285 research outputs found

    Modeling and analysis of magnetic hybrid nanoparticle (Au-Al2O3/blood) based drug delivery through a bell-shaped occluded artery with Joule heating, viscous dissipation and variable viscosity effects

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    The present work deals with the impact of hybrid nanoparticles (Au-Al2O3/Blood) on the blood flow pattern through a porous cylindrical artery with bell-shaped stenosis in the presence of an external magnetic field, Joule heating, and viscous dissipation by considering twodimensional pulsatile blood flow. The temperature-dependent viscosity model is utilized in this model. The blood flow is assumed to be unsteady, laminar, viscous, and incompressible. The mild stenotic presumption normalizes and reduces the bi-directional flow to uni-directional. The Crank-Nicolson scheme is applied to solve the continuity, momentum, and energy equations with appropriate initial and boundary conditions. The acquired results of the work are presented graphically. They have been examined for several values of the dimensionless parameters such as Magnetic number (M2 ), Darcy number (Da), Grashof number (Gr), viscosity parameter (β0), Reynolds number (Re), Eckert Number (Ec), Prandtl number (Pr), different concentration of both the nanoparticles (φ1, φ2), and pressure gradient parameter (B1). The velocity contours for different emerging parameters have been drawn to analyze the overall behavior of blood flow patterns. The non-dimensional velocity profile enhances with increment in values of Da, implying that the medium’s permeability provides less barrier to flow. The cumulative impact of Joule Heating and viscous dissipation are discussed. It demonstrates that increasing viscous dissipation (Ec) and Joule heating (M2 ) parameter simultaneously raise the nanofluid temperature since the mechanical energy is transformed to thermal energy within molecules, which causes a hike in temperature. The findings reveal that hybrid nanoparticles (Au-Al2O3/blood) effectively reduce hemodynamic variables such as wall shear stress and resistance impedance. Results indicate that nanoparticles may be helpful to keep the blood velocity under control and allow the surgeons to adjust it as and when required. The present work aims to get insight into the treatment of atherosclerosis without surgery, lower medical costs, and reduce post-surgical complications. Also, it has broad implications in treating various conditions, including cancers, infections, and the removal of blood clots. The current findings are consistent with recent findings in earlier blood flow research studies

    SEM Analysis of MTAD Efficacy for Smear Layer Removal from Periodontally Affected Root Surfaces

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    Objective: Biopure® MTAD (Dentsply Tulsa Dental, USA) has been developedas a final irrigant following root canal shaping to remove intracanal smear layer.Many of the unique properties of MTAD potentially transfer to the conditioningprocess of tooth roots during periodontal therapy. The aim of this ex vivo studywas to evaluate the effect of MTAD on the removal of smear layer from root surfaces.Materials and Methods: Thirty two longitudinally sectioned specimens from 16freshly extracted teeth diagnosed with advanced periodontal disease were dividedinto four groups. In group 1 and 2, the root surfaces were scaled using Gracey curettes.In group 3 and 4, 0.5 mm of the root surface was removed using a fissurebur. The specimens in group 1 and 3 were then irrigated by normal saline. Thespecimens in groups 2 and 4 were irrigated with Biopure MTAD.All specimens were prepared for SEM and scored according to the presence ofsmear layer.Results: MTAD significantly increased (P=0.001) the smear layer removal inboth groups 2 and 4 compared to the associated control groups, in which only salinewas used.Conclusion: MTAD increased the removal of the smear layer from periodontallyaffected root surfaces. Use of MTAD as a periodontal conditioner may be suggeste

    One-pot, three-component synthesis of novel δ-sultam scaffolds via N-sulfonylation—intramolecular Michael sequences.

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    The synthesis of novel δ-sultam scaffolds utilizing one-pot, three-component reactions of 1,3-dicarbonyl compounds, primary aliphatic amines and substituted styrenesulfonyl chlorides is reported. A variety of six-membered sultams are obtained in moderate to good yields presumably via N-sulfonylation—intramolecular Michael addition sequences

    Probing Grand Unified Theories with Cosmic Ray, Gamma-Ray and Neutrino Astrophysics

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    We explore scenarios where the highest energy cosmic rays are produced by new particle physics near the grand unification scale. Using detailed numerical simulations of extragalactic nucleon, gamma-ray, and neutrino propagation, we show the existence of an interesting parameter range for which such scenarios may explain part of the data and are consistent with all observational constraints. A combination of proposed observatories for ultra-high energy cosmic rays, neutrino telescopes of a few kilometer scale, and gamma-ray astrophysics instruments should be able to test these scenarios. In particular, for neutrino masses in the eV range, exclusive neutrino decay modes of superheavy particles can give rise to neutrino fluxes comparable to those predicted in models of active galactic nuclei.Comment: 15 latex pages, 5 postscript figures included, uses revtex.sty and psfig.sty. Submitted to Physical Review

    A comparison of the illness beliefs of people with angina and their peers: a questionnaire study

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    BACKGROUND: What people believe about their illness may affect how they cope with it. It has been suggested that such beliefs stem from those commonly held within society . This study compared the beliefs held by people with angina, regarding causation and coping in angina, with the beliefs of their friends who do not suffer from angina. METHODS: Postal survey using the York Angina Beliefs Questionnaire (version 1), which elicits stress attributions and misconceived beliefs about causation and coping. This was administered to 164 people with angina and their non-cohabiting friends matched for age and sex. 132 people with angina and 94 friends completed the questionnaire. RESULTS: Peers are more likely than people with angina to believe that angina is caused by a worn out heart (p <0.01), angina is a small heart attack (p = 0.02), and that it causes permanent damage to the heart (p <0.001). Peers were also more likely to believe that people with angina should take life easy (p <0.01) and avoid exercise (p = 0.04) and excitement (p <0.01). CONCLUSIONS: The beliefs of the peer group about causation and coping in angina run counter to professional advice. Over time this may contribute to a reduction in patient concordance with risk factor reduction, and may help to create cardiac invalids

    Significant CD4, CD8, and CD19 Lymphopenia in Peripheral Blood of Sarcoidosis Patients Correlates with Severe Disease Manifestations

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    BACKGROUND: Sarcoidosis is a poorly understood chronic inflammatory condition. Infiltration of affected organs by lymphocytes is characteristic of sarcoidosis, however previous reports suggest that circulating lymphocyte counts are low in some patients with the disease. The goal of this study was to evaluate lymphocyte subsets in peripheral blood in a cohort of sarcoidosis patients to determine the prevalence, severity, and clinical features associated with lymphopenia in major lymphocyte subsets. METHODOLOGY/PRINCIPAL FINDINGS: Lymphocyte subsets in 28 sarcoid patients were analyzed using flow cytometry to determine the percentage of CD4, CD8, and CD19 positive cells. Greater than 50% of patients had abnormally low CD4, CD8, or CD19 counts (p<4x10(-10)). Lymphopenia was profound in some cases, and five of the patients had absolute CD4 counts below 200. CD4, CD8, and CD19 lymphocyte subset counts were significantly correlated (Spearman's rho 0.57, p = 0.0017), and 10 patients had low counts in all three subsets. Patients with severe organ system involvement including neurologic, cardiac, ocular, and advanced pulmonary disease had lower lymphocyte subset counts as a group than those patients with less severe manifestations (CD4 p = 0.0043, CD8 p = 0.026, CD19 p = 0.033). No significant relationships were observed between various medical therapies and lymphocyte counts, and lymphopenia was present in patients who were not receiving any medical therapy. CONCLUSIONS/SIGNIFICANCE: Significant lymphopenia involving CD4, CD8, and CD19 positive cells was common in sarcoidosis patients and correlated with disease severity. Our findings suggest that lymphopenia relates more to disease pathology than medical treatment

    SEM analysis of MTAD efficacy for smear layer removal from periodontally affected root surfaces

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    Objective: Biopure® MTAD (Dentsply Tulsa Dental, USA) has been developedas a final irrigant following root canal shaping to remove intracanal smear layer.Many of the unique properties of MTAD potentially transfer to the conditioningprocess of tooth roots during periodontal therapy. The aim of this ex vivo studywas to evaluate the effect of MTAD on the removal of smear layer from root surfaces.Materials and Methods: Thirty two longitudinally sectioned specimens from 16freshly extracted teeth diagnosed with advanced periodontal disease were dividedinto four groups. In group 1 and 2, the root surfaces were scaled using Gracey curettes.In group 3 and 4, 0.5 mm of the root surface was removed using a fissurebur. The specimens in group 1 and 3 were then irrigated by normal saline. Thespecimens in groups 2 and 4 were irrigated with Biopure MTAD.All specimens were prepared for SEM and scored according to the presence ofsmear layer.Results: MTAD significantly increased (P=0.001) the smear layer removal inboth groups 2 and 4 compared to the associated control groups, in which only salinewas used.Conclusion: MTAD increased the removal of the smear layer from periodontallyaffected root surfaces. Use of MTAD as a periodontal conditioner may be suggeste
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