218 research outputs found

    Performance Analysis of Hierarchical Routing Protocols in Wireless Sensor Networks

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    This work focusses on analyzing the optimization strategies of routing protocols with respect to energy utilization of sensor nodes in Wireless Sensor Network (WSNs). Different routing mechanisms have been proposed to address energy optimization problem in sensor nodes. Clustering mechanism is one of the popular WSNs routing mechanisms. In this paper, we first address energy limitation constraints with respect to maximizing network life time using linear programming formulation technique. To check the efficiency of different clustering scheme against modeled constraints, we select four cluster based routing protocols; Low Energy Adaptive Clustering Hierarchy (LEACH), Threshold Sensitive Energy Efficient sensor Network (TEEN), Stable Election Protocol (SEP), and Distributed Energy Efficient Clustering (DEEC). To validate our mathematical framework, we perform analytical simulations in MATLAB by choosing number of alive nodes, number of dead nodes, number of packets and number of CHs, as performance metrics.Comment: NGWMN with 7th IEEE International Conference on Broadband and Wireless Computing, Communication and Applications (BWCCA 2012), Victoria, Canada, 201

    The Lambek calculus with iteration: two variants

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    Formulae of the Lambek calculus are constructed using three binary connectives, multiplication and two divisions. We extend it using a unary connective, positive Kleene iteration. For this new operation, following its natural interpretation, we present two lines of calculi. The first one is a fragment of infinitary action logic and includes an omega-rule for introducing iteration to the antecedent. We also consider a version with infinite (but finitely branching) derivations and prove equivalence of these two versions. In Kleene algebras, this line of calculi corresponds to the *-continuous case. For the second line, we restrict our infinite derivations to cyclic (regular) ones. We show that this system is equivalent to a variant of action logic that corresponds to general residuated Kleene algebras, not necessarily *-continuous. Finally, we show that, in contrast with the case without division operations (considered by Kozen), the first system is strictly stronger than the second one. To prove this, we use a complexity argument. Namely, we show, using methods of Buszkowski and Palka, that the first system is Π10\Pi_1^0-hard, and therefore is not recursively enumerable and cannot be described by a calculus with finite derivations

    Management of chronic conditions in resource limited settings: multi stakeholders’ perception and experiences with receiving and providing integrated HIV, diabetes and hypertension services in Tanzania

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    Background: The rising prevalence of non-communicable diseases (NCDs) alongside the continuing high burden of HIV poses a serious challenge to middle- and low-income countries’ healthcare systems. Pilot studies of integrated models of service delivery for HIV, hypertension and diabetes have demonstrated that they are feasible and acceptable among patients and care providers. This study assessed multi-stakeholders’ perspectives of the delivery and receipt of integrated care in Tanzania. Methods: A qualitative process evaluation was conducted in Dar es Salaam region of Tanzania where the integrated service delivery model was implemented from July to November 2021. In-depth interviews were held with seven key informants at the national, regional and district levels, eight healthcare providers, two researchers working at the integrated clinic and forty patients benefiting from integrated services at a large hospital. Three focus group discussions were held with community leaders and residents of the hospital’s catchment area, and clinic level observations were conducted. Thematic analysis was conducted followed by the use of Bronfenbrenner’s ecological model to identify factors pertinent to sustaining and scaling up of the integrated model. Results: Participants of the study at all levels were aware of the increased prevalence of NCDs specifically for hypertension and diabetes and were concerned about the trend of increasing co-morbid conditions among people living with HIV (PLHIV). The integrated service delivery model was positively perceived by stakeholders because of its multiple benefits for both patients and the healthcare system. These include stigma and discrimination reduction, improved quality of care, efficient use of limited resources, cost and time saving, reduced duplication of services and fostering of early detection for undiagnosed conditions. The organisation of the clinic was critical in increased satisfaction. Several challenges were observed, which included costs for NCD services relative to free care for HIV and inconsistent availability of NCD medications. Conclusion: Stakeholders reported numerous benefits of the integrated service delivery model that are fundamental in improving the health of many Tanzanians living with NCDs and HIV. These benefits highlight the need for policy and decision-makers to sustain and expand the integrated service delivery model as a solution to many challenges facing the health system especially at the primary care level

    Thermal inactivation and conformational lock studies on glucose oxidase

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    In this study, the dissociative thermal inactivation and conformational lock theories are applied for the homodimeric enzyme glucose oxidase (GOD) in order to analyze its structure. For this purpose, the rate of activity reduction of glucose oxidase is studied at various temperatures using b-D-glucose as the substrate by incubation of enzyme at various temperatures in the wide range between 40 and 70 ïżœC using UV–Vis spectrophotometry. It was observed that in the two ranges of temperatures, the enzyme has two different forms. In relatively low temperatures, the enzyme is in its dimeric state and has normal activity. In high temperatures, the activity almost disappears and it aggregates. The above achievements are confirmed by dynamic light scattering. The experimental parameter ‘‘n’’ as the obvious number of conformational locks at the dimer interface of glucose oxidase is obtained by kinetic data, and the value is near to two. To confirm the above results, the X-ray crystallography structure of the enzyme, GOD (pdb, 1gal), was also studied. The secondary and tertiary structures of the enzyme to track the thermal inactivation were studied by circular dichroism and fluorescence spectroscopy, respectively. We proposed a mechanism model for thermal inactivation of GOD based on the absence of the monomeric form of the enzyme by circular dichroism and fluorescence spectroscopy

    Management of Chronic Conditions in Resource Limited Settings: Multi stakeholders’ perception and experiences with receiving and providing integrated HIV, Diabetes and Hypertension services in Tanzania

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    Background: The rising prevalence of non-communicable diseases (NCDs) alongside the continuing high burden of HIV poses a serious challenge to middle- and low-income countries’ healthcare systems. Pilot studies of integrated models of service delivery for HIV, hypertension and diabetes have demonstrated that they are feasible and acceptable among patients and care providers. This study assessed multi-stakeholders’ perspectives of the delivery and receipt of integrated care in Tanzania. Methods: A qualitative process evaluation was conducted in Dar es Salaam region of Tanzania where the integrated service delivery model was implemented from July to November 2021. In-depth interviews were held with seven key informants at the national, regional and district levels, eight healthcare providers, two researchers working at the integrated clinic and forty patients benefiting from integrated services at a large hospital. Three focus group discussions were held with community leaders and residents of the hospital’s catchment area, and clinic level observations were conducted. Thematic analysis was conducted followed by the use of Bronfenbrenner’s ecological model to identify factors pertinent to sustaining and scaling up of the integrated model. Results: Participants of the study at all levels were aware of the increased prevalence of NCDs specifically for hypertension and diabetes and were concerned about the trend of increasing co-morbid conditions among people living with HIV (PLHIV). The integrated service delivery model was positively perceived by stakeholders because of its multiple benefits for both patients and the healthcare system. These include stigma and discrimination reduction, improved quality of care, efficient use of limited resources, cost and time saving, reduced duplication of services and fostering of early detection for undiagnosed conditions. The organisation of the clinic was critical in increased satisfaction. Several challenges were observed, which included costs for NCD services relative to free care for HIV and inconsistent availability of NCD medications. Conclusion: Stakeholders reported numerous benefits of the integrated service delivery model that are fundamental in improving the health of many Tanzanians living with NCDs and HIV. These benefits highlight the need for policy and decision-makers to sustain and expand the integrated service delivery model as a solution to many challenges facing the health system especially at the primary care level

    GITR signaling potentiates airway hyperresponsiveness by enhancing Th2 cell activity in a mouse model of asthma

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    <p>Abstract</p> <p>Background</p> <p>Allergic asthma is characterized by airway hyperresponsiveness (AHR) and allergic inflammation of the airways, driven by allergen-specific Th2 cells. The asthma phenotypes and especially AHR are sensitive to the presence and activity of regulatory T (Treg) cells in the lung. Glucocorticoid-induced tumor necrosis factor receptor (GITR) is known to have a co-stimulatory function on effector CD4<sup>+ </sup>T cells, rendering these cells insensitive to Treg suppression. However, the effects of GITR signaling on polarized Th1 and Th2 cell effector functions are not well-established. We sought to evaluate the effect of GITR signaling on fully differentiated Th1 and Th2 cells and to determine the effects of GITR activation at the time of allergen provocation on AHR and airway inflammation in a Th2-driven mouse model of asthma.</p> <p>Methods</p> <p>CD4<sup>+</sup>CD25<sup>- </sup>cells were polarized <it>in vitro </it>into Th1 and Th2 effector cells, and re-stimulated in the presence of GITR agonistic antibodies to assess the effect on IFNÎł and IL-4 production. To evaluate the effects of GITR stimulation on AHR and allergic inflammation in a mouse asthma model, BALB/c mice were sensitized to OVA followed by airway challenges in the presence or absence of GITR agonist antibodies.</p> <p>Results</p> <p>GITR engagement potentiated cytokine release from CD3/CD28-stimulated Th2 but not Th1 cells <it>in vitro</it>. In the mouse asthma model, GITR triggering at the time of challenge induced enhanced airway hyperresponsiveness, serum IgE and <it>ex vivo </it>Th2 cytokine release, but did not increase BAL eosinophilia.</p> <p>Conclusion</p> <p>GITR exerts a differential effect on cytokine release of fully differentiated Th1 and Th2 cells <it>in vitro</it>, potentiating Th2 but not Th1 cytokine production. This effect on Th2 effector functions was also observed <it>in vivo </it>in our mouse model of asthma, resulting in enhanced AHR, serum IgE responses and Th2 cytokine production. This is the first report showing the effects of GITR activation on cytokine production by polarized primary Th1 and Th2 populations and the relevance of this pathway for AHR in mouse models for asthma. Our data provides crucial information on the mode of action of the GITR signaling, a pathway which is currently being considered for therapeutic intervention.</p

    Prostaglandin I2 Signaling Drives Th17 Differentiation and Exacerbates Experimental Autoimmune Encephalomyelitis

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    BACKGROUND: Prostaglandin I(2) (PGI(2)), a lipid mediator currently used in treatment of human disease, is a critical regulator of adaptive immune responses. Although PGI(2) signaling suppressed Th1 and Th2 immune responses, the role of PGI(2) in Th17 differentiation is not known. METHODOLOGY/PRINCIPAL FINDINGS: In mouse CD4(+)CD62L(+) naĂŻve T cell culture, the PGI(2) analogs iloprost and cicaprost increased IL-17A and IL-22 protein production and Th17 differentiation in vitro. This effect was augmented by IL-23 and was dependent on PGI(2) receptor IP signaling. In mouse bone marrow-derived CD11c(+) dendritic cells (BMDCs), PGI(2) analogs increased the ratio of IL-23/IL-12, which is correlated with increased ability of BMDCs to stimulate naĂŻve T cells for IL-17A production. Moreover, IP knockout mice had delayed onset of a Th17-associated neurological disease, experimental autoimmune encephalomyelitis (EAE), and reduced infiltration of IL-17A-expressing mononuclear cells in the spinal cords compared to wild type mice. These results suggest that PGI(2) promotes in vivo Th17 responses. CONCLUSION: The preferential stimulation of Th17 differentiation by IP signaling may have important clinical implications as PGI(2) and its analogs are commonly used to treat human pulmonary hypertension

    Relationship between the anti-inflammatory properties of salmeterol/fluticasone and the expression of CD4+CD25+Foxp3+ regulatory T cells in COPD

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    <p>Abstract</p> <p>Background</p> <p>Salmeterol and fluticasone combination (SFC) has anti-inflammatory effects and improves clinical symptoms in patients with chronic obstructive pulmonary disease (COPD). However, the anti-inflammatory mechanism of SFC remains unclear. In this study, we investigated the inflammatory responses of COPD, as well as the relationship of the inflammatory factors with the levels of CD4<sup>+</sup>CD25<sup>+</sup>Foxp3<sup>+ </sup>regulatory T cells (Foxp3<sup>+</sup>Tregs) after SFC therapy.</p> <p>Methods</p> <p>Twenty-one patients with moderate or severe COPD received treatment with 50/500 Όg of SFC twice a day for 12 weeks. Before and after treatment, the patients were evaluated using the Modified Medical Research Council (MMRC) dyspnea scale and by conducting a 6-min walk test. The number of neutrophils, monocytes and lymphocytes in induced sputum were counted. Levels of cytokines, including pre-inflammatory IL-8, TNF-α, IL-17A and cytokine IL-10, in the sputum supernatant and peripheral blood were measured by ELISA. The proportion of Foxp3<sup>+</sup>Tregs in the total CD4<sup>+ </sup>T cell of the peripheral blood was determined by flow cytometry. The relationship between IL-17A levels and the percentage of Foxp3<sup>+</sup>Tregs was analyzed by statistical analysis.</p> <p>Results</p> <p>After treatment with SFC, the forced expiratory volume in 1 s as a percentage of predicted values (FEV1%) and the 6-min walk distance in the COPD patients significantly increased, while dyspnea scores decreased. The total number of cells, neutrophils, and the percentage of neutrophils in induced sputum reduced notably, while the proportion of monocytes was significantly increased. Levels of the inflammatory cytokines IL-8, TNF-α, and IL-17A in the sputum supernatant and in the blood were markedly lowered, while IL-10 levels were unchanged. The proportion of Foxp3<sup>+</sup>Tregs in the total CD4<sup>+</sup>T cell population in the peripheral blood was drastically higher than that before treatment. The level of IL-17A was negatively correlated with the proportion of Foxp3<sup>+</sup>Tregs in CD4<sup>+</sup>T cells.</p> <p>Conclusion</p> <p>SFC can reduce the levels of inflammatory factors and improve symptoms of COPD. The levels of inflammatory factors are associated with the variation of Foxp3<sup>+</sup>Tregs in COPD.</p> <p>Trial registration</p> <p>This study was registered with <url>http://www.chictr.org</url> (Chinese Clinical Trial Register) as follows: ChiCTR-TNC-10001270</p
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