The standards of plant toxins were separated by a C18 column with gradient elution with 0.1% formic acid/water (V/V) and 0.1% formic acid/acetonitrile (V/V) as mobile phase and acquired by ion mobility-quadrupole time...The standards of plant toxins were separated by a C18 column with gradient elution with 0.1% formic acid/water (V/V) and 0.1% formic acid/acetonitrile (V/V) as mobile phase and acquired by ion mobility-quadrupole time of flight mass spectrometry (IM-QTOF MS) in positive ion mode. A database of 308 plant toxins including retention time, collision cross-section (CCS) and its fragment ions was established. Honey dissolved in water or herbal beverage was extracted by acetonitrile and purified with PSA sorbent, and then acquired by ultrahigh-performance liquid chromatography IM-QTOFMS. The acquired data were processed by comparing with the database we established to confirm the target compounds. The average recoveries for samples at two levels ranged from 60.6% - 120.1%, with relative standard deviation (n = 6) less than 25%. The limit of quantitation for plant toxins ranged from 1 - 20 μg/kg. The developed screening method was used in determination of honey, herbal beverage and honey flavored tea beverage samples. The results showed that berberine was detected in one honey with 1 μg/kg and caffeine was present in some beverages with the concentration from 200 and 5500 μg/kg. This method could meet the requirement for rapid screening of plant toxins in honey and herbal beverage. It can be used for the quality control of honey and herbal beverage in enterprises or quality inspection departments. It also can be used in the rapid screening of food poisoning.展开更多
Objective:Cholesteryl esters(CEs)are composed of various fatty acyl chains attached to the hydroxyl groups of cholesterol,and abnormalities in their metabolism are related to many diseases.This study aimed to develop ...Objective:Cholesteryl esters(CEs)are composed of various fatty acyl chains attached to the hydroxyl groups of cholesterol,and abnormalities in their metabolism are related to many diseases.This study aimed to develop an ultrahigh-performance liquid chromatography-quadrupole exactive mass spectrometry(UPLC-Q-Exactive MS)method to identify the CEs in plasma.Methods:First,the MS fragmentation patterns were investigated using seven commercial CE standards.Then,the CEs in plasma were characterized through the accurate mass data of precursor ions and characteristic product ions.A strategy of step-by-step m/z scans in a narrow range was proposed to identify more trace CEs by the full-scan data-dependent MS/MS(ddMS2)mode.Results:A total of 50 CE species consisting of 55 regioisomers were identified in human plasma.Among them,two species were reported for the first time.Conclusion:This study is the most comprehensive identification of CE species in human plasma to date.These results will contribute to the in-depth profiling of CEs in human plasma and provide guidance for animal model selection when studying lipid-related diseases.展开更多
Background:Drying is a necessary component of traditional Chinese medicine extracts.The heating principle of microwave vacuum drying is different from that of the conventional heat method.However,at present,there is p...Background:Drying is a necessary component of traditional Chinese medicine extracts.The heating principle of microwave vacuum drying is different from that of the conventional heat method.However,at present,there is paucity of information on the drying process of traditional Chinese medicine extract by microwave vacuum drying,and the results of such process are unclear.Methods:To study the dynamic changes in the chemical characteristics of microwave vacuum drying under different drying conditions,ultrahigh-performance liquid chromatography fingerprint profiles were established using Radix isatidis extract as a model drug and analyzed using similarity analysis,partial least squares-discriminant analysis,and semi-quantitative analysis.In addition,a backpropagation artificial neural network model was developed to predict the moisture ratio of the drying process.Results:Qualitative results showed that the similarity between different drying conditions was greater than 0.95,and 2 amino acid components(peaks 5 and 6)affected by process fluctuations were screened out.The quantitative results showed that the mass concentration of component 1 fluctuated after drying,while that of component 2 increased.The optimal backpropagation artificial neural network model structure used to predict the moisture ratio was 5-4-1,with regression and mean squared error values of 0.996 and 0.0003,respectively,after training,which were well fitted and had a strong approximation ability.Conclusion:Upon comparison of fingerprints and the evaluation of statistical methods,common components of Radix isatidis extract had little variation under different drying conditions,and the selected components provided a reference for the establishment of process evaluation indexes.The establishment of backpropagation artificial neural network provides a theoretical basis for the application of microwave vacuum drying technology and online monitoring of moisture ratio.展开更多
In this study,a fully precast steel—ultrahigh performance concrete(UHPC)lightweight composite bridge(LWCB)was proposed based on Mapu Bridge,aiming at accelerating construction in bridge engineering.Cast-in-place join...In this study,a fully precast steel—ultrahigh performance concrete(UHPC)lightweight composite bridge(LWCB)was proposed based on Mapu Bridge,aiming at accelerating construction in bridge engineering.Cast-in-place joints are generally the controlling factor of segmental structures.Therefore,an innovative girder-to-girder joint that is suitable for LWCB was developed.A specimen consisting of two prefabricated steel—UHPC composite girder parts and one post-cast joint part was fabricated to determine if the joint can effectively transfer load between girders.The flexural behavior of the specimen under a negative bending moment was explored.Finite element analyses of Mapu Bridge showed that the nominal stress of critical sections could meet the required stress,indicating that the design is reasonable.The fatigue performance of the UHPC deck was assessed based on past research,and results revealed that the fatigue performance could meet the design requirements.Based on the test results,a crack width prediction method for the joint interface,a simplified calculation method for the design moment,and a deflection calculation method for the steel—UHPC composite girder in consideration of the UHPC tensile stiffness effect were presented.Good agreements were achieved between the predicted values and test results.展开更多
A comprehensive experimental design was developed to determine suitable conditions(volume, percentage of solvent, extraction temperature) for the ethanol extraction of phenolic compounds from ten tropical woody plants...A comprehensive experimental design was developed to determine suitable conditions(volume, percentage of solvent, extraction temperature) for the ethanol extraction of phenolic compounds from ten tropical woody plants. Wenge, angelim vermelho, zebrano, merbau,tigerwood, angelim pedra, jatoba, angelim amargoso,massaranduba, and doussie woods were used in experiments. The effects of three independent variables and their interactions on the yields of cinnamic and benzoic acid derivates were analyzed using UHPLC-PDA. The most significant parameters were found to be solvent percentage,extraction volume, and extraction temperature. Optimal conditions for the extraction of phenolic compound contents were an 80℃ extraction temperature, a 30 mL extraction volume, and the use of pure water as the extraction solvent. The tested species of woods contained mainly cinnamic acid derivates. Water extracts after hydrolysis contained greater amounts of cinnamic acid derivates than those extracts from non-hydrolyzed material.The total phenolics content was highest in water extracts of tigerwood, wenge and merbau;however, the extract of merbau wood was a stronger radical scavenger in ABTS?áassays: 34.11 ± 0.02 mM Trolox equivalents per g of dry extract. The main compounds possessing antioxidant activity in the extracts of vermelho wood assessed by UHPLC analysis were hydroxycinnamic acids.展开更多
目的·研发一种具有高通量、高灵敏度和准确度的神经酰胺定量分析方法。方法·应用超高效液相色谱串联三重四极杆质谱(ultrahigh-performance liquid chromatography tandem triple-quadrupole mass spectrometry,UHPLC-MS)对1...目的·研发一种具有高通量、高灵敏度和准确度的神经酰胺定量分析方法。方法·应用超高效液相色谱串联三重四极杆质谱(ultrahigh-performance liquid chromatography tandem triple-quadrupole mass spectrometry,UHPLC-MS)对14种神经酰胺进行定量分析,使用的色谱柱为ZORBAX Eclipse plus C8(2.1 mm×150 mm,1.8μm),流动相A为超纯水,流动相B为甲醇,流动相A和B中均加入2.5 mmol/L乙酸铵。采用多反应监测模式和正离子模式分析神经酰胺。结果·该方法能在10 min内定量分析14种神经酰胺,检测限(limit of detection,LOD)和定量限(limit of quantification,LOQ)分别为0.06~0.42 nmol/L和0.17~1.26 nmol/L。准确度范围为73.02%~122.39%,保留时间和积分面积的相对标准偏差分别为0.07%~0.54%和2.26%~13.98%。结论·基于UHPLC-MS技术的神经酰胺定量分析方法灵敏度高、重现性好、分析效率高,可用于检测细胞等生物样品中的神经酰胺含量。展开更多
文摘The standards of plant toxins were separated by a C18 column with gradient elution with 0.1% formic acid/water (V/V) and 0.1% formic acid/acetonitrile (V/V) as mobile phase and acquired by ion mobility-quadrupole time of flight mass spectrometry (IM-QTOF MS) in positive ion mode. A database of 308 plant toxins including retention time, collision cross-section (CCS) and its fragment ions was established. Honey dissolved in water or herbal beverage was extracted by acetonitrile and purified with PSA sorbent, and then acquired by ultrahigh-performance liquid chromatography IM-QTOFMS. The acquired data were processed by comparing with the database we established to confirm the target compounds. The average recoveries for samples at two levels ranged from 60.6% - 120.1%, with relative standard deviation (n = 6) less than 25%. The limit of quantitation for plant toxins ranged from 1 - 20 μg/kg. The developed screening method was used in determination of honey, herbal beverage and honey flavored tea beverage samples. The results showed that berberine was detected in one honey with 1 μg/kg and caffeine was present in some beverages with the concentration from 200 and 5500 μg/kg. This method could meet the requirement for rapid screening of plant toxins in honey and herbal beverage. It can be used for the quality control of honey and herbal beverage in enterprises or quality inspection departments. It also can be used in the rapid screening of food poisoning.
基金supported by National Natural Science Foundation of China(No.81874309,No.81903901 and No.81803717)the Youth Foundation of the Zhejiang Academy of Medical Sciences(No.2020Y003).
文摘Objective:Cholesteryl esters(CEs)are composed of various fatty acyl chains attached to the hydroxyl groups of cholesterol,and abnormalities in their metabolism are related to many diseases.This study aimed to develop an ultrahigh-performance liquid chromatography-quadrupole exactive mass spectrometry(UPLC-Q-Exactive MS)method to identify the CEs in plasma.Methods:First,the MS fragmentation patterns were investigated using seven commercial CE standards.Then,the CEs in plasma were characterized through the accurate mass data of precursor ions and characteristic product ions.A strategy of step-by-step m/z scans in a narrow range was proposed to identify more trace CEs by the full-scan data-dependent MS/MS(ddMS2)mode.Results:A total of 50 CE species consisting of 55 regioisomers were identified in human plasma.Among them,two species were reported for the first time.Conclusion:This study is the most comprehensive identification of CE species in human plasma to date.These results will contribute to the in-depth profiling of CEs in human plasma and provide guidance for animal model selection when studying lipid-related diseases.
基金found by Guizhou Province Science and Technology Plan Project(No.Qiankeheji-ZK[2021]General 533)Domestic First-Class Discipline Construction Project in Guizhou Province(No.GNYL[2017]008)Guizhou Province Drug New Formulation New Process Technology Innovation Talent Team Project(No.Qiankehe Platform Talents[2017]5655).
文摘Background:Drying is a necessary component of traditional Chinese medicine extracts.The heating principle of microwave vacuum drying is different from that of the conventional heat method.However,at present,there is paucity of information on the drying process of traditional Chinese medicine extract by microwave vacuum drying,and the results of such process are unclear.Methods:To study the dynamic changes in the chemical characteristics of microwave vacuum drying under different drying conditions,ultrahigh-performance liquid chromatography fingerprint profiles were established using Radix isatidis extract as a model drug and analyzed using similarity analysis,partial least squares-discriminant analysis,and semi-quantitative analysis.In addition,a backpropagation artificial neural network model was developed to predict the moisture ratio of the drying process.Results:Qualitative results showed that the similarity between different drying conditions was greater than 0.95,and 2 amino acid components(peaks 5 and 6)affected by process fluctuations were screened out.The quantitative results showed that the mass concentration of component 1 fluctuated after drying,while that of component 2 increased.The optimal backpropagation artificial neural network model structure used to predict the moisture ratio was 5-4-1,with regression and mean squared error values of 0.996 and 0.0003,respectively,after training,which were well fitted and had a strong approximation ability.Conclusion:Upon comparison of fingerprints and the evaluation of statistical methods,common components of Radix isatidis extract had little variation under different drying conditions,and the selected components provided a reference for the establishment of process evaluation indexes.The establishment of backpropagation artificial neural network provides a theoretical basis for the application of microwave vacuum drying technology and online monitoring of moisture ratio.
基金The authors gratefully acknowledge the following support:National Key R&D Program(No.2018YFC0705400)National Natural Science Foundation of China(Grant No.51778223)+1 种基金Major Program of Science and Technology of Hunan Province(No.2017SK1010)The authors also express their sincere appreciation to the reviewers of this paper for their constructive comments and suggestions.
文摘In this study,a fully precast steel—ultrahigh performance concrete(UHPC)lightweight composite bridge(LWCB)was proposed based on Mapu Bridge,aiming at accelerating construction in bridge engineering.Cast-in-place joints are generally the controlling factor of segmental structures.Therefore,an innovative girder-to-girder joint that is suitable for LWCB was developed.A specimen consisting of two prefabricated steel—UHPC composite girder parts and one post-cast joint part was fabricated to determine if the joint can effectively transfer load between girders.The flexural behavior of the specimen under a negative bending moment was explored.Finite element analyses of Mapu Bridge showed that the nominal stress of critical sections could meet the required stress,indicating that the design is reasonable.The fatigue performance of the UHPC deck was assessed based on past research,and results revealed that the fatigue performance could meet the design requirements.Based on the test results,a crack width prediction method for the joint interface,a simplified calculation method for the design moment,and a deflection calculation method for the steel—UHPC composite girder in consideration of the UHPC tensile stiffness effect were presented.Good agreements were achieved between the predicted values and test results.
基金supported by the project‘Crosssectional study programmes innovation with respect to general knowledge courses at the Faculty of Forestry and Wood Technology,Mendel University in Brno,Registry No.CZ.1.07/2.2.00/28.0021 with the contribution of the EU funds and the state budget of the Czech Republic。
文摘A comprehensive experimental design was developed to determine suitable conditions(volume, percentage of solvent, extraction temperature) for the ethanol extraction of phenolic compounds from ten tropical woody plants. Wenge, angelim vermelho, zebrano, merbau,tigerwood, angelim pedra, jatoba, angelim amargoso,massaranduba, and doussie woods were used in experiments. The effects of three independent variables and their interactions on the yields of cinnamic and benzoic acid derivates were analyzed using UHPLC-PDA. The most significant parameters were found to be solvent percentage,extraction volume, and extraction temperature. Optimal conditions for the extraction of phenolic compound contents were an 80℃ extraction temperature, a 30 mL extraction volume, and the use of pure water as the extraction solvent. The tested species of woods contained mainly cinnamic acid derivates. Water extracts after hydrolysis contained greater amounts of cinnamic acid derivates than those extracts from non-hydrolyzed material.The total phenolics content was highest in water extracts of tigerwood, wenge and merbau;however, the extract of merbau wood was a stronger radical scavenger in ABTS?áassays: 34.11 ± 0.02 mM Trolox equivalents per g of dry extract. The main compounds possessing antioxidant activity in the extracts of vermelho wood assessed by UHPLC analysis were hydroxycinnamic acids.
文摘目的·研发一种具有高通量、高灵敏度和准确度的神经酰胺定量分析方法。方法·应用超高效液相色谱串联三重四极杆质谱(ultrahigh-performance liquid chromatography tandem triple-quadrupole mass spectrometry,UHPLC-MS)对14种神经酰胺进行定量分析,使用的色谱柱为ZORBAX Eclipse plus C8(2.1 mm×150 mm,1.8μm),流动相A为超纯水,流动相B为甲醇,流动相A和B中均加入2.5 mmol/L乙酸铵。采用多反应监测模式和正离子模式分析神经酰胺。结果·该方法能在10 min内定量分析14种神经酰胺,检测限(limit of detection,LOD)和定量限(limit of quantification,LOQ)分别为0.06~0.42 nmol/L和0.17~1.26 nmol/L。准确度范围为73.02%~122.39%,保留时间和积分面积的相对标准偏差分别为0.07%~0.54%和2.26%~13.98%。结论·基于UHPLC-MS技术的神经酰胺定量分析方法灵敏度高、重现性好、分析效率高,可用于检测细胞等生物样品中的神经酰胺含量。
