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Sample records for relative vo2 peak

  1. Estimated Prestroke Peak VO2 Is Related to Circulating IGF-1 Levels During Acute Stroke.

    Science.gov (United States)

    Mattlage, Anna E; Rippee, Michael A; Abraham, Michael G; Sandt, Janice; Billinger, Sandra A

    2017-01-01

    Background Insulin-like growth factor-1 (IGF-1) is neuroprotective after stroke and is regulated by insulin-like binding protein-3 (IGFBP-3). In healthy individuals, exercise and improved aerobic fitness (peak oxygen uptake; peak VO 2 ) increases IGF-1 in circulation. Understanding the relationship between estimated prestroke aerobic fitness and IGF-1 and IGFBP-3 after stroke may provide insight into the benefits of exercise and aerobic fitness on stroke recovery. Objective The purpose of this study was to determine the relationship of IGF-1 and IGFBP-3 to estimated prestroke peak VO 2 in individuals with acute stroke. We hypothesized that (1) estimated prestroke peak VO 2 would be related to IGF-1 and IGFBP-3 and (2) individuals with higher than median IGF-1 levels will have higher estimated prestroke peak VO 2 compared to those with lower than median levels. Methods Fifteen individuals with acute stroke had blood sampled within 72 hours of hospital admission. Prestroke peak VO 2 was estimated using a nonexercise prediction equation. IGF-1 and IGFBP-3 levels were quantified using enzyme-linked immunoassay. Results Estimated prestroke peak VO 2 was significantly related to circulating IGF-1 levels (r = .60; P = .02) but not IGFBP-3. Individuals with higher than median IGF-1 (117.9 ng/mL) had significantly better estimated aerobic fitness (32.4 ± 6.9 mL kg -1 min -1 ) than those with lower than median IGF-1 (20.7 ± 7.8 mL kg -1 min -1 ; P = .03). Conclusions Improving aerobic fitness prior to stroke may be beneficial by increasing baseline IGF-1 levels. These results set the groundwork for future clinical trials to determine whether high IGF-1 and aerobic fitness are beneficial to stroke recovery by providing neuroprotection and improving function. © The Author(s) 2016.

  2. 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...

  3. 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%....

  4. 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

  5. Prognostic impact of peakVO2-changes in stable CHF on chronic beta-blocker treatment.

    Science.gov (United States)

    Frankenstein, L; Nelles, M; Hallerbach, M; Dukic, D; Fluegel, A; Schellberg, D; Katus, H A; Remppis, A; Zugck, C

    2007-11-15

    Peak oxygen uptake (pVO2) is used for risk stratification in chronic heart failure (CHF), but little is known about the prognostic impact of pVO2-changes in patients on chronic beta-blocker (BBL) therapy. We therefore prospectively evaluated individual pVO2-changes at a 6-month interval in patients all receiving BBL. 194 patients with stable CHF on stable medication were included (V1) and underwent clinical evaluation and exercise testing. Testing was repeated (V2) at 5.7+/-1.5 months after V1 and patients were followed >12 months after V2. Death or hospitalisation due to cardiac reasons was the predefined EP (EPP, end-point positive; n=62; EPN, end-point negative; n=113). Initial characteristics did not differ between EPP and EPN. Multivariate cox regression analysis revealed that change of pVO2 (EPP: -0.6+/-2.6 ml/kg min; EPN: +2.5+/-3.3 ml/kg min; p<0.001) was independent to pVO2, LVEF, NTproBNP and NYHA at V2 for prediction of the combined end-point during follow-up. An increase of pVO2 by 10% was identified as an adequate cut-off value for risk stratification and ROC-analysis showed the significant incremental prognostic value of the determination of pVO2 changes in combination with pVO2. Serial measurements of pVO2 yield additional information for risk stratification in clinically homogenous CHF patients receiving BBL. This is the first study demonstrating this fact within a narrow predefined interval with all patients on BBL.

  6. Effects of prior heavy exercise on VO(2) kinetics during heavy exercise are related to changes in muscle activity.

    Science.gov (United States)

    Burnley, Mark; Doust, Jonathan H; Ball, Derek; Jones, Andrew M

    2002-07-01

    We hypothesized that the elevated primary O(2) uptake (VO(2)) amplitude during the second of two bouts of heavy cycle exercise would be accompanied by an increase in the integrated electromyogram (iEMG) measured from three leg muscles (gluteus maximus, vastus lateralis, and vastus medialis). Eight healthy men performed two 6-min bouts of heavy leg cycling (at 70% of the difference between the lactate threshold and peak VO(2)) separated by 12 min of recovery. The iEMG was measured throughout each exercise bout. The amplitude of the primary VO(2) response was increased after prior heavy leg exercise (from mean +/- SE 2.11 +/- 0.12 to 2.44 +/- 0.10 l/min, P exercise (491 +/- 108 vs. 604 +/- 151% increase above baseline values, P exercise is related to a greater recruitment of motor units at the onset of exercise.

  7. Low-intensity training increases peak arm VO2 by enhancing both convective and diffusive O2 delivery

    DEFF Research Database (Denmark)

    Boushel, R; Ara, I; Gnaiger, E

    2014-01-01

    in prolonged low-intensity training of a small muscle group when the cardiac output capacity is not directly limiting. The purpose of this study was to investigate the relative roles of circulatory and muscle metabolic mechanisms by which prolonged low-intensity exercise training alters regional muscle VO2 ....

  8. 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.

  9. 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...

  10. 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.

  11. 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.

  12. Initial Weekly HRV Response is Related to the Prospective Change in VO2max in Female Soccer Players.

    Science.gov (United States)

    Esco, M R; Flatt, A A; Nakamura, F Y

    2016-06-01

    The aim of this study was to determine whether the early response in weekly measures of HRV, when derived from a smartphone application, were related to the eventual change in VO2max following an off-season training program in female soccer athletes. 9 female collegiate soccer players participated in an 11-week off-season conditioning program. In the week immediately before and after the training program, each participant performed a test on a treadmill to determine maximal oxygen consumption (VO2max). Daily measures of the log-transformed root mean square of successive R-R intervals (lnRMSSD) were performed by the participants throughout week 1 and week 3 of the conditioning program. The mean and coefficient of variation (CV) lnRMSSD values of week 1 showed small (r=- 0.13, p=0.74) and moderate (r=0.57, p=0.11), respectively, non-significant correlations to the change in VO2max at the end of the conditioning program (∆VO2max). Significant and near-perfect correlation was found between the change in the weekly mean lnRMSSD values from weeks 1 and 3 (∆lnRMSSDM) and ∆VO2max (r=0.90, p=0.002). The current results have identified that the initial change in weekly mean lnRMSSD from weeks 1 to 3 of a conditioning protocol was strongly associated with the eventual adaptation of VO2max. © Georg Thieme Verlag KG Stuttgart · New York.

  13. 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...

  14. Health-Related Physical Fitness in Healthy Untrained Men: Effects on VO2max, Jump Performance and Flexibility of Soccer and Moderate-Intensity Continuous Running

    Science.gov (United States)

    Milanović, Zoran; Pantelić, Saša; Sporiš, Goran; Mohr, Magni; Krustrup, Peter

    2015-01-01

    The purpose of this study was to determine the effects of recreational soccer (SOC) compared to moderate-intensity continuous running (RUN) on all health-related physical fitness components in healthy untrained men. Sixty-nine participants were recruited and randomly assigned to one of three groups, of which sixty-four completed the study: a soccer training group (SOC; n = 20, 34±4 (means±SD) years, 78.1±8.3 kg, 179±4 cm); a running group (RUN; n = 21, 32±4 years, 78.0±5.5 kg, 179±7 cm); or a passive control group (CON; n = 23, 30±3 years, 76.6±12.0 kg, 178±8 cm). The training intervention lasted 12 weeks and consisted of three 60-min sessions per week. All participants were tested for each of the following physical fitness components: maximal aerobic power, minute ventilation, maximal heart rate, squat jump (SJ), countermovement jump with arm swing (CMJ), sit-and-reach flexibility, and body composition. Over the 12 weeks, VO2max relative to body weight increased more (psoccer training and moderate-intensity running, partly due to large decreases in body mass. Additionally soccer training induced pronounced positive effects on jump performance and flexibility, making soccer an effective broad-spectrum fitness training intervention. PMID:26305880

  15. Supercapacitors based on two dimensional VO2 nanosheet electrodes in organic gel electrolyte

    KAUST Repository

    Baby, Rakhi Raghavan; Nagaraju, Doddahalli H.; Beaujuge, Pierre; Alshareef, Husam N.

    2016-01-01

    VO2 is a low band-gap semiconductor with relatively high conductivity among transition metal oxides, which makes it an interesting material for supercapacitor electrode applications. The performance of VO2 as supercapacitor electrode in organic

  16. VO2(B conversion to VO2(A and VO2(M and their oxidation resistance and optical switching properties

    Directory of Open Access Journals (Sweden)

    Zhang Yifu

    2016-03-01

    Full Text Available Vanadium dioxide VO2 has been paid in recent years increasing attention because of its various applications, however, its oxidation resistance properties in air atmosphere have rarely been reported. Herein, VO2(B nanobelts were transformed into VO2(A and VO2(M nanobelts by hydrothermal route and calcination treatment, respectively. Then, we comparatively studied the oxidation resistance properties of VO2(B, VO2(A and VO2(M nanobelts in air atmosphere by thermo-gravimetric analysis and differential thermal analysis (TGA/DTA. It was found that the nanobelts had good thermal stability and oxidation resistance below 341 °C, 408 °C and 465 °C in air, respectively, indicating that they were stable in air at room temperature. The fierce oxidation of the nanobelts occurred at 426, 507 and 645 °C, respectively. The results showed that the VO2(M nanobelts had the best thermal stability and oxidation resistance among the others. Furthermore, the phase transition temperatures and optical switching properties of VO2(A and VO2(M were studied by differential scanning calorimetry (DSC and variable temperature infrared spectra. It was found that the VO2(A and VO2(M nanobelts had outstanding thermochromic character and optical switching properties.

  17. 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...

  18. Time limit and time at VO2max' during a continuous and an intermittent run.

    Science.gov (United States)

    Demarie, S; Koralsztein, J P; Billat, V

    2000-06-01

    The purpose of this study was to verify, by track field tests, whether sub-elite runners (n=15) could (i) reach their VO2max while running at v50%delta, i.e. midway between the speed associated with lactate threshold (vLAT) and that associated with maximal aerobic power (vVO2max), and (ii) if an intermittent exercise provokes a maximal and/or supra maximal oxygen consumption longer than a continuous one. Within three days, subjects underwent a multistage incremental test during which their vVO2max and vLAT were determined; they then performed two additional testing sessions, where continuous and intermittent running exercises at v50%delta were performed up to exhaustion. Subject's gas exchange and heart rate were continuously recorded by means of a telemetric apparatus. Blood samples were taken from fingertip and analysed for blood lactate concentration. In the continuous and the intermittent tests peak VO2 exceeded VO2max values, as determined during the incremental test. However in the intermittent exercise, peak VO2, time to exhaustion and time at VO2max reached significantly higher values, while blood lactate accumulation showed significantly lower values than in the continuous one. The v50%delta is sufficient to stimulate VO2max in both intermittent and continuous running. The intermittent exercise results better than the continuous one in increasing maximal aerobic power, allowing longer time at VO2max and obtaining higher peak VO2 with lower lactate accumulation.

  19. Progressive recruitment of muscle fibers is not necessary for the slow component of VO2 kinetics.

    Science.gov (United States)

    Zoladz, Jerzy A; Gladden, L Bruce; Hogan, Michael C; Nieckarz, Zenon; Grassi, Bruno

    2008-08-01

    The "slow component" of O2 uptake (VO2) kinetics during constant-load heavy-intensity exercise is traditionally thought to derive from a progressive recruitment of muscle fibers. In this study, which represents a reanalysis of data taken from a previous study by our group (Grassi B, Hogan MC, Greenhaff PL, Hamann JJ, Kelley KM, Aschenbach WG, Constantin-Teodosiu D, Gladden LB. J Physiol 538: 195-207, 2002) we evaluated the presence of a slow component-like response in the isolated dog gastrocnemius in situ (n=6) during 4 min of contractions at approximately 60-70% of peak VO2. In this preparation all muscle fibers are maximally activated by electrical stimulation from the beginning of the contraction period, and no progressive recruitment of fibers is possible. Muscle VO2 was calculated as blood flow multiplied by arteriovenous O2 content difference. The muscle fatigued (force decreased by approximately 20-25%) during contractions. Kinetics of adjustment were evaluated for 1) VO2, uncorrected for force development; 2) VO2 normalized for peak force; 3) VO2 normalized for force-time integral. A slow component-like response, described in only one muscle out of six when uncorrected VO2 was considered, was observed in all muscles when VO2/peak force and VO2/force-time were considered. The amplitude of the slow component-like response, expressed as a fraction of the total response, was higher for VO2/peak force (0.18+/-0.06, means+/-SE) and for VO2/force-time (0.22+/-0.05) compared with uncorrected VO2 (0.04+/-0.04). A progressive recruitment of muscle fibers may not be necessary for the development of the slow component of VO2 kinetics, which may be caused by the metabolic factors that induce muscle fatigue and, as a consequence, reduce the efficiency of muscle contractions.

  20. Selective formation of VO2(A) or VO2(R) polymorph by controlling the hydrothermal pressure

    International Nuclear Information System (INIS)

    Ji Shidong; Zhang Feng; Jin Ping

    2011-01-01

    Missing VO 2 (A) usually occurs during the preparation of VO 2 polymorphs. This leads to an ambiguous understanding of the transformation between VO 2 polymorphs. The calculation of the ground state energies for different VO 2 polymorphs indicated that there is only a small energy gap between VO 2 (A) and VO 2 (R), which destined that the transformation from VO 2 (A) to VO 2 (R) should be pressure sensitive. This hypothesis was verified during the synthesizing of VO 2 polymorphs by reducing V 2 O 5 with oxalic acid through hydrothermal treatment process. Selective formation of pure phase VO 2 (A) or VO 2 (R) was achieved by controlling the hydrothermal pressure through varying the filling ratio at 270 deg. C. It was found that a filling ratio over 0.5 favors the formation of pure VO 2 (R) while a reduced filling ratio to 0.4 or lower results in the formation of VO 2 (A). Based on our experiments, VO 2 (B) nanobelts were always first formed and then it transformed to VO 2 (A) by assembling process at increased temperature or extended reaction time. Under further higher pressure, the VO 2 (A) transformed spontaneously to VO 2 (R) initialized from the volume shrinkage due to the formation of denser VO 2 (R). - Graphical abstract: Selective formation of VO 2 (A) or VO 2 (R) could be achieved by controlling the system pressure through varying the filling ratio during hydrothermal treatment. Highlights: → Selective formation of VO 2 polymorphs by controlling hydrothermal pressure. → Ground state energy characteristics were revealed for the first time. → Phase transformation mechanism was clearly elucidated.

  1. Effect of blood haemoglobin concentration on V(O2,max) and cardiovascular function in lowlanders acclimatised to 5260 m

    DEFF Research Database (Denmark)

    Calbet, J A L; Rådegran, G; Boushel, Robert Christopher

    2002-01-01

    not alter peak CO. However, LBF and vascular conductance are higher at altitude when [Hb] is lowered to sea level values, with both relating closely to catecholamine and potassium concentrations. This suggests that the lack of effect of [Hb] on V(O(2),max) may involve reciprocal changes in LBF via local...

  2. 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.

  3. Multiple variables explain the variability in the decrement in VO2max during acute hypobaric hypoxia.

    Science.gov (United States)

    Robergs, R A; Quintana, R; Parker, D L; Frankel, C C

    1998-06-01

    We used multiple regression analyses to determine the relationships between the decrement in sea level (SL, 760 Torr) VO2max during hypobaric hypoxia (HH) and variables that could alter or be related to the decrement in VO2max. HH conditions consisted of 682 Torr, 632 Torr, and 566 Torr, and the measured independent variables were SL-VO2max, SL lactate threshold (SL-LT), the change in hemoglobin saturation at VO2max between 760 and 566 Torr (delta SaO2max), lean body mass (LBM), and gender. Male (N = 14) and female (N = 14) subjects of varied fitness, training status, and residential altitude (1,640-2,460 m) completed cycle ergometry tests of VO2max at each HH condition under randomized and single-blinded conditions. VO2max decreased significantly from 760 Torr after 682 Torr (approximately 915 m) (3.5 +/- 0.9 to 3.4 +/- 0.8 L.min-1, P = 0.0003). Across all HH conditions, the slope of the relative decrement in VO2max (%VO2max) during HH was -9.2%/100 mm Hg (-8.1%/1000 m) with an initial decrease from 100% estimated to occur below 705 Torr (610 m). Step-wise multiple regression revealed that SL-VO2max, SL-LT, delta SaO2max, LBM, and gender each significantly combined to account for 89.03% of the variance in the decrement in VO2max (760-566 Torr) (P decrement in VO2max during HH. The unique variance explanation afforded by SL-LT, LBM, and gender suggests that issues pertaining to oxygen diffusion within skeletal muscle may add to the explanation of between subjects variability in the decrement in VO2max during HH.

  4. Eu-emission quenching by electron screening in VO2 thin films

    International Nuclear Information System (INIS)

    Liu, H.; Lysenko, S.; Rua, A.; Vikhnin, V.; Vasquez, O.; Fernandez, F.E.

    2006-01-01

    As a kind of phase transition functional material, Vanadium dioxide (VO 2 ) thin films deposited on fused quartz substrate were fabricated using pulsed laser deposition (PLD) technique. Europium was introduced for structure study. By laser excitation at 526 nm, VO 2 thin film undergoes a reversible and ultrafast phase transition from semiconductor to metallic state, which results in a change of optical properties. In fluorescence measurement, Eu emission was found severely quenched in all as-grown thin films. After annealing the sample in air, a red Eu-emission appeared. The emission spectrum is characterized by a pronounced twin peak, centered at 617 nm ( 5 D - 7 F 2 ), surrounded by a set of broad, but relatively weaker bands (emission from 5 D to 7 F j manifold). The emission lifetime increased when the sample annealed at higher temperature for longer time. Each spectral component is actually a doublet which is the spectral overlap of emissions from Eu 3+ situated in two sites with different configurations. One is a linear h-Eu 3+ -h, where h stands for holes. Another is a right-angle configuration of h-Eu 3+ -h with Eu 3+ in the corner. In as-grown VO 2 film, Eu 3+ ions can either substitute V 4+ , leaving a negative charge around (Eu 3+ -O) - , or substitute V 5+ , leaving two negative charges around (Eu 3+ -O) -- . Due to trapped electrons in a large radius state, it covers Eu 3+ V 4+ -V 5+ complexes. It suggests that the screening by degenerate electronic gas may result in switching off the Eu-related optical response for a wide spectral region, causing emission quenching in VO 2 films

  5. Validation of a ramp running protocol for determination of the true VO2max in mice

    Directory of Open Access Journals (Sweden)

    Mohamed Ayachi

    2016-08-01

    Full Text Available In the field of comparative physiology, it remains to be established whether the concept of VO2max is valid in the mouse and, if so, how this value can be accurately determined. In humans, VO2max is generally considered to correspond to the plateau observed when VO2 no longer rises with an increase in workload. In contrast, the concept of VO2peak tends to be used in murine studies. The objectives of the present study were to determine whether (i a continuous ramp protocol yielded a higher VO2peak than a stepwise, incremental protocol, and (ii the VO2peak measured in the ramp protocol corresponded to VO2max. The three protocols (based on intensity-controlled treadmill running until exhaustion with eight female FVB/N mice were performed in random order: (a an incremental protocol that begins at 10 m.min-1 speed and increases by 3 m.min-1 every 3 min. (b a ramp protocol with slow acceleration (3 m.min-2, and (c a ramp protocol with fast acceleration (12 m.min-2. Each protocol was performed with two slopes (0° and 25°. Hence, each mouse performed six exercise tests. We found that the value of VO2peak was protocol-dependent (p 8 mmol.l-1 and a respiratory exchange ratio >1. The total duration of the 3 m.min-2 0° ramp protocol was shorter than that of the incremental protocol. Taken as a whole, our results suggest that VO2max in the mouse is best determined by applying a ramp exercise protocol with slow acceleration and no treadmill slope.

  6. 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....

  7. Time limit and VO2 slow component at intensities corresponding to VO2max in swimmers.

    Science.gov (United States)

    Fernandes, R J; Cardoso, C S; Soares, S M; Ascensão, A; Colaço, P J; Vilas-Boas, J P

    2003-11-01

    The purpose of this study was to measure, in swimming pool conditions and with high level swimmers, the time to exhaustion at the minimum velocity that elicits maximal oxygen consumption (TLim at vVO(2)max), and the corresponding VO(2) slow component (O(2)SC). The vVO(2)max was determined through an intermittent incremental test (n = 15). Forty-eight hours later, TLim was assessed using an all-out swim at vVO(2)max until exhaustion. VO(2) was measured through direct oximetry and the swimming velocity was controlled using a visual light-pacer. Blood lactate concentrations and heart rate values were also measured. Mean VO(2)max for the incremental test was 5.09 +/- 0.53 l/min and the corresponding vVO(2)max was 1.46 +/- 0.06 m/s. Mean TLim value was 260.20 +/- 60.73 s and it was inversely correlated with the velocity of anaerobic threshold (r = -0.54, p energy cost of the respiratory muscles (r = 0.51), for p swimming pool, in high level swimmers performing at vVO(2)max, and that higher TLim seems to correspond to higher expected O(2)SC amplitude. These findings seem to bring new data with application in middle distance swimming.

  8. 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.

  9. Electrochemical catalytic activity of tungsten trioxide- modified graphite felt toward VO2+/VO2+ redox reaction

    International Nuclear Information System (INIS)

    Shen, Yang; Xu, Hongfeng; Xu, Pengcheng; Wu, Xiaoxin; Dong, Yiming; Lu, Lu

    2014-01-01

    A novel graphite felt electrode modified with tungsten trioxide (WO 3 ) was developed to improve the electrochemical performance of graphite felt toward the VO 2 + /VO 2+ redox pair. WO 3 was prepared using a hydrothermal method, and the morphology of WO 3 structures was investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The electrochemical property of WO 3 -modified graphite felt toward VO 2 + /VO 2+ was carefully characterized using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements. The hydrogen-vanadium redox flow battery (H-VRFB) test indicates that single cells using 1.1 mg cm −2 WO 3 -modified graphite felt exhibited excellent performance at 70 mA cm −2 , and the corresponding coulombic, voltage, and energy efficiencies were 99.1%, 88.66% and 87.86%, respectively

  10. New Methods for Processing and Quantifying VO2 Kinetics to Steady State: VO2 Onset Kinetics

    Directory of Open Access Journals (Sweden)

    Craig R. McNulty

    2017-09-01

    Full Text Available Current methods of oxygen uptake (VO2 kinetics data handling may be too simplistic for the complex physiology involved in the underlying physiological processes. Therefore, the aim of this study was to quantify the VO2 kinetics to steady state across the full range of sub-ventilatory threshold work rates, with a particular focus on the VO2 onset kinetics. Ten healthy, moderately trained males participated in five bouts of cycling. Each bout involved 10 min at a percentage of the subject's ventilation threshold (30, 45, 60, 75, 90% from unloaded cycling. The VO2 kinetics was quantified using the conventional mono-exponential time constant (tau, τ, as well as the new methods for VO2 onset kinetics. Compared to linear modeling, non-linear modeling caused a deterioration of goodness of fit (main effect, p < 0.001 across all exercise intensities. Remainder kinetics were also improved using a modified application of the mono-exponential model (main effect, p < 0.001. Interestingly, the slope from the linear regression of the onset kinetics data is similar across all subjects and absolute exercise intensities, and thereby independent of subject fitness and τ. This could indicate that there are no functional limitations between subjects during this onset phase, with limitations occurring for the latter transition to steady state. Finally, the continuing use of mono-exponential modeling could mask important underlying physiology of more instantaneous VO2 responses to steady state. Consequently, further research should be conducted on this new approach to VO2 onset kinetics.

  11. Positron annihilation in single crystals of TiO2, VO2, Pb, and U

    International Nuclear Information System (INIS)

    Blau, M.

    1982-09-01

    Two positron annihilation set-ups for Doppler broadening correlation measurements are described. The Doppler broadening spectra were measured in different directions of single crystals of TiO 2 and VO 2 , at room temperature. The anisotropy was explained using two models in which the positron behaves as a free or bounded particle, and was related to the effective charge on the oxygen ion. The changes in the spectra in VO 2 , on passing from the insulator to the metal phase, were found to be gradual and small. The results indicate that the main contribution to the metal-insulator transition is due to changes in the relative occupation of the oxygen p-states and not to changes in covalency or screening. Angular correlations were measured in single crystals of lead in three crystallographic directions. The derivatives of the spectra were compared with the Fermi surface obtained from dHvA measurements, using plane-wave electrons. Most of the features of the experimental derivatives were explained with this simple model. Angular correlation measurements were made on single crystals of uranium in two crystallographic directions. The derivates of the spectra were very wide with a few peaks. (Author)

  12. Electrocatalytic activity of cobalt phosphide-modified graphite felt toward VO2+/VO2+ redox reaction

    Science.gov (United States)

    Ge, Zhijun; Wang, Ling; He, Zhangxing; Li, Yuehua; Jiang, Yingqiao; Meng, Wei; Dai, Lei

    2018-04-01

    A novel strategy for improving the electro-catalytic properties of graphite felt (GF) electrode in vanadium redox flow battery (VRFB) is designed by depositing cobalt phosphide (CoP) onto GF surface. The CoP powder is synthesized by direct carbonization of Co-based zeolitic imidazolate framework (ZIF-67) followed by phosphidation. Cyclic voltammetry results confirm that the CoP-modified graphite felt (GF-CoP) electrode has excellent reversibility and electro-catalytic activity to the VO2+/VO2+ cathodic reaction compared with the pristine GF electrode. The cell using GF-CoP electrode shows apparently higher discharge capacity over that based on GF electrode. The cell using GF-CoP electrode has the capacity of 67.2 mA h at 100 mA cm-2, 32.7 mA h larger than that using GF electrode. Compared with cell using GF electrode, the voltage efficiency of the cell based on GF-CoP electrode increases by 5.9% and energy efficiency by 5.4% at a current density of 100 mA cm-2. The cell using GF-CoP electrode can reach 94.31% capacity retention after 50 cycles at a current density of 30 mA cm-2. The results show that the CoP can effectively promote the VO2+/VO2+ redox reaction, implying that metal phosphides are a new kind of potential catalytic materials for VRFB.

  13. 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.

  14. Ab Initio Metadynamics Study of the VO2+/VO2+ Redox Reaction Mechanism at the Graphite Edge/Water Interface.

    Science.gov (United States)

    Jiang, Zhen; Klyukin, Konstantin; Alexandrov, Vitaly

    2018-06-08

    Redox flow batteries (RFBs) are promising electrochemical energy storage systems, for which development is impeded by a poor understanding of redox reactions occurring at electrode/electrolyte interfaces. Even for the conventional all-vanadium RFB chemistry employing V 2+ /V 3+ and VO 2 + /VO 2+ couples, there is still no consensus about the reaction mechanism, electrode active sites, and rate-determining step. Herein, we perform Car-Parrinello molecular dynamics-based metadynamics simulations to unravel the mechanism of the VO 2 + /VO 2+ redox reaction in water at the oxygen-functionalized graphite (112̅0) edge surface serving as a representative carbon-based electrode. Our results suggest that during the battery discharge aqueous VO 2 + /VO 2+ species adsorb at the surface C-O groups as inner-sphere complexes, exhibiting faster adsorption/desorption kinetics than V 2+ /V 3+ , at least at low vanadium concentrations considered in our study. We find that this is because (i) VO 2 + /VO 2+ conversion does not involve the slow transfer of an oxygen atom, (ii) protonation of VO 2 + is spontaneous and coupled to interfacial electron transfer in acidic conditions to enable VO 2+ formation, and (iii) V 3+ found to be strongly bound to oxygen groups of the graphite surface features unfavorable desorption kinetics. In contrast, the reverse process taking place upon charging is expected to be more sluggish for the VO 2 + /VO 2+ redox couple because of both unfavorable deprotonation of the VO 2+ water ligands and adsorption/desorption kinetics.

  15. Associations between VO2max and vitality in older workers: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    van der Beek Allard J

    2010-11-01

    Full Text Available Abstract Background To prevent early exit from work, it is important to study which factors contribute to healthy ageing. One concept that is assumed to be closely related to, and therefore may influence healthy ageing, is vitality. Vitality consists of both a mental and a physical component, and is characterised by a perceived high energy level, decreased feelings of fatigue, and feeling fit. Since VO2max gives an indication of one's aerobic fitness, which can be improved by increased levels of physical activity, and because feeling fit is one of the main characteristics of vitality, it is hypothesised that VO2max is related to vitality. Therefore, the aim of this study was to investigate the associations between VO2max and vitality. Methods In 427 older workers (aged 45 + years participating in the Vital@Work study, VO2max was estimated at baseline using the 2-km UKK walk test. Vitality was measured by both the UWES Vitality Scale and the RAND-36 Vitality Scale. Associations were analysed using linear regression analyses. Results The linear regression models, adjusted for age, showed a significant association between VO2max and vitality measured with the RAND-36 Vitality Scale (β = 0.446; 95% CI: 0.220-0.673. There was no significant association between VO2max and vitality measured with the UWES (β = -0.006; 95% CI:-0.017 - 0.006, after adjusting for age, gender and chronic disease status. Conclusions VO2max was associated with a general measure of vitality (measured with the RAND-36 Vitality Scale, but not with occupational health related vitality (measured with the UWES Vitality Scale. The idea that physical exercise can be used as an effective tool for improving vitality was supported in this study. Trial registration NTR1240

  16. Associations between VO2max and vitality in older workers: a cross-sectional study.

    Science.gov (United States)

    Strijk, Jorien E; Proper, Karin I; Klaver, Linda; van der Beek, Allard J; van Mechelen, Willem

    2010-11-09

    To prevent early exit from work, it is important to study which factors contribute to healthy ageing. One concept that is assumed to be closely related to, and therefore may influence healthy ageing, is vitality. Vitality consists of both a mental and a physical component, and is characterised by a perceived high energy level, decreased feelings of fatigue, and feeling fit. Since VO2max gives an indication of one's aerobic fitness, which can be improved by increased levels of physical activity, and because feeling fit is one of the main characteristics of vitality, it is hypothesised that VO2max is related to vitality. Therefore, the aim of this study was to investigate the associations between VO2max and vitality. In 427 older workers (aged 45 + years) participating in the Vital@Work study, VO2max was estimated at baseline using the 2-km UKK walk test. Vitality was measured by both the UWES Vitality Scale and the RAND-36 Vitality Scale. Associations were analysed using linear regression analyses. The linear regression models, adjusted for age, showed a significant association between VO2max and vitality measured with the RAND-36 Vitality Scale (β = 0.446; 95% CI: 0.220-0.673). There was no significant association between VO2max and vitality measured with the UWES (β = -0.006; 95% CI:-0.017 - 0.006), after adjusting for age, gender and chronic disease status. VO2max was associated with a general measure of vitality (measured with the RAND-36 Vitality Scale), but not with occupational health related vitality (measured with the UWES Vitality Scale). The idea that physical exercise can be used as an effective tool for improving vitality was supported in this study. NTR1240.

  17. Observation of reduced phase transition temperature in N-doped thermochromic film of monoclinic VO_2

    International Nuclear Information System (INIS)

    Wan, Meinan; Xiong, Mo; Li, Neng; Liu, Baoshun; Wang, Shuo; Ching, Wai-Yim; Zhao, Xiujian

    2017-01-01

    Highlights: • N-doped VO_2(M1) thin films have been synthesized by annealing in NH_3 atmosphere. • The phase purity, microstructure and optical property of VO_2 thin film can be regulated by NH_3 concentration. • First-principles calculations have been carried out to study the mechanism of N-doping on energy band structures of VO_2(M1). • The energy band gaps of VO_2(M1) are tuned by substitution N-doping or interstitial N-doping. - Abstract: Research on monoclinic (M1) phase of VO_2 has attracted a great of interest for smart coating applications due to its exceptional thermochromic property. Herein, we report the results using a novel approach to synthesize N-doped VO_2(M1) thin films with high purity by heat treatment in NH_3 atmosphere. The N dopant in the film can be regulated by varying NH_3 concentration during the annealing process. We find that the N atoms are located at the interstitial sites or substitute oxygen atoms, and the V-N bonds in the VO_2 thin films increase with NH_3 concentration. The metal to insulator transition (MIT) temperature (τ_c_,_h) of the VO_2 thin film is effectively reduced from 80.0 to 62.9 °C, while the solar modulation efficiency (ΔT_s_o_l) and the modulation efficiency at 2000 nm (ΔT_2_0_0_0_n_m) are 7.36% and 55.6% respectively. The band gap of N-doped VO_2 thin films related to MIT (E_g_1) is estimated to be as low as 0.18–0.25 eV whereas the band gap associated with the visible transparency (E_g_2) is about 1.50–1.58 eV. Based on the highly accurate first-principles calculations, the E_g_1 of VO_2 (M1) is reduced after substituted or interstitial N-doping, while the E_g_2 alters with the mode of N-doping, which is excellent agreement with experimental measurement.

  18. Slow VO2 off-kinetics in skeletal muscle is associated with fast PCr off-kinetics--and inversely.

    Science.gov (United States)

    Korzeniewski, Bernard; Zoladz, Jerzy A

    2013-09-01

    The computer model of the bioenergetic system in skeletal muscle, developed previously, was used to study the effect of the characteristic decay time of the parallel activation of oxidative phosphorylation [τ(OFF)] during muscle recovery on the muscle oxygen consumption rate (Vo2) and phosphocreatine (PCr) work-to-rest transition (off)-kinetics and on the relationship between the Vo2 and PCr rest-to-work transition (on)- and off-kinetics in moderate and heavy exercise. An increase in τ(OFF) slows down the initial phase of the muscle Vo2 off-kinetics and accelerates the PCr off-kinetics. As a result, the relationship between the initial phase of the Vo2 off-kinetics (lasting approximately 3-60 s in computer simulations) and the PCr off-kinetics is inverse: the slower the former, the faster the latter. A faster initial phase of the Vo2 off-kinetics is associated with a slower late phase of the Vo2 off-kinetics, and as a result, the integral of Vo2 above baseline during recovery, representing the oxygen debt, is identical in all cases [values of τ(OFF)] for a given PCr decrease. Depending on τ(OFF), the muscle Vo2 on-kinetics was either equally fast or slower than the Vo2 off-kinetics in moderate exercise and always slower in heavy exercise. PCr on-kinetics was always faster than PCr off-kinetics. This study clearly demonstrates that τ(OFF) has a pronounced impact on the mutual relations between the muscle Vo2 and PCr on- and off-kinetics.

  19. Luminous transmittance and phase transition temperature of VO 2 ...

    African Journals Online (AJOL)

    The phase transition temperature (τc) of the films was obtained from both the transmittance and sheet resistance against temperature curves. A change in sheet resistance of 2 to 3 orders of magnitude was observed for both undoped and Ce-doped VO2 films. Comparison between undoped and doped VO2 films revealed ...

  20. Effects of training status and exercise intensity on phase II VO2 kinetics.

    Science.gov (United States)

    Koppo, Katrien; Bouckaert, Jacques; Jones, Andrew M

    2004-02-01

    To test the hypotheses that: 1) the time constant for the fast component of .VO2 kinetics (tau1) at exercise onset would be faster in trained than in untrained subjects for both moderate and heavy exercise, and that 2) tau1 would become progressively slower in untrained subjects at higher power outputs but be invariant in trained subjects. Eight untrained subjects (.VO2peak: 42.9 +/- 5.1 mL.kg-1.min-1) and seven trained cyclists (.VO2peak: 66.6 +/- 2.5 mL.kg-1.min-1) completed square-wave transitions to power outputs requiring 60% and 80% of gas exchange threshold (GET), and 50% of the difference between GET and .VO2 peak (50%Delta) from a baseline of "unloaded" cycling. .VO2 was measured breath-by-breath and individual responses were modeled using nonlinear regression techniques. A repeated measures ANOVA revealed that the tau1 was significantly smaller (i.e., the kinetics were faster) in the trained compared with the untrained subjects and that tau1 became significantly greater (i.e., the kinetics were slowed) at higher power outputs both in the untrained (60%GET: 17.8 +/- 3.8 s, 80%GET: 21.5 +/- 6.6 s, and 50%Delta: 23.5 +/- 2.8 s) and the trained (60%GET: 8.9 +/- 1.3 s, 80%GET: 11.7 +/- 2.5 s, and 50%Delta: 15.2 +/- 2.0 s) subjects (P exercise intensity domain (recruitment of higher threshold motor units.

  1. Supercapacitors based on two dimensional VO2 nanosheet electrodes in organic gel electrolyte

    KAUST Repository

    Rakhi, R.B.

    2016-10-16

    VO2 is a low band-gap semiconductor with relatively high conductivity among transition metal oxides, which makes it an interesting material for supercapacitor electrode applications. The performance of VO2 as supercapacitor electrode in organic electrolytes has never been reported before. Herein, two-dimensional nanosheets of VO2 are prepared by the simultaneous solution reduction and exfoliation from bulk V2O5 powder by hydrothermal method. A specific capacitance of 405 Fg−1 is achieved for VO2 based supercapacitor in an organic electrolyte, in three electrode configuration. The symmetric capacitor based on VO2 nanosheet electrodes and the liquid organic electrolyte exhibits an energy density of 46 Wh kg−1 at a power density of 1.4 kW kg−1 at a constant current density of 1 Ag−1. Furthermore, flexible solid-state supercapacitors are fabricated using same electrode material and Alumina-silica based gel electrolyte. The solid-state device delivers a specific capacitance of 145 Fg−1 and a device capacitance of 36 Fg−1 at a discharge current density of 1 Ag−1. Series combination of three solid state capacitors is capable of lighting up a red LED for more than 1 minute.

  2. Relationship between running kinematic changes and time limit at vVO2max

    Directory of Open Access Journals (Sweden)

    Leonardo De Lucca

    2012-06-01

    Exhaustive running at maximal oxygen uptake velocity (vVO2max can alter running kinematic parameters and increase energy cost along the time. The aims of the present study were to compare characteristics of ankle and knee kinematics during running at vVO2max and to verify the relationship between changes in kinematic variables and time limit (Tlim. Eleven male volunteers, recreational players of team sports, performed an incremental running test until volitional exhaustion to determine vVO2max and a constant velocity test at vVO2max. Subjects were filmed continuously from the left sagittal plane at 210 Hz for further kinematic analysis. The maximal plantar flexion during swing (p<0.01 was the only variable that increased significantly from beginning to end of the run. Increase in ankle angle at contact was the only variable related to Tlim (r=0.64; p=0.035 and explained 34% of the performance in the test. These findings suggest that the individuals under study maintained a stable running style at vVO2max and that increase in plantar flexion explained the performance in this test when it was applied in non-runners.

  3. Improving the electrocatalytic performance of carbon nanotubes for VO"2"+/VO_2"+ redox reaction by KOH activation

    International Nuclear Information System (INIS)

    Dai, Lei; Jiang, Yingqiao; Meng, Wei; Zhou, Huizhu; Wang, Ling; He, Zhangxing

    2017-01-01

    Highlights: • KOH-activated carbon nanotubes (CNTs) was investigated as superior catalyst for VO"2"+/VO_2"+ redox reaction for vanadium redox flow battery (VRFB) for the first time. • KOH activation for CNTs can result in the chemical etching of surface and improved wettability, accelerating the mass transfer of vanadium ions. • KOH activation can introduce many oxygen-containing groups as active sites on the surface of CNTs. • KOH-activated CNTs as positive catalyst could increase the comprehensive energy storage performance of VRFB. - Abstract: In this paper, carbon nanotubes (CNTs) was activated by KOH treatment at high temperature and investigated as catalyst for VO"2"+/VO_2"+ redox reaction for vanadium redox flow battery (VRFB). X-ray photoelectron spectroscopy results suggest that the oxygen-containing groups can be introduced on CNTs by KOH activation. The mass transfer of vanadium ions can be accelerated by chemical etching by KOH activation and improved wettability due to the introduction of hydrophilic groups. The electrochemical properties of VO"2"+/VO_2"+ redox reaction can be enhanced by introduced oxygen-containing groups as active sites. The sample treated at 900 °C with KOH/CNTs mass ratio of 3:1 (CNTs-3) exhibits the highest electrocatalytic activity for VO"2"+/VO_2"+ redox reaction. The cell using CNTs-3 as positive catalyst demonstrates the smallest electrochemical polarization, the highest capacity and efficiency among the samples. Using KOH-activated CNTs-3 can increase the average energy efficiency of the cell by 4.4%. This work suggests that KOH-activated CNTs is a low-cost, efficient and promising catalyst for VO"2"+/VO_2"+ redox reaction for VRFB system.

  4. 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.

  5. Is Recreational Soccer Effective for Improving VO2max A Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Milanović, Zoran; Pantelić, Saša; Čović, Nedim; Sporiš, Goran; Krustrup, Peter

    2015-09-01

    Soccer is the most popular sport worldwide, with a long history and currently more than 500 million active participants, of whom 300 million are registered football club members. On the basis of scientific findings showing positive fitness and health effects of recreational soccer, FIFA (Fédération Internationale de Football Association) introduced the slogan "Playing football for 45 min twice a week-best prevention of non-communicable diseases" in 2010. The objective of this paper was to perform a systematic review and meta-analysis of the literature to determine the effects of recreational soccer on maximal oxygen uptake (VO2max). Six electronic databases (MEDLINE, PubMed, SPORTDiscus, Web of Science, CINAHL and Google Scholar) were searched for original research articles. A manual search was performed to cover the areas of recreational soccer, recreational physical activity, recreational small-sided games and VO2max using the following key terms, either singly or in combination: recreational small-sided games, recreational football, recreational soccer, street football, street soccer, effect, maximal oxygen uptake, peak oxygen uptake, cardiorespiratory fitness, VO2max. The inclusion criteria were divided into four sections: type of study, type of participants, type of interventions and type of outcome measures. Probabilistic magnitude-based inferences for meta-analysed effects were based on standardised thresholds for small, moderate and large changes (0.2, 0.6 and 1.2, respectively) derived from between-subject standard deviations for baseline fitness. Seventeen studies met the inclusion criteria and were included in the systematic review and meta-analysis. Mean differences showed that VO2max increased by 3.51 mL/kg/min (95 % CI 3.07-4.15) over a recreational soccer training programme in comparison with other training models. The meta-analysed effects of recreational soccer on VO2max compared with the controls of no exercise, continuous running and strength

  6. 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

  7. 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

  8. 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

  9. Hydrothermal synthesis and electrochemical characterization of VO2 (B) with controlled crystal structures

    International Nuclear Information System (INIS)

    Jiang Wentao; Ni Juan; Yu Ke; Zhu Ziqiang

    2011-01-01

    Three different VO 2 (B) nanostructures, including urchin-like VO 2 (B), VO 2 (B) honeycombs and VO 2 (B) nanorods have been successfully fabricated through hydrothermal process by adjusting the concentrations of the oxalic acid. The microstructure and morphology of the VO 2 nanostructures were evaluated by using X-ray diffraction and scanning and transmission electron microscopies. Electrochemical properties measurements of urchin-like VO 2 (B) and VO 2 (B) honeycombs showed excellent cycling performance, especially the urchin-like VO 2 (B) exhibited higher discharge capacity and better capacity retention.

  10. A novel inorganic precipitation-peptization method for VO2 sol and VO2 nanoparticles preparation: Synthesis, characterization and mechanism.

    Science.gov (United States)

    Li, Yao; Jiang, Peng; Xiang, Wei; Ran, Fanyong; Cao, Wenbin

    2016-01-15

    In this paper, a simple, safe and cost-saving precipitation-peptization method was proposed to prepare VO2 sol by using inorganic VOSO4-NH3⋅H2O-H2O2 reactants system in air under room temperature. In this process, VOSO4 was firstly precipitated to form VO(OH)2, then monometallic species of VO(O2)(OH)(-) were formed through the coordination between VO(OH)2 and H2O2. The rearrangement of VO(O2)(OH)(-) in a nonplanar pattern and intermolecular condensation reactions result in multinuclear species. Finally, VO2 sol is prepared through the condensation reactions between the multinuclear species. After drying the obtained sol at 40°C, VO2 xerogel exhibiting monoclinic crystal structure with the space group of C2/m was prepared. The crystal structure of VO2 nanoparticles was transferred to monoclinic crystal structure with the space group of P21/c (VO2(M)) by annealing the xerogel at 550°C. Both XRD and TEM analysis indicated that the nanoparticles possess good crystallinity with crystallite size of 34.5nm as estimated by Scherrer's method. These results suggest that the VO2 sol has been prepared successfully through the proposed simple method. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Mechanisms of Attenuation of Pulmonary V'O2 Slow Component in Humans after Prolonged Endurance Training.

    Directory of Open Access Journals (Sweden)

    Jerzy A Zoladz

    Full Text Available In this study we have examined the effect of prolonged endurance training program on the pulmonary oxygen uptake (V'O2 kinetics during heavy-intensity cycling-exercise and its impact on maximal cycling and running performance. Twelve healthy, physically active men (mean±SD: age 22.33±1.44 years, V'O2peak 3198±458 mL ∙ min-1 performed an endurance training composed mainly of moderate-intensity cycling, lasting 20 weeks. Training resulted in a decrease (by ~5%, P = 0.027 in V'O2 during prior low-intensity exercise (20 W and in shortening of τp of the V'O2 on-kinetics (30.1±5.9 s vs. 25.4±1.5 s, P = 0.007 during subsequent heavy-intensity cycling. This was accompanied by a decrease of the slow component of V'O2 on-kinetics by 49% (P = 0.001 and a decrease in the end-exercise V'O2 by ~5% (P = 0.005. An increase (P = 0.02 in the vascular endothelial growth factor receptor 2 mRNA level and a tendency (P = 0.06 to higher capillary-to-fiber ratio in the vastus lateralis muscle were found after training (n = 11. No significant effect of training on the V'O2peak was found (P = 0.12. However, the power output reached at the lactate threshold increased by 19% (P = 0.01. The power output obtained at the V'O2peak increased by 14% (P = 0.003 and the time of 1,500-m performance decreased by 5% (P = 0.001. Computer modeling of the skeletal muscle bioenergetic system suggests that the training-induced decrease in the slow component of V'O2 on-kinetics found in the present study is mainly caused by two factors: an intensification of the each-step activation (ESA of oxidative phosphorylation (OXPHOS complexes after training and decrease in the ''additional" ATP usage rising gradually during heavy-intensity exercise.

  12. Mechanisms of Attenuation of Pulmonary V'O2 Slow Component in Humans after Prolonged Endurance Training.

    Science.gov (United States)

    Zoladz, Jerzy A; Majerczak, Joanna; Grassi, Bruno; Szkutnik, Zbigniew; Korostyński, Michał; Gołda, Sławomir; Grandys, Marcin; Jarmuszkiewicz, Wiesława; Kilarski, Wincenty; Karasinski, Janusz; Korzeniewski, Bernard

    2016-01-01

    In this study we have examined the effect of prolonged endurance training program on the pulmonary oxygen uptake (V'O2) kinetics during heavy-intensity cycling-exercise and its impact on maximal cycling and running performance. Twelve healthy, physically active men (mean±SD: age 22.33±1.44 years, V'O2peak 3198±458 mL ∙ min-1) performed an endurance training composed mainly of moderate-intensity cycling, lasting 20 weeks. Training resulted in a decrease (by ~5%, P = 0.027) in V'O2 during prior low-intensity exercise (20 W) and in shortening of τp of the V'O2 on-kinetics (30.1±5.9 s vs. 25.4±1.5 s, P = 0.007) during subsequent heavy-intensity cycling. This was accompanied by a decrease of the slow component of V'O2 on-kinetics by 49% (P = 0.001) and a decrease in the end-exercise V'O2 by ~5% (P = 0.005). An increase (P = 0.02) in the vascular endothelial growth factor receptor 2 mRNA level and a tendency (P = 0.06) to higher capillary-to-fiber ratio in the vastus lateralis muscle were found after training (n = 11). No significant effect of training on the V'O2peak was found (P = 0.12). However, the power output reached at the lactate threshold increased by 19% (P = 0.01). The power output obtained at the V'O2peak increased by 14% (P = 0.003) and the time of 1,500-m performance decreased by 5% (P = 0.001). Computer modeling of the skeletal muscle bioenergetic system suggests that the training-induced decrease in the slow component of V'O2 on-kinetics found in the present study is mainly caused by two factors: an intensification of the each-step activation (ESA) of oxidative phosphorylation (OXPHOS) complexes after training and decrease in the ''additional" ATP usage rising gradually during heavy-intensity exercise.

  13. Synthesis, characterization and formation mechanism of metastable phase VO2(A) nanorods

    International Nuclear Information System (INIS)

    Cheng, X.H.; Xu, H.F.; Wang, Z.Z.; Zhu, K.R.; Li, G.; Jin, Shaowei

    2013-01-01

    Graphical abstract: - Highlights: • Pure phases of VO 2 (B) and VO 2 (A) were prepared by a facile hydrothermal method. • Belt-like particles prepared at 180 °C was indexed as monoclinic VO 2 (B) phase. • Rod-like particles prepared at 230 °C was indexed as tetragonal VO 2 (A) phase. • VO 2 (A) nanorods resulted from VO 2 (B) nanobelts by assembly and crystal adjustment. - Abstract: Pure phase VO 2 (A) nanorods were synthesized via the reduction of V 2 O 5 by oxalic acid during the hydrothermal treatment. Two sets of samples were prepared by varying both system temperature and reaction time under a filling ratio of 0.40 for observing the formation and evolution of VO 2 (A) nanorods. Structures were characterized by X-ray diffraction, scanning and transmission electron microscopies, respectively. It was found that VO 2 (B) was firstly formed and then transformed into VO 2 (A) as the increasing system temperature or extending reaction time. An assembling and following crystal adjustment was proposed for explanation the formation process of VO 2 (A) from VO 2 (B). For VO 2 (A) nanorods, the phase transition temperature of 169.7 °C was higher than that of the VO 2 (A) bulk, it might be ascribed to the lower crystallinity or nonstoichiometry in VO 2 (A) nanorods. VO 2 nanostructures with controllable phases and properties should find their promising applications in a single VO 2 nanodevice

  14. Electronic structure and insulating gap in epitaxial VO2 polymorphs

    Directory of Open Access Journals (Sweden)

    Shinbuhm Lee

    2015-12-01

    Full Text Available Determining the origin of the insulating gap in the monoclinic V O2(M1 is a long-standing issue. The difficulty of this study arises from the simultaneous occurrence of structural and electronic transitions upon thermal cycling. Here, we compare the electronic structure of the M1 phase with that of single crystalline insulating V O2(A and V O2(B thin films to better understand the insulating phase of VO2. As these A and B phases do not undergo a structural transition upon thermal cycling, we comparatively study the origin of the gap opening in the insulating VO2 phases. By x-ray absorption and optical spectroscopy, we find that the shift of unoccupied t2g orbitals away from the Fermi level is a common feature, which plays an important role for the insulating behavior in VO2 polymorphs. The distinct splitting of the half-filled t2g orbital is observed only in the M1 phase, widening the bandgap up to ∼0.6 eV. Our approach of comparing all three insulating VO2 phases provides insight into a better understanding of the electronic structure and the origin of the insulating gap in VO2.

  15. The ergogenic effect of recombinant human erythropoietin on VO2max depends on the severity of arterial hypoxemia

    DEFF Research Database (Denmark)

    Robach, Paul; Calbet, Jose A L; Thomsen, Jonas J

    2008-01-01

    degrees of acute hypoxia in eight rhEpo-treated subjects. Following prolonged rhEpo treatment, the gain in systemic VO(2)max observed in normoxia (6-7%) persisted during mild hypoxia (8% at inspired O(2) fraction (F(I)O(2)) of 0.173) and was even larger during moderate hypoxia (14-17% at F(I)O(2) = 0...... redistribution of cardiac output toward the exercising legs, whereas this advantageous effect disappeared during severe hypoxia, leaving augmented CaO(2) alone insufficient for improving peak leg O(2) delivery and VO(2). Finally, that VO(2)max was largely dependent on CaO(2) during moderate hypoxia but became...

  16. VO2 Kinetics in All-out Arm Stroke, Leg Kick and Whole Stroke Front Crawl 100-m Swimming.

    Science.gov (United States)

    Rodríguez, F A; Lätt, E; Jürimäe, J; Maestu, J; Purge, P; Rämson, R; Haljaste, K; Keskinen, K L; Jürimäe, T

    2016-03-01

    The VO2 response to extreme-intensity exercise and its relationship with sports performance are largely unexplored. This study investigated the pulmonary VO2 kinetics during all-out 100-m front crawl whole stroke swimming (S), arm stroke (A) and leg kick (L). 26 male and 10 female competitive swimmers performed an all-out S trial followed by A and L of equal duration in random order. Breath-by-breath VO2 was measured using a snorkel attached to a portable gas analyzer. Mean (±SD) primary component parameters and peak blood lactate (Lapeak) during S, A, and L were, respectively: time delay (s), 14.2 ± 4.7, 14.3 ± 4.5, 15.6 ± 5.1; amplitude (ml·kg(-1)·min(-1)), 46.8 ± 6.1, 37.3 ± 6.9, 41.0 ± 4.7; time constant (τ, s): 9.2 ± 3.2, 12.4 ± 4.7, 10.1 ± 3.2; Lapeak (mmol·l(-1)), 6.8 ± 3.1, 6.3 ± 2.5, 7.9 ± 2.8. During A and L respectively, 80% and 87% of amplitude in S was reached, whereas A+L were 68% greater than in S. 100-m performance was associated to shorter cardiodynamic phase and greater VO2 amplitude and Lapeak (accounting up to 61% of performance variance), but not to τ. We conclude that (i) VO2 gain was proportional to exercise intensity and muscle mass involved, (ii) kicking is metabolically less efficient, and (iii) the main limiting factor of peak VO2 appears to be O2 delivery and not muscle extraction. © Georg Thieme Verlag KG Stuttgart · New York.

  17. Seasonal variation of VO 2 max and the VO2-work rate relationship in elite Alpine skiers.

    Science.gov (United States)

    Gross, Micah A; Breil, Fabio A; Lehmann, Andrea D; Hoppeler, Hans; Vogt, Michael

    2009-11-01

    Alpine ski performance relates closely to both anaerobic and aerobic capacities. During their competitive season, skiers greatly reduce endurance and weight training, and on-snow training becomes predominant. To typify this shift, we compared exhaustive ramp cycling and squat (SJ) and countermovement jumping (CMJ) performance in elite males before and after their competitive season. In postseason compared with preseason: 1) maximal oxygen uptake (VO 2 max) normalized to bodyweight was higher (55.2 +/- 5.2 vs 52.7 +/- 3.6 mL x kg(-1) x min(-1), P jump height was greater in SJ (47.4 +/- 4.4 vs 44.7 +/- 4.3 cm, P skiing seemingly provides an ample cardiovascular training stimulus for skiers to maintain their aerobic capacities during the racing season. We conclude that aerobic fitness and leg explosiveness can be maintained in-season but may be compromised by heavy or excessive preseason training. In addition, ramp test V O2/W slope analysis could be useful for monitoring both positive and negative responses to training.

  18. THE RELATIONSHIP BETWEEN AEROBIC POWER AND REPEATED SPRINT ABILITY IN YOUNG SOCCER PLAYERS WITH DIFFERENT LEVELS OF VO2 MAX

    Directory of Open Access Journals (Sweden)

    Rostam Alizadeh

    2010-06-01

    Full Text Available In some team sports such as soccer which is interval, athletes need to prepare themselves immediatelyfor the next activity. Therefore it is very important to have enough information on characteristics of recovery phase and quick recovery to the first situation and to have the minimum speed reduction. The purpose of this study was to determine the relationship between aerobic power and repeated sprint ability (RSA or decrementindex in young soccer players in three different levels of Vo2max. Methods: For this reason 41 volunteers were divided in to three groups with different levels of Vo2max ml.kg-1.min-1 low 37.22 ± 2.3 (n= 18, age 17.1 ± 0.9 year, height 170.6 ± 0.76 cm, weight 67.1 ± 5.05 kg medium 46.46± 1.97 ml.kg-1.min-1 (n= 13, age 17.6± 0.76year, height 173.8 ± 4.84 cm, weight 65.9 ± 4.92 kg and high 55.63 ± 1.52 ml.kg-1.min-1 (n=10, age 17.4 ±0.69 year, height 177 ± 3.23 cm, weight 71.4 ± 3.94 kg. To determine Vo2max a graded exercise test until volitional exhaustion on treadmill was used, and also RAST was used to measure RSA. The lactate accumulation was measured before and after RSA protocol. Pearson's correlation was used to determine the correlation between the aerobic power and RSA. The results indicated that there are significant relationship between Vo2max anddecremental index in low Vo2max group (r= 0.86, p= 0.001, no significant relationship medium Vo2max group (r= 0.14, p= 0.63 and negative significant relationship in high Vo2max group (r= - 0.64, p= 0.04. There are no significant relationship between Lactate accumulation and decremental index in medium (r= 0.005, p= 0.98 and high Vo2max groups (r=0.27, p= 0.45. Discussion: It is possible that the recovery of inter muscular resources relates to aerobic ability, but there are other factors effective in RSA rather than Vo2max and Lactate accumulation. The current study showed a normal curved relationship between Vo2max and RSA.

  19. Comprehensive picture of VO2 from band theory

    KAUST Repository

    Zhu, Zhiyong; Schwingenschlö gl, Udo

    2012-01-01

    The structural, electronic, and magnetic features of the metal-insulator transition from the tetragonal rutile (R) to the monoclinic (M1) phase of VO2 are well reproduced by band theory using the modified Becke-Johnson exchange potential. Based

  20. Lithiation-driven structural transition of VO2F into disordered rock-salt LixVO2F

    Czech Academy of Sciences Publication Activity Database

    Chen, R.; Maawad, E.; Knapp, M.; Ren, S.; Beran, Přemysl; Witter, R.; Hempelmann, R.

    2016-01-01

    Roč. 6, č. 69 (2016), s. 65112-65118 ISSN 2046-2069 R&D Projects: GA MŠk(CZ) LM2011019 EU Projects: European Commission(XE) 283883 - NMI3-II Institutional support: RVO:61389005 Keywords : Li- Ion batteries * rechargeble lithium batteries * VO2F Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.108, year: 2016

  1. VO2 thermochromic smart window for energy savings and generation

    Science.gov (United States)

    Zhou, Jiadong; Gao, Yanfeng; Zhang, Zongtao; Luo, Hongjie; Cao, Chuanxiang; Chen, Zhang; Dai, Lei; Liu, Xinling

    2013-10-01

    The ability to achieve energy saving in architectures and optimal solar energy utilisation affects the sustainable development of the human race. Traditional smart windows and solar cells cannot be combined into one device for energy saving and electricity generation. A VO2 film can respond to the environmental temperature to intelligently regulate infrared transmittance while maintaining visible transparency, and can be applied as a thermochromic smart window. Herein, we report for the first time a novel VO2-based smart window that partially utilises light scattering to solar cells around the glass panel for electricity generation. This smart window combines energy-saving and generation in one device, and offers potential to intelligently regulate and utilise solar radiation in an efficient manner.

  2. Gate-tunable gigantic lattice deformation in VO2

    International Nuclear Information System (INIS)

    Okuyama, D.; Hatano, T.; Nakano, M.; Takeshita, S.; Ohsumi, H.; Tardif, S.; Shibuya, K.; Yumoto, H.; Koyama, T.; Ohashi, H.; Takata, M.; Kawasaki, M.; Tokura, Y.; Iwasa, Y.; Arima, T.

    2014-01-01

    We examined the impact of electric field on crystal lattice of vanadium dioxide (VO 2 ) in a field-effect transistor geometry by in-situ synchrotron x-ray diffraction measurements. Whereas the c-axis lattice parameter of VO 2 decreases through the thermally induced insulator-to-metal phase transition, the gate-induced metallization was found to result in a significant increase of the c-axis length by almost 1% from that of the thermally stabilized insulating state. We also found that this gate-induced gigantic lattice deformation occurs even at the thermally stabilized metallic state, enabling dynamic control of c-axis lattice parameter by more than 1% at room temperature

  3. The electrochemical catalytic activity of single-walled carbon nanotubes towards VO2+/VO2+ and V3+/V2+ redox pairs for an all vanadium redox flow battery

    International Nuclear Information System (INIS)

    Li Wenyue; Liu Jianguo; Yan Chuanwei

    2012-01-01

    Highlights: ► SWCNT shows excellent electrochemical catalytic activity towards VO 2 + /VO 2+ and V 3+ /V 2+ redox couples. ► The anodic reactions are more sensitive to the surface oxygen atom content change compared with the cathodic reactions. ► The enhanced battery performance clearly demonstrated that the SWCNT is suitable to be used as an electrode catalyst for VRFB. - Abstract: Single-walled carbon nanotube (SWCNT) was used as an electrode catalyst for an all vanadium redox flow battery (VRFB). The electrochemical property of SWCNT towards VO 2 + /VO 2+ and V 3+ /V 2+ was carefully characterized by cyclic voltammetric (CV) and electrochemical impedance spectroscopy (EIS) measurements. The peak current values for these redox pairs were significantly higher on the modified glassy carbon electrode compared with those obtained on the bare electrode, suggesting the excellent electrochemical activity of the SWCNT. Moreover, it was proved that the anodic process was more dependent on the surface oxygen of the SWCNT than the cathodic process through changing its surface oxygen content. Detailed EIS analysis of different modified electrodes revealed that the charge and mass transfer processes were accelerated at the modified electrode–electrolyte interface, which could be ascribed to the large specific surface area, the surface defects and the oxygen functional groups of the SWCNT. The enhanced battery performance effectively demonstrated that the SWCNT was suitable to serve as an electrode catalyst for the VRFB.

  4. Light-induced ultrafast phase transitions in VO2 thin film

    International Nuclear Information System (INIS)

    Lysenko, S.; Rua, A.J.; Vikhnin, V.; Jimenez, J.; Fernandez, F.; Liu, H.

    2006-01-01

    Vanadium dioxide shows a passive and reversible change from a monoclinic insulator phase to a metallic tetragonal rutile structure when the sample temperature is close to and over 68 deg. C. As a kind of functional material, VO 2 thin films deposited on fused quartz substrates were successfully prepared by the pulsed laser deposition (PLD) technique. With laser illumination at 400 nm on the obtained films, the phase transition (PT) occurred. The observed light-induced PT was as fast as the laser pulse duration of 100 fs. Using a femtosecond laser system, the relaxation processes in VO 2 were studied by optical pump-probe spectroscopy. Upon a laser excitation an instantaneous response in the transient reflectivity and transmission was observed followed by a relatively longer relaxation process. The alteration is dependent on pump power. The change in reflectance reached a maximum value at a pump pulse energy between 7 and 14 mJ/cm 2 . The observed PT is associated with the optical interband transition in VO 2 thin film. It suggests that with a pump laser illuminating on the film, excitation from the d θ,ε - state of valence band to the unoccupied excited mixed d θ,ε -π* - state of the conduction band in the insulator phase occurs, followed by a resonant transition to an unoccupied excited mixed d θ,ε -π* - state of the metallic phase band

  5. Atomic Origins of Monoclinic-Tetragonal (Rutile) Phase Transition in Doped VO2 Nanowires.

    Science.gov (United States)

    Asayesh-Ardakani, Hasti; Nie, Anmin; Marley, Peter M; Zhu, Yihan; Phillips, Patrick J; Singh, Sujay; Mashayek, Farzad; Sambandamurthy, Ganapathy; Low, Ke-Bin; Klie, Robert F; Banerjee, Sarbajit; Odegard, Gregory M; Shahbazian-Yassar, Reza

    2015-11-11

    There has been long-standing interest in tuning the metal-insulator phase transition in vanadium dioxide (VO2) via the addition of chemical dopants. However, the underlying mechanisms by which doping elements regulate the phase transition in VO2 are poorly understood. Taking advantage of aberration-corrected scanning transmission electron microscopy, we reveal the atomistic origins by which tungsten (W) dopants influence the phase transition in single crystalline WxV1-xO2 nanowires. Our atomically resolved strain maps clearly show the localized strain normal to the (122̅) lattice planes of the low W-doped monoclinic structure (insulator). These strain maps demonstrate how anisotropic localized stress created by dopants in the monoclinic structure accelerates the phase transition and lead to relaxation of structure in tetragonal form. In contrast, the strain distribution in the high W-doped VO2 structure is relatively uniform as a result of transition to tetragonal (metallic) phase. The directional strain gradients are furthermore corroborated by density functional theory calculations that show the energetic consequences of distortions to the local structure. These findings pave the roadmap for lattice-stress engineering of the MIT behavior in strongly correlated materials for specific applications such as ultrafast electronic switches and electro-optical sensors.

  6. HIGHER PRECISION OF HEART RATE COMPARED WITH VO2 TO PREDICT EXERCISE INTENSITY IN ENDURANCE-TRAINED RUNNERS

    Directory of Open Access Journals (Sweden)

    Victor M. Reis

    2011-03-01

    Full Text Available The aim of the present study was to assess the precision of oxygen uptake with heart rate regression during track running in highly-trained runners. Twelve national and international level male long-distance road runners (age 30.7 ± 5.5 yrs, height 1.71 ± 0.04 m and mass 61.2 ± 5.8 kg with a personal best on the half marathon of 62 min 37 s ± 1 min 22 s participated in the study. Each participant performed, in an all-weather synthetic track five, six min bouts at constant velocity with each bout at an increased running velocity. The starting velocity was 3.33 m·s-1 with a 0.56 m·s-1 increase on each subsequent bout. VO2 and heart rate were measured during the runs and blood lactate was assessed immediately after each run. Mean peak VO2 and mean peak heart rate were, respectively, 76.2 ± 9.7 mL·kg-1·min-1 and 181 ± 13 beats·min-1. The linearity of the regressions between heart rate, running velocity and VO2 were all very high (r > 0.99 with small standard errors of regression (i.e. Sy.x < 5% at the velocity associated with the 2 and 4 mmol·L-1 lactate thresholds. The strong relationships between heart rate, running velocity and VO2 found in this study show that, in highly trained runners, it is possible to have heart rate as an accurate indicator of energy demand and of the running speed. Therefore, in this subject cohort it may be unnecessary to use VO2 to track changes in the subjects' running economy during training periods.

  7. O2 uptake kinetics during exercise at peak O2 uptake.

    Science.gov (United States)

    Scheuermann, Barry W; Barstow, Thomas J

    2003-11-01

    Compared with moderate- and heavy-intensity exercise, the adjustment of O2 uptake (VO2) to exercise intensities that elicit peak VO2 has received relatively little attention. This study examined the VO2 response of 21 young, healthy subjects (25 +/- 6 yr; mean +/- SD) during cycle ergometer exercise to step transitions in work rate (WR) corresponding to 90, 100, and 110% of the peak WR achieved during a preliminary ramp protocol (15-30 W/min). Gas exchange was measured breath by breath and interpolated to 1-s values. VO2 kinetics were determined by use of a two- or three-component exponential model to isolate the time constant (tau2) as representative of VO2 kinetics and the amplitude (Amp) of the primary fast component independent of the appearance of any VO2 slow component. No difference in VO2 kinetics was observed between WRs (tau90 = 24.7 +/- 9.0; tau100 = 22.8 +/- 6.7; tau110 = 21.5 +/- 9.2 s, where subscripts denote percent of peak WR; P > 0.05); nor in a subgroup of eight subjects was tau2 different from the value for moderate-intensity (exercise (tau2 = 25 +/- 12 s, P > 0.05). As expected, the Amp increased with increasing WRs (Amp90 = 2,089 +/- 548; Amp100 = 2,165 +/- 517; Amp110 = 2,225 +/- 559 ml/min; Amp90 vs. Amp110, P exercise, the gain of the Vo2 response (as deltaVO2/DeltaWR) is reduced for exercise transitions in the severe-intensity domain, but the approach to this gain is well described by a common time constant that is invariant across work intensities. The lower deltaVO2/deltaWR may be due to an insufficient adjustment of the cardiovascular and/or pulmonary systems that determine O2 delivery to the exercising muscles or due to recruitment of motor units with lower oxidative capacity, after the onset of exercise in the severe-intensity domain.

  8. Preparation, Characterization and Thermo-Chromic Properties of EVA/VO2 Laminate Films for Smart Window Applications and Energy Efficiency in Building

    Directory of Open Access Journals (Sweden)

    Onruthai Srirodpai

    2017-01-01

    Full Text Available Thermochromic films based on vanadium dioxide (VO2/ethylene vinyl acetate copolymer (EVA composite were developed. The monoclinic VO2 particles was firstly prepared via hydrothermal and calcination processes. The effects of hydrothermal time and tungsten doping agent on crystal structure and morphology of the calcined metal oxides were reported. After that, 1 wt % of the prepared VO2 powder was mixed with EVA compound, using two different mixing processes. It was found that mechanical properties of the EVA/VO2 films prepared by the melt process were superior to those of which prepared by the solution process. On the other hand, percentage visible light transmittance of the solution casted EVA/VO2 film was greater than that of the melt processed composite film. This was related to the different gel content of EVA rubber and state of dispersion and distribution of VO2 within the polymer matrix phase. Thermochromic behaviors and heat reflectance of the EVA/VO2 film were also verified. In overall, this study demonstrated that it was possible to develop a thermochromic film using the polymer composite approach. In this regard, the mixing condition was found to be one of the most important factors affecting morphology and thermo-mechanical properties of the films.

  9. Bragg peak and relative biological efficiency of different ions

    Czech Academy of Sciences Publication Activity Database

    Lokajíček st., Miloš; Judas, Libor; Kundrát, Pavel

    2002-01-01

    Roč. 64, Suppl. 1 (2002), S309-S309 ISSN 0167-8140 R&D Projects: GA AV ČR(CZ) KSK4055109 Keywords : Bragg peak * relative biological efficisncy * radiological mechanism Subject RIV: CC - Organic Chemistry Impact factor: 2.838, year: 2002

  10. 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

  11. 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

  12. Ultrafast dynamics during the photoinduced phase transition in VO2

    Science.gov (United States)

    Wegkamp, Daniel; Stähler, Julia

    2015-12-01

    The phase transition of VO2 from a monoclinic insulator to a rutile metal, which occurs thermally at TC = 340 K, can also be driven by strong photoexcitation. The ultrafast dynamics during this photoinduced phase transition (PIPT) have attracted great scientific attention for decades, as this approach promises to answer the question of whether the insulator-to-metal (IMT) transition is caused by electronic or crystallographic processes through disentanglement of the different contributions in the time domain. We review our recent results achieved by femtosecond time-resolved photoelectron, optical, and coherent phonon spectroscopy and discuss them within the framework of a selection of latest, complementary studies of the ultrafast PIPT in VO2. We show that the population change of electrons and holes caused by photoexcitation launches a highly non-equilibrium plasma phase characterized by enhanced screening due to quasi-free carriers and followed by two branches of non-equilibrium dynamics: (i) an instantaneous (within the time resolution) collapse of the insulating gap that precedes charge carrier relaxation and significant ionic motion and (ii) an instantaneous lattice potential symmetry change that represents the onset of the crystallographic phase transition through ionic motion on longer timescales. We discuss the interconnection between these two non-thermal pathways with particular focus on the meaning of the critical fluence of the PIPT in different types of experiments. Based on this, we conclude that the PIPT threshold identified in optical experiments is most probably determined by the excitation density required to drive the lattice potential change rather than the IMT. These considerations suggest that the IMT can be driven by weaker excitation, predicting a transiently metallic, monoclinic state of VO2 that is not stabilized by the non-thermal structural transition and, thus, decays on ultrafast timescales.

  13. Comprehensive picture of VO2 from band theory

    KAUST Repository

    Zhu, Zhiyong

    2012-08-28

    The structural, electronic, and magnetic features of the metal-insulator transition from the tetragonal rutile (R) to the monoclinic (M1) phase of VO2 are well reproduced by band theory using the modified Becke-Johnson exchange potential. Based on this description, we identify a tendency for monoclinic charge ordering in the R phase due to electronic correlations as the origin of the phase transition. Whereas, the structural changes are crucial for the gap opening in the M1 phase, spin degeneracy in both phases is stabilized by correlation-induced delocalization of the V3d electrons.

  14. 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.

  15. Elevated transition temperature in Ge doped VO2 thin films

    Science.gov (United States)

    Krammer, Anna; Magrez, Arnaud; Vitale, Wolfgang A.; Mocny, Piotr; Jeanneret, Patrick; Guibert, Edouard; Whitlow, Harry J.; Ionescu, Adrian M.; Schüler, Andreas

    2017-07-01

    Thermochromic GexV1-xO2+y thin films have been deposited on Si (100) substrates by means of reactive magnetron sputtering. The films were then characterized by Rutherford backscattering spectrometry (RBS), four-point probe electrical resistivity measurements, X-ray diffraction, and atomic force microscopy. From the temperature dependent resistivity measurements, the effect of Ge doping on the semiconductor-to-metal phase transition in vanadium oxide thin films was investigated. The transition temperature was shown to increase significantly upon Ge doping (˜95 °C), while the hysteresis width and resistivity contrast gradually decreased. The precise Ge concentration and the film thickness have been determined by RBS. The crystallinity of phase-pure VO2 monoclinic films was confirmed by XRD. These findings make the use of vanadium dioxide thin films in solar and electronic device applications—where higher critical temperatures than 68 °C of pristine VO2 are needed—a viable and promising solution.

  16. Preparation and modification of VO2 thin film on R-sapphire substrate by rapid thermal process

    International Nuclear Information System (INIS)

    Zhu Nai-Wei; Hu Ming; Xia Xiao-Xu; Wei Xiao-Ying; Liang Ji-Ran

    2014-01-01

    The VO 2 thin film with high performance of metal–insulator transition (MIT) is prepared on R-sapphire substrate for the first time by magnetron sputtering with rapid thermal process (RTP). The electrical characteristic and THz transmittance of MIT in VO 2 film are studied by four-point probe method and THz time domain spectrum (THz-TDS). X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and search engine marketing (SEM) are employed to analyze the crystalline structure, valence state, surface morphology of the film. Results indicate that the properties of VO 2 film which is oxidized from the metal vanadium film in oxygen atmosphere are improved with a follow-up RTP modification in nitrogen atmosphere. The crystallization and components of VO 2 film are improved and the film becomes compact and uniform. A better phase transition performance is shown that the resistance changes nearly 3 orders of magnitude with a 2-°C hysteresis width and the THz transmittances are reduced by 64% and 60% in thermal and optical excitation respectively. (interdisciplinary physics and related areas of science and technology)

  17. Phase-field model of insulator-to-metal transition in VO2 under an electric field

    Science.gov (United States)

    Shi, Yin; Chen, Long-Qing

    2018-05-01

    The roles of an electric field and electronic doping in insulator-to-metal transitions are still not well understood. Here we formulated a phase-field model of insulator-to-metal transitions by taking into account both structural and electronic instabilities as well as free electrons and holes in VO2, a strongly correlated transition-metal oxide. Our phase-field simulations demonstrate that in a VO2 slab under a uniform electric field, an abrupt universal resistive transition occurs inside the supercooling region, in sharp contrast to the conventional Landau-Zener smooth electric breakdown. We also show that hole doping may decouple the structural and electronic phase transitions in VO2, leading to a metastable metallic monoclinic phase which could be stabilized through a geometrical confinement and the size effect. This work provides a general mesoscale thermodynamic framework for understanding the influences of electric field, electronic doping, and stress and strain on insulator-to-metal transitions and the corresponding mesoscale domain structure evolution in VO2 and related strongly correlated systems.

  18. Crystallization Mechanism and Phase Transition Properties of W-doped VO2 Synthesized by Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    LI Yao

    2017-11-01

    Full Text Available VO2 sol was firstly prepared using vanadyl sulfate as a vanadium source by precipitation-peptization method. Then tungsten(W doping vanadium dioxide(W-VO2 was prepared by hydrothermal crystallization of prepared sol with the presence of ammonium metatungstate. The morphologies, crystal structure of the as-prepared samples and phase transition properties were studied by X-ray diffraction(XRD, field emission scanning electron microscope(FESEMand differential scanning calorimetry(DSC analysis. The results indicate that rod-like W-VO2(B crystal with length of 1-2μm and radius of 100-200nm is firstly formed during hydrothermal treatment for 4-48h at 280℃, then the rod-like crystal dissolves gradually and sheet-like or snowflake-like crystal is formed with the phase transition from W-VO2(B to W-VO2(M and eventually, the W-VO2(M crystals can further grow up while the W-VO2(B gradually dissolves; the phase transition temperature of VO2 decreases with the increase in W doping content, and the phase transition temperature of W-VO2(M reduces to about 28℃ when the nominal dopant concentration is 6.0%(atom fraction.The "nucleation-growth-transformation-ripening" mechanism is proposed as the formation mechanism based on the hydrothermal crystallization and morphological evolution process of W-VO2(M.

  19. Research progress of VO2 thin film as laser protecting material

    Science.gov (United States)

    Liu, Zhiwei; Lu, Yuan; Hou, Dianxin

    2018-03-01

    With the development of laser technology, the battlefield threat of directional laser weapons is becoming more and more serious. The blinding and destruction caused by laser weapons on the photoelectric equipment is an important part of the current photo-electronic warfare. The research on the defense technology of directional laser weapons based on the phase transition characteristics of VO2 thin films is an important subject. The researches of VO2 thin films are summarized based on review these points: the preparation methods of VO2 thin films, phase transition mechanism, phase transition temperature regulating, interaction between VO2 thin films and laser, and the application prospect of vo2 thin film as laser protecting material. This paper has some guiding significance for further research on the VO2 thin films in the field of defense directional laser weapons.

  20. Potassium vanadium selenite, K(VO2)3(SeO3)2

    International Nuclear Information System (INIS)

    Harrison, W.T.A.; Dussack, L.L.; Jacobson, A.J.

    1995-01-01

    The hydrothermal synthesis and single-crystal structure of potassium vanadium(V) selenite, K(VO 2 ) 3 (SeO 3 ) 2 , are reported. K(VO 2 ) 3 (SeO 3 ) 2 is a layered phase based on a hexagonal tungsten-oxide-like array of corner-sharing VO 6 octahedra capped by Se atoms, and is isostructural with NH 4 (VO 2 ) 3 (SeO 3 ) 2 . (orig.)

  1. Temperature-agile and structure-tunable optical properties of VO2/Ag thin films

    International Nuclear Information System (INIS)

    Zhang, X.R.; Hu, X.; Wang, W.; Zhao, Y.; Reinhardt, K.; Knize, R.J.; Lu, Yalin

    2012-01-01

    By integrating together VO 2 's unique near-room-temperature (RT) semiconductor-metal (S-M) phase transition with a thin silver (Ag) layer's plasmonic properties, VO 2 /Ag multilayers could present a much enhanced optical transmission change when increasing the temperature from RT to over VO 2 's S-M phase-transition temperature. Changing VO 2 and Ag layer thicknesses can also significantly tune their transmission and absorption properties, which could lead to a few useful designs in optoelectronic and energy-saving industries. (orig.)

  2. Phase coexistence in the metal-insulator transition of a VO2 thin film

    International Nuclear Information System (INIS)

    Chang, Y.J.; Koo, C.H.; Yang, J.S.; Kim, Y.S.; Kim, D.H.; Lee, J.S.; Noh, T.W.; Kim, Hyun-Tak; Chae, B.G.

    2005-01-01

    Vanadium dioxide (VO 2 ) shows a metal-insulator transition (MIT) near room temperature, accompanied by an abrupt resistivity change. Since the MIT of VO 2 is known to be a first order phase transition, it is valuable to check metallic and insulating phase segregation during the MIT process. We deposited (100)-oriented epitaxial VO 2 thin films on R-cut sapphire substrates. From the scanning tunneling spectroscopy (STS) spectra, we could distinguish metallic and insulating regions by probing the band gap. Optical spectroscopic analysis also supported the view that the MIT in VO 2 occurs through metal and insulator phase coexistence

  3. Optimization of thermochromic VO2-based structures with tunable thermal emissivity

    International Nuclear Information System (INIS)

    Li Voti, R.; Larciprete, M.C.; Leahu, G.L.; Bertolotti, M.; Sibilia, C.

    2013-01-01

    In this paper we design and simulate VO 2 /metal multilayers to obtain a large tunability of the thermal emissivity of IR filters in the typical MWIR window of many infrared cameras. The multilayer structure is optimized to realise a low-emissivity filter at high temperatures useful for military purposes. The values of tunability found for VO 2 /metal multilayers are larger than the value for a single thick layer of VO 2 . Innovative SiO 2 /VO 2 synthetic opals are also investigated to enhance the optical tunability by combining the properties of a 3D periodic structure and the specific optical properties of vanadium dioxide.

  4. [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.

  5. Higher Precision of Heart Rate Compared with VO2 to Predict Exercise Intensity in Endurance-Trained Runners.

    Science.gov (United States)

    Reis, Victor M; den Tillaar, Roland Van; Marques, Mario C

    2011-01-01

    The aim of the present study was to assess the precision of oxygen uptake with heart rate regression during track running in highly-trained runners. Twelve national and international level male long-distance road runners (age 30.7 ± 5.5 yrs, height 1.71 ± 0.04 m and mass 61.2 ± 5.8 kg) with a personal best on the half marathon of 62 min 37 s ± 1 min 22 s participated in the study. Each participant performed, in an all-weather synthetic track five, six min bouts at constant velocity with each bout at an increased running velocity. The starting velocity was 3.33 m·s(-1) with a 0.56 m·s(-1) increase on each subsequent bout. VO2 and heart rate were measured during the runs and blood lactate was assessed immediately after each run. Mean peak VO2 and mean peak heart rate were, respectively, 76.2 ± 9.7 mL·kg(-1)·min(-1) and 181 ± 13 beats·min(-1). The linearity of the regressions between heart rate, running velocity and VO2 were all very high (r > 0.99) with small standard errors of regression (i.e. Sy.x at the velocity associated with the 2 and 4 mmol·L(-1) lactate thresholds). The strong relationships between heart rate, running velocity and VO2 found in this study show that, in highly trained runners, it is possible to have heart rate as an accurate indicator of energy demand and of the running speed. Therefore, in this subject cohort it may be unnecessary to use VO2 to track changes in the subjects' running economy during training periods. Key pointsHeart rate is used in the control of exercise intensity in endurance sports.However, few studies have quantified the precision of its relationship with oxygen uptake in highly trained runners.We evaluated twelve elite half-marathon runners during track running at various intensities and established three regressions: oxygen uptake / heart rate; heart rate / running velocity and oxygen uptake / running velocity.The three regressions presented, respectively, imprecision of 4,2%, 2,75% and 4,5% at the velocity

  6. Componente lento do VO2 em crianças durante exercício pesado de corrida: análise com base em diferentes modelos matemáticos Componente lento de VO2 en niños durante ejercicio arduo de carrera: análisis con base en diferentes modelos matemáticos Slow component of VO2 in children during running exercise performed at heavy intensity domain: analysis with different mathematical models

    Directory of Open Access Journals (Sweden)

    Fabiana Andrade Machado

    2006-12-01

    . Participaron del estudio 8 niños del sexo masculino (11,92 ± 0,63 años; 44,06 ± 13,01 kg; 146,63 ± 7,25 cm; y niveles de madurez sexual 1 y 2, aparentemente saludables, no entrenados, que realizaron en diferentes días: 1 Test incremental en la cinta rodante para determinar el consumo de oxígeno de pico (VO2pico y del límite de lactato (LL; y 2 Dos tests de carga constante en cinta rodante durante seis minutos a intensidad de 75%delta [75%delta = LL + 0,75 x (VO2pico - LL]. Para determinar el CL usamos: a modelo matemático de tres términos (Exp3; y b la diferencia en el VO2 entre el sexto y el tercer minuto de ejercicio (deltaVO2 6-3 min. El CL fue expresado en valores absolutos (ml/min y también como contribución porcentual de CL para el aumento de VO2 al final del ejercicio (%CL. El CL determinado por el modelo Exp3 (129,69 ± 75,71 ml/min y 8,4 ± 2,92% fue significativamente mayor al que fue obtenido por el modelo deltaVO2 6-3 min (68,69 ± 102,54 ml/min y 3,6 ± 7,34%. Por tanto, los valores de CL obtenidos en niños durante el ejercicio de carrera realizado en dominio pesado (75%delta son dependientes del modelo de análisis (Exp3 x deltaVO2 6-3 min.The purpose of this study was to identify and quantify the magnitude of the slow component of VO2 (SC in children during running exercise, performed at heavy intensity domain (75%delta, using two different mathematical models: a three-exponential model and; b deltaVO2 6-3 min. Eight healthy male children (11.92 ± 0.63 years; 44.06 ± 13.01 kg; 146.63 ± 7.25 cm; and sexual maturity levels 1 and 2, not trained, performed in different days the following tests: 1 incremental running treadmill test to determine the peak oxygen uptake (VO2peak and the lactate threshold (LT; and 2 two transitions from baseline to 75%delta [75%D = LT + 0.75 x (VO2 peak - LT] for six minutes on treadmill. The SC was deter mined by two models: a three-exponential model (Exp3; and b the VO2 difference between the sixth and the third

  7. Epitaxial growth of higher transition-temperature VO2 films on AlN/Si

    Directory of Open Access Journals (Sweden)

    Tetiana Slusar

    2016-02-01

    Full Text Available We report the epitaxial growth and the mechanism of a higher temperature insulator-to-metal-transition (IMT of vanadium dioxide (VO2 thin films synthesized on aluminum nitride (AlN/Si (111 substrates by a pulsed-laser-deposition method; the IMT temperature is TIMT ≈ 350 K. X-ray diffractometer and high resolution transmission electron microscope data show that the epitaxial relationship of VO2 and AlN is VO2 (010 ‖ AlN (0001 with VO2 [101] ‖   AlN   [ 2 1 ̄ 1 ̄ 0 ] zone axes, which results in a substrate-induced tensile strain along the in-plane a and c axes of the insulating monoclinic VO2. This strain stabilizes the insulating phase of VO2 and raises TIMT for 10 K higher than TIMT single crystal ≈ 340 K in a bulk VO2 single crystal. Near TIMT, a resistance change of about four orders is observed in a thick film of ∼130 nm. The VO2/AlN/Si heterostructures are promising for the development of integrated IMT-Si technology, including thermal switchers, transistors, and other applications.

  8. MAXIMAL OXIGEN UPTAKE (VO2 MAX AS THE INDICATOR OF PHYSICAL WORKING CAPACITY IN SPORTSMEN

    Directory of Open Access Journals (Sweden)

    Zvezdana Rajkovaca

    2005-12-01

    Full Text Available The term “aerobic capacity” represents the sum of aerobic metabolic processes in human organism. It is the basis of the physical working capacity. Value of the maximal oxygen uptake (VO2max is the best indicator for the aerobic capacity evaluation.The purpose of this study was to check the possibility of using VO2max as the indicator of aerobic capacity in sportsmen and to check differences in VO2max values in regard to non-sportsmen.The goals were: 1.Analyses of the VO2max values in sportsmen of various sports 2. Comparison of values of sportsmen with the values of non-sportsmen.This study included 67 sportsmen (rowers, football players and judoists and 28 nonsportsmen. VO2max was measured by using a direct method.The results obtained show statistically higher VO2max values in rowers (4,52 L/min - 55,8 mL/kg/min in regard to football players (4,2 L/min – 53,6 mL/kg/min, judoists (3,58 L/min - 47,2 mL/ kg/min and non-sportsmen (3,28 L/min – 42,3 mL/kg/min. Successful rowing requires high anaerobic capacity and, therefore, high VO2max.These results show higher values of VO2max in sportsmen in regard to non-sportsmen, which is the result of training only.

  9. VO2 /TiN Plasmonic Thermochromic Smart Coatings for Room-Temperature Applications.

    Science.gov (United States)

    Hao, Qi; Li, Wan; Xu, Huiyan; Wang, Jiawei; Yin, Yin; Wang, Huaiyu; Ma, Libo; Ma, Fei; Jiang, Xuchuan; Schmidt, Oliver G; Chu, Paul K

    2018-03-01

    Vanadium dioxide/titanium nitride (VO 2 /TiN) smart coatings are prepared by hybridizing thermochromic VO 2 with plasmonic TiN nanoparticles. The VO 2 /TiN coatings can control infrared (IR) radiation dynamically in accordance with the ambient temperature and illumination intensity. It blocks IR light under strong illumination at 28 °C but is IR transparent under weak irradiation conditions or at a low temperature of 20 °C. The VO 2 /TiN coatings exhibit a good integral visible transmittance of up to 51% and excellent IR switching efficiency of 48% at 2000 nm. These unique advantages make VO 2 /TiN promising as smart energy-saving windows. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Theoretical study of the local structures and the EPR parameters for RLNKB glasses with VO2+ and Cu2+ dopants

    Science.gov (United States)

    Ding, Chang-Chun; Wu, Shao-Yi; Wu, Li-Na; Zhang, Li-Juan; Peng, Li; Wu, Ming-He; Teng, Bao-Hua

    2018-02-01

    The electron paramagnetic resonance (EPR) parameters and local structures for impurities VO2+ and Cu2+ in RO-Li2O-Na2O-K2O-B2O3 (RLNKB; R = Zn, Mg, Sr and Ba) glasses are theoretically investigated by using the perturbation formulas of the EPR parameters for tetragonally compressed octahedral 3d1 and tetragonally elongated octahedral 3d9 clusters, respectively. The VO2+ and Cu2+ dopants are found to undergo the tetragonal compression (characterized by the negative relative distortion ratios ρ ≈ -3%, -0.98%, -1% and -0.8% for R = Zn, Mg, Sr and Ba) and elongation (characterized by the positive relative distortion ratios ρ ≈ 29%, 17%, 16% and 28%), respectively, due to the Jahn-Teller effect. Both dopants show similar overall decreasing trends of cubic field parameter Dq and covalency factor N with decreasing electronegativity of alkali earth cation R. The conventional optical basicities Λth and local optical basicities Λloc are calculated for both systems, and the local Λloc are higher for Cu2+ than for VO2+ in the same RLNKB glass, despite the opposite relationship for the conventional Λth. This point is supported by the weaker covalency or stronger ionicity for Cu2+ than VO2+ in the same RLNKB system, characterized by the larger N in the former. The above comparative analysis on the spectral and local structural properties would be helpful to understand structures and spectroscopic properties for the similar oxide glasses with transition-metal dopants of complementary electronic configurations.

  11. The effect of a peer on VO2 and game choice in 6-10 year old children

    Directory of Open Access Journals (Sweden)

    Lee Anne Siegmund

    2014-06-01

    Full Text Available Relative to sedentary video games (e.g., Playstation 2 (PS2, playing physically active video games (e.g., Nintendo Wii (Wii significantly increases caloric expenditure in children. Studies have demonstrated that the presence of a peer increases physical activity in children. We sought to determine if children would expend more energy and find playing Wii more motivating than PS2 when with a peer. Seventeen children (age 8.5 ± 0.4 years rested, played PS2 and Wii Sports Boxing for 10 minutes each, in two conditions: one in which the children rested/played the games alone (alone condition and another in which they played with a peer (peer condition. Oxygen consumption (VO2, and liking (visual analog scale was assessed for each 10-minute condition. After three 10-minute resting/gaming conditions, motivation was assessed using a relative reinforcing value task (RRV in which children performed computer mouse presses to gain additional access for either PS2 or Wii. VO2 was greater (p Conclusion: The presence of a peer increased VO2 during Wii play for boys but not girls. Surprisingly, the presence of a peer decreased children’s motivation to play Wii versus PS2.

  12. Graphene/VO2 hybrid material for high performance electrochemical capacitor

    International Nuclear Information System (INIS)

    Deng, Lingjuan; Zhang, Gaini; Kang, Liping; Lei, Zhibin; Liu, Chunling; Liu, Zong-Huai

    2013-01-01

    Graphical abstract: Graphene/VO 2 hybrid materials are prepared by one-step simultaneous hydrothermal reduction technology. The prepared graphene (1.0)/VO 2 hybrid material shows a specific capacitances of 225 F g −1 in 0.5 mol L −1 K 2 SO 4 solution. Furthermore, an asymmetric electrochemical capacitor with graphene (1.0)/VO 2 as a positive electrode and graphene as a negative electrode is assembled, and it can work in a cell voltage of 1.7 V and show excellent capacitive property. - Highlights: • Graphene/VO 2 hybrid material has been prepared by one-step hydrothermal reduction. • Graphene/VO 2 hybrid material exhibits high specific capacitance. • An asymmetric capacitor working at 1.7 V in aqueous solution is assembled based on graphene/VO 2 electrode. • The asymmetric capacitor exhibits high energy density. - Abstract: Vanadium oxides have attracted significant attention for electrochemical capacitor because of their extensive multifunctional properties. In the present work, graphene/VO 2 (RG/VO 2 ) hybrid materials with different RG amounts are prepared in a mixture of ammonium vanadate, formic acid and graphite oxide (GO) nanosheets by one-step simultaneous hydrothermal reduction technology. The hydrothermal treatment makes the reduction of GO into RG and the formation of VO 2 particles with starfruit morphology. The starfruit-like VO 2 particles are uniformly embedded in the hole constructed by RG nanosheets, which makes the electrode–electrolyte contact better. A high specific capacitance of 225 F g −1 has been achieved for RG(1.0)/VO 2 electrode with RG content of 26 wt% in 0.5 mol L −1 K 2 SO 4 electrolyte. An asymmetrical electrochemical capacitor is assembled by using RG(1.0)/VO 2 as positive electrode and RG as negative electrode, and it can be reversibly charged–discharged at a cell voltage of 1.7 V in 0.5 mol L −1 K 2 SO 4 electrolyte. The asymmetrical capacitor can deliver an energy density of 22.8 Wh kg −1 at a power density

  13. Study of substitution reactions of ligands in VO2+ complexes in toluene solutions by ESR method

    International Nuclear Information System (INIS)

    Lundkvist, R.; Panfilov, A.T.; Kalinichenko, N.B.; Marov, I.N.; AN SSSR, Moscow. Inst. Geokhimii i Analiticheskoj Khimii)

    1976-01-01

    Kinetics and equilibrium of stepwise substitution of ligands have been investigated at different temperatures for the complexes of oxovanadium (4) with salicylaldoxime, 8-oxyquinoline, acetylacetone, benzoylacetone, and tenoyltrifluoroacetone. The relative complexability of these ligands in toluene has been studied. The parameters of spin-Hamiltonian of EPR spectra of the VO 2+ complexes have been determined. The equilibrium constants, the rate constants, and activation energy have been found for the substitution reactions of ligands in the complexes VOA 2 : VOA 2 +HB=VOAB+HA; VOAB+HB=VOB 2 +HA, where HA and HB are the ligands with different donor atoms. The mixed complexes have been detected of the general formula VOAB, where HA is salicylaldoxime or 8-oxyquinoline and HB is β-diketone

  14. The influence of VO2(B nanobelts on thermal decomposition of ammonium perchlorate

    Directory of Open Access Journals (Sweden)

    Zhang Yifu

    2015-09-01

    Full Text Available The influence of vanadium dioxide VO2(B on thermal decomposition of ammonium perchlorate (AP has not been reported before. In this contribution, the effect of VO2(B nanobelts on the thermal decomposition of AP was investigated by the Thermo- Gravimetric Analysis and Differential Thermal Analysis (TG/DTA. VO2(B nanobelts were hydrothermally prepared using peroxovanadium (V complexes, ethanol and water as starting materials. The thermal decomposition temperatures of AP in the presence of I wt.%, 3 wt.% and 6 wt.% of as-obtained VO2VO2(B nanobelts had a great influence on the thermal decomposition temperature of AP Furthermore, the influence of the corresponding V2Os, which was obtained by thermal treatment of VO2(B nanobelts, on the thermal decomposition of AP was also investigated. The resufs showed that VO2(B nanobelts had a greater influence on the thermal decomposition temperature of AP than that of V2Os.

  15. Compare the phase transition properties of VO2 films from infrared to terahertz range

    Science.gov (United States)

    Liang, Shan; Shi, Qiwu; Huang, Wanxia; Peng, Bo; Mao, Zhenya; Zhu, Hongfu

    2018-06-01

    VO2 with reversible semiconductor-metal phase transition properties is particularly available for the application in smart opto-electrical devices. However, there are rare reports on comparing its phase transition properties at different ranges. In this study, the VO2 films are designed with the similar crystalline structure and stoichiometry, but different morphologies by inorganic and organic sol-gel methods, and their phase transition characteristics are compared both at infrared and terahertz range. The results indicate that the VO2 film prepared by inorganic sol-gel method shows more compact nanostructure. It results in larger resistivity change, infrared and terahertz switching ratio in the VO2 film. Moreover, it presents that the phase transition intensity of VO2 film in terahertz range is more sensitive to its microstructure. This work is helpful for understanding the susceptibility of terahertz switching properties of VO2 to its microstructure. And it can provide insights for the applications of VO2 in terahertz smart devices.

  16. Efek minuman kombinasi maltodekstrin dan vitamin C terhadap VO2maks atlet sepak bola

    Directory of Open Access Journals (Sweden)

    Desty Ervira Puspaningtyas

    2015-07-01

    Full Text Available Background: VO2max is one of win determiner in a game. Athletes receive training to improve technical skills, tactical skills, and physiology functions that can support the improvement of VO2max, so they can improve their achievement. Maltodextrin and vitamin C can be used as an ingredient for beverage products which can improve VO2max. Objective: To assess the effect of maltodextrin and vitamin C combination drink on VO2max in soccer athletes. Method: Type of this study was experimental design with the same subject design. The study was conducted from January 2014 until June 2014 at Culinary Laboratory Universitas Gadjah Mada (UGM and Stadium of Universitas Negeri Yogyakarta (UNY. Subjects of this study were 14 soccer players coming from Universitas Negeri Yogyakarta (UNY. Every subject had to fulfill the inclusion and exclusion criteria, and the subjects were chosen by purposive sampling. In the first treatment, subjects received the combination drink―a drink with a composition 15% of maltodextrin and 250 mg of vitamin C in 300 mL. After 6 days washout period, subjects received 300 mL plain water. Drinks were given 30 minutes before VO2max test. VO2max test method used in this study was yo-yo intermittent recovery test level 2 (IR-2. Results: VO2max when subjects consumed maltodextrin and vitamin C combination drink was significantly lower than VO2max when athletes consumed plain water (p=0,0000. Conclusion: Maltodextrin and vitamin C combination drink was less effective than plain water to enhance VO2max.

  17. VV and VO2 defects in silicon studied with hybrid density functional theory

    KAUST Repository

    Christopoulos, Stavros Richard G

    2014-12-07

    The formation of VO (A-center), VV and VO2 defects in irradiated Czochralski-grown silicon (Si) is of technological importance. Recent theoretical studies have examined the formation and charge states of the A-center in detail. Here we use density functional theory employing hybrid functionals to analyze the formation of VV and VO2 defects. The formation energy as a function of the Fermi energy is calculated for all possible charge states. For the VV and VO2 defects double negatively charged and neutral states dominate, respectively.

  18. Thin-film VO2 submillimeter-wave modulators and polarizers

    International Nuclear Information System (INIS)

    Fan, J.C.C.; Fetterman, H.R.; Bachner, F.J.; Zavracky, P.M.; Parker, C.D.

    1977-01-01

    Submillimeter-wave modulators and switchable polarizers have been fabricated from VO 2 thin films deposited on sapphire substrates. By passing electric current pulses through elements made from these films, the films can be thermally cycled through the insulator-to-metal transition that occurs in VO 2 at about 65 degreeC. In the insulating state, the films are found to have negligible effect on the transmission at submillimeter wavelengths, while above the phase transition the transmission is strongly reduced by the free-electron effects characteristic of a metal. Other possible applications of such switchable VO 2 elements include variable bandpass filters and diffraction grating beam-steering devices

  19. The effect of a peer on VO2 and game choice in 6–10 year old children

    Science.gov (United States)

    Siegmund, Lee A.; Naylor, Jonathan B.; Santo, Antonio S.; Barkley, Jacob E.

    2014-01-01

    Relative to sedentary video games (e.g., Playstation 2®), playing physically active video games (e.g., Nintendo Wii Sports Boxing®) significantly increases caloric expenditure in children. Studies have demonstrated that the presence of a peer increases physical activity in children. We sought to determine if children would expend more energy and find playing the “exergame” (Wii) more motivating than the sedentary video game (Playstation 2) when with a peer. Seventeen children (age 8.5 ± 0.4 years) rested, played the sedentary video game and “exergame” for 10 min each, in two conditions: one in which the children rested/played the games alone (alone condition) and another in which they played with a peer (peer condition). Oxygen consumption (VO2), and liking (visual analog scale) was assessed for each 10-min condition. After three 10-min resting/gaming conditions, motivation was assessed using a relative reinforcing value task in which children performed computer mouse presses to gain additional access for either the sedentary video game or “exergame.” VO2 was greater (p 4.1 ml·kg−1·min−1) vs. rest (mean = 5.14 ± 1.46 ml·kg−1·min−1) and the sedentary video game (mean = 5.83 ± 2.1 ml·kg−1·min−1). During the peer condition, there were no significant differences (p > 0.05) in VO2 relative to the alone condition. In an exploratory analysis boys exhibited a greater (p = 0.02) increase in VO2 from rest to “exergame” (Δ 9.0 ± 3.7 ml·kg−1·min−1), relative to girls (Δ 4.9 ± 2.9 ml·kg−1·min−1). Boys showed a significantly greater increase (p = 0.05) in VO2 from the resting condition to “exergame” in the presence of a peer (Δ 11.1 ± 5.3 ml·kg−1·min−1) vs. the alone condition (Δ 6.8 ± 3.1 ml·kg−1 ·min−1). Liking was significantly (p 4.0 ± 2.8 cm). Motivation for “exergame” significantly decreased (p = 0.03) from alone (340.8 ± 106.8 presses) to the peer condition (147.8 ± 81.6 presses). Conclusion

  20. The effect of a peer on VO2 and game choice in 6-10 year old children.

    Science.gov (United States)

    Siegmund, Lee A; Naylor, Jonathan B; Santo, Antonio S; Barkley, Jacob E

    2014-01-01

    Relative to sedentary video games (e.g., Playstation 2®), playing physically active video games (e.g., Nintendo Wii Sports Boxing®) significantly increases caloric expenditure in children. Studies have demonstrated that the presence of a peer increases physical activity in children. We sought to determine if children would expend more energy and find playing the "exergame" (Wii) more motivating than the sedentary video game (Playstation 2) when with a peer. Seventeen children (age 8.5 ± 0.4 years) rested, played the sedentary video game and "exergame" for 10 min each, in two conditions: one in which the children rested/played the games alone (alone condition) and another in which they played with a peer (peer condition). Oxygen consumption (VO2), and liking (visual analog scale) was assessed for each 10-min condition. After three 10-min resting/gaming conditions, motivation was assessed using a relative reinforcing value task in which children performed computer mouse presses to gain additional access for either the sedentary video game or "exergame." VO2 was greater (p 4.1 ml·kg(-1)·min(-1)) vs. rest (mean = 5.14 ± 1.46 ml·kg(-1)·min(-1)) and the sedentary video game (mean = 5.83 ± 2.1 ml·kg(-1)·min(-1)). During the peer condition, there were no significant differences (p > 0.05) in VO2 relative to the alone condition. In an exploratory analysis boys exhibited a greater (p = 0.02) increase in VO2 from rest to "exergame" (Δ 9.0 ± 3.7 ml·kg(-1)·min(-1)), relative to girls (Δ 4.9 ± 2.9 ml·kg(-1)·min(-1)). Boys showed a significantly greater increase (p = 0.05) in VO2 from the resting condition to "exergame" in the presence of a peer (Δ 11.1 ± 5.3 ml·kg(-1)·min(-1)) vs. the alone condition (Δ 6.8 ± 3.1 ml·kg(-1) ·min(-1)). Liking was significantly (p 4.0 ± 2.8 cm). Motivation for "exergame" significantly decreased (p = 0.03) from alone (340.8 ± 106.8 presses) to the peer condition (147.8 ± 81.6 presses). VO2 was greater during "exergame

  1. High performance of solvothermally prepared VO2(B as anode for aqueous rechargeable lithium batteries

    Directory of Open Access Journals (Sweden)

    Milošević Sanja

    2015-01-01

    Full Text Available The VO2 (B was synthesized via a simple solvothermal route at 160oC in ethanol. The initial discharge capacity of VO2 (B anode, in saturated aqueous solution of LiNO3, was 177 mAh g-1 at a current rate of 50 mA g-1. After 50 cycles capacity fade was 4%, but from 20th-50th cycle no capacity drop was observed. The VO2 (B has shown very good cyclability at current rate of even 1000 mA g-1 with initial discharge capacity of 92 mAh g-1. The excellent electrochemical performance of VO2 (B was attributed to the stability of micro-nano structures to repeated intercalation /deintercalation process, very good electronic conductivity as well as the very low charge transfer resistance in the aqueous electrolyte. [Projekat Ministarstva nauke Republike Srbije, br. III45014

  2. Selective scanning tunneling microscope light emission from rutile phase of VO2.

    Science.gov (United States)

    Sakai, Joe; Kuwahara, Masashi; Hotsuki, Masaki; Katano, Satoshi; Uehara, Yoichi

    2016-09-28

    We observed scanning tunneling microscope light emission (STM-LE) induced by a tunneling current at the gap between an Ag tip and a VO2 thin film, in parallel to scanning tunneling spectroscopy (STS) profiles. The 34 nm thick VO2 film grown on a rutile TiO2 (0 0 1) substrate consisted of both rutile (R)- and monoclinic (M)-structure phases of a few 10 nm-sized domains at room temperature. We found that STM-LE with a certain photon energy of 2.0 eV occurs selectively from R-phase domains of VO2, while no STM-LE was observed from M-phase. The mechanism of STM-LE from R-phase VO2 was determined to be an interband transition process rather than inverse photoemission or inelastic tunneling processes.

  3. VO2 nanoparticles on edge orientated graphene foam for high rate lithium ion batteries and supercapacitors

    Science.gov (United States)

    Ren, Guofeng; Zhang, Ruibo; Fan, Zhaoyang

    2018-05-01

    With the fully exposed graphene edges, high conductivity and large surface area, edge oriented graphene foam (EOGF), prepared by deposition of perpendicular graphene network encircling the struts of Ni foam, is a superior scaffold to support active materials for electrochemical applications. With VO2 as an example, EOGF loaded VO2 nanoparticle (VO2/EOGF) electrode has high rate performance as cathode in lithium ion batteries (LIBs). In addition to the Li+ intercalation into the lattice, contribution of non-diffusion-limited pseudocapacitance to the capacity is prominent at high rates. VO2/EOGF based supercapacitor also exhibits fast response, with a characteristic frequency of 15 Hz when the phase angle reaches -45°, or a relaxation time constant of 66.7 ms. These results suggest the promising potential of EOGF as a scaffold in supporting active nanomaterials for electrochemical energy storage and other applications.

  4. Epitaxial growth and electronic structure of oxyhydride SrVO2H thin films

    Science.gov (United States)

    Katayama, Tsukasa; Chikamatsu, Akira; Yamada, Keisuke; Shigematsu, Kei; Onozuka, Tomoya; Minohara, Makoto; Kumigashira, Hiroshi; Ikenaga, Eiji; Hasegawa, Tetsuya

    2016-08-01

    Oxyhydride SrVO2H epitaxial thin films were fabricated on SrTiO3 substrates via topotactic hydridation of oxide SrVO3 films using CaH2. Structural and composition analyses suggested that the SrVO2H film possessed one-dimensionally ordered V-H--V bonds along the out-of-plane direction. The synthesis temperature could be lowered by reducing the film thickness, and the SrVO2H film was reversible to SrVO3 by oxidation through annealing in air. Photoemission and X-ray absorption spectroscopy measurements revealed the V3+ valence state in the SrVO2H film, indicating that the hydrogen existed as hydride. Furthermore, the electronic density of states was highly suppressed at the Fermi energy, consistent with the prediction that tetragonal distortion induces metal to insulation transition.

  5. Supercritical temperature synthesis of fluorine-doped VO2(M) nanoparticle with improved thermochromic property

    Science.gov (United States)

    Riapanitra, Anung; Asakura, Yusuke; Cao, Wenbin; Noda, Yasuto; Yin, Shu

    2018-06-01

    Fluorine-doped VO2(M) nanoparticles have been successfully synthesized using the hydrothermal method at a supercritical temperature of 490 °C. The pristine VO2(M) has the critical phase transformation temperature of 64 °C. The morphology and homogeneity of the monoclinic structure VO2(M) were adopted by the fluorine-doped system. The obtained particle size of the samples is smaller at the higher concentration of anion doping. The best reduction of critical temperature was achieved by fluorine doping of 0.13% up to 48 °C. The thin films of the fluorine-doped VO2(M) showed pronounced thermochromic property and therefore are suitable for smart window applications.

  6. Thermally tunable VO2-SiO2 nanocomposite thin-film capacitors

    Science.gov (United States)

    Sun, Yifei; Narayanachari, K. V. L. V.; Wan, Chenghao; Sun, Xing; Wang, Haiyan; Cooley, Kayla A.; Mohney, Suzanne E.; White, Doug; Duwel, Amy; Kats, Mikhail A.; Ramanathan, Shriram

    2018-03-01

    We present a study of co-sputtered VO2-SiO2 nanocomposite dielectric thin-film media possessing continuous temperature tunability of the dielectric constant. The smooth thermal tunability is a result of the insulator-metal transition in the VO2 inclusions dispersed within an insulating matrix. We present a detailed comparison of the dielectric characteristics of this nanocomposite with those of a VO2 control layer and of VO2/SiO2 laminate multilayers of comparable overall thickness. We demonstrated a nanocomposite capacitor that has a thermal capacitance tunability of ˜60% between 25 °C and 100 °C at 1 MHz, with low leakage current. Such thermally tunable capacitors could find potential use in applications such as sensing, thermal cloaks, and phase-change energy storage devices.

  7. EVALUATION AND DEVELOPMENT OF THE VO2 OF ATHLETES THAT ATTEND A SOCCER SCHOOL

    Directory of Open Access Journals (Sweden)

    Felipe Bittencourt Oliveira

    2012-11-01

    Full Text Available The goal of this study was to identify the effects from technical and physical activities on the VO2, of male athletes aged 14 to 15, participants of a soccer school, in the municipality of Rio Pardo - RS. The semi-experimental research involved 10 male adolescents. For the VO2 evaluation the 12 minute Cooper test was used. Interval-training work was applied, at which the athletes exercised 75% of their maximum speed, in 60-meter runs. After training for two months (at least two sessions a week the Cooper post-test was applied to check the improvement of the VO2. As results of this study, we can draw the conclusion that all adolescents involved in this training showed considerable improvement in their maximum VO2, especially the 15-year-old teens, who managed to obtain a much higher percentage level.

  8. Broadband terahertz generation using the semiconductor-metal transition in VO2

    Directory of Open Access Journals (Sweden)

    Nicholas A. Charipar

    2016-01-01

    Full Text Available We report the design, fabrication, and characterization of broadband terahertz emitters based on the semiconductor-metal transition in thin film VO2 (vanadium dioxide. With the appropriate geometry, picosecond electrical pulses are generated by illuminating 120 nm thick VO2 with 280 fs pulses from a femtosecond laser. These ultrafast electrical pulses are used to drive a simple dipole antenna, generating broadband terahertz radiation.

  9. Size and composition-controlled fabrication of VO2 nanocrystals by terminated cluster growth

    Energy Technology Data Exchange (ETDEWEB)

    Anders, Andre; Slack, Jonathan

    2013-05-14

    A physical vapor deposition-based route for the fabrication of VO2 nanoparticles is demonstrated, consisting of reactive sputtering and vapor condensation at elevated pressures. The oxidation of vanadium atoms is an efficient heterogeneous nucleation method, leading to high nanoparticle throughtput. Fine control of the nanoparticle size and composition is obtained. Post growth annealing leads to crystalline VO2 nanoparticles with optimum thermocromic and plasmonic properties.

  10. Human mitochondrial haplogroup H: the highest VO2max consumer--is it a paradox?

    Science.gov (United States)

    Martínez-Redondo, Diana; Marcuello, Ana; Casajús, José A; Ara, Ignacio; Dahmani, Yahya; Montoya, Julio; Ruiz-Pesini, Eduardo; López-Pérez, Manuel J; Díez-Sánchez, Carmen

    2010-03-01

    Mitochondrial background has been demonstrated to influence maximal oxygen uptake (VO(2max), in mLkg(-1)min(-1)), but this genetic influence can be compensated for by regular exercise. A positive correlation among electron transport chain (ETC) coupling, ATP and reactive oxygen species (ROS) production has been established, and mitochondrial variants have been reported to show differences in their ETC performance. In this study, we examined in detail the VO(2max) differences found among mitochondrial haplogroups. We recruited 81 healthy male Spanish Caucasian individuals and determined their mitochondrial haplogroup. Their VO(2max) was determined using incremental cycling exercise (ICE). VO(2max) was lower in J than in non-J haplogroup individuals (P=0.04). The H haplogroup was responsible for this difference (VO(2max); J vs. H; P=0.008) and this group also had significantly higher mitochondrial oxidative damage (mtOD) than the J haplogroup (P=0.04). In agreement with these results, VO(2max) and mtOD were positively correlated (P=0.01). Given that ROS production is the major contributor to mtOD and consumes four times more oxygen per electron than the ETC, our results strongly suggest that ROS production is responsible for the higher VO(2max) found in the H variant. These findings not only contribute to a better understanding of the mechanisms underneath VO(2max), but also help to explain some reported associations between mitochondrial haplogroups and mtOD with longevity, sperm motility, premature aging and susceptibility to different pathologies.

  11. Broadband modulation of terahertz waves through electrically driven hybrid bowtie antenna-VO2 devices.

    Science.gov (United States)

    Han, Chunrui; Parrott, Edward P J; Humbert, Georges; Crunteanu, Aurelian; Pickwell-MacPherson, Emma

    2017-10-05

    Broadband modulation of terahertz (THz) light is experimentally realized through the electrically driven metal-insulator phase transition of vanadium dioxide (VO 2 ) in hybrid metal antenna-VO 2 devices. The devices consist of VO 2 active layers and bowtie antenna arrays, such that the electrically driven phase transition can be realized by applying an external voltage between adjacent metal wires extended to a large area array. The modulation depth of the terahertz light can be initially enhanced by the metal wires on top of VO 2 and then improved through the addition of specific bowties in between the wires. As a result, a terahertz wave with a large beam size (~10 mm) can be modulated within the measurable spectral range (0.3-2.5 THz) with a frequency independent modulation depth as high as 0.9, and the minimum amplitude transmission down to 0.06. Moreover, the electrical switch on/off phase transition depends very much on the size of the VO 2 area, indicating that smaller VO 2 regions lead to higher modulation speeds and lower phase transition voltages. With the capabilities in actively tuning the beam size, modulation depth, modulation bandwidth as well as the modulation speed of THz waves, our study paves the way in implementing multifunctional components for terahertz applications.

  12. VO2 microcrystals as an advanced smart window material at semiconductor to metal transition

    Science.gov (United States)

    Basu, Raktima; Magudapathy, P.; Sardar, Manas; Pandian, Ramanathaswamy; Dhara, Sandip

    2017-11-01

    Textured VO2(0 1 1) microcrystals are grown in the monoclinic, M1 phase which undergoes a reversible first order semiconductor to metal transition (SMT) accompanied by a structural phase transition to rutile tetragonal, R phase. Around the phase transition, VO2 also experiences noticeable change in its optical and electrical properties. A change in color of the VO2 micro crystals from white to cyan around the transition temperature is observed, which is further understood by absorption of red light using temperature dependent ultraviolet-visible spectroscopic analysis and photoluminescence studies. The absorption of light in the red region is explained by the optical transition between Hubbard states, confirming the electronic correlation as the driving force for SMT in VO2. The thermochromism in VO2 has been studied for smart window applications so far in the IR region, which supports the opening of the band gap in semiconducting phase; whereas there is hardly any report in the management of visible light. The filtering of blue light along with reflection of infrared above the semiconductor to metal transition temperature make VO2 applicable as advanced smart windows for overall heat management of a closure.

  13. VO2 microcrystals as an advanced smart window material at semiconductor to metal transition

    International Nuclear Information System (INIS)

    Basu, Raktima; Pandian, Ramanathaswamy; Dhara, Sandip; Magudapathy, P; Sardar, Manas

    2017-01-01

    Textured VO 2 (0 1 1) microcrystals are grown in the monoclinic, M1 phase which undergoes a reversible first order semiconductor to metal transition (SMT) accompanied by a structural phase transition to rutile tetragonal, R phase. Around the phase transition, VO 2 also experiences noticeable change in its optical and electrical properties. A change in color of the VO 2 micro crystals from white to cyan around the transition temperature is observed, which is further understood by absorption of red light using temperature dependent ultraviolet–visible spectroscopic analysis and photoluminescence studies. The absorption of light in the red region is explained by the optical transition between Hubbard states, confirming the electronic correlation as the driving force for SMT in VO 2 . The thermochromism in VO 2 has been studied for smart window applications so far in the IR region, which supports the opening of the band gap in semiconducting phase; whereas there is hardly any report in the management of visible light. The filtering of blue light along with reflection of infrared above the semiconductor to metal transition temperature make VO 2 applicable as advanced smart windows for overall heat management of a closure. (paper)

  14. Familial aggregation of VO(2max) response to exercise training: results from the HERITAGE Family Study.

    Science.gov (United States)

    Bouchard, C; An, P; Rice, T; Skinner, J S; Wilmore, J H; Gagnon, J; Pérusse, L; Leon, A S; Rao, D C

    1999-09-01

    The aim of this study was to test the hypothesis that individual differences in the response of maximal O(2) uptake (VO(2max)) to a standardized training program are characterized by familial aggregation. A total of 481 sedentary adult Caucasians from 98 two-generation families was exercise trained for 20 wk and was tested for VO(2max) on a cycle ergometer twice before and twice after the training program. The mean increase in VO(2max) reached approximately 400 ml/min, but there was considerable heterogeneity in responsiveness, with some individuals experiencing little or no gain, whereas others gained >1.0 l/min. An ANOVA revealed that there was 2.5 times more variance between families than within families in the VO(2max) response variance. With the use of a model-fitting procedure, the most parsimonious models yielded a maximal heritability estimate of 47% for the VO(2max) response, which was adjusted for age and sex with a maternal transmission of 28% in one of the models. We conclude that the trainability of VO(2max) is highly familial and includes a significant genetic component.

  15. Relating Solar Energetic Particle Event Fluences to Peak Intensities

    Science.gov (United States)

    Kahler, Stephen W.; Ling, Alan G.

    2018-02-01

    Recently we (Kahler and Ling, Solar Phys. 292, 59, 2017: KL) have shown that time-intensity profiles [I(t)] of 14 large solar energetic particle (SEP) events can be fitted with a simple two-parameter fit, the modified Weibull function, which is characterized by shape and scaling parameters [α and β]. We now look for a simple correlation between an event peak energy intensity [Ip] and the time integral of I(t) over the event duration: the fluence [F]. We first ask how the ratio of F/Ip varies for the fits of the 14 KL events and then examine that ratio for three separate published statistical studies of SEP events in which both F and Ip were measured for comparisons of those parameters with various solar-flare and coronal mass ejection (CME) parameters. The three studies included SEP energies from a 4 - 13 MeV band to E > 100 MeV. Within each group of SEP events, we find a very robust correlation (CC > 0.90) in log-log plots of F versus Ip over four decades of Ip. The ratio increases from western to eastern longitudes. From the value of Ip for a given event, F can be estimated to within a standard deviation of a factor of {≤} 2. Log-log plots of two studies are consistent with slopes of unity, but the third study shows plot slopes of { 10 MeV to {>} 100 MeV. This difference is not explained.

  16. 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

  17. Audible thunder characteristic and the relation between peak ...

    Indian Academy of Sciences (India)

    can detect, generally a few tens of hertz. Audi- ... paper, audible thunder signals have been obtained and analysed. Thunder ... thunder data when the optical spectrum of light- ning could .... finally a relatively weak sound of long duration and.

  18. Low-level laser therapy improves the VO2 kinetics in competitive cyclists.

    Science.gov (United States)

    Lanferdini, Fábio J; Krüger, Renata L; Baroni, Bruno M; Lazzari, Caetano; Figueiredo, Pedro; Reischak-Oliveira, Alvaro; Vaz, Marco A

    2018-04-01

    Some evidence supports that low-level laser therapy (LLLT) reduces neuromuscular fatigue, so incrementing sports performance. A previous randomized controlled trial of our group showed increased exercise tolerance in male competitive cyclists treated with three different LLLT doses (3, 6, and 9 J/diode; or 135, 270, and 405 J/thigh) before time-to-exhaustion cycling tests. Now, the present study was designed to evaluate the effects of these LLLT doses on the VO 2 kinetics of athletes during cycling tests. Twenty male competitive cyclists (29 years) participated in a crossover, randomized, double-blind, and placebo-controlled trial. On the first day, the participants performed an incremental cycling test to exhaustion to determine maximal oxygen uptake (VO 2MAX ) and maximal power output (PO MAX ), as well as a familiarization with the time-to-exhaustion test. In the following days (2 to 5), all participants performed time-to-exhaustion tests at PO MAX . Before the exhaustion test, different doses of LLLT (3, 6, and 9 J/diode; or 135, 270, and 405 J/thigh, respectively) or placebo were applied bilaterally to the quadriceps muscle. All exhaustion tests were monitored online by an open-circuit spirometry system in order to analyze the VO 2 amplitude, VO 2 delay time, time constant (tau), and O 2 deficit. Tau and O 2 deficit were decreased with LLLT applications compared to the placebo condition (p  0.05) were found between the experimental conditions for VO 2 amplitude and VO 2 delay time. In conclusion, LLLT decreases tau and O 2 deficit during time-to-exhaustion tests in competitive cyclists, and these changes in VO 2 kinetics response can be one of the possible mechanisms to explain the ergogenic effect induced by LLLT.

  19. Silver Vanadium Phosphorous Oxide, Ag(2)VO(2)PO(4): Chimie Douce Preparation and Resulting Lithium Cell Electrochemistry.

    Science.gov (United States)

    Kim, Young Jin; Marschilok, Amy C; Takeuchi, Kenneth J; Takeuchi, Esther S

    2011-08-15

    Recently, we have shown silver vanadium phosphorous oxide (Ag(2)VO(2)PO(4), SVPO) to be a promising cathode material for lithium based batteries. Whereas the first reported preparation of SVPO employed an elevated pressure, hydrothermal approach, we report herein a novel ambient pressure synthesis method to prepare SVPO, where our chimie douce preparation is readily scalable and provides material with a smaller, more consistent particle size and higher surface area relative to SVPO prepared via the hydrothermal method. Lithium electrochemical cells utilizing SVPO cathodes made by our new process show improved power capability under constant current and pulse conditions over cells containing cathode from SVPO prepared via the hydrothermal method.

  20. The effect of Iron Supplying on VO2 MAX and Haematology Parameter on Menstrual Woman

    Science.gov (United States)

    Nailuvar Sinaga, Rika; Sari Harahap, Novita; Mediyana Sari, Rima

    2018-03-01

    One of the supporting factors to have good aerobic endurance requires high VO2 max levels supported by good quality and quantity level of Haematology parameter especially such as erythrocytes, hematocrit and hemoglobin. One of the components in hemoglobin is iron which functions as theoxygen transport to parts of all body required in the process of metabolism. The objective of this research was to find out the difference between VO2 Max and Haematology parameter between iron supplying and no iron supplyingonmenstrual woman. The type of this research is quasi experimental research with non-randomized control group Pretest-Postest Design. The subjectsarethe studentsat faculty of Sports Sciences, Medan State University with the criteria of female gender, monthly regular menstrual cycle, having the level of health and the level of training, willing to be a sample by filling out informed consent. The total number of research subjectsis twenty students, divided into two groups namely the treatment group and the control group. The hematology parameter was measuredby Haemotology analyzer and VO2 Max was measured by multi-stage run. The result showed that there was a significant effect of iron supplyingon the increase of erythrocyte level on menstrual women, hemotocrit, haemoglobin and an increase in VO2 Max. Iron supplying on menstrual woman has the effect on the increase of erythrocyte, hematocrit, hemoglobin level and VO2 Max

  1. Optical switching properties of VO2 films driven by using WDM-aligned lasers

    International Nuclear Information System (INIS)

    Tsai, K.Y.; Wu, F.-H.; Shieh, H.-P.D.; Chin, T.-S.

    2006-01-01

    Vanadium dioxide (VO 2 ) film had been demonstrated a high speed IR shutter driven by total optical modulation. However, it usually required a higher power heating laser of high power and precise optical systems to cover the probe beam on the sample with a heating beam of larger area. A new optical system, simply composed of wavelength division multiplexing (WDM), fiber lens or convex lens system, and a glass sheet with VO 2 thin film on it, was easily assembled to utilize VO 2 film as an IR shutter, implying the possibility to highly miniaturize the VO 2 -based optical shutter. A permanent low-transmittance (PLT) region forms on the film within the probe beam, resulting in a decrease in average power of the probe beam. Another ring-type switching area (switching ring) forms around the PLT region, resulting in the transmittance switching of the probe beam synchronously with the heating signal. VO 2 films can be switched with the highest rate of a continuous square heating signal of 3 mW at 120 kHz. A heating pulse of 0.7 ns and 13 mW can be used to stimulate an IR pulse with fiber lens

  2. Effects of erythrocyte infusion on VO2max at high altitude

    DEFF Research Database (Denmark)

    Young, Jette Feveile; Sawka, M N; Muza, S R

    1996-01-01

    This study investigated whether autologous erythrocyte infusion would ameliorate the decrement in maximal O2 uptake (VO2max) experienced by lowlanders when they ascend to high altitude. VO2max was measured in 16 men (treadmill running) at sea level (SL) and on the 1st (HA1) and 9th (HA9) days...... of high-altitude (4,300 m) residence. After VO2max was measured at SL, subjects were divided into two matched groups (n = 8). Twenty-four hours before ascent to high altitude, the experimental group received a 700-ml infusion of autologous erythrocytes and saline (42% hematocrit), whereas the control...... group received only saline. The VO2max of erythrocyte-infused [54 +/- 1 (SE) ml.kg-1.min-1] and control subjects (52 +/- 2 ml.kg-1.min-1) did not differ at SL before infusion. The decrement in VO2max on HA1 did not differ between groups, averaging 26% overall, despite higher (P

  3. Thermal coupling and effect of subharmonic synchronization in a system of two VO2 based oscillators

    Science.gov (United States)

    Velichko, Andrey; Belyaev, Maksim; Putrolaynen, Vadim; Perminov, Valentin; Pergament, Alexander

    2018-03-01

    We explore a prototype of an oscillatory neural network (ONN) based on vanadium dioxide switching devices. The model system under study represents two oscillators based on thermally coupled VO2 switches. Numerical simulation shows that the effective action radius RTC of coupling depends both on the total energy released during switching and on the average power. It is experimentally and numerically proved that the temperature change ΔT commences almost synchronously with the released power peak and T-coupling reveals itself up to a frequency of about 10 kHz. For the studied switching structure configuration, the RTC value varies over a wide range from 4 to 45 μm, depending on the external circuit capacitance C and resistance Ri, but the variation of Ri is more promising from the practical viewpoint. In the case of a "weak" coupling, synchronization is accompanied by attraction effect and decrease of the main spectra harmonics width. In the case of a "strong" coupling, the number of effects increases, synchronization can occur on subharmonics resulting in multilevel stable synchronization of two oscillators. An advanced algorithm for synchronization efficiency and subharmonic ratio calculation is proposed. It is shown that of the two oscillators the leading one is that with a higher main frequency, and, in addition, the frequency stabilization effect is observed. Also, in the case of a strong thermal coupling, the limit of the supply current parameters, for which the oscillations exist, expands by ∼10%. The obtained results have a universal character and open up a new kind of coupling in ONNs, namely, T-coupling, which allows for easy transition from 2D to 3D integration. The effect of subharmonic synchronization hold promise for application in classification and pattern recognition.

  4. Thermally tunable broadband omnidirectional and polarization-independent super absorber using phase change material VO2

    Directory of Open Access Journals (Sweden)

    Zhejun Liu

    Full Text Available In this letter, we numerically demonstrate a thermally tunable super absorber by using phase change material VO2 as absorbing layer in metal-insulator-metal structure. An omnidirectional super absorption at λ=2.56μm can be realized by heating the patterned grating VO2 film due to magnetic resonance mechanism. Furthermore, a broadband super absorption higher than 0.8 in the entire 1.6μm–4μm region is achieved when VO2 film is patterned chessboard structure and transformed to metal phase beyond transition temperature. This broadband super absorption can be fulfilled in a wide range of incident angle (0°–70° and under all polarization conditions. Keywords: Phase change material, Metal-insulator-metal, Super absorption, Magnetic resonance

  5. Tunable subwavelength hot spot of dipole nanostructure based on VO2 phase transition.

    Science.gov (United States)

    Park, Jun-Bum; Lee, Il-Min; Lee, Seung-Yeol; Kim, Kyuho; Choi, Dawoon; Song, Eui Young; Lee, Byoungho

    2013-07-01

    We propose a novel approach to generate and tune a hot spot in a dipole nanostructure of vanadium dioxide (VO2) laid on a gold (Au) substrate. By inducing a phase transition of the VO2, the spatial and spectral distributions of the hot spot generated in the feed gap of the dipole can be tuned. Our numerical simulation based on a finite-element method shows a strong intensity enhancement difference and tunability near the wavelength of 678 nm, where the hot spot shows 172-fold intensity enhancement when VO2 is in the semiconductor phase. The physical mechanisms of forming the hot spots at the two-different phases are discussed. Based on our analysis, the effects of geometric parameters in our dipole structure are investigated with an aim of enhancing the intensity and the tunability. We hope that the proposed nanostructure opens up a practical approach for the tunable near-field nano-photonic devices.

  6. Microwave assisted growth of nanorods vanadium dioxide VO2 (R): structural and electrical properties

    Science.gov (United States)

    Derkaoui, I.; Khenfouch, M.; Mothudi, B. M.; Moloi, S. J.; Zorkani, I.; Jorio, A.; Maaza, M.

    2018-03-01

    Nanostructured metal oxides have attracted a lot of attention recently owning to their unique structural advantages and demonstrated promising chemical and physical properties for various applications. In this study, we report the structural and electrical properties of vanadium dioxide VO2 (R) prepared via a single reaction microwave (SRC) synthesis. Our results are revealing that the components of VO2 (R) films have a rod-like shape with a uniform size distribution. The nanorods with very smooth and flat surfaces have a typical length of up to 2μm and a width of about several nanometers. The structural investigations reveal the high crystallinity of VO2 (R) ensuring good electrical contact and showing a high conductivity as a function of temperature. This synthesis method provides a new simple route to fabricate one-dimensional nanostructured metal oxides which is suitable for a large field of applications especially for smart windows.

  7. HEART RATE VARIABILITY AND BODY COMPOSITION AS VO2MAX DETERMINANTS

    Directory of Open Access Journals (Sweden)

    Henry Humberto León-Ariza

    Full Text Available ABSTRACT Introduction: The maximum oxygen consumption (VO2max is the gold standard in the cardiorespiratory endurance assessment. Objective: This study aimed to develop a mathematical model that contains variables to determine the VO2max of sedentary people. Methods: Twenty participants (10 men and 10 women with a mean age of 19.8±1.77 years were included. For each participant, body composition (percentage of fat and muscle, heart rate variability (HRV at rest (supine and standing, and VO2max were evaluated through an indirect test on a cycloergometer. A multivariate linear regression model was developed from the data obtained, and the model assumptions were verified. Results: Using the data obtained, including percentage of fat (F, percentage of muscle (M, percentage of power at very low frequency (VLF, α-value of the detrended fluctuation analysis (DFAα1, heart rate (HR in the resting standing position, and age of the participants, a model was established for men, which was expressed as VO2max = 4.216 + (Age*0.153 + (F*0.110 - (M*0.053 - (VLF*0.649 - (DFAα1*2.441 - (HR*0.014, with R2 = 0.965 and standard error = 0.146 L/min. For women, the model was expressed as VO2max = 1.947 - (Age*0.047 + (F*0.024 + (M*0.054 + (VLF*1.949 - (DFAα1*0.424 - (HR*0.019, with R2 = 0.987 and standard error = 0.077 L/min. Conclusion: The obtained model demonstrated the influence exerted by body composition, the autonomic nervous system, and age in the prediction of VO2max.

  8. Estimated VO2max and its corresponding velocity predict performance of amateur runners

    Directory of Open Access Journals (Sweden)

    Bruno Ribeiro Ramalho Oliveira

    2012-03-01

    Full Text Available In recent years, there has been a substantial increase in the number of runners, with a proportional increase in their involvement in amateur street competition. Identification of the determinants of performance in this population appears necessary for optimization of time devoted to training. The objective of this study was to ascertain the association between estimated maximal oxygen uptake (VO2max, critical velocity (CV and VO2max velocity (VVO2max and athletic performance in the 3.6 km (uphill and 10 and 21.1 km (flatland events. Twelve amateur runners (nine male, mean age 36 ± 5 years underwent five tests: 1 and 5 km race on level ground, 3.6 km race with slope (≈8%, and indirect VO2max measurement. CV was determined from the linear relationship between distance and run time on the first two tests. The subjects then took part in two official 10 km and 21.1 km (half marathon races. VVO2max was calculated from the VO2max through a metabolic equation. VO2max showed the best association with running performance in the 10 and 21.1 km events. For the uphill race, VVO2max showed a better association. Overall, the variable with the highest average association was VO2max (0.91±0.07, followed by VVO2max (0.90±0.04 and VC (0.87±0.06. This study showed strong associations between physiological variables established by low-cost, user-friendly indirect methods and running performance in the 10 and 21.1 km (flatland and 3.6 km (uphill running events.

  9. Gate voltage controlled humidity sensing using MOSFET of VO2 particles

    CSIR Research Space (South Africa)

    Akande, Amos A

    2017-01-01

    Full Text Available (A), VO2 (AH) [4], [5] and M2 the intermediate phase between M1 and R phase. These phases have been generally useful in technologies such as thermal switch (thermochromic window), thermal/infrared sensors, A.A Akande holds PhD studentship...) is 272.1, A1 and A2 are respectively 0.118 and 12096 with a correlation coefficient, R2, of 0.925. These results suggest that the VO2 sensor is very resilient to humidity such that it does not saturate even when humidity approaches 100%. This sensor...

  10. PENGEMBANGAN PERSAMAAN VO2 MAX DAN EVALUASI HR MAX (STUDI AWAL PADA PEKERJA PRIA

    Directory of Open Access Journals (Sweden)

    Purnawan Adi Wicaksono

    2012-10-01

    Full Text Available Kapasitas fisik maksimum seseorang direpresentasikan dengan nilai konsumsi oksigen maksimum (VO2 Max dan denyut nadi maksimum (HR Max yang memberikan suatu informasi batasan kemampuan fisik maksimum seseorang dalam melakukan pekerjaan. Penelitian kali ini mempunyai tujuan untuk mencari nilai VO2 Max pekerja pria Indonesia untuk nantinya akan dikembangkan suatu persamaan prediksi VO2 Max yang didekati dengan hubungan linier antara denyut nadi (Heart Rate seperti yang dilakukan Astrand (2003, tinggi badan (Chatterjee et al, 2006, berat badan (Akalan et al, 2008, usia (Magrani et al, 2009 dan mengevaluasi persamaan HR Max manakah yang dapat diaplikasikan untuk mendekati nilai denyut nadi maksimum pekerja Indonesia. Responden dalam penelitian kali ini adalah 12  pekerja industri pria yang diambil dari beberapa industri di Depok dan sekitarnya. Kriteria responden yang berpartisipasi dalam penelitian kali ini adalah: berusia 20-40 tahun, bukan perokok baik aktif maupun pasif, sehat , tidak mengkonsumsi makanan, kafein, alkohol minimal 2 jam sebelum eksperimen (Balderrama et. al, 2007.Eksperimen yang dilakukan menggunakan metode maximal test dengan protokol treadmill. Adapun peralatan yang digunakan adalah seperangkat alat pengukur kondisi fisiologi Fitmate MED (COSMED srl-Italy terdiri dari Heart Rate Transmitter, Heart Rate Receiver, V mask (Hans Rudolph Inc,dan treadmill SportArt@60.  Eksperimen dilakukan menjadi dua bagian, yaitu istirahat dan tahap bekerja.Aktivitas istirahat terdiri dari tidur selama 20 menit, duduk selama 20 menit dan berdiri selama 10 menit. Eksperimen tahap kedua yaitu tahap kerja yang terdiri dari latihan selama 5 menit. Responden dipersilakan beristirahat selama 15 menit, setelah itu responden melaksanakan maximal test detik hingga responden merasa tidak sanggup lagi melanjutkan eksperimen. Hasil penelitian model prediksi VO2 max untuk pekerja industri pria mempunyai nilai 2,78 ± 0,5 liter/menit dan dengan regresi linier

  11. Impact of growth temperature on the crystal habits, forms and structures of VO2 nanocrystals

    International Nuclear Information System (INIS)

    Loeffler, Stefan; Auer, Erwin; Lugstein, Alois; Bertagnolli, Emmerich; Weil, Matthias

    2011-01-01

    We investigated the impact of the process temperature on the habits, forms and crystal structure of VO 2 nanocrystals grown by a vapor-transport method on (0001) quartz substrates. Four distinct growth regimes were discerned: orthorhombic nanowires, sheets, hemispheres, and nanowires with a monoclinic structure. The nanostructures were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). I/V characterization of individual nanowires was enabled by Ti/Au contact formation via electron beam lithography and lift-off techniques. The expected metal-insulator transition (MIT) was found in monoclinic VO 2 nanowires. (orig.)

  12. Metal-insulator phase transition in a VO2 thin film observed with terahertz spectroscopy

    DEFF Research Database (Denmark)

    Jepsen, Peter Uhd; Fischer, Bernd M.; Thoman, Andreas

    2006-01-01

    We investigate the dielectric properties of a thin VO2 film in the terahertz frequency range in the vicinity of the semiconductor-metal phase transition. Phase-sensitive broadband spectroscopy in the frequency region below the phonon bands of VO2 gives insight into the conductive properties...... of the film during the phase transition. We compare our experimental data with models proposed for the evolution of the phase transition. The experimental data show that the phase transition occurs via the gradual growth of metallic domains in the film, and that the dielectric properties of the film...

  13. Thermochromic VO2 thin films deposited by magnetron sputtering for smart window applications

    Science.gov (United States)

    Fortier, Jean-Philippe

    "Smart" windows are a perfect innovative example of technology that reduces our energy dependence and our impact on the environment while saving on the economical point of view. With the use of vanadium dioxide (VO2), a thermochromic compound, and this, as a thin coating, it would in fact be possible to control the sun's transmission of infrared light (heat) as a function of the surrounding environment temperature. In other words, its optical behavior would allow a more effective management of heat exchanges between a living venue and the outdoor environment. However, this type of window is still in a developmental stage. First, the oxide's deposition is not simple in nature. Based on a conventional deposition technique called magnetron sputtering mainly used in the fenestration industry, several factors such as the oxygen concentration and the substrate temperature during deposition can affect the coating's thermochromic behavior, and this, by changing its composition and crystallinity. Other control parameters such as the deposition rate, the pressure in the sputtering chamber and the choice of substrate may also modify the film microstructure, thereby varying its optical and electrical properties. In addition, several issues still persist as to its commercial application. For starters, the material's structural transition, related to the change of its optical properties, only occurs around 68°C. In addition, its low transparency and natural greenish colour are not visually appealing. Then, to this day, the deposition temperature required to crystallize and form the thermochromic oxide remains an obstacle for a possible large-scale application. Ultimately, although the material's change in temperature has been shown to be advantageous in situations of varying climate, the existing corrective solutions to these issues generate a deterioration of the thermochromic behavior. With no practical expertise on the material, this project was undertaken with certain

  14. Interpretation of the peak areas in gamma-ray spectra that have a large relative uncertainty

    International Nuclear Information System (INIS)

    Korun, M.; Maver Modec, P.; Vodenik, B.

    2012-01-01

    Empirical evidence is provided that the areas of peaks having a relative uncertainty in excess of 30% are overestimated. This systematic influence is of a statistical nature and originates in way the peak-analyzing routine recognizes the small peaks. It is not easy to detect this influence since it is smaller than the peak-area uncertainty. However, the systematic influence can be revealed in repeated measurements under the same experimental conditions, e.g., in background measurements. To evaluate the systematic influence, background measurements were analyzed with the peak-analyzing procedure described by Korun et al. (2008). The magnitude of the influence depends on the relative uncertainty of the peak area and may amount, in the conditions used in the peak analysis, to a factor of 5 at relative uncertainties exceeding 60%. From the measurements, the probability for type-II errors, as a function of the relative uncertainty of the peak area, was extracted. This probability is near zero below an uncertainty of 30% and rises to 90% at uncertainties exceeding 50%. - Highlights: ► A systematic influence affecting small peak areas in gamma-ray spectra is described. ► The influence originates in the peak locating procedure, using a pre-determined sensitivity. ► The predetermined sensitivity makes peak areas with large uncertainties to be overestimated. ► The influence depends on the relative uncertainty of the number of counts in the peak. ► Corrections exceeding a factor of 3 are attained at peak area uncertainties exceeding 60%.

  15. VO2 OFF TRANSIENT KINETICS IN EXTREME INTENSITY SWIMMING

    Directory of Open Access Journals (Sweden)

    Ana Sousa

    2011-09-01

    Full Text Available Inconsistencies about dynamic asymmetry between the on- and off- transient responses in oxygen uptake are found in the literature. Therefore, the purpose of this study was to characterize the oxygen uptake off-transient kinetics during a maximal 200-m front crawl effort, as examining the degree to which the on/off regularity of the oxygen uptake kinetics response was preserved. Eight high level male swimmers performed a 200-m front crawl at maximal speed during which oxygen uptake was directly measured through breath-by-breath oxymetry (averaged every 5 s. This apparatus was connected to the swimmer by a low hydrodynamic resistance respiratory snorkel and valve system. Results: The on- and off-transient phases were symmetrical in shape (mirror image once they were adequately fitted by a single-exponential regression models, and no slow component for the oxygen uptake response was developed. Mean (± SD peak oxygen uptake was 69.0 (± 6.3 mL·kg-1·min-1, significantly correlated with time constant of the off- transient period (r = 0.76, p < 0.05 but not with any of the other oxygen off-transient kinetic parameters studied. A direct relationship between time constant of the off-transient period and mean swimming speed of the 200-m (r = 0.77, p < 0.05, and with the amplitude of the fast component of the effort period (r = 0.72, p < 0.05 were observed. The mean amplitude and time constant of the off-transient period values were significantly greater than the respective on- transient. In conclusion, although an asymmetry between the on- and off kinetic parameters was verified, both the 200-m effort and the respectively recovery period were better characterized by a single exponential regression model

  16. 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.

  17. Peak broadening in paper chromatography and related techniques : III. Peak broadening in thin-layer chromatography on cellulose powder

    NARCIS (Netherlands)

    Ligny, C.L. de; Remijnse, A.G.

    1968-01-01

    The mechanism of peak broadening in thin-layer chromatography on cellulose powder was investigated by comparing the peak widths obtained in chromatography with those caused only by diffusion in the cellulose powder, for a set of amino acids of widely differing RF values and six kinds of cellulose

  18. VV and VO2 defects in silicon studied with hybrid density functional theory

    KAUST Repository

    Christopoulos, Stavros Richard G; Wang, Hao; Chroneos, Alexander I.; Londos, Charalampos A.; Sgourou, Efstratia N.; Schwingenschlö gl, Udo

    2014-01-01

    The formation of VO (A-center), VV and VO2 defects in irradiated Czochralski-grown silicon (Si) is of technological importance. Recent theoretical studies have examined the formation and charge states of the A-center in detail. Here we use density

  19. Femtosecond Near Edge X-ray Absorption Measurement of the VO2 Phase Transition

    International Nuclear Information System (INIS)

    Cavalleri, A.; Chong, H.H.W.; Fourmaux, S.; Glover, T.E.; Heimann, P.A; Kieffer, J.C.; Padmore, H.A.; Schoenlein, R.W.

    2004-01-01

    The authors measure the insulator-to-metal transition in VO 2 using femtosecond Near-Edge X-ray Absorption. Sliced pulses of synchrotron radiation are used to detect the photo-induced dynamics at the 516-eV Vanadium L 3 edge

  20. Hydrothermal route to VO2 (B) nanorods: controlled synthesis and characterization

    Science.gov (United States)

    Song, Shaokun; Huang, Qiwei; Zhu, Wanting

    2017-10-01

    One-dimensional vanadium dioxides have attracted intensive attention owing to their distinctive structure and novel applications in catalysis, high energy lithium-ion batteries, chemical sensors/actuators and electrochemical devices etc. In this paper, large-scale VO2 (B) nanorods have been successfully synthesized via a versatile and environment friendly hydrothermal strategy using V2O5 as vanadium source and carbohydrates/alcohols as reductant. The obtained samples are characterized by XRD, FT-IR, TEM, and XPS techniques to investigate the effects of chemical parameters such as reductants, temperature, and time of synthesis on the structure and morphology of products. Results show that pure B phase VO2 with homogeneous nanorod-like morphology can be prepared easily at 180 °C for 3 days with glycerol as reluctant. Typically, the nanorod-like products are 0.5-1 μm long and 50 nm width. Furthermore, it is also confirmed that the products are consisted of VO2, corresponding to the B phase. More importantly, this novel approach is efficient, free of any harmful solvents and surfactants. Therefore, this efficient, green, and cost-saving route will have great potential in the large-scale fabrication of 1D VO2 (B) nanorods from the economic and environmental point of view.

  1. Metal-Insulator Phase Transition in Quasi-One-Dimensional VO2 Structures

    Directory of Open Access Journals (Sweden)

    Woong-Ki Hong

    2015-01-01

    Full Text Available The metal-insulator transition (MIT in strongly correlated oxides has attracted considerable attention from both theoretical and experimental researchers. Among the strongly correlated oxides, vanadium dioxide (VO2 has been extensively studied in the last decade because of a sharp, reversible change in its optical, electrical, and magnetic properties at approximately 341 K, which would be possible and promising to develop functional devices with advanced technology by utilizing MITs. However, taking the step towards successful commercialization requires the comprehensive understanding of MIT mechanisms, enabling us to manipulate the nature of transitions. In this regard, recently, quasi-one-dimensional (quasi-1D VO2 structures have been intensively investigated due to their attractive geometry and unique physical properties to observe new aspects of transitions compared with their bulk counterparts. Thus, in this review, we will address recent research progress in the development of various approaches for the modification of MITs in quasi-1D VO2 structures. Furthermore, we will review recent studies on realizing novel functional devices based on quasi-1D VO2 structures for a wide range of applications, such as a gas sensor, a flexible strain sensor, an electrical switch, a thermal memory, and a nonvolatile electrical memory with multiple resistance.

  2. Characteristics of the Current-Controlled Phase Transition of VO2 Microwires for Hybrid Optoelectronic Devices

    Directory of Open Access Journals (Sweden)

    Arash Joushaghani

    2015-08-01

    Full Text Available The optical and electrical characteristics of the insulator-metal phase transition of vanadium dioxide (VO2 enable the realization of power-efficient, miniaturized hybrid optoelectronic devices. This work studies the current-controlled, two-step insulator-metal phase transition of VO2 in varying microwire geometries. Geometry-dependent scaling trends extracted from current-voltage measurements show that the first step induced by carrier injection is delocalized over the microwire, while the second, thermally-induced step is localized to a filament about 1 to 2 μm wide for 100 nm-thick sputtered VO2 films on SiO2. These effects are confirmed by direct infrared imaging, which also measures the change in optical absorption in the two steps. The difference between the threshold currents of the two steps increases as the microwires are narrowed. Micron- and sub-micron-wide VO2 structures can be used to separate the two phase transition steps in photonic and electronic devices.

  3. Ultrafast electron-lattice coupling dynamics in VO2 and V2O3 thin films

    Science.gov (United States)

    Abreu, Elsa; Gilbert Corder, Stephanie N.; Yun, Sun Jin; Wang, Siming; Ramírez, Juan Gabriel; West, Kevin; Zhang, Jingdi; Kittiwatanakul, Salinporn; Schuller, Ivan K.; Lu, Jiwei; Wolf, Stuart A.; Kim, Hyun-Tak; Liu, Mengkun; Averitt, Richard D.

    2017-09-01

    Ultrafast optical pump-optical probe and optical pump-terahertz probe spectroscopy were performed on vanadium dioxide (VO2) and vanadium sesquioxide (V2O3 ) thin films over a wide temperature range. A comparison of the experimental data from these two different techniques and two different vanadium oxides, in particular a comparison of the spectral weight oscillations generated by the photoinduced longitudinal acoustic modulation, reveals the strong electron-phonon coupling that exists in both materials. The low-energy Drude response of V2O3 appears more amenable than VO2 to ultrafast strain control. Additionally, our results provide a measurement of the temperature dependence of the sound velocity in both systems, revealing a four- to fivefold increase in VO2 and a three- to fivefold increase in V2O3 across the insulator-to-metal phase transition. Our data also confirm observations of strong damping and phonon anharmonicity in the metallic phase of VO2, and suggest that a similar phenomenon might be at play in the metallic phase of V2O3 . More generally, our simple table-top approach provides relevant and detailed information about dynamical lattice properties of vanadium oxides, paving the way to similar studies in other complex materials.

  4. Adhesion characteristics of VO2 ink film sintered by intense pulsed light for smart window

    Science.gov (United States)

    Youn, Ji Won; Lee, Seok-Jae; Kim, Kwang-Seok; Kim, Dae Up

    2018-05-01

    Progress in the development of energy-efficient coatings on glass has led to the research of smart windows that can modulate solar energy in response to an external stimulus like light, heat, or electricity. Thermochromic smart windows have attracted great interest because they provide highly visible transparency and intelligently controllable solar heat. VO2 has been widely used as coating material for thermochromism owing to its reversible metal-to-insulator transition near room temperature. However, unstable crystalline phases and expensive fabrication processes of VO2 films limit their facile application in smart windows. To overcome these restrictions, we manufactured nanoinks based on VO2 nanoparticles and fabricated films using spin coating and intense pulsed light (IPL) sintering on a quartz substrate. We examined adhesion between the VO2 nanoink films and the quartz substrate by varying the applied voltages and the number of pulses. The average adhesion of thin films increased to 83 and 108 N/m as the applied voltage during IPL sintering increased from 1400 to 2000 V. By increasing the number of pulses from 5 to 20, the adhesive strength increased from 83 to 94 N/m at 1400 V, and decreased from 108 to 96 N/m at 2000 V voltage.

  5. VO2-based radiative thermal transistor with a semi-transparent base

    Science.gov (United States)

    Prod'homme, Hugo; Ordonez-Miranda, Jose; Ezzahri, Younès; Drévillon, Jérémie; Joulain, Karl

    2018-05-01

    We study a radiative thermal transistor analogous to an electronic one made of a VO2 base placed between two silica semi-infinite plates playing the roles of the transistor collector and emitter. The fact that VO2 exhibits an insulator to metal transition is exploited to modulate and/or amplify heat fluxes between the emitter and the collector, by applying a thermal current on the VO2 base. We extend the work of precedent studies considering the case where the base can be semi-transparent so that heat can be exchanged directly between the collector and the emitter. Both near and far field cases are considered leading to 4 typical regimes resulting from the fact that the emitter-base and base-collector separation distances can be larger or smaller than the thermal wavelength for a VO2 layer opaque or semi-transparent. Thermal currents variations with the base temperatures are calculated and analyzed. It is found that the transistor can operate in an amplification mode as already stated in [1] or in a switching mode as seen in [2]. An optimum configuration for the base thickness and separation distance maximizing the thermal transistor modulation factor is found.

  6. Influence of nitrate supplementation on VO(2) kinetics and endurance of elite cyclists

    DEFF Research Database (Denmark)

    Christensen, Peter Møller; Nyberg, Michael Permin; Bangsbo, Jens

    2013-01-01

    The present study examined if an elevated nitrate intake would improve VO(2) kinetics, endurance, and repeated sprint capacity in elite endurance athletes. Ten highly trained cyclists (72¿±¿4¿mL O(2) /kg/min, mean¿±¿standard deviation) underwent testing for VO(2) kinetics (3¿×¿6¿min at 298¿±¿28¿W...... juice. Plasma NOx (nitrate¿+¿nitrite) levels were higher (P¿......The present study examined if an elevated nitrate intake would improve VO(2) kinetics, endurance, and repeated sprint capacity in elite endurance athletes. Ten highly trained cyclists (72¿±¿4¿mL O(2) /kg/min, mean¿±¿standard deviation) underwent testing for VO(2) kinetics (3¿×¿6¿min at 298¿±¿28¿W......), endurance (120¿min preload followed by a 400-kcal time trial), and repeated sprint capacity (6¿×¿20¿s sprints, recovery 100¿s) during two 6-day periods in randomized order with a daily ingestion of either 0.5¿L beetroot (BR) juice to increase nitrate levels or a 0.5¿L placebo (PLA) drink with blackcurrant...

  7. Gate-tunable gigantic changes in lattice parameters and optical properties in VO2

    Science.gov (United States)

    Nakano, Masaki; Okuyama, Daisuke; Shibuya, Keisuke; Ogawa, Naoki; Hatano, Takafumi; Kawasaki, Masashi; Arima, Taka-Hisa; Iwasa, Yoshihiro; Tokura, Yoshinori

    2014-03-01

    The field-effect transistor provides an electrical switching function of current flowing through a channel surface by external gate voltage (VG). We recently reported that an electric-double-layer transistor (EDLT) based on vanadium dioxide (VO2) enables electrical switching of the metal-insulator phase transition, where the low-temperature insulating state can be completely switched to the metallic state by application of VG. Here we demonstrate that VO2-EDLT enables electrical switching of lattice parameters and optical properties as well as electrical current. We performed in-situ x-ray diffraction and optical transmission spectroscopy measurements, and found that the c-axis length and the infrared transmittance of VO2 can be significantly modulated by more than 1% and 40%, respectively, by application of VG. We emphasize that these distinguished features originate from the electric-field induced bulk phase transition available with VO2-EDLT. This work was supported by the Japan Society for the Promotion of Science (JSPS) through its ``Funding Program for World-Leading Innovative R&D on Science and Technology (FIRST Program).''

  8. Surface charge sensing by altering the phase transition in VO2

    Science.gov (United States)

    Kumar, S.; Esfandyarpour, R.; Davis, R.; Nishi, Y.

    2014-08-01

    Detection of surface charges has various applications in medicine, electronics, biotechnology, etc. The source of surface charge induction may range from simple charge-polarized molecules like water to complicated proteins. It was recently discovered that surface charge accumulation can alter the temperature at which VO2 undergoes a Mott transition. Here, we deposited polar molecules onto the surface of two-terminal thin-film VO2 lateral devices and monitored the joule-heating-driven Mott transition, or conductance switching. We observed that the power required to induce the conductance switching reduced upon treatment with polar molecules and, using in-situ blackbody-emission direct measurement of local temperature, we show that this reduction in power was accompanied by reduction in the Mott transition temperature. Further evidence suggested that this effect has specificity to the nature of the species used to induce surface charges. Using x-ray absorption spectroscopy, we also show that there is no detectable change in oxidation state of vanadium or structural phase in the bulk of the 40 nm VO2 thin-film even as the phase transition temperature is reduced by up to 20 K by the polar molecules. The ability to alter the phase transition parameters by depositing polar molecules suggests a potential application in sensing surface charges of different origins and this set of results also highlights interesting aspects of the phase transition in VO2.

  9. Metal-semiconductor phase transition of order arrays of VO2 nanocrystals

    Science.gov (United States)

    Lopez, Rene; Suh, Jae; Feldman, Leonard; Haglund, Richard

    2004-03-01

    The study of solid-state phase transitions at nanometer length scales provides new insights into the effects of material size on the mechanisms of structural transformations. Such research also opens the door to new applications, either because materials properties are modified as a function of particle size, or because the nanoparticles interact with a surrounding matrix material, or with each other. In this paper, we describe the formation of vanadium dioxide nanoparticles in silicon substrates by pulsed laser deposition of ion beam lithographically selected sites and thermal processing. We observe the collective behavior of 50 nm diameter VO2 oblate nanoparticles, 10 nm high, and ordered in square arrays with arbitrary lattice constant. The metal-semiconductor-transition of the VO2 precipitates shows different features in each lattice spacing substrate. The materials are characterized by electron microscopy, x-ray diffraction, Rutherford backscattering. The features of the phase transition are studied via infrared optical spectroscopy. Of particular interest are the enhanced scattering and the surface plasmon resonance when the particles reach the metallic state. This resonance amplifies the optical contrast in the range of near-infrared optical communication wavelengths and it is altered by the particle-particle coupling as in the case of noble metals. In addition the VO2 nanoparticles exhibit sharp transitions with up to 50 K of hysteresis, one of the largest values ever reported for this transition. The optical properties of the VO2 nanoarrays are correlated with the size of the precipitates and their inter-particle distance. Nonlinear and ultra fast optical measurements have shown that the transition is the fastest known solid-solid transformation. The VO2 nanoparticles show the same bulk property, transforming in times shorter than 150 fs. This makes them remarkable candidates for ultrafast optical and electronic switching applications.

  10. A comparison of VO2max and metabolic variables between treadmill running and treadmill skating.

    Science.gov (United States)

    Koepp, Kriston K; Janot, Jeffrey M

    2008-03-01

    The purpose of this study was to determine differences in VO2max and metabolic variables between treadmill running and treadmill skating. This study also examined VO2max responses during a continuous skating treadmill protocol and a discontinuous skating treadmill protocol. Sixteen male high school hockey players, who had a mean age of 16 +/- 1 years and were of an above-average fitness level, participated in this study. All subjects completed 4 exercise trials: a 1-hour skating treadmill familiarization trial, a treadmill running trial, and 2 randomized skating treadmill trials. Minute ventilation (VE), oxygen consumption VO2), carbon dioxide production VCO2), respiratory exchange ratio (RER), and heart rate were averaged every 15 seconds up to VO2max for each exercise test. The results showed that there was a significant difference (P skating treadmill protocol. There was also a significant difference for maximal RER between the discontinuous and continuous skating treadmill protocol and between the discontinuous skating treadmill protocol and running treadmill protocol. In conclusion, the running treadmill elicited a greater VO2max (mL.kg.min) than the skating treadmill did, but when it comes to specificity of ice skating, the skating treadmill may be ideal. Also, there was no significant difference between the discontinuous and continuous skating treadmill protocols. Therefore, a continuous protocol is possible on the skating treadmill without compromising correct skating position and physiologic responses. However, the continuous skating treadmill protocol should undergo validation before other scientists, coaches, and strength and conditioning professionals can apply it correctly.

  11. Peak Exercise Oxygen Uptake Predicts Recurrent Admissions in Heart Failure With Preserved Ejection Fraction.

    Science.gov (United States)

    Palau, Patricia; Domínguez, Eloy; Núñez, Eduardo; Ramón, José María; López, Laura; Melero, Joana; Sanchis, Juan; Bellver, Alejandro; Santas, Enrique; Bayes-Genis, Antoni; Chorro, Francisco J; Núñez, Julio

    2018-04-01

    Heart failure with preserved ejection fraction (HFpEF) is a highly prevalent syndrome with an elevated risk of morbidity and mortality. To date, there is scarce evidence on the role of peak exercise oxygen uptake (peak VO 2 ) for predicting the morbidity burden in HFpEF. We sought to evaluate the association between peak VO 2 and the risk of recurrent hospitalizations in patients with HFpEF. A total of 74 stable symptomatic patients with HFpEF underwent a cardiopulmonary exercise test between June 2012 and May 2016. A negative binomial regression method was used to determine the association between the percentage of predicted peak VO 2 (pp-peak VO 2 ) and recurrent hospitalizations. Risk estimates are reported as incidence rate ratios. The mean age was 72.5 ± 9.1 years, 53% were women, and all patients were in New York Heart Association functional class II to III. Mean peak VO 2 and median pp-peak VO 2 were 10 ± 2.8mL/min/kg and 60% (range, 47-67), respectively. During a median follow-up of 276 days [interquartile range, 153-1231], 84 all-cause hospitalizations in 31 patients (41.9%) were registered. A total of 15 (20.3%) deaths were also recorded. On multivariate analysis, accounting for mortality as a terminal event, pp-peak VO 2 was independently and linearly associated with the risk of recurrent admission. Thus, and modeled as continuous, a 10% decrease of pp-peak VO 2 increased the risk of recurrent hospitalizations by 32% (IRR, 1.32; 95%CI, 1.03-1.68; P = .028). In symptomatic elderly patients with HFpEF, pp-peak VO 2 predicts all-cause recurrent admission. Copyright © 2017 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  12. Relative workload determines exercise-induced increases in PGC-1alpha mRNA

    DEFF Research Database (Denmark)

    Nordsborg, Nikolai Baastrup; Lundby, Carsten; Leick, Lotte

    2010-01-01

    INTRODUCTION:: The hypothesis that brief intermittent exercise induced increases in human skeletal muscle metabolic mRNA is dependent on relative workload was investigated. METHODS:: Trained (n=10) and untrained (n=8) subjects performed exhaustive intermittent cycling exercise (4x4 min @ 85% of VO2...... peak, interspersed by 3 min). Trained subjects also performed the intermittent exercise at the same absolute workload as untrained, corresponding to 70% of VO2 peak (n=6). RESULTS:: Exercise at 85% of VO2 peak elevated (P... and untrained, respectively. PGC-1alpha mRNA expression was increased (Pelevated (3.1+/-0.7 mM) and PGC-1alpha mRNA content was less (P

  13. Hydrothermal Synthesis of VO2 Polymorphs: Advantages, Challenges and Prospects for the Application of Energy Efficient Smart Windows.

    Science.gov (United States)

    Li, Ming; Magdassi, Shlomo; Gao, Yanfeng; Long, Yi

    2017-09-01

    Vanadium dioxide (VO 2 ) is a widely studied inorganic phase change material, which has a reversible phase transition from semiconducting monoclinic to metallic rutile phase at a critical temperature of τ c ≈ 68 °C. The abrupt decrease of infrared transmittance in the metallic phase makes VO 2 a potential candidate for thermochromic energy efficient windows to cut down building energy consumption. However, there are three long-standing issues that hindered its application in energy efficient windows: high τ c , low luminous transmittance (T lum ), and undesirable solar modulation ability (ΔT sol ). Many approaches, including nano-thermochromism, porous films, biomimetic surface reconstruction, gridded structures, antireflective overcoatings, etc, have been proposed to tackle these issues. The first approach-nano-thermochromism-which is to integrate VO 2 nanoparticles in a transparent matrix, outperforms the rest; while the thermochromic performance is determined by particle size, stoichiometry, and crystallinity. A hydrothermal method is the most common method to fabricate high-quality VO 2 nanoparticles, and has its own advantages of large-scale synthesis and precise phase control of VO 2 . This Review focuses on hydrothermal synthesis, physical properties of VO 2 polymorphs, and their transformation to thermochromic VO 2 (M), and discusses the advantages, challenges, and prospects of VO 2 (M) in energy-efficient smart windows application. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Synthesis of vanadium oxides 5 wt.%VO2–MxOy by sol–gel process ...

    Indian Academy of Sciences (India)

    Experimental results indicated that the VO2–SiO2 catalysts .... crucible, which was supported by the beam of a balance in the oven. ... Epoxidation of cyclohexene on VO2–Mx Oy (M = Si, Al, Ti). 1189 ... tially amorphous nature of silica.

  15. Graphene-Nanowall-Decorated Carbon Felt with Excellent Electrochemical Activity Toward VO2+/VO2+ Couple for All Vanadium Redox Flow Battery.

    Science.gov (United States)

    Li, Wenyue; Zhang, Zhenyu; Tang, Yongbing; Bian, Haidong; Ng, Tsz-Wai; Zhang, Wenjun; Lee, Chun-Sing

    2016-04-01

    3D graphene-nanowall-decorated carbon felts (CF) are synthesized via an in situ microwave plasma enhanced chemical vapor deposition method and used as positive electrode for vanadium redox flow battery (VRFB). The carbon fibers in CF are successfully wrapped by vertically grown graphene nanowalls, which not only increase the electrode specific area, but also expose a high density of sharp graphene edges with good catalytic activities to the vanadium ions. As a result, the VRFB with this novel electrode shows three times higher reaction rate toward VO 2 + /VO 2+ redox couple and 11% increased energy efficiency over VRFB with an unmodified CF electrode. Moreover, this designed architecture shows excellent stability in the battery operation. After 100 charging-discharging cycles, the electrode not only shows no observable morphology change, it can also be reused in another battery and practical with the same performance. It is believed that this novel structure including the synthesis procedure will provide a new developing direction for the VRFB electrode.

  16. Synthesis of boron and nitrogen co-doped carbon nanofiber as efficient metal-free electrocatalyst for the VO"2"+/VO_2"+ Redox Reaction

    International Nuclear Information System (INIS)

    Shi, Lang; Liu, Suqin; He, Zhen; Yuan, Hao; Shen, Junxi

    2015-01-01

    Boron or nitrogen mono-doped carbon nanofiber (CNF), and boron, nitrogen co-doped CNF are intentionally prepared as positive electrodes in a vanadium redox flow battery (VRFB). The structures and electrochemical properties of the materials are investigated by Scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, cyclic voltammetry and electrochemical impendence spectroscopy. The experimental results indicate that either B or N mono-doped CNF shown better electrochemical performance than untreated one. Interestingly, for the B and N co-doped CNF, the separated case exhibited an outstanding electrochemical activity better than either B or N mono-doped case, while the bonded case leading to a sharp drop in conductivity and shown poor electrochemical performances. These results demonstrated that not the total amount of incorporated B and N but how the B and N are incorporated into carbon nanostructures determines the catalytic activity toward VO"2"+/VO_2"+ reaction. Moreover, the individual mechanism of the nitrogen and boron containing functional groups act as active sites have been analyzed.

  17. Graphene‐Nanowall‐Decorated Carbon Felt with Excellent Electrochemical Activity Toward VO2 +/VO2+ Couple for All Vanadium Redox Flow Battery

    Science.gov (United States)

    Li, Wenyue; Zhang, Zhenyu; Bian, Haidong; Ng, Tsz‐Wai

    2015-01-01

    3D graphene‐nanowall‐decorated carbon felts (CF) are synthesized via an in situ microwave plasma enhanced chemical vapor deposition method and used as positive electrode for vanadium redox flow battery (VRFB). The carbon fibers in CF are successfully wrapped by vertically grown graphene nanowalls, which not only increase the electrode specific area, but also expose a high density of sharp graphene edges with good catalytic activities to the vanadium ions. As a result, the VRFB with this novel electrode shows three times higher reaction rate toward VO2 +/VO2+ redox couple and 11% increased energy efficiency over VRFB with an unmodified CF electrode. Moreover, this designed architecture shows excellent stability in the battery operation. After 100 charging–discharging cycles, the electrode not only shows no observable morphology change, it can also be reused in another battery and practical with the same performance. It is believed that this novel structure including the synthesis procedure will provide a new developing direction for the VRFB electrode. PMID:27774399

  18. Anomalous optical switching and thermal hysteresis during semiconductor-metal phase transition of VO2 films on Si substrate

    International Nuclear Information System (INIS)

    Leahu, G.; Li Voti, R.; Sibilia, C.; Bertolotti, M.

    2013-01-01

    We present a detailed infrared study of the semiconductor-to-metal transition (SMT) in a vanadium dioxide (VO 2 ) film deposited on silicon wafer. The VO 2 phase transition is studied in the mid-infrared region by analyzing the transmittance and the reflectance measurements, and the calculated emissivity. The reflectance has been measured in two configurations: from the side of the VO 2 film and from that of Si wafer. The results show a strong asymmetry between the emissivity in the two configurations, and the fact that the emissivity dynamic range from the silicon side is twice as large than that from the VO 2 side. The temperature behaviour of the emissivity during the SMT put into evidence the phenomenon of the anomalous absorption in VO 2 , which has been explained by applying the Maxwell Garnett effective medium approximation theory

  19. Exercise-induced prostacyclin release positively correlates with VO(2max) in young healthy men.

    Science.gov (United States)

    Zoladz, J A; Majerczak, J; Duda, K; Chłopicki, S

    2009-01-01

    In this study we have evaluated the effect of maximal incremental cycling exercise (IE) on the systemic release of prostacyclin (PGI(2)), assessed as plasma 6-keto-PGF(1alpha) concentration in young healthy men. Eleven physically active - untrained men (mean +/- S.D.) aged 22.7 +/- 2.1 years; body mass 76.3 +/- 9.1 kg; BMI 23.30 +/- 2.18 kg . m(-2); maximal oxygen uptake (VO(2max)) 46.5 +/- 3.9 ml . kg(-1) . min(-1), performed an IE test until exhaustion. Plasma concentrations of 6-keto-PGF(1alpha), lactate, and cytokines were measured in venous blood samples taken prior to the exercise and at the exhaustion. The net exercise-induced increase in 6-keto-PGF(1alpha) concentration, expressed as the difference between the end-exercise minus pre-exercise concentration positively correlated with VO(2max) (r=0.78, p=0.004) as well as with the net VO(2) increase at exhaustion (r=0.81, p=0.003), but not with other respiratory, cardiac, metabolic or inflammatory parameters of the exercise (minute ventilation, heart rate, plasma lactate, IL-6 or TNF-alpha concentrations). The exercise-induced increase in 6-keto-PGF(1alpha) concentration?? was significantly higher (p=0.008) in a group of subjects (n=5) with the highest VO(2max) when compared to the group of subjects with the lowest VO(2max), in which no increase in 6-keto-PGF(1alpha) concentration was found. In conclusion, we demonstrated, to our knowledge for the first time, that exercise-induced release of PGI(2) in young healthy men correlates with VO(2max), suggesting that vascular capacity to release PGI(2) in response to physical exercise represents an important factor characterizing exercise tolerance. Moreover, we postulate that the impairment of exercise-induced release of PGI(2) leads to the increased cardiovascular hazard of vigorous exercise.

  20. Increases in .VO2max with "live high-train low" altitude training: role of ventilatory acclimatization.

    Science.gov (United States)

    Wilhite, Daniel P; Mickleborough, Timothy D; Laymon, Abigail S; Chapman, Robert F

    2013-02-01

    The purpose of this study was to estimate the percentage of the increase in whole body maximal oxygen consumption (.VO(2max)) that is accounted for by increased respiratory muscle oxygen uptake after altitude training. Six elite male distance runners (.VO(2max) = 70.6 ± 4.5 ml kg(-1) min(-1)) and one elite female distance runner (.VO(2max)) = 64.7 ml kg(-1) min(-1)) completed a 28-day "live high-train low" training intervention (living elevation, 2,150 m). Before and after altitude training, subjects ran at three submaximal speeds, and during a separate session, performed a graded exercise test to exhaustion. A regression equation derived from published data was used to estimate respiratory muscle .VO(2) (.VO(2RM)) using our ventilation (.VE) values. .VO(2RM) was also estimated retrospectively from a larger group of distance runners (n = 22). .VO(2max) significantly (p altitude (196 ± 59 ml min(-1)), while (.VE) at .VO(2max) also significantly (p altitude (201 ± 36 ml min(-1)), along with a 10.8 ± 2.1 l min(-1) increase in (.VE), thus requiring an estimated 27 % of Δ .VO(2max) Our data suggest that a substantial portion of the improvement in .VO(2max) with chronic altitude training goes to fuel the respiratory muscles as opposed to the musculature which directly contributes to locomotion. Consequently, the time-course of decay in ventilatory acclimatization following return to sea-level may have an impact on competitive performance.

  1. Relationship between running kinematic changes and time limit at vVO2max. DOI: http://dx.doi.org/10.5007/1980-0037.2012v14n4p428

    Directory of Open Access Journals (Sweden)

    Sebastião Iberes Lopes Melo

    2012-07-01

    Full Text Available DOI: http://dx.doi.org/10.5007/1980-0037.2012v14n4p428Exhaustive running at maximal oxygen uptake velocity (vVO2max can alter running kinematic parameters and increase energy cost along the time. The aims of the present study were to compare characteristics of ankle and knee kinematics during running at vVO2max and to verify the relationship between changes in kinematic variables and time limit (Tlim. Eleven male volunteers, recreational players of team sports, performed an incremental running test until volitional exhaustion to determine vVO2max and a constant velocity test at vVO2max. Subjects were filmed continuously from the left sagittal plane at 210 Hz for further kinematic analysis. The maximal plantar flexion during swing (p<0.01 was the only variable that increased significantly from beginning to end of the run. Increase in ankle angle at contact was the only variable related to Tlim (r=0.64; p=0.035 and explained 34% of the performance in the test. These findings suggest that the individuals under study maintained a stable running style at vVO2max and that increase in plantar flexion explained the performance in this test when it was applied in non-runners.

  2. Morphology-control of VO2 (B) nanostructures in hydrothermal synthesis and their field emission properties

    International Nuclear Information System (INIS)

    Yin Haihong; Yu Ke; Zhang Zhengli; Zhu Ziqiang

    2011-01-01

    VO 2 (B) nanostructures were synthesized via a facile hydrothermal process using V 2 O 5 as source material and oxalic acid as reductant. Three nanostructures of nanorods, nanocarambolas and nanobundles were found existing in the products, and a continuous changing of morphology was found in the synthesis process, during which the proportion of these three types of nanostructures can be adjusted by altering the concentrations of oxalic acid. The microstructures were evaluated using X-ray diffraction and scanning and transmission electron microscopies, respectively. FE properties measurement of these three types of nanostructures showed that the nanobundles have the best field emission performance with a turn-on field of ∼1.4 V/μm and a threshold field of ∼5.38 V/μm. These characteristics make VO 2 (B) nanostructures a competitive cathode material in field emission devices.

  3. Complex Quasi-Two-Dimensional Crystalline Order Embedded in VO2 and Other Crystals

    Science.gov (United States)

    Lovorn, Timothy; Sarker, Sanjoy K.

    2017-07-01

    Metal oxides such as VO2 undergo structural transitions to low-symmetry phases characterized by intricate crystalline order, accompanied by rich electronic behavior. We derive a minimal ionic Hamiltonian based on symmetry and local energetics which describes structural transitions involving all four observed phases, in the correct order. An exact analysis shows that complexity results from the symmetry-induced constraints of the parent phase, which forces ionic displacements to form multiple interpenetrating groups using low-dimensional pathways and distant neighbors. Displacements within each group exhibit independent, quasi-two-dimensional order, which is frustrated and fragile. This selective ordering mechanism is not restricted to VO2 : it applies to other oxides that show similar complex order.

  4. Local Peltier-effect-induced reversible metal–insulator transition in VO2 nanowires

    International Nuclear Information System (INIS)

    Takami, Hidefumi; Kanki, Teruo; Tanaka, Hidekazu

    2016-01-01

    We report anomalous resistance leaps and drops in VO 2 nanowires with operating current density and direction, showing reversible and nonvolatile switching. This event is associated with the metal–insulator phase transition (MIT) of local nanodomains with coexistence states of metallic and insulating phases induced by thermoelectric cooling and heating effects. Because the interface of metal and insulator domains has much different Peltier coefficient, it is possible that a significant Peltier effect would be a source of the local MIT. This operation can be realized by one-dimensional domain configuration in VO 2 nanowires because one straight current path through the electronic domain-interface enables theoretical control of thermoelectric effects. This result will open a new method of reversible control of electronic states in correlated electron materials.

  5. Running Performance, VO2max, and Running Economy: The Widespread Issue of Endogenous Selection Bias.

    Science.gov (United States)

    Borgen, Nicolai T

    2018-05-01

    Studies in sport and exercise medicine routinely use samples of highly trained individuals in order to understand what characterizes elite endurance performance, such as running economy and maximal oxygen uptake VO 2max . However, it is not well understood in the literature that using such samples most certainly leads to biased findings and accordingly potentially erroneous conclusions because of endogenous selection bias. In this paper, I review the current literature on running economy and VO 2max , and discuss the literature in light of endogenous selection bias. I demonstrate that the results in a large part of the literature may be misleading, and provide some practical suggestions as to how future studies may alleviate endogenous selection bias.

  6. VO2 kinetics and performance in soccer players after intense training and inactivity

    DEFF Research Database (Denmark)

    Christensen, Peter Møller; Krustrup, Peter; Gunnarsson, Thomas P.

    2011-01-01

    18 elite soccer players were, for a two-week period, assigned to a high intensity training group (HI, n=7) performing 10 training sessions mainly consisting of aerobic high intensity training (8×2 min) and speed endurance training (10-12×30-s sprints) or a training cessation group (TC, n=11......PURPOSE:: To examine the effects of a short-term period with intensified training or training cessation of trained soccer players on VO2 kinetics at 75% maximal aerobic speed (MAS), oxidative enzymes and performance in repeated high intensity exercise. METHODS:: After the last match of the season......) that refrained from training. RESULTS:: For TC, VO2 kinetics became slower (P...

  7. Crystal Structure and Spectroscopic Characterization of K8(VO)2O(SO4)6:

    DEFF Research Database (Denmark)

    Rasmussen, Søren Birk; Rasmussen, Rikke Christina; Fehrmann, Rasmus

    2003-01-01

    Red and yellow dichroistic crystals of a vanadium(V) compound, potassium (mu-oxo, di-mu-suifato)bis(oxodisulfato-vanadate), K-8(VO)(2)O(SO4)(6), have been obtained from the ternary catalytic model melt system K2S2O7-K2SO4-V2O5. By slow cooling of the melt from 420 to 355 degreesC, crystal growth...

  8. 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.

  9. The highest velocity and the shortest duration permitting attainment of VO2max during running

    Directory of Open Access Journals (Sweden)

    Tiago Turnes

    2015-02-01

    Full Text Available DOI: http://dx.doi.org/10.5007/1980-0037.2015v17n2p226   The severe-intensity domain has important applications for the prescription of running training and the elaboration of experimental designs. The objectives of this study were: 1 to investigate the validity of a previously proposed model to estimate the shortest exercise duration (TLOW and the highest velocity (VHIGH at which VO2max is reached during running, and 2 to evaluate the effects of aerobic training status on these variables. Eight runners and eight physically active subjects performed several treadmill running exercise tests to fatigue in order to mathematically estimate and to experimentally determine TLOW and VHIGH. The relationship between the time to achieve VO2max and time to exhaustion (Tlim was used to estimate TLOW. VHIGH was estimated using the critical velocity model. VHIGH was assumed to be the highest velocity at which VO2 was equal to or higher than the average VO2max minus one standard deviation. TLOW was defined as Tlim associated with VHIGH. Runners presented better aerobic fitness and higher VHIGH (22.2 ± 1.9 km.h-1 than active subjects (20.0 ± 2.1 km.h-1. However, TLOW did not differ between groups (runners: 101 ± 39 s; active subjects: 100 ± 35 s. TLOW and VHIGH were not well estimated by the model proposed, with high coefficients of variation (> 6% and a low correlation coefficient (r<0.70, a fact reducing the validity of the model. It was concluded that aerobic training status positively affected only VHIGH. Furthermore, the model proposed presented low validity to estimate the upper boundary of the severe-intensity domain (i.e., VHIGH, irrespective of the subjects’ training status.

  10. 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...

  11. Electronic transport in VO2—Experimentally calibrated Boltzmann transport modeling

    International Nuclear Information System (INIS)

    Kinaci, Alper; Rosenmann, Daniel; Chan, Maria K. Y.; Kado, Motohisa; Ling, Chen; Zhu, Gaohua; Banerjee, Debasish

    2015-01-01

    Materials that undergo metal-insulator transitions (MITs) are under intense study, because the transition is scientifically fascinating and technologically promising for various applications. Among these materials, VO 2 has served as a prototype due to its favorable transition temperature. While the physical underpinnings of the transition have been heavily investigated experimentally and computationally, quantitative modeling of electronic transport in the two phases has yet to be undertaken. In this work, we establish a density-functional-theory (DFT)-based approach with Hubbard U correction (DFT + U) to model electronic transport properties in VO 2 in the semiconducting and metallic regimes, focusing on band transport using the Boltzmann transport equations. We synthesized high quality VO 2 films and measured the transport quantities across the transition, in order to calibrate the free parameters in the model. We find that the experimental calibration of the Hubbard correction term can efficiently and adequately model the metallic and semiconducting phases, allowing for further computational design of MIT materials for desirable transport properties

  12. o-Iminobenzosemiquinonate and o-imino-p-methylbenzosemiquinonate anion radicals coupled VO2+ stabilization.

    Science.gov (United States)

    Roy, Amit Saha; Saha, Pinaki; Adhikary, Nirmal Das; Ghosh, Prasanta

    2011-03-21

    The diamagnetic VO(2+)-iminobenzosemiquinonate anion radical (L(R)(IS)(•-), R = H, Me) complexes, (L(-))(VO(2+))(L(R)(IS)(•-)): (L(1)(-))(VO(2+))(L(H)(IS)(•-))•3/2MeOH (1•3/2MeOH), (L(2)(-))(VO(2+))(L(H)(IS)(•-)) (2), and (L(2)(-))(VO(2+))(L(Me)(IS)(•-))•1/2 L(Me)(AP) (3•1/2 L(Me)(AP)), incorporating tridentate monoanionic NNO-donor ligands {L = L(1)(-) or L(2)(-), L(1)H = (2-[(phenylpyridin-2-yl-methylene)amino]phenol; L(2)H = 1-(2-pyridylazo)-2-naphthol; L(H)(IS)(•-) = o-iminobenzosemiquinonate anion radical; L(Me)(IS)(•-) = o-imino-p-methylbenzosemiquinonate anion radical; and L(Me)(AP) = o-amino-p-methylphenol} have been isolated and characterized by elemental analyses, IR, mass, NMR, and UV-vis spectra, including the single-crystal X-ray structure determinations of 1•3/2MeOH and 3•1/2 L(Me)(AP). Complexes 1•3/2MeOH, 2, and 3•1/2 L(Me)(AP) absorb strongly in the visible region because of intraligand (IL) and ligand-to-metal charge transfers (LMCT). 1•3/2MeOH is luminescent (λ(ext), 333 nm; λ(em), 522, 553 nm) in frozen dichloromethane-toluene glass at 77 K due to π(diimine→)π(diimine)* transition. The V-O(phenolato) (cis to the V═O) lengths, 1.940(2) and 1.984(2) Å, respectively, in 1•3/2MeOH and 3•1/2 L(Me)(AP) are consistent with the VO(2+) description. The V-O(iminosemiquinonate) (trans to the V═O) lengths, 2.1324(19) in 1•3/2MeOH and 2.083(2) Å in 3•1/2 L(Me)(AP), are expectedly ∼0.20 Å longer due to the trans influence of the V═O bond. Because of the stronger affinity of the paramagnetic VO(2+) ion to the L(H)(IS)(•-) or L(Me)(IS)(•-), the V-N(iminosemiquinonate) lengths, 1.908(2) and 1.921(2) Å, respectively, in 1•3/2MeOH and 3•1/2 L(Me)(AP), are unexpectedly shorter. Density functional theory (DFT) calculations using B3LYP, B3PW91, and PBE1PBE functionals on 1 and 2 have established that the closed shell singlet (CSS) solutions (VO(3+)-amidophenolato (L(R)(AP)(2-)) coordination) of these

  13. Biochemical background of the VO2 on-kinetics in skeletal muscles.

    Science.gov (United States)

    Korzeniewski, Bernard; Zoladz, Jerzy A

    2006-02-01

    This review discusses the present knowledge on the oxygen uptake kinetics at the onset of exercise in skeletal muscle and the contribution of a previously developed computer model of oxidative phosphorylation in intact skeletal muscle to the understanding of the factors determining this kinetics on the biochemical level. It has been demonstrated recently that an increase in the total creatine pool [PCr + Cr] and in glycolytic ATP supply lengthen the half-transition time of the VO2 on-kinetics, while an increase in mitochondria content, in parallel activation of ATP supply and ATP usage, in muscle oxygen concentration, in proton leak, in resting energy demand, in resting cytosolic pH, and in initial alkalization diminish this parameter. It has also been shown that the half-transition time is near-linearly proportional to the absolute difference between the phosphocreatine concentration during work and at rest (deltaPCr). The present review discusses whether the V/O2 on-kinetics on the muscle level is strictly or only approximately exponential. Finally, it is postulated that a short transition time of the VO2 on-kinetics in itself does not need be profitable for the skeletal muscle functioning during exercise, but usually a short transition time is correlated with factors that improve exercise capacity. The transition time is a phenomenological parameter resulting from the biochemical properties of the system and not a physical factor that can cause anything in the system.

  14. Stoichiometric and Oxygen-Deficient VO2 as Versatile Hole Injection Electrode for Organic Semiconductors.

    Science.gov (United States)

    Fu, Keke; Wang, Rongbin; Katase, Takayoshi; Ohta, Hiromichi; Koch, Norbert; Duhm, Steffen

    2018-03-28

    Using photoemission spectroscopy, we show that the surface electronic structure of VO 2 is determined by the temperature-dependent metal-insulator phase transition and the density of oxygen vacancies, which depends on the temperature and ultrahigh vacuum (UHV) conditions. The atomically clean and stoichiometric VO 2 surface is insulating at room temperature and features an ultrahigh work function of up to 6.7 eV. Heating in UHV just above the phase transition temperature induces the expected metallic phase, which goes in hand with the formation of oxygen defects (up to 6% in this study), but a high work function >6 eV is maintained. To demonstrate the suitability of VO 2 as hole injection contact for organic semiconductors, we investigated the energy-level alignment with the prototypical organic hole transport material N, N'-di(1-naphthyl)- N, N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (NPB). Evidence for strong Fermi-level pinning and the associated energy-level bending in NPB is found, rendering an Ohmic contact for holes.

  15. EVALUATION AND COMPARISON OF VO2MAX ASSESSMENT MODELS IN HIGH SCHOOL STUDENTS

    Directory of Open Access Journals (Sweden)

    Bolboli Lotfali

    2013-04-01

    Full Text Available The purpose of this study was to evaluation and comparison of VO2max assessment models in students. Thirty students from high schools of Ardabil city were selected randomly and served as subjects in this study (age: 15.73±0.69 year, height: 169.46±8.1 cm, weight: 61.70±9.32 kg. Subjects were divided into two groups. In one group Rockport test was used to estimate their VO2 max and in other group Balk test was used for the same purpose. Also, the VO2max of both groups were examined by a standard treadmill test and the results were compared with the results of field tests. The one way of ANOVA and Tukey's post-hoc tests were used for data analysis (p>0/05. The results showed that there were significant differences between the results of the field tests and standard treadmill test (Bruce: 40.93±5.83 vs. Rockport: 58.71±2.73 and Balke: 52.09± 6.18. As a result of these findings it was concluded that the regression equations used in this study used is not suitable for 15-17 (yr boys and does not estimate their aerobic power correctly.

  16. Insulator-metal transition in substrate-independent VO2 thin film for phase-change devices.

    Science.gov (United States)

    Taha, Mohammad; Walia, Sumeet; Ahmed, Taimur; Headland, Daniel; Withayachumnankul, Withawat; Sriram, Sharath; Bhaskaran, Madhu

    2017-12-20

    Vanadium has 11 oxide phases, with the binary VO 2 presenting stimuli-dependent phase transitions that manifest as switchable electronic and optical features. An elevated temperature induces an insulator-to-metal transition (IMT) as the crystal reorients from a monoclinic state (insulator) to a tetragonal arrangement (metallic). This transition is accompanied by a simultaneous change in optical properties making VO 2 a versatile optoelectronic material. However, its deployment in scalable devices suffers because of the requirement of specialised substrates to retain the functionality of the material. Sensitivity to oxygen concentration and larger-scale VO 2 synthesis have also been standing issues in VO 2 fabrication. Here, we address these major challenges in harnessing the functionality in VO 2 by demonstrating an approach that enables crystalline, switchable VO 2 on any substrate. Glass, silicon, and quartz are used as model platforms to show the effectiveness of the process. Temperature-dependent electrical and optical characterisation is used demonstrating three to four orders of magnitude in resistive switching, >60% chromic discrimination at infrared wavelengths, and terahertz property extraction. This capability will significantly broaden the horizon of applications that have been envisioned but remained unrealised due to the lack of ability to realise VO 2 on any substrate, thereby exploiting its untapped potential.

  17. Pengaruh metode latihan dan daya tahan otot tungkai terhadap hasil peningkatan kapasitas VO2Max pemain bola basket

    Directory of Open Access Journals (Sweden)

    Gregorius Pito Wahyu Prakoso

    2017-09-01

    Abstract This study aims to determine: (1 differences in the influence of methods of circuit training and interval method of training on the increase in capacity VO2Max basketball (2 the difference of increase in capacity VO2Max basketball resilient tall limb muscle and muscular endurance leg lower the increase in capacity VO2Max basketball, and (3 the interaction between exercise and limb muscle endurance against the increase in capacity VO2Max basketball. This research method used experiments with 2 x 2 factorial design study. The research sample of 20 children trained were taken with purposive sampling technique. Data were analyzed using analysis of variants (ANOVA. The results of this study indicate that: (1 there is no significant difference between exercise training method circuit training and training methods interval training against the increase in capacity VO2Max basketball, (2 There are no significant differences in increase in capacity VO2Max basketball among students who have the endurance of leg muscle and durability of  low leg muscle, (3 there is no interaction between the method of training (circuit training and interval training and leg muscle endurance against the increase in capacity VO2Max basketball.

  18. Physiological background of the change point in VO2 and the slow component of oxygen uptake kinetics.

    Science.gov (United States)

    Zoładź, J A; Korzeniewski, B

    2001-06-01

    It is generally believed that oxygen uptake during incremental exercise--until VO2max, increases linearly with power output (see eg. Astrand & Rodahl, 1986). On the other hand, it is well established that the oxygen uptake reaches a steady state only during a low power output exercise, but during a high power output exercise, performed above the lactate threshold (LT), the oxygen uptake shows a continuous increase until the end of the exercise. This effect has been called the slow component of VO2 kinetics (Whipp & Wasserman, 1972). The presence of a slow component in VO2 kinetics implies that during an incremental exercise test, after the LT has been exceeded, the VO2 to power output relationship has to become curvilinear. Indeed, it has recently been shown that during the incremental exercise, the exceeding of the power output, at which blood lactate begins to accumulate (LT), causes a non-proportional increase in VO2 (Zoladz et al. 1995) which indicates a drop in muscle mechanical efficiency. The power output at which VO2 starts to rise non-proportionally to the power output has been called "the change point in VO2" (Zoladz et al. 1998). In this paper, the significance of the factors most likely involved in the physiological mechanism responsible for the change point in oxygen uptake (CP-VO2) and for the slow component of VO2 kinetics, including: increase of activation of additional muscle groups, intensification of the respiratory muscle activity, recruitment of type II muscle fibres, increase of muscle temperature, increase of the basal metabolic rate, lactate and hydrogen ion accumulation, proton leak through the inner mitochondrial membrane, slipping of the ATP synthase and a decrease in the cytosolic phosphorylation potential, are discussed. Finally, an original own model describing the sequence of events leading to the non-proportional increase of oxygen cost of work at a high exercise intensity is presented.

  19. Tuning the work function of VO_2(1 0 0) surface by Ag adsorption and incorporation: Insights from first-principles calculations

    International Nuclear Information System (INIS)

    Chen, Lanli; Wang, Xiaofang; Shi, Siqi; Cui, Yuanyuan; Luo, Hongjie; Gao, Yanfeng

    2016-01-01

    Graphical abstract: - Highlights: • After adsorption, there is a charge transfer from Ag to VO_2(1 0 0) surface, which thus increases the electron concentration in VO_2 thin film. • Ag adsorption on VO_2(1 0 0) surface process is an exothermic chemical process, and the adsorption system is stable. • The work function can be tuned by Ag adsorption on and incorporation into the VO_2(1 0 0) surface, which in turn regulates the phase transition temperature of VO_2. - Abstract: VO_2 is an attractive material for application to thermochromic optoelectronic devices such as smart windows, and Ag/VO_2 double-layered structure can effectively decrease the phase transition temperature (T_c) of VO_2 thin film, which is very important for practical application of VO_2. Previous works has shown that the decrease in phase transition temperature (T_c) seems to be relevant with the work function of VO_2 in Ag/VO_2 double-layered thin film, although the underlying mechanism of tuning its T_c by Ag incorporation and adsorption on the VO_2(1 0 0) surface has been rarely investigated. Our first-principles calculations reveal that the adsorption of Ag atoms on the VO_2(1 0 0) surface rather than incorporation of Ag exhibits a lower work function, which is ascribed to an integrated effect of charge transfer from Ag to VO_2(1 0 0) surface and enhanced surface dipole moment. The results suggest that the decrease in work function of VO_2 with Ag adsorption favors the reduction in T_c. The current findings are helpful to understand the fundamental mechanism for yielding high-efficiency VO_2-based optoelectronic devices.

  20. Peak oxygen uptake in swimmers and pupils

    Directory of Open Access Journals (Sweden)

    Emilson Colantonio

    2008-01-01

    The objectives of this study were: a to analyze the behavior of VO2MAX (absolute and relative of males of different age groups sex; b to compare VO2MAX (absolute and relative, of swimmers (SWM and schoolchildren (SCH in the same age groups. Seventy-one boys aged 7-17 years were evaluated (35 SWM and 36 SCH and distributed into the age groups 7-10, 11-14 and 15-17 years. Anthropometric measurements were taken (height, body mass and sum of skin folds and the metabolic (VO2MAX tests were carried out using VO2000® gas analysis and an Inbrasport ATL® treadmill, using a modified version of the Bruce protocol. Statistical analysis: ANOVA for repeated measures, followed by Tukey’s post hoc test (p<0.05. Absolute VO2MAX: there were statistically significant differences between all age groups and between SWM (0.99 + 0.20 and 1.27 + 0.21 L.min-1 and SCH (0.98 + 0.36 and 0.80 + 0.12 L.min-1. Relative VO2MAX: there were statistically significant differences between SWM1 and SWM2 (10.88 + 0.09 and 0.75 + 0.47 ml.kg-1.min-1 and between SCH1 and SCH3 (6.96 + 1.23 and 0.98 + 2.29 ml.kg-1.min-1, although SWM and SCH were different. The results indicate that VO2MAX increased as the subjects got older, which is the result of natural development. However, the effect of swimming training predominated. Although the behavior of the variable was similar for the 11-14 and 15-17 age groups, the figures for SWM and SCH are different at these ages, with the swimmers having higher VO2MAX.

  1. Climate-related variation in plant peak biomass and growth phenology across Pacific Northwest tidal marshes

    Science.gov (United States)

    Buffington, Kevin J.; Dugger, Bruce D.; Thorne, Karen M.

    2018-01-01

    The interannual variability of tidal marsh plant phenology is largely unknown and may have important ecological consequences. Marsh plants are critical to the biogeomorphic feedback processes that build estuarine soils, maintain marsh elevation relative to sea level, and sequester carbon. We calculated Tasseled Cap Greenness, a metric of plant biomass, using remotely sensed data available in the Landsat archive to assess how recent climate variation has affected biomass production and plant phenology across three maritime tidal marshes in the Pacific Northwest of the United States. First, we used clipped vegetation plots at one of our sites to confirm that tasseled cap greenness provided a useful measure of aboveground biomass (r2 = 0.72). We then used multiple measures of biomass each growing season over 20–25 years per study site and developed models to test how peak biomass and the date of peak biomass varied with 94 climate and sea-level metrics using generalized linear models and Akaike Information Criterion (AIC) model selection. Peak biomass was positively related to total annual precipitation, while the best predictor for date of peak biomass was average growing season temperature, with the peak 7.2 days earlier per degree C. Our study provides insight into how plants in maritime tidal marshes respond to interannual climate variation and demonstrates the utility of time-series remote sensing data to assess ecological responses to climate stressors.

  2. Climate-related variation in plant peak biomass and growth phenology across Pacific Northwest tidal marshes

    Science.gov (United States)

    Buffington, Kevin J.; Dugger, Bruce D.; Thorne, Karen M.

    2018-03-01

    The interannual variability of tidal marsh plant phenology is largely unknown and may have important ecological consequences. Marsh plants are critical to the biogeomorphic feedback processes that build estuarine soils, maintain marsh elevation relative to sea level, and sequester carbon. We calculated Tasseled Cap Greenness, a metric of plant biomass, using remotely sensed data available in the Landsat archive to assess how recent climate variation has affected biomass production and plant phenology across three maritime tidal marshes in the Pacific Northwest of the United States. First, we used clipped vegetation plots at one of our sites to confirm that tasseled cap greenness provided a useful measure of aboveground biomass (r2 = 0.72). We then used multiple measures of biomass each growing season over 20-25 years per study site and developed models to test how peak biomass and the date of peak biomass varied with 94 climate and sea-level metrics using generalized linear models and Akaike Information Criterion (AIC) model selection. Peak biomass was positively related to total annual precipitation, while the best predictor for date of peak biomass was average growing season temperature, with the peak 7.2 days earlier per degree C. Our study provides insight into how plants in maritime tidal marshes respond to interannual climate variation and demonstrates the utility of time-series remote sensing data to assess ecological responses to climate stressors.

  3. VO2/TiO2 Nanosponges as Binder-Free Electrodes for High-Performance Supercapacitors

    Science.gov (United States)

    Hu, Chenchen; Xu, Henghui; Liu, Xiaoxiao; Zou, Feng; Qie, Long; Huang, Yunhui; Hu, Xianluo

    2015-11-01

    VO2/TiO2 nanosponges with easily tailored nanoarchitectures and composition were synthesized by electrostatic spray deposition as binder-free electrodes for supercapacitors. Benefiting from the unique interconnected pore network of the VO2/TiO2 electrodes and the synergistic effect of high-capacity VO2 and stable TiO2, the as-formed binder-free VO2/TiO2 electrode exhibits a high capacity of 86.2 mF cm-2 (~548 F g-1) and satisfactory cyclability with 84.3% retention after 1000 cycles. This work offers an effective and facile strategy for fabricating additive-free composites as high-performance electrodes for supercapacitors.

  4. Fourier transform infrared study of the phase transitions in (NH4)3VO2FO4

    Science.gov (United States)

    de Waal, D.; Heyns, A. M.

    1994-01-01

    Ammonium oxofluorovanadate compounds are known to show some potential as ferroelectric materials. The whole series of ammonium and sodium oxofluorovanadate compounds including Na3VO2F4 have already been prepared and investigated by means of various techniques including x-ray diffraction, EPR, and vibrational spectroscopy. It was established that the pure ammonium compound shows the two above mentioned transitions from phase A (below 200 K) to phase B (between 200 and 400 K) and phase C (above 400 K) while Na(NH4)2VO2F4 has only one transition from phase A to phase B around 400 K4. In the present study various aspects regarding the nature of the structures of (NH4)3VO2F3 and Na(NH4)2VO2F4 and its influence on the phase transitions have been investigated.

  5. VO2/TiO2 Nanosponges as Binder-Free Electrodes for High-Performance Supercapacitors.

    Science.gov (United States)

    Hu, Chenchen; Xu, Henghui; Liu, Xiaoxiao; Zou, Feng; Qie, Long; Huang, Yunhui; Hu, Xianluo

    2015-11-04

    VO2/TiO2 nanosponges with easily tailored nanoarchitectures and composition were synthesized by electrostatic spray deposition as binder-free electrodes for supercapacitors. Benefiting from the unique interconnected pore network of the VO2/TiO2 electrodes and the synergistic effect of high-capacity VO2 and stable TiO2, the as-formed binder-free VO2/TiO2 electrode exhibits a high capacity of 86.2 mF cm(-2) (~548 F g(-1)) and satisfactory cyclability with 84.3% retention after 1000 cycles. This work offers an effective and facile strategy for fabricating additive-free composites as high-performance electrodes for supercapacitors.

  6. Why is VO2 max after altitude acclimatization still reduced despite normalization of arterial O2 content?

    DEFF Research Database (Denmark)

    Calbet, J A L; Boushel, Robert Christopher; Radegran, G

    2003-01-01

    Acute hypoxia (AH) reduces maximal O2 consumption (VO2 max), but after acclimatization, and despite increases in both hemoglobin concentration and arterial O2 saturation that can normalize arterial O2 concentration ([O2]), VO2 max remains low. To determine why, seven lowlanders were studied at VO2......% of the cardiac output perfused the legs, in CH the legs received only 67%. Pulmonary VO2 max (4.1 +/- 0.3 l/min at SL) fell to 2.2 +/- 0.1 l/min in AH (P normalization...... of arterial [O2] is explained by two circulatory effects of altitude: 1) failure of cardiac output to normalize and 2) preferential redistribution of cardiac output to nonexercising tissues. Oxygen transport from blood to muscle mitochondria, on the other hand, appears unaffected by CH....

  7. A cost-effective process to prepare VO2 (M) powder and films with superior thermochromic properties

    International Nuclear Information System (INIS)

    Xiao, Xiudi; Zhang, Hua; Chai, Guanqi; Sun, Yaoming; Yang, Tao; Cheng, Haoliang; Chen, Lihua; Miao, Lei; Xu, Gang

    2014-01-01

    Graphical abstract: Combining codeposition and short time post annealing, VO 2 (M) with high quality and excellent phase transition performance is obtained. After mixing the VO 2 powder with acrylic resin, the composite films deposited on glass show superior visible transmission and solar modulation, which can be used as an excellent candidate of low cost smart window in energy saving field. - Highlights: • The VO 2 powder obtained by short time thermolysis method is high purity and crystallinity with superior phase transition performance. • The maximum decreasing efficiency of phase transition temperature is about −30 K/at% with w = 0.4 at%. • After mixing VO 2 powder with acrylic resin, the maximal visible transmission of the composite films is 48% and the transmission modulation at 2000 nm is 37.3% with phase transition temperature of 66.2 °C. • Though the phase transition performance is weakened by tungsten doping, the film prepared by 1.3 at% tungsten doped VO 2 still show superior transmission modulation about 26.4%, which means that it is a potential candidate as smart windows. - Abstract: VO 2 powder with superior phase transition performance was prepared by convenient thermolysis method. The results illustrated that VO 2 powder show high purity and crystallinity. VO 2 particles are transformed from cluster to quasi-sphere with the increase of annealing temperature. The DSC analysis proves that VO 2 show superior phase transition performance around 68 °C. The phase transition temperature can be reduced to 33.5 °C by 1.8 at% tungsten doping. The maximum decreasing efficiency of phase transition temperature is about −30 K/at% with w = 0.4 at%. After mixing VO 2 powder with acrylic resin, the maximal visible transmission of the composite thin films on glass is 48% and the transmission modulation at 2000 nm is 37.3% with phase transition temperature of 66.2 °C. Though the phase transition performance is weakened by tungsten doping, the film

  8. Sex Comparisons for Relative Peak Torque and Electromyographic Mean Frequency during Fatigue

    Science.gov (United States)

    Stock, Matt S.; Beck, Travis W.; DeFreitas, Jason M.; Ye, Xin

    2013-01-01

    Purpose: This study compared the relative peak torque and normalized electromyographic (EMG) mean frequency (MNF) responses during fatiguing isokinetic muscle actions for men versus women. Method: Twenty men M[subscript age] ± SD = 22 ± 2 years) and 20 women M[subscript age] ± SD = 22 ± 1 years) performed 50 maximal concentric isokinetic muscle…

  9. Applicability of an Indirect VO2max Test: Its Association with the 400 Meters Freestyle Performance

    Directory of Open Access Journals (Sweden)

    Adalberto Veronese da Costa

    Full Text Available Abstract The aim of this study was to evaluate the VO2max using a previously validated indirect test for non-expert adult swimmers and to verify its connection with the 400 meters freestyle test. A total of 17 non-expert male swimmers (21.5 ± 3.12 years were evaluated. Body composition measurements included body weight (74 ± 9.41 kg, height (172.9 ± 5.21 cm and body fat percentage (15.2 ± 4.15 %. Two tests were conducted on different days; the 400 meters freestyle (400 MF and the Progressive Swim Test (PSwT, respectively. The participant's heart rate frequency before and after the test (BHR and AHR was analyzed, as well as the subjective perception of effort (RPE, the number of laps covered (NLP, and the time of test execution measured in minutes. Significant differences were identified in all variables (p - 0.60 was found between AHR and execution time (r > - 0.70, as well as between the VO2max estimated by the PSwT and the 400 MF performance test (r > - 0.70. The Bland-Altman Plot showed that the values discovered were within the established concordance limits of 95% (±1.96 SD. A negative correlation between a swimming test and a test that estimates the VO2max occurred, and the PSwT showed results of greater approximation of the aerobic power of non-expert swimmers. In conclusion, the PSwT is applicable for non-expert adult swimmers.

  10. SnO2@C@VO2 Composite Hollow Nanospheres as an Anode Material for Lithium-Ion Batteries.

    Science.gov (United States)

    Guo, Wenbin; Wang, Yong; Li, Qingyuan; Wang, Dongxia; Zhang, Fanchao; Yang, Yiqing; Yu, Yang

    2018-05-02

    Porous SnO 2 @C@VO 2 composite hollow nanospheres were ingeniously constructed through the combination of layer-by-layer deposition and redox reaction. Moreover, to optimize the electrochemical properties, SnO 2 @C@VO 2 composite hollow nanospheres with different contents of the external VO 2 were also studied. On the one hand, the elastic and conductive carbon as interlayer in the SnO 2 @C@VO 2 composite can not only buffer the huge volume variation during repetitive cycling but also effectively improve electronic conductivity and enhance the utilizing rate of SnO 2 and VO 2 with high theoretical capacity. On the other hand, hollow nanostructures of the composite can be consolidated by the multilayered nanocomponents, resulting in outstanding cyclic stability. In virtue of the above synergetic contribution from individual components, SnO 2 @C@VO 2 composite hollow nanospheres exhibit a large initial discharge capacity (1305.6 mAhg -1 ) and outstanding cyclic stability (765.1 mAhg -1 after 100 cycles). This design of composite hollow nanospheres may be extended to the synthesis of other nanomaterials for electrochemical energy storage.

  11. Structure of Co(2), Ni(2) and VO(2) complexes with 4-phenylthiosemicarbaziddiacetic acid

    International Nuclear Information System (INIS)

    Kravtsov, V.Kh.; Kipkovskij, Ya.; Bologa, O.A.; Lozan, V.I.; Simonov, Yu.A.; Gehrbehlehu, N.V.; Malinovskij, T.I.; AN Moldavskoj SSR, Kishinev

    1995-01-01

    Structure of complex compounds VO(2)(3) with 4-phyenylthiosemicarbaziddiacetic acid is determined through X-ray diffraction method. Monocrystal compounds are monoclinic, sp.gr. P2 1 /n (a=6.703(2), b=12.470(7), c=1695(6) A, γ=95.10(4) deg). The organic molecule in the complexes is expressed in form of twofold deprotonated tetradentate, ligand joining to metal according to the tripod type with application of donor atoms S, N, O, O and forming three metallocycles. The coordination surrounding of the central atom is supplemented by one oxygen vanadyl atom and one water molecule. 17 refs.; 4 figs.; 5 tabs

  12. 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...

  13. Dynamic Control of Light Emission Faster than the Lifetime Limit Using VO2 Phase-Change

    Science.gov (United States)

    2015-10-22

    2D colour plot of the calculated modulation amplitude of the MD contribution to Er3þ emission at 1.5mm upon the VO2 phase-change, as a function of TiO2...metallic state. Experimental spectra are shown in shaded red and blue colour , respectively, whereas theoretically predicted spectra are shown as black...model in Rakić et al.31. References 1. Loke, D. et al. Breaking the speed limits of phase-change memory . Science 336, 1566–1569 (2012). 2. Cavalleri

  14. A one-parametric formula relating the frequencies of twin-peak quasi-periodic oscillations

    Science.gov (United States)

    Török, Gabriel; Goluchová, Kateřina; Šrámková, Eva; Horák, Jiří; Bakala, Pavel; Urbanec, Martin

    2017-12-01

    Timing analysis of X-ray flux in more than a dozen low-mass X-ray binary systems containing a neutron star reveals remarkable correlations between frequencies of two characteristic peaks present in the power-density spectra. We find a simple analytic relation that well reproduces all these individual correlations. We link this relation to a physical model which involves accretion rate modulation caused by an oscillating torus.

  15. Variação diurna e resposta da cinética do VO2 de ciclistas durante exercício muito intenso Diurnal variation and Vo2 kinetic response of cyclists during heavy exercis e

    Directory of Open Access Journals (Sweden)

    Marcos G. Santana

    2008-06-01

    Full Text Available O objetivo do presente estudo foi avaliar a influência da hora do dia nos parâmetros da cinética do consumo de oxigênio de ciclistas durante exercício muito intenso. Nove voluntários do sexo masculino realizaram exercícios de carga constante às 08:00, 13:00 e 18:00 h, em dias diferentes. Estes exercícios foram realizados duas vezes em cada visita, com um intervalo de 1 h entre eles. A intensidade usada foi de 75%Δ (75% da diferença entre o VO2 no limiar de lactato e o VO2max. A amplitude do componente primário do VO2 (2597 ± 273 ml.min-1, 2513 ± 268 ml.min-1 e 2609 ± 370 ml.min-1, a constante de tempo do componente primário do VO2 (19.3 ± 2.5 s, 18.4 ± 3.0 s e 19.7 ± 3.9 s, o componente lento do VO2 (735 ± 81 ml.min-1, 764 ± 99 ml.min-1 e 680 ± 121 ml.min-1 e o tempo de resposta média (51.8 ± 4.2 s, 51.2 ± 4.2 s e 51.4 ± 3.4 s não apresentaram diferenças significativas entre os diferentes horários do dia (08:00, 13:00 e 18:00 h, assim como os demais parâmetros da cinética do VO2. Estes resultados sugerem que a resposta da cinética do VO2 de ciclistas durante exercício muito intenso (75%Δ não é influenciada pela hora do dia.The objective of the present study was to evaluate the influence of the time of day on the parameters of oxygen uptake kinetics of trained cyclists during high intensity exercise. Nine male volunteers repeated bouts at constant loads at 08:00, 13:00 and 18:00 h on different days. These exercise bouts were performed twice on each occasion, with an interval of 1 h between them. The load intensity used was 75%Δ (75% of the difference between the VO2 at the lactate threshold and the VO2max. The primary VO2 amplitude (2597 ± 273 ml.min-1, 2513 ± 268 ml.min-1 and 2609 ± 370 ml.min-1, the primary VO2 time constant (19.3 ± 2.5 s, 18.4 ± 3.0 s and 19.7 ± 3.9 s, the VO2 slow component (735 ± 81 ml.min-1, 764 ± 99 ml.min-1 and 680 ± 121 ml.min-1 and the mean response time (51.8 ± 4.2 s, 51

  16. Seasonal variations in VO2max, O2-cost, O2-deficit, and performance in elite cross-country skiers.

    Science.gov (United States)

    Losnegard, Thomas; Myklebust, Håvard; Spencer, Matt; Hallén, Jostein

    2013-07-01

    Long-term effects of training are important information for athletes, coaches, and scientists when associating changes in physiological indices with changes in performance. Therefore, this study monitored changes in aerobic and anaerobic capacities and performance in a group of elite cross-country skiers during a full sport season. Thirteen men (age, 23 ± 2 years; height, 182 ± 6 cm; body mass, 76 ± 8 kg; V2 roller ski skating VO2max, 79.3 ± 4.4 ml·kg·min or 6.0 ± 0.5 L·min) were tested during the early, middle, and late preparation phase: June (T1), August (T2), and October (T3); during the competition phase: January/February (T4); and after early precompetition phase: June (T5). O2-cost during submaximal efforts, V[Combining Dot Above]O2peak, accumulated oxygen deficit (ΣO2-deficit), and performance during a 1,000-m test were determined in the V2 ski skating technique on a roller ski treadmill. Subjects performed their training on an individual basis, and detailed training logs were categorized into different intensity zones and exercise modes. Total training volume was highest during the summer months (early preseason) and decreased toward and through the winter season, whereas the volume of high-intensity training increased (all p size; ES = 0.63-1.37, moderate to large, all p country skiers induced no significant changes in V[Combining Dot Above]O2peak but improved performance, O2-cost, and ΣO2-deficit.

  17. Exercise tolerance during VO2max testing is a multifactorial psychobiological phenomenon.

    Science.gov (United States)

    Midgley, Adrian W; Earle, Keith; McNaughton, Lars R; Siegler, Jason C; Clough, Peter; Earle, Fiona

    2017-01-01

    Fifty-nine men completed a VO 2max test and a questionnaire to establish reasons for test termination, perceived exercise reserve (difference between actual test duration and the duration the individual perceived could have been achieved if continued until physical limitation), and perception of verbal encouragement. Participants gave between 1 and 11 factors as reasons for test termination, including leg fatigue, various perceptions of physical discomfort, safety concerns, and achievement of spontaneously set goals. The two most common main reasons were leg fatigue and breathing discomfort, which were predicted by pre-to-post test changes in pulmonary function (p = 0.038) and explosive leg strength (p = 0.042; R 2  = 0.40). Median (interquartile range) perceived exercise reserve, was 45 (50) s. Two-thirds of participants viewed verbal encouragement positively, whereas one-third had a neutral or negative perception. This study highlights the complexity of exercise tolerance during VO 2max testing and more research should explore these novel findings.

  18. Nanoscale Engineering in VO2 Nanowires via Direct Electron Writing Process.

    Science.gov (United States)

    Zhang, Zhenhua; Guo, Hua; Ding, Wenqiang; Zhang, Bin; Lu, Yue; Ke, Xiaoxing; Liu, Weiwei; Chen, Furong; Sui, Manling

    2017-02-08

    Controlling phase transition in functional materials at nanoscale is not only of broad scientific interest but also important for practical applications in the fields of renewable energy, information storage, transducer, sensor, and so forth. As a model functional material, vanadium dioxide (VO 2 ) has its metal-insulator transition (MIT) usually at a sharp temperature around 68 °C. Here, we report a focused electron beam can directly lower down the transition temperature of a nanoarea to room temperature without prepatterning the VO 2 . This novel process is called radiolysis-assisted MIT (R-MIT). The electron beam irradiation fabricates a unique gradual MIT zone to several times of the beam size in which the temperature-dependent phase transition is achieved in an extended temperature range. The gradual transformation zone offers to precisely control the ratio of metal/insulator phases. This direct electron writing technique can open up an opportunity to precisely engineer nanodomains of diversified electronic properties in functional material-based devices.

  19. Determinants of time limit at velocity corresponding to VO2max in physically active individuals

    Directory of Open Access Journals (Sweden)

    Leonardo Gonçalves Ribeiro

    2008-07-01

    Full Text Available http://dx.doi.org/10.5007/1980-0037.2008v10n1p69 The objective of the present study was to determine the relationship between time limit (Tlim at VO2Máx velocity (VVO2Máx and the variables VO2Máx, VVO2Máx, running economy (RE, ventilatory threshold (VT, strength test (9-10 maximum repetitions, velocity at maximal anaerobic running test (VMART, vertical jump test and body fat percentage. The sample was composed of 18 male volunteers, aged between 18 and 45 years old, non-athletes, but physically active. The study was carried out during fi ve visits, on non-consecutive days and at approximately the same time each day: visit 1 - signature of informed consent form, medical history, anthropometric assessment, aerobic power test and familiarization with Tlim test; visit 2 - RE test and Tlim test; visit 3 - familiarization with VMART test; visit 4 - familiarization with vertical jump and 9-10 maximum repetition tests and VMART test; visit 5 - vertical jump and 9-10 maximum repetition tests. Low (r = 0.220 to – 0.359 and non-signifi cant correlations (p = 0.281 to 0.935 were observed between Tlim and the selected variables, characterizing the low predictive value of Tlim for the sample studied. Thus, and because of the considerable inter-individual variability in Tlim, no variable was identifi ed that was capable of satisfactorily predicting Tlim.

  20. Relation between Peak Power Output in Sprint Cycling and Maximum Voluntary Isometric Torque Production.

    Science.gov (United States)

    Kordi, Mehdi; Goodall, Stuart; Barratt, Paul; Rowley, Nicola; Leeder, Jonathan; Howatson, Glyn

    2017-08-01

    From a cycling paradigm, little has been done to understand the relationships between maximal isometric strength of different single joint lower body muscle groups and their relation with, and ability to predict PPO and how they compare to an isometric cycling specific task. The aim of this study was to establish relationships between maximal voluntary torque production from isometric single-joint and cycling specific tasks and assess their ability to predict PPO. Twenty male trained cyclists participated in this study. Peak torque was measured by performing maximum voluntary contractions (MVC) of knee extensors, knee flexors, dorsi flexors and hip extensors whilst instrumented cranks measured isometric peak torque from MVC when participants were in their cycling specific position (ISOCYC). A stepwise regression showed that peak torque of the knee extensors was the only significant predictor of PPO when using SJD and accounted for 47% of the variance. However, when compared to ISOCYC, the only significant predictor of PPO was ISOCYC, which accounted for 77% of the variance. This suggests that peak torque of the knee extensors was the best single-joint predictor of PPO in sprint cycling. Furthermore, a stronger prediction can be made from a task specific isometric task. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Effects of three warm-up regimens of equal distance on VO2 kinetics during supramaximal exercise in Thoroughbred horses.

    Science.gov (United States)

    Mukai, K; Hiraga, A; Takahashi, T; Ohmura, H; Jones, J H

    2010-11-01

    Several studies have indicated that even low-intensity warm-up increases O(2) transport kinetics and that high-intensity warm-up may not be needed in horses. However, conventional warm-up exercise for Thoroughbred races is more intense than those utilised in previous studies of equine warm-up responses. To test the hypothesis that warm-up exercise at different intensities alters the kinetics and total contribution of aerobic power to total metabolic power in subsequent supramaximal (sprint) exercise in Thoroughbred horses. Nine well-trained Thoroughbreds ran until fatigue at 115% of maximal oxygen consumption (VO2max) 10 min after warming-up under each of 3 protocols of equal running distance: 400 s at 30% VO2max (LoWU), 200 s at 60% VO2max (MoWU) and 120 s at 100% VO2max (HiWU). Variables measured during exercise were rates of O(2) and CO(2) consumption/production (VO2,VO2), respiratory exchange ratio (RER), heart rate, blood lactate concentration and accumulation rate and blood gas variables. VO2 was significantly higher in HiWU than in LoWU at the onset of the sprint exercise and HR was significantly higher in HiWU than in LoWU throughout the sprint. Accumulation of blood lactate, RER, P(a)CO(2) and PvCO2 in the first 60 s were significantly lower in HiWU than in LoWU and MoWU. There were no significant differences in stroke volume, run time or arterial-mixed venous O(2) concentration. These results suggest HiWU accelerates kinetics and reduces reliance on net anaerobic power compared with LoWU at the onset of the subsequent sprint. © 2010 EVJ Ltd.

  2. Physical performance and peak aerobic power at different body temperatures.

    Science.gov (United States)

    Bergh, U; Ekblom, B

    1979-05-01

    In eight male subjects we studied the effect of different core (esophageal, (Tes 34.9--38.4 degrees C) and muscle (Tm 35.1--39.3 degrees C) temperature on 1) physical performance (time to exhaustion at a standard maximal rate of work, WT), 2) aerobic power (VO2), 3) heart rate (HR), and 4) blood lactate (LA) concentration during exhaustive combined arm and leg exercise. In three subjects the effects at different mean skin temperatures (Tsk 27 and 31 degrees C, respectively) were also studied. Peak VO2 was positively correlated to both Tes (r = 0.88) and Tm (r = 0.91). None of the subjects attained control VO2max at Tes and Tm lower than 37.5 and 38.0 degrees C, respectively. HR was correlated to both Tes (r = 0.97) and Tm (r = 0.95). Different Tsk did not affect peak VO2 and HR at subnormal body temperatures. Pulmonary ventilation was independent of Tes and Tm in all experimental situations. LA was significantly higher at Tes 37.5 degrees C compared to both Tes 34.9 and 38.5 degrees C, respectively. At Tes less than 37.5 degrees C and Tm less than 38.0 degrees C, there was a linear reduction in WT (20%.degrees C-1), peak VO2 (5--6%.degrees C-1), and HR (8 beats.min-1.degrees C-1) with lowered Tes and Tm.

  3. Body composition, VO2máx. and the lifestyle of young students of the higher education

    Directory of Open Access Journals (Sweden)

    R.M. Antúnez

    2008-01-01

    Full Text Available OBJECTIVE: The purpose of this study was to characterize the subjects of the sample in what concerns their corporal composition, through the index of corporal mass and of the percentage of fat mass, their cardiorespiratory capacity, their eating and smoking habits, and indexes of practice of physical activity. It also aimed to verify if there were statistically relevant relationships between these variables. METHODS: The study was carried out in 2006 and 2007, in Beja, a city in the South of Portugal. The sample comprised 183 students attending the first year of all the courses of a higher education institution in the school year of 2006/07, with ages ranging from 18 to 40 years old. Through a questionnaire, the Astrand Test, and the technique of electric bioimpedance, we obtained the results that allowed us to reach the intended objectives. We used the program Bodygram to obtain the data related to the index of corporal mass and the percentage of fat mass, and the program SPSS, version 14.0, to accomplish the descriptive analysis of the data, a variance analysis and also a correlational analysis. RESULTS: We found evidence that 62.8% of the subjects of the sample presented values of percentage of fat mass above the recommended limits and that 55.7% obtained very low values of VO2max. We also found that 61.7% didn't consider themselves active subjects in what concerns the regular practice of physical activity, and that this variable was correlated with VO2máx. (p=0.01 CONCLUSIONS: We could conclude that most of the subjects of our sample presented low indexes of physical activity, deficient cardiorespiratory capacity and high values in what concerns the percentage of fat mass. The practice of physical activity showed to be positively correlated with the cardiorespiratory capacity. It is necessary to implement more effective campaigns to combat obesity and to sensitize for the regular practice of physical activity and for good eating habits.

  4. Hydrothermal encapsulation of VO2(A) nanorods in amorphous carbon by carbonization of glucose for energy storage devices.

    Science.gov (United States)

    Zheng, Jiqi; Zhang, Yifu; Wang, Qiushi; Jiang, Hanmei; Liu, Yanyan; Lv, Tianming; Meng, Changgong

    2018-01-02

    In recent decades, tremendous attention has been paid to the development of new electrode materials with high capacitance to meet the requirements of electrode materials in supercapacitors. Among vanadium oxides, VO 2 (A) has recently received increasing attention due to its unique layered structure, phase transformation and applications in Li-ion batteries. However, few studies have focused on the electrochemical properties of VO 2 (A) as electrochemical capacitors. Herein, we develop a facile hydrothermal method to prepare VO 2 (A)@C core-shell structured composites by carbonization of glucose in the presence of V 2 O 5 nanowires. The electrochemical properties of the VO 2 (A)@C core-shell composites are investigated as a supercapacitor electrode material for the first time; the composites show excellent pseudocapacitive behavior and display a specific capacitance as high as 179 F g -1 at 1 A g -1 . A flexible asymmetric supercapacitor device is fabricated using VO 2 (A)@C composites and activated carbon and delivers an excellent capacitance of 0.5 F cm -2 at a scan rate of 5 mV s -1 . Replacing the aqueous electrolyte with a LiCl/PVA gel electrolyte can efficiently improve the cycling performance to 85% retention after 1600 cycles. The good electrochemical performance of the composites indicates their high potential as electrode materials for supercapacitors.

  5. Enhanced Visible Transmittance of Thermochromic VO2 Thin Films by SiO2 Passivation Layer and Their Optical Characterization

    Directory of Open Access Journals (Sweden)

    Jung-Hoon Yu

    2016-07-01

    Full Text Available This paper presents the preparation of high-quality vanadium dioxide (VO2 thermochromic thin films with enhanced visible transmittance (Tvis via radio frequency (RF sputtering and plasma enhanced chemical vapor deposition (PECVD. VO2 thin films with high Tvis and excellent optical switching efficiency (Eos were successfully prepared by employing SiO2 as a passivation layer. After SiO2 deposition, the roughness of the films was decreased 2-fold and a denser structure was formed. These morphological changes corresponded to the results of optical characterization including the haze, reflectance and absorption spectra. In spite of SiO2 coating, the phase transition temperature (Tc of the prepared films was not affected. Compared with pristine VO2, the total layer thickness after SiO2 coating was 160 nm, which is an increase of 80 nm. Despite the thickness change, the VO2 thin films showed a higher Tvis value (λ 650 nm, 58% compared with the pristine samples (λ 650 nm, 43%. This enhancement of Tvis while maintaining high Eos is meaningful for VO2-based smart window applications.

  6. Mg-doped VO2 nanoparticles: hydrothermal synthesis, enhanced visible transmittance and decreased metal-insulator transition temperature.

    Science.gov (United States)

    Zhou, Jiadong; Gao, Yanfeng; Liu, Xinling; Chen, Zhang; Dai, Lei; Cao, Chuanxiang; Luo, Hongjie; Kanahira, Minoru; Sun, Chao; Yan, Liuming

    2013-05-28

    This paper reports the successful preparation of Mg-doped VO2 nanoparticles via hydrothermal synthesis. The metal-insulator transition temperature (T(c)) decreased by approximately 2 K per at% Mg. The Tc decreased to 54 °C with 7.0 at% dopant. The composite foils made from Mg-doped VO2 particles displayed excellent visible transmittance (up to 54.2%) and solar modulation ability (up to 10.6%). In addition, the absorption edge blue-shifted from 490 nm to 440 nm at a Mg content of 3.8 at%, representing a widened optical band gap from 2.0 eV for pure VO2 to 2.4 eV at 3.8 at% doping. As a result, the colour of the Mg-doped films was modified to increase their brightness and lighten the yellow colour over that of the undoped-VO2 film. A first principle calculation was conducted to understand how dopants affect the optical, Mott phase transition and structural properties of VO2.

  7. EPR and optical absorption studies of paramagnetic molecular ion (VO2+) in Lithium Sodium Acid Phthalate single crystal

    Science.gov (United States)

    Subbulakshmi, N.; Kumar, M. Saravana; Sheela, K. Juliet; Krishnan, S. Radha; Shanmugam, V. M.; Subramanian, P.

    2017-12-01

    Electron Paramagnetic Resonance (EPR) spectroscopic studies of VO2+ ions as paramagnetic impurity in Lithium Sodium Acid Phthalate (LiNaP) single crystal have been done at room temperature on X-Band microwave frequency. The lattice parameter values are obtained for the chosen system from Single crystal X-ray diffraction study. Among the number of hyperfine lines in the EPR spectra only two sets are reported from EPR data. The principal values of g and A tensors are evaluated for the two different VO2+ sites I and II. They possess the crystalline field around the VO2+ as orthorhombic. Site II VO2+ ion is identified as substitutional in place of Na1 location and the other site I is identified as interstitial location. For both sites in LiNaP, VO2+ are identified in octahedral coordination with tetragonal distortion as seen from the spin Hamiltonian parameter values. The ground state of vanadyl ion in the LiNaP single crystal is dxy. Using optical absorption data the octahedral and tetragonal parameters are calculated. By correlating EPR and optical data, the molecular orbital bonding parameters have been discussed for both sites.

  8. The acidic transformed nano-VO2 causes macrophage cell death by the induction of lysosomal membrane permeabilization and Ca2+ efflux

    Directory of Open Access Journals (Sweden)

    Shaohai Xu

    2015-01-01

    Full Text Available Because of its outstanding thermochromic characteristics and metal-insulator transition (MIT property, nano-vanadium dioxide (abbreviated as nano-VO2 or nVO2 has been applied widely in electrical/optical devices and design of intelligent window. However, the biological effect of nVO2 is not well understood, especially when affected by environmental factors or living organisms. For VO2 is an amphoteric oxide, we simulated pH's influence to nVO2’s physicochemical properties by exposure nVO2 in water of different pH values. We found that nVO2 transformed to a new product after exposure in acidic water for two weeks, as revealed by physicochemical characterization such as SEM, TEM, XRD, and DLS. This transformation product formed in acidic water was referred as (acidic transformed nVO2. Both pristine/untransformed and transformed nVO2 displayed no obvious toxicity to common epithelial cells; however, the acidic transformed nVO2 rapidly induced macrophage cell death. Further investigation demonstrated that transformed nVO2 caused macrophage apoptosis by the induction of Ca2+ efflux and the following mitochondrial membrane permeabilization (MMP process. And a more detailed time course study indicated that transformed nVO2 caused lysosomal membrane permeabilization (LMP at the earlier stage, indicating LMP could be chosen as an earlier and sensitive end point for nanotoxicological study. We conclude that although nVO2 displays no acute toxicity, its acidic transformation product induces macrophage apoptosis by the induction of LMP and Ca2+ efflux. This report suggests that the interplay with environmental factors or living organisms can results in physicochemical transformation of nanomaterials and the ensuing distinctive biological effects.

  9. On one-parametric formula relating the frequencies of twin-peak quasi-periodic oscillations

    Science.gov (United States)

    Török, Gabriel; Goluchová, Kateřina; Šrámková, Eva; Horák, Jiří; Bakala, Pavel; Urbanec, Martin

    2018-01-01

    Twin-peak quasi-periodic oscillations (QPOs) are observed in several low-mass X-ray binary systems containing neutron stars. Timing the analysis of X-ray fluxes of more than dozen of such systems reveals remarkable correlations between the frequencies of two characteristic peaks present in the power density spectra. The individual correlations clearly differ, but they roughly follow a common individual pattern. High values of measured QPO frequencies and strong modulation of the X-ray flux both suggest that the observed correlations are connected to orbital motion in the innermost part of an accretion disc. Several attempts to model these correlations with simple geodesic orbital models or phenomenological relations have failed in the past. We find and explore a surprisingly simple analytic relation that reproduces individual correlations for a group of several sources through a single parameter. When an additional free parameter is considered within our relation, it well reproduces the data of a large group of 14 sources. The very existence and form of this simple relation support the hypothesis of the orbital origin of QPOs and provide the key for further development of QPO models. We discuss a possible physical interpretation of our relation's parameters and their links to concrete QPO models.

  10. Why the Heyd-Scuseria-Ernzerhof hybrid functional description of VO2 phases is not correct

    KAUST Repository

    Grau-Crespo, Ricardo; Schwingenschlö gl, Udo; Wang, Hao

    2012-01-01

    In contrast with recent claims that the Heyd-Scuseria-Ernzerhof (HSE) screened hybrid functional can provide a good description of the electronic and magnetic structures of VO2 phases, we show here that the HSE lowest-energy solutions for both the low-temperature monoclinic (M1) phase and the high-temperature rutile (R) phase, which are obtained upon inclusion of spin polarization, are at odds with experimental observations. For the M1 phase the ground state is (but should not be) magnetic, while the ground state of the R phase, which is also spin polarized, is not (but should be) metallic. The energy difference between the low-temperature and high-temperature phases has strong discrepancies with the experimental latent heat.

  11. Why the Heyd-Scuseria-Ernzerhof hybrid functional description of VO2 phases is not correct

    KAUST Repository

    Grau-Crespo, Ricardo

    2012-08-06

    In contrast with recent claims that the Heyd-Scuseria-Ernzerhof (HSE) screened hybrid functional can provide a good description of the electronic and magnetic structures of VO2 phases, we show here that the HSE lowest-energy solutions for both the low-temperature monoclinic (M1) phase and the high-temperature rutile (R) phase, which are obtained upon inclusion of spin polarization, are at odds with experimental observations. For the M1 phase the ground state is (but should not be) magnetic, while the ground state of the R phase, which is also spin polarized, is not (but should be) metallic. The energy difference between the low-temperature and high-temperature phases has strong discrepancies with the experimental latent heat.

  12. Determinants of time limit at velocity corresponding to VO2max in physically active individuals

    Directory of Open Access Journals (Sweden)

    Jefferson da Silva Novaes

    2008-01-01

    Full Text Available The objective of the present study was to determine the relationship between time limit (Tlim at VO2Máx velocity (VVO2Máx and the variables VO2Máx, VVO2Máx, running economy (RE, ventilatory threshold (VT, strength test (9-10 maximum repetitions, velocity at maximal anaerobic running test (VMART, vertical jump test and body fat percentage. The sample was composed of 18 male volunteers, aged between 18 and 45 years old, non-athletes, but physically active. The study was carried out during fi ve visits, on non-consecutive days and at approximately the same time each day: visit 1 - signature of informed consent form, medical history, anthropometric assessment, aerobic power test and familiarization with Tlim test; visit 2 - RE test and Tlim test; visit 3 - familiarization with VMART test; visit 4 - familiarization with vertical jump and 9-10 maximum repetition tests and VMART test; visit 5 - vertical jump and 9-10 maximum repetition tests. Low (r = 0.220 to – 0.359 and non-significant correlations (p = 0.281 to 0.935 were observed between Tlim and the selected variables, characterizing the low predictive value of Tlim for the sample studied. Thus, and because of the considerable inter-individual variability in Tlim, no variable was identified that was capable of satisfactorily predicting Tlim. Resumo O objetivo do presente estudo foi determinar a relação do tempo limite (Tlim na velocidade do VO2Máx (VVO2Máx com as variáveis VO2Máx, VVO2Máx, economia de corrida (EC, limiar ventilatório (LV, força isotônica (determinada pelo teste de 9-10 RM, velocidade no teste máximo de corrida anaeróbica (VMART, impulsão vertical e percentual de gordura (%G . A amostra foi composta por 18 voluntários do sexo masculino, com idade entre 18 e 45 anos, não atletas, regularmente ativos. O estudo foi realizado em cinco visitas, em dias não consecutivos e aproximadamente no mesmo horário, compostas de: visita 1 - assinatura do termo de

  13. Acoustic excitations in glassy sorbitol and their relation with the fragility and the boson peak

    Science.gov (United States)

    Ruta, B.; Baldi, G.; Scarponi, F.; Fioretto, D.; Giordano, V. M.; Monaco, G.

    2012-12-01

    We report a detailed analysis of the dynamic structure factor of glassy sorbitol by using inelastic X-ray scattering and previously measured light scattering data [B. Ruta, G. Monaco, F. Scarponi, and D. Fioretto, Philos. Mag. 88, 3939 (2008), 10.1080/14786430802317586]. The thus obtained knowledge on the density-density fluctuations at both the mesoscopic and macroscopic length scale has been used to address two debated topics concerning the vibrational properties of glasses. The relation between the acoustic modes and the universal boson peak (BP) appearing in the vibrational density of states of glasses has been investigated, also in relation with some recent theoretical models. Moreover, the connection between the elastic properties of glasses and the slowing down of the structural relaxation process in supercooled liquids has been scrutinized. For what concerns the first issue, it is here shown that the wave vector dependence of the acoustic excitations can be used, in sorbitol, to quantitatively reproduce the shape of the boson peak, supporting the relation between BP and acoustic modes. For what concerns the second issue, a proper study of elasticity over a wide spatial range is shown to be fundamental in order to investigate the relation between elastic properties and the slowing down of the dynamics in the corresponding supercooled liquid phase.

  14. Excitations and possible bound states in the S = 1/2 alternating chain compound (VO)2P2O7

    International Nuclear Information System (INIS)

    Tennant, D.A.; Nagler, S.E.; Sales, B.C.

    1997-01-01

    Magnetic excitations in an array of (VO) 2 P 2 O 7 single crystals have been measured using inelastic neutron scattering. Until now, (VO) 2 P 2 O 7 has been thought of as a two-leg antiferromagnetic Heisenberg spin ladder with chains running in the a-direction. The present results show unequivocally that (VO) 2 P 2 O 7 is best described as an alternating spin-chain directed along the crystallographic b-direction. In addition to the expected magnon with magnetic zone-center energy gap Δ = 3.1 meV, a second excitation is observed at an energy just below 2Δ. The higher mode may be a triplet two-magnon bound state. Numerical results in support of bound modes are presented

  15. EPR and optical absorption studies of VO2+ doped L-alanine (C3H7NO2) single crystals

    International Nuclear Information System (INIS)

    Biyik, Recep

    2009-01-01

    VO 2+ doped L-alanine (C 3 H 7 NO 2 ) single crystals and powders are examined by electron paramagnetic resonance (EPR) and optical absorption spectroscopy. Three magnetically different sites are resolved from angular variations of L-alanine single crystal EPR spectra. In some specific orientations each VO 2+ line splits into three superhyperfine lines with intensities of 1:2:1 and maximum splitting value of 2.23 mT. The local symmetries of VO 2+ complex sites are nearly axial. The optical absorption spectra show three bands. Spin Hamiltonian parameters are measured and molecular orbital coefficients are calculated by correlating EPR and optical absorption data for the central vanadyl ion.

  16. Plasma volume expansion does not increase maximal cardiac output or VO2 max in lowlanders acclimatized to altitude

    DEFF Research Database (Denmark)

    Calbet, José A L; Rådegran, Göran; Boushel, Robert Christopher

    2004-01-01

    liter of 6% dextran 70 (BV = 6.32 +/- 0.34 liters). PV expansion had no effect on Qmax, maximal O2 consumption (VO2), and exercise capacity. Despite maximal systemic O2 transport being reduced 19% due to hemodilution after PV expansion, whole body VO2 was maintained by greater systemic O2 extraction (P...... VO2 during exercise regardless of PV. Pulmonary ventilation, gas exchange, and acid-base balance were essentially unaffected by PV expansion. Sea......With altitude acclimatization, blood hemoglobin concentration increases while plasma volume (PV) and maximal cardiac output (Qmax) decrease. This investigation aimed to determine whether reduction of Qmax at altitude is due to low circulating blood volume (BV). Eight Danish lowlanders (3 females, 5...

  17. Sharpness and intensity modulation of the metal-insulator transition in ultrathin VO2 films by interfacial structure manipulation

    Science.gov (United States)

    McGee, Ryan; Goswami, Ankur; Pal, Soupitak; Schofield, Kalvin; Bukhari, Syed Asad Manzoor; Thundat, Thomas

    2018-03-01

    Vanadium dioxide (VO2) undergoes a structural transformation from monoclinic (insulator) to tetragonal (metallic) upon heating above 340 K, accompanied by abrupt changes to its electronic, optical, and mechanical properties. Not only is this transition scientifically intriguing, but there are also numerous applications in sensing, memory, and optoelectronics. Here we investigate the effect different substrates and the processing conditions have on the characteristics metal-insulator transition (MIT), and how the properties can be tuned for specific applications. VO2 thin films were grown on c -plane sapphire (0001) and p-type silicon by pulsed laser deposition. High-resolution x-ray diffraction along with transmission electron microscopy reveals textured epitaxial growth on sapphire by domain-matching epitaxy, while the presence of a native oxide layer on silicon prevented any preferential growth resulting in a polycrystalline film. An orientation relationship of (010)VO2|| (0001)Al 2O3 was established for VO2 grown on sapphire, while no such relationship was found for VO2 grown on silicon. Surface-energy minimization is the driving force behind grain growth, as the lowest energy VO2 plane grew on silicon, while on sapphire the desire for epitaxial growth was dominant. Polycrystallinity of films grown on silicon caused a weaker and less prominent MIT than observed on sapphire, whose MIT was higher in magnitude and steeper in slope. The position of the MIT was shown to depend on the competing effects of misfit strain and grain growth. Higher deposition temperatures caused an increase in the MIT, while compressive strain resulted in a decreased MIT.

  18. Metal-Insulator Phase Transition in thin VO2 films: A Look from the Far Infrared Side

    DEFF Research Database (Denmark)

    Jepsen, Peter Uhd; Fischer, B. M.; Thoman, A.

    Vanadium dioxide (VO2) displays a well-known metal-insulator (MI) transition at atemperature of 68oC. The MI transition in VO2 has been studied extensively by a widerange of optical, electrical, structural, and magnetic measurements. In spite of this there isstill some controversy about the nature...... temperature hysteresis of the far-infrared transmission through thethin film with temperature. Interestingly the temperature-dependent transmissionamplitude shows a markedly different switching temperature than the transmission phase.This effect has not been observed before, and is very important...

  19. ARTICLES: Nonlinear interaction of infrared waves on a VO2 surface at a semiconductor-metal phase transition

    Science.gov (United States)

    Berger, N. K.; Zhukov, E. A.; Novokhatskiĭ, V. V.

    1984-04-01

    The use of a semiconductor-metal phase transition for wavefront reversal of laser radiation was proposed. An investigation was made of nonlinear reflection of CO2 laser radiation at a phase transition in VO2. A three-wave interaction on a VO2 surface was achieved using low-power cw and pulsed CO2 lasers. In the first case, the intensity reflection coefficient was 0.5% for a reference wave intensity of 0.9 W/cm2 and in the second case, it was 42% for a threshold reference wave energy density of 0.6-0.8 mJ/cm2.

  20. Preparation and modification of VO2 thin film on R-sapphire substrate by rapid thermal process

    Science.gov (United States)

    Zhu, Nai-Wei; Hu, Ming; Xia, Xiao-Xu; Wei, Xiao-Ying; Liang, Ji-Ran

    2014-04-01

    The VO2 thin film with high performance of metal-insulator transition (MIT) is prepared on R-sapphire substrate for the first time by magnetron sputtering with rapid thermal process (RTP). The electrical characteristic and THz transmittance of MIT in VO2 film are studied by four-point probe method and THz time domain spectrum (THz-TDS). X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and search engine marketing (SEM) are employed to analyze the crystalline structure, valence state, surface morphology of the film. Results indicate that the properties of VO2 film which is oxidized from the metal vanadium film in oxygen atmosphere are improved with a follow-up RTP modification in nitrogen atmosphere. The crystallization and components of VO2 film are improved and the film becomes compact and uniform. A better phase transition performance is shown that the resistance changes nearly 3 orders of magnitude with a 2-°C hysteresis width and the THz transmittances are reduced by 64% and 60% in thermal and optical excitation respectively.

  1. Voltage- and current-activated metal–insulator transition in VO2-based electrical switches: a lifetime operation analysis

    Directory of Open Access Journals (Sweden)

    Aurelian Crunteanu, Julien Givernaud, Jonathan Leroy, David Mardivirin, Corinne Champeaux, Jean-Christophe Orlianges, Alain Catherinot and Pierre Blondy

    2010-01-01

    Full Text Available Vanadium dioxide is an intensively studied material that undergoes a temperature-induced metal–insulator phase transition accompanied by a large change in electrical resistivity. Electrical switches based on this material show promising properties in terms of speed and broadband operation. The exploration of the failure behavior and reliability of such devices is very important in view of their integration in practical electronic circuits. We performed systematic lifetime investigations of two-terminal switches based on the electrical activation of the metal–insulator transition in VO2 thin films. The devices were integrated in coplanar microwave waveguides (CPWs in series configuration. We detected the evolution of a 10 GHz microwave signal transmitted through the CPW, modulated by the activation of the VO2 switches in both voltage- and current-controlled modes. We demonstrated enhanced lifetime operation of current-controlled VO2-based switching (more than 260 million cycles without failure compared with the voltage-activated mode (breakdown at around 16 million activation cycles. The evolution of the electrical self-oscillations of a VO2-based switch induced in the current-operated mode is a subtle indicator of the material properties modification and can be used to monitor its behavior under various external stresses in sensor applications.

  2. Phase transition in LiVO2 studied by near-edge x-ray-absorption spectroscopy

    NARCIS (Netherlands)

    Pen, HF; Tjeng, LH; Pellegrin, E; deGroot, FMF; Sawatzky, GA; vanVeenendaal, MA; Chen, CT

    1997-01-01

    We present temperature-dependent V-2p and O-1s x-ray-absorption spectra of LiVO2. The aim of this study is to monitor changes in electronic structure on going through the phase transition. The spectral changes turn out to be very small: the V-3d-O-2p hybridization does not change considerably, and

  3. Efeito da intensidade do exercício de corrida intermitente 30s:15s no tempo de manutenção no ou próximo do VO2max Effect of intensity of intermittent running exercise 30s:15s at the time maintenance at or near VO2max

    Directory of Open Access Journals (Sweden)

    Rafael Alves de Aguiar

    2013-03-01

    Full Text Available O presente estudo comparou o tempo mantido acima de 90% (t90VO2max e de 95% VO2max (t95VO2max em três diferentes intensidades de exercício. Após a realização de um teste incremental para determinar o VO2max, oito estudantes de educação física ativos (23 ± 3 anos executaram três sessões de exercícios intermitentes (100, 110 e 120% da velocidade do VO2max (vVO2max com razão esforço:recuperação de 30s:15s. O t95VO2max foi significantemente maior em 110%vVO2max (EI110% (218,1 ± 81,6 s quando comparado a 100%vVO2max (EI100% (91,9 ± 75,2s e a 120%vVO2max (EI120% (126,3 ± 29,4 s, porém sem diferença entre EI100% e EI120%. O t90VO2max somente apresentou diferença significante entre EI110% e EI120%. Portanto, conclui-se que durante exercício intermitente com razão 30s:15s, a intensidade de 110%vVO2max apresenta-se mais adequada para manter o VO2 próximo ou no VO2max por um tempo maior.The present study compared the time maintained above 90% (t90VO2max or 95% VO2max (t95VO2max in three different exercise intensities. After performing an incremental test to determine VO2max, eight physical education active students (23 ± 3 years performed three intermittent exercise sessions (100, 110 e 120% velocity of VO2max (vVO2max with ratio effort:recovery of 30s:15s. The t95%VO2max was significantly higher at 110%vVO2max (EI110% (218.1 ± 81.6s compared to 100% vVO2max (EI100% (91.9 ± 75.2s and 120%vVO2max (EI120% (126.3 ± 29.4s, but without differences between EI100% and EI120%. The t90%vVO2max was significantly different only between EI110% and 120%. Therefore, we conclude that during intermittent exercise with ratio 30s:15s, the intensity of 110%vVO2max appears more appropriate to maintain VO2max for a longer time.

  4. Endurance training increases exercise-induced prostacyclin release in young, healthy men--relationship with VO2max.

    Science.gov (United States)

    Zoladz, Jerzy A; Majerczak, Joanna; Duda, Krzysztof; Chłopicki, Stefan

    2010-01-01

    In the present study, we evaluated the effect of 5 weeks of moderate-intensity endurance training on the basal and exercise-induced systemic release of prostacyclin (PGI(2)), as assessed by plasma 6-keto-PGF(1 alpha) concentration. Twelve physically active young men with the following characteristics participated in this study (the mean +/- SD): age, 22.7 +/- 2.0 years; body mass, 76.8 +/- 8.9 kg; BMI, 23.48 +/- 2.17 kg x m(-2); and maximal oxygen uptake (VO(2 max)), 46.1 +/- 4.0 ml x kg(-1) x min(-1). Plasma 6-keto-PGF(1 alpha) concentrations were measured in venous blood samples taken prior to the exercise and at exhaustion (at VO(2 max)) before and after completing the training protocol. On average, the training resulted in a significant increase in VO(2 max) (p = 0.03), power output at VO(2 max) (p = 0.001) and a significant increase (p = 0.05) in the net-exercise-induced increase in plasma 6-keto-PGF(1 alpha) concentration (Delta 6-keto-PGF(1 alpha) i.e., the difference between the end-exercise and pre-exercise 6-keto-PGF(1 alpha) concentrations). No effect of training on the basal PGI(2) concentration was found. Interestingly, within the study sample (n = 12), two subgroups could be defined with a differential pattern of response with respect to Delta 6-keto-PGF(1 alpha) concentrations. In one subgroup (n = 7), a significant increase in Delta 6-keto-PGF(1 alpha) concentration after training was found (p < 0.02) (responders). This enhancement in the exercise-induced PGI(2) release was accompanied by a significant (p < 0.05) increase in VO(2 max) after training. In contrast, in another subgroup (n = 5), there was no observed effect of training on the Delta 6-keto-PGF(1 alpha) concentration and the VO(2 max) after training (non-responders). In both of these subgroups, training did not influence the basal PGI(2) concentration. In conclusion, the endurance training resulted in the adaptive augmentation of the systemic release of PGI(2) in response to exercise

  5. Effects of V2O3 buffer layers on sputtered VO2 smart windows: Improved thermochromic properties, tunable width of hysteresis loops and enhanced durability

    Science.gov (United States)

    Long, Shiwei; Cao, Xun; Sun, Guangyao; Li, Ning; Chang, Tianci; Shao, Zewei; Jin, Ping

    2018-05-01

    Vanadium dioxide (VO2) is one of the most well-known thermochromic materials, which exhibits a notable optical change from transparent to reflecting in the infrared region upon a metal-insulator phase transition. For practical applications, VO2 thin films should be in high crystalline quality to obtain a strong solar modulation ability (ΔTsol). Meanwhile, narrow hysteresis loops and robust ambient durability are also indispensable for sensitivity and long-lived utilization, respectively. In this work, a series of high-quality V2O3/VO2 bilayer structures were grown on quartz glass substrates by reactive magnetron sputtering. Basically, the bottom V2O3 acts as the buffer layer to improve the crystallinity of the top VO2, while the VO2 serves as the thermochromic layer to guarantee the solar modulation ability for energy-saving. We observed an obvious increase in ΔTsol of 76% (from 7.5% to 13.2%) for VO2 films after introducing V2O3 buffer layers. Simultaneously, a remarkable reduction by 79% (from 21.9 °C to 4.7 °C) in width of hysteresis loop was obtained when embedding 60 nm V2O3 buffer for 60 nm VO2. In addition, VO2 with non-stoichiometry of V2O3±x buffer demonstrates a broadening hysteresis loops width, which is derived from the lattice distortion caused by lattice imperfection. Finally, durability of VO2 has been significantly improved due to positive effects of V2O3 buffer layer. Our results lead to a comprehensive enhancement in crystallinity of VO2 and shed new light on the promotion of thermochromic property by homologous oxides for VO2.

  6. Effectiveness of High-Intensity Interval Training (HIT) and Continuous Endurance Training for VO2max Improvements: A Systematic Review and Meta-Analysis of Controlled Trials.

    Science.gov (United States)

    Milanović, Zoran; Sporiš, Goran; Weston, Matthew

    2015-10-01

    Enhancing cardiovascular fitness can lead to substantial health benefits. High-intensity interval training (HIT) is an efficient way to develop cardiovascular fitness, yet comparisons between this type of training and traditional endurance training are equivocal. Our objective was to meta-analyse the effects of endurance training and HIT on the maximal oxygen consumption (VO2max) of healthy, young to middle-aged adults. Six electronic databases were searched (MEDLINE, PubMed, SPORTDiscus, Web of Science, CINAHL and Google Scholar) for original research articles. A search was conducted and search terms included 'high intensity', 'HIT', 'sprint interval training', 'endurance training', 'peak oxygen uptake', and 'VO2max'. Inclusion criteria were controlled trials, healthy adults aged 18-45 years, training duration ≥2 weeks, VO2max assessed pre- and post-training. Twenty-eight studies met the inclusion criteria and were included in the meta-analysis. This resulted in 723 participants with a mean ± standard deviation (SD) age and initial fitness of 25.1 ± 5 years and 40.8 ± 7.9 mL·kg(-1)·min(-1), respectively. We made probabilistic magnitude-based inferences for meta-analysed effects based on standardised thresholds for small, moderate and large changes (0.2, 0.6 and 1.2, respectively) derived from between-subject SDs for baseline VO2max. The meta-analysed effect of endurance training on VO2max was a possibly large beneficial effect (4.9 mL·kg(-1)·min(-1); 95 % confidence limits ±1.4 mL·kg(-1)·min(-1)), when compared with no-exercise controls. A possibly moderate additional increase was observed for typically younger subjects (2.4 mL·kg(-1)·min(-1); ±2.1 mL·kg(-1)·min(-1)) and interventions of longer duration (2.2 mL·kg(-1)·min(-1); ±3.0 mL·kg(-1)·min(-1)), and a small additional improvement for subjects with lower baseline fitness (1.4 mL·kg(-1)·min(-1); ±2.0 mL·kg(-1)·min(-1)). When compared with no-exercise controls

  7. Effects of chronic nitric oxide synthase inhibition on V'O2max and exercise capacity in mice.

    Science.gov (United States)

    Wojewoda, M; Przyborowski, K; Sitek, B; Zakrzewska, A; Mateuszuk, L; Zoladz, J A; Chlopicki, S

    2017-03-01

    Acute inhibition of NOS by L-NAME (N ω -nitro-L-arginine methyl ester) is known to decrease maximal oxygen consumption (V'O 2max ) and impair maximal exercise capacity, whereas the effects of chronic L-NAME treatment on V'O 2max and exercise performance have not been studied so far. In this study, we analysed the effect of L-NAME treatment, (LN2 and LN12, respectively) on V'O 2max and exercise capacity (in maximal incremental running and prolonged sub-maximal incremental running tests), systemic NO bioavailability (plasma nitrite (NO 2 - ) and nitrate (NO 3 - )) and prostacyclin (PGI 2 ) production in C57BL6/J mice. Mice treated with L-NAME for 2 weeks (LN2) displayed higher V'O 2max and better running capacity than age-matched control mice. In LN2 mice, NO bioavailability was preserved, as evidenced by maintained NO 2 - plasma concentration. PGI 2 production was activated (increased 6-keto-PGF 1α plasma concentration) and the number of circulating erythrocytes (RBC) and haemoglobin concentration were increased. In mice treated with L-NAME for 12 weeks (LN12), NO bioavailability was decreased (lower NO 2 - plasma concentration), and 6-keto-PGF 1α plasma concentration and RBC number were not elevated compared to age-matched control mice. However, LN12 mice still performed better during the maximal incremental running test despite having lower V'O 2max . Interestingly, the LN12 mice showed poorer running capacity during the prolonged sub-maximal incremental running test. To conclude, short-term (2 weeks) but not long-term (12 weeks) treatment with L-NAME activated robust compensatory mechanisms involving preservation of NO2- plasma concentration, overproduction of PGI 2 and increased number of RBCs, which might explain the fully preserved exercise capacity despite the inhibition of NOS.

  8. Possible factors determining the non-linearity in the VO2-power output relationship in humans: theoretical studies.

    Science.gov (United States)

    Korzeniewski, Bernard; Zoladz, Jerzy A

    2003-08-01

    At low power output exercise (below lactate threshold), the oxygen uptake increases linearly with power output, but at high power output exercise (above lactate threshold) some additional oxygen consumption causes a non-linearity in the overall VO(2) (oxygen uptake rate)-power output relationship. The functional significance of this phenomenon for human exercise tolerance is very important, but the mechanisms underlying it remain unknown. In the present work, a computer model of oxidative phosphorylation in intact skeletal muscle developed previously is used to examine the background of this relationship in different modes of exercise. Our simulations demonstrate that the non-linearity in the VO(2)-power output relationship and the difference in the magnitude of this non-linearity between incremental exercise mode and square-wave exercise mode (constant power output exercise) can be generated by introducing into the model some hypothetical factor F (group of associated factors) that accumulate(s) in time during exercise. The performed computer simulations, based on this assumption, give proper time courses of changes in VO(2) and [PCr] after an onset of work of different intensities, including the slow component in VO(2), well matching the experimental results. Moreover, if it is assumed that the exercise terminates because of fatigue when the amount/intensity of F exceed some threshold value, the model allows the generation of a proper shape of the well-known power-duration curve. This fact suggests that the phenomenon of the non-linearity of the VO(2)-power output relationship and the magnitude of this non-linearity in different modes of exercise is determined by some factor(s) responsible for muscle fatigue.

  9. Predicted VO2max and effectiveness of external chest compression by Chinese nurses.

    Science.gov (United States)

    Ho, Leo S T; Jones, Alice Y M; Rainer, Timothy H

    2017-08-01

    The aims of this study were to assess the influence of sex and body position on external chest compression (ECC) to a manikin by Chinese nurses and to determine the relationship between rescuer's predicted VO2max and ECC depth. A total of 40 nurses performed ECC on a manikin for 5 min in the standing (S) and bed-mount kneeling (K) position, then completed a Chester step-test, in 3 separate days. The rate and depth of compressions and oxygen consumption during ECC were measured. Mean compression rate recorded was above 100/min in both positions throughout ECC. Mean compression depth for male participants was more than 38 mm for 5 min in the K-position but only 3 min in the S-position. Female participants achieved this compression depth for less than 90 s in the K-position but not at all in the S-position. Irrespective of sex, the K-position appears to facilitate effective ECC. The relationship between aerobic fitness of female nurses and their ability to perform effective cardiopulmonary resuscitation warrants further investigation.

  10. Modeling of thermal coupling in VO2-based oscillatory neural networks

    Science.gov (United States)

    Velichko, Andrey; Belyaev, Maksim; Putrolaynen, Vadim; Perminov, Valentin; Pergament, Alexander

    2018-01-01

    In this study, we have demonstrated the possibility of using the thermal coupling to control the dynamics of operation of coupled VO2 oscillators. Based on the example of a 'switch-microheater' pair, we have explored the synchronization and dissynchronization modes of a single oscillator with respect to an external harmonic heat impact. The features of changes in the spectra are shown, in particular, the effect of the natural frequency attraction to the affecting signal frequency and the self-oscillation noise reduction effects at synchronization. The time constant of the temperature effect for the considered system configuration is in the range 7-140 μs, which allows operation in the oscillation frequency range of up to ∼70 kHz. A model estimate of the minimum temperature sensitivity of the switch is δTswitch ∼ 0.2 K, and the effective action radius RTC of the switch-to-switch thermal coupling is not less than 25 μm. Nevertheless, as the simulation shows, the frequency range can be significantly extended up to the values of 1-30 GHz if using nanometer-scale switches (heaters). article>

  11. Hydrogen Treatment for Superparamagnetic VO2 Nanowires with Large Room-Temperature Magnetoresistance.

    Science.gov (United States)

    Li, Zejun; Guo, Yuqiao; Hu, Zhenpeng; Su, Jihu; Zhao, Jiyin; Wu, Junchi; Wu, Jiajing; Zhao, Yingcheng; Wu, Changzheng; Xie, Yi

    2016-07-04

    One-dimensional (1D) transition metal oxide (TMO) nanostructures are actively pursued in spintronic devices owing to their nontrivial d electron magnetism and confined electron transport pathways. However, for TMOs, the realization of 1D structures with long-range magnetic order to achieve a sensitive magnetoelectric response near room temperature has been a longstanding challenge. Herein, we exploit a chemical hydric effect to regulate the spin structure of 1D V-V atomic chains in monoclinic VO2 nanowires. Hydrogen treatment introduced V(3+) (3d(2) ) ions into the 1D zigzag V-V chains, triggering the formation of ferromagnetically coupled V(3+) -V(4+) dimers to produce 1D superparamagnetic chains and achieve large room-temperature negative magnetoresistance (-23.9 %, 300 K, 0.5 T). This approach offers new opportunities to regulate the spin structure of 1D nanostructures to control the intrinsic magnetoelectric properties of spintronic materials. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. F-doped VO2 nanoparticles for thermochromic energy-saving foils with modified color and enhanced solar-heat shielding ability.

    Science.gov (United States)

    Dai, Lei; Chen, Shi; Liu, Jianjun; Gao, Yanfeng; Zhou, Jiadong; Chen, Zhang; Cao, Chuanxiang; Luo, Hongjie; Kanehira, Minoru

    2013-07-28

    F-doped VO2 (M1) nanoparticles were prepared via one-pot hydrothermal synthesis. The F-doping can minimise the size of the VO2 (M1) nanoparticles, induce a homogeneous size distribution and effectively decrease the phase transition temperature to 35 °C at 2.93% F in VO2. VO2 smart glass foils obtained by casting these nanoparticles exhibit excellent thermochromism in the near-infrared region, which suggests that these foils can be used for energy-efficient glass. Compared to a pure VO2 foil, the 2.93% F-doped VO2 foil exhibits an increased solar-heat shielding ability (35.1%) and a modified comfortable colour, while still retaining an excellent solar modulation ability (10.7%) and an appropriate visible transmittance (48.7%). The F-doped VO2 foils are the first to simultaneously meet the requirements of a reduced phase transition temperature, diluted colour and excellent thermochromic properties, and these properties make the further improved F-doped VO2 foils suitable for commercial applications in energy efficient glass.

  13. Relative role of bed roughness change and bed erosion on peak discharge increase in hyperconcentrated floods

    NARCIS (Netherlands)

    Li, W.; Wang, Z.B.; Van Maren, D.S.; De Vriend, H.J.; Wu, B.S.

    2014-01-01

    River floods are usually featured by a downstream flattening discharge peak whereas a downstream increasing discharge peak is observed at a rate exceeding the tributary discharge during highly silt-laden floods (hyperconcentrated floods) in China’s Yellow River. It entails a great challenge in the

  14. 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.

  15. Changes in Running Economy, Respiratory Exchange Ratio and VO2max in Runners following a 10-day Altitude Training Camp.

    Science.gov (United States)

    Diebel, Sebastian R; Newhouse, Ian; Thompson, David S; Johnson, Vineet B K

    2017-01-01

    Running economy (RE) and VO 2 max are important predictors of endurance performance for elite and semi-elite endurance athletes, with RE being an appropriate predictor in a homogenous running population. Altitude training has been observed to change RE (mL.kg -1 .min -1 ), and VO 2 max due to alterations resulting from acclimatization. This study tracked changes in RE and VO 2 max before and after a 10-day altitude training camp at 1828 meters. VO 2 max, RE expressed calorically, and respiratory exchange ratio (RER), were measured below anaerobic threshold (AT) to observe differences between pre-and post-altitude training. Eight varsity cross-country runners between the ages of 18 and 22 years performed an incremental treadmill test, pre- and post-10-day altitude training. Paired samples t-tests were used to statistically analyze the data. Average RE (VO 2 mL.kg -1 .min -1 ) improved following altitude intervention ( M = 56.44 ± 4.28) compared to pre-altitude training (61.30 ± 7.56). These differences were statistically significant t ( 7 )= 2.71, p =.014. RE expressed as kcals.kg -1 .km -1 improved following altitude training (16.73 ± 2.96) compared to (18.44 ± 4.04) pre-altitude training and was statistically significant t( 7 ) =3.08, p = .008. RER taken during the last minute of steady-state was higher (0.97, ± .019) post-altitude training, compared to (0.90 ± .043) pre-altitude. These differences were statistically significant t ( 7 ) -3.62, p =.008. VO 2 max (mL.kg -1 .min -1 ) was lower in 6 out of 8 participants (63.91, ± 8.65) post-altitude compared to (69.90, ± 10.80) pre-altitude and was statistically significant t( 7 ) = 2.33, p =.026. The observed improvements in RE may be beneficial for endurance athletes competing and/or training at moderate altitudes near 1828 meters.

  16. Spanish genetic admixture is associated with larger V(O2) max decrement from sea level to 4338 m in Peruvian Quechua.

    Science.gov (United States)

    Brutsaert, Tom D; Parra, Esteban J; Shriver, Mark D; Gamboa, Alfredo; Palacios, Jose-Antonio; Rivera, Maria; Rodriguez, Ivette; León-Velarde, Fabiola

    2003-08-01

    Quechua in the Andes may be genetically adapted to altitude and able to resist decrements in maximal O2 consumption in hypoxia (DeltaVo2 max). This hypothesis was tested via repeated measures of Vo2 max (sea level vs. 4338 m) in 30 men of mixed Spanish and Quechua origins. Individual genetic admixture level (%Spanish ancestry) was estimated by using ancestry-informative DNA markers. Genetic admixture explained a significant proportion of the variability in DeltaVo2 max after control for covariate effects, including sea level Vo2 max and the decrement in arterial O2 saturation measured at Vo2 max (DeltaSpO2 max) (R2 for admixture and covariate effects approximately 0.80). The genetic effect reflected a main effect of admixture on DeltaVo2 max (P = 0.041) and an interaction between admixture and DeltaSpO2 max (P = 0.018). Admixture predicted DeltaVo2 max only in subjects with a large DeltaSpO2 max (P = 0.031). In such subjects, DeltaVo2 max was 12-18% larger in a subgroup of subjects with high vs. low Spanish ancestry, with least squares mean values (+/-SE) of 739 +/- 71 vs. 606 +/- 68 ml/min, respectively. A trend for interaction (P = 0.095) was also noted between admixture and the decrease in ventilatory threshold at 4338 m. As previously, admixture predicted DeltaVo2 max only in subjects with a large decrease in ventilatory threshold. These findings suggest that the genetic effect on DeltaVo2 max depends on a subject's aerobic fitness. Genetic effects may be more important (or easier to detect) in athletic subjects who are more likely to show gas-exchange impairment during exercise. The results of this study are consistent with the evolutionary hypothesis and point to a better gas-exchange system in Quechua.

  17. Objectively measured daily physical activity related to aerobic fitness in young children

    DEFF Research Database (Denmark)

    Dencker, Magnus; Bugge, Anna; Hermansen, Bianca

    2010-01-01

    The purpose of this study was to investigate by direct measurement the cross-sectional relationship between accelerometer-measured physical activity and peak oxygen uptake (VO(2peak): ml x min(-1) x kg(-1)), in a population-based cohort of young children, since such data are scarce. The study...... analyses indicated that the various physical activity variables explained between 2 and 8% of the variance in VO(2peak) in boys. In this population-based cohort, most daily activity variables were positively related to aerobic fitness in boys, whereas less clear relationships were observed in girls. Our...... finding that physical activity was only uniformly related to aerobic fitness in boys partly contradicts previous studies in older children and adolescents....

  18. 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

  19. Contribution of central and peripheral factors at peak exercise in heart failure patients with progressive severity of exercise limitation.

    Science.gov (United States)

    Del Torto, Alberico; Corrieri, Nicoletta; Vignati, Carlo; Gentile, Piero; Cattadori, Gaia; Paolillo, Stefania; Agostoni, Piergiuseppe

    2017-12-01

    A reduced cardiac output (CO) response during exercise is a major limiting factor in heart failure (HF). Oxygen consumption (VO 2 ) is directly proportional to CO. Peripheral mechanisms via arteriovenous oxygen difference (Δ(a-v)O 2 ) play a pivotal role in chronic HF. We hypothesized a weak correlation between peak VO 2 and peak CO with a greater Δ(a-v)O 2 variability in most severe HF. We analyzed 278 HF patients (NYHA II-III) who performed maximal cardiopulmonary exercise test with non-invasive CO measurement by inert gas rebreathing. Median peakVO 2 , CO and Δ(a-v)O 2 were 0.96 (0.78-1.28) L/min, 6.3 (5.1-8.0) L/min and 16.0 (14.2-18.0) mL/100mL respectively, with a linear relationship between VO 2 and CO: CO=5.3×VO 2 +1.13 (r 2 =0.705, pexercise limitation. Group 1 (101 patients) peakVO 2 <50% pred: peakVO 2 0.80 (0.67-0.94) L/min, peakCO 5.6 (4.7-6.5) L/min, peakΔ(a-v)O 2 14.8 (12.9-17.1) mL/100mL. Group 2 (89 patients) peakVO 2 ≥50-<65% pred: peakVO 2 1.02 (0.84-1.29) L/min, peakCO 6.4 (5.1-8.0) L/min, peakΔ(a-v)O 2 16.7 (15.0-18.5) mL/100mL. Group 3 (88 patients) peakVO 2 ≥65% pred: peakVO 2 1.28 (0.93-1.66) L/min, peakCO 8.0 (6.2-9.7) L/min, peakΔ(a-v)O 2 16.8 (14.6-18.3) mL/100mL. A peakVO 2 and peakCO linear relationship was observed in Group 1 (r 2 =0.381, p<0.001), Group 2 (r 2 =0.756, p<0.001) and Group 3 (r 2 =0.744, p<0.001). With worsening HF we observed a progressive reduction of peak CO and peak VO 2 . However in most compromised patients also peripheral mechanisms play a role as indicated by reduced Δ(a-v)O 2 . Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Bidirectional current triggering in planar devices based on serially connected VO2 thin films using 965 nm laser diode.

    Science.gov (United States)

    Kim, Jihoon; Park, Kyongsoo; Kim, Bong-Jun; Lee, Yong Wook

    2016-08-08

    By incorporating a 965 nm laser diode, the bidirectional current triggering of up to 30 mA was demonstrated in a two-terminal planar device based on serially connected vanadium dioxide (VO2) thin films grown by pulsed laser deposition. The bidirectional current triggering was realized by using the focused beams of laser pulses through the photo-thermally induced phase transition of VO2. The transient responses of laser-triggered currents were also investigated when laser pulses excited the device at a variety of pulse widths and repetition rates of up to 4.0 Hz. A switching contrast between off- and on-state currents was obtained as ~8333, and rising and falling times were measured as ~39 and ~29 ms, respectively, for 50 ms laser pulses.

  1. Thickness dependence of optical properties of VO2 thin films epitaxially grown on sapphire (0 0 0 1)

    International Nuclear Information System (INIS)

    Xu Gang; Jin Ping; Tazawa, Masato; Yoshimura, Kazuki

    2005-01-01

    Vanadium dioxide (VO 2 ) films were epitaxially grown on α-Al 2 O 3 (0 0 0 1) by rf reactive magnetron sputtering. The effects of film thickness ranging from 3 to 150 nm on optical properties were investigated. It revealed that the semiconductor--metal phase transition temperature considerably decreases as film thickness decreases, in particular for the film with thickness less than 10 nm. On the other hand, we found that the difference in visible transmittance between the two phases of VO 2 also varies with film thickness. For the films with thickness less than 50 nm, the semiconductor phase exhibits lower visible transmittance than its metallic phase, while for those with thickness larger than 50 nm the situation is reversed

  2. High-Impact Aerobic and Zumba Fitness on Increasing VO2MAX, Heart Rate Recovery and Skinfold Thickness

    Science.gov (United States)

    Suminar, T. J.; Kusnanik, N. W.; Wiriawan, O.

    2018-01-01

    Purpose of this study is to determine the significant effect of high-impact aerobics exercise, and Zumba fitness on increasing VO2Max, decreasing of heart rate recovery, and decreasing of skinfold thickness. A sample of this study is 30 members aerobics of student activity unit. Type of this study was quantitative by using a quasi-experimental design method. The design of this study used Matching-Only Design. Data were Analyzed by using the t test (paired t-test). The samples divided into three groups consisted of experimental group I, experimental group II, and control group. They were given a treatment for 8 weeks or 24 meeting. For the data, retrieval is done by MFT test, heart rate recovery test, and skinfold thickness test. Furthermore, the result was analyzed by using SPSS 21 series. In conclusion, significant effect of high-impact aerobics and Zumba fitness on increasing VO2Max, heart rate recovery, skinfold thickness.

  3. VO2 Thermochromic Films on Quartz Glass Substrate Grown by RF-Plasma-Assisted Oxide Molecular Beam Epitaxy

    Directory of Open Access Journals (Sweden)

    Dong Zhang

    2017-03-01

    Full Text Available Vanadium dioxide (VO2 thermochromic thin films with various thicknesses were grown on quartz glass substrates by radio frequency (RF-plasma assisted oxide molecular beam epitaxy (O-MBE. The crystal structure, morphology and chemical stoichiometry were investigated systemically by X-ray diffraction (XRD, atomic force microscopy (AFM, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS analyses. An excellent reversible metal-to-insulator transition (MIT characteristics accompanied by an abrupt change in both electrical resistivity and optical infrared (IR transmittance was observed from the optimized sample. Remarkably, the transition temperature (TMIT deduced from the resistivity-temperature curve was reasonably consistent with that obtained from the temperature-dependent IR transmittance. Based on Raman measurement and XPS analyses, the observations were interpreted in terms of residual stresses and chemical stoichiometry. This achievement will be of great benefit for practical application of VO2-based smart windows.

  4. Ultrafast Dynamics of the VO2 Insulator-to-Metal Transition Observed by Nondegenerate Pump-Probe Spectroscopy

    Directory of Open Access Journals (Sweden)

    Haglund R. F.

    2013-03-01

    Full Text Available Non-degenerate pump (1.5 eV-probe (0.4 eV transmission spectroscopy on vanadium dioxide films grown on glass and three different sapphire substrates shows systematic variations with substrate that correlate with VO2 grain size and laser fluence. Temperature dependent measurements showed changes in the electronic response that is proportional to the metallic fraction.

  5. Carbon Quantum Dot Surface-Engineered VO2 Interwoven Nanowires: A Flexible Cathode Material for Lithium and Sodium Ion Batteries.

    Science.gov (United States)

    Balogun, Muhammad-Sadeeq; Luo, Yang; Lyu, Feiyi; Wang, Fuxin; Yang, Hao; Li, Haibo; Liang, Chaolun; Huang, Miao; Huang, Yongchao; Tong, Yexiang

    2016-04-20

    The use of electrode materials in their powdery form requires binders and conductive additives for the fabrication of the cells, which leads to unsatisfactory energy storage performance. Recently, a new strategy to design flexible, binder-, and additive-free three-dimensional electrodes with nanoscale surface engineering has been exploited in boosting the storage performance of electrode materials. In this paper, we design a new type of free-standing carbon quantum dot coated VO2 interwoven nanowires through a simple fabrication process and demonstrate its potential to be used as cathode material for lithium and sodium ion batteries. The versatile carbon quantum dots that are vastly flexible for surface engineering serve the function of protecting the nanowire surface and play an important role in the diffusion of electrons. Also, the three-dimensional carbon cloth coated with VO2 interwoven nanowires assisted in the diffusion of ions through the inner and the outer surface. With this unique architecture, the carbon quantum dot nanosurface engineered VO2 electrode exhibited capacities of 420 and 328 mAh g(-1) at current density rate of 0.3 C for lithium and sodium storage, respectively. This work serves as a milestone for the potential replacement of lithium ion batteries and next generation postbatteries.

  6. The effect of urinary cadmium on cardiovascular fitness as measured by VO2 max in white, black and Mexican Americans

    International Nuclear Information System (INIS)

    Egwuogu, Heartley; Shendell, Derek G.; Okosun, Ike S.; Goodfellow, Lynda

    2009-01-01

    Objectives: We explored potential effects of cadmium exposure on cardiovascular fitness measures, including gender and racial/ethnic differences. Methods: Data were from the 1999 to 2000 National Health and Nutrition Examination Survey (NHANES); 1963 participating subjects were included in our analysis. Volume of oxygen consumed at sub-maximum activity (VO 2 max) were recorded in a series of graded exercises; the goal was to elicit 75% of predetermined age-specific heart rates. Cadmium from urine samples was measured in the laboratory using standard methods. Multivariate linear regression analyses were performed to determine potential relationships. Results: Increased urinary cadmium concentrations were generally associated with decreased estimated VO 2 max values. Gender and racial/ethnic differences were also observed. Specifically, associations were statistically significant for white males and Mexican American females. Conclusion: Inverse associations between urinary cadmium concentrations and estimated VO 2 max values were observed, including racial and gender differences. The implications of such gender and racial/ethnic differences on long-term cardiovascular health and health disparities of present public health concern warrant further investigation

  7. Effect of Omega-3 PUFAs Supplementation with Lifestyle Modification on Anthropometric Indices and Vo2 max in Overweight Women.

    Science.gov (United States)

    Haghravan, Simin; Keshavarz, Seyed Ali; Mazaheri, Reza; Alizadeh, Zahra; Mansournia, Mohammad Ali

    2016-05-01

    Despite the fact that the recommendations of counteracting obesity advocate for changing lifestyle and physical activity habits, the prevalence of obesity continues to rise. The aim of the study was to investigate the effect of omega-3 PUFAs supplementation with lifestyle modification on anthropometric indices and Vo2max in overweight women. Fifty overweight women aged between 20 to 45 years were recruited in this interventional study. Women randomly were divided into two experimental groups (n = 25). Group 1 received omega-3 supplement, aerobic exercise program, and a healthy diet education. Group 2 was similar to group 1, except in that patients received placebo instead of omega-3 capsules. Experimental and placebo group subjects were asked to take one supplementary capsule every day, for 8 weeks. Anthropometric indices were measured in the fourth and eighth weeks of the trial. The maximum aerobic capacity (Vo2max) was determined using a gas analysis device. The level of significance for comparing the results before and after the trial was considered at P study (P modification has positive effects on anthropometric indices and Vo2max in overweight women.

  8. Mesoscopic structural phase progression in photo-excited VO2 revealed by time-resolved x-ray diffraction microscopy

    Science.gov (United States)

    Zhu, Yi; Cai, Zhonghou; Chen, Pice; Zhang, Qingteng; Highland, Matthew J.; Jung, Il Woong; Walko, Donald A.; Dufresne, Eric M.; Jeong, Jaewoo; Samant, Mahesh G.; Parkin, Stuart S. P.; Freeland, John W.; Evans, Paul G.; Wen, Haidan

    2016-02-01

    Dynamical phase separation during a solid-solid phase transition poses a challenge for understanding the fundamental processes in correlated materials. Critical information underlying a phase transition, such as localized phase competition, is difficult to reveal by measurements that are spatially averaged over many phase separated regions. The ability to simultaneously track the spatial and temporal evolution of such systems is essential to understanding mesoscopic processes during a phase transition. Using state-of-the-art time-resolved hard x-ray diffraction microscopy, we directly visualize the structural phase progression in a VO2 film upon photoexcitation. Following a homogenous in-plane optical excitation, the phase transformation is initiated at discrete sites and completed by the growth of one lattice structure into the other, instead of a simultaneous isotropic lattice symmetry change. The time-dependent x-ray diffraction spatial maps show that the in-plane phase progression in laser-superheated VO2 is via a displacive lattice transformation as a result of relaxation from an excited monoclinic phase into a rutile phase. The speed of the phase front progression is quantitatively measured, and is faster than the process driven by in-plane thermal diffusion but slower than the sound speed in VO2. The direct visualization of localized structural changes in the time domain opens a new avenue to study mesoscopic processes in driven systems.

  9. Van der Waals MoS2/VO2 heterostructure junction with tunable rectifier behavior and efficient photoresponse.

    Science.gov (United States)

    Oliva, Nicoló; Casu, Emanuele Andrea; Yan, Chen; Krammer, Anna; Rosca, Teodor; Magrez, Arnaud; Stolichnov, Igor; Schueler, Andreas; Martin, Olivier J F; Ionescu, Adrian Mihai

    2017-10-27

    Junctions between n-type semiconductors of different electron affinity show rectification if the junction is abrupt enough. With the advent of 2D materials, we are able to realize thin van der Waals (vdW) heterostructures based on a large diversity of materials. In parallel, strongly correlated functional oxides have emerged, having the ability to show reversible insulator-to-metal (IMT) phase transition by collapsing their electronic bandgap under a certain external stimulus. Here, we report for the first time the electronic and optoelectronic characterization of ultra-thin n-n heterojunctions fabricated using deterministic assembly of multilayer molybdenum disulphide (MoS 2 ) on a phase transition material, vanadium dioxide (VO 2 ). The vdW MoS 2 /VO 2 heterojunction combines the excellent blocking capability of an n-n junction with a high conductivity in on-state, and it can be turned into a Schottky rectifier at high applied voltage or at temperatures higher than 68 °C, exploiting the metal state of VO 2 . We report tunable diode-like current rectification with a good diode ideality factor of 1.75 and excellent conductance swing of 120 mV/dec. Finally, we demonstrate unique tunable photosensitivity and excellent junction photoresponse in the 500/650 nm wavelength range.

  10. Anti-biofouling function of amorphous nano-Ta2O5 coating for VO2-based intelligent windows

    Science.gov (United States)

    Li, Jinhua; Guo, Geyong; Wang, Jiaxing; Zhou, Huaijuan; Shen, Hao; Yeung, Kelvin W. K.

    2017-04-01

    From environmental and health perspectives, the acquisition of a surface anti-biofouling property holds important significance for the usability of VO2 intelligent windows. Herein, we firstly deposited amorphous Ta2O5 nanoparticles on VO2 film by the magnetron sputtering method. It was found that the amorphous nano-Ta2O5 coating possessed a favorable anti-biofouling capability against Pseudomonas aeruginosa as an environmental microorganism model, behind which lay the mechanism that the amorphous nano-Ta2O5 could interrupt the microbial membrane electron transport chain and significantly elevate the intracellular reactive oxygen species (ROS) level. A plausible relationship was established between the anti-biofouling activity and physicochemical nature of amorphous Ta2O5 nanoparticles from the perspective of defect chemistry. ROS-induced oxidative damage gave rise to microbial viability loss. In addition, the amorphous nano-Ta2O5 coating can endow VO2 with favorable cytocompatibility with human skin fibroblasts. This study may provide new insights into understanding the anti-biofouling and antimicrobial actions of amorphous transition metal oxide nanoparticles, which is conducive to expanding their potential applications in environmental fields.

  11. Views on peak oil and its relation to climate change policy

    International Nuclear Information System (INIS)

    Verbruggen, Aviel; Al Marchohi, Mohamed

    2010-01-01

    Definitions of fossil fuel reserves and resources and assessed stock data are reviewed and clarified. Semantics explain a large stake of conflict between advocate and critical voices on peak oil. From a holistic sources-sinks perspective, limited carrying capacity of atmospheric sinks, not absolute scarcity in oil resources, will impose tight constraints on oil use. Eventually observed peaks in oil production in nearby years will result from politically imposed limits on carbon emissions, and not be caused by physical lack of oil resources. Peak-oil belief induces passive climate policy attitudes when suggesting carbon dioxide emissions will peak naturally linked to dwindling oil supplies. Active policies for reducing emissions and use of fossil fuels will also encompass higher energy end-use prices. Revenues obtained from higher levies on oil use can support financing energy efficiency and renewable energy options. But when oil producers charge the higher prices they can pump new oil for many decades, postponing peak oil to occur while extending carbon lock-in.

  12. Flexible 3D Fe@VO2 core-shell mesh: A highly efficient and easy-recycling catalyst for the removal of organic dyes.

    Science.gov (United States)

    Li, Jing; Wang, Ruoqi; Su, Zhen; Zhang, Dandan; Li, Heping; Yan, Youwei

    2018-10-01

    Nowadays, it is extremely urgent to search for efficient and effective catalysts for water purification due to the severe worldwide water-contamination crises. Here, 3D Fe@VO 2 core-shell mesh, a highly efficient catalyst toward removal of organic dyes with excellent recycling ability in the dark is designed and developed for the first time. This novel core-shell structure is actually 304 stainless steel mesh coated by VO 2 , fabricated by an electrophoretic deposition method. In such a core-shell structure, Fe as the core allows much easier separation from the water, endowing the catalyst with a flexible property for easy recycling, while VO 2 as the shell is highly efficient in degradation of organic dyes with the addition of H 2 O 2 . More intriguingly, the 3D Fe@VO 2 core-shell mesh exhibits favorable performance across a wide pH range. The 3D Fe@VO 2 core-shell mesh can decompose organic dyes both in a light-free condition and under visible irradiation. The possible catalytic oxidation mechanism of Fe@VO 2 /H 2 O 2 system is also proposed in this work. Considering its facile fabrication, remarkable catalytic efficiency across a wide pH range, and easy recycling characteristic, the 3D Fe@VO 2 core-shell mesh is a newly developed high-performance catalyst for addressing the universal water crises. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. Preparation and Characterization of Epitaxial VO2 Films on Sapphire Using Postepitaxial Topotaxy Route via Epitaxial V2O3 Films

    Science.gov (United States)

    Yamaguchi, Iwao; Manabe, Takaaki; Tsuchiya, Tetsuo; Nakajima, Tomohiko; Sohma, Mitsugu; Kumagai, Toshiya

    2008-02-01

    Epitaxial VO2 films were prepared on the C-planes of α-Al2O3 substrates by a metal organic deposition (MOD) process. It was difficult to obtain the single phase of (010)M-oriented VO2 films, in which the subscript M refers to the monoclinic indices, by the heat treatment of amorphous precursor films in the VO2-stable region after the pyrolysis of the coating solution. The product films consisted of discontinuous circular grains of 1-2 µm size on the substrate surface. Therefore, we prepared the (010)M-oriented epitaxial VO2 films using postepitaxial topotaxy (PET), that is, topotactic oxidation of (0001)-oriented epitaxial V2O3 films. First, epitaxial V2O3(0001) films were obtained by MOD starting with a vanadium naphthenate solution. Second, the epitaxial V2O3(0001) films were topotactically oxidized at 500 °C in an Ar-O2 gas mixture with pO2 = 10-4 atm to obtain (010)M-oriented epitaxial VO2 films. The epitaxial relationships were VO2(010)M ∥ α-Al2O3(0001) and VO2[100]M ∥ α-Al2O3[0110], [1010], [1100]. The VO2(010)M films exhibited metal-semiconductor transitions with hysteresis loops at 60-80 °C. The resistivity change before and after the transition of the VO2(010)M film oxidized for 6 h was three orders of magnitude.

  14. Comparison of structured and unstructured physical activity training on predicted VO2max and heart rate variability in adolescents - a randomized control trial.

    Science.gov (United States)

    Sharma, Vivek Kumar; Subramanian, Senthil Kumar; Radhakrishnan, Krishnakumar; Rajendran, Rajathi; Ravindran, Balasubramanian Sulur; Arunachalam, Vinayathan

    2017-05-01

    Physical inactivity contributes to many health issues. The WHO-recommended physical activity for adolescents encompasses aerobic, resistance, and bone strengthening exercises aimed at achieving health-related physical fitness. Heart rate variability (HRV) and maximal aerobic capacity (VO2max) are considered as noninvasive measures of cardiovascular health. The objective of this study is to compare the effect of structured and unstructured physical training on maximal aerobic capacity and HRV among adolescents. We designed a single blinded, parallel, randomized active-controlled trial (Registration No. CTRI/2013/08/003897) to compare the physiological effects of 6 months of globally recommended structured physical activity (SPA), with that of unstructured physical activity (USPA) in healthy school-going adolescents. We recruited 439 healthy student volunteers (boys: 250, girls: 189) in the age group of 12-17 years. Randomization across the groups was done using age and gender stratified randomization method, and the participants were divided into two groups: SPA (n=219, boys: 117, girls: 102) and USPA (n=220, boys: 119, girls: 101). Depending on their training status and gender the participants in both SPA and USPA groups were further subdivided into the following four sub-groups: SPA athlete boys (n=22) and girls (n=17), SPA nonathlete boys (n=95) and girls (n=85), USPA athlete boys (n=23) and girls (n=17), and USPA nonathlete boys (n=96) and girls (n=84). We recorded HRV, body fat%, and VO2 max using Rockport Walk Fitness test before and after the intervention. Maximum aerobic capacity and heart rate variability increased significantly while heart rate, systolic blood pressure, diastolic blood pressure, and body fat percentage decreased significantly after both SPA and USPA intervention. However, the improvement was more in SPA as compared to USPA. SPA is more beneficial for improving cardiorespiratory fitness, HRV, and reducing body fat percentage in terms of

  15. X-ray absorption spectroscopy of single-crystalline (VO)2P2O7: Electronic structure and possible exchange paths

    International Nuclear Information System (INIS)

    Gerhold, S.; Nu''cker, N.; Kuntscher, C. A.; Schuppler, S.; Stadler, S.; Idzerda, Y. U.; Prokofiev, A. V.; Bu''llesfeld, F.; Assmus, W.

    2001-01-01

    Using polarization-dependent V2p and O1s near-edge x-ray absorption spectroscopy, we studied the unoccupied electronic structure of single-crystalline (VO) 2 P 2 O 7 . It is highly anisotropic, and shows similarities to vanadium oxides like VO 2 and V 2 O 5 at the V2p edge and at the O1s threshold. The contributions from V-O and P-O orbitals could be identified. The results rule out the spin ladder model for the magnetic behavior of (VO) 2 P 2 O 7 , but are consistent with the alternating chain scenario

  16. Relative thermoluminescent efficiencies proton/gamma and helium/gamma of peaks of high temperature in TLD-100 dosemeters

    International Nuclear Information System (INIS)

    Flores M, E.

    2007-01-01

    The increase of the applications of ion beams in radiotherapy treatments has generated interest in the study of the thermoluminescent materials (TL) that allow to determine the applied doses. A way to quantify the TL response from these materials to ions is by means of the relative thermoluminescent efficiency. In the group of Thermoluminescent dosimetry of the Institute of Physics of the UNAM (IFUNAM) the thermoluminescent response of the TLD-100 dosemeters has been studied, which present a glow curve characteristic with several peaks that correspond to traps and luminescent centers in the material. The stable peaks know each other as 4, 5, 6a, 6b, 7, 8, 9 and 10. The efficiencies should be measured using the response so much to the radiation of interest (in this case protons and helium ions) as the response to gamma radiation. In previous works with ions of low energy taken place in the Pelletron accelerator of the IFUNAM was only measured the TL efficiency for the peak 5 and the total signal. It had not been possible to measure the efficiency of the peaks of high temperature (6a-10) because, for the gamma radiation, the peaks of high temperature show very small signals; however, recently Massillon carries out measures of efficiency TL of peaks of high temperature for ions of intermediate energy using a protocol special of reading and of deconvolution that allows to measure the signals coming from the peaks of high temperature. In this work is implemented this same protocol to complete the study of TL efficiencies at low energy of protons and helium and to determine if the values of efficiency depend on the used reading protocol. For it is reported it measures of the relative efficiency of the peaks of high temperature from the TLD-100 exposed to protons of 1.5 MeV and nuclei of helium of 3 and 7.5 MeV. (Author)

  17. Peak Velocity as an Alternative Method for Training Prescription in Mice.

    Science.gov (United States)

    Picoli, Caroline de Carvalho; Romero, Paulo Vitor da Silva; Gilio, Gustavo R; Guariglia, Débora A; Tófolo, Laize P; de Moraes, Solange M F; Machado, Fabiana A; Peres, Sidney B

    2018-01-01

    Purpose: To compare the efficiency of an aerobic physical training program prescribed according to either velocity associated with maximum oxygen uptake (vVO 2max ) or peak running speed obtained during an incremental treadmill test (V peak_K ) in mice. Methods: Twenty male Swiss mice, 60 days old, were randomly divided into two groups with 10 animals each: 1. group trained by vVO 2max (GVO 2 ), 2. group trained by V peak_K (GVP). After the adaptation training period, an incremental test was performed at the beginning of each week to adjust training load and to determine the amount of VO 2 and VCO 2 fluxes consumed, energy expenditure (EE) and run distance during the incremental test. Mice were submitted to 4 weeks of aerobic exercise training of moderate intensity (velocity referring to 70% of vVO 2max and V peak_K ) in a programmable treadmill. The sessions lasted from 30 to 40 min in the first week, to reach 60 min in the fourth week, in order to provide the mice with a moderate intensity exercise, totaling 20 training sessions. Results: Mice demonstrated increases in VO 2max (ml·kg -1 ·min -1 ) (GVO 2 = 49.1% and GVP = 56.2%), V peak_K (cm·s -1 ) (GVO 2 = 50.9% and GVP = 22.3%), EE (ml·kg -0,75 ·min -1 ) (GVO 2 = 39.9% and GVP = 51.5%), and run distance (cm) (GVO 2 = 43.5% and GVP = 33.4%), after 4 weeks of aerobic training (time effect, P < 0.05); there were no differences between the groups. Conclusions: V peak_K , as well as vVO 2max , can be adopted as an alternative test to determine the performance and correct prescription of systemized aerobic protocol training to mice.

  18. Facile and Low-Temperature Fabrication of Thermochromic Cr2O3/VO2 Smart Coatings: Enhanced Solar Modulation Ability, High Luminous Transmittance and UV-Shielding Function.

    Science.gov (United States)

    Chang, Tianci; Cao, Xun; Li, Ning; Long, Shiwei; Gao, Xiang; Dedon, Liv R; Sun, Guangyao; Luo, Hongjie; Jin, Ping

    2017-08-09

    In the pursuit of energy efficient materials, vanadium dioxide (VO 2 ) based smart coatings have gained much attention in recent years. For smart window applications, VO 2 thin films should be fabricated at low temperature to reduce the cost in commercial fabrication and solve compatibility problems. Meanwhile, thermochromic performance with high luminous transmittance and solar modulation ability, as well as effective UV shielding function has become the most important developing strategy for ideal smart windows. In this work, facile Cr 2 O 3 /VO 2 bilayer coatings on quartz glasses were designed and fabricated by magnetron sputtering at low temperatures ranging from 250 to 350 °C as compared with typical high growth temperatures (>450 °C). The bottom Cr 2 O 3 layer not only provides a structural template for the growth of VO 2 (R), but also serves as an antireflection layer for improving the luminous transmittance. It was found that the deposition of Cr 2 O 3 layer resulted in a dramatic enhancement of the solar modulation ability (56.4%) and improvement of luminous transmittance (26.4%) when compared to single-layer VO 2 coating. According to optical measurements, the Cr 2 O 3 /VO 2 bilayer structure exhibits excellent optical performances with an enhanced solar modulation ability (ΔT sol = 12.2%) and a high luminous transmittance (T lum,lt = 46.0%), which makes a good balance between ΔT sol and T lum for smart windows applications. As for UV-shielding properties, more than 95.8% UV radiation (250-400 nm) can be blocked out by the Cr 2 O 3 /VO 2 structure. In addition, the visualized energy-efficient effect was modeled by heating a beaker of water using infrared imaging method with/without a Cr 2 O 3 /VO 2 coating glass.

  19. Use of ZnO as antireflective, protective, antibacterial, and biocompatible multifunction nanolayer of thermochromic VO2 nanofilm for intelligent windows

    International Nuclear Information System (INIS)

    Zhou, Huaijuan; Li, Jinhua; Bao, Shanhu; Li, Jian; Liu, Xuanyong; Jin, Ping

    2016-01-01

    Graphical abstract: - Highlights: • A multifunctional VO 2 /ZnO bilayer film is designed and deposited by magnetron sputtering apparatus. • The ZnO top layer can enhance the antireflective, antioxidative and anti-corrosion functions of the VO 2 film. • The ZnO top layer can endow VO 2 film with excellent antibacterial performance. • The ZnO top layer can attenuate the cytotoxicity of VO 2 thin film. - Abstract: A multifunctional VO 2 /ZnO bilayer film is designed and deposited by magnetron sputtering apparatus. The integration of the antireflective, antioxidative and anti-corrosion functions, and antibacterial performance makes the heterostructure film a promising candidate in the energy-saving smart window. The ZnO thin film as the antireflection layer can markedly boost the solar regulation efficiency (ΔT sol ) from 7.7% to 12.2% and possesses excellent luminous transmittance (T lum-L = 50.3%) in the low-temperature semiconductor phase. The ZnO layer as the protection barrier can not only protect VO 2 thin film from oxidation to much toxic V 2 O 5 , but also decrease the release of V ions. Besides, the synergistic effect of releasing killing by Zn 2+ ions and contact killing by ZnO NPs makes ZnO thin film an outstanding antibacterial coating. In terms of the biological safety, ZnO coating with appropriate film thickness can effectively attenuate the cytotoxicity of VO 2 on human HIBEpiC cells. We hope this work can provide new insights for better designing of novel multifunctional VO 2 -based intelligent energy-saving windows.

  20. Effects of exercise and group counselling on body composition and VO2max in overweight women with polycystic ovary syndrome.

    Science.gov (United States)

    Roessler, Kirsten K; Birkebaek, Camilla; Ravn, Pernille; Andersen, Marianne S; Glintborg, Dorte

    2013-03-01

    Polycystic ovary syndrome (PCOS) is often associated with an increased waist circumference and with lower cardio-respiratory fitness as a consequence of obesity, which may be improved by physical activity. To investigate the effect of high-intensity aerobic training combined with group counselling sessions on anthropometry and cardio-respiratory fitness in women with PCOS. Seventeen sedentary, overweight women with PCOS were randomized in a cross-over design to 16 weeks of intervention: eight weeks high-intensity aerobic exercise was followed by eight weeks of group counselling (n = 8) or vice versa (n = 9). Fourteen of the women completed the tests. Waist circumference, body mass index and maximal aerobic capacity (VO(2max) ) were measured at baseline, cross-over and post-intervention. There was a decrease in waist circumference (119.9 vs. 106.5 cm) and body mass index (34.9 vs. 34.4 kg/m(2) ) and an increase in VO(2max) (2554.9 vs. 2807.9 mL/min) during the intervention period (t = 16 weeks, n = 14), all p group which started with group counselling (2.9 vs. 0.6 kg, t = 16 weeks, n = 14, p = 0.055). Exercise in groups followed by counselling or vice versa had beneficial effects on waist circumference, weight, and VO(2max) in women with PCOS. Future studies should examine possible beneficial effects of combined group counselling and exercise on weight loss and adherence to exercise protocols among women with PCOS. © 2013 The Authors Acta Obstetricia et Gynecologica Scandinavica © 2013 Nordic Federation of Societies of Obstetrics and Gynecology.

  1. Augmentation of thermoelectric performance of VO2 thin films irradiated by 200 MeV Ag9+-ions

    International Nuclear Information System (INIS)

    Khan, G.R.; Kandasami, A.; Bhat, B.A.

    2016-01-01

    Swift Heavy Ion (SHI) irradiation with 200 MeV Ag 9+ -ion beam at ion fluences of 1E11, 5E11, 1E12, and 5E12 for tuning of electrical transport properties of VO 2 thin films fabricated by so–gel technique on alumina substrates has been demonstrated in the present paper. The point defects created by SHI irradiation modulate metal to insulator phase transition temperature, carrier concentration, carrier mobility, electrical conductivity, and Seebeck coefficient of VO 2 thin films. The structural properties of the films were characterized by XRD and Raman spectroscopy and crystallite size was found to decrease upon irradiation. The atomic force microscopy revealed that the surface roughness of specimens first decreased and then increased with increasing fluence. Both resistance as well as Seebeck coefficient measurements demonstrated that all the samples exhibit metal–insulator phase transition and the transition temperatures decreases with increasing fluence. Hall effect measurements exhibited that carrier concentration increased continuously with increasing fluence which resulted in an increase of electrical conductivity by several orders of magnitude in the insulating phase. Seebeck coefficient in insulating phase remained almost constant in spite of an increase in the electrical conductivity by several orders of magnitude making SHI irradiation an alternative stratagem for augmentation of thermoelectric performance of the materials. The carrier mobility at room temperature decreased up to the beam fluence of 5E11 and then started increasing whereas Seebeck coefficient in metallic state first increased with increasing ion beam fluence up to 5E11 and thereafter decreased. Variation of these electrical transport parameters has been explained in detail. - Highlights: • Thermoelectric properties of VO 2 thin films enhance upon SHI irradiation. • Structural properties show that crystallite size decrease upon SHI irradiation. • Metal–insulator phase

  2. Effects of exercise and group counselling on body composition and VO(2max) in overweight women with polycystic ovary syndrome

    DEFF Research Database (Denmark)

    Roessler, Kirsten Kaya; Birkebaek, Camilla; Ravn, Pernille

    2013-01-01

    with group counselling sessions on anthropometry and cardio-respiratory fitness in women with PCOS. DESIGN: Seventeen sedentary, overweight women with PCOS were randomized in a cross-over design to 16 weeks of intervention: Eight weeks high intensity aerobic exercise was followed by eight weeks group...... counselling (n=8) or vice versa (n=9). Fourteen of the women completed the tests. MAIN OUTCOME MEASURES: Waist circumference, body mass index and maximal aerobic capacity (VO(2max) ) were measured at baseline, cross-over and post-intervention. RESULTS: Waist circumference (119.9 vs. 106.5 cm) and body mass...

  3. Desenvolvimento de equações para estimativa do VO2PICO pelo teste de 9 minutos

    Directory of Open Access Journals (Sweden)

    Ana Carolina Paludo

    2014-06-01

    Full Text Available OBJETIVO: Desenvolver e validar modelos matemáticos para predição do VO2pico em crianças e adolescentes, por meio da utilização do teste de campo de corrida/caminhada de 9 minutos. MÉTODOS: Foram avaliados 211 escolares, de sete a 12 anos de idade, de ambos os sexos, regularmente matriculados em duas escolas do Município de Londrina - PR, sendo 141 escolares separados para amostra de desenvolvimento e 70 para validação das equações desenvolvidas. As medidas avaliadas foram: massa corporal, estatura, espessuras de dobras cutâneas (tricipital e subescapular, além da maturação biológica. Os testes de corrida/caminha de 9 minutos foram realizados em pista de atletismo e a análise direta do VO2pico (mL/kg/min realizada em laboratório, com analisador de gás portátil, através um teste incremental em esteira rolante. O desenvolvimento das equações foi realizado através da análise de regressão linear pelo método stepwise e a validação foi realizada pelos testes matemáticos específicos levando em consideração uma significância de 5% para todas as análises. RESULTADOS: A equação geral para a amostra total foi VO2pico= 24,506+16,672 (maturação, 0=pré e 1=púbere e pós - 0,346 (Σ DC + 5,187 (sexo, 0=F e 1=M + 0,009 (distância com um r=0,742 e EPE=9,149 mL/kg/min e sua validação apresentou r=0,570, CCI= 0,68, limites de concordância de -1,4 mL/kg/min, EPE=8,39 mL/kg/min e CV= 21,94%. CONCLUSÃO: Conclui-se que a equação generalizada desenvolvida fornece uma estimativa válida do VO2pico em crianças e adolescentes de sete a 12 anos de idade.

  4. Nonlinear interaction of infrared waves on a VO2 surface at a semiconductor-metal phase transition

    Science.gov (United States)

    Berger, N. K.; Zhukov, E. A.; Novokhatskii, V. V.

    1984-04-01

    Nonlinear interactions (including wavefront reversal) of light from CW or pulsed 10.6-micron CO2 lasers at the semiconductor-metal phase transition in a VO2 film are investigated experimentally. The results are presented in graphs and characterized in detail. The intensity reflection coefficients of the three-wave interactions are found to be 0.5 percent for a CW reference wave of intensity 900 mW/sq cm and 42 percent for a pulsed reference wave of threshold density 600-800 microjoule/sq cm.

  5. Hydrogen related peaks in Cu-LaNi4.7Al0.3

    International Nuclear Information System (INIS)

    Cuscueta, D.J.; Salva, H.R.; Ghilarducci, A.A.; Ruiz, F.C.

    2009-01-01

    In this work, the effect of Ni substitution by Cu in the LaNi 4.7 Al 0.3 hydride-forming alloy was studied in order to apply it to the negative electrodes of Ni-MH batteries. SEM, EDS and X-ray diffraction techniques were used to analyze the microstructure, composition and crystalline structure of the samples. A maximum electrochemical discharge capacity of 130 mAh/g was obtained. Internal friction (IF) and shear modulus (G) were measured by means of low frequency mechanical spectroscopy, between 100 and 450 K. In the electrochemical activated sample, two main IF peaks and typical relaxation steps in G showed up at 200 and 280 K. The first is ascribed to interactions between hydrides and H atoms in solid solution and dislocations, while the last one is attributed to the β ↔ α hydride phase transformation.

  6. A acurácia da determinação do VO2max e do limiar anaeróbio La exactitud en la determinacion del VO2máx y del umbral anaerobico Accuracy of VO2max and anaerobic threshold determination

    Directory of Open Access Journals (Sweden)

    Paulo Cesar N Granja Filho

    2005-06-01

    Full Text Available São raros estudos que tratam da acurácia de parâmetros de trocas gasosas durante o esforço, com a população brasileira. OBJETIVO: Determinar a confiabilidade do consumo máximo de oxigênio (VO2max e do limiar anaeróbio (LAn, assim como, a objetividade do segundo (LAn em adultos jovens saudáveis. MÉTODOS: Foram aplicados dois testes de esforço máximo, a partir dos quais dois observadores independentes determinaram o LAn através do método de inspeção visual. Os dados foram tratados por meio da análise de regressão, coeficiente de correlação intraclasse (CCI, ANOVA com dois fatores com teste post hoc de Tukey e teste t pareado para alfa Son raros los estudios que tratan de la exactitud de los parámetros de cambios gaseosos durante el esfuerzo con la población brasileña. OBJETIVO: Determinar la confiabilidad del consumo máximo de oxigeno (VO2max y del umbral anaeróbico (LAn, así como la objetividad del segundo, (LAn en adultos jovenes saludables. MÉTODOS: Fueron aplicados dos tests de esfuerzo máximo, a partir de los cuales dos observadores independientes determinaron el LAn a través del método de inspección visual. Los datos fueron tratados por medio del análisis de regresión, coeficiente de relación intraclase (CCI, ANOVA com dos factores con test post hoc de Tukey y el test t apareado para alfa Studies on the accuracy of the gas exchange and ventilation parameters during exertion involving the Brazilian population are scarce in literature. OBEJCTIVE: To determine the reliability of the maximal oxygen intake (VO2max and anaerobic threshold (AnT, as well as the objectivity of the AnT determination in Brazilian healthy youth adults. METHODS: Two tests of maximal exertion were applied. Two independent observers applied the visual inspection method for the AnT determination. The data were compared by means of the regression analysis, intraclass correlation coefficient (ICC, two-way ANOVA and the paired t-test for an

  7. Resolving the chicken-and-egg problem in VO2: a new paradigm for the Mott transition

    Science.gov (United States)

    Najera, Oscar; Civelli, Marcello; Dobrosavljevi, Vladimir; Rozenberg, Marcelo

    We consider a minimal model to investigate the metal-insulator transition in VO2. We adopt a Hubbard model with two orbital per unit cell, which captures the competition between Mott and singlet-dimer localization. We solve the model within Dynamical Mean Field Theory, characterizing in detail the metal-insulator transition and finding new features in the electronic states. We compare our results with available experimental data obtaining good agreement in the relevant model parameter range. Crucially, we can account for puzzling optical conductivity data obtained within the hysteresis region, which we associate to a novel metallic state characterized by a split heavy quasiparticle band. Our results show that the thermal-driven insulator-to-metal transition in VO2 is entirely compatible with a Mott electronic mechanism, solving a long standing ''chicken-and-egg'' debate and calling for further research of ``Mottronics'' applications of this system. This work was partially supported by public Grants from the French National Research Agency (ANR), project LACUNES No ANR-13-BS04-0006-01, the NSF DMR-1005751 and DMR-1410132.

  8. Formation of different micro-morphologies from VO2 and ZnO crystallization using macro-porous silicon substrates

    Science.gov (United States)

    Salazar-Kuri, U.; Antúnez, E. E.; Estevez, J. O.; Olive-Méndez, Sion F.; Silva-González, N. R.; Agarwal, V.

    2017-05-01

    Square-shaped macropores produced by electrochemical anodization of n- and p-type Si wafers have been used as centers of nucleation to crystallize VO2 and ZnO. Substrate roughness dependent formation of different morphologies is revealed in the form of squared particles, spheres, bars and ribbons in the case of VO2 and hexagonal piles and spheres in the case of ZnO, have been observed.The presence of nano-/micro-metric crystals was studied through field emission scanning electron microscopy and energy dispersive X-ray spectroscopy mapping. Crystal structure of metal oxides was confirmed by micro-Raman spectroscopy. The growth of the different morphologies has been explained in terms of the surface free energy of a bare Si/SiO2 substrate and its modification originated from the roughness of the surface and of the walls of the porous substrates. This energy plays a crucial role on the minimization of the required energy to induce heterogeneous nucleation and crystal growth. Present work strengthens and provides an experimental evidence of roughness dependent metal oxide crystal growth with well-defined habits from pore corners and rough sides of the pore walls, similar to already reported protein crystals.

  9. Relative thermoluminescent efficiencies proton/gamma and helium/gamma of high temperature peaks in TLD-100 dosemeters

    International Nuclear Information System (INIS)

    Flores M, E.; Avila, O.; Rodriguez V, M.; Massillon, J.L.G.; Buenfil A, E.; Ruiz T, C.; Brandan, M.E.; Gamboa De Buen, I.

    2007-01-01

    This work presents measures of relative thermoluminescent efficiency of those high temperature peaks of TLD-100 dosemeters exposed to protons of 1.5 MeV and to helium nuclei of 3 and 7.5 MeV. A rigorous reading and of deconvolution protocol was used for the calculation of the TL efficiencies. Additionally an Excel program that facilitated the deconvolution adjustment process of the glow curves was elaborated. (Author)

  10. 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...

  11. PELATIHAN LARI SIRKUIT 2 X 10 MENIT DAN PELATIHAN LARI KONTINYU 2 X 10 MENIT DAPAT MENINGKATKAN VO2 MAX TAEKWONDOIN PUTRA KABUPATEN MANGGARAI - NTT

    Directory of Open Access Journals (Sweden)

    Regina Sesilia Noy

    2014-08-01

    Full Text Available VO2 max is very important in everyday life, so as to facilitate any physicalactivity, specially for athletes in order to achieve maximum performance. In aneffort to increase VO2 max training should be carried out regularly, measured andplanned. This study aims to determine the increase in VO2 max through circuittraining run and run continuously. The sample is taekwondoin son Manggarai-NTTwith an average age of 15 years. This study is an experimental study with the studydesign used was Randomized Pre and Post Test Group desigen. With a totalsample of 7 people in each group. Samples were randomly selected. Treatmentgroup 1 (KP1 given training run circuit 2 x 10 minute and Treatment Group 2(KP2 are given continuous training run 2 x 10 minute. Training carried out for 6weeks with a frequency of four times a week starting at 17:00 to 18:00 pm locatedat Frans Sales Lega Airport Manggarai-NTT. The analysis showed an increase inVO2 max was significantly (p <0.05 against both groups fled. In both groups thecircuit run by Pulse Oxymeter and Norma Cooper an increase in VO2 max with p<0.05, as well as a continuous run either by Pulse Oxymeter and Norma Cooperwith an increase in VO2 max value of p <0.05. The results of this analysis meansthat either the training or circuit training run run continuously to improve VO2max. Based on a comparison of test data by an independent test after training inboth groups either by Pulse Oxymeter and Norma Cooper in get p values > 0.05, orthere is no significant difference. Based on these results it can be concluded thatthe run circuit training and continuous training run together can increase VO2 maxand there was no significant difference. The results of this study are expected toincrease the knowledge of coaches, teachers and taekwondoin to perform trainingon a regular basis and are also expected to do similar research that examines VO2max with different training.

  12. Metal-semiconductor transition materials. FeS and VO2 thin films by RF reactive sputtering

    International Nuclear Information System (INIS)

    Fu, Ganhua

    2007-06-01

    In the present work, two MST systems, FeS and VO 2 thin films were investigated. Iron sulfide thin films over a range of composition were prepared by reactive sputtering. The influence of the substrate, sputter power, substrate temperature and stoichiometry on the structure and MST of iron sulfide films was investigated. Iron sulfide films deposited at different temperatures show temperature dependent structure and MST. FeS films on float glass show (110) and (112) orientations when the substrate temperature is 200 and 500 C, respectively. The transition temperature and width of the hysteresis loop determined from the temperature dependent conductivity curves of iron sulfide films decrease with the substrate temperature. Fe and S excess in FeS films both result in the decrease of the transition temperature and width of the hysteresis loop. The vacuum-annealing affects the MST of FeS films significantly. When FeS films were annealed below the deposition temperature, the transition temperature decreases; otherwise increases. The residual stress plays an important role during the annealing process. The higher the residual stress inside the FeS films is, the higher the transition temperature of FeS films. With the increase of the annealing temperature, the residual stress in FeS films is first released and then enhances, which gives rise first to the decrease and then increase of the transition temperature of FeS films. At high substrate temperatures, the residual stress is higher. In addition, the MST of FeS films was influenced by the ambient aging. With the increase of the aging time, the transition temperature first increases and then decreases. FeS films with different thicknesses were prepared. The correlation between the film thickness (grain size) and the MST switching characteristics of FeS films was established. With the decrease of the grain size, the density of grain boundaries increases, causing the increase of the conductivity of the semiconducting phase

  13. Fabrication and electrical resistivity of Mo-doped VO2 thin films coated on graphite conductive plates by a sol-gel method

    Energy Technology Data Exchange (ETDEWEB)

    Choi, W.; Jung, H.M.; Um, S. [Hanyang Univ., Seoul (Korea, Republic of). School of Mechanical Engineering

    2008-07-01

    Vanadium oxides (VO2) can be used in optical devices, thermochromic smart windows and sensors. This paper reported on a study in which vanadium pentoxide (V2O5) powder was prepared and mixed with Molybdenum Oxides (MoO3) to form Mo-doped and -undoped VO2 thin films by a sol-gel method on graphite conductive substrates. The micro-structure and chemical compositions of the Mo-doped and -undoped VO2 thin films was investigated using X-Ray diffraction and scanning electron microscopy. Changes in electrical resistivity were measured as a function of the stoichiometric compositions between vanadium and molybdenum. In this study. Mo-doped and -undoped VO2 thin films showed the typical metal to insulator transition (MIT), where temperature range could be adjusted by modifying the dopant atomic ratio. The through-plane substrate structure of the Mo-doped layer influences the electrical resistivity of the graphite substrate. As the amount of the molybdenum increases, the electrical resistivity of the graphite conductive substrate decreases in the lower temperature range below the freezing point of water. The experimental results showed that if carefully controlled, thermal dissipation of VO2 thin films can be used as a self-heating source to melt frozen water with the electrical current flowing through the graphite substrate. 3 refs., 3 figs.

  14. Two-Dimensional SiO2/VO2 Photonic Crystals with Statically Visible and Dynamically Infrared Modulated for Smart Window Deployment.

    Science.gov (United States)

    Ke, Yujie; Balin, Igal; Wang, Ning; Lu, Qi; Tok, Alfred Iing Yoong; White, Timothy J; Magdassi, Shlomo; Abdulhalim, Ibrahim; Long, Yi

    2016-12-07

    Two-dimensional (2D) photonic structures, widely used for generating photonic band gaps (PBG) in a variety of materials, are for the first time integrated with the temperature-dependent phase change of vanadium dioxide (VO 2 ). VO 2 possesses thermochromic properties, whose potential remains unrealized due to an undesirable yellow-brown color. Here, a SiO 2 /VO 2 core/shell 2D photonic crystal is demonstrated to exhibit static visible light tunability and dynamic near-infrared (NIR) modulation. Three-dimensional (3D) finite difference time domain (FDTD) simulations predict that the transmittance can be tuned across the visible spectrum, while maintaining good solar regulation efficiency (ΔT sol = 11.0%) and high solar transmittance (T lum = 49.6%). Experiments show that the color changes of VO 2 films are accompanied by NIR modulation. This work presents a novel way to manipulate VO 2 photonic structures to modulate light transmission as a function of wavelength at different temperatures.

  15. Relation between peak period of microtremor spectral ratio (horizontal and vertical components) and basement depth; Bido no suiheido/jogedo supekutoru hi no peak to kiso shindo tono kankei

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, H; Mizutani, K; Saito, T [Iwate University, Iwate (Japan). Faculty of Engineering

    1996-05-01

    The peak period of the horizontal/vertical spectral ratio of microtremors was referred to the underground structure for the purpose of finding out if it was possible to estimate the ground structure by use of the peak period of the spectral ratio. The observation was carried in the areas of Morioka City and Hachinohe City using seismographs for measuring east-west, north-south, and up-down motions. As for the relationship between the peak period of the spectral ratio distribution involving 490 observation sites and the known gravity anomalies in the Morioka City area, it was found that the peak period of the spectral ratio tended to be shorter from west toward east while the gravity anomalies were greater from west toward east. Again, as for the relations with the underground geology, the period was longer when the distance to the granite basement was greater, and shorter when smaller. In the Hachinohe City area, relations not only of the first period peak but also of the second period peak to the basement were disclosed, which indicates the possibility that the peak period of the spectral ratio will be used as a means for estimating the basement structure. 2 refs., 8 figs.

  16. Letrozole, an aromatase inhibitor, reduces post-peak age-related regression of rooster reproductive performance.

    Science.gov (United States)

    Ali, Emad Abdulgabbar; Zhandi, Mahdi; Towhidi, Armin; Zaghari, Mojtaba; Ansari, Mahdi; Najafi, Mojtaba; Deldar, Hamid

    2017-08-01

    This study was designed to evaluate orally administrated Letrozole (Lz) on reproductive performance, plasma testosterone and estradiol concentrations and relative abundance of mRNA of GnRH, FSH and LH in roosters. Ross 308 roosters (n=32) that were 40-weeks of age were individually housed and received a basal standard diet supplemented different amounts of capsulated Lz [0 (Lz-0), 0.5 (Lz-0.5), 1 (Lz-1) or 1.5 (Lz-1.5), mg Lz/bird/day] for 12 weeks. Sperm quality variables and plasma testosterone and estradiol concentrations were assessed from the first to the tenth week of the treatment period. Semen samples from the 11th to 12th week were used for artificial insemination and eggs were collected and allotted to assess fertility and hatchability rates. Relative abundance of hypothalamic and pituitary GnRH, LH and FSH mRNA was evaluated at the end of 12th week. The results indicated that total and forward sperm motility as well as egg hatchability rate were greater in the Lz-0.5 group. Greater sperm concentrations, ejaculate volume, sperm plasma membrane integrity, testis index and fertility rates were recorded for both Lz-0.5 and Lz-1 groups compared with the Lz-0 group (Proosters. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Pemberian minuman kombinasi maltodekstrin dan vitamin C terhadap mood negatif dan VO2 maks atlet sepak bola

    Directory of Open Access Journals (Sweden)

    Yuni Afriani

    2017-04-01

    Full Text Available Background: Stress during the match can influence the change of mood and performance of athletes. Physical exercise can improve the ability of physiologically and psychologically, but lead to fatigue, dehydration and hypoglycemia. Maltodextrin has a lower osmolarity to improve emotional and performance. Vitamin C as a cofactor of neurotransmitters can support the performance of athletes. Objective: This study aimed to determine the effectiveness of a combination drinks of maltodextrin and vitamin C on mood and the correlation with VO2 max of football athletes. Method: This research is a quasi experimental with same subject design. The subjects were 14 University state of Yogyakarta football athlete. Subjects received a drink of 15% maltodextrin and 250 mg of vitamin C in 300 ml given 30 minutes before and 5 minutes after the performance test using yo-yo intermittent test continued by physical exercise. Measurement of mood would be done in 3 times; before cardiorespiratory test, 5 minutes after physical exercise, and 15 minutes after drink. Results: There are significant changes after consuming a combination of maltodextrin and vitamin C on the confusion (p0.05. There are significant changes after consuming plain water on fatigue and tension (p0.05. There are no significant differences in every components of mood between two treatments. There is a correlation between anger and confusion with cardiorespiratory after consuming a combination of maltodextrin and vitamin C. Conclusion: Maltodextrin and vitamin C has the potential effect to improve the mood condition and have a correlation with VO2 Max improvement in football athletes.

  18. Room Temperature Optical Constants and Band Gap Evolution of Phase Pure M1-VO2 Thin Films Deposited at Different Oxygen Partial Pressures by Reactive Magnetron Sputtering

    Directory of Open Access Journals (Sweden)

    Meng Jiang

    2014-01-01

    Full Text Available Spectroscopic ellipsometry study was employed for phase pure VO2(M1 thin films grown at different oxygen partial pressures by reactive magnetron sputtering. The optical constants of the VO2(M1 thin films have been determined in a photon energy range between 0.73 and 5.05 eV. The near-infrared extinction coefficient and optical conductivity of VO2(M1 thin films rapidly increase with decreasing O2-Ar ratios. Moreover, two electronic transitions can be uniquely assigned. The energy gaps correlated with absorption edge (E1 at varied O2-Ar ratios are almost the same (~2.0 eV; consequently, the absorption edge is not significantly changed. However, the optical band gap corresponding to semiconductor-to-metal phase transition (E2 decreases from 0.53 to 0.18 eV with decreasing O2-Ar ratios.

  19. Høyintensiv aerob intervalltrening utført som ekstrembolk fører ikke til endringer i VO2max hos elitesyklister og ??riatleter

    OpenAIRE

    Pedersen, Frank-Gøran

    2014-01-01

    HENSIKT: Studien hadde til hensikt å undersøke virkningen av høyintensiv aerob intervalltrening (HAIT) på maksimalt oksygenopptak (VO2max) og tid på Time trial (TT) hos elitesyklister og triatleter. METODE: 11 forsøkspersoner, n=7 HAIT (31±9) og n=4 kontroll (27±11), VO2max HAIT 62.6±6.4, VO2max 65.6±5.7 gjennomførte denne studien. HAIT gjennomførte 14 intervalløkter (4x4 løpeintervaller på tredemølle, 3-5%stigning, 90-95% av Hfmax, 3 minutter aktiv hvile på ca. 70% av Hfmax) over ti dager,et...

  20. New intelligent multifunctional SiO2/VO2 composite films with enhanced infrared light regulation performance, solar modulation capability, and superhydrophobicity.

    Science.gov (United States)

    Wang, Chao; Zhao, Li; Liang, Zihui; Dong, Binghai; Wan, Li; Wang, Shimin

    2017-01-01

    Highly transparent, energy-saving, and superhydrophobic nanostructured SiO 2 /VO 2 composite films have been fabricated using a sol-gel method. These composite films are composed of an underlying infrared (IR)-regulating VO 2 layer and a top protective layer that consists of SiO 2 nanoparticles. Experimental results showed that the composite structure could enhance the IR light regulation performance, solar modulation capability, and hydrophobicity of the pristine VO 2 layer. The transmittance of the composite films in visible region ( T lum ) was higher than 60%, which was sufficient to meet the requirements of glass lighting. Compared with pristine VO 2 films and tungsten-doped VO 2 film, the near IR control capability of the composite films was enhanced by 13.9% and 22.1%, respectively, whereas their solar modulation capability was enhanced by 10.9% and 22.9%, respectively. The water contact angles of the SiO 2 /VO 2 composite films were over 150°, indicating superhydrophobicity. The transparent superhydrophobic surface exhibited a high stability toward illumination as all the films retained their initial superhydrophobicity even after exposure to 365 nm light with an intensity of 160 mW . cm -2 for 10 h. In addition, the films possessed anti-oxidation and anti-acid properties. These characteristics are highly advantageous for intelligent windows or solar cell applications, given that they can provide surfaces with anti-fogging, rainproofing, and self-cleaning effects. Our technique offers a simple and low-cost solution to the development of stable and visible light transparent superhydrophobic surfaces for industrial applications.

  1. Synthesis of sub-10 nm VO2 nanoparticles films with plasma-treated glass slides by aqueous sol–gel method

    International Nuclear Information System (INIS)

    Lan, Shi-Di; Cheng, Chih-Chia; Huang, Chi-Hsien; Chen, Jem-Kun

    2015-01-01

    Highlights: • Sub-10 nm VO 2 nanoparticles (VNPs) are synthesized on a plasma-treated glass. • Glass slides generate negative charges sites after plasma treatment to attract VO 2 + . • Doping tungsten with 1 wt% in VNPs did not change particle size significantly. • The particle size of VNP can be tuned by the density of negative charge sites. • Sub-10 nm structured VO 2 particle films exhibited high visible transmittance. - Abstract: This paper describes an aqueous sol–gel synthesis of thermochromic thin films consisted of vanadium dioxide nanoparticles (VNPs) on glass slides. The glass slides were treated by argon/oxygen plasma to generate dispersedly negative charge sites on the surface to attract VO 2 + from a sol–gel solution. After heat treatment in a low-pressure carbon monoxide/carbon dioxide (CO/CO 2 ) atmosphere, the VNPs could be generated in sub-10 nm of particle size on the surface. Various levels of doping were achieved by adding small quantities of a water-soluble tungsten compound to the sol; however, the particle size increased slightly with the tungsten doping levels. The change in electrical conductivity with temperature for VNP films were measured and compared to VO 2 crystalline films. VNP films exhibited the lower transition temperature of the semiconductor to metal phase change; at a doping level of 4 wt% the transition temperature was measured at 32.2 ± 1.2 and 24.1 ± 1.2 °C for the VO 2 and VNP films, respectively. The VNP films showed excellent visible transparency and a large change in transmittance at near-infrared (NIR) wavelengths before and after the metal–insulator phase transition (MIT). The current method is a landmark in the development of nanostructured material toward applications in energy-saving smart windows.

  2. Physical and performance-related profile of elite male South African ...

    African Journals Online (AJOL)

    VO2max) evaluations were performed on male (n=23) distance athletes. The means and standard deviations of the parameters are as follows: Percentage fat 8.0% (±1.3), percentage muscle 46.2% (±2.9), VO2max 70.1ml/kg/min (±5.2), peak ...

  3. Predição da potência aeróbia (VO2máx de crianças e adolescentes em teste incremental na esteira rolante Prediction of aerobic power (VO2max of children and adolescents during an incremental treadmill test

    Directory of Open Access Journals (Sweden)

    Fabiana Andrade Machado

    2013-03-01

    Full Text Available O consumo máximo de oxigênio (VO2máx é a quantidade máxima de energia que pode ser produzida pelo metabolismo aeróbio em determinada unidade de tempo, podendo ser determinado direta ou indiretamente através de equações preditivas. O objetivo deste trabalho foi elaborar uma equação preditiva específica para determinar o VO2máx de meninos de 10 a 16 anos. Quarenta e dois meninos realizaram teste ergoespirométrico de corrida em esteira rolante com velocidade inicial de 9 km/h até exaustão voluntária. Através da regressão linear múltipla foi possível desenvolver a seguinte equação para a determinação indireta do VO2máx: VO2máx (ml/min = -1574,06 + (141,38 x Vpico + (48,34 * Massa corporal, com erro padrão de estimativa = 191,5 ml/min (4,10 ml/kg/min e o coeficiente de determinação = 0,934. Sugerimos que esta é uma fórmula adequada para predizer o VO2máx para esta população.The maximal oxygen uptake (VO2max is the maximal quantity of energy that can be produced by the aerobic metabolism in certain time unity. It can be determined direct or indirectly by predictive equations. The objective of this study was to make a specific predictive equation to determine the VO2max from boys aged 10-16 years-old. Forty-two boys underwent a treadmill running ergospirometric test, with the initial velocity set at 9 km/h, until voluntary exhaustion. By the multiple linear regression was possible to develop the following equation for the indirect determination of the VO2max: VO2max (ml/min = -1574.06 + (141.38 x Vpeak + (48.34 * Body mass, with standard error of estimate = 191.5 ml/min (4.10 ml/kg/min and coefficient of determination = 0.934. We suggest that this formula is appropriate to predict VO2max for this population.

  4. Estimativa das contribuições dos sistemas anaeróbio lático e alático durante exercícios de cargas constantes em intensidades abaixo do VO2max Estimation of contributions of the anaerobic lactic and alactic systems during constant-load exercises at intensities below the VO2max

    Directory of Open Access Journals (Sweden)

    Marcos David Silva-Cavalcante

    2013-01-01

    Full Text Available O objetivo do estudo foi estimar as contribuições do metabolismo anaeróbio lático (MAL e alático (MAA em intensidades abaixo do consumo máximo de oxigênio (VO2max. Dez homens (23 ± 4 anos, 176,4 ± 6,8 cm, 72,4 ± 8,2 kg, 12,0 ± 4,5 % de gordura corporal realizaram um teste progressivo até a exaustão voluntária para identificação do VO2max, da potência correspondente ao VO2max (WVO2max e do segundo limiar ventilatório (LV2. Na segunda e na terceira visita foram realizados seis testes de cargas constantes (três testes por sessão com intensidades abaixo do VO2max. Houve uma predominância do MAL sobre o MAA durante os exercícios submáximos a partir da intensidade correspondente ao LV2, sendo significativamente maior em 90% VO2max (p The purpose this study was that estimated contributions of the anaerobic lactic (MAL and alactic (MAA metabolism during constant load exercises at intensities below the maximal oxygen capacity uptake (VO2max. Ten males (23 ± 4 years, 176.4 ± 6.8 cm, 72.4 ± 8.2 kg, 12.0 ± 4.5 % of fat body performed in the first visit a progressive test until exhaustion to identification of VO2max, power output corresponding to the VO2max (WVO2max and second ventilatory threshold (LV2. On the second and third visit, the participants performed six constant workload tests (3 per session with intensities below VO2max. There was a predominance of MAL about MAA during the exercises sub-maximal from intensity corresponding to the LV2, being significantly higher at 90% VO2max (p < 0.05. Thus, these results may help coaches to implement training loads appropriate to their athletes, according to the metabolic demand of the competition.

  5. Safety Evaluation Report related to the operation of Comanche Peak Steam Electric Station, Unit 2 (Docket No. 50-446)

    International Nuclear Information System (INIS)

    1993-02-01

    Supplement 26 to the Safety Evaluation Report related to the operation of the Comanche Peak Steam Electric Station (CPSES), Unit 2, has been prepared by the Office of Nuclear Reactor Regulation of the US Nuclear Regulatory Commission (NRC). The facility is located in Somervell County, Texas, approximately 40 miles southwest of Fort Worth, Texas. This supplement reports the status of certain issues that had not been resolved when the Safety Evaluation Report and Supplements 1, 2, 3, 4, 6, 12, 21, 22, 23, 24, and 25 to that report were published. This supplement deals primarily with Unit 2 issues; however, it also references evaluations for several licensing issues that relate to Unit 1, which have been resolved since Supplement 25 was issued

  6. Associations between VO2max and vitality in older workers: A cross-sectional study

    NARCIS (Netherlands)

    Strijk, J.E.; Proper, K.I.; Klaver, L.; Beek, A.J. van der; Mechelen, W. van

    2010-01-01

    Background. To prevent early exit from work, it is important to study which factors contribute to healthy ageing. One concept that is assumed to be closely related to, and therefore may influence healthy ageing, is vitality. Vitality consists of both a mental and a physical component, and is

  7. Decoupling the Lattice Distortion and Charge Doping Effects on the Phase Transition Behavior of VO2 by Titanium (Ti4+) Doping

    Science.gov (United States)

    Wu, Yanfei; Fan, Lele; Liu, Qinghua; Chen, Shi; Huang, Weifeng; Chen, Feihu; Liao, Guangming; Zou, Chongwen; Wu, Ziyu

    2015-01-01

    The mechanism for regulating the critical temperature (TC) of metal-insulator transition (MIT) in ions-doped VO2 systems is still a matter of debate, in particular, the unclear roles of lattice distortion and charge doping effects. To rule out the charge doping effect on the regulation of TC, we investigated Ti4+-doped VO2 (TixV1-xO2) system. It was observed that the TC of TixV1-xO2 samples first slightly decreased and then increased with increasing Ti concentration. X-ray absorption fine structure (XAFS) spectroscopy was used to explore the electronic states and local lattice structures around both Ti and V atoms in TixV1-xO2 samples. Our results revealed the local structure evolution from the initial anatase to the rutile-like structure around the Ti dopants. Furthermore, the host monoclinic VO2 lattice, specifically, the VO6 octahedra would be subtly distorted by Ti doping. The distortion of VO6 octahedra and the variation of TC showed almost the similar trend, confirming the direct effect of local structural perturbations on the phase transition behavior. By comparing other ion-doping systems, we point out that the charge doping is more effective than the lattice distortion in modulating the MIT behavior of VO2 materials. PMID:25950809

  8. Intracellular [Ca2+] and Vo2 after manipulation of the free-energy of the Na+/Ca(2+)-exchanger in isolated rat ventricular myocytes

    NARCIS (Netherlands)

    Fiolet, J. W.; Baartscheer, A.; Schumacher, C. A.

    1995-01-01

    We have investigated whether the Na+/Ca(2+)-exchanger has a functional regulatory role in the control of oxidative metabolism in suspensions of isolated rat ventricular myocytes. Therefore we simultaneously measured intracellular [Ca2+] ([Ca2+]i) with Indo-1 and respiratory rate (Vo2) after abrupt

  9. The role of haemoglobin mass on VO(2)max following normobaric 'live high-train low' in endurance-trained athletes

    DEFF Research Database (Denmark)

    Robach, Paul; Siebenmann, Christoph; Jacobs, Robert A

    2012-01-01

    It remains unclear by which mechanism 'live high-train low' (LHTL) altitude training increases exercise performance. Haematological and skeletal muscle adaptations have both been proposed. To test the hypotheses that (i) LHTL improves maximal oxygen uptake (VO(2)max) and (ii) this improvement is ...

  10. Room-temperature subnanosecond waveguide lasers in Nd:YVO4 Q-switched by phase-change VO2: A comparison with 2D materials.

    Science.gov (United States)

    Nie, Weijie; Li, Rang; Cheng, Chen; Chen, Yanxue; Lu, Qingming; Romero, Carolina; Vázquez de Aldana, Javier R; Hao, Xiaotao; Chen, Feng

    2017-04-06

    We report on room-temperature subnanosecond waveguide laser operation at 1064 nm in a Nd:YVO 4 crystal waveguide through Q-switching of phase-change nanomaterial vanadium dioxide (VO 2 ). The unique feature of VO 2 nanomaterial from the insulating to metallic phases offers low-saturation-intensity nonlinear absorptions of light for subnanosecond pulse generation. The low-loss waveguide is fabricated by using the femtosecond laser writing with depressed cladding geometry. Under optical pump at 808 nm, efficient pulsed laser has been achieved in the Nd:YVO 4 waveguide, reaching minimum pulse duration of 690 ps and maximum output average power of 66.7 mW. To compare the Q-switched laser performances by VO 2 saturable absorber with those based on two-dimensional materials, the 1064-nm laser pulses have been realized in the same waveguide platform with either graphene or transition metal dichalcogenide (in this work, WS 2 ) coated mirror. The results on 2D material Q-switched waveguide lasers have shown that the shortest pulses are with 22-ns duration, whilst the maximum output average powers reach ~161.9 mW. This work shows the obvious difference on the lasing properties based on phase-change material and 2D materials, and suggests potential applications of VO 2 as low-cost saturable absorber for subnanosecond laser generation.

  11. Growth of VO2 Nano wires from Supercooled Liquid Nano droplets and E-beam Irradiation for Ultra-sensitive sensor

    International Nuclear Information System (INIS)

    Byun, Ji Won; Baik, Jeong Min; Lee, Sang Hyun; Lee, Byung Cheol

    2011-01-01

    Vanadium dioxide is an interesting material on account of its easily accessible and sharp Mott metal-insulator transition at ∼ 68 .deg. C in the bulk, which is of great interest in sensing and catalytic applications. In this Paper, we describe the synthesis and properties of VO 2 nano wires as novel catalytic and gas sensor materials based on electron beam irradiation. High yields of single crystalline VO 2 nano wires are synthesized by atmospheric-pressure, physical vapor deposition using V 2 O 5 layer. Pd-decorated VO 2 nano wire sensors show extraordinary sensitivity towards hydrogen, an almost 3 order-of-magnitude increase in the current through the nano wire. By the Eb irradiation, the conductance of the nano wires significantly increased up to 5 times, reducing the response time by half and the operating temperature. The metal nanoparticles-VO 2 nano wire system will be very promising for high-sensitivity and high-selectivity under low temperature less than 100. deg. C

  12. Raman spectroscopy of WO3 nano-wires and thermo-chromism study of VO2 belts produced by ultrasonic spray and laser pyrolysis techniques

    CSIR Research Space (South Africa)

    Mwakikunga, BW

    2008-01-01

    Full Text Available . This was carried out us- ing MathmatcaTM. Electrical resistances of the VO2 (R) nanobelts (NBs) were measured at different points on the sample using a digital multi-meter and heated base coupled with a tem- perature controller. The Varian Cary 500...

  13. Preexercise metabolic alkalosis induced via bicarbonate ingestion accelerates Vo2 kinetics at the onset of a high-power-output exercise in humans.

    Science.gov (United States)

    Zoladz, Jerzy A; Szkutnik, Zbigniew; Duda, Krzysztof; Majerczak, Joanna; Korzeniewski, Bernard

    2005-03-01

    The present study investigated the effect of preexercise metabolic alkalosis on the primary component of oxygen uptake (Vo(2)) kinetics, characterized by tau(1). Seven healthy physically active nonsmoking men, aged 22.4 +/- 1.8 (mean +/- SD) yr, maximum Vo(2) (Vo(2 max)) 50.4 +/- 4 ml.min(-1).kg(-1), performed two bouts of cycling, corresponding to 40 and 87% of Vo(2 max), lasting 6 min each, separated by a 20-min pause, once as a control study and a few days later at approximately 90 min after ingestion of 3 mmol/kg body wt of NaHCO(3). Blood samples for measurements of bicarbonate concentration and hydrogen ion concentration were taken from antecubital vein via catheter. Pulmonary Vo(2) was measured continuously breath by breath. The values of tau(1) were calculated by using six various approaches published in the literature. Preexercise level of bicarbonate concentration after ingestion of NaHCO(3) was significantly elevated (P < 0.01) compared with the control study (28.96 +/- 2.11 vs. 24.84 +/- 1.18 mmol/l; P < 0.01), and [H(+)] was significantly (P < 0.01) reduced (42.79 +/- 3.38 nmol/l vs. 46.44 +/- 3.51 nmol/l). This shift (P < 0.01) was also present during both bouts of exercise. During cycling at 40% of Vo(2 max), no significant effect of the preexercise alkalosis on the magnitude of tau(1) was found. However, during cycling at 87% of Vo(2 max), the tau(1) calculated by all six approaches was significantly (P < 0.05) reduced, compared with the control study. The tau(1) calculated as in Borrani et al. (Borrani F, Candau R, Millet GY, Perrey S, Fuchsloscher J, and Rouillon JD. J Appl Physiol 90: 2212-2220, 2001) was reduced on average by 7.9 +/- 2.6 s, which was significantly different from zero with both the Student's t-test (P = 0.011) and the Wilcoxon's signed-ranks test (P = 0.014).

  14. Inclusão do equivalente energético do lactato na regressão VO2-intensidade em corrida horizontal e inclinada (10,5%

    Directory of Open Access Journals (Sweden)

    Victor Machado REIS

    Full Text Available Resumo O estudo teve por objetivo analisar o efeito da adição do equivalente energético do lactato sanguíneo com a medida de VO2 durante a corrida em esteira horizontal (0% e inclinada (10,5%, como forma de estimativa do custo energético da corrida. Treze corredores de meia e longa distância (idade 28,1 ± 4,2 anos; estatura 1,75 ± 0,07 m; massa corporal 65,2 ± 4,9 kg; VO2max 70,3 ± 4,9 ml·kg-1·min-1 cumpriram dois testes em esteira rolante (0% e 10,5% que incluíram vários estágios em intensidade constante. Foram calculadas para cada atleta as regressões VO2-velocidade, bem como regressões alternativas com a adição de um equivalente energético de 3 ml O2 Eq·kg-1·mM [La-] às medições de VO2. Não se verificou interação significativa entre a adição do equivalente do lactato e a inclinação da esteira. A ANOVA indicou um efeito significativo da adição do equivalente do lactato na inclinação da reta de regressão e na estimativa do custo energético. Os tamanhos do efeito obtidos indicam que este efeito é mais forte na corrida horizontal. Estes resultados sugerem que em testes laboratoriais com corredores treinados se deverá considerar a adição dos valores de VO2 com os equivalentes energéticos do lactato.

  15. Atomic Origins of Monoclinic-Tetragonal (Rutile) Phase Transition in Doped VO 2 Nanowires

    KAUST Repository

    Asayesh-Ardakani, Hasti

    2015-10-12

    There has been long-standing interest in tuning the metal-insulator phase transition in vanadium dioxide (VO) via the addition of chemical dopants. However, the underlying mechanisms by which doping elements regulate the phase transition in VO are poorly understood. Taking advantage of aberration-corrected scanning transmission electron microscopy, we reveal the atomistic origins by which tungsten (W) dopants influence the phase transition in single crystalline WVO nanowires. Our atomically resolved strain maps clearly show the localized strain normal to the (122¯) lattice planes of the low W-doped monoclinic structure (insulator). These strain maps demonstrate how anisotropic localized stress created by dopants in the monoclinic structure accelerates the phase transition and lead to relaxation of structure in tetragonal form. In contrast, the strain distribution in the high W-doped VO structure is relatively uniform as a result of transition to tetragonal (metallic) phase. The directional strain gradients are furthermore corroborated by density functional theory calculations that show the energetic consequences of distortions to the local structure. These findings pave the roadmap for lattice-stress engineering of the MIT behavior in strongly correlated materials for specific applications such as ultrafast electronic switches and electro-optical sensors.

  16. Atomic Origins of Monoclinic-Tetragonal (Rutile) Phase Transition in Doped VO 2 Nanowires

    KAUST Repository

    Asayesh-Ardakani, Hasti; Nie, Anmin; Marley, Peter M.; Zhu, Yihan; Phillips, Patrick J.; Singh, Sujay; Mashayek, Farzad; Sambandamurthy, Ganapathy; Low, Ke Bin; Klie, Robert F.; Banerjee, Sarbajit; Odegard, Gregory M.; Shahbazian-Yassar, Reza

    2015-01-01

    There has been long-standing interest in tuning the metal-insulator phase transition in vanadium dioxide (VO) via the addition of chemical dopants. However, the underlying mechanisms by which doping elements regulate the phase transition in VO are poorly understood. Taking advantage of aberration-corrected scanning transmission electron microscopy, we reveal the atomistic origins by which tungsten (W) dopants influence the phase transition in single crystalline WVO nanowires. Our atomically resolved strain maps clearly show the localized strain normal to the (122¯) lattice planes of the low W-doped monoclinic structure (insulator). These strain maps demonstrate how anisotropic localized stress created by dopants in the monoclinic structure accelerates the phase transition and lead to relaxation of structure in tetragonal form. In contrast, the strain distribution in the high W-doped VO structure is relatively uniform as a result of transition to tetragonal (metallic) phase. The directional strain gradients are furthermore corroborated by density functional theory calculations that show the energetic consequences of distortions to the local structure. These findings pave the roadmap for lattice-stress engineering of the MIT behavior in strongly correlated materials for specific applications such as ultrafast electronic switches and electro-optical sensors.

  17. Safety Evaluation Report related to the operation of Comanche Peak Steam Electric Station, Unit 2 (Docket No. 50-446)

    International Nuclear Information System (INIS)

    1992-09-01

    This document supplement 25 to the Safety Evaluation Report related to the operation of the Comanche Peak Steam Electric Station (CPSES), Unit 2 (NUREG-0797), has been prepared by the Office of Nuclear Reactor Regulation of the US Nuclear Regulatory Commission (NRC). The facility is located in Somervell County, Texas, approximately 40 miles southwest of Fort Worth, Texas. This supplement reports the status of certain issues that had not been resolved when the Safety Evaluation Report and Supplements 1, 2, 3, 4, 6, 12, 21, 22, 23, and 24 to that report were published. This supplement deals primarily with Unit 2 issues; however, it also references evaluations for several Unit 1 licensing items resolved since Supplement 24 was issued

  18. Peak Velocity as an Alternative Method for Training Prescription in Mice

    Directory of Open Access Journals (Sweden)

    Caroline de Carvalho Picoli

    2018-02-01

    Full Text Available Purpose: To compare the efficiency of an aerobic physical training program prescribed according to either velocity associated with maximum oxygen uptake (vVO2max or peak running speed obtained during an incremental treadmill test (Vpeak_K in mice.Methods: Twenty male Swiss mice, 60 days old, were randomly divided into two groups with 10 animals each: 1. group trained by vVO2max (GVO2, 2. group trained by Vpeak_K (GVP. After the adaptation training period, an incremental test was performed at the beginning of each week to adjust training load and to determine the amount of VO2 and VCO2 fluxes consumed, energy expenditure (EE and run distance during the incremental test. Mice were submitted to 4 weeks of aerobic exercise training of moderate intensity (velocity referring to 70% of vVO2max and Vpeak_K in a programmable treadmill. The sessions lasted from 30 to 40 min in the first week, to reach 60 min in the fourth week, in order to provide the mice with a moderate intensity exercise, totaling 20 training sessions.Results: Mice demonstrated increases in VO2max (ml·kg−1·min−1 (GVO2 = 49.1% and GVP = 56.2%, Vpeak_K (cm·s−1 (GVO2 = 50.9% and GVP = 22.3%, EE (ml·kg−0,75·min−1 (GVO2 = 39.9% and GVP = 51.5%, and run distance (cm (GVO2 = 43.5% and GVP = 33.4%, after 4 weeks of aerobic training (time effect, P < 0.05; there were no differences between the groups.Conclusions: Vpeak_K, as well as vVO2max, can be adopted as an alternative test to determine the performance and correct prescription of systemized aerobic protocol training to mice.

  19. Mean Velocity vs. Mean Propulsive Velocity vs. Peak Velocity: Which Variable Determines Bench Press Relative Load With Higher Reliability?

    Science.gov (United States)

    García-Ramos, Amador; Pestaña-Melero, Francisco L; Pérez-Castilla, Alejandro; Rojas, Francisco J; Gregory Haff, G

    2018-05-01

    García-Ramos, A, Pestaña-Melero, FL, Pérez-Castilla, A, Rojas, FJ, and Haff, GG. Mean velocity vs. mean propulsive velocity vs. peak velocity: which variable determines bench press relative load with higher reliability? J Strength Cond Res 32(5): 1273-1279, 2018-This study aimed to compare between 3 velocity variables (mean velocity [MV], mean propulsive velocity [MPV], and peak velocity [PV]): (a) the linearity of the load-velocity relationship, (b) the accuracy of general regression equations to predict relative load (%1RM), and (c) the between-session reliability of the velocity attained at each percentage of the 1-repetition maximum (%1RM). The full load-velocity relationship of 30 men was evaluated by means of linear regression models in the concentric-only and eccentric-concentric bench press throw (BPT) variants performed with a Smith machine. The 2 sessions of each BPT variant were performed within the same week separated by 48-72 hours. The main findings were as follows: (a) the MV showed the strongest linearity of the load-velocity relationship (median r = 0.989 for concentric-only BPT and 0.993 for eccentric-concentric BPT), followed by MPV (median r = 0.983 for concentric-only BPT and 0.980 for eccentric-concentric BPT), and finally PV (median r = 0.974 for concentric-only BPT and 0.969 for eccentric-concentric BPT); (b) the accuracy of the general regression equations to predict relative load (%1RM) from movement velocity was higher for MV (SEE = 3.80-4.76%1RM) than for MPV (SEE = 4.91-5.56%1RM) and PV (SEE = 5.36-5.77%1RM); and (c) the PV showed the lowest within-subjects coefficient of variation (3.50%-3.87%), followed by MV (4.05%-4.93%), and finally MPV (5.11%-6.03%). Taken together, these results suggest that the MV could be the most appropriate variable for monitoring the relative load (%1RM) in the BPT exercise performed in a Smith machine.

  20. Relation of Angina Pectoris to Outcomes, Quality of Life and Response to Exercise Training in Patients with Chronic Heart Failure (from HF-ACTION)

    Science.gov (United States)

    Parikh, Kishan S.; Coles, Adrian; Schulte, Phillip J.; Kraus, William E.; Fleg, Jerome L.; Keteyian, Steven J.; Piña, Ileana L.; Fiuzat, Mona; Whellan, David J.; O’Connor, Christopher M.; Mentz, Robert J.

    2016-01-01

    Angina pectoris (AP) is associated with worse outcomes in heart failure (HF). We investigated the association of AP with health-related quality of life (HRQoL), exercise capacity, and clinical outcomes, and its interaction with exercise training in a HF population. We grouped 2,331 HF patients with reduced ejection fraction (EF) in the HF-ACTION trial of usual care +/− exercise training according to whether they had self-reported AP by Canadian classification score (CCS). HRQoL and clinical outcomes were assessed by AP status. In HF-ACTION, 406 (17%) patients had AP at baseline (44% with CCS ≥ II) with HF severity similar to those without AP. Patients with AP had similar baseline exercise capacity but worse depressive symptoms and HRQoL. AP was associated with 22% greater adjusted risk for all-cause mortality/hospitalizations, driven by hospitalizations. There was significant interaction between baseline AP and exercise training peak VO2 change (P=0.019), but not other endpoints. Exercise training was associated with greater peak VO2 improvement after 3 months in patients with AP (treatment effect=1.25 mL/kg/min, 95% CI=0.6–1.9). In conclusion, AP was associated with worse HRQoL and depressive symptoms. Despite greater peak VO2 improvement with exercise training, patients with AP experienced more adverse outcomes. PMID:27561194

  1. For progress in natural science: Materials international investigations of structural phase transformation and THz properties across metal–insulator transition in VO2/Al2O3 epitaxial films

    Directory of Open Access Journals (Sweden)

    Mengmeng Yang

    2015-10-01

    Full Text Available Vanadium dioxide (VO2 epitaxial thin films on (0001-oriented Al2O3 substrates were prepared using radio frequency (RF magnetron sputtering techniques. To study the metal-insulator-transition (MIT mechanism and extend the applications of VO2 epitaxial films at terahertz (THz band, temperature-dependent X-ray diffraction (XRD and THz time domain spectroscopy of the VO2 epitaxial films were performed. Both the lattice constants and THz transmission exhibited a similar and sharp transition that was similar to that observed for the electrical resistance. Consequently, the MIT of the VO2/Al2O3 epitaxial films should be co-triggered by the structural phase transition and electronic transition. Moreover, the very large resistance change (on the order of ~103 and THz response (with a transmission modulation ratio of ~87% in the VO2/Al2O3 epitaxial heterostructures are promising for electrical switch and electro-optical device applications.

  2. Myosin heavy chain composition in the vastus lateralis muscle in relation to oxygen uptake and heart rate during cycling in humans.

    Science.gov (United States)

    Majerczak, J; Nieckarz, Z; Karasinski, J; Zoladz, J A

    2014-04-01

    In this study we examined the relationship between fast myosin heavy chain (MyHC2) content in the vastus lateralis and the rate of oxygen uptake (VO2) and heart rate (HR) increase during an incremental exercise in 38, young, healthy men. Prior to the exercise test, muscle biopsies were taken in order to evaluate the MyHC composition. It was found that during cycling performed below the lactate threshold (LT), a positive relationship between MyHC2 and the intercept of the oxygen uptake and power output (VO2-PO) relationship existed (r=0.49, P=0.002), despite no correlation between MyHC2 and the slope value of the VO2-PO relationship (r= -0.18, P=0.29). During cycling performed above the LT, MyHC2 correlated positively with the magnitude of the nonlinearity in the VO2-PO relationship; i.e. with the accumulated VO2'excess' (r=0.44, P=0.006) and peak VO2'excess' (r=0.44, P=0.006), as well as with the slope of the HR-PO relationship (r=0.49, P=0.002). We have concluded that a greater MyHC2 content in the vastus lateralis is accompanied by a higher oxygen cost of cycling during exercise performed below the LT. This seems to be related to the higher energy cost of the non-cross-bridge activities in the muscles possessing a greater proportion of MyHC2 content. In the case of heavy-intensity exercise, a higher MyHC2 content in the vastus lateralis is accompanied by greater non-linearity in the VO2-PO relationship, as well as a steeper increase in HR in the function of an increase of PO. This relationship can be explained by greater disturbances in metabolic stability in type II muscle fibres during exercise, resulting in a decrease of muscle mechanical efficiency and greater increase of heart rate at a given power output. Therefore, MyHC composition has an impact on the oxygen cost of cycling both below and above the LT.

  3. Skeletal muscle-specific expression of PGC-1α-b, an exercise-responsive isoform, increases exercise capacity and peak oxygen uptake.

    Directory of Open Access Journals (Sweden)

    Miki Tadaishi

    Full Text Available Maximal oxygen uptake (VO(2max predicts mortality and is associated with endurance performance. Trained subjects have a high VO(2max due to a high cardiac output and high metabolic capacity of skeletal muscles. Peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α, a nuclear receptor coactivator, promotes mitochondrial biogenesis, a fiber-type switch to oxidative fibers, and angiogenesis in skeletal muscle. Because exercise training increases PGC-1α in skeletal muscle, PGC-1α-mediated changes may contribute to the improvement of exercise capacity and VO(2max. There are three isoforms of PGC-1α mRNA. PGC-1α-b protein, whose amino terminus is different from PGC-1α-a protein, is a predominant PGC-1α isoform in response to exercise. We investigated whether alterations of skeletal muscle metabolism by overexpression of PGC-1α-b in skeletal muscle, but not heart, would increase VO(2max and exercise capacity.Transgenic mice showed overexpression of PGC-1α-b protein in skeletal muscle but not in heart. Overexpression of PGC-1α-b promoted mitochondrial biogenesis 4-fold, increased the expression of fatty acid transporters, enhanced angiogenesis in skeletal muscle 1.4 to 2.7-fold, and promoted exercise capacity (expressed by maximum speed by 35% and peak oxygen uptake by 20%. Across a broad range of either the absolute exercise intensity, or the same relative exercise intensities, lipid oxidation was always higher in the transgenic mice than wild-type littermates, suggesting that lipid is the predominant fuel source for exercise in the transgenic mice. However, muscle glycogen usage during exercise was absent in the transgenic mice.Increased mitochondrial biogenesis, capillaries, and fatty acid transporters in skeletal muscles may contribute to improved exercise capacity via an increase in fatty acid utilization. Increases in PGC-1α-b protein or function might be a useful strategy for sedentary subjects to perform exercise

  4. 'Peak oil' or 'peak demand'?

    International Nuclear Information System (INIS)

    Chevallier, Bruno; Moncomble, Jean-Eudes; Sigonney, Pierre; Vially, Rolland; Bosseboeuf, Didier; Chateau, Bertrand

    2012-01-01

    This article reports a workshop which addressed several energy issues like the objectives and constraints of energy mix scenarios, the differences between the approaches in different countries, the cost of new technologies implemented for this purposes, how these technologies will be developed and marketed, which will be the environmental and societal acceptability of these technical choices. Different aspects and issues have been more precisely presented and discussed: the peak oil, development of shale gases and their cost (will non conventional hydrocarbons modify the peak oil and be socially accepted?), energy efficiency (its benefits, its reality in France and other countries, its position in front of the challenge of energy transition), and strategies in the transport sector (challenges for mobility, evolution towards a model of sustainable mobility)

  5. Consumo máximo de oxígeno (vo2max en bomberos: revisión sistemática de estudios

    Directory of Open Access Journals (Sweden)

    Jimmy Rojas Quirós

    2013-07-01

    Full Text Available Consumo máximo de oxígeno (VO2max en bomberos: revisión sistemática de estudios. El trabajo de bombero es catalogada como una profesión de riesgo, con alto requerimiento físico; en los últimos años el bombero ha adquirido más competencias que la propia de apagar incendios, entre ellas las intervenciones en accidentes de tránsito, incidentes con materiales peligrosos, rescates, fuegos forestales, entre otros. La imagen del bombero tradicional ha dado paso a nuevos profesionales preparados para afrontar todo tipo de desastres por lo que se habla en la actualidad del bombero completo. El objetivo de este estudio fue revisar sistemáticamente la evidencia científica sobre los valores de consumo máximo de oxígeno (VO2max que presentan los bomberos. Se incluyeron un total de 19 estudios, publicados entre los años 2002 y 2012, de las bases de datos de EBSCOhost, SpringerLink, SPORTDiscus, Medline, Embase y Scielo; además de revistas como Journal of Sports Science & Medicine, Occupational Medicine y Psicothema. Se concluye con esta revisión, con base a los resultados de los estudios, que las diferentes poblaciones de bomberos, oscilan un VO2max de 39,20 a 58,21 ml/kg/min, que varía según la condición inicial que tienen los bomberos en los diferentes estudios que proponen los autores; en general se determina que un bombero debe poseer valores de VO2max por encima de los 43 ml/kg/min, lo cual es lo mínimo recomendable para al menos poseer una buena capacidad aeróbica que le permita desenvolverse en sus funciones básicas como bombero.

  6. Ambiguous Role of Growth-Induced Defects on the Semiconductor-to-Metal Characteristics in Epitaxial VO2/TiO2 Thin Films.

    Science.gov (United States)

    Mihailescu, Cristian N; Symeou, Elli; Svoukis, Efthymios; Negrea, Raluca F; Ghica, Corneliu; Teodorescu, Valentin; Tanase, Liviu C; Negrila, Catalin; Giapintzakis, John

    2018-04-25

    Controlling the semiconductor-to-metal transition temperature in epitaxial VO 2 thin films remains an unresolved question both at the fundamental as well as the application level. Within the scope of this work, the effects of growth temperature on the structure, chemical composition, interface coherency and electrical characteristics of rutile VO 2 epitaxial thin films grown on TiO 2 substrates are investigated. It is hereby deduced that the transition temperature is lower than the bulk value of 340 K. However, it is found to approach this value as a function of increased growth temperature even though it is accompanied by a contraction along the V 4+ -V 4+ bond direction, the crystallographic c-axis lattice parameter. Additionally, it is demonstrated that films grown at low substrate temperatures exhibit a relaxed state and a strongly reduced transition temperature. It is suggested that, besides thermal and epitaxial strain, growth-induced defects may strongly affect the electronic phase transition. The results of this work reveal the difficulty in extracting the intrinsic material response to strain, when the exact contribution of all strain sources cannot be effectively determined. The findings also bear implications on the limitations in obtaining the recently predicted novel semi-Dirac point phase in VO 2 /TiO 2 multilayer structures.

  7. Raman scattering and x-ray diffractometry studies of epitaxial TiO2 and VO2 thin films and multilayers on α-Al2O3(11 bar 20)

    International Nuclear Information System (INIS)

    Foster, C.M.; Chiarello, R.P.; Chang, H.L.M.; You, H.; Zhang, T.J.; Frase, H.; Parker, J.C.; Lam, D.J.

    1993-01-01

    Epitaxial thin films of TiO 2 and VO 2 single layers and TiO 2 /VO 2 multilayers were grown on (11 bar 20) sapphire (α-Al 2 O 3 ) substrates using the metalorganic chemical vapor deposition technique and were characterized using Raman scattering and four x-ray diffractometry. X-ray diffraction results indicate that the films are high quality single crystal material with well defined growth plane and small in-plane and out-of-plane mosaic. Single-layer films are shown to obey the Raman selection rules of TiO 2 and VO 2 single crystals. The close adherence to the Raman selection rules indicates the high degree of orientation of the films, both parallel and perpendicular to the growth plane. Selection rule spectra of two and three layer TiO 2 /VO 2 multilayers are dominated by the VO 2 layers with only minimal signature of the TiO 2 layers. Due to the low band gap of semiconducting vanadium dioxide, we attribute the strong signature of the VO 2 layers to resonant enhancement of the VO 2 Raman component accompanied with absorption of the both the incident and scattered laser light from the TiO 2 layers

  8. The relation between 25-hydroxyvitamin D with peak bone mineral density and body composition in healthy young adults

    NARCIS (Netherlands)

    Boot, Annemieke M.; Krenning, Eric P.; Keizer-Schrama, Sabine M. P. F. de Muinck

    Objective: The associations between peak bone mineral density (BMD) and body composition with 25 hydroxyvitamin D (25OHD) levels in healthy young adults were evaluated. Methods: The number of participants was 464; 347 women and 117 men. The mean age was 24.3 years (range 17-31 years). BMD of the

  9. Geologic Mapping in Nogal Peak Quadrangle: Geochemistry, Intrusive Relations and Mineralization in the Sierra Blanca Igneous Complex, New Mexico

    Science.gov (United States)

    Goff, F.; Kelley, S. A.; Lawrence, J. R.; Cikowski, C. T.; Krier, D. J.; Goff, C. J.; McLemore, V. T.

    2011-12-01

    Nogal Peak quadrangle is located in the northern Sierra Blanca Igneous Complex (SBIC) and contains most of the White Mountain Wilderness (geologic map is available at http://geoinfo.nmt.edu/publications/maps/geologic/ofgm/details.cfml?Volume=134). The geology of the quad consists of a late Eocene to Oligocene volcanic pile (Sierra Blanca Volcanics, mostly alkali basalt to trachyte) intruded by a multitude of dikes, plugs and three stocks: Rialto, 31.4 Ma (mostly syenite), Three Rivers, ca. 29 to 27 Ma (quartz syenite intruded by subordinate alkali granite), and Bonito Lake, 26.6 Ma (mostly monzonite). Three Rivers stock is partially surrounded by alkali rhyolites that geochemically resemble the alkali granites. The circular shape of the stock and surrounding rhyolites suggests they form the root of a probable caldera. SBIC rocks have compositions typical of those found within the Rocky Mountain alkaline belt and those associated with continental rift zone magmatism. Because the volcanic host rocks are deeply eroded, intrusive relations with the stocks are well exposed. Most contacts at stock margins are near vertical. Roof pendants are common near some contacts and stoped blocks up to 700 m long are found within the Three Rivers stock. Contacts, pendants and stoped blocks generally display some combination of hornfelsing, brecciation, fracturing, faulting and mineralization. Sierra Blanca Volcanics display hydrothermal alteration increasing from argillic in the NW sector of the quad to high-temperature porpylitic near stock margins. Retrograde phyllic alteration occurs within breccia pipes and portions of the stocks. Mineral deposits consist of four types: Placer Au, fissure veins (mostly Ag-Pb-Zn±Au), breccia pipes (Au-Mo-Cu), and porphyry Mo-Cu. A singular pipe on the SW margin of Bonito Lake stock contains sapphire-lazulite-alunite. Although Au has been intermittently mined in the quad since 1865, best production of Au originated around the turn of the last

  10. Testing the E(sub peak)-E(sub iso) Relation for GRBs Detected by Swift and Suzaku-WAM

    Science.gov (United States)

    Krimm, H. A.; Yamaoka, K.; Sugita, S.; Ohno, M.; Sakamoto, T.; Barthelmy, S. D.; Gehrels, N.; Hara, R.; Onda, K.; Sato, G.; hide

    2009-01-01

    One of the most prominent, yet controversial associations derived from the ensemble of prompt-phase observations of gamma-ray bursts (GRBs) is the apparent correlation in the source frame between the peak energy (E(sub peak)) of the nuF(nu) spectrum and the isotropic radiated energy, E(sub iso). Since most gamma-ray bursts (GRBs) have E(sub peak) above the energy range (15-150 keV) of the Burst Alert Telescope (BAT) on Swift, determining accurate E(sub peak) values for large numbers of Swift bursts has been difficult. However, by combining data from Swift/BAT and the Suzaku Wide-band All-Sky Monitor (WAM), which covers the energy range from 50-5000 keV, for bursts which are simultaneously detected ; one can accurately fit E(sub peak) and E(sub iso) and test the relationship between them for the Swift sample. Between the launch of Suzaku in July 2005 and the end of March 2009, there were 45 gamma-ray bursts (GRBs) which triggered both Swift/BAT and WAM and an additional 47 bursts which triggered Swift and were detected by WAM, but did not trigger. A BAT-WAM team has cross-calibrated the two instruments using GRBs, and we are now able to perform joint fits on these bursts to determine spectral parameters. For those bursts with spectroscopic redshifts.. we can also calculate the isotropic energy. Here we present the results of joint Swift/BAT-Suzaku/WAM spectral fits for 86 of the bursts detected by the two instruments. We show that the distribution of spectral fit parameters is consistent with distributions from earlier missions and confirm that Swift, bursts are consistent with earlier reported relationships between Epeak and isotropic energy. We show through time-resolved spectroscopy that individual burst pulses are also consistent with this relationship.

  11. Changes in peak fat oxidation in response to different doses of endurance training

    DEFF Research Database (Denmark)

    Larsen, Mads Rosenkilde; Reichkendler, M H; Auerbach, P

    2015-01-01

    enzymes determined by Western blotting. PFO increased in both MOD [1.2 mg/kg fat-free mass (FFM)/min, 95% confidence interval (CI): 0.08:2.3, P = 0.03] and HIGH (1.8 mg/kg FFM/min, CI: 0.6:2.9, P ..., and mitochondrial oxphos complexes II-V increased similarly in MOD and HIGH. Stepwise multiple linear regression analysis with backward elimination of individual variables correlated with changes in PFO revealed increases in cycling efficiency, FFM, and VO2 peak as the remaining associated variables. In conclusion......, PFO during exercise increased with both moderate- and high-dose endurance training. Increases in PFO were mainly predicted by changes in VO2 peak, FFM, and cycling efficiency, and less with skeletal muscle mitochondrial enzymes....

  12. The relation between 25-hydroxyvitamin D with peak bone mineral density and body composition in healthy young adults.

    Science.gov (United States)

    Boot, Annemieke M; Krenning, Eric P; de Muinck Keizer-Schrama, Sabine M P F

    2011-01-01

    The associations between peak bone mineral density (BMD) and body composition with 25 hydroxyvitamin D (25OHD) levels in healthy young adults were evaluated. The number of participants was 464; 347 women and 117 men. The mean age was 24.3 years (range 17-31 years). BMD of the lumbar spine, total body and femoral neck (FN) and body composition were measured by dual energy X-ray absorptiometry. Volumetric BMD, bone mineral apparent density (BMAD), of the lumbar spine and FN was calculated. In females, 25OHD level was positively associated with FN BMD and BMAD (both ppercentage body fat (pbody BMD and lean body mass (p=0.03 and p=0.01). 25OHD level is a determinant of peak BMD in both sexes. Vitamin D status was associated with body fat in females and with lean body mass in males.

  13. BMD in elite female triathletes is related to isokinetic peak torque without any association to sex hormone concentrations

    DEFF Research Database (Denmark)

    Helge, Eva Wulff; Melin, Anna; Waaddegaard, Mette

    2012-01-01

    Female endurance athletes suffering from low energy availability and reproductive hormonal disorders are at risk of low BMD. Muscle forces acting on bone may have a reverse site-specific effect. Therefore we wanted to test how BMD in female elite triathletes was associated to isokinetic peak torque...... (IPT) and reproductive hormone concentrations (RHC). A possible effect of oral contraceptives (OCON's) is taken into consideration....

  14. An electrochemical study of the systems Li1+-xV2O4 and Li1-xVO2 (0≤x≤1)

    International Nuclear Information System (INIS)

    De Picciotto, L.A.; Thackeray, M.M.; Pistoia, G.

    1988-01-01

    Electrochemical properties of the systems Li 1±x V 2 O 4 (0≤x≤1), Li 1-x VO 2 (0≤x 2 O 4 is reversible, which confirms that lithium may be cycled, topotactically, in and out of the Li 1+x V 2 O 4 spinel structure. Delithiation of the LiV 2 O 4 spinel is irreversible; during this process the vanadium ions migrate through the oxide layers. This results in a defect rocksalt phase, which can, in turn, be relithiated by a different mechanism. Lithium extraction for the layered compound LiVO 2 yields a structure similar to the delithiated LiV 2 O 4 product. The spinel-derived compounds Li 1 +-x/V 2 O 4 (0 -3 Ω -1 cm -1 at x=0 and 10 -6 Ω -1 cm -1 at x=1. Lithium diffusion rates in Li 1±x V 2 O 4 samples increase with lithiation from D=4x10 -10 cm 2 /s in LiV 2 O 4 to D=6x10 -8 cm 2 /s in Li 2 V 2 O 4 . Intermediate values of D are obtained in the delithiated compound Li 0.28 V 2 O 4 and in the layered oxide LiVO 2 ; significantly lower values of D, viz. 1x10 -11 cm 2 /s and 4x10 -11 cm 2 /s , are found in the spinels LiMn 2 O 4 and Fe 3 O 4 respectively. 28 refs.; 5 figs.; 1 table

  15. Observation of the spin gap in a S=1/2 alternating chain compound, high pressure phase of (VO)2P2O7

    International Nuclear Information System (INIS)

    Saito, Takashi; Azuma, Masaki; Fujita, Masaki; Takano, Mikio

    2001-01-01

    Inelastic neutron scattering data were collected on the high pressure phase of (VO) 2 P 2 O 7 , a S=1/2 Heisenberg antiferromagnetic alternating chain compound. The existence of a spin gap was confirmed, and the size was determined to be Δ=2.15(6) meV (=25.0(7) K). The theoretically predicted second gap (Δ'=2Δ) owing to a 2-magnon bound state was not observed. This is consistent with the high field magnetization measurement reported previously. (author)

  16. Oxygen uptake during peak graded exercise and single-stage fatigue tests of wheelchair propulsion in manual wheelchair users and the able-bodied.

    Science.gov (United States)

    Keyser, R E; Rodgers, M M; Gardner, E R; Russell, P J

    1999-10-01

    To determine if a single-stage, submaximal fatigue test on a wheelchair ergometer would result in higher than expected energy expenditure. An experimental survey design contrasting physiologic responses during peak graded exercise tests and fatigue tests. A rehabilitation science laboratory that included a prototypical wheelchair ergometer, open-circuit spirometry system, and heart rate monitor. Nine able-bodied non-wheelchair users (the NWC group: 6 men and 3 women, mean +/- SD age 30 +/- 7yrs) and 15 manual wheelchair users (the WC group: 12 men and 3 women, age 40 +/- 9yrs, time in wheelchair 16 +/- 9yrs). No subject had any disease, medication regimen, or upper body neurologic, orthopedic, or other condition that would limit wheelchair exercise. Peak oxygen uptake (VO2) for graded exercise testing and during fatigue testing, using a power output corresponding to 75% peak aerobic capacity on graded exercise test. In the WC group, VO2 at 6 minutes of fatigue testing was not significantly different from peak VO2. In the NWC group, VO2 was similar to the expected level throughout fatigue testing. Energy expenditure was higher than expected in the WC group but not in the NWC group. Fatigue testing may provide a useful evaluation of cardiorespiratory status in manual wheelchair users.

  17. Relative Economic Merits of Storage and Combustion Turbines for Meeting Peak Capacity Requirements under Increased Penetration of Solar Photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Denholm, Paul [National Renewable Energy Lab. (NREL), Golden, CO (United States); Diakov, Victor [National Renewable Energy Lab. (NREL), Golden, CO (United States); Margolis, Robert [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-09-01

    Batteries with several hours of capacity provide an alternative to combustion turbines for meeting peak capacity requirements. Even when compared to state-of-the-art highly flexible combustion turbines, batteries can provide a greater operational value, which is reflected in a lower system-wide production cost. By shifting load and providing operating reserves, batteries can reduce the cost of operating the power system to a traditional electric utility. This added value means that, depending on battery life, batteries can have a higher cost than a combustion turbine of equal capacity and still produce a system with equal or lower overall life-cycle cost. For a utility considering investing in new capacity, the cost premium for batteries is highly sensitive to a variety of factors, including lifetime, natural gas costs, PV penetration, and grid generation mix. In addition, as PV penetration increases, the net electricity demand profile changes, which may reduce the amount of battery energy capacity needed to reliably meet peak demand.

  18. Multiple testing issues in discriminating compound-related peaks and chromatograms from high frequency noise, spikes and solvent-based nois in LC-MS data sets

    NARCIS (Netherlands)

    Nyangoma, S.O.; Van Kampen, A.A.; Reijmers, T.H.; Govorukhina, N.I; van der Zee, A.G.; Billingham, I.J; Bischoff, Rainer; Jansen, R.C.

    2007-01-01

    Multiple testing issues in discriminating compound-related peaks and chromatograms from high frequency noise, spikes and solvent-based noise in LC-MS data sets.Nyangoma SO, van Kampen AA, Reijmers TH, Govorukhina NI, van der Zee AG, Billingham LJ, Bischoff R, Jansen RC. University of Birmingham.

  19. Pain severity is associated with muscle strength and peak oxygen uptake in adults with fibromyalgia

    Directory of Open Access Journals (Sweden)

    Hooten WM

    2014-05-01

    Full Text Available W Michael Hooten,1,2 Jolene M Smith,3 Jason S Eldrige,1 David A Olsen,3 W David Mauck,1 Susan M Moeschler11Department of Anesthesiology, 2Department of Psychiatry and Psychology, Mayo Clinic College of Medicine, 3Mayo School of Graduate Medical Education, Rochester, MN, USABackground: The associations between pain, lower extremity strength, and aerobic conditioning have not been widely investigated in adults with fibromyalgia (FM. The principle objective of this study was to investigate the relationship between pain severity and knee strength in patients seeking treatment for FM. A secondary objective was to investigate the relationship between pain scores and aerobic conditioning.Methods: Three measures of knee strength (isokinetic extensor, isokinetic flexor, isometric extensor were quantified in the dominant leg of 69 adults with FM using a dynamometer at speeds of 60 degrees per second (60°/s and 180°/s. Peak oxygen uptake (VO2 was assessed using a cycle ergometer, and pain was assessed using the pain severity subscale of the Multidimensional Pain Inventory.Results: In univariable linear regression analyses using pain severity as the dependent variable, lesser values of isokinetic knee extensor strength at 60°/s (P=0.041 and 180°/s (P=0.010, isokinetic knee flexor strength at 60°/s (P=0.028 and 180°/s (P=0.003, and peak VO2 uptake (P=0.031 were predictive of greater pain severity scores. In multiple variable linear regression models adjusted for age, sex, body mass index, and opioid use, the following associations retained statistical significance; isokinetic knee extensor strength at 60°/s (P=0.020 and 180°/s (P=0.003, isokinetic knee flexor strength at 60°/s (P=0.015 and 180°/s (P=0.001, and peak VO2 uptake (P=0.014. However, no significant associations were found between pain severity and isometric knee extensor strength.Conclusion: The main findings from this study were that lesser values of isokinetic knee strength and peak VO

  20. Model Related Estimates of time dependent quantiles of peak flows - case study for selected catchments in Poland

    Science.gov (United States)

    Strupczewski, Witold G.; Bogdanowich, Ewa; Debele, Sisay

    2016-04-01

    Under Polish climate conditions the series of Annual Maxima (AM) flows are usually a mixture of peak flows of thaw- and rainfall- originated floods. The northern, lowland regions are dominated by snowmelt floods whilst in mountainous regions the proportion of rainfall floods is predominant. In many stations the majority of AM can be of snowmelt origin, but the greatest peak flows come from rainfall floods or vice versa. In a warming climate, precipitation is less likely to occur as snowfall. A shift from a snow- towards a rain-dominated regime results in a decreasing trend in mean and standard deviations of winter peak flows whilst rainfall floods do not exhibit any trace of non-stationarity. That is why a simple form of trends (i.e. linear trends) are more difficult to identify in AM time-series than in Seasonal Maxima (SM), usually winter season time-series. Hence it is recommended to analyse trends in SM, where a trend in standard deviation strongly influences the time -dependent upper quantiles. The uncertainty associated with the extrapolation of the trend makes it necessary to apply a relationship for trend which has time derivative tending to zero, e.g. we can assume a new climate equilibrium epoch approaching, or a time horizon is limited by the validity of the trend model. For both winter and summer SM time series, at least three distributions functions with trend model in the location, scale and shape parameters are estimated by means of the GAMLSS package using the ML-techniques. The resulting trend estimates in mean and standard deviation are mutually compared to the observed trends. Then, using AIC measures as weights, a multi-model distribution is constructed for each of two seasons separately. Further, assuming a mutual independence of the seasonal maxima, an AM model with time-dependent parameters can be obtained. The use of a multi-model approach can alleviate the effects of different and often contradictory trends obtained by using and identifying

  1. Final Environmental Statement related to the operation of Comanche Peak Steam Electric Station, Units 1 and 2 (Docket Nos. 50-445 and 50-446)

    International Nuclear Information System (INIS)

    1989-10-01

    In September 1981, the staff of the Nuclear Regulatory Commission (NRC) issued its Final Environmental Statement (NUREG-0775) related to the operation of Comanche Peak Steam Electric Station, Units 1 and 2 (Docket Nos. 50-445 and 50-446), located in Somervell County, Texas, approximately 40 miles southwest of Fort Worth, Texas. The NRC has prepared this supplement to NUREG-0775 to present its evaluation of the alternative of operating Comanche Peak with the installation of further severe-accident-mitigation design features. The NRC has discovered no substantial changes in the proposed action as previously evaluated in the Final Environmental Statement that are relevant to environmental concerns and bearing on the licensing of Comanche Peak Steam Electric Station, Units 1 and 2. 6 refs., 3 tabs

  2. Spectroscopic and optical properties of the VO2+ ion doped TeO2-TiO2-ZnO-Nb2O5 glass system

    Science.gov (United States)

    Swapna; Upender, G.; Sreenivasulu, V.; Prasad, M.

    2016-04-01

    Studies such as optical absorption, Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, Electron paramagnetic resonance (EPR) spectroscopy and Differential scanning calorimetry (DSC) were carried out on VO2+ ion doped TeO2-TiO2-ZnO-Nb2O5 glass system. Raman and FTIR spectra of the glasses revealed the presence of [TeO3], [TeO4] and [NbO6] structural units in the glass network. The Urbach energy (Δ E), cut-off wavelength (λ c ), optical band gap ( E opt ), optical basicity (Λ) and electron polarizability ( α) of the glasses were determined from optical absorption studies. The density ( ρ), molar volume ( V m ), oxygen molar volume ( V o ) and refractive index ( n) were also measured. Spin-Hamiltonian parameters were calculated from the EPR studies. When Nb2O5 was increased at the expense of ZnO, the density, optical band gap and Urbach energy of the glasses increased, and the electronic polarizability and optical basicity decreased. The EPR spectra clearly showed that vanadium was in the glass as VO2+ and occupied octahedral sites with tetrahedral compression. Spin-Hamiltonian parameters g‖ and g⊥ decreased as Nb2O5 content increased in the glass. The glass transition temperature ( T g ) also increased with increasing Nb2O5 content in the glass.

  3. Influence of VO2+ ions on structural and optical properties of potassium succinate-succinic acid single crystal for non-linear optical applications

    Science.gov (United States)

    Juliet sheela, K.; Subramanian, P.

    2018-04-01

    A transparent and good optical quality semi organic single crystal of vanadium doped potassium succinate-succinic acid (KSSA) was synthesized by slow evaporation technique at room temperature. The structural perfection was supported by the powder XRD of the KSSA-VO2+ single crystal. Optical behavior of the material was discovered from the absorption and transmission spectra of UV-vis-NIR characterization. Functional group and presence of metal ion in the specimen are depicted from FTIR traces. From the photoluminescence studies, emission of wavelength in the violet region (418 nm) at the excitation of 243 nm could be ascertained. EDAX, SEM measurements identify presence of elements and pictures the step-line growth and the imperfection presents in the grown crystal. EPR analysis extracts the information about the local site symmetry around the impurity ion, molecular orbital coefficients, admixture coefficients and ground state wave function of VO2+ doped KSSA single crystal. Second harmonic generation (SHG) efficiency of the grown crystal was investigated to explore the NLO characteristic of the material.

  4. Nature of phase transitions in ammonium oxofluorovanadates, a vibrational spectroscopy study of (NH4)3VO2F4 and (NH4)3VOF5.

    Science.gov (United States)

    Gerasimova, Yu V; Oreshonkov, A S; Laptash, N M; Vtyurin, A N; Krylov, A S; Shestakov, N P; Ershov, A A; Kocharova, A G

    2017-04-05

    Two ammonium oxofluorovanadates, (NH 4 ) 3 VO 2 F 4 and (NH 4 ) 3 VOF 5 , have been investigated by temperature-dependent infrared and Raman spectroscopy methods to determine the nature of phase transitions (PT) in these compounds. Dynamics of quasioctahedral groups was simulated within the framework of semi-empirical approach, which justified the cis-conformation of VO 2 F 4 3- (C 2v ) and the C 4v geometry of VOF 5 3- . The observed infrared and Raman spectra of both compounds at room temperature (RT) revealed the presence at least of two crystallographically independent octahedral groups. The first order PT at elevated temperatures is connected with a complete dynamic disordering of these groups with only single octahedral state. At lower temperatures, the octahedra are ordered and several octahedral states appear. This PT is the most pronounced in the case of (NH 4 ) 3 VOF 5 , when at least seven independent VOF 5 3- octahedra are present in the structure below 50K, in accordance with the Raman spectra. Ammonium groups do not take part in PTs at higher and room temperatures but their reorientational motion freezes at lower temperatures. Copyright © 2017. Published by Elsevier B.V.

  5. Sex differences in the effects of 12 weeks sprint interval training on body fat mass and the rates of fatty acid oxidation and VO2max during exercise.

    Science.gov (United States)

    Bagley, Liam; Slevin, Mark; Bradburn, Steven; Liu, Donghui; Murgatroyd, Chris; Morrissey, George; Carroll, Michael; Piasecki, Mathew; Gilmore, William S; McPhee, Jamie S

    2016-01-01

    The purpose of this study was to examine whether very short duration, very high intensity sprint interval training (SIT) leads to loss of body fat mass in association with improvements to VO 2 max and fatty acid oxidation, and to assess the extent of sex dimorphism in these physiological responses. A total of 24 men and 17 women (mean (SEM) age: 39 (±2) years; body mass index 24.6 (0.6)) completed measurements of the maximal rate of oxygen uptake (VO 2 max) and fatty acid oxidation (FATmax). Body fat and lean mass were measured by dual emission x-ray absorptiometry, and fasting blood lipid, glucose and insulin profiles were assessed before and after training. SIT consisted of 4×20 s sprints on a cycle ergometer at approximately 175% VO 2 max, three times per week for 12 weeks. Fat mass decreased by 1.0 kg, although men lost statistically significantly more fat than women both when expressed in Kg and as % body fat. VO 2 max increased by around 9%, but women improved VO 2 max significantly more than men. FATmax improved by around 13%, but fasting plasma glucose, insulin, total triglyceride, total cholesterol and high-density lipoprotein (HDL) did not change after training, while low-density lipoprotein decreased by 8% (p=0.028) and the HDL:Total Cholesterol ratio improved by 6%. There were no sex differences in these metabolic responses to training. These results show lower body fat %, and higher rates of fatty acid oxidation and VO 2 max after 12 weeks of training for just 4 min per week. Notably, women improved VO 2 max more than men, while men lost more fat than women.

  6. Sex differences in the effects of 12 weeks sprint interval training on body fat mass and the rates of fatty acid oxidation and VO2max during exercise

    Science.gov (United States)

    Bagley, Liam; Slevin, Mark; Bradburn, Steven; Liu, Donghui; Murgatroyd, Chris; Morrissey, George; Carroll, Michael; Piasecki, Mathew; Gilmore, William S; McPhee, Jamie S

    2016-01-01

    Background The purpose of this study was to examine whether very short duration, very high intensity sprint interval training (SIT) leads to loss of body fat mass in association with improvements to VO2max and fatty acid oxidation, and to assess the extent of sex dimorphism in these physiological responses. Methods A total of 24 men and 17 women (mean (SEM) age: 39 (±2) years; body mass index 24.6 (0.6)) completed measurements of the maximal rate of oxygen uptake (VO2max) and fatty acid oxidation (FATmax). Body fat and lean mass were measured by dual emission x-ray absorptiometry, and fasting blood lipid, glucose and insulin profiles were assessed before and after training. SIT consisted of 4×20 s sprints on a cycle ergometer at approximately 175% VO2max, three times per week for 12 weeks. Results Fat mass decreased by 1.0 kg, although men lost statistically significantly more fat than women both when expressed in Kg and as % body fat. VO2max increased by around 9%, but women improved VO2max significantly more than men. FATmax improved by around 13%, but fasting plasma glucose, insulin, total triglyceride, total cholesterol and high-density lipoprotein (HDL) did not change after training, while low-density lipoprotein decreased by 8% (p=0.028) and the HDL:Total Cholesterol ratio improved by 6%. There were no sex differences in these metabolic responses to training. Conclusions These results show lower body fat %, and higher rates of fatty acid oxidation and VO2max after 12 weeks of training for just 4 min per week. Notably, women improved VO2max more than men, while men lost more fat than women. PMID:27900150

  7. Relative biological effectiveness in a proton spread-out Bragg peak formed by pencil beam scanning mode

    Czech Academy of Sciences Publication Activity Database

    Michaelidesová, Anna; Vachelová, Jana; Puchalská, M.; Pachnerová Brabcová, Kateřina; Vondráček, V.; Sihver, L.; Davídková, Marie

    2017-01-01

    Roč. 40, č. 2 (2017), s. 359-368 ISSN 0158-9938 R&D Projects: GA ČR(CZ) GBP108/12/G108 Institutional support: RVO:61389005 Keywords : Relative biological effectiveness * Proton therapy * Clonogennic assay * Micronuclei assay * Monte Carlo simulations * Scanning beam Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders OBOR OECD: Nuclear physics Impact factor: 1.171, year: 2016

  8. Theoretical studies of the optical and EPR spectra for VO^{2+} in Na_3C_6H_5O_7·2H_2O single crystal

    Directory of Open Access Journals (Sweden)

    Ch.-Y. Li

    2015-06-01

    Full Text Available On the basis of the perturbation formulas for a d^1 configuration ion in a tetragonal crystal field, the three optical absorption bands and electron paramagnetic resonance (EPR parameters (g factors g_i and hyperfine structure constants A_i for i = || and ⊥, respectively of VO^{2+} in Na_3C_6H_5O_7·2H_2O (TSCD single crystals were studied using the perturbation theory method. By simulating the calculated optical and EPR spectra to the observed values, local structure parameters and negative signs of the hyperfine structure constants A_i of the octahedral (VO_6^{8-} cluster in TSCD single crystal can be obtained.

  9. Relação entre a variabilidade da frequência cardíaca e VO 2pico em mulheres ativas

    OpenAIRE

    Tamburús, Nayara Yamada; Rebelo, Ana Cristina Silva; César, Marcelo de Castro; Catai, Aparecida Maria; Takahashi, Anielle Cristhine de Medeiros; Andrade, Carolina Pieroni; Porta, Alberto; Silva, Ester da

    2014-01-01

    OBJETIVO: Ava+liar a associação entre os índices da variabilidade da frequência cardíaca (VFC) e a aptidão cardiorrespiratória.MÉTODOS: Sessenta e duas mulheres (idade 22,1 ± 3,3 anos) foram divididas em quatro grupos: treinamento aeróbio (AER, n = 15), treinamento de força (FOR, n = 13), treinamento combinado (aeróbio e força) (AER+FOR, n = 15) e controle (C, n = 19). O teste cardiopulmonar foi realizado para avaliar a aptidão cardiorrespiratória a partir do consumo de oxigênio pico (VO2pico...

  10. Self Assembly and Properties of C:WO3 Nano-Platelets and C:VO2/V2O5 Triangular Capsules Produced by Laser Solution Photolysis

    Directory of Open Access Journals (Sweden)

    Sideras-Haddad E

    2009-01-01

    Full Text Available Abstract Laser photolysis of WCl6 in ethanol and a specific mixture of V2O5 and VCl3 in ethanol lead to carbon modified vanadium and tungsten oxides with interesting properties. The presence of graphene’s aromatic rings (from the vibrational frequency of 1,600 cm−1 together with C–C bonding of carbon (from the Raman shift of 1,124 cm−1 present unique optical, vibrational, electronic and structural properties of the intended tungsten trioxide and vanadium dioxide materials. The morphology of these samples shows nano-platelets in WO x samples and, in VO x samples, encapsulated spherical quantum dots in conjunction with fullerenes of VO x . Conductivity studies revealed that the VO2/V2O5 nanostructures are more sensitive to Cl than to the presence of ethanol, whereas the C:WO3 nano-platelets are more sensitive to ethanol than atomic C.

  11. Imaging Nanometer Phase Coexistence at Defects During the Insulator-Metal Phase Transformation in VO2 Thin Films by Resonant Soft X-ray Holography.

    Science.gov (United States)

    Vidas, Luciana; Günther, Christian M; Miller, Timothy A; Pfau, Bastian; Perez-Salinas, Daniel; Martínez, Elías; Schneider, Michael; Gührs, Erik; Gargiani, Pierluigi; Valvidares, Manuel; Marvel, Robert E; Hallman, Kent A; Haglund, Richard F; Eisebitt, Stefan; Wall, Simon

    2018-05-18

    We use resonant soft X-ray holography to image the insulator-metal phase transition in vanadium dioxide with element and polarization specificity and nanometer spatial resolution. We observe that nanoscale inhomogeneity in the film results in spatial-dependent transition pathways between the insulating and metallic states. Additional nanoscale phases form in the vicinity of defects which are not apparent in the initial or final states of the system, which would be missed in area-integrated X-ray absorption measurements. These intermediate phases are vital to understand the phase transition in VO 2 , and our results demonstrate how resonant imaging can be used to understand the electronic properties of phase-separated correlated materials obtained by X-ray absorption.

  12. Self assembly and properties of C:WO3 nano-platelets and C:VO2/V2O5 triangular capsules produced by laser solution photolysis

    CSIR Research Space (South Africa)

    Mwakikunga, BW

    2010-01-01

    Full Text Available -Structured Materials, P. O. Box 395, Pretoria, South Africa 123 Nanoscale Res Lett (2010) 5:389–397 DOI 10.1007/s11671-009-9494-4 coherent, intense and almost monochromatic laser light allows it to be tuned to selectively dissociate specific bonds in a precursor... in the current set of experiments. 390 Nanoscale Res Lett (2010) 5:389–397 123 2WðO � C2H5Þ6��! 248nm CxWO3�y þ . . . 2VðO � C2H5Þ4��! 248nm CxVO2þy þ . . . ð3Þ When the same precursors are irradiated with the 248-nm beam from the KrF excimer laser, the W(OR)6...

  13. Structural, thermal and optical properties of TeO2-ZnO-CdO-BaO glasses doped with VO(2+).

    Science.gov (United States)

    Sreenivasulu, V; Upender, G; Chandra Mouli, V; Prasad, M

    2015-09-05

    The glasses with composition 64TeO2-15ZnO-(20-x)CdO-xBaO-1V2O5 (0⩽x⩽20 mol%) were prepared by conventional melt quenching technique. X-ray diffraction analysis was used to confirm the amorphous nature of the glasses. The optical absorption studies revealed that the cut-off wavelength (λα) decreases while optical band gap energy (Eopt) and Urbach energy (ΔE) values increase with an increase of BaO content. Refractive index (n) evaluated from Eopt was found to decrease with an increase of BaO content. The physical parameters such as density (ρ), molar volume (Vm), oxygen packing density (OPD), optical basicity (Λ), molar refraction (Rm), and metallization criterion (M) evaluated and discussed. FTIR and Raman spectroscopic studies showed that the glass network consists of TeO4, TeO3+1/TeO3 and ZnO4 units as basic structural units. The glass transition temperature (Tg) of glass sample, onset crystallization temperature (To) and thermal stability ΔT were determined from Differential Scanning Calorimetry (DSC). Using electron paramagnetic resonance (EPR) spectra of vanadium glasses the spin Hamiltonian parameters and dipolar hyperfine coupling parameters of VO(2+) ions were calculated. It was found that V(4+) ions in these glasses exist as VO(2+) in octahedral coordination with a tetragonal distortion and have C4V symmetry with ground state dxy. Tetragonality (Δg∥/Δg⊥) of vanadium ion sites exhibited non-linear variation with BaO content. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. No association of the polymorphisms of the frizzled-related protein gene with peak bone mineral density in Chinese nuclear families

    Directory of Open Access Journals (Sweden)

    Yue Hua

    2010-01-01

    Full Text Available Abstract Background The Wnt/beta-catenin signaling pathway plays an important role in skeletal development. Polymorphisms of frizzled-related protein (FRZB, an antagonist of this pathway, may generate variations in bone mineral density (BMD. In this study, we analyzed the association between FRZB genotypes and peak BMD variation in the spines and hips of two relatively large samples of Chinese female-offspring and male-offspring nuclear families. Methods We recruited 1,260 subjects from 401 female-offspring nuclear families and 1,296 subjects from 427 male-offspring nuclear families and genotyped four tagging single nucleotide polymorphisms (tagSNPs (rs6433993, rs409238, rs288324, and rs4666865 spanning the entire FRZB gene. The SNPs rs288326 and rs7775, which are associated with hip osteoarthritis, were not selected in this study because of their low minor allele frequencies (MAFs in Chinese people. The quantitative transmission disequilibrium test (QTDT was used to analyze the association between each SNP and haplotype with peak BMD in female- and male-offspring nuclear families. Results In the female-offspring nuclear families, we found no evidence of an association between either single SNPs or haplotypes and peak BMD in the spine or hip. In the male-offspring nuclear families, no within-family association was observed for either SNPs or haplotypes, although a significant total association was found between rs4666865 and spine BMD (P = 0.0299. Conclusion Our results suggest that natural variation in FRZB is not a major contributor to the observed variability in peak BMD in either Chinese females or males. Because ethnic differences in the FRZB genotypes may exist, other studies in different population are required to confirm such results.

  15. In healthy elderly postmenopausal women variations in BMD and BMC at various skeletal sites are associated with differences in weight and lean body mass rather than by variations in habitual physical activity, strength or VO2max.

    Science.gov (United States)

    Schöffl, I; Kemmler, W; Kladny, B; Vonstengel, S; Kalender, W A; Engelke, K

    2008-01-01

    The objective of this study was an integrated cross-sectional investigation for answering the question whether differences in bone mineral density in elderly postmenopausal women are associated with differences in habitual physical activity and unspecific exercise levels. Two hundred and ninety nine elderly women (69-/+3 years), without diseases or medication affecting bone metabolism were investigated. The influence of weight, body composition and physical activity on BMD was measured at multiple sites using different techniques (DXA, QCT, and QUS). Physical activity and exercise level were assessed by questionnaire, maximum strength of the legs and aerobic capacity. Variations in physical activity or habitual exercise had no effect on bone. The only significant univariate relation between strength/VO(2)max and BMD/BMC that remained after adjusting for confounding variables was between arm BMD (DXA) and hand-grip strength. The most important variable for explaining BMD was weight and for cortical BMC of the femur (QCT) lean body mass. Weight and lean body mass emerge as predominant predictors of BMD in normal elderly women, whereas the isolated effect of habitual physical activity, unspecific exercise participation, and muscle strength on bone parameters is negligible. Thus, an increase in the amount of habitual physical activity will probably have no beneficial impact on bone.

  16. The relation of double peaks, observed in quartz hydride atomizers, to the fate of free analyte atoms in the determination of arsenic and selenium by atomic absorption spectrometry

    International Nuclear Information System (INIS)

    D'Ulivo, Alessandro; Dedina, Jiri

    2002-01-01

    The mechanism at the origin of double peaks formation in quartz hydride atomizers were investigated by continuous flow hydride generation atomic absorption spectrometry. Arsenic and selenium were used as model analytes. The effect of atomization mode (flame-in-gas-shield (FIGS), miniature diffusion flame and double flame (DF)) and some experimental parameters as oxygen supply rate for microflame and the distance from atomization to free atoms detection point, were investigated on the shape of both analytical signals and calibration graphs. Rollover of calibration graphs and double peak formation are strictly related each to the other and could be observed only in FIGS atomizer mode under some particular conditions. A mechanism based on incomplete atomization of hydrides cannot explain the collected experimental evidences because the microflame of FIGS is able to produce quantitative atomization of large amount of hydrides even at supply rate of oxygen close to extinction threshold of microflame. The heterogeneous gas-solid reactions between finely dispersed particles, formed by free atom recombination, and the free atoms in the gaseous phase are at the origin of double peak formation

  17. Exponential Increase in Relative Biological Effectiveness Along Distal Edge of a Proton Bragg Peak as Measured by Deoxyribonucleic Acid Double-Strand Breaks

    Energy Technology Data Exchange (ETDEWEB)

    Cuaron, John J., E-mail: cuaronj@mskcc.org [Memorial Sloan Kettering Cancer Center, New York, New York (United States); Chang, Chang [Texas Center for Proton Therapy, Irving, Texas (United States); Lovelock, Michael; Higginson, Daniel S. [Memorial Sloan Kettering Cancer Center, New York, New York (United States); Mah, Dennis [Procure Proton Therapy Center, Somerset, New Jersey (United States); Cahlon, Oren; Powell, Simon [Memorial Sloan Kettering Cancer Center, New York, New York (United States)

    2016-05-01

    Purpose: To quantify the relative biological effectiveness (RBE) of the distal edge of the proton Bragg peak, using an in vitro assay of DNA double-strand breaks (DSBs). Methods and Materials: U2OS cells were irradiated within the plateau of a spread-out Bragg peak and at each millimeter position along the distal edge using a custom slide holder, allowing for simultaneous measurement of physical dose. A reference radiation signal was generated using photons. The DNA DSBs at 3 hours (to assess for early damage) and at 24 hours (to assess for residual damage and repair) after irradiation were measured using the γH2AX assay and quantified via flow cytometry. Results were confirmed with clonogenic survival assays. A detailed map of the RBE as a function of depth along the Bragg peak was generated using γH2AX measurements as a biological endpoint. Results: At 3 hours after irradiation, DNA DSBs were higher with protons at every point along the distal edge compared with samples irradiated with photons to similar doses. This effect was even more pronounced after 24 hours, indicating that the impact of DNA repair is less after proton irradiation relative to photons. The RBE demonstrated an exponential increase as a function of depth and was measured to be as high as 4.0 after 3 hours and as high as 6.0 after 24 hours. When the RBE-corrected dose was plotted as a function of depth, the peak effective dose was extended 2-3 mm beyond what would be expected with physical measurement. Conclusions: We generated a highly comprehensive map of the RBE of the distal edge of the Bragg peak, using a direct assay of DNA DSBs in vitro. Our data show that the RBE of the distal edge increases with depth and is significantly higher than previously reported estimates.

  18. Safety evaluation report related to the operation of Comanche Peak Steam Electric Station, Units 1 and 2 (Docket Nos. 50-445 and 50-446)

    International Nuclear Information System (INIS)

    1988-11-01

    Supplement 19 to the Safety Evaluation Report related to the operation of the Comanche Peak Steam Electric Station (CPSES), Units 1 and 2 (NUREG-0797), has been prepared by the Office of Special Projects of the US Nuclear Regulatory Commission (NRC). The facility is located in Somervell County, Texas, approximately 40 miles southwest of Fort Worth, Texas. This supplement presents the staff's evaluation of the Texas Utilities Electric Company's (lead applicant's) corrective action program (CAP) related to equipment qualification. The scope and methodology for the CAP workscope, as summarized in Revision 0 to the Equipment Qualification Project Status Report and as detailed in related documents, were developed to resolve various issues raised by the Comanche Peak Response Team (CPRT) and the NRC staff to ensure that plant equipment is appropriately environmentally and/or seismically and dynamically qualified and documented in accordance with the validated plant design resulting from other CAP scopes of work for Unit 1 and areas common to Units 1 and 2. The staff concludes that the CAP workscope for equipment qualification provides a comprehensive program for resolving the concerns identified by the CPRT and the NRC staff, including issues raised in the Comanche Peak Safety Evaluation Report and its supplements, and its implementation will ensure that the environmental and/or seismic and dynamic qualification of equipment at CPSES satisfies the validated plant design and the applicable requirements of 10 CFR Part 50. As is routine staff practice, the NRC staff will verify the adequacy of implementation of the environmental and seismic and dynamic equipment qualification program at CPSES during inspections that will take place before fuel loading. 97 refs

  19. Safety evaluation report related to the operation of Comanche Peak Steam Electric Station, Units 1 and 2: Docket Nos. 50-445 and 50-446

    International Nuclear Information System (INIS)

    1988-07-01

    Supplement 15 to the Safety Evaluation Report related to the operation of the Comanche Peak Steam Electric Station (CPSES), Units 1 and 2 (NUREG-0797), has been prepared by the Office of Special Projects of the US Nuclear Regulatory Commission (NRC). The facility is located in Somervell County, Texas, approximately 40 miles southwest of Fort Worth, Texas. This supplement presents the staff's evaluation of the applicant's Corrective Action Program (CAP) related to the design of cable trays and cable tray hangers. The scope and methodologies for the CAP workscope as summarized in Revision O to the cable tray and cable tray hanger project status report and as detailed in related documents referenced in this evaluation were developed to resolve various design issues raised by the Atomic Safety and Licensing Board (ASLB) the intervenor, Citizens Association for Sound Energy (CASE); the Comanche Peak Response Team (CPRT); CYGNA Energy Services (CYGNA); and the NRC staff. The NRC staff concludes that the CAP workscope for cable trays and cable tray hangers provides a comprehensive program for resolving the associated technical concerns identified by the ASLB, CASE, CPRT, CYGNA, and the NRC staff and its implementation ensures that the design of cable trays and cable tray hangers at CPSES satisfies the applicable requirements of 10 CFR Part 50

  20. Safety evaluation report related to the operation of Comanche Peak Steam Electric Station, Units 1 and 2 (Docket Nos. 50-445 and 50-446)

    International Nuclear Information System (INIS)

    1988-03-01

    Supplement 14 to the Safety Evaluation Report related to the operation of the Comanche Peak Stam Electric Station (CPSES), Units 1 and 2 (NUREG-0797), has been prepared by the Office of Special Projects of the US Nuclear Regulatory Commission (NRC). The facility is located in Somerville County, Texas, approximately 40 miles southwest of Fort Worth, Texas. This supplement presents the staff's evaluation of the applicants' Corrective Action Program (CAP0 related to large ans small bore piping and pipe supports. The scope and methodologies for CAP workshop as summarized in revision O to the large and small bore piping project status reports and as detailed in related documents referenced in this evaluation were developed to resolve various design issues raised by the Atomic Safety and Licensing Board (ASLB);the intervenor, Citizens Association for Sound Energy (CASE);the Camanche Peak Response Team (CPRT);SYGNA Energy Services (CYGNA);and the NRC staff. The NRC staff concludes that the CAP workscopes for large and small bore piping provide a comprehensive program for resolving the associated technical concerns identified by the ASLB, CASE, CPRT, CYGNA, and the NRC staff and their implementation ensures that the design of large and small bore piping and pipe supports at CPSES satisfies the applicable requirements of 10 CFR 50

  1. 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

  2. Trends in physical activity, health-related fitness, and gross motor skills in children during a two-year comprehensive school physical activity program.

    Science.gov (United States)

    Brusseau, Timothy A; Hannon, James C; Fu, You; Fang, Yi; Nam, Kahyun; Goodrum, Sara; Burns, Ryan D

    2018-01-06

    The purpose of this study was to examine the trends in school-day step counts, health-related fitness, and gross motor skills during a two-year Comprehensive School Physical Activity Program (CSPAP) in children. Longitudinal trend analysis. Participants were a sample of children (N=240; mean age=7.9±1.2 years; 125 girls, 115 boys) enrolled in five low-income schools. Outcome variables consisted of school day step counts, Body Mass Index (BMI), estimated VO 2 Peak , and gross motor skill scores assessed using the Test of Gross Motor Development-3rd Edition (TGMD-3). Measures were collected over a two-year CSPAP including a baseline and several follow-up time-points. Multi-level mixed effects models were employed to examine time trends on each continuous outcome variable. Markov-chain transition models were employed to examine time trends for derived binary variables for school day steps, BMI, and estimated VO 2 Peak . There were statistically significant time coefficients for estimated VO 2 Peak (b=1.10mL/kg/min, 95% C.I. [0.35mL/kg/min-2.53mL/kg/min], p=0.009) and TGMD-3 scores (b=7.8, 95% C.I. [6.2-9.3], p<0.001). There were no significant changes over time for school-day step counts or BMI. Boys had greater change in odds of achieving a step count associating with 30min of school day MVPA (OR=1.25, 95% C.I. [1.02-1.48], p=0.044). A two-year CSPAP related to increases in cardio-respiratory endurance and TGMD-3 scores. School day steps and BMI were primarily stable across the two-year intervention. Copyright © 2018 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  3. Safety evaluation report related to the operation of Comanche Peak Steam Electric Station, Units 1 and 2: Docket No. 50-445 and 50-446

    International Nuclear Information System (INIS)

    1988-11-01

    Supplement 20 to the Safety Evaluation Report related to the operation of the Comanche Peak Steam Electric Station (CPSES), Units 1 and 2 (NUREG-0797), has been prepared by the Office of Special Projects of the US Nuclear Regulatory Commission (NRC). The facility is located in Somervell County, Texas, approximately 40 miles southwest of Fort Worth, Texas. This supplement presents the staff's evaluation of CPRT implementation of the Comanche Peak Response Team (CPRT) Program Plan and the issue-specific action plans (ISAPs), as well as the CPRT's investigations to determine the adequacy of various types of programs and hardware at CPSES. The results and conclusions of the CPRT activities are documented in a results report for each ISAP, a Collective Evaluation Report (CER), and a Collective Significance Report (CSR). This supplement also presents the staff's safety evaluation of TU Electric's root cause assessment of past CPSES design deficiencies and weaknesses. The NRC staff concludes that the CPRT has adequately implemented its investigative activities related to the design, construction, construction quality assurance/quality control, and testing at CPSES. The NRC staff further concludes that the CPRT evaluation of the results of its investigation is thorough and complete and its recommendations for corrective actions are sufficient to resolve identified deficiencies

  4. Safety Evaluation Report related to the operation of Comanche Peak Steam Electric Station, Units 1 and 2 (Docket Nos. 50-445 and 50-446)

    International Nuclear Information System (INIS)

    1990-02-01

    Supplement 23 to the Safety Evaluation Report related to the operation of the Comanche Peak Steam Electric Station (CPSES), Units 1 and 2 (NUREG-0797), has been prepared by the Office of Nuclear Reactor Regulation of the US Nuclear Regulatory Commission (NRC). The facility is located in Somervell County, Texas, approximately 40 miles southwest of Fort Worth, Texas. This supplement reports the status of certain issues that had not been resolved when the Safety Evaluation Report and supplements 1, 2, 3, 4, 6, 12, 21, and 22 to that report were published. This supplement also includes the evaluations for licensing items resolved since Supplement 22 was issued. Supplement 5 has not been issued. Supplements 7, 8, 9, 10, and 11 were limited to the staff evaluation of allegations investigated by the NRC Technical Review Team. Supplement 13 presented the staff's evaluation of the Comanche Peak Response Team (CPRT) Program Plan, which was formulated by the applicant to resolve various construction and design issues raised by sources external to TU Electric. Supplements 14 through 19 presented the staff's evaluation of the CPSES Corrective Action Program: large- and small-bore piping and pipe supports (Supplement 14); cable trays and cable tray hangers (Supplement 15); conduit supports (Supplement 16); mechanical, civil/structural, electrical, instrumentation and controls, and systems portions of the heating, ventilation, and air conditioning (HVAC) system workscopes (Supplement 17); HVAC structural design (Supplement 18); and equipment qualification (Supplement 19). Supplement 20 presented the staff's evaluation of the Comanche Peak Response Team implementation of the CPRT Program

  5. 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.

  6. The effect of acute L-Carnitine supplementation on the blood lactate, glucose, VO2max and power in trained men: a brief report

    Directory of Open Access Journals (Sweden)

    Arazi H

    2013-04-01

    Full Text Available Background: Probably L-Carnitine can induce increasing of Pyruvate dehydrogenase activity, decreasing of lactic acid production and performance improvements due to the reinforcement of long chain fatty acid oxidation and stabilize of Coenzyme A (CoASH to free Coenzyme A (COA. Based on this, the aim of this study was to investigate the effect of acute L-Carnitine supplementation on blood lactate, glucose, VO2max and anaerobic power in trained men.Methods: Sixteen trained men (aged 19-23 volunteers from University of Guilan, facul-ty of Physical Education and Sport Sciences participated as subjects in this investiga-tion. Subjects divided to aerobic (A and anaerobic (An group randomly. In a double blind design, subjects participated in two separated tests by one week. Subjects ingested 3 grams of L-Carnitine supplementation or placebo (maltodextrin 90 minute before aerobic and anaerobic exercise. For aerobic activity used shuttle run 20 meter and for anaerobic activity used RAST test. Blood samples were collected 5 minute prior at rest and 4 minute post tests. Participants were asked in the morning to obtain fasting blood samples and perform tests. A t-test was used to detect differences between supplementa-tion and placebo groups in each exercise.Results: L-Carnitine group ((A 141.25±20.62 and (An 145.38±55.47 significantly had lower lactate concentration than placebo ((A 151.00±20.85 and (An 152.50±28.59 after tests (P≤0.05. L-Carnitine group ((A 136.00±19.74 and (An 115.50±13.64 had significa-ntly higher blood glucose compared to placebo ((A 121.62±15.65 and (An 110.12±12.63 too (P≤0.05. Also, VO2max, mean and maximum anaerobic power in L-Carnitine group were significantly more than ones in placebo (P<0.05.Conclusion: These findings indicate that acute oral supplementation of L-Carnitine can induce fatigue decreasing and improvement of aerobic and anaerobic performance.

  7. Safety Evaluation Report related to the operation of Comanche Peak Steam Electric Station, Units 1 and 2 (Docket Nos. 50-445 and 50-446)

    International Nuclear Information System (INIS)

    1990-01-01

    Supplement 22 to the Safety Evaluation Report related to the operation of the Comanche Peak Steam Electric Station, Units 1 and 2 (NUREG-0797), has been prepared by the Office of Nuclear Reactor Regulation of the US Nuclear Regulatory Commission. The facility is located in Somervell County, Texas, approximately 40 miles southwest of Fort Worth, Texas. This supplement reports the status of certain issues that had not been resolved at the time of publication of the Safety Evaluation Report and Supplements 1, 2, 3, 4, 6, 12, and 21 to that report. This supplement also includes the evaluations for licensing items resolved since Supplement 21 was issued. Supplement 5 has been cancelled. Supplements 7 through 11 were limited to the staff evaluation of allegations investigated by the NRC Technical Review Team. Supplement 13 presented the staff's evaluation of the Comanche Peak Response Team (CPRT) Program Plan, which was formulated by the applicant to resolve various construction and design issues raised by sources external to the applicant. Supplements 14 through 20 presented the staff's evaluation of the applicant's Corrective Action Program and CPRT activities. Items identified in Supplements 7, 8, 9, 10, 11, 13, 14, and 15 through 20 are not included in this supplement, except to the extent that they affect the applicant's Final Safety Analysis Report. 154 refs., 24 figs., 8 tabs

  8. Peak Cardiorespiratory Responses of Patients with Subacute Stroke During Land and Aquatic Treadmill Exercise.

    Science.gov (United States)

    Lee, Yong Ki; Kim, Bo Ryun; Han, Eun Young

    2017-05-01

    The aim of this work was to investigate the cardiorespiratory responses of patients with subacute stroke to exercise stress tests with aquatic and land treadmills. Twenty-one consecutive patients who presented with first-ever subacute stroke in 2013-2015. All subjects underwent symptom-limited incremental exercise testing with aquatic and land treadmills. Land treadmill speed started at 1.5 km/h and increased 0.5 km/h every 1 to 2 minutes until maximal tolerable speed was achieved. Thereafter, the grade was elevated by 2% every 2 minutes. In the aquatic treadmill test, subjects were submerged to the xiphoid in 28°C water. Treadmill speed started at 1.5 km/h and was increased 0.5 km/h every 2 minutes thereafter. Cardiorespiratory responses were recorded with aquatic and land treadmills. Compared to land treadmill exercise, aquatic treadmill exercise achieved significantly better peak VO2 (22.0 vs 20.0; P = 0.02), peak metabolic equivalents (6.3 vs 5.8; P = 0.02), and peak rating of perceived exertion (17.6 vs 18.4, P = 0.01). Heart rate and VO2 correlated significantly during both tests (land treadmill: r = 0.96, P aquatic treadmill: r = 0.99, P Aquatic treadmill exercise elicited significantly better peak cardiorespiratory responses than land treadmill exercise and may be as effective for early intensive aerobic training in subacute stroke patients.

  9. Cardiorespiratory Fitness and Peak Torque Differences between Vegetarian and Omnivore Endurance Athletes: A Cross-Sectional Study.

    Science.gov (United States)

    Lynch, Heidi M; Wharton, Christopher M; Johnston, Carol S

    2016-11-15

    In spite of well-documented health benefits of vegetarian diets, less is known regarding the effects of these diets on athletic performance. In this cross-sectional study, we compared elite vegetarian and omnivore adult endurance athletes for maximal oxygen uptake (VO2 max) and strength. Twenty-seven vegetarian (VEG) and 43 omnivore (OMN) athletes were evaluated using VO2 max testing on the treadmill, and strength assessment using a dynamometer to determine peak torque for leg extensions. Dietary data were assessed using detailed seven-day food logs. Although total protein intake was lower among vegetarians in comparison to omnivores, protein intake as a function of body mass did not differ by group (1.2 ± 0.3 and 1.4 ± 0.5 g/kg body mass for VEG and OMN respectively, p = 0.220). VO2 max differed for females by diet group (53.0 ± 6.9 and 47.1 ± 8.6 mL/kg/min for VEG and OMN respectively, p vegetarian endurance athletes' cardiorespiratory fitness was greater than that for their omnivorous counterparts, but that peak torque did not differ between diet groups. These data suggest that vegetarian diets do not compromise performance outcomes and may facilitate aerobic capacity in athletes.

  10. Fine hierarchy of the V-O bonds by advanced solid state NMR: novel Pb4(VO2)(PO4)3 structure as a textbook case.

    Science.gov (United States)

    Tricot, Grégory; Mentré, Olivier; Cristol, Sylvain; Delevoye, Laurent

    2012-12-17

    We report here a complete structural characterization of a new lead Pb(4)(VO(2))(PO(4))(3) vanadophosphate compound by single crystal X-ray diffraction and (51)V and (31)P solid-state NMR spectroscopy. Although structural data are commonly used for the estimation of bond lengths and further delimitation of the true coordination number (e.g., octahedral: 6 versus 5 + 1 versus 4 + 2), we show here for the first time by solid-state NMR a more accurate appreciation of the V-O bonding scheme in this complex oxide which appears well adapted to the full series of vanado-phosphate materials. The direct characterization of V-O-P bridges through the J-mediated correlation (51)V{(31)P} heteronuclear multiple quantum coherence (J-HMQC) technique allows a contrasted hierarchy of the V-O electronic delocalization and indirectly supports the presence or not of the V-O bond. In the reported lead vanado-phosphate structure, the two vanadium polyhedra that have been assigned to octahedra from a bond length point of view have been finally reclassified as tetra- and penta-coordinated units on the basis of the solid-state NMR results. More generally, we believe that the improved characterization of interatomic bonds in various vanado-phosphate structures by solid-state NMR will contribute to a better understanding of the structure/property relationships in this important class of materials.

  11. Safety Evaluation Report related to the operation of Comanche Peak Steam Electric Station, Units 1 and 2. Docket Nos. 50-445 and 50-446

    International Nuclear Information System (INIS)

    1983-03-01

    Supplement No. 3 to the Safety Evaluation Report (SER) related to the operation of the Comanche Peak Steam electric Station, Units 1 and 2, has been prepared by the Office of Nuclear Reactor Regulation of the US Nuclear Regulatory Commission. the facility is located in Somervell County, Texas. Subject to favorable resolution of the items identified in this supplement, the staff concludes that the facility can be operated by the applicatn without endangering the health and safety of the public. This document provides the NRC staff's evaluation of the outstanding and confirmatory issues that have been resolved since Supplement No. 2 was issued in January 1982, and addresses changes to the SER and its earlier supplements which have resulted from the receipt of additonal information from the applicant during the period of January throught October 1982

  12. 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.

  13. Safety evaluation report related to the operation of Comanche Peak Steam Electric Station, Units 1 and 2 (Docket Nos. 50-445 and 50-446)

    International Nuclear Information System (INIS)

    1988-11-01

    Supplement 18 to the Safety Evaluation Report related to the operation of the Comanche Peak Steam Electric Station (CPSES), Units 1 and 2 (NUREG-0797), has been prepared by the Office of Special Projects of the US Nuclear Regulatory Commission (NRC). The facility is located in Somervell County, Texas, approximately 40 miles southwest of Fort Worth, Texas. This supplement presents the staff's evaluation of the applicant's Corrective Action Program (CAP) related to the structural design of the heating, ventilation, and air conditioning (HVAC) systems. The scope and methodologies for the CAP workscope as summarized in Revision 0 to the HVAC project status report and as detailed in related documents referenced in this evaluation were developed to resolve the technical concerns identified in the HVAC area. The NRC staff concludes that the CAP workscope for the HVAC structural design provides a comprehensive program for resolving the associated technical concerns and its implementation ensures that the structural design of the HVAC systems at CPSES satisfies the applicable requirements of 10 CFR Part 50. 32 refs

  14. Peak-bone-mass development in young adults: effects of study program related levels of occupational and leisure time physical activity and exercise. A prospective 5-year study.

    Science.gov (United States)

    Kemmler, W; Bebenek, M; von Stengel, S; Bauer, J

    2015-02-01

    Young adulthood is characterized by profound life-style changes. This study suggests that reduction of sport or exercise, induced by alteration of the occupational situation, negatively impacts generation/maintenance of peak bone mass. In order to compensate occupational-related reductions of physical activity, workplace exercise programs will be helpful. Only few studies have determined the effect of physical activity or physical exercise on bone mineral density (BMD) in the period of late skeletal maturation, i.e. around peak bone mass. The aim of this article was to determine the long-term effect of different levels of physical activity and exercise directly and indirectly derived by occupation during young adulthood. Sixty-one male and female dental students (DES) and 53 male and female sport students (SPS) 21±2 years old were accompanied over the course (4.8±0.5 years) of their study program. BMD at the lumbar spine (LS), hip, and whole body (WB) were determined using dual-energy X-ray absorptiometry. Parameters of physical activity increased non-significantly in both groups with no relevant differences between the groups. Indices of exercise, however, increased significantly in the SPS group while a significant decrease was assessed for the DES group. Independent of gender, BMD of the SPS increased significantly (p≤0.007) at all skeletal sites (LS, 2.4±3.9%; hip, 1.6±3.5%; WB, 1.8±2.8%) while BMD of the DES remained unchanged at LS (-0.6±4.4%, p=0.432) and WB (0.5±1.9%, p=0.092) but decreased significantly at the hip (-1.9±4.3%, p=0.010). BMD-changes at LS, hip, and WB differ significantly between SPS and DES (p≤0.017). Results remained unchanged after adjusting for baseline BMD-values that differed (p=0.030 to p=0.082) in favor of the SPS group. Changes of exercise levels directly or indirectly caused by occupational factors during young adulthood significantly affected generation and/or maintenance of peak bone mass. Compensatory exercise is

  15. Safety evaluation report related to the operation of Comanche Peak Steam Electric Station, Units 1 and 2 (Docket Nos. 50-445 and 50-446)

    International Nuclear Information System (INIS)

    1990-04-01

    Supplement 24 to the Safety Evaluation Report related to the operation of the Comanche Peak Steam Electric Station (CPSES), Units 1 and 2 (NUREG-0797), has been prepared by the Office of Nuclear Reactor Regulation of the US Nuclear Regulatory Commission (NRC). The facility is located in Somervell County, Texas, approximately 40 miles southwest of Fort Worth, Texas. This supplement reports the status of certain issues that had not been resolved when the Safety Evaluation Report and Supplements 1, 2, 3, 4, 6, 12, 21, 22, and 23 to that report were published. This supplement also includes the evaluations for licensing items resolved since Supplement 23 was issued. Supplement 5 has not been issued. Supplements 7, 8, 9, 10, and 11 were limited to the staff evaluation of allegations investigated by the NRC Technical Review Team. Supplement 13 represented the staff's evaluation of the Comanche Peak Response Team (CPRT) Program Plan, which was formulated by the applicant to resolve various construction and design issues raised by sources external to TU Electric. Supplements 14 through 19 presented the staff's evaluation of the CPSES Corrective Action Program: large- and small-bore piping and pipe supports (Supplement 14); cable trays and cable tray hangers (Supplement 15); conduit supports (Supplement 16); mechanical, civil/structural, electrical, instrumentation and controls, and systems portions of the heating, ventilation, and air conditioning (HVAC) system workscopes (Supplement 17); HVAC structural design (Supplement 18); and equipment qualification (Supplement 19). Supplement 20 presented the staff's evaluation of the CPRT implementation of its Program Plan and the issue-specific action plans, as well as the CPRT's investigations to determine the adequacy of various types of programs and hardware at CPSES

  16. Perceptions and behaviors related to hand hygiene for the prevention of H1N1 influenza transmission among Korean university students during the peak pandemic period

    Directory of Open Access Journals (Sweden)

    Kim Seon-Ung

    2010-07-01

    Full Text Available Abstract Background This study was performed to better assess the perceptions, motivating factors, and behaviors associated with the use of hand washing to prevent H1N1 influenza transmission during the peak pandemic period in Korea. Methods A cross-sectional survey questionnaire was completed by 942 students at a university campus in Suwon, Korea, between December 1 and 8, 2009. The survey included questions regarding individual perceptions, motivating factors, and behaviors associated with hand washing for the prevention of H1N1 influenza transmission. Results Compared to one year prior, 30.3% of participants reported increasing their hand washing frequency. Female students were more likely to practice more frequent hand washing. Women also perceived the effectiveness of hand washing to be lower, and illness severity and personal susceptibility to H1N1 infection to be higher. Study participants who were female (OR: 1.79-3.90 who perceived of hand washing to be effective (OR: 1.34-12.15 and illness severity to be greater (OR: 1.00-3.12 washed their hands more frequently. Conclusions Korean students increased their frequency of hand hygiene practices during the pandemic, with significant gender differences existing in the attitudes and behaviors related to the use of hand hygiene as a means of disease prevention. Here, the factors that affected hand washing behavior were similar to those identified at the beginning of the H1N1 or SARS pandemics, suggesting that public education campaigns regarding hand hygiene are effective in altering individual hand hygiene habits during the peak periods of influenza transmission.

  17. Patellar tendon properties distinguish elite from non-elite soccer players and are related to peak horizontal but not vertical power.

    Science.gov (United States)

    Murtagh, Conall F; Stubbs, Michael; Vanrenterghem, Jos; O'Boyle, Andrew; Morgans, Ryland; Drust, Barry; Erskine, Robert M

    2018-06-02

    To investigate potential differences in patellar tendon properties between elite and non-elite soccer players, and to establish whether tendon properties were related to power assessed during unilateral jumps performed in different directions. Elite (n = 16; age 18.1 ± 1.0 years) and non-elite (n = 13; age 22.3 ± 2.7 years) soccer players performed vertical, horizontal-forward and medial unilateral countermovement jumps (CMJs) on a force plate. Patellar tendon (PT) cross-sectional area, elongation, strain, stiffness, and Young's modulus (measured at the highest common force interval) were assessed with ultrasonography and isokinetic dynamometry. Elite demonstrated greater PT elongation (6.83 ± 1.87 vs. 4.92 ± 1.88 mm, P = 0.011) and strain (11.73 ± 3.25 vs. 8.38 ± 3.06%, P = 0.009) than non-elite soccer players. Projectile range and peak horizontal power during horizontal-forward CMJ correlated positively with tendon elongation (r = 0.657 and 0.693, P < 0.001) but inversely with Young's modulus (r = - 0.376 and - 0.402; P = 0.044 and 0.031). Peak medial power during medial CMJ correlated positively with tendon elongation (r = 0.658, P < 0.001) but inversely with tendon stiffness (r = - 0.368, P = 0.050). Not only does a more compliant patellar tendon appear to be an indicator of elite soccer playing status but it may also facilitate unilateral horizontal-forward and medial, but not vertical CMJ performance. These findings should be considered when prescribing talent selection and development protocols related to direction-specific power in elite soccer players.

  18. CGRO/BATSE Data Support the New Paradigm For GRB Prompt Emission and the New L-i(nTh)-E-peak,i(nTh,rest) Relation

    Science.gov (United States)

    Guiriec, S.; Gonzalez, M.M.; Sacahui, J.R.; Kouveliotou, C.; Gehrels, N.; McEnery, J.

    2016-01-01

    The paradigm for gamma-ray burst (GRB) prompt emission is changing. Since early in the Compton Gamma RayObservatory (CGRO) era, the empirical Band function has been considered a good description of the keV-MeV-gamma-ray prompt emission spectra despite the fact that its shape was very often inconsistent with the theoretical predictions, especially those expected in pure synchrotron emission scenarios. We have recently established a new observational model analyzing data of the NASA Fermi Gamma-ray Space Telescope. In this model, GRB prompt emission would be a combination of three main emission components: (i) a thermal-like component that we have interpreted so far as emission from the jet photosphere, (ii) a non-thermal component that we have interpreted so far as either synchrotron radiation from the propagating and accelerated charged particles within the jet or reprocessed jet photospheric emission, and (iii) an additional non-thermal (cutoff) power law (PL) extending from low to high energies in gamma-rays and most likely of inverse Compton origin. In this article we reanalyze some of the bright GRBs, namely GRBs 941017, 970111, and 990123, observed with the Burst And Transient Source Experiment (BATSE) on board CGRO with the new model. We conclude that BATSE data for these three GRBs are fully consistent with the recent results obtained with Fermi: some bright BATSE GRBs exhibit three separate components during the prompt phase with similar spectral parameters as those reported from Fermi data. In addition, the analysis of the BATSE GRBs with the new prompt emission model results in a relation between the time-resolved energy flux of the non-thermal component, F(in)(Th), and its corresponding nuFnu spectral peak energy,Epeak,inTh (i.e., FinThEpeak,inTh ), which has a similar index when fitted to a PL as the one initially derived from Fermi data. For GRBs with known redshifts (z) this results in a possible universal relation between the luminosity of the non

  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. Characterization of a multilayer ionization chamber prototype for fast verification of relative depth ionization curves and spread-out-Bragg-peaks in light ion beam therapy.

    Science.gov (United States)

    Mirandola, Alfredo; Magro, Giuseppe; Lavagno, Marco; Mairani, Andrea; Molinelli, Silvia; Russo, Stefania; Mastella, Edoardo; Vai, Alessandro; Maestri, Davide; La Rosa, Vanessa; Ciocca, Mario

    2018-05-01

    To dosimetrically characterize a multilayer ionization chamber (MLIC) prototype for quality assurance (QA) of pristine integral ionization curves (ICs) and spread-out-Bragg-peaks (SOBPs) for scanning light ion beams. QUBE (De.Tec.Tor., Torino, Italy) is a modular detector designed for QA in particle therapy (PT). Its main module is a MLIC detector, able to evaluate particle beam relative depth ionization distributions at different beam energies and modulations. The charge collecting electrodes are made of aluminum, for a nominal water equivalent thickness (WET) of ~75 mm. The detector prototype was calibrated by acquiring the signals in the initial plateau region of a pristine BP and in terms of WET. Successively, it was characterized in terms of repeatability response, linearity, short-term stability and dose rate dependence. Beam-induced measurements of activation in terms of ambient dose equivalent rate were also performed. To increase the detector coarse native spatial resolution (~2.3 mm), several consecutive acquisitions with a set of certified 0.175-mm-thick PMMA sheets (Goodfellow, Cambridge Limited, UK), placed in front of the QUBE mylar entrance window, were performed. The ICs/SOBPs were achieved as the result of the sum of the set of measurements, made up of a one-by-one PMMA layer acquisition. The newly obtained detector spatial resolution allowed the experimental measurements to be properly comparable against the reference curves acquired in water with the PTW Peakfinder. Furthermore, QUBE detector was modeled in the FLUKA Monte Carlo (MC) code following the technical design details and ICs/SOBPs were calculated. Measurements showed a high repeatability: mean relative standard deviation within ±0.5% for all channels and both particle types. Moreover, the detector response was linear with dose (R 2  > 0.998) and independent on the dose rate. The mean deviation over the channel-by-channel readout respect to the reference beam flux (100%) was equal

  1. Lung volumes related to physical activity, physical fitness, aerobic capacity and body mass index in students

    Directory of Open Access Journals (Sweden)

    Mihailova A.

    2016-01-01

    Reduced lung volumes were associated with lower aerobic fitness, lower physical fitness and lower amount of weekly physical activity. Healthier body mass index was associated with higher aerobic fitness (relative VO2max in both female and male.

  2. Validation of sleep-2-Peak: A smartphone application that can detect fatigue-related changes in reaction times during sleep deprivation.

    Science.gov (United States)

    Brunet, Jean-François; Dagenais, Dominique; Therrien, Marc; Gartenberg, Daniel; Forest, Geneviève

    2017-08-01

    Despite its high sensitivity and validity in the context of sleep loss, the Psychomotor Vigilance Test (PVT) could be improved. The aim of the present study was to validate a new smartphone PVT-type application called sleep-2-Peak (s2P) by determining its ability to assess fatigue-related changes in alertness in a context of extended wakefulness. Short 3-min versions of s2P and of the classic PVT were administered at every even hour during a 35-h total sleep deprivation protocol. In addition, subjective measures of sleepiness were collected. The outcomes on these tests were then compared using Pearson product-moment correlations, t tests, and repeated measures within-groups analyses of variance. The results showed that both tests significantly correlated on all outcome variables, that both significantly distinguished between the alert and sleepy states in the same individual, and that both varied similarly through the sleep deprivation protocol as sleep loss accumulated. All outcome variables on both tests also correlated significantly with the subjective measures of sleepiness. These results suggest that a 3-min version of s2P is a valid tool for differentiating alert from sleepy states and is as sensitive as the PVT for tracking fatigue-related changes during extended wakefulness and sleep loss. Unlike the PVT, s2P does not provide feedback to subjects on each trial. We discuss how this feature of s2P raises the possibility that the performance results measured by s2P could be less impacted by motivational confounds, giving this tool added value in particular clinical and/or research settings.

  3. Problematic issues of air protection during thermal processes related to the energetic uses of sewage sludge and other waste. Case study: Co-combustion in peaking power plant.

    Science.gov (United States)

    Hroncová, Emília; Ladomerský, Juraj; Musil, Juraj

    2018-03-01

    Currently, it is necessary to deal with issues related to the emissions as there is a constantly increasing interest in combusting sludge from sewage treatment plants in the boilers for wood. An analysis of the energetic importance of the combustion of sewage sludge has already been carried out, but the effects of various treatments of the sludge are not always clear, e.g. composting and subsequent combustion to the air pollution. Investments in other thermal processes of energetic utilisation of sewage sludge and organic waste are not always successfully implemented. The objective of this paper is to point out some problematic cases for acceptance of thermal processes related to energetic use of waste in terms of the air protection. The other aim is to mention the experience with solutions of such issues in Slovakia. There are mentioned first results of the operational validation experiments during the energy generation in circulating fluidized bed boiler in peaking power plant (Power 110MW) with the addition of the so-called alternative fuel based on wood and sewage sludge to the main fuel - black coal (anthracite). And there has already been achieved the highest share of 12.4%w. (dry matter) of sewage sludge in form of compost in blend with black coal, which is technologically viable. Moreover analyzed the problems of the authorization and operation of the co-combustion of sewage sludge and of combustion of products of various kinds of pyrolysis waste - pyrolysis gas and pyrolysis oil are analyzed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Thermodynamic studies at the low-dimensional spin systems HP-(VO)2P2O7, SrCu2(BO3)2, and azurite

    International Nuclear Information System (INIS)

    Bruehl, Andreas

    2007-01-01

    The present thesis deals with the low-temperature properties of three low-dimensional spin systems. The main experimental topic lies on measurements on the thermal expansion and on the specific heat, which were performed with a high-resolution capacitative dilatometer respectively an AC calorimeter facility. Because the so-called magnetic Grueneisen parameters, which describe the strength of the coupling of the magnetic partial system to the lattice, are throughout very large, especially the thermal-expansion measurements yield valuable information on the understanding of the treated systems. The central result of this thesis represent measurements on the high-pressure phase of (VO) 2 P 2 O 7 , briefly PP-VOPO. This system consists of alternating spin chains, whereby both exchange constants have similar values, i. e. only a weak alternation is present. In the thermal expansion an anomaly especially pronounced in chain direction at about 13 K. From the Grueneisen parameters determined by application of this model it can be concluded that the pronounced low-temperature anomaly in HP-VOPO is partly caused by the strong deformation dependence of the smaller of the two exchange constants, but partly also on the neighbourhood to a quantum critical point. The two-dimensional dimer system SrCu 2 (BO 3 ) 2 has gotten fame by the localization of the triplet excitations and the magnetization plateaus at certain fractions of the saturation magnetization conditioned by this. In the thermal expansion a distinct anomaly at the same temperature (T=8 K) is observed, as it also occurs in the specific heat. Finally measurements at the natural mineral azurite are presented, in which the spin are arranged in so-called diamond chains. In the magnetic susceptibility, the specific heat, and the thermal expansion a remarkable double structure occurs. Also the Λ-shaped antiferromagnetic order transition was studied and the phase diagram, consisting of paramagnetic, antiferromagnetic, and

  5. Relative Biological Effectiveness Variation Along Monoenergetic and Modulated Bragg Peaks of a 62-MeV Therapeutic Proton Beam: A Preclinical Assessment

    International Nuclear Information System (INIS)

    Chaudhary, Pankaj; Marshall, Thomas I.; Perozziello, Francesca M.; Manti, Lorenzo; Currell, Frederick J.; Hanton, Fiona; McMahon, Stephen J.; Kavanagh, Joy N.; Cirrone, Giuseppe Antonio Pablo; Romano, Francesco; Prise, Kevin M.; Schettino, Giuseppe

    2014-01-01

    Purpose: The biological optimization of proton therapy can be achieved only through a detailed evaluation of relative biological effectiveness (RBE) variations along the full range of the Bragg curve. The clinically used RBE value of 1.1 represents a broad average, which disregards the steep rise of linear energy transfer (LET) at the distal end of the spread-out Bragg peak (SOBP). With particular attention to the key endpoint of cell survival, our work presents a comparative investigation of cell killing RBE variations along monoenergetic (pristine) and modulated (SOBP) beams using human normal and radioresistant cells with the aim to investigate the RBE dependence on LET and intrinsic radiosensitvity. Methods and Materials: Human fibroblasts (AG01522) and glioma (U87) cells were irradiated at 6 depth positions along pristine and modulated 62-MeV proton beams at the INFN-LNS (Catania, Italy). Cell killing RBE variations were measured using standard clonogenic assays and were further validated using Monte Carlo simulations and the local effect model (LEM). Results: We observed significant cell killing RBE variations along the proton beam path, particularly in the distal region showing strong dose dependence. Experimental RBE values were in excellent agreement with the LEM predicted values, indicating dose-averaged LET as a suitable predictor of proton biological effectiveness. Data were also used to validate a parameterized RBE model. Conclusions: The predicted biological dose delivered to a tumor region, based on the variable RBE inferred from the data, varies significantly with respect to the clinically used constant RBE of 1.1. The significant RBE increase at the distal end suggests also a potential to enhance optimization of treatment modalities such as LET painting of hypoxic tumors. The study highlights the limitation of adoption of a constant RBE for proton therapy and suggests approaches for fast implementation of RBE models in treatment planning

  6. Peak Experience Project

    Science.gov (United States)

    Scott, Daniel G.; Evans, Jessica

    2010-01-01

    This paper emerges from the continued analysis of data collected in a series of international studies concerning Childhood Peak Experiences (CPEs) based on developments in understanding peak experiences in Maslow's hierarchy of needs initiated by Dr Edward Hoffman. Bridging from the series of studies, Canadian researchers explore collected…

  7. Cadetes of the Academia do Polícia Militar do Estado do Rio de Janeiro Correlación entre VO2 max, gordura relativa y perfil lipídico, en cadetes de la Academia de Policía Militar del Estado de Río de Janeiro

    Directory of Open Access Journals (Sweden)

    E. H. M. Dantas

    2010-09-01

    Full Text Available The objective of the present study was to verify the correlation level among the max, the relative fat and the profile lipídico of 51 Cadets (Age = 23.63 3.58 years; Weight = 74.13 ± 10.46 kg; Height = 1.76 ± 0.06 m; IMC = 23.99 2.76 kg/m2, of the masculine gender, of the Academy of the Military police of the State of Rio de Janeiro, of the year of 2007. The subjects were active and participants of the military physical training (TFM accomplished five times a week, with duration of 60 minutes for session. They were appraised: the max for ergoespirometria (I record of progressive effort, with constant inclination of 3% and initial speed of 4,0km/h, the relative fat (% G - I record of three cutaneous folds and the profile lipídico, through the method Enzymatic Calorimétrico in the variables: total cholesterol (CT, triglicérides (TG, lipoproteína of density high-cholesterol (HDL-C and lipoproteína of density low-cholesterol (LDL-C. The test of correlation of Spearman presented correlation significant between max and TG (r = -0,289; p = 0,04,  max and HDL-C (r = 0,277; p = 0,049,% G and TG (r = 0,296; p = 0,035,% G and HDL-C (r = 0,338; p = 0,015. Like this, these discoveries point a discreet relationship between the profile lipídico and the maximum consumption of oxygen corroborating the need to consider other factors as the feeding and the intensity of the exercises in the investigation of this relationship.

    Key Words: training,  VO2 max, relative fat, lipidic profile.

     

    El objetivo del presente estudio es establecer el nivel de correlación entre el  VO2 max, la grasa relativa y el perfil lipídico de 51 cadetes varones (Edad = 23.63 ± 3.58 años; Peso = 74.13 ± 10.46 Kg.; Talla = 1.76  ± 0.06 m; IMC = 23.99 ± 2.76 Kg. /m2 de la Academia de la Policía Militar del Estado de Río de Janeiro, del año de 2007. Los sujetos son f

  8. Cinética do consumo de oxigênio e tempo limite na vvo2max: comparação entre homens e mulheres Oxygen uptake kinetics and threshold time at the vVO2max: tomparison between men and women

    Directory of Open Access Journals (Sweden)

    Paulo Henrique Silva Marques de Azevedo

    2010-08-01

    Full Text Available Foi investigada a influência do gênero no tempo limite (Tlim e na cinética do VO2 durante corrida na velocidade associada ao VO2max (vVO2max em nove homens e nove mulheres, todos adultos, jovens e sedentários, com idades entre 20 e 30 anos. Homens e mulheres realizaram dois testes em esteira rolante, sendo um teste incremental para determinar VO2max (42,66 ± 4,50 vs. 32,92 ± 6,03mL.kg-1.min-1 e vVO2max (13.2 ± 1.5 vs. 10,3 ± 2,0km.h-1, respectivamente. Um segundo teste com carga constante na vVO2max até a exaustão. O Tlim e a cinética do VO2 foram determinados. Não houve diferença significante entre homens e mulheres para constante de tempo (τ (35,76 ± 21,03 vs. 36,5 ± 6,21s, respectivamente; P = 0,29; Tlim (308 ± 84,3 vs. 282,11 ± 57,19s, respectivamente; P = 0,68, tempo para atingir o VO2max (TAVO2max (164,48 ± 96,73 vs. 167,88 ± 28,59s, respectivamente; P = 0,29, tempo para atingir o VO2max em percentual do Tlim (%Tlim (50,24 ± 16,93 vs. 62,63 ± 16,60%, respectivamente; P = 0,19, tempo mantido no VO2max (TMVO2max (144,08 ± 42,55 vs. 114,23 ± 76,96s, respectivamente; P = 0,13. Estes resultados sugerem que a cinética do VO2 e o Tlim são similares entre homens e mulheres sedentários na vVO2max.The aim of this study was to investigate the influence of gender on Tthre and VO2 response during running exercise performed at vVO2max. Therefore, eighteen untrained individuals (9 male and 9 female with normal weight and aged between 20 - 30 years (VO2max = 42.66 ± 4.50 vs 32.92 ± 6.03 mL.kg-1.min-1 and vVO2max = 13.2 ± 1.5 vs 10.3 ± 2.0 km.h-1, for male and female, respectively were assessed. Subjects performed two exercise tests on treadmill. First one was an incremental test to determine VO2max, velocity at VO2max (vVO2max and second test was performed at steady velocity - vVO2max - until exhaustion. The threshold time (Tthre and VO2 kinetics response was determined. No significant differences were observed between men

  9. 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.

  10. 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...

  11. Lower extremity injury in female basketball players is related to a large difference in peak eversion torque between barefoot and shod conditions

    Directory of Open Access Journals (Sweden)

    Jennifer M. Yentes

    2014-09-01

    Conclusion: It is possible that a large discrepancy between strength in barefoot and shod conditions can predispose an athlete to injury. Narrowing the difference in peak eversion torque between barefoot and shod could decrease propensity to injury. Future work should investigate the effect of restoration of muscular strength during barefoot and shod exercise on injury rates.

  12. A high-resolution peak fractionation approach for streamlined screening of nuclear-factor-E2-related factor-2 activators in Salvia miltiorrhiza.

    Science.gov (United States)

    Zhang, Hui; Luo, Li-Ping; Song, Hui-Peng; Hao, Hai-Ping; Zhou, Ping; Qi, Lian-Wen; Li, Ping; Chen, Jun

    2014-01-24

    Generation of a high-purity fraction library for efficiently screening active compounds from natural products is challenging because of their chemical diversity and complex matrices. In this work, a strategy combining high-resolution peak fractionation (HRPF) with a cell-based assay was proposed for target screening of bioactive constituents from natural products. In this approach, peak fractionation was conducted under chromatographic conditions optimized for high-resolution separation of the natural product extract. The HRPF approach was automatically performed according to the predefinition of certain peaks based on their retention times from a reference chromatographic profile. The corresponding HRPF database was collected with a parallel mass spectrometer to ensure purity and characterize the structures of compounds in the various fractions. Using this approach, a set of 75 peak fractions on the microgram scale was generated from 4mg of the extract of Salvia miltiorrhiza. After screening by an ARE-luciferase reporter gene assay, 20 diterpene quinones were selected and identified, and 16 of these compounds were reported to possess novel Nrf2 activation activity. Compared with conventional fixed-time interval fractionation, the HRPF approach could significantly improve the efficiency of bioactive compound discovery and facilitate the uncovering of minor active components. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Peak-interviewet

    DEFF Research Database (Denmark)

    Raalskov, Jesper; Warming-Rasmussen, Bent

    Peak-interviewet er en særlig effektiv metode til at gøre ubevidste menneskelige ressourcer bevidste. Fokuspersonen (den interviewede) interviewes om en selvvalgt, personlig succesoplevelse. Terapeuten/coachen (intervieweren) spørger ind til processen, som ledte hen til denne succes. Herved afdæk...... fokuspersonen ønsker at tage op (nye mål eller nye processer). Nærværende workingpaper beskriver, hvad der menes med et peak-interview, peakinterviwets teoretiske fundament samt metodikken til at foretage et tillidsfuldt og effektiv peak-interview....

  14. Peak power ratio generator

    Science.gov (United States)

    Moyer, R.D.

    A peak power ratio generator is described for measuring, in combination with a conventional power meter, the peak power level of extremely narrow pulses in the gigahertz radio frequency bands. The present invention in a preferred embodiment utilizes a tunnel diode and a back diode combination in a detector circuit as the only high speed elements. The high speed tunnel diode provides a bistable signal and serves as a memory device of the input pulses for the remaining, slower components. A hybrid digital and analog loop maintains the peak power level of a reference channel at a known amount. Thus, by measuring the average power levels of the reference signal and the source signal, the peak power level of the source signal can be determined.

  15. Relative thermoluminescent efficiencies proton/gamma and helium/gamma of peaks of high temperature in TLD-100 dosemeters; Eficiencias termoluminiscentes relativas proton/gamma y helio/gamma de picos de alta temperatura en dosimetros TLD-100

    Energy Technology Data Exchange (ETDEWEB)

    Flores M, E. [UNAM, Facultad de Ciencias, 04510 Mexico D.F. (Mexico)

    2007-07-01

    The increase of the applications of ion beams in radiotherapy treatments has generated interest in the study of the thermoluminescent materials (TL) that allow to determine the applied doses. A way to quantify the TL response from these materials to ions is by means of the relative thermoluminescent efficiency. In the group of Thermoluminescent dosimetry of the Institute of Physics of the UNAM (IFUNAM) the thermoluminescent response of the TLD-100 dosemeters has been studied, which present a glow curve characteristic with several peaks that correspond to traps and luminescent centers in the material. The stable peaks know each other as 4, 5, 6a, 6b, 7, 8, 9 and 10. The efficiencies should be measured using the response so much to the radiation of interest (in this case protons and helium ions) as the response to gamma radiation. In previous works with ions of low energy taken place in the Pelletron accelerator of the IFUNAM was only measured the TL efficiency for the peak 5 and the total signal. It had not been possible to measure the efficiency of the peaks of high temperature (6a-10) because, for the gamma radiation, the peaks of high temperature show very small signals; however, recently Massillon carries out measures of efficiency TL of peaks of high temperature for ions of intermediate energy using a protocol special of reading and of deconvolution that allows to measure the signals coming from the peaks of high temperature. In this work is implemented this same protocol to complete the study of TL efficiencies at low energy of protons and helium and to determine if the values of efficiency depend on the used reading protocol. For it is reported it measures of the relative efficiency of the peaks of high temperature from the TLD-100 exposed to protons of 1.5 MeV and nuclei of helium of 3 and 7.5 MeV. (Author)

  16. Cardiorespiratory Fitness and Peak Torque Differences between Vegetarian and Omnivore Endurance Athletes: A Cross-Sectional Study

    Directory of Open Access Journals (Sweden)

    Heidi M. Lynch

    2016-11-01

    Full Text Available In spite of well-documented health benefits of vegetarian diets, less is known regarding the effects of these diets on athletic performance. In this cross-sectional study, we compared elite vegetarian and omnivore adult endurance athletes for maximal oxygen uptake (VO2 max and strength. Twenty-seven vegetarian (VEG and 43 omnivore (OMN athletes were evaluated using VO2 max testing on the treadmill, and strength assessment using a dynamometer to determine peak torque for leg extensions. Dietary data were assessed using detailed seven-day food logs. Although total protein intake was lower among vegetarians in comparison to omnivores, protein intake as a function of body mass did not differ by group (1.2 ± 0.3 and 1.4 ± 0.5 g/kg body mass for VEG and OMN respectively, p = 0.220. VO2 max differed for females by diet group (53.0 ± 6.9 and 47.1 ± 8.6 mL/kg/min for VEG and OMN respectively, p < 0.05 but not for males (62.6 ± 15.4 and 55.7 ± 8.4 mL/kg/min respectively. Peak torque did not differ significantly between diet groups. Results from this study indicate that vegetarian endurance athletes’ cardiorespiratory fitness was greater than that for their omnivorous counterparts, but that peak torque did not differ between diet groups. These data suggest that vegetarian diets do not compromise performance outcomes and may facilitate aerobic capacity in athletes.

  17. Peak Oil, Peak Coal and Climate Change

    Science.gov (United States)

    Murray, J. W.

    2009-05-01

    Research on future climate change is driven by the family of scenarios developed for the IPCC assessment reports. These scenarios create projections of future energy demand using different story lines consisting of government policies, population projections, and economic models. None of these scenarios consider resources to be limiting. In many of these scenarios oil production is still increasing to 2100. Resource limitation (in a geological sense) is a real possibility that needs more serious consideration. The concept of 'Peak Oil' has been discussed since M. King Hubbert proposed in 1956 that US oil production would peak in 1970. His prediction was accurate. This concept is about production rate not reserves. For many oil producing countries (and all OPEC countries) reserves are closely guarded state secrets and appear to be overstated. Claims that the reserves are 'proven' cannot be independently verified. Hubbert's Linearization Model can be used to predict when half the ultimate oil will be produced and what the ultimate total cumulative production (Qt) will be. US oil production can be used as an example. This conceptual model shows that 90% of the ultimate US oil production (Qt = 225 billion barrels) will have occurred by 2011. This approach can then be used to suggest that total global production will be about 2200 billion barrels and that the half way point will be reached by about 2010. This amount is about 5 to 7 times less than assumed by the IPCC scenarios. The decline of Non-OPEC oil production appears to have started in 2004. Of the OPEC countries, only Saudi Arabia may have spare capacity, but even that is uncertain, because of lack of data transparency. The concept of 'Peak Coal' is more controversial, but even the US National Academy Report in 2007 concluded only a small fraction of previously estimated reserves in the US are actually minable reserves and that US reserves should be reassessed using modern methods. British coal production can be

  18. Final environmental statement related to the operation of Comanche Peak Steam Electric Station, Units 1 and 2: (Docket Nos. 50-445 and 50-446)

    International Nuclear Information System (INIS)

    1981-09-01

    The proposed action is the issuance of operating licenses to the Texas Utilities Generating Company for the startup and operation of Units 1 and 2 of the Comanche Peak Steam Electric Station located on Squaw Creek Reservoir in Somervell County, Texas, about 7 km north-northeast of Glen Rose, Texas, and about 65 km southwest of Fort Worth in north-central Texas. The information in this environmental statement represents the second assessment of the environmental impact associated with the Comanche Peak Steam Electric Station pursuant to the guidelines of the National Environmental Policy Act of 1969 (NEPA) and 10 CFR Part 51 of the Commission's Regulations. After receiving an application to construct this station, the staff carried out a review of impact that would occur during its construction and operation. This evaluation was issued as a Final Environmental Statement -- Construction Phase. After this environmental review, a safety review, an evaluation by the Advisory Committee on Reactor Safeguards, and public hearings in Glen Rose, Texas, the US Atomic Energy Commission (now US Nuclear Regulatory Commission) issued construction permits for the construction of Units 1 and 2 of the Comanche Peak Steam Electric Station. 16 figs., 34 tabs

  19. EFECTO DE UN PLAN DE ENTRENAMIENTO FÍSICO EN EL CONSUMO MÁXIMO DE OXÍGENO (VO2MÁX Y EL PESO EN PACIENTES HIPERTENSOS ADULTOS MAYORES ADSCRITOS A LA IPS CAJASAN (BUCARAMANGA

    Directory of Open Access Journals (Sweden)

    Jorge Luis Pérez Sierra

    2014-11-01

    Full Text Available El ejercicio físico adquiere cada vez más importancia en el tratamiento de los pacientes con hipertensión arterial, sobrepeso y obesidad. Desde hace más de cinco décadas se sabe que el ejercicio físico tiene efectos favorables en el tratamiento de la hipertensión arterial y otros factores de riesgo, es coadyuvante en el tratamiento de las enfermedades cardiovasculares y favorece el consumo máximo de oxígeno (VO2máx. El objetivo de este trabajo fue determinar el efecto de un plan de entrenamiento físico sobre el VO2máx y el peso en adultos mayores hipertensos adscritos a la IPS Cajasan Bucaramanga. Es una investigación cuasiexperimental, se tomaron cuarenta pacientes entre 60 y 75 años, en dos grupos iguales, uno con entrenamiento aeróbico, fuerza y flexibilidad (intervención, el otro, caminata diaria, (control, con duración de doce semanas. Se tomó pretest y postest con prueba de esfuerzo, peso, índice de masa corporal, perímetro de cintura. Se compararon los resultados. En el grupo intervención, el VO2máx aumentó 27%, el peso disminuyó 2,2 %, el perímetro de cintura bajó el 2%. En el grupo control no hubo cambios significativos.

  20. Peak regulation right

    International Nuclear Information System (INIS)

    Gao, Z. |; Ren, Z.; Li, Z.; Zhu, R.

    2005-01-01

    A peak regulation right concept and corresponding transaction mechanism for an electricity market was presented. The market was based on a power pool and independent system operator (ISO) model. Peak regulation right (PRR) was defined as a downward regulation capacity purchase option which allowed PRR owners to buy certain quantities of peak regulation capacity (PRC) at a specific price during a specified period from suppliers. The PRR owner also had the right to decide whether or not they would buy PRC from suppliers. It was the power pool's responsibility to provide competitive and fair peak regulation trading markets to participants. The introduction of PRR allowed for unit capacity regulation. The PRR and PRC were rated by the supplier, and transactions proceeded through a bidding process. PRR suppliers obtained profits by selling PRR and PRC, and obtained downward regulation fees regardless of whether purchases are made. It was concluded that the peak regulation mechanism reduced the total cost of the generating system and increased the social surplus. 6 refs., 1 tab., 3 figs

  1. Power peaking nuclear reliability factors

    International Nuclear Information System (INIS)

    Hassan, H.A.; Pegram, J.W.; Mays, C.W.; Romano, J.J.; Woods, J.J.; Warren, H.D.

    1977-11-01

    The Calculational Nuclear Reliability Factor (CNRF) assigned to the limiting power density calculated in reactor design has been determined. The CNRF is presented as a function of the relative power density of the fuel assembly and its radial local. In addition, the Measurement Nuclear Reliability Factor (MNRF) for the measured peak hot pellet power in the core has been evaluated. This MNRF is also presented as a function of the relative power density and radial local within the fuel assembly

  2. 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

  3. Make peak flow a habit

    Science.gov (United States)

    Asthma - make peak flow a habit; Reactive airway disease - peak flow; Bronchial asthma - peak flow ... 2014:chap 55. National Asthma Education and Prevention Program website. How to use a peak flow meter. ...

  4. Efeito do tempo de intervalo da amostra ventilatória na variabilidade do consumo máximo de oxigênio (VO2 máx em jogadores de futebol profissional

    Directory of Open Access Journals (Sweden)

    Paulo Roberto Santos Silva

    1999-04-01

    Full Text Available O propósito deste estudo foi verificar, em futebolistas profissionais, o impacto de sete intervalos de tempo sobre a variável fisiológica consumo máximo de oxigênio (VO2 máx. Dezoito jogadores de futebol com média de idade de 24 ± 4 anos (18-31, peso de 72,5 ± 5,9kg (62-83 e estatura de 176,5 ± 7,0cm (164-188 foram submetidos a teste ergométrico máximo em esteira rolante, utilizando-se protocolo escalonado contínuo. A resposta de freqüência cardíaca (FC foi registrada por meio de um eletrocardiógrafo computadorizado de 12 derivações simultâneas. A ventilação pulmonar (V E, o consumo de oxigênio (VO2, a produção de dióxido de carbono (VCO2 e a razão de troca respiratória (RER foram calculadas a partir de valores medidos por um sistema espirométrico computadorizado. Os resultados deste estudo demonstraram que houve variabilidade significante do VO2 máx (p < 0,05 somente quando se comparou a resposta instantânea respiração-a-respiração (breath-by-breath em relação aos outros intervalos de tempos analisados (10, 20, 30, 40, 50 e 60 segundos, respectivamente. Concluindo, durante o exercício de intensidade progressiva, observou-se que o aumento do VO2 foi proporcional à diminuição do intervalo de tempo da coleta ventilatória. O tempo de intervalo maior subestimou esse aumento. Assim, sugere-se que o avaliador utilize intervalos médios na faixa de tempo entre 10 e 60 segundos, pois não foi verificada diferença estatística significante entre esses intervalos.

  5. Automated asteroseismic peak detections

    DEFF Research Database (Denmark)

    de Montellano, Andres Garcia Saravia Ortiz; Hekker, S.; Themessl, N.

    2018-01-01

    Space observatories such as Kepler have provided data that can potentially revolutionize our understanding of stars. Through detailed asteroseismic analyses we are capable of determining fundamental stellar parameters and reveal the stellar internal structure with unprecedented accuracy. However......, such detailed analyses, known as peak bagging, have so far been obtained for only a small percentage of the observed stars while most of the scientific potential of the available data remains unexplored. One of the major challenges in peak bagging is identifying how many solar-like oscillation modes are visible...... of detected oscillation modes. The algorithm presented here opens the possibility for detailed and automated peak bagging of the thousands of solar-like oscillators observed by Kepler....

  6. Automated asteroseismic peak detections

    Science.gov (United States)

    García Saravia Ortiz de Montellano, Andrés; Hekker, S.; Themeßl, N.

    2018-05-01

    Space observatories such as Kepler have provided data that can potentially revolutionize our understanding of stars. Through detailed asteroseismic analyses we are capable of determining fundamental stellar parameters and reveal the stellar internal structure with unprecedented accuracy. However, such detailed analyses, known as peak bagging, have so far been obtained for only a small percentage of the observed stars while most of the scientific potential of the available data remains unexplored. One of the major challenges in peak bagging is identifying how many solar-like oscillation modes are visible in a power density spectrum. Identification of oscillation modes is usually done by visual inspection that is time-consuming and has a degree of subjectivity. Here, we present a peak-detection algorithm especially suited for the detection of solar-like oscillations. It reliably characterizes the solar-like oscillations in a power density spectrum and estimates their parameters without human intervention. Furthermore, we provide a metric to characterize the false positive and false negative rates to provide further information about the reliability of a detected oscillation mode or the significance of a lack of detected oscillation modes. The algorithm presented here opens the possibility for detailed and automated peak bagging of the thousands of solar-like oscillators observed by Kepler.

  7. Reduction of peak plantar pressure in people with diabetes-related peripheral neuropathy: an evaluation of the DH Pressure Relief Shoe™

    Directory of Open Access Journals (Sweden)

    Raspovic Anita

    2012-10-01

    Full Text Available Abstract Background Offloading plantar pressure is a key strategy for the prevention or healing of neuropathic plantar ulcers in diabetes. Non-removable walking casts, such as total contact casts, are currently considered the gold-standard for offloading this type of wound. However, alternative methods for offloading that are more cost effective and easier to use are continually being sought. The aim of this study was to evaluate the capacity of the DH Pressure Relief Shoe™ to offload high pressure areas under the neuropathic foot in diabetes. Methods A within-subjects, repeated measures design was used. Sixteen participants with diabetic peripheral neuropathy were recruited and three footwear conditions were evaluated in a randomised order: a canvas shoe (the control, the participants’ own standard shoe, and the DH Pressure Relief Shoe™. The primary outcome was peak plantar pressure, measured using the pedar-X® mobile in-shoe system between the three conditions. Results Data analysis was conducted on 14 out of the 16 participants because two participants could not complete data collection. The mean peak pressure values in kPa (±SD for each condition were: control shoe 315.9 (±140.7, participants’ standard shoe 273.0 (±127.1 and DH Pressure Relief Shoe™ 155.4 (±89.9. There was a statistically significant difference in peak plantar pressure between the DH Pressure Relief Shoe™ compared to both the control shoe (p = 0.002 and participants’ standard shoe (p = 0.001. The DH Pressure Relief Shoe™ decreased plantar pressures by 51% compared to the control shoe and by 43% compared to participants’ standard shoe. Importantly, for a couple of study participants, the DH Pressure Relief Shoe™ appeared unsuitable for day-to-day wearing. Conclusions The DH Pressure Relief Shoe™ reduced plantar pressures more than the other two shoe conditions. The DH Pressure Relief Shoe™ may be a useful alternative to current offloading

  8. Safety Evaluation Report related to the operation of Comanche Peak Steam Electric Station, Units 1 and 2 (Docket Nos. 50-445 and 50-446). Supplement No. 8

    International Nuclear Information System (INIS)

    1985-02-01

    Supplement 8 to the Safety Evaluation Report for the Texas Utilities Electric Company application for a license to operate Comanche Peak Steam Electric Station, Units 1 and 2 (Docket Nos. 50-445, 50-446), located in Somervell County, Texas, has been jointly prepared by the Office of Nuclear Reactor Regulation and the Comanche Peak Technical Review Team of the US Nuclear Regulatory Commission. This Supplement provides the results of the staff's evaluation and resolution of approximately 80 technical concerns and allegations relating to civil and structural and miscellaneous issues regarding construction and plant readiness testing practices at the Comanche Peak facility. Issues raised during recent Atomic Safety and Licensing Board hearings will be dealt with in future supplements to the Safety Evaluation Report

  9. Effect of single physical exercise at 35% VO2 max. intensity on secretion activity of pancreas β-cells and 125J-insulin binding and degradation ability by erythrocyte receptors in children with diabetes mellitus

    International Nuclear Information System (INIS)

    Szczesniak, L.; Rychlewski, T.; Banaszak, F.; Kasprzak, Z.; Walczak, M.

    1994-01-01

    In this report we showed research results of effect of single physical exercise on cycloergometer at 35% VO 2 max. intensity on 125 J-insulin binding and degradation ability by erythrocyte receptors in children with diabetes mellitus, secreting and non-secreting endogenous insulin. Insulin secretion was evaluated by measurement of C-peptide by Biodet test (Serono) of sensitivity threshold at 0.3 μg/ml. We indicated in children non-secreting endogenous insulin (n=32) there is statistically essential lower 125 J-insulin binding with erythrocyte receptor in comparison to children group with C-peptide. Physical exercise on cycloergometer at 35% VO 2 max. intensity caused different reaction in range of physiological indices, like acid-base parameters, level of glucose and 125 J-insulin binding and degradation. In children devoid of endogenous insulin we indicated statistically nonessential changes in 125 J-insulin degradation by non-impaired erythrocytes and by hemolizate, as well. 125 J-insulin binding after physical exercise increased in both groups, though change amplitude was different. Obtained research results allowed us to conclude, in children with I-type diabetes, that in dependence of impairment degree of pancreas βcells sensitivity of insulin receptor and/or number of receptors on erythrocyte surface is different

  10. Evaluation of concurrent peak responses

    International Nuclear Information System (INIS)

    Wang, P.C.; Curreri, J.; Reich, M.

    1983-01-01

    This report deals with the problem of combining two or more concurrent responses which are induced by dynamic loads acting on nuclear power plant structures. Specifically, the acceptability of using the square root of the sum of the squares (SRSS) value of peak values as the combined response is investigated. Emphasis is placed on the establishment of a simplified criterion that is convenient and relatively easy to use by design engineers

  11. 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...

  12. Daily physical activity and its relation to aerobic fitness in children aged 8-11 years

    DEFF Research Database (Denmark)

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

    2006-01-01

    and fitness in children has been published, where fitness has been assessed by direct measurement of maximum oxygen uptake and related to daily physical activity intensities by accelerometers. We examined 248 children (140 boys and 108 girls), aged 7.9-11.1 years. Maximum workload and maximal oxygen uptake...... in vigorous physical activity were calculated. VO2PEAK was correlated with mean accelerometer counts (r=0.23 for boys and r=0.23 for girls, both Pactivity (r=0.32 for boys, r=0.30 for girls, both P...Abstract  A positive relationship between daily physical activity and aerobic fitness exists in adults. Studies in children have given conflicting results, possibly because of differences in methods used to assess daily physical activity and fitness. No study regarding daily physical activity...

  13. Nano-regime Length Scales Extracted from the First Sharp Diffraction Peak in Non-crystalline SiO2 and Related Materials: Device Applications

    Directory of Open Access Journals (Sweden)

    Phillips James

    2010-01-01

    Full Text Available Abstract This paper distinguishes between two different scales of medium range order, MRO, in non-crystalline SiO2: (1 the first is ~0.4 to 0.5 nm and is obtained from the position of the first sharp diffraction peak, FSDP, in the X-ray diffraction structure factor, S(Q, and (2 the second is ~1 nm and is calculated from the FSDP full-width-at-half-maximum FWHM. Many-electron calculations yield Si–O third- and O–O fourth-nearest-neighbor bonding distances in the same 0.4–0.5 nm MRO regime. These derive from the availability of empty Si dπ orbitals for back-donation from occupied O pπ orbitals yielding narrow symmetry determined distributions of third neighbor Si–O, and fourth neighbor O–O distances. These are segments of six member rings contributing to connected six-member rings with ~1 nm length scale within the MRO regime. The unique properties of non-crystalline SiO2 are explained by the encapsulation of six-member ring clusters by five- and seven-member rings on average in a compliant hard-soft nano-scaled inhomogeneous network. This network structure minimizes macroscopic strain, reducing intrinsic bonding defects as well as defect precursors. This inhomogeneous CRN is enabling for applications including thermally grown ~1.5 nm SiO2 layers for Si field effect transistor devices to optical components with centimeter dimensions. There are qualitatively similar length scales in nano-crystalline HfO2 and phase separated Hf silicates based on the primitive unit cell, rather than a ring structure. Hf oxide dielectrics have recently been used as replacement dielectrics for a new generation of Si and Si/Ge devices heralding a transition into nano-scale circuits and systems on a Si chip.

  14. Peak reading detector circuit

    International Nuclear Information System (INIS)

    Courtin, E.; Grund, K.; Traub, S.; Zeeb, H.

    1975-01-01

    The peak reading detector circuit serves for picking up the instants during which peaks of a given polarity occur in sequences of signals in which the extreme values, their time intervals, and the curve shape of the signals vary. The signal sequences appear in measuring the foetal heart beat frequence from amplitude-modulated ultrasonic, electrocardiagram, and blood pressure signals. In order to prevent undesired emission of output signals from, e. g., disturbing intermediate extreme values, the circuit consists of the series connections of a circuit to simulate an ideal diode, a strong unit, a discriminator for the direction of charging current, a time-delay circuit, and an electronic switch lying in the decharging circuit of the storage unit. The time-delay circuit thereby causes storing of a preliminary maximum value being used only after a certain time delay for the emission of the output signal. If a larger extreme value occurs during the delay time the preliminary maximum value is cleared and the delay time starts running anew. (DG/PB) [de

  15. Análise de lesão muscular e comportamento do vo2máx entre um programa de treinamento de corrida em piscina funda e corrida em terra

    Directory of Open Access Journals (Sweden)

    Alecsandra Pinheiro Vendrusculo

    2014-12-01

    Full Text Available Objetivo: avaliar e comparar a ocorrência de lesão muscular e o comportamento do consumo máximo de oxigênio (VO2máx entre um programa de treinamento de corrida em terra (CT e um programa de treinamento de corrida em piscina funda (CPF. Método: participaram do estudo 14 indivíduos não treinados. O treinamento durou 12 semanas, três vezes na semana. Analisou-se o comportamento do VO2máx pré e pós-treinamento. Para a análise de lesão muscular utilizou-se a enzima creatina quinase (CK pré, logo após, pós 24h e 48h da sessão, a cada quatro semanas e a ultrassonografia (US a cada quatro semanas. Resultados: Quando se analisou o comportamento do VO2máx, verificou-se diferença entre os valores pré e pós-treinamento, mas não houve diferença entre os grupos. Quanto à CK, verificou-se diferença entre os grupos na medida 24hs após, o que não foi verificado nas outras medidas. Para o grupo CT, somente nas coletas dois e quatro verificou-se diferença entre as medidas 24hs após e 48hs após, mas não ocorreram diferenças significativas entre as medidas e nem entre os grupos. Na US, nenhum dos grupos apresentou diferença significativa entre os exames, mas no grupo CT apareceram duas lesões na terceira coleta. Considerações finais: concluiu-se que as duas modalidades de treinamento proporcionam uma melhora na aptidão cardiorrespiratória e, embora não tenha ocorrido diferença significativa em algumas coletas de CK entre os grupos, a CT provocou maiores aumentos na concentração sanguínea de CK, sugerindo que o meio líquido pode ser o mais indicado para proteger o sistema musculoesquelético.

  16. Safety Evaluation Report related to the operation of Comanche Peak Steam Electric Station, Units 1 and 2 (Docket Nos. 50-445 and 50-446). Supplement No. 11

    International Nuclear Information System (INIS)

    1985-05-01

    Supplement 11 to the Safety Evaluation Report for the Texas Utilities Electric Company application for a license to operate Comanche Peak Steam Electric Station, Units 1 and 2 (Docket Nos. 50-445, 50-446), located in Somervell County, Texas, has been jointly prepared by the Office of Nuclear Reactor Regulation and the Comanche Peak Technical Review Team (TRT) of the US Nuclear Regulatory Commission (NRC) and is in two parts. Part 1 (Appendix 0) of this supplement provides the results of the TRT's evaluation of approximately 124 concerns and allegations relating specifically to quality assurance and quality control (QA/QC) issues regarding construction proctices at the Comanche Peak facility. Part 2 (Appendix P) contains an overall summary and conclusion of the QA/QC aspects of the NRC Technical Review Team efforts as reported in supplemental Safety Evaluation Report SERs 7, 8, 9, and 10. Since QA/QC issues are also contained in each of the other supplements, the TRT considered that such a summary and conclusion from all supplements was necessary for a complete TRT description of QA/QC activities at Comanche Peak

  17. Relative thermoluminescent efficiencies proton/gamma and helium/gamma of high temperature peaks in TLD-100 dosemeters; Eficiencias termoluminiscentes relativas proton/gamma y helio/gamma de picos de alta temperatura en dosimetros TLD-100

    Energy Technology Data Exchange (ETDEWEB)

    Flores M, E.; Avila, O.; Rodriguez V, M. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico); Massillon, J.L.G.; Buenfil A, E.; Ruiz T, C.; Brandan, M.E. [IFUNAM, 04500 Mexico D.F. (Mexico); Gamboa De Buen, I. [ICN-UNAM, 04500 Mexico D.F. (Mexico)

    2007-07-01

    This work presents measures of relative thermoluminescent efficiency of those high temperature peaks of TLD-100 dosemeters exposed to protons of 1.5 MeV and to helium nuclei of 3 and 7.5 MeV. A rigorous reading and of deconvolution protocol was used for the calculation of the TL efficiencies. Additionally an Excel program that facilitated the deconvolution adjustment process of the glow curves was elaborated. (Author)

  18. Effects of Aerobic, Strength or Combined Exercise on Perceived Appetite and Appetite-Related Hormones in Inactive Middle-Aged Men.

    Science.gov (United States)

    Larsen, Penelope S; Donges, Cheyne E; Guelfi, Kym J; Smith, Greg C; Adams, David R; Duffield, Rob

    2017-10-01

    Aerobic exercise (AE) and strength exercise (SE) are reported to induce discrete and specific appetite-related responses; however, the effect of combining AE and SE (i.e., combined exercise; CE) remains relatively unknown. Twelve inactive overweight men (age: 48 ± 5 y; BMI: 29.9 ± 1.9 kg∙m 2 ) completed four conditions in a random order: 1) nonexercise control (CON) (50 min seated rest); 2) AE (50 min cycling; 75% VO 2peak ); 3) SE (10 × 8 leg extensions; 75% 1RM); and 4) CE (50% SE + 50% AE). Perceived appetite, and appetiterelated peptides and metabolites were assessed before and up to 2 h postcondition (0P, 30P, 60P, 90P, 120P). Perceived appetite did not differ between trials (p appetite-related peptides and metabolites. Despite these differential exercise-induced hormone responses, exercise mode appears to have little effect on perceived appetite compared with a resting control in this population.

  19. Employer Attitudes towards Peak Hour Avoidance

    NARCIS (Netherlands)

    Vonk Noordegraaf, D.M.; Annema, J.A.

    2012-01-01

    Peak Hour Avoidance is a relatively new Dutch mobility management measure. To reduce congestion frequent car drivers are given a financial reward for reducing the proportion of trips that they make during peak hours on a specific motorway section. Although previous studies show that employers are

  20. Employer attitudes towards peak hour avoidance

    NARCIS (Netherlands)

    Noordegraaf, D.M.V.; Annema, J.A.

    2012-01-01

    Peak Hour Avoidance is a relatively new Dutch mobility management measure. To reduce congestion frequent car drivers are given a financial reward for reducing the proportion of trips that they make during peak hours on a specific motorway section. Although previous studies show that employers are

  1. High content of MYHC II in vastus lateralis is accompanied by higher VO2/power output ratio during moderate intensity cycling performed both at low and at high pedalling rates.

    Science.gov (United States)

    Majerczak, J; Szkutnik, Z; Karasinski, J; Duda, K; Kolodziejski, L; Zoladz, J A

    2006-06-01

    The aim of this study was to examine the relationship between the content of various types of myosin heavy chain isoforms (MyHC) in the vastus lateralis muscle and pulmonary oxygen uptake during moderate power output incremental exercise, performed at low and at high pedalling rates. Twenty one male subjects (mean +/- SD) aged 24.1 +/- 2.8 years; body mass 72.9 +/- 7.2 kg; height 179.1 +/- 4.8 cm; BMI 22.69 +/- 1.89 kg.m(-2); VO2max 50.6 +/- 5.3 ml.kg.min(-1), participated in this study. On separate days, they performed two incremental exercise tests at 60 rev.min(-1) and at 120 rev.min(-1), until exhaustion. Gas exchange variables were measured continuously breath by breath. Blood samples were taken for measurements of plasma lactate concentration prior to the exercise test and at the end of each step of the incremental exercise. Muscle biopsies were taken from the vastus lateralis muscle, using Bergström needle, and they were analysed for the content of MyHC I and MyHC II using SDS--PAGE and two groups (n=7, each) were selected: group H with the highest content of MyHC II (60.7 % +/- 10.5 %) and group L with the lowest content of MyHC II (27.6 % +/- 6.1 %). We have found that during incremental exercise at the power output between 30-120 W, performed at 60 rev.min(-1), oxygen uptake in the group H was significantly greater than in the group L (ANCOVA, p=0.003, upward shift of the intercept in VO2/power output relationship). During cycling at the same power output but at 120 rev.min(-1), the oxygen uptake was also higher in the group H, when compared to the group L (i.e. upward shift of the intercept in VO2/power output relationship, ANCOVA, p=0.002). Moreover, the increase in pedalling rate from 60 to 120 rev.min(-1) was accompanied by a significantly higher increase of oxygen cost of cycling and by a significantly higher plasma lactate concentration in subjects from group H. We concluded that the muscle mechanical efficiency, expressed by the VO2/PO ratio

  2. Physico - chemical investigation on Co(II), Ni(II), Cu(II), Zn(II), Cd(II), UO2+2 and VO+2 ions-O-(-N-3,5-dichloro-α-pyridone imino)

    International Nuclear Information System (INIS)

    Mathur, Praveen; Trivedi, Pradeep; Mehta, R.K.

    1983-01-01

    Studies on the interaction of newly synthesised ligand, O-(N-3, 5-dichloro-α-pyridone imino) benzene sulphonic acid (H 2 PB) with Co(II), Ni(II), Cu(II), Zn(II), Cd(II), UO 2 +2 and VO +2 have been carried out potentiometrically. Many physico-chemical studies on thermodynamics, elemental analysis, molecular weight, magnetic moment, conductance, electronic and IR spectra have also been made on the solid chelates and their adducts. The dissociation constants of H 2 PB and stabilities of its bivalent chelates have been evaluated potentiometrically at 25deg, 35deg and 45degC in aqueous medium (0.01M, 0.05M and 0.1M NaClO 4 ) by Bjerrum's method. The stability sequence is in agreement with the Irving-William's rule. (author)

  3. 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.

  4. Effects of long-term multicomponent exercise on health-related quality of life in older adults with type 2 diabetes: evidence from a cohort study.

    Science.gov (United States)

    Baptista, Liliana C; Dias, Gonçalo; Souza, Nelba R; Veríssimo, Manuel T; Martins, Raul A

    2017-08-01

    To establish the effect of a long-term multicomponent exercise (LTMEX) intervention (24 months) on health-related quality of life (HRQoL), in older adults with type 2 diabetes (T2D). This longitudinal retrospective cohort study analyzes the effects of a supervised LTMEX program on HRQoL in older adults with T2D (n = 279). Participants underwent one of two conditions: LTMEX (n = 241) trained three times per week; and unchanged lifestyle-the control group (CO; n = 38). Participants completed baseline, and 2-year follow-up evaluations including the Short Form Health Survey 36 (SF-36), anthropometric, hemodynamic components, and cardiorespiratory fitness (VO 2 peak). LTMEX improves HRQoL, specifically physical functioning (P health (P health (MH; P older adults with T2D, and also anthropometric, hemodynamic profile, and cardiorespiratory fitness.

  5. Multiscale peak detection in wavelet space.

    Science.gov (United States)

    Zhang, Zhi-Min; Tong, Xia; Peng, Ying; Ma, Pan; Zhang, Ming-Jin; Lu, Hong-Mei; Chen, Xiao-Qing; Liang, Yi-Zeng

    2015-12-07

    Accurate peak detection is essential for analyzing high-throughput datasets generated by analytical instruments. Derivatives with noise reduction and matched filtration are frequently used, but they are sensitive to baseline variations, random noise and deviations in the peak shape. A continuous wavelet transform (CWT)-based method is more practical and popular in this situation, which can increase the accuracy and reliability by identifying peaks across scales in wavelet space and implicitly removing noise as well as the baseline. However, its computational load is relatively high and the estimated features of peaks may not be accurate in the case of peaks that are overlapping, dense or weak. In this study, we present multi-scale peak detection (MSPD) by taking full advantage of additional information in wavelet space including ridges, valleys, and zero-crossings. It can achieve a high accuracy by thresholding each detected peak with the maximum of its ridge. It has been comprehensively evaluated with MALDI-TOF spectra in proteomics, the CAMDA 2006 SELDI dataset as well as the Romanian database of Raman spectra, which is particularly suitable for detecting peaks in high-throughput analytical signals. Receiver operating characteristic (ROC) curves show that MSPD can detect more true peaks while keeping the false discovery rate lower than MassSpecWavelet and MALDIquant methods. Superior results in Raman spectra suggest that MSPD seems to be a more universal method for peak detection. MSPD has been designed and implemented efficiently in Python and Cython. It is available as an open source package at .

  6. The road to gold: training and peaking characteristics in the year prior to a gold medal endurance performance.

    Science.gov (United States)

    Tønnessen, Espen; Sylta, Øystein; Haugen, Thomas A; Hem, Erlend; Svendsen, Ida S; Seiler, Stephen

    2014-01-01

    To describe training variations across the annual cycle in Olympic and World Champion endurance athletes, and determine whether these athletes used tapering strategies in line with recommendations in the literature. Eleven elite XC skiers and biathletes (4 male; 28±1 yr, 85±5 mL x min(-1) x kg(-1) VO2max, 7 female, 25±4 yr, 73±3 mL x min(-1) x kg(-1) VO2max) reported one year of day-to-day training leading up to the most successful competition of their career. Training data were divided into periodization and peaking phases and distributed into training forms, intensity zones and endurance activity forms. Athletes trained ∼800 h/500 sessions x year(-1), including ∼500 h x year(-1) of sport-specific training. Ninety-four percent of all training was executed as aerobic endurance training. Of this, ∼90% was low intensity training (LIT, below the first lactate threshold) and 10% high intensity training (HIT, above the first lactate threshold) by time. Categorically, 23% of training sessions were characterized as HIT with primary portions executed at or above the first lactate turn point. Training volume and specificity distribution conformed to a traditional periodization model, but absolute volume of HIT remained stable across phases. However, HIT training patterns tended to become more polarized in the competition phase. Training volume, frequency and intensity remained unchanged from pre-peaking to peaking period, but there was a 32±15% (Pphase. The annual training data for these Olympic and World champion XC skiers and biathletes conforms to previously reported training patterns of elite endurance athletes. During the competition phase, training became more sport-specific, with 92% performed as XC skiing. However, they did not follow suggested tapering practice derived from short-term experimental studies. Only three out of 11 athletes took a rest day during the final 5 days prior to their most successful competition.

  7. Safety Evaluation Report related to the operation of Comanche Peak Steam Electric Station, Units 1 and 2 (Docket Nos. 50-445 and 50-446). Supplement No. 13

    International Nuclear Information System (INIS)

    1986-05-01

    Supplement 13 to the Safety Evaluation Report related to the operation of Comanche Peak Steam Electric Station (CPSES), Units 1 and 2 (NUREG-0797), has been prepared by the Office of Nuclear Reactor Regulation of the US Nuclear Regulatory Commission (NRC). The facility is located in Somervell County, Texas, approximately 40 miles southwest of Fort Worth, Texas. This supplement presents the staff's evaluation of the Comanche Peak Response Team (CPRT) Program Plan which was formulated by the applicant to resolve various construction and design issues raised by the Atomic Safety and Licensing Board, allegers, intervenor Citizens Association for Sound Energy (CASE), NRC inspections of various types, and Cygna Energy Services while conducting its independent design assessment. The NRC staff concludes that the CPRT Program Plan provides an overall structure for addressing all existing issues and any future issues which may be identified from further evaluations, and if properly implemented will provide important evidence of the design and construction quality of CPSES, and will identify any needed corrective action. The report identifies items to be addressed by the NRC staff during the implementation phase

  8. Nanoscale Phase Separation and Lattice Complexity in VO2: The Metal–Insulator Transition Investigated by XANES via Auger Electron Yield at the Vanadium L23-Edge and Resonant Photoemission

    Directory of Open Access Journals (Sweden)

    Augusto Marcelli

    2017-12-01

    Full Text Available Among transition metal oxides, VO2 is a particularly interesting and challenging correlated electron material where an insulator to metal transition (MIT occurs near room temperature. Here we investigate a 16 nm thick strained vanadium dioxide film, trying to clarify the dynamic behavior of the insulator/metal transition. We measured (resonant photoemission below and above the MIT transition temperature, focusing on heating and cooling effects at the vanadium L23-edge using X-ray Absorption Near-Edge Structure (XANES. The vanadium L23-edges probe the transitions from the 2p core level to final unoccupied states with 3d orbital symmetry above the Fermi level. The dynamics of the 3d unoccupied states both at the L3- and at the L2-edge are in agreement with the hysteretic behavior of this thin film. In the first stage of the cooling, the 3d unoccupied states do not change while the transition in the insulating phase appears below 60 °C. Finally, Resonant Photoemission Spectra (ResPES point out a shift of the Fermi level of ~0.75 eV, which can be correlated to the dynamics of the 3d// orbitals, the electron–electron correlation, and the stability of the metallic state.

  9. An experimental and theoretical study on the interaction of DNA and BSA with novel Ni2 +, Cu2 + and VO2 + complexes derived from vanillin bidentate Schiff base ligand

    Science.gov (United States)

    Dostani, Morteza; Kianfar, Ali Hossein; Mahmood, Wan Ahmad Kamil; Dinari, Mohammad; Farrokhpour, Hossein; Sabzalian, Mohammad R.; Abyar, Fatemeh; Azarian, Mohammad Hossein

    2017-06-01

    In this investigation, the structure of bidentate N,N-Schiff base ligand of vanillin, (E)-4-(((2-amino-5-nitrophenyl)imino)methyl)-2-methoxyphenol (HL) was determined by single crystal X-ray diffraction. The interaction of new [CuL2], [NiL2] and [VOL2] complexes with DNA and BSA was explored through UV-Vis and fluorescence spectroscopy. The electronic spectra changes displayed an isosbestic point for the complexes upon titration with DNA. The Kb values for the complexes [CuL2], [NiL2] and [VOL2] were 2.4 × 105, 1.9 × 105 and 4.2 × 104, respectively. [CuL2] complex was bound more toughly than [NiL2] and [VOL2] complexes. These complexes had a significant interaction with Bovine Serum Albumin (BSA) and the results demonstrated that the quenching mechanism was a static procedure. Also, the complexes interacted with BSA by more than one binding site (n > 1). Finally, the theoretical studies were performed using the docking method to calculate the binding constants and recognize the binding site of the DNA and BSA with the complexes. The ligand and complexes including Ni2 +, Cu2 + and VO2 + ions were colonized by fungal growth.

  10. Safety evaluation report related to the operation of Comanche Peak Steam Electric Station, Units 1 and 2 (Docket Nos. 50-445 and 50-446): Supplement No. 21

    International Nuclear Information System (INIS)

    1989-04-01

    Supplement 21 to the Safety Evaluation Report related to the operation of the Comanche Peak Steam Electric Station (CPSES), Units 1 and 2 (NUREG-0797), has been prepared by the Office of Nuclear Reactor Regulation of the US Nuclear Regulatory Commission (NRC). The facility is located in Somervell County, Texas, approximately 40 miles southwest of Fort Worth, Texas. This supplement reports the status of certain issues that had not been resolved when the Safety Evaluation Report and Supplements 1, 2, 3, 4, 6, and 12 to that report were published. This supplement also lists the new issues that have been identified since Supplement 12 was issued and includes the evaluations for licensing items resolved in this interim period. 21 refs

  11. Instream flow needs below peaking hydroelectric projects

    International Nuclear Information System (INIS)

    Milhous, R.T.

    1991-01-01

    This paper reports on a method developed to assist in the determination of instream flow needs below hydroelectric projects operated in a peaking mode. Peaking hydroelectric projects significantly change streamflow over a short period of time; consequently, any instream flow methodology must consider the dual flows associated with peaking projects. The dual flows are the lowest flow and the maximum generation flow of a peaking cycle. The methodology is based on elements of the Physical Habitat Simulation System of the U.S. Fish and Wildlife Service and uses habitat, rather than fish numbers or biomas, as at basic response variable. All aquatic animals are subject to the rapid changes in streamflow which cause rapid swings in habitat quality. Some aquatic organisms are relatively fixed in location in the stream while others can move when flows change. The habitat available from a project operated in peaking mode is considered to be the minimum habitat occurring during a cycle of habitat change. The methodology takes in to consideration that some aquatic animals can move and others cannot move during a peaking cycle

  12. Neurofeedback training for peak performance

    Directory of Open Access Journals (Sweden)

    Marek Graczyk

    2014-11-01

    Full Text Available [b]aim[/b]. One of the applications of the Neurofeedback methodology is peak performance in sport. The protocols of the neurofeedback are usually based on an assessment of the spectral parameters of spontaneous EEG in resting state conditions. The aim of the paper was to study whether the intensive neurofeedback training of a well-functioning Olympic athlete who has lost his performance confidence after injury in sport, could change the brain functioning reflected in changes in spontaneous EEG and event related potentials (ERPs. [b]case study[/b]. The case is presented of an Olympic athlete who has lost his performance confidence after injury in sport. He wanted to resume his activities by means of neurofeedback training. His QEEG/ERP parameters were assessed before and after 4 intensive sessions of neurotherapy. Dramatic and statistically significant changes that could not be explained by error measurement were observed in the patient. [b]conclusion[/b]. Neurofeedback training in the subject under study increased the amplitude of the monitoring component of ERPs generated in the anterior cingulate cortex, accompanied by an increase in beta activity over the medial prefrontal cortex. Taking these changes together, it can be concluded that that even a few sessions of neurofeedback in a high performance brain can significantly activate the prefrontal cortical areas associated with increasing confidence in sport performance.

  13. Neurofeedback training for peak performance.

    Science.gov (United States)

    Graczyk, Marek; Pąchalska, Maria; Ziółkowski, Artur; Mańko, Grzegorz; Łukaszewska, Beata; Kochanowicz, Kazimierz; Mirski, Andrzej; Kropotov, Iurii D

    2014-01-01

    One of the applications of the Neurofeedback methodology is peak performance in sport. The protocols of the neurofeedback are usually based on an assessment of the spectral parameters of spontaneous EEG in resting state conditions. The aim of the paper was to study whether the intensive neurofeedback training of a well-functioning Olympic athlete who has lost his performance confidence after injury in sport, could change the brain functioning reflected in changes in spontaneous EEG and event related potentials (ERPs). The case is presented of an Olympic athlete who has lost his performance confidence after injury in sport. He wanted to resume his activities by means of neurofeedback training. His QEEG/ERP parameters were assessed before and after 4 intensive sessions of neurotherapy. Dramatic and statistically significant changes that could not be explained by error measurement were observed in the patient. Neurofeedback training in the subject under study increased the amplitude of the monitoring component of ERPs generated in the anterior cingulate cortex, accompanied by an increase in beta activity over the medial prefrontal cortex. Taking these changes together, it can be concluded that that even a few sessions of neurofeedback in a high performance brain can significantly activate the prefrontal cortical areas associated with increasing confidence in sport performance.

  14. Upper limit of peak area

    International Nuclear Information System (INIS)

    Helene, O.A.M.

    1982-08-01

    The determination of the upper limit of peak area in a multi-channel spectra, with a known significance level is discussed. This problem is specially important when the peak area is masked by the background statistical fluctuations. The problem is exactly solved and, thus, the results are valid in experiments with small number of events. The results are submitted to a Monte Carlo test and applied to the 92 Nb beta decay. (Author) [pt

  15. Peak Oil and other threatening peaks-Chimeras without substance

    International Nuclear Information System (INIS)

    Radetzki, Marian

    2010-01-01

    The Peak Oil movement has widely spread its message about an impending peak in global oil production, caused by an inadequate resource base. On closer scrutiny, the underlying analysis is inconsistent, void of a theoretical foundation and without support in empirical observations. Global oil resources are huge and expanding, and pose no threat to continuing output growth within an extended time horizon. In contrast, temporary or prolonged supply crunches are indeed plausible, even likely, on account of growing resource nationalism denying access to efficient exploitation of the existing resource wealth.

  16. Electricity Portfolio Management: Optimal Peak / Off-Peak Allocations

    OpenAIRE

    Huisman, Ronald; Mahieu, Ronald; Schlichter, Felix

    2007-01-01

    textabstractElectricity purchasers manage a portfolio of contracts in order to purchase the expected future electricity consumption profile of a company or a pool of clients. This paper proposes a mean-variance framework to address the concept of structuring the portfolio and focuses on how to allocate optimal positions in peak and off-peak forward contracts. It is shown that the optimal allocations are based on the difference in risk premiums per unit of day-ahead risk as a measure of relati...

  17. Ultrasonic Transducer Peak-to-Peak Optical Measurement

    Directory of Open Access Journals (Sweden)

    Pavel Skarvada

    2012-01-01

    Full Text Available Possible optical setups for measurement of the peak-to-peak value of an ultrasonic transducer are described in this work. The Michelson interferometer with the calibrated nanopositioner in reference path and laser Doppler vibrometer were used for the basic measurement of vibration displacement. Langevin type of ultrasonic transducer is used for the purposes of Electro-Ultrasonic Nonlinear Spectroscopy (EUNS. Parameters of produced mechanical vibration have to been well known for EUNS. Moreover, a monitoring of mechanical vibration frequency shift with a mass load and sample-transducer coupling is important for EUNS measurement.

  18. Electric peak power forecasting by year 2025

    International Nuclear Information System (INIS)

    Alsayegh, O.A.; Al-Matar, O.A.; Fairouz, F.A.; Al-Mulla Ali, A.

    2005-01-01

    Peak power demand in Kuwait up to the year 2025 was predicted using an artificial neural network (ANN) model. The aim of the study was to investigate the effect of air conditioning (A/C) units on long-term power demand. Five socio-economic factors were selected as inputs for the simulation: (1) gross national product, (2) population, (3) number of buildings, (4) imports of A/C units, and (5) index of industrial production. The study used socio-economic data from 1978 to 2000. Historical data of the first 10 years of the studied time period were used to train the ANN. The electrical network was then simulated to forecast peak power for the following 11 years. The calculated error was then used for years in which power consumption data were not available. The study demonstrated that average peak power rates increased by 4100 MW every 5 years. Various scenarios related to changes in population, the number of buildings, and the quantity of A/C units were then modelled to estimate long-term peak power demand. Results of the study demonstrated that population had the strongest impact on future power demand, while the number of buildings had the smallest impact. It was concluded that peak power growth can be controlled through the use of different immigration policies, increased A/C efficiency, and the use of vertical housing. 7 refs., 2 tabs., 6 figs

  19. Electric peak power forecasting by year 2025

    Energy Technology Data Exchange (ETDEWEB)

    Alsayegh, O.A.; Al-Matar, O.A.; Fairouz, F.A.; Al-Mulla Ali, A. [Kuwait Inst. for Scientific Research, Kuwait City (Kuwait). Div. of Environment and Urban Development

    2005-07-01

    Peak power demand in Kuwait up to the year 2025 was predicted using an artificial neural network (ANN) model. The aim of the study was to investigate the effect of air conditioning (A/C) units on long-term power demand. Five socio-economic factors were selected as inputs for the simulation: (1) gross national product, (2) population, (3) number of buildings, (4) imports of A/C units, and (5) index of industrial production. The study used socio-economic data from 1978 to 2000. Historical data of the first 10 years of the studied time period were used to train the ANN. The electrical network was then simulated to forecast peak power for the following 11 years. The calculated error was then used for years in which power consumption data were not available. The study demonstrated that average peak power rates increased by 4100 MW every 5 years. Various scenarios related to changes in population, the number of buildings, and the quantity of A/C units were then modelled to estimate long-term peak power demand. Results of the study demonstrated that population had the strongest impact on future power demand, while the number of buildings had the smallest impact. It was concluded that peak power growth can be controlled through the use of different immigration policies, increased A/C efficiency, and the use of vertical housing. 7 refs., 2 tabs., 6 figs.

  20. Peaking-factor of PWR

    International Nuclear Information System (INIS)

    Morioka, Noboru; Kato, Yasuji; Yokoi, M.

    1975-01-01

    Output peaking factor often plays an important role in the safety and operation of nuclear reactors. The meaning of the peaking factor of PWRs is categorized into two features or the peaking factor in core (FQ-core) and the peaking factor on the basis of accident analysis (or FQ-limit). FQ-core is the actual peaking factor realized in nuclear core at the time of normal operation, and FQ-limit should be evaluated from loss of coolant accident and other abnormal conditions. If FQ-core is lower than FQ-limit, the reactor may be operated at full load, but if FQ-core is larger than FQ-limit, reactor output should be controlled lower than FQ-limit. FQ-core has two kinds of values, or the one on the basis of nuclear design, and the other actually measured in reactor operation. The first FQ-core should be named as FQ-core-design and the latter as FQ-core-measured. The numerical evaluation of FQ-core-design is as follows; FQ-core-design of three-dimensions is synthesized with FQ-core horizontal value (X-Y) and FQ-core vertical value, the former one is calculated with ASSY-CORE code, and the latter one with one dimensional diffusion code. For the evaluation of FQ-core-measured, on-site data observation from nuclear reactor instrumentation or off-site data observation is used. (Iwase, T.)

  1. How to use your peak flow meter

    Science.gov (United States)

    ... meter - how to use; Asthma - peak flow meter; Reactive airway disease - peak flow meter; Bronchial asthma - peak ... 2014:chap 55. National Asthma Education and Prevention Program website. How to use a peak flow meter. ...

  2. Peak effect in twinned superconductors

    International Nuclear Information System (INIS)

    Larkin, A.I.; Marchetti, M.C.; Vinokur, V.M.

    1995-01-01

    A sharp maximum in the critical current J c as a function of temperature just below the melting point of the Abrikosov flux lattice has recently been observed in both low- and high-temperature superconductors. This peak effect is strongest in twinned crystals for fields aligned with the twin planes. We propose that this peak signals the breakdown of the collective pinning regime and the crossover to strong pinning of single vortices on the twin boundaries. This crossover is very sharp and can account for the steep drop of the differential resistivity observed in experiments. copyright 1995 The American Physical Society

  3. Maximal Fat Oxidation is Related to Performance in an Ironman Triathlon

    DEFF Research Database (Denmark)

    Frandsen, Jacob; Vest, Stine Dahl; Dela, Flemming

    2017-01-01

    correlations between race time and MFO (r(2)=0.12, p2)=0.45, p2)=0.27, psignificant variables from the bivariate regression analyses were entered...... into the multiple regression models, VO2peak and MFO together explained 50% of the variation observed in race time among the 61 Ironman athletes (adj R(2)=0.50, p9 h). Furthermore, we.......0-30.1 kg/m(2)], a body fat percentage of 16.7±0.7% [8.4-30.7%] and a VO2peak of 58.7±0.7 ml/min/kg [43.9-72.5 ml/min/kg] SEM [Range]) were tested in the laboratory between 25 and 4 days prior to the ultra-endurance event, 2016 Ironman Copenhagen. Simple bivariate analyses revealed significant negative...

  4. Altered gas-exchange at peak exercise in obese adolescents: implications for verification of effort during cardiopulmonary exercise testing.

    Science.gov (United States)

    Marinus, Nastasia; Bervoets, Liene; Massa, Guy; Verboven, Kenneth; Stevens, An; Takken, Tim; Hansen, Dominique

    2017-12-01

    Cardiopulmonary exercise testing is advised ahead of exercise intervention in obese adolescents to assess medical safety of exercise and physical fitness. Optimal validity and reliability of test results are required to identify maximal exercise effort. As fat oxidation during exercise is disturbed in obese individuals, it remains an unresolved methodological issue whether the respiratory gas exchange ratio (RER) is a valid marker for maximal effort during exercise testing in this population. RER during maximal exercise testing (RERpeak), and RER trajectories, was compared between obese and lean adolescents and relationships between RERpeak, RER slope and subject characteristics (age, gender, Body Mass Index [BMI], Tanner stage, physical activity level) were explored. Thirty-four obese (BMI: 35.1±5.1 kg/m²) and 18 lean (BMI: 18.8±1.9 kg/m²) adolescents (aged 12-18 years) performed a maximal cardiopulmonary exercise test on bike, with comparison of oxygen uptake (VO2), heart rate (HR), expiratory volume (VE), carbon dioxide output (VCO2), and cycling power output (W). RERpeak (1.09±0.06 vs. 1.14±0.06 in obese vs. lean adolescents, respectively) and RER slope (0.03±0.01 vs. 0.05±0.01 per 10% increase in VO2, in obese vs. lean adolescents, respectively) was significantly lower in obese adolescents, and independently related to BMI (Pexercise testing in this population.

  5. Hubbert's Peak -- A Physicist's View

    Science.gov (United States)

    McDonald, Richard

    2011-04-01

    Oil, as used in agriculture and transportation, is the lifeblood of modern society. It is finite in quantity and will someday be exhausted. In 1956, Hubbert proposed a theory of resource production and applied it successfully to predict peak U.S. oil production in 1970. Bartlett extended this work in publications and lectures on the finite nature of oil and its production peak and depletion. Both Hubbert and Bartlett place peak world oil production at a similar time, essentially now. Central to these analyses are estimates of total ``oil in place'' obtained from engineering studies of oil reservoirs as this quantity determines the area under the Hubbert's Peak. Knowing the production history and the total oil in place allows us to make estimates of reserves, and therefore future oil availability. We will then examine reserves data for various countries, in particular OPEC countries, and see if these data tell us anything about the future availability of oil. Finally, we will comment on synthetic oil and the possibility of carbon-neutral synthetic oil for a sustainable future.

  6. Peak capacity and peak capacity per unit time in capillary and microchip zone electrophoresis.

    Science.gov (United States)

    Foley, Joe P; Blackney, Donna M; Ennis, Erin J

    2017-11-10

    The origins of the peak capacity concept are described and the important contributions to the development of that concept in chromatography and electrophoresis are reviewed. Whereas numerous quantitative expressions have been reported for one- and two-dimensional separations, most are focused on chromatographic separations and few, if any, quantitative unbiased expressions have been developed for capillary or microchip zone electrophoresis. Making the common assumption that longitudinal diffusion is the predominant source of zone broadening in capillary electrophoresis, analytical expressions for the peak capacity are derived, first in terms of migration time, diffusion coefficient, migration distance, and desired resolution, and then in terms of the remaining underlying fundamental parameters (electric field, electroosmotic and electrophoretic mobilities) that determine the migration time. The latter expressions clearly illustrate the direct square root dependence of peak capacity on electric field and migration distance and the inverse square root dependence on solute diffusion coefficient. Conditions that result in a high peak capacity will result in a low peak capacity per unit time and vice-versa. For a given symmetrical range of relative electrophoretic mobilities for co- and counter-electroosmotic species (cations and anions), the peak capacity increases with the square root of the electric field even as the temporal window narrows considerably, resulting in a significant reduction in analysis time. Over a broad relative electrophoretic mobility interval [-0.9, 0.9], an approximately two-fold greater amount of peak capacity can be generated for counter-electroosmotic species although it takes about five-fold longer to do so, consistent with the well-known bias in migration time and resolving power for co- and counter-electroosmotic species. The optimum lower bound of the relative electrophoretic mobility interval [μ r,Z , μ r,A ] that provides the maximum

  7. Health-related physical fitness and weight status in 13- to 15-year-old Latino adolescents. A pooled analysis.

    Science.gov (United States)

    García-Hermoso, Antonio; Correa-Bautista, Jorge E; Olloquequi, Jordi; Ramírez-Vélez, Robinson

    2018-05-05

    The aim of this study was to investigate the relation between health-related physical fitness and weight status in 13- to 15-year-old Latino adolescents. The final sample consisted of 73,561 adolescents aged 13-15 years (35,175 girls) from Chile (n=48,771) and Colombia (n=24,790). Cardiorespiratory and musculoskeletal fitness were measured using 20-m shuttle run (relative peak oxygen uptake - VO 2peak ) and standing broad jump test (lower body explosive strength), respectively. The International Obesity Task Force definition was used to define weight status (i.e., underweight, normal weight, overweight, and obese). The present study found an inverted J-shape relationship between body mass index, cardiorespiratory fitness, and musculoskeletal fitness in both genders and all age groups (pfitness (based on new international criterion-referenced standards) profile when compared with their normal weight peers, except in girls aged 14 (p=0.268) and 15 years (p=0.280). The present results indicate low cardiorespiratory fitness and musculoskeletal fitness levels in underweight, overweight, and obese adolescents when compared with their normal weight peers. The findings appear to suggest that exercise programs should to decrease fat mass in overweight/obese adolescents and increase muscle mass in underweight adolescents. Copyright © 2018 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

  8. SPANISH PEAKS PRIMITIVE AREA, MONTANA.

    Science.gov (United States)

    Calkins, James A.; Pattee, Eldon C.

    1984-01-01

    A mineral survey of the Spanish Peaks Primitive Area, Montana, disclosed a small low-grade deposit of demonstrated chromite and asbestos resources. The chances for discovery of additional chrome resources are uncertain and the area has little promise for the occurrence of other mineral or energy resources. A reevaluation, sampling at depth, and testing for possible extensions of the Table Mountain asbestos and chromium deposit should be undertaken in the light of recent interpretations regarding its geologic setting.

  9. Neurofeedback training for peak performance

    OpenAIRE

    Marek Graczyk; Maria Pąchalska; Artur Ziółkowski; Grzegorz Mańko; Beata Łukaszewska; Kazimierz Kochanowicz; Andrzej Mirski; Iurii D. Kropotov

    2014-01-01

    [b]aim[/b]. One of the applications of the Neurofeedback methodology is peak performance in sport. The protocols of the neurofeedback are usually based on an assessment of the spectral parameters of spontaneous EEG in resting state conditions. The aim of the paper was to study whether the intensive neurofeedback training of a well-functioning Olympic athlete who has lost his performance confidence after injury in sport, could change the brain functioning reflected in changes in spontaneou...

  10. Finding two-dimensional peaks

    International Nuclear Information System (INIS)

    Silagadze, Z.K.

    2007-01-01

    Two-dimensional generalization of the original peak finding algorithm suggested earlier is given. The ideology of the algorithm emerged from the well-known quantum mechanical tunneling property which enables small bodies to penetrate through narrow potential barriers. We merge this 'quantum' ideology with the philosophy of Particle Swarm Optimization to get the global optimization algorithm which can be called Quantum Swarm Optimization. The functionality of the newborn algorithm is tested on some benchmark optimization problems

  11. Safety Evaluation Report related to the operation of Comanche Peak Steam Electric Station, Units 1 and 2 (Docket Nos. 50-445 and 50-446). Supplement No. 7

    International Nuclear Information System (INIS)

    1985-01-01

    Supplement 7 to the Safety Evaluation Report for the Texas Utilities Electric Company application for a license to operate Comanche Peak Steam Electric Station, Units 1 and 2 (Docket Nos. 50-445, 50-446), located in Somervell County, Texas, has been jointly prepared by the Office of Nuclear Reactor Regulation and the Comanche Peak Technical Review of the US Nuclera Regulatory Commission. This supplement provides the results of the staff's evaluation and resolution of approximately 80 technical concerns and allegations in the areas of Electric/Instrumentation and Test Programs regarding construction and plant readiness testing practices at the Comanche Peak facility. Issues raised during Atomic Safety and Licensing Board hearings will be dealt with in future supplements to the Safety Evaluation Report

  12. Drivers of peak sales for pharmaceutical brands

    NARCIS (Netherlands)

    Fischer, Marc; Leeflang, Peter S. H.; Verhoef, Peter C.

    2010-01-01

    Peak sales are an important metric in the pharmaceutical industry. Specifically, managers are focused on the height-of-peak-sales and the time required achieving peak sales. We analyze how order of entry and quality affect the level of peak sales and the time-to-peak-sales of pharmaceutical brands.

  13. The relative influence of body characteristics on humid heat stress response

    NARCIS (Netherlands)

    Havenith, G.; Luttikholt, V. G.; Vrijkotte, T. G.

    1995-01-01

    The present study was designed to determine the relative importance of individual characteristics such as maximal oxygen uptake (VO2max), adiposity, DuBois body surface area (AD), surface to mass ratio (AD: mass) and body mass, for the individual's reaction to humid heat stress. For this purpose 27

  14. Monitoring Perceived Stress and Recovery in Relation to Cycling Performance in Female Athletes

    NARCIS (Netherlands)

    Otter, R. T. A.; Brink, M. S.; van der Does, H. T. D.; Lemmink, K. A. P. M.

    The purpose was to investigate perceived stress and recovery related to cycling performance of female athletes over one full year. 20 female athletes ( age, 27 +/- 8 years; VO2max, 50.3 +/- 4.6 mL center dot kg(-1) center dot min(-1)) were measured 8 times in one year to determine perceived stress

  15. The road to gold: training and peaking characteristics in the year prior to a gold medal endurance performance.

    Directory of Open Access Journals (Sweden)

    Espen Tønnessen

    Full Text Available To describe training variations across the annual cycle in Olympic and World Champion endurance athletes, and determine whether these athletes used tapering strategies in line with recommendations in the literature.Eleven elite XC skiers and biathletes (4 male; 28±1 yr, 85±5 mL x min(-1 x kg(-1 VO2max, 7 female, 25±4 yr, 73±3 mL x min(-1 x kg(-1 VO2max reported one year of day-to-day training leading up to the most successful competition of their career. Training data were divided into periodization and peaking phases and distributed into training forms, intensity zones and endurance activity forms.Athletes trained ∼800 h/500 sessions x year(-1, including ∼500 h x year(-1 of sport-specific training. Ninety-four percent of all training was executed as aerobic endurance training. Of this, ∼90% was low intensity training (LIT, below the first lactate threshold and 10% high intensity training (HIT, above the first lactate threshold by time. Categorically, 23% of training sessions were characterized as HIT with primary portions executed at or above the first lactate turn point. Training volume and specificity distribution conformed to a traditional periodization model, but absolute volume of HIT remained stable across phases. However, HIT training patterns tended to become more polarized in the competition phase. Training volume, frequency and intensity remained unchanged from pre-peaking to peaking period, but there was a 32±15% (P<.01 volume reduction from the preparation period to peaking phase.The annual training data for these Olympic and World champion XC skiers and biathletes conforms to previously reported training patterns of elite endurance athletes. During the competition phase, training became more sport-specific, with 92% performed as XC skiing. However, they did not follow suggested tapering practice derived from short-term experimental studies. Only three out of 11 athletes took a rest day during the final 5 days prior to

  16. Safety Evaluation Report related to the operation of Comanche Peak Steam Electric Station, Units 1 and 2 (Docket Nos. 50-445 and 50-446). Supplement No. 10

    International Nuclear Information System (INIS)

    1985-04-01

    This Supplement provides the results of the staff's evaluation and resolution of approximately 400 technical concerns and allegations in the mechanical and piping area regarding construction practices at the Comanche Peak facility. This report does not address the Walsh/Doyle allegations regarding deficiencies in the pipe support design process and the new allegations recently received by the staff

  17. Low calcium-phosphate intakes modulate the low-protein diet-related effect on peak bone mass acquisition: a hormonal and bone strength determinants study in female growing rats.

    Science.gov (United States)

    Fournier, C; Rizzoli, R; Ammann, P

    2014-11-01

    Peak bone mass acquisition is influenced by environmental factors including dietary intake. A low-protein diet delays body and skeletal growth in association with a reduction in serum IGF-1 whereas serum FGF21 is increased by selective amino acid deprivation. Calcium (Ca) and phosphorous (P) are also key nutrients for skeletal health, and inadequate intakes reduce bone mass accrual in association with calciotropic hormone modulation. Besides, the effect of calcium supplementation on bone mass in prepubertal children appears to be influenced by protein intake. To further explore the interaction of dietary protein and Ca-P intake on bone growth, 1-month-old female rats were fed with an isocaloric 10%, 7.5%, or 5% casein diet containing normal or low Ca-P for an 8-week period (6 groups). Changes in tibia geometry, mineral content, microarchitecture, strength, and intrinsic bone quality were analyzed. At the hormonal level, serum IGF-1, fibroblast growth factor 21 (FGF21), PTH, 1,25-dihydroxyvitamin D3 (calcitriol), and FGF23 were investigated as well as the Ghr hepatic gene expression. In normal dietary Ca-P conditions, bone mineral content, trabecular and cortical bone volume, and bone strength were lower in the 5% casein group in association with a decrease in serum IGF-1 and an increase in FGF21 levels. Unexpectedly, the low-Ca-P diet attenuated the 5% casein diet-related reduction of serum IGF-1 and Ghr hepatic gene expression, as well as the low-protein diet-induced decrease in bone mass and strength. However, this was associated with lower cortical bone material level properties. The low-Ca-P diet increased serum calcitriol but decreased FGF23 levels. Calcitriol levels positively correlated with Ghr hepatic mRNA levels. These results suggest that hormonal modulation in response to a low-Ca-P diet may modify the low-protein diet-induced effect on Ghr hepatic mRNA levels and consequently the impact of low protein intakes on IGF-1 circulating levels and skeletal

  18. Spatial peak-load pricing

    International Nuclear Information System (INIS)

    Arellano, M. Soledad; Serra, Pablo

    2007-01-01

    This article extends the traditional electricity peak-load pricing model to include transmission costs. In the context of a two-node, two-technology electric power system, where suppliers face inelastic demand, we show that when the marginal plant is located at the energy-importing center, generators located away from that center should pay the marginal capacity transmission cost; otherwise, consumers should bear this cost through capacity payments. Since electric power transmission is a natural monopoly, marginal-cost pricing does not fully cover costs. We propose distributing the revenue deficit among users in proportion to the surplus they derive from the service priced at marginal cost. (Author)

  19. Can You Hear That Peak? Utilization of Auditory and Visual Feedback at Peak Limb Velocity

    Science.gov (United States)

    Loria, Tristan; de Grosbois, John; Tremblay, Luc

    2016-01-01

    Purpose: At rest, the central nervous system combines and integrates multisensory cues to yield an optimal percept. When engaging in action, the relative weighing of sensory modalities has been shown to be altered. Because the timing of peak velocity is the critical moment in some goal-directed movements (e.g., overarm throwing), the current study…

  20. Economic effects of peak oil

    International Nuclear Information System (INIS)

    Lutz, Christian; Lehr, Ulrike; Wiebe, Kirsten S.

    2012-01-01

    Assuming that global oil production peaked, this paper uses scenario analysis to show the economic effects of a possible supply shortage and corresponding rise in oil prices in the next decade on different sectors in Germany and other major economies such as the US, Japan, China, the OPEC or Russia. Due to the price-inelasticity of oil demand the supply shortage leads to a sharp increase in oil prices in the second scenario, with high effects on GDP comparable to the magnitude of the global financial crises in 2008/09. Oil exporting countries benefit from high oil prices, whereas oil importing countries are negatively affected. Generally, the effects in the third scenario are significantly smaller than in the second, showing that energy efficiency measures and the switch to renewable energy sources decreases the countries' dependence on oil imports and hence reduces their vulnerability to oil price shocks on the world market. - Highlights: ► National and sectoral economic effects of peak oil until 2020 are modelled. ► The price elasticity of oil demand is low resulting in high price fluctuations. ► Oil shortage strongly affects transport and indirectly all other sectors. ► Global macroeconomic effects are comparable to the 2008/2009 crisis. ► Country effects depend on oil imports and productivity, and economic structures.

  1. Fluctuations of population density in Bornean orangutans (Pongo pygmaeus morio) related to fruit availability in the Danum Valley, Sabah, Malaysia: a 10-year record including two mast fruitings and three other peak fruitings.

    Science.gov (United States)

    Kanamori, Tomoko; Kuze, Noko; Bernard, Henry; Malim, Titol Peter; Kohshima, Shiro

    2017-01-01

    We investigated the population density of Bornean orangutans (Pongo pygmaeus morio) and fruit availability for 10 years (2005-2014), in primary lowland dipterocarp forests in the Danum Valley, Sabah, Malaysia. During the research period, two mast fruitings and three other peak fruiting events of different scales occurred in the study area. The orangutan population density, estimated every 2 months by the marked nest count method, changed between 0.3 and 4.4 ind/km 2 and the mean population density was 1.3 ind/km 2  ± SE 0.1 (n = 56). The population density increased markedly during mast and peak fruiting periods. A significant positive correlation was observed between the population density and fruit availability in the study period (Spearman, R = 0.3, P < 0.01, n = 56). During non-fruiting periods, however, no significant correlation was observed between them. These results suggest that the spatial difference in fruit availability during mast and peak fruiting periods was larger than during non-fruiting periods, and many orangutans temporarily moved to the study site from the surrounding areas seeking fruit.

  2. daily nigerian nigerian nigerian peak load forec peak load forec

    African Journals Online (AJOL)

    User

    company. Basic operating functions such as u commitment, economic dispatch, fuel scheduli and unit ... analysis or contingency analysis [1]. 8035134769 ... A neural network of relatively smaller size than the main prediction relatively smaller ...

  3. Evaluation of peak power prediction equations in male basketball players.

    Science.gov (United States)

    Duncan, Michael J; Lyons, Mark; Nevill, Alan M

    2008-07-01

    This study compared peak power estimated using 4 commonly used regression equations with actual peak power derived from force platform data in a group of adolescent basketball players. Twenty-five elite junior male basketball players (age, 16.5 +/- 0.5 years; mass, 74.2 +/- 11.8 kg; height, 181.8 +/- 8.1 cm) volunteered to participate in the study. Actual peak power was determined using a countermovement vertical jump on a force platform. Estimated peak power was determined using countermovement jump height and body mass. All 4 prediction equations were significantly related to actual peak power (all p jump prediction equations, 12% for the Canavan and Vescovi equation, and 6% for the Sayers countermovement jump equation. In all cases peak power was underestimated.

  4. Daily Nigerian peak load forecasting using artificial neural network ...

    African Journals Online (AJOL)

    A daily peak load forecasting technique that uses artificial neural network with seasonal indices is presented in this paper. A neural network of relatively smaller size than the main prediction network is used to predict the daily peak load for a period of one year over which the actual daily load data are available using one ...

  5. METing SUSY on the Z peak

    Energy Technology Data Exchange (ETDEWEB)

    Barenboim, G.; Bernabeu, J.; Vives, O. [Universitat de Valencia, Departament de Fisica Teorica, Burjassot (Spain); Universitat de Valencia-CSIC, Parc Cientific U.V., IFIC, Paterna (Spain); Mitsou, V.A.; Romero, E. [Universitat de Valencia-CSIC, Parc Cientific U.V., IFIC, Paterna (Spain)

    2016-02-15

    Recently the ATLAS experiment announced a 3 σ excess at the Z-peak consisting of 29 pairs of leptons together with two or more jets, E{sub T}{sup miss} > 225 GeV and HT > 600 GeV, to be compared with 10.6 ± 3.2 expected lepton pairs in the Standard Model. No excess outside the Z-peak was observed. By trying to explain this signal with SUSY we find that only relatively light gluinos, m{sub g} or similar 400 GeV decaying predominantly to Z-boson plus a light gravitino, such that nearly every gluino produces at least one Z-boson in its decay chain, could reproduce the excess. We construct an explicit general gauge mediation model able to reproduce the observed signal overcoming all the experimental limits. Needless to say, more sophisticated models could also reproduce the signal, however, any model would have to exhibit the following features: light gluinos, or heavy particles with a strong production cross section, producing at least one Z-boson in its decay chain. The implications of our findings for the Run II at LHC with the scaling on the Z peak, as well as for the direct search of gluinos and other SUSY particles, are pointed out. (orig.)

  6. Acquisition of peak responding: what is learned?

    Science.gov (United States)

    Balci, Fuat; Gallistel, Charles R; Allen, Brian D; Frank, Krystal M; Gibson, Jacqueline M; Brunner, Daniela

    2009-01-01

    We investigated how the common measures of timing performance behaved in the course of training on the peak procedure in C3H mice. Following fixed interval (FI) pre-training, mice received 16 days of training in the peak procedure. The peak time and spread were derived from the average response rates while the start and stop times and their relative variability were derived from a single-trial analysis. Temporal precision (response spread) appeared to improve in the course of training. This apparent improvement in precision was, however, an averaging artifact; it was mediated by the staggered appearance of timed stops, rather than by the delayed occurrence of start times. Trial-by-trial analysis of the stop times for individual subjects revealed that stops appeared abruptly after three to five sessions and their timing did not change as training was prolonged. Start times and the precision of start and stop times were generally stable throughout training. Our results show that subjects do not gradually learn to time their start or stop of responding. Instead, they learn the duration of the FI, with robust temporal control over the start of the response; the control over the stop of response appears abruptly later.

  7. METing SUSY on the Z peak

    International Nuclear Information System (INIS)

    Barenboim, G.; Bernabeu, J.; Vives, O.; Mitsou, V.A.; Romero, E.

    2016-01-01

    Recently the ATLAS experiment announced a 3 σ excess at the Z-peak consisting of 29 pairs of leptons together with two or more jets, E T miss > 225 GeV and HT > 600 GeV, to be compared with 10.6 ± 3.2 expected lepton pairs in the Standard Model. No excess outside the Z-peak was observed. By trying to explain this signal with SUSY we find that only relatively light gluinos, m g or similar 400 GeV decaying predominantly to Z-boson plus a light gravitino, such that nearly every gluino produces at least one Z-boson in its decay chain, could reproduce the excess. We construct an explicit general gauge mediation model able to reproduce the observed signal overcoming all the experimental limits. Needless to say, more sophisticated models could also reproduce the signal, however, any model would have to exhibit the following features: light gluinos, or heavy particles with a strong production cross section, producing at least one Z-boson in its decay chain. The implications of our findings for the Run II at LHC with the scaling on the Z peak, as well as for the direct search of gluinos and other SUSY particles, are pointed out. (orig.)

  8. The dislocation-internal friction peak γ in tantalum

    International Nuclear Information System (INIS)

    Baur, J.; Benoit, W.; Schultz, H.

    1989-01-01

    Torsion-pendulum measurements were carried out on high-purity single crystal specimens of tantalum, having extremely low oxygen contents ( 2 peak, which appears close to γ is small traces of oxygen are presents. The γ 2 peak was formerly explained as a ''dislocation-enhanced Snoek peak''. The γ peak recovers at the peak temperature, whereas the γ 2 peak is more stable. On the basis of their results, and making use of earlier investigations of Rodrian and Schultz, the authors suggest that γ 2 is modified γ relaxation, related to screw-dislocation segments, stabilized by oxygen-decorated kinks. The stability of the γ 2 peak allows an accurate determination of the activation energy, found to be 1.00 +- 0.03 eV. This value is distinctly lower than the activation energy of the oxygen Snoek effect (1.10 eV) and is related here to the mechanism of ''kink-pair formation'' in screw dislocations, as the original γ peak. The numerical value is compatible with recent values derived from flow-stress measurements. The peak γ 2 shows increasing stability with increasing oxygen content. This is explained by single- and multi-decorated kinks

  9. Individual vision and peak distribution in collective actions

    Science.gov (United States)

    Lu, Peng

    2017-06-01

    People make decisions on whether they should participate as participants or not as free riders in collective actions with heterogeneous visions. Besides of the utility heterogeneity and cost heterogeneity, this work includes and investigates the effect of vision heterogeneity by constructing a decision model, i.e. the revised peak model of participants. In this model, potential participants make decisions under the joint influence of utility, cost, and vision heterogeneities. The outcomes of simulations indicate that vision heterogeneity reduces the values of peaks, and the relative variance of peaks is stable. Under normal distributions of vision heterogeneity and other factors, the peaks of participants are normally distributed as well. Therefore, it is necessary to predict distribution traits of peaks based on distribution traits of related factors such as vision heterogeneity and so on. We predict the distribution of peaks with parameters of both mean and standard deviation, which provides the confident intervals and robust predictions of peaks. Besides, we validate the peak model of via the Yuyuan Incident, a real case in China (2014), and the model works well in explaining the dynamics and predicting the peak of real case.

  10. Statistical analysis of uncertainties of gamma-peak identification and area calculation in particulate air-filter environment radionuclide measurements using the results of a Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) organized intercomparison, Part I: Assessment of reliability and uncertainties of isotope detection and energy precision using artificial spiked test spectra, Part II: Assessment of the true type I error rate and the quality of peak area estimators in relation to type II errors using large numbers of natural spectra

    International Nuclear Information System (INIS)

    Zhang, W.; Zaehringer, M.; Ungar, K.; Hoffman, I.

    2008-01-01

    In this paper, the uncertainties of gamma-ray small peak analysis have been examined. As the intensity of a gamma-ray peak approaches its detection decision limit, derived parameters such as centroid channel energy, peak area, peak area uncertainty, baseline determination, and peak significance are statistically sensitive. The intercomparison exercise organized by the CTBTO provided an excellent opportunity for this to be studied. Near background levels, the false-positive and false-negative peak identification frequencies in artificial test spectra have been compared to statistically predictable limiting values. In addition, naturally occurring radon progeny were used to compare observed variance against nominal uncertainties. The results infer that the applied fit algorithms do not always represent the best estimator. Understanding the statistically predicted peak-finding limit is important for data evaluation and analysis assessment. Furthermore, these results are useful to optimize analytical procedures to achieve the best results

  11. Safety Evaluation Report related to the operation of Comanche Peak Steam Electric Station, Units 1 and 2 (Docket Nos. 50-445 and 50-446). Supplement No. 9

    International Nuclear Information System (INIS)

    1985-03-01

    This supplement addresses TUEC's analyses in support of its request to amend the Comanche Peak Final Safety Analysis Report to eliminate the commitment that coatings inside the reactor Containment Building be qualified for Units 1 and 2. In addition, this supplement provides the results of the staff's evaluation and resolution of 62 technical concerns and allegations in the coatings area for Unit 1. Because of the favorable resolution of the items discussed in this report, the staff concludes for the issues considered herein, that there is reasonable assurance that the facility can be operated by TUEC without endangering the health and safety of the public

  12. Tennis Play Intensity Distribution and Relation with Aerobic Fitness in Competitive Players.

    Directory of Open Access Journals (Sweden)

    Ernest Baiget

    Full Text Available The aims of this study were (i to describe the relative intensity of simulated tennis play based on the cumulative time spent in three metabolic intensity zones, and (ii to determine the relationships between this play intensity distribution and the aerobic fitness of a group of competitive players. 20 male players of advanced to elite level (ITN performed an incremental on-court specific endurance tennis test to exhaustion to determine maximal oxygen uptake (VO2max and the first and second ventilatory thresholds (VT1, VT2. Ventilatory and gas exchange parameters were monitored using a telemetric portable gas analyser (K4 b2, Cosmed, Rome, Italy. Two weeks later the participants played a simulated tennis set against an opponent of similar level. Intensity zones (1: low, 2: moderate, and 3: high were delimited by the individual VO2 values corresponding to VT1 and VT2, and expressed as percentage of maximum VO2 and heart rate. When expressed relative to VO2max, percentage of playing time in zone 1 (77 ± 25% was significantly higher (p < 0.001 than in zone 2 (20 ± 21% and zone 3 (3 ± 5%. Moderate to high positive correlations were found between VT1, VT2 and VO2max, and the percentage of playing time spent in zone 1 (r = 0.68-0.75, as well as low to high inverse correlations between the metabolic variables and the percentage of time spent in zone 2 and 3 (r = -0.49-0.75. Players with better aerobic fitness play at relatively lower intensities. We conclude that players spent more than 75% of the time in their low-intensity zone, with less than 25% of the time spent at moderate to high intensities. Aerobic fitness appears to determine the metabolic intensity that players can sustain throughout the game.

  13. Establishment of peak bone mass.

    Science.gov (United States)

    Mora, Stefano; Gilsanz, Vicente

    2003-03-01

    Among the main areas of progress in osteoporosis research during the last decade or so are the general recognition that this condition, which is the cause of so much pain in the elderly population, has its antecedents in childhood and the identification of the structural basis accounting for much of the differences in bone strength among humans. Nevertheless, current understanding of the bone mineral accrual process is far from complete. The search for genes that regulate bone mass acquisition is ongoing, and current results are not sufficient to identify subjects at risk. However, there is solid evidence that BMD measurements can be helpful for the selection of subjects that presumably would benefit from preventive interventions. The questions regarding the type of preventive interventions, their magnitude, and duration remain unanswered. Carefully designed controlled trials are needed. Nevertheless, previous experience indicates that weight-bearing activity and possibly calcium supplements are beneficial if they are begun during childhood and preferably before the onset of puberty. Modification of unhealthy lifestyles and increments in exercise or calcium assumption are logical interventions that should be implemented to improve bone mass gains in all children and adolescents who are at risk of failing to achieve an optimal peak bone mass.

  14. Reactor power peaking information display

    International Nuclear Information System (INIS)

    Book, T.L.; Kochendarfer, R.A.

    1986-01-01

    This patent describes a system for monitoring operating conditions within a nuclear reactor. The system consists of a method for measuring the operating parameters within the nuclear reactor, including the position of axial power shaping rods and regulating control rod. It also includes a method for determining from the operating parameters the operating limits before a power peaking condition exists within the nuclear reactor, and a method for displaying the operating limits which consists of a visual display permitting the continuous monitoring of the operating conditions within the nuclear reactor as a graph of the shaping rod position vs the regulating rod position having a permissible area and a restricted area. The permissible area is further divided into a recommended operating area for steady state operation and a cursor located on the graph to indicate the present operating condition of the nuclear reactor to allow an operator to view any need for corrective action based on the movement of the cursor out of the recommended operating area and to take any corrective transient action within the permissible area

  15. FHWA operations support : port peak pricing program evaluation

    Science.gov (United States)

    2009-01-01

    This report evaluates the applicability, Federal policy implications, and possible public and private sector roles related to peak pricing strategies at ports and intermodal facilities in the U.S. A number of ports and intermodal terminals are consid...

  16. National surveillance of pandemic influenza A(H1N1) infection-related admissions to intensive care units during the 2009-10 winter peak in Denmark: two complementary approaches

    DEFF Research Database (Denmark)

    Gubbels, S; Perner, A; Valentiner-Branth, Palle

    2010-01-01

    close contact with a laboratory-confirmed case. Aggregate numbers of cases were reported weekly: during weeks 48-51 (the peak), reporting was daily. The case-based reports contained demographic and clinical information. The aggregate surveillance registered 93 new cases, the case-based surveillance 61......Surveillance of 2009 pandemic influenza A(H1N1) in Denmark was enhanced during the 2009–10 winter season with a system monitoring the burden of the pandemic on intensive care units (ICUs), in order to inform policymakers and detect shortages in ICUs in a timely manner. Between week 46 of 2009...... and week 11 of 2010, all 36 relevant Danish ICUs reported in two ways: aggregate data were reported online and case-based data on paper. Cases to be reported were defined as patients admitted to an ICU with laboratory-confirmed 2009 pandemic influenza A(H1N1) infection or clinically suspected illness after...

  17. Computation of peak discharge at culverts

    Science.gov (United States)

    Carter, Rolland William

    1957-01-01

    Methods for computing peak flood flow through culverts on the basis of a field survey of highwater marks and culvert geometry are presented. These methods are derived from investigations of culvert flow as reported in the literature and on extensive laboratory studies of culvert flow. For convenience in computation, culvert flow has been classified into six types, according to the location of the control section and the relative heights of the head-water and tail-water levels. The type of flow which occurred at any site can be determined from the field data and the criteria given in this report. A discharge equation has been developed for each flow type by combining the energy and continuity equations for the distance between an approach section upstream from the culvert and a terminal section within the culvert barrel. The discharge coefficient applicable to each flow type is listed for the more common entrance geometries. Procedures for computing peak discharge through culverts are outlined in detail for each of the six flow types.

  18. Monitoring device for local power peaking coefficient

    International Nuclear Information System (INIS)

    Mitsuhashi, Ishi

    1987-01-01

    Purpose: To monitor the local power peaking coefficients obtained by the method not depending on the combination of fuel types. Method: A plurality of representative values for the local power distribution determined by the nuclear constant calculation for one fuel assembly are memorized regarding each of the burn-up degree and the void coefficient on every positions and fuel types in fuel rod assemblies. While on the other hand, the representative values for the local power distribution as described above are compensated by a compensation coefficient considering the effect of adjacent segments and a control rod compensation coefficient considering the effect due to the control rod insertion relative to the just-mentioned compensation coefficient. Then, the maximum value among them is selected to determine the local power peaking coefficient at each of the times and each of the segments, which is monitored. According to this system, the calculation and the working required for the fitting work depending on the combination of fuel types are no more required at all to facilitate the maintenance as well. (Horiuchi, T.)

  19. Absolute and relative reliability of acute effects of aerobic exercise on executive function in seniors.

    Science.gov (United States)

    Donath, Lars; Ludyga, Sebastian; Hammes, Daniel; Rossmeissl, Anja; Andergassen, Nadin; Zahner, Lukas; Faude, Oliver

    2017-10-25

    Aging is accompanied by a decline of executive function. Aerobic exercise training induces moderate improvements of cognitive domains (i.e., attention, processing, executive function, memory) in seniors. Most conclusive data are obtained from studies with dementia or cognitive impairment. Confident detection of exercise training effects requires adequate between-day reliability and low day-to-day variability obtained from acute studies, respectively. These absolute and relative reliability measures have not yet been examined for a single aerobic training session in seniors. Twenty-two healthy and physically active seniors (age: 69 ± 3 y, BMI: 24.8 ± 2.2, VO 2peak : 32 ± 6 mL/kg/bodyweight) were enrolled in this randomized controlled cross-over study. A repeated between-day comparison [i.e., day 1 (habituation) vs. day 2 & day 2 vs. day 3] of executive function testing (Eriksen-Flanker-Test, Stroop-Color-Test, Digit-Span, Five-Point-Test) before and after aerobic cycling exercise at 70% of the heart rate reserve [0.7 × (HR max - HR rest )] was conducted. Reliability measures were calculated for pre, post and change scores. Large between-day differences between day 1 and 2 were found for reaction times (Flanker- and Stroop Color testing) and completed figures (Five-Point test) at pre and post testing (0.002 seniors can be presumed.

  20. Passive radio frequency peak power multiplier

    Science.gov (United States)

    Farkas, Zoltan D.; Wilson, Perry B.

    1977-01-01

    Peak power multiplication of a radio frequency source by simultaneous charging of two high-Q resonant microwave cavities by applying the source output through a directional coupler to the cavities and then reversing the phase of the source power to the coupler, thereby permitting the power in the cavities to simultaneously discharge through the coupler to the load in combination with power from the source to apply a peak power to the load that is a multiplication of the source peak power.

  1. Practical load management - Peak shaving using photovoltaics

    International Nuclear Information System (INIS)

    Berger, W.

    2009-01-01

    This article takes a look at how photovoltaic (PV) power generation can be used in a practical way to meet peak demands for electricity. Advice is provided on how photovoltaics can provide peak load 'shaving' through the correlation between its production and the peak loads encountered during the day. The situation regarding feed-in tariffs in Italy is discussed, as are further examples of installations in Germany and Austria. Further, an initiative of the American Southern California Edison utility is discussed which foresees the installation of large PV plant on the roofs of commercial premises to provide local generation of peak energy and thus relieve demands on their power transportation network.

  2. The geomorphic structure of the runoff peak

    Directory of Open Access Journals (Sweden)

    R. Rigon

    2011-06-01

    Full Text Available This paper develops a theoretical framework to investigate the core dependence of peak flows on the geomorphic properties of river basins. Based on the theory of transport by travel times, and simple hydrodynamic characterization of floods, this new framework invokes the linearity and invariance of the hydrologic response to provide analytical and semi-analytical expressions for peak flow, time to peak, and area contributing to the peak runoff. These results are obtained for the case of constant-intensity hyetograph using the Intensity-Duration-Frequency (IDF curves to estimate extreme flow values as a function of the rainfall return period. Results show that, with constant-intensity hyetographs, the time-to-peak is greater than rainfall duration and usually shorter than the basin concentration time. Moreover, the critical storm duration is shown to be independent of rainfall return period as well as the area contributing to the flow peak. The same results are found when the effects of hydrodynamic dispersion are accounted for. Further, it is shown that, when the effects of hydrodynamic dispersion are negligible, the basin area contributing to the peak discharge does not depend on the channel velocity, but is a geomorphic propriety of the basin. As an example this framework is applied to three watersheds. In particular, the runoff peak, the critical rainfall durations and the time to peak are calculated for all links within a network to assess how they increase with basin area.

  3. [A peak recognition algorithm designed for chromatographic peaks of transformer oil].

    Science.gov (United States)

    Ou, Linjun; Cao, Jian

    2014-09-01

    In the field of the chromatographic peak identification of the transformer oil, the traditional first-order derivative requires slope threshold to achieve peak identification. In terms of its shortcomings of low automation and easy distortion, the first-order derivative method was improved by applying the moving average iterative method and the normalized analysis techniques to identify the peaks. Accurate identification of the chromatographic peaks was realized through using multiple iterations of the moving average of signal curves and square wave curves to determine the optimal value of the normalized peak identification parameters, combined with the absolute peak retention times and peak window. The experimental results show that this algorithm can accurately identify the peaks and is not sensitive to the noise, the chromatographic peak width or the peak shape changes. It has strong adaptability to meet the on-site requirements of online monitoring devices of dissolved gases in transformer oil.

  4. Maintained peak leg and pulmonary VO2 despite substantial reduction in muscle mitochondrial capacity

    DEFF Research Database (Denmark)

    Boushel, Robert; Gnaiger, E.; Larsen, F. J.

    2015-01-01

    We recently reported the circulatory and muscle oxidative capacities of the arm after prolonged low-intensity skiing in the arctic (Boushel et al., 2014). In the present study, leg VO2 was measured by the Fick method during leg cycling while muscle mitochondrial capacity was examined on a biopsy ...... at a higher mitochondrial p50. These findings support the concept that muscle mitochondrial respiration is submaximal at VO2max , and that mitochondrial volume can be downregulated by chronic energy demand....

  5. Peak load pricing lowers generation costs

    International Nuclear Information System (INIS)

    Lande, R.H.

    1980-01-01

    Before a utility implements peak load pricing for different classes of consumers, the costs and the benefits should be compared. The methodology described enables a utility to determine whether peak load pricing should be introduced for specific users. Cost-benefit analyses for domestic consumers and commercial/industrial consumers, showing break-even points are presented. (author)

  6. Peak Shaving Considering Streamflow Uncertainties | Iwuagwu ...

    African Journals Online (AJOL)

    The main thrust of this paper is peak shaving with a Stochastic hydro model. In peak sharing, the amount of hydro energy scheduled may be a minimum but it serves to replace less efficient thermal units. The sample system is die Kainji hydro plant and the thermal units of the National Electric Power Authority. The random ...

  7. The peak in neutron powder diffraction

    International Nuclear Information System (INIS)

    Laar, B. van; Yelon, W.B.

    1984-01-01

    For the application of Rietveld profile analysis to neutron powder diffraction data a precise knowledge of the peak profile, in both shape and position, is required. The method now in use employs a Gaussian shaped profile with a semi-empirical asymmetry correction for low-angle peaks. The integrated intensity is taken to be proportional to the classical Lorentz factor calculated for the X-ray case. In this paper an exact expression is given for the peak profile based upon the geometrical dimensions of the diffractometer. It is shown that the asymmetry of observed peaks is well reproduced by this expression. The angular displacement of the experimental profile with respect to the nominal Bragg angle value is larger than expected. Values for the correction to the classical Lorentz factor for the integrated intensity are given. The exact peak profile expression has been incorporated into a Rietveld profile analysis refinement program. (Auth.)

  8. Peak tree: a new tool for multiscale hierarchical representation and peak detection of mass spectrometry data.

    Science.gov (United States)

    Zhang, Peng; Li, Houqiang; Wang, Honghui; Wong, Stephen T C; Zhou, Xiaobo

    2011-01-01

    Peak detection is one of the most important steps in mass spectrometry (MS) analysis. However, the detection result is greatly affected by severe spectrum variations. Unfortunately, most current peak detection methods are neither flexible enough to revise false detection results nor robust enough to resist spectrum variations. To improve flexibility, we introduce peak tree to represent the peak information in MS spectra. Each tree node is a peak judgment on a range of scales, and each tree decomposition, as a set of nodes, is a candidate peak detection result. To improve robustness, we combine peak detection and common peak alignment into a closed-loop framework, which finds the optimal decomposition via both peak intensity and common peak information. The common peak information is derived and loopily refined from the density clustering of the latest peak detection result. Finally, we present an improved ant colony optimization biomarker selection method to build a whole MS analysis system. Experiment shows that our peak detection method can better resist spectrum variations and provide higher sensitivity and lower false detection rates than conventional methods. The benefits from our peak-tree-based system for MS disease analysis are also proved on real SELDI data.

  9. Aerobic capacity explains physical functioning and participation in patients with multiple sclerosis-related fatigue

    OpenAIRE

    Emma Rosalie Driehuis; Lizanne Eva van den Akker; Vincent de Groot; Heleen Beckerman

    2018-01-01

    Objective: To investigate whether aerobic capacity explains the level of self-reported physical activity, physical functioning, and participation and autonomy in daily living in persons with multiple sclerosis-related fatigue. Design: A cross-sectional study. Patients: Sixty-two participants with multiple sclerosis-related fatigue. Methods: Aerobic capacity was measured with a leg ergometer and was expressed as maximal oxygen uptake (VO2max, in ...

  10. Fast clustering using adaptive density peak detection.

    Science.gov (United States)

    Wang, Xiao-Feng; Xu, Yifan

    2017-12-01

    Common limitations of clustering methods include the slow algorithm convergence, the instability of the pre-specification on a number of intrinsic parameters, and the lack of robustness to outliers. A recent clustering approach proposed a fast search algorithm of cluster centers based on their local densities. However, the selection of the key intrinsic parameters in the algorithm was not systematically investigated. It is relatively difficult to estimate the "optimal" parameters since the original definition of the local density in the algorithm is based on a truncated counting measure. In this paper, we propose a clustering procedure with adaptive density peak detection, where the local density is estimated through the nonparametric multivariate kernel estimation. The model parameter is then able to be calculated from the equations with statistical theoretical justification. We also develop an automatic cluster centroid selection method through maximizing an average silhouette index. The advantage and flexibility of the proposed method are demonstrated through simulation studies and the analysis of a few benchmark gene expression data sets. The method only needs to perform in one single step without any iteration and thus is fast and has a great potential to apply on big data analysis. A user-friendly R package ADPclust is developed for public use.

  11. Isotope resolution of the iron peak

    International Nuclear Information System (INIS)

    Henke, R.P.; Benton, E.V.

    1977-01-01

    A stack of Lexan detectors from the Apollo 17 mission has been analyzed to obtain Z measurements of sufficient accuracy to resolve the iron peak into its isotopic components. Within this distribution several peaks are present. With the centrally located, most populated peak assumed to be 56 Fe, the measurements imply that the abundances of 54 Fe and 58 Fe are appreciable fractions of the 56 Fe abundance. This result is in agreement with those of Webber et al. and Siegman et al. but in disagreement with the predictions of Tsao et al. (Auth.)

  12. Peak load arrangements : Assessment of Nordel guidelines

    Energy Technology Data Exchange (ETDEWEB)

    2009-07-01

    Two Nordic countries, Sweden and Finland, have legislation that empowers the TSO to acquire designated peak load resources to mitigate the risk for shortage situations during the winter. In Denmark, the system operator procures resources to maintain a satisfactory level of security of supply. In Norway the TSO has set up a Regulation Power Option Market (RKOM) to secure a satisfactory level of operational reserves at all times, also in winter with high load demand. Only the arrangements in Finland and Sweden fall under the heading of Peak Load Arrangements defined in Nordel Guidelines. NordREG has been invited by the Electricity Market Group (EMG) to evaluate Nordel's proposal for 'Guidelines for transitional Peak Load Arrangements'. The EMG has also financed a study made by EC Group to support NordREG in the evaluation of the proposal. The study has been taken into account in NordREG's evaluation. In parallel to the EMG task, the Swedish regulator, the Energy Markets Inspectorate, has been given the task by the Swedish government to investigate a long term solution of the peak load issue. The Swedish and Finnish TSOs have together with Nord Pool Spot worked on finding a harmonized solution for activation of the peak load reserves in the market. An agreement accepted by the relevant authorities was reached in early January 2009, and the arrangement has been implemented since 19th January 2009. NordREG views that the proposed Nordel guidelines have served as a starting point for the presently agreed procedure. However, NordREG does not see any need to further develop the Nordel guidelines for peak load arrangements. NordREG agrees with Nordel that the market should be designed to solve peak load problems through proper incentives to market players. NordREG presumes that the relevant authorities in each country will take decisions on the need for any peak load arrangement to ensure security of supply. NordREG proposes that such decisions should be

  13. Automated Peak Picking and Peak Integration in Macromolecular NMR Spectra Using AUTOPSY

    Science.gov (United States)

    Koradi, Reto; Billeter, Martin; Engeli, Max; Güntert, Peter; Wüthrich, Kurt

    1998-12-01

    A new approach for automated peak picking of multidimensional protein NMR spectra with strong overlap is introduced, which makes use of the program AUTOPSY (automatedpeak picking for NMRspectroscopy). The main elements of this program are a novel function for local noise level calculation, the use of symmetry considerations, and the use of lineshapes extracted from well-separated peaks for resolving groups of strongly overlapping peaks. The algorithm generates peak lists with precise chemical shift and integral intensities, and a reliability measure for the recognition of each peak. The results of automated peak picking of NOESY spectra with AUTOPSY were tested in combination with the combined automated NOESY cross peak assignment and structure calculation routine NOAH implemented in the program DYANA. The quality of the resulting structures was found to be comparable with those from corresponding data obtained with manual peak picking.

  14. Bayesian Peak Picking for NMR Spectra

    KAUST Repository

    Cheng, Yichen

    2014-02-01

    Protein structure determination is a very important topic in structural genomics, which helps people to understand varieties of biological functions such as protein-protein interactions, protein–DNA interactions and so on. Nowadays, nuclear magnetic resonance (NMR) has often been used to determine the three-dimensional structures of protein in vivo. This study aims to automate the peak picking step, the most important and tricky step in NMR structure determination. We propose to model the NMR spectrum by a mixture of bivariate Gaussian densities and use the stochastic approximation Monte Carlo algorithm as the computational tool to solve the problem. Under the Bayesian framework, the peak picking problem is casted as a variable selection problem. The proposed method can automatically distinguish true peaks from false ones without preprocessing the data. To the best of our knowledge, this is the first effort in the literature that tackles the peak picking problem for NMR spectrum data using Bayesian method.

  15. Peak-Seeking Control for Trim Optimization

    Data.gov (United States)

    National Aeronautics and Space Administration — Innovators have developed a peak-seeking algorithm that can reduce drag and improve performance and fuel efficiency by optimizing aircraft trim in real time. The...

  16. The origin of a peak in the reststrahlen region of SiC

    International Nuclear Information System (INIS)

    Engelbrecht, J.A.A.; Rooyen, I.J. van; Henry, A.; Janzén, E.; Olivier, E.J.

    2012-01-01

    A peak in the reststrahlen region of SiC is analyzed in order to establish the origin of this peak. The peak can be associated with a thin damaged layer on the SiC wafers, and a relation is found between surface roughness and the height of this peak, by modeling the damaged layer as an additional layer when simulating the reflectivity from the wafers.

  17. The origin of a peak in the reststrahlen region of SiC

    Energy Technology Data Exchange (ETDEWEB)

    Engelbrecht, J.A.A., E-mail: Japie.Engelbrecht@nmmu.ac.za [Physics Department, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth 6031 (South Africa); Rooyen, I.J. van [Physics Department, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth 6031 (South Africa); Henry, A.; Janzen, E. [Department of Physics, Chemistry and Biology, Linkoeping University, SE-581 83 Linkoeping (Sweden); Olivier, E.J. [Physics Department, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth 6031 (South Africa)

    2012-05-15

    A peak in the reststrahlen region of SiC is analyzed in order to establish the origin of this peak. The peak can be associated with a thin damaged layer on the SiC wafers, and a relation is found between surface roughness and the height of this peak, by modeling the damaged layer as an additional layer when simulating the reflectivity from the wafers.

  18. T(peak)T(end) interval in long QT syndrome

    DEFF Research Database (Denmark)

    Kanters, Jørgen Kim; Haarmark, Christian; Vedel-Larsen, Esben

    2008-01-01

    BACKGROUND: The T(peak)T(end) (T(p)T(e)) interval is believed to reflect the transmural dispersion of repolarization. Accordingly, it should be a risk factor in long QT syndrome (LQTS). The aim of the study was to determine the effect of genotype on T(p)T(e) interval and test whether it was relat...

  19. Knowledge, attitude and practice of nurses toward peak expiratory ...

    African Journals Online (AJOL)

    Background: Peak expiratory flow meter (PEFM) is an easy to use, relatively cheap device that can be used for guiding management of bronchial asthma by the patients at home according to a preset plan by health care workers. Objective: The aim of the study is to reveal the extent of knowledge and perception of nurses ...

  20. quasi hyperrigidity and weak peak points for non-commutative ...

    Indian Academy of Sciences (India)

    7

    Abstract. In this article, we introduce the notions of weak boundary repre- sentation, quasi hyperrigidity and weak peak points in the non-commutative setting for operator systems in C∗-algebras. An analogue of Saskin's theorem relating quasi hyperrigidity and weak Choquet boundary for particular classes of C∗-algebras is ...

  1. Limitation of peak fitting and peak shape methods for determination of activation energy of thermoluminescence glow peaks

    CERN Document Server

    Sunta, C M; Piters, T M; Watanabe, S

    1999-01-01

    This paper shows the limitation of general order peak fitting and peak shape methods for determining the activation energy of the thermoluminescence glow peaks in the cases in which retrapping probability is much higher than the recombination probability and the traps are filled up to near saturation level. Right values can be obtained when the trap occupancy is reduced by using small doses or by post-irradiation partial bleaching. This limitation in the application of these methods has not been indicated earlier. In view of the unknown nature of kinetics in the experimental samples, it is recommended that these methods of activation energy determination should be applied only at doses well below the saturation dose.

  2. Gnevyshev peaks in solar radio emissions at different freque