114 research outputs found
6-loop anomalous dimension of a single impurity operator from AdS/CFT and multiple zeta values
Anomalous dimension of the simplest nontrivial single impurity operator in
the beta=1/2 deformed theory is determined at six loops from the AdS/CFT
correspondence. L\"uscher correction is evaluated at next-to-next-to-leading
order (NNLO) in terms of multiple zeta values. The result can be simplified
into the products of simple zeta functions and the same form of the correction
is expected for the Konishi operator at six loops, too.Comment: 14 pages, references added, numeric coefficient in (5) corrected,
which changes the numerical result, but not its structur
Recent Applications of Quantitative Structure-Activity Relationships in Drug Design
One of the most important challenges that face medicinal chemists today is the design of
new drugs with improved properties and diminished side-effects for treating human
disease such as AIDS and others. Medicinal chemists began the process by taking a lead
structure and then finding analogs exhibiting the preferred biological activities. Next, they
used their experience and chemical insight to eventually choose a nominee analog for
further development. This process is difficult, expensive and took a long time. The
conventional methods of drug discovery are now being supplemented by shortest
approaches made possible by the accepting of the molecular processes involved in the
original disease. In this view, the preliminary point in drug design is the molecular target
which is receptor or enzyme in the body as an option of the existence of known lead
structure
Discrete physical states and correction terms in the Supersymmetric c=1 Model of String Theory
In this work, we explore the example of supersymmetric c=1 model which is one
of the simplest models of superstrings, with an elegant and transparent
spectrum of physical states. We show how the presence of the ghost cohomologies
enlarges the spectrum of states and leads to new intriguing symmetries of the
theory and possibly leads to nontrivial relations of two-dimensional
supergravity with physical theories in higher dimensions. We develop a general
prescription for constructing the BRST-invariant and nontrivial vertex
operators and we explicitly compute correction terms that restore BRST
invariance of their corresponding currents.Comment: 15 pages. arXiv admin note: substantial text overlap with
arXiv:hep-th/0602209, arXiv:hep-th/0701044 by other author
Exploring QSARs for Inhibitory Activity of Non-peptide HIV-1 Protease Inhibitors by GA-PLS and GA-SVM
The support vector machine (SVM) and partial least square (PLS) methods were used to develop quantitative structure activity relationship (QSAR) models to predict the inhibitory activity of non-peptide HIV-1 protease inhibitors. Genetic algorithm (GA) was employed to select variables that lead to the best-fitted models. A comparison between the obtained results using SVM with those of PLS revealed that the SVM model is much better than that of PLS. The root mean square errors of the training set and the test set for SVM model were calculated to be 0.2027, 0.2751, and the coefficients of determination (R(2)) are 0.9800, 0.9355 respectively. Furthermore, the obtained statistical parameter of leave-one-out cross-validation test (Q(2)) on SVM model was 0.9672, which proves the reliability of this model. The results suggest that TE2, Ui, GATS5e, Mor13e, ATS7m, Ss, Mor27e, and RDF035e are the main independent factors contributing to the inhibitory activities of the studied compounds.The authors would like to acknowledge the computational chemistry
laboratory at Al-Quds University for providing Matlab software
and for the time dedicated for performing the calculations of the
study
Exploring Quantitative Structure-Activity Relationships (QSARs) of Non-Tri cyclic Cyclooxygenase-2 (COX-2) Inhibitors by MLR and PC-ANN
Quantitative structure–activity relationship study using principal component artificial neural network (PC-ANN) methodology was conducted to predict the inhibitory activities expressed as pIC50 of 73 non-tri cyclic cyclooxygenase-2 (COX-2) inhibitors. The results obtained by MLR shows that the best two models are close to each other with regression coefficient of 0.85. These optimal models were further analyzed by PC-ANN and the best model obtained was with regression coefficient of 0.823 for the test set. The lowest prediction sum of squares (PRESS) value obtained for the prediction set is 4.727 which accounts for predictability of the model. Artificial neural networks provide improved models for heterogeneous data sets without splitting them into families. Both the external and cross-validation methods are used to validate the performances of the resulting models. Randomization test is employed to check the suitability of the models
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