Oxygen permeability membrane

A large membrane pack of this type will act like an artificial gill, permitting a swimmer to breathe like a fish and remain submerged for much longer periods of time than are possible with scuba equipment. Speculative fiction has man returning to live in the seas, and this type of application may make it possible. Their application in spacecraft is obvious as a part of a continuously recycled air support system. The oxygen permeability of silicone materials is just one example of the selective permeability of plastics. 

Ligeza A, Tikhonov AN, Hyde JS, Subczynski WK. 1998. Oxygen permeability of thylakoid membranes Electron paramagnetic resonance spin labeling study. Biochim Biophys Acta 1365 453. 

Even better results were obtained by Johnson et al. [24] with the Co compounds shown as Fig. 10. These were dissolved in appropriate solvents and immobilized into standard microporous membranes composed of nylon or PTFE. Oxygen permeabilities were as high as 3 x 10 8 sec-cm/(cm2-s-cmHg) with selectivity over nitrogen up to 20, leading to product purity up to 85%. 

Subczynski, W. K., J. S. Hyde, and A. Kusumi. 1989. Oxygen permeability of phosphatidylcholine-cholesterol membranes. Proc. Natl. Acad. Sci. USA 86 4474-4478. 

It is well known that dense ceramic membranes made of the mixture of ionic and electron conductors are permeable to oxygen at elevated temperatures. For example, perovskite-type oxides (e.g., La-Sr-Fe-Co, Sr-Fe-Co, and Ba-Sr-Co-Fe-based mixed oxide systems) are good oxygen-permeable ceramics. Figure 2.11 depicts a conceptual design of an oxygen membrane reactor equipped with an OPM. A detail of the ceramic membrane wall... 

In the early 1990s, Balachandran et al. (51,64,65) of the Argonne National Laboratory, in collaboration with Amoco (now part of BP), investigated the partial oxidation of methane using membrane materials consisting of Sr-Fe-Co-O mixed oxides with the perovskite structure, which have high oxygen permeabilities. In their experiments (51,66), the membrane tubes, which were... 

In a series of papers, Kennedy and co-workers studied the amphiphilic networks and their membrane characteristics. The use of poly(pentamethyl)cyclopentasiloxane)32 as an oxyphilic cross-linker in the novel tricontinuous membranes, consisting of hydrophilic and lipophilic polymers, was reported.466 The presence of polysiloxane brought about high oxygen permeability, which was studied in the water-swollen membranes.467 The use of polysiloxanes as sorbents,468 and as carriers for the receptor molecules in the ion-exchange membranes,469 470 was reviewed. 

Due to these practical aims, membranes with low oxygen permeability have been developed. Some of them are PVA, PVA blends or their derivative membranes, due to the PVA excellent oxygen barrier properties [18],... 

A second class of membranes are described as dense membranes. They may consist of thin plates of metals (Pd and its alloys, Ag and some alloys) or oxides (stabilized zirconia or bismuth oxides, cerates). These membranes are permeable to atomic (for metals) or ionic (for oxides) forms of hydrogen or oxygen and have been studied, especially, in conjunction with chemical... 

Kolosov, E. N., N. I. Starkovskii, S. G. Gul yanova and V. M. Gryaznov. 1988. Oxygen permeability of thin silver membranes Effect of the adsorption of benzene on the oxygen transfer process. Russian J. Phys. Chem. 62(5) 661-663. 

Intrinsic system Apoptosis is initiated due to changes to the mitochondria during which the inner membrane becomes permeable to large molecules, probably as a result of a decrease in the membrane potential. This can result from intracellular damage (e.g. accumulation of Ca ions), lack of oxygen or fuel. This results in release of cytochrome c and other proteins from the mitochondria which stimulate apoptosis. In fact, these apoptotic proteins plus cytochrome c form a complex, the apoptosome, which activates an initiator caspase. 

An elecrochemical device for detecting dissolved oxygen content. The well known Clark electrode consists of a platinum wire tip surrounded by a thin film of electrolyte solution that is shrouded by a plastic membrane. The membrane is permeable to oxygen, but impermeable to... 

One example of membrane reactors is oxidation, in which oxygen from one phase diffuses from one side of an oxygen-permeable membrane to react with a fuel on the other side of the membrane. This avoids a high concentration of O2 on the fuel side, which would be flammable. A catalyst on the fuel side of the membrane oxidizes the fuel to partial oxidation products. One important process using a membrane reactor is the reaction to oxidize methane to form syngas,... 

The resulting electric current is proportional to the oxygen flux to the cathode through the oxygen-permeable membrane that separates the electrode from a culture medium. 

A major advance in the performance of amperometric oxygen sensors has been achieved by placing both the cathode and the anode behind the oxygen-permeable membrane (Fig. 7.4). This sensor is known as the Clark oxygen electrode. 

A schematic diagram of the microbial sensor is illustrated in Figure 1. The sensor consisted of double membranes of which one layer was the bacteria-collagen membrane (thickness 40jam), the other an oxygen permeable Teflon membrane (thickness 27jam), an alkaline electrolyte, a platinum cathode, and a lead anode. 

Glucose sensors II and HI were prepared from the semipermeable membrane of PMSP, poly(1-trimethylsilyl-l-propyne), which has 4 times the oxygen permeability compared with that of FEP membrane. The response properties of sensor H, using a PMSP membrane with 25 Um diameter pinhole, were almost similer to that of the sensor I, so that their calibration curves were not presented in this paper. 

The calibration curves of the sensor IV, which was prepared with a PMSP membrane as an oxygen permeable membrane and an acetyl celulose(AC) membrane as a glucose semipermeable membrane, were shown in Figure 8. This AC membrane was cast by Manjikian s method and treated at a curing temperature of 85°C. The sensor ]V indicated a linear response up to 500 mg/dl of glucose concentration, even under 5 % of oxygen tension, and the output currents were hardly affected by oxygen tension. 

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