Under microwave irradiation,2,2＇-alkoxy-bridging or 4,4＇-alkoxy-bridging dibenzaldehydes reacted with 4-hydroxycoumarin in DMF to give a series of 3,3＇,3″,3＇″-o-and 3,3＇,3″,3＇″-p-phenylenedimethylidinetetrak...Under microwave irradiation,2,2＇-alkoxy-bridging or 4,4＇-alkoxy-bridging dibenzaldehydes reacted with 4-hydroxycoumarin in DMF to give a series of 3,3＇,3″,3＇″-o-and 3,3＇,3″,3＇″-p-phenylenedimethylidinetetrakis-（4-hydroxy-2H-1-benzopyran-2-ones） in moderate yields.The structures of the synthetic coumarin derivatives were characterized with IR,1H NMR and MS spectroscopy as well as X-ray single crystallography.展开更多
Starting with introduction of basic concept of optical coherence tomography(OCT) techniques,this paper focuses on a detailed review of ophthalmic OCT instruments and their clinical applications. As one of the most imp...Starting with introduction of basic concept of optical coherence tomography(OCT) techniques,this paper focuses on a detailed review of ophthalmic OCT instruments and their clinical applications. As one of the most important inventions of ophthalmology instruments,OCT has become a standard imaging tool for daily ophthalmic diagnosis. The imaging capability has been significantly improved during the past ~ 30 years. In this article,several representing systems which have made significant contributions to OCT developments will be reviewed in details. For each system,the system configuration will be discussed first,follow ed by a brief introduction of their clinical applications. The review concludes with discussions on potential directions of OCT developments and expectations for further improvements of OCT imaging capabilities.展开更多
目的筛选针对婴幼儿配方乳粉、发酵乳以及环境样品中沙门氏菌污染最灵敏的检测方法。方法对20种血清型沙门氏菌进行平行检测,对比美国食品与药品管理局/微生物分析手册(Food and Drug Adminis tration/B acteriological Analytical Manu...目的筛选针对婴幼儿配方乳粉、发酵乳以及环境样品中沙门氏菌污染最灵敏的检测方法。方法对20种血清型沙门氏菌进行平行检测,对比美国食品与药品管理局/微生物分析手册(Food and Drug Adminis tration/B acteriological Analytical Manual,FDA/BAM)Chapter 5:Salmonella、ISO 6579—2017 Microbiology of the food chain-Horizontal method for the detection,enumeration and serotyping of和GB 4789.4—2016《食品安全国家标准食品微生物学检验沙门氏菌检验》沙门氏菌检验方法的检出限、灵敏度,使用不同基质(婴幼儿配方奶粉、发酵乳和环境样品)人工染菌样品对3个标准方法的样品适用性进行比较与评价。结果FDA/BAM、ISO 6579—2017、GB 4789.4—2016方法的检出限为10^(-1)~10^(0)CFU/样品。3个标准方法在10^(1)CFU/样品染菌水平灵敏度均为100%;100 CFU/样品染菌水平,灵敏度为95%、90%、90%;10^(-1)CFU/样品染菌水平,灵敏度为65%、50%、45%。对于3类人工污染沙门氏菌的样品,FDA/BAM方法的检出率显著高于ISO6579—2017和GB 4789—2016方法(P<0.05),ISO 6579—2017和GB 4789.4—2016方法检出率无显著性差异(P>0.05)。结论3种方法检出限一致,均可以有效检测食品中沙门氏菌,污染水平为10^(-1)~10^(0)CFU/样品时,FDA/BAM方法的灵敏度较高。在不同人工污染沙门氏菌食品基质中,FDA/BAM方法的检出率显著高于ISO6579—2017和GB 4789—2016。展开更多
基金Supported by the National Natural Science Foundation of China(No.20672091)
文摘Under microwave irradiation,2,2＇-alkoxy-bridging or 4,4＇-alkoxy-bridging dibenzaldehydes reacted with 4-hydroxycoumarin in DMF to give a series of 3,3＇,3″,3＇″-o-and 3,3＇,3″,3＇″-p-phenylenedimethylidinetetrakis-（4-hydroxy-2H-1-benzopyran-2-ones） in moderate yields.The structures of the synthetic coumarin derivatives were characterized with IR,1H NMR and MS spectroscopy as well as X-ray single crystallography.
文摘Starting with introduction of basic concept of optical coherence tomography(OCT) techniques,this paper focuses on a detailed review of ophthalmic OCT instruments and their clinical applications. As one of the most important inventions of ophthalmology instruments,OCT has become a standard imaging tool for daily ophthalmic diagnosis. The imaging capability has been significantly improved during the past ~ 30 years. In this article,several representing systems which have made significant contributions to OCT developments will be reviewed in details. For each system,the system configuration will be discussed first,follow ed by a brief introduction of their clinical applications. The review concludes with discussions on potential directions of OCT developments and expectations for further improvements of OCT imaging capabilities.
文摘目的筛选针对婴幼儿配方乳粉、发酵乳以及环境样品中沙门氏菌污染最灵敏的检测方法。方法对20种血清型沙门氏菌进行平行检测,对比美国食品与药品管理局/微生物分析手册(Food and Drug Adminis tration/B acteriological Analytical Manual,FDA/BAM)Chapter 5:Salmonella、ISO 6579—2017 Microbiology of the food chain-Horizontal method for the detection,enumeration and serotyping of和GB 4789.4—2016《食品安全国家标准食品微生物学检验沙门氏菌检验》沙门氏菌检验方法的检出限、灵敏度,使用不同基质(婴幼儿配方奶粉、发酵乳和环境样品)人工染菌样品对3个标准方法的样品适用性进行比较与评价。结果FDA/BAM、ISO 6579—2017、GB 4789.4—2016方法的检出限为10^(-1)~10^(0)CFU/样品。3个标准方法在10^(1)CFU/样品染菌水平灵敏度均为100%;100 CFU/样品染菌水平,灵敏度为95%、90%、90%;10^(-1)CFU/样品染菌水平,灵敏度为65%、50%、45%。对于3类人工污染沙门氏菌的样品,FDA/BAM方法的检出率显著高于ISO6579—2017和GB 4789—2016方法(P<0.05),ISO 6579—2017和GB 4789.4—2016方法检出率无显著性差异(P>0.05)。结论3种方法检出限一致,均可以有效检测食品中沙门氏菌,污染水平为10^(-1)~10^(0)CFU/样品时,FDA/BAM方法的灵敏度较高。在不同人工污染沙门氏菌食品基质中,FDA/BAM方法的检出率显著高于ISO6579—2017和GB 4789—2016。
