• 제목/요약/키워드: two internal standards

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Development of Gas Chromatography/Mass Spectrometry for the Determination of Essential Fatty Acids in Food Supplemental Oil Products

  • Ahn, Seonghee;Yim, Yoon-Hyung;Kim, Byungjoo
    • Mass Spectrometry Letters
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    • 제4권4호
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    • pp.75-78
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    • 2013
  • A gas chromatography/mass spectrometric (GC/MS) method was developed as a candidate reference method for the accurate determination of essential fatty acids (linoleic acid, ${\alpha}$- and ${\gamma}$-linolenic acids) in food supplemental oil products. Samples were spiked with three internal standards (stearic acid-$d_{35}$, $^{13}C_{18}$-linoleic acid, and $^{13}C_{18}$-${\alpha}$-linolenic acid). Samples were then subject to saponification, derivatization for methylation, and extraction by organic solvent. For GC/MS measurement, an Agilent HP-88 column, designed for the separation of fatty acid methyl esters, was selected after comparing with other columns as it provided better separation for target analytes. Target analytes and internal standards were detected by selected ion monitoring of molecular ions of their methyl ester forms. The GC/MS method was applied for the measurement of three botanical oils in NIST SRM 3274 (borage oil, evening primrose oil, and flax oil), and measurement results agreed with the certified values. Measurement results for target analytes which have corresponding isotope-labeled analogues as internal standard were calculated based on isotope dilution mass spectrometry (IDMS) approach, and compared with results calculated by using the other two internal standards. Results from the IDMS approach and the typical internal standard approach were in good agreement within their measurement uncertainties. It proves that the developed GC/MS method can provide similar metrological quality with IDMS methods for the measurement of fatty acids in natural oil samples if a proper fatty acid is used as an internal standard.

2가지 내부표준물질을 이용하여 어류시료 중 Octylphenol, Nonylphenol, Bis(2-ethylhexyl)phehalate의 동시정량 (Simultaneous Determination of Octylphenol, Nonylphenol and Bis(2-ethylhexyl)phthalate in Fish Samples Using Two Internal Standards)

  • 김종훈
    • 분석과학
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    • 제14권3호
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    • pp.244-252
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    • 2001
  • 어류근육속에 포함된 nonylphenol(NP), octylphenol(OP), bis(2-ethylhexyl)phtalate(BEHP)의 동시 정량방법을 1-phenyldecanol(PD)과 bis(2-ethylbutyl)phthalate(BEBP) 2가지 내부표준물질을 이용하여 연구하였다. 1-phenyldecanol은 nonyphenol과 octylphenol을 정량하고, bis(2-ethylbutyl)phthalate는 bis(2-ethylhexyl)phthalate를 정량하기 위해 사용하였다. NP와 OP의 경우 $0.2{\sim}20{\mu}g/g$ 농도범위에서 75% 이상의 회수율을 나타냈으며, BEHP는 $0.4{\sim}40{\mu}g/g$ 농도범위에서 102% 이상의 회수율을 보였다. 시료를 밀폐된 배양시험관에서 이염화메탄을 이용하여 추출하고 용매를 이소-헥산으로 바꾸고 aminopropyl 칼럼(2g)을 이용하여 분리한후 GC/MS-SIM 방법으로 분석하였다. 확립된 분석방법을 11점의 한국시료와 3점의 영국시료에 적용하였다. Nonylphenol은 2점의 한국어류시료에서, BEHP는 9점의 한국어류시료에서 검출되었고, 그 농도범위는 각각 $0.02{\sim}0.06{\mu}g/g$$0.18{\sim}2.03{\mu}g/g$이었다. 그러나 영국어류시료에서는 단 1점의 시료에서 BEHP가 검출되었고 그 농도는 $2.99{\mu}g/g$이었다. 이 방법에 의해서 octylphenol은 어떠한 시료에서도 검출되지 않았으며, 이와 같이 2가지 내부표준물질을 이용하는 방법은 각기 다른 특성을 갖는 분석대상물질에 각각의 특성과 유사한 내부표준물질의 사용으로 매우 적은량의 생체 시료에서 보다 정확한 정량이 가능하였다.

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The Impact of Internal Audit Quality on Financial Performance of Yemeni Commercial Banks: An Empirical Investigation

  • HAZAEA, Saddam A.;TABASH, Mosab I.;KHATIB, Saleh F.A.;ZHU, Jinyu;AL-KUHALI, Ahmed A.
    • The Journal of Asian Finance, Economics and Business
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    • 제7권11호
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    • pp.867-875
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    • 2020
  • Quality internal audit (IA) plays a crucial role in accountability, transparency and preserving public properties. This paper gives a brief background of the IA system in Yemen and examines its impact with regards to financial performance in Yemeni commercial banks based on five factors: (i) independence of IAs, (ii) adherence to IA standards, (iii) governance principles implementation, (iv) size of the IA, and (v) frequency of internal audits committees' meetings. The primary data for the study were collected through a questionnaire prepared for this purpose. Fifty questionnaires were distributed out of which forty-two were retrieved and valid in the analysis process. For the empirical analysis, descriptive analysis and T-test were used for verification of the research hypotheses. Results revealed that sticking to standards internal audit, internal auditors' independence and quality governance have significant impact on banks' financial performance, while the size of internal audits committees, as well as their meeting, frequently has insignificant positive impact on banks' performance. Moreover, the country results show that the use of automated internal audit in banks has an impact on improving financial performance. This article provides avenues for further studies, mainly in developing countries, including Yemen, in quality internal audit and financial performance.

대기 중 다환방향족탄화수소(PAHs)의 측정.분석 신뢰도 향상에 관한 고찰 (Study on Improvement in Reliability of Measurement and Analysis for Polycyclic Aromatic Hydrocarbons in the Atmosphere)

  • 이민도;임용재;이상욱;공부주;이상덕;한진석
    • 한국대기환경학회지
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    • 제23권5호
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    • pp.515-525
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    • 2007
  • In this study, various techniques for measurement and analysis of PAHs in the ambient air were verified in order to select a more reliable method. Sampling and analysis of PAHs were done by the EPA TO-13a method. QA/QC of the measurement was conducted to minimize errors in sampling and analyzing processes. The linearity of calibration curve of the PAH standards was good ($R^2{\geq}0.99$). Audit accuracy was evaluated using 5 internal standards of PAHs ($Naphthalene-d_8,\;Acenaphthene-d_{10},\;Phenanthrene-d_{10},\;Chrysene-d_{12},\;Perylene-d_{12}$). Relative standard deviations of the internal standard of the PAHs were ranged from 6.22% for $acenaphthene-d_{10}$ to 8.11% for $chrysene-d_{12}$. To evaluate the surrogate recoveries, two field surrogate standards of PAHs ($fluoranthene-d_{10},\;benzo(a)pyrene-d_{12}$) and two extract surrogate standards of the PAHs ($fluorene-d_{10},\;pyrene-d_{12}$) were spiked into all samples before field sampling and sample extraction, respectively. Recoveries of field the surrogate standards ranged from $80.4{\pm}12.2%$ for $fluoranthene-d_{10}$ to $66.2{\pm}12.8%$ for $benzo(a)pyrene-d_{12}$. Extraction recoveries of the surrogate standards ranged from $70.4{\pm}10.2%$ for $fluorene-d_{10}$ to $77.6{\pm}10.8%$ for $pyrene-d_{10}$. The detection limit of benzo(a)pyrene among 16 PAHs standards for quantitation was 20 pg.

Cost-Benefit Analysis and Challenges of Implementing FSC Standards in Rubber Plantations in Southern Thailand

  • KONGMANEE, Chaiya;AHMED, Ferdoushi;LONGPICHAI, Onanong
    • The Journal of Asian Finance, Economics and Business
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    • 제7권12호
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    • pp.423-431
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    • 2020
  • This study examines the cost and benefit (i.e., income) of the Forest Stewardship Council (FSC) rubber plantations in Thailand. The study attempts to identify the challenges to the implementation of FSC standards in rubber plantations in the country. A total of 60 rubber farmers in two Southern provinces, namely, Songkhla and Rayong, were interviewed through a standardized questionnaire to gather primary data. The study found that small-, medium- and large-sized FSC rubber plantations were worth investing in. All sizes of rubber plantations had similar values of benefit cost ratio (BCR). It was also found that the values of the discount payback period (DPP) of the three forms of FSC rubber plantations were 9-12 years, while the large rubber plantations had the highest internal rate of return (IRR) (19.0%). It implies that the large-size plantations had the highest values. The rubber farmers in the study area reported that they are facing a number of problems and hardships in implementing FSC standards, lacking knowledge and understanding of FSC, especially for preparing documentation. Therefore, the Thai government should take proper policy initiatives to remove all the problems and barriers in implementing FSC standards for the sustainable rubber production in the country.

제트팬 설치 간격과 재유입 현상 분석을 위한 모형실험 (Model Test for the Determination of Distances between Jet-fans and Analysis of Recirculation)

  • 권오상;윤찬훈;윤성욱;김진
    • 한국터널지하공간학회 논문집
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    • 제8권4호
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    • pp.335-344
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    • 2006
  • 국내에서 제트팬 설치 간격 기준으로 사용되고 있는 일본도로공단 기준은 제트팬의 구경에 따라 설치간격을 제시하고 있지만 국제 상설도로 협회(PIARC)에서는 터널 직경에 10배를 유지할 것을 권장하고 있다. 이 기준들에 의해 결정된 설치 간격은 최대 약 2배 정도의 차이를 나타내고 있으며 이러한 설치 간격의 차이는 터널 환기 방식 선정에 불리한 요건으로 작용될 수 있기 때문에 터널 내부의 기류분석을 통한 적정 설치 간격 기준이 필요하다. 본 논문에서는 Froude 상사이론에 기초하여 아크릴 재질의 축소비 1/40의 모형 터널(직경 215mm, 연장 6.9m)과 모형 제트팬(구경 26.3mm, 31.6mm)을 제작하여 터널 내부에서의 기류분석을 위해 터널연장을 따라서 압력과 속도의 변화를 측정하였고, 제트팬 가동시 제트팬 주위에서 외부 공기의 영향으로 발생될 수 있는 재유입 현상을 확인하기 위해서 제트팬 주변에서 압력변화를 측정하였다. 모형실험 결과에서는 터널 내부기류는 제트팬 구경에 영향을 받지 않고 터널직경에 약 9배 정도가 되는 지점에서 압력과 속도의 변화가 안정되는 것으로 나타났으며 제트팬이 가동되면서 발생되는 재유입 현상을 확인할 수 있었다. 이러한 결과를 통해 터널 내부에서의 제트팬 설치 시에는 터널 직경에 약9배 이상을 확보해야 한다고 판단된다.

복부수술 환자간호의 질평가 도구 개발 (Development of an evaluation tool for the quality of nursing care in abdominal surgery patients)

  • 이병숙
    • 간호행정학회지
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    • 제4권1호
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    • pp.107-127
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    • 1998
  • The purpose of this study was to develop an evaluation tool for the quality of nursing care in abdominal surgery patient. The target subjects of the tool were adult patients having abdominal surgery under general anesthesia. Process-outcome framework was selected for the development of the tool in this study. The results were as follows. 1. Nine standards. 40 criteria and 88 indicators were developed. A standard was summary statement of the ideal level of excellencein a dimension of quality of nursing care. which could be evaluated by criteria. Several criteria indicated a specific standard and each criterion could be measured by observable and measurable indicators. 2. The standards were divided into two dimensions. One was process dimension which contained four standards(23 criteria), the other was outcome dimension which contatined five standards(17 criteria). 3. Average CVI was .985 at 9 standards. .947 at 40 criteria. and .987 at 88 indicators. 4. The evaluation tool for the quality of nursing care in abdminal surgery patients was a criterion-referenced tool. And data collection methods of the tool were investigation of patient's record and interview( or questionnaire) with the patients. 5. Interrater reliabilities of the tool were ; r= .7572 (agreement between two raters), and pI=.8487 (intraclass correlation between five raters who rated the 84 patients). 6. Internal consistency reliability ${\alpha}$ was .6194, which was obtained from 32 criteria. Eight criteria were missed in the analyzing process because of data omission. 7. Scores of the process and the outcome dimensions showed significant. but low correlation(r= .3759, p < .001). 8. There were significant differences in total scores between the hospitals and the departments of surgery(F = 15.233. p .0001). There was also significant interaction effect between hospitals and departments to total score(F = 8.396. p = .0001). Construct validity of the toool was verified by the known-group method. these kinds of difference were expected by the nursing experts participated in the study. From these results, more specific patient classification is suggested for the development of evaluation tool of the quallity of nursing care. And indicators to be used for objective measurement for the quality of nursing care must be developed.

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Development of nitrogen and oxygen certified reference materials in 10 μmol/mol for the purity evaluation

  • Ahn, Byung Soo;Moon, Dong Min;Lee, Jin Bok;Kim, Jin Seog;Lee, Jin-Hong;Hong, Kiryong
    • 분석과학
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    • 제33권2호
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    • pp.68-75
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    • 2020
  • We have developed 10 μmol/mol nitrogen and oxygen certified reference materials (CRMs) in helium, as a SI-traceable gas standard for a quantifying of impurities in pure gases for the first time in Korea. The standard gas mixtures of nitrogen and oxygen were prepared in 5000 μmol/mol and sequentially were diluted to 250 μmol/mol and 10 μmol/mol according to the gravimetric preparation. In each dilution step, two cylinders of CRMs were prepared. The verification of internal consistency among the prepared gas mixtures was performed by using GC-TCD. The amount fractions and those expanded uncertainties (k = 2) of nitrogen and oxygen in the standard gas mixtures were (10.12 ± 0.08) μmol/mol and (10.18 ± 0.08) μmol/mol for nitrogen, and (9.88 ± 0.06) μmol/mol and (9.94 ± 0.06) μmol/mol for oxygen, respectively. We have conducted a purity assessment of two commercial helium gases using developed CRMs. As the results of the purity assessment, nitrogen and oxygen were detected by (1.66 ± 0.03) μmol/mol and (0.31 ± 0.02) μmol/mol, respectively, as the impurities in one of the pure helium.

Computational method in database-assisted design for wind engineering with varying performance objectives

  • Merhi, Ali;Letchford, Chris W.
    • Wind and Structures
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    • 제32권5호
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    • pp.439-452
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    • 2021
  • The concept of Performance objective assessment is extended to wind engineering. This approach applies using the Database-Assisted Design technique, relying on the aerodynamic database provided by the National Institute of Standards and Technology (NIST). A structural model of a low-rise building is analyzed to obtain influence coefficients for internal forces and displacements. Combining these coefficients with time histories of pressure coefficients on the envelope produces time histories of load effects on the structure, for example knee and ridge bending moments, and eave lateral drift. The peak values of such effects are represented by an extreme-value Type I Distribution, which allows the estimation of the gust wind speed leading to the mean hourly extreme loading that cause specific performance objective compromises. Firstly a fully correlated wind field over large tributary areas is assumed and then relaxed to utilize the denser pressure tap data available but with considerably more computational effort. The performance objectives are determined in accordance with the limit state load combinations given in the ASCE 7-16 provisions, particularly the Load and Resistance Factor Design (LRFD) method. The procedure is then repeated for several wind directions and different dominant opening scenarios to determine the cases that produce performance objective criteria. Comparisons with two approaches in ASCE 7 are made.

신경외과 중환자 간호의 질평가 도구개발 (Development of an evaluation tool for the quality of nursing care in neurosurgical intensive care unit patients)

  • 김남영;장금성
    • 간호행정학회지
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    • 제7권2호
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    • pp.285-300
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    • 2001
  • To meet standards for high quality of care and satisfied customers, an evaluation tool about nursing care is necessary. And, We need to evaluate our practice continuously for the improvement in quality and outcomes. This study was intended to develop an evaluation tool about nursing care in NSICU, and was progressed of 3 steps; development, content validity verification and reliability verification. Data were obtained and analysed from Feb. To April, 2000. Development process of the study was as follows A preliminary list was made item by item on the basis of clinical Experience, literature review and patients' record review. Then the standards, criteria and indicators of preliminary evaluation tool were set by 5 clinical nursing panel, and their content validity was reviewed by 27 ICU nurses. Finally, an evaluation tool was developed and verified the reliability at c-university hospital located in Kwang-Ju. The results of this was as follows 1) The evaluation tool of this study developed 8 standards, 39 criterias and 106 indicators. The standards were divided into two dimensions. One was process dimension which contained 4 standards(26 criteria), The other was outcome dimension which contained 4 standards(13 criteria). 2) the Average content validity of the tool was 3.39 at standards, 3.55 at criteria and 3.51 at indicators. 3) Interrater reliability of the tool is r=.7993(p<.001) & internal consistency reliability ${\alpha}$ is .6031 4) Scores of NSICU Patients who participated in this study were 57 at total mean score, 58 at process mean score and 56 at outcome mean score The evaluation tool developed in this study seems to be useful in evaluation nursing practice appropriately for the improvement of nursing care in NSICU. I hope that this evaluation tool can be used effectively in NSICU as an intervention for the improvement of quality control.

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