4,759 research outputs found

    Research and calibration of Acoustic Sensors in ice within the SPATS (South Pole Acoustic Test Setup) project

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    We present development work aiming towards a large scale ice-based hybrid detector including acoustic sensors for the detection of neutrinos in the GZK range. A facility for characterization and calibration of acoustic sensors in clear (bubble-free) ice has been developed and the first measurements done at this facility are presented. Further, a resonant sensor intended primarily for characterization of the ambient noise in the ice at the South Pole has been developed and some data from its performance are given.Comment: 4 pages, 8 figures, ARENA 2010 conference proceeding

    Adaptive Surrogate-Based Optimization of Vortex Generators for a Tiltrotor Geometry

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    Design of vortex generators (VGs) on a tiltrotor aircraft infinite wing is presented using an adaptive surrogate modelling approach. Particular design issues in tiltrotors produce wings that are thick and highly loaded, so separation and early onset buffet can be problematic and VGs are commonly used to alleviate these issues. In this work, the design of VGs for elimination of separation is considered using a viscous flowfield simulations. A large design space of rectangular vane-type vortex generators is sampled and simulated, and a radial basis function surrogate model is implemented to model the full design space. An efficient adaptive sampling approach for improved design space sampling has also been developed that balances the properties of space-filling, curvature capture and optimum locating. This approach has been tested on the design of a VG on a highly loaded infinite wing, with a representative tiltrotor airfoil section, using a five-dimensional design space. Design of the VGs using this approach shows that elimination of the separation is possible whilst simultaneously reducing the drag of the wing with optimized the VGs, compared to the clean wing

    Uncertainty quantification of coal seam gas production prediction using Polynomial Chaos

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    A surrogate model approximates a computationally expensive solver. Polynomial Chaos is a method to construct surrogate models by summing combinations of carefully chosen polynomials. The polynomials are chosen to respect the probability distributions of the uncertain input variables (parameters); this allows for both uncertainty quantification and global sensitivity analysis. In this paper we apply these techniques to a commercial solver for the estimation of peak gas rate and cumulative gas extraction from a coal seam gas well. The polynomial expansion is shown to honour the underlying geophysics with low error when compared to a much more complex and computationally slower commercial solver. We make use of advanced numerical integration techniques to achieve this accuracy using relatively small amounts of training data

    Novel perspectives for the application of total internal reflection microscopy

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    Total Internal Reflection Microscopy (TIRM) is a sensitive non-invasive technique to measure the interaction potentials between a colloidal particle and a wall with femtonewton resolution. The equilibrium distribution of the particle-wall separation distance z is sampled monitoring the intensity I scattered by the Brownian particle under evanescent illumination. Central to the data analysis is the knowledge of the relation between I and the corresponding z, which typically must be known a priori. This poses considerable constraints to the experimental conditions where TIRM can be applied (short penetration depth of the evanescent wave, transparent surfaces). Here, we introduce a method to experimentally determine I(z) by relying only on the distance-dependent particle-wall hydrodynamic interactions. We demonstrate that this method largely extends the range of conditions accessible with TIRM, and even allows measurements on highly reflecting gold surfaces where multiple reflections lead to a complex I(z).Comment: 11 pages, 7 figure

    Plaque size is decreased but M1 macrophage polarization and rupture related metalloproteinase expression are maintained after deleting T-bet in ApoE null mice

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    BACKGROUND:Thelper1 (Th1) lymphocytes have been previously implicated in atherosclerotic plaque growth but their role in plaque vulnerability to rupture is less clear. We investigated whether T-bet knockout that prevents Th1 lymphocyte differentiation modulates classical (M1) macrophage activation or production of matrix degrading metalloproteinases (MMPs) and their tissue inhibitors, TIMPs. METHODS & RESULTS:We studied the effect of T-bet deletion in apolipoproteinE (ApoE) knockout mice fed a high fat diet (HFD) or normal chow diet (ND). Transcript levels of M1/M2 macrophage polarization markers, selected MMPs and TIMPs were measured by RT-qPCR in macrophages isolated from subcutaneous granulomas or in whole aortae. Immunohistochemistry of aortic sinus (AS) and brachiocephalic artery (BCA) plaques was conducted to quantify protein expression of the same factors. Deletion of T-bet decreased mRNA for the M1 marker NOS-2 in granuloma macrophages but levels of M2 markers (CD206, arginase-1 and Ym-1), MMPs-2, -9, -12, -13, -14 and -19 or TIMPs-1 to -3 were unchanged. No mRNA differences were observed in aortic extracts from mice fed a HFD for 12 weeks. Moreover, AS and BCA plaques were similarly sized between genotypes, and had similar areas stained for NOS-2, COX-2, MMP-12 and MMP-14 proteins. T-bet deletion increased MMP-13, MMP-14 and arginase-1 in AS plaques. After 35 weeks of ND, T-bet deletion reduced the size of AS and BCA plaques but there were no differences in the percentage areas stained for M1 or M2 markers, MMPs-12, -13, -14, or TIMP-3. CONCLUSIONS:Absence of Th1 lymphocytes is associated with reduced plaque size in ApoE knockout mice fed a normal but not high fat diet. In either case, M1 macrophage polarization and expression of several MMPs related to plaque instability are either maintained or increased

    Prenatal diagnosis of proximal focal femoral deficiency: Literature review of prenatal sonographic findings

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    Proximal focal femoral deficiency (PFFD) is a rare musculoskeletal malformation that occurs in 0.11-0.2 per 10,000 live births. This congenital anomaly involves the pelvis and proximal femur with widely variable manifestations, from mild femoral shortening and hypoplasia to the absence of any functional femur and acetabular aplasia. Prenatal diagnosis of PFFD is still a challenge, but early recognition of this malformation could provide useful information to both parents and physicians concerning management and therapeutic planning. For this review, we analyzed all the cases of prenatally diagnosed PFFD that were reported in the literature from 1990 to 2014 and provide a description of the most common prenatal sonographic findings

    Minimal breast milk transfer of rituximab, a monoclonal antibody used in neurological conditions.

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    ObjectiveTo determine the transfer of rituximab, an anti-CD20 monoclonal antibody widely used for neurologic conditions, into mature breast milk.MethodsBreast milk samples were collected from 9 women with MS who received rituximab 500 or 1,000 mg intravenous once or twice while breastfeeding from November 2017 to April 2019. Serial breast milk samples were collected before infusion and at 8 hours, 24 hours, 7 days, and 18-21 days after rituximab infusion in 4 patients. Five additional patients provided 1-2 samples at various times after rituximab infusion.ResultsThe median average rituximab concentration in mature breast milk was low at 0.063 μg/mL (range 0.046-0.097) in the 4 patients with serial breast milk collection, with an estimated median absolute infant dose of 0.0094 mg/kg/d and a relative infant dose (RID) of 0.08% (range 0.06%-0.10%). Most patients had a maximum concentration at 1-7 days after infusion. The maximum concentration occurred in a woman with a single breast milk sample and was 0.29 μg/mL at 11 days postinfusion, which corresponds with an estimated RID of 0.33%. Rituximab concentration in milk was virtually undetectable by 90 days postinfusion.ConclusionsWe determined minimal transfer of rituximab into mature breast milk. The RID for rituximab was less than 0.4% and well below theoretically acceptable levels of less than 10%. Low oral bioavailability would probably also limit the absorption of rituximab by the newborn. In women with serious autoimmune neurologic conditions, monoclonal antibody therapy may afford an acceptable benefit to risk ratio, supporting both maternal treatment and breastfeeding

    Derivation of a clinical decision guide in the diagnosis of cervical facet joint pain

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    Objective To derive a clinical decision guide (CDG) to identify patients best suited for cervical diagnostic facet joint blocks. Design Prospective cohort study. Setting Pain management center. Participants Consecutive patients with neck pain (N=125) referred to an interventional pain management center were approached to participate. Interventions Subjects underwent a standardized testing protocol, performed by a physiotherapist, prior to receiving diagnostic facet joint blocks. All subjects received the reference standard diagnostic facet joint block protocol, namely controlled medial branch blocks (MBBs). The physicians performing the MBBs were blinded to the local anesthetic used and findings of the clinical tests. Main Outcome Measures Multivariate regression analyses were performed in the derivation of the CDGs. Sensitivity, specificity, positive and negative likelihood ratios, and 95% confidence intervals (CIs) were calculated for the index tests and CDGs. Results A CDG involving the findings of the manual spinal examination (MSE), palpation for segmental tenderness (PST), and extension-rotation (ER) test demonstrated a specificity of 84% (95% CI, 77-90) and a positive likelihood ratio of 4.94 (95% CI, 2.8-8.2). Sensitivity of the PST and MSE were 94% (95% CI, 90-98) and 92% (95% CI, 88-97), respectively. Negative findings on the PST were associated with a negative likelihood ratio of.08 (95% CI,.03-.24). Conclusions MSE, PST, and ER may be useful tests in identifying patients suitable for diagnostic facet joint blocks. Further research is needed to validate the CDGs prior to their routine use in clinical practice
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