Influences of sand cover on erosion processes of loess slopes based on rainfall simulation experiments

Aeolian-fluvial interplay erosion regions are subject to intense soil erosion and are of particular concern in loess areas of northwestern China.Understanding the composition,distribution,and transport processes of eroded sediments in these regions is of considerable scientific significance for controlling soil erosion.In this study,based on laboratory rainfall simulation experiments,we analyzed rainfall-induced erosion processes on sand-covered loess slopes(SS)with different sand cover patterns(including length and thickness)and uncovered loess slopes(LS)to investigate the influences of sand cover on erosion processes of loess slopes in case regions of aeolian-fluvial erosion.The grain-size curves of eroded sediments were fitted using the Weibull function.Compositions of eroded sediments under different sand cover patterns and rainfall intensities were analyzed to explore sediment transport modes of SS.The influences of sand cover amount and pattern on erosion processes of loess slopes were also discussed.The results show that sand cover on loess slopes influences the proportion of loess erosion and that the compositions of eroded sediments vary between SS and LS.Sand cover on loess slopes transforms silt erosion into sand erosion by reducing splash erosion and changing the rainfall-induced erosion processes.The percentage of eroded sand from SS in the early stage of runoff and sediment generation is always higher than that in the late stage.Sand cover on loess slopes aggravates loess erosion,not only by adding sand as additional eroded sediments but also by increasing the amount of eroded loess,compared with the loess slopes without sand cover.The influence of sand cover pattern on runoff yield and the amount of eroded sediments is larger than that of sand cover amount.Furthermore,given the same sand cover pattern,a thicker sand cover could increase sand erosion while a thinner sand cover could aggravate loess erosion.This difference explains the existence of intense erosion on slopes that are thinly covered with sand in regions where aeolian erosion and fluvial erosion interact.     

硒对母猪氧化应激及其后代抗氧化能力的营养调控研究

硒作为的重要微量元素之一,可以通过胎盘和乳组织进行转移。仔猪可以从乳汁中获取硒源,提高硒含量,进而提高仔猪的初生重。同时,硒也能够调节母猪妊娠期间代谢速度,控制妊娠期自由基产生,进而提高胎盘输送营养功能。文章从母猪氧化应激体系角度来解析硒对母猪妊娠期氧化应激的调控机制、硒对哺乳母猪生产性能的调控作用。     

光裸方格星虫的研究进展

光裸方格星虫(Sipunculus nudus)具有丰富的食用和药用价值,为给光裸方格星虫的资源保护与利用以及进一步深入研究提供参考,综述了国内外有关光裸方格星虫在种质资源、营养价值、生理结构、人工养殖技术、营养需求与饲料及环境毒理学等方面的研究进展。     

表观遗传修饰在骨骼肌细胞增殖分化过程中的研究进展

骨骼肌是肌肉的主要构成部分，骨骼肌细胞发生增殖和分化的过程都是肌肉发育的基础，直接影响着家养动物的产肉性能。研究发现表观遗传修饰作用对骨骼肌细胞增殖分化具有重要的调控作用，表明该遗传修饰作用对家养动物肌肉发育具有重大的意义。作者从DNA甲基化对骨骼肌细胞增殖分化影响、组蛋白乙酰化所含因子调控基因选择表达作用、非编码RNA调控和染色体重塑作用所起的影响等方面分别介绍了表观遗传在骨骼肌细胞增殖分化过程中的研究进展，简述了不同修饰方式和不同作用因子对骨骼肌增殖和分化两个过程的影响。同时也回顾了前人在研究骨骼肌增殖分化过程所用到的方法和手段，进而分析了表观调控作用因子在骨骼肌生长过程中所起到的作用。旨在进一步阐述表观遗传修饰在骨骼肌增殖和分化过程中所起到的重要作用，增强对骨骼肌增殖分化调控过程的了解，为和动物生产实际相结合提供参考途径，同时也为骨骼肌生长发育等分子调控提供更多参考素材。     

Effects of the severity and timing of basal leaf removal on the amino acids profiles of Sauvignon Blanc grapes and wines

The effects of the severity and timing of leaf removal(LR) on the amino acids of Sauvignon Blanc grapes and wines were studied during the 2017 growing season. High-performance liquid chromatography(HPLC) was used to analyze the amino acids profiles of grape berries and wines. The basal leaves were removed at three time points(40, 56 and 72 days after flowering, named LR40, LR56 and LR72, respectively) at two severity levels(one at which the first, third, and fifth basal leaves of each shoot were removed(50% level); and another at which the first six basal leaves were removed(100% level)). The results showed that leaf removal had little impact on total soluble solids(°Brix), titratable acidity, pH or berry weight. The LR72-50% treated grapes had higher berry weight, titratable acidity and °Brix than those of the other treatments. The highest concentrations of total amino acids and of total amino acids except proline were detected in LR72-50% treated grapes(2 952.58 and 2 764.36 mg L~(-1), respectively); the lowest were detected in LR72-100% treated grapes(2 172.82 and 2 038.71 mg L~(-1), respectively). LR72-50% treatment significantly promoted the synthesis of aspartic acid, serine, arginine, alanine, aminobutyric acid and proline at both severity levels for grapes, the concentrations of all of these amino acids were increased relative to the control concentrations. The LR72-50%, LR40-100% and LR72-100% treated wines had higher total amino acids concentrations and higher concentrations of some individual amino acids, such as arginine, alanine and serine, than did the control wines. Of all the amino acids studied, glycine, tyrosine, cysteine, methionine and lysine were not significantly influenced by the timing or severity basal defoliation in grapes and wines. The present study reveals the effects of the timing and severity of leaf removal on the amino acids profiles of grapes and wines.     

持续低温胁迫下大花蕙兰不同组织器官耐寒响应

采用自然降温处理,分别测定了大花蕙兰地上部分和地下部分中丙二醛(MDA)含量、膜透性(CMP)、可溶性蛋白质(SP)含量、可溶性糖(SS)含量、超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性和过氧化氢酶(CAT)活性等与耐寒性有关的生理指标,比较地上部分和地下部分耐寒差异性,研究低温胁迫对大花蕙兰组培苗生理特性的影响。结果表明:POD活性、可溶性蛋白质含量和可溶性糖含量在反映大花蕙兰组培苗耐寒性方面作用明显,可作为其耐寒性鉴定指标;地上部分和地下部分在耐寒性提高时表现出不一致性,后者比前者表现出更强的耐寒性能。     

柑橘溃疡病菌LAMP实时浊度检测方法的建立及应用

以柑橘溃疡病菌特异性高的假定蛋白基因（登录号：AE008923.1）为靶标，设计并筛选4条引物来特异性识别靶标序列中的6个独立区域，建立柑橘溃疡病菌LAMP实时浊度检测方法。该方法利用实时浊度仪检测反应过程中产生的焦磷酸镁白色沉淀，实现对LAMP整个反应过程的实时监控。从镁离子浓度、甜菜碱浓度、dNTPs浓度、引物浓度和反应温度5个变量参数对 LAMP检测体系进行优化，并对方法的特异性、灵敏度、稳定性及实际样品检测效果进行评价。结果显示，该体系经优化后稳定性良好，可在66 ℃ 恒温条件下，60 min内完成检测；DNA检测下限可达0.02 ng/μL，灵敏度与荧光定量PCR方法相同，比常规PCR方法高1个数量级；能快速、准确地对田间疑似样品进行检测，与荧光定量PCR方法的检出情况一致，没有漏检。结果说明柑橘溃疡病菌实时浊度LAMP检测方法操作简便、所需时间短，特异性与灵敏度高，为柑橘溃疡病菌的快速筛查提供较好的途径。     

白花蛇舌草超微粉对小鼠免疫功能的影响

The assay was aimed to study the effect of Hedyotis diffusa Willd superfines powder on immune function. Three groups of mice were gavaged with the drugs at doses of 1.75,1.25 and 0.75 g/kg once a day for 7 consecutive days, repectively. The mice of control group were administered with the same volume of saline.At the last time, mice were injected into the muscle with Newcastle disease vaccine,and get peripheral blood on days 7, 14 and 21 after the medicine administration. The enhancement of innate immune responses were evaluated by using CCK-8 method, hemagglutination inhibition test, macrophage phagocytic function test and organ coefficient method. The levels of lymphocytes proliferative capacity, serum antibody, peritoneal macrophage phagocytosis and the indexes of immune organs in mice were extremely significantly enhanced (P＜0.01). Hedyotis diffusa dWilld superfines powder could extremely significantly regulate the immunity function of mice (P＜0.01).     

血吸虫疫苗研究现状和发展方向

血吸虫疫苗的研究工作已经进行了很长一段时间,发现了一批有价值的候选疫苗分子。同时通过改进和优化免疫途径,血吸虫疫苗的免疫保护力正在逐步提高。随着研究的日益深入,对血吸虫疫苗的免疫机制等了解更加透彻,距离研制出能诱导高的、稳定的免疫保护力的疫苗分子的目标将越来越近。     

切割叶轮以解决加热站循环泵电机过载问题

针对加热站循环泵存在过载的问题,提出了切割叶轮的解决方法,并进行了现场实施.实践证明所提出的方法是成功的,为电厂的冬季采暖安全、稳定和经济运行带来了可观的效益.