Jamming transition in a highly dense granular system under vertical vibration

The dynamics of the jamming transition in a three-dimensional granular system under vertical vibration is studied using diffusing-wave spectroscopy. When the maximum acceleration of the external vibration is large, the granular system behaves like a fluid, with the dynamic correlation function G(t) relaxing rapidly. As the acceleration of vibration approaches the gravitational acceleration g, the relaxation of G(t) slows down dramatically, and eventually stops. Thus the system undergoes a phase transition and behaves like a solid. Near the transition point, we find that the structural relaxation shows a stretched exponential behavior. This behavior is analogous to the behavior of supercooled liquids close to the glass transition.Comment: 5 pages, 5 figures, accepted by Phys. Rev.

Preparation and evaluation of polymeric microparticulates for improving cellular uptake of gemcitabine

Ji-Ho Lim1,*, Sung-Kyun You1,*, Jong-Suep Baek1, Chan-Ju Hwang1, Young-Guk Na1, Sang-Chul Shin2, Cheong-Weon Cho11College of Pharmacy and Institute of Drug Research and Development, Chungnam National University, Gungdong, Yuseonggu, Daejeon, South Korea, 2College of Pharmacy, Chonnam National University, Buggu, Gwangju, South Korea *These authors contributed equally to this workBackground: Gemcitabine must be administered at high doses to elicit the required therapeutic response because of its very short plasma half-life due to rapid metabolism. These high doses can have severe adverse effects.Methods: In this study, polymeric microparticulate systems of gemcitabine were prepared using chitosan as a mucoadhesive polymer and Eudragit L100-55 as an enteric copolymer. The physicochemical and biopharmaceutical properties of the resulting systems were then evaluated.Results: There was no endothermic peak for gemcitabine in any of the polymeric gemcitabine microparticulate systems, suggesting that gemcitabine was bound to chitosan and Eudragit L100-55 and its crystallinity was changed into an amorphous form. The polymeric gemcitabine microparticulate system showed more than 80% release of gemcitabine in 30 minutes in simulated intestinal fluid. When mucin particles were incubated with gemcitabine polymeric microparticulates, the zeta potential of the mucin particles was increased to 1.57 mV, indicating that the polymeric gemcitabine microparticulates were attached to the mucin particles. Furthermore, the F53 polymeric gemcitabine microparticulates having 150 mg of chitosan showed a 3.8-fold increased uptake of gemcitabine into Caco-2 cells over 72 hours compared with gemcitabine solution alone.Conclusion: Overall, these results suggest that polymeric gemcitabine microparticulate systems could be used as carriers to help oral absorption of gemcitabine.Keywords: gemcitabine, polymeric microparticulates, mucoadhesive, enteric coating, cellular uptake, oral absorptio

Efficacy and Tolerability of GCSB-5 for Hand Osteoarthritis: A Randomized, Controlled Trial

AbstractPurposeThe aim of this study was to investigate the efficacy and tolerability of GCSB-5, a mixture of 6 purified herbal extracts, in treating hand osteoarthritis (OA).MethodsA randomized, double-blind, placebo-controlled trial enrolled 220 patients with hand OA who had baseline a visual analog scale joint pain score of >30 of 100 mm at 3 hospitals between September 2013 and November 2014. After randomization, patients were allocated to receive oral GCSB-5 600 mg or placebo, bid for 12 weeks. The primary end point was the change in the Australian/Canadian OA Hand Index (AUSCAN)-defined pain score at 4 weeks relative to baseline. Secondary end points included the frequency Outcome Measures in Rheumatology–OA Research Society International (OMERACT-OARSI)-defined response at 4, 8, 12, and 16 weeks after randomization.FindingsThe allocated treatment was received by 109 and 106 patients in the GCSB-5 and placebo groups, respectively. At 4 weeks, the median (interquartile range) change in AUSCAN pain score relative to baseline was significantly greater in the GCSB-5 group than in the placebo group (–9.0 [–23.8 to –0.4] vs –2.2 [–16.7 to 6.0]; P = 0.014), with sustained improvement at 8, 12, and 16 weeks (P = 0.039). The GCSB-5 group also had a significantly greater OMERACT-OARSI–defined response rate than did the placebo group at 4 weeks (44.0% vs 30.2%), 8 weeks (51.4% vs 35.9%), 12 weeks (56.9% vs 40.6%), and 16 weeks (50.5% vs 37.7%) (P = 0.0074). The 2 treatments exhibited comparable safety profiles.ImplicationsGCSB-5 was associated with improved symptoms of hand OA, with good tolerability, in these patients. GCSB-5 may be a well-tolerated alternative of, or addition to, the treatment of hand OA. ClinicalTrials.gov identifier: NCT01910116

Clinical Outcome of Urgent Coronary Artery Bypass Grafting

Urgent coronary artery bypass grafting (CABG) has a higher mortality rate than elective CABG. The purpose of this study was to evaluate the clinical outcome of urgent CABG. From July 1992 to May 2005, 104 patients underwent urgent CABG. All patients required an urgent surgical revascularization within 24 hr of diagnostic coronary angiography. In-hospital mortality after urgent CABG was 17.3% (18/104). We compared preoperative characteristics and postoperative clinical outcomes between the survival group (n=86) and the mortality group (n=18). The mean age was 61.7 yr (range, 35-83). The most common cause of mortality was low cardiac output. The independent preoperative risk factors of mortality included advanced age (>70 yr) (OR=3.998, p=0.046), preoperative shock status (OR=6.542, p=0.011), and low ejection fraction (<40%) (OR=4.492, p=0.034). Other risk factors of mortality included prolonged cardiopulmonary bypass time, prolonged ventilator use, and extended intensive care unit stay. The 10-yr actuarial survival rate was 61%. Although the operative mortality rate was high after urgent CABG, a favorable long-term clinical outcome can be expected if the patients survive

Phase equilibria, dissociation enthalpies, and Raman spectroscopic analyses of N2 + tetra-n-butyl ammonium chloride (TBAC) semiclathrates

The thermodynamic phase behaviors, dissociation enthalpies, and Raman spectra of N2 + tetra-n-butyl ammonium chloride (TBAC) + water systems were measured in order to investigate the enclathration of N2 in TBAC semiclathrates. The three-phase (H-Lw-V) equilibria of the N2 + TBAC (1.0, 3.3, and 5.0 mol%) semiclathrates measured using a high pressure vessel as well as a high pressure micro-differential scanning calorimeter (HP ??-DSC) indicated that the N2 + TBAC semiclathrates have significant stability in the thermodynamic equilibrium compared with the N2 gas hydrate and that they also exhibit maximum thermodynamic stability at 3.3 mol%, which corresponds to the stoichiometric concentration of TBAC??29.7H2O. The dissociation enthalpies of the N2 + TBAC semiclathrates were determined from the endothermic dissociation thermograms of a HP ??-DSC under pressure. The Raman spectroscopic results clearly demonstrated that N2 molecules are enclathrated in the cages of the TBAC semiclathrate. From the overall experimental results, TBAC is expected to be an effective semiclathrate former that can reduce the equilibrium dissociation pressure or enhance the equilibrium dissociation temperature for enclosing N2 molecules as a guest in the vacant cages of TBAC semiclathrates.close0

Guest gas enclathration in tetra-n-butyl ammonium chloride (TBAC) semiclathrates: Potential application to natural gas storage and CO2 capture

The enclathration of guest gases such as CH4 and CO2 in tetra-n-butyl ammonium chloride (TBAC) semiclathrates and their potential application to natural gas storage and CO2 capture were examined with a primary focus on stability condition measurements and cage filling characteristics. The phase behaviors clearly demonstrated that the double CH4 (or CO2) + TBAC semiclathrates yielded a significantly enhanced thermodynamic stability. In particular, the highest stabilization occurred at 3.3 mol%, the stoichiometric concentration of TBAC??29.7H2O. The cage-dependent 13C NMR chemical shift identified CH4 molecules enclathrated in the small 512 cages of the double TBAC semiclathrates. CO2 inclusion in the double TBAC semiclathrate was also confirmed using Raman spectroscopy. In addition, the dissociation enthalpy and the dissociation temperature of the TBAC semiclathrate under atmospheric pressure were measured to be 204.8 ?? 1.7 J/g and 288.0 K, respectively, by a differential scanning calorimeter. The experimental results demonstrate that TBAC semiclathrates can potentially be used for gas storage and CO2 capture due to their high thermodynamic stability and favorable enclathration characteristics of guest gases.close2

Effects of dissolved CO2 levels on the growth of Mannheimia succiniciproducens and succinic acid production

A capnophilic rumen bacterium Mannheimia succiniciproducens produces succinic acid as a major fermentation end product under CO2-rich anaerobic condition. Since succinic acid is produced by carboxylation of C3 compounds during the fermentation, intracellular CO2 availability is important for efficient succinic acid formation. Here, we investigated the metabolic responses of M. succiniciproducens to the different dissolved CO2 concentrations (0-260 mM). Cell growth was severely suppressed when the dissolved CO2 concentration was below 8.74 mM. On the other hand, cell growth and succinic acid production increased proportionally as the dissolved CO2 concentration increased from 8.74 to 141 mM. The yields of biomass and succinic acid on glucose obtained at the dissolved CO2 concentration of 141 mM were 1.49 and 1.52 times higher, respectively, than those obtained at the dissolved CO2 concentration of 8.74 mM. It was also found that the additional CO2 source provided in the form of NaHCO3, MgCO3, or CaCO3 had positive effects 1 on cell growth and succinic acid production. However, growth inhibition was observed when excessive bicarbonate salts were added. By the comparison of the activities of key enzymes, it was found that PEP carboxylation by PEP carboxykinase (PckA) is the most important for succinic acid production as well as the growth of M. succiniciproducens by providing additional ATP.11Nsciescopu