Photocatalytic water splitting for hydrogen evolution reaction(HER)has emerged as one of the most promising approaches for solar energy utilization.Porous easily functionalized metal-organic framework(MOF)represents a...Photocatalytic water splitting for hydrogen evolution reaction(HER)has emerged as one of the most promising approaches for solar energy utilization.Porous easily functionalized metal-organic framework(MOF)represents a rising crystalline material for photocatalytic application.Yet,most MOFs still face challenges like chemical instability in solution media,no photosensitization,and ambiguous active sites.Herein,thiol-dense Hf-or Zr-based porous frameworks(Hf-,Zr-TBAPy-8SH)were prepared as platforms for facile construction of HER active sites by anchoring transition metal(TM)ions as well as forming heterojunction with nanoscale semiconductor(CdS).The highest HER rate of 8.15mmol g^(-1) h^(-1) by Co(Ⅱ)-loaded Hf-based composite highlight(1)[S^(-)-Co]motifs as competent HER site,(2)match heterojunction outweighing traditional photosensitizer-mediated HER,(3)regulating electron density of metal-oxo cluster as a way to harness HER activity.This study firstly demonstrates synergy of Hf-oxo clusters,thiol functionalities and heterojunction as an easy yet controllable strategy to form integrated photocatalyst.展开更多
Epoxy resin is widely used in electronic packaging due to its exceptional performance,particularly the low-temperature curable thiol/epoxy system,which effectively minimizes thermal damage to sensitive electronic comp...Epoxy resin is widely used in electronic packaging due to its exceptional performance,particularly the low-temperature curable thiol/epoxy system,which effectively minimizes thermal damage to sensitive electronic components.However,the majority of commercial thiol curing agents contain hydrolysable ester bonds and lack rigid structures,which induces most of thiol/epoxy systems still suffering from unsatisfactory heat resistance and hygrothermal resistance,significantly hindering their application in electronic packaging.In this study,we synthesized a tetrafunctional thiol compound,bis[3-(3-sulfanylpropyl)-4-(3-sulfanylpropoxy)phenyl]sulfone(TMBPS)with rigid and ester-free structures to replace traditional commercial thiol curing agents,pentaerythritol tetra(3-mercaptopropionate)(PETMP).Compared to the PETMP/epoxy system,the TMBPS/epoxy system exhibited superior comprehensive properties.The rigid structures of bisphenol S-type tetrathiol enhanced the heat resistance and mechanical properties of TMBPS/epoxy resin cured products,outperforming those of PETMP/epoxy resin cured products.Notably,the glass transition temperature of TMBPS/epoxy resin cured products was 74.2℃which was 11.8°C higher than that of PETMP cured products.Moreover,the ester-free structure in TMBPS contributed to its enhanced resistance to chemicals and hygrothermal conditions.After undergoing 1000 h of hightemperature and high-humidity aging,the tensile strength and adhesion strength of TMBPS-cured products were 73.33 MPa and 3.39 MPa,respectively exceeding 100%and 40%of their initial values,while PETMP-cured products exhibited a complete loss of both tensile strength and adhesion strength.This study provides a strategy for obtaining thermosetting polymers that can be cured at low temperatures and exhibit excellent comprehensive properties.展开更多
Metal-organic frameworks(MOFs)attract broad interests in mercury(Hg)ion adsorption field,while unreasonable distribution of active groups commonly restricts their utilization efficiency.In this work,we constructed a n...Metal-organic frameworks(MOFs)attract broad interests in mercury(Hg)ion adsorption field,while unreasonable distribution of active groups commonly restricts their utilization efficiency.In this work,we constructed a new MOF(TYUST-6)with dense thiol-rich traps in the 1D pore wall.This accessible channel and rational distribution of thiols allow the smooth diffusion of Hg ions and thereby result in a high Langmuir adsorption capacity of 1347.6 mg/g,almost reaching the theoretical maximum(1444.3 mg/g).Adsorption equilibrium needs 10 and 30 min at the initial concentrations of 10 and 100 mg/L,respectively.Common co-existing ions and solution pH show almost negligible interferences on the adsorption,and adsorbent regeneration can be well achieved.Combining experimental characterizations and theoretical calculations,the thiol groups in the pore wall are proved to be the dominant interaction sites.Thus,this work reports a novel high-capacity adsorbent for Hg^(2+),and proposes a feasible guideline for designing effective adsorbents.展开更多
Redox dyshomeostasis is a critical factor in the initiation of numerous diseases,making the accurate evaluation of the redox status of the cellular environment an important aspect of physiological research.However,mai...Redox dyshomeostasis is a critical factor in the initiation of numerous diseases,making the accurate evaluation of the redox status of the cellular environment an important aspect of physiological research.However,maintaining redox homeostasis relies on a complex and dynamic physiological system involving multiple substrate-enzyme interactions,so its accurately detection remains a challenge.With this research,we developed an activable fiuorescence switching platform by incorporating different conjugate acceptors to a fiuorophore using ester bonds and resulting in fiuorescence quenching due to donor-excited photo-induced electron transfer(d-Pe T),which was confirmed through density functional theory calculations.The reaction-based probe was deployed for recognizing all major intracellular reducing sulfur species(RSS),including H_(2)S,cysteine(Cys),homocysteine(Hcy),glutathione(GSH),and protein free thiols.The quenched fiuorescence was significantly recovered by RSS,through releasing the fiuorophore and diminishing the d-Pe T effect.Furthermore,the fiuorescent probe was used for the sensing and imaging RSS in living cells,demonstrating good cell-permeability,low cytotoxicity,and negative correlation with reactive oxygen species content,enabling the evaluating of global thiols redox state in Hep G2 cellular lines during ferroptosis processes.展开更多
Understanding the based-on drug or drug conjugates to reach the beneficial optimally recognized by the immune system requires multidisciplinary approaches and detailed of albumin as the key circulating a transporting/...Understanding the based-on drug or drug conjugates to reach the beneficial optimally recognized by the immune system requires multidisciplinary approaches and detailed of albumin as the key circulating a transporting/transmission and antioxidant protein of blood drug interaction. Albumin, in reduced form (mercaptoalbumin, HMA), with antioxidant ability and alterations/deteriorations in the redox status of human serum albumin (HSA) under oxidative stress formation in infection diseases and its complications strongly modifies albumin antioxidant capacity. The aim of this study was the investigation of carbonyl/oxidative stress and pseudo-esterase activity of mercaptolbumin and oxidized HSA models. HSA (P. pastoris) purchased from MedChemExpress (USA) was used for study to model oxidative stress, HSA in reduced (intact) form was treated with H2O2, tert-butylhydroperoxide (t-BHP) and chloramine T (CT). The content of HSA-bound carbonyl groups decreased in under treatment with t-BPH- and CT-reduced HSA and more less extent in case of H2O2-treated. Fatty acid-free HSA and mercaptoalbumin (HMA) advanced oxidation protein products (AOPP) concentrations were significantly lower than in H2O2 loading reduced HSA by 123% and 235%, respectively. The total thiols level was lower in HMA + CT compared to reduced HMA by 51% and even increased after treatment of HMA with H2O2. Pseudo-esterase activity of HMA maintains >65% in the presence of hydroperoxide and occurs pronounced loss in the presence of chloramine T. Hydrogen peroxide at physiological concentration about 10 μM occurs less damage of reduced from of HSA then t-BPH and CT, and unlike t-BPH and CT, without significantly changes in pseudo-esterase activities.展开更多
Thiols play vital roles in cellular metabolism knowledge of which may be important in the design of future anticancer drugs. Previous work on the composition of the thiols present in human cancer cell lines has shown ...Thiols play vital roles in cellular metabolism knowledge of which may be important in the design of future anticancer drugs. Previous work on the composition of the thiols present in human cancer cell lines has shown the presence of an unknown low molecular weight species, deemed to be a “Conthiol”, which could be important in this respect. This was prepared and isolated from a human prostate cancer cell line (LNCaP) in the form of an adduct of 2-mercuri-4-nitrophenol;it accounts for 56.5% of the total cellular thiols present in this cell line. Initial LC-MS analysis of this adduct had indicated that the possible molecular weight of the thiol was in the region of 467 daltons. In further analytical studies to identify the thiol, attempts were made to release it from the adduct by passage through a Thiopropyl Sepharose6B column. LC-MS analysis of the column eluate revealed two components yielding negative ion fragments of 427 m/z and 449 m/z. Only the former component contained thiol, indicating that a breakdown and/or possible rearrangement of the Conthiol had occurred. Further investigations of the column thiol eluate using ICP-MS analysis showed that the sulfur content agreed with the spectrophotometric analysis result (Ellman assay) and that the molecule did not contain phosphate. Amino acid analyses of the eluate were negative. In an attempt to prevent the breakdown of the thiol released by the Thiopropyl Sepharose 6B column, the adduct was treated with 5% v/v bromine water prior to applying to the column. In this instance the thiol containing eluate obtained from the column was treated with an equimolar quantity of mercuric chloride forming a fresh adduct, RS-Hg-SR. LC-MS analysis of this mercurial adduct detected a negative ion fragment of 782 m/z which on further ionization gave a ladder like pattern showing loss of mass units of 58 in each rung. This would seem to suggest the presence of a repeat polymer like structure containing 5 monomers, which, plus the thiol atom, gives a possible formula weight of 322;probably revealing only a part of the unknown Conthiol molecule whose properties and formula weight do not correlate with any known cellular thiol. Further analysis of the thiol released from the adduct on the Thiopropyl Sepharose 6B column by Infra-red (FTIR) provided little information except to confirm the presence of the thiol group and C=O stretch bands together with the possibility of a lactam ring at 1651 and 1634 cm·s<sup>-</sup><sup>1</sup>.展开更多
The vicinal dithiol motif is widely present in proteins, and is critical for proteins’ structures and functions.In recent years, a variety of fluorescent probes with high specificity and outstanding optical propertie...The vicinal dithiol motif is widely present in proteins, and is critical for proteins’ structures and functions.In recent years, a variety of fluorescent probes with high specificity and outstanding optical properties for sensing protein vicinal dithiols have been developed. In this review, we summarized the fluorescent probes of protein vicinal dithiols in literature. These probes are classified into four types based on their acceptor sites, i.e., biarsenical probes, monoarsenical probes, dimaleimide probes and diacrylate probes.Through analyzing the properties of different probes, we expect that this review would help readers further understand the structural factors of these probes and provide the design strategy for novel fluorescent probes with improved properties.展开更多
The thiol components of the nonhistone proteins prepared from isolated nuclei from rat liver, regenerating liver and hepatoma 223 cells have been investigated after reaction with radio labelled N-ethylmaleimide and 5-...The thiol components of the nonhistone proteins prepared from isolated nuclei from rat liver, regenerating liver and hepatoma 223 cells have been investigated after reaction with radio labelled N-ethylmaleimide and 5-5’-dithiobis-(2-nitrobenzoic acid) (DTNB). The labelled adducts formed were examined by isoelectric focusing analysis in polyacrylamide gel and the distribution of the radiolabels within sliced portions of the gels determined. In the case of the 14C labelled NEM adduct the label was found to be spread amongst numerous protein components within the gel however, in the case of the 35S labelled DTNB adducts, only a small proportion of the label was found in the protein material which was retained in the acidic isoelectric point (pI) region of the gel. The bulk of the 35S labelled adduct (56% - 60%) was found to have migrated into the anode solution (10 mM phosphoric acid). This could be adsorbed onto a hydrophobic resin (XAD2) resin and eluted with methanol. Gel filtration chromatographic analysis of this adduct material on BioGel P2, (exclusion limit 1500 daltons) showed low molecular weight components to be present. Slightly different patterns were obtained for these nuclei, each containing several 35S components with molecular weights greater than the Ellman reagent itself. These 35S labelled thiol components did not contain any protein, peptide or amino acid components indicating strongly that a novel species of thiols could be present in these nuclei bound within the non-histone protein matrices.展开更多
The low molecular weight thiols present in the deproteinized extract of a prostate cancer cell line (LNCaP-FGC) were analysed after derivatization with the Ellman reagent (ESSE). The mixed disulphides formed (RSSE) we...The low molecular weight thiols present in the deproteinized extract of a prostate cancer cell line (LNCaP-FGC) were analysed after derivatization with the Ellman reagent (ESSE). The mixed disulphides formed (RSSE) were fractionated, characterized and quantified by liquid chromatography on a C-18 column using UV detection. This revealed the presence, in femtomoles per cell, of glutathione (8.30 ± 0.73), cysteine (2.71 ± 0.04) and cysteinylglycine (0.83 ± 0.10), accounting for the bulk of the thiol present. Further analysis of the cell extracts using a novel and sensitive mass spectrometry technique allowed the detection of low level of an additional derivative which was identified as cysteinylglycerate using NMRspectroscopy.展开更多
Background:Cholangiocarcinoma(CCA)is a cancer type that builds in the bile ducts that carry digestive fluid,bile.These ducts connect the liver to the gallbladder and the small intestine.The disease is often diagnosed ...Background:Cholangiocarcinoma(CCA)is a cancer type that builds in the bile ducts that carry digestive fluid,bile.These ducts connect the liver to the gallbladder and the small intestine.The disease is often diagnosed at an advanced stage,resulting in a low 5-year survival rate.This study aims to evaluate the concentrations of serum thiol/disulfide in CCA patients and healthy volunteers and investigate the association between oxidative activity and clinical and pathological characteristics in CCA patients.By examining the relationship between reduced thiol/disulfide measures and tumorigenesis of the disease,we can potentially identify an unfavourable prognosis in CCA patients.Methods:To assess the status of thiol/disulfide in the blood of Cholangiocarcinoma patients using a novel automated homeostasis assay,we recruited 55 individuals for this study(CCA patients,n=27;healthy volunteers,n=28).We measured the levels of serum total thiol(TT)(–SH+–S-S–),native thiol(NT)(–SH),and disulfide(DD)(–S-S–)in both the CCA group and the control group.Additionally,we calculated the ratio of thiol/disulfide(–SH/–S-S–).Results:We explored the relationship between oxidative activity and clinical and pathological characteristics in CCA patients.The study found no significant differences in age and sex between CCA patients and controls.NT and TT levels were higher in the control group compared to the CCA group.However,the disulfide level did not significantly differ between the two groups.Pearson's correlation matrix analysis revealed positive correlations between TT and NT levels and negative correlations between NT/TT%,DD level,and DD/TT%.Conclusion:Our findings suggest a statistical difference in serum thiol/disulfide parameters.As a marker of total oxidant status,thiol and disulfide levels have decreased in patients with CCA.However,no correlation was found between the tumour markers CEA and CA19-9 and thiol levels.A decrease in blood thiol and disulfide concentrations or the ratio of thiol to disulfide may indicate an increase in oxidative stress and decreased antioxidant capacity.As an indication of the prognosis of cholangiocarcinoma disease in the early period,it may be used to determine the effectiveness of medical interventions.The NT/TT%,disulfide/native thiol percentage,and DD/TT%ratios did not significantly change between the groups.Therefore,measuring serum thiol levels could be a helpful marker for assessing prognosis in the early stages of CCA.Nevertheless,further studies must validate these results and investigate the underlying mechanisms.展开更多
Sulfur containing ion imprinted polymers(S-IIPs) were applied for the uptake of Hg(Ⅱ) from aqueous solution. Cysteamine which was used as the ligand for Hg(Ⅱ) complexation, was grafted along the epichlorohydrin cros...Sulfur containing ion imprinted polymers(S-IIPs) were applied for the uptake of Hg(Ⅱ) from aqueous solution. Cysteamine which was used as the ligand for Hg(Ⅱ) complexation, was grafted along the epichlorohydrin crosslinked carboxylated carboxymethyl cellulose polymer chain through an amide reaction. The adsorption ability of S-IIPs towards Hg(Ⅱ)was investigated by kinetic and isotherm models, which, corresponding, showed that the adsorption process followed a pseudo-second-order, fitted well with the Langmuir isotherm with a maximum adsorption capacity of 80 mg/g. Moreover, thermodynamic studies indicated an endothermic and spontaneous reaction with the tendency of an enhanced randomness at the surface of the S-IIPs with temperature increases. S-IIPs indicated a high degree of selectivity towards Hg(Ⅱ) in the presence of Cu^(2+), Zn^(2+), Co^(2+), Pb^(2+)and Cd^(2+).Furthermore, the efficiency of S-IIPs was also evaluated against real samples showing86.78%, 91.88%, and 99.10% recovery for Hg(Ⅱ) wastewater, ground water and tap water,respectively. In this study, the adsorbent was successfully regenerated for five cycles, which allows for their reuse without significant loss of initial adsorption capability.展开更多
Oxidative stress, the imbalance between the production of reactive oxygen species （ROS） and antioxidant activity is a major culprit of male infertility. Peroxiredoxins （PRDXs） are major antioxidant enzymes of mamm...Oxidative stress, the imbalance between the production of reactive oxygen species （ROS） and antioxidant activity is a major culprit of male infertility. Peroxiredoxins （PRDXs） are major antioxidant enzymes of mammalian spermatozoa and are thiol oxidized and inactivated by ROS in a dose-dependent manner. Their deficiency and/or inactivation have been associated with men infertility. The aim of this study was to elucidate the impact of oxidative stress, generated by the in vivo tert-butyl hydroperoxide （tert-BHP） treatment on rat epididymal spermatozoa during their maturation process. Adult Sprague-Dawley males were treated with 300 -moles tert-BHP/kg or saline （control） per day intraperitoneal for 15 days. Lipid peroxidation （2-thibarbituric acid reactive substances assay）, total amount and thiol oxidation of PRDXs along with the total amount of superoxide dismutase （SOD）, motility and DNA oxidation （8-hydroxy-deoxyguanosine） were determined in epididymal spermatozoa. Total amount of PRDXs and catalase and thiol oxidation of PRDXs were determined in caput and cauda epididymis. While animals were not affected by treatment, their epididymal spermatozoa have decreased motility, increased levels of DNA oxidation and lipid peroxidation along with increased PRDXs （and not SOD） amounts. Moreover, sperm PRDXs were highly thiol oxidized. There was a differential regulation in the expression of PRDX1 and PRDX6 in the epididymis that suggests a segment-specific role for PRDXs. In conclusion, PRDXs are increased in epididymal spermatozoa in an attempt to fight against the oxidative stress generated by tert-BHP in the epididymis. These findings highlight the role of PRDXs in the protection of sperm function and DNA integrity during epididymal maturation.展开更多
A method for the synthesis of diaryl sulfides from aryl halides in polyethylene glycol was reported.Inodorous Na2S2O3·5H2O,which is readily available as a stable salt,is an effective source of sulfur in the prese...A method for the synthesis of diaryl sulfides from aryl halides in polyethylene glycol was reported.Inodorous Na2S2O3·5H2O,which is readily available as a stable salt,is an effective source of sulfur in the presence of Cu I as catalyst.展开更多
Fe（NO3）3-9H2O/Fe（HSO4）3 was used as an efficient reagent system for the oxidation of alcohols to their corresponding carbonyl compounds. All reactions were performed in the absence of solvent in good to high yield...Fe（NO3）3-9H2O/Fe（HSO4）3 was used as an efficient reagent system for the oxidation of alcohols to their corresponding carbonyl compounds. All reactions were performed in the absence of solvent in good to high yields. Under the same reaction conditions, thiols and sulfides were also converted to their corresponding disulfides and sulfoxides, respectively. 2007 Farhad Shirini. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
Several water-soluble calix[4]arenes were synthesized via radical addition reaction between thiols and alkenes under UV lamp irradiation（λ= 365 nm） in good yields.The structures of these compounds synthesized herei...Several water-soluble calix[4]arenes were synthesized via radical addition reaction between thiols and alkenes under UV lamp irradiation（λ= 365 nm） in good yields.The structures of these compounds synthesized herein were fully confirmed by 1 H NMR.ES1-MS and elemental analysis.展开更多
The emulsion polymerization of highly shear-stable copolymer dispersions of methyl methacrylate and butyl acrylate were carried out using poly （vinyl alcohol） with a thiol end group （PVA-SH） as protective colloid....The emulsion polymerization of highly shear-stable copolymer dispersions of methyl methacrylate and butyl acrylate were carried out using poly （vinyl alcohol） with a thiol end group （PVA-SH） as protective colloid. The dispersions can be transformed into corresponding redispersible powder via a spray dryingcooling process. On-line FT-IR monitoring shows that grafting polymer of PVA-g-PMMA was formed mainly at the stage-1 of the emulsion polymerization. TEM images show, the PVA-SH shell was fragmentary when adding SDS at initial stage and integrated when adding at particle growing or final stage. The particle size turns to be smaller when delayed adding SDS surfactant. Triethanolamine, a co-regulator of PVA-SH, controlled the M to 50 000-70 000 and reduced the PDI to 1.5-1.7. The acrylic dispersions with 0.8wt%-1.5wt% PVA-SH1 can be spray-dried into super dispersible polymer powder （SDPP）, which can easily disperse in water and form recon- stituted dispersions with an average particle size smaller than 1 micron.展开更多
An efficient and convenient tert-butyl nitrite-catalyzed selective aerobic oxidation of thiols has been developed. Under the optimal reaction conditions, a number of thiol derivatives including aromatic thiols, hetero...An efficient and convenient tert-butyl nitrite-catalyzed selective aerobic oxidation of thiols has been developed. Under the optimal reaction conditions, a number of thiol derivatives including aromatic thiols, heteroaromatic thiols and aliphatic thiols can be converted into their corresponding disulfides in good to excellent yields.展开更多
A Michael addition is usually taken as a base-catalysed reaction. However, our synthesized 2-（quinolin-2-ylmethylene） malonic acid （QMA） as a Michael-type thiol fluorescent probe is acid-active in its sensing reac...A Michael addition is usually taken as a base-catalysed reaction. However, our synthesized 2-（quinolin-2-ylmethylene） malonic acid （QMA） as a Michael-type thiol fluorescent probe is acid-active in its sensing reaction. In this work, based on theoretic calculation and experimental study on 7-hydroxy-2-（quinolin-2-ylmethylene） malonic acid, we demonstrated that QMA as a Michael acceptor is acid-activatable, i.e., it works only in solutions at pH〈7, and the lower the pH of solutions is, the higher reactivity QMA has. In alkaline solution, the malonate QMA[-2H＋]2- cannot react with both RSand RSH. In contrast, 2-（quinolin-2- ylmethylene） malonic ester （QME）, the ester of QMA, reveal a contrary pH effect on its sensing reaction, that is, it can sense thiols in alkaline solutions but not in acidic solutions, like a normal base-catalysed Michael addition. The values of activation enthalpies from theoretic calculation support the above sensing behavior of two probes under different pH conditions. In acidic solutions, the protonated QMA is more highly reactive towards electrophilic attack over its other ionized states in neutral and alkaline solutions, and so can react with lowly reactive RSH. In contrast, there is a big energy barrier in the interaction of QME with RSH （acidic solutions）, and the reaction of QME with the highly reactive nucleophile RS- is a low activation energy process （in alkaline solutions）. Theoretic calculation reveals that the sensing reaction of QMA undergoes a 1,4-addition process with neutral thiols （RSH）, and a 1,2-addition pathway for the sensing reaction of QME with RS-. Therefore, the sensing reaction of QMA is an acid-catalysed Michael addition via a 1,4-addition, and a normal base-catalysed Michael addition via a 1,2-addition.展开更多
基金supported by the National Natural Science Foundation of China(Nos.22371054,22301045)the Foundation of Basic and Applied Basic Research of Guangdong Province(Nos.2020B1515120024,2024A1515012801)Science and Technology Planning Project of Guangdong Province(Nos.2021A0505030066,2023A0505050164).
文摘Photocatalytic water splitting for hydrogen evolution reaction(HER)has emerged as one of the most promising approaches for solar energy utilization.Porous easily functionalized metal-organic framework(MOF)represents a rising crystalline material for photocatalytic application.Yet,most MOFs still face challenges like chemical instability in solution media,no photosensitization,and ambiguous active sites.Herein,thiol-dense Hf-or Zr-based porous frameworks(Hf-,Zr-TBAPy-8SH)were prepared as platforms for facile construction of HER active sites by anchoring transition metal(TM)ions as well as forming heterojunction with nanoscale semiconductor(CdS).The highest HER rate of 8.15mmol g^(-1) h^(-1) by Co(Ⅱ)-loaded Hf-based composite highlight(1)[S^(-)-Co]motifs as competent HER site,(2)match heterojunction outweighing traditional photosensitizer-mediated HER,(3)regulating electron density of metal-oxo cluster as a way to harness HER activity.This study firstly demonstrates synergy of Hf-oxo clusters,thiol functionalities and heterojunction as an easy yet controllable strategy to form integrated photocatalyst.
基金the support of the Science and Technology Commission of Shanghai Municipality(STCSM,No.20dz1203600)the Experimental Center of Materials Science and Engineering in Tongji University。
文摘Epoxy resin is widely used in electronic packaging due to its exceptional performance,particularly the low-temperature curable thiol/epoxy system,which effectively minimizes thermal damage to sensitive electronic components.However,the majority of commercial thiol curing agents contain hydrolysable ester bonds and lack rigid structures,which induces most of thiol/epoxy systems still suffering from unsatisfactory heat resistance and hygrothermal resistance,significantly hindering their application in electronic packaging.In this study,we synthesized a tetrafunctional thiol compound,bis[3-(3-sulfanylpropyl)-4-(3-sulfanylpropoxy)phenyl]sulfone(TMBPS)with rigid and ester-free structures to replace traditional commercial thiol curing agents,pentaerythritol tetra(3-mercaptopropionate)(PETMP).Compared to the PETMP/epoxy system,the TMBPS/epoxy system exhibited superior comprehensive properties.The rigid structures of bisphenol S-type tetrathiol enhanced the heat resistance and mechanical properties of TMBPS/epoxy resin cured products,outperforming those of PETMP/epoxy resin cured products.Notably,the glass transition temperature of TMBPS/epoxy resin cured products was 74.2℃which was 11.8°C higher than that of PETMP cured products.Moreover,the ester-free structure in TMBPS contributed to its enhanced resistance to chemicals and hygrothermal conditions.After undergoing 1000 h of hightemperature and high-humidity aging,the tensile strength and adhesion strength of TMBPS-cured products were 73.33 MPa and 3.39 MPa,respectively exceeding 100%and 40%of their initial values,while PETMP-cured products exhibited a complete loss of both tensile strength and adhesion strength.This study provides a strategy for obtaining thermosetting polymers that can be cured at low temperatures and exhibit excellent comprehensive properties.
基金supported by the National Natural Science Foundation of China(No.22208230)Fundamental Research Program of Shanxi Province(No.202103021223281)。
文摘Metal-organic frameworks(MOFs)attract broad interests in mercury(Hg)ion adsorption field,while unreasonable distribution of active groups commonly restricts their utilization efficiency.In this work,we constructed a new MOF(TYUST-6)with dense thiol-rich traps in the 1D pore wall.This accessible channel and rational distribution of thiols allow the smooth diffusion of Hg ions and thereby result in a high Langmuir adsorption capacity of 1347.6 mg/g,almost reaching the theoretical maximum(1444.3 mg/g).Adsorption equilibrium needs 10 and 30 min at the initial concentrations of 10 and 100 mg/L,respectively.Common co-existing ions and solution pH show almost negligible interferences on the adsorption,and adsorbent regeneration can be well achieved.Combining experimental characterizations and theoretical calculations,the thiol groups in the pore wall are proved to be the dominant interaction sites.Thus,this work reports a novel high-capacity adsorbent for Hg^(2+),and proposes a feasible guideline for designing effective adsorbents.
基金the National Natural Science Foundation of China(Nos.21907080,22278330)Youth Innovative Team(No.xtr052022012)+3 种基金Fundamental Research Funds for the Central University(No.xzy012023010)from Xi’an Jiaotong Universitysupported by Natural Science Basic Research Program of Shaanxi(No.2023-JC-QN-0246)China/Shaanxi Postdoctoral Science Foundation(Nos.2023M732811,2023BSHEDZZ20)the University of Bath and the Open Research Fund of the School of Chemistry and Chemical Engineering,Henan Normal University(No.2020ZD01)for support。
文摘Redox dyshomeostasis is a critical factor in the initiation of numerous diseases,making the accurate evaluation of the redox status of the cellular environment an important aspect of physiological research.However,maintaining redox homeostasis relies on a complex and dynamic physiological system involving multiple substrate-enzyme interactions,so its accurately detection remains a challenge.With this research,we developed an activable fiuorescence switching platform by incorporating different conjugate acceptors to a fiuorophore using ester bonds and resulting in fiuorescence quenching due to donor-excited photo-induced electron transfer(d-Pe T),which was confirmed through density functional theory calculations.The reaction-based probe was deployed for recognizing all major intracellular reducing sulfur species(RSS),including H_(2)S,cysteine(Cys),homocysteine(Hcy),glutathione(GSH),and protein free thiols.The quenched fiuorescence was significantly recovered by RSS,through releasing the fiuorophore and diminishing the d-Pe T effect.Furthermore,the fiuorescent probe was used for the sensing and imaging RSS in living cells,demonstrating good cell-permeability,low cytotoxicity,and negative correlation with reactive oxygen species content,enabling the evaluating of global thiols redox state in Hep G2 cellular lines during ferroptosis processes.
文摘Understanding the based-on drug or drug conjugates to reach the beneficial optimally recognized by the immune system requires multidisciplinary approaches and detailed of albumin as the key circulating a transporting/transmission and antioxidant protein of blood drug interaction. Albumin, in reduced form (mercaptoalbumin, HMA), with antioxidant ability and alterations/deteriorations in the redox status of human serum albumin (HSA) under oxidative stress formation in infection diseases and its complications strongly modifies albumin antioxidant capacity. The aim of this study was the investigation of carbonyl/oxidative stress and pseudo-esterase activity of mercaptolbumin and oxidized HSA models. HSA (P. pastoris) purchased from MedChemExpress (USA) was used for study to model oxidative stress, HSA in reduced (intact) form was treated with H2O2, tert-butylhydroperoxide (t-BHP) and chloramine T (CT). The content of HSA-bound carbonyl groups decreased in under treatment with t-BPH- and CT-reduced HSA and more less extent in case of H2O2-treated. Fatty acid-free HSA and mercaptoalbumin (HMA) advanced oxidation protein products (AOPP) concentrations were significantly lower than in H2O2 loading reduced HSA by 123% and 235%, respectively. The total thiols level was lower in HMA + CT compared to reduced HMA by 51% and even increased after treatment of HMA with H2O2. Pseudo-esterase activity of HMA maintains >65% in the presence of hydroperoxide and occurs pronounced loss in the presence of chloramine T. Hydrogen peroxide at physiological concentration about 10 μM occurs less damage of reduced from of HSA then t-BPH and CT, and unlike t-BPH and CT, without significantly changes in pseudo-esterase activities.
文摘Thiols play vital roles in cellular metabolism knowledge of which may be important in the design of future anticancer drugs. Previous work on the composition of the thiols present in human cancer cell lines has shown the presence of an unknown low molecular weight species, deemed to be a “Conthiol”, which could be important in this respect. This was prepared and isolated from a human prostate cancer cell line (LNCaP) in the form of an adduct of 2-mercuri-4-nitrophenol;it accounts for 56.5% of the total cellular thiols present in this cell line. Initial LC-MS analysis of this adduct had indicated that the possible molecular weight of the thiol was in the region of 467 daltons. In further analytical studies to identify the thiol, attempts were made to release it from the adduct by passage through a Thiopropyl Sepharose6B column. LC-MS analysis of the column eluate revealed two components yielding negative ion fragments of 427 m/z and 449 m/z. Only the former component contained thiol, indicating that a breakdown and/or possible rearrangement of the Conthiol had occurred. Further investigations of the column thiol eluate using ICP-MS analysis showed that the sulfur content agreed with the spectrophotometric analysis result (Ellman assay) and that the molecule did not contain phosphate. Amino acid analyses of the eluate were negative. In an attempt to prevent the breakdown of the thiol released by the Thiopropyl Sepharose 6B column, the adduct was treated with 5% v/v bromine water prior to applying to the column. In this instance the thiol containing eluate obtained from the column was treated with an equimolar quantity of mercuric chloride forming a fresh adduct, RS-Hg-SR. LC-MS analysis of this mercurial adduct detected a negative ion fragment of 782 m/z which on further ionization gave a ladder like pattern showing loss of mass units of 58 in each rung. This would seem to suggest the presence of a repeat polymer like structure containing 5 monomers, which, plus the thiol atom, gives a possible formula weight of 322;probably revealing only a part of the unknown Conthiol molecule whose properties and formula weight do not correlate with any known cellular thiol. Further analysis of the thiol released from the adduct on the Thiopropyl Sepharose 6B column by Infra-red (FTIR) provided little information except to confirm the presence of the thiol group and C=O stretch bands together with the possibility of a lactam ring at 1651 and 1634 cm·s<sup>-</sup><sup>1</sup>.
基金financial supports from the National Natural Science Foundation of China (Nos. 21572093 & 21778028)the 111 Project
文摘The vicinal dithiol motif is widely present in proteins, and is critical for proteins’ structures and functions.In recent years, a variety of fluorescent probes with high specificity and outstanding optical properties for sensing protein vicinal dithiols have been developed. In this review, we summarized the fluorescent probes of protein vicinal dithiols in literature. These probes are classified into four types based on their acceptor sites, i.e., biarsenical probes, monoarsenical probes, dimaleimide probes and diacrylate probes.Through analyzing the properties of different probes, we expect that this review would help readers further understand the structural factors of these probes and provide the design strategy for novel fluorescent probes with improved properties.
文摘The thiol components of the nonhistone proteins prepared from isolated nuclei from rat liver, regenerating liver and hepatoma 223 cells have been investigated after reaction with radio labelled N-ethylmaleimide and 5-5’-dithiobis-(2-nitrobenzoic acid) (DTNB). The labelled adducts formed were examined by isoelectric focusing analysis in polyacrylamide gel and the distribution of the radiolabels within sliced portions of the gels determined. In the case of the 14C labelled NEM adduct the label was found to be spread amongst numerous protein components within the gel however, in the case of the 35S labelled DTNB adducts, only a small proportion of the label was found in the protein material which was retained in the acidic isoelectric point (pI) region of the gel. The bulk of the 35S labelled adduct (56% - 60%) was found to have migrated into the anode solution (10 mM phosphoric acid). This could be adsorbed onto a hydrophobic resin (XAD2) resin and eluted with methanol. Gel filtration chromatographic analysis of this adduct material on BioGel P2, (exclusion limit 1500 daltons) showed low molecular weight components to be present. Slightly different patterns were obtained for these nuclei, each containing several 35S components with molecular weights greater than the Ellman reagent itself. These 35S labelled thiol components did not contain any protein, peptide or amino acid components indicating strongly that a novel species of thiols could be present in these nuclei bound within the non-histone protein matrices.
文摘The low molecular weight thiols present in the deproteinized extract of a prostate cancer cell line (LNCaP-FGC) were analysed after derivatization with the Ellman reagent (ESSE). The mixed disulphides formed (RSSE) were fractionated, characterized and quantified by liquid chromatography on a C-18 column using UV detection. This revealed the presence, in femtomoles per cell, of glutathione (8.30 ± 0.73), cysteine (2.71 ± 0.04) and cysteinylglycine (0.83 ± 0.10), accounting for the bulk of the thiol present. Further analysis of the cell extracts using a novel and sensitive mass spectrometry technique allowed the detection of low level of an additional derivative which was identified as cysteinylglycerate using NMRspectroscopy.
文摘Background:Cholangiocarcinoma(CCA)is a cancer type that builds in the bile ducts that carry digestive fluid,bile.These ducts connect the liver to the gallbladder and the small intestine.The disease is often diagnosed at an advanced stage,resulting in a low 5-year survival rate.This study aims to evaluate the concentrations of serum thiol/disulfide in CCA patients and healthy volunteers and investigate the association between oxidative activity and clinical and pathological characteristics in CCA patients.By examining the relationship between reduced thiol/disulfide measures and tumorigenesis of the disease,we can potentially identify an unfavourable prognosis in CCA patients.Methods:To assess the status of thiol/disulfide in the blood of Cholangiocarcinoma patients using a novel automated homeostasis assay,we recruited 55 individuals for this study(CCA patients,n=27;healthy volunteers,n=28).We measured the levels of serum total thiol(TT)(–SH+–S-S–),native thiol(NT)(–SH),and disulfide(DD)(–S-S–)in both the CCA group and the control group.Additionally,we calculated the ratio of thiol/disulfide(–SH/–S-S–).Results:We explored the relationship between oxidative activity and clinical and pathological characteristics in CCA patients.The study found no significant differences in age and sex between CCA patients and controls.NT and TT levels were higher in the control group compared to the CCA group.However,the disulfide level did not significantly differ between the two groups.Pearson's correlation matrix analysis revealed positive correlations between TT and NT levels and negative correlations between NT/TT%,DD level,and DD/TT%.Conclusion:Our findings suggest a statistical difference in serum thiol/disulfide parameters.As a marker of total oxidant status,thiol and disulfide levels have decreased in patients with CCA.However,no correlation was found between the tumour markers CEA and CA19-9 and thiol levels.A decrease in blood thiol and disulfide concentrations or the ratio of thiol to disulfide may indicate an increase in oxidative stress and decreased antioxidant capacity.As an indication of the prognosis of cholangiocarcinoma disease in the early period,it may be used to determine the effectiveness of medical interventions.The NT/TT%,disulfide/native thiol percentage,and DD/TT%ratios did not significantly change between the groups.Therefore,measuring serum thiol levels could be a helpful marker for assessing prognosis in the early stages of CCA.Nevertheless,further studies must validate these results and investigate the underlying mechanisms.
基金supported in part by the National Research Foundation of South Africa(No.93205)the Water Research Commission(WRC)of South Africa for the financial support(No.K5/2387)
文摘Sulfur containing ion imprinted polymers(S-IIPs) were applied for the uptake of Hg(Ⅱ) from aqueous solution. Cysteamine which was used as the ligand for Hg(Ⅱ) complexation, was grafted along the epichlorohydrin crosslinked carboxylated carboxymethyl cellulose polymer chain through an amide reaction. The adsorption ability of S-IIPs towards Hg(Ⅱ)was investigated by kinetic and isotherm models, which, corresponding, showed that the adsorption process followed a pseudo-second-order, fitted well with the Langmuir isotherm with a maximum adsorption capacity of 80 mg/g. Moreover, thermodynamic studies indicated an endothermic and spontaneous reaction with the tendency of an enhanced randomness at the surface of the S-IIPs with temperature increases. S-IIPs indicated a high degree of selectivity towards Hg(Ⅱ) in the presence of Cu^(2+), Zn^(2+), Co^(2+), Pb^(2+)and Cd^(2+).Furthermore, the efficiency of S-IIPs was also evaluated against real samples showing86.78%, 91.88%, and 99.10% recovery for Hg(Ⅱ) wastewater, ground water and tap water,respectively. In this study, the adsorbent was successfully regenerated for five cycles, which allows for their reuse without significant loss of initial adsorption capability.
文摘Oxidative stress, the imbalance between the production of reactive oxygen species （ROS） and antioxidant activity is a major culprit of male infertility. Peroxiredoxins （PRDXs） are major antioxidant enzymes of mammalian spermatozoa and are thiol oxidized and inactivated by ROS in a dose-dependent manner. Their deficiency and/or inactivation have been associated with men infertility. The aim of this study was to elucidate the impact of oxidative stress, generated by the in vivo tert-butyl hydroperoxide （tert-BHP） treatment on rat epididymal spermatozoa during their maturation process. Adult Sprague-Dawley males were treated with 300 -moles tert-BHP/kg or saline （control） per day intraperitoneal for 15 days. Lipid peroxidation （2-thibarbituric acid reactive substances assay）, total amount and thiol oxidation of PRDXs along with the total amount of superoxide dismutase （SOD）, motility and DNA oxidation （8-hydroxy-deoxyguanosine） were determined in epididymal spermatozoa. Total amount of PRDXs and catalase and thiol oxidation of PRDXs were determined in caput and cauda epididymis. While animals were not affected by treatment, their epididymal spermatozoa have decreased motility, increased levels of DNA oxidation and lipid peroxidation along with increased PRDXs （and not SOD） amounts. Moreover, sperm PRDXs were highly thiol oxidized. There was a differential regulation in the expression of PRDX1 and PRDX6 in the epididymis that suggests a segment-specific role for PRDXs. In conclusion, PRDXs are increased in epididymal spermatozoa in an attempt to fight against the oxidative stress generated by tert-BHP in the epididymis. These findings highlight the role of PRDXs in the protection of sperm function and DNA integrity during epididymal maturation.
基金the Persian Gulf University Research Council for generous partial financial support of this study
文摘A method for the synthesis of diaryl sulfides from aryl halides in polyethylene glycol was reported.Inodorous Na2S2O3·5H2O,which is readily available as a stable salt,is an effective source of sulfur in the presence of Cu I as catalyst.
文摘Fe（NO3）3-9H2O/Fe（HSO4）3 was used as an efficient reagent system for the oxidation of alcohols to their corresponding carbonyl compounds. All reactions were performed in the absence of solvent in good to high yields. Under the same reaction conditions, thiols and sulfides were also converted to their corresponding disulfides and sulfoxides, respectively. 2007 Farhad Shirini. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
基金supported by the National Natural Science Foundation of China(Nos.21072072 and 21102051)PCSIRT(No.IRTO953)+1 种基金Program for New Century Excellent Talent in University(No.NCET-10-0428)Self-determined Research Funds of CCNU from the Colleges Basic Research and Operation of MOE (Nos.CCNU11C01002,CCNU12A01004 and CCNU12A02012)
文摘Several water-soluble calix[4]arenes were synthesized via radical addition reaction between thiols and alkenes under UV lamp irradiation（λ= 365 nm） in good yields.The structures of these compounds synthesized herein were fully confirmed by 1 H NMR.ES1-MS and elemental analysis.
文摘The emulsion polymerization of highly shear-stable copolymer dispersions of methyl methacrylate and butyl acrylate were carried out using poly （vinyl alcohol） with a thiol end group （PVA-SH） as protective colloid. The dispersions can be transformed into corresponding redispersible powder via a spray dryingcooling process. On-line FT-IR monitoring shows that grafting polymer of PVA-g-PMMA was formed mainly at the stage-1 of the emulsion polymerization. TEM images show, the PVA-SH shell was fragmentary when adding SDS at initial stage and integrated when adding at particle growing or final stage. The particle size turns to be smaller when delayed adding SDS surfactant. Triethanolamine, a co-regulator of PVA-SH, controlled the M to 50 000-70 000 and reduced the PDI to 1.5-1.7. The acrylic dispersions with 0.8wt%-1.5wt% PVA-SH1 can be spray-dried into super dispersible polymer powder （SDPP）, which can easily disperse in water and form recon- stituted dispersions with an average particle size smaller than 1 micron.
基金financially supported by the National Natural Science Foundation of China (Nos. 21376224, 21206147)
文摘An efficient and convenient tert-butyl nitrite-catalyzed selective aerobic oxidation of thiols has been developed. Under the optimal reaction conditions, a number of thiol derivatives including aromatic thiols, heteroaromatic thiols and aliphatic thiols can be converted into their corresponding disulfides in good to excellent yields.
基金This work is supported by the National Natural Science Foundation of China （No.21272224）, the Open Research Fund of State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University （No.201410）, and the Open Research Fund of Key Laboratory of Advanced Scientific Computation, Xihua University （No.szjj2013-024）.
文摘A Michael addition is usually taken as a base-catalysed reaction. However, our synthesized 2-（quinolin-2-ylmethylene） malonic acid （QMA） as a Michael-type thiol fluorescent probe is acid-active in its sensing reaction. In this work, based on theoretic calculation and experimental study on 7-hydroxy-2-（quinolin-2-ylmethylene） malonic acid, we demonstrated that QMA as a Michael acceptor is acid-activatable, i.e., it works only in solutions at pH〈7, and the lower the pH of solutions is, the higher reactivity QMA has. In alkaline solution, the malonate QMA[-2H＋]2- cannot react with both RSand RSH. In contrast, 2-（quinolin-2- ylmethylene） malonic ester （QME）, the ester of QMA, reveal a contrary pH effect on its sensing reaction, that is, it can sense thiols in alkaline solutions but not in acidic solutions, like a normal base-catalysed Michael addition. The values of activation enthalpies from theoretic calculation support the above sensing behavior of two probes under different pH conditions. In acidic solutions, the protonated QMA is more highly reactive towards electrophilic attack over its other ionized states in neutral and alkaline solutions, and so can react with lowly reactive RSH. In contrast, there is a big energy barrier in the interaction of QME with RSH （acidic solutions）, and the reaction of QME with the highly reactive nucleophile RS- is a low activation energy process （in alkaline solutions）. Theoretic calculation reveals that the sensing reaction of QMA undergoes a 1,4-addition process with neutral thiols （RSH）, and a 1,2-addition pathway for the sensing reaction of QME with RS-. Therefore, the sensing reaction of QMA is an acid-catalysed Michael addition via a 1,4-addition, and a normal base-catalysed Michael addition via a 1,2-addition.
