181 research outputs found

    SECURED DATA AGGREGATION METHODS IN WIRELESS SENSOR NETWORKS USING HOMOMORPHIC OPERATION - A REVIEW

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    Wireless sensor networks are energy constrained. Data aggregation is an important mechanism for achieving energy efficiency in such networks. The aggregation reduces redundancy in data transmission which results in improved energy usage. Several security issues are there in data aggregation, which includes data confidentiality, data integrity, availability, and freshness. Such issues become complex since WSN is deployed in hostile and unattended environment. So the sensor nodes may fail and compromised by adversaries. Secured data aggregation in sensor network is a topic of research.  Many solutions are proposed for secured data aggregation, using different encryption methods. Homomorphic encryption is one of such technique. In homomorphic encryption, all the nodes participate in the aggregation. Here, nodes can't see any intermediate or final result but the aggregation is efficient. In this paper, secured data aggregation methods are classified and the performance is compared in terms of integrity and confidentiality

    Understanding DNA based Nanostructures

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    We use molecular dynamics (MD) simulations to understand the structure, and stability of various Paranemic crossover (PX) DNA molecules and their topoisomer JX molecules, synthesized recently by Seeman and coworkers at New York University (NYU). Our studies include all atoms (4432 to 6215) of the PX structures with an explicit description of solvent and ions (for a total of up to 42,000 atoms) with periodic boundary conditions. We report the effect of divalent counterions Mg(+2) on the structural and thermodynamic properties of these molecules and compare them to our previously reported results in presence of monovalent Na+ ions. The dynamic structures averaged over the 3-nanosecond simulations preserves the Watson-Crick hydrogen bonding as well as the helical structure. We find that PX65 is the most stable structure both in Na+ and Mg(+2) in accordance with the experimental results. PX65 has helical twist and other helical structural parameters close to the values for normal B-DNA of similar length and sequence. Our strain energy calculations demonstrate that stability of the crossover structure increases with the increase in crossover points

    FACTORS INFLUENCING JOB REJECTIONS IN CLOUD ENVIRONMENT

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    The IT organizations invests heavy capital by consuming large scale infrastructure and advanced operating platforms. The advances in technology has resulted in emergence of cloud computing, which is promising technology to achieve the aforementioned objective. At the peak hours, the jobs arriving to the cloud system are normally high demanding efficient execution and dispatch. An observation that has been carried out in this paper by capturing a job arriving pattern from a monitoring system explains that most of the jobs get rejected because of lack of efficient technology. The job rejections can be controlled by certain factors such as job scheduling and load balancing. Therefore, in this paper the efficiency of Round Robin (RR) scheduling strategy used for job scheduling and Shortest Job First Scheduling (SJFS) technique used for load balancing in reducing the job rejections are analyzed. Further, a proposal for an effective load balancing approach to avoid deadlocks has been discussed

    Role of Specific Cations and Water Entropy on the Stability of Branched DNA Motif Structures

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    DNA three-way junctions (TWJs) are important intermediates in various cellular processes and are the simplest of a family of branched nucleic acids being considered as scaffolds for biomolecular nanotechnology. Branched nucleic acids are stabilized by divalent cations such as Mg^2+, presumably due to condensation and neutralization of the negatively charged DNA backbone. However, electrostatic screening effects point to more complex solvation dynamics and a large role of interfacial waters in thermodynamic stability. Here, we report extensive computer simulations in explicit water and salt on a model TWJ and use free energy calculations to quantify the role of ionic character and strength on stability. We find that enthalpic stabilization of the first and second hydration shells by Mg^2+ accounts for 1/3 and all of the free energy gain in 50% and pure MgCl_2 solutions, respectively. The more distorted DNA molecule is actually destabilized in pure MgCl_2 compared to pure NaCl. Notably, the first shell, interfacial waters have very low translational and rotational entropy (i.e., mobility) compared to the bulk, an entropic loss that is overcompensated by increased enthalpy from additional electrostatic interactions with Mg^2+. In contrast, the second hydration shell has anomalously high entropy as it is trapped between an immobile and bulklike layer. The nonmonotonic entropic signature and long-range perturbations of the hydration shells to Mg^2+ may have implications in the molecular recognition of these motifs. For example, we find that low salt stabilizes the parallel configuration of the three-way junction, whereas at normal salt we find antiparallel configurations deduced from the NMR. We use the 2PT analysis to follow the thermodynamics of this transition and find that the free energy barrier is dominated by entropic effects that result from the decreased surface area of the antiparallel form which has a smaller number of low entropy waters in the first monolayer

    Farmakokinetika u plazmi i režim doziranja cefpirom-sulfata u ovaca

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    Cefpirome is fourth- generation cephalosporin class of drug with a broad spectrum of activity against Gram- positive and Gram- negative organisms. A pharmacokinetic study of single dose intravenous (IV) and intramuscular (IM) administration of cefpirome sulfate (10 mg/kg body weight) was conducted using High Performance Liquid Chromatography (HPLC) and the pharmacokinetic parameters established were utilized to calculate optimal dosage regimens in ewes. Following IV administration of cefpirome in ewes the mean value of the elimination rate constant (β), elimination half life (t½β), the area under the plasma drug concentration-time curve (AUC0-∞), the area under the first moment of the plasma drug concentration (AUMC), the mean residence time (MRT), the apparent volume of distribution (Vdarea) and total body clearance (ClB) were 0.43 ± 0.04 h-1, 1.68 ± 0.21 h, 82.71 ± 3.76 mg.h/mL, 211.06 ± 23.99 mg.h2/mL, 2.51 ± 0.19 h, 0.28 ± 0.03 L/kg and 0.11 ± 0.00 L/h/kg, respectively, while following IM administration of cefpirome the mean values were 0.33 ± 0.01 h-1, 2.04 ± 0.06 h, 73.27 ± 4.04 mg.h/mL, 229.02 ± 20.32 mg.h2/mL, 3.09 ± 0.12 h, 0.45 ± 0.03 L/kg and 0.14 ± 0.01 L/h/kg, respectively. The bioavailability following IM administration of cefpirome was 88.85 ± 4.07 %. Cefpirome concentration in plasma was maintained above the target MIC (≥0.25 mg/mL) for 12 h. The therapeutic dosage regimen calculated using the pharmacokinetic parameters generated by the intravenous route of drug administration indicated the most appropriate dose of cefpirome to maintain MIC at ≥ 0.25 μg/mL with a dosage interval of 12 h, would be 13.00 mg/kg body weight in ewes.Cefpirom je cefalosporin četvrte generacije lijekova sa širokim spektrom djelovanja protiv gram-pozitivnih i gram-negativnih mikroorganizama. Istraživanje farmakokinetike pojedinačne doze cefpirom-sulfata, primijenjene intravenski (iv.) i intramuskularno (im.) (10 mg/kg tjelesne mase), provedeno je tekućinskom kromatografijom visoke djelotvornosti (HPLC) te su utvrđeni pokazatelji za optimalan režim doziranja u ovaca. Nakon intravenske primjene cefpiroma u ovaca prosječna vrijednost konstante brzine eliminacije (β) bila je 0,43 ± 0,04 h-1, poluvijek eliminacije (t½β) 1,68 ± 0,21 h, područje ispod krivulje odnosa koncentracije u plazmi i vremena (AUC0-∞) 82,71 ± 3,76 mg.h/ mL, područje ispod krivulje prvog momenta koncentracije u plazmi (AUMC) 211,06 ± 23,99 mg.h2/mL. Nadalje, srednja vrijednost vremena zadržavanja (MRT) bila je 2,51 ± 0,19 h, prividni volumen distribucije (Vdarea) 0,28 ± 0,03 L/kg i ukupni tjelesni klirens (ClB) 0,11 ± 0,00 L/h/kg. Srednje vrijednosti tijekom intramuskularne primjene cefpiroma za prethodno navedene parametre bile 0,33 ± 0,01 h-1, 2,04 ± 0,06 h, 73,27 ± 4,04 mg.h/mL, 229,02 ± 20,32 mg.h2/mL, 3,09 ± 0,12 h, 0,45 ± 0,03 L/kg i 0,14 ± 0,01 L/h/kg. Bioraspoloživost nakon intramuskularne primjene cefpiroma bila je 88,85 ± 4,07 %. Koncentracija cefpiroma u plazmi održavana je iznad ciljne vrijednosti MIK-a (≥ 0,25 mg/mL) tijekom 12 sati. Terapijski režim doziranja izračunat na temelju farmakokinetičkih pokazatelja dobivenih intravenskom primjenom lijeka upućuje na optimalnu dozu cefpiroma kojom se može održati MIK pri vrijednosti ≥ 0,25 μg/mL s intervalom doziranja od 12 sati, a ta bi doza u ovaca bila 13,00 mg/kg tjelesne mase

    Indolent Small Intestinal CD4+ T-cell Lymphoma Is a Distinct Entity with Unique Biologic and Clinical Features

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    Enteropathy-associated T-cell lymphomas (EATL) are rare and generally aggressive types of peripheral T-cell lymphomas. Rare cases of primary, small intestinal CD4+ T-cell lymphomas with indolent behavior have been described, but are not well characterized. We describe morphologic, phenotypic, genomic and clinical features of 3 cases of indolent primary small intestinal CD4+ T-cell lymphomas. All patients presented with diarrhea and weight loss and were diagnosed with celiac disease refractory to a gluten free diet at referring institutions. Small intestinal biopsies showed crypt hyperplasia, villous atrophy and a dense lamina propria infiltrate of small-sized CD4+ T-cells often with CD7 downregulation or loss. Gastric and colonic involvement was also detected (n = 2 each). Persistent, clonal TCRβ gene rearrangement products were detected at multiple sites. SNP array analysis showed relative genomic stability, early in disease course, and non-recurrent genetic abnormalities, but complex changes were seen at disease transformation (n = 1). Two patients are alive with persistent disease (4.6 and 2.5 years post-diagnosis), despite immunomodulatory therapy; one died due to bowel perforation related to large cell transformation 11 years post-diagnosis. Unique pathobiologic features warrant designation of indolent small intestinal CD4+ T-cell lymphoma as a distinct entity, greater awareness of which would avoid misdiagnosis as EATL or an inflammatory disorder, especially celiac disease
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