• 미생물학회지
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• 제14권1호
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• pp.39-47
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• 1976

This experiment was designed to study the effects of temperature on the peroxidase isoenzymes of a mesophilic microorganism, Escherichia coli (grown within biokinetic zone). Optimum temperature for the growth of E. coli was $37{\circ}C.$ Three different temperatures, 20, 30 and $40{\circ}C,$ were selected. And the isoenzyme patterns of peroxidase of E. coli, growth respectively at each temperature, were analysed by disc electrophoresis. The sample of 20.deg.C showed 4 bands, that of 30.deg.C, 5 bands and that of 40.deg.C, 6 bands. Two dark bands (higher molecular weight, 56,000 and 54,000) and two light bands (lower molecular weight, 11,500 and 10,000) were constant at all samples. But two intermediate bands (M.W.44,000 and 34,000) were variable ; at $20{\circ}C,$ no banding pattern, one band 9M.W. 34,000) only at $30{\circ}C,$ and at $40{\circ}C$ two bands were appeared. And the shifts of growth temperatures between 30.deg.C and 40.deg.C showed the alteration of the isoenzyme patterns ; the isoenzyme patterns of the smaple of tmeperature shift from $30{\circ}C$ to $40{\circ}C$ were same as that of 40.deg.C and vice versa.

• Bulletin of the Korean Chemical Society
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• 제20권12호
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• pp.1428-1432
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• 1999

[Fe$^{II}$(BLPA)DBCH]BPh₄ (1), a new functional model for the extradiol-cleaving catechol dioxygenases, has been synthesized, where BLPA is bis(6-methyl-2-pyridylmethyl)(2-pyridylmethyl)amine and DBCH is 3,5-di-tert-butylcatecholate monoanion. ¹H NMR and EPR studies confirm that 1 has a high-spin Fe(II) (S = 2) center. The electronic spectrum of 1 exhibits one absorption band at 386 nm, showing the yellow color of the typical [Fe$^{II}$(BLPA)] complex. Upon exposure to O₂, 1 is converted to an intense blue species within a minute. This blue species exhibits two intense bands at 586 and 960 nm and EPR signals at g = 5.5 and 8.0 corresponding to the high-spin Fe(III) complex (S = 5/2, E/D = 0.11). This blue complex further reacts with O₂ to be converted to (μ-oxo)Fe$^{III}_2$ complex within a few hours. Interestingly, 1 affords intradiol cleavage (65%) and extradiol cleavage (20%) products after the oxygenation. It can be suggested that 1 undergoes two different oxygenation pathways. The one takes the substrate activation mechanism proposed for the intradiol cleavage products after the oxidation of the $Fe^II\;to\;Fe^{III}$. The other involves the direct attack of O₂ to $Fe^{II}$ center, forming the $Fe^{III}$-superoxo intermediate which can give rise to the extradiol cleavage products. 1 is the first functional Fe(II) complex for extradiol-cleaving dioxygenases giving extradiol cleavage products.

• Advances in nano research
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• 제7권1호
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• pp.13-24
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• 2019

Well-crystalline $SnO_2$ nanoparticles of 4-5 nm size with different In contents were synthesized by hydrothermal process at relatively low temperature and characterized by transmission electron microscopy (TEM), microRaman spectroscopy and photoluminescence (PL) spectroscopy. Indium incorporation in $SnO_2$ lattice is seen to cause a lattice expansion, increasing the average size of the nanoparticles. The fundamental phonon vibration modes of $SnO_2$ lattice suffer a broadening, and surface modes associated to particle size shift gradually with the increase of In content. Incorporation of In drastically enhances the PL emission of $SnO_2$ nanoparticles associated to deep electronic defect levels. Although In incorporation reduces the band gap energy of $SnO_2$ crystallites only marginally, it affects drastically their dye degradation behaviors under UV illumination. While the UV degradation of methylene blue (MB) by undoped $SnO_2$ nanoparticles occurs through the production of intermediate byproducts such as azure A, azure B, and azure C, direct mineralization of MB takes place for In-doped $SnO_2$ nanoparticles.

• 말소리와 음성과학
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• 제12권4호
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• pp.19-25
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• 2020

This study examined thirty-one Korean students' pronunciation of an English passage using a speech recognition application, Speechnotes, and two Canadian raters' evaluations of their speech according to the International English Language Testing System (IELTS) band criteria to assess the possibility of using the application as a teaching aid for pronunciation education. The results showed that the grand average percentage of correctly recognized words was 77.7%. From the moderate recognition rate, the pronunciation level of the participants was construed as intermediate and higher. The recognition rate varied depending on the composition of the content words and the function words in each given sentence. Frequency counts of unrecognized words by group level and word type revealed the typical pronunciation problems of the participants, including fricatives and nasals. The IELTS bands chosen by the two native raters for the rainbow passage had a moderately high correlation with each other. A moderate correlation was reported between the number of correctly recognized content words and the raters' bands, while an almost a negligible correlation was found between the function words and the raters' bands. From these results, the author concludes that the speech recognition application could constitute a partial aid for diagnosing each individual's or the group's pronunciation problems, but further studies are still needed to match human raters.

• 천문학회보
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• 제44권2호
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• pp.36.3-36.3
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• 2019

We present a multiwavelength study of an ultraluminous X-ray source (ULX) in NGC 5252, which is known as a candidate for an intermediate-mass black hole. The ULX, located 22 arcsec away from the center of NGC 5252, was first discovered with the Chandra X-Ray Observatory. In the optical spectra, the strong narrow emission lines are found at the position of the ULX. It reveals that the ULX is likely associated with NGC 5252. The VLBA data of the ULX yields that the black hole mass of the ULX is smaller than 106 solar mass, inferred from the black hole fundamental plane. From the near-infrared imaging data, we find that the stellar mass associated with the ULX is smaller than ~107.9 solar mass, implying that the ULX can be a remnant of a merging dwarf. We also find that K-band luminosity of the ULX is two orders of magnitude smaller than typical active galactic nuclei at a given [OIII] luminosity. It may suggest the ULX lacks the dusty torus possibly due to the disappearance of dusty material during the recoiling process.

• 천문학회보
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• 제45권1호
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• pp.63.2-63.2
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• 2020

FLASH is a blind neutral hydrogen (HI) absorption line survey, eventually targeting about 100,000 background radio continuum sources in the entire southern sky using the full 36-antenna of the Australian Square Kilometre Array Pathfinder (ASKAP). Our primary goal is to search for associated and intervening HI absorption lines in the intermediate redshift range 0.4 < z < 1.0. The survey aims to understand the evolution of HI gas in galaxies as well as various physical mechanisms in active galactic nuclei, such as accretion and feedback processes. In this poster, we give an overview of the FLASH survey and present the preliminary results from our first 100-hrs of pilot observations. The latest survey data covers 1,000 square degrees and is ideal for validating observation and data processing in the continuous 300MHz-width low frequency ASKAP band (700-1000MHz). One of the crucial objectives of the pilot survey is to establish the analysis methodology that will be applied to upcoming large absorption surveys in the future. We discuss our data quality validation and present some detections of associated/intervening HI absorption lines. These absorption lines allow us to trace the cold gas properties of active and normal galaxies at higher redshifts where the HI emission line is too weak to be detectable.

• 한국산학기술학회논문지
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• 제11권11호
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• pp.4234-4243
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• 2010

치매의 특성상 집중력 결핍, 불안, 긴장 등으로 운동지도 현장에서 치매 고령자에게 운동을 지도하는데 어려움이 따른다. 이에 운동시간을 배분하여 실시하는 방법인 간헐적 운동을 제시하고자 한다. 연속적 운동과 간헐적 운동이 기능적 체력, 인지기능 및 일상생활수행능력에 미치는 영향을 구명하여 이들을 위한 적절한 운동 처방의 자료로 활용하는데 있다. 대상자 선정은 B광역시 A치매전문요양원에 거주하고 있는 여성 고령자로 DSM-IV 기준에 따라 확정적 치매의 진단을 받은 자이다. 연속적 운동군 6명, 간헐적 운동군 5명으로 총 11명을 최종 대상자로 선정하였다. 손발운동, 한국무용과 밴드운동을 실시하였다. 주 3회, 총 12주간 실시하였다. Borg's scale을 이용하여 준비 및 정리운동은 RPE 7-9, 본 운동은 RPE 11-13의 수준으로 실시하였다. 연속적 운동군은 1일 1회 30분간, 간헐적 운동군은 1일 3회 10분씩 총 30분간 실시하였다. 모든 자료는 SPSS Ver. 18.0을 사용하여 평균값과 표준편차를 산출하고, two-way repeated ANOVA를 실시하였다. 통계적 유의수준은 .05로 설정하였다. 기능적 체력과 인지기능에서 시기간 유의한 차이가 있었다. 일상생활수행능력에서 시기에서 차이가 없었다. 모든 항목에서 집단, 시기${\times}$집단은 유의한 차이가 없었다. 연속적 운동군과 간헐적 운동군의 효과가 유사하게 나타났다. 이는 모든 치매환자에게 일반화시키기에는 제한이 있지만 운동시간 배분에 있어 연속적 운동방법과 유사하게 간헐적 운동의 방법도 경증치매환자의 운동처방에 유효한 자료가 될 것으로 본다.

• Investigative Magnetic Resonance Imaging
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• 제21권3호
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• pp.162-170
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• 2017

Purpose: To evaluate the imaging findings of desmoid tumors using various imaging modalities and to evaluate whether diffusion-weighted imaging (DWI) can help differentiate between desmoid and malignant tumors. Materials and Methods: The study included 27 patients with pathologically confirmed desmoid tumors. Two radiologists reviewed 23 computed tomography (CT), 12 magnetic resonance imaging (MRI) and 8 positron emission tomography-computed tomography (PET-CT) scans of desmoid tumors and recorded data regarding the shape, multiplicity, size, location, degree of enhancement, and presence or absence of calcification or hemorrhage. The signal intensity of masses on T1- and T2-weighted imaging and the presence or absence of whirling or band-like low signal intensity on T2-weighted imaging were recorded. The apparent diffusion coefficient (ADC) values of the desmoid tumors in nine patients with DWIs were compared with the ADC values of 32 malignant tumors. The maximum standardized uptake value ($SUV_{max}$) on PET-CT images was measured in 8 patients who underwent a PET-CT. Results: The mean size of the 27 tumors was 6.77 cm (range, 2.5-26 cm) and four tumors exhibited multiplicity. The desmoid tumors were classified by shape as either mass forming (n = 18), infiltrative (n = 4), or combined (n = 5). The location of the tumors was either intra-abdominal (n = 15), within the abdominal wall (n = 8) or extra-abdominal (n = 4). Among the 27 tumors, 21 showed moderate to marked enhancement and 22 showed homogeneous enhancement. Two tumors showed calcifications and one displayed hemorrhage. Eleven of the 12 MR T2-weighted images showed whirling or band-like low signal intensity areas in the mass. The mean ADC value of the desmoid tumors ($1493{\times}10^{-6}mm^2/s$) was significantly higher than the mean of the malignant soft tissue tumors ($873{\times}10^{-6}mm^2/s$, P < 0.001). On the PET-CT images, all tumors exhibited an intermediate $SUV_{max}$ (mean, 3.7; range, 2.3-4.5). Conclusion: Desmoids tumors showed homogenous, moderate to marked enhancement on CT and MRI scans and a characteristic whirling or band-like pattern on T2-weighted images. DWI can be useful for the differentiation of desmoid tumors from malignant soft tissue tumors.

• 한국전자파학회논문지
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• 제21권4호
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• pp.352-361
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• 2010

본 논문에서는 C-대역 위성 통신용 20 W급 주파수 상향 변환기(BUC: Block Up Converter)를 소형화하기 위한 설계 방안을 제안하고, 이에 따른 제작 및 측정 결과를 제시하였다. 개발된 주파수 상향 변환기는 모뎀의 신호를 입력받아 적절한 주파수 필터링과 신호 세기 조절 및 전력 증폭 기능을 수행하며, 중간 주파수 회로, 국부 발진기 및 주파수 혼합기, 구동 증폭기, 전력 증폭기, 도파관 회로 및 전원 모듈의 6개 블럭으로 구성된다. 본 논문에서는 BUC를 소형화하기 위하여 개별 블럭을 각각 제작하여 케이블 등으로 연결하는 대신, 하나의 하우징 내에서 집적화하여 제작함으로써, $21{\times}14{\times}11cm^3$의 크기만을 가지도록 하였다. 특히 가장 큰 면적을 차지하는 도파관 필터 및 마이크로스트립-도파관 변환기를 하우징에 직접 제작하여 크기를 축소시켰다. 또한 Elliptic 필터를 포함한 다양한 마이크로스트립 필터를 설계하여 스퓨리어스 및 하모닉 규격을 만족시켰다. 제작된 주파수 상향 변환기는 43.7 dBm의 출력, 65 dB 이상의 이득, ${\pm}1.84$의 이득 평탄도, -35.7 dBc의 IMD3, -105 dBc의 하모닉 값을 가지는 우수한 특성을 나타내었다.

• Tuberculosis and Respiratory Diseases
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• 제83권4호
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• pp.289-294
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• 2020

Background: Line probe assay (LPA) is standard diagnostic tool to detect multidrug resistant tuberculosis. Non-interpretable (NI) results in LPA (complete missing or light wild-type 3 and 8 bands with no mutation band in rpoB gene region) poses a diagnostic challenge. Methods: Sputum samples obtained between October 2016 and July 2017 at the Intermediate Reference Laboratory, All India Institute of Medical Sciences Hospital, New Delhi, India were screened. Smear-positive and smear-negative culture-positive specimens were subjected to LPA Genotype MTBDRplus Ver 2.0. Smear-negative with culture-negative and culture contamination were excluded. LPA NI samples were subjected to phenotypic drug susceptibility testing (pDST) using MGIT-960 and sequencing. Results: A total of 1,614 sputum specimens were screened and 1,340 were included for the study (smear-positive [n=1,188] and smear-negative culture-positive [n=152]). LPA demonstrated 1,306 (97.5%) valid results with TUB (Mycobacterium tuberculosis) band, 24 (1.8%) NI, three (0.2%) valid results without TUB band, and seven (0.5%) invalid results. Among the NI results, 22 isolates (91.7%) were found to be rifampicin (RIF) resistant and two (8.3%) were RIF sensitive in the pDST. Sequencing revealed that rpoB mutations were noted in all 22 cases with RIF resistance, whereas the remaining two cases had wild-type strains. Of the 22 cases with rpoB mutations, the most frequent mutation was S531W (n=10, 45.5%), followed by S531F (n=6, 27.2%), L530P (n=2, 9.1%), A532V (n=2, 9.1%), and L533P (n=2, 9.1%). Conclusion: The present study showed that the results of the Genotype MTBDRplus assay were NI in a small proportion of isolates. pDST and rpoB sequencing were useful in elucidating the cause and clinical meaning of the NI results.