Effect of Pendant Group Structure on the Hydrolytic Stability of Polyaspartamide Polymers under Physiological Conditions

2012 ◽  
Vol 13 (5) ◽  
pp. 1296-1306 ◽  
Author(s):  
Yijie Lu ◽  
Mokit Chau ◽  
A. J. Boyle ◽  
Peng Liu ◽  
Ansgar Niehoff ◽  
...  
Keyword(s):  
Group Structure ◽  
Hydrolytic Stability ◽  
Pendant Group ◽  
Physiological Conditions

Waterborne polyurethane conjugated with novel diol chain-extender bearing cyclic phosphoramidate lateral group: synthesis, flammability and thermal degradation mechanism

RSC Advances ◽  
2016 ◽  
Vol 6 (61) ◽  
pp. 56610-56622 ◽  
Author(s):  
Peikun Zhang ◽  
Zhenyu Zhang ◽  
Haojun Fan ◽  
Saiqi Tian ◽  
Yi Chen ◽  
...  
Keyword(s):  
Thermal Degradation ◽  
Flame Retardancy ◽  
Degradation Mechanism ◽  
Hydrolytic Stability ◽  
Waterborne Polyurethane ◽  
Chain Extender ◽  
Pendant Group ◽  
Thermal Degradation Mechanism ◽  
Lateral Group

A diol bearing cyclic phosphoramidate pendant group was synthesized and covalently conjugated into waterborne polyurethane. The polyurethane possesses long-term hydrolytic stability and good intrinsic flame retardancy.

The effect of pendant group structure on the thermoresponsive properties of N-substituted polyesters

2017 ◽  
Vol 8 (46) ◽  
pp. 7195-7206 ◽  
Author(s):  
John P. Swanson ◽  
Megan A. Cruz ◽  
Leanna R. Monteleone ◽  
Michael R. Martinez ◽  
Philip J. Costanzo ◽  
...  
Keyword(s):  
Group Structure ◽  
Pendant Group ◽  
Structure Property ◽  
Correlation Studies ◽  
Property Correlation ◽  
Cloud Points

Structure–property correlation studies of a diverse set of biodegradable thermoresponsive polyesters provides a rationale for the design of thermoresponsive polyesters with desired cloud points.

scholarly journals PRELIMINARY DETERMINATION OF HYDROLYTIC STABILITY OF A PYRROLE-BASED HYDRAZIDE AND ITS HYDRAZONE

2018 ◽  
Vol 6 ◽  
pp. 1192-1198 ◽  
Author(s):  
Diana Tzankova ◽  
Lily Peikova ◽  
Maya Georgieva
Keyword(s):  
Chemical Stability ◽  
Hydrolytic Stability ◽  
Acidic Ph ◽  
Physiological Conditions ◽  
Ph Values ◽  
Blood Ph ◽  
Stomach Ph ◽  
Physiological Values ◽  
Preliminary Determination

A validated UV/VIS method for preliminary determination of the chemical stability and stability in close to physiological conditions of a model pyrrole hydrazide and its corresponding derivative, bearing susceptible to hydrolysis hydrazone group was developed. The evaluated substances were subjected to the influence of a variety of pH medias, representing the main physiological values of 37°C and corresponding pH values in the stomach (pH 2.0), blood (pH 7.4) and small intestine (pH 9.0). The chemical stability at strong alkali media of pH 13.0 was also evaluated. The hydrazide was found to be stable at all investigated conditions. The tested hydrazone was determined to be stable at pH of 7.4 and a temperature of 37°C and susceptible to hydrolysis at strong acidic (pH 2.0) and moderate alkali (pH 9.0) media at the same temperature. In addition, a decrease in the absorption at strong alkali media (pH 13.0) was observed, showing the compounds instability under these conditions.

Macromolecular stereochemistry: the effect of pendant group structure on the axial dimension of polyisocyanates

1987 ◽  
Vol 20 (5) ◽  
pp. 992-999 ◽  
Author(s):  
Mark M. Green ◽  
Richard A. Gross ◽  
Charles Crosby ◽  
Frederic C. Schilling
Keyword(s):  
Group Structure ◽  
Pendant Group ◽  
Axial Dimension

Macromolecular stereochemistry: effect of pendant group structure on the conformational properties of polyisocyanides

1988 ◽  
Vol 21 (6) ◽  
pp. 1839-1846 ◽  
Author(s):  
Mark M. Green ◽  
Richard A. Gross ◽  
Frederic C. Schilling ◽  
Karl Zero ◽  
Charles Crosby
Keyword(s):  
Group Structure ◽  
Pendant Group ◽  
Conformational Properties

Ultrastructure of Giant Mitochondria and Their Inclusions in Schwann Cells of Bovine Splenic Nerve

1974 ◽  
Vol 32 ◽  
pp. 194-195
Author(s):  
Å. Thureson-Klein
Keyword(s):  
Schwann Cells ◽  
Cell Organelles ◽  
Giant Mitochondria ◽  
Matrix Density ◽  
Physiological Conditions ◽  
Unmyelinated Axons ◽  
Internal Structures ◽  
Structural Abnormalities ◽  
Cytotoxic Compounds ◽  
Cell Components

Giant mitochondria of various shapes and with different internal structures and matrix density have been observed in a great number of tissues including nerves. In most instances, the presence of giant mitochondria has been associated with a known disease or with abnormal physiological conditions such as anoxia or exposure to cytotoxic compounds. In these cases degenerative changes occurred in other cell organelles and, therefore the giant mitochondria also were believed to be induced structural abnormalities.Schwann cells ensheating unmyelinated axons of bovine splenic nerve regularly contain giant mitochondria in addition to the conventional smaller type (Fig. 1). These nerves come from healthy inspected animals presumed not to have been exposed to noxious agents. As there are no drastic changes in the small mitochondria and because other cell components also appear reasonably well preserved, it is believed that the giant mitochondria are normally present jin vivo and have not formed as a post-mortem artifact.

Freeze-fracture observations on changes in the distribution of Filipin-sterol complexes during epididymal maturation and capacitation of boar spermatozoa

1990 ◽  
Vol 48 (3) ◽  
pp. 90-91
Author(s):  
N. Seki ◽  
Y. Toyama ◽  
T. Nagano
Keyword(s):  
Plasma Membrane ◽  
Essential Role ◽  
Freeze Fracture ◽  
Final Concentration ◽  
Freeze Fracturing ◽  
Physiological Conditions ◽  
Epididymal Maturation ◽  
Cacodylate Buffer ◽  
Sperm Membrane ◽  
Boar Spermatozoa

It is believed that i ntramembra.nous sterols play an essential role in membrane stability and permeability. To investigate the distribution changes of sterols in sperm membrane during epididymal maturation and capacitation, filipin has been used as a cytochemical probe for the detection for membrane sterols. Using this technique in combination with freeze fracturing, we examined the boar spermatozoa under various physiological conditions.The spermatozoa were collected from: 1) caput, corpus and cauda epididymides, 2) sperm rich fraction of ejaculates, and 3)the uterus 2hr after natural coition. They were fixed with 2.5% glutaraldehyde in 0.05M cacodylate buffer (pH 7.4), and treated with the filipin solution (final concentration : 0.02.0.05%) for 24hr at 4°C with constant agitation. After the filipin treatment, replicas were made by conventional freeze-fracture technique. The density of filipin-sterol complexes (FSCs) was determined in the E face of the plasma membrane of head regions.

Some effects of unequal distribution of information in a wheel group structure.

1954 ◽  
Vol 49 (4, Pt.1) ◽  
pp. 554-556 ◽  
Author(s):  
J. C. Gilchrist ◽  
Marvin E. Shaw ◽  
L. C. Walker
Keyword(s):  
Group Structure ◽  
Unequal Distribution
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