This paper examines the effects of internal control mechanisms on the financial distress of publicly listed companies in China. Using t-test and Logistic regression analysis, we investigated the following aspects: own...This paper examines the effects of internal control mechanisms on the financial distress of publicly listed companies in China. Using t-test and Logistic regression analysis, we investigated the following aspects: ownership by top managers and the CEO, the number of directors, the percentage of inside directors, CEO duality, and ownership concentration. The empirical tests indicate a lower probability of financial distress when ownership by top managers and that by the CEO are higher. The evidence also shows that a combination of two parts, the CEO and the chairman of the board, may influence the internal control system of a publicly listed companies.展开更多
Nowdays, the study of measurement of the biological field focuses on the research of improving surface plasmon resonance （SPR） in the fields of integration and detection sensitivity. We designed a kind of grating co...Nowdays, the study of measurement of the biological field focuses on the research of improving surface plasmon resonance （SPR） in the fields of integration and detection sensitivity. We designed a kind of grating connected surface plasmon resonance sensor. Theoretically, we analyzed the wave vector and the. effective refractive index relations with the diffraction grating structure. Then we obtained the nanoparticles enhancement SPR structure with a resolution 10times higher than that of traditional SPR sensors. Also, we used the finite-difference time-domain （FDTD） analysis and simulation which showed that it was obvious with coupling effect by the nanoparticles enhancement SPR structure that the reflectance spectral bandwidth results validated the structure significantly which improved the sensitivity. Experimental results showed that the dynamic response of the designed sensor reached 10^-6 RIU （refractive index unit）. This study has the certain significance to long-distance and special sensing applications.展开更多
2018年起,国家自然科学基金委员会推进科学基金系统性改革,为更好的助力优化学科布局,2019年大气科学学科率先开展了学科申请代码调整,通过广泛的战略研究与研讨形成了2020年度申请代码设置方案,确定了以“分支学科”“支撑技术”和“...2018年起,国家自然科学基金委员会推进科学基金系统性改革,为更好的助力优化学科布局,2019年大气科学学科率先开展了学科申请代码调整,通过广泛的战略研究与研讨形成了2020年度申请代码设置方案,确定了以“分支学科”“支撑技术”和“发展领域”三个板块、共15个“二级申请代码”为主要架构的学科资助体系,并组织专家对各“二级申请代码”的下设研究方向和关键词进行系统梳理和分析,经过三年实施和不断优化形成了当前的版本。本文主要针对D0512地球系统模式发展下设的五个研究方向和关键词进行解读,介绍其设置背景,下设研究方向及关键词的总体框架,并基于科睿唯安Web of Science数据库对该申请代码下不同方向关键词的出现频率和研究热点进行了分析和讨论,发现五个方向的主要关键词基本设置合理,在后续工作中需要继续优化和适当调整,不断扩大影响并吸引更多的优秀申请人,促进我国地球系统模式的发展。展开更多
The objective of this study was to investigate the molecular regulatory mechanism of 1-methylcyclopropene(1-MCP)treatment on leaf yellowing of pak choi during storage at 20°C.In the present study,compared with th...The objective of this study was to investigate the molecular regulatory mechanism of 1-methylcyclopropene(1-MCP)treatment on leaf yellowing of pak choi during storage at 20°C.In the present study,compared with the control and 10μL/L ethylene-treated pak choi,5.0μL/L 1-MCP fumigation alleviated the yellowing process of pak choi as proved by the maintenance of higher levels of colour,chlorophyll content,and appearance.1-MCP treatment decreased chlorophyll breakdown by downregulating the activity of chlorophyll-degrading enzymes(chlorophyll b reductase(CBR)and pheophytinase(PPH))and the expression of their related genes(BcNYC1 and BcPPH).The application of 1-MCP also inhibited the transcript abundance of ethylene biosynthesis and signal transduction genes(BcACO,BcEIN3,and BcERF)and reduced ethylene production,thus helping to maintain the green colour of pak choi;however,ethylene treatment exerted the opposite function.Meanwhile,three transcription factors(BcNAC055,BcMYB44,and BcOBF1)were successfully cloned.Experiments performed using yeast one-hybrid assay,dual-luciferase reporter system and in vivo bioluminescence imaging assay,confirmed that BcNAC055,BcMYB44,and BcOBF1 directly bound to the BcNYC1 promoter.1-MCP inhibited the expression levels of BcNAC055,BcMYB44,BcOBF1,and BcNYC1 during storage,while the application of ethylene activated their expression.In conclusion,1-MCP downregulated the expression of the key chlorophyll degradation gene BcNYC1 by inhibiting the transcript level of its three positive regulators(BcNAC055,BcMYB44,and BcOBF1)and lowered the activity of chlorophyll-degrading enzyme CBR,thereby helping mitigate chlorophyll breakdown to retard leaf yellowing in pak choi.The results of this work extend our understanding of 1-MCP-delayed yellowing in postharvest pak choi.展开更多
Romashkino oil field has large oilfield area, small formation dip, many reservoir layers, wide oil-water transition zone and complicated sedimentary environment. Since development, 3 overall development plannings and ...Romashkino oil field has large oilfield area, small formation dip, many reservoir layers, wide oil-water transition zone and complicated sedimentary environment. Since development, 3 overall development plannings and adjustments of individual block have been established. This achieves a high oil production. However, the recoverable reserves of major oil layer with high production become smaller and smaller and the water cut increases over time, the production ability of oil layer decreases. The development status of oil layer of mining siltstone, oil-water transition zone and oil layer with upswept injected water cannot be changed under present dilute well network condition, because there is no reinforced measurement to water well. This results the low oil production of Romashkino oil field. In order to improve oil production rate and reach the designed oil recovery, Romashkino oil field has been implemented many added cuttings since development. Resent researches about Romashkino oil field show: in later oilfield development stage, sidetrack and lateral drilling horizontal wells technology is very reasonable;formation hydraulic fracturing technology has been widely used in recent years;in tertiary oil recovery, sweep efficiency and flooding efficiency related technologies have been taken. This offers reference and guidance for the effective and reasonable oil field development in later period.展开更多
Background: Ubiquitination plays an essential role in many biological processes, including viral infection, and can be reversed by deubiquitinating enzymes (DUBs). Although some studies discovered that DUBs inhibit or...Background: Ubiquitination plays an essential role in many biological processes, including viral infection, and can be reversed by deubiquitinating enzymes (DUBs). Although some studies discovered that DUBs inhibit or enhance viral infection by various mechanisms, there is lack of information on the role of DUBs in virus regulation, which needs to be further investigated.Methods: Immunoblotting, real-time polymerase chain reaction,in vivo/in vitro deubiquitination, protein immunoprecipitation, immunofluorescence, and co-localization biological techniques were employed to examine the effect of ubiquitin-specific protease 3 (USP3) on APOBEC3G (A3G) stability and human immunodeficiency virus (HIV) replication. To analyse the relationship between USP3 and HIV disease progression, we recruited 20 HIV-infected patients to detect the levels of USP3 and A3G in peripheral blood and analysed their correlation with CD4^(+) T-cell counts. Correlation was estimated by Pearson correlation coefficients (for parametric data).Results: The results demonstrated that USP3 specifically inhibits HIV-1 replication in an A3G-dependent manner. Further investigation found that USP3 stabilized 90% to 95% of A3G expression by deubiquitinating Vif-mediated polyubiquitination and blocking its degradation in an enzyme-dependent manner. It also enhances the A3G messenger RNA (mRNA) level by binding to A3G mRNA and stabilizing it in an enzyme-independent manner. Moreover, USP3 expression was positively correlated with A3G expression (r= 0.5110) and CD4^(+) T-cell counts (r= 0.5083) in HIV-1-infected patients.Conclusions: USP3 restricts HIV-1 viral infections by increasing the expression of the antiviral factor A3G. Therefore, USP3 may be an important target for drug development and serve as a novel therapeutic strategy against viral infections.展开更多
This paper investigates a microwave heating method for the determination of chemical oxygen demand (COD) in seawater. The influences of microwave-power, heating time and standard substances on the results are studied....This paper investigates a microwave heating method for the determination of chemical oxygen demand (COD) in seawater. The influences of microwave-power, heating time and standard substances on the results are studied. Using the proposed method, we analyzed the glucose standard solution, the coefficient of variation being less than 2%. Compared with the traditional electric stove heating method, the results of F-test and T-test showed that there was no significant difference between the two methods, but the microwave method had slightly higher precision and reproducibility than the electric stove method. With the microwave heating method, several seawater samples from Jiaozhou Bay and the South Yellow Sea were also analyzed. The recovery was between 97.5% and 104.3%. This new method has the advantages of shortening the heating time, improving the working efficiency and having simple operation and therefore can be used to analyze the COD in seawater.展开更多
Urban greening, urban forestry and urban green structure planning all look at a city as a unit andintend to improve the status of green space in the city. Even though they are new terms, their concepts haveevolved ove...Urban greening, urban forestry and urban green structure planning all look at a city as a unit andintend to improve the status of green space in the city. Even though they are new terms, their concepts haveevolved over a rather long period. This paper presents a historical review of western concepts for urbangreening since the 1850s. The first aim is to establish an overview of how the urban greening concept hasdeveloped and what the relationships are between the historical concepts and urban greening, urban forestryand urban green structure planning today. The secondary purpose is to understand some key issues for urbangreening through the examination of historical precedents. Based on a literature review, the paper presentsseveral historical concepts for urban greening rampart area planning, park system, green belts, greenwedges and greenways. The new concept of urban green structure is also introduced. Each concept is defined.The social background and the influence on city development are described. The review shows that theconcept of urban greening has a long history, parallel with the development of the city planning concepts.The scope of urban greening has become larger over the past years. The functions of urban green space havechanged from single-purpose to multi-purpose. The study indicates that historical concepts may still giveinspiration in todays urban greening process.展开更多
Some examples of flouting Cooperative Principle (CP) in Chinese people's greeting, requesting, and accepting compliment are presented and the cultural reasons for these violations are explained in this article. By...Some examples of flouting Cooperative Principle (CP) in Chinese people's greeting, requesting, and accepting compliment are presented and the cultural reasons for these violations are explained in this article. By analyzing the Chinese way of flouting CP, the author explores the unique characteristics of CP in Chinese context.展开更多
The effect of peripheral nerve (PN) on neurite outgrowth from retinal explants of adult hamsters was examined. Cultures of retinal explants, and co-cultures of retinal explants and PN were performed using chick retina...The effect of peripheral nerve (PN) on neurite outgrowth from retinal explants of adult hamsters was examined. Cultures of retinal explants, and co-cultures of retinal explants and PN were performed using chick retinal basement membrane (BM) as substrate. The presence of PN increases the number and length of neurite outgrowth. In addition, a high proportion of neurites situated close to PN tend to grow towards it. Since there was no contact between retinal ex-plants and PN, we suggest that PN might secrete diffusible substances to attract the neurites to grow towards it.展开更多
The establishment of a divertor configuration is a task for a divertor tokamak. To achieve this goal, we have to identify plasma boundary at first. So, it is important to find a quick approach to calculate plasma boun...The establishment of a divertor configuration is a task for a divertor tokamak. To achieve this goal, we have to identify plasma boundary at first. So, it is important to find a quick approach to calculate plasma boundary and other global parameters. Various展开更多
文摘This paper examines the effects of internal control mechanisms on the financial distress of publicly listed companies in China. Using t-test and Logistic regression analysis, we investigated the following aspects: ownership by top managers and the CEO, the number of directors, the percentage of inside directors, CEO duality, and ownership concentration. The empirical tests indicate a lower probability of financial distress when ownership by top managers and that by the CEO are higher. The evidence also shows that a combination of two parts, the CEO and the chairman of the board, may influence the internal control system of a publicly listed companies.
基金This work was supported by the National Natural Science Foundation of China （No. 61061006） and Guangxi Normal University Doctor Scientific Research Foundation.
文摘Nowdays, the study of measurement of the biological field focuses on the research of improving surface plasmon resonance （SPR） in the fields of integration and detection sensitivity. We designed a kind of grating connected surface plasmon resonance sensor. Theoretically, we analyzed the wave vector and the. effective refractive index relations with the diffraction grating structure. Then we obtained the nanoparticles enhancement SPR structure with a resolution 10times higher than that of traditional SPR sensors. Also, we used the finite-difference time-domain （FDTD） analysis and simulation which showed that it was obvious with coupling effect by the nanoparticles enhancement SPR structure that the reflectance spectral bandwidth results validated the structure significantly which improved the sensitivity. Experimental results showed that the dynamic response of the designed sensor reached 10^-6 RIU （refractive index unit）. This study has the certain significance to long-distance and special sensing applications.
文摘2018年起,国家自然科学基金委员会推进科学基金系统性改革,为更好的助力优化学科布局,2019年大气科学学科率先开展了学科申请代码调整,通过广泛的战略研究与研讨形成了2020年度申请代码设置方案,确定了以“分支学科”“支撑技术”和“发展领域”三个板块、共15个“二级申请代码”为主要架构的学科资助体系,并组织专家对各“二级申请代码”的下设研究方向和关键词进行系统梳理和分析,经过三年实施和不断优化形成了当前的版本。本文主要针对D0512地球系统模式发展下设的五个研究方向和关键词进行解读,介绍其设置背景,下设研究方向及关键词的总体框架,并基于科睿唯安Web of Science数据库对该申请代码下不同方向关键词的出现频率和研究热点进行了分析和讨论,发现五个方向的主要关键词基本设置合理,在后续工作中需要继续优化和适当调整,不断扩大影响并吸引更多的优秀申请人,促进我国地球系统模式的发展。
基金the National Natural Science Foundation of China(32202127)the Key Project of Jiangsu Province Modern Agriculture(BE2018382)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),China.
文摘The objective of this study was to investigate the molecular regulatory mechanism of 1-methylcyclopropene(1-MCP)treatment on leaf yellowing of pak choi during storage at 20°C.In the present study,compared with the control and 10μL/L ethylene-treated pak choi,5.0μL/L 1-MCP fumigation alleviated the yellowing process of pak choi as proved by the maintenance of higher levels of colour,chlorophyll content,and appearance.1-MCP treatment decreased chlorophyll breakdown by downregulating the activity of chlorophyll-degrading enzymes(chlorophyll b reductase(CBR)and pheophytinase(PPH))and the expression of their related genes(BcNYC1 and BcPPH).The application of 1-MCP also inhibited the transcript abundance of ethylene biosynthesis and signal transduction genes(BcACO,BcEIN3,and BcERF)and reduced ethylene production,thus helping to maintain the green colour of pak choi;however,ethylene treatment exerted the opposite function.Meanwhile,three transcription factors(BcNAC055,BcMYB44,and BcOBF1)were successfully cloned.Experiments performed using yeast one-hybrid assay,dual-luciferase reporter system and in vivo bioluminescence imaging assay,confirmed that BcNAC055,BcMYB44,and BcOBF1 directly bound to the BcNYC1 promoter.1-MCP inhibited the expression levels of BcNAC055,BcMYB44,BcOBF1,and BcNYC1 during storage,while the application of ethylene activated their expression.In conclusion,1-MCP downregulated the expression of the key chlorophyll degradation gene BcNYC1 by inhibiting the transcript level of its three positive regulators(BcNAC055,BcMYB44,and BcOBF1)and lowered the activity of chlorophyll-degrading enzyme CBR,thereby helping mitigate chlorophyll breakdown to retard leaf yellowing in pak choi.The results of this work extend our understanding of 1-MCP-delayed yellowing in postharvest pak choi.
文摘Romashkino oil field has large oilfield area, small formation dip, many reservoir layers, wide oil-water transition zone and complicated sedimentary environment. Since development, 3 overall development plannings and adjustments of individual block have been established. This achieves a high oil production. However, the recoverable reserves of major oil layer with high production become smaller and smaller and the water cut increases over time, the production ability of oil layer decreases. The development status of oil layer of mining siltstone, oil-water transition zone and oil layer with upswept injected water cannot be changed under present dilute well network condition, because there is no reinforced measurement to water well. This results the low oil production of Romashkino oil field. In order to improve oil production rate and reach the designed oil recovery, Romashkino oil field has been implemented many added cuttings since development. Resent researches about Romashkino oil field show: in later oilfield development stage, sidetrack and lateral drilling horizontal wells technology is very reasonable;formation hydraulic fracturing technology has been widely used in recent years;in tertiary oil recovery, sweep efficiency and flooding efficiency related technologies have been taken. This offers reference and guidance for the effective and reasonable oil field development in later period.
基金This work was supported in part by,grants from the National Key R&D Program of China(Nos.2021YFC2301900 and 2301904)the National Natural Science Foundation of China(Nos.81930062,81672004 to ZWY,and 31900457,82272304 to GWY)+2 种基金the Science and Technology Department,of Jilin_Province,(Nos.20190101003JH,20200201422JC,20190201272JC,YDZJ202201ZYTS671,and YDZJ202201ZYTS590)Program of Jilin Finance Department(No.2019SRCJ017)the Key Laboratory of Molecular Virology,Jilin Province(No.20102209).
文摘Background: Ubiquitination plays an essential role in many biological processes, including viral infection, and can be reversed by deubiquitinating enzymes (DUBs). Although some studies discovered that DUBs inhibit or enhance viral infection by various mechanisms, there is lack of information on the role of DUBs in virus regulation, which needs to be further investigated.Methods: Immunoblotting, real-time polymerase chain reaction,in vivo/in vitro deubiquitination, protein immunoprecipitation, immunofluorescence, and co-localization biological techniques were employed to examine the effect of ubiquitin-specific protease 3 (USP3) on APOBEC3G (A3G) stability and human immunodeficiency virus (HIV) replication. To analyse the relationship between USP3 and HIV disease progression, we recruited 20 HIV-infected patients to detect the levels of USP3 and A3G in peripheral blood and analysed their correlation with CD4^(+) T-cell counts. Correlation was estimated by Pearson correlation coefficients (for parametric data).Results: The results demonstrated that USP3 specifically inhibits HIV-1 replication in an A3G-dependent manner. Further investigation found that USP3 stabilized 90% to 95% of A3G expression by deubiquitinating Vif-mediated polyubiquitination and blocking its degradation in an enzyme-dependent manner. It also enhances the A3G messenger RNA (mRNA) level by binding to A3G mRNA and stabilizing it in an enzyme-independent manner. Moreover, USP3 expression was positively correlated with A3G expression (r= 0.5110) and CD4^(+) T-cell counts (r= 0.5083) in HIV-1-infected patients.Conclusions: USP3 restricts HIV-1 viral infections by increasing the expression of the antiviral factor A3G. Therefore, USP3 may be an important target for drug development and serve as a novel therapeutic strategy against viral infections.
文摘This paper investigates a microwave heating method for the determination of chemical oxygen demand (COD) in seawater. The influences of microwave-power, heating time and standard substances on the results are studied. Using the proposed method, we analyzed the glucose standard solution, the coefficient of variation being less than 2%. Compared with the traditional electric stove heating method, the results of F-test and T-test showed that there was no significant difference between the two methods, but the microwave method had slightly higher precision and reproducibility than the electric stove method. With the microwave heating method, several seawater samples from Jiaozhou Bay and the South Yellow Sea were also analyzed. The recovery was between 97.5% and 104.3%. This new method has the advantages of shortening the heating time, improving the working efficiency and having simple operation and therefore can be used to analyze the COD in seawater.
文摘Urban greening, urban forestry and urban green structure planning all look at a city as a unit andintend to improve the status of green space in the city. Even though they are new terms, their concepts haveevolved over a rather long period. This paper presents a historical review of western concepts for urbangreening since the 1850s. The first aim is to establish an overview of how the urban greening concept hasdeveloped and what the relationships are between the historical concepts and urban greening, urban forestryand urban green structure planning today. The secondary purpose is to understand some key issues for urbangreening through the examination of historical precedents. Based on a literature review, the paper presentsseveral historical concepts for urban greening rampart area planning, park system, green belts, greenwedges and greenways. The new concept of urban green structure is also introduced. Each concept is defined.The social background and the influence on city development are described. The review shows that theconcept of urban greening has a long history, parallel with the development of the city planning concepts.The scope of urban greening has become larger over the past years. The functions of urban green space havechanged from single-purpose to multi-purpose. The study indicates that historical concepts may still giveinspiration in todays urban greening process.
文摘Some examples of flouting Cooperative Principle (CP) in Chinese people's greeting, requesting, and accepting compliment are presented and the cultural reasons for these violations are explained in this article. By analyzing the Chinese way of flouting CP, the author explores the unique characteristics of CP in Chinese context.
文摘The effect of peripheral nerve (PN) on neurite outgrowth from retinal explants of adult hamsters was examined. Cultures of retinal explants, and co-cultures of retinal explants and PN were performed using chick retinal basement membrane (BM) as substrate. The presence of PN increases the number and length of neurite outgrowth. In addition, a high proportion of neurites situated close to PN tend to grow towards it. Since there was no contact between retinal ex-plants and PN, we suggest that PN might secrete diffusible substances to attract the neurites to grow towards it.
文摘The establishment of a divertor configuration is a task for a divertor tokamak. To achieve this goal, we have to identify plasma boundary at first. So, it is important to find a quick approach to calculate plasma boundary and other global parameters. Various
