Compósitos de borracha natural com polianilina

Compósitos de borracha natural (Hevea brasiliensis)-BN/polianilina - PANI, com diferentes composições foram obtidos através da polimerização por emulsão do monômero anilina na presença da BN e do ácido dodecilbenzeno sulfônico (DBSA). Filmes finos e homogêneos foram obtidos por prensagem a quente. Os compósitos foram caracterizados por condutividade elétrica, FTIR, UV-vis-NIR, DSC e difração de raios X. Compósito com condutividade elétrica cerca de 14 ordens de grandeza maior que a BN foi obtido. Este alto valor de condutividade é atribuído à formação da PANI no estado dopado no compósito, que foi verificado através das técnicas de UV-vis-NIR e FTIR. Os resultados obtidos com a técnica de DSC e difratometria de raios X indicaram que os polímeros são imiscíveis e que a presença da borracha não altera significantemente a fase cristalina da PANI-DBSA no compósito.

Propriedades químicas de um latossolo vermelho distrófico de cerrado sob diferentes usos e manejos

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Distribuição espacial de Tenuipalpus heveae Baker (Acari: Tenuipalpidae) na cultura da seringueira

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Prediction of Hevea progeny performance in the presence of genotype-environment interaction

Twenty two open-pollinated Hevea progenies from different parental clones of the Asian origin were tested at five sites in the Northwestern São Paulo State Brazil to investigate the progeny girth growth, rubber yield, bark thickness and plant height. Except for the rubber yield, the analysis of variance indicated highly significant (p<0.01) genotype x environment interaction and heterogeneity of regressions among the progenies. However, the regression stability analysis identified only a few interacting progenies which had regression coefficients significantly different from the expected value of one. The linear regressions of the progeny mean performance at each test on an environmental index (mean of all the progenies in each test) showed the general stability and adaptability of most selected Hevea progenies over the test environments. The few progenies which were responsive and high yielding on different test sites could be used to maximize the rubber cultivars productivity and to obtain the best use of the genetically improved stock under different environmental conditions.

Temporal stability for unpredictable annual climatic variability for Hevea genotype selection

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ganho genético com base no tamanho efetivo populacional de progênies de seringueira

O objetivo deste trabalho foi estimar os ganhos genéticos de um teste de progênies de seringueira para a produção de borracha seca e, com base no maior tamanho efetivo populacional e maior ganho genético, obter os melhores indivíduos. Foram utilizadas 30 progênies de meios-irmãos, provenientes de sementes de polinização mista - alogamia e autogamia - de testes clonais no Estado de São Paulo. Utilizou-se o delineamento experimental de blocos ao acaso, com 30 tratamentos (progênies), 3 repetições e parcelas lineares de 10 plantas, em um espaçamento de 3x3 m, o que totalizou 900 plantas úteis. Aos três anos, o perímetro, a 50 cm do solo (PA50), e a produção de borracha seca (PBS) foram avaliadas por meio do teste precoce de produção Hamaker Morris-Mann (HMM). As variáveis foram analisadas pelo método de modelo linear misto, via procedimento REML/BLUP, em progênies com sistema reprodutivo misto e taxa de autofecundação de 22%. A identificação dos 20 melhores indivíduos quanto à PBS e ao PA50 proporcionou ganho genético de 67,96 e 16,48%, respectivamente, e um coeficiente de endogamia de aproximadamente 2,82%. O teste de progênies proporciona produção de sementes com melhor valor genético, grande variabilidade e baixa endogamia

Tropical dermatology: Venomous arthropods and human skin Part I. Insecta

Although many tropical insects carry infectious diseases, cutaneous injury can occur by other mechanisms, for example erucism (envenomation by caterpillars) or lepidopterism (dermatitis from moths). Pararama is a unique form of erucism seen in workers in contact with rubber trees in the Amazon, and it is caused by Premolis larvae, resulting in progressive periarticular fibrosis, ankylosis, and the loss of articulation. Ants and aquatic insects of the Belostomatidae family can cause painful bites and stings. Anaphylactic shock and death can result from the venom of bees and wasps. Beetles can cause vesicular dermatitis via cantharidin or paederin. Myiasis results from fly larvae (maggots) feeding on live or necrotic tissue of humans or other hosts, while New World screwworm fly larvae feed only on living tissue and burrow (ie, screw) more deeply when attempts are made to remove them. Tungiasis is characterized by very pruritic and painful papules and ulcers resulting from a Tunga flea penetrating the host's skin. Dermatologists should be able to diagnose and treat the cutaneous manifestations of these tropical insects and educate their patients on prevention. (J Am Acad Dermatol 2012; 67:339.e1-14.)

ESTUDO da RETENÇÃO ENTRE RESINA ACRÍLICA PARA BASE DE DENTADURA E DENTES DE RESINA ACRÍLICA

Foi avaliada a resistência de união entre dentes e base de dentadura, ambos de resina acrílica. Os dentes foram incluídos em blocos cilíndricos de resina e, posteriormente, torneados, para se obterem cilindros de 5mm de diâmetro. Sobre a extremidade do dente, era adaptado um padrão de cera de mesmo diâmetro, que, após inclusão na mufla, era substituído por resina acrílica termicamente ativada pelo método de processamento convencional de base de dentadura. Como variáveis, usaram-se duas marcas de dentes, duas fases de inclusão (plástica e borrachóide) e aplicação ou não de detergente e monômero sobre os dentes. Os corpos-de-prova, antes dos ensaios de ruptura por tração, foram armazenados em água destilada, a 37ºC, por 2 semanas. Os resultados mostraram que: marca de dente e fase de condensação não influíram nos resultados; somente o uso de detergente ou de monômero aumenta a retentividade e o seu uso conjunto apresenta efeito acumulativo.

Evaluation of enamel surface after bracket debonding and polishing

INTRODUÇÃO: a preservação da estrutura de esmalte após a remoção dos acessórios ortodônticos é obrigação do clínico. Portanto, procura-se um protocolo de descolagem com bases científicas. OBJETIVO: objetivou-se avaliar por microscopia eletrônica de varredura (MEV) a influência de quatro protocolos de remoção de braquetes e polimento da superfície do esmalte e propor um protocolo que minimize os danosà superfície do esmalte. MÉTODOS: doze incisivos permanentes bovinos foram divididos em quatro grupos de acordo com os instrumentos utilizados para a descolagem dos braquetes e remoção do remanescente adesivo. Os braquetes foram descolados com o alicate de descolagem reto (Ormco Corp.) nos grupos 1 e 2, e com o instrumento de descolagem Lift-Off (3M Unitek) nos grupos 3 e 4. Os remanescentes adesivos dos grupos 1 e 3 foram removidos com o alicate removedor de resina longo (Ormco Corp.) e dos grupos 2 e 4 com broca de carboneto de tungstênio (Beavers Dental) em alta-rotação. As superfícies, após cada etapa da descolagem e polimento, foram avaliadas em réplicas de resina epóxica e foram obtidas eletromicrografias com aumento de 50 e 200X. RESULTADOS: os quatro protocolos de remoção de acessórios ortodônticos e polimento ocasionaram irregularidades no esmalte. Conclusão: a remoção do braquete com o alicate de descolagem reto, seguido da remoção do remanescente adesivo com broca de carboneto de tungstênio e polimento final com pasta de pedra-pomes foi o procedimento que ocasionou menores danos ao esmalte, sendo o protocolo sugerido para a remoção dos acessórios ortodônticos.

Clinical assessment of postoperative sensitivity in posterior composite restorations

This incidence of postoperative sensitivity was evaluated in resin-based posterior restorations. Two hundred and ninety-two direct restorations were evaluated in premolars and molars. A total of 143 Class I and 149 Class 11 restorations (MO/OD and MOD) were placed in patients ranging in age from 30 to 50 years. After the cavity preparations were completed, a rubber dam was placed, and the preparations were restored using a total-etch system (Prime & Bond NT) and a resin-based restorative material (TPH Spectrum). The patients were contacted after 24 hours and 7, 30 and 90 days postoperatively and questioned regarding the presence of sensitivity and the stimuli that triggered that sensitivity. The Chi-square and Fisher's Exact Test were used for statistical analysis. Evaluation at 24 hours after restorative treatment revealed statistically significant differences among the types of cavity preparations restored and the occurrence of postoperative sensitivity (p=0.0003), with a higher frequency of sensitivity in Class H MOD restorations (26%), followed by Class II MO/DO (15%) and Class I restorations (5%). At 7, 30 and 90 days after restorative treatment, there was a decrease in the occurrence of sensitivity for all groups. The percentage of sensitivity among the groups was not significantly different. This study shows that the occurrence of sensitivity is correlated with the complexity of the restoration.

Human pulp responses to in-office tooth bleaching

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Primary Tooth Enamel Loss After Manual and Mechanical Microabrasion

Purpose: This study's purpose was to assess the amount of dental enamel loss on primary incisors after manual or mechanical microabrasion with a phosphoric acid/pumice poste. Methods: Ten exfoliated primary maxillary incisors were bisected faciolingually and the resulting 20 halves were randomly assigned to 2 groups: group 1 (N=10) manual technique (plastic spatula); and group 2 (N=10) mechanical technique (rubber cup attached to a low-speed handpiece). Microabrasion was performed on the buccal surface using an abrasive paste prepared with 37% phosphoric acid and pumice. Ten 20-second applications alternated with 20-second risings were performed in each group. Enamel thickness measurements made under stereomi-croscopy before and after microabrasion were analyzed statistically by analysis of variance and pairwise t test. Results: There was a statistically significant difference (P=.003) between the manual and mechanical techniques. The mechanical technique produced a mean enamel loss of 274.16 mu m (66% of total enamel thickness), while the mean enamel loss with the manual technique was 152.59 mu m (39% of total enamel thickness). Conclusion: Manual microabrasion using a plastic spatula removed less enamel, but was sufficient to eliminate most superficial stains and defects, and may be a viable option for the microabrasive technique on primary teeth. (Pediatr Dent 2008;30:420-3) Received March 15, 2007 / Lost Revision September 19, 2007 / Revision Accepted October 19, 2007

Electrolytic treatment applied to the industrial effluent containing persistent wastes monitored by Bartha respirometric assays

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Use of Fruit Essential Oils to Assist Forest Regeneration by Bats

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Physiological importance of the coronary arterial blood supply to the rattlesnake heart

The reptilian heart consists of a thick inner spongy myocardium that derives its oxygen and nutrient supply directly from the blood within the ventricular cavity, which is surrounded by a thin outer compact layer supplied by coronary arteries. The functional importance of these coronary arteries remains unknown. In the present study we investigate the effects of permanent coronary artery occlusion in the South American rattlesnake (Crotalus durissus) on the ability to maintain heart rate and blood pressure at rest and during short term activity. We used colored silicone rubber (Microfil) to identify the coronary artery distribution and interarterial anastomoses. The coronary circulation was occluded and the snakes were then kept for 4 days at 30 degrees C. Microfil injections verified that virtually all coronary arteries had successfully been occluded, but also made visible an extensive coronary supply to the outer compact layer in untreated snakes. Electrocardiogram (ECG), blood pressure (P(sys)) and heart rate (f(H)) were measured at rest and during enforced activity at day 1 and 4. Four days after occlusion of the coronary circulation, the snakes could still maintain a P(sys) and f(H) of 5.2 +/- 0.2 kPa and 58.2 +/- 2.2 beats min(-1), respectively, during activity and the ECG was not affected. This was not different from sham-operated snakes. Thus, while the outer compact layer of the rattlesnake heart clearly has an extensive coronary supply, rattlesnakes sustain a high blood pressure and heart rate during activity without coronary artery blood supply.