Ionizing radiation can cause changes in nervous system function.However,the underlying mechanism remains unclear.In this study,Coenorhabditis elegans(C.elegans)was irradiated with 75 Gy of ^(60)Co whole-body γ radiat...Ionizing radiation can cause changes in nervous system function.However,the underlying mechanism remains unclear.In this study,Coenorhabditis elegans(C.elegans)was irradiated with 75 Gy of ^(60)Co whole-body γ radiation.Behavioral indicators(head thrashes,touch avoidance,and foraging),and the development of dopaminergic neurons related to behavioral function,were evaluated to assess the effects of ionizing radiation on nervous system function in C.elegans.Various behaviors were impaired after whole-body irradiation and degeneration of dopamine neurons was observed.This suggests that 75 Gy of γ radiation is sufficient to induce nervous system dysfunction.The genes nhr-76 and crm-1,which are reported to be related to nervous system function in human and mouse,were screened by transcriptome sequencing and bioinformatics analysis after irradiation or sham irradiation.The expression levels of these two genes were increased after radiation.Next,RNAi technology was used to inhibit the expression of crm-1,a gene whose homologs are associated with motor neuron development in other species.Downregulation of crm-1 expression effectively alleviated the deleterious effects of ionizing radiation on head thrashes and touch avoidance.It was also found that the expression level of crm-1 was regulated by the nuclear receptor gene nhr-76.The results of this study suggest that knocking down the expression level of nhr-76 can reduce the expression level of crm-1,while down-regulating the expression level of crm-1 can alleviate behavioral disorders induced by ionizing radiation.Therefore,inhibition of crm-1 may be of interest as a potential therapeutic target for ionizing radiation-induced neurological dysfunction.展开更多
As a chronic inflammatory disease of the liver,the pathogenic mechanisms of autoimmune hepatitis (AIH) have not yet been elucidated,with prognosis and diagnosis remaining unsatisfied.Currently the only viable treatmen...As a chronic inflammatory disease of the liver,the pathogenic mechanisms of autoimmune hepatitis (AIH) have not yet been elucidated,with prognosis and diagnosis remaining unsatisfied.Currently the only viable treatments of AIH are immunosuppressant application and liver transplantation.It is considered that lack of good animal AIH models is the main reason for the shortage of a simple and efficient cure.The Concanavalin A (Con A) model is a typical and well established model for investigating T-cell and macrophage dependent liver injury in mice,which closely mimics the pathogenesis mechanisms and pathological changes of patients,and is regarded as the best experimental model for AIH research so far.In this paper we eluci-dated the pathogenic mechanisms of AIH and the evolution of relative animal models.We go on to further focus on Con A-induced liver injury from the point of immunological mechanisms and the change of cytokine levels.Finally,we manifested the clinical significance of the AIH animal models and the challenges they would meet during their future development.展开更多
Serum enzymes that play potential roles in tumor growth have recently been reported to have prognostic relevance in a diverse array of tumors.However,prognosis-related serum enzymes are rarely reported for nasopharyng...Serum enzymes that play potential roles in tumor growth have recently been reported to have prognostic relevance in a diverse array of tumors.However,prognosis-related serum enzymes are rarely reported for nasopharyngeal carcinoma(NPC).To clarify whether the level of serum enzymes is linked to the prognosis of NPC,we reviewed the pretreatment data of lactate dehydrogenase(LDH),alkaline phosphatase (ALP),and glutamyl transferase (GGT) in 533 newly diagnosed NPC patients who underwent radical radiotherapy between May 2002 and October 2003 at Sun Yat-sen University Cancer Center.Patients were grouped according to the upper limit of normal values of LDH,ALP,and GGT.The Kaplan-Meier method and log-rank test were used for selecting prognostic factors from clinical characteristics and serum enzymes,and the chi-square test was applied to analyze the relationships of clinical characteristics and serum enzymes.Finally,a Cox proportional hazards model was used to identify the independent prognostic factors.We found that increased levels of LDH had poor effects on both overall survival and distant metastasis-free survival(P=0.009 and 0.035,respectively),and increased pretreatment level of serum ALP had poor effects on both overall survival and local recurrence-free survival(P=0.037 and 0.039,respectively).In multivariate analysis,increased LDH level was identified as an independent prognostic factor for overall survival.Therefore,we conclude that increased pretreatment serum LDH and ALP levels are poor prognostic factors for NPC.展开更多
当今医学研究透明化概念备受关注。通过研究注册,向社会公开研究方案的概况及具体信息,可提高研究质量和透明度。当前可进行指南注册的机构主要为国际实践指南注册与透明化平台(Practice Guideline REgistration for TransPAREncy,PREPA...当今医学研究透明化概念备受关注。通过研究注册,向社会公开研究方案的概况及具体信息,可提高研究质量和透明度。当前可进行指南注册的机构主要为国际实践指南注册与透明化平台(Practice Guideline REgistration for TransPAREncy,PREPARE);系统评价/Meta分析注册机构主要有Cochrane协作网、PROSPERO(International Prospective Register of Systematic Reviews,PROSPERO)国际化注册平台、JBI(Joanna Briggs Institute,JBI)循证卫生保健中心、Campbell协作网、环境证据协作网(The Collaboration for Environmental Evidence,CEE)以及最新启动使用的INPLASY(International Platform of Registered Systematic Review and Meta-analysis Protocols,INPLASY)注册平台。本文介绍了上述各平台的基本信息,以及不同系统评价/Meta分析注册平台之间的异同,为相关科研工作者提供参考。展开更多
Introduction:Thrombocytosis has been identified as an unfavorable prognostic factor in several types of cancer.This study aimed to evaluate the prognostic value of pretreatment platelet count in association with the T...Introduction:Thrombocytosis has been identified as an unfavorable prognostic factor in several types of cancer.This study aimed to evaluate the prognostic value of pretreatment platelet count in association with the TNM staging system and therapeutic regimens in patients with nasopharyngeal carcinoma(NPC).Methods:A total of 2,626 patients with NPC were retrospectively analyzed.Platelet count >300 × 10~9/L was defined as thrombocytosis.Matched-pair analysis was performed between patients receiving chemoradiotherapy and radiotherapy.Results:Multivariate analysis showed that platelet count was an independent unfavorable prognostic factor for overall survival(OS)[hazard ratio(HR) = 1.810,95%confidence interval(CI) = 1.531-2.140,P < 0.001]and distant metastasis-free survival(DMFS)(HR = 1.873,95%CI = 1.475-2.379,P < 0.001) in the entire patient cohort.Further subgroup analysis revealed that increased platelet count was an independent unfavorable prognostic factor for OS and DMFS in patients with NPC stratified by early and advanced T category,N category,or TNM classification(all P < 0.001).Receiver operating characteristic(ROC) curves verified that the predictive value of TNM classification for OS was improved when combined with pretreatment platelet count(P = 0.030).Matched-pair analysis showed that chemoradiotherapy significantly improved OS only in advanced-stage NPC with thrombocytosis(HR = 0.416,95%CI = 0.226-0.765,P = 0.005).Conclusions:Pretreatment platelet count,when combined with TNM classification,is a useful indicator for metastasis and survival in patients with NPC.It may improve the predictive value of the TNM classification and help to identify patients likely to benefit from more aggressive therapeutic regimens.展开更多
In response to the awareness of limited fossil resources and environmental concerns,catalytic conversion of renewable lignocellulose biomass to value-added chemicals and fuels is of great significance and attractive f...In response to the awareness of limited fossil resources and environmental concerns,catalytic conversion of renewable lignocellulose biomass to value-added chemicals and fuels is of great significance and attractive for sustainable chemistry.Division of Biomass Conversion and Bio-Energy attached to Dalian National Laboratory for Clean Energy has devoted themselves to valorization of lignocellulose biomass since launched in 2011.Our research interests focus on breeding of biomass resources(inulin and microalgae),exploration of catalytic and biological technologies,and production of energy chemicals and fuels.Although lignocellulose biomass is renewable and abundant,the way of utilization should be reasonable according to its structural characteristics in view of efficiency and economy.In this review,to celebrate the DICP's 70 th anniversary,we will highlight the major fundamental advances in DICP about the conversion of lignocellulose to value-added chemicals and liquid fuels.Particular attention will be paid to the transformation of cellulose and its derivatives to glycols,acids and nitrogen-containing chemicals,hemicellulose-derived platform molecule furfural to jet fuels and lignin to aromatics using catalytic technologies.展开更多
Direct conversion of fructose-based carbohydrates to 5-ethoxymethylfurfural (EMF) catalyzed by Lewis acid in ethanol was investigated. It was found that BF3(Et)2O was favorable for 5-hydroxymethylfurfural (HMF) etheri...Direct conversion of fructose-based carbohydrates to 5-ethoxymethylfurfural (EMF) catalyzed by Lewis acid in ethanol was investigated. It was found that BF3(Et)2O was favorable for 5-hydroxymethylfurfural (HMF) etherification to EMF. BF3(Et)2O combination with AlCl3 6H2O with the molar ratio of 1 was an effective catalyst system for synthesis of EMF from fructose-based carbohydrates. 55.0%, 45.4% and 23.9% of EMF yields were obtained from fructose, inulin and sucrose under optimized conditions, respectively.展开更多
Objective: In our previous work, we incorporated complete blood count(CBC) into TNM stage to develop a new prognostic score model, which was validated to improve prediction efficiency of TNM stage for nasopharyngeal c...Objective: In our previous work, we incorporated complete blood count(CBC) into TNM stage to develop a new prognostic score model, which was validated to improve prediction efficiency of TNM stage for nasopharyngeal carcinoma(NPC).The purpose of this study was to revalidate the accuracy of the model, and its superiority to TNM stage, through data from a prospective study.Methods: CBC of 249 eligible patients from the 863 Program No.2006AA02Z4B4 was evaluated.Prognostic index(PI) of each patient was calculated according to the score model.Then they were divided by the PI into three categories: the low-, intermediate-and high-risk patients.The 5-year disease-specific survival(DSS) of the three categories was compared by a log-rank test.The model and TNM stage(7th edition) were compared on efficiency for predicting the 5-year DSS, through comparison of the area under curve(AUC) of their receiver-operating characteristic curves.Results: The 5-year DSS of the low-, intermediate- and high-risk patients were 96.0%, 79.1% and 62.2%,respectively.The low- and intermediate-risk patients had better DSS than the high-risk patients(P<0.001 and P<0.005, respectively).And there was a trend of better DSS in the low-risk patients, compared with the intermediate-risk patients(P=0.049).The AUC of the model was larger than that of TNM stage(0.726 vs.0.661,P=0.023).Conclusions: A CBC-based prognostic score model was revalidated to be accurate and superior to TNM stage on predicting 5-year DSS of NPC.展开更多
Glycerol can be obtained as a by-product during biodiesel manufacture. It is important to convert glycerol to value-added products. Glycerol esterification with acetic acid is one of the most promising approaches for ...Glycerol can be obtained as a by-product during biodiesel manufacture. It is important to convert glycerol to value-added products. Glycerol esterification with acetic acid is one of the most promising approaches for glycerol utilization. It is usually difficult to obtain diacetin with good activity and selectivity. In this work, glycerol esterification with acetic acid over different metal oxides, such as Bi2O3, Sb2O3, Sn O2, Ti O2, Nb2O5 and Sb2O5, was investigated. It was found that in the six investigated metal oxides, only Sb2O5 resulted in good activity and selectivity to diacetin. Under the optimized conditions, the glycerol conversion reached 96.8%,and the selectivity to diacetin reached 54.2%, while the selectivity to monoacetin and triacetin was 33.2% and12.6%, respectively. The catalysts were characterized with FT-IR spectra of adsorbed pyridine, which indicated that in the six investigated metal oxides, only Sb2O5 possessed Br?nsted acid sites strong enough to protonate adsorbed pyridine. The good catalytic activity and selectivity to diacetin might be mainly attributable to the Br?nsted acid sites of Sb2O5. Reusability tests showed that with Sb2O5 as catalyst, after six reaction cycles, no significant change in the glycerol conversion and the selectivity to diacetin was observed.展开更多
Efficient catalytic oxidation of ethylbenzene to acetophenone was realized using the catalytic system of cobalt zeolitic imidazolate framework ZIF-67/N-hydroxyphthalimide(NHPI) under mild conditions. 95.2% conversion ...Efficient catalytic oxidation of ethylbenzene to acetophenone was realized using the catalytic system of cobalt zeolitic imidazolate framework ZIF-67/N-hydroxyphthalimide(NHPI) under mild conditions. 95.2% conversion of ethylbenzene with 90.3% selectivity to acetophenone could be obtained at 373 K under 0.3 MPa O2 for 9 h. The results show that there exists synergetic effect between ZIF-67 and NHPI. 1-Phenylethyl hydroperoxide(PEHP) was generated via a radical process involving the hydrogen abstraction from ethylbenzene by phthalimide N-oxyl, and subsequently effectively decomposed to acetophenone by ZIF-67.展开更多
In the recent 50 years,marine oil spills had resulted in severe environmental pollution problems worldwide.In this study,12 petroleum-degrading strains named MJ1 to MJ12,which can use diesel oil as the sole carbon sou...In the recent 50 years,marine oil spills had resulted in severe environmental pollution problems worldwide.In this study,12 petroleum-degrading strains named MJ1 to MJ12,which can use diesel oil as the sole carbon source for growth,were isolated from the seawater in Jiaozhou Bay,China.Strain MJ4 has the highest diesel-degrading rate which is up to 26.54%in 5 days with the diesel oil concentration of 10 g/L.According to the BLAST research,16SrRNA sequence of MJ4 showed 99%similarity to Bacillus megaterium strain.Single-factor experiments and response surface methodology were carried out to optimize the environmental factors and their reciprocal action for affecting the diesel oil degradation process of Bacillus sp.MJ4.Results of single-factor experiments revealed that the highest degradation rate was obtained with temperature of 28°C,pH of 8.8,diesel oil concentration of 25 g/L,P/N ratio of 0.56,nitrogen and phosphorus dosage quantity of 0.35 g/L and 0.18 g/L,respectively.A nonlinear regression equation of diesel oil degradation rate and pH,temperature,P/N ratio was obtained.The model predicted the maximum degradation rate of 72.21%with temperature of 28°C,pH of 8.88,P/N ratio of 0.31,respectively.展开更多
基金supported by the National Natural Science Foundation of China,Nos.82003391(to NC),U1867204(to YT)the Natural Science Research Projects of Colleges and Universities in Jiangsu Province,No.20KJB310007(to NC).
文摘Ionizing radiation can cause changes in nervous system function.However,the underlying mechanism remains unclear.In this study,Coenorhabditis elegans(C.elegans)was irradiated with 75 Gy of ^(60)Co whole-body γ radiation.Behavioral indicators(head thrashes,touch avoidance,and foraging),and the development of dopaminergic neurons related to behavioral function,were evaluated to assess the effects of ionizing radiation on nervous system function in C.elegans.Various behaviors were impaired after whole-body irradiation and degeneration of dopamine neurons was observed.This suggests that 75 Gy of γ radiation is sufficient to induce nervous system dysfunction.The genes nhr-76 and crm-1,which are reported to be related to nervous system function in human and mouse,were screened by transcriptome sequencing and bioinformatics analysis after irradiation or sham irradiation.The expression levels of these two genes were increased after radiation.Next,RNAi technology was used to inhibit the expression of crm-1,a gene whose homologs are associated with motor neuron development in other species.Downregulation of crm-1 expression effectively alleviated the deleterious effects of ionizing radiation on head thrashes and touch avoidance.It was also found that the expression level of crm-1 was regulated by the nuclear receptor gene nhr-76.The results of this study suggest that knocking down the expression level of nhr-76 can reduce the expression level of crm-1,while down-regulating the expression level of crm-1 can alleviate behavioral disorders induced by ionizing radiation.Therefore,inhibition of crm-1 may be of interest as a potential therapeutic target for ionizing radiation-induced neurological dysfunction.
基金Supported by Program for Excellent Talents of Anhui Province,No.2006JQ1196
文摘As a chronic inflammatory disease of the liver,the pathogenic mechanisms of autoimmune hepatitis (AIH) have not yet been elucidated,with prognosis and diagnosis remaining unsatisfied.Currently the only viable treatments of AIH are immunosuppressant application and liver transplantation.It is considered that lack of good animal AIH models is the main reason for the shortage of a simple and efficient cure.The Concanavalin A (Con A) model is a typical and well established model for investigating T-cell and macrophage dependent liver injury in mice,which closely mimics the pathogenesis mechanisms and pathological changes of patients,and is regarded as the best experimental model for AIH research so far.In this paper we eluci-dated the pathogenic mechanisms of AIH and the evolution of relative animal models.We go on to further focus on Con A-induced liver injury from the point of immunological mechanisms and the change of cytokine levels.Finally,we manifested the clinical significance of the AIH animal models and the challenges they would meet during their future development.
基金supported by grant from Hi-Tech Research and Development Program of China(No.2006AA02Z4B4)
文摘Serum enzymes that play potential roles in tumor growth have recently been reported to have prognostic relevance in a diverse array of tumors.However,prognosis-related serum enzymes are rarely reported for nasopharyngeal carcinoma(NPC).To clarify whether the level of serum enzymes is linked to the prognosis of NPC,we reviewed the pretreatment data of lactate dehydrogenase(LDH),alkaline phosphatase (ALP),and glutamyl transferase (GGT) in 533 newly diagnosed NPC patients who underwent radical radiotherapy between May 2002 and October 2003 at Sun Yat-sen University Cancer Center.Patients were grouped according to the upper limit of normal values of LDH,ALP,and GGT.The Kaplan-Meier method and log-rank test were used for selecting prognostic factors from clinical characteristics and serum enzymes,and the chi-square test was applied to analyze the relationships of clinical characteristics and serum enzymes.Finally,a Cox proportional hazards model was used to identify the independent prognostic factors.We found that increased levels of LDH had poor effects on both overall survival and distant metastasis-free survival(P=0.009 and 0.035,respectively),and increased pretreatment level of serum ALP had poor effects on both overall survival and local recurrence-free survival(P=0.037 and 0.039,respectively).In multivariate analysis,increased LDH level was identified as an independent prognostic factor for overall survival.Therefore,we conclude that increased pretreatment serum LDH and ALP levels are poor prognostic factors for NPC.
基金supported by the National Natural Science Foundation of China (21790331,21603218)the Strategic Priority Research Program of Chinese Academy of Sciences (XDA21030400,XDB17020300)~~
文摘当今医学研究透明化概念备受关注。通过研究注册,向社会公开研究方案的概况及具体信息,可提高研究质量和透明度。当前可进行指南注册的机构主要为国际实践指南注册与透明化平台(Practice Guideline REgistration for TransPAREncy,PREPARE);系统评价/Meta分析注册机构主要有Cochrane协作网、PROSPERO(International Prospective Register of Systematic Reviews,PROSPERO)国际化注册平台、JBI(Joanna Briggs Institute,JBI)循证卫生保健中心、Campbell协作网、环境证据协作网(The Collaboration for Environmental Evidence,CEE)以及最新启动使用的INPLASY(International Platform of Registered Systematic Review and Meta-analysis Protocols,INPLASY)注册平台。本文介绍了上述各平台的基本信息,以及不同系统评价/Meta分析注册平台之间的异同,为相关科研工作者提供参考。
基金supported by grants from the Hi-Tech Research and Development Program of China(No.2006AA02Z4B4)the National Natural Science Foundation of China(No.30770641No.31170805)
文摘Introduction:Thrombocytosis has been identified as an unfavorable prognostic factor in several types of cancer.This study aimed to evaluate the prognostic value of pretreatment platelet count in association with the TNM staging system and therapeutic regimens in patients with nasopharyngeal carcinoma(NPC).Methods:A total of 2,626 patients with NPC were retrospectively analyzed.Platelet count >300 × 10~9/L was defined as thrombocytosis.Matched-pair analysis was performed between patients receiving chemoradiotherapy and radiotherapy.Results:Multivariate analysis showed that platelet count was an independent unfavorable prognostic factor for overall survival(OS)[hazard ratio(HR) = 1.810,95%confidence interval(CI) = 1.531-2.140,P < 0.001]and distant metastasis-free survival(DMFS)(HR = 1.873,95%CI = 1.475-2.379,P < 0.001) in the entire patient cohort.Further subgroup analysis revealed that increased platelet count was an independent unfavorable prognostic factor for OS and DMFS in patients with NPC stratified by early and advanced T category,N category,or TNM classification(all P < 0.001).Receiver operating characteristic(ROC) curves verified that the predictive value of TNM classification for OS was improved when combined with pretreatment platelet count(P = 0.030).Matched-pair analysis showed that chemoradiotherapy significantly improved OS only in advanced-stage NPC with thrombocytosis(HR = 0.416,95%CI = 0.226-0.765,P = 0.005).Conclusions:Pretreatment platelet count,when combined with TNM classification,is a useful indicator for metastasis and survival in patients with NPC.It may improve the predictive value of the TNM classification and help to identify patients likely to benefit from more aggressive therapeutic regimens.
基金supported by the National Natural Science Foundation of China(Projects 21790331,21603218,21703236 and 21872138)the Strategic Priority Research Program of the Chinese Academy of Sciences(Nos.XDB17020300 and XDA21030400)+1 种基金the Youth Innovation Promotion Association,CAS(2018219)DICP ZZBS201811
文摘In response to the awareness of limited fossil resources and environmental concerns,catalytic conversion of renewable lignocellulose biomass to value-added chemicals and fuels is of great significance and attractive for sustainable chemistry.Division of Biomass Conversion and Bio-Energy attached to Dalian National Laboratory for Clean Energy has devoted themselves to valorization of lignocellulose biomass since launched in 2011.Our research interests focus on breeding of biomass resources(inulin and microalgae),exploration of catalytic and biological technologies,and production of energy chemicals and fuels.Although lignocellulose biomass is renewable and abundant,the way of utilization should be reasonable according to its structural characteristics in view of efficiency and economy.In this review,to celebrate the DICP's 70 th anniversary,we will highlight the major fundamental advances in DICP about the conversion of lignocellulose to value-added chemicals and liquid fuels.Particular attention will be paid to the transformation of cellulose and its derivatives to glycols,acids and nitrogen-containing chemicals,hemicellulose-derived platform molecule furfural to jet fuels and lignin to aromatics using catalytic technologies.
基金the National Natural Science Foundation of China(21233008 and 21203180)
文摘Direct conversion of fructose-based carbohydrates to 5-ethoxymethylfurfural (EMF) catalyzed by Lewis acid in ethanol was investigated. It was found that BF3(Et)2O was favorable for 5-hydroxymethylfurfural (HMF) etherification to EMF. BF3(Et)2O combination with AlCl3 6H2O with the molar ratio of 1 was an effective catalyst system for synthesis of EMF from fructose-based carbohydrates. 55.0%, 45.4% and 23.9% of EMF yields were obtained from fructose, inulin and sucrose under optimized conditions, respectively.
基金supported by Hi-Tech Research and Development Program of China (863 Program) (No.2006AA02Z4B4)
文摘Objective: In our previous work, we incorporated complete blood count(CBC) into TNM stage to develop a new prognostic score model, which was validated to improve prediction efficiency of TNM stage for nasopharyngeal carcinoma(NPC).The purpose of this study was to revalidate the accuracy of the model, and its superiority to TNM stage, through data from a prospective study.Methods: CBC of 249 eligible patients from the 863 Program No.2006AA02Z4B4 was evaluated.Prognostic index(PI) of each patient was calculated according to the score model.Then they were divided by the PI into three categories: the low-, intermediate-and high-risk patients.The 5-year disease-specific survival(DSS) of the three categories was compared by a log-rank test.The model and TNM stage(7th edition) were compared on efficiency for predicting the 5-year DSS, through comparison of the area under curve(AUC) of their receiver-operating characteristic curves.Results: The 5-year DSS of the low-, intermediate- and high-risk patients were 96.0%, 79.1% and 62.2%,respectively.The low- and intermediate-risk patients had better DSS than the high-risk patients(P<0.001 and P<0.005, respectively).And there was a trend of better DSS in the low-risk patients, compared with the intermediate-risk patients(P=0.049).The AUC of the model was larger than that of TNM stage(0.726 vs.0.661,P=0.023).Conclusions: A CBC-based prognostic score model was revalidated to be accurate and superior to TNM stage on predicting 5-year DSS of NPC.
基金supported by the"Strategic Priority Research Program-Climate Change:Carbon Budget and Related Issues"of the Chinese Academy of Sciences(XDA050102)the National Natural Science Foundation of China(21233008)
文摘Glycerol can be obtained as a by-product during biodiesel manufacture. It is important to convert glycerol to value-added products. Glycerol esterification with acetic acid is one of the most promising approaches for glycerol utilization. It is usually difficult to obtain diacetin with good activity and selectivity. In this work, glycerol esterification with acetic acid over different metal oxides, such as Bi2O3, Sb2O3, Sn O2, Ti O2, Nb2O5 and Sb2O5, was investigated. It was found that in the six investigated metal oxides, only Sb2O5 resulted in good activity and selectivity to diacetin. Under the optimized conditions, the glycerol conversion reached 96.8%,and the selectivity to diacetin reached 54.2%, while the selectivity to monoacetin and triacetin was 33.2% and12.6%, respectively. The catalysts were characterized with FT-IR spectra of adsorbed pyridine, which indicated that in the six investigated metal oxides, only Sb2O5 possessed Br?nsted acid sites strong enough to protonate adsorbed pyridine. The good catalytic activity and selectivity to diacetin might be mainly attributable to the Br?nsted acid sites of Sb2O5. Reusability tests showed that with Sb2O5 as catalyst, after six reaction cycles, no significant change in the glycerol conversion and the selectivity to diacetin was observed.
基金supported by the National Natural Science Foundation of China(21233008,21103175 and 20803074)the"Strategic Priority Research Program-Climate Change:Carbon Budget and Related Issues"of the Chinese Academy of Sciences(XDA05010203)
文摘Efficient catalytic oxidation of ethylbenzene to acetophenone was realized using the catalytic system of cobalt zeolitic imidazolate framework ZIF-67/N-hydroxyphthalimide(NHPI) under mild conditions. 95.2% conversion of ethylbenzene with 90.3% selectivity to acetophenone could be obtained at 373 K under 0.3 MPa O2 for 9 h. The results show that there exists synergetic effect between ZIF-67 and NHPI. 1-Phenylethyl hydroperoxide(PEHP) was generated via a radical process involving the hydrogen abstraction from ethylbenzene by phthalimide N-oxyl, and subsequently effectively decomposed to acetophenone by ZIF-67.
基金This work was supported by the Scientific Research Foundation of Shandong University of Science and Technology under Grant for Recruited Talents[2014RCJJ015]Project of Shandong Province Higher Educational Young Innovative Talent Introduction and Cultivation Team[Hydrogen energy chemistry innovation team]and the Science and Technology Projects of Qingdao(Grant No.19-6-2-25-cg)。
文摘In the recent 50 years,marine oil spills had resulted in severe environmental pollution problems worldwide.In this study,12 petroleum-degrading strains named MJ1 to MJ12,which can use diesel oil as the sole carbon source for growth,were isolated from the seawater in Jiaozhou Bay,China.Strain MJ4 has the highest diesel-degrading rate which is up to 26.54%in 5 days with the diesel oil concentration of 10 g/L.According to the BLAST research,16SrRNA sequence of MJ4 showed 99%similarity to Bacillus megaterium strain.Single-factor experiments and response surface methodology were carried out to optimize the environmental factors and their reciprocal action for affecting the diesel oil degradation process of Bacillus sp.MJ4.Results of single-factor experiments revealed that the highest degradation rate was obtained with temperature of 28°C,pH of 8.8,diesel oil concentration of 25 g/L,P/N ratio of 0.56,nitrogen and phosphorus dosage quantity of 0.35 g/L and 0.18 g/L,respectively.A nonlinear regression equation of diesel oil degradation rate and pH,temperature,P/N ratio was obtained.The model predicted the maximum degradation rate of 72.21%with temperature of 28°C,pH of 8.88,P/N ratio of 0.31,respectively.
