Enzyme-induced carbonate precipitation (EICP) is an emerging technique to improve the soil and most studies are carried out at room temperature. However, considering some foundations are in high-temperature environmen...Enzyme-induced carbonate precipitation (EICP) is an emerging technique to improve the soil and most studies are carried out at room temperature. However, considering some foundations are in high-temperature environments (>40 ℃), the higher urease activity at high temperature results in the solidification inhomogeneity, limiting the application of EICP. The higher urease activity at high temperature hampers the application of EICP because of solidification inhomogeneity. The garlic extract has been used as a type of urease inhibitor in medical science and food engineering. Here, we propose to use it to control urease activity for sand solidification at high temperature. The effects of garlic extract addition on urease activity and precipitation rates for calcium carbonate (CaCO_(3)) were studied. Extra tests were conducted to study the effect of garlic extract addition on the solidification homogeneity. The results showed that the garlic extract addition significantly decreased urease activity. To reduce the rate of CaCO3 precipitation at different temperatures, a suitable concentration of garlic extract was necessary to obtain a suitable urease activity. In the sand solidification test, garlic extract addition resulted in a smaller difference in sonic time values or CaCO_(3) contents at different parts of samples. The improved solidification homogeneity can achieve higher strength. The correlation between sonic time values and CaCO_(3) content was higher than that between CaCO3 content and strength. Appropriate concentrations of garlic extract were obtained at 35 ℃, 40℃, 45 ℃, 50 ℃, and 55 ℃. The proposed garlic extract addition method was significant to improve the homogeneity of solidified soil in practical engineering applications.展开更多
Daily precipitation and temperature records at 13 stations for the period 1960-2008 were analyzed to identify climatic change and possible effects of urbanization on low-temperature precipitation [LTP, precipitation ...Daily precipitation and temperature records at 13 stations for the period 1960-2008 were analyzed to identify climatic change and possible effects of urbanization on low-temperature precipitation [LTP, precipitation of ≥ 0.1 mm d^-1 occurring under a daily minimum temperature (Tmin) of ≤ 0℃] in the greater Beijing region (B JR), where a rapid process of urbaniza tion has taken place over the last few decades. The paper provides a climatological overview of LTP in B JR. LTP contributes 61.7% to the total amount of precipitation in B JR in the cold season (November-March). There is a slight increasing trend [1.22 mm (10 yr)^-1] in the amount of total precipitation for the cold season during 1960-2008. In contrast, the amount of LTP decreases by 0.6 mm (10 yr)^-1. The warming rate of Train in B JR is 0.66℃ (10 yr)^-1. Correspondingly, the frequency of LTP decreases with increasing Tmin by -0.67 times per ℃. The seasonal frequency and amount of LTP in southeast B JR (mostly urban sites) are 17%-20% less than those in the northwestern (rural and montane sites). The intensity of LTP for the urban sites and northeastern B JR exhibited significant enhancing trends [0.18 and 0.15 mm d^- 1 (10 yr)^- 1, respectively]. The frequency of slight LTP (〈0.2 mm d^-1) significantly decreased throughout B JR [by about -15.74% (10 yr)^-1 in the urban area and northeast B JR], while the contribution of the two heaviest LTP events to total LTP amount significantly increased by 3.2% (10 yr) ^-1.展开更多
[ Objective ] This study aimed to investigate the optimal method for extracting RNA from roots of medicinal plant herba violae by comparing the effects of liquid nitrogen grinding method and low-temperature sectioning...[ Objective ] This study aimed to investigate the optimal method for extracting RNA from roots of medicinal plant herba violae by comparing the effects of liquid nitrogen grinding method and low-temperature sectioning method on RNA extraction. [ Method] Roots of herba violae were respectively crushed by using liquid nitrogen grinding method and low-temperature sectioning method to extract RNA. The extraction effects of these two methods were compared based on detec- tion of RNA concentration, purity and integrity and amplification of GAPDH gene by RT-PCR. [Result] The concentration of RNA extracted by liquid nitrogen grinding method and low-temperature sectioning method was 1.21 and 3.57 p^g/~, respectively. Both RNA extracted by these two methods showed two distinct bands after agarose gel electrophoresis. The ratio of brightness of the 28S rRNA to the 18S rRNA bands was greater than 1. PCR amplification showed that the length of GAPDH gene was about 230 bp, which was consistent with the expected result. [ Conclusion ] The experimental results indicated that using low-tempera ture sectioning method to crush the roots of herba violae can meet the needs of most molecular biological experiments including gene cloning and expression analysis, which is an effective and simple method for extracting RNA from plant roots.展开更多
Tributyl phosphate(TBP) was employed for the Bi(Ⅲ) extraction from hydrochloric acid medium.The effects of extraction time and material concentration were examined.The replacement mechanism between the anion(Cl^-) an...Tributyl phosphate(TBP) was employed for the Bi(Ⅲ) extraction from hydrochloric acid medium.The effects of extraction time and material concentration were examined.The replacement mechanism between the anion(Cl^-) and TBP was proposed for extraction.The results show the species extracted into the organic phase were found to be mainly BiCl_3·x TBP(x=2 or 3).Thermodynamic parameters of the extraction reaction were obtained from the thermodynamics analysis,which illustrates that higher temperatures show a negative effect on the extraction.Extraction isotherm was obtained with 2.16 mol/L TBP for a typical solution containing 0.1 mol/L of bismuth and 1.0 mol/L of hydrochloric acid.About 98.5 % of bismuth has been extracted from the leaching solution under the optimum condition.Moreover,oxalate was explored as a precipitation stripping agent for BiCl_3·x TBP(x=2 or 3) complexes,by which Bi(Ⅲ) was stripped in the form of Bi_2(C_2O_4)_3·7H_2O.A stripping efficiency of 99.3% was obtained in only one stage at the phase ratio of 1 and TBP also could be recycled.Therefore,the method is an efficient,effective and highly selective approach to extract Bi(Ⅲ) and to recover metal bismuth.展开更多
Seabuckthorn seed meal(SSM) is a waste of oil extraction industry that rich in protein. In order to seek suitable protein extraction method, three different deep eutectic solvents(DESs)(including choline chlorideglyce...Seabuckthorn seed meal(SSM) is a waste of oil extraction industry that rich in protein. In order to seek suitable protein extraction method, three different deep eutectic solvents(DESs)(including choline chlorideglycerol, choline chloride-oxalic acid and choline chloride-urea) were developed for extracting protein from SSM and compared with alkaline. Result indicated that alkaline could effectively extract 56.9% protein from SSM and its protein content was 73.1%, higher than DES at 31.0%-41.4% and 64.3%-67.5%, respectively. However, compared to alkali, DES led to a product with less β-sheet, more β-turn, more essential amino acids, higher total amino acid content, especially choline chloride-urea which extracted protein showing an integrated and similar protein weight distribution compared to SSM. Also, this protein extracted chloride-urea showed a highest digestibility in vitro(by pepsin)(54.2%). These results indicated that choline chloride-urea extraction is better than alkaline extraction for SSM.展开更多
A simple and high-throughput method to simultaneously determine selected benzodiazepines (i.e., diazepam, lorazepam, clonazepam, and bromazepam) in urine was developed and validated. The entire methodology consisted o...A simple and high-throughput method to simultaneously determine selected benzodiazepines (i.e., diazepam, lorazepam, clonazepam, and bromazepam) in urine was developed and validated. The entire methodology consisted of the application of an innovative extraction/cleanup procedure, namely liquid-liquid extraction with low-temperature partitioning (LLE-LTP), and analysis by liquid chromatography combined with high-resolution mass spectrometry (LC-HRMS). The LLE-LTP procedure was optimized via factorial design and by evaluating crucial variables, specifically the freezing mode (either slow or fast), the urine/acetonitrile volume ratio, and the sample ionic strength. The benzodiazepines were quantified using matrix-matched calibration curves where the following parameters were assessed by validation protocol: in general, linearity range of 17 - 200 μg?L–1 (r > 0.9957);limits of detection lower than 5 μg?L–1;relative standard deviations (RSD) lower than 12.5%;and accuracy ranging from 72.3 to 117%. To test this procedure’s performance, the method was applied to determine the content of diazepam in actual urine samples. The validation results obtained for the method demonstrated that the present methodology could be potentially applied in proficient laboratories as a routine approach for determining benzodiazepines compounds content in urine.展开更多
Objective:To optimize the technological conditions of ultrasonic-assisted extraction of Amomum longiligulare T.L.Wu polysaccharides and increase the yield of polysaccharides.Methods:The polysaccharide was prepared by ...Objective:To optimize the technological conditions of ultrasonic-assisted extraction of Amomum longiligulare T.L.Wu polysaccharides and increase the yield of polysaccharides.Methods:The polysaccharide was prepared by water extraction and alcohol precipitation method,and the yield of polysaccharide was taken as an index.The effects of ultrasonic time,extraction times,ultrasonic temperature,and water-to-material ratio on polysaccharide yield were investigated through a single factor experiment.Combined experimental design and response surface analysis were used to optimize the extraction process of Amomum longiligulare T.L.Wu polysaccharides.Results:The optimum conditions of ultrasonic-assisted extraction were determined as follows:extraction time of 29 min,three extraction times,water bath extraction temperature of 68℃,water-to-material ratio of 15:1;under these conditions,the polysaccharide yield was 10.69%.Conclusion:The results are close to the predicted values of the model.This optimization test is effective and feasible,and provides a reference for the related research of Amomum longiligulare T.L.Wu.展开更多
Objective:Pretreatment of biological samples is the most critical step in pharmacokinetic studies,especially pre-treatment of plasma samples.The pretreatment of biological samples in pharmacokinetic study of Tradition...Objective:Pretreatment of biological samples is the most critical step in pharmacokinetic studies,especially pre-treatment of plasma samples.The pretreatment of biological samples in pharmacokinetic study of Traditional Chinese Medicines (TCM) is difficult due to the complexity of the ingredients.An organic solvent system ethyl acetate:acetone (10:1) solution used for liquid-liquid extraction has been developed in this study and compared with the commonly used protein precipitation method.Methods:Rats,Beagle dogs and humans plasma samples were adopted in this study in order to demonstrate the universality of the pretreatment method.Feasibility of this pretreatment method was also verified through its application to the pharmacokinetics of rhubarb in rats.Results:According to the results of extraction recovery matrix effect,it was indicated that the liquid-liquid extraction methods with new organic solvent might be suitable for variety of structures of compounds and various types of plasma samples.The pharmacokinetic study result showed that the developed pretreatment method could successfully be used for simultaneous determination of three active compounds modin,emodin-8-O-β-D-glucopyranoside (EDG) and rhein in rat plasma with high sensitivity,accuracy,and recovery by liquid chromatography tandem mass spectrometry (LC-MS/MS).Conclusion:The pretreatment method of liquid-liquid extraction methods with new organic solvent could be successfully applied for multi-component pharmacokinetics of TCM.展开更多
The occurrence characteristics of shale oil are of great significance to the movability of shale oil.In this study,the occurrence characteristics of oil in the shale matrix at Funing Formation shale in Subei Basin wer...The occurrence characteristics of shale oil are of great significance to the movability of shale oil.In this study,the occurrence characteristics of oil in the shale matrix at Funing Formation shale in Subei Basin were quantitatively evaluated by organic geochemistry and microscopic pore structure characterization experiments.The Multiple Isothermal Stages Pyrolysis(MIS)experiment results show that the content of total oil,adsorbed oil,and free oil in the shales are 3.15-11.25 mg/g,1.41-4.95 mg/g,and 1.74-6.51 mg/g,respectively.among which the silicon-rich shale has the best oil-bearing.The relative content of free oil shows an increasing trend in pores with pore diameters greater than 3 nm.When the relative content of free oil reaches 100%,the pore size of silicon-rich shale is about 200 nm,while that of calcium-rich shale,clay-rich shale,and siliceous mixed shale is about 10 nm.The occurrence law of adsorbed oil is opposite to that of free oil,which indicates that shale oil will occur in the pores and fractures in a free state in a more extensive pore size range(>200 nm).This study also enables us to further understand the occurrence characteristics of shale oil under the interaction of occurrence state and occurrence space.展开更多
基金funded by the National Natural Science Foundation of China(Grant No.51578147)the Science and Technology Department of Ningxia(Grant No.2020BFG02014)the Trans-portation Department of Ningxia(Grant No.202000173).
文摘Enzyme-induced carbonate precipitation (EICP) is an emerging technique to improve the soil and most studies are carried out at room temperature. However, considering some foundations are in high-temperature environments (>40 ℃), the higher urease activity at high temperature results in the solidification inhomogeneity, limiting the application of EICP. The higher urease activity at high temperature hampers the application of EICP because of solidification inhomogeneity. The garlic extract has been used as a type of urease inhibitor in medical science and food engineering. Here, we propose to use it to control urease activity for sand solidification at high temperature. The effects of garlic extract addition on urease activity and precipitation rates for calcium carbonate (CaCO_(3)) were studied. Extra tests were conducted to study the effect of garlic extract addition on the solidification homogeneity. The results showed that the garlic extract addition significantly decreased urease activity. To reduce the rate of CaCO3 precipitation at different temperatures, a suitable concentration of garlic extract was necessary to obtain a suitable urease activity. In the sand solidification test, garlic extract addition resulted in a smaller difference in sonic time values or CaCO_(3) contents at different parts of samples. The improved solidification homogeneity can achieve higher strength. The correlation between sonic time values and CaCO_(3) content was higher than that between CaCO3 content and strength. Appropriate concentrations of garlic extract were obtained at 35 ℃, 40℃, 45 ℃, 50 ℃, and 55 ℃. The proposed garlic extract addition method was significant to improve the homogeneity of solidified soil in practical engineering applications.
基金supported by National Natural Science Foundation of China(Grant No.41075063)Chinese Academy of Sciences Strategic Priority Research Program(Grant No.XDA05090000)National Basic Research Program of China(Grant No.2012CB956200)
文摘Daily precipitation and temperature records at 13 stations for the period 1960-2008 were analyzed to identify climatic change and possible effects of urbanization on low-temperature precipitation [LTP, precipitation of ≥ 0.1 mm d^-1 occurring under a daily minimum temperature (Tmin) of ≤ 0℃] in the greater Beijing region (B JR), where a rapid process of urbaniza tion has taken place over the last few decades. The paper provides a climatological overview of LTP in B JR. LTP contributes 61.7% to the total amount of precipitation in B JR in the cold season (November-March). There is a slight increasing trend [1.22 mm (10 yr)^-1] in the amount of total precipitation for the cold season during 1960-2008. In contrast, the amount of LTP decreases by 0.6 mm (10 yr)^-1. The warming rate of Train in B JR is 0.66℃ (10 yr)^-1. Correspondingly, the frequency of LTP decreases with increasing Tmin by -0.67 times per ℃. The seasonal frequency and amount of LTP in southeast B JR (mostly urban sites) are 17%-20% less than those in the northwestern (rural and montane sites). The intensity of LTP for the urban sites and northeastern B JR exhibited significant enhancing trends [0.18 and 0.15 mm d^- 1 (10 yr)^- 1, respectively]. The frequency of slight LTP (〈0.2 mm d^-1) significantly decreased throughout B JR [by about -15.74% (10 yr)^-1 in the urban area and northeast B JR], while the contribution of the two heaviest LTP events to total LTP amount significantly increased by 3.2% (10 yr) ^-1.
基金Supported by National Natural Science Foundation of China(81001700)Project of Sichuan Provincial Education Department(11ZB227,11ZB124)Research Project for the Application Foundation of Sichuan Provincial Science and Technology Department(2012JY0081)
文摘[ Objective ] This study aimed to investigate the optimal method for extracting RNA from roots of medicinal plant herba violae by comparing the effects of liquid nitrogen grinding method and low-temperature sectioning method on RNA extraction. [ Method] Roots of herba violae were respectively crushed by using liquid nitrogen grinding method and low-temperature sectioning method to extract RNA. The extraction effects of these two methods were compared based on detec- tion of RNA concentration, purity and integrity and amplification of GAPDH gene by RT-PCR. [Result] The concentration of RNA extracted by liquid nitrogen grinding method and low-temperature sectioning method was 1.21 and 3.57 p^g/~, respectively. Both RNA extracted by these two methods showed two distinct bands after agarose gel electrophoresis. The ratio of brightness of the 28S rRNA to the 18S rRNA bands was greater than 1. PCR amplification showed that the length of GAPDH gene was about 230 bp, which was consistent with the expected result. [ Conclusion ] The experimental results indicated that using low-tempera ture sectioning method to crush the roots of herba violae can meet the needs of most molecular biological experiments including gene cloning and expression analysis, which is an effective and simple method for extracting RNA from plant roots.
基金Project(2011AA061002)supported by the High-Tech Research and Development Program of ChinaProject(2010SK2010)supported by the Key Program of Science and Technology of Hunan Province,ChinaProject supported by the Hunan Nonferrous Metals Fund,China
文摘Tributyl phosphate(TBP) was employed for the Bi(Ⅲ) extraction from hydrochloric acid medium.The effects of extraction time and material concentration were examined.The replacement mechanism between the anion(Cl^-) and TBP was proposed for extraction.The results show the species extracted into the organic phase were found to be mainly BiCl_3·x TBP(x=2 or 3).Thermodynamic parameters of the extraction reaction were obtained from the thermodynamics analysis,which illustrates that higher temperatures show a negative effect on the extraction.Extraction isotherm was obtained with 2.16 mol/L TBP for a typical solution containing 0.1 mol/L of bismuth and 1.0 mol/L of hydrochloric acid.About 98.5 % of bismuth has been extracted from the leaching solution under the optimum condition.Moreover,oxalate was explored as a precipitation stripping agent for BiCl_3·x TBP(x=2 or 3) complexes,by which Bi(Ⅲ) was stripped in the form of Bi_2(C_2O_4)_3·7H_2O.A stripping efficiency of 99.3% was obtained in only one stage at the phase ratio of 1 and TBP also could be recycled.Therefore,the method is an efficient,effective and highly selective approach to extract Bi(Ⅲ) and to recover metal bismuth.
基金the financial support from the National Natural Science Foundation of China (No. 31201416)Science and Technology Research Program of Guangdong Province (No. 2017A01010502)。
文摘Seabuckthorn seed meal(SSM) is a waste of oil extraction industry that rich in protein. In order to seek suitable protein extraction method, three different deep eutectic solvents(DESs)(including choline chlorideglycerol, choline chloride-oxalic acid and choline chloride-urea) were developed for extracting protein from SSM and compared with alkaline. Result indicated that alkaline could effectively extract 56.9% protein from SSM and its protein content was 73.1%, higher than DES at 31.0%-41.4% and 64.3%-67.5%, respectively. However, compared to alkali, DES led to a product with less β-sheet, more β-turn, more essential amino acids, higher total amino acid content, especially choline chloride-urea which extracted protein showing an integrated and similar protein weight distribution compared to SSM. Also, this protein extracted chloride-urea showed a highest digestibility in vitro(by pepsin)(54.2%). These results indicated that choline chloride-urea extraction is better than alkaline extraction for SSM.
基金Conselho Nacional de Desenvolvimento Cientifico e Tecnologico(CNPq)and Fundacao de Amparo a Pesquisa do Estado de Minas Gerais(FAPEMIG)for financial support and research fellowships.
文摘A simple and high-throughput method to simultaneously determine selected benzodiazepines (i.e., diazepam, lorazepam, clonazepam, and bromazepam) in urine was developed and validated. The entire methodology consisted of the application of an innovative extraction/cleanup procedure, namely liquid-liquid extraction with low-temperature partitioning (LLE-LTP), and analysis by liquid chromatography combined with high-resolution mass spectrometry (LC-HRMS). The LLE-LTP procedure was optimized via factorial design and by evaluating crucial variables, specifically the freezing mode (either slow or fast), the urine/acetonitrile volume ratio, and the sample ionic strength. The benzodiazepines were quantified using matrix-matched calibration curves where the following parameters were assessed by validation protocol: in general, linearity range of 17 - 200 μg?L–1 (r > 0.9957);limits of detection lower than 5 μg?L–1;relative standard deviations (RSD) lower than 12.5%;and accuracy ranging from 72.3 to 117%. To test this procedure’s performance, the method was applied to determine the content of diazepam in actual urine samples. The validation results obtained for the method demonstrated that the present methodology could be potentially applied in proficient laboratories as a routine approach for determining benzodiazepines compounds content in urine.
基金National Natural Science Foundation of China(No.81660649)Hainan Medical College Student Innovation and Entrepreneurship Training Program Project(No.201811810007)。
文摘Objective:To optimize the technological conditions of ultrasonic-assisted extraction of Amomum longiligulare T.L.Wu polysaccharides and increase the yield of polysaccharides.Methods:The polysaccharide was prepared by water extraction and alcohol precipitation method,and the yield of polysaccharide was taken as an index.The effects of ultrasonic time,extraction times,ultrasonic temperature,and water-to-material ratio on polysaccharide yield were investigated through a single factor experiment.Combined experimental design and response surface analysis were used to optimize the extraction process of Amomum longiligulare T.L.Wu polysaccharides.Results:The optimum conditions of ultrasonic-assisted extraction were determined as follows:extraction time of 29 min,three extraction times,water bath extraction temperature of 68℃,water-to-material ratio of 15:1;under these conditions,the polysaccharide yield was 10.69%.Conclusion:The results are close to the predicted values of the model.This optimization test is effective and feasible,and provides a reference for the related research of Amomum longiligulare T.L.Wu.
文摘Objective:Pretreatment of biological samples is the most critical step in pharmacokinetic studies,especially pre-treatment of plasma samples.The pretreatment of biological samples in pharmacokinetic study of Traditional Chinese Medicines (TCM) is difficult due to the complexity of the ingredients.An organic solvent system ethyl acetate:acetone (10:1) solution used for liquid-liquid extraction has been developed in this study and compared with the commonly used protein precipitation method.Methods:Rats,Beagle dogs and humans plasma samples were adopted in this study in order to demonstrate the universality of the pretreatment method.Feasibility of this pretreatment method was also verified through its application to the pharmacokinetics of rhubarb in rats.Results:According to the results of extraction recovery matrix effect,it was indicated that the liquid-liquid extraction methods with new organic solvent might be suitable for variety of structures of compounds and various types of plasma samples.The pharmacokinetic study result showed that the developed pretreatment method could successfully be used for simultaneous determination of three active compounds modin,emodin-8-O-β-D-glucopyranoside (EDG) and rhein in rat plasma with high sensitivity,accuracy,and recovery by liquid chromatography tandem mass spectrometry (LC-MS/MS).Conclusion:The pretreatment method of liquid-liquid extraction methods with new organic solvent could be successfully applied for multi-component pharmacokinetics of TCM.
基金This work was financially supported by the National Natural Science Foundation of China(41972123,41922015)the Natural Science Foundation of Shandong Province(ZR2020QD036).
文摘The occurrence characteristics of shale oil are of great significance to the movability of shale oil.In this study,the occurrence characteristics of oil in the shale matrix at Funing Formation shale in Subei Basin were quantitatively evaluated by organic geochemistry and microscopic pore structure characterization experiments.The Multiple Isothermal Stages Pyrolysis(MIS)experiment results show that the content of total oil,adsorbed oil,and free oil in the shales are 3.15-11.25 mg/g,1.41-4.95 mg/g,and 1.74-6.51 mg/g,respectively.among which the silicon-rich shale has the best oil-bearing.The relative content of free oil shows an increasing trend in pores with pore diameters greater than 3 nm.When the relative content of free oil reaches 100%,the pore size of silicon-rich shale is about 200 nm,while that of calcium-rich shale,clay-rich shale,and siliceous mixed shale is about 10 nm.The occurrence law of adsorbed oil is opposite to that of free oil,which indicates that shale oil will occur in the pores and fractures in a free state in a more extensive pore size range(>200 nm).This study also enables us to further understand the occurrence characteristics of shale oil under the interaction of occurrence state and occurrence space.