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不同结构的DNA激活序列对Cas12a反式切割活性的影响
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作者 费心蕊 刘晓玲 刘成辉 《分析测试学报》 CAS CSCD 北大核心 2022年第4期610-617,共8页
CRISPR-Cas12a系统的反式切割活性在其识别特定的DNA激活序列后被激活,这不仅能实现特定DNA靶标的直接定量分析,同时也为构建针对多种生物标志物的体外传感体系带来了新的思路。然而,已有文献中所采用的双链DNA(dsDNA)和单链DNA(ssDNA)... CRISPR-Cas12a系统的反式切割活性在其识别特定的DNA激活序列后被激活,这不仅能实现特定DNA靶标的直接定量分析,同时也为构建针对多种生物标志物的体外传感体系带来了新的思路。然而,已有文献中所采用的双链DNA(dsDNA)和单链DNA(ssDNA)激活序列结构多种多样,缺乏全面、系统的设计指导原则。针对该问题,该文系统研究了不同结构的DNA激活序列对LbaCas12a反式切割活性的影响。通过对比研究,得出以下结论:(1)前间区序列邻近基序(PAM)位点有助于LbaCas12a更高效地靶向结合dsDNA激活序列和ssDNA激活序列;(2)PAM近端区域缺少序列片段会降低Cas12a-crRNA定位激活序列的效率;(3)删除PAM远端序列片段有利于增强LbaCas12a的反式切割活性;(4)由于省略了dsDNA解链过程,ssDNA激活序列在激活LbaCas12a的反式切割活性方面普遍比dsDNA激活序列产生的效果更好。根据这些发现,该文提出了一种LbaCas12a所青睐的高效激活序列结构,其激活的LbaCas2a反式酶切活性较采用含PAM位点的标准dsDNA激活序列高出3.7倍。研究结果为构建基于CRISPR-Cas12a的高效体外生物传感系统提供了重要支撑。 展开更多
关键词 Cas12a 前间区序列邻近基序(PAM) 双链DNA激活序列 单链DNA激活序列 体外传感
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Design of a Weak Signal Detecting Circuit in the Infrared Spectrum Absorbed Type Gas Sensor 被引量:1
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作者 李小平 周佩丽 《Journal of Measurement Science and Instrumentation》 CAS 2011年第4期384-386,共3页
In the infrared spectrum absorbed type gas concentration sensor,voltage signal obtained from the two-channel thermopile infrared detector TPS2534 is very weak.In order to solve this problem,the authors have establishe... In the infrared spectrum absorbed type gas concentration sensor,voltage signal obtained from the two-channel thermopile infrared detector TPS2534 is very weak.In order to solve this problem,the authors have established the structure of the sensor and designed weak signal detecting circuit of the sensor based on infrared spectrum absorption principle,differential de-noising principle and weak signal detecting principle.The authors have made experiments using CH4 gas.The results show that the circuit can remove noise effectively and detect weak electrical signal obtained from the detector. 展开更多
关键词 IR spectrum absorption differential detection weak signal
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Mid-infrared carbon monoxide detection system using differential absorption spectroscopy technique 被引量:4
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作者 董明 隋越 +3 位作者 李国林 郑传涛 陈玫玫 王一丁 《Optoelectronics Letters》 EI 2015年第6期469-472,共4页
A differential carbon monoxide(CO) concentration sensing device using a self-fabricated spherical mirror(e.g.light-collector) and a multi-pass gas-chamber is presented in this paper.Single-source dual-channel detectio... A differential carbon monoxide(CO) concentration sensing device using a self-fabricated spherical mirror(e.g.light-collector) and a multi-pass gas-chamber is presented in this paper.Single-source dual-channel detection method is adopted to suppress the interferences from light source,optical path and environmental changes.Detection principle of the device is described,and both the optical part and the electrical part are developed.Experiments are carried out to evaluate the sensing performance on CO concentration.The results indicate that at 1.013×10~5 Pa and 298 K,the limit of detection(LoD) is about 11.5 mg/m^3 with an absorption length of 40 cm.As the gas concentration gets larger than115 mg/m^3(1.013×10~5 Pa,298 K),the relative detection error falls into the range of-1.7%—+1.9%.Based on 12 h long-term measurement on the 115 mg/m^3 and 1 150 mg/m^3 CO samples,the maximum detection errors are about0.9%and 5.5%,respectively.Due to the low cost and competitive characteristics,the proposed device shows potential applications in CO detection in the circumstances of coal-mine production and environmental protection. 展开更多
关键词 检测系统 差分吸收 一氧化碳 光谱技术 中红外 浓度 装置 球面反射镜
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CO and CO_2 dual-gas detection based on mid-infrared wideband absorption spectroscopy 被引量:2
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作者 董明 钟国强 +2 位作者 苗澍茁 郑传涛 王一丁 《Optoelectronics Letters》 EI 2018年第2期119-123,共5页
A dual-gas sensor system is developed for CO and CO_2 detection using a single broadband light source, pyroelectric detectors and time-division multiplexing(TDM) technique. A stepper motor based rotating system and a ... A dual-gas sensor system is developed for CO and CO_2 detection using a single broadband light source, pyroelectric detectors and time-division multiplexing(TDM) technique. A stepper motor based rotating system and a single-reflection spherical optical mirror are designed and adopted for realizing and enhancing dual-gas detection. Detailed measurements under static detection mode(without rotation) and dynamic mode(with rotation) are performed to study the performance of the sensor system for the two gas samples. The detection period is 7.9 s in one round of detection by scanning the two detectors. Based on an Allan deviation analysis, the 1σ detection limits under static operation are 3.0 parts per million(ppm) in volume and 2.6 ppm for CO and CO_2, respectively, and those under dynamic operation are 9.4 ppm and 10.8 ppm for CO and CO_2, respectively. The reported sensor has potential applications in various fields requiring CO and CO_2 detection such as in the coal mine. 展开更多
关键词 CO and CO_2 dual-gas detection based on mid-infrared wideband absorption spectroscopy
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