Browsing UAF Graduate School by Title
Now showing items 3493-3496 of 3496
Zinc oxide nanoparticles and SH-SY5Y cell lineThe Arctic and sub-arctic regions are impacted by the growth of the global nanotechnology industry. Nanomaterials have unique chemical and physical properties that may lead to toxicological effects that interfere with normal cellular metabolism. Zinc oxide nanoparticles (ZnO NPs) are now very common and widely used in daily life. In industry, ZnO NPs are used to protect different materials from damage caused by UV exposure. The scientific literature suggests that ZnO NPs can have negative impacts on both living organisms and plants. However, there is a paucity of research on the mechanisms by which ZnO NPs may affect the neuronal cells. This study investigates how ZnO NPs interact with the neuroblastoma cell line SH-SY5Y. Using transmission electron microscopy, we observed that the ZnO NPs form 36 nm particles on average, and increase the level of vascular endothelial growth factor (VEGF) in extracellular fluid, as measured by an enzyme-linked immunosorbent assay (ELISA). Moreover, ZnO NPs, in presence of tumor neucrosis factor- α (TNF-α), can also decrease the level of extracellular VEGF compared with TNF-a treatment alone. These findings suggest the basis for more studies on understanding the mechanism by which ZnO NPs impact cytokine signaling. Another direction is using ELISA technology to observe the interactions of NPs with different cell types such as neuronal stem cells.
Zooarchaeological analysis at 49-RAT-32: historical ecology and maritime subsistence in the late Aleutian periodThis thesis utilizes a zooarchaeological collection from 49-RAT-32 on Amchitka Island in the Western Aleutians to examine Unangax̂ subsistence strategies, and human/environment interactions from 620 ± 20 to 320 ± 20 years B.P. The materials used for this analysis were recovered from primary and secondary fill overlaying the House 1 floor. Paleoecological records within this region are limited and conflict with each other, but the cool and wet conditions of the Little Ice Age 600-100 years B.P, or C.E. 1350-1850 are believed to be in effect during the deposition of the fill materials. Marine mammal, fish, and sea urchin remains were analyzed to understand subsistence practices, seasonality, and land/seascape use. The relative abundance of the exploited taxa and fork lengths of marine fishes were analyzed to identify potential resource stress and change over time. Atka mackerel dominates the faunal assemblage and Pacific cod are present in very low frequencies, both of which make 49-RAT-32 unique when compared to other Aleutian assemblages. Atka mackerel, Pacific cod, and Irish lords are larger in size than their modern counterparts, with the large size of Pacific cod indicating deep sea fishing practices. The size differentials in Atka mackerel and Irish lords may reflect differences in ocean conditions. This analysis of fauna from 49-RAT-32 does not indicate the presence of human-driven resource depression, in fact, fish sizes were increasing, and diet breadth was shrinking. The opposite pattern from what would be expected if humans were overfishing. The data from this analysis increase our understanding of resource utilization and landscape use during the Late Aleutian Period, and provides baseline information for future studies analyzing changes in fish size over time.
Zooplankton abundance, community structure, and oceanography northeast of Kodiak Island, AlaskaZooplankton community dynamics and correlations with physical characteristics of the water were studied in the northwestern Gulf of Alaska. Zooplankton were collected systematically northeast of Kodiak Island, Alaska in March, May, August and November of 2002 to 2004. Species composition, total abundance and spatial community structure were correlated to physical variables. Small copepods (numerically>50%) dominated the zooplankton composition and were most abundant in August. Average biomass was 48.7 g WW m⁻² in May and 52.0 g WW m⁻² in August in Kodiak region. Interannual zooplankton abundance variations were large, with May 2003 having a dramatically higher abundance (2x10⁴ individual m⁻³ higher) than 2002 and 2004, probably due to the higher temperature (1° C higher) and lower salinity in May 2003. Small to moderate correlations (r<0.7) were found between temporal zooplankton abundance and selected physical variables. Spatial patterns in zooplankton composition among stations were more discernable in May than in August, likely due to water column stability in the spring and more dynamic influences in the summer, but revealed no consistent spatial patterns. The zooplankton community patterns in this region thus appear to arise due to complex oceanographic and bathymetric interactions, and suggest high variability can occur in the availability of prey for higher trophic levels.
Zooplankton ecology of Norton Sound, AlaskaThe zooplankton distribution in Norton Sound was monitored for the Outer Continental Shelf Environmental Assessment Program. Salinity, temperature, and predation were investigated as factors controlling species composition and community structure. Sampling was concentrated along the eastern coast of Norton Sound during July and August, 1976. The copepod Acartia clausi and the cladocerans Evadne sp. and Podon sp. were numerically dominant in the samples. These species are able to tolerate the widely ranging salinities and temperatures of the coastal waters. The A. clausi population abundance was correlated with water temperature, while cladoceran and larval mollusc populations were correlated with salinity. No differences in species composition were discerned between stations along the shallow coast; however, the seaward community contained a greater diversity of organisms supporting a larger planktonic carnivore biomass. Zooplankton was a numerically dominant item in the diets of many fish species, although the epibenthic mysid community was volumetrically most important.