为实现肠炎沙门菌的快速定量分析,采用Tris辅助柠檬酸钠还原法制备新型胶体金并利用Au-S配位作用在纳米金球表面修饰一层4-巯基苯甲酸(4-MBA)拉曼信号分子,然后以此为标记材料建立肠炎沙门菌表面增强拉曼(surface-enhancement of Raman ...为实现肠炎沙门菌的快速定量分析,采用Tris辅助柠檬酸钠还原法制备新型胶体金并利用Au-S配位作用在纳米金球表面修饰一层4-巯基苯甲酸(4-MBA)拉曼信号分子,然后以此为标记材料建立肠炎沙门菌表面增强拉曼(surface-enhancement of Raman scattering,SERS)免疫层析检测技术,并对其灵敏度、特异性和重复性进行考察。结果表明:建立的SERS免疫层析技术对肠炎沙门菌的可视化最低检测限(LOD)为10^(6) CFU/mL,而通过拉曼信号检测时LOD为10^(5) CFU/mL,灵敏度比裸眼观察提高了10倍。在10^(5)~10^(8) CFU/mL的浓度范围可根据标准曲线y=30.23×exp(-x/-147)-215.83(R^(2)=0.995)对肠炎沙门菌进行定量分析。该SERS免疫层析技术与鼠伤寒沙门菌、鸡白痢沙门菌、甲型副伤寒沙门菌等多种血清型沙门菌和大肠杆菌、副溶血弧菌等常见病原无交叉反应,特异性良好。同一批次的不同试纸条和不同批次的试纸条对相同样品的检测结果基本一致,重复性良好。以粪便和鸡蛋壳为基质的加标试验回收率在94.7%~104.9%之间,回收率良好。结果表明,基于金纳米颗粒的肠炎沙门菌SERS免疫层析快速检测技术灵敏度较高,特异性强,重复性好,能弥补传统胶体金试纸条无法定量的不足,可用于肠炎沙门菌的快速定量检测。展开更多
Based on the TRMM dataset, this paper compares the applicability of the improved MCE(minimum circumscribed ellipse), MBR(minimum bounding rectangle), and DIA(direct indexing area) methods for rain cell fitting. These ...Based on the TRMM dataset, this paper compares the applicability of the improved MCE(minimum circumscribed ellipse), MBR(minimum bounding rectangle), and DIA(direct indexing area) methods for rain cell fitting. These three methods can reflect the geometric characteristics of clouds and apply geometric parameters to estimate the real dimensions of rain cells. The MCE method shows a major advantage in identifying the circumference of rain cells. The circumference of rain cells identified by MCE in most samples is smaller than that identified by DIA and MBR, and more similar to the observed rain cells. The area of rain cells identified by MBR is relatively robust. For rain cells composed of many pixels(N> 20), the overall performance is better than that of MCE, but the contribution of MBR to the best identification results,which have the shortest circumference and the smallest area, is less than that of MCE. The DIA method is best suited to small rain cells with a circumference of less than 100 km and an area of less than 120 km^(2), but the overall performance is mediocre. The MCE method tends to achieve the highest success at any angle, whereas there are fewer “best identification”results from DIA or MBR and more of the worst ones in the along-track direction and cross-track direction. Through this comprehensive comparison, we conclude that MCE can obtain the best fitting results with the shortest circumference and the smallest area on behalf of the high filling effect for all sizes of rain cells.展开更多
The surface-enhanced Raman scattering(SERS) optical fiber probes were successfully prepared by self-assembling on polyelectrolyte multilayers. Gold nanorods(Au NRs) were used as SERS enhancement material to give excel...The surface-enhanced Raman scattering(SERS) optical fiber probes were successfully prepared by self-assembling on polyelectrolyte multilayers. Gold nanorods(Au NRs) were used as SERS enhancement material to give excellent biological affinity and stability to the SERS optical fiber probes. Au NRs were synthesized by seed growth method. The synergistic effect between AgNO_(3) and surfactant was investigated, and the highest yield was found when AgNO_(3) was 500 uL. Meanwhile, different SERS optical fiber probes were obtained by selecting silane coupling agent, polyelectrolyte multilayer and graphene oxide(GO) to treat quartz fiber. It was found that the SERS optical fiber probes obtained by the self-assembled on polyelectrolyte multilayers method performed better than those by other methods. In addition, Mapping was combined with finite element simulation to analyze the electromagnetic field distribution at the fiber end face.The electromagnetic field distribution of Au NRs was investigated, the difference of electromagnetic field intensity around the Au NRs with different arrangements was compared, the strongest signal was obtained when the Au NRs were head-to-head. Finally, sensitivity of the optimized SERS optical fiber probes could reach 10^(-9)mol/L, with excellent stability and repeatability.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. U20A2097,42075087, 91837310)the National Key Research and Development Program of China (Grant No. 2021YFC3000902)。
文摘Based on the TRMM dataset, this paper compares the applicability of the improved MCE(minimum circumscribed ellipse), MBR(minimum bounding rectangle), and DIA(direct indexing area) methods for rain cell fitting. These three methods can reflect the geometric characteristics of clouds and apply geometric parameters to estimate the real dimensions of rain cells. The MCE method shows a major advantage in identifying the circumference of rain cells. The circumference of rain cells identified by MCE in most samples is smaller than that identified by DIA and MBR, and more similar to the observed rain cells. The area of rain cells identified by MBR is relatively robust. For rain cells composed of many pixels(N> 20), the overall performance is better than that of MCE, but the contribution of MBR to the best identification results,which have the shortest circumference and the smallest area, is less than that of MCE. The DIA method is best suited to small rain cells with a circumference of less than 100 km and an area of less than 120 km^(2), but the overall performance is mediocre. The MCE method tends to achieve the highest success at any angle, whereas there are fewer “best identification”results from DIA or MBR and more of the worst ones in the along-track direction and cross-track direction. Through this comprehensive comparison, we conclude that MCE can obtain the best fitting results with the shortest circumference and the smallest area on behalf of the high filling effect for all sizes of rain cells.
基金Funded by National Natural Science Foundation of China (Nos.51372179, 51772224)the Open Projects Foundation of Yangtze Optical Fiber and Cable Joint Stock Limited Company (YOFC)(No.SKLD1705)。
文摘The surface-enhanced Raman scattering(SERS) optical fiber probes were successfully prepared by self-assembling on polyelectrolyte multilayers. Gold nanorods(Au NRs) were used as SERS enhancement material to give excellent biological affinity and stability to the SERS optical fiber probes. Au NRs were synthesized by seed growth method. The synergistic effect between AgNO_(3) and surfactant was investigated, and the highest yield was found when AgNO_(3) was 500 uL. Meanwhile, different SERS optical fiber probes were obtained by selecting silane coupling agent, polyelectrolyte multilayer and graphene oxide(GO) to treat quartz fiber. It was found that the SERS optical fiber probes obtained by the self-assembled on polyelectrolyte multilayers method performed better than those by other methods. In addition, Mapping was combined with finite element simulation to analyze the electromagnetic field distribution at the fiber end face.The electromagnetic field distribution of Au NRs was investigated, the difference of electromagnetic field intensity around the Au NRs with different arrangements was compared, the strongest signal was obtained when the Au NRs were head-to-head. Finally, sensitivity of the optimized SERS optical fiber probes could reach 10^(-9)mol/L, with excellent stability and repeatability.
