Thermal annealing and electrochemical purification of multi-walled carbon nanotubes produced by camphor/ferrocene mixtures.

Multi-walled carbon nanotubes (MWCNT) were obtained by pyrolysis of camphor/ferrocene mixtures, at different concentrations of ferrocene, on quartz, polished silicon and carbon felt substrates. A detailed study by electron microscopy, Raman spectroscopy, X-ray diffraction and thermogravimetric analysis was carried out to determine the purity degree of MWCNTs. Thermal annealing under vacuum and electrochemical purification were used for iron removal. The thermal annealing brings improvement on crystalline structure of MWCNTs, besides iron elimination from internal structure of the tubes, while the electrochemical treatments remove efficiently the iron from MWCNT surface.

Unerupted second primary mandibular molar positioned inferior to the second premolar: case report.

This report is a clinical case of a 7-year-old child who presented right impacted second primary mandibular molar. This tooth was positioned inferior to the second premolar successor and a supernumerary tooth superior to the second premolar. Clinical examination did not reveal systemic diseases ot trauma in the facial region. Treatment consisted of the extraction of the impacted second primary molar and the supernumerary tooth. Periodic examination was indicated for follow-up.

Stereological study of the sexual dimorphism in mouse submandibular glands.

The sexual dimorphism of the mouse submandibular glands was studied by stereological methods. Albino mice of both sexes aged 140 days were used. Their average weight was 34.7 g por males and 26.0 g for females. The following morphometric dimensions were evaluated for the acini, intercalated ducts, convoluted granular tubules, striated ducts, excretory ducts and stroma: volume density, total volume, surface density, total external surface, surface-to-volume ratio, nuclear and cellular volume, and absolute number of cells. We also determined the mean diameters and estimated the total length of striated ducts and granular tubules in the gland. Analysis of the results showed that sexual dimorphism is present in all the morphological compartments of the mouse submandibular glands.

Contamination of dental radiographic solutions.

Thirteen groups of periapical radiographic films were evaluated to determine and compare within and between groups the effects of contamination of the fixer solution with developing solution during radiographic processing. An aluminum penetrometer was used as the radiographic object to produce different optical densities. The images were compared using radiographic density and contrast as parameters. There were significant differences between the control groups and the groups processed with a contaminated fixer solution. No statistically significant differences were observed in the intragroup comparisons.

[Analysis of teaching practices of university professors in the health field]. / Uma análise das práticas docentes de professores universitários da área de saúde.

The study aims to describe teaching practices--in planning, execution and evaluation of the teaching-learning process--used by faculty of some courses in the health field in Brazil: Odontology, Medicine, Nursing, Pharmacy, Psychology, Nutrition, Social Work and Veterinary Medicine. The sample was made up by 29 faculties enrolled in a didactic subject course at graduate programs. They answered a questionnaire with semi-open questions. The answers obtained point to a "banking" education practice, according to Paulo Freire. This kind of education is characterized by: 1) emphasis on the transmission of information; 2) many hours of education; 3) little integration between courses and 4) lecture classes.

[Hemangioendothelioma of the lip]. / Hemangioendotelioma do lábio.

Hemangioendothelioma is a relatively uncommon tumor of the oral cavity. This article reviews the literature on hemangioendothelioma and presents one additional case of this neoplasm found on the lip.