• Mass Spectrometry Letters
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• 제12권4호
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• pp.179-185
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• 2021

Collision-induced dissociation (CID) combined with electrospray ionization mass spectrometry (ESI-MS) was used to obtain structural information on rat islet amyloid polypeptide (rIAPP) monomers (M) and dimers (D) observed in the multiply charged state in the MS spectrum. MS/MS analysis indicated that the rIAPP monomers adopt distinct structures depending on the molecular ion charge state. Peptide bond dissociation between L₂₇ and P₂₈ was observed in the MS/MS spectra of rIAPP monomers, regardless of the monomer molecular ion charge state. MS/MS analysis of the dimers indicated that D⁵⁺ comprised M²⁺ and M³⁺ subunits, and that the peptide bond dissociation process between the L₂₇ and P₂₈ residues of the monomer subunit was also maintained. The observation of (M+ b₂₇)⁴⁺ and (M+ y₁₀)³⁺ fragment ions were deduced to originate from the two different D⁵⁺ complex geometries, the N-terminal and C-terminal interaction geometries, respectively. The fragmentation pattern of the [M_rIAPP + M_hIAPP]⁵⁺ MS/MS spectrum showed that the interaction occurred between the two N-terminal regions of M_rIAPP and M_hIAPP in the heterogeneous dimer (hetero-dimer) D⁵⁺ structure.

• Archives of Pharmacal Research
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• 제28권5호
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• pp.592-597
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• 2005

An HPLC/Esl/MS method has been developed to identify and quantify the spirostanol glycosides in the rhizomes of five Polygonatum species. The relative distribution of two steroidal saponins in each extract was established using the selective ion monitoring (SIM) mode via an electrospray ionization (ESI) source. It was found that there were significant differences in the amount of spirostanol glycosides among the Polygonatum Species. The results showed that this method could be used to identify the steroidal saponins in the extracts and differentiate Polygonatum species with high sensitivity and reproducibility in a short time. Fragmentation patterns of the two reference compounds were also discussed with the electrospray ionization multi-stage tandem mass spectroscopy (ESI-MS$^n$).

• 한국축산식품학회지
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• 제41권1호
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• pp.59-70
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• 2021

A method for simultaneous detection of fipronil (F) and its metabolites fipronil desulfinyl (FD), fipronil sulfide (FS), fipronil sulfone (FSO) in chicken eggs was applied and validated. It includes single-step, cheap, effective, rugged, safe-based method (SinChERS) for sample preparation and ultra high performance liquid chromatography coupled with mass spectrometry (UHPLC-MS/MS) for chemical analysis. Results suggested that formic acid enhanced the recovery of 4 target residues and 1% supplementation to acetonitrile gained higher recoveries than that of 5%. SinChERS integrated extraction and clean-up steps into one, with shorter time (1.5 h) to operate and higher recoveries (97%-100%) than HLB, Envi-Carb-NH2 and quik-easy-cheap-effective-rugged-safe method (QuEChERS), and it consumed the smallest volume of extracting solvent (10 mL) as QuEChERS. Quantitative analyses using external standard method suggested the linear ranges of 4 target compounds were 1-20 ㎍/L with R2 >0.9947. The limit of detection (S/N>3) and quantification (S/N>10) were 0.3 ㎍/kg and 1 ㎍/kg. Recoveries ranged from 89.0% to 104.4%, and the relative standard deviations (n=6) at 1, 10, and 20 ㎍/kg were lower than 6.03%. Thirty batches of domestic eggs (500 g each) were detected by the established SinChERS-based UHPLC-MS/MS and no target residues were detected in all samples. The method developed in this study is a rapid, sensitive, accurate and economic way for multi-residue analysis of fipronil and its metabolites in eggs.

• 분석과학
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• 제25권5호
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• pp.292-299
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• 2012

GC/MS (gas chromatography/mass spectrometry)는 훌륭한 분리능과 재현성으로 인해 널리 활용되고 있으며, 정립된 데이터베이스의 활용을 통한 성분 분석에서 활용도가 높다. 또한 HS-SPME (headspacesolid phase micro extraction)법은 용매로 추출을 하지 않은 휘발성 물질의 추출을 하는데 널리 사용되었다. 이 두 방법의 연계는 다양한 시료에서 발생하는 휘발성 성분의 분석에 널리 활용되었다. 위 특징을 이용하여 살아있는 Camponotus japonicus가 분비하는 미량의 페로몬 구성 성분의 분석 방법을 확립하였다. n-Decane, n-undecane, n-tridecane 등의 물질이 미량 페로몬에서 검출되었으며, 이 탄화수소들을 분석하는데 적합한 SPME fiber, 추출 온도, 추출 시간을 최적화하였다. 살아있는 시료를 분석할 수 있기 때문에 특정 현상이 발생하는 그 순간을 분석하는 장점이 있는 한편, 살아있는 시료를 분석하기 때문에 추출 시간 등이 제한된다는 한계점이 있었으나 살아있는 HS-SPME GC/MS 분석방법이 정립된다면 살아있는 시료를 죽일 필요 없다는 점에서 친환경적인 연구의 발전에 해결책이 될 수 있을 것으로 전망한다.

• Mass Spectrometry Letters
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• 제3권1호
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• pp.15-17
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• 2012

Eighteen of the PDE-5 inhibitors and their analogues were analyzed using GC-EI-MS. Fourteen of them could be identified by simple GC-MS method without derivatization, but hydroxyhongdenafil, hydroxyvardenafil, xanthoanthrafil and mirodenafil could not be identified without derivatization for the high polarity due to the presence of hydroxyl groups. N,O-bis(trimethylsilyl) trifluoroacetamide (BSTFA) and N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide (MTBSTFA), widely used trimethylsilyl (TMS) derivatizing reagents, were used to improve the sensitivity of the hydroxylated analogues. And the analytes could be identified by GC-MS after the derivatization.

• 분석과학
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• 제15권5호
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• pp.410-416
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• 2002

본 연구에서는 LC - MS/MS를 이용해 혈장과 뇨중에서 반코마이신을 신속하게 정량분석하는 방법을 개발하였다. 크로마토그래피는 $C_{18}$ XTerra MS 컬럼 ($2.1{\times}30mm$, $3.5{\mu}m$)을 사용하여 분석하였다. 이동상으로는 0.25% 초산이 섞인 10% 아세토니트릴 용액을 사용하였으며, 유속은 $250{\mu}L/min$이다. 반코마이신과 카페인 (내부표준물질)은 multiple reaction monitoring (MRM) 방법을 사용하여 검출하였으며 반코마이신은 precursor ion m/z 725.0 ( $[M+2H]^{2+}$)와 product ion m/z 100.0을 사용하였다. 혈장에서 반코마이신의 검출한계는 1 nM이며 좋은 정확성과 정밀성을 보여주었다. 또한 혈장중에서 반코마이신의 정량범위는 $0.01{\mu}M$ - $100{\mu}M$이다. 혈장과 뇨중에서 반코마이신을 정량하는 이 분석방법은 약물동력학연구 및 관련연구에 성공적으로 적용되었다.

• Journal of Nutrition and Health
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• 제41권4호
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• pp.327-340
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• 2008

This study was designed to investigate the correlation between nutrition status and cardiovascular disease in type 2 diabetes patients with metabolic syndrome. The subjects were 66 patients and divided into Non MS (a group without metabolic syndrome, n = 37) and MS (a group with metabolic syndrome, n = 29). The percentage of patients accompanying metabolic syndrome was 43.9% and family history such as DM, skipping meal and eating speed were higher in MS (P < 0.05) The average values of BMI, body fat (%), waist circumference were significantly higher in patients of MS than that of Non MS. For hamatological values, MS showed higher FRS, HOMA-IR, LDL-Cholesterol, CRP. Percentage of FRS was 21.63% in MS that is relatively higher in comparison with 16.81% in Non MS. Moreover, the incidence of cardiovascular disease appeared 13.8% in MS that is higher than 2.7% in Non MS. The intake of sodium and vitamin E were higher, but the intake of fat, vitamin A and zinc were lower in MS than in Non MS. Close correlations were elucidated among FRS, occurrence of cardiovascular disease, weight, waist circumference, Total-Cholesterol, LDLCholesterol, sodium in both groups. In conclusion, cardiovascular disease risk factors would be higher in type 2 diabetes patients with metabolic syndrome and there were distinctive patterns that were associated with hamatological values, nutrition intake risk factors. This result should be considered when designing nutrition study and intervetion programs.

• Asian-Australasian Journal of Animal Sciences
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• 제13권12호
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• pp.1674-1680
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• 2000

A study was conducted to compare the feeding value of urea treated and untreated mustard straw (MS) for sheep. Treated MS was prepared by adding urea-N at 1.84% and followed by packing in a pit silo for 21 days. Two groups of six empty Avikaline ewes were fed untreated (UTMS) and treated (TMS) mustard straw along with 200 g concentrate per head daily for 90 days. Untreated MS had 0.41% N and the urea treatment increased its N value to 1.58 %. The cell wall constituents were decreased in the TMS except for cellulose which remained unaffected. Dry matter intake of TMS was consistently higher than that of UTMS. Digestibility of DM, OM and fibre fractions of MS improved by the urea treatment. Ewes in both groups were in positive N balance while % N retention was lower in UTMS (26.30%) than in TMS (52.14%). The TMS fed group on average consumed 30.2 g DM, 2.9 g digestible crude protein and $0.2MJ\;DE\;per\;kg\;BW\;day^{-1}$ and maintained their weight whereas, the UTMS fed ewes lost weight. The VFA concentration in rumen liquor was higher in TMS than in UTMS. Total-N, ammonia-N and TCA-precipitable-N were also higher in TMS fed ewes. Blood glucose concentrations in the two groups were similar at initiation of the study. However the glucose concentration of UTMS fed group was significantly (p<0.01) lower than those fed UTMS at the termination of the study. Urea-N concentration was also higher in TMS fed group after 90 days of feeding period. It is concluded that urea treatment of MS improved N value of MS from 0.41% to 1.58% along with sizable improvement in nutritive value and in conjunction with 200 g concentrate, TMS can serve as maintenance ration for sheep. ($ME_{lakt}/ME_{m}=1.46$).

• Bulletin of the Korean Chemical Society
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• 제34권5호
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• pp.1487-1493
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• 2013

Based on the finding that the 2-aminobenzamido group of MS-275 plays a crucial role in inhibiting HDACs through chelation of zinc existing at the active site of HDAC enzymes, novel N-(2-hydroxyphenyl)arylsulfonamide derivatives were synthesized for their potential ability to inhibit HDACs and evaluated for anticancer activity against human breast cancer cell line (MCF-7). Although the synthesized arylsulfonamides have failed to significantly inhibit total HDACs activity, phenyl carbamate-linked arylsulfonamide 10 and benzyl thiocarbamate-linked arylsulfonamide 15 exhibited good anticancer activities, which were only 4.3- and 3.6-fold lower anticancer activities, respectively, than MS-275 that is undergoing phase II clinical trials. These results suggest that these compounds may act as a selective HDAC inhibitor and probably N-(2-hydroxyphenyl) sulfamoyl group may play an important role in interacting with HDAC enzymes through chelation of zinc ion.

• 한국추진공학회지
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• 제18권6호
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• pp.11-18
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• 2014

아산화질소/에탄올 추진제 조합을 사용하는 50 N급 추력기 분사기 인접부에서 shadowgraph 기법을 사용하여 연소 유동장을 가시화하였다. 설계 작동조건에서 폭발성 점화가 일어났으며, 급격히 팽창하는 연소가스에 의해 순간적으로 소염되는 현상이 관찰되었다. 최초 점화로부터 약 83 ms 뒤 추진제 분무는 재점화 되었으며, 그로부터 약 23 ms 후 화염이 안정화되는 것이 관찰되었다. 동일한 시퀀스에서 설계 조건보다 산화제 유량을 증가시킨 경우, 소염 현상 없이 완만한 연소 압력 과도 특성을 보였으며 최초 점화로부터 약 17 ms이내에 화염 안정화가 이루어졌다. 이는 점화 직전의 연소기 내부 미연 추진제 혼합 향상에 의한 것으로 생각되었다.