提高表面等离子体共振(SPR)阵列检测的灵敏度是蛋白质组学和药物发现与开发的迫切需要。提出了一种基于五步移相时域调制相位干涉成像的变曝光时间图像采集法,通过增大信号幅值来提高光强测量信噪比。在一个相位测量周期的5帧图像中,每...提高表面等离子体共振(SPR)阵列检测的灵敏度是蛋白质组学和药物发现与开发的迫切需要。提出了一种基于五步移相时域调制相位干涉成像的变曝光时间图像采集法,通过增大信号幅值来提高光强测量信噪比。在一个相位测量周期的5帧图像中,每帧图像都采用不同的曝光时间,使得每帧图像的灰度值达到最大,从而提高光强测量的信噪比,保证相位成像检测的高灵敏度。实验结果表明,通过优化电路设计和对CCD致冷控温,自行设计的CCD传感系统的检测灵敏度达到了1.2×10-6RIU(refractive index unit)。在此基础上,采用变曝光时间图像采集法可有效抑制光散粒噪声和CCD读出噪声,将检测灵敏度再提高35%。该方法不仅适用于SPR相位成像检测,而且还可用于其他定步长和等步长相移法以及帧间灰度值变化大的图像采集及相关检测。展开更多
A double-exposure fabrication method without any intensity shadow mask to fabricate arbitrarily apodized fiber Bragg gratings（ FBGs） with narrow bandwidth is demonstrated by controlling the total ultra violet （UV）...A double-exposure fabrication method without any intensity shadow mask to fabricate arbitrarily apodized fiber Bragg gratings（ FBGs） with narrow bandwidth is demonstrated by controlling the total ultra violet （UV） irradiation along the grating by varying the speed of a translation stage. The UV source used is a stable continuous intracavity frequency-doubled argonion laser. The parameters （such as length, apodization profile, average index change）of FBGs can be easily changed with this method. The total UV irradiation is kept constant in the doubleexposure process because of the precise control of the exposure time, which ensures that the apodized FBG＇s bandwidth can be extremely narrow. The full width at half maximum （FWHM） bandwidth of the 2-cm-long apodized FBG fabricated by this method is 0. 15 nm with a maximum reflectivity of more than 95%.展开更多
Heat-shock proteins （HSPs） play an undisputed role for maintaining cellular functioning under environmental challenges and protein denaturing conditions. Compelling evidence points to an evolutionary important role ...Heat-shock proteins （HSPs） play an undisputed role for maintaining cellular functioning under environmental challenges and protein denaturing conditions. Compelling evidence points to an evolutionary important role of HSPs and a strict evolutionary control of these proteins as a balance between benefits and costs. While there is a great potential for using HSP expression for detecting natural adaptation and exposure to stress in natural populations, some obstacles and key issues await investigation. From an ecological perspective these key issues needs to be resolved in order to fully appreciate the complex responses and adaptations to stress and to increase our understanding of HSPs and other molecular chaperones for stress adaptation and potential use as biomarkers. Here, the current knowledge and understanding of HSPs is reviewed and a number of key issues including the interpretation of elevated HSP levels, the complications of extrapolating between laboratory and field conditions, the effects of choice of traits and methodology and the larger intra-and extracellular networks of interactions that HSPs participate in are discussed [Current Zoology 56 （6）： 703-713, 2010].展开更多
A socio-economic data set on China＇s historical flood losses for the period 1984--2012 was compiled to analyze the exposed population, economy, and crop area as well as the vulnerabilities of the population and econo...A socio-economic data set on China＇s historical flood losses for the period 1984--2012 was compiled to analyze the exposed population, economy, and crop area as well as the vulnerabilities of the population and economy to floods. The results revealed that the exposed population was approximately 126 persons km-2 per year when taking China as a whole; in terms of the economy, potential losses due to floods were estimated to be approximately 1.49 million C/W4 km 2 and the crop area exposed to floods covered 153 million hm2 per year. China＇s total exposure to floods significantly increased over the analysis period. The areas that showed the higher exposure were mainly located along the east coast. The population＇s vulnerability to floods showed a significantly increasing trend, however, the economic vulnerability showed a decreasing trend. The populations and economies that were most vulnerable to floods were in Hunan, Anhui, Chongqing, Jiangxi, and Hubei provinces. The municipalities of Shanghai, Beijing, and Tianjin showed the lowest vulnerabilities to floods.展开更多
Kinetics of color change in tomato purees dried using microwave and conventional method were investigated. For this purpose, the color parameters of Hunter L,a,b and browning index （A42o）, and estimated values of ch...Kinetics of color change in tomato purees dried using microwave and conventional method were investigated. For this purpose, the color parameters of Hunter L,a,b and browning index （A42o）, and estimated values of chroma, hue angle, AE, Hunter a/b and a ~ b were examined. The changes in color of tomato samples followed both zero and first order kinetic models to describe visual color changes, and ＆E parameters followed first order kinetic. It was concluded that Hunter axb parameters can be used adequately to follow up the color change of tomato samples during the drying.展开更多
Plant stress caused by exposure to magnetic fields （MF） induces modifications at molecular level, particularly in DNA synthesis, structure, and function. The objective of this study was to determine the effect of va...Plant stress caused by exposure to magnetic fields （MF） induces modifications at molecular level, particularly in DNA synthesis, structure, and function. The objective of this study was to determine the effect of various doses of non-ionizing radiation of magnetic field on date palm （Phoenix dactylifera L.） based on DNA content. Date palm seedlings （cv. Khalas） established for 2 weeks on filter paper were subjected to static magnetic field and alternating magnetic field. Static magnetic fields （SMF） were applied at 10, 50 and 100 mT for 30, 60, 120, 180, 240 and 360 min; while alternating magnetic field applied by magnetic resonance imaging （MRI） at 1500 mT for 1, 5, 10 and 15 min. The seedlings were grown in potting soil following exposure for 4 weeks after which DNA was extracted from leaves and its content was determined. Generally, the exposure to magnetic field caused reduction in the content of DNA. The lowest exposure time tested, 30 rain, was sufficient to induce reduction in DNA content. This was true even at the lowest intensity, 10 mT. This dosage caused the DNA content to decrease from 49 ~tg/g to 45 pg/g. Further, increase of the exposure duration to 60 min caused significant reduction in the DNA content, 36 μg/g. At intensities higher than 10 mT, DNA content decreased significantly even at the shortest exposure of 30 min. At 50 and 100 mT, significant decrease in DNA content was also noticed in response to 30 min exposure; whereas the level of DNA increased after 1 min of MRI exposure to 52 ~g/g, then decreased after 5 min to 46 ~g/g. However, longer durations caused no further decrease in the DNA content. These observations indicate that magnetic fields interact with DNA processes, probably by inhibiting synthesis or stimulating degradation of DNA. This response merits further exploration as a mutational agent for date palm genetic manipulation.展开更多
文摘提高表面等离子体共振(SPR)阵列检测的灵敏度是蛋白质组学和药物发现与开发的迫切需要。提出了一种基于五步移相时域调制相位干涉成像的变曝光时间图像采集法,通过增大信号幅值来提高光强测量信噪比。在一个相位测量周期的5帧图像中,每帧图像都采用不同的曝光时间,使得每帧图像的灰度值达到最大,从而提高光强测量的信噪比,保证相位成像检测的高灵敏度。实验结果表明,通过优化电路设计和对CCD致冷控温,自行设计的CCD传感系统的检测灵敏度达到了1.2×10-6RIU(refractive index unit)。在此基础上,采用变曝光时间图像采集法可有效抑制光散粒噪声和CCD读出噪声,将检测灵敏度再提高35%。该方法不仅适用于SPR相位成像检测,而且还可用于其他定步长和等步长相移法以及帧间灰度值变化大的图像采集及相关检测。
基金The Natural Science Foundation of Jiangsu Province(No.BK2004207)
文摘A double-exposure fabrication method without any intensity shadow mask to fabricate arbitrarily apodized fiber Bragg gratings（ FBGs） with narrow bandwidth is demonstrated by controlling the total ultra violet （UV） irradiation along the grating by varying the speed of a translation stage. The UV source used is a stable continuous intracavity frequency-doubled argonion laser. The parameters （such as length, apodization profile, average index change）of FBGs can be easily changed with this method. The total UV irradiation is kept constant in the doubleexposure process because of the precise control of the exposure time, which ensures that the apodized FBG＇s bandwidth can be extremely narrow. The full width at half maximum （FWHM） bandwidth of the 2-cm-long apodized FBG fabricated by this method is 0. 15 nm with a maximum reflectivity of more than 95%.
基金support of the Carlsberg Foundation[grant no.2008-01-0451]
文摘Heat-shock proteins （HSPs） play an undisputed role for maintaining cellular functioning under environmental challenges and protein denaturing conditions. Compelling evidence points to an evolutionary important role of HSPs and a strict evolutionary control of these proteins as a balance between benefits and costs. While there is a great potential for using HSP expression for detecting natural adaptation and exposure to stress in natural populations, some obstacles and key issues await investigation. From an ecological perspective these key issues needs to be resolved in order to fully appreciate the complex responses and adaptations to stress and to increase our understanding of HSPs and other molecular chaperones for stress adaptation and potential use as biomarkers. Here, the current knowledge and understanding of HSPs is reviewed and a number of key issues including the interpretation of elevated HSP levels, the complications of extrapolating between laboratory and field conditions, the effects of choice of traits and methodology and the larger intra-and extracellular networks of interactions that HSPs participate in are discussed [Current Zoology 56 （6）： 703-713, 2010].
基金supported by the National Basic Research Program of China(No.2012CB955903)
文摘A socio-economic data set on China＇s historical flood losses for the period 1984--2012 was compiled to analyze the exposed population, economy, and crop area as well as the vulnerabilities of the population and economy to floods. The results revealed that the exposed population was approximately 126 persons km-2 per year when taking China as a whole; in terms of the economy, potential losses due to floods were estimated to be approximately 1.49 million C/W4 km 2 and the crop area exposed to floods covered 153 million hm2 per year. China＇s total exposure to floods significantly increased over the analysis period. The areas that showed the higher exposure were mainly located along the east coast. The population＇s vulnerability to floods showed a significantly increasing trend, however, the economic vulnerability showed a decreasing trend. The populations and economies that were most vulnerable to floods were in Hunan, Anhui, Chongqing, Jiangxi, and Hubei provinces. The municipalities of Shanghai, Beijing, and Tianjin showed the lowest vulnerabilities to floods.
文摘Kinetics of color change in tomato purees dried using microwave and conventional method were investigated. For this purpose, the color parameters of Hunter L,a,b and browning index （A42o）, and estimated values of chroma, hue angle, AE, Hunter a/b and a ~ b were examined. The changes in color of tomato samples followed both zero and first order kinetic models to describe visual color changes, and ＆E parameters followed first order kinetic. It was concluded that Hunter axb parameters can be used adequately to follow up the color change of tomato samples during the drying.
文摘Plant stress caused by exposure to magnetic fields （MF） induces modifications at molecular level, particularly in DNA synthesis, structure, and function. The objective of this study was to determine the effect of various doses of non-ionizing radiation of magnetic field on date palm （Phoenix dactylifera L.） based on DNA content. Date palm seedlings （cv. Khalas） established for 2 weeks on filter paper were subjected to static magnetic field and alternating magnetic field. Static magnetic fields （SMF） were applied at 10, 50 and 100 mT for 30, 60, 120, 180, 240 and 360 min; while alternating magnetic field applied by magnetic resonance imaging （MRI） at 1500 mT for 1, 5, 10 and 15 min. The seedlings were grown in potting soil following exposure for 4 weeks after which DNA was extracted from leaves and its content was determined. Generally, the exposure to magnetic field caused reduction in the content of DNA. The lowest exposure time tested, 30 rain, was sufficient to induce reduction in DNA content. This was true even at the lowest intensity, 10 mT. This dosage caused the DNA content to decrease from 49 ~tg/g to 45 pg/g. Further, increase of the exposure duration to 60 min caused significant reduction in the DNA content, 36 μg/g. At intensities higher than 10 mT, DNA content decreased significantly even at the shortest exposure of 30 min. At 50 and 100 mT, significant decrease in DNA content was also noticed in response to 30 min exposure; whereas the level of DNA increased after 1 min of MRI exposure to 52 ~g/g, then decreased after 5 min to 46 ~g/g. However, longer durations caused no further decrease in the DNA content. These observations indicate that magnetic fields interact with DNA processes, probably by inhibiting synthesis or stimulating degradation of DNA. This response merits further exploration as a mutational agent for date palm genetic manipulation.
