A Label-Free Multisensing Immunosensor Based on Imaging Ellipsometry

An immunosensor based on imaging ellipsometry and its potential applications was demonstrated in this paper. It has been proven a fast, reliable, and convenient method to quantify the thickness distribution of protein layers or detect protein concentration in solution. Combined with a protein chip, the immunosensor was able to detect multiple analytes simultaneously without any labeling. Preliminary results demonstrated how this immunosensor could be used to monitor several independent biospecific binding processes in real-time and in situ conditions.

The damage evaluation of rigid particle filled polymer

In this paper, the rigid particle filled polymer is studied in the hope to understand the real damage mechanisms. Two damage parameters were introduced and measured. One is the macro-damage of the materials calculated from the modulus measured, another is micro-damage describing the interfacial debonding or the percentage of the particle debonded from the matrix. The damage rate of the macro damage decreases, while the micro damage increases with the applied stress.

Beam splitting of low-contrast binary gratings under second Bragg angle incidence

Beam splitting of low-contrast rectangular gratings under second Bragg angle incidence is studied. The grating period is between lambda and 2 lambda. The diffraction behaviors of the three transmitted propagating orders are illustrated by analyzing the first three propagating grating modes. From a simplified modal approach, the design conditions of gratings as a high-efficiency element with most of its energy concentrated in the -2nd transmitted order (similar to 90%) and of gratings as a 1 x 2 beam splitter with a total efficiency over 90% are derived. The grating parameters for achieving exactly the splitting pattern by use of rigorous coupled-wave analysis verified the design method. A 1 x 3 beam splitter is also demonstrated. Moreover, the polarization-dependent diffraction behaviors are investigated, which suggest the possibility of designing polarization-selective elements under such a configuration. The proposed concept of using the second Bragg angle should be helpful for developing new grating-based devices. (C) 2008 Optical Society of America.

Investigation of the spectroscopic properties of Yb3+-doped yttrium lanthanum oxide transparent ceramic

Spectroscopic properties of (Y0.9-xLa0.1Ybx)(2)O-3 transparent ceramic were studied. Two main absorption peaks of the specimen are centered at 940 and 970 nm, which are suitable for InGaAs laser diode pumping. The main emission peaks were located at 1032 and 1075 nm with larger emission cross-section and longer fluorescence lifetime than those of Yb:Y2O3. These properties of (Y0.9-xLa0.1Ybx)(2)O-3 transparent ceramic are favorable to achieve high efficiency and high power laser output. (c) 2007 Elsevier B.V. All rights reserved.

木本植物对大气污染指示与监测作用研究

本文研究了木本植物的不同部位即叶片、枝条和树皮以及植物的生理指标如气孔阻力对大气S02、TSP和重金属污染的指示和监测作用，并用树木年轮指示大气污染的历史和程度。结果认为： 承德市大气污染自1703年城市化以来开始出现，但达到严重污染水平则出现在本世纪50年代以来尤其是最近10-20年城市化与工业化的加剧，主要污染物以S02为主，从避暑山庄修建前的<0.1μg m-3达到目前的30μg m-3，重金属污染Fe自1927-45大庙铁矿开采后出现，Mn、Ni、Pb等出现在工业化以来的最近40-50年中，上述污染物含量在木质部年轮中明显升高，如S增加了10倍以上，Pb增加了560% (P<0.00l)。 不同城市功能区树皮pH和气孔阻力不同，主要与大气中的S02和TSP有关，据此可监测大气S02和TSP污染。前者以榆树、加拿大杨、垂柳和国槐最佳，相关系数分别可达-0.8384 (P<0.0l)，-0.7447、-0.6904和-0.6552 (P<0.05);后者则以白腊和旱柳下表皮最好，相关系数达0.9968和0.9951 (P<0.00l)。在扫描电镜下发现气孔受大气TSP影响出现不同程度的堵塞现象，主要有2种途径，小型颗粒物(<5μm)进入气孔腔，大型颗粒物(>30μm)可将气孔封盖。 植物不同器官部位污染物含量以树皮为最高，其次是枝条或叶，因而适宜的指示或监测部位是叶或枝条。主分量分析认为：承德市大气污染物以S为主，重金属Fe、Zn、Mn也有一定的贡献，Pb仅出现在繁忙道路区。不同季节污染物含量变化以休眠期最高，生长初期次之，生长旺盛期最低，如S和Pb分别从0.75 mg g-1和0.7 mg g-1上升到1.5 mg g-1和2.0 mg g-1(P<0.001)。植物不同季节污染物含量的变化反应了大气污染物季节变化特点，因而可以指示或监测大气污染尤其是S02污染。其中刺槐多部位复相关模型监测效果最佳，复相关系数可达0.987;某些植物单一部位的监测作用也较好，叶以珍珠梅最佳，相关系数为0.8695 (P<0.001)，枝以油松、珍珠梅、垂柳为好(r≥0.8，P <0.001)，树皮以刺槐为佳，r=0.8615 (P<0.0l)。植物不同部位的污染物含量还可用来评价大气环境质量，其中复合污染指数可以 评价总的大气环境质量，S污染指数和重金属污染指数可以评价S02、重金属和TSP污染，与直接利用污染物浓度法基本一致。油松不同部位对于大气S02的指示作用可表现为年轮对大气污染历史的指示或监测，针叶对现状S02污染的预测，并利用针叶对于S02的监测结果，绘制了大气S02污染分布图。 总之，本文利用古松年轮和现状城市植物的枝条、叶和树皮中的污染物含量以及树皮酸度等不同方面的指标，对承德市大气污染的历史和现状进行了指示与监测，即承德市大气污染从过去到现在均以S02为主，植物不同部位可以非常有效地进行大气S02污染的监测与评价，其中多部位的复相关模型预测效果极佳。另外，由植物监测而绘制的大气S02分布图，较准确地揭示了承德市大气S02现状分布规律。

Enhanced apoptotic action of trichosanthin in HIV-1 infected cells

Trichosanthin (TCS) is a type 1 ribosome-inactivating protein (RIP) effective against HIV-1 replication. The mechanism is not clear. Present results suggested that the antiviral action tray be partly mediated through enhanced apoptosis on infected cells. TCS induced apoptosis in normal H9 cells and this action was more potent in those infected with HIV-1. In flow cytometry study, TCS induced larger population of apoptotic H9 cells chronically infected with HIV-1 in a dose-dependent manner. At TCS concentration of 25 mu g/ml. 8.4% of normal H9 cells were found to be apoptotic whereas the same concentration induced 24.5% in HIV-1 chronically infected cells. Such difference was not found in the control experiments without TCS treatment. Two other studies supported this action. Cytotoxic study showed that cell viability was always lower in HIV-1 infected cells after TCS treatment, and DNA fragmentation studs confirmed more laddering in infected cells. The mechanism of TCS induced apoptosis in normal or infected H9 cells is not clear. Results in this study demonstrated that TCS is snore effective in inducing apoptosis in HIV-1 infected cells. This may explain in part the antiviral action of TCS. (c) 2005 Elsevier Inc. All rights reserved.

γ-氨基丁酸受体和甘氨酸受体在大鼠丙泊酚麻醉中的作用

目的 研究丙泊酚对大鼠海马CA1区电刺激诱发兴奋性突触后电流(EPSC)的影响,分析γ-氨基丁酸(GABA)受体和甘氨酸受体在丙泊酚麻醉中的作用.方法 断头法分离wistar大鼠(13～19 d)海马半脑,切出400 μm厚度的海马脑片,全细胞膜片钳技术记录CA1区锥体神经元EPSC.80张脑片分为八组:脂肪乳剂组,50 μmol/L丙泊酚组,100 μmol/L丙泊酚组,200 μmol/L丙泊酚组,SR95531组,士的宁组,SR95531+100 μmol/L丙泊酚组,士的宁+100 μmol/L丙泊酚组,每组10张.SR95531+100 μmol/L丙泊酚组和士的宁+100 μmol/L丙泊酚组先在循环液中加入10 μmol/L SR95531或4 μmol/L士的宁预孵脑片30 min.八组均记录基础EPSC 10 min,然后加入不同药物,继续记录EPSC 40 min.膜钳制电压为-70 mV.结果 脂肪乳剂、SR95531和士的宁对EP-SC幅值无影响;丙泊酚呈剂量依赖性的抑制EPSC幅值,50、100、200 μmol/L丙泊酚最大抑制EPSC幅值为14.4%、52.3%、67.8%;SR95531+100 μmol/L丙泊酚组加入丙泊酚后,EPSC幅值基本无改变;士的宁+100 μmol/L丙泊酚组加入丙泊酚后,EPSC幅值仍然下降,最大抑制程度为34.7%.结论 丙泊酚主要通过增强GABAA受体功能使兴奋性突触活动降低,甘氨酸受体在其中起到协同和调节作用.

Thermal quenching of luminescence from buried and surface InGaAs self-assembled quantum dots with high sheet density

Variable-temperature photoluminescence (PL) spectra of Si-doped self-assembled InGaAs quantum dots (QDs) with and without GaAs cap layers were measured. Narrow and strong emission peak at 1075 nm and broad and weak peak at 1310 nm were observed for the buried and surface QDs at low temperature, respectively. As large as 210 meV redshift of the PL peak of the surface QDs with respect to that of the buried QDs is mainly due to the change of the strain around QDs before and after growth of the GaAs cap layer. Using the developed localized-state luminescence model, we quantitatively calculate the temperature dependence of PL peaks and integrated intensities of the two samples. The results reveal that there exists a large difference in microscopic mechanisms of PL thermal quenching between two samples. (c) 2005 American Institute of Physics.

Mode-coupling analysis of three-dimensional microdisk resonators by the finite-difference time-domain technique

Quality factor enhancement due to mode coupling is observed in a three-dimensional microdisk resonator. The microdisk, which is vertically sandwiched between air and a substrate, with a radius of 1 mu m, a thickness of 0.2 mu m, and a refractive index of 3.4, is considered in a finite-difference time-domain (FDTD) numerical simulation. The mode quality factor of the fundamental mode HE71 decreases with an increase of the refractive index of the substrate, n(sub), from 2.0 to 3.17. However, the mode quality factor of the first-order mode HE72 reaches a peak value at n(sub) = 2.7 because of the mode coupling between the fundamental and the first-order modes. The variation of mode field distributions due to the mode coupling is also observed. This mechanism may be used to realize high-quality-factor modes in microdisks with high-refractive-index substrates. (c) 2006 Optical Society of America.

一种模拟驱动的Web应用程序性能测试方法

性能是Web应用程序成功的要素之一 ,性能测试则是保证这一要素的重要手段 但由于Internet及Web用户的不确定性 ,Web应用程序的性能测试难于传统Client/Server的测试 比较了 3种主要的Web性能测试方法 ;提出了一种简单可行的、通用的方法———模拟驱动的自动负载测试方法 关键的步骤有 :根据系统使用方式和客户端各种特征的分布信息来确定测试负载、设计测试用例 ;利用测试工具开发相应的测试脚本 ;运行测试用例模拟不同类型用户的典型行为 ;收集被测程序的性能数据 结合实例详述了该方法 ,并给出了测试计划的模板

重力式热管工作温度的计算

气—气型重力式热管换热器用于热回收时，首先要根据给定的温度范围选择热管。关于热管工质的允许工作温度范围，许多热管文献都有介绍(1～3)。但是工作状态下热管管内工质温度如何计算:对于给定的冷、热流体温度，如何根据热管工质的许用温度调节冷热端热阻;或者如何根据已知的冷热流