150 research outputs found

    Minimum traffic inter-BS SHO boundary selection algorithm for CDMA-based wireless networks

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    An algorithm is presented to select an inter-base station soft handoff (inter-BS SHO) boundary for code division multiple access (CDMA)-based wireless networks. The selected inter-BS SHO boundary splits base transceiver systems (BTSs) equally over two BSs, and reduces the amount of links needed to support inter-BS SHO by minimizing the amount of traffic flow crossing the boundary. The algorithm has an O(n/sup 4/) running time, where n is the number of BTSs in the wireless network

    Minimum traffic inter-BS SHO boundary selection algorithm for CDMA-based wireless networks

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    An algorithm is presented to select an inter-base station soft handoff (inter-BS SHO) boundary for code division multiple access (CDMA)-based wireless networks. The selected inter-BS SHO boundary splits base transceiver systems (BTSs) equally over two BSs, and reduces the amount of links needed to support inter-BS SHO by minimizing the amount of traffic flow crossing the boundary. The algorithm has an O(n/sup 4/) running time, where n is the number of BTSs in the wireless network

    The role of nitric oxide in hindlimb remote ischaemic preconditioning of the liver

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    Ischaemia reperfusion (IR) injury is a major contributor to morbidity and mortality following liver resection and transplantation. Hindlimb remote ischaemic preconditioning (RIPC) reduces liver IR injury but the mechanisms underlying this protection are unknown. This thesis evaluated the effects of RIPC on the early phase of liver IR injury in a new mouse model. This model was used to assess the role of the nitric oxide (NO) pathway in mediating the protective effects of RIPC on liver IR injury. In the initial experiments wild type C57BL/6 mice were used to establish a new model of hindlimb RIPC that protects against liver IR injury. The new experimental model hindlimb protocol consisted of 6 cycles of 4 minutes of femoral vessel clamping followed by 4 minutes of reperfusion. The IR protocol consisted of a well-described 40 minutes of lobar liver (70%) ischaemia followed by 2 hours reperfusion. This hindlimb RIPC model resulted in significant reductions in liver IR injury, as evaluated by plasma liver transaminases levels, histopathological scores, and ultrastructural assessment of cellular damage in the liver. In addition hindlimb RIPC preserved the hepatic microcirculatory blood flow (MBF) in livers subjected to IR. In subsequent experiments administration of the selective NO scavenger C-PTIO to wild type mice abrogated the protective effects of limb RIPC on liver IR injury. In addition the RIPC-induced preservation of hepatic MBF was attenuated by C-PTIO administration. In contrast to the protective effects of limb RIPC on liver IR injury in wild type mice; mice lacking the constitutively expressed NO synthase (eNOS-/-) enzyme were not protected against liver IR injury by hindlimb RIPC, and MBF measurements in these mice showed no benefit of RIPC on the microcirculation. In wild type mice hepatic and limb eNOS protein expression was similar among preconditioned and non-preconditioned animals. In comparison expression of the inducible NOS (iNOS) isoform was only seen in preconditioned animals. In order to elicit the pathway through which RIPC-derived NO protects against liver IR injury, plasma nitrite and nitrate (NOx) levels were quantified in wild type animals and shown to be significantly elevated in preconditioned compared to non-preconditioned animals. However, intravenous administration of exogenous nitrite to eNOS-/- mice undergoing liver IR injury failed to mimic the protective effects of RIPC-derived endogenous NOx in wild types. Administration of the soluble guanylyl cyclase (sGC) inhibitor ODQ showed a trend indicating reversal of the protective effects of RIPC on liver IR injury but this did not reach statistical significance. ODQ significantly annulled the protective effects of limb RIPC on hepatic MBF during liver reperfusion. Measurement of hepatic cyclic GMP levels in wild type animals showed a significant increase in animals subjected to limb RIPC only compared to sham. However there was no difference in the cGMP levels in the RIPC + IR compared to the IR group. In conclusion this thesis has described a new mouse model of limb RIPC that protects against liver IR injury. It was also shown that NO and eNOS are essential in mediating the protective effects of limb RIPC on liver IR injury. Endogenous NOx metabolites of NO play a crucial role in RIPC induced protection. The hepatic sGCcGMP pathway is at least partially involved in RIPC-induced liver protection

    Prediction of Critical Flashover Voltage of High Voltage Insulators Leveraging Bootstrap Neural Network

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    Understanding the flashover performance of the outdoor high voltage insulator has been in the interest of many researchers recently. Various studies have been performed to investigate the critical flashover voltage of outdoor high voltage insulators analytically and in the laboratory. However, laboratory experiments are expensive and time-consuming. On the other hand, mathematical models are based on certain assumptions which compromise on the accuracy of results. This paper presents an intelligent system based on Artificial Neural Networks (ANN) to predict the critical flashover voltage of High-Temperature Vulcanized (HTV) silicone rubber in polluted and humid conditions. Various types of learning algorithms are used, such as Gradient Descent (GD), Levenberg-Marquardt (LM), Conjugate Gradient (CG), Quasi-Newton (QN), Resilient Backpropagation (RBP), and Bayesian Regularization Backpropagation (BRBP) to train the ANN. The number of neurons in the hidden layers along with the learning rate was varied to understand the effect of these parameters on the performance of ANN. The proposed ANN was trained using experimental data obtained from extensive experimentation in the laboratory under controlled environmental conditions. The proposed model demonstrates promising results and can be used to monitor outdoor high voltage insulators. It was observed from obtained results that changing of the number of neurons, learning rates, and learning algorithms of ANN significantly change the performance of the proposed algorithm

    Improving Project Logistics by using IoT

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    This BachelorŽs thesis is made on behalf of WÀrtsilÀ Energy Solutions, Project Logistics & Transport Management department whose main task is to coordinate and ensure that materials and products are transported to the right place and on time in Project Logistics. This thesis examines how you could improve WÀrtsilÀŽs Project Logistics by using Internet of Things. By developing IoT, there has been an increased chance to get more information about transports than before and WÀrtsilÀ is currently looking for new solutions to use that could improve their current logistics system. The purpose of this thesis is to review new, and used, solutions on the market, and then see what could work in practice at WÀrtsilÀ. Material to this thesis are gathered from books, web pages and articles that reviewed interesting IoT solutions and which also gave examples on different solutions that are used by other companies in the same business. The Result is two different methods that could improve WÀrtsilÀŽs Project Logistics in different occasions. These results are intended to give tips on how IoT could improve the departmentŽs ways of coordinating and check transports and logistics within a project.Detta examensarbete Àr gjort i uppdrag av WÀrtsilÀ Energy Solutions, Project logistics & Transport Management avdelningen vars huvuduppgift Àr att koordinera och se till att material och produkter transporteras till rÀtt plats i rÀtt tid inom projekt logistiken. Examensarbetet behandlar hur man kunde förbÀttra WÀrtsilÀs projekt logistik genom att anvÀnda Internet of Things. Genom att IoT har utvecklats har det uppstÄtt möjligheter att fÄ fram mer information om transporter Àn tidigare och WÀrtsilÀ söker för tillfÀllet nya lösningar som kunde anvÀndas för att förbÀttra deras nuvarande logistiksystem. Syftet med arbetet Àr att gÄ igenom nya, men Àven redan befintliga, lösningar som anvÀnds pÄ dagens marknad - för att sedan se vad som kunde fungera i praktiken hos WÀrtsilÀ. Material till arbetet Àr samlat frÄn böcker, webbsidor och artiklar som gick igenom intressanta IoT lösningar och som ocksÄ gav exempel pÄ hur olika system fungerar och anvÀnds av andra företag inom samma bransch. Slutresultatet blev tvÄ olika metoder som kunde förbÀttra WÀrtsilÀs projekt logistik vid olika tillfÀllen. Dessa resultat Àr tÀnkta för att ge tips pÄ hur IoT kunde förbÀttra avdelningens sÀtt hur man koordinerar och granskar transporter och logistiken inom ett projekt

    Oxidation of HMGB1 Causes Attenuation of Its Pro-Inflammatory Activity and Occurs during Liver Ischemia and Reperfusion

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    High mobility group box 1 (HMGB1) is a nuclear transcription factor. Once HMGB1 is released by damaged cells or activated immune cells, it acts as danger molecule and triggers the inflammatory signaling cascade. Currently, evidence is accumulating that posttranslational modifications such as oxidation may modulate the pro-inflammatory potential of danger signals. We hypothesized that oxidation of HMGB1 may reduce its pro-inflammatory potential and could take place during prolonged ischemia and upon reperfusion

    Identification of Novel Pro-Migratory, Cancer-Associated Genes Using Quantitative, Microscopy-Based Screening

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    Background: Cell migration is a highly complex process, regulated by multiple genes, signaling pathways and external stimuli. To discover genes or pharmacological agents that can modulate the migratory activity of cells, screening strategies that enable the monitoring of diverse migratory parameters in a large number of samples are necessary. Methodology: In the present study, we describe the development of a quantitative, high-throughput cell migration assay, based on a modified phagokinetic tracks (PKT) procedure, and apply it for identifying novel pro-migratory genes in a cancer-related gene library. In brief, cells are seeded on fibronectin-coated 96-well plates, covered with a monolayer of carboxylated latex beads. Motile cells clear the beads, located along their migratory paths, forming tracks that are visualized using an automated, transmitted-light screening microscope. The tracks are then segmented and characterized by multi-parametric, morphometric analysis, resolving a variety of morphological and kinetic features. Conclusions: In this screen we identified 4 novel genes derived from breast carcinoma related cDNA library, whose over-expression induces major alteration in the migration of the stationary MCF7 cells. This approach can serve for high throughput screening for novel ways to modulate cellular migration in pathological states such as tumor metastasis and invasion

    Remote ischemic conditioning: from experimental observation to clinical application: report from the 8th Biennial Hatter Cardiovascular Institute Workshop

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    In 1993, Przyklenk and colleagues made the intriguing experimental observation that 'brief ischemia in one vascular bed also protects remote, virgin myocardium from subsequent sustained coronary artery occlusion' and that this effect '.... may be mediated by factor(s) activated, produced, or transported throughout the heart during brief ischemia/reperfusion'. This seminal study laid the foundation for the discovery of 'remote ischemic conditioning' (RIC), a phenomenon in which the heart is protected from the detrimental effects of acute ischemia/reperfusion injury (IRI), by applying cycles of brief ischemia and reperfusion to an organ or tissue remote from the heart. The concept of RIC quickly evolved to extend beyond the heart, encompassing inter-organ protection against acute IRI. The crucial discovery that the protective RIC stimulus could be applied non-invasively, by simply inflating and deflating a blood pressure cuff placed on the upper arm to induce cycles of brief ischemia and reperfusion, has facilitated the translation of RIC into the clinical setting. Despite intensive investigation over the last 20 years, the underlying mechanisms continue to elude researchers. In the 8th Biennial Hatter Cardiovascular Institute Workshop, recent developments in the field of RIC were discussed with a focus on new insights into the underlying mechanisms, the diversity of non-cardiac protection, new clinical applications, and large outcome studies. The scientific advances made in this field of research highlight the journey that RIC has made from being an intriguing experimental observation to a clinical application with patient benefit
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