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Jung CH, Lee WJ, Hwang JY, Yu JH, Shin MS, Lee MJ, Jang JE, Leem J, Park JY, Kim HK. Assessment of the fatty liver index as an indicator of hepatic steatosis for predicting incident diabetes independently of insulin resistance in a Korean population. Diabet Med 2013; 30:428-35. [PMID: 23278318 DOI: 10.1111/dme.12104] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 10/24/2012] [Accepted: 12/18/2012] [Indexed: 02/06/2023]
Abstract
AIMS Fatty liver disease, especially non-alcoholic fatty liver disease, is considered to be the hepatic manifestation of the metabolic syndrome, both closely associated with insulin resistance. Furthermore, fatty liver disease assessed by ultrasonography is known to be a predictor of the development of Type 2 diabetes mellitus. However, it remains unclear whether fatty liver disease plays a role in the pathogenesis of Type 2 diabetes independently of insulin resistance. In this study, we investigated whether fatty liver disease assessed by the fatty liver index can predict the development of Type 2 diabetes independently of systemic insulin resistance. METHODS We examined the clinical and laboratory data of 7860 subjects without diabetes who underwent general routine health evaluations at the Asan Medical Center in 2007 and had returned for follow-up examinations in 2011. Fatty liver index was calculated using an equation that considers serum triglyceride levels, γ-glutamyltransferase, waist circumference and BMI. RESULTS During a 4-year period, 457 incident diabetes cases (5.8%) were identified. The odds ratios for the development of Type 2 diabetes were significantly higher in the group with a fatty liver index ≥ 60 (fatty liver index-positive) than in the group with a fatty liver index < 20 (fatty liver index-negative) after adjusting for various confounding variables including homeostasis model assessment of insulin resistance. Odds ratios were significant regardless of the insulin resistance status at baseline. CONCLUSIONS Our results suggest that fatty liver index as a simple surrogate indicator of hepatic steatosis is valuable in identifying subjects at high risk for Type 2 diabetes. In addition, fatty liver disease itself contributes to the development of Type 2 diabetes independently of systemic insulin resistance.
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Kim SA, Yu JH, Rhee MS. A rapid and simple screening method of Cronobacter spp. in cell suspension and tofu. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2013; 93:1520-1524. [PMID: 22936627 DOI: 10.1002/jsfa.5872] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 07/12/2012] [Accepted: 07/26/2012] [Indexed: 06/01/2023]
Abstract
BACKGROUND Cronobacter spp. causes illnesses such as neonatal meningitis, sepsis and necrotising enterocolitis that can be fatal in infants and neonates. Thus it is of great concern to the food industry, which requires a simple and miniaturised method for the rapid detection of Cronobacter spp. in food. RESULTS A simple and rapid method was developed for the quantitative estimation of Cronobacter spp. Cell suspension cultures and tofu inoculated with Cronobacter spp. as well as a mixed culture (Cronobacter spp. and other micro-organisms) were serially diluted twofold on microtitre plates. Kim and Rhee broth, containing salicin, was added to each well. After 16-18 h of incubation the colour of broth in the wells changed from purple to yellow owing to salicin fermentation by Cronobacter spp. Bacterial counts were predicted by analysing the end points (the last well number in a series of positive wells). The coefficients of determination (r(2)) between the conventional plating method and the current method had high degrees of correlation (0.954-0.963), suggesting that the latter method offers a reasonable quantification of Cronobacter spp. CONCLUSION The simple method developed in this study could be used for the efficient and rapid screening of Cronobacter spp. in the food industry.
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Li Y, Du Y, Yang HF, Yu JH, Xu XX. Re: CT-guided percutaneous core needle biopsy for small (≤20 mm) pulmonary lesions. A reply. Clin Radiol 2013; 68:e354. [PMID: 23510621 DOI: 10.1016/j.crad.2013.02.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Accepted: 02/06/2013] [Indexed: 10/27/2022]
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Cho JY, Ahn SH, Lee JW, Yu JH, Koh BS, Kim HJ, Lee JW, Son BH, Gong GY, Kim HH. Abstract P3-01-02: Correlation of Mammographic breast density and tumor characteristics in Korean breast cancer patients. Cancer Res 2012. [DOI: 10.1158/0008-5472.sabcs12-p3-01-02] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Introduction: Western studies have demonstrated high breast density as a strong risk factor for breast cancer, it is poorly understood whether breast density affects the diverse phenotypes of breast cancer. We examined the association between various tumor characteristics and mammographic breast density in women with breast cancer.
Methods: We conducted a cross-sectional analysis in 910 Korean women diagnosed with breast cancer to evaluate the associations between breast density and tumor size, lymph node status, lymphovascular invasion, histologic grade, estrogen receptor, progesterone receptor, HER2. Breast density was classified as fatty (percent density less than 50% by a computer-assisted thresholding program, named “Cumulus™”; n = 470) or dense (percent density 50% or more; n = 440) for the cancer-free breast at the time of operation. Logistic regression was used to examine whether the relationships were modified by adjustment for body mass index, age at diagnosis, age at first birth, menopausal status, history of breast-feeding, and breast cancer staging.
Results: Total 910 patients were involved, the mean age and median age at the operation was 48 years old (range 20–82), and the mean percent density was 48.09 (SD = 9.62 %: normally distributed, Kolmogorov-Smirnov test p = 0.32). Crude analysis shows that tumor size over than 0.5cm were more likely to have dense breasts compared with women with a tumor size <=0.5 cm (OR = 3.21, 95% CI = 1.59–6.45, p = 0.001 for tumor sizes 0.6–1.0cm; OR = 2.02, 95% CI = 1.09–3.74, p = 0.03 for tumor sizes 1.1–1.5cm; OR = 1.8, 95% CI = 0.97–3.33, p = 0.06 for tumor sizes 1.6–2.0cm; and OR = 1.64, 95% CI = 0.92–2.94, p = 0.1 for tumor sizes 2.1cm or more). PD and histologic grade shows reverse association between histologic grade 1 and grade 2,3. Progesteron receptor positive patients tend to have more dense(OR = 1.27, 95% CI=0.97–1.66, p = 0.07) breast than receptor negative patients, although after adjustment of age the statistical significant disappeared. Percent density was not significantly associated with, ER (p = 0.74), HER2 (p = 0.72).
Conclusion: These results suggest that breast density is associated with tumor size and histologic grade and progesterone receptor positivity. Additional studies are needed to address whether these associations are due to just density masking the detection of some tumors, biological causation, or both.
Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-01-02.
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Chrobak CP, Van Zeeland MA, Moyer RA, Yu JH. Restoring transmission of irradiated image fiber bundles. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:10E514. [PMID: 23127021 DOI: 10.1063/1.4733544] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Image fiber bundles are employed in fusion experiments and other high radiation environments where they are used to transmit an image from an unprotected objective lens to a radiation shielded camera. Due to their exposure to neutron and gamma radiation the transmission of these expensive image fiber bundles can rapidly degrade, especially at the shorter visible wavelengths, and require costly replacement. A cost-effective, non-destructive heat treatment process in which entire fiber bundles are heated gradually in air to 150°-200°C and held for tens of hours has been shown to recover much of the transmission lost due to the radiation induced absorption. The restoration process can be repeated multiple times without a loss in effectiveness, although some physical degradation of inter-fiber alignment has been observed. The results and the apparatus used for the successful restoration of the transmission of multiple image fiber bundles across their entire wavelength band will be presented.
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Xu M, Tynan GR, Diamond PH, Manz P, Holland C, Fedorczak N, Thakur SC, Yu JH, Zhao KJ, Dong JQ, Cheng J, Hong WY, Yan LW, Yang QW, Song XM, Huang Y, Cai LZ, Zhong WL, Shi ZB, Ding XT, Duan XR, Liu Y. Frequency-resolved nonlinear turbulent energy transfer into zonal flows in strongly heated L-mode plasmas in the HL-2A tokamak. PHYSICAL REVIEW LETTERS 2012; 108:245001. [PMID: 23004280 DOI: 10.1103/physrevlett.108.245001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Indexed: 06/01/2023]
Abstract
The absolute rate of nonlinear energy transfer among broadband turbulence, low-frequency zonal flows (ZFs) and geodesic acoustic modes (GAMs) was measured for the first time in fusion-grade plasmas using two independent methods across a range of heating powers. The results show that turbulent kinetic energy from intermediate frequencies (20-80 kHz) was transferred into ZFs and GAMs, as well as into fluctuations at higher frequencies (>80 kHz). As the heating power was increased, the energy transfer from turbulence into GAMs and the GAM amplitudes increased, peaked and then decreased, while the energy transfer into the ZFs and the ZFs themselves increased monotonically with heating power. Thus there exists a competition between ZFs and GAMs for the transfer of turbulent energy, and the transfer into ZFs becomes dominant as the heating power is increased. The poloidal-radial Reynolds stress and the mean radial electric field profiles were also measured at different heating powers and found to be consistent with the energy transfer measurement. The results suggest that ZFs play an important role in the low-to-high (L-H) plasma confinement transition.
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Yu JH, Ahn JH, Chung HH, Kim YW, Yu JS, Kim JS. A Case of Primary Lung Cancer Producing Alpha-fetoprotein. Tuberc Respir Dis (Seoul) 2012. [DOI: 10.4046/trd.2012.72.1.72] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Kim HJ, Yi OV, Koh BS, Yu JH, Lee JW, Son BH, Ahn SH. P3-09-06: Changes of Serum Vitamin D According to the Breast Cancer Treatment. Cancer Res 2011. [DOI: 10.1158/0008-5472.sabcs11-p3-09-06] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Background: Vitamin D deficiency is associated with increased breast cancer risk and decreased breast cancer survival. The purpose of this study was to determine the effect of breast cancer adjuvant treatment to the vitamin D status, as measured by the serum hydroxyvitamin D (25OHD) in breast cancer patients.
Patients and Methods: For 589 patients who was diagnosed as a non metastatic breast cancer in 2009 at the asan medical center, blood was prospectively analyzed in batches for serum 25 OHD level at basal and at 6 and 12month. We excluded the patients who took a vitamin D supplementation and got a neoadjuvant chemotherapy. Vitamin D sufficiency was defined as serum as 30ng/ml or greater, insufficiency as 20 to 29 ng/ml and insufficiency as less than 20ng/ml.
Results: At baseline, mean serum 25OHD was greater in summer (April to Oct) than Winter(Nov to May) (28.2ng/ml vs 32.9ng/ml respectively, p=0.000). The patients who did not get a chemotherapy and antihormonal therapy as baseline, the patient with chemotherapy showed decreased serum 25OHD level than who without chemotherapy in 6 month but not in 12 month (p=0.003, vs p=0.156 respectively). The patients who had taken anti-hormonal therapy showed significant increasing serum 25OHD in 6 month and 12 months (p=0.000 both). For the patients who got both chemotherapy and anti-hormonal therapy, the changes of serum 25OHD level is smaller than the patients who got a chemotherapy only.
For the patients who got a chemotherapy, 57% of patients were vitamin D sufficient at baseline, but 27% of patients in 6 month and 49% in 12 month (p=0.001).
Conclusion: Vitamin D status was worsen during chemotherapy but recovered after chemotherapy. Anti hormonal therapy make the serum vitamin D level increased. The translational research about the effect of chemotherapy and anti-hormonal therapy to the vitamin D status should be warranted.
Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-09-06.
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Manz P, Xu M, Müller SH, Fedorczak N, Thakur SC, Yu JH, Tynan GR. Plasma blob generation due to cooperative elliptic instability. PHYSICAL REVIEW LETTERS 2011; 107:195004. [PMID: 22181616 DOI: 10.1103/physrevlett.107.195004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Indexed: 05/31/2023]
Abstract
Using fast-camera measurements the generation mechanism of plasma blobs is investigated in the linear device CSDX. During the ejection of plasma blobs the plasma is dominated by an m=1 mode, which is a counterrotating vortex pair. These flows are known to be subject to the cooperative elliptic instability, which is characterized by a cooperative disturbance of the vortex cores and results in a three-dimensional breakdown of two-dimensional flows. The first experimental evidence of a cooperative elliptic instability preceding the blob-ejection is provided in terms of the qualitative evolution of the vortex geometries and internal wave patterns.
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Xu M, Tynan GR, Diamond PH, Holland C, Yu JH, Yan Z. Generation of a sheared plasma rotation by emission, propagation, and absorption of drift wave packets. PHYSICAL REVIEW LETTERS 2011; 107:055003. [PMID: 21867076 DOI: 10.1103/physrevlett.107.055003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Indexed: 05/31/2023]
Abstract
Collisional electron drift wave turbulence generates drift wave packet structures with density and vorticity fluctuations in the central plasma pressure gradient region of a linear plasma device. Tracking these packets reveals that they follow an outward directed spiral-shaped trajectory in the (r,θ) plane, are azimuthally stretched, and develop anisotropy as they approach an axisymmetric, radially sheared azimuthal flow located at the plasma boundary. Nonlinear energy transfer measurements and time-delay analysis confirm that structure absorption amplifies the sheared flow. Similar mechanisms likely operate at the edge of confined toroidal plasmas and should lead to the amplification of sheared flows at the boundary of these devices as well.
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Lee SA, Lee WJ, Kim EH, Yu JH, Jung CH, Koh EH, Kim MS, Park JY, Lee KU. Progression to insulin deficiency in Korean patients with Type 2 diabetes mellitus positive for anti-GAD antibody. Diabet Med 2011; 28:319-24. [PMID: 21309840 DOI: 10.1111/j.1464-5491.2010.03186.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS To investigate the rate of progression to insulin deficiency in Korean patients with Type 2 diabetes mellitus positive for anti-GAD antibody (GADA) and to determine the factors related to progression to insulin deficiency. METHODS We retrospectively analysed data on 87 GADA-positive and 87 age- and sex-matched GADA-negative patients with Type 2 diabetes. GADA-positive patients were further subclassified into high-titre (≥ 250 WHO units/ml) (n = 24) and low-titre (< 250 WHO units/ml) (n = 63) subgroups. Cox proportional hazard analysis was used to identify factors associated with progression to insulin deficiency. RESULTS Over a period of 6 years, two of 87 (2.3%) GADA-negative and 37 of 87 (42.5%) GADA-positive patients had progressed to insulin deficiency. The rate of progression to insulin deficiency was higher in the high-titre than in the low-titre subgroup (75.0 vs. 30.2%). Multivariate analysis in GADA-positive patients showed that high-titre GADA and low BMI at diagnosis were independent factors significantly related to progression to insulin deficiency. CONCLUSIONS The presence of GADA predicted the progression to insulin deficiency in Korean patients with Type 2 diabetes. In GADA-positive patients, high-titre GADA and low BMI were associated with this progression.
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Kim JS, Yu JH, Kim YS, Kim I, Ahn JH. Obstructive Fibrinous Tracheal Pseudomenbrane Mimicking Tracheal Stents. Tuberc Respir Dis (Seoul) 2011. [DOI: 10.4046/trd.2011.71.1.59] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Yan Z, Xu M, Diamond PH, Holland C, Müller SH, Tynan GR, Yu JH. Intrinsic rotation from a residual stress at the boundary of a cylindrical laboratory plasma. PHYSICAL REVIEW LETTERS 2010; 104:065002. [PMID: 20366825 DOI: 10.1103/physrevlett.104.065002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Indexed: 05/29/2023]
Abstract
An azimuthally symmetric radially sheared azimuthal flow is driven by a nondiffusive, or residual, turbulent stress localized to a narrow annular region at the boundary of a cylindrical magnetized helicon plasma device. A no-slip condition, imposed by ion-neutral flow damping outside the annular region, combined with a diffusive stress arising from turbulent and collisional viscous damping in the central plasma region, leads to net plasma rotation in the absence of momentum input.
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Yu JH, Van Zeeland MA. Spectrally filtered fast imaging of internal magnetohydrodynamic activity in the DIII-D tokamak. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2008; 79:10F516. [PMID: 19044661 DOI: 10.1063/1.2956983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The detailed poloidal structure of internal magnetohydrodynamic (MHD) modes is imaged using broadband visible bremsstrahlung emission from the core of the DIII-D tokamak. Spectral analysis of individual pixel time series recorded by a fast framing camera (up to 26,000 frames/s at 256x256 spatial resolution) is used to reconstruct two-dimensional images of mode amplitude. Application of this spectrally filtered fast imaging (SFFI) technique reveals spatially extended coherent structures that correspond to a (m,n)=(1,1) kink mode and a (2,1) neoclassical tearing mode rotating in the laboratory frame. The SFFI technique produces images with significantly less noise than images produced with the commonly used background subtraction method. Extension of SFFI to other core MHD events and coherent fluctuations in general is straightforward and could lead to further understanding of core MHD activity in fusion devices.
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Rudakov DL, Yu JH, Boedo JA, Hollmann EM, Krasheninnikov SI, Moyer RA, Muller SH, Pigarov AY, Rosenberg M, Smirnov RD, West WP, Boivin RL, Bray BD, Brooks NH, Hyatt AW, Wong CPC, Roquemore AL, Skinner CH, Solomon WM, Ratynskaia S, Fenstermacher ME, Groth M, Lasnier CJ, McLean AG, Stangeby PC. Dust measurements in tokamaks (invited). THE REVIEW OF SCIENTIFIC INSTRUMENTS 2008; 79:10F303. [PMID: 19044616 DOI: 10.1063/1.2969422] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Dust production and accumulation present potential safety and operational issues for the ITER. Dust diagnostics can be divided into two groups: diagnostics of dust on surfaces and diagnostics of dust in plasma. Diagnostics from both groups are employed in contemporary tokamaks; new diagnostics suitable for ITER are also being developed and tested. Dust accumulation in ITER is likely to occur in hidden areas, e.g., between tiles and under divertor baffles. A novel electrostatic dust detector for monitoring dust in these regions has been developed and tested at PPPL. In the DIII-D tokamak dust diagnostics include Mie scattering from Nd:YAG lasers, visible imaging, and spectroscopy. Laser scattering is able to resolve particles between 0.16 and 1.6 microm in diameter; using these data the total dust content in the edge plasmas and trends in the dust production rates within this size range have been established. Individual dust particles are observed by visible imaging using fast framing cameras, detecting dust particles of a few microns in diameter and larger. Dust velocities and trajectories can be determined in two-dimension with a single camera or three-dimension using multiple cameras, but determination of particle size is challenging. In order to calibrate diagnostics and benchmark dust dynamics modeling, precharacterized carbon dust has been injected into the lower divertor of DIII-D. Injected dust is seen by cameras, and spectroscopic diagnostics observe an increase in carbon line (CI, CII, C(2) dimer) and thermal continuum emissions from the injected dust. The latter observation can be used in the design of novel dust survey diagnostics.
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Holland C, Yu JH, James A, Nishijima D, Shimada M, Taheri N, Tynan GR. Observation of turbulent-driven shear flow in a cylindrical laboratory plasma device. PHYSICAL REVIEW LETTERS 2006; 96:195002. [PMID: 16803106 DOI: 10.1103/physrevlett.96.195002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2005] [Indexed: 05/10/2023]
Abstract
An azimuthally symmetric radially sheared plasma fluid flow is observed to spontaneously form in a cylindrical magnetized helicon plasma device with no external sources of momentum input. A turbulent momentum conservation analysis shows that this shear flow is sustained by the Reynolds stress generated by collisional drift turbulence in the device. The results provide direct experimental support for the basic theoretical picture of drift-wave-shear-flow interactions.
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Yu JH, O'Neil TM, Driscoll CF. Fluid echoes in a pure electron plasma. PHYSICAL REVIEW LETTERS 2005; 94:025005. [PMID: 15698185 DOI: 10.1103/physrevlett.94.025005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2004] [Indexed: 05/24/2023]
Abstract
Experimental observations of diocotron wave echoes on a magnetized electron column are reported, representing Kelvin wave echoes on a rotating near-ideal fluid. The echoes occur by reversal of an inviscid wave damping process, and the phase-space mixing and unmixing are directly imaged. The basic echo characteristics agree with a simple nonlinear ballistic theory. At late times, the echo is degraded, and the maximal observed echo times agree with a theory of electron-electron collisions acting on separately evolving velocity classes.
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Hajós-Korcsok E, Robinson DD, Yu JH, Fitch CS, Walker E, Merchant KM. Rapid habituation of hippocampal serotonin and norepinephrine release and anxiety-related behaviors, but not plasma corticosterone levels, to repeated footshock stress in rats. Pharmacol Biochem Behav 2003; 74:609-16. [PMID: 12543226 DOI: 10.1016/s0091-3057(02)01047-x] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Prior stress exposure is known to alter the activation response to a subsequent stressor. In the present study, we examined neurochemical, neuroendocrinological, and behavioral correlates of short-term adaptation to homotypic stressors administered 60 min apart. An initial electric footshock significantly induced extracellular levels of both serotonin (5-HT) and norepinephrine (NE) in the rat hippocampus (650% and 200% above baseline, respectively), as measured by in vivo microdialysis. A rapid habituation in this response was evident in the inability of a second footshock to evoke similar increases. In contrast, the hypothalamic-pituitary-adrenal (HPA) response was augmented further after the second shock session: plasma corticosterone (CORT) levels were 18.1, 316.5, and 441.6 mg/ml in nonstressed, one-footshock-, or two-footshock-treated rats, respectively. In a social interaction paradigm, rats subjected to a single footshock showed several fear- and anxiety-related behaviors such as increases in freezing and decreases in rearing and active approach for social interaction. Exposure to a second footshock completely blocked the freezing response and restored rearing behavior without affecting the disruption in social interactions. Taken together, these data raise the possibility that neurochemical and neuroendocrine adaptations to short-term homotypic stressors differentially contribute to expression of different fear and anxiety-like responses in the rat.
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Gowri PM, Yu JH, Shaufl A, Sperling MA, Menon RK. Recruitment of a repressosome complex at the growth hormone receptor promoter and its potential role in diabetic nephropathy. Mol Cell Biol 2003; 23:815-25. [PMID: 12529387 PMCID: PMC140700 DOI: 10.1128/mcb.23.3.815-825.2003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The growth hormone (GH)-GH receptor (GHR) axis modulates growth and metabolism and contributes to complications of diabetes mellitus. We analyzed the promoter region of the dominant transcript (L2) of the murine GHR to determine that a cis element, L2C1, interacts with transcription factors NF-Y, BTEB1, and HMG-Y/I. These proteins individually repress GHR expression and together form a repressosome complex in conjunction with mSin3b. The histone deacetylase inhibitor trichostatin A increases expression of the murine GHR gene, enhances association of acetyl-H3 at L2C1, inhibits formation of the repressosome complex, and decreases NF-Y's association with L2C1. Our studies reveal that murine models of experimental diabetes mellitus are characterized by reduced hepatic GHR expression, decreased acetyl-H3 associated with L2C1, and increased formation of the repressosome complex. In contrast, in the kidney diabetes mellitus is associated with enhanced GHR expression and lack of alteration in the assembly of the repressosome complex, thus permitting exposure of kidneys to the effects of elevated levels of GH in diabetes mellitus. Our findings define a higher-order repressosome complex whose formation correlates with the acetylation status of chromatin histone proteins. The delineation of the role of this repressosome complex in regulating tissue-specific expression of GHR in diabetes mellitus provides a molecular model for the role of GH in the genesis of certain microvascular complications of diabetes mellitus.
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Lew R, Tanjasiri SP, Kagawa-Singer M, Yu JH. Using a stages of readiness model to address community capacity on tobacco control in the Asian American and Pacific Islander community. ASIAN AMERICAN AND PACIFIC ISLANDER JOURNAL OF HEALTH 2002; 9:66-73. [PMID: 11720416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
OBJECTIVES This paper describes the Asian Pacific Partners for Empowerment and Leadership (APPEAL) Stages of Community Readiness Model, a framework for assessing and evaluating tobacco control in the diverse Asian American and PaCific Islander (AAPI) communities. METHODS This model extends the work of existing community capacity models by applying a "stage of readiness" continuum of the five stages of pre-contemplation, contemplation, preparation, action and maintenance in terms of developing, launching and sustaining AAPI tobacco control efforts. FINDINGS The APPEAL Model allows communities to diagnose, then address their unique needs through appropriate technical assistance, training and resources. The APPEAL Model benefits both communities and funders through its ability to better understand their readiness to conduct tobacco control and have realistic expectations on the outcomes of those efforts. CONCLUSIONS This paper describes the elements of the Readiness model for AAPIS, particularly those addressing research and data issues, current applications of the model in specific AAPI ethnic communities, and the lessons learned thus far regarding the model's applicability to, and support of, the development of AAPI tobacco control efforts nationally.
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Kabantsev AA, Driscoll CF, Hilsabeck TJ, O'Neil TM, Yu JH. Trapped-particle asymmetry modes in single-species plasmas. PHYSICAL REVIEW LETTERS 2001; 87:225002. [PMID: 11736404 DOI: 10.1103/physrevlett.87.225002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2001] [Indexed: 05/23/2023]
Abstract
Novel trapped-particle asymmetry modes propagate on cylindrical electron columns when axial variations in the wall voltage cause particle trapping. These modes consist of E x B drifts of edge-trapped particles, partially shielded by axial flows of interior untrapped particles. A simple model agrees well with the observed frequencies and eigenfunctions, but the strong mode damping is as yet unexplained. These modes may be important in coupling trap asymmetries to particle motions and low frequency E x B drift modes.
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Sun WS, Lee HS, Park JM, Kim SH, Yu JH, Kim JH. YUA001, a novel aldose reductase inhibitor isolated from alkalophilic Corynebacterium sp. YUA25. II. Chemical modification and biological activity. J Antibiot (Tokyo) 2001; 54:827-30. [PMID: 11776438 DOI: 10.7164/antibiotics.54.827] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of novel N-substituted tyramine (2-p-hydroxyphenylethylamine) derivatives (1 to approximately 11) were synthesized and evaluated for their inhibitory activity against pig kidney aldose reductase (EC 1, 1, 1, 21). Of these compounds, N-2-p-hydroxyphenylethyl maleamic acid (10) exhibits the strongest aldose reductase inhibitory activity, which is 22 times more potent than that of YUA001.
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Han KH, Han KY, Yu JH, Chae KS, Jahng KY, Han DM. The nsdD gene encodes a putative GATA-type transcription factor necessary for sexual development of Aspergillus nidulans. Mol Microbiol 2001; 41:299-309. [PMID: 11489119 DOI: 10.1046/j.1365-2958.2001.02472.x] [Citation(s) in RCA: 153] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The ability to reproduce both sexually and asexually is one of the characteristics of the homothalic ascomycete Aspergillus nidulans. Unlike the other Aspergillus species, A. nidulans undergoes sexual development that seems to be regulated by internal and external stimuli. To begin to understand the sexual reproduction of A. nidulans we previously isolated and characterized several NSD (never in sexual development) mutants that failed to produce any sexual reproductive organs, and identified four complementation groups, nsdA, nsdB, nsdC, and nsdD. The nsdD gene has been isolated, and it is predicted to encode a GATA-type transcription factor with the type IVb zinc finger DNA-binding domain. The mRNA of the nsdD gene started to accumulate in the early phase of vegetative growth, and the level increased as sexual development proceeded. However, it decreased during asexual sporulation and no nsdD mRNA was detected in conidia. Deletion of nsdD resulted in no cleistothecia (fruiting bodies) formation, even under the conditions that preferentially promoted sexual development, indicating that nsdD is necessary for sexual development. In contrast, when the nsdD gene was over-expressed, sexual-specific organ (Hülle cell) was formed even in submerged culture, which normally completely blocked sexual development, and the number of cleistothecia was also dramatically increased on solid medium. These results lead us to propose that the nsdD gene functions in activating sexual development of A. nidulans. Multiple copies of the nsdD gene could suppress nsdB5 and veA1, indicating that either nsdD acts downstream of these genes or possibly functions in overlapping pathway(s).
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Chen GC, Guan LS, Yu JH, Li GC, Choi Kim HR, Wang ZY. Rb-associated protein 46 (RbAp46) inhibits transcriptional transactivation mediated by BRCA1. Biochem Biophys Res Commun 2001; 284:507-14. [PMID: 11394910 DOI: 10.1006/bbrc.2001.5003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The retinoblastoma suppressor (Rb)-associated protein 46 (RbAp46) is a member of the WD-repeat protein family and a component of the histone modifying and remodeling complexes. Previously, we demonstrated that RbAp46 is a potent growth inhibitor that can suppress the transformed phenotype of tumor cells. To explore the molecular mechanisms of RbAp46 function, we used RbAp46 as a bait in a yeast two-hybrid screening and found that RbAp46 interacts specifically with the C-terminal region of BRCA1 (the BRCT domain), a domain involved in the t transactivation activity of BRCA1. Coimmunoprecipitation assays demonstrated that the interaction of RbAp46 with BRCA1 requires the first two of the four Trp-Asp (WD)-repeats of RbAp46. We also showed that expression of RbAp46 represses the transactivation activity mediated by the BRCT/Gal4 fusion protein and inhibits the transactivation of the p21 promoter mediated by the full-length BRCA1. Interestingly, the association of BRCA1 and RbAp46 is disrupted in cells treated with DNA-damaging agents. These results suggest that RbAp46 may specifically interact with BRCA1 and modulate its transactivation activity in response to DNA damage.
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Yu JH, Lim HK, Choi GJ, Cho KY, Kim JH. A new method for assessing foliar uptake of fungicides using Congo Red as a tracer. PEST MANAGEMENT SCIENCE 2001; 57:564-9. [PMID: 11407035 DOI: 10.1002/ps.327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
In order to develop a new method for measuring foliar uptake of fungicides, Congo Red was selected as a tracer, and optimum procedures were established for washing, extracting and analyzing it and fungicides from leaf surfaces. Congo Red, a water-soluble dye, was not absorbed into cucumber or rice leaf, even in the presence of various surfactants, and was completely washable from leaf surfaces by aqueous acetonitrile solutions. Congo Red and fungicides in washings were quantified to calculate the amount of foliar uptake of the latter, by comparing the ratio to Congo Red. The optimum concentration of Congo Red in a formulation should be established in order to minimize its influence on fungicide uptake. Although Congo Red has proved to be useful with a conventional droplet application method, it will give more realistic and practical results with the spraying method used in the present study.
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