A confined liquid with dispersed neutral particles is theoretically studied when the limiting surfaces present different dynamics for the adsorption-desorption phenomena. The investigation considers different non-singular kernels in the kinetic equations at the walls, where the suitable choice of the kernel can account for the relative importance of physisorption or chemisorption. We find that even a small difference in the adsorption-desorption rate of one surface (relative to the other) can drastically affect the behavior of the whole system. The surface and bulk densities and the dispersion are calculated when several scenarios are considered and anomalous-like behaviors are found. The approach described here is closely related to experimental situations, and can be applied in several contexts such as dielectric relaxation, diffusion-controlled relaxation in liquids, liquid crystals, and amorphous polymers.
Cholesteric liquid crystals are frequently produced by the addition of chiral dopants to achiral nematic hosts. We report here the synthesis and performance of chiral dopants obtained from bio-betulin produced by a fermentation process. An important aspect of this work is to point out that the fermentation process used to obtain the starting materials is much easier and cheaper when carried out in large volumes than isolating it from the natural product. The performance of the dopants obtained from bio-betulin is indistinguishable from those obtained from commercially available synthetic betulin.
ABSTRACT. The cell membrane is one of the most important structures of living organisms. This is due to the many functions attributed to it such as permeable selectivity, protection, anchoring to the cytoskeleton and so many others. Any change in the shape of the cell membrane may affect directly the properties and abilities. In this article, we study how defects in the liquid crystalline organization of a membrane can change its shape. For performing this, we consider a membrane with orientational order, i.e., a nematic membrane, which can happen in biological membranes, nematic films and other systems and study how a defect in this order can change the shape of the membrane when the bending rigidity is considered. We find that depending on the ratio of rigidity and elastic constant, buckling of this membrane may happens and turn it into pseudo-spheres.Keywords: +1 defects, nematic liquid crystals, bending rigidity, buckle.
Mudança de morfologia em membranas nemáticas induzida por defeitos
RESUMO.A membrana celular é uma das estruturas mais importantes dos seres vivos. Isto se deve aos vários fatores atribuídos a ela como permeabilidade seletiva, proteção, ancoramento ao citoesqueleto e vários outros. Qualquer mudança no formato da membrana celular pode afetar diretamente suas propriedades e habilidades. Neste artigo, estudamos como defeitos na organização liquido cristalina de uma membrana pode mudar o seu formato. Isto é feito considerando-se uma membrana com ordem orientacional, isto é, uma membrana nemática, o que pode ocorrer em membranas biológicas, filmes nemáticos e outros sistemas e estudamos como defeitos nesta ordem podem mudar o formato da membrana quando a rigidez da membrana é levada em conta. É encontrado que dependendo da razão entre rigidez e constante elástica, curvaturas desta membrana podem ocorrer levando a formatos conhecidos como pseudo-esferas.Palavras-chave: defeitos +1, cristais líquidos nemáticos, rigidez, curvatura.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.