Possible singlet and triplet superconductivity on honeycomb lattice

We study the possible superconducting pairing symmetry mediated by spin and charge fluctuations on the honeycomb lattice using the extended Hubbard model and the random-phase-approximation method. From $2\%$ to $20\%$ doping levels, a spin-singlet $d_{x^{2}-y^{2}}+id_{xy}$-wave is shown to be the leading superconducting pairing symmetry when only the on-site Coulomb interaction $U$ is considered, with the gap function being a mixture of the nearest-neighbor and next-nearest-neighbor pairings. When the offset of the energy level between the two sublattices exceeds a critical value, the most favorable pairing is a spin-triplet $f$-wave which is mainly composed of the next-nearest-neighbor pairing. We show that the next-nearest-neighbor Coulomb interaction $V$ is also in favor of the spin-triplet $f$-wave pairing.Comment: 6 pages, 4 figure

Mitigation of TGF-β/Smad signaling pathway-associated liver fibrosis by paeoniflorin

Purpose: To evaluate paeoniflorin (PF) as a possible protective agent against liver fibrosis and its likely mechanisms of action.Methods: A rat model of liver fibrosis was induced by carbon tetrachloride (CCl4) injection. Liver damage was determined by serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities. The hydroxyproline content of proteins was measured as an indirect way of assessing collagen deposition. TGF-β1 levels and TGF-β/Smad signaling pathway-related genes and proteins were analyzed by quantitative polymerase chain reaction (qPCR) assay and Western blot assay.Results: After PF administration, serum ALT and AST levels were significantly (p < 0.01) reduced by 34.9 and 37.6 %, respectively. Collagen deposition was also significantly (p < 0.01) reduced by 31.0 %. Hepatic stellate cell activation was significantly inhibited, as evidenced by suppressed α-SMA expression. PF inhibited phospo-Smad 2/3 by elevating Smad 7 level.Conclusion: PF alleviates CCl4-induced liver fibrosis in a dose-dependent manner probably by restoring the balance between activated Smad 2/3 and Smad7. Thus, PF might be a source of a novel anti-fibrotic agent.Keywords: Paeoniflorin, Fibrosis, Liver, TGF-β, Hepatic stellate cell, Smad, Hydroxyprolin

Phenylboronic acid-diol crosslinked 6-<i>O</i>-vinylazeloyl-d-galactose nanocarriers for insulin delivery

A new block polymer named poly 3-acrylamidophenylboronic acid-b-6-O–vinylazeloyl-d-galactose (p(AAPBA-b-OVZG)) was prepared using 3-acrylamidophenylboronic acid (AAPBA) and 6-O-vinylazeloyl-D-galactose (OVZG) via a two-step procedure involving S-1-dodecyl-S-(α', α'-dimethyl-α″-acetic acid) trithiocarbonate (DDATC) as chain transfer agent, 2,2-azobisisobutyronitrile (AIBN) as initiator and dimethyl formamide (DMF) as solvent. The structures of the polymer were examined by Fourier transform infrared spectroscopy (FT-IR) and 1H NMR and the thermal stability was determined by thermal gravimetric analysis (TG/DTG). Transmission electron microscopy (TEM) and dynamic light scattering (DLS) were utilized to evaluate the morphology and properties of the p(AAPBA-b-OVZG) nanoparticles. The cell toxicity, animal toxicity and therapeutic efficacy were also investigated. The results indicate the p(AAPBA-b-OVZG) was successfully synthesized and had excellent thermal stability. Moreover, the p(AAPBA-b-OVZG) nanoparticles were submicron in size and glucose-sensitive in phosphate-buffered saline (PBS). In addition, insulin as a model drug had a high encapsulation efficiency and loading capacity and the release of insulin was increased at higher glucose levels. Furthermore, the nanoparticles showed a low-toxicity in cell and animal studies and they were effective at decreasing blood glucose levels of mice over 96 h. These p(AAPBA-b-OVZG) nanoparticles show promise for applications in diabetes treatment using insulin or other hypoglycemic proteins

Multiphase transport model for heavy ion collisions at RHIC

Using a multiphase transport model (AMPT) with both partonic and hadronic interactions, we study the multiplicity and transverse momentum distributions of charged particles such as pions, kaons and protons in central Au+Au collisions at RHIC energies. Effects due to nuclear shadowing and jet quenching on these observables are also studied. We further show preliminary results on the production of multistrange baryons from the strangeness-exchange reactions during the hadronic stage of heavy ion collisions.Comment: 4 pages, 4 figures, espcrc1.sty included, presented at 15th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions (QM2001), Long Island, New York, January 200