The design parameters and the operational aspects ofmine water disposal project in Fengxi Xinyu coalmine were *** primary disposal process included neutralization,coagulation settling and mechanical filtration process...
详细信息
The design parameters and the operational aspects ofmine water disposal project in Fengxi Xinyu coalmine were *** primary disposal process included neutralization,coagulation settling and mechanical filtration process,and reverse osmosis (RO) process for desalination were used to treatmine water with high-turbidity,high-hardness and *** results showed that the pretreatedmine water could be used for washing coal,and the quality of permeate liquid of RO for water with milk excelled the national standards for drinking *** water source was supplied to the coalmine,the recycle ofmine water was resource engineering practice.
We examined the temporal factors of postconditioning, assessed whether gradual reperfusion reduces infarcts, and compared postconditioning's protection with that of both rapid and delayed preconditioning. Focal is...
详细信息
We examined the temporal factors of postconditioning, assessed whether gradual reperfusion reduces infarcts, and compared postconditioning's protection with that of both rapid and delayed preconditioning. Focal ischemia was generated by permanent occlusion of the left distal middle cerebral artery (dMCA) combined with 30 min of occlusion of both common carotid arteries (CCA) in rats. Postconditioning was performed by repetitive brief release and occlusion of CCA after 30 min of CCA occlusion. Gradual reperfusion was generated by controlled release of the bilateral CCA. We confirmed that postconditioning disrupted the early reperfusion but improved cerebral blood flow (CBF) thereafter. Postconditioning with three cycles, but not with 10 cycles, of 30 sec CCA release and 10 sec CCA occlusion (30s/10s) reduced infarction measured at 2 days after stroke. In addition, postconditioning with 10 cycles, but not with three cycles, of 10s/10s reduced infarction but it lost protection when initiated at 3 min after reperfusion. In addition, gradual reperfusion also reduced infarction. Moreover, both rapid and delayed preconditioning conducted 60 min and 3 days before stroke reduced infarct sizes. However, no additional protection was detected when postconditioning was combined with either rapid or delayed preconditioning. In conclusion, gradual reperfusion reduced infarction;postconditioning's protection depended on the number of cycles and duration of each cycle of reperfusion and occlusion and the onset time of postconditioning;postconditioning's protection was comparable to that of rapid preconditioning but not as robust as that of delayed preconditioning. (c) 2008 Wiley-Liss, Inc.
We previously reported that ischemic postconditioning with a series of mechanical interruptions of reperfusion reduced infarct volume 2 days after focal ischemia in rats. Here, we extend this data by examining long-te...
详细信息
We previously reported that ischemic postconditioning with a series of mechanical interruptions of reperfusion reduced infarct volume 2 days after focal ischemia in rats. Here, we extend this data by examining long-term protection and exploring underlying mechanisms involving the Akt, mitogen-activated protein kinase (MAPK) and protein kinase C (PKC) signaling pathways. Post-conditioning reduced infarct and improved behavioral function assessed 30 days after stroke. Additionally, postconditioning increased levels of phosphorylated Akt (Ser473) as measured by western blot and Akt activity as measured by an in vitro kinase assay. Inhibiting Akt activity by a phosphoinositide 3-kinase inhibitor, LY294002, enlarged infarct in postconditioned rats. Postconditioning did not affect protein levels of phosphorylated-phosphatase and tensin homologue deleted on chromosome 10 or -phosphoinositide-dependent protein kinase-1 (molecules upstream of Akt) but did inhibit an increase in phosphorylated-glycogen synthase kinase 3 beta, an Akt effector. In addition, postconditioning blocked beta-catenin phosphorylation subsequent to glycogen synthase kinase, but had no effect on total or non-phosphorylated active beta-catenin protein levels. Furthermore, postconditioning inhibited increases in the amount of phosphorylated-c-Jun N-terminal kinase and extracellular signal-regulated kinase 1/2 in the MAPK pathway. Finally, postconditioning blocked death-promoting delta PKC cleavage and attenuated reduction in phosphorylation of survival-promoting epsilon PKC. In conclusion, our data suggest that postconditioning provides long-term protection against stroke in rats. Additionally, we found that Akt activity contributes to postconditioning's protection;furthermore, increases in epsilon PKC activity, a survival-promoting pathway, and reductions in MAPK and delta PKC activity;two putative death-promoting pathways correlate with postconditioning's protection.
Dephosphorylated and activated glycogen synthase kinase (GSK) 3 beta hyperphosphorylates beta-catenin, leading to its ubiquitin-proteosome-mediated degradation. beta-catenin-knockdown increases while beta-catenin over...
详细信息
Dephosphorylated and activated glycogen synthase kinase (GSK) 3 beta hyperphosphorylates beta-catenin, leading to its ubiquitin-proteosome-mediated degradation. beta-catenin-knockdown increases while beta-catenin overexpression prevents neuronal death in vitro;in addition, protein levels of beta-catenin are reduced in the brain of Alzheimer's patients. However, whether beta-catenin degradation is involved in stroke-induced brain injury is unknown. Here we studied activities of GSK 3 and beta-catenin, and the protective effect of moderate hypothermia (30 degrees C) on these activities after focal ischemia in rats. The results of Western blot showed that GSK 3 beta was dephosphorylated at 5 and 24 h after stroke in the normothermic (37 degrees C) brain;hypothermia augmented GSK 3 beta dephosphorylation. Because hypothermia. reduces infarction, these results contradict with previous studies showing that GSK 3 dephosphorylation worsens neuronal death. Nevertheless, hypothermia blocked degradation of total GSK 3 beta protein. Corresponding to GSK 3 activity in normothermic rats, beta-catenin phosphorylation transiently increased at 5 h in both the ischemic penumbra and core, and the total protein level of-catenin degraded after normothermic stroke. Hypothermia did not inhibit beta-catenin phosphorylation, but it blocked beta-catenin degradation in the ischemic penumbra. In conclusion, moderate hypothermia can stabilize beta-catenin, which may contribute to the protective effect of moderate hypothermia. (c) 2008 Elsevier B.V. All rights reserved.
The effect of IF (Intermediate Frequency) analog AGC on QPSK/OQPSK signal detection is evaluated for LEO satellite system where Doppler drift, large dynamic range of signal power and low Eb/No condition are difficult ...
详细信息
The effect of IF (intermediate frequency) analog AGC on QPSK/OQPSK signal detection is evaluated for LEO satellite system where Doppler drift, large dynamic range of signal power and low Eb/No condition are difficult ...
详细信息
The effect of IF (intermediate frequency) analog AGC on QPSK/OQPSK signal detection is evaluated for LEO satellite system where Doppler drift, large dynamic range of signal power and low Eb/No condition are difficult to deal with. The way of setting reference value of logarithmic power based AGC is discussed. Coherent accumulation and non-coherent accumulation are used for detecting, while signal's PDF and performance vs. accumulation times are derived mathematically. Experiment shows that with 60 KHz Doppler offset, Eb/No=0dB under QPSK/OQPSK, only 16 bits was consumed to detect the signal with 99.9% detection probability and 0.1% false alarm probability.
暂无评论