An evaporation/condensation flow cell was developed and interfaced with the matrix-assisted laser desorption/ionization （MALDI） time-of-flight mass spectrometer for on-line bioaerosol detection and characterization,...An evaporation/condensation flow cell was developed and interfaced with the matrix-assisted laser desorption/ionization （MALDI） time-of-flight mass spectrometer for on-line bioaerosol detection and characterization, which allows matrix addition by condensation onto the laboratory-generated bioaerosol particles. The final coated particle exiting from the con- denser is then introduced into the aerodynamic particle sizer spectrometer or home-built aerosol laser time-of-flight mass spectrometer, and its aerodynamic size directly effects on the matrix-to-analyte molar ratio, which is very important for MALDI technique. In order to observe the protonated analyte molecular ion, and then determine the classification of bi- ological aerosols, the matrix-to-analyte molar ratio must be appropriate. Four experimental parameters, including the temperature of the heated reservoir, the initial particle size, its number concentration, and the matrix material, were tested experimentally to analyze their influences on the final particle size. This technique represents an on-line system of detection that has the potential to provide rapid and reliable identification of airborne biological aerosols.展开更多
Androgens play a central role in prostate cancer pathogenesis, and hence most of the patients respond to androgen deprivation therapies. However, patients tend to relapse with aggressive prostate cancer, which has bee...Androgens play a central role in prostate cancer pathogenesis, and hence most of the patients respond to androgen deprivation therapies. However, patients tend to relapse with aggressive prostate cancer, which has been termed as hormone refractory. To identify the proteins that mediate progression to the hormone-refractory state, we used protein-chip technology for mass profiling of patients＇ sera. This study included 16 patients with metastatic hormone-refractory prostate cancer who were initially treated with androgen deprivation therapy. Serum samples were collected from each patient at five time points： point A, pre-treatment; point B, at the nadir of the prostate- specific antigen （PSA） level; point C, PSA failure; point D, the early hormone-refractory phase; and point E, the late hormone-refractory phase. Using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry, we performed protein mass profiling of the patients＇ sera and identified a 6 640-Da peak that increased with disease progression. Target proteins were partially purified, and by amino acid sequencing the peak was identified as a fragment of apolipoprotein C-I （ApoC-I）. Serum ApoC-I protein levels increased with disease progression. On immunohistochemical analysis, the ApoC-i protein was found localized to the cytoplasm of the hormone-refractory cancer cells. In this study, we showed an increase in serum ApoC-I protein levels in prostate cancer patients during their progression to the hormone-refractory state, which suggests that ApoC-I protein is related to progression of prostate cancer. However, as the exact role of ApoC-I in prostate cancer pathogenesis is unclear, further research is required.展开更多
A simple method was developed for rapid and direct profiling of alkaloids in medical herbs via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry（MALDI-TOF MS）. The dry herbs were first gro...A simple method was developed for rapid and direct profiling of alkaloids in medical herbs via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry（MALDI-TOF MS）. The dry herbs were first ground to powder and passed through a stainless steel sieve, mixed with the matrix solution to form a homogeneous suspension, which was then directly applied to MALDI analysis. Several matrices were investigated and 2,5- dihydroxybenzoic acid（DHB） was chosen as the optimized one, and the particle with small size was found to favor the analysis. Using this method, the profiles of alkaloids in several medical herbs were readily obtained, and the toxicities of crude and processed Radix Aconiti Lateralis Preparata were compared via the relative intensities of the peaks of the corresponding toxic components shown in their MALDI spectra. This method therefore provides a rapid and reliable protocol for obtaining profiles of alkaloids in medical herbs by using MALDI-TOF MS.展开更多
Introduction Single nucleotide polymorphisms （SNPs） are the most abundant DNA markers in the human genome occurring at a frequency of one in every 500--1000 nucleotides. A variety of methods have been used for the ...Introduction Single nucleotide polymorphisms （SNPs） are the most abundant DNA markers in the human genome occurring at a frequency of one in every 500--1000 nucleotides. A variety of methods have been used for the analysis of single nucleotide polymorphisms, including restriction fragment length polymorphism （RFLP）, direct sequencing by using laser-induced fluorescence detectionTM, fluorescence energy transfer, MALDI-TOF MS combined with primer extension or invasive cleavage, and fluorescence polarization. During the past two decades, mass spectrometry has become a very popular tool in the analysis of biomolecules and is perfectly suited to the analysis of single nucleotide polymorphisms （SNPs） due to its speed, low cost, and accuracy. In this work, we used MALDI TOF mass spectrometry to detect the fragments of restriction endonuclease hydrolysis of PCR products flanking a SNP located at paraoxonase 1（Q192R）. Compared with electrophoresis, this method requires less time of analysis and possess a higher accuracy.展开更多
Surface-assisted laser desorption/ionization mass spectrometry(SALDI-MS)uses inorganic nanomaterials as matrixes to facilitate desorption and ionization of analytes.Compared with the traditional matrix-assisted laser ...Surface-assisted laser desorption/ionization mass spectrometry(SALDI-MS)uses inorganic nanomaterials as matrixes to facilitate desorption and ionization of analytes.Compared with the traditional matrix-assisted laser desorption/ionization mass spectrometry(MALDI-MS)technique,SALDI-MS has the advantages of less interference in the low mass range,better reproducibility and higher salt tolerance.It is highly suitable for the analysis of small molecule compounds.In recent years,researchers have developed a range of nanomaterials that are successfully applied to the field of small molecule drug and metabolite analysis including drug screening and quantification,drug delivery,metabolite profiling,biomarker discovery and so forth.This review summarizes the latest progress of SALDI-MS matrix materials such as metal-based,carbon-based,silica-based nanomaterials and organic framework nanomaterials and their applications.In addition,our perspective of SALDI-MS technology is also discussed for further advancement.展开更多
A novel sample preparation method of matrix-assisted laser desorption/ionization mass spectrometry for polystyrene was reported. Compared to the conventional dried-droplet method, the efficiency of ionization and sign...A novel sample preparation method of matrix-assisted laser desorption/ionization mass spectrometry for polystyrene was reported. Compared to the conventional dried-droplet method, the efficiency of ionization and signal intensity of mass spectra were improved. The mechanism was also analyzed.展开更多
Matrix-assisted Laser Desorption/Ionization with Time-of-flight Mass Spectrometry (MALDI-TOFMS) was investigated as a method for the rapid identifica-tion of species. Current demand in microbial identi-fication is how...Matrix-assisted Laser Desorption/Ionization with Time-of-flight Mass Spectrometry (MALDI-TOFMS) was investigated as a method for the rapid identifica-tion of species. Current demand in microbial identi-fication is how to compare unknown strains to the known one quickly, semi-automatically and accurately. In this paper, we present a software tool that allows flexibly microbial matching in a user-friendly way, by letting the users to customize comparison parameters including: in vitro transcription enzyme, mass tolerance,minimum fragment length, intensity threshold and corresponding weights. We provide three spectral scoring functions to compute the affin-ity between the species. Therefore, the precision of microbial comparison increases. To test and verify this tool, we employed experimental spectral data based on MALDI-TOFMS and the gene sequences of E.coli and Salmonella. This software is written in Java for cross-platform intention.展开更多
Native and methyl-esterified sialylated glycans were analyzed with 2,4,6-trihydroxyacetophenone（THAP）and 2,5-dihydroxybenzoic acid（DHB）as matrix by a matrix-assisted laser desorption/ionization time-of-flight mass...Native and methyl-esterified sialylated glycans were analyzed with 2,4,6-trihydroxyacetophenone（THAP）and 2,5-dihydroxybenzoic acid（DHB）as matrix by a matrix-assisted laser desorption/ionization time-of-flight mass spectrometer（MALDI-TOF MS）.High quality negative-ion spectra of commercial sialylated glycan were obtained with THAP as matrix.Detection limit of the glycan was less than 0.1 pmol.After methyl esterification of sialic acid（SA）residue,sialylated glycans were detected sensitively in the positive-ion mode using DHB as matrix.Neutral and sialylated glycans from the mixture of asialofetuin and fetuin were methylesterified and simultaneously recognized in one manipulation.Methyl esterification of SA residue offers a convenient and sensitive way to identify the structure of N-linked glycans for glycan profiling.展开更多
Elementary cholesterol was analyzed with IR laser desorption/tunable synchrotron vacuum ultraviolet photoionization mass spectrometry. An exclusive molecular ion of cholesterol is observed by near threshold single-pho...Elementary cholesterol was analyzed with IR laser desorption/tunable synchrotron vacuum ultraviolet photoionization mass spectrometry. An exclusive molecular ion of cholesterol is observed by near threshold single-photon ionization with high efficiency. Fragments are yielded with the increase of photon energy. The structures of various fragments are determined with commercial electron ionization time-of-flight mass spectrometry. Dominant fragmentation pathways are discussed in detail with the aid of ab initio calculations.展开更多
High-molecular-weight disinfection byproducts(HMW DBPs)have been increasingly recognized as contaminants that pose potential hazards to human health.However,reliable analytical methods for exploring the properties and...High-molecular-weight disinfection byproducts(HMW DBPs)have been increasingly recognized as contaminants that pose potential hazards to human health.However,reliable analytical methods for exploring the properties and structures of these DBPs remain limited.This study presents a novel approach for detecting and identifying HMW DBPs via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.The experimental conditions were optimized by selecting super-2,5-dihydroxybenzoic acid(super-DHB)as the matrix and sodium trifluoroacetate as the cationization agent and employing the sandwich deposition method in reflection-positive ion mode with 90%laser intensity,resulting in the highest peak intensity for HMW DBPs.These optimized conditions enhanced peak reproducibility,yielding a signal-to-noise ratio of 134.9 and a coefficient of variation of 3.8%.With the new approach,five HMW DBPs were detected in simulated drinking water and identified as oligosaccharide carboxylic acids via isotopic pattern analysis,tandem mass spectrometry analysis in laser-induced dissociation mode,and database verification.展开更多
Hydrogen desorption kinetics and characteristics,residual hydrogen content and activation energy of TC21 alloy were investigated by the constant volume method.Results show that hydrogen desorption temperature and init...Hydrogen desorption kinetics and characteristics,residual hydrogen content and activation energy of TC21 alloy were investigated by the constant volume method.Results show that hydrogen desorption temperature and initial hydrogen pressure affect hydrogen desorption characteristics of TC21 alloy.The hydrogen desorption process is mainly dominated by nucleation and growth process(kt=[-ln(1-α)]^(2/3)),chemical reaction process(kt=(1-α)^(-1/2))and three-dimensional diffusion process(kt=[1-(1-α)^(1/3)]^(1/2))when the hydrogenated TC21 alloy is dehydrogenated at temperatures of 700-940°C.When the hydrogenated TC21 alloy releases hydrogen,the following relationship exists among the rate constants of each process:k(chemical reaction process)>k(nucleation and growth process)>k(three-dimensional diffusion process).The residual hydrogen content of the hydrogenated TC21 alloy after hydrogen desorption decreases gradually with the increase in hydrogen desorption temperature,and increases gradually with the increase in the initial hydrogen pressure.The activation energy of TC21 alloy in the process of hydrogen desorption is about 26.663 kJ/mol.展开更多
Microplastics loaded with phenanthrene and derivatives are widely detected in aquatic environments,and the coating of natural minerals or organic macromolecules may change the environmental behavior of microplastics.I...Microplastics loaded with phenanthrene and derivatives are widely detected in aquatic environments,and the coating of natural minerals or organic macromolecules may change the environmental behavior of microplastics.In this study,three kinds of composites with different coverage were prepared by coating goethite on the surface of polyvinyl chloride microplastics to investigate the adsorption and desorption behavior of phenanthrene(PHE)and 1-hydroxyphenanthrene(1-OHPHE),and the effect of mucin on desorption was inves-tigated.The results showed that goethite promoted the adsorption of PHE and 1-OHPHE by increasing the specific surface area of the composites.With the increase of the cover de-gree,the adsorption of PHE decreased because of the decrease in hydrophobicity;while the adsorption of 1-OHPHE initially increased and then decreased with the contributions of hydrophobic interaction and hydrogen bond.The adsorption of 1-OHPHE could be influenced by the pH and ionic strength primarily through electrostatic interactions and Ca2+bridg-ing.The goethite significantly increased the desorption hysteresis for two chemicals due to the complicated pore structures and increased adsorption affinity.Mucin promoted the desorption of PHE through competitive adsorption,and inhibit the desorption of 1-OHPHE through hydrophobic interaction,hydrogen bonding and Ca2+bridging.This study elucidated the effects of natural minerals on the adsorption and desorption behavior of organic pollutants on microplastics,briefly discussed the effects of organic macromolecules on the desorption behavior of pollutants with different properties,and emphasized the different environmental behaviors of pollutants.展开更多
This paper summarizes the mechanisms and environmental effects of interactions between microplastics and surfactants: surfactants adsorb onto microplastics surfaces through hydrophobic interactions and electrostatic f...This paper summarizes the mechanisms and environmental effects of interactions between microplastics and surfactants: surfactants adsorb onto microplastics surfaces through hydrophobic interactions and electrostatic forces, changing their surface properties and transport behavior. In addition, microplastics act as carriers influencing surfactant distribution. Environmental factors (pH, ionic strength, etc. ) significantly regulate this process. Current research still has limitations in areas such as desorption kinetics and combined pollution effects, necessitating in-depth studies under environmentally relevant conditions to provide a basis for risk assessment.展开更多
Understanding how different vegetation-based restoration practices alter soil chemical and microbial characteristics is crucial,as restoration practices influence phosphorus(P)transformation and fractions and modify P...Understanding how different vegetation-based restoration practices alter soil chemical and microbial characteristics is crucial,as restoration practices influence phosphorus(P)transformation and fractions and modify P adsorption behavior during the restoration process of degraded land.This study investigated the impacts of vegetation-based restoration practices on soil chemical and microbial parameters,P fractions,and patterns of P adsorption and desorption,and highlighted the combined influence on P availability.To evaluate the impact of vegetation-based restoration practices on P fractions and adsorption behavior in the semi-arid degraded land in India,this study compared three distinct tree-based restoration systems,including Leucaena leucocephala(Lam.)de Wit-based silviculture system(SCS),Acacia nilotica(L.)Willd.ex Delile-based silvopasture system(SPS),and Emblica officinalis Gaertn-based hortipasture system(HPS),with a natural grassland system(NGS)and a degraded fallow system(FS)as control.The soil samples across various soil depths(0-15,15-30,and 30-45 cm)were collected.The findings demonstrated that SCS,SPS,and HPS significantly improved soil organic carbon(SOC)and nutrient availability.Moreover,SCS and SPS resulted in increased microbial biomass phosphorus(MBP)content and phosphatase enzyme activity.The P fractionation analysis revealed that ferrum-associated phosphorus(Fe-P)was the major P fraction,followed by aluminum-associated phosphorus(Al-P),reflecting the dominance of ferrum(Fe)and aluminum(Al)oxides in the semi-arid degraded land.Compared with FS,vegetation-based restoration practices significantly increased various P fractions across soil depths.Additionally,P adsorption and desorption analysis indicated a lower adsorption capacity in tree-based restoration systems than in FS,with FS soils adsorbing higher P quantities in the adsorption phase but releasing less P during the desorption phase.This study revealed that degraded soils responded positively to ecological restoration in terms of P fraction and desorption behavior,influencing the resupply of P in restoration systems.Consequently,litter rich N-fixing tree-based restoration systems(i.e.,SCS and SPS)increased total phosphorus(TP)stock for plants and sustained the potential for long-term P supply in semi-arid ecosystems.With the widespread adoption of restoration practices across degraded landscapes,SCS and SPS would significantly contribute to soil restoration and improve productivity by maintaining the soil P supply in semi-arid ecosystems in India.展开更多
Flotation is the most common method to recover valuable minerals by selective adsorption of collectors on target mineral surfaces.However,in subsequent hydrometallurgy of mineral flotation concentrates,the adsorbed co...Flotation is the most common method to recover valuable minerals by selective adsorption of collectors on target mineral surfaces.However,in subsequent hydrometallurgy of mineral flotation concentrates,the adsorbed collectors must be desorbed since it can adversely affect the efficiency of metallurgical process and produce wastewater.ZL,as a fatty acid mixture,is a typical industrially used collector for scheelite flotation in China.Sodium oleate(NaOL)has similar fatty acid group as ZL.In this study,the desorption behavior of NaOL/ZL from scheelite surface by a physical method of stirring at a low temperature was investigated.NaOL desorption tests of single mineral showed that a desorption rate of 77.75% for NaOL from scheelite surface into pulp was achieved in a stirring speed of2500 r/min at 5℃in a neutral environment.Under the above desorption condition,in the pulp containing desorbed collector by adding extra 30% normal NaOL dosage,the scheelite recovery reached about 95% in the single mineral flotation test.Desorption and reuse of ZL collector for the flotation of real scheelite ore showed only a 75%normal dosage of ZL could produce a qualified rough concentrate.The atomic force microscope(AFM)tests showed that after desorption treatment of low temperature and strong stirring,the dense strip-like structure of NaOL on the scheelite surface was destroyed to be speck-like.Molecular dynamics simulations(MDS)demonstrated that the adsorption energy between NaOL and scheelite surface was more negative at 25℃(-13.39 kcal/mol)than at 5℃(-11.50 kcal/mol)in a neutral pH,indicating that a low temperature was beneficial for the desorption of collector from mineral surface.Due to its simplicity and economy,the method we proposed of desorption of collector from mineral surface and its reuse for flotation has a great potential for industrial application.展开更多
Soil contamination remains a global problem,and numerous studies have been published for investigating soil re-mediation.Thermal desorption remediation(TDR)can significantly reduce the contaminants in the soil within ...Soil contamination remains a global problem,and numerous studies have been published for investigating soil re-mediation.Thermal desorption remediation(TDR)can significantly reduce the contaminants in the soil within a short time and consequently has been used worldwide.However,the soil properties respond to TDR differently and are dependent on the experimental set-up.The causative mechanisms of these differences are yet to be fully elucidated.A statistical meta-analysis was thus undertaken to evaluate the TDR treatment effects on soil properties and plant per-formance.This review pointed out that soil clay was reduced by 54.2%,while soil sand content was enhanced by 15.2% after TDR.This might be due to the release of cementing agents from clay minerals that resulted in the formation of soil aggregates.Soil electrical conductivity enhanced by 69.5% after TDR,which might be due to the heating-induced loss of structural hydroxyl groups and the consequent liberation of ions.The treatment of TDR leads to the reduction of plant germination rate,length,and biomass by 19.4%,44.8%,and 20.2%,respectively,compared to that of control soil.This might be due to the residue of contaminants and the loss of soil fertility during the thermal process that inhibited plant germination and growth.Soil pH and sulfate content increased with heating temperature increased,while soil enzyme activities decreased with thermal temperature increased.Overall,the results suggested that TDR treatment has inhibited plant growth as well as ecological restoration.展开更多
Ingestion of microplastics by various organisms has been widely evidenced.Chemicals associated with microplastics(MPs)may be released to digestive tracts upon ingestion.However,the effect of aging and temperature on t...Ingestion of microplastics by various organisms has been widely evidenced.Chemicals associated with microplastics(MPs)may be released to digestive tracts upon ingestion.However,the effect of aging and temperature on the chemical desorption for MPs remains poorly understood.The exposure of polyethylene(PE)particles to UV radiation in dry air,tap water,and sea water was conducted to mimic the aging process of MPs in different environments.Polychlorinated biphenyls(PCBs),as a typical hydrophobic organic contaminant,were preloaded in these aged and pristine PE.The desorption was performed by exposing preloaded PE particles in simulated gastric and gut fluids at 25℃and 40℃.After UV aging,the average diameter of PE particles decreased rapidly with aging time,indicating continuously fragmentation of PE under UV exposure.The desorption of PCBs from PE particles under different conditions varied from 7%to 40%,and that from aged PE in gut fluid at 37℃was significantly higher than those under other conditions(P<0.05).Furthermore,a clear declining trend was observed as lg K_(ow)(octanol-water partition coefficient)value increased.The aging process,hydrophobicity of chemicals,and incubation temperature were important factors on the desorption of PCBs from PE.The present study helps understand the desorption of PCBs from microplastics and the potential risks of microplastics ingestion by organisms.展开更多
Catalytic amine-solvent regeneration has been validated as an energy-saving strategy for CO_(2) chemisorption by boosting reaction kinetics under mild conditions.The upscale performance evaluation and longterm durabil...Catalytic amine-solvent regeneration has been validated as an energy-saving strategy for CO_(2) chemisorption by boosting reaction kinetics under mild conditions.The upscale performance evaluation and longterm durability are indispensable steps for industrial application but have been scarcely reported thus far.Here,we report a ZrO_(2)/Al_(2)O_(3) pack catalyst that possesses strong metal oxide-support interactions,a porous structure,active and stable Zr-O-Al coordination,promoted proton transfer and a 40.7% decrease in the energy activation of carbamate decomposition,which significantly accelerates CO_(2) desorption kinetics.The upscale experiment and cost evaluation based on industrial flue gas revealed that the use of packing catalysts can reduce energy consumption by 27.56% and optimize the overall cost by 10.49%.The active sites present excellent stability in alkaline solvents.This work is the first to investigate the ability of high-technology readiness(technology readiness level at 6(TRL 6))for catalytic aminesolvent regeneration,providing valuable insights for potential applications involving efficient CO_(2) capture with catalyst assistance.展开更多
Background Freshwater snails of the genera Bulinus spp.,Biomphalaria spp.,and Oncomelania spp.are the main intermediate hosts of human and animal schistosomiasis.Identification of these snails has long been based on m...Background Freshwater snails of the genera Bulinus spp.,Biomphalaria spp.,and Oncomelania spp.are the main intermediate hosts of human and animal schistosomiasis.Identification of these snails has long been based on mor-phological and/or genomic criteria,which have their limitations.These limitations include a lack of precision for the morphological tool and cost and time for the DNA-based approach.Recently,Matrix-Assisted Laser Desorp-tion/lonization Time-Of-Flight(MALDI-TOF)mass spectrometry,a new tool used which is routinely in clinical microbi-ology,has emerged in the field of malacology for the identification of freshwater snails.This study aimed to evaluate the ability of MALDI-TOF MS to identify Biomphalaria pfeifferi and Bulinus forskali snail populations according to their geographicalorigin.Methods This study was conducted on 101 Bi.pfeifferi and 81 Bu.forskali snails collected in three distinct geo-graphical areas of Senegal(the North-East,South-East and central part of the country),and supplemented with wild and laboratory strains.Specimens which had previously been morphologically described were identified by MALDl-TOF MS[identification log score values(LSV)≥1.7],after an initial blind test using the pre-existing database.After DNA-based identification,new reference spectra of Bi.pfeiferi(n=10)and Bu.forskali(n=5)from the geographical areas were added to the MALDI-TOF spectral database.The final blind test against this updated database was per-formed to assess identification at the geographic source level.Results MALDI-TOF MS correctly identified 92.1%of 101 Bi.pfeifferi snails and 98.8%of 81 Bu.forskali snails.At the final blind test,88%of 166 specimens were correctly identified according to both their species and sampling site,with LSVs ranging from 1.74 to 2.70.The geographical source was adequately identified in 90.1%of 91 Bi.pfeifferi and 85.3%of 75 Bu.forskalii samples.Conclusions Our findings demonstrate that MALDI-TOF MS can identify and differentiate snail populations according to geographical origin.It outperforms the current DNA-based approaches in discriminating laboratory from wild strains.This inexpensive high-throughput approach is likely to further revolutionise epidemiological studies in areas which are endemic for schistosomiasis.展开更多
Gelsemium elegans Benth alkaloids are the main components of G.elegans and can cause acute toxicosis or even death.Although several studies have reported methods for detecting G.elegans alkaloids,a high-throughput and...Gelsemium elegans Benth alkaloids are the main components of G.elegans and can cause acute toxicosis or even death.Although several studies have reported methods for detecting G.elegans alkaloids,a high-throughput and environmental-friendly strategy for detection of multiple G.elegans alkaloids has not been realized.In this work,a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry method was developed for rapid detection of G.elegans alkaloids in human plasma and urine for diagnosis of poisoning.Multiple matrices and crys-tal spotting methods were evaluated to obtain stable and high peak intensities without“sweet spot”.We verified the methodology and obtained excellent results.The matrix effects with different dilutions were compared and good recoveries and a low relative standard deviation were obtained with a 40-fold dilution.This method could shorten the analysis time and greatly reduce the consumption of chemical solvents.Furthermore,it could be applied to quan-titative assessment of G.elegans alkaloid poisoning incidents.展开更多
文摘An evaporation/condensation flow cell was developed and interfaced with the matrix-assisted laser desorption/ionization （MALDI） time-of-flight mass spectrometer for on-line bioaerosol detection and characterization, which allows matrix addition by condensation onto the laboratory-generated bioaerosol particles. The final coated particle exiting from the con- denser is then introduced into the aerodynamic particle sizer spectrometer or home-built aerosol laser time-of-flight mass spectrometer, and its aerodynamic size directly effects on the matrix-to-analyte molar ratio, which is very important for MALDI technique. In order to observe the protonated analyte molecular ion, and then determine the classification of bi- ological aerosols, the matrix-to-analyte molar ratio must be appropriate. Four experimental parameters, including the temperature of the heated reservoir, the initial particle size, its number concentration, and the matrix material, were tested experimentally to analyze their influences on the final particle size. This technique represents an on-line system of detection that has the potential to provide rapid and reliable identification of airborne biological aerosols.
文摘Androgens play a central role in prostate cancer pathogenesis, and hence most of the patients respond to androgen deprivation therapies. However, patients tend to relapse with aggressive prostate cancer, which has been termed as hormone refractory. To identify the proteins that mediate progression to the hormone-refractory state, we used protein-chip technology for mass profiling of patients＇ sera. This study included 16 patients with metastatic hormone-refractory prostate cancer who were initially treated with androgen deprivation therapy. Serum samples were collected from each patient at five time points： point A, pre-treatment; point B, at the nadir of the prostate- specific antigen （PSA） level; point C, PSA failure; point D, the early hormone-refractory phase; and point E, the late hormone-refractory phase. Using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry, we performed protein mass profiling of the patients＇ sera and identified a 6 640-Da peak that increased with disease progression. Target proteins were partially purified, and by amino acid sequencing the peak was identified as a fragment of apolipoprotein C-I （ApoC-I）. Serum ApoC-I protein levels increased with disease progression. On immunohistochemical analysis, the ApoC-i protein was found localized to the cytoplasm of the hormone-refractory cancer cells. In this study, we showed an increase in serum ApoC-I protein levels in prostate cancer patients during their progression to the hormone-refractory state, which suggests that ApoC-I protein is related to progression of prostate cancer. However, as the exact role of ApoC-I in prostate cancer pathogenesis is unclear, further research is required.
基金Supported by the Major State Basic Research Development Program of China(No.2006CB5047060)the National Natural Science Foundation of China(Nos.30672600, 30772721)the Natural Science Foundation of Jilin Province, China (No.20060902)
文摘A simple method was developed for rapid and direct profiling of alkaloids in medical herbs via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry（MALDI-TOF MS）. The dry herbs were first ground to powder and passed through a stainless steel sieve, mixed with the matrix solution to form a homogeneous suspension, which was then directly applied to MALDI analysis. Several matrices were investigated and 2,5- dihydroxybenzoic acid（DHB） was chosen as the optimized one, and the particle with small size was found to favor the analysis. Using this method, the profiles of alkaloids in several medical herbs were readily obtained, and the toxicities of crude and processed Radix Aconiti Lateralis Preparata were compared via the relative intensities of the peaks of the corresponding toxic components shown in their MALDI spectra. This method therefore provides a rapid and reliable protocol for obtaining profiles of alkaloids in medical herbs by using MALDI-TOF MS.
文摘Introduction Single nucleotide polymorphisms （SNPs） are the most abundant DNA markers in the human genome occurring at a frequency of one in every 500--1000 nucleotides. A variety of methods have been used for the analysis of single nucleotide polymorphisms, including restriction fragment length polymorphism （RFLP）, direct sequencing by using laser-induced fluorescence detectionTM, fluorescence energy transfer, MALDI-TOF MS combined with primer extension or invasive cleavage, and fluorescence polarization. During the past two decades, mass spectrometry has become a very popular tool in the analysis of biomolecules and is perfectly suited to the analysis of single nucleotide polymorphisms （SNPs） due to its speed, low cost, and accuracy. In this work, we used MALDI TOF mass spectrometry to detect the fragments of restriction endonuclease hydrolysis of PCR products flanking a SNP located at paraoxonase 1（Q192R）. Compared with electrophoresis, this method requires less time of analysis and possess a higher accuracy.
基金State Key Laboratory of Natural and Biomimetic Drugs(Peking University)the National Natural Science Foundation of China(Grant No.21804123)。
文摘Surface-assisted laser desorption/ionization mass spectrometry(SALDI-MS)uses inorganic nanomaterials as matrixes to facilitate desorption and ionization of analytes.Compared with the traditional matrix-assisted laser desorption/ionization mass spectrometry(MALDI-MS)technique,SALDI-MS has the advantages of less interference in the low mass range,better reproducibility and higher salt tolerance.It is highly suitable for the analysis of small molecule compounds.In recent years,researchers have developed a range of nanomaterials that are successfully applied to the field of small molecule drug and metabolite analysis including drug screening and quantification,drug delivery,metabolite profiling,biomarker discovery and so forth.This review summarizes the latest progress of SALDI-MS matrix materials such as metal-based,carbon-based,silica-based nanomaterials and organic framework nanomaterials and their applications.In addition,our perspective of SALDI-MS technology is also discussed for further advancement.
文摘A novel sample preparation method of matrix-assisted laser desorption/ionization mass spectrometry for polystyrene was reported. Compared to the conventional dried-droplet method, the efficiency of ionization and signal intensity of mass spectra were improved. The mechanism was also analyzed.
文摘Matrix-assisted Laser Desorption/Ionization with Time-of-flight Mass Spectrometry (MALDI-TOFMS) was investigated as a method for the rapid identifica-tion of species. Current demand in microbial identi-fication is how to compare unknown strains to the known one quickly, semi-automatically and accurately. In this paper, we present a software tool that allows flexibly microbial matching in a user-friendly way, by letting the users to customize comparison parameters including: in vitro transcription enzyme, mass tolerance,minimum fragment length, intensity threshold and corresponding weights. We provide three spectral scoring functions to compute the affin-ity between the species. Therefore, the precision of microbial comparison increases. To test and verify this tool, we employed experimental spectral data based on MALDI-TOFMS and the gene sequences of E.coli and Salmonella. This software is written in Java for cross-platform intention.
基金Supported by the National Natural Science Foundation of China(30800193)Grant from Centre for International Mobility(CIMO),Finland
文摘Native and methyl-esterified sialylated glycans were analyzed with 2,4,6-trihydroxyacetophenone（THAP）and 2,5-dihydroxybenzoic acid（DHB）as matrix by a matrix-assisted laser desorption/ionization time-of-flight mass spectrometer（MALDI-TOF MS）.High quality negative-ion spectra of commercial sialylated glycan were obtained with THAP as matrix.Detection limit of the glycan was less than 0.1 pmol.After methyl esterification of sialic acid（SA）residue,sialylated glycans were detected sensitively in the positive-ion mode using DHB as matrix.Neutral and sialylated glycans from the mixture of asialofetuin and fetuin were methylesterified and simultaneously recognized in one manipulation.Methyl esterification of SA residue offers a convenient and sensitive way to identify the structure of N-linked glycans for glycan profiling.
基金Ⅴ. ACKNOWLEDGMENTS This work was supported by the Chinese Academy of Sciences （No.YZ200764）, the National Natural Science Foundation of China （No.10705026）, the National Basic Research Program of China （No.2007CB815204）, and the China Postdoctoral Science Foundation （No.20070410793 and No.20070420726）.
文摘Elementary cholesterol was analyzed with IR laser desorption/tunable synchrotron vacuum ultraviolet photoionization mass spectrometry. An exclusive molecular ion of cholesterol is observed by near threshold single-photon ionization with high efficiency. Fragments are yielded with the increase of photon energy. The structures of various fragments are determined with commercial electron ionization time-of-flight mass spectrometry. Dominant fragmentation pathways are discussed in detail with the aid of ab initio calculations.
基金supported by the National Natural Science Foundation of China(Nos.22322605,22176089,22376099,and 22476096)the Fundamental Research Funds for the Central Universities,China(No.2024300400)the Natural Science Foundation of Jiangsu Province,China(No.BK20211509).
文摘High-molecular-weight disinfection byproducts(HMW DBPs)have been increasingly recognized as contaminants that pose potential hazards to human health.However,reliable analytical methods for exploring the properties and structures of these DBPs remain limited.This study presents a novel approach for detecting and identifying HMW DBPs via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.The experimental conditions were optimized by selecting super-2,5-dihydroxybenzoic acid(super-DHB)as the matrix and sodium trifluoroacetate as the cationization agent and employing the sandwich deposition method in reflection-positive ion mode with 90%laser intensity,resulting in the highest peak intensity for HMW DBPs.These optimized conditions enhanced peak reproducibility,yielding a signal-to-noise ratio of 134.9 and a coefficient of variation of 3.8%.With the new approach,five HMW DBPs were detected in simulated drinking water and identified as oligosaccharide carboxylic acids via isotopic pattern analysis,tandem mass spectrometry analysis in laser-induced dissociation mode,and database verification.
基金National Natural Science Foundation of China(52275328,51875157)。
文摘Hydrogen desorption kinetics and characteristics,residual hydrogen content and activation energy of TC21 alloy were investigated by the constant volume method.Results show that hydrogen desorption temperature and initial hydrogen pressure affect hydrogen desorption characteristics of TC21 alloy.The hydrogen desorption process is mainly dominated by nucleation and growth process(kt=[-ln(1-α)]^(2/3)),chemical reaction process(kt=(1-α)^(-1/2))and three-dimensional diffusion process(kt=[1-(1-α)^(1/3)]^(1/2))when the hydrogenated TC21 alloy is dehydrogenated at temperatures of 700-940°C.When the hydrogenated TC21 alloy releases hydrogen,the following relationship exists among the rate constants of each process:k(chemical reaction process)>k(nucleation and growth process)>k(three-dimensional diffusion process).The residual hydrogen content of the hydrogenated TC21 alloy after hydrogen desorption decreases gradually with the increase in hydrogen desorption temperature,and increases gradually with the increase in the initial hydrogen pressure.The activation energy of TC21 alloy in the process of hydrogen desorption is about 26.663 kJ/mol.
基金supported by the National Natural Science Foundation of China(Nos.42077337 and 42277228)the Guangdong Basic and Applied Basic Research Foundation(No.2020A1515011560)the Science and Technology Planning Project of Guangzhou(Nos.202002030297 and 202002020072).
文摘Microplastics loaded with phenanthrene and derivatives are widely detected in aquatic environments,and the coating of natural minerals or organic macromolecules may change the environmental behavior of microplastics.In this study,three kinds of composites with different coverage were prepared by coating goethite on the surface of polyvinyl chloride microplastics to investigate the adsorption and desorption behavior of phenanthrene(PHE)and 1-hydroxyphenanthrene(1-OHPHE),and the effect of mucin on desorption was inves-tigated.The results showed that goethite promoted the adsorption of PHE and 1-OHPHE by increasing the specific surface area of the composites.With the increase of the cover de-gree,the adsorption of PHE decreased because of the decrease in hydrophobicity;while the adsorption of 1-OHPHE initially increased and then decreased with the contributions of hydrophobic interaction and hydrogen bond.The adsorption of 1-OHPHE could be influenced by the pH and ionic strength primarily through electrostatic interactions and Ca2+bridg-ing.The goethite significantly increased the desorption hysteresis for two chemicals due to the complicated pore structures and increased adsorption affinity.Mucin promoted the desorption of PHE through competitive adsorption,and inhibit the desorption of 1-OHPHE through hydrophobic interaction,hydrogen bonding and Ca2+bridging.This study elucidated the effects of natural minerals on the adsorption and desorption behavior of organic pollutants on microplastics,briefly discussed the effects of organic macromolecules on the desorption behavior of pollutants with different properties,and emphasized the different environmental behaviors of pollutants.
基金Supported by Zhaoqing University Innovation and Entrepreneurship Training Program for College Students (X202410580130).
文摘This paper summarizes the mechanisms and environmental effects of interactions between microplastics and surfactants: surfactants adsorb onto microplastics surfaces through hydrophobic interactions and electrostatic forces, changing their surface properties and transport behavior. In addition, microplastics act as carriers influencing surfactant distribution. Environmental factors (pH, ionic strength, etc. ) significantly regulate this process. Current research still has limitations in areas such as desorption kinetics and combined pollution effects, necessitating in-depth studies under environmentally relevant conditions to provide a basis for risk assessment.
基金funded by Indian Council of Agricultural Research,Ministry of Agriculture and Farmers Welfare,India(AGRIL.EDN/1/1/2022-EXAM CELL).
文摘Understanding how different vegetation-based restoration practices alter soil chemical and microbial characteristics is crucial,as restoration practices influence phosphorus(P)transformation and fractions and modify P adsorption behavior during the restoration process of degraded land.This study investigated the impacts of vegetation-based restoration practices on soil chemical and microbial parameters,P fractions,and patterns of P adsorption and desorption,and highlighted the combined influence on P availability.To evaluate the impact of vegetation-based restoration practices on P fractions and adsorption behavior in the semi-arid degraded land in India,this study compared three distinct tree-based restoration systems,including Leucaena leucocephala(Lam.)de Wit-based silviculture system(SCS),Acacia nilotica(L.)Willd.ex Delile-based silvopasture system(SPS),and Emblica officinalis Gaertn-based hortipasture system(HPS),with a natural grassland system(NGS)and a degraded fallow system(FS)as control.The soil samples across various soil depths(0-15,15-30,and 30-45 cm)were collected.The findings demonstrated that SCS,SPS,and HPS significantly improved soil organic carbon(SOC)and nutrient availability.Moreover,SCS and SPS resulted in increased microbial biomass phosphorus(MBP)content and phosphatase enzyme activity.The P fractionation analysis revealed that ferrum-associated phosphorus(Fe-P)was the major P fraction,followed by aluminum-associated phosphorus(Al-P),reflecting the dominance of ferrum(Fe)and aluminum(Al)oxides in the semi-arid degraded land.Compared with FS,vegetation-based restoration practices significantly increased various P fractions across soil depths.Additionally,P adsorption and desorption analysis indicated a lower adsorption capacity in tree-based restoration systems than in FS,with FS soils adsorbing higher P quantities in the adsorption phase but releasing less P during the desorption phase.This study revealed that degraded soils responded positively to ecological restoration in terms of P fraction and desorption behavior,influencing the resupply of P in restoration systems.Consequently,litter rich N-fixing tree-based restoration systems(i.e.,SCS and SPS)increased total phosphorus(TP)stock for plants and sustained the potential for long-term P supply in semi-arid ecosystems.With the widespread adoption of restoration practices across degraded landscapes,SCS and SPS would significantly contribute to soil restoration and improve productivity by maintaining the soil P supply in semi-arid ecosystems in India.
基金financially supported by the National Natural Science Foundation of China(Nos.52304314 and U23A20602)the Open Fund of the Key Laboratory of Mineral Metallurgical Resources Utilization and Pollution Control,Ministry of Ecology and Environment+3 种基金China(No.HB202406)the Fundamental Research Funds for the Central Universities of Central South University,China(Nos.CX20240021 and 2024ZZTS0008)the Innovation and Entrepreneurship Funding Project for College Students of Central South UniversityChina(No.S202410533166)。
文摘Flotation is the most common method to recover valuable minerals by selective adsorption of collectors on target mineral surfaces.However,in subsequent hydrometallurgy of mineral flotation concentrates,the adsorbed collectors must be desorbed since it can adversely affect the efficiency of metallurgical process and produce wastewater.ZL,as a fatty acid mixture,is a typical industrially used collector for scheelite flotation in China.Sodium oleate(NaOL)has similar fatty acid group as ZL.In this study,the desorption behavior of NaOL/ZL from scheelite surface by a physical method of stirring at a low temperature was investigated.NaOL desorption tests of single mineral showed that a desorption rate of 77.75% for NaOL from scheelite surface into pulp was achieved in a stirring speed of2500 r/min at 5℃in a neutral environment.Under the above desorption condition,in the pulp containing desorbed collector by adding extra 30% normal NaOL dosage,the scheelite recovery reached about 95% in the single mineral flotation test.Desorption and reuse of ZL collector for the flotation of real scheelite ore showed only a 75%normal dosage of ZL could produce a qualified rough concentrate.The atomic force microscope(AFM)tests showed that after desorption treatment of low temperature and strong stirring,the dense strip-like structure of NaOL on the scheelite surface was destroyed to be speck-like.Molecular dynamics simulations(MDS)demonstrated that the adsorption energy between NaOL and scheelite surface was more negative at 25℃(-13.39 kcal/mol)than at 5℃(-11.50 kcal/mol)in a neutral pH,indicating that a low temperature was beneficial for the desorption of collector from mineral surface.Due to its simplicity and economy,the method we proposed of desorption of collector from mineral surface and its reuse for flotation has a great potential for industrial application.
基金the financial sponsorship from the National Key R&D Program of China(No.2023YFC3905800)Youth Innovation Promotion Association CAS(2021349)+5 种基金Guangdong Youth Talent Support Program(2021TQ06L121)State Key Laboratory of Subtropical Building Science in South China University of Technology(2022ZC01)Shenzhen Science and Technology Program(KCXFZ20211020163816023)financially supported by the Natural Science Foundation of Wuhan(No.2024040801020271)the Fundamental Research Funds for Central Public Welfare Research Institutes(No.CKSF20241004/YT)the support from FINNCERES flagship and tenure track fund(91160169(TT/Bordoloi)。
文摘Soil contamination remains a global problem,and numerous studies have been published for investigating soil re-mediation.Thermal desorption remediation(TDR)can significantly reduce the contaminants in the soil within a short time and consequently has been used worldwide.However,the soil properties respond to TDR differently and are dependent on the experimental set-up.The causative mechanisms of these differences are yet to be fully elucidated.A statistical meta-analysis was thus undertaken to evaluate the TDR treatment effects on soil properties and plant per-formance.This review pointed out that soil clay was reduced by 54.2%,while soil sand content was enhanced by 15.2% after TDR.This might be due to the release of cementing agents from clay minerals that resulted in the formation of soil aggregates.Soil electrical conductivity enhanced by 69.5% after TDR,which might be due to the heating-induced loss of structural hydroxyl groups and the consequent liberation of ions.The treatment of TDR leads to the reduction of plant germination rate,length,and biomass by 19.4%,44.8%,and 20.2%,respectively,compared to that of control soil.This might be due to the residue of contaminants and the loss of soil fertility during the thermal process that inhibited plant germination and growth.Soil pH and sulfate content increased with heating temperature increased,while soil enzyme activities decreased with thermal temperature increased.Overall,the results suggested that TDR treatment has inhibited plant growth as well as ecological restoration.
基金Supported by the National Natural Science Foundation of China(No.21936004)the Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(No.SML2021SP208)the Fundamental Research Funds for the Central Universities(No.21623118)。
文摘Ingestion of microplastics by various organisms has been widely evidenced.Chemicals associated with microplastics(MPs)may be released to digestive tracts upon ingestion.However,the effect of aging and temperature on the chemical desorption for MPs remains poorly understood.The exposure of polyethylene(PE)particles to UV radiation in dry air,tap water,and sea water was conducted to mimic the aging process of MPs in different environments.Polychlorinated biphenyls(PCBs),as a typical hydrophobic organic contaminant,were preloaded in these aged and pristine PE.The desorption was performed by exposing preloaded PE particles in simulated gastric and gut fluids at 25℃and 40℃.After UV aging,the average diameter of PE particles decreased rapidly with aging time,indicating continuously fragmentation of PE under UV exposure.The desorption of PCBs from PE particles under different conditions varied from 7%to 40%,and that from aged PE in gut fluid at 37℃was significantly higher than those under other conditions(P<0.05).Furthermore,a clear declining trend was observed as lg K_(ow)(octanol-water partition coefficient)value increased.The aging process,hydrophobicity of chemicals,and incubation temperature were important factors on the desorption of PCBs from PE.The present study helps understand the desorption of PCBs from microplastics and the potential risks of microplastics ingestion by organisms.
基金supported by the National Natural Science Foundation of China(52300134 and 22106084)the China Postdoctoral Science Foundation(2022TQ0175,2023M741931,and 2022T150350).
文摘Catalytic amine-solvent regeneration has been validated as an energy-saving strategy for CO_(2) chemisorption by boosting reaction kinetics under mild conditions.The upscale performance evaluation and longterm durability are indispensable steps for industrial application but have been scarcely reported thus far.Here,we report a ZrO_(2)/Al_(2)O_(3) pack catalyst that possesses strong metal oxide-support interactions,a porous structure,active and stable Zr-O-Al coordination,promoted proton transfer and a 40.7% decrease in the energy activation of carbamate decomposition,which significantly accelerates CO_(2) desorption kinetics.The upscale experiment and cost evaluation based on industrial flue gas revealed that the use of packing catalysts can reduce energy consumption by 27.56% and optimize the overall cost by 10.49%.The active sites present excellent stability in alkaline solvents.This work is the first to investigate the ability of high-technology readiness(technology readiness level at 6(TRL 6))for catalytic aminesolvent regeneration,providing valuable insights for potential applications involving efficient CO_(2) capture with catalyst assistance.
文摘Background Freshwater snails of the genera Bulinus spp.,Biomphalaria spp.,and Oncomelania spp.are the main intermediate hosts of human and animal schistosomiasis.Identification of these snails has long been based on mor-phological and/or genomic criteria,which have their limitations.These limitations include a lack of precision for the morphological tool and cost and time for the DNA-based approach.Recently,Matrix-Assisted Laser Desorp-tion/lonization Time-Of-Flight(MALDI-TOF)mass spectrometry,a new tool used which is routinely in clinical microbi-ology,has emerged in the field of malacology for the identification of freshwater snails.This study aimed to evaluate the ability of MALDI-TOF MS to identify Biomphalaria pfeifferi and Bulinus forskali snail populations according to their geographicalorigin.Methods This study was conducted on 101 Bi.pfeifferi and 81 Bu.forskali snails collected in three distinct geo-graphical areas of Senegal(the North-East,South-East and central part of the country),and supplemented with wild and laboratory strains.Specimens which had previously been morphologically described were identified by MALDl-TOF MS[identification log score values(LSV)≥1.7],after an initial blind test using the pre-existing database.After DNA-based identification,new reference spectra of Bi.pfeiferi(n=10)and Bu.forskali(n=5)from the geographical areas were added to the MALDI-TOF spectral database.The final blind test against this updated database was per-formed to assess identification at the geographic source level.Results MALDI-TOF MS correctly identified 92.1%of 101 Bi.pfeifferi snails and 98.8%of 81 Bu.forskali snails.At the final blind test,88%of 166 specimens were correctly identified according to both their species and sampling site,with LSVs ranging from 1.74 to 2.70.The geographical source was adequately identified in 90.1%of 91 Bi.pfeifferi and 85.3%of 75 Bu.forskalii samples.Conclusions Our findings demonstrate that MALDI-TOF MS can identify and differentiate snail populations according to geographical origin.It outperforms the current DNA-based approaches in discriminating laboratory from wild strains.This inexpensive high-throughput approach is likely to further revolutionise epidemiological studies in areas which are endemic for schistosomiasis.
基金supported by the National Natural Science Foundation of China(Grant No.32372448)Guangdong Basic and Applied Basic Research Foundation,China(Grant No.2023A1515012605)+2 种基金the Science and Technology Program of Guangdong Administration for Market Regulation,China(Grant No.2023CS01)the Science and Technology Program of National General Customs Administration of China(Grant No.2022HK108)the Science and Technology Program of Shantou City,China(Grant No.STKJ2023024).
文摘Gelsemium elegans Benth alkaloids are the main components of G.elegans and can cause acute toxicosis or even death.Although several studies have reported methods for detecting G.elegans alkaloids,a high-throughput and environmental-friendly strategy for detection of multiple G.elegans alkaloids has not been realized.In this work,a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry method was developed for rapid detection of G.elegans alkaloids in human plasma and urine for diagnosis of poisoning.Multiple matrices and crys-tal spotting methods were evaluated to obtain stable and high peak intensities without“sweet spot”.We verified the methodology and obtained excellent results.The matrix effects with different dilutions were compared and good recoveries and a low relative standard deviation were obtained with a 40-fold dilution.This method could shorten the analysis time and greatly reduce the consumption of chemical solvents.Furthermore,it could be applied to quan-titative assessment of G.elegans alkaloid poisoning incidents.
