2,335 research outputs found

    Running of the Spectral index in Deformed Matter Bounce Scenarios with Hubble-rate-dependent Dark Energy

    Full text link
    As a deformed matter bounce scenario with a dark energy component we propose a deformed one with running vacuum model (RVM) in which the dark energy density is written as a power series of H2H^2 and HĖ™\dot H with a constant equation of state parameter same as the cosmological constant. Our results in analytical and numerical point of views show that in some cases same as LCDM bounce scenario, although the spectral index may achieve a good consistency with observations, a positive value of running of spectral index is obtained which is not compatible with inflationary paradigm where it predicts a small negative value for Ī±s\alpha_s. However, by extending the power series up to H4H^4, ĻĪ›=n0+n2H2+n4H4\rho_{\Lambda}=n_0+n_2 H^2+n_4 H^4, and estimating a set of consistent parameters, we obtain the spectral index nsn_s, a small negative value of running Ī±s\alpha_s and tensor to scalar ratio rr, which these reval a degeneracy between deformed matter bounce scenario with RVM-DE and inflationary cosmology.Comment: 27 pages, 6 figure

    Heart surgery waiting time: Assessing the effectiveness of an action

    Get PDF
    Background: Waiting time is an index assessing patient satisfaction, managerial effectiveness and horizontal equity in providing health care. Although heart surgery centers establishment is attractive for politicians. They are always faced with the question of to what extent they solve patientā€™s problems. Objectives: The objective of this study was to evaluate factors influencing waiting time in patients of heart surgery centers, and to make recommendations for health-care policy-makers for reducing waiting time and increasing the quality of services from this perspective. Patients and Methods: This cross-sectional study was performed in 2013. After searching articles on PubMed, Elsevier, Google Scholar, Ovid, Magiran, IranMedex, and SID, a list of several criteria, which relate to waiting time, was provided. Afterwards, the data on waiting time were collected by a researcher-structured checklist from 156 hospitalized patients. The data were analyzed by SPSS 16. The Kolmogorov Smirnov and Shapiro tests were used for determination of normality. Due to the non-normal distribution, non-parametric tests, such as Kruskal-Wallis and Mann-Whitney were chosen for reporting significance. Parametric tests also used reporting medians. Results: Among the studied variables, just economic status had a significant relation with waiting time (P = 0.37). Fifty percent of participants had diabetes, whereas this estimate was 43.58% for high blood pressure. As the cause of delay, 28.2% of patients reported financial problems, 18.6% personal problem and 13.5% a delay in providing equipment by the hospital. Conclusions: It seems the studied hospital should review its waiting time arrangements and detach them, as far as possible, from subjective and personal (specialists) decisions. On the other hand, ministries of health and insurance companies should consider more financial support. It is also recommend that hospitals should arrange preoperational psychiatric consultation for increasing patientsā€™ emotionally readiness. Ā© 2015, Iranian Red Crescent Medical Journal

    Turbulence kinetic energy equation for dilute suspensions

    Get PDF
    A multiphase turbulence closure model is presented which employs one transport equation, namely the turbulence kinetic energy equation. The proposed form of this equation is different from the earlier formulations in some aspects. The power spectrum of the carrier fluid is divided into two regions, which interact in different ways and at different rates with the suspended particles as a function of the particle-eddy size ratio and density ratio. The length scale is described algebraically. A mass/time averaging procedure for the momentum and kinetic energy equations is adopted. The resulting turbulence correlations are modeled under less retrictive assumptions comparative to previous work. The closures for the momentum and kinetic energy equations are given. Comparisons of the predictions with experimental results on liquid-solid jet and gas-solid pipe flow show satisfactory agreement

    Identification and pharmacological inactivation of the MYCN gene network as a therapeutic strategy for neuroblastic tumor cells

    Get PDF
    This research was originally published in Journal of Biological Chemistry. Olesya Chayka, Cosimo Walter Dā€™Acunto, Odette Middleton, Maryam Arab, and Arturo Sala. Identification and Pharmacological Inactivation of the MYCN Gene Network as a Therapeutic Strategy for Neuroblastic Tumor Cells. Journal of Biological Chemistry. 2015; Vol 290 (4) :pp. 2198 - 2212. Ā© the American Society for Biochemistry and Molecular Biology.This article has been made available through the Brunel Open Access Publishing Fund.The MYC family of transcription factors consists of three well characterized members, c-MYC, L-MYC, and MYCN, deregulated in the majority of human cancers. In neuronal tumors such as neuroblastoma, MYCN is frequently activated by gene amplification, and reducing its expression by RNA interference has been shown to promote growth arrest and apoptosis of tumor cells. From a clinical perspective, RNA interference is not yet a viable option, and small molecule inhibitors of transcription factors are difficult to develop. We therefore planned to identify, at the global level, the genes interacting functionally with MYCN required to promote fitness of tumor cells facing oncogenic stress. To find genes whose inactivation is synthetically lethal to MYCN, we implemented a genome-wide approach in which we carried out a drop-out shRNA screen using a whole genome library that was delivered into isogenic neuroblastoma cell lines expressing or not expressing MYCN. After the screen, we selected for in-depth analysis four shRNAs targeting AHCY, BLM, PKMYT1, and CKS1B. These genes were chosen because they are directly regulated by MYC proteins, associated with poor prognosis of neuroblastoma patients, and inhibited by small molecule compounds. Mechanistically, we found that BLM and PKMYT1 are required to limit oncogenic stress and promote stabilization of the MYCN protein. Cocktails of small molecule inhibitors of CKS1B, AHCY, BLM, and PKMYT1 profoundly affected the growth of all neuroblastoma cell lines but selectively caused death of MYCN-amplified cells. Our findings suggest that drugging the MYCN network is a promising avenue for the treatment of high risk, neuroblastic cancers.SPARKS and the Neuroblastoma Society

    Porous Media Based Modeling of parallel Plate PE-CVD Apparatus

    Get PDF
    The numerous technical applications in deposit metal plates with new materials like SiC and TiC has an advantage to overcome the leaking corrosive behavior and have additional a good electrical behavior. Here we present an application of a porous media to model a homogenized deposition with a parallel plate PE-CVD apparatus. Special geometries of parallel Anodes and cathodes helps to obtain at least a laminar flow field. By the way the delicate arrangement of the anode and cathode has to be simulated. The flux of the precursors are important to simulate to the porous media given as the plasma background. Here we can optimize the transport to the delicate geometry respecting the flux field in the permeable layers. To derive a mathematical model, we deal with a model for the transport and kinetics of the different species. Underlying physical experiments help to approximate the parameters of the numerical model. We introduce a multi regression method to approximate the physical to the mathematical parameters. We present results of some numerical simulations and help to foresee some effects to find on optimal deposition process

    Gold nanoparticle and mean inactivation dose of human intestinal colon cancer HT-29 cells

    Get PDF
    Background: Mean inactivation dose is a useful radiobiological parameter for the comparison of human cell survival curves. Objectives: Given the importance and accuracy of these parameters, in the present study, the radio sensitivity enhancement of colon cancer (HT-29) cells in the presence of gold nanoparticles (GNPs) were studied using the mean inactivation dose (MID). Materials and Methods: Naked-GNPs with 50 nm diameters were incubated with HT-29 cells. The cytotoxicity and uptake of these particles on HT-29 cells were assessed. After determining the optimum GNPs concentration, the cells were incubated with gold nanoparticle for 24 hours. The change in the MID value as well as the radio sensitization enhancement under irradiation with 9 MV X-ray beams in the presence of GNPs were evaluated by multiple (3-(4, 5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium)MTS assay. Results: Cell survival in the presence of GNPs was more than 90% and the maximum uptake of GNPs was observed at 60 Ī¼M of gold nanoparticles. In contrast, in the presence of GNPs combined with radiation, cell survival and MID value significantly decreased, so that the radio sensitization enhancement was 1.4. Conclusions: Due to the significant reduction in the mean inactivation dose of colon cancer cells in the presence of gold nanoparticles, it seems that GNPs are suitable options to achieve a new approach in order to improve radiotherapy efficiency without increasing the prescribed radiation dose

    Palladium Nanoparticles Supported on Ce-Metalā€“Organic Framework for Efficient CO Oxidation and Low-Temperature CO2 Capture

    Get PDF
    In this article, we report the lowest-temperature CO oxidation catalyst supported on metalā€“organic frameworks (MOFs). We have developed a facile, general, and effective approach based on microwave irradiation for the incorporation of Pd nanoparticle catalyst within Ce-MOF. The resulting Pd/Ce-MOF material is a unique catalyst that is capable of CO oxidation at modest temperatures and also of efficient uptake of the product CO2 gas at low temperatures. The observed catalytic activity of this material toward CO oxidation is significantly higher than those of other reported metal nanoparticles supported on MOFs. The high activity of the Pd/Ce-MOF catalyst is due to the presence of Ce(III) and Ce(IV) ions within the metalā€“organic framework support. The Pd nanoparticles supported on the Ce-MOF store oxygen in the form of a thin palladium oxide layer at the particleā€“support interface, in addition to the oxygen stored on the Ce(III)/Ce(IV) centers. Oxygen from these reservoirs can be released during CO oxidation at 373 K. At lower temperatures (273 K), the Pd/Ce-MOF has a significant CO2 uptake of 3.5 mmol/g

    A space-time pseudospectral discretization method for solving diffusion optimal control problems with two-sided fractional derivatives

    Full text link
    We propose a direct numerical method for the solution of an optimal control problem governed by a two-side space-fractional diffusion equation. The presented method contains two main steps. In the first step, the space variable is discretized by using the Jacobi-Gauss pseudospectral discretization and, in this way, the original problem is transformed into a classical integer-order optimal control problem. The main challenge, which we faced in this step, is to derive the left and right fractional differentiation matrices. In this respect, novel techniques for derivation of these matrices are presented. In the second step, the Legendre-Gauss-Radau pseudospectral method is employed. With these two steps, the original problem is converted into a convex quadratic optimization problem, which can be solved efficiently by available methods. Our approach can be easily implemented and extended to cover fractional optimal control problems with state constraints. Five test examples are provided to demonstrate the efficiency and validity of the presented method. The results show that our method reaches the solutions with good accuracy and a low CPU time.Comment: This is a preprint of a paper whose final and definite form is with 'Journal of Vibration and Control', available from [http://journals.sagepub.com/home/jvc]. Submitted 02-June-2018; Revised 03-Sept-2018; Accepted 12-Oct-201
    • ā€¦
    corecore