Effect of Polymerization Degree on Building-up Helical Structure of Oligo(L-lactic acid)

Tatsumi Kimura; Takashi Fukuda; Satoru Shimada; Hiro Matsuda

doi:10.1246/cl.2004.608

Effect of polymerization degree of oligogalacturonates and D-galacturonans on their circular dichroic spectra

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19790167 ◽

1979 ◽

Vol 44 (1) ◽

pp. 167-173 ◽

Cited By ~ 4

Author(s):

Slavomír Bystrický ◽

Rudolf Kohn ◽

Tibor Sticzay

Keyword(s):

Physicochemical Properties ◽

Aqueous Solutions ◽

Helical Structure ◽

Monomeric Unit ◽

Polymerization Degree ◽

Cd Spectra ◽

Circular Dichroic

The CD spectra of aqueous solutions of homopolymeric sodium oligogalacturonates and D-galacturonans of polymerization degree n = 1-64, as well as lower calcium oligogalacturonates (n = 1-5) were measured. Chiroptic properties were correlated with the polymerization degree in terms of optical superposition of monomeric unit increments. Interpretation of obtained data, respecting further physicochemical properties entitles to conclude that the conformation of macromolecules of D-galacturonan in solution is close to helical structure.

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Synthesis and Characterization of Poly (L-Lactic acid) Containing the Azobenzene Mesogens

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.181-182.185 ◽

2011 ◽

Vol 181-182 ◽

pp. 185-188

Author(s):

Run Tao Dong ◽

Qing Bin Xue ◽

Ling Min Sun ◽

Quan Xuan Zhang

Keyword(s):

Lactic Acid ◽

Optical Rotation ◽

Gel Permeation Chromatography ◽

Helical Structure ◽

Feed Ratio ◽

Scanning Calorimetry ◽

Molecular Weights ◽

H Nmr ◽

Azobenzene Mesogens

A series of azobenzene containing group Poly (L-lactic acid) (PLLA) were synthesized by Ring-Opening Polymerization of L-lactide (L-LA) catalysted by Sn (Oct)2initiated by alcohol-OH containing the azobenzene chromophores. Their molecular weights were well controlled by the feed ratio as characterized by Gel Permeation Chromatography (GPC) and1H NMR Spectrometry and agreed well with theoretical values. The thermal properties and liquid crystal phases were investigated by Differential Scanning Calorimetry (DSC), polarized optical microscopy (POM) and X-ray Diffraction (XRS) measurements. Cis-trans photoisomerization behavior of the polymers in the solutions and the films were studied with UV irradiation. By the Circular Dichroism Spectroscopy (CD) characterization of the solutions and films of the polymer, the PLLA segments show huge optical rotation power in helical structure.

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Demonstration of Retinal Glycogen with Silver Methenamine

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100066875 ◽

1971 ◽

Vol 29 ◽

pp. 564-565

Author(s):

A. W. Sedar ◽

G. H. Bresnick

Keyword(s):

Lactic Acid ◽

Chromic Acid ◽

Periodic Acid ◽

Müller Cell ◽

External Limiting Membrane ◽

Electron Microscope Level ◽

Reactive Process ◽

Inner Limiting Membrane ◽

Muller Cell ◽

And Migration

After experimetnal damage to the retina with a variety of procedures Müller cell hypertrophy and migration occurs. According to Kuwabara and others the reactive process in these injuries is evidenced by a marked increase in amount of glycogen in the Müller cells. These cells were considered originally supporting elements with fiber processes extending throughout the retina from inner limiting membrane to external limiting membrane, but are known now to have high lactic acid dehydrogenase activity and the ability to synthesize glycogen. Since the periodic acid-chromic acid-silver methenamine technique was shown to demonstrate glycogen at the electron microscope level, it was selected to react with glycogen in the fine processes of the Müller cell that ramify among the neural elements in various layers of the retina and demarcate these cells cytologically. The Rhesus monkey was chosen as an example of a well vascularized retina and the rabbit as an example of a avascular retina to explore the possibilities of the technique.

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Single molecule optical diffraction: A tool for understanding the structure of triple stranded left-hand helical cellulose

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100157103 ◽

1989 ◽

Vol 47 ◽

pp. 1024-1025

Author(s):

George C. Ruben ◽

William Krakow

Keyword(s):

Single Molecule ◽

Helical Structure ◽

Optical Diffraction ◽

Maximum Diameter ◽

Primary Cell Wall ◽

Cellulose Synthesis ◽

Left Hand ◽

Left Handed ◽

Freeze Dried ◽

Diffraction Patterns

Tobacco primary cell wall and normal bacterial Acetobacter xylinum cellulose formation produced a 36.8±3Å triple-stranded left-hand helical microfibril in freeze-dried Pt-C replicas and in negatively stained preparations for TEM. As three submicrofibril strands exit the wall of Axylinum , they twist together to form a left-hand helical microfibril. This process is driven by the left-hand helical structure of the submicrofibril and by cellulose synthesis. That is, as the submicrofibril is elongating at the wall, it is also being left-hand twisted and twisted together with two other submicrofibrils. The submicrofibril appears to have the dimensions of a nine (l-4)-ß-D-glucan parallel chain crystalline unit whose long, 23Å, and short, 19Å, diagonals form major and minor left-handed axial surface ridges every 36Å.The computer generated optical diffraction of this model and its corresponding image have been compared. The submicrofibril model was used to construct a microfibril model. This model and corresponding microfibril images have also been optically diffracted and comparedIn this paper we compare two less complex microfibril models. The first model (Fig. 1a) is constructed with cylindrical submicrofibrils. The second model (Fig. 2a) is also constructed with three submicrofibrils but with a single 23 Å diagonal, projecting from a rounded cross section and left-hand helically twisted, with a 36Å repeat, similar to the original model (45°±10° crossover angle). The submicrofibrils cross the microfibril axis at roughly a 45°±10° angle, the same crossover angle observed in microflbril TEM images. These models were constructed so that the maximum diameter of the submicrofibrils was 23Å and the overall microfibril diameters were similar to Pt-C coated image diameters of ∼50Å and not the actual diameter of 36.5Å. The methods for computing optical diffraction patterns have been published before.

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