Confiabilidade da análise qualitativa da ressonância magnética do encéfalo em prematuros extremos

OBJETIVO: O objetivo deste estudo foi avaliar a confiabilidade da análise visual qualitativa dos achados de imagem de ressonância magnética (RM) em recém-nascidos prematuros extremos. MATERIAIS E MÉTODOS: Uma coorte de 45 recém-nascidos de idade gestacional de 30 semanas ou menos foram inseridos neste estudo. Dois neurorradiologistas, cegos quanto aos dados clínicos, avaliaram de forma independente as RMs de crânio em relação aos seguintes achados: presença de hipersinal difuso e excessivo (DEHSI), dilatação dos ventrículos laterais, hemorragia intracraniana, áreas de sinal anormal em núcleos da base e córtex, áreas de aspecto cístico, deformidades ventriculares, dilatação do espaço subaracnóideo, leucoencefalomalácia precoce e anormalidades corticais. RESULTADOS: Quarenta e um pacientes (91,1%) apresentaram exame de RM anormal. Os achados mais comuns foram DEHSI (75,6%) e dilatação dos ventrículos (42,2%). A concordância interobservadores entre os dois experientes neurorradiologistas foi alta (κ > 0,60) para a maioria das alterações detectadas pela RM. O valor de kappa foi moderado (κ = 0,52) para alargamento do espaço subaracnoide e fraco (κ = 0,39) para DEHSI na substância branca. CONCLUSÃO: A avaliação qualitativa da maioria dos achados de imagem por RM de neonatos prematuros extremos foi considerada confiável, entretanto, a presença de DEHSI na substância branca demonstrou um grau de confiabilidade menor

Detecção de calcificação de aorta abdominal por densitometria

OBJETIVO: Analisar a acurácia da detecção de calcificação da aorta abdominal por meio de densitometria em comparação com a radiografia lateral de coluna. MATERIAIS E MÉTODOS: Casuística de 80 indivíduos, sendo 50 com diagnóstico de calcificação de aorta abdominal e 30 sem calcificação. Densitometria realizada uma única vez em cada participante, com o paciente em decúbito lateral direito. RESULTADOS: Em relação à idade e ao índice de massa corporal tivemos grupos semelhantes, com idade média de 74,56 ± 10,55 anos e 68,40 ± 10,80 anos e índice de massa corporal de 28,94 ± 6,06 kg/m² e 26,84 ± 4,11 kg/m² nos grupos com calcificação de aorta abdominal e sem calcificação de aorta abdominal, respectivamente. A comparação estatística da densitometria com a radiografia mostra que são semelhantes na detecção da calcificação de aorta abdominal, com valores de 100% na especificidade e valor preditivo positivo; sensibilidade de 94%, valor preditivo negativo de 90,9% e acurácia de 96,3%. Equivalência qualitativa no diagnóstico foi demonstrada pelo índice de correlação de kappa de 0,922. CONCLUSÃO: Os resultados da radiografia e da densitometria são estatisticamente equivalentes, o que permite sugerir a investigação de calcificação de aorta abdominal pela densitometria para a detecção de calcificação da aorta abdominal.

Investigação espectroscópica dos carbonilos heterobimetálicos cis-[Fe(CO)4(HgX)2], X = Cl, Br,I

The series of compounds cis-[Fe(CO)4(HgX)2], X=Cl,Br,I shows an octahedral geometry around the iron atom with the two HgX groups cis to each other. In this paper the assignment for the carbonyl stretching modes and the calculation of their force constants were performed on the basis of the Cotton-Krainhanzel model. Taking into account all the data from the IR, 199Hg NMR and UV-vis spectra it is possible to verify the influence of X on the electronic densities at the metallic centers.

Investigação de Er3+ nos dois sítios cristalográficos de Gd2SiO5 através da fotoluminescência resolvida no tempo

Gadolinium oxyortho-silicate, Gd2SiO5, presents a monoclinic structure with two crystallographic sites in which Gd3+ ions are equally distributed with coordination numbers CN, 7 and 9, respectively. By doping this host with Er3+ it is possible to distinguish and attribute the two sites by means of lifetime determination of the 4S3/2 state, (in this case, Er3+ substitutes Gd3+ ions). Samples doped with 0.1 and 5.0% molar Er3+ were prepared by solid state reaction and characterized by X-ray Diffractometry, Vibrational and Electronic Absorption Spectroscopies, and Time Resolved Photoluminescence. Based on the experimental results, it is possible to verify that, for the 5,0% doped sample, the lifetime value of the 4S3/2 state of the erbium ion inserted in site 1, (CN = 9), is 2.7 ± 0.1 mus, and for the one inserted in site 2, (CN = 7), it is 1.5 ± 0.1 mus.

Aplicações de QCM, EIS e SPR na investigação de superfícies e interfaces para o desenvolvimento de (bio)sensores

The use of the quartz crystal microbalance process, electrochemical impedance spectroscopy and surface plasmon resonance for characterizing thin films and monitoring interfaces is presented. The theorical aspects of QCM, EIS and SPR are introduced and the main application areas are outlined. Future prospects of the combined applications of QCM, EIS and SPR methods in the studies of interfacial processes at surfaces are also discussed.

A importância da Química Analítica Qualitativa nos cursos de Química das instituições de ensino superior brasileiras

The results of a survey of institutions offering undergraduate studies, with the objective of evaluating the importance of Qualitative Analytical Chemistry for Chemistry courses in Brazil, are presented and discussed. Judging by the data, the content of the course of Qualitative Analytical Chemistry is considered by the Brazilian institutions offering undergraduate studies to be a body of knowledge essential for the formation of the chemist. This aspect is deemed valid for both baccalaureate and teaching license studies.

Uma proposta para o ensino da Química Analítica Qualitativa

In recent years, because of the need for a more flexible curriculum established by the Curriculum Guidelines of the National Brazilian Education (law 9394/96), the pedagogical project of the Chemistry course of FFCLRP/USP has undergone alterations, amongst them the gradual reduction of the hours devoted to the discipline Qualitative Analytical Chemistry. In this context, this discipline has been carefully analyzed and reorganized in order to allow the elimination of redundancies and the introduction of activities considered important for the professional formation of both chemists and chemistry teachers. In this work, we will discuss the main strategies adopted in this reorganization with the objective of making the teaching/learning process more dynamic and efficient.

Investigação do potencial antioxidante e anticolinesterásico de Hippeastrum (Amaryllidaceae)

Amaryllidaceae family is an important source of bioactive molecules and considering the taxonomic relationships, it is relevant to investigate the genus Hippeastrum. Thus, the aim of this work was to determine antioxidant and anticholinesterasic activities of Hippeastrum morelianum, Hippeastrum psittacinum and Hippeastrum santacatarina. Both antioxidant and acetylcholinesterasic activities of extracts were determinated by bioautography as 10 mg/mL and 0.1 mg/mL, respectively. The antioxidant activity of alkaloid lycorine, determinated spectrophotometrically with DPPH, indicated an IC50 value of 0.326 mM.

Investigação do mecanismo de catálise ROMP do norborneno utilizando métodos de funcional de densidade

This work presents a density functional theory study of the norbornene ROMP metathesis reactions. The energies have been calculated in a Grubbs catalyst model Cl2(PH3)2Ru=CH2. The geometries and energy profile are similar to the Grubbs metilydene (Cl2(PCy3)2Ru=CH2 real model. It was found that the metathesis reaction proceeds via associative mechanism (catalyst-norbonene) followed by dissociative substitution of a phosphine ligand with norbonene, giving a monophosphine complex. The results are in reasonable agreement with the available experimental data. The dissociation energy of the phosphines is predicted to be 23.2 kcal mol-1.

Tratamento do efluente do biodiesel utilizando a eletrocoagulação/flotação: investigação dos parâmetros operacionais

Electrocoagulation/flotation process was applied to treat biodiesel wastewater using aluminium electrodes. Firstly, a literature survey was conducted to choose the process variables and then, operational parameters including initial pH, electrode distance and reaction time were tested. Experimental results showed the best parameter that can be used in a factorial design for further studies. The results indicate that electrocoagulation/flotation is very efficient to reduce oil and grease, the effluent was very clear after treatment and small amount of sludge was produced.

Investigação eletroquímica e calorimétrica da interação de novos agentes antitumorais biscatiônicos com DNA

Biscationic amidines bind in the DNA minor groove and present biological activity against a range of infectious diseases. Two new biscationic compounds (bis-α,ω-S-thioureido, amino and sulfide analogues) were synthesized in good yields and fully characterized, and their interaction with DNA was also investigated. Isothermal titration calorimetry (ITC) was used to measure the thermodynamic properties of binding interactions between DNA and these ligands. A double stranded calf thymus DNA immobilized on an electrode surface was used to study the possible DNA-interacting abilities of these compounds towards dsDNA in situ. A remarkable interaction of these compounds with DNA was demonstrated and their potential application as anticancer agents was furthered.

Alcaloides isoquinolínicos e investigação das atividades antiplasmódica e antibacteriana de Guatteria citriodora (Annonaceae)

Phytochemical investigations of the stem bark, leaves and twigs of Guatteria citriodora resulted in the isolation of eight alkaloids: liriodenine, lysicamine, O-methylmoschatoline, 3-methoxyoxoputerine, palmatine, 3-methoxyguadiscidine, guattescidine and oxoputerine. The structures of the isolated substances were established by extensive spectroscopic techniques (1D and 2D NMR) and mass spectrometry (MS), as well as by comparison with data reported in the literature. The in vitro antimalarial activity of the alkaloidal fractions of the leaves and twigs against Plasmodium falciparum FCR3 showed significant results, with IC50 = 1.07 and 0.33 mg mL-1, respectively. The alkaloidal fraction of the leaves showed moderate activity against Enterococcus faecalis, with IC50 = 125.0 mg mL-1. Antiplasmodial and antibacterial activities are attributed to alkaloidal constituents.

INVESTIGAÇÃO DO USO DE ELETRODO DE CARBONO VÍTREO MODIFICADO COM HEXACIANOFERRATO DE RUTÊNIO PARA DETECÇÃO DE PROCAÍNA

A glassy carbon electrode modified with ruthenium hexacyanoferrate (RuOHCF) was investigated as an electrocatalyst for the detection of procaine with the aim of quantification in pharmaceutical and forensic samples. The RuOHCF films were prepared by electrochemical deposition, and the parameters used in this process (concentration of RuCl3, K3Fe(CN)6, temperature, and number of cyclic voltammograms recorded in the modification step) were carefully optimized. Based on the optimal conditions achieved, the RuOHCF modified electrode allows the determination of procaine at 0.0 V with a detection limit of 11 nmol L-1using square wave voltammetry.

INVESTIGAÇÃO DA SUPRESSÃO DE FLUORESCÊNCIA DE SORO ALBUMINA BOVINA E HUMANA POR COMPLEXO DE RUTÊNIO

The binding of [RuCl2(L)] (L = N,N-bis(7-methyl-2-pyridylmethylene)-1,3-diiminopropane) to bovine and human serum albumin was investigated by the fluorescence quenching technique. The comparison of the quenching effect of serum albumin fluorescence by ruthenium complex allowed the estimation of subdomain IB in BSA and subdomain IIA in HSA as the binding sites for this complex. The results of fluorescence titration revealed that ruthenium complex quenches the intrinsic fluorescence of BSA through a dynamic quenching mechanism, while HSA has a static quenching mechanism. The thermodynamic parameters indicated that hydrophobic forces played a major role in the binding of ruthenium complex to proteins. The process of binding was a spontaneous process in which Gibbs free energy change was negative.