One stage procedure for developmental dysplasia of the hip in patients aged eight years or older. Systematic review and meta-analysis.

The objective of the present study is to perform a systematic review with meta-analysis of the literature on treatment of developmental dysplasia of the hip (DDH) in patients over eight years of age to provide better understanding of therapeutic strategies and results. Authors carried out a systematic review and metanalysis of the literature on DDH treated in patients aged eight years of age or older. A literature search was carefully performed from June 2019 to June 2020. The articles had to report one stage reconstructive surgical treatment of DDH for patients eight years or older, presenting clinical and radiographic evaluation according to the Tonnis and Severin, and McKay systems. Meta-analysis was carried out using the software metanalyst to perform the pooled effect size Nine studies met the inclusion criteria. They assessed a total of 234 patients and 266 hips. Female patients accounted for 75.7% (eight unknown) and the follow-up ranged from 1 to 17.4 years. The majority of the procedures included an acetabular surgery (93.9%) while femoral shortening was performed in 78%. Acceptable outcomes were found in between 67% (Mckay system) and 91% (Severin system) of the cases. Femoral varus and derrotation shortening associated with redirectional osteotomy of the acetabulum (for those with closed triradiate cartilage) or acetabular redirection/reshaping were the most prevalent combined procedures; this strategy can lead to 60% of acceptable clinical results and 90% of radiographically acceptable results. Therefore, our findings give credence to the recommendation for the treatment of DDH in patients over eight years old.

Interaction between a robot and Bunimovich stadium billiards.

The robot-environment-task triad provides many opportunities to revisit physical problems with fresh eyes. Hence, we develop a simple experiment to observe chaos in classical billiards with a macroscopic 3.38-m long setup. Using a digital video camera, one records the dynamic time evolution of the interaction between a robot and Bunimovich stadium billiards with specular reflection. From the experimental time series, we calculate the Lyapunov exponent [Formula: see text] as a function of a geometric parameter. The results are in concordance with theoretical predictions. In addition, we determine the Poincaré surface of section from the experimental data and check its sensitivity to the initial conditions as a function of time.

Lyapunov exponent in the Vicsek model.

The well-known Vicsek model describes the dynamics of a flock of self-propelled particles (SPPs). Surprisingly, there is no direct measure of the chaotic behavior of such systems. Here we discuss the dynamical phase transition present in Vicsek systems in light of the largest Lyapunov exponent (LLE), which is numerically computed by following the dynamical evolution in tangent space for up to two million SPPs. As discontinuities in the neighbor weighting factor hinder the computations, we propose a smooth form of the Vicsek model. We find a chaotic regime for the collective behavior of the SPPs based on the LLE. The dependence of LLE with the applied noise, used as a control parameter, changes sensibly in the vicinity of the well-known transition points of the Vicsek model.

Gastric lesions in free-ranging black caimans (Melanosuchus niger) associated with Brevimulticaecum species.

The stomachs of 100 free-ranging black caimans (Melanosuchus niger Spix, 1825) from the Mamirauá Sustainable Development Reserve, Amazonas state, Brazil, were examined for parasitism and pathologic lesions. All animals were harvested for human consumption. Ascaridoid nematodes were found in 67 caimans and were identified as Brevimulticaecum sp. These parasites were associated with focally extensive, chronic gastric ulcers and formation of localized intramural granulomas containing nematodes. All caiman were in good nutritional condition, which suggests that effects of gastric nematodiasis on the crocodilian hosts were minimal at the time of slaughter.

Fractality of largest clusters and the percolation transition in power-law diluted chains.

Relying on the fractal character of the largest clusters at criticality, we employ a finite-size scaling analysis to obtain an accurate phase-diagram of the percolation transition in chains with bond concentration decaying as a power-law on the form 1/ r(1+sigma) . For the particular case of sigma=1, no percolation transition is observed to occur at a finite dilution, in contrast with the finite temperature Kosterlitz-Thouless transition exhibited in Ising and Potts chains with inverse square-law couplings. The fractal dimension of the critical percolation cluster is found to follow distinct dependencies on the decay exponent being numerically fitted by d(f) =0.35+4sigma/5 for 0

Influence of treatment with immunosuppressive drugs in mice chronically infected with Trypanosoma cruzi.

Latent Trypanosoma cruzi infection may be reactivated in immunosuppressed individuals, with unusual clinical patterns, such as meningoencephalitis, pseudo neoplastic lesions in the central nervous system, and myocarditis with numerous parasites in the heart muscle. To investigate this problem 68 Swiss mice chronically infected with different strains of T. cruzi were treated with different combinations of immunosuppressive drugs (azathioprine, cyclosporine and betamethasone), in such a way as to imitate the situation during post transplantation treatment. Mortality varied from 6 to 25% in treated mice. There were no deaths in untreated controls. Normal mice have been submitted to the same schedules of immunosuppression as controls of treatment and no deaths were registered during treatment. Chronically infected mice showed significant elevation of total number of leukocytes and lymphocytes in comparison with intact controls; a significant decrease in blood leukocytes and lymphocytes occurred post-treatment in two of the treated experimental groups. Exacerbation of myocarditis and myositis and a high incidence of brain lesions, with focal necrosis, granulomatous lesions and glial proliferation even in the absence of parasites were present in immunosuppressed mice but not in infected controls. Although differing in some aspects from Chagas' disease in immunosuppressed humans, the murine model did show some features that resembled it, especially the peculiar pattern of central nervous system involvement.