结合边缘信息和图像特征信息的曲波域遥感图像融合

曲波变换是一种更适合于图像处理的多尺度几何分析方法,具有比小波变换更强的方向选择和辨识能力,而且对图像边缘的表达更优于小波.结合色度-饱合度-亮度变换将其应用于合成孔径雷达图像和多光谱图像融合可以更好地表示图像中的有用特征.首先对多光谱图像进行色度-饱合度-亮度变换,得到亮度分量I,对雷达图像和I分量进行曲波变换得到粗尺度系数和细节尺度系数;将雷达图像的粗尺度系数和细节尺度系数进行叠加,计算归一化的曲波系数直方图,定义边缘有效因子,利用合成孔径雷达图像的特征信息将曲波变换系数分为均匀区、非均匀区和亮点目标区.然后采用相应的融合规则对融合图像的粗尺度系数进行处理,对细节尺度系数采用简单的直接取大方法,逆变换后得到新的亮度分量.用新的亮度分量替代原亮度分量进行逆色度-饱合度-亮度变换得到最终融合结果,利用统计类指标对融合结果进行评价.实验结果表明,该方法在保持光谱信息和提高空间分辨率上都有较好的效果.     

Sar modeling of unbalanced data sets

Abstract

The increased acceptance of SAR approaches to hazard identification has led us to investigate methods to improve the predictive performance of SAR models. In the present study we demonstrate that although on theoretical grounds the ratio of active to inactive chemicals in the learning set should be unity, SAR models can ?tolerate‘ an unbalanced range in ratios from 3 : 1 (i.e., 75% actives) to 1 : 2 (i.e., 33% actives) and still perform adequately. On the other hand SAR models derived from learning sets with ratios in excess of 4 : 1 (80% actives), even when corrected for the initial ratio do not perform satisfactorily.     

ToxRead: A tool to assist in read across and its use to assess mutagenicity of chemicals

Life sciences, and toxicology in particular, are heavily impacted by the development of methods for data collection and data analysis; they are moving from an analytical approach to a modelling approach. The scarce availability of experimental data is a known bottleneck in assessing the properties of new chemicals. Even when a model is available, the resulting predictions have to be assessed by close scrutiny of the chemicals and the biological properties of the compounds concerned. To avoid unnecessary testing, a read across strategy is often suggested and used. In this paper we discuss how to improve and standardize read across activity using ad hoc visualization and data search methods which use similarity measures and fragment search to organize in a chart a picture of all the relevant information that the expert needs to make an assessment. We show in particular how to apply our system to the case of mutagenicity.     

SAR EVALUATION IN THE 0.25 MM HUMAN EYE MODEL EXPOSED TO 30 GHz MILLIMETER WAVE

We have evaluated the specific absorption rate (SAR) in the eye induced by the perpendicular incidence of 30 GHz uniform plane millimeter wave (MMW). An anatomically based 0.25 mm voxel model of the eye with 10 types of tissue is constructed. Debye’s dispersion equation is used to derive the dielectric properties of the eye tissues and biological materials in the neighboring region. The three-dimensional (3-D) finite-difference time-domain (FDTD) algorithm and the perfectly matched layer (PML) absorbing boundary conditions are used in the numerical simulation. The FDTD code is validated against the Mie theory. The SAR deposition in the eye is calculated and displayed, with the analysis on the SAR distribution characteristics. The average SAR values in the cornea, the lens cortex, the lens nucleus, the humor, and the whole eye are statistically derived and examined against present irradiation safety standard.     

Design,synthesis and immunomodulating activity of C-pseudonucleosides containing thiazolidin-4-one and phenyl connected by acetamide bond

Several novel C-pseudonucleosides containing thiazolidin-4-one and phenyl connected by acetamide bond were rationally designed and easily synthesized at room temperature by using the unprotected sugar aldehyde as the starting material. The effects of the compounds on Con A-induced T cell proliferation were evaluated at five concentrations of 5, 10, 25, 50, and 100 mmol/L Interestingly, compounds 7a and 8a (n = 2, R = H) exhibited immunostimulating activities, while compounds 5a, 6a (n = 1, R = H) and 7b, 8b (n = 2,R = CH₃) showed immunosuppressive activities. Another two compounds 5b and 6b (n = 1,R = CH3) had no immunomodulating activities. These initial biological results suggested that subtle structural changes to the phenyl and acetamide bond of C-pseudonucleosides could have a significant effect on T cell proliferation bias, although it was difficult to formulate a rigorous structureactivity relationship based on the observed activities.     

姜黄素的构效关系及以其为先导物的抗肿瘤化合物研究进展

姜黄素具有抗肿瘤、抗炎、抗菌、抗氧化等多种药理作用和确切疗效.近年来国内外科学家以姜黄素为先导物,设计、合成和表征了大量的姜黄素结构类似物和衍生物,以全面研究姜黄素的构效关系,并希望开发出更为高效的姜黄素类新药物.本文着重于介绍近年在抗肿瘤作用上针对姜黄素构效关系及其结构类似物进行的研究工作.     

Study on the quantitative structureactivity relation-ship of C-10 substituted artemisinin (QHS)’s derivatives using rough set theory

The structure-activity relationship study of C-10 substituted artemisinin (QHS) derivatives that are used as antimalarial was performed with the RS (rough sets) method. An RS process is a concise nonlinear process, and it has broad application foreground in the data mining of nonlinear life courses. In this work, initially the parameters of C-10 substituted QHS’s derivatives were computed with the quantum chemistry method, and the information table was constructed from the parameters (condition attributes) and biological activity (decision attributes). Based on the analysis of rough set theory, the core and reduction of attributes sets were obtained. Then the decision rules were extracted and the struc-ture-activity relationship was analyzed. As a nonlinear system, RS theory can extract the special rela-tion in the database. It has the advantage of being nonlinear over multiple linear regression (MLR), principal component analysis (PCA), partial least square (PLS), etc., and the advantage of obtaining results with unambiguous physical meanings over artificial neuron networks (ANNs), etc. The result obtained in this study is instructive to the study of pharmacodynamics, resistance mechanism of QHS and development of QHS’s derivatives.     

Synthesis,biological evaluation and molecular docking study of pyrimidine based thiazolidinone derivatives as potential anti-urease and anti-cancer agents

Hybrid analogs containing molecules are always the choice of different synthetic researcher due to their diverse biological applications and significantly more efficient. Heterocyclic being a good inhibitors against varied disease are most commonly used in drug designing and development. The current study also addressed the synthesis of pyrimidine-based thiazolidinone derivatives (1–13) using stepwise processes and their structure was confirmed using various characterization techniques such as ¹HNMR, ¹³CNMR, and HREI-MS. Furthermore, the biological significances of the synthesized scaffolds were also explored and proved to be as anti-urease and anti-cancer moieties. Their inhibitory potentials were determined using the minimum inhibitory concentration (MIC) in the presence of their standard drugs, Thiourea (IC₅₀ = 8.20 ± 0.20 µM) and Tetrandrineb (IC₅₀ = 12.30 ± 0.10 µM) respectively. Structure activity relationship (SAR) was established for all the synthesized scaffolds and compared their inhibitory potentials in which scaffolds 3 (IC₅₀ = 2.30 ± 0.30 and 3.20 ± 0.50 µM), 6 (IC₅₀ = 3.10 ± 0.20 and 6.20 ± 0.10 µM), 7 (IC₅₀ = 3.20 ± 0.20 and 3.80 ± 0.30 µM) and 10 (IC₅₀ = 4.20 ± 0.20 and 5.10 ± 0.30 µM) exhibited the most influential activity. These compounds were subsequently examined using molecular docking experiments, which evaluate the binding interaction of ligands with enzyme active sites.