• Title/Summary/Keyword: double-well potential

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Induced Polarization Surveys of Contaminants and Introduction to Case Studies (오염원에 대한 유도분극탐사 반응 및 사례 소개)

  • Kim, Bitnarae;Caesary, Desy;Yu, Huieun;Cho, AHyun;Song, Seo Young;Cho, Sung Oh;Joung, Inseok;Nam, Myung Jin
    • Journal of Soil and Groundwater Environment
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    • v.25 no.2_spc
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    • pp.86-100
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    • 2020
  • Analyzing and monitoring environmental contaminants based on geophysical exploration techniques have become important and it is now widely applied to delineate spatial distribution geophysical characteristics in wide area. Among the techniques, induced polarization (IP) method, which measures polarization effects on electrical potential distribution, has drawn much attention as an effective tool for environmental monitoring since IP is sensitive to changes in biochemical reactions. However, various reactions stemming from the presence of multiple contaminants have greatly enhanced heterogeneity of polluted sites to result in highly variable electrical characteristics of the site. Those contaminants influence chemical and physical state of soil and groundwater to alter electrical double layer, which in turn influences polarization of the media. Since biochemical reactions between microbes and contaminants result in various IP effects, IP laboratory experiments were conducted to investigate IP responses of the contaminated soil samples under various conditions. Field IP surveys can delineate the spatial distribution of contamination, while providing additional information about electrical properties of a target medium, together with DC resistivity. Reviewing IP effects of contaminants as well as IP surveys can serve as a good starting point for the application of IP survey in site assessment for environmental remediation.

Particle Filtration Efficiency Testing of Sterilization Wrap Masks

  • Chau, Destiny F.;O'Shaughnessy, Patrick;Schmitz, Michael L.
    • Journal of Preventive Medicine and Public Health
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    • v.54 no.1
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    • pp.31-36
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    • 2021
  • Objectives: Non-traditional materials are used for mask construction to address personal protective equipment shortages during the coronavirus disease 2019 (COVID-19) pandemic. Reusable masks made from surgical sterilization wrap represent such an innovative approach with social media frequently referring to them as "N95 alternatives." This material was tested for particle filtration efficiency and breathability to clarify what role they might have in infection prevention and control. Methods: A heavyweight, double layer sterilization wrap was tested when new and after 2, 4, 6, and 10 autoclave sterilizing cycles and compared with an approved N95 respirator and a surgical mask via testing procedures using a sodium chloride aerosol for N95 efficiency testing similar to 42 CFR 84.181. Pressure testing to indicate breathability was also conducted. Results: The particle filtration efficiency for the sterilization wrap ranged between 58% to 66%, with similar performance when new and after sterilizing cycles. The N95 respirator and surgical mask performed at 95% and 68% respectively. Pressure drops for the sterilization wrap, N95 and surgical mask were 10.4 mmH2O, 5.9 mmH2O, and 5.1 mmH2O, respectively, well below the National Institute for Occupational Safety and Health limits of 35 mmH2O during initial inhalation and 25 mmH2O during initial exhalation. Conclusions: The sterilization wrap's particle filtration efficiency is much lower than a N95 respirator, but falls within the range of a surgical mask, with acceptable breathability. Performance testing of non-traditional mask materials is crucial to determine potential protection efficacy and for correcting misinterpretation propagated through popular media.

Inhibition of Pathogenic Bacteria and Fungi by Natural Phenoxazinone from Octopus Ommochrome Pigments

  • Lewis-Lujan, Lidianys Maria;Rosas-Burgos, Ema Carina;Ezquerra-Brauer, Josafat Marina;Burboa-Zazueta, Maria Guadalupe;Assanga, Simon Bernard Iloki;del Castillo-Castro, Teresa;Penton, Giselle;Plascencia-Jatomea, Maribel
    • Journal of Microbiology and Biotechnology
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    • v.32 no.8
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    • pp.989-1002
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    • 2022
  • Cephalopods, in particular octopus (Octopus vulgaris), have the ability to alter their appearance or body pattern by showing a wide range of camouflage by virtue of their chromatophores, which contain nanostructured granules of ommochrome pigments. Recently, the antioxidant and antimicrobial activities of ommochromes have become of great interest; therefore, in this study, the pH-dependent redox effect of the extraction solvent on the antioxidant potential and the structural characterization of the pigments were evaluated. Cell viability was determined by the microdilution method in broth by turbidity, MTT, resazurin, as well as fluorescence microscopy kit assays. A Live/Dead Double Staining Kit and an ROS Kit were used to elucidate the possible inhibitory mechanisms of ommochromes against bacterial and fungal strains. The results obtained revealed that the redox state alters the color changes of the ommochromes and is dependent on the pH in the extraction solvent. Natural phenoxazinone (ommochromes) is moderately toxic to the pathogens Staphylococcus aureus, Bacillus subtilis, Salmonella Typhimurium and Candida albicans, while the species Pseudomonas aeruginosa and Pseudomonas fluorescens, and the filamentous fungi Aspergillus parasiticus, Alternaria spp. and Fusarium verticillioides, were tolerant to these pigments. UV/visible spectral scanning and Fourier- transform infrared spectroscopy (FTIR) suggest the presence of reduced ommatin in methanol/ HCl extract with high intrinsic fluorescence.

Comparative analysis of active components and antioxidant activities of Brussels sprouts (Brassica oleracea var. gemmifera) and cabbage (Brassica oleracea var. capitata)

  • Kwan Woo Jeon;Min Gun Kim;Su Hyeong Heo;Kyung Hwan Boo;Jae-Hoon Kim;Chang Sook Kim
    • Journal of Applied Biological Chemistry
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    • v.65 no.4
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    • pp.413-419
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    • 2022
  • The applicability of Brussels sprouts, which are widely cultivated in Jeju, as a functional biomaterial in the cosmetics and food industries is investigated. The active ingredients (total phenols and flavonoids, β-carotene, vitamin C, free sugar, minerals, glucosinolates, and isothiocyanates) and antioxidant activities of 70% ethanol extracts of Brussels sprouts and cabbage were analyzed. The total phenol, flavonoid, vitamin C, and β-carotene contents of Brussels sprouts were approximately 36%, 2.5 times, 2.3 times, and 65% higher than those of cabbage, respectively. The total free sugar content of Brussels sprouts was 58%-72% lower than that of cabbage. The K content was the highest among the other minerals, and there was little difference between the two samples. The Na content was approximately three times higher in cabbage than in Brussels sprouts. The total glucosinolate content of Brussels sprouts was 34.5 mol SE/g DW, twice that of cabbage. The sinigrin content of Brussels sprouts was thrice (10.06 μmol/g DW) that of cabbage. The isothiocyanate (sulforaphane, I3C) content in Brussels sprouts was double that of cabbage. The antioxidant activity of Brussels sprout extract was 2.5 to 2.8 times higher in 1,1-Diphenyl-2-picrylhydrazyl radical scavenging capacity and 3.3 to 3.6 times higher in 2,2'-Azino-bis(3-ethybenzothiazoline-6-sulfonic acid) radical scavenging capacity than those of cabbage extract. These are important basic data for the study of glucosinolates and isothiocyanates, which have anticancer activity, as well as antioxidant-related substances of Brussels sprout, which has high potential for use as a biomaterial in functional foods and cosmetics.

The Poetics of Overcoming: Christopher Dewdney's Transhumanism and Dionisio D. Martinez's Transnational Cultural Contamination

  • Kim, Youngmin
    • Journal of English Language & Literature
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    • v.57 no.6
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    • pp.1089-1109
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    • 2011
  • In an attempt to demonstrate in context of Nietzsche's "overman" (ubermensch) and Heidegger's "Being-in-the-World" (Dasein) the collective human efforts to overcome humanism in crisis, I will provide the ground for the poetics of overcoming, the ground which are based upon the double movements of transhumanism and transnationalism. For this purpose, I will turn to the theories of two distinctive poets who reveal and disreveal their truths about the subjecthood or the subjectivity in terms of overcoming: Christopher Dewdney for posthuman transhumanity and Dionisio D. Martinez for transnational cultural contamination Transhumanism represented by Christopher Dewdney manifests an interfusion of outside and inside, thereby collapsing the boundary between the mind and the world, and provides a breakthrough from the limitedly defined mind to the transhuman perspective of overcoming by using terminalogy and techniques from science and technology. The emerging transhumanism reflects the growing interdependence between humans and bio technologies, and suggests a potential improvement of human beings. The main argument of transhumanism is that we humans can and should continue to develop in all possible directions, by overcoming our human limitations by shedding the body and having the disembodied consciousness which will liberate our mind. Kwame Anthony Appiah's "cultural contamination" is another form of overcoming as well as a way to otherness, a counter-ideal of cultural purity which sustains authentic culture, reversing the traditional binary opposition between enriching authenticity and threatening hybridization. Dionisio Martinez's poetry sublimates the negative side of Appiah's concept of contamination, by redeeming the value of the Appiah's list of the ideal of contamination such as hybridity, impurity, intermingling, the transformation that comes of new and unexpected combinations of human beings, a bit of this and a bit of that is how newness enters the world. When a poetic subject is doubly exiled and doubly homeless away from his/her native homeland and home of native language, one has no more identification with the authentic culture of both home and away, but rather anticipates a new identity as a transnational subject to cross the bridge beyond cultural authenticity and to enter into the field of cultural contamination.

Suitability Grouping System of Paddy Soils for Multiple Cropping -Part I: Basic Experiments (다모작(多毛作)을 위한 답토양(畓土壤) 적성등급(適性等級) 구분(區分) -제(第) 1 보(報) : 기초시험(基礎試驗))

  • Jung, Yeun-Tae;Park, Eun-Ho;No, Yeong-Pal;Um, Ki-Tae
    • Korean Journal of Soil Science and Fertilizer
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    • v.19 no.3
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    • pp.211-216
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    • 1986
  • To establish a suitability grouping system of paddy soils for double or multiple cropping with rice which is intensively practiced in the southern parts of Korea, a few basic experiments were carried out for two years. The results are summarized as follows; 1. The potential productivities of the paddy soils which were tested without any fertilizer in the pots of subsoil samples by the double cropping of rice and other upland crops were resulted that the soils of "Moderately well drained" fine silty textured were the highest while the soils of "Poorly drained" sandy were the lowest, and the productivities could be clearly comparable according to the differences of soil conditions. 2. The decomposability of organic matter also was higher in the soils of "Moderately well drained" than the "Imperfectly drained". The coarse loamy and coarse silty textured soils were high in the upland condition and in the early stages of submerging while the fine loamy and fine silty textured soils were high at the late stage of submerging in the rates of organic matter decomposition. 3. The days to be reached to tillable condition after rainfall in fine loamy textured soils were about 5 days earlier than the clayey soils. The period of tillable condition of fine clayey soils with "Moderately well drained" was the longest and that of the fine loamy textured soils was the shortest. But the soils with "Imperfectly drained" were not clear among soil textural classes. 4. The lower the ground water table the higher was the productivity indices. The variation of ground water table in the medium textured soils was higher than the both of coarse and fine textured soils among "Moderately well drained". But it was observed the opposite in the soils of "Imperfectly drained".

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Review of Domestic Research Trends on Layered Double Hydroxide (LDH) Materials: Based on Research Articles in Korean Citation Index (KCI) (이중층수산화물(layered double hydroxide, LDH) 소재의 국내 연구동향 리뷰: 한국학술지인용색인(KCI)에 발표된 논문을 대상으로)

  • Seon Yong Lee;YoungJae Kim;Young Jae Lee
    • Economic and Environmental Geology
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    • v.56 no.1
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    • pp.23-53
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    • 2023
  • In this review paper, previous studies on layered double hydroxides (LDHs) published in the Korean Citation Index (KCI) were examined to investigate a research trend for LDHs in Korea. Since the first publication in 2002, 160 papers on LDHs have been published until January 2023. Among the 31 academic fields, top 5 fields appeared in the order of chemical engineering, chemistry, materials engineering, environmental engineering, and physics. The chemical engineering shows the highest record of published paper (71 papers) while around 10 papers have been published in the other four fields. All papers were reclassified into 15 research fields based on the industrial and academic purposes of using LDHs. The top 5 in these fields are in order of environmental purification materials, polymer catalyst materials, battery materials, pharmaceutical/medicinal materials, and basic physicochemical properties. These findings suggest that researches on the applications of LDH materials in the academic fields of chemical engineering and chemistry for the improvement of their functions such as environmental purification materials, polymer catalysts, and batteries have been being most actively conducted. The application of LDHs for cosmetic and agricultural purposes and for developing environmental sensors is still at the beginning of research. Considering a market-potential and high-efficiency-eco-friendly trend, however, it will deserve our attention as emerging application fields in the future. All reclassified papers were summarized in our tables and a supplementary file, including information on applied materials, key results, characteristics and synthesis methods of LDHs used. We expect that our findings of overall trends in LDH research in Korea can help design future researches with LDHs and suggest policies for resources and energies as well as environments efficiently.

.A Study on Parents' Transnational Educational Passion in the Tendency of Globalization : The Potential and Limitations of Educational Nomadism (세계화의 흐름에서 학부모의 초국가적 교육열 - 교육노마디즘의 가능성과 한계를 중심으로 -)

  • Kim, So-Hee
    • Korean Journal of Culture and Arts Education Studies
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    • v.5 no.1
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    • pp.97-147
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    • 2010
  • Under the recent trend of globalization, a new proposal on education has not been able to avoid the request for multi-cultural trend. Furthermore, education has been exposed to circumstances which are far different from the previous situations in which global cooperation and intercultural understanding have been more emphasized. 'Educational Nomadism'is a metaphor of creating new value and significance of education. In fact, transnational education which could be a crisis and opportunity at the same time has recently been the mainstream throughout the world. In terms of education, Korea has encountered base hollowing-out in which excessive dependence on the US education and autonomous education coexist. In fact, the world has spent a lot of time and money to have better educational background on a resume through redundant expense by the government and parents. Under this critical situation, it's urgent to change Korea's modern education into a creative educational system in connection with an advanced foreign educational system and further develop the advantage of Korea's education. A parent's investment in his/her child is a support to create new culture as well as an assistance for hope and better future of Korean education. A new direction of parents' education fever that has opened a door to global communitas can stir up infinite potential through which the flow of education fever can be changed to the resources of new civilization. The global cooperation and efforts for communitas means the communication with this world. Through this communication, the culture in which people are forced to zero-sum competition can leap into the education for change of civilization which creates pleasure of self sufficiency and donation.

Review of property and utilization of oil crop for biodiesel (바이오디젤 원료작물의 기름 및 지방산 특성에 따른 활용방안 고찰)

  • Jang, Young-Seok;Kim, Kwang-Soo;Lee, Yong-Hwa;Cho, Hyeon-Jun;Suh, Sae-Jung
    • Journal of Plant Biotechnology
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    • v.37 no.1
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    • pp.25-46
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    • 2010
  • The demand for fuel and energy resources continues to grow due to increased consumption and emerging economies in all parts of the world. With this increase in demand, crude oil prices in the international market has jumped dramatically. Global warming, which is a consequence of increasing greenhouse gas (GHG) emissions, has become scientific, social, and political concerns. To cope with global warming and energy crisis, cost-competitive biofuels are urgently needed. In addition, development of an infrastructure, which supplies energy stably and diversifies energy resources, as well as new cost-saving technologies should be developed to reduce the costs of producing biofuels. Due to high oleic acid content, rapeseed (Brassica napus L.) is currently the potential feedstock for biodiesel production in temperate zone region and the production and use of rapeseed oil is already commercialized in Europe. In Korea double-cropping (rice and rapeseed) became more prevalent because it reduces competitions from land constraints. Production of rapeseed as a biodiesel feedstock may reduce the influence of rising oil prices and nation's dependence on imported petroleum and increase job opportunities and farm incomes.

Histopathologic Features and CD5+ B-lymphocyte Expression in the Experimental Allergic Neuritis (실험적 자가면역성 말초신경염에서의 조직병리적 병변 및 CD5+ B-림프구의 발현)

  • Cho, Joong-Yang;Choi, Won-Jun;Kim, Sung-Hun;Sung, Jung-Joon;Kim, Ho-Jin;Park, Kyung-Seok;Choi, Ki-Young;Kim, Hyun-Jung;Lee, Kwang-Woo
    • Annals of Clinical Neurophysiology
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    • v.1 no.2
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    • pp.91-98
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    • 1999
  • Background : The pathogenesis of acute inflammatory demyelinating polyradiculoneuropathy (AIDP), Guillain Barre syndrome (GBS) is not clear, but it has been known that the immune mechanisms play an important role. Authors performed this study to establish an animal model of experimental allergic neuritis (EAN) by immunizing the myelin components of peripheral nerves and to understand the electrophysiological and histopathological features as well as the ${CD_5}^+$ B-lymphocyte changes in peripheral bloods in the EAN models. Methods : Lewis rats weighing 150-200 gm were injected subcutaneously in soles two times with total myelin, P0, P1, or P2 proteins purified from the bovine cauda eguina. The EAN induction was assessed by evaluating clinical manifestations. The electrophysiological and histopathological features were studied as routine methods. The ${CD_5}^+$ Blymphocytes were double stained using monoclonal FITC conjugated anti-rat CD45RA and R-PE conjugated anti-rat ${CD_5}^+$ antibodies and calculated using a fluorescence activated cell sorter (FACS). Results : The EAN animal models were established. In two out of five, in one out of two, in none out of three, and in none out of one Lewis rats injected with purified total myelin, P0, P1, P2 proteins respectively, They showed slow spontaneous motor activity and weak resistance against pulling back by tails. The typical electrophysiological and histologic findings in total protein and P0 induced EAN animal models were the decreased conduction velocity, the decreased compound muscle action potential (CMAP) amplitude and the dispersion phenomenon. The perivascular infiltrates of lymphocytes with focal demyelinating process were found in light microscopy. The ${CD_5}^+$ B-lymphocyte expression in three EANs were 2.38%, 3.50% 2.50%, which were not significantly increased, compared with those in normal controls. Conclusion : The EAN animal models were successfully established by injecting the total myelin and P0 myelin and they showed electrophysiological and histological features typical of demyelinating process. However they did not show an increased expression of ${CD_5}^+$ B-lymphocyte in peripheral bloods which could be indirect evidence of humoral autoimmunity.

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