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Search Results: 1 - 10 of 29504 matches for " Hee Jung Lee "
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Light scalar mesons as tetraquarks within QCD Sum Rules
Lee, Hee-Jung
High Energy Physics - Phenomenology , 2007, DOI: 10.1143/PTPS.168.190
Abstract: We examine the interpretation of the light scalar meson nonet as tetraquark states using QCD sum rules. With the interpolating current for the tetraquark states composed of scalar diquark and scalar antidiquark, first, we construct the QCD sum rules by means of the operator product expansion up to the operators of dimension 8 and show that there is no evidence of the coupling of the tetraquark states to the light scalar meson nonet. In order to have a stable sum rule, we propose a "good" interpolating current for the tetraquarks based on chirality arguments which includes scalar and pseudoscalar diquark--antidiquarks with equal weights. In particular, for the lowest tetraquark $\sigma$--meson, we perform detail analysis of the QCD sum rule and obtain mass for the $\sigma(600)$ around 780 MeV.
The Proton Spin Problem in the Chiral Bag Model
Hee-Jung Lee
Physics , 2002,
Abstract: The flavor singlet axial charge has been a source of study in the last years due to its relation to the so called {\it Proton Spin Problem}. The relevant flavor singlet axial current is anomalous, i.e., its divergence contains a piece which is the celebrated $U_A(1)$ anomaly. This anomaly is intimately associated with the $\eta^\prime$ meson, which gets its mass from it. When the gauge degrees of freedom of QCD are confined within a volume as is presently understood, the $U_A(1)$ anomaly is known to induce color anomaly leading to "leakage" of the color out of the confined volume (or bag). For consistency of the theory, this anomaly should be cancelled by a boundary term. This ``color boundary term" inherits part or most of the dynamics of the volume (i.e., QCD). In this thesis, we exploit this mapping of the volume to the surface via the color boundary condition to perform a complete analysis of the flavor singlet axial charge in the chiral bag model using the Cheshire Cat Principle. This enables us to obtain the hitherto missing piece in the axial charge associated with the gluon Casimir effect. The result is that the flavor singlet axial charge is small independent of the confinement (bag) size ranging from the skyrmion picture to the MIT bag picture, thereby confirming the (albeit approximate) Cheshire Cat phenomenon.
Development of the Guideline for HIV Testing in South Korea with Low Prevalence of HIV-1 Infection Based on the Expert Consensus  [PDF]
Hee Jung Choi, Kyoung Ae Kong, Jung Won Min, Hun-Jae Lee, Hae-Sook Park
World Journal of AIDS (WJA) , 2011, DOI: 10.4236/wja.2011.14023
Abstract: Purpose: This study was conducted to develop a guideline for HIV testing in South Korea where the HIV prevalence is very low. It is necessary to make the recommendations presented here based on the epidemiology of opportunistic infection and cancer in the community. Methods: The development of a guideline for HIV testing was conducted using literature reviews and the agreement of Korean experts for HIV patients using a two-round Delphi consensus technique. Each expert was asked to independently answer to each item related to HIV risk. Ten experts participated in the two-round survey. Results: The individual items were determined based on the following categories: high risk behavior, symptom and diseases, colo-rectal diseases, uro-genital diseases and gynecology, skin and oral diseases. The final guideline consisted of 4-scale agreement rating (strongly recommended, recommended, not routinely recommended, no recommendation for routine provision). Discussion: We have developed the guideline for HIV testing in a country where the HIV prevalence is low based on a systematic investigation and expert consensus.
On the $\pi\pi$ contribution to the QCD sum rules for the light tetraquark
Lee, Hee-Jung;Kochelev, N. I.
High Energy Physics - Phenomenology , 2007, DOI: 10.1103/PhysRevD.78.076005
Abstract: We perform a QCD sum rule analysis for the $f_0$ light tetraquark taking into account the contribution arising from the two pion intermediate state. With the interpolating currents of the different chiral combinations of scalar and pseudoscalar diquarks, it is demonstrated that the interpolating current with maximum chirality has a large coupling to the two pion state, but the current with zero chirality interacts only weekly with this state. Taking into account the form factor in the $f_0$--two pion vertex, it is shown that the $f_0$--coupling to the two pion state leads to an increase of the lightest tetraquark mass by a value of about 100 MeV. The analysis of the resulting sum rule shows that the $\sigma(f_0(600))$--meson state might be treated as the four--quark bound state in the instanton field which has a rather strong coupling to the two pion state.
Selective patterning of ZnO nanorods on silicon substrates using nanoimprint lithography
Jung Mi-Hee,Lee Hyoyoung
Nanoscale Research Letters , 2011,
Abstract: In this research, nanoimprint lithography (NIL) was used for patterning crystalline zinc oxide (ZnO) nanorods on the silicon substrate. To fabricate nano-patterned ZnO nanorods, patterning of an n-octadecyltrichlorosilane (OTS) self-assembled monolayers (SAMs) on SiO2 substrate was prepared by the polymer mask using NI. The ZnO seed layer was selectively coated only on the hydrophilic SiO2 surface, not on the hydrophobic OTS SAMs surface. The substrate patterned with the ZnO seed layer was treated with the oxygen plasma to oxidize the silicon surface. It was found that the nucleation and initial growth of the crystalline ZnO were proceeded only on the ZnO seed layer, not on the silicon oxide surface. ZnO photoluminescence spectra showed that ZnO nanorods grown from the seed layer treated with plasma showed lower intensity than those untreated with plasma at 378 nm, but higher intensity at 605 nm. It is indicated that the seed layer treated with plasma produced ZnO nanorods that had a more oxygen vacancy than those grown from seed layer untreated with plasma. Since the oxygen vacancies on ZnO nanorods serve as strong binding sites for absorption of various organic and inorganic molecules. Consequently, a nano-patterning of the crystalline ZnO nanorods grown from the seed layer treated with plasma may give the versatile applications for the electronics devices.
Expression of MMP-9 and -13 on the Pressure Side under Orthodontic Loading  [PDF]
Su-Jung Mah, Yoonjung Lee, Youn-Sic Chun, Won Hee Lim
Open Journal of Stomatology (OJST) , 2014, DOI: 10.4236/ojst.2014.48055
Abstract: Purpose: The purpose of this study was to investigate the expression of MMP-9 and MMP-13 on compression side of tooth movement. Material and Methods: Twenty male Wistar rats were used for this experiment. Maxillary right first molar was moved orthodontically with a constant force of 20 g and on the side of the maxillary left first molar was used as control group. On the 4th, 10th and 17th days after experiment, 5 rats were euthanized, respectively. Histologic process was processed for immunohistochemical staining of MMP-9 and -13. Results: MMP-9 and -13 expressions were upregulated at day 4 after tooth movement. The expression of MMP-9 was not observed at days 7, 10 and 14, while the expression of MMP-13 was greatly increased at days 7 and 10. Conclusion: This study suggests that different characteristics of MMPs expression may contribute to the remodeling process of collagen fibers in the PDL during tooth movement.
Instanton interpolating current for $σ$--tetraquark
Hee-Jung Lee,N. I. Kochelev
Physics , 2006, DOI: 10.1016/j.physletb.2006.09.049
Abstract: We perform a QCD sum rule analysis for the light scalar meson $\sigma$ ($f_0(600)$) with a tetraquark current related to the instanton picture for QCD vacuum. We demonstrate that instanton current, including equal weights of scalar and pseudoscalar diquark-antidiquarks, leads to a strong cancelation between the contributions of high dimension operators in the operator product expansion (OPE). Furthermore, in the case of this current direct instanton contributions do not spoil the sum rules. Our calculation, obtained from the OPE up to dimension 10 operators, gives the mass of $\sigma$--meson around 780MeV.
High resolution impedance manometric findings in dysphagia of Huntington’s disease
Tae Hee Lee,Joon Seong Lee,Wan Jung Kim
World Journal of Gastroenterology , 2012, DOI: 10.3748/wjg.v18.i14.1695
Abstract: Conventional manometry presents significant challenges, especially in assessment of pharyngeal swallowing, because of the asymmetry and deglutitive movements of oropharyngeal structures. It only provides information about intraluminal pressure and thus it is difficult to study functional details of esophageal motility disorders. New technology of solid high resolution impedance manometry (HRIM), with 32 pressure sensors and 6 impedance sensors, is likely to provide better assessment of pharyngeal swallowing as well as more information about esophageal motility disorders. However, the clinical usefulness of application of HRIM in patients with oropharyngeal dysphagia or esophageal dysphagia is not known. We experienced a case of Huntington’s disease presenting with both oropharyngeal and esophageal dysphagia, in which HRIM revealed the mechanism of oropharyngeal dysphagia and provided comprehensive information about esophageal dysphagia.
The Efficacy and Safety of Succinylated Atelocollagen and Adenosine for the Treatment of Periorbital Wrinkles  [PDF]
Dong Jin Ryu, Jin Young Jung, Kee Yang Chung, Hwal Suh, Sang Ho Oh, Ju Hee Lee
Journal of Cosmetics, Dermatological Sciences and Applications (JCDSA) , 2013, DOI: 10.4236/jcdsa.2013.33036
Abstract:

The degradation of structural collagen contributes to the characteristic appearance of wrinkles. The anti-wrinkle effects of a variety of substances have been studied, but the potential anti-wrinkle effects of topical applications of collagen for periorbital wrinkles have not been investigated. To evaluate the effects of topical application of succinylated atelocollagen on periorbital wrinkles and to compare the results of treatment with adenosine, a clinical study on Korean participants was carried out. Each participant’s right or left periorbital area was treated with either a solution containing succinylated atelocollagen and adenosine or a solution containing only succinylated atelocollagen for two months. A placebo solution was applied to the opposite periorbital area of each patient’s face for two months. Based on objective and subjective measurements of clinical improvement, the assessment scores for treated sites were statistically significantly higher than scores for placebo sites after two months of treatment. Analysis of silicone casts of periorbital wrinkles demonstrated partial effects of succinylated atelocollagen on periorbital wrinkles. However, we did not observe any effects of adenosine on periorbital wrinkles. Succinylated atelocollagen may be an effective treatment option for periorbital wrinkles, but further studies including a longer treatment period and larger subject group are needed to verify these results.

Enhancement in Light Extraction Efficiency of GaN-Based Light-Emitting Diodes Using Double Dielectric Surface Passivation  [PDF]
Chung-Mo Yang, Dong-Seok Kim, Yun Soo Park, Jae-Hoon Lee, Yong Soo Lee, Jung-Hee Lee
Optics and Photonics Journal (OPJ) , 2012, DOI: 10.4236/opj.2012.23028
Abstract: SiO2Al2O3 double dielectric stack layer was deposited on the surface of the GaN-based light-emitting diode (LED). The double dielectric stack layer enhances both the electrical characteristics and the optical output power of the LED because the first Al2O3 layer plays a role of effectively passivating the p-GaN surface and the second lower index SiO2 layer increases the critical angle of the light emitted from the LED surface. In addition, the effect of the Fresnel reflection is also responsible for the enhancement in output power of the double dielectric passivated LED. The leakage current of the LED passivated with Al2O3 layer was -3.46 × 10-11 A at -5 V, at least two and three orders lower in magnitude compared to that passivated with SiO2 layer (-7.14 × 10-9 A) and that of non-passivated LED (-1.9 × 10-8 A), respectively, which indicates that the Al2O3 layer is very effective in passivating the exposed GaN surface after dry etch and hence reduces nonradiative recombination as well as reabsorption of the emitted light near the etched surface.
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