UVB irradiation can induce apoptosis, morphologic changes, and altered expression of p53, Bcl-2, and hMSH2 in radial growth phase melanoma cell lines. Up-regulation of p53, Bcl-2, and hMSH2 suggests that these factors are involved in the altered balance between survival and apoptosis induced by UVB. Further investigation will be needed to determine if apoptosis and ultrastructural atypia reflect underlying DNA damage and genomic instability induced by UVB.
Reclaimed rubber powder (RRP) was treated by the addition of glycidyl methacrylate (GMA) to impart desired properties suitable for oil resistance applications. The produced GMA-RRP was mixed with nitrile-butadiene rubber (NBR) in various compositions. The blends were irradiated with gamma radiation doses of 50-250 kGy. The compounding of the blend factors has been elaborated using Fourier transform infrared spectroscopy and scanning electron microscopy (SEM). Different properties of the synthesized unirradiated and irradiated blends such as tensile strength, elongation at break, hardness, swelling behavior in motor and brake oils and thermal stability were investigated with respect to the RRP content. Results show that the tensile strength, hardness and swelling resistance increase with increasing NBR content in the blend. It has been shown that the tensile strength increased with dose. Similarly, hardness values, reported for the same composition, apparently increased with dose within the range of 50-250 kGy. The residual mass percentage of blends obviously increased upon the
Reclaimed rubber powder (RRP) was treated by the addition of maleic anhydride (MA) to impart desired properties suitable for self-adhesive sheets and concrete lining applications. The produced MA-RRP was mixed with natural rubber (NR) with various compositions. A fixed 1 : 1 blend ratio of NR : RRP was reinforced with various contents of glass fiber (GF) in an open two-roll mixing mill. The composites were irradiated using a 1.5 MeV electron beam accelerator at 30 and 50 kGy irradiation doses. Different properties of composite such as tensile strength, elongation at break, hardness, swelling behavior in different media, thermal stability, and scanning electron microscope (SEM) for both unirradiated and irradiated samples with respect to the RRP and GF content were investigated. Results show that the tensile strength and swelling resistance increase with increasing RRP content in the NR/RRP blends, whereas the elongation at break exhibit opposite trend. It can be observed that the hardness increases with increasing the fiber content.
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