Mass transfer performance of gas–liquid two-phase flow at microscale is the basis of application of microreactor in gas–liquid reaction systems.At present,few researches on the mass transfer property of annular flow...Mass transfer performance of gas–liquid two-phase flow at microscale is the basis of application of microreactor in gas–liquid reaction systems.At present,few researches on the mass transfer property of annular flow have been reported.Therefore,the mass transfer mechanism and relationship of gas–liquid annular flow in a microfluidic cross-junction device are studied in the present study.We find that the main factors,i.e.,flow pattern,liquid film thickness,liquid hydraulic retention time,phase interface fluctuation,and gas flow vorticity,which influence the flow mass transfer property,are directly affected both by gas and liquid flow velocities.But the influences of gas and liquid velocities on different mass transfer influencing factors are different.Thereout,the fitting relationships between gas and liquid flow velocities and mass transfer influencing factors are established.By comparing the results from calculations using fitting equations and simulations,it shows that the fitting equations have relatively high degrees of accuracy.Finally,the Pareto front,namely the Pareto optimal solution set,of gas and liquid velocity conditions for the best flow mass transfer property is obtained using the method of multi-objective particle swarm optimization.It is proved that the mass transfer property of the gas–liquid two-phase flow can be obviously enhanced under the guidance of the obtained Pareto optimal solution set through experimental verification.展开更多
AIM To determine the frequency and risk factors for colorectal cancer(CRC) development among individuals with resected advanced adenoma(AA)/traditional serrated adenoma(TSA)/advanced sessile serrated adenoma(ASSA). ME...AIM To determine the frequency and risk factors for colorectal cancer(CRC) development among individuals with resected advanced adenoma(AA)/traditional serrated adenoma(TSA)/advanced sessile serrated adenoma(ASSA). METHODS Data was collected from medical records of 14663 subjects found to have AA, TSA, or ASSA at screening or surveillance colonoscopy. Patients with inflammatory bowel disease or known genetic predisposition for CRC were excluded from the study. Factors associated with CRC developing after endoscopic management of high risk polyps were calculated in 4610 such patients who had at least one surveillance colonoscopy within 10 years following the original polypectomy of the incident advanced polyp. RESULTS84/4610(1.8%) patients developed CRC at the polypectomy site within a median of 4.2 years(mean 4.89 years), and 1.2%(54/4610) developed CRC in a region distinct from the AA/TSA/ASSA resection site within a median of 5.1 years(mean 6.67 years). Approximately, 30%(25/84) of patients who developed CRC at the AA/TSA/ASSA site and 27.8%(15/54) of patients who developed CRC at another site had colonoscopy at recommended surveillance intervals. Increasing age; polyp size; male sex; right-sided location; high degree of dysplasia; higher number of polyps resected; and piecemeal removal were associated with an increased risk for CRC developmentat the same site as the index polyp. Increasing age; right-sided location; higher number of polyps resected and sessile endoscopic appearance of the index AA/TSA/ASSA were significantly associated with an increased risk for CRC development at a different site. CONCLUSION Recognition that CRC may develop following AA/TSA/ASSA removal is one step toward improving our practice efficiency and preventing a portion of CRC related morbidity and mortality.展开更多
Zn/ZSM-5（NZ2） and Zn/Ni/ZSM-5（NZ3） as the catalysts for methanol to aromatics（MTA） were synthesized by a simple ultrasonic impregnation. The textural and acid properties of all catalysts were characterized using...Zn/ZSM-5（NZ2） and Zn/Ni/ZSM-5（NZ3） as the catalysts for methanol to aromatics（MTA） were synthesized by a simple ultrasonic impregnation. The textural and acid properties of all catalysts were characterized using XRD, HRTEM, NH;-TPD, Py-IR, XPS, XRF and TG techniques. The XRD and HRTEM results showed that the basic zeolite structures were not affected much with the incorporation of Zn and Ni species. However, great changes have taken place in acid properties. The Py-IR and XPS results indicated that the Zn-Lewis acid sites（ZnOH;species）, which have stronger interaction with the zeolite framework compared with ZnO species, were generated at the expense of B acid sites with the incorporation of zinc species. Moreover, the product analysis results showed that the incorporation of zinc species promoted the primary aromatization by enhancing the dehydroaromatization and suppressing the cracking and subsequent H-transfer reaction. Furthermore, the addition of Ni species well inhibited the loss of zinc species by converting partial ZnO species to ZnOH;species, and thus improved the aromatization activity and catalyst stability. The catalytic performance results showed that the NZ3 possess higher conversion of methanol in a longer time and lower average rate of coke formation compared with NZ2. In addition,the NZ3 also exhibited the highest yield of BTX as the reaction proceeds.展开更多
In the present work, core-shell Ni@SiO2 catalysts were investigated in order to evaluate the relevance of catalytic activity and surface states of Ni core as well as Ni nanoparticles size to catalytic partial oxidatio...In the present work, core-shell Ni@SiO2 catalysts were investigated in order to evaluate the relevance of catalytic activity and surface states of Ni core as well as Ni nanoparticles size to catalytic partial oxidation of methane （POM）. The catalysts were characterized by N2 adsorption, H2-TPR, XRD, TEM and XPS techniques. The catalytic performance of the core-shell catalysts was found to be dependent on the surface states of catalyst, which influenced the formation of products. It was considered that carbon dioxide formed on the oxidized nickel sites （NiO） and carbon monoxide produced on the reduced sites （Ni）. The surface states of active metal in the dynamic were influenced both by the size of Ni core and the porosity of silica shell. However, the catalytic activity would be debased when the size of Ni core was under a certain extent, which can be ascribed to the fact the carbon deposition increased with the increasing content of NiO. The effects of surface states of Ni@SiO2 catalyst on the catalytic performance were discussed and the reaction pathway over Ni core encapsulated inside silica shell was proposed.展开更多
OBJECTIVE:To evaluate evidence for the efficacy of Traditional Chinese Medicine(TCM) in systematic reviews.METHODS:Chinese(TCM Periodical Literature Database,Chinese Biological Medicine database,Chinese Medical Curren...OBJECTIVE:To evaluate evidence for the efficacy of Traditional Chinese Medicine(TCM) in systematic reviews.METHODS:Chinese(TCM Periodical Literature Database,Chinese Biological Medicine database,Chinese Medical Current Contents,China Hospital Knowledge Database journal fulltext database,Virtual Machining and Inspection System,and Wanfang) and English(Cochrane Database of Systematic Reviews,PubMed and Embase) databases were searched.RESULTS:Three thousand,nine hundred and fifty-five articles were initially identified,606 of which met the inclusion criteria,including 251 in English(83 from the Cochrane Database) and 355 in Chinese.The number of articles published each year increased between 1989 and 2009.Cardiocerebrovascular disease was the most studied target disease.Intervention measures included TCM preparations(177 articles),acupuncture(133 articles) and combinations of TCM and Western Medicine(38 articles).Control measures included positive medical(177 articles),basic treatment(100 articles),placebo(219 articles),and blank and mutual(107 articles).All articles included at least one reference;the greatest number was 268.Six of 10 articles with high quality references demonstrated curative effectsagainst target diseases including upper respiratory tract infection,dementia and depression.Interventions that were not recommended were tripterygium for rheumatoid arthritis and TCM syndrome differentiation for pediatric nocturia.In 10.4% of the studies,the authors concluded that the intervention had a curative effect.The assessors agreed with the authors' conclusions in 88.32% of cases,but rejected 8.94%(54 articles).CONCLUSION:1) Training in systematic review methods,including topic selection,study design,methods and technology,should be improved.2) Upper respiratory tract infection,dementia and depression may become the predominant diseases treated by TCM,and the corresponding interventions could be developed into practical applications.3) Use of non-recommended interventions should be controlled,and there should be more research on side effects.展开更多
This work is conducted to investigate the hierarchical structure, mechanical behavior and fracture resistance of grass carp scales with different water contents （hydrated and dehydrated） and load conditions （uniaxi...This work is conducted to investigate the hierarchical structure, mechanical behavior and fracture resistance of grass carp scales with different water contents （hydrated and dehydrated） and load conditions （uniaxial, biaxial and punch tests）. The whole cross-section of scales is investigated, and it is found that the bony layer displays discontinuity and partly embeds in collagen layer. Four different locations are considered under both tensile and punch tests. The results of the uniaxial tensile test show a correlation between the failure mode and the distribution of surface morphology on scales. The biaxial test results show that there are minor differences in the tensile strength and the Young＇ modulus compared with those of the uniaxial tests, but the ultimate strain is about 20% - 50%. Puncture tests are also conducted with different size of needles and different hardness silicon rubbers as substrate. The results show that the puncture force and deformation are dependent on the size of needle and the hardness of substrate. The failure pattern of scales is related to the water content. Radial cracks occur in the bony layer of hydrated scale, and the collagen fibers twist around the puncture site. However, the shear failure occurs in the bony layer of dehydrated scale.展开更多
Functional genomics employs dozens of OMICs technologies to explore the functions of DNA, RNA and protein regulators in gene regulation processes. Despite each of these technologies being powerful tools on their own, ...Functional genomics employs dozens of OMICs technologies to explore the functions of DNA, RNA and protein regulators in gene regulation processes. Despite each of these technologies being powerful tools on their own, fike the parable of blind men and an elephant, any one single technology has a limited ability to depict the complex regulatory system. Integrative OMICS approaches have emerged and become an important area in biology and medicine. It provides a precise and effective way to study gene regulations. Results： This article reviews current popular OMICs technologies, OMICs data integration strategies, and bioinformatics tools used for multi-dimensional data integration. We highlight the advantages of these methods, particularly in elucidating molecular basis of biological regulatory mechanisms. Conclusions： To better understand the complexity of biological processes, we need powerful bioinformatics tools to integrate these OMICs data. Integrating multi-dimensional OMICs data will generate novel insights into system-level gene regulations and serves as a foundation for further hypothesis-driven research.展开更多
基金the National Natural Science Foundation of China(22178241,21908152 and 21978189)State Key Laboratory of Chemical Engineering,China(SKL-ChE-21A01).
文摘Mass transfer performance of gas–liquid two-phase flow at microscale is the basis of application of microreactor in gas–liquid reaction systems.At present,few researches on the mass transfer property of annular flow have been reported.Therefore,the mass transfer mechanism and relationship of gas–liquid annular flow in a microfluidic cross-junction device are studied in the present study.We find that the main factors,i.e.,flow pattern,liquid film thickness,liquid hydraulic retention time,phase interface fluctuation,and gas flow vorticity,which influence the flow mass transfer property,are directly affected both by gas and liquid flow velocities.But the influences of gas and liquid velocities on different mass transfer influencing factors are different.Thereout,the fitting relationships between gas and liquid flow velocities and mass transfer influencing factors are established.By comparing the results from calculations using fitting equations and simulations,it shows that the fitting equations have relatively high degrees of accuracy.Finally,the Pareto front,namely the Pareto optimal solution set,of gas and liquid velocity conditions for the best flow mass transfer property is obtained using the method of multi-objective particle swarm optimization.It is proved that the mass transfer property of the gas–liquid two-phase flow can be obviously enhanced under the guidance of the obtained Pareto optimal solution set through experimental verification.
基金Supported by the National Cancer Institute,No.CA170357the Mayo Clinic Center for Cell Signaling in Gastroenterology,NIDDK Mo.P30DK084567
文摘AIM To determine the frequency and risk factors for colorectal cancer(CRC) development among individuals with resected advanced adenoma(AA)/traditional serrated adenoma(TSA)/advanced sessile serrated adenoma(ASSA). METHODS Data was collected from medical records of 14663 subjects found to have AA, TSA, or ASSA at screening or surveillance colonoscopy. Patients with inflammatory bowel disease or known genetic predisposition for CRC were excluded from the study. Factors associated with CRC developing after endoscopic management of high risk polyps were calculated in 4610 such patients who had at least one surveillance colonoscopy within 10 years following the original polypectomy of the incident advanced polyp. RESULTS84/4610(1.8%) patients developed CRC at the polypectomy site within a median of 4.2 years(mean 4.89 years), and 1.2%(54/4610) developed CRC in a region distinct from the AA/TSA/ASSA resection site within a median of 5.1 years(mean 6.67 years). Approximately, 30%(25/84) of patients who developed CRC at the AA/TSA/ASSA site and 27.8%(15/54) of patients who developed CRC at another site had colonoscopy at recommended surveillance intervals. Increasing age; polyp size; male sex; right-sided location; high degree of dysplasia; higher number of polyps resected; and piecemeal removal were associated with an increased risk for CRC developmentat the same site as the index polyp. Increasing age; right-sided location; higher number of polyps resected and sessile endoscopic appearance of the index AA/TSA/ASSA were significantly associated with an increased risk for CRC development at a different site. CONCLUSION Recognition that CRC may develop following AA/TSA/ASSA removal is one step toward improving our practice efficiency and preventing a portion of CRC related morbidity and mortality.
基金entrusted by the Project of "utilization of low rank coal" strategic leading special fundstrategic leading special fund of CAS (XDA-07070800 and XDA-07070400)the Opening Foundation of State Key Laboratory of Coal Conversion (J16-17-602)
文摘Zn/ZSM-5（NZ2） and Zn/Ni/ZSM-5（NZ3） as the catalysts for methanol to aromatics（MTA） were synthesized by a simple ultrasonic impregnation. The textural and acid properties of all catalysts were characterized using XRD, HRTEM, NH;-TPD, Py-IR, XPS, XRF and TG techniques. The XRD and HRTEM results showed that the basic zeolite structures were not affected much with the incorporation of Zn and Ni species. However, great changes have taken place in acid properties. The Py-IR and XPS results indicated that the Zn-Lewis acid sites（ZnOH;species）, which have stronger interaction with the zeolite framework compared with ZnO species, were generated at the expense of B acid sites with the incorporation of zinc species. Moreover, the product analysis results showed that the incorporation of zinc species promoted the primary aromatization by enhancing the dehydroaromatization and suppressing the cracking and subsequent H-transfer reaction. Furthermore, the addition of Ni species well inhibited the loss of zinc species by converting partial ZnO species to ZnOH;species, and thus improved the aromatization activity and catalyst stability. The catalytic performance results showed that the NZ3 possess higher conversion of methanol in a longer time and lower average rate of coke formation compared with NZ2. In addition,the NZ3 also exhibited the highest yield of BTX as the reaction proceeds.
基金supported by the Project of "Utilization of Low Rank Coal" Strategic Leading Special Fund.Chinese Academy of Sciences(XDA07070800)the Program of Overseas Science and Technology Activity(2012-35) and Shanxi Province and the Cooperation Program from Shanxi Fenxi Mining(Group)Co.,Ltd
文摘In the present work, core-shell Ni@SiO2 catalysts were investigated in order to evaluate the relevance of catalytic activity and surface states of Ni core as well as Ni nanoparticles size to catalytic partial oxidation of methane （POM）. The catalysts were characterized by N2 adsorption, H2-TPR, XRD, TEM and XPS techniques. The catalytic performance of the core-shell catalysts was found to be dependent on the surface states of catalyst, which influenced the formation of products. It was considered that carbon dioxide formed on the oxidized nickel sites （NiO） and carbon monoxide produced on the reduced sites （Ni）. The surface states of active metal in the dynamic were influenced both by the size of Ni core and the porosity of silica shell. However, the catalytic activity would be debased when the size of Ni core was under a certain extent, which can be ascribed to the fact the carbon deposition increased with the increasing content of NiO. The effects of surface states of Ni@SiO2 catalyst on the catalytic performance were discussed and the reaction pathway over Ni core encapsulated inside silica shell was proposed.
文摘OBJECTIVE:To evaluate evidence for the efficacy of Traditional Chinese Medicine(TCM) in systematic reviews.METHODS:Chinese(TCM Periodical Literature Database,Chinese Biological Medicine database,Chinese Medical Current Contents,China Hospital Knowledge Database journal fulltext database,Virtual Machining and Inspection System,and Wanfang) and English(Cochrane Database of Systematic Reviews,PubMed and Embase) databases were searched.RESULTS:Three thousand,nine hundred and fifty-five articles were initially identified,606 of which met the inclusion criteria,including 251 in English(83 from the Cochrane Database) and 355 in Chinese.The number of articles published each year increased between 1989 and 2009.Cardiocerebrovascular disease was the most studied target disease.Intervention measures included TCM preparations(177 articles),acupuncture(133 articles) and combinations of TCM and Western Medicine(38 articles).Control measures included positive medical(177 articles),basic treatment(100 articles),placebo(219 articles),and blank and mutual(107 articles).All articles included at least one reference;the greatest number was 268.Six of 10 articles with high quality references demonstrated curative effectsagainst target diseases including upper respiratory tract infection,dementia and depression.Interventions that were not recommended were tripterygium for rheumatoid arthritis and TCM syndrome differentiation for pediatric nocturia.In 10.4% of the studies,the authors concluded that the intervention had a curative effect.The assessors agreed with the authors' conclusions in 88.32% of cases,but rejected 8.94%(54 articles).CONCLUSION:1) Training in systematic review methods,including topic selection,study design,methods and technology,should be improved.2) Upper respiratory tract infection,dementia and depression may become the predominant diseases treated by TCM,and the corresponding interventions could be developed into practical applications.3) Use of non-recommended interventions should be controlled,and there should be more research on side effects.
文摘This work is conducted to investigate the hierarchical structure, mechanical behavior and fracture resistance of grass carp scales with different water contents （hydrated and dehydrated） and load conditions （uniaxial, biaxial and punch tests）. The whole cross-section of scales is investigated, and it is found that the bony layer displays discontinuity and partly embeds in collagen layer. Four different locations are considered under both tensile and punch tests. The results of the uniaxial tensile test show a correlation between the failure mode and the distribution of surface morphology on scales. The biaxial test results show that there are minor differences in the tensile strength and the Young＇ modulus compared with those of the uniaxial tests, but the ultimate strain is about 20% - 50%. Puncture tests are also conducted with different size of needles and different hardness silicon rubbers as substrate. The results show that the puncture force and deformation are dependent on the size of needle and the hardness of substrate. The failure pattern of scales is related to the water content. Radial cracks occur in the bony layer of hydrated scale, and the collagen fibers twist around the puncture site. However, the shear failure occurs in the bony layer of dehydrated scale.
基金Our work was supported by a Direct Grant for Research from The Chinese University of Hong Kong, Hong Kong SAR, China （No. 4053150） to JQ, research grants from Research Grants Council, Hong Kong SAR, China （No. 17121414M）, the National Natural Science Foundation of China （Nos. 81572786 and 91529303）, startup funds from Mayo Clinic （Mayo Clinic Arizona and Center for Individualized Medicine） to JW, and the National Natural Science Foundation of China （No. 11526144） and the Natural Science Foundation of Guangdong （No. 2016A030310038） to YH.
文摘Functional genomics employs dozens of OMICs technologies to explore the functions of DNA, RNA and protein regulators in gene regulation processes. Despite each of these technologies being powerful tools on their own, fike the parable of blind men and an elephant, any one single technology has a limited ability to depict the complex regulatory system. Integrative OMICS approaches have emerged and become an important area in biology and medicine. It provides a precise and effective way to study gene regulations. Results： This article reviews current popular OMICs technologies, OMICs data integration strategies, and bioinformatics tools used for multi-dimensional data integration. We highlight the advantages of these methods, particularly in elucidating molecular basis of biological regulatory mechanisms. Conclusions： To better understand the complexity of biological processes, we need powerful bioinformatics tools to integrate these OMICs data. Integrating multi-dimensional OMICs data will generate novel insights into system-level gene regulations and serves as a foundation for further hypothesis-driven research.
