Polyethylene glycol treatment, methods

Other methods of forcing cell fusion include polyethylene glycol treatment of plant membranes and a process called electroporation, in which pulses of electricity cause small pores... 

The anionic method of polymerization is most useful for the synthesis of low molecular weight hydroxy-terminated oligomers and polymers that are to be further processed. For example, the treatment of hydroxy-terminated oligomers with isocyanates has been used to obtain polyester-urethanes (9,20), while triblock copolymers (PCL-PEG-PCL) are prepared by initiating the polymerization of e-caprolactone with the disodium alcoholate from polyethylene glycol (26). 

The ethyl acetate solution of organic species from the pre-treatment scheme shown in Figure 1 is suitable for analysis by this method. In order to cover the range of common explosives several chromatography columns with different types of stationary phase are required to allow for difierent polarities and volatihties. Dimethylsiloxane, phenyl-modified dimethylsiloxane, cyanopropyl- phenyl- vinyl-modified dimethylsiloxane, and polyethylene glycol have been found to represent a useful set of stationary phases. Carefully optimised temperature programming is also needed to obtain the requisite resolution and avoid interferences [19, 20]. 

Environmental applications of HRP include immunoassays for pesticide detection and the development of methods for waste water treatment and detoxification. Examples of the latter include removal of aromatic amines and phenols from waste water (280-282), and phenols from coal-conversion waters (283). A method for the removal of chlorinated phenols from waste water using immobilised HRP has been reported (284). Additives such as polyethylene glycol can increase the efficiency of peroxidase-catalyzed polymerization and precipitation of substituted phenols and amines in waste or drinking water (285). The enzyme can also be used in biobleaching reactions, for example, in the decolorization of bleach plant effluent (286). 

Second, dead lambs were smeared with neatsfoot oil (an oil obtained by boiling feet and leg bones of cattle), left with the mother for 2-18 hours and then substituted by neatsfoot oil-treated foster lambs. Here 91% were accepted. The best acceptance rate (100%), however, was achieved by draping the skin of the dead lamb over the alien one. This is the method of choice because it is not only most effective but also saves labor as no treatment is necessaiy (Alexander eta/., 1987). Ewes accept alien lambs if they are rubbed with non-polar oils such as white soft paraffin or liquid paraffin. Polar materials such as polyethylene glycol, glycerol silicone, or diisooctyl phthalate have no effect. Ewes appear to use non-polar volatiles for discrimination (Alexander etal., 1989). 

Treatment of wood with polyethylene glycol (PEG) is the most commonly used method to impart dimensional stability to wood. PEG in a water solution can be used to permeate the lumens and penetrate the cell wall. A 30-50 percent solution of PEG in water generally is used on green wood no pressure is required. Treatment times are adjusted so that a uniform uptake of 25-30 percent of PEG is achieved, based on the dry weight of the wood temperatures range from 21 to 60°C. The wood may require weeks of soaking, depending on species, density, and thickness. After treatment, the wood is dried in a well-ventilated space, preferably heated. 

Synthesis from polyethylene glycol dibromides. Treatment of a poly (ethylene glycol) dibromide with Ba(OH)2 8H2O as a source of OH" and Ba followed by pyrolysis results in a crown ether. The Ba ion acts as a template. The present method requires only one building block (with one less oxygen than the crown ether formed). Highest yields (50%) are obtained with 18-crown-6. ... 

Inverse gas chromatography (IGC) is used for the determination of the surface energy characteristics of silicas before and after modification by heat treatment or by grafting onto their surface alkyl, polyethylene glycol) and alcohol chains. Because of its high sensitivity, IGC reveals the nature of the grafted molecules, which may then be confirmed by independent methods. 

A chemical destruction method that has been used for the treatment of PCBs in contaminated dielectric liquids or soil is based on the reaction of a polyethylene glycol/potassium hydroxide mixture with PCBs (De Filippis et al. 1997). This method can be used successfully for the destruction of higher chlorinated PCBs with an efficiency of >99%, but was found to be unsuitable for the treatment of di- and trichlorobiphenyls due to low destruction efficiencies (Sabata et al. 1993). Irradiation of PCBs in isooctane and transformer oil by y-radiation resulted in degradation of PCBs to less chlorinated PCBs and PCB-solvent adducts (Arbon et al. 1996). Supercritical fluid technology has shown promise as a method for extraction of PCBs from soils, coupled with supercritical water oxidation of the extracted PCBs (Tavlarides 1993,1998a). Hofelt and Shea (1997) demonstrated the use of semipermeable membrane devices to accumulate PCBs from New Bedford Harbor, Massachusetts water. Another method showing... 

Synthesis. A new general synthesis of crown ethers involves treatment of polyethylene glycols with sulfonyl chlorides in the presence of NaOH or KOH, which serves as the template. For example, 15-crown-5 was obtained in 50% isolated yield by this method (equation I). 18-Crown-6 is prepared in this way in 757 yield. Substituted crown ethers have also been prepared by this method. 

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