In this short review paper, the significant and profound impacts of the Chou’s “invariance theorem” have been briefly presented with crystal clear convincingness.
The prediction of the fracture plane orientation in fatigue is a scientific topic and remains relevant for every type of material. However, in this work, we compared the orientation of the fracture plane obtained expe...The prediction of the fracture plane orientation in fatigue is a scientific topic and remains relevant for every type of material. However, in this work, we compared the orientation of the fracture plane obtained experimentally through tests on specimens under multiaxial loading with that calculated by the variance method. In the statistical approach criteria, several methods have been developed but we have presented only one method, namely the variance method using the equivalent stress. She assumes that the fracture plane orientation is the one on which the variance of the equivalent stress is maximum. Three types of equivalent stress are defined for this method [1]: normal stress, shear stress and combined normal and shear stress. The results obtained were compared with experimental results for multiaxial cyclic stress states, and it emerges that the variance method for the case of combined loading is conservative as it gives a better prediction of the fracture plane.展开更多
Working toward an efficient duration and timeline for the preconstruction phase should be one of the main objectives for project owners.Failing to plan for and coordinate preconstruction decisions in order to control ...Working toward an efficient duration and timeline for the preconstruction phase should be one of the main objectives for project owners.Failing to plan for and coordinate preconstruction decisions in order to control preconstruction duration and manage time variances can lead to financial insecurities,incomplete contract documents,permitting issues,and unrealistic schedules and resource allocation during this phase.To minimize time variances and ensure a productive decision-making process,project owners should be familiar with critical elements in a project that cause variances in the preconstruction phase timeline.In this study,the impacts of eleven critical preconstruction elements on time variances were analyzed.These eleven preconstruction elements are considered critical in how they impact time variances during the preconstruction phase.They were determined to be critical based either on significantly impacting time variance during the preconstruction phase or believed to be critical from findings from previous studies,however,the findings from this study showed no significant impact on the time variances.In most previous studies focusing on the elements impacting project schedules,data were collected by surveying construction professionals.In this study,objective and quantitative data related to project preconstruction elements were used as opposed to self-reported data.Using the results of this study,project owners and stakeholders will be able to evaluate the critical preconstruction elements impacting the timing of their projects and prioritize decisions related to the critical elements early on during the preconstruction phase.展开更多
The valuation of financial derivatives often assumes risk neutrality with respect to the risk-neutral martingale measure,which prevents arbitrage opportunities.However,casual traders may still incur substantial losses...The valuation of financial derivatives often assumes risk neutrality with respect to the risk-neutral martingale measure,which prevents arbitrage opportunities.However,casual traders may still incur substantial losses when trading at this risk-neutral price,especially when the price has to be paid now and the payoff is only realized in the future.This study proposes a new valuation framework that provides risksensitive investors with an additional safeguard.The proposed framework embraces a worst-case perspective while exploiting the underlier’s stochastic process,representing a combination of robust optimization and stochastic programming.Notably,it aims to mitigate losses in the likelier scenarios of the underlying asset’s prices.When the underlier’s returns are independent and lognormally but not necessarily identically distributed,our approach for pricing variance and volatility swaps could be greatly simplified,benefit from parallel computing,and be solved by a two-dimensional grid search.We further derive a closed-form solution in some special stationary cases and provide experimental results to highlight the effect of risk aversion on fending off sizable trading losses.展开更多
Significant wave period is an important parameter in coastal and offshore engineering design.Traditional spectral wave models do not directly calculate this parameter,which means that it needs to be estimated from the...Significant wave period is an important parameter in coastal and offshore engineering design.Traditional spectral wave models do not directly calculate this parameter,which means that it needs to be estimated from the spectral periods using empirical formulas.The wave energy period is one of the wave periods directly output by many wave models and is often used in studies of wave energy.This study investigated the relationship between significant wave period and wave energy period using wave data measured at three stations in the coastal waters of China.The observations recorded at these stations in the South China Sea,the East China Sea,and the Bohai Sea covered a wide range of surface wave conditions.Analysis indicated that the ratio of significant wave period to wave energy period is closely related to the Goda peakedness parameter of the wave spectra.Therefore,we proposed an empirical formula in which significant wave period is a function of wave energy period and the Goda peakedness parameter.Evaluation results showed that the performance of this formula is substantially better than that of fitting formulas that use constant coefficients.展开更多
In the variance component estimation(VCE)of geodetic data,the problem of negative VCE is likely to occur.In the ordinary additive error model,there have been related studies to solve the problem of negative variance c...In the variance component estimation(VCE)of geodetic data,the problem of negative VCE is likely to occur.In the ordinary additive error model,there have been related studies to solve the problem of negative variance components.However,there is still no related research in the mixed additive and multiplicative random error model(MAMREM).Based on the MAMREM,this paper applies the nonnegative least squares variance component estimation(NNLS-VCE)algorithm to this model.The correlation formula and iterative algorithm of NNLS-VCE for MAMREM are derived.The problem of negative variance in VCE for MAMREM is solved.This paper uses the digital simulation example and the Digital Terrain Mode(DTM)to prove the proposed algorithm's validity.The experimental results demonstrated that the proposed algorithm can effectively correct the VCE in MAMREM when there is a negative VCE.展开更多
BACKGROUND Clinically significant portal hypertension(CSPH)is a crucial prognostic deter-minant for liver-related events(LREs)in patients with compensated viral cir-rhosis.Liver stiffness measurement(LSM)-related mark...BACKGROUND Clinically significant portal hypertension(CSPH)is a crucial prognostic deter-minant for liver-related events(LREs)in patients with compensated viral cir-rhosis.Liver stiffness measurement(LSM)-related markers may help to predict the risk of LREs.AIM To evaluate the value of LSM and its composite biomarkers[LSM-platelet ratio(LPR),LSM-albumin ratio(LAR)]in predicting LREs.METHODS This study retrospectively enrolled compensated viral cirrhosis patients with CSPH.The Cox regression model was employed to examine the prediction of LSM,LPR,and LAR for LREs.The model performance was assessed through receiver operating characteristic,decision curve,and time-dependent area under the curve analysis.The Kaplan-Meier curve was used to evaluate the cumulative incidence of LREs,and further stratified analysis of different LREs was per-formed.RESULTS A total of 598 patients were included,and 319 patients(53.3%)developed LREs during follow-up.Multivariate proportional hazards modeling demonstrated that LSM,LPR,and LAR were independent predictors of LREs.LPR had better performance in predicting LREs than LAR and LSM(area under the curve=0.780,0.727,0.683,respectively,all P<0.05).The cumulative incidence of LREs in the high-risk group were significantly higher than that in the low-risk group(P<0.001).Among the different LREs,LPR was superior to LSM and LAR in predicting liver decompensation,while the difference in predicting hepatocellular carcinoma and liver-related death was relatively small.CONCLUSION LPR is superior to LSM and LAR in predicting LREs in compensated viral cirrhosis patients with CSPH,especially in predicting liver decompensation.展开更多
Liver biopsy is rarely performed for the diagnosis of compensated advanced chronic liver disease(cACLD)in the current clinical hepatology practice.In the early stage,cACLD presents without portal hypertension,and in t...Liver biopsy is rarely performed for the diagnosis of compensated advanced chronic liver disease(cACLD)in the current clinical hepatology practice.In the early stage,cACLD presents without portal hypertension,and in the later stage,it presents with portal hypertension.Hepatic venous pressure gradient measu-rement is the gold standard for diagnosing portal hypertension,but it is rarely used due to its invasive nature.The recent Baveno VII consensus recommends a noninvasive strategy for the diagnosis of cACLD and clinically significant portal hypertension(CSPH).However,there is some uncertainty regarding the dia-gnostic accuracy of Baveno VII criteria for predicting CSPH among patients with metabolic dysfunction-associated steatotic liver disease(MASLD).This is per-tinent as MASLD has become the most important cause of cACLD in the United States.This mini-review outlines the diagnostic performance of Baveno VII cri-teria and other noninvasive criteria for predicting CSPH in patients with cACLD from MASLD compared to non-MASLD causes.展开更多
An identification method using Allan variance and equivalent theorem is proposed to identify non-stationary sensor errors mixed out of different simple noises. This method firstly derives the discrete Allan variances ...An identification method using Allan variance and equivalent theorem is proposed to identify non-stationary sensor errors mixed out of different simple noises. This method firstly derives the discrete Allan variances of all component noises inherent in noise sources in terms of their different equations; then the variances are used to estimate the parameters of all component noise models; finally, the original errors are represented by the sum of the non-stationary component noise model and the equivalent m...展开更多
[ Objective] The aim was to study variance type of capsule morphological characters in Platycodon grandiflorum population, and provide some theoretical basis for seeking to genetic markers which can differentiate diff...[ Objective] The aim was to study variance type of capsule morphological characters in Platycodon grandiflorum population, and provide some theoretical basis for seeking to genetic markers which can differentiate different P. grandiflorum and breeding new varieties. [ Method] According to shape morphological characters of capsule from the same population of perennial purple P. gandiflorum, seven types of distinct di- versity capsule were selected, variance analysis and multiple comparison on the length, diameter, length/diameter of the different types of capsule were carried out. [ Result] There is unicolor and bicolor, even trichrome, among main color was brown and purple. Capsule shape was main cone, furthermore, containing long roller type, spheroidicity and sphericity. [ Conclusion] P. gandiflorum capsule was divided into long form, short form and middle type from length/diameter size in perennial culture P. gandiflorum population.展开更多
背景:炎症是脑卒中病理生理过程的关键组成部分,然而脑卒中与炎症之间的因果关系仍不清楚。目的:采用孟德尔随机化及分子对接技术探索91种靶向炎症细胞因子的脑卒中治疗机制。方法:从开放全基因组关联研究数据库(IEU Open GWAS,https://...背景:炎症是脑卒中病理生理过程的关键组成部分,然而脑卒中与炎症之间的因果关系仍不清楚。目的:采用孟德尔随机化及分子对接技术探索91种靶向炎症细胞因子的脑卒中治疗机制。方法:从开放全基因组关联研究数据库(IEU Open GWAS,https://gwas.mrcieu.ac.uk/,由英国布里斯托大学医学研究委员会综合流行病学单位主办)中获得炎症细胞因子及脑卒中的数据,使用逆方差加权法作为主要研究方法进行两样本孟德尔随机化分析,评估91种炎症细胞因子与脑卒中之间的因果关系。随后基于孟德尔随机化研究结果进行了基因本体分析和京都基因与基因组通路分析,并构建了蛋白质-蛋白质相互作用网络。使用美国西奈山伊坎医学院建立的Enrichr数据库(http://amp.pharm.mssm.edu/Enrichr)和美国科罗拉多大学丹佛分校建立的药物特征数据库(http://tanlab.ucdenver.edu/dsigdb)进行脑卒中治疗药物预测,并使用AutoDock软件进行分子对接,通过Discovery Studio2019对结果进行可视化。结果与结论:(1)发现11种炎症细胞因子与全因脑卒中风险之间存在显著的因果关联;9种炎症细胞因子与缺血性脑卒中风险呈强相关;6种细胞因子与大动脉脑卒中风险显著相关;7种炎症细胞因子与心源性栓塞性脑卒中风险呈显著因果关系;12种细胞因子与小血管脑卒中风险显著相关;3种炎症细胞因子与脑内出血风险具有显著的因果关联;(2)基因本体分析和京都基因与基因组通路分析揭示,炎症细胞因子在代谢、炎症及免疫反应等方面对脑卒中具有重要影响;(3)通过蛋白质-蛋白质相互作用网络分析,筛选出与脑卒中密切相关的10种炎症细胞因子;(4)药物预测和分子对接结果表明,阿托伐他汀和氟氢可的松与关键核心靶点白细胞介素18和CCL3的结合力较高;(5)此次研究的数据来源于国际数据库中的欧洲人群,所获得的结果可为中国脑卒中的遗传流行病学研究提供参考;(6)此次研究阐明了炎症细胞因子与脑卒中之间的因果关系,揭示了炎症细胞因子治疗脑卒中的机制,为脑卒中的治疗提供了新思路。展开更多
背景:近期研究表明,肠道菌群可能会影响肌萎缩侧索硬化症的发展进程,然而两者之间的因果关系尚不清楚。目的:利用孟德尔随机化方法探索肠道菌群与肌萎缩侧索硬化症之间的因果关系。方法:从IEU Open GWAS数据库(由英国布里斯托尔大学的...背景:近期研究表明,肠道菌群可能会影响肌萎缩侧索硬化症的发展进程,然而两者之间的因果关系尚不清楚。目的:利用孟德尔随机化方法探索肠道菌群与肌萎缩侧索硬化症之间的因果关系。方法:从IEU Open GWAS数据库(由英国布里斯托尔大学的英国医学研究委员会和遗传流行病学研究所开发,旨在提供与多种疾病相关的全基因组关联研究数据,为开放数据库)中分别获取肠道菌群和肌萎缩侧索硬化症的GWAS数据,以肠道菌群为暴露因素、肌萎缩侧索硬化症为结局变量,使用逆方差加权法、MR-Egger回归法、加权中位数法、加权模型法和简单模型法来探究两者之间的因果关系。使用敏感性分析检验孟德尔随机化结果的可靠性,使用反向孟德尔随机化分析进一步验证两者间的因果关系。结果与结论:(1)正向孟德尔随机化分析结果表明,6种肠道菌群与肌萎缩侧索硬化症之间存在因果关系,其中嗜胆菌属(β=0.206,OR=1.229)、毛螺菌属(β=0.288,OR=1.333)、马文-布莱恩特氏菌属(β=0.196,OR=1.216)、瘤胃球菌UCG010属(β=0.254,OR=1.289)和泰泽氏菌属3型(β=0.128,OR=1.136)可能是肌萎缩侧索硬化症的潜在危险因素,肠杆菌属(β=-0.203,OR=0.816)可能是肌萎缩侧索硬化症的保护因素;(2)在敏感性分析中,未发现显著的异质性和水平多效性(P均> 0.05),反向孟德尔随机化分析亦未揭示肠道菌群与肌萎缩侧索硬化症之间存在反向因果关系;(3)该研究结果不仅为肌萎缩侧索硬化症治疗提供了潜在的生物标志物,还为开发基于肠道菌群的新的干预治疗方案提供了理论依据,对中国基础医学研究具有一定的启示意义。展开更多
文摘In this short review paper, the significant and profound impacts of the Chou’s “invariance theorem” have been briefly presented with crystal clear convincingness.
文摘The prediction of the fracture plane orientation in fatigue is a scientific topic and remains relevant for every type of material. However, in this work, we compared the orientation of the fracture plane obtained experimentally through tests on specimens under multiaxial loading with that calculated by the variance method. In the statistical approach criteria, several methods have been developed but we have presented only one method, namely the variance method using the equivalent stress. She assumes that the fracture plane orientation is the one on which the variance of the equivalent stress is maximum. Three types of equivalent stress are defined for this method [1]: normal stress, shear stress and combined normal and shear stress. The results obtained were compared with experimental results for multiaxial cyclic stress states, and it emerges that the variance method for the case of combined loading is conservative as it gives a better prediction of the fracture plane.
文摘Working toward an efficient duration and timeline for the preconstruction phase should be one of the main objectives for project owners.Failing to plan for and coordinate preconstruction decisions in order to control preconstruction duration and manage time variances can lead to financial insecurities,incomplete contract documents,permitting issues,and unrealistic schedules and resource allocation during this phase.To minimize time variances and ensure a productive decision-making process,project owners should be familiar with critical elements in a project that cause variances in the preconstruction phase timeline.In this study,the impacts of eleven critical preconstruction elements on time variances were analyzed.These eleven preconstruction elements are considered critical in how they impact time variances during the preconstruction phase.They were determined to be critical based either on significantly impacting time variance during the preconstruction phase or believed to be critical from findings from previous studies,however,the findings from this study showed no significant impact on the time variances.In most previous studies focusing on the elements impacting project schedules,data were collected by surveying construction professionals.In this study,objective and quantitative data related to project preconstruction elements were used as opposed to self-reported data.Using the results of this study,project owners and stakeholders will be able to evaluate the critical preconstruction elements impacting the timing of their projects and prioritize decisions related to the critical elements early on during the preconstruction phase.
基金supported by the Ministry of Education,Singapore,under its Academic Research Fund Tier 2 Grant MOE-T2EP20222-0003.
文摘The valuation of financial derivatives often assumes risk neutrality with respect to the risk-neutral martingale measure,which prevents arbitrage opportunities.However,casual traders may still incur substantial losses when trading at this risk-neutral price,especially when the price has to be paid now and the payoff is only realized in the future.This study proposes a new valuation framework that provides risksensitive investors with an additional safeguard.The proposed framework embraces a worst-case perspective while exploiting the underlier’s stochastic process,representing a combination of robust optimization and stochastic programming.Notably,it aims to mitigate losses in the likelier scenarios of the underlying asset’s prices.When the underlier’s returns are independent and lognormally but not necessarily identically distributed,our approach for pricing variance and volatility swaps could be greatly simplified,benefit from parallel computing,and be solved by a two-dimensional grid search.We further derive a closed-form solution in some special stationary cases and provide experimental results to highlight the effect of risk aversion on fending off sizable trading losses.
基金The National Natural Science Foundation of China under contract No.41821004the Basic Scientific Fund for National Public Research Institutes of China under contract No.2020Q08the Fund of Laoshan Laboratory under contract No.LSKJ202201600.
文摘Significant wave period is an important parameter in coastal and offshore engineering design.Traditional spectral wave models do not directly calculate this parameter,which means that it needs to be estimated from the spectral periods using empirical formulas.The wave energy period is one of the wave periods directly output by many wave models and is often used in studies of wave energy.This study investigated the relationship between significant wave period and wave energy period using wave data measured at three stations in the coastal waters of China.The observations recorded at these stations in the South China Sea,the East China Sea,and the Bohai Sea covered a wide range of surface wave conditions.Analysis indicated that the ratio of significant wave period to wave energy period is closely related to the Goda peakedness parameter of the wave spectra.Therefore,we proposed an empirical formula in which significant wave period is a function of wave energy period and the Goda peakedness parameter.Evaluation results showed that the performance of this formula is substantially better than that of fitting formulas that use constant coefficients.
基金supported by the National Natural Science Foundation of China(No.42174011)。
文摘In the variance component estimation(VCE)of geodetic data,the problem of negative VCE is likely to occur.In the ordinary additive error model,there have been related studies to solve the problem of negative variance components.However,there is still no related research in the mixed additive and multiplicative random error model(MAMREM).Based on the MAMREM,this paper applies the nonnegative least squares variance component estimation(NNLS-VCE)algorithm to this model.The correlation formula and iterative algorithm of NNLS-VCE for MAMREM are derived.The problem of negative variance in VCE for MAMREM is solved.This paper uses the digital simulation example and the Digital Terrain Mode(DTM)to prove the proposed algorithm's validity.The experimental results demonstrated that the proposed algorithm can effectively correct the VCE in MAMREM when there is a negative VCE.
基金Supported by the High-Level Chinese Medicine Key Discipline Construction Project,No.zyyzdxk-2023005Capital’s Funds for Health Improvement and Research,No.2024-1-2173+2 种基金National Natural Science Foundation of China,No.82474419 and No.82474426Beijing Municipal Natural Science Foundation,No.7232272Beijing Traditional Chinese Medicine Technology Development Fund Project,No.BJZYZD-2023-12.
文摘BACKGROUND Clinically significant portal hypertension(CSPH)is a crucial prognostic deter-minant for liver-related events(LREs)in patients with compensated viral cir-rhosis.Liver stiffness measurement(LSM)-related markers may help to predict the risk of LREs.AIM To evaluate the value of LSM and its composite biomarkers[LSM-platelet ratio(LPR),LSM-albumin ratio(LAR)]in predicting LREs.METHODS This study retrospectively enrolled compensated viral cirrhosis patients with CSPH.The Cox regression model was employed to examine the prediction of LSM,LPR,and LAR for LREs.The model performance was assessed through receiver operating characteristic,decision curve,and time-dependent area under the curve analysis.The Kaplan-Meier curve was used to evaluate the cumulative incidence of LREs,and further stratified analysis of different LREs was per-formed.RESULTS A total of 598 patients were included,and 319 patients(53.3%)developed LREs during follow-up.Multivariate proportional hazards modeling demonstrated that LSM,LPR,and LAR were independent predictors of LREs.LPR had better performance in predicting LREs than LAR and LSM(area under the curve=0.780,0.727,0.683,respectively,all P<0.05).The cumulative incidence of LREs in the high-risk group were significantly higher than that in the low-risk group(P<0.001).Among the different LREs,LPR was superior to LSM and LAR in predicting liver decompensation,while the difference in predicting hepatocellular carcinoma and liver-related death was relatively small.CONCLUSION LPR is superior to LSM and LAR in predicting LREs in compensated viral cirrhosis patients with CSPH,especially in predicting liver decompensation.
文摘Liver biopsy is rarely performed for the diagnosis of compensated advanced chronic liver disease(cACLD)in the current clinical hepatology practice.In the early stage,cACLD presents without portal hypertension,and in the later stage,it presents with portal hypertension.Hepatic venous pressure gradient measu-rement is the gold standard for diagnosing portal hypertension,but it is rarely used due to its invasive nature.The recent Baveno VII consensus recommends a noninvasive strategy for the diagnosis of cACLD and clinically significant portal hypertension(CSPH).However,there is some uncertainty regarding the dia-gnostic accuracy of Baveno VII criteria for predicting CSPH among patients with metabolic dysfunction-associated steatotic liver disease(MASLD).This is per-tinent as MASLD has become the most important cause of cACLD in the United States.This mini-review outlines the diagnostic performance of Baveno VII cri-teria and other noninvasive criteria for predicting CSPH in patients with cACLD from MASLD compared to non-MASLD causes.
基金National Basic Research Program of China (JW132006093)
文摘An identification method using Allan variance and equivalent theorem is proposed to identify non-stationary sensor errors mixed out of different simple noises. This method firstly derives the discrete Allan variances of all component noises inherent in noise sources in terms of their different equations; then the variances are used to estimate the parameters of all component noise models; finally, the original errors are represented by the sum of the non-stationary component noise model and the equivalent m...
文摘[ Objective] The aim was to study variance type of capsule morphological characters in Platycodon grandiflorum population, and provide some theoretical basis for seeking to genetic markers which can differentiate different P. grandiflorum and breeding new varieties. [ Method] According to shape morphological characters of capsule from the same population of perennial purple P. gandiflorum, seven types of distinct di- versity capsule were selected, variance analysis and multiple comparison on the length, diameter, length/diameter of the different types of capsule were carried out. [ Result] There is unicolor and bicolor, even trichrome, among main color was brown and purple. Capsule shape was main cone, furthermore, containing long roller type, spheroidicity and sphericity. [ Conclusion] P. gandiflorum capsule was divided into long form, short form and middle type from length/diameter size in perennial culture P. gandiflorum population.
文摘背景:炎症是脑卒中病理生理过程的关键组成部分,然而脑卒中与炎症之间的因果关系仍不清楚。目的:采用孟德尔随机化及分子对接技术探索91种靶向炎症细胞因子的脑卒中治疗机制。方法:从开放全基因组关联研究数据库(IEU Open GWAS,https://gwas.mrcieu.ac.uk/,由英国布里斯托大学医学研究委员会综合流行病学单位主办)中获得炎症细胞因子及脑卒中的数据,使用逆方差加权法作为主要研究方法进行两样本孟德尔随机化分析,评估91种炎症细胞因子与脑卒中之间的因果关系。随后基于孟德尔随机化研究结果进行了基因本体分析和京都基因与基因组通路分析,并构建了蛋白质-蛋白质相互作用网络。使用美国西奈山伊坎医学院建立的Enrichr数据库(http://amp.pharm.mssm.edu/Enrichr)和美国科罗拉多大学丹佛分校建立的药物特征数据库(http://tanlab.ucdenver.edu/dsigdb)进行脑卒中治疗药物预测,并使用AutoDock软件进行分子对接,通过Discovery Studio2019对结果进行可视化。结果与结论:(1)发现11种炎症细胞因子与全因脑卒中风险之间存在显著的因果关联;9种炎症细胞因子与缺血性脑卒中风险呈强相关;6种细胞因子与大动脉脑卒中风险显著相关;7种炎症细胞因子与心源性栓塞性脑卒中风险呈显著因果关系;12种细胞因子与小血管脑卒中风险显著相关;3种炎症细胞因子与脑内出血风险具有显著的因果关联;(2)基因本体分析和京都基因与基因组通路分析揭示,炎症细胞因子在代谢、炎症及免疫反应等方面对脑卒中具有重要影响;(3)通过蛋白质-蛋白质相互作用网络分析,筛选出与脑卒中密切相关的10种炎症细胞因子;(4)药物预测和分子对接结果表明,阿托伐他汀和氟氢可的松与关键核心靶点白细胞介素18和CCL3的结合力较高;(5)此次研究的数据来源于国际数据库中的欧洲人群,所获得的结果可为中国脑卒中的遗传流行病学研究提供参考;(6)此次研究阐明了炎症细胞因子与脑卒中之间的因果关系,揭示了炎症细胞因子治疗脑卒中的机制,为脑卒中的治疗提供了新思路。
文摘背景:近期研究表明,肠道菌群可能会影响肌萎缩侧索硬化症的发展进程,然而两者之间的因果关系尚不清楚。目的:利用孟德尔随机化方法探索肠道菌群与肌萎缩侧索硬化症之间的因果关系。方法:从IEU Open GWAS数据库(由英国布里斯托尔大学的英国医学研究委员会和遗传流行病学研究所开发,旨在提供与多种疾病相关的全基因组关联研究数据,为开放数据库)中分别获取肠道菌群和肌萎缩侧索硬化症的GWAS数据,以肠道菌群为暴露因素、肌萎缩侧索硬化症为结局变量,使用逆方差加权法、MR-Egger回归法、加权中位数法、加权模型法和简单模型法来探究两者之间的因果关系。使用敏感性分析检验孟德尔随机化结果的可靠性,使用反向孟德尔随机化分析进一步验证两者间的因果关系。结果与结论:(1)正向孟德尔随机化分析结果表明,6种肠道菌群与肌萎缩侧索硬化症之间存在因果关系,其中嗜胆菌属(β=0.206,OR=1.229)、毛螺菌属(β=0.288,OR=1.333)、马文-布莱恩特氏菌属(β=0.196,OR=1.216)、瘤胃球菌UCG010属(β=0.254,OR=1.289)和泰泽氏菌属3型(β=0.128,OR=1.136)可能是肌萎缩侧索硬化症的潜在危险因素,肠杆菌属(β=-0.203,OR=0.816)可能是肌萎缩侧索硬化症的保护因素;(2)在敏感性分析中,未发现显著的异质性和水平多效性(P均> 0.05),反向孟德尔随机化分析亦未揭示肠道菌群与肌萎缩侧索硬化症之间存在反向因果关系;(3)该研究结果不仅为肌萎缩侧索硬化症治疗提供了潜在的生物标志物,还为开发基于肠道菌群的新的干预治疗方案提供了理论依据,对中国基础医学研究具有一定的启示意义。
