Renal responses of Australian lungfish to vasotocin, angiotensin II, and NaCl infusion

The Australian lungfish (Neoceratodus forsteri) responds to intravenous injections of 0.63 ng/kg or more of arginine vasotocin with increased dorsal aortic blood pressure, inulin clearance, urine flow, and tubular rejection of Na+. Single injections of 1 ng/kg or more of angiotensin II or norepinephrine also increase dorsal aortic pressure but do not cause consistent diuresis and natriuresis, Continuous infusions of angiotensin II or repeated injections of norepinephrine produce sustained hypertension and more modest diuresis and natriuresis than are seen after injections of arginine vasotocin that cause less hypertension. Infusions of isosmolar or hyposmolar NaCl solutions increase blood pressure, inulin clearance, urine flow, and tubular Na+ rejection in a manner resembling the response to argininge vasotocoin injections. These data are consistent with the hypothesis that arginine vasotocin is released in response to volume expansion in lungfishes and that it may act on the kidney as a diuretic and natriuretic hormone. They do not rule out a more direct action of expansion on renal functions.     

电厂蒸汽回路系统中腐蚀损伤的决定论预测

局部腐蚀,包括点腐蚀、应力腐蚀开裂和腐蚀疲劳是导致电厂发电装置损伤的重要原因,它们诱发50%以上的意外停机事故。迄今,腐蚀破坏的预测一直沿用经验和统计的方法,但是,由于已证实该方法的适用性和其结果的准确性欠佳,故不宜作为例行检修规程的基础。本文提出了预测局部腐蚀损伤的决定论方法,并使用这个方法说明点腐蚀如何引发低压蒸汽轮机涡轮盘Wilson线下游部位的应力腐蚀开裂(SCC),我们的计算表明SCC的萌发与扩展对蒸汽小氧含量、冷凝液膜的环境和涡轮盘所承受的应力这三个因素敏感。     

STUDY OF K_(2)O·6TiO_(2) WHISKER REINFORCED AI COMPOSITES FOR THEIR MECHANICAL PROPERTIES AND INTERFACIAL STRUCTURES

A newly developed whisker K_2O 6TiO_2 reinforeed 6061Al composite was prepared bysqueeze casting process.The flexural strength of the composite is 518MPa,and deereasesto 490MPa after T6 treatment.The hardness of the composite also shows the similarchange while T6 treating.The results of HRTEMobservation may explaine this property.change.It was considered that there is a continuous TiO layer at the whisker-matrix inter-face,which is easily to react with the segregated Mg and to form MgTi_2O_4,MgAl_2O_4.Thethickening of TiO layer after T6 treatment is the main reason resulting is strength degra-dation of composite.     

Experimental and numerical study of transient laminar counterflow diffusion flames

In the present article, we analyze the nonsteady behavior of counterflow diffusion flames subjected to a time-dependent injection velocity in the case of hydrogen—air flames. The numerical study, using a finite-difference implicit linear multistep method and employing complex kinetics, is done for sinusoidal injection velocity variations, for moderate values and also for values near the extinction limit. The frequency response is obtained in these different cases. The experimental setup comprises two axisymmetric nozzles. In order to change the inlet velocities periodically, we use a vibrating mechanism in each burner. The amplitude and the frequency of injection velocities of the opposed nozzles are synchronously modified. The OH radical emission intensity is used to measure the flame response to velocity fluctuations. The experimental results are compared to numerical calculations. Good agreement is obtained in this comparison.Laboratoire EM2C, CNRS, Ecole Centrale Paris, 92295 Chatenay-Malabry cedex, France. Published in Fizika Goreniya i Vzryva, Vol. 29, No. 3, pp. 61–66, May–June, 1993.     

Cholera in Portugal, 1974.I. Modes of transmission

In April-November 1974, Portugal had a cholera epidemic caused by Vibrio cholerae El Tor Inaba with 2467 bacteriologically confirmed hospitalized cases and 48 deaths. Most of the country was affected, with 17 of the 18 districts reporting cases. V. cholerae was isolated from 42 per cent of shellfish tested during the epidemic, and an epidemiologic study found that a history of consumption of raw or poorly cooked cockles was significantly more common among cholera patients than among paired controls. Water from a spring and a brand of commercially bottled water were also found to be vehicles of transmission of cholera. Although night soil was sometimes used on gardens, consumption of raw fruits and vegetables was not associated with illness.     

The Canter Background Interference Procedure (BIP): effects of demographic variables on diagnosis

This paper reports a positive association between demographic variables and Canter BIP diagnostic classification. Ss are 209 middle-aged men and include psychiatric and medical patients and non-patients. To evaluate the joint effects of the demographic variables, a discriminate analysis was performed on the total sample. Race and educational level alone predicted BIP diagnosis in 67% of the cases. While none of the demographic variables was related significantly to BIP diagnosis when a discriminate analysis was performed on whites alone, age and educational level were related significantly to BIP diagnosis when a discriminate analysis was performed on blacks alone.     

The application of radionuclide infarct scintigraphy to diagnose perioperative myocardial infarction following revascularization

To evaluate the application of radionuclide infarct scintigraphy to diagnose myocardial infarction after revascularization, we obtained postoperative technetium 99m pyrophosphate myocardial scintigrams, serial electrocardiograms and CPK-MB isoenzymes in ten control and 51 revascularized patients. All control patients had negative electrocardiograms and scintigrams, but eight had positive isoenzymes. Eight revascularized patients had positive electrocardiograms, images and enzymes and two had positive scintigrams and enzymes with negative electrocardiograms. Thirty-four patients with negative electorcardiograms and scintigrams had positive isoenzymes; in only seven patients were all tests negative. Our data suggest radionuclide infarct scintigraphy is a useful adjunct to the electrocardiogram in diagnosing perioperative infarction. The frequent presence of CPK-MB in postoperative patients without other evidence of infarction suggests that further studies are required to identify all factors responsible for its release.