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1.
Protein recovery by continuous flotation 总被引:2,自引:0,他引:2
Summary Bovine serum albumin (BSA) was recovered from aqueous solutions by foam flotation. The protein concentrations in foam liquid C
S, in feed C
Pand in residue C
Rwere determined. The protein enrichment C
S/CPand the separation C
S/CRas well as the protein fraction in the foam liquid % BSA and foam liquid volume flow were determined as functions of the medium properties, operational conditions, and equipment parameters as well as concentrations of solid particles. At low protein concentrations in feed (e.g., C
P=40 mg · l-1), and at 40° C, high performance was attained (C
X=2,000 mg · l-1, C
R=4.4 mg · l-1, C
S/CP=50, C
S/CR=450, 90% BSA. Continuous foam flotation is an efficient procedure for the recovery of low concentrations of proteins from liquid cultures.Abbreviations BSA
bovine serum albumine
-
C
P
protein concentration in feed (mg · l-1)
-
C
R
protein concentration in residue (mg · l-1)
-
C
S
protein concentration in foam liquid (mg · l-1)
-
C
S/CR
protein separation (-)
-
C
S/CP
protein enrichment (-)
-
V
P
feed rate (ml · min-1)
-
V
R
residue flow rate (ml · min-1)
-
V
S
foam liquid volume flow (ml · min-1)
-
N
number of theoretical stages in an ideal cascade (-)
-
temperature (° C)
-
mean residence time (min) 相似文献
2.
Carlo Capelli Guglielmo Antonutto Paola Zamparo Massimo Girardis Pietro Enrico di Prampero 《European journal of applied physiology and occupational physiology》1993,66(3):189-195
The mechanical power (Wtot, W·kg–1) developed during ten revolutions of all-out periods of cycle ergometer exercise (4–9 s) was measured every 5–6 min in six subjects from rest or from a baseline of constant aerobic exercise [50%–80% of maximal oxygen uptake (VO2max)] of 20–40 min duration. The oxygen uptake [VO2 (W·kg–1, 1 ml O2 = 20.9 J)] and venous blood lactate concentration ([la]b, mM) were also measured every 15 s and 2 min, respectively. During the first all-out period, Wtot decreased linearly with the intensity of the priming exercise (Wtot = 11.9–0.25·VO2). After the first all-out period (i greater than 5–6 min), and if the exercise intensity was less than 60% VO2max, Wtot, VO2 and [la]b remained constant until the end of the exercise. For exercise intensities greater than 60% VO2max, VO2 and [la]b showed continuous upward drifts and Wtot continued decreasing. Under these conditions, the rate of decrease of Wtot was linearly related to the rate of increase of V [(d Wtot/dt) (W·kg–1·s–1) = 5.0·10–5 –0.20·(d VO2/dt) (W·kg–1·s–1)] and this was linearly related to the rate of increase of [la]b [(d VO2/dt) (W·kg–1·s–1) = 2.310–4 + 5.910–5·(d [la]b/dt) (mM·s–1)]. These findings would suggest that the decrease of Wtot during the first all-out period was due to the decay of phosphocreatine concentration in the exercising muscles occurring at the onset of exercise and the slow drifts of VO2 (upwards) and of Wtot (downwards) during intense exercise at constant Wtot could be attributed to the continuous accumulation of lactate in the blood (and in the working muscles). 相似文献
3.
Simon Green B. Tex Dawson 《European journal of applied physiology and occupational physiology》1995,70(4):351-359
The regression of oxygen uptake (O2) on power output and the O2 demand predicted for suprapeak oxygen uptake (O2peak) exercise (power output = 432 W) were compared in ten male cyclists [C, mean O2peak = 67.9 (SD 4.2) ml · kg–1 · min–1] and nine active, yet untrained men [UT, mean O2peak = 54.1 (SD 6.5) ml · kg–1 · min–1]. The O2-power regression was determined using a continuous incremental cycle test (CON4), performed twice, which comprised several 4-min exercise periods progressing in intensity from approximately 40%–85% O2peak. Minute ventilation (E), heart rate (HR), respiratory exchange ratio (R), blood lactate concentration ([1a–]b) and rectal temperature (T
re) were measured at rest and during CON4. The slope of the O2-power regression was greater (P 0.05) in C [12.4 (SD 0.7) ml · min–1. W–1] compared to UT [11.7 (SD 0.4) ml · min–1 W–1]; as a result, the O2 demand (at 432 W) was also higher (P 0.05) in C [5.97 (SD 0.23) l · min–1] than UT [5.70 (SD 0.15) 1 · min–1]. ExerciseR and [la–]b were lower (P 0.05) in C .in comparison to UT at all power outputs, whereas E and HR were relatively lower (P 0.05) in C at power outputs approximating 180 W, 220 W and 270 W. Differences in fat metabolism estimated over the first three power outputs accounted for approximately 19% of the difference in O2-power slopes between the groups and up to 46% of the difference in O2 at a given intensity. Although the O2-power regressions were linear for C [r = 0.997 (SD 0.001)] and UT [r = 0.997 (SD 0.001)], the O2-power slope was higher at power outputs at or above the lactate threshold (13.2 ml · min–1 · W–1 than at lower intensities (11.6 ml · min–1 · W–1) in C, an effect which was less profound in UT. As a result, the exclusion of O2 at the highest power outputs completely abolished the difference in O2-power slopes between C and UT. Thus, the relatively higher O2 during incremental exercise in C can be almost entirely attributed to the higher O2 cost of cycling at higher power outputs. In addition, the presence of non-linear responses in O2 at higher intensities also confirms the invalidity of describing the O2 response across a wide range of power outputs using a linear function, and challenges the validity of predicting the O2 demand of more intense exercise by a linear extrapolation of this same function. 相似文献
4.
Steve F. Perry Serge Thomas 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1991,161(5):489-497
Summary An extracorporeal circulation of rainbow trout (Oncorhynchus mykiss) was utilized to continuously monitor the rapid and progressive effects of endogenous or exogenous catecholamines on blood respiratory/acid-base status, and to provide in vivo evidence for adrenergic retention of carbon dioxide (CO2) in fish blood (cf. Wood and Perry 1985). Exposure of fish to severe aquatic hypoxia (final P
wO2=40–60 torr; reached within 10–20 min) elicited an initial respiratory alkalosis resulting from hypoxia-induced hyperventilation. However, at a critical arterial oxygen tension (P
aO2) between 15 and 25 torr, fish became agitated for approximately 5 s and a marked (0.2–0.4 pH unit) but transient arterial blood acidosis ensued. This response is characteristic of abrupt catecholamine mobilization into the circulation and subsequent adrenergic activation of red blood cell (RBC) Na+/H+ exchange (Fievet et al. 1987). Within approximately 1–2 min after the activation of RBC Na+/H+ exchange by endogenous catecholamines, there was a significant rise in arterial PCO2 (P
aCO2) whereas arterial PO2 was unaltered; the elevation of P
aCO2 could not be explained by changes in gill ventilation. Pre-treatment of fish with the -adrenoceptor antagonist phentolamine did not prevent the apparent catecholamine-mediated increase of P
aCO2. Conversely, pre-treatment with the -adrenoceptor antagonist sotalol abolished both the activation of the RBC Na+/H+ antiporter and the associated rise in P
aCO2, suggesting a causal relationship between the stimulation of RBC Na+/H+ exchange and the elevation of P
aCO2. To more clearly establish that elevation of plasma catecholamine levels during severe hypoxia was indeed responsible for causing the elevation of P
aCO2, fish were exposed to moderate hypoxia (final P
wO2=60–80 torr) and then injected intraarterially with a bolus of adrenaline to elicit an estimated circulating level of 400 nmol·l-1 immediately after the injection. This protocol activated RBC Na+/H+ exchange as indicated by abrupt changes in arterial pH (pHa). In all fish examined, P
aCO2 increased after injection of exogenous adrenaline. The effects on P
aO2 were inconsistent, although a reduction in this variable was the most frequent response. Gill ventilation frequency and amplitude were unaffected by exogenous adrenaline. Therefore, it is unlikely that ventilatory changes contributed to the consistently observed rise in P
aCO2. Pretreatment of fish with sotalol did not alter the ventilatory response to adrenaline injection but did prevent the stimulation of RBC Na+/H+ exchange and the accompanying increases and decreases in P
aCO2 and P
aO2, respectively. These results suggest that adrenergic elevation of P
aCO2, in addition to the frequently observed reduction of P
aO2 are linked to activation of RBC Na+/H+ exchange. The physiological significance and the potential mechanisms underlying the changes in blood respiratory status after addition of endogenous or exogenous catecholamines to the circulation of hypoxic rainbow trout are discussed.Abbreviations
P
aCO2
arterial carbon dioxide tension
-
P
aO2
arterial oxygen tension
-
P
da
dorsal aortic pressure
-
pHa
arterial pH
-
P
wO2
water oxygen tension
-
RBC
red blood cell
-
V
f
breathing frequency 相似文献
5.
Continuous chemotrophic growth and respiration of Chromatiaceae species at low oxygen concentrations 总被引:2,自引:0,他引:2
Endogenous and maximum respiration rates of nine purple sulfur bacterial strains were determined. Endogenous rates were below 10 nmol O2 · (mg protein · min)-1 for sulfur-free cells and 15–35 nmol O2 · (mg protein · min)-1 for cells containg intracellular sulfur globules. With sulfide as electron-donating substrate respiration rates were considerably higher than with thiosulfate. Maximum respiration rates of Thiocystis violacea 2711 and Thiorhodovibrio winogradskyi SSP1 (254.8 and 264.2 nmol O2 · (mg protein · min)-1, respectively) are similar to those of aerobic bacteria. Biphasic respiration curves were obtained for sulfur-free cells of Thiocystis violacea 2711 and Chromatium vinosum 2811. In Thiocystis violacea the rapid and incomplete oxidation of thiosulfate was five times faster than the oxidation of stored sulfur. A high affinity of the respiratoty system for oxygen (K
m
=0.3–0.9 M O2, V
max=260 nmol O2 · (mg protein · min)-1 with sulfide as substrate, K
m
=0.6–2.4 M O2, V
max=14–40 nmol O2 · (mg protein · min)-1 with thiosulfate as substrate), for sulfide (K
m
=0.47 M, V
max=650 nmol H2S · (mg protein × min)-1, and for thiosulfate (K
m
=5–6 M, V
max =24–72 nmol S2O
3
2-
· (mg protein · min)-1 was obtained for different strains. Respiration of Thiocystis violacea was inhibited by very low concentrations of NaCN (K
i
=1.7 M) while CO concentrations of up to 300 M were not inhibitory. The capacity for chemotrophic growth of six species was studied in continuous culture at oxygen concentrations of 11 to 67 M. Thiocystis violacea 2711, Amoebobacter roseus 6611, Thiocapsa roseopersicina 6311 and Thiorhodovibrio winogradskyi SSP1 were able to grow chemotrophically with thiosulfate/acetate or sulfide/acetate. Chromatium vinosum 2811 and Amoebobacter purpureus ML1 failed to grow under these conditions. During shift from phototrophic to chemotrophic conditions intracellular sulfur and carbohydrate accumulated transiently inside the cells. During chemotrophic growth bacteriochlorophyll a was below the detection limit. 相似文献
6.
H. Benoit F. Costes L. Feasson J. R. Lacour F. Roche C. Denis A. Geyssant J. C. Barthélémy 《European journal of applied physiology and occupational physiology》1997,76(3):260-263
There is a growing need to measure arterial oxygen saturation with a non-invasive method during heavy exercise under severe
hypoxic conditions. Although the accuracy of pulse oximetry has been challenged by several authors, it has not been done under
extreme conditions. The purpose of this study was to evaluate the accuracy of a pulse oximeter (Satlite, Datex, Finland) during
exercise under hypoxic conditions where arterial oxygen saturation was below 75%, simulating exercise at extreme altitude.
Ten healthy non-smoking men performed two exercise studies of 30 min under normoxia and under hypoxia on two consecutive days.
The exercise intensity was 80% of maximal O2 consumption of O2max. Arterial oxygen saturation measured by pulse oximetry was corrected (S
pO2[corr]) according to previously published equations and was compared to arterial oxygen saturation (S
aO2) in blood samples taken simultaneously from the radial artery. Reference arterial saturation values ranged from 57.2 to 97.6%
for the whole data set. This data set was split according to low (S
aO2 ≤ 75%) and high (S
aO2 > 75%) S
aO2 values. The error of pulse oximetry (S
pO2[corr]− S
aO2) was 2.05 (0.87)% [mean (SD)] and 1.80 (1.81)% for high and low S
aO2 values, respectively. S
pO2[corr] and S
aO2 were highly correlated (r = 0.93, SEE = 1.8) for low values. During high-intensity constant workload under severe hypoxic conditions, once corrected,
pulse oximetry provides an estimate of S
aO2 with a mean error of 2%. Thus, the correction previously described for S
pO2 values above 75% saturation applies also to S
pO2 values in the range of 57–75% during exercise under hypoxic conditions.
Accepted: 27 February 1997 相似文献
7.
E. Król 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1994,164(6):503-507
Body temperature and oxygen consumption were measured in the eastern hedgehog,Erinaceus concolor Martin 1838, during summer at ambient temperatures (T
a) between-6.0 and 35.6°C.E. concolor has a relatively low basal metabolic rate (0.422 ml O2·g-1·h-1), amounting to 80% of that predicted from its body mass (822.7 g). Between 26.5 and 1.2°C, the resting metabolic rate increases with decreasing ambient temperature according to the equation: RMR=1.980-0.057T
a. The minimal heat transfer coefficient (0.057 ml O2·g-1·h-1·°C-1) is higher than expected in other eutherian mammals, which may result from partial conversion of hair into spines. At lower ambient temperature (from-4.6 to-6.0° C) there is a drop in body temperature (from 35.2 to 31.4° C) and a decrease in oxygen consumption (1.530 ml O2·g-1·h-1) even though the potential thermoregulation capabilities of this species are significantly higher. This is evidenced by the high maximum noradrenaline-induced non-shivering thermogenesis (2.370 ml O2·g-1·h-1), amounting to 124% of the value predicted. The active metabolic rate at ambient temperatures between 31.0 and 14.5° C averages 1.064 ml O2·g-1·h-1; at ambient temperatures between 14.5 and 2.0° C AMR=3.228-0.140T
a.Abbreviations AMR
active metabolic rate
- bm
body mass
- BMR
basal metabolic rate
-
h
heat transfer coefficient
- NA
noradrenaline
- NST
non-shivering thermogenesis
- NSTmax
maximum rate of NA-induced non-shivering thermogenesis
- RMR
resting metabolic rate
- RQ
respiratory quotient
- STPD
standard temperature and pressure (25°C, 1 ATM)
-
T
a
ambient temperature
-
T
b
body temperature 相似文献
8.
Daniel T. Clemens Martin E. Feder 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1992,162(7):646-650
Summary Rates of O2 uptake across isolated perfused skin of bullfrogs (Rana catesbeiana) were measured in relation to blood flow at three levels of ambient O2 tension: normoxia (O2 tension=152 torr), hypoxia (12% O2, 87 torr) and hyperoxia (42% O2, 306 torr). At bulk perfusion rates ranging from 3.4 to 10.1 l·cm-2·min-1, O2 uptake was positively correlated with hemoglobin delivery rate in both normoxia and hyperoxia, but was independent of delivery rate in hypoxia. Mean O2 uptake in normoxia was 3.8 nmol O2·cm-2·min-1 at a delivery rate of 9.8 nmol·cm-2·min-1 and 6.5 nmol O2·cm-2·min-1 at a delivery rate of 28.3 nmol·cm-2·min-1. At any given bulk perfusion rate, oxygen uptake averaged about 49% lower in hypoxia than in normoxia, decreasing in proportion to the reduction of O2 tension difference between medium and blood. In hyperoxia, O2 uptake did not increase proportionally with the difference in O2 tension between blood and medium, averaging only 50% higher at a 2.4-fold greater O2 tension difference. Cutaneous diffusing capacity for O2 averaged 0.041 nmol O2·cm-2·torr-1·min-1 during the first hour of perfusion in normoxia, and was not affected by reduction of ambient O2 tension. The results indicate that cutaneous O2 uptake in hypoxia is highly diffusion limited, and consequently, increases in cutaneous perfusion can not effectively compensate for reduction of ambient O2 tension. In hyperoxia, O2 uptake may be substantially perfusion limited because of reduced blood O2 capacitance at high O2 saturations.Abbreviations
O2 capacitance
-
C
Hb
hemoglobin concentration
- D
diffusing capacity
- PO2
medium-blood PO2 difference
- Hb
flow, hemoglobin delivery rate
- Hepes
N-[2-Hydroxyethyl]piperacine-N-[2 ethanesulfonic acid]
-
L
diff
extent of diffusion limitation
-
MO2
oxygen uptake rate
-
PO2
oxygen tension
-
S
O2 saturation 相似文献
9.
Kjell Johansen Gunnar Lykkeboe Sonja Kornerup G. M. O. Maloiy 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1980,136(1):71-76
Summary Respiratory gas exchange and blood respiratory properties have been studied in the East-African tree frogChiromantis petersi. This frog is unusually xerophilous, occupies dry habitats and prefers body temperatures near 40°C and direct solar exposure. Total O2 uptake was low at 81 l O2·g–1·h–1±19.0 (SD) at 25°C increasing to 253.5 l O2·g–1·h–1±94.8 (SD) at 40°C giving aQ
10 value of 2.1. Skin O2 uptake at 25°C was 38.5% of total. The gas exchange ratio was 0.71 for whole body gas exchange, 0.61 for the lungs and 1.02 for the skin at 25°C.Blood O2 affinity was low with aP
50 of 47.5 mmHg at 25°C and pH 7.65. Then
H-value at 25°C increased from 2.7 aroundP
50 to 5.0 at O2 saturations exceeding 70–80%. Surprisingly, blood O2 affinity was nearly insensitive to temperature expressed by a H value of ±1.0 kcal·mole between 25 and 40°C.The adaptive significance of the low O2 affinity, the increase ofn
H with O2 saturation and the temperature insensitive O2-Hb binding is discussed in relation to the high and fluctuating body temperatures ofChiromantis. 相似文献
10.
Vast areas of southern Chile are now covered by second-growth forests because of fire and logging. To study successional patterns after moderate-intensity, anthropogenic fire disturbance, we assessed differences in soil properties and N fluxes across a chronosequence of seven successional stands (2–130 years old). We examined current predictions of successional theory concerning changes in the N cycle in forest ecosystems. Seasonal fluctuations of net N mineralization (Nmin) in surface soil and N availability (Na; Na=NH
4
+
–N+NO
3
–
–N) in upper and deep soil horizons were positively correlated with monthly precipitation. In accordance with theoretical predictions, stand age was positively, but weakly related to both Na (r
2=0.282, P<0.001) and total N (Ntot; r
2=0.192, P<0.01), and negatively related to soil C/N ratios (r
2=0.187, P<0.01) in surface soils. A weak linear increase in soil Nmin (upper plus deep soil horizons) was found across the chronosequence (r
2=0.124, P<0.022). Nmin occurred at modest rates in early successional stands, suggesting that soil disturbance did not impair microbial processes. The relationship between N fixation (Nfix) in the litter layer and stand age best fitted a quadratic model (r
2=0.228, P<0.01). In contrast to documented successional trends for most temperate, tropical and Mediterranean forests, non-symbiotic Nfix in the litter layer is a steady N input to unpolluted southern temperate forests during mid and late succession, which may compensate for hydrological losses of organic N from old-growth ecosystems. 相似文献
11.
K?re B. Hagen Jostein Hallen Karin Harms-Ringdahl 《European journal of applied physiology and occupational physiology》1993,67(4):291-297
To establish safe levels for physical strain in occupational repetitive lifting, it is of interest to know the specific maximal working capacity. Power output, O2 consumption, heart rate and ventilation were measured in ten experienced forestry workers during maximal squat and stoop repetitive lifting. The two modes of repetitive lifting were also compared with maximal treadmill running. In addition, electromyogram (EMG) activity in four muscles was recorded and perceived central, local low-back and thigh exertion were assessed during the lifting modes. No significant difference was found in power output between the two lifting techniques. Despite this the mean O2 consumption was significantly greater during maximal squat lifting [38.7 (SD 5.8) ml·kg–1-·min–1] than maximal stoop lifting [32.9 (SD 5.7) ml·kg–1·min–1] (P<0.001). No significant correlation was found between O2 consumption (in millilitres per kilogram per minute) during maximal treadmill running and maximal stoop lifting, while O2 consumption during maximal squat lifting correlated highly with that of maximal treadmill running (r=0.928, P<0.001) and maximal stoop lifting (r=0.808, P<0.01). While maximal heart rates were significantly different among the three types of exercise, no such differences were found in the central rated perceived exertions. Perceived low-back exertion was rated significantly lower during squat lifting than during stoop lifting. The EMG recordings showed a higher activity for the vastus lateralis muscle and lower activity for the biceps femoris muscle during squat lifting than during stoop lifting. Related to the maximal voluntary contraction, the erector spinae muscle showed the highest activity irrespective of lifting technique. 相似文献
12.
Estelle V. Lambert David P. Speechly Steven C. Dennis Timothy D. Noakes 《European journal of applied physiology and occupational physiology》1994,69(4):287-293
These studies investigated the effects of 2 weeks of either a high-fat (HIGH-FAT: 70% fat, 7% CHO) or a high-carbohydrate (HIGH-CHO: 74% CHO, 12% fat) diet on exercise performance in trained cyclists (n = 5) during consecutive periods of cycle exercise including a Wingate test of muscle power, cycle exercise to exhaustion at 85% of peak power output [90% maximal oxygen uptake (
O2max), high-intensity exercise (HIE)] and 50% of peak power output [60%
O2max, moderate intensity exercise (MIE)]. Exercise time to exhaustion during HIE was not significantly different between trials: nor were the rates of muscle glycogen utilization during HIE different between trials, although starting muscle glycogen content was lower [68.1 (SEM 3.9) vs 120.6 (SEM 3.8) mmol · kg –1 wet mass, P < 0.01] after the HIGH-FAT diet. Despite a lower muscle glycogen content at the onset of MIE [32 (SEM 7) vs 73 (SEM 6) mmol · kg –1 wet mass, HIGH-FAT vs HIGH-CHO, P < 0.01], exercise time to exhaustion during subsequent MIE was significantly longer after the HIGH-FAT diet [79.7 (SEM 7.6) vs 42.5 (SEM 6.8) min, HIGH-FAT vs HIGH-CHO, P<0.01]. Enhanced endurance during MIE after the HIGH-FAT diet was associated with a lower respiratory exchange ratio [0.87 (SEM 0.03) vs 0.92 (SEM 0.02), P<0.05], and a decreased rate of carbohydrate oxidation [1.41 (SEM 0.70) vs 2.23 (SEM 0.40) g CHO · min–1, P<0.05]. These results would suggest that 2 weeks of adaptation to a high-fat diet would result in an enhanced resistance to fatigue and a significant sparing of endogenous carbohydrate during low to moderate intensity exercise in a relatively glycogen-depleted state and unimpaired performance during high intensity exercise. 相似文献
13.
V. Bunc J. Heller 《European journal of applied physiology and occupational physiology》1994,68(1):25-29
The aim of this study was to assess the effects of increasing specific (paddling erogmeter) and non-specific (cycle ergometer) exercise on parameters relating to the ventilatory threshold (Thvent) and work efficiency in 11 young female flat-water kayakists. When these trained subjects were tested using non-specific workloads, their oxygen uptake (VO2) values at Thvent, as a percentage ofVO2max (%VO2max), were close to those of untrained subjects [74.2 (5.6) %VO2max, mean (SD)]. However, when we tested the same subjects using specific exercise, we recorded values typical of highly trained athletes [84.8 (4.7) %VO2max). For the non-specific exercise on the cycle erogmeter, we recorded work efficiency values close to those of untrained subjects [22.3 (2.5) %]; however, for the specific exercise on the paddling ergometer, we recorded much lower values [13.4 (3.0) %] both at the level of Thvent. The work efficiency at two warm-up submaximal exercise loads on the paddling ergometer was non-significantly lower than values at Thvent [12.3 (2.8) % and 12.9 (2.9) % respectively]. Significant correlations were found between maximal-performanceVO2 (ml · kg–1 · min–1) and performance at Thvent during paddling and race performance (0.623, 0.630 and 0.648 respectively, allP<0.05). Because the results of both specific and non-specific submaximal exercise tests are different, we suggest caution in the interpretation of physiological variables that may be sensitive to training status. The evaluation of Thvent and work efficiency as supplementary parameters during laboratory studies enables the determination of the effectiveness of the training process and the specific adaptation of the subjects. 相似文献
14.
R. Turcotte L. Kiteala J. E. Marcotte H. Perrault 《European journal of applied physiology and occupational physiology》1997,75(5):425-430
The purpose of this investigation was to examine if exercise-induced arterial oxyhemoglobin desaturation selectively observed
in highly trained endurance athletes could be related to differences in the pulmonary diffusing capacity (D
L) measured during exercise. The D
L of 24 male endurance athletes was measured using a 3-s breath-hold carbon monoxide procedure (to give D
LCO) at rest as well as during cycling at 60% and 90% of these previously determined O2max. Oxyhemoglobin saturation (S
aO2%) was monitored throughout both exercise protocols using an Ohmeda Biox II oximeter. Exercise-induced oxyhemoglobin desaturation
(DS) (S
aO2% < 91% at O2max) was observed in 13 subjects [88.2 (0.6)%] but not in the other 11 nondesaturation subjects [NDS: 92.9 (0.4)%] (P ≤ 0.05), although O2max was not significantly different between the groups [DS: 4.34 (0.65) l / min vs NDS: 4.1 (0.49) l / min]. At rest, no differences
in either D
LCO [m1 CO · mmHg−1 · min−1: 41.7 (1.7) (DS) vs 41.1 (1.8) (NDS)], D
LCO /
A
[8.2 (0.4) (DS) vs 7.3 (0.9) (NDS)], MVV [l / min: 196.0 (10.4) (DS) vs 182.0 (9.9) (NDS)] or FEV1/FVC [86.3 (2.2) (DS) vs 82.9 (4.7) (NDS)] were found between groups (P ≥ 0.05). However,
E /O2 at O2max was lower in the DS group [33.0 (1.1)] compared to the NDS group [36.8 (1.5)] (P ≤ 0.05). Exercise D
LCO (m1 CO · mmHg−1 · min−1 ) was not different between groups at either 60% O2max [DS: 55.1 (1.4) vs NDS: 57.2 (2.1)] or at 90% O2max [DS: 61.0 (1.8) vs NDS: 61.4 (2.9)]. A significant relationship (r = 0.698) was calculated to occur between S
aO2% and
E /O2 during maximal exercise. The present findings indicate that the exercise-induced oxyhemoglobin desaturation seen during submaximal
and near-maximal exercise is not related to differences in D
L, although during maximal exercise S
aO2 may be limited by a relatively lower exercise ventilation.
Accepted: 25 September 1996 相似文献
15.
Oxygen consumption and flight muscle activity during heating in workers and drones of Apis mellifera
Franz Goller Harald E. Esch 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1991,161(1):61-67
Summary Instantaneous oxygen consumption, muscle potential frequency, thoracic and ambient temperature were simultaneously measured during heating in individual workers and drones of honey bees. Relationships between these parameters and effects of thoracic temperature on power input and temperature elevation were studied. Oxygen consumption increased above basal levels only when flight muscles became active. Increasing muscle potential frequencies correlated with elevated oxygen consumption and raised thoracic temperature. The difference between thoracic and ambient temperature and oxygen consumption were linearly related. Oxygen consumption per muscle potential (l O2 · g
–1
thorax
· MP–1) was two-fold higher in drones than in workers. However, oxygen consumption for heating the thorax (l O2 · g
–1
thorax
· (Tth-Ta) · °C–1) was nearly the same in workers and drones. Thoracic temperature affected the amount of oxygen consumed per muscle potential (R10=1.5). Achieved temperature elevation per 100 MP was more temperature sensitive in drones (R10=6–10) than in workers (R10=3.6). Q10 values for oxygen consumption were 3 in workers and 4.5–6 in drones. Muscle potential frequency decreased with a Q10=1.8 in workers and 2.7 in drones. Heating behaviour of workers and drones was different. Drones generated heat less continuously than workers, and showed greater interindividual variability in predilection to heat. However, the maximal difference between ambient and thoracic temperature observed was 22 °C in drones and 14 °C in workers, indicating greater potential for drones.Abbreviations
DL
dorsal-longitudinal muscle
-
DV
dorsoventral muscle
-
MP
muscle potential
-
T
a
ambient temperature
-
T
th
thoracic temperature 相似文献
16.
17.
C. Carey O. Dunin-Borkowski F. Leon-Velarde D. Espinoza C. Monge 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1994,163(8):649-656
Oxygen consumption, air cell gases, hematology, blood gases and pH of Puna teal (Anas versicolor puna) embryos were measured at the altitude at which the eggs were laid (4150 m) in the Peruvian Andes. In contrast to the metabolic depression described by other studies on avian embryos incubated above 3700 m, O2 consumption of Puna teal embryos was higher than even that of some lowland avian embryos at equivalent body masses. Air cell O2 tensions dropped from about 80 toor in eggs with small embryos to about 45 toor in eggs containing a 14-g embryo; simultaneously air cell CO2 tension rose from virtually negligible amounts to around 26 torr. Arterial and venous O2 tensions (32–38 and 10–12 toor, respectively, in 12- to 14-g embryos) were lower than described previously in similarly-sized lowland wild avian embryos or chicken embryos incubated in shells with restricted gas exchange. The difference between air cell and arterial O2 tensions dropped significantly during incubation to a minimum of 11 torr, the lowest value recorded in any avian egg. Blood pH (mean 7.49) did not vary significantly during incubation. Hemoglobin concentration and hematocrits rose steadily throughout incubation to 11.5 g · 100 ml-1 and 39.9%, respectively, in 14-g embryos.Abbreviations PO2
partial pressure gradient of O2
- BM
body mass
-
D
diffusion coefficient
-
G
gas conductance (cm3·s-1·torr-1)
-
conductance to water vapor
- IP
internal pipping of embryos
-
P
ACO2
partial pressure of carbon dioxide in air cell
-
P
AO2
partial pressure of oxygen in air cell
-
P
aCO2
partial pressure of carbon dioxide in arterial blood
-
P
aCO2
partial pressure of oxygen in arteries
-
P
H
barometric pressure (torr)
-
PCO2
partial pressure of carbon dioxide
-
P
IO2
partial pressure in ambiant air
-
PO2
partial pressure of oxygen
-
P
VCO2
venous carbon dioxide partial pressure
-
P
VO2
mixed venous oxygen partial pressure
- SE
standard error
-
VO
2
oxygen consumption 相似文献
18.
To clarify the potential use of hydrophobicity-related traits of aerial conidia in formulation design of fungal biocontrol
agents, hydrophobicity rates (H
r) and surface areas (S
a) of aerial conidia were assessed with 48 strains of Beauveria bassiana,
Isaria fumosorosea and Metarhizium spp. Inter- or intra-specific variation was large in H
r (59.7–92.2%) and S
a (7.9–25.3 μm2 conidium−1) measurements, which were significantly correlated (r
2 = 0.55). Six isolates of the three fungi with distinguished H
r and S
a were further studied. Conidial wall proteins of these isolates were sequentially extracted with sodium dodecyl sulfate (SDS),
formic acid (FA) and trifluoroacetic acid (TFA). Their H
r values were significantly correlated to the contents (P
c) of TFA-soluble, but FA-insoluble, proteins (2.7–44.8 μg per 107 conidia; r
2 = 0.79) and reduced drastically by the FA/TFA treatments, which eliminated the hydrophobin-based rodlet layers of conidial
surfaces. However, the SDS treatments had no effect on either H
r or rodlet layers. The dispersancy of a tested emulsifier to oil formulations of the six isolates in water was adversely correlated
to their H
r (r
2 = 0.94). The results indicate that both P
c and S
a are inherent hydrophobicity-related traits and can be utilized to select fungal biocontrol candidates for improved formulation
and application. 相似文献
19.
Jo Smith Lars Mc Naughton 《European journal of applied physiology and occupational physiology》1993,67(5):420-425
This experiment investigated the effects of intensity of exercise on excess postexercise oxygen consumption (EPOC) in eight trained men and eight women. Three exercise intensities were employed 40%, 50%, and 70% of the predetermined maximal oxygen consumption (VO2max). All ventilation measured was undertaken with a standard, calibrated, open circuit spirometry system. No differences in the 40%, 50% and 70% VO2max trials were observed among resting levels of oxygen consumption (V02) for either the men or the women. The men had significantly higher resting VO2 values being 0.31 (SEM 0.01) 1·min–1 than did the women, 0.26 (SEM 0.01) 1·min–1 (P < 0.05). The results indicated that there were highly significant EPOC for both the men and the women during the 3-h postexercise period when compared with resting levels and that these were dependent upon the exercise intensity employed. The duration of EPOC differed between the men and the women but increased with exercise intensity: for the men 40% – 31.2 min; 50% – 42.1 min; and 70% – 47.6 min and for the women, 40% – 26.9 min; 50% – 35.6 min; and 70% – 39.1 min. The highest EPOC, in terms of both time and energy utilised was at 70% VO2max. The regression equation for the men, where y=O2 in litres, and x=exercise intensity as a percentage of maximum was y=0.380x + 1.9 (r
2=0.968) and for the women is y=0.374x–0.857 (r
2=0.825). These findings would indicate that the men and the women had to exercise at the same percentage of their VO2max to achieve the maximal benefits in terms of energy expenditure and hence body mass loss. However, it was shown that a significant EPOC can be achieved at moderate to low exercise intensities but without the same body mass loss and energy expenditure. 相似文献
20.
S. F. Perry 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1990,159(6):761-769
Summary The respiratory surface area (SAR) per kilogram body mass (MB), the harmonic mean thickness of the air-blood barrier (htR) in the gas exchange tissue, and the anatomical diffusion factor (ADF=SAR/htR per MB) were calculated for four juvenile Nile crocodiles. The ADF of three small specimens (mean MB=3.59 kg) was 625 cm2·m–1·kg–1. The values varied considerably among individuals and were similar to that of a 5.68-kg specimen (593 cm2·m–1·kg–1). Only 9% of the ADF is located in the anterior third of the lung, which because of its conical shape makes up only 14 percent of the total lung volume. Particularly in the middle third of the lung, the proximal region near the intrapulmonary bronchus displays a greater ratio of respiratory/non-respiratory surface areas than do more distally located sampling sites. The htR is also significantly smaller proximally than distally. The cumulative ADF per unit MB is greater than that previously reported for this species on the basis of overall estimates of SAR and htR, but is still less than that of lizards and testudinids. The disposition of ADF between distal air storage region and the intrapulmonary bronchus is consistent with a bidirectional cross-current gas exchange model.Abbreviations
ADF
anatomical diffusion factor
- %AR
percent of SA included in the effective respiratory zone
-
M
B
body mass
-
NVP
non-ventilatory period
- %P
percent of total lung volume containing parenchyma
-
S
A
total surface area of intrapulmonary septa
-
S
ANR
that portion ofS
A
lying out the effective respiratory zone
-
S
V
surface-to-volume ratio in the parenchyma
- htR
harmonic mean thickness of the air-blood tissue barrier within the respiratory zone
-
V
P
parenchymal volume
-
VP
ventilatory period 相似文献