• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.21 no.2
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• pp.116-122
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• 2011

Human occupational exposure to n-hexane has been associated with neurobehavioral symptoms such as depression, irritablity, acute irritation symptom, concentration disturbance and fatigue. Effects of monoamine oxidase (MAO) B and serotonin transporter receptor (5-HTTR) polymorphisms on the neurobehavioral symptoms were investigated in 70 male workers from TV and computer monitor manufacturing plants exposed to n-hexane. Neurobehavioral symptoms were assessed through a self-reported questionnaire and ambient level of n-hexane was measured by NIOSH method. Blood and urine were collected from each workers to determine the MAO(B), 5-HTTR and urinary 2,5-hexanedione(2,5-HD). The mean concentration of volatile n-hexane was $18.8{\pm}28.8ppm$ and that of urinary 2,5-HD was $1.07{\pm}1.47mg/g$ creatinine. Statistically significant associations with sexual disturbance were age and smoking. The frequencies of MAO(B) AA, AG and GG were 18.6%, 45.7% and 35.7%, respectively, and the frequencies of 5-HTTR ll, ls and ss genotype were 82.9%, 15.7% and 1.4%, respectively. MAO (B) gene polymorphisms had susceptibility to the neurobehavioral symptoms such as fatigue, concentration disturbance, irritability and acute irritation symptom and 5-HTTR gene polymorphism had susceptibility to the sleep disturbance and acute irritation symptom. On multiple logistic regression analysis for the neurobehavioral symptoms, memory disturbance was significantly associated with smoking(OR=6.752, 95% CI=37.46) and drinking(OR=4.033, 95% CI=1.252-12.98), emotional lability was MAO(B) genotype(OR=0.412, 95% CI=0.170-0.996), fatigue (OR=1.011, 95% CI=1.000-1.021) and acute irritation(OR=0.990, 95% CI=0.981-1.000) were working duration and sexual disturbance were significantly associated with age(OR=1.208, 95% CI=1.042-1.399), ambient n-hexane(OR=1.077, 95% CI=1.005-1.154) and 2,5-HD(OR=0.186, 95% CI=0.041-0.841). This finding implies that the MAO (B) and 5-HTTR polymorphisms may affect susceptibility for specific neurobehavioral symptoms associated with n-hexane exposure in workers.

• International Journal of Industrial Entomology and Biomaterials
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• v.36 no.1
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• pp.15-24
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• 2018

N-glycosylation is an important posttranslational modification that results in a variety of biological activities, structural stability, and protein-protein interactions. There are still many mysteries in the structure and function of N-glycans, and detailed elucidation is necessary. Baculovirus expression system (BES) is widely used to produce recombinant glycoproteins, but it is not suitable for clinical use due to differences in N-glycan structure between insects and mammals. It is necessary to develop adequate model glycoproteins for analysis to efficiently alter the insect-type N-glycosylation pathway to human type. The previous research shows the recombinant alpha 1-acid glycoprotein (${\alpha}1AGP$) secreted from silkworm cultured cells or larvae is highly glycosylated and expected to be an excellent research candidate for the glycoprotein analysis expressed by BES. Therefore, we improved the ${\alpha}1AGP$ to be a better model for studying glycosylation. The modified ${\alpha}1AGP$ (${\alpha}1AGP{\Delta}$) recombinant protein was successfully expressed and purified by using BES, however, the expression level in silkworm cultured cells and larvae were lower than that of the ${\alpha}1AGP$. Subsequently, we confirmed the detailed profile of N-glycan on the ${\alpha}1AGP{\Delta}$ by LS/MS analysis the N-glycan structure at each glycosylation site. These results indicated that the recombinant ${\alpha}1AGP{\Delta}$ could be usable as a better model glycoprotein of N-glycosylation research in BES.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.27 no.2
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• pp.83-90
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• 1997

This study was performed to demonstrate the effect of linear or nonlinear contrast enhancement on subtraction images. Three different textures were radiograped on dental film. The first radiograph was taken without the presence of an object. the second, which showed trabucular bone, was taken of the molar area of a human. the third radiograph was taken of the coronal part of molars. Each film was digitized into a 1312 x 1024 pixel x 8 bit depth matrix by means of a Nikon 35 mm film scanner(LS-3510AF, Japan) with fixed gain and internal dark current correction to maintain constant illumination. The scanner was interfaced to a Macintosh Le ill computer(Apple Computer, Charlotte, N.C) This resulted in three pairs of images, including different textures-plain, bone and enamel. Digital regular, linearly and nonlinearly enhanced subtraction was performed. Computer software was ,used to simulate lesions in the shape of a 2D-Gaussian curve on each of a pair of images. The each subtraction images were presented in a random sequence to two groups of 10 observers(students and dentists). ROC analysis was used to compare observer performance. The following results were obtained ; 1. All of LCE subtraction, equalized subtraction and regular subtraction images of plain texture were diagnosed the best by far. 2. The data revealed a siginificant LCE effect in both the student group and the expert group. 3. Clinical expertise was a helphul factor for the observers in this study.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.27 no.1
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• pp.17-24
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• 1997

The purpose of the present study was to use digital profile image features and digital image analysis of fixed-dimension bone regions, extracted from standardized periapical radiographs of the maxilla, to determine whether differences exist in alveolar bone of younger women(mean age: 59.23±7.34 years) and just menopaused women(mean age: 59.23±7.34). Periapical films were used from two groups of 20 randomly selected women. None of the subjects had a remarkable medical history. To simplify protocol, we chose one interproximal bone area between the maxillary right canine and lateral incisor for study. Ech film was digitized into a 1312 x 1024 pixel x 8 bit depth matrix by means of a Nikon 35 mm film scanner(LS-35lOAF, Japan) with fixed gain and internal dark current correction to maintain constant illumination. The scanner was interfaced to a Macintosh LC III computer(Apple Computer, Charlotte, N.C.). Area and profile orientation were selected with a NIMH Image 1.37(NIH Research Services Branch, Bethesda, Md.). Histogram features were extracted from each profile and area. The results of this study indicate that mean pixel intensities didn't differ significantly between two groups and there was a high correlarion-coefficient between digitized radiographic profile features and area features.

• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.4
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• pp.285-296
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• 2017

This paper proposes an improved modulation scheme for the medium voltage modular multi-level converter (MMC), which operates in the nearest level control and applies in the medium voltage direct current (MVDC) system. In the proposed modulation scheme, the offset (neutral-to-zero output) voltage is adjusted, with the phase voltage magnitude, thereby maintaining a constant value with N+1 level in the controllable modulation index (MI) range. In order to confirm the proposed scheme's validity, computer simulations for the 22.9 kV - 25 MVA MMC were performed with PSCAD/EMTDC, as well as hardware experiments for the 380 V - 10 kVA MMC. The proposed modulation scheme offers to build a constant pole voltage regardless of the MI value, and to build a phase voltage with improved total harmonic distortion (THD).

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.2
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• pp.193-201
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• 2011

Recently, mechanical reliabilities including a drop test have been a hot issue. In this paper, solder balls with new components which are Sn-3.0Ag-0.5Cu and Sn-1.0Ag-0.5Cu-0.05N are introduced, and board level drop test for them are conducted under JEDEC standard in which the board with 15 flip chips is dropped as 1,500g acceleration during 0.5ms. The drop simulations are studied by using a implicit method in the ANSYS LS-DYNA, and modal analysis is made. Through both analyses, the solder balls with new components are evaluated under the drop. It is found that the maximum stress of each chip is occurred between the solder ball and the PCB, and the highest value among the maximum stresses in the chips is occurred on the chip nearest to fixed holes on the board in the drop tests and simulations.

• Genomics & Informatics
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• v.3 no.4
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• pp.159-165
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• 2005

The Korean Twin Register (n=154,783 pairs) was reported in 2002 as the first nationwide twin study in Korea and the largest study in Asia. The Twin Register has the information of disease outcomes since 1990, and basic clinical and questionnaire data from biennial health examination provided by Korea National Health Service. The author attempted to calculate some of the genetic parameters of cancers in this population. Common cancers in Korea known to have familial aggregation (colon and breast) and cancers of which familial aggregation is unclear (stomach cancer) were examined for their familial recurrence risks. There were 699 stomach cancers, 438 breast and 491 colorectal cancers cases in the twin register between 1991 and 2003. Like-sex twins showed recurrence risks (${\lambda}_{LS}$) of 5.1 (95% CI 3.7-6.9) for stomach cancers, 15.5 (95% CI1 0.9-20.2) for female breast cancers, and 28.1 (95% CI 23.5-34.4) for colon cancers. Colorectal cancers of female like-sex twins show significantly higher familial recurrence risk 40.7 (95% CI 34.6-47.4), suggesting higher genetic contribution in women than in men. The results show increased familial risks compared with previous studies from the same register and are largely compatible with other studies. The data of the Twin Register could be used for estimating population level genetic parameters, as well as base of the various studies.

• Archives of Pharmacal Research
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• v.22 no.2
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• pp.130-136
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• 1999

Mouse guanylate-binding protein 3 (mGBP3) is a 71-kDa GTPase which belongs to GTP-binding protein family. The present study showed that the expression of mGBP3 transcript was readily induced in a dose dependent fashion in the macrophage cell line RAW264.7 treated with either $interferon-{\gamma} (IFN-\gamma)$ or lipopolysaccaride (LPS). The expression of mGBP3 protein was also apparent by 4 and 6 h after the treatment of cells with IFN-\gamma (100 U/ml) or LPS ($1{\mu}g/ml$) , and remained at palteau for at least 24 h. Cycloheximide ($10{\mu}g/ml$) had no effect on the $IFN-\gamma-$ or LPS-induced mGBP3 expression, suggesting that the mGBP3 induction did not require further protein synthesis. Interestingly, a protein kinase C (PKC) inhibitor staurosporine (50 nM) abolished the induction of mGBP3 expression by LPS, but not by $IFN-{\gamma}$. These findings suggest that mGBP3 may be involved in the macrophage activation process and both IFN-\gamma and LS induce the mGBP3 expression through distinct signal transduction pathways.

• Archives of Pharmacal Research
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• v.28 no.12
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• pp.1386-1391
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• 2005

This study examined the role of Kupffer cells in altering the hepatic secretory and microsomal function during ischemia and reperfusion (ls/Rp). Rats were subjected to 60 min of hepatic ischemia, followed by 1 and 5 h of reperfusion. Gadolinium chloride ($GdCl_{3}$, 7.5 mg/kg body weight, intravenously) was used to inactivate the Kupffer cells 1 day prior to ischemia. Is/Rp markedly increased the serum aminotransferase level and the extent of lipid peroxidation. $GdCl_{3}$ significantly attenuated these increases. Is/Rp markedly decreased the bile. flow and cholate output, and $GdCl_{3}$ restored their secretion. The cytochrome P450 content was decreased by Is/Rp. However, these decreases were not prevented by $GdCl_{3}$. The aminopyrine N-demethylase activity was decreased by Is/Rp, while the aniline p-hydroxylase activity was increased. $GdCl_{3}$ prevented the increase in the aniline p-hydroxylase activity. Overall, Is/Rp diminishes the hepatic secretory and microsomal drug-metabolizing functions, and Kupffer cells are involved in this hepatobiliary dysfunction.

• Structural Engineering and Mechanics
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• v.78 no.1
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• pp.23-30
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• 2021

In this paper, we established the generalized thermoelasticity phenomenon in an isotropic elastic medium considering the electromagnetic field, rotation and two-temperature. Three theories of generalized thermoelasticity have been applied: Lord-Shulman (one relaxation time), Green-Lindsay (two relaxation times), as well as the coupled theory. We discussed some particular cases in the context of the wave propagation phenomenon in thermoelasticity. From solving the fundamental equations, we arrived that there are three waves: P-, T- and SV-waves that we calculated their velocities. The boundary conditions for mechanical stress and Maxwell's stress and thermal insulated or isothermal have been applied to determine the amplitudes ratios (reflection coefficients) for P-, T - and SV waves. Some utilitarian aspects are obtained from the reflection coefficients, presented graphically, and the new conclusions have been presented. Comparisons are made for the results predicted by different theories (CT, LS, GL) in the absence and presence of the electro-magnetic field, rotation, as well as two-temperature on the reflection of generalized thermoelastic waves. The results obtained concluded that the external parameters as the angle of incidence, electromagnetic field, rotation as well as the theories parameters have strong effect on the phenomenon.