• Bulletin of the Korean Chemical Society
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• v.27 no.11
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• pp.1747-1751
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• 2006

The dinuclear tetraazadiphenol macrocyclic nickel(II) complexes [$Ni_2$([20]-DCHDC)]$Cl_2$ (I), [$Ni_2$([20]-DCHDC)]$(ClO_4)_2{\cdot}2CH_3CN $ (II(b)) and [$Ni_2$([20]-DCHDC)$(NCS)_2$] (III) {$H_2$[20]-DCHDC = 14,29-dimethyl-3,10,18,25-tetraazapentacyclo-[25,3,1,$0^{4,9}$,$1^{12,16}$,$0^{19,24}$]ditriacontane-2,10,12,14,16(32),17,27(31), 28,30-decane-31,32-diol} have been synthesized by self-assembly and characterized by elemental analyses, conductances, FT-IR and FAB-MS spectra, and single crystal X-ray diffraction. The crystal structure of II(b) is determined. It crystallizes in the monoclinic space group P2(1)/c. The coordination geometries around Ni(II) ions in I and II(b) are identical and square planes. In complex III each Ni(II) ion is coordinated to $N_2O_2$ plane from the macrocycle and N atoms of NCS- ions occupying the axial positions, forming a square pyramidal geometry. The nonbonded Ni…Ni intermetallic separation in the complex II(b) is 2.8078(10) $\AA$. The FAB mass spectra of I, II and III display major fragments at m/z 635.1, 699.4 and 662.4 corresponding to [$Ni_2$([20]-DCHDC)(Cl + 2H)]$^+$, [$Ni_2$([20]-DCHDC)$(ClO_4\;+\;2H)]^+$ and [$Ni_2$([20]-DCHDC)(NCS) + 6H]$^+$, respectively.

• Korean Chemical Engineering Research
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• v.54 no.2
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• pp.181-186
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• 2016

Recently, there are many efforts focused on development of more economical non-fluorinated membranes for use in PEMFCs (Proton Exchange Membrane Fuel Cells). In this study, characteristics of sulfonated Poly(ether ether ketone) (sPEEK) were compared according to degrees of sulfonation (DS), relative humidity, cell temperatures at PEMFC operation condition. I-V polarization curve, hydrogen crossover, electrochemical surface area, membrane resistance and charge transfer resistance were measured. sPEEK membrane showed high performance at high DS, high temperature and high relative humidity, in particular, performance of sPEEK membrane decreased largely due to low ionic conductivity at low DS and low relative humidity.

• Journal of Hydrogen and New Energy
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• v.32 no.5
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• pp.315-323
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• 2021

The air-cooled proton exchange membrane fuel cells (PEMFC) stacks, which is widely used in small-sized PEMFC, have a problem in that durability is weaker than that of the water-cooled type. Because the cathode is open to the atmosphere and the structural problem of the air-cooled stack, which is difficult to maintain airtightness, is highly likely to form a hydrogen/air boundary during start-up/shut-down (SU/SD). Through the accelerated durability evaluation of the 20 W air-cooled PEMFC stack, the purpose of this study was to find out the cause of the degradation of the stack and to contribute to the improvement of the durability of the air-cooled PEMFC stack. In this study, it was possible to evaluate durability in a relatively short time by reducing 20-30% of initial performance by repeating SU/SD 1,000 to 1,200 times on an air-cooled PEMFC stack. After disassembling the stack, each cell was divided into two and the performance analysis showed that the electrode degradation was more severe in the anode outlet membrane electrode assembly (MEA), which facilitates air inflow as a whole, than in the inlet MEA. It was shown that the cathode Pt was dissolved/precipitated to deteriorate the polymer ionomer inside the membrane.

• Korean Chemical Engineering Research
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• v.60 no.1
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• pp.20-24
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• 2022

In the process of long-term use of PEMFC (Proton Exchange Membrane Fuel Cells), chemical degradation of membrane electrode assembly (MEA) occurs due to corrosion of stack elements and contamination of supply gas. In this study, we investigated whether chemically degraded MEA can be recovered by acid washing. The performance was measured and compared in a PEMFC cell after contamination with iron ions and washing with an aqueous sulfuric acid solution. The performance was reduced by about 25% by 0.5 ppm iron ion contamination, and 97.1% performance recovery was possible by washing of 0.15 M sulfuric acid. The membrane resistance was increased due to iron ion contamination of the polymer membrane, and the ionic conductivity was restored by washing the iron ions from the membrane while minimizing the loss of the electrode catalyst by washing with a low-concentration sulfuric acid aqueous solution. The possibility of solving the decrease in durability caused by chemical contamination of PEMFC MEA by the acid washing was confirmed.

• Korean Journal of Veterinary Service
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• v.46 no.2
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• pp.115-122
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• 2023

This study was performed to investigate the distribution of mosquito vectors related to the zoonotic disease in Daejeon. Samples were taken using a blacklight trap once a month from March to November 2021 at the slaughterhouse in Daejeon. A total of 820 mosquitoes were captured and classified into 5 genera and 8 species. Among the collected mosquitoes, 319 (38.9%) and 295 (35.93%) were Aedes vexans nipponii and Culex pipiens pallens, respectively, making them the dominant species. The overall number of mosquitoes collected started to increase from May and reached the largest value of 329 (40.12%) in June. Trapped mosquitoes are created 72 pools by environmental condition and by species. The pools were tested by PCR methods for 7 zoonotic pathogens. Flavivirus-positive products were confirmed by DNA sequencing. Japanese encephalitis viruses were detected in 3 pools collected from cow lairage (Culex pipiens pallens) in May, cow by-product processing room (Aedes vexans nipponii) in June and cow lairage (Mansonia uniformis) in June. Culex flavivirus were detected in 4 pools. Based on the results of this study, it is considered that continous surveillence of mosquitoes in livestock assembly facilities (slaughterhouse) should be performed for controlling mosquito populations and mediating disease spread by mosquitoes.

• Korean Journal of Occupational Health Nursing
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• v.20 no.2
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• pp.185-194
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• 2011

Purpose: Global shortages in nursing and strong demand for nursing services provided Korean nurses with more overseas employment opportunities, especially in the developed countries such as the United States and Canada. The purpose of this study was to explore the ageing experiences of the Korean nurses dispatched to Germany in the 1960s and 1970s. Methods: The researcher interviewed 10 Korean nurses living in four cities in Germany. Interviews were performed twice in January and July, 2010, and the data, in the form of field notes and interview transcripts, were analyzed using the Agar's (1980) ethnographic method. Results: The ageing experiences of the participants can be summarized into three theme stages: coming upon old age, reluctantly realizing getting old, and finally accepting being old. The first stage is characterized by 'wiring money to homeland all throughout youth', second 'still feeling like a stranger anywhere', and finally 'burying homeland in heart'. Conclusion: The research findings not only suggest crucial materials for training prospective nurses overseas for their successful settlement, but also shed lights on related problems and solutions with ageing experience in overseas employment.

• The Korean Journal of Community Living Science
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• v.24 no.1
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• pp.37-49
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• 2013

The purpose of this study is to explore how health and health behavior factors moderate the relation between socio-economic position(SEP) and Korean elderly people's self-rated health status. The data sources are from the Korean Longitudinal Study of Aging(2008). The analysis sample consists of 4,040 cases. Analysis of the results shows that health characteristics such as ADL, MMSE, geriatric depression, and pain are significant predictors of self-rated health status. In addition, exercise and drinking alcohol also prove to be factors influencing self-rated health status. Health factor such as MMSE and health behavior factors such as drinking alcohol served as moderators of the influences of SEP on one's self-rated health status. For example, higher MMSE provides a slight increase to the positive relationship between SEP and self-rated health status. In addition, those who responded yes to drinking alcohol, compared to those who responded no, provides an increase to the positive relationship between SEP and one's self-rated health status.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.28 no.3
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• pp.48-65
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• 2015

Objectives : The aim of this study is to analyze recent clinical research of the acupuncture for the treatment of tinnitus.Methods : We searched pubmed for foreign journals with the title/abstract 'tinnitus, acupuncture' published in the last 10 years, and for domestic journals we searched NDSL, RISS, KISS, The National Assembly Library, The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology with the same conditions as foreign journals.Results : We selected total 10 papers: 7 RCTs, 1 RCT protocol, 1 clinical trial, 1 Systematic Review. In RCT, all studies showed positive effect, however in comparison with the control groups, only 2 studies showed meaningful effects.Conclusions : Positive effect of the acupuncture on tinnitus is expected, but because of several limits observed in many papers, we can't draw defined conclusions. Further well-designed researches are needed.

• The Journal of Internal Korean Medicine
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• v.39 no.3
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• pp.389-404
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• 2018

Objective: The aim of this study was to investigate acupuncture therapy for post-stroke cognitive disorder to suggest the methods of a study about acupuncture therapy. Methods: Several academic databases were used in this study, including National Digital Science Library (NDSL), National Assembly Library of Korea, Korean Traditional Knowledge Portal, Research Information Sharing Service (RISS), Korean studies Information Service System (KISS), Korean Medical Database (KMBASE), Korea Med, Oriental Medicine Advanced Searching Integrated System (OASIS), PubMed, MEDLINE with Full Text, and China National Knowledge Infrastructure (CNKI). Keywords used were "중풍", "뇌졸중", "인지장애", "침", "acupuncture", and "cognitive disorder". Results: Ultimately, 28 papers were investigated. that were mainly published in 2012 and 2016. Of these, More than two-thirds received a score of one or less on the Jadad scale. Acupuncture points such as GV20, GV24, PC6, EX-HN1, SP6, and GV26 were most frequently used. The treatment duration was mostly 30 minutes or less, and the treatment cycle was mostly for four weeks. Dilatational wave was generally used in pulse wave form, and amplitude of electricity was increased until patients were able to endure. G6805 was generally used in electric acupuncture apparatus. According to results of acupuncture treatment, assessments such as the MMSE (Mini Mental State Examination) and the Montreal Cognitive Function Assessment Scale (MoCA) showed statistically significant improvements in 28 studies. Conclusions: Future research is needed to standardize the treatment of acupuncture, and more diversified high quality papers should be published to help clarify the therapeutic effects of acupuncture and the mechanisms of cognitive disorder post-stroke.

• Food Science of Animal Resources
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• v.33 no.6
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• pp.715-722
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• 2013

Heugu (Korea Black Cattle) is one of the indigenous cattle breeds in Korea; however there has been severe lack of genomic studies on the breed. In this study, we report the first whole genome resequencing of Heugu at higher sequence coverage using Illumina HiSeq 2000 platform. More than 153.6 Giga base pairs sequence was obtained, of which 97% of the reads were mapped to the bovine reference sequence assembly (UMD 3.1). The number of non-redundantly mapped sequence reads corresponds to approximately 28.9-fold coverage across the genome. From these data, we identified a total of over six million single nucleotide polymorphisms (SNPs), of which 29.4% were found to be novel using the single nucleotide polymorphism database build 137. Extensive annotation was performed on all the detected SNPs, showing that most of SNPs were located in intergenic regions (70.7%), which is well corresponded with previous studies. Of the total SNPs, we identified substantial numbers of non-synonymous SNPs (13,979) in 5,999 genes, which could potentially affect meat quality traits in cattle. These results provide genome-wide SNPs that can serve as useful genetic tools and as candidates in searches for phenotype-altering DNA difference implicated with meat quality traits in cattle. The importance of this study can be further pronounced with the first whole genome sequencing of the valuable local genetic resource to be used in further genomic comparison studies with diverse cattle breeds.