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Afield lab-on-a-chip system was constructed to detect mouse immunoglobulin G (mIgG; model protein target) and Escherichia coli (E. coli; model microorganism target) by using light scattering detection of particle immunoagglutination. The antibodies to these targets were conjugated to the submicron particles by covalent binding, and their long-term stability was evaluated. Antibody-conjugated particles were able to be stored in a 4C refrigerator for at least 4 weeks and to be lyophilized as a powder form for the storage in room temperature. The optimum antibody coverage on the particles was 50% for mIgG and 100% for E. coli in terms of assay sensitivity and long-term storage of reagents. Lab-on-a-chip device was fabricated from acrylic plate using an industrial-grade milling machine eliminating the need for photolithography and internal or external pumping. An automatic sampling system was constructed using drip emitters, such that the system can be connected to a pressurized water pipe for detecting E. coli. The automatic sampling system generated the same volume of droplets (70 mL) regardless of pressure. The developed system was successfully tested for E. coli presence in field water samples. The system can potentially be connected to pressurized pipe networks for drinking, processing, irrigation, and wastewater.

Double detection of microsphere light scattering and quantum dot emission was demonstrated for lab-on-a-chip immunoassay without using stationary support. We conjugated quantum dots (QDs) onto microspheres to enable multiplex assays as well as to enhance the limit of detection (LOD). We named this configuration “nano-on-micro” or “NOM”. Upon radiation with UV light (380 nm), a stronger light scattering signal is observed with NOMs than QDs or microspheres alone. Additionally, NOMs are easier to handle than QDs. Since QDs also provide fluorescent emission, we are able to utilize an increase in light scattering for detecting antigen–antibody reaction and a decrease in QD emission to identify which antibody (or antigen) is present. Two types of NOM combinations were used. One batch of microspheres was coated with QDs emitting at 655 nm and mouse IgG (mIgG); the other with QDs emitting at 605 nm and bovine serum albumin (BSA). A mixture of these two NOMs was used to identify either anti-mIgG or anti-BSA. NOM particles and target solutions were mixed in a microfluidic device (using highly carboxylated microspheres as previously demonstrated by our group) and on-chip detectionwas performed using proximity optical fibers. Forward light scattering at 380 nm was collected. With the positive target, the scattering signal was increased. The LOD was as low as 50 ng ml?1 (330 pM) with p < 0.05. Fluorescent emission (655 or 605 nm) was simultaneously collected. With the positive target, the emission signal was attenuated. Therefore, we were able to detect two different antibodies simultaneously with two different detection protocols. We believe this NOM bioassay has the ability to screen for and detect multiple antibodies with minimal sample processing and handling (one-step lab-on-a-chip immunoassay).

Silicon/glass micromachined, fiber optics based, lab-on-chip device and metrological instrumentation for quality evaluation of animal oocytes by VIS/NIR transmission cell-by-cell measurement (400-950 nm) is shown. Several porcine and bovine oocytes were tested. 3 quality classes of porcine and 4 quality classes of bovines oocytes have been identified in a good agreement to classical veterinarian methodology.

Background. There is a lack of data on polymerization of resin-based materials (RBMs) used in paediatric dentistry, using dual-peak light-emitting diode (LED) light-curing units (LCUs). Objective. To evaluate the degree of conversion (DC) of RBMs cured with dual-peak or singlepeak LED LCUs.

对缅甸、越南带有蓝紫色调的天然红宝石样品进行了热处理改善工艺研究,采用激光诱导离解光谱仪(LIBS)和X射线荧光能谱仪(EDXRF)对样品进行定性和定量测试,结果显示,样品中含有Al、Fe、Cr、Ca、Mg、Ti、Si等元素,且随着红宝石紫色调的加深,Fe的质量分数增加,热处理实验中对加热温度,加热时间及速率,添加剂等适当调控,从而得出最佳实验方案;利用USB 4000对处理前、后的样品进行测试分析,结果显示在温度为1 580℃,氧化氛围,添加剂为硼酸钠和三氧化二铝的条件下的热处理工艺,能够很好地改变微量元素Fe,Ti的存在状态,减少由其产生的紫色调,蓝紫色调,使红色纯正。由于样品裂隙发育,即使有助熔剂充填,也并不能很好的改善其透明度,只是在裂隙中残留下白色物质。

我国是水果生产大国,却是水果出口小国。水果商品化处理程度低是导致我国水果国际市场竞争力弱、出口量小的主要原因之一,提高我国的水果商品化处理水平能有效地增强我国水果的国际市场竞争力,扩大我国水果出口量,水果外观和内部品质的快速无损检测是水果商品化处理的重要环节,因而,实现水果外观和内部品质的快速无损检测是非常重要和必要的。

采用USB4000光纤光谱仪,在D65参照光源的条件下,测量各个色级不同荧光强度钻石样品的CIE1931色品坐标和主波长,根据色度学原理计算钻石样品的兴奋纯度和亮度纯度?结果表明,对于不同色级而相同荧光强度的钻石,随着色级的降低,钻石的主波长递减,兴奋纯度和亮度纯度递增,即钻石的颜色饱和度增加;对于同一色级的钻石,随着荧光程度的增加,钻石的主波长递增,兴奋纯度和亮度纯度呈减小趋势,强荧光至弱荧光可使钻石的兴奋纯度和亮度纯度上升1到2个色级,即不同程度的钻石荧光可使钻石颜色提升1~2个色级。

报道了一种蓝光(471nm)抽运的全固态Pr∶KYF激光器,其入射抽运激光阈值功率为0.4W,当注入的抽运功率为2.5W 时,得到了最大212mW 的610nm波长的激光输出。然后采用I类临界相位匹配的β-BaB2O4(BBO)晶体进行内腔倍频,得到了最大11mW 的二次谐波305nm紫外激光输出,通过刀口法可测量到在TEM00模式下,输出光束的质量因子M2=1.25;光-光转换效率达4.4%;输出功率在30min内的不稳定度优于4.3%。采用USB-4000型光谱仪检测到输出为305nm的激光光谱。

为了实现赣南脐橙按内部品质分级,对赣南脐橙可溶性固形物( SSC) 进行快速在线检测研究. 利用USB4000 微型光纤光谱仪在0. 3 m·s - 1的输送速度下在线采集赣南脐橙的半透射光谱( 470 ~ 1 150 nm) ,并采用CARS 变量选择方法对波长变量进行优选,对优选的波长变量应用偏最小二乘( PLS) 回归建立脐橙SSC 在线预测模型,最后利用脐橙SSC 在线预测模型对完全独立的预测集样本进行预测. 研究结果表明: CARS 能有效筛选有用的波长变量,提高预测模型的预测精度;与全光谱PLS 模型相比,CARS-PLS 模型的交互验证相关系数由0. 871 上升为0. 934,交互验证均方根误差( RMSECV) 由0. 560%下降为0. 412%; 独立预测集样本SSC 的预测均方根误差( RMSEP)为0. 649%,SSC 预测残差落在± 1. 0%界限以内的样本占总预测样本数的86. 3%,基本可以满足脐橙SSC 在线检测分级的需要.

实施精细农业需要清晰地了解土壤的空间变异特性以及实时的营养状况,数字农业的发展也对土壤养分的测定迫切地提出了精确的时间和效率上的要求。土壤有机质、全氮、碱解氮、速效磷和速效钾是植物健康成长所必须的营养成分,目前这些指标检测实验室和土肥站一直沿用常规检测方法。这些检测方法需要昂贵的检测设备和对检测人员要求较高,且存在指标检测效率低,检测样品数量小和成本高等问题,是实施精细农业管理的一个重要障碍因素。光谱分析技术作为一种快速、无损、简便的绿色测量方法和分析技术,在土壤养分的测定方面扮演着越来越重要的角色。近红外光谱检测技术具有一系列的优点,如快速、无需样品制备和成本低等优点。近红外光谱能够反映土壤如有机质和全氮等养分信息,使得近红外光谱检测技术在农业与农业环境检测中得到了广泛应用,近红外光谱检测能力主要依靠对C-H, O-H 和N-H功能键的能量吸收进而反映相应土壤养分含量等信息。土壤有机质、氮、磷、钾是农作物生长的主要养分,是土壤养分管理和测土配方施肥的重要对象,随着测土配方施肥技术的大规模推广,迫切需要一种低成本、可靠的土壤养分快速检测方法。

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