Branched Polymers
Mostrando 13-24 de 27 artigos, teses e dissertações.
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13. Optimal transfection with the HK polymer depends on its degree of branching and the pH of endocytic vesicles
We have recently reported that liposomes in combination with histidine (HK)-containing polymers enhanced the expression of luciferase in transfected cells. In transformed or malignant cell lines, branched HK polymers (combined with liposome carriers) were significantly more effective than the linear HK polymer in stimulating gene expression. In the current s
Oxford University Press.
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14. Self-similar self-avoiding structures: Models for polymers
The hierarchy of m,n-self-similar self-avoiding structures on a lattice is introduced as a model for linear and branched polymers. The self-similarity condition permits exact solutions that use a generating-function renormalization procedure with full accounting for volume exclusion. Illustrative results are given for the 1,2-linear-chain model and for the 1
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15. Trapping of branched DNA in microfabricated structures.
We have observed electrostatic trapping of tribranched DNA molecules undergoing electrophoresis in a microfabricated pseudo-two-dimensional array of posts. Trapping occurs in a unique transport regimen in which the electrophoretic mobility is extremely sensitive to polymer topology. The arrest of branched polymers is explained by considering their center-of-
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16. Modified branched peptides with a histidine-rich tail enhance in vitro gene transfection
Successful gene therapy depends on the development of efficient, non-toxic gene delivery systems. To accomplish this objective, our laboratory has focused on solid-phase synthesized peptide carriers, in which the amino acid sequence can be varied precisely to augment intracellular DNA transport. We previously determined that linear and branched co-polymers o
Oxford University Press.
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17. Changes in Cell Wall Polysaccharides of Green Bean Pods during Development
The changes in cell wall polysaccharides and selected cell wall-modifying enzymes were studied during the development of green bean (Phaseolus vulgaris L.) pods. An overall increase of cell wall material on a dry-weight basis was observed during pod development. Major changes were detected in the pectic polymers. Young, exponentially growing cell walls conta
American Society of Plant Physiologists.
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18. Phase Separation of Plant Cell Wall Polysaccharides and Its Implications for Cell Wall Assembly.
Concentrated binary mixtures of polymers in solution commonly exhibit immiscibility, resolving into two separate phases each of which is enriched in one polymer. The plant cell wall is a concentrated polymer assembly, and phase separation of the constituent polymers could make an important contribution to its structural organization and functional properties
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19. Physical Properties and Chemical Composition of β-Glucans from Fleshy Fungi
Physical properties and chemical structure of two related polysaccharides produced fermentatively by Plectania occidentalis NRRL 3137 and by Helotium sp. NRRL 3129 were studied. Both polymers were readily recovered as amorphous gels by precipitation from culture liquors with two parts of ethyl alcohol or methanol. Dried polymeric material was redissolved in
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20. Analyses of Glucans from Cariogenic and Mutant Streptococcus mutans
The extracellular, water-soluble and cell-associated, 1 N NaOH-soluble glucans from cariogenic Streptococcus mutans 6715-13 “wild type” (WT) and glucan synthesis-defective mutants with diminished virulence have been quantitatively and qualitatively analyzed by methylation analysis and gel chromatography. The mutants synthesized more of a highly branched
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21. Influence of the Molecular Weight of Bioreducible Oligoethylenimine Conjugates on the Polyplex Transfection Properties
The purpose of the present study was to investigate the influence of molecular weights on the chemical, biophysical, and biological properties of bioreducible oligoethylenimine conjugates. The cationic conjugates were synthesized by polyaddition between branched oligoethylenimine 800 Da (OEI) and the disulfide bond containing N,N′-cystamine bisacrylamide
Springer US.
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22. Molecular Characterization of a Novel Glucosyltransferase from Lactobacillus reuteri Strain 121 Synthesizing a Unique, Highly Branched Glucan with α-(1→4) and α-(1→6) Glucosidic Bonds
Lactobacillus reuteri strain 121 produces a unique, highly branched, soluble glucan in which the majority of the linkages are of the α-(1→4) glucosidic type. The glucan also contains α-(1→6)-linked glucosyl units and 4,6-disubstituted α-glucosyl units at the branching points. Using degenerate primers, based on the amino acid sequences of conserved reg
American Society for Microbiology.
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23. Polyester Biosynthesis Characteristics of Pseudomonas citronellolis Grown on Various Carbon Sources, Including 3-Methyl-Branched Substrates
Forty-two different carbon sources were tested for the polyester synthesis of a citronellol-utilizing bacterium, Pseudomonas citronellolis (ATCC 13674). These included linear C2 to C10 monocarboxylic acids, C3 to C10 dicarboxylic acids, saccharides, α,ω-diols, hydrocarbons, and 3-methyl-branched substrates such as 3,7-dimethyl-6-octen-1-ol (citronellol), 3
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24. Physiological and Chemical Investigations into Microbial Degradation of Synthetic Poly(cis-1,4-isoprene)
Streptomyces coelicolor 1A and Pseudomonas citronellolis were able to degrade synthetic high-molecular-weight poly(cis-1,4-isoprene) and vulcanized natural rubber. Growth on the polymers was poor but significantly greater than that of the nondegrading strain Streptomyces lividans 1326 (control). Measurement of the molecular weight distribution of the polymer
American Society for Microbiology.