科创中国

背景:Notch信号通路在多种人类恶性肿瘤的发生、发展中起关键作用.研究显示Notch与NF-κB信号通路之间的交互作用可促进胰腺癌进展.目的:明确Notch信号通路对胰腺癌侵袭性的影响及其可能机制.方法:体外培养人胰腺癌细胞株BxPC3,以Notch-1 siRNA下调其Notch-1表达,同时设置转染对照siRNA的阴性对照组和不予siRNA干扰的空白对照组.以Transwell细胞侵袭实验观察各组BxPC3细胞的侵袭能力,电泳迁移率变动分析(EMSA)检测NF-κB活性,蛋白质印迹法检测Notch-1、NF-κB p65、血管内皮生长因子(VEGF)、基质金属蛋白酶-9(MMP-9)蛋白表达.结果:经Notch-1 siRNA干扰、Notch-1表达下调的BxPC3细胞,Transwell细胞侵袭实验穿膜细胞数较空白对照组和阴性对照组显著减少(26.5±1.3对78.5±2.4和76.7 ±2.2,P<0.01),NF-κB活性显著降低(P<0.01),NF-κB p65、VEGF、MMP-9蛋白表达显著下调(P<0.05).结论:Notch-1可通过激活NF-κB促进其下游基因VEGF、MMP-9表达,由此增强胰腺癌的侵袭性.

The existing researches on singularity of parallel mechanism are mostly limited to the property and regularity of singularity locus and there is no further research into the geometric relationship between uncontrolled kinematic screw and parallel mechanism in singularity.A 3UPS-S parallel mechanism is presented which fulfils 3-DOF in rotation.The regularity of nutation angle singularity is analyzed based on the Jacobian matrix,and the singularity surface of 3UPS-S parallel mechanisms is obtained.By applying the concept of reciprocal product in screw theory,the singular kinematic screw is derived when 3UPS-S parallel mechanism is in singularity.The geometric relationship between singular kinematic screw and singular configuration of 3UPS-S parallel mechanism is investigated by using programs in MATLAB.It is revealed that there are two kinds of situation.Firstly,the three limbs of 3UPS-S parallel mechanism intersect the singular kinematic screw in space simultaneously;Secondly,two limbs cross the singular kinematic screw while the third limb parallels with that screw.It is concluded that the nutation angle singularity of 3UPS-S parallel mechanism belongs to the singular linear complexes.This paper sheds light into and clarifies the geometric relationship between singular kinematic screw and singular configuration of 3UPS-S parallel mechanism.

In design of flexure mechanism, diminishing the parasitic-motion is a key point to improve the accuracy. However, most of existing topics concentrate on improving the accuracy of linear-motion flexure mechanisms via compensating the parasitic error, but few research the multi-dimensional flexure mechanisms. A general design principle and method for high-precision flexure mechanisms based on the parasitic-motion compensation is presented, and the proposed method can compensate the parasitic rotation in company with translation, or the parasitic translation in company with rotation, or both. The crucial step for the method is that the parasitic motion of a flexure mechanism is formulated and evaluated in terms of its compliance. The overall compliance matrix of a general flexure mechanism is formulated by using screw theory firstly, then the criteria for the parasitic motions is introduced by analyzing the characteristics of the resultant compliance matrix as well as with aid of the concept of instantaneous rotation center. Subsequently, a compliance-based compensation approach for reducing parasitic-motion is addressed as the most important part. The design principles and procedure are further discussed to help with improving the accuracy of flexure mechanisms, and case studies are provided to illustrate this method. Finally, an analytical verification is provided to demonstrate that the symmetry design philosophy widely used in flexure design can effectively improve accuracy in terms of the proposed method. The proposed compensation method can be well used to diminish the parasitic-motion of multi-dimensional flexure mechanisms.

目的 探讨胃肠道间质瘤(GIST)螺旋CT表现与分子生物学特征之间的关系.方法 对54例GIST患者行螺旋CT平扫及三期动态增强扫描.采用免疫组化SP法分别对54例GIST组织中MMP-9及Hpa蛋白表达进行检测免疫组化.结果 MMP-9和Hpa在GIST中的表达在肿块大小(<5 cm和≥5 cm)、肿块边界(清楚和不清楚)、中心有无坏死、有无转移中均有统计学意义(均P < 0.05).MMP-9和Hpa在GIST中的蛋白表达有明显的相关性(r = 0.337,P < 0.05).螺旋CT对胃肠间质瘤的定位准确率为:胃部病变为84.30%,小肠病变为80.20%,直肠病变为100.00%.术前定位准确率为82.40%,术前定性准确率为78.50%.结论 胃肠间质瘤中MMP-9的高表达与Hpa高表达呈一致性,提示二者在胃肠间质瘤的侵袭和转移中可能起协同作用.对肿瘤的形态、定性及远处转移诊断,螺旋CT和病理检查有很好的一致性,说明螺旋CT的诊断结果 准确可信.螺旋CT征象与分子生物学相结合,宏观结合微观,将有可能提高GIST侵袭、转移和预后评估的准确性.

In the prediction of active vibration isolation performance,control force requirements were ignored in previous work.This may limit the realization of theoretically predicted isolation performance if control force of large magnitude cannot be supplied by actuators.The behavior of a feed-forward active isolation system subjected to actuator output constraints is investigated.Distributed parameter models are developed to analyze the system response,and to produce a transfer matrix for the design of an integrated passive-active isolation system.Cost functions comprising a combination of the vibration transmission energy and the sum of the squared control forces are proposed.The example system considered is a rigid body connected to a simply supported plate via two passive-active isolation mounts.Vertical and transverse forces as well as a rotational moment are applied at the rigid body,and resonances excited in elastic mounts and the supporting plate are analyzed.The overall isolation performance is evaluated by numerical simulation.The simulation results are then compared with those obtained using unconstrained control strategies.In addition,the effects of waves in elastic mounts are analyzed.It is shown that the control strategies which rely on unconstrained actuator outputs may give substantial power transmission reductions over a wide frequency range,but also require large control force amplitudes to control excited vibration modes of the system.Expected power transmission reductions for modified control strategies that incorporate constrained actuator outputs are considerably less than typical reductions with unconstrained actuator outputs.In the frequency range in which rigid body modes are present,the control strategies can only achieve 5–10 dB power transmission reduction,when control forces are constrained to be the same order of the magnitude as the primary vertical force.The resonances of the elastic mounts result in a notable increase of power transmission in high frequency range and cannot be attenuated by active control.The investigation provides a guideline for design and evaluation of active vibration isolation systems.

表面抛光可能给K9基片带来额外的杂质和吸收,分离K9基片的表面吸收率与体吸收率有助于改进基片的加工质量和抛光工艺,对抗损伤能力研究具有重要意义.分析了激光量热法测量弱吸收的原理,采用符合ISO 11551要求的激光量热计测量K9基片的弱吸收.对相同工艺抛光的不同厚度K9基片进行了弱吸收表征,实验发现K9基片的弱吸收随着厚度增加近似线性增大.推导了表面吸收率和体吸收率的计算式,实验得出本样品的表面吸收率为1.21×10-5,体吸收率远大于表面吸收率,体吸收系数为1.72×10-3/cm.实验结果显示所用K9样品的吸收主要来自于材料本身,改善抛光工艺对降低其吸收率作用不大.

目的:探讨负向调控miR-9对人鼻咽癌细胞增殖、迁移和侵袭作用。方法:用脂质体Lipofectami-neTM 2000转染合成抑制剂的方法抑制鼻咽癌细胞miR-9表达,转染抑制对照剂作为对照组。 CCK-8法和流式细胞术检测细胞增殖和细胞周期变化;Transwell侵袭实验和划痕实验检测细胞侵袭和迁移能力;免疫印迹实验检测蛋白变化。结果:抑制鼻咽癌细胞miR-9表达后,肿瘤增殖能力降低(P<0.05),G0/G1期细胞增多[CNE2:(57.96±1.39)%vs(47.93±1.76)%,P<0.05;CNE1:(51.24±0.88)% vs(48.29±0.39)%,P<0.05],迁移距离明显缩短[CNE2:(186.50±7.94)μm vs (247.56±15.56)μm,P<0.05;CNE1:(139.06±16.73)μm vs(230.66±14.27)μm, P<0.01],CNE2细胞中侵袭细胞数明显减少(43.00±3.17 vs 65.80±5.20,P<0.01),β-连环蛋白(β-catenin)表达被抑制。结论:在鼻咽癌细胞中,负向调控miR-9可抑制鼻咽癌细胞的增殖、侵袭和迁移。

目的:研究大豆异黄酮( SI)对全脑缺血/再灌注大鼠脑组织线粒体超微结构、细胞凋亡和细胞色素C( Cyt-C)、caspase-3及caspase-9表达的影响,探讨大豆异黄酮对脑缺血/再灌注损伤的作用及机制。方法:60只健康成年SD大鼠随机分为假手术组( sham)、缺血再灌注组( I/R)和大豆异黄酮预处理组( SI)。 SI组给予SI 120 mg· kg-1· d-1连续灌胃21 d,其余2组用等体积生理盐水灌胃,每天1次,第22天I/R组和SI组行手术阻断三血管制备全脑缺血/再灌注模型。缺血1 h,再灌1 h后处死,取大脑皮层,光镜观察脑细胞形态学变化,透射电镜观察线粒体超微结构变化,流式细胞术检测细胞凋亡率,半定量RT-PCR法和免疫组织化学法测定脑组织中Cyt-C、caspase-9及caspase-3的表达。结果: I/R组线粒体膜崩解、嵴消失,脑细胞大量凋亡。与I/R组相比,大豆异黄酮预处理能明显改善线粒体超微结构的损伤,减少脑细胞凋亡率( P<0.01)。 I/R组Cyt-C、caspase-9和caspase-3 mRNA的表达和蛋白的含量高于sham组(P<0.01),与I/R组相比,SI组Cyt-C、caspase-9及caspase-3 mRNA和蛋白的表达显著降低( P<0.01)。结论:大豆异黄酮可能通过稳定线粒体结构,减少线粒体释放Cyt-C,降低caspase-9和caspase-3的表达,抑制细胞凋亡,从而减轻脑缺血/再灌注损伤。

目的:观察脑梗死后Toll样受体9(TLR9)表达量及其在神经元和神经胶质细胞中的表达变化.方法:线栓法制备C57小鼠大脑中动脉闭塞(MCAO)模型,90 min后再灌注.假手术组为对照.再灌注后6h、3d、7d和14 d处死动物(n=3),制备脑冠状位冰冻切片.免疫荧光染色观察TLR9表达量及其在神经元和神经胶质细胞中的表达变化.结果:梗死灶边缘区TLR9的表达量随时间增加,始终高于对侧及假手术组.病变全程偶见神经元胞内小点状TLR9,TLR9阳性率无时间、组间差异.激活态小胶质细胞聚集于梗死灶边缘区,胞内TLR9由散在小点状变为团块状粗颗粒样.TLR9阳性率随时间先升后降,始终高于对侧及假手术组.星形细胞和少突胶质细胞未见TLR9阳性染色.结论:脑梗死后,中枢定居细胞中神经元TLR9维持固有表达,仅小胶质细胞TLR9表达选择性上调,星形细胞及少突胶质细胞无TLR9表达.

针对现有的温湿度测量系统布设线缆复杂的问题,提出了一种基于NRF9E5的无线温湿度监测系统.系统采用DHT21温湿度传感器检测温湿度,以NRF9E5读取温湿度数据并进行无线数据传送.详细介绍了系统硬件结构及硬件电路设计并对系统进行软件测试.经实验测试实现了点到点无线温湿度监测,系统运行稳定,能应用于多种场合的无线温湿度测量.