• 한국미생물·생명공학회지
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• 제49권1호
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• pp.1-8
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• 2021

Human breast milk is a potential source of bacteria for the development of the intestinal microbiota of infants. Several species within the genera Lactobacillus and Bifidobacterium were demonstrated to shape the gut microbiota of infants. In this study, the bacterial diversity was investigated in the breast milk and feces of a mother-infant pair, and probiotic candidates were identified. Importantly, the novel L. gasseri EJL and B. breve JTL strains were isolated from breast milk and infant feces samples, respectively; their completed genome was resolved using de novo sequencing. In addition, the bacterial composition in the infant's feces at 1 week revealed the prevalence of Bifidobacterium and Streptococcus; a higher diversity was observed after 3 weeks. In particular, the abundance of Akkermansia was sharply increased at 7 weeks, further increasing thereafter, up to 15 weeks. Our results suggest that human breast milk and infant's feces are a source of probiotic candidates.

• 대한의용생체공학회:의공학회지
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• 제27권1호
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• pp.30-37
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• 2006

Injecting currents into an electrically conducting subject, we may measure the induced magnetic flux density distributions using an MRI scanner. The measured data are utilized to reconstruct cross-sectional images of internal conductivity and current density distributions in Magnetic Resonance Electrical Impedance Tomography (MREIT). Injection currents are usually provided in a form of mono-polar or bi-polar pulses synchronized with an MR pulse sequence. Given an MRI scanner performing the MR phase imaging to extract the induced magnetic flux density data, the current source becomes one of the key parts determining the signal-to-noise ratio (SNR) of the measured data. Since this SNR is crucial in determining the quality of reconstructed MREIT images, special care must be given in the design and implementation of the current source. This paper describes a current source design for MREIT with features including interleaved current injection, arbitrary current waveform, electrode switching to discharge any stored charge from previous current injections, optical isolation from an MR spectrometer and PC, precise current injection timing control synchronized with any MR pulse sequence, and versatile PC control program. The performance of the current source was verified using a 3T MRI scanner and saline phantoms.

• 센서학회지
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• 제15권5호
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• pp.341-346
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• 2006

We have fabricated SOI CMOS active pixel image sensor with the pinned photodiode on handle wafer in order to reduce dark currents and improve spectral response. The structure of the active pixel image sensor is 4 transistors APS which consists of a reset and source follower transistor on seed wafer, and is comprised of the photodiode, transfer gate, and floating diffusion on handle wafer. The source of dark current caused by the interface traps located on the surface of a photodiode is able to be eliminated, as we apply the pinned photodiode. The source of dark currents between shallow trench isolation and the depletion region of a photodiode can be also eliminated by the planner process of the hybrid bulk/SOI structure. The photodiode could be optimized for better spectral response because the process of a photodiode on handle wafer is independent of that of transistors on seed wafer. The dark current was about 6 pA at 3.3 V of floating diffusion voltage in the case of transfer gate TX = 0 V and TX=3.3 V, respectively. The spectral response of the pinned photodiode was observed flat in the wavelength range from green to red.

• 한국균학회지
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• 제19권1호
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• pp.41-46
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• 1991

화학공장폐수가 유입되는 곳의 자연수에서 프탈산화합물을 탄소원으로 이용하여 성장하는 효모 3종을 분리하였는데, 형태학적 및 생화학적 특성의 연구결과 이들은 Candide sp., Rhodotorula sp., To-rulopsis sp. 로 동정되었다. 분리한 효모들은 프탈산화합물 뿐만 아니라 톨류엔 등 다수의 방향족화합물을 이용하여 성장하기에 화학공업의 발달로 인하여, 자연생태에 다량 유입, 축적되고 있는 난분해성 방향족화합물의 효율적 생분해 방법을 모색하는에 활용될 수 있으리라 추정되며, 따라서 이들 효모에 대한 다각적 연구가 필요하다고 사료된다.

• 환경영향평가
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• 제22권4호
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• pp.381-387
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• 2013

In order to improve the environmental vibration, it is necessary to method for not only reduce the vibration source, but also control the vibration path. In this study, we used borebole for estimate the vibration reduction. And also, we analyzed displacement and vibration velocity caused by the position of borehole as well as the condition of borehole in ground structure. Visual FEA(Finite Element Analysis) program was used in this numerical analysis. The results are as follows : The displacement magnitude and X, Y direction displacement were represented to different results due to the condition and position of borehole, and were represented to the lowest values when the position of borehole is the most close condition from the vibration source. And also, the vibration velocity was decreased as using borebole in ground structure. The isolation efficiency of the vibration was calculated to maximum 18.40% when borehole was established to the most close position from the vibration source and the receive point.

• Journal of Microbiology and Biotechnology
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• 제21권11호
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• pp.1101-1108
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• 2011

The rise in global energy demand has prompted researches on developing strategies for transforming coal into a cleaner fuel. This requires isolation of microbes with the capability to degrade complex coal into simpler substrates to support methanogenesis in the coal beds. In this study, aerobic bacteria were isolated from an Indian coal bed that can solubilize and utilize coal as the sole source of carbon. The six bacterial isolates capable of growing on coal agar medium were identified on the basis of their 16S rRNA gene sequences, which clustered into two groups; Group I isolates belonged to the genus Rhizobium, whereas Group II isolates were identified as Chelatococcus species. Out of the 4 methods of whole genome fingerprinting (ERIC-PCR, REP-PCR, BOX-PCR, and RAPD), REP-PCR showed maximum differentiation among strains within each group. Only Chelatococcus strains showed the ability to solubilize and utilize coal as the sole source of carbon. On the basis of 16S rRNA gene sequence and the ability to utilize different carbon sources, the Chelatococcus strains showed maximum similarity to C. daeguensis. This is the first report showing occurrence of Rhizobium and Chelatococcus strains in an Indian coal bed, and the ability of Chelatococcus isolates to solubilize and utilize coal as a sole source of carbon for their growth.

• 보건교육건강증진학회지
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• 제18권2호
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• pp.141-156
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• 2001

This study was performed to identify the occupational diseases in the dental technicians working in Korea, and to elucidate the main related affecting factors for the occurrence of the occupational diseases. The research was carried out using a mail questionnaire and data collection was done for two months from April 15, 2000. The questionnaires were delivered to 1000 dental technicians working at 250 dental laboratories which were chosen among the total 1330 dental laboratories in south Korea. And 763 questionnaires were collected, then 739 questionnaires were used for a logistic and a multiple regression analyses. The results obtained in this study are summarized as follows: 1. The occupational diseases in the dental technicians included pneumoconiosis, chronic bronchitis, asthma, pneumonia, hyposmia, allergic dermatitis, eczema, contagious dermatitis, central nervous disorder, dysfunction of finger, vertebral disorder, dysfunction of interphalangeal joint, ophthalmitis, auditory dysfunction, otitismedia, optic trauma, and bum. 2. The main related affecting factors for the occurrence of the occupational diseases in the dental technicians were elucidated as follows: On the ccurrence of chronic bronchitis, vibration of equipment and job career were affected positively. On the ccurrence of asthma, job career and career on current working part were affected positively, but exhaust ventilation, work hour were affected negatively. On the occurrence of eczema, career on current working part and vibration of equipment were affected positively, but personal protective equipment, local exhaust ventilation, isolation of gas source were affected negatively. And eczema was occurred more in methyl methacrylate work than in any other work part. On the occurrence of finger dysfunction, vibration of equipment and noise of work place were affected positively. But personal protective equipment, local exhaust ventilation, isolation of dust and gas source were affected negatively. But finger dysfunction was occurred more in metal polishing than in any other work part. On the occurrence of auditory dysfunction, noise of work place were affected negatively. The results obtained in this study can give a valuable information for a prevention of the occupational diseases in the dental technicians working in Korea, and for keeping them in healthy. This study also can be helpful for a researcher who is aiming at a identification of occupational diseases and a elucidation of related affecting factors in a similar occupation.

• 한국토양비료학회지
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• 제34권6호
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• pp.394-400
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• 2001

가축분 및 음식물 퇴비 132점에서 517균주를 분리하고 CMC와 xylan 및 PGA 배지에서 강한 활성을 가지는 10여개의 균주를 선별하여 배추종자 발아를 이용한 작물 inhibition test와 오이 육묘실험으로 growth test를 거쳐 생육이 가장 양호한 LYH201 균주를 야생균주로 선발하였다. Bergey's manual 방법으로 특성을 조사한 결과 LYH201균주는 Gram 양성균으로 내생포자 형성, oxidase, CMCCase, xylanase, catalase, V-P test, methyl red test, arabinose 등의 탄소원 이용성은 양성이었으며, indole을 생성하고, urease, lecithinase, dihydrolase test는 음성이었고, 전자현미경으로 관찰한 결과 길이가 $2.5{\sim}3.0{\mu}m$, 너비가 $0.5{\sim}0.7{\mu}m$의 간균인 Bacillus subtilis로 확인되었다. Bacillus subtilis LYH201 균주를 MMY를 이용하여 배양한 결과 온도 $50^{\circ}C$, pH 6.0에서 생육이 가장 좋았다.

• 한국수산과학회지
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• 제44권4호
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• pp.325-331
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• 2011

Nonylphenol (NP), which is well known as an endocrine disrupter, has been detected widely in untreated sewage or waste water streams. Given the necessity of discovering an eco-friendly method of degrading this toxic organic compound, this study was conducted to isolate NP-degrading microorganisms from the aqueous environment. NP-degrading microbes were isolated through NP-containing enrichment culture. Finally, a microbial consortium, SW-3, capable of degrading NP with high efficiency, was selected from the mixture sample. The microbial consortium SW-3 was able to degrade over 99% of 100 ppm NP in the culture medium for 40 days at $25^{\circ}C$. The microbial consortium SW-3 seemed to utilize NP as a carbon source, since NP was the sole carbon source in the culture medium. In order to isolate the NP-degrading bacterium, we further conducted single colony isolation using the microbial consortium SW-3. Four strains isolated from SW-3 exhibited lower NP-degradation efficiency than that of SW-3, suggesting that NP was degraded by the co-metabolism of the microbial consortium. We suggest that the microbial consortium obtained in this study would be useful in developing an eco-friendly bioremediation technology for NP degradation.

• KSBB Journal
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• 제19권3호
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• pp.200-205
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• 2004

반월공단의 염색폐수와 염료폐수를 균원시료로 하여 반응성 염료의 색도제거능이 나타난 13종의 균주를 분리하고, 산소농도에 따른 영향을 살펴보기 위하여 교반에 따른 색도제거율을 살펴 본 결과, 교반을 진행하지 않은 경우 효율이 더 높은 효율을 얻을 수 있었다. 또한, 5가지 반응성 염료 (reactive blue 19, reactive blue 21, reactive red 180, reactive red 195, reactive yellow 145)를 가지고 색도제거 실험을 진행한 결과 2종의 균주가 높은 효율을 보였다. 이 2종의 균주를 동정한 결과 Bacillus anthracis와 Bacillus cereus로 판명되었다. 최적 조건을 살펴보기 위하여 온도와 초기 pH 영향에 따른 색도 제거율을 알아보기 위하여 실험을 진행한 결과 35$^{\circ}C$, pH 7에서 높은 색도제거율을 보였다. 또한 탄소원과 질소원에 따른 영향을 살펴보기 위하여 Bacillus anthracis로 실험한 결과 glucose, yeast extract를 사용한 경우 89%의 높은 색도 제거율을 얻을 수 있었다. 이러한 결과로 미루어 볼 때 분리된 두 균주는 염색폐수의 색도제거에 효과적인 균주라고 사료된다.