924 research outputs found

    Inclusion of an arbitrary polygon with graded eigenstrain in an anisotropic piezoelectric half plane

    Get PDF
    AbstractThis paper presents an exact closed-form solution for the Eshelby problem of a polygonal inclusion with graded eigenstrains in an anisotropic piezoelectric half plane with traction-free on its surface. Using the line-source Green’s function, the line integral is carried out analytically for the linear eigenstrain case, with the final expression involving only elementary functions. The solutions are applied to the semiconductor quantum wire (QWR) of square, triangular, and rectangular shapes, with results clearly illustrating various influencing factors on the induced fields. The exact closed-form solution should be useful to the analysis of nanoscale QWR structures where large strain and electric fields could be induced by the non-uniform misfit strain

    Research at MIT on high frequency gyrotrons for ECRH

    Get PDF

    Sustainable Supply Chain Management with NGOs, NPOs, and Charity Organizations: A Systematic Review and Research Agenda

    Get PDF
    With the gradually increased awareness of sustainability development, external organizations, including non-governmental organizations (NGOs), non-profit organizations (NPOs), and charity organizations, play an increasingly crucial role in sustainable supply chain management (SSCM). The participation of external organizations not only helps the firms to improve reputation, but also regulates and improves their SSCM. Based on this motivation, we identify the major research domains and examine each domain's evolution by using the objective review methods, including Citation Network Analysis and Main Path Analysis in this literature review paper. Five research domains are recognized, namely, “sustainable supply chain framework design”, “supply chain coordination/collaboration”, “closed-loop supply chain”, “regulation”, and “subsidy and donation”. We review the most influential papers in each research domain to show the evolution of these studies. Based on our review findings, we successfully propose four future research agendas with eight specific issues and innovatively establish a new research framework. The outputs of this review paper can guide the researchers on future search topics and contribute to the development of SSCM with the consideration of organizations.</p

    Grooming of Dynamic Traffic in WDM Star and Tree Networks Using Genetic Algorithm

    Full text link
    The advances in WDM technology lead to the great interest in traffic grooming problems. As traffic often changes from time to time, the problem of grooming dynamic traffic is of great practical value. In this paper, we discuss dynamic grooming of traffic in star and tree networks. A genetic algorithm (GA) based approach is proposed to support arbitrary dynamic traffic patterns, which minimizes the number of ADM's and wavelengths. To evaluate the algorithm, tighter bounds are derived. Computer simulation results show that our algorithm is efficient in reducing both the numbers of ADM's and wavelengths in tree and star networks.Comment: 15 page

    Health service management study for stroke : A randomized controlled trial to evaluate two models of stroke care

    Get PDF
    Background: The most effective and efficient model for providing organized stroke care remains uncertain. This study aimed to compare the effect of two models in a randomized controlled trial. Methods: Patients with acute stroke were randomized on day one of admission to combined, co-located acute/rehabilitation stroke care or traditionally separated acute/rehabilitation stroke care. Outcomes measured at baseline and 90 days post-discharge included functional independence measure, length of hospital stay, and functional independence measure efficiency (change in functional independence measure score ÷ total length of hospital stay). Results: Among 41 patients randomized, 20 were allocated co-located acute/rehabilitation stroke care and 21 traditionally separated acute/rehabilitation stroke care. Baseline measurements showed no significant difference. There was no significant difference in functional independence measure scores between the two groups at discharge and again at 90 days postdischarge (co-located acute/rehabilitation stroke care: 103·6 ± 22·2 vs. traditionally separated acute/rehabilitation stroke care: 99·5 ± 27·7; P = 0·77 at discharge; co-located acute/rehabilitation stroke care: 109·5 ± 21·7 vs. traditionally separated acute/rehabilitation stroke care: 104·4 ± 27·9; P= 0·8875 at 90 days post-discharge). Total length of hospital stay was 5·28 days less in co-located acute/rehabilitation stroke care compared with traditionally separated acute/rehabilitation stroke care (24·15 ± 3·18 vs. 29·42 ± 4·5, P = 0·35). There was significant improvement in functional independence measure efficiency score among participants assigned to co-located acute/rehabilitation stroke care compared with traditionally separated acute/rehabilitation stroke care (co-located acute/rehabilitation stroke care: median 1·60, interquartile range: 0·87–2·81; traditionally separated acute/rehabilitation stroke care: median 0·82, interquartile range: 0·27–1·57, P = 0·0393). Linear regression analysis revealed a high inverse correlation (R2 = 0·89) between functional independence measure efficiency and time spent in the acute stroke unit. Conclusion: This proof-of-concept study has shown that co-located acute/rehabilitation stroke care was just as effective as traditionally separated acute/rehabilitation stroke care as reflected in functional independence measure scores, but significantly more efficient as shown in greater functional independence measure efficiency. Co-located acute/rehabilitation stroke care has potential for significantly improved hospital bed utilization with no patient disadvantage

    Adiponectin Prevents Diabetic Premature Senescence of Endothelial Progenitor Cells and Promotes Endothelial Repair by Suppressing the p38 MAP Kinase/p16INK4A Signaling Pathway

    Get PDF
    OBJECTIVE - A reduced number of circulating endothelial progenitor cells (EPCs) are casually associated with the cardiovascular complication of diabetes. Adiponectin exerts multiple protective effects against cardiovascular disease, independent of its insulin-sensitizing activity. The objective of this study was to investigate whether adiponectin plays a role in modulating the bioavailability of circulating EPCs and endothelial repair. RESEARCH DESIGN AND METHODS - Adiponectin knockout mice were crossed with db+/- mice to produce db/db diabetic mice without adiponectin. Circulating number of EPCs were analyzed by flow cytometry. Reendothelialization was evaluated by staining with Evans blue after wire-induced carotid injury. RESULTS - In adiponectin knockout mice, the number of circulating EPCs decreased in an age-dependent manner compared with the wild-type controls, and this difference was reversed by the chronic infusion of recombinant adiponectin. In db/db diabetic mice, the lack of adiponectin aggravated the hyperglycemia-induced decrease in circulating EPCs and also diminished the stimulatory effects of the PPARγ agonist rosiglitazone on EPC production and reendothelialization. In EPCs isolated from both human peripheral blood and mouse bone marrow, treatment with adiponectin prevented high glucose-induced premature senescence. At the molecular level, adiponectin decreased high glucose-induced accumulation of intracellular reactive oxygen species and consequently suppressed activation of p38 MAP kinase (MAPK) and expression of the senescence marker p16INK4A. CONCLUSIONS - Adiponectin prevents EPC senescence by inhibiting the ROS/p38 MAPK/p16 INK4A signaling cascade. The protective effects of adiponectin against diabetes vascular complications are attributed in part to its ability to counteract hyperglycemia-mediated decrease in the number of circulating EPCs. © 2010 by the American Diabetes Association.published_or_final_versio

    Patients with refractory cytomegalovirus (CMV) infection following allogeneic haematopoietic stem cell transplantation are at high risk for CMV disease and non-relapse mortality

    Get PDF
    AbstractPre-emptive therapy is an effective approach for cytomegalovirus (CMV) control; however, refractory CMV still occurs in a considerable group of recipients after allogeneic haematopoietic stem cell transplantation (allo-HSCT). Until now, hardly any data have been available about the clinical characteristics and risk factors of refractory CMV, or its potential harmful impact on the clinical outcome following allo-HSCT. We studied transplant factors affecting refractory CMV in the 100 days after allo-HSCT, and the impact of refractory CMV on the risk of CMV disease and non-relapse mortality (NRM). We retrospectively studied 488 consecutive patients with CMV infection after allo-HSCT. Patients with refractory CMV in the 100 days after allo-HSCT had a higher incidence of CMV disease and NRM than those without refractory CMV (11.9% vs. 0.8% and 17.1% vs. 8.3%, respectively). Multivariate analysis showed that refractory CMV infection in the 100 days after allo-HSCT was an independent risk factor for CMV disease (hazard ratio (HR) 10.539, 95% CI 2.467–45.015, p 0.001), and that refractory CMV infection within 60–100 days after allo-HSCT was an independent risk factor for NRM (HR 8.435, 95% CI 1.511–47.099, p 0.015). Clinical factors impacting on the risk of refractory CMV infection included receiving transplants from human leukocyte antigen-mismatched family donors (HR 2.012, 95% CI 1.603–2.546, p <0.001) and acute graft-versus-host disease (HR 1.905, 95% CI 1.352–2.686, p <0.001). We conclude that patients with refractory CMV infection during the early stage after allo-HSCT are at high risk for both CMV disease and NRM

    Probing interaction and spatial curvature in the holographic dark energy model

    Full text link
    In this paper we place observational constraints on the interaction and spatial curvature in the holographic dark energy model. We consider three kinds of phenomenological interactions between holographic dark energy and matter, i.e., the interaction term QQ is proportional to the energy densities of dark energy (ρΛ\rho_{\Lambda}), matter (ρm\rho_{m}), and matter plus dark energy (ρm+ρΛ\rho_m+\rho_{\Lambda}). For probing the interaction and spatial curvature in the holographic dark energy model, we use the latest observational data including the type Ia supernovae (SNIa) Constitution data, the shift parameter of the cosmic microwave background (CMB) given by the five-year Wilkinson Microwave Anisotropy Probe (WMAP5) observations, and the baryon acoustic oscillation (BAO) measurement from the Sloan Digital Sky Survey (SDSS). Our results show that the interaction and spatial curvature in the holographic dark energy model are both rather small. Besides, it is interesting to find that there exists significant degeneracy between the phenomenological interaction and the spatial curvature in the holographic dark energy model.Comment: 11 pages, 5 figures; to appear in JCA

    Statefinder Description in Generalized Holographic and Ricci Dark Energy Models

    Full text link
    We have considered the generalized holographic and generalized Ricci dark energy models for acceleration of the universe. If the universe filled with only GHDE/GRDE the corresponding decel- eration parameter, EOS parameter and statefinder parameters have been calculated. Next we have considered that the mixture of GHDE/GRDE and dark matter in interacting and non-interacting situations. Also the mixture of GHDE/GRDE and generalized Chaplygin gas have been analyzed during evolution of the universe. The natures of above mentioned parameters have been investigated for interacting and non-interacting situations. Finally, it follows that the prescribed models derive the acceleration of the universe.Comment: 18 pages and 19 figure
    corecore