Comparative investigation of stator-mounted permanent magnet machines under fault conditions

Here, machines having permanent magnets (PM) mounted in the stator are compared during fault operations such as armature winding short circuits. The magnet potential irreversible demagnetisation is also investigated due to the fact that the PMs are placed close to the armature coils (heat sources) and hence are prone to temperature-related demagnetisations. It is found that the doubly salient and flux reversal machines have inherently higher fault tolerant capabilities when compared with the switched-flux one. To the point of view of demagnetisation withstand capability, the doubly salient topology stands out as the most robust one while the switched flux is the weakest one

Osteoporosis in the community. Sensitivity of self-reported estimates and medication use of those diagnosed with the condition

Objectives: To assess the sensitivity and specificity of self-reported osteoporosis compared with dual energy X-ray absorptiometry (DXA) defined osteoporosis, and to describe medication use among participants with the condition. Methods: Data were obtained from a population-based longitudinal study and assessed for the prevalence of osteoporosis, falls, fractures and medication use. DXA scans were also undertaken. Results: Overall 3.8% (95% confidence interval (CI) 3.2 to 4.5) of respondents and 8.8% (95% CI 7.5 to 10.3) of those aged ≥ 50 years reported that they had been diagnosed with osteoporosis by a doctor. The sensitivity (those self-reporting osteoporosis and having low bone mineral density (BMD) on DXA) was low (22.7%), although the specificity was high (94.4%). Only 16.1% of those aged ≥ 50 years and with DXA-defined osteoporosis were taking bisphosphonates. Conclusions: The sensitivity of self-reporting to identify osteoporosis is low. Anti-osteoporotic medications are an important part of osteoporosis treatment but opportunities to use appropriate medications were missed and inappropriate medications were used.T. K. Gill, A. W. Taylor, C. L. Hill, P. J. Phillip

Naložba za prihodnost

BACKGROUND: The supplementation with vitamin D and calcium has been recommended for elderly, specifically those with increased risk of fractures older than 65 years. This study aims to assess the cost-effectiveness of vitamin D and calcium supplementation in elderly women and men with osteoporosis and therefore to assess if this recommendation is justified in terms of cost-effectiveness. METHODS: A validated model for economic evaluations in osteoporosis was used to estimate the cost per quality-adjusted life-year (QALY) gained of vitamin D/calcium supplementation compared with no treatment. The model was populated with cost and epidemiological data from a Belgian health-care perspective. Analyses were conducted in women and men with a diagnosis of osteoporosis (i.e. bone mineral density T-score </=-2.5). A literature search was conducted to describe the efficacy of vitamin D and calcium in terms of fracture risk reduction. RESULTS: The cost per QALY gained of vitamin D/calcium supplementation was estimated at euro40 578 and euro23 477 in women and men aged 60 years, respectively. These values decreased to euro7912 and euro10 250 at the age of 70 years and vitamin D and calcium supplementation was cost-saving at the age of 80 years, meaning that treatment cost was less than the costs of treating osteoporotic fractures of the no-treatment group. CONCLUSION: This study suggests that vitamin D and calcium supplementation is cost-effective for women and men with osteoporosis aged over 60 years. From an economic perspective, vitamin D and calcium should therefore be administrated in these populations including those also taking other osteoporotic treatments

Comparison of a simple clinical risk index and quantitative bone ultrasound for identifying women at increased risk of osteoporosis

Osteoporosis is a growing problem in Asia, and early identification of at risk subjects for preventive measures is likely the most cost-effective method for managing this disease in developing countries. Patients with low bone mineral density (BMD) have a high risk of future fracture. However, access to BMD measurements is limited in many areas of Asia, and inexpensive methods of targeting high-risk patients for BMD measurements would be valuable. We compared two methods, a simple clinical risk assessment tool, the Osteoporosis Self-assessment Tool for Asians (OSTA), and quantitative bone ultrasound (QUS) in identifying subjects with low BMD by DXA in 722 southern Chinese postmenopausal women recruited from the community in Hong Kong. Using the published cutoff value of -1 (versus 0 or higher) for OSTA to identify subjects with femoral neck BMD T-score less than or equal to-2.5, basing on our local population peak young mean value, the sensitivity and specificity was 88% and 54% respectively. The optimal cutoff T-score of -2.35 for QUS yielded sensitivity and specificity values of 81% and 65%, respectively. The AUC for QUS was 0.78, which was not significantly different from that of 0.80 for OSTA. Both OSTA and QUS correlated significantly with BMD at the femoral neck (0.62 and 0.36, respectively, P both <0.001). When these cut-off values were used to identify subjects with either lumbar spine or femoral neck BMD T-score less than or equal to-2.5, the sensitivity and specificity was 79% and 60%, respectively, for OSTA, and 69% and 70%, respectively, for QUS. Combining QUS with OSTA improved the sensitivity to 91%, but the specificity was reduced to 44%. We conclude that the simple clinical risk assessment tool OSTA is a free and effective method for identifying subjects at increased risk of osteoporosis, and its use could facilitate the appropriate and more cost-effective use of bone densitometry in developing countries

Validation and comparative evaluation of the osteoporosis self-assessment tool (OST) in a Caucasian population from Belgium

BACKGROUND: Risk indices have been developed to identify women at risk of low bone mineral density (BMD) who should undergo BMD testing. Aim: To compare the performance of four risk indices in White ambulatory women in Belgium. DESIGN: Epidemiological cross-sectional study. METHODS: Records were analysed for 4035 postmenopausal White women without Paget's disease or advanced osteoarthritis, seen at an out-patient osteoporosis centre between January 1996 and September 1999. Osteoporosis risk index scores were compared to bone density T-scores. The ability of each risk index to identify women with low BMD (T-score < -2.0) or osteoporosis (T < -2.5) was evaluated. RESULTS: Using an Osteoporosis Self-Assessment Tool (OST) score <2 to recommend DXA referral, sensitivity ranged from 85% at the lumbar spine to 97% at the total hip to detect BMD T-scores of <or= -2.5, and specificity ranged from 34% at the total hip to 37% at the femoral neck and lumbar spine. The negative predictive value was high at all skeletal sites (89-99%), demonstrating the usefulness of the OST to identify patients who have normal BMD and should not receive DXA testing. All risk indices performed similarly, although the OST had somewhat better sensitivity and somewhat lower specificity than the other indices at the cut-offs evaluated. Among the 11-12% of women who were classified as highest risk using OST or the Osteoporosis Index of Risk (OSIRIS), 81-85% had low bone mass and 68-74% had osteoporosis. DISCUSSION: The performance of these risk indices among women in Belgium was similar to that reported earlier for other samples in Asian countries, the US, and the Netherlands. The OST and other risk indices are effective and efficient tools to help target high-risk women for DXA testing

Synthesis of 3-[(2-amino-1,2-dicyanovinyl)amino]-2-(benzoylamino)propenoates

Synthesis of 3-(2-amino-1,2-dicyanovinyl)amino-2-(benzoylamino)propenoate

Infrared to vacuum-ultraviolet ellipsometry and optical Hall-effect study of free-charge carrier parameters in Mg-doped InN

Infrared to vacuum-ultraviolet spectroscopic ellipsometry and far-infrared optical Hall-effect measurements are applied to conclude on successful p-type doping of InN films. A representative set of In-polar Mg-doped InN films with Mg concentrations ranging from 1.2 x 10(16) cm(-3) to 3.9 x 10(21) cm(-3) is investigated. The data are compared and discussed in dependence of the Mg concentration. Differences between n-type and p-type conducting samples are identified and explained. p-type conductivity in the Mg concentration range between 1.1 x 10(18) cm(-3) and 2.9 x 10(19) cm(-3) is indicated by the appearance of a dip structure in the infrared spectral region related to a loss in reflectivity of p-polarized light as a consequence of reduced LO phonon plasmon coupling, by vanishing free-charge carrier induced birefringence in the optical Hall-effect measurements, and by a sudden change in phonon-plasmon broadening behavior despite continuous change in the Mg concentration. By modeling the near-infrared-to-vacuum-ultraviolet ellipsometry data, information about layer thickness, electronic interband transitions, as well as surface roughness is extracted in dependence of the Mg concentration. A parameterized model that accounts for the phonon-plasmon coupling is applied for the infrared spectral range to determine the free-charge carrier concentration and mobility parameters in the doped bulk InN layer as well as the GaN template and undoped InN buffer layer. The optical Hall-effect best-match model parameters are consistent with those obtained from infrared ellipsometry analysis.Funding Agencies|National Science Foundation|MRSEC DMR-0820521MRI DMR-0922937DMR-0907475EPS-1004094|Swedish Research Council (VR)|2010-3848|Swedish Governmental Agency for Innovation Systems (VINNOVA) under the VINNMER International Qualification program|2011-03486|FCT Portugal|PTDC/FIS/100448/2008|</p