Ceramides are important signaling molecules involved in a variety of cellular processes, including cell growth, differentiation, and apoptosis. Currently, different methods are used for ceramide analysis, some of whic...Ceramides are important signaling molecules involved in a variety of cellular processes, including cell growth, differentiation, and apoptosis. Currently, different methods are used for ceramide analysis, some of which are insensitive or cumbersome. This paper described methods utilizing thin layer chromatography (TLC) and high-performance liquid chromatography (HPLC) followed by evaporative light scattering detection (ELSD) to detect ceramide directly in cell extracts without derivatization, which was proved to be efficient and reproducible. Five kinds of ceramides were used as standards. Both TLC and normal-phase HPLC/ELSD results indicate that yeast contains several kinds of ceramides.展开更多
A high-performance liquid chromatography analysis method with an evaporative light-scattering detector has been developed for the separation and quantitative analysis of free fatty acids in biological matrices. Core-s...A high-performance liquid chromatography analysis method with an evaporative light-scattering detector has been developed for the separation and quantitative analysis of free fatty acids in biological matrices. Core-shell reversed-phase high-performance liquid chromatography separation of 10 free fatty acids is achieved within 10.5 min using a methanol/water (0.05% trifluoroacetic acid) eluent gradient. After optimization, the drift tube and nebulization temperature of the evaporative light-scattering detector was set at 35°C, nitrogen flow-rate at 1.1 standard liter per minute and column temperature at 25°C. All calibration curves showed good regression (r2 > 0.9975). A validation procedure following the International Conference on Harmonisation guidelines was implemented to certify the method. Relative standard deviations did not exceed 1.5% and 4.25% for repeatability and reproducibility respectively.展开更多
In recent years, analyses of sweat have become more popular since it doesn't require invasive sampling procedures. Although blood still remains the golden standards in clinical, analyses of other common body fluid...In recent years, analyses of sweat have become more popular since it doesn't require invasive sampling procedures. Although blood still remains the golden standards in clinical, analyses of other common body fluids,such as sweat, have become increasingly important. Because the compositions of sweat and blood are osmotically related, the content of certain metabolites in sweat can directly reflect the disease. Sweat detection can be used as an alternative to blood detection and allows continuous monitoring. Increased development of wearable sensors makes it possible for continuous sweat detection. Here, this paper gave a review about the sweat detection methods, such as fluorescence sensing, electrochemical sensing and colorimetric sensing. The advantages and disadvantages of each method and their developing trend in sweat detection were summarized. Then, for the problem of continuous sweat sampling, three methods(capillary force, hydrogel osmotic pump, evaporationdriven micropump) were introduced through different structures of microfluidic chip, and the level of sweat collection and transport achieved by related research was demonstrated. This review aims to provide guidance for future research in sweat detection and stimulate further interest in continuous monitoring of sweat using microfluidic chip.展开更多
Based on the data of daily average temperature and evaporation in Huanren County from 1953 to 2012, the changing characteristics and trends of temperature and evaporation were analyzed by using climatic tendency rate ...Based on the data of daily average temperature and evaporation in Huanren County from 1953 to 2012, the changing characteristics and trends of temperature and evaporation were analyzed by using climatic tendency rate and sliding Ttest method. The results showed that annual av- erage temperature in Huanren County showed a significant increasing trend in recent 60 years, and its linear tendency rate was 0.26 ℃/10 a. Tem- perature increase was in other seasons except for summer. There was a sudden change in annual average temperature in 1987, and winter average temperature changed suddenly in 1969 and 1985, while there were no sudden changes in average temperature in other seasons. Annual average evaporation also decreased, and its linear trend rate was -8.19 mm/10 a; average evaporation tended to decrease in spring and summer and in- creased in autumn and winter. In a word, the climate tended to be warm and dry in Huanren County.展开更多
Modified refractivity (M) profile is an important parameter to describe the atmospheric refraction environment,as well as a key factor in uniquely evaluating electromagnetic propagation effects.In order to improve the...Modified refractivity (M) profile is an important parameter to describe the atmospheric refraction environment,as well as a key factor in uniquely evaluating electromagnetic propagation effects.In order to improve the model-derived M profile in stable (especially very stable) conditions,three nonlinear similarity functions,namely BH91,CB05,SHEBA07,are introduced in this paper to improve the original Babin_V25 model,and the performances of these modified models are verified based on the hydrometeorological observations from tower platforms,which are finally compared with the original Babin_V25 model and Local_HYQ92 model.Results show that introducing nonlinear similarity functions can significantly improve the model-derived M profile;especially,the newly developed SHEBA07 functions manage to reduce the predicted root mean square (rms) differences of M and M slope (for both 0-5m and 5-40m) by 64.5%,16.6%,and 60.4%,respectively in stable conditions.Unfortunately,this improved method reacts little on the evaporation duct height;in contrast,Local_HYQ92 model is capable of reducing the predicted rms differences of M,M slope (for both 0-5m and 5-40m),and evaporation duct height by 76.7%,40.2%,83.7%,and 58.0% respectively.Finally,a new recommendation is made to apply Local_HYQ92 and Babin_SHEBA07 in very stable conditions considering that M slope is more important than evaporation duct height and absolute M value in uniquely determining electromagnetic propagation effects.展开更多
文摘Ceramides are important signaling molecules involved in a variety of cellular processes, including cell growth, differentiation, and apoptosis. Currently, different methods are used for ceramide analysis, some of which are insensitive or cumbersome. This paper described methods utilizing thin layer chromatography (TLC) and high-performance liquid chromatography (HPLC) followed by evaporative light scattering detection (ELSD) to detect ceramide directly in cell extracts without derivatization, which was proved to be efficient and reproducible. Five kinds of ceramides were used as standards. Both TLC and normal-phase HPLC/ELSD results indicate that yeast contains several kinds of ceramides.
基金financially supported by“Laval Agglomération”and the“Conseil Départemental de la Mayenne”.
文摘A high-performance liquid chromatography analysis method with an evaporative light-scattering detector has been developed for the separation and quantitative analysis of free fatty acids in biological matrices. Core-shell reversed-phase high-performance liquid chromatography separation of 10 free fatty acids is achieved within 10.5 min using a methanol/water (0.05% trifluoroacetic acid) eluent gradient. After optimization, the drift tube and nebulization temperature of the evaporative light-scattering detector was set at 35°C, nitrogen flow-rate at 1.1 standard liter per minute and column temperature at 25°C. All calibration curves showed good regression (r2 > 0.9975). A validation procedure following the International Conference on Harmonisation guidelines was implemented to certify the method. Relative standard deviations did not exceed 1.5% and 4.25% for repeatability and reproducibility respectively.
基金supported by the National Key Research and Development Program of China (No. 2020YFC2004600, No. 2018YFE0205000)the National Natural Science Foundation of China (No. 81571766)+1 种基金the Natural Science Foundation of Tianjin (No. 17JCYBJC24400)the 111 Project of China (No. B07014)。
文摘In recent years, analyses of sweat have become more popular since it doesn't require invasive sampling procedures. Although blood still remains the golden standards in clinical, analyses of other common body fluids,such as sweat, have become increasingly important. Because the compositions of sweat and blood are osmotically related, the content of certain metabolites in sweat can directly reflect the disease. Sweat detection can be used as an alternative to blood detection and allows continuous monitoring. Increased development of wearable sensors makes it possible for continuous sweat detection. Here, this paper gave a review about the sweat detection methods, such as fluorescence sensing, electrochemical sensing and colorimetric sensing. The advantages and disadvantages of each method and their developing trend in sweat detection were summarized. Then, for the problem of continuous sweat sampling, three methods(capillary force, hydrogel osmotic pump, evaporationdriven micropump) were introduced through different structures of microfluidic chip, and the level of sweat collection and transport achieved by related research was demonstrated. This review aims to provide guidance for future research in sweat detection and stimulate further interest in continuous monitoring of sweat using microfluidic chip.
文摘Based on the data of daily average temperature and evaporation in Huanren County from 1953 to 2012, the changing characteristics and trends of temperature and evaporation were analyzed by using climatic tendency rate and sliding Ttest method. The results showed that annual av- erage temperature in Huanren County showed a significant increasing trend in recent 60 years, and its linear tendency rate was 0.26 ℃/10 a. Tem- perature increase was in other seasons except for summer. There was a sudden change in annual average temperature in 1987, and winter average temperature changed suddenly in 1969 and 1985, while there were no sudden changes in average temperature in other seasons. Annual average evaporation also decreased, and its linear trend rate was -8.19 mm/10 a; average evaporation tended to decrease in spring and summer and in- creased in autumn and winter. In a word, the climate tended to be warm and dry in Huanren County.
基金Key project of the National Natural Science Foundation of China(4083095841005029)the "973" National Basis Research and Development Program of China (2009CB421502)
文摘Modified refractivity (M) profile is an important parameter to describe the atmospheric refraction environment,as well as a key factor in uniquely evaluating electromagnetic propagation effects.In order to improve the model-derived M profile in stable (especially very stable) conditions,three nonlinear similarity functions,namely BH91,CB05,SHEBA07,are introduced in this paper to improve the original Babin_V25 model,and the performances of these modified models are verified based on the hydrometeorological observations from tower platforms,which are finally compared with the original Babin_V25 model and Local_HYQ92 model.Results show that introducing nonlinear similarity functions can significantly improve the model-derived M profile;especially,the newly developed SHEBA07 functions manage to reduce the predicted root mean square (rms) differences of M and M slope (for both 0-5m and 5-40m) by 64.5%,16.6%,and 60.4%,respectively in stable conditions.Unfortunately,this improved method reacts little on the evaporation duct height;in contrast,Local_HYQ92 model is capable of reducing the predicted rms differences of M,M slope (for both 0-5m and 5-40m),and evaporation duct height by 76.7%,40.2%,83.7%,and 58.0% respectively.Finally,a new recommendation is made to apply Local_HYQ92 and Babin_SHEBA07 in very stable conditions considering that M slope is more important than evaporation duct height and absolute M value in uniquely determining electromagnetic propagation effects.
