731 research outputs found

    Monitoring Vegetation Change by Using Remote Sensing: An Examination of Visitor-Induced Impact at Cadillac Mountain, Acadia National Park

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    Cadillac Mountain, the highest peak along the eastern seaboard in the United States, is a major visitor destination at Acadia National Park. Managing vegetation impact on the summit of Cadillac Mountain is extremely challenging given the number of users and dispersed nature of visitor use at this fragile environmental setting. Since 2000, more intensive management strategies based on placing physical barriers to protect threatened vegetation and leave no trace signs have been employed to reduce vegetation impact and enhance vegetation recovery in the vicinity of the summit loop trail. A number of different change detection techniques and high resolution remote sensing datasets were utilized to identify vegetation impact and recovery from 1979 to 2007. The detection of spatial pattern of vegetation impact and recovery was at a much larger scale than typical recreation ecology studies. Study results showed detailed measurable vegetation regrowth and reduction at distances up to 90 meters from the summit loop trail, indicating overall positive effects in enhancing vegetation recovery in the vicinity of the summit loop trail compared to a nearby control site with similar environmental conditions but no visitor use. As expected, the vegetation recovery was higher as one moved away from the trail itself, and recovery was observed at a higher rate in the intermediate zone where visitor disturbance and ability for sites to regenerate would be higher than more natural variation of regrowth in the outer buffer zone with less visitor activity. It should be noted that overall minimal gains in vegetation regrowth was observed from 2001 to 2007, but compared with the time period of 1979 to 2001 there was more regrowth and less observed vegetation loss but total vegetation has not recovered to 1979 levels. The results also showed that, although with much less resolution than typical recreation ecology studies, vegetation diversity was lower at the experimental site at the level of plant family, suggesting limited success with enhancing vegetation diversity during the analysis time frame. Vegetation change detection using high resolution remote sensing datasets offers an approach for monitoring vegetation change dynamics and to some degree plant diversity, especially for a recreation setting in a sub-alpine environment with limited overstory vegetation such as the case at the summit of Cadillac Mountain. Remote sensing analysis could provide valuable baseline information for future visitorinduced impact monitoring programs and especially for dispersed recreation sites such as Cadillac Mountain

    Biological Effect of Gas Plasma Treatment on CO 2

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    Porous polycaprolactone (PCL) scaffolds were fabricated by using the CO2 gas foaming/salt leaching process and then PCL scaffolds surface was treated by oxygen or nitrogen gas plasma in order to enhance the cell adhesion, spreading, and proliferation. The PCL and NaCl were mixed in the ratios of 3 : 1. The supercritical CO2 gas foaming process was carried out by solubilizing CO2 within samples at 50°C and 8 MPa for 6 hr and depressurization rate was 0.4 MPa/s. The oxygen or nitrogen plasma treated porous PCL scaffolds were prepared at discharge power 100 W and 10 mTorr for 60 s. The mean pore size of porous PCL scaffolds showed 427.89 μm. The gas plasma treated porous PCL scaffolds surface showed hydrophilic property and the enhanced adhesion and proliferation of MC3T3-E1 cells comparing to untreated porous PCL scaffolds. The PCL scaffolds produced from the gas foaming/salt leaching and plasma surface treatment are suitable for potential applications in bone tissue engineering

    High resolution angle resolved photoemission studies on quasi-particle dynamics in graphite

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    We obtained the spectral function of the graphite H point using high resolution angle resolved photoelectron spectroscopy (ARPES). The extracted width of the spectral function (inverse of the photo-hole lifetime) near the H point is approximately proportional to the energy as expected from the linearly increasing density of states (DOS) near the Fermi energy. This is well accounted by our electron-phonon coupling theory considering the peculiar electronic DOS near the Fermi level. And we also investigated the temperature dependence of the peak widths both experimentally and theoretically. The upper bound for the electron-phonon coupling parameter is ~0.23, nearly the same value as previously reported at the K point. Our analysis of temperature dependent ARPES data at K shows that the energy of phonon mode of graphite has much higher energy scale than 125K which is dominant in electron-phonon coupling.Comment: 9 pages, 8 figures, accepted for publication in Phys. Rev.

    Effect of 660 nm Light-Emitting Diode on the Wound Healing in Fibroblast-Like Cell Lines

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    Light in the red to near-infrared (NIR) range (630–1000 nm), which is generated using low energy laser or light-emitting diode (LED) arrays, was reported to have a range of beneficial biological effects in many injury models. NIR via a LED is a well-accepted therapeutic tool for the treatment of infected, ischemic, and hypoxic wounds as well as other soft tissue injuries in humans and animals. This study examined the effects of exposure to 660 nm red LED light at intensities of 2.5, 5.5, and 8.5 mW/cm2 for 5, 10, and 20 min on wound healing and proliferation in fibroblast-like cells, such as L929 mouse fibroblasts and human gingival fibroblasts (HGF-1). A photo illumination-cell culture system was designed to evaluate the cell proliferation and wound healing of fibroblast-like cells exposed to 600 nm LED light. The cell proliferation was evaluated by MTT assay, and a scratched wound assay was performed to assess the rate of migrating cells and the healing effect. Exposure to the 660 nm red LED resulted in an increase in cell proliferation and migration compared to the control, indicating its potential use as a phototherapeutic agent

    Prognostic Value of Postoperative CEA Clearance in Rectal Cancer Patients with High Preoperative CEA Levels

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    PURPOSE: We determined the prognostic value of carcinoembryonic antigen (CEA) clearance after tumor resection with serial evaluation of postoperative CEA levels in rectal cancer. METHODS: Between 1994 and 2004, we retrospectively reviewed 122 patients with rectal cancer whose serum CEA levels were measured on the preoperative day and postoperative days 7 and 30. Patients with preoperative CEA levels <5.0 ng/ml were excluded. An exponential trend line was drawn using the three CEA values. Patients were categorized into three groups based on R(2) values calculated through trend line, which indicates the correlation coefficient between exponential graph and measured CEA values: exponential decrease group (group 1: 0.9 < R(2) < or = 1.0), nearly exponential decrease group (group 2: 0.5 < R(2) < or = 0.9), and randomized clearance group (group 3: 0.5 < or = R(2)). We then analyzed the CEA clearance pattern as a prognostic indicator. RESULTS: With a median follow-up of 57 months, the 5-year overall survival was 62.3% vs. 48.1% vs. 25% and the 5-year disease-free survival was 58.6% vs. 52.7% vs. 25% among groups 1, 2, and 3 (P = 0.014, P = 0.027, respectively) in patients with stage III rectal cancer. For those with stage II rectal cancer, the 5-year overall survival rate of group 1 was significantly better than groups 2 and 3 (88.8% vs. 74.1%, respectively, P = 0.021). CONCLUSIONS: the postoperative pattern of CEA clearance is a useful prognostic determinant in patients with rectal cancer. Patients with a randomized pattern of CEA clearance after tumor resection should be regarded as having the possibility of a persistent CEA source and may require consideration of intensive follow-up or adjuvant therapy.ope
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