519 research outputs found

    Quantitative analysis of TM lateral leakage in foundry fabricated silicon Rib waveguides

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    We show that thin, shallow ridge, silicon-on-insulator waveguides exhibiting a lateral leakage behavior can be designed and fabricated using a standard silicon photonic foundry platform. We analyze the propagation loss through the observation of the transmitted TM polarized guided mode and TE polarized radiation and experimentally demonstrate that propagation losses as low as 0.087 dB/mm can be achieved. This demonstration will open a new frontier for practical devices exploiting a lateral leakage behavior with potential applications in the fields of biosensing and quantum optics among others

    Research Issues in Fine Arts Marketing

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    Mathematical programs with a two-dimensional reverse convex constraint

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    We consider the problem min{f(χ) : χ ∈ G, T(χ) ∉ int D}, where f is a lower semicontinuous function, G a compact, nonempty set in IRn, D a closed convex set in JR² with nonempty interior, and T a continuous mapping from IRn to IR². The constraint T(χ) ∉. int D is areverse convex constraint, so the feasible domain may be disconnected even when f, T are affine and G is a polytope. We show that this problem can be reduced to a quasiconcave minimization problem over a compact convex set in IR², and hence can be solved effectively provided f, T are convex and G is convex or discrete. In particular, we discuss areverse convex constraint of the form (c, χ) . (d, χ) ≤ 1. We also compare the approach in this paper with the parametric approach

    A Fine Arts Marketing Elective: Justification of Need and Proposed Course Content

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    This paper explains the need for a marketing elective course that would address the business field of fine arts marketing with an emphasis on visual arts including painting in various media including drawings and print reproductions, photography, and sculpture. The proposed course would be intended for general business students, marketing majors, and fine arts majors. The paper first reviews the overall business impact of fine arts marketing from a global business and United States perspective. The paper then suggests major topics and readings that would be included in such a course and the order in which these topics might be presented. These topics include the unique marketing situation of fine arts as an industry area with reference to motivation and perceptions of fine arts artists regarding the concept of marketing exchange, the nature of fine arts as an opaque market, the structure of the industry by which fine art is produced and brought to the public, and specific techniques that fine arts artists might utilize to promote their work and themselves so as to build brand value. Finally, specific student projects are suggested including field visits and the development of marketing plans for professionally oriented artists

    Reduced mortality and subsequent fracture risk associated with oral bisphosphonate recommendation in a fracture liaison service setting: A prospective cohort study

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    Objective: Osteoporotic fragility fractures, that are common in men and women, signal increased risk of future fractures and of premature mortality. Less than one-third of postmenopausal women and fewer men are prescribed active treatments to reduce fracture risk. Therefore, in this study the association of oral bisphosphonate recommendation with subsequent fracture and mortality over eight years in a fracture liaison service setting was analysed. Materials and methods: In this prospective cohort study, 5011 men and women aged \u3e50 years, who sustained a clinical fracture, accepted the invitation to attend the fracture liaison service of the West Glasgow health service between 1999 and 2007. These patients were fully assessed and all were recommended calcium and vitamin D. Based on pre-defined fracture risk criteria, 2534 (50.7%) patients were additionally also recommended oral bisphosphonates. Mortality and subsequent fracture risk were the pre-defined outcomes analysed using Cox proportional hazard models. Results: Those recommended bisphosphonates were more often female (82.9 vs. 72.4%), were older (73.4 vs. 64.4 years), had lower bone mineral density T-score (-3.1 vs. -1.5) and more had sustained hip fractures (21.7 vs. 6.2%; p \u3c 0.001). After adjustments, patients recommended bisphosphonates had lower subsequent fracture risk (Hazard Ratio (HR): 0.60; 95% confidence interval (CI): 0.49±0.73) and lower mortality risk (HR: 0.79, 95%CI: 0.64±0.97). Conclusion: Of the patients, who are fully assessed after a fracture at the fracture liaison service, those with higher fracture risk and a recommendation for bisphosphonates had worse baseline characteristics. However, after adjusting for these differences, those recommended bisphosphonate treatment had a substantially lower risk for subsequent fragility fracture and lower risk for mortality. These community-based data indicate the adverse public health outcomes and mortality impacts of the current low treatment levels post fracture could be improved by bisphosphonate recommendation for both subsequent fracture and mortality

    Cellular and molecular pathology of age-related macular degeneration: Potential role for proteoglycans

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    Age-related macular degeneration (AMD) is a retinal disease evident after the age of 50 that damages the macula in the centre of retina. It leads to a loss of central vision with retained peripheral vision but eventual blindness occurs in many cases. The initiation site of AMD development is Bruch's membrane (BM) where multiple changes occur including the deposition of plasma derived lipids, accumulation of extracellular debris, changes in cell morphology, and viability and the formation of drusen. AMD manifests as early and late stage; the latter involves cell proliferation and neovascularization in wet AMD. Current therapies target the later hyperproliferative and invasive wet stage whilst none target early developmental stages of AMD. In the lipid deposition disease atherosclerosis modified proteoglycans bind and retain apolipoproteins in the artery wall. Chemically modified trapped lipids are immunogenic and can initiate a chronic inflammatory process manifesting as atherosclerotic plaques and subsequent artery blockages, heart attacks, or strokes. As plasma derived lipoprotein deposits are found in BM in early AMD, it is possible that they arise by a similar process within the macula. In this review we consider aspects of the pathological processes underlying AMD with a focus on the potential role of modifications to secreted proteoglycans being a cause and therefore a target for the treatment of early AMD

    Reduction in both seasonal mortality and longer term mortality trends following restrictions on the sulphur content of fuel oil in Hong Kong (Abstract)

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    Temperature as a modifier of the effects of fine particulate matter on acute mortality in Hong Kong

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    Interactions between particulate matter with aerodynamic diameter less than or equal to 2.5 μm (PM2.5) and temperature on mortality have not been well studied, and results are difficult to synthesize. We aimed to assess modification of temperature on the association between PM2.5 and cause-specific mortality by stratifying temperature into low, medium, and high stratum in Hong Kong, using data from 1999 to 2011. The mortality effects of PM2.5 were stronger in low temperature stratum than those in high. The excess risk (%) per 10 μg/m3 increase in PM2.5 at lag 0–1 in low temperature stratum were 0.94% (95% confidence interval: 0.65, 1.24) for all natural, 0.88% (0.38, 1.37) for cardiovascular, and 1.15% (0.51, 1.79) for respiratory mortality. We found statistically significant interaction of PM2.5 and temperature between low and high temperature stratum for all natural mortality. Our results suggested that temperature might modify mortality effects of PM2.5 in Hong Kong.postprin

    Platelet-derived growth factor-stimulated versican synthesis but not glycosaminoglycan elongation in vascular smooth muscle is mediated via Akt phosphorylation

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    Proteoglycans are associated with the initiation of atherosclerosis due to their binding of apolipoproteins on lipid particles leading to retention in the vessel wall. The signaling pathways through which growth factors regulate the synthesis and structure of proteoglycans are potential therapeutic targets. Platelet-derived growth factor (PDGF) is present in atherosclerotic plaques and activates phosphorylation of the serine/threonine kinase Akt. We have investigated the role of Akt in the signaling pathways for proteoglycan core protein expression and elongation of glycosaminoglycan chains on proteoglycans secreted by human vascular smooth muscle cells. The pharmacological inhibitor of Akt phosphorylation, SN30978, blocked PDGF stimulated phosphorylation of Akt. SN30978 caused concentration dependent inhibition of PDGF stimulated radiosulfate incorporation into secreted proteoglycans and the response was blocked by the PDGF receptor antagonists Ki11502 and imatinib. Analysis of the size of the biglycan molecules by SDS-PAGE showed that PDGF increased the apparent size of biglycan but this effect on glycosaminoglycan chain elongation was blocked by Ki11502 but not by SN30978. PDGF also stimulated total protein core protein synthesis assessed as 35S-methionine/cysteine incorporation and specifically the expression of versican mRNA. Both of these responses were blocked by SN30978. This data shows that PDGF-stimulated proteoglycan core protein synthesis but not glycosaminoglycan chain elongation is mediated via Akt phosphorylation. These data identify potential pathways for the development of agents which can pharmacologically regulate individual components of the synthesis of proteoglycans

    Resequencing microarray probe design for typing genetically diverse viruses: human rhinoviruses and enteroviruses

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    <p>Abstract</p> <p>Background</p> <p>Febrile respiratory illness (FRI) has a high impact on public health and global economics and poses a difficult challenge for differential diagnosis. A particular issue is the detection of genetically diverse pathogens, i.e. human rhinoviruses (HRV) and enteroviruses (HEV) which are frequent causes of FRI. Resequencing Pathogen Microarray technology has demonstrated potential for differential diagnosis of several respiratory pathogens simultaneously, but a high confidence design method to select probes for genetically diverse viruses is lacking.</p> <p>Results</p> <p>Using HRV and HEV as test cases, we assess a general design strategy for detecting and serotyping genetically diverse viruses. A minimal number of probe sequences (26 for HRV and 13 for HEV), which were potentially capable of detecting all serotypes of HRV and HEV, were determined and implemented on the Resequencing Pathogen Microarray RPM-Flu v.30/31 (<it>Tessarae RPM-Flu</it>). The specificities of designed probes were validated using 34 HRV and 28 HEV strains. All strains were successfully detected and identified at least to species level. 33 HRV strains and 16 HEV strains could be further differentiated to serotype level.</p> <p>Conclusion</p> <p>This study provides a fundamental evaluation of simultaneous detection and differential identification of genetically diverse RNA viruses with a minimal number of prototype sequences. The results demonstrated that the newly designed RPM-Flu v.30/31 can provide comprehensive and specific analysis of HRV and HEV samples which implicates that this design strategy will be applicable for other genetically diverse viruses.</p
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