Our conclusions agree with the general idea formulated originally by Easterby [(1981) Biochem. J. 199, 155-161] that changes in metabolite concentrations determine the transition times between different steady states in metabolic systems.

  8. Effects of salinity and pH on the activity and oxygen consumption of Brachionus plicatilis (rotatoria)

    Energy Technology Data Exchange (ETDEWEB)

    Epp, R.W.; Winston, P.W.

    1978-01-01

    Activity and respiratory rates of the rotifer, Brachionus plicatilis, were determined following exposure to pH values of 6.5, 7.5 and 8.5 and to concentrations of 10, 50 and 100 mosm. Changes in the hydrogen-ion concentration had no detectable effect on either activity or metabolism. Acute reduction in osmolarity of the medium resulted in a reduction in oxygen consumption and activity. Both activity and oxygen consumption increased upon acclimatization to osmolarities of 50 and 100 mosm.

  9. Oxygen consumption rate and Na+/K+-ATPase activity in early developmental stages of the sea urchin Paracentrotus lividus Lam.

    Science.gov (United States)

    Tomšić, Sanja; Stanković, Suzana; Lucu, Čedomil

    2011-09-01

    Changes in oxygen consumption rate and Na+/K+-ATPase activity during early development were studied in the sea urchin Paracentrotus lividus Lam. The oxygen consumption rate increased from 0.12 μmol O2 mg protein-1 h-1 in unfertilized eggs to 0.38 μmol O2 mg protein-1 h-1 25 min after fertilization. Specific activity of the Na+/K+-ATPase was significantly stimulated after fertilization, ranging up to 1.07 μmol Pi h-1 mg protein-1 in the late blastula stage and slightly lower values in the early and late pluteus stages.

  10. The oxygen consumption rates of different life stages of the endoparasitic nematode

    Directory of Open Access Journals (Sweden)

    Willie van Aardt

    2010-01-01

    Full Text Available The oxygen consumption rates of different life stages of the endoparasitic nematode, Pratylenchus zeae (Nematoda: Tylenchida during non- and post-anhydrobiosisPratylenchus zeae, widely distributed in tropical and subtropical regions, is an endoparasite in roots of maize and other crop plants. The nematode is attracted to plant roots by CO2 and root exudates and feeds primarily on cells of the root cortex, making channels and openings where the eggs are deposited, with the result that secondary infection occurs due to bacteria and fungi. Nothing is known about the respiration physiology of this nematode and how it manages to survive during dry seasons. To measure the oxygen consumption rate (VO2 of individual P. zeae (less than half a millimeter long, a special measuring technique namely Cartesian diver micro-respirometry was applied. The Cartesian divers were machined from Perspex, and proved to be more accurate to measure VO2 compared with heavier glass divers used in similar experiments on free living nematodes. An accuracy of better than one nanoliter of oxygen consumed per hour was achieved with a single P. zeae inside the diver. Cartesian diver micro-respirometry measurements are based in principle on the manometric changes that occur in a fl otation tube in a manometer set-up when oxygen is consumed by P. zeae and CO2 from the animal is chemically absorbed. VO2 was measured for eggs (length: < 0.05 mm, larvae (length: 0.36 mm and adults (length: 0.47 mm before induction to anhydrobiosis. P. zeae from infected maize roots were extracted and exposed aseptically to in vitro maize root cultures in a grow cabinet at 50 % to 60% relative humidity at 28 ºC using eggs, larvae and adults. VO2 was also measured for post-anhydrobiotic eggs, larvae and adults by taking 50 individuals, eggs and larvae from the culture and placing them in Petri-dishes with 1% agar/water to dry out for 11 days at 28 ºC and 50% relative humidity. The VO2 was measured

  11. AquaResp® — free open-source software for measuring oxygen consumption of resting aquatic animals

    DEFF Research Database (Denmark)

    Svendsen, Morten Bo S.; Skov, Peter Vilhelm; Bushnell, Peter G.

    AquaResp® is a free open-source software program developed to measure the oxygen consumption of aquatic animals using intermittent flow techniques. This free program is based on Microsoft Excel, and uses the MCC Universal Library and a data acquisition board to acquire analogue readings from up...... to four input ports and output control via two digital and two analogue ports. In addition AquaResp can read one COM-port if the oxygen analyser has a RS-232 output signal. The present version of the program has options for parsing data strings generated by two major fibre optic oxygen electrode...

  12. Effects of zilpaterol hydrochloride on methane production, total body oxygen consumption, and blood metabolites in finishing beef steers

    Science.gov (United States)

    An indirect calorimetry experiment was conducted to determine the effects of feeding zilpaterol hydrochloride (ZH) for 20 d on total body oxygen consumption, respiratory quotient, methane production, and blood metabolites in finishing beef steers. Sixteen Angus steers (initial BW = 555 ± 12.7 kg) w...

  13. Effect of the Combination of Ezetimibe and Simvastatin on Gluconeogenesis and Oxygen Consumption in the Rat Liver.

    Science.gov (United States)

    Bracht, Lívia; Caparroz-Assef, Silvana Martins; Bracht, Adelar; Bersani-Amado, Ciomar Aparecida

    2016-06-01

    The aim of this work was to investigate the effects of chronic treatment with the combination of ezetimibe and simvastatin on gluconeogenesis in rat liver. Rats were treated daily for 28 days with the combination of ezetimibe and simvastatin (10/40 mg/kg) by oral gavage. To measure gluconeogenesis and the associated pathways, isolated perfused rat liver was used. In addition, subcellular fractions, such as microsomes and mitochondria, were used for complementary measures of enzymatic activities. Treatment with the combination of simvastatin and ezetimibe resulted in a decrease in gluconeogenesis from pyruvate (-62%). Basal oxygen consumption of the treated animals was higher (+22%) than that of the control rats, but the resulting oxygen consumption that occurred after pyruvate infusion was 43% lower in animals treated with the combination of simvastatin and ezetimibe. Oxygen consumption in the livers from treated animals was completely inhibited by cyanide (electron transport chain inhibitor), but not by proadifen (cytochrome P450 inhibitor). Chronic treatment with ezetimibe/simvastatin decreased the activity of the key enzymes glucose-6-phosphatase and fructose-1,6-bisphosphatase by 59% and 45%, respectively, which is probably the major reason for the decreased gluconeogenesis seen in ezetimibe-/simvastatin-treated rats. It is also possible that part of the effect of this combination on gluconeogenesis and on the oxygen consumption is related to the impairment of mitochondrial energy transduction. © 2015 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

  14. Regional myocardial oxygen consumption estimated by carbon-11 acetate and positron emission tomography before and after repetitive ischemia

    DEFF Research Database (Denmark)

    Kofoed, K F; Hansen, P R; Holm, S

    2011-01-01

    Preserved myocardial oxygen consumption estimated by carbon 11-acetate and positron emission tomography (PET) in myocardial regions with chronic but reversibly depressed contractile function in patients with ischemic heart disease have been suggested to be caused by repeated short episodes of acu...

  15. Modelling benthic oxygen consumption and benthic-pelagic coupling at a shallow station in the southern North Sea

    NARCIS (Netherlands)

    Provoost, P.; Braeckman, U.; Van Gansbeke, D.; Moodley, L.; Soetaert, K.; Middelburg, J.J.; Vanaverbeke, J.

    2013-01-01

    A time-series of benthic oxygen consumption, water-column and sediment chlorophyll concentrations, and temperature in the southern North Sea was subjected to inverse modelling in order to study benthic-pelagic coupling in this coastal marine system. The application of a Markov Chain Monte Carlo

  16. L-NIL prevents renal microvascular hypoxia and increase of renal oxygen consumption after ischemia-reperfusion in rats

    NARCIS (Netherlands)

    Legrand, Matthieu; Almac, Emre; Mik, Egbert G.; Johannes, Tanja; Kandil, Asli; Bezemer, Rick; Payen, Didier; Ince, Can

    2009-01-01

    Legrand M, Almac E, Mik EG, Johannes T, Kandil A, Bezemer R, Payen D, Ince C. L-NIL prevents renal microvascular hypoxia and increase of renal oxygen consumption after ischemia-reperfusion in rats. Am J Physiol Renal Physiol 296: F1109-F1117, 2009. First published February 18, 2009;

  17. Concurrent validity of the PAM accelerometer relative to the MTI Actigraph using oxygen consumption as a reference

    NARCIS (Netherlands)

    Slootmaker, S.M.; Chin A Paw, M.J.M.; Schuit, A.J.; Mechelen, W. van; Koppes, L.L.J.

    2009-01-01

    The purpose of this study was to examine the concurrent validity of the Personal Activity Monitor (PAM) accelerometer relative to the Actigraph accelerometer using oxygen consumption as a reference, and to assess the test-retest reliability of the PAM. Thirty-two fit, normal weight adults (aged

  18. The Oxygen Consumption and Metabolic Cost of Walking and Running in Adults With Achondroplasia

    Directory of Open Access Journals (Sweden)

    David T. Sims

    2018-04-01

    Full Text Available The disproportionate body mass and leg length of Achondroplasic individuals may affect their net oxygen consumption (V͘O2 and metabolic cost (C when walking at running compared to those of average stature (controls. The aim of this study was to measure submaximal V͘O2 and C during a range of set walking speeds (SWS; 0.56 – 1.94 m⋅s-1, increment 0.28 m⋅s-1, set running speeds (SRS; 1.67 – 3.33 m⋅s-1, increment 0.28 m⋅s-1 and a self-selected walking speed (SSW. V͘O2 and C was scaled to total body mass (TBM and fat free mass (FFM while gait speed was scaled to leg length using Froude’s number (Fr. Achondroplasic V͘O2TBM and V͘O2FFM were on average 29 and 35% greater during SWS (P < 0.05 and 12 and 18% higher during SRS (P < 0.05 than controls, respectively. Achondroplasic CTBM and CFFM were 29 and 33% greater during SWS (P < 0.05 and 12 and 18% greater during SRS (P < 0.05 than controls, respectively. There was no difference in SSW V͘O2TBM or V͘O2FFM between groups (P > 0.05, but CTBM and CFFM at SSW were 23 and 29% higher (P < 0.05 in the Achondroplasic group compared to controls, respectively. V͘O2TBM and V͘O2FFM correlated with Fr for both groups (r = 0.984 – 0.999, P < 0.05. Leg length accounted for the majority of the higher V͘O2TBM and V͘O2FFM in the Achondroplasic group, but further work is required to explain the higher Achondroplasic CTBM and CFFM at all speeds compared to controls.New and Noteworthy: There is a leftward shift of oxygen consumption scaled to total body mass and fat free mass in Achondroplasic adults when walking and running. This is nullified when talking into account leg length. However, despite these scalars, Achondroplasic individuals have a higher walking and metabolic cost compared to age matched non-Achondroplasic individuals, suggesting biomechanical differences between the groups.

  19. Maximal oxygen consumption, respiratory volume and some related factors in fire-fighting personnel

    Directory of Open Access Journals (Sweden)

    Touraj Khazraee

    2017-01-01

    Full Text Available Background: Firefighters for difficult activities and rescue of damaged people must be in appropriate physical ability. Maximal oxygen capacity is an indicator for diagnosis of physical ability of workers. This study aimed to assess the cardiorespiratory system and its related factors in firefighters. Methods: This study was conducted on 110 firefighters from various stations. An self-administered questionnaire (respiratory disorders questionnaire, Tuxworth-Shahnavaz step test, and pulmonary function test was used to collection of required data. Average of humidity and temperature was 52% and 17°C, respectively. Background average noise levels were between 55 and 65 dB. Data were analyzed using SPSS software (version 19. Results: The mean age of the study participants was 32 ± 6.2 years. The means of forced vital capacity (FVC, forced expiratory volume in 1 s (FEV1, and FEV1/FVC were 92% ±9.4%, 87% ±9.2%, and 80% ±6.1%, respectively. The participants' mean VO2-max was 2.79 ± 0.29 L/min or 37.34 ± 4.27 ml/kg body weight per minute. The results revealed that weight has a direct association with vital capacity (VC, FVC, and peak expiratory flow. In addition, height was directly associated with VC, FVC, and VO2-max (P < 0.05. However, there was an inverse and significant association between height and FEV1/FVC (r = −0.23,P< 0.05. Height, weight, body mass index, and waist circumference were directly associated with VO2-max. Conclusions: The findings of this study showed that the amount of maximum oxygen consumption is close with the proposed range of this parameter among firefighters in other studies. Furthermore, the results of the study revealed that individuals had normal amounts of lung volume index. This issue can be attributed to the appropriate usage of respiratory masks.

  20. Using micro-patterned sensors and cell self-assembly for measuring the oxygen consumption rate of single cells

    International Nuclear Information System (INIS)

    Etzkorn, James R; Parviz, Babak A; Wu, Wen-Chung; Tian, Zhiyuan; Kim, Prince; Jang, Sei-Hum; Jen, Alex K-Y; Meldrum, Deirdre R

    2010-01-01

    We present a method for self-assembling arrays of live single cells on a glass chip using a photopatternable polymer to form micro-traps. We have studied the single-cell self-assembly method and optimized the process to obtain a 52% yield of single-trapped cells. We also report a method to measure the oxygen consumption rate of a single cell using micro-patterned sensors. These molecular oxygen sensors were fabricated around each micro-trap allowing optical interrogation of oxygen concentration in the immediate environment of the trapped cell. Micromachined micro-wells were then used to seal the trap, sensor and cell in order to determine the oxygen consumption rate of single cells. These techniques reported here add to the collection of tools for performing 'singe-cell' biology. An oxygen consumption rate of 1.05 ± 0.28 fmol min −1 was found for a data set consisting of 25 single A549 cells.

  1. Pectoral fin beat frequency predicts oxygen consumption during spontaneous activity in a labriform swimming fish (Embiotoca lateralis)

    DEFF Research Database (Denmark)

    Tudorache, Christian; Jordan, Anders D.; Svendsen, Jon Christian

    2009-01-01

    The objective of this study was to identify kinematic variables correlated with oxygen consumption during spontaneous labriform swimming. Kinematic variables (swimming speed, change of speed, turning angle, turning rate, turning radius and pectoral fin beat frequency) and oxygen consumption (MO2......) of spontaneous swimming in Embiotoca lateralis were measured in a circular arena using video tracking and respirometry, respectively. The main variable influencing MO2 was pectoral fin beat frequency (r (2) = 0.71). No significant relationship was found between swimming speed and pectoral fin beat frequency....... Complementary to other methods within biotelemetry such as EMG it is suggested that such correlations of pectoral fin beat frequency may be used to measure the energy requirements of labriform swimming fish such as E. lateralis in the field, but need to be taken with great caution since movement and oxygen...

  2. Sulfur Isotope Trends in Archean Microbialite Facies Record Early Oxygen Production and Consumption

    Science.gov (United States)

    Zerkle, A.; Meyer, N.; Izon, G.; Poulton, S.; Farquhar, J.; Claire, M.

    2014-12-01

    The major and minor sulfur isotope composition (δ34S and Δ33S) of pyrites preserved in ~2.65-2.5 billion-year-old (Ga) microbialites record localized oxygen production and consumption near the mat surface. These trends are preserved in two separate drill cores (GKF01 and BH1-Sacha) transecting the Campbellrand-Malmani carbonate platform (Ghaap Group, Transvaal Supergroup, South Africa; Zerkle et al., 2012; Izon et al., in review). Microbialite pyrites possess positive Δ33S values, plotting parallel to typical Archean trends (with a Δ33S/δ34S slope of ~0.9) but enriched in 34S by ~3 to 7‰. We propose that these 34S-enriched pyrites were formed from a residual pool of sulfide that was partially oxidized via molecular oxygen produced by surface mat-dwelling cyanobacteria. Sulfide, carrying the range of Archean Δ33S values, could have been produced deeper within the microbial mat by the reduction of sulfate and elemental sulfur, then fractionated upon reaction with O2 produced by oxygenic photosynthesis. Preservation of this positive 34S offset requires that: 1) sulfide was only partially (50­­-80%) consumed by oxidation, meaning H2S was locally more abundant (or more rapidly produced) than O2, and 2) the majority of the sulfate produced via oxidation was not immediately reduced to sulfide, implying either that the sulfate pool was much larger than the sulfide pool, or that the sulfate formed near the mat surface was transported and reduced in another part of the system. Contrastingly, older microbialite facies (> 2.7 Ga; Thomazo et al., 2013) appear to lack these observed 34S enrichments. Consequently, the onset of 34S enrichments could mark a shift in mat ecology, from communities dominated by anoxygenic photosynthesizers to cyanobacteria. Here, we test these hypotheses with new spatially resolved mm-scale trends in sulfur isotope measurements from pyritized stromatolites of the Vryburg Formation, sampled in the lower part of the BH1-Sacha core. Millimeter

  3. Mitigating an increase of specific power consumption in a cryogenic air separation unit at reduced oxygen production

    Science.gov (United States)

    Singla, Rohit; Chowdhury, Kanchan

    2017-02-01

    Specific power consumed in a Linde double column air separation unit (ASU) increases as the quantity of oxygen produced at a given purity is decreased due to the changes of system requirement or market demand. As the plant operates in part load condition, the specific power consumption (SPC) increases as the total power consumption remains the same. In order to mitigate the increase of SPC at lower oxygen production, the operating pressure of high pressure column (HPC) can be lowered by extending the low pressure column (LPC) by a few trays and adding a second reboiler. As the duty of second reboiler in LPC is increased, the recovery of oxygen decreases with a lowering of the HPC pressure. This results in mitigation of the increase of SPC of the plant. A Medium pressure ASU with dual reboiler that produces pressurised gaseous and liquid products of oxygen and nitrogen is simulated in Aspen Hysys 8.6®, a commercial process simulator to determine SPC at varying oxygen production. The effects of reduced pressure of air feed into the cold box on the size of heat exchangers (HX) are analysed. Operation strategy to obtain various oxygen production rates at varying demand is also proposed.

  4. Effect of limb cooling on peripheral and global oxygen consumption in neonates.

    Science.gov (United States)

    Hassan, I A-A; Wickramasinghe, Y A; Spencer, S A

    2003-03-01

    To evaluate peripheral oxygen consumption (VO(2)) measurements using near infrared spectroscopy (NIRS) with arterial occlusion in healthy term neonates by studying the effect of limb cooling on peripheral and global VO(2). Twenty two healthy term neonates were studied. Peripheral VO(2) was measured by NIRS using arterial occlusion and measurement of the oxyhaemoglobin (HbO(2)) decrement slope. Global VO(2) was measured by open circuit calorimetry. Global and peripheral VO(2) was measured in each neonate before and after limb cooling. In 10 neonates, a fall in forearm temperature of 2.2 degrees C (mild cooling) decreased forearm VO(2) by 19.6% (p forearm temperature of 4 degrees C (moderate cooling) decreased forearm VO(2) by 34.7% (p cooling. The changes are more pronounced with moderate limb cooling when a concomitant rise in global VO(2) is observed. Change in peripheral temperature must be taken into consideration in the interpretation of peripheral VO(2) measurements in neonates.

  5. Long-term fasting decreases mitochondrial avian UCP-mediated oxygen consumption in hypometabolic king penguins.

    Science.gov (United States)

    Rey, Benjamin; Halsey, Lewis G; Dolmazon, Virginie; Rouanet, Jean-Louis; Roussel, Damien; Handrich, Yves; Butler, Patrick J; Duchamp, Claude

    2008-07-01

    In endotherms, regulation of the degree of mitochondrial coupling affects cell metabolic efficiency. Thus it may be a key contributor to minimizing metabolic rate during long periods of fasting. The aim of the present study was to investigate whether variation in mitochondrial avian uncoupling proteins (avUCP), as putative regulators of mitochondrial oxidative phosphorylation, may contribute to the ability of king penguins (Aptenodytes patagonicus) to withstand fasting for several weeks. After 20 days of fasting, king penguins showed a reduced rate of whole animal oxygen consumption (Vo2; -33%) at rest, together with a reduced abundance of avUCP and peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC1-alpha) mRNA in pectoralis muscle (-54%, -36%, respectively). These parameters were restored after the birds had been refed for 3 days. Furthermore, in recently fed, but not in fasted penguins, isolated muscle mitochondria showed a guanosine diphosphate-inhibited, fatty acid plus superoxide-activated respiration, indicating the presence of a functional UCP. It was calculated that variation in mitochondrial UCP-dependent respiration in vitro may contribute to nearly 20% of the difference in resting Vo2 between fed or refed penguins and fasted penguins measured in vivo. These results suggest that the lowering of avUCP activity during periods of long-term energetic restriction may contribute to the reduction in metabolic rate and hence the ability of king penguins to face prolonged periods of fasting.

  6. Plasma osmolality and oxygen consumption of perch Perca fluviatilis in response to different salinities and temperatures

    DEFF Research Database (Denmark)

    Christensen, Emil Aputsiaq Flindt; Svendsen, Morten Bo Søndergaard; Steffensen, John Fleng

    2017-01-01

    with salinity at 10 and 20° C. Maximum metabolic rate (MMR) and aerobic scope was lowest at salinity of 15 at 5° C, yet at 20° C, they were lowest at a salinity of 0. A cost of osmoregulation (SMR at a salinity of 0 and 15 compared with SMR at a salinity of 10) could only be detected at a salinity of 15 at 20...... of osmoregulation (28%) at a salinity of 15 at 20° C indicates that the cost of osmoregulation in P. fluviatilis increases with temperature under hyperosmotic conditions and a power analysis showed that the cost of osmoregulation could be lower than 12·5% under other environmental conditions. The effect of salinity......The present study determined the blood plasma osmolality and oxygen consumption of the perch Perca fluviatilis at different salinities (0, 10 and 15) and temperatures (5, 10 and 20° C). Blood plasma osmolality increased with salinity at all temperatures. Standard metabolic rate (SMR) increased...

  7. Selection for high and low oxygen consumption-induced differences in maintenance energy requirements of mice.

    Science.gov (United States)

    Darhan, Hongyu; Kikusato, Motoi; Toyomizu, Masaaki; Roh, Sang-Gun; Katoh, Kazuo; Sato, Masahiro; Suzuki, Keiichi

    2017-07-01

    Maintenance energy requirements (MER) of mice selected for high (H) or low (L) oxygen consumption (OC) were compared. Forty-four mice from H and L OC lines were weaned at 3 weeks and divided into four experimental groups: group A were sacrificed at 4 weeks; group B were fed ad libitum, and groups C and D were fed 2.8 and 2.4 g/day, respectively, from 4 to 8 weeks of age. Groups B-D were sacrificed at 8 weeks. Chemical components were estimated for all groups. MER was estimated using a model that partitioned metabolizable energy intake into that used for maintenance, and protein and fat deposition. The feed conversion ratio for the B group was significantly higher in the H than in the L line. Feed intake for metabolic energy content per metabolic body size was significantly also higher in the H line, whereas accumulated energy content per metabolic body size was significantly higher in the L line. MER of the H line was greater than that of the L line (P < 0.10). These results suggest that selection for H or L OC produced differences in chemical components, feed efficiency, and MER between the H and L lines. © 2016 Japanese Society of Animal Science.

  8. Hypoxic training increases maximal oxygen consumption in Thoroughbred horses well-trained in normoxia.

    Science.gov (United States)

    Ohmura, Hajime; Mukai, Kazutaka; Takahashi, Yuji; Takahashi, Toshiyuki; Jones, James H

    2017-01-01

    Hypoxic training is effective for improving athletic performance in humans. It increases maximal oxygen consumption (V̇O 2 max) more than normoxic training in untrained horses. However, the effects of hypoxic training on well-trained horses are unclear. We measured the effects of hypoxic training on V̇O 2 max of 5 well-trained horses in which V̇O 2 max had not increased over 3 consecutive weeks of supramaximal treadmill training in normoxia which was performed twice a week. The horses trained with hypoxia (15% inspired O 2 ) twice a week. Cardiorespiratory valuables were analyzed with analysis of variance between before and after 3 weeks of hypoxic training. Mass-specific V̇O 2 max increased after 3 weeks of hypoxic training (178 ± 10 vs. 194 ± 12.3 ml O 2 (STPD)/(kg × min), Phorses, at least for the durations of time evaluated in this study. Training while breathing hypoxic gas may have the potential to enhance normoxic performance of Thoroughbred horses.

  9. Temperature induced variation in oxygen consumption of juvenile and adult stage of the dog conch Laevistrombus canarium (Linnaeus 1758)

    Science.gov (United States)

    Hassan, Wan Nurul Husna Wan; Amin, S. M. Nurul; Ghaffar, Mazlan Abd; Cob, Zaidi Che

    2015-09-01

    Laevistrombus canarium Linnaeus, 1758 is one of the important edible sea snail within the western Johor Straits, Malaysia. In this study, the impact of temperature on oxygen consumption (MO2) of L. canarium based on their ontogenetic changes (juvenile and adult) was measured in the laboratory condition at 22.0, 26.0, 30.0 and 34.0°C. Measurement of MO2 were taken every 1 s for 60 min on 4.20 - 34.00 g dog conch using respirometry chamber. All experiments were carried out in static conditions in five replicates with one snail per chambers. The results of oxygen consumption showed that juvenile dog conch respired at the rate of 0.163 ml h-1 and adult respired at the rate of 0.119 ml h-1. Consequently, the oxygen consumption in juvenile and adult dog conch was expressed as a total energy spends. The results indicates that total energy spend for oxygen consumed (ml h-1) of L. canarium at different temperature regimes (22.0 to 34.0°C) slightly increased over time period (0.63 ± 0.12 to 3.24 ± 0.05 J h-1) respectively. This finding of the present study suggested L. canarium is well adapted for life in high temperature environment.

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

    Science.gov (United States)

    Nelson, J A

    2016-01-01

    Accounting for energy use by fishes has been taking place for over 200 years. The original, and continuing gold standard for measuring energy use in terrestrial animals, is to account for the waste heat produced by all reactions of metabolism, a process referred to as direct calorimetry. Direct calorimetry is not easy or convenient in terrestrial animals and is extremely difficult in aquatic animals. Thus, the original and most subsequent measurements of metabolic activity in fishes have been measured via indirect calorimetry. Indirect calorimetry takes advantage of the fact that oxygen is consumed and carbon dioxide is produced during the catabolic conversion of foodstuffs or energy reserves to useful ATP energy. As measuring [CO2 ] in water is more challenging than measuring [O2 ], most indirect calorimetric studies on fishes have used the rate of O2 consumption. To relate measurements of O2 consumption back to actual energy usage requires knowledge of the substrate being oxidized. Many contemporary studies of O2 consumption by fishes do not attempt to relate this measurement back to actual energy usage. Thus, the rate of oxygen consumption (M˙O2 ) has become a measurement in its own right that is not necessarily synonymous with metabolic rate. Because all extant fishes are obligate aerobes (many fishes engage in substantial net anaerobiosis, but all require oxygen to complete their life cycle), this discrepancy does not appear to be of great concern to the fish biology community, and reports of fish oxygen consumption, without being related to energy, have proliferated. Unfortunately, under some circumstances, these measures can be quite different from one another. A review of the methodological history of the two measurements and a look towards the future are included. © 2016 The Fisheries Society of the British Isles.

  11. Predicted consequences of diabetes and SGLT inhibition on transport and oxygen consumption along a rat nephron

    Science.gov (United States)

    Vallon, Volker; Edwards, Aurélie

    2016-01-01

    Diabetes increases the reabsorption of Na+ (TNa) and glucose via the sodium-glucose cotransporter SGLT2 in the early proximal tubule (S1-S2 segments) of the renal cortex. SGLT2 inhibitors enhance glucose excretion and lower hyperglycemia in diabetes. We aimed to investigate how diabetes and SGLT2 inhibition affect TNa and sodium transport-dependent oxygen consumption QO2active along the whole nephron. To do so, we developed a mathematical model of water and solute transport from the Bowman space to the papillary tip of a superficial nephron of the rat kidney. Model simulations indicate that, in the nondiabetic kidney, acute and chronic SGLT2 inhibition enhances active TNa in all nephron segments, thereby raising QO2active by 5–12% in the cortex and medulla. Diabetes increases overall TNa and QO2active by ∼50 and 100%, mainly because it enhances glomerular filtration rate (GFR) and transport load. In diabetes, acute and chronic SGLT2 inhibition lowers QO2active in the cortex by ∼30%, due to GFR reduction that lowers proximal tubule active TNa, but raises QO2active in the medulla by ∼7%. In the medulla specifically, chronic SGLT2 inhibition is predicted to increase QO2active by 26% in late proximal tubules (S3 segments), by 2% in medullary thick ascending limbs (mTAL), and by 9 and 21% in outer and inner medullary collecting ducts (OMCD and IMCD), respectively. Additional blockade of SGLT1 in S3 segments enhances glucose excretion, reduces QO2active by 33% in S3 segments, and raises QO2active by SGLT2 blockade in diabetes lowers cortical QO2active and raises medullary QO2active, particularly in S3 segments. PMID:26764207

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Klearchos K Papas

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

  14. A computational model for simulating solute transport and oxygen consumption along the nephrons

    Science.gov (United States)

    Vallon, Volker; Edwards, Aurélie

    2016-01-01

    The goal of this study was to investigate water and solute transport, with a focus on sodium transport (TNa) and metabolism along individual nephron segments under differing physiological and pathophysiological conditions. To accomplish this goal, we developed a computational model of solute transport and oxygen consumption (QO2) along different nephron populations of a rat kidney. The model represents detailed epithelial and paracellular transport processes along both the superficial and juxtamedullary nephrons, with the loop of Henle of each model nephron extending to differing depths of the inner medulla. We used the model to assess how changes in TNa may alter QO2 in different nephron segments and how shifting the TNa sites alters overall kidney QO2. Under baseline conditions, the model predicted a whole kidney TNa/QO2, which denotes the number of moles of Na+ reabsorbed per moles of O2 consumed, of ∼15, with TNa efficiency predicted to be significantly greater in cortical nephron segments than in medullary segments. The TNa/QO2 ratio was generally similar among the superficial and juxtamedullary nephron segments, except for the proximal tubule, where TNa/QO2 was ∼20% higher in superficial nephrons, due to the larger luminal flow along the juxtamedullary proximal tubules and the resulting higher, flow-induced transcellular transport. Moreover, the model predicted that an increase in single-nephron glomerular filtration rate does not significantly affect TNa/QO2 in the proximal tubules but generally increases TNa/QO2 along downstream segments. The latter result can be attributed to the generally higher luminal [Na+], which raises paracellular TNa. Consequently, vulnerable medullary segments, such as the S3 segment and medullary thick ascending limb, may be relatively protected from flow-induced increases in QO2 under pathophysiological conditions. PMID:27707705

  15. Preliminary observations in systemic oxygen consumption during targeted temperature management after cardiac arrest.

    Science.gov (United States)

    Uber, Amy; Grossestreuer, Anne V; Ross, Catherine E; Patel, Parth V; Trehan, Ambica; Donnino, Michael W; Berg, Katherine M

    2018-06-01

    Limited data suggests low oxygen consumption (VO 2 ), driven by mitochondrial injury, is associated with mortality after cardiac arrest. Due to the challenges of measurement in the critically ill, post-arrest metabolism remains poorly characterized. We monitored VO 2 , carbon dioxide production (VCO 2 ) and the respiratory quotient (RQ) in post-arrest patients and explored associations with outcome. Using a gas exchange monitor, we measured continuous VO 2 and VCO 2 in post- arrest patients treated with targeted temperature management. We used area under the curve and medians over time to evaluate the association between VO 2 , VCO 2 , RQ and the VO 2 :lactate ratio with survival. In 17 patients, VO 2 in the first 12 h after return of spontaneous circulation (ROSC) was associated with survival (median in survivors 3.35 mL/kg/min [2.98,3.88] vs. non-survivors 2.61 mL/kg/min [2.21,2.94], p = .039). This did not persist over 24 h. The VO 2 :lactate ratio was associated with survival (median in survivors 1.4 [IQR: 1.1,1.7] vs. non-survivors 0.8 [IQR: 0.6,1.2] p  0.7 (p = .131). VCO 2 was not associated with survival. There was a significant association between VO 2 and mortality in the first 12 h after ROSC, but not over 24 h. Lower VO 2: lactate ratio was associated with mortality. A large percentage of patients had RQs below physiologic norms. Further research is needed to explore whether these parameters could have true prognostic value or be a potential treatment target. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Four Weeks of Off-Season Training Improves Peak Oxygen Consumption in Female Field Hockey Players

    Directory of Open Access Journals (Sweden)

    Lindsey T. Funch

    2017-11-01

    Full Text Available The purpose of the study was to examine the changes in peak oxygen consumption ( V ˙O2peak and running economy (RE following four-weeks of high intensity training and concurrent strength and conditioning during the off-season in collegiate female field hockey players. Fourteen female student-athletes (age 19.29 ± 0.91 years were divided into two training groups, matched from baseline V ˙O2peak: High Intensity Training (HITrun; n = 8 and High Intensity Interval Training (HIIT; n = 6. Participants completed 12 training sessions. HITrun consisted of 30 min of high-intensity running, while HIIT consisted of a series of whole-body high intensity Tabata-style intervals (75–85% of age predicted maximum heart rate for a total of four minutes. In addition to the interval training, the off-season training included six resistance training sessions, three team practices, and concluded with a team scrimmage. V ˙O2peak was measured pre- and post-training to determine the effectiveness of the training program. A two-way mixed (group × time ANOVA showed a main effect of time with a statistically significant difference in V ˙O2peak from pre- to post-testing, F(1, 12 = 12.657, p = 0.004, partial η2 = 0.041. Average (±SD V ˙O2peak increased from 44.64 ± 3.74 to 47.35 ± 3.16 mL·kg−1·min−1 for HIIT group and increased from 45.39 ± 2.80 to 48.22 ± 2.42 mL·kg−1·min−1 for HITrun group. Given the similar improvement in aerobic power, coaches and training staff may find the time saving element of HIIT-type conditioning programs attractive.

  17. Characterization of Adipose Tissue Product Quality Using Measurements of Oxygen Consumption Rate.

    Science.gov (United States)

    Suszynski, Thomas M; Sieber, David A; Mueller, Kathryn; Van Beek, Allen L; Cunningham, Bruce L; Kenkel, Jeffrey M

    2018-03-14

    Fat grafting is a common procedure in plastic surgery but associated with unpredictable graft retention. Adipose tissue (AT) "product" quality is affected by the methods used for harvest, processing and transfer, which vary widely amongst surgeons. Currently, there is no method available to accurately assess the quality of AT. In this study, we present a novel method for the assessment of AT product quality through direct measurements of oxygen consumption rate (OCR). OCR has exhibited potential in predicting outcomes following pancreatic islet transplant. Our study aim was to reapportion existing technology for its use with AT preparations and to confirm that these measurements are feasible. OCR was successfully measured for en bloc and postprocessed AT using a stirred microchamber system. OCR was then normalized to DNA content (OCR/DNA), which represents the AT product quality. Mean (±SE) OCR/DNA values for fresh en bloc and post-processed AT were 149.8 (± 9.1) and 61.1 (± 6.1) nmol/min/mg DNA, respectively. These preliminary data suggest that: (1) OCR and OCR/DNA measurements of AT harvested using conventional protocol are feasible; and (2) standard AT processing results in a decrease in overall AT product quality. OCR measurements of AT using existing technology can be done and enables accurate, real-time, quantitative assessment of the quality of AT product prior to transfer. The availability and further validation of this type of assay could enable optimization of fat grafting protocol by providing a tool for the more detailed study of procedural variables that affect AT product quality.

  18. Consumo de oxigênio pós-exercícios de força e aeróbio: efeito da ordem de execução Strength and aerobic post-exercises oxygen consumption: effect of the order of performance

    Directory of Open Access Journals (Sweden)

    Fábio Santos de Lira

    2007-12-01

    do EPOC é bastante reduzido (≅ 15kcal.Concurrent training is a strategy which has been used with the purpose to maximize energy expenditure both during and after exercise by exacerbation of excess post-exercise oxygen consumption (EPOC. However, little is known about the influence of the order of performance of exercises on EPOC. The aim of the present study was to verify the influence of type (aerobic, strength and concurrent and order (aerobic + strength or strength + aerobic of exercise on excessive post-exercise oxygen consumption. Eight male volunteers (age: 24 ± 2 years; weight mass: 75.4 ± 3.7 kg; and height: 179 ± 3.0 cm, with experience in aerobic and strength training were studied. The subjects were submitted to a test for the determination of the VO2peak (57.0 ± 2.9 ml/kg/min and test of 1-RM for the exercises of bench press (68 ± 2 kg, lat pull down (64 ± 3 kg, leg extension (51 ± 3 kg and leg curl (38 ± 3 kg. Aerobic training was conducted for 30 minutes at 90% of the anaerobic threshold velocity (10.3 ± 2.2 km. The protocol strength training corresponded to 70% of 1RM, divided in three sets of 12 repetitions. Oxygen consumption (VO2 was measured at rest (R and after the following sessions: aerobic (A, strength (S, aerobic-strength (A + S and strength-aerobic (S + A, using indirect calorimetry for 30 minutes, which were divided in three time intervals: T1 (0-10 minutes, T2 (11-20 minutes and T3 (the 21-30 minutes. The comparison of the VO2 among the different situations (R, A, S, A + S and S + A for each period of time (0-10, 11-20; 21-30 min was determined by one-way ANOVA with repeated measurements, followed by Tukey test. In T1, the VO2 of the different sessions was increased in relation to R. During T2, the VO2 of situations S, A + S and S + A was increased in relation to R. In T3, only A + S resulted in EPOC. The results indicate that exercise order influences EPOC time. However, in 30 minutes the caloric expenditure caused by EPOC was

  19. Oxygen uptake response to cycle ergometry in post-acute stroke patients with different severity of hemiparesis.

    Science.gov (United States)

    Chen, Chun-Kai; Weng, Ming-Cheng; Chen, Tien-Wen; Huang, Mao-Hsiung

    2013-11-01

    This study evaluated the impact of severity of hemiparesis on oxygen uptake (VO2) response in post-acute stroke patients. Sixty-four patients with a mean poststroke interval of 8.6 ± 3.8 days underwent a ramp cardiopulmonary exercise test on a cycling ergometer to volitional termination. Mean peak VO2 (VO2peak) and work efficiency (ΔVO2/ΔWR) were measured by open-circuit spirometry during standard upright ergometer cycling. Severity of the hemiparetic lower limb was assessed by Brunnstrom's motor recovery stages lower extremity (BMRSL). VO2peak was 10% lower in hemiparetic leg with BMRSL V than in that with BMRSL VI, 20% lower in BMRSL IV, and 50% lower in BMRSL III. ΔVO2/ΔWR was higher for the group with increased BMRSL. The relations were consistent after adjustment for age, sex, body mass index, stroke type, hemiparetic side, modified Ashworth Scale, time poststroke, comorbidities, and medications. Our findings revealed that O2peak is dependent on the severity of hemiparesis in leg, and along with ΔO2/ΔWR closely related to the severity of hemiparesis in post-acute stroke patients, regardless of the types and locations of lesion after stroke, as well as the differences in comorbidities and medications. Copyright © 2013. Published by Elsevier B.V.

  20. Effect of high-intensity training versus moderate training on peak oxygen uptake and chronotropic response in heart transplant recipients

    DEFF Research Database (Denmark)

    Dall, C H; Snoer, M; Christensen, S

    2014-01-01

    In heart transplant (HTx) recipients, there has been reluctance to recommend high-intensity interval training (HIIT) due to denervation and chronotropic impairment of the heart. We compared the effects of 12 weeks' HIIT versus continued moderate exercise (CON) on exercise capacity and chronotropic...... response in stable HTx recipients >12 months after transplantation in a randomized crossover trial. The study was completed by 16 HTx recipients (mean age 52 years, 75% males). Baseline peak oxygen uptake (VO2peak ) was 22.9 mL/kg/min. HIIT increased VO2peak by 4.9 ± 2.7 mL/min/kg (17%) and CON by 2.6 ± 2.......2 mL/kg/min (10%) (significantly higher in HIIT; p HIIT, systolic blood pressure decreased significantly (p = 0.037) with no significant change in CON (p = 0.241; between group difference p = 0.027). Peak heart rate (HRpeak ) increased significantly by 4.3 beats per minute (p = 0...

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

    Science.gov (United States)

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

    2016-07-01

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

  2. FORMING SELF-ASSEMBLED CELL ARRAYS AND MEASURING THE OXYGEN CONSUMPTION RATE OF A SINGLE LIVE CELL.

    Science.gov (United States)

    Etzkorn, James R; McQuaide, Sarah C; Anderson, Judy B; Meldrum, Deirdre R; Parviz, Babak A

    2009-06-01

    We report a method for forming arrays of live single cells on a chip using polymer micro-traps made of SU8. We have studied the toxicity of the microfabricated structures and the associated environment for two cell lines. We also report a method for measuring the oxygen consumption rate of a single cell using optical interrogation of molecular oxygen sensors placed in micromachined micro-wells by temporarily sealing the cells in the micro-traps. The new techniques presented here add to the collection of tools available for performing "single-cell" biology. A single-cell self-assembly yield of 61% was achieved with oxygen draw down rates of 0.83, 0.82, and 0.71 fmol/minute on three isolated live A549 cells.

  3. Oxygen consumption during mineralization of organic compounds in water samples from a small sub-tropical reservoir (Brazil

    Directory of Open Access Journals (Sweden)

    Cunha-Santino Marcela Bianchessi da

    2003-01-01

    Full Text Available Assays were carried out to evaluate the oxygen consumption resulting from mineralization of different organic compounds: glucose, sucrose, starch, tannic acid, lysine and glycine. The compounds were added to 1 l of water sample from Monjolinho Reservoir. Dissolved oxygen and dissolved organic carbon were monitored during 20 days and the results were fitted to first order kinetics model. During the 20 days of experiments, the oxygen consumption varied from 4.5 mg.l-1 (tannic acid to 71.5 mg.l-1 (glucose. The highest deoxygenation rate (kD was observed for mineralization of tannic acid (0.321 day-1 followed by glycine, starch, lysine, sucrose and glucose (0.1004, 0.0504, 0.0486, 0.0251 and 0.0158 day-1, respectively. From theoretical calculations and oxygen and carbon concentrations we obtained the stoichiometry of the mineralization processes. Stoichiometric values varied from 0.17 (tannic acid to 2.55 (sucrose.

  4. Low energy consumption method for separating gaseous mixtures and in particular for medium purity oxygen production

    Science.gov (United States)

    Jujasz, Albert J.; Burkhart, James A.; Greenberg, Ralph

    1988-01-01

    A method for the separation of gaseous mixtures such as air and for producing medium purity oxygen, comprising compressing the gaseous mixture in a first compressor to about 3.9-4.1 atmospheres pressure, passing said compressed gaseous mixture in heat exchange relationship with sub-ambient temperature gaseous nitrogen, dividing the cooled, pressurized gaseous mixture into first and second streams, introducing the first stream into the high pressure chamber of a double rectification column, separating the gaseous mixture in the rectification column into a liquid oxygen-enriched stream and a gaseous nitrogen stream and supplying the gaseous nitrogen stream for cooling the compressed gaseous mixture, removing the liquid oxygen-enriched stream from the low pressure chamber of the rectification column and pumping the liquid, oxygen-enriched steam to a predetermined pressure, cooling the second stream, condensing the cooled second stream and evaporating the oxygen-enriched stream in an evaporator-condenser, delivering the condensed second stream to the high pressure chamber of the rectification column, and heating the oxygen-enriched stream and blending the oxygen-enriched stream with a compressed blend-air stream to the desired oxygen concentration.

  5. Myocardial Blood Volume Is Associated with Myocardial Oxygen Consumption: An Experimental Study with CMR in a Canine Model

    Science.gov (United States)

    McCommis, Kyle S.; Zhang, Haosen; Goldstein, Thomas A.; Misselwitz, Bernd; Abendschein, Dana R.; Gropler, Robert J.; Zheng, Jie

    2009-01-01

    OBJECTIVES To evaluate the feasibility of cardiovascular MR (CMR) to determine regional myocardial perfusion and O2 metabolism, and assess the role of myocardial blood volume (MBV) on oxygen supply. BACKGROUND Coronary artery disease presents as an imbalance of myocardial oxygen supply and demand. We have developed relevant CMR methods to determine the relationship of myocardial blood flow (MBF) and MBV to oxygen consumption (MVO2) during pharmacologic hyperemia. METHODS Twenty-one mongrel dogs were studied with varying stenosis severities imposed on the proximal left anterior descending (LAD) coronary artery. MBF and MBV were determined by CMR first-pass perfusion, while the oxygen extraction fraction (OEF) and MVO2 were determined by the myocardial Blood-Oxygen-Level-Dependent (BOLD) effect and Fick’s law, respectively. MR imaging was performed at rest, and during either dipyridamole-induced vasodilation or dobutamine-induced hyperemia. Regional differences in myocardial perfusion and oxygenation were then evaluated. RESULTS Dipyridamole and dobutamine both led to 145–200% increases in MBF and 50–80% increases in MBV in normal perfused myocardium. As expected, MVO2 increased more significantly with dobutamine (~175%) than dipyridamole (~40%). Coronary stenosis resulted in an attenuation of MBF, MBV, and MVO2 in both the LAD-subtended stenosis region and the left circumflex subtended remote region. Liner regression analysis showed that MBV reserve appears to be more correlated with MVO2 reserve during dobutamine stress than MBF reserve, particularly in the stenotic regions. Conversely, MBF reserve appears to be more correlated with MVO2 reserve during dipyridamole, although neither of these differences was significant. CONCLUSIONS Noninvasive evaluation of both myocardial perfusion and oxygenation by CMR facilitates direct monitoring of regional myocardial ischemia and provides a valuable tool for better understanding microvascular pathophysiology. These

  6. Changes in Whole-Body Oxygen Consumption and Skeletal Muscle Mitochondria During Linezolid-Induced Lactic Acidosis.

    Science.gov (United States)

    Protti, Alessandro; Ronchi, Dario; Bassi, Gabriele; Fortunato, Francesco; Bordoni, Andreina; Rizzuti, Tommaso; Fumagalli, Roberto

    2016-07-01

    To better clarify the pathogenesis of linezolid-induced lactic acidosis. Case report. ICU. A 64-year-old man who died with linezolid-induced lactic acidosis. Skeletal muscle was sampled at autopsy to study mitochondrial function. Lactic acidosis developed during continuous infusion of linezolid while oxygen consumption and oxygen extraction were diminishing from 172 to 52 mL/min/m and from 0.27 to 0.10, respectively. Activities of skeletal muscle respiratory chain complexes I, III, and IV, encoded by nuclear and mitochondrial DNA, were abnormally low, whereas activity of complex II, entirely encoded by nuclear DNA, was not. Protein studies confirmed stoichiometric imbalance between mitochondrial (cytochrome c oxidase subunits 1 and 2) and nuclear (succinate dehydrogenase A) DNA-encoded respiratory chain subunits. These findings were not explained by defects in mitochondrial DNA or transcription. There were no compensatory mitochondrial biogenesis (no induction of nuclear respiratory factor 1 and mitochondrial transcript factor A) or adaptive unfolded protein response (reduced concentration of heat shock proteins 60 and 70). Linezolid-induced lactic acidosis is associated with diminished global oxygen consumption and extraction. These changes reflect selective inhibition of mitochondrial protein synthesis (probably translation) with secondary mitonuclear imbalance. One novel aspect of linezolid toxicity that needs to be confirmed is blunting of reactive mitochondrial biogenesis and unfolded protein response.

  7. Effect of esmolol infusion on myocardial oxygen consumption during extubation and quality of recovery in elderly patients undergoing general anesthesia: randomized, double blinded, clinical trial

    Directory of Open Access Journals (Sweden)

    Sherif A. ELokda

    2015-04-01

    Conclusions: Esmolol is a safe, effective and well-tolerated drug that can be used in elderly patients undergoing general anesthesia to reduce the myocardial oxygen consumption and improve the quality of recovery.

  8. The effects of interval- vs. continuous exercise on excess post-exercise oxygen consumption and substrate oxidation rates in subjects with type 2 diabetes

    DEFF Research Database (Denmark)

    Karstoft, Kristian; Wallis, Gareth A.; Pedersen, Bente K.

    2016-01-01

    Background For unknown reasons, interval training often reduces body weight more than energy-expenditure matched continuous training. We compared the acute effects of time-duration and oxygen-consumption matched interval- vs. continuous exercise on excess post-exercise oxygen consumption (EPOC...... (MMTT, 450 kcal) was consumed by the subjects 45 min after completion of the intervention with blood samples taken regularly. Results Exercise interventions were successfully matched for total oxygen consumption (CW = 1641 ± 133 mL/min; IW = 1634 ± 126 mL/min, P > 0.05). EPOC was higher after IW (8......, free fatty acids and glycerol concentrations, and glycerol kinetics were increased comparably during and after IW and CW compared to CON. Conclusions Interval exercise results in greater EPOC than oxygen-consumption matched continuous exercise during a post-exercise MMTT in subjects with T2D, whereas...

  9. Local cerebral blood flow (1CBF) and oxygen consumption (1CMRO2) in evolving irreversible ischemic infarction: a study with positron tomography and oxygen-15

    International Nuclear Information System (INIS)

    Baron, J.C.; Rougemont, D.; Lebrun-Grandie, P.; Comar, D.; Bousser, M.G.; Bories, J.; Castaigne, P.; Cabanis, E.

    1982-09-01

    In 25 patients suffering from cerebral ischemia set up in the area of the internal carotid artery the local cerebral blood flow (lCBF) and local cerebral oxygen consumption (lCMRO 2 ) were measured by the method of continuous inhalation of oxygen 15-labelled gas combined with positron emission tomography. These two local parameters and their ratio, the local oxygen extraction rate (lO 2 E), were studied inside the brain region tending spontaneously towards ischemic necrosis, a zone defined by means of repeated tomodensitometric examinations. The essential facts observed are the variability of the lCBF and the lO 2 E values, from extremely low to extremely high, whereas the collapse of the lCMRO 2 is constant. Consequently this last parameter alone would be a good prognostic index, an lCMRO 2 decrease to a level below about 70% of the controlateral value indicating that the necrosis is spontaneously irreparable. These results are discussed in the light of published data

  10. Physical training in children with osteogenesis imperfecta.

    Science.gov (United States)

    Van Brussel, Marco; Takken, Tim; Uiterwaal, Cuno S P M; Pruijs, Hans J; Van der Net, Janjaap; Helders, Paul J M; Engelbert, Raoul H H

    2008-01-01

    To study the effects of a physical training program on exercise capacity, muscle force, and subjective fatigue levels in patients with mild to moderate forms of osteogenesis imperfecta (OI). Thirty-four children with OI type I or IV were randomly assigned to either a 12-week graded exercise program or care as usual for 3 months. Exercise capacity and muscle force were studied; subjective fatigue, perceived competence, and health-related quality of life were secondary outcomes. All outcomes were measured at baseline (T = 0), after intervention (T = 1), and after 6 and 9 months (T = 2 and T = 3, respectively). After intervention (T = 1), peak oxygen consumption (VO2peak), relative VO2peak (VO2peak/kg), maximal working capacity (Wmax), and muscle force were significantly improved (17%, 18%, 10%, and 12%, respectively) compared with control values. Subjective fatigue decreased borderline statistically significantly. Follow-up at T = 2 showed a significant decrease of the improvements measured at T = 1 of VO2peak, but VO2peak/kg, Wmax, and subjective fatigue showed no significant difference. At T = 3, we found a further decrease of the gained improvements. A supervised training program can improve aerobic capacity and muscle force and reduces levels of subjective fatigue in children with OI type I and IV in a safe and effective manner.

  11. Aerobic fitness related to cardiovascular risk factors in young children

    DEFF Research Database (Denmark)

    Dencker, Magnus; Thorsson, Ola; Karlsson, Magnus K

    2012-01-01

    Low aerobic fitness (maximum oxygen uptake (VO(2PEAK))) is predictive for poor health in adults. In a cross-sectional study, we assessed if VO(2PEAK) is related to a composite risk factor score for cardiovascular disease (CVD) in 243 children (136 boys and 107 girls) aged 8 to 11 years. VO(2PEAK...

  12. Step Test: a method for evaluating maximum oxygen consumption to determine the ability kind of work among students of medical emergencies.

    Science.gov (United States)

    Heydari, Payam; Varmazyar, Sakineh; Nikpey, Ahmad; Variani, Ali Safari; Jafarvand, Mojtaba

    2017-03-01

    Maximum oxygen consumption shows the maximum oxygen rate of muscle oxygenation that is acceptable in many cases, to measure the fitness between person and the desired job. Given that medical emergencies are important, and difficult jobs in emergency situations require people with high physical ability and readiness for the job, the aim of this study was to evaluate the maximum oxygen consumption, to determine the ability of work type among students of medical emergencies in Qazvin in 2016. This study was a descriptive - analytical, and in cross-sectional type conducted among 36 volunteer students of medical emergencies in Qazvin in 2016. After necessary coordination for the implementation of the study, participants completed health questionnaires and demographic characteristics and then the participants were evaluated with step tests of American College of Sport Medicine (ACSM). Data analysis was done by SPSS version 18 and U-Mann-Whitney tests, Kruskal-Wallis and Pearson correlation coefficient. Average of maximum oxygen consumption of the participants was estimated 3.15±0.50 liters per minute. 91.7% of medical emergencies students were selected as appropriate in terms of maximum oxygen consumption and thus had the ability to do heavy and too heavy work. Average of maximum oxygen consumption evaluated by the U-Mann-Whitney test and Kruskal-Wallis, had significant relationship with age (p<0.05) and weight groups (p<0.001). There was a significant positive correlation between maximum oxygen consumption with weight and body mass index (p<0.001). The results of this study showed that demographic variables of weight and body mass index are the factors influencing the determination of maximum oxygen consumption, as most of the students had the ability to do heavy, and too heavy work. Therefore, people with ability to do average work are not suitable for medical emergency tasks.

  13. Validation and Refinement of Prediction Models to Estimate Exercise Capacity in Cancer Survivors Using the Steep Ramp Test

    NARCIS (Netherlands)

    Stuiver, Martijn M.; Kampshoff, Caroline S.; Persoon, Saskia; Groen, Wim; van Mechelen, Willem; Chinapaw, Mai J. M.; Brug, Johannes; Nollet, Frans; Kersten, Marie-José; Schep, Goof; Buffart, Laurien M.

    2017-01-01

    Objective: To further test the validity and clinical usefulness of the steep ramp test (SRT) in estimating exercise tolerance in cancer survivors by external validation and extension of previously published prediction models for peak oxygen consumption (Vo2(peak)) and peak power output (W-peak).&

  14. Relationship between level of forage intake, blood flow and oxygen consumption by splanchnic tissues of sheep fed a tropical grass forage.

    Science.gov (United States)

    Hentz, F; Kozloski, G V; Zeni, D; Brun, M V; Stefanello, S

    2017-02-01

    Four Polwarth castrated male sheep (42 ± 4.4 kg live weight (LW) surgically implanted with chronic indwelling catheters into the mesenteric, portal and hepatic veins, housed in metabolism cages and offered Cynodon sp. hay at rates (g of dry matter (DM)/kg LW) of 7, 14, 21 or ad libitum, were used in a 4 × 4 Latin square experiment to evaluate the effect of the level of forage intake on blood flow and oxygen consumption by the portal-drained viscera (PDV), liver and total splanchnic tissues (ST). The portal blood flow and the oxygen consumption by PDV linearly increased at increased organic matter (OM) intake. No effect of level of OM intake was obtained for the hepatic artery blood flow and oxygen consumption by liver. As a consequence, the level of OM intake only tended to directly affect hepatic blood flow and oxygen consumption by total ST. Oxygen consumption was linearly and positively related to blood flow across PDV, liver and total ST. The heat production by PDV and total ST, as proportion of metabolizable energy (ME) intake, decreased curvilinearly at increased ME intake. In conclusion, the oxygen consumption by PDV, but not by liver, was directly related to the level of forage intake by sheep. Moreover, when ingested at levels below maintenance, most of ME was spent as heat produced by ST. Journal of Animal Physiology and Animal Nutrition © 2016 Blackwell Verlag GmbH.

  15. The impact of acute bouts of interval and continuous walking on energy-intake and appetite regulation in subjects with type 2 diabetes

    DEFF Research Database (Denmark)

    Müller, Ida A; Wedell-Neergaard, Anne-Sophie; Solomon, Thomas P J

    2017-01-01

    In healthy subjects, it has been suggested that exercise may acutely suppress energy-intake and appetite, with peak intensity being an important determinant for this effect. In subjects with type 2 diabetes (T2D), the effect of exercise on appetite-related variables is, however, virtually unknown....... We aimed to assess the effects of two exercise interventions, differing with regards to peak intensity, on energy-intake, satiety and appetite-related hormones in subjects with T2D. Thirteen subjects with T2D completed three 60-min interventions with continuous measurement of oxygen consumption...... in a randomized and counterbalanced order: (1) Control, (2) Continuous walking (CW; intended 73% of VO2peak), (3) Interval-walking (IW; repeated cycles of 3 min slow [54% of VO2peak] and 3 min fast walking [89% of VO2peak]). Forty-five minutes after completion of the intervention, a 3-h liquid mixed meal...

  16. Noninvasive in vivo optical characterization of blood flow and oxygen consumption in the superficial plexus of skin

    Science.gov (United States)

    Liasi, Faezeh Talebi; Samatham, Ravikant; Jacques, Steven L.

    2017-11-01

    Assessing the metabolic activity of a tissue, whether normal, damaged, aged, or pathologic, is useful for diagnosis and evaluating the effects of drugs. This report describes a handheld optical fiber probe that contacts the skin, applies pressure to blanch the superficial vascular plexus of the skin, then releases the pressure to allow refill of the plexus. The optical probe uses white light spectroscopy to record the time dynamics of blanching and refilling. The magnitude and dynamics of changes in blood content and hemoglobin oxygen saturation yield an estimate of the oxygen consumption rate (OCR) in units of attomoles per cell per second. The average value of OCR on nine forearm sites on five subjects was 10±5 (amol/cell/s). This low-cost, portable, rapid, noninvasive optical probe can characterize the OCR of a skin site to assess the metabolic activity of the epidermis or a superficial lesion.

  17. Impact of Increasing Levels of Oxygen Consumption on the Evolution of Color, Phenolic, and Volatile Compounds of Nebbiolo Wines

    Directory of Open Access Journals (Sweden)

    Maurizio Petrozziello

    2018-04-01

    Full Text Available Since the end of the last century, many works have been carried out to verify the effect of controlled oxygen intake on the chemical and organoleptic characteristics of red wines. In spite of the large number of studies on this subject, oxygen remains a cutting-edge research topic in oenology. Oxygen consumption leads to complex and not univocal changes in wine composition, sometimes positive such as color stabilization, softening of mouthfeel, increase of aroma complexity. However, the variability of these effects, which depend both on the oxygenation conditions and the composition of the wine, require more efforts in this research field to effectively manage wine oxygen exposure. The present study is focused on the evolution of the chemical composition of four different Nebbiolo wines, each of them added with 4 different doses of oxygen (7, 14, 21, and 28 mg/L total intake during the first month of storage. In this perspective, the evolution over time of wine color and polyphenols was studied. Acetaldehyde, glyceraldehyde and glyoxylic acid were quantified by HPLC. These compounds can play a role in wine aging creating condensed colored and stable products involving anthocyanins with or without tannins. Moreover, some volatile aldehydes correlated with oxidized olfactory notes, including methional and (E-2-alkenals, have been quantified by GC-MS. Overall, during storage a decrease of color intensity, total and free anthocyanins and an increase in polymeric pigments (in particular the contribution to the red color of pigments not-bleachable by SO2 or dTAT% and some minor aldehydes was observed. Nevertheless, the differences in color parameters between the samples with different doses of oxygen were modest. These evidences were in contrast with an evident and detectable increase of free acetaldehyde content at increasing doses of oxygen measured after 60 days of storage. The effect of oxygen on color and production of SO2 non-bleachable pigments

  18. Impact of Increasing Levels of Oxygen Consumption on the Evolution of Color, Phenolic, and Volatile Compounds of Nebbiolo Wines.

    Science.gov (United States)

    Petrozziello, Maurizio; Torchio, Fabrizio; Piano, Federico; Giacosa, Simone; Ugliano, Maurizio; Bosso, Antonella; Rolle, Luca

    2018-01-01

    Since the end of the last century, many works have been carried out to verify the effect of controlled oxygen intake on the chemical and organoleptic characteristics of red wines. In spite of the large number of studies on this subject, oxygen remains a cutting-edge research topic in oenology. Oxygen consumption leads to complex and not univocal changes in wine composition, sometimes positive such as color stabilization, softening of mouthfeel, increase of aroma complexity. However, the variability of these effects, which depend both on the oxygenation conditions and the composition of the wine, require more efforts in this research field to effectively manage wine oxygen exposure. The present study is focused on the evolution of the chemical composition of four different Nebbiolo wines, each of them added with 4 different doses of oxygen (7, 14, 21, and 28 mg/L total intake) during the first month of storage. In this perspective, the evolution over time of wine color and polyphenols was studied. Acetaldehyde, glyceraldehyde and glyoxylic acid were quantified by HPLC. These compounds can play a role in wine aging creating condensed colored and stable products involving anthocyanins with or without tannins. Moreover, some volatile aldehydes correlated with oxidized olfactory notes, including methional and (E)-2-alkenals, have been quantified by GC-MS. Overall, during storage a decrease of color intensity, total and free anthocyanins and an increase in polymeric pigments (in particular the contribution to the red color of pigments not-bleachable by SO 2 or dTAT%) and some minor aldehydes was observed. Nevertheless, the differences in color parameters between the samples with different doses of oxygen were modest. These evidences were in contrast with an evident and detectable increase of free acetaldehyde content at increasing doses of oxygen measured after 60 days of storage. The effect of oxygen on color and production of SO 2 non-bleachable pigments during aging

  19. Impact of Increasing Levels of Oxygen Consumption on the Evolution of Color, Phenolic, and Volatile Compounds of Nebbiolo Wines

    Science.gov (United States)

    Petrozziello, Maurizio; Torchio, Fabrizio; Piano, Federico; Giacosa, Simone; Ugliano, Maurizio; Bosso, Antonella; Rolle, Luca

    2018-01-01

    Since the end of the last century, many works have been carried out to verify the effect of controlled oxygen intake on the chemical and organoleptic characteristics of red wines. In spite of the large number of studies on this subject, oxygen remains a cutting-edge research topic in oenology. Oxygen consumption leads to complex and not univocal changes in wine composition, sometimes positive such as color stabilization, softening of mouthfeel, increase of aroma complexity. However, the variability of these effects, which depend both on the oxygenation conditions and the composition of the wine, require more efforts in this research field to effectively manage wine oxygen exposure. The present study is focused on the evolution of the chemical composition of four different Nebbiolo wines, each of them added with 4 different doses of oxygen (7, 14, 21, and 28 mg/L total intake) during the first month of storage. In this perspective, the evolution over time of wine color and polyphenols was studied. Acetaldehyde, glyceraldehyde and glyoxylic acid were quantified by HPLC. These compounds can play a role in wine aging creating condensed colored and stable products involving anthocyanins with or without tannins. Moreover, some volatile aldehydes correlated with oxidized olfactory notes, including methional and (E)-2-alkenals, have been quantified by GC-MS. Overall, during storage a decrease of color intensity, total and free anthocyanins and an increase in polymeric pigments (in particular the contribution to the red color of pigments not-bleachable by SO2 or dTAT%) and some minor aldehydes was observed. Nevertheless, the differences in color parameters between the samples with different doses of oxygen were modest. These evidences were in contrast with an evident and detectable increase of free acetaldehyde content at increasing doses of oxygen measured after 60 days of storage. The effect of oxygen on color and production of SO2 non-bleachable pigments during aging

  20. Effects of Cortical Spreading Depression on Synaptic Activity, Blood Flow and Oxygen Consumption in Rat Cerebral Cortex

    DEFF Research Database (Denmark)

    Hansen, Henning Piilgaard

    2010-01-01

    As the title of this thesis indicates I have during my PhD studied the effects of cortical spreading depression (CSD) on synaptic activity, blood flow and oxygen consumption in rat cerebral cortex. This was performed in vivo using an open cranial window approach in anesthetized rats. I applied...... parameters of the whisker/infraorbital nerve etwork (IO) targeting the same cortical area. We tested the hypothesis that the relation between increases in CBF and CMRO2 evoked by stimulation and synaptic activity differed for the two activated networks and that activation of two distinct networks activate...

  1. Low Cerebral Oxygen Consumption and Blood Flow in Patients With Cirrhosis and an Acute Episode of Hepatic Encephalopathy

    DEFF Research Database (Denmark)

    Iversen, Peter; Bak, Lasse Kristoffer; Waagepetersen, Helle Sønderby

    2009-01-01

    (15)O-water PET in 6 patients with liver cirrhosis and an acute episode of overt HE, 6 cirrhotic patients without HE, and 7 healthy subjects. RESULTS: Neither whole-brain CMRO(2) nor CBF differed significantly between cirrhotic patients without HE and healthy subjects, but were both significantly...... that the reductions in CMRO(2) and CBF in patients with HE were essentially generalized throughout the brain. CONCLUSIONS: The observations imply that reduced cerebral oxygen consumption and blood flow in cirrhotic patients with an acute episode of overt HE are associated with HE and not cirrhosis as such...

  2. Kinetics of oxygen consumption after a single flash of light in photoreceptors of the drone (Apis mellifera)

    OpenAIRE

    1982-01-01

    The time course of the rate of oxygen consumption (QO2) after a single flash of light has been measured in 300-micrometers slices of drone retina at 22 degrees C. To measure delta QO2(t), the change in QO2 from its level in darkness, the transients of the partial pressure of O2 (PO2) were recorded with O2 microelectrodes simultaneously in two sites in the slice and delta QO2 was calculated by a computer using Fourier transforms. After a 40-ms flash of intense light, delta QO2, reached a peak ...

  3. Effects of Low-Permeability Layers in the Hyporheic Zone on Oxygen Consumption Under Losing and Gaining Groundwater Flow Conditions

    Science.gov (United States)

    Arnon, S.; Krause, S.; Gomez-Velez, J. D.; De Falco, N.

    2017-12-01

    Recent studies at the watershed scale have demonstrated the dominant role that river bedforms play in driving hyporheic exchange and constraining biogeochemical processes along river corridors. At the reach and bedform scales, modeling studies have shown that sediment heterogeneity significantly modifies hyporheic flow patterns within bedforms, resulting in spatially heterogeneous biogeochemical processes. In this work, we summarize a series of flume experiments to evaluate the effect that low-permeability layers, representative of structural heterogeneity, have on hyporheic exchange and oxygen consumption in sandy streambeds. In this case, we systematically changed the geometry of the heterogeneities, the surface channel flow driving the exchange, and groundwater fluxes (gaining/losing) modulating the exchange. The flume was packed with natural sediments, which were amended with compost to minimize carbon limitations. Structural heterogeneities were represented by continuous and discontinuous layers of clay material. Flow patterns were studied using dye imaging through the side walls. Oxygen distribution in the streambed was measured using planar optodes. The experimental observations revealed that the clay layer had a significant effect on flow patterns and oxygen distribution in the streambed under neutral and losing conditions. Under gaining conditions, the aerobic zone was limited to the upper sections of the bedform and thus was less influenced by the clay layers that were located at a depth of 1-3 cm below the water-sediment interface. We are currently analyzing the results with a numerical flow and transport model to quantify the reactions rates under the different flow conditions and spatial sediment structures. Our preliminary results enable us to show the importance of the coupling between flow conditions, local heterogeneity within the streambed and oxygen consumption along bed forms and are expected to improve our ability to model the effect of stream

  4. The effect of exercise intensity and excess postexercise oxygen consumption on postprandial blood lipids in physically inactive men.

    Science.gov (United States)

    Littlefield, Laurel A; Papadakis, Zacharias; Rogers, Katie M; Moncada-Jiménez, José; Taylor, J Kyle; Grandjean, Peter W

    2017-09-01

    Reductions in postprandial lipemia have been observed following aerobic exercise of sufficient energy expenditure. Increased excess postexercise oxygen consumption (EPOC) has been documented when comparing high- versus low-intensity exercise. The contribution of EPOC energy expenditure to alterations in postprandial lipemia has not been determined. The purpose of this study was to evaluate the effects of low- and high-intensity exercise on postprandial lipemia in healthy, sedentary, overweight and obese men (age, 43 ± 10 years; peak oxygen consumption, 31.1 ± 7.5 mL·kg -1 ·min -1 ; body mass index, 31.8 ± 4.5 kg/m 2 ) and to determine the contribution of EPOC to reductions in postprandial lipemia. Participants completed 4 conditions: nonexercise control, low-intensity exercise at 40%-50% oxygen uptake reserve (LI), high-intensity exercise at 70%-80% oxygen uptake reserve (HI), and HI plus EPOC re-feeding (HI+EERM), where the difference in EPOC energy expenditure between LI and HI was re-fed in the form of a sports nutrition bar (Premier Nutrition Corp., Emeryville, Calif., USA). Two hours following exercise participants ingested a high-fat (1010 kcals, 99 g sat fat) test meal. Blood samples were obtained before exercise, before the test meal, and at 2, 4, and 6 h postprandially. Triglyceride incremental area under the curve was significantly reduced following LI, HI, and HI+EERM when compared with nonexercise control (p exercise conditions (p > 0.05). In conclusions, prior LI and HI exercise equally attenuated postprandial triglyceride responses to the test meal. The extra energy expended during EPOC does not contribute significantly to exercise energy expenditure or to reductions in postprandial lipemia in overweight men.

  5. Direct measurements of the light dependence of gross photosynthesis and oxygen consumption in the ocean

    Science.gov (United States)

    Bailleul, B.; Park, J.; Brown, C. M.; Bidle, K. D.; Lee, S.; Falkowski, P. G.

    2016-02-01

    For decades, a lack of understanding of how respiration is influenced by light has been stymying our ability to quantitatively analyze how phytoplankton allocate carbon in situ and the biological mechanisms that participate to the fate of blooms. Using membrane inlet mass spectrometry (MIMS), the light dependencies of gross photosynthesis and oxygen uptake rates were measured during the bloom demises of two prymnesiophytes, in two open ocean regions. In the North Atlantic, dominated by Emiliania huxleyi, respiration was independent of irradiance and was higher than the gross photosynthetic rate at all irradiances. In the Amundsen Sea (Antarctica), dominated by Phaeocystis antarctica, the situation was very different. Dark respiration was one order of magnitude lower than the maximal gross photosynthetic rate. ut the oxygen uptake rate increased by 10 fold at surface irradiances, where it becomes higher than gross photosynthesis. Our results suggest that the light dependence of oxygen uptake in P. antarctica has two sources: one is independent of photosynthesis, and is possibly associated with the photo-reduction of O2 mediated by dissolved organic matter; the second reflects the activity of an oxidase fueled in the light with photosynthetic electron flow. Interestingly, these dramatic light-dependent changes in oxygen uptake were not reproduced in nutrient-replete P. antarctica cultures, in the laboratory. Our measurements highlight the importance of improving our understanding of oxygen consuming reactions in the euphotic zone, which is critical to investigating the physiology of phytoplankton and tracing the fate of phytoplankton blooms.

  6. Effective oxygen-consumption rates in fermentation broths with filamentous organisms

    Energy Technology Data Exchange (ETDEWEB)

    Reuss, M; Bajpai, R K; Berke, W

    1982-01-01

    The concept of coupling molecular diffusion and reaction has been applied in the past to various biological systems with clearly defined geometrical properties like pellets and immobilised enzymes/microorganisms. This paper investigates the use of the same principle to characterise the diffusional limitation in suspensions of filamentous microorganisms. Experimental results of oxygen-uptake measurements from Aspergillus niger fermentations in a 50 cu.dm turbine-agitated fermentor are presented with theoretical predictions of coupled diffusion and oxygen kinetics. Results are discussed on the basis of turbulence theory so that the mycelial broth can be structured in hypothetical spherical elements. Consideration of local energy-dissipation rates in the impeller region provides reasonable explanation of the strong influence of the impeller/tank diameter ratio on the effective oxygen-uptake rate at a given power input. (Refs. 18).

  7. Oxygen Consumption and Acoustic Activity of Adult Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae: Bruchinae) during Hermetic Storage.

    Science.gov (United States)

    Njoroge, Anastasia W; Mankin, Richard W; Smith, Bradley W; Baributsa, Dieudonne

    2018-04-20

    Acoustic monitoring was applied to consider hermetic exposure durations and oxygen levels required to stop adult Callosobruchus maculatus activity and economic damage on cowpea. A 15-d study was conducted with six treatments of 25, 50, and 100 C. maculatus adults in 500 and 1000 mL jars using acoustic probes inserted through stoppers sealing the jars. Acoustic activity as a result of locomotion, mating, and egg-laying was measured by identifying sound impulses with frequency spectra representative of known insect sounds, and counting trains (bursts) of impulses separated by intervals of <200 ms, that typically are produced only by insects. By the end of the first week of storage in all treatments, oxygen levels declined to levels below 4%, which has been demonstrated to cause mortality in previous studies. Concomitantly, insect sound burst rates dropped below an acoustic detection threshold of 0.02 bursts s −1 , indicating that the insects had ceased feeding. Statistically significant relationships were obtained between two different measures of the acoustic activity and the residual oxygen level. Based on the experimental results, a simple equation can be used to estimate the time needed for oxygen to decline to levels that limit insect feeding damage and thus grain losses in hermetic storage containers of different insect population levels and various volumes.

  8. Using carbon emissions and oxygen consumption to estimate energetics parameters of cattle consuming forages

    Science.gov (United States)

    To evaluate newer indirect calorimetry system to quantify energetic parameters, 8 cross-bred beef steers (initial BW = 241 ± 4.10 kg) were used in a 77-d experiment to examine energetics parameters calculated from carbon dioxide (CO2), methane (CH4), and oxygen (O2) fluxes. Steers were individually ...

  9. Sodium cyanide induced alteration in the whole animal oxygen consumption and behavioural pattern of freshwater fish Labeo rohita.

    Science.gov (United States)

    David, Muniswamy; Sangeetha, Jeyabalan; Harish, Etigemane R

    2015-03-01

    Sodium cyanide is a common environmental pollutant which is mainly used in many industries such as mining, electroplating, steel manufacturing, pharmaceutical production and other specialized applications including dyes and agricultural products. It enters aquatic environment through effluents from these industries. Static renewal bioassay test has been conducted to determine LC, of sodium cyanide on indigenous freshwater carp, Labeo rohita. The behavioural pattern and oxygen consumption were observed in fish at both lethal and sub lethal concentrations. Labeo rohita in toxic media exhibited irregular and erratic swimming movements, hyper excitability, loss of equilibrium and shrinking to the bottom, which may be due to inhibition of cytochrome C oxidase activity and decreased blood pH. The combination of cytotoxic hypoxia with lactate acidosis depresses the central nervous system resulting in respiratory arrest and death. Decrease in oxygen consumption was observed at both lethal and sub lethal concentrations of sodium cyanide. Mortality was insignificant at sub lethal concentration test when fishes were found under stress. Consequence of impaired oxidative metabolism and elevated physiological response by fish against sodium cyanide stress showed alteration in respiratory rate.

  10. Effects of a whole-body spandex garment on rectal temperature and oxygen consumption in healthy dogs.

    Science.gov (United States)

    Reimer, S Brent; Schulz, Kurt S; Mason, David R; Jones, James H

    2004-01-01

    To determine whether a full-body spandex garment would alter rectal temperatures of healthy dogs at rest in cool and warm environments. Prospective study. 10 healthy dogs. Each dog was evaluated at a low (20 degrees to 25 degrees C [68 degrees to 77 degrees F]) or high (30 degrees to 35 degrees C [86 degrees to 95 degrees F]) ambient temperature while wearing or not wearing a commercially available whole-body spandex garment designed for dogs. Oxygen consumption was measured by placing dogs in a flow-through indirect calorimeter for 90 to 120 minutes. Rectal temperature was measured before dogs were placed in the calorimeter and after they were removed. Rectal temperature increased significantly more at the higher ambient temperature than at the lower temperature and when dogs were not wearing the garment than when they were wearing it. The specific rate of oxygen consumption was significantly higher at the lower ambient temperature than at the higher temperature. Results suggest that wearing a snug spandex body garment does not increase the possibility that dogs will overheat while in moderate ambient temperatures. Instead, wearing such a garment may enable dogs to better maintain body temperature during moderate heat loading. These results suggest that such garments might be used for purposes such as wound or suture protection without causing dogs to overheat.

  11. Measurement of Diaphragmatic Blood Flow and Oxygen Consumption in the Dog by the Kety-Schmidt Technique

    Science.gov (United States)

    Rochester, Dudley F.

    1974-01-01

    To assess energy expenditure of the diaphragm directly, a method was devised for percutaneous catheterization of the left inferior phrenic vein in dogs. Necropsy studies, including retrograde injection of india ink and measurement of radioactivity in diaphragmatic muscle strips, suggested that the territory drained by the inferior phrenic vein was uniformly perfused, and that there were no major anastomoses between this bed and adjacent ones. Diaphragmatic blood flow (˙Q di) was calculated from the integrated diaphragmatic arteriovenous difference of 85Kr by the Kety-Schmidt technique. Diaphragmatic oxygen consumption (˙Vo2 di) was determined as the product of ˙Q di and the diaphragmatic arteriovenous oxygen content difference [(A-V)O2 di]. When lightly anesthetized dogs breathed quietly, ˙Q di was 22±SD 6 ml/min/100 g, (A-V)O2 di was 6.1±SD 2.5 ml/100 ml, and ˙VO2 di averaged 1.2±SD 0.3 ml/min/100 g. This represented 1.0±SD 0.2% of total body oxygen consumption. ˙VO2 di remained relatively constant during quiet breathing, whereas ˙Q di varied directly with cardiac output and reciprocally with (A-V)O2 di. The oxygen consumption of the noncontracting diaphragm was 60±SD 20% of the level measured during quiet breathing. The energy expended by the diaphragm to support simple hyperventilation was small. A 100% increase in minute ventilation, induced by inhalation of 5% CO2 in 21% or 14% O2, increased ˙Q di 13%, (A-V)O2 di 19%, and ˙VO2 di 40%. The diaphragm consumed 0.13±SD 0.09 ml O2 for each additional liter of ventilation. In four dogs, pneumonia appeared to increase ˙VO2 both by increasing minute ventilation and by increasing the energy cost per liter of ventilation. PMID:4825221

  12. Oxygen consumption of a pneumatically controlled ventilator in a field anesthesia machine.

    Science.gov (United States)

    Szpisjak, Dale F; Javernick, Elizabeth N; Kyle, Richard R; Austin, Paul N

    2008-12-01

    Field anesthesia machines (FAM) have been developed for remote locations where reliable supplies of compressed medical gases or electricity may be absent. In place of electricity, pneumatically controlled ventilators use compressed gas to power timing circuitry and actuate valves. We sought to determine the total O(2) consumption and ventilator gas consumption (drive gas [DG] plus pneumatic control [PC] gas) of a FAM's pneumatically controlled ventilator in mechanical models of high (HC) and low (LC) total thoracic compliance. The amount of total O(2) consumed by the Magellan-2200 (Oceanic Medical Products, Atchison, KS) FAM with pneumatically controlled ventilator was calculated using the ideal gas law and the measured mass of O(2) consumed from E cylinders. DG to the bellows canister assembly was measured with the Wright Respirometer Mk 8 (Ferraris Respiratory Europe, Hertford, UK). PC gas consumption was calculated by subtracting DG and fresh gas flow (FGF) from the total O(2) consumed from the E cylinder. The delivered tidal volume (V(T)) was measured with a pneumotach (Hans Rudolph, KS City, MO). Three different V(T) were tested (500, 750, and 1000 mL) with two lung models (HC and LC) using the Vent Aid Training Test Lung (MI Instruments, Grand Rapids, MI). Respiratory variables included an I:E of 1:2, FGF of 1 L/min, and respiratory rate of 10 breaths/min. Total O(2) consumption was directly proportional to V(T) and inversely proportional to compliance. The smallest total O(2) consumption rate (including FGF) was 9.3 +/- 0.4 L/min in the HC-500 model and the largest was 15.9 +/- 0.5 L/min in the LC-1000 model (P < 0.001). The mean PC circuitry consumption was 3.9 +/- 0.24 L/min or 390 mL +/- 24 mL/breath. To prepare for loss of central DG supply, patient safety will be improved by estimating cylinder duration for low total thoracic compliance. Using data from the smaller compliance and greatest V(T) model (LC-1000), a full O(2) E cylinder would be depleted in

  13. Ketosis After Cardiopulmonary Bypass in Children Is Associated With an Inadequate Balance Between Oxygen Transport and Consumption.

    Science.gov (United States)

    Klee, Philippe; Arni, Delphine; Saudan, Sonja; Schwitzgebel, Valérie M; Sharma, Ruchika; Karam, Oliver; Rimensberger, Peter C

    2016-09-01

    Hyperglycemia after cardiac surgery and cardiopulmonary bypass in children has been associated with worse outcome; however, causality has never been proven. Furthermore, the benefit of tight glycemic control is inconsistent. The purpose of this study was to describe the metabolic constellation of children before, during, and after cardiopulmonary bypass, in order to identify a subset of patients that might benefit from insulin treatment. Prospective observational study, in which insulin treatment was initiated when postoperative blood glucose levels were more than 12 mmol/L (216 mg/dL). Tertiary PICU. Ninety-six patients 6 months to 16 years old undergoing cardiac surgery with cardiopulmonary bypass. None. Metabolic tests were performed before anesthesia, at the end of cardiopulmonary bypass, at PICU admission, and 4 and 12 hours after PICU admission, as well as 4 hours after initiation of insulin treatment. Ketosis was present in 17.9% patients at the end of cardiopulmonary bypass and in 31.2% at PICU admission. Young age was an independent risk factor for this condition. Ketosis at PICU admission was an independent risk factor for an increased difference between arterial and venous oxygen saturation. Four hours after admission (p = 0.05). Insulin corrected ketosis within 4 hours. In this study, we found a high prevalence of ketosis at PICU admission, especially in young children. This was independently associated with an imbalance between oxygen transport and consumption and was corrected by insulin. These results set the basis for future randomized controlled trials, to test whether this subgroup of patients might benefit from increased glucose intake and insulin during surgery to avoid ketosis, as improving oxygen transport and consumption might improve patient outcome.

  14. Persistent increase in oxygen consumption and impaired neurovascular coupling after spreading depression in rat neocortex

    DEFF Research Database (Denmark)

    Hansen, Henning Piilgaard; Lauritzen, Martin

    2009-01-01

    trauma. Here we tested the hypothesis that single episodes of CSD induced acute hypoxia, and prolonged impairment of neurovascular and neurometabolic coupling. Cortical spreading depression was induced in rat frontal cortex, whereas cortical electrical activity and local field potentials (LFPs) were......Cortical spreading depression (CSD) is associated with a dramatic failure of brain ion homeostasis and increased energy metabolism. There is strong clinical and experimental evidence to suggest that CSD is the mechanism of migraine, and involved in progressive neuronal injury in stroke and head...... recorded by glass microelectrodes, cerebral blood flow (CBF) by laser-Doppler flowmetry, and tissue oxygen tension (tpO(2)) with polarographic microelectrodes. Cortical spreading depression increased cerebral metabolic rate of oxygen (CMRO(2)) by 71%+/-6.7% and CBF by 238%+/-48.1% for 1 to 2 mins...

  15. Improving the Accuracy of Predicting Maximal Oxygen Consumption (VO2pk)

    Science.gov (United States)

    Downs, Meghan E.; Lee, Stuart M. C.; Ploutz-Snyder, Lori; Feiveson, Alan

    2016-01-01

    Maximal oxygen (VO2pk) is the maximum amount of oxygen that the body can use during intense exercise and is used for benchmarking endurance exercise capacity. The most accurate method to determineVO2pk requires continuous measurements of ventilation and gas exchange during an exercise test to maximal effort, which necessitates expensive equipment, a trained staff, and time to set-up the equipment. For astronauts, accurate VO2pk measures are important to assess mission critical task performance capabilities and to prescribe exercise intensities to optimize performance. Currently, astronauts perform submaximal exercise tests during flight to predict VO2pk; however, while submaximal VO2pk prediction equations provide reliable estimates of mean VO2pk for populations, they can be unacceptably inaccurate for a given individual. The error in current predictions and logistical limitations of measuring VO2pk, particularly during spaceflight, highlights the need for improved estimation methods.

  16. Method for the determination of oxygen consumption rates and diffusion coefficients in multicellular spheroids

    OpenAIRE

    Mueller-Klieser, W.

    1984-01-01

    A method has been developed for the quantitative evaluation of oxygen tension (PO2) distributions in multicellular spheroids measured with O2-sensitive microelectrodes. The experimental data showed that multicellular tumor spheroids in stirred growth media were characterized by a diffusion-depleted zone surrounding the spheroids. This zone was elicited by an unstirred layer of medium next to the spheroid leading to a continuous decrease in the PO2 values from the bulk medium towards the spher...

  17. The effects of lead, water hardness and pH on oxygen consumption ...

    African Journals Online (AJOL)

    Closed system respirometry was performed on captive juvenile Tilapia sparrmanii exposed for 96 hours to a range of Pb-acetate concentrations in hard and soft water to determine the effect of Pb in relation to water hardness and pH. For hard and soft water with a pH above 7.51 no change in the resting specific oxygen ...

  18. Simultaneously Occurring Elevated Metabolic States Expose Constraints in Maximal Levels of Oxygen Consumption in the Oviparous Snake Lamprophis fuliginosus.

    Science.gov (United States)

    Jackson, Alexander Garrett Schavran; Leu, Szu-Yun; Hicks, James W

    African house snakes (Lamprophis fuliginosus) were used to compare the metabolic increments associated with reproduction, digestion, and activity both individually and when combined simultaneously. Rates of oxygen consumption ([Formula: see text]) and carbon dioxide production ([Formula: see text]) were measured in adult female (nonreproductive and reproductive) and adult male snakes during rest, digestion, activity while fasting, and postprandial activity. We also compared the endurance time (i.e., time to exhaustion) during activity while fasting and postprandial activity in males and females. For nonreproductive females and males, our results indicate that the metabolic increments of digestion (∼3-6-fold) and activity while fasting (∼6-10-fold) did not interact in an additive fashion; instead, the aerobic scope associated with postprandial activity was 40%-50% lower, and animals reached exhaustion up to 11 min sooner. During reproduction, there was no change in digestive [Formula: see text], but aerobic scope for activity while fasting was 30% lower than nonreproductive values. The prioritization pattern of oxygen delivery exhibited by L. fuliginosus during postprandial activity (in both males and females) and for activity while fasting (in reproductive females) was more constrained than predicted (i.e., instead of unchanged [Formula: see text], peak values were 30%-40% lower). Overall, our results indicate that L. fuliginosus's cardiopulmonary system's capacity for oxygen delivery was not sufficient to maintain the metabolic increments associated with reproduction, digestion, and activity simultaneously without limiting aerobic scope and/or activity performance.

  19. CELL RESPIRATION STUDIES : II. A COMPARATIVE STUDY OF THE OXYGEN CONSUMPTION OF BLOOD FROM NORMAL INDIVIDUALS AND PATIENTS WITH INCREASED LEUCOCYTE COUNTS (SEPSIS; CHRONIC MYELOGENOUS LEUCEMIA).

    Science.gov (United States)

    Daland, G A; Isaacs, R

    1927-06-30

    1. The oxygen consumption of blood of normal individuals, when the hemoglobin is saturated with oxygen, is practically zero within the limits of experimental error of the microspirometer used. 2. The oxygen consumed in a microspirometer by the blood of patients with chronic myelogenous leucemia with a high white blood cell count, and of one with leucocytosis from sepsis, was proportional to the number of adult polymorphonuclear neutrophils in the blood. 3. No correlation could be made between the rate of oxygen absorption and the total number of white blood cells in the blood, or the total number of immature cells, or the number of red blood cells, or the amount of oxyhemoglobin. 4. The blood of patients with chronic myelogenous leucemia continued to use oxygen in the microspirometer longer than that of normal individuals, and the hemoglobin, in the leucemic bloods, became desaturated even though exposed to air. 5. In blood in which the bulk. of the cells were immature and the mature cells few, the oxygen consumption was lower than in blood in which the mature cells predominated. The rate of oxygen consumption of the immature cells was relatively low as compared to the mature. 6. The slower rate of oxygen absorption by the immature leucocytes in chronic myelogenous leucemia as compared to the mature cells, places them, in accord with Warburg's reports, in the class of the malignant tissues in this respect rather than in the group of young or embryonic cells.

  20. The responses of photosynthesis and oxygen consumption to short-term changes in temperature and irradiance in a cyanobacterial mat (Ebro Delta, Spain)

    DEFF Research Database (Denmark)

    Epping, E.H.G.; Kühl, Michael

    2000-01-01

    We have evaluated the effects of short-term changes in incident irradiance and temperature on oxygenic photosynthesis and oxygen consumption in a hypersaline cyanobacterial mat from the Ebro Delta, Spain, in which Microcoleus chthonoplastes was the dominant phototrophic organism. The mat was incu......We have evaluated the effects of short-term changes in incident irradiance and temperature on oxygenic photosynthesis and oxygen consumption in a hypersaline cyanobacterial mat from the Ebro Delta, Spain, in which Microcoleus chthonoplastes was the dominant phototrophic organism. The mat...... was incubated in the laboratory at 15, 20, 25 and 308C at incident irradiances ranging from 0 to 1000 mmol photons m22 s21. Oxygen microsensors were used to measure steady-state oxygen profiles and the rates of gross photosynthesis, which allowed the calculation of areal gross photosynthesis, areal net oxygen...... production, and oxygen consumption in the aphotic layer of the mat. The lowest surface irradiance that resulted in detectable rates of gross photosynthesis increased with increasing temperature from 50 mmol photons m22 s21 at 158C to 500 mmol photons m22 s21 at 308C. These threshold irradiances were also...

  1. Enhanced oxygen consumption in Herbaspirillum seropedicae fnr mutants leads to increased NifA mediated transcriptional activation.

    Science.gov (United States)

    Batista, Marcelo Bueno; Wassem, Roseli; Pedrosa, Fábio de Oliveira; de Souza, Emanuel Maltempi; Dixon, Ray; Monteiro, Rose Adele

    2015-05-07

    Orthologous proteins of the Crp/Fnr family have been previously implicated in controlling expression and/or activity of the NifA transcriptional activator in some diazotrophs. This study aimed to address the role of three Fnr-like proteins from H. seropedicae SmR1 in controlling NifA activity and consequent NifA-mediated transcription activation. The activity of NifA-dependent transcriptional fusions (nifA::lacZ and nifB::lacZ) was analysed in a series of H. seropedicae fnr deletion mutant backgrounds. We found that combined deletions in both the fnr1 and fnr3 genes lead to higher expression of both the nifA and nifB genes and also an increased level of nifH transcripts. Expression profiles of nifB under different oxygen concentrations, together with oxygen consumption measurements suggest that the triple fnr mutant has higher respiratory activity when compared to the wild type, which we believe to be responsible for greater stability of the oxygen sensitive NifA protein. This conclusion was further substantiated by measuring the levels of NifA protein and its activity in fnr deletion strains in comparison with the wild-type. Fnr proteins are indirectly involved in controlling the activity of NifA in H. seropedicae, probably as a consequence of their influence on respiratory activity in relation to oxygen availability. Additionally we can suggest that there is some redundancy in the physiological function of the three Fnr paralogs in this organism, since altered respiration and effects on NifA activity are only observed in deletion strains lacking both fnr1 and fnr3.

  2. Oxygen Consumption and Usage During Physical Exercise: The Balance Between Oxidative Stress and ROS-Dependent Adaptive Signaling

    Science.gov (United States)

    Zhao, Zhongfu; Koltai, Erika; Ohno, Hideki; Atalay, Mustafa

    2013-01-01

    Abstract The complexity of human DNA has been affected by aerobic metabolism, including endurance exercise and oxygen toxicity. Aerobic endurance exercise could play an important role in the evolution of Homo sapiens, and oxygen was not important just for survival, but it was crucial to redox-mediated adaptation. The metabolic challenge during physical exercise results in an elevated generation of reactive oxygen species (ROS) that are important modulators of muscle contraction, antioxidant protection, and oxidative damage repair, which at moderate levels generate physiological responses. Several factors of mitochondrial biogenesis, such as peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α), mitogen-activated protein kinase, and SIRT1, are modulated by exercise-associated changes in the redox milieu. PGC-1α activation could result in decreased oxidative challenge, either by upregulation of antioxidant enzymes and/or by an increased number of mitochondria that allows lower levels of respiratory activity for the same degree of ATP generation. Endogenous thiol antioxidants glutathione and thioredoxin are modulated with high oxygen consumption and ROS generation during physical exercise, controlling cellular function through redox-sensitive signaling and protein–protein interactions. Endurance exercise-related angiogenesis, up to a significant degree, is regulated by ROS-mediated activation of hypoxia-inducible factor 1α. Moreover, the exercise-associated ROS production could be important to DNA methylation and post-translation modifications of histone residues, which create heritable adaptive conditions based on epigenetic features of chromosomes. Accumulating data indicate that exercise with moderate intensity has systemic and complex health-promoting effects, which undoubtedly involve regulation of redox homeostasis and signaling. Antioxid. Redox Signal. 18, 1208–1246. PMID:22978553

  3. Oxygen Consumption of Elite Distance Runners on an Anti-Gravity Treadmill®

    Directory of Open Access Journals (Sweden)

    David K.P. McNeill, John R. Kline, Hendrick D. de Heer, J. Richard Coast

    2015-06-01

    Full Text Available Lower body positive pressure (LBPP, or ‘anti-gravity’ treadmills® have become increasingly popular among elite distance runners. However, to date, few studies have assessed the effect of body weight support (BWS on the metabolic cost of running among elite runners. This study evaluated how BWS influenced the relationship between velocity and metabolic cost among 6 elite male distance runners. Participants ran three- 16 minute tests consisting of 4 stages of 4 minutes at 8, 7, 6 and 5 min·mile−1 pace (3.35, 3.84, 4.47 and 5.36 m·s−1, while maintaining an aerobic effort (Respiratory Exchange Ratio ≤1.00. One test was run on a regular treadmill, one on an anti-gravity treadmill with 40% BWS and one with 20% BWS being provided. Expired gas data were collected and regression equations used to determine and compare slopes. Significant decreases in oxygen uptake (V̇O2 were found with each increase in BWS (p < 0.001. At 20% BWS, the average decrease in net VO2 was greater than proportional (34%, while at 40% BWS, the average net reduction in VO2 was close to proportional (38%. Across velocities, the slope of the relationship between VO2 and velocity (ΔV̇O2/Δv was steeper with less support. The slopes at both the 20% and 40% BWS conditions were similar, especially when compared to the regular treadmill. Variability in VO2 between athletes was much greater on the LBPP treadmill and was greater with increased levels of BWS. In this study we evaluated the effect of body weight support on V̇O2 among elite distance runners. We have shown that oxygen uptake decreased with support, but not in direct proportion to that support. Further, because of the high variability in oxygen uptake between athletes on the LBPP treadmill, prediction equations may not be reliable and other indicators (heart rate, perceived exertion or directly measured oxygen uptake should be used to guide training intensity when training on the LBPP treadmill.

  4. Oxygen consumption and mortality rate of mice after X radiation under the influence of magnetic fields

    International Nuclear Information System (INIS)

    Rekbi, M.

    1984-01-01

    In this work it was studied whether an influence on the oxygen use was to be expected as a result of a magnetic pulsating field. This could not be determined. An increased effect of the magnetic field with respect to the reduction of the mortality rate was, however, to be observed. Thereby the influence of similar constant and pulsating fields was discussed from various perspectives. The question of the biological effect mechanism of the magnetic field (main issue of the influence of the magnetic field during or after the irradiation) can only be answered by further comprehensive investigations. (orig./MG) [de

  5. Event-Associated Oxygen Consumption Rate Increases ca. Five-Fold When Interictal Activity Transforms into Seizure-Like Events In Vitro

    Directory of Open Access Journals (Sweden)

    Karl Schoknecht

    2017-09-01

    Full Text Available Neuronal injury due to seizures may result from a mismatch of energy demand and adenosine triphosphate (ATP synthesis. However, ATP demand and oxygen consumption rates have not been accurately determined, yet, for different patterns of epileptic activity, such as interictal and ictal events. We studied interictal-like and seizure-like epileptiform activity induced by the GABAA antagonist bicuculline alone, and with co-application of the M-current blocker XE-991, in rat hippocampal slices. Metabolic changes were investigated based on recording partial oxygen pressure, extracellular potassium concentration, and intracellular flavine adenine dinucleotide (FAD redox potential. Recorded data were used to calculate oxygen consumption and relative ATP consumption rates, cellular ATP depletion, and changes in FAD/FADH2 ratio by applying a reactive-diffusion and a two compartment metabolic model. Oxygen-consumption rates were ca. five times higher during seizure activity than interictal activity. Additionally, ATP consumption was higher during seizure activity (~94% above control than interictal activity (~15% above control. Modeling of FAD transients based on partial pressure of oxygen recordings confirmed increased energy demand during both seizure and interictal activity and predicted actual FAD autofluorescence recordings, thereby validating the model. Quantifying metabolic alterations during epileptiform activity has translational relevance as it may help to understand the contribution of energy supply and demand mismatches to seizure-induced injury.

  6. Persistent increase in oxygen consumption and impaired neurovascular coupling after spreading depression in rat neocortex.

    Science.gov (United States)

    Piilgaard, Henning; Lauritzen, Martin

    2009-09-01

    Cortical spreading depression (CSD) is associated with a dramatic failure of brain ion homeostasis and increased energy metabolism. There is strong clinical and experimental evidence to suggest that CSD is the mechanism of migraine, and involved in progressive neuronal injury in stroke and head trauma. Here we tested the hypothesis that single episodes of CSD induced acute hypoxia, and prolonged impairment of neurovascular and neurometabolic coupling. Cortical spreading depression was induced in rat frontal cortex, whereas cortical electrical activity and local field potentials (LFPs) were recorded by glass microelectrodes, cerebral blood flow (CBF) by laser-Doppler flowmetry, and tissue oxygen tension (tpO(2)) with polarographic microelectrodes. Cortical spreading depression increased cerebral metabolic rate of oxygen (CMRO(2)) by 71%+/-6.7% and CBF by 238%+/-48.1% for 1 to 2 mins. For the following 2 h, basal tpO(2) and CBF were reduced whereas basal CMRO(2) was persistently elevated by 8.1%+/-2.9%. In addition, within first hour after CSD we found impaired neurovascular coupling (LFP versus CBF), whereas neurometabolic coupling (LFP versus CMRO(2)) remained unaffected. Impaired neurovascular coupling was explained by both reduced vascular reactivity and suppressed function of cortical inhibitory interneurons. The protracted effects of CSD on basal CMRO(2) and neurovascular coupling may contribute to cellular dysfunction in patients with migraine and acutely injured cerebral cortex.

  7. Regional cerebral blood flow and oxygen consumption during normal human sleep

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Ken [Toho Univ., Tokyo (Japan). School of Medicine

    1989-09-01

    Regional cerebral blood flow (rCBF), regional oxygen extraction fraction (rCEF) and regional cerebral metabolic rate for oxygen (rCMRO{sub 2}) were measured using the continuous inhalation technique for {sup 15}O with positron emission tomography (PET) during both wakefulness and sleep. Ten paid volunteers, with a mean age of 21.6 yrs., were deprived of sleep for a period of approximately 20 hours, and the experiments were performed mostly in the morning. {sup 15}O activity of both whole blood and the plasma, pixel count of PET, total arterial blood oxygen content were used for analysis of rCBF, rOEF and rCMRO{sub 2}. PET scannings were carried out mostly during the very light non-rapid eye movement (NREM) sleep, i.e. stage 1 and/or 2, and wakefulness. About 10 minutes after the start of continuous inhalation of {sup 15}O gas, the {sup 15}O activity of the brain was found to be in a steady-state condition. During this steady-state condition, PET scannings were performed for about 10 minutes. Regions of interest, square in shape and having an area of 2.8 cm{sup 3}, were set in each cortex on PET images of a horizontal cross-section of the brain, set at 45 mm above the orbitomeatal line. The rCBF and rCMRO{sub 2} were analysed in 5 of 10 male subjects during both wakefulness and NREM sleep, and only 3 were done during three sleep stages, including REM sleep. Levels of rCBF and rCMRO{sub 2} were found to be decreased in NREM sleep, and the decreasing rates were calculated at 10.2% and 7.6% from the level of wakefulness, respectively. There was no significant difference in the mean value of rOEF between wakefulness and NREM sleep. There were no significant regional differences found in the rate of decrease among the frontal, temporal and occipital cortices. It was considered that the decrease of rCBF and rCMRO{sub 2} during NREM sleep suggested a decrease of the activity levels in the cerebral functions. (author).

  8. Regional cerebral blood flow and oxygen consumption during normal human sleep

    International Nuclear Information System (INIS)

    Takahashi, Ken

    1989-01-01

    Regional cerebral blood flow (rCBF), regional oxygen extraction fraction (rCEF) and regional cerebral metabolic rate for oxygen (rCMRO 2 ) were measured using the continuous inhalation technique for 15 O with positron emission tomography (PET) during both wakefulness and sleep. Ten paid volunteers, with a mean age of 21.6 yrs., were deprived of sleep for a period of approximately 20 hours, and the experiments were performed mostly in the morning. 15 O activity of both whole blood and the plasma, pixel count of PET, total arterial blood oxygen content were used for analysis of rCBF, rOEF and rCMRO 2 . PET scannings were carried out mostly during the very light non-rapid eye movement (NREM) sleep, i.e. stage 1 and/or 2, and wakefulness. About 10 minutes after the start of continuous inhalation of 15 O gas, the 15 O activity of the brain was found to be in a steady-state condition. During this steady-state condition, PET scannings were performed for about 10 minutes. Regions of interest, square in shape and having an area of 2.8 cm 3 , were set in each cortex on PET images of a horizontal cross-section of the brain, set at 45 mm above the orbitomeatal line. The rCBF and rCMRO 2 were analysed in 5 of 10 male subjects during both wakefulness and NREM sleep, and only 3 were done during three sleep stages, including REM sleep. Levels of rCBF and rCMRO 2 were found to be decreased in NREM sleep, and the decreasing rates were calculated at 10.2% and 7.6% from the level of wakefulness, respectively. There was no significant difference in the mean value of rOEF between wakefulness and NREM sleep. There were no significant regional differences found in the rate of decrease among the frontal, temporal and occipital cortices. It was considered that the decrease of rCBF and rCMRO 2 during NREM sleep suggested a decrease of the activity levels in the cerebral functions. (author)

  9. Temperature dependence of microbial degradation of organic matter in marine sediments: polysaccharide hydrolysis, oxygen consumption, and sulfate reduction

    DEFF Research Database (Denmark)

    Arnosti, C.; Jørgensen, BB; Sagemann, J.

    1998-01-01

    The temperature dependence of representative initial and terminal steps of organic carbon remineralization was measured at 2 temperate sites with annual temperature ranges of 0 to 30 degrees C and 4 to 15 degrees C and 2 Arctic sites with temperatures of 2.6 and -1.7 degrees C. Slurried sediments...... were incubated in a temperature gradient block spanning a temperature range of ca 45 degrees C. The initial step of organic carbon remineralization, macromolecule hydrolysis, was measured via the enzymatic hydrolysis of fluorescently labeled polysaccharides. The terminal steps of organic carbon...... remineralization were monitored through consumption of oxygen and reduction of (SO42-)-S-35. At each of the 4 sites, the temperature response of the initial step of organic carbon remineralization was similar to that of the terminal steps. Although optimum temperatures were always well above ambient environmental...

  10. Measurement of local blood flow and oxygen consumption in evolving irreversible cerebral infarction: an in vivo study in man

    International Nuclear Information System (INIS)

    Baron, J.C.; Rougemont, D.; Lebrun-Grandie, P.; Bousser, M.G.; Cabanis, E.; Bories, J.; Comar, D.; Castaigne, P.

    1982-09-01

    Positron emission tomography (PET) allows in vivo measurement of local cerebral blood flow (1CBF), oxygen consumption rate (1CMRO 2 ) and glucose utilisation (1CMRG1c) in man. Although 1CMRG1c is accessible in animals, this is not the case for 1CMRO 2 , an excellent index of local functional state. PET imaging of the local interrelationship of CBF and metabolism in completed ischemic stroke has attracted considerable interest because of its potential to differentiate irreversibly damaged from viable tissue on the basis of the CBF- metabolism patterns. Several qualitative or semi-quantitative pioneering studies provided a limited insight into this question, while the single truly quantitative study was only briefly reported. We report here a detailed study of the local CBF-CMRO 2 quantitative patterns in irreversibly infarcted brain regions

  11. Methane emission and oxygen consumption in the hydroelectric dam of Petit Saut in French Guyana

    International Nuclear Information System (INIS)

    Galy-Lacaux, C.; Jambert, C.; Delmas, R.; Dumestre, J.F.; Labroue, L.; Cerdan, P.; Richard, S.

    1996-01-01

    Methane emissions from the hydroelectric dam of Petit-Saut, in French Guyana, were measured over a 20-months period. Since the beginning of the reservoir filling (January 1994), 300 km 2 of tropical forest have been submerged. Biological CH 4 oxidation, in the surface water of the lake and in the river downstream of the dam, lead to an intense 0 2 consumption. Emissions of CH 4 by diffusion into the atmosphere or by degassing of the water released into the river as well as the stock of dissolved gas in the lake, and their temporal dynamics, were studied. Maximum emissions of 700 t (CH 4 ) per day were attained in February 1994, corresponding to maximum dissolved CH 4 concentrations of 14 mg l -1 in the water column. Total emissions since January 1994, were calculated from the whole data set. (authors). 7 refs., 2 figs., 1 tab

  12. Regional myocardial oxygen consumption determined noninvasively in humans with [1-11C]acetate and dynamic positron tomography

    International Nuclear Information System (INIS)

    Armbrecht, J.J.; Buxton, D.B.; Brunken, R.C.; Phelps, M.E.; Schelbert, H.R.

    1989-01-01

    Experimental studies of animals have previously demonstrated the validity of [1-11C]acetate as a tracer of oxidative metabolism for use with positron emission tomography. The present study was undertaken to define in normal human volunteers the relation between myocardial clearance kinetics of [1-11C]acetate, and the rate-pressure product as an index of myocardial oxygen consumption. Twenty-two studies were performed of 12 volunteers. The rate-pressure product was increased with continuous supine bicycle exercise in six studies. Of the 16 resting studies, seven were performed in the fasted state and nine following an oral glucose load, to define possible effects of substrate availability on the tracer-tissue kinetics. Myocardial tissue time-activity curves were biexponential. Clearance of activity was homogeneous throughout the myocardium. The rate constants k1, obtained from biexponential fitting, and kmono, obtained by monoexponential fitting of the initial linear portion of the time-activity curves, correlated well with the rate-pressure product. Although the correlation coefficient was higher for k1 than for kmono (0.95 vs. 0.91), analysis on a sectorial basis showed less regional variability in kmono. This suggests that kmono, which is more practical than k1 because it requires shorter acquisition times, may be more clinically and experimentally useful for detection of myocardial segments with abnormal oxygen consumption. Overall, changes in myocardial substrate supply were without significant effect on the relation between the rate constants (k1 and kmono) and the rate-pressure product, although a small decrease in kmono/rate-pressure product was observed following oral glucose by paired analysis in four subjects

  13. The relationship between heart rate and rate of oxygen consumption in Galapagos marine iguanas (Amblyrhynchus cristatus) at two different temperatures.

    Science.gov (United States)

    Butler, Patrick J; Frappell, Peter B; Wang, Tobias; Wikelski, Martin

    2002-07-01

    To enable the use of heart rate (fH) for estimating field metabolic rate (FMR) in free-ranging Galapagos marine iguanas Amblyrhynchus cristatus, we determined the relationships between fH and mass-specific rate of oxygen consumption (sVO2) in seven iguanas before and during exercise on a treadmill and during the post-exercise period. The experiments were conducted at 27 and 35 degrees C, which are the temperatures that represent the lowest and highest average body temperatures of these animals in the field during summer. There were linear and significant relationships between fH and sVO2 at both temperatures (r(2)=0.86 and 0.91 at 27 degrees C and 36 degrees C, respectively). The slopes of the two regression lines did not differ, but there were significant differences in their intercepts. Thus, while heart rate can be used to predict FMR, the effects of temperature on the intercept of the regression must be taken into account when converting fH to sVO2. On the basis of our data, this can be achieved by applying the following formula: sVO2=0.0113fH-0.2983Q(10)((T(b)-27)/10). The increase in sVO2 with elevated body temperature results from an increase in fH, with no significant change in mass-specific oxygen pulse (sO(2) pulse; cardiac stroke volume times the difference in oxygen content between arterial and mixed venous blood). However, during exercise at both temperatures, increases in fH are insufficient to provide all of the additional O(2) required and there are also significant increases in the sO(2) pulses. This creates the situation whereby the same fH at the two temperatures can represent different values of sVO2.

  14. Hepatic blood flow and splanchnic oxygen consumption in patients with liver failure. Effect of high-volume plasmapheresis.

    Science.gov (United States)

    Clemmesen, J O; Gerbes, A L; Gülberg, V; Hansen, B A; Larsen, F S; Skak, C; Tygstrup, N; Ott, P

    1999-02-01

    Liver failure represents a major therapeutic challenge, and yet basic pathophysiological questions about hepatic perfusion and oxygenation in this condition have been poorly investigated. In this study, hepatic blood flow (HBF) and splanchnic oxygen delivery (DO2, sp) and oxygen consumption (VO2,sp) were assessed in patients with liver failure defined as hepatic encephalopathy grade II or more. Measurements were repeated after high-volume plasmapheresis (HVP) with exchange of 8 to 10 L of plasma. HBF was estimated by use of constant infusion of D-sorbitol and calculated according to Fick's principle from peripheral artery and hepatic vein concentrations. In 14 patients with acute liver failure (ALF), HBF (1.78 +/- 0.78 L/min) and VO2,sp (3.9 +/- 0.9 mmol/min) were higher than in 11 patients without liver disease (1.07 +/- 0.19 L/min, P HVP, HBF increased from 1.67 +/- 0.72 to 2.07 +/- 1.11 L/min (n=11) in ALF, and from 1.89 +/- 1.32 to 2.34 +/- 1.54 L/min (n=7) in AOCLD, P HVP. Blood flow was redirected to the liver as the systemic vascular resistance index increased (1,587 +/- 650 vs. 2, 020 +/- 806 Dyne. s. cm-5. m2, P HVP, but as cardiac output increased from 9.1 +/- 2.8 to 10.1 +/- 2.9 L/min (P HVP (n=18), DO2,sp increased by 15% (P HVP. Changes of ET-1 were positively correlated with changes in HBF (P HVP (P HVP did not correlate. Our data suggest that liver failure is associated with increased HBF and VO2, sp. HVP further increased HBF and DO2,sp but VO2,sp was unchanged, indicating that splanchnic hypoxia was not present.

  15. Modeling of oxygen gas diffusion and consumption during the oxic transient in a disposal cell of radioactive waste

    International Nuclear Information System (INIS)

    De Windt, Laurent; Marsal, François; Corvisier, Jérôme; Pellegrini, Delphine

    2014-01-01

    Highlights: • This paper deals with the geochemistry of underground HLW disposals. • The oxic transient is a key issue in performance assessment (e.g. corrosion, redox). • A reactive transport model is explicitly coupled to gas diffusion and reactivity. • Application to in situ experiment (Tournemire laboratory) and HLW disposal cell. • Extent of the oxidizing/reducing front is investigated by sensitivity analysis. - Abstract: The oxic transient in geological radioactive waste disposals is a key issue for the performance of metallic components that may undergo high corrosion rates under such conditions. A previous study carried out in situ in the argillite formation of Tournemire (France) has suggested that oxic conditions could have lasted several years. In this study, a multiphase reactive transport model is performed with the code HYTEC to analyze the balance between the kinetics of pyrite oxidative dissolution, the kinetics of carbon steel corrosion and oxygen gas diffusion when carbon steel components are emplaced in the geological medium. Two cases were modeled: firstly, the observations made in situ have been reproduced, and the model established was then applied to a disposal cell for high-level waste (HLW) in an argillaceous formation, taking into account carbon steel components and excavated damaged zones (EDZ). In a closed system, modeling leads to a complete and fast consumption of oxygen in both cases. Modeling results are more consistent with the in situ test while considering residual voids between materials and/or a water unsaturated state allowing for oxygen gas diffusion (open conditions). Under similar open conditions and considering ventilation of the handling drifts, a redox contrast occurs between reducing conditions at the back of the disposal cell (with anoxic corrosion of steel and H 2 production) and oxidizing conditions at the front of the cell (with oxic corrosion of steel). The extent of the oxidizing/reducing front in the

  16. Critical oxygen tension and the effect of hypoxia on the oxygen consumption of the striped catfish, Pangasius hypophthaimos (Pangasiidae)

    DEFF Research Database (Denmark)

    Lefevre, S.; Bayley, Mark; Wang, Tobias

    2008-01-01

    The striped catfish (Pangasius hypophthalmus) is an air-breathing teleost that uses a modified swim bladder for aerial gas exchange. Pangasius is of enormous importance for aquaculture industry in the Mekong Delta(Vietnam), but little is known about its physiology. We have initiated a series...... consumption (VO2), measured with intermittent closed respirometry, was 67.8 ± 5.1 mLO2/kg/h when the fish were maintained without access to air at 27 °C. The critical oxygen tension (Pcrit) at these conditions was 57.9 ± 8.9 mmHg (N = 7). The metabolic response to aquatic hypoxia was studied in fish subjected....... The ontogenetic effect of environmental PO2 on metabolism is currently under investigation with fish being reared in 30%, 60% and 100% saturation. Data on resting VO2and Pcrit will be presented and discussed for these animals....

  17. Low Oxygen Consumption is Related to a Hypomethylation and an Increased Secretion of IL-6 in Obese Subjects with Sleep Apnea-Hypopnea Syndrome.

    Science.gov (United States)

    Lopez-Pascual, Amaya; Lasa, Arrate; Portillo, María P; Arós, Fernando; Mansego, María L; González-Muniesa, Pedro; Martinez, J Alfredo

    2017-01-01

    Deoxyribonucleic acid (DNA) methylation is an epigenetic modification involved in gene expression regulation, usually via gene silencing, which contributes to the risks of many multifactorial diseases. The aim of the present study was to analyze the influence of resting oxygen consumption on global and gene DNA methylation as well as protein secretion of inflammatory markers in blood cells from obese subjects with sleep apnea-hypopnea syndrome (SAHS). A total of 44 obese participants with SAHS were categorized in 2 groups according to their resting oxygen consumption. DNA methylation levels were evaluated using a methylation-sensitive high resolution melting approach. The analyzed interleukin 6 (IL6) gene cytosine phosphate guanine (CpG) islands showed a hypomethylation, while serum IL-6 was higher in the low compared to the high oxygen consumption group (p DNA methylation of tumor necrosis factor (B = -0.82, 95% CI -1.33 to -0.30) and long interspersed nucleotide element 1 (B = -0.46; 95% CI -0.87 to -0.04) gene CpGs were found. Finally, studied CpG methylation levels of serpin peptidase inhibitor, clade E member 1 (r = 0.43; p = 0.01), and IL6 (r = 0.41; p = 0.02) were positively associated with fat-free mass. These findings suggest a potential role of oxygen in the regulation of inflammatory genes. Oxygen consumption measurement at rest could be proposed as a clinical biomarker of metabolic health. © 2017 S. Karger AG, Basel.

  18. Cardiorespiratory responses of a dance session designed for older women: A cross sectional study.

    Science.gov (United States)

    Rodrigues-Krause, Josianne; Farinha, Juliano Boufleur; Ramis, Thiago Rozales; Boeno, Francesco Pinto; Dos Santos, Gabriela Cristina; Krause, Mauricio; Reischak-Oliveira, Alvaro

    2018-06-04

    Dancing has been increasingly used as a type of exercise intervention to improve cardiovascular fitness of older people. However, it is unclear which may be the exercise intensity of the dance sessions. To describe cardiorespiratory responses of a dance session for older women, and to identify intensity zones in relation to peak oxygen consumption (VO 2 peak), first and second ventilatory thresholds (VT1 and VT2). Ten women (66 ± 5 yrs., BMI 27 ± 4) were examined on three occasions: Familiarization, maximum effort and dance sessions. Incremental treadmill test: 5 km/h, 2% slope each min, until maximum effort. Dance class (60 min): warm-up (20 min), across-the-floor (10 min), choreography (15 min), show (10 min) and cool-down (5 min). Ventilatory parameters were measured continuously (breath-by-breath). VO 2 (mL·kg -1 ·min -1 ): Maximum effort: VO 2 peak (23.3 ± 4.3), VT1 (17.2 ± 3.5) and VT2 (20.9 ± 3.4). Dancing: warm-up (12.8 ± 2.4, ~55%VO 2 peak), across-the-floor (14.2 ± 2.4 ~62%VO 2 peak), choreography (14.6 ± 3.2 ~63%VO 2 peak) and show (16.1 ± 3.3, ~69% VO 2 peak). Show was similar to VT1. Cardiorespiratory demands of a dance class for older women are at low aerobic intensity. Show was similar to VT1, indicating that a dance class may be modulated to improve aerobic fitness, at least at initial stages of training. Copyright © 2018 Elsevier Inc. All rights reserved.

  19. Coalbed gas desorption in canisters: Consumption of trapped atmospheric oxygen and implications for measured gas quality

    International Nuclear Information System (INIS)

    Jin, Hui; Schimmelmann, Arndt; Mastalerz, Maria; Pope, James; Moore, Tim A.

    2010-01-01

    Desorption canisters are routinely employed to quantify coalbed gas contents in coals. If purging with inert gas or water flooding is not used, entrapment of air with ∝ 78.08 vol.% nitrogen (N 2 ) in canisters during the loading of coal results in contamination by air and subsequent overestimates of N 2 in desorbed coalbed gas. Pure coalbed gas does not contain any elemental oxygen (O 2 ), whereas air contamination originally includes ∝ 20.95 vol.% O 2 and has a N 2 /O 2 volume ratio of ∝ 3.73. A correction for atmospheric N 2 is often attempted by quantifying O 2 in headspace gas and then proportionally subtracting atmospheric N 2 . However, this study shows that O 2 is not a conservative proxy for air contamination in desorption canisters. Time-series of gas chromatographic (GC) compositional data from several desorption experiments using high volatile bituminous coals from the Illinois Basin and a New Zealand subbituminous coal document that atmospheric O 2 was rapidly consumed, especially during the first 24 h. After about 2 weeks of desorption, the concentration of O 2 declined to near or below GC detection limits. Irreversible loss of O 2 in desorption canisters is caused by biological, chemical, and physical mechanisms. The use of O 2 as a proxy for air contamination is justified only immediately after loading of desorption canisters, but such rapid measurements preclude meaningful assessment of coalbed gas concentrations. With increasing time and progressive loss of O 2 , the use of O 2 content as a proxy for atmospheric N 2 results in overestimates of N 2 in desorbed coalbed gas. The indicated errors for nitrogen often range in hundreds of %. Such large analytical errors have a profound influence on market choices for CBM gas. An erroneously calculated N 2 content in CBM would not meet specifications for most pipeline-quality gas. (author)

  20. Regulation of ventilation and oxygen consumption by delta- and mu-opioid receptor agonists.

    Science.gov (United States)

    Schaeffer, J I; Haddad, G G

    1985-09-01

    To study the effect of endorphins on metabolic rate and on the relationship between O2 consumption (VO2) and ventilation, we administered enkephalin analogues (relatively selective delta-receptor agonists) and a morphiceptin analogue (a highly selective mu-receptor agonist) intracisternally in nine unanesthetized chronically instrumented adult dogs. Both delta- and mu-agonists decreased VO2 by 40-60%. delta-Agonists induced a dose-dependent decrease in mean instantaneous minute ventilation (VT/TT) associated with periodic breathing. The decrease in VT/TT started and resolved prior to the decrease and returned to baseline of VO2, respectively. In contrast, the mu-agonists induced an increase in VT/TT associated with rapid shallow breathing. Arterial PCO2 increased and arterial PO2 decreased after both delta- and mu-agonists. Low doses of intracisternal naloxone (0.002-2.0 micrograms/kg) reversed the opioid effect on VT/TT but not on VO2; higher doses of naloxone (5-25 micrograms/kg) reversed both. Naloxone administered alone had no effect on VT/TT or VO2. These data suggest that 1) both delta- and mu-agonists induce alveolar hypoventilation despite a decrease in VO2, 2) this hypoventilation results from a decrease in VT/TT after delta-agonists but an increase in dead space ventilation after mu-agonists, and 3) endorphins do not modulate ventilation and metabolic rate tonically, but we speculate that they may do so in response to stressful stimulation.

  1. Coalbed gas desorption in canisters: Consumption of trapped atmospheric oxygen and implications for measured gas quality

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Hui; Schimmelmann, Arndt [Indiana University, Dept. of Geological Sciences, Bloomington, IN 47405-1405 (United States); Mastalerz, Maria [Indiana University, Indiana Geological Survey, Bloomington, IN 47405-2208 (United States); Pope, James [CRL Energy Ltd., 123 Blenheim Road, Christchurch (New Zealand); University of Canterbury, Dept. of Geological Sciences, Christchurch (New Zealand); Moore, Tim A. [University of Canterbury, Dept. of Geological Sciences, Christchurch (New Zealand); P.T. Arrow Energy Indonesia, Wisma Anugraha, Jl. Taman Kemang No. 32B, Jakarta Selatan (Indonesia)

    2010-01-07

    Desorption canisters are routinely employed to quantify coalbed gas contents in coals. If purging with inert gas or water flooding is not used, entrapment of air with {proportional_to} 78.08 vol.% nitrogen (N{sub 2}) in canisters during the loading of coal results in contamination by air and subsequent overestimates of N{sub 2} in desorbed coalbed gas. Pure coalbed gas does not contain any elemental oxygen (O{sub 2}), whereas air contamination originally includes {proportional_to} 20.95 vol.% O{sub 2} and has a N{sub 2}/O{sub 2} volume ratio of {proportional_to} 3.73. A correction for atmospheric N{sub 2} is often attempted by quantifying O{sub 2} in headspace gas and then proportionally subtracting atmospheric N{sub 2}. However, this study shows that O{sub 2} is not a conservative proxy for air contamination in desorption canisters. Time-series of gas chromatographic (GC) compositional data from several desorption experiments using high volatile bituminous coals from the Illinois Basin and a New Zealand subbituminous coal document that atmospheric O{sub 2} was rapidly consumed, especially during the first 24 h. After about 2 weeks of desorption, the concentration of O{sub 2} declined to near or below GC detection limits. Irreversible loss of O{sub 2} in desorption canisters is caused by biological, chemical, and physical mechanisms. The use of O{sub 2} as a proxy for air contamination is justified only immediately after loading of desorption canisters, but such rapid measurements preclude meaningful assessment of coalbed gas concentrations. With increasing time and progressive loss of O{sub 2}, the use of O{sub 2} content as a proxy for atmospheric N{sub 2} results in overestimates of N{sub 2} in desorbed coalbed gas. The indicated errors for nitrogen often range in hundreds of %. Such large analytical errors have a profound influence on market choices for CBM gas. An erroneously calculated N{sub 2} content in CBM would not meet specifications for most pipeline

  2. Noninvasive determination of myocardial blood flow, oxygen consumption and efficiency in normal humans by carbon-11 acetate positron emission tomography imaging

    International Nuclear Information System (INIS)

    Porenta, G.; Cherry, S.; Czernin, J.; Brunken, R.; Kuhle, W.; Hashimoto, T.; Schelbert, H.R.

    1999-01-01

    The aims of this study were: (1) to measure noninvasively and near simultaneously myocardial blood flow, oxygen consumption, and contractile function and (2) to analyze myocardial energy expenditure and efficiency at rest and during dobutamine stress in normal humans. Dynamic and gated carbon-11 acetate positron emission tomography (PET) imaging was performed in 11 normal subjects. The initial uptake of 11 C-acetate was measured to estimate myocardial blood flow. Oxygen consumption was derived from the monoexponential slope of the 11 C-clearance curve recorded during myocardial washout. ECG-gated systolic and diastolic images were acquired during the peak myocardial 11 C activity to measure left ventricular radius, myocardial wall thickness, and long axis length. Myocardial oxygen consumption and parameters of cardiac geometry were used to determine myocardial energetics and cardiac efficiency by tension-area area analysis. Myocardial blood flow averaged 0.8±0.06 ml min -1 g -1 at rest and 1.48±0.15 ml min -1 g -1 during dobutamine stress. Oxygen delivery and consumption were 151±13 and 88±15 μl O 2 min -1 g -1 at rest and increased to 291±31 and 216±31 μl O 2 min -1 g -1 , respectively, during pharmacological stress (P 11 C acetate imaging provides the unique capability to study noninvasively determinants of myocardial energy delivery, expenditure, and efficiency. (orig.)

  3. Bilateral changes in forearm oxygen consumption at rest and after exercise in patients with unilateral Repetitive Strain Injury : A case control study

    NARCIS (Netherlands)

    J. Oosterhof; D. Thijssen; M. Hopman; J. Brunnekreef

    2011-01-01

    To investigate whether oxygen consumption and blood flow at rest and after exercise are lower in the affected arm of patients with repetitive strain injury (RSI) compared to controls, and lower in the healthy nonaffected forearm within patients with unilateral RSI. RSI is considered an upper

  4. Pyruvate induces transient tumor hypoxia by enhancing mitochondrial oxygen consumption and potentiates the anti-tumor effect of a hypoxia-activated prodrug TH-302.

    Directory of Open Access Journals (Sweden)

    Yoichi Takakusagi

    Full Text Available BACKGROUND: TH-302 is a hypoxia-activated prodrug (HAP of bromo isophosphoramide mustard that is selectively activated within hypoxic regions in solid tumors. Our recent study showed that intravenously administered bolus pyruvate can transiently induce hypoxia in tumors. We investigated the mechanism underlying the induction of transient hypoxia and the combination use of pyruvate to potentiate the anti-tumor effect of TH-302. METHODOLOGY/RESULTS: The hypoxia-dependent cytotoxicity of TH-302 was evaluated by a viability assay in murine SCCVII and human HT29 cells. Modulation in cellular oxygen consumption and in vivo tumor oxygenation by the pyruvate treatment was monitored by extracellular flux analysis and electron paramagnetic resonance (EPR oxygen imaging, respectively. The enhancement of the anti-tumor effect of TH-302 by pyruvate treatment was evaluated by monitoring the growth suppression of the tumor xenografts inoculated subcutaneously in mice. TH-302 preferentially inhibited the growth of both SCCVII and HT29 cells under hypoxic conditions (0.1% O2, with minimal effect under aerobic conditions (21% O2. Basal oxygen consumption rates increased after the pyruvate treatment in SCCVII cells in a concentration-dependent manner, suggesting that pyruvate enhances the mitochondrial respiration to consume excess cellular oxygen. In vivo EPR oxygen imaging showed that the intravenous administration of pyruvate globally induced the transient hypoxia 30 min after the injection in SCCVII and HT29 tumors at the size of 500-1500 mm(3. Pretreatment of SCCVII tumor bearing mice with pyruvate 30 min prior to TH-302 administration, initiated with small tumors (∼ 550 mm(3, significantly delayed tumor growth. CONCLUSIONS/SIGNIFICANCE: Our in vitro and in vivo studies showed that pyruvate induces transient hypoxia by enhancing mitochondrial oxygen consumption in tumor cells. TH-302 therapy can be potentiated by pyruvate pretreatment if started at the

  5. Pyruvate induces transient tumor hypoxia by enhancing mitochondrial oxygen consumption and potentiates the anti-tumor effect of a hypoxia-activated prodrug TH-302.

    Science.gov (United States)

    Takakusagi, Yoichi; Matsumoto, Shingo; Saito, Keita; Matsuo, Masayuki; Kishimoto, Shun; Wojtkowiak, Jonathan W; DeGraff, William; Kesarwala, Aparna H; Choudhuri, Rajani; Devasahayam, Nallathamby; Subramanian, Sankaran; Munasinghe, Jeeva P; Gillies, Robert J; Mitchell, James B; Hart, Charles P; Krishna, Murali C

    2014-01-01

    TH-302 is a hypoxia-activated prodrug (HAP) of bromo isophosphoramide mustard that is selectively activated within hypoxic regions in solid tumors. Our recent study showed that intravenously administered bolus pyruvate can transiently induce hypoxia in tumors. We investigated the mechanism underlying the induction of transient hypoxia and the combination use of pyruvate to potentiate the anti-tumor effect of TH-302. The hypoxia-dependent cytotoxicity of TH-302 was evaluated by a viability assay in murine SCCVII and human HT29 cells. Modulation in cellular oxygen consumption and in vivo tumor oxygenation by the pyruvate treatment was monitored by extracellular flux analysis and electron paramagnetic resonance (EPR) oxygen imaging, respectively. The enhancement of the anti-tumor effect of TH-302 by pyruvate treatment was evaluated by monitoring the growth suppression of the tumor xenografts inoculated subcutaneously in mice. TH-302 preferentially inhibited the growth of both SCCVII and HT29 cells under hypoxic conditions (0.1% O2), with minimal effect under aerobic conditions (21% O2). Basal oxygen consumption rates increased after the pyruvate treatment in SCCVII cells in a concentration-dependent manner, suggesting that pyruvate enhances the mitochondrial respiration to consume excess cellular oxygen. In vivo EPR oxygen imaging showed that the intravenous administration of pyruvate globally induced the transient hypoxia 30 min after the injection in SCCVII and HT29 tumors at the size of 500-1500 mm(3). Pretreatment of SCCVII tumor bearing mice with pyruvate 30 min prior to TH-302 administration, initiated with small tumors (∼ 550 mm(3)), significantly delayed tumor growth. Our in vitro and in vivo studies showed that pyruvate induces transient hypoxia by enhancing mitochondrial oxygen consumption in tumor cells. TH-302 therapy can be potentiated by pyruvate pretreatment if started at the appropriate tumor size and oxygen concentration.

  6. Oxygen and SO2 Consumption Rates in White and Rosé Wines: Relationship with and Effects on Wine Chemical Composition.

    Science.gov (United States)

    Carrascón, Vanesa; Bueno, Mónica; Fernandez-Zurbano, Purificación; Ferreira, Vicente

    2017-11-01

    This Article addresses the study of O 2 and SO 2 consumption rates of white and rosé wines, their relationship to the initial chemical composition, and their effects on the chemical changes experienced by wine during oxidation. Eight wines were subjected to five consecutive air-saturation cycles. O 2 was monitored periodically; SO 2 , color, and antioxidant indexes were determined after each cycle, and the initial and final compositions of the wines were thoroughly determined. Wines consumed oxygen at progressively decreasing rates. In the last cycles, after a strong decrease, consistent increases of oxygen levels were seen. Oxygen consumption rates were satisfactorily modeled, being proportional to wine copper, quercetin, and kaempherol contents and negatively proportional to cinnamic acids. SO 2 consumption rates were highly diverse between wines and were positively related to free SO 2 , Mn, and pH, among others. In the last saturations, SO 2 consumption took place regardless of O 2 consumption, implying that SO 2 should reduce chemical species oxidized in previous saturations. Some volatile phenols seem to be the end point of radical-mediated oxidation of polyphenols taking place preferably in the first saturation.

  7. Wii, Kinect, and Move. Heart Rate, Oxygen Consumption, Energy Expenditure, and Ventilation due to Different Physically Active Video Game Systems in College Students.

    Science.gov (United States)

    Scheer, Krista S; Siebrant, Sarah M; Brown, Gregory A; Shaw, Brandon S; Shaw, Ina

    Nintendo Wii, Sony Playstation Move , and Microsoft XBOX Kinect are home video gaming systems that involve player movement to control on-screen game play. Numerous investigations have demonstrated that playing Wii is moderate physical activity at best, but Move and Kinect have not been as thoroughly investigated. The purpose of this study was to compare heart rate, oxygen consumption, and ventilation while playing the games Wii Boxing, Kinect Boxing, and Move Gladiatorial Combat. Heart rate, oxygen consumption, and ventilation were measured at rest and during a graded exercise test in 10 males and 9 females (19.8 ± 0.33 y, 175.4 ± 2.0 cm, 80.2 ± 7.7 kg,). On another day, in a randomized order, the participants played Wii Boxing, K inect Boxing, and Move Gladiatorial Combat while heart rate, ventilation, and oxygen consumption were measured. There were no differences in heart rate (116.0 ± 18.3 vs. 119.3 ± 17.6 vs. 120.1 ± 17.6 beats/min), oxygen consumption (9.2 ± 3.0 vs. 10.6 ± 2.4 vs. 9.6 ± 2.4 ml/kg/min), or minute ventilation (18.9 ± 5.7 vs. 20.8 ± 8.0 vs. 19.7 ± 6.4 L/min) when playing Wii boxing, Kinect boxing, or Move Gladiatorial Combat (respectively). Playing Nintendo Wii Boxing, XBOX Kinect Boxing, and Sony PlayStation Move Gladiatorial Combat all increase heart rate, oxygen consumption, and ventilation above resting levels but there were no significant differences between gaming systems. Overall, playing a "physically active" home video game system does not meet the minimal threshold for moderate intensity physical activity, regardless of gaming system.

  8. Effects of metal contamination in situ on osmoregulation and oxygen consumption in the mudflat fiddler crab Uca rapax (Ocypodidae, Brachyura).

    Science.gov (United States)

    Capparelli, Mariana V; Abessa, Denis M; McNamara, John C

    2016-01-01

    The contamination of estuaries by metals can impose additional stresses on estuarine species, which may exhibit a limited capability to adjust their regulatory processes and maintain physiological homeostasis. The mudflat fiddler crab Uca rapax is a typical estuarine crab, abundant in both pristine and contaminated areas along the Atlantic coast of Brazil. This study evaluates osmotic and ionic regulatory ability and gill Na(+)/K(+)-ATPase activity in different salinities (Rio Itapanhaú, Bertioga>Picinguaba, Ubatuba [pristine reference site]). Our findings show that the contamination of U. rapax by metals in situ leads to bioaccumulation and induces biochemical and physiological changes compared to crabs from the pristine locality. U. rapax from the contaminated sites exhibit stronger hyper- and hypo-osmotic regulatory abilities and show greater gill Na(+)/K(+)-ATPase activities than crabs from the pristine site, revealing that the underlying biochemical machinery can maintain systemic physiological processes functioning well. However, oxygen consumption, particularly at elevated temperatures, decreases in crabs showing high bioaccumulation titers but increases in crabs with low/moderate bioaccumulation levels. These data show that U. rapax chronically contaminated in situ exhibits compensatory biochemical and physiological adjustments, and reveal the importance of studies on organisms exposed to metals in situ, particularly estuarine invertebrates subject to frequent changes in natural environmental parameters like salinity and temperature. Copyright © 2016. Published by Elsevier Inc.

  9. Concurrent validity of the PAM accelerometer relative to the MTI Actigraph using oxygen consumption as a reference.

    Science.gov (United States)

    Slootmaker, S M; Chin A Paw, M J M; Schuit, A J; van Mechelen, W; Koppes, L L J

    2009-02-01

    The purpose of this study was to examine the concurrent validity of the Personal Activity Monitor (PAM) accelerometer relative to the Actigraph accelerometer using oxygen consumption as a reference, and to assess the test-retest reliability of the PAM. Thirty-two fit, normal weight adults (aged 21-54) performed two activities, treadmill walking and stair walking, while wearing the PAM, the Actigraph and the Cosmed K4b(2). Correlation coefficients and agreement in absolute energy expenditure (EE) levels between PAM, Actigraph and Cosmed were calculated. The test-retest reliability was examined among 296 PAM's using a laboratory shaker. Intraclass correlation coefficients (ICC) and coefficient of variation (CV) were determined. Correlations for treadmill walking and stair walking, respectively, were r(2)=0.95 and r(2)=0.65 for PAM with Actigraph, r(2)=0.82 and r(2)=0.93 for PAM with VO(2) and r(2)=0.64 and 0.74 for Actigraph with VO(2). Both the PAM and Actigraph underestimated EE during treadmill and stair walking by a substantial amount. The test-retest reliability of the PAM was high [ICC=0.80; 95% confidence interval (CI) (0.28;0.92) and intra-CV=1.5%]. The PAM and Actigraph accelerometer are comparable in assessing bodily movement during treadmill and stair walking. The PAM is a valid device to rank subjects in EE and can be useful in collecting objective data to monitor habitual physical activity.

  10. Excess postexercise oxygen consumption is unaffected by the resistance and aerobic exercise order in an exercise session.

    Science.gov (United States)

    Oliveira, Norton L; Oliveira, Jose

    2011-10-01

    The main purpose of this study was to compare the magnitude and duration of excess postexercise oxygen consumption (EPOC) after 2 exercise sessions with different exercise mode orders, resistance followed by aerobic exercise (R-A); aerobic by resistance exercise (A-R). Seven young men (19.6 ± 1.4 years) randomly underwent the 2 sessions. Aerobic exercise was performed on a treadmill for 30 minutes (80-85% of reserve heart rate). Resistance exercise consisted of 3 sets of 10 repetition maximum on 5 exercises. Previous to the exercise sessions, V(O2), heart rate, V(CO2), and respiratory exchange rate (RER) were measured for 15 minutes and again during recovery from exercise for 60 minutes. The EPOC magnitude was not significantly different between R-A (5.17 ± 2.26 L) and A-R (5.23 ± 2.48 L). Throughout the recovery period (60 minutes), V(O2) and HR values were significantly higher than those observed in the pre-exercise period (p better to start a training session.

  11. A procedure for the measurement of Oxygen Consumption Rates (OCRs) in red wines and some observations about the influence of wine initial chemical composition.

    Science.gov (United States)

    Marrufo-Curtido, Almudena; Carrascón, Vanesa; Bueno, Mónica; Ferreira, Vicente; Escudero, Ana

    2018-05-15

    The rates at which wine consumes oxygen are important technological parameters for whose measurement there are not accepted procedures. In this work, volumes of 8 wines are contacted with controlled volumes of air in air-tight tubes containing oxygen-sensors and are further agitated at 25 °C until O 2 consumption is complete. Three exposure levels of O 2 were used: low (10 mg/L) and medium or high (18 or 32 mg/L plus the required amount to oxidize all wine SO 2 ). In each oxygen level, 2-4 independent segments following pseudo-first order kinetics were identified, plus an initial segment at which wine consumed O 2 very fast. Overall, multivariate data techniques identify six different Oxygen-Consumption-Rates (OCRs) as required to completely define wine O 2 consumption. Except the last one, all could be modeled from the wine initial chemical composition. Total acetaldehyde, Mn, Cu/Fe, blue and red pigments and gallic acid seem to be essential to determine these OCRs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. CLA supplementation and aerobic exercise lower blood triacylglycerol, but have no effect on peak oxygen uptake or cardiorespiratory fatigue thresholds.

    Science.gov (United States)

    Jenkins, Nathaniel D M; Buckner, Samuel L; Cochrane, Kristen C; Bergstrom, Haley C; Goldsmith, Jacob A; Weir, Joseph P; Housh, Terry J; Cramer, Joel T

    2014-09-01

    This study examined the effects of 6 weeks of conjugated linoleic acid (CLA) supplementation and moderate aerobic exercise on peak oxygen uptake (VO2 peak), the gas exchange threshold (GET), the respiratory compensation point (RCP), and serum concentrations of cholesterol, triacylglycerol, and glucose in humans. Thirty-four untrained to moderately trained men (mean ± SD; age = 21.5 ± 2.8 years; mass = 77.2 ± 9.5 kg) completed this double-blind, placebo controlled study and were randomly assigned to either a CLA (Clarinol A-80; n = 18) or placebo (PLA; sunflower oil; n = 16) group. Prior to and following 6 weeks of aerobic training (50% VO2 peak for 30 min, twice per week) and supplementation (5.63 g of total CLA isomers [of which 2.67 g was c9, t11 and 2.67 g was t10, c12] or 7.35 g high oleic sunflower oil per day), each participant completed an incremental cycle ergometer test to exhaustion to determine their [Formula: see text] peak, GET, and RCP and fasted blood draws were performed to measure serum concentrations of cholesterol, triacylglycerol, and glucose. Serum triacylglycerol concentrations were lower (p interactions (p 0.05) between the CLA and PLA groups. GET and RCP increased (p < 0.05) from pre- to post-training for both the CLA and PLA groups. Overall, these data suggested that CLA and aerobic exercise may have synergistic, blood triacylglycerol lowering effects, although CLA may be ineffective for enhancing aerobic exercise performance in conjunction with a 6-week aerobic exercise training program in college-age men.

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

    Directory of Open Access Journals (Sweden)

    Luis F. Del Castillo

    2015-01-01

    Conclusion: Present results are relevant for the calculation on the partial pressure of oxygen, available at different depths into the corneal tissue behind contact lenses of different oxygen transmissibility.

  14. Cellular respiration, oxygen consumption, and trade-offs of the jellyfish Cassiopea sp. in response to temperature change

    Science.gov (United States)

    Aljbour, Samir M.; Zimmer, Martin; Kunzmann, Andreas

    2017-10-01

    Pelagic jellyfish blooms are increasing worldwide as a potential response to climate-change. However, virtually nothing is known about physiological responses of jellyfish to e.g. sudden changes in water temperature due to extreme weather events. When confronted with a sudden decrease or increase in water temperature by 6 °C, medusae of Cassiopea sp. exhibited a strong response in locomotor activity (i.e., bell pulsation increased and decreased by ca. 37 and 46% in hot and cold acute (2 h) treatments, respectively) relative to control. Although medusae significantly gained in body mass (wet weight) upon chronic (2 weeks) heat treatment, their body size (e.g., bell diameter) did not change over this time interval. In contrast, chronic cold treatment resulted in both significant shrinking (reduced diameter) and mass loss. Measurements of mitochondrial electron transport system (ETS) activities and rate of respiratory oxygen uptake (MO2) are good estimates of energy consumption and the potential aerobic metabolic rates of an organism. While both acute treatments significantly increased ETS-activities, acclimation over two weeks resulted in a drop in activities to the control levels. Whereas acute heat treatment significantly increased MO2, chronic exposure resulted in significant MO2 decrease compared to control; however no changes in MO2 could be observed in both acute and chronic cold treatments. Overall these results suggest an enhanced growth in response to global warming, whereas low temperatures may set the limits for successful invasion of Cassiopea into colder water bodies. Our results provide a framework for understanding the physiological tolerance of Cassiopea under possible future climate changes.

  15. Simultaneous evaluation of substrate-dependent oxygen consumption rates and mitochondrial membrane potential by TMRM and safranin in cortical mitochondria.

    Science.gov (United States)

    Chowdhury, Subir Roy; Djordjevic, Jelena; Albensi, Benedict C; Fernyhough, Paul

    2015-12-08

    Mitochondrial membrane potential (mtMP) is critical for maintaining the physiological function of the respiratory chain to generate ATP. The present study characterized the inter-relationship between mtMP, using safranin and tetramethyl rhodamine methyl ester (TMRM), and mitochondrial respiratory activity and established a protocol for functional analysis of mitochondrial bioenergetics in a multi-sensor system. Coupled respiration was decreased by 27 and 30-35% in the presence of TMRM and safranin respectively. Maximal respiration was higher than coupled with Complex I- and II-linked substrates in the presence of both dyes. Safranin showed decreased maximal respiration at a higher concentration of carbonyl cyanide-4-(trifluoromethoxy)phenylhydrazone (FCCP) compared with TMRM. FCCP titration revealed that maximal respiration in the presence of glutamate and malate was not sustainable at higher FCCP concentrations as compared with pyruvate and malate. Oxygen consumption rate (OCR) and mtMP in response to mitochondrial substrates were higher in isolated mitochondria compared with tissue homogenates. Safranin exhibited higher sensitivity to changes in mtMP than TMRM. This multi-sensor system measured mitochondrial parameters in the brain of transgenic mice that model Alzheimer's disease (AD), because mitochondrial dysfunction is believed to be a primary event in the pathogenesis of AD. The coupled and maximal respiration of electron transport chain were decreased in the cortex of AD mice along with the mtMP compared with age-matched controls. Overall, these data demonstrate that safranin and TMRM are suitable for the simultaneous evaluation of mtMP and respiratory chain activity using isolated mitochondria and tissue homogenate. However, certain care should be taken concerning the selection of appropriate substrates and dyes for specific experimental circumstances. © 2016 Authors.

  16. High- and moderate-intensity aerobic exercise and excess post-exercise oxygen consumption in men with metabolic syndrome.

    Science.gov (United States)

    Larsen, I; Welde, B; Martins, C; Tjønna, A E

    2014-06-01

    Physical activity is central in prevention and treatment of metabolic syndrome. High-intensity aerobic exercise can induce larger energy expenditure per unit of time compared with moderate-intensity exercise. Furthermore, it may induce larger energy expenditure at post-exercise recovery. The aim of this study is to compare the excess post-exercise oxygen consumption (EPOC) in three different aerobic exercise sessions in men with metabolic syndrome. Seven men (age: 56.7 ± 10.8) with metabolic syndrome participated in this crossover study. The sessions consisted of one aerobic interval (1-AIT), four aerobic intervals (4-AIT), and 47-min continuous moderate exercise (CME) on separate days, with at least 48 h between each test day. Resting metabolic rate (RMR) was measured pre-exercise and used as baseline value. EPOC was measured until baseline metabolic rate was re-established. An increase in O2 uptake lasting for 70.4 ± 24.8 min (4-AIT), 35.9 ± 17.3 min (1-AIT), and 45.6 ± 17.3 min (CME) was observed. EPOC were 2.9 ± 1.7 L O2 (4-AIT), 1.3 ±  .1 L O2 (1-AIT), and 1.4 ± 1.1 L O2 (CME). There were significant differences (P exercise intensity has a significant positive effect on EPOC in men with metabolic syndrome. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  17. Temperature effect on behaviour, oxygen consumption, ammonia excretion and tolerance limit of the post larvae of shrimp Penaeus indicus.

    Science.gov (United States)

    Krishnamoorthy, R; Mohamed, E H Syed; Rao, T Subba; Venugopalanj, V P; Hameed, P Shahul

    2008-01-01

    The present study has been carried out to know the effect of temperature on behaviour, equilibrium loss and tolerance limit of the post larvae of shrimp Penaeus indicus. The experimental temperatures were selected based on the thermal tolerance limit. The experiments were conducted at a specific temperature for duration of 48 hr. The thermal tolerance experiments were conducted in two ways: in direct exposure and in gradually increasing temperature. The upper and lower lethal temperatures for the post larvae of shrimp P. indicus were 43.5 degrees C and 8 degrees C respectively. During tolerance experiment, no mortality was observed at 33 degrees C and 35 degrees C. But at 38 degrees C with gradual increase in temperature, 30% loss of equilibrium and mortality were recorded in 24.31 hrs and 25.07 hrs, and the remaining 70% were alive. On the contrary, when the post larvae of shrimps were directly exposed to 38 degrees C, almost 80% loss of equilibrium and mortality were recorded in 30.22 hrs and 30.40 hrs, remaining 20% were alive. At 40 degrees C with gradual increase in temperature, 100% loss of equilibrium and mortality were recorded in 25.32 hrs and 25.56 hrs. On the other hand, when the post larvae of shrimps were directly exposed to 40 degrees C, 100% loss of equilibrium was observed in 0.37 hrs and mortality in 1.40 hrs. These behavioral responses include an elevated temperature of 12 degrees C, surfacing, dashing against glass wall, jumping out of the water, etc. In general, the rate of oxygen consumption and ammonia excretion was found to enhance with increasing temperature. In the present study, it was found that gradual increase in temperature favours the shellfish population to escape from the thermal exposure as compared to direct exposure.

  18. Acute effect of ivabradine on heart rate and myocardial oxygen consumption in dogs with asymptomatic mitral valve degeneration.

    Science.gov (United States)

    Pirintr, Prapawadee; Limprasutr, Vudhiporn; Saengklub, Nakkawee; Pavinadol, Parnpradub; Yapao, Napat; Limvanicharat, Natthakarn; Kuecharoen, Hathaisiri; Kijtawornrat, Anusak

    2018-05-14

    Degenerative mitral valve disease (DMVD) is a common cardiac disease in geriatric dogs characterized by the degeneration of the mitral valve, leading to decreased cardiac output and activation of the sympathetic and renin-angiotensin-aldosterone system. This disease results in an increased resting heart rate (HR) and myocardial oxygen consumption (MVO 2 ). A recent publication demonstrated that dogs with asymptomatic DMVD had a significantly higher HR and systemic blood pressure (BP) than age-matched control dogs. This higher HR will eventually contribute to increased MVO 2 . This study aimed to determine the effects of a single oral dose of ivabradine on the HR, MVO 2 as assessed by the rate-pressure product, and BP in dogs with asymptomatic DMVD. Seven beagles with naturally occurring DMVD were instrumented by the Holter recorder and an oscillometric device to measure electrocardiogram and BP for 24 and 12 h, respectively. Each dog was randomly subjected to receive either placebo or ivabradine (0.5, 1.0 and 2.0 mg/kg). The results revealed that oral administration of ivabradine significantly decreased the HR and rate-pressure product in a dose-dependent manner without adverse effects. The highest dose of 2.0 mg/kg significantly reduced systolic and mean BP. Therefore, the findings imply that a single oral ivabradine administration at a dose of 1.0 mg/kg is suitable for dogs with asymptomatic DMVD to reduce the HR and MVO 2 without marked effects on BP. This may potentially make ivabradine promising for management of an elevated HR in DMVD dogs.

  19. Influence of different production strategies on the stability of color, oxygen consumption and metmyoglobin reducing activity of meat from Ningxia Tan sheep.

    Science.gov (United States)

    Gao, Xiaoguang; Wang, Zhenyu; Miao, Jing; Xie, Li; Dai, Yan; Li, Xingmin; Chen, Yong; Luo, Hailing; Dai, Ruitong

    2014-02-01

    Fifty male Ningxia Tan sheep were randomly divided into five groups (10 per group). Different feeding strategies were applied to each group for 120 days prior to slaughter. The sheep belong to five groups were pastured for 0 h (feedlot-fed), 2h, 4h, 8h, 12h per day on a natural grazing ground, respectively. M. semitendinosus muscle from Tan sheep was obtained after slaughter. Instrumental color, pH values, oxygen consumption rate, metmyoglobin reducing activity and relative metmyoglobin percentages were analyzed after 1, 3, 5, 7 and 9 days of refrigerated storage. Long-term daily grazing and herbage-based diet were conducive to maintain a lower oxygen consumption rate, higher metmyoglobin reducing activity and lower metmyoglobin accumulation. The combination of pasture-fed and feedlot-fed was conducive to weight gain, and at the same time, increased the color stability of the meat from Ningxia Tan sheep. © 2013.

  20. Energy savings in sea bass swimming in a school: measurements of tail beat frequency and oxygen consumption at different swimming speeds

    DEFF Research Database (Denmark)

    Herskin, J; Steffensen, JF

    1998-01-01

    Tail beat frequency of sea bass, Dicentrarchus labrax (L.) (23.5 ± 0·5 cm, LT), swimming at the front of a school was significantly higher than when swimming at the rear, for all water velocities tested from 14·8 to 32 cm s-1. The logarithm of oxygen consumption rate, and the tail beat frequency...... of solitary swimming sea bass (28·8 ± 0·4 cm, LT), were each correlated linearly with swimming speed, and also with one another. The tail beat frequency of individual fish was 9-14% lower when at the rear of a school than when at the front, corresponding to a 9-23% reduction in oxygen consumption rate....

  1. Wii, Kinect, and Move. Heart Rate, Oxygen Consumption, Energy Expenditure, and Ventilation due to Different Physically Active Video Game Systems in College Students

    OpenAIRE

    SCHEER, KRISTA S.; SIEBRANT, SARAH M.; BROWN, GREGORY A.; SHAW, BRANDON S.; SHAW, INA

    2014-01-01

    Nintendo Wii, Sony Playstation Move, and Microsoft XBOX Kinect are home video gaming systems that involve player movement to control on-screen game play. Numerous investigations have demonstrated that playing Wii is moderate physical activity at best, but Move and Kinect have not been as thoroughly investigated. The purpose of this study was to compare heart rate, oxygen consumption, and ventilation while playing the games Wii Boxing, Kinect Boxing, and Move Gladiatorial Combat. Heart rate, o...

  2. Bio-filtration capacity, oxygen consumption and ammonium excretion of Dosinia ponderosa and Chione gnidia (Veneroida: Veneridae) from areas impacted and non-impacted by shrimp aquaculture effluents.

    Science.gov (United States)

    Ramos-Corella, Karime; Martínez-Córdova, Luis Rafael; Enríquez-Ocaña, Luis Fernando; Miranda-Baeza, Anselmo; López-Elías, José Antonio

    2014-09-01

    Mollusks are some of the most important, abundant and diverse organisms inhabiting not only aquatic ecosystems, but also terrestrial environments. Recently, they have been used for bioremediation of aquaculture effluents; nevertheless, for that purpose it is necessary to analyze the capacity of a particular species. In this context, an experimental investigation was developed to evaluate the performance of two bivalves C. gnidia and D. ponderosa, collected from areas with or without shrimp aquaculture effluents. For this, the filtration capacity (as clearance rate) as well as the oxygen consumption and ammonia excretion rates were measured following standard methods. The clearance rate was significantly higher for D. ponderosa from impacted areas, when com- pared to C. gnidia, from both areas. Contrarily, the oxygen consumption was greater for C. gnidia from impacted areas compared to D. ponderosa from both areas. The same tendency was observed for the ammonia excretion with the highest rates observed for C. gnidia from impacted areas, whereas no differences were observed among D. ponderosa from both areas. The results suggest that both species developed different strategies to thrive and survive under the impacted conditions; D. ponderosa improved its filtration efficiency, while C. gnidia modified its oxygen consumption and ammonia excretion. We concluded that both species, and particularly D. ponderosa, can be used for bioremediation purposes.

  3. Bio-filtration capacity, oxygen consumption and ammonium excretion of Dosinia ponderosa and Chione gnidia (Veneroida: Veneridae from areas impacted and non-impacted by shrimp aquaculture effluents

    Directory of Open Access Journals (Sweden)

    Karime Ramos-Corella

    2014-09-01

    Full Text Available Mollusks are some of the most important, abundant and diverse organisms inhabiting not only aquatic ecosystems, but also terrestrial environments. Recently, they have been used for bioremediation of aquaculture effluents; nevertheless, for that purpose it is necessary to analyze the capacity of a particular species. In this context, an experimental investigation was developed to evaluate the performance of two bivalves C. gnidia and D. ponderosa, collected from areas with or without shrimp aquaculture effluents. For this, the filtration capacity (as clearance rate as well as the oxygen consumption and ammonia excretion rates were measured following standard methods. The clearance rate was significantly higher for D. ponderosa from impacted areas, when com- pared to C. gnidia, from both areas. Contrarily, the oxygen consumption was greater for C. gnidia from impacted areas compared to D. ponderosa from both areas. The same tendency was observed for the ammonia excretion with the highest rates observed for C. gnidia from impacted areas, whereas no differences were observed among D. ponderosa from both areas. The results suggest that both species developed different strategies to thrive and survive under the impacted conditions; D. ponderosa improved its filtration efficiency, while C. gnidia modified its oxygen consumption and ammonia excretion. We concluded that both species, and particularly D. ponderosa, can be used for bioremediation purposes.

  4. Duration of effects of acute environmental changes on food anticipatory behaviour, feed intake, oxygen consumption, and cortisol release in Atlantic salmon parr.

    Science.gov (United States)

    Folkedal, Ole; Torgersen, Thomas; Olsen, Rolf Erik; Fernö, Anders; Nilsson, Jonatan; Oppedal, Frode; Stien, Lars H; Kristiansen, Tore S

    2012-01-18

    We compared behavioural and physiological responses and recovery time after different acute environmental challenges in groups of salmon parr. The fish were prior to the study conditioned to a flashing light signalling arrival of food 30 s later to study if the strength of Pavlovian conditioned food anticipatory behaviour can be used to assess how salmon parr cope with various challenges. The effect on anticipatory behaviour was compared to the effect on feed intake and physiological responses of oxygen hyper-consumption and cortisol excretion. The challenges were temperature fluctuation (6.5C° over 4 h), hyperoxia (up to 380% O(2) saturation over 4 h), and intense chasing for 10 min. Cortisol excretion was only elevated after hyperoxia and chasing, and returned to baseline levels after around 3 h or less. Oxygen hyper-consumption persisted for even shorter periods. Feed intake was reduced the first feeding after all challenges and recovered within 3 h after temperature and hyperoxia, but was reduced for days after chasing. Food anticipatory behaviour was reduced for a longer period than feed intake after hyperoxia and was low at least 6 h after chasing. Our findings suggest that a recovery of challenged Atlantic salmon parr to baseline levels of cortisol excretion and oxygen consumption does not mean full recovery of all psychological and physiological effects of environmental challenges, and emphasise the need for measuring several factors including behavioural parameters when assessing fish welfare. Copyright © 2011 Elsevier Inc. All rights reserved.

  5. Graded Exercise Testing in a Pediatric Weight Management Center: The DeVos Protocol.

    Science.gov (United States)

    Eisenmann, Joey C; Guseman, Emily Hill; Morrison, Kyle; Tucker, Jared; Smith, Lucie; Stratbucker, William

    2015-12-01

    In this article, we describe a protocol used to test the functional capacity of the obese pediatric patient and describe the peak oxygen consumption (VO2peak) of patients seeking treatment at a pediatric weight management center. One hundred eleven (mean age, 12.5 ± 3.0 years) patients performed a multistage exercise test on a treadmill, of which 90 (81%) met end-test criteria and provided valid VO2peak data. Peak VO2 was expressed: (1) in absolute terms (L·min(-1)); (2) as the ratio of the volume of oxygen consumed per minute relative to total body mass (mL·kg(-1)·min(-1)); and (3) as the ratio of the volume of oxygen consumed per minute relative to fat-free mass (mL·FFM·kg(-1)·min(-1)). Mean BMI z-score was 2.4 ± 0.3 and the mean percent body fat was 36.5 ± 9.7%. Absolute VO2peak (L·min(-1)) was significantly different between sexes; however, relative values were similar between sexes. Mean VO2peak was 25.7 ± 4.8 mL·kg(-1)·min(-1) with a range of 13.5-36.7 mL·kg(-1)·min(-1). Obese youth seeking treatment at a stage 3 pediatric weight management center exhibit low VO2peak. The protocol outlined here should serve as a model for similar programs interested in the submaximal and peak responses to exercise in obese pediatric patients.

  6. Respiratory, cardiovascular and metabolic responses during different modes of overground bionic ambulation in persons with motor-incomplete spinal cord injury: A case series

    Directory of Open Access Journals (Sweden)

    Jochen Kressler

    2017-09-01

    Full Text Available Objective: To investigate the effects of overground bionic ambulation with variable assistance on cardiorespiratory and metabolic responses in persons with motor-incomplete spinal cord injury. Design: Case series. Subjects: Four participants with chronic, motor-incomplete spinal cord injury. Methods: Subjects completed a maximal graded exercise test on an arm-ergometer and 3 6-min bouts of overground bionic ambulation using different modes of assistance, i.e. Maximal, Adaptive, Fixed. Cardiorespiratory (oxygen consumption and metabolic (caloric expenditure and substrate utilization measures were taken using a mobile metabolic cart at each overground bionic ambulation assistance. Results: Cardiorespiratory responses ranged from low (24% VO2peak for the least impaired and fittest individual to supramaximal (124% VO2peak for the participant with the largest impairments and the lowest level of fitness. Different overground bionic ambulation assistive modes elicited small (3–8% VO2peak differences in cardiorespiratory responses for 3 participants. One participant had a large (28% VO2peak difference in cardiorespiratory responses to different modes of overground bionic ambulation. Metabolic responses mostly tracked closely with cardiorespiratory responses. Total energy expenditure ranged from 1.39 to 7.17 kcal/min. Fat oxidation ranged from 0.00 to 0.17 g/min across participants and different overground bionic ambulation modes. Conclusion: Overground bionic ambulation with variable assistance can substantially increase cardiorespiratory and metabolic responses; however, these responses vary widely across participants and overground bionic ambulation modes.

  7. Demonstration of the need for cardiovascular and pulmonary normative data for cancer survivors.

    Science.gov (United States)

    Schneider, C M; Repka, C P; Brown, J M; Lalonde, T L; Dallow, K T; Barlow, C E; Hayward, R

    2014-12-01

    Despite evidence that cancer and its treatments severely reduce cardiorespiratory fitness (CRF), normative data for cancer survivors do not exist. The present study identifies age and gender-specific CRF distributions in a cancer population. The use of cancer-specific normative CRF data may help stratify initial fitness status and assess improvements in response to exercise interventions in cancer survivors. Data from 703 cancer survivors were analyzed for this study. Quintiles were compiled for peak oxygen consumption (VO2peak), forced vital capacity (FVC), and forced expiratory volume (FEV1) for males and females in 5 age groups (19-39, 40-49, 50-59, 60-69, and ≥70 years of age). VO2peak values for the cancer population were significantly lower than the general US population. The cancer population average in each age group fell within the "very poor" classification of VO2peak values for the general population. FVC values in the cancer population were similar to the general population. Cancer survivors had very low age group-specific VO2peak values compared to the apparently healthy general US population. Previously, CRF values of cancer survivors were compared to normative values for the apparently healthy general population, which yielded imprecise classifications of initial fitness and changes in fitness, resulting in patient discouragement. © Georg Thieme Verlag KG Stuttgart · New York.

  8. Maximal exercise test is a useful method for physical capacity and oxygen consumption determination in streptozotocin-diabetic rats

    Directory of Open Access Journals (Sweden)

    Irigoyen Maria-Cláudia

    2007-12-01

    Full Text Available Abstract Background The aim of the present study was to investigate the relationship between speed during maximum exercise test (ET and oxygen consumption (VO2 in control and STZ-diabetic rats, in order to provide a useful method to determine exercise capacity and prescription in researches involving STZ-diabetic rats. Methods Male Wistar rats were divided into two groups: control (CG, n = 10 and diabetic (DG, n = 8. The animals were submitted to ET on treadmill with simultaneous gas analysis through open respirometry system. ET and VO2 were assessed 60 days after diabetes induction (STZ, 50 mg/Kg. Results VO2 maximum was reduced in STZ-diabetic rats (72.5 ± 1 mL/Kg/min-1 compared to CG rats (81.1 ± 1 mL/Kg/min-1. There were positive correlations between ET speed and VO2 (r = 0.87 for CG and r = 0.8 for DG, as well as between ET speed and VO2 reserve (r = 0.77 for CG and r = 0.7 for DG. Positive correlations were also obtained between measured VO2 and VO2 predicted values (r = 0.81 for CG and r = 0.75 for DG by linear regression equations to CG (VO2 = 1.54 * ET speed + 52.34 and DG (VO2 = 1.16 * ET speed + 51.99. Moreover, we observed that 60% of ET speed corresponded to 72 and 75% of VO2 reserve for CG and DG, respectively. The maximum ET speed was also correlated with VO2 maximum for both groups (CG: r = 0.7 and DG: r = 0.7. Conclusion These results suggest that: a VO2 and VO2 reserve can be estimated using linear regression equations obtained from correlations with ET speed for each studied group; b exercise training can be prescribed based on ET in control and diabetic-STZ rats; c physical capacity can be determined by ET. Therefore, ET, which involves a relatively simple methodology and low cost, can be used as an indicator of cardio-respiratory capacity in future studies that investigate the physiological effect of acute or chronic exercise in control and STZ-diabetic male rats.

  9. Maximal exercise test is a useful method for physical capacity and oxygen consumption determination in streptozotocin-diabetic rats

    Science.gov (United States)

    Rodrigues, Bruno; Figueroa, Diego M; Mostarda, Cristiano T; Heeren, Marcelo V; Irigoyen, Maria-Cláudia; De Angelis, Kátia

    2007-01-01

    Background The aim of the present study was to investigate the relationship between speed during maximum exercise test (ET) and oxygen consumption (VO2) in control and STZ-diabetic rats, in order to provide a useful method to determine exercise capacity and prescription in researches involving STZ-diabetic rats. Methods Male Wistar rats were divided into two groups: control (CG, n = 10) and diabetic (DG, n = 8). The animals were submitted to ET on treadmill with simultaneous gas analysis through open respirometry system. ET and VO2 were assessed 60 days after diabetes induction (STZ, 50 mg/Kg). Results VO2 maximum was reduced in STZ-diabetic rats (72.5 ± 1 mL/Kg/min-1) compared to CG rats (81.1 ± 1 mL/Kg/min-1). There were positive correlations between ET speed and VO2 (r = 0.87 for CG and r = 0.8 for DG), as well as between ET speed and VO2 reserve (r = 0.77 for CG and r = 0.7 for DG). Positive correlations were also obtained between measured VO2 and VO2 predicted values (r = 0.81 for CG and r = 0.75 for DG) by linear regression equations to CG (VO2 = 1.54 * ET speed + 52.34) and DG (VO2 = 1.16 * ET speed + 51.99). Moreover, we observed that 60% of ET speed corresponded to 72 and 75% of VO2 reserve for CG and DG, respectively. The maximum ET speed was also correlated with VO2 maximum for both groups (CG: r = 0.7 and DG: r = 0.7). Conclusion These results suggest that: a) VO2 and VO2 reserve can be estimated using linear regression equations obtained from correlations with ET speed for each studied group; b) exercise training can be prescribed based on ET in control and diabetic-STZ rats; c) physical capacity can be determined by ET. Therefore, ET, which involves a relatively simple methodology and low cost, can be used as an indicator of cardio-respiratory capacity in future studies that investigate the physiological effect of acute or chronic exercise in control and STZ-diabetic male rats. PMID:18078520

  10. Differential Effects of Temperature on Oxygen Consumption and Branchial Fluxes of Urea, Ammonia, and Water in the Dogfish Shark (Squalus acanthias suckleyi).

    Science.gov (United States)

    Giacomin, Marina; Schulte, Patricia M; Wood, Chris M

    Environmental temperature can greatly influence the homeostasis of ectotherms through its effects on biochemical reactions and whole-animal physiology. Elasmobranchs tend to be N limited and are osmoconformers, retaining ammonia and urea-N at the gills and using the latter as a key osmolyte to maintain high blood osmolality. However, the effects of temperature on these key processes remain largely unknown. We evaluated the effects of acute exposure to different temperatures (7°, 12°, 15°, 18°, 22°C) on oxygen consumption, ammonia, urea-N, and diffusive water fluxes at the gills of Squalus acanthias suckleyi. We hypothesized that as metabolic demand for oxygen increased with temperature, the fluxes of ammonia, urea-N, and 3 H 2 O at the gills would increase in parallel with those of oxygen. Oxygen consumption (overall [Formula: see text] from 7.5° to 22°C) and water fluxes (overall [Formula: see text]) responded to increases in temperature in a similar, almost linear, manner. Ammonia-N efflux rates varied the most, increasing almost 15-fold from 7.5° to 22°C ([Formula: see text]). Urea-N efflux was tightly conserved over the 7.5°-15°C range ([Formula: see text]) but increased greatly at higher temperatures, yielding an overall [Formula: see text]. These differences likely reflect differences in the transport pathways for the four moieties. They also suggest the failure of urea-N- and ammonia-N-conserving mechanisms at the gill above 15°C. Hyperoxia did not alleviate the effects of high temperature. Indeed, urea-N and ammonia-N effluxes were dramatically increased when animals were exposed to high temperatures in the presence of hyperoxia, suggesting that high partial pressure of oxygen may have caused oxidative damage to gill epithelial membranes.

  11. Oxygen and coke oven gas (COG) consumption optimization at hot stove of Usiminas blast furnace 3; Otimizacao do consumo de oxigenio e GCO nos regeneradores do alto forno 3 da Usiminas

    Energy Technology Data Exchange (ETDEWEB)

    Cervino, Marco Antonio; Bastos, Moises Hofer [Usiminas, Ipatinga, MG (Brazil)

    2001-07-01

    This paper presents the model developed for determination of the correlation between oxygen and coke oven gas (COG) consumption in the hot stove at Usiminas blast furnace 3, the applicability and results obtained. (author)

  12. High intensity interval training improves VO2peak, maximal lactate production, time trial and competition performance in 9-11 year old swimmers

    OpenAIRE

    Sperlich, Billy; Zinner, Christoph; Helleman, Ilka; Kjendlie, Per-Ludvik; Holmberg, H. C.; Mester, Joachim

    2010-01-01

    Open Access - This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the source is credited. Training volume in swimming is usually very high when compared to the relatively short competition time. High-intensity interval training (HIIT) has been demonstrated to improve performance in a relatively short training period. The main purpose of the present s...

  13. Diurnal dynamics of oxygen and carbon dioxide concentrations in shoots and rhizomes of a perennial in a constructed wetland indicate down-regulation of below ground oxygen consumption

    Czech Academy of Sciences Publication Activity Database

    Fausser, A. C.; Dušek, Jiří; Čížková, Hana; Kazda, M.

    2016-01-01

    Roč. 8, JUL (2016), č. článku plw025. ISSN 2041-2851 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073; GA MŠk(CZ) LM2010007 Institutional support: RVO:86652079 Keywords : typha-latifolia l * internal gas-transport * phragmites-australis * convective throughflow * pressurized ventilation * angustifolia l * ex steud * roots * flow * respiration * Aeration * constructed wetland * in-situ field study * internal carbon dioxide * internal oxygen dynamics * Phragmites australis Subject RIV: EF - Botanics OBOR OECD: Plant sciences, botany Impact factor: 2.238, year: 2016

  14. Aerobic capacity related to cardiac size in young children

    DEFF Research Database (Denmark)

    Dencker, M; Wollmer, P; Karlsson, M

    2013-01-01

    Aerobic capacity, defined as peak oxygen uptake (VO2PEAK), is generally considered to be the best single marker for aerobic fitness. We assessed if VO2PEAK is related to different cardiac dimensions in healthy young children on a population base.......Aerobic capacity, defined as peak oxygen uptake (VO2PEAK), is generally considered to be the best single marker for aerobic fitness. We assessed if VO2PEAK is related to different cardiac dimensions in healthy young children on a population base....

  15. Oxygen consumption remains stable while ammonia excretion is reduced upon short time exposure to high salinity in Macrobrachium acanthurus (Caridae: Palaemonidae, a recent freshwater colonizer

    Directory of Open Access Journals (Sweden)

    Carolina A. Freire

    2017-10-01

    Full Text Available ABSTRACT Palaemonid shrimps occur in the tropical and temperate regions of South America and the Indo-Pacific, in brackish/freshwater habitats, and marine coastal areas. They form a clade that recently (i.e., ~30 mya invaded freshwater, and one included genus, Macrobrachium Bate, 1868, is especially successful in limnic habitats. Adult Macrobrachium acanthurus (Wiegmann, 1836 dwell in coastal freshwaters, have diadromous habit, and need brackish water to develop. Thus, they are widely recognized as euryhaline. Here we test how this species responds to a short-term exposure to increased salinity. We hypothesized that abrupt exposure to high salinity would result in reduced gill ventilation/perfusion and decreased oxygen consumption. Shrimps were subjected to control (0 psu and experimental salinities (10, 20, 30 psu, for four and eight hours (n = 8 in each group. The water in the experimental containers was saturated with oxygen before the beginning of the experiment; aeration was interrupted before placing the shrimp in the experimental container. Dissolved oxygen (DO, ammonia concentration, and pH were measured from the aquaria water, at the start and end of each experiment. After exposure, the shrimp’s hemolymph was sampled for lactate and osmolality assays. Muscle tissue was sampled for hydration content (Muscle Water Content, MWC. Oxygen consumption was not reduced and hemolymph lactate did not increase with increased salinity. The pH of the water decreased with time, under all conditions. Ammonia excretion decreased with increased salinity. Hemolymph osmolality and MWC remained stable at 10 and 20 psu, but osmolality increased (~50% and MWC decreased (~4% at 30 psu. The expected reduction in oxygen consumption was not observed. This shrimp is able to tolerate significant changes in water salt concentrations for a few hours by keeping its metabolism in aerobic mode, and putatively shutting down branchial salt uptake to avoid massive salt

  16. Validation and Refinement of Prediction Models to Estimate Exercise Capacity in Cancer Survivors Using the Steep Ramp Test.

    Science.gov (United States)

    Stuiver, Martijn M; Kampshoff, Caroline S; Persoon, Saskia; Groen, Wim; van Mechelen, Willem; Chinapaw, Mai J M; Brug, Johannes; Nollet, Frans; Kersten, Marie-José; Schep, Goof; Buffart, Laurien M

    2017-11-01

    To further test the validity and clinical usefulness of the steep ramp test (SRT) in estimating exercise tolerance in cancer survivors by external validation and extension of previously published prediction models for peak oxygen consumption (Vo 2peak ) and peak power output (W peak ). Cross-sectional study. Multicenter. Cancer survivors (N=283) in 2 randomized controlled exercise trials. Not applicable. Prediction model accuracy was assessed by intraclass correlation coefficients (ICCs) and limits of agreement (LOA). Multiple linear regression was used for model extension. Clinical performance was judged by the percentage of accurate endurance exercise prescriptions. ICCs of SRT-predicted Vo 2peak and W peak with these values as obtained by the cardiopulmonary exercise test were .61 and .73, respectively, using the previously published prediction models. 95% LOA were ±705mL/min with a bias of 190mL/min for Vo 2peak and ±59W with a bias of 5W for W peak . Modest improvements were obtained by adding body weight and sex to the regression equation for the prediction of Vo 2peak (ICC, .73; 95% LOA, ±608mL/min) and by adding age, height, and sex for the prediction of W peak (ICC, .81; 95% LOA, ±48W). Accuracy of endurance exercise prescription improved from 57% accurate prescriptions to 68% accurate prescriptions with the new prediction model for W peak . Predictions of Vo 2peak and W peak based on the SRT are adequate at the group level, but insufficiently accurate in individual patients. The multivariable prediction model for W peak can be used cautiously (eg, supplemented with a Borg score) to aid endurance exercise prescription. Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  17. Aerobic exercise capacity at long-term follow-up after paediatric allogeneic haematopoietic SCT

    DEFF Research Database (Denmark)

    Mathiesen, S; Uhlving, H H; Buchvald, F

    2014-01-01

    Peak oxygen uptake (VO2peak), a measure of aerobic exercise capacity, predicts mortality and morbidity in healthy and diseased individuals. Our aim was to determine VO2peak years after paediatric allogeneic haematopoietic SCT (HSCT) and to identify associations with baseline patient and donor...... type or GvHD were found. Although causes for reduced VO2peak may be multiple, our findings stress the need to focus on physical activity post HSCT to prevent lifestyle diseases and improve quality of life....

  18. Determination of relative CMRO2 from CBF and BOLD changes: significant increase of oxygen consumption rate during visual stimulation

    DEFF Research Database (Denmark)

    Kim, S.G.; Rostrup, Egill; Larsson, H.B.

    1999-01-01

    signal changes were measured simultaneously using the flow-sensitive alternating inversion recovery (FAIR) technique. During hypercapnia established by an end-tidal CO2 increase of 1.46 kPa, CBF in the visual cortex increased by 47.3 +/- 17.3% (mean +/- SD; n = 9), and deltaR2* was -0.478 +/- 0.147 sec......The blood oxygenation level-dependent (BOLD) effect in functional magnetic resonance imaging depends on at least partial uncoupling between cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) changes. By measuring CBF and BOLD simultaneously, the relative change in CMRO2 can...

  19. High-intensity interval training and β-hydroxy-β-methylbutyric free acid improves aerobic power and metabolic thresholds

    OpenAIRE

    Robinson, Edward H; Stout, Jeffrey R; Miramonti, Amelia A; Fukuda, David H; Wang, Ran; Townsend, Jeremy R; Mangine, Gerald T; Fragala, Maren S; Hoffman, Jay R

    2014-01-01

    Background Previous research combining Calcium β-hydroxy-β-methylbutyrate (CaHMB) and running high-intensity interval training (HIIT) have shown positive effects on aerobic performance measures. The purpose of this study was to examine the effect of β-hydroxy-β-methylbutyric free acid (HMBFA) and cycle ergometry HIIT on maximal oxygen consumption (VO2peak), ventilatory threshold (VT), respiratory compensation point (RCP) and time to exhaustion (Tmax) in college-aged men and women. Methods Thi...

  20. Activity-dependent increases in local oxygen consumption correlate with postsynaptic currents in the mouse cerebellum in vivo

    DEFF Research Database (Denmark)

    Mathiesen, Claus; Caesar, Kirsten; Thomsen, Kirsten Engelund

    2011-01-01

    Evoked neural activity correlates strongly with rises in cerebral metabolic rate of oxygen (CMRO(2)) and cerebral blood flow (CBF). Activity-dependent rises in CMRO(2) fluctuate with ATP turnover due to ion pumping. In vitro studies suggest that increases in cytosolic Ca(2+) stimulate oxidative m...

  1. Activity-dependent increases in local oxygen consumption correlate with post-synaptic currents in the mouse cerebellum in vivo

    DEFF Research Database (Denmark)

    Mathiesen, Claus; Caesar, Kirsten; Thomsen, Kirsten Joan

    2011-01-01

    Evoked neural activity correlates strongly with rises in cerebral metabolic rate of oxygen (CMRO2) and cerebral blood flow. Activity-dependent rises in CMRO2 fluctuate with ATP turnover due to ion pumping. In vitro studies suggest that increases in cytosolic Ca2+ stimulate oxidative metabolism vi...

  2. Hypoxia, but not an electrolyte-imbalanced diet, reduces feed intake, growth and oxygen consumption in rainbow trout (Oncorhynchus mykiss)

    NARCIS (Netherlands)

    Magnoni, Leonardo J.; Eding, Ep; Leguen, Isabelle; Prunet, Patrick; Geurden, Inge; Ozório, Rodrigo O.A.; Schrama, Johan W.

    2018-01-01

    Oxygen limitation and dietary imbalances are key aspects influencing feed intake (FI) and growth performance in cultured fish. This study investigated the combined effects of hypoxia and dietary electrolyte balance on the growth performance, body composition and nutrient utilization in a rainbow

  3. Effects of ozone on adult and aged lung oxygen consumption, glucose metabolism and G6PDH activity

    International Nuclear Information System (INIS)

    Raska-Emery, P.; Balis, J.U.; Montgomery, M.R.

    1991-01-01

    Fischer-344 male adult (4-6 mo) and aged (24-26 mo) rats were exposed to 0-3.0 ppm O 3 for 8h, sacrificed immediately, and O 2 consumption, 1 C 14 -glucose metabolism and G6PDH activity were determined. For O 2 consumption, the exp to 0.5 ppm O 3 produced a stimulation in both age groups. Decrements in O 2 consumption were only evident in aged rats after 1.5 and 3.0 ppm. Glucose metabolism showed a marked difference rats were 40% adult rats. Control values in aged rats were 40% of adults. Exp to 0.5 ppm was stimulatory in adults and aged, while 1.5 and 3.0 pp, decreased glucose metabolism in both groups. No age-related difference in G6PDH activity between control and exposed was seen. However, in both age groups, 0.5 ppm O 3 resulted in a significant increase in activity (33-41%)l 1.5 and 3.0 ppm were without effect. The combined results show a biphasic response of adult and aged lung to severe, acute O 3 exp. One-half ppm O 3 for 8h is stimulatory for all three parameters examined in both age groups. Three ppm O 3 inhibits O 2 consumption and glucose metabolism in both age groups but is ineffective on G6PDH activity

  4. Evaluation of the effects of the metals Cd, Cr, Pb and their mixture on the filtration and oxygen consumption rates in catarina scallop, Argopecten ventricosus juveniles.

    Science.gov (United States)

    Sobrino-Figueroa, Alma S; Cáceres-Martinez, Carlos

    2014-01-01

    In this work, we evaluated the effect of sublethal concentrations ( LC25, LC10 and LC5) of cadmium, chromium, lead, and their mixture on the filtration rate and oxygen consumption rate of Catarina scallop, Argopecten ventricosus (Sowerby, 1842), juveniles, in order to evaluate the use of these biomarkers as a reliable tool in environmental monitoring studies, because these metals have been found at high levels in water and sediments in the Mexican Pacific systems. An inverse dose-response relationship was observed when metal concentration and exposure time increased, the filtration rate and oxygen consumption rate reduced. The physiological responses evaluated in this study were sufficiently sensitive to detect alterations in the organisms at 0.014 mg l(-1) Cd, 0.311 mg l(-1) Cr, 0.125 mg l(-1) Pb and 0.05 mg l(-1) Cd + Cr + Pb at 24 and 72 hrs. Cd showed the most drastic effect. The Catarina scallop juveniles were more sensitive to Cd, Cr and Pb as compared to other bivalves. The biomarkers evaluated are a reliable tool to carry out environmental monitoring studies.

  5. Correlating two-photon excited fluorescence imaging of breast cancer cellular redox state with seahorse flux analysis of normalized cellular oxygen consumption

    Science.gov (United States)

    Hou, Jue; Wright, Heather J.; Chan, Nicole; Tran, Richard; Razorenova, Olga V.; Potma, Eric O.; Tromberg, Bruce J.

    2016-06-01

    Two-photon excited fluorescence (TPEF) imaging of the cellular cofactors nicotinamide adenine dinucleotide and oxidized flavin adenine dinucleotide is widely used to measure cellular metabolism, both in normal and pathological cells and tissues. When dual-wavelength excitation is used, ratiometric TPEF imaging of the intrinsic cofactor fluorescence provides a metabolic index of cells-the "optical redox ratio" (ORR). With increased interest in understanding and controlling cellular metabolism in cancer, there is a need to evaluate the performance of ORR in malignant cells. We compare TPEF metabolic imaging with seahorse flux analysis of cellular oxygen consumption in two different breast cancer cell lines (MCF-7 and MDA-MB-231). We monitor metabolic index in living cells under both normal culture conditions and, for MCF-7, in response to cell respiration inhibitors and uncouplers. We observe a significant correlation between the TPEF-derived ORR and the flux analyzer measurements (R=0.7901, p<0.001). Our results confirm that the ORR is a valid dynamic index of cell metabolism under a range of oxygen consumption conditions relevant for cancer imaging.

  6. Muscle contraction duration and fibre recruitment influence blood flow and oxygen consumption independent of contractile work during steady-state exercise in humans.

    Science.gov (United States)

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

    2012-06-01

    We tested the hypothesis that, among conditions of matched contractile work, shorter contraction durations and greater muscle fibre recruitment result in augmented skeletal muscle blood flow and oxygen consumption ( ) during steady-state exercise in humans. To do so, we measured forearm blood flow (FBF; Doppler ultrasound) during 4 min of rhythmic hand-grip exercise in 24 healthy young adults and calculated forearm oxygen consumption ( ) via blood samples obtained from a catheter placed in retrograde fashion into a deep vein draining the forearm muscle. In protocol 1 (n = 11), subjects performed rhythmic isometric hand-grip exercise at mild and moderate intensities during conditions in which time-tension index (isometric analogue of work) was held constant but contraction duration was manipulated. In this protocol, shorter contraction durations led to greater FBF (184 ± 25 versus 164 ± 25 ml min(-1)) and (23 ± 3 versus 17 ± 2 ml min(-1); both P flow. Our collective data indicate that, among matched workloads, shorter contraction duration and greater muscle fibre recruitment augment FBF and during mild-intensity forearm exercise, and that muscle blood flow is more closely related to metabolic cost ( ) rather than contractile work per se during steady-state exercise in humans.

  7. Effect of thyroxine on cellular oxygen-consumption and glucose uptake: evidence of an effect of total T4 and not "free T4"

    DEFF Research Database (Denmark)

    Kvetny, J; Matzen, L E

    1990-01-01

    Recent studies of cellular T4 and T3 uptake have indicated active transport of the hormones into the cell rather than passive diffusion of the non-protein bound fraction. In order to study the significance of the extracellular environment, oxygen consumption and glucose uptake were examined...... in human mononuclear blood cells. Cells were incubated in protein free medium and in human serum totally depleted of thyroid hormones by resin treatment and fixed amounts of T4 (total T4 = 0-50-100-5000 nmol/l; free T4 = 0-5-11-5600 pmol/l) were added. Thyroxine stimulated glucose uptake and oxygen......-consumption in a dose dependent manner but the T4 stimulation was dependent on the total concentration of T4 and did not differ between serum incubation or non-protein containing medium. Addition of ANS (100 mg/l) which inhibits binding of T4 to TBG, did not increase T4 effect in serum. Inhibition of the Na...

  8. Consumo de oxigênio pós-prandial de juvenis do pampo Trachinotus marginatus Postprandial oxygen consumption of juvenile pompano Trachinotus marginatus

    Directory of Open Access Journals (Sweden)

    Viviana Lisboa Cunha

    2009-07-01

    Full Text Available Para determinar a viabilidade do cultivo de uma espécie, é importante o conhecimento dos fatores limitantes para sua produção. Conhecer a taxa de consumo de oxigênio pós-prandial pode auxiliar na determinação da freqüência alimentar ideal para as espécies cultivadas. O objetivo deste trabalho foi estudar a taxa de consumo de oxigênio pós-prandial para juvenis do pampo Trachinotus marginatus. A avaliação do consumo de oxigênio foi feita a 24°C e 33‰, com pampos (9,64±0,2g alimentados com 12% da biomassa por dia com dieta NRD INVE (59% proteína. Foi observado um pico de consumo de oxigênio 30min após a alimentação (1,06mgO2 g-1 h-1 e seu retorno ao nível de jejum (0,79mgO2 g-1 h-1 depois de decorridos mais 120min. A alimentação de juvenis de pampo pode ser realizada com uma freqüência de aproximadamente oito vezes por dia, pois a cada 2,5h a taxa de consumo de oxigênio já não mostra a elevação característica da fase pós-prandial, sugerindo que os processos de digestão e assimilação dos nutrientes estejam finalizados.In order to determine the viability of new species for aquaculture, it is important to know the limiting factors for its production. The knowledge about postprandial oxygen consumption of fish is useful to estimate the time for returning to appetite and allows to estimate the proper feeding frequency. The objective of this research was to study the postprandial oxygen consumption of juvenile pompano Trachinotus marginatus. Oxygen consumption rate was determined at 24°C and 33‰ and fish (9.64±0.2g were fed daily with 12% total of biomass NRD INVE diet (59% protein. Postprandial increase in oxygen consumption was observed 30min after feeding (1.06mgO2 g-1 h-1, and it returned to the routine metabolic rate (0.79mgO2 g-1 h-1 within the next 120min. According to these results, it seems appropriated to feed juvenile pompano 8 times per day, because every 2.5h the oxygen consumption rate declines to

  9. Automatic labeling method for injectable 15O-oxygen using hemoglobin-containing liposome vesicles and its application for measurement of brain oxygen consumption by PET

    International Nuclear Information System (INIS)

    Tiwari, Vijay Narayan; Kiyono, Yasushi; Kobayashi, Masato; Mori, Tetsuya; Kudo, Takashi; Okazawa, Hidehiko; Fujibayashi, Yasuhisa

    2010-01-01

    Introduction: The aim of this study was to develop an injectable 15 O-O 2 system using hemoglobin-containing vesicles (HbV), a type of artificial red blood cell, and to investigate the feasibility of 15 O 2 -labeled HbV ( 15 O 2 -HbV) to measure cerebral metabolic rate of oxygen (CMRO 2 ) in rats. Methods: The direct bubbling method was combined with vortexing to enhance labeling efficiency of HbV with 15 O-O 2 gas. L-Cysteine was added as a reductant to protect hemoglobin molecules in HbV from oxidation at different concentrations, and labeling efficiencies were also compared. Measurement of cerebral blood flow (CBF) and CMRO 2 in five normal rats was performed using a small animal PET scanner after the injection of H 2 15 O and 15 O 2 -HbV to evaluate the precision of hemodynamic parameters quantitatively. Results: The labeling efficiency of HbV was significantly increased when vortexing and bubbling were combined compared with the simple bubbling method (P 15 O-O 2 combined with vortexing and the addition of 2.8 mM L-cysteine in HbV solution. The mean radioactivity of 214.4±7.8 MBq/mL HbV was obtained using this method. PET scans using 15 O 2 -HbV and H 2 15 O yielded a mean CMRO 2 value of 6.8±1.4 (mL/min per 100 g) in rats with normal CBF of 51.4±7.9 (mL/min per 100 g). Conclusion: Addition of L-cysteine to HbV and simple direct bubbling of 15 O-O 2 gas combined with vortexing was the most efficient method for preparation of 15 O 2 -HbV. The present injectable system using 15 O 2 -HbV was successfully utilized to measure CMRO 2 in rats, indicating that this new method could be useful for animal models to measure oxygen metabolism in the brain.

  10. Automatic labeling method for injectable {sup 15}O-oxygen using hemoglobin-containing liposome vesicles and its application for measurement of brain oxygen consumption by PET

    Energy Technology Data Exchange (ETDEWEB)

    Tiwari, Vijay Narayan [Biomedical Imaging Research Center, University of Fukui, Fukui (Japan)], E-mail: tiwaridr@u-fukui.ac.jp; Kiyono, Yasushi; Kobayashi, Masato; Mori, Tetsuya; Kudo, Takashi [Biomedical Imaging Research Center, University of Fukui, Fukui (Japan); Okazawa, Hidehiko [Biomedical Imaging Research Center, University of Fukui, Fukui (Japan); Research and Education Program for Life Science, University of Fukui, Fukui (Japan); Fujibayashi, Yasuhisa [Biomedical Imaging Research Center, University of Fukui, Fukui (Japan); Research and Education Program for Life Science, University of Fukui, Fukui (Japan)], E-mail: yfuji@u-fukui.ac.jp

    2010-01-15

    Introduction: The aim of this study was to develop an injectable {sup 15}O-O{sub 2} system using hemoglobin-containing vesicles (HbV), a type of artificial red blood cell, and to investigate the feasibility of {sup 15}O{sub 2}-labeled HbV ({sup 15}O{sub 2}-HbV) to measure cerebral metabolic rate of oxygen (CMRO{sub 2}) in rats. Methods: The direct bubbling method was combined with vortexing to enhance labeling efficiency of HbV with {sup 15}O-O{sub 2} gas. L-Cysteine was added as a reductant to protect hemoglobin molecules in HbV from oxidation at different concentrations, and labeling efficiencies were also compared. Measurement of cerebral blood flow (CBF) and CMRO{sub 2} in five normal rats was performed using a small animal PET scanner after the injection of H{sub 2}{sup 15}O and {sup 15}O{sub 2}-HbV to evaluate the precision of hemodynamic parameters quantitatively. Results: The labeling efficiency of HbV was significantly increased when vortexing and bubbling were combined compared with the simple bubbling method (P<.05). The most efficient method for labeling was bubbling of {sup 15}O-O{sub 2} combined with vortexing and the addition of 2.8 mM L-cysteine in HbV solution. The mean radioactivity of 214.4{+-}7.8 MBq/mL HbV was obtained using this method. PET scans using {sup 15}O{sub 2}-HbV and H{sub 2}{sup 15}O yielded a mean CMRO{sub 2} value of 6.8{+-}1.4 (mL/min per 100 g) in rats with normal CBF of 51.4{+-}7.9 (mL/min per 100 g). Conclusion: Addition of L-cysteine to HbV and simple direct bubbling of {sup 15}O-O{sub 2} gas combined with vortexing was the most efficient method for preparation of {sup 15}O{sub 2}-HbV. The present injectable system using {sup 15}O{sub 2}-HbV was successfully utilized to measure CMRO{sub 2} in rats, indicating that this new method could be useful for animal models to measure oxygen metabolism in the brain.

  11. Oxygen consumption rates in hovering hummingbirds reflect substrate-dependent differences in P/O ratios: carbohydrate as a 'premium fuel'.

    Science.gov (United States)

    Welch, Kenneth C; Altshuler, Douglas L; Suarez, Raul K

    2007-06-01

    The stoichiometric relationship of ATP production to oxygen consumption, i.e. the P/O ratio, varies depending on the nature of the metabolic substrate used. The latest estimates reveal a P/O ratio approximately 15% higher when glucose is oxidized compared with fatty acid oxidation. Because the energy required to produce aerodynamic lift for hovering is independent of the metabolic fuel oxidized, we hypothesized that the rate of oxygen consumption, VO2, should decline as the respiratory quotient, RQ (VCO2/VO2), increases from 0.71 to 1.0 as hummingbirds transition from a fasted to a fed state. Here, we show that hovering VO2 values in rufous (Selasphorus rufus) and Anna's hummingbirds (Calypte anna) are significantly greater when fats are metabolized (RQ=0.71) than when carbohydrates are used (RQ=1.0). Because hummingbirds gained mass during our experiments, making mass a confounding variable, we estimated VO2 per unit mechanical power output. Expressed in this way, the difference in VO2 when hummingbirds display an RQ=0.71 (fasted) and an RQ=1.0 (fed) is between 16 and 18%, depending on whether zero or perfect elastic energy storage is assumed. These values closely match theoretical expectations, indicating that a combination of mechanical power estimates and ;indirect calorimetry', i.e. the measurement of rates of gas exchange, enables precise estimates of ATP turnover and metabolic flux rates in vivo. The requirement for less oxygen when oxidizing carbohydrate suggests that carbohydrate oxidation may facilitate hovering flight in hummingbirds at high altitude.

  12. Effect of oxygenate additive on diesel engine fuel consumption and emissions operating with biodiesel-diesel blend at idling conditions

    Science.gov (United States)

    Mahmudul, H. M.; Hagos, F. Y.; Mamat, R.; Noor, M. M.; Yusri, I. M.

    2017-10-01

    Biodiesel is promising alternative fuel to run the automotive engine but idling is the main problem to run the vehicles in a big city. Vehicles running with idling condition cause higher fuel supply and higher emission level due to being having fuel residues in the exhaust. The purpose of this study is to evaluate the impact of alcohol additive on fuel consumption and emissions parameters under idling conditions when a multicylinder diesel engine operates with the diesel-biodiesel blend. The study found that using 5% butanol as an additive with B5 (5% Palm biodiesel + 95% diesel) blends fuel lowers brake specific fuel consumption and CO emissions by 38% and 20% respectively. But the addition of butanol increases NOx and CO2 emissions. Based on the result it can be said that 5% butanol can be used in a diesel engine with B5 without any engine modifications to tackle the idling problem.

  13. Accelerated oxygen consumption by catecholamines in the presence of aromatic nitro and nitroso compounds. Implications and neurotoxicity of nitro compounds

    International Nuclear Information System (INIS)

    Sridhar, K.

    1981-01-01

    The interactions of catecholamines with nitro and nitroso compounds are studied in view of the possible involvement of catecholamine type neurotransmitters in neurotoxicity caused by hypoxic cell sensitizers. The data reported suggest that neurotoxicity of nitro compounds may be due to depletion of oxygen, catecholamines and ascorbate in nerve tissue with concomitant generation of toxic species such as hydroxyl, hydronitroxyl and superoxide free radicals as well as nitroso and quinonoid derivatives. 5 references, 1 figure

  14. The kinetics of oxygen and SO2 consumption by red wines. What do they tell about oxidation mechanisms and about changes in wine composition?

    Science.gov (United States)

    Carrascón, Vanesa; Vallverdú-Queralt, Anna; Meudec, Emmanuelle; Sommerer, Nicolas; Fernandez-Zurbano, Purificación; Ferreira, Vicente

    2018-02-15

    This work seeks to understand the kinetics of O 2 and SO 2 consumption of air-saturated red wine as a function of its chemical composition, and to describe the chemical changes suffered during the process in relation to the kinetics. Oxygen Consumption Rates (OCRs) are faster with higher copper and epigallocatechin contents and with higher absorbance at 620nm and slower with higher levels of gallic acid and catechin terminal units in tannins. Acetaldehyde Reactive Polyphenols (ARPs) may be key elements determining OCRs. It is confirmed that SO 2 is poorly consumed in the first saturation. Phenylalanine, methionine and maybe, cysteine, seem to be consumed instead. A low SO 2 consumption is favoured by low levels of SO 2 , by a low availability of free SO 2 caused by a high anthocyanin/tannin ratio, and by a polyphenolic profile poor in epigallocatechin and rich in catechin-rich tannins. Wines consuming SO 2 efficiently consume more epigallocatechin, prodelphinidins and procyanidins. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2015-12-01

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

  16. Spatiotemporal dynamics of phosphorus release, oxygen consumption and greenhouse gas emissions after localised soil amendment with organic fertilisers

    DEFF Research Database (Denmark)

    Christel, Wibke; Zhu, Kun; Hoefer, Christoph

    2016-01-01

    processes and fixation in the residue sphere, giving rise to distinct differences in nutrient availability, soil oxygen content and greenhouse gas (GHG) production. In this study we investigated the spatiotemporal dynamics of the reaction of manure solids and manure solids char with soil, focusing...... on their phosphorus (P) availability, as current emphasis on improving societal P efficiency through recycling waste or bio-based fertilisers necessitates a sound understanding of their behaviour. Soil layers amended at a constant P application rate with either pig manure solids or char made from pig manure solids...

  17. Feasibility of a 12-month-exercise intervention during and after radiation and chemotherapy in cancer patients: impact on quality of life, peak oxygen consumption, and body composition.

    Science.gov (United States)

    Grabenbauer, Alexander; Grabenbauer, Andrea J; Lengenfelder, Rosa; Grabenbauer, Gerhard G; Distel, Luitpold V

    2016-03-16

    Accumulating evidence suggests that exercise is effective in treating many of the acute and chronic side effects of anti-cancer therapy. A recent meta-analysis supported the use of exercise to prevent or treat fatigue and lymphoedema and to improve functional status in breast cancer patients. This trial was intended as a controlled, prospective feasibility study evaluating the impact of physical exercise (PE) in cancer patients during and after treatment with radio- and chemotherapy. Inclusion criteria were previous or ongoing treatment for cancer, motivation for PE of 0.5-1hour duration at least twice weekly for at least 3 months. Continuation of PE was encouraged thereafter. Every three months the following endpoints were assessed: Peak oxygen consumption as measured by supervised cardiopulmonary exercise test, body composition and quality of life. A total of 45 patients were included with a median age of 49 years. Forty were female and five male. Cancer types were: Breast cancer (n = 30/67 %), gastrointestinal cancer (n = 5/12 %), other types (n = 10/22 %). Thirty-eight (84 %) of the patients were included during curative treatment of their disease. Seven (16 %) were considered palliative. Adherence to the PE-programme longer than 6 months was noted for 41/45 (91 %) of the patients. Intensity of PE was thrice weekly in 32/45 (71 %), twice weekly in 11/45 (24 %). Two of 45 patients (5 %) had no PE. Mean peak oxygen consumption increased from 18.8 ± 5.6 ml/min/kg to 20.5 ± 3 ml/min/kg and 19.9 ± 4.7 ml/min/kg at 3 months (p = 0.005) and 12 months (p = 0.003), respectively. Median fat mass decreased from 30.7 ± 15 kg to 28.9 ± 15 kg and 29.5 ± 13 kg at 3 months (p = 0.001) and 12 months (p = 0.017), respectively. Global health status scores increased from a median baseline value of 54.9 ± 16.3 to 66.4 ± 14 % and 68.0 ± 20.3 % at 3 months (p = 0.001) and 12 months (p = 0.002), respectively. This exercise programme in cancer patients with 2-3 weekly

  18. Relationship between iodine-123-beta-methyl-p-iodophenyl-pentadecanoic acid washout ratio and oxygen consumption in normal and ischemic myocardium

    International Nuclear Information System (INIS)

    Saito, Kimimasa; Okamoto, Ryuji; Saito, Yasuhiro

    1997-01-01

    The relationship between oxygen consumption and iodine-123-beta-methyl-p-iodophenyl-pentadecanoic acid ( 123 I-BMIPP) washout at rest and after exercise was investigated in normal and ischemic myocardium. Sixteen healthy volunteers and 14 patients with ischemic heart disease were examined. After injection of 111 MBq of 123 I-BMIPP, serial single photon emission computed tomography imaging was performed to evaluate washout ratio after 30 min and 1 hour of rest and after exercise. In the volunteers, the mean washout ratio was 3.3±3.5% after 1 hour of rest and increased during exercise. The exercise washout ratio showed a better correlation with net pressure rate product (net PRP: cumulative values of PRP during exercise) than with the peak PRP. The exercise washout ratio showed a strong correlation with the net PRP in the range from 180 to 300x10 3 mmHg·beat/min and a plateau of 10-15%. In the nine ischemic patients with net PRP≥300x10 3 mmHg·beat/min, the exercise washout ratio values were significantly elevated in normal segments relative to ischemic segments (10.1±1.9% vs 4.7±2.9%, p 3 mmHg·beat/min, washout ratio at rest and after exercise did not differ significantly between normal and ischemic segments. 123 I-BMIPP washout ratio increased with increased oxygen consumption during exercise in normal myocardium but not in ischemic myocardium. The patient must exercise before fatty acid metabolism can be compared between normal and ischemic myocardium. (author)

  19. HIGD1A Regulates Oxygen Consumption, ROS Production, and AMPK Activity during Glucose Deprivation to Modulate Cell Survival and Tumor Growth

    Directory of Open Access Journals (Sweden)

    Kurosh Ameri

    2015-02-01

    Full Text Available Hypoxia-inducible gene domain family member 1A (HIGD1A is a survival factor induced by hypoxia-inducible factor 1 (HIF-1. HIF-1 regulates many responses to oxygen deprivation, but viable cells within hypoxic perinecrotic solid tumor regions frequently lack HIF-1α. HIGD1A is induced in these HIF-deficient extreme environments and interacts with the mitochondrial electron transport chain to repress oxygen consumption, enhance AMPK activity, and lower cellular ROS levels. Importantly, HIGD1A decreases tumor growth but promotes tumor cell survival in vivo. The human Higd1a gene is located on chromosome 3p22.1, where many tumor suppressor genes reside. Consistent with this, the Higd1a gene promoter is differentially methylated in human cancers, preventing its hypoxic induction. However, when hypoxic tumor cells are confronted with glucose deprivation, DNA methyltransferase activity is inhibited, enabling HIGD1A expression, metabolic adaptation, and possible dormancy induction. Our findings therefore reveal important new roles for this family of mitochondrial proteins in cancer biology.

  20. Spatiotemporal dynamics of phosphorus release, oxygen consumption and greenhouse gas emissions after localised soil amendment with organic fertilisers

    Energy Technology Data Exchange (ETDEWEB)

    Christel, Wibke [Department for Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C (Denmark); Department of Commerce, Industry and Agriculture, Danish Environmental Protection Agency, 1401 Copenhagen C (Denmark); Zhu, Kun [Department for Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C (Denmark); College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193 (China); Hoefer, Christoph [Rhizosphere Ecology and Biogeochemistry Group, Department of Forest and Soil Sciences, University of Natural Resources and Life Sciences, Vienna, Konrad-Lorenz-Strasse 24, 3430 Tulln (Austria); Kreuzeder, Andreas [Rhizosphere Ecology and Biogeochemistry Group, Department of Forest and Soil Sciences, University of Natural Resources and Life Sciences, Vienna, Konrad-Lorenz-Strasse 24, 3430 Tulln (Austria); Land Salzburg, Natur- und Umweltschutz, Gewerbe (Abteilung 5), Michael-Pacher-Straße 36, 5020 Salzburg (Austria); Santner, Jakob [Rhizosphere Ecology and Biogeochemistry Group, Department of Forest and Soil Sciences, University of Natural Resources and Life Sciences, Vienna, Konrad-Lorenz-Strasse 24, 3430 Tulln (Austria); Division of Agronomy, Department of Crop Sciences, University of Natural Resources and Life Sciences, Vienna, Konrad-Lorenz-Strasse 24, 3430 Tulln (Austria); Bruun, Sander; Magid, Jakob [Department for Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C (Denmark); Jensen, Lars Stoumann, E-mail: lsj@plen.ku.dk [Department for Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C (Denmark)

    2016-06-01

    Organic fertilisation inevitably leads to heterogeneous distribution of organic matter and nutrients in soil, i.e. due to uneven surface spreading or inhomogeneous incorporation. The resulting localised hotspots of nutrient application will induce various biotic and abiotic nutrient turnover processes and fixation in the residuesphere, giving rise to distinct differences in nutrient availability, soil oxygen content and greenhouse gas (GHG) production. In this study we investigated the spatiotemporal dynamics of the reaction of manure solids and manure solids char with soil, focusing on their phosphorus (P) availability, as current emphasis on improving societal P efficiency through recycling waste or bio-based fertilisers necessitates a sound understanding of their behaviour. Soil layers amended at a constant P application rate with either pig manure solids or char made from pig manure solids were incubated for three weeks between layers of non-amended, P-depleted soil. Spatial and temporal changes in and around the amendment layers were simultaneously investigated in this study using a sandwich sensor consisting of a planar oxygen optode and multi-element diffusive gradients in thin films (DGT) gels, combined with GHG emission measurements. After three weeks of incubation, the soil containing a layer amended with manure solids had a lower overall O{sub 2} content and had emitted significantly more CO{sub 2} than the non-amended control or the char-amended soil. The P availability from manure solids was initially higher than that from the char, but decreased over time, whereas from the char-amended layer P availability increased in the same period. In both treatments, increases in P availability were confined to the amended soil layer and did not greatly affect P availability in the directly adjacent soil layers during the three-week incubation. These results highlight the importance of placing organic P fertilisers close to where the plant roots will grow in

  1. Spatiotemporal dynamics of phosphorus release, oxygen consumption and greenhouse gas emissions after localised soil amendment with organic fertilisers

    International Nuclear Information System (INIS)

    Christel, Wibke; Zhu, Kun; Hoefer, Christoph; Kreuzeder, Andreas; Santner, Jakob; Bruun, Sander; Magid, Jakob; Jensen, Lars Stoumann

    2016-01-01

    Organic fertilisation inevitably leads to heterogeneous distribution of organic matter and nutrients in soil, i.e. due to uneven surface spreading or inhomogeneous incorporation. The resulting localised hotspots of nutrient application will induce various biotic and abiotic nutrient turnover processes and fixation in the residuesphere, giving rise to distinct differences in nutrient availability, soil oxygen content and greenhouse gas (GHG) production. In this study we investigated the spatiotemporal dynamics of the reaction of manure solids and manure solids char with soil, focusing on their phosphorus (P) availability, as current emphasis on improving societal P efficiency through recycling waste or bio-based fertilisers necessitates a sound understanding of their behaviour. Soil layers amended at a constant P application rate with either pig manure solids or char made from pig manure solids were incubated for three weeks between layers of non-amended, P-depleted soil. Spatial and temporal changes in and around the amendment layers were simultaneously investigated in this study using a sandwich sensor consisting of a planar oxygen optode and multi-element diffusive gradients in thin films (DGT) gels, combined with GHG emission measurements. After three weeks of incubation, the soil containing a layer amended with manure solids had a lower overall O_2 content and had emitted significantly more CO_2 than the non-amended control or the char-amended soil. The P availability from manure solids was initially higher than that from the char, but decreased over time, whereas from the char-amended layer P availability increased in the same period. In both treatments, increases in P availability were confined to the amended soil layer and did not greatly affect P availability in the directly adjacent soil layers during the three-week incubation. These results highlight the importance of placing organic P fertilisers close to where the plant roots will grow in order to

  2. Effect of the dimetilsulfoxido in the response chemiluminescent and the consumption of oxygen of neutrophils activated human

    International Nuclear Information System (INIS)

    Garcia, J.

    2001-01-01

    Dimethylsulfoxide (DMSO), a hydroxyl radical scavenger, exerted a dose dependent inhibition on the luminol and lucigenin-enhanced chemiluminescent responses of human neutrophils activated with soluble and particulate stimulants. DMSO inhibition of the luminol chemiluminescense induced by calcium ionophore A23187 was probably due to OH scavenging, whereas inhibition of the lucigenin chemiluminescence suggested DMSO negatively affects the NADPH-dependent membrane oxidase of neutrophils. In agreement with this, DMSO moderately inhibited O2 consumption in PMN suspensions stimulated with chemotactic peptide and opsonized zymosan-induced luminol chemiluminescense was observed only when added before or in conjunction with stimulants, whereas A23187-induced chemiluminescense was inhibited by DMSO regardless of time of addition. Washing of DMSO-treated PMN resulted in increased luminol enhanced chemiluminescense in response to chemotactic peptide and opsonized zymosan. This is consistent with the idea that DMSO may be interfering with activation of the membrane subunits of the oxidase by translocation and docking of the cytoplasmic, regulatory subunits. These data imply that DMSO inhibits neutrophil chemiluminescense both by OH scavenging and interfering with oxidase activation. Key words:Dimethylsulfoxide, chemiluminescent, luminol, lucigenin,neutrophils [es

  3. Impaired Economy of Gait and Decreased Six-Minute Walk Distance in Parkinson's Disease

    Directory of Open Access Journals (Sweden)

    Leslie I. Katzel

    2012-01-01

    Full Text Available Changes in the biomechanics of gait may alter the energy requirements of walking in Parkinson's Disease (PD. This study investigated economy of gait during submaximal treadmill walking in 79 subjects with mild to moderate PD and the relationship between gait economy and 6-minute walk distance (6 MW. Oxygen consumption (VO2 at the self-selected treadmill walking speed averaged 64% of peak oxygen consumption (VO2 peak. Submaximal VO2 levels exceeded 70% of VO2 peak in 30% of the subjects. Overall the mean submaximal VO2 was 51% higher than VO2 levels expected for the speed and grade consistent with severe impairment in economy of gait. There was an inverse relationship between economy of gait and 6MW (r=−0.31, P<0.01 and with the self-selected walking speed (r=−0.35, P<0.01. Thus, the impairment in economy of gait and decreased physiologic reserve result in routine walking being performed at a high percentage of VO2 peak.

  4. Characterization of Activity and Cardiovascular Responses During Surfing in Recreational Male Surfers Between the Ages of 18 and 75 Years Old.

    Science.gov (United States)

    LaLanne, Christine L; Cannady, Michael S; Moon, Joseph F; Taylor, Danica L; Nessler, Jeff A; Crocker, George H; Newcomer, Sean C

    2017-04-01

    Participation in surfing has evolved to include all age groups. Therefore, the purpose of this study was to determine whether activity levels and cardiovascular responses to surfing change with age. Surfing time and heart rate (HR) were measured for the total surfing session and within each activity of surfing (paddling, sitting, wave riding, and miscellaneous). Peak oxygen consumption (VO 2peak ) was also measured during laboratory-based simulated surfboard paddling on a modified swim bench ergometer. VO 2peak decreased with age during simulated paddling (r = -.455, p surfing (p = .837) and time spent within each activity of surfing did not differ with age (n = 160). Mean HR during surfing significantly decreased with age (r = -.231, p = .004). However, surfing HR expressed as a percent of age-predicted maximum increased significantly with age. Therefore, recreational surfers across the age spectrum are achieving intensities and durations that are consistent with guidelines for cardiovascular health.

  5. Pediatric exercise testing. In health and disease

    NARCIS (Netherlands)

    Bongers, B.C.

    2013-01-01

    Measuring peak oxygen uptake (VO2peak) during progressive cardiopulmonary exercise testing (CPET) up to maximal exertion is widely recognized as the best single measure of aerobic exercise capacity. It is an important determinant of health, even in childhood and adolescence. Measuring VO2peak

  6. Recombinant human interleukin-6 infusion during low-intensity exercise does not enhance whole body lipolysis or fat oxidation in humans

    DEFF Research Database (Denmark)

    Hiscock, N; Fischer, C P; Sacchetti, M

    2005-01-01

    The present study examined the role of the cytokine IL-6 in the regulation of fatty acid metabolism during exercise in humans. Six well-trained males completed three trials of 120 min of cycle ergometry at 70% peak O(2) consumption (Vo(2 peak); MOD) and 40% Vo(2 peak) with (LOW + IL-6) and withou...

  7. Feasibility of a 12-month-exercise intervention during and after radiation and chemotherapy in cancer patients: impact on quality of life, peak oxygen consumption, and body composition

    International Nuclear Information System (INIS)

    Grabenbauer, Alexander; Grabenbauer, Andrea J.; Lengenfelder, Rosa; Grabenbauer, Gerhard G.; Distel, Luitpold V.

    2016-01-01

    Accumulating evidence suggests that exercise is effective in treating many of the acute and chronic side effects of anti-cancer therapy. A recent meta-analysis supported the use of exercise to prevent or treat fatigue and lymphoedema and to improve functional status in breast cancer patients. This trial was intended as a controlled, prospective feasibility study evaluating the impact of physical exercise (PE) in cancer patients during and after treatment with radio- and chemotherapy. Inclusion criteria were previous or ongoing treatment for cancer, motivation for PE of 0.5-1hour duration at least twice weekly for at least 3 months. Continuation of PE was encouraged thereafter. Every three months the following endpoints were assessed: Peak oxygen consumption as measured by supervised cardiopulmonary exercise test, body composition and quality of life. A total of 45 patients were included with a median age of 49 years. Forty were female and five male. Cancer types were: Breast cancer (n = 30/67 %), gastrointestinal cancer (n = 5/12 %), other types (n = 10/22 %). Thirty-eight (84 %) of the patients were included during curative treatment of their disease. Seven (16 %) were considered palliative. Adherence to the PE-programme longer than 6 months was noted for 41/45 (91 %) of the patients. Intensity of PE was thrice weekly in 32/45 (71 %), twice weekly in 11/45 (24 %). Two of 45 patients (5 %) had no PE. Mean peak oxygen consumption increased from 18.8 ± 5.6 ml/min/kg to 20.5 ± 3 ml/min/kg and 19.9 ± 4.7 ml/min/kg at 3 months (p = 0.005) and 12 months (p = 0.003), respectively. Median fat mass decreased from 30.7 ± 15 kg to 28.9 ± 15 kg and 29.5 ± 13 kg at 3 months (p = 0.001) and 12 months (p = 0.017), respectively. Global health status scores increased from a median baseline value of 54.9 ± 16.3 to 66.4 ± 14 % and 68.0 ± 20.3 % at 3 months (p = 0.001) and 12 months (p = 0.002), respectively. This exercise programme in cancer patients with 2–3 weekly

  8. Electrostimulation improves muscle perfusion but does not affect either muscle deoxygenation or pulmonary oxygen consumption kinetics during a heavy constant-load exercise.

    Science.gov (United States)

    Layec, Gwenael; Millet, Grégoire P; Jougla, Aurélie; Micallef, Jean-Paul; Bendahan, David

    2008-02-01

    Electromyostimulation (EMS) is commonly used as part of training programs. However, the exact effects at the muscle level are largely unknown and it has been recently hypothesized that the beneficial effect of EMS could be mediated by an improved muscle perfusion. In the present study, we investigated rates of changes in pulmonary oxygen consumption (VO(2p)) and muscle deoxygenation during a standardized exercise performed after an EMS warm-up session. We aimed at determining whether EMS could modify pulmonary O(2) uptake and muscle deoxygenation as a result of improved oxygen delivery. Nine subjects performed a 6-min heavy constant load cycling exercise bout preceded either by an EMS session (EMS) or under control conditions (CONT). VO(2p) and heart rate (HR) were measured while deoxy-(HHb), oxy-(HbO(2)) and total haemoglobin/myoglobin (Hb(tot)) relative contents were measured using near infrared spectroscopy. EMS significantly increased (P < 0.05) the Hb(tot) resting level illustrating a residual hyperaemia. The EMS priming exercise did not affect either the HHb time constant (17.7 +/- 14.2 s vs. 13.1 +/- 2.3 s under control conditions) or the VO(2p) kinetics (time-constant = 18.2 +/- 5.2 s vs. 15.4 +/- 4.6 s under control conditions). Likewise, the other VO(2p) parameters were unchanged. Our results further indicated that EMS warm-up improved muscle perfusion through a residual hyperaemia. However, neither VO(2p) nor [HHb] kinetics were modified accordingly. These results suggest that improved O(2) delivery by residual hyperaemia induced by EMS does not accelerate the rate of aerobic metabolism during heavy exercise at least in trained subjects.

  9. Delayed Effects of Remote Limb Ischemic Preconditioning on Maximum Oxygen Consumption, Lactate Release and Pulmonary Function Tests in Athletes and non-Athletes

    Directory of Open Access Journals (Sweden)

    Mahnaz Momeni

    2016-11-01

    Full Text Available Background: Remote Ischemic Preconditioning (RIPC improves exercise performance, and since this phenomenon has two phases, the aim of the current study was to investigate the delayed effects of remote ischemic preconditioning on cardiopulmonary function in athletes and non-athletes. Materials and Methods: 25 male and female students were studied in two main athletes and non-athletes groups. RIPC was induced by using 3 cycles of alternative 5 minutes ischemia and 5 minutes reperfusion at arms of participants. Cardiopulmonary tests were measured before, after and 24 hours after inducing remote ischemic preconditioning. Maximum oxygen consumption (VO2max estimated by using queen steps test. Results: Analysis of data demonstrated that delayed RIPC in non-athletes group caused significant improvement in Forced Expiratory Volume in one second (FEV1 and Maximum Voluntary Ventilation (MVV and noticeable improvement in some other parameters of pulmonary function tests. Moreover, it decreased systolic blood pressure and heart rate and decreased lactate release in both groups especially athletes group but it had no significant effect on VO2max of both groups. Conclusion: Delayed RIPC improves cardiovascular function of athletes and pulmonary function of non-athletes subjects. Thus, it can be considered as a good replacement for doping to improve sports performance of subjects in sports tournaments.

  10. Study of the influence of fuel load and slope on a fire spreading across a bed of pine needles by using oxygen consumption calorimetry

    Science.gov (United States)

    Tihay, V.; Morandini, F.; Santoni, P. A.; Perez-Ramirez, Y.; Barboni, T.

    2012-11-01

    A set of experiments using a Large Scale Heat Release Rate Calorimeter was conducted to test the effects of slope and fuel load on the fire dynamics. Different parameters such as the geometry of the flame front, the rate of spread, the mass loss rate and the heat release rate were investigated. Increasing the fuel load or the slope modifies the fire behaviour. As expected, the flame length and the rate of spread increase when fuel load or slope increases. The heat release rate does not reach a quasi-steady state when the propagation takes place with a slope of 20° and a high fuel load. This is due to an increase of the length of the fire front leading to an increase of fuel consumed. These considerations have shown that the heat release can be estimated with the mass loss rate by considering the effective heat of combustion. This approach can be a good alternative to estimate accurately the fireline intensity when the measure of oxygen consumption is not possible.

  11. Study of the influence of fuel load and slope on a fire spreading across a bed of pine needles by using oxygen consumption calorimetry

    International Nuclear Information System (INIS)

    Tihay, V; Morandini, F; Santoni, P A; Perez-Ramirez, Y; Barboni, T

    2012-01-01

    A set of experiments using a Large Scale Heat Release Rate Calorimeter was conducted to test the effects of slope and fuel load on the fire dynamics. Different parameters such as the geometry of the flame front, the rate of spread, the mass loss rate and the heat release rate were investigated. Increasing the fuel load or the slope modifies the fire behaviour. As expected, the flame length and the rate of spread increase when fuel load or slope increases. The heat release rate does not reach a quasi-steady state when the propagation takes place with a slope of 20° and a high fuel load. This is due to an increase of the length of the fire front leading to an increase of fuel consumed. These considerations have shown that the heat release can be estimated with the mass loss rate by considering the effective heat of combustion. This approach can be a good alternative to estimate accurately the fireline intensity when the measure of oxygen consumption is not possible.

  12. Contribution of proton leak to oxygen consumption in skeletal muscle during intense exercise is very low despite large contribution at rest.

    Directory of Open Access Journals (Sweden)

    Bernard Korzeniewski

    Full Text Available A computer model was used to simulate the dependence of protonmotive force (Δp, proton leak and phenomenological (involving proton leak ATP/O2 ratio on work intensity in skeletal muscle. Δp, NADH and proton leak decreased with work intensity. The contribution of proton leak to oxygen consumption ([Formula: see text] decreased from about 60% at rest to about 3 and 1% at moderate and heavy/severe exercise, respectively, while the ATP/O2 ratio increased from 2.1 to 5.5 and 5.7. A two-fold increase in proton leak activity or its decrease to zero decreased/increased the ATP/O2 ratio by only about 3 and 1% during moderate and heavy/severe exercise, respectively. The low contribution of proton leak to [Formula: see text] in intensively working skeletal muscle was mostly caused by a huge increase in ATP usage intensity during rest-to-work transition, while OXPHOS, and thus oxidative ATP supply and [Formula: see text] related to it, was mostly stimulated by high each-step activation (ESA of OXPHOS complexes. The contribution of proton leak to [Formula: see text] and ATP/O2 ratio in isolated mitochondria should not be directly extrapolated to working muscle, as mitochondria lack ESA, at least in the absence of Ca2+, and therefore [Formula: see text] cannot be elevated as much as in intact muscle.

  13. Effects of x-irradiation on cell division, oxygen consumption, and growth medium pH of an insect cell line cultured in vitro

    International Nuclear Information System (INIS)

    Koval, T.M.; Myser, W.C.; Hink, W.F.

    1975-01-01

    Cultured Trichoplusia ni cells in exponential growth were administered x-ray doses of 10,000 R and then subcultured. The untreated cell population began exponential growth within a few hours after subculture, eventually reaching stationary growth phase 96 hr later at a cell density of 2.08 x 10 6 cells/ml, whereas the irradiated cell population did not change for 24 hr after irradiation and then began exponential growth at a rate similar to that of control cells, also reaching stationary phase at 96 hr, but at a cell density of 0.93 x 10 6 cells/ml, which is less than half the maximum density of controls. From 24 to 96 hr after treatment, the x-irradiated cells were characterized by an increased consumption of oxygen that was nearly twice the amount utilized by control cells. The pH of the cell growth medium increases over 96 hr from 6.3 to 6.6 for irradiated as well as for untreated cultures, but since the number of x-rayed cells is less than half the number of untreated cells, the pH increase, per cell, of medium from irradiated cultures is about twice that of medium from control cultures

  14. The contribution of gastric digestion and ingestion of amino acids on the postprandial rise in oxygen consumption, heart rate and growth of visceral organs in pythons.

    Science.gov (United States)

    Enok, Sanne; Simonsen, Lasse Stærdal; Wang, Tobias

    2013-05-01

    To investigate the contribution of gastric and intestinal processes to the postprandial rise in metabolism in pythons (Python regius), we measured oxygen consumption after ligation of the pyloric sphincter to prevent the chyme from entering the intestine. Pyloric blockade reduced the postprandial rise in metabolism during the first 18h after ingestion of mice amounting to 18% of the snake's body mass by 60%. In another series of the experiments, we showed that infusion of amino acids directly into the stomach or the intestine elicited similar metabolic responses. This indicates a lower gastric contribution to the SDA response than previously reported. To include an assessment of the gastric contribution to the postprandial cardiovascular response, we also measured blood and heart rate. While heart rate increased during digestion in snakes with pyloric blockade, there was no rise in the double-blocked heart rates compared to fasting controls. Thus, the non-adrenergic-non-cholinergic factor that stimulates heart rate during digestion does not stem from the stomach. Finally, there was no growth of the visceral organs in response to digestion when chyme was prevented from reaching the intestine. Copyright © 2013 Elsevier Inc. All rights reserved.

  15. Effect of salinity changes on the bacterial diversity, photosynthesis and oxygen consumption of cyanobacterial mats from an intertidal flat of the Arabian Gulf.

    Science.gov (United States)

    Abed, Raeid M M; Kohls, Katharina; de Beer, Dirk

    2007-06-01

    The effects of salinity fluctuation on bacterial diversity, rates of gross photosynthesis (GP) and oxygen consumption in the light (OCL) and in the dark (OCD) were investigated in three submerged cyanobacterial mats from a transect on an intertidal flat. The transect ran 1 km inland from the low water mark along an increasingly extreme habitat with respect to salinity. The response of GP, OCL and OCD in each sample to various salinities (65 per thousand, 100 per thousand, 150 per thousand and 200 per thousand) were compared. The obtained sequences and the number of unique operational taxonomic units showed clear differences in the mats' bacterial composition. While cyanobacteria decreased from the lower to the upper tidal mat, other bacterial groups such as Chloroflexus and Cytophaga/Flavobacteria/Bacteriodetes showed an opposite pattern with the highest dominance in the middle and upper tidal mats respectively. Gross photosynthesis and OCL at the ambient salinities of the mats decreased from the lower to the upper tidal zone. All mats, regardless of their tidal location, exhibited a decrease in areal GP, OCL and OCD rates at salinities > 100 per thousand. The extent of inhibition of these processes at higher salinities suggests an increase in salt adaptation of the mats microorganisms with distance from the low water line. We conclude that the resilience of microbial mats towards different salinity regimes on intertidal flats is accompanied by adjustment of the diversity and function of their microbial communities.

  16. Retinoic acid-induced differentiation increases the rate of oxygen consumption and enhances the spare respiratory capacity of mitochondria in SH-SY5Y cells.

    Science.gov (United States)

    Xun, Zhiyin; Lee, Do-Yup; Lim, James; Canaria, Christie A; Barnebey, Adam; Yanonne, Steven M; McMurray, Cynthia T

    2012-04-01

    Retinoic acid (RA) is used in differentiation therapy to treat a variety of cancers including neuroblastoma. The contributing factors for its therapeutic efficacy are poorly understood. However, mitochondria (MT) have been implicated as key effectors in RA-mediated differentiation process. Here we utilize the SH-SY5Y human neuroblastoma cell line as a model to examine how RA influences MT during the differentiation process. We find that RA confers an approximately sixfold increase in the oxygen consumption rate while the rate of glycolysis modestly increases. RA treatment does not increase the number of MT or cause measurable changes in the composition of the electron transport chain. Rather, RA treatment significantly increases the mitochondrial spare respiratory capacity. We propose a competition model for the therapeutic effects of RA. Specifically, the high metabolic rate in differentiated cells limits the availability of metabolic nutrients for use by the undifferentiated cells and suppresses their growth. Thus, RA treatment provides a selective advantage for the differentiated state. Published by Elsevier Ireland Ltd.

  17. The effect of short-term dimethylglycine treatment on oxygen consumption in cytochrome oxidase deficiency: a double-blind randomized crossover clinical trial.

    Science.gov (United States)

    Liet, Jean-Michel; Pelletier, Véronique; Robinson, Brian H; Laryea, Maurice D; Wendel, Udo; Morneau, Sylvain; Morin, Charles; Mitchell, Grant; Lacroix, Jacques

    2003-01-01

    To study the effectiveness of dimethylglycine (DMG) on oxygen consumption (VO(2)) in children with Saguenay-Lac-Saint-Jean cytochrome-c oxidase (SLSJ-COX) deficiency (OMIM 220111). In a crossover randomized double-blind clinical trial, 5 children with SLSJ-COX deficiency, who were stable and old enough to comply with VO(2) measurement, were treated with placebo or DMG for 3 days, and with the alternate treatment after a 2-week washout period. VO(2) was measured by indirect calorimetry before and after treatment. Dietary caloric intake was calculated for 3 days before each measurement. Mean caloric intakes per day were 1562 and 1342 kcal x m(-2) before and during placebo, 1,336 and 1,380 before and during DMG, respectively. DMG was well tolerated and, in all cases, resulted in markedly increased blood DMG levels (617 + 203 mmol x L(-1)), versus 0 to 2 mmol x L(-1) without treatment. Mean VO(2) was lower after administration of either DMG (-1 +/- 3 mL x min(-1) x m(-2)) or placebo (-6 +/- 4), but neither difference was statistically significant. There was no detectable effect of DMG treatment on blood levels of lactate, pyruvate, bicarbonate, or pH. VO(2) values of patients (range, 101-135 mL x min(-1) x m(-2)) were lower than published norms (150-160 mL x min(-1) x m(-2)). This study suggests that treatment with DMG does not substantially change VO(2) in children with SLSJ-COX deficiency.

  18. Do Overweight and Obese Individuals Select a “Moderate Intensity” Workload When Asked to Do So?

    Directory of Open Access Journals (Sweden)

    Cameron W. Hall

    2012-01-01

    Full Text Available The purpose of this study was (1 to determine if overweight/obese individuals (age 26–50 y would self-select moderate exercise intensity when asked to do so and (2 to determine how this self-selected workload compared to exercising at a workload (60% peak aerobic capacity that is known to provide cardioprotective health benefits. Oxygen consumption (VO2 and energy expenditure were measured in 33 men/women (BMI≥27 kg/m2 who completed two 30 min walking bouts: (1 self-selected walking pace on an indoor track and (2 prescribed exercise pace (60% VO2 peak on a treadmill. The data revealed that (1 the prescribed intensity was 6% higher than the self-selected pace and elicited a higher energy expenditure (<0.05 than the self-selected pace (+83 kJ; (2 overweight subjects walked at a slightly lower percentage of VO2 peak than the obese subjects (<0.05; (3 men walked at a lower percentage of VO2 peak than the women (<0.05. In conclusion when asked to walk at a moderate intensity, overweight/obese individuals tended to select a lower workload in the “moderate intensity” range which could be maintained for 30 min; however, a higher intensity which would be more cardioprotective could not be maintained for 30 min by most individuals.

  19. Statins are related to impaired exercise capacity in males but not females.

    Science.gov (United States)

    Bahls, Martin; Groß, Stefan; Ittermann, Till; Busch, Raila; Gläser, Sven; Ewert, Ralf; Völzke, Henry; Felix, Stephan B; Dörr, Marcus

    2017-01-01

    Exercise and statins reduce cardiovascular disease (CVD). Exercise capacity may be assessed using cardiopulmonary exercise testing (CPET). Whether statin medication is associated with CPET parameters is unclear. We investigated if statins are related with exercise capacity during CPET in the general population. Cross-sectional data of two independent cohorts of the Study of Health in Pomerania (SHIP) were merged (n = 3,500; 50% males). Oxygen consumption (VO2) at peak exercise (VO2peak) and anaerobic threshold (VO2@AT) was assessed during symptom-limited CPET. Two linear regression models related VO2peak with statin usage were calculated. Model 1 adjusted for age, sex, previous myocardial infarction, and physical inactivity and model 2 additionally for body mass index, smoking, hypertension, diabetes and estimated glomerular filtration rate. Propensity score matching was used for validation. Statin usage was associated with lower VO2peak (no statin: 2336; 95%-confidence interval [CI]: 2287-2,385 vs. statin 2090; 95%-CI: 2,031-2149 ml/min; P exercise capacity in males but not females. Sex specific effects of statins on cardiopulmonary exercise capacity deserve further research.

  20. Skeletal muscle mass and exercise performance in stable ambulatory patients with heart failure.

    Science.gov (United States)

    Lang, C C; Chomsky, D B; Rayos, G; Yeoh, T K; Wilson, J R

    1997-01-01

    The purpose of this study was to determine whether skeletal muscle atrophy limits the maximal exercise capacity of stable ambulatory patients with heart failure. Body composition and maximal exercise capacity were measured in 100 stable ambulatory patients with heart failure. Body composition was assessed by using dual-energy X-ray absorption. Peak exercise oxygen consumption (VO2peak) and the anaerobic threshold were measured by using a Naughton treadmill protocol and a Medical Graphics CardioO2 System. VO2peak averaged 13.4 +/- 3.3 ml.min-1.kg-1 or 43 +/- 12% of normal. Lean body mass averaged 52.9 +/- 10.5 kg and leg lean mass 16.5 +/- 3.6 kg. Leg lean mass correlated linearly with VO2peak (r = 0.68, P < 0.01), suggesting that exercise performance is influences by skeletal muscle mass. However, lean body mass was comparable to levels noted in 1,584 normal control subjects, suggesting no decrease in muscle mass. Leg muscle mass was comparable to levels noted in 34 normal control subjects, further supporting this conclusion. These findings suggest that exercise intolerance in stable ambulatory patients with heart failure is not due to skeletal muscle atrophy.

  1. Cardiorespiratory fitness of a Brazilian regional sample distributed in different tables.

    Science.gov (United States)

    Belli, Karlyse Claudino; Callegaro, Carine C; Calegaro, Carine; Richter, Cleusa Maria; Klafke, Jonatas Zeni; Stein, Ricardo; Viecili, Paulo Ricardo Nazario

    2012-09-01

    Most classification tables of cardiorespiratory fitness (CRF) used in clinical practice are international and have not been validated for the Brazilian population. That can result in important discrepancies when that classification is extrapolated to our population. To assess the use of major CRF tables available in a Brazilian population sample of the Central High Plan of the state of Rio Grande do Sul (RS). This study assessed the retrospective data of 2,930 individuals, living in 36 cities of the Central High Plan of the state of RS, and considered the following: presence of risk factors for cardiovascular disease and estimated maximum oxygen consumption (VO2peak) values obtained through exercise test with Bruce protocol. To classify CRF, the individuals were distributed according to sex, inserted in their respective age groups in the Cooper, American Heart Association (AHA) and Universidade Federal de São Paulo (Unifesp) tables, and classified according to their VO2peak. Women had lower VO2peak values as compared with those of men (23.5 ± 8.5 vs. 31.7 ± 10.8 mL.kg-1.min-1, p Unifesp x AHA). Our findings indicate important discrepancy in the CRF classification levels of the tables assessed. Future studies could assess whether international tables could be used for the Brazilian population and populations of different regions of Brazil.

  2. The influence of ascorbic acid on the oxygen consumption and the heat production by the cells of wheat seedling roots with their mitochondrial electron transport chain inhibited at complexes I and III

    International Nuclear Information System (INIS)

    Gordon, L.K.; Rakhmatullina, D.F.; Ogorodnikova, T.I.; Alyabyev, A.J.; Minibayeva, F.V.; Loseva, N.L.; Mityashina, S.Y.

    2007-01-01

    The influence of exogenous ascorbic acid (AsA) on oxidative phosphorylation was studied using wheat seedling roots. Treatment of them with AsA stimulated the rates of oxygen consumption and the heat production and caused a decrease of the respiratory coefficient. The increase in respiration was prevented by inhibitors of ascorbate oxidase, diethyldithiocarbamate (DEDTC), and of cytochrome oxidase, cyanide (KCN). Exogenous AsA sharply stimulated the rate of oxygen consumption of roots when complexes I and III of the mitochondrial electron transport chain were inhibited by rotenone and antimycin A, respectively, while the rates of heat production did not change significantly. It is concluded that AsA is a potent energy substrate, which can be used in conditions of failing I and III complexes in the mitochondrial electron transport chain

  3. Effect of race distance on muscle oxygenation in short-track speed skating.

    Science.gov (United States)

    Hesford, Catherine M; Laing, Stewart; Cardinale, Marco; Cooper, Chris E

    2013-01-01

    Previous work identified an asymmetry in tissue desaturation changes in the left and right quadriceps muscles during on-ice skating at maximal speed in males. The effect of changing race distance on the magnitude of desaturation or leg asymmetry is unknown. Six elite male skaters (age = 23 ± 1.8 yr, height = 1.8 ± 0.1 m, mass = 80.1 ± 5.7 kg, midthigh skinfold thickness = 7 ± 2 mm) and four elite female skaters (age = 21 ± 4 yr, height = 1.6 ± 0.1 m, mass = 65.2 ± 4.3 kg, midthigh skinfold thickness = 10 ± 1 mm) were studied. Subjects completed time trials over three race distances. Blood lactate concentration and O2 uptake measurements were combined with near-infrared spectroscopy measures of muscle oxygenation (TSI) and blood volume (tHb) in the right and left vastus lateralis. Neither race distance nor gender had a significant effect on the magnitude of maximal muscle desaturation (ΔTSI(max)). Pattern of local changes in tHb during individual laps was dependent upon subtle differences in skating technique used for the different race distances. Linear regression analysis revealed asymmetry between the right and left leg desaturation in males during the final stages of each race distance, but not in females. At all race distances, local muscle desaturation reached maximal values much more quickly than global VO(2peak). The use of wearable near-infrared spectroscopy devices enabled measurement of muscle oxygenation during competitive race simulation, thus providing unique insight into the effects of velocity and technique changes on local muscle oxygenation. This may have implications for training and race pacing in speed skating.

  4. Maximal cardiorespiratory fitness testing in individuals with chronic stroke with cognitive impairment: practice test effects and test-retest reliability.

    Science.gov (United States)

    Olivier, Charles; Doré, Jean; Blanchet, Sophie; Brooks, Dina; Richards, Carol L; Martel, Guy; Robitaille, Nancy-Michelle; Maltais, Désirée B

    2013-11-01

    To evaluate, for individuals with chronic stroke with cognitive impairment, (1) the effects of a practice test on peak cardiorespiratory fitness test results; (2) cardiorespiratory fitness test-retest reliability; and (3) the relationship between individual practice test effects and cognitive impairment. Cross-sectional. Rehabilitation center. A convenience sample of 21 persons (men [n=12] and women [n=9]; age range, 48-81y; 44.9±36.2mo poststroke) with cognitive impairments who had sufficient lower limb function to perform the test. Not applicable. Peak oxygen consumption (Vo(2)peak, ml·kg(-1)·min(-1)). Test-retest reliability of Vo(2)peak was excellent (intraclass correlation coefficient model 2,1 [ICC2,1]=.94; 95% confidence interval [CI], .86-.98). A paired t test showed that there was no significant difference for the group for Vo(2)peak obtained from 2 symptom-limited cardiorespiratory fitness tests performed 1 week apart on a semirecumbent cycle ergometer (test 2-test 1 difference, -.32ml·kg(-1)·min(-1); 95% CI, -.69 to 1.33ml·kg(-1)·min(-1); P=.512). Individual test-retest differences in Vo(2)peak were, however, positively related to general cognitive function as measured by the Mini-Mental State Examination (ρ=.485; Preliably measured in this group without a practice test. General cognitive function, however, may influence the effect of a practice test in that those with lower general cognitive function appear to respond differently to a practice test than those with higher cognitive function. Copyright © 2013 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  5. Critical windows in embryonic development: Shifting incubation temperatures alter heart rate and oxygen consumption of Lake Whitefish (Coregonus clupeaformis) embryos and hatchlings.

    Science.gov (United States)

    Eme, J; Mueller, C A; Manzon, R G; Somers, C M; Boreham, D R; Wilson, J Y

    2015-01-01

    Critical windows are periods of developmental susceptibility when the phenotype of an embryonic, juvenile or adult animal may be vulnerable to environmental fluctuations. Temperature has pervasive effects on poikilotherm physiology, and embryos are especially vulnerable to temperature shifts. To identify critical windows, we incubated whitefish embryos at control temperatures of 2°C, 5°C, or 8°C, and shifted treatments among temperatures at the end of gastrulation or organogenesis. Heart rate (fH) and oxygen consumption ( [Formula: see text] ) were measured across embryonic development, and [Formula: see text] was measured in 1-day old hatchlings. Thermal shifts, up or down, from initial incubation temperatures caused persistent changes in fH and [Formula: see text] compared to control embryos measured at the same temperature (2°C, 5°C, or 8°C). Most prominently, when embryos were measured at organogenesis, shifting incubation temperature after gastrulation significantly lowered [Formula: see text] or fH. Incubation at 2°C or 5°C through gastrulation significantly lowered [Formula: see text] (42% decrease) and fH (20% decrease) at 8°C, incubation at 2°C significantly lowered [Formula: see text] (40% decrease) and fH (30% decrease) at 5°C, and incubation at 5°C and 8°C significantly lowered [Formula: see text] at 2°C (27% decrease). Through the latter half of development, [Formula: see text] and fH in embryos were not different from control values for thermally shifted treatments. However, in hatchlings measured at 2°C, [Formula: see text] was higher in groups incubated at 5°C or 8°C through organogenesis, compared to 2°C controls (43 or 65% increase, respectively). Collectively, these data suggest that embryonic development through organogenesis represents a critical window of embryonic and hatchling phenotypic plasticity. This study presents an experimental design that identified thermally sensitive periods for fish embryos. Crown Copyright

  6. The effect of adrenaline and high Ca2+ on the mechanical performance and oxygen consumption of the isolated perfused trout (Oncorhynchus mykiss) heart

    DEFF Research Database (Denmark)

    Rytter, Dorte; Gesser, Hans

    2007-01-01

    In heart muscle from mammals, catecholamines frequently evoke an oxygen waste and reduce efficiency. It was examined if this also applies to fish in which heart muscle activity is often restricted by oxygen availability. In the isolated perfused heart from rainbow trout, adrenaline (0.5 micro...

  7. Post-ischaemic changes in the response time of oxygen consumption to demand in the isolated rat heart are mediated partly by calcium and glycolysis

    NARCIS (Netherlands)

    Zuurbier, C. J.; Ince, C.

    2002-01-01

    This study examined whether different durations of ischaemia (I) and reperfusion (R) altered the kinetics of O-2 consumption-to-demand matching and the contribution of changes in calcium and metabolic pathways to possible alterations. The response time of mitochondrial O-2 consumption (t(mito)) to a

  8. Water flow requirements related to oxygen consumption in juveniles of Oplegnathus insignis Requerimientos de flujo de agua en función del consumo de oxígeno en juveniles de Oplegnathus insignis

    Directory of Open Access Journals (Sweden)

    Elio Segovia

    2012-09-01

    Full Text Available In this study the oxygen consumption rate in four groups of Oplegnathus insignis was examined under three different water temperatures 13, 18 and 23°C. Average weight of each group of fish was 9.5, 198, 333 and 525 g respectively. Oxygen consumption was measured in a respirometer of 18.8 L capacity and results show that at the same water temperature occurs an inverse relationship between body weight and oxygen consumption whereas for same body weight (W in kg the respiration rate varies proportionally with temperature rise (T in °C. The generalized equation of oxygen consumption (Ro in routine metabolism was determined as: Ro (mg O2 kg-1 h-1 = [85.229 + (10.03 T]-(221.344 W. The information it is analized with regard to establishing quantitative relationships that allow a more precise specification of the water flow requirements and renewal rates in open flow systems without oxygenation, considering aspects such as body weight, respiratory rate, temperature and stocking density.Se determinó la tasa de consumo de oxígeno de Oplegnathus insignis en cuatro grupos de peces bajo tres temperaturas diferentes: 13, 18 y 23°C. El peso promedio de cada grupo de peces fue de 9,5, 198, 333 y 523 g respectivamente. El consumo de oxígeno se determinó en un respirómetro de 18,8 L de capacidad y los resultados muestran que a una misma temperatura ocurre una relación inversa entre el peso corporal (W en kg y el consumo de oxígeno, mientras que para un mismo peso corporal la tasa respiratoria varía proporcionalmente con el ascenso de temperatura (T en °C. La ecuación generalizada que representa el consumo de oxígeno (Ro en metabolismo de rutina se determinó como: Ro (mg O2 kg-1 h-1 = [85.229 + (10.03 T]-(221.344 W. Se analizó la información en relación a establecer las relaciones cuantitativas que permitan una especificación más exacta de los requerimientos de flujo de agua y tasas de renovación en sistemas de flujo abierto y sin oxigenaci

  9. Oxygen (average seabed consumption) data collected using pressure gauge from the Drake Passage in part of the International Decade of Ocean Exploration / International Southern Ocean Studies / First Dynamic Response and Kinematics Experiment in the Drake Passage from 1976-02-08 to 1982-03-19 (NODC Accession 9000027)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Oxygen (average seabed consumption) data were collected using pressure gauge from the Drake Passage from February 8, 1976 to March 19, 1982. Data were submitted by...

  10. Bcl-xL-mediated remodeling of rod and cone synaptic mitochondria after postnatal lead exposure: electron microscopy, tomography and oxygen consumption.

    Science.gov (United States)

    Perkins, Guy A; Scott, Ray; Perez, Alex; Ellisman, Mark H; Johnson, Jerry E; Fox, Donald A

    2012-01-01

    Postnatal lead exposure produces rod-selective and Bax-mediated apoptosis, decreased scotopic electroretinograms (ERGs), and scotopic and mesopic vision deficits in humans and/or experimental animals. Rod, but not cone, inner segment mitochondria were considered the primary site of action. However, photoreceptor synaptic mitochondria were not examined. Thus, our experiments investigated the structural and functional effects of environmentally relevant postnatal lead exposure on rod spherule and cone pedicle mitochondria and whether Bcl-xL overexpression provided neuroprotection. C57BL/6N mice pups were exposed to lead only during lactation via dams drinking water containing lead acetate. The blood [Pb] at weaning was 20.6±4.7 µg/dl, which decreased to the control value by 2 months. To assess synaptic mitochondrial structural differences and vulnerability to lead exposure, wild-type and transgenic mice overexpressing Bcl-xL in photoreceptors were used. Electron microscopy, three-dimensional electron tomography, and retinal and photoreceptor synaptic terminal oxygen consumption (QO(2)) studies were conducted in adult control, Bcl-xL, lead, and Bcl-xL/lead mice. The spherule and pedicle mitochondria in lead-treated mice were swollen, and the cristae structure was markedly changed. In the lead-treated mice, the mitochondrial cristae surface area and volume (abundance: measure correlated with ATP (ATP) synthesis) were decreased in the spherules and increased in the pedicles. Pedicles also had an increased number of crista segments per volume. In the lead-treated mice, the number of segments/crista and fraction of cristae with multiple segments (branching) similarly increased in spherule and pedicle mitochondria. Lead-induced remodeling of spherule mitochondria produced smaller cristae with more branching, whereas pedicle mitochondria had larger cristae with more branching and increased crista junction (CJ) diameter. Lead decreased dark- and light-adapted photoreceptor

  11. Effect of membranes on oxygen transfer rate and consumption within a newly developed three-compartment bioartificial liver device: Advanced experimental and theoretical studies.

    Science.gov (United States)

    Hilal-Alnaqbi, Ali; Mourad, Abdel-Hamid I; Yousef, Basem F

    2014-01-01

    A mathematical model is developed to predict oxygen transfer in the fiber-in-fiber (FIF) bioartificial liver device. The model parameters are taken from the constructed and tested FIF modules. We extended the Krogh cylinder model by including one more zone for oxygen transfer. Cellular oxygen uptake was based on Michaelis-Menten kinetics. The effect of varying a number of important model parameters is investigated, including (1) oxygen partial pressure at the inlet, (2) the hydraulic permeability of compartment B (cell region), (3) the hydraulic permeability of the inner membrane, and (4) the oxygen diffusivity of the outer membrane. The mathematical model is validated by comparing its output against the experimentally acquired values of an oxygen transfer rate and the hydrostatic pressure drop. Three governing simultaneous linear differential equations are derived to predict and validate the experimental measurements, e.g., the flow rate and the hydrostatic pressure drop. The model output simulated the experimental measurements to a high degree of accuracy. The model predictions show that the cells in the annulus can be oxygenated well even at high cell density or at a low level of gas phase PG if the value of the oxygen diffusion coefficient Dm is 16 × 10(-5) . The mathematical model also shows that the performance of the FIF improves by increasing the permeability of polypropylene membrane (inner fiber). Moreover, the model predicted that 60% of plasma has access to the cells in the annulus within the first 10% of the FIF bioreactor axial length for a specific polypropylene membrane permeability and can reach 95% within the first 30% of its axial length. © 2013 International Union of Biochemistry and Molecular Biology, Inc.

  12. Effects of exercise mode on the peak oxygen uptake and blood lactate response in boys aged 11-12 years

    Directory of Open Access Journals (Sweden)

    Fabiana Andrade Machado

    2006-09-01

    Full Text Available The objective of this study was to analyze the effects of exercise mode (running x cycling on the indexesrelated to aerobic fitness (VO2peak and blood lactate response to exercise in children. Participated of this study 20 active boys apparently healthy (age = 11.48 + 0.41 yr.; body mass = 41.38 + 10.45 kg; stature = 147.45 + 6.56 cm, with sexual maturational level 1 and 2 (pubic hair, which performed two incremental tests, with stages of 3 minutes until voluntary exhaustion, in treadmill (TR and cycle ergometer (CE, to the determination of peak oxygen uptake (VO2peak and lactate threshold (LT. The VO2peak was determined through the higher value obtained at intervals of 15 seconds. The LT was determined as the exercise intensity where the first and sustained increase of blood lactate above rest level occurred. The VO2peak (45.16 + 5.98 x 42.93 + 7.51 ml/kg/min, maximal heart rate (196.5 + 6.98 x 187.3 + 9.27 bpm, VO2 at LL (31.82 + 10.09 x 25.19 + 7.36 ml/kg/min and HR at LL (150.5 + 17.75 x 131.3 + 12.98 bpm were significantly higher in TR than CE, respectively. Thus, similar to adults, boys of 11 to 12 years present higher aerobic indexes (submaximal and maximal in running than cycling, which can haveimportant implications for healthy professionals that utilize exercise for the healthy promotion, rehabilitation and experimental designs. RESUMO O objetivo deste estudo foi analisar os efeitos do modo de exercício (corrida x ciclismo sobre os índices relacionados com a aptidão aeróbia (VO2pico e resposta de lactato ao exercício em crianças. Participaram doestudo 20 meninos, aparentemente saudáveis e ativos (idade = 11,48 + 0,41 anos; massa corporal = 41,38 + 10,45 kg; estatura = 147,45 + 6,56 cm, com níveis de maturação sexual 1 e 2 (pilosidade pubiana, que realizaram dois testes incrementais, com estágios de 3 minutos até a exaustão voluntária, em esteira rolante (ER e bicicleta ergométrica (BE, para a determinação do pico do

  13. Acute Consumption of Bordo Grape Juice and Wine Improves Serum Antioxidant Status in Healthy Individuals and Inhibits Reactive Oxygen Species Production in Human Neuron-Like Cells.

    Science.gov (United States)

    Copetti, Cristiane; Franco, Fernanda Wouters; Machado, Eduarda da Rosa; Soquetta, Marcela Bromberger; Quatrin, Andréia; Ramos, Vitor de Miranda; Moreira, José Cláudio Fonseca; Emanuelli, Tatiana; Sautter, Cláudia Kaehler; Penna, Neidi Garcia

    2018-01-01

    Few studies investigated the biological effects of American grape cultivars. We investigated the metabolic response after acute consumption of grape juice or wine from Bordo grapes ( Vitis labrusca ) in a placebo-controlled crossover study with fifteen healthy volunteers. Blood samples were collected 1 hour after the intake of 100 mL of water, juice, or wine to measure TBARS, ABTS, FRAP, glucose, and uric acid levels. To evaluate differences in cellular response, intracellular reactive species production (DCFH-DA) and metabolic mitochondrial viability (MTT) were assessed after exposure of human neuron-like cells (SH-SY5Y) to juice or wine. Glycemia was reduced after juice or wine consumption, whereas blood levels of uric acid were reduced after juice consumption but increased after wine consumption. Juice and wine consumption reduced plasma lipid peroxidation and increased plasma antioxidant capacity (ABTS and FRAP assays). Furthermore, juice inhibited H 2 O 2 -induced intracellular production of reactive species (RS) and increased the viability of SH-SY5Y cells. In contrast, wine (dealcoholized) exhibited a per se effect by inducing the production of RS and reducing cell viability. These results indicate a positive impact of acute consumption of Bordo juice and wine on human oxidative status, whereas only juice had protective effects against oxidative stress-induced cytotoxicity.

  14. Acute Consumption of Bordo Grape Juice and Wine Improves Serum Antioxidant Status in Healthy Individuals and Inhibits Reactive Oxygen Species Production in Human Neuron-Like Cells

    Directory of Open Access Journals (Sweden)

    Cristiane Copetti

    2018-01-01

    Full Text Available Few studies investigated the biological effects of American grape cultivars. We investigated the metabolic response after acute consumption of grape juice or wine from Bordo grapes (Vitis labrusca in a placebo-controlled crossover study with fifteen healthy volunteers. Blood samples were collected 1 hour after the intake of 100 mL of water, juice, or wine to measure TBARS, ABTS, FRAP, glucose, and uric acid levels. To evaluate differences in cellular response, intracellular reactive species production (DCFH-DA and metabolic mitochondrial viability (MTT were assessed after exposure of human neuron-like cells (SH-SY5Y to juice or wine. Glycemia was reduced after juice or wine consumption, whereas blood levels of uric acid were reduced after juice consumption but increased after wine consumption. Juice and wine consumption reduced plasma lipid peroxidation and increased plasma antioxidant capacity (ABTS and FRAP assays. Furthermore, juice inhibited H2O2-induced intracellular production of reactive species (RS and increased the viability of SH-SY5Y cells. In contrast, wine (dealcoholized exhibited a per se effect by inducing the production of RS and reducing cell viability. These results indicate a positive impact of acute consumption of Bordo juice and wine on human oxidative status, whereas only juice had protective effects against oxidative stress-induced cytotoxicity.

  15. High oxygen consumption rates and scale loss indicate elevated aggressive behaviour at low rearing density, while elevated brain serotonergic activity suggest chronic stress at high rearing densities in farmed rainbow trout Oncorhynchus mykiss

    DEFF Research Database (Denmark)

    Laursen, Danielle Caroline; Silva, P.I.M.; Larsen, Bodil Katrine

    2013-01-01

    of a previous study,where levels of crowding where determined using the spatial distribution of fish in two-tank systems. An un-crowded low density of 25 kg m−3, the highest density accepted by the fish without showing indications of crowding stress of 80 kg m−3 as the intermediate density, and the highest...... density accepted by the fish showing indications of crowding stress of 140 kg m−3 as the high density were investigated. The aimof the present study was to examine the effect of being held at these densities on indicators of welfare. This was achieved through oxygen consumption measurements using...

  16. The Andersen aerobic fitness test

    DEFF Research Database (Denmark)

    Aadland, Eivind; Terum, Torkil; Mamen, Asgeir

    2014-01-01

    BACKGROUND: High aerobic fitness is consistently associated with a favorable metabolic risk profile in children. Direct measurement of peak oxygen consumption (VO2peak) is often not feasible, thus indirect tests such as the Andersen test are required in many settings. The present study seeks...... of agreement) were 26.7±125.2 m for test 2 vs. test 1 (pfit in the present sample; thus, we suggest a new equation: VO2peak = 23....... Researchers should be aware of the amount of noise in indirect tests that estimate aerobic fitness....

  17. Oxygen consumption and cytochrome exidase activity of axolotl limbs muscle tissue in restoration of regenerative ability suprressed by X-irradiation

    International Nuclear Information System (INIS)

    Teplits, N.A.

    1975-01-01

    The rate of oxygen use and activity of cytochrome oxidase in a homogenate of mitochondria and nuclei of muscle tissue of axolotl limbs after suppression of their regenerative capability by x irradiation and their restoration was studied experimentally. With suppression of the regenative capability the use of oxygen was depressed. Cytochrome oxidase activity in the homogenate and mitochondria decreased compared to that of the intact limb, in the nuclei of muscle tissue it was the same or greater. With restoration of the regenerative capability of the limbs the respiration rate of the homogenate and the mitochondria increased, accompanied by increased cytochrome oxidase activity. In the nuclei the cytochrome oxidase activity did not change in the blastema stage and sharply decreased in the limb formation state. (E.T.)

  18. Oxygen consumption and cytochrome exidase activity of axolotl limbs muscle tissue in restoration of regenerative ability suppressed by X-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Teplits, N A [AN SSSR, Moscow. Inst. Biologii Razvitiya

    1975-01-01

    The rate of oxygen use and activity of cytochrome oxidase in a homogenate of mitochondria and nuclei of muscle tissue of axolotl limbs after suppression of their regenerative capability by x irradiation and their restoration was studied experimentally. With suppression of the regenative capability the use of oxygen was depressed. Cytochrome oxidase activity in the homogenate and mitochondria decreased compared to that of the intact limb, in the nuclei of muscle tissue it was the same or greater. With restoration of the regenerative capability of the limbs the respiration rate of the homogenate and the mitochondria increased, accompanied by increased cytochrome oxidase activity. In the nuclei the cytochrome oxidase activity did not change in the blastema stage and sharply decreased in the limb formation state.

  19. Characterization of sludge properties for sewage treatment in a practical-scale down-flow hanging sponge reactor: oxygen consumption and removal of organic matter, ammonium, and sulfur.

    Science.gov (United States)

    Nomoto, Naoki; Hatamoto, Masashi; Ali, Muntjeer; Jayaswal, Komal; Iguchi, Akinori; Okubo, Tsutomu; Takahashi, Masanobu; Kubota, Kengo; Tagawa, Tadashi; Uemura, Shigeki; Yamaguchi, Takashi; Harada, Hideki

    2018-02-01

    The characteristics of sludge retained in a down-flow hanging sponge reactor were investigated to provide a better understanding of the sewage treatment process in the reactor. The organic removal and sulfur oxidation conditions were found to differ between the first layer and the following three layers. It was found that 63% and 59% of the organic matter was removed in the first layer, even though the hydraulic retention time was only 0.2 h. It is thought that the organic removal resulted from aerobic and anaerobic biodegradation on the sponge medium. The sulfate concentration increased 1.5-1.9-fold in the first layer, with almost no subsequent change in the second to fourth layers. It was shown that oxidation of sulfide in the influent was completed in the first layer. The result of the oxygen uptake rate test with an ammonium nitrogen substrate suggested that the ammonium oxidation rate was affected by the condition of dissolved oxygen (DO) or oxidation-reduction potential (ORP).

  20. GABAA Receptor-Mediated Bidirectional Control of Synaptic Activity, Intracellular Ca2+, Cerebral Blood Flow, and Oxygen Consumption in Mouse Somatosensory Cortex In Vivo

    DEFF Research Database (Denmark)

    Jessen, Sanne Barsballe; Brazhe, Alexey; Lind, Barbara Lykke

    2015-01-01

    Neural activity regulates local increases in cerebral blood flow (ΔCBF) and the cortical metabolic rate of oxygen (ΔCMRO2) that constitutes the basis of BOLD functional neuroimaging signals. Glutamate signaling plays a key role in brain vascular and metabolic control; however, the modulatory effect...... of GABA is incompletely understood. Here we performed in vivo studies in mice to investigate how THIP (which tonically activates extrasynaptic GABAARs) and Zolpidem (a positive allosteric modulator of synaptic GABAARs) impact stimulation-induced ΔCBF, ΔCMRO2, local field potentials (LFPs), and fluorescent...... cytosolic Ca2+ transients in neurons and astrocytes. Low concentrations of THIP increased ΔCBF and ΔCMRO2 at low stimulation frequencies. These responses were coupled to increased synaptic activity as indicated by LFP responses, and to Ca2+ activities in neurons and astrocytes. Intermediate and high...

  1. Oxygen consumption of Litopenaeus vannamei juveniles in heterotrophic medium with zero water exchange Consumo de oxigênio de juvenis de Litopenaeus vannamei em meio heterotrófico sem renovação de água

    Directory of Open Access Journals (Sweden)

    Luis Vinatea

    2009-05-01

    Full Text Available This work aimed at determining the dissolved oxygen consumption rate of Litopenaeus vannamei juveniles maintained in a microbial biofloc raceway system at high density with no aeration. Three 4 L bottles were filled for each treatment, sealed hermetically, and placed in an enclosed greenhouse raceway system. Four shrimp (13.2±1.42 g were assigned to two sets of the bottles, which underwent the following treatments: light conditions with no shrimp; dark conditions with no shrimp; light conditions with shrimp; and dark conditions with shrimp. Dissolved oxygen content was measured every 10 min for 30 min. A quadratic behavior was observed in dissolved oxygen concentration over time. Significant differences for oxigen consumption were observed only at 10 and 20 min between shrimp maintained in the dark and those under light conditions. At 10 min, a higher value was observed in shrimp maintained under light, and at 20 min, in the dark. Significant differences between 10 and 20 min and between 10 and 30 min were observed when oxygen consumption was analyzed over time in the presence of light. Under dark conditions there were significant differences only between 20 and 30 min. Lethal oxygen concentration (0.65 mg L-1 would be reached in less than one hour either under light or dark conditions with no aeration.O objetivo deste trabalho foi determinar o consumo de oxigênio dissolvido (OD de juvenis de Litopenaeus vannamei mantidos em sistema de cultivo de bioflocs bacterianos em alta densidade e ausência de aeração. Três garrafas de 4 L foram preenchidas para cada tratamento, fechadas hermeticamente e colocadas em sistema de cultivo fechado. Quatro camarões (13,2±1,42 g foram colocados em dois dos conjuntos de garrafas. Os tratamentos aplicados foram: luminosidade, sem camarões; escuro, sem camarões; luminosidade, com camarões; escuro, com camarões. A concentração de oxigênio dissolvido foi determinada a cada 10 min durante 30 min. Foi

  2. The effects of four weeks of creatine supplementation and high-intensity interval training on cardiorespiratory fitness: a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Cramer Joel T

    2009-11-01

    Full Text Available Abstract Background High-intensity interval training has been shown to be a time-efficient way to induce physiological adaptations similar to those of traditional endurance training. Creatine supplementation may enhance high-intensity interval training, leading to even greater physiological adaptations. The purpose of this study was to determine the effects of high-intensity interval training (HIIT and creatine supplementation on cardiorespiratory fitness and endurance performance (maximal oxygen consumption (VO2PEAK, time-to-exhaustion (VO2PEAKTTE, ventilatory threshold (VT, and total work done (TWD in college-aged men. Methods Forty-three recreationally active men completed a graded exercise test to determine VO2PEAK, VO2PEAKTTE, and VT. In addition, participants completed a time to exhaustion (TTE ride at 110% of the maximum workload reached during the graded exercise test to determine TWD (TTE (sec × W = J. Following testing, participants were randomly assigned to one of three groups: creatine (creatine citrate (Cr; n = 16, placebo (PL; n = 17, or control (n = 10 groups. The Cr and PL groups completed four weeks of HIIT prior to post-testing. Results Significant improvements in VO2PEAK and VO2PEAKTTE occurred in both training groups. Only the Cr group significantly improved VT (16% vs. 10% improvement in PL. No changes occurred in TWD in any group. Conclusion In conclusion, HIIT is an effective and time-efficient way to improve maximal endurance performance. The addition of Cr improved VT, but did not increase TWD. Therefore, 10 g of Cr per day for five days per week for four weeks does not seem to further augment maximal oxygen consumption, greater than HIIT alone; however, Cr supplementation may improve submaximal exercise performance.

  3. Effect of moderate dietary restriction on visceral organ weight, hepatic oxygen consumption, and metabolic proteins associated with energy balance in mature pregnant beef cows.

    Science.gov (United States)

    Wood, K M; Awda, B J; Fitzsimmons, C; Miller, S P; McBride, B W; Swanson, K C

    2013-09-01

    Twenty-two nonlactating multiparous pregnant beef cows (639 ± 68 kg) were used to investigate the effect of dietary restriction on the abundance of selected proteins regulating cellular energy metabolism. Cows were fed at either 85% (n = 11; LOW) or 140% (n = 11; HIGH) of total NE requirements. The diet consisted of a haylage-based total mixed ration containing 20% wheat straw. Cows were slaughtered by block (predicted date of parturition), beginning 83 d after the initiation of dietary treatments and every week thereafter for 6 wk, such that each block was slaughtered at approximately 250 d of gestation. Tissue samples from liver, kidney, sternomandibularis muscle, ruminal papilli (ventral sac), pancreas, and small intestinal muscosa were collected at slaughter and snap frozen in liquid N2. Western blots were conducted to quantify abundance of proliferating cell nuclear antigen (PCNA), ATP synthase, ubiquitin, and Na/K+ ATPase for all tissues; PPARγ, PPARγ coactivator 1 α (PGC-1α), and 5´-adenosine monophosphate-activated protein kinase (AMPK) and the activated form phosphorylated-AMPK (pAMPK) for liver, muscle, and rumen; phosphoenolpyruvate carboxykinase (PEPCK) for liver and kidney; and uncoupling protein 2 (UCP2) for liver. Statistical analysis was conducted using Proc Mixed in SAS and included the fixed effects of dietary treatment, cow age, block, and the random effect of pen. Dietary treatments resulted in cows fed HIGH having greater (P ≤ 0.04) ADG and final BW than cows fed LOW. Abundance of ubiquitin in muscle was greater (P = 0.009) in cows fed LOW, and PCG-1 α in liver was greater (P = 0.03) in cows fed HIGH. Hepatic O2 consumption was greater in HIGH (P ≤ 0.04). Feed intake can influence the abundance of important metabolic proteins and suggest that protein degradation may increase in muscle from moderately nutrient restricted cows and that energy metabolism in liver increases in cows fed above NE requirements.

  4. High-intensity interval training and β-hydroxy-β-methylbutyric free acid improves aerobic power and metabolic thresholds

    Science.gov (United States)

    2014-01-01

    Background Previous research combining Calcium β-hydroxy-β-methylbutyrate (CaHMB) and running high-intensity interval training (HIIT) have shown positive effects on aerobic performance measures. The purpose of this study was to examine the effect of β-hydroxy-β-methylbutyric free acid (HMBFA) and cycle ergometry HIIT on maximal oxygen consumption (VO2peak), ventilatory threshold (VT), respiratory compensation point (RCP) and time to exhaustion (Tmax) in college-aged men and women. Methods Thirty-four healthy men and women (Age: 22.7 ± 3.1 yrs ; VO2peak: 39.3 ± 5.0 ml · kg-1 · min-1) volunteered to participate in this double-blind, placebo-controlled design study. All participants completed a series of tests prior to and following treatment. A peak oxygen consumption test was performed on a cycle ergometer to assess VO2peak, Tmax, VT, and RCP. Twenty-six participants were randomly assigned into either a placebo (PLA-HIIT) or 3 g per day of HMBFA (BetaTor™) (HMBFA-HIIT) group. Eight participants served as controls (CTL). Participants in the HIIT groups completed 12 HIIT (80-120% maximal workload) exercise sessions consisting of 5–6 bouts of a 2:1 minute cycling work to rest ratio protocol over a four-week period. Body composition was measured with dual energy x-ray absorptiometry (DEXA). Outcomes were assessed by ANCOVA with posttest means adjusted for pretest differences. Results The HMBFA-HIIT intervention showed significant (p HIIT group. Both PLA-HIIT and HMBFA-HIIT treatment groups demonstrated significant (p HIIT and HMBFA-HIIT groups. Conclusions Our findings support the use of HIIT in combination with HMBFA to improve aerobic fitness in college age men and women. These data suggest that the addition of HMBFA supplementation may result in greater changes in VO2peak and VT than HIIT alone. Study registration The study was registered on ClinicalTrials.gov (ID NCT01941368). PMID:24782684

  5. High-intensity interval training and β-hydroxy-β-methylbutyric free acid improves aerobic power and metabolic thresholds.

    Science.gov (United States)

    Robinson, Edward H; Stout, Jeffrey R; Miramonti, Amelia A; Fukuda, David H; Wang, Ran; Townsend, Jeremy R; Mangine, Gerald T; Fragala, Maren S; Hoffman, Jay R

    2014-01-01

    Previous research combining Calcium β-hydroxy-β-methylbutyrate (CaHMB) and running high-intensity interval training (HIIT) have shown positive effects on aerobic performance measures. The purpose of this study was to examine the effect of β-hydroxy-β-methylbutyric free acid (HMBFA) and cycle ergometry HIIT on maximal oxygen consumption (VO2peak), ventilatory threshold (VT), respiratory compensation point (RCP) and time to exhaustion (Tmax) in college-aged men and women. Thirty-four healthy men and women (Age: 22.7 ± 3.1 yrs ; VO2peak: 39.3 ± 5.0 ml · kg(-1) · min(-1)) volunteered to participate in this double-blind, placebo-controlled design study. All participants completed a series of tests prior to and following treatment. A peak oxygen consumption test was performed on a cycle ergometer to assess VO2peak, Tmax, VT, and RCP. Twenty-six participants were randomly assigned into either a placebo (PLA-HIIT) or 3 g per day of HMBFA (BetaTor™) (HMBFA-HIIT) group. Eight participants served as controls (CTL). Participants in the HIIT groups completed 12 HIIT (80-120% maximal workload) exercise sessions consisting of 5-6 bouts of a 2:1 minute cycling work to rest ratio protocol over a four-week period. Body composition was measured with dual energy x-ray absorptiometry (DEXA). Outcomes were assessed by ANCOVA with posttest means adjusted for pretest differences. The HMBFA-HIIT intervention showed significant (p body composition. An independent-samples t-test confirmed that there were no significant differences between the training volumes for the PLA-HIIT and HMBFA-HIIT groups. Our findings support the use of HIIT in combination with HMBFA to improve aerobic fitness in college age men and women. These data suggest that the addition of HMBFA supplementation may result in greater changes in VO2peak and VT than HIIT alone. The study was registered on ClinicalTrials.gov (ID NCT01941368).

  6. Cardiorespiratory Fitness Attenuates the Influence of Amyloid on Cognition.

    Science.gov (United States)

    Schultz, Stephanie A; Boots, Elizabeth A; Almeida, Rodrigo P; Oh, Jennifer M; Einerson, Jean; Korcarz, Claudia E; Edwards, Dorothy F; Koscik, Rebecca L; Dowling, Maritza N; Gallagher, Catherine L; Bendlin, Barbara B; Christian, Bradley T; Zetterberg, Henrik; Blennow, Kaj; Carlsson, Cynthia M; Asthana, Sanjay; Hermann, Bruce P; Sager, Mark A; Johnson, Sterling C; Stein, James H; Okonkwo, Ozioma C

    2015-11-01

    The aim of this study was to examine cross-sectionally whether higher cardiorespiratory fitness (CRF) might favorably modify amyloid-β (Aβ)-related decrements in cognition in a cohort of late-middle-aged adults at risk for Alzheimer's disease (AD). Sixty-nine enrollees in the Wisconsin Registry for Alzheimer's Prevention participated in this study. They completed a comprehensive neuropsychological exam, underwent 11C Pittsburgh Compound B (PiB)-PET imaging, and performed a graded treadmill exercise test to volitional exhaustion. Peak oxygen consumption (VO2peak) during the exercise test was used as the index of CRF. Forty-five participants also underwent lumbar puncture for collection of cerebrospinal fluid (CSF) samples, from which Aβ42 was immunoassayed. Covariate-adjusted regression analyses were used to test whether the association between Aβ and cognition was modified by CRF. There were significant VO2peak*PiB-PET interactions for Immediate Memory (p=.041) and Verbal Learning & Memory (p=.025). There were also significant VO2peak*CSF Aβ42 interactions for Immediate Memory (p<.001) and Verbal Learning & Memory (p<.001). Specifically, in the context of high Aβ burden, that is, increased PiB-PET binding or reduced CSF Aβ42, individuals with higher CRF exhibited significantly better cognition compared with individuals with lower CRF. In a late-middle-aged, at-risk cohort, higher CRF is associated with a diminution of Aβ-related effects on cognition. These findings suggest that exercise might play an important role in the prevention of AD.

  7. Cardiopulmonary exercise testing prior to myeloablative allo-SCT: a feasibility study.

    Science.gov (United States)

    Kelsey, C R; Scott, J M; Lane, A; Schwitzer, E; West, M J; Thomas, S; Herndon, J E; Michalski, M G; Horwitz, M E; Hennig, T; Jones, L W

    2014-10-01

    The feasibility of symptom-limited cardiopulmonary exercise testing (CPET) prior to allo-SCT was assessed in addition to the prognostic value of CPET-derived measures. CPET was performed prospectively on 21 patients with hematologic malignancies, with assessments of peak (for example, peak oxygen consumption, VO2peak) and submaximal (for example, ventilatory threshold (VT)) measures of cardiopulmonary function. No serious adverse events were observed during CPET procedures, with 95% of patients achieving criteria for a peak test. Mean VO2peak was 24.7±6.4 mL kg(-1 )min(-1) (range: 10.9-35.5), equivalent to 29%±17% below that of age-matched healthy controls. All patients proceeded with the conditioning regimen followed by allo-SCT. Median follow-up was 25 months. During this period, 11 (52.4%) patients died (n=6, relapsed disease; n=5, non-relapse mortality (NRM)); 9 patients (43%) developed pulmonary toxicity. In univariate analyses, both peak and submaximal markers of cardiopulmonary function were predictors of OS, pulmonary toxicity and NRM. For OS, the HR for VO2peak and VT were 0.89 (95% CI, 0.8-0.99, P=0.04) and 0.84 (95% CI, 0.71-0.98, P=0.03), respectively. In conclusion, CPET is safe and feasible prior to allo-SCT. Patients have marked impairments in cardiopulmonary function prior to allo-SCT. CPET-derived metrics may complement conventional measures to improve risk stratification.

  8. Mitochondrial Respiration and Oxygen Tension.

    Science.gov (United States)

    Shaw, Daniel S; Meitha, Karlia; Considine, Michael J; Foyer, Christine H

    2017-01-01

    Measurements of respiration and oxygen tension in plant organs allow a precise understanding of mitochondrial capacity and function within the context of cellular oxygen metabolism. Here we describe methods that can be routinely used for the isolation of intact mitochondria, and the determination of respiratory electron transport, together with techniques for in vivo determination of oxygen tension and measurement of respiration by both CO 2 production and O 2 consumption that enables calculation of the respiratory quotient [CO 2 ]/[O 2 ].

  9. Sustainable Consumption

    DEFF Research Database (Denmark)

    Røpke, Inge

    2015-01-01

    The intention of this chapter is to explore the role of consumption and consumers in relation to sustainability transition processes and wider systemic transformations. In contrast to the individualistic focus in much research on sustainable consumption, the embeddedness of consumption activities...... in wider social, economic and technological frameworks is emphasised. In particular, the chapter is inspired by practice theory and transition theory. First, various trends in consumption are outlined to highlight some of the challenges for sustainability transitions. Then, it is discussed how consumption...... patterns are shaped over time and what should be considered in sustainability strategies. While discussions on consumption often take their point of departure in the perspective of the individual and then zoom to the wider context, the present approach is the opposite. The outline starts with the basic...

  10. Effect of Caloric Restriction or Aerobic Exercise Training on Peak Oxygen Consumption and Quality of Life in Obese Older Patients with Heart Failure and Preserved Ejection Fraction A Randomized, Controlled Trial

    Science.gov (United States)

    Kitzman, Dalane W.; Brubaker, Peter; Morgan, Timothy; Haykowsky, Mark; Hundley, Gregory; Kraus, William E.; Eggebeen, Joel; Nicklas, Barbara J.

    2016-01-01

    Importance More than 80% of patients with heart failure with preserved ejection fraction (HFPEF), the most common form of HF among older persons, are overweight/obese. Exercise intolerance is the primary symptom of chronic HFPEF and a major determinant of reduced quality-of-life (QOL). Objective To determine whether caloric restriction (Diet), or aerobic exercise training (Exercise), improves exercise capacity and QOL in obese older HFPEF patients. Design Randomized, attention-controlled, 2x2 factorial trial conducted from February 2009 November 2014. Setting Urban academic medical center. Participants 100 older (67±5 years) obese (BMI=39.3±5.6kg/m2) women (n=81) and men (n=19) with chronic, stable HFPEF enrolled from 577 patients initially screened (366 excluded by inclusion / exclusion criteria, 31 for other reasons, 80 declined participation). Twenty-six participants were randomized to Exercise alone, 24 to Diet alone, 25 to Diet+Exercise, and 25 to Control; 92 completed the trial. Interventions 20 weeks of Diet and/or Exercise; Attention Control consisted of telephone calls every 2 weeks. Main Outcomes and Measures Exercise capacity measured as peak oxygen consumption (VO2, ml/kg/min; primary outcome) and QOL measured by the Minnesota Living with HF Questionnaire (MLHF) total score (co-primary outcome; score range: 0–105, higher scores indicate worse HF-related QOL). Results By main effects analysis, peak VO2 was increased significantly by both interventions: Exercise main effect 1.2 ml/kg/min (95%CI: 0.7,1.7; pDiet main effect 1.3 ml/kg/min (95%CI: 0.8,1.8; pExercise+Diet was additive (complementary) for peak VO2 (joint effect 2.5 ml/kg/min). The change in MLHF total score was non-significant with Exercise (main effect −1 unit; 95%CI: −8,5; p=0.70) and with Diet (main effect −6 units; 95%CI: −12,1; p=0.078). The change in peak VO2 was positively correlated with the change in percent lean body mass (r=0.32; p=0.003) and the change in thigh muscle

  11. THE CONTRIBUTION OF 'RESTING' BODY MUSCLES TO THE SLOW COMPONENT OF PULMONARY OXYGEN UPTAKE DURING HIGH-INTENSITY CYCLING

    Directory of Open Access Journals (Sweden)

    Susan A. Ward

    2012-12-01

    Full Text Available Oxygen uptake (VO2 kinetics during moderate constant- workrate (WR exercise (>lactate-threshold (ӨL are well described as exponential. AboveӨL, these kinetics are more complex, consequent to the development of a delayed slow component (VO2sc, whose aetiology remains controversial. To assess the extent of the contribution to the VO2sc from arm muscles involved in postural stability during cycling, six healthy subjects completed an incremental cycle-ergometer test to the tolerable limit for estimation of ӨL and determination of peak VO2. They then completed two constant-WR tests at 90% of ӨL and two at 80% of ∆ (difference between ӨL and VO2peak. Gas exchange variables were derived breath-by-breath. Local oxygenation profiles of the vastus lateralis and biceps brachii muscles were assessed by near-infrared spectroscopy, with maximal voluntary contractions (MVC of the relevant muscles being performed post-exercise to provide a frame of reference for normalising the exercise-related oxygenation responses across subjects. Above supra-ӨL, VO2 rose in an exponential-like fashion ("phase 2, with a delayed VO2sc subsequently developing. This was accompanied by an increase in [reduced haemoglobin] relative to baseline (∆[Hb], which attained 79 ± 13 % (mean, SD of MVC maximum in vastus lateralis at end-exercise and 52 ± 27 % in biceps brachii. Biceps brachii ∆[Hb] was significantly correlated with VO2 throughout the slow phase. In contrast, for sub- L exercise, VO2 rose exponentially to reach a steady state with a more modest increase in vastus lateralis ∆[Hb] (30 ± 11 %; biceps brachii ∆[Hb] was minimally affected (8 ± 2 %. That the intramuscular O2 desaturation profile in biceps brachii was proportional to that for VO2sc during supra-ӨL cycle ergometry is consistent with additional stabilizing arm work contributing to the VO2sc

  12. Oxygen toxicity

    Directory of Open Access Journals (Sweden)

    C. A. van der Westhuizen

    1990-07-01

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

  13. Optic nerve oxygenation

    DEFF Research Database (Denmark)

    Stefánsson, Einar; Pedersen, Daniella Bach; Jensen, Peter Koch

    2005-01-01

    The oxygen tension of the optic nerve is regulated by the intraocular pressure and systemic blood pressure, the resistance in the blood vessels and oxygen consumption of the tissue. The oxygen tension is autoregulated and moderate changes in intraocular pressure or blood pressure do not affect...... the optic nerve oxygen tension. If the intraocular pressure is increased above 40 mmHg or the ocular perfusion pressure decreased below 50 mmHg the autoregulation is overwhelmed and the optic nerve becomes hypoxic. A disturbance in oxidative metabolism in the cytochromes of the optic nerve can be seen...... at similar levels of perfusion pressure. The levels of perfusion pressure that lead to optic nerve hypoxia in the laboratory correspond remarkably well to the levels that increase the risk of glaucomatous optic nerve atrophy in human glaucoma patients. The risk for progressive optic nerve atrophy in human...

  14. A theoretical model for oxygen transport in skeletal muscle under conditions of high oxygen demand.

    Science.gov (United States)

    McGuire, B J; Secomb, T W

    2001-11-01

    Oxygen transport from capillaries to exercising skeletal muscle is studied by use of a Krogh-type cylinder model. The goal is to predict oxygen consumption under conditions of high demand, on the basis of a consideration of transport processes occurring at the microvascular level. Effects of the decline in oxygen content of blood flowing along capillaries, intravascular resistance to oxygen diffusion, and myoglobin-facilitated diffusion are included. Parameter values are based on human skeletal muscle. The dependence of oxygen consumption on oxygen demand, perfusion, and capillary density are examined. When demand is moderate, the tissue is well oxygenated and consumption is slightly less than demand. When demand is high, capillary oxygen content declines rapidly with axial distance and radial oxygen transport is limited by diffusion resistance within the capillary and the tissue. Under these conditions, much of the tissue is hypoxic, consumption is substantially less than demand, and consumption is strongly dependent on capillary density. Predicted consumption rates are comparable with experimentally observed maximal rates of oxygen consumption.

  15. Oxygen requirement of separated hybrid catfish eggs

    Science.gov (United States)

    Channel catfish egg masses require hatchery water with over 7.8 ppm dissolved oxygen at 80° F (95% air saturation) to maintain maximum oxygen consumption as they near hatching. This concentration is called the critical oxygen requirement by scientists but for the purpose of this article we will call...

  16. Assembling consumption

    DEFF Research Database (Denmark)

    Assembling Consumption marks a definitive step in the institutionalisation of qualitative business research. By gathering leading scholars and educators who study markets, marketing and consumption through the lenses of philosophy, sociology and anthropology, this book clarifies and applies...... the investigative tools offered by assemblage theory, actor-network theory and non-representational theory. Clear theoretical explanation and methodological innovation, alongside empirical applications of these emerging frameworks will offer readers new and refreshing perspectives on consumer culture and market...... societies. This is an essential reading for both seasoned scholars and advanced students of markets, economies and social forms of consumption....

  17. The acute effects of interval- vs. continuous-walking exercise on glycemic control in subjects with type 2 diabetes

    DEFF Research Database (Denmark)

    Karstoft, Kristian; Christensen, Camilla S; Pedersen, Bente K

    2014-01-01

    Context: Glycemic control improves with physical activity, but the optimal exercise mode is unknown. Objective: To determine whether interval-based exercise improves postprandial glucose tolerance and free-living glycemia more than oxygen-consumption and time-duration matched continuous exercise....... Design: Cross-over, controlled with trials performed in randomized order. Setting: Hospitalized and ambulatory care. Patients: Diagnosed with type 2 diabetes (T2DM; n=10, no withdrawels). Interventions: Subjects performed three 1-hour interventions: 1) interval-walking (IW; repeated cycles of 3 minutes...... of slow and fast walking); 2) continuous-walking (CW); 3) Control (CON). Oxygen consumption (VO2) was measured continuously to match mean VO2 between exercise sessions (∼75% VO2peak). Main Outcome Measures: A mixed meal tolerance test (MMTT; 450 kcal, 55% carbohydrate) with stable glucose isotopic tracers...

  18. Oxygen Therapy

    Science.gov (United States)

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

  19. Endurance Exercise in Hypoxia, Hyperoxia and Normoxia: Mitochondrial and Global Adaptations.

    Science.gov (United States)

    Przyklenk, Axel; Gutmann, Boris; Schiffer, Thorsten; Hollmann, Wildor; Strueder, Heiko K; Bloch, Wilhelm; Mierau, Andreas; Gehlert, Sebastian

    2017-07-01

    We hypothesized short-term endurance exercise (EN) in hypoxia (HY) to exert decreased mitochondrial adaptation, peak oxygen consumption (VO 2peak ) and peak power output (PPO) compared to EN in normoxia (NOR) and hyperoxia (PER). 11 male subjects performed repeated unipedal cycling EN in HY, PER, and NOR over 4 weeks in a cross-over design. VO 2peak , PPO, rate of perceived exertion (RPE) and blood lactate (Bla) were determined pre- and post-intervention to assess physiological demands and adaptation. Skeletal muscle biopsies were collected to determine molecular mitochondrial signaling and adaptation. Despite reduced exercise intensity (P0.05). Electron transport chain complexes tended to increase in all groups with the highest increase in HY (n.s.). EN-induced mitochondrial adaptability and exercise capacity neither decreased significantly in HY nor increased in PER compared to NOR. Despite decreased exercise intensity, short term EN under HY may not necessarily impair mitochondrial adaptation and exercise capacity while PER does not augment adaptation. HY might strengthen adaptive responses under circumstances when absolute training intensity has to be reduced. © Georg Thieme Verlag KG Stuttgart · New York.

  20. Glutamate availability is important in intramuscular amino acid metabolism and TCA cycle intermediates but does not affect peak oxidative metabolism.

    Science.gov (United States)

    Mourtzakis, M; Graham, T E; González-Alonso, J; Saltin, B

    2008-08-01

    Muscle glutamate is central to reactions producing 2-oxoglutarate, a tricarboxylic acid (TCA) cycle intermediate that essentially expands the TCA cycle intermediate pool during exercise. Paradoxically, muscle glutamate drops approximately 40-80% with the onset of exercise and 2-oxoglutarate declines in early exercise. To investigate the physiological relationship between glutamate, oxidative metabolism, and TCA cycle intermediates (i.e., fumarate, malate, 2-oxoglutarate), healthy subjects trained (T) the quadriceps of one thigh on the single-legged knee extensor ergometer (1 h/day at 70% maximum workload for 5 days/wk), while their contralateral quadriceps remained untrained (UT). After 5 wk of training, peak oxygen consumption (VO2peak) in the T thigh was greater than that in the UT thigh (PTCA cycle intermediates. In the UT thigh, peak exercise (vs. rest) induced an increase in fumarate (0.33+/-0.07 vs. 0.02+/-0.01 mmol/kg dry wt (dw), PTCA cycle, glutamate and TCA cycle intermediates do not directly affect VO2peak in either trained or untrained muscle.

  1. Obstructive Sleep Apnea Syndrome, Objectively Measured Physical Activity and Exercise Training Interventions: A Systematic Review and Meta-Analysis

    Directory of Open Access Journals (Sweden)

    Monique Mendelson

    2018-02-01

    Full Text Available A systematic review of English and French articles using Pubmed/Medline and Embase included studies assessing objective physical activity levels of obstructive sleep apnea (OSA patients and exploring the effects of exercise training on OSA severity, body mass index (BMI, sleepiness, and cardiorespiratory fitness [peak oxygen consumption (VO2peak]. Two independent reviewers analyzed the studies, extracted the data, and assessed the quality of evidence. For objective physical activity levels, eight studies were included. The mean number of steps per day across studies was 5,388 (95% CI: 3,831–6,945; p < 0.001, which was by far lower than the recommended threshold of 10,000 steps per day. For exercise training, six randomized trials were included. There was a significant decrease in apnea–hypopnea-index following exercise training (mean decrease of 8.9 events/h; 95% CI: −13.4 to −4.3; p < 0.01, which was accompanied by a reduction in subjective sleepiness, an increase in VO2peak and no change in BMI. OSA patients present low levels of physical activity and exercise training is associated with improved outcomes. Future interventions (including exercise training focusing on increasing physical activity levels may have important clinical impacts on both OSA severity and the burden of associated co-morbidities. Objective measurement of physical activity in routine OSA management and well-designed clinical trials are recommended.Registration # CRD42017057319 (Prospero.

  2. Obstructive Sleep Apnea Syndrome, Objectively Measured Physical Activity and Exercise Training Interventions: A Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Mendelson, Monique; Bailly, Sébastien; Marillier, Mathieu; Flore, Patrice; Borel, Jean Christian; Vivodtzev, Isabelle; Doutreleau, Stéphane; Verges, Samuel; Tamisier, Renaud; Pépin, Jean-Louis

    2018-01-01

    A systematic review of English and French articles using Pubmed/Medline and Embase included studies assessing objective physical activity levels of obstructive sleep apnea (OSA) patients and exploring the effects of exercise training on OSA severity, body mass index (BMI), sleepiness, and cardiorespiratory fitness [peak oxygen consumption (VO2peak)]. Two independent reviewers analyzed the studies, extracted the data, and assessed the quality of evidence. For objective physical activity levels, eight studies were included. The mean number of steps per day across studies was 5,388 (95% CI: 3,831-6,945; p  < 0.001), which was by far lower than the recommended threshold of 10,000 steps per day. For exercise training, six randomized trials were included. There was a significant decrease in apnea-hypopnea-index following exercise training (mean decrease of 8.9 events/h; 95% CI: -13.4 to -4.3; p  < 0.01), which was accompanied by a reduction in subjective sleepiness, an increase in VO2peak and no change in BMI. OSA patients present low levels of physical activity and exercise training is associated with improved outcomes. Future interventions (including exercise training) focusing on increasing physical activity levels may have important clinical impacts on both OSA severity and the burden of associated co-morbidities. Objective measurement of physical activity in routine OSA management and well-designed clinical trials are recommended. Registration # CRD42017057319 (Prospero).

  3. Effects of manipulating the duration and intensity of aerobic training sessions on the physical performance of rats.

    Science.gov (United States)

    Teixeira-Coelho, Francisco; Fonseca, Cletiana Gonçalves; Barbosa, Nicolas Henrique Santos; Vaz, Filipe Ferreira; Cordeiro, Letícia Maria de Souza; Coimbra, Cândido Celso; Pires, Washington; Soares, Danusa Dias; Wanner, Samuel Penna

    2017-01-01

    This study investigated the effects of manipulating the load components of aerobic training sessions on the physical performance of rats. To achieve this purpose, adult male Wistar rats were divided into four groups: an untrained control (CON) group and training groups with a predominant overload in intensity (INT) or duration (DUR) or alternating and similar overloads in intensity and duration (ID). Prior to, during, and after 8 weeks of the control or training protocols, the performance of the rats (evaluated by their workload) was determined during fatiguing, incremental-speed treadmill running. Two additional incremental running tests were performed prior to and at the end of the protocols to measure the peak rate of oxygen consumption (VO2peak). As expected, the rats in the trained groups exhibited increased performance, whereas the untrained rats showed stable performance throughout the 8 weeks. Notably, the performance gain exhibited by the DUR rats reached a plateau after the 4th week. This plateau was not present in the INT or ID rats, which exhibited increased performance at the end of training protocol compared with the DUR rats. None of the training protocols changed the VO2peak values; however, these values were attained at faster speeds, which indicated increased running economy. In conclusion, our findings demonstrate that the training protocols improved the physical performance of rats, likely resulting from enhanced running economy. Furthermore, compared with overload in duration, overload in the intensity of training sessions was more effective at inducing performance improvements across the 8 weeks of the study.

  4. INFLUENCE OF PHYSICAL TRAINING ON CARDIORESPIRATORY ENDURANCE IN PREADOLESCENT AGE

    Directory of Open Access Journals (Sweden)

    Marjan Marinkovic

    2009-01-01

    Full Text Available Cardiorespiratory or aerobic endurance is the ability of the whole body to sustain physical activity for an extended period of time, involving relatively large groups of muscles. The attitudes on the possible impact of training on cardiorespiratory endurance in preadolescents are contradictory. Our study enrolled 195 boys aged 11 to 12 years. Experimental group (n=92 consisted of the children who had been involved with planned and programmed water polo training for at least two years. Control group (n=103 consisted of schoolchildren who only had had regular physical education in schools. Our investigation protocol included standardized anthropometric measurements and tests, performed respecting the appropriate protocols. Statistical analysis of the results demonstrated that there were no significant differences in age and relative values of oxygen consumption (VO2peak. Body height and mass, as well as the skinfold thickness, were significantly higher in experimental group subjects. The values of absolute VO2peak, FVC and FEV1.0 were also significantly higher in the examinees involved with water polo training. These findings stress the importance of a systematic training process even in this early period of growth and development in order for the trainees to acquire important functional advantages. We believe that a properly planned and programmed physical training can significantly contribute to the development of cardiorespiratory endurance even as early as preadolescent age.

  5. Oxygen Therapy

    Directory of Open Access Journals (Sweden)

    Bonnie Solmes

    2000-01-01

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

  6. Collaborative Consumption

    DEFF Research Database (Denmark)

    Gjerdrum Pedersen, Esben Rahbek; Netter, Sarah

    2015-01-01

    Purpose – The purpose of this paper is to explore barriers and opportunities for business models based on the ideas of collaborative consumption within the fashion industry. Design/methodology/approach – The analysis is based on a multiple-case study of Scandinavian fashion libraries – a new...... to the new phenomenon of fashion libraries and does not cover other types of collaborative consumption within the fashion industry (Swap-parties, etc.). Originality/value – The paper is one of the first attempts to examine new business models of collaborative consumption in general and the fashion library...... concept in particular. The study contributes to the discussions of whether and how fashion sharing and collaboration holds promise as a viable business model and as a means to promote sustainability....

  7. Collaborative Consumption

    DEFF Research Database (Denmark)

    Gjerdrum Pedersen, Esben Rahbek; Netter, Sarah

    Purpose: The purpose of this paper is to explore barriers and opportunities for business models based on the ideas of collaborative consumption within the fashion industry. Design/methodology/approach: The analysis is based on a multiple-­‐‑case study of Scandinavian fashion libraries – a new...... to the new phenomenon of fashion libraries and does not cover other types of collaborative consumption within the fashion industry (Swap-­‐‑parties, etc.). Originality/value: The paper is one of the first attempts to examine new business models of collaborative consumption in general and the fashion library...... concept in particular. The study contributes to the discussions of whether and how fashion sharing and collaboration holds promise as a viable business model and as a means to promote sustainability....

  8. Positioning consumption

    DEFF Research Database (Denmark)

    Halkier, Bente; Keller, Margit

    2014-01-01

    positionings emerges based on empirical examples of research in parent–children consumption. Positionings are flexible discursive fixations of the relationship between the performances of the practitioner, other practitioners, media discourse and consumption activities. The basic positioning types...... are the practice maintenance and the practice change position, with different sorts of adapting in between. Media discourse can become a resource for a resistant position against social control or for an appropriating position in favour of space for action. Regardless of the current relation to a particular media......This article analyses the ways in which media discourses become a part of contested consumption activities. We apply a positioning perspective with practice theory to focus on how practitioners relate to media discourse as a symbolic resource in their everyday practices. A typology of performance...

  9. Lean consumption.

    Science.gov (United States)

    Womack, James P; Jones, Daniel T

    2005-03-01

    During the past 20 years, the real price of most consumer goods has fallen worldwide, the variety of goods and the range of sales channels offering them have continued to grow, and product quality has steadily improved. So why is consumption often so frustrating? It doesn't have to be--and shouldn't be--the authors say. They argue that it's time to apply lean thinking to the processes of consumption--to give consumers the full value they want from goods and services with the greatest efficiency and the least pain. Companies may think they save time and money by off-loading work to the consumer but, in fact, the opposite is true. By streamlining their systems for providing goods and services, and by making it easier for customers to buy and use those products and services, a growing number of companies are actually lowering costs while saving everyone time. In the process, these businesses are learning more about their customers, strengthening consumer loyalty, and attracting new customers who are defecting from less user-friendly competitors. The challenge lies with the retailers, service providers, manufacturers, and suppliers that are not used to looking at total cost from the standpoint of the consumer and even less accustomed to working with customers to optimize the consumption process. Lean consumption requires a fundamental shift in the way companies think about the relationship between provision and consumption, and the role their customers play in these processes. It also requires consumers to change the nature of their relationships with the companies they patronize. Lean production has clearly triumphed over similar obstacles in recent years to become the dominant global manufacturing model. Lean consumption, its logical companion, can't be far behind.

  10. The oxygen effect and cellular adaptation

    International Nuclear Information System (INIS)

    Meshcherikova, V.V.; Vajnson, A.A.; Yarmonenko, S.P.

    1979-01-01

    The radiomodifying effect of oxygen was shown to depend on the level of cellular oxygenation prior to irradiation. Acute hypoxia created at the time of irradiation protects previously normally oxygenated cells with DMF approximately 1.4 times larger than that of cells cultured for 24 hours under conditions of mild hypoxia. It is suggested that a decrease in the radioprotective effect of acute hypoxia on chronically hypoxic cells is correlated with an appreciable decrease in the rate of oxygen consumption by these cells, due to which the oxygen concentration near the intracellular targets in chronically hypoxic cells may be higher than in normal cells under conditions of poor oxygenation

  11. Intraportal islet oxygenation.

    Science.gov (United States)

    Suszynski, Thomas M; Avgoustiniatos, Efstathios S; Papas, Klearchos K

    2014-05-01

    Islet transplantation (IT) is a promising therapy for the treatment of diabetes. The large number of islets required to achieve insulin independence limit its cost-effectiveness and the number of patients who can be treated. It is believed that >50% of islets are lost in the immediate post-IT period. Poor oxygenation in the early post-IT period is recognized as a possible reason for islet loss and dysfunction but has not been extensively studied. Several key variables affect oxygenation in this setting, including (1) local oxygen partial pressure (pO(2)), (2) islet oxygen consumption, (3) islet size (diameter, D), and (4) presence or absence of thrombosis on the islet surface. We discuss implications of oxygen-limiting conditions on intraportal islet viability and function. Of the 4 key variables, the islet size appears to be the most important determinant of the anoxic and nonfunctional islet volume fractions. Similarly, the effect of thrombus formation on the islet surface may be substantial. At the University of Minnesota, average size distribution data from clinical alloislet preparations (n = 10) indicate that >150-µm D islets account for only ~30% of the total islet number, but >85% of the total islet volume. This suggests that improved oxygen supply to the islets may have a profound impact on islet survivability and function since most of the β-cell volume is within large islets which are most susceptible to oxygen-limiting conditions. The assumption that the liver is a suitable islet transplant site from the standpoint of oxygenation should be reconsidered. © 2014 Diabetes Technology Society.

  12. Unsustainable Consumption

    DEFF Research Database (Denmark)

    Thøgersen, John

    2014-01-01

    Our dominant way of living is not sustainable and our activities as private individuals and households directly and indirectly account for a large and increasing share of total environmental impacts. These impacts are related to the structure as well as the level of consumption. In this article, ...

  13. Consumption bomb.

    Science.gov (United States)

    Harrison, P

    1999-01-01

    This article focuses on the issue of consumption in relation to the growing world population. Over the past 25 years, world population increased by 53%, while world consumption per person increased by only 39%. If consumption continues to grow at 1.4%, the world consumption per person will rise by 100% over the next 50 years with the population increasing by only half that amount. The burden of reducing the environmental impact brought about by this increase lies on technology. Technology needs to deliver major changes in improving resource productivity, and decreasing the amount of waste created. Productivity such as global food production has kept up with demand. Malnutrition persists due to poverty, and not because of the inability of the world to produce enough food. However, the prospects are much worse for resources that are not traded on markets or subject to sustainable management such as groundwater, state forests, ocean fish, and communal waste sinks like rivers, lakes, and the global atmosphere. These resources are not under the direct control of people affected by shortage. People who want to change the way these resources are used or managed have to pass through the legal or political system. Usually, political responses are slow and there has to be a very widespread environmental damage before action is taken.

  14. Transdisciplinary Consumption

    Directory of Open Access Journals (Sweden)

    Sue L.T. McGregor

    2013-06-01

    Full Text Available For the past 100 years, research about consumption has stemmed from two main disciplines: (a consumer studies/consumer sciences (including consumer policy and education (a spin off from home economics and (b consumer behaviour research (a spin off from marketing. This paper focuses on these two disciplines because the results of their respective research are used to shape consumer policy and consumer protection legislation and regulations, marketplace competition policy and regulations, consumer product and service information, media coverage of consumer issues, consumer education curricula and pedagogy, and insights into an evolving consumer culture. This paper asks consumer studies/sciences and consumer behaviour scholars to embrace the transdisciplinary methodology in addition to the traditional empirical, interpretive and critical methodologies. It provides an overview of the four axioms of transdisciplinary methodology with examples to illustrate how consumer-related research would change to address the complex reality of 21st century consumption.

  15. Collaborative Consumption

    OpenAIRE

    Rahbek Gjerdrum Pedersen, Esben; Netter, Sarah

    2013-01-01

    Purpose: The purpose of this paper is to explore barriers and opportunities for business models based on the ideas of collaborative consumption within the fashion industry. Design/methodology/approach: The analysis is based on a multiple-­‐‑case study of Scandinavian fashion libraries – a new, clothes-­‐‑sharing concept that has emerged as a fashion niche within the last decade. Findings: It is concluded that fashion libraries offers interesting perspectives, e.g. by allow...

  16. Flexible Consumption

    DEFF Research Database (Denmark)

    Holm Jacobsen, Peter; Pallesen, Trine

    This report presents the first findings from our qualitative study of consumer behaviour vis-à-vis flexible consumption. The main of objective of this report is to present our first round of data from Bornholm, and to assist the design of products/services designed in WP6. In the report, we adopt...... the perspective of the consumer: what does living in a demand response setup look like to participants – and what kinds of behaviour and interest motivate – and emerge from – their participation in EcoGrid 2.0....

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

    International Nuclear Information System (INIS)

    Ehpshtejn, I.M.

    1978-01-01

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

  18. Consumption governance toward more sustainable consumption

    NARCIS (Netherlands)

    Wahlen, S.; Dubuisson-Quellier, Sophie

    2018-01-01

    This article deliberates on strategies of consumption governance toward more sustainable consumption. We discuss theoretical concepts stemming from various social science perspectives to (1) promote more sustainable consumption, (2) compare strategies stemming from individualist understanding of

  19. Low Cardiorespiratory Fitness is Partially Linked to Ventilatory Factors in Obese Adolescents.

    Science.gov (United States)

    Mendelson, Monique; Michallet, Anne-Sophie; Tonini, Julia; Favre-Juvin, Anne; Guinot, Michel; Wuyam, Bernard; Flore, Patrice

    2016-02-01

    To examine the role of ventilatory constraint on cardiorespiratory fitness in obese adolescents. Thirty obese adolescents performed a maximal incremental cycling exercise and were divided into 2 groups based on maximal oxygen uptake (VO2peak): those presenting low (L; n = 15; VO2peak: 72.9 ± 8.6% predicted) or normal (N; n = 15; VO2peak: 113.6 ± 19.2% predicted) cardiorespiratory fitness. Both were compared with a group of healthy controls (C; n = 20; VO2peak: 103.1 ± 11.2% predicted). Ventilatory responses were explored using the flow volume loop method. Cardiorespiratory fitness (VO2peak, in % predicted) was lower in L compared with C and N and was moderately associated with the percent predicted forced vital capacity (FVC) (r = .52; p < .05) in L. At peak exercise, end inspiratory point was lower in L compared with N and C (77.4 ± 8.1, 86.4 ± 7.7, and 89.9 ± 7.6% FVC in L, N, and C, respectively; p < .05), suggesting an increased risk of ventilatory constraint in L, although at peak exercise this difference could be attributed to the lower maximal ventilation in L. Forced vital capacity and ventilatory strategy to incremental exercise slightly differed between N and L. These results suggest a modest participation of ventilatory factors to exercise intolerance.

  20. Effects of high aerobic intensity training in patients with schizophrenia: a controlled trial.

    Science.gov (United States)

    Heggelund, Jørn; Nilsberg, Geir E; Hoff, Jan; Morken, Gunnar; Helgerud, Jan

    2011-09-01

    Patients with schizophrenia have a high risk of cardiovascular disease (CVD). High aerobic intensity training (HIT) improve peak oxygen uptake (VO(2peak)), net mechanical efficiency of walking and risk factors for CVD but has not been investigated in patients with schizophrenia. To investigate effects from HIT on VO(2peak), net mechanical efficiency of walking and risk factors for CVD in patients with schizophrenia. 25 inpatients (F20-29, ICD-10) were allocated to either HIT or playing computer games (CG), 3 days per week for 8 weeks. HIT consisted of 4 × 4-min intervals with 3-min break periods, at 85-95% and 70% of peak heart rate, respectively. 12 and seven patients completed HIT and CG, respectively. The baseline VO(2peak) in both groups combined (n = 19) was 36.8 ± 8.2 ml/kg/min and 3.12 ± 0.55 l/min. The HIT group improved VO(2peak) by 12% from 3.17 ± 0.59 to 3.56 ± 0.68 l/min (P Negative Syndrome Scale (PANSS) and the Calgary Depression Scale for Schizophrenia (CDSS), did not improve in either group. VO(2peak) and net mechanical efficiency of walking improved significantly by 8 weeks of HIT. HIT should be included in rehabilitation in order to improve physical capacity and contribute risk reduction of CVD.

  1. Sustainable consumption

    DEFF Research Database (Denmark)

    Prothero, Andrea; Dobscha, Susan; Freund, Jim

    2011-01-01

    This essay explores sustainable consumption and considers possible roles for marketing and consumer researchers and public policy makers in addressing the many sustainability challenges that pervade our planet. Future research approaches to this interdisciplinary topic need to be comprehensive...... and systematic and will benefit from a variety of different perspectives. There are a number of opportunities for future research, and three areas are explored in detail. First, the essay considers the inconsistency between the attitudes and behaviors of consumers with respect to sustainability; next, the agenda...... is broadened to explore the role of individual citizens in society; and finally, a macro institutional approach to fostering sustainability is explored. Each of these areas is examined in detail and possible research avenues and public policy initiatives are considered within each of these separate...

  2. Time course for the recovery of physical performance, blood hemoglobin, and ferritin content after blood donation

    DEFF Research Database (Denmark)

    Ziegler, Andreas K; Grand, Johannes; Stangerup, Ida

    2015-01-01

    BACKGROUND: It is widely accepted that blood donation negatively affects endurance performance, but data on physical recovery after a standard blood donation are scarce. This study aimed to elucidate the temporary impact of blood donation on endurance performance, measured as peak oxygen uptake (VO......2peak ) and time trial (TT) performance. STUDY DESIGN AND METHODS: VO2peak , TT performance, blood, iron, and anthropometric variables were determined before (baseline) and 3, 7, 14, and 28 days after blood donation in 19 healthy men. RESULTS: VO2peak was reduced by 6.5% from 49.7 ± 2 m......L/kg/min at baseline to 46.3 ± 2 mL/kg/min on Day 3 (p donation. Blood hemoglobin (Hb) concentration declined 7.9% from 9.3 ± 0.11 mmol...

  3. Glutamate availability is important in intramuscular amino acid metabolism and TCA cycle intermediates but does not affect peak oxidative metabolism

    DEFF Research Database (Denmark)

    Mourtzakis, M.; Graham, T.E.; Gonzalez-Alonso, J.

    2008-01-01

    Muscle glutamate is central to reactions producing 2-oxoglutarate, a tricarboxylic acid (TCA) cycle intermediate that essentially expands the TCA cycle intermediate pool during exercise. Paradoxically, muscle glutamate drops approximately 40-80% with the onset of exercise and 2-oxoglutarate...... declines in early exercise. To investigate the physiological relationship between glutamate, oxidative metabolism, and TCA cycle intermediates (i.e., fumarate, malate, 2-oxoglutarate), healthy subjects trained (T) the quadriceps of one thigh on the single-legged knee extensor ergometer (1 h/day at 70......% maximum workload for 5 days/wk), while their contralateral quadriceps remained untrained (UT). After 5 wk of training, peak oxygen consumption (VO2peak) in the T thigh was greater than that in the UT thigh (Pglutamate infusion. Peak...

  4. Oxygen safety

    Science.gov (United States)

    ... sure you have working smoke detectors and a working fire extinguisher in your home. If you move around the house with your oxygen, you may need more than one fire extinguisher in different locations. Smoking can be very dangerous. No one should smoke ...

  5. Oxygen therapy - infants

    Science.gov (United States)

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

  6. Interactions between oxygen permeation and homogeneous-phase fuel conversion on the sweep side of an ion transport membrane

    KAUST Repository

    Hong, Jongsup; Kirchen, Patrick; Ghoniem, Ahmed F.

    2013-01-01

    concentration enhances oxygen permeation substantially. This is accomplished through promoting oxidation reactions (oxygen consumption) and the transport of the products and reaction heat towards the membrane, which lowers the oxygen concentration and increases

  7. Aquatic respiration rate measurements at low oxygen concentrations.

    Directory of Open Access Journals (Sweden)

    Moritz Holtappels

    Full Text Available 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.

  8. Brazilian Twin Registry: A Bright Future for Twin Studies/Twin Research: Twin Study of Alcohol Consumption and Mortality; Oxygen Uptake in Adolescent Twins/In the News: Superfecundated Twins In Vietnam; Adolescent Twin Relations; Twin and Triplet Co-Workers; A Special Twin Ultrasound; Monozygotic Twins With Different Skin Color; Identical Twin Returns from Space.

    Science.gov (United States)

    Segal, Nancy L

    2016-06-01

    The establishment of the Brazilian Twin Registry for the study of genetic, social, and cultural influences on behavior is one of eleven newly funded projects in the Department of Psychology at the University of São Paulo. These 11 interrelated projects form the core of the university's Center for Applied Research on Well-Being and Human Behavior. An overview of the planned twin research and activities to date is presented. Next, two recent twin studies are reviewed, one on the relationship between alcohol consumption and mortality, and the other on factors affecting maximal oxygen uptake. Twins cited in the media include the first identified superfecundated twins in Vietnam, adolescent twin relations, twins and triplets who work together, monozygotic twins with different skin tones and a co-twin control study that addresses the effects of space travel.

  9. THE EFFECT OF LIGHT COLOUR ON THE DIEL RHYTHM OF OXYGEN CONSUMPTION RATE IN JUVENILE CHINESE SHRIMP, FENNEROPENAEUS CHINENSIS%光色对中国明对虾(Fenneropenaeus chinensis)稚虾耗氧率昼夜变化节律的影响

    Institute of Scientific and Technical Information of China (English)

    刘伟; 王芳; 钟大森; 黄国强

    2011-01-01

    The effect of light colour on the diel rhythm of the oxygen consumption rate in ju venile Fenneropenaeus chinensis with average wet body weight of (5. 507 ±0. 147)g was ex amined under a flowing water apparatus at 25. 0±0. 5℃, and the four light colours were: natural light (590nm), yellow light (580nm), green light (525 nm), and blue light (435nm) . Respectively. The results were as follows: 1 under natural light, yellow light, and green light, the oxygen consumption rate of F. Chinensis showed definite diel rhythm, the positive peak appeared at dark condition, while the negative peak appeared at illumination condition. Mean oxygen consumption rate of F. Chinensis at dark condition was significantly higher than that at illumination one (P0. 05), but the diurnal mean oxygen consumption rate of F. Chinensis under natural light was significantly lower than that under blue light treatment.%采用流水装置测定了中国明对虾(Fenneropenaeus chinensis)稚虾在4种先色处理下耗氧率的昼夜变化.实验设四种光色处理,分别为自然光(590nm)、黄光(580nm)、绿光(525 nm)和蓝光(435nm),光照周期为14L:10D,水温为25.0±0.5℃,实验虾的规格为(5.507±0.147)g.主要实验结果如下:1、在自然光、黄光和绿光下,中国明对虾耗氧率的昼夜波动较大,对虾耗氧率的高峰出现在夜间,低谷出现在日间,且对虾在夜间的平均耗氧率显著高于日间(P<0.05);在蓝光下,中国明对虾耗氧率的昼夜波动较小,对虾耗氧率的高峰出现在日间,低谷出现在夜间,且对虾在夜间和日间的平均耗氧率差异不显著(P>0.05);2、在自然光、黄光和绿光下,中国明对虾的日平均耗氧率差异不昱著(P>0.05),而对虾日平均耗氧率在蓝光和自然光下的差异显著(P<0.05).

  10. Pharmaceutical preparation of oxygen-15 labelled molecular oxygen and carbon monoxide gasses in a hospital setting.

    NARCIS (Netherlands)

    Luurtsema, Geert; Boellaard, Ronald; Greuter, Henri; Rijbroek, Abraham; Takkenkamp, Kevin; de Geest, Frank; Buijs, Fred; Hendrikse, NH; Franssen, Eric; van Lingen, Arthur; Lammertsma, Adriaan A.

    BACKGROUND: Clinical positron emission tomography (PET) requires safe and effective PET radiopharmaceuticals. Tracers used for measuring oxygen consumption and blood volume are [(15)O]O(2) and [(15)O]CO, respectively. In general, these oxygen-15 labelled tracers are produced using a cyclotron that

  11. Early diagenesis in the Congo deep-sea fan sediments dominated by massive terrigenous deposits: Part I - Oxygen consumption and organic carbon mineralization using a micro-electrode approach

    Science.gov (United States)

    Pozzato, Lara; Cathalot, Cécile; Berrached, Chabha; Toussaint, Flora; Stetten, Elsa; Caprais, Jean-Claude; Pastor, Lucie; Olu, Karine; Rabouille, Christophe

    2017-08-01

    Organic matter (OM) transfer from the continent to the ocean occurs across margins which constitute a major area of OM recycling and burial. The lobe complex of the Congo deep-sea fan is connected to the river mouth by a canyon and alimented by recurrent turbidity currents, containing a large proportion of labile terrigenous OM and producing high sedimentation rates. These inputs support the development of ecosystems harboring rich assemblages of vesicomyid bivalves and bacterial mats, called Habitats. Here, we present O2 microprofiles and diffusive oxygen uptake rates (DOUs) obtained during the CONGOLOBE project at six sites of this active lobe complex by in situ and on-board methods based on micro-electrode profiling. The dataset is used to determine remineralization rates and study the biogeochemical dynamics of different ecosystems of the lobe area, in order to compare levee and background sediments to the Habitats developed on the flanks of the main turbiditic channel. Levee and background sediments are characterized by significantly higher DOUs than abyssal sediments at 5000 m meters depth (2-5 mmol O2 m-2 d-1versus 1.5-2.5 mmol O2 m-2 d-1) and the Habitats are hotspots of OM remineralization with DOU values ranging between 8 and 40 mmol O2 m-2 d-1. By comparing sites near the active channel to a site located 50 km away, we show that the lobe connection to the main turbiditic channel is vital to the dense benthic communities.

  12. Muscle injury after low-intensity downhill running reduces running economy.

    Science.gov (United States)

    Baumann, Cory W; Green, Michael S; Doyle, J Andrew; Rupp, Jeffrey C; Ingalls, Christopher P; Corona, Benjamin T

    2014-05-01

    Contraction-induced muscle injury may reduce running economy (RE) by altering motor unit recruitment, lowering contraction economy, and disturbing running mechanics, any of which may have a deleterious effect on endurance performance. The purpose of this study was to determine if RE is reduced 2 days after performing injurious, low-intensity exercise in 11 healthy active men (27.5 ± 5.7 years; 50.05 ± 1.67 VO2peak). Running economy was determined at treadmill speeds eliciting 65 and 75% of the individual's peak rate of oxygen uptake (VO2peak) 1 day before and 2 days after injury induction. Lower extremity muscle injury was induced with a 30-minute downhill treadmill run (6 × 5 minutes runs, 2 minutes rest, -12% grade, and 12.9 km·h(-1)) that elicited 55% VO2peak. Maximal quadriceps isometric torque was reduced immediately and 2 days after the downhill run by 18 and 10%, and a moderate degree of muscle soreness was present. Two days after the injury, steady-state VO2 and metabolic work (VO2 L·km(-1)) were significantly greater (4-6%) during the 65% VO2peak run. Additionally, postinjury VCO2, VE and rating of perceived exertion were greater at 65% but not at 75% VO2peak, whereas whole blood-lactate concentrations did not change pre-injury to postinjury at either intensity. In conclusion, low-intensity downhill running reduces RE at 65% but not 75% VO2peak. The results of this study and other studies indicate the magnitude to which RE is altered after downhill running is dependent on the severity of the injury and intensity of the RE test.

  13. CHANGES IN PAIN PERCEPTION IN WOMEN DURING AND FOLLOWING AN EXHAUSTIVE INCREMENTAL CYCLING EXERCISE

    Directory of Open Access Journals (Sweden)

    Daniel G. Drury

    2005-09-01

    Full Text Available Exercise has been found to alter pain sensitivity with a hypoalgesic response (i.e., diminished sensitivity to pain typically reported during and/or following high intensity exercise. Most of this research, however, has involved the testing of men. Thus, the purpose of the following investigation was to examine changes in pain perception in women during and following exercise. Seventeen healthy female subjects (age 20.47±.87; VO2 peak 36.77± 4.95 volunteered to undergo pain assessment prior to, during, and after a graded exhaustive VO2 peak cycling challenge. Heart Rate (HR and Oxygen Uptake (VO2 were monitored along with electro-diagnostic assessments of Pain Threshold (PT and Pain Tolerance (PTOL at: 1 baseline (B, 2 during exercise (i.e., 120 Watts, 3 at exhaustive intensity (VO2 peak, and 4 10 minutes into recovery (R. Data were analyzed using repeated measures ANOVA to determine differences across trials. Significant differences in PT and PTOL were found across trials (PT, p = 0.0043; PTOL p = 0.0001. Post hoc analyses revealed that PT were significantly elevated at VO2 peak in comparison to B (p = 0.007, 120 Watts (p = 0.0178 and R (p = 0.0072. PTOL were found to be significantly elevated at 120 Watts (p = 0.0247, VO2 peak (p < 0.001, and R (p = 0.0001 in comparison to B. In addition, PTOL were found to be significantly elevated at VO2 peak in comparison to 120 Watts (p = 0.0045. It is concluded that exercise-induced hypoalgesia occurs in women during and following exercise, with the hypoalgesic response being most pronounced following exhaustive exercise

  14. Oxygen dependence of respiration in rat spinotrapezius muscle in situ

    OpenAIRE

    Golub, Aleksander S.; Pittman, Roland N.

    2012-01-01

    The oxygen dependence of respiration in striated muscle in situ was studied by measuring the rate of decrease of interstitial Po2 [oxygen disappearance curve (ODC)] following rapid arrest of blood flow by pneumatic tissue compression, which ejected red blood cells from the muscle vessels and made the ODC independent from oxygen bound to hemoglobin. After the contribution of photo-consumption of oxygen by the method was evaluated and accounted for, the corrected ODCs were converted into the Po...

  15. Oxygen depletion of bismuth molybdates

    Energy Technology Data Exchange (ETDEWEB)

    Yong, L.K.; Howe, R.F.; Keulks, G.W.; Hall, W.K.

    1978-05-01

    Pure ..cap alpha..-phase bismuth molybdate (Bi/sub 2/Mo/sub 3/O/sub 12/), which is known to be weakly active for selective oxidation, and pure ..gamma..-phase bismuth molybdate (Bi/sub 2/MoO/sub 6/), which has good activity, were subjected to oxidation-reduction cycles with known amounts of hydrogen and oxygen, at 300/sup 0/-570/sup 0/C and with evacuation steps between treatments. The volume of oxygen consumed during reoxidation was equal to half the hydrogen consumed during the reduction on the ..cap alpha..-phase, which indicated that no hydrogen was retained during reduction. For the ..gamma..-phase, the oxygen consumption was greater than half of the hydrogen consumption and it increased with extent of reduction. The excess oxygen was apparently consumed by filling anion vacancies formed during outgassing subsequent to the reduction step. ESR spectroscopy and temperature-programed oxidation-reduction indicated that lattice oxide ions which bridge between bismuth and molybdenum layers of the koechlinite structure become more labile when the catalyst is in a partially reduced state, and that this effect is greater in the ..gamma..- than the ..cap alpha..-phase. Table and 15 references.

  16. Contraction-mediated glucose uptake is increased in men with impaired glucose tolerance

    DEFF Research Database (Denmark)

    Skov-Jensen, Camilla; Skovbro, Mette; Flint, Anne

    2007-01-01

    stimulation alone and with superimposed exercise. Patients with type 2 diabetes, subjects with impaired glucose tolerance (IGT), healthy controls, and endurance-trained subjects were studied. The groups were matched for age and lean body mass (LBM), and differed in peak oxygen uptake (VO2 peak), body fat...

  17. Development of an integrated countermeasure device for use in long-duration spaceflight

    Science.gov (United States)

    Streeper, T.; Cavanagh, P. R.; Hanson, A. M.; Carpenter, R. D.; Saeed, I.; Kornak, J.; Frassetto, L.; Grodsinsky, C.; Funk, J.; Lee, S. M. C.; Spiering, B. A.; Bloomberg, J.; Mulavara, A.; Sibonga, J.; Lang, T.

    2011-06-01

    Prolonged weightlessness is associated with declines in musculoskeletal, cardiovascular, and sensorimotor health. Consequently, in-flight countermeasures are required to preserve astronaut health. We developed and tested a novel exercise countermeasure device (CCD) for use in spaceflight with the aim of preserving musculoskeletal and cardiovascular health along with an incorporated balance training component. Additionally, the CCD features a compact footprint, and a low power requirement. Methods: After design and development of the CCD, we carried out a training study to test its ability to improve cardiovascular and muscular fitness in healthy volunteers. Fourteen male and female subjects (41.4±9.0 years, 69.5±15.4 kg) completed 12 weeks (3 sessions per week) of concurrent strength and endurance training on the CCD. All training was conducted with the subject in orthostasis. When configured for spaceflight, subjects will be fixed to the device via a vest with loop attachments secured to subject load devices. Subjects were tested at baseline and after 12 weeks for 1-repetition max leg press strength (1RM), peak oxygen consumption (VO 2peak), and isokinetic joint torque (ISO) at the hip, knee, and ankle. Additionally, we evaluated subjects after 6 weeks of training for changes in VO 2peak and 1RM. Results: VO 2peak and 1RM improved after 6 weeks, with additional improvements after 12 weeks (1.95±0.5, 2.28±0.5, 2.47±0.6 L min -1, and 131.2±63.9,182.8±75.0, 207.0±75.0 kg) for baseline, 6 weeks, and 12 weeks, respectively. ISO for hip adduction, adduction, and ankle plantar flexion improved after 12 weeks of training (70.3±39.5, 76.8±39.2, and 55.7±21.7 N m vs. 86.1±37.3, 85.1±34.3, and 62.1±26.4 N m, respectively). No changes were observed for ISO during hip flexion, knee extension, or knee flexion. Conclusions: The CCD is effective at improving cardiovascular fitness and isotonic leg strength in healthy adults. Further, the improvement in hip adductor

  18. Energy consumption: energy consumption in mainland Norway

    Energy Technology Data Exchange (ETDEWEB)

    Magnussen, Inger Helene; Killingland, Magnus; Spilde, Dag

    2012-07-25

    The purpose of this report is to describe trends in energy consumption in mainland Norway, with an emphasis on key trends within the largest consumer groups. We also explain common terms and concepts in the field of energy consumption. Finally, we look at forecasts for future energy consumption, produced by bodies outside NVE. Total final energy consumption in mainland Norway in 2009 was 207 TWh. The most important end-user groups are households, service industries, manufacturing industry and transport. In addition, the energy sector in mainland Norway consumed 15 TWh. Energy consumed in the energy sector is not considered as final consumption, as the energy is used to produce new energy products. The long-term trend in energy consumption in mainland Norway is that fuel in the transport sector and electricity for the energy sector increases, while energy consumption in other sectors flattens out. The main reason for an increased use of fuel in the transport sector is the rise in the number of motorised machinery and vehicles in mainland Norway. This has caused a rise in gasoline and diesel consumption of 75 per cent since 1976. The petroleum sector is the largest consumer of energy within the energy sector in mainland Norway, and electricity from onshore to platforms in the North Sea and to new shore side installations has led to a rise in electricity consumption from 1 TWh in 1995 to 5 TWh in 2009. The energy consumption in households showed flat trend from 1996 to 2009, after many years of growth. The main reasons are a warmer climate, higher energy prices, the use of heats pumps and more energy-efficient buildings. In the service industries, the growth in energy consumptions has slightly decreased since the late 1990s, for much the same reasons as for households. In manufacturing industries the energy consumption have flatten out mainly due to the closure of energy-intensive businesses and the establishment of new more energy-efficient businesses. Electricity is

  19. El ejercicio físico aeróbico incrementa la vasodilatación dependiente del endotelio y el consumo de oxígeno de mujeres primigestantes saludables. Ensayo clínico controlado, aleatorizado. NCT00741312 Aerobic physical exercise increases endothelium-dependent vasodilation and oxygen consumption in healthy primigravida. Controlled randomized clinical trial. NCT00741312

    Directory of Open Access Journals (Sweden)

    Róbinson Ramírez-Vélez

    2010-12-01

    Full Text Available OBJETIVO: evaluar el efecto del ejercicio aeróbico en la función dependiente del endotelio (VDE y en el consumo de oxígeno en mujeres primigestantes. MÉTODOS: ensayo clínico controlado, enmascarado y aleatorizado, llevado a cabo en 67 mujeres saludables, primigestantes, entre 16 a 20 semanas de gestación. Grupo de intervención: ejercicio aeróbico entre 50% y 65% de la frecuencia cardiaca máxima, durante 45 minutos, tres veces por semana, durante dieciséis semanas. Grupo control: actividad física habitual. Mediciones: VDE: vasodilatación mediada por flujo (VMF, consumo de oxígeno VO2max: prueba de caminata de seis minutos; antropometría: peso y talla. RESULTADOS: en las mediciones iniciales no se encontraron diferencias entre grupos en ninguna de las variables. Al finalizar la intervención, las participantes que realizaron ejercicio tenían mayor capacidad física, medida por la distancia recorrida en el test de caminata (p=0,043 y por el VO2max (p=0,023. Además, el grupo de ejercicio tuvo menor frecuencia cardiaca en reposo y mayor VMF que el grupo control (pOBJECTIVE: evaluate the effect of aerobic exercise on endothelium-dependent function (EDF and oxygen consumption in primigravida. METHODS: double-blind, randomized controlled clinical trial carried out in primigravida between 16 to 20 weeks of gestation. The intervention group had aerobic exercise between 50% to 65% of the maximum heart rate during 45 minutes, three times a week for sixteen weeks. The control group had habitual physical activity. MEASUREMENTS REALIZED: EDF: flow-mediated dilation (FMD, oxygen consumption VO2max: 6 minute walking test, anthropometry: weight and size. RESULTS: no differences were found between the two groups in any variables in the initial measurements. At the end of the intervention, participants who exercised had greater physical capacity, measured by the distance covered in walking test (p = 0.043 and VO2max (p = 0.023. In addition, the

  20. Consumption Habits and Humps

    DEFF Research Database (Denmark)

    Kraft, Holger; Munk, Claus; Seifried, Frank Thomas

    2017-01-01

    We show that the optimal consumption of an individual over the life cycle can have the hump shape (inverted U-shape) observed empirically if the preferences of the individual exhibit internal habit formation. In the absence of habit formation, an impatient individual would prefer a decreasing...... consumption path over life. However, because of habit formation, a high initial consumption would lead to high required consumption in the future. To cover the future required consumption, wealth is set aside, but the necessary amount decreases with age which allows consumption to increase in the early part...... of life. At some age, the impatience outweighs the habit concerns so that consumption starts to decrease. We derive the optimal consumption strategy in closed form, deduce sufficient conditions for the presence of a consumption hump, and characterize the age at which the hump occurs. Numerical examples...

  1. Consumption Habits and Humps

    DEFF Research Database (Denmark)

    Kraft, Holger; Munk, Claus; Seifried, Frank Thomas

    We show that the optimal consumption of an individual over the life cycle can have the hump shape (inverted U-shape) observed empirically if the preferences of the individual exhibit internal habit formation. In the absence of habit formation, an impatient individual would prefer a decreasing...... consumption path over life. However, because of habit formation, a high initial consumption would lead to high required consumption in the future. To cover the future required consumption, wealth is set aside, but the necessary amount decreases with age which allows consumption to increase in the early part...... of life. At some age, the impatience outweighs the habit concerns so that consumption starts to decrease. We derive the optimal consumption strategy in closed form, deduce sufficient conditions for the presence of a consumption hump, and characterize the age at which the hump occurs. Numerical examples...

  2. Nitric Oxide is Required for Homeostasis of Oxygen and Reactive Oxygen Species in Barley Roots under Aerobic Conditions

    DEFF Research Database (Denmark)

    Gupta, Kapuganti J; Hebelstrup, Kim; Kruger, Nicholas J

    2014-01-01

    Oxygen, the terminal electron acceptor for mitochondrial electron transport, is vital for plants because of its role in the production of ATP by oxidative phosphorylation. While photosynthetic oxygen production contributes to the oxygen supply in leaves, reducing the risk of oxygen limitation of ...... electron transport chain (Gupta et al., 2011). Thus, NO could influence oxygen consumption under normal aerobic conditions in roots, and it is this specific function that is assessed here.......Oxygen, the terminal electron acceptor for mitochondrial electron transport, is vital for plants because of its role in the production of ATP by oxidative phosphorylation. While photosynthetic oxygen production contributes to the oxygen supply in leaves, reducing the risk of oxygen limitation...

  3. Lifetime of the internal reference oxygen sensor

    DEFF Research Database (Denmark)

    Hu, Qiang; Jacobsen, Torben; Hansen, Karin Vels

    2013-01-01

    The internal reference oxygen sensor (IROS) based on a binary mixture of metal and its stoichiometric oxide is subject to leaks that result in consumption of the binary mixture. An IROS loses the functionality when the binary mixture is exhausted. Among the possible leak sources the electronic leak...

  4. Energy Consumption Database

    Science.gov (United States)

    Consumption Database The California Energy Commission has created this on-line database for informal reporting ) classifications. The database also provides easy downloading of energy consumption data into Microsoft Excel (XLSX

  5. Effect of Folk Dance Training on Blood Oxidative Stress Level, Lipids, and Lipoproteins

    Directory of Open Access Journals (Sweden)

    Okdan Bora

    2016-09-01

    Full Text Available Introduction. Folk dance is a form of physical activity which helps develop the ability to use the whole body in a coordinated way with music, and folk dancers’ characteristics vary according to the particular type of dance practised in a given geographic region. The aims of the study were to evaluate the effects of 12-week folk dance training on blood oxidative stress level, lipids, lipoproteins, as well as muscle damage markers and to define some physical and physiological properties of folk dancers. Material and methods. Thirty-eight healthy male folk dancers aged 21-28 years having an average of 11 years of dance training experience voluntarily participated in the study. All of the physical and physiological measurements and the blood analysis were performed twice, before and after the training period which focused on different regional dances (Caucasus, Bar, Zeybek, Spoon Dance, Thracian dances, and Horon. The training was done 2 hours per day (a total of 10 hours a week, during a 12-week-long period. Results. All the blood parameters were found to be within the specified reference ranges. The training programme had no significant effect on the blood lipid profile, whereas it was found to have positive effects on body fat (p ≤ 0.012, peak oxygen consumption (VO2peak; p = 0.000, muscle damage markers (creatine kinase, Δ% = −19.6, and total antioxidant capacity (p ≤ 0.002. Conclusions. Regular folk dance training was found to have positive effects on body fat, VO2peak, blood total antioxidant capacity, and muscle damage markers. Based on these results, the community should be encouraged to perform folk dance as a recreational physical activity, and public awareness should be raised about the health benefits of practising folk dances.

  6. Feasibility, safety, and efficacy of aerobic training in pretreated patients with metastatic breast cancer: A randomized controlled trial.

    Science.gov (United States)

    Scott, Jessica M; Iyengar, Neil M; Nilsen, Tormod S; Michalski, Meghan; Thomas, Samantha M; Herndon, James; Sasso, John; Yu, Anthony; Chandarlapaty, Sarat; Dang, Chau T; Comen, Elizabeth A; Dickler, Maura N; Peppercorn, Jeffrey M; Jones, Lee W

    2018-04-06

    The investigation of exercise training in metastatic breast cancer has received minimal attention. This study determined the feasibility and safety of aerobic training in metastatic breast cancer. Sixty-five women (age, 21-80 years) with metastatic (stage IV) breast cancer (57% were receiving chemotherapy, and >40% had ≥ 2 lines of prior therapy) were allocated to an aerobic training group (n = 33) or a stretching group (n = 32). Aerobic training consisted of 36 supervised treadmill walking sessions delivered thrice weekly between 55% and 80% of peak oxygen consumption (VO 2peak ) for 12 consecutive weeks. Stretching was matched to aerobic training with respect to location, frequency, duration, and intervention length. The primary endpoint was aerobic training feasibility, which was a priori defined as the lost to follow-up (LTF) rate (aerobic training was LTF, whereas the mean attendance rate was 63% ± 30%. The rates of permanent discontinuation and dose modification were 27% and 49%, respectively. Intention-to-treat analyses indicated improvements in PROs, which favored the attention control group (P values > .05). Per protocol analyses indicated that 14 of 33 patients (42%) receiving aerobic training had acceptable tolerability (relative dose intensity ≥ 70%), and this led to improvements in VO 2peak and functional capacity (P values Aerobic training at the dose and schedule tested is safe but not feasible for a significant proportion of patients with metastatic breast cancer. The acceptable feasibility and promising benefit for select patients warrant further evaluation in a dose-finding phase 1/2 study. Cancer 2018. © 2018 American Cancer Society. © 2018 American Cancer Society.

  7. Alternatives to the six-minute walk test in pulmonary arterial hypertension.

    Directory of Open Access Journals (Sweden)

    Vincent Mainguy

    Full Text Available INTRODUCTION: The physiological response during the endurance shuttle walk test (ESWT, the cycle endurance test (CET and the incremental shuttle walk test (ISWT remains unknown in PAH. We tested the hypothesis that endurance tests induce a near-maximal physiological demand comparable to incremental tests. We also hypothesized that differences in respiratory response during exercise would be related to the characteristics of the exercise tests. METHODS: Within two weeks, twenty-one PAH patients (mean age: 54(15 years; mean pulmonary arterial pressure: 42(12 mmHg completed two cycling exercise tests (incremental cardiopulmonary cycling exercise test (CPET and CET and three field tests (ISWT, ESWT and six-minute walk test (6MWT. Physiological parameters were continuously monitored using the same portable telemetric device. RESULTS: Peak oxygen consumption (VO(2peak was similar amongst the five exercise tests (p = 0.90 by ANOVA. Walking distance correlated markedly with the VO(2peak reached during field tests, especially when weight was taken into account. At 100% exercise, most physiological parameters were similar between incremental and endurance tests. However, the trends overtime differed. In the incremental tests, slopes for these parameters rose steadily over the entire duration of the tests, whereas in the endurance tests, slopes rose sharply from baseline to 25% of maximum exercise at which point they appeared far less steep until test end. Moreover, cycling exercise tests induced higher respiratory exchange ratio, ventilatory demand and enhanced leg fatigue measured subjectively and objectively. CONCLUSION: Endurance tests induce a maximal physiological demand in PAH. Differences in peak respiratory response during exercise are related to the modality (cycling vs. walking rather than the progression (endurance vs. incremental of the exercise tests.

  8. Alternatives to the six-minute walk test in pulmonary arterial hypertension.

    Science.gov (United States)

    Mainguy, Vincent; Malenfant, Simon; Neyron, Anne-Sophie; Saey, Didier; Maltais, François; Bonnet, Sébastien; Provencher, Steeve

    2014-01-01

    The physiological response during the endurance shuttle walk test (ESWT), the cycle endurance test (CET) and the incremental shuttle walk test (ISWT) remains unknown in PAH. We tested the hypothesis that endurance tests induce a near-maximal physiological demand comparable to incremental tests. We also hypothesized that differences in respiratory response during exercise would be related to the characteristics of the exercise tests. Within two weeks, twenty-one PAH patients (mean age: 54(15) years; mean pulmonary arterial pressure: 42(12) mmHg) completed two cycling exercise tests (incremental cardiopulmonary cycling exercise test (CPET) and CET) and three field tests (ISWT, ESWT and six-minute walk test (6MWT)). Physiological parameters were continuously monitored using the same portable telemetric device. Peak oxygen consumption (VO(2peak)) was similar amongst the five exercise tests (p = 0.90 by ANOVA). Walking distance correlated markedly with the VO(2peak) reached during field tests, especially when weight was taken into account. At 100% exercise, most physiological parameters were similar between incremental and endurance tests. However, the trends overtime differed. In the incremental tests, slopes for these parameters rose steadily over the entire duration of the tests, whereas in the endurance tests, slopes rose sharply from baseline to 25% of maximum exercise at which point they appeared far less steep until test end. Moreover, cycling exercise tests induced higher respiratory exchange ratio, ventilatory demand and enhanced leg fatigue measured subjectively and objectively. Endurance tests induce a maximal physiological demand in PAH. Differences in peak respiratory response during exercise are related to the modality (cycling vs. walking) rather than the progression (endurance vs. incremental) of the exercise tests.

  9. Novel all-extremity high-intensity interval training improves aerobic fitness, cardiac function and insulin resistance in healthy older adults.

    Science.gov (United States)

    Hwang, Chueh-Lung; Yoo, Jeung-Ki; Kim, Han-Kyul; Hwang, Moon-Hyon; Handberg, Eileen M; Petersen, John W; Christou, Demetra D

    2016-09-01

    Aging is associated with decreased aerobic fitness and cardiac remodeling leading to increased risk for cardiovascular disease. High-intensity interval training (HIIT) on the treadmill has been reported to be more effective in ameliorating these risk factors compared with moderate-intensity continuous training (MICT) in patients with cardiometabolic disease. In older adults, however, weight-bearing activities are frequently limited due to musculoskeletal and balance problems. The purpose of this study was to examine the feasibility and safety of non-weight-bearing all-extremity HIIT in older adults. In addition, we tested the hypothesis that all-extremity HIIT will be more effective in improving aerobic fitness, cardiac function, and metabolic risk factors compared with all-extremity MICT. Fifty-one healthy sedentary older adults (age: 65±1years) were randomized to HIIT (n=17), MICT (n=18) or non-exercise control (CONT; n=16). HIIT (4×4min 90% of peak heart rate; HRpeak) and isocaloric MICT (70% of HRpeak) were performed on a non-weight-bearing all-extremity ergometer, 4×/week for 8weeks under supervision. All-extremity HIIT was feasible in older adults and resulted in no adverse events. Aerobic fitness (peak oxygen consumption; VO2peak) and ejection fraction (echocardiography) improved by 11% (PHIIT, while no changes were observed in MICT and CONT (P≥0.1). Greater improvements in ejection fraction were associated with greater improvements in VO2peak (r=0.57; PHIIT by 26% (P=0.016). Diastolic function, body composition, glucose and lipids were unaffected (P≥0.1). In conclusion, all-extremity HIIT is feasible and safe in older adults. HIIT, but not MICT, improved aerobic fitness, ejection fraction, and insulin resistance. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Preoperative gender differences in pulmonary gas exchange in morbidly obese subjects.

    Science.gov (United States)

    Zavorsky, Gerald S; Christou, Nicolas V; Kim, Do Jun; Carli, Franco; Mayo, Nancy E

    2008-12-01

    Morbidly obese men may have poorer pulmonary gas exchange compared to morbidly obese women (see Zavorsky et al., Chest 131:362-367, 2007). The purpose was to compare pulmonary gas exchange in morbidly obese men and women at rest and throughout exercise. Twenty-five women (age=38+/-10 years, 164+/-7 cm, body mass index or BMI = 51+/-7 kg/m(2), peak oxygen consumption or VO(2peak)=2.0+/-0.4 l/min) and 17 men (age=43+/-9 years, 178+/-7 cm, BMI=50+/-10 kg/m(2), VO(2peak)=2.6+/-0.8 l/min) were recruited to perform a graded exercise test on a cycle ergometer with temperature-corrected arterial blood-gas samples taken at rest and every minute of exercise, including peak exercise. At rest, women were 98% predicted for pulmonary diffusion compared to 88% predicted in men. At rest, women had better pulmonary gas exchange compared to the men which was related to women having a lower waist-to-hip ratio (WHR; por=25 mmHg) at peak exercise, but 75% of the subjects showed inadequate compensatory hyperventilation at peak exercise (arterial carbon dioxide pressure >35 mmHg), and both were not different between genders. At rest, morbidly obese men have poorer pulmonary gas exchange and pulmonary diffusion compared to morbidly obese women. The better gas exchange in women is related to the lower WHR in the women. During exercise, few subjects showed disturbances in pulmonary gas exchange despite demonstrating poor compensatory hyperventilation at peak exercise.

  11. Novel All-Extremity High-Intensity Interval Training Improves Aerobic Fitness, Cardiac Function and Insulin Resistance in Healthy Older Adults

    Science.gov (United States)

    Hwang, Chueh-Lung; Yoo, Jeung-Ki; Kim, Han-Kyul; Hwang, Moon-Hyon; Handberg, Eileen M.; Petersen, John W.; Christou, Demetra D.

    2016-01-01

    Aging is associated with decreased aerobic fitness and cardiac remodeling leading to increased risk for cardiovascular disease. High-intensity interval training (HIIT) on the treadmill has been reported to be more effective in ameliorating these risk factors compared with moderate-intensity continuous training (MICT) in patients with cardiometabolic disease. In older adults, however, weight-bearing activities are frequently limited due to musculoskeletal and balance problems. The purpose of this study was to examine the feasibility and safety of non-weight-bearing all-extremity HIIT in older adults. In addition, we tested the hypothesis that all-extremity HIIT will be more effective in improving aerobic fitness, cardiac function, and metabolic risk factors compared with all-extremity MICT. Fifty-one healthy sedentary older adults (age: 65±1 years) were randomized to HIIT (n=17), MICT (n=18) or non-exercise control (CONT; n=16). HIIT (4×4 minutes 90% of peak heart rate; HRpeak) and isocaloric MICT (70% of HRpeak) were performed on a non-weight-bearing all-extremity ergometer, 4x/week for 8 weeks under supervision. All-extremity HIIT was feasible in older adults and resulted in no adverse events. Aerobic fitness (peak oxygen consumption; VO2peak) and ejection fraction (echocardiography) improved by 11% (PHIIT, while no changes were observed in MICT and CONT (P≥0.1). Greater improvements in ejection fraction were associated with greater improvements in VO2peak (r=0.57; PHIIT by 26% (P=0.016). Diastolic function, body composition, glucose and lipids were unaffected (P≥0.1). In conclusion, all-extremity HIIT is feasible and safe in older adults. HIIT, but not MICT, improved aerobic fitness, ejection fraction, and insulin resistance. PMID:27346646

  12. The Acute Effects of Interval-Type Exercise on Glycemic Control in Type 2 Diabetes Subjects: Importance of Interval Length. A Controlled, Counterbalanced, Crossover Study.

    Directory of Open Access Journals (Sweden)

    Ida Jakobsen

    Full Text Available Interval-type exercise is effective for improving glycemic control, but the optimal approach is unknown. The purpose of this study was to determine the importance of the interval length on changes in postprandial glycemic control following a single exercise bout. Twelve subjects with type 2 diabetes completed a cross-over study with three 1-hour interventions performed in a non-randomized but counter-balanced order: 1 Interval walking consisting of repeated cycles of 3 min slow (aiming for 54% of Peak oxygen consumption rate [VO2peak] and 3 min fast (aiming for 89% of VO2peak walking (IW3; 2 Interval walking consisting of repeated cycles of 1 min slow and 1 min fast walking (IW1 and 3 No walking (CON. The exercise interventions were matched with regards to walking speed, and VO2 and heart rate was assessed throughout all interventions. A 4-hour liquid mixed meal tolerance test commenced 30 min after each intervention, with blood samples taken regularly. IW3 and IW1 resulted in comparable mean VO2 and heart rates. Overall mean postprandial blood glucose levels were lower after IW3 compared to CON (10.3±3.0 vs. 11.1±3.3 mmol/L; P 0.05 for both. Conversely blood glucose levels at specific time points during the MMTT differed significantly following both IW3 and IW1 as compared to CON. Our findings support the previously found blood glucose lowering effect of IW3 and suggest that reducing the interval length, while keeping the walking speed and time spend on fast and slow walking constant, does not result in additional improvements.ClinicalTrials.gov NCT02257190.

  13. Effects of obstructive sleep apnea and obesity on exercise function in children.

    Science.gov (United States)

    Evans, Carla A; Selvadurai, Hiran; Baur, Louise A; Waters, Karen A

    2014-06-01

    Evaluate the relative contributions of weight status and obstructive sleep apnea (OSA) to cardiopulmonary exercise responses in children. Prospective, cross-sectional study. Participants underwent anthropometric measurements, overnight polysomnography, spirometry, cardiopulmonary exercise function testing on a cycle ergometer, and cardiac doppler imaging. OSA was defined as ≥ 1 obstructive apnea or hypopnea per hour of sleep (OAHI). The effect of OSA on exercise function was evaluated after the parameters were corrected for body mass index (BMI) z-scores. Similarly, the effect of obesity on exercise function was examined when the variables were adjusted for OAHI. Tertiary pediatric hospital. Healthy weight and obese children, aged 7-12 y. N/A. Seventy-one children were studied. In comparison with weight-matched children without OSA, children with OSA had a lower cardiac output, stroke volume index, heart rate, and oxygen consumption (VO2 peak) at peak exercise capacity. After adjusting for BMI z-score, children with OSA had 1.5 L/min (95% confidence interval -2.3 to -0.6 L/min; P = 0.001) lower cardiac output at peak exercise capacity, but minute ventilation and ventilatory responses to exercise were not affected. Obesity was only associated with physical deconditioning. Cardiac dysfunction was associated with the frequency of respiratory-related arousals, the severity of hypoxia, and heart rate during sleep. Children with OSA are exercise limited due to a reduced cardiac output and VO2 peak at peak exercise capacity, independent of their weight status. Comorbid OSA can further decrease exercise performance in obese children.

  14. Does recombinant human Epo increase exercise capacity by means other than augmenting oxygen transport?

    DEFF Research Database (Denmark)

    Lundby, C; Robach, P; Boushel, R

    2008-01-01

    This study was performed to test the hypothesis that administration of recombinant human erythropoietin (rHuEpo) in humans increases maximal oxygen consumption by augmenting the maximal oxygen carrying capacity of blood. Systemic and leg oxygen delivery and oxygen uptake were studied during...... before rHuEpo treatment). Blood buffer capacity remained unaffected by rHuEpo treatment and hemodilution. The augmented hematocrit did not compromise peak cardiac output. In summary, in healthy humans, rHuEpo increases maximal oxygen consumption due to augmented systemic and muscular peak oxygen delivery....

  15. Placental Gas Exchange and the Oxygen Supply to the Fetus

    DEFF Research Database (Denmark)

    Carter, Anthony M

    2015-01-01

    The oxygen supply of the fetus depends on the blood oxygen content and flow rate in the uterine and umbilical arteries and the diffusing capacity of the placenta. Oxygen consumption by the placenta is a significant factor and a potential limitation on availability to the fetus. The relevance...... anaerobic conditions and even the fetus is adapted to a low oxygen environment. Nevertheless, there is a reserve capacity, and during acute hypoxia the fetus can counter a 50% reduction in oxygen delivery by increasing fractional extraction. During sustained hypoxia, on the other hand, fetal growth...

  16. Modeling and experimental methods to predict oxygen distribution in bone defects following cell transplantation.

    Science.gov (United States)

    Heylman, Christopher M; Santoso, Sharon; Krebs, Melissa D; Saidel, Gerald M; Alsberg, Eben; Muschler, George F

    2014-04-01

    We have developed a mathematical model that allows simulation of oxygen distribution in a bone defect as a tool to explore the likely effects of local changes in cell concentration, defect size or geometry, local oxygen delivery with oxygen-generating biomaterials (OGBs), and changes in the rate of oxygen consumption by cells within a defect. Experimental data for the oxygen release rate from an OGB and the oxygen consumption rate of a transplanted cell population are incorporated into the model. With these data, model simulations allow prediction of spatiotemporal oxygen concentration within a given defect and the sensitivity of oxygen tension to changes in critical variables. This information may help to minimize the number of experiments in animal models that determine the optimal combinations of cells, scaffolds, and OGBs in the design of current and future bone regeneration strategies. Bone marrow-derived nucleated cell data suggest that oxygen consumption is dependent on oxygen concentration. OGB oxygen release is shown to be a time-dependent function that must be measured for accurate simulation. Simulations quantify the dependency of oxygen gradients in an avascular defect on cell concentration, cell oxygen consumption rate, OGB oxygen generation rate, and OGB geometry.

  17. Muscle mitochondrial capacity exceeds maximal oxygen delivery in humans

    DEFF Research Database (Denmark)

    Boushel, Robert Christopher; Gnaiger, Erich; Calbet, Jose A L

    2011-01-01

    Across a wide range of species and body mass a close matching exists between maximal conductive oxygen delivery and mitochondrial respiratory rate. In this study we investigated in humans how closely in-vivo maximal oxygen consumption (VO(2) max) is matched to state 3 muscle mitochondrial respira...

  18. Oxygen consumption in Mediterranean octocorals under different temperatures

    NARCIS (Netherlands)

    Previati, M.; Scinto, A.; Cerrano, C.; Osinga, R.

    2010-01-01

    Ecosystem resilience to climate anomalies is related to the physiological plasticity of organisms. To characterize the physiological response of some common Mediterranean gorgonians to fluctuations in temperature, four species (Paramuricea clavata, Eunicella singularis, Eunicella cavolinii and

  19. Heat release from wood wall assemblies using oxygen consumption method

    Science.gov (United States)

    Hao C. Tran; Robert E. White

    1990-01-01

    The concept of heat release rate is gaining acceptance in the evaluation of fire performance of materials and assemblies. However, this concept has not been incorporated into fire endurance testing such as the ASTM E-119 test method. Heat release rate of assemblies can be useful in determining the time at which the assemblies start to contribute to the controlled fire...

  20. Water hardness and the effects of Cd on oxygen consumption ...

    African Journals Online (AJOL)

    DRINIE

    2004-01-01

    Jan 1, 2004 ... regulatory and acid-base balance disturbances (Goss and Wood,. 1988). An increase in .... tanks, tap water and from a borehole at the farm Rooipoort 29 ..... lethal environmental copper exposure on the energy metabolism of.

  1. [Study of oxygen consumption in infants of diabetic mothers].

    Science.gov (United States)

    Courpotin, C; Keenan, W J; Sutherland, J M; Gerbeaux, J

    1975-01-01

    The energy expenditure (VO2) was measured during the first 36 hours of life in 10 infants of diabetic mothers (IDM) and in 16 normal newborns (NB). The mean VO2 was 5,72 ml/kg/min +/- 0,4 for the NB and 4,94 ml/kg/min. +/- 0,3 for the IDM. The respiratory quotients were similar for both groups. Blood glucose determination from all IDM were greater than 44 mg%. Although the low VO2 for IDM is unexplained, several hypothesis might be anticipated: either lack of utilization of abundant endogenous glycogen stores or increased metabolism of glucose by the cells.

  2. Myocardial oxygen consumption at rest and during submaximal ...

    African Journals Online (AJOL)

    olayemitoyin

    2008-11-26

    Nov 26, 2008 ... ratio were the most important independent parameters in prediction of RPP. The study shows that ... study of various medical, surgical, and physical interventions on .... increase in myocardial activity and thus the MVO2 at rest.

  3. Oxygen sensitization of mammalian cells under different irradiation conditions

    International Nuclear Information System (INIS)

    Ling, C.C.; Michaels, H.B.; Gerweck, L.E.; Epp, E.R.; Peterson, E.C.

    1981-01-01

    The oxygen dependence of the radiosensitivity of cultured CHO cells was examined in detail with particular attention paid to avoiding possible artifacts due to radiolytic oxygen depletion. Two methods of gas equilibration and irradiation were used. In the first approach, cells were irradiated with 50-kVp X rays in a thin-layer geometry which offered maximum interchange between the cells and the surrounding gas. The second technique employed 280-kVp X irradiation of cells under full-medium conditions with mechanical agitation to minimize the effect of radiochemical oxygen consumption by promoting rapid oxygen replenishment. With these techniques oxygen radiosensitization was clearly resolved at an oxygen concentration of 0.03% in the gas phase. The oxygen K curves measured by these two methods were similar in shape over a wide range of oxygen concentration

  4. Aerobic Microbial Respiration In Oceanic Oxygen Minimum Zones

    DEFF Research Database (Denmark)

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

    2015-01-01

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

  5. Artificial oxygen transport protein

    Science.gov (United States)

    Dutton, P. Leslie

    2014-09-30

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

  6. Effects of modified multistage field test on performance and physiological responses in wheelchair basketball players.

    Science.gov (United States)

    Weissland, Thierry; Faupin, Arnaud; Borel, Benoit; Berthoin, Serge; Leprêtre, Pierre-Marie

    2015-01-01

    A bioenergetical analysis of manoeuvrability and agility performance for wheelchair players is inexistent. It was aimed at comparing the physiological responses and performance obtained from the octagon multistage field test (MFT) and the modified condition in "8 form" (MFT-8). Sixteen trained wheelchair basketball players performed both tests in randomized condition. The levels performed (end-test score), peak values of oxygen uptake (VO2peak), minute ventilation (VEpeak), heart rate (HRpeak), peak and relative blood lactate (Δ[Lact(-)] = peak--rest values), and the perceived rating exertion (RPE) were measured. MFT-8 induced higher VO2peak and VEpeak values compared to MFT (VO2peak: 2.5 ± 0.6 versus 2.3 ± 0.6 L · min(-1) and VEpeak: 96.3 ± 29.1 versus 86.6 ± 23.4 L · min(-1); P < 0.05) with no difference in other parameters. Significant relations between VEpeak and end-test score were correlated for both field tests (P < 0.05). At exhaustion, MFT attained incompletely VO2peak and VEpeak. Among experienced wheelchair players, MFT-8 had no effect on test performance but generates higher physiological responses than MFT. It could be explained by demands of wheelchair skills occurring in 8 form during the modified condition.

  7. Arm cranking versus wheelchair propulsion for testing aerobic fitness in children with spina bifida who are wheelchair dependent.

    Science.gov (United States)

    Bloemen, Manon A T; de Groot, Janke F; Backx, Frank J G; Westerveld, Rosalyne A; Takken, Tim

    2015-05-01

    To determine the best test performance and feasibility using a Graded Arm Cranking Test vs a Graded Wheelchair Propulsion Test in young people with spina bifida who use a wheelchair, and to determine the reliability of the best test. Validity and reliability study. Young people with spina bifida who use a wheelchair. Physiological responses were measured during a Graded Arm Cranking Test and a Graded Wheelchair Propulsion Test using a heart rate monitor and calibrated mobile gas analysis system (Cortex Metamax). For validity, peak oxygen uptake (VO2peak) and peak heart rate (HRpeak) were compared using paired t-tests. For reliability, the intra-class correlation coefficients, standard error of measurement, and standard detectable change were calculated. VO2peak and HRpeak were higher during wheelchair propulsion compared with arm cranking (23.1 vs 19.5 ml/kg/min, p = 0.11; 165 vs 150 beats/min, p propulsion showed high intra-class correlation coefficients (ICCs) for both VO2peak (ICC = 0.93) and HRpeak (ICC = 0.90). This pilot study shows higher HRpeak and a tendency to higher VO2peak in young people with spina bifida who are using a wheelchair when tested during wheelchair propulsion compared with arm cranking. Wheelchair propulsion showed good reliability. We recommend performing a wheelchair propulsion test for aerobic fitness testing in this population.

  8. [birthweight And Caffeine Consumption].

    OpenAIRE

    Bicalho, Gladys Gripp; Barros Filho, Antônio de Azevedo

    2015-01-01

    To assess the association between maternal caffeine consumption during pregnancy and low birth weight, prematurity and intrauterine growth retardation. A case-control was carried out and 354 newborns of single labor with birthweight 3,000 g (controls) were analyzed. Caffeine consumption was calculated based on daily consumption of coffee, soft drinks and tea. Results were adjusted using multiple logistic regression for the following confounders: mother's age, schooling, income, marital status...

  9. Alcohol Consumption in Students

    OpenAIRE

    Tran, Cathy

    2010-01-01

    Drinking behaviour among university students is a serious public health concern. Reasons for drinking are complex and many factors contribute to this behaviour. Previous research has established links between personality factors and alcohol consumption and also between metacognitions and alcohol consumption. Few studies have looked into how personality traits and metacognitions interact. This study investigated the relationships between personality, metacognitions and alcohol consumption in a...

  10. Water consumption in Iron Age, Roman, and Early Medieval Croatia.

    Science.gov (United States)

    Lightfoot, E; Slaus, M; O'Connell, T C

    2014-08-01

    Patterns of water consumption by past human populations are rarely considered, yet drinking behavior is socially mediated and access to water sources is often socially controlled. Oxygen isotope analysis of archeological human remains is commonly used to identify migrants in the archeological record, but it can also be used to consider water itself, as this technique documents water consumption rather than migration directly. Here, we report an oxygen isotope study of humans and animals from coastal regions of Croatia in the Iron Age, Roman, and Early Medieval periods. The results show that while faunal values have little diachronic variation, the human data vary through time, and there are wide ranges of values within each period. Our interpretation is that this is not solely a result of mobility, but that human behavior can and did lead to human oxygen isotope ratios that are different from that expected from consumption of local precipitation. © 2014 Wiley Periodicals, Inc.

  11. Oxygen gradients in tissue-engineered PEGT/PBT cartilaginous constructs: Measurement and modeling

    NARCIS (Netherlands)

    Malda, J.; Rouwkema, Jeroen; Martens, D.E.; le Comte, EP; Kooy, F.K.; Tramper, J.; van Blitterswijk, Clemens; Riesle, J.U.

    2004-01-01

    The supply of oxygen within three-dimensional tissue-engineered (TE) cartilage polymer constructs is mainly by diffusion. Oxygen consumption by cells results in gradients in the oxygen concentration. The aims of this study were, firstly, to identify the gradients within TE cartilage polymer

  12. Oxygen gradients in tissue-engineered PEGT/PBT cartilaginous constructs: measurement and modeling

    NARCIS (Netherlands)

    Malda, J.; Rouwkema, J.; Martens, D.E.; Paul le Comte, E.; Kooy, F.K.; Tramper, J.; Blitterswijk, van C.A.; Riesle, J.

    2004-01-01

    The supply of oxygen within three-dimensional tissue-engineered (TE) cartilage polymer constructs is mainly by diffusion. Oxygen consumption by cells results in gradients in the oxygen concentration. The aims of this study were, firstly, to identify the gradients within TE: cartilage polymer

  13. Consumption and the Consumer

    Directory of Open Access Journals (Sweden)

    Maria VADUVA

    2016-09-01

    Full Text Available The consumer is that trader responsible for consumption act of some final goods or services who decided what must be produce and in what cantity, being the one who make the economic mechanism to move. Consumption is in close connection with the production of goods and services, exerting an active role, any activity should be complete by consuming its results; consumption creates the motivation to achieve economic and non-economic activities. The traditional approach to consumer behavior starts from hypothesised that all consumers seek to maximize the aggregate utility obtained of satisfactions resulting from consumption of goods taking into account the budgetary constraints given by income that consumer has and the prices of these goods. In the conditions of modern economy, consumption can be increased by diseconomies. If consumption depends on permanent income, revenue growth effectively does not exert influence on consumption only to the extent that this increase of income leads to increasing permanent income consumer. Consumption is viewed as an active agent of economic life, it is not only a consumer of goods and services but also a producer.

  14. Experience and Sustainable Consumption

    DEFF Research Database (Denmark)

    Rasmussen, Tove Arendt

    consumption may re-enchant ordinary consumption and thereby even become a part of marketing and the experience economy. New layers of meaning are at stake and altruistic motives come into play; doing something good for someone or something, aside from oneself, is a very strong trigger of positive emotions...

  15. Experience and Sustainable Consumption

    DEFF Research Database (Denmark)

    Rasmussen, Tove Arendt

    2014-01-01

    consumption may re-enchant ordinary consumption and thereby even become a part of marketing and the experience economy. New layers of meaning are at stake and altruistic motives come into play; doing something good for someone or something, aside from oneself, is a very strong trigger of positive emotions...

  16. Value Creation and Consumption

    DEFF Research Database (Denmark)

    Taillard, Marie; Voyer, Benjamin; Glaveanu, Vlad Petre

    2014-01-01

    An effect of the digital economy has been to provide consumers with almost unlimited ways to customize their consumption activities. They can craft each consumption experience to fit specific contexts, needs, emotions and other factors. A teenager’s night out is documented and shared with her...

  17. The influence of systemic hemodynamics and oxygen transport on cerebral oxygen saturation in neonates after the Norwood procedure.

    Science.gov (United States)

    Li, Jia; Zhang, Gencheng; Holtby, Helen; Guerguerian, Anne-Marie; Cai, Sally; Humpl, Tilman; Caldarone, Christopher A; Redington, Andrew N; Van Arsdell, Glen S

    2008-01-01

    Ischemic brain injury is an important morbidity in neonates after the Norwood procedure. Its relationship to systemic hemodynamic oxygen transport is poorly understood. Sixteen neonates undergoing the Norwood procedure were studied. Continuous cerebral oxygen saturation was measured by near-infrared spectroscopy. Continuous oxygen consumption was measured by respiratory mass spectrometry. Pulmonary and systemic blood flow, systemic vascular resistance, oxygen delivery, and oxygen extraction ratio were derived with measurements of arterial, and superior vena cava and pulmonary venous gases and pressures at 2- to 4-hour intervals during the first 72 hours in the intensive care unit. Mean cerebral oxygen saturation was 66% +/- 12% before the operation, reduced to 51% +/- 13% on arrival in the intensive care unit, and remained low during the first 8 hours; it increased to 56% +/- 9% at 72 hours, still significantly lower than the preoperative level (P blood flow and oxygen delivery (P blood flow (P = .001) and hemoglobin (P = .02) and negatively correlated with systemic vascular resistance (P = .003). It was not correlated with oxygen consumption (P > .05). Cerebral oxygen saturation decreased significantly in neonates during the early postoperative period after the Norwood procedure and was significantly influenced by systemic hemodynamic and metabolic events. As such, hemodynamic interventions to modify systemic oxygen transport may provide further opportunities to reduce the risk of cerebral ischemia and improve neurodevelopmental outcomes.

  18. Oxygen Consumption Ratio - Reduction in Energy Consumption Using Moving Bed Biofilter

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Land-based reuse systems offer many advantages over netpens or flow-through systems. This includes reduced siting problems, better control of water quality, and...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-02-16

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

  20. Biogeochemistry: Oxygen burrowed away

    NARCIS (Netherlands)

    Meysman, F.J.R.

    2014-01-01

    Multicellular animals probably evolved at the seafloor after a rise in oceanic oxygen levels. Biogeochemical model simulations suggest that as these animals started to rework the seafloor, they triggered a negative feedback that reduced global oxygen.

  1. Oxygen transport membrane

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a novel composite oxygen transport membrane as well as its preparation and uses thereof.......The present invention relates to a novel composite oxygen transport membrane as well as its preparation and uses thereof....

  2. Proterozoic atmospheric oxygen

    DEFF Research Database (Denmark)

    Canfield, Donald Eugene

    2014-01-01

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

  3. Oxygen evolution reaction catalysis

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-09-06

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

  4. Interactive effect of body posture on exercise-induced atrial natriuretic peptide release.

    Science.gov (United States)

    Ray, C A; Delp, M D; Hartle, D K

    1990-05-01

    The purpose of this investigation was to test the hypothesis that supine exercise elicits a greater atrial natriuretic peptide (ANP) response than upright exercise because of higher atrial filling pressure attained in the supine posture. Plasma ANP concentration ([ANP]) was measured during continuous graded supine and upright exercise in eight healthy men at rest after 4 min of cycling exercise at 31, 51, and 79% of posture-specific peak oxygen uptake (VO2 peak), after 2 min of cycling at posture-specific VO2 peak, and 5 and 15 min postexercise. [ANP] was significantly increased (P less than 0.05) above rest by 64, 140, and 228% during supine cycling at 51 and 79% and VO2 peak, respectively. During upright cycling, [ANP] was significantly increased (P less than 0.05) at 79% (60%) and VO2 peak (125%). After 15 min of postexercise rest, [ANP] remained elevated (P less than 0.05) only in the supine subjects. [ANP] was 63, 79, and 75% higher (P less than 0.05) in the supine than in the upright position during cycling at 51 and 79% and VO2 peak. Systolic, diastolic, and mean blood pressures were not significantly (P greater than 0.05) different between positions in all measurement periods. Heart rates were lower (P less than 0.05) in the supine position compared with the upright position. In conclusion, these results suggest that supine exercise elicits greater ANP release independent of blood pressure and heart rate but presumably caused by greater venous return, central blood volume, and concomitant atrial filling pressure and stretch.

  5. Cardiopulmonary fitness correlates with regional cerebral grey matter perfusion and density in men with coronary artery disease.

    Directory of Open Access Journals (Sweden)

    Bradley J MacIntosh

    Full Text Available Physical activity is associated with positive effects on the brain but there is a paucity of clinical neuroimaging data in patients with coronary artery disease (CAD, a cardiovascular condition associated with grey matter loss. The purpose of this study was to determine which brain regions are impacted by cardiopulmonary fitness and with the change in fitness after 6 months of exercise-based cardiac rehabilitation.CAD patients underwent magnetic resonance imaging at baseline, and peak volume of oxygen uptake during exercise testing (VO2Peak was measured at baseline and after 6 months of training. T1-weighted structural images were used to perform grey matter (GM voxel-based morphometry (VBM. Pseudo-continuous arterial spin labeling (pcASL was used to produce cerebral blood flow (CBF images. VBM and CBF data were tested voxel-wise using VO2Peak and age as explanatory variables.In 30 men with CAD (mean age 65±7 years, VBM and CBF identified 7 and 5 respective regions positively associated with baseline VO2Peak. These included the pre- and post-central, paracingulate, caudate, hippocampal regions and converging findings in the putamen. VO2Peak increased by 20% at follow-up in 29 patients (t = 9.6, df = 28, p<0.0001. Baseline CBF in the left post-central gyrus and baseline GM density in the right putamen predicted greater change in VO2Peak.Perfusion and GM density were associated with fitness at baseline and with greater fitness gains with exercise. This study identifies new neurobiological correlates of fitness and demonstrates the utility of multi-modal MRI to evaluate the effects of exercise in CAD patients.

  6. Bat consumption in Thailand

    Directory of Open Access Journals (Sweden)

    Kanokwan Suwannarong

    2016-01-01

    Full Text Available Background: Human consumption of bats poses an increasing public health threat globally. Communities in which bat guano is mined from caves have extensive exposure to bat excreta, often harvest bats for consumption, and are at risk for bat-borne diseases. Methods: This rapid ethnographic study was conducted in four provinces of Thailand (Ratchaburi, Sakaeo, Nakorn Sawan, and Phitsanulok, where bat guano was mined and sold during the period April–August 2014. The aim of this study was to understand behaviors and risk perceptions associated with bat conservation, exposure to bats and their excreta, and bat consumption. Sixty-seven respondents playing various roles in bat guano mining, packaging, sale, and use as fertilizer participated in the study. Data were collected through interviews and/or focus group discussions. Results: In spite of a bat conservation program dating back to the 1980s, the benefits of conserving bats and the risks associated with bat consumption were not clear and infrequently articulated by study respondents. Discussion: Since bat consumption continues, albeit covertly, the risk of bat-borne diseases remains high. There is an opportunity to reduce the risk of bat-borne diseases in guano-mining communities by strengthening bat conservation efforts and raising awareness of the health risks of bat consumption. Further research is suggested to test behavior change strategies for reducing bat consumption.

  7. Bat consumption in Thailand.

    Science.gov (United States)

    Suwannarong, Kanokwan; Schuler, Sidney

    2016-01-01

    Human consumption of bats poses an increasing public health threat globally. Communities in which bat guano is mined from caves have extensive exposure to bat excreta, often harvest bats for consumption, and are at risk for bat-borne diseases. This rapid ethnographic study was conducted in four provinces of Thailand (Ratchaburi, Sakaeo, Nakorn Sawan, and Phitsanulok), where bat guano was mined and sold during the period April-August 2014. The aim of this study was to understand behaviors and risk perceptions associated with bat conservation, exposure to bats and their excreta, and bat consumption. Sixty-seven respondents playing various roles in bat guano mining, packaging, sale, and use as fertilizer participated in the study. Data were collected through interviews and/or focus group discussions. In spite of a bat conservation program dating back to the 1980s, the benefits of conserving bats and the risks associated with bat consumption were not clear and infrequently articulated by study respondents. Since bat consumption continues, albeit covertly, the risk of bat-borne diseases remains high. There is an opportunity to reduce the risk of bat-borne diseases in guano-mining communities by strengthening bat conservation efforts and raising awareness of the health risks of bat consumption. Further research is suggested to test behavior change strategies for reducing bat consumption.

  8. [Domiciliary oxygen therapy].

    Science.gov (United States)

    Abdel Kafi, S

    2010-09-01

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

  9. Aircraft Oxygen Generation

    Science.gov (United States)

    2012-02-01

    An Oxygen Enriched Air System for the AV-8A Harrier (NADC-81198-60).” 70 Horch , T., et. al. “The F-16 Onboard Oxygen Generating System: Performance...Only and Safety Privileged). Horch , T., Miller, R., Bomar, J., Tedor, J., Holden, R., Ikels, K., & Lozano, P. (1983). The F-16 Onboard Oxygen

  10. Marriage and Consumption

    DEFF Research Database (Denmark)

    Blow, Laura; Browning, Martin; Ejrnæs, Mette

    We examine theoretically and empirically consumption over the early part of the life-cycle. The main focus is on the transition from being single to living with someone else. Our theoretical model allows for publicness in consumption; uncertainty concerning marriage; differences between lifetime...... incomes for prospective partners and a marriage premium. We develop a two period model to bring out the main features of the impact of marriage on consumption and saving. We then develop a multi-period model that can be taken to the data on expenditures by singles and couples aged between 18 and 30. Our...

  11. Oxygen configurations in silica

    International Nuclear Information System (INIS)

    Chelikowsky, James R.; Chadi, D. J.; Binggeli, N.

    2000-01-01

    We propose a transition state for oxygen in silica. This state is produced by the insertion of an oxygen molecule into the Si-O-Si bond, i.e., it consists of producing a Si-O-O-O-Si bond. This state allows molecular oxygen diffusion in silica without breaking the molecular O 2 bond and it is energetically more stable than a peroxy configuration. This configuration may allow for exchange of molecular oxygen with the oxygen in the silica framework. (c) 2000 The American Physical Society

  12. Interactive energy consumption visualization

    CSIR Research Space (South Africa)

    Lunga, D

    2014-11-01

    Full Text Available in an office building environment. The main goal is to highlight high consumptions patterns, estimate costs and savings, and recommend energy saving strategies. In its useful nature, the dashboard can provide valuable information for further programs tied...

  13. Emotions and consumption behaviour

    OpenAIRE

    I. Soscia

    2013-01-01

    This stimulating book scrutinizes how emotions function in consumers, from both a psychological and a managerial perspective. It demonstrates how gratitude, happiness, guilt, anger, pride and sadness determine different post-consumption behaviours such as positive and negative word of mouth, repurchase intention and complaint behaviour. The emotional side of consumption seems to play an essential role in explaining choices made and actions taken by consumers. Isabella Soscia explores the ...

  14. Carbon offsetting: sustaining consumption?

    OpenAIRE

    Heather Lovell; Harriet Bulkeley; Diana Liverman

    2009-01-01

    In this paper we examine how theories of sustainable and ethical consumption help us to understand a new, rapidly expanding type of consumer product designed to mitigate climate change: carbon offsets. The voluntary carbon offset market grew by 200% between 2005 and 2006, and there are now over 150 retailers of voluntary carbon offsets worldwide. Our analysis concentrates on the production and consumption of carbon offsets, drawing on ideas from governmentality and political ecology about how...

  15. Changes in cultural consumption

    DEFF Research Database (Denmark)

    Navarrete, T.; Borowiecki, K. J.

    2016-01-01

    Visits to museums have been studied as hedonic and utilitarian forms of cultural consumption, though limited attention has been given to the access of museum collections online. We perform a unique historic analysis of the visibility of collections in a museum of ethnographic collections and comp......, particularly when showing them being used). Results support understanding of online heritage consumption and emerging dynamics, particularly outside of an institutional environment, such as Wikipedia. © 2016 Informa UK Limited, trading as Taylor & Francis Group....

  16. Consumption and Children

    DEFF Research Database (Denmark)

    Browning, Martin; Ejrnæs, Mette

    2009-01-01

    supply. We develop two tests of the extreme hypothesis that only changes in family structure matter. We estimate effects of the numbers and ages of children on consumption. These estimates allow us to rationalize all of the increase in consumption without recourse to any of the causal mechanisms. Our...... estimates can be interpreted either as giving upper bounds on the effects of children or as evidence that the other causes are not important....

  17. Economic theories of sustainable consumption

    NARCIS (Netherlands)

    Ferrer-i-Carbonell, Ada; Bergh, van den Jeroen C.J.M.

    1999-01-01

    The term `sustainable consumption' denotes the search for consumption patterns that reduce human pressure on the environment and nature. This searchinvolves three levels of research. First, the relationship between consumption, lifestyles and environmental sustainability has to be clarified.

  18. Effects of Fiber Type and Size on the Heterogeneity of Oxygen Distribution in Exercising Skeletal Muscle

    Science.gov (United States)

    Liu, Gang; Mac Gabhann, Feilim; Popel, Aleksander S.

    2012-01-01

    The process of oxygen delivery from capillary to muscle fiber is essential for a tissue with variable oxygen demand, such as skeletal muscle. Oxygen distribution in exercising skeletal muscle is regulated by convective oxygen transport in the blood vessels, oxygen diffusion and consumption in the tissue. Spatial heterogeneities in oxygen supply, such as microvascular architecture and hemodynamic variables, had been observed experimentally and their marked effects on oxygen exchange had been confirmed using mathematical models. In this study, we investigate the effects of heterogeneities in oxygen demand on tissue oxygenation distribution using a multiscale oxygen transport model. Muscles are composed of different ratios of the various fiber types. Each fiber type has characteristic values of several parameters, including fiber size, oxygen consumption, myoglobin concentration, and oxygen diffusivity. Using experimentally measured parameters for different fiber types and applying them to the rat extensor digitorum longus muscle, we evaluated the effects of heterogeneous fiber size and fiber type properties on the oxygen distribution profile. Our simulation results suggest a marked increase in spatial heterogeneity of oxygen due to fiber size distribution in a mixed muscle. Our simulations also suggest that the combined effects of fiber type properties, except size, do not contribute significantly to the tissue oxygen spatial heterogeneity. However, the incorporation of the difference in oxygen consumption rates of different fiber types alone causes higher oxygen heterogeneity compared to control cases with uniform fiber properties. In contrast, incorporating variation in other fiber type-specific properties, such as myoglobin concentration, causes little change in spatial tissue oxygenation profiles. PMID:23028531

  19. Reduced oxygen enhancement ratio at low doses

    International Nuclear Information System (INIS)

    Palcic, B.; Skarsgard, L.D.

    1984-01-01

    The oxygen depletion rate in cell suspensions was measured using a Clark electrode. It was found that under experimental conditions used in this laboratory for hypoxic irradiations, the oxygen levels before the start of irradiation are always below 0.1μm, the levels which could give any significant enhancement to radiation inactivation by x-rays. The measured O/sub 2/ depletion rates were comparable to those reported in the literature. Chinese hamster cells (CHO) were made hypoxic by gas exchange, combined with metabolic consumption of oxygen by cells at 37 0 C. Full survival curves were determined in the dose range 0 to 3Gy using the low dose survival assay. The results confirmed the authors' earlier finding that the OER decreases at low doses. The authors therefore believe that the dose-dependent OER is a true radiobiological phenomenon and not an artifact of the experimental method used in the low dose survival assay

  20. Oxygen dynamics and transport in the Mediterranean sponge Aplysina aerophoba

    DEFF Research Database (Denmark)

    Hoffmann, F.; Røy, Hans; Bayer, K.

    2008-01-01

    The Mediterranean sponge Aplysina aerophoba kept in aquaria or cultivation tanks can stop pumping for several hours or even days. To investigate changes in the chemical microenvironments, we measured oxygen profiles over the surface and into the tissue of pumping and non-pumping A. aerophoba...... specimens with Clark-type oxygen microelectrodes (tip diameters 18-30 μm). Total oxygen consumption rates of whole sponges were measured in closed chambers. These rates were used to back-calculate the oxygen distribution in a finite-element model. Combining direct measurements with calculations of diffusive...... flux and modeling revealed that the tissue of non-pumping sponges turns anoxic within 15 min, with the exception of a 1 mm surface layer where oxygen intrudes due to molecular diffusion over the sponge surface. Molecular diffusion is the only transport mechanism for oxygen into non-pumping sponges...

  1. Modeling the oxygen microheterogeneity of tumors for photodynamic therapy dosimetry

    Science.gov (United States)

    Pogue, Brian W.; Paulsen, Keith D.; O'Hara, Julia A.; Hoopes, P. Jack; Swartz, Harold

    2000-03-01

    Photodynamic theory of tumors uses optical excitation of a sensitizing drug within tissue to produce large deposits of singlet oxygen, which are thought to ultimately cause the tumor destruction. Predicting dose deposition of singlet oxygen in vivo is challenging because measurement of this species in vivo is not easily achieved. But it is possible to follow the concentration of oxygen in vivo, and so measuring the oxygen concentration transients during PDT may provide a viable method of estimating the delivered dose of singlet oxygen. However modeling the microscopic heterogeneity of the oxygen distribution within a tumor is non-trivial, and predicting the microscopic dose deposition requires further study, but this study present the framework and initial calibration needed or modeling oxygen transport in complex geometries. Computational modeling with finite elements provides a versatile structure within which oxygen diffusion and consumption can be modeled within realistic tissue geometries. This study develops the basic tools required to simulate a tumor region, and examines the role of (i) oxygen supply and consumption rates, (ii) inter- capillary spacing, (iii) photosensitizer distribution, and (iv) differences between simulated tumors and those derived directly from histology. The result of these calculations indicate that realistic tumor tissue capillary networks can be simulated using the finite element method, without excessive computational burden for 2D regions near 1 mm2, and 3D regions near 0.1mm3. These simulations can provide fundamental information about tissue and ways to implement appropriate oxygen measurements. These calculations suggest that photodynamic therapy produces the majority of singlet oxygen in and near the blood vessels, because these are the sites of highest oxygen tension. These calculations support the concept that tumor vascular regions are the major targets for PDT dose deposition.

  2. Integrated turbomachine oxygen plant

    Science.gov (United States)

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

    2014-06-17

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

  3. Ambient oxygen promotes tumorigenesis.

    Directory of Open Access Journals (Sweden)

    Ho Joong Sung

    2011-05-01

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

  4. Low Temperature Soda-Oxygen Pulping of Bagasse

    OpenAIRE

    Fengxia Yue; Ke-Li Chen; Fachuang Lu

    2016-01-01

    Wood shortages, environmental pollution and high energy consumption remain major obstacles hindering the development of today’s pulp and paper industry. Energy-saving and environmental friendly pulping processes are still needed, especially for non-woody materials. In this study, soda-oxygen pulping of bagasse was investigated and a successful soda-oxygen pulping process for bagasse at 100 °C was established. The pulping parameters of choice were under active alkali charge of 23%, maximum coo...

  5. Ethical Food Consumption

    DEFF Research Database (Denmark)

    Heerwagen, Lennart Ravn

    So-called ‘ethical’ food products have spread across the industrialised world. These are products that are produced under labelling schemes with extraordinary attentiveness to issues such as farm animal welfare and environmental protection. Political decision-makers and other stakeholders in food...... protection. In particular, it aims to examine the concrete improvements that may be pursued through markets for ethical food, and how these improvements are influenced by factors related to individual consumers’ choice of food. This thesis is structured around three research papers that illuminate different...... aspects of ethical food consumption and, based on this, provide concrete policy inputs. The scope of the research is highly interdisciplinary, and includes perspectives from ethics and the social sciences on food consumption. Paper I: Can increased organic consumption mitigate climate changes...

  6. Seafood Consumption and Health

    Directory of Open Access Journals (Sweden)

    Hasan Huseyin Atar

    2009-04-01

    Full Text Available This study discussed relationship between healthy life and seafood consumption. Seafood consumption provide with predicting some chronic diseases, regular diet and a healthy eating habit. Fish and seafood have been promoted as healthy eating by health organizations in many countries all over the world. Seafood includes many important fatty acids, proteins, vitamins and minerals. These have been shown to cause significant biochemical and physiological changes in the body. Especially omega–3 and omega–6 fatty acids have been prevented some major diseases; such as CHD, cancer. [TAF Prev Med Bull 2009; 8(2.000: 173-176

  7. Why Taxing Consumption?

    DEFF Research Database (Denmark)

    Landes, Xavier

    2015-01-01

    Robert Frank is famous for proposing an incremental tax on consumption. His proposition is motivated by the control of positional externalities, i.e. the costs that individuals impose on each other when they consume goods for securing or acquiring social status. A close analysis of Frank...... are controversial while the invocation of efficiency is actually grounded in an underlying view of social cooperation. Secondly, this chapter advances the idea that an ultimate justification for the choice of specific tax base (consumption, income and wealth) expresses such an underlying view. In other words...

  8. Influência das variáveis do treinamento contra-resistência sobre o consumo de oxigênio em excesso após o exercício: uma revisão sistemática Influence of resistance training variables on post-exercise oxygen consumption: a systematic review

    Directory of Open Access Journals (Sweden)

    Antonio Gil Castinheiras Neto

    2009-02-01

    Full Text Available O exercício contra-resistência (ECR pode contribuir para o aumento da taxa metabólica de repouso (TMR. É consenso na literatura que o volume da sessão de ECR pode repercutir em maior gasto calórico e que, após o exercício, o consumo de oxigênio em excesso (EPOC pode variar de acordo com a característica do programa de exercício. Contudo, ainda não é possível definir qual ou quais variáveis de prescrição têm maior impacto sobre o EPOC em sessões de ECR. O objetivo do estudo foi efetuar uma revisão sistemática sobre os estudos que se propuseram a investigar as relações entre o EPOC e variáveis de treinamento em ECR. Os 17 estudos selecionados foram agrupados por similaridade de tratamento (número de séries, intensidade, intervalos de recuperação, velocidade da contração muscular e ordem dos exercícios. Técnicas de estatística descritiva foram utilizadas na tentativa de estabelecer possíveis tendências nas relações dose-resposta. Posteriormente, os dados foram analisados de forma qualitativa. De todas as variáveis analisadas, o curto intervalo de recuperação e o modo de prescrição no formato em circuito foram aquelas com maior impacto provável sobre a magnitude do EPOC. Quanto às demais variáveis, limitações metodológicas não permitem estabelecer tendências, principalmente no tocante à duração do EPOC. Adicionalmente, constata-se a necessidade de padronização de aspectos importantes para a quantificação do EPOC, como o tempo de observação do após o exercício e a forma de aferição da TMR.Resistance training (RT may influence resting metabolic rate (RMR increase. There is a consensus that the volume of the RT session may produce higher caloric expenditure and that the excess post-exercise oxygen consumption (EPOC may vary according to the characteristics of the exercise program. However, it is not possible yet to define which prescription variables have greater impact on the EPOC. The aim

  9. Oxygen dependence of respiration in rat spinotrapezius muscle in situ

    Science.gov (United States)

    Pittman, Roland N.

    2012-01-01

    The oxygen dependence of respiration in striated muscle in situ was studied by measuring the rate of decrease of interstitial Po2 [oxygen disappearance curve (ODC)] following rapid arrest of blood flow by pneumatic tissue compression, which ejected red blood cells from the muscle vessels and made the ODC independent from oxygen bound to hemoglobin. After the contribution of photo-consumption of oxygen by the method was evaluated and accounted for, the corrected ODCs were converted into the Po2 dependence of oxygen consumption, V̇o2, proportional to the rate of Po2 decrease. Fitting equations obtained from a model of heterogeneous intracellular Po2 were applied to recover the parameters describing respiration in muscle fibers, with a predicted sigmoidal shape for the dependence of V̇o2 on Po2. This curve consists of two regions connected by the point for critical Po2 of the cell (i.e., Po2 at the sarcolemma when the center of the cell becomes anoxic). The critical Po2 was below the Po2 for half-maximal respiratory rate (P50) for the cells. In six muscles at rest, the rate of oxygen consumption was 139 ± 6 nl O2/cm3·s and mitochondrial P50 was k = 10.5 ± 0.8 mmHg. The range of Po2 values inside the muscle fibers was found to be 4–5 mmHg at the critical Po2. The oxygen dependence of respiration can be studied in thin muscles under different experimental conditions. In resting muscle, the critical Po2 was substantially lower than the interstitial Po2 of 53 ± 2 mmHg, a finding that indicates that V̇o2 under this circumstance is independent of oxygen supply and is discordant with the conventional hypothesis of metabolic regulation of the oxygen supply to tissue. PMID:22523254

  10. Turkey's net energy consumption

    International Nuclear Information System (INIS)

    Soezen, Adnan; Arcaklioglu, Erol; Oezkaymak, Mehmet

    2005-01-01

    The main goal of this study is to develop the equations for forecasting net energy consumption (NEC) using an artificial neural-network (ANN) technique in order to determine the future level of energy consumption in Turkey. In this study, two different models were used in order to train the neural network. In one of them, population, gross generation, installed capacity and years are used in the input layer of the network (Model 1). Other energy sources are used in input layer of network (Model 2). The net energy consumption is in the output layer for two models. Data from 1975 to 2003 are used for the training. Three years (1981, 1994 and 2003) are used only as test data to confirm this method. The statistical coefficients of multiple determinations (R 2 -value) for training data are equal to 0.99944 and 0.99913 for Models 1 and 2, respectively. Similarly, R 2 values for testing data are equal to 0.997386 and 0.999558 for Models 1 and 2, respectively. According to the results, the net energy consumption using the ANN technique has been predicted with acceptable accuracy. Apart from reducing the whole time required, with the ANN approach, it is possible to find solutions that make energy applications more viable and thus more attractive to potential users. It is also expected that this study will be helpful in developing highly applicable energy policies

  11. Exploring heroin consumption

    NARCIS (Netherlands)

    Trautmann, Franz; Frijns, Tom

    2013-01-01

    In this report we explore some aspects of heroin consumption, using the data we collected through the face-to-face interviews and comparing our findings with data from other research and monitoring sources. We focus on Italy, the Netherlands and England, the three sample Member States where we have

  12. Regional final energy consumptions

    International Nuclear Information System (INIS)

    2011-01-01

    This report comments the differences observed between the French regions and also between these regions and national data in terms of final energy consumption per inhabitant, per GDP unit, and per sector (housing and office building, transport, industry, agriculture). It also comments the evolutions during the last decades, identifies the most recent trends

  13. Bus fuel consumption model

    Energy Technology Data Exchange (ETDEWEB)

    Zargari, S.A. [Iran Univ. of Science and Technology, Teheran (Iran, Islamic Republic of); Khan, A.M. [Carleton Univ., Ottawa, ON (Canada). Dept. of Civil and Environmental Engineering

    2000-07-01

    The interest in rapid bus transit has increased sharply with the realization that modern metropolitan areas rely on public transit to provide for strong economies and communities. As a prevention tool against traffic congestion, deteriorating air quality and rising greenhouse gas emissions, this study of bus fuel consumption was designed to assist in the planning and management of rapid bus transit. The Australian Road Research Board's (ARRB) Road Fuel Consumption Model was used as a starting point. The estimations required were realized with the help of Newtonian Mechanics. The four states of vehicular traffic were examined: acceleration, cruise, deceleration, and idle. The estimated total power required from the engine to overcome resistance forces, to run vehicle accessories and overcome internal engine friction was calculated. The data for the standard and articulated bus was obtained from OC Transpo in Ottawa. The study permitted the authors to conclude that the estimations for the parameters for power requirements and fuel consumption for heavy duty vehicles are appropriate. The methodology for the estimation of fuel consumption on the Transitway, which is part of the rapid bus transit system, proved adequate. In addition, the methodology was useful to estimate fuel savings resulting from demand management strategies with potential for modal shift. 9 refs., 6 tabs.

  14. Sustainable consumption and marketing

    NARCIS (Netherlands)

    Dam, van Y.K.

    2016-01-01

    Sustainable development in global food markets is hindered by the discrepancy between positive consumer attitudes towards sustainable development or sustainability and the lack of corresponding sustainable consumption by a majority of consumers. Apparently for many (light user) consumers the

  15. Consumption growth accounting

    NARCIS (Netherlands)

    Dietzenbacher, Erik; de Groot, Olaf J.; Los, Bart

    The methodology in this paper combines an input-output structural decomposition approach with the supply-side perspective of mainstream growth accounting. In explaining the intertemporal change in consumption per worker, three sets of effects are distinguished. First, contributions due to several

  16. Overview of Alcohol Consumption

    Science.gov (United States)

    ... of Alcohol Consumption Alcohol's Effects on the Body Alcohol Use Disorder Fetal Alcohol Exposure Support & Treatment Alcohol Policy Special ... experience alcohol’s longer-term effects, which can include: Alcohol use disorder Health problems Increased risk for certain cancers In ...

  17. Organic consumption behavior

    NARCIS (Netherlands)

    Du, Shuili; Bartels, Jos; Reinders, Machiel; Sen, Sankar

    2017-01-01

    Consumer demand for organic food and non-food products has been growing dramatically. This study examines organic consumption behavior from a social identification perspective. Focusing on the central role of organic consumer identification (OCI), or the extent to which individuals categorize

  18. The Ideology of Consumption

    DEFF Research Database (Denmark)

    Hansen, Brian Benjamin

    2013-01-01

    This article opts for a return to a critique of the ideology of consumption. Following Slavoj Žižek it argues that what must be addressed in present-day consumer-capitalism is the level of the superego. Superego is not about living up to certain norms/standards; rather, superego fits consumerism...

  19. The Consumption Paradigm in Marketing

    Directory of Open Access Journals (Sweden)

    Eka Ardianto

    2003-08-01

    Full Text Available This article elaborates consumption paradigm in marketing. In background, this paper reviews different perspectives of consumption: economic perspective and marketing perspective. In ontology, this work describes various issues regarding consumption view. In epistemology, this article demonstrates how marketers especially researches explore the consumption phenomena. In methodology, the article describes experiential marketing –one of applied consumption paradigm in marketing, which could be an alternative choice of marketing practices.

  20. Country differences in sustainable consumption

    DEFF Research Database (Denmark)

    Thøgersen, John

    2010-01-01

    In a sustainability perspective, consumption research has an unfortunate individualizing bias, which means that macro and structural causes of unsustainable consumption tend to be ignored. Hence, a comprehensive model of determinants of the sustainability of consumption is developed and applied...... on a specific case: organic food consumption. The analyzed data are published research on why consumer purchase of organic food products differs between countries. As expected, organic food's share of total food consumption depends heavily on political regulation, including legal definitions and standards...

  1. Work-related consumption drivers and consumption at work

    DEFF Research Database (Denmark)

    Røpke, Inge

    2004-01-01

    The main message in this paper is that the discussion on sustainable consumption should also incorporate the consumption that occurs in relation to work and, more generally, the relationship between consumption at work and consumption at home. I start by considering how domestic consumption...... is encouraged by work-related factors and continue to consider how consumption activities occur in the workplace, so illustrating that production and consumption are intertwined. The main part of the paper deals in detail with the conceptual distinction between production and consumption. Inspiration is drawn...... from both ecology and economics with focus on some important predecessors for ecological economics. I conclude with reflections on how to proceed with consumption studies to provide the basis for promoting more sustainable life patterns....

  2. Oxygen enrichment incineration

    International Nuclear Information System (INIS)

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

    2000-10-01

    Oxygen enriched combustion technology has recently been used in waste incineration. To apply the oxygen enrichment on alpha-bearing waste incineration, which is being developed, a state-of-an-art review has been performed. The use of oxygen or oxygen-enriched air instead of air in incineration would result in increase of combustion efficiency and capacity, and reduction of off-gas product. Especially, the off-gas could be reduced below a quarter, which might reduce off-gas treatment facilities, and also increase an efficiency of off-gas treatment. However, the use of oxygen might also lead to local overheating and high nitrogen oxides (NOx) formation. To overcome these problems, an application of low NOx oxy-fuel burner and recycling of a part of off-gas to combustion chamber have been suggested

  3. Oxygen enrichment incineration

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-10-01

    Oxygen enriched combustion technology has recently been used in waste incineration. To apply the oxygen enrichment on alpha-bearing waste incineration, which is being developed, a state-of-an-art review has been performed. The use of oxygen or oxygen-enriched air instead of air in incineration would result in increase of combustion efficiency and capacity, and reduction of off-gas product. Especially, the off-gas could be reduced below a quarter, which might reduce off-gas treatment facilities, and also increase an efficiency of off-gas treatment. However, the use of oxygen might also lead to local overheating and high nitrogen oxides (NOx) formation. To overcome these problems, an application of low NOx oxy-fuel burner and recycling of a part of off-gas to combustion chamber have been suggested.

  4. Hypoxia Tolerance and Metabolic Suppression in Oxygen Minimum Zone Euphausiids: Implications for Ocean Deoxygenation and Biogeochemical Cycles

    KAUST Repository

    Seibel, Brad A.; Schneider, Jillian L.; Kaartvedt, Stein; Wishner, Karen F.; Daly, Kendra L.

    2016-01-01

    respiration experiments. Critical oxygen partial pressures were estimated for each species, and, for E. eximia, measured via oxygen consumption (2.1 kPa, 10 °C, n = 2) and lactate accumulation (1.1 kPa, 10 °C). A primary mechanism facilitating low oxygen

  5. On the mechanisms that limit oxygen uptake during exercise in acute and chronic hypoxia: role of muscle mass

    DEFF Research Database (Denmark)

    Calbet, José A L; Rådegran, Göran; Boushel, Robert

    2009-01-01

    (dye dilution with Cardio-green), leg blood flow (thermodilution), intra-arterial blood pressure and femoral arterial-to-venous differences in blood gases were determined in nine lowlanders studied during incremental exercise using a large (two-legged cycle ergometer exercise: Bike) and a small (one...... altitude acclimatization. Acclimatization improved Bike peak exercise Pa,O2 from 34 +/- 1 in AH to 45 +/- 1 mmHg in CH(P Bike. Acute hypoxia resulted in reduction...... of systemic O2 delivery (46 and 21%) and leg O2 delivery (47 and 26%) during Bike and Knee, respectively, almost matching the corresponding reduction in VO2,peak. Altitude acclimatization restored fully peak systemic and leg O(2) delivery in CH (2.69 +/- 0.27 and 1.28 +/- 0.11 l min(-1), respectively) to sea...

  6. Fuelwood consumption in Newfoundland

    Energy Technology Data Exchange (ETDEWEB)

    1980-01-01

    This study was undertaken to get a first estimate of fuelwood consumption for the island of Newfoundland for the period April 1, 1977 to March 31, 1978. Available literature was reviewed and an assessment made on the existing data collection systems on fuelwood consumption used by the various forestry agencies in the province. A personal interview telephone survey on fuelwood use was conducted for most parts of the Island that had access to wood supplies. Householders were asked how much wood they burned, when they started burning wood, type of wood burning unit used, other sources of heat used, reasons for burning wood, employment, distance travelled to obtain wood, and expected consumption in 1978-79 compared to 1977-78. It was found that the estimated number of households burning wood increased to ca 32,000 in 1977-78. There was a further estimated increase to about 39,500 in 1978-79. In 1977-78, it was estimated that 461,571 stacked cubic metres of fuelwood were consumed on the Island. This was broken down into 318,916 m/sup 3/ of softwood and 142,655 m/sup 3/ of hardwood. Although the statistical methodology used may have led to an overestimate of the volume of wood consumed, the criteria used in the selection of households had the opposite effect in that the volume consumed by a large number of casual wood burners (less than 3 stacked m/sup 3/) was omitted from the estimate. Fuelwood consumption accounted for anywhere from 1% to 77% of the calculated allowable annual cut for the various forest management units on the Island for 1977-78. Overall, fuelwood consumption estimated by the survey accounted for 8% of the estimated allowable annual cut. Use of wood as a fuel is expected to continue increasing and it is recommended that estimates of consumption be periodically updated so that forest management plans can make adequate provision for this demand in future. 5 refs., 16 figs., 7 tabs.

  7. Muscle glycogen reduction in man: relationship between surface EMG activity and oxygen uptake kinetics during heavy exercise.

    Science.gov (United States)

    Osborne, Mark A; Schneider, Donald A

    2006-01-01

    The purpose of this study was to determine whether muscle glycogen reduction prior to exercise would alter muscle fibre recruitment pattern and change either on-transient O2 uptake (VO2) kinetics or the VO2 slow component. Eight recreational cyclists (VO2peak, 55.6 +/- 1.3 ml kg (-1) min(-1)) were studied during 8 min of heavy constant-load cycling performed under control conditions (CON) and under conditions of reduced type I muscle glycogen content (GR). VO2 was measured breath-by-breath for the determination of VO2 kinetics using a double-exponential model with independent time delays. VO2 was higher in the GR trial compared to the CON trial as a result of augmented phase I and II amplitudes, with no difference between trials in the phase II time constant or the magnitude of the slow component. The mean power frequency (MPF) of electromyography activity for the vastus medialis increased over time during both trials, with a greater rate of increase observed in the GR trial compared to the CON trial. The results suggest that the recruitment of additional type II motor units contributed to the slow component in both trials. An increase in fat metabolism and augmented type II motor unit recruitment contributed to the higher VO2 in the GR trial. However, the greater rate of increase in the recruitment of type II motor units in the GR trial may not have been of sufficient magnitude to further elevate the slow component when VO2 was already high and approaching VO2peak .

  8. The role of postural control in the association between aerobic capacity and walking capacity in chronic stroke: a cross-sectional analysis.

    Science.gov (United States)

    Outermans, Jacqueline C; van de Port, Ingrid; Kwakkel, Gert; Visser-Meily, Johanna M; Wittink, Harriet

    2018-03-12

    Reports on the association between aerobic capacity and walking capacity in people after stroke show disparate results. To determine (1) if the predictive validity of peak oxygen uptake (VO2peak) for walking capacity post stroke is different from that of maximal oxygen uptake (VO2max) and (2) if postural control, hemiplegic lower extremity muscle strength, age and gender distort the association between aerobic capacity and walking capacity. Cross-sectional study. General community in Utrecht, the Netherlands. Community-dwelling people more than three months after stroke. Measurement of aerobic capacity were performed with cardiopulmonary exercise testing (CPET) and differentiated between the achievement of VO2peak or VO2max. Measurement of walking capacity with the Six Minute Walk Test (6MWT), postural control with the Performance Oriented Mobility Assessment (POMA) and hemiplegic lower extremity muscle strength with the Motricity Index (MI-LE). Fifty-one out of 62 eligible participants, aged 64.7 (±12.5) years were included. Analysis of covariance (ANCOVA) showed a nonsignificant difference between the predictive validities of VO2max (N = 22, β = 0.56; 95%CI 0.12 - 0.97) and VO2peak (N = 29, β = 0.72; 95%CI 0.38 - 0.92). Multiple regression analysis of the pooled sample showed a significant decrease in the β value of VO2peak (21.6%) for the 6MWT when adding the POMA as a covariate in the association model. VO2peak remained significantly related to 6MWT after correcting for the POMA (β = 0.56 (95%CI 0.39 - 0.75)) CONCLUSIONS: The results suggest similar predictive validity of aerobic capacity for walking capacity in participants achieving VO2max compared to those only achieving VO2peak. Postural control confounds the association between aerobic capacity and walking capacity. Aerobic capacity remains a valid predictor of walking capacity. Aerobic capacity is an important factor associated with walking capacity after stroke. However, to understand this

  9. Videogames, consumption and education

    Directory of Open Access Journals (Sweden)

    Felix ETXEBERRIA VALERDI

    2017-07-01

    Full Text Available The ever-increasing success and use of videogames is a reality in our current society, being 54% of the total consumption of audiovisual or interactive entertainment in Spain in 2007. One of the aspects to be taken into consideration, with respect to the education of children, is the implication for consumption in relation to videogames. The violence portrayed in these games is one of the main topics of debate in the literature about and studies on the effects of videogames on children’s behaviour. However, it is not just a question of protecting minors against the risks of videogames use without control and care exercised by parents or educators. For many years now, despite the risks involved in their use, videogames have been used as another medium in education itself.

  10. Consumption and Needs

    DEFF Research Database (Denmark)

    Læssøe, Jeppe

    1996-01-01

    The contribution takes its point of departure in the relation between the many resource savings initiatives and the lack of interest for the growth in consumption. It argues that what we make up on the roundabouts, we risk to loose on the swings. In order to prevent that it reveals some of the cu...... socio-cultural and life qualitative demands into account. As a conclusion the author outlines some ideals with regard to how to integrate human the dimension in urban ecological design.......The contribution takes its point of departure in the relation between the many resource savings initiatives and the lack of interest for the growth in consumption. It argues that what we make up on the roundabouts, we risk to loose on the swings. In order to prevent that it reveals some...

  11. Sustainable Food Consumption

    DEFF Research Database (Denmark)

    Reisch, Lucia; Eberle, Ulrike; Lorek, Sylvia

    2013-01-01

    Contemporary food production and consumption cannot be regarded as sustainable and raises problems with its wide scope involving diverse actors. Moreover, in the face of demographic change and a growing global population, sus-tainability problems arising from food systems will likely become more...... and globalization of agriculture and food processing, the shift of consumption patterns toward more dietary animal protein, the emergence of modern food styles that entail heavily processed products, the growing gap on a global scale between rich and poor, and the paradoxical lack of food security amid an abundance...... of food. These factors are attributable to national and international policies and regulations, as well as to prevalent business prac-tices and, in particular, consumers' values and habits. The most effective ways for affluent societies to reduce the environmental impact of their diets are to reduce...

  12. Youth and Tourism Consumption

    Directory of Open Access Journals (Sweden)

    Abdolhossein Kalantari

    2008-07-01

    Full Text Available This paper tends to study tourism attitudes among the youth. It argues that in studying tourism among the youth, it is necessary to consider youth’s other behavioral factors in addition to the youth subculture. Therefore, we should study the youth culture from the view point of “Consumption”. In this view, youth tourism is equal to consumption of time, space and signs. Using ongoing theoretical debates and division, we would attempt to explore various factors of youth tourism. This article shows that youth tourism and youth culture are so mutually interconnected that we should comprehend youth tourism based on youth culture and vise versa. In conclusion, analyzing the youth subculture which is rooted in their consumption attitudes, the study attempts to understand youth tourism.

  13. Promoting seafood consumption

    DEFF Research Database (Denmark)

    Scholderer, Joachim; Grunert, Klaus G.

    was that preparing a tasty meal from fresh fish was actually not difficult. In supplemetary materials consumers were provided with recipes for fresh fish. At the same time, major retail chains made MAP-packaged fresh fish filets available in Danish supermarkets. The influence of familiy expectations was harnessed......Before and after the 3-year generic advertising campaign for fresh fish in Denmark, representative consumer samples were surveyed with regard to the attitudes towards fresh fish, perceived family norms, availability of fresh fish in shops, meal preparation skills, intentions to buy fresh fish......, and actual consumption frequencies. In the pre-campaign survey (effective N=641), significant determinants of consumption were availability in shops, meal preparation skills, and intentions to buy fresh fish. The campaign was especially designed to conquer these barriers. The key proposition...

  14. Fuelwood consumption in Newfoundland

    Energy Technology Data Exchange (ETDEWEB)

    1979-01-01

    Fuelwood consumption increased in Newfoundland in the 1970's, but although cutting permits were issued for Crown land, most forests were privately leased and no overall figures were available on the annual cut for domestic use. A personal interview telephone survey was therefore implemented in which householders were questioned on how much wood they burned, when they started burning wood, type of stove and wood used, expected consumption in 1978-79, other sources of heat, employment, and distance travelled to obtain wood. Survey methods and results obtained are presented. Woodburning households increased from about 22,000 before 1973 to about 32,000 in 1977-78 and a further increase to about 39,500 was expected in 1978-79. In 1977-78, 462,571 stacked cubic metres of roundwood were burned on the island. Softwood comprised 69% of this total.

  15. The mediatization of ethical consumption

    DEFF Research Database (Denmark)

    Eskjær, Mikkel Fugl

    2013-01-01

    Over the years, mediatization studies have investigated the influence of media in numerous sections of contemporary society. One area that has received limited attention is the mediatization of consumption, particularly issues concerning ethical consumption. This article presents a study of how...... mediatization is transforming modern consumption and contributing to the mainstreaming of ethical consumption. Based on a study of a Danish online eco-store, the article argues that modern ethical consumption increasingly depends on new media practices to present sustainable consumption as practical...

  16. Sociology of Drug Consumption

    OpenAIRE

    2004-01-01

    In this article which is a review of sociological ideas and studies of drug abusers in social situation, drug addiction steps (particularly alcohol, heroin and cocaine consumption) are revised and some explanations are made. Also, the role of some sociological ideas in drug addiction is considered in which Anomie Theory reads: "because of such duality, the individuals who are not satisfied with their role are in hurt." According to this theory, drug users choose seclusion and neglecting usual...

  17. Ghost crabs on a treadmill: Oxygen Uptake and Haemocyanin ...

    African Journals Online (AJOL)

    Ghost crabs Ocypode ceratophthalmus were exercised on a specially constructed treadmill. At a running speed of 13,3 cm s-1, most crabs ran for 2 h before getting fatigued. At this speed the oxygen consumption rate (MO2) was measured in time intervals for a total of 52 min. For exercised crabs the MO2 values are about ...

  18. A preliminary study

    DEFF Research Database (Denmark)

    Rostgaard Andersen, Thomas; Schmidt, Jakob Friis;