Intramammary infusion of an Enterococcus faecium SF68 preparation promoted the involution of drying off Holstein cows partly related to neutrophil‐associated matrix metalloproteinase 9

A problem for dairy cows following milk stasis is to cope with a high risk of intramammary infection and there is a need to initiate an extensive renewal of secretory modules in mammary glands so that milk production in next lactation may be optimized. We recently reported that ultrasonicated Enterococcus faecium SF68 (SF68) is compatible with cow mammary glands and an enhancer of innate immunity during the immediate post‐milk stasis period. The current study further examines the concomitant effect of ultrasonicated SF68 on mammary tissue remodeling. Four Holstein cows each received intramammary infusions of regular antibiotic dry‐cow formula (positive control) and two different doses of SF68 in different quarters. Analyses of individual quarter secretion samples showed faster neutrophil infiltration, earlier modifications in protein composition, including caseins and lactoferrins, as well as more prompt elevation of the specific unit of 92‐kDa matrix metalloproteinase 9 (MMP9) in SF68‐infused quarters compared to the positive controls. Intramammary infusion of ultrasonicated SF68 seems able to accelerate the regression of mammary synthetic capacity and potentiate the breakdown of glandular extracellular matrix, indicating a more efficient mammary gland involution. Correlation analyses imply that the ability of ultrasonicated SF68 to induce faster neutrophil chemotaxis and the associated MMP9 release is partly responsible.     

基于双变量同化和交叉小波变换的冬小麦单产估测

为进一步提高陕西省关中平原冬小麦产量估测的精度,利用集合卡尔曼滤波算法(EnKF)将CERES-Wheat模型模拟的0～20 cm土壤含水率和叶面积指数(LAI)与遥感观测的条件植被温度指数(VTCI)和LAI进行同化,同时利用交叉小波变换分析冬小麦各生育时期同化VTCI和LAI与产量之间的共振周期,通过计算小波互相关度获得各生育时期同化VTCI和LAI的权重,进而构建基于加权VTCI和LAI的冬小麦单产估测模型。结果表明,在样点尺度,经过EnKF同化的VTCI和LAI能够综合表达模型模拟值和遥感观测值的变化趋势;在区域尺度,无论是否同化,经过交叉小波变换的各生育时期VTCI和LAI分别与产量之间存在特定的共振周期,同时发现,同化有助于对关键生育时期的特征提取;相较于未同化构建的估产模型,经过同化构建的估产模型的归一化均方根误差为13.23%,决定系数为0.50,平均相对误差为10.58%,精度略有提升,且估测产量的分布与统计产量的分布更为一致,因此认为将同化与交叉小波相结合构建的双变量单产估测模型精度更高,可为进一步实现高精度的区域产量估测提供研究基础。     

Induction of glucokinase mRNA by dietary phenolic compounds in rat liver cells in vitro

Diabetes and its complications, including oxidative stress, are major reasons for medical intervention and one of the most frequent causes of death in developed countries. Several lines of data suggest that the use of certain dietary polyphenolic compounds may alter glucose metabolism, thus decreasing the risk for type 2 diabetes. In this paper, we present the effect of phenolic acids (caffeic, chlorogenic, rosmarinic, and ferulic) and extracts from Smallanthus sonchifolius and Prunella vulgaris on glucose production in rat hepatocytes and on glucokinase, glucose-6-phosphatase, and phosphoenol-pyruvate carboxykinase mRNA expression in rat hepatoma Fao cells. The phenolics at 500 microM and after 1 h incubation lowered glucose production via both gluconeogenesis (10 mM alanine or dihydroxyacetone as precursors) and glycogenolysis compared with metformin. Most of the phenolics increased the level of glucokinase mRNA after 24 h in the same way as insulin (10(-7) M).     

亚麻纤维脱胶技术及在复合材料领域的应用与研究进展

亚麻(Linum usitatissimum L.)是一种古老的作物,在人类历史上扮演着重要的角色。为了研究亚麻纤维作为可再生材料在生产生活中的应用,综述了亚麻纤维的生物学特性、亚麻纤维脱胶方法与表面改良技术的最新研究进展及其在复合材料领域中的应用,探讨了亚麻纤维的应用前景,旨在为亚麻相关的研究提供理论基础。     

油松建筑材密度管理图的编制及其应用

针对建筑材目的油松人工林经营措施,探讨不同生长发育阶段油松人工林密度调控下蓄积变化,为森林可持续经营提供科学依据。对河北平泉阳坡中土、阴坡中土和阴坡厚土3种主要立地类型的全生命周期油松人工林编制密度管理图,得出培育小、中、大径级建筑材措施。结果表明:河北油松建筑材林的培育,阳坡中土培育小径材、阴坡中土和阴坡厚土培育中大径材,期间经过2~3次间伐以达到高效培育的目的。阳坡中土林分,初植密度3 000~3 300株/hm2,10年生间伐强度12%,15年生强度20%,25年生强度25%,主伐时树高级为9~11 m,培育小径材。阴坡中土林分,初植密度2 700~3 000株/hm2,9年生间伐强度25%,19年生强度30%,主伐时树高级为9~11 m,培育中径材;初植密度2 200~2 500株/hm2,9年生间伐强度20%,17年生强度25%,27年生强度30%,主伐时树高级为11~13 m,培育大径材。阴坡厚土林分,初植密度2 000~2 300株/hm2,7年生间伐强度20%,15年生强度30%,主伐时树高级为11~13 m,培育中径材;初植密度1 000~1 200株/hm2,7年生间伐强度20%,13年生强度20%,23年生强度25%,主伐时树高级为13~15 m,培育大径材。     

Effects of crushed conspecifics on growth and survival of Penaeus monodon Fabricius post larvae

In the present study, the hypothesis tested was that Penaeus monodon post‐larvae (PL) experience lower growth when exposed to crushed conspecifics, which was achieved by exposing individual P. monodon PL with abundant food for 4 weeks to a gradient from 0 to 100 crushed conspecific PL L^?1. Both dry weight (48.5±7.2 mg) and body size (28.0±1.3 mm) of animals exposed to 1 macerated PL L^?1 were significantly (P≤0.011) higher than those of animals in treatments with 0, 5 and 10 crushed PL L^?1 (average over treatments: 25.6±3.2 mg; 23.4±0.5 mm). All animals died within 1 week when exposed to 70 and 100 crushed PL L^?1, and within 3–4 weeks when exposed to 50 and 30 crushed PL L^?1. Exposure time affected mortality and it appeared that LC₅₀ values decreased from 60 to 13 crushed PL L^?1 from 1 to 4 weeks' exposure. Survival of P. monodon PL was negatively correlated to pH, biological oxygen demand, ammonia and nitrate. In conclusion, low dose of crushed conspecifics has a stimulatory effect on P. monodon PL, as larvae were heavier and larger, while high doses cause high mortality.     

Optimal dietary protein requirement for juvenile ivory shell, Babylonia areolate

A growth experiment was conducted to determine the optimal dietary protein requirement for juvenile ivory shell reared in indoor aerated aquaria. Six isoenergetic experimental diets using fish meal, casein and gelatin as protein sources were formulated to contain graded levels of protein (27, 33, 38, 43, 49 and 54% of dry diet, respectively). Triplicate groups of 40 shells (average weight 93.50 ± 1.70 mg) were stocked in 120-l tanks and fed to apparent satiation twice daily for 8 weeks. The results showed that the growth performance and feed utilization were significantly affected by dietary protein level (P < 0.05). Maximum weight gain, mean protein gain, specific growth rate and soft body to shell ratio occurred at 43% dietary protein level (P < 0.05). There were significant differences in protein, lipid, moisture and ash content in soft body; except that ash content in shell was not significantly affected by dietary protein level. Pepsin activity in soft body tissue significantly increased with dietary protein level up to 43%, and trypsin-like enzyme activity increased with dietary protein level up to 49%. However, lipase activity in soft body decreased with increasing dietary protein level. However, no significant differences (P < 0.05) in survival, calcium, phosphorus concentration in the shell and soft body were found among dietary treatments. Quadratic regression analysis of weight gain against dietary protein level indicated that the optimal dietary protein requirement for maximum growth and feed utilization of juvenile ivory shell is 45% of dry diet.     

海水池塘虾鱼贝蟹综合生态立体混养试验

目前,全国的对虾池综合养殖面积已发展到20万hm2以上,养殖对虾的生态环境日益改善,与海区的水交换明显减少,暴发性虾病有所控制,对虾产量逐年回升,充分显示了虾池综合养殖强大的生命力和广阔的发展前景.     

Comparison of larval performance between Thai and Vietnamese freshwater giant prawn, Macrobrachium rosenbergii (de Man): a preliminary study

This study compared the performance of larvae of giant freshwater prawn (Macrobrachium rosenbergii) from Thailand and Vietnam. Thai broods were collected from a farm and Vietnamese broods were collected from a river. Larvae from these two sources were raised in identical environments, and their rates of development and survival as well as their ability to withstand environmental stresses were assessed. The first postlarval stage was observed in both strains on day 22. All larvae (100%) from Thai broods completed metamorphosis by day 36, but only 89% of the Vietnam strain completed metamorphosis by day 45. The stages of development were more uniform in larvae from the Thai stock than the Vietnamese stock. Survival differences were observed within the first week (92% in the Thai group vs. 55% in the Vietnamese group). These differences were most pronounced beginning in week 5 (52% and 16% respectively) and week 7 (33% and 2% respectively). No clear difference was found in brood size and fecundity between the two groups. No difference in survival was observed between the two groups of larvae challenged with salinity, oxygen or formalin. Differential development rates of larvae in the same batch would naturally create conditions favourable for cannibalism and impaired ability to capture food. The earlier and more uniform rate of development, and subsequent higher rate of survival of Thai stock compared with the Vietnamese wild stock is suggested to be due to inadvertent selection in the domesticated stock.     

Experimental study on the effect of horizontal waves on netting panels

The effect of horizontal waves on flexible netting panels is examined in this study, to evaluate the testing method of pretensioned mooring, radial systems, and flexible netting structures. The netting was suspended at a specific hanging ratio for six polyethylene panels with different characteristics. The aim was to evaluate the calculation method for horizontal wave forces on flexible netting panels. A regular wave was used in the experiment, with wave period 0.8–2.0 s and wave height 50–250 mm. The force on the netting structure was recorded by a tension transducer and digital signal recorder, and was simulated by a cubic spline in terms of the wave experiment under different wave conditions. The horizontal wave force on the netting panel changed periodically and asymmetrically, which was similar to the surface wave elevation. The horizontal wave force was related to the netting panel height and width (l), wave height (H) and wave length (L), twine diameter (d) and bar length (a) of the mesh. Using dual series relations, least-squares approximation, and multiple stepwise regression analysis, the following formula was obtained for the horizontal wave average apex value (F) on the netting panel: F=0.13ρgl(H/2)²(d/a)(H ^0.64 L ^0.77/0.9a ^0.44).