As two major Great Powers in the geopolitics of the Balkans,the relationship between Austria-Hungary and Russia directly affected the stability of the political situation in Europe and the Balkans.At the beginning of ...As two major Great Powers in the geopolitics of the Balkans,the relationship between Austria-Hungary and Russia directly affected the stability of the political situation in Europe and the Balkans.At the beginning of the 20th century,the Austro-Russian cooperation dominated the Macedonian reforms,but with the deepening of the reforms,the structural contradictions between the two countries were fully exposed,and the original cooperative relationship went to a rupture.This drastically changed relationship became an important factor in the restructuring of relations between the Great Powers and the Balkan states before the First World War.展开更多
Society is currently transitioning from the era of informatization and digitization to the era of intelligence.Advanced technologies such as artificial intelligence,the Internet of Things,and big data are permeating e...Society is currently transitioning from the era of informatization and digitization to the era of intelligence.Advanced technologies such as artificial intelligence,the Internet of Things,and big data are permeating every aspect of production and life.This penetration presents a rare opportunity for the development of digital trade and catalyzes innovation in traditional trade patterns.This paper first analyzes the inevitability of digital trade development in Northeast Asia.Secondly,it delves into the challenges faced by digital trade development and explores in-depth the promotion strategy for digital trade’s impact on the economic development of the Northeast Asia region,providing insights from various perspectives for reference.展开更多
Owing to the continuous advancement of information technology,smart education has become a new direction for educational development.Through investigation,it was found that there is an imbalanced education development...Owing to the continuous advancement of information technology,smart education has become a new direction for educational development.Through investigation,it was found that there is an imbalanced education development in some regions.To promote the integration of urban and rural education,promoting regional smart education as a whole will be the key to solving this problem.Based on this direction,this study focused on explaining the concept and characteristics of smart education,the value and significance of regional smart education,the problems and challenges of regional smart education,and strategies and measures to promote the development of regional smart education.This is significant to form a universal regional smart education promotion strategy and provide reference for the overall promotion of smart education.展开更多
The inherent teaching approach can no longer meet the demands of society.In this paper,current issues within the teaching landscape of architectural engineering technology in higher vocational colleges as well as the ...The inherent teaching approach can no longer meet the demands of society.In this paper,current issues within the teaching landscape of architectural engineering technology in higher vocational colleges as well as the policies and teaching demands that formed the basis of this model were analyzed.The study shows the importance of the implementation of the teaching model“promoting teaching and learning through competitions.”This model puts emphasis on the curriculum and teaching resources,while also integrating the teaching process and evaluation with competition.These efforts aim to drive education reform in order to better align with the objectives of vocational education personnel training,while also acting as a reference for similar courses.展开更多
Combining with the characteristics of the“Foreign Trade Correspondence”course of Business English major of Quzhou University,in order to make a breakthrough in the teaching goal,the article proposes that the“Foreig...Combining with the characteristics of the“Foreign Trade Correspondence”course of Business English major of Quzhou University,in order to make a breakthrough in the teaching goal,the article proposes that the“Foreign Trade Correspondence”course teaching should be integrated with local characteristics and form a benign interaction with the local economic development。展开更多
Economic growth and environmental "friendliness" are the dual missions of China's grand western development. In the past eight years,China has seen the gap between eastern and western regions still widen...Economic growth and environmental "friendliness" are the dual missions of China's grand western development. In the past eight years,China has seen the gap between eastern and western regions still widening while also taking on the arduous task of protecting nature,ecology and environment in the western region. How has western development fared in the past eight years? What difficulties and challenges are being encountered? The development of the western region poses the single greatest difficulty facing China's regional economic development,but how can we advance along a "sound and fast" development path? The establishment of economic zones in Chengdu and Chongqing,Guanzhong and North Bay has opened up new possibilities and expectations for western China's economic development.展开更多
A Chinese delegation of 24 persons headed by Mr. Luan Enjie, Vice Administrator of China National Space Administration (CNSA) attended the Second Asia-Pacific Conference on Multilateral Cooperation in Space Technology...A Chinese delegation of 24 persons headed by Mr. Luan Enjie, Vice Administrator of China National Space Administration (CNSA) attended the Second Asia-Pacific Conference on Multilateral Cooperation in Space Technology and Applications held at Islamabad, the Capital of Pakistan from April 22 to 26, 1995. Following the First AsiaPacific Workshop held in Beijing in December, 1992, and the First Asia-Pacific Conference on Multilateral Cooperation in展开更多
AIM: To investigate the frequency of mutations in pre-core (pre-C) and basic core promoter (BCP) regions of hepatitis B virus (HBV) from Shanxi Province, and the association between mutations and disease related index...AIM: To investigate the frequency of mutations in pre-core (pre-C) and basic core promoter (BCP) regions of hepatitis B virus (HBV) from Shanxi Province, and the association between mutations and disease related indexes.METHODS: One hundred chronic hepatitis B patients treated at Shanxi Province Hospital of Traditional Chinese Medicine were included in this study. PCR-reverse dot blot hybridization and mismatch amplification mutation assay (MAMA)-PCR were used to detect the mutations in the HBV pre-C and BCP regions. HBV DNA content and liver function were compared between patients with mutant HBV pre-C and BCP loci and those with wild-type loci. The consistency between PCR-reverse dot blot hybridization and MAMA-PCR for detecting mutations in the HBV pre-C and BCP regions was assessed.RESULTS: Of the 100 serum samples detected, 9.38% had single mutations in the pre-C region, 29.17% had single mutations in the BCP region, 41.67% had mutations in both BCP and pre-C regions, and 19.79% had wild-type loci. The rates of BCP and pre-C mutations were 65.7% and 34.3%, respectively, in hepatitis B e antigen (HBeAg) positive patients, and 84.6% and 96.2%, respectively, in HBeAg negative patients. The rate of pre-C mutations was significantly higher in HBeAg negative patients than in HBeAg positive patients (χ<sup>2</sup> = 26.62, P = 0.00), but there was no significant difference in the distribution of mutations in the BCP region between HBeAg positive and negative patients (χ<sup>2</sup> = 2.43, P = 0.12). The presence of mutations in the pre-C (Wilcoxon W = 1802.5, P = 0.00) and BCP regions (Wilcoxon W = 2906.5, P = 0.00) was more common in patients with low HBV DNA content. Both AST and GGT were significantly higher in patients with mutant pre-C and BCP loci than in those with wild-type loci (P < 0.05). PCR-reverse dot blot hybridization and MAMA-PCR for detection of mutations in the BCP and pre-C regions had good consistency, and the Kappa values obtained were 0.91 and 0.58, respectively.CONCLUSION: HBeAg negative patients tend to have HBV pre-C mutations. However, these mutations do not cause increased DNA copies, but associate with damage of liver function.展开更多
A series of Ni/SBA-15 catalysts with Ni contents ranging from 5 wt% to 15 wt%, as well as another series of 10%Ni/MgO/SBA-15 catalysts, in which the range of the MgO content was from 1 wt% to 7 wt%, were prepared, and...A series of Ni/SBA-15 catalysts with Ni contents ranging from 5 wt% to 15 wt%, as well as another series of 10%Ni/MgO/SBA-15 catalysts, in which the range of the MgO content was from 1 wt% to 7 wt%, were prepared, and their catalytic performances for the reaction of combined steam and carbon dioxide reforming of methane were investigated in a continuous flow microreactor. The structures of the catalysts were characterized using the XRD, H2-TPR and CO2-TPD techniques. The results indicated that the CO selectivity for this reaction was very close to 100%, and the H2/CO ratio of the product gas could be controlled by changing the H2O/CO2 molar ratio of the feed gas. The simultaneous and plentiful existing of steam and CO2 had a significant influence on the catalytic performance of the 10%Ni/SBA-15 catalyst without modification. After reacting at 850 °C for 120 h over this catalyst, the CH4 conversion dropped from 98% to 85%, and the CO2 conversion decreased from 86% to 53%. However, the 10%Ni/3%MgO/SBA-15 catalyst exhibited a much better catalytic performance, and after reacting for 620 h, the CO2 conversion over this catalyst dropped from 92% to around 77%, while the CH4 conversion was not decreased. Oxidation of the Ni0 species as well as carbon deposition during the reaction were the main reasons for the deactivation of the catalyst without modification. On the other hand, modification by the MgO promoter improved the dispersion of the Ni0 species, and enhanced the CO2 adsorption affinity which in turn depressed the occurring of carbon deposition, and thus retarded the deactivation process.展开更多
As a cleaner,high-efficiency,and low-carbon fuel,natural gas has been an important fuel resource for China.To achieve a substantial increase in natural gas demand,China has sought to reform its natural gas pricing mec...As a cleaner,high-efficiency,and low-carbon fuel,natural gas has been an important fuel resource for China.To achieve a substantial increase in natural gas demand,China has sought to reform its natural gas pricing mechanism.Employing a set of unbalanced panel data for China’s 30 provinces covering 1999-2015,this study aims to estimate the evolving price and income elasticities of natural gas demand and explore the effect of natural gas price reform in China.For this purpose,a series of econometric techniques allowing for cross-sectional dependence and slope homogeneity is utilized.The results suggest that although natural gas demand in China still lacks negative price elasticity,the phenomenon is improving.Moreover,the estimates suggest that natural gas demand in China is indeed becoming increasingly sensitive to income changes.Our estimates also provide strong evidence in favor of the effect of natural gas price reform on the change in price elasticity as the price elasticity decreases in five of the seven regions.In addition,the results indicate large variations in the change in price and income elasticities of natural gas demand across China’s regions.Natural gas demand is becoming more price inelastic in Southwest China and Northwest China,while such demand in North China and East China responds less sensitively to income changes.These findings offer several policy suggestions for the reform of China’s natural gas market at the national and regional levels.展开更多
The CO2reforming of CH4is studied over MgO‐promoted Ni catalysts,which were supported on alumina prepared from hydrotalcite.This presents an improved stability compared with non‐promoted catalysts.The introduction o...The CO2reforming of CH4is studied over MgO‐promoted Ni catalysts,which were supported on alumina prepared from hydrotalcite.This presents an improved stability compared with non‐promoted catalysts.The introduction of the MgO promoter was achieved through the‘‘memory effect’’of the Ni‐Al hydrotalcite structure,and ICP‐MS confirmed that only0.42wt.%of Mg2+ions were added into the Ni‐Mg/Al catalyst.Although no differences in the Ni particle size and basicity strength were observed,the Ni‐Mg/Al catalyst showed a higher catalytic stability than the Ni/Al catalyst.A series of surface reaction experiments were used and showed that the addition of a MgO promoter with low concentration can promote CO2dissociation to form active surface oxygen arising from the formation of the Ni‐MgO interface sites.Therefore,the carbon‐resistance promotion by nature was suggested to contribute to an oxidative environment around Ni particles,which would increase the conversion of carbon residues from CH4cracking to yield CO on the Ni metal surface.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved.展开更多
Objective: To analyze the genomic structure of SNC6, a progesterone\|receptor associated protein gene and its regulatory elements in its 5'\|flanking region. Methods: Genomic sequence from GenBank database (access...Objective: To analyze the genomic structure of SNC6, a progesterone\|receptor associated protein gene and its regulatory elements in its 5'\|flanking region. Methods: Genomic sequence from GenBank database (accession number: Z98048) covering the whole SNC6 gene was used to analyze the genomic structure of SNC6 and design primers for PCR amplification of its 5'\|flanking region. A 1894 bp fragment of the 5'\|flanking region \{(-1814\} to +75) was cloned by PCR using genomic DNA from a healthy donor peripheral blood lymphocyte as template. This fragment, as well as 3 shorter derivative fragments (1423 bp, 632 bp and 416 bp, which correspond to -1344 to +75, -552 to +75 and -337 to +75 respectively), were subcloned into pGL2 series luciferase reporter vectors. These constructs were introduced into colorectal cancer cell line SW620 for transient expression of reporter gene and luciferase activities were measured. Results: The genomic structure analysis showed there are 12 exons for SNC6 gene, which spans 32017 bp (nt71529 to nt39513 in Z98048 sequence). All transfected SW620 cells with the above 5\|flanking region\|containing constructs showed luciferase activities. The highest luciferase activities were measured in transfected cells with vectors containing 1894 bp fragments, and the lowest luciferase activities were measured in transfected cells with vectors containing 416 bp fragments. Luciferase activities were higher in transfected cells with vectors containing 632 bp fragments than that in transfected cells with vectors containing 1423 bp fragments. Conclusion: The basic transcription\|promoting element (promoter) for SNC6 expression resides between 0 to -337, and two transcription\|enhancing elements (enhancer) resides between -337 to -552 and -1344 to -1814, whereas one transcription\|inhibiting element (silencer) exists between -552 to -1344.展开更多
AIM: To test the hypothesis to block VEGF expression of SMMC-7721 hepatoma cells may inhibit tumor growth using the rat hepatoma model. METHODS: Amplify the 200 VEGF cDNA fragment and insert it into human U6 gene cass...AIM: To test the hypothesis to block VEGF expression of SMMC-7721 hepatoma cells may inhibit tumor growth using the rat hepatoma model. METHODS: Amplify the 200 VEGF cDNA fragment and insert it into human U6 gene cassette in the reverse orientation transcribing small antisense RNA which could specifically interact with VEGF165, and VEGF121 mRNA. Construct the retroviral vector containing this antisense VEGF U6 cassette and package the replication-deficient recombinant retrovirus. SMMC-7721 cells were transduced with these virus and positive clones were selected with G418. PCR and Southern blot analysis were performed to determine if U6 cassette integrated into the genomic DNA of positive clone. Transfected tumor cells were evaluated for RNA expression by ribonuclease protection assays. The VEGF protein in the supernatant of parental tumor cells and genetically modified tumor cells was determined with ELISA. In vitro and in vivo growth properties of antisense VEGF cell clone in nude mice were analyzed. RESULTS: Restriction enzyme digestion and PCR sequencing verified that the antisense VEGF RNA retroviral vector was successfully constructed.After G418 selection, resistant SMMC-7721 cell clone was picked up. PCR and Southern blot analysis suggested that U6 cassette was integrated into the cell genomic DNA. Stable SMMC-7721 cell clone transduced with U6 antisense RNA cassette could express 200 bp small antisense VEGF RNA and secrete reduced levels of VEGF in culture condition. Production of VEGF by antisense transgene-expressing cells was 65+/-10 ng/L per 10(6) cells, 42045 ng/L per 10(6) cells in sense group and 485+/-30 ng/L per 10(6) cells in the negative control group, (P【 0.05). The antisense-VEGF cell clone appeared phenotypically indistinguishable from SMMC-7721 cells and SMMC-7721 cells transfected sense VEGF. The growth rate of the antisense-VEGF cell clone was the same as the control cells. When S.C. was implanted into nude mice, growth of antisense-VEGF cell lines was greatly inhibited compared with control cells. CONCLUSION: Expression of antisense VEGF RNA in SMMC-7721 cells could decrease the tumorigenicity, and antisense-VEGF gene therapy may be an adjuvant treatment for hepatoma.展开更多
In the current study simultaneous reactions of hydrodesulfurization(HDS) of dibenzothiophene(DBT) and reforming of methanol in a micro-autoclave reactor were studied over bi-metallic(Co-Mo/Al2O3 and Ni-Mo/Al2O3) and t...In the current study simultaneous reactions of hydrodesulfurization(HDS) of dibenzothiophene(DBT) and reforming of methanol in a micro-autoclave reactor were studied over bi-metallic(Co-Mo/Al2O3 and Ni-Mo/Al2O3) and tri-metallic(Pd-Co-Mo/Al2O3 and Pd-Ni-Mo/Al2O3) catalyst systems which were prepared by incipient impregnation method.In situ hydrogen utilization and low Pd loadings were the major targets of this study.For comparison purpose,catalytic activity was separately determined for both the methanol reforming and HDS of DBT reactions as well.Ni based catalysts were confirmed with better activity than Co ones for both the reactions with Pd promoted ones ranking at the top i.e.Pd-Ni-Mo/Al2O3 > Ni-Mo/Al2O3 > Pd-Co-Mo/Al2O3 > Co-Mo/Al2O3 where Pd-Ni-Mo/Al2O3 showed 91% DBT conversion at 380 ℃ and 12 h reaction time.Some of the selected organic additives on catalytic activity were tested for their effect toward HDS reaction which was unique with close relation to their chemical nature.Reaction products were quantitatively and qualitatively analyzed via HPLC and GC-MS techniques respectively which helped in elucidating reaction mechanism.展开更多
There are a number of factors involved in teaching quality. Among them teaching materials or textbooks are of primary importance, the presentation of which relies first of all on the viewpoint to structure the content...There are a number of factors involved in teaching quality. Among them teaching materials or textbooks are of primary importance, the presentation of which relies first of all on the viewpoint to structure the contents geographically. Whatever branch of geography you are teaching or in pursuit, geographical viewpoint is vitally important. This paper in discussing innovation of geographical education about these institutions with the course of regional physical geography as an example. The higher education of our discipline is in pressing need of innovation and thereby upgrading quality.展开更多
Evidence supports the involvement of oxytocin in social behavior. The oxytocin receptor gene (OXTR) has been associated with differences in social brain function and risk for autism. Motivated by recent work, we inves...Evidence supports the involvement of oxytocin in social behavior. The oxytocin receptor gene (OXTR) has been associated with differences in social brain function and risk for autism. Motivated by recent work, we investigated the effect of variation in the common functional rs2268498 T/C polymorphism in the promoter region of OXTR on neural responses to fear expressions. 46 healthy subjects were divided into genotype groups of C carriers (n = 32) and TT ho-mozygous (n = 14) and neural activity was measured during the recognition of fear and neutral expressions. Results showed that during the recognition of fear expressions, the TT genotype group exhibited increased responding in the inferior occipital gyrus, considered important for face processing, compared to carriers of the C allele (P < 0.005;cluster corrected for whole brain), an effect not found for neutral faces. These results indicate the impact of this OXTR genetic variant on individual differences in social affective neural processing.展开更多
文摘As two major Great Powers in the geopolitics of the Balkans,the relationship between Austria-Hungary and Russia directly affected the stability of the political situation in Europe and the Balkans.At the beginning of the 20th century,the Austro-Russian cooperation dominated the Macedonian reforms,but with the deepening of the reforms,the structural contradictions between the two countries were fully exposed,and the original cooperative relationship went to a rupture.This drastically changed relationship became an important factor in the restructuring of relations between the Great Powers and the Balkan states before the First World War.
文摘Society is currently transitioning from the era of informatization and digitization to the era of intelligence.Advanced technologies such as artificial intelligence,the Internet of Things,and big data are permeating every aspect of production and life.This penetration presents a rare opportunity for the development of digital trade and catalyzes innovation in traditional trade patterns.This paper first analyzes the inevitability of digital trade development in Northeast Asia.Secondly,it delves into the challenges faced by digital trade development and explores in-depth the promotion strategy for digital trade’s impact on the economic development of the Northeast Asia region,providing insights from various perspectives for reference.
文摘Owing to the continuous advancement of information technology,smart education has become a new direction for educational development.Through investigation,it was found that there is an imbalanced education development in some regions.To promote the integration of urban and rural education,promoting regional smart education as a whole will be the key to solving this problem.Based on this direction,this study focused on explaining the concept and characteristics of smart education,the value and significance of regional smart education,the problems and challenges of regional smart education,and strategies and measures to promote the development of regional smart education.This is significant to form a universal regional smart education promotion strategy and provide reference for the overall promotion of smart education.
文摘The inherent teaching approach can no longer meet the demands of society.In this paper,current issues within the teaching landscape of architectural engineering technology in higher vocational colleges as well as the policies and teaching demands that formed the basis of this model were analyzed.The study shows the importance of the implementation of the teaching model“promoting teaching and learning through competitions.”This model puts emphasis on the curriculum and teaching resources,while also integrating the teaching process and evaluation with competition.These efforts aim to drive education reform in order to better align with the objectives of vocational education personnel training,while also acting as a reference for similar courses.
文摘Combining with the characteristics of the“Foreign Trade Correspondence”course of Business English major of Quzhou University,in order to make a breakthrough in the teaching goal,the article proposes that the“Foreign Trade Correspondence”course teaching should be integrated with local characteristics and form a benign interaction with the local economic development。
文摘Economic growth and environmental "friendliness" are the dual missions of China's grand western development. In the past eight years,China has seen the gap between eastern and western regions still widening while also taking on the arduous task of protecting nature,ecology and environment in the western region. How has western development fared in the past eight years? What difficulties and challenges are being encountered? The development of the western region poses the single greatest difficulty facing China's regional economic development,but how can we advance along a "sound and fast" development path? The establishment of economic zones in Chengdu and Chongqing,Guanzhong and North Bay has opened up new possibilities and expectations for western China's economic development.
文摘A Chinese delegation of 24 persons headed by Mr. Luan Enjie, Vice Administrator of China National Space Administration (CNSA) attended the Second Asia-Pacific Conference on Multilateral Cooperation in Space Technology and Applications held at Islamabad, the Capital of Pakistan from April 22 to 26, 1995. Following the First AsiaPacific Workshop held in Beijing in December, 1992, and the First Asia-Pacific Conference on Multilateral Cooperation in
基金Supported by Youth Foundation of Health and Family Planning Commission of Shanxi ProvinceNo.201301024
文摘AIM: To investigate the frequency of mutations in pre-core (pre-C) and basic core promoter (BCP) regions of hepatitis B virus (HBV) from Shanxi Province, and the association between mutations and disease related indexes.METHODS: One hundred chronic hepatitis B patients treated at Shanxi Province Hospital of Traditional Chinese Medicine were included in this study. PCR-reverse dot blot hybridization and mismatch amplification mutation assay (MAMA)-PCR were used to detect the mutations in the HBV pre-C and BCP regions. HBV DNA content and liver function were compared between patients with mutant HBV pre-C and BCP loci and those with wild-type loci. The consistency between PCR-reverse dot blot hybridization and MAMA-PCR for detecting mutations in the HBV pre-C and BCP regions was assessed.RESULTS: Of the 100 serum samples detected, 9.38% had single mutations in the pre-C region, 29.17% had single mutations in the BCP region, 41.67% had mutations in both BCP and pre-C regions, and 19.79% had wild-type loci. The rates of BCP and pre-C mutations were 65.7% and 34.3%, respectively, in hepatitis B e antigen (HBeAg) positive patients, and 84.6% and 96.2%, respectively, in HBeAg negative patients. The rate of pre-C mutations was significantly higher in HBeAg negative patients than in HBeAg positive patients (χ<sup>2</sup> = 26.62, P = 0.00), but there was no significant difference in the distribution of mutations in the BCP region between HBeAg positive and negative patients (χ<sup>2</sup> = 2.43, P = 0.12). The presence of mutations in the pre-C (Wilcoxon W = 1802.5, P = 0.00) and BCP regions (Wilcoxon W = 2906.5, P = 0.00) was more common in patients with low HBV DNA content. Both AST and GGT were significantly higher in patients with mutant pre-C and BCP loci than in those with wild-type loci (P < 0.05). PCR-reverse dot blot hybridization and MAMA-PCR for detection of mutations in the BCP and pre-C regions had good consistency, and the Kappa values obtained were 0.91 and 0.58, respectively.CONCLUSION: HBeAg negative patients tend to have HBV pre-C mutations. However, these mutations do not cause increased DNA copies, but associate with damage of liver function.
基金the National Basic Research Program ofChina (Project No. 2005CB221405)the National "863" Project ofChina (No. 2006AA10Z425)the Beijing Natural Science Foun-dation (Project No: 8062023)
文摘A series of Ni/SBA-15 catalysts with Ni contents ranging from 5 wt% to 15 wt%, as well as another series of 10%Ni/MgO/SBA-15 catalysts, in which the range of the MgO content was from 1 wt% to 7 wt%, were prepared, and their catalytic performances for the reaction of combined steam and carbon dioxide reforming of methane were investigated in a continuous flow microreactor. The structures of the catalysts were characterized using the XRD, H2-TPR and CO2-TPD techniques. The results indicated that the CO selectivity for this reaction was very close to 100%, and the H2/CO ratio of the product gas could be controlled by changing the H2O/CO2 molar ratio of the feed gas. The simultaneous and plentiful existing of steam and CO2 had a significant influence on the catalytic performance of the 10%Ni/SBA-15 catalyst without modification. After reacting at 850 °C for 120 h over this catalyst, the CH4 conversion dropped from 98% to 85%, and the CO2 conversion decreased from 86% to 53%. However, the 10%Ni/3%MgO/SBA-15 catalyst exhibited a much better catalytic performance, and after reacting for 620 h, the CO2 conversion over this catalyst dropped from 92% to around 77%, while the CH4 conversion was not decreased. Oxidation of the Ni0 species as well as carbon deposition during the reaction were the main reasons for the deactivation of the catalyst without modification. On the other hand, modification by the MgO promoter improved the dispersion of the Ni0 species, and enhanced the CO2 adsorption affinity which in turn depressed the occurring of carbon deposition, and thus retarded the deactivation process.
基金Financial support from the National Social Science Foundation of China (Grant Nos.17BGL014 and 18VDL017)
文摘As a cleaner,high-efficiency,and low-carbon fuel,natural gas has been an important fuel resource for China.To achieve a substantial increase in natural gas demand,China has sought to reform its natural gas pricing mechanism.Employing a set of unbalanced panel data for China’s 30 provinces covering 1999-2015,this study aims to estimate the evolving price and income elasticities of natural gas demand and explore the effect of natural gas price reform in China.For this purpose,a series of econometric techniques allowing for cross-sectional dependence and slope homogeneity is utilized.The results suggest that although natural gas demand in China still lacks negative price elasticity,the phenomenon is improving.Moreover,the estimates suggest that natural gas demand in China is indeed becoming increasingly sensitive to income changes.Our estimates also provide strong evidence in favor of the effect of natural gas price reform on the change in price elasticity as the price elasticity decreases in five of the seven regions.In addition,the results indicate large variations in the change in price and income elasticities of natural gas demand across China’s regions.Natural gas demand is becoming more price inelastic in Southwest China and Northwest China,while such demand in North China and East China responds less sensitively to income changes.These findings offer several policy suggestions for the reform of China’s natural gas market at the national and regional levels.
基金supported by the National Natural Science Fundation of China(U1361202,51276120)~~
文摘The CO2reforming of CH4is studied over MgO‐promoted Ni catalysts,which were supported on alumina prepared from hydrotalcite.This presents an improved stability compared with non‐promoted catalysts.The introduction of the MgO promoter was achieved through the‘‘memory effect’’of the Ni‐Al hydrotalcite structure,and ICP‐MS confirmed that only0.42wt.%of Mg2+ions were added into the Ni‐Mg/Al catalyst.Although no differences in the Ni particle size and basicity strength were observed,the Ni‐Mg/Al catalyst showed a higher catalytic stability than the Ni/Al catalyst.A series of surface reaction experiments were used and showed that the addition of a MgO promoter with low concentration can promote CO2dissociation to form active surface oxygen arising from the formation of the Ni‐MgO interface sites.Therefore,the carbon‐resistance promotion by nature was suggested to contribute to an oxidative environment around Ni particles,which would increase the conversion of carbon residues from CH4cracking to yield CO on the Ni metal surface.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved.
文摘Objective: To analyze the genomic structure of SNC6, a progesterone\|receptor associated protein gene and its regulatory elements in its 5'\|flanking region. Methods: Genomic sequence from GenBank database (accession number: Z98048) covering the whole SNC6 gene was used to analyze the genomic structure of SNC6 and design primers for PCR amplification of its 5'\|flanking region. A 1894 bp fragment of the 5'\|flanking region \{(-1814\} to +75) was cloned by PCR using genomic DNA from a healthy donor peripheral blood lymphocyte as template. This fragment, as well as 3 shorter derivative fragments (1423 bp, 632 bp and 416 bp, which correspond to -1344 to +75, -552 to +75 and -337 to +75 respectively), were subcloned into pGL2 series luciferase reporter vectors. These constructs were introduced into colorectal cancer cell line SW620 for transient expression of reporter gene and luciferase activities were measured. Results: The genomic structure analysis showed there are 12 exons for SNC6 gene, which spans 32017 bp (nt71529 to nt39513 in Z98048 sequence). All transfected SW620 cells with the above 5\|flanking region\|containing constructs showed luciferase activities. The highest luciferase activities were measured in transfected cells with vectors containing 1894 bp fragments, and the lowest luciferase activities were measured in transfected cells with vectors containing 416 bp fragments. Luciferase activities were higher in transfected cells with vectors containing 632 bp fragments than that in transfected cells with vectors containing 1423 bp fragments. Conclusion: The basic transcription\|promoting element (promoter) for SNC6 expression resides between 0 to -337, and two transcription\|enhancing elements (enhancer) resides between -337 to -552 and -1344 to -1814, whereas one transcription\|inhibiting element (silencer) exists between -552 to -1344.
基金Project supported by National Natural Science Foundation of China,No.863 Z2001-04
文摘AIM: To test the hypothesis to block VEGF expression of SMMC-7721 hepatoma cells may inhibit tumor growth using the rat hepatoma model. METHODS: Amplify the 200 VEGF cDNA fragment and insert it into human U6 gene cassette in the reverse orientation transcribing small antisense RNA which could specifically interact with VEGF165, and VEGF121 mRNA. Construct the retroviral vector containing this antisense VEGF U6 cassette and package the replication-deficient recombinant retrovirus. SMMC-7721 cells were transduced with these virus and positive clones were selected with G418. PCR and Southern blot analysis were performed to determine if U6 cassette integrated into the genomic DNA of positive clone. Transfected tumor cells were evaluated for RNA expression by ribonuclease protection assays. The VEGF protein in the supernatant of parental tumor cells and genetically modified tumor cells was determined with ELISA. In vitro and in vivo growth properties of antisense VEGF cell clone in nude mice were analyzed. RESULTS: Restriction enzyme digestion and PCR sequencing verified that the antisense VEGF RNA retroviral vector was successfully constructed.After G418 selection, resistant SMMC-7721 cell clone was picked up. PCR and Southern blot analysis suggested that U6 cassette was integrated into the cell genomic DNA. Stable SMMC-7721 cell clone transduced with U6 antisense RNA cassette could express 200 bp small antisense VEGF RNA and secrete reduced levels of VEGF in culture condition. Production of VEGF by antisense transgene-expressing cells was 65+/-10 ng/L per 10(6) cells, 42045 ng/L per 10(6) cells in sense group and 485+/-30 ng/L per 10(6) cells in the negative control group, (P【 0.05). The antisense-VEGF cell clone appeared phenotypically indistinguishable from SMMC-7721 cells and SMMC-7721 cells transfected sense VEGF. The growth rate of the antisense-VEGF cell clone was the same as the control cells. When S.C. was implanted into nude mice, growth of antisense-VEGF cell lines was greatly inhibited compared with control cells. CONCLUSION: Expression of antisense VEGF RNA in SMMC-7721 cells could decrease the tumorigenicity, and antisense-VEGF gene therapy may be an adjuvant treatment for hepatoma.
基金Fundamental Research Foundation of Sinopec(X505015)
文摘In the current study simultaneous reactions of hydrodesulfurization(HDS) of dibenzothiophene(DBT) and reforming of methanol in a micro-autoclave reactor were studied over bi-metallic(Co-Mo/Al2O3 and Ni-Mo/Al2O3) and tri-metallic(Pd-Co-Mo/Al2O3 and Pd-Ni-Mo/Al2O3) catalyst systems which were prepared by incipient impregnation method.In situ hydrogen utilization and low Pd loadings were the major targets of this study.For comparison purpose,catalytic activity was separately determined for both the methanol reforming and HDS of DBT reactions as well.Ni based catalysts were confirmed with better activity than Co ones for both the reactions with Pd promoted ones ranking at the top i.e.Pd-Ni-Mo/Al2O3 > Ni-Mo/Al2O3 > Pd-Co-Mo/Al2O3 > Co-Mo/Al2O3 where Pd-Ni-Mo/Al2O3 showed 91% DBT conversion at 380 ℃ and 12 h reaction time.Some of the selected organic additives on catalytic activity were tested for their effect toward HDS reaction which was unique with close relation to their chemical nature.Reaction products were quantitatively and qualitatively analyzed via HPLC and GC-MS techniques respectively which helped in elucidating reaction mechanism.
文摘There are a number of factors involved in teaching quality. Among them teaching materials or textbooks are of primary importance, the presentation of which relies first of all on the viewpoint to structure the contents geographically. Whatever branch of geography you are teaching or in pursuit, geographical viewpoint is vitally important. This paper in discussing innovation of geographical education about these institutions with the course of regional physical geography as an example. The higher education of our discipline is in pressing need of innovation and thereby upgrading quality.
文摘Evidence supports the involvement of oxytocin in social behavior. The oxytocin receptor gene (OXTR) has been associated with differences in social brain function and risk for autism. Motivated by recent work, we investigated the effect of variation in the common functional rs2268498 T/C polymorphism in the promoter region of OXTR on neural responses to fear expressions. 46 healthy subjects were divided into genotype groups of C carriers (n = 32) and TT ho-mozygous (n = 14) and neural activity was measured during the recognition of fear and neutral expressions. Results showed that during the recognition of fear expressions, the TT genotype group exhibited increased responding in the inferior occipital gyrus, considered important for face processing, compared to carriers of the C allele (P < 0.005;cluster corrected for whole brain), an effect not found for neutral faces. These results indicate the impact of this OXTR genetic variant on individual differences in social affective neural processing.