| 28601. |
- Kanis, John A, et al.
(författare)
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The distribution of FRAX(®)-based probabilities in women from Japan.
- 2012
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Ingår i: Journal of Bone and Mineral Metabolism. - : Springer Science and Business Media LLC. - 1435-5604 .- 0914-8779. ; 30:6, s. 700-5
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Tidskriftsartikel (refereegranskat)abstract
- New assessment guidelines for osteoporosis in Japan include the use of the WHO risk assessment tool (FRAX) that computes the 10-year probability of fracture. The aim of this study was to determine the distribution of fracture probabilities and to assess the impact of probability-based intervention thresholds in women from Japan aged 50 years and older. Age-specific simulation cohorts were constructed from the prevalences of clinical risk factors and femoral neck bone mineral density to determine the distribution of fracture probabilities as assessed by FRAX. These data were used to estimate the number and proportion of women at or above a 10-year fracture probability of 5, 10, 15, 20, 25, and 30 %. In addition, case scenarios that applied a FRAX probability threshold of 15 % were compared with current guidance. In the absence of additional criteria for treatment, a 15 % fracture probability threshold would identify approximately 32 % of women over the age of 50 years (9.3 million women) as eligible for treatment. Because of expected changes in population demography, the 15 % fracture probability threshold would capture approximately 38 % of women over the age of 50 years (12.7 million women), mainly those aged 80 years or older. The introduction of a FRAX threshold of 15 % would permit treatment in women with clinical risk factors that would otherwise fall below previously established intervention thresholds. The incorporation of FRAX into assessment guidelines is likely to redirect treatments for osteoporosis from younger women at low risk to elderly women at high fracture risk.
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| 28602. |
- Kanis, J A, et al.
(författare)
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The effects of a FRAX revision for the USA.
- 2010
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Ingår i: Osteoporosis International. - : Springer Science and Business Media LLC. - 0937-941X .- 1433-2965. ; 21:1, s. 35-40
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Tidskriftsartikel (refereegranskat)abstract
- A revision (version 3.0) of the fracture risk assessment tool (FRAX) is developed based on an update of epidemiological information for the USA. With the revised tool, there were strong correlations (r > 0.99) between versions 2.0 and 3.0 for FRAX estimates of fracture probability, but the revised models gave lower probability estimates. INTRODUCTION: The aim of this study was to determine the effects of a revision of the epidemiological data used to compute fracture probabilities in the USA with FRAX. METHODS: Models were constructed to compute fracture probabilities based on updated fracture incidence and mortality rates in the USA. The models comprised the ten-year probability of hip fracture and the ten-year probability of a major osteoporotic fracture, both including femoral neck bone mineral density (BMD). For each model, fracture and death hazards were computed as continuous functions. The effect of the revised rates on fracture probability was examined by piecewise linear regression using multiple combinations of clinical risk factors and BMD. RESULTS: At all ages, there was a strong correlation (r > 0.99) between version 2.0 and revised FRAX estimates of fracture probability. For a major osteoporotic fracture, the revised model gave lower median probabilities by 13% to 24% in men, depending on age, and by 19% to 24% in women. For hip fracture probability, the revised model gave lower median fracture probabilities by 40% and 27% at the ages of 50 and 60 years in men and by 43% and 30%, respectively, in women. At the ages of 70 years and older the revised model gave similar hip fracture probabilities as version 2.0 in both men and women. CONCLUSION: The revised FRAX model for the USA (version 3.0) does not alter the ranking of fracture probabilities but provides lower probability estimates than version 2.0, particularly, in younger women and men.
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| 28603. |
- Kanis, J A, et al.
(författare)
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The use of clinical risk factors enhances the performance of BMD in the prediction of hip and osteoporotic fractures in men and women.
- 2007
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Ingår i: Osteoporosis international. - : Springer Science and Business Media LLC. - 0937-941X .- 1433-2965. ; 18:8, s. 1033-46
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Tidskriftsartikel (refereegranskat)abstract
- SUMMARY: BMD and clinical risk factors predict hip and other osteoporotic fractures. The combination of clinical risk factors and BMD provide higher specificity and sensitivity than either alone. INTRODUCTION AND HYPOTHESES: To develop a risk assessment tool based on clinical risk factors (CRFs) with and without BMD. METHODS: Nine population-based studies were studied in which BMD and CRFs were documented at baseline. Poisson regression models were developed for hip fracture and other osteoporotic fractures, with and without hip BMD. Fracture risk was expressed as gradient of risk (GR, risk ratio/SD change in risk score). RESULTS: CRFs alone predicted hip fracture with a GR of 2.1/SD at the age of 50 years and decreased with age. The use of BMD alone provided a higher GR (3.7/SD), and was improved further with the combined use of CRFs and BMD (4.2/SD). For other osteoporotic fractures, the GRs were lower than for hip fracture. The GR with CRFs alone was 1.4/SD at the age of 50 years, similar to that provided by BMD (GR = 1.4/SD) and was not markedly increased by the combination (GR = 1.4/SD). The performance characteristics of clinical risk factors with and without BMD were validated in eleven independent population-based cohorts. CONCLUSIONS: The models developed provide the basis for the integrated use of validated clinical risk factors in men and women to aid in fracture risk prediction.
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| 28604. |
- Kanis, J A, et al.
(författare)
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The use of multiple sites for the diagnosis of osteoporosis.
- 2006
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Ingår i: Osteoporosis international. - : Springer Science and Business Media LLC. - 0937-941X .- 1433-2965. ; 17:4, s. 527-34
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: It has been suggested that bone mineral density (BMD) measurements should be made at multiple sites, and that the lowest T-score should be taken for the purpose of diagnosing osteoporosis. PURPOSE: The aim of this study was to examine the use of BMD measurements at the femoral neck and lumbar spine alone and in combination for fracture prediction. METHODS: We studied 19,071 individuals (68% women) from six prospective population-based cohorts in whom BMD was measured at both sites and fracture outcomes documented over 73,499 patient years. BMD values were converted to Z-scores, and the gradient of risk for any osteoporotic fracture and for hip fracture was examined by using a Poisson model in each cohort and each gender separately. Results of the different studies were merged using weighted beta-coefficients. RESULTS: The gradients of risk for osteoporotic fracture and for hip fracture were similar in men and women. In men and women combined, the risk of any osteoporotic fracture increased by 1.51 [95% confidence interval (CI)=1.42-1.61] per standard deviation (SD) decrease in femoral-neck BMD. For measurements made at the lumbar spine, the gradient of risk was 1.47 (95% CI=1.38-1.56). Where the minimum of the two values was used, the gradient of risk was similar (1.55; 95% CI=1.45-1.64). Higher gradients of risk were observed for hip fracture outcomes: with BMD at the femoral neck, the gradient of risk was 2.45 (95% CI=2.10-2.87), with lumbar BMD was 1.57 (95% CI=1.36-1.82), and with the minimum value of either femoral neck and lumbar spine was 2.11 (95% CI=1.81-2.45). Thus, selecting the lowest value for BMD at either the femoral neck or lumbar spine did not increase the predictive ability of BMD tests. By contrast, the sensitivity increased so that more individuals were identified but at the expense of specificity. Thus, the same effect could be achieved by using a less stringent T-score for the diagnosis of osteoporosis. CONCLUSIONS: Since taking the minimum value of the two measurements does not improve predictive ability, its clinical utility for the diagnosis of osteoporosis is low.
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| 28605. |
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| 28606. |
- Kankare, E., et al.
(författare)
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SN 2009kn-the twin of the Type IIn supernova 1994W
- 2012
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 424:2, s. 855-873
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Tidskriftsartikel (refereegranskat)abstract
- We present an optical and near-infrared photometric and spectroscopic study of supernova (SN) 2009kn spanning similar to 1.5 yr from the discovery. The optical spectra are dominated by the narrow (full width at half-maximum similar to 1000 km s-1) Balmer lines distinctive of a Type IIn SN with P Cygni profiles. Contrarily, the photometric evolution resembles more that of a Type IIP SN with a large drop in luminosity at the end of the plateau phase. These characteristics are similar to those of SN 1994W, whose nature has been explained with two different models with different approaches. The well-sampled data set on SN 2009kn offers the possibility to test these models, in the case of both SN 2009kn and SN 1994W. We associate the narrow P Cygni lines with a swept-up shell composed of circumstellar matter and SN ejecta. The broad emission line wings, seen during the plateau phase, arise from internal electron scattering in this shell. The slope of the light curve after the post-plateau drop is fairly consistent with that expected from the radioactive decay of 56Co, suggesting an SN origin for SN 2009kn. Assuming radioactivity to be the main source powering the light curve of SN 2009kn in the tail phase, we infer an upper limit for 56Ni mass of 0.023 M?. This is significantly higher than that estimated for SN 1994W, which also showed a much steeper decline of the light curve after the post-plateau drop. We also observe late-time near-infrared emission which most likely arises from newly formed dust produced by SN 2009kn. As with SN 1994W, no broad lines are observed in the spectra of SN 2009kn, not even in the late-time tail phase.
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| 28607. |
- Kann, Nina, 1964
(författare)
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Applications of the Nicholas Reaction in the Synthesis of Natural Products
- 2012
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Ingår i: Current Organic Chemistry. - : Bentham Science Publishers Ltd.. - 1385-2728. ; 16:3, s. 322-334
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Forskningsöversikt (refereegranskat)abstract
- The Nicholas reaction involves the treatment of a cobalt carbonyl-stabilized propargylic cation with a variety of nucleophiles to form a new carbon-carbon or carbon-heteroatom bond. Several features of this reaction make it especially well suited for applications in natural product synthesis, in particular when cyclic and polycyclic target molecules are involved. This review summarizes the results in this area from the last ten years, including approaches towards terpenes, alkaloids and marine natural products.
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| 28608. |
- Kann, Nina, 1964, et al.
(författare)
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Conformational properties of 1,4- and 1,5-substituted 1,2,3-triazole amino acids-building units for peptidic foldamers
- 2015
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Ingår i: Organic and Biomolecular Chemistry. - : Royal Society of Chemistry (RSC). - 1477-0539 .- 1477-0520. ; 13:9, s. 2776-2785
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Tidskriftsartikel (refereegranskat)abstract
- Peptidic foldamers have recently emerged as a novel class of artificial oligomers with properties and structural diversity similar to that of natural peptides, but possessing additional interesting features granting them great potential for applications in fields from nanotechnology to pharmaceuticals. Among these, foldamers containing 1,4- and 1,5-substitued triazole amino acids are easily prepared via the Cu- and Ru-catalyzed click reactions and may offer increased side chain variation, but their structural capabilities have not yet been widely explored. We here describe a systematic analysis of the conformational space of the two most important basic units, the 1,4-substitued (4Tzl) and the 1,5-substitued (5Tzl) 1,2,3-triazole amino acids, using quantum chemical calculations and NMR spectroscopy. Possible conformations of the two triazoles were scanned and their potential minima were located using several theoretical approaches (B3LYP/6-311++G(2d,2p), ωB97X-D/6-311++G(2d,2p), M06-2X/6-311++G(2d,2p) and MP2/6-311++G(2d,2p)) in different solvents. BOC-protected versions of 4Tzl and 5Tzl were also prepared via one step transformations and analyzed by 2D NOESY NMR. Theoretical results show 9 conformers for 5Tzl derivatives with relative energies lying close to each other, which may lead to a great structural diversity. NMR analysis also indicates that conformers preferring turn, helix and zig-zag secondary structures may coexist in solution. In contrast, 4Tzl has a much lower number of conformers, only 4, and these lack strong intraresidual interactions. This is again supported by NMR suggesting the presence of both extended and bent conformers. The structural information provided on these building units could be employed in future design of triazole foldamers.
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| 28609. |
- Kann, Nina, 1964
(författare)
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Recent Applications of Polymer Supported Organometallic Catalysts in Organic Synthesis
- 2010
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Ingår i: Molecules. - : MDPI AG. - 1420-3049 .- 1420-3049. ; 15:9, s. 6306-6331
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Tidskriftsartikel (refereegranskat)abstract
- Recent developments concerning the application of polymer supported organometallic reagents in solid phase synthesis are reviewed, with a special focus on methodology for carbon-carbon formation. Examples of reactions that are covered include the classical Suzuki, Sonogashira and Heck coupings, but also aryl amination, epoxide opening, rearrangements, metathesis and cyclopropanation. Applications in the field of asymmetric synthesis are also discussed.
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| 28610. |
- Kannan, Ananda Subramani, 1989, et al.
(författare)
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A continuum-based multiphase DNS method for studying the Brownian dynamics of soot particles in a rarefied gas
- 2019
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Ingår i: Chemical Engineering Science. - : Elsevier BV. - 0009-2509. ; 210
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Tidskriftsartikel (refereegranskat)abstract
- In the mitigation of particulate matter (PM) using filters, the interplay between particle motion, geometry and flow conditions determines the overall performance. In such flows, molecular effects on the particle motion manifest as impeded momentum transfer and a meandering Brownian motion. Other particles and walls induce hydrodynamic interactions, which may further influence PM nucleation, growth and aggregation. Here, we formulate a multiphase direct numerical simulation framework to investigate these complex flows by including the molecular interactions in a consistent manner. The basis for this framework is a coupling between the Langevin description of particle motion with a mirroring immersed boundary method. We show that the method is able to capture the diffusion dynamics of a Brownian particle, including its transition from a particle-inertia dominated, correlated ballistic regime to a non-correlated diffusive one, and that the method also can be used to reproduce the meandering motion of realistic soot particles.
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