计算机基础实践教学改革初探

加强实践教学,培养学生创新能力是高等教育教学改革的一个重要组成部分。本文结合我校计算机基础实践教学现状,提出了建立分层次计算机基础实践教学体系的方案。该方案的顺利实施对我校计算机基础实践教学的改革具有一定的现实意义。     

Improvement of biomolecular methods for the identification and typing of Escherichia coli O157:H7 isolated from raw meat

The aim of the study was to evaluate the sensitivity of two m-PCR methods for the quantitative determination of E. coli O157:H7 in foodstuffs. Genomic serotyping was carried out on bacterial cultures, and the necessary time was optimized to increase the resolution of the method. Subsequently, artificial contamination trials using meat were conducted to assess method accuracy in foodstuffs and pursue the genetic typing of pathogens. Measurement thresholds were shown to range between 10⁵ and 10⁶ CFU/mL, but were reduced by four logarithmic cycles in 80% of samples. Relative to the meat contamination trials, serotypes were identified after 24 hours, corresponding to 10 CFU/mL inoculum, with higher rates seen when m-TSB was used for enrichment. Inoculated samples were found to contain three virulence factors (hlyA, eaeA, and stx1).

     

The pharmacokinetics of promethazine after intravenous administration in camels

The pharmacokinetics of promethazine were determined in seven camels (Camelus dromedarius) after an intravenous dose of 0.5 mg kg body weight.-1 The data obtained (median and range) were as follows: the elimination half-life (t1/2 beta) was 5.62 (2.84-6.51) h; the steady state volume of distribution (Vdss) was 8.90 (7.10-12.00) L kg-1, total body clearance (CT) was 24.5 (17.22-33.65) ml kg-1 min-1 and renal clearance (Clr) was 4.81 (1.97-5.48) ml kg-1 min-1.     

Effects of Several Procedures of Ovarian Stimulation on Reproductive Efficiency in Artificially Inseminated Does

Veterinary Research Communications -     

Effect of Oil Overlay on Inhibition Potential of Roscovitine in Sheep Cumulus‐Oocyte Complexes

Inhibitors of cyclin‐dependent kinases, as roscovitine, have been used to prevent the spontaneous resumption of meiosis in vitro and to improve the oocyte developmental competence. In this study, the interference of oil overlay on the reversible arrest capacity of roscovitine in sheep oocytes as well as its effects on cumulus expansion was evaluated. For this, cumulus‐oocyte complexes (COCs) were cultured for 20 h in TCM 199 with 10% foetal bovine serum (Control) containing 75 μm roscovitine (Rosco). Subsequently, they were in vitro matured (IVM) for further 18 h in inhibitor‐free medium with LH and FSH. The culture was performed in Petri dishes under mineral oil (+) or in 96 well plates without oil overlay (?) at 38.5°C and 5% CO₂. At 20 and 38 h, the cumulus expansion and nuclear maturation were evaluated under stereomicroscope and by Hoechst 33342 staining, respectively. No group presented cumulus expansion at 20 h. After additional culture with gonadotrophins, a significant rate of COCs from both Control groups (+/?) exhibited total expansion while in both Rosco groups (+/?) the partial expansion prevailed. Among the oocytes treated with roscovitine, 65.2% were kept at GV in the absence of oil overlay while 40.6% of them reached MII under oil cover (p < 0.05). This meiotic arrest was reversible, and proper meiosis progression also occurred in the Control groups (+/?). So, the culture system without oil overlay improved the meiotic inhibition promoted by roscovitine without affecting the cumulus expansion rate or the subsequent meiosis progression.     

西部高校计算机基础教学改革研究

计算思维是当前国内外计算机教育研究的热点。计算机基础课程的教学目标是培养学生应用计算机解决本专业的实际问题的能力。针对目前教学中存在的诸多问题,本文提出在大学计算机基础课程采用分类、分层次和模块化相结合的教学模式,并对模块的划分、模块化教学方式、模块化考核、完善辅助教学平台、开展以赛促学和举办计算机技能讲座等教学改革措施进行了论述,以期能为西部高校计算机基础教学改革提供思路。     

Hepatitis E in southern Vietnam: Seroepidemiology in humans and molecular epidemiology in pigs

Viral pathogens account for a significant proportion of the burden of emerging infectious diseases in humans. The Wellcome Trust‐Vietnamese Initiative on Zoonotic Infections (WT‐VIZIONS) is aiming to understand the circulation of viral zoonotic pathogens in animals that pose a potential risk to human health. Evidence suggests that human exposure and infections with hepatitis E virus (HEV) genotypes (GT) 3 and 4 results from zoonotic transmission. Hypothesising that HEV GT3 and GT4 are circulating in the Vietnamese pig population and can be transmitted to humans, we aimed to estimate the seroprevalence of HEV exposure in a population of farmers and the general population. We additionally performed sequence analysis of HEV in pig populations in the same region to address knowledge gaps regarding HEV circulation and to evaluate if pigs were a potential source of HEV exposure. We found a high prevalence of HEV GT3 viral RNA in pigs (19.1% in faecal samples and 8.2% in rectal swabs) and a high HEV seroprevalence in pig farmers (16.0%) and a hospital‐attending population (31.7%) in southern Vietnam. The hospital population was recruited as a general‐population proxy even though this particular population subgroup may introduce bias. The detection of HEV RNA in pigs indicates that HEV may be a zoonotic disease risk in this location, although a larger sample size is required to infer an association between HEV positivity in pigs and seroprevalence in humans.     

基于Matlab的幅度调制信号仿真研究

通信系统的仿真是研究通信系统性能的有效手段，很多通信理论比较抽象不易理解，而利用Matlab进行仿真把抽象的东西形象化，便于深刻理解。本文在介绍幅度调制原理的基础上，利用Matlab／Simulink工具箱，对模拟幅度调制系统——常规双边带调幅（AM）、抑制载波双边带调幅（DSB-SC）、单边带调幅（SSB）进行了仿真实现。