Objective: To observe the effects of triptolide on the proliferation,cell cycle and apoptosis of colorectal cancer cell line SW480.Methods: SW480 cells were cultured amd treated with triptolide at different concentrations.Inhibition rates of cell growth were detected with MTT assay.The changes of cell cycle and apoptosis rate were detected with flow cytometry(FCM).Rerults: MTT assay showed that triptolide in the range of 20~100 μmol/L significantly inhibited the proliferation of SW480 cells.FCM showed that no significant difference was found in apoptosis rate before and after treatment,but S phase cells increased significantly and cell cycle was obviously blocked.Conclusions: Triptolide can inhibit SW480 cell proliferation in a dose and time dependent manner,which may be a result of cell cycle arrest.
This paper describes simple and powerful process re-engineering methodologies that consist of an operations system analysis method, processes modeling tool, and simulation. This set of planning tools would benefit operations planners in carrying out their complex tasks including process description and re-engineering.
The metal oxide arrester (MOA, shortly) is installed on the line side of the substation, which is the first line of defense for the overvoltage limitation of lightning intrusion wave. In order to deeply limit the switching overvoltage and cancel the closing resistance of the circuit breaker, the arrester is replaced by the controllable metal oxide arrester (CMOA, shortly) in the new technology. The controllable switch of CMOA can be mechanical switch or thyristor switch. Thyristor switches are sensitive to the current and current change rate (di/dt) under lightning intrusion wave. If the switch cannot withstand, appropriate protective measures must be taken to ensure the safe operation of the controllable switch under this working condition. The 1000kV West Beijing to Shijiazhuang UHV AC transmission and transformation expansion project is the first project of pilot application of CMOA. CMOA were installed at both ends of the outgoing branch of Dingtai line I. In order to study the influence of lightning intrusion wave on the controllable switch of CMOA, this paper selected this project to simulate the lightning stroke on the incoming section of Dingtai line I in Beijing West substation in the process of system air closing or single-phase reclosing, and obtained the current and di/dt of the controllable switch through CMOA under this working condition. Then the performances of mechanical and thyristor control switches were checked respectively. The results showed that the mechanical switch could withstand without protective measures. The tolerance of thyristor switch to i and di/dt exceeded the limit value, and measures should be taken to protect and limit it. In this paper, the protection measures of current limiting reactor were given, and the limiting effect of the protection measures was verified by simulation and test. It could fully meet the requirements and ensure the safe operation of thyristor controllable switch.
Fractionation using concentrated phosphoric acid is a cost-effective pretreatment approach due to production of highly reactive amorphous cellulose under modest reaction conditions. Chinese white poplar biomass was used as feedstock. The effects of pretreating temperature and liquid/solid ratio of H3PO4/poplar (v/w, ml/g) on poplar fractionation, enzymatic hydrolysis efficiency (EHE), and supramolecular structural change were investigated. Only 31% (w/w, g/g) cellulose was retained in the solid phase at the higher liquid/solid ratio of 10:1 for 60 min, while 38 % cellulose was retained at 8:1. Temperature played an important role in lignin removal, xylan hydrolysis, and enzymatic hydrolysis, which may eventually influence cellulose conversion. More than 40% lignin could be removed after 60 min pretreatment at above 50 oC. A majority of the xylan hydrolysis could be detected in mixed rinsing liquid after 80 min pretreatment at 50 oC and liquid/solid ratio of 10:1. Up to 96.37% EHE could be obtained after 24 h enzymatic hydrolysis at 50 oC. The optimal pretreatment condition was 50 oC, liquid/solid ratio 8:1 (v/w), and 60 min. After pretreatment the CrI index decreased from 39.9 % to 27.7 %, suggesting a decrease of crystalline area percentage. Pyrolysis-GC-MS results of precipitated lignin indicated that nearly 48% of the lignin was phenolic, such that it can be used as a natural antioxidative material.
Transient overvoltage is an importance cause of the failures in power system. Optical technique has been developed to measure the transients in power system in a contactless mode, which has great advantages compared to traditional measuring technique based on electrical principles. To verify the on-site performances of optical technique in measuring switching transients in UHV substations, this paper presents the measurements using optical technique conducted in Yunan 1000kV substations at the moments of energizing transformer and transmission lines. With applying simplified de-coupling method, three-phase transients at two moments were clearly given.
In this letter, we propose a two-stage design method to construct memory efficient mutual information-maximizing quantized min-sum (MIM-QMS) decoder for rate-compatible low-density parity-check (LDPC) codes. We first develop a modified density evolution to design a unique set of lookup tables (LUTs) that can be used for rate-compatible LDPC codes. The constructed LUTs are optimized based on their discrepancy values and a merge function to reduce the memory requirement. Numerical results show that the proposed rate-compatible MIM-QMS decoder can reduce the memory requirement for decoding by up to 94.92% compared to the benchmark rate-compatible LUT-based decoder with generally faster convergence speed. In addition, the proposed decoder can approach the performance of the floating-pointing belief propagation decoder within 0.15 dB.
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