Host-guest complexation of a nitroheterocyclic compound with cyclodextrins: a spectrofluorimetric and molecular modeling study

Nitroheterocyclic compounds (NC) were candidate drugs proposed for Chagas disease chemotherapy. In this study, we investigated the complexation of hydroxymethylnitrofurazone (NFOH), a potential antichagasic compound, with alpha-cyclodextrin (alpha-CD), beta-cyclodextrin (beta-CD), Hydroxypropyl-beta-cyclodextrin (HP-beta-CD), Dimethyl-beta-cyclodextrin (DM-beta-CD) and gamma-cyclodextrin (gamma-CD) by fluorescence spectroscopy and molecular modeling studies. Hildebrand-Benesi equation was used to calculate the formation constants of NFOH with cyclodextrins based on the fluorescence differences in the CDs solution. The complexing capacity of NFOH with different CDs was compared through the results of association constant according to the following order: DM-beta-CD > beta-CD > alpha-CD > HP-beta-CD > gamma-CD. Molecular modeling studies give support for the experimental assignments, in favor of the formation of an inclusion complex between cyclodextrins with NFOH. This is an important study to investigate the effects of different kinds of cyclodextrins on the inclusion complex formation with NFOH and to better characterize a potential formulations to be used as therapeutic options for the oral treatment of Chagas disease.

Study of spectroscopic properties of Europium (III) Tris(beta-diketonate) complex and alpha-Cyclodextrin in aqueous medium

The solubilization of an europium (III) beta-diketonate chelate in aqueous medium and the changes in its photophysical properties upon its inclusion into an alpha-cyclodextrin hydrophobic cavity are described. The complex [Eu(tta)(3)center dot(H(2)O)(2)] (tta = 4,4,4-trifluoro-1-(thiophen-2-yl)butane-1,3-dione) was synthesized, characterized, and incorporated into the hydrophobic cavity by stirring in an alpha-cyclodextrin aqueous solution. The inclusion was confirmed by (1)H NMR, and the stoichiometry of association was obtained by the Job method. The maximum in the excitation spectrum of the alpha-CD inclusion compound in aqueous solution was shifted 28 nm compared with the maximum of non alpha-CD complex. The emission spectrum of the association is similar to that of the free solid complex and displays the characteristic (5)D(0) -> (7)F(0-4) Eu(3+) transitions.

The John Dewey`s epistemology and informational literacy

The `reflexive thinking` concept is discussed in this article as a means of contextualizing John Dewey`s intellectual legacy. `Reflection` represents a fundamental element for the construction of the necessary competences to information seeking and use, and consequently to individual and collective development. Since the reflexive thinking habit in information literacy is a way of learning, some questions concerning teaching and learning processes are also investigated. The discussion is, therefore, supported by the supposition that reflexive thinking is a cognitive strategy that allows a deeper comprehension of related problems, phenomena, and processes by means of the perception of the relations and the identification of involved elements, as well as the analysis and interpretation of meanings, empowering the information literacy process.

Emotional trauma and abuse in patients with psychogenic nonepileptic seizures

A history of childhood trauma and the presence of dissociative phenomena are considered to be the most important risk factors for psychogenic nonepileptic seizure disorder (PNESD). This case-control study investigated 20 patients with PNESD and 20 with temporal lobe epilepsy (TLE) diagnosed by video/EEG monitoring who were matched for gender and age. Patients with both conditions were not included in the study. Groups were evaluated for age at onset and at diagnosis, worst lifetime weekly seizure frequency, trauma history, and presence of dissociative phenomena. Age at onset (P = 0.007) and age at diagnosis (P < 0.001) were significantly higher in the PNESD group than the control group, as were the scores on the Dissociative Experiences Scale (P < 0.001) and Childhood Trauma Questionnaire (P = 0.014). Only the differences in scores on the Childhood Trauma Questionnaire subscales Emotional Neglect (P = 0.013) and Emotional Abuse (P = 0.014) reached statistical significance. Dissociative phenomena and a reported history of childhood trauma are more common in patients with PNESD than in those with TLE. However, only emotional neglect and abuse were associated with PNESD in this study. (C) 2010 Elsevier Inc. All rights reserved.

Obsessive-compulsive symptoms and disorder in patients with schizophrenia treated with clozapine or haloperidol

We conducted a cross-sectional study to compare the prevalence and severity of obsessive-compulsive symptoms (OCSs) and obsessive-compulsive disorder (OCD) in patients with schizophrenia treated with clozapine or haloperidol. Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Axis I disorders-patient edition was used to diagnose schizophrenia and OCD. Sixty subjects, 40 of them using clozapine and 20 using haloperidol, completed the Yale-Brown Obsessive-Compulsive Scale, the Positive and Negative Syndrome Scale (PANSS), and the Clinical Global Impression. The prevalence of OCD in patients taking clozapine was 20%, whereas the prevalence of patients taking haloperidol was 10%, although this difference was not statistically significant (P = .540). However, patients using clozapine showed higher severity of OCSs than patients using haloperidol (P = .027) did. When schizophrenia patients were divided according to the presence or absence of OCD or OCSs, patients with schizophrenia and OCD or OCSs showed higher severity of schizophrenia symptoms when compared to those with schizophrenia without OCD and OCSs (P = .002). A PANSS total score higher than 70 and the use of antidepressants were predictors of the presence of OCSs or OCD. Schizophrenia patients taking clozapine had higher severity scores both in obsessive-compulsive and schizophrenia rating scales. These results may support an association between the exacerbation of obsessive-compulsive phenomena and the use of clozapine. (C) 2009 Elsevier Inc. All rights reserved.

Host-guest system of 4-nerolidylcatechol in 2-hydroxypropyl-beta-cyclodextrin: preparation, characterization and molecular modeling

The interaction of 4-nerolidylcatechol (4-NRC), a potent antioxidant agent, and 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CD) was investigated by the solubility method using Fourier transform infrared (FTIR) methods in addition to UV-Vis, (1)H-nuclear magnetic resonance (NMR) spectroscopy and molecular modeling. The inclusion complexes were prepared using grinding, kneading and freeze-drying methods. According to phase solubility studies in water a B(S)-type diagram was found, displaying a stoichiometry complexation of 2:1 (drug:host) and stability constant of 6494 +/- A 837 M(-1). Stoichiometry was established by the UV spectrophotometer using Job`s plot method and, also confirmed by molecular modeling. Data from (1)H-NMR, and FTIR, experiments also provided formation evidence of an inclusion complex between 4-NRC and HP-beta-CD. 4-NRC complexation indeed led to higher drug solubility and stability which could probably be useful to improve its biological properties and make it available to oral administration and topical formulations.

O adolescente e o diabetes: uma experiência de vida

OBJETIVO: Compreender como o adolescente com diabetes mellitus tipo I vivencia sua experiência de doença e como lida com esta situação no cotidiano. MÉTODOS: O Interacionismo Simbólico foi utilizado como referencial teórico e a Teoria Fundamentada nos Dados como o referencial metodológico da pesquisa. Participaram do estudo 10 adolescentes com diagnóstico de diabetes mellitus tipo 1 há mais de um ano. RESULTADOS: Foram identificados dois fenômenos explicativos da experiência: não sendo normal ter diabetes e sendo normal ter diabetes. CONCLUSÃO: Os dois fenômenos não são isolados ou excludentes para o mesmo adolescente, parecendo haver períodos ou fases em que os adolescentes identificam-se e vivenciam ora um fenômeno ora outro, com maior ou menor intensidade.

Luz: um raro produto de reação

The production of visible light by chemical reactions constitutes interesting and fascinating phenomena and several reaction mechanisms are discussed to rationalize excited state formation. Most efficient chemiluminescence reactions are thought to involve one or more electron transfer steps and chemiexcitation is believed to occur by radical annihilation. A brief introduction to the general principles of light production and the main known chemiexcitation mechanisms will be given here. Subsequently, recent results on the mechanistic elucidation of efficient chemiluminescence systems, as the peroxyoxalate reaction, the induced decomposition of phenoxy-substituted 1,2-dioxetanes and the catalyzed decomposition of new a-peroxylactones will be discussed.

Spin-Orbit Coupling in n-Type PbTe/PbEuTe Quantum Wells

Magnetoresistance measurements were performed on an n-type PbTe/PbEuTe quantum well and weak antilocalization effects were observed. This indicates the presence of spin orbit coupling phenomena and we showed that the Rashba effect is the main mechanism responsible for this spin orbit coupling. Using the model developed by Iordanskii et al., we fitted the experimental curves and obtained the inelastic and spin orbit scattering times. Thus we could compare the zero field energy spin-splitting predicted by the Rashba theory with the energy spin-splitting obtained from the analysis of the experimental curves. The final result confirms the theoretical prediction of strong Rashba effect on IV-VI based quantum wells.

Proposal of a High-Level Language for Writing Self Modifying Programs

This paper proposes a simple high-level programming language, endowed with resources that help encoding self-modifying programs. With this purpose, a conventional imperative language syntax (not explicitly stated in this paper) is incremented with special commands and statements forming an adaptive layer specially designed with focus on the dynamical changes to be applied to the code at run-time. The resulting language allows programmers to easily specify dynamic changes to their own program`s code. Such a language succeeds to allow programmers to effortless describe the dynamic logic of their adaptive applications. In this paper, we describe the most important aspects of the design and implementation of such a language. A small example is finally presented for illustration purposes.