五味子多糖对氧化应激损伤血管内皮细胞的保护作用

体外培养血管内皮细胞,随机分为对照组、模型组及五味子多糖低、中、高剂量（20、40、80μg/ml）组。除对照组外,其余各组培养基中加入终浓度为200μmol/L的H2O2,制备血管内皮细胞氧化损伤。通过实验得出五味子多糖对血管内皮细胞氧化应激损伤具有保护作用,其机制与提高血管内皮细胞抗氧化应激损伤能力有关的结论。     

高校“中国近现代史纲要”课程教学中的几点思考

"中国近现代史纲要"是国家为高校大学生新开设的一门思想政治理论课,是新形势下国家重视历史教育的充分体现。教师在教学过程中要把握好课程的性质、体系,利用多种教学手段,改进教学中遇到的问题,提升教学质量,实现这门课对学生的思想政治教育和爱国主义教育。     

Design of hybrid automatic repeat request （HARQ） for TDD-OFDM system

Reliability-based hybrid automatic repeat request （HARQ） （RB-HARQ） is a recently developed form of incremental-redundancy ARQ. It achieves good performance whereas large retransmission request packets should be fed back. In this paper, in order to reduce the number of the fed back bits, we propose a HARQ scheme applied in time duplex division orthogonal frequency division multiplexing （TDD- OFI）M） system over the slow fading channel which is named channel-based HARQ （CB-HARQ）. Because one bit which meets deep fading is always with small value of log likelihood ratio （LLR） during the process of decoding of LDPC code, the bits transmitted on the carrier with deep fading are retransmitted. At the receiver, the decoder will compute the locations of retransmission bits according to the channel fading values which are gotten by utilizing the feature of channel symmetry in TDD mode. So the indices of retransmission bits are avoided to be transmitted. Simulation results show that this method achieves better BER performance and requires much smaller request packets in feedback link.     

子宫内膜异位症患者腹腔液及血清TNF水平测定

探讨子宫内膜异位症(内异症)患者腹腔液及血清中肿瘤坏死因子( TNF)的变化及意义.采用酶联免疫吸附双抗体夹心法(ELISA)检测39例内异症患者(Ⅰ-Ⅱ期17例,Ⅲ-Ⅳ期22例)及16例对照组(其他妇科手术,术中可见腹腔积液者)腹腔液及血清中TNF含量.内异症组腹腔液及血清TNF含量均低于对照组,差异有统计学意义(P＜0. 05).内异症组Ⅲ、Ⅳ期腹腔液[TNF(62.37±13.7) pg/mL]和血清[TNF(53.64±17.4) pg/mL]均低于Ⅰ、Ⅱ期腹腔液[(76.38±13.5) pg/mL]和血清[75.67±12.3) pg/mL]含量,差异均有统计学意义(P均＜0. 05); 说明: TNF在内异症发病中起重要作用,检测其含量变化有利于该病的诊断和治疗.     

基于LDPC编码的水声OFDM系统设计

水声信道是目前通信环境中最为恶劣的信道,只有采用强有力的调制编码方式才可能实现高速可靠的通信.笔者提出了一种水声LDPC-OFDM系统设计方案,采用LDPC码进行纠错,并用一个均衡器消除多普勒频移引发的载波间干扰,从而提高通信质量.仿真结果表明该方案能够得到理想的增益.