38 research outputs found
Values - reviewing the construct and drawing implications for values work in organisation and leadership. Kap. 2
I: H.Askeland, G. Espedal, B. Jelstad Løvaas & S. Sirris (Eds.), Understanding values work : Institutional perspectives in organizations and leadershipThis chapter outlines the trajectory of values, particularly within streams of organisational institutionalism, in order to analyse its application to values work in organisation and leadership. Conveying a frame for discussing values work, it aims at clarifying how to conceptualise the term values. Discussing classic and recent contributions, the chapter proposes seeing values as individual and collective conceptions of desirable trans-situational behaviours, objectives and ideals, serving to guide or valuate practice. Despite being an essential part of defining organisational institutionalism, and its sub-streams, values are seldom explicated. Utilising values in organisational and leadership research requires attention to their situatedness in contexts, and this chapter argues they are salient to organisations operating in pluralistic institutional environment. Studying values work, attention should be given to who and how such work is performed.publishedVersio
Biological evaluation of alginate-based hydrogels, with antimicrobial features by Ce(III) incorporation, as vehicles for a bone substitute
In this work three different hydrogels were developed to associate, as vehicles, with the synthetic bone substitute GR-HA. One based on an alginate matrix (Alg); a second on a mixture of alginate and chitosan (Alg/Ch); and a third on alginate and hyaluronate (Alg/HA), using Ca2+ ions as cross-linking agents. The hydrogels, as well as the respective injectable bone substitutes (IBSs), were fully characterized from the physical-chemical point of view. Weight change studies proved that all hydrogels were able to swell and degrade within 72 hours at pH 7.4 and 4.0, being Alg/HA the hydrogel with the highest degradation rate (80%). Rheology studies demonstrated that all hydrogels are non-Newtonian viscoelastic fluids, and injectability tests showed that IBSs presented low maximum extrusion forces, as well as quite stable average forces. In conclusion, the studied hydrogels present the necessary features to be successfully used as vehicles of GR-HA, particularly the hydrogel Alg/HA.The authors would like to acknowledge the financial support from FCT (Fundacao para a Ciencia e a Tecnologia) through the grant SFRH/BD/76237/2011 and project ENMED/0002/2010, from FEDER funds through the program COMPETE-Programa Operacional Factores de Competitividade-under the project PEst-C/EME/UI0285/2011, as well as to the project I&DT BIOMAT&CELL n. 1372
Delayed surgical treatment for a traumatic bilateral cervical facet joint dislocation using a posterior-anterior approach: a case report
<p>Abstract</p> <p>Introduction</p> <p>There have been few reports of patients with bilateral cervical facet dislocations that remain untreated for eight weeks or more. We report the case of a 76-year-old man with an old bilateral cervical facet joint dislocation fracture that was treated by posterior-anterior reduction and fixation.</p> <p>Case presentation</p> <p>A 76-year-old Asian man was involved in a road traffic accident. He presented with neck pain and arm pain on his right side, but motor weakness and paralysis were not observed. He was treated conservatively; however, instability and spondylolisthesis at the C5 to C6 joint increased eight weeks after the injury. We performed a posterior-anterior reduction and fixation. After surgery, bony union was achieved, and his neck pain and arm pain disappeared.</p> <p>Conclusion</p> <p>We recommend reduction and fixation surgery if a patient has an old bilateral facet joint dislocation fracture in the cervical spine.</p
Análise fotoelástica de parafuso de sistema de fixação vertebral The photoelastic analisys of vertebral fixation system screws
INTRODUÇÃO: A fotoelasticidade é utilizada para avaliar as tensões/deformações produzidas nos materiais fotoelásticos, quando submetidos a determinado carregamento, através da observação de efeitos óticos. O desempenho do parafuso e as funções mecânicas estão diretamente relacionados com a qualidade da fixação dos parafusos nas vértebras. A fotoelasticidade é uma ferramenta importante para realizar estudos comparativos desta natureza. OBJETIVO: O objetivo deste estudo foi comparar por meio da fotoelasticidade, as tensões internas produzidas pelo parafuso com 6 mm de diâmetro externo, quando submetido a duas diferentes forças de arrancamento. MATERIAIS E MÉTODOS: Para isso, foram confeccionados quatro modelos fotoelásticos. A simulação foi realizada utilizando duas forças de arrancamento 0,75 e 1,50 kgf. As tensões cisalhantes foram calculadas nos 19 pontos em torno dos parafusos, utilizando o método de compensação de Tardy. RESULTADOS: Os valores das tensões cisalhantes foram maiores quando utilizada a força de arrancamento de 1,50 kgf. CONCLUSÃO: Assim sendo, o parafuso estará mais suscetÃvel ao arrancamento com a aplicação de força de maior intensidade. De acordo com as análises realizadas verificamos também que o local de maior tensão cisalhante foi observado no pico das cristas, principalmente próxima à s pontas dos parafusos, independente da força utilizada.<br>INTRODUCTION: The photoelasticity is used for assessing the tensions/deformations involved in photoelastic materials when submitted to a given load by the observation of optical effects. The screw performance and mechanical functions are directly associated to the quality of the screws fixation in the vertebrae. Photoelasticity is an important tool to perform comparative studies of this nature OBJECTIVE: The aim of this study was to compare, by using photoelasticity, internal stresses produced by the screw with an external diameter of 6 mm, when submitted to two different pullout strengths. MATERIALS AND METHODS: For this, four photoelastic models were produced. The simulation was conducted by using two pullout strengths: 0.75 and 1.50 kgf. The maximum shear stresses were calculated on 19 points around the screws, using the Tardy compensation method. RESULTS: The values of maximum shear stress were higher with the load of 1.50 kgf. CONCLUSION: Thus, the screw will be more susceptible to pullout when heavier loads are applied. According to our analysis, we also found that the site with the highest maximum shear stress was found to be at the peak of creast, particularly near the tips of the screws, regardless of the load employed