• 동아시아경상학회지
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• 제9권3호
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• pp.71-82
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• 2021

Purpose - The purpose of this study is to examine the intermediary role of job satisfaction between job autonomy and job performance and whether the process was adjusted based on the work context. Research design, data, and methodology - This study was conducted by sample survey method on 334 supervising engineers. Data analysis methods were frequency analysis, confirmatory factor analysis, reliability analysis, correlation analysis, and structural equation model analysis. Result - The results of this study suggest that: (1) after controlling for age, position, and working years, job autonomy had a significant positive impact on job performance, (2) job autonomy can not only directly affect job performance but also indirectly affect performance through job satisfaction, (3) job satisfaction has an intermediary effect on job autonomy and job performance, and (4) the relationship between job autonomy and job satisfaction is moderated by the work context, and the result showed a negative moderating effect. Conclusion - This study suggests that job autonomy significantly improves job performance, and the higher job autonomy a supervising engineer has, the more satisfied they are with their work, thus enriching the precursor research on dynamic changes in job performance. When the working environment is poor, supervisors are more sensitive to the perception of job autonomy and have a stronger impact on job satisfaction and performance.

• 한국산업보건학회지
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• 제17권3호
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• pp.235-244
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• 2007

By comparing the proteins from the workers exposed to styrene with the ones from controls, it may be possible to identify proteins that play a role in the occurrence and progress of occupational disease and thus to study the molecular mechanisms of occupational disease. In order to find the biomarkers for assessing the styrene effects early, before clinical symptoms develop and to understand the mechanisms of adverse health effects, we surveyed 134 employees, among whom 52 workers(30 male and 22 female) were chronically exposed to styrene in 10 glass-reinforced plastic boat manufacturing factories in Korea and 82 controls had never been occupationally exposed to hazardous chemicals including styrene. The age and drinking habits and serum biochemistry such as total protein, BUN and serum creatinine in both groups were significantly different. Exposed workers were divided into three groups according to exposure levels of styrene(G1, below 1/2 TLV; G2, 1/2 TLV to TLV; G3, above TLV). The mean concentration of airborne styrene in G1 group was $10.93{\pm}11.33ppm$, and those of urinary mandelic acid(MA) and phenylglyoxylic acid(PGA) were $0.17{\pm}0.21$ and $0.13{\pm}0.11g/g$ creatinine, respectively. The mean concentration of airborne styrene in G2 and G3 groups were $47.54{\pm}22.43$ and $65.33{\pm}33.47ppm$, respectively, and levels of urinary metabolites such as MA and PGA increased considerably as expected with the increase in exposure level of styrene. The airborne styrene concentration were significantly correlated to the urinary concentration of MA(r=0.784, p=0.000) and PGA(r=0.626, p<0.001). In the 2D electrophoresis, the concentration of five proteins including complement C3 precursor, alpha-1-antitrypsin(AAT), vitamin D binding protein precursor(DBP), alpha-1-B-glycoprotein(A1BG) and inter alpha trypsin inhibitor(ITI) heavy chain-related protein were significantly altered in workers exposed to styrene compared with controls. While expression of complement C3 precursor and AAT increased by exposure to styrene, expression of DBP, A1BG and ITI heavy chain-related protein decreased. These results suggest that the exposure of styrene might affects levels of plasma proteinase, carriers of endogenous substances and immune system. In particular, increasing of AAT with the increase in exposure level of styrene can explain the tissue damage and inflammation by the imbalance of proteinase/antiproteinase and decrease of DBP, A1BG and ITI heavy chain-related protein in workers exposed to styrene is associated with dysfunction and/or declination in immune system and signal transduction

• Journal of Korean Neurosurgical Society
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• 제59권5호
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• pp.437-441
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• 2016

Objective : Recently, regenerative therapies have been used in clinical trials (heart, cartilage, skeletal). We don't make use of these treatments to spinal cord injury (SCI) patients yet, but regenerative therapies are rising interest in recent study about SCI. Neural precursor/stem cell (NPSC) proliferation is a significant event in functional recovery of the central nervous system (CNS). However, brain NPSCs and spinal cord NPSCs (SC-NPSCs) have many differences including gene expression and proliferation. The purpose of this study was to investigate the influence of neural growth factor (NGF) on the proliferation of SC-NPSCs. Methods : NPSCs ($2{\times}10^4$) were suspended in $100{\mu}L$ of neurobasal medium containing NGF-7S (Sigma-Aldrich) and cultured in a 96-well plate for 12 days. NPSC proliferation was analyzed five times for either concentration of NGF (0.02 and 2 ng/mL). Sixteen rats after SCI were randomly allocated into two groups. In group 1 (SCI-vehicle group, n=8), animals received 1.0 mL of the saline vehicle solution. In group 2 (SCI-NGF group, n=8), the animals received single doses of NGF (Sigma-Aldrich). A dose of 0.02 ng/mL of NGF or normal saline as a vehicle control was intra-thecally injected daily at 24 hour intervals for 7 days. For Immunohistochemistry analysis, rats were sacrificed after one week and the spinal cords were obtained. Results : The elevation of cell proliferation with 0.02 ng/mL NGF was significant (p<0.05) but was not significant for 2 ng/mL NGF. The optical density was increased in the NGF 0.02 ng/mL group compared to the control group and NGF 2 ng/mL groups. The density of nestin in the SCI-NGF group was significantly increased over the SCI-vehicle group (p<0.05). High power microscopy revealed that the density of nestin in the SCI-NGF group was significantly increased over the SCI-vehicle group. Conclusion : SC-NPSC proliferation is an important pathway in the functional recovery of SCI. NGF enhances SC-NPSC proliferation in vitro and in vivo. NGF may be a useful option for treatment of SCI patients pending further studies to verify the clinical applicability.

• 한국진공학회지
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• 제7권1호
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• pp.51-58
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• 1998

Traveling wave reactor atomic layer epitaxy(ALE) 방법으로 ZnS와 ZnS:Tb박막을 성장하고 성장 조건에 따른 박막 특성을 연구하였다. ZnS박막의 precursor로는 ZnCl2와 H2S를 이용하였으며, 기판 온도 400-$500^{\circ}C$범위에서 성장하였다. 본 연구 논문에서는 성장온 도에 따른 ZnS박막의 결정성의 변화와 precursor에 의한 Cl유입량의 변화를 살펴보고 투과 전자현미경과 주사형 전자현미경으로 ZnS박막의 표면 형상과 미세구조를 관찰하였다. 연구 결과에 의하면 ALE에 의하여 매우 균일하고 hexagonal 2H구조의 결정성이 향상되었다. 성 장온도 $400^{\circ}C$에서 약 9at.%, $500^{\circ}C$에서 약 1at.%의 Cl이 유입되었으며, 박막 내에 유입된 Cl 은 표면으로의 segregation현상을 나타내었다. 또한 electroluminescent 소자의 녹색 형광재 료인 ZnS:Tb을 Tb precursor로 tris(2,2,6,6-tetramethyl 3,5-heptandionato)terbium을 이용하 여 성장하고 박막 결정성과 박막 내 불순물이 유입되는 경향 등을 연구하였다. Auger electron spectroscopy분석 결과에 의하면 0.5at.%의 Tb이 표함된 AnS:Tb박막은 C은 거의 포함하고 있지 않았으나 O은 약 1at.%정도 포함되어 있었다. ZnS:Tb박막은 Tb과 소량의 O 을 함유하고 있음에도 불구하고 결정성은 우수한 hexagonal구조를 유지하고 있었다.

• 분석과학
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• 제16권6호
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• pp.488-498
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• 2003

LC/MS/MS를 이용하여 발기부전 (impotence) 치료제인 sildenafil 및 유사체인 homosildenafil, vardenafil, tadalafil을 분석하는 방법을 확립하였다. 이온화 방법으로는 electrospray ionization (ESI)와 atmospheric pressure chemical ionization (APCI) 방법을 사용하였으며 최대 감도와 재현성을 나타내는 조건을 찾기 위하여 여러 가지 파라미터를 변화시켜서 비교하였다. MRM (multiple reaction monitoring)을 위한 적절한 생성이온 (product ion)을 얻기 위하여 ESI 방법에서는 capillary voltage, cone voltage, extractor, entrance, RF lens를 변화시켰으나 전구이온 (precursor ion)을 제외한 뚜렸한 토막이온 (fragment ion)은 생성되지 않았다. 한편, APCI 방법의 경우 entrance, collision energy, exit, corona voltage, cone voltage, extractor, RF lens, cone gas, desolvation gas를 변화시켰을 때 다른 파라미터들의 변화에 따른 전구이온을 제외한 product ion 생성 패턴의 변화는 감지되지 않고 단지 RF lens 조건의 변화에서 precursor ion을 비롯한 토막이온들의 생성과 더불어 S/N의 증가로 인한 검출 한계의 향상이 나타났다. HPLC에서의 최적 분리 조건과 질량 분석기에서 최대 감도를 나타내는 이동상 조건도 조사되었는데 10 mM ammonium formate (pH 4.8):acetonitrile=70:30 의 등용매 용리조건이 좋은 감도를 나타내었으며, 최적의 방법인 ESI-MRM 방법에서 검출한계 (S/N>5)는 sildenafil은 $0.10{\mu}g/mL$, homosildenafil은 $0.025{\mu}g/mL$, vardenafil은 $0.025{\mu}g/mL$ 그리고 tadalafil은 $0.25{\mu}g/mL$이었다.

• 대한약리학회지
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• 제31권2호
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• pp.241-250
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• 1995

Protein B23 is one of the major nucleolar phosphoproteins associated with pre-ribosomal particles, and is localized in the granular region of the nucleolus. Recent studies suggest that protein B23 shuttles between nucleus and cytoplasm and also interacts with HIV Rev. These findings indicate that protein B23 is important in nucleocytoplasmic relationship and viral replication. However, the exact function of protein B23 is not clear yet. In acute nucleolar hypertrophy of rat liver, treated with thioacetamide, there was observed an increase of not only protein B23 but also B23-like protein p45 when anti-B23 monoclonal antibody (MAb) was used for identification. On the basis of the large B23 specific epitope structure composed of 68 amino acids, a hypothesis was formulated to examine that p45 is the pre-B23 resulting from excessive production of B23. In an attempt to investigate the precursor of B23, we analyzed the subcellular fractions and microsomal subfractions. Subsequently, we analyzed the finger printings of B23-like proteins using the tryptic peptide mapping. The results are summarized: 1) Using B23 MAb, we observed the presence of B23-like proteins in nucleolar fraction, nucleoplasmic fraction and microsomal fraction. 2) In the further microsomal subfractionation, we could partially purify B23-like protein in 2M layer of sucrose gradient. 3) When ion exchange chromatography was employed, there were protein species 80kDa(p80), 65kDa(p65) and 60kDa(p60). 4) Based on the tryptic map analysis of $^{125}I$ labeled proteins, the similarity between B23 and p80 was found only in 9 out of 14(B23) and 21(p80) peptides, and difference was found in the remaining peptides. p80 and p60 had 18 common peptides, and all the peptides of p60 were similar to those of p80. From these results, it is proposed that p45 is an abnormal metabolite resulting from carcinogenesis by thioacetamide, and it is not the precursor of B23. In addition, we suggest that p80 may be a precursor of p45.

• 한국재료학회지
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• 제9권3호
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• pp.244-250
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• 1999

새로운 TiN 선구체인 TEMAT(tertrakis etylmethylamino titanium)과 암모니아를 이용하여 TiN 박막을 형성하였다. 단일 증착원으로 증착시킨 경우에는 $70~1050\AA$/min의 증착률을 얻을 수 있었으며 증착온도에 지배를 받았다. $275^{\circ}C$의 증착온도에서 $0.35\mu\textrm{m}$의 접촉창에서 약 90%의 도포성을 얻을 수 있었다. TEMAT에 암모니아를 첨가하였을 때 단일증착원에서 $3500~6000\mu\omega-cm$정도의 갑을 나타내던 비저상이 ~$800\mu\omega-cm$ 정도로 낮아졌으며 대기중 막의 안정성도 향상되었다. AES의 분석결과에서도 암모니아의 첨가로 현저한 산호와 탄소 함량의 감소를 나타내었다. 그러나 암모니아의 유량을 증가시킬수록 $0.5\mu\textrm{m}$ 접촉창에서 나타난 tiN 박막의 도포성은 감소하였고 이는 TEMAT와 암모니아의 기상 반응에의한 높은 첩착계수를 가진 중간 생성물의 형성에 의한 것으로 생각된다. 반응 부산물에 대한 분석은 QMS에 의해 이루어 졌으며 transamination 반응에 의한 TiN 증착 기구를 제시하였다. 추가적으로 XPS 분석으로 TEMAT와 암모니아의 반응에 의해 만들어지는 탄소는 금소기 탄소였으며 $\beta$-수소 반응이 transamination 반응과 경쟁적으로 일어남을 나타내었다.

• Genomics & Informatics
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• 제12권1호
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• pp.21-34
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• 2014

A visual analysis approach and the developed supporting technology provide a comprehensive solution for analyzing large and complex integrated genomic and biomedical data. This paper presents a methodology that is implemented as an interactive visual analysis technology for extracting knowledge from complex genetic and clinical data and then visualizing it in a meaningful and interpretable way. By synergizing the domain knowledge into development and analysis processes, we have developed a comprehensive tool that supports a seamless patient-to-patient analysis, from an overview of the patient population in the similarity space to the detailed views of genes. The system consists of multiple components enabling the complete analysis process, including data mining, interactive visualization, analytical views, and gene comparison. We demonstrate our approach with medical scientists on a case study of childhood cancer patients on how they use the tool to confirm existing hypotheses and to discover new scientific insights.

• Journal of Microbiology and Biotechnology
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• 제21권6호
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• pp.599-603
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• 2011

A new geldanamycin (GDM) derivative was discovered and isolated from the fermentation broth of Streptomyces hygroscopicus 17997. Its chemical structure was elucidated as thiazinogeldanamycin by LC-MS, sulfur analysis, and NMR. The addition of cysteine to the fermentation medium significantly stimulated the production level of thiazinogeldanamycin, suggesting cysteine as a precursor of thiazinogeldanamycin production. Although showing a decreased cytotoxicity against HepG2 cancer cells, thiazinogeldanamycin exhibited an improved water solubility and photostability. Thiazinogeldanamycin may represent the first natural GDM derivative characterized so far that uses GDM as its precursor. Its appearance also clearly indicates that an appropriate end-point of fermentation is of critical importance for the maximal production of GDM by Streptomyces hygroscopicus 17997.

• Bulletin of the Korean Chemical Society
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• 제29권8호
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• pp.1491-1494
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• 2008

A novel platinum aminoalkoxide complex, Pt$(dmamp)_2$ has been prepared by the reaction of cis-$(py)_2PtI_2$ with two equivalents of Na(dmamp) (dmamp = 1-dimethylamino-2-methyl-2-propanolate). Single-crystal X-ray crystallographic analysis shows that the Pt(dmamp)2 complex keeps a square planar geometry with each two nitrogen atoms and two oxygen atoms having trans configuration. Platinum films have been deposited on TaN/ Ta/Si substrates by metal organic chemical vapor deposition (MOCVD) using Pt$(dmamp)_2$. As-deposited platinum thin films did not contain any appreciable amounts of impurities except a little carbon. As the deposition temperature was increased, the films resistivity and deposition rate increased. The electrical resistivity (13.6 $\mu\Omega$cm) of Pt film deposited at 400 ${^{\circ}C}$ is a little higher than the bulk value (10.5 $\mu\Omega$cm) at 293 K. The chemical composition, crystalline structure, and morphology of the deposited films were investigated by X-ray photoelectron spectroscopy, X-ray diffraction, and atomic force microscopy.