• Title/Summary/Keyword: IRS-2

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Infrared Study of a Low-mass Star-forming Region L1251B

  • Choi, Yunhee;Lee, Jeong-Eun;Bergin, Edwin A.;Blake, Geoffrey A.;Boogert, A.C. Adwin;Francesco, James Di;Evans, Neal J. II;Pontoppidan, Klaus M.;Sargent, Annelia I.
    • The Bulletin of The Korean Astronomical Society
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    • v.41 no.2
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    • pp.56.1-56.1
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    • 2016
  • A low-mass star-forming region, L1251B, is an excellent example of a small and nearby group of protostellar objects. L1251B has been mapped spectroscopically with the Infrared Spectrograph (IRS) onboard the Spitzer Space Telescope. IRS has provided mid-IR emission lines (e.g., [Fe II], [Ne II], and ro-vibrational H2) and absorption features of CO2 and H2O ice in studying the physical state of the ionized gas and the material residing in the circumstellar environments. We will present the distribution of outflows and ice components in L1251B.

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Spitzer IRS mapping of L1251B

  • Lee, Jeong-Eun
    • The Bulletin of The Korean Astronomical Society
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    • v.35 no.1
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    • pp.58.2-58.2
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    • 2010
  • L1251B, which was revealed as a small group of protostars by the Spitzer Space Telescope (SST), presents a great site of studying chemical evolution in gas and ice as well as various dynamical processes associated with star formation (infall, rotation, and outflow). We have mapped L1251B with the Infrared Spectrograph (IRS) aboard the SST to study the chemical distribution in the phases of gas and ice and the dynamical feature related to shock in the region. Various atomic lines and the $H_2$ pure rotational lines, which trace different shock velocities, were detected. In addition, the distribution of the water and $CO_2$ ices hints variety of the ice desorption mechanism in L1251B.

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The effects of Atractylodes japonica Koidz. on type 2 diabetic rats (창출이 제 2형 당뇨병 흰쥐에 미치는 영향)

  • Lee, Dae Hoon;Han, Jae Min;Yang, Woong Mo
    • The Journal of Korean Medicine
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    • v.36 no.1
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    • pp.75-85
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    • 2015
  • Objectives: Type 2 diabetes mellitus is a metabolic disease characterized by insulin resistance and high blood glucose level from progressive insulin secretory defect. The rhizome of Atractylodes japonica Koidz. (AJ) has been used for treatment of retention of water in oriental medicine. The aim of this study is to examine the effects of AJ on type 2 diabetes rats. Methods: Type 2 diabetes was induced by 60% high fat diet and low dose streptozotocin. Rats were divided into 4 groups (n = 6); Nor (normal control group), Con (diabetic group treated with vehicle), Met (diabetic group treated with 200 mg/kg metformin) and AJ (diabetic group treated with 100 mg/kg AJ). The body weights and food intakes were measured during the treatment period. After 4 weeks treatment, blood glucose level, HOMA-IR, and protein expressions of IRS-1, p-IRS-1, PPAR-${\gamma}$, and GLUT4 were measured, and histopathological examination of beta cell was performed. Results: Compared with the control group, blood glucose level and HOMA-IR were reduced in rats treated with AJ. Impaired beta cells in pancreas of rats were recovered and phosphorylation of IRS-1 was increased in rats treated with AJ. And also, protein expressions of PPAR-${\gamma}$ and GLUT4 were increased by treatment of AJ. Conclusions: The results suggest that Atractylodes japonica Koidz. may have anti-diabetic effect on type 2 diabetic rats through regulation of blood glucose level and insulin resistance. Therefore Atractylodes japonica Koidz. may have positive effects on patients with type 2 diabetes.

A Small group of protostellar objects: L1251C

  • Kim, Jungha;Lee, Jeong-Eun;Choi, Minho
    • The Bulletin of The Korean Astronomical Society
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    • v.38 no.2
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    • pp.66.1-66.1
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    • 2013
  • We present various observational results toward a small group of Young Stellar Objects (YSOs), L1251C. Observations by Spitzer Space Telescope legacy program "From Molecular Cores to Planet Forming Disks" (c2d; Evans et al. 2003) revealed that there are three YSOs within ~15" in L1251C: IRS1 (Class I), IRS2 (Class II), and IRS3 (Class II). In order to understand the molecular environment around these YSOs, we carried out the KVN single-dish observations in $HCO^+$ J=1-0, $H^{13}CO^+$ J=1-0, $N_2H^+$ J=1-0 and HCN J=1-0. $^{12}CO$ J=1-0 was also mapped in L1251C with the TRAO 14m telescope. Integrated intensity maps of high density tracers such as $H^{13}CO^+$ J=1-0, $N_2H^+$ J=1-0 and HCN J=1-0 show similar emission distributions, whose peaks are off the positions of YSOs. A compact $HCO^+$ J=1-0 outflow and an extended $^{12}CO$ J=1-0 outflow were observed, but their outflow axes are not cosistent ($HCO^+$: NW-SE, $^{12}CO$: EW). However, the highest velocity component of the $^{12}CO$ J=1-0 outflow shows similar morphology to the $HCO^+$ J=1-0 outflow, and ~ 23 % of $^{12}CO$ outflow momentum flux is loaded onto this high velocity component. Furthermore, continuum emission has been observed at 350, 450, 850 ${\mu}m$, and 1.3mm. With the KVN single dish, the 22 GHz $H_2O$ maser emission has been also monitored toward L1251C to find variations of the systemic velocity and intensity with time.

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Small group of protostellar objects: L1251C

  • Kim, Jungha;Lee, Jeong-Eun;Choi, Minho
    • The Bulletin of The Korean Astronomical Society
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    • v.38 no.1
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    • pp.51.1-51.1
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    • 2013
  • We present molecular line observations of a small group of Young Stellar Objects (YSOs), L1251C. Observations by Spitzer Space Telescope legacy program "From Molecular Cores to Planet Forming Disks"(c2d; Evans et al. 2003) revealed that there are three YSOs within ~15" in L1251C: IRS1 (Class I), IRS2 (Class II), and IRS3 (Class II). In order to understand the molecular environment around these YSOs, we carried out the KVN single-dish observations in $HCO^+$ J=1-0, $H^{13}CO^+$ J=1-0, $N_2H^+$ J=1-0 and HCN J=1-0. CO J=1-0 was also mapped in L1251C with the TRAO 14m telescope. Integrated intensity maps of high density tracers such as $H^{13}CO^+$ J=1-0, $N_2H^+$ J=1-0 and HCN J=1-0 show similar emission distributions, whose peaks are off from the positions of YSOs. However, $HCO^+$ J=1-0, which is believed to trace both infall and outflow, presents its emission distribution different from those of other molecular transitions. The line profile of $HCO^+$ J=1-0 is superimposed by two velocity (narrow and broad) components. The $HCO^+$ outflow map reveals multiple structures while the CO outflow map elongates mainly along the EW direction. With the KVN single dish, the 22 GHz $H_2O$ maser emission has been also monitored toward L1251C to find variations of the systemic velocity and intensity with time.

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Islamic Religiosity Scale, and Its Applied on the Relationship between Religiosity and Selection of Islamic Bank

  • Usman, Hardius
    • Journal of Distribution Science
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    • v.14 no.2
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    • pp.23-32
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    • 2016
  • Purpose - The purposes of this research are to develop a measurement of Islamic religiosity and apply these measurements to examine the relationship between religiosity and selection of the Islamic bank. Research design, data, and methodology - Literature searches and in-depth interviews are used to obtain the statement items to build measurement. Furthermore, the result of religiosity measurement will be used to study the relationship between religiosity and the selection of the Islamic bank. Population of the study is Muslim who has bank(s) account. A total 375 questionnaires were distributed to the three groups of bank customers (125 respondents in each group). Result -This research has successfully developed a measurement of religiosity, which is called Islamic Religiosity Scale (IRS). Based on IRS, this study found that religiosity has a significant relationship to the selection of Islamic banks. Conclusions - The study indicates that religiosity plays a significant role on the decision of customers to choose Islamic banks. Nevertheless, this study also revealed that religiosity is not the only factor that influences customers to selecting the Islamic banks.

Magnetic Fields of the Youngest Protostellar System L1448 IRS 2 revealed by ALMA

  • Kwon, Woojin;Stephens, Ian W.;Tobin, John J.;Looney, Leslie W.;Li, Zhi-Yun;Crutcher, Richard M.;Kim, Jongsoo;van der Tak, Floris F.S.
    • The Bulletin of The Korean Astronomical Society
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    • v.43 no.1
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    • pp.44.3-45
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    • 2018
  • Magnetic fields affect star formation in a broad range of scales from parsec to hundreds au. In particular, interferometric observations and ideal magneto-hydrodynamic (MHD) simulations have reported that formation of a rotation-supported disk at the earliest young stellar objects (YSOs) is largely suppressed by magnetic fields aligned to the rotational axis of YSOs: magnetic braking. Our recent ALMA observations toward L1448 IRS 2, which has a rotation detected and its magnetic fields aligned to the rotation axis (poloidal fields) in ~500 au scales, show that the fields switch to toroidal at the center in ~100 au scales. This result suggests that magnetic braking may not be so catastrophic for early disk formation even in YSOs with magnetic fields aligned to the rotational axis.

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Effect of Prunetin on Streptozotocin-Induced Diabetic Nephropathy in Rats - a Biochemical and Molecular Approach

  • Jose Vinoth Raja Antony Samy;Nirubama Kumar;Sengottuvelu Singaravel;Rajapandiyan Krishnamoorthy;Mohammad A Alshuniaber;Mansour K. Gatasheh;Amalan Venkatesan;Vijayakumar Natesan;Sung-Jin Kim
    • Biomolecules & Therapeutics
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    • v.31 no.6
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    • pp.619-628
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    • 2023
  • In the modern era, chronic kidney failure due to diabetes has spread across the globe. Prunetin (PRU), a component of herbal medicines, has a broad variety of pharmacological activities; these may help to slow the onset of diabetic kidney disease. The anti-nephropathic effects of PRU have not yet been reported. The present study explored the potential nephroprotective actions of PRU in diabetic rats. For 28 days, nephropathic rats were given oral doses of PRU (20, 40, and 80 mg/kg). Body weight, blood urea, creatinine, total protein, lipid profile, liver marker enzymes, carbohydrate metabolic enzymes, C-reactive protein, antioxidants, lipid peroxidative indicators, and the expression of insulin receptor substrate 1 (IRS-1) and glucose transporter 2 (GLUT-2) mRNA genes were all examined. Histological examinations of the kidneys, liver, and pancreas were also performed. The oral treatment of PRU drastically lowered the blood glucose, HbA1c, blood urea, creatinine, serum glutamic-oxaloacetic transaminase, serum glutamic pyruvic transaminase, alkaline phosphatase, lipid profile, and hexokinase. Meanwhile, the levels of fructose 1,6-bisphosphatase, glucose-6-phosphatase, and phosphoenol pyruvate carboxykinase were all elevated, but glucose-6-phosphate dehydrogenase dropped significantly. Inflammatory marker antioxidants and lipid peroxidative markers were also less persistent due to this administration. PRU upregulated the IRS-1 and GLUT-2 gene expression in the nephropathic group. The possible renoprotective properties of PRU were validated by histopathology of the liver, kidney, and pancreatic tissues. It is therefore proposed that PRU (80 mg/kg) has considerable renoprotective benefits in diabetic nephropathy in rats.

Caulerpa okamurae ethanol extract improves the glucose metabolism and insulin sensitivity in vitro and in vivo (옥덩굴 에탄올 추출물의 당 대사 및 인슐린 민감성 개선효과)

  • Park, Chul-Min;Thakuri, Laxmi Sen;Rhyu, Dong-Young
    • Journal of Applied Biological Chemistry
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    • v.64 no.1
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    • pp.89-96
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    • 2021
  • The aim of this study is to examine the effect of Caulerpa okamurae ethanol extract (COE) on glucose metabolism and insulin sensitivity as one of the drug targets for treatment of type2 diabetes. COE significantly inhibited protein tyrosine phosphatase (PTP1B) and dipeptidyl peptidase-IV (DPP-IV) enzyme activities in vitro assay. Also, COE significantly enhanced the glucose uptake and the expression of insulin receptor substrate-1 (IRS-1) and glucose transporter4 (GLUT4) proteins in 3T3-L1 adipocytes or zebrafish larvae compared with control. In dexamethasone-induced resistance model of L6 myotubes, the protein expression of insulin signaling and glucose uptake was effectively increased by the treatment of COE. In contrast, the elevated phosphorylation of IRS-1 Ser307 was normally suppressed by treatment of COE. However, COE had no effect on insulin secretion in pancreatic beta cells. Thus, our results suggest that COE improves the glucose metabolism and insulin sensitivity through the regulation of insulin signaling and GLUT4 protein in insulin's target cells and zebrafish larvae.

EVIDENCES OF EPISODIC MASS ACCRETION IN LOW-LUMINOSITY EMBEDDED PROTOSTARS

  • Kim, Hyo Jeong;Evans, Neal J. II;Dunham, Michael M.;Lee, Jeong-Eun;Pontoppidan, Klaus M.
    • Publications of The Korean Astronomical Society
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    • v.27 no.4
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    • pp.177-179
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    • 2012
  • We present Spitzer IRS spectroscopy of $CO_2$ ice toward 19 young stellar objects (YSOs) with luminosity lower than $1L_{\odot}$. Pure $CO_2$ ice forms only at elevated temperatures, T > 20 K, and thus at higher luminosities. Current internal luminosities of YSOs with L < $1L_{\odot}$ do not provide such conditions out to radii of typical envelopes. Significant amounts of pure $CO_2$ ice would signify a higher past luminosity. We analyze $15.2{\mu}m$ $CO_2$ ice bending mode absorption lines in comparison to the laboratory data. We decompose pure $CO_2$ ice from 12 out of 19 young low luminosity sources. The presence of the pure $CO_2$ ice component indicates high dust temperature and hence high luminosity in the past. The sum of all the ice components (total $CO_2$ ice amount) can be explained by a long period of low luminosity stage between episodic accretion bursts as predicted in an episodic accretion scenario. Chemical modeling shows that the episodic accretion scenario explains the observed total $CO_2$ ice amount best.