4,160 research outputs found

    The kHz QPOs as a probe of the X-ray color-color diagram and accretion-disk structure for the atoll source 4U 1728-34

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    We have taken the kHz QPOs as a tool to probe the correlation between the tracks of X-ray color-color diagram (CCD) and magnetosphere-disk positions for the atoll source 4U 1728-34, based on the assumptions that the upper kHz QPO is ascribed to the Keplerian orbital motion and the neutron star (NS) magnetosphere is defined by the dipole magnetic field. We find that from the island to the banana state, the inner accretion disk gradually approaches the NS surface with the radius decreasing from r ~33.0km to ~15.9 km, corresponding to the magnetic field from B(r) ~4.8*10^6 G to ~4.3*10^7 G. In addition, we note the characteristics of some particular radii of magnetosphere-disk -r are: firstly, the whole atoll shape of the CCD links the disk radius range of ~15.9 - 33.0 km, which is just located inside the corotation radius of 4U 1728-34 -r_co ( ~34.4 km), implying that the CCD shape is involved in the NS spin-up state. Secondly, the island and banana states of CCD correspond to the two particular boundaries: (I)-near the corotation radius at r ~27.2 - 33.0 km, where the source lies in the island state; (II)-near the NS surface at r ~15.9 - 22.3 km, where the source lies in both the island and banana states. Thirdly, the vertex of the atoll shape in CCD, where the radiation transition from the hard to soft photons occurs, is found to be near the NS surface at r ~16.4 km. The above results suggest that both the magnetic field and accretion environment are related to the CCD structure of atoll track, where the corotation radius and NS hard surface play the significant roles in the radiation distribution of atoll source.Comment: 6 pages, 3 figures, 1 table, accepted by Astronomy & Astrophysic

    Friezes with coefficients

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    For a cluster algebra A\mathcal{A} over Q\mathbb{Q} of geometric type, we define a frieze\textit{frieze} of A\mathcal{A} to be a Q\mathbb{Q}-algebra homomorphism from A\mathcal{A} to Q\mathbb{Q} that takes positive integer values on all cluster variables and all frozen variables. We present some basic facts on friezes, including frieze testing criteria, the notion of frieze points\textit{frieze points} when A\mathcal{A} is finitely generated, and pullbacks of friezes under certain Q\mathbb{Q}-algebra homomorphisms. For cluster algebras with acyclic seeds, we introduce frieze patterns with coefficients\textit{frieze patterns with coefficients} and we give a sufficient condition for frieze patterns to be equivalent to friezes. For the special cases when A\mathcal{A} has an acyclic seed with either trivial coefficients, principal coefficients, or what we call the BFZ coefficients\textit{BFZ coefficients} (named after A. Berenstein, S. Fomin, and A. Zelevinsky), we identify frieze points of A\mathcal{A} both geometrically as certain positive integral points in explicitly described affine varieties and Lie theoretically (in the finite case) in terms of reduced double Bruhat cells and generalized minors on the associated semi-simple Lie groups.Comment: 47 page

    In vitro micro-propagation of Longiflorum-Asiatic (LA) hybrids lily (Lilium) cultivar ‘eyeliner’

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    Bulblets propagation by tissue culture was one of the key techniques in the production of lily (Lilium) bulbs. Therefore, in vitro micro propagation of lily bulblets was studied in detail in this paper. L A hybrids lily cultivar ‘eyeliner’ was selected as the materials. By using the method of orthogonal design, the following were concluded from the research: the optimum treatment and disinfection methods of ‘eyeliner’ bulb scales was soaking in 1:500 carbendazim solution for 30 min, disinfection in 75% alcohol for 10 to 60 s, disinfection in 2% NaClO solution for 15 min; the optimum medium for bud induction of ‘eyeliner’ was MS + 0.5 mg·L-1 6-benzyl aminopurine (6-BA) + 0.1 mg·L-1 naphlene acetic acid (NAA) + 90 g·L-1 sucrose, and 25°C and in darkness; the optimum medium for bulblets induction of ‘eyeliner’ was 2MS + 1.0 mg·L-1 6-BA + 0.5 mg·L-1 NAA + sucrose 90 g·L-1 + Paclobutrazol (PP333) 2 mg·L-1; the optimum culture condition for bulblets induction of ‘eyeliner’ was 20°C, 14 h·day-1 lightness + 10 h·day-1 darkness. The optimum medium for rooting culture of ‘eyeliner’ was ½ MS + 0.8 mg·L-1 NAA + 3 g·L-1 activated charcoal, 20°C, 14 h·day-1 lightness + 10 h·day-1 darkness.Keywords: Lily bulb, orthogonal experiment, in vitro micro propagatio

    MiRNA-145 increases therapeutic sensibility to gemcitabine treatment of pancreatic adenocarcinoma cells.

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    Pancreatic adenocarcinoma is one of the most leading causes of cancer-related deaths worldwide. Although recent advances provide various treatment options, pancreatic adenocarcinoma has poor prognosis due to its late diagnosis and ineffective therapeutic multimodality. Gemcitabine is the effective first-line drug in pancreatic adenocarcinoma treatment. However, gemcitabine chemoresistance of pancreatic adenocarcinoma cells has been a major obstacle for limiting its treatment effect. Our study found that p70S6K1 plays an important role in gemcitabine chemoresistence. MiR-145 is a tumor suppressor which directly targets p70S6K1 for inhibiting its expression in pancreatic adenocarcinoma, providing new therapeutic scheme. Our findings revealed a new mechanism underlying gemcitabine chemoresistance in pancreatic adenocarcinoma cells

    Data Verification in Integrated RFID Systems

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    Inherent Safer Design for Chemical Process of 1,4-dioldiacetate-2-butene Oxidized by Ozone

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    PresentationOxidation reaction is the typical thermal runaway reaction. The reaction of 1,4-dioldiacetate-2- Butene oxidized by ozone was chosen to study the thermal hazards during the chemical process and the inherent safer designs (ISD) were proposed after analysis. The Qualitative Assessment for Inherently Safer Design (QAISD) was used to identify the risk during the chemical process. Meanwhile, the Reaction Calorimeter (RC1e) was used to analyze the thermal hazards of the chemical process. Two Inherent safer designs were proposed to increase the safe level of the process. ISD I is the improved reaction condition of reaction temperature at -5°C and ventilation rate of 200L•h-1, as well, ISDII is using a tubular reactor. The results indicate that the classification of the reaction hazard was lower with improvements of two ISDs, and the severity was reduced by 43%. Moreover, the inherent safety level of the reaction was increased by ISD I &IIof 63% and 43.4% respectively, which both have positive effects on inherent safety theories of "minimize", "substitute" and "moderate"

    Improving the Accuracy of Density Functional Theory (DFT) Calculation for Homolysis Bond Dissociation Energies of Y-NO Bond: Generalized Regression Neural Network Based on Grey Relational Analysis and Principal Component Analysis

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    We propose a generalized regression neural network (GRNN) approach based on grey relational analysis (GRA) and principal component analysis (PCA) (GP-GRNN) to improve the accuracy of density functional theory (DFT) calculation for homolysis bond dissociation energies (BDE) of Y-NO bond. As a demonstration, this combined quantum chemistry calculation with the GP-GRNN approach has been applied to evaluate the homolysis BDE of 92 Y-NO organic molecules. The results show that the ull-descriptor GRNN without GRA and PCA (F-GRNN) and with GRA (G-GRNN) approaches reduce the root-mean-square (RMS) of the calculated homolysis BDE of 92 organic molecules from 5.31 to 0.49 and 0.39 kcal mol−1 for the B3LYP/6-31G (d) calculation. Then the newly developed GP-GRNN approach further reduces the RMS to 0.31 kcal mol−1. Thus, the GP-GRNN correction on top of B3LYP/6-31G (d) can improve the accuracy of calculating the homolysis BDE in quantum chemistry and can predict homolysis BDE which cannot be obtained experimentally

    Carvacrol Alleviates Prostate Cancer Cell Proliferation, Migration, and Invasion through Regulation of PI3K/Akt and MAPK Signaling Pathways

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    TRPM7 is a potential therapeutic target for treatment of prostate cancer. In this study, we investigated the effects of nonselective TRPM7 inhibitor carvacrol on cell proliferation, migration, and invasion of prostate cancer PC-3 and DU145 cells. Our results showed that carvacrol blocked TRPM7-like currents in PC-3 and DU145 cells and reduced their proliferation, migration, and invasion. Moreover, carvacrol treatment significantly decreased MMP-2, p-Akt, and p-ERK1/2 protein expression and inhibited F-actin reorganization. Furthermore, consistently, TRPM7 knockdown reduced prostate cancer cell proliferation, migration, and invasion as well. Our study suggests that carvacrol may have therapeutic potential for the treatment of prostate cancer through its inhibition of TRPM7 channels and suppression of PI3K/Akt and MAPK signaling pathways
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