Cellular poly

Poly(vinylchloride). Cellular poly(vinyl chloride) can be produced from several expandable formulations as well as by decompression techniques. Rigid or flexible products can be made depending on the amount and type of plasticizer used (43). 

Poly(vinylchloride). Cellular poly(vinyl chloride) is prepared by many methods (108), some of which utili2e decompression processes. In all reported processes the stabili2ation process used for thermoplastics is to cool the cellular state to a temperature below its second-order transition temperature before the resia can flow and cause coUapse of the foam. 

Extmsion processes have been used to produce high and low density flexible cellular poly(vinyl chloride). A decomposable blowiag ageat is usually bleaded with the compouad prior to extmsioa. The compouaded resia is thea fed to an extmder where it is melted under pressure and forced out of an orifice iato the atmosphere. After extmsion iato the desired shape, the cellular material is cooled to stabili2e it and is removed by a belt. 

Fig. 3 A, B. A Time courses of cellular poly(3HB) content during the accumulation phase plotted for various specific poly(3HB) formation rates. B Amount of poly(3HB) as a multiple of the residual biomass at different poly(3HB) contents... 

When comparing fed-batch operated cultures it can be seen that the main difference between poly(3HB) and poly(3HAMCL) production that affect the process parameters is the lower cellular poly(3HAMCL) content, compared to the cellular poly(3HB) content. Not surprisingly, it has been reported that a low poly(3HAMCL) content decreases the productivity and yield and increases the costs for downstream processing and waste disposal [102]. 

Modification of poly(carbodiimide) foams with polyols afford hybride foams containing urethane sections. However, the thermal stabilities of the poly (urethane carbodiimide) foams are lower. Using isocyanate trimerization catalysts, such as l,3,5-tris(3-dimethylaminopropyl)hexahydro-s-triazine, in combination with the phospholene oxide catalyst gives poly(isocyanurate carbodiimide) foams with improved high temperature properties. The cellular poly(carbodiimide) foams derived from PMDI incorporate six-membered ring structures in their network polymer structure. ... 

Cellular poly(carbodiimides) derived from polymeric isocyanate (PMDI) can be continuously produced using a phospholene oxide catalyst. As the component temperature is increased from 25 °C to 80 °C at a constant catalyst level, foam densities decrease with increasing component temperatures, with an expected corresponding decrease in compressive strength. The foam friability also decreases with increasing component temperature. 

Cellular polymers, especially polystyrene and polyurethane, are also widely used for pipe and vessel insulation. The use of cellular rubber and cellular poly(vinyl chloride) in insulation for small pipes is attributed to their ease of application, combustion properties, and low thermal conductivity. 

Cellular plastics, mainly polystyrene, are used for display and novelty pieces because of ease of fabrication, light weight, attractive appearance, and low cost. Phenolic foam is used in floral displays, where it can hold large amounts of water for long periods. Polyurethane and polystyrene foams are also used in other floral applications. Cellular poly(vinyl chloride) is used in toys and athletic goods. 

In order to illustrate the different types of the function f(s) that can be obtained from the same cellular polymer but at different packing factors (see Sect. 4), the authors prepared some cellular poly(vinyl alcohol)polymers foamed with nitrogen. The... 

PPE exhibits a high dielectric strength. Thus, it can be used as a polymeric electret. Neat PPE shows an excellent charge storage behavior, which is better than that of cellular poly(propylene) and polyfether imide). 

Additional support for a link between longevity and poly(ADP-ribo l)ation came from a pharmacolo cal approach We could show that treatment of SV40-transft>rmed embryonic hamster cell cultures with low-concentrations of L-sel iline (deprenyl), an anti-Parkinson drug that induces life-span extension in normal laboratory animals, potentiated the cellular poly(ADP-ribosyl)ation response to DNA-damaging tteatment. ... 

Cottet F, Blanche H, Vetasdonck P et al. New polymorphisms in the human poly(ADP-ribose) polymerase-1 coding sequence Lack of association with longevity or with increased cellular poly(ADP-ribosyl)ation capacity. J Mol Med 2000 78(8) 431-440. 

Brabeck C, Pfeiffer R, Leake A et al. Usel iline potendates cellular poly (ADP-ribose) formation induced by DNA damage. J Pharmacol Exp Ther 2003 306 973-979. 

The basic approach involved preparation of total cellular poly(A)-rich RNA using phenol/chloroform and affinity chromatography on... 

The finding that most eukaryotic mRNAs have a poly(A) sequence at their 3 -terminus (See ref. 25 for a review) simplified the isolation procedure of mRNA considerably, since it could be bound to poly (u) or oligo dT embedded into filters or columns and recovered free of non-poly (A)-containing RNA such as rRNA. Using this technique the fate of pre-labeled cellular poly(A)-containing polysomal mRNA could easily be followed in uninfected and mengovirus infected L-cells (9). The pre-labeled cellular mRNA was found to associate with polysomes for up to at least 5 hours after infection, even though by this time there was considerable inhibition of cellular protein synthesis (Table 1). 

Fig. 1. Effect of inhibitors on cellular poly(ADP-ribose) levels in MNNG-treated HL60 cells. HL60 cells were cultured in RPMl 1640 medium buffered with 20 mM Hepes, pH 7.8 and supplemented with 10% horse serum, penicillin (50 units/ml), streptomycin (50 pg/ml) and 7.5% sodium bicarbonate at 37° C. HL60 cells were treated with 0.5 mM MNNG dissolved in DMSO. Treatments were stopped at different times of incubation by treating the cells with 10 ml 20% TCA. The poly(ADP-ribose) content was determined in the TCA pellet according to Jacobson et al. (8). Control cells contained 4.1 pmol of eRAdo/10 cells. These values remained constant in cells incubated at 30°C without the carcinogen. Reprinted with permission from ref. 9.

Fig. 2. Cellular poly(ADP-ribose) levels of HL60 cells grown in the absence and presence of nicotmamide prior to MNNG treatment for 10 min at 30 C. Cells were cultured, treated and extracted as in the legend to Fig. 1. A Cells in 3 day culture medium. B Fresh medium 24 hr prior to experiment. C Fresh medium supplemented with 2mM nicotinamide 24 hr prior to experiment.

Extrusion processes have been used to produce high and low density flexible cellular poly(vinyl chloride). A decomposable blowing agent is usually blended... 

Injection molding of high density cellular poly(vinyl chloride) can be accomplished in a manner similar to extrusion except that the extrudate is fed for cooling into a mold rather than being maintained at the imiform extrusion cross-section. 

Applications. Flexible cellular poly(vinyl chloride) was developed as a comfort-cushioning material with compression-deflection behavior similar to latex rubber foam, and with the added feature of flame retardancy (37). It has a... 

A recombinant strain of E. coli was used in the development of a quantitative spectroscopic method for the measurement of poly(3HB) content in the cell (Kansiz et al. 2000). Fourier transform infrared (FTIR) spectroscopy and multivariative statistical methods were performed to determine the cellular poly (3HB) content, and a correlation coefficient of 0.988, with a standard error of 1.49 % poly(3HB), was obtained between the measured and the predicted values. The spectroscopic method circumvented the need to use solvents to extract the PHA before quantitative measurements. 

Mihai, M., M. A. Huneault, and B. D. Favis. 2009. Crystallinity development in cellular poly (lactic acid) in the presence of supercritical carbon dioxide. J Appl Polym Sci 113 2920-32. 

Mandal S, Mandal A, Johansson HE et al (2013) Depletion of cellular poly amines, spermidine and spermine, causes a total arrest in translation and growth in mammalian cells. Proc Natl Acad... 

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