Efficacy of cap-assisted colonoscopy according to lesion location and endoscopist training level

AIM: To evaluate the efficacy of cap-assisted colonoscopy(CAC) for detection of colorectal polyps and adenomas according to the lesion location and endoscopist training level.METHODS: Patients 20 years or older, who underwent their first screening colonoscopy in a single tertiary center from May 2011 to December 2012 were enrolled in this study. All patients underwent either CAC or standard colonoscopy(SC), and all of the procedures were performed by 11 endoscopists(8 trainees and 3 experts). All procedures were performed with highdefinition colonoscopes and narrow band imaging. The eight trainees had experiences of performing 150 to 500 colonoscopies, and the three experts had experiences of performing more than 3000 colonoscopies. A 4-mmlong transparent cap was attached to the end of a colonoscope in the CAC group. We retrospectively evaluated the number of polyps and adenomas, polyp detection rate(PDR), and the number of adenomas and adenoma detection rate(ADR) according to the lesion location and endoscopist training level between CAC and SC. We also evaluated the number of polyps and adenomas according to their size between CAC and SC.RESULTS: Overall, PDR and ADR using CAC were significantly higher than those using SC for both whole colon(48.5% vs 40.7%, P = 0.012; 35.7% vs 28.3%, P = 0.012) and right-side colon(35.3% vs 26.6%, P = 0.002; 27.0% vs 16.9%, P < 0.001). The number of polyps and adenomas per patient using CAC was significantly higher than that using SC for both the whole colon(1.07 ± 1.59 vs 0.82 ± 1.31, P = 0.008; 0.72 ± 1.32 vs 0.50 ± 1.01, P = 0.003) and right-side colon(0.66 ± 1.18 vs 0.41 ± 0.83, P < 0.001; 0.46 ± 0.97 vs 0.25 ± 0.67, P < 0.001). In the trainee group, the PDR and ADR using CAC were significantly higher than those using SC for both the whole colon(46.7% vs 39.7%, P = 0.040; 33.9% vs 26.0%, P =0.012) and right-side colon(34.2% vs 26.5%, P = 0.015; 25.3% vs 15.9%, P = 0.001). In the expert group, the PDR and ADR using CAC were significantly higher than those using SC only for the right-side colon(42.1% vs 27.0%, P =0.035; 36.8% vs 21.0%, P = 0.020).CONCLUSION: CAC is more effective than SC for detection of colorectal polyps and adenomas, especially when performed by trainees and when the lesions are located in the right-side colon.

Effects of an Urban Park and Residential Area on the Atmospheric CO_2 Concentration and Flux in Seoul,Korea

The CO2 concentrations and fluxes over an urban forest site （Namsan） and an urban residential region （Boramae） in Seoul, Korea, during the non-growing season （2 4 March 2011）, the growing season （10-12 June 2011）, and the late-growing season （22-24 September 2011） were analyzed. The CO2 concentrations of two sites showed nearly the same diurnal variation, with a maximum value occurring during the night and a minimum value occurring during daytime, as well as the same seasonal variation, with a maximum value during the non-growing season （early spring） and a minimum value during the growing season （summer）. The CO2 flux over the urban forest did not show any typical diurnal variation during the non-growing season, but did show diurnal variation with a small positive value during the night and a large negative value during daytime in the growing and late-growing seasons due to photosynthesis in the urban forest. The CO2 flux over the urban residential region showed a positive daily mean value for all periods, with large values during the non-growing season and small values during the growing season, and it also showed diurnal variation with two maxima at 0600-1000 LST and 1800-2400 LST, and two minima at 0300-0600 LST and 1100-1500 LST, and was strongly correlated with the use of liquefied natural gas for cooking and heating by surrounding houses.

Deduction of a meteorological phenology indicator from reconstructed MODIS LST imagery

Phenology is a valuable attribute of vegetation to assess the biological impacts from climate change.A challenge of phenological research is to obtain information on both high temporal resolution and fine spatial scale observations.Here,we constructed an air temperature map based on temporal merging and spatial interpolation algorithms to overcome the cloud-related problem from the MODIS LST product.Then,we derived the accumulated growing degree days(AGDD)from the constructed mean air temperature map to use as a meteorological indicator.Further,we verified the indicator with the seasonal mean air temperature and the green-up date of a Quercus mongolica forest determined from the field-based measurements.The AGDD threshold for each Q.mongolica forest when the first leaf has unfolded was detected from the EXG trajectory extracted from digital camera images.A comparison between meteorological and MODIS-derived AGDD showed good agreement between them.There was also high consistency between DoYs extracted from AGDD and EVI based on curvature K for Q.mongolica forests of 30 sampling sites throughout South Korea.The results prove that microclimatic factors such as elevation,waterbody,and land-use intensity were faithfully reflected in the reconstructed images.Therefore,the results of this study could be applied effectively in areas where microclimatic variation is very severe and for monitoring phenology of undergrowth,which is difficult to detect from reflectance imaging.

Early recovery process and restoration planning of burned pine forests in central eastern Korea

In central eastern Korea, there has been a continued effort to sustain pine forests because of their value for wood and mushroom production, as well as for other resources. Through the analysis of previously burned areas,we clarified the effects of fire on vegetation dynamics of pine forests by measuring changes in species composition,population structure, and the growth rates of major tree species. Vegetation analysis was conducted on a series of 100 m^2 plots established in Korean red pine(Pinus densiflora Siebold. & Zucc.) and Mongolian oak(Quercus mongolica Fisch. Ex Ledeb.) forests situated in three different topographic positions on slopes where fire severity varied. We confirmed that most pine trees will succumb to even a surface fire, whereas oak may be killed following high intensity or infrequent fires but will sprout and become dominant. Complete protection from fire favors other, more shade-tolerant deciduous hardwoods. Different restoration plans apply, based on observed vegetation responses for each topographic zone. Near the ridge top,where pine seed sources are most limited, it may be necessary to restore pine forests by planting and to control competing shrubs and herbs. At the mountain foot, where exotic species and species modified by hybridization have invaded aggressively, restoration that involves the introduction of natural vegetation is required. Mid-slope sites,where pine has been replaced by natural vegetation dominated by Mongolian oak, do not require any form of restorative treatment.