Molecular mean field theory for liquid water

Attractive bonding interactions between molecules typically have inherent conservation laws which influence the statistical properties of such systems in terms of corresponding sum rules. We have considered lattice water as an example, and we have enunciated the consequences of the sum rule through a general computational procedure called molecular mean field theory. Fluctuations about the mean field are computed and many of the liquid properties have been deduced and compared with Monte Carlo simulation, molecular dynamics, and experimental results. Large correlation lengths are seen to be a consequence of the sum rule in the liquid phase. Long-range Coulomb interactions are shown to have minor effects on our results.     

Multiple Bioactivities of Manihot esculenta Leaves: UV Filter,Anti-Oxidation,Anti-Melanogenesis,Collagen Synthesis Enhancement,and Anti-Adipogenesis

The cassava root is an important global agro-industrial crop that yields cassava leaf as a left-over co-product of interest for further development as a sustainable resource of health and cosmeceutical active compounds. This work aimed to investigate the cosmeceutical potential and chemical composition of an ethanolic cassava leaf extract (BM). rutin, apigenin, and kaempferol were found to be major constituents via HPLC-DAD UV analysis. Interestingly, the multiple beneficial bioactivities of BM for cosmeceutical applications were manifested in a dose-dependent manner, including anti-oxidation in a 2,2-diphenyl-1-picrylhydrazyl assay, anti-melanogenesis in B16 melanoma cells, collagen synthesis enhancement in human fibroblasts, and anti-adipogenesis in 3T3-L1 adipocytes. Furthermore, the potential of the collagen synthesis enhancement of BM and rutin was significant when compared to ascorbic acid. Additionally, a UV filter property comparable to BEMT with characteristics of board spectral absorption and constant high absorptivity throughout all UV wavelength ranges was exhibited by UV-visible spectrophotometric analysis. In conclusion, the cassava leaf was found to be a potential natural cosmeceutical active agent with multiple cosmeceutical-related bioactivities with respect to a substantial composition of bioactive flavonols. These obtained data will support and encourage the further study and development of cassava leaves as potential economic and sustainable sources of bioactive agents for health and cosmeceutical applications.     

Hydrophobic force,a Casimir-like effect due to hydrogen-bond fluctuations

Hydrophobic force, interfacial tension, and transverse density profile in a confined water system are addressed from first principles of statistical mechanics in a lattice model for water. Using the molecular mean field theory technique we deduce explicit expressions for each of the above mentioned phenomena and show that hydrophobic force is a manifestation of a Casimir-like effect due to hydrogen-bond fluctuations in confined water. It is largely influenced by the long range correlations of orientational fluctuations. Furthermore, the temperature dependence of hydrophobic force between large non-polar surfaces is suggested to be different from that between small solutes. The mechanisms contributing to characteristic behavior in each case are identified. In the case of large surfaces, the prevalence of discrete fluctuation modes in the confinement direction and their entropic contribution to the overall free energy dominate the temperature dependence. Mode discretization is also implicated in the variation of interfacial tension with separation distance between confining surfaces and characteristic density profile of the confined fluid. All the computations are parameter free and compare favorably with results of molecular dynamics simulations and experiments.