Silicone is already widely used in biomedical applications thanks to its outstanding properties. Now additive manufacturing (AM) of silicone can achieve submillimeter details and offered by SpectroPlast AG as a service. AM particularly interesting for designs with complex internal structures such bioreactors or oxygenators where oxygen permeability important. Therefore, the additively manufactu...

Protons and sodium ions are the only used coupling ions in energy transduction in Bacteria and Archaea. At their growth temperature, the permeability of the cytoplasmic membrane of thermophilic bacteria to protons is high as compared to sodium ions. In some thermophiles, therefore, sodium is the sole energy coupling ion. Comparison of the protonand sodium permeability of the membranes of variet...

A hydrodynamic permeability of membranes built up by porous cylindrical or spherical particles with impermeable core is investigated. Different versions of a cell method are used to calculate the hydrodynamic permeability of the membranes. Four known boundary conditions, namely, Happel’s, Kuwabara’s, Kvashnin’s and Cunningham/Mehta-Morse’s, are considered on the outer surface of the cell. Compa...

The permeability of the septa of the earthworm in the median axon has been calculated for the anions fluorescein and its halogen derivatives. The values ranged from 5.4 X 10(-5) to 4 X 10(-6) cm/s. Previously, the septa had been shown to contain nexuses. By using freeze-fracture material, the surface area of nexus on the septal membranes was determined to be 4.5%, very similar to the percentage...

The pineal gland, an endocrine organ in the brain, synthesizes and secretes the circulating night hormone melatonin throughout the night. The literature states that this hormone is secreted by simple diffusion across the pinealocyte plasma membrane, but a direct quantitative measurement of membrane permeability has not been made. Experiments were designed to compare the cell membrane permeabili...

This is a review. Non-electrolytic compounds typically cross cell membranes by passive diffusion. The rate of permeation is dependent on the chemical properties of the solute and the composition of the lipid bilayer membrane. Predicting the permeability coefficient of a solute is important in pharmaceutical chemistry and toxicology. Molecular simulation has proven to be a valuable tool for mode...

A critical event in ischemia-based cell death is the opening of the mitochondrial permeability transition pore (MPTP). However, the molecular identity of the components of the MPTP remains unknown. Here, we determined that the Bcl-2 family members Bax and Bak, which are central regulators of apoptotic cell death, are also required for mitochondrial pore-dependent necrotic cell death by facilita...

Standard metabolic rate is 7-fold greater in the rat (a typical mammal) than in the bearded dragon, Amphibolurus vitticeps (a reptile with the same body mass and temperature). Rat hepatocytes respire 4-fold faster than do hepatocytes from the lizard. The inner membrane of isolated rat liver mitochondrial has a proton permeability that is 4-5-fold greater than the proton permeability of the liza...

Membrane filtration, especially based on the size exclusion phenomenon, has long been established due to its abilities to addressing the growing demands of the clean water of the world’s population. However, widespread applications of the membranes face several challenges including chemical vulnerability, thermal deterioration, and biological degradation of the membranes that transpire while re...

The main aim of this work is to develop a model of hydrogen sulfide (H2S) separation from natural gas by using membrane separation technology. The model is developed by incorporating three diffusion mechanisms which are Knudsen, viscous and surface diffusion towards membrane selectivity and permeability. The findings from the simulation result shows that the permeability of the gas is dependent...