覆膜侧渗沟灌二维入渗数值模拟研究

根据覆膜侧渗沟灌的入渗特性,利用修正Richards方程对其水分入渗过程进行数值模拟研究,结合初始条件、边界条件和相关参数采用Galerkin有限元法进行了数值求解。经验证,所建模型具有较好的稳定性和合理性,与实际结果具有较好的一致性,且模型数值计算原理简单。为进一步研究覆膜侧渗沟灌入渗特性和地表水流运移特性及灌水技术要素优化、系统管理设计奠定了基础。     

脊尾白虾甘露糖结合凝集素(MBL)基因在抗镉胁迫中的生物学功能分析

为研究Cd2+胁迫下脊尾白虾(Exopalaemon carinicauda)甘露糖集合凝集素(MBL)在肝胰腺中表达量的变化特征,本研究利用重金属镉(Cd2+)对脊尾白虾进行96 h急性毒性实验。实验共设置5组Cd2+浓度胁迫(0、0.01、0.0175、0.021和0.0278 mmol/L),分别在Cd2+胁迫后0、3、6、12、24、48、72和96 h共8个时间点取样。实时荧光定量结果显示,高浓度Cd2+(0.0175、0.021和0.0278 mmol/L)胁迫下,脊尾白虾MBL基因的表达量先呈上升趋势,在72 h达到峰值后随后下降,但各时间点表达量均与对照组存在显著性差异(P<0.01);Cd2+浓度为0.01 mmol/L时,脊尾白虾MBL基因的表达量整体呈下降趋势。进一步采用RNA技术干扰该基因表达后,发现Cd2+胁迫后的脊尾白虾个体死亡率显著增加。本研究表明,脊尾白虾MBL在应答Cd2+胁迫过程中可对机体起到一定的保护作用。     

晋西黄土区不同植被格局坡面产流产沙特征

[目的]研究不同植被格局对坡面产流产沙特征的影响,为黄土高原水资源匮乏地区坡面水土保持植被格局的优化配置提供依据.[方法]采用野外模拟降雨试验,测定5种植被格局(2种块状镶嵌格局、横条带状格局、顺坡带状格局和裸地格局)的产流产沙特征及土壤入渗特征,探讨坡面不同植被格局和破碎度对产流、产沙、入渗的影响.[结果](1)植被...     

RNA interference of endophilin A2 inhibits synaptic vesicle endocytosis in rat hippocampal neurons

AIM: To investigate the effect of endophilin A2 on synaptic vesicle endocytosis in rat hippocampal neurons.METHODS: The siRNAs for endophilin A2 isoform were designed, and the efficacy and specificity of these siRNAs were determined by Western blot. Immunostaining was performed to verify the interference efficiency of the siRNA for endogenous endophilin A2 in the hippocampal neurons. Excitatory postsynaptic currents (EPSCs) were recorded on cultured hippocampal neurons using dual whole-cell recordings by evoking the transfected presynaptic neurons in various stimulation patterns. RESULTS: The result of immunostaining in cultured hippocampal neurons demonstrated that the siRNA of endophilin A2 inhibited the expression of endogenous endophilin A2 significantly (P<0.05). The results of dual whole-cell recordings showed that no significant difference in the EPSCs amplitude evoked between endophilin A2 knockdown neurons and control was observed when stimulated at low frequency (0.1 Hz). The amplitude of normalized EPSCs evoked in endophilin A2 knockdown neurons decreased significantly for both single-train and multiple-train stimulations (P<0.05).CONCLUSION: An effective siRNA of endophilin A2 was screened out successfully. Knockdown of endophilin A2 isoform does not affect synaptic vesicle exocytosis, but inhibits synaptic vesicle endocytosis in rat hippocampal neurons.     

一种入渗模拟模型及其应用

根据实地测试数据提出了一种简便的入渗方程,并由此导出入渗速度与入渗时间的关系以及入渗速度的渐近稳定值.试验表明模型的拟合性能良好.还在理论上证明了在足够大的实用时间范围内,本方程与 Philip 入渗方程形式上是一致的.     

不同治理模式的红壤物理性质与渗透性能研究

针对长汀县河田严重侵蚀地状况，采取4种不同模式进行治理试验，10年后对土壤物理性质和渗透性能进行研究，结果表明，不同治理模式对土壤物理性质和渗透性能影响大小为模式Ⅳ＞模式Ⅱ、Ⅲ＞模式Ⅰ，严重退化地（对照地Ⅰ、Ⅱ、Ⅲ）土壤物理性质极度恶化，土壤渗透性能相当差，采用生物措施与工程措施相结合，是改善南方严重退化红壤物理性质和木壤渗透性能良好渠道。     

芒果负压渗透处理保鲜效果的研究

控制芒果表皮组织中孔隙内的真菌侵染是解决芒果保鲜的关键。常规的消毒杀菌处理,由于孔隙的汽泡阻隔作用,保鲜剂难于进入果皮孔隙而降低保鲜效果。通过负压渗透,可排除孔隙内的气泡,使保鲜剂进入果皮深层,从而增强了保鲜效果。     

RNAi抑制猪主要病毒感染的研究进展

RNA干扰(RNAi)是外源性或内源性双链RNA诱发的mRNA水平上的基因沉默机制。RNAi技术具有高效性和特异性,具有广阔的前景。将RNAi应用于许多病毒性疾病的治疗研究取得了显著的基因沉默效果,为病毒性疾病的预防和治疗开辟了一条新途径。     

Suppression of protein expression of three avian reovirus S-class genome segments by RNA interference

RNA interference was used to suppress protein expression of three S-class genome segments of avian reovirus (ARV). Viral progeny titer was successfully down-regulated by RNA interference. Suppression of S1 genome segment, which has three open reading frames, not only decreased the expression level of the structural protein σC but also reduced cell fusion and the level of Ser¹⁵-phosphorylated p53 protein caused by the nonstructural proteins p10 and p17, respectively. Suppression of S2 or S4 genome segment by RNA interference could also reduce the expression level of σA or σNS. Interestingly, suppression of σNS resulted in down regulation of the expression of other viral products. In terms of variability of different genes among viral strains and of the impact after their suppression, it seems that the viral products involved in construction of viroplasm or core particles, like σNS, are considerable choices to efficiently inhibit ARV multiplication by RNA interference. Using a GFP reporter system, it was discovered that ARV could not inhibit activated RNA interference, suggesting that RNA interference may be used in the suppression of ARV infection.     

Occupational stress,work-home interference and burnout among Belgian veterinary practitioners

There have been few formal studies on stress in veterinary surgeons and, in the rare studies available, stress is not examined jointly through the levels of job strain and job engagement, the sources of stress in the issue of work environment and the work-home interference. The authors' goal in this study was to analyse job engagement, job strain, burnout, work-home interference and job stress factors among 216 Belgian veterinary surgeons. Rural practice was compared to small animal and mixed activity. The mean job strain and job engagement level in veterinary surgeons was not higher than what we found in other working populations. However, 15.6% of the group were found to be suffering from high burnout. Rural practitioners had a lower level of job engagement than small animal veterinary surgeons. These small animal practitioners had a lower level of job strain than the mixed practitioners. The level of burnout did not differ significantly across the three types of activity. In comparison to other Belgian and Dutch workers, veterinary surgeons perceived more negative work-home interference. Bovine and mixed practitioners were the most concerned with this problem. The two most important sources of stress reported by bovine practitioners were relations to farmers and working time management (including emergencies and availability).