• 대한청각학회지
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• 제24권3호
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• pp.119-126
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• 2020

Background and Objectives: In distracting listening conditions, individuals need to pay extra attention to selectively listen to the target sounds. To investigate the amount of listening effort required in reverberating and noisy backgrounds, a semantic mismatch was examined. Subjects and Methods: Electroencephalography was performed in 18 voluntary healthy participants using a 64-channel system to obtain N400 latencies. They were asked to listen to sounds and see letters in 2 reverberated×2 noisy paradigms (i.e., Q-0 ms, Q-2000 ms, 3 dB-0 ms, and 3 dB-2000 ms). With auditory-visual pairings, the participants were required to answer whether the auditory primes and letter targets did or did not match. Results: Q-0 ms revealed the shortest N400 latency, whereas the latency was significantly increased at 3 dB-2000 ms. Further, Q-2000 ms showed approximately a 47 ms delayed latency compared to 3 dB-0 ms. Interestingly, the presence of reverberation significantly increased N400 latencies. Under the distracting conditions, both noise and reverberation involved stronger frontal activation. Conclusions: The current distracting listening conditions could interrupt the semantic mismatch processing in the brain. The presence of reverberation, specifically a 2000 ms delay, necessitates additional mental effort, as evidenced in the delayed N400 latency and the involvement of the frontal sources in this study.

• Journal of Audiology & Otology
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• 제24권3호
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• pp.119-126
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• 2020

Background and Objectives: In distracting listening conditions, individuals need to pay extra attention to selectively listen to the target sounds. To investigate the amount of listening effort required in reverberating and noisy backgrounds, a semantic mismatch was examined. Subjects and Methods: Electroencephalography was performed in 18 voluntary healthy participants using a 64-channel system to obtain N400 latencies. They were asked to listen to sounds and see letters in 2 reverberated×2 noisy paradigms (i.e., Q-0 ms, Q-2000 ms, 3 dB-0 ms, and 3 dB-2000 ms). With auditory-visual pairings, the participants were required to answer whether the auditory primes and letter targets did or did not match. Results: Q-0 ms revealed the shortest N400 latency, whereas the latency was significantly increased at 3 dB-2000 ms. Further, Q-2000 ms showed approximately a 47 ms delayed latency compared to 3 dB-0 ms. Interestingly, the presence of reverberation significantly increased N400 latencies. Under the distracting conditions, both noise and reverberation involved stronger frontal activation. Conclusions: The current distracting listening conditions could interrupt the semantic mismatch processing in the brain. The presence of reverberation, specifically a 2000 ms delay, necessitates additional mental effort, as evidenced in the delayed N400 latency and the involvement of the frontal sources in this study.

• International Journal of Industrial Entomology and Biomaterials
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• 제11권2호
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• pp.81-86
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• 2005

The mode of transmission, effect on fecundity, hatching and tissues specificity of a microsporidian $(Lb_{ms})$ recovered from Lamerin breed of the silkworm Bombyx mori L. was studied and compared with standard strain Nosema bombycis. Peroral inoculation of $Lb_{ms}$ or N. bombycis to zeroday of $4^{th}$ instar larvae of silkworm was the most suitable method for producing information on development of stage specific mortality, pupation and obtaining infected adults for transovarial transmission studies. It was observed that pupal mortality, the percentage of moths emerged and the percentage of moths infected were significantly high in N. bombycis infected batches as compared $(Lb_{ms})$ in all the three tested breeds of the silkworm. However no significant difference was observed in larval mortality. The fecundity and hatchability was not affected significantly in $(Lb_{ms})$ infected adults, however significant reduction in egg production, fecundity, hatchability and increased egg retention was observed in mother moths infected with N. bombycis. The $(Lb_{ms})$ is transmitted both horizontally and vertically at lower rate due to its low rate of proliferation. The trans ovarial transmission of $(Lb_{ms})$ to the $F_1$ progeny generation through eggs averaged only $61.33\pm5.10\%$ whereas N. bombycis was transmitted at $100\%$. The $(Lb_{ms})$ had low oral infectivity and low transovarial transmission in silkworm B. mori.

• KSBB Journal
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• 제22권4호
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• pp.234-238
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• 2007

본 연구에서는 전극분무 이온화-이온 포획 질량 분석기를 이용하여 인체 IgG의 N-연결 글라이칸 중 이중촉각 구조를 가지면서 비환원 말단의 갈락토오즈 개수가 0, 1, 2 개인 서로 다른 세 가지 글라이칸의 단일 쪼개짐 (MS/MS) 및 다중 쪼개짐 현상을 관찰하고 이를 구조 분석에 이용하였다. MS/MS 분석에서는 퓨코오즈가 결합된 환원 말단의 N-아세틸 글루코사민의 0,2-고리 쪼개짐으로 파생되는 조각 피크가 가장 높은 세기로 나타나는 것을 관찰할 수 있었고, 전구체 피크와 별개로 연속적인 당 단위체의 쪼개짐이 일어나는 것을 알 수 있었다. 또한 G1 글라이칸의 경우에서만 비환원 말단의 갈락토오즈와 N-아세틸글루코사민이 결합된 채 쪼개지는 현상이 일어나는 것을 관찰할 수 있었다. 다중 쪼개짐 질량 분석 기법을 이용하여 MS/MS 스펙트럼에서 나타나는 조각 피크들의 구조를 재확인할 수 있었고, 이를 트리 구조로 정리할 수 있었다. 또한 추가적인 2,4-고리 쪼개짐 현상이 환원 말단 하나 바깥쪽의 N-아세틸 글루코사민에서 공통적으로 일어나는 것을 관찰할 수 있었다. 이와 같은 다중 쪼개짐 질량 분석기법을 이용하여 보다 복잡한 구조의 글라이칸 구조 분석에 이용될 수 있을 것으로 기대된다.

• Archives of Pharmacal Research
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• 제4권2호
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• pp.85-90
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• 1981

A quantitative GC-MS spectrometric assay was used for the determination of residual N, N-dimethylaniline as a contaminant in commercial penicillin derivatives from various sources. The assay utilizes selective ion focusing to monitor in a GC effluent the molecular ions of DMA generated by electron impact ionization. This method includes dissolution of the sample in alkaline solution, extraction of organic base with cyclohexane and injection into GC-MS with a 3% OV-17 column. Levels of 50 ppb of DMA were easily measured with a coeffecient of varation less than 5 % and recoveries from spiked samples exceeded 97 %. The results of the determinations of DMA in various commercial penicillins were relatively free of this contaminant.

• 한국지능시스템학회논문지
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• 제24권4호
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• pp.430-436
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• 2014

행렬스타 그래프와 하프팬케익 그래프는 스타 그래프의 변형으로 노드 대칭성과 허용도 등 여러 가지 좋은 성질을 갖는다. 본 연구에서는 행렬스타 그래프와 하프팬케익 그래프 사이의 임베딩을 분석한다. 연구 결과로 행렬스타 그래프 $MS_{2,n}$는 하프팬케익 그래프 $HP_{2n}$에 연장율 5, 확장율 1에 임베딩 가능하다. 또한 하프팬케익 그래프 $HP_{2n}$는 행렬스타 그래프 $MS_{2,n}$에 임베딩하는 연장율 비용이 O(n)임을 보인다. 이러한 결과는 스타 그래프에서 개발된 여러 가지 알고리즘을 하프팬케익 그래프에서 상수의 추가적인 비용으로 시뮬레이션 할 수 있음을 의미한다. 왜냐하면 스타 그래프 $S_n$은 행렬스타 그래프 $MS_{2,n}$의 부분 그래프이기 때문이다.

• 분석과학
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• 제21권5호
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• pp.403-411
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• 2008

방사성 액체폐기물의 용매추출 공정에서 발생되는 방사선 분해현상을 연구하기 위하여 추출제로 사용되는 dimethyldibutyltetradecylmalonamide (DMDBTDMA)를 합성하고, 합성된 DMDBTDMA를 $^{60}Co$ 감마 방사선으로 조사시킬 때 생성되는 방사선 분해산물을 정량 분석하였다. 방사선 조사된 DMDBTDMA에 대한 FT-IR 스펙트럼과 EI-질량스텍트럼 및 GC/MS-SIM 방법으로 측정한 결과를 바탕으로 n-methylbutylamine, tetradecane, 1-tetradecanol 3종의 방사선 분해산물의 존재를 확인하였다. 3종의 방사선 분해산물 농도는 이들 표준물질과 n-dodecane을 내부표준물질(ISTD)로 사용하여 GC/MS-SIM 방법으로 정량 분석하였다. 방사선 분해산물에 대한 총 이온 크로마토그램에서 나타난 머무름 거동, 분리도와 해상도 측면에서 만족스런 결과를 얻었으며, 총 이온 크로마토그램에서 n-methylbutylamine, n-dodecane, tetradecane 및 1-tetradecanol 각각의 성분에 대한 피크 검출시간은 각각 2.35분, 8.83분, 10.68분 및 12.75분 이었다. 그리고 tetradecane은 방사선 분해산물의 농도가 DMDBTDMA의 방사선 흡수선량과 비례하는 상관관계를 확인하였다.

• 한국식품위생안전성학회지
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• 제14권2호
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• pp.140-145
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• 1999

Analytical method for preservatives in food was developed using gas chromatography/mass spectrometry (GC/MS). Propionic acid, sorbic acid, benzoic acid, ethyl salicylate, ethyl p-hydroxy benzoate, iso-propyl p-hydroxy benzoate, n-propyl p-hydroxy benzoate, iso-butyl p-hydroxy benzoate, n-butyl p-hydroxy benzoate, p-hydroxy benzoic acid and dehydro acetic acid were extracted from cooling beverage with diethyl ether. The polar hydroxyl and carboxyl groups of food preservatives were derivatized with N-methyl-N-tert-butyldimethylisilyl-trifluoroscetamide (MTBSTFA) to form the corresponding tert-bytyldimethyl-silylated derivatives, and submitted to GC/MS analysis. The mass spectra of the derivatives were investigated for the selection of monitoring ions for multi-residue analysis of 11 preservatives by GC/MS. The macro program was also developed for the qualitative analysis of these preservatives in food.

• 대한환경공학회지
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• 제32권6호
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• pp.639-648
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• 2010

본 연구는 극미량의 BPA 분석법을 정립하기 위하여 HPLC-MS/MS를 이용한 BPA 분석 조건을 개발하였고, 초음파를 이용한 BPA의 분해 특성을 조사하였다. HPLC-MS/MS에 의한 BPA의 MDL과 LOQ는 각각 0.13 nM과 1.3 nM로 조사되었는데, 이는 기존의 HPLC-UV (MDL: 81.1 nM, LOQ: 811 nM) 및 FLD (MDL: 4.6 nM, LOQ: 46 nM) 보다 약 620배 및 35배 우수하였으며, U.S. EPA의 음용수 권고기준(1.53 ${\mu}M$ 혹은 350 ${\mu}g/{\ell}$)의 약 1,180배 이하까지 정량분석이 가능하였다. 초음파 조사에 따른 BPA의 분해효율은 저주파(28 kHz)를 제외한 중?고주파 조건(580 and 1000 kHz)에서 반응 30분 이내에 95%이상 제거되었다. 특히 BPA의 분해효율 및 k1의 결과는 580 kHz에서 가장 우수하였는데, 이는 580 kHz 근처의 주파수 영역에서 최적의 초음파 공동현상 및 열분해/산화분해가 일어남을 알 수 있었다. 0.01 mM의 $CCl_4$를 첨가하여 분해효율을 측정한 결과 30분 이내에 BPA 초기농도(1 ${\mu}M$)의 98% 이상까지 제거되었으며, 반응 초기(5분)와 후기(30분)의 $k_1$값은 무첨가 반응에 비해 각각 1.4배 및 1.1배씩 증가하였다. 10 mM의 t-BuOH이 첨가된 결과 무첨가 반응에 비해 약 60% 이상 BPA 분해효율이 감소한 것을 감안할 때 BPA의 주된 초음파 기전은 OH 라디칼에 의한 산화분해임을 알 수 있었다. 그러나 t-BuOH이 첨가된 반응시간 동안(30분) 약 33%의 BPA가 분해가 일어난 것은 OH 라디칼 뿐 아니라 열분해 및 기타 라디칼 등에 의한 분해가 진행되었을 것으로 판단된다.

• Mass Spectrometry Letters
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• 제12권3호
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• pp.66-75
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• 2021

Interleukin-4 (IL-4) and IL-13 are cytokines secreted by immune cells. Cytokines induce the proliferation of macrophages or promote the differentiation of secretory cells. The initiation and progression of allergic inflammatory diseases, such as asthma, are dependent on cytokines acting through related receptor complexes. IL-4 and IL-13 are N-glycoproteins. Glycan structures in glycoproteins play important roles in protein folding, protein stability, enzymatic function, inflammation, and cancer development. Therefore, the glycan structure of IL-4 and IL-13 needs to be elucidated in detail for the development of effective therapies. We report the first attempt to characterize the site-specific N-glycosylation of recombinant IL-4 and IL-13 via liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. The tandem mass spectra of intact N-glycopeptides were identified using the Integrated GlycoProteome Analyzer (I-GPA) platform, which can automatically and rapidly analyze multiple N-glycopeptides, including their glycan composition and amino acid sequences. The recombinant IL-4 and IL-13 were identified with amino acid sequence coverages of 84% and 96%, respectively. For IL-4, 52 glycoforms on one N-glycosylation site were identified and quantified. In IL-13, 232 N-glycopeptides from three N-glycosylation sites were characterized, with the site Asn52 being the most extensively glycosylated (~80%). The complex glycans were the most abundant glycan on IL-4 and IL-13 (~96% and 91%, respectively), and the biantennary glycans were the most abundant in both recombinant IL-4 and IL-13 proteins.