Routing Protocols in Delay Tolerant Networks: Comparative and Empirical Analysis

Wireless Personal Communications - A Delay Tolerant Network (DTN) is a network capable of handling long delays and data loss efficiently in various challenged scenarios and environments. Owing to...     

Smart City Healthcare Cyber Physical System: Characteristics,Technologies and Challenges

Wireless Personal Communications - The recent pandemic has demanded a strong and smart healthcare system which can monitor the patients efficiently and handle the situation that arises from the...     

Bandwidth Improvement of Stub Loaded Compact Ultra-Wideband Microstrip Patch Antenna for C/X-Band Applications

Wireless Personal Communications - Authentication is a term very important for data communication security. We see many frauds due to authentication failure. The problem manifolds when...     

Cocaine Induces Cytoskeletal Changes in Cardiac Myocytes: Implications for Cardiac Morphology

Cocaine is one of the most widely abused illicit drugs worldwide and has long been recognised as an agent of cardiac dysfunction in numerous cases of drug overdose. Cocaine has previously been shown to up-regulate cytoskeletal rearrangements and morphological changes in numerous tissues; however, previous literature observes such changes primarily in clinical case reports and addiction studies. An investigation into the fundamental cytoskeletal parameters of migration, adhesion and proliferation were studied to determine the cytoskeletal and cytotoxic basis of cocaine in cardiac cells. Treatment of cardiac myocytes with cocaine increased cell migration and adhesion (p < 0.05), with no effect on cell proliferation, except with higher doses eliciting (1–10 μg/mL) its diminution and increase in cell death. Cocaine downregulated phosphorylation of cofilin, decreased expression of adhesion modulators (integrin-β3) and increased expression of ezirin within three hours of 1 μg/mL treatments. These functional responses were associated with changes in cellular morphology, including alterations in membrane stability and a stellate-like phenotype with less compaction between cells. Higher dose treatments of cocaine (5–10 μg/mL) were associated with significant cardiomyocyte cell death (p < 0.05) and loss of cellular architecture. These results highlight the importance of cocaine in mediating cardiomyocyte function and cytotoxicity associated with the possible loss of intercellular contacts required to maintain normal cell viability, with implications for cardiotoxicity relating to hypertrophy and fibrogenesis.     

An energy-efficient cloud system with novel dynamic resource allocation methods

The Journal of Supercomputing - In the last decade, cloud computing has brought enormous changes to people’s lives. Cloud computing gives a client-driven computational model. In this case,...     

Trans-differentiation of human adipose-derived mesenchymal stem cells into cardiomyocyte-like cells on decellularized bovine myocardial extracellular matrix-based films

In this study, we aimed at fabricating decellularized bovine myocardial extracellular matrix-based films (dMEbF) for cardiac tissue engineering (CTE). The decellularization process was carried out utilizing four consecutive stages including hypotonic treatment, detergent treatment, enzymatic digestion and decontamination, respectively. In order to fabricate the dMEbF, dBM were digested with pepsin and gelation process was conducted. dMEbF were then crosslinked with N-hydroxysuccinimide/1-Ethyl-3-(3-dimethylaminopropyl)-carbodiimide (NHS/EDC) to increase their durability. Nuclear contents of native BM and decellularized BM (dBM) tissues were determined with DNA content analysis and agarose-gel electrophoresis. Cell viability on dMEbF for 3rd, 7th, and 14th days was assessed by MTT assay. Cell attachment on dMEbF was also studied by scanning electron microscopy. Trans-differentiation capacity of human adipose-derived mesenchymal stem cells (hAMSCs) into cardiomyocyte-like cells on dMEbF were also evaluated by histochemical and immunohistochemical analyses. DNA contents for native and dBM were, respectively, found as 886.11?±?164.85 and 47.66?±?0.09?ng/mg dry weight, indicating a successful decellularization process. The results of glycosaminoglycan and hydroxyproline assay, and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), performed in order to characterize the extracellular matrix (ECM) composition of native and dBM tissue, showed that the BM matrix was not damaged during the proposed method. Lastly, regarding the histological study, dMEbF not only mimics native ECM, but also induces the stem cells into cardiomyocyte-like cells phenotype which brings it the potential of use in CTE.     

Thermodynamic performance analysis of three solid oxide fuel cell and gas microturbine hybrid systems for application in auxiliary power units

In this study, three different configurations of a solid oxide fuel cell and gas microturbine hybrid system are evaluated for application in auxiliary power units. The first configuration is a common hybrid system in auxiliary power units, utilizing a fuel cell stack in the structure of the gas turbine cycle. The other configurations use two series and parallel fuel cell stacks in the structure of the gas turbine cycle. The main purpose of this research is thermodynamic analysis, evaluation of the performance of the proposed hybrid systems in similar conditions, and selection of an appropriate system in terms of efficiency, power generation, and entropy generation rate. In this study, the utilized fuel cells were subjected to electrochemical, thermodynamic, and thermal analyses and their working temperatures were calculated under various working conditions. Results indicate that the hybrid system with two series stacks had maximum power generation and efficiency compared with the other two cases. Moreover, the simple hybrid system and the system with two parallel stacks had relatively equal pure power generation and efficiency. According to the investigations, hybrid system with two series fuel cell stacks, which had 3424 and 1712 cells, respectively, can achieve the electrical efficiency of over 48%. A hybrid system with two parallel fuel cell stacks, in which each stack had 2568 cells, had the electrical efficiency of 46.3%. Findings suggested that maximum electrical efficiency occurred between the pressure ratios of 5–6 in the proposed hybrid systems.     

Effect of sand and clay fouling on the shear strength of railway ballast for different ballast gradations

Ballast contamination by fine materials such as sand and clay in railway track at arid regions is an important issue that causes track instability problems and settlement due to reduction of shear strength of ballast. In this paper, the results of direct shear box test conducted on clean ballast, sand-fouled ballast and clay-fouled ballast for different ballast gradations are reported and discussed. For this purpose, three different fouling amounts according to fouling index are added to clean ballast. Test results show that by increasing the fouling percentage, the ballast shear strength always decreases both for sand and clay fouled ballast. However, the amount of shear strength reduction is low at high normal stresses. Clay contamination has more adverse effect on the shear strength of ballast compared with sand contamination. Also, the results of tests for evaluation of gradation effect on shear strength of fouled ballast which are conducted on various gradations according to American Railway Engineering and Maintenance-of-Way Association, show that the maximum particle size as well as uniformity coefficient affect the shear strength of ballast. Also, an empirical equation is presented to observe the effect of ballast gradation on reduction of shear strength with regard to amount of fouling material and normal stress.     

Pressure Management in Water Distribution Systems Using a Self-Tuning Controller to Distribute the Available Potable Water with Equality

The rapid population growth of cities in developing countries (DC) make difficult to distribute the available potable water (PW) with equality. The distribution problem arises from an insufficient amount of PW and because cities water distribution systems (WDS) are not efficient. The novelty of this paper is a self-tuning controller (STC) proposed to manage, along the day, the pressure of water through the nodes of a WDS. It means, pressure management (PM) is proposed to control water levels (WLs) in householders tanks (HTs). The objective is to satisfy with equality the PW demand at different zones of a city forcing the flow of water by managing the pressure. The proposed STC performance is tested on the digital simulator developed to characterize the hydraulic operation of a WDS. The dynamic behaviour of the WDS is determined by the variation of the WL in the tanks of the WDS when water is supplied or extracted from them. The WDS of Mexico City is analysed and the proposed STC is applied to a simplified WDS. The results allow to conclude that the proposed STC could become a supporting tool for the decision making of WDS operators.