Publications

Abstract Synthesis, characterization, and the optical behavior of CdS quantum dots nanoparticles, confined in zeolites, following a new synthesis approach in different natural zeolites mordenite, clinoptilolite, and syntheticZSM-5, were carried out. The composite materials are characterized by x-ray diffraction, Fourier transmission infrared spectroscopy, energy dispersive, scanning and transmission electron microscopy. After CdS-QDs formation, the synthesized materials become fluorescent with emission wavelengths (average and standard deviation of the maximum wavelength; full width of half maximum): Mordenite-CdS QDs (628 +/- 5 nm; 272 nm); clinoptilolite-CdS QDs (585 +/- 8 nm; 284 nm), and ZSM-5-CdS QDs (579 +/- 4 nm; 214 nm). [Supplemental materials are available for this article. Go to the publisher's online edition of the Journal of Dispersion Science and Technology to view the free supplemental file.]

Abstract Synthesis, characterization, and the optical behavior of CdS quantum dots nanoparticles were studied confined in clays. An alternative synthesis approach in different natural clays K-10 bentonite, Na-montemorillonite, halloysite, and saponite was carried out. The composite materials were characterized by XRD and FTIR spectroscopy, energy dispersive, scanning, and transmission electron microscopy. After CdS-QDs formation, the synthesized materials became fluorescent with emission wavelengths (average and standard deviation of the maximum wavelength; full width of half maximum): K-10 bentonite-CdS (590 +/- 5 nm; 183 nm); Na-montmorillonite-CdS (550 +/- 3 nm; 219 nm); saponite-CdS (550 +/- 5 nm; 219 nm), and halloysite-CdS (590 +/- 8 nm; 185 nm). (Supplemental materials are available for this article. Go to the publisher's online edition of the Journal of Dispersion Science and Technology to view the free supplemental file.)

Abstract The ability of pine bark and almond shells to remove bisphenol A (BPA) from aqueous solutions was evaluated. Samples of these traditional agro-forestry by-products were milled, sieved into different particle size fractions (0.10-0.15 and 1.5-2.0 mm) and submitted to two different types of treatment. Sorption experiments were conducted in a batch system at room temperature and natural pH. Sorption equilibrium was attained after 48 h for all systems under study. Bisphenol A was adsorbed more effectively on the smaller particles of the sorbents. Pine bark and almond shell pretreated with formaldehyde presented higher sorption efficiency (95%), followed by almond shell (87%) and pine bark (82%) washed with hot water. All the sorption isotherms were found to fit a Freundlich equation, with correlation coefficients (R-2) between 0.823 and 0.989. The sorption coefficient (K-F) ranged from 0.06 to 0.74 (mg(1-1/n).L-1/n.g(-1)). These results indicate that utilisation of both materials as an alternative sorbent for the removal of bisphenol A from contaminated waters is promising because they are available in large amounts and have an acceptable cost-efficiency ratio when compared with traditional adsorbents.

Abstract Fatty acids and cholesterol compositions, in both fresh and mature cheeses, prepared in accordance with the Manchego-type cheese with different fat compositions, using milk enriched with avocado oil were evaluated. Fresh cheese enriched with avocado oil showed an increase of 52% in polyunsaturated acids in full-fat milk and 98% in skimmed milk. Mature manchego style cheeses enriched with avocado oil showed an increase of 32% in polyunsaturated acids in full-fat milk and 61% in skimmed milk. Multivariate analysis (non-linear mapping, hierarchical cluster analysis, and linear discriminating analysis) of the fatty acids composition in newly prepared cheeses confirmed that they were different from the traditional cheeses and that a small set of fatty acids (myristoleic, lauroleic, eicosenoic, caproleic, stearic, palmitoleic, and margaroleic) can be used to develop classification rules.

Abstract The present work reports an energetic and structural study of 2-fluoro-, 3-fluoro-, and 4-fluorobenzonitrile. The standard molar enthalpies of formation, in the condensed phase, of the three isomers were derived from the standard molar energies of combustion, in oxygen, at T = 298.15 K. The standard molar enthalpies of vaporization or sublimation (for 4-fluorobenzonitrile), at T = 298.15 K, were measured using high-temperature Calvet microcalorimetry. The combination of these two parameters yields the standard molar enthalpies of formation in the gaseous phase. The vapor-pressure study of the referred compounds was performed by a static method, and the enthalpies of phase transition derived from the application of the Clarke and Glew equation. Theoretically estimated gas-phase enthalpies of formation, basicities, proton and electron affinities, and adiabatic ionization enthalpies were calculated from the G3MP2B3 level of theory. In order to evaluate the electronic properties, the geometries were reoptimized at MP2/cc-pVTZ level, and the QTAIM and NICS were computed. On the basis of the donor-acceptor system, another approach for evaluating the electronic effect for these compounds, using the NBO is suggested. The UV-vis spectroscopy study for the three isomers was performed. The intensities and the band positions were correlated with the thermodynamic properties calculated computationally.

Abstract The Knudsen mass-loss effusion technique was used to measure the vapour pressures of the three crystalline isomers of methylbenzamide. From the temperature dependence of the vapour pressures, the standard molar enthalpies of sublimation and the enthalpies of the intermolecular hydrogen bonds N-H center dot center dot center dot O were calculated. The temperature and molar enthalpy of fusion of the studied isomers were measured using differential scanning calorimetry. The values of the standard (p degrees = 0.1 MPa) molar enthalpy of formation in the crystalline phase, at T = 298.15 K, of the compounds studied were derived from their standard massic energies of combustion measured by static-bomb combustion calorimetry. From the experimental values, the standard molar enthalpies of formation in the gaseous phase, at T = 298.15 K, were calculated and compared with the values estimated by employing computational calculations that were conducted using different quantum chemical methods: G3( MP2), G3, and CBS-QB3. Good agreement between experimental and theoretical results is verified. The aromaticity of the compounds has been evaluated through nucleus independent chemical shifts (NICS) calculations.

Abstract Several 3-alkylaryl mimics of the enol intermediate in the reaction catalyzed by type II dehydroquinase were synthesized to investigate the effect on the inhibition potency of replacing the oxygen atom in the side chain by a carbon atom. The length and the rigidity of the spacer was also studied. The inhibitory properties of the reported compounds against type II dehydroquinase from Mycobacterium tuberculosis and Helicobacter pylori are also reported. The binding modes of these analogs in the active site of both enzymes were studied by molecular docking using GOLD 5.0 and dynamic simulations studies. © 2012 The Royal Society of Chemistry.

Abstract Quantitative Structure-Activity Relationships (QSAR) modeling tools play acritical role today in both drug design and environmental sciences. QSAR modeling seeksto discover and use mathematical relationships between molecular properties of thecompounds (descriptors) and the often complex activity of interest. An extensive numberof molecular descriptors exist which can and have been used to model a wide range oftarget activities. This complicates the task of selecting those that will be more suitable,especially when one tries to define an accurate, robust, predictive and (most importantly)interpretable model. Lately, recognition of the importance of the three-dimensionally (3D)structure and stereochemistry of molecules to their biological activity, and awareness of thelimitations of classical approaches, led to many attempts to generate 3D descriptors eitheras a complement for 2D-QSAR models or for standalone 3D-QSAR models. This reviewdescribes the 3D descriptors available in the DRAGON software along with theirsuccessful applications primarily in Medicinal Chemistry, updating a previously publishedpaper in Current Topics in Medicinal Chemistry (Helguera, A.M.; Combes, R.D.;González, M.P.; Cordeiro, M.N.D.S., 2008, 8, 1628-1655).

Abstract Blood Serum Proteome-Mass Spectra (SP-MS) may allow detecting Proteome-Early Drug Induced Cardiac Toxicity Relationships (called here Pro-EDICToRs).However, due to the thousands of proteins in the SP, a more realistic alternative representsthe identification of general Pro-EDICToRs patterns instead of a single protein marker. Inthis sense, we introduced a novel Cartesian 2D spectrum graph for SP-MS. Next, wecalculated the graph node-overlapping parameters (nopk) to numerically characterize SPMSby using them as inputs for a Quantitative Proteome-Toxicity Relationship (QPTR)classifier for Pro-EDICToRs with accuracy higher than 80%. This QPTR approach is theresult of adapting the classic blood proteome Quantitative Property-Structure Relationshipmodels (QSPR) used in Chemometrics to low-mass molecules study. Principal ComponentAnalysis (PCA) on the QPTR nopk values explains with one factor (F1) the 82.7% ofvariance. These nopk values were used to construct for the first time a Pro-EDICToRsComplex Network having samples as nodes linked by similarity between two samplesedges. We compared the topology of two sub-networks for the cardiac toxicity and controlsamples and found extreme relative differences for the re-linking (P) and Zagreb (M2)indices (9.5 and 54.2 % respectively) out of 11 parameters. We also compared the subnetworkswith the well-known ideal random networks including Barabasi-Albert,Kleinberg Small World, Erdos-Renyi, and Epsstein Power Law models. Finally, weproposed Partial Order (PO) schemes of the 115 samples based on LDA-probabilities, F1-scores and/or network node degrees. PCA-CN and LDA-PCA based POs with Tanimoto's.

Abstract The adjustment of multiple criteria in hit-to-lead identification and lead optimization is a major advance in drug discovery. Thus, the development of approaches able to handle additional criteria for the early simultaneous treatment of the most important properties determining the pharmaceutical profile of a drug candidate is an emergent issue in this area. In this paper, we review a desirability-based multi-objective QSAR method allowing the joint handling of multiple properties of interest in drug discovery: the MOOP-DESIRE methodology. This methodology adapts desirability theory concepts allowing the holistic modeling of the many and conflicting biological properties determining the therapeutic utility of a drug candidate. Here we survey their suitability for key tasks involving the use of chemoinformatics methods in medicinal chemistry and drug discovery.