Primary stabilization of humeral shaft fractures: an experimental study of different osteosynthesis methods

OBJETIVO: Estudo experimental idealizado com o objetivo de se avaliar a estabilização primária das fraturas da diáfise umeral com três diferentes métodos de osteossíntese, representados por uma placa tipo DCP aplicada com técnica em ponte, uma síntese incomum, denominada SPS®, ainda sem similar na literatura, aplicada pela técnica em ponte, e um terceiro método constituído de uma haste intramedular com um método de bloqueio também incomum proporcionado por um parafuso cortical distalmente e por um fio do tipo Ender proximalmente. MATERIAL E MÉTODO: Vinte e um pares de úmeros humanos foram divididos em três grupos, utilizando-se um tipo de material para cada grupo, os quais foram submetidos a osteotomias, aos procedimentos de fixação e a ensaios não destrutivos de flexo-compressão e de torção, com limites de carga de 200N e de 100N, respectivamente e, num mecanismo de "crossing", foram submetidos secundariamente a novos ensaios de torção e de flexo-compressão, amparados por análise estatística. RESULTADOS: O grupo da placa DCP em ponte mostrou boa resistência às cargas aplicadas, o que também ocorreu no grupo do SPS®, que apesar de mostrar maiores índices de deflexão, apresentou grande capacidade elástica. O grupo da haste intramedular mostrou bons resultados nos ensaios de flexo-compressão, devido ao seu mecanismo de tutor, mas não demonstrou resistência às cargas de torção.OBJECTIVE: The purpose of this study was to assess primary stabilization of humeral shaft fractures using three different methods of fixation, represented by a DCP type plate, applied as a bridge plate, an uncommon synthesis material named SPS®, not previously described in literature and also used as a bridge plate, and a third type of material constituted by an intramedullary nail, with an uncommon locking provided by a distal cortical screw and a proximal Ender-type wire. MATERIAL AND METHOD: Twenty-one pairs of human humeri were divided into three groups, each using one type of material for fixation, the bones of which were osteotomized, stabilized and submitted to nondestructive flexion-compression and torsion assays up to 200 N and 100 N respectively, and, in a crossing mechanism, the groups were again submitted to other torsion and flexion-compression assays, supported by statistical analysis. RESULTS: The bridge-DCP group showed good resistance to the applied forces, similarly to the SPS® group, which, although presenting greater deflection, showed great elastic capacity. The intramedullary nail group showed good results in the flexion-compression assay due to the tutor mechanism of the intramedullary nails, but did not show resistance to the torsion forces

CUTTING TYPES AND SUBSTRATES FOR JAMBOLÃO ADVENTITIOUS ROOTING

O presente trabalho teve por objetivo avaliar os tipos de estaca e diferentes substratos no enraizamento de jambolão. Estacas caulinares apicais, medianas e basais foram confeccionadas a partir de ramos semilenhosos, com 12 cm de comprimento, mantendo-se um par de folhas reduzidas à metade. O plantio foi realizado em tubetes de polipropileno (53 cm3) contendo vermiculita de granulometria fina ou Plantmax HT® e caixas plásticas contendo areia de granulometria média como substrato. As estacas foram mantidas em casa-de-vegetação com nebulização intermitente e, após 120 dias do plantio, foram avaliadas as variáveis porcentagem de estacas enraizadas, com calos, vivas (não enraizadas e sem calos) e mortas, comprimento das três maiores raízes (cm) e número de raízes formadas por estaca. O melhor enraizamento foi verificado na areia (55,00%), quando comparado ao Plantmax HT® (31,25%) e à vermiculita (13,75%), com estacas da posição mediana do ramo, sendo também observada a menor mortalidade. Em relação ao número e ao comprimento médio de raízes, o Plantmax HT® foi numericamente superior aos demais. Dentre os tipos de estaca e os substratos utilizados no experimento, pode-se inferir que o jambolão pode ser propagado por meio de estacas medianas no substrato areia.The purpose of this work was to evaluate the effect of the kinds of cuttings and substrates in Syzygium cumini adventitious rooting. Caulinar cuttings were prepared from apical, medium and basal parts of semi-hardwood branches, 12 cm long, with one pair of half-cut leaves. They were then planted in polypropylene tubes containing fine vermiculite or Plantmax HT® substrate or in plastic boxes containing sand. The cuttings were kept in greenhouse under intermittent mist and after 120 days were evaluated: the number of rooted cuttings, number of cuttings containing callus, alive (not rooted and without callus) and dead cuttings, length of the three biggest roots and number of roots per cutting. Better rooting was obtained in sand (55,00%), while Plantmax HT® substrate was 31,25% and vermiculite was 13,75%, in cuttings of the branch middle portion. The death of cuttings was the lowest in sand and in this portion. The number and mean length of roots were higher in Plantmax HT® substrate. This study showed that Syzygium cumini can be propagated by cuttings from the middle part of the branches rooted in sand

Seroprevalence and Seroconversion of Dengue and Implications for Clinical Diagnosis in Amazonian Children

This study aimed to evaluate the prevalence of serum IgG dengue in children in an Amazonian population, to assess the seroconversion rate in 12 months, and to estimate how many seropositive children had a prior clinical diagnosis of dengue. We conducted a population-based study between 2010 and 2011, with children aged 6 months to 12 years that were living in the urban area of a small town in the Brazilian Amazon. The prevalence of IgG antibodies against dengue antigens was determined by indirect ELISA technique, and seronegative children were reexamined after 12 months to determine seroconversion rates. Results showed seroprevalence of IgG antibodies against dengue type of 2.9%, with no significant association between age, race, and sex. In seropositive children, only 8.4% had received a clinical diagnosis of dengue, and the ratio of clinically diagnosed cases and subclinical cases was 1 : 11. The seroconversion rate between 2010 and 2011 was 1.4% (CI 3.8% to 35.1%). The seroprevalence of dengue in this pediatric population was low, and the vast majority of cases were not clinically detected, suggesting a difficulty in making the clinical diagnosis in children and a high frequency of asymptomatic infections

A Lagrangian Description of Buoyancy Effects on Aircraft Wake Vortices from Wing Tips near a Heated Ground Plane

The present paper introduces the key ideas of a purely Lagrangian temperature particle method, which includes preheating effects on fluid flow nearest a heated wall. The numerical approach is then applied for the study of mixed heat transfer on aircraft wake vortices from wing tips in the vicinity of a heated ground plane, a situation commonly found during landing or takeoff operations at airports around the world. It was found in the literature experimental results of an investigation without the effects of heat transfer and crosswind, which were useful for a comparison with some present numerical results. Other numerical results are also discussed, focusing on the physics of the effects of mixed convection heat transfer and crosswind. As a contribution, the Richardson number is defined in terms of both aircraft wingspan and constant ground plane temperature, being the most important dimensionless group to capture the effects of laminar ascending mixed convection flow. The present methodology presents potentialities for predicting the transport and decay of primary vortical structures (under buoyancy forces), including their interaction with secondary vortical structures generated from a ground plane

Control and Suppression of Vortex Shedding from a Slightly Rough Circular Cylinder by a Discrete Vortex Method

A discrete vortex method is implemented with a hybrid control technique of vortex shedding to solve the problem of the two-dimensional flow past a slightly rough circular cylinder in the vicinity of a moving wall. In the present approach, the passive control technique is inspired on the fundamental principle of surface roughness, promoting modifications on the cylinder geometry to affect the vortex shedding formation. A relative roughness size of ε*/d* = 0.001 (ε* is the average roughness and d* is the outer cylinder diameter) is chosen for the test cases. On the other hand, the active control technique uses a wall plane, which runs at the same speed as the free stream velocity to contribute with external energy affecting the fluid flow. The gap-to-diameter varies in the range from h*/d* = 0.05 to 0.80 (h* is the gap between the moving wall and the cylinder bottom). A detailed account of the time history of pressure distributions, simultaneously investigated with the time evolution of forces, Strouhal number behavior, and boundary layer separation are reported at upper-subcritical Reynolds number flows of Re = 1.0 × 105. The saturation state of the numerical simulations is demonstrated through the analysis of the Strouhal number behavior obtained from temporal history of the aerodynamic loads. The present work provides an improvement in the prediction of Strouhal number than other studies no using roughness model. The aerodynamic characteristics of the cylinder, as well as the control of intermittence and complete interruption of von Kármán-type vortex shedding have been better clarified