Influence of Al2O3 Content and Cooling Rate on Crystallization in Fe2O3–CaO–SiO2–Al2O3 Systems

Tae Jun Park,Joon Sung Choi,Dong Joon Min 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.9

The behavior of silico-ferrite of calcium and aluminum (SFCA) phases and the influence of sintered ore quality were investigatedusing a confocal laser scanning microscope to understand how the Al2O3content of iron ore affects the sintered orestructure and the crystallization behavior of SFCA in a Fe2O3–CaO–Al2O3–SiO2 pseudo-quaternary system. The experimentalresults were used to inform simulations of the heterogeneous dynamic behavior in response to the rapid temperature changesand various chemical compositions typically encountered in actual sintering processes. Increasing the Al2O3content in theFe2O3–CaO–Al2O3–SiO2 pseudo-quaternary system led to the hematite content decreasing, which affects the reducibilityof the sintered ore. The correlation between the creation of SFCA and the cooling effect associated with varying the Al2O3is discussed in detail.

Elevated TRAF2/6 expression in Parkinson's disease is caused by the loss of Parkin E3 ligase activity.

Chung, Ji-Yun,Park, Hee Ra,Lee, Su-Jin,Lee, Sun-Hye,Kim, Jin Sik,Jung, Youn-Sang,Hwang, Sang Hyun,Ha, Nam-Chul,Seol, Won-Gi,Lee, Jaewon,Park, Bum-Joon United States and Canadian Academy of Pathology [e 2013 Laboratory investigation Vol.93 No.6

<P>Parkinson's disease (PD) is the second leading neurodegenerative disease, and is known to be induced by environmental factors or genetic mutations. Among the verified genetic mutations of PD, Parkin, isolated from the PARK2 locus, shows an autosomal recessive inheritance pattern and is known to be an E3 ligase. However, the physiological target of Parkin and the molecular mechanism of Parkin-deficiency-induced PD have not been clearly demonstrated until now. It has recently been proposed that inflammation, suggesting as a causal factor for PD, is enhanced by Parkin deficiency. Thus, we examined the relationship between inflammation-related factors and Parkin. Here, we provide the evidence that Parkin suppresses inflammation and cytokine-induced cell death by promoting the proteasomal degradation of TRAF2/6 (TNF-α receptor-associated factor 2/6). Overexpression of Parkin can reduce the half-lives of TRAF2 and TRAF6, whereas si-Parkin can extend them. However, mutant Parkins did not alter the expression of TRAF2/6. Thus, loss of Parkin enhances sensitivity to TNF-α- or IL-1β-induced JNK activation and NF-κB activation. Indeed, si-Parkin-induced apoptosis is suppressed by the knockdown of TRAF6 or TRAF2. We also observed elevated expression levels of TRAF6 and a reduction of IκB in an 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced PD mouse model. Moreover, elevated expression levels or aggregation of TRAF6 were detected in approximately half of the human PD tissues (7/15 cases) and 2 cases, respectively. In addition, TRAF6 and Parkin expression levels show a reverse relationship in human PD tissues. Our results strongly suggest that the reduction of Parkin or overexpression of TRAF2/6 by chronic inflammation would be the reason for occurrence of PD.</P>

LNT를 통해 분석한 국립공원 탐방목적과 산행 윤리 의식의 상관성 : 내장산국립공원 백양사지구와 남창지구를 중심으로

최형철(Choi Hyung Chul),박재철(Park Jae Chul),노재현(Roh Jae Hyun),신상섭(Shin Sang Sup),허준(Huh Joon) 한국산림휴양학회 2010 한국산림휴양학회지 Vol.14 No.3

본 연구는 LNT 항목의 분석을 통해서 산행 목적과 산행윤리의식 사이의 차이를 규명하기 위하여 수행되었다. 이를 위해서, 내장산국립공원의 백양사지구와 남창지구를 사례로 연구를 수행하였다. 이를 통해 국립공원 방문목적에 따라서 윤리 의식이 유의한 차이가 있음을 확인할 수 있었다. 다시 말하면, 산행목적의 탐방객이 행락 목적의 탐방객보다 윤리 의식이 높은 것을 확인할 수 있었다. This study was performed to identify the difference between purpose and ethics consciousness of national park visit through analysis of LNT(Leave No Trace) items. For this, case study was performed in the Baekyangsa and Namchang district in Naejang national park. Study methods were questionnaire and statistic analyses. Through these, the difference of Ethics Consciousness of national park visit according to visit purpose of one was identified. In other words, it was identified that visitors for climbing purpose had higher than those for pleasure-making in Ethics Consciousness of National Park Visit.

대형 할인매장 주차장 이용만족도의 영향요인 분석

임준범 ( Joon Bum Lim ),이수범 ( Soo Beom Lee ),성정곤 ( Jung Gon Sung ),박준태 ( Jun Tae Park ) 한국안전학회(구 한국산업안전학회) 2012 한국안전학회지 Vol.27 No.4

This research has analyzed factors affecting customers` satisfaction when they use parking lots of big retailers so that, in case of constructing, operating or managing such retailers, proper measures can be come up with. The analysis has been implemented on the basis of survey, and influence factors including entry/exit lamp, parking cars`` traffic flow, parking type, pedestrians`` movement after parking and safety. Parking lot users`` satisfaction has been analyzed by using the Structural Equation Modelling and, as a result of it, in case of a detached or single building, pedestrians movement flow after parking contributed the most to the users`` satisfaction, while, in case of multipurpose complex, parking cars traffic flow has the most influential factor. It is interpreted that users of a single building put a bigger emphasis on entry to the shop and their way back to the parked area after their shopping while customers of multipurpose complex might have various purposes of visiting the place and there are relatively more cars so that they put more emphasis on traffic counterflow, other cars and pedestrians.

Clinical and Genetic Characteristics of Retinal Capillary Hemangioblastoma in Korean Patients

Sang Ha Lee(Sang Ha Lee),Kyu Hyung Park(Kyu Hyung Park),Se Joon Woo(Se Joon Woo),Sang Jun Park(Sang Jun Park),Kwangsic Joo(Kwangsic Joo) 대한안과학회 2022 Korean Journal of Ophthalmology Vol.36 No.6

Purpose: We investigated the clinical features of Korean patients with retinal capillary hemangioblastoma (RCH) and genetic variants of the von Hippel-Lindau (VHL) gene. Methods: A retrospective analysis was performed on patients with RCH from 2003 to 2021 at Seoul National University Bundang Hospital. Sporadic and hereditary RCH associated with VHL disease were classified based on the specific tumors and family history. Clinical features, including the location and number of RCH and bilateral involvement, were investigated. Multiplex ligation-dependent probe amplification and direct sequencing targeting the VHL gene were performed for six RCH cases associated with VHL disease. Results: A total of 18 patients (23 eyes) were enrolled in this study. The mean age at diagnosis was 37 ± 15 years. Twelve patients had hereditary RCH associated with VHL disease, and six patients had sporadic RCH. All five patients with bilateral RCH were clinically diagnosed with VHL disease, and 13 patients had unilateral RCH. Juxtapapillary RCH was only observed in patients with VHL. The most common complication of RCH was the epiretinal membrane, followed by the subretinal fluid. Pathogenic variants were identified in four patients. All three patients with type 1 VHL had the well-known missense mutation p.Glu70Lys, and one patient with type 2 VHL had the nonsense mutation p.Trp88Ter. Conclusions: In Korean patients with RCH, bilateral involvement and juxtapapillary RCH are highly likely to be associated with VHL disease. Because RCH may be the first clinical manifestation in patients with VHL, active genetic testing of the VHL gene and systemic evaluation are required.

Quantum-dot nanoprobes and AOTF based cross talk eliminated six color imaging of biomolecules in cellular system

Park, Solji,Arumugam, Parthasarathy,Purushothaman, Baskaran,Kim, Sung-Yon,Min, Dal-Hee,Jeon, Noo Li,Song, Joon Myong Elsevier 2017 Analytica chimica acta Vol.985 No.-

<P><B>Abstract</B></P> <P>Primary cell cultures mimic the physiology and genetic makeup of in-vivo tissue of origin, nonetheless, a complication in the derivation and propagation of primary cell culture limits its use in biological research. However, in-vitro models using primary cells might be a complement model to mimic in vivo response. But, conventional techniques such as western blot and PCR employed to study the expression and activation of proteins requires a large number of cells, hence repeated establishment and maintenance of primary culture are unavoidable. Quantum dot (Q-dot) and acousto-optic tunable filters (AOTF) based multiplex imaging system is a viable alternative choice to evaluate multiple signaling molecules by using a small number of cells. Q-dots have broad excitation and narrow emission spectra, which allows to simultaneously excite multiple Q-dots by using single excitation wavelength. The use of AOTF in the fluorescence detection system enables to scan the fluorescence emission intensity of a Q-dot at their central wavelength, this phenomenon effectively avoids spectral overlap among the neighboring Q-dots. When Q-dots are conjugated with antibodies it acts as effective sensing probes. To validate this, the expression pattern of p-JNK-1, p-GSK3β, p-IRS1ser, p-IRS1tyr, p-FOXO1, and PPAR-γ, involved in the insulin resistance were concurrently monitored in adipocyte and HepG2 co-cell culture model. The observed results clearly indicate that PPAR-γ is the critical component in the development of insulin resistance. Moreover, the results proved that developed Q-dot based AOTF imaging methodology is a sensible choice to concurrently monitor multiple signaling molecules with limited cell population.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Quantum dot (Q-dot) and acousto-optic tunable filters (AOTF) based six-colour imaging. </LI> <LI> Expression of PPAR-γ in adipocyte regulates insulin resistance in hepatic (HepG2) cells. </LI> <LI> Aspirin improved insulin sensitivity in adipocytes and HepG2 co-cell culture. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Low-Cost Nanoporous Cu₂ZnSnS₄ Thin-Film Counter Electrode for Dye-Sensitized Solar Cells

Park, Si-Nae,Sung, Shi-Joon,Yang, Kee-Jeong,Kang, Jin-Kyu,Kim, Dae-Hwan American Scientific Publishers 2016 Journal of nanoscience and nanotechnology Vol.16 No.10

<P>The Cu2ZnSnS4 thin film is a well-known and promising electrode material to substitute for the expensive Pt counter electrode used in dye-sensitized solar cells. In this work, we have proposed a novel nanoporous Cu2ZnSnS4 thin film prepared by a simple and non-toxic process for use as the counter-electrode material. The Cu2ZnSnS4 thin film was easily prepared by a simple spin coating process using a sol-gel precursor that consists of metal chlorides and thiourea, followed by thermal annealing. By manipulating the thermal annealing conditions, a Cu2ZnSnS4 thin film with unique nanoporous morphology could be realized, and this film was very effective as the counter electrode owing to its large surface area. Because the size of Cu2ZnSnS4 nanograins was affected by the thermal annealing temperature, the scale of the nanoporous structures of the Cu2ZnSnS4 counter electrode, which significantly affects the photovoltaic characteristics of dye-sensitized solar cells, could be controlled by manipulating the annealing temperature. The structure and morphology of nanoporous Cu2ZnSnS4 thin films were characterized via X-ray diffraction and scanning electron microscopy analysis, and the photovoltaic performance of dye-sensitized solar cells based on the nanoporous Cu2ZnSnS4 counter electrode was also investigated. The nanoporous Cu2ZnSnS4 counter electrode exhibited a power conversion efficiency of 4.494% under 100 mW/cm(2) AM 1.5 simulated light, V-oc of 0.610 V, J(sc) of 10.46 mA/cm(2), and FF of 70.44%, and this power conversion efficiency was comparable to that of a conventional Pt counter electrode (5.719%) for the same device configuration.</P>

Synchronization Improvement of Distributed Clocks in EtherCAT Networks

Sung-Mun Park,Hongju Kim,Hyoung-Woo Kim,Chang Nho Cho,Joon-Young Choi IEEE 2017 IEEE communications letters Vol.21 No.6

<P>The aim of this letter is to improve the performance of clock synchronization in EtherCAT networks. Although EtherCAT synchronizes the slave clocks to the reference clock using a distributed clock synchronization mechanism, a synchronization error still exists between them. We propose a method to estimate and significantly reduce this error. In addition, we implement the method within the existing synchronization mechanism without adding an excessive computational load. The experimental results for synchronization performance verify that the proposed method improves the accuracy of clock synchronization in EtherCAT networks.</P>

Efficacy and safety of fixed-dose combination therapy with olmesartan medoxomil and rosuvastatin in Korean patients with mild to moderate hypertension and dyslipidemia: an 8-week, multicenter, randomized, double-blind, factorial-design study (OLSTA-D RCT

Park, Jin-Sun,Shin, Joon-Han,Hong, Taek-Jong,Seo, Hong-Seog,Shim, Wan-Joo,Baek, Sang-Hong,Jeong, Jin-Ok,Ahn, Youngkeun,Kang, Woong-Chol,Kim, Young-Hak,Kim, Sang-Hyun,Hyon, Min-Su,Choi, Dong-Hoon,Nam, Dove Medical Press 2016 Drug design, development and therapy Vol.10 No.-

<P>The pill burden of patients with hypertension and dyslipidemia can result in poor medication compliance. This study aimed to evaluate the efficacy and safety of fixed-dose combination (FDC) therapy with olmesartan medoxomil (40 mg) and rosuvastatin (20 mg) in Korean patients with mild to moderate hypertension and dyslipidemia. This multicenter, randomized, double-blind, factorial-design study included patients aged ≥20 years with mild to moderate essential hypertension and dyslipidemia. Patients were randomly assigned to receive FDC therapy (40 mg olmesartan medoxomil, 20 mg rosuvastatin), 40 mg olmesartan medoxomil, 20 mg rosuvastatin, or a placebo. The percentage change from baseline in low-density lipoprotein cholesterol levels was compared between FDC therapy and olmesartan medoxomil, and the change from baseline in diastolic blood pressure was compared between FDC therapy and rosuvastatin 8 weeks after treatment. A total of 162 patients were included. The least square mean percentage change (standard error) from baseline in low-density lipoprotein cholesterol levels 8 weeks after treatment was significantly greater in the FDC than in the olmesartan medoxomil group (−52.3% [2.8%] vs −0.6% [3.5%], <I>P</I><0.0001), and the difference was −51.7% (4.1%) (95% confidence interval: −59.8% to −43.6%). The least square mean change (standard error) from baseline in diastolic blood pressure 8 weeks after treatment was significantly greater in the FDC group than in the rosuvastatin group (−10.4 [1.2] mmHg vs 0.1 [1.6] mmHg, <I>P</I><0.0001), and the difference was −10.5 (1.8) mmHg (95% confidence interval: −14.1 to −6.9 mmHg). There were 50 adverse events in 41 patients (22.7%) and eight adverse drug reactions in five patients (2.8%). The study found that FDC therapy with olmesartan medoxomil and rosuvastatin is an effective, safe treatment for patients with hypertension and dyslipidemia. This combination may improve medication compliance in patients with a large pill burden.</P>

Adsorbed Carbon Formation and Carbon Hydrogenation for CO2 Methanation on the Ni(111) Surface: ASED-MO Study

Sang Joon Choe*,Hae Jin Kang,Su-Jin Kim,Sung-Bae Park,Dong Ho Park,Do Sung Huh 대한화학회 2005 Bulletin of the Korean Chemical Society Vol.26 No.11

Using the ASED-MO (Atom Superposition and Electron Delocalization-Molecular Orbital) theory, we investigated carbon formation and carbon hydrogenation for CO2 methanation on the Ni (111) surface. For carbon formation mechanism, we calculated the following activation energies, 1.27 eV for CO2 dissociation, 2.97 eV for the CO, 1.93 eV for 2CO dissociation, respectively. For carbon methanation mechanism, we also calculated the following activation energies, 0.72 eV for methylidyne, 0.52 eV for methylene and 0.50 eV for methane, respectively. We found that the calculated activation energy of CO dissociation is higher than that of 2CO dissociation on the clean surface and base on these results that the CO dissociation step are the rate-determining of the process. The C-H bond lengths of CH4 the intermediate complex are 1.21 Å, 1.31 Å for the C…H(1), and 2.82 Å for the height, with angles of 105o for  H(1)CH and 98o for H(1)CH(1).