检索结果-南通市图书馆

Power Dependent of Nonlinear Absorption Coefficient of CdSe-Au Hybrid Nanocomposites

Optics and Photonics Journal 2015年第4期5卷 125-135页

作者： Abeer Salah mona bakr Salah Hassabelnaby Iftitan Azzouz Yehia Badr National Institute of Laser Enhanced Sciences Cairo University Giza Egypt

Power dependent study of optical nonlinear absorption coefficient of semiconductor-plasmonic hybrid nanocomposites of CdSe:Au was investigated using Z-scan technique, provided with nanosecond pulses of second harmonic Nd:YAG laser. The prepared materials were characterized with linear absorption and High Resolution Transmission Electron Microscope (HRTEM) which confirm the quantum confinement of CdSe as well as the formation of CdSe:Au core shell quantum dots. An analysis of power dependence open aperture Z-scan was discussed. A change from saturable absorption (SA) to reverse saturable absorption (RSA) is observed with increasing the laser power. Also, an enhancement of the nonlinear absorption coefficient of CdSe:Au of larger sizes compared to Au nanoparticles was detected.

关键词： Z-Scan Nonlinear Absorption Optical Limiting CdSe:Au

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Urinary Vascular Endothelial Growth Factor (VEGF) as a Novel Marker for Early Prediction of Esophageal Varices in Patients with Chronic Liver Disease

引用

Open Journal of Gastroenterology 2017年第5期7卷 141-153页

作者： Yasser bakr Mohamed Ula M. Al-Jarhi mona Mohsen Sarah Ahmad El Morsy Department of Medicine Cairo University Cairo Egypt Department of Chemical Pathology Cairo University Cairo Egypt Mataria Hospital Cairo Egypt

Background/Aims: Vascular Endothelial Growth Factor (VEGF) has a crucial role in portal hypertension and collateral vessels formation. This study aims to assess urinary VEGF in cirrhotic patients as a predictor of presence of esophageal varices, and variceal bleeding. Settings and Design: 42 cirrhotic patients were randomly selected and classified into 2 groups according to the presence of variceal bleeding. Methods and Material: Urinary VEGF was measured and corrected against urinary creatinine. Platelet count, liver functions, abdominal ultrasonography and upper endoscopy were done. Statistical Analysis Used: Comparison was done by Mann Whitney and Kruskal Wallis tests. Correlation was done using Spearman rank correlation. Multivariable logistic regression was done to identify predictors of variceal bleeding and presence of large varices. Receiver operator characteristic curve (ROC) analysis was used to determine the optimum cut off value of predictors. Results and Conclusions: Urinary VEGF was lower in cirrhotic patients with esophageal varices than those without. Low VEGF, low platelet count and splenomegaly were found to be independent predictors of both the presence of large esophageal varices, and variceal bleeding. Cut-off values for platelet count ≤ 166.3 × 103/μL, and corrected VEGF ≤ 59.12 pg/mg were predictive of large esophageal varices with 93.1%, 86.2% sensitivity and 74.5%, 58.2% specificity respectively. While variceal bleeding could be predicted at a platelet count ≤ 153 × 103/μL, and corrected VEGF ≤ 45.08 pg/mg with 90.9%, 81.8% sensitivity and 72.6%, 59.7% specificity respectively. The study concludes that urinary VEGF can be used as an alternative to upper endoscopic screening.

关键词： Liver Cirrhosis Portal Hypertension Esophageal Varices VEGF Variceal Bleeding

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：