Characters of head of low head pump station and the pump shaft power areanalyzed. Influence of each single factor on pump shaft power is expressed as change of specificshaft power. (non-dimensional) and the probabilit...Characters of head of low head pump station and the pump shaft power areanalyzed. Influence of each single factor on pump shaft power is expressed as change of specificshaft power. (non-dimensional) and the probability density function is determined. Influences ofmultiple factors on pump shaft power are analyzed. Method of calculating none over-loadedprobability of motor by integration by successive reductions is put forward and then relationbetween power spare coefficient and none over-loaded reliability of electric motor is established.Influences of all factors on pump shaft power being considered completely; power spare coefficientsof motor are calculated in three kinds of heads (changing and unchanging), two kinds of dirty-outconditions. Electrical motor power spare coefficients should be chosen as 1.20 approx 1.44, 1.11approx 1.19, 1.09 approx.14 respectively when pump heads are 4, 7, 9.5 m. The results mean much toreasonable choose of electrical motors in large pump stations, increasing reliability of pump unitsand saving equipment investment.展开更多
The main pathological feature of Alz-heimer’s disease(AD)is the extracellular deposition ofβ-amyloid(Aβ)in the brain,which forms insoluble Aβplaques,and tau protein hyperphosphorylation in neu-rons,which forms int...The main pathological feature of Alz-heimer’s disease(AD)is the extracellular deposition ofβ-amyloid(Aβ)in the brain,which forms insoluble Aβplaques,and tau protein hyperphosphorylation in neu-rons,which forms intracellular fibrillary tangles.So far,none of the drugs targeting Aβhave been successful in the treatment of AD.Some studies have shown that brain iron deposition may be one of the important factors in AD pathogenesis;the distribution of iron deposition has been found to be consistent with the distribution of Aβsenile plaques in the brain.Effectively reducing brain iron load might therefore be a good therapeutic approach to prevent and treat AD.展开更多
The protective role of a human erythro-cyte-derived depressing factor (EDDF) on blood vessels was evaluated. The experiments were carried out on 25 male Wistar rats aged 6-8 weeks, which were divided into control (n=8...The protective role of a human erythro-cyte-derived depressing factor (EDDF) on blood vessels was evaluated. The experiments were carried out on 25 male Wistar rats aged 6-8 weeks, which were divided into control (n=8), calcium overload (n=8) and NG-L-nitro-arginine hypertensive model groups (L-NNA, n = 9), respectively. The isolated vascular ring perfusion assay, two-photon laser scanning fluorescence microscopy (TPM) and transmitted electron microscope were used to examine the effect of EDDF on vascular function and ultrastructure. Results showed that the contractile response of calcium overload rats and L-NNA rats to phenylephrine (PE) was significantly enhanced compared with that of the control (P 【 0.05), and EDDF (10-3g·mL-1) remarkably decreased the vascular contractile response of control’s and calcium overload rats (P 【 0.05), while EDDF had no effect on that of L-NNA rats. EDDF also alleviated the ultrastructural lesion of aorta VSMC in calcium overload rats by easing the abnormal in the展开更多
文摘Characters of head of low head pump station and the pump shaft power areanalyzed. Influence of each single factor on pump shaft power is expressed as change of specificshaft power. (non-dimensional) and the probability density function is determined. Influences ofmultiple factors on pump shaft power are analyzed. Method of calculating none over-loadedprobability of motor by integration by successive reductions is put forward and then relationbetween power spare coefficient and none over-loaded reliability of electric motor is established.Influences of all factors on pump shaft power being considered completely; power spare coefficientsof motor are calculated in three kinds of heads (changing and unchanging), two kinds of dirty-outconditions. Electrical motor power spare coefficients should be chosen as 1.20 approx 1.44, 1.11approx 1.19, 1.09 approx.14 respectively when pump heads are 4, 7, 9.5 m. The results mean much toreasonable choose of electrical motors in large pump stations, increasing reliability of pump unitsand saving equipment investment.
文摘The main pathological feature of Alz-heimer’s disease(AD)is the extracellular deposition ofβ-amyloid(Aβ)in the brain,which forms insoluble Aβplaques,and tau protein hyperphosphorylation in neu-rons,which forms intracellular fibrillary tangles.So far,none of the drugs targeting Aβhave been successful in the treatment of AD.Some studies have shown that brain iron deposition may be one of the important factors in AD pathogenesis;the distribution of iron deposition has been found to be consistent with the distribution of Aβsenile plaques in the brain.Effectively reducing brain iron load might therefore be a good therapeutic approach to prevent and treat AD.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 30070281)the Doctoral Foundation of Institutions of Higher Learning of China (Grant No. 2001-2002).
文摘The protective role of a human erythro-cyte-derived depressing factor (EDDF) on blood vessels was evaluated. The experiments were carried out on 25 male Wistar rats aged 6-8 weeks, which were divided into control (n=8), calcium overload (n=8) and NG-L-nitro-arginine hypertensive model groups (L-NNA, n = 9), respectively. The isolated vascular ring perfusion assay, two-photon laser scanning fluorescence microscopy (TPM) and transmitted electron microscope were used to examine the effect of EDDF on vascular function and ultrastructure. Results showed that the contractile response of calcium overload rats and L-NNA rats to phenylephrine (PE) was significantly enhanced compared with that of the control (P 【 0.05), and EDDF (10-3g·mL-1) remarkably decreased the vascular contractile response of control’s and calcium overload rats (P 【 0.05), while EDDF had no effect on that of L-NNA rats. EDDF also alleviated the ultrastructural lesion of aorta VSMC in calcium overload rats by easing the abnormal in the
