Dieulafoy's lesion (DL) is a rare but important cause of obscure gastrointestinal bleeding that may be over-looked during diagnostic endoscopy. Mortality rates are similar to those of other causes for gastrointest...Dieulafoy's lesion (DL) is a rare but important cause of obscure gastrointestinal bleeding that may be over-looked during diagnostic endoscopy. Mortality rates are similar to those of other causes for gastrointestinal bleeding. Diagnosis by upper endoscopy is the modal-ity of choice during acute bleeding. In the absence of active bleeding, the lesion resembles a raised nipple or visible vessel. There are no guidelines regarding effective selective therapy for DL, when diagnosed, en-doscopist experience is the major determinant of the treatment strategy. Following our strategy, an expert endoscopist with a skilled assistant should have a high rate of successful DL diagnosis when an obscured gas-trointestinal lesion is suspected. Cyanoacryltes com-pounds have been used successfully in management of Gastric varices and DLs. To our knowledge, there have been no previous reports regarding use of isoamyl-2-cyanoacrylate (AMCRYLATE ; Concord Drugs Ltd.,Hyderabad, India) as an effective therapy for gastric DL without serious complications. In our case study, Isoamyl-2-cyanoacrylate (AMCRYLATE) was effective and safe for treating DL. Surgical wedge resection of the lesion should be considered as a therapeutic option if endoscopic therapy fails.展开更多
Antimony-doped tin hydroxide colloid precipitates were prepared by hydrolysis of SnCl4·5H2O and SbCl3 ethanol solutions. Isoamyl acetate was selected as azeotropic drying solvent and was compared with the most co...Antimony-doped tin hydroxide colloid precipitates were prepared by hydrolysis of SnCl4·5H2O and SbCl3 ethanol solutions. Isoamyl acetate was selected as azeotropic drying solvent and was compared with the most commonly used n-butanol solvent on treating precipitate for low hard agglomeration precursor powders. The FT-IR, BET, XRD, and TEM results of the precursor powders and calcinated antimony-doped tin oxide powders were recorded. The results demonstrate that isoamyl acetate is an excellent azeotropic drying solvent that can effectively prevent the agglomeration of particles and greatly improve the fluffiness of the obtained dried powders. After these precursor powders are calcined, antimony-doped tin oxide nanopowders with tetragonal rutile structure and high dispersivity can be obtained.展开更多
Layered organic-inorganic hybrids represent a class of technologically important materials due to their promising physical properties.In this report,two new layered organic-inorganic hybrid compounds(IAA)_(2)CdX_(4)(I...Layered organic-inorganic hybrids represent a class of technologically important materials due to their promising physical properties.In this report,two new layered organic-inorganic hybrid compounds(IAA)_(2)CdX_(4)(IAA=isoamyl-ammonium cation,X=Cl,1 and Br,2)have been successfully synthesized and characterized.展开更多
In this study,two acidic ionic liquids were innovatively selected to replace traditional acetic acid as catalysts and templates for the preparation of covalent organic frameworks(COFs)materials in aqueous phase at roo...In this study,two acidic ionic liquids were innovatively selected to replace traditional acetic acid as catalysts and templates for the preparation of covalent organic frameworks(COFs)materials in aqueous phase at room tem-perature.At the same time,the synthesized COFs carrier achieved in-situ encapsulation and immobilization of Candida rugosa lipase(CRL)in aqueous phase at room temperature.The optimum immobilized lipases COF-COOH-M and COF-SO_(3)H-M were obtained by adjusting the reaction conditions.Their enzyme loadings were 210.17 mg/g and 258.47 mg/g,respectively,and the specific activity retention compared to free lipase was 67.11%and 78.42%,respectively.The carrier and immobilized lipase were characterized by FT-IR,XRD,BET and TG.The catalytic performance and operational stability of the immobilized lipase were investigated.The results showed that both immobilized lipases showed better stability than free lipases,and COF-SO_(3)H-M had the best performance.The relative activity retention of COF-SO_(3)H-M after incubation at 60℃ for 60 min was 4.35 times that of free lipase.After 28 days of storage at 4℃,the relative activity of COF-SO_(3)H-M remained 75.10%,while that of free lipase was only 24.61%.The COF-SO_(3)H-M was applied as biocatalyst for isoamyl acetate preparation at 50℃ for 7 h,and the yield of isoamyl acetate was as high as 86.94%,which was 22.12%higher than that of free lipase.展开更多
In this study,enzyme carrier covalent organic frameworks(COFs)was prepared by acidic ionic liquids as catalysts and templates simultaneously.At the same time,Candida rugosa lipase(CRL)was immobilized in COFs carrier b...In this study,enzyme carrier covalent organic frameworks(COFs)was prepared by acidic ionic liquids as catalysts and templates simultaneously.At the same time,Candida rugosa lipase(CRL)was immobilized in COFs carrier by in-situ encapsulation in aqueous phase at room temperature.Furthermore,the above-prepared immobilized lipase(COF-SO_(3)H-M)was applied to catalyze the synthesis of isoamyl acetate in different deep eutectic solvent(DES)environments.The optimal reaction conditions were determined as follows:the molar ratio of acetic acid and isopentyl alcohol was 1:5,the addition of immobilized lipase was 2.0 wt%,the temperature was 50℃,the reaction time was 7 h,and the addition of ZnCl_(2)-DMIM was 18.63 wt%.Under the optimal reaction conditions and DES,the yield of isoamyl acetate was up to 98.26%.After the immobilized lipase was reused nine times,combined with SEM and TEM material morphology analysis,it was found that the outer frame of the COFs enzyme carrier was still not significantly damaged.The experimental results showed that the yield of catalytic synthesis of isoamyl acetate was 82.91%.In addition,the difference of lipase in DES and n-hexane was analyzed from the microscopic level by molecular docking and dynamics simulation.The results showed that lipase had a more stable structure and larger solvent accessible area(194.9405 nm^(2))in DES.The above results indicate that COF-SO_(3)H-M as an immobilized enzyme catalyst is feasible for the efficient synthesis of isoamyl acetate in DES.展开更多
Because the volatile content of isoamyl alcohol increases sharply on the seventh day of wheat mildew infection,isoamyl alcohol can be used as an early biomarker of wheat mildew infection.Currently,only a few sensors f...Because the volatile content of isoamyl alcohol increases sharply on the seventh day of wheat mildew infection,isoamyl alcohol can be used as an early biomarker of wheat mildew infection.Currently,only a few sensors for isoamyl alcohol detection have been reported,and these sensors still suffer from low sensitivity and poor moisture resistance.Herein,the isoamyl alcohol sensitivity of 5 at%Er@LaFeO_(3)(ELFO)was enhanced by loading Ag nanoparticles on the surface of the ELFO microspheres,while the optimal operating temperature was reduced.The moisture resistance of Ag/ELFO was improved by the incorporation of g-C_(3)N_(4)nanosheets(NSs)on the surface of Ag/ELFO through electrostatic self-assembly.Given the requirements for practical applications in grain granaries,the sensing behavior of a Ag/ELFO-based sensor incorporating g-C_(3)N_(4)NSs at 20%relative humidity(RH)was systematically studied,and the sensor demonstrated excellent repeatability,long-term stability,and superior selectivity(791 at 50 ppm)for isoamyl alcohol with a low limit of detection(LOD=75 ppb).Furthermore,the practical results obtained for wheat at different mildew stages further confirmed the potential of the g-C_(3)N_(4)/Ag/ELFO-based sensor for monitoring the early mildew stage of wheat.This work may offer guidance for enhancing the moisture resistance of gas-sensitive materials through the strategy of employing composite nanomaterials.展开更多
In this study,Candida rugosa lipase(CRL)was immobilized on the silica carrier SBA-15 by physical adsorption,then mixed with hydrophobically modified sodium alginate and dropped into calcium chloride solution.Finally,t...In this study,Candida rugosa lipase(CRL)was immobilized on the silica carrier SBA-15 by physical adsorption,then mixed with hydrophobically modified sodium alginate and dropped into calcium chloride solution.Finally,the adsorption-embedding immobilized lipase(L-SBA-15-Mgel)was successfully prepared.The conformation of the carrier before and after lipase immobilization were analyzed by scanning electron microscopy(SEM),thermogravimetric analysis(TGA),Fourier transform infrared spectroscopy(FT-IR)and other characterization techniques.The molecular docking and molecular dynamics simulation of CRL and modifier dodecyl glycidyl ether(DGE)ligand were carried out to analyze the potential influence of modifier on enzyme characteristics.The basic enzymatic properties including the activity,stability and reaction kinetic parameters of the immobilized lipase L-SBA-15-Mgel were studied.L-SBA-15-Mgel showed good storage stability and reusability.After 16 days of storage,the activity retention was 47.85%,and there was still 63.20%of the residual activity after seven cycles of reuse.The immobilized lipase was applied to the efficient synthesis of food flavor ester isoamyl acetate.Under the reaction conditions of 50℃ and 200 rpm,the highest yield of isoamyl acetate catalyzed by L-SBA-15-Mgel was 85.19%.展开更多
Isoamyl acetate was catalytically synthesized by SnCl 4·5H 2O. The effects of reaction time, catalyst amount,and ratio of glacial acetic acid to isoamyl alcohol were investgated. The results showed that at condit...Isoamyl acetate was catalytically synthesized by SnCl 4·5H 2O. The effects of reaction time, catalyst amount,and ratio of glacial acetic acid to isoamyl alcohol were investgated. The results showed that at condition of molar ratio of HAc to isoamyl alcohol=1∶1 08, that of SnCl 4·5H 2O to HAc=1∶100, 150 ℃, 1 h isoamyl acetate can be obtained in yield of 95 6%.展开更多
文摘Dieulafoy's lesion (DL) is a rare but important cause of obscure gastrointestinal bleeding that may be over-looked during diagnostic endoscopy. Mortality rates are similar to those of other causes for gastrointestinal bleeding. Diagnosis by upper endoscopy is the modal-ity of choice during acute bleeding. In the absence of active bleeding, the lesion resembles a raised nipple or visible vessel. There are no guidelines regarding effective selective therapy for DL, when diagnosed, en-doscopist experience is the major determinant of the treatment strategy. Following our strategy, an expert endoscopist with a skilled assistant should have a high rate of successful DL diagnosis when an obscured gas-trointestinal lesion is suspected. Cyanoacryltes com-pounds have been used successfully in management of Gastric varices and DLs. To our knowledge, there have been no previous reports regarding use of isoamyl-2-cyanoacrylate (AMCRYLATE ; Concord Drugs Ltd.,Hyderabad, India) as an effective therapy for gastric DL without serious complications. In our case study, Isoamyl-2-cyanoacrylate (AMCRYLATE) was effective and safe for treating DL. Surgical wedge resection of the lesion should be considered as a therapeutic option if endoscopic therapy fails.
基金Project(50471027) supported by the National Natural Science Foundation of China
文摘Antimony-doped tin hydroxide colloid precipitates were prepared by hydrolysis of SnCl4·5H2O and SbCl3 ethanol solutions. Isoamyl acetate was selected as azeotropic drying solvent and was compared with the most commonly used n-butanol solvent on treating precipitate for low hard agglomeration precursor powders. The FT-IR, BET, XRD, and TEM results of the precursor powders and calcinated antimony-doped tin oxide powders were recorded. The results demonstrate that isoamyl acetate is an excellent azeotropic drying solvent that can effectively prevent the agglomeration of particles and greatly improve the fluffiness of the obtained dried powders. After these precursor powders are calcined, antimony-doped tin oxide nanopowders with tetragonal rutile structure and high dispersivity can be obtained.
基金supported by the National Natural Science Foundation of China(21531008)the Scientific Research Foundation of Graduate School of Southeast University(YBJJ1629).
文摘Layered organic-inorganic hybrids represent a class of technologically important materials due to their promising physical properties.In this report,two new layered organic-inorganic hybrid compounds(IAA)_(2)CdX_(4)(IAA=isoamyl-ammonium cation,X=Cl,1 and Br,2)have been successfully synthesized and characterized.
基金funded by the National Natural Science Foundation of China(No.22178153)National Key Research and Development Pro-gram of China(No.2021YFC2103800)Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘In this study,two acidic ionic liquids were innovatively selected to replace traditional acetic acid as catalysts and templates for the preparation of covalent organic frameworks(COFs)materials in aqueous phase at room tem-perature.At the same time,the synthesized COFs carrier achieved in-situ encapsulation and immobilization of Candida rugosa lipase(CRL)in aqueous phase at room temperature.The optimum immobilized lipases COF-COOH-M and COF-SO_(3)H-M were obtained by adjusting the reaction conditions.Their enzyme loadings were 210.17 mg/g and 258.47 mg/g,respectively,and the specific activity retention compared to free lipase was 67.11%and 78.42%,respectively.The carrier and immobilized lipase were characterized by FT-IR,XRD,BET and TG.The catalytic performance and operational stability of the immobilized lipase were investigated.The results showed that both immobilized lipases showed better stability than free lipases,and COF-SO_(3)H-M had the best performance.The relative activity retention of COF-SO_(3)H-M after incubation at 60℃ for 60 min was 4.35 times that of free lipase.After 28 days of storage at 4℃,the relative activity of COF-SO_(3)H-M remained 75.10%,while that of free lipase was only 24.61%.The COF-SO_(3)H-M was applied as biocatalyst for isoamyl acetate preparation at 50℃ for 7 h,and the yield of isoamyl acetate was as high as 86.94%,which was 22.12%higher than that of free lipase.
基金funded by the National Natural Science Foundation of China(No.22178153)National Key Research and Development Program of China(No.2021YFC2103800)Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘In this study,enzyme carrier covalent organic frameworks(COFs)was prepared by acidic ionic liquids as catalysts and templates simultaneously.At the same time,Candida rugosa lipase(CRL)was immobilized in COFs carrier by in-situ encapsulation in aqueous phase at room temperature.Furthermore,the above-prepared immobilized lipase(COF-SO_(3)H-M)was applied to catalyze the synthesis of isoamyl acetate in different deep eutectic solvent(DES)environments.The optimal reaction conditions were determined as follows:the molar ratio of acetic acid and isopentyl alcohol was 1:5,the addition of immobilized lipase was 2.0 wt%,the temperature was 50℃,the reaction time was 7 h,and the addition of ZnCl_(2)-DMIM was 18.63 wt%.Under the optimal reaction conditions and DES,the yield of isoamyl acetate was up to 98.26%.After the immobilized lipase was reused nine times,combined with SEM and TEM material morphology analysis,it was found that the outer frame of the COFs enzyme carrier was still not significantly damaged.The experimental results showed that the yield of catalytic synthesis of isoamyl acetate was 82.91%.In addition,the difference of lipase in DES and n-hexane was analyzed from the microscopic level by molecular docking and dynamics simulation.The results showed that lipase had a more stable structure and larger solvent accessible area(194.9405 nm^(2))in DES.The above results indicate that COF-SO_(3)H-M as an immobilized enzyme catalyst is feasible for the efficient synthesis of isoamyl acetate in DES.
基金supported by the Outstanding Youth Foundation of Jiangsu Province of China(No.BK20211548)the Qinglan Project of Yangzhou University,and the Yangzhou Science and Technology Plan Project(No.YZ2023246).
文摘Because the volatile content of isoamyl alcohol increases sharply on the seventh day of wheat mildew infection,isoamyl alcohol can be used as an early biomarker of wheat mildew infection.Currently,only a few sensors for isoamyl alcohol detection have been reported,and these sensors still suffer from low sensitivity and poor moisture resistance.Herein,the isoamyl alcohol sensitivity of 5 at%Er@LaFeO_(3)(ELFO)was enhanced by loading Ag nanoparticles on the surface of the ELFO microspheres,while the optimal operating temperature was reduced.The moisture resistance of Ag/ELFO was improved by the incorporation of g-C_(3)N_(4)nanosheets(NSs)on the surface of Ag/ELFO through electrostatic self-assembly.Given the requirements for practical applications in grain granaries,the sensing behavior of a Ag/ELFO-based sensor incorporating g-C_(3)N_(4)NSs at 20%relative humidity(RH)was systematically studied,and the sensor demonstrated excellent repeatability,long-term stability,and superior selectivity(791 at 50 ppm)for isoamyl alcohol with a low limit of detection(LOD=75 ppb).Furthermore,the practical results obtained for wheat at different mildew stages further confirmed the potential of the g-C_(3)N_(4)/Ag/ELFO-based sensor for monitoring the early mildew stage of wheat.This work may offer guidance for enhancing the moisture resistance of gas-sensitive materials through the strategy of employing composite nanomaterials.
基金funded by the National Natural Science Foundation of China(No.22178153)National Key Research and Development Program of China(No.2021YFC2103800)Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘In this study,Candida rugosa lipase(CRL)was immobilized on the silica carrier SBA-15 by physical adsorption,then mixed with hydrophobically modified sodium alginate and dropped into calcium chloride solution.Finally,the adsorption-embedding immobilized lipase(L-SBA-15-Mgel)was successfully prepared.The conformation of the carrier before and after lipase immobilization were analyzed by scanning electron microscopy(SEM),thermogravimetric analysis(TGA),Fourier transform infrared spectroscopy(FT-IR)and other characterization techniques.The molecular docking and molecular dynamics simulation of CRL and modifier dodecyl glycidyl ether(DGE)ligand were carried out to analyze the potential influence of modifier on enzyme characteristics.The basic enzymatic properties including the activity,stability and reaction kinetic parameters of the immobilized lipase L-SBA-15-Mgel were studied.L-SBA-15-Mgel showed good storage stability and reusability.After 16 days of storage,the activity retention was 47.85%,and there was still 63.20%of the residual activity after seven cycles of reuse.The immobilized lipase was applied to the efficient synthesis of food flavor ester isoamyl acetate.Under the reaction conditions of 50℃ and 200 rpm,the highest yield of isoamyl acetate catalyzed by L-SBA-15-Mgel was 85.19%.
文摘Isoamyl acetate was catalytically synthesized by SnCl 4·5H 2O. The effects of reaction time, catalyst amount,and ratio of glacial acetic acid to isoamyl alcohol were investgated. The results showed that at condition of molar ratio of HAc to isoamyl alcohol=1∶1 08, that of SnCl 4·5H 2O to HAc=1∶100, 150 ℃, 1 h isoamyl acetate can be obtained in yield of 95 6%.
