Effect of abutment`s height and framework alloy on the load distribution of mandibular cantilevered implant-supported prosthesis

In cantilevered implant-supported complete prosthesis, the abutments` different heights represent different lever arms to which the abutments are subjected resulting in deformation of the components, which in turn transmit the load to the adjacent bone. The purpose of this in vitro study was to quantitatively assess the deformation of abutments of different heights in mandibular cantilevered implant-supported complete prosthesis. A circular steel master cast with five perforations containing implant replicas (O3.75 mm) was used. Two groups were formed according to the types of alloy of the framework (CoCr or PdAg). Three frameworks were made for each group to be tested with 4, 5.5 and 7 mm abutments. A 100 N load was applied at a point 15 mm distal to the center of the terminal implant. Readings of the deformations generated on the mesial and distal aspects of the abutments were obtained with the use of strain gauges. Deformation caused by tension and compression was observed in all specimens with the terminal abutment taking most of the load. An increase in deformation was observed in the terminal abutment as the height was increased. The use of an alloy of higher elastic modulus (CoCr) also caused the abutment deformation to increase. Abutment`s height and framework alloy influence the deformation of abutments of mandibular cantilevered implant-supported prosthesis. To cite this article:Suedam V, Capello SouzaEA, Moura MS, Jacques LB, Rubo JH. Effect of abutment`s height and framework alloy on the load distribution of mandibular cantilevered implant-supported prosthesis. Clin. Oral Impl. Res. 20, 2009; 196-200.doi: 10.1111/j.1600-0501.2008.01609.x.

Human GC-AG alternative intron isoforms with weak donor sites show enhanced consensus at acceptor exon positions

It has been previously observed that the intrinsically weak variant GC donor sites, in order to be recognized by the U2-type spliceosome, possess strong consensus sequences maximized for base pair formation with U1 and U5/U6 snRNAs. However, variability in signal strength is a fundamental mechanism for splice site selection in alternative splicing. Here we report human alternative GC-AG introns (for the first time from any species), and show that while constitutive GC-AG introns do possess strong signals at their donor sites, a large subset of alternative GC-AG introns possess weak consensus sequences at their donor sites. Surprisingly, this subset of alternative isoforms shows strong consensus at acceptor exon positions 1 and 2. The improved consensus at the acceptor exon can facilitate a strong interaction with U5 snRNA, which tethers the two exons for ligation during the second step of splicing. Further, these isoforms nearly always possess alternative acceptor sites and always possess alternative acceptor sites and exhibit particularly weak polypyrimidine tracts characteristic of AG-dependent introns. The acceptor exon nucleotides are part of the consensus required for the U2AF(35)-mediated recognition of AG in such introns. Such improved consensus at acceptor exons is not found in either normal or alternative GT-AG introns having weak donor sites or weak polypyrimidine,tracts. The changes probably reflect mechanisms that allow GC-AG alternative intron isoforms to cope with two conflicting requirements, namely an apparent need for differential splice strength to direct the choice of alternative sites and a need for improved donor signals to compensate for the central mismatch base pair (C-A) in the RNA duplex of U1 snRNA and the pre-mRNA. The other important findings include (i) one in every twenty alternative introns is a GC-AG intron, and (ii) three of every five observed GC-AG introns are alternative isoforms.

The effect of trace elements on the sintering of an Al-Zn-Mg-Cu alloy

Trace elements can have a significant effect on the processing and properties of aluminium alloys, including sintered alloys. As little as 0.07 wt% (100 ppm) lead, tin or indium promotes sintering in an Al-Zn-Mg-Cu alloy produced from mixed elemental powders. This is a liquid phase sintering system and thin liquid films form uniformly throughout the alloy in the presence of the trace elements, but liquid pools develop in their absence. Analytical transmission electron microscopy indicates that the trace elements are confined to the interparticle and grain boundary regions. The sintering enhancement is attributed to the segregation of the microalloying addition to the liquid-vapour interface. Because the microalloying elements have a low surface tension, they lower the effective surface tension of the liquid. This reduces the wetting angle and extends the spreading of the liquid through the matrix. An improvement in sintering results. (C) 2001 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.

Mass balance characterisation of Al-7Si-Mg alloy microstructures as a function of solution treatment time

Mass balance calculations were performed to model the effect of solution treatment time on A356 and A357 alloy microstructures. Image analysis and electron probe microanalysis were used to characterise microstructures and confirm model predictions. In as-cast microstructures, up to 8 times more Mg is tied up in the pi-phase than in Mg2Si. The dissolution of pi is accompanied by a corresponding increase in the amount of beta-phase. This causes the rate of pi dissolution to be limited by the rate of beta formation. It is predicted that solution treatments of the order of tens of minutes at 540degreesC produce near-maximum T6 yield strengths, and that Mg contents in excess of 0.52 wt% have no advantage.

Powder forging of a sintered Al-3.8Cu-1Mg-0.8Si-O.1Sn alloy

The forging characteristics of an Al-Cu-Mg-Si-Sn alloy are examined using it new testing strategy which incorporates a double truncated cone specimen and finite element modelling. This sample geometry produces controlled strain distributions within a single specimen and can readily identify the specific strain required to achieve a specific microstructural event by matching the metallographic data with the strain profiles calculated from finite element software, The friction conditions were determined using the conventional friction ring test, which was evaluated using finite element software. The rheological properties of the alloy, evaluated from compression testing of right cylinders, are similar to the properties of conventional aluminium forgings. A hoop strain develops at the outer diameter of the truncated cones and this leads to pore opening at the outer few millimetres. The porosity is effectively removed when the total strain equals the net compressive strain. The strain profiles that develop in the truncated cones are largely independent of the processing temperature and the strain rate although the strain required for pore closure increases as the forging temperature is reduced. This suggests that the microstructure and the strain rate sensitivity may also be important factors controlling pore behaviour. (C) 2002 Elsevier Science B.V. All rights reserved.

Surface alloying of AZ91D alloy by diffusion coating

A new technique of surface modification by diffusion coating for AZ91D alloy was developed. A 1.0-2.0-mm alloy layer, which has hardness four to five times higher than the substrate metal, was formed after the treatment. Consequent solution treatment and aging could further improve the hardness of the alloy layer. Microstructure and chemical composition were investigated using optical microscope and electron probe.

Implanta????o do pr??-atendimento na ag??ncia dos correios Adolfina de Pinheiros em S??o Paulo

A experi??ncia da Diretoria Regional de S??o Paulo Metropolitana dos Correios objetiva implementar melhoria em um dos seus principais processos: o atendimento nas ag??ncias. Dentro do contexto de gest??o pela qualidade total, destacamos o programa de ger??ncia da rotina e gerenciamento de melhorias (revis??o de processos), cujas ferramentas nortearam o nosso projeto. Nas ag??ncias, em decorr??ncia dos diversos produtos e servi??os que a ECT comercializa, faz-se necess??ria a gest??o das filas para que o tempo de espera excessivo n??o ocasione a insatisfa????o dos clientes. Com a implanta????o do pr??-atendimento em guich?? espec??fico, na ag??ncia Adolfina de Pinheiros, houve uma redu????o significativa do tempo de espera na fila, servindo como modelo para implanta????o em outras ag??ncias dos Correios. Al??m de atender ?? necessidade do cliente, estabelecida na matriz do QFD (Desdobramento da Fun????o Qualidade) do sistema de gest??o da qualidade da ECT, o projeto objetiva tornar a rotina de trabalho dos atendentes de guich?? mais f??cil, racional e produtiva

Avalia????o das pr??ticas de gest??o do conhecimento na ag??ncia nacional de telecomunica????es

A Gest??o do Conhecimento ?? de suma import??ncia para as organiza????es em que o conhecimento desempenha papel essencial. Nesses casos, o conhecimento afeta o trabalho e determina mudan??as irrevers??veis, tanto na vida das organiza????es como das pessoas que l?? trabalham. Este estudo analisa o processo de planejamento, implementa????o e desenvolvimento de pr??ticas de gest??o do conhecimento na Anatel, Ag??ncia Nacional de Telecomunica????es. ?? orientado por uma abordagem te??rica que foca, particularmente, na sociedade em rede (Castells, 1999) e nas dimens??es da Gest??o do Conhecimento (Angeloni, 2008). Um grupo de servidores da Anatel foi entrevistado e responderam a um question??rio com o objetivo de se avaliar sua familiaridade com pr??ticas de Gest??o do Conhecimento. A inclus??o da Gest??o do Conhecimento como t??pico da nova vers??o do Regimento Interno da Ag??ncia foi examinada, para verificar se representa passo estrat??gico para sua ado????o pela Ag??ncia. O estudo avalia a motiva????o para a ado????o da Gest??o do Conhecimento, investiga a ocorr??ncia de pr??ticas de Gest??o do Conhecimento na Anatel, bem como o est??gio de sua implementa????o e o alcance de sua ado????o entre os usu??rios da Ag??ncia e pela sociedade em geral. Finalmente, o estudo analisa se as iniciativas j?? tomadas para implementar a Gest??o do Conhecimento s??o consistentes com as diretrizes estabelecidas no novo Regimento Interno e se tais a????es s??o coordenadas de forma a promover a efic??cia da Gest??o do Conhecimento na Anatel

An??lise da estrutura organizacional da fiscaliza????o do transporte rodovi??rio na ag??ncia nacional de transportes terrestres

Fiscalizar a presta????o dos servi??os de transporte interestadual e internacional de passageiros e de transporte rodovi??rio de cargas ?? atribui????o da Superintend??ncia de Fiscaliza????o da Ag??ncia Nacional de Transportes Terrestres ??? ANTT. Esta pesquisa visa analisar a efici??ncia e efic??cia desta estrutura organizacional

Texto para discuss??o 18: ag??ncias executivas: estrat??gias de reforma administrativa

Este trabalho tem por objeto uma an??lise do projeto ag??ncias executivas, que ?? um dos projetos integrantes do plano diretor da Reforma do Aparelho do Estado (plano diretor). Trata-se, essencialmente, da implanta????o da reforma administrativa nas autarquias e funda????es p??blicas federais, que operam no Setor de Atividades Exclusivas do Estado