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A fluorocarbon emulsion with a high solubility for CO2.

A stable emulsion can be prepared by subjecting a mixture of 30% (by volume) FC-80 fluorocarbon; a 0.3-M THAM solution titrated to pH 7.4 with HCl; and 0.04 g F68 Pluronic surfactant per milliliter FC-80 to ultrasonic energy. The emulsion has a density of 1.24 g/ml; and absolute viscosity of 2.4 centipoise; and an approximate fluorocarbon-droplet diameter of 3mu. The approximate CO2 content of the emulsion at partial pressures ranging from 30 to 60 mm Hg is 132 ml (STPD)/liter + (5.5 X PCO2). The O2 content in ml (STPD)/liter equals 0.213 X PO2 (mm Hg).

Carbon Dioxide↗

Alterations of liver and spleen following intravenous infusion of fluorocarbon emulsions.

Mice were injected via tail vein with emulsions of fluorocarbon (FC), an oxygen-carrying compound that has great potential as a blood substitute. Different types of FCs were used. All produced vacuolar changes in hepatocytes, and in reticuloendothelial cells throughout the body. In the liver, occasional inflammatory foci were also observed, but fibrosis was never seen. The vacuolated cells, presumably containing FC, were found as late as one year following a single infusion. However, such cells might also disappear from the liver and spleen. The numbers of affected cells and their rate of disappearance depended on the type of FC, the amount of FC infused, the length of time between infusion and killing. Fluorodecalins, especially PP-5, produced the least amount of change and the most readily reversible change of all FCs tested. The morphologic observations suggest that PP-5 would be more suitable as a blood substitute than the other FCs tested. However, other studies have shown that apparently healthy long-term survival is obtainable even when the infused FC is one that produces extreme vacuolar change in the liver and spleen.

Animals↗

Characteristics of monolayer behavior and multilayer film structures of comb polymers having different kinds of fluorocarbon side-chains.

With comb polymers with different kinds of fluorocarbon side-chains, significant effects of spreading solvents on the monolayers at the air/water interface and the molecular arrangement in the deposited films could be found by the use of trifluoroacetic acid and its mixed solvents with n-hexane, depending on the atoms, fluorine or hydrogen, substituted at the end of the fluorocarbon side-chains. These facts are probably due to intralayer hydrogen bonding cooperating with the carbonyl groups of the long-chain esters. The deposited films of solid substrates were characterized by polarized near-edge X-ray absorption fine structure (NEXAFS) spectroscopy as well as in-plane X-ray diffraction and scanning electron and atomic force microscopy.

Acrylic Resins↗

Plasma lithography--thin-film patterning of polymers by RF plasma polymerization II: Study of differential binding using adsorption probes.

In this study we present methods to physico-chemically modify micropatterned cell culture substrates that were manufactured using plasma lithography to incorporate affinity structures for specific cell binding. The surfaces consist of a pattern of a fluorocarbon plasma polymer with feature sizes between 5 and 100 microm on a background of a non-fouling tetraglyme (tetraethylene glycol dimethyl ether) plasma polymer. The tetraglyme polymer blocks virtually all non-specific binding of proteins, and it is non-adhesive for a fluorocarbon-polyethylene glycol (FC-PEG) surfactant designed to act as a 'hydrophobic anchor' for peptides. The surfactant shows a strong affinity for the fluorocarbon polymer pattern, thus enabling us to form a pattern of the surfactant-conjugated peptide. To verify this, we have synthesized a conjugate between histamine (as a model for a more complex peptide) and a commercially available FC-PEG surfactant. Disuccinimidyl carbonate was used to activate the terminal -OH group of the polyethylene glycol headgroup for the reaction with the amine-containing molecule. Affinity pattern formation can easily be achieved by immersion of the patterned substrates in a solution of the peptide-surfactant conjugate. Time of flight secondary ion mass spectroscopy in the imaging mode was used to verify that the surfactant localizes on the pattern, while the background remains bare. A model protein, bovine serum albumin, showed the same behavior. This suggests that these surfaces can be used for the formation of patterns of cell-adhesive proteins. These substrates will be used to investigate the influence of the cell size and shape of vascular smooth muscle cells on their physiology.

Adsorption↗

Polymer fume fever and other fluorocarbon pyrolysis-related syndromes.

Polymer fume fever usually occurs as a self-limited systemic illness with only minor pulmonary symptoms. Like metal fume fever, constitutional signs and symptoms typically present several hours after initial exposure, often giving rise to a misdiagnosis of viral "flu." Compared to metal fume fever, polymer fume fever has a more varied clinical presentation, the severity of which depends upon the specific conditions of exposure. When higher temperatures and/or longer durations of exposure are involved, significant pulmonary involvement, including radiographic consolidation, is a potential complication. Although a number of industrial outbreaks have implicated the smoking of contaminated cigarettes as a vehicle of exposure, any industrial or household activity in which PTFE is heated above 350-400 degrees C puts nearby workers or residents at risk of illness and is to be avoided without strict industrial hygiene controls.

Animals↗

Optimisation of polymeric surface pre-treatment to prevent bacterial biofilm formation for use in microfluidics.

The production of a microfluidic device for microbial culture has necessitated the development of techniques for the prevention of bacterial adhesion to a range of polymeric substrates including fluoropolymers such as fluorinated ethylene polypropylene, and polyolefins such as low-density polyethylene. Treatment of such materials to increase hydrophilicity reduces the incidence of attachment of Escherichia coli during the first 4 h of cultivation, although no decrease in the number of biofilm initiation sites was detected after 16 h. The incorporation of a mannose analogue to block binding proteins on the F1 binding fimbriae was also investigated. The possibility of ensuring suspension culture of bacterial cells in high surface area to volume ratio nano-vessels is thus facilitated by the correct choice and pre-treatment of materials used in their construction.

Bacterial Adhesion↗

Coherent kinetic control over crystal orientation in macroscopic ensembles of polymer nanorods and nanotubes.

We show that the crystal orientation in polymer nanotubes and nanorods inside porous templates is controlled by the kinetics of nucleation and growth under 2D confinement. Two clear limiting cases are identified: In separated nanostructures, any crystal orientation allowing the growth of lamellar crystals along the pores appears statistically. If a bulklike surface film connects the nanostructures, macroscopic arrays with uniform crystal orientation are obtained, in which the dominant growth direction of the crystals is aligned with the long axes of the pores of the template.

Crystallization↗