A Helical Poly(macromonomer) Consisting of a Polyacetylene Main Chain and Polystyrene Side Chains

2007 ◽  
Vol 28 (10) ◽  
pp. 1115-1121 ◽  
Author(s):  
Wei Zhang ◽  
Masashi Shiotsuki ◽  
Toshio Masuda
Keyword(s):  
Main Chain ◽  
Side Chains

Brushes and lamellar mesophases of comb-shaped (co)polymers: a self-consistent field theory

2020 ◽  
Vol 22 (40) ◽  
pp. 23385-23398
Author(s):  
Ivan V. Mikhailov ◽  
Ekaterina B. Zhulina ◽  
Oleg V. Borisov
Keyword(s):  
Field Theory ◽  
Main Chain ◽  
Side Chains ◽  
Comb Polymers ◽  
Grafting Density ◽  
Consistent Field ◽  
Self Consistent ◽  
Self Consistent Field ◽  
Self Consistent Field Theory

Superimposed distributions of main chain ends in brush of comb polymers with different length and grafting density of side chains.

scholarly journals Rapid model building of α-helices in electron-density maps

2010 ◽  
Vol 66 (3) ◽  
pp. 268-275 ◽  
Author(s):  
Thomas C. Terwilliger
Keyword(s):  
High Resolution ◽  
Electron Density ◽  
Model Building ◽  
Main Chain ◽  
Rapid Identification ◽  
Side Chains ◽  
Low Resolution ◽  
Density Maps ◽  
Experimental Electron Density

A method for the identification of α-helices in electron-density maps at low resolution followed by interpretation at moderate to high resolution is presented. Rapid identification is achieved at low resolution, where α-helices appear as tubes of density. The positioning and direction of the α-helices is obtained at moderate to high resolution, where the positions of side chains can be seen. The method was tested on a set of 42 experimental electron-density maps at resolutions ranging from 1.5 to 3.8 Å. An average of 63% of the α-helical residues in these proteins were built and an average of 76% of the residues built matched helical residues in the refined models of the proteins. The overall average r.m.s.d. between main-chain atoms in the modeled α-helices and the nearest atom with the same name in the refined models of the proteins was 1.3 Å.

Effective dispersants for concentrated, nonaqueous suspensions

1992 ◽  
Vol 7 (10) ◽  
pp. 2884-2893 ◽  
Author(s):  
I. Sushumna ◽  
R.K. Gupta ◽  
E. Ruckenstein
Keyword(s):  
Main Chain ◽  
Side Chain ◽  
Solid Loading ◽  
Head Group ◽  
Side Chains ◽  
Concentrated Suspensions ◽  
Fatty Esters ◽  
Solids Loading ◽  
High Solids Loading ◽  
Order Of Magnitude

With the aim of identifying effective dispersants that would yield stable, high solids loading (≥60 vol.%) suspensions of oxides, carbides, or nitrides in nonaqueous carriers such as paraffinic oils, a number of dispersants were evaluated, using in most cases A16SG grade alumina from Alcoa as the filler. Among those evaluated were some common dispersants, such as menhaden fish oil and oleic acid, and commercial dispersants not commonly used in ceramic processing, such as polymeric fatty esters and petroleum sulfonates. More importantly, a few dispersants were synthesized and evaluated. The latter dispersants contained straight or cyclic (benzenic) side chains located far from the head group on 18 carbon main-chain fatty acid molecules. Among these, the dispersants with a 5–10 carbon side chain or with a benzenic side chain yielded very fluid suspensions (≥60 vol.%) compared to those with long polymeric or oligomeric side chains, or with no side chains, or the commercial dispersants; in some cases, for the same solid loading, the suspension viscosities were an order of magnitude lower with the synthesized side chain dispersants. These results indicate that molecules with an optimum side chain length located sufficiently far from the head group and an optimum backbone (main chain) constitute the most effective dispersants for concentrated suspensions. By combining the advantages provided by wider particle size distributions and by these effective dispersants, suspensions highly concentrated (up to 74 vol.%), and yet processable and “flowing” paste-like have been prepared.

Structures of yeast mnnans containing both α- and β-linked D-mannopyranose units

1969 ◽  
Vol 47 (9) ◽  
pp. 1499-1505 ◽  
Author(s):  
P. A. J. Gorin ◽  
J. F. T. Spencer ◽  
S. S. Bhattacharjee
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Main Chain ◽  
Specific Rotation ◽  
Substantial Proportion ◽  
Side Chains ◽  
Structural Investigations ◽  
Magnetic Resonance Spectra

Several mannans from yeasts give proton magnetic resonance spectra with distinctive H-1 signals at higher field than τ 4.55. A number of these mannans were investigated polarimetrically and each has a specific rotation corresponding to a mixture of α- and β-D-linkages. Four were partially hydrolyzed and shown to have most of the α-linkages in the main chains and the β-linkages in the side chains. Detailed structural investigations showed that the Pichiapastoris mannan probably has an α-(1→6)-D-manno-pyranosyl main-chain substituted in the 2-positions with a substantial proportion of O-α-D-mannopy-ranosyl-(1→2)-O-β-D-mannopyranosyl-(1→2)-O-β-D-mannopyranosyl-(1→2)-O-α-mannopyranosyl side-chains (1). The related mannan from Citeromycesmatritensis has a similar main-chain, which is substituted in the 2-positions by α-D-mannopyranosyl units and β-(1→2)-pyranose-linked D-mannotriosyl and perhaps mannobiosyl side-chains (2).

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