500 research outputs found

    Blow up solutions to a viscoelastic fluid system and a coupled Navier-Stokes/Phase-Field system in R^2

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    We find explicit solutions to both the Oldroyd-B model with infinite Weissenberg number and the coupled Navier-Stokes/Phase-Field system. The solutions blow up in finite time.Comment: 5 page

    Quantum theory of electronic double-slit diffraction

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    The phenomena of electron, neutron, atomic and molecular diffraction have been studied by many experiments, and these experiments are explained by some theoretical works. In this paper, we study electronic double-slit diffraction with quantum mechanical approach. We can obtain the results: (1) When the slit width aa is in the range of 3λ∼50Ξ»3\lambda\sim 50\lambda we can obtain the obvious diffraction patterns. (2) when the ratio of d+aa=n(n=1,2,3,β‹…β‹…β‹…)\frac{d+a}{a}=n (n=1, 2, 3,\cdot\cdot\cdot), order 2n,3n,4n,β‹…β‹…β‹…2n, 3n, 4n,\cdot\cdot\cdot are missing in diffraction pattern. (3)When the ratio of d+aaβ‰ n(n=1,2,3,β‹…β‹…β‹…)\frac{d+a}{a}\neq n (n=1, 2, 3,\cdot\cdot\cdot), there isn't missing order in diffraction pattern. (4) We also find a new quantum mechanics effect that the slit thickness cc has a large affect to the electronic diffraction patterns. We think all the predictions in our work can be tested by the electronic double-slit diffraction experiment.Comment: 9pages, 14figure

    Inhibitory role of peroxisome proliferator-activated receptor gamma in hepatocarcinogenesis in mice and in vitro

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    Although peroxisome proliferator-activated receptor gamma (PPARΞ³) agonist have been shown to inhibit hepatocellular carcinoma (HCC) development, the role of PPARΞ³ in hepatocarcinogenesis remains unclear. We investigated the therapeutic efficacy of PPAR

    The atomic gas of star-forming galaxies at z∼\sim0.05 as revealed by the Five-hundred-meter Aperture Spherical Radio Telescope

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    We report new HI observations of four z∼\sim0.05 star-forming galaxies undertaken during the commissioning phase of the Five-hundred-meter Aperture Spherical Radio Telescope (FAST). FAST is the largest single-dish telescope with a 500 meter aperture and a 19-Beam receiver. Exploiting the unprecedented sensitivity provided by FAST, we aim to study the atomic gas, via the HI 21cm emission line, in low-zz star-forming galaxies taken from the Valpara\'iso ALMA/APEX Line Emission Survey (VALES) project. Together with previous ALMA CO(J=1βˆ’0J=1-0) observations, the HI data provides crucial information to measure the gas mass and dynamics. As a pilot HI survey, we targeted four local star-forming galaxies at z∼0.05z\sim0.05. In particular, one of them has already been detected in HI by the Arecibo Legacy Fast ALFA survey (ALFALFA), allowing a careful comparison. We use an ON-OFF observing approach that allowed us to reach an rms of 0.7mJy/beam at a 1.7km/s velocity resolution within only 20 minutes ON-target integration time. We demonstrate the great capabilities of the FAST 19-beam receiver for pushing the detectability of the HI emission line of extra-galactic sources. The HI emission line detected by FAST shows good consistency with the previous ALFALFA results. Our observations are put in context with previous multi-wavelength data to reveal the physical properties of these low-zz galaxies. We find that the CO(J=1βˆ’0J=1-0) and HI emission line profiles are similar. The dynamical mass estimated from the HI data is an order of magnitude higher than the baryon mass and the dynamical mass derived from the CO observations, implying that the mass probed by dynamics of HI is dominated by the dark matter halo. In one case, a target shows an excess of CO(J=1βˆ’0J=1-0) in the line centre, which can be explained by an enhanced CO(J=1βˆ’0J=1-0) emission induced by a nuclear starburst showing high velocity dispersion.Comment: 5 pages, 3 figures, 2 appendix, A&A Letter accepte

    Synthesis of Novel Flower-Like Zn(OH)F via a Microwave-Assisted Ionic Liquid Route and Transformation into Nanoporous ZnO by Heat Treatment

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    Zinc hydroxide fluoride (Zn(OH)F) with novel flower-like morphology has been prepared via a microwave-assisted ionic liquid route. The flower-like Zn(OH)F particle has six petals and every petal is composed of lots of acicular nano-structure. Nanoporous ZnO is obtained by thermal decomposition of as-prepared Zn(OH)F in air, and the flower-like morphology is well retained. In the process of synthesis, ionic liquid 1-Butyl-3-methylimidazolium tetrafluoroborate is used as both the reactant and the template

    Suspension culture combined with chemotherapeutic agents for sorting of breast cancer stem cells

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    <p>Abstract</p> <p>Background</p> <p>Cancer stem cell (CSC) hypothesis has not been well demonstrated by the lack of the most convincing evidence concerning a single cell capable of giving rise to a tumor. The scarcity in quantity and improper approaches for isolation and purification of CSCs have become the major obstacles for great development in CSCs. Here we adopted suspension culture combined with anticancer regimens as a strategy for screening breast cancer stem cells (BrCSCs). BrCSCs could survive and be highly enriched in non-adherent suspension culture while chemotherapeutic agents could destroy most rapidly dividing cancer cells and spare relatively quiescent BrCSCs.</p> <p>Methods</p> <p>TM40D murine breast cancer cells were cultured in serum-free medium. The expression of CD44<sup>+</sup>CD24<sup>- </sup>was measured by flow cytometry. Cells of passage 10 were treated in combination with anticancer agents pacilitaxel and epirubicin at different peak plasma concentrations for 24 hours, and then maintained under suspension culture. The rate of apoptosis was examined by flow cytometry with Annexin-V fluorescein isothiocyanate (FITC)/propidium iodide (PI) double staining method. Selected cells in different amounts were injected subcutaneously into BALB/C mice to observe tumor formation.</p> <p>Results</p> <p>Cells of passage 10 in suspension culture had the highest percentage of CD44<sup>+</sup>CD24<sup>- </sup>(about 77 percent). A single tumor cell in 0.35 PPC could generate tumors in 3 of 20 BALB/C mice.</p> <p>Conclusion</p> <p>Suspension culture combined with anticancer regimens provides an effective means of isolating, culturing and purifying BrCSCs.</p

    Oscillating Asymmetric Dark Matter

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    We study the dynamics of dark matter (DM) particle-antiparticle oscillations within the context of asymmetric DM. Oscillations arise due to small DM number-violating Majorana-type mass terms, and can lead to recoupling of annihilation after freeze-out and washout of the DM density. We derive the density matrix equations for DM oscillations and freeze-out from first principles using nonequilibrium field theory, and our results are qualitatively different than in previous studies. DM dynamics exhibits particle-vs-antiparticle "flavor" effects, depending on the interaction type, analogous to neutrino oscillations in a medium. "Flavor-sensitive" DM interactions include scattering or annihilation through a new vector boson, while "flavor-blind" interactions include scattering or s-channel annihilation through a new scalar boson, or annihilation to pairs of bosons. In particular, we find that flavor-sensitive annihilation does not recouple when coherent oscillations begin, and that flavor-blind scattering does not lead to decoherence.Comment: 23 pages, 4 figures, A typo fixed, References adde

    Hepatotoxicity or Hepatoprotection? Pattern Recognition for the Paradoxical Effect of the Chinese Herb Rheum palmatum L. in Treating Rat Liver Injury

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    The hepatotoxicity of some Chinese herbs has been a cause for concern in recent years. However, some herbs, such as rhubarb, have been documented as having both therapeutic and toxic effects on the liver, leading to the complex problem of distinguishing the benefits from the risks of using this herb. To comparatively analyze the dose-response relationship between rhubarb and hepatic health, we administrated total rhubarb extract(RE) to normal and carbon tetrachloride(CCl4)-treated rats for 12 weeks at 4 dosage levels(2.00, 5.40, 14.69 and 40.00 gΒ·kgβˆ’1, measured as the quantity of crude material), followed by biochemical and histopathological tests of the rats' livers. A composite pattern was extracted by factor analysis, using all the biochemical indices as variables, into a visual representation of two mathematically obtained factors, which could be interpreted as the fibrosis factor and the cellular injury factor, according to the values of the variable loadings. The curative effect of administering the two lowest dosages of RE to CCl4-treated rats was mainly expressed as a decrease in the extent of cellular injury. The hepatoprotective mechanism of RE might be related to its antioxidant effect, the antagonism of the free radical damage to hepatocytes caused by CCl4. By contrast, the RE-induced liver damage was mainly expressed as a significant increase in the amount of fibrosis in both normal rats at all dosage levels and CCl4-treated rats at the two highest dosage levels. Therefore, the hepatotoxic potential of RE could be attributable to the liver cell fibrosis induced by high doses of the herb. This study illustrates the bidirectional potential of rhubarb and demonstrates the feasibility of using factor analysis to study the dose-response relationships between herbal medicines and hepatotoxicity or the healing effects of these herbs by extracting the underlying interrelationships among a number of functional bio-indices in a holistic manner

    A meta-analysis on the effect of corticosteroid therapy in Kawasaki disease

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    The current recommended therapy for Kawasaki disease (KD) is the combination of intravenous immunoglobulin (IVIG) and aspirin. However, the role of corticosteroid therapy in KD remains controversial. Using meta-analysis, this study aimed to investigate the efficacy of corticosteroid therapy in KD by comparing it with standard IVIG and aspirin therapy. We included all related randomized and quasi-randomized controlled trials by searching Medline, the Cochrane Central Register of Controlled Trials, EMBASE, Pub Med, Chinese BioMedical Literature Database, China National Knowledge Infrastructure, and the Japanese database (Japan Science and Technology) as well as hand searches of selected references. Data collection and meta-analysis were performed to evaluate the effect of corticosteroids. Our search yielded 11 studies; 7 of which evaluated the effect of corticosteroid for primary therapy in KD, and 4 investigated the effect of corticosteroid therapy in IVIG-resistant patients. Meta-analysis of these studies revealed a significant reduction in the rates of initial treatment failure among patients who received corticosteroid therapy in combination with IVIG compared to IVIG alone (odds ratio (OR) = 0.50; 95% CI, 0.32~0.79; p = 0.003). Furthermore, the use of corticosteroids reduced the duration of fever and the time required for C-reactive protein to return to normal. Our data did not show any significant increase in the incidence of coronary artery lesions or coronary aneurysms (OR = 0.67; 95% CI, 0.35~1.28; p = 0.23) in the corticosteroid group. Conclusion. Corticosteroid combined with IVIG in primary treatment or as treatment of IVIG-resistant patients improved clinical course without increasing coronary artery lesions in children with acute KD
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