DSpace Community: 국내 학-연 극지연구 진흥프로그램 (PAP)
https://repository.kopri.re.kr/handle/201206/12722
국내 학-연 극지연구 진흥프로그램 (PAP)2024-01-13T09:41:23ZMicrobial Paleogenomics using marine sediment in the Antarctic Ocean
https://repository.kopri.re.kr/handle/201206/14581
Title: Microbial Paleogenomics using marine sediment in the Antarctic Ocean
Authors: Han, Duk Ki2023-07-26T00:00:00ZObservation of spatial and temporal patterns of seasonal ground deformation in central Yakutia using time series InSAR data in the freezing season
https://repository.kopri.re.kr/handle/201206/14584
Title: Observation of spatial and temporal patterns of seasonal ground deformation in central Yakutia using time series InSAR data in the freezing season
Authors: Jung, Yoon Taek; park, sangeun; Kim, Hyun-cheol
Abstract: The seasonal freeze/thaw variations of the active layer cause seasonal ground deformation, such as thaw subsidence in summer and frost heave in winter due to the cyclic phase changes of soil water. The Synthetic Aperture Radar (SAR) remote sensing, especially interferometric SAR (InSAR) techniques, has been proven to be a very useful tool for observing surface displacements of permafrost environments. Most previous studies on seasonal InSAR displacement have been concentrated in several study sites in the Arctic tundra regions. The objective of this study is to extend the InSAR analysis of seasonal ground deformations to boreal forest regions, where monitoring ground deformation is particularly important in terms of better understanding active layer dynamics under various ecological and geological conditions. In this study, we presented a strategy to analyze the time series SAR data in the freezing season to estimate the differential phase for seasonal ground deformation while overcoming the problem of coherence losses due to the rapid growth of vegetation during the short growing season. We applied the SBAS-based InSAR processing method to Sentinel-1 SAR in the central Yakutian lowlands, where boreal forests and thermokarst landforms are widely distributed, and retrieved frost-related displacement signals successfully. In addition to the magnitude of ground deformation in the freezing season, we further examined the temporal deformation pattern related to the progression of the freezing front in the soil during active freezing. Based on the Stefan solution, we proposed a piecewise linear model for the time series deformation. The proposed model divides the time series displacement according to the progression of freezing into three linear segments, and the slope parameter of each linear model can be interpreted as indicating the hydrological characteristics of the upper, middle, and lower parts of the soil. The results for the Yakutian lowlands illustrated the potential of SAR remote sensing to observe and quantify spatial details of the thermal and hydrological properties inside the active layer soil even in highly vegetated subarctic boreal forest areas.2023-01-01T00:00:00ZWistin Exerts an Anti-Inflammatory Effect via Nuclear Factor-κB and p38 Signaling Pathways in Lipopolysaccharide-Stimulated RAW264.7 Cells
https://repository.kopri.re.kr/handle/201206/13906
Title: Wistin Exerts an Anti-Inflammatory Effect via Nuclear Factor-κB and p38 Signaling Pathways in Lipopolysaccharide-Stimulated RAW264.7 Cells
Authors: An, Jangeun; Ryu, Gyoungah; Shin, Seong-Ah; Kim, Huiji; Ahn, Mi-Jeong; Lee, Jun Hyuck; Lee, Chang Sup
Abstract: Inflammation is an immune response to cellular damage caused by various stimuli (internal or external) and is essential to human health. However, excessive inflammatory re-sponses may be detrimental to the host. Considering that the existing drugs for the treatment of inflammatory diseases have various side effects, such as allergic reactions, stomach ulcers, and cardiovascular problems, there is a need for research on new anti-inflammatory agents with low toxicity and fewer side effects. As 4′,6-dimethoxyisoflavone-7-O-β-d-glucopyranoside (wistin) is a phytochemical that belongs to an isoflavonoid family, we investigated whether wistin could potentially serve as a novel anti-inflammatory agent. In this study, we found that wistin signifi-cantly reduced the production of nitric oxide and intracellular reactive oxygen species in lipo-polysaccharide-stimulated RAW 264.7 cells. Moreover, wistin reduced the mRNA levels of pro-inflammatory enzymes (inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX-2)) and cytokines (interleukin (IL)-1β and IL-6) and significantly reduced the protein expression of pro-inflammatory enzymes (iNOS and COX-2). Furthermore, wistin reduced the activation of the nuclear factor-кB and p38 signaling pathways. Together, these results suggest that wistin is a prospective candidate for the development of anti-inflammatory drugs.2022-09-01T00:00:00ZDevelopment of a broadband cavity-enhanced absorption spectrometer for simultaneous measurements of ambient NO3, NO2, and H2O
https://repository.kopri.re.kr/handle/201206/14091
Title: Development of a broadband cavity-enhanced absorption spectrometer for simultaneous measurements of ambient NO3, NO2, and H2O
Authors: Nam, Woohui; Cho, Changmin; Perdigones, Begie; Rhee, Tae Siek; Min, Kyung-Eun
Abstract: We describe the characteristics and performances of our newly built broadband cavity-enhanced absorption spectrometer for measurements of nitrate radical (NO3), nitrogen dioxide (NO2), and water vapor (H2O). A customized vibration-resistance cavity layout incorporated with N2 purging on high-reflection mirror surfaces was implemented with a red light-emitting diode (LED) as a light source. In general, this system achieved over 40 km (up to 101.5 km) of effective light path length at 662 nm from a 0.52 m long cavity. For the accurate NO3 measurement, the measured absorption spectrum of H2O was used for simultaneous concentration retrievals with the other species, instead of being treated as interferences to be removed or corrected prior to NO3 detection. Synthesized N2O5 crystals under atmospheric pressure were used for performance tests of linear response and transmission efficiency. From the standard injection experiments of NO3, NO2, and H2O, high linearities were observed (R2 ≥0.9918). The total NO3 transmission efficiency through the system was determined to be 81.2 % (±2.9, 1σ) within the residence time of 2.59 seconds. The precisions (1σ) of NO3, NO2, and H2O in 1 Hz measurement from a single pixel on the CCD were 1.41 pptv, 6.92 ppbv, and 35.0 ppmv with uncertainties of 10.8, 5.2, and ≥20.5 %, respectively, mainly from the errors in literature absorption cross-sections. The instrument was successfully deployed aboard the Korean icebreaker R/V Araon for an expedition conducted in remote marine boundary layer in the Arctic Ocean during the summer of 2021.2022-08-03T00:00:00Z