表没食子儿茶素没食子酸酯对糖尿病大鼠神经病理性疼痛的改善作用

目的探讨表没食子儿茶素没食子酸酯(EGCG)对糖尿病大鼠神经病理性疼痛的改善作用。方法将50只SD大鼠随机分为对照组、糖尿病组、10 mg/kg EGCG组、50 mg/kg EGCG组和100 mg/kg EGCG组。除对照组外,其余4组通过腹腔注射链脲佐菌素(STZ)构建糖尿病模型。STZ注射72 h后,对各剂量EGCG组大鼠灌胃相应浓度的EGCG,其余两组大鼠灌胃等体积生理盐水。于开始给予EGCG处理后的第4和8周,检测各组大鼠的随机血糖、足底纤维力度和反应时间;于给予EGCG处理第8周,提取大鼠脊髓组织检测p38丝裂原活化蛋白激酶(MAPK)和白细胞介素1β(IL-1β)mRNA相对表达水平。结果(1)在各个时间点糖尿病组和各剂量EGCG组的纤维力度及反应时间均低于对照组(均P<0.05);50 mg/kg EGCG组和100 mg/kg EGCG组各时间点的纤维力度及反应时间均高于糖尿病组及10 mg/kg EGCG组(均P<0.05);而10 mg/kg EGCG组仅第8周的纤维力度及反应时间高于糖尿病组(P<0.05)。(2)糖尿病组和10 mg/kg EGCG组的p38MAPK和IL-1βmRNA相对表达水平均高于对照组(均P<0.05);50 mg/kg EGCG组和100 mg/kg EGCG组的p38MAPK和IL-1βmRNA相对表达水平均低于糖尿病组及10 mg/kg EGCG组(均P<0.05),而糖尿病组与10 mg/kg EGCG组之间差异无统计学意义(P>0.05)。(3)糖尿病组及各剂量EGCG组的随机血糖水平均高于对照组(均P<0.05),但各剂量EGCG组之间及与糖尿病组之间随机血糖值差异均无统计学意义(P>0.05)。结论EGCG可改善糖尿病大鼠的神经病理性疼痛症状,这或与其抑制脊髓组织p38MAPK表达和炎症反应有关。

Caustics study of the effect of glass fibres on dynamic fracture of hardened cement paste

The reflected optical caustics method is applied to study dynamic fracture problems in hardened cement paste. First both the unreinforced cement paste and the glass fibres reinforced cement paste specimens were fabricated and the reflective coating on the surface of the specimen was prepared. Secondly the crack path and the shadow spot patterns during the crack propagation process for the two specimens were recorded by using a multi-spark high speed camera.Thirdly some dynamic parameters of two cement paste specimens including crack onset time the dynamic stress intensity factor and crack growth velocity were determined and analyzed comparatively.This indicates that the glass fibres can improve the fracture resistance and delay fracture time.These results will play an important role in evaluating the dynamic fracture properties of cement paste.

Construction of a Butterfly Web Bridge

A new type of bridge called ＂butterfly web bridge＂ is under construction in Japan. In a butterfly web bridge, the butterfly-shaped web forms a structure that exhibits behavior similar to a double Warren truss. The 80 MPa concrete is used for the butterfly web which has a precast plate with a thickness of 150 mm. As butterfly web is a concrete material, reinforcement provided by prestressing tendons is needed on the tension side. Moreover, the 150 mm plate has no re-bars but is reinforced by steel fibers. This bridge, named Takubogawa Bridge, is a highway bridge and has 10 spans including the 87.5 m maximum span length. Takubogawa Bridge is constructed by flee cantilevering method. The butterfly web enables the construction speed of cantilevering to be advanced about 50% compared with conventional cast-in-situ method and can meet the requirement of light weight and low maintenance.

Haptic Evaluation of the Prickle of Fabrics: Axial Compression Bending Tests On Ramie Fibers

Although smoothness, softness, and stiffness determine the physical and mechanical behavior of a fabric and the subjective assessment of quality when it is handled, the perceived comfort of clothing is more important to consumers. The sensations perceived from the contact of clothing with the skin can greatly influence our over-all state of comfort and one aspect of this is the unpleasant skin sensation of prickle. Surface prickle of fabrics can be a factor limiting the use of the coarser types of ramie in apparel. And the mechanical stimulus of fabric-evoked prickle underlies our discomfort to fabrics independent in the majority of cases of any chemical or the atopic status of the individual. It is known that the prickle of fabric can be reduced by fabric-finishing treatments, but the assessment of fabric prickle is often done subjectively. This is time consuming, and it is difficult to obtain reliable and reproducible results, since variability between subjects in their sensitivity to prickle, such as skin mechanical properties, effective density of nociceptors and the mood state of the individual. In order to find an objective method of measuring the physical properties of the stiff fiber ends protruding from the fabrics to predict prickle, axial compression bending tests were examined by using single ramie fiber. By comparing analysis, it is found that the critical compressing load (Pcr), the bending modulus (E) are the important parameters. The relationship of the critical load (Pcr) with the length of fiber (L) and the fineness of fiber (Nt) has been investigated.

Microstructure and mechanical properties of AZ61 Mg alloy prepared by multi directional forging

AZ61Mg alloy was multi directionally forged(MDFed) during decreasing temperature condition from 643 K to 483 K at a true strain rate of 3×10-3 s-1 up to cumulative strain of∑△ε=4.0 at maximum.A pass strain of△ε=0.8 was employed.While average grain size decreased gradually with increasing cumulative strain,the evolution of fine-grained structure strongly depended on the MDF temperature.Under the condition where the temperature was higher than the most adequate one,grain coarsening partially took place during MDF.In contrast,at lower temperature,inhomogeneous microstructure composed of the initial coarse and newly appeared fine grains was evolved.After straining over∑△ε=3.2(i.e.,over 4 passes of MDF) ,equiaxed ultrafine grains(UFGs) having average size of about and lower than 1μm were uniformly evolved.While the MDFed alloy to∑△ε=4.0 possessed relatively high hardness of HV 99,and it accepted further about 20%cold rolling almost without cracking.Because of the superior formability of the UFGed AZ61Mg alloy,the hardness was further easily raised to HV 120 by following cold rolling.

Performances of super-long span prestressed cable-stayed bridge with CFRP cables and RPC girder

To discuss the applicability of advanced composite carbon fiber reinforced polymer(CFRP) and ultrahigh performance concrete reactive powder concrete(RPC) in super-long span cable-stayed bridges, taking a 1 008 m cable-stayed bridge with steel girders and steel cables as an example,a new cable-stayed bridge in the same span with RPC girders and CFRP cables was designed,in which the cable's cross section was determined by the principle of equivalent cable capacity and the girder's cross section was determined in virtual of its stiffness, shear capacity and local stability. Based on the methods of finite element analysis,the comparative analysis of these two cable-stayed bridge schemes about static performances,dynamic performances,stability and wind resistance behavior were carried out. The results showed that it was feasible to form a highly efficient,durable concrete cable-stayed bridge with RPC girders and CFRP cables and made its applicable span range expand to 1 000 m long around.