• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.9
• /
• pp.4137-4142
• /
• 2015

The zinc finger transcription factor EGR 1 has a role in controlling synaptic plasticity, wound repair, female reproductive capacity, inflammation, growth control, apoptosis and tumor progression. Recent studies mainly focused on its role in growth control and apoptosis, however, little is known about its role in epithelial-mesenchymal transition (EMT). Here, we aim to explore whether EGR 1 is involved in TGF-${\beta}1$-induced EMT in non-smallcell lung cancer cells. Transforming growth factor (TGF)-${\beta}1$ was utilized to induce EMT in this study. Western blotting, RT-PCR, and transwell chambers were used to identify phenotype changes. Western blotting was also used to observe changes of the expression of EGR 1. The lentivirus-mediated EGR 1 vector was used to increase EGR 1 expression. We investigated the change of migration to evaluate the effect of EGR 1 on non-small-cell lung cancer cells migration by transwell chambers. After stimulating with TGF-${\beta}1$, almost all A549 cells and Luca 1 cells (Non-small-cell lung cancer primary cells) changed to mesenchymal phenotype and acquired more migration capabilities. These cells also had lower EGR 1 protein expression. Overexpression of EGR 1 gene with EGR 1 vector could decrease tumor cell migration capabilities significantly after adding TGF-${\beta}1$. These data s howed an important role of EGR 1 in the EMT of non-small-cell lung cancer cells, as well as migration.

• IMMUNE NETWORK
• /
• v.15 no.3
• /
• pp.161-166
• /
• 2015

Early growth response (Egr)-1 is a $Cys_2-His_2-type$ zincfinger transcription factor. It has been shown to induce survival and proliferation of immature and mature B cells, respectively, but its role in the differentiation of B cells into plasma cells remains unclear. To examine the effects of Egr-1 deficiency on the activation of B cells, naive B cells from $Egr1^{-/-}$mice and their wild-type (WT) littermates were activated to proliferate and differentiate, and then assayed by FACS. Proportions of cells undergoing proliferation and apoptosis did not differ between $Egr1^{-/-}$ and WT mice. However, $Egr1^{-/-}$ B cells gave rise to fewer plasma cells than WT B cells. Consistently, $Egr1^{-/-}$ mice produced significantly lower titer of antigen-specific IgG than their WT littermates upon immunization. Our results demonstrate that Egr-1 participates in the differentiation program of B cells into plasma cells, while it is dispensable for the proliferation and survival of mature B cells.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.16 no.1
• /
• pp.127-133
• /
• 2008

Since the 1960's, exhaust gas recirculation(EGR) has been used effectively in spark ignition(SI) engines to control the exhaust emissions of the oxides of nitrogen(NOx). The most important requirements for the application of EGR systems to conventional SI engines are controllable flow rate and good dynamic response. In order to evaluate the characteristics of the electronic EGR valve, a test bench which is consisted of blower, heater, air flow meter and driving unit for electronic EGR valve was set up to simulate engine operating conditions. During the tests, the valve actuation parameters were controlled and the valve lifts and flow rates were measured to infer the characteristics of EGR valve. The results confirmed the capabilities of mathematical analysis and it seems that the correction for the valve lift and potentiometer output is necessary to achieve precise control of EGR rates.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.25 no.1
• /
• pp.42-50
• /
• 2017

A study has been conducted to develop an aluminum EGR cooler for the LPL EGR system of a diesel engine. Aluminum has a much lower density and thermal conductivity that is about 12 times or more than that of stainless steel, so it is advantageous for use in an EGR cooler for weight reduction and cooling performance effects. A design process has been carried out to ensure heat dissipation performance in a restricted space to investigate the geometric parameters and satisfy the requirements for pressure drops at both fluid sides. The tubes of exhaust gas have been designed as extruded tubes. An aluminum EGR cooler consisting of extruded tubes entails a simpler manufacturing process compared to a stainless steel EGR cooler with conventional heat transfer fins. A prototype has been manufactured from the final model selected through the design process. The performance of the aluminum EGR cooler was evaluated and compared with that of the conventional one. The weight of the aluminum EGR cooler is reduced by 22.9%, while performance is significantly improved.

• BMB Reports
• /
• v.46 no.2
• /
• pp.92-96
• /
• 2013

The breast cancer susceptibility gene BRCA1 encodes a nuclear protein, which functions as a tumor suppressor and is involved in gene transcription and DNA repair processes. Many families with inherited breast and ovarian cancers have mutations in the BRCA1 gene. However, only a few studies have reported on the mechanism underlying the regulation of BRCA1 expression in humans. In this study, we investigated the transcriptional regulation of BRCA1 in HeLa cells treated with etoposide. We found that three Egr-1-binding sequences (EBSs) were located at -1031, -1005, and -385 within the enhancer region of the BRCA1 gene. Forced expression of Egr-1 stimulated the BRCA1 promoter activity. EMSA data showed that Egr-1 bound directly to the EBS within the BRCA1 gene. Knockdown of Egr-1 through the expression of a small hairpin RNA (shRNA) attenuated etoposide-induced BRCA1 promoter activity. We conclude that Egr-1 targets the BRCA1 gene in HeLa cells exposed to etoposide.

• Journal of the Korean Institute of Gas
• /
• v.24 no.6
• /
• pp.1-10
• /
• 2020

Reactivity controlled compression ignition (RCCI) combustion is one of dual-fuel combustion systems which can be constructed by early diesel injection during the compression stroke to improve premixing between diesel and air. As a result, RCCI combustion promises low nitrogen oxides (NOx) and smoke emissions comparing to those of general dual-fuel combustion. For this combustion system, to meet the intensified emission regulations without emission after-treatment systems, exhaust gas recirculation (EGR) is necessary to reduce combustion temperature with lean premixed mixture condition. However, since EGR is supplied from the front of turbocharger system, intake pressure and the amount of fresh air supplementation are decreased as increasing EGR rate. For this reason, the effect of various EGR rates on the brake power and thermal efficiency of natural gas/diesel RCCI combustion under two different operating conditions in a 6 L compression ignition engine. Varying EGR rate would influence on the combustion characteristic and boosting condition simultaneously. For the 1,200/29 kW and 1,800 rpm/(lower than) 90 kW conditions, NOx and smoke emissions were controlled lower than the emission regulation of 'Tier-4 final' and the maximum in-cylinder pressure was 160 bar for the indurance of engine system. The results showed that under 1,200 rpm/29 kW condition, there were no changes in brake power and thermal efficiency. On the other hand, under 1,800 rpm condition, brake power and thermal efficieny were decreased from 90 to 65 kW and from 37 to 33 % respectively, because of deceasing intake pressure (from 2.3 to 1.8 bar). Therefore, it is better to supply EGR from the rear of compressor, i.e. low pressure EGR (LP-EGR) system, comparing to high pressure EGR (HP-EGR) for the improvement of RCCI power and thermal efficiency.

• Journal of the KSME
• /
• v.20 no.1
• /
• pp.21-30
• /
• 1980

기관의 흡기에 배기의 일부를 혼입하는 배기재순환 (Exhaust Gas Recirculation, 약해서 EGR)은 배기중의 NOx 농도를 저하시키는 효과가 있기 때문에 자동차용 기관의 배기정화를 위한 유효한 수단의 하나로 생각된다. 배기가스의 공해성분인 CO, HC NOx 중에서 CO, HC는 실용적인 처 리방법이 각각 여러종류 개발되어 있지만 NOx를 기관으로부터 배출한 후의 단계에서 처리하는 실용적인 방법은 매우 어렵다, 따라서 이와 같은 단계에 있어서는 EGR를 유효하게 이용하는 것이 NOx 저감대책의 지름길이라 할 수 있다. 그러나 EGR를 시행하는 경우, 신기의 흡입량은 EGR에 의하여 제한을 받아 감소하므로 신기의 감소분만큼 출력이 저하하는 것을 막을 도리는 없다. 따라서 장래 대부분의 자동차용기관이 EGR시스템을 정착하게 되면 동력성능을 저하시 키지 않기 위하여 EGR에 상당하는 실린더용적의 증가를 하거나, 어떠한 대책이 필요할 것이다. 그러므로 저자는 장래 EGR시스템을 장착하게될 경우를 고려하는 기관에 EGR을 시해하는 경우, 기관사이클, 연소 및 배기성분 운전 Paramater와 EGR의 관계등에 대하여 기술하고저 한다.

• Journal of Life Science
• /
• v.23 no.8
• /
• pp.970-977
• /
• 2013

The epithelial-to-mesenchymal transition (EMT) plays an essential role in embryogenesis and is involved in tumor metastasis and invasion; it significantly contributes to tumor progression and aggressiveness. The EMT is characterized by a loss of epithelial cell polarity as a result of the reduced expression of epithelial E-cadherin, a hallmark of the EMT, and the acquisition of mesenchymal-like cell morphology. Reactive oxygen species (ROS) such as $O_2{^-}$, $H_2O_2$, and $OH^-$ have been demonstrated to induce the EMT; although Snail is involved in ROS-induced EMT by transcriptionally repressing E-cadherin, its mechanism is not fully understood. In this study, we examined the effects of early growth response 1 (Egr-1) overexpression in noninvasive breast tumor cell line MCF-7 cells. Upon Egr-1 overexpression, MCF-7 cells lost epithelial cell polarity and became more spindle-shaped, indicating that Egr-1 may induce EMT. We found that Snail is implicated in Egr-1 induced EMT. We further demonstrate that the Egr-1-Snail axis is activated by ROS and plays a critical role(s) in ROS-induced EMT.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.19 no.1
• /
• pp.101-108
• /
• 2011

Understanding the exhaust gas recirculation (EGR) cooler fouling in diesel engine is important factor in the durability characteristic of a EGR system. We develope a test rig and PM feeder using carbon black to examine the effect of fouling on EGR cooler devices those were consisted of flat and shell & tube type. The EGR cooler fouling process is a complex interaction involving heat exchanger shape, boundary condition, constitutes, chemistry and operating mode. As the soot deposited to EGR cooler, these formed a thin deposit layer that was less heat exchange than the fresh status of tube enclosing the exhaust gas, resulting in lower heat exchange effectiveness in both type coolers. But these deposits caused different results in pressure drop, it is increased in flat type, but decreased in Shell & tube type of EGR cooler. A cause was estimated from a change of the flow structure and a decrease of contact area as the EGR cooler fouling.

• Journal of Energy Engineering
• /
• v.25 no.1
• /
• pp.100-107
• /
• 2016

In this study confirmed the reduction effect of pollutant by applying Fi-EGR and FPI-EGR to hybrid combustion system realizing premixed flame and non-premxied flame at once. The results showed that NOx emission index decreased significantly in case of adopting EGR. Additionally, the hybrid combustion system with EGR resulted in a better performance compared to usual non-premixed combustion system such that it can reduce $NO_x$ emission at equivalent EGR ratios. Especially, in the case of 25% of FI-EGR ratio at hybrid combustion system that the ratio of non-premixed and premixed is 50 : 50, NOx emission index reduction rate was about 59% compared to $NO_x$ emission of non-premixed combustion system without EGR and in the case of 15% of FPI-EGR ratio at hybrid combustion system that the ratio of non-premixed and premixed is 70 : 30, $NO_x$ emission index reduction rate was about 48% compared to $NO_x$ emission of hybrid combustion system without EGR.