384 research outputs found

    The influence of knee position on ankle dorsiflexion - a biometric study

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    Background: Musculus gastrocnemius tightness (MGT) can be diagnosed by comparing ankle dorsiflexion (ADF) with the knee extended and flexed. Although various measurement techniques exist, the degree of knee flexion needed to eliminate the effect of the gastrocnemius on ADF is still unknown. The aim of this study was to identify the minimal degree of knee flexion required to eliminate the restricting effect of the musculus gastrocnemius on ADF. Methods: Bilateral ADF of 20 asymptomatic volunteers aged 18-40 years (50% female) was assessed prospectively at six different degrees of knee flexion (0 degrees, 20 degrees, 30 degrees, 45 degrees, 60 degrees, 75 degrees, Lunge). Tests were performed following a standardized protocol, non weightbearing and weightbearing, by two observers. Statistics comprised of descriptive statistics, t-tests, repeated measurement ANOVA and ICC. Results: 20 individuals with a mean age of 27 +/- 4 years were tested. No significant side to side differences were observed. The average ADF [95% confidence interval] for non weightbearing was 4 degrees{[}1 degrees-8 degrees] with the knee extended and 20 degrees [16 degrees-24 degrees] for the knee 75 flexed. Mean weightbearing ADF was 25 degrees[22 degrees-28 degrees] for the knee extended and 39 degrees[36 degrees-42 degrees] for the knee 75 degrees flexed. The mean differences between 20 degrees knee flexion and full extension were 15 degrees[12 degrees-18 degrees] non weightbearing and 13 degrees[11 degrees-16 degrees] weightbearing. Significant differences of ADF were only found between full extension and 20 degrees of knee flexion. Further knee flexion did not increase ADF. Conclusion: Knee flexion of 20 degrees fully eliminates the ADF restraining effect of the gastrocnemius. This knowledge is essential to design a standardized clinical examination assessing MGT

    The influence of distal screw length on the primary stability of volar plate osteosynthesis-a biomechanical study

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    Background: Extensor tendon irritation is one of the most common complications following volar locking plate osteosynthesis (VLPO) for distal radius fractures. It is most likely caused by distal screws protruding the dorsal cortex. Shorter distal screws could avoid this, yet the influence of distal screw length on the primary stability in VLPO is unknown. The aim of this study was to compare 75 to 100 % distal screw lengths in VLPO. Methods: A biomechanical study was conducted on 11 paired fresh-frozen radii. HRpQCT scans were performed to assess bone mineral density (BMD) and bone mineral content (BMC). The specimens were randomized pair-wise into two groups: 100 % (group A) and 75 % (group B) unicortical distal screw lengths. A validated fracture model for extra-articular distal radius fractures (AO-23 A3) was used. Polyaxial volar locking plates were mounted, and distal screws was inserted using a drill guide block. For group A, the distal screw tips were intended to be flush or just short of the dorsal cortex. In group B, a target screw length of 75 % was calculated. The specimens were tested to failure using a displacement-controlled axial compression test. Primary biomechanical stability was assessed by stiffness, elastic limit, and maximum force as well as with residual tilt, which quantified plastic deformation. Results: Nine specimens were tested successfully. BMD and BMC did not differ between the two groups. The mean distal screw length of group A was 21.7 +/- 2.6 mm (range: 16 to 26 mm),for group B 16.9 +/- 1.9 mm (range: 12 to 20 mm). Distal screws in group B were on average 5.6 +/- 0.9 mm (range: 3 to 7 mm) shorter than measured. No significant differences were found for stiffness (706 +/- 103 N/mm vs. 660 +/- 124 N/mm),elastic limit (177 +/- 25 N vs. 167 +/- 36 N),maximum force (493 +/- 139 N vs. 471 +/- 149 N),or residual tilt (7.3 degrees +/- 0.7 degrees vs. 7.1 degrees +/- 1.3 degrees). Conclusion: The 75 % distal screw length in VLPO provides similar primary stability to 100 % unicortical screw length. This study, for the first time, provides the biomechanical basis to choose distal screws significantly shorter then measured

    The influence of distal screw length on the primary stability of volar plate osteosynthesis-a biomechanical study

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    Background: Extensor tendon irritation is one of the most common complications following volar locking plate osteosynthesis (VLPO) for distal radius fractures. It is most likely caused by distal screws protruding the dorsal cortex. Shorter distal screws could avoid this, yet the influence of distal screw length on the primary stability in VLPO is unknown. The aim of this study was to compare 75 to 100 % distal screw lengths in VLPO. Methods: A biomechanical study was conducted on 11 paired fresh-frozen radii. HRpQCT scans were performed to assess bone mineral density (BMD) and bone mineral content (BMC). The specimens were randomized pair-wise into two groups: 100 % (group A) and 75 % (group B) unicortical distal screw lengths. A validated fracture model for extra-articular distal radius fractures (AO-23 A3) was used. Polyaxial volar locking plates were mounted, and distal screws was inserted using a drill guide block. For group A, the distal screw tips were intended to be flush or just short of the dorsal cortex. In group B, a target screw length of 75 % was calculated. The specimens were tested to failure using a displacement-controlled axial compression test. Primary biomechanical stability was assessed by stiffness, elastic limit, and maximum force as well as with residual tilt, which quantified plastic deformation. Results: Nine specimens were tested successfully. BMD and BMC did not differ between the two groups. The mean distal screw length of group A was 21.7 +/- 2.6 mm (range: 16 to 26 mm),for group B 16.9 +/- 1.9 mm (range: 12 to 20 mm). Distal screws in group B were on average 5.6 +/- 0.9 mm (range: 3 to 7 mm) shorter than measured. No significant differences were found for stiffness (706 +/- 103 N/mm vs. 660 +/- 124 N/mm),elastic limit (177 +/- 25 N vs. 167 +/- 36 N),maximum force (493 +/- 139 N vs. 471 +/- 149 N),or residual tilt (7.3 degrees +/- 0.7 degrees vs. 7.1 degrees +/- 1.3 degrees). Conclusion: The 75 % distal screw length in VLPO provides similar primary stability to 100 % unicortical screw length. This study, for the first time, provides the biomechanical basis to choose distal screws significantly shorter then measured

    Spectroscopy of 35^{35}P using the one-proton knockout reaction

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    The structure of 35^{35}P was studied with a one-proton knockout reaction at88~MeV/u from a 36^{36}S projectile beam at NSCL. The γ\gamma rays from thedepopulation of excited states in 35^{35}P were detected with GRETINA, whilethe 35^{35}P nuclei were identified event-by-event in the focal plane of theS800 spectrograph. The level scheme of 35^{35}P was deduced up to 7.5 MeV usingγγ\gamma-\gamma coincidences. The observed levels were attributed to protonremovals from the sdsd-shell and also from the deeply-bound p_1/2p\_{1/2} orbital.The orbital angular momentum of each state was derived from the comparisonbetween experimental and calculated shapes of individual (γ\gamma-gated)parallel momentum distributions. Despite the use of different reactions andtheir associate models, spectroscopic factors, C2SC^2S, derived from the36^{36}S (1p)(-1p) knockout reaction agree with those obtained earlier from36^{36}S(dd,\nuc{3}{He}) transfer, if a reduction factor R_sR\_s, as deducedfrom inclusive one-nucleon removal cross sections, is applied to the knockout transitions.In addition to the expected proton-hole configurations, other states were observedwith individual cross sections of the order of 0.5~mb. Based on their shiftedparallel momentum distributions, their decay modes to negative parity states,their high excitation energy (around 4.7~MeV) and the fact that they were notobserved in the (dd,\nuc{3}{He}) reaction, we propose that they may resultfrom a two-step mechanism or a nucleon-exchange reaction with subsequent neutronevaporation. Regardless of the mechanism, that could not yet be clarified, thesestates likely correspond to neutron core excitations in \nuc{35}{P}. Thisnewly-identified pathway, although weak, offers the possibility to selectivelypopulate certain intruder configurations that are otherwise hard to produceand identify.Comment: 5 figures, 1 table, accepted for publication in Physical Review

    Federated Learning Based Proactive Content Caching in Edge Computing

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    This is the author accepted manuscript. the final version is available from IEEE via the DOI in this recordContent caching is a promising approach in edge computing to cope with the explosive growth of mobile data on 5G networks, where contents are typically placed on local caches for fast and repetitive data access. Due to the capacity limit of caches, it is essential to predict the popularity of files and cache those popular ones. However, the fluctuated popularity of files makes the prediction a highly challenging task. To tackle this challenge, many recent works propose learning based approaches which gather the users' data centrally for training, but they bring a significant issue: users may not trust the central server and thus hesitate to upload their private data. In order to address this issue, we propose a Federated learning based Proactive Content Caching (FPCC) scheme, which does not require to gather users' data centrally for training. The FPCC is based on a hierarchical architecture in which the server aggregates the users' updates using federated averaging, and each user performs training on its local data using hybrid filtering on stacked autoencoders. The experimental results demonstrate that, without gathering user's private data, our scheme still outperforms other learning-based caching algorithms such as m-epsilon-greedy and Thompson sampling in terms of cache efficiency.Engineering and Physical Sciences Research Council (EPSRC)National Key Research and Development Program of ChinaNational Natural Science Foundation of ChinaEuropean Union Seventh Framework Programm

    Medida da proteína S-100B sérica para classificação de risco no trauma craniano leve: estudo piloto no Brasil

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    BACKGROUND: Release of the neuronal protein S-100B into the circulation has been suggested as a specific indication of neuronal damage. The hypothesis that S-100B is a useful and cost-effective screening tool for the management of minor head injuries was tested. METHODS: Fifty consecutive patients sustaining isolated minor head injury were prospectively evaluated in the emergency room of a Brazilian hospital by routine cranial computed tomography scan. Venous blood samples (processed to serum) were assssayed for S-100B using a newly developed immunoassay test kit. Twenty-one normal healthy individuals served as negative controls. Data are presented as median and 25 to 75 percentiles. RESULTS: Patients reached the emergency room an average of 45 minutes (range: 30-62 minutes) after minor head injury. Six of 50 patients (12%) showed relevant posttraumatic lesions in the initial cranial computed tomography scan and were counted as positive. The median systemic concentration of S-100B in those patients was 0.75 µg/L (range: 0.66-6.5 µg/L), which was significantly different (U-test, P < .05) from the median concentration of 0.26 µg/L (range: 0.12-0.65 µg/L), of patients without posttraumatic lesions as counted by the cranial computed tomography. A sensitivity of 100%, a specificity of 20%, a positive predictive value of 15%, and a negative predictive value of 100% was calculated for the detection of patients suffering from intracranial lesions. CONCLUSIONS: Protein S-100B had a very high sensitivity and negative predictive value and could have an important role in ruling out the need for cranial computed tomography scan after minor head injury. This appears to be of substantial clinical relevance, particularly in countries where trauma incidence is high and medical resources are limited, such as in Brazil.INTRODUÇÃO: A liberação da proteína neuronal S-100B na circulação tem sido sugerida como indicadora de dano neuronal. Foi testada a hipótese de que a S-100B é um marcador útil e custo efetivo para a triagem de pacientes com trauma craniano leve. MÉTODO: Cinqüenta pacientes consecutivos com trauma craniano isolado foram prospectivamente avaliados na sala de emergência de um Centro de Trauma brasileiro pela tomografia computadorizada de crânio e por amostras de sangue venoso, para a medida no soro da proteína S-100B utilizando um teste recentemente desenvolvido; 21 pessoas normais foram utilizadas como controles negativos. Os resultados são apresentados como mediana e percentis 25-75. RESULTADOS: Os pacientes chegaram ao Centro de Trauma em média 45 min (30-62) após o trauma craniano leve. Seis dos 50 pacientes tiveram lesões pós-traumáticas relevantes segundo a tomografia computadorizada de crânio inicial (12%) e foram considerados como positivos. A concentração mediana de S-100B nestes pacientes foi de 0,75µg/L (0,66-6,5), significativamente maior (U-teste,

    Spectroscopy of 28^{28}Na: shell evolution toward the drip line

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    Excited states in 28^{28}Na have been studied using the β\beta-decay of implanted 28^{28}Ne ions at GANIL/LISE as well as the in-beam γ\gamma-ray spectroscopy at the NSCL/S800 facility. New states of positive (Jπ^{\pi}=3,4+^+) and negative (Jπ^{\pi}=1-5^-) parity are proposed. The former arise from the coupling between 0d_5/2\_{5/2} protons and a 0d_3/2\_{3/2} neutron, while the latter are due to couplings with 1p_3/2\_{3/2} or 0f_7/2\_{7/2} neutrons. While the relative energies between the Jπ^{\pi}=1-4+^+ states are well reproduced with the USDA interaction in the N=17 isotones, a progressive shift in the ground state binding energy (by about 500 keV) is observed between 26^{26}F and 30^{30}Al. This points to a possible change in the proton-neutron 0d_5/2\_{5/2}-0d_3/2\_{3/2} effective interaction when moving from stability to the drip line. The presence of Jπ^{\pi}=1-4^- negative parity states around 1.5 MeV as well as of a candidate for a Jπ^{\pi}=5^- state around 2.5 MeV give further support to the collapse of the N=20 gap and to the inversion between the 0f_7/2\_{7/2} and 1p_3/2\_{3/2} levels below Z=12. These features are discussed in the framework of Shell Model and EDF calculations, leading to predicted negative parity states in the low energy spectra of the 26^{26}F and 25^{25}O nuclei.Comment: Exp\'erience GANIL/LISE et NSCL/S80

    Improvement of pyclen-based manganese complexes relaxivity by using polymersome vesicles

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    NANOPARTICULES D'OXYDE DE FER OU DE MANGANÈSE DENDRONISÉES POUR L'IRM - Fédération Wallonie Bruxelle
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