Viscoelastic properties of polyamic acid solutions?precursors of polyimides

1983 ◽  
Vol 23 (13) ◽  
pp. 713-718 ◽  
Author(s):  
S. A. Jenekhe
Keyword(s):  
Viscoelastic Properties ◽  
Acid Solutions ◽  
Polyamic Acid

The Viscoelastic Properties of Aqueous Poly(methacrylic acid) Solutions and Their Relations to Thermoreversible Gelation.

1992 ◽  
Vol 24 (12) ◽  
pp. 1419-1427 ◽  
Author(s):  
Kunio Nakamura ◽  
Takashi Itoh ◽  
Masao Sakurai ◽  
Tsurutaro Nakagawa
Keyword(s):  
Methacrylic Acid ◽  
Viscoelastic Properties ◽  
Acid Solutions ◽  
Thermoreversible Gelation

scholarly journals Features of Hyaluronic Acid Solutions for Intra-articular Introduction and Recent Trends in Their Development (Review)

2020 ◽  
Vol 9 (2) ◽  
pp. 45-54
Author(s):  
Y. Y. Zagorulko ◽  
E. Y. Zagorulko
Keyword(s):  
Molecular Weight ◽  
Hyaluronic Acid ◽  
Synovial Fluid ◽  
Viscoelastic Properties ◽  
Sodium Succinate ◽  
Acid Solutions ◽  
Molecular Weight Range ◽  
Polymer Complexes ◽  
Promising Area ◽  
The Creation

Introduction. The most common way to maintain the viscoelastic properties of synovial fluid is intra-articular administration of hyaluronic acid solutions. Such forms have several features due to the method of administration, the characteristics of the substance, as well as their composition, technology, and packaging. The aim of the work to analyze the features of hyaluronic acid solutions for intra-articular administration, as well as to consider resent trends to their pharmaceutical development.Text. Currently, in Russia, most of these forms are registered as medical devices. Each drug has its characteristics, including the source of the substance, the main molecular weight and the molecular weight range of hyaluronic acid, the structure of the molecule (linear or cross-linked), the method of its chemical modification, concentration, solution volume, dosage, etc. As excipients most often use sodium chloride, water for injection, and phosphate-buffered saline to maintain pH values close to the synovial fluid. Some prostheses contain mannitol as an antioxidant. Combinations of hyaluronic acid with active chondroprotective substances (chondroitin sulfate, sodium succinate) are known. The main type of primary packaging is glass prefilled syringes. The choice of sterilization methods is determined by the chemical structure of hyaluronic acid, aseptic production is used for most prostheses.Conclusion. Currently, research solutions to create thermostable and enzyme-resistant compositions with hyaluronic acid for intra-articular administration are being successfully applied. Modern developments are aimed at creating polymer complexes of hyaluronic acid with substances that improve the lubricity of solutions, the development of nanosystems (liposomes, nanoparticles, nano micelles, etc.) with chondroprotective, as well as the creation of inert biocompatible prostheses with viscoelastic properties. The creation of forms of hyaluronic acid and alternative drugs that can support the rheological properties of synovial fluid is currently a promising area of research.

Microrheology study of semidiluted deoxyribonucleic acid solutions

2010 ◽  
Vol 1277 ◽  
Author(s):  
F. Carvajal ◽  
J. G. Alvarez ◽  
E.R. Macías ◽  
V.V.A. Fernández ◽  
E. Robles-Avila ◽  
...  
Keyword(s):  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Sodium Salt ◽  
Viscoelastic Properties ◽  
Deoxyribonucleic Acid ◽  
Complex Viscosity ◽  
Elastic Behavior ◽  
Acid Solutions ◽  
Plateau Modulus ◽  
Calf Thymus

Linear rheological behavior and Microrheology measurements of sodium salt calf-thymus DNA aqueous solutions as a function of concentration are reported here. The microrheological behavior was obtained by a combination of experimental techniques: mechanical Rheometry and Dynamic light scattering (DLS). The viscoelastic properties of DNA in water as a function of concentration were performed at 20 °C and rheological and microrhelogical curves were performed. The result indicated that for concentrations lower than the entanglement concentration (Ce) the system exhibits a predominantly viscous behavior, whereas for higher concentrations exhibits a predominantly elastic behavior. The plateau modulus (G0) and the zero complex viscosity () follow a power law concentration dependence of the form: and , respectively The microrheology results overlap perfectly in a single line with the mechanical rheology results, extending the time resolution to faster breathing modes

Ultrastructural localization of specific nucleoprotein fractions

1978 ◽  
Vol 36 (2) ◽  
pp. 204-205
Author(s):  
G. L. Brown
Keyword(s):  
Gel Electrophoresis ◽  
Mouse Liver ◽  
Polyacrylamide Gel Electrophoresis ◽  
Ultrastructural Localization ◽  
Polyacrylamide Gel ◽  
Acid Extraction ◽  
Acid Solutions ◽  
Low Salt ◽  
Liver Nuclei ◽  
Phosphate Groups

Bismuth (Bi) stains nucleoproteins (NPs) by interacting with available amino and primary phosphate groups. These two staining mechanisms are distinguishable by glutaraldehyde crosslinking (Fig. 1,2).Isolated mouse liver nuclei, extracted with salt and acid solutions, fixed in either formaldehyde (form.) or gl utaraldehyde (glut.) and stained with Bi, were viewed to determine the effect of the extractions on Bi stainina. Solubilized NPs were analyzed by SDS-polyacrylamide gel electrophoresis.Extraction with 0.14 M salt does not change the Bi staining characteristics (Fig. 3). 0.34 M salt reduces nucleolar (Nu) staining but has no effect on interchromatinic (IC) staining (Fig. 4). Proteins responsible for Nu and glut.- insensitive IC staining are removed when nuclei are extracted with 0.6 M salt (Fig. 5, 6). Low salt and acid extraction prevents Bi-Nu staining but has no effect on IC staining (Fig. 7). When nuclei are extracted with 0.6 M salt followed by low salt and acid, all Bi-staining components are removed (Fig. 8).

Factors affecting the ability of dental cements to alter the pH of lactic acid solutions

2000 ◽  
Vol 27 (12) ◽  
pp. 1030-1033 ◽  
Author(s):  
M. Patel ◽  
H. Tawfik ◽  
Y. Myint ◽  
D. Brocklehurst ◽  
J. W. Nicholson
Keyword(s):  
Lactic Acid ◽  
Acid Solutions ◽  
Factors Affecting

Viscoelastic properties of a bent and straight dimeric liquid crystal

1993 ◽  
Vol 3 (5) ◽  
pp. 597-602 ◽  
Author(s):  
Gregory A. DiLisi ◽  
E. M. Terentjev ◽  
Anselm C. Griffin ◽  
Charles Rosenblatt
Keyword(s):  
Liquid Crystal ◽  
Viscoelastic Properties
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