125 research outputs found

    Density Functional Theory; A New Route for Structural and Thermodynamic Parameters Calculations

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    Structural and thermodynamic parameters of the studied virgin polymeric matrices poly e-caprolactone (PCL), Chitosan (Chi) and their polymer blend were investigated using theoretical density functional theory (DFT). Thermodynamic functions were calculated based on vibrational frequencies and optimized geometrical coordinates in the temperature range 25-1000 °K which cannot be amended easily. Calculated free energy was found to be convex in terms of extensive variable and concave in terms of intensive ones

    Modified Dijkstra Shortest Path Algorithm for SD Networks

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    This paper uses a modified Dijkstra shortest path method for considering cumulative delays rather than bandwidth in software-defined networks. To implement the proposed method, an open-source Ryu controller is used, and a Mininet tool is used to emulate the topology. The proposed method is compared with the traditional Dijkstra’s algorithm to demonstrate its performance. This comparison shows that the modified Dijkstra’s algorithm provides higher performance of the different cumulative delays. Several experiments were conducted to evaluate the performance of the proposed method using three parameters (bandwidth, transfer rate and jitter). In addition, the cumulative distribution function is calculated using the parameters to show its distribution through the experiment period

    A model for integrating home-work tour scheduling with time-varying network congestion and marginal utility profiles for home and work activities.

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    The existing literature on activity-based modeling emphasizes that individuals schedule their activities by keeping the whole-day activity pattern in mind. Several attempts have been made to integrate this with network congestion; however, for explicit explanation of travel behavior of individuals, further improvements are required. The proposed model is a combined model that addresses the scheduling of the home-work tour with time-varied network congestion in a fixed-point problem frame-work. Marginal utility profiles that represent individual time-of-day preferences and satiation effect of the activities are incorporated for the measurement of the utility of activity engagement along with the disutility of travel. Consideration of only time-of-day dependent marginal utility profiles of activities in the utility function does not appropriately integrate activities and travel within the tour. The proof is shown analytically and numerically. This finding contradicts earlier research into integration of morning and evening commutes with network congestion. Additionally, the results of two numerical experiments are presented. In the first experiment, an arbitrary dynamic tolling strategy is assumed, and then a detailed analysis is performed to show variation in the balance of trade-offs involved in the process. The second experiment assesses the sensitivity of the combined model through incorporation of different dynamic traffic loading models. Some meaningful observations are drawn from these experiments and are discussed with the identification of avenues for future research

    Basin Analysis of the Late Cretaceous Sediments in United Arab Emirates

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    Abstract: The Late Cretaceous Simsima Formation has been proved to be one of the most prolific reservoirs in the Arabian Basin, but still needs more investigations to be ultimately exploited.This promising formation has been subjected to a comprehensive study by various geologic disciplines to build up an adequate basin model for such formation. The study revealed that the Late Cretaceous Simsima Formation could be classified into two facies. These are Planktonic Foraminiferal Biomicrite (open marine source rock facies outcropped at Jabal Qarn El-Barr); and Rudistids Algal Foraminiferal Biomicrite (shallow marine reservoir rock facies exposed at Jabal Buhays and Jabal Malaqet) facies. This facies distribution indicates that the Late Cretaceous sea deepened towards the NNW of UAE ( Jabal Qarn El-Barr section). X-Ray diffraction analysis ensured the occurrence of open marine minerals (kaolinite and montmorillonite) within the Late Cretaceous Simsima Formation that outcropped at Jabal Qarn El-Barr. So, the Late Cretaceous Simsima Formation could act as an effective source rock (newly approved) in the northern part of UAE and a prolific reservoir rock in the other parts of UAE. The geochemical analyses also supported the occurrence of source rock facies (high TOC varies from 0.4 to 1.3 wt% and low Pr/Ph ratio) within the Late Cretaceous Simsima Formation. The petrophysical and petrographical investigations proved intercrystalline, vuggy and fracture porosity (varies from 0 to 31%) and permeability ranges from 0 to 850 md for the reservoir facies of Late Cretaceous Simsima Formation. Moreover, the occurrence of anticlinal and thrusted structures (almost acting as sealing faults) within the fractured limestones of the Late Cretaceous Simsima Formation would enhance the probability for hydrocarbon entrapment within these rocks

    NUDT2 Disruption Elevates Diadenosine Tetraphosphate (Ap4A) and Down-Regulates Immune Response and Cancer Promotion Genes.

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    Regulation of gene expression is one of several roles proposed for the stress-induced nucleotide diadenosine tetraphosphate (Ap4A). We have examined this directly by a comparative RNA-Seq analysis of KBM-7 chronic myelogenous leukemia cells and KBM-7 cells in which the NUDT2 Ap4A hydrolase gene had been disrupted (NuKO cells), causing a 175-fold increase in intracellular Ap4A. 6,288 differentially expressed genes were identified with P < 0.05. Of these, 980 were up-regulated and 705 down-regulated in NuKO cells with a fold-change ≥ 2. Ingenuity® Pathway Analysis (IPA®) was used to assign these genes to known canonical pathways and functional networks. Pathways associated with interferon responses, pattern recognition receptors and inflammation scored highly in the down-regulated set of genes while functions associated with MHC class II antigens were prominent among the up-regulated genes, which otherwise showed little organization into major functional gene sets. Tryptophan catabolism was also strongly down-regulated as were numerous genes known to be involved in tumor promotion in other systems, with roles in the epithelial-mesenchymal transition, proliferation, invasion and metastasis. Conversely, some pro-apoptotic genes were up-regulated. Major upstream factors predicted by IPA® for gene down-regulation included NFκB, STAT1/2, IRF3/4 and SP1 but no major factors controlling gene up-regulation were identified. Potential mechanisms for gene regulation mediated by Ap4A and/or NUDT2 disruption include binding of Ap4A to the HINT1 co-repressor, autocrine activation of purinoceptors by Ap4A, chromatin remodeling, effects of NUDT2 loss on transcript stability, and inhibition of ATP-dependent regulatory factors such as protein kinases by Ap4A. Existing evidence favors the last of these as the most probable mechanism. Regardless, our results suggest that the NUDT2 protein could be a novel cancer chemotherapeutic target, with its inhibition potentially exerting strong anti-tumor effects via multiple pathways involving metastasis, invasion, immunosuppression and apoptosis

    Global economic burden of unmet surgical need for appendicitis

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    Background: There is a substantial gap in provision of adequate surgical care in many low-and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods: Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capital approach was applied, focusing on the economic burden resulting from premature death and absenteeism. Results: Excess mortality was 4185 per 100 000 cases of appendicitis using approach 1 and 3448 per 100 000 using approach 2. The economic burden of continuing current levels of access and local quality was US 92492millionusingapproach1and92 492 million using approach 1 and 73 141 million using approach 2. The economic burden of not providing surgical care to the standards of high-income countries was 95004millionusingapproach1and95 004 million using approach 1 and 75 666 million using approach 2. The largest share of these costs resulted from premature death (97.7 per cent) and lack of access (97.0 per cent) in contrast to lack of quality. Conclusion: For a comparatively non-complex emergency condition such as appendicitis, increasing access to care should be prioritized. Although improving quality of care should not be neglected, increasing provision of care at current standards could reduce societal costs substantially
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