• Journal of Life Science
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• v.28 no.11
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• pp.1262-1267
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• 2018

The patchiness of local environments within a habitat is assumed to be a primary factor affecting the spatial patterns of plants. In this study, a randomization procedure was developed to test the null hypothesis that only spatial association with patches determines the spatial patterns of plants. Oplismenus undulatifolius (Ard.) P. Beauv. var. undulatifolius is an herbaceous plant and a member of the genus Oplismenus in the family Poaceae. Oplismenus hirtellus subsp. undulatifolius occurs in temperate, subtropical, and tropical areas of the world. The spatial pattern of O. undulatifolius var. undulatifolius was analyzed using dispersion indices in different sizes of plots according to several patchiness indexes, population uniformity, or aggregation. Population densities (D) at Mt. Hanwoo varied from 0.453 to 4.375, with a mean of 2.387. The small and mid-sized plots ($2m{\times}2m$, $2m{\times}4m$, $4m{\times}4m$, $4m{\times}8m$, and $8m{\times}8m$) of O. undulatifolius var. undulatifolius were aggregated in the forest community. However, O. undulatifolius var. undulatifolius was uniformly distributed in three large plots ($8m{\times}16m$, $16m{\times}16m$, and $16m{\times}32m$). The greatest mean crowding ($M^*$) and patchiness index (PAI) showed positive values. Aggregation is mainly caused by environmental factors. Many plants on Mt. Hanwoo are being disturbed by climbers, which is preventing these plants from inhabiting their realized niches on Mt. Hanwoo.

• Journal of Life Science
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• v.32 no.8
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• pp.647-658
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• 2022

Particulate matter (PM) is known to be involved in the onset and progression of various diseases by promoting oxidative and inflammatory reactions as air pollutants containing various small particles that are harmful. In this study, the protective efficacy of herbal medicines was evaluated in human corneal epithelial cells (hCECs) to select natural products that can protect the eye, the primary organ directly exposed to external pollutants from PM. As a result, five candid ate herbal medicines [Cheonmundong, Asparagus Rhizome; Seokchangpo, Aciru Gramineri Rhizoma; Hwangryeon, Coptidis Rhizoma; Gamgug, Chrysanthemi Indici Flos; and Geumjanhwa (Marigold flower petals)] which showed inhibitory efficacy on PM_2.5-induced cytotoxicity, were selected from among 12 candidate herbal medicines. To evaluate the antioxidant activity of these candidate substances, the reactive oxygen species (ROS) scavenging ability was investigated, and it was found that the extracts of Seokchangpo, Cheonmundong and Hwangryeon showed a significant inhibitory effect on PM_2.5-induced ROS production, which was correlated with the preservation of mitochondrial activity. In addition, it was confirmed that they could block DNA damage caused by PM_2.5 through analysis of 8-hydroxy-2'-deoxyguanosine generation and phosphorylated-H2A histone family member X (γ- H2AX) expression. Furthermore, the increase in inflammasome activity and inflammatory response in PM_2.5-treated hCECs was also canceled in the presence of these extracts. Although additional studies are needed, the results of this study will be used as primary data to find novel natural compounds that protect hCECs from PM.

• Korean Journal of Schizophrenia Research
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• v.23 no.1
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• pp.1-7
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• 2020

Objectives: This study aimed to identify factors affecting the duration of untreated psychosis (DUP) in patients with schizophrenia spectrum disorder. Methods: Six-hundred patients with schizophrenia spectrum disorder were recruited from mental health welfare centers in Gwangju Metropolitan City and Gyeonggi-do. Subjects were categorized into two groups according to median DUP. Demographic and clinical characteristics were compared between the two groups. Results: The mean DUP was 80.8 weeks, and the median DUP was 15.9 weeks. Patients with Medicaid, higher age, and longer duration of the schizophrenia prodrome were more likely to have a longer DUP. The DUP was shorter in patients who were consulted by family/relatives prior to treatment. Patients visiting university hospitals were more likely to have a shorter DUP compared with those visiting psychiatric clinics or small-sized mental hospitals, i.e., with less than 100 beds. A multivariate regression analysis showed that the duration of the prodrome was a factor that significantly affected DUP. Conclusion: The vulnerable group of patients with schizophrenia with a long DUP should be monitored closely. Moreover, it is necessary to develop a strategy to identify patients who have an insidious course of psychosis to reduce the DUP.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.6
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• pp.444-450
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• 2008

Purpose: The aim of this study was to evaluate the usefulness of whole body positron emission tomography (PET) using $^{18}F-fluorodeoxyglucose$ ($^{18}F-FDG$) for cancer screening in asymptomatic subjects. Materials and Methods: The subjects were 1,762 men and 259 women who voluntarily underwent $^{18}F-FDG$ PET for cancer screening as a part of a routine health examination. Final diagnosis was decided by other diagnostic studies, pathological results or clinical follow-up for 1 year. Results: Of 2,021 subjects, 40 (2.0%) were finally proved to have cancer. Abnormal focal $^{18}F-FDG$ uptake suggesting malignancy was found in 102 subjects (5.0%). Among them, 21 subjects (1.0%) were proved to have cancer. Other tests in the routine health examination could not find 9 of 21 cancers (42.9%) detected by PET. The sensitivity, specificity, positive predictive value, and negative predictive value of PET for cancer screening were 52.5%, 95.9%, 20.6%, and 99.0%, respectively. Pathologies of cancers missed on PET were adenocarcinoma (n = 9; 3 colon cancers, 3 prostate cancers, 2 stomach cancers, and 1 rectal cancer), differentiated thyroid carcinoma (n = 6), bronchioalveolar cell carcinoma (n = 2), urinary bladder cancer (n = 1), and melanoma (n = 1). More than half of cancers which were not detected by PET were smaller than 1 cm in diameter. Conclusion: $^{18}F-FDG$ PET might be useful for cancer screening in asymptomatic subjects due to its high specificity and negative predictive value and playa supplementary role to the conventional health check-up, but it could not replace due to limited sensitivity for urological cancers, small-sized tumors and some hypometaboic cancers.

• Parasites, Hosts and Diseases
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• v.53 no.2
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• pp.209-213
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• 2015

The present study was performed to survey the infection status of zoonotic intestinal trematode (ZIT) in stray cats from 5 major riverside areas in the Republic of Korea. Total 400 stray cats were captured with live-traps in riverside areas of Seomjingang ('gang' means river) (203 cats) from June to October 2010, and of Yeongsangang (41), Nakdonggang (57), Geumgang (38), and Hangang (61 cats) from June to October 2011, respectively. Small intestines resected from cats were opened with a pair of scissors in a beaker with 0.85% saline and examined with naked eyes and under a stereomicroscope. More than 16 ZIT species were detected in 188 (92.6%) cats from Seomjingang areas, and the number of worms recovered was 111 per cat infected. In cats from riverside areas of Yeongsangang, Nakdonggang, Geumgang, and Hangang, more than 9, 8, 3, and 5 ZIT species were recovered, and the worm burdens were 13, 42, 11, and 56 specimens per infected cat, respectively. As the members of family Heterophyidae, more than 10 species, i.e., Metagonimus spp., Pygidiopsis summa, Heterophyes nocens, Stellantchasmus falcatus, Heterophyopsis continua, Acanthotrema felis, Centrocestus armatus, Procerovum varium, Cryptocotyle concava, and Stictodora lari, were recovered. More than 5 species of echinostomes, i.e., Echinostoma hortense, Echinochasmus japonicus, Echinochasmus sp., Echinoparyphium sp., and unidentified larval echinostomes, were collected. Plagiorchis spp. were detected in cats from areas of Seomjingang and Yeongsangang. From the above results, it has been confirmed that stray cats in 5 major riverside areas of Korea are highly infected with various species of ZITs.

• Plant Breeding and Biotechnology
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• v.5 no.4
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• pp.334-343
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• 2017

Eclipta prostrata and E. alba are annual herbal medicinal plants and have been used as Chinese medicinal tonics. Both species are widely distributed in tropical and subtropical regions as well as in Korea. Both species have similar morphological features but E. alba has smoother leaf blade margins compared with E. prostrata. Although both species are utilized as oriental medicines, E. prostrata is more widely used than E. alba. Morphological semblances have confounded identification of either species. Here, we report the complete chloroplast genomes of both species to provide an authentication system between the two species and understand their diversity. Both chloroplast genomes were 151,733-151,757 bp long and composed of a large single copy (83,285-83,300 bp), a small single copy (18,283-18,346 bp), and a pair of inverted repeats (25,075-25,063 bp). Gene annotation revealed 80 protein coding genes, 30 tRNA genes and four rRNA genes. A phylogenetic analysis revealed that the genus Eclipta is grouped with Heliantheae tribe species in the Asteraceae family. A comparative analysis verified 29 InDels and 58 SNPs between chloroplast genomes of E. prostrata and E. alba. The low chloroplast genome sequence diversity indicates that both species are really close to each other and are not completely diverged yet. We developed six DNA markers that distinguish E. prostrata and E. alba based on the polymorphisms of chloroplast genomes between E. prostrata and E. alba. The chloroplast genome sequences and the molecular markers generated in this study will be useful for further research of Eclipta species and accurate classification of medicinal herbs.

• Journal of Agricultural Extension & Community Development
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• v.21 no.3
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• pp.53-89
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• 2014

Immigrant farmers work in various social and economic fields of activity, settling in their rural community. In this study, I inquired into the way of acting of immigrant farmers, based on the texts which were made in the precedent studies. The texts were transcriptions that were made by interviews with immigrant farmers. I classified immigrant farmers' activities into 8 groups that were related to; farming, nonfarm business, off-farm business, volunteering, participating in community organization, lifelong learning, leisure and social interaction in everyday life. And, I tried to capture the characteristics and meanings of those activities. The implications from this analysis are as followings: 1) most of immigrant farmers have small family farm so that they need nonfarm or off-farm jobs, 2) pluri-acivities of immigrant farm households can contribute to their community's economic viability, 3) their economic activities should be observed carefully in the perspective of self-help approach in community development as well as farm households' livelihood strategy, 4) immigrant farmers have many difficulties to participate in community, nevertheless community participation will improve the social capital, 5) gender-sensitive policy should be developed.

• Journal of the Korean Wood Science and Technology
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• v.48 no.4
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• pp.527-547
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• 2020

Fish pathogens cause not only economic damages to fish farming but also infectious pathogens known as a zoonotic agent. Since the continued use of antibiotics to control fish pathogens entails side effects, materials of natural origin need to be developed. The purpose of this study is to discover coniferous essential oils with excellent antibacterial effects in order to develop antibiotic alternatives. We have extracted essential oils using hydro-distillation from the leaves of Abies holophylla, Pinus thunbergii, Pinus parviflora, Tsuga sieboldii, and Pinus rigitaeda, which are all Pinaceae family. And, we have evaluated antibacterial activity with the extracted essential oils against Edwardsiella tarda, Photobacterium damselae, Streptococcus parauberis, and Lactococcus garvieae, which are fish pathogens. As a result, the essential oils from A. holophylla and P. thunbergii showed the selectively strong antibacterial activity against E. tarda and P. damselae, which are gram-negative bacteria. From GC-MS analysis, it was identified that main component of A. holophylla essential oils are (-)-bornyl acetate (29.45%), D-limonene (20.47%), and camphene (11.73%), and that of P. thunbergii essential oils is α-pinene (59.81%). In addition, we found three compounds: neryl acetate, (-)-borneol, and (-)-carveol, which are oxygenated monoterpenes. These exist in a very small amount but exhibit the same efficacy as essential oil. Therefore, we expect that A. holophylla and P. thunbergii essential oils having excellent growth inhibitory effect against gram-negative fish pathogens can be used as biological products such as feed additives and fishery products.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.3
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• pp.111-118
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• 2023

MXene, a two-dimensional transition metal carbide or nitride, has recently attracted much attention as a lightweight and flexible electromagnetic shielding material due to its high electrical conductivity, good mechanical strength and thermal stability. In particular, the Ti-based MXene, Ti₃C₂T_x and Ti₂CT_x are reported to have the best electrical conductivity and electromagnetic shielding properties in the vast MXene family. Therefore, in this study, Ti₃C₂T_x and Ti₂CT_x films were prepared by vacuum filtration using Ti₃C₂T_x and Ti₂CT_x dispersions synthesized by interlayer metal etching and centrifugation of Ti₃AlC₂ and Ti₂AlC. The electrical conductivity and electromagnetic shielding efficiency of the films were measured after heat treatment at high temperature. Then, X-ray diffraction and photoelectron spectroscopy were performed to analyze the structural changes of Ti₃C₂T_x and Ti₂CT_x films after heat treatment and their effects on electromagnetic shielding. Based on the results of this study, we propose an optimal structure for an ultra-thin, lightweight, and high performance MXene-based electromagnetic shielding film for future applications in small and wearable electronics.

• Research in Plant Disease
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• v.15 no.2
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• pp.63-67
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• 2009

Rice stripe virus (RSV) is one of Tenuivirus Group, which is carried by small brown planthopper. There is an outbreak of RSV in South Korea at 20Ot, and 2007. The infection caused by RSV had been investigated on weeds around the rice cultivated areas 13 region and 26 site including Jeonbuk Buan and Chungnam Seocheon. There have a doubt as to alternate host of RSV is total 15 Family and 50 Species including Gramineae 24 species of Duksaepul (Alopecurus aequalis), H. sativum var. vulgare etc.. There is identified the infected RSV in Festuca myuros, Alopecurus aequalis, Hordeum sativum var. vulgare, Trisetum bifidum, Echinochloa crus-galli var. crus-galli, Digitaria ciliaris among this species. Deulmuksae is the overwintering exotic weed which sprout in Autumn and wither in Spring and commonly growed as green manure crop or cover crop. In order to identify the infection rate furthermore, 111 samples which were collected at Buan Gyehwa-myeon region, and 50 samples from Seocheon Maseo-myeon in June, 2008, were ELISA tested. The results are 32 positives from Buan, 28.8% infection rate, 8 positives from Seocheon 16.0% infection rate. RSV infection of Deulmuksae is not reported currently, and follow report first describes the Deulmuksae as an alternate host of RSV.