Summary: The degree of plasma‐induced hydrophilization and the stability of the treatment are closely linked to the textile structure and the weave construction. This study investigates the plasma activation of polyester (PES) fabric structures to improve their wettability, as well as the aging effects. The hydrophilic modification is carried out by low pressure plasma treatments using oxygen containing gaseous mixtures (Ar/O2 and He/O2), and it is characterized by calculating contact angles (static and advancing) from capillary rise tests with water. In all cases, the wettability of plasma‐treated PES fabrics is improved significantly due to the formation of polar groups on the surface. In particular, the hydrophilicity of looser structured fabrics is improved remarkably as compared to tightly woven fabrics. Furthermore, the capillary phenomenon in fibrous assemblies is also described in this study.SEM image of a tightly woven fabric and the schematic representation of the liquid flow within a plasma‐hydrophilized fabric by capillary forces.magnified imageSEM image of a tightly woven fabric and the schematic representation of the liquid flow within a plasma‐hydrophilized fabric by capillary forces.

ABSTRACT:The surfaces of polyester (PET) fabrics and foils were modified by low-pressure RF plasmas with air, CO 2 , water vapor as well as Ar/O 2 and He/O 2 mixtures. To increase the wettability of the fabrics, the plasma processing parameters were optimized by means of a suction test with water. It was found that low pressure (10 -16 Pa) and medium power (10 -16 W) yielded a good penetration of plasma species in the textile structure for all oxygen-containing gases and gaseous mixtures used. While the wettability of the PET fabric was increased in all cases, the Ar/O 2 plasma revealed the best hydrophilization effect with respect to water suction and aging. The hydrophilization of PET fabrics was closely related to the surface oxidation and was characterized by XPS analysis. Static and advancing contact angles were determined from the capillary rise with water. Both wetting and aging demonstrated a good comparability between plasma-treated PET fabrics and foils, thus indicating a uniform treatment.

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Apoptosis similar to that seen in Alzheimer's disease patients was found in the brain of aged dogs by the TUNEL method of detecting in situ DNA fragmentation. Apoptosis was observed in both neurons and glial cells, and was morphologically characterized by round and swollen cytoplasm and aggregated nuclear chromatin, although these changes were slight. Neurons and astrocytes in the gray matter and oligodendrocytes in the white matter were affected. The number of ApopTag-positive brain cells increased slightly with age, but was not correlated to the number of senile plaques. A good correlation between the number of ApopTag-positive cells and the dementia index was clearly found. The present study indicates that brain cell apoptosis could account for dementia in aged dogs and suggested that aged dogs may be useful as a simplified animal model for Alzheimer's disease in man.

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