• 한국연소학회:학술대회논문집
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• 한국연소학회 제26회 KOSCO SYMPOSIUM 논문집
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• pp.13-19
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• 2003

As the environmental pollution becomes serious global problem, the regulation of emission exhausted from automobiles is strengthen. Therefore, it is very important to know how to reduce the NOx and PM simultaneously in diesel engines, which has lot of merits such as high thermal efficiency, low fuel consumption and durability. By this reason, the new concept called as Homogeneous Charge Compression Ignition(HCCI) engines are spotlighted because this concept reduced NOx and P.M. simultaneously. However, it is well known that HCCI engines increased HC and CO. Thus, the investigation of combustion characteristics which consists cool and hot flames for HCCI engines were needed to obtain the optimal combustion condition. In this study, combustion characteristics for direct inject type HCCI engine such as quantity of cool flame and hot flame, ignition timing and ignition delay were investigated to clarify the effects of these parameters on performance. The results revealed that diesel combustion showed the two-stage ignition of cool flame and hot flame, the rate of cool flame increase and hot flame decrease with increasing intake air temperature. On the other hand, the gasoline combustion is the single-stage ignition and ignition timing is near the TDC. In addition mixed fuel combustion showed different phenomenon, which depends on the ratio of gasoline component. Ignition timing of mixed fuel is retarded near the TDC and the ignition delay is increased according to ratio of gasoline.

• Journal of Microbiology
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• 제40권4호
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• pp.305-312
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• 2002

The effects of two natural polyamines (putrescine and spermidine) on the synthesis of ArcA, a response regulator of the Arc two-component signal transduction system, were studied using an E. coli mutant deficient in polyamine biosynthesis. Endogenous polyamine deficiency of the mutant resulted in marked reduction in the ArcA level determined by Western blot analysis. Putrescine supplement to the growth medium effectively increased the ArcA level of the mutant in a concentration-dependent manner. Spermidine also stimulated the ArcA level in the mutant to a greater degree than putrescine. Expression of arcA'::lacZ operon fusion in the mutant was stimulated 6-fold and 10-fold by putrescine and spermidine at a 1mM concentration, respectively, indicating that the stimulatory effect of the polyamines on ArcA synthesis is due to transcriptional induction, and that spermidine is a more potent arcA inducer than putrescine. The polyamine-dependent arcA'::lacZ induction was growth-phase-dependent and independent of either arcA or fnr which are two regulators involved in anaerobic stimulation of the Arch level. These results suggested that putrescine and spermidine polyamines may be potential intracellular signal molecules in the control of arcA expression, and thereby may play an important role in cellular metabolism.

• 한국자동차공학회논문집
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• 제12권1호
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• pp.17-24
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• 2004

As the environmental pollution becomes serious global problem, the regulation of emission exhausted from automobiles is strengthened. Therefore, it is very important to know how to reduce the NOx and PM simultaneously in diesel engines, which has lot of merits such as high thermal efficiency, low fuel consumption and durability. By this reason, the new concept called as Homogeneous Charge Compression Ignition(HCCI) engines are spotlighted because this concept reduced NOx and P.M. simultaneously. However, it is well known that HCCI engines increased HC and CO. Thus, the investigation of combustion characteristics which consists cool and hot flames for HCCI engines were needed to obtain the optimal combustion condition. In this study, combustion characteristics for direct injection type HCCI engine such as quantity of cool flame and hot flame, ignition timing and ignition delay were investigated to clarify the effects of these parameters on performance. The results revealed that diesel combustion showed the two-stage ignition of cool flame and hot flame, the rate of cool flame increase and hot flame decrease with increasing intake air temperature. On the other hand, the gasoline combustion is the single-stage ignition and ignition timing is near the TDC. In addition mixed fuel combustion showed different phenomenon, which depends on the ratio of gasoline component. Ignition timing of mixed fuel is retarded near the TDC and the ignition delay is increased according to ratio of gasoline.

• Toxicological Research
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• 제8권2호
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• pp.343-357
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• 1992

Tumor necrosis factor-${\alpha}$(TNF), a polypeptide hormone secreted primarily by activated macrophages, was originally identified on the basis of its ability to cause hemorrhagic necrosis and tumor regression in vivo. Subsequently, TNF has been shown to be an important component of the host responses to infection and cancer and may mediate the wasting syndrome known as cachexia. These systemic actions of TNF are reflected in its diverse effects on target cells in vitro. TNF initiates its diverse cellular actions by binding to specific cell surface receptors. Although TNF receptors have been identified on most of animal cells, regulation of these receptors and the mechanisms which transduce TNF receptor binding into cellular responses are not well understood. Therefore, in the present study, the mechanisms how TNF receptors are being regulated and how TNF receptor binding is being transduced into cellular responses were investigated in rat liver plasma membranes (PM) and ME-180 human cervical carcinoma cell lines. $^{125}I$-TNF bound to high ($K_d=1.51{\pm}0.35nM$)affinity receptors in rat liver PM. Solubilization of PM with 1% Triton X-100 increased both high affinity (from $0.33{\pm}0.04\;to\;1.67{\pm}0.05$ pmoles/mg protein) and low affinity (from $1.92{\pm}0.16\;to\;7.57{\pm}0.50$ pmoles/mg protein) TNF binding without affecting the affinities for TNF, suggesting the presence of a large latent pool of TNF receptors. Affinity labeling of receptors whether from PM or solubilized PM resulted in cross-linking of $^{125}I$-TNF into $M_r$ 130 kDa, 90 kDa and 66kDa complexes. Thus, the properties of the latent TNF receptors were similar to those initially accessible to TNF. To determine if exposure of latent receptors is regulated by TNF, $^{125}I$-TNF binding to control and TNF-pretreated membranes were assayed. Specific binding was increased by pretreatment with TNF (P<0.05), demonstrating that hepatic PM contains latent TNF receptors whose exposure is promoted by TNF. Homologous up-regulation of TNF receptors may, in part, be responsible for sustained hepatic responsiveness during chronic exposure to TNF. As a next step, the post-receptor events induced by TNF were examined. Although the signal transduction pathways for TNF have not been delineated clearly, the actions of many other hormones are mediated by the reversible phosphorylation of specific enzymes or target proteins. The present study demonstrated that TNF induces phosphorylation of 28 kDa protein (p28). Two dimensional soidum dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE) resolved the 28kDa phosphoprotein into two isoforms having pIs of 6.2 and 6.1. The pIs and relative molecular weight of p28 were consistent with those of a previously characterized mRNA cap binding protein. mRNA cap binding proteins are a class of translation initiation factors that recognize the 7-methylguanosine cap structure found on the 5' end of eukaryotic mRNAs. In vitro, these proteins are defined by their specific elution from affinity columns composed of 7-methylguanosine 5'-triphosphate($m^7$GTP)-Sepharose. Affinity purification of mRNA cap binding proteins from control and TNF treated ME-180 cells proved that TNF rapidly stimulates phosphorylation of an mRNA cap binding protein. Phosphorylation occurred in several cell types that are important in vitro models of TNF action. The mRNA cap binding protein phosphorylated in response to TNF treatment was purifice, sequenced, and identified as the proto-oncogene product eukaryotic initiation factor-4E(eIF-4E). These data show that phosphorylation of a key component of the cellular translational machinery is a common early event in the diverse cellular actions of TNF.

• 동의신경정신과학회지
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• 제21권4호
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• pp.21-39
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• 2010

Objectives : This study was to investigate the characteristics of the heart rate variability(HRV), types of insomnia and accompanying symptoms of 175 insomnia patients. Methods : For this study we carried out HRV, Inbody of 175 patients with insomnia who have come to Dongeui oriental hospital of Dongeui university from the period of Janaury 2008 to September 2010. We studied the association of the insomnia patients' age and gender with HRV, accompanying symptoms and the types of insomnia. The information of the accompanying symptoms and types of insomnia was based on each patients' progress note. Results : l. There was no significant differences in the characteristics of HRV between male and female. 2. The most frequent symptom shown among the insmonia patents' was headache(41.14%). 3. Comparing the symptoms between the gender, female patients had more dry mouth, alternative periodic chill and fever, and hot flush symptoms than the male patients. 4. Comparing the symptoms between the age groups(divided in two), the lower age group (20~59) had more dizziness and constipation symptoms than the higher age group (over 60). 5. Comparing the types of insomma between the age group, the higher age group (over 60) had more termination insomnia. 6. The types of insomnia of the entire insomnia patients were onset insomnia (73.1%), maintenance insomnia(20.6%), termination insomma(l7.1 %), shallow sleep (52.6%), listed by order of frequency. 7. The patients who takes hypnotics had more anorexia symptoms than the patients who doesn't take hypnotics. 8. There was no visible differences of the average fractal portrait between male and female. The age group of 20~30yrs. had the highest average fractal portrait, and the age group of 30~59yrs. the second highest, and the age group over 60yrs. the lowest. 9. The average of the regulation reserves of the autonomic nervous system(B2) - was lower than the regulation level of the ANS at the present (Bl). 10. When compared the priority of the function of the ANS, it showed that the proportion of HF($38.61{\pm}29.19%$)was the most, and than VLF($30.65{\pm}23.36%$), LF($20.04{\pm}19.13%$) the least. 11. The average of the compensation level of the central nervous system at present(Cl) - was lower than the compensation reserves of the CNS(C2). 12. The average of the control reserves of the cerebrum(D2) - was lower than the control level of the cerebrum at the present (Dl). 13. There was no visible differences between different sexes and ages in pulse rate. 14. The abdomen fat ratio above the line of the insomnia patients was 77.97% in male and 93.1% in female. Both sexes showed that insomnia patients had more abdomen fat that the standard, and female patients had more abd. fat than male patients. Conclusions : This study shows that the HRV of insomnia patients had no significant differences between gender. Fractal portrait, HF, LF and VLF of the insomnia patients are in inverse proportion to the age. The study of the Body Component Analysis showed that female had more abdomen fat than male, and both gender showed more abdomen fat than the standard. When looked into the accompanying symptoms of the insomnia patients, the symptoms show differences according to gender, age and hypnotics taking, as shown as below. In the entire patients, Headache was the most accompanying symptom. Female had more dry mouth, alternative periodic chill and fever, and hot flush symptoms than male. Higher age groups had more dizziness and constipation as accompanying symptoms than lower age groups. Patients who takes hypnotics had more anorexia than those who dont.

• Molecules and Cells
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• 제23권1호
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• pp.108-114
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• 2007

The mitogen-activated protein kinase (MAPK) signaling cascade is critical for regulating plant defense systems against various kinds of pathogen and environmental stresses. One component of this cascade, the MAP kinase kinases (MAPKK), has not yet been shown to be induced in plants following biotic attacks, such as those by insects and fungi. We describe here a gene coding for a blast (Magnaporthe grisea)- and insect (Nilaparvata lugens)-responsive putative MAPK kinase, OmMKK1 (Oryza minuta MAPKK 1), which was identified in a library of O. minuta expressed sequence tags (ESTs). Two copies of OmMKK1 are present in the O. minuta genome. They encode a predicted protein with molecular mass 39 kDa and pI of 6.2. Transcript patterns following imbibition of plant hormones such as methyl jasmonic acid (MeJA), ethephone, salicylic acid (SA) and abscisic acid (ABA), as well as exposure to methyl viologen (MV), revealed that the expression of OmMKK1 is related to defense response signaling pathways. A comparative analysis of OmMKK1 and its O. sativa ortholog OsMKK1 showed that both were induced by stress-related hormones and biotic stresses, but that the kinetics of their responses differed despite their high amino acid sequence identity (96%).

• 한국환경보건학회지
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• 제41권1호
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• pp.49-60
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• 2015

Objectives: Pine needles were used as a passive air sampler (PAS) of atmospheric persistent organic pollutants (POPs). This study was performed to investigate concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) deposited on pine needles near a waste incinerator and PCDD/Fs source contributions using principal component analysis (PCA). Methods: Two-year-old pine needles were sampled at 11 points with respect to distance and wind direction from the incinerator. PCDD/Fs deposited on pine needles were analyzed with HRGC/HRMS. The source contribution of PCA was calculated with SPSS. Results: The average concentration of PCDD/Fs deposited on pine needle was 0.79 (0.27-1.76) pg TEQ/g dry, PCDDs with 0.24 (0.01-0.95) pg TEQ/g dry and PCDFs with 0.56 (0.27-0.82) pg TEQ/g dry, respectively. The average concentration fraction of PCDDs was 29.7%, that of PCDFs was 70.3%, and PCDFs were more prevalent than PCDDs. The contributions of PCDD/Fs sources were estimated as incineration at 58.3% and automobiles at 28.4%. However, a relation and regulation between PCDD/Fs concentrations deposited on pine needles and distance from incinerator or wind direction was not shown. Conclusion: It was concluded that atmospheric PCDD/Fs concentrations near an industrial complex with a waste incinerator were affected by multiple sources. However, PCDD/Fs concentrations were lower than in other inland cities with the exception of background area.

• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2003년도 학술발표대회 발표논문초록집
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• pp.96-96
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• 2003

Nek2 (NIMA-related protein) is a mammalian cell cycle-regulated kinase that involves in chromosome condensation and centrosome regulation and NuMA (nuclear mitotic apparatus protein) is involved in spindle assembly during a cell cycle. The cellular distribution and organization of the centrosomal components is completely unknown during fertilization and embryonic development. We examined distribution of two well-known centrosomal proteins, Nek2 and NuMA in mouse gametes and embryos to get an insight in the reorganization of centrosomal proteins during germ cell development and early fertilization. Spermatogenic cells, gametes, and embryos were analyzed with anti-Nek2 or -NuMA antibodies by immunological assay, RT-PCR, and overexpression through gene transfection. Mitotically or meiotically active spermatogenic cells were intensively stained with these antibodies in both centrosomes and cytoplasm, whereas the oocytes showed different staining patterns depending on the meiotic stages. During maturation, GV, GVBD, and MI stage were clearly stained with NuMA antibody in the nucleus or cytoplasm at MII. Also, Nek2 was detectable in cytoplasm as scattered spots or chromosome associated at MII. In early developmental embryo, NuMA was detected in nucleus of each blastomere, while Nek2 was detected in cytoplasm. In contrast to previously reported results, Nek2 and NuMA were detected in both decondensing head, and the centriole of demembranated and decondensed sperm or whole body of trypsin-treated sperm for Nek2. During meiotic progress in oocytes, transcripts levels were the highest in MI stage and then downregulated in MII. Also, it shows dramatically change in early developmental embryos, firstly, it was increased until 4 cell stage and reduced in 8 cell stage, and finally, transcript levels were upregulated until blastoscyst. This finding suggests that cnetrosomal component may play an important role in reorganizing of functional centrosome during fertilization process and subsequent development.

• Safety and Health at Work
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• 제10권4호
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• pp.518-526
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• 2019

Background: Additive manufacturing (AM) is a rapidly expanding new technology involving challenges to occupational health. Here, metal exposure in an AM facility with large-scale metallic component production was investigated during two consecutive years with preventive actions in between. Methods: Gravimetric analyzes measured airborne particle concentrations, and filters were analyzed for metal content. In addition, concentrations of airborne particles <300 nm were investigated. Particles from recycled powder were characterized. Biomonitoring of urine and dermal contamination among AM operators, office personnel, and welders was performed. Results: Total and inhalable dust levels were almost all below occupational exposure limits, but inductively coupled plasma mass spectrometry showed that AM operators had a significant increase in cobalt exposure compared with welders. Airborne particle concentrations (<300 nm) showed transient peaks in the AM facility but were lower than those of the welding facility. Particle characterization of recycled powder showed fragmentation and condensates enriched in volatile metals. Biomonitoring showed a nonsignificant increase in the level of metals in urine in AM operators. Dermal cobalt and a trend for increasing urine metals during Workweek Year 1, but not in Year 2, indicated reduced exposure after preventive actions. Conclusion: Gravimetric analyses showed low total and inhalable dust exposure in AM operators. However, transient emission of smaller particles constitutes exposure risks. Preventive actions implemented by the company reduced the workers' metal exposure despite unchanged emissions of particles, indicating a need for careful design and regulation of the AM environments. It also emphasizes the need for relevant exposure markers and biomonitoring of health risks.

• Asian-Australasian Journal of Animal Sciences
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• 제28권6호
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• pp.788-795
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• 2015

Two dimensional-fluorescence difference gel electrophoresis (2D DIGE) is an emerging technique for comparative proteomics, which improves the reproducibility and reliability of differential protein expression analysis between samples. The purpose of this study was to investigate bovine pregnancy-specific proteins in the proteome between bovine pregnant and non-pregnant serum using DIGE technique. Serums of 2 pregnant Holstein dairy cattle at day 21 after artificial insemination and those of 2 non-pregnant were used in this study. The pre-electrophoretic labeling of pregnant and non-pregnant serum proteins were mixed with Cy3 and Cy5 fluorescent dyes, respectively, and an internal standard was labeled with Cy2. Labeled proteins with Cy2, Cy3, and Cy5 were separated together in a single gel, and then were detected by fluorescence image analyzer. The 2D DIGE method using fluorescence CyDye DIGE flour had higher sensitivity than conventional 2D gel electrophoresis, and showed reproducible results. Approximately 1,500 protein spots were detected by 2D DIGE. Several proteins showed a more than 1.5-fold up and down regulation between non-pregnant and pregnant serum proteins. The differentially expressed proteins were identified by MALDI-TOF mass spectrometer. A total 16 protein spots were detected to regulate differentially in the pregnant serum, among which 7 spots were up-regulated proteins such as conglutinin precursor, modified bovine fibrinogen and IgG1, and 6 spots were down-regulated proteins such as hemoglobin, complement component 3, bovine fibrinogen and IgG2a three spots were not identified. The identified proteins demonstrate that early pregnant bovine serum may have several pregnancy-specific proteins, and these could be a valuable information for the development of pregnancy-diagnostic markers in early pregnancy bovine serum.