Since the early 20th century,China has gradually established a clinical,educational,and research system centered around modern scientific medicine,which has now become the dominant force in China's medical and hea...Since the early 20th century,China has gradually established a clinical,educational,and research system centered around modern scientific medicine,which has now become the dominant force in China's medical and health system and services,with the construction and development of the Chinese Academy of Medical Sciences and Peking Union Medical College as the most prominent symbol.The scientific medicine in the new era requires close cooperation across multiple disciplines and fields to build a high-quality and efficient medical and health service system.It also involves combining the excellent traditional Chinese culture with Western medicine to explore a unique path of modern scientific medicine with Chinese characteristics.展开更多
Recent years have witnessed a dynamic develop of Peking Union Medical College(PUMC),which was founded in 1921,and Chinese Academy of Medical Sciences(CAMS),which was founded in 1956.In the new era of building a"H...Recent years have witnessed a dynamic develop of Peking Union Medical College(PUMC),which was founded in 1921,and Chinese Academy of Medical Sciences(CAMS),which was founded in 1956.In the new era of building a"Healthy China",General Secretary Xi Jinping has emphasized the importance of a profound understanding of the Chinese civilization to let the world better know and understand China,and urged efforts to combine theories and practices to expound how to better uphold the Chinese path,promote the Chinese spirit,and pool together the Chinese strength[1].As an active response,PUMC organized the first Conference of History of Medicine on May 20-21,2023[2],Based on the rich history of PUMC and with an attempt to explore history,inherit the traditional Chinese culture,and promote the spirit of modern medicine,we issued the following call at the conference。展开更多
AIM: To investigate dynamic characteristics and pathological mechanism of signal in rabbit VX-2 tumor model on diffusion-weighted imaging (DWI) after chemoembolization. METHODS: Forty New Zealand rabbits were included...AIM: To investigate dynamic characteristics and pathological mechanism of signal in rabbit VX-2 tumor model on diffusion-weighted imaging (DWI) after chemoembolization. METHODS: Forty New Zealand rabbits were included in the study and forty-seven rabbit VX-2 tumor models were raised by implanting directly and intrahepatically after abdominal cavity opened. Forty VX-2 tumor models from them were divided into four groups. DWI was performed periodically and respectively for each group after chemoembolization. All VX-2 tumor samples of each group were studied by pathology. The distinction of VX-2 tumors on DWI was assessed by their apparent diffusion coefficient (ADC) values. The statistical significance between different time groups, different area groups or different b-value groups was calculated by using SPSS12.0 software. RESULTS: Under b-value of 100 s/mm2, ADC values were lowest at 16 h after chemoembolization in area of VX-2 tumor periphery, central, and normal liver parenchyma around tumor, but turned to increase with further elongation of chemoembolization treatment. The distinction of ADC between different time groups was significant respectively (F = 7.325, P < 0.001; F = 2.496, P < 0.048; F = 6.856, P < 0.001). Cellular edema in the area of VX-2 tumor periphery or normal liver parenchyma around tumor, increased quickly in sixteen h after chemoembolization but, from the 16th h to the 48th h, cellular edema in the area of normal liver parenchyma around tumor decreased gradually and that in the area of VX-2 tumor periphery decreased lightly at, and then increased continually. After chemoembolization, Cellular necrosis in the area of VX-2 tumor periphery was more significantly high than that before chemoembolization. The areas of dead cells in VX-2 tumors manifested low signal and high ADC value, while the areas of viable cells manifested high signal and low ADC value. CONCLUSION: DWI is able to detect and differentiate tumor necrotic areas from viable cellular areas before and after chemoembolization. ADC of normal liver parenchyma and VX-2 tumor are influenced by intracellular edema, tissue cellular death and microcirculation disturbance after chemoembolization.展开更多
As for ceramic stereolithography technique,the preparation of suitable resin-based ceramic slurry is of primary importance.In this study,the effects of powder characteristics such as specific surface area,particle siz...As for ceramic stereolithography technique,the preparation of suitable resin-based ceramic slurry is of primary importance.In this study,the effects of powder characteristics such as specific surface area,particle size and distribution,particle morphology on the rheological behavior of zirconia resin-based suspensions were investigated intensively.Results show that the specific surface area of the powder is the most important factor affecting slurry viscosity.Choosing low specific surface area and quasi-spherical shaped powder is more likely to obtain low viscosity slurries.In addition,the influence of solid loading on the flow behavior were also studied using Krieger-Dougherty model.Zirconia samples with the relative density of(97.83±0.33)%were obtained after sintering at 1550℃.No obvious abnormal grain growth in the microstructure of the sintered body is observed.Results indicate that after the optimization of the processing parameters with the help of rheology characterization,complex-shaped high-quality zirconia parts can be obtained using the stereolithography technique.展开更多
AIM: To investigate the dynamic characteristics and the correlation between PCNA, Bax, nm23, E-cadherin expression and apparent diffusion coefficient (ADC) on MR diffusion-weighted imaging (DWI) after chemoembolizatio...AIM: To investigate the dynamic characteristics and the correlation between PCNA, Bax, nm23, E-cadherin expression and apparent diffusion coefficient (ADC) on MR diffusion-weighted imaging (DWI) after chemoembolization in rabbit liver VX-2 tumor model. METHODS: Forty New Zealand rabbit liver VX-2 tumor models were included in the study. DWI was carried out periodically after chemoembolization. All VX-2 tumor samples in each group were examined by histopathology and Strept Avidin-Biotin Complex (SABC) immunohistochemical staining. RESULTS: The PCNA expression index in VX-2 tumors was higher than in the normal parenchyma around the tumor (P < 0.001). Nm23, Bax or E-caderin expression index in VX-2 tumors were lower than in the normal parenchyma around the tumor (all P < 0.001). PCNAand nm23 expression in the VX-2 tumor periphery first increased and then decreased (P < 0.001 and P = 0.03, respectively), while the expression of Bax and E-cadherin before and after chemoembolization was insignificant. When b-value was 100 s/mm2, there was a linear correlation between PCNA expression and ADC in the area of VX-2 tumor periphery (P < 0.001), and PCNA expression in VX-2 tumor periphery influenced the ADC. CONCLUSION: The potential of VX-2 tumor infiltrating and metastasizing decreases, while its ability to proliferate increases for a short time after chemoembolization. To some degree, the ADC value indirectly reflects the proliferation of VX-2 tumor cells.展开更多
As the largest natural selenium-enriched soil area in China,Guangxi has achieved a leapfrog development in its selenium-enriched industry through the implementation of major scientific and technological projects drive...As the largest natural selenium-enriched soil area in China,Guangxi has achieved a leapfrog development in its selenium-enriched industry through the implementation of major scientific and technological projects driven by selenium-enriched innovation.The selenium-enriched industry has also become a new force in the poverty alleviation industry in Guangxi,making remarkable achievements.While summarizing and sorting out the effective measures and effects of scientific and technological innovation driving the development of selenium-enriched industry,the present paper analyzed some shortcomings and problems in the high-quality development of the selenium-enriched industry driven by the scientific and technological innovation.Finally,in view of the problems,it came up with pertinent recommendations and countermeasures,to better promote high-quality development of the selenium-enriched industry and boost the rural revitalization.展开更多
Since the China Non-Ferrous Metal Industry Corporation was founded, it has always adhered to the development principle of "Science and technology are a production force" and "Economic construction must ...Since the China Non-Ferrous Metal Industry Corporation was founded, it has always adhered to the development principle of "Science and technology are a production force" and "Economic construction must rely on science and technology progress and science and technology must serve economic construction in return" to enhance the reform in the scientific research system. With support from the State and展开更多
Purposes:This study uses the method of qualitative research to conduct in-depth interviews with pregnant women,explore the experiences of pregnant women undertake mindfulness training.Methods:The study adopts a qualit...Purposes:This study uses the method of qualitative research to conduct in-depth interviews with pregnant women,explore the experiences of pregnant women undertake mindfulness training.Methods:The study adopts a qualitative,in-depth interview method.Semi-structured interviews were conducted with 10 pregnant women.Data from semi-structured interviews were analysed by qualitative content analysis using QSR NVivo 12 software.Results:Four themes were generated to show how pregnant women experiences of the mindfulness training.They are Emotion management,Benefits of mindfulness training for childbirth,Challenges and influencing factors of mindfulness training and Different attitudes toward mindfulness training.Conclusions:Pregnant women undertaking mindfulness training can effectively reduce stress and has positive effects on work and life.Mindfulness training can be used as a way to improve the mental health of pregnant women.展开更多
AIM: To investigate dynamical and image pathological characteristics of the liver on magnetic resonance (MR) diffusion-weighted imaging (DWI) in the rabbit VX-2 tumor model. METHODS: Forty New Zealand rabbits we...AIM: To investigate dynamical and image pathological characteristics of the liver on magnetic resonance (MR) diffusion-weighted imaging (DWI) in the rabbit VX-2 tumor model. METHODS: Forty New Zealand rabbits were included in the study and VX-2 tumor piece was implanted intrahepatically. Fifteen animals received two intrahepatic implantations while 25 had one intrahepatical implantation. DWI, T1- and T2-weighted of magnetic resonance imaging (MRI) were carried out on the 7th and the 14th d after implantation and DWI was conducted, respectively on the 21th d. Ten VX-2 tumor samples were studied pathologically. RESULTS: The rate of lump detected by DWI, TlWI and T2WI was 78.7%, 10.7% and 53.5% (X^2 =32.61, P 〈 0.001) on the 7th d after implantation and 95.8%, 54.3% and 82.9% (X^2 = 21.50, P 〈 0.001) on the 14th d. The signal of most VX-2 tumors on DWI was uniform and it was equal diffusion coefficient (ADC). did not decrease on the 7th on the map of apparent The signal of VX tumors d after implantation, most of them slowly growing during the week following implantation without significant cell dying within the tumor. VX-2 tumors grew increasingly within 14 d after implantation but the signal of most VX-2 tumors on DWI or on the map of ADC was uniform or uneven and ADC of VX tumors decreased obscurely or slightly because tumor necrosis was still not obvious. On the 21th d after implantation, the signal of most VX-2 tumors on DWI or on the map of ADC was uneven because tumor necrosis was evident and ADC of VX-2 tumor necrotic areas decreased. The areas of viable cells in VX-2 tumors manifested a high signal on DWI and a low signal on the map of ADC. The areas of dead cells or necrosis in VX-2 tumors manifested low signals on DWI and low, equal or high signals on the map of ADC but they manifested high signals on DWI and on the map of ADC at the same time when the areas of necrotic tumor became liquefied or cystic. The border of tumors on DWI appeared gradually distinct and internal signals of tumor became progressively uneven. CONCLUSION: The manifestations of viable, necrotic and liquefied or cystic areas in VX-2 tumors on DWI are typical and DWI is of significant and potential values in clinical application in both the early detection and diagnosis of liver tumors.展开更多
The supported Pt catalysts(1 wt%)were prepared by the incipient impregnation method and analyzed using synchrotron-based X-ray diffraction,BET surface area,oxygen adsorption,CO pulse chemisorption,temperature-programm...The supported Pt catalysts(1 wt%)were prepared by the incipient impregnation method and analyzed using synchrotron-based X-ray diffraction,BET surface area,oxygen adsorption,CO pulse chemisorption,temperature-programmed desorption(TPD)of acetic acid,H2-TPD,NH3-TPD,O2-TPD,and H2-TPR.The reactivity of Pt-based catalysts was studied using a fixed bed reactor at 300 C and 4 MPa for hydrodeoxygenation of acetic acid,where Pt/TiO2 was very selective for ethane production.TPD experiments revealed that several conditions must be satisfied to achieve this high selectivity to ethane from acetic acid,such as Pt sites,moderate acidity,and medium metal-oxygen bond strength in the oxide support.This work provides insights in developing novel catalytic materials for hydrocarbon productions from various organics including bio-fuels.展开更多
The detailed reaction pathway and coke formation mechanism over Pt/metal oxide nanoparticles during the steam reforming of ethanol (SRE) at 300℃ were studied. The catalysts were prepared by incipient wetness impreg...The detailed reaction pathway and coke formation mechanism over Pt/metal oxide nanoparticles during the steam reforming of ethanol (SRE) at 300℃ were studied. The catalysts were prepared by incipient wetness impregnation method and were characterized with CO pulse chemisorption, BET surface measurement, oxygen adsorption, ethanol-TPD, NH3-TPD, and TPO. The SRE activity of the catalysts with steam/ethanol molar ratio of 3/1 was tested using a continuous fixed-bed reactor. Strong interaction between Pt and supports causes lower H2 production temperatures and no C2H4 formation, while weak interaction leads to C2H4 formation and strong bonded CO on Pt particles during ethanol- TPD. H2 production over Pt-based catalysts is mainly resulted from the decomposition and dehydrogenation of ethanol, and decarbonylation of acetaldehyde. Meanwhile, coke can be formed from acetaldehyde, acetone, C2H4 and CO. However, when the interaction between Pt and supports is weak, more coke is formed especially from acetone, C2H4 and CO. When the interaction is strong, no coke formation is observed due to high oxygen storage capacity of the catalyst.展开更多
Guangxi is the largest sugar producing area in China and shoulders heavy responsibilities for the development of China’s sugar industry.In recent years,China’s sugar industry has been greatly impacted by the foreign...Guangxi is the largest sugar producing area in China and shoulders heavy responsibilities for the development of China’s sugar industry.In recent years,China’s sugar industry has been greatly impacted by the foreign low-cost sugar industry,and the planting area of sugarcane has been declining.The development foundation of the sugar industry is the sugarcane seed industry.Under the impact of foreign low-price sugar,China’s sugarcane industry is under greater pressure for development,and the sugarcane seed industry shoulders more arduous responsibilities.In order to cope with international competition,the development of Guangxi’s sugarcane industry urgently needs to establish a development model oriented towards improved varieties,scale and mechanization of sugarcane,so as to promote the high-quality development of Guangxi’s sugarcane industry and effectively respond to the pressure of competition in the international sugarcane industry.展开更多
Online social networking sites ( OSNS) ,as a popular social media platform,have been developed massively for business and research purposes. In this paper,it investigated the impact of community structure in online so...Online social networking sites ( OSNS) ,as a popular social media platform,have been developed massively for business and research purposes. In this paper,it investigated the impact of community structure in online social network on information propagation. A SI (Susceptible-Infected) model based on community structure was proposed. In the SI model,the heterogeneity of user's active time was taken into account. From the results,it was found that the number of links among communities determines the fraction of infected nodes. With the increase of the number of groups G,however,the fraction of infected nodes remains approximately constant. The simulation results will be of great significance: the information will last relatively short for group networks which have either a small or a large number of groups. The results can be useful for optimizing or controlling information,such as propagating rumors in online social networks.展开更多
基金Supported by the Study on Chen Zhiqian's Public Health Thought Theory and Practice in Urban and Rural Areas(No.:3332022175).
文摘Since the early 20th century,China has gradually established a clinical,educational,and research system centered around modern scientific medicine,which has now become the dominant force in China's medical and health system and services,with the construction and development of the Chinese Academy of Medical Sciences and Peking Union Medical College as the most prominent symbol.The scientific medicine in the new era requires close cooperation across multiple disciplines and fields to build a high-quality and efficient medical and health service system.It also involves combining the excellent traditional Chinese culture with Western medicine to explore a unique path of modern scientific medicine with Chinese characteristics.
文摘Recent years have witnessed a dynamic develop of Peking Union Medical College(PUMC),which was founded in 1921,and Chinese Academy of Medical Sciences(CAMS),which was founded in 1956.In the new era of building a"Healthy China",General Secretary Xi Jinping has emphasized the importance of a profound understanding of the Chinese civilization to let the world better know and understand China,and urged efforts to combine theories and practices to expound how to better uphold the Chinese path,promote the Chinese spirit,and pool together the Chinese strength[1].As an active response,PUMC organized the first Conference of History of Medicine on May 20-21,2023[2],Based on the rich history of PUMC and with an attempt to explore history,inherit the traditional Chinese culture,and promote the spirit of modern medicine,we issued the following call at the conference。
基金the National Natural Science Foundation of China, No. 30070235, 30470508
文摘AIM: To investigate dynamic characteristics and pathological mechanism of signal in rabbit VX-2 tumor model on diffusion-weighted imaging (DWI) after chemoembolization. METHODS: Forty New Zealand rabbits were included in the study and forty-seven rabbit VX-2 tumor models were raised by implanting directly and intrahepatically after abdominal cavity opened. Forty VX-2 tumor models from them were divided into four groups. DWI was performed periodically and respectively for each group after chemoembolization. All VX-2 tumor samples of each group were studied by pathology. The distinction of VX-2 tumors on DWI was assessed by their apparent diffusion coefficient (ADC) values. The statistical significance between different time groups, different area groups or different b-value groups was calculated by using SPSS12.0 software. RESULTS: Under b-value of 100 s/mm2, ADC values were lowest at 16 h after chemoembolization in area of VX-2 tumor periphery, central, and normal liver parenchyma around tumor, but turned to increase with further elongation of chemoembolization treatment. The distinction of ADC between different time groups was significant respectively (F = 7.325, P < 0.001; F = 2.496, P < 0.048; F = 6.856, P < 0.001). Cellular edema in the area of VX-2 tumor periphery or normal liver parenchyma around tumor, increased quickly in sixteen h after chemoembolization but, from the 16th h to the 48th h, cellular edema in the area of normal liver parenchyma around tumor decreased gradually and that in the area of VX-2 tumor periphery decreased lightly at, and then increased continually. After chemoembolization, Cellular necrosis in the area of VX-2 tumor periphery was more significantly high than that before chemoembolization. The areas of dead cells in VX-2 tumors manifested low signal and high ADC value, while the areas of viable cells manifested high signal and low ADC value. CONCLUSION: DWI is able to detect and differentiate tumor necrotic areas from viable cellular areas before and after chemoembolization. ADC of normal liver parenchyma and VX-2 tumor are influenced by intracellular edema, tissue cellular death and microcirculation disturbance after chemoembolization.
基金National Key Research and Development Program of China(2017YFB0310400)National Natural Science Foundation of China(51572277,51702340)+1 种基金Shanghai Sailing Program(17YF1428800)Natural Science Foundation of Shanghai(17ZR1434800)。
文摘As for ceramic stereolithography technique,the preparation of suitable resin-based ceramic slurry is of primary importance.In this study,the effects of powder characteristics such as specific surface area,particle size and distribution,particle morphology on the rheological behavior of zirconia resin-based suspensions were investigated intensively.Results show that the specific surface area of the powder is the most important factor affecting slurry viscosity.Choosing low specific surface area and quasi-spherical shaped powder is more likely to obtain low viscosity slurries.In addition,the influence of solid loading on the flow behavior were also studied using Krieger-Dougherty model.Zirconia samples with the relative density of(97.83±0.33)%were obtained after sintering at 1550℃.No obvious abnormal grain growth in the microstructure of the sintered body is observed.Results indicate that after the optimization of the processing parameters with the help of rheology characterization,complex-shaped high-quality zirconia parts can be obtained using the stereolithography technique.
基金The National Natural Science Foundation of China, No. 30070235 and 30470508The Natural Science Foundation of Hunan Province, No. 08JJ5043+1 种基金The Science and Technology Foundation of Hunan Province, No. 06FJ3120 and 2007SK3072The Medical Science and Technology Foundation of Hunan Province, No. B2006-159
文摘AIM: To investigate the dynamic characteristics and the correlation between PCNA, Bax, nm23, E-cadherin expression and apparent diffusion coefficient (ADC) on MR diffusion-weighted imaging (DWI) after chemoembolization in rabbit liver VX-2 tumor model. METHODS: Forty New Zealand rabbit liver VX-2 tumor models were included in the study. DWI was carried out periodically after chemoembolization. All VX-2 tumor samples in each group were examined by histopathology and Strept Avidin-Biotin Complex (SABC) immunohistochemical staining. RESULTS: The PCNA expression index in VX-2 tumors was higher than in the normal parenchyma around the tumor (P < 0.001). Nm23, Bax or E-caderin expression index in VX-2 tumors were lower than in the normal parenchyma around the tumor (all P < 0.001). PCNAand nm23 expression in the VX-2 tumor periphery first increased and then decreased (P < 0.001 and P = 0.03, respectively), while the expression of Bax and E-cadherin before and after chemoembolization was insignificant. When b-value was 100 s/mm2, there was a linear correlation between PCNA expression and ADC in the area of VX-2 tumor periphery (P < 0.001), and PCNA expression in VX-2 tumor periphery influenced the ADC. CONCLUSION: The potential of VX-2 tumor infiltrating and metastasizing decreases, while its ability to proliferate increases for a short time after chemoembolization. To some degree, the ADC value indirectly reflects the proliferation of VX-2 tumor cells.
基金Supported by Key Science and Technology Project of Guangxi(Gui Ke AA17202026)“Six Great Projects”Special Action of Science and Technology Pioneer for“Strengthening Farmers and Enriching the People”(Gui Nong Ke Meng 202014)+1 种基金Science and Technology Pioneer Special Action of Guangxi Academy of Agricultural Sciences(Gui Nong Ke JZ202016)Selenium-enriched Specialty Crop Experimental Station of Guangxi(Gui TS2016011).
文摘As the largest natural selenium-enriched soil area in China,Guangxi has achieved a leapfrog development in its selenium-enriched industry through the implementation of major scientific and technological projects driven by selenium-enriched innovation.The selenium-enriched industry has also become a new force in the poverty alleviation industry in Guangxi,making remarkable achievements.While summarizing and sorting out the effective measures and effects of scientific and technological innovation driving the development of selenium-enriched industry,the present paper analyzed some shortcomings and problems in the high-quality development of the selenium-enriched industry driven by the scientific and technological innovation.Finally,in view of the problems,it came up with pertinent recommendations and countermeasures,to better promote high-quality development of the selenium-enriched industry and boost the rural revitalization.
文摘Since the China Non-Ferrous Metal Industry Corporation was founded, it has always adhered to the development principle of "Science and technology are a production force" and "Economic construction must rely on science and technology progress and science and technology must serve economic construction in return" to enhance the reform in the scientific research system. With support from the State and
基金This work is supported by CAMS Innovation Fund for Medical Sciences(CIFMS)(2021-I2M-1-023).
文摘Purposes:This study uses the method of qualitative research to conduct in-depth interviews with pregnant women,explore the experiences of pregnant women undertake mindfulness training.Methods:The study adopts a qualitative,in-depth interview method.Semi-structured interviews were conducted with 10 pregnant women.Data from semi-structured interviews were analysed by qualitative content analysis using QSR NVivo 12 software.Results:Four themes were generated to show how pregnant women experiences of the mindfulness training.They are Emotion management,Benefits of mindfulness training for childbirth,Challenges and influencing factors of mindfulness training and Different attitudes toward mindfulness training.Conclusions:Pregnant women undertaking mindfulness training can effectively reduce stress and has positive effects on work and life.Mindfulness training can be used as a way to improve the mental health of pregnant women.
基金The National Natural Science Foundation of China, No. 30070235, 30470508The Natural Science Foundation of Hunan Province, No. 08JJ5043+1 种基金The Science and Technolgy Foundation of Hunan Province, No. 06FJ3120, 2007SK3072the Medical Science and Technology Foundation of Hunan Province, No. B2006-159
文摘AIM: To investigate dynamical and image pathological characteristics of the liver on magnetic resonance (MR) diffusion-weighted imaging (DWI) in the rabbit VX-2 tumor model. METHODS: Forty New Zealand rabbits were included in the study and VX-2 tumor piece was implanted intrahepatically. Fifteen animals received two intrahepatic implantations while 25 had one intrahepatical implantation. DWI, T1- and T2-weighted of magnetic resonance imaging (MRI) were carried out on the 7th and the 14th d after implantation and DWI was conducted, respectively on the 21th d. Ten VX-2 tumor samples were studied pathologically. RESULTS: The rate of lump detected by DWI, TlWI and T2WI was 78.7%, 10.7% and 53.5% (X^2 =32.61, P 〈 0.001) on the 7th d after implantation and 95.8%, 54.3% and 82.9% (X^2 = 21.50, P 〈 0.001) on the 14th d. The signal of most VX-2 tumors on DWI was uniform and it was equal diffusion coefficient (ADC). did not decrease on the 7th on the map of apparent The signal of VX tumors d after implantation, most of them slowly growing during the week following implantation without significant cell dying within the tumor. VX-2 tumors grew increasingly within 14 d after implantation but the signal of most VX-2 tumors on DWI or on the map of ADC was uniform or uneven and ADC of VX tumors decreased obscurely or slightly because tumor necrosis was still not obvious. On the 21th d after implantation, the signal of most VX-2 tumors on DWI or on the map of ADC was uneven because tumor necrosis was evident and ADC of VX-2 tumor necrotic areas decreased. The areas of viable cells in VX-2 tumors manifested a high signal on DWI and a low signal on the map of ADC. The areas of dead cells or necrosis in VX-2 tumors manifested low signals on DWI and low, equal or high signals on the map of ADC but they manifested high signals on DWI and on the map of ADC at the same time when the areas of necrotic tumor became liquefied or cystic. The border of tumors on DWI appeared gradually distinct and internal signals of tumor became progressively uneven. CONCLUSION: The manifestations of viable, necrotic and liquefied or cystic areas in VX-2 tumors on DWI are typical and DWI is of significant and potential values in clinical application in both the early detection and diagnosis of liver tumors.
文摘The supported Pt catalysts(1 wt%)were prepared by the incipient impregnation method and analyzed using synchrotron-based X-ray diffraction,BET surface area,oxygen adsorption,CO pulse chemisorption,temperature-programmed desorption(TPD)of acetic acid,H2-TPD,NH3-TPD,O2-TPD,and H2-TPR.The reactivity of Pt-based catalysts was studied using a fixed bed reactor at 300 C and 4 MPa for hydrodeoxygenation of acetic acid,where Pt/TiO2 was very selective for ethane production.TPD experiments revealed that several conditions must be satisfied to achieve this high selectivity to ethane from acetic acid,such as Pt sites,moderate acidity,and medium metal-oxygen bond strength in the oxide support.This work provides insights in developing novel catalytic materials for hydrocarbon productions from various organics including bio-fuels.
文摘The detailed reaction pathway and coke formation mechanism over Pt/metal oxide nanoparticles during the steam reforming of ethanol (SRE) at 300℃ were studied. The catalysts were prepared by incipient wetness impregnation method and were characterized with CO pulse chemisorption, BET surface measurement, oxygen adsorption, ethanol-TPD, NH3-TPD, and TPO. The SRE activity of the catalysts with steam/ethanol molar ratio of 3/1 was tested using a continuous fixed-bed reactor. Strong interaction between Pt and supports causes lower H2 production temperatures and no C2H4 formation, while weak interaction leads to C2H4 formation and strong bonded CO on Pt particles during ethanol- TPD. H2 production over Pt-based catalysts is mainly resulted from the decomposition and dehydrogenation of ethanol, and decarbonylation of acetaldehyde. Meanwhile, coke can be formed from acetaldehyde, acetone, C2H4 and CO. However, when the interaction between Pt and supports is weak, more coke is formed especially from acetone, C2H4 and CO. When the interaction is strong, no coke formation is observed due to high oxygen storage capacity of the catalyst.
基金Supported by Special Project for Chairman Academician Advisor of Guangxi Zhuang Autonomous Region(ZH040040)Special Project for Central Leading Local Science and Technology Development(Gui Ke ZY19183007)
文摘Guangxi is the largest sugar producing area in China and shoulders heavy responsibilities for the development of China’s sugar industry.In recent years,China’s sugar industry has been greatly impacted by the foreign low-cost sugar industry,and the planting area of sugarcane has been declining.The development foundation of the sugar industry is the sugarcane seed industry.Under the impact of foreign low-price sugar,China’s sugarcane industry is under greater pressure for development,and the sugarcane seed industry shoulders more arduous responsibilities.In order to cope with international competition,the development of Guangxi’s sugarcane industry urgently needs to establish a development model oriented towards improved varieties,scale and mechanization of sugarcane,so as to promote the high-quality development of Guangxi’s sugarcane industry and effectively respond to the pressure of competition in the international sugarcane industry.
基金Sponsored by the National Basic Research Program of China (973 Program) (Grant No. 2012CB315805)National Natural Science Foundation ofChina (Grant No. 71172135)
文摘Online social networking sites ( OSNS) ,as a popular social media platform,have been developed massively for business and research purposes. In this paper,it investigated the impact of community structure in online social network on information propagation. A SI (Susceptible-Infected) model based on community structure was proposed. In the SI model,the heterogeneity of user's active time was taken into account. From the results,it was found that the number of links among communities determines the fraction of infected nodes. With the increase of the number of groups G,however,the fraction of infected nodes remains approximately constant. The simulation results will be of great significance: the information will last relatively short for group networks which have either a small or a large number of groups. The results can be useful for optimizing or controlling information,such as propagating rumors in online social networks.