Studies of pear-shaped nuclei using accelerated radioactive beams.

There is strong circumstantial evidence that certain heavy, unstable atomic nuclei are 'octupole deformed', that is, distorted into a pear shape. This contrasts with the more prevalent rugby-ball shape of nuclei with reflection-symmetric, quadrupole deformations. The elusive octupole deformed nuclei are of importance for nuclear structure theory, and also in searches for physics beyond the standard model; any measurable electric-dipole moment (a signature of the latter) is expected to be amplified in such nuclei. Here we determine electric octupole transition strengths (a direct measure of octupole correlations) for short-lived isotopes of radon and radium. Coulomb excitation experiments were performed using accelerated beams of heavy, radioactive ions. Our data on (220)Rn and (224)Ra show clear evidence for stronger octupole deformation in the latter. The results enable discrimination between differing theoretical approaches to octupole correlations, and help to constrain suitable candidates for experimental studies of atomic electric-dipole moments that might reveal extensions to the standard model.

Development of QSAR for antimicrobial activity of substituted benzimidazoles.

QSAR analysis has been done to correlate antimicrobial activity of substituted benzimidazole derivatives with their physicochemical parameters. Developed QSAR models have been cross validated using leave one out (LOO) method. Statistical parameters like probable error of the coefficient of correlation (PE), least square error (LSE), Friedman's lack of fit measure (LOF), standard error of prediction (SEP) and quality value (Q) were also used to cross validate the models. QSAR studies established the importance of WAP, Mlog P and UI in describing the antimicrobial activities of substituted benzimidazole derivatives.

Topochemical models for prediction of anti-HIV activity of 4-benzyl pyridinone derivatives.

Relationship between topochemical indices and anti-HIV activity of 4-Benzyl pyridinone derivatives has been investigated. The values of molecular connectivity topochemical index (an adjacency based topochemical descriptor) Wiener's topochemical index (a distance based topochemical descriptor) and superadjacency topochemical index (an adjacency cum distance based topochemical descriptor) were calculated for each of the 32 compounds comprising the data set using an in-house computer program. The resultant data was analyzed and suitable models were developed after identification of the active ranges. Subsequently, a biological activity was assigned using these models to each of the compounds involved in the dataset which was then compared with the reported anti-HIV activity. Exceptionally high accuracy of prediction was observed using these models. These models offer vast potential for providing lead structures for the development of potent anti-HIV agents.

Topological models for prediction of anti-HIV activity of acylthiocarbamates.

Relationship of anti-HIV activity of acylthiocarbamates with distance based Wiener's index, adjacency based first-order molecular connectivity index and distance-cum-adjacency based augmented eccentric connectivity index was investigated. The values of all the three indices for each of the 61 compounds involved in the dataset were calculated using an in-house computer program. Resulting data was analyzed and suitable models were developed after identification of the active ranges. Subsequently, biological activity was assigned to each of the compounds involved in the dataset using these models which was then compared with the reported anti-HIV activity. Very high accuracy of prediction ranging from 95% to 98% was observed using these topological models.

Topochemical model for prediction of anti-HIV activity of HEPT analogs.

The relationship between the superadjacency topochemical index and the anti-HIV activity of HEPT analogs has been investigated in the present study. The values of superadjacency topochemical index of all the analogs involved in the data set were calculated using an in-house computer program. Resulting data were analyzed and a suitable model was developed after identification of the active range. Subsequently, a computed biological activity was assigned to each of the compounds involved in the dataset, which was then compared with the reported anti-HIV activity. Accuracy of prediction was found to be 88% using the said model. The predictive ability of the model indicates that this model can be used for predicting the anti-HIV activity of the compounds prior to synthesis and may prove to be highly beneficial for providing lead structures for development of potent anti-HIV agents.

Topological models for prediction of anti-inflammatory activity of N-arylanthranilic acids.

Relationship of anti-inflammatory activity of N-arylanthranilic acids with distance based Wiener's index, adjacency based Zagreb indices M1 and M2, and distance-cum-adjacency based eccentric connectivity index (ECI) was investigated. A dataset comprising of 112 N-arylanthranilic acids was selected. The values of all the four indices for each of the 112 compounds were calculated using an in-house computer program. The dataset was divided randomly into training and test sets. The data was analyzed and suitable models were developed after identification the active ranges in the training set. Subsequently, a biological activity was assigned to each of the compound involved in the test set using these models, which was then compared with the reported anti-inflammatory activity. High accuracy of prediction ranging from 83% to 90% was observed using models based upon topological indices.