Congenital complete tracheal rings. Report of a case

An unusual congenital tracheal anomaly is described. Complete (closed) tracheal rings, occupying the entire length of the trachea, have seldom been reported. Most affected patients succumb to respiratory infections in early infancy. Diagnosis of this anomaly is difficult during life, but radiographic and endoscopic examinations may be revealing. There is no known definitive treatment, although the airway may be managed long enough for body growth to relieve the obstruction. This rare anomaly should be considered in those cases of intermittent respiratory obstruction that are not associated with other more common causes of stridor.     

Aldosterone secretion during high sodium cerebrospinal fluid perfusion of the brain ventricles

Conscious sheep with permanent indwelling cannulae in the lateral ventricles and the cisterna magna were Na depleted and then perfused for 9 h with an artificial CSF solution. There were 3 experimental groups: Group I (n=5) received perfusion with aritifical CSF containing NA 170 MEq./1, Group II (n=7) received perfusion with artificial CSF containing Na 145 mEq./1, Group III (n=7) received no perfusion. In Group I the blood aldosterone level fell from 26.4 +/- 7.4 to 8.6 +/- 2.3 ng/100 ml by 9 h after perfusion. There was no significant change in plasma [Na] or [K], blood angiotensin II or plasma renin concentration. Blood cortisol and corticosterone levels rose. There was also a fall in post-perfusion. Group III showed no significant change in blood aldosterone concentration. Multivariate statistical analysis showed that the fall in aldosterone levels during 170 mEq./l Na perfusion could not be accounted for by changes, either alone or together, of ACTH as evidenced by alteration in blood cortisol or corticosterone, or by change of plasma [Na], [K] or renin concentrations. This data supports the hypothesis of an additional factor which may be of CNS origin being involved in the control of aldosterone secretion.     

Acute renal failure in patients with acute pancreatitis

We describe five patients with acute pancreatitis in whom acute renal failure developed in the absence of hypotension. Pancreatitis was diagnosed clinically, with mean serum and urinary amylase levels of 766 +/- 197 (SE) and 2,378 +/- 572 units/100 ml, respectively. Acute renal failure developed within 24 hours after admission in all patients. It was manifested by oliguria, elevated levels of serum creatinine (mean, 6.9 +/- 1.1 mg/100 ml) and BUN (105 +/-28 mg/100 ml); a urinary sodium level of 72.0 +/- 6.6 mEq/liter; and isosmotic urine (355 +/- 31 mOsm/liter). The mean uric acid level was 18.6 +/- 1.6 mg/100 ml. Blood pressure was recorded frequently, and the lowest mean diastolic pressure was 96 +/- 6 mm Hg. The duration of the oliguric phase of acute renal failure was 8.2 +/- 1.7 days, and all patients recovered from both the acute pancreatitis and acute renal failure. In summary, acute pancreatitis, per se, can precipitate acute renal failure. It occurs early in the course of the pancreatitis, and extreme hyperuricemia is frequent finding that does not adversely affect the recovery of renal function.     

基于视觉的复杂环境下微型飞行器自主飞控问题探讨

基于视觉的飞行控制是提高复杂环境下微型飞行器生存能力和军事应用价值的有效手段。介绍了视觉技术应用于微型飞行器姿态估计、自主导航和目标跟踪的基本方法，归纳出视觉飞控的关键技术，并探讨了一些解决方法。最后，对视觉技术的应用进行了展望。     

搅拌摩擦焊接头缺陷分析

通过对搅拌摩擦焊接焊缝中的缺陷进行分析研究,认为其缺陷主要分为外观缺陷与内部缺陷,并进一步对其缺陷位置、形态及出现原因给予了说明.     

地球、金星大气寿命的计算

假定行星大气层中气体分子的逃逸过程是准静态过程,推导出了气体分子的逃逸方程,定义了行星大气分子的逃逸率及行星大气的半寿命,给出了数学表达式.根据数学表达式,假定不同的大气温度,计算了地球和金星大气层的半寿命.结果表明,地球和金星大气层的半寿命远超过宇宙年龄(约1010y),因而是非常稳定的.本理论可应用于其他行星和月球大气层半寿命的计算.     

Antibiotic resistance patterns of metal-tolerant bacteria isolated from an estuary

Estuarine bacteria isolated on metal-containing media were also found to be antibiotic resistant; ampicillin and chloramphenicol were the antibiotics to which resistance was most common. Patterns of antibiotic resistance were found associated with a variety of taxa.