1,152 research outputs found
Smarr Integral Formula of D-dimensional Stationary Spacetimes in Einstein-\AE ther-Maxwell Theroy
Using the Wald formalism, we investigate the thermodynamics of charged black
holes in D-dimensional stationary spacetimes with or without rotations in
Einstein-\ae ther-Maxwell theory. In particular, assuming the existence of a
scaling symmetry of the action, we obtain the Smarr integral formula, which can
be applied to both Killing and universal horizons. When restricted to
4-dimensional spherically symmetric spacetimes, previous results obtained by a
different method are re-derived.Comment: No figures and tables. Phys. Let. B782 (2018) 723-72
A global bifurcation theorem for a multiparameter positone problem and its application to the one-dimensional perturbed Gelfand problem
We study the global bifurcation and exact multiplicity of positive solutions for u 00(x) + λ fε(u) = 0, − 1 0 is a bifurcation parameter, ε ∈ Θ is an evolution parameter, and Θ ≡ (σ1, σ2) is an open interval with 0 ≤ σ1 < σ2 ≤ ∞. Under some suitable hypotheses on fε , we prove that there exists ε0 ∈ Θ such that, on the (λ, kuk∞)-plane, the bifurcation curve is S-shaped for σ1 < ε < ε0 and is monotone increasing for ε0 ≤ ε < σ2. We give an application to prove global bifurcation of bifurcation curves for the one-dimensional perturbed Gelfand problem
Generation of quasi-monoenergetic protons from thin multi-ion foils by a combination of laser radiation pressure acceleration and shielded Coulomb repulsion
We study theoretically and numerically the acceleration of protons by a combination of laser radiation pressure acceleration and Coulomb repulsion of carbon ions in a multi-ion thin foil made of carbon and hydrogen. The carbon layer helps to delay the proton layer from disruption due to the Rayleigh–Taylor instability, to maintain the quasi-monoenergetic proton layer and to accelerate it by the electron-shielded Coulomb repulsion for much longer duration than the acceleration time using single-ion hydrogen foils. Particle-in-cell simulations with a normalized peak laser amplitude of a_0 = 5 show a resulting quasi-monoenergetic proton energy of about 70 MeV with the foil made of 90% carbon and 10% hydrogen, in contrast to 10 MeV using a single-ion hydrogen foil. An analytical model is presented to explain quantitatively the proton energy evolution; this model is in agreement with the simulation results. The energy dependence of the quasi-monoenergetic proton beam on the concentration of carbon and hydrogen is also studied
Interaction of Proliferation Cell Nuclear Antigen (PCNA) with c-Abl in Cell Proliferation and Response to DNA Damages in Breast Cancer
Cell proliferation in primary and metastatic tumors is a fundamental characteristic of advanced breast cancer. Further understanding of the mechanism underlying enhanced cell growth will be important in identifying novel prognostic markers and therapeutic targets. Here we demonstrated that tyrosine phosphorylation of the proliferating cell nuclear antigen (PCNA) is a critical event in growth regulation of breast cancer cells. We found that phosphorylation of PCNA at tyrosine 211 (Y211) enhanced its association with the non-receptor tyrosine kinase c-Abl. We further demonstrated that c-Abl facilitates chromatin association of PCNA and is required for nuclear foci formation of PCNA in cells stressed by DNA damage as well as in unperturbed cells. Targeting Y211 phosphorylation of PCNA with a cell-permeable peptide inhibited the phosphorylation and reduced the PCNA-Abl interaction. These results show that PCNA signal transduction has an important impact on the growth regulation of breast cancer cells
Factors Affecting Daughter Cells' Arrangement during the Early Bacterial Divisions
On agar plates, daughter cells of Escherichia coli mutually slide and align side-by-side in parallel during the first round of binary fission. This phenomenon has been previously attributed to an elastic material that restricts apparently separated bacteria from being in string. We hypothesize that the interaction between bacteria and the underneath substratum may affect the arrangement of the daughter bacteria. To test this hypothesis, bacterial division on hyaluronic acid (HA) gel, as an alternative substratum, was examined. Consistent with our proposition, the HA gel differs from agar by suppressing the typical side-by-side alignments to a rare population. Examination of bacterial surface molecules that may contribute to the daughter cells' arrangement yielded an observation that, with disrupted lpp, the E. coli daughter cells increasingly formed non-typical patterns, i.e. neither sliding side-by-side in parallel nor forming elongated strings. Therefore, our results suggest strongly that the early cell patterning is affected by multiple interaction factors. With oscillatory optical tweezers, we further demonstrated that the interaction force decreased in bacteria without Lpp, a result substantiating our notion that the side-by-side sliding phenomenon directly reflects the strength of in-situ interaction between bacteria and substratum
Development and Characterization of 20 Microsatellite Markers for Chinese Black Sleeper, Bostrychus sinensis
Twenty microsatellite markers were isolated and characterized from the Chinese black sleeper, Bostrychus sinensis. Loci were screened in 30 individuals from Taiwan. For each locus, the number of alleles varied from 4 to 22 with mean expected and observed heterozygosity of 0.79 and 0.66, respectively. One locus significantly deviated from Hardy-Weinberg equilibrium after Bonferroni correction and no significant linkage disequilibrium was detected. This set of microsatellites will provide a suitable tool for population genetic studies of Chinese black sleeper
A role of ygfZ in the Escherichia coli response to plumbagin challenge
Plumbagin is found in many herbal plants and inhibits the growth of various bacteria. Escherichia coli strains are relatively resistant to this drug. The mechanism of resistance is not clear. Previous findings showed that plumbagin treatment triggered up-regulation of many genes in E. coli including ahpC, mdaB, nfnB, nfo, sodA, yggX and ygfZ. By analyzing minimal inhibition concentration and inhibition zones of plumbagin in various gene-disruption mutants, ygfZ and sodA were found critical for the bacteria to resist plumbagin toxicity. We also found that the roles of YgfZ and SodA in detoxifying plumbagin are independent of each other. This is because of the fact that ectopically expressed SodA reduced the superoxide stress but not restore the resistance of bacteria when encountering plumbagin at the absence of ygfZ. On the other hand, an ectopically expressed YgfZ was unable to complement and failed to rescue the plumbagin resistance when sodA was perturbed. Furthermore, mutagenesis analysis showed that residue Cys228 within YgfZ fingerprint region was critical for the resistance of E. coli to plumbagin. By solvent extraction and HPLC analysis to follow the fate of the chemical, it was found that plumbagin vanished apparently from the culture of YgfZ-expressing E. coli. A less toxic form, methylated plumbagin, which may represent one of the YgfZ-dependent metabolites, was found in the culture supernatant of the wild type E. coli but not in the ΔygfZ mutant. Our results showed that the presence of ygfZ is not only critical for the E coli resistance to plumbagin but also facilitates the plumbagin degradation
Obliteration of Radical Cavities and Total Reconstruction Procedure Without Staging After Canal Wall Down Mastoidectomy: Long-term Results
ObjectivesWe evaluate the long-term surgical and hearing results using a canal wall down mastoidectomy technique followed by cavities obliteration, canal wall reconstruction and ossiculoplasty without staging.MethodsA total of 44 patients between January 2002 and October 2009 were selected and 27 of them were revision cases. Preoperative and postoperative pure tone average (PTA) and air-bone gap (ABG) were assessed and compared 1 and 4 years after surgery.ResultsThe middle ear was well healed and aerated in 40 patients (90.9%) and the tympanic membrane was intact in 42 patients (95.5%). Recurrent cholesteatoma was found on postoperative follow-up in two of the revision patients (7.4%) but none in the primary patients. Seven patients were found to have partial canal bone absorption, but revision surgery was not required. Over 86.4% of all cases were water resistant. Long-lasting improvement and/or preservation of hearing, with maintenance of PTA-ABG closure in 63.7% of all cases within 20 dB, were obtained.ConclusionThe efficacy of our technique after a canal wall down mastoidectomy is satisfactory, and the rate of complication is acceptably low. We believe that our technique could be a convenient method in disease control and providing an excellent basis for hearing restoration simultaneously
A global bifurcation theorem for a multiparameter positone problem and its application to the one-dimensional perturbed Gelfand problem
We study the global bifurcation and exact multiplicity of positive solutions for u 00(x) + λ fε(u) = 0, − 1 0 is a bifurcation parameter, ε ∈ Θ is an evolution parameter, and Θ ≡ (σ1, σ2) is an open interval with 0 ≤ σ1 < σ2 ≤ ∞. Under some suitable hypotheses on fε , we prove that there exists ε0 ∈ Θ such that, on the (λ, kuk∞)-plane, the bifurcation curve is S-shaped for σ1 < ε < ε0 and is monotone increasing for ε0 ≤ ε < σ2. We give an application to prove global bifurcation of bifurcation curves for the one-dimensional perturbed Gelfand problem
Recombinant VP1, an Akt Inhibitor, Suppresses Progression of Hepatocellular Carcinoma by Inducing Apoptosis and Modulation of CCL2 Production
BACKGROUND: The application of viral elements in tumor therapy is one facet of cancer research. Recombinant capsid protein VP1 (rVP1) of foot-and-mouth disease virus has previously been demonstrated to induce apoptosis in cancer cell lines. Here, we aim to further investigate its apoptotic mechanism and possible anti-metastatic effect in murine models of hepatocellular carcinoma (HCC), one of the most common human cancers worldwide. METHODOLOGY/PRINCIPAL FINDINGS: Treatment with rVP1 inhibited cell proliferation in two murine HCC cell lines, BNL and Hepa1-6, with IC₅₀ values in the range of 0.1-0.2 µM. rVP1 also induced apoptosis in these cells, which was mediated by Akt deactivation and dissociation of Ku70-Bax, and resulted in conformational changes and mitochondrial translocation of Bax, leading to the activation of caspases-9, -3 and -7. Treatment with 0.025 µM rVP1, which did not affect the viability of normal hepatocytes, suppressed cell migration and invasion via attenuating CCL2 production. The production of CCL2 was modulated by Akt-dependent NF-κB activation that was decreased after rVP1 treatment. The in vivo antitumor effects of rVP1 were assessed in both subcutaneous and orthotopic mouse models of HCC in immune-competent BALB/c mice. Intratumoral delivery of rVP1 inhibited subcutaneous tumor growth as a result of increased apoptosis. Intravenous administration of rVP1 in an orthotopic HCC model suppressed tumor growth, inhibited intra-hepatic metastasis, and prolonged survival. Furthermore, a decrease in the serum level of CCL2 was observed in rVP1-treated mice. CONCLUSIONS/SIGNIFICANCE: The data presented herein suggest that, via inhibiting Akt phosphorylation, rVP1 suppresses the growth, migration, and invasion of murine HCC cells by inducing apoptosis and attenuating CCL2 production both in vitro and in vivo. Recombinant protein VP1 thus has the potential to be developed as a new therapeutic agent for HCC
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