Heavy-quark mesons in the diabatic approach: string breaking and the quarkoniumlike spectrum

The Born-Oppenheimer approximation provides a description of heavy-quark mesons firmly based on lattice QCD, but its validity is limited to the lightest states lying far below the first open-flavour meson-meson threshold. This limitation can be overcome in the diabatic framework, a formalism first introduced in molecular physics, where the dynamics is encoded in a potential matrix whose elements can be derived from unquenched lattice QCD studies of string breaking. The off-diagonal elements of the potential matrix provide interaction between heavy quark-antiquark and meson-meson pairs, from which the mixing of quarkonium states with molecular components and the OZI-allowed strong decay widths are directly calculated. This allows for a QCD-based unified description of conventional quarkonium and unconventional mesons containing quark-antiquark and meson-meson components, what has proved to be successful for charmoniumlike and bottomoniumlike resonances.

Potential Application of Banana Peel Flour in Biofilm

Agribusiness is a major generator of waste, which generates significant environmental impacts. However, these residues can have several applications, thus having added value. Among all fruits, the banana has the highest rate of consumption in Brazil, consequently producing large amounts of peel. This work aims to get and characterize the banana peel flour for further application in biofilm production. We performed the physicalchemical characterization of the banana peel and the flour by crushing and drying in an oven (60 °C/24 h). Subsequently, we wash and delignification the pulp for its extraction. The results obtained 43% of total fiber in the flour and, at the end of the delignification process, 1.45 g of cellulose. Therefore, the banana peel presents itself as a potential matrix for application in the production of biofilm.

Effect of Impurities on a Two-Dimensional Dodecagonal Quasicrystal

Langevin dynamics simulations are performed to examine how impurities affect two-dimensional dodecagonal quasicrystals. We assumed that the interaction potential between two particles is the Lennard-Jones-Gauss potential if at least one of these particles is a matrix particle and that the interaction potential between two impurities is the Lennard-Jones potential. Matrix particles and impurities impinge with constant rates on the substrate created by a part of a dodecagonal quasicrystal consisting of square and triangular tiles. The dependences of the twelve-fold rotational order and the number of shield-like tiles on the impurity density are examined after sufficient solid layers are grown. While the change in the twelve-fold rotational symmetry is small, the number of shield-like tiles in the solid increases greatly with increasing impurity density.

Melanin, a potential new matrix material for recombinant His-tag protein purification

Nickel-Sepharose (Ni-Sepharose) has been being applied as the most common matrix in purifying His-tag proteins based on the affinity interaction between histidine residues and Ni2+ ion. However, Sepharose still comes at high cost for this purification purpose, especially in developing countries as Vietnam. Here, we show for the first time that melanin from ink sacs of squids which is considered as biowaste in the food industry, can be used as a new potential matrix material instead of Sepharose. We utilized either melanin or melanin charged with metal ions as the stationary phase of affinity purification of His-tag proteins. The results showed that a recombinant His-tag protein VP28 in a protein pool was captured by melanin and Ni2+/Fe3+/Zn2+ chelated melanin. Experiments for releasing VP28 were performed only on the melanin and Ni2+-melanin matrices. The result showed that VP28 was quite selectively eluted when applying elution buffer of 250 mM imidazole overnight. The relative efficiency in releasing VP28 of melanin and Ni-melanin matrices roughly compared to Ni-Sepharose were about 38 and 18% respectively. Further optimization of this process may allow higher efficiency in the purification of His-tag proteins.

Viscosity, Degree of Polymerization, Water Uptake, and Water Solubility Studies on Experimental Dichloro-BisGMA-Based Dental Composites

The objective of this work was to investigate the advantages of using dichloro bisphenol A-glycidyl methacrylate (dCl-BisGMA) as a potential matrix for dental resin composites. A series of model composites containing 65 wt% resin (urethane dimethacrylate/triethylene glycol dimethacrylate/BisGMA as 1:3:1) and 35 wt% silanated silica were prepared. Thus, BisGMA was replaced by dCl-BisGMA as 0, 25, 50, and 100 wt% to obtain UTBC0, UTBC25, UTBC50, and UTBC100, respectively. The composites’ rheological properties, degree of double-bond conversion (DC), water sorption (WSP), and water solubility (WSL) were examined. The data revealed a statistically significant reduction in the complex viscosity of composites containing dCl-BisGMA, compared with UTBC0. No significant differences between DCs were detected (p < 0.05). A significant enhancement in the reduction of the dCl-BisGMA composite WSP was also detected, and conversely, WSL was increased. Although the viscosity, DC, and WSP characters were enhanced, a WSL increase is an undesirable development. However, WSL is supposedly caused by cyclization of small flexible chains, which is more likely to occur in the presence of hydrophobic monomers such as dCl-BisGMA and more prone to leaching than are crosslinked networks. We concluded that dCl-BisGMA is a monomer that could potentially be used as an alternative or in combination with traditional monomers, including BisGMA, in resin-based dental composites, and it deserves further investigation.