HSP27 and αB-crystallin are highly up-regulated in corpus uteri myometrium at labor

［ABSTRACT］AIM: To investigate the expression of heat-shock protein 27 (HSP27) and α-cystallin B chain (αB-crystallin) proteins in corpus uteri myometrium in not-in-labor and in-labor situations.METHODS: Comparative proteomics technique was used to identify HSP27 and αB-crystallin in corpus uteri myometrium in not-in-labor and in-labor situations. The methods of half quantitative RT-PCR, Western blotting analysis and immunohistochemistry were performed to determine the differential expression levels of HSP27. RESULTS: The protein levels of HSP27 and αB-crystallin were highly up-regulated in corpus uteri myometrium at term spontaneous labor (P<0.05). Four HSP27 spots were identified with identical molecular weight and different isoelectric points from 2 two-dimensional gel electrophoresis profiles of corpus uteri myometrium. ImageMaster 2D Platinum software analysis showed that only one HSP27 spot had differential significance (P<0.05),and the rest spots had no significant difference between the 2 profiles (P>0.05). CONCLUSION: The protein levels of HSP27 and αB-crystallin are highly up-regulated in corpus uteri myometrium at term spontaneous labor, suggesting that the two small heat-shock proteins participate in human myometrial contraction at labor and will be potential targets for future tocolytic design.     

Effects of Temperature Changes on the Contractility of Isolated Small Intestinal Smooth Muscle in Rabbits

In order to explore the influence of temperature changes on animal digestive tract smooth muscle,the contractility of isolated rabbit small intestine (duodenum,jejunum and ileum) were measured at different temperatures (39→32℃,32→39℃,39→42℃ and 42→39℃) using the biological signal processing system.The results showed that the contraction frequency of duodenum and jejunum was positively correlated with temperature changes between 39 and 32℃,while the amplitude and tension of duodenum were negatively correlated with temperature changes.Only the contraction frequency of ileum was positively correlated with temperature changes between 39 and 32℃.Changes of frequency,amplitude and tension of duodenum between 39 and 42℃ were similar with those changes between 39 and 32℃.However,the contraction of jejunum and ileum was irregular.When the temperature was decreased from 42 to 39℃,the contraction of small intestine could not return to the condition in 39℃.The results suggested that the optimal bath temperature was 37℃ in contraction test of rabbit small intestine in vitro,and the present results could be referenced to explore the disorder of gastrointestinal movement due to the change of environment temperature in animals.     

Determining fertilizer phosphorus requirement of upland rice

Abstract

Assessing the fertilizer phosphorus requirement (FPR) of crops is an important component of research for efficient and rational use of fertilizers. Soil and plant tests are used to determine the FPR of crops. Two methods were evaluated for determining the FPR of upland rice grown on an Ultisol in the humid forest zone of Cote d'Ivoire. The first method used a simple model based on P uptake using the equation: FPR=(Up‐U0)/PRF, where Up is P uptake at a given yield, Uo is P uptake from unfertilized soil, and PRF is the P recovery fraction of applied P. The parameters, U0, Up, and FPR were determined in field experiments for the rice cultivars grown on an Ultisol under rainfed upland conditions. The second method was based on the P applied, P uptake, and grain yield relationships for upland rice. First, P uptake at a given rice yield was determined from the relationship between total P uptake and grain yield. The amount of fertilizer P applied for the given P uptake and grain yield was then, determined from the relationship between P applied and P uptake. There was a good agreement between the observed values of FPR and the predicted values of FPR determined by the two methods. The results suggest that the simple model based on P uptake can be utilized for determining the fertilizer P requirements of crops.     

皮带张紧轮式离合器反求分析

以德国CLAAS联合收割机割台传动皮带张紧轮式离合器为反求对象,运用反求工程技术,分析了其设计意图和工作原理,实测了弹簧的技术参数,进行了动力分析。反求结果表明:弹簧能自动调节张紧轮位置,以适应V带小幅度的变形;动力传动可靠、有效,可以在农业机械中借鉴和使用。     

农药药液物理性质对雾滴空间运行规律的影响模拟研究

研究农药雾滴的空间运行规律及其影响因素,对减少飘移、保护环境及助剂开发都有重要意义。选取2%甲氨基阿维菌素苯甲酸盐(简称甲维盐)乳油,采用Euler-Lagrange离散相模型对雾滴空间运行过程进行数值模拟,分析了农药雾滴的空间运行轨迹。结果表明:黏度和表面张力对雾滴空间运行规律的影响主要作用于喷头出口处的雾化过程,雾化过程的结果决定了后续雾滴空间运行的轨迹和飘移率。药液黏度和表面张力越大,出口处大粒径雾滴所占的比例越高,雾滴的平均粒径和空间运行速率相应增大,在空间运行过程中停留时间缩短,飘移率降低。确定了标准条件下黏度和表面张力调控的适宜范围:黏度在0.001~0.01 Pa·s之间,飘移率为18.77%~12.67%;表面张力在0.042~0.060 N/m之间,飘移率为38.93%~24.40%。针对实际场景,提出了调控药液物理性质的具体方案:通过将2%甲维盐乳油的黏度和表面张力分别增大至0.01 Pa·s和0.060 N/m,可以分别将4 m/s和5 m/s风速条件下的飘移率降低18%和43%,从而有效降低了农药雾滴的飘移损失。     

Hydrodynamic responses of longline aquaculture facility with lantern nets in waves

To prevent occurrences of structure failure, it is essential to study the mooring line tension and motions of the longline aquaculture facilities with lantern nets. This study describes a physical model experiment that attempts to determine an optimal structure design. The experiment investigated effects of three facility design factors on the mooring line tension and movement of the lantern net and mainline: incident wave angles, lantern net layout depths, and lantern net layout forms (horizontal arrangement/staggered arrangement). The experimental results indicate that the mooring line tension decreases with increasing wave periods. The amplitude and variation of windward mooring line tension are much larger and more complex than that of leeward. The vertical movement amplitude and variation range of the lantern net and mainline are much larger than that of horizontal movement amplitude. Decreasing the incident wave angle, deepening the arrangement depth of lantern nets or adopting staggered arrangement can reduce the mooring line tension in the case of longer wave period. The analysis indicates that increasing the layout depths of the lantern nets and applying the staggered layout form are beneficial in reducing the vertical motion amplitude and elliptical excursion of the mainline. The incident wave angle has a relatively weak effect on the motion of the main and lantern net. Increasing the layout depths of lantern nets will reduce the horizontal and vertical movement amplitudes and elliptical excursion of the lantern nets. Changing the layout forms of the lantern nets from horizontal to staggered will increase the horizontal motion amplitude and decrease the vertical motion amplitude and elliptical excursion of the lantern nets.     

基于聚乙烯木塑复合材的水披覆转印法装饰

为提高水披覆转印法装饰的聚乙烯(PE)木塑复合材表面装饰效果和附着力,从分析水披覆转印膜正反面的接触角、润湿速率入手,结合等离子体处理手段,探究了处理时间、表面张力、附着力等因素对转印效果的影响,得出基于PE木塑复合材的水披覆转印法装饰最佳工艺过程及参数。结果表明:正面润湿速率较小而反面润湿速率较大的转印膜转印效果较佳;等离子体处理时间为15 min最佳,PE木塑基材表面和底漆面的表面张力分别提高至48、46 mN·m~(-1),木塑表面的漆膜附着力可达0级;经转印膜装饰后的PE木塑表面带有实木纹理,色泽饱满,明显改善了装饰性和实用性。     

Experimental verification of bandsaw roll-tensioning theory

The validity of a bandsaw roll-tensioning theory developed by the author is verified based on a model experiment. It is shown that the actual roll-tensioning process can be clearly explained by this theory. Roll-stretching force transmission coefficients are introduced in this theory. These coefficients, which indicate the magnitude of the compression force parallel to the bandsaw surface at the roll-stretching position, are affected by the thickness of the bandsaw blade, the radius of the bandsaw blade vent at the measurement of tension, and the straightness of the bandsaw blade at the measurement of crown back, among others. For the practical use of this theory, therefore, it is necessary to determine the proper magnitude of these coefficients based on tensioning experiments.     

CYLINDRICAL BENDING PROBLEM OF RECTANGULAR PLATES STIFFENED ON ONE SIDE ALONG ONE DIRECTION WITH ELASTIC SUPPORTS AND TENSILE FORCES

On the basis of the calculated results of accurate analytic solution of stiffened rectangular plates,the general equations of cylindrical bending of the plates with tensile forces are established for engineering practice.Its solution combining with engineering problem is given for the special defor-mation conditions of elastic supports.In the paper,the numerical example is given and compared with references,it shows that the results are available.     

Closed-form Analytical Solution for Beam on Elastic Foundation with Different Tension and Compression Modulus

On the basis of the theory of different modulus, the closed-form analytical solution for beams on elastic foundations with different modulus has been derived. A comparison is made between the results of the analytical solution and those calculated from the classic mechanic theories, in which the tension modulus are equal to the compression modulus. It is shown from the numerical results that the ratio of compressive modulus to tensile modulus will greatly affect the elastic characteristic values,internal forces and flexibilities. The present theory satisfies the mechanical behavior of materials. The amount of materials can be economized through rational design by using the elastic theory of different modulus.