Effect of Interfacial SiOx Defects on the Functional Properties of Si-Transition Metal Oxide Photoanodes for Water Splitting.

The transfer of photogenerated charges through interfaces in heterojunction photoanodes is a key process that controls the efficiency of solar water splitting. Considering Co3O4/SiOx/Si photoanodes prepared by physical vapor deposition as a representative case study, it is shown that defects normally present in the native SiOx layer dramatically affect the onset of the photocurrent. Electron paramagnetic resonance indicates that the signal of defects located in dangling bonds of trivalent Si atoms at the Si/SiOx interface vanishes upon vacuum annealing at 850 °C. Correspondingly, the photovoltage of the photoanode increases to ≈500 mV. Similar results are obtained for NiO/SiOx/Si photoanodes. Photoelectrochemical analysis and impedance spectroscopy (in solution and in the solid state) indicate how the defect annealing modifies the Co3O4/SiOx/Si junction. This work shows that defect annealing at the solid-solid interface in composite photoanodes strongly improves the efficiency of charge transfer through interfaces, which is the basis for effective solar-to-chemical energy conversion.

Automedicación en adolescentes universitarios / Self medication among university adolescents

El objetivo de este trabajo fue conocer el autoconsumo de medicamentos en alumnos menores de 20 años, ingresantes al 1er. año de la carrera de medicina. Sobre un total de 2049 alumnos ingresantes en forma directa (año 1996), fueron encuestados 330 en forma voluntaria. El cuestionario contenía 52 preguntas abiertas y cerradas y recababa datos identificatorios, socieconómicos, culturales y relacionados con el consumo y conocimiento de medicamentos. Se obtuvo entre los resultados: que de los 330 encuestados, 300 son menores de 20 años y 102 de ellos declaran automedicarse. De éstos (56 por ciento sexo femenino y 44 por ciento sexo masculino) y el 30 por ciento admitió haber obtenido información para hacerlo de médicos, el 22 por ciento de algún familiar y el 18 por ciento del farmacéutico. Reconocen efectos colaterales y contraindicaciones. Los medicamentos más frecuentemente utilizados son: analgésicos (90 por ciento), antibíoticos (22 por ciento), y vitaminas (17 por ciento), obteniéndolos en farmacias (87 por ciento), en laboratorios de productos medicinales (25 por ciento) y en kioscos (18 por ciento). El 29 por ciento de los encuestados declara, además, consumir medicamentos caseros. Se concluyó que, siendo una población joven, un alto porcentaje de alumnos consume medicamentos y sobre todo sin prescripción médica, a pesar de que la mayoría de los mismos son de venta bajo receta, así como resultó llamativo el reconocimiento de efectos colaterales y contraindicaciones y sin embargo la escasa gravedad que los alumnos le otorgan a los mismos (AU)

Automedicación en adolescentes universitarios / Self medication among university adolescents

El objetivo de este trabajo fue conocer el autoconsumo de medicamentos en alumnos menores de 20 años, ingresantes al 1er. año de la carrera de medicina. Sobre un total de 2049 alumnos ingresantes en forma directa (año 1996), fueron encuestados 330 en forma voluntaria. El cuestionario contenía 52 preguntas abiertas y cerradas y recababa datos identificatorios, socieconómicos, culturales y relacionados con el consumo y conocimiento de medicamentos. Se obtuvo entre los resultados: que de los 330 encuestados, 300 son menores de 20 años y 102 de ellos declaran automedicarse. De éstos (56 por ciento sexo femenino y 44 por ciento sexo masculino) y el 30 por ciento admitió haber obtenido información para hacerlo de médicos, el 22 por ciento de algún familiar y el 18 por ciento del farmacéutico. Reconocen efectos colaterales y contraindicaciones. Los medicamentos más frecuentemente utilizados son: analgésicos (90 por ciento), antibíoticos (22 por ciento), y vitaminas (17 por ciento), obteniéndolos en farmacias (87 por ciento), en laboratorios de productos medicinales (25 por ciento) y en kioscos (18 por ciento). El 29 por ciento de los encuestados declara, además, consumir medicamentos caseros. Se concluyó que, siendo una población joven, un alto porcentaje de alumnos consume medicamentos y sobre todo sin prescripción médica, a pesar de que la mayoría de los mismos son de venta bajo receta, así como resultó llamativo el reconocimiento de efectos colaterales y contraindicaciones y sin embargo la escasa gravedad que los alumnos le otorgan a los mismos

[Adiposity and fat distribution in preschool children from low socioeconomic levels in Caracas]. / Adiposidad y patrón de distribución en un grupo de preescolares de estratos socioeconómicos bajos de Caracas.

Epidemiological studies suggest that body fat distribution in adults is associated with chronical nontransmissible diseases, less is known during the growing years. The current study was undertaken to explore the relationship between level of fatness, fat patterning and some socioenvironmental variables in a group of 449 children aged 3 to 6, living in Caracas, who belong to the poorest Venezuelan socio-economic stratum. Data was analyzed taking nutritional status (weight-for-age), an index of socioeconomic conditions (ICSA), sex and age, as control variables. Using a multivariate analysis we derived first, two groups of households (G1 and G2) as determined by socioeconomic variables, to which principal component analysis was applied to elicited fatness and relative fat patterning through six skinfolds. First component identify level of adiposity, second extremity/trunk fatness, and third upper/lower pattern. Comparison of normal children with those of low weight-for-age showed differences in adiposity and in the upper/lower patterning as detected by the skinfolds involved in the differences: subscapular (-0.53) and supraspinale (0.32) in children with low weight-for-age; triceps (-0.46) and thigh (0.29) in those classified as normal. We found that gender, nutritional condition, environmental variables and age, were significant predictors of the differences in adiposity level; while age and households conditions, appear to be related to upper/lower patterning. The data equally suggests that body fat is more centrally distributed in boys with low weight-for-age. Since these patterns are indicators of risk in the ongoing years, we call tha attention about environmental circumstances.

Son utiles los antimicrobianos de accion local en la diarrea prolongada con sobrecrecimiento bacteriano en liquido duodenal? / Are the local antimicrobials action useful in prolonged diarrhea with bacterial overgrowth in duodenal content?

Para evaluar la utilidad de dos antibioticos de accion local en ninos con diarrea prolongada y sobrecrecimiento bacteriano en liquido duodenal (SBLD) se estudiaron 22 pacientes que fueron divididos en tres grupos: ocho recibieron colimicina, seis furazolidona y ocho ningun antimicrobiano.Despues del tratamiento, se negativizaron seis cultivos duodenales con colimicina (75%), cuatro con furazolidona (66%) y siete sin antibiotico (87.5%) (p > 0.05), remitiendo la diarrea a los 4.0, 4.5 y 3.0 dias respectivamente (p > 0.05). No se detecto septicemia en los pacientes sin antimicrobiano, mientras que esta se presento en uno que recibio furazolidona y en dos con colimicina (p > 0.05). No encontramos utilidad en el tratamiento con furazolidona o colimicina y es probable que exista un mayor riesgo de complicaciones infecciosas. Se estudiaron ademas los posibles mecanismos de patogenicidad en las bacterias aisladas

Pseudotruncus arteriosus: Its occurrence with acquired aortic stenosis in an adult.

Prolonged survival with pseudotruncus arteriosus, an extreme variant of Fallot's tetralogy, is unusual. We studied the clinical and pathological findings in an adult with uncorrected pseudotruncus. Longevity may have been related to the presence of markedly enlarged bronchial arteries that provided collateral circulation to the lungs. However, prolonged survival was accompanied by the development of severe degenerative changes of the aortic valve leaflets that resulted in acquired valvular stenosis.

Effects of irradiation on mixed müllerian tumors of the uterus.

A retrospective study of 54 patients with histologically proven malignant mixed müllerian tumors of the uterus was undertaken with main emphasis on the evaluation of the effects of irradiation on pelvic tumor control. The tumors were staged according to the FIGO classification for endometrial carcinoma and 24 were classified as Stage I, 10 as Stage II, 13 as Stage III and seven as Stage IV. Patients with Stage I and II were treated with surgery alone (9 patients, three surviving) or preoperative intracavitary irradiation (13 patients, eight surviving) or preoperative combination of intracavitary and external irradiation (12 patients, six surviving). Five patients with Stage III and IV were treated with surgery alone, two were treated with a combination of irradiation and surgery and 11 with radiation alone. None of these patients survived. In seven patients showing no residual tumor in the uterine specimen after irradiation, no pelvic failures were noted, whereas seven of 17 (41.2%) with residual tumor developed pelvic recurrences. In patients with Stage I treated with surgery alone, three out of six recurred in the pelvis whereas only three of 17 (17%) receiving preoperative irradiation developed pelvic recurrences. However, in Stage II six of eight patients treated with preoperative irradiation failed in the pelvis. Correlation with the doses of irradiation given to the uterus or the pelvic lymph nodes indicate that with doses below 5000 rads a significantly higher number of pelvic recurrences take place, whereas these are uncommon with doses over 6000 rads. The difference in pelvic recurrences between dosage levels is not, however, statistically significant. It is suggested that patients with Stage I and II malignant mixed müllerian tumors of the uterus should be treated with preoperative radiation and total hysterectomy with bilateral salpingo-oophorectomy. Patients with more advanced disease have extremely poor prognosis and should be treated with radiation therapy alone. This tumor has a high propensity to spread through lymphatics and hematogenous metastases are seen in approximately 75% of the patients. Because of this dissemination, significant improvements in survival rate will not be seen until effective cytotoxic agents are available.

Primary mucinous carcinoma of the skin.

Only twenty-seven cases of primary mucinous carcinoma of the skin have been reported. Three additional cases are included in this paper. The clinical presentation is distinctive; they are found most commonly in middle-aged, black males in the head and neck region as painless nodules, usually less than 3 cm in diameter. Previous reports have indicated the probable sweat gland origin of these tumours; one of our cases demonstrates a transition from a solid hidradenoma-like pattern to nests of tumour cells floating in mucin lakes, adding support for the sweat gland hypothesis. The clinical behaviour is relatively benign; late recurrences are common but metastases are rare. Only one case had widespread metastases. Although the histological appearance is distinctive, other primary sites first must be excluded. Local excision is the treatment of choice.