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Search Results: 1 - 10 of 30593 matches for " Moon-Sun Im "
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The association between arterial stiffness and left ventricular filling pressure in an apparently healthy Korean population
Hack-Lyoung Kim, Moon-Sun Im, Jae-Bin Seo, Woo-Young Chung, Sang-Hyun Kim, Myung-A Kim, Joo-Hee Zo
Cardiovascular Ultrasound , 2013, DOI: 10.1186/1476-7120-11-2
Abstract: A total of 115 healthy subjects without known cardiovascular risk factors or overt heart disease who underwent both transthoracic echocardiography and brachial-ankle pulse wave velocity (baPWV) measurement at the same day during their routine check-ups were analyzed.The mean age of study subjects was 52.8 ± 8.4 years, and 78 (67.8%) were men. The mean baPWV value was 1,325 ± 185 cm/s. Study subjects were divided into 3 groups according to E/E’ value: subjects with E/E’ < 8, 8–12.9 and E/E’ ≥ 13. As E/E’ increased, baPWV value increased gradually: baPWV in subjects with E/E’ < 8, E/E’ 8–12.9 and E/E’ ≥ 13, were 1,261 ± 163, 1,345 ± 169, 1,569 ± 232 cm/s, respectively (p < 0.001). In multiple linear regression analyses, baPWV was significantly associated with E/E’ (β = 0.371, p < 0.001) after controlling confounders including age, sex and body mass index. In receiver-operating characteristic (ROC) curve analysis, the sensitivity and specificity for detection of E/E’ ≥ 10 were 78.6% and 59.8%, respectively with mean baPWV of 1,282 cm/s as the cut off value. The discriminatory capacity for predicting E/E’ ≥ 10 was improved from an area under the ROC curve of 0.646 with age alone to 0.734 when baPWV was added (p < 0.001).There is a significant association between baPWV and E/E’ in an apparently healthy Korean population. BaPWV is useful as a simple and non-invasive method for early detection of increased LV filling pressure among these people.Stiffened artery increases pulse pressure leading to left ventricular hypertrophy and coronary artery disease [1]. Arterial stiffness has been reported to be associated with cardiovascular morbidity and mortality [2,3].There are several methods to estimate arterial stiffness. Among them, pulse wave velocity (PWV) is generally accepted as the most simple, non-invasive and validated indicator of arterial stiffness [4,5]. Recently, the brachial-ankle PWV (baPWV) measurement, which is easy to perform, has become available in clinical pr
Impact of acute exercise on brachial artery flow-mediated dilatation in young healthy people
In-Chang Hwang, Kyung-Hee Kim, Won-Suk Choi, Hyun-Jin Kim, Moon-Sun Im, Yong-Jin Kim, Sang-Hyun Kim, Myung-A Kim, Dae-Won Sohn, Joo-Hee Zo
Cardiovascular Ultrasound , 2012, DOI: 10.1186/1476-7120-10-39
Abstract: Eighty-six young healthy volunteers were prospectively enrolled from January 2011 to December 2011. The subjects completed FMD tests at rest and immediately after treadmill exercise test. Primary outcome was the impact of acute exercise on FMD, measured by the difference of FMD before and after exercise. Secondary outcomes were the relationship of gender and exercise habit with FMD.Seventy-four subjects who met the eligibility criteria were included for analysis. Thirty-five (47.3%) were male, and the mean age was 22.7±2.7 years. FMD was reduced after exercise (8.98±4.69 to 7.51±4.03%; P=0.017) and the reduction was found in female group (10.36±5.26 to 7.62±3.71%; P=0.002) but not in male group. Post-exercise FMD was significantly impaired in subjects who did not exercise regularly (6.92±3.13% versus 8.95±5.33%; P=0.003). The decrease of FMD after exercise was greater in female group (?2.75±5.28% versus 0.27±3.24%; P=0.003) and was associated with exercise habit (β=2.532; P=0.027).In healthy young subjects, FMD was reduced after a bout of acute exercise. The impact of acute exercise showed significant differences according to gender and exercise habit. FMD impairment after acute exercise was observed in females and subjects without regular exercise.Endothelial dysfunction is an important factor in the development of atherosclerosis, hypertension, and coronary artery disease (CAD) [1-4]. Impaired endothelial function is observed in subjects with risk factors for atherosclerosis and in patients with essential hypertension [2,5,6]. Also it is an important predictor of long-term cardiovascular events [7,8].There are several methods to assess endothelial dysfunction and flow-mediated dilatation (FMD) is the most widely used non-invasive method to assess the endothelial function, reflecting the endothelial nitric oxide (NO) dependent vasodilation in response to occlusion-induced reactive hyperemia [5,9]. As FMD is non-invasive and reliable, allows repeated measurements [1
N,N′-Dimethyl-N,N′-bis(pyridin-2-yl)methanediamine
Moon-Sun Lee,Minyoung Yoon,O-bong Yang,Dong-Heon Lee
Acta Crystallographica Section E , 2011, DOI: 10.1107/s1600536811046320
Abstract: The title compound, C13H16N4, consists of two pyridine rings which are linked by an N,N′-dimethylmethaneamine chain. The pyridine rings adopt a twist conformation and the dihedral angle between them is 60.85 (5)°. The crystal packing is stabilized by weak C—H...π interactions.
Superconducting fluctuations in organic molecular metals enhanced by Mott criticality
Moon-Sun Nam,Cecile Meziere,Patrick Batail,Leokadiya Zorina,Sergey Simonov,Arzhang Ardavan
Physics , 2013,
Abstract: Unconventional superconductivity typically occurs in materials in which a small change of a parameter such as bandwidth or doping leads to antiferromagnetic or Mott insulating phases. As such competing phases are approached, the properties of the superconductor often become increasingly exotic. For example, in organic superconductors and underdoped high-$T_\mathrm{c}$ cuprate superconductors a fluctuating superconducting state persists to temperatures significantly above $T_\mathrm{c}$. By studying alloys of quasi-two-dimensional organic molecular metals in the $\kappa$-(BEDT-TTF)$_2$X family, we reveal how the Nernst effect, a sensitive probe of superconducting phase fluctuations, evolves in the regime of extreme Mott criticality. We find strong evidence that, as the phase diagram is traversed through superconductivity towards the Mott state, the temperature scale for superconducting fluctuations increases dramatically, eventually approaching the temperature at which quasiparticles become identifiable at all.
Dissipation in the superconducting state of kappa-(BEDT-TTF)2Cu(NCS)2
Liang Yin,Moon-Sun Nam,James G. Analytis,Stephen J. Blundell,Arzhang Ardavan,John A. Schlueter,Takahiko Sasaki
Physics , 2006, DOI: 10.1103/PhysRevB.76.014506
Abstract: We have studied the interlayer resistivity of the prototypical quasi-two-dimensional organic superconductor $\kappa$-(BEDT-TTF)$_2$Cu(NCS)$_2$ as a function of temperature, current and magnetic field, within the superconducting state. We find a region of non-zero resistivity whose properties are strongly dependent on magnetic field and current density. There is a crossover to non-Ohmic conduction below a temperature that coincides with the 2D vortex solid -- vortex liquid transition. We interpret the behaviour in terms of a model of current- and thermally-driven phase slips caused by the diffusive motion of the pancake vortices which are weakly-coupled in adjacent layers, giving rise to a finite interlayer resistance.
Superconducting properties and Fermi-surface topology of the quasi-two-dimensional organic superconductor $λ$-(BETS)$_{2}$GaCl$_{4}$
Charles Mielke,John Singleton,Moon-Sun Nam,Neil Harrison,C. C. Agosta,B. Fravel,L. K. Montgomery
Physics , 2001, DOI: 10.1088/0953-8984/13/36/308
Abstract: The Fermi surface topology of the organic superconductor \lbets has been determined using the Shubnikov-de Haas and magnetic breakdown effects and angle-dependent magnetoresistance oscillations. The former experiments were carried out in pulsed fields of up to 60 T, whereas the latter employed quasistatic fields of up to 30 T. All of these data show that the Fermi-surface topology of \lbets is very similar to that of the most heavily-studied organic superconductor, \cuscn, except in one important respect; the interplane transfer integral in \lbets is a factor $\sim 10$ larger than that in \cuscn . The increased three-dimensionality of \lbets is manifested in radiofrequency penetration-depth measurements, which show a clear dimensional crossover in the behaviour of $H_{c2}(T)$. The radiofrequency measurements have also been used to extract the Labusch parameter determining the fluxoid interactions as a function of temperature, and to map the flux-lattice melting curve.
Surface acoustic wave devices on bulk ZnO at low temperature
Einar B. Magnusson,Benjamin H. Williams,Riccardo Manenti,Moon-Sun Nam,Ani Nersisyan,Michael J. Peterer,Arzhang Ardavan,Peter J. Leek
Physics , 2014, DOI: 10.1063/1.4908248
Abstract: Surface acoustic wave (SAW) devices based on thin films of ZnO are a well established technology. However, SAW devices on bulk ZnO crystals are not practical at room temperature due to the significant damping caused by finite electrical conductivity of the crystal. Here, by operating at low temperatures, we demonstrate effective SAW devices on the (0001) surface of bulk ZnO crystals, including a delay line operating at SAW wavelengths of {\lambda} = 4 and 6 {\mu}m and a one-port resonator at a wavelength of {\lambda} = 1.6 {\mu}m. We find that the SAW velocity is temperature dependent, reaching $v \simeq 2.68$ km/s at 10mK. Our resonator reaches a maximum quality factor of $Q_i \simeq 1.5\times 10^5$, demonstrating that bulk ZnO is highly viable for low temperature SAW applications. The performance of the devices is strongly correlated with the bulk conductivity, which quenches SAW transmission above about 200 K.
Dissociation of Progressive Dopaminergic Neuronal Death and Behavioral Impairments by Bax Deletion in a Mouse Model of Parkinson's Diseases
Tae Woo Kim, Younghye Moon, Kyungjin Kim, Jeong Eun Lee, Hyun Chul Koh, Im Joo Rhyu, Hyun Kim, Woong Sun
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0025346
Abstract: Parkinson's disease (PD) is a common, late-onset movement disorder with selective degeneration of dopaminergic (DA) neurons in the substantia nigra (SN). Although the neurotoxin 6-hydroxydopamine (6-OHDA) has been used to induce progressive degeneration of DA neurons in various animal models of PD, the precise molecular pathway and the impact of anti-apoptotic treatment on this neurodegeneration are less understood. Following a striatal injection of 6-OHDA, we observed atrophy and progressive death of DA neurons in wild-type mice. These degenerating DA neurons never exhibited signs of apoptosis (i.e., caspase-3 activation and cytoplasmic release of cytochrome C), but rather show nuclear translocation of apoptosis-inducing factor (AIF), a hallmark of regulated necrosis. However, mice with genetic deletion of the proapoptotic gene Bax (Bax-KO) exhibited a complete absence of 6-OHDA-induced DA neuron death and nuclear translocation of AIF, indicating that 6-OHDA-induced DA neuronal death is mediated by Bax-dependent AIF activation. On the other hand, DA neurons that survived in Bax-KO mice exhibited marked neuronal atrophy, without significant improvement of PD-related behavioral deficits. These findings suggest that anti-apoptotic therapy may not be sufficient for PD treatment, and the prevention of Bax-independent neuronal atrophy may be an important therapeutic target.
Meteorin Regulates Mesendoderm Development by Enhancing Nodal Expression
Yoon-Young Kim, Jin-Sook Moon, Min-chul Kwon, Juhee Shin, Sun-Kyoung Im, Hyun-A Kim, Jin-Kwan Han, Young-Yun Kong
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0088811
Abstract: During gastrulation, distinct lineage specification into three germ layers, the mesoderm, endoderm and ectoderm, occurs through an elaborate harmony between signaling molecules along the embryonic proximo-distal and anterior-posterior axes, and Nodal signaling plays a key role in the early embryonic development governing embryonic axis formation, mesoderm and endoderm specification, and left-right asymmetry determination. However, the mechanism by which Nodal expression is regulated is largely unknown. Here, we show that Meteorin regulates Nodal expression and is required for mesendoderm development. It is highly expressed in the inner cell mass of blastocysts and further in the epiblast and extra-embryonic ectoderm during gastrulation. Genetic ablation of the Meteorin gene resulted in early embryonic lethality, presumably due to impaired lineage allocation and subsequent cell accumulation. Embryoid body culture using Meteorin-null embryonic stem (ES) cells showed reduced Nodal expression and concomitant impairment of mesendoderm specification. Meteorin-null embryos displayed reduced levels of Nodal transcripts before the gastrulation stage, and impaired expression of Goosecoid, a definitive endoderm marker, during gastrulation, while the proximo-distal and anterior-posterior axes and primitive streak formation were preserved. Our results show that Meteorin is a novel regulator of Nodal transcription and is required to maintain sufficient Nodal levels for endoderm formation, thereby providing new insights in the regulation of mesendoderm allocation.
The Effects of Thinning on Fine Root Distribution and Litterfall in a Pinus koraiensis Plantation
Byung Bae Park,Im Kyun Lee,Hee Moon Yang
Journal of Ecology and Field Biology , 2009,
Abstract: The purpose of this study was to investigate the effects of thinning on fine root biomass andvertical distribution and litterfall amount in a 50 year old Pinus koraiensis plantation in Chuncheon, KangwonProvince. Fine root (< 2 mm in diameter) biomass (367 g/m2) in the site ‘OC_75’, thinning once in 1975, was68% of those in the site ‘CON’, no thinning after planting, and in the site ‘TC_00’, thinning twice in 1975 and2000. There were no significant differences of dead roots among treatments. Diameter 0~1 mm roots werevertically decreased only in the TC_00 site. The litterfall was very similar between OC_75 (5.2 Mg ha-1 yr-1)and TC_00 (4.7 Mg ha-1 yr-1), but the composition of litterfall was different: The proportion of leaves andbranches was 80% and 13% in OC_75 and 56% and 36% in TC_00, respectively. Reduction of P. koraiensisdensity by thinning decreased leaf litter as well as fine roots of P. koraiensis, but increased fine roots productionby neighboring understory plants offset the reduction of fine roots of P. koraiensis. We suggest that belowgroundas well as aboveground responses, including both over- and understory vegetation, should be considered tomeasure the responses of trees in thinned forest ecosystems.
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