用最优化技术寻索同位素稀释质谱法的稀释条件

文章考虑了被测元素有任意个同位素质谱峰,及同位素丰度比测定数据具有不等精度的情况,利用最优化方法来确定同位素稀释质谱法的最优稀释条件,并且编制了计算程序,该程序具有四项主要功能。利用编制的计算程序进行了实例计算,得到满意的结果。     

Effect of dexamethasone on endothelial nitric oxide synthase in experimental congenital diaphragmatic hernia

AIMS: To study the effect of prenatal glucocorticoid treatment on endothelial nitric oxide synthase (eNOS) expression in rats with congenital diaphragmatic hernia (CDH). METHODS: CDH was induced in fetal rats by the maternal administration of nitrofen on day 9.5 of gestation. Dexamethasone was administered on days 18.5 and 19.5 before delivery of the fetuses on days 20.5 and 21.5. Pulmonary eNOS protein expression was studied by western immunoblotting and immunohistochemistry. RESULTS: On day 20.5, eNOS expression was significantly reduced in CDH pups compared with normal control rats. Dexamethasone treated CDH pups had eNOS concentrations equivalent to those of normal animals. By day 21.5, however, there was no detectable difference in eNOS expression between the experimental groups. CONCLUSIONS: eNOS is deficient in near term (day 20.5) CDH rats. Dexamethasone restores eNOS expression in these animals to that seen in normal rat lungs. At term, the precise role of eNOS in the pathophysiology of CDH remains uncertain.     

Antithrombotic therapy prescribed for patients with non-rheumatic atrial fibrillation

Patients with non-rheumatic atrial fibrillation have a fivefold increased risk of stroke. Warfarin reduces this risk by approximately two thirds, but evidence for benefit from aspirin is less compelling. We assessed whether our current practice reflects the message of the trials. In a retrospective case record study we reviewed notes of 131 patients with atrial fibrillation (AF), mean age 79 (range 53-95) years, admitted to a medical unit (72) or geriatric assessment unit (59). Thirty-two patients had paroxysmal AF. Of 115 patients with nonrheumatic AF, 36 (31%) had one or more recorded contraindication to anti-coagulation. Although 79 patients (69%) had no recorded contraindication to warfarin, only 2 took warfarin and 15 aspirin prior to admission. Ten patients commenced warfarin and 8 aspirin before discharge. Thirty-nine patients (53%) without contraindication, were discharged without antithrombotic therapy. Despite evidence to support anticoagulating patients with non-rheumatic AF, this rarely occurs.     

Increased oxygen radical and high-dietary-carbohydrate pancreatic damage

These data suggest that an improved understanding of the relationship between high dietary carbohydrate and the rate of lipid peroxidation may give some insight into possible treatment modalities for pancreatic damages and may shed light on molecular mechanisms underlying certain pathological processes. High dietary carbohydrate lesions are age related and induced alterations on ceruloplasmin, phospholipids, total proteins, copper and zinc serum levels. Significantly increased serum and pancreatic amylase, and lipoperoxide determinations were observed in 20 month old rats. Cu-Zn superoxide dismutase was decreased in these animals. Daily injection of Cu-Zn superoxide dismutase conjugated with polyethylene glycol (SOD-PEG) prevented the serum and pancreatic changes, indicating that superoxide radical is an important intermediate to high dietary carbohydrate lesion.     

Comparative nutritive value of winged bean (Psophocarpus tetragonolobus (L) DC) and other legumes grown in Tanzania

BACKGROUND: In order to assess the efficiency of flow-controlled shunts in reducing shunt failure in the treatment of adult hydrocephalus (with a special focus on overdrainage complications), a series of 289 patients was analyzed through a retrospective and comparative study performed in three neurosurgical departments. METHODS: A group of 142 adult patients suffering from hydrocephalus were operated on using a conventional differential pressure (DP) shunt and compared with a group of 147 adult patients operated on using flow-controlled (FC) system (Orbis-Sigma, Cordis). Only the first complication, which required a surgical revision within the first 2 years after shunt implantation, was taken into account for each patient and analyzed using life-table methods. RESULTS: The actuarial risk of shunt infection in the two groups is respectively 8.3% and 10.9% at 1 year (nonsignificant difference). The actuarial risk of mechanical complications at 1 year is 38% for the DP patients and 10% for the FC patients (p = 0.0001); this difference is largely due to a decrease of complications related to overdrainage phenomenon (14/142 subdural collections were observed in the DP group versus 1/147 in the FC group) (p = 0.0001). CONCLUSION: The conclusion of this cooperative and retrospective study is that the use of a flow-controlled system decreases the risk of mechanical complications related to the hydrodynamic properties of the shunts used in the treatment of adult hydrocephalus, especially those related to overdrainage.     

水力控制棒驱动系统的步进过程基本理论模型

从理论角度深入阐述，解释水力控制棒驱动系统这一新技术的工作机理，为进一步的分析，研究工作及推广应用该系统建立理论基础。文章介绍了水力控制棒驱动系统的工作原理，在合理简化，假设的基础上建立了水力控制棒驱动系统步进过程的理论模型，并给出了其相应的数学描述，针对几种实际工况进行了计算，并与实验结果进行比较，结果表明，理论计算结果与实验结果相吻合，验证了该模型的合理性和可行性。     

烧结矿中MgO配加方式的改进试验

对济钢烧结矿 Mg O的几种不同带入方式进行了工业试验和生产实践。指出在济钢目前生产条件下 ,在烧结生产中配加高 Mg O铁精粉和高 Mg O熔剂 ,是确保铁前系统稳定、优化高效的有效途径     

Clinical trials in the elderly. Should we do more?

In this study, SPF rat models were used. The purpose of the study was to observe the impairment of gut barrier function subsequent to long-term TPN, and evaluate the effect of TPN enriched by alanyl-glutamine (Ala-Gln) on the gut. After 7 day standard TPN, there was a significant decrease of CD3+, CD4+, CD8+ and IgA-containing plasma cells in lamina propria. The percentage of intestinal bacteria coated by S-IgA declined, and bacterial adherence to intestinal epithelial cells increased with an increased incidence of bacterial translocation to mesenteric lymph nodes. All these adverse effects could be attenuated by addition of Ala-Gln to TPN solutions or oral glutamine (Gln) or Ala-Gln administration. The results of the study suggested that long-term standard TPN impaired the immune gut barrier function and therefor facilitated enterogenic infection, and addition of Gln or Ala-Gln significantly benifited gut barrier protection and infection prevention, which might be important to clinical practice.