2,342 research outputs found
Running of the Spectral index in Deformed Matter Bounce Scenarios with Hubble-rate-dependent Dark Energy
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 and 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 . However, by extending the power series up to ,
, and estimating a set of consistent
parameters, we obtain the spectral index , a small negative value of
running and tensor to scalar ratio , which these reval a
degeneracy between deformed matter bounce scenario with RVM-DE and inflationary
cosmology.Comment: 27 pages, 6 figure
Identification and pharmacological inactivation of the MYCN gene network as a therapeutic strategy for neuroblastic tumor cells
This research was originally published in Journal of Biological Chemistry. Olesya Chayka, Cosimo Walter D’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. © 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
Heart surgery waiting time: Assessing the effectiveness of an action
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 patient’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 patients’ emotionally readiness. © 2015, Iranian Red Crescent Medical Journal
Molecular Dynamics Simulation of Cross-Linked Epoxy Polymers: the Effect of Force Field on the Estimation of Properties
In this paper, the molecular dynamics method was used to calculate the physical and mechanical properties of the cross-linked epoxy polymer composed of diglycidyl ether of bisphenol-A (DGEBA) as resin and diethylenetriamine (DETA) as curing agent. Calculation of the properties was performed using the constant-strain (static) approach. A series of independent simulations were carried out based on four widely used force fields; COMPASS, PCFF, UFF and Dreiding. Proper comparisons between the results and also with experimental observations were made to find the most suitable force field for molecular dynamics simulation of polymer materials.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3096
Coupled Coincidence And Common Fixed Point Theorems For Mappings In Partially Ordered Metric Spaces
In this paper, we prove coupled coincidence points and common fixed points theorem for two mappings satisfying various contractive conditions in partially ordered metric spaces. Our results will generalize and extend some recent results in fixed point theory. Keywords: Common Fixed Point, Coupled Fixed Point, Coupled Coincidence Point, Mixed -Monotone Property, Partially Ordered Set
Gold nanoparticle and mean inactivation dose of human intestinal colon cancer HT-29 cells
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 μM 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
A Comparative Study of the Oxidation and Wet Chemical Methods for Uncapping the Multi-Walled Carbon Nanotubes
Carbon nanotubes (CNTs) are generally capped at either end with a half of a fullerene. Hence, for storing different materials into the hollow space of CNTs, their caps need to be removed in the first step. In this study, we studied both the oxidation and wet chemical (acid-based) methods for opening the multi-walled carbon nanotubes (MWCNTs). In The oxidation method, 250 mg of CNTs were heated at 810 °C for 15 minutes in the air, and yielded about 56 % opened CNTs, while 78 % weight loss was recorded. The second sample with the same weight of the sample 1 was treated at 780 °C for 15 min. The weight loss and yielded uncapped CNTs were recorded 36 % and 47 %, respectively. The 780 °C was observed to be more appropriate than the higher temperature. In the acid-based method, the CNTs were refluxed in boiling nitric acid (65 % analar grade) at 110 °C for 12 h. In this case, about 80 % of the CNTs were thoroughly opened without any weight loss. The acid-based method was finally deduced to be more economical and efficient than the oxidation method.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3094
Efecto de la presión de confinamiento y el método de deposición sobre la respuesta de corte no drenada de arena de densidad media
This study examines the effects of the confining pressure and sample preparation method on the shearing behavior shown by sand from the Chlef River (Algeria). Undrained monotonic triaxial compression tests were performed on samples with an initial relative density of 50% at initial confining pressures of 50 to 200 kPa. Samples were prepared using two depositional methods: dry funnel pluviation and wet deposition. Our results reveal marked differences in the undrained shearing responses produced under identical conditions of density and stress and therefore determined by the soil fabric. Thus, at low confining pressures, samples prepared by the wet deposition method showed complete static liquefaction (zero effective confining pressure and zero stress difference). For both sample types, as confining pressures increased, effective stress paths exhibited increasing resistance to liquefaction indicated by increasing dilatant tendencies.En este trabajo se han estudiado los efectos de la presión de confinamiento y los métodos de preparación de muestras sobre el comportamiento de rotura de arena Chlef. Los resultados de las pruebas sin escurrir monótona de compresión triaxial realizadas en muestras con una densidad relativa inicial del 50% y presiones de confinamiento inicial variaron desde 50 hasta 200 kPa. Las muestras fueron preparadas por dos métodos de deposición seca con embudo de pluviacion y deposición húmeda. Se encontró que existía una marcada diferencia en el comportamiento sin escurrir a pesar de que las condiciones de la densidad y el estrés eran idénticas. La conclusión fue que la estructura del suelo fue la responsable de este resultado. Los resultados también indicaron que a baja presión de confinamiento, las muestras preparadas mediante un método de deposición húmedo, completan la licuefacción estática (ninguna presión de confinamiento efectiva y ninguna diferencia de estress). Los resultados indicaron también que a bajas presiones de confinamiento, los especímenes reconstituida por el método de deposición húmeda expuesto licuefacción estática completa (cero de la presión efectiva de confinamiento y cero diferencia de estrés). Como las presiones de confinamiento se incrementaron, las trayectorias de tensiones efectivas aumentaron la resistencia a la licuefacción, mostrando aumento de la tendencia dilatante
Estudio en laboratorio sobre licuefacción de arena parcialmente saturada
This experimental study was designed to assess the effects of soil water saturation on the liquefaction of Hostun RF sand. Cyclic undrained triaxial tests were conducted at different soil saturation levels, as given by Skempton’s coefficient, and liquefaction potential curves constructed for each value of this coefficient. Our findings indicate that a lower soil saturation level results in the increased resistance of the sand to liquefaction, in agreement with the tendency observed in other sands. In addition, the variation in sand resistance to liquefaction produced with Skempton’s coefficient was found to be consistent with the semi-empirical relation proposed by Yang et al. (2004).Este estudio experimental fue diseñado para comprobar los efectos de la saturación de agua en suelos bajo la licuefacción de arena RF Hostun. Tests cíclicos de tipo triaxial no drenado fueron elaborados a diferentes niveles de saturación del suelo, como se obtiene por el coeficiente de Skempton, y se obtuvieron curvas de potencial de licuefacción para cada uno de los valores de este coeficiente. Nuestros resultados indican que un nivel de saturación bajo de suelo durante el incremento de la resistencia de la arena a la licuefacción, estando de acuerdo con la tendencia observada en otras arenas. Por otro lado, se observó que la variación de la resistencia de las arenas a la licuefacción producida mediante el coeficiente de Skempton es consistente con la relación semiempírica propuesta por Yang et al. (2004)
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