Anatomical study of the lateral patellofemoral ligament in cadaver knees

OBJECTIVES: To describe the lateral patellofemoral ligament (LPFL) after anatomical dissection of fresh cadaver knees. The literature shows a particular interest for the LPFL. Such special attention is due to its anatomical and biomechanical importance, and also due to the need to reconstruct the ligament in the cases of medial patellar instability. METHODS: The LPFL was studied in 20 knees of 20 fresh cadavers by means of anatomical dissections. The dissections were standardized and the data were noted down and forwarded to statistical analysis. RESULTS: The LPFL presented a mean 16.05 mm width (standard deviation of 2.48), 42.10 mm length (standard deviation of 8.84). The femoral insertion was found at the lateral femoral epicondyle and with a fan-like expansion of the fibers, predominantly in the posterior region proximal to the lateral epicondyle. In the patella, the insertion found was in the upper-lateral region (in the middle of the upper third of the coronal plan), also with expanded fibers, but less intensely so. In the sagittal plan, the ligament was located in the posterior half of the border of the patella. The LPFL was isolated in the second lateral retinacular layer, the deep transverse retinaculum. CONCLUSION: The LPFL is located in the deep transverse retinacular layer with the presence of a fan-like expansion of its fibers both in the femoral and in the patellar insertions. The insertion is more posterior and proximal at the femoral epicondyle and in the posterior half of the patellar border (sagittal plan) and in the upper-lateral aspect.OBJETIVOS: Descrever o ligamento patelofemoral lateral (LPFL) por meio de dissecação anatômica de joelhos de cadáveres frescos. Na literatura existe particular interesse pelo LPFL. Essa especial atenção é dada pela sua importância anatômica, biomecânica e pela necessidade da sua reconstrução nos casos de instabilidade medial da patela. MÉTODOS: O LPFL foi estudado em 20 joelhos de 20 cadáveres frescos por meio de dissecações anatômicas. As dissecações foram padronizadas e os dados anotados enviados para análise estatística. RESULTADOS: O LPFL apresentou em média 16,05mm de largura (desvio-padrão: 2,48), 42,10mm de comprimento (desvio-padrão: 8,84). Sua inserção femoral mostrou-se no epicôndilo femoral lateral e com expansão em forma de leque das suas fibras, predominantemente na região posterior e proximal ao epicôndilo lateral. Na patela a inserção encontrada foi na região súpero-lateral (na metade do terço superior no plano coronal), também com expansão das fibras, mas com menor intensidade. No plano sagital, o ligamento situava-se na metade posterior da borda da patela. O LPFL foi isolado na segunda camada retinacular lateral, o retináculo transverso profundo. CONCLUSÃO: O LPFL situa-se na camada retinacular transversa profunda, com a presença de uma expansão das suas fibras em forma de leque, tanto na inserção femoral quanto na patelar. No epicôndilo femoral a inserção encontra-se mais posterior e proximalmente e na patela está na metade posterior da borda patelar (plano sagital) e no aspecto súpero-lateral.Faculdade de Medicina do ABC Grupo de Traumatologia Esportiva da Disciplina de OrtopediaUNIFESP Departamento de OrtopediaFaculdade de Medicina do ABCUNIFESP, Depto. de OrtopediaSciEL

Randomized prospective study comparing transverse and extracortical fixation in anterior cruciate ligament reconstruction

OBJECTIVE: This study had the objective of prospectively comparing transverse fixation (Cross-PinTM) with extracortical fixation (EZLocTM) for the femur, in surgical reconstruction of the anterior cruciate ligament, from a clinical, biomechanical and functional point of view. METHODS: Between April 2007 and November 2009, 50 patients with acute or chronic anterior cruciate ligament injuries underwent arthroscopic reconstruction using the homologous flexor tendons (gracilis and semitendinosus). Randomization of the femoral fixation method was done by means of a draw at the time of the procedure. Patients were excluded if they presented multiple ligament lesions, fractures, previous surgery, autoimmune disease and impairment of the contralateral knee. The Lysholm scale, SF36 quality-of-life questionnaire and KT1000TM arthrometer were used. RESULTS: After a mean follow-up of 18.1 months, there were no statistically significant differences between the groups regarding the Lysholm scale and KT1000TM measurements. However, the SF36 questionnaire showed a statistical difference such that transverse fixation was superior regarding pain and vitality. CONCLUSION: Both techniques were shown to be efficient for transfemoral fixation, but with almost no statistically significant difference between them. We believe that new studies will be necessary for better understanding of these differences.OBJETIVO: Comparar prospectivamente as fixações transversas (Cross-PinTM) com as extracorticais (EZLocTM) no fêmur nas reconstruções cirúrgicas do ligamento cruzado anterior sob o ponto de vista clínico, biomecânico e funcional. MÉTODOS: Entre abril de 2007 e novembro de 2009, 50 pacientes com lesões do ligamento cruzado anterior, agudas e crônicas, foram submetidos à reconstrução por abordagem artroscópica utilizando os tendões flexores homólogos (grácil e semitendíneo). A randomização do método de fixação femoral ocorreu por meio de sorteio no momento da cirurgia. Excluímos os pacientes portadores de lesões ligamentares múltiplas, fraturas, cirurgias prévias, doenças autoimunes e comprometimento do membro contralateral. Foram utilizadas as escalas de Lysholm, o questionário qualidade de vida SF-36 e o artrômetro KT-1000TM. RESULTADOS: Após 18,1 meses, em média, não foram observadas diferenças estatisticamente significantes entre os grupos quanto utilizadas as escalas de Lysholm e as medidas do KT-1000TM. Quanto aos resultados do SF-36, observamos diferença significante com superioridade da fixação transversa considerando a dor e a vitalidade. CONCLUSÃO: As duas técnicas mostraram ser eficientes na fixação transfemoral com tendões flexores, porém quase sem nenhuma diferença estatística significante. Entendemos que novos estudos serão necessários para melhor entendimento dessas diferenças.Hospital IFORUniversidade Federal de São Paulo (UNIFESP) Departamento de Ortopedia e Traumatologia Grupo do JoelhoFaculdade de Medicina do ABC Grupo de Traumatologia EsportivaUNIFESP, Depto. de Ortopedia e Traumatologia Grupo do JoelhoSciEL

C^2-Ray: A new method for photon-conserving transport of ionizing radiation

We present a new numerical method for calculating the transfer of ionizing radiation, called C^2-Ray=Conservative, Causal Ray-tracing method. The method is explicitly photon-conserving, so the depletion of ionizing photons by bound-free opacity is guaranteed to equal the photoionizations these photons caused. As a result, grid cells can be large and very optically-thick without loss of accuracy. The method also uses an analytical relaxation solution for the ionization rate equations for each time step which can accommodate time steps which greatly exceed the characteristic ionization and ionization front crossing times. Together, these features make it possible to integrate the equation of transfer along a ray with many fewer cells and time steps than previous methods. For multi-dimensional calculations, the code utilizes short-characteristics ray tracing. C^2-Ray is well-suited for coupling radiative transfer to gas and N-body dynamics methods, on both fixed and adaptive grids, without imposing additional limitations on the time step and grid spacing. We present several tests of the code involving propagation of ionization fronts in one and three dimensions, in both homogeneous and inhomogeneous density fields. We compare to analytical solutions for the ionization front position and velocity, some of which we derive here for the first time.Comment: 40 pages, 22 figures, to appear in New Astronomy. Updated version after Comments from the referee. Movies associated with this paper can be obtained at http://www.strw.leidenuniv.nl:/~mellema/Reionization/c2ray.htm

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Production of He-4 and (4) in Pb-Pb collisions at root(NN)-N-S=2.76 TeV at the LHC

Results on the production of He-4 and (4) nuclei in Pb-Pb collisions at root(NN)-N-S = 2.76 TeV in the rapidity range vertical bar y vertical bar <1, using the ALICE detector, are presented in this paper. The rapidity densities corresponding to 0-10% central events are found to be dN/dy4(He) = (0.8 +/- 0.4 (stat) +/- 0.3 (syst)) x 10(-6) and dN/dy4 = (1.1 +/- 0.4 (stat) +/- 0.2 (syst)) x 10(-6), respectively. This is in agreement with the statistical thermal model expectation assuming the same chemical freeze-out temperature (T-chem = 156 MeV) as for light hadrons. The measured ratio of (4)/He-4 is 1.4 +/- 0.8 (stat) +/- 0.5 (syst). (C) 2018 Published by Elsevier B.V.Peer reviewe

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Hyperoxemia and excess oxygen use in early acute respiratory distress syndrome : Insights from the LUNG SAFE study

Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Concerns exist regarding the prevalence and impact of unnecessary oxygen use in patients with acute respiratory distress syndrome (ARDS). We examined this issue in patients with ARDS enrolled in the Large observational study to UNderstand the Global impact of Severe Acute respiratory FailurE (LUNG SAFE) study. Methods: In this secondary analysis of the LUNG SAFE study, we wished to determine the prevalence and the outcomes associated with hyperoxemia on day 1, sustained hyperoxemia, and excessive oxygen use in patients with early ARDS. Patients who fulfilled criteria of ARDS on day 1 and day 2 of acute hypoxemic respiratory failure were categorized based on the presence of hyperoxemia (PaO2 > 100 mmHg) on day 1, sustained (i.e., present on day 1 and day 2) hyperoxemia, or excessive oxygen use (FIO2 ≥ 0.60 during hyperoxemia). Results: Of 2005 patients that met the inclusion criteria, 131 (6.5%) were hypoxemic (PaO2 < 55 mmHg), 607 (30%) had hyperoxemia on day 1, and 250 (12%) had sustained hyperoxemia. Excess FIO2 use occurred in 400 (66%) out of 607 patients with hyperoxemia. Excess FIO2 use decreased from day 1 to day 2 of ARDS, with most hyperoxemic patients on day 2 receiving relatively low FIO2. Multivariate analyses found no independent relationship between day 1 hyperoxemia, sustained hyperoxemia, or excess FIO2 use and adverse clinical outcomes. Mortality was 42% in patients with excess FIO2 use, compared to 39% in a propensity-matched sample of normoxemic (PaO2 55-100 mmHg) patients (P = 0.47). Conclusions: Hyperoxemia and excess oxygen use are both prevalent in early ARDS but are most often non-sustained. No relationship was found between hyperoxemia or excessive oxygen use and patient outcome in this cohort. Trial registration: LUNG-SAFE is registered with ClinicalTrials.gov, NCT02010073publishersversionPeer reviewe

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost