Chagas disease is a public health problem, affecting about 7 million people worldwide. Benznidazole (BZN) is the main treatment option, but it has limited effectiveness and can cause severe adverse effects. Drug delivery through nanoparticles has attracted the interest of the scientific community aiming to improve therapeutic options. The aim of this study was to evaluate the cytotoxicity of benznidazole-loaded calcium carbonate nanoparticles (BZN@CaCO3) on Trypanosoma cruzi strain Y. It was observed that BZN@CaCO3 was able to reduce the viability of epimastigote, trypomastigote and amastigote forms of T. cruzi with greater potency when compared with BZN. The amount of BZN necessary to obtain the same effect was up to 25 times smaller when loaded with CaCO3 nanoparticles. Also, it was observed that BZN@CaCO3 enhanced the selectivity index. Furthermore, the cell-death mechanism induced by both BZN and BZN@CaCO3 was evaluated, indicating that both substances caused necrosis and changed mitochondrial membrane potential.

We present the structural, electronic, and optical properties of anhydrous crystals of DNA nucleobases (guanine, adenine, cytosine, and thymine) found after DFT (Density Functional Theory) calculations within the local density approximation, as well as experimental measurements of optical absorption for powders of these crystals. Guanine and cytosine (adenine and thymine) anhydrous crystals are predicted from the DFT simulations to be direct (indirect) band gap semiconductors, with values 2.68 eV and 3.30 eV (2.83 eV and 3.22 eV), respectively, while the experimentally estimated band gaps we have measured are 3.83 eV and 3.84 eV (3.89 eV and 4.07 eV), in the same order. The electronic effective masses we have obtained at band extremes show that, at low temperatures, these crystals behave like wide gap semiconductors for electrons moving along the nucleobases stacking direction, while the hole transport are somewhat limited. Lastly, the calculated electronic dielectric functions of DNA nucleobases crystals in the parallel and perpendicular directions to the stacking planes exhibit a high degree of anisotropy (except cytosine), in agreement with published experimental results.

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The X-ray diffraction data of L-serine anhydrous crystals was taken into account to initialize the total energy minimization process of their unit cell through density functional theory (DFT) computations, which were performed within both the local density and generalized gradient approximations with dispersion, LDA, and GGA+D, respectively. The calculated lattice parameters are in good agreement with the experimental results for the dispersion corrected generalized gradient approximation functional, with a unit cell volume larger by only about 0.32%; the Mulliken and Hirschfield charges show the zwitterionic state of the L-serine molecules in the DFT converged crystals. The electronic (band structure, density of states) and optical absorption properties were calculated to explain the light absorption of the L-serine anhydrous crystalline powder we have measured at room temperature. The optical absorption related to transitions between the top of the valence band and the bottom of the conduction band involves O-2p valence states and H-1s conduction states. The LDA (4.74 eV) and GGA+D (4.75 eV) estimated energy gaps are about 1 eV below the estimated value from optical absorption measurements (5.90 eV). Small values were obtained for the electron effective masses, which are almost isotropic, whereas large anisotropic values were found for hole effective masses, suggesting that the Lserine anhydrous crystal behaves like an n-type wide gap semiconductor. Different dielectric function profiles obtained for some of the most important symmetry directions also demonstrate the optical anisotropy of L-serine anhydrous crystals.

Aiming at the development of novel NO donors, the synthesis and reactivity of the trans- [Ru(bpy)

This work presents the synthesis, characterization and the thermal study of 5-n-pentadecyl-2-tert-amylphenol (alkylphenol), which was synthesized by alkylation of 3-n-pentadecylphenol. For this study were employed termogravimetry (TG), derivative termogravimetry (DTG), differential scanning calorimetry (DSC), and differential thermal analysis (DTA) techniques. Hydrogenated naphthenic oil was submitted to accelerated oxidation tests in the presence and absence of alkylphenol according to modified ASTM D-2440 method. The addition of 1% of alkylphenol to the oil has reduced the carbonyl and peroxides bands areas: 1.00-1.00 (without alkylphenol) and 0.59-0.51 (with alkylphenol) respectively. The results showed that alkylphenol reduced significantly the formation of oxidation products in the oil analyzed. TG/DTG curves showed that 5-n-pentadecyl-2-tert-amylphenol is more stable than 2,6-di-t-butyl-4-methylphenol (BHT) when analyzed in different atmospheres: 143°C in air and nitrogen against 87°C in air for BHT.

Prostate cancer is one of the most common malignant tumors in males and it has become a major worldwide public health problem. This study characterizes the encapsulation of Nor-β-lapachone (NβL) in poly(D,L-lactide-co-glycolide) (PLGA) microcapsules and evaluates the cytotoxicity of the resulting drug-loaded system against metastatic prostate cancer cells. The microcapsules presented appropriate morphological features and the presence of drug molecules in the microcapsules was confirmed by different methods. Spherical microcapsules with a size range of 1.03˘0.46 µm were produced with an encapsulation efficiency of approximately 19%. Classical molecular dynamics calculations provided an estimate of the typical adsorption energies of NβL on PLGA. Finally, the cytotoxic activity of NβL against PC3M human prostate cancer cells was demonstrated to be significantly enhanced when delivered by PLGA microcapsules in comparison with the free drug.

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