Validation and application of the lattice Boltzmann algorithm for a turbulent immiscible Rayleigh-Taylor system.

We develop a multicomponent lattice Boltzmann (LB) model for the two-dimensional Rayleigh-Taylor turbulence with a Shan-Chen pseudopotential implemented on GPUs. In the immiscible case, this method is able to accurately overcome the inherent numerical complexity caused by the complicated structure of the interface that appears in the fully developed turbulent regime. The accuracy of the LB model is tested both for early and late stages of instability. For the developed turbulent motion, we analyse the balance between different terms describing variations of the kinetic and potential energies. Then we analyse the role of the interface in the energy balance and also the effects of the vorticity induced by the interface in the energy dissipation. Statistical properties are compared for miscible and immiscible flows. Our results can also be considered as a first validation step to extend the application of LB model to three-dimensional immiscible Rayleigh-Taylor turbulence. This article is part of the theme issue 'Progress in mesoscale methods for fluid dynamics simulation'.

Spiramyin-loaded PLGA implants for the treatment of ocular toxoplasmosis: development, characterization, biocompatibility, and anti-toxoplasma activity.

Ocular toxoplasmosis is the major cause of infectious posterior uveitis worldwide, inducing visual field defect and/or blindness. Despite the severity of this disease, an effective treatment is still lacking. In this study, spiramycin-loaded PLGA implants were developed aiming at the treatment of ocular toxoplasmosis. Implants were manufactured by a hot-molding technique, characterized by Fourier Transform Infrared Spectroscopy, X-Ray Diffraction, Differential Scanning Calorimetry, Scanning Electron Microscopy; evaluated in terms of ocular biocompatibility by immunofluorescence, flow cytometry, cell migration, Hen's egg test-chorioallantoic membrane (HET-CAM) irritation test; and investigated in terms of in vitro efficacy against Toxoplasma gondii . Characterization techniques indicated that spiramycin was dispersed into the polymeric chains and both substances preserved their physical structures in implants. The HET-CAM test indicated that implants did not induce hemorrhage or coagulation, being non-irritant to the CAM. ARPE-19 cells showed viability by MTT assay, and normality in cell cycle kinetics and morphology, without stimulating cell death by apoptosis. Finally, they were highly effective against intracellular parasites without inducing human retinal pigment epithelial cell death. In conclusion, spiramycin-loaded PLGA implants represent a promising therapeutic alternative for the local treatment of ocular toxoplasmosis.

Pathological gambling subtypes: A comparison of treatment-seeking and non-treatment-seeking samples from Brazil and Canada.

BACKGROUND: Pathological gambling (PG) is a heterogeneous disorder. The identification and characterization of PG subtypes could lead to tailored treatment approaches, which may, in turn, improve treatment outcomes. OBJECTIVE: To investigate PG subtypes based on personality traits across two different cultural and clinical settings. Consistent with the Pathways Model, we hypothesized the presence of three subtypes (behaviorally conditioned - BC, emotionally vulnerable - EV, and antisocial impulsivist - AI). METHODS: 140 PG adults from São Paulo, Brazil (SP sample) and 352 adults with PG (n=214) or sub-clinical PG (n=138) from Toronto, Canada (TO sample) completed the Temperament and Character Inventory (TCI). Latent-class analysis was used to investigate subtypes. RESULTS: A 2-class solution was the best model for the pooled SP and TO samples. Class 1 presented a normative personality profile and was composed exclusively of participants from Toronto (BC subtype). Class 2 was characterized by high novelty seeking, high harm avoidance, and low self-directedness, and included participants from both SP and TO (EV subtype). When sub-clinical PGs were excluded from the analysis, a single-class solution better characterized the SP and TO samples. CONCLUSIONS: Our results suggest that PG severity, rather than community or clinical settings, may have an effect on PG subtypes. The generalizability of the results is limited by the demographic and clinical features of the selected samples. Future neurobiological studies may contribute to the categorization of subjects into PG subtypes based on different underlying biological pathways.

Neural activity changes to emotional stimuli in healthy individuals under chronic use of clomipramine.

Previous functional magnetic resonance imaging (fMRI) studies examined neural activity responses to emotive stimuli in healthy individuals after acute/subacute administration of antidepressants. We now report the effects of repeated use of the antidepressant clomipramine on fMRI data acquired during presentation of emotion-provoking and neutral stimuli on healthy volunteers. A total of 12 volunteers were evaluated with fMRI after receiving low doses of clomipramine for 4 weeks and again after 4 weeks of washout. Fear-, happiness-, anger-provoking and neutral pictures from the International Affective Picture System (IAPS) were used. Data analysis was performed with statistical parametric mapping (P < 0.05). Paired t-test comparisons for each condition between medicated and unmedicated states showed, to negative valence paradigms, decrease in brain activity in the amygdala when participants were medicated. We also demonstrated, across both positive and negative valence paradigms, consistent decreases in brain activity in the medicated state in the anterior cingulate gyrus and insula. This is the first report of modulatory effects of repeated antidepressant use on the central representation of somatic states in response to emotions of both negative and positive valences in healthy individuals. Also, our results corroborate findings of antidepressant-induced temporolimbic activity changes to emotion-provoking stimuli obtained in studies of subjects treated acutely with such agents.

[Congenital epulis]. / Epulis congénito.

Congenital epulis or gingival granular cell tumor is an uncommon benign tumor, usually diagnosed at birth as a pediculated maxilar gingival mass. Although some cases of spontaneous regression have been described, most of the lesions are surgically removed with excelent prognosis and cosmetic final result. The authors describe a case report as well as a short revision on this pathology.

Under-report and underdiagnosis of chronic respiratory diseases in an African country.

BACKGROUND: Chronic respiratory diseases (CRD) are greatly underestimated. The aim of this study was to assess the burden associated with reported CRD and chronic obstructive pulmonary disease, as defined on the basis of various standardized criteria, by estimating their point prevalence in a sample of individuals attending the Primary Health Care (PHC) level and Emergency Room (ER) Departments in Cape Verde (CV) archipelago. The second aim of the study was to identify factors related to airways obstruction and reported CRD in this population. METHODS: A cross-sectional study was carried out in CV during 2 weeks. Outpatients aged more than 20 years seeking care at PHC level and ER answered a standardized questionnaire and were subjected to spirometry, independently of their complaint. Two criteria for airways obstruction were taken into account: forced expiratory volume (FEV(1)) <80% of the predicted value and FEV(1)/forced vital capacity (FVC) ratio <0.70. RESULTS: A total of 274 individuals with a satisfactory spirometry were included. 22% of the individuals had a FEV(1) < 80%. Individuals older than 46 years had a higher risk of having airways obstruction. Asthma diagnosis (11%) had a clear association with airways obstruction. Smoking was a risk factor for a lower FEV(1). Working in a dust place and cooking using an open fire were both related to chronic bronchitis and asthma diagnosis. CONCLUSION: Under-report and underdiagnosis of chronic respiratory conditions seem to be a reality in CV just as in other parts of the world. To improve diagnosis, our results reinforce the need of performing a spirometry.

[Pre-natal retroperitoneal mass: teratoma or fetus in fetu?]. / Masa prenatal retroperitoneal: teratoma o fetus in fetu?

BACKGROUND: Several case reports in the literature brought to discussion the distinction criteria between fetus in fetu and teratoma. CASE REPORT: The authors present a case report of a premature newborn boy, evaluated for a capsulated abdominal mass with prenatal diagnosis pointing to possible malignant lesion. A CT scan showed an expansive, retroperitoneal lesion, from kidneys to pelvis, sacrum and coccyx, with solid, cystic and fatty areas; the fine needle aspiration was inconclusive, and he underwent surgery on day 9 with partial resection of the lesion. A new procedure to complete the excision was performed 8 months later. The histopathologic examination of the two fragments showed mature and organized components of nervous system, respiratory and digestive apparatus (liver and pancreas included), thymus, nervous ganglia, skin and adnexa, musculoskeletal and brown adipose tissues; cartilage and several focus of calcification. These components showed a craniocaudal orientation, but no evidence of organoid formation. DISCUSSION: This case presents features of both teratoma and fetus in fetu. The assumption of either one of the diagnosis has prognostic implications, with resulting differences in clinical follow up and expectations about the child's health.

Masa prenatal retroperitoneal: ¿teratoma o fetus in fetu? / Pre-natal retroperitoneal mass: teratoma or fetus in fetu?

Introdución. Varios artículos de la literatura médica han hecho cobrar vigencia la discusión sobre criterios de distinción entre fetus infetu y teratoma. Caso clínico. Se presenta un caso de un recién nacido prematuro, evaluado por demostrar una masa abdominal encapsulada con signos de malignidad, que había sido diagnosticada en el período prenatal. La exploración de TAC demostró una lesión expansiva, retroperitoneal, que abarcaba de riñones a pelvis, sacro y cóccix, con áreas sólidas, quísticas y de grasa; la biopsia por aspiración con aguja fina era no concluyente, y se procedió a intervención en el noveno día de vida, con la resección parcial de la lesión. Un nuevo procedimiento para completarla exéresis de la masa fue realizado a los 8 meses. El examen histopatológico demostró componentes maduros y organizados del sistema nervioso, aparato respiratorio y digestivo (hígado y páncreas incluidos),timo, tejido adiposo marrón, ganglios del sistema nervioso autónomo, piel y anejos cutáneos, tejido muscular liso y estriado, cartílago y varios focos de calcificación. Estos componentes demostraban una orientación cráneo-caudal, pero no formaban órganos distintos. Discusión. Este caso presenta características de teratoma y fetus infetu. La asunción de cualquiera de los diagnósticos tiene implicaciones pronosticas, originando diferencias en el seguimiento médico y en las expectativas clínicas sobre la salud de niño (AU)

Background. Several case reports in the literature brought to discussion the distinction criteria between fetus in fetu and teratoma. Case report. The authors present a case report of a premature newborn boy, evaluated for a capsulated abdominal mass with prenatal diagnosis pointing to possible malignant lesion. A CT scan showed an expansive, retroperitoneal lesion, from kidneys to pelvis, sacrum and coccyx, with solid, cystic and fatty areas; the fine needle aspiration was inconclusive, and he underwent surgery on day 9 with partial resection of the lesion. A new procedure to complete the excision was performed 8months later. The histopathology examination of the two fragments showed mature and organized components of nervous system, respiratory and digestive apparatus (liver and pancreas included), thymus, nervous ganglia, skin and adnexa, musculoskeletal and brown adipose tissues; cartilage and several focus of calcification. These components showed a craniocaudal orientation, but no evidence of organoid formation. Discussion. This case presents features of both teratoma and fetus in fetu. The assumption of either one of the diagnosis has prognostic implications, with resulting differences in clinical follow up and expectations about the child’s health (AU)

Febrile convulsions in developing rats induce a hyperanxious phenotype later in life.

Exposure of rodent pups to hyperthermia constitutes one of the best known models of febrile seizures. Studies designed to evaluate the behavioral impact of heat-induced convulsions (HCs) have focused mainly on hippocampus-dependent tasks and produced rather conflicting results. In this study, we assessed, in detail, developmental milestones, emotional behavior, and cognitive performance in animals submitted to HCs on Postnatal Day 10. There was no alteration in the acquisition of neurological reflexes, but there was an anticipation of eye opening in animals exposed to hyperthermia. As adults, the locomotor and exploratory behavior of these rats was unaffected. Interestingly, animals exposed to hyperthermia displayed signs of increased anxiety in the elevated-plus maze, although these signs were not associated with increased susceptibility to depression-like behavior. Additionally, we failed to observe impairments in spatial and working memory tasks. In conclusion, HCs at a particular period of neurodevelopment determine a hyperanxious phenotype later in life.

Gender differences in gambling progression.

The authors compared 39 women and 38 men entering an outpatient treatment program for pathological gambling. They were diagnosed according to DSM-IV and selected by SOGS, followed by a semi-structured interview for demography and progression of the gambling behavior prior to treatment. Women were more often single (59% vs. 26%; p = .005) and started gambling significantly later than men (34.2 vs. 20.4 years; p < .001). The progression of the disorder was more than 2 times faster in women than in men. There was no difference in the age of seeking treatment (44.7 vs. 42.3 years). Findings from this study resemble gender differences in other addictions--in particular the faster progression among women--challenge pharmacodynamic hypotheses for this phenomenon, and suggest gender into account when devising treatment strategies for pathological gambling.

Tinea cruris epidemiology (São Paulo, Brazil).

In order to determine the epidemiology of tinea cruris in São Paulo, Brazil, an investigation was carried out from April 95 to March 1997. A total of 2000 individuals were studied, of whom 105 were suspected of having tinea cruris infection. Direct microscopy and/or culture were positive in 66 [62.8%] of the cases. Erythematous-scale plaques and erythematous-liquenificated plaques were the most frequently found clinical types. T. rubrum was the prevalent dermatophyte in 90% of the cases, followed by T. tonsurans (6%) and T. mentagrophytes (4%).

Assessment of medical courses in Brazil using student-completed questionnaires. Is it reliable?

INTRODUCTION: Debates about the quality of medical education have become more evident in the recent past, and as a result several different assessment methods have been refined for that purpose. The use of questionnaires filled out by medical students to assess the quality of lectures is one of the most common methods employed in our milieu. However, the reliability of this investigation method has not yet been systematically tested. The authors present the reliability of a specific form applied to the fourth grade medical students during the clinical psychiatry course. METHOD: Eighty-one fourth grade medical students were instructed to complete a form immediately after each clinical psychiatry lecture. Thirty-four students (42%) failed to turn in the forms after the final lecture. These students were given an identical form to assess the lectures in a retrospective fashion. The grades given by both groups of students for each performed lecture and the number of students who have graded an unperformed lecture were compared. Statistical significance for both groups was determined by means of the chi-square test (p< 0.05). RESULTS: Eighteen out of the 34 students who filled out the forms retrospectively (53%) rated the unperformed lecture, whereas only 5 out of the 47 students who filled out the forms during the course (11%) did so. This is statistically significant (p< 0.05). There was no statistical difference for the grades given to the lectures that were actually performed. DISCUSSION: The authors concluded the low reliability rate of the retrospective evaluation warrant a continuous assessment method during the course.

Dynamics of some limnological characteristics in pacu (Piaractus mesopotamicus) culture tanks as function of handling.

In order to study the water quality in fish tanks, a 166-day (January to July 1992) experiment was realized using the indigenous species "p acu" (Piaractus mesopotamicus). Two different protein levels were tested in the diet (16% and 34% crude protein) and three stocking densities (0.25, 0.50 and 0.77 fish/m2). From the results, it was observed that the interactions between stocking density and experiment length affected the characteristics bicarbonate and alkalinity, as well as the interaction between stocking density and protein levels affected concentrations of free and total CO2, conductivity and pH (P < 0.05). The water temperature in tanks changed significantly during the period of study (P < 0.05),decreasing gradually from summer to winter. There was no significant difference in water residence time in the tanks (P < 0.05) during the experiment. The other limnological characteristics were not affected by treatments during study period.

Atmospheric metal pollution (Cr, Cu, Fe, Mn, Ni, Pb and Zn) in Oporto city derived from results for low-volume aerosol samplers and for the moss Sphagnum auriculatum bioindicator.

A low-volume aerosol sampler with filters and bags of Sphagnum auriculatum were exposed, in parallel, to the atmosphere of Oporto city for approx. 2 months in 1994, during a dry weather period. The levels of Cr, Cu, Fe, Mn, Ni, Pb and Zn in the moss (weekly samples) and in the filters (daily samples) were determined by atomic absorption spectrophotometry and the results were compared. For all the heavy metals, the rate of metal uptake by moss was significantly correlated with the metal concentration in atmospheric aerosols. The results indicated that moss bags of S. auriculatum can provide a quantitative estimation of the concentration of different heavy metals in urban atmospheres, when specific calibration by mechanic monitoring, at the same sampling point, is performed during a first stage of biomonitoring. The mean aerosol metal concentrations found in the Oporto atmosphere were similar to those observed in other urban atmospheres in different countries. The relative order of the mean metal concentrations was Fe (1.8 micrograms/m3) > Zn > Pb > Cu > Cr > Mn > Ni (20 ng/m3). The aerosol Pb levels were monitored at different sampling points over various periods of time between 1991 and 1997. The mean Pb levels were < or = 0.5 microgram/m3 and approximately constant at each sample point up to January 1996. After that date it decreased by approx. 50%, in consequence of the reduction of the Pb concentration in leaded gasoline.

Trace element concentrations in blood and hair of young apprentices of a technical-professional school.

The concentrations of total Fe, Cu, Mn, Zn, Pb, Cr, Ni and Ca in the whole blood of young male apprentices of a technical-professional school, who are exposed to low doses of fumes from manual metal arc welding of mild steel, were monitored over their 2 years of apprenticeship in order to evaluate the influence of occupational exposure on biological metal levels. The results were compared with those from a control group of the same sex and age and living in the same geographic area. For comparison, monitoring of the same metal levels in the hair of both groups of individuals were also carried out. In the apprentices, the mean metal concentrations in blood at the end of the study were statistically significantly higher for Cu, lower for Fe and Mn and similar for the remaining metals. The levels of Fe significantly decreased whereas the levels of Cu were significantly increased during the study. A systematic influence of the exposure period on the levels of Mn was not observed. All the metal concentrations measured in the blood and hair of both apprentices and controls fell in the very large range of published reference levels. Seasonal variation (higher levels in the summer) of the hair metal concentrations were observed for Mn, Cu, Pb, Ni, Zn and Ca.

Esophageal involvement in congenital Chagas' disease. Report of a case with megaesophagus.

A full-term infant developed dysphagia, vomiting, and regurgitation immediately after birth. On examination at 5 months of age, he was malnourished and had radiographically proven megaesophagus. On direct examination his blood was positive for Trypanosoma cruzi. Additionally an enzyme immunoassay for T. cruzi IgM antibodies was positive. He underwent corrective surgery for the megaesophagus but died post-operatively of aspiration pneumonia. At autopsy, the esophagus was markedly dilated. There was an extreme reduction of neurons in Auerbach's plexus, and inflammation of this plexus and the muscular layer of the esophagus. Nests of parasites were seen in the esophagus and bladder. It is suggested that this patient was not in the chronic phase of Chagas' disease but represents an acute digestive phase of this infection. This is the fourth case in the literature of congenital Chagas' disease with esophageal involvement and clinical signs, and the first in which megaesophagus was seen grossly at post-mortem examination.