The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/M...The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/MS). PGC was applied to study the F t curve of the multiblock copolymer and PGC/MS was used to separate and identify the pyrolyzates. DTA experiment was used to study the decomposition temperature. The results show that the beginning point of elastomer’s decomposition was about 300?℃ and the decomposition temperature of most of the sample was 550?℃. Many pyrolyzates were produced because of the breaking of weak bonds in the sample. The possible microstructure was verified and the pyrolysis pathway of the copolymer was investigated.展开更多
AIM To study the role of microbial metabolites in the modulation of biochemical and physiological processes in irritable bowel syndrome(IBS).METHODS In the current study, using a metabolomic approach, we analyzed the ...AIM To study the role of microbial metabolites in the modulation of biochemical and physiological processes in irritable bowel syndrome(IBS).METHODS In the current study, using a metabolomic approach, we analyzed the key metabolites differentially excreted in the feces of control mice and mice with IBS, with or without Clostridium butyricum(C. butyricum) treatment. C57 BL/6 mice were divided into control, IBS, and IBS + C. butyricum groups. In the IBS and IBS + C. butyricum groups, the mice were subjected to water avoidance stress(WAS) for 1 h/d for ten days. Gas chromatography/mass spectrometry(GC-MS) together with multivariate analysis was employed to compare the fecal samples between groups. RESULTS WAS exposure established an appropriate model of IBS in mice, with symptoms of visceral hyperalgesia and diarrhea. The differences in the metabolite profiles between the control group and IBS group significantly changed with the progression of IBS(days 0, 5, 10, and 17). A total of 14 differentially excreted metabolites were identified between the control and IBS groups, and phenylethylamine was a major metabolite induced by stress. In addition, phenylalanine metabolism was found to be the most relevant metabolic pathway. Between the IBS group and IBS + C. butyricum group, 10 differentially excreted metabolites were identified. Among these, pantothenate and coenzyme A(Co A) biosynthesis metabolites, as well as steroid hormone biosynthesis metabolites were identified as significantly relevant metabolic pathways.CONCLUSION The metabolic profile of IBS mice is significantly altered compared to control mice. Supplementation with C. butyricum to IBS mice may provide a considerable benefit by modulating host metabolism.展开更多
Mitochondria regulate numerous crucial cell processes, including energy production, apoptotic cell death, oxidative stress, calcium homeostasis and lipid metabolism. Here, we applied an efficient mitochondria-based ce...Mitochondria regulate numerous crucial cell processes, including energy production, apoptotic cell death, oxidative stress, calcium homeostasis and lipid metabolism. Here, we applied an efficient mitochondria-based centrifugal ultrafiltration/liquid chromatography/mass spectrometry（LC/MS） method,also known as screening method for mitochondria-targeted bioactive constituents（SM-MBC）. This method allowed searching natural mitochondria-targeting compounds from traditional Chinese medicines（TCMs）, including Puerariae Radix（PR） and Chuanxiong Radix（CR）. A total of 23 active compounds were successfully discovered from the two TCMs extracts. Among these 23 hit compounds, 17 were identified by LC/MS, 12 of which were novel mitochondria-targeting compounds. Among these, 6 active compounds were analyzed in vitro for pharmacological tests and found able to affect mitochondrial functions. We also investigated the effects of the hit compounds on Hep G2 cell proliferation and on loss of cardiomyocyte viability induced by hypoxia/reoxygenation injury. The results obtained are useful for in-depth understanding of mechanisms underlying TCMs therapeutic effects at mitochondria level and for developing novel potential drugs using TCMs as lead compounds. Finally, we showed that SM-MBC was an efficient protocol for the rapid screening of mitochondria-targeting constituents from complex samples such as PR and CR extracts.展开更多
A novel metabolomic method based on gas chromatography/mass spectrometry （GC-MS） was applied to determine the metabolites in the serum of piglets in response to weaning and dietary L-glutamine （Gin） supplementatio...A novel metabolomic method based on gas chromatography/mass spectrometry （GC-MS） was applied to determine the metabolites in the serum of piglets in response to weaning and dietary L-glutamine （Gin） supplementation. Thirty-six 21-d-old piglets were randomly assigned into three groups. One group continued to suckle from the sows （suckling group）, whereas the other two groups were weaned and their diets were supplemented with 1% （w/w） Gin or isonitrogenous L-alanine, respectively, representing Gin group or control group. Serum samples were collected to characterize metabolites after a 7-d treatment. Results showed that twenty metabolites were down-regulated significantly （P〈0.05） in control piglets compared with suckling ones. These data demonstrated that early weaning causes a wide range of metabolic changes across arginine and proline metabolism, aminosugar and nucleotide metabolism, galactose metabolism, glycerophospholipid metabolism, biosynthesis of unsaturated fatty acid, and fatty acid metabolism. Dietary Gin supplementation increased the levels of creatinine, D-xylose, 2-hydroxybutyric acid, palmitelaidic acid, and a-L-galactofuranose （P〈0.05） in eady weaned piglets, and were involved in the arginine and proline metabolism, carbohydrate metabolism, and fatty acid metabolism. A leave-one-out cross-validation of random forest analysis indicated that creatinine was the most important metabolite among the three groups. Notably, the concentration of creatinine in control piglets was decreased （P=0.00001） compared to the suckling piglets, and increased （P=0.0003） in Gin-supplemented piglets. A correlation network for weaned and suckling piglets revealed that early weaning changed the metabolic pathways, leading to the abnormality of carbohydrate metabolism, amino acid metabolism, and lipid metabolism, which could be partially improved by dietary Gin supplementation. These findings provide fresh insight into the complex metabolic changes in response to early weaning and dietary Gin supplementation in piglets.展开更多
Quality control of ginseng currently is mainly based on ginsenoside analysis,but rarely focuses on the volatile organic components.In the current work,an untargeted metabolomics approach,by headspace solid-phase micro...Quality control of ginseng currently is mainly based on ginsenoside analysis,but rarely focuses on the volatile organic components.In the current work,an untargeted metabolomics approach,by headspace solid-phase micro-extraction gas chromatography/mass spectrometry(HS-SPME-GC/MS),was elaborated and further employed to holistically compare the compositional difference of the volatile components simultaneously from 12 Panax herbal medicines,which included P.ginseng(PG),P.quinquefolius(PQ),P.notoginseng(PN),red ginseng(PGR),P.ginseng leaf(PGL),P.quinquefolius leaf(PQL),P.notoginseng leaf(PNL),P.ginseng flower(PGF),P.quinquefolius flower(PQF),P.notoginseng flower(PNF),P.japonicus(PJ),and P.japonicus var.major(PJvm).Chromatographic separation was performed on an HP-5MS elastic quartz capillary column using helium as the carrier gas,enabling good resolution within 1 h.We were able to characterize totally 259 volatile compounds,including 82 terpenes(T),46 alcohols(Alc),29 ketones(K),25 aldehydes(Ald),21 esters(E),and the others.By analyzing 90 batches of ginseng samples based on the untargeted metabolomics workflows,236 differential ions were unveiled,and accordingly 36 differential volatile components were discovered.It is the first report that simultaneously compares the compositional difference of volatile components among 12 Panax herbal medicines,and useful information is provided for the quality control of ginseng aside from the well-known ginsenosides.展开更多
Keto-enol tautomers of curcumin were confirmed by reversed-phase liquid chromatography（RPLC）/ hybrid quadrupole ion trap/time-of-flight mass spectrometry（QIT/TOFMS）.Tautomers gave different MS/MS spectra in negati...Keto-enol tautomers of curcumin were confirmed by reversed-phase liquid chromatography（RPLC）/ hybrid quadrupole ion trap/time-of-flight mass spectrometry（QIT/TOFMS）.Tautomers gave different MS/MS spectra in negative mode.Different mass spectra were also obtained by hydrogen/deuterium exchange LC/MS/MS in positive mode.Our results suggest that enol form is the major form in the solution（water/acetonitrile）.展开更多
In present work,the volatile constituents of Curcuma longa L.,A.lancea (Thunb.) DC.,Foeniculum vulgare Mill,and Cinnamomun cassia Presl.have been analyzed by flash distillation/capillary gas chro-matography/mass spect...In present work,the volatile constituents of Curcuma longa L.,A.lancea (Thunb.) DC.,Foeniculum vulgare Mill,and Cinnamomun cassia Presl.have been analyzed by flash distillation/capillary gas chro-matography/mass spectrometry.The results are consistent with those obtained by conventional steam distillation extraction method.The optimum condition of flash distillation has been studied.The experimental results showed that this new technique proved to be a simple,rapid and efficient tool for microanalysis of volatile constituents of Chinese medicinal herbs.展开更多
RNA modification has recently been proposed to play important roles in biological regulation. The detection and quantification of RNA modifications generally are challenging tasks since most of the modifications exist...RNA modification has recently been proposed to play important roles in biological regulation. The detection and quantification of RNA modifications generally are challenging tasks since most of the modifications exist in low abundance in vivo. Here we developed an on-line trapping/capillary hydrophilic-interaction liquid chromatography/electrospray ionization-mass spectrometry(on-line trapping/cHILIC/MS) method for sensitive and simultaneous quantification of RNA modifications of N^6-methyladenosine(m^6A) and 5-methylcytosine(5-mC) from human blood. The hydrophilic organic-silica hybrid monolith was prepared using sol-gel combined with "thiol-ene" click reaction for the separation of nucleosides. A poly(MAA-co-EGDMA) monolithic capillary was used as the on-line trapping column.With the developed on-line trapping/cHILIC/MS analytical platform, the detection limits of m^6A and 5-mC can reach to 0.06 fmol and 0.10 fmol. We then investigated the contents of m^6A and 5-mC in human blood RNA from healthy persons at the age of 6-14 and 60-68 years. Our results showed that both m^6A and 5-mC contents were significantly decreased in elder persons, suggesting the RNA modifications of m^6A and 5-mC are correlated to aging.展开更多
Some natural products, such as traditional Chinese medicines（TCMs）, contain compounds with anticancer activity and have attracted a great interest in recent years as alternative anticancer therapies. A quick and con...Some natural products, such as traditional Chinese medicines（TCMs）, contain compounds with anticancer activity and have attracted a great interest in recent years as alternative anticancer therapies. A quick and convenient assay for screening antimicrotubule compounds in which in vitro microdialysis/high-performance liquid chromatography （HPLC） is used to monitor the binding of the compounds extracted from TCM Taxus cuspidata Siebold ＆ Zucc（Taxus） to microtubules is reported. It was observed that the extract of Taxus contains at least five compounds which have affinity interaction with microtubules by biological fingerprinting analysis, and they were identified as the taxoids of taxol, baccatin III, 10-deacetylbaccatin Ⅲ（10-DAB）, cephalomannine and 7-epi-10-deacetyltaxol （7-epi-10-DAT） based on the comparison of their high-performance liquid chromatographic/mass spectrometric and UV spectra with those of the standard samples, both assembly-promoting and disassembly-inhibiting characteristics of those compounds were evaluated. It was observed that baccatin Ⅲ and 10-DAB bound to microtubules and the binding degrees were influenced by GTP. Competitive binding behavior of taxol with other four taxoids to microtubules was also investigated.展开更多
Liquid chromatography/mass spectrometry (LC/MS) is now considered to be the most promising analytical method for the determination of biological substances, especially nonvolatile or highly polar substances However, s...Liquid chromatography/mass spectrometry (LC/MS) is now considered to be the most promising analytical method for the determination of biological substances, especially nonvolatile or highly polar substances However, some compounds do not show enough sensitivity in LC/MS and soft ionization methods commonly used in LC/MS, such as electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI), sometimes do not give satisfactory structural information This report presents an overview of the derivatization methods in the LC/MS analysis of neurosteroids or neuroactive neurosteroids, which are synthesized and accumulated in the nervous system The derivatization of pregnenolone 3 sulfate, one of these steroids, with 4 ( N,N dimethylaminosulfonyl) 7 hydrazino 2,1,3 benzoxadiazole gave a satisfactory sensitivity during the quantitative analysis using LC/ESI MS The obtained results are much lower than those previously obtained using gas chromatography/mass spectrometry or radioimmunoassay On the other hand, the derivatization to acetate was useful for the treatment of labile catechol estrogens in rat brains and gave enough structural information in LC/APCI MS, which confirmed the existence of catechol estrogens in mammalian展开更多
Detecting microplastics(MPs)under 20μm has been challenging,yet these tiny particles may pose significant threats to human health and the environment.They can be inhaled or ingested,potentially leading to respiratory...Detecting microplastics(MPs)under 20μm has been challenging,yet these tiny particles may pose significant threats to human health and the environment.They can be inhaled or ingested,potentially leading to respiratory diseases and gastrointestinal problems.This research proposed confocal laser scanning microscopy(CLSM)for identifying MPs smaller than 20μm and to support its validity by comparing results to a typical gravimetric analysis for these small MPs in road dust samples using pyrolysis-gas chromatography/mass spectrometry(Pyr-GC/MS).A total of 30 road dust samples were collected from urban areas in Seoul and 15 samples from rural regions throughout South Korea.A strong agreement was observed between the results obtained from CLSM and Pyr-GC/MS,confirming the effectiveness of both methods in measuring MPs under 20μm especially when polyolefins are dominating MPs.CLSM,coupled with BiofilmQ software,enabled precise volumetric analysis,while Pyr-GC/MS provided rapid identification of chemical compositions,suggesting that they are complementary.Mass concentrations of MPs in rural road dust(14.2±6.4μg g^(−1))were greater than those in urban road dust(7.8±4.6μg g^(−1)),likely due to less stringent plastic waste management and increased agricultural plastic use in rural areas.This study builds upon prior volumetric imaging methods by enabling mass quantification of MPs under 20μm using CLSM and validating the results against Pyr-GC/MS in realworld road dust samples.展开更多
Arsenic speciation in freshwater fish is crucial for providing meaningful consumption guidelines that allow the public to make informed decisions regarding its consumption.While marine fish have attractedmuch research...Arsenic speciation in freshwater fish is crucial for providing meaningful consumption guidelines that allow the public to make informed decisions regarding its consumption.While marine fish have attractedmuch research interest due to their higher arsenic content,research on freshwater fish is limited due to the challenges in quantifying and identifying arsenic species present at trace levels.We describe here a sensitivemethod and its application to the quantification of arsenic species in freshwater fish.Arsenic species from fish tissues were extracted using a methanol/water mixture(1:1 vol.ratio)and ultrasound sonication.Anion-exchange high-performance liquid chromatography(HPLC)enabled separation of arsenobetaine(AsB),inorganic arsenite(iAs^(Ⅲ)),dimethylarsinic acid(DMA),monomethylarsonic acid(MMA),inorganic arsenate(iAs^(Ⅴ)),and three new arsenic species.Inductively coupled plasma mass spectrometry(ICPMS)provided highly sensitive and specific detection of arsenic.A limit of detection of 0.25μg/kg(wet weight fish tissue)was achieved for the five target arsenic species:AsB,iAs^(Ⅲ),DMA,MMA,and iAs^(Ⅴ).A series of experimentswere conducted to ensure the accuracy and validity of the analytical method.The method was successfully applied to the determination of arsenic species in lakewhitefish,northern pike,and walleye,with AsB,DMA,and iAs^(Ⅴ) being frequently detected.Three new arsenic species were detected,but their chromatographic retention times did not match with those of any available arsenic standards.Future research is necessary to elucidate the identity of these new arsenic species detected in freshwater fish.展开更多
Background:Polygonum multiflorum-induced liver injury(PM-DILI)has significantly hindered its clinical application and development.Methods:This study investigates the variation in content and toxicity of dian-thrones,t...Background:Polygonum multiflorum-induced liver injury(PM-DILI)has significantly hindered its clinical application and development.Methods:This study investigates the variation in content and toxicity of dian-thrones,the toxic components of P.multiflorum,during different processing cycles.We employed the ultra-high-performance liquid chromatography triple quadrupole mass spectrometry method to quantify six dianthrones in raw P.multiflorum and formulations processed with a method called nine cycles of steaming and sunning.Additionally,toxicity assessments were conducted using human normal liver cell line L02 and zebrafish embryos.Results:Results indicate a gradual reduction in dianthrones content with increasing processing cycles.Processed formulations exhibited significantly reduced cytotoxic-ity in L02 cells and hepatotoxicity in zebrafish embryos.Conclusions:Our findings elucidate the relationship between processing cycles and P.multiflorum toxicity,providing theoretical support for its safe use.展开更多
[Objectives]This study was conducted to establish a detection method for the simultaneous determination of 18 perfluorinated compounds(PFCs)in milk tea by ultra-high performance liquid chromatography-tandem mass spect...[Objectives]This study was conducted to establish a detection method for the simultaneous determination of 18 perfluorinated compounds(PFCs)in milk tea by ultra-high performance liquid chromatography-tandem mass spectrometry(UHPLC-MS/MS).[Methods]The samples were first subjected to precipitation of proteins by potassium ferrocyanide solution and zinc acetate solution,and then extracted by acetonitrile and detected by LC-MS/MS.Next,sodium chloride was added,and after vortex centrifugation,the acetonitrile layer was dried by blowing with nitrogen.Subsequently,1 ml of methanol was added to prepare a test solution.An ACQUITY UPLC BEH C18(2.6 m,2.1 mm×100 mm)chromatographic column was used for liquid phase separation,and gradient elution was performed using 10 mmol ammonium acetate solution-acetonitrile as the mobile phase.The MS detection adopted the MRM mode for acquisition,positive and negative ion mode switching for simultaneous determination,and external standard method for quantification.[Results]In the linear ranges of the target substances,the correlation coefficients R^(2)were all greater than 0.99.The detection limits of the method was in the range of 0.001-0.05μg/kg,and the quantitation limits were in the range of 0.03-0.20 ng/L.The recovery values ranged from 72.8%to 110.5%.[Conclusions]This method has high sensitivity and good accuracy,and thus strong practical value.展开更多
Objective:Lanqin oral liquid(LOL),as a traditional Chinese medicine prescription,has obvious clinical efficacy in the treatment of pharyngeal inflammation.Exploring the distribution of LOL prototype components and met...Objective:Lanqin oral liquid(LOL),as a traditional Chinese medicine prescription,has obvious clinical efficacy in the treatment of pharyngeal inflammation.Exploring the distribution of LOL prototype components and metabolites in plasma is of great significance for understanding potentially effective compounds.The aim of this study is to elucidate the metabolites and main metabolic pathways of LQL in vivo.Methods:In this study,a reliable approach integrated background subtraction and mass defect filtering(MDF),based on quadrupole time-of-flight mass spectrometry(QTOF-MS)technology,was performed to systematically scan the metabolites of LOL in rat plasma.In addition,according to the prototype mass spectrometry fragmentation pattern and combined with metabolic pathway analysis,a biotransformation oriented analysis strategy was established and applied to the identification of metabolites in LOL in vivo.Results:As a result,159 compounds(58 prototypes and 101 metabolites)were identified or tentatively characterized in drug-containing plasma,including 74 flavonoids,30 alkaloids,34 terpenoids,five phenylpropanoids,six phenolic acids,five fatty acids,and five other type components.The main metabolic pathways include methylation,demethylation,hydroxylation,hydrogenation,glucuronidation,and sulfation.Conclusions:This study provides an overall characterization of the metabolites of LOL in vivo for the first time,providing a solid material basis for exploring the therapeutic effects and pharmacological mechanisms of LOL.展开更多
This study established a method using gas chromatography-electrostatic field Orbitrap high-resolution mass spectrometry(Orbitrap GC-MS)for the simultaneous determination of 70 organic pollutants across 4 categories:or...This study established a method using gas chromatography-electrostatic field Orbitrap high-resolution mass spectrometry(Orbitrap GC-MS)for the simultaneous determination of 70 organic pollutants across 4 categories:organochlorine pesticides(OCPs),polycyclic aromatic hydrocarbons(PAHs),polychlorinated biphenyls(PCBs),and phthalates(PAEs)in infant cereal-based supplementary foods.Techniques integrating cryogenic centrifugation and lipid and protein adsorbent(LPAS)purification were employed.The precise mass numbers of target compounds were determined by Orbitrap GC-MS in full-scan mode(Full MS),which effectively minimized matrix interferences in these foods.Method validation on rice flour samples demonstrated that the 70 compounds exhibited excellent linearity within their respective mass concentration ranges,with correlation coefficients all exceeding 0.995.The detection limits for this method ranged 0.10–1.00μg/kg,while the quantification limits varied 0.3–3.0μg/kg,meeting the established detection requirements.The average spike recovery of the 70 compounds at 3 spiked levels(5,20,and 100μg/kg)ranged 75.3%–119.3%,with relative standard deviations ranging 1.8%–10.8%.Both inter-day and intra-day precision demonstrated relative standard deviation values below 15%.This method was applied to analyze 100 samples of commercial infant cereal-based supplementary food,revealing the presence of PAEs and PAHs in 12.0%of the samples.Notably,no OCPs or PCBs were detected.The detected concentrations of benzo[a]pyrene(Ba P)and dibutyl phthalate(DBP)were(4.2±0.1)and(1.8±0.3)μg/kg,respectively.This method is straightforward,highly sensitive,and suitable for the rapid screening and confirmation of 70 organic pollutants in infant cereal-based supplementary foods.展开更多
[Objectives]To extract and purify perfluoroalkyl and polyfluoroalkyl substances(PFAS)from aquatic products and determine the optimal pretreatment conditions.[Methods]The QuEChERS method was employed for the extraction...[Objectives]To extract and purify perfluoroalkyl and polyfluoroalkyl substances(PFAS)from aquatic products and determine the optimal pretreatment conditions.[Methods]The QuEChERS method was employed for the extraction and purification of PFAS in aquatic products.The detection of PFAS was carried out using liquid chromatography-tandem mass spectrometry(LC-MS/MS)in ESI negative ion mode with multiple reaction monitoring(MRM),and quantification was performed using the external standard method.By optimizing instrument parameters such as ion source temperature,spray voltage,and collision energy,high selectivity and sensitivity of the detection were ensured.[Results]The established calibration curves for 28 PFAS compounds compounds,covering a range of 0.02 to 20 ng/mL,demonstrated excellent linearity.Spike recovery tests yielded limits of detection(LOD)between 0.02 and 0.5μg/kg for the 28 PFAS compounds compounds,with recovery rates ranging from 72.2%to 113.0%.[Conclusions]The method established in this study demonstrates excellent linearity,and is accurate,reliable,efficient,simple,and rapid.It possesses considerable practical applicability and can be used for the quality and risk assessment of 28 PFAS compounds compounds in aquatic products,indicating high practical utility.展开更多
Objective Previous studies link lower body mass index(BMI)with increased obsessive-compulsive disorder(OCD)risk,yet other body mass indicators may be more etioloically relevant.We dissected the causal association betw...Objective Previous studies link lower body mass index(BMI)with increased obsessive-compulsive disorder(OCD)risk,yet other body mass indicators may be more etioloically relevant.We dissected the causal association between body fat mass(FM)and OCD.Methods Summary statistics from genome-wide association studies of European ancestry were utilized to conduct two-sample Mendelian randomization analysis.Heterogeneity,horizontal pleiotropy,and sensitivity analyses were performed to assess the robustness.Results The inverse variance weighting method demonstrated that a genetically predicted decrease in FM was causally associated with an increased OCD risk[odds ratio(OR)=0.680,95%confidence interval(CI):0.528–0.875,P=0.003].Similar estimates were obtained using the weighted median approach(OR=0.633,95%CI:0.438–0.915,P=0.015).Each standard deviation increases in genetically predicted body fat percentage corresponded to a reduced OCD risk(OR=0.638,95%CI:0.455–0.896,P=0.009).The sensitivity analysis confirmed the robustness of these findings with no outlier instrument variables identified.Conclusion The negative causal association between FM and the risk of OCD suggests that the prevention or treatment of mental disorders should include not only the control of BMI but also fat distribution and body composition.展开更多
Although traditional gamma-gamma density(GGD)logging technology is widely utilized,its potential environmental risks have prompted the development of more environmentally friendly neutron-gamma density(NGD)logging tec...Although traditional gamma-gamma density(GGD)logging technology is widely utilized,its potential environmental risks have prompted the development of more environmentally friendly neutron-gamma density(NGD)logging technology.However,NGD measurements are influenced by both neutron and gamma radiations.In the logging environment,variations in the formation composition indicate different elemental compositions,which affect the neutron-gamma reaction cross-sections and gamma generation.Compared to traditional gamma sources such as Cs-137,these changes significantly affect the generation and transport of neutron-induced inelastic gamma rays and hinder accurate measurements.To address this,a novel method is proposed that incorporates the mass attenuation coefficient function to account for the effects of various lithologies and pore contents on gamma-ray attenuation,thereby achieving more accurate density measurements by clarifying the transport processes of inelastic gamma rays with varying energies and spatial distributions in varied logging environments.The proposed method avoids the complex correction of neutron transport and is verified through Monte Carlo simulations for its applicability across various lithologies and pore contents,demonstrating absolute density errors that are less than 0.02 g/cm^(3)in clean formations and indicating good accuracy.This study clarifies the NGD mechanism and provides theoretical guidance for the application of NGD logging methods.Further studies will be conducted on extreme environmental conditions and tool calibration.展开更多
Pulsed dynamic electrolysis(PDE),driven by renewable energy,has emerged as an innovative electrocatalytic conversion method,demonstrating significant potential in addressing global energy challenges and promoting sust...Pulsed dynamic electrolysis(PDE),driven by renewable energy,has emerged as an innovative electrocatalytic conversion method,demonstrating significant potential in addressing global energy challenges and promoting sustainable development.Despite significant progress in various electrochemical systems,the regulatory mechanisms of PDE in energy and mass transfer and the lifespan extension of electrolysis systems,particularly in water electrolysis(WE)for hydrogen production,remain insufficiently explored.Therefore,there is an urgent need for a deeper understanding of the unique contributions of PDE in mass transfer enhancement,microenvironment regulation,and hydrogen production optimization,aiming to achieve low-energy consumption,high catalytic activity,and long-term stability in the generation of target products.Here,this review critically examines the microenvironmental effects of PDE on energy and mass transfer,the electrode degradation mechanisms in the lifespan extension of electrolysis systems,and the key factors in enhancing WE for hydrogen production,providing a comprehensive summary of current research progress.The review focuses on the complex regulatory mechanisms of frequency,duty cycle,amplitude,and other factors in hydrogen evolution reaction(HER)performance within PDE strategies,revealing the interrelationships among them.Finally,the potential future directions and challenges for transitioning from laboratory studies to industrial applications are proposed.展开更多
文摘The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/MS). PGC was applied to study the F t curve of the multiblock copolymer and PGC/MS was used to separate and identify the pyrolyzates. DTA experiment was used to study the decomposition temperature. The results show that the beginning point of elastomer’s decomposition was about 300?℃ and the decomposition temperature of most of the sample was 550?℃. Many pyrolyzates were produced because of the breaking of weak bonds in the sample. The possible microstructure was verified and the pyrolysis pathway of the copolymer was investigated.
基金Supported by the National Natural Science Foundation of China,No.81470814 and No.81400594Zhejiang Provincial Natural Science Foundation of China,No.LQ14H160014
文摘AIM To study the role of microbial metabolites in the modulation of biochemical and physiological processes in irritable bowel syndrome(IBS).METHODS In the current study, using a metabolomic approach, we analyzed the key metabolites differentially excreted in the feces of control mice and mice with IBS, with or without Clostridium butyricum(C. butyricum) treatment. C57 BL/6 mice were divided into control, IBS, and IBS + C. butyricum groups. In the IBS and IBS + C. butyricum groups, the mice were subjected to water avoidance stress(WAS) for 1 h/d for ten days. Gas chromatography/mass spectrometry(GC-MS) together with multivariate analysis was employed to compare the fecal samples between groups. RESULTS WAS exposure established an appropriate model of IBS in mice, with symptoms of visceral hyperalgesia and diarrhea. The differences in the metabolite profiles between the control group and IBS group significantly changed with the progression of IBS(days 0, 5, 10, and 17). A total of 14 differentially excreted metabolites were identified between the control and IBS groups, and phenylethylamine was a major metabolite induced by stress. In addition, phenylalanine metabolism was found to be the most relevant metabolic pathway. Between the IBS group and IBS + C. butyricum group, 10 differentially excreted metabolites were identified. Among these, pantothenate and coenzyme A(Co A) biosynthesis metabolites, as well as steroid hormone biosynthesis metabolites were identified as significantly relevant metabolic pathways.CONCLUSION The metabolic profile of IBS mice is significantly altered compared to control mice. Supplementation with C. butyricum to IBS mice may provide a considerable benefit by modulating host metabolism.
基金Financial support from the National Natural Science Foundation of China (Grant 81660596, 81673395 and 81373921)the Research Fund for the Doctoral Program of Higher Education of China (Grant 20130001110057)the Application and Basis Research Project of Yunnan China (Grant 2017FF117-(013) and 2016FD050)
文摘Mitochondria regulate numerous crucial cell processes, including energy production, apoptotic cell death, oxidative stress, calcium homeostasis and lipid metabolism. Here, we applied an efficient mitochondria-based centrifugal ultrafiltration/liquid chromatography/mass spectrometry（LC/MS） method,also known as screening method for mitochondria-targeted bioactive constituents（SM-MBC）. This method allowed searching natural mitochondria-targeting compounds from traditional Chinese medicines（TCMs）, including Puerariae Radix（PR） and Chuanxiong Radix（CR）. A total of 23 active compounds were successfully discovered from the two TCMs extracts. Among these 23 hit compounds, 17 were identified by LC/MS, 12 of which were novel mitochondria-targeting compounds. Among these, 6 active compounds were analyzed in vitro for pharmacological tests and found able to affect mitochondrial functions. We also investigated the effects of the hit compounds on Hep G2 cell proliferation and on loss of cardiomyocyte viability induced by hypoxia/reoxygenation injury. The results obtained are useful for in-depth understanding of mechanisms underlying TCMs therapeutic effects at mitochondria level and for developing novel potential drugs using TCMs as lead compounds. Finally, we showed that SM-MBC was an efficient protocol for the rapid screening of mitochondria-targeting constituents from complex samples such as PR and CR extracts.
基金Project supported by the National Natural Science Foundation of China(No.30700578)the Local Cooperative Enterprises of Zhejiang Province,China(Nos.H20080692 and H20020883)
文摘A novel metabolomic method based on gas chromatography/mass spectrometry （GC-MS） was applied to determine the metabolites in the serum of piglets in response to weaning and dietary L-glutamine （Gin） supplementation. Thirty-six 21-d-old piglets were randomly assigned into three groups. One group continued to suckle from the sows （suckling group）, whereas the other two groups were weaned and their diets were supplemented with 1% （w/w） Gin or isonitrogenous L-alanine, respectively, representing Gin group or control group. Serum samples were collected to characterize metabolites after a 7-d treatment. Results showed that twenty metabolites were down-regulated significantly （P〈0.05） in control piglets compared with suckling ones. These data demonstrated that early weaning causes a wide range of metabolic changes across arginine and proline metabolism, aminosugar and nucleotide metabolism, galactose metabolism, glycerophospholipid metabolism, biosynthesis of unsaturated fatty acid, and fatty acid metabolism. Dietary Gin supplementation increased the levels of creatinine, D-xylose, 2-hydroxybutyric acid, palmitelaidic acid, and a-L-galactofuranose （P〈0.05） in eady weaned piglets, and were involved in the arginine and proline metabolism, carbohydrate metabolism, and fatty acid metabolism. A leave-one-out cross-validation of random forest analysis indicated that creatinine was the most important metabolite among the three groups. Notably, the concentration of creatinine in control piglets was decreased （P=0.00001） compared to the suckling piglets, and increased （P=0.0003） in Gin-supplemented piglets. A correlation network for weaned and suckling piglets revealed that early weaning changed the metabolic pathways, leading to the abnormality of carbohydrate metabolism, amino acid metabolism, and lipid metabolism, which could be partially improved by dietary Gin supplementation. These findings provide fresh insight into the complex metabolic changes in response to early weaning and dietary Gin supplementation in piglets.
基金National Natural Science Foundation of China(Grant No.81872996)Natural Science Foundation of Tianjin of China(Grant No.20JCYBJC00060).
文摘Quality control of ginseng currently is mainly based on ginsenoside analysis,but rarely focuses on the volatile organic components.In the current work,an untargeted metabolomics approach,by headspace solid-phase micro-extraction gas chromatography/mass spectrometry(HS-SPME-GC/MS),was elaborated and further employed to holistically compare the compositional difference of the volatile components simultaneously from 12 Panax herbal medicines,which included P.ginseng(PG),P.quinquefolius(PQ),P.notoginseng(PN),red ginseng(PGR),P.ginseng leaf(PGL),P.quinquefolius leaf(PQL),P.notoginseng leaf(PNL),P.ginseng flower(PGF),P.quinquefolius flower(PQF),P.notoginseng flower(PNF),P.japonicus(PJ),and P.japonicus var.major(PJvm).Chromatographic separation was performed on an HP-5MS elastic quartz capillary column using helium as the carrier gas,enabling good resolution within 1 h.We were able to characterize totally 259 volatile compounds,including 82 terpenes(T),46 alcohols(Alc),29 ketones(K),25 aldehydes(Ald),21 esters(E),and the others.By analyzing 90 batches of ginseng samples based on the untargeted metabolomics workflows,236 differential ions were unveiled,and accordingly 36 differential volatile components were discovered.It is the first report that simultaneously compares the compositional difference of volatile components among 12 Panax herbal medicines,and useful information is provided for the quality control of ginseng aside from the well-known ginsenosides.
基金supported by the Research Fund for the Doctoral Program of Higher Education(No.20110002110052)
文摘Keto-enol tautomers of curcumin were confirmed by reversed-phase liquid chromatography（RPLC）/ hybrid quadrupole ion trap/time-of-flight mass spectrometry（QIT/TOFMS）.Tautomers gave different MS/MS spectra in negative mode.Different mass spectra were also obtained by hydrogen/deuterium exchange LC/MS/MS in positive mode.Our results suggest that enol form is the major form in the solution（water/acetonitrile）.
文摘In present work,the volatile constituents of Curcuma longa L.,A.lancea (Thunb.) DC.,Foeniculum vulgare Mill,and Cinnamomun cassia Presl.have been analyzed by flash distillation/capillary gas chro-matography/mass spectrometry.The results are consistent with those obtained by conventional steam distillation extraction method.The optimum condition of flash distillation has been studied.The experimental results showed that this new technique proved to be a simple,rapid and efficient tool for microanalysis of volatile constituents of Chinese medicinal herbs.
基金financially supported by the National Natural Science Foundation of China (Nos. 21522507, 21672166, 21728802, 21721005)
文摘RNA modification has recently been proposed to play important roles in biological regulation. The detection and quantification of RNA modifications generally are challenging tasks since most of the modifications exist in low abundance in vivo. Here we developed an on-line trapping/capillary hydrophilic-interaction liquid chromatography/electrospray ionization-mass spectrometry(on-line trapping/cHILIC/MS) method for sensitive and simultaneous quantification of RNA modifications of N^6-methyladenosine(m^6A) and 5-methylcytosine(5-mC) from human blood. The hydrophilic organic-silica hybrid monolith was prepared using sol-gel combined with "thiol-ene" click reaction for the separation of nucleosides. A poly(MAA-co-EGDMA) monolithic capillary was used as the on-line trapping column.With the developed on-line trapping/cHILIC/MS analytical platform, the detection limits of m^6A and 5-mC can reach to 0.06 fmol and 0.10 fmol. We then investigated the contents of m^6A and 5-mC in human blood RNA from healthy persons at the age of 6-14 and 60-68 years. Our results showed that both m^6A and 5-mC contents were significantly decreased in elder persons, suggesting the RNA modifications of m^6A and 5-mC are correlated to aging.
基金the National Natural Science Foundation of China(No.90709021)Knowledge Innovation Program of Chi-nese Academy of Sciences(No.KJCX2.YW.HO9)
文摘Some natural products, such as traditional Chinese medicines（TCMs）, contain compounds with anticancer activity and have attracted a great interest in recent years as alternative anticancer therapies. A quick and convenient assay for screening antimicrotubule compounds in which in vitro microdialysis/high-performance liquid chromatography （HPLC） is used to monitor the binding of the compounds extracted from TCM Taxus cuspidata Siebold ＆ Zucc（Taxus） to microtubules is reported. It was observed that the extract of Taxus contains at least five compounds which have affinity interaction with microtubules by biological fingerprinting analysis, and they were identified as the taxoids of taxol, baccatin III, 10-deacetylbaccatin Ⅲ（10-DAB）, cephalomannine and 7-epi-10-deacetyltaxol （7-epi-10-DAT） based on the comparison of their high-performance liquid chromatographic/mass spectrometric and UV spectra with those of the standard samples, both assembly-promoting and disassembly-inhibiting characteristics of those compounds were evaluated. It was observed that baccatin Ⅲ and 10-DAB bound to microtubules and the binding degrees were influenced by GTP. Competitive binding behavior of taxol with other four taxoids to microtubules was also investigated.
文摘Liquid chromatography/mass spectrometry (LC/MS) is now considered to be the most promising analytical method for the determination of biological substances, especially nonvolatile or highly polar substances However, some compounds do not show enough sensitivity in LC/MS and soft ionization methods commonly used in LC/MS, such as electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI), sometimes do not give satisfactory structural information This report presents an overview of the derivatization methods in the LC/MS analysis of neurosteroids or neuroactive neurosteroids, which are synthesized and accumulated in the nervous system The derivatization of pregnenolone 3 sulfate, one of these steroids, with 4 ( N,N dimethylaminosulfonyl) 7 hydrazino 2,1,3 benzoxadiazole gave a satisfactory sensitivity during the quantitative analysis using LC/ESI MS The obtained results are much lower than those previously obtained using gas chromatography/mass spectrometry or radioimmunoassay On the other hand, the derivatization to acetate was useful for the treatment of labile catechol estrogens in rat brains and gave enough structural information in LC/APCI MS, which confirmed the existence of catechol estrogens in mammalian
基金supported by a National Research Foundation of Korea(NRF)grant funded by the Korean Government(Ministry of Science and ICT)(No.RS-2023-00209242).
文摘Detecting microplastics(MPs)under 20μm has been challenging,yet these tiny particles may pose significant threats to human health and the environment.They can be inhaled or ingested,potentially leading to respiratory diseases and gastrointestinal problems.This research proposed confocal laser scanning microscopy(CLSM)for identifying MPs smaller than 20μm and to support its validity by comparing results to a typical gravimetric analysis for these small MPs in road dust samples using pyrolysis-gas chromatography/mass spectrometry(Pyr-GC/MS).A total of 30 road dust samples were collected from urban areas in Seoul and 15 samples from rural regions throughout South Korea.A strong agreement was observed between the results obtained from CLSM and Pyr-GC/MS,confirming the effectiveness of both methods in measuring MPs under 20μm especially when polyolefins are dominating MPs.CLSM,coupled with BiofilmQ software,enabled precise volumetric analysis,while Pyr-GC/MS provided rapid identification of chemical compositions,suggesting that they are complementary.Mass concentrations of MPs in rural road dust(14.2±6.4μg g^(−1))were greater than those in urban road dust(7.8±4.6μg g^(−1)),likely due to less stringent plastic waste management and increased agricultural plastic use in rural areas.This study builds upon prior volumetric imaging methods by enabling mass quantification of MPs under 20μm using CLSM and validating the results against Pyr-GC/MS in realworld road dust samples.
基金supported by Alberta Health,Alberta Innovates,the Canada Research Chairs Program,the Canadian Institutes of Health Research,and the Natural Sciences and Engineering Research Council of Canada。
文摘Arsenic speciation in freshwater fish is crucial for providing meaningful consumption guidelines that allow the public to make informed decisions regarding its consumption.While marine fish have attractedmuch research interest due to their higher arsenic content,research on freshwater fish is limited due to the challenges in quantifying and identifying arsenic species present at trace levels.We describe here a sensitivemethod and its application to the quantification of arsenic species in freshwater fish.Arsenic species from fish tissues were extracted using a methanol/water mixture(1:1 vol.ratio)and ultrasound sonication.Anion-exchange high-performance liquid chromatography(HPLC)enabled separation of arsenobetaine(AsB),inorganic arsenite(iAs^(Ⅲ)),dimethylarsinic acid(DMA),monomethylarsonic acid(MMA),inorganic arsenate(iAs^(Ⅴ)),and three new arsenic species.Inductively coupled plasma mass spectrometry(ICPMS)provided highly sensitive and specific detection of arsenic.A limit of detection of 0.25μg/kg(wet weight fish tissue)was achieved for the five target arsenic species:AsB,iAs^(Ⅲ),DMA,MMA,and iAs^(Ⅴ).A series of experimentswere conducted to ensure the accuracy and validity of the analytical method.The method was successfully applied to the determination of arsenic species in lakewhitefish,northern pike,and walleye,with AsB,DMA,and iAs^(Ⅴ) being frequently detected.Three new arsenic species were detected,but their chromatographic retention times did not match with those of any available arsenic standards.Future research is necessary to elucidate the identity of these new arsenic species detected in freshwater fish.
基金National Natural Science Foundation of China,Grant/Award Number:81973476Chinese Society of Toxicology,Grant/Award Number:CST2021CT101。
文摘Background:Polygonum multiflorum-induced liver injury(PM-DILI)has significantly hindered its clinical application and development.Methods:This study investigates the variation in content and toxicity of dian-thrones,the toxic components of P.multiflorum,during different processing cycles.We employed the ultra-high-performance liquid chromatography triple quadrupole mass spectrometry method to quantify six dianthrones in raw P.multiflorum and formulations processed with a method called nine cycles of steaming and sunning.Additionally,toxicity assessments were conducted using human normal liver cell line L02 and zebrafish embryos.Results:Results indicate a gradual reduction in dianthrones content with increasing processing cycles.Processed formulations exhibited significantly reduced cytotoxic-ity in L02 cells and hepatotoxicity in zebrafish embryos.Conclusions:Our findings elucidate the relationship between processing cycles and P.multiflorum toxicity,providing theoretical support for its safe use.
基金Supported by Natural Science Foundation of Hunan Province(2024JJ8266).
文摘[Objectives]This study was conducted to establish a detection method for the simultaneous determination of 18 perfluorinated compounds(PFCs)in milk tea by ultra-high performance liquid chromatography-tandem mass spectrometry(UHPLC-MS/MS).[Methods]The samples were first subjected to precipitation of proteins by potassium ferrocyanide solution and zinc acetate solution,and then extracted by acetonitrile and detected by LC-MS/MS.Next,sodium chloride was added,and after vortex centrifugation,the acetonitrile layer was dried by blowing with nitrogen.Subsequently,1 ml of methanol was added to prepare a test solution.An ACQUITY UPLC BEH C18(2.6 m,2.1 mm×100 mm)chromatographic column was used for liquid phase separation,and gradient elution was performed using 10 mmol ammonium acetate solution-acetonitrile as the mobile phase.The MS detection adopted the MRM mode for acquisition,positive and negative ion mode switching for simultaneous determination,and external standard method for quantification.[Results]In the linear ranges of the target substances,the correlation coefficients R^(2)were all greater than 0.99.The detection limits of the method was in the range of 0.001-0.05μg/kg,and the quantitation limits were in the range of 0.03-0.20 ng/L.The recovery values ranged from 72.8%to 110.5%.[Conclusions]This method has high sensitivity and good accuracy,and thus strong practical value.
文摘Objective:Lanqin oral liquid(LOL),as a traditional Chinese medicine prescription,has obvious clinical efficacy in the treatment of pharyngeal inflammation.Exploring the distribution of LOL prototype components and metabolites in plasma is of great significance for understanding potentially effective compounds.The aim of this study is to elucidate the metabolites and main metabolic pathways of LQL in vivo.Methods:In this study,a reliable approach integrated background subtraction and mass defect filtering(MDF),based on quadrupole time-of-flight mass spectrometry(QTOF-MS)technology,was performed to systematically scan the metabolites of LOL in rat plasma.In addition,according to the prototype mass spectrometry fragmentation pattern and combined with metabolic pathway analysis,a biotransformation oriented analysis strategy was established and applied to the identification of metabolites in LOL in vivo.Results:As a result,159 compounds(58 prototypes and 101 metabolites)were identified or tentatively characterized in drug-containing plasma,including 74 flavonoids,30 alkaloids,34 terpenoids,five phenylpropanoids,six phenolic acids,five fatty acids,and five other type components.The main metabolic pathways include methylation,demethylation,hydroxylation,hydrogenation,glucuronidation,and sulfation.Conclusions:This study provides an overall characterization of the metabolites of LOL in vivo for the first time,providing a solid material basis for exploring the therapeutic effects and pharmacological mechanisms of LOL.
基金funded by National Key Research and Development Program for Young Scientists of China(2022YFF1102900)Hebei Province High-level Talent Funding Project(C20221009)。
文摘This study established a method using gas chromatography-electrostatic field Orbitrap high-resolution mass spectrometry(Orbitrap GC-MS)for the simultaneous determination of 70 organic pollutants across 4 categories:organochlorine pesticides(OCPs),polycyclic aromatic hydrocarbons(PAHs),polychlorinated biphenyls(PCBs),and phthalates(PAEs)in infant cereal-based supplementary foods.Techniques integrating cryogenic centrifugation and lipid and protein adsorbent(LPAS)purification were employed.The precise mass numbers of target compounds were determined by Orbitrap GC-MS in full-scan mode(Full MS),which effectively minimized matrix interferences in these foods.Method validation on rice flour samples demonstrated that the 70 compounds exhibited excellent linearity within their respective mass concentration ranges,with correlation coefficients all exceeding 0.995.The detection limits for this method ranged 0.10–1.00μg/kg,while the quantification limits varied 0.3–3.0μg/kg,meeting the established detection requirements.The average spike recovery of the 70 compounds at 3 spiked levels(5,20,and 100μg/kg)ranged 75.3%–119.3%,with relative standard deviations ranging 1.8%–10.8%.Both inter-day and intra-day precision demonstrated relative standard deviation values below 15%.This method was applied to analyze 100 samples of commercial infant cereal-based supplementary food,revealing the presence of PAEs and PAHs in 12.0%of the samples.Notably,no OCPs or PCBs were detected.The detected concentrations of benzo[a]pyrene(Ba P)and dibutyl phthalate(DBP)were(4.2±0.1)and(1.8±0.3)μg/kg,respectively.This method is straightforward,highly sensitive,and suitable for the rapid screening and confirmation of 70 organic pollutants in infant cereal-based supplementary foods.
文摘[Objectives]To extract and purify perfluoroalkyl and polyfluoroalkyl substances(PFAS)from aquatic products and determine the optimal pretreatment conditions.[Methods]The QuEChERS method was employed for the extraction and purification of PFAS in aquatic products.The detection of PFAS was carried out using liquid chromatography-tandem mass spectrometry(LC-MS/MS)in ESI negative ion mode with multiple reaction monitoring(MRM),and quantification was performed using the external standard method.By optimizing instrument parameters such as ion source temperature,spray voltage,and collision energy,high selectivity and sensitivity of the detection were ensured.[Results]The established calibration curves for 28 PFAS compounds compounds,covering a range of 0.02 to 20 ng/mL,demonstrated excellent linearity.Spike recovery tests yielded limits of detection(LOD)between 0.02 and 0.5μg/kg for the 28 PFAS compounds compounds,with recovery rates ranging from 72.2%to 113.0%.[Conclusions]The method established in this study demonstrates excellent linearity,and is accurate,reliable,efficient,simple,and rapid.It possesses considerable practical applicability and can be used for the quality and risk assessment of 28 PFAS compounds compounds in aquatic products,indicating high practical utility.
基金supported by the Yanzhao Gold Talent Project of Hebei Province(NO.HJZD202506)。
文摘Objective Previous studies link lower body mass index(BMI)with increased obsessive-compulsive disorder(OCD)risk,yet other body mass indicators may be more etioloically relevant.We dissected the causal association between body fat mass(FM)and OCD.Methods Summary statistics from genome-wide association studies of European ancestry were utilized to conduct two-sample Mendelian randomization analysis.Heterogeneity,horizontal pleiotropy,and sensitivity analyses were performed to assess the robustness.Results The inverse variance weighting method demonstrated that a genetically predicted decrease in FM was causally associated with an increased OCD risk[odds ratio(OR)=0.680,95%confidence interval(CI):0.528–0.875,P=0.003].Similar estimates were obtained using the weighted median approach(OR=0.633,95%CI:0.438–0.915,P=0.015).Each standard deviation increases in genetically predicted body fat percentage corresponded to a reduced OCD risk(OR=0.638,95%CI:0.455–0.896,P=0.009).The sensitivity analysis confirmed the robustness of these findings with no outlier instrument variables identified.Conclusion The negative causal association between FM and the risk of OCD suggests that the prevention or treatment of mental disorders should include not only the control of BMI but also fat distribution and body composition.
基金supported by the National Natural Science Foundation of China(U23B20151 and 52171253).
文摘Although traditional gamma-gamma density(GGD)logging technology is widely utilized,its potential environmental risks have prompted the development of more environmentally friendly neutron-gamma density(NGD)logging technology.However,NGD measurements are influenced by both neutron and gamma radiations.In the logging environment,variations in the formation composition indicate different elemental compositions,which affect the neutron-gamma reaction cross-sections and gamma generation.Compared to traditional gamma sources such as Cs-137,these changes significantly affect the generation and transport of neutron-induced inelastic gamma rays and hinder accurate measurements.To address this,a novel method is proposed that incorporates the mass attenuation coefficient function to account for the effects of various lithologies and pore contents on gamma-ray attenuation,thereby achieving more accurate density measurements by clarifying the transport processes of inelastic gamma rays with varying energies and spatial distributions in varied logging environments.The proposed method avoids the complex correction of neutron transport and is verified through Monte Carlo simulations for its applicability across various lithologies and pore contents,demonstrating absolute density errors that are less than 0.02 g/cm^(3)in clean formations and indicating good accuracy.This study clarifies the NGD mechanism and provides theoretical guidance for the application of NGD logging methods.Further studies will be conducted on extreme environmental conditions and tool calibration.
基金financially supported by the Key Research and Development Program of Heilongjiang Province(No.2024ZXJ03C06)National Natural Science Foundation of China(No.52476192,No.52106237)+1 种基金Natural Science Foundation of Heilongjiang Province(No.YQ2022E027)Technology Project of China Datang Technology Innovation Co.,Ltd(No.DTKC-2024-20610).
文摘Pulsed dynamic electrolysis(PDE),driven by renewable energy,has emerged as an innovative electrocatalytic conversion method,demonstrating significant potential in addressing global energy challenges and promoting sustainable development.Despite significant progress in various electrochemical systems,the regulatory mechanisms of PDE in energy and mass transfer and the lifespan extension of electrolysis systems,particularly in water electrolysis(WE)for hydrogen production,remain insufficiently explored.Therefore,there is an urgent need for a deeper understanding of the unique contributions of PDE in mass transfer enhancement,microenvironment regulation,and hydrogen production optimization,aiming to achieve low-energy consumption,high catalytic activity,and long-term stability in the generation of target products.Here,this review critically examines the microenvironmental effects of PDE on energy and mass transfer,the electrode degradation mechanisms in the lifespan extension of electrolysis systems,and the key factors in enhancing WE for hydrogen production,providing a comprehensive summary of current research progress.The review focuses on the complex regulatory mechanisms of frequency,duty cycle,amplitude,and other factors in hydrogen evolution reaction(HER)performance within PDE strategies,revealing the interrelationships among them.Finally,the potential future directions and challenges for transitioning from laboratory studies to industrial applications are proposed.
