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21.
给出新型三类用理性杂交模式、根据一种修正的Hellinger-Reissner原理、建立高精度非协调轴对称实体旋转有限元时,其单元刚度矩阵的准确计算式。 相似文献
22.
成层地基固结性状中不同定义平均固结度研究分析 总被引:1,自引:0,他引:1
一维地基固结理论从传统的太沙基一维固结理论到成层地基一维固结理论中。由于实际地基大多由性质不一的成状土组成,成层地基固结度计算一直为人们所关注。固结度有按沉降(压缩量)定义的地基总平均固结度和按作用的平均有效应力(或所消散的平均孔压)定义(简称按平均孔压定义)的地基总平均固结度。但对实际工程对它们的大小比较讨论甚少,对实际的选取应用没有理论上的支持。本文从一般均质地基的固结度定义入手,在相对比较理想的土体条件假设下,系统的比较了它们的大小区别,并在单面排水条件下结论Us>Up是一定成立的,并且根据以有的半理论解编制了相应的计算程序来说明本文的正确性。 相似文献
23.
Chitra Upadhyaya Sandhya Mishra P. P. Singh Praveen Sharma 《Indian journal of clinical biochemistry : IJCB》2005,20(1):30-34
Serum antioxidant status and peroxidative stress was estimated in 30 pregnant women, their newborn infants and 25 non-pregnant
women. Serum Ascorbic acid, α-tocopherol, retinol & β-carotene levels were found to be significantly reduced and peroxidative
stress was significantly higher in mothers as compared to matched non-pregnant women. Newborn had significantly higher levels
of ascorbic acid as compared to their mother but had significantly lower levels of lipid soluble vitamins. The peroxidative
stress in newborn was found to be significantly less as compared to their mothers. A positive correlation of ascorbic acid
and α-tocopherol levels between mother and newborn reflects that their status in mother does influence the newborn status. 相似文献
24.
Gora Dadheech Sandhya Mishra Shiv Gautam Praveen Sharma 《Indian journal of clinical biochemistry : IJCB》2006,21(2):34-38
A disturbance in the antioxidant defense system including α-tocopherol, ascorbic acid and reduced glutahtione metabolism due
to free radical induced oxidative injury has been implicated in various neuro-psychiatric disorders. The roles of these antioxidants,
changes in their blood levels and correlation with oxidative stress were studied in a common psychiatric illness Schizophrenia.
Fifty-eight subjects of either sex ranging in age from 18–60 years divided into two age groups (≤40 and >40 years) diagnosed
for schizophrenia, and forty age and sex-matched normal subjects as controls were included in the study. Blood samples were
analyzed for malondialdehyde (MDA), α-tocopherol, total ascorbic acid (TAA), dehydro ascorbic acid (DHAA), reduced ascorbic
acid (RAA), leucocyte ascorbic acid (LAA) and reduced glutathione (GSH). A decrease in the levels of α-tocopherol, total ascorbic
acid and reduced glutathione was found in schizophrenics compared to normal controls. Further a significant rise in oxidative
stress and decreased antioxidant status was observed in the chronic stage of schizophrenia as compared to those in acute condition.
A significant rise in dehydroascorbic acid with concomitant fall in reduced ascorbic acid suggests scavenging action of ascorbic
acid and its utilization with increased oxidative stress as indicated by high blood malondialdehyde levels. Leucocyte ascorbic
acid, a better index of ascorbic acid status was also found to be reduced in schizophrenics, suggesting depletion of body
stores of ascorbic acid and the condition worsened with advancing age. 相似文献
25.
26.
Madhusudhana Rao A Anand U Anand CV 《Indian journal of clinical biochemistry : IJCB》2011,26(1):28-31
Numerous lines of evidence implicate a role of myeloperoxidase (MPO) in the pathogenesis of cardiovascular disease (CVD).
It is a well accepted fact that patients with chronic kidney disease (CKD) are at an increased risk for CVD. MPO is a pro-oxidant
enzyme which could be involved in the increased susceptibility of these patients to CVD. Hence, the levels of plasma MPO was
determined in healthy controls as well as in patients with CKD [stratified with the level of their kidney failure as CKD stages
II–V (end stage renal disease)]. Plasma MPO was assayed by a spectrophotometric method. Serum urea and creatinine were estimated
on a clinical chemistry analyzer using standard laboratory procedures. The mean plasma MPO levels were significantly lower
with advancing stages of renal failure (P < 0.001). There was a positive correlation between MPO and GFR (r = +0.89, P < 0.001) and a negative correlation with urea (r = −0.85, P < 0.001) and creatinine (r = −0.82, P < 0.001). While an inverse association was observed between plasma MPO and urea in CKD patients, such an association was
not observed in control subjects (P = 0.43). In conclusion, the decline in plasma MPO levels may be due to the inhibitory effect of uraemic toxins on the enzyme. 相似文献
27.
A. K. Pradhan A. K. Shukla M. V. R. Reddy N. Garg 《Indian journal of clinical biochemistry : IJCB》2004,19(1):83-87
Oxidative stress was assesed by estimating lipid peroxidation product (LPO) in the form of thiobarbituric acid reactive substances
(TBARS), enzymatic antioxidants in the form of superoxide dismutase (SOD), catalase and nonenzymatic antioxidant vitamins
e.g. vitamin C, β carotene and vitamin E in either serum or plasma or erythrocytes in 190 cases of age related cataract in
the age group of 50–80 years. 190 cases were grouped into three morphological types namely, 73 cases of cortical, 77 cases
of posterior subcapsular and 40 cases of nuclear cataract and values of LPO and antioxidants were compared with 78 cases of
age matched healthy control groups. Plasma TBARS levels were cataract cases when compared with control groups. There were
no significant differences in the erythrocyte levels of catalase and plasma levels of Vit E between cataract cases and control
groups. No significant changes of parameters were seen among three different morphological types of age related cataract.
The present study shows that the oxidative stress may play an important role in the age related cataract. 相似文献
28.
我国高校教师压力随着经济实力的增长,和教学改革的推进而不断增大,原因来自于社会、学校和自身各方面,本文主要通过与瑞典高校教师的压力的比较,吸取国外优秀的经验,解决我国对前存在的教师压力问题。 相似文献
29.
水分胁迫对黄淮海夏玉米农业气候资源利用的影响——水分胁迫对叶片生产力影响 总被引:2,自引:0,他引:2
文章对水分胁迫的夏玉米光合生产力变化进行了系统观测和实验 ,研究表明 :①可将土壤持水量的 4 0 6 89%~ 5 5 79%和 79 99%作为叶片缺水及最适的外部形态指标 ;②干旱可以使株高低 2 2 5 6 %左右 ,而短时间内水分一直维持在田间持水量水平 ,对玉米的株高影响并不大 ;③比叶重随土壤湿度增加而增大 ,到田间持水量的 79 9%时达到最大值 ,随着湿度的进一步增加 ,比叶重反而略微变小 ;④叶片含水量与土壤湿度成正相关 ,吸收辐射率则受叶片湿度与厚度的影响 ,当土壤湿度达到持水量的 79 99%时 ,叶片吸收辐射率可达到 80 %左右。在此研究基础上 ,给出了包含浓度、辐射强度、温度及土壤水分因子的夏玉米叶片生产力计算公式 ,为进一步准确推算水分胁迫对区域生产力的可能影响 ,为当地政府开发农业气候资源提供了前提条件。 相似文献
30.
M. Maneesh Sanjiba Dutta Amit Chakrabarti D M Vasudevan 《Indian journal of clinical biochemistry : IJCB》2007,22(1):138-142
Infertility is well-established harmful effect in chronic alcoholism and so far, there is no effective treatment for this
condition. The study was conducted to determine the effects of alpha tocopherol on ethanol induced testicular injuries in
male albino rats of Wistar strain. Five groups (n=6) of animals were used. Group I served as control. Group II received daily
1.6g ethanol/kg body weight/day for 4 weeks orally. Group III received 1.6g ethanol+80mg alpha tocopherol/kg body weight/day
for four weeks orally. Group IV received 1.6g ethanol/kg body weight for/day 4 weeks and followed by 80mg alpha tocopherol/kg
body weight/day for four weeks orally. Group V received 1.6g ethanol/kg body weight/day orally for 4 weeks, followed by 4
weeks abstinence. Twently-four hours after the last treatment the rats were sacrificed using anesthetic ether. Testes were
removed and used for the estimation of extent of lipid peroxidation and tissue levels of antioxidants and steroidogenic enzymes.
Alpha tocopherol treatment increased the activities of testicularΔ
5, 3β-HSD. Moreover, the treatment was also associated with significant decrease in testicular oxidative stress. Ethanol-induced
oxidative stress and decreased steroidogenesis can be reversed by treatment with alpha tocopherol. 相似文献