Micro-Shear Bond Strength of Different Adhesives to Human Dental Enamel

The aim of this study was to evaluate the micro-shear bond strength of 5 adhesive systems to enamel, one single-bottle acid-etch adhesive (O), two self-etching primers (P) and two all-in-one self-etching adhesives (S). Method: Sixty premolar enamel surfaces (buccal or lingual) were ground flat with 400- and 600-grit SiC papers and randomly divided into 5 groups (n=12), according to the adhesive system.. SB2 - Single Bond 2 (O); CSE - Clearfil SE Bond (P); ADS - AdheSE (P); PLP - Adper Prompt L-Pop (S); XE3 - Xeno III (S). Tygon tubing (inner diameter of 0.8mm) restricted the bonding area to obtain the resin composite (Z250) cylinders. After storage in distilled water at 37 degrees C for 24h and thermocycling, micro-shear testing was performed (crosshead speed of 0.5mm/min). Data were submitted to one-way ANOVA and Tukey test (a=5%). Samples were also subjected to stereomicroscopic and SEM evaluations after micro-shear testing. Mean bond strength values (MPa +/- SD) and the results of Tukey test were: SB2: 36.36(+/- 3.34)a; ADS: 33.03(+/- 7.83)a; XE3: 32.76(+/- 5.61)a; CSE: 30.61(+/- 6.68)a; PLP: 22.17(+/- 6.05)b. Groups with the same letter were not statistically different. It can be concluded that no significant difference was there between SB2, ADS, XE3 and CSE, in spite of different etching patterns of these adhesives. Only PLP presented statistically lower bond strengths compared with others. J Clin Pediatr Dent 35(3): 301-304, 2011

Does workforce participation empower women? Micro-level evidence from urban Bangladesh

Empirical studies on the impact of women’s paid jobs on their empowerment and welfare in the Bangladesh context are rare. The few studies on the issue to date have all been confined to the garment workers only although studies indicate that women’s workforce participation in Bangladesh has increased across-the-board. Besides, none of these studies has made an attempt to control for the non-working women and/or applied any statistical technique to control for the effects of other pertinent determinants of women’s empowerment and welfare such as education, age, religion and place of living. This study overcomes these drawbacks and presents alternative assessments of the link between women’s workforce participation and empowerment on the basis of survey data from the two largest cities in Bangladesh. While the generic assessment indicates that women’s paid jobs have positive implications for women’s participation in decisions on fertility, children’s education and healthcare as well as their possession and control of resources, the econometric assessment negates most of these observations. Women’s education, on the other hand, appears to be more important than their participation in the labour force. The study underlines the fact that by omitting other relevant explanatory variables from the analysis, the previous studies might have overestimated the impact of women’s paid work on their empowerment. Among other things, the paper also highlights the importance of women’s job category, religion and regional differences for women’s empowerment.

Flat-Oval Root Canal Preparation with Self-Adjusting File Instrument: A Micro-Computed Tomography Study

Introduction: The aim of this study was to evaluate the root canal preparation in flat-oval canals treated with either rotary or self-adjusting file (SAF) by using micro-tomography analysis. Methods: Forty mandibular incisors were scanned before and after root canal instrumentation with rotary instruments (n = 20) or SAF (n = 20). Changes in canal volume, surface area, and cross-sectional geometry were compared with preoperative values. Data were compared by independent sample t test and chi(2) test between groups and paired sample t test within the group (alpha = 0.05). Results: Overall, area, perimeter, roundness, and major and minor diameters revealed no statistical difference between groups (P > .05). In the coronal third, percentage of prepared root canal walls and mean increases of volume and area were significantly higher with SAF (92.0%, 1.44 +/- 0.49 mm(3), 0.40 +/- 0.14 mm(2), respectively) than rotary instrumentation (62.0%, 0.81 +/- 0.45 mm(3), 0.23 +/- 0.15 mm2, respectively) (P < .05). SAF removed dentin layer from all around the canal, whereas rotary instrumentation showed substantial untouched areas. Conclusions: In the coronal third, mean increases of area and volume of the canal as well as the percentage of prepared walls were significantly higher with SAF than with rotary instrumentation. By using SAF instruments, flat-oval canals were homogenously and circumferentially prepared. The size of the SAF preparation in the apical third of the canal was equivalent to those prepared with #40 rotary file with a 0.02 taper. (J Endod 2011;37:1002-1007)

The anatomy of two-rooted mandibular canines determined using micro-computed tomography

P>Aim To investigate the internal and external anatomy of extracted human mandibular canines with two roots and two distinct canals using micro-computed tomography (mu CT). Methodology Fourteen two-rooted human mandibular canines were scanned using a high-resolution mu CT system (SkyScan 1174v2; SkyScan N.V., Kontich, Belgium). The images were processed to evaluate the size of the roots, the furcation regions, the presence of accessory canals, the mean distances between several anatomical landmarks, the position of the apical foramina, the direction of root curvatures, the cross-sectional appearances (SMI index), the volume and surface areas of the root canals. Results Root bifurcation was located in both apical (44%, n = 6) and middle (58%, n = 8) thirds of the root. The size of the buccal and lingual roots was similar in 29% of the sample. From a buccal view, no curvature towards the lingual or buccal direction occurred in either roots. From a proximal view, no straight lingual root occurred. In both views, S-shaped roots were found in 21% of the specimens. Location of the apical foramen varied considerably, tending to the mesio-buccal aspect of both roots. Lateral and furcation canals were observed mostly in the cervical third in 29% and 65% of the sample, respectively. The structure model index (SMI) index ranged from 1.87 to 3.86, with a mean value of 2.93 +/- 0.46. Mean volume and area of the root canals were 11.52 +/- 3.44 mm3 and 71.16 +/- 11.83 mm2, respectively. Conclusions The evaluation of two-rooted mandibular canines revealed that bifurcations occurred in the apical and middle third. S-shaped roots were found in 21% of the specimens. Mean volume, surface area and SMI index of the root canals were 11.52 mm3, 71.16 mm2 and 2.93, respectively.

Characterization of micro-mesoporous carbon media

A simple method to characterize the micro and mesoporous carbon media is discussed. In this method, the overall adsorption quantity is the sum of capacities of all pores (slit shape is assumed), in each of which the process of adsorption occurs in two sequential steps: the multi-layering followed by pore filling steps. The critical factor in these two steps is the enhancement of the pressure of occluded 'free' molecules in the pore as well as the enhancement of the adsorption layer thickness. Both of these enhancements are due to the overlapping of the potential fields contributed by the two opposite walls. The classical BET and modified Kelvin equations are assumed to be applicable for the two steps mentioned above, with the allowance for the enhanced pore pressure, the enhanced adsorption energy and the enhanced BET constant,all of which vary with pore width. The method is then applied to data of many carbon samples of different sources to derive their respective pore size distributions, which are compared with those obtained from DFT analysis. Similar pore size distributions (PSDs) are observed although our method gives sharper distribution. Furthermore, we use our theory to analyze adsorption data of nitrogen at 77 K and that of benzene at 303 K (ambient temperature). The PSDs derived from these two different probe molecules are similar, with some small differences that could be attributed to the molecular properties, such as the collision diameter. Permeation characteristics of sub-critical fluids are also discussed in this paper. (C) 2001 Elsevier Science B.V. All rights reserved.

Micro-mechanical approximation to the stress field around an inclined fiber of FRCC

Matrix spalling or crushing is one of the important mechanisms of fiber-matrix interaction of fiber reinforced cementitious composites (FRCC). The fiber pullout mechanisms have been extensively studied for an aligned fiber but matrix failure is rarely investigated since it is thought not to be a major affect. However, for an inclined fiber, the matrix failure should not be neglected. Due to the complex process of matrix spalling, experimental investigation and analytical study of this mechanism are rarely found in literature. In this paper, it is assumed that the load transfer is concentrated within the short length of the inclined fiber from the exit point towards anchored end and follows the exponential law. The Mindlin formulation is employed to calculate the 3D stress field. The simulation gives much information about this field. The 3D approximation of the stress state around an inclined fiber helps to qualitatively understand the mechanism of matrix failure. Finally, a spalling criterion is proposed by which matrix spalling occurs only when the stress in a certain volume, rather than the stress at a small point, exceeds the material strength. This implies some local stress redistribution after first yield. The stress redistribution results in more energy input and higher load bearing capacity of the matrix. In accordance with this hypothesis, the evolution of matrix spalling is demonstrated. The accurate prediction of matrix spalling needs the careful determination of the parameters in this model. This is the work of further study. (C) 2002 Elsevier Science Ltd. All rights reserved.

Characterization of micro-mesoporous carbonaceous materials. Calculations of adsorption isotherm of hydrocarbons

In this paper we apply a method recently developed by Do and co-workers(1) for the prediction of adsorption isotherms of pure vapors on carbonaceous materials. The information required for the prediction is the pore size distribution and the BET constant, C, of a corresponding nonporous surface (graphite). The dispersive adsorption force is assumed to be the dominant force in adsorption mechanism. This applies to nonpolar and weakly polar hydrocarbons. We test this predictive model against the adsorption data of benzene, toluene, n-pentane, n-hexane, and ethanol on a commercial activated carbon. It is found that the predictions are excellent for all adsorbates tested with the exception of ethanol where the predicted values are about 10% less than the experimental data, and this is probably attributed to the electrostatic interaction between ethanol molecules and the functional groups on the carbon surfaces.

Effects of adsorbate-adsorbate interaction in the description of adsorption isotherm of hydrocarbons in micro-mesoporous carbonaceous materials

In this paper, we present a model accounting for the adsorbate-adsorbate interaction in the adsorbed phase in the description of adsorption of pure vapors on carbonaceous materials. The details of the adsorbate-adsorbate interaction of a particular species are obtained from the analysis of its adsorption data on non-porous carbon black. The predictability of the model is tested against the adsorption isotherm data for benzene, toluene, n-pentane, n-hexane, carbon tetrachloride, methanol and ethanol on microporous activated carbon. It was found that the model prediction for non-polar adsorbates are satisfactory while it under-predicts for polar adsorbates, which is attributed to their additional interaction with functional groups. (C) 2002 Elsevier Science B.V. All rights reserved.

Simulation of the micro-physics of rocks using LSMearth

The particle-based Lattice Solid Model (LSM) was developed to provide a basis to study the physics of rocks and the nonlinear dynamics of earthquakes (MORA and PLACE, 1994; PLACE and MORA, 1999). A new modular and flexible LSM approach has been developed that allows different microphysics to be easily included in or removed from the model. The approach provides a virtual laboratory where numerical experiments can easily be set up and all measurable quantities visualised. The proposed approach provides a means to simulate complex phenomena such as fracturing or localisation processes, and enables the effect of different micro-physics on macroscopic behaviour to be studied. The initial 2-D model is extended to allow three-dimensional simulations to be performed and particles of different sizes to be specified. Numerical bi-axial compression experiments under different confining pressure are used to calibrate the model. By tuning the different microscopic parameters (such as coefficient of friction, microscopic strength and distribution of grain sizes), the macroscopic strength of the material and can be adjusted to be in agreement with laboratory experiments, and the orientation of fractures is consistent with the theoretical value predicted based on Mohr-Coulomb diagram. Simulations indicate that 3-D numerical models have different macroscopic properties than in 2-D and, hence, the model must be recalibrated for 3-D simulations. These numerical experiments illustrate that the new approach is capable of simulating typical rock fracture behaviour. The new model provides a basis to investigate nucleation, rupture and slip pulse propagation in complex fault zones without the previous model limitations of a regular low-level surface geometry and being restricted to two-dimensions.

An??lise da implementa????o do Programa Sistema Brasiliero de Tecnologia Sibratec Modalidade Extens??o Tecnol??gica

Este trabalho apresenta uma an??lise do processo de implementa????o do Programa Sistema Brasileiro de Tecnologia ??? SIBRATEC, programa do MCTI cujo objetivo geral ?? promover extens??o tecnol??gica para solucionar pequenos gargalos na gest??o tecnol??gica, adapta????o de produtos e processos e a melhoria da gest??o da produ????o das micro, pequenas e m??dias empresas, bem como desenvolver o fomento ?? expans??o do conhecimento cient??fico nas empresas.O objetivo deste trabalho foi avaliar o formato e a adequa????o dessa modalidade do programa a partir da contextualiza????o da implementa????o de pol??ticas que visam ao desenvolvimento da Ci??ncia Tecnologia e Inova????o ??? C T&I no Brasil, da caracteriza????o da pol??tica p??blica lan??adas e da coleta de dados, por meio de question??rio, sobre a percep????o dos coordenadores das redes apoiados pelo programa. A pesquisa permitiu concluir que o programa est?? alinhado ??s caracter??sticas da pol??tica atual de C T&I e que sua implementa????o ?? centrada na avalia????o ex-post. O programa foi considerado bastante adequado pelos coordenadores dos projetos de pesquisa apoiados. Em contrapartida, a continua????o do programa necessita de ajustes para que os objetivos previstos sejam alcan??ados em sua totalidade e a sistematiza????o da avalia????o do programa poder?? se constituir em uma ferramenta bastante ??til na gera????o dos subs??dios necess??rios para a tomada de decis??o sobre os novos rumos do Programa Sibratec

Redes de capacita????o: a experi??ncia da Escola de Governo e das universidades p??blicas do estado do Paran??

No Estado do Paran??, o movimento de forma????o e desenvolvimento dos servidores p??blicos ?? difundido a partir da cria????o da Escola de Governo, em 2004. Este artigo tem como objetivo apresentar a experi??ncia da constru????o de uma rede de capacita????o em pol??ticas p??blicas voltada ?? qualifica????o dos quadros de carreira de n??vel superior, analisando os desdobramentos e os fatores limitadores da rede. Apresenta a rede de capacita????o constru??da em parceria entre a Escola de Governo do Paran?? e seis Institui????es P??blicas de Ensino Superior (Universidade Estadual de Londrina, Universidade Estadual de Maring??, Universidade Estadual de Ponta Grossa, Universidade do Centro-Oeste do Paran??, Universidade do Oeste do Paran??, e a Universidade Federal do Paran??). A metodologia utilizada neste paper ?? o estudo de caso que relatar?? a constru????o da rede de capacita????o com as seguintes etapas: identifica????o dos diversos atores e a institui????o de c??mara t??cnica para a discuss??o e formata????o de curso de especializa????o que atendesse ??s necessidades e especificidades da Escola de Governo do Paran??; o processo seletivo; o desenvolvimento do Curso de P??s-Gradua????o, pelas Universidades p??blicas parceiras; o acompanhamento do Curso pela equipe da Escola de Governo do Paran??; os projetos de interven????o feitos pelos alunos; a dissemina????o do conhecimento produzido. O ponto alto do trabalho em rede se deu com as discuss??es do Curso na C??mara T??cnica: tem??tica do curso, fontes de recursos, projeto do curso, o p??blico-alvo, o ambiente de aprendizagem, o acesso ?? tecnologia, o suporte acad??mico e administrativo, o acompanhamento e avalia????o, a difus??o/dissemina????o do conhecimento. Dos resultados obtidos a partir da intera????o entre os integrantes da rede destacam-se: 19 turmas de um curso de P??s-Gradua????o em Formula????o e Gest??o de Pol??ticas P??blicas num total de 572 especialistas, al??m da realiza????o de um Semin??rio de Gest??o P??blica no Paran??, da cria????o do Reposit??rio Institucional SabeRES em Gest??o P??blica de acesso livre e da publica????o de livros sobre Gest??o de Pol??ticas P??blicas no Paran??, contendo artigos publicados pelos alunos sobre tem??ticas relacionadas ?? gest??o p??blica. Com isso, o Estado do Paran?? iniciou um processo de constru????o de saberes em gest??o p??blica a partir da reflex??o de suas pr??prias viv??ncias e experi??ncias, e de uma rela????o harmoniosa e inovadora entre produtores de saberes ??? a institui????o acad??mica e a administra????o p??blica ??? os quais criaram condi????es para a constru????o do conhecimento, o que n??o teria sido poss??vel de maneira isolada. Essa rede de conhecimento em pol??ticas p??blicas, por ter sido coletivamente constru??da, revelou que mais importante que o conhecimento em si e o processo da sua constru????o, foi a transposi????o desses resultados para a realidade n??o apenas dos produtores desse conhecimento, mas para todos os que atuam e s??o beneficiados pela gest??o p??blica

Curso: redes de pol??ticas p??blicas: o desafio da governan??a

O curso tem como objetivo apresentar as principais pol??ticas p??blicas implementadas pelos sistemas pol??ticos contempor??neos decorrentes de uma complexa e cont??nua intera????o entre diversos atores, tanto dentro quanto fora do governo.Nesse sentido, busca-se compreender a estrutura subjacente a essa intera????o, denominada rede de pol??ticas p??blicas. Assim, o curso discute as principais caracter??sticas destas redes, suas possibilidades e limita????es

Colet??nea de pol??ticas p??blicas: volume 2: redes de pol??tica p??blica

O principal objetivo deste livro ?? constituir uma fonte de pesquisa para o estudo do processo de produ????o e implementa????o de pol??ticas p??blicas. Por meio de textos selecionados, analisa-se o pr??prio conceito de pol??ticas p??blicas, discute-se as defini????es utilizadas para distinguir suas diversas fases e apresenta-se algumas das principais correntes te??ricas de an??lise sobre o processo de pol??ticas p??blicas.

A experi??ncia da Escola Nacional de Administra????o P??blica na articula????o de redes de capacita????o

Este artigo relata algumas das experi??ncias da ENAP como membro, articuladora e incentivadora da atua????o em rede entre institui????es voltadas ?? forma????o e ?? capacita????o de servidores p??blicos. ?? dado destaque ?? an??lise da experi??ncia da Rede Descentralizada de Capacita????o de gestores sociais, vivenciada em parceria com o Minist??rio do Desenvolvimento Social, no per??odo de 2007 e 2008. Ao final s??o apresentadas algumas contribui????es ?? reflex??o sobre os resultados dessas iniciativas.

Avalia????o de pol??ticas de financiamento a micro e pequenas empresas na gera????o de postos de trabalho: o caso do Proger ??? principais aspectos

O artigo se prop??e a apresentar os principais aspectos e resultados de uma nova metodologia de avalia????o de programas de financiamento a micro e pequenas empresas aplicada ao Programa de Gera????o de Emprego e Renda na ??rea urbana ??? Proger urbano, tanto no que se refere aos seus custos efetivos, at?? ent??o desconhecidos, quanto no que se refere ao seu impacto sobre a gera????o de empregos, estimado utilizando dados prim??rios oriundos do cruzamento de dois bancos de dados do Minist??rio do Trabalho e Emprego, quais sejam, o do Sistema de Acompanhamento da Execu????o do Proger (Saep), e o do Cadastro Geral de Empregados e Desempregados. S??o apresentados, preliminarmente, alguns dos resultados de duas avalia????es anteriores do programa, uma realizada pelo Ibase, atrav??s de question??rios aos benefici??rios do programa, e outra, uma primeira experi??ncia de cruzamento dos dois referidos bancos de dados, que serviu de base para a avalia????o que se apresenta.