This study aims to quantify the effects of different pretreatment methods on the stable carbon isotope values of fatty acids in marine microalgae（Isochrysis zhanjiangenisis）.To identify the effects of sample prepara...This study aims to quantify the effects of different pretreatment methods on the stable carbon isotope values of fatty acids in marine microalgae（Isochrysis zhanjiangenisis）.To identify the effects of sample preparation on theδ^（13）C value and the fatty acid composition,we examined eight types of pretreatment methods including：（a） drying the sample followed by direct methyl esterification using HCl-CH3OH;（b） drying the sample followed by direct methyl esterification using H2SO4-CH3OH;（c） drying the sample by ultrasonic extraction and methylesterification using HCl-CH3OH;（d） drying the sample by ultrasonic extraction and methyl-esterification using H2SO4-CH3OH;（e） fresh sample followed by direct methyl-esterification using HCl-CH3OH;（f） fresh sample followed by direct methyl-esterification using H2SO4-CH3OH;（g） fresh sample with ultrasonic extraction followed by methyl-esterification using HCl-CH3OH,and（h） fresh sample with ultrasonic extraction followed by methylesterification using H2SO4-CH3 OH.The results show that the δ^（13）C values from Groups a-e,g and h fluctuated within 0.3‰,and the δ^（13）C values of Group f were approximately 0.7‰ lower than the other seven groups.Therefore,the different sample pretreatment methods used towards the extraction of fatty acids from marine microalgae may result in different results regarding the stable carbon isotope ratios,and if necessary a correction should be applied.展开更多
We prepared and characterized a form-stable composite phase change material （PCM） with higher thermal conductivity. Capric acid（CA）-myristic acid（MA） eutectic as core, poly-methyl methacrylate （PMMA） as suppor...We prepared and characterized a form-stable composite phase change material （PCM） with higher thermal conductivity. Capric acid（CA）-myristic acid（MA） eutectic as core, poly-methyl methacrylate （PMMA） as supportive matrix and modified graphite （MG） powders serving as the thermal conductance improver were blended by bulk- polymerization method. The composite PCMs with different MG mass fraction （2%, 5%, 7%, 10% and 15%） were characterized by FT-IR, SEM, DSC technique and mechanical tests. Thermal conductivities of the composites were measured by transient hot-wire method. The results indicate that MG powders have been successfully inserted into the CA-MA/PMMA matrix without any chemical reaction with each other. The MG/CA-MA/PMMA composites maintain good thermal storage performance while the thermal conductivity has been enhanced significantly. The composite PCM added with 15 wt% MG powders increases approximately as 195.9% in thermal conductivity. Moreover, the thermal conductivity improvement of the composite PCMs is also verified by the melting-freezing experiment, which is profitable for the heat transfer efficiency in latent heat thermal energy storage system.展开更多
Information on the dietary composition and food preferences of the giant jellyfish Nemopilema nomurai is important for understanding the trophic drivers of jellyfish outbreaks and their ecological consequences.We used...Information on the dietary composition and food preferences of the giant jellyfish Nemopilema nomurai is important for understanding the trophic drivers of jellyfish outbreaks and their ecological consequences.We used fatty acid(FA)and stable isotope(SI)biomarkers to analyze the diet of N.nomurai from the Yellow Sea in August 2016.N.nomurai was found at all sampling stations,with abundances ranging from 59 inds./km^(2) to 1651 inds./km^(2).There were no significant differences between large(>80 cm in diameter)and small(20–30 cm in diameter)medusae,either in FA compositions or in SI values,which suggests that large and small jellyfi sh have the same food composition and similar trophic levels.Compared to other zooplanktons,the relatively high levels of C20꞉4n-6 in total FAs(~12%)indicates that organic detritus contributes considerably to the food composition of the jellyfish.The mixed model Stable Isotope Analysis in R(SIAR)revealed that N.nomurai tended to prey on smaller organisms(<1000μm in diameter)which comprised about 70%of its diet.This means the N.nomurai blooms will put high feeding pressure on the small plankton.The similar SI values and FA composition indicates that krill may share the same food resources with N.nomurai,which suggests that the jellyfi sh blooms may affect krill populations as a result of food competition.展开更多
The lauric-myristic-palmitic acid( LA-MA-PA) ternary eutectic mixtures/expanded graphite( EG) composite phase change materials( PCMs) were prepared by absorbing LA-MA-PA into the porous network of EG. The optimum rati...The lauric-myristic-palmitic acid( LA-MA-PA) ternary eutectic mixtures/expanded graphite( EG) composite phase change materials( PCMs) were prepared by absorbing LA-MA-PA into the porous network of EG. The optimum ratio of ternary eutectic mixtures to EG was determined to be 93∶7 without liquid LA-MA-PA leakage from the composite PCMs. In order to make the structure more stable, the composite PCMs were encapsulated by surface treatment agent to prepare LA-MA-PA/EG encapsulating form-stable PCMs which were characterized by scanning electron microscope( SEM),Fourier transformation infrared spectroscope( FT-IR),differential scanning calorimetry( DSC) and thermal treatment. The results showed there was no chemical reaction between surface treatment agent and LA-MA-PA,and the samples were compactly encapsulated which left almost no imprint on the filter paper after thermal treatment. The phase change temperature and latent heat of LA-MA-PA/EG encapsulating form-stable PCMs were tested to be29. 32 ℃ and 96. 20 J/g,respectively. Additionally,the heat transfer efficiency of heat storage was improved by the addition of EG.展开更多
[Objective]The aim was to clarify the chemical substance basis of hypoglycemic and lipid-lowering effects of Pu-erh Tea. [Method]Pu-erh Tea was extracted with 95% ethanol,followed by petroleum ether,chloroform,ethyl a...[Objective]The aim was to clarify the chemical substance basis of hypoglycemic and lipid-lowering effects of Pu-erh Tea. [Method]Pu-erh Tea was extracted with 95% ethanol,followed by petroleum ether,chloroform,ethyl acetate and n-butanol extraction,after the further purification and through the NKA-9 macroporous resin and many times of Sephadex column chromatography,two compounds were isolated,in the same time,the effect of Uracil and Gallic acid on α-amylase was studied. [Result]The Uracil and Gallic acid were isolated and identified respectively from Pu-erh Tea and the Uracil was firstly isolated from Pu-erh Tea; Gallic acid had strong inhibition on α-amylase. [Conclusion]It could provide some theories on the hypoglycemic and lipid-lowering effects of Pu-erh Tea.展开更多
The objective of this study was to characterize the phaseolin type and a-amylase(αAI) level in common bean(Phaseolus vidgaris L.) accessions deposited in the Chinese National Genebank.The 40 accessions sampled were c...The objective of this study was to characterize the phaseolin type and a-amylase(αAI) level in common bean(Phaseolus vidgaris L.) accessions deposited in the Chinese National Genebank.The 40 accessions sampled were common varieties originating in Asia,North America,South America,Europe,and Africa.No Inca(I-) phaseolin was observed in the accessions.Only four accessions contained Tendergreen(T-) phaseolin and the remaining36 contained Sanilac(S-) phaseolin.aAI proteins extracted from nine accessions showed higher a-amylase inhibitory activity than the control(Phase 2,IC_(50) = 0.65 μg).These common bean accessions have potential use as nutraceutical ingredients.展开更多
Mercury （Hg） stable isotope analysis can provide new insight for understanding the biogeochemistry and sources of Hg in the polar regions. To completely extract the low contents of Hg in polar samples and to avoid i...Mercury （Hg） stable isotope analysis can provide new insight for understanding the biogeochemistry and sources of Hg in the polar regions. To completely extract the low contents of Hg in polar samples and to avoid isotopic fractionation during the sample preparation stage, an effective and reliable pretreatment method is needed. In this work, two different pretreatment methods were compared for measuring Hg stable isotopes in Antarctic moss samples. One method was acid digestion （HNO3 ： H2O2=5 ： 3, v/v） and the second was a combustion-trapping treatment with a trapping solution （HNO3：HCl=2：1, v/v）. There were no significant differences in the analytical results obtained with the two methods. The overall mean values and uncertainties of total Hg （THg） and the isotopic compositions of Hg in the referenced materials were all in good agreement with the certified and reported values, indicating that both methods were accurate and applicable. Acid digestion is highly efficient, while the combustion-trapping method can be used to treat samples with low Hg content. The proposed methods were successfully used to determine the Hg isotopic compositions in moss samples collected from the Antarctic.展开更多
There is an urgent need to elucidate the pathogenesis of myocardial ischemia(MI)and potential drug treatments.Here,the anti-MI mechanism and material basis of Ginkgo biloba L.extract(GBE)were studied from the perspect...There is an urgent need to elucidate the pathogenesis of myocardial ischemia(MI)and potential drug treatments.Here,the anti-MI mechanism and material basis of Ginkgo biloba L.extract(GBE)were studied from the perspective of energy metabolism flux regulation.Metabolic flux analysis(MFA)was performed to investigate energy metabolism flux disorder and the regulatory nodes of GBE components in isoproterenol(ISO)-induced ischemia-like cardiomyocytes.It showed that[U-13 C]glucose derived m+2 isotopologues from the upstream tricarboxylic acid(TCA)cycle metabolites were markedly accumulated in ISO-injured cardiomyocytes,but the opposite was seen for the downstream metabolites,while their total cellular concentrations were increased.This indicates a blockage of carbon flow from glycolysis and enhanced anaplerosis from other carbon sources.A Seahorse test was used to screen for GBE components with regulatory effects on mitochondrial aerobic respiratory dysfunction.It showed that bilobalide protected against impaired mitochondrial aerobic respiration.MFA also showed that bilobalide significantly modulated the TCA cycle flux,reduced abnormal metabolite accumulation,and balanced the demand of different carbon sources.Western blotting and PCR analysis showed that bilobalide decreased the enhanced expression of key metabolic enzymes in injured cells.Bilobalide’s efficacy was verified by in vivo experiments in rats.This is the first report to show that bilobalide,the active ingredient of GBE,protects against MI by rescuing impaired TCA cycle flux.This provides a new mechanism and potential drug treatment for MI.It also shows the potential of MFA/Seahorse combination as a powerful strategy for pharmacological research on herbal medicine.展开更多
The composition and compound-specific isotopes of fatty acids were studied within food webs in the East China Sea.Lipid-normalized stable carbon isotopes of total organic carbon had a good correlation with trophic lev...The composition and compound-specific isotopes of fatty acids were studied within food webs in the East China Sea.Lipid-normalized stable carbon isotopes of total organic carbon had a good correlation with trophic level.Variations in fatty acid compositions among different species were observed but were unclear.Different dietary structures could be traced from molecular isotopes of selected fatty acids in the Shiba shrimp(Matapenaeus joyneri),the coastal mud shrimp(Solenocera crassicomis) and the northern Maoxia shrimp(Acetes chinensis).Both M.joyneri and S.crassicomis are mainly benthos feeders,while A.chinensis is a pelagic species,although they have a similar fatty acid composition.There was a good correlation for isotopes of arachidonic acid(C20:4n6;ARA) and docosahexaenoic acid(C22:6n3;DHA)among pelagic species from higher trophic levels.The isotopic compositions of DHA in benthic species were more negative than those of pelagic species at the same trophic level.The fact that the diet of benthic species contains more degraded items,the carbon isotopes of which are derived from a large biochemical fraction,may be the reason for this variation.A comparative study of benthic and pelagic species demonstrated the different carbon sources in potential food items and the presence of a more complex system at the watersediment interface.展开更多
In order to improve the thermal storage capacity of expanded vermiculite（EV） based formstable composite PCM（FS-PCM） via organic modification of EV, first, EV was modified with a sodium stearate（Na St） as surface...In order to improve the thermal storage capacity of expanded vermiculite（EV） based formstable composite PCM（FS-PCM） via organic modification of EV, first, EV was modified with a sodium stearate（Na St） as surface modifier, and organic EV（OEV） with hydrophobicity and higher adsorption capacity for fatty acid was obtained. A novel capric-stearic acid eutectic（CA-SA）/OEV FS-PCM with high thermal storage capacity was then developed. OEV and CA-SA/OEV were characterized by scanning electron microscopy（SEM）, X-ray diffraction（XRD）, Fourier transform infrared spectroscopy（FTIR）, differential scanning calorimetry（DSC）, thermal gravimetry（TG）, and thermal cycling test. Results showed that OEV has obvious hydrophobicity and a higher adsorption capacity for fatty acid. Its adsorption ratio has increased by 48.71% compared with that of EV. CA-SA/OEV possesses high thermal storage density（112.52 J/g）, suitable melting temperature（20.49 ℃）, good chemical compatibility, excellent thermal stability and reliability, indicating great application potential for building energy efficiency. Moreover, organic modification of inorganic matrix may offer novel options for improving its adsorption capacity for organic PCMs and increasing heat storage capacity of corresponding FS-PCMs.展开更多
The design of highly active and stable RuO_(2)-based nanostructures for acidic oxygen evolution reaction(OER)is extremely important for the development of water electrolysis technology,yet remains great challenges.We ...The design of highly active and stable RuO_(2)-based nanostructures for acidic oxygen evolution reaction(OER)is extremely important for the development of water electrolysis technology,yet remains great challenges.We here demonstrate that the incorporation of S into RuCuO nanorings(NRs)can significantly enhance the acidic OER performance.Experimental investigations show that the incorporation of S can optimize the interaction of Ru and O,and therefore significantly suppresses the dissolution of Ru in acidic condition.The optimized catalyst(SH-RuCuO NRs)displays superior OER performance to the commercial RuO_(2)/C.Impressively,the SH-RuCuO NRs can exhibit significantly enhanced stability for 3,000 cycles of cyclic voltammetry test and more than 250 h chronopotentiometry test at 10 mA·cm^(-2)in 0.5 M H_(2)SO_(4).This work highlights a potential strategy for designing active and stable RuO_(2)-based electrocatalysts for acidic OER.展开更多
Direct infusion mass spectrometry(DIMS) is a powerful technique in clinical diagnosis for screening neonatal amino acid metabolic disorders from dried blood spots(DBS).However,DIMS sometimes generated false-positive r...Direct infusion mass spectrometry(DIMS) is a powerful technique in clinical diagnosis for screening neonatal amino acid metabolic disorders from dried blood spots(DBS).However,DIMS sometimes generated false-positive results for analysis of amino acids.In this work,we utilized a stable isotope derivatization method,combining with liquid chromatography tandem mass spectrometry(SID-LC-MS),to improve the specificity for screening amino acids in DBS specimens.A pair of isotope reagents,p-(dimethylamino)phenyl isothiocyanate(DMAP-NCS) and 4-isothiocyanato-N,N-bis(methyl-[2H2])aniline([2H4]DMAP-NCS),was synthesized and used to label amino acids in DBS specimens.The [2H4]DMAP-NCS labelled amino acid standards were used as internal standards to compensate the matrix effect.This method was validated by measuring linearity,recovery and accuracy.The results showed that the developed SID-LC-MS method can be used for sensitive and selective determination of 12 diagnostically important amino acids in DBS specimens.展开更多
基金The State Oceanic Public Welfare Project of China under contract Nos 2012418012-02 and 201305002
文摘This study aims to quantify the effects of different pretreatment methods on the stable carbon isotope values of fatty acids in marine microalgae（Isochrysis zhanjiangenisis）.To identify the effects of sample preparation on theδ^（13）C value and the fatty acid composition,we examined eight types of pretreatment methods including：（a） drying the sample followed by direct methyl esterification using HCl-CH3OH;（b） drying the sample followed by direct methyl esterification using H2SO4-CH3OH;（c） drying the sample by ultrasonic extraction and methylesterification using HCl-CH3OH;（d） drying the sample by ultrasonic extraction and methyl-esterification using H2SO4-CH3OH;（e） fresh sample followed by direct methyl-esterification using HCl-CH3OH;（f） fresh sample followed by direct methyl-esterification using H2SO4-CH3OH;（g） fresh sample with ultrasonic extraction followed by methyl-esterification using HCl-CH3OH,and（h） fresh sample with ultrasonic extraction followed by methylesterification using H2SO4-CH3 OH.The results show that the δ^（13）C values from Groups a-e,g and h fluctuated within 0.3‰,and the δ^（13）C values of Group f were approximately 0.7‰ lower than the other seven groups.Therefore,the different sample pretreatment methods used towards the extraction of fatty acids from marine microalgae may result in different results regarding the stable carbon isotope ratios,and if necessary a correction should be applied.
基金Founded by the National Mega-Project of Scientific&Technical Supporting Programs during the 11th Five-year Period(No.2006BAJ04A04)the Foundation of Liaoning EducationalCommittee(No.L2012225)
文摘We prepared and characterized a form-stable composite phase change material （PCM） with higher thermal conductivity. Capric acid（CA）-myristic acid（MA） eutectic as core, poly-methyl methacrylate （PMMA） as supportive matrix and modified graphite （MG） powders serving as the thermal conductance improver were blended by bulk- polymerization method. The composite PCMs with different MG mass fraction （2%, 5%, 7%, 10% and 15%） were characterized by FT-IR, SEM, DSC technique and mechanical tests. Thermal conductivities of the composites were measured by transient hot-wire method. The results indicate that MG powders have been successfully inserted into the CA-MA/PMMA matrix without any chemical reaction with each other. The MG/CA-MA/PMMA composites maintain good thermal storage performance while the thermal conductivity has been enhanced significantly. The composite PCM added with 15 wt% MG powders increases approximately as 195.9% in thermal conductivity. Moreover, the thermal conductivity improvement of the composite PCMs is also verified by the melting-freezing experiment, which is profitable for the heat transfer efficiency in latent heat thermal energy storage system.
基金Supported by the National Key Research and Development Program of China(Nos.2017YFC1404401,2017YFC1404402)the National Natural Science Foundation of China(No.41706189)。
文摘Information on the dietary composition and food preferences of the giant jellyfish Nemopilema nomurai is important for understanding the trophic drivers of jellyfish outbreaks and their ecological consequences.We used fatty acid(FA)and stable isotope(SI)biomarkers to analyze the diet of N.nomurai from the Yellow Sea in August 2016.N.nomurai was found at all sampling stations,with abundances ranging from 59 inds./km^(2) to 1651 inds./km^(2).There were no significant differences between large(>80 cm in diameter)and small(20–30 cm in diameter)medusae,either in FA compositions or in SI values,which suggests that large and small jellyfi sh have the same food composition and similar trophic levels.Compared to other zooplanktons,the relatively high levels of C20꞉4n-6 in total FAs(~12%)indicates that organic detritus contributes considerably to the food composition of the jellyfish.The mixed model Stable Isotope Analysis in R(SIAR)revealed that N.nomurai tended to prey on smaller organisms(<1000μm in diameter)which comprised about 70%of its diet.This means the N.nomurai blooms will put high feeding pressure on the small plankton.The similar SI values and FA composition indicates that krill may share the same food resources with N.nomurai,which suggests that the jellyfi sh blooms may affect krill populations as a result of food competition.
基金National Science&Technology Pillar Program during the Twelfth Five-Year Plan Period,China(No.2014BAL03B04)
文摘The lauric-myristic-palmitic acid( LA-MA-PA) ternary eutectic mixtures/expanded graphite( EG) composite phase change materials( PCMs) were prepared by absorbing LA-MA-PA into the porous network of EG. The optimum ratio of ternary eutectic mixtures to EG was determined to be 93∶7 without liquid LA-MA-PA leakage from the composite PCMs. In order to make the structure more stable, the composite PCMs were encapsulated by surface treatment agent to prepare LA-MA-PA/EG encapsulating form-stable PCMs which were characterized by scanning electron microscope( SEM),Fourier transformation infrared spectroscope( FT-IR),differential scanning calorimetry( DSC) and thermal treatment. The results showed there was no chemical reaction between surface treatment agent and LA-MA-PA,and the samples were compactly encapsulated which left almost no imprint on the filter paper after thermal treatment. The phase change temperature and latent heat of LA-MA-PA/EG encapsulating form-stable PCMs were tested to be29. 32 ℃ and 96. 20 J/g,respectively. Additionally,the heat transfer efficiency of heat storage was improved by the addition of EG.
基金Supported by National Science and Technology Support Project(2007BAD58B04 )Special Fund Project of Modern Agriculture(Tea) Industrial Technology SystemYunnan Department of Education and Scientific Research Fund (07Y40163)~~
文摘[Objective]The aim was to clarify the chemical substance basis of hypoglycemic and lipid-lowering effects of Pu-erh Tea. [Method]Pu-erh Tea was extracted with 95% ethanol,followed by petroleum ether,chloroform,ethyl acetate and n-butanol extraction,after the further purification and through the NKA-9 macroporous resin and many times of Sephadex column chromatography,two compounds were isolated,in the same time,the effect of Uracil and Gallic acid on α-amylase was studied. [Result]The Uracil and Gallic acid were isolated and identified respectively from Pu-erh Tea and the Uracil was firstly isolated from Pu-erh Tea; Gallic acid had strong inhibition on α-amylase. [Conclusion]It could provide some theories on the hypoglycemic and lipid-lowering effects of Pu-erh Tea.
基金supported by the Program of Science and Technology Cooperation with Hong Kong, Macao, and Taiwan, China (2013DFH30050)the special fund for Agro-scientific Research in the Public Interest (201403063)+1 种基金the earmarked fund for China Agriculture Research System (CYTX-014)Agricultural Science and Technology Innovation Program
文摘The objective of this study was to characterize the phaseolin type and a-amylase(αAI) level in common bean(Phaseolus vidgaris L.) accessions deposited in the Chinese National Genebank.The 40 accessions sampled were common varieties originating in Asia,North America,South America,Europe,and Africa.No Inca(I-) phaseolin was observed in the accessions.Only four accessions contained Tendergreen(T-) phaseolin and the remaining36 contained Sanilac(S-) phaseolin.aAI proteins extracted from nine accessions showed higher a-amylase inhibitory activity than the control(Phase 2,IC_(50) = 0.65 μg).These common bean accessions have potential use as nutraceutical ingredients.
基金supported by the National Natural Science Foundation of China (Grant nos.41422306 and 41673118)the National Basic Research Program of China (Grant no.2013CB430004)
文摘Mercury （Hg） stable isotope analysis can provide new insight for understanding the biogeochemistry and sources of Hg in the polar regions. To completely extract the low contents of Hg in polar samples and to avoid isotopic fractionation during the sample preparation stage, an effective and reliable pretreatment method is needed. In this work, two different pretreatment methods were compared for measuring Hg stable isotopes in Antarctic moss samples. One method was acid digestion （HNO3 ： H2O2=5 ： 3, v/v） and the second was a combustion-trapping treatment with a trapping solution （HNO3：HCl=2：1, v/v）. There were no significant differences in the analytical results obtained with the two methods. The overall mean values and uncertainties of total Hg （THg） and the isotopic compositions of Hg in the referenced materials were all in good agreement with the certified and reported values, indicating that both methods were accurate and applicable. Acid digestion is highly efficient, while the combustion-trapping method can be used to treat samples with low Hg content. The proposed methods were successfully used to determine the Hg isotopic compositions in moss samples collected from the Antarctic.
基金supported by grants from the National Natural Science Foundation of China(Grant No.:81803496)the CAMS Innovation Fund for Medical Sciences(Grant No.:2016-I2M-3-016)the Applications and Core Technology University Research(ACT-UR,Grant No.:4084)。
文摘There is an urgent need to elucidate the pathogenesis of myocardial ischemia(MI)and potential drug treatments.Here,the anti-MI mechanism and material basis of Ginkgo biloba L.extract(GBE)were studied from the perspective of energy metabolism flux regulation.Metabolic flux analysis(MFA)was performed to investigate energy metabolism flux disorder and the regulatory nodes of GBE components in isoproterenol(ISO)-induced ischemia-like cardiomyocytes.It showed that[U-13 C]glucose derived m+2 isotopologues from the upstream tricarboxylic acid(TCA)cycle metabolites were markedly accumulated in ISO-injured cardiomyocytes,but the opposite was seen for the downstream metabolites,while their total cellular concentrations were increased.This indicates a blockage of carbon flow from glycolysis and enhanced anaplerosis from other carbon sources.A Seahorse test was used to screen for GBE components with regulatory effects on mitochondrial aerobic respiratory dysfunction.It showed that bilobalide protected against impaired mitochondrial aerobic respiration.MFA also showed that bilobalide significantly modulated the TCA cycle flux,reduced abnormal metabolite accumulation,and balanced the demand of different carbon sources.Western blotting and PCR analysis showed that bilobalide decreased the enhanced expression of key metabolic enzymes in injured cells.Bilobalide’s efficacy was verified by in vivo experiments in rats.This is the first report to show that bilobalide,the active ingredient of GBE,protects against MI by rescuing impaired TCA cycle flux.This provides a new mechanism and potential drug treatment for MI.It also shows the potential of MFA/Seahorse combination as a powerful strategy for pharmacological research on herbal medicine.
基金Supported by the National Basic Research Program of China(973 Program)(Nos.2011CB409801,2014CB441502)
文摘The composition and compound-specific isotopes of fatty acids were studied within food webs in the East China Sea.Lipid-normalized stable carbon isotopes of total organic carbon had a good correlation with trophic level.Variations in fatty acid compositions among different species were observed but were unclear.Different dietary structures could be traced from molecular isotopes of selected fatty acids in the Shiba shrimp(Matapenaeus joyneri),the coastal mud shrimp(Solenocera crassicomis) and the northern Maoxia shrimp(Acetes chinensis).Both M.joyneri and S.crassicomis are mainly benthos feeders,while A.chinensis is a pelagic species,although they have a similar fatty acid composition.There was a good correlation for isotopes of arachidonic acid(C20:4n6;ARA) and docosahexaenoic acid(C22:6n3;DHA)among pelagic species from higher trophic levels.The isotopic compositions of DHA in benthic species were more negative than those of pelagic species at the same trophic level.The fact that the diet of benthic species contains more degraded items,the carbon isotopes of which are derived from a large biochemical fraction,may be the reason for this variation.A comparative study of benthic and pelagic species demonstrated the different carbon sources in potential food items and the presence of a more complex system at the watersediment interface.
基金Funded by the Major State Research Development Program of China during the 13th Five-Year Plan Period(No.2016YFC0700904)the Science and Technology Support Program of Hubei Province(Nos.2014BAA134 and 2015BAA107)
文摘In order to improve the thermal storage capacity of expanded vermiculite（EV） based formstable composite PCM（FS-PCM） via organic modification of EV, first, EV was modified with a sodium stearate（Na St） as surface modifier, and organic EV（OEV） with hydrophobicity and higher adsorption capacity for fatty acid was obtained. A novel capric-stearic acid eutectic（CA-SA）/OEV FS-PCM with high thermal storage capacity was then developed. OEV and CA-SA/OEV were characterized by scanning electron microscopy（SEM）, X-ray diffraction（XRD）, Fourier transform infrared spectroscopy（FTIR）, differential scanning calorimetry（DSC）, thermal gravimetry（TG）, and thermal cycling test. Results showed that OEV has obvious hydrophobicity and a higher adsorption capacity for fatty acid. Its adsorption ratio has increased by 48.71% compared with that of EV. CA-SA/OEV possesses high thermal storage density（112.52 J/g）, suitable melting temperature（20.49 ℃）, good chemical compatibility, excellent thermal stability and reliability, indicating great application potential for building energy efficiency. Moreover, organic modification of inorganic matrix may offer novel options for improving its adsorption capacity for organic PCMs and increasing heat storage capacity of corresponding FS-PCMs.
基金This work was financially supported by the National Key R&D Program of China(Nos.2017YFA0208200 and 2016YFA0204100)the National Natural Science Foundation of China(Nos.22025108 and 51802206)+2 种基金Guangdong Provincial Natural Science Fund for Distinguished Young Scholars(No.2021B1515020081)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)and the start-up supports from Xiamen University and the Guangzhou Key Laboratory of Low Dimensional Materials and Energy Storage Devices(No.20195010002).
文摘The design of highly active and stable RuO_(2)-based nanostructures for acidic oxygen evolution reaction(OER)is extremely important for the development of water electrolysis technology,yet remains great challenges.We here demonstrate that the incorporation of S into RuCuO nanorings(NRs)can significantly enhance the acidic OER performance.Experimental investigations show that the incorporation of S can optimize the interaction of Ru and O,and therefore significantly suppresses the dissolution of Ru in acidic condition.The optimized catalyst(SH-RuCuO NRs)displays superior OER performance to the commercial RuO_(2)/C.Impressively,the SH-RuCuO NRs can exhibit significantly enhanced stability for 3,000 cycles of cyclic voltammetry test and more than 250 h chronopotentiometry test at 10 mA·cm^(-2)in 0.5 M H_(2)SO_(4).This work highlights a potential strategy for designing active and stable RuO_(2)-based electrocatalysts for acidic OER.
基金supported by the National Key R&D Program of China(No.2018YFA0900400)the National Natural ScienceFoundation of China(Nos.21635006,31670373,21721005,21904099)the Postdoctoral Science Foundation of China(No.2018M642893)。
文摘Direct infusion mass spectrometry(DIMS) is a powerful technique in clinical diagnosis for screening neonatal amino acid metabolic disorders from dried blood spots(DBS).However,DIMS sometimes generated false-positive results for analysis of amino acids.In this work,we utilized a stable isotope derivatization method,combining with liquid chromatography tandem mass spectrometry(SID-LC-MS),to improve the specificity for screening amino acids in DBS specimens.A pair of isotope reagents,p-(dimethylamino)phenyl isothiocyanate(DMAP-NCS) and 4-isothiocyanato-N,N-bis(methyl-[2H2])aniline([2H4]DMAP-NCS),was synthesized and used to label amino acids in DBS specimens.The [2H4]DMAP-NCS labelled amino acid standards were used as internal standards to compensate the matrix effect.This method was validated by measuring linearity,recovery and accuracy.The results showed that the developed SID-LC-MS method can be used for sensitive and selective determination of 12 diagnostically important amino acids in DBS specimens.
