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数字图像混沌序列抽样加权强置乱算法仿真
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作者 贺国平 张国荣 《计算机仿真》 2024年第10期192-195,350,共5页
数字图像置乱关系到个人隐私和信息安全问题,为了保护图像中的敏感信息,提出一种基于位交换和混沌优化的数字图像置乱算法。使用散列函数获得数字图像明文的密钥流,采用与明文相关的子密钥推导像素初始值,通过非线性交叉生成位交换算子... 数字图像置乱关系到个人隐私和信息安全问题,为了保护图像中的敏感信息,提出一种基于位交换和混沌优化的数字图像置乱算法。使用散列函数获得数字图像明文的密钥流,采用与明文相关的子密钥推导像素初始值,通过非线性交叉生成位交换算子,增强明文信息敏感性;运用Logistic方程得到混沌序列,引入抽样加权方法提高图像置乱强度,采用混合蛙跳方法按照族群划分实施信息传输,将混沌序列内的实数从小到大排列,初始混沌抽样后构成的混沌序列用于图像中,显著提升图像置乱强度,完成数字图像置乱。仿真结果表明,上述方法拥有极高的安全性和优秀的加密性能,可以为数字图像在各领域的安全使用提供可靠借鉴。 展开更多
关键词 位交换 混沌优化 数字图像 置乱算法 敏感性增强 混合蛙跳方法
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pE_6/p53/GFP重组真核表达载体的构建及其对肺腺癌细胞周期的影响 被引量:2
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作者 毛丽伟 王卫东 +1 位作者 李德志 陈正堂 《第三军医大学学报》 CAS CSCD 北大核心 2007年第24期2323-2326,共4页
目的构建放射诱导启动子序列所调控的wt-p53抑癌基因的真核表达载体pE6-p53/GFP,并研究其功能。方法全基因合成方法获得放射敏感性增强子E6;PCR法从pcDNA3.1(+)/p53质粒中扩增p53cDNA全长序列;双酶切IRES2-EGFP双顺反子表达载体,获得IRE... 目的构建放射诱导启动子序列所调控的wt-p53抑癌基因的真核表达载体pE6-p53/GFP,并研究其功能。方法全基因合成方法获得放射敏感性增强子E6;PCR法从pcDNA3.1(+)/p53质粒中扩增p53cDNA全长序列;双酶切IRES2-EGFP双顺反子表达载体,获得IRES2-EGFP报告基因片段,以pCI-neo为载体构建重组pE6/p53/GFP。重组体经双酶切、测序鉴定其正确性。采用脂质体法将重组质粒转染H1299(p53-/-)细胞,G418筛选出稳定表达细胞株。RT-PCR分析基因整合;Western blot方法分析不同放射剂量后P53蛋白表达情况及持续时间;流式细胞技术分析E6对肺腺癌细胞周期的影响。结果正确构建pE6/p53/GFP重组质粒,并在被转染细胞核内检测到p53基因表达;4Gy照射12h后p53基因表达显著增强;放疗后转染组细胞发生显著G1期阻滞,克隆形成率下降。结论成功构建了放射反应元件E6控导的pE6/p53/GFP重组质粒。 展开更多
关键词 放射敏感性增强 RT—PCR WESTERN BLOT
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Unrealistic treatment of detrained water substance in FGOALS-s2 and its influence on the model's climate sensitivity 被引量:2
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作者 HE Bian 《Atmospheric and Oceanic Science Letters》 CSCD 2016年第1期45-51,共7页
Based on a series of aqua-planet and air–sea coupled experiments,the influence of unrealistic treatment of water substance in the Flexible Global Ocean–Atmosphere–Land System Model,spectral version 2(FGOALS-s2),o... Based on a series of aqua-planet and air–sea coupled experiments,the influence of unrealistic treatment of water substance in the Flexible Global Ocean–Atmosphere–Land System Model,spectral version 2(FGOALS-s2),on the model's climate sensitivity is investigated in this paper.Because the model does not adopt an explicit microphysics scheme,the detrained water substance from the convection scheme is converted back to the humidity.This procedure could lead to an additional increase of water vapor in the atmosphere,which could strengthen the model's climate sensitivity.Further sensitivity experiments confirm this deduction.After removing the water vapor converted from the detrained water substance,the water vapor reduced significantly in the upper troposphere and the high clouds also reduced.Quantitative calculations show that the water vapor reduced almost 10% of the total water vapor,and 50% at 150 h Pa,when the detrained water substance was removed,contributing to the 30% atmospheric surface temperature increase.This study calls for an explicit microphysics scheme to be introduced into the model in order to handle the detrained water vapor and thus improve the model's simulation skill. 展开更多
关键词 FGOA Ls-s2 climate sensitivity cloud radiation global warming
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Enhanced chemosensitivity of p73α gene transferred into H1299 cell line of human lung adenocarcinoma 被引量:2
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作者 何勇 范士志 +2 位作者 Kalkunte S Srivenugopal 蒋耀光 秦川 《Journal of Medical Colleges of PLA(China)》 CAS 2004年第3期151-156,共6页
Objective: To study the effects of transferred wild type p73α gene on the sensitivity to the chemotherapeutic agents and the growth of p53-null H1299 cells of human lung adenocarcinoma. Methods: The pcDNA3-HA-p73α p... Objective: To study the effects of transferred wild type p73α gene on the sensitivity to the chemotherapeutic agents and the growth of p53-null H1299 cells of human lung adenocarcinoma. Methods: The pcDNA3-HA-p73α plasmid was transferred into the cultured p53-null H1299 cells of human lung adenocarcinoma with the mediation of Dosper liposome; The cells resistant to G418 were selected. The expression of p73α gene in the cells was examined with Western blot. MTT assay was used to analyze the response of the transfected cells to cis-dichlorodiamine platinum (cDDP) and adriamycin (ADM). The rate of drug-induced apoptosis of the transfected cells was determined with flow cytometry and DNA fragmentation assay. The changes of the biological behaviors were observed with colony formation assay. Results: The transfected H1299 cells of human lung adenocarcinoma over-expressed p73α protein stably. MTT assay showed that the IC 50 values of cDDP and ADM were reduced by approximately 7 fold and 130 fold respectively in the transfected cells as compared with the untransfected ones. Lower concentration of the chemotherapeutic agents (1.25 μmol/L of cDDP and 0.05 μmol/L of ADM) could be employed to suppress markedly the growth of the transfected H1299 cells. The apoptotic rate induced by cDDP was increased from 10.1% to 38 4% (P<0.01) and that of ADM from 12.1% to 49.3% (P<0.01). The clonogenecity after the administration of chemotherapeutic agents was significantly lower in the transfected H1299 cells than in the parental cells (P<0.01). The sensitive enhancement ratios were 1.8 and 2.6 for cDDP and ADM respectively. Conclusion: The transfection of H1299 cells with wild type p73α gene results in an increase of the sensitivity of the cells to chemotherapeutic agents. 展开更多
关键词 p73α gene lung adenocarcinoma gene therapy CHEMOSENSITIVITY
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磁共振功能成像技术在脑胶质瘤诊治中的应用 被引量:4
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作者 艾合买提.哈斯木 付强 +1 位作者 李绍山 刘波 《中华临床医师杂志(电子版)》 CAS 2015年第15期123-128,共6页
磁共振脑功能成像技术(f MRI)的着眼点在于利用某些特定的原子或化合物在磁场中的不同表现而对病变进行分析,从不同角度反映正常脑组织和肿瘤组织的功能和代谢变化,在研究和诊断中的作用正日益突出。在脑功能区或附近、深部脑胶质瘤手... 磁共振脑功能成像技术(f MRI)的着眼点在于利用某些特定的原子或化合物在磁场中的不同表现而对病变进行分析,从不同角度反映正常脑组织和肿瘤组织的功能和代谢变化,在研究和诊断中的作用正日益突出。在脑功能区或附近、深部脑胶质瘤手术致残率高、预后差。在常规MRI反映脑胶质瘤的解剖特征的基础上,f MRI提供有关肿瘤代谢、生化、脑白质纤维束的走行、脑功能区定位等信息,降低脑胶质瘤术后并发症等方面具有重要的应用价值。本文就目前几种常见的f MRI成像技术在胶质瘤诊治中的应用进行总结。 展开更多
关键词 神经胶质瘤 磁共振波谱 磁共振成像 弥散 血氧水平依赖成像 动态敏感对比增强磁共振灌注成像
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