We used a proteomic approach to identify IbpA in Cronobacter sakazokii (C. sakazaki), which is related to heat tolerance in this strain. The abundance of IbpA in C. sakazakii strains strongly increased after heat sh...We used a proteomic approach to identify IbpA in Cronobacter sakazokii (C. sakazaki), which is related to heat tolerance in this strain. The abundance of IbpA in C. sakazakii strains strongly increased after heat shock. C sakazakii CMCC 45402 ibpA deletion mutants were successfully constructed. The C. sakazakii CMCC 45402 AibpA and wild-type strains could not be distinguished based on colony morphology on LB agar plates or biochemical assays. The growth of the C. sakazakii CMCC 45402 AibpA mutant in heat shock conditions was indistinguishable from that of the isogenic wild-type, but showed greater heat resistance than E. coil O157:H7 strain CMCC 44828. This study suggests that the absence of a single ibpA gene has no obvious effect on the phenotype or heat resistance of the strain C. sakazakii CMCC 45402.展开更多
Ⅰ. Introduction “If the school is sensitive to the problems of less successful learners, if it takes steps within its organization, methodology and curriculum to meet their needs, and if individual progress is empha...Ⅰ. Introduction “If the school is sensitive to the problems of less successful learners, if it takes steps within its organization, methodology and curriculum to meet their needs, and if individual progress is emphasized rather than achievement of norms and examination successes, the number of individuals whose learning difficulties become special educational needs may be minimized”(Fish, 1985,p26). As is suggested in this quotation, the 1980s witnessed展开更多
The relations of oxygen content, critical temperature TC and mean ionization potential < U0> of superconducting oxides are reported. We found that in oxides oxygen is the major element which governs their < U...The relations of oxygen content, critical temperature TC and mean ionization potential < U0> of superconducting oxides are reported. We found that in oxides oxygen is the major element which governs their < U0> te values and thus oxygen content plays an jmportant role in their superconducting properties. As for Y(123)- and T1-systems oxygenation may improve their TC values, but for Biand Hg-systems oxygenation process is not so important. In Y(123), as the oxygen content increase results in the increase of TC upon < U0>to, while the substitution of Ba2+ by Sr2+ causes the decrease of TC upon < U0 >. These results may provide some clues about the superconductivity of oxides and support further that < Uo > is really a good criterion for oxide superconductivity. Two kinds of possible superconducting oxides are predicted in this paper according to the mean ionization potential criterion.展开更多
In this letter, the preparation of three ZrO2 phases has beed briefly described and their catalytic results have been presented for CO hydrogenation to olefin. These catalysts had a good selectivity for light olefin. ...In this letter, the preparation of three ZrO2 phases has beed briefly described and their catalytic results have been presented for CO hydrogenation to olefin. These catalysts had a good selectivity for light olefin. Monoclinic ZrO2 catalyst had a high selectivity for isobutene, while the other phase catalysts had not展开更多
Objective To study the relationship between serum uric acid and insulin resistance in type 2 diabetic patients.Methods A total of 728 middle-aged and elderly type 2 diabetic patients were recruited and the anthropomet...Objective To study the relationship between serum uric acid and insulin resistance in type 2 diabetic patients.Methods A total of 728 middle-aged and elderly type 2 diabetic patients were recruited and the anthropometric,clinical and biochemical parameters and展开更多
Objective To investigate the correlation between serum uric acid(SUA)level and early-phase insulin secretion in subjects with normal glucose regulation(NGR).Methods Totally 367 community NGR residents confirmed by a 7...Objective To investigate the correlation between serum uric acid(SUA)level and early-phase insulin secretion in subjects with normal glucose regulation(NGR).Methods Totally 367 community NGR residents confirmed by a 75g oral glucose tolerance test were enrolled.展开更多
Objective To investigate the genotype-phenotype correlation in Chinese familial hypertrophic cardiomyopathy(HCM)focusing on the cardiac troponic C gene TNNC1 c.G175C mutation.Methods All family members of a Chinese pe...Objective To investigate the genotype-phenotype correlation in Chinese familial hypertrophic cardiomyopathy(HCM)focusing on the cardiac troponic C gene TNNC1 c.G175C mutation.Methods All family members of a Chinese pedigree with hypertrophic cardiomyopathy admitted in Third People’s Hospital of Qingdao展开更多
Objective To explore the association between the Cp G methylation level of positive regulatory domain containing 16(PRDM16)gene promoter and obesity or body mass index(BMI).Methods A total of 116 patients(91female adu...Objective To explore the association between the Cp G methylation level of positive regulatory domain containing 16(PRDM16)gene promoter and obesity or body mass index(BMI).Methods A total of 116 patients(91female adults and 25 male adults)with abdominal operation in a municipal hospital of Henan province were enrolled in this study and they were divided into展开更多
A retention prediction system(RPS)of seven O-ethyl N-isopropyl phosphoro(thioureido)- thioates in reversed phase HPLC was investigated.The system is based on the solvent selectivity triangle concept.Three molecular st...A retention prediction system(RPS)of seven O-ethyl N-isopropyl phosphoro(thioureido)- thioates in reversed phase HPLC was investigated.The system is based on the solvent selectivity triangle concept.Three molecular structure parameters(hydrophobicity Ⅱ,substituent length L, and substituent maximum width B_5)were used to describe the quantitative structure-retention relation- ships.With these quantitative relationships,the retention behaviours of other eight homologs for different mobile phase composition were predicted.The predicted values were consistent with the measured values within relative error of 10%,which means that it is possible to apply the reported method to predict retention values for qualitative purposes for different mobile phase compositions.展开更多
The correlation coefficients of random variables of mechanical structures are generally chosen with experience or even ignored,which cannot actually reflect the effects of parameter uncertainties on reliability.To dis...The correlation coefficients of random variables of mechanical structures are generally chosen with experience or even ignored,which cannot actually reflect the effects of parameter uncertainties on reliability.To discuss the selection problem of the correlation coefficients from the reliability-based sensitivity point of view,the theory principle of the problem is established based on the results of the reliability sensitivity,and the criterion of correlation among random variables is shown.The values of the correlation coefficients are obtained according to the proposed principle and the reliability sensitivity problem is discussed.Numerical studies have shown the following results:(1) If the sensitivity value of correlation coefficient ρ is less than(at what magnitude 0.000 01),then the correlation could be ignored,which could simplify the procedure without introducing additional error.(2) However,as the difference between ρs,that is the most sensitive to the reliability,and ρR,that is with the smallest reliability,is less than 0.001,ρs is suggested to model the dependency of random variables.This could ensure the robust quality of system without the loss of safety requirement.(3) In the case of |Eabs|ρ0.001 and also |Erel|ρ0.001,ρR should be employed to quantify the correlation among random variables in order to ensure the accuracy of reliability analysis.Application of the proposed approach could provide a practical routine for mechanical design and manufactory to study the reliability and reliability-based sensitivity of basic design variables in mechanical reliability analysis and design.展开更多
Objective:To explore the value and feasibility of real-time three-dimensional echocardiography(RT-3DE)in evaluating left ventricular function in patients with different degrees of heart failure.Methods:The 60 heart fa...Objective:To explore the value and feasibility of real-time three-dimensional echocardiography(RT-3DE)in evaluating left ventricular function in patients with different degrees of heart failure.Methods:The 60 heart failure patients in the case group were divided into three subgroups according to the New York Heart Association(NYHA)classification:12 cases of cardiac function gradeⅡ,35 cases of cardiac function gradeⅢ,13 cases of cardiac function grade IV,and the other 30 cases of healthy subjects as control group.Compare the left ventricular end-diastolic volume(LVEDV),left ventricular end-systolic volume(LVESV),left ventricular ejection fraction(LVEF),and left ventricular 16,12,and 6 segments reaching the minimum systolic volume time standard deviation standardized value(Tmsv SD%),left ventricular 16,12 and 6 segments reaching the minimum systolic volume time standardized values of the maximum difference(Tmsv DIF%),analysis of the correlation between the above left ventricular function-related parameters and cardiac function grading.Results:(1)There were statistically significant differences in LVEDV and LVESV between each group(p<0.001).There was no statistically significant difference in LVEF between the cardiac function gradeⅡgroup and the control group,and between the grade IV group and the gradeⅢgroup(p=0.094 and 0.246).(2)compared with the control group,all parameters related to RT-3DE evaluation of left ventricular synchronization were prolonged in the case group,and the difference was statistically significant(p<0.001).The differences of Tmsv 16-SD%and Tmsv 16-DIF%in each subgroup of the case group were statistically significant(p<0.001).(3)LVEF was negatively correlated with NYHA classification of cardiac function(rs=-0.779,p<0.001),and LVEDV,LVESV,Tmsv 16-SD%,Tmsv 12-SD%,Tmsv 6-SD%,Tmsv 16-DIF%,Tmsv 12-DIF%,Tmsv 6-DIF%were positively correlated with NYHA function classification,showing strong correlation(rs=0.710,0.785,0.885,0.675,0.605,0.885,0.695,0.622,p<0.001),among them,Tmsv 16-SD%and Tmsv 16-Dif%have the highest correlation.Conclusion:RT-3DE can comprehensively evaluate the impairment of cardiac function.The measured parameters of left ventricular function are strongly correlated with cardiac function classification,which has impo-rtant application value for clinical judgment of the severity of heartfailure.展开更多
It was all known that Lhasa went through a high temperature of 30.8℃in late June 2019,which hit record highs.To better understand the reasons,based on observations recorded at automatic weather stations in Lhasa,the ...It was all known that Lhasa went through a high temperature of 30.8℃in late June 2019,which hit record highs.To better understand the reasons,based on observations recorded at automatic weather stations in Lhasa,the characteristics of temperature variation at multiple time scales were studied using the linear trend method,Mann-Kendall mutation test,Morlet wavelet analysis,R/S analysis and so on.The results showed that:(a)the annual mean temperature(AMT)is rising at a rate of 0.5℃/10 a,and the average temperature for different seasons also increased significantly,especially in winter.(b)Although there was an intersection in 1995,it was found that AMT,did not pass the reliability test of significance levelα=0.05,this means there are no abrupt changes for AMT,the values are 7.97 and 9.15℃respectively before and after the intersection point.(c)AMT has a periodic oscillation for 18-25 and 25-32 a based on a mass of data and the wavelet variance diagrams in Lhasa.AMT has a main cycle of 28 a,cyclic patterns of temperature changes in spring,summer and autumn is similar to AMT,but it is relatively complex in winter.(d)The Hurst index of AMT and different seasons demonstrates that the temperature is likely to continue to rise in the future in Lhasa.展开更多
The pressure fluctuation in a large jetting fluidized bed with a vertical nozzle was examined based on deterministic chaos theory. The effects of the jetting gas velocity and the static bed height on the correlation d...The pressure fluctuation in a large jetting fluidized bed with a vertical nozzle was examined based on deterministic chaos theory. The effects of the jetting gas velocity and the static bed height on the correlation dimension were investigated. The correlation dimension increased with increasing jet gas velocity. At the same jet gas velocity, the higher the static bed height, the greater the correlation dimension is. The variations of correlation dimension and standard deviation of pressure fluctuation with gas jet velocity exhibited a similar shape and trend.展开更多
In 2006, Duman et al. proposed “Neurotrophic Theory of Depression” [1]. According to the hypothesis, stress leads to a decrease in the expression of neurotrophic factors such as Brain-derived neurotrophic factor (BD...In 2006, Duman et al. proposed “Neurotrophic Theory of Depression” [1]. According to the hypothesis, stress leads to a decrease in the expression of neurotrophic factors such as Brain-derived neurotrophic factor (BDNF) in the limbic structure, and antidepressant therapy can partially reverse the effect caused by stress. The reduction of BDNF and other neurotrophic factors promotes the atrophy of certain brain structures, especially the hippocampus and prefrontal cortex, while antidepressant treatment increases the level of BDNF in the brain, and improves synaptic plasticity and neuronal survival in related brain regions. Neurotrophic factors are a class of molecules that act on the nervous system and play an important role in maintaining cell function. They can regulate the growth, survival, differentiation and cell cycle of nerve cells. There is a hypothesis of neuroendocrine dysfunction in the neurobiochemical mechanism of depression, which is mainly the abnormal activity of the hypothalamic-pituitary-adrenal axis (HPA) and hypothalamic-pituitary-thyroid axis (HPT). This article reviews the related research on depression and brain-derived neurotrophic factors in order to guide clinical research and treatment.展开更多
The properties of wood can be improved through steam-heat treatment.There are many studies about mechanical properties of steam-heat treated wood,but very few studies are on the aspects of chemical modifications.In th...The properties of wood can be improved through steam-heat treatment.There are many studies about mechanical properties of steam-heat treated wood,but very few studies are on the aspects of chemical modifications.In this study,FT-IR spectra combined with SD-IR spectra,correlation coefficients and 2DIR spectra are employed to analyze the chemical modifications of teak[Tectona grandis L.F.) wood during steam-heat treatment under treatment temperatures from 120 ℃ to 220 ℃ at intervals of 20 ℃.Acetic acid,which is produced during steam-heat treatment,acts as a catalyst of condensation and degradation reactions of wood components.The changes of wood components are more and more intense with increasing the treatment temperature.The sensitivity of wood samples to thermal perturbation rises initially with increasing treatment temperature before falling back.The steam-heat treated wood under180℃ is the most sensitive.展开更多
In this paper,we focus on the BDS test,which is a nonparametric test of independence.Specifically,the null hypothesis H0 of it is that {u_(t)} is i.i.d.(independent and identically distributed),where {u_(t)} is a rand...In this paper,we focus on the BDS test,which is a nonparametric test of independence.Specifically,the null hypothesis H0 of it is that {u_(t)} is i.i.d.(independent and identically distributed),where {u_(t)} is a random sequence.The BDS test is widely used in economics and finance,but it has a weakness that cannot be ignored:over-rejecting H0 even if the length T of {u_(t)} is as large as(100;2000).To improve the over-rejection problem of BDS test,considering that the correlation integral is the foundation of this test,we not only accurately describe the expectation of the correlation integral under H_(0),but also calculate all terms of the asymptotic variance of the correlation integral whose order is O(T^(-1))and O(T^(-2)),which is essential to improve the finite sample performance of BDS test.Based on this,we propose a revised BDS(RBDS)test and prove its asymptotic normality under H0.The RBDS test not only inherits all the advantages of BDS test,but also effectively corrects the over-rejection problem of it,which can be fully confirmed by the simulation results we presented.Moreover,based on the simulation results,we find that similar to BDS test,RBDS test would also be affected by the parameter estimations of the ARCH-type model,resulting in size distortion,but this phenomenon can be alleviated by the logarithmic transformation preprocessing of the estimate residuals of the model.Besides,through some actual datasets that have been demonstrated to fit well with ARCH-type models,we also compared the performance of BDS test and RBDS test in evaluating the goodness-of-fit of the model in empirical problem,and the results reflect that,under the same condition,the performance of the RBDS test is more encouraging.展开更多
基金funded by National Science and Technology Major Project of the Ministry of Science and Technology of China(2013ZX09304101)
文摘We used a proteomic approach to identify IbpA in Cronobacter sakazokii (C. sakazaki), which is related to heat tolerance in this strain. The abundance of IbpA in C. sakazakii strains strongly increased after heat shock. C sakazakii CMCC 45402 ibpA deletion mutants were successfully constructed. The C. sakazakii CMCC 45402 AibpA and wild-type strains could not be distinguished based on colony morphology on LB agar plates or biochemical assays. The growth of the C. sakazakii CMCC 45402 AibpA mutant in heat shock conditions was indistinguishable from that of the isogenic wild-type, but showed greater heat resistance than E. coil O157:H7 strain CMCC 44828. This study suggests that the absence of a single ibpA gene has no obvious effect on the phenotype or heat resistance of the strain C. sakazakii CMCC 45402.
文摘Ⅰ. Introduction “If the school is sensitive to the problems of less successful learners, if it takes steps within its organization, methodology and curriculum to meet their needs, and if individual progress is emphasized rather than achievement of norms and examination successes, the number of individuals whose learning difficulties become special educational needs may be minimized”(Fish, 1985,p26). As is suggested in this quotation, the 1980s witnessed
文摘The relations of oxygen content, critical temperature TC and mean ionization potential < U0> of superconducting oxides are reported. We found that in oxides oxygen is the major element which governs their < U0> te values and thus oxygen content plays an jmportant role in their superconducting properties. As for Y(123)- and T1-systems oxygenation may improve their TC values, but for Biand Hg-systems oxygenation process is not so important. In Y(123), as the oxygen content increase results in the increase of TC upon < U0>to, while the substitution of Ba2+ by Sr2+ causes the decrease of TC upon < U0 >. These results may provide some clues about the superconductivity of oxides and support further that < Uo > is really a good criterion for oxide superconductivity. Two kinds of possible superconducting oxides are predicted in this paper according to the mean ionization potential criterion.
文摘In this letter, the preparation of three ZrO2 phases has beed briefly described and their catalytic results have been presented for CO hydrogenation to olefin. These catalysts had a good selectivity for light olefin. Monoclinic ZrO2 catalyst had a high selectivity for isobutene, while the other phase catalysts had not
文摘Objective To study the relationship between serum uric acid and insulin resistance in type 2 diabetic patients.Methods A total of 728 middle-aged and elderly type 2 diabetic patients were recruited and the anthropometric,clinical and biochemical parameters and
文摘Objective To investigate the correlation between serum uric acid(SUA)level and early-phase insulin secretion in subjects with normal glucose regulation(NGR).Methods Totally 367 community NGR residents confirmed by a 75g oral glucose tolerance test were enrolled.
文摘Objective To investigate the genotype-phenotype correlation in Chinese familial hypertrophic cardiomyopathy(HCM)focusing on the cardiac troponic C gene TNNC1 c.G175C mutation.Methods All family members of a Chinese pedigree with hypertrophic cardiomyopathy admitted in Third People’s Hospital of Qingdao
文摘Objective To explore the association between the Cp G methylation level of positive regulatory domain containing 16(PRDM16)gene promoter and obesity or body mass index(BMI).Methods A total of 116 patients(91female adults and 25 male adults)with abdominal operation in a municipal hospital of Henan province were enrolled in this study and they were divided into
文摘A retention prediction system(RPS)of seven O-ethyl N-isopropyl phosphoro(thioureido)- thioates in reversed phase HPLC was investigated.The system is based on the solvent selectivity triangle concept.Three molecular structure parameters(hydrophobicity Ⅱ,substituent length L, and substituent maximum width B_5)were used to describe the quantitative structure-retention relation- ships.With these quantitative relationships,the retention behaviours of other eight homologs for different mobile phase composition were predicted.The predicted values were consistent with the measured values within relative error of 10%,which means that it is possible to apply the reported method to predict retention values for qualitative purposes for different mobile phase compositions.
基金supported by Changjiang Scholars and Innovative Research Team in University of China (Grant No. IRT0816)Key National Science & Technology Special Project on "High-Grade CNC Machine Tools and Basic Manufacturing Equipments" of China (Grant No. 2010ZX04014-014)+1 种基金National Natural Science Foundation of China (Grant No. 50875039)Key Projects in National Science & Technology Pillar Program during the 11th Five-year Plan Period of China (Grant No. 2009BAG12A02-A07-2)
文摘The correlation coefficients of random variables of mechanical structures are generally chosen with experience or even ignored,which cannot actually reflect the effects of parameter uncertainties on reliability.To discuss the selection problem of the correlation coefficients from the reliability-based sensitivity point of view,the theory principle of the problem is established based on the results of the reliability sensitivity,and the criterion of correlation among random variables is shown.The values of the correlation coefficients are obtained according to the proposed principle and the reliability sensitivity problem is discussed.Numerical studies have shown the following results:(1) If the sensitivity value of correlation coefficient ρ is less than(at what magnitude 0.000 01),then the correlation could be ignored,which could simplify the procedure without introducing additional error.(2) However,as the difference between ρs,that is the most sensitive to the reliability,and ρR,that is with the smallest reliability,is less than 0.001,ρs is suggested to model the dependency of random variables.This could ensure the robust quality of system without the loss of safety requirement.(3) In the case of |Eabs|ρ0.001 and also |Erel|ρ0.001,ρR should be employed to quantify the correlation among random variables in order to ensure the accuracy of reliability analysis.Application of the proposed approach could provide a practical routine for mechanical design and manufactory to study the reliability and reliability-based sensitivity of basic design variables in mechanical reliability analysis and design.
基金Scientific research project of Anhui University of traditional Chinese medicine(No.2018zryb27)2018 key research and development plan project of Anhui Province(No.1804h080248)
文摘Objective:To explore the value and feasibility of real-time three-dimensional echocardiography(RT-3DE)in evaluating left ventricular function in patients with different degrees of heart failure.Methods:The 60 heart failure patients in the case group were divided into three subgroups according to the New York Heart Association(NYHA)classification:12 cases of cardiac function gradeⅡ,35 cases of cardiac function gradeⅢ,13 cases of cardiac function grade IV,and the other 30 cases of healthy subjects as control group.Compare the left ventricular end-diastolic volume(LVEDV),left ventricular end-systolic volume(LVESV),left ventricular ejection fraction(LVEF),and left ventricular 16,12,and 6 segments reaching the minimum systolic volume time standard deviation standardized value(Tmsv SD%),left ventricular 16,12 and 6 segments reaching the minimum systolic volume time standardized values of the maximum difference(Tmsv DIF%),analysis of the correlation between the above left ventricular function-related parameters and cardiac function grading.Results:(1)There were statistically significant differences in LVEDV and LVESV between each group(p<0.001).There was no statistically significant difference in LVEF between the cardiac function gradeⅡgroup and the control group,and between the grade IV group and the gradeⅢgroup(p=0.094 and 0.246).(2)compared with the control group,all parameters related to RT-3DE evaluation of left ventricular synchronization were prolonged in the case group,and the difference was statistically significant(p<0.001).The differences of Tmsv 16-SD%and Tmsv 16-DIF%in each subgroup of the case group were statistically significant(p<0.001).(3)LVEF was negatively correlated with NYHA classification of cardiac function(rs=-0.779,p<0.001),and LVEDV,LVESV,Tmsv 16-SD%,Tmsv 12-SD%,Tmsv 6-SD%,Tmsv 16-DIF%,Tmsv 12-DIF%,Tmsv 6-DIF%were positively correlated with NYHA function classification,showing strong correlation(rs=0.710,0.785,0.885,0.675,0.605,0.885,0.695,0.622,p<0.001),among them,Tmsv 16-SD%and Tmsv 16-Dif%have the highest correlation.Conclusion:RT-3DE can comprehensively evaluate the impairment of cardiac function.The measured parameters of left ventricular function are strongly correlated with cardiac function classification,which has impo-rtant application value for clinical judgment of the severity of heartfailure.
基金the National Natural Science Foundation of China(11803024,11747128)the Natural Science Foundation of Tibet,People's Republic of China(XZ2019ZRG-163)+2 种基金the College Students Innovative Training Plan Program,Hefei Institute of Physical Science,Chinese Academy of Sciences(CASHIPS027)the College Students Innovative Training Plan Program of Chinese Academy of Sciences(20204001929)the College Students Innovative Entrepreneurial Training Plan Program of Tibet University(2020XCX010).
文摘It was all known that Lhasa went through a high temperature of 30.8℃in late June 2019,which hit record highs.To better understand the reasons,based on observations recorded at automatic weather stations in Lhasa,the characteristics of temperature variation at multiple time scales were studied using the linear trend method,Mann-Kendall mutation test,Morlet wavelet analysis,R/S analysis and so on.The results showed that:(a)the annual mean temperature(AMT)is rising at a rate of 0.5℃/10 a,and the average temperature for different seasons also increased significantly,especially in winter.(b)Although there was an intersection in 1995,it was found that AMT,did not pass the reliability test of significance levelα=0.05,this means there are no abrupt changes for AMT,the values are 7.97 and 9.15℃respectively before and after the intersection point.(c)AMT has a periodic oscillation for 18-25 and 25-32 a based on a mass of data and the wavelet variance diagrams in Lhasa.AMT has a main cycle of 28 a,cyclic patterns of temperature changes in spring,summer and autumn is similar to AMT,but it is relatively complex in winter.(d)The Hurst index of AMT and different seasons demonstrates that the temperature is likely to continue to rise in the future in Lhasa.
基金Supported by the National Natural Science Foundation of China(No.29476262)
文摘The pressure fluctuation in a large jetting fluidized bed with a vertical nozzle was examined based on deterministic chaos theory. The effects of the jetting gas velocity and the static bed height on the correlation dimension were investigated. The correlation dimension increased with increasing jet gas velocity. At the same jet gas velocity, the higher the static bed height, the greater the correlation dimension is. The variations of correlation dimension and standard deviation of pressure fluctuation with gas jet velocity exhibited a similar shape and trend.
文摘In 2006, Duman et al. proposed “Neurotrophic Theory of Depression” [1]. According to the hypothesis, stress leads to a decrease in the expression of neurotrophic factors such as Brain-derived neurotrophic factor (BDNF) in the limbic structure, and antidepressant therapy can partially reverse the effect caused by stress. The reduction of BDNF and other neurotrophic factors promotes the atrophy of certain brain structures, especially the hippocampus and prefrontal cortex, while antidepressant treatment increases the level of BDNF in the brain, and improves synaptic plasticity and neuronal survival in related brain regions. Neurotrophic factors are a class of molecules that act on the nervous system and play an important role in maintaining cell function. They can regulate the growth, survival, differentiation and cell cycle of nerve cells. There is a hypothesis of neuroendocrine dysfunction in the neurobiochemical mechanism of depression, which is mainly the abnormal activity of the hypothalamic-pituitary-adrenal axis (HPA) and hypothalamic-pituitary-thyroid axis (HPT). This article reviews the related research on depression and brain-derived neurotrophic factors in order to guide clinical research and treatment.
基金sponsored by the National Natural Science Foundation of China(No.31270591)Province-Academy Cooperation Project of Zhejiang Province and Chinese Academy of Forestry(No.2013SY01)
文摘The properties of wood can be improved through steam-heat treatment.There are many studies about mechanical properties of steam-heat treated wood,but very few studies are on the aspects of chemical modifications.In this study,FT-IR spectra combined with SD-IR spectra,correlation coefficients and 2DIR spectra are employed to analyze the chemical modifications of teak[Tectona grandis L.F.) wood during steam-heat treatment under treatment temperatures from 120 ℃ to 220 ℃ at intervals of 20 ℃.Acetic acid,which is produced during steam-heat treatment,acts as a catalyst of condensation and degradation reactions of wood components.The changes of wood components are more and more intense with increasing the treatment temperature.The sensitivity of wood samples to thermal perturbation rises initially with increasing treatment temperature before falling back.The steam-heat treated wood under180℃ is the most sensitive.
基金the National Natural Science Foundation of China(12271536,12171198)First Class Discipline of Zhejiang-A(Zhejiang University of Finance and Economics-Statistics)(10344921011/003).
文摘In this paper,we focus on the BDS test,which is a nonparametric test of independence.Specifically,the null hypothesis H0 of it is that {u_(t)} is i.i.d.(independent and identically distributed),where {u_(t)} is a random sequence.The BDS test is widely used in economics and finance,but it has a weakness that cannot be ignored:over-rejecting H0 even if the length T of {u_(t)} is as large as(100;2000).To improve the over-rejection problem of BDS test,considering that the correlation integral is the foundation of this test,we not only accurately describe the expectation of the correlation integral under H_(0),but also calculate all terms of the asymptotic variance of the correlation integral whose order is O(T^(-1))and O(T^(-2)),which is essential to improve the finite sample performance of BDS test.Based on this,we propose a revised BDS(RBDS)test and prove its asymptotic normality under H0.The RBDS test not only inherits all the advantages of BDS test,but also effectively corrects the over-rejection problem of it,which can be fully confirmed by the simulation results we presented.Moreover,based on the simulation results,we find that similar to BDS test,RBDS test would also be affected by the parameter estimations of the ARCH-type model,resulting in size distortion,but this phenomenon can be alleviated by the logarithmic transformation preprocessing of the estimate residuals of the model.Besides,through some actual datasets that have been demonstrated to fit well with ARCH-type models,we also compared the performance of BDS test and RBDS test in evaluating the goodness-of-fit of the model in empirical problem,and the results reflect that,under the same condition,the performance of the RBDS test is more encouraging.