This study explores the controllable synthesis of CuAlO_(2) using copper hydroxide and pseudo-boehmite powders as raw materials via a simple solid-phase ball milling method,along with its catalytic performance investi...This study explores the controllable synthesis of CuAlO_(2) using copper hydroxide and pseudo-boehmite powders as raw materials via a simple solid-phase ball milling method,along with its catalytic performance investigation in methanol steam reforming(MSR).Various catalysts were prepared under different conditions,such as calcination temperature,calcination atmosphere,and heating rate.Characterization techniques including BET,XRD,XPS,SEM and H2-TPR were employed to analyze the samples.The results revealed significant effects of calcination temperature on the phase compositions,specific surface area,reduction performance,and surface properties of the CA-T catalysts.Based on the findings,a synthesis route of CuAlO_(2) via the solid-phase method was proposed,highlighting the importance of high calcination temperature,nitrogen atmosphere,and low heating rate for CuAlO_(2) formation.Catalytic evaluation data demonstrated that CuAlO_(2) could catalyze MSR without pre-reduction,with the catalytic performance of CA-T catalysts being notably influenced by calcination temperature.Among the prepared catalysts,the CA-1100 catalyst exhibited the highest catalytic activity and stability.The findings of this study might be useful for the further study of the catalytic material for sustained release catalysis,including the synthesis of catalytic materials and the regulation of sustained release catalytic performance.展开更多
The new catalytic kinetic spectrophotometric method for Au（III） determination was developed and validated. It was based on the catalytic effect of gold on the oxidation of sudan red III by ammonium peroxodisulfate ...The new catalytic kinetic spectrophotometric method for Au（III） determination was developed and validated. It was based on the catalytic effect of gold on the oxidation of sudan red III by ammonium peroxodisulfate （（NH4）2S2O8） with nitrilo triacetic acid as an activator in microemulsion and H2SO4 medium. Under optimum conditions, there was the linearity of the calibration curve in the concentration range from 0 to 20 μg/L Au（Ⅲ） at 520 nm. The relative standard deviation was 3.0% with a correlation coefficient of 0.9986. The detection limit achieved was 9.75 × 10^-5 μg/mL. A new method using a column packed with sulfhydryl dextrose gel （SDG） as a solid-phase extractant has been developed for the preconcentration and separation of Au（Ⅲ） ions. The method has been applied to the determination of trace gold with satisfactory results.展开更多
Chitosan was prepared with stressing method by blending chitin and solid alkali in a single-screw extruder at given temperature and characterized by potentiometric titration,gel permeation chromatography(GPC),infrared...Chitosan was prepared with stressing method by blending chitin and solid alkali in a single-screw extruder at given temperature and characterized by potentiometric titration,gel permeation chromatography(GPC),infrared spectrum(IR)and carbon-13 magnetic resonance sperctroscopy(^(13)C NMR).Chitosan with a deacetylation degree(DD)of 76.1%was obtained at a mass ratio 0.2∶1∶1 for H_2 O/chitin/NaOH at 160℃for 12 min.Compared to conventional solution method(usually 1∶10 for chitin/NaOH),the alkali assumption greatly decreased.Molecular weight of chitosan obtained by solid-phase method(S3,M_w1.54×10^(5))was lower than that obtained by suspension method(Y2,M_w3.34×10^(5)).During deacetylation,molecular weight decreased with high reaction temperature and long reaction time but remained same at different initial ratios of NaOH/chitin.It might be concluded that degradation of chitosan was caused by breakout of the main chain of the oxidized chitosan catalyzed by alkali during the deactylation.IR and^(13)C NMR showed that structures of chitosans prepared by solid-phase method were not changed.展开更多
Complex phase transitions occur in P2-type materials during charging and discharging.A high-entropy structure can effectively inhibit the structural phase transition of a P2-type layered material.In this study,a hight...Complex phase transitions occur in P2-type materials during charging and discharging.A high-entropy structure can effectively inhibit the structural phase transition of a P2-type layered material.In this study,a hightemperature solid-phase method is used to synthesize the P2-type high-entropy fluorine oxide(HEFO)Na_(0.7)Li_(0.08)Mn(Ⅳ)_(0.21)Mn(Ⅲ)_(0.43)Mg_(0.11)Ni_(0.11)W_(0.04)Nb_(0.02)O_(1.9)F_(0.1)[■-NLM(Ⅳ)0.21M(Ⅲ)0.43F(■=NMNWO)],with a superlattice structure and Na_(2)WO_(4)coating.Na_(2)WO_(4)can effectively inhibit the complex phase transition to improve the structural stability of the material and overcome the limitations of P2-type Na_(x)TMO_(2)(TM=transition metal)via additional charge compensation.Adjusting the Mn^(3+)/Mn^(4+)ratio to increase the average valence state of Mn and introducing F^(-)and Li^(+)to inhibit the Jahn-Teller effect suppress the complex phase transition during charging and discharging.The material exhibits a good multiplicative performance(discharge specific capacity of 88.4 mAh g^(-1)at a multiplicative rate of 10C)and capacity retention(99.22%after 200 cycles at 1C in the potential window of 1.5-4.3 V).The structural stabilities of HEFO are effectively demonstrated using electrochemical in situ X-ray diffraction and ex situ X-ray photoelectron spectroscopy.Theoretical calculations reveal that the high-entropy structure effectively improves the electronic structure and charge distribution of the layered oxide material.This study provides new concepts for use in developing novel energy batteries.展开更多
This paper describes a simple, rapid and sensitive liquid chromatography tandem mass spectrometry assay for the determination of duloxetine in human plasma. A duloxetine stable labeled isotope （duloxetine ds） was us...This paper describes a simple, rapid and sensitive liquid chromatography tandem mass spectrometry assay for the determination of duloxetine in human plasma. A duloxetine stable labeled isotope （duloxetine ds） was used as an internal standard. Analyte and the internal standard were extracted from 100 btL of human plasma via solid phase extraction technique using Oasis HLB cartridges. The chromatographic separation was achieved on a Cl8 column by using a mixture of acetonitrile 5 mM ammonium acetate buffer （83：17, v/v） as the mobile phase at a flow rate of 0.9 mL/min. The calibration curve obtained was linear （r2≥0.99） over the concentration range of 0.05 101 ng/mL. Multiple-reaction monitoring mode （MRM） was used for quantification of ion transitions at rn/z 298.3/154.1 and 303.3/159.1 for the drug and the internal standard, respectively. Method validation was performed as per FDA guidelines and the results met the acceptance criteria. A run time of 2.5 min for each sample made it possible to analyze more than 300 plasma samples per day. The proposed method was found to be applicable to clinical studies.展开更多
Jiaozi Steamed Bread(JSB)has a unique aroma as a traditional staple food in China.The volatile compounds in JSBwere extracted by simultaneous distillation and extraction(SDE)and headspace solid-phasemicroextraction(HS...Jiaozi Steamed Bread(JSB)has a unique aroma as a traditional staple food in China.The volatile compounds in JSBwere extracted by simultaneous distillation and extraction(SDE)and headspace solid-phasemicroextraction(HS-SPME).These volatile substances were analyzed by gas chromatography-mass spectrometry(GC-MS)and gas chromatographyolfactometry-mass spectrometry(GC-O-MS).The results demonstrated that 61 volatile compounds were identified totally in samples,of which 15 were confirmed as potent aroma compounds with odor active values(OAVs)>1.The 15 potent aroma compounds were ethanol,1-butanol,1-pentanol,1-hexanol,heptanol,1-octen-3-ol,3-methyl-1-butanol,hexanal,heptanal,nonanal,(E)-2-heptenal,benzaldehyde,(E,E)-2,4-decadienal,2-pentylfuran and naphthalene.The SDEmethod had better linearity with coefficients of determination(R2)equal to or higher than 0.9991.Furthermore,the SDE method also achieved lower sensitivity and better repeatability and recovery than HS-SPME.This work provides reference method and parameters for future research on the flavor of JSB for commercial products.展开更多
Huwentoxin-I, a neurotoxic peptide from the spider Selenocosmia huwena, was synthesized by sol-id-phase method with Fluorenylmethoxycarbonyl amino acid pentafluorophenyl esters (Fmoc-AA-OPfp). The carboxyl and the hyd...Huwentoxin-I, a neurotoxic peptide from the spider Selenocosmia huwena, was synthesized by sol-id-phase method with Fluorenylmethoxycarbonyl amino acid pentafluorophenyl esters (Fmoc-AA-OPfp). The carboxyl and the hydroxy groups were protected by tBu; the side chains of Lys and His were protected by Roc; the guanidine group of Arg was protected by Mtr and the mercaptan group of Cys was protected by Trt. The solid-phase carrier was ethylene diamine-polyethylene-polystyrene (DEA-PEG-PS) resin. The synthetic peptide was cleaved from the resin and deprotected by a 90% TFA solution containing 5% thioanisole, 3% ethanedithiol and 2% anisole. The product was reduced with DTT and then incubated with GSSG and GSH to form the correct disulfide bond linkages. The syn-thetic peptide was purified by HPLC and then characterized by amino acid composition and sequence analysis, peptide mapping and NMR. The biological activity of the synthetic product was tested by electrophysiological method using the isolated mouse phrenic nerve diaphragm preparation. The results indicated that the synthetic huwentoxin-I has the same chemical and conformational structure and biological activity as those of the native huwentoxin-I from the spider.展开更多
MgO,CeO2 and MgO-CeO2 with different mole ratio of Mg:Ce were prepared by solid-phase burning method.Catalysts Ni/MgO,Ni/CeO2 and Ni/MgO-CeO2 were prepared by impregnation method.The catalytic properties were evaluate...MgO,CeO2 and MgO-CeO2 with different mole ratio of Mg:Ce were prepared by solid-phase burning method.Catalysts Ni/MgO,Ni/CeO2 and Ni/MgO-CeO2 were prepared by impregnation method.The catalytic properties were evaluated in ethanol steam reforming(ESR) reaction.Specific surface areas of the supports were measured by nitrogen adsorption-desorption at 77 K,and the catalysts were characterized with X-ray diffraction(XRD),temperature programmed reduction(TPR) and thermogravimetric(TG).The results showed that well...展开更多
An analytical method based on ultra-performance liquid chromatography with positive ion electrospray ionization(ESI) coupled with tandem mass spectrometry(UPLC–MS/MS) was developed and validated for the determination...An analytical method based on ultra-performance liquid chromatography with positive ion electrospray ionization(ESI) coupled with tandem mass spectrometry(UPLC–MS/MS) was developed and validated for the determination of therapeutic peptide desmopressin in human plasma. A desmopressin stable labeled isotope(desmopressin d_8) was used as an internal standard. Analyte and the internal standard were extracted from200 μL of human plasma via solid-phase extraction technique using Oasis WCX cartridges. The chromatographic separation was achieved on an Aquity UPLC HSS T3 column by using a gradient mixture of methanol and 1 m M ammonium formate buffer as the mobile phase. The calibration curve obtained was linear(r^2≥0.99)over the concentration range of 1.01–200 pg/m L. Method validation was performed as per FDA guidelines and the results met the acceptance criteria. The results of the intra-and inter-day precision and accuracy studies were well within the acceptable limits. The proposed method was successfully applied to pharmacokinetic studies in humans.展开更多
A series of TiO2-SnO2 nano-sized composite photo-catalysts containing Sn(9.3%-30.1%)were prepared from TiCl_(4)and SnCl_(4)·5H2O by using sol-gel,supercritical fluid dry and solid-phase reaction(SCFD)combination ...A series of TiO2-SnO2 nano-sized composite photo-catalysts containing Sn(9.3%-30.1%)were prepared from TiCl_(4)and SnCl_(4)·5H2O by using sol-gel,supercritical fluid dry and solid-phase reaction(SCFD)combination technology.Characterizations with X-ray diffraction(XRD),transmission electron microscopy(TEM)and Fourier Transform Infrared Spectroscopy(FTIR)showed that,in addition to anatase type TiO2,a new active phase(Ti,Sn)O2(with particle size of 2.0-4.3 nm)formed,and there were no SnO2 crystals observed in the range of the doping concentration studied.Photo-catalytic reaction of phenol was used as a model reaction to evaluate the catalytic activities of the obtained catalysts.Compared with pure TiO2 or Ti-Sn catalyst prepared with general sol-gel method,Ti-Sn nano-composite photo-catalyst thus obtained showed significant improvement in catalytic activity.The photo-catalytic degradation rate of phenol could reach as high as 93.5%after 7 h.The preparation conditions of the new phase(Ti,Sn)O2 were investigated and its catalytic mechanism was proposed.The photo-catalytic particles prepared using SCFD combination technology exhibited small particle size,large surface area and high activity.展开更多
A series of Dy^(3+)/Eu^(3+) single doped and co-doped SrLaAlO_(4) phosphors was synthesized by the traditional high-temperature solid-state method,and their structure,morphology and optical properties were characteriz...A series of Dy^(3+)/Eu^(3+) single doped and co-doped SrLaAlO_(4) phosphors was synthesized by the traditional high-temperature solid-state method,and their structure,morphology and optical properties were characterized.The X-ray diffraction(XRD) shows a small amount of doping with Dy^(3+) and Eu^(3+) does not change the crystal structure of the matrix SrLaAlO_(4) and the best synthesis temperature is 1450℃.The scanning electron microscopy(SEM) indicates the particle size directly ranges from 1 to 5μm roughly and the energy dispersive spectroscopy(EDS) patterns show that SrLaAlO_(4):Dy^(3+) phosphor and SrLaAlO_(4):Dy^(3+),Eu^(3+) phosphor were successfully synthesized.SrLaAlO_(4):Dy^(3+) phosphor can be effectively excited by near-ultraviolet light,producing two strong emission lights at 483 nm(blue light) and 579 nm(yellow light),presenting a cold white light;SrLaAlO_(4):Eu^(3+) phosphor can be effectively excited by nearultraviolet light,producing red lights at 622 nm;the characteristic emission peaks of Dy^(3+) and Eu^(3+)can be shown simultaneously under the same excitation wavelength in SrLaAlO_(4):Dy^(3+), Eu^(3+) phosphor.By changing the relative doping concentration ratio of Dy^(3+) and Eu^(3+),the modulation of SrLaAlO_(4):Dy^(3+),Eu3+phosphor from cold white to warm white light can be achieved.In addition,the study of the luminescent mechanism and lifetime shows that there is energy transfer between Dy^(3+) and Eu^(3+) in SrLaAlO_(4):Dy^(3+),Eu^(3+) phosphor.展开更多
[Objectives] To analyze the volatile components in different parts of Polygala japonica Houtt. and compare the differences of these volatile components. [Methods] The volatile components in different parts of P. japon...[Objectives] To analyze the volatile components in different parts of Polygala japonica Houtt. and compare the differences of these volatile components. [Methods] The volatile components in different parts of P. japonica Houtt. were analyzed by the headspace solid-phase microextraction( HS-SPME) combined with GC-MS,and the relative percentage of each component was determined by peak area normalization. [Results] Thirty kinds of volatile components were identified from the leaves and rhizomes of P. japonica Houtt.,mainly including olefins,aromatic hydrocarbons,alkanes and esters. [Conclusions] The volatile components in different parts of P. japonica Houtt. were different,and there may be difference in the medicinal value of volatile components in different parts,thus it is required to take an overall consideration of these differences in the development and utilization of P. japonica Houtt.展开更多
Iodine ion is one of the most indispensable anions in living organisms,particularly being an important substance for the synthesis of thyroid hormones.Curcumin is a yellow-orange polyphenol compound derived from the r...Iodine ion is one of the most indispensable anions in living organisms,particularly being an important substance for the synthesis of thyroid hormones.Curcumin is a yellow-orange polyphenol compound derived from the rhizome of Curcuma longa L.,which has been commonly used as a spice and natural coloring agent,food additives,cosmetics as well as Chinese medicine.However,excess curcumin may cause DNA inactivation,lead to a decrease in intracellular ATP levels,and trigger the tissue necrosis.Therefore,quantitative detection of iodine and curcumin is of great significance in the fields of food and life sciences.Herein,we develop nitrogen-doped fluorescent carbon dots(NCDs)as a multi-mechanism detection for iodide and curcumin in actual complex biological and food samples,which was prepared by a one-step solid-phase synthesis using tartaric acid and urea as precursors without adding any other reagents.An assembled NCDs-Hg^(2+) fluorescence-enhanced sensor for the quantitative detection of I^(-) was established based on a fluorescence“turn-off-on”mechanism in a linear range of 0.3-15μM with a detection limit of 69.4 nM and successfully quantified trace amounts of I^(-) in water samples and urine sample.Meanwhile,the as-synthesized NCDs also can be used as a fluorescent quenched sensor for curcumin detection based on the synergistic internal filtration effect(IFE)and static quenching,achieving a good linear range of 0.1-20μM with a satisfactory detection limit of 29.8 nM.These results indicate that carbon dots are potential sensing materials for iodine and curcumin detection for the good of our health.展开更多
The synthesis of an Asp lactam derivative of A-183,a selective inhibitor of Factor 7a with good anticoagulant and antithrombotic activity,is described.Our synthesis depends on the use of a removable backbone modificat...The synthesis of an Asp lactam derivative of A-183,a selective inhibitor of Factor 7a with good anticoagulant and antithrombotic activity,is described.Our synthesis depends on the use of a removable backbone modification(RBM)strategy to prevent aspartimide formation,which thwarted all attempts to synthesize this target using direct solid-phase peptide synthesis.Validation of the RBM strategy in the synthesis of a second Asp lactam derivative was also accomplished.The RBM strategy is therefore proposed as a general method for the synthesis of Asp lactam cyclic peptides.展开更多
基金supported by the Scientific Research Foundation for High-level Talents of Anhui University of Science and Technology(2023yjrc51)the National Natural Science Foundation of China(22172184)+2 种基金the Foundation of State Key Laboratory of Coal Conversion(J24-25-603)the Fundamental Research Project of ICC-CAS(SCJC-DT-2023-01)Weiqiao-UCAS Special Projects on Low-Carbon Technology Development(GYY-DTFZ-2022-015)。
文摘This study explores the controllable synthesis of CuAlO_(2) using copper hydroxide and pseudo-boehmite powders as raw materials via a simple solid-phase ball milling method,along with its catalytic performance investigation in methanol steam reforming(MSR).Various catalysts were prepared under different conditions,such as calcination temperature,calcination atmosphere,and heating rate.Characterization techniques including BET,XRD,XPS,SEM and H2-TPR were employed to analyze the samples.The results revealed significant effects of calcination temperature on the phase compositions,specific surface area,reduction performance,and surface properties of the CA-T catalysts.Based on the findings,a synthesis route of CuAlO_(2) via the solid-phase method was proposed,highlighting the importance of high calcination temperature,nitrogen atmosphere,and low heating rate for CuAlO_(2) formation.Catalytic evaluation data demonstrated that CuAlO_(2) could catalyze MSR without pre-reduction,with the catalytic performance of CA-T catalysts being notably influenced by calcination temperature.Among the prepared catalysts,the CA-1100 catalyst exhibited the highest catalytic activity and stability.The findings of this study might be useful for the further study of the catalytic material for sustained release catalysis,including the synthesis of catalytic materials and the regulation of sustained release catalytic performance.
文摘The new catalytic kinetic spectrophotometric method for Au（III） determination was developed and validated. It was based on the catalytic effect of gold on the oxidation of sudan red III by ammonium peroxodisulfate （（NH4）2S2O8） with nitrilo triacetic acid as an activator in microemulsion and H2SO4 medium. Under optimum conditions, there was the linearity of the calibration curve in the concentration range from 0 to 20 μg/L Au（Ⅲ） at 520 nm. The relative standard deviation was 3.0% with a correlation coefficient of 0.9986. The detection limit achieved was 9.75 × 10^-5 μg/mL. A new method using a column packed with sulfhydryl dextrose gel （SDG） as a solid-phase extractant has been developed for the preconcentration and separation of Au（Ⅲ） ions. The method has been applied to the determination of trace gold with satisfactory results.
基金Supported by the National Natural Science Foundation of China(29977014)
文摘Chitosan was prepared with stressing method by blending chitin and solid alkali in a single-screw extruder at given temperature and characterized by potentiometric titration,gel permeation chromatography(GPC),infrared spectrum(IR)and carbon-13 magnetic resonance sperctroscopy(^(13)C NMR).Chitosan with a deacetylation degree(DD)of 76.1%was obtained at a mass ratio 0.2∶1∶1 for H_2 O/chitin/NaOH at 160℃for 12 min.Compared to conventional solution method(usually 1∶10 for chitin/NaOH),the alkali assumption greatly decreased.Molecular weight of chitosan obtained by solid-phase method(S3,M_w1.54×10^(5))was lower than that obtained by suspension method(Y2,M_w3.34×10^(5)).During deacetylation,molecular weight decreased with high reaction temperature and long reaction time but remained same at different initial ratios of NaOH/chitin.It might be concluded that degradation of chitosan was caused by breakout of the main chain of the oxidized chitosan catalyzed by alkali during the deactylation.IR and^(13)C NMR showed that structures of chitosans prepared by solid-phase method were not changed.
基金financially supported by the Guizhou Provincial Basic Research Program(Natural Science)(No.QKHJC-ZK[2023]YB051)the Natural Science Special Foundation of Guizhou University(No.GDTGH[2022]33)+2 种基金the Natural Science Research project of the Education Department of Guizhou Province(No.QJJ[2022]001)the National Natural Science Foundation of China(No.52161029)the Science and Technology Innovation Team of Education Agency in Guizhou Province(No.Qian Jiao Ji[2023]056)
文摘Complex phase transitions occur in P2-type materials during charging and discharging.A high-entropy structure can effectively inhibit the structural phase transition of a P2-type layered material.In this study,a hightemperature solid-phase method is used to synthesize the P2-type high-entropy fluorine oxide(HEFO)Na_(0.7)Li_(0.08)Mn(Ⅳ)_(0.21)Mn(Ⅲ)_(0.43)Mg_(0.11)Ni_(0.11)W_(0.04)Nb_(0.02)O_(1.9)F_(0.1)[■-NLM(Ⅳ)0.21M(Ⅲ)0.43F(■=NMNWO)],with a superlattice structure and Na_(2)WO_(4)coating.Na_(2)WO_(4)can effectively inhibit the complex phase transition to improve the structural stability of the material and overcome the limitations of P2-type Na_(x)TMO_(2)(TM=transition metal)via additional charge compensation.Adjusting the Mn^(3+)/Mn^(4+)ratio to increase the average valence state of Mn and introducing F^(-)and Li^(+)to inhibit the Jahn-Teller effect suppress the complex phase transition during charging and discharging.The material exhibits a good multiplicative performance(discharge specific capacity of 88.4 mAh g^(-1)at a multiplicative rate of 10C)and capacity retention(99.22%after 200 cycles at 1C in the potential window of 1.5-4.3 V).The structural stabilities of HEFO are effectively demonstrated using electrochemical in situ X-ray diffraction and ex situ X-ray photoelectron spectroscopy.Theoretical calculations reveal that the high-entropy structure effectively improves the electronic structure and charge distribution of the layered oxide material.This study provides new concepts for use in developing novel energy batteries.
文摘This paper describes a simple, rapid and sensitive liquid chromatography tandem mass spectrometry assay for the determination of duloxetine in human plasma. A duloxetine stable labeled isotope （duloxetine ds） was used as an internal standard. Analyte and the internal standard were extracted from 100 btL of human plasma via solid phase extraction technique using Oasis HLB cartridges. The chromatographic separation was achieved on a Cl8 column by using a mixture of acetonitrile 5 mM ammonium acetate buffer （83：17, v/v） as the mobile phase at a flow rate of 0.9 mL/min. The calibration curve obtained was linear （r2≥0.99） over the concentration range of 0.05 101 ng/mL. Multiple-reaction monitoring mode （MRM） was used for quantification of ion transitions at rn/z 298.3/154.1 and 303.3/159.1 for the drug and the internal standard, respectively. Method validation was performed as per FDA guidelines and the results met the acceptance criteria. A run time of 2.5 min for each sample made it possible to analyze more than 300 plasma samples per day. The proposed method was found to be applicable to clinical studies.
基金This project was supported by the National Natural Science Foundation of China(No.31701635)the Key Laboratory of Staple Grain Processing,Ministry of Agriculture(No.DZLS201703)the Henan University of Technology High-level Talents Fund(No.2015BS009).
文摘Jiaozi Steamed Bread(JSB)has a unique aroma as a traditional staple food in China.The volatile compounds in JSBwere extracted by simultaneous distillation and extraction(SDE)and headspace solid-phasemicroextraction(HS-SPME).These volatile substances were analyzed by gas chromatography-mass spectrometry(GC-MS)and gas chromatographyolfactometry-mass spectrometry(GC-O-MS).The results demonstrated that 61 volatile compounds were identified totally in samples,of which 15 were confirmed as potent aroma compounds with odor active values(OAVs)>1.The 15 potent aroma compounds were ethanol,1-butanol,1-pentanol,1-hexanol,heptanol,1-octen-3-ol,3-methyl-1-butanol,hexanal,heptanal,nonanal,(E)-2-heptenal,benzaldehyde,(E,E)-2,4-decadienal,2-pentylfuran and naphthalene.The SDEmethod had better linearity with coefficients of determination(R2)equal to or higher than 0.9991.Furthermore,the SDE method also achieved lower sensitivity and better repeatability and recovery than HS-SPME.This work provides reference method and parameters for future research on the flavor of JSB for commercial products.
基金Project supported by the National Natural Science Foundation of China and Hunan Educational Committee.
文摘Huwentoxin-I, a neurotoxic peptide from the spider Selenocosmia huwena, was synthesized by sol-id-phase method with Fluorenylmethoxycarbonyl amino acid pentafluorophenyl esters (Fmoc-AA-OPfp). The carboxyl and the hydroxy groups were protected by tBu; the side chains of Lys and His were protected by Roc; the guanidine group of Arg was protected by Mtr and the mercaptan group of Cys was protected by Trt. The solid-phase carrier was ethylene diamine-polyethylene-polystyrene (DEA-PEG-PS) resin. The synthetic peptide was cleaved from the resin and deprotected by a 90% TFA solution containing 5% thioanisole, 3% ethanedithiol and 2% anisole. The product was reduced with DTT and then incubated with GSSG and GSH to form the correct disulfide bond linkages. The syn-thetic peptide was purified by HPLC and then characterized by amino acid composition and sequence analysis, peptide mapping and NMR. The biological activity of the synthetic product was tested by electrophysiological method using the isolated mouse phrenic nerve diaphragm preparation. The results indicated that the synthetic huwentoxin-I has the same chemical and conformational structure and biological activity as those of the native huwentoxin-I from the spider.
基金supported by the National Natural Science Foundation of China (20863006)the Natural Science Foundation of Jiangxi Province, China (0620042)Department of Education of Jiangxi Province (GJJ09078)
文摘MgO,CeO2 and MgO-CeO2 with different mole ratio of Mg:Ce were prepared by solid-phase burning method.Catalysts Ni/MgO,Ni/CeO2 and Ni/MgO-CeO2 were prepared by impregnation method.The catalytic properties were evaluated in ethanol steam reforming(ESR) reaction.Specific surface areas of the supports were measured by nitrogen adsorption-desorption at 77 K,and the catalysts were characterized with X-ray diffraction(XRD),temperature programmed reduction(TPR) and thermogravimetric(TG).The results showed that well...
文摘An analytical method based on ultra-performance liquid chromatography with positive ion electrospray ionization(ESI) coupled with tandem mass spectrometry(UPLC–MS/MS) was developed and validated for the determination of therapeutic peptide desmopressin in human plasma. A desmopressin stable labeled isotope(desmopressin d_8) was used as an internal standard. Analyte and the internal standard were extracted from200 μL of human plasma via solid-phase extraction technique using Oasis WCX cartridges. The chromatographic separation was achieved on an Aquity UPLC HSS T3 column by using a gradient mixture of methanol and 1 m M ammonium formate buffer as the mobile phase. The calibration curve obtained was linear(r^2≥0.99)over the concentration range of 1.01–200 pg/m L. Method validation was performed as per FDA guidelines and the results met the acceptance criteria. The results of the intra-and inter-day precision and accuracy studies were well within the acceptable limits. The proposed method was successfully applied to pharmacokinetic studies in humans.
基金The authors thank the National Natural Scir nce Foun-dation of China(No.20076004)the National Development Project of High Technology(No.2001AA322030)the Doctoral Program of Higher Education(No.2000001005)for the financial support of this project.
文摘A series of TiO2-SnO2 nano-sized composite photo-catalysts containing Sn(9.3%-30.1%)were prepared from TiCl_(4)and SnCl_(4)·5H2O by using sol-gel,supercritical fluid dry and solid-phase reaction(SCFD)combination technology.Characterizations with X-ray diffraction(XRD),transmission electron microscopy(TEM)and Fourier Transform Infrared Spectroscopy(FTIR)showed that,in addition to anatase type TiO2,a new active phase(Ti,Sn)O2(with particle size of 2.0-4.3 nm)formed,and there were no SnO2 crystals observed in the range of the doping concentration studied.Photo-catalytic reaction of phenol was used as a model reaction to evaluate the catalytic activities of the obtained catalysts.Compared with pure TiO2 or Ti-Sn catalyst prepared with general sol-gel method,Ti-Sn nano-composite photo-catalyst thus obtained showed significant improvement in catalytic activity.The photo-catalytic degradation rate of phenol could reach as high as 93.5%after 7 h.The preparation conditions of the new phase(Ti,Sn)O2 were investigated and its catalytic mechanism was proposed.The photo-catalytic particles prepared using SCFD combination technology exhibited small particle size,large surface area and high activity.
基金Project supported by Outstanding Young and Middle-aged Scientific Innovation Team of Colleges and Universities of Hubei Province(T2020008)。
文摘A series of Dy^(3+)/Eu^(3+) single doped and co-doped SrLaAlO_(4) phosphors was synthesized by the traditional high-temperature solid-state method,and their structure,morphology and optical properties were characterized.The X-ray diffraction(XRD) shows a small amount of doping with Dy^(3+) and Eu^(3+) does not change the crystal structure of the matrix SrLaAlO_(4) and the best synthesis temperature is 1450℃.The scanning electron microscopy(SEM) indicates the particle size directly ranges from 1 to 5μm roughly and the energy dispersive spectroscopy(EDS) patterns show that SrLaAlO_(4):Dy^(3+) phosphor and SrLaAlO_(4):Dy^(3+),Eu^(3+) phosphor were successfully synthesized.SrLaAlO_(4):Dy^(3+) phosphor can be effectively excited by near-ultraviolet light,producing two strong emission lights at 483 nm(blue light) and 579 nm(yellow light),presenting a cold white light;SrLaAlO_(4):Eu^(3+) phosphor can be effectively excited by nearultraviolet light,producing red lights at 622 nm;the characteristic emission peaks of Dy^(3+) and Eu^(3+)can be shown simultaneously under the same excitation wavelength in SrLaAlO_(4):Dy^(3+), Eu^(3+) phosphor.By changing the relative doping concentration ratio of Dy^(3+) and Eu^(3+),the modulation of SrLaAlO_(4):Dy^(3+),Eu3+phosphor from cold white to warm white light can be achieved.In addition,the study of the luminescent mechanism and lifetime shows that there is energy transfer between Dy^(3+) and Eu^(3+) in SrLaAlO_(4):Dy^(3+),Eu^(3+) phosphor.
文摘[Objectives] To analyze the volatile components in different parts of Polygala japonica Houtt. and compare the differences of these volatile components. [Methods] The volatile components in different parts of P. japonica Houtt. were analyzed by the headspace solid-phase microextraction( HS-SPME) combined with GC-MS,and the relative percentage of each component was determined by peak area normalization. [Results] Thirty kinds of volatile components were identified from the leaves and rhizomes of P. japonica Houtt.,mainly including olefins,aromatic hydrocarbons,alkanes and esters. [Conclusions] The volatile components in different parts of P. japonica Houtt. were different,and there may be difference in the medicinal value of volatile components in different parts,thus it is required to take an overall consideration of these differences in the development and utilization of P. japonica Houtt.
基金Financial supports from the XingLiao Talent Project Grants(No.XLYC1902076)the University of Science and Technology Liaoning Talent Project Grants(No.601010302)are highly appreciated.
文摘Iodine ion is one of the most indispensable anions in living organisms,particularly being an important substance for the synthesis of thyroid hormones.Curcumin is a yellow-orange polyphenol compound derived from the rhizome of Curcuma longa L.,which has been commonly used as a spice and natural coloring agent,food additives,cosmetics as well as Chinese medicine.However,excess curcumin may cause DNA inactivation,lead to a decrease in intracellular ATP levels,and trigger the tissue necrosis.Therefore,quantitative detection of iodine and curcumin is of great significance in the fields of food and life sciences.Herein,we develop nitrogen-doped fluorescent carbon dots(NCDs)as a multi-mechanism detection for iodide and curcumin in actual complex biological and food samples,which was prepared by a one-step solid-phase synthesis using tartaric acid and urea as precursors without adding any other reagents.An assembled NCDs-Hg^(2+) fluorescence-enhanced sensor for the quantitative detection of I^(-) was established based on a fluorescence“turn-off-on”mechanism in a linear range of 0.3-15μM with a detection limit of 69.4 nM and successfully quantified trace amounts of I^(-) in water samples and urine sample.Meanwhile,the as-synthesized NCDs also can be used as a fluorescent quenched sensor for curcumin detection based on the synergistic internal filtration effect(IFE)and static quenching,achieving a good linear range of 0.1-20μM with a satisfactory detection limit of 29.8 nM.These results indicate that carbon dots are potential sensing materials for iodine and curcumin detection for the good of our health.
基金supported by the National Key R&D Program of China(No.2017YFA0505200)the National Natural Science Foundation of China(Nos.91753205,21877024,21621003,81621002)the Fundamental Research Funds for the Central Universities(No.JZ2019HGPB0105).
文摘The synthesis of an Asp lactam derivative of A-183,a selective inhibitor of Factor 7a with good anticoagulant and antithrombotic activity,is described.Our synthesis depends on the use of a removable backbone modification(RBM)strategy to prevent aspartimide formation,which thwarted all attempts to synthesize this target using direct solid-phase peptide synthesis.Validation of the RBM strategy in the synthesis of a second Asp lactam derivative was also accomplished.The RBM strategy is therefore proposed as a general method for the synthesis of Asp lactam cyclic peptides.
