• Biomolecules & Therapeutics
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• 제27권4호
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• pp.404-413
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• 2019

Udenafil, which is a $PDE_5$ inhibitor, is used to treat erectile dysfunction. However, it is unclear whether udenafil induces hair growth via the stimulation of adipose-derived stem cells (ASCs). In this study, we investigated whether udenafil stimulates ASCs and whether increased growth factor secretion from ASCs to facilitate hair growth. We found that subcutaneous injection of udenafiltreated ASCs accelerated telogen-to-anagen transition in vivo. We also observed that udenafil induced proliferation, migration and tube formation of ASCs. It also increased the secretion of growth factors from ASCs, such as interleukin-4 (IL-4) and IL12B, and the phosphorylation of ERK1/2 and $NF{\kappa}B$. Furthermore, concomitant upregulation of IL-4 and IL12B mRNA levels was attenuated by ERK inhibitor or $NF{\kappa}B$ knockdown. Application of IL-4 or IL12B enhanced anagen induction in mice and increased hair follicle length in organ culture. The results indicated that udenafil stimulates ASC motility and increases paracrine growth factor, including cytokine signaling. Udenafil-stimulated secretion of cytokine from ASCs may promote hair growth via the ERK and $NF{\kappa}B$ pathways. Therefore, udenafil can be used as an ASC-preconditioning agent for hair growth.

• 방사성폐기물학회지
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• 제19권1호
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• pp.51-58
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• 2021

Chemical decontamination of primary systems in a nuclear power plant (NPP) prior to commencing the main decommissioning activities is required to reduce radiation exposure during its process. The entire process is repeated until the desired decontamination factor is obtained. To achieve improved decontamination factors over a shorter time with fewer cycles, the appropriate flow characteristics are required. In addition, to prepare an operating procedure that is adaptable to various conditions and situations, the transient analysis results would be required for operator action and system impact assessment. In this study, the flow characteristics in the steady-state and transient conditions for the chemical decontamination operations of the Kori-1 NPP were analyzed and compared via the MARS-KS code simulation. Loss of residual heat removal (RHR) and steam generator tube rupture (SGTR) simulations were conducted for the postulated abnormal events. Loss of RHR results showed the reactor coolant system (RCS) temperature increase, which can damage the reactor coolant pump (RCP)s by its cavitation. The SGTR results indicated a void formation in the RCS interior by the decrease in pressurizer (PZR) pressure, which can cause surface exposure and tripping of the RCPs unless proper actions are taken before the required pressure limit is achieved.

• Restorative Dentistry and Endodontics
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• 제48권2호
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• pp.20.1-20.13
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• 2023

This mini-review was conducted to present an overview of the use of exosomes in regenerating the dentin-pulp complex (DPC). The PubMed and Scopus databases were searched for relevant articles published between January 1, 2013 and January 1, 2023. The findings of basic in vitro studies indicated that exosomes enhance the proliferation and migration of mesenchymal cells, as human dental pulp stem cells, via mitogen-activated protein kinases and Wingless-Int signaling pathways. In addition, they possess proangiogenic potential and contribute to neovascularization and capillary tube formation by promoting endothelial cell proliferation and migration of human umbilical vein endothelial cells. Likewise, they regulate the migration and differentiation of Schwann cells, facilitate the conversion of M1 pro-inflammatory macrophages to M2 anti-inflammatory phenotypes, and mediate immune suppression as they promote regulatory T cell conversion. Basic in vivo studies have indicated that exosomes triggered the regeneration of dentin-pulp-like tissue, and exosomes isolated under odontogenic circumstances are particularly strong inducers of tissue regeneration and stem cell differentiation. Exosomes are a promising regenerative tool for DPC in cases of small pulp exposure or for whole-pulp tissue regeneration.

• 한국식품저장유통학회지
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• 제30권1호
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• pp.42-51
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• 2023

This study aimed to characterize a lytic Salmonella Typhimurium-specific (ST) phage and its biofilm control capability against S. Typhimurium biofilm on polypropylene surface. ST phage was isolated, propagated, and purified from water used in a slaughterhouse. The morphology of ST phage was observed via transmission electron microscopy. Its bactericidal effect was evaluated by determining bacterial concentrations after the phage treatment at various multiplicities of infection (MOIs) of 0.01, 1.0, and 100. Once the biofilm was formed on the polypropylene tube after incubation at 37℃ for 48 h, the phage was treated and its antibiofilm capability was determined using crystal violet staining and plate count method. The phage was isolated and purified at a final concentration of ~11 log PFU/mL. It was identified as a myophage with an icosahedral head (~104 nm) and contractile tail (~90-115 nm). ST phage could significantly decrease S. Typhimurium population by ~2.8 log CFU/mL at an MOI of 100. After incubation for 48 h, biofilm formation on polypropylene surface was confirmed with a bacterial population of ~6.9 log CFU/cm². After 1 h treatment with ST phage, the bacterial population in the biofilm was reduced by 2.8 log CFU/cm². Therefore, these results suggest that lytic ST phage as a promising biofilm control agent for eradicating S. Typhimurium biofilm formed on food contact surfaces.

• 한국재료학회지
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• 제34권3호
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• pp.138-143
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• 2024

Ni-CNT nanocomposites were synthesized via the electrical explosion of wire (EEW) in acetone and deionized (DI) water liquid conditions with different CNT compositions. The change in the shape and properties of the Ni-CNT nanopowders were determined based on the type of fluids and CNT compositions. In every case, the Ni nanopowder had a spherical shape and the CNT powder had a tube shape. However, the Ni-CNT nanopowders obtained in DI water exhibited irregular shapes due to the oxidation of Ni. Phase analysis also revealed the existence of nickel oxide when using DI water, as well as some unknown peaks with acetone, which may form due to the metastable phase of Ni. Magnetic properties were investigated using a Vibrating Sample Magnetometer (VSM) for all cases. Nanopowders prepared in DI water conditions had better magnetic properties than those in acetone, as evidenced by the simultaneous formation of super paramagnetic NiO peaks and ferromagnetic Ni peaks. The DI water (Ni:CNT = 1:0.3) sample revealed better magnetic results than the DI water (Ni-CNT = 1:0.5) because it had less CNT contents.

• 한국안전학회지
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• 제31권5호
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• pp.22-27
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• 2016

The Electrostatic Charge Prevention Technology is a core factor that highly influences the yield of Ultra High Resolution Flat Panel Display and high-integrated semiconductor manufacturing processes. The corona or x-ray ionizations are commonly used in order to eliminate static charges during manufacturing processes. To develop such a revolutionary x-ray ionizer that is free of x-ray radiation and has function to control the volume of ion formation simultaneously is a goal of this research and it absolutely overcomes the current risks of x-ray ionization. Under the International Commission on Radiological Protection, it must have a leakage radiation level that should be lower than a recommended level that is $1{\mu}Sv/hour$. In this research, the new generation of x-ray ionizer can easily control both the volume of ion formation and the leakage radiation level at the same time. In the research, the test constraints were set and the descriptions are as below; First, In order not to leak x-ray radiation while testing, the shielding box was fully installed around the test equipment area. Second, Implement the metallic Ring Electrode along a tube window and applied zero to ${\pm}8kV$ with respect to manage the positive and negative ions formation. Lastly, the ion duty ratio was able to be controlled in different test set-ups along with a free x-ray leakage through the metallic Ring Electrode. In the result of experiment, the maximum x-ray radiation leakage was $0.2{\mu}Sv/h$. These outcome is lower than the ICRP 103 recommended value, which is $1{\mu}Sv/h$. When applying voltage to the metallic ring electrode, the positive decay time was 2.18s at the distance of 300 mm and its slope was 0.272. In addition, the negative decay time was 2.1s at the distance of 300 mm and its slope was 0.262. At the distance of 200 mm, the positive decay time was 2.29s and its slope was 0.286. The negative decay time was 2.35s and its slope was 0.293. At the distance of 100 mm, the positive decay time was 2.71s and its slope was 0.338. The negative decay time was 3.07s and its slope was 0.383. According to these research, the observation was shown that these new concept of ionizer is able to minimize the leakage radiation level and to control the positive and negative ion duty ratio while ionization.

• Applied Science and Convergence Technology
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• 제26권5호
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• pp.118-128
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• 2017

The scope of this work is to determine and compare the effect of electron temperature ($T_e$) and number density ($N_e$) on the yield rate and concentration of reactive chemical species ($^{\bullet}OH$, $H_2O_2$ and $O_3$) in an argon, air and oxygen injected negative DC (0-4 kV) capillary discharge with water flow(0.1 L/min). The discharge was created between tungsten pin-to pin electrodes (${\Phi}=0.5mm$) separated by a variable distance (1-2 mm) in a quartz capillary tube (2 mm inner diameter, 4 mm outer diameter), with various gas injection rates (100-800 sccm). Optical emission spectroscopy (OES) of the hydrogen Balmer lines was carried out to investigate the line shapes and intensities as functions of the discharge parameters such as the type of gas, gas injection rate and inter electrode gap distances. The intensity ratio method was used to calculate $T_e$ and Stark broadening of Balmer ${\beta}$ lines was adopted to determine $N_e$. The effects of $T_e$ and $N_e$ on the reactive chemical species formation were evaluated and presented. The enhancement in yield rate of reactive chemical species was revealed at the higher electron temperature, higher gas injection rates, higher discharge power and larger inter-electrode gap. The discharge with oxygen injection was the most effective one for increasing the reactive chemical species concentration. The formation of reactive chemical species was shown more directly related to $T_e$ than $N_e$ in a flowing water gas injected negative DC capillary discharge.

• 생명과학회지
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• 제26권12호
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• pp.1367-1375
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• 2016

Cilostazol은 phosphodiesterase III의 선택적 저해제로 알려져 있으며, 뇌졸중 치료에 일반적으로 사용되고 있다. Cilostazol을 처리한 경우, 국소 뇌허혈이 발생한 후에 혈관신생을 통해서 혈관형성이 향상된다는 것을 본 연구자들이 발표하였다. 혈관신생은 조직의 허혈상태를 극복하기 위해서 혈관재생을 촉진하는 중요한 과정으로써, 혈관내피세포의 증식, 이동, 모세관구조 형성의 다단계 과정으로 구성되어 있다. 이에 본 연구에서는 인간 뇌혈관내피세포를 이용하여 cilostazol이 혈관신생의 각 단계들에 어떤 영향을 미치는지 조사하였다. Cilostazol은 농도의존적으로 뇌혈관내피세포의 이동성을 촉진하였으나, 뇌혈관내피세포의 증식과 모세관구조 형성에는 영향을 미치지 않았다. Cilostazol이 세포이동을 조절하는 기전을 분석하기 위해서 cDNA microarray를 수행하였고, 세포이동에 관련성이 있는 5종의 후보 유전자들을 선택하여 real-time PCR을 통해 해당 유전자의 발현을 검증하였다. Cilostazol에 의해서 발현양이 조절되는 유전자들로써, phosphoserine aminotransferase 1 (PSAT1)와 CCAAT/enhancer binding protein ${\beta}$ ($C/EBP{\beta}$)은 발현이 증가하였고, tissue factor pathway inhibitor 2 (TFPI2), retinoic acid receptor responder 1 (RARRES1), RARRES3는 발현이 감소하였다. 이상의 결과를 통해서 cilostazol이 혈관내피세포의 이동을 촉진하여 혈관신생을 향상시킬 수 있음을 제안할 수 있으며, 뇌혈관내피세포에 대한 cilostazol의 조절기전에 대해서 더욱 상세히 규명을 한다면 혈관형성을 통하여 허혈성 질환을 치료할 수 있는 유용한 정보가 될 것으로 기대한다.

• 한국동물학회지
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• 제27권1호
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• pp.13-24
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• 1984

산개구리의 germ plasm 및 축결정 세포질에 미치는 자외선의 영향을 수량적, 시간적으로 조사하였다. 산개구리 난의 식물극을 수정 후 60분경에 1,600 $ergs/mm^2$이상의 자외선을 조사하였을때 40%이상의 시원생식세포의 수가 감소하였으나, 그 이하의 양에서는 전혀 영향이 없었다. 그러나 1,600 $ergs/mm^2$부터는 시원생식세포 수의 감소 정도는 자외선의 양에 비례하였다. 또 신경관 형성에 전혀 영향을 미치지 않으면서 시원생식세포의 형성을 완전히 억제시키는 자외선의 양은 4,800 $ergs/mm^2$이었다. 이에 4,800 $ergs/mm^2$의 자외선을 수정 후 일정한 시간간격으로 조사하여 germ plasm에 미치는 자외선의 영향을 조사하였다. 그 결과 자외선이 조사된 시기가 이를수록 시원생식세포수의 감소가 크며, 수정후 60분부터 차츰 감소율이 줄어 들다가 3분열 이후에는 자외선의 효과가 거의 없음을 관찰하였다. 또한 시원생식세포와 축형성에 미치는 자외선의 영향을 시기적으로 비교한 결과 산개구리난의 축결정이 다른 무미양서류에서와 같이 수정에서 제1분열 사이의 $0.7\\sim0.8$시기 이전에 이루어지므로 그 이후에는 자외선의 감응도가 급격히 저하되었다. 그러나 germ plasm의 자외선에 대한 감응도는 훨씬 늦게까지 지속되어 8구기에 이르기까지 그 영향이 나타났다.

• 에너지공학
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• 제20권3호
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• pp.191-199
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• 2011

본 연구에서는 Drop Tube Furnace(DTF)를 이용한 $O_2/N_2$, $O_2/CO_2$ 조건에서 산소 농도(12, 21, 31%)에 따른 아역청탄 입자의 연소특성 및 질소산화물 배출특성에 관한 실험과 수치해석을 수행하였다. $O_2/N_2$, $O_2/CO_2$ 조건에서 산소 농도가 증가함에 따라 촤 연소율이 증가하였고 $O_2/CO_2$ 조건하에서 이산화탄소 경계층에서 석탄입자 표면으로의 산소 확산계수가 낮아지기 때문에 촤 연소율이 감소하였다. 산소 농도가 증가함에 따라 배출되는 NO의 농도는 증가하지만 완전 연소 조건인 31%의 산소 농도에서는 오히려 NO의 농도가 감소하였다. 반면, NO 배출 지수는 산소가 증가함에 따라 점차 감소하였다. $O_2/CO_2$ 조건에서 NO의 농도는 Thermal NO의 결여로 인해 $O_2/N_2$ 조건보다 작게 나타났다.