• 생명과학회지
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• 제8권6호
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• pp.654-659
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• 1998

NR2B는 연접후 치밀질의 주요 tyrosine 인산화 단백질이다. 본 연구에서는 mass spectrometry 방법을 적용하여 NR2B의 tyrosine 인산화 위치를 동정하였다. NR2B를 N-octyl glucoside (NOG)에 용해되지 않는 PSD 분획으로부터 SDS-PAGE와 electroelution방법으로 분리하였다. 분리한 단백질을 NR2B와 phos-photyrosine에 특이한 항체로 조사한 결과 이들은 phosphotyrosine을 유지하고 있는 NR2B임이 확인되었다. 이 단백질을 trypsin 혹은 endolys-C 처리하고, matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry 방법으로 조사한 결과 Tyr-1304이 인산화됨을 확인하였다.

• 한국광물학회지
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• 제18권2호
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• pp.127-134
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• 2005

금속제련공학 및 환경과학 분야에 있어서 물질전체를 구성하고 있는 화학적 조성이 중요한 요소이나, 입자 표면의 화학조성과 미분화된 입자들의 표면 반응성을 제어함과 동시에, 입자 계면에서 일어나는 중금속과 유기물질등의 반응은 제련공정과 환경오염에 중요한 역할을 한다. 그러므로, 수용액상에 존재하는 여러 종류의 화학 물질과 광물입자 표면 사이에서 일어나는 계면반응 과정의 이해는 상당히 중요한 것이다. 일반적으로 입자 표면 분석에는 ex-situ 법을 사용하는 X-ray photo-electron spectroscopy (XPS) 분석 방법이 많이 적용되고 있으나, 이는 분석대상시료의 크기가 보통 100 마이크론에서 1 cm 정도의 범위 안에 혼재-혼합되어있는 고체 입자들을 분석하기 때문에 채취 분석된 X-ray의 원래 발산한 입자표면을 분석할 수는 없다. 그래서 본 연구에서는 Time-of-Flight Secondary-Ion Mass Spectroscopy (TOF-SIMS)를 응용하여 황화광물의 부유선광 공정 중 생성된 미세한 유화광물입자$(30\~75\;microns)$ 표면에 형성된 무기, 유기물의 반응 관찰을 통해 이들의 정성분석 및 상대적 정량분석법을 연구하고자 하였다.

• 대한임상검사과학회지
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• 제52권3호
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• pp.221-228
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• 2020

Ochrobactrum anthropi는 oxidase를 생산하는 비발효산소성 그람음성 막대균으로 외관이 비슷하고 oxidase가 양성인 비발효 세균과 혼합배양 시 구분이 힘들고 생화학적 동정 장비로는 정확한 동정에 한계가 있다. 따라서 본 연구에서는 생화학적 검사 방법으로 동정이 힘든 세균동정의 Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry Platform (MALDI-TOF) 법의 유용성을 제시하고자 하였다. MicroScan을 이용해 검사했던 O. anthropi 5례를 분석한 결과, 최종보고까지 6.2일이 소요되었으며 E. coli의 3.0일에 비해 3.5일이 더 소요되었다. 5번 환자 고름 검체는 Achromobater xylosoxidans와 혼합감염으로 여러 번의 계대 배양과 재검사로 인해 11.3일이 소요되었는데, MALDI-TOF법으로 검사한 경우 한 번에 동정되었다. 4명의 환자는 기저질환이 있는 60세 이상이었고 기회감염과 원내감염의 가능성을 배제할 수 없었으며, 그 중 92일 만에 채취된 검체는 imipenem과 meropenem에 내성이었다. 따라서 O. anthropi처럼 동정이 까다로운 세균은 신속하고 적절한 환자 치료를 위해 MALDI-TOF법을 이용한 검사가 매우 유용할 것으로 사료된다.

• Journal of Magnetics
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• 제19권2호
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• pp.185-191
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• 2014

In this study we evaluated that flow rate changes affect the (time of flight) TOF image and contrast-enhanced (CE) in a three-dimensional TOF angiography. We used a 3.0T MR System, a nonpulsatile flow rate model. Saline was used as a fluid injected at a flow rate of 11.4 cm/sec by auto injector. The fluid signal strength, phantom body signal strength and background signal strength were measured at 1, 5, 10, 15, 20 and 25-th cross-section in the experienced images and then they were used to determine signal-to-noise ratio and contrast-to-noise ratio. The inlet, middle and outlet length were measured using coronal images obtained through the maximum intensity projection method. As a result, the length of inner cavity was 2.66 mm with no difference among the inlet, middle and outlet length. We also could know that the magnification rate is 49-55.6% in inlet part, 49-59% in middle part and 49-59% in outlet part, and so the image is generally larger than in the actual measurement. Signal-to-noise ratio and contrast-to-noise ratio were negatively correlated with the fluid velocity and so we could see that signal-to-noise ratio and contrast-to-noise ratio are reduced by faster fluid velocity. Signal-to-noise ratio was 42.2-52.5 in 5-25th section and contrast-to-noise ratio was from 34.0-46.1 also not different, but there was a difference in the 1st section. The smallest 3D TOF MRA measure was $2.51{\pm}0.12mm$ with a flow velocity of 40 cm/s. Consequently, 3D TOF MRA tests show that the faster fluid velocity decreases the signal-to-noise ratio and contrast-to-noise ratio, and basically it can be determined that 3D TOF MRA and 3D CE MRA are displayed larger than in the actual measurement.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.362-363
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• 2007

The transport property of stabilized amorphous selenium typical of the material used in direct conversion x-ray imaging devices was studied using the moving photo-carrier grating (MPG) technique and time-of-flight (TOF) measurements. For MPG measurement, the electron and hole mobility, and recombination lifetime of a-Se films with arsenic (As) additions have been obtained. For TOF measurement, a laser beam with pulse duration of 5ns and wavelength of 350 nm was illuminated on the surface of a-Se with thickness of $400{\mu}m$.

• Journal of Electrical Engineering and Technology
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• 제13권2호
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• pp.981-988
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• 2018

In order to acquire an accurate TOF, this paper proposes a method that produces TOF by using a mathematical model for the envelope of the received signal obtained from a system dynamic model of ultrasonic transducer. The proposed method estimates the arrival time of the received signal retrospectively by comparing its wave form obtained after triggering point with its mathematical envelope model. Experimental result shows that the error due to variation of triggering point can be dramatically decreased by implementing the proposed method.

• Bulletin of the Korean Chemical Society
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• 제25권12호
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• pp.1791-1800
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• 2004

Angiotensin I, a model decapeptide, was glycosylated and partially hydrolyzed with HCl (6 N, 80 $^{\circ}C$, 4 h), aminopeptidase, and carboxypeptidase Y. A single peptide mass map obtained from truncated peptides in the partial acid hydrolysate of angiotensin and its glycosylation product mixture by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry enabled sequencing of angiotensin by a combinatorial procedure. MALDI-TOF and electrospray ionization (ESI) tandem mass spectrometric results indicate that both the N-terminal amino group of aspartic acid and the guanidinium group of the second residue arginine are glycosylated.

• Nuclear Engineering and Technology
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• 제56권7호
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• pp.2633-2640
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• 2024

The purpose of this study was to investigate the effect of the reflector, surface treatment, and length of scintillation crystals on the performance of a time-of-flight and depth-of-interaction (TOF-DOI) PET detector with a dual-ended readout and to determine the best reflector and surface treatment. Various types of crystal arrays with three different reflectors (ESR, BaSO₄, and Toray), three different lateral surface treatments (all-polished (AP), all-roughened (AR), and partially roughened (PR, three sides polished, and one side roughened)), and two different lengths (20 and 15 mm) were fabricated. The highest light collection efficiency and best energy resolution were achieved using a crystal with a diffuse reflector (BaSO₄ for AP and Toray for AR). In contrast, the best coincidence timing resolution (CTR) was achieved using an AR crystal with a specular reflector (ESR). The best DOI resolution was achieved using an AR crystal with BaSO₄. Moreover, the results measured with the 20 mm long crystals were similar to those measured with the 15 mm long crystals. Therefore, we concluded that the dual-ended readout PET detector employing the crystal with AR lateral surface treatment and ESR was a good candidate for TOF-DOI PET because it provided excellent CTR and adequate DOI resolution.

• 분석과학
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• 제30권1호
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• pp.10-19
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• 2017

Anabolic steroids have similar structures to testosterone, both of which promote the growth of muscle mass and increase strength. However, the side effects of anabolic steroid use may lead to heart attacks or strokes. Additionally, the excessive use of steroids inhibits the production of the sex hormones in the body via a negative feedback loop, which results in testicular atrophy in males and amenorrhea in females. Currently, the method of choice used to test for the presence of anabolic steroids is GC-MS. However, GC-MS methods require chemical derivatization of the steroid sample to ensure compatibility with the analytical method; therefore, analysis of many different samples is difficult and time consuming. Unlike GC-MS, the liquid chromatography-quadrupole-time of flight mass spectrometry (LC-Q-TOF-MS) method is suitable for many samples. Twenty-two different anabolic steroids were analyzed by LC-Q-TOF-MS with various collision energies (CE). Accurate mass spectral data were obtained using a Q-TOF-MS equipped with an electro-spray ionization source and operated in the positive MS/MS mode for several classes of steroids that are often the targets of testing. Based on the collected data, fragmentation pathways were carefully elucidated. The high selectivity and sensitivity of the LC-Q-TOF-MS instrument combined with these fragmentation pathways offers a new approach for the rapid and accurate screening of anabolic steroids. The obtained data from the 22 different anabolic steroids will be shared with the scientific community in order to establish a library to aid in the screening of illegal anabolic steroids.

• Reproductive and Developmental Biology
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• 제32권2호
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• pp.71-79
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• 2008

Surface-enhanced laser desorption and ionization time-of-flight mass spectrometry (SELDI-TOF MS) is one of the recently developed proteomic technologies which is based on capturing proteins and peptides by chemically modified surfaces and highly sensitive for the analysis of complex biological samples. In the present study, to gain insights into oocyte maturation and early embryo development, SELDI-TOF-MS was used to find the protein candidates that are specifically or prominently expressed in porcine oocytes at the in vitro matured metaphase II (MIIl) and germinal vesicle (GV) stages. By selected CM10 chip, 16 candidates were found to be up-regulated in GV stage oocytes compared with in MII stage oocytes, their molecular weights were 8,180 (2 candidates), 10,226 (5 candidates), 15,767 (5 candidates) and 16,770 (4 candidates) Da respectively. And the expression of 29 candidates were higher in MII than in GV stage oocytes, their molecular weight were 10,832 (3 candidates), 17,743 (8 candidates), 20,122 (3 candidates), 22,131 (3 candidates), 24,857 (7 candidates) and 33,507 (5 candidates) Da, respectively. The expression of selected 13 candidates (0.2 and 1.0 % error tolerances) were analyzed using real time RT-PCR. The proteins that differentially regulated during oocyte in vitro maturation in the pigs may be potential biomarkers of oocyte maturation and quality.