Jardel Pinto Barbosa

COMPUTATIONAL MODELING OF ANTIMALARIAL 10-SUBSTITUTED DEOXOARTEMISININS

Nineteen 10-substitued deoxoartemisinin derivatives and artemisinin with activity against D-6 strains of malarial falciparum designated as Sierra Leone are studied. We use molecular electrostatic potential maps in an attempt to identify key structural features of the artemisinins that are necessary for their activities and molecular docking to investigate the interaction with the molecular receptor (heme). Chemometric modeling: Principal Component Analysis (PCA), Hierarchical Cluster Analysis (HCA), K-Nearest Neighbor (KNN), Soft Independent Modeling of Class Analogy (SIMCA) and Stepwise Discriminant Analysis (SDA) are employed to reduce dimensionality and investigate which subset of descriptors are responsible for the classification between more active (MA) and less active (LA) artemisinins. The PCA, HCA, KNN, SIMCA and SDA studies showed that the descriptors LUMO (Lowest Unoccupied Molecular Orbital) energy, DFeO1 (Distance between the O1 atom from ligand and iron atom from heme), X1A (Average Connectivity Index Chi-1) and Mor15u (Molecular Representation of Structure Based on Electron Diffraction) code of signal 15, unweighted, are responsible for separating the artemisinins according to their degree of antimalarial activity. The prediction study was done with a new set of eight artemisinins by using the chemometric methods and five of them were predicted as active against D-6 strains of falciparum malaria. In order to verify if the key structural features that are necessary for their antimalarial activities were investigated for the interaction with the heme, we also carried out calculations of the molecular electrostatic potential (MEP) and molecular docking. MEP maps and molecular docking were analyzed for more active compounds of the prediction set.

Chemometric Study on Molecules with Anticancer Properties

Cancer is a class of diseases characterized by uncontrolled growth of abnormal cells of an organism. All over the world millions of people die every year owing to one of the different types of cancer. Unfortunately cancer chemotherapy finds a serious limitation since treatment with drugs is followed by drug resistance in the tumorous cells and side effects (Efferth, 2005). So researches have been directed to make chemotherapy treatment more efficient.

Realistic fault analysis of CMOS analog building blocks

High quality analog and mixed signal integrated circuits (ICs) require high quality testing. It is shown that test preparation, and test quality improvement of analog building blocks must be layout driven. For this, an IC defects-based analysis is used to study the impact of catastrophic faults on basic CMOS analog blocks. The impact on circuit behavior is analyzed for functional test and for i/sub DD/ power supply fault signatures. It is also demonstrated that a significant part of catastrophic faults cause out of specs performance, and may thus decrease the yield of the product, by an apparent parametric yield degradation. Finally, it is shown that layout level DFT (design for testability) can be rewardingly used to increase test confidence and product quality.

Quantum Mechanical Study of YTiO3 to the Investigation of Piezoelectricity

In previous articles we reported through theoretical studies the piezoelectric effect in BaTiO3, SmTiO3, and YFeO3. In this paper, we used the Douglas-Kroll-Hess (DKH) second-order scalar relativistic method to investigate the piezoelectricity in YTiO3. In the calculations we used the [6s4p] and [10s5p4d] Gaussian basis sets for the O (3P) and Ti (5S) atoms, respectively, from the literature in combination with the (30s21p16d)/[15s9p6d] basis set for the Y (3D) atom, obtained by generator coordinate Hartree-Fock (GCHF) method, and they had their quality evaluated using calculations of total energy and orbital energies (HOMO and HOMO-1) of the 2TiO