An assay was described for measures of adducts of styrene oxide(SO)with molecules of hemoglobin(Hb)which have been modified at residues containing either carboxylic acid or sulfhydryl groups.The method employs two ste...An assay was described for measures of adducts of styrene oxide(SO)with molecules of hemoglobin(Hb)which have been modified at residues containing either carboxylic acid or sulfhydryl groups.The method employs two steps.In the first,SO carboxylic acid adducts are hydrolyzed in basic medium to liberate styrene glycol(SG).Then,the remaining residues are reacted with a reductive catalyst(Raney nickel)to liberate the two positional isomers of SO cysteine adducts,i.e.,1 phenylethanol(1 PE)and 2 phenylethanol(2 PE).The liberated products are derivatized with pentafluorobenzoyl chloride and measured by GC NICI MS.The assay was evaluated with SO adducts of Hb which had been produced in the blood of Sprague Dawley rats following(a)in vitro modification(0-300m mol/L SO)or(b)i.p administration of either SO(0-1 mmol/kg)or styrene(0-3 mmol/kg).Levels of each of the three analytes(SG,1 PE,and 2 PE)increased with dose in hemoglobin.The ratios of cysteine adducts to carboxylic acid adducts varied significantly among experiments.Ratios of 2 PE to 1 PE were much more consistent(2 PE/1 PE=6.9(SE=1.5))suggesting that binding of SO to cysteine residues of blood proteins is greatly preferred at theαposition rather than theβposition both in vitro and in vivo.The lowest detectable adduct concentration,using 10 mg of protein,was 8 pmol/g protein for SG,5 pmol/g protein for 1 PE,and 0.6 pmol/g protein for 2 PE.No significant change of adduct level was found during storage of proteins at-80℃for 1 year.展开更多
A photoactive polyoxometalate-based metal-organic framework (POMOF),NiW-DPNDI,was synthesized by combination of Ni(Ⅱ) ions,[ZnW_(12)O_(40)]^(6–)anions,and N,N’-bis(4-pyridylmethyl)naphthalene diimide(DPNDI) molecul...A photoactive polyoxometalate-based metal-organic framework (POMOF),NiW-DPNDI,was synthesized by combination of Ni(Ⅱ) ions,[ZnW_(12)O_(40)]^(6–)anions,and N,N’-bis(4-pyridylmethyl)naphthalene diimide(DPNDI) molecules into one single framework.Ni W-DPNDI displays a three-dimensional structure by the strong anion···π interactions between the trapped[ZnW_(12)O_(40)]^(6–)anions and the electron-deficient naphthalenic ring centroids and theπ-πstacking interactions between DPNDI moieties.Ni W-DPNDI displayed a highly efficient hole-electron separation and ordered electron transfer under irradiation,thus ensuing its excellent photocatalysis in oxidation of styrene to produce benzaldehyde.In addition,it gave a high efficiency for styrene oxide under thermocatalytic conditions.Because the carbonic anhydrase (CA)-mimicking Ni sites and the negative electron-enriched[ZnW_(12)O_(40)]^(6–)anions are well aligned in the pores,it can promote the cycloaddition of CO_(2) with epoxides under mild conditions.展开更多
La-doped and La-B-doped KIT-6 mesoporous materials were prepared by direct hydrothermal synthesis with pH-adjusting method and characterized by X-ray diffractometer(XRD),nitrogen sorption,FT-IR,UV-Vis,X-ray photoelect...La-doped and La-B-doped KIT-6 mesoporous materials were prepared by direct hydrothermal synthesis with pH-adjusting method and characterized by X-ray diffractometer(XRD),nitrogen sorption,FT-IR,UV-Vis,X-ray photoelectron spectroscopy(XPS) and ICP-AES.The catalytic performance for the oxidation of styrene by hydrogen peroxide,tert-butyl hydroperoxide or oxygen was investigated.The results showed that the introduction of heteroatoms did not destroy the mesostructure of KIT-6 with cubic Ia3d space group.La or ...展开更多
Metal foils for Raman scattering were prepared by HNO_3 etching method. These foils werefound to exhibit a strong SERS effect and excellent thermal stability. SERS spectra of cystaminehave been taken to illustrate the...Metal foils for Raman scattering were prepared by HNO_3 etching method. These foils werefound to exhibit a strong SERS effect and excellent thermal stability. SERS spectra of cystaminehave been taken to illustrate the usefulness of this sample preparation method in the studies ofchemisorption. The ring opening reactions of an epoxy compound have been observed on the topof chemisorbed cystamine on silver foils.展开更多
Amorphous nanomaterials with long-range disordered structures could possess distinct properties and promising applications,especially in catalysis,as compared with their conventional crystalline counterparts.It is imp...Amorphous nanomaterials with long-range disordered structures could possess distinct properties and promising applications,especially in catalysis,as compared with their conventional crystalline counterparts.It is imperative to achieve the controlled preparation of amorphous noble metal-based nanomaterials for the exploration of their phase-dependent applications.Here,we report a facile wet-chemical reduction strategy to synthesize various amorphous multimetallic Pd-based nanomaterials,including PdRu,PdRh,and PdRuRh.The phase-dependent catalytic performances of distinct Pd-based nanomaterials towards diverse catalytic applications have been demonstrated.Specifically,the usage of PdRu nanocatalysts with amorphous and crystalline face-centered cubic(fcc)phases can efficiently switch the ring-opening route of styrene oxide to obtain different products with high selectivity through alcoholysis reaction and hydrogenation reaction,respectively.Moreover,when used as an electrocatalyst for hydrogen evolution reaction(HER),the synthesized amorphous PdRh nanocatalyst exhibits low overpotential and high turnover frequency values,outperforming its crystalline fcc counterpart and most of the reported Pd-based HER electrocatalysts.展开更多
Toxicity assessment is a major problem in pharmaceutical candidates and industry chemicals development.However,due to the lack of practical analytical methods for DNA adduct analysis,the safety evaluation of drug and ...Toxicity assessment is a major problem in pharmaceutical candidates and industry chemicals development.However,due to the lack of practical analytical methods for DNA adduct analysis,the safety evaluation of drug and industry chemicals was severely limited.Here,we develop a DNAzyme-based method to detect DNA adduct damage for toxicity assessment of drugs and chemicals.Among 18 structural variants of G4 DNAzyme,EA2 DNAzyme exhibits an obvious DNA damaging effect of styrene oxide(SO)due to its unstable structure.The covalent binding of SO to DNAzyme disrupts the Hoogsteen hydrogen bonding sites of G-plane guanines and affects the formation of the G4 quadruplex.DNA damage chemicals reduce the peroxidase activity of the G4 DNAzyme to monitor the DNA adduct damage by disrupting the structural integrity of the G4 DNAzyme.Our method for genotoxic assessment of pharmaceutical candidates and industrial chemicals can elucidate the complex chemical pathways leading to toxicity,predict toxic effects of chemicals,and evaluate possible risks to human health.展开更多
文摘An assay was described for measures of adducts of styrene oxide(SO)with molecules of hemoglobin(Hb)which have been modified at residues containing either carboxylic acid or sulfhydryl groups.The method employs two steps.In the first,SO carboxylic acid adducts are hydrolyzed in basic medium to liberate styrene glycol(SG).Then,the remaining residues are reacted with a reductive catalyst(Raney nickel)to liberate the two positional isomers of SO cysteine adducts,i.e.,1 phenylethanol(1 PE)and 2 phenylethanol(2 PE).The liberated products are derivatized with pentafluorobenzoyl chloride and measured by GC NICI MS.The assay was evaluated with SO adducts of Hb which had been produced in the blood of Sprague Dawley rats following(a)in vitro modification(0-300m mol/L SO)or(b)i.p administration of either SO(0-1 mmol/kg)or styrene(0-3 mmol/kg).Levels of each of the three analytes(SG,1 PE,and 2 PE)increased with dose in hemoglobin.The ratios of cysteine adducts to carboxylic acid adducts varied significantly among experiments.Ratios of 2 PE to 1 PE were much more consistent(2 PE/1 PE=6.9(SE=1.5))suggesting that binding of SO to cysteine residues of blood proteins is greatly preferred at theαposition rather than theβposition both in vitro and in vivo.The lowest detectable adduct concentration,using 10 mg of protein,was 8 pmol/g protein for SG,5 pmol/g protein for 1 PE,and 0.6 pmol/g protein for 2 PE.No significant change of adduct level was found during storage of proteins at-80℃for 1 year.
基金supported by the Natural Science Foundation of Henan (Nos. 202300410043 and 222102230091)the Key Scientific Research Project of Henan Higher Education Institutions (No. 20ZX006)the National Natural Science Foundation of China (No. 21601048)。
文摘A photoactive polyoxometalate-based metal-organic framework (POMOF),NiW-DPNDI,was synthesized by combination of Ni(Ⅱ) ions,[ZnW_(12)O_(40)]^(6–)anions,and N,N’-bis(4-pyridylmethyl)naphthalene diimide(DPNDI) molecules into one single framework.Ni W-DPNDI displays a three-dimensional structure by the strong anion···π interactions between the trapped[ZnW_(12)O_(40)]^(6–)anions and the electron-deficient naphthalenic ring centroids and theπ-πstacking interactions between DPNDI moieties.Ni W-DPNDI displayed a highly efficient hole-electron separation and ordered electron transfer under irradiation,thus ensuing its excellent photocatalysis in oxidation of styrene to produce benzaldehyde.In addition,it gave a high efficiency for styrene oxide under thermocatalytic conditions.Because the carbonic anhydrase (CA)-mimicking Ni sites and the negative electron-enriched[ZnW_(12)O_(40)]^(6–)anions are well aligned in the pores,it can promote the cycloaddition of CO_(2) with epoxides under mild conditions.
基金supported by the National Basic Research Program of China (2010CB732300)Education Commission of Shanghai Municipality (2008CG35)Science and Technology Commission of Shanghai Municipality (09ZR1408200)
文摘La-doped and La-B-doped KIT-6 mesoporous materials were prepared by direct hydrothermal synthesis with pH-adjusting method and characterized by X-ray diffractometer(XRD),nitrogen sorption,FT-IR,UV-Vis,X-ray photoelectron spectroscopy(XPS) and ICP-AES.The catalytic performance for the oxidation of styrene by hydrogen peroxide,tert-butyl hydroperoxide or oxygen was investigated.The results showed that the introduction of heteroatoms did not destroy the mesostructure of KIT-6 with cubic Ia3d space group.La or ...
文摘Metal foils for Raman scattering were prepared by HNO_3 etching method. These foils werefound to exhibit a strong SERS effect and excellent thermal stability. SERS spectra of cystaminehave been taken to illustrate the usefulness of this sample preparation method in the studies ofchemisorption. The ring opening reactions of an epoxy compound have been observed on the topof chemisorbed cystamine on silver foils.
基金H.Z.thanks the support from ITC via the Hong Kong Branch of National Precious Metals Material Engineering Research Center(NPMM),the Research Grants Council of Hong Kong(No.11301721)the Start-Up Grant(No.9380100)the grants(No.1886921)from the City University of Hong Kong.This research used 7-BM of the National Synchrotron Light Source II,a U.S.Department of Energy(DOE)Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract(No.DE-SC0012704).
文摘Amorphous nanomaterials with long-range disordered structures could possess distinct properties and promising applications,especially in catalysis,as compared with their conventional crystalline counterparts.It is imperative to achieve the controlled preparation of amorphous noble metal-based nanomaterials for the exploration of their phase-dependent applications.Here,we report a facile wet-chemical reduction strategy to synthesize various amorphous multimetallic Pd-based nanomaterials,including PdRu,PdRh,and PdRuRh.The phase-dependent catalytic performances of distinct Pd-based nanomaterials towards diverse catalytic applications have been demonstrated.Specifically,the usage of PdRu nanocatalysts with amorphous and crystalline face-centered cubic(fcc)phases can efficiently switch the ring-opening route of styrene oxide to obtain different products with high selectivity through alcoholysis reaction and hydrogenation reaction,respectively.Moreover,when used as an electrocatalyst for hydrogen evolution reaction(HER),the synthesized amorphous PdRh nanocatalyst exhibits low overpotential and high turnover frequency values,outperforming its crystalline fcc counterpart and most of the reported Pd-based HER electrocatalysts.
基金This work was supported by National Natural Science Foundation of China(81803720)Natural Science Foundation of Hunan Province(2019JJ50383)+3 种基金Natural Science Foundation of Changsha(kq2202256)Huxiang High-Level Talent Innovation Team(2018RS3072)Scientific and Technological Projects for Collaborative Prevention and Control of Birth Defect in Hunan Province(2019SK1012)Key Grant of Research and Development in Hunan Province(2020DK2002).Dr.Zhang acknowledges the support from Harvard/MIT.
文摘Toxicity assessment is a major problem in pharmaceutical candidates and industry chemicals development.However,due to the lack of practical analytical methods for DNA adduct analysis,the safety evaluation of drug and industry chemicals was severely limited.Here,we develop a DNAzyme-based method to detect DNA adduct damage for toxicity assessment of drugs and chemicals.Among 18 structural variants of G4 DNAzyme,EA2 DNAzyme exhibits an obvious DNA damaging effect of styrene oxide(SO)due to its unstable structure.The covalent binding of SO to DNAzyme disrupts the Hoogsteen hydrogen bonding sites of G-plane guanines and affects the formation of the G4 quadruplex.DNA damage chemicals reduce the peroxidase activity of the G4 DNAzyme to monitor the DNA adduct damage by disrupting the structural integrity of the G4 DNAzyme.Our method for genotoxic assessment of pharmaceutical candidates and industrial chemicals can elucidate the complex chemical pathways leading to toxicity,predict toxic effects of chemicals,and evaluate possible risks to human health.