900 research outputs found

    Design of large power surface-mounted permanent-magnet motors using post-assembly magnetization

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    This paper reports the design process for the manufacture of higher power rare-earth permanent-magnet motors using post-assembly magnetization. With these machines, difficulties can be encountered in production using normal manufacturing processes due to the high intensity of rare-earth magnets that are pre-magnetized. Post-assembly magnetization utilizes the stator windings of a permanent-magnet motor to magnetize the magnets after complete assembly (so that the problem can be solved). However, with post-assembly magnetization, some parameters such as slot-fill factor, number of turns, wire diameter, etc., must be considered for the magnetization, as well as the motor operation. The machine design should be able to meet the required specification as a motor and ensure correct magnetization is possible. In this paper, a design process is described that incorporates the design considerations for post-assembly magnetization (for the requirements for complete magnetization) together with the design requirements for successful motor operation. A 6kW surface-mounted permanent-magnet motor is designed using the proposed process, and finite element analysis verifies the feasibility of the presented method. ©2007 IEEE

    Local P T symmetry violates the no-signaling principle

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    Bender et al. [Phys. Rev. Lett. 80, 5243 (1998)] have developed PT-symmetric quantum theory as an extension of quantum theory to non-Hermitian Hamiltonians. We show that when this model has a local PT symmetry acting on composite systems, it violates the nonsignaling principle of relativity. Since the case of global PT symmetry is known to reduce to standard quantum mechanics A. Mostafazadeh [J. Math. Phys. 43, 205 (2001)], this shows that the PT-symmetric theory is either a trivial extension or likely false as a fundamental theory. © 2014 American Physical Society

    Passive PT -symmetric couplers without complex optical potentials

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    © 2015 American Physical Society. In addition to the implementation of parity-time-(PT-) symmetric optical systems by carefully and actively controlling the gain and loss, we show that a 2×2 PT-symmetric Hamiltonian has a unitarily equivalent representation without complex optical potentials in the resulting optical coupler. Through the Naimark dilation in operator algebra, passive PT-symmetric couplers can thus be implemented with a refractive index of real values and asymmetric coupling coefficients. This opens up the possibility to implement general PT-symmetric systems with state-of-the-art asymmetric slab waveguides, dissimilar optical fibers, or cavities with chiral mirrors

    A urinary Common Rejection Module (uCRM) score for non-invasive kidney transplant monitoring.

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    A Common Rejection Module (CRM) consisting of 11 genes expressed in allograft biopsies was previously reported to serve as a biomarker for acute rejection (AR), correlate with the extent of graft injury, and predict future allograft damage. We investigated the use of this gene panel on the urine cell pellet of kidney transplant patients. Urinary cell sediments collected from patients with biopsy-confirmed acute rejection, borderline AR (bAR), BK virus nephropathy (BKVN), and stable kidney grafts with normal protocol biopsies (STA) were analyzed for expression of these 11 genes using quantitative polymerase chain reaction (qPCR). We assessed these 11 CRM genes for their abundance, autocorrelation, and individual expression levels. Expression of 10/11 genes were elevated in AR when compared to STA. Psmb9 and Cxcl10could classify AR versus STA as accurately as the 11-gene model (sensitivity = 93.6%, specificity = 97.6%). A uCRM score, based on the geometric mean of the expression levels, could distinguish AR from STA with high accuracy (AUC = 0.9886) and correlated specifically with histologic measures of tubulitis and interstitial inflammation rather than tubular atrophy, glomerulosclerosis, intimal proliferation, tubular vacuolization or acute glomerulitis. This urine gene expression-based score may enable the non-invasive and quantitative monitoring of AR

    Constructing an index for brand equity : a hospital example

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    Author name used in this publication: Po-An J.J. Hsieh2010-2011 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

    Gender Dimorphism of the Cardiac Dysfunction in Murine Sepsis: Signalling Mechanisms and Age-Dependency

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    This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.JC is supported by a jointly funded PhD-studentship of the China Scholarship Council (grant number 201206240146) and Queen Mary University of London (QMUL). SMC is supported by a Research Fellowship of the German Research Foundation (Deutsche Forschungsgemeinschaft; DFG CO 912/1-1). NSAP is, in part, supported by the Bart’s and The London Charity (753/1722). This work is supported, in part, by the William Harvey Research Foundation and by a grant from the University of Turin (Ricerca Locale ex-60% 2013). This work forms part of the research themes contributing to the translational research portfolio of Barts and the London Cardiovascular Biomedical Research Unit, which is supported and funded by the National Institute of Health Research. This work also contributes to the Organ Protection research theme of the Barts Centre for Trauma Sciences, supported by the Barts and The London Charity (Award 753/1722)

    Comparison of coplanar and noncoplanar intensity-modulated radiation therapy and helical tomotherapy for hepatocellular carcinoma

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    <p>Abstract</p> <p>Background</p> <p>To compare the differences in dose-volume data among coplanar intensity modulated radiotherapy (IMRT), noncoplanar IMRT, and helical tomotherapy (HT) among patients with hepatocellular carcinoma (HCC) and portal vein thrombosis (PVT).</p> <p>Methods</p> <p>Nine patients with unresectable HCC and PVT underwent step and shoot coplanar IMRT with intent to deliver 46 - 54 Gy to the tumor and portal vein. The volume of liver received 30Gy was set to keep less than 30% of whole normal liver (V30 < 30%). The mean dose to at least one side of kidney was kept below 23 Gy, and 50 Gy as for stomach. The maximum dose was kept below 47 Gy for spinal cord. Several parameters including mean hepatic dose, percent volume of normal liver with radiation dose at X Gy (Vx), uniformity index, conformal index, and doses to organs at risk were evaluated from the dose-volume histogram.</p> <p>Results</p> <p>HT provided better uniformity for the planning-target volume dose coverage than both IMRT techniques. The noncoplanar IMRT technique reduces the V10 to normal liver with a statistically significant level as compared to HT. The constraints for the liver in the V30 for coplanar IMRT vs. noncoplanar IMRT vs. HT could be reconsidered as 21% vs. 17% vs. 17%, respectively. When delivering 50 Gy and 60-66 Gy to the tumor bed, the constraints of mean dose to the normal liver could be less than 20 Gy and 25 Gy, respectively.</p> <p>Conclusion</p> <p>Noncoplanar IMRT and HT are potential techniques of radiation therapy for HCC patients with PVT. Constraints for the liver in IMRT and HT could be stricter than for 3DCRT.</p

    The impact of sodium-glucose co-transporter-2 inhibitors on dementia and cardiovascular events in diabetic patients with atrial fibrillation

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    Aims: The effectiveness of sodium-glucose co-transporter-2 inhibitors (SGLT2i) on incident dementia in patients with diabetes and atrial fibrillation (AF) remains unknown. This study aimed to investigate the association between SGLT2i and the risk of incident dementia in diabetic patients with AF, and to explore the interactions with oral anticoagulants or dipeptidyl peptidase-4 inhibitors (DPP4i). Materials and Methods: We conducted a cohort study using Taiwan's National Health Insurance Research Database. Patients with diabetes and AFwithout a prior history of established cardiovascular diseases, were identified. Using propensity score matching, 810 patients receiving SGLT2i were matched with 1620 patients not receiving SGLT2i. The primary outcome was incident dementia, and secondary outcomes included composite cardiovascular events and mortality. Results: After up to 5 years of follow-up, SGLT2i use was associated with a significantly lower risk of incident dementia (hazard: 0.71, 95% confidence interval: 0.51–0.98), particularly vascular dementia (HR: 0.44, 95% CI: 0.24–0.82). SGLT2i was related to reduced risks of AF-related hospitalisation (HR: 0.72, 95% CI: 0.56–0.93), stroke (HR: 0.75, 95% CI: 0.60–0.94), and all-cause death (HR: 0.33, 95% CI: 0.24–0.44). The protective effects were consistent irrespective of the concurrent use of non-vitamin K antagonist oral anticoagulants (NOACs) or DPP4i. Conclusions: In diabetic patients with AF, SGLT2i was associated with reduced risks of incident dementia, AF-related hospitalisation, stroke, and all-cause death. The protective effects were independent of either concurrent use of NOACs or DPP4i
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