1,031 research outputs found

    Pilot study : a comparison between a hands-on and a hands-off socket design, using fixed socket fit criteria and dynamic stump/socket interface pressure measurements

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    The research of existing and the development of new trans-tibial socket concepts are on the agenda of most researchers and clinicians in this field. However, the understanding of the mechanisms contributing to a 'good fit' concept is hampered by the complexity of soft tissue behaviour as the load transferring medium within the socket. There is also a lack of consensus on the description of a good fit. There is no doubt that advances in relation to fitting techniques have been made, but to what extent those advances contribute to enhanced quality of fit is uncertain

    The rising role of photonics in today's data centres

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    In recent years there has been a rapid growth in demand for ultra high speed data transmission with end users expecting fast, high bandwidth network access. This growth has put data centres under increasing pressure to provide greater data throughput and ever increasing data rates while at the same time improving the quality of data handling in terms of reduced latency, increased scalability and improved channel speed for users. However, data networks are becoming increasingly difficult to scale to meet this growing demand using current well established CMOS technology and architectures. As a result electronic bottlenecks are becoming apparent despite improvements in data management. The inter-related issues of electronic scalability, power consumption, copper interconnect bandwidth and the limited speed of CMOS electronics will be discussed; and the tremendous potential of optical fibre based networks to provide the necessary bandwidth will be illustrated. In addition, some applications of photonics to alleviate speed, throughput and latency issues in data networks will be discussed. Finally, progress in the form of a novel and highly scalable optical interconnect will be reviewed

    Fibre laser hydrophones for cosmic ray particle detection

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    The detection of ultra high energetic cosmic neutrinos provides a unique means to search for extragalactic sources that accelerate particles to extreme energies. It allows to study the neutrino component of the GZK cut-off in the cosmic ray energy spectrum and the search for neutrinos beyond this limit. Due to low expected flux and small interaction cross-section of neutrinos with matter large experimental set-ups are needed to conduct this type of research. Acoustic detection of cosmic rays may provide a means for the detection of ultra-high energetic neutrinos. Using relative low absorption of sound in water, large experimental set-ups in the deep sea are possible that are able to detect these most rare events, but it requires highly sensitive hydrophones as the thermo-acoustic pulse originating from a particle shower in water has a typical amplitude as low as a mPa. It has been shown in characterisation measurements that the fibre optic hydrophone technology as designed and realised at TNO provides the required sensitivity. Noise measurements and pulse reconstruction have been conducted that show that the hydrophone is suited as a particle detector.Comment: Submitted to the proceedings of "13th Topical Seminar on Innovative Particle and Radiation Detectors (IPRD13)

    Banquetes togados: el imaginario romano del "symposion" en los fragmentos cómicos de Titinio, Afranio y Atta

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    Recientemente, Dupont (2005a) ha demostrado de qué modo la comedia palliata introduce en escena una "otredad" que, lejos de provenir de sus orígenes extranjeros, el propio texto crea desde su lógica compositiva. Su noción de "alterité incluse", desde esta perspectiva, es útil para explicar en el género cómico toda una serie de alusiones al mundo griego originadas en la propia cosmovisión de los romanos, y esto se advierte especialmente en lo que se refiere al universo de los placeres. Ante esta reflexión, nos propusimos pensar si es posible validar este marco teórico a partir de los testimonios de aquella vertiente cómica republicana que, frente a la tradición helenística, se caracteriza por su argumento local: nos referimos a la comoedia togata. En este artículo nos proponemos examinar en qué términos se produce la construcción textual del banquete en el seno de la fa bula togata

    The use of physical activity outcomes in rehabilitation interventions for lower limb amputees : a systematic review

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    BACKGROUND: Interventions which have focused on improving the physical activity of individuals with lower limb amputation can be mostly categorized into behavioural-based and prosthetic-based interventions. The aim of this review was to assess the quality of these interventions, and to identify the key gaps in research in this field. METHODOLOGY: The databases of Scopus, Pubmed, Embase, Medline and Web of Science were searched between September and December of 2019 for articles relating to physical activity, amputees and interventions. Articles were assessed quantitively based on internal validity, external validity and intervention intensity. FINDINGS: Sixteen articles (5 behavioural, 11 prosthetic) were assessed. Both approaches had comparable methodological quality and mixed efficacy for producing a significant change in physical activity outcomes. Almost all interventions used a simplistic measurement of activity as their outcome. CONCLUSIONS: There is an insufficient amount of studies to assess the overall efficacy of behavioural interventions in regard to how they impact on physical activity behaviour. However, the increase of quality of the methodology in the more recent studies could indicate that future interventions will retain similar levels of quality. Prosthetic interventions have shown no major improvement in efficacy compared to similar reviews and may need to utilise more advanced prosthetic components to attain significant changes in physical activity. Activity outcomes should expand into more complex activity measurements to properly understand the physical activity profile of people with lower limb amputation

    Investigation of wrist and hand function for the improvement of upper limb prosthetic device design

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    The development of upper limb prostheses faces many different challenges. Speciically, improvements in device design are urgently required, together with increased personalisation of devices according to patients’ needs and overall device ease of use and affordability. This investigation is part of a project entitled Anthropomorphic Design for Advanced Manufacturing (ADAM) which aims to develop a new Design System for personalisation of upper limb prosthetics using additive manufacturing technology. Here, a novel procedure for acquiring data on the movement features of the sound and prosthetic upper limb will be presented, as input for those design requirements

    Value of histopathologic analysis of subcutis excisions by general practitioners

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    BACKGROUND: Only around 60% of skin lesions excised by GPs are referred to a pathologist. Clinical diagnoses of skin excisions by GPs may not be very accurate. Subcutis excisions are rarely done by GPs, and there is hence little information in the literature on the histopathological yield of subcutis excisions by GPs with regard to malignancies. The aim of this study was to evaluate the yield of histopathological investigation of a relatively large group of subcutis excisions by GPs, with special emphasis on discrepancies between clinical and histopathological diagnoses of malignancy. METHODS: We investigated a series of 90 subcutis excisions, which was derived from a database of consecutive GP submissions from the years 1999–2000 where in the same time period 4595 skin excisions were performed by the same group of GPs. This underlines the apparent reluctance of GPs to perform subcutis excisions. RESULTS: The final diagnosis was benign in 88 cases (97.8%) and malignant in 2 cases (2.2%). Seven cases had no clinical diagnosis, all of which were benign. Of the 83 clinically benign cases, 81 (97.6%) were indeed benign and 2 (2.4%) were malignant: one Merkel cell carcinoma and one dermatofibrosarcoma protuberans. The former was clinically thought to be a lipoma, and the latter a trichilemmal cyst. The dermatofibrosarcoma protuberans presented at the age of 27, and the Merkel cell carcinoma at the age of 60. Both were incompletely removed and required re-excision by a surgical oncologist. CONCLUSION: Histopathological investigation of subcutis excisions by GPs yields unexpected and rare malignancies in about 2% of cases that may initially be excised inadequately. Based on these data, and because of the relatively rareness of these type of excisions, it could be argued that it may be worthwhile to have all subcutis excisions by GPs routinely investigated by histopathology

    Development of an ex vivo model to study the response of skeletal muscle to transverse mechanical loading

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    Development of an ex vivo model to study the response of skeletal muscle to transverse mechanical loading. M. Graser, A. Wark, S. Day, A. Buis, The soft tissues in our body, particularly skeletal muscles, commonly experience physical stress. In most cases, the muscles can maintain the balance between damage and regeneration. However, this balance might be disturbed in certain populations that are subject to extreme cases  of overload or repeated impact, like individuals spinal cord injury [3] or transtibial prosthetic users [2].To characterise critical loading scenarios, experimental models of skeletal muscle under mechanical loading are necessary [4, 5]. A controllable environment as well as the reproduction of the highly hierarchical structure of skeletal muscle are thereby desirable. We therefore developed an ex vivo model to study the response of skeletal muscle to transverse mechanical loading. MethodsSoleus and extensor digitorum longus muscles of male Sprague Dawley rats were dissected and transversely compressed (2mm indenter, 9-32kPa) (Fig. 1). Control tissues were held under the same conditions for the same time without loading. Subsequently, tissue viability and morphology were assessed through standard histological procedures using Procion Yellow MX4R and Live-or-Dye™ for fluorescent dead cell staining as well as H&E. Additionally, biochemical changes of cell and tissue damaged were visualised with multiphoton Raman microscopy of unstained samples.Figure 1: Schematic of ex vivo model. A: Skeletal muscle dissection; B: Mechanical loading; C: Image analysis for cell damage; D: Data analysis to establish the relationship between loading conditions and cell damage.Results & DiscussionWhilst control samples showed only minor loss in cell viability throughout the experimental time frame (max. 3h), mechanical damage in loaded tissues was readily distinguishable. Imaging revealed a partial loss of cross-striations, disorganised and disrupted muscle fibres, increased interstitial space, and loss of cell viability. With careful control of the experimental setup, detailed imaging of local cellular damage in response to loading conditions could be obtained. ConclusionOur ex vivo model of skeletal muscle for transverse mechanical loading is suitable for quantifying cellular damage. Looking at this microscale will provide important insights into the adaptive capabilities of skeletal muscle. This can provide the basis for further research into the role of soft tissue deformation in limb pain and ulcer formation and could inform future directions for socket design and fit

    Enhancement of drug oxidation and conjugation by carcinogens in different rat tissues

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    OBJECTIVE After endoscopic third ventriculostomy (ETV), some patients develop recurrent symptoms of hydrocephalus. The optimal treatment for these patients is not clear: repeat ETV (re-ETV) or CSF shunting. The goals of the study were to assess the effectiveness of re-ETV relative to initial ETV in pediatric patients and validate the ETV success score (ETVSS) for re-ETV. METHODS Retrospective data of 624 ETV and 93 re-ETV procedures were collected from 6 neurosurgical centers in the Netherlands (1998-2015). Multivariable Cox proportional hazards modeling was used to provide an adjusted estimate of the hazard ratio for re-ETV failure relative to ETV failure. The correlation coefficient between ETVSS and the chance of re-ETV success was calculated using Kendall's tau coefficient. Model discrimination was quantified using the c-statistic. The effects of intraoperative findings and management on re-ETV success were also analyzed. RESULTS The hazard ratio for re-ETV failure relative to ETV failure was 1.23 (95% CI 0.90-1.69; p = 0.20). At 6 months, the success rates for both ETV and re-ETV were 68%. ETVSS was significantly related to the chances of re-ETV success (tau = 0.37; 95% bias corrected and accelerated CI 0.21-0.52; p < 0.001). The c-statistic was 0.74 (95% CI 0.64-0.85). The presence of prepontine arachnoid membranes and use of an external ventricular drain (EVD) were negatively associated with treatment success, with ORs of 4.0 (95% CI 1.5-10.5) and 9.7 (95% CI 3.4-27.8), respectively. CONCLUSIONS Re-ETV seems to be as safe and effective as initial ETV. ETVSS adequately predicts the chance of successful re-ETV. The presence of prepontine arachnoid membranes and the use of EVD negatively influence the chance of success
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