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Membrane Coating
Published in Sam A. Hout, Manufacturing of Quality Oral Drug Products, 2022
The main difference is in the components used in membrane coating. A primary polymer that is soluble in organic solvents and insoluble in water is used in this application. This membrane needs to maintain its integrity while transiting in watery gastrointestinal tract. The intended release is to provide a higher degree of precision in delivering the drug. To obtain this controlled release action, the semi-permeable membrane acts to control osmotic pressure and desired drug delivery.
Nanobiotechnology Advances in Bioreactors for Biodiesel Production
Published in Madan L. Verma, Nanobiotechnology for Sustainable Bioenergy and Biofuel Production, 2020
Bhaskar Birru, P. Shalini, Madan L. Verma
Osmotic shock facilitates cell disruption through the change in salt concentration which causes the imbalance of osmotic pressure between the exterior and interior of the cell. Cell disruption can be done in two ways, i.e., hyper-osmotic stress and hypo-osmotic stress (Halim et al. 2012). In the case of hyper-osmotic stress, a higher concentration in the exterior of the cell allows the cellular fluids to diffuse outside of the cell which leads to cell wall disruption. On contrary to this, hypo-osmotic stress attributes lower salt concentration in the exterior of the cell leading to the flow of water into the cell which aids for cell disruption (Kim et al. 2013). Hypo-osmotic stress requires a large amount of water for industrial-scale applications. Thus, hyper-osmotic stress is a reliable technique for microalgae cell disruption. Osmotic shock is cost-effective and is an easy process (Prabakaran and Ravindran 2011).
Water Deficits: Development
Published in Yeqiao Wang, Fresh Water and Watersheds, 2020
Kadambot H. M. Siddique, Bramley Helen
The water status of a crop plant is usually defined in terms of its relative water content or water potential. Relative water content is the amount of water in a leaf relative to that at full hydration and standardized by unit dry weight. The net water potential of a plant comprises of two principal components: osmotic pressure and hydrostatic pressure. A gravitational component may also be included, but this is only relevant for tall trees. Osmotic pressure is defined by the concentration of solutes in solution, whereas hydrostatic pressure results from the pressure exerted by water on its surroundings. Within plant cells, water is drawn into the cell due to the concentration of solutes in the cytoplasm and tonoplast. As more water accumulates, the cell volume resists expansion because of the rigidity of cell walls, and a positive hydrostatic pressure develops within the cell called turgor pressure.
A review on multifunctional nanotechnological aspects in modern textile
Published in The Journal of The Textile Institute, 2022
Prashant D. Sarvalkar, Shubham D. Barawkar, Omkar S. Karvekar, Pandurang D. Patil, Saurabh R. Prasad, Kiran Kumar Sharma, Neeraj R. Prasad, Rajiv S. Vhatkar
Antibacterial and fungicidal characteristics can be imparted to textiles using Ag (Aravind et al., 2019), TiO2 (Zhang et al., 2019), and ZnO (Singh et al., 2012) NPs. Because Ag NPs have a wide surface area, they are more likely to come into contact with bacteria and fungi. Ag NPs' antiseptic method involves their interacting with proteins in these organisms, impairing cellular function and reducing cell growth. They also lower respiration and substrate transport into the cell membrane, decreasing the activity of the electron transfer system's basal metabolism. Ag NPs bind to the cell wall and membrane when they come into contact with moisture or bacteria. While Ag NPs are innocuous in their metallic state, they ionize when exposed to moisture. The Ag+ ions are reactive and diffuse into the cytoplasm through the cell wall and membrane. To structurally modify the cell wall, Ag+ ions attach to sulphur-containing proteins on the cell membrane. Because of the variations in osmotic pressure, the cellular components are released into the extracellular fluid. Additionally, Ag+ ions attach to phosphate-containing proteins, condensing DNA and causing cell death through a reaction with thiol group proteins. They also stop enzymes from working and prevent the cell from producing ATP. The growth and proliferation of bacteria and fungi that cause odour and itching are slowed by Ag NPs. Ag NPs, for example, can be used to inhibit germs and fungi from growing on socks.
Consolidation and creep phenomena in a sand-bentonite mixture under controlled suctions
Published in Geomechanics and Geoengineering, 2022
Mohsen Ajdari, Ebrahim Niknam, Hossein Bahmyari, Zahra Esfandiari
Osmotic pressure is referred to the minimum force needed to apply to a fluid in solutes with different concentrations and causes the fluid to move through a semi-permeable membrane to a higher concentration. Zur (1966), was one of the first researchers who used this method in soil science. In his research, different osmotic pressure (chemical potential) was used by increasing salt concentration in the solution. Polyethylene glycol (PEG) solution was used to apply suction in this study. PEG solution is an organic polymer formed by repeating carbon units and hydrogen atoms and with thousands of repetitions, forms a long chain of high molecular weight molecules. In the osmotic suction method, the semi-permeable membrane is placed between the large PEG molecules and the unsaturated soil. This membrane prevents the upward movement of the PEG molecules towards the sample but allows water to transfer. The amount of transferred water is dependent on the macromolecular concentration of the solution and soil suction. A reliable method for measuring the concentration of the PEG solution is using manual refractometer that provides soluble Brix amount in solution. Delage et al. (1992) proposed a method for calibrating the percentage of Brix and concentration of the PEG in water. Boso et al. (2005) presented the suction versus the concentration of the PEG solution which was valid at 20°C.
Polyethylene glycol and membrane processes applied to suction control in geotechnical osmotic testing
Published in International Journal of Geotechnical Engineering, 2022
Rick Vandoorne, Petrus J. Gräbe, Gerhard Heymann
In Figure 1(a) an aqueous solution of PEG is separated from pure water by a selectively permeable membrane in a u-tube manometer. The membrane allows the passage of water (solvent) molecules and not the dissolved PEG (solute) molecules. Osmotic pressure () arises due to the presence of a solute and is a measure of the reduction in the chemical water potential of the solution with reference to the chemical potential of pure water at the same temperature and pressure. The total chemical water potential is lowered by the participation of water molecules in the solvation of the solute. The difference in water potential drives the movement of pure water through the membrane towards the solution side.