Sodium dichloroacetate improves radiosensitivity of U251 cells

AIM: To study the change of radiosensitivity of U251 cells after treated with sodium dichloroacetate (DCA) and further to explore the possible mechanism.METHODS: The U251 cells were divided into 4 groups: control group, DCA group, X-ray irradiation without DCA pretreatment (IR) group and X-ray irradiation with DCA pretreatment (DIR) group. MTT assay was applied to determine the cell viability. The intracellular reactive oxygen species (ROS) were detected by DHE fluorescence. The expression level of Bcl-2 was assessed by Western blot. The percentage of apoptosis of cells was determined by flow cytometry. RESULTS: No difference between control group and DCA group in cell viability (P>0.05) was observed. However, the cell viability of both IR group and DIR group was markedly reduced compared with control group (P<0.05). Furthermore, the viability of DIR group was significantly decreased compared with IR group (P<0.05). The percentage of ROS positive cells was obviously increased in DIR group compared with IR group (P<0.05). The expression level of Bcl-2 was sharply decreased in DIR group (P<0.05) and the percentage of apoptosis of cells was significantly elevated (P<0.05) in DIR group compared with IR group.CONCLUSION: The better antitumor effect was obtained by improving the radiosensitivity through pretreating the cells with DCA, and the possible mechanism was down-regulation of the Bcl-2 expression by developing the intracellular ROS.     

Roles of atypical chemokine receptors in progression and metastasis of tumor

Chemokines and their receptors have been implicated mostly in tumor progression and metastasis. Atypical chemokine receptors (ACKRs) comprise a group of 7-transmembrane domain proteins structurally similar to G protein-coupled receptors. However, ACKRs do not induce classical signaling via the typical G protein-mediated pathways. ACKRs efficiently internalize the cognate chemokine ligands and act as scavengers instead. ACJRs are composed of at least 3 members of chemokine receptors:Duffy antigen receptor for chemokines (DARC, also known as ACKR1), D6 (also known as ACKR2) and ChemoCentryx chemokine receptor (CCX-CKR, also known as ACKR4). These receptors bind to and/or internalize their chemoattractant ligands without activating signal transduction cascades leading to cell migration. In this review, we summarize the recent progress regarding the roles of ACKRs in the progression and metastasis of tumor.     

有机锰锌的络合强度与其在肉鸡体内吸收利用的关系及机制

1 有机微量元素的概念和分类 1.1 有机微量元素的概念 有机微量元素是指微量元素的无机盐与有机配位体形成产物的总称,如赖氨酸铜、白锰等.有机微量蛋元素产品被研发企业称为所谓的"第三代"微量元素添加剂.有机微量元素营养是动物营养工作者目前研究的热点之一.     

黔北梨园主要病虫害的发生动态和演变原因及防治

通过对黔北梨园主要病虫害的调查研究,分析近些年来该地区梨树病虫种群的发生动态和演变原因,提出加强农业措施,积极开展物理、生物防治,合理使用化学防治的对策。     

我国马铃薯批发市场价格波动性研究

1996 年1 月至2010 年12 月我国马铃薯市场价格波动较为明显,长期来看呈现上升的趋势;马铃薯市场价格具有明显的季节波动性,每年的2～6 月其价格在长期趋势价基础上均有不同程度的上涨,7月至翌年1月则出现不同程度的下滑;1996 年2月至2007年10月,马铃薯批发市场价格已大致历经了2个完整的循环周期,平均周期长度为70.5 个月。     

黄华占市场推广前景分析与建议

优质稻品种黄华占是广东省农业科学院应用现代核心种质育种理念选育的两系籼稻品种。因其特征特性优良,每年在鄂、赣、湘等省推广应用面积超过27万hm2;其系列配套技术也正在完善之中;以此为基础,分析了该品种的市场推广前景;同时,提出了同类品种的推广建议。     

Ratio control strategy for solving system response lag of continuously variable transmission system

Generally, there’s a system response lag in the continuously variable transmission system, and this leads to a deviation of the engine work point from the optimal operation line of the minimum fuel consumption. To reduce the influence of system response lag, a new CVT ratio control strategy with the system response lag parameter during computing target ratio is proposed. Simulation results indicate that the proposed control strategy can overcome the effect of system response lag, so as to keep the engine work point on the optimal operation line effectively. A comparison of fuel consumption is made between the proposed control strategy and the traditional one by simulation, and results indicate that the proposed control strategy reduces the fuel consumption of the system by 2.85％.     

黔东武陵山区不同居群野生半夏种质特性初步评价

对黔东武陵山区7种野生半夏进行引种栽培试验,对其抗病虫性、地下块茎性状、产量等特性进行研究。结果表明:铜仁市所产野生半夏的地下块茎性状及亩产量两个方面表现较好,而对病虫害的抗性稍弱于其它产地半夏。     

Bamboo simulation based on fractal algorithm

Fractal theories are quite popular in modeling and simulation of objects with irregular shapes. The combination of fractal theories and virtual reality technologies may be used to generate the realistic and complex nature objects. Plants simulation is one of the most important fields in computer graphics. The simulation algorithms of Bamboo are discussed. The conventional L-system modeling approach is improved based on the single-axis characteristics of Bamboo, and the relevant method, e.g. the displacement mapping technique used in Bamboo internodes modeling and rendering is discussed as well. Moreover, based on the basic idea of particle system, an improved simulation approach for distribution pattern of Bamboo is presented.This improved simulation algorithm can make the random distribution of particles break the rules of rectangular shape. Simulation results show that the proposed methods can simulate realistic Bamboo forms and distribution patterns in the nature.     

钢琴用云杉木材吸湿性及尺寸稳定性研究

主要针对钢琴用云杉木材进行了吸湿性及尺寸稳定性研究,通过高温热处理及二次干燥两种工艺分别对木材进行了处理,试验结果表明:两种工艺处理方法可以有效降低木材的吸湿性,提高木材的尺寸稳定性,同时,在温度140℃、时间8 h的条件下进行的高温热处理,云杉木材吸湿性最低、尺寸稳定性最好.