Assessment of intima-media complex in carotid, femoral and right subclavian arteries for early investigation of atherosclerosis in HIV-infected patients

Objective To compare automatic and manual measurements of intima-media complex (IMC) in common carotid, common femoral and right subclavian arteries of HIV-infected patients in relation to a control group, taking into consideration the classical risk factors for atherosclerosis. Materials and Methods The study sample comprised 70 HIV-infected patients and 70 non-HIV-infected controls paired according sex and age. Automatic (gold standard) and manual measurements of IMC were performed in the carotid arteries. Manual measurements were also performed in common femoral and right subclavian arteries. Bland-Altman graphs were utilized in the comparison and the adopted level significance was 5%. Results Intima-media complex alterations were not observed in any of the individuals as the mean automatic measurement in the right common carotid (RCC) artery was considered as the gold standard. As the gold standard was compared with the manual measurements (mean, maximum and minimum), no clinically significant alteration was observed. As the gold standard was compared with other sites, the difference was statistically and clinically significant at the origin of right subclavian artery (RCC: 0.51 mm vs. 0.91 mm) (p < 0.001). Conclusion HIV-infected individuals are not at higher risk for atherosclerosis than the control population.

Propriedades espectroscópicas Ab initio dos dímeros de van der waals Ne2 e Ar2

Results of high level ab initio calculations of the intermolecular potentials and theoretical dispersion coefficients for the Ne2 and Ar2 dimers were utilized to build analytical potentials for these species. The obtained potentials were used in the calculation of the dimers rovibrationals levels, and their respective spectroscopic constants determined. A comparison of high level experimental data with our theoretical results shows a very good agreement for Ne2, and also a good agreement for the Ar2 dimer.

Optical characterization of sol-gel glasses derived from Eu3+ complex-forming precursors

Fabrication of new optical devices based upon the incorporation of rare earth ions via sol-gel methods depends on elimination of dopant ion clusters and residual hydroxyl groups from the final material. The optical absorption and/or luminescence properties of luminescent rare earth ions are influenced by the local bonding environment and the distribution of the rare-earth dopants in the matrix. Typically, dopants are incorporated into gel via dissolution of soluble species into the initial precursor sol. In this work, Eu3+ is used as optical probe, to assess changes in the local environment. Results of emission, excitation, fluorescence line narrowing and lifetimes studies of Eu3+-doped gels derived from Si(OCH3)4 and fluorinated/chelate Eu3+ precursors are presented. The precursors used in the sol-gel synthesis were: tris (6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionate) Eu(III), Eu (III) trifluoromethanesulfonate, Eu(III) acetylacetonate hydrate, Eu (III) trifluoroacetate trihidrate, tris (2,2,6,6-tetramethyl-3,5- heptanedionate) Eu(III) and Eu(NO3)3.6H2O. The results were interpreted in terms of the evolution of the Eu3+ fluorescence in systems varying from solution to the gels densified to 800ºC. The lifetimes studies indicate that the fluorinated precursors are effective at reducing the water content in densified gels.

The determination of the stoichiometry of the mixed complex of vanadium with hydrogen peroxide and with 4-(2-Pyridilazo) Resorcinol

The present study reports details of the stoichiometric characterization of the mixed complex system, V(H2O2)PAR, formed when vanadium adequately reacts with hydrogen peroxide and with 4-(2-Pyridilazo)Resorcinol. Also the presence of polynuclear species was investigated in order to elucidate about unambiguous assignment of the molar absorptivity, stability constant and composition of the complex. Two mathematical treatments methods of the experimental results were employed. From the results it can be concluded that this system corresponds to a mononuclear complex with 1:1:1 stoichiometry.

Inclusion complex of the antiviral drug acyclovir with cyclodextrin in aqueous solution and in solid phase

Complexation between acyclovir (ACV), an antiviral drug used for the treatment of herpes simplex virus infection, and beta-cyclodextrin (beta-CD) was studied in solution and in solid states. Complexation in solution was evaluated using solubility studies and nuclear magnetic resonance spectroscopy (¹H-NMR). In the solid state, X-ray diffraction, differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA) and dissolution studies were used. Solubility studies suggested the existence of a 1:1 complex between ACV and beta-CD. ¹H-NMR spectroscopy studies showed that the complex formed occurs with a stoichiometry ratio of 1:1. Powder X-ray diffraction indicated that ACV exists in a semicrystalline state in the complexed form with beta-CD. DSC studies showed the existence of a complex of ACV with beta-CD. The TGA studies confirmed the DSC results of the complex. Solubility of ACV in solid complexes was studied by the dissolution method and it was found to be much more soluble than the uncomplexed drug.

Phase diagram and complex patterns in the modeling of the bromate-oxalic acid-Ce-acetone oscillating reaction

Simulations have been carried out on the bromate - oxalic acid - Ce(IV) - acetone oscillating reaction, under flow conditions, using Field and Boyd's model (J. Phys. Chem. 1985, 89, 3707). Many different complex dynamic behaviors were found, including simple periodic oscillations, complex periodic oscillations, quasiperiodicity and chaos. Some of these complex oscillations can be understood as belonging to a Farey sequence. The many different behaviors were systematized in a phase diagram which shows that some regions of complex patterns were nested with one inside the other. The existence of almost all known dynamic behavior for this system allows the suggestion that it can be used as a model for some very complex phenomena that occur in biological systems.

Synthesis, characterization, DFT and Td-dfT study of the [Fe(mnt)(L)(t-BuNC) 2] octahedral complex (L = phen, bipy)

FeBr2 has reacted with an equivalent of mnt2- (mnt = cis-1,2-dicyanoethylene-1,2-dithiolate) and the α-diimine L (L = 1,10'-phenantroline, 2,2'-bipyridine) in THF solution, and followed by adding of t-butyl-isocyanide to give [Fe(mnt)(L)(t-BuNC)2] neutral compound. The products were characterized by infrared, UV-visible and Mössbauer spectroscopy, besides thermogravimetric and conductivity data. The geometry in the equilibrium was calculated by the density functional theory and the electronic spectrum by the time-dependent. The experimental and theoretical results in good agreement have defined an octahedral geometry with two isocyanide neighbours. The π→π* intraligand electronic transition was not observed for cis-isomers in the near-IR spectral region.

Selective and non-extractive spectrophotometric determination of cefdinir in formulations based on donor-acceptor complex formation

Cefdinir has broad spectrum of activity and high prescription rates, hence its counterfeiting seems imminent. We have proposed a simple, fast, selective and non-extractive spectrophotometric method for the content assay of cefdinir in formulations. The method is based on complexation of cefdinir and Fe under reducing condition in a buffered medium (pH 11) to form a magenta colored donor-acceptor complex (λ max = 550 nm; apparent molar absorptivity = 3720 L mol-1 cm-1). No other cephalosporins, penicillins and common excipients interfere under the test conditions. The Beer's law is followed in the concentration range 8-160 µg mL-1.

Determination of aluminum in food samples after preconcentration as aluminon complex on microcrystalline naphthalene by spectrophotometry

A sensitive preconcentration procedure for spectrophotometeric determination of aluminum was developed. Aluminum as aluminon complex is adsorbed on microcrystalline naphthalene. The naphthalene containing the complex is dissolved in 3 mL of acetone and its absorbance is measured at 544 nm. The effect of various factors on the preconcentration of aluminum was investigated. The calibration graph was linear in the range of 1-60 mg L-1. The limit of detection was 0.52 mg L-1 and relative standard deviation for the determination of 5 mg L-1 was 2.65%. The proposed solid phase extraction procedure was applied to determination of aluminum in food samples.

Optimization of a HPLC procedure for simultaneous determination of cisplatin and the complex cis,cis,trans-diamminedichlorodihydroxoplatinum(IV) in aqueous solutions

A RP-HPLC procedure for the simultaneous determination of cisplatin and the complex cis,cis,trans-diamminedichlorodihydroxo-platinum(IV), was development. The developed procedure was validated in terms of linearity, accuracy, precision, limits of detection (LOD), limits of quantification (LOQ) and specificity. The limits of detection (LOD) were 0.47 x 10-4 and 0.53 x 10-4 mol L-1 and the limits of quantification (LOQ) were 1.57 x 10-4 and 1.75 x 10-4 mol L-1, for cisplatin and cis,cis,trans-diamminedichlorodihydroxopla-tinum(IV), respectively. The average recoveries of cisplatin and cis,cis,trans-diamminedichlorodihydroxoplatinum(IV) was 100.6% ± 1.4 and 101.2% ± 1.1, respectively. Intermediate (inter-day) precision, repeatability and specificity of the procedure for hydrolysis products of cisplatin were studied. The results of the study showed that the proposed RP-HPLC procedure is simple, rapid, precise, accurate and specific.

Ternary surface complex: coadsorption of Cu(II), Zn(II), Cd(II) and nitrilotris(methylenephosphonic) acid onto boehmite

This work studies the effect of NTMP (nitrilotris(methylenephosphonic acid)) on the adsorption of Cu(II), Zn(II), and Cd(II) onto boehmite in the pH range 5-9.5. The data were analyzed using the 2-pK constant capacitance model (CCM) assuming ternary surface complex formation. Under stoichiometric conditions, NTMP is more effective for removing Cu(II) than Zn(II) from solution and the contribution of ternary surface complexes are important to model the adsorption of both metals. Under nonstoichiometric conditions and high surface loading with a Me(II)/NTMP ratio of 1:5, Cu(II) and Zn(II) adsorption is significantly suppressed. In the case of Cd(II) the free metal adsorption is the most dominant species.

Preparation and immobilization of diNOsarcobalt(III) complex in zeolite y for the catalyzed production of hydrogen peroxide

A complex cation, diNOsarcobalt(III), [Co(diNOsar)]3+, (diNOsar = 1,8-dinitro-3,6,10,13,16,19-hexaazabicyclo-[6.6.6]eicosane), was synthesized and immobilized in the cavities of a Y zeolite by the reaction of precursor species in the pores of the zeolite. The encapsulated material was compared to the compound diNOsarcobalt(III) chloride, [Co(diNOsar)]Cl3. Both diNOsarcobalt(III) chloride and the zeolite-encapsulated complex, [Co(diNOsar)]3+/zeolite, were obtained in high yield and characterized by ultraviolet-visible and infrared spectroscopy. X-ray diffraction demonstrated the incorporation of the complex cation into the pores of the zeolite. The catalytic production of hydrogen peroxide from oxygenated water confirmed the successful synthesis of the complex diNOsarcobalt(III) immobilized in the zeolite.

INTERACTIONS: DESIGN, IMPLEMENTATION AND EVALUATION OF A COMPUTATIONAL TOOL FOR TEACHING INTERMOLECULAR FORCES IN HIGHER EDUCATION

Intermolecular forces are a useful concept that can explain the attraction between particulate matter as well as numerous phenomena in our lives such as viscosity, solubility, drug interactions, and dyeing of fibers. However, studies show that students have difficulty understanding this important concept, which has led us to develop a free educational software in English and Portuguese. The software can be used interactively by teachers and students, thus facilitating better understanding. Professors and students, both graduate and undergraduate, were questioned about the software quality and its intuitiveness of use, facility of navigation, and pedagogical application using a Likert scale. The results led to the conclusion that the developed computer application can be characterized as an auxiliary tool to assist teachers in their lectures and students in their learning process of intermolecular forces.