水平管中气固两相流的混沌特征分析

对水平管密相气力输送系统的混沌动力学行为进行了分析，对煤粉浓度信号时间序列的最大Lyapunov指数和关联维数进行了计算。结果表明，系统的最大Lyapunov指数均大于零，这充分说明煤粉在水平管中的密相气力输送存在混沌特征。从密相移动床流区到沉积层流区，混沌吸引子由大变小，关联维数从1．5359减小到1．0764。说明从密相移动床流区到沉积层流区，流体系统运动的混沌程度逐渐减弱。     

Maximal and submaximal oxygen uptake during running: how should body mass be accounted for?

Oxygen uptake during running, i.e., the running economy, is an important factor in determining running performance in endurance events. The relation to performance is particularly strong when the aerobic running capacity is calculated, i.e., when running economy is related to the maximal oxygen uptake. There is considerable interindividual variation in running economy, and the reason for this is only partly understood. To some extent, this may be due to the way in which the oxygen uptake during running is usually expressed. This may expecially be true when subjects with different or changing body masses are compared. Several lines of evidence, including earlier animal studies as well as more recent human studies, favor the expression of submaximal and maximal oxygen uptake during running in terms of ml · kg^−0.75· min⁻¹ rather than as ml · kg⁻¹· min^−1.     

海拔3417m世居及移居者无氧代谢阈与左心功能关系的探讨

在海拔３４１７ｍ对１８名健康世居藏族和１６名移居汉族用Ｊｅａｇｅｒ气体代谢自动分析系统和心阴抗图测定了无氧阈和最大摄氧量时的ＳＶ、ＣＯ、ＰＥＰ／ＬＶＥＴ和ＳａＯ２。结果显示：在海拔３４１７ｍ测得ＡＴ值明显低于海平面；世居藏族ＡＴ出现较晚，并且ＡＴ时的功率、ＶＯ２、ＭＶ、ＨＲ、ＣＯ、ＳＶ均高于移居汉族，而ＰＥＴ／ＬＶＥＴ比值小于移居组；两组的ＳＶ峰值出现时间不同，蕊居组在ＡＴ或ＡＴ以后出现的占７２％     

Continuous recording of urethral activity in healthy female volunteers

The pressure variations at the maximal urethral closure pressure (MUCP) were continuously recorded in healthy female volunteers by means of a two-point microtip transducer catheter for one hour. Before the investigation a normal voiding was assured objectively and bladder instability was excluded. All women showed pressure variations both at the MUCP and more distally. The pressure variations, from 3 to 66 cm H₂O, showed rhythmicity and three frequency ranges could be identified. Slow pressure waves with a frequency of one in eight to 19 minutes were observed. Relatively fast-pressure waves were observed (one every one to four minutes) and relatively fast-frequency pressure waves were observed (rate: one to eight per minute). The pressure variations of the urethra seem to be an aspect of normal urethral physiology possibly contributing to continence and urinary tract infection prevention.     

Physiological Effects of Mental Stress and Orthostasis in Young Insulin-Dependent Diabetic Patients

ABSTRACT. The effects of procedures which stimulate sympathetic activity, viz. mental stress induced by a colour-word conflict test (CWT) for 20 min, and orthostasis (ORT) for 8 min were studied in 8 young (16-20 yr) insulin-dependent diabetes mellitus (IDDM) patients and 9 age and sex-matched healthy controls. The IDDM patients showed no signs of neuropathy or retinopathy and their mean HbA_1c value was 8.4 ±0.6% (normal value < 5.0 %). Blood pressure and heart rate increased significantly during CWT and ORT in both groups. The changes in systolic blood pressure and heart rate were comparable in both groups during CWT; the IDDM group showed a higher ( p < 0.05) heart rate after 8 min of orthostasis, however. CWT and ORT elicited equivalent increases in noradrenaline in venous plasma in both groups ( p < 0.05), but the IDDM patients had 50% lower values ( p < 0.01) at rest, during CWT and at rest after CWT than controls. CWT and ORT evoked equivalent plasma adrenaline increases in both groups. The lipolysis marker, plasma glycerol, was about 40 % lower ( p < 0.05) in the IDDM group before and after CWT. Yet, mental stress evoked equivalent increases in glycerol levels ( p < 0.01) in both groups. These findings indicate that sympathetic activity in the young diabetic patients without signs of neuropathy may be blunted.     

One month maximal electrostimulation for genuine stress incontinence in women

While awaiting surgery for genuine urinary stress incontinence, 51 women with were treated at home for 1 month with vaginal maximal electrostimulation. They were evaluated subjectively, urodynamically, and with two different pad tests. Six patients (12%) were cured and 17 (33%) were much improved, subjectively and objectively. Statistically significant improvement was observed for both pad tests. Successful treatment was significantly more likely in women with milder degrees of incontinence but was unrelated to age or urethral pressure. Patient acceptance was excellent and apart from some vaginal soreness no complications were seen. Sixteen patients (31%) elected not to be operated on. These 16 patients were reevaluated after 1 year and 13 (81%) had maintained their improvement. Three had disimproved but were still better than before treatment; 2 again refused surgery and 1 opted for surgery. Therefore, 15 of 51 (29%) operations were saved after 1 year. This conservative treatment for stress incontinence is safe, simple, inexpensive, and reasonably successful. © 1994 Wiley-Liss, Inc.     

Skeletal Muscle Adaptations to Physical Training in Type II (Non-insulin-dependent) Diabetes Mellitus

Seven middle-aged men with manifest type II diabetes mellitus underwent an endurance training programme for 10–15 weeks. The maximal aerobic capacity, as well as the endurance capacity, was improved by 10% (p<0.05). The intramuscular glycogen store increased by more than 80% (p<0.05) from 350 μmol/g dw (dry weight), and the activities of citrate synthase and 3-hydroxy-acyl-CoA dehydrogenase increased by more than 50% (p<0.05) and 30% (p<0.05). The activity of glycogen synthase was decreased by approximately 20% (p<0.05), whereas lactate dehydrogenase remained unchanged. Capillaries/fibre and fibre area increased by more than 50% (p<0.05) and 30% (p<0.05) leaving the area of supply constant. Training did not influence fasting blood lipids and glucose, glycosylated hemoglobin, oral glucose tolerance, and insulin response to an oral glucose load measured 72 hours post-exercise. It is concluded that patients with manifest type II diabetes, as normoglycaemic individuals, adapt to physical training. However, no persistent effect on glucohomeostasis and lipaemia is produced by short-term training in the diabetic patients.     

Beta-adrenergic blockade and training in healthy men—effects on central circulation

The effect of chronic β-adrenergic blockade on central circulatory adaptations to physical training was investigated. 16 healthy sedentary males (20–31 yrs) trained on cycle ergometers 40 min/day, 4 days a week for 8 weeks at a work load that during the last 5 weeks corresponded to 75% of the pretraining VO₂ max. In a single blind way, 8 subjects were during the training period treated with the β-adrenergic receptor blocker propranolol (160 mg/day), while the remaining 8 received placebo tablets. Pretraining tests were performed before the start of medication and posttraining tests were performed 6 days after the last day of training and medication. The training program resulted in a similar increase (8%) in VO₂ max in both groups (p<0.01). The resting heart rate (-4 beats/min; p<0.05) as well as the exercise heart rate at a moderate work load (120 W: -11 beats/min; p<0.01) decreased with training, and no significant difference was seen between the 2 groups. At a high work load (180 W), however, the heart rate decreased significantly more with training in the placebo group as compared with the β-blockade group (-19 vs.-7 beats/min; p<0.05). The oxygen pulse (VO₂/HR) increased in both groups at 120 W (+6%; p<0.01). At 180 W the oxygen pulse increased only in the placebo group (+8%; p<0.05). The estimated stroke volume at 120 and 180 W, as determined by impedance cardiography, did not change significantly with training although there was a tendency towards an increase in the placebo group only. The resting left ventricular wall thickness and diameter, as determined by echocardiography, did not change significantly with training in either group.—In conclusion, the present study indicates that a moderate degree of β-adrenergic blockade does not prevent or impair the training-induced increase in the maximal oxygen uptake. During submaximal work, however, the circulatory adaptation may be less apparent if training has been performed during partial blockade of the sympathoadrenal system.     

The prognostic value of maximal exercise testing soon after first myocardial infarction

The prognostic value of ST-segment depression during maximalexercise test performed in the third to fourth week after acutemyocardial infarction (AMI), was studied in 126 consecutivepatients with no evidence of previous myocardial infarction,unstable angina pectoris or severe heart failure. All patientson average increased their pressure-rate product by 2.6 andno complications occurred. Within the first year of follow-up,major cardiac events occurred in 9 patients (20%), and werefatal in 6 (13%), of the 46 patients who developed ST-segmentdepression during exercise. Only 3 major cardiac events (4%)occurred in the 80 patients without exercise induced ST-segmentdepression. Depression of the ST-segment on maximal exercisewas a significant predictor of subsequent cardiac events inthese survivors of first AMI.