Theoretical study of adsorption of amino acids on graphene and BN sheet in gas and aqueous phase with empirical DFT dispersion correction.

Understanding interactions of biomolecules with nanomaterials at the molecular level is crucial to design new materials for practical use. In the present study, adsorption of three distinct types of amino acids, namely, valine, arginine and aspartic acid, over the surface of structurally analogous but chemically different graphene and BN nanosheets has been explored within the formalism of DFT. The explicit dispersion correction incorporated in the computational methodology improves the accuracy of the results by accounting for long range van der Waals interactions and is essential for agreement with experimental values. The real biological environment has been mimicked by re-optimizing all the model structures in an aqueous medium. The study provides ample evidence in terms of adsorption energy, solvation energy, separation distance and charge analysis to conclude that both the nano-surfaces adsorb the amino acids with release of energy and there are no bonded interactions between the two. The polarity of the BN nanosheet provides it an edge over the graphene surface to have more affinity towards amino acids.

Corticosteroid plus pentoxifylline is not better than corticosteroid alone for improving survival in severe alcoholic hepatitis (COPE trial).

BACKGROUND: Corticosteroids and pentoxifylline reduce short-term mortality in severe alcoholic hepatitis (SAH), but not to the extent desired. Combining both drugs may lead to better survival, but has not yet been studied. AIM: To compare the efficacy of corticosteroids plus pentoxifylline with that of corticosteroids alone in improving survival of SAH patients. METHODS: Of the 111 patients screened, 70 patients with SAH (Maddrey discriminant function (MDF) ≥ 32) were enrolled. Patients with active infection, bleeding, renal failure, or pancreatitis were excluded. Treatment was given for four weeks to group A (n = 36; prednisolone 40 mg/day plus pentoxifylline 400 mg thrice/day) and group B (n = 34; prednisolone 40 mg/day). Patients were followed up for 6 months. Data are expressed as median (range) or percentage. RESULTS: Baseline characteristics of the two groups were similar (MDF group A 78.5 (36.8-140.9), group B 74.9 (45.6-140.2)). Four-week and six-month survival in groups A and B were not significantly different (four-week 72.2 and 73.5%, respectively, p = 1.00; six-month 30.6 and 23.5%, respectively, p = 0.417). At seven days, 55.6% of patients in group A and 64.7% in group B had a Lille score <0.45 (p = 0.473). Six-month survival was significantly higher for patients with a Lille Score <0.45 than for those with a Lille score ≥0.45 (group A 55.5 vs. 0%, p = 0.0006; group B 36 vs. 0%, p = 0.0304). Biological improvement at 28 days was significant for both groups; however, the difference between the groups was not significant. CONCLUSIONS: For patients with severe alcoholic hepatitis, a combination of corticosteroids and pentoxifylline has no additional survival advantage compared with corticosteroids alone.