The eyebrow and eyelid are important sexually dimorphic and ethnic features of the face. In cosmetic surgery, maintenance of these landmarks is important to obtaining satisfactory results.
Transdermal drug delivery is impeded by the natural barrier of epidermis namely stratum corneum. This limits the route to transport of drugs with a log octanol-water partition coefficient of 1 to 3, molecular weight of less than 500 Da and melting point of less than 200°C. Nanotechnology has received widespread investigation as nanocarriers are deemed to be able to fluidize the stratum corneum as a function of size, shape, surface charges, and hydrophilicity-hydrophobicity balance, while delivering drugs across the skin barrier. This review provides an overview and update on the latest designs of liposomes, ethosomes, transfersomes, niosomes, magnetosomes, oilin- water nanoemulsions, water-in-oil nanoemulsions, bicontinuous nanoemulsions, covalently crosslinked polysaccharide nanoparticles, ionically crosslinked polysaccharide nanoparticles, polyelectrolyte coacervated nanoparticles and hydrophobically modified polysaccharide nanoparticles with respect to their ability to fuse or fluidize lipid/protein/tight junction regimes of skin, and effect changes in skin permeability and drug flux. Universal relationships of nanocarrier size, zeta potential and chemical composition on transdermal permeation characteristics of drugs will be developed and discussed.
We analyse molecular and phenotypic evolution in a group of taxonomically problematic Indomalayan pitvipers, the Trimeresurus sumatranus group. Mitochondrial DNA sequencing provides a well-resolved phylogeny, with each species representing a distinct lineage. Multivariate morphological analysis reveals a high level of phenotypic differentiation, which is congruent between the sexes but does not reflect phylogenetic history. An adaptive explanation for the observed pattern of differentiation is supported by independent contrasts analysis, which shows significant correlations between current ecology and the characters that most account for the variation between taxa, including those that are presently used to identify the species. Reduced precipitation and altitude, and increased temperature, are correlated with higher numbers of scales on the head, body and tail. It is hypothesized that scale number plays an important role in heat and water exchange by influencing the area of exposed of interstitial skin, and that colour pattern variation reflects selection pressures involving camouflage and thermoregulation. Ecological convergence in traits used for classification is found to have important implications for species identification where taxa are distributed over varying environments.
Hydrocortisone (HC), topical glucocorticoid along with hydroxytyrosol (HT), and anti-microbial- and anti-oxidant-loaded chitosan nanoparticles (CSNPs) were prepared in large scale and analyzed for their adverse effects on healthy human skin followed by repeated applications. Ten subjects were randomized to receive test (HC-HT CSNPs) and vehicle samples (aqueous (AQ) cream). They were applied on the arms for 28 days, and transepidermal water loss (TEWL), erythema intensity, and irritation score were measured. Blood samples were analyzed for blood hematology, blood biochemistry, and adrenal cortico-thyroid hormone (ACTH) levels. Skin biopsy was obtained to assess histopathological changes in the skin. HC-HT CSNP AQ cream was stored at 4, 25, and 45 °C for a period of 1 year, and its stability was assessed by monitoring their physical appearances, particle size, and pH. Spherical-shaped NPs were successfully upscaled using spinning-disc technology, with insignificant changes in particle size, zeta potential, and incorporation of drugs as compared to the well-established laboratory method. Particle size of HC-HT CSNPs was skin irritation scoring system and skin hematoxylin and eosin (H&E) staining results. Comparative results of blood hematology, blood biochemistry, and adrenal cortico-thyroid hormone level at day 0 and day 28 were not significant, indicating non-systemic toxicity. In conclusion, HC-HT CSNP AQ cream is safe, well-tolerated, and non-toxic, which may be useful in treating atopic dermatitis.