1,081 research outputs found

    A model-based approach to stabilizing crutch supported paraplegic standing by artifical hip joint stiffness

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    The prerequisites for stable crutch supported standing were analyzed in this paper. For this purpose, a biomechanical model of crutch supported paraplegic stance was developed assuming the patient was standing with extended knees. When using crutches during stance, the crutches will put a position constraint on the shoulder, thus reducing the number of degrees of freedom. Additional hip-joint stiffness was applied to stabilize the hip joint and, therefore, to stabilize stance. The required hip-joint stiffness for changing crutch placement and hip-joint offset angle was studied under static and dynamic conditions. Modeling results indicate that, by using additional hip-joint stiffness, stable crutch supported paraplegic standing can be achieved, both under static as well as dynamic situations. The static equilibrium postures and the stability under perturbations were calculated to be dependent on crutch placement and stiffness applied. However, postures in which the hip joint was in extension (C postures) appeared to the most stable postures. Applying at least 60 N /spl middot/ m/rad hip-joint stiffness gave stable equilibrium postures in all cases. Choosing appropriate hip-joint offset angles, the static equilibrium postures changed to more erect postures, without causing instability or excessive arm forces to occur

    Phase modulation parallel optical delay detector for microwave angle-of-arrival measurement with accuracy monitored

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    A novel phase modulation parallel optical delay detector is proposed for microwave angle-of-arrival (AOA) measurement with accuracy monitored by using only one dual-electrode Mach-Zenhder modulator. A theoretical model is built up to analyze the proposed system including measurement accuracy monitoring. The spatial delay measurement is translated into the phase shift between two replicas of a microwave signal. Thanks to the accuracy monitoring, the phase shifts from 5{\deg} to 165{\deg} are measured with less than 3.1{\deg} measurement error

    No Difference in Recovery of Patient-Reported Outcome and Range of Motion between Cruciate Retaining and Posterior Stabilized Total Knee Arthroplasty:A Double-Blind Randomized Controlled Trial

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    Both from the perspective of the individual and from a socioeconomic point of view (e.g., return to work), it is important to have an insight into the potential differences in recovery between posterior cruciate ligament retaining (PCR) and posterior stabilized (PS) total knee arthroplasty (TKA) implants. The primary aim of this study was to compare the speed of recovery of patient-reported outcome between patients with a PCR and PS TKA during the first postoperative year. The secondary aim was to compare the effect on range of motion (ROM). In a randomized, double-blind, controlled, single-center trial, 120 adults diagnosed with osteoarthritis of the knee were randomized into either the PCR or PS group. Primary outcome was speed of recovery of patient-reported pain and function, measured with the Western Ontario and McMaster Universities osteoarthritis index (WOMAC), with a follow-up of 1year. Main secondary outcome measure was ROM. A generalized estimating equations (GEE) analysis was used to assess whether there was a difference over time between groups (" p -value for interaction"). Between 2008 and 2011, 59 participants received a PCR TKA (mean age, 70.3 years [SD=7.7]; mean body mass index [BMI], 30.5kg/m (2) [SD=5.4]) and 55 participants a PS TKA (mean age, 73.5 years [SD=7.0]; mean BMI, 29.2kg/m (2) [SD=4.4]). Six patients (two PCR and four PS) were excluded because of early drop-out, so 114 patients (95%) were available for analysis. In between group difference for total WOMAC score was -1.3 (95% confidence interval [CI]: -5.6 to 3.1); p -value for interaction was 0.698. For ROM, in between group difference was 1.1 (95% CI: -2.6 to 4.7); p -value for interaction was 0.379. These results demonstrated that there are no differences in speed of recovery of WOMAC or ROM during the first postoperative year after PCR or PS TKA

    Cell type-specific acquired protection from crystal adherence by renal tubule cells in culture

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    Cell type-specific acquired protection from crystal adherence by renal tubule cells in culture.BackgroundAdherence of crystals to the surface of renal tubule epithelial cells is considered an important step in the development of nephrolithiasis. Previously, we demonstrated that functional monolayers formed by the renal tubule cell line, Madin-Darby canine kidney (MDCK), acquire protection against the adherence of calcium oxalate monohydrate crystals. We now examined whether this property is cell type specific. The susceptibility of the cells to crystal binding was further studied under different culture conditions.MethodsCell-type specificity and the influence of the growth substrate was tested by comparing calcium oxalate monohydrate crystal binding to LLC-PK1 cells and to two MDCK strains cultured on either permeable or impermeable supports. These cell lines are representative for the renal proximal tubule (LLC-PK1) and distal tubule/collecting duct (MDCK) segments of the nephron, in which crystals are expected to be absent and present, respectively.ResultsWhereas relatively large amounts of crystals adhered to subconfluent MDCK cultures, the level of crystal binding to confluent monolayers was reduced for both MDCK strains. On permeable supports, MDCK cells not only obtained a higher level of morphological differentiation, but also acquired a higher degree of protection than on impermeable surfaces. Crystals avidly adhered to LLC-PK1 cells, irrespective of their developmental stage or growth substrate used.ConclusionsThese results show that the prevention of crystal binding is cell type specific and expressed only by differentiated MDCK cells. The anti-adherence properties acquired by MDCK cells may mirror a specific functional characteristic of its in situ equivalent, the renal distal tubule/collecting ducts

    The Value of Pre-Ablative I-131 Scan for Clinical Management in Patients With Differentiated Thyroid Carcinoma

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    BACKGROUND: A diagnostic I-131 (Dx) scan is used to detect a thyroid remnant or metastases before treatment of differentiated thyroid cancer (DTC) with I-131. The aim of this study is to specify in which patients with DTC a Dx scan could have an additional value, by studying the effect of the Dx scan on clinical management. METHODS: Patients with DTC, treated with I-131 after thyroidectomy were included in this retrospective cohort study. Twenty-four hours after administration of 37 MBq I-131 a whole body Dx scan and an uptake measurement at the original thyroid bed were performed. Outcomes of the Dx scan and the subsequent changes in clinical management, defined as additional surgery or adjustment of I-131 activity, were reported. Risk factors for a change in clinical management were identified with a binary logistic regression. RESULTS: In 11 (4.2%) patients clinical management was changed, including additional surgery (n=5), lowering I-131 activity (n=5) or both (n=1). Risk factors for a change in clinical management were previous neck surgery (OR 5.9, 95% CI: 1.4-24.5), surgery in a non-tertiary center (OR 13.4, 95% CI: 2.8 – 63.8), TSH <53.4 mU/L (OR 19.64, 95% CI: 4.94-78.13), thyroglobulin ≥50.0 ng/L (OR 7.4, 95% CI: 1.6-34.9) and free T4 ≥4.75 pmol/L (OR 156.8, 95% CI: 128.4-864.2) CONCLUSION: The Dx scan can potentially change clinical management before treatment with I-131, but the yield is low. A Dx-scan should only be considered for patients with a high pre-scan risk of a change in management, based on patient history and prior center-based surgical outcomes