David Gan

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Salen-manganese complexes exhibit powerful superoxide dismutase and catalase activity, with pharmacologic efficacy in several oxidative-stress-associated disease models. Ultraviolet (UV) B not only induces direct DNA damage, but also generates oxidative stress. EUK-134, a salen-manganese complex, might therefore confer a direct protection against(More)
UVB irradiation can induce apoptotic, necrotic, and differentiation pathways in normal human keratinocytes. The present study was undertaken to determine at what dose of UVB each of these pathways is induced and whether these pathways are distinct or overlapping. We have observed that UVB induces fragmentation of DNA in human HaCaT keratinocytes, in a(More)
Human skin is exposed to an environment that varies in humidity from 100 to 0%, leading to seasonal variations in the condition of the skin. Exposure to a low humidity environment creates an osmotic gradient across the stratum corneum, which is known to modulate cutaneous barrier function. Heat shock proteins protect against stress-induced destabilization(More)
Cat's Claw (Uncaria tomentosa) water extracts, essentially free of oxindole alkaloids, have been shown to possess a broad spectrum of biological activity including DNA repair enhancement and antiinflammatory properties. These two biological mechanisms are key molecular targets to develop treatments that protect skin exposed to ultraviolet light from the(More)
Normal human dermal fibroblasts have a limited life-span in vitro and stop proliferation after a fixed number of cell divisions. This process by which cells stop proliferation is called senescence. Senescence is also characterized by a decrease in the total cell number. In this study, we characterized an increase in cell death in normal human dermal(More)
The objective of this paper is to present experimental results for testing the performance of different auction mechanisms related to the introduction of competitive markets for the generation of electricity. The research is based on the concept of smart markets introduced by Vernon Smith and a simulation model (PowerWeb) of a realistic bulk power system.(More)
Green tea chemoprevention has been a focus of recent research, as a polyphenolic fraction from green tea (GTP) has been suggested to prevent UV radiation-induced skin cancer. Recently, it was demonstrated that GTP reduced the risk for skin cancer in a murine photocarcinogenesis model. This was accompanied by a reduction in UV-induced DNA damage. These(More)
Appropriate routing protocol in data transfer is a challenging problem of network in terms of lower end-to-end delay in delivery of data packets with improving packet delivery ratio and lower overhead as well. In this paper we explain an effective and scalable AODV (called as AODV-ES) for Wireless Ad hoc Sensor Networks (WASN) by using third party reply(More)
The recent discovery of high concentrations of hydrogen just below the surface of Mars' polar regions by Mars Odyssey has enlivened the debate about past or present life on Mars. The prevailing assumption prior to the discovery was that the liquid water essential for its existence is absent. That assumption was based largely on the calculation of heat and(More)
Human skin, and its isolated cells, respond to insults with a variety of repair and protective mechanisms. One such mechanism is the production of heat shock proteins (HSPs). Heat shock proteins help the other cellular proteins fold correctly into their active three-dimensional structures. Therefore, they can enhance the survival of cells under harsh,(More)