• Journal of the Korean Geographical Society
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• v.40 no.4 s.109
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• pp.428-440
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• 2005

There is currently no agreement among archaeologists, environmental historians, and paleoecologists as to the relative significance of pre- and post-Conquest human impact on the environments of Highland Mexico. This paper presents the results of pollen, microscopic charcoal, dung fungal spore, isotope, and magnetic susceptibility analyses on ca. 4m sediment core. The coring site is Hoya Rincon de Parangueo, one of the seven maar lakes in the Valle do Santiago. Amaranthaceae pollen, one of important disturbance indicators and Zea mays pollen obviously indicate two periods of agricultural activities. The first period begins ca. 400 B.C. and ends ca. A.D. 850. The second begins around A.D. 1550 and continues to the present. During the first period, the degree of agricultural activities was related to periodical sunspot cycles and the most intense activities were present between ca. A.D. 150-ca. A.D. 400. The abrupt increase of $\delta^{18}O$ around 280cm may reflect that an important transition to a dry phase took place around A.D. 450. People probably stopped cultivating crops due to dry conditions prevailing since ca. A.D. 450. The second period, the post-Conquest, exhibits a dramatic increase of sporormiella, dung fungal spores resulted fron the introduction of cattle. Low Poaceae frequency and charcoal production and high $\delta^{13}C$ values, magnetic susceptibility, and organic contents all indicate the arrival of the Spanish. Most importantly, it seems that mesquite (Prosopis juliflora) could have benefits from declined fire frequencies caused by cattle grazing. The study area is now entirely dominated by woody plants like mesquite, which clearly demonstrates that serious vegetation change occurred in the study area.

• Journal of the Mineralogical Society of Korea
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• v.22 no.2
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• pp.139-151
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• 2009

Mineralogical characteristics of secondary precipitate formed at some mineral water springs in Gyeongbuk Province, Korea were studied in relation to water chemistry. The chemical water types of mineral water springs are mostly classified as $Ca-HCO_3$ type, but $Na(Ca)-HCO_3$ and $Ca-SO_4$ types are also recognized. Ca, Fe, and $HCO_3\;^-$ are the most abundant components in the water. The pH values of most springs lie in 5.76${\sim}$6.81, except Hwangsu spring having pH 2.8. Saturation indices show that all springs are supersaturated with respect to iron minerals and oxyhydroxides such as hematite and goethite. The result of particle size analysis shows that the precipitate is composed of the composite with various sizes, indicating the presence of iron minerals susceptible to a phase transition at varying water chemistry or the mixtures consisting of various mineral species. The particle size of the reddish precipitate is larger than that of the yellow brown precipitate. Based on XRD and SEM analyses, the precipitate is mostly composed of ferrihydrite (two-line type), goethite, schwertmannite, and calcite, with lesser silicates and manganese minerals. The most abundant mineral fanned at springs is ferrihydrite whose crystals are $0.1{\sim}2\;{\mu}m$ with an average of $0.5\;{\mu}m$ in size, characterized by a spherical form. It should be interestingly noted that schwertmannite forms at Hwangsu spring whose pH is very low. At Shinchon spring, Gallionella ferruginea, one of the iron bacteria, is commonly found as an indicator of the important microbial activity ascribed to the formation of iron minerals because very fine iron oxides with a spherical form are closely distributed on surfaces of the bacteria. A genetic relationship between the water chemistry and the formation of the secondary precipitate from mineral water springs was discussed.

• Clean Technology
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• v.24 no.2
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• pp.112-118
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• 2018

Thermo-responsive polymers that exhibit phase transition in response to temperature change can be used as materials for smart windows because they can control solar light transmission depending on the outside temperature. The development of thermo-responsive polymers for smart windows that can be used over a wide temperature range is desirable. To obtain high performance smart windows materials, three-dimensional thermo-responsive poly(N-isopropylacrylamide) (PNIPAm) gels were prepared by free radical polymerization from monomer N-isopropylacrylamide, N, N'-methylenebis acrylamide (MBAm) as a crosslinking agent, ammonium persulfate (APS) as a strong oxidizing agent/tetramethylene diamine as a catalyst, and a mixture of two solvents (water/glycerol). This study examined the effect of glycerol content on the lower critical solution temperature (LCST), freezing temperature and the solar light transmittance of crosslinked PNIPAm gel films. The LCST and freezing temperature of PNIPAm gel films were found to be significantly decreased from 34.3 and $6.3^{\circ}C$ to 28.2 and $-6.5^{\circ}C$ with increasing glycerol content from 0 wt% to 10 wt%, respectively. It was found that the transparent PNIPAm gel films at $25^{\circ}C$ (temperature < LCST) were converted to translucent gels at higher temperature ($45^{\circ}C$) (temperature > LCST). These results suggested that the crosslinked PNIPAm gel materials prepared in this study could have high potential for application in smart glass materials.

• Tuberculosis and Respiratory Diseases
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• v.45 no.4
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• pp.776-784
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• 1998

Background: The cyclin D1 gene is one of the most frequently amplified chromosomal regions(11q13) in human carcinomas. In laryngeal and head and neck carcinomas, its overexpression has been shown to be associated with advanced local invasion and presence of lymph node metastases. Cyclin D1 may therefore playa key role in cell growth regulation and tumorigenesis. Lung cancer is a worldwide problem and in many contries it is the most lethal malignancy. As relapse is frequent after resection of early stage non-small cell lung cancer, there is an urgent need to define prognostic factors. Purpose: This study was undertaken to evaluate the prognostic value of the cyclin D1, that is one the G1 cyclins which control cell cycle progression by allowing G1 to S phase transition, on the patients in radically resected non-small cell lung cancer. Method: Total 81 cases of formalin-fixed paraffin-embedded blocks from resected primary non-small cell lung cancer from January 1, 1983 to July 31, 1995 at Hanyang University Hospital were available for both clinical follow-up and immunohistochemical staining using monoclonal antibodies for cyclin D1. Results : The histologic classification of the tumor was based on WHO criteria, and the specimens included 45 squamous cell carcinomas, 25 adenocarcinomas and 11 large cell carcinomas. Cyclin D1 overexpression was noted in 26 cases of 81 cases tested (30.9%). Cyclin D1 expression was not significantly associated with cell types of the tumor, pathological staging and the size of the tumor. But cyclin D1 overexpression was significantly correlated with positive lymph node metastasis(p=0.035). The mean survival duration was $22.76{\pm}3.50$ months in cyclin D1 positive group and $45.38{\pm}5.64$ months in eyclin D1 negative group. There was a nearly significant difference in overall survival between cyclin D1 positive and negative groups(p=0.0515) in radically resected non-small cell lung cancer. Conclusion: Based on this study, cyelin D1 overexpression appears an important poor prognostic indicator in non-small cell lung cancer and may have diagnostic and prognostic importance in the treatment of resectable non-small cell lung cancer.

• Korean Chemical Engineering Research
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• v.46 no.5
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• pp.988-993
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• 2008

The characteristics of NO oxidation using sodium chlorite ($NaClO_2$) powder have been investigated by a flow type packed-bed reactor, where the reaction temperature and the space velocity are varied in the range of $20{\sim}230^{\circ}C$ and $0.4-2.2{\times}10^5hr^{-1}$, respectively, and the simulation gas mixtures are composed of NO (0~200 ppm), $NO_2$ (0-200 ppm), $O_2$ (0~15%) and $H_2O$ (0~15%) within $N_2$ balance. It has been found that the oxidation efficiency of NO depends greatly on the reaction temperature, exhibiting the existence of critical reaction temperature at about $170^{\circ}C$ where the oxidation efficiency of NO is maximized and then abruptly decreased with further increase of reaction temperature, resulting in being negligible over $190^{\circ}C$. Such a behavior in the oxidation efficiency has been originated from the phase transition of $NaClO_2$ at about $170^{\circ}C$ to form $NaClO_3$, and NaCl which are chemically inactive toward the oxidation of NO. The chemical reaction of NO with $NaClO_2$ has been observed to produce $NO_2$, ClNO and $ClNO_2$, whereas that of $NO_2$ only OClO species. Additionally, we have also observed that the introduction of $O_2$ and $H_2O$ has little influence on the oxidation of NO.

• Radiation Oncology Journal
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• v.16 no.4
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• pp.377-388
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• 1998

Purpose : To evaluate changes in expression of cell cycle related genes during apoptosis induced in HL60 cells by X-irradiation to understand molecular biologic aspects in mechanism of radiation therapy. Material and Methods : HL-60 cell line (promyelocytic leukemia cell line) was grown in culture media and irradiated with 8 Gr by linear accelerator (6 MV X-ray). At various times after irradiation, ranging from 3 to 48 hours were analyzed apoptotic DNA fragmentation assay for apoptosis and by western blot analysis and semi-quantitative RT-PCR for expression of cell cycle related genes (cyclin A, cyclin B, cyclin C, cyclin Dl, cyclin E, cdc2, CDK2, CDK4, $p16^{INK4a}$, $p21^{WAF1}$, $p27^{KIP1}$, E2F, PCNA and Rb). Results : X-irradiation (8 Gy) induced apoptosis in HL-60 cell line. Cycline A protein increased after reaching its peak 48 h after radiation delivery and cyclin E, E2F, CDK2 and RB protein increased then decreased after radiation. Radiation induced up-regulation of the expression of E2F is due to mostly increase of Phosphorylated retinoblastoma proteins (ppRb). Cyclin Dl, PCNA, CDC2, CDK4 and $p16^{INK4a}$ protein underwent no significant change at any times after irradiation. There was not detected $p21^{WAF1}$ and $p27^{KIP1}$ protein. Cyclin A, B, C mRNA decreased immediately after radiation and then increased at 12 h after radiation. Cyclin Dl mRNA increased immediately and then decreased at 48 h after radiation. After radiation, cyclin E mRNA decreased with the lapse of time. CDK2 mRNA decreased at 3h and increased at eh after radiation. CDK4 mRNA rapidly increased at 6 to 12 h after radiation. There was no change of expression of $p16^{INK4a}$ and not detected in expressin of $p21^{WAF1}$ and $p27^{KIP1}$ mRNA. Conclusion : We suggest that entry into S phase may contribute to apoptosis of HL60 cells induced by irradiation. Increase of ppRb and decrease of pRb protein are related with radiation induced auoptosis of HL60 cells and tosis of HL60 cells induced by irradiation. Increase of ppRb and decrease of PRb protein are related with radiation induced apoptosis of HL60 cells and this may be associated with induction of E2F and cyclinE/CDK2. These results support that $p21^{WAF1}$ and $p27^{KIP1}$ are not related with radiation induced-apoptosis.

• Journal of Yeungnam Medical Science
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• v.22 no.2
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• pp.166-182
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• 2005

Background: Cyclin-dependent kinase (CDK) inhibitors are family of molecules that regulate the cell cycle. The CDKN2, a CDK4 inhibitor, also called p16, has been implicated in human tumorigenesis. The CDKN2 inhibits the cyclin/CDK complexes which regulate the transition from G1 to S phase of cell cycle. There is a previous report that homozygous deletion of CDKN2 region on chromosome 9p21 was detected frequently in astrocytoma, glioma and osteosarcoma, less frequently in lung cancer, leukemia and ovarian cancer, but not detected in colon cancer and neuroblastoma. However, little is known about the relationship between CDKN2 and laryngeal cancer. Therefore this study was initiated to investigate the role of CDKN2 in human laryngeal squamous cell carcinoma development.1) Materials and methods: We used 5 human laryngeal carcinoma cell lines whether they have deletions or losses of CDKN2 gene expression by DNA-PCR or RT-PCR, respectively. We examined 8 fresh frozen human laryngeal cancer tissues to detect the loss of heterozygosity (LOH) of CDKN2. PCR was performed by using microsatellite markers of short arm of human chromosome 9 (D9S126, D9S144, D9S156, D9S161, D9S162, D9S166, D9S171, D9S200 and D9SIFNA). For informative cases, allelic loss was scored if the signal of one allele was significantly decreased in tumor DNA when compared to the same allele in normal DNA. Results: The CDKN2 DNA deletion was observed in 3 cell lines. The CDKN2 mRNA expression was observed in only one cell line, which was very weak. LOH was detected in 7 cases (87.5%). Conclusion: These results suggest that CDKN2 plays a role in the carcinogenesis of human laryngeal squamous cell carcinoma.

• Journal of Environmental Impact Assessment
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• v.30 no.2
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• pp.117-131
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• 2021

Urban development is continuously being carried out to stabilize housing supply. The importance of ecosystem services assessments considering the various urban spatial structures is emerging as land use change in the wake of urban development has impact on the provision of ecosystem services. However, few studies are available as to the effects of land use transition in agricultural land due to urban development on ecosystem services. The purpose of this study is to examine the applicability of decision-making in the urban planning process by analyzing the impact of land use change on ecosystem services due to urban development. Therefore, the scenario was set on before and after the city development, targeting Namyangju Wangsuk Zone 1 and InVEST model was used to compare and analyze changes in value of ecosystem services. Analysis results of ecosystem services before the urban development, it turned out that habitat quality and water yield increased overtime but carbon storage and crop production decreased. Analysis results of ecosystem services after the urban development indicated that all items in ecosystem services by scenario decreased more than in 2018. Among the scenarios of urban development, compact city had the lowest value of water resource supply but had the highest value in terms of habitat quality, carbon storage amount, and crop production. The study results demonstrate that the compact city has positive effects on ecosystem services and is expected to be used as the basic data for supporting policy decision-making in the establishment of future urban development and management plans.

• (The)Study of the Eastern Classic
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• no.32
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• pp.425-441
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• 2008

Most of Korea's Kyungmaedorock(auction book: 競賣圖錄) and pictorial record of exhibitions in the modern times were usually published in the 1930s. Although 1930s were periods of the Great Depression when economic slump continued because of the aftereffect of the slump in the stocks issued by the US in 1929, during this period, Japan began regular continental invasion starting from invasion of the northeastern area of China. To curio dealers, the 1930s were 'boom period of curio transaction' and in urban cultural aspects, the period is evaluated as the one when the first step of modernism was formed. Collection, photo-printing and arrangement of the data related to modern exhibitions including the Auction Book being published at that time are very important because they enable us to know characteristics of fine arts in the transition period from paintings & writings to fine arts in addition to enabling us to revert the circulation history of our paintings & writings and curios. Furthermore, these data will become important data for reconstitution of the circulation history of the Eastern Asia's modern art works. Although the pictorial record of Joseon's Exhibitions of Chinaware and Wooden Works(朝鮮陶磁木工展) is a small and thin one, it records our country's high level chinaware and wooden works. Although we can't know the exact time for 'Joseon's exhibitions of chinaware and wooden works', they are assumed to have been held in Tokyo, Japan in the 1930s and there seems to have been sale of works, too. As such, studies of the books such as the auction book and exhibitions under Japanese imperialism have the first importance in the fact that through which we can examine the course of outflow of our art works to Japan. Furthermore, they can be studies of art-sociology that examine flow and phase of recognition and taste of art works of those days. And from now on, comparative studies of auctions and exhibitions being held in Japan such as Tokyo, Osaka and etc. as well as art markets in Seoul during modern times would also be necessary.

• Information Systems Review
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• v.25 no.4
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• pp.131-159
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• 2023

Recently, amidst the backdrop of the COVID-19 pandemic shifting towards an endemic phase, there has been a rise in discussions and debates about the future of the metaverse. Simultaneously, major metaverse platforms like Roblox have been launching services integrated with generative AI, and Apple's mixed reality hardware, Vision Pro, has been announced, creating new expectations for the metaverse. In this situation where the outlook for the metaverse is divided, it is crucial to diagnose the metaverse from an ecosystem perspective, examine its key ecological features, driving forces for development, and future possibilities for advancement. This study utilized Wang's (2021) Information Ecology Theory (IET) framework, which is representative of ecosystem research in the field of Information Systems (IS), to derive the Metaverse Industrial Ecosystem (MIE). The analysis revealed that the MIE consists of four main domains: Tech Landscape, Category Ecosystem, Metaverse Platform, and Product/Service Ecosystem. It was found that the MIE exhibits characteristics such as digital connectivity, the integration of real and virtual worlds, value creation capabilities, and value sharing (Web 3.0). Furthermore, the interactions among the domains within the MIE and the four characteristics of the ecosystem were identified as driving forces for the development of the MIE at an ecosystem level. Additionally, the development of the MIE at an ecosystem level was categorized into three distinct stages: Narrow Ecosystem, Expanded Ecosystem, and Everywhere Ecosystem. It is anticipated that future advancements in related technologies and industries, such as robotics, AI, and 6G, will promote the transition from the current Expanded Ecosystem level of the MIE to an Everywhere Ecosystem level, where the connection between the real and virtual worlds is pervasive. This study provides several implications. Firstly, it offers a foundational theory and analytical framework for ecosystem research, addressing a gap in previous metaverse studies. It also presents various research topics within the metaverse domain. Additionally, it establishes an academic foundation that integrates concept definition research and impact studies, which are key areas in metaverse research. Lastly, referring to the developmental stages and conditions proposed in this study, businesses and governments can explore future metaverse markets and related technologies. They can also consider diverse metaverse business strategies. These implications are expected to guide the exploration of the emerging metaverse market and facilitate the evaluation of various metaverse business strategies.