期刊文献+
共找到4篇文章
< 1 >
每页显示 20 50 100
翠柏木材管胞特性及结晶度的径向变异分析 被引量:4
1
作者 廖声熙 杨振寅 +3 位作者 崔凯 孙庆丰 石江涛 刘方炎 《南京林业大学学报(自然科学版)》 CAS CSCD 北大核心 2013年第1期87-90,共4页
对翠柏木材的管胞长度、宽度和及木材的结晶度径向变异进行分析并建立数学模型,结果表明:(1)翠柏木材管胞长度为1 886~3 370μm,宽度为7~23μm,结晶度为30.26%~50.12%,且它们的径向变异规律相似,均是20年前增加显著,于20~25 a趋于稳... 对翠柏木材的管胞长度、宽度和及木材的结晶度径向变异进行分析并建立数学模型,结果表明:(1)翠柏木材管胞长度为1 886~3 370μm,宽度为7~23μm,结晶度为30.26%~50.12%,且它们的径向变异规律相似,均是20年前增加显著,于20~25 a趋于稳定,可将翠柏木材的成熟期界定为20~25 a。(2)翠柏木材结晶度与早材管胞长度、宽度以及晚材管胞长度、宽度间的相关系数分别为0.933、0.955、0.991、0.964,均存在极显著相关,进一步拟合各管胞特征值与结晶度的回归方程,建立的回归模型相关性均达0.95以上。因此,可利用木材结晶度对木材管胞特征进行预测。 展开更多
关键词 翠柏 木材管胞特性 结晶度 径向变异
下载PDF
红心杉管胞特性及年轮与气候因子的关系
2
作者 郑献懂 《农村科学实验》 2021年第31期141-143,共3页
树轮在细胞尺度上的表征是树轮木质部解剖特征,对于树轮的宽度变化能从微观角度解释。本文以融水苗族自治县的红心杉为研究对象,首先介绍红心杉的管胞特性,其次分析管胞性状与生长轮之间的关系,最后研究管胞性状对气候的响应。红心杉管... 树轮在细胞尺度上的表征是树轮木质部解剖特征,对于树轮的宽度变化能从微观角度解释。本文以融水苗族自治县的红心杉为研究对象,首先介绍红心杉的管胞特性,其次分析管胞性状与生长轮之间的关系,最后研究管胞性状对气候的响应。红心杉管胞特性及年轮与气候因子的关系研究,能为红心杉对培育与种植提供支持,为市场提供高质量的木材来源。 展开更多
关键词 红心杉 管胞特性 管胞年轮 气候因子
下载PDF
Combined hepatocellular and cholangiocellular carcinoma presenting with radiological characteristics of focal nodular hyperplasia 被引量:4
3
作者 Inneke Willekens Anne Hoorens +3 位作者 Caroline Geers Bart Op de Beeck Frederik Vandenbroucke Johan de Mey 《World Journal of Gastroenterology》 SCIE CAS CSCD 2009年第31期3940-3943,共4页
Combined hepatocellular and cholangiocellular carcinoma (cHCC-CC) is a rare tumor type containing unequivocal elements of both hepatocellular carcinoma and cholangiocarcinoma that are intimately mixed. Although these ... Combined hepatocellular and cholangiocellular carcinoma (cHCC-CC) is a rare tumor type containing unequivocal elements of both hepatocellular carcinoma and cholangiocarcinoma that are intimately mixed. Although these tumors are usually considered to be more related to hepatocellular carcinoma than to cholangiocarcinoma, they sometimes, in contrast to hepatocellular carcinoma, contain a significant amount of fibrous stroma. This might in some cases explain atypical radiological features. We report a case of a cHCC-CC in a 47-year-old female that resembled focal nodular hyperplasia on Magnetic Resonance Imaging. Correlation of imaging and serum levels of α-fetoprotein and CA19.9 can help to make the correct diagnosis preoperatively. 展开更多
关键词 Combined hepatocellular Cholangiocellular carcinoma Magnetic resonance imaging
下载PDF
Endothelium-specific SIRT1 overexpression inhibits hyperglycemia-induced upregulation of vascular cell senescence 被引量:16
4
作者 CHEN HouZao WAN YanZhen +9 位作者 ZHOU Shuang LU YunBiao ZHANG ZhuQin ZHANG Ran CHEN Feng HAO DeLong ZHAO Xiang GUO ZhiChen LIU DePei LIANG ChihChuan 《Science China(Life Sciences)》 SCIE CAS 2012年第6期467-473,共7页
The rapidly increasing prevalence of diabetes mellitus worldwide is one of the most serious and challenging health problems in the 21st century. Mammalian sirtuin 1 (SIRT1) has been shown to decrease high-glucose-in... The rapidly increasing prevalence of diabetes mellitus worldwide is one of the most serious and challenging health problems in the 21st century. Mammalian sirtuin 1 (SIRT1) has been shown to decrease high-glucose-induced endothelial cell senescence in vitro and prevent hyperglycemia-induced vascular dysfunction. However, a role for SIRTI in prevention of hyperglyce- mia-induced vascular cell senescence in vivo remains unclear. We used endothelium-specific SIRT1 transgenic (SIRT1-Tg) mice and wild-type (WT) mice to construct a 40-week streptozotocin (STZ)-induced diabetic mouse model. In this mode, 42.9% of wild-type (WT) mice and 38.5% of SIRT1-Tg mice were successfully established as diabetic. Forty weeks of hyper- glycemia induced significant vascular cell senescence in aortas of mice, as indicated by upregulation of expression of senes- cence-associated markers including p53, p21 and plasminogen activator inhibitor-1 (PAI-1). However, SIRT1-Tg diabetic mice displayed dramatically decreased expression of p53, p21 and PAI-I compared with diabetic WT mice. Moreover, man- ganese superoxide dismutase expression (MnSOD) was significantly downregulated in the aortas of diabetic WT mice, but was preserved in diabetic SIRT1-Tg mice. Furthermore, expression of the oxidative stress adaptor p66Shc was significantly de- creased in aortas of SIRT1-Tg diabetic mice compared with WT diabetic mice. Overall, these findings suggest that SIRT 1-mediated inhibition of hyperglycemia-induced vascular cell senescence is mediated at least partly through the reduction of oxidative stress. 展开更多
关键词 SIRT1 HYPERGLYCEMIA vascular cell senescence
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部