Step-Stress Accelerated Degradation Analysis for Highly Reliable Products

While the degradation of Polylactic Acid (PLA) has been studied for several years, results regarding the mechanism for determining degradation are not completely understood. Through accelerated degradation testing, data can be extrapolated and modeled to test parameters such as temperature, voltage, time, and humidity. Accelerated lifetime testing is used as an alternative to experimentation under normal conditions. The methodology to create this model consisted of fabricating series of ASTM specimens using extrusion and injection molding. These specimens were tested through accelerated degradation; tensile and flexural testing were conducted at different points of time. Nonparametric inference tests for multivariate data are presented. The results indicate that the effect of the independent variable or treatment effect (time) is highly significant. This research intends to provide a better understanding of biopolymer degradation. The findings indicated that the proposed statistical models can be used as a tool for characterization of the material regarding the durability of the biopolymer as an engineering material. Having multiple models, one for each individual accelerating variable, allow deciding which parameter is critical in the characterization of the material.

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Accelerated degradation of retinoic acid by activated microglia

Pharmacopsychiatry ◽

10.1055/s-0033-1353273 ◽

2013 ◽

Vol 46 (06) ◽

Author(s):

J Hellmann-Regen ◽

G Kronenberg ◽

R Uhlemann ◽

D Freyer ◽

M Endres ◽

...

Keyword(s):

Retinoic Acid ◽

Activated Microglia ◽

Accelerated Degradation

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A Collaborative Study to Establish the Second International Standard for Streptokinase

Thrombosis and Haemostasis ◽

10.1055/s-0038-1647298 ◽

1990 ◽

Vol 64 (02) ◽

pp. 267-269 ◽

Cited By ~ 7

Author(s):

A B Heath ◽

P J Gaffney

Keyword(s):

High Purity ◽

Collaborative Study ◽

World Health Organisation ◽

World Health ◽

Clot Lysis ◽

Current Standard ◽

International Standard ◽

Accelerated Degradation ◽

The World ◽

International Collaborative Study

SummaryAn International Standard for Streptokinase - Streptodomase (62/7) has been used to calibrate high purity clinical batches of SK since 1965. An international collaborative study, involving six laboratories, was undertaken to replace this standard with a high purity standard for SK. Two candidate preparations (88/826 and 88/824) were compared by a clot lysis assay with the current standard (62/7). Potencies of 671 i.u. and 461 i.u. were established for preparations A (88/826) and B (88/824), respectively.Either preparation appeared suitable to serve as a standard for SK. However, each ampoule of preparation A (88/826) contains a more appropriate amount of SK activity for potency testing, and is therefore preferred. Accelerated degradation tests indicate that preparation A (88/826) is very stable.The high purity streptokinase preparation, coded 88/826, has been established by the World Health Organisation as the 2nd International Standard for Streptokinase, with an assigned potency of 700 i.u. per ampoule.

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