Cellulose-incorporated systems

It is convenient to distinguish between three types of water in the cellulose-water system. The first type of water is directly coupled to the cellulose lattice and gives rise to a very broad contribution to the proton band intensity deriving from the cellulose chains. Since this water signal is incorporated in the broad cellulose signal it can be characterized as invisible water, the presence of which... 

Tape >System of Analysis. A tape system which is used widely for analysis in the Pediatric Laboratory is a system whose principle was developed by the author. A reagent is placed on a paper tape. The paper is covered with a membrane, such as cellophane, cellulose nitrate or cellulose acetate, porous to low molecular weight substances. Finally, the serum is placed above the porous membrane, so that diffusion of the components of serum take place and a stain is produced on the paper (60). This principle has been incorporated for example, with glucose oxidase, in the conmercially available Dextro-Sticks. In addition, a similar principle is being applied by some for the analysis of components in urine (Ames Co., South Bend, Indiana). 

In view of the immense commercial importance of phthalocyanines as pigments, it is perhaps surprising that only a few are of importance as textile dyes. This is primarily due to the size of the molecules they are too large to allow penetration into many fibres, especially the synthetic fibres polyester and polyacrylonitrile. An example of a phthalocyanine dye which may be used to dye cellulosic substrates such as cotton and paper is C. I. Direct Blue 86 (96), a disulfonated copper phthalocyanine. In addition, a few blue reactive dyes for cotton incorporate the copper phthalocyanine system as the chromophoric unit (Chapter 8). 

Hassid and coworkers293 reported that this mung-bean enzyme-system catalyzes the incorporation of D-glucose from GDP-D-glucose into a polysaccharide having the characteristics of cellulose and that, in the presence of GDP-D-mannose, this incorporation was stimulated. The same enzyme-system, when provided with GDP-D-mannose as the sole substrate, catalyzed the incorporation of GDP-D-mannose into a glucoman-... 

The situation is complicated by the fact that the efficiency of cellulose synthesis in the cell-free system is low, and the same enzyme preparation catalyzes the incorporation of D-glucosyl groups from UDP-Glc into alkali-soluble (1 - 2)-/3-D-glucans.370 A similar process was reported to occur with a membrane preparation of Rhizobium meliloti,371... 

The main problem in this approach is the very low permeability of mevalonic acid to membranes, resulting in very low incorporation. Positive results have been obtained by the use of cell-free systems incubated with [14C]-mevalonic acid,26,27 [14C]isopentenyl diphosphate,28 or [32P]orthophos-phate.29 Incubation of these radioactive lipids with glycosyl nucleotides labelled in the glycosyl group with a different isotope, followed by extraction and cochromatography in different solvent systems, may indicate that both compounds are present in the same molecule. When the lipid moiety becomes labelled from mevalonic acid or isopentenyl diphosphate, chromatography on DEAE-cellulose columns should be performed, in order to avoid confusion with steryl glycosides. 

It is possible to avoid incorporation of homopolynucleotide by using ternary complexes between polynucleotide, SPG, and polycation. It was recently demonstrated that such ternary complexes can be prepared with PEI and cationic cellulose (quatemized nitrogen is a charged functional group in cationic cellulose) [55]. However, this kind of approach is a step away from the non-cationic nature of schizophyllan-based delivery systems and will not be discussed here. 

The electrophoretic separation technique is based on the principle that, under the influence of an applied potential field, different species in solution will migrate at different velocities from one another. When an external electric field is applied to a solution of charged species, each ion moves toward the electrode of opposite charge. The velocities of the migrating species depend not only on the electric field, but also on the shapes of the species and their environmment. Historically, electrophoresis has been performed on a support medium such as a semisolid slab gel or in nongel support media such as paper or cellulose acetate. The support media provide the physical support and mechanical stability for the fluidic buffer system. Capillary electrophoresis (CE) has emerged as an alternative form of electrophoresis, where the capillary wall provides the mechanical stability for the carrier electrolyte. Capillary electrophoresis is the collective term which incorporates all of the electrophoretic modes that are performed within a capillary. 

Adhesives. Poly(vinyl alcohol) is used as a component in a wide variety of general-purpose adhesives to bond cellulosic materials, such as paper and paperboard, wood textiles, some metal foils, and porous ceramic surfaces, to each other. It is also an effective binder for pigments and other finely divided powders. Both fully and partially hydrolyzed grades are used. Sensitivity to water increases with decreasing degree of hydrolysis and the addition of plasticizer. Poly(vinyl alcohol) in many applications is employed as an additive to other polymer systems to improve the cohesive strength, film flexibility, moisture resistance, and other properties. It is incorporated into a wide variety of adhesives through its use as a protective colloid in emulsion p olymerization. 

In terms of paper conservation, this work is of value since it is an attempt to determine (i) if UV and EB grafting times for cellulose copolymerization can be shortened significantly by the inclusion of appropriate additives and (ii) if such a process is capable of incorporating into cellulose properties required for preservation, particularly wet and dry strength and flexibility. These studies also should indicate the feasibility of extrapolating data from the present solvent grafting systems to processes based on solvent-free, rapid-cure UV and electron beam (EB) which are the ideal polymerization conditions for preservation applications. 

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