可调式外径千分尺组合研磨器的研制与应用

外径千分尺的多规格性使其测量面磨损后的修研需要配置不同规格尺寸的系列研磨器。为了减少研磨器数量,提高研磨效率,降低修理难度,研制了一种可调式千分尺组合研磨器。介绍了组合研磨器的结构和工作原理、制造和装配方法,并对其进行了精度分析。     

抑制乳腺癌耐药蛋白基因逆转肝癌多药耐药的体内实验

目的探讨小片段RNA干扰抑制乳腺癌耐药蛋白(BCRP)基因及其蛋白表达在裸鼠体内逆转人肝癌组织多药耐药(MDR)的可行性。方法建立裸鼠多药耐药肝细胞癌模型,随机分为A组和B组,A组(对照)注射生理盐水40μl+Lipo-fectamine200010μl,B组注射BCRP基因RNAi质粒pSUPER-BCRP40μl+Lipofectamine200010μl,两组均行瘤内注射1次。5d后,各组均经腹腔注射阿霉素5mg/kg化疗,每5d给药1次,共4次。彩色B超测量肿瘤体积;化疗结束后1周处死裸鼠,RT-PCR及Westernblot法检测各组裸鼠肿瘤组织中BCRP基因mRNA的转录水平及其蛋白的表达水平。结果B组每次化疗后肿瘤体积均明显缩小;除第1次化疗外,其余各次化疗后肿瘤体积均小于A组;化疗结束后,B组与A组相比,肿瘤组织中BCRP基因mRNA的转录水平和BCRP蛋白的表达水平均明显降低。结论BCRP基因RNAi质粒pSUPER-BCRP可有效降低裸鼠肝癌组织BCRP基因mRNA的转录水平及其蛋白的表达水平,在一定程度上逆转MDR,为从基因水平逆转MDR提供了初步的实验依据。     

关于F．Smarandache因子分拆问题

对于F.Smarandache因子分拆,利用初等及组合方法研究一些特殊整数的所有不同分拆个数的计算问题,并给出一个确切的计算公式,从而解决了Amarnath Murthy及Charles Ash-bacher提出的2个猜想!     

Constrained Nanoparticles Deliver siRNA and sgRNA to T Cells In Vivo without Targeting Ligands

T cells help regulate immunity, which makes them an important target for RNA therapies. While nanoparticles carrying RNA have been directed to T cells in vivo using protein‐ and aptamer‐based targeting ligands, systemic delivery to T cells without targeting ligands remains challenging. Given that T cells endocytose lipoprotein particles and enveloped viruses, two natural systems with structures that can be similar to lipid nanoparticles (LNPs), it is hypothesized that LNPs devoid of targeting ligands can deliver RNA to T cells in vivo. To test this hypothesis, the delivery of siRNA to 9 cell types in vivo by 168 nanoparticles using a novel siGFP‐based barcoding system and bioinformatics is quantified. It is found that nanomaterials containing conformationally constrained lipids form stable LNPs, herein named constrained lipid nanoparticles (cLNPs). cLNPs deliver siRNA and sgRNA to T cells at doses as low as 0.5 mg kg^?1 and, unlike previously reported LNPs, do not preferentially target hepatocytes. Delivery occurs via a chemical composition‐dependent, size‐independent mechanism. These data suggest that the degree to which lipids are constrained alters nanoparticle targeting, and also suggest that natural lipid trafficking pathways can promote T cell delivery, offering an alternative to active targeting approaches.     

基于约束满足方法求解炼钢—连铸生产调度问题

针对各阶段均有并行机的炼钢—连铸生产调度问题,建立了问题的约束满足模型．通过分析炼钢—连铸调度问题特点,将其归结为最小化操作开工时间偏移的调度问题．在求解过程中,首先用变量选择和值选择启发式方法构造时间可行的初始调度,然后应用冲突检查算法检测资源冲突，基于回跳的后向修剪组合算法修复冲突,直至得到一个一致性的最终解．数据实验表明本文提出的方法是有效的.     

基于分布估计算法的组合电路测试生成

基于遗传算法生成的测试矢量集的故障覆盖率要低于确定性方法．本文分析指出造成这种现象的一个可能原因在于，组合电路测试生成过程中存在高阶、长距离模式，从而导致遗传算法容易陷人局部极值或早熟收敛．为此，本文首次提出使用分布估计算法生成测试矢量．该方法使用联合概率分布捕捉电路主输人之间的关联性。从而避免了高阶、长距离模式对算法的影响，缓解了算法早熟收敛问题．针对ISCAS-85国际标准组合电路集的实验结果表明，该方法能够获得较高的故障覆盖率．     

A note on resource allocation scheduling with position-dependent workloads

In this note, single machine scheduling with concurrent resource allocation and position-dependent workloads is studied. The aim is to find jointly the optimal sequence and the optimal resource allocation. A bicriteria analysis of the problem is provided where the first criterion is to minimize the scheduling cost (i.e. makespan, total completion time, total absolute differences in completion times, total absolute differences in waiting times) and the second criterion is to minimize the total resource consumption cost. It is proved that four bicriteria problems can be solved efficiently.     

Enhanced Targeted Delivery of Doxorubicin Based on Acid Induced Charge Reversal and Combinational Stimuli‐Responsive Nanocarrier

To elevate the efficacy and to attenuate the adverse effects remain a tough challenge in exploring anticancer drug delivery systems. A nanocarrier characteristic of acid induced charge reversal and acid/redox/magnetic combinational stimuli‐responsiveness is designed. This system exhibits weaker repulsion between the carrier and the cancer cell membrane, resulting in enhanced uptake. After nanocarriers enter the cell, the system exhibits negative‐to‐positive charge reversal in response to the low intracellular pH value. Moreover, after the uptake, the carrier will be further dissociated by glutathione in cytoplasm via the reduction of the disulfide bond, leading to the rapid release of the encapsulated DOX into the nuclei. In vitro release study expresses the sequent stimulus release profile. The antitumor activity tested in CT26 tumor‐bearing mice reveals efficient therapeutic efficacy and as low adverse effect as PBS. H&E staining and immunohistochemical analysis of tumor tissues as well as pathological test of tissue sections of vital organs confirm the high antitumor activity and low tissue toxicity. Thus, the belief that this system has a good prospect in the field of cancer clinical chemotherapy.

     

求解车辆路径问题的改进遗传算法

车辆路径问题是一个典型的组合优化类问题,遗传算法是求解此类问题的方法之一。针对遗传算法容易出现“早熟”现象的问题,借鉴免疫算法通过抗体浓度抑制以保持种群多样性的优势以及模拟退火算法的个体选择策略,提出了一种改进的遗传算法,并将其用于解决车辆路径问题。实验验证了算法的有效性以及求解的效率和解的质量。