Investigation of the permeability of membranes is most important for biology. The complicated and variable permeability of biological membranes cannot be understood before the simpler conditions in artificial membranes of different qualities have been satisfactorily explained. After M. Traube in 1867 had developed the copper ferrocyanide membrane and Pfeffer published his investigations, the pr...

BACKGROUND Increased intestinal permeability has been reported in one study of adult asthmatics. AIM To determine whether children with asthma have altered intestinal permeability. METHODS Thirty two asthmatic children, and 32 sex and age matched controls were recruited. The dual sugar (lactulose and mannitol) test was used to evaluate intestinal permeability, and the percentage of ingested...

Tryptases are predominantly mast cell-specific serine proteases with pleiotropic biological activities and play a critical role in skin allergic reactions, which are manifested with rapid edema and increases of vascular permeability. The exact mechanisms of mast cell tryptase promoting vascular permeability, however, are unclear and, therefore, we investigated the effect and mechanism of trypta...

Transdermal drug delivery systems are polymeric patches containing dissolved or dispersed drugs that deliver therapeutic agents at a constant rate to the human body. Matrix type transdermal patches were prepared using alprazolam as a model drug and employing the combinations of chitosan-polyvinyl alcohol (CS-PVA) cross linked with Maleic anhydride. The transdermal patches were evaluated for the...

The intentional delivery of Bacillus anthracis spores through mailed letters or packages established the clinical reality of bioterrorism in the United States in autumn 2001. An understanding of the epidemiology, clinical manifestations, and management of the more credible biologic agents is critical to limiting morbidity and mortality from a bioterrorism attack.1-5 Children may be particularly...

The purpose of the present study was to investigate the effect of nanoemulsions as a carrier vehicle of hydrophilic drug for transdermal delivery. The response surface methodology with a mixture design was used to evaluate the effect of ingredient levels of nanoemulsion formulations including cosurfactant (isopropyl alcohol, 20 ∼ 30%), surfactant (mixed of Brij 30 and Brij 35, 20 ∼ 30%), and di...

The influence of voltage on the conductance of toad skin was studied to identify the time course of the activation/deactivation dynamics of voltage-dependent Cl- channels located in the apical membrane of mitochondrion-rich cells in this tissue. Positive apical voltage induced an important conductance inhibition which took a few seconds to fully develop and was instantaneously released by pulse...

Understanding the relevant permeability properties of ultrafiltration membranes is facilitated by using materials and procedures that allow a high degree of control on morphology and chemical composition. Here we present the first study on diffusion permeability through gyroid nanoporous cross-linked 1,2-polybutadiene (1,2-PB) membranes with uniform pores that, if needed, can be rendered hydrop...

This paper proposes a model for the electromagnetic performance of dual air-gap liquid-cooled eddy current retarder (DAL-ECR) considering transient permeability. First, structure and working principle DAL-ECR are introduced. Next, analysis static flux density leakage end effect is established based on piecewise function method magnetic equivalent circuit (MEC). Then, skin field in retarder, an ...

background: central obesity and hyperinsulinaemia of polycystic ovary syndrome (pcos) are associated with chronic sympathetic over activity. objective: to evaluate the autonomic functions and to indicate the superiority, if any, for those functions in the diagnosis of sympathetic over activity in pcos women. materials and methods: sixty-four pcos patients and 40 women served as the control grou...