Síntese e estudo de ortossilicatos de zinco luminescentes com aplicação da técnica sol-gel

Usually, the concepts of the Sol-Gel technique are not applied in experimental chemistry courses. This work presents a feasible experiment for chemistry instruction, which involves the synthesis of luminescent materials - Zn2SiO4, with and without Mn2+ as a dopant - by the Sol-Gel technique. The obtained materials were analyzed by scanning electron microscopy, X-Ray diffraction, IR spectroscopy and luminescence measures by UV-vis spectroscopy. The results allow the students to confirm the luminescent properties of the zinc orthosilicate luminophores as well as the structural features expected from literature data.

Estudo por espectroscopia micro-Raman dos mecanismos de separação de fase em vidros fosfatos de metais de transição

Glass-ceramics are prepared by controlled separation of crystal phases in glasses, leading to uniform and dense grain structures. On the other hand, chemical leaching of soluble crystal phases yields porous glass-ceramics with important applications. Here, glass/ceramic interfaces of niobo-, vanado- and titano-phosphate glasses were studied by micro-Raman spectroscopy, whose spatial resolution revealed the multiphase structures. Phase-separation mechanisms were also determined by this technique, revealing that interface composition remained unchanged as the crystallization front advanced for niobo- and vanadophosphate glasses (interface-controlled crystallization). For titanophosphate glasses, phase composition changed continuously with time up to the equilibrium composition, indicating a spinodal-type phase separation.

Aplicações de cromatografia líquida de alta eficiência para o estudo de poluentes orgânicos emergentes

Emerging organic pollutants (EOP) include many environmental contaminants based on commercial products such as pharmaceuticals, personal care products, detergents, gasoline, polymers, etc. EOP may be candidates for future regulation as they offer potential risk to environmental and human health due to their continual entrance into the environment and to the fact that even the most modern wastewater treatment plants are not able to totally transform / remove these compounds. High performance liquid chromatography is recommended to separate emerging organic pollutants with characteristics of high polarity and low volatility, especially pharmaceuticals, from environmental matrices.

Estudo químico de Sinningia allagophylla guiado por testes de atividade antiproliferativa

Activity guided fractionation of Sinningia allagophylla (Mart.) Wiehler ethanolic extract yielded a new benzochromene 8-methoxylapachenol, besides seven known compounds: lapachenol, sitosteryl oleate, sitosteryl linoleate, stigmasteryl oleate, stigmasteryl linoleate, dunniol and tectoquinone. Extract, fractions, and compounds lapachenol, 8-methoxylapachenol, and dunniol were tested in vitro against human cancer cell lines U251 (glioma, CNS), MCF-7 (breast), NCI-ADR/RES (drug-resistant ovarian), 786-0 (kidney), NCI-H460 (lung, no small cells), PC-3 (prostate), OVCAR-3 (ovarian), HT-29 (colon), K562 (leukemia) and against VERO, a normal cell line. The most active compound was dunniol, which inhibited the growth of U251, MCF-7, NCI-ADR/RES, OVCAR-3 and K562 cell lines.

Avaliação física do tomate de mesa 'Romana' durante manuseio na pós-colheita

Tomato postharvest losses are very high in Brazil and the goal of this research was to evaluate the effect of handling and the transport of tomato fruits, cultivar Romana on the steps of harvesting, weight and transportation to the packinghouse, pointing some critical points. Tomatoes were harvested at plastic boxes, weighted and shipped to a packinghouse. Fruits taken directly from the plant were determined as reference. The parameters evaluated were weight loss and mechanical injury and tomato physical quality after storage during 21 days. It was observed an increasing on the weight loss, external damage, and postharvest losses, after storage. Handling and transportation were the cause of an increase in 6.6% in external damage and 1.93% of weight loss after storage, when comparing harvested fruits and fruits evaluated on the packing-house. The main reason for postharvest losses was due to mechanical injury caused during transportation mainly due to the compressure force among fruits and against the plastic boxes.

Proposta de mecanismo de lavagem em equipamentos de beneficiamento de tomate de mesa

The cleanness level in fresh market tomatoes cleaning equipment is essential for consumer acceptance and conservation of product quality. However, the washing process in cleaning current equipments demands an excessive volume of water, leading to serious economic and environmental concerns. The objective of this work was to contribute with technical information for the washing system optimization. The conventional washing system currently used in cleaning equipment, which consists of perforated PVC pipes, was compared with a proposed system which uses commercial sprays. Characteristic curves (flow rate versus pressure) for both systems were determined in lab conditions and the respective water consumptions were compared. The results confirmed the excess of water consumption in the conventional washing systems, and the proposed system proved that is possible to reduce it, and the use of sprays allowed the rational use of the water.

Qualidade da classificação do tomate de mesa em unidades de beneficiamento

Quality evaluation of classification was done in two fresh market tomatoes packing house, using electronically and mechanical equipments in two harvest periods, summer and winter seasons. The main goal of this work was to evaluate size and color grading conformity with the standards proposed by the Brazilian Program for Horticulture Modernization and size grading obtainded with the one established by the packer. The cultivar studied was Carmen. The results showed that there was no grade conformity with the fresh tomato quality standards proposed by the Brazilian Program for Horticulture Modernization. The grade conformity obtained when compared with the one programmed by the packer, was only for large sizes, in both equipments. The electronically equipment has presented better performance, over the mechanical, considering grading quality and fruits post-harvest quality. However, the electronically equipment must be constantly monitored to achieve efficiency and investment return. On the other side, for mechanical equipment it will be necessary to review the actual system of size grading, in order to follow the fresh tomato quality standards.

Caracterização de dois equipamentos de beneficiamento e classificação de tomates para mesa

On the last years, in Brazil, sorting and classifying fruits and vegetables using packing lines have increased. This work aimed at characterizing the cleaning process for fresh market tomatoes at two packing lines, one imported and one national located at Campinas, São Paulo State. Characterization included data, number, types and brushes velocity, water use, fruit standing time and cleaning efficiency. Standing time was measured correlating to fruit diameter (CEAGESP). For measuring cleaning efficiency an equipment was developed that was mainly composed of a ring involved with white cloth. Samples were taken before and after the cleaning step and evaluated using a colorimeter HUNTER Lab. The results showed a strong difference between the two equipments. The imported equipment showed lower number on brushes and rotation than national one, however a higher water consumption. For imported equipments this relation was not found. Both packing lines showed the same cleaning efficiency. Cleaning efficiency is related to be an interaction among the studies parameters, and it could be necessary a better management than the one used on both equipments.

Otimização da eficiência de limpeza em equipamento de beneficiamento de tomate de mesa

The post-harvesting cleaning process in fresh market tomatoes production is essential to the consumer acceptance, since the degree of dirtiness of the fruits is directly related to its quality. However, the washing stage of the cleaning process of commercial packinghouse demands an excessive water volume, bringing serious environmental concerns. The objective of this work was to compare the cleaning efficiency in two cleaning systems through the evaluation of different operational conditions of the cleaning process, related with the brush rotation, water flow and fruit standing time under the system. It was compared the conventional system utilized in commercial equipment with a system using commercial sprays. The results showed that the cleaning efficiency was not directly related to the water volume used, but to the water pressure, standing time and brushes rotation. Therefore, the use of commercial sprays can bring benefits to the cleaning efficiency, increasing it up to 13%, and to the environmental, decreasing water consumption.

Saúde dos adolescentes: um estudo de base populacional em Campinas, São Paulo, Brasil

We estimated the prevalence of chronic diseases and other health problems reported by adolescents in relation to social and demographic variables and nutritional status. This cross-sectional population-based survey analyzed data from the Health Survey in Campinas, São Paulo State, Brazil, 2008. We used descriptive statistics and associations between variables with the chisquare test. Prevalence of chronic diseases among adolescents was 19.17%, with asthma showing the highest prevalence (7.59%), followed by heart disease (1.96%), hypertension (1.07%), and diabetes 0.21%. Prevalence rates were 61.53% for health problems, 40.39% for allergy, and 24.83% for frequent headache or migraine. After multivariate analysis using Poisson regression, the factors associated with chronic disease were age 15 to 19 years (PR = 1.38), not attending school (PR = 1.46), having children (PR = 1.84), and obesity (PR = 1.54). Female gender (PR = 1.12) was statistically associated with health problems. The study illustrates that adolescence is a life stage in which chronic disease and health problems can occur.

Estudo inicial da degradação in vivo de poli(L-co-D,L ácido lático), sintetizado em laboratório, aplicado como prótese tibial em coelhos

The copolymer poly (L-co-D,L lactic acid), PLDLA, has gained prominence in the field of temporary prostheses due to the fact that their time of degradation is quite compatible with the requirement in the case of osseous fracture. In this work the in vivo degradation of devices from copolymer, as a system of plates and screws, used in fixation of the tibia of rabbits was studied. The devices were implanted in 15 adult rabbits, albinos, New Zealand race, and they were used as control devices of alloys of titanium (Ti-6Al-4V/ V grade). The use of copolymers, synthesized in the laboratory, was tested in the repair of fracture in rabbits'tibias, being assessed in the following times: 2 weeks, 2 months and 3 months. Morphological analysis of tissue surrounding the plate and screw system, for 2 weeks of implantation, showed the presence of osteoblasts, indicating a pre bone formation. After 2 months there was new bone formation in the region in contact with the polymer. This bone growth occurred simultaneously with the process of PLDLA degradation, invading the region where there was polymer and after 3 months there was an intense degradation of the copolymer and hence greater tissue invasion compared to 2 months which characterized bone formation in a region where the polymer degraded. The in vivo degradation study of the devices for PLDLA by means of histological evaluations during the period of consolidation of the fracture showed the efficiency of plate and screw system, and it was possible to check formation of bone tissue at the implantation site, without the presence of inflammatory reaction

Efeito cariostático de restaurações adesivas em superfícies radiculares: estudo in vitro

Dental materials that release fluoride have been shown to be effective in caries inhibition around restorations. Adhesive materials would also be effective in caries inhibition by sealing and protecting cavity margins from acidic demineralization. This in vitro study tested the hypothesis that composite restorations with a dentin adhesive system have a caries preventive effect similar to that of an adhesive material with fluoride - glass-ionomer cement - on root surfaces. Twenty roots from extracted sound third molars were embedded in polystyrene resin and ground flat. Standardized cavities were prepared in leveled root surfaces and randomly restored with (a) Chelon-Fil (Espe) or (b) Z100/SingleBond (3M). Baseline indentations were measured at 100, 200 and 300 mum from the occlusal margins of each restoration and the surface microhardness values were obtained using a Knoop diamond indenter. A 2.0 mm wide margin around the restorations was submitted to a pH-cycling model, at 37ºC. After that, surface microhardness was measured again, as it was before. The differences between baseline and final surface microhardness were considered for statistical analysis. The median values of differences were (a): -3.8; -0.3; -1.0; and (b): 3.3; 2.5; 1.7, for the distances of 100, 200 and 300 mum, respectively. The Kruskal-Wallis test did not show statistically significant difference between 100, 200 and 300 mum distances in each tested group. There was no difference between the studied materials at the distances of 200 and 300 mum. Chelon-Fil was statistically different from Z100/SingleBond, at 100 mum (p<0.05). Under the studied conditions, the glass-ionomer cement had a higher caries preventive effect than the composite/dentin adhesive restorations.

Estudo comparativo dos métodos de estimativa da idade óssea de Greulich & Pyle e Tanner & Whitehouse

The purpose of this study was to verify whether the Greulich & Pyle (GP), Greulich & Pyle Visual (GPV) and Tanner & Whitehouse (TW) methods for estimating skeletal age could be applied in the Brazilian population, and which of these three methods could be considered more reliable when compared with the chronological age of the individuals. This study was based on one hundred and sixty volunteers (80 females and 80 males) with ages between 6 years and 10 months and 14 years and 9 months. The results showed that for the GP method, the correlations with chronological age were 0.95 for males and 0.97 for females. For the GPV method, the correlations were 0.96 and 0.97, respectively and for TW, 0.96 and 0.97. The results showed that the Greulich & Pyle, Greulich & Pyle Visual and Tanner & Whitehouse methods presented high correlation values when compared with the chronological age of the individuals. Corrective factors were established to make these methods applicable to the Brazilian population.

Efeito de baixas doses de radiação X em feridas suturadas e não suturadas - estudo experimental em ratos

The present work evaluated the effect of low doses of X-irradiation on the repairing process of sutured and nonsutured skin wounds in rats. For that, rats underwent a surgical proceedure, in which a 20 x 5-millimeter rectangular wound approximately 2-millimeter-deep was made in the dorsal region of each animal, and were divided in four groups: nonirradiated nonsutured; irradiated nonsutured ; nonirradiated sutured and irradiated sutured. The animals under irradiation were protected, during exposure, with a 2-millimeter-thick lead apron in such a way that only the incision was irradiated. Each animal was submitted to 18 seconds of exposure, undergoing a total of 7.4 rads. The evaluation of the effects of X-rays on the repairing process was carried out through microscopic observation by means of hematoxylin-eosin staining for morphological evaluation, and silver impregnation under polarized light for the observation of collagen synthesis. The results have shown that X-irradiation has caused delay in the repairing process, but it did not stop its development. The irradiated nonsutured group was considered to show the greater delay when compared with the other groups.

Estudo dos efeitos de temporada de treinamento físico sobre a Performance de uma equipe de handebol feminino sub-21

Handball is a sport that demands endurance associated with fast and powerful actions such as jumps, blocks, sprints and throws. The aim of this study was to evaluate the effects of a 38-week systematic physical training applied to a women's under 21 handball team on upper and lower limb power, 30m sprints speed and endurance. The periodization applied was an adaptation of the Verkhoshansky theory, and aimed at two performance peaks during the season with six data collections. The median and range values for three kg medicine ball throwing was: 2.98m (2.15-3.50); 2.84m (2.43-3.20); 2.90m (2.60-3.38); 3.10 (2.83-3.81); 2.84 (2.55-3.57) and 3.34 (2.93-3.83). Regarding the three-pass running test: 5.60m (4.93-6.58); 5.37m (5.04-6.38); 5.36m (4.93-6.12); 5.65m (4.80-6.78); 5.63m (5.00-6.40) and 5.83m (5.14-6.05). Regarding the 30-m sprint test: 5.8m/s (5.45-6.44); 6,64 m/s (6,24-7,09); 5.65m/s (5.17-5.95); (there was not IV moment for this test); 6.19 m/s (5.57-6.26) and 5.83 (5.14-6.05).Regarding the 30-m sprint endurance test until 10% decrease: 4 sprints (4-6); 5 sprints (4-9); 4,5 sprints (4-16); (there was not IV moment for this test); 6 sprints (4-12) and 5 sprints (4-5). Significant differences (p<0.05) were observed in three kg medicine ball throwing and three-pass running tests at least in one of the performance peak planned, with no significant differences in 30-m sprint speed or endurance tests. The applied physical training was efficient at improving the specific physical fitness in the performance peaks, as well as giving support for better physical training adjustment for the upcoming season.