<span style="font-family:Verdana;">The effects of each of the flavonoids;genistein (G), quercetin (Q) and</span><span style="font-family:""><span style="font-family:V...<span style="font-family:Verdana;">The effects of each of the flavonoids;genistein (G), quercetin (Q) and</span><span style="font-family:""><span style="font-family:Verdana;"> kaempferol (K) at several doses on lipid peroxides (LP) and reduced glutathione (GSH) in pooled human liver microsomes (HLMs) were investigated following the oxidative damage for 4, 6, 18 and 24 hr. HLMs (1 mg/ml) were exposed to each of the above flavonoids at 0, 5, 10, 15, 20 or 25 μM and incubated for the respective times as previously stated. Our hypothesis was that HLMs exposed to the flavonoids for the respective exposure times can decrease LP and increase GSH in HLMs to better cope with the oxidative stress. </span><span style="font-family:Verdana;">The results of our studies indicate that each of the flavonoids significantly (p < 0.01) decreased LP compared to their respective controls. The highest decrease in LP was observed for K followed by Q and G. Significant increases (p < 0.01) in GSH were observed for the flavonoid doses tested with the highest</span><span style="font-family:Verdana;"> levels observed for Q for the 24-hr. incubation. The findings suggest that the flavonoids modulate oxidative stress in HLMs by decreasing LP and such decreases in LPs may be due to the increasing and or the replenished levels of GSH in the said cells to better cope with the oxidative stress.</span></span>展开更多
[目的]现有的作物估产模型通常在灾害气候条件下的估产精度不高,本研究提出一种基于干旱天气指数减产率模型的改进分层线性模型(Improved Hierarchical Linear Model,IHLM),旨在提高在干旱条件下作物产量估算的精度。[方法]采用最大值...[目的]现有的作物估产模型通常在灾害气候条件下的估产精度不高,本研究提出一种基于干旱天气指数减产率模型的改进分层线性模型(Improved Hierarchical Linear Model,IHLM),旨在提高在干旱条件下作物产量估算的精度。[方法]采用最大值的增强植被指数-2(Maximum Enhanced Vegetation Index 2,EVI2max)和每年3月~5月降水量,辐射量和气温等气象数据和2018—2021年山东省160个农情调查基点的冬小麦实测产量数据构建冬小麦产量预测基础分层线性模型(Hierarchical Linear Model,HLM)。考虑到气象因素的变异程度是影响作物生长的关键障碍因子,首先将气象因子相对性计算进行模型改进,并对改进的HLM模型与随机森林(Random Forest,RF)模型、支持向量回归(Support Vector Regression,SVR)模型和极端梯度提升(Extreme Gradient Boosting,XGBOOST)模型进行精度对比。然后引入农业保险行业的干旱天气指数减产率模型,对改进的HLM模型进一步优化,从而更加适应干旱条件下的作物估产。为了验证IHLM模型的迁移性,本研究将其应用于河南省进行对比分析,以评估该模型在不同地理和气候条件下的表现。[结果和讨论]基于相对气象因子(Relative Meteorological Factors,rMF)改进的HLM模型精度相比于RF、SVR和XGBOOST更高,验证精度皮尔逊相关系数r为0.76,均方根误差(Root Mean Square Error,RMSE)为0.60 t/hm^(2),归一化均方根误差(Normalized Root Mean Square Error,nRMSE)为11.21%。在干旱条件数据集中,利用冬小麦干旱天气指数和冬小麦减产率的关系对模型进行了改进,改进之后RMSE减少了0.48 t/hm^(2),nRMSE减少了28.64个百分点,提高了IHLM模型在干旱条件下的精度。[结论]该研究对冬小麦产量HLM模型进行改进,提高了模型精度,在干旱情况下模型精度和稳定性有一定提升,相比于RF、SVR、XGBOOST模型,IHLM模型更适合对冬小麦产量预测。展开更多
随着人口老龄化进程的加速,老年健康成为学界关注的一大领域。探究老年健康不平等及其影响机理,准确理解老年人健康指标的变化趋势,对于实现健康老龄化的目标具有积极的意义。本文采用中国健康与养老追踪调查(China Health and Retireme...随着人口老龄化进程的加速,老年健康成为学界关注的一大领域。探究老年健康不平等及其影响机理,准确理解老年人健康指标的变化趋势,对于实现健康老龄化的目标具有积极的意义。本文采用中国健康与养老追踪调查(China Health and Retirement Longitudinal Study,CHARLS)数据,运用分层线性模型考察老年人健康水平的影响因素和群际差异。本文还利用SF-36量表,基于主成分分析方法构建涵盖主客观健康指标,在地区和社区层面重点探究教育程度、个人收入等因素对于健康不平等的影响机理。分析结果显示,个人和家庭的社会经济条件对于老年健康有积极的作用,物质资源越丰富的老人越健康;地区层面,经济发展给健康带来了正向的外部性,经济越发达老年人健康指数越高;社区层面,老年人生活的社区经济水平越高,其健康水平分化越严重。从受教育水平来看,老年健康体现为社区层面"低度平均,高度不均",个体层面"低度不均,高度平均",收入水平在个体层面和社区层面产生了相反的影响。展开更多
文摘<span style="font-family:Verdana;">The effects of each of the flavonoids;genistein (G), quercetin (Q) and</span><span style="font-family:""><span style="font-family:Verdana;"> kaempferol (K) at several doses on lipid peroxides (LP) and reduced glutathione (GSH) in pooled human liver microsomes (HLMs) were investigated following the oxidative damage for 4, 6, 18 and 24 hr. HLMs (1 mg/ml) were exposed to each of the above flavonoids at 0, 5, 10, 15, 20 or 25 μM and incubated for the respective times as previously stated. Our hypothesis was that HLMs exposed to the flavonoids for the respective exposure times can decrease LP and increase GSH in HLMs to better cope with the oxidative stress. </span><span style="font-family:Verdana;">The results of our studies indicate that each of the flavonoids significantly (p < 0.01) decreased LP compared to their respective controls. The highest decrease in LP was observed for K followed by Q and G. Significant increases (p < 0.01) in GSH were observed for the flavonoid doses tested with the highest</span><span style="font-family:Verdana;"> levels observed for Q for the 24-hr. incubation. The findings suggest that the flavonoids modulate oxidative stress in HLMs by decreasing LP and such decreases in LPs may be due to the increasing and or the replenished levels of GSH in the said cells to better cope with the oxidative stress.</span></span>
文摘随着人口老龄化进程的加速,老年健康成为学界关注的一大领域。探究老年健康不平等及其影响机理,准确理解老年人健康指标的变化趋势,对于实现健康老龄化的目标具有积极的意义。本文采用中国健康与养老追踪调查(China Health and Retirement Longitudinal Study,CHARLS)数据,运用分层线性模型考察老年人健康水平的影响因素和群际差异。本文还利用SF-36量表,基于主成分分析方法构建涵盖主客观健康指标,在地区和社区层面重点探究教育程度、个人收入等因素对于健康不平等的影响机理。分析结果显示,个人和家庭的社会经济条件对于老年健康有积极的作用,物质资源越丰富的老人越健康;地区层面,经济发展给健康带来了正向的外部性,经济越发达老年人健康指数越高;社区层面,老年人生活的社区经济水平越高,其健康水平分化越严重。从受教育水平来看,老年健康体现为社区层面"低度平均,高度不均",个体层面"低度不均,高度平均",收入水平在个体层面和社区层面产生了相反的影响。
