INSIGHT INTO THE STRUCTURAL REQUIREMENTS OF SULFONYL DERIVATIVES BASED ON TWO AND THREE-DIMENSIONAL DESCRIPTORS: QSAR STUDIES

INDIAN DRUGS ◽  
2019 ◽  
Vol 56 (01) ◽  
pp. 81-86
Author(s):  
M. C Sharma ◽  
Keyword(s):  
Nearest Neighbor ◽  
Three Dimensional ◽  
Structural Features ◽  
At1 Receptor ◽  
Field Analysis ◽  
K Nearest Neighbor ◽  
Qsar Studies ◽  
Contour Plots ◽  
The Relationship ◽  
Insight Into

The present work provides the rationale to the changes in the structure to have more potent analogs sulfonyl derivatives were reported to possess potent activity for the angiotensin AT1 receptor. We report here 2D QSAR and k-nearest neighbor molecular field analysis based model for sulfonylureas compounds as AT1 receptor. The here k-nearest neighbor contour plots provided further understanding of the relationship between structural features of substituted sulfonyl derivatives and their activities which should be applicable to design newer potential AT1 receptor.

THREE-DIMENSIONAL QSAR MODELING BENZIMIDAZOLE ANALOGUES USING THE K-NEAREST NEIGHBOR METHOD

INDIAN DRUGS ◽  
2019 ◽  
Vol 56 (12) ◽  
pp. 62-67
Author(s):  
M. C Sharma ◽  
◽  
D. V. Kohli
Keyword(s):  
Nearest Neighbor ◽  
Three Dimensional ◽  
Antihypertensive Agents ◽  
3D Qsar ◽  
Good Alternative ◽  
Qsar Model ◽  
Field Analysis ◽  
K Nearest Neighbor ◽  
Qsar Modeling ◽  
Qsar Studies

We undertook the three-dimensional (3D) QSAR studies of a series of benzimidazole analogues to elucidate the structural properties required for angiotensin II. The 3D-QSAR studies were performed using the stepwise, simulated annealing (SA) and genetic algorithm (GA) selection k-nearest neighbor molecular field analysis approach; a leave-one-out cross-validated correlation coefficient q2 = 0.8216 and a pred_r2 = 0.7852 were obtained. The 3D QSAR model is expected to provide a good alternative to predict the biological activity prior to synthesis as antihypertensive agents.

QSAR STUDIES ON HUMAN CARBONIC ANHYDRASE II INHIBITORS

INDIAN DRUGS ◽  
2021 ◽  
Vol 58 (11) ◽  
pp. 18-28
Author(s):  
Tanvi V. Wani ◽  
◽  
Mrunmayee P. Toraskar
Keyword(s):  
Carbonic Anhydrase ◽  
Nearest Neighbor ◽  
3D Qsar ◽  
Field Analysis ◽  
Molecular Field ◽  
Carbonic Anhydrase Ii ◽  
Carbonic Anhydrases ◽  
K Nearest Neighbor ◽  
Qsar Studies ◽  
Molecular Field Analysis

Carbonic anhydrase II is one of the forms of human α carbonic anhydrases which are ubiquitous metalloenzymes that catalyze inter-conversion of carbon dioxide and water to bicarbonate and proton, overexpression of which leads to disorders such as glaucoma. 2D and 3D Quantitative Structure Activity Relationship studies were carried out on previously synthesized series of sulfanilamide derivatives by VLife MDS software using stepwise variable, multi-linear regression and k-nearest neighbor molecular field analysis methods. 2D-QSAR model depicts contribution of halogens (such as chlorine and fluorine), methylene and oxygen atoms to inhibition of human carbonic anhydrases II activity. Using k-nearest neighbor molecular field analysis method two 3D-QSAR models (model A and B) were generated from which model A was found to be the best validated model with q2 (0.9494), pred_r2 (0.7367) and q2 _ se (0.2037). It displayed the fact that the inhibitory action of sulfanilamide derivatives against human carbonic anhydrases II is influenced by hydrophobicity and electro positivity.

DEVELOPMENT OF A CREDIBLE QSAR AND K NEAREST NEIGHBOR MODELS FOR IMIDAZOLYL DERIVATIVES

INDIAN DRUGS ◽  
2018 ◽  
Vol 55 (05) ◽  
pp. 7-13
Author(s):  
M. C Sharma ◽  
Keyword(s):  
Correlation Coefficient ◽  
Nearest Neighbor ◽  
Antihypertensive Agents ◽  
3D Qsar ◽  
Qsar Model ◽  
Structural Features ◽  
Field Analysis ◽  
Molecular Field ◽  
K Nearest Neighbor ◽  
Molecular Field Analysis

Quantitative Structure-Activity Relationship studies were performed for correlating the imidazolyl derivatives and their activity using molecular modeling studies. The statistically significant best 2D model was having correlation coefficient = 0.8221 and cross-validated squared correlation coefficient = 0.7534 with external predictive ability of pred_r2 = 0.7716. Molecular field analysis was used to construct the best 3D-QSAR model showing good correlative and predictive capabilities in terms of q2 =0.6781 and pred_r2 =0.7299. The molecular field analysis (MFA) contour plots provided further understanding of the relationship between structural features of Imidazolyl derivatives and their activities which should be applicable to design newer potential antihypertensive agents.

DESIGN OF POTENTIAL CYCLOOXYGENASE INHIBITORS USING PHARMACOPHORE OPTIMIZATION BY MOLECULAR MODELING STUDIES

INDIAN DRUGS ◽  
2015 ◽  
Vol 52 (12) ◽  
pp. 16-22
Author(s):  
S. S Todkar ◽  
◽  
A. H. Hoshmani
Keyword(s):  
Molecular Modeling ◽  
Nearest Neighbor ◽  
3D Qsar ◽  
Field Analysis ◽  
K Nearest Neighbor ◽  
Qsar Studies ◽  
2D Qsar ◽  
Molecular Modeling Studies ◽  
Cox 2 ◽  
Cox 2 Inhibitors

Recently discovery of relation between cyclooxygenase–2 (COX–2) inhibition and prevention of growth of cansar cells is a major area for research in medicinal chemistry, as it is free from side effects which are genetically shown by developed anticancer agents. In an attempt to develop potent and nontoxic COX–2 inhibitors, we have optimized the 1,5- diaryl pyrazole pharmacophore by using molecular modeling studies. In this paper we present results of 2D and 3D QSAR studies of a series of 22 molecules containing 1,5- diaryl pyrazole pharmacophore as selective COX–2 inhibitors. The 3D QSAR studies were performed using two different methods, stepwise variable selection k–nearest neighbor molecular field analysis (SW kNN–MFA) and simulated annealing k–nearest neighbor molecular field analysis (SA kNN–MFA) methods. The 2D QSAR studies were performed using multiple regressions. 3D QSAR studies produced reasonably good predictive models with high cross–validated r2cv value of 0.732 and 0.783 and predicted r2 value of 0.882 and 0.794 values using the models SW kNN–MFA and SA kNN–MFA method, respectively, whereas the r2 & predicted r2 value in 2D QSAR studies was found to be 0.84914 & 0.9157, respectively. the 2D QSAR studies indicated contribution of different physicochemical descriptors and the result of 3D QSAR studies indicated the exact steric and electronic requirement in the ranges at various positions in the 1,5- diaryl pyrazole pharmacophore. The pharmacophore requirement for selective COX–2 inhibition was optimized and requirement at various positions around 1, 5- diaryl pyrazole pharmacophore were defined.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

3D-QSAR Studies of S-DABO Derivatives as Non-nucleoside HIV-1 Reverse Transcriptase Inhibitors

2019 ◽  
Vol 16 (8) ◽  
pp. 868-881
Author(s):  
Yueping Wang ◽  
Jie Chang ◽  
Jiangyuan Wang ◽  
Peng Zhong ◽  
Yufang Zhang ◽  
...  
Keyword(s):  
Reverse Transcriptase ◽  
Three Dimensional ◽  
Predictive Ability ◽  
3D Qsar ◽  
Binding Mode ◽  
Quantitative Structure Activity Relationship ◽  
Field Analysis ◽  
Reverse Transcriptase Inhibitors ◽  
Qsar Studies ◽  
Hiv 1

Background: S-dihydro-alkyloxy-benzyl-oxopyrimidines (S-DABOs) as non-nucleoside reverse transcriptase inhibitors have received considerable attention during the last decade due to their high potency against HIV-1. Methods: In this study, three-dimensional quantitative structure-activity relationship (3D-QSAR) of a series of 38 S-DABO analogues developed in our lab was studied using Comparative Molecular Field Analysis (CoMFA) and Comparative Molecular Similarity Indices Analysis (CoMSIA). The Docking/MMFF94s computational protocol based on the co-crystallized complex (PDB ID: 1RT2) was used to determine the most probable binding mode and to obtain reliable conformations for molecular alignment. Statistically significant CoMFA (q2=0.766 and r2=0.949) and CoMSIA (q2=0.827 and r2=0.974) models were generated using the training set of 30 compounds on the basis of hybrid docking-based and ligand-based alignment. Results: The predictive ability of CoMFA and CoMSIA models was further validated using a test set of eight compounds with predictive r2 pred values of 0.843 and 0.723, respectively. Conclusion: The information obtained from the 3D contour maps can be used in designing new SDABO derivatives with improved HIV-1 inhibitory activity.

scholarly journals A Deep Learning Based Method for the Non-Destructive Measuring of Rock Strength through Hammering Sound

2019 ◽  
Vol 9 (17) ◽  
pp. 3484
Author(s):  
Shuai Han ◽  
Heng Li ◽  
Mingchao Li ◽  
Timothy Rose
Keyword(s):  
Clustering Algorithm ◽  
Nearest Neighbor ◽  
Rock Strength ◽  
Support Vector ◽  
K Nearest Neighbor ◽  
Strength Measurement ◽  
Regression Algorithms ◽  
Almost All ◽  
The Relationship ◽  
Non Destructive

Hammering rocks of different strengths can make different sounds. Geological engineers often use this method to approximate the strengths of rocks in geology surveys. This method is quick and convenient but subjective. Inspired by this problem, we present a new, non-destructive method for measuring the surface strengths of rocks based on deep neural network (DNN) and spectrogram analysis. All the hammering sounds are transformed into spectrograms firstly, and a clustering algorithm is presented to filter out the outliers of the spectrograms automatically. One of the most advanced image classification DNN, the Inception-ResNet-v2, is then re-trained with the spectrograms. The results show that the training accurate is up to 94.5%. Following this, three regression algorithms, including Support Vector Machine (SVM), K-Nearest Neighbor (KNN), and Random Forest (RF) are adopted to fit the relationship between the outputs of the DNN and the strength values. The tests show that KNN has the highest fitting accuracy, and SVM has the strongest generalization ability. The strengths (represented by rebound values) of almost all the samples can be predicted within an error of [−5, 5]. Overall, the proposed method has great potential in supporting the implementation of efficient rock strength measurement methods in the field.

2D and 3D QSAR Studies on a Series of Antichagasic Fenarimol Derivatives

2017 ◽  
Vol 2 (1) ◽  
pp. 44-63
Author(s):  
Anacleto S. de Souza ◽  
Leonardo G. Ferreira ◽  
Adriano D. Andricopulo
Keyword(s):  
Neglected Tropical Diseases ◽  
Public Health Problem ◽  
Predictive Ability ◽  
3D Qsar ◽  
Structural Features ◽  
Field Analysis ◽  
Global Public Health ◽  
Qsar Studies ◽  
Qsar Models ◽  
2D And 3D

Chagas disease is one of the most important neglected tropical diseases. Endemic in Latin America, the disease is a global public health problem, affecting several countries in North America, Europe, Asia and Oceania. The disease affects around 8-10 million people worldwide and the limited treatments available present low efficacy and severe side effects, highlighting the urgent need for new therapeutic options. In this work, the authors developed QSAR models for a series of fenarimol derivatives exhibiting anti-T. cruzi activity. The models were constructed using the Hologram QSAR (HQSAR), Comparative Molecular Field Analysis (CoMFA) and Comparative Molecular Similarity Indices Analysis (CoMSIA) methods. The QSAR models presented substantial predictive ability for a series of test set compounds (HQSAR, r2pred = 0.66; CoMFA, r2pred = 0.82; and CoMSIA, r2pred = 0.76), and were valuable to identify key structural features related to the observed trypanocidal activity. The results reported herein are useful for the design of novel derivatives having improved antichagasic properties.

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