Helicobacter pylori is the microbial agent most responsible for gastro-duodenal ulcer and chronic gastritis, which can develop into carcinoma of the stomach. This study was performed in Wad Medani Teaching Hospital, S...Helicobacter pylori is the microbial agent most responsible for gastro-duodenal ulcer and chronic gastritis, which can develop into carcinoma of the stomach. This study was performed in Wad Medani Teaching Hospital, Sudan to detect Helicobacter pylori in stomach samples, and evaluate the performance of the tests used, which were histological stains and PCR. Gastric biopsies were obtained from 105 referred patients during endoscopy, and fixed specimens examined by haematoxylin-eosin and Warthin-Starry silver stains, while DNA was extracted for glmM gene amplification. Epigastric pain was the most common symptom at 78% (82/105) and chronic gastritis recorded with 71% (68/105) of endoscopy results. Warthin-Starry silver stain gave 31% (33/105) as positive for Helicobacter pylori followed by glmM gene 27% (28/105) and haematoxylin-eosin 24% (25/105). The study indicated good performance of histological staining and high specificity of glmM gene in detection of Helicobacter pylori from gastric biopsies.展开更多
本文首次提出使用广义线性混合模型(generalized linear mixed model,GLMM)对概化理论(GT)和项目反应理论(IRT)进行统合,即在一次统计中就能同时获得GT和IRT所需要的估计结果。模拟研究结果显示:相比于传统的GT方差分量估计方法——期...本文首次提出使用广义线性混合模型(generalized linear mixed model,GLMM)对概化理论(GT)和项目反应理论(IRT)进行统合,即在一次统计中就能同时获得GT和IRT所需要的估计结果。模拟研究结果显示:相比于传统的GT方差分量估计方法——期望均值平方(expected mean squares,EMS),GLMM可以获得更准确的方差分量、概化系数(G系数)和可靠性系数(Φ系数)估计值;相对于传统Rasch模型,GLMM可以获得更准确的题目难度参数估计值。实证研究展示GLMM在实际心理测量数据分析中的应用。展开更多
Generalized linear mixed models(GLMMs)have been widely used in contemporary ecology studies.However,determination of the relative importance of collinear predictors(i.e.fixed effects)to response variables is one of th...Generalized linear mixed models(GLMMs)have been widely used in contemporary ecology studies.However,determination of the relative importance of collinear predictors(i.e.fixed effects)to response variables is one of the challenges in GLMMs.Here,we developed a novel R package,glmm.hp,to decompose marginal R2^(2)explained by fixed effects in GLMMs.The algorithm of glmm.hp is based on the recently proposed approach‘average shared variance’i.e.used for multivariate analysis.We explained the principle and demonstrated the use of this package by simulated dataset.The output of glmm.hp shows individual marginal R2^(2)s that can be used to evaluate the relative importance of predictors,which sums up to the overall marginal R2^(2).Overall,we believe the glmm.hp package will be helpful in the interpretation of GLMM outcomes.展开更多
多环芳烃作为环境污染物中一类极为重要的物质,探索它的去除方法吸引了全球环境学者及政府的高度重视。大气氮沉降在过去几十年不断增加,已影响到陆地生态系统氮循环过程。但目前,氮沉降与多环芳烃降解之间的关系尚不明确。通过在新疆...多环芳烃作为环境污染物中一类极为重要的物质,探索它的去除方法吸引了全球环境学者及政府的高度重视。大气氮沉降在过去几十年不断增加,已影响到陆地生态系统氮循环过程。但目前,氮沉降与多环芳烃降解之间的关系尚不明确。通过在新疆克拉玛依市石油化工厂附近的荒漠草地上,模拟氮沉降实验,通过在4氮添加梯度(CK=0;N1=10;N2=30;N3=90 kg N hm-2 a-1)上调查土壤中16种优先控制多环芳烃的含量和总量(∑PAHs),以及它们与生物非生物环境因子(土壤环境因子、土壤酶活性和土壤微生物功能多样性)之间的关系,旨在揭示氮沉降对多环芳烃降解的影响。结果表明:除苊烯(Acenaphthylene)和苊(Acenaphthene)两种多环芳烃在4个N添加梯度上未检测到含量外,∑PAHs和其他14种优先控制多环芳烃在土壤中的含量均随氮添加量增加显著减小(N2≤N3<N1<CK)(P<0.01);对照样地(CK)在施氮前后,低高分子多环芳烃含量的比值>1.00,且0.40<荧蒽(Fluoranthene)/[(荧蒽(Fluoranthene)+芘(Pyrene)]<0.50,石油污染物是当地土壤中多环芳烃的主要来源;9月份克拉玛依市荒漠草地土壤中∑PAHs约(28.91±2.32) mg/kg,属于多环芳烃重污染土壤;广义线性混合效应模型结果显示,在大多数情况下,∑PAHs和14种多环芳烃的含量与土壤有机质、铵态氮、硝态氮、总氮、有效磷和脲酶活性显著相关(P<0.05),但其与生物非生物环境因子之间的回归关系在不同种类多环芳烃之间差异较大。综上可知,土壤中多环芳烃的降解是一个非常复杂的过程,它是自身属性、植物根系和土壤微生物等多重因子相互共同作用的结果。在干旱区荒漠草地中,氮添加能提升土壤中营养物质的可利用性、植物根系和土壤微生物的活性,有利于降解土壤多环芳烃。展开更多
Background: Most patients infected with Helicobacter pylori show no clinical symptoms. Nonetheless, approximately 10% to 20% of these patients will develop peptic ulcers and 1% will develop gastric cancer. The Interna...Background: Most patients infected with Helicobacter pylori show no clinical symptoms. Nonetheless, approximately 10% to 20% of these patients will develop peptic ulcers and 1% will develop gastric cancer. The International Agency for Cancer Research has classified Helicobacter pylori as a Group 1 carcinogen. Materials and Methods: Drinking water samples from 20 cantons situated in areas of low and high incidence of gastric cancer in Costa Rica were analyzed. Water samples were concentrated and the nitrocellulose filter was cultivated for later molecular identification of Helicobacter pylori using the glmM marker. The tumor necrosis factor-alpha inducing protein (Tipalpha TNF-α) was used as a pathogenicity marker of the strains found followed by the sequencing of two products. Information on water management by aqueduct operators was collected in order to establish statistical relationships. Results: A total of 112 water samples were analyzed. Successful cultivation and molecular identification using the glmM marker was achieved in 39% of samples from areas of high incidence and in 7.5% of samples from areas of low incidence. Two glmM gene PCR products were sequenced and confirmed as true positives. Conclusions: The highest prevalence rate of Helicobacter pylori was found in water from areas with a high incidence of gastric cancer. Additionally, significant statistical correlations were established among environmental conditions, drinking water management and incidence of gastric cancer.展开更多
文摘Helicobacter pylori is the microbial agent most responsible for gastro-duodenal ulcer and chronic gastritis, which can develop into carcinoma of the stomach. This study was performed in Wad Medani Teaching Hospital, Sudan to detect Helicobacter pylori in stomach samples, and evaluate the performance of the tests used, which were histological stains and PCR. Gastric biopsies were obtained from 105 referred patients during endoscopy, and fixed specimens examined by haematoxylin-eosin and Warthin-Starry silver stains, while DNA was extracted for glmM gene amplification. Epigastric pain was the most common symptom at 78% (82/105) and chronic gastritis recorded with 71% (68/105) of endoscopy results. Warthin-Starry silver stain gave 31% (33/105) as positive for Helicobacter pylori followed by glmM gene 27% (28/105) and haematoxylin-eosin 24% (25/105). The study indicated good performance of histological staining and high specificity of glmM gene in detection of Helicobacter pylori from gastric biopsies.
文摘本文首次提出使用广义线性混合模型(generalized linear mixed model,GLMM)对概化理论(GT)和项目反应理论(IRT)进行统合,即在一次统计中就能同时获得GT和IRT所需要的估计结果。模拟研究结果显示:相比于传统的GT方差分量估计方法——期望均值平方(expected mean squares,EMS),GLMM可以获得更准确的方差分量、概化系数(G系数)和可靠性系数(Φ系数)估计值;相对于传统Rasch模型,GLMM可以获得更准确的题目难度参数估计值。实证研究展示GLMM在实际心理测量数据分析中的应用。
基金This work was supported by the National Natural Science Foundation of China(32271551)the Metasequoia funding of Nanjing Forestry University.Conflict of interest statement.The authors declare that they have no conflict of interest.
文摘Generalized linear mixed models(GLMMs)have been widely used in contemporary ecology studies.However,determination of the relative importance of collinear predictors(i.e.fixed effects)to response variables is one of the challenges in GLMMs.Here,we developed a novel R package,glmm.hp,to decompose marginal R2^(2)explained by fixed effects in GLMMs.The algorithm of glmm.hp is based on the recently proposed approach‘average shared variance’i.e.used for multivariate analysis.We explained the principle and demonstrated the use of this package by simulated dataset.The output of glmm.hp shows individual marginal R2^(2)s that can be used to evaluate the relative importance of predictors,which sums up to the overall marginal R2^(2).Overall,we believe the glmm.hp package will be helpful in the interpretation of GLMM outcomes.
文摘多环芳烃作为环境污染物中一类极为重要的物质,探索它的去除方法吸引了全球环境学者及政府的高度重视。大气氮沉降在过去几十年不断增加,已影响到陆地生态系统氮循环过程。但目前,氮沉降与多环芳烃降解之间的关系尚不明确。通过在新疆克拉玛依市石油化工厂附近的荒漠草地上,模拟氮沉降实验,通过在4氮添加梯度(CK=0;N1=10;N2=30;N3=90 kg N hm-2 a-1)上调查土壤中16种优先控制多环芳烃的含量和总量(∑PAHs),以及它们与生物非生物环境因子(土壤环境因子、土壤酶活性和土壤微生物功能多样性)之间的关系,旨在揭示氮沉降对多环芳烃降解的影响。结果表明:除苊烯(Acenaphthylene)和苊(Acenaphthene)两种多环芳烃在4个N添加梯度上未检测到含量外,∑PAHs和其他14种优先控制多环芳烃在土壤中的含量均随氮添加量增加显著减小(N2≤N3<N1<CK)(P<0.01);对照样地(CK)在施氮前后,低高分子多环芳烃含量的比值>1.00,且0.40<荧蒽(Fluoranthene)/[(荧蒽(Fluoranthene)+芘(Pyrene)]<0.50,石油污染物是当地土壤中多环芳烃的主要来源;9月份克拉玛依市荒漠草地土壤中∑PAHs约(28.91±2.32) mg/kg,属于多环芳烃重污染土壤;广义线性混合效应模型结果显示,在大多数情况下,∑PAHs和14种多环芳烃的含量与土壤有机质、铵态氮、硝态氮、总氮、有效磷和脲酶活性显著相关(P<0.05),但其与生物非生物环境因子之间的回归关系在不同种类多环芳烃之间差异较大。综上可知,土壤中多环芳烃的降解是一个非常复杂的过程,它是自身属性、植物根系和土壤微生物等多重因子相互共同作用的结果。在干旱区荒漠草地中,氮添加能提升土壤中营养物质的可利用性、植物根系和土壤微生物的活性,有利于降解土壤多环芳烃。
文摘Background: Most patients infected with Helicobacter pylori show no clinical symptoms. Nonetheless, approximately 10% to 20% of these patients will develop peptic ulcers and 1% will develop gastric cancer. The International Agency for Cancer Research has classified Helicobacter pylori as a Group 1 carcinogen. Materials and Methods: Drinking water samples from 20 cantons situated in areas of low and high incidence of gastric cancer in Costa Rica were analyzed. Water samples were concentrated and the nitrocellulose filter was cultivated for later molecular identification of Helicobacter pylori using the glmM marker. The tumor necrosis factor-alpha inducing protein (Tipalpha TNF-α) was used as a pathogenicity marker of the strains found followed by the sequencing of two products. Information on water management by aqueduct operators was collected in order to establish statistical relationships. Results: A total of 112 water samples were analyzed. Successful cultivation and molecular identification using the glmM marker was achieved in 39% of samples from areas of high incidence and in 7.5% of samples from areas of low incidence. Two glmM gene PCR products were sequenced and confirmed as true positives. Conclusions: The highest prevalence rate of Helicobacter pylori was found in water from areas with a high incidence of gastric cancer. Additionally, significant statistical correlations were established among environmental conditions, drinking water management and incidence of gastric cancer.
