Evaluation of the Bond Strength of Denture Base Resins to Acrylic Resin Teeth: Effect of Thermocycling

Purpose: The purpose of this study was to evaluate the thermocycling effects and shear bond strength of acrylic resin teeth to denture base resins. Materials and Methods: Three acrylic teeth (Biotone, Trilux, Ivoclar) were chosen for bonding to four denture base resins: microwave-polymerized (Acron MC), heat-polymerized (Lucitone 550 and QC-20), and light-polymerized (Versyo. bond). Twenty specimens were produced for each denture base/acrylic tooth combination and were divided into two groups (n = 10): without thermocycling (control groups) and thermocycled groups submitted to 5000 cycles between 4 and 60 degrees C. Shear strength tests (MPa) were performed with a universal testing machine at a crosshead speed of 1 mm/min. Statistical analysis of the results was carried out with three-way ANOVA and Bonferroni`s multiple comparisons post hoc analysis for test groups (alpha = 0.05). Results: The shear bond strengths of Lucitone/Biotone, Lucitone/Trilux, and Versyo/Ivoclar specimens were significantly decreased by thermocycling, compared with the corresponding control groups (p < 0.05). The means of Acron/Ivoclar and Lucitone/Ivoclar specimens increased after thermocycling (p < 0.05). The highest mean shear bond strength value was observed with Lucitone/Biotone in the control group (14.54 MPa) and the lowest with QC-20/Trilux in the thermocycled group (3.69 MPa). Conclusion: Some acrylic tooth/denture base resin combinations can be more affected by thermocycling; effects vary based upon the materials used.

Effect of methyl methacrylate monomer on bond strength of denture base resin to acrylic teeth

Bond failures at the acrylic teeth and denture base resin interface are still a common clinical problem in prosthodontics. The effect of methyl methacrylate (MMA) monomer on the bond strength of three types of denture base resins (Acron MC, Lucitone 550 and QC-20) to two types of acrylic teeth (Biotone and Trilux) was evaluated. Twenty specimens were produced for each denture base resin/acrylic tooth combination and were randomly divided into control (acrylic teeth received no surface treatment) and experimental groups (MMA was applied to the surface of the acrylic teeth for 180 s) and were submitted to shear tests (1 mm/mm). Data (MPa) were analyzed using three-way ANOVA/Student`s test (alpha = 0.05). MMA increased the bond strength of Lucitone denture base resins and decreased the bond strength of QC-20. No difference was detected for the bond strength of Acron MC base resin after treatment with MMA. (C) 2008 Elsevier Ltd. All rights reserved.

Recent dioxin contamination from Agent Orange in residents of a southern Vietnam city

Marked elevation of dioxin associated with the herbicide Agent Orange was recently found in 19 of 20 blood samples from persons living in Bien Hoa, a large city in southern Vietnam. This city is located near an air base that was used for Agent Orange spray missions between 1962 and 1970. A spill of Agent Orange occurred at this air base more than 30 years before blood samples were collected in 1999. Samples were collected, frozen, and sent to a World Health Organization-certified dioxin laboratory fm congener-specific analysis as part of a Vietnam Red Cross project. Previous analyses of more than 2200 pooled blood samples collected in the 1990s identified Bien Hoa as one of several southern Vietnam areas with persons having elevated blood dioxin levels from exposure to Agent Orange. In sharp contrast to this study, our previous research showed decreasing tissue dioxin levels over time since 1970. Only the dioxin that contaminated Agent Orange, 2,3, 7, 8-tetrachlmodibenzo-p-dioxin (TCDD), was elevated in the blood of 19 of 20 persons sampled from Bien Hoa. A comparison pooled sample from 100 residents of Hanoi, where Agent Orange was not used, measured blood TCDD levels of 2 parts per trillion (ppt). TCDD levels of up to 271 ppt, a 135-fold increase, were found in Bien Hoa residents. TCDD contamination was also found in some nearby soil and sediment samples. Persons new to this region and children born after Agent Orange spraying ended also had elevated TCDD levels. This TCDD uptake was recent and occurred decades after spraying ended. We hypothesize that a major route of current and past exposures is from the movement of dioxin from soil into river sediment, then into fish, and from fish consumption into people.

Phenotypic and genotypic analysis of Helicoverpa armigera nucleopolyhedrovirus serially passaged in cell culture

Rapid accumulation of few polyhedra (FP) mutants was detected during serial passaging of Helicoverpa armigera nucleopolyhedrovirus (HaSNPV) in cell culture. 100% FP infected cells were observed by passage 6. The specific yield decreased from 178 polyhedra per cell at passage 2 to two polyhedra per cell at passage 6. The polyhedra at passage 6 were not biologically active, with a 28-fold reduction in potency compared to passage 3. Electron microscopy studies revealed that very few polyhedra were produced in an FP infected cell (< 10 polyhedra per section) and in most cases these polyhedra contained no virions. A specific failure in the intranuclear nucleocapsid envelopment process in the FP infected cells, leading to the accumulation of naked nucleocapsids, was observed. Genomic restriction endonuclease digestion profiles of budded virus DNA from all passages did not indicate any large DNA insertions or deletions that are often associated with such FP phenotypes for the extensively studied Autographa californica nucleopolyhedrovirus and Gaileria mellonella nucleopolyhedrovirus. Within an HaSNPV 25K FP gene homologue, a single base-pair insertion (an adenine residue) within a region of repetitive sequences (seven adenine residues) was identified in one plaque-purified HaSNPV FP mutant. Furthermore, the sequences obtained from individual clones of the 25KFP gene PCR products of a late passage revealed point mutations or single base-pair insertions occurring throughout the gene. The mechanism of FP mutation in HaSNPV is likely similar to that seen for Lymantria dispar nucleopolyhedrovirus, involving point mutations or small insertions/deletions of the 25K FP gene.

Review of "Clearing the Smoke: Assessing the Science Base for Tobacco Harm Reduction"

Review of Clearing the Smoke: Assessing the Science Base for Tobacco Harm Reductionbby K. STRATTON, P. SHEATHE, R. WALLACE & S. BANDURANT Washington DC, National Academy Press, 2001, xix + 636 pp, US$49.95, ISBN 0309 07282 4 (hbk)

Synthesis and characterization of mono- and bis-ligand zinc(II) and cadmium(II) complexes of the di-2-pyridylketone Schiff base of S-benzyl dithiocarbazate (Hdpksbz) and the X-ray crystal structures of the [Zn(dpksbz)2] and [Cd(dpksbz)NCS]2 complexes

New mono- and bis-chelated zinc(II) and cadmium(II) complexes of formula, [M(dpksbz)NCS] (dpksbz = anionic form of the di-2-pyridylketone Schiff base of S-benzyldithiocarbazate) and [M(dpksbz)(2)] (M = Zn-II, Cd-II) have been prepared and characterized. The structure of the bis-ligand complex, [Zn(dpksbZ)(2)] has been determined by X-ray diffraction. The complex has a distorted octahedral geometry in which the ligands are coordinated to the zinc(II) ion as uninegatively charged tridentate chelates via the thiolate sulfur atoms, the azomethine nitrogen atoms and the pyridine nitrogen atoms. The distortion from a regular octahedral geometry is attributed to the restricted bite angles of the Schiff base ligands. X-ray structural analysis shows that the [Cd(dpksbz)NCS](2) complex is a centrosymmetric dimer in which each of the cadmium(II) ions adopts a five-coordinate, approximately square-pyramidal configuration with the Schiff base acting as a tetradentate chelating agent coordinating a cadmium(II) ion via one of the pyridine nitrogen atoms, the azomethine nitrogen atom and the thiolate sulfur atom; the second pyridine nitrogen atom is coordinated to the other cadmium(II) ion of the dimer. The fifth coordination position around each cadmium(II) is occupied by an N-bonded thiocyanate ligand. (C) 2003 Elsevier Science Ltd. All rights reserved.

Programa de apoio ao desenvolvimento de novas empresas de base tecnol??gica agropecu??ria e ?? transfer??ncia de tecnologia (Proeta)

Em dezembro de 2001, o Proeta foi criado pela Empresa Brasileira de Pesquisa Agropecu??ria (Embrapa) com apoio financeiro do Fundo Multilateral de Investimentos do Banco Interamericano de Desenvolvimento (Fumin/BID), por meio de um acordo de coopera????o t??cnica n??o-reembols??vel. O programa tem o objetivo de contribuir para a transfer??ncia de tecnologias e conhecimentos gerados pela Embrapa para empreendimentos de base tecnol??gica, mediante a utiliza????o do processo de incuba????o de empresas. Para concretizar a iniciativa, foram estabelecidas experi??ncias-piloto em cinco unidades de pesquisa da Embrapa, estrategicamente situadas nas regi??es Nordeste, Centro-Oeste e Sudeste. Entre os resultados e avan??os obtidos merecem destaque 21 tecnologias disponibilizadas, 14 conv??nios firmados com incubadoras, 16 propostas de neg??cios apresentadas, 14 empresas pr??-selecionadas e incubadas, e uma empresa graduada. A consolida????o das alian??as e parcerias no processo de incuba????o resultou em um sistema de inova????o que auxilia o desenvolvimento sustent??vel da cadeia produtiva do agroneg??cio, gerando benef??cios para a sociedade em geral

Programa de Racionaliza????o de Processos com base na Aprendizagem Organizacional: PRPAO

O Programa de Racionaliza????o de Processos com base na Aprendizagem Organizacional (PRPAO), unindo os princ??pios da organiza????o racional e da organiza????o de aprendizagem, teve como objetivo levantar e aplicar os meios mais eficientes para a consecu????o das tarefas di??rias, incorporando conhecimentos e novas pr??ticas de gest??o ?? organiza????o. Por ocasi??o de sua implementa????o, primeiramente procurou-se identificar a forma como as atividades eram realizadas; em seguida, detectar as id??ias e os conhecimentos existentes para melhoria dessas atividades; e, por ??ltimo, por meio de prioriza????es, implementar as mudan??as sugeridas. O principal recurso utilizado nesse programa foi o humano, sobretudo voltado para capacidade de gerir id??ias, n??o havendo, no momento, necessidade de despesas extras com consultoria. Os resultados foram surpreendentes, pois medidas simples trouxeram uma redu????o no tempo gasto, de mais de 80%, em determinados processos e uma economia de recursos financeiros superior a 20%

Produtividade e sa??de financeira: a import??ncia da venda de servi??os pela Base Naval de Natal para clientes extra: Marinha

A Marinha, com sua vis??o para o futuro e preocupada com a dificuldade de mensura????o dos custos de suas organiza????es industriais e prestadoras de servi??os, instituiu, a partir de 1994, o sistema de Organiza????es Militares Prestadoras de Servi??os (OMPS). Nesse contexto, a base Naval de Natal (BNN) precisou encontrar propostas que a mantivesse superavit??ria. Para tal, tornou-se necess??rio o engajamento de todos os n??veis da OM para, dentro de uma vis??o sist??mica de mensura????o existente, atingir um desempenho global satisfat??rio. Ap??s a implanta????o da iniciativa, alcan??ou-se o aumento substancial do faturamento, com rela????o aos clientes extra-Marinha, a redu????o dos prazos de prontifica????o dos servi??os prestados, sem queda na qualidade e com a constante preocupa????o de se verificar o n??vel de satisfa????o do cliente; o incremento da terceiriza????o consciente; o surgimento de parcerias com a iniciativa privada que geraram a otimiza????o da capacidade instalada em algumas oficinas; maior agilidade no processo de obten????o, devido a uma melhor coordena????o entre as ??reas industrial e de log??stica; e a possibilidade de investimentos na ??rea industrial e nas condi????es de trabalho,em decorr??ncia do aumento da produtividade

Uma base para o desenvolvimento de estrat??gias de aprendizagem para a gest??o de riscos no servi??o p??blico

Este Caderno traz o relat??rio elaborado pela Mesa-Redonda de Pesquisa A????o sobre Gest??o de Riscos, do Centro Canadense para o Desenvolvimento da Gest??odo Canad??, que objetiva principalmente avaliar as v??rias iniciativas e estudos realizados, identificar princ??pios b??sicos e pr??ticas positivas e definir mecanismos para estimular a divulga????o de estudos te??ricos e medidas pr??ticas no campo da gest??o de riscos

Base flutuante de fiscaliza????o federal integrada

Este projeto consiste na celebra????o de conv??nios entre a Superintend??ncia Regional da Secretaria da Receita Federal no Par?? com as principais institui????es envolvidas nas atividades de policiamento da Amaz??nia, visando reduzir a pr??tica do contrabando, narcotr??fico e a devasta????o do meio-ambiente causada pela extra????o indiscriminada de madeiras. O conv??nio foi celebrado entre a Pol??cia Federal, IBAMA, SUFRAMA e Secretaria de Estado da Fazenda. No munic??pio de ??bidos ??? PA, por onde passam todas as embarca????es procedentes da Zona Franca de Manaus com destino ??s cidades de Santar??m e Bel??m ??? PA, foi constru??da uma base flutuante denominada Candiru, a qual se constitui em um eficiente mecanismo de vigil??ncia e repress??o ?? pr??tica do contrabando via fluvial

SargSUS: sistema de apoio ?? constru????o do relat??rio anual de gest??o do SUS

O Sistema de Apoio ?? Elabora????o do Relat??rio Anual de Gest??o do SUS (SargSUS) consiste em uma ferramenta eletr??nica desenvolvida em meados de 2009, pela Secretaria de Gest??o Estrat??gica e Participativa do Minist??rio da Sa??de (SGEP/MS). A natureza inovadora do sistema SargSUS est?? na possibilidade concreta que sua utiliza????o tem de promover a integra????o das a????es dos diversos setores das secretarias de sa??de, quando da elabora????o do Relat??rio de Gest??o, integra????o das informa????es existentes em bases de dados distintas, da indu????o do processo de articula????o dos instrumentos de planejamento, qualificando a tomada de decis??o. Outro aspecto a ser destacado diz respeito ao apoio ?? participa????o e ao controle social e subs??dio ao trabalho, interno e externo, de controle e auditoria, fazendo com que, em 2013, 100% dos gestores do SUS adotassem a ferramenta para a presta????o de contas junto aos conselhos de sa??de

Os primórdios da amizade na infância : a perspectiva materna

A investigação da origem ontogenética da amizade apresenta dificuldades conceituais e metodológicas. O presente artigo investigou como mães de crianças entre um e três anos percebiam as primeiras amizades de seus filhos. Vinte mães entre 24 e 48 anos foram entrevistadas com base em um roteiro pré-estabelecido. Os resultados indicaram que o conceito de amizade das mães era muito positivo. A rede de amigos dos filhos era formada por crianças da família, da vizinhança ou de comunidades religiosas. A principal atividade compartilhada com amigos foi o brincar. As mães facilitavam o encontro dos filhos com amigos ou amigos em potencial e serviam de mediadoras entre os padrões sócio-culturais e essas amizades, contribuindo para a sua construção de acordo com as expectativas sócio-culturais. As primeiras amizades foram identificadas por volta dos 18 meses. Pode-se concluir que as mães participavam ativamente da formação das primeiras amizades dos filhos.