환율 변동성 예측 모형의 실증분석 -원/달러 환율을 중심으로-

최생림 ( Sang Rim Choi ),형남원 ( Nam Won Hyung ) 한국국제경영학회 2003 國際經營硏究 Vol.14 No.1

Various volatility forecasting models were tested and compared using shor-term and long-term Korean won/US dollar exchange rates. EWMA model, like in other previous research, shows better estimates than GARCH-type time series models in short-term. In long-term analysis, the relative dominance of EWMA model decays rapidly and the power of FIGARCH model, among other GARCH models, proves to be superior due to its long memory reflecting mechanism.

오공약침의 안전성에 대한 임상적 연구

소기숙,최회강,박소영,고강훈,김성남,이옥자,윤민영,문형철,김성철,이정훈,나원경,So, Ki-suk,Choi, Hoi-kang,Park, So-young,Koh, Kang-hun,Kim, Sung-nam,Lee, Ok-ja,Yun, Min-young,Mun, Hyung-chul,Kim, Sung-chul,Lee, Jung-hun,Na, Won-kyung 대한침구의학회 2004 대한침구의학회지 Vol.21 No.1

Objective: Recently scolopendrid aquacupuncture has been a good effect on pain control but it has not been known about clinical safety. So, In order to prove the clinical safety of scolopendrid aquacupuncture, We have observed the physical reac-tion and clinical pathology test after scolopendrid aquacupuncture treatment. Methods: We analyzed physical reaction and clinical pathology test before and after Scolopendrid aquacupuncture treatment of 30 patients suffering from pain, who admitted department of Acupunture and Moxibustion, College of Oriental Medicine, Won-Kwang University Kwangju hospital. Results & Conclusions: The results were summarized as follows. 1) The distribution of sex was 14 males and 16 females, and the average of patients age was 46.2 years. 2) The distribution of symptom was lumbago, lumbago with radiating pain, nuchal pain and knee joint pain. 3) In the 30 patients treated with Scolopendrid aquacupuncture, hematologic test did not show remarkable change. 4) In the 30 patients treated with Scolopendrid aquacupuncture, Liver function test(AST, ALT, ALP) showed a slight decrease on the contrary, and abnormal rate showed a decrease of 1.0%(from 3.3% to 2.3%) compared with previous study. 5) In the 30 patients treated with Scolopendrid aquacupuncture, Renal function test(BUN, Cr) and abnormal rate(from 2.5% to 2.0%) showed a slight decrease on the contrary. 6) In the 30 patients treated with Scolopendrid aquacupuncture. Electrolyte were normal range before & after treatment. 7) In the results of the Urine analysis of 30 patients, Leukocyte, Protein. Glucose, Keton, Bilirubin, U-bilinogen were not detected before and after Scolopendrid aquacupuncture treatment, and the rest almost made no difference. 8) In the Physical reactions, all of the patients complained of pain of body partially, only one patient showed reddish and itch, but symptoms like those were entirely disappeared within 24 hours and whole body pain, swelling, headache, dizziness, fatigue and nausea was not observed.

Reference Values for Peripheral Blood Lymphocyte Subsets in a Healthy Korean Population

Choi, Joungbum,Lee, Su Jin,Lee, Yun A,Maeng, Hyung Gun,Lee, Jong Kyun,Kang, Yong Won The Korean Association of Immunobiologists 2014 Immune Network Vol.14 No.6

Flow cytometric immunophenotyping of peripheral blood lymphocyte subsets is a powerful tool for evaluating cellular immunity and monitoring immune-mediated diseases. The numbers and proportions of blood lymphocyte subsets are influenced by factors such as gender, age, ethnicity, and lifestyle. This study aimed to establish reference ranges for peripheral blood lymphocyte subsets in a healthy Korean population. Blood samples from 294 healthy adults were collected. Lymphocyte subsets were analyzed using a single-platform method with a flow cytometer; white blood cells and lymphocytes were analyzed using an automated hematology analyzer. The mean value of the white blood cell count was $5,665cells/{\mu}l$, and the mean values of the subtype counts (percentages) were as follows: lymphocytes, $1,928cells/{\mu}l$ (35.08%); $CD3^+$ cells, $1,305cells/{\mu}l$ (67.53%); $CD3^+CD4^+$ cells, $787cells/{\mu}l$ (40.55%); $CD3^+CD8^+$ cells, $479cells/{\mu}l$ (25.23%); $CD3^-CD19^+$ cells, $203cells/{\mu}l$ (10.43%); and $CD3^-CD56^+$ cells, $300cells/{\mu}l$ (15.63%). Additionally, the $CD4^+/CD8^+$ ratio was 1.81. In this study, gender and age significantly influenced blood lymphocyte subsets. Our results demonstrate that, as with other populations, a healthy Korean population has its own, region-specific, lymphocyte subset reference ranges.

Ferromagnet-Free All-Electric Spin Hall Transistors

Choi, Won Young,Kim, Hyung-jun,Chang, Joonyeon,Han, Suk Hee,Abbout, Adel,Saidaoui, Hamed Ben Mohamed,Manchon, Auré,lien,Lee, Kyung-Jin,Koo, Hyun Cheol American Chemical Society 2018 Nano letters Vol.18 No.12

<P>The spin field-effect transistor, an essential building block for spin information processing, shows promise for energy-efficient computing. Despite steady progress, it suffers from a low-output signal because of low spin injection and detection efficiencies. We demonstrate that this low-output obstacle can be overcome by utilizing direct and inverse spin Hall effects for spin injection and detection, respectively, without a ferromagnetic component. The output voltage of our all-electric spin Hall transistor is about two orders of magnitude larger than that of previously reported spin transistors based on ferromagnets or quantum point contacts. Moreover, the symmetry of the spin Hall effect allows all-electric spin Hall transistors to effectively mimic n-type and p-type devices, opening a way of realizing the complementary functionality.</P> [FIG OMISSION]</BR>

Anti-inflammatory effect of lovastatin is mediated via the modulation of NF-κB and inhibition of HDAC1 and the PI3K/Akt/mTOR pathway in RAW264.7 macrophages

Choi, Hyung-Wook,Shin, Pyung-Gyun,Lee, Ji-Hyun,Choi, Woo-Suk,Kang, Min-Jae,Kong, Won-Sik,Oh, Min-Ji,Seo, Yong-Bae,Kim, Gun-Do D.A. Spandidos 2018 INTERNATIONAL JOURNAL OF MOLECULAR MEDICINE Vol.41 No.2

<P> Lovastatin is a 3-hydroxy-3-methylglutaryl-CoA reductase inhibitor that is clinically used for the prevention of cardiovascular diseases. Although it has been reported that lovastatin has anti-inflammatory properties in several studies, how lovastatin regulates the inflammation is still unclear. To evaluate the effect of lovastatin on nitric oxide production (NO) in RAW264.7 macrophages, NO production assay was performed. Also, cell viability was measured to confirm cytotoxicity. Level of tumor necrosis factor-α (TNF-α) transcription was measured by reverse transcription polymerase chain reaction (RT-PCR) from total RNA in RAW264.7 cells. Western blot analysis and immunofluorescence staining were used to investigate the regulation of lovastatin on the expression, phosphorylation, and nuclear translocation of cellular proteins. The results of the present study revealed that lovastatin reduced nitric oxide production via the reduction of inducible nitric oxide synthase (iNOS) expression in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells. The mRNA level of TNF-α was reduced in presence of lovastatin. In addition, lovastatin downregulated histone deacetylase 1 (HDAC1), resulting in the accumulation of acetylated histone H3 and heat shock protein 70. Furthermore, the expression of phosphoinositide 3-kinase catalytic subunits α and β was reduced under lovastatin treatment, and the phosphorylation of Akt and mammalian target of rapamycin was consequently inhibited. Lovastatin also inhibited the phosphorylation of inhibitor of nuclear factor (NF)-κBα and the translocation of NF-κB into the nucleus. Therefore, the present study demonstrates that lovastatin inhibits the expression of pro-inflammatory mediators, including iNOS and TNF-α, through the suppression of HDAC1 expression, PI3K/Akt phosphorylation and NF-κB translocation in LPS-stimulated RAW264.7 macrophage cells. </P>

Reassessing the significance of the <i>PAH</i> c.158G>A (p.Arg53His) variant in patients with hyperphenylalaninemia

Choi, Rihwa,Lee, Jeongho,Park, Hyung-Doo,Park, Jong Eun,Kim, Yong Hyuk,Ki, Chang-Seok,Lee, Soo-Youn,Song, Junghan,Kim, Jong-Won,Lee, Dong Hwan De Gruyter 2017 Journal of pediatric endocrinology & metabolism Vol.30 No.11

<P>Background: The accurate interpretation of sequence variation is critical for successful molecular diagnoses. It is also fundamental to the accurate diagnosis and treatment of phenylketonuria (PKU). This study aims to evaluate the significance of the c.158G > A (p.Arg53His) variant in the PAH gene, which was previously reported to be a pathogenic mutation that results in decreased phenylalanine hydroxylase enzyme activity in hyperphenylalaninemia (HPA) patients. Methods: Seven unrelated Korean patients with HPA genotyped with the c.158G > A variant were included in this study. The variant c.158G > A was classified by the standards and guidelines for the interpretation of sequence variants by the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. Results: By both directly collecting genetic data and comprehensively reviewing the existing literature, we found that this variant is more appropriately classified as 'Likely benign' rather than pathogenic. The allele's frequency is 2.57% in the general Korean population, which was greater than expected for phenylketonuria. This variant was observed to be homozygous in healthy subjects and was also observed in cis with other pathogenic variants. It is common in East Asian populations (especially in Koreans) compared to Western populations. There is a possibility that it causes decreased enzyme activity without leading to the full pathology of phenylketonuria. Conclusions: This study expands our understanding of the consequences of variation in PAH and its relationship to HPA.</P>

Distributed processing of a GPS receiver network for a regional ionosphere map

Choi, Kwang Ho,Lim, Joon Hoo,Yoo, Won Jae,Lee, Hyung Keun IOP Pub 2018 Measurement science & technology Vol.29 No.1

<P>This paper proposes a distributed processing method applicable to GPS receivers in a network to generate a regional ionosphere map accurately and reliably. For accuracy, the proposed method is operated by multiple local Kalman filters and Kriging estimators. Each local Kalman filter is applied to a dual-frequency receiver to estimate the receiver’s differential code bias and vertical ionospheric delays (VIDs) at different ionospheric pierce points. The Kriging estimator selects and combines several VID estimates provided by the local Kalman filters to generate the VID estimate at each ionospheric grid point. For reliability, the proposed method uses receiver fault detectors and satellite fault detectors. Each receiver fault detector compares the VID estimates of the same local area provided by different local Kalman filters. Each satellite fault detector compares the VID estimate of each local area with that projected from the other local areas. Compared with the traditional centralized processing method, the proposed method is advantageous in that it considerably reduces the computational burden of each single Kalman filter and enables flexible fault detection, isolation, and reconfiguration capability. To evaluate the performance of the proposed method, several experiments with field collected measurements were performed.</P>

Higher Plasma Thrombospondin-1 Levels in Patients With Coronary Artery Disease and Diabetes Mellitus

Choi, Kyu-Young,Kim, Dong-Bin,Kim, Myung-Jun,Kwon, Bum-June,Chang, Seo-Yoon,Jang, Sung-Won,Cho, Eun-Joo,Rho, Tai-Ho,Kim, Jae-Hyung The Korean Society of Cardiology 2012 Korean Circulation Journal Vol.42 No.2

<P><B>Background and Objectives</B></P><P>Thrombospondin-1 (TSP-1) is associated with atherosclerosis in animals with diabetes mellitus (DM). But, no study has investigated the role of TSP-1 in human atherosclerosis. This study investigated the relationship among plasma TSP-1 concentration, DM, and coronary artery disease (CAD).</P><P><B>Subjects and Methods</B></P><P>The study involved 374 consecutive subjects with suspected CAD, who had undergone coronary angiography to evaluate effort angina. Patients were divided into four groups as follows: DM(-) and CAD(-), DM(-) and CAD(+), DM(+) and CAD(-), and DM (+) and CAD(+).</P><P><B>Results</B></P><P>We found that plasma TSP-1 levels were higher in patients with DM(+) and CAD(+) (n=103) than those in other patients (n=271) (p<0.01). A multivariate analysis showed that male gender {odds ratio (OR), 2.728; 95% confidence interval (CI), 1.035-7.187}, high density lipoprotein-cholesterol (OR, 0.925; 95% CI, 0.874-0.980), glycated hemoglobin (OR, 1.373; 95% CI, 1.037-1.817), and plasma TSP-1 (OR, 1.004; 95% CI, 1.000-1.008) levels were independently associated with the presence of CAD in patients with DM.</P><P><B>Conclusion</B></P><P>Plasma TSP-1 levels were higher in patients with DM(+) and CAD(+) than those in other patients, and plasma TSP-1 levels were independently associated with the presence of CAD in patients with DM. These findings show a possible link between human plasma TSP-1 concentration and CAD in patients with DM.</P>

Synthesis of Cyclopropyl Ester and Amide Substituted Pyrimidinediones as Protoporphyrinogen Oxidase-Inhibiting Herbicides

Won Hyung Lee,Young Bin Kwon,Kye Hwan Lee,Jong-Soo Choi,Young Bae Seu 대한화학회 2021 Bulletin of the Korean Chemical Society Vol.42 No.3

The protoporphyrinogen oxidase (PPO) enzyme is involved in the biosynthesis of chlorophyll and is an important target in research for development of new herbicides. In this study, new pyrimidinedione compounds with thioester tail group containing cyclopropyl moiety are synthesized from the commercially available 2-(1-(mercaptomethyl)cyclopropyl)acetic acid. The herbicidal activity of the synthesized compounds is also evaluated. Most of the synthesized compounds exhibit herbicidal activities against both monocot and dicot weeds. In particular, 10a showed similar activity to the control material, Saflufenacil. And when against the monocot weeds, Echinochloa crusgalli and Digitaria sanguinalis, 10a shows superior activity to Saflufenacil.

Proteomic Analysis and the Antimetastatic Effect of N-(4-methyl)phenyl-O-(4-methoxy)phenyl-thionocarbamate-Induced Apoptosis in Human Melanoma SK-MEL-28 cells

Choi, Su-La,Choi, Yun-Sil,Kim, Young-Kwan,Sung, Nack-Do,Kho, Chang-Won,Park, Byong-Chul,Kim, Eun-Mi,Lee, Jung-Hyung,Kim, Kyung-Mee,Kim, Min-Yung,Myung, Pyung-Keun 충남대학교 형질전환복제돼지연구센터 2007 논문집 Vol. No.10

We employed human SK-MEL-28 cells as a model system to identify cellular proteins that accompany N-(4-methyl)phenyl-O-(4-methoxy)phenyl-thionocarbamate (MMTC)-induced apoptosis based on a proteomic approach. Cell viability tests revealed that SK-MEL-28 skin cancer cells underwent more cell death than normal HaCaT cells in a dose-dependent manner after treatment with MMTC. Two-dimensional electrophoresis in conjunction with matrix-assisted laser desorption/ionization-time of flight (MALDl- TOF) mass spectrometry analysis or computer matching with a protein database further revealed that the MMTC-induced apoptosis is accompanied by increased levels of caspase-1, checkpoint suppressor-1, caspase-4, NF-κB inhibitor, AP-2, c-Jun-N-terminal kinase, melanoma inhibitor, granzyme K, G1/S specific eye/in D3, cystein rich protein, Ras-related protein Rab-37 or Ras-related protein Rab-13, and reduced levels of EMS (oncogene), ATP synthase, tyrosine-phosphatase, Cdc25c, 14-3-3 protein or specific structure of nuclear receptor. The migration suppressing effect of MMTC on SK-MEL-28 cell was tested. MMTC suppressed the metastasis of SK-MEL-8 cells. It was also identified that MMTC had little angiogenic effect because it did not suppress the proliferation of HUVEC cell line. These results suggest that MMTC is a novel chemotherapeutic and metastatic aoents aqainst the SK-MEL-28 human melanoma cell line.