Kyonggi University

About: Kyonggi University is a education organization based out in Suwon, South Korea. It is known for research contribution in the topics: Catalysis & Dielectric. The organization has 1946 authors who have published 4404 publications receiving 64791 citations.

Synthesis and up-conversion luminescence of Lu_3Al_5O_12:Yb^3+,Er^3+

Abstract: Under infrared radiation, the upconversion emission spectra of Lu3-x-yYbxEryAl5O12 consisted of green and red emission bands that were attributed to the 2H11/2/4S3/2 → 4I15/2 and 4F9/2 → 4I15/2 transitions of the Er3+ ions, respectively; these transitions occurred by means of an energy transfer (ET) process from Yb3+ to Er3+. The intensity of the red emission was higher than that of the green emission, thereby resulting in CIE chromaticity coordinates that lay within the yellow region. The emission ratio of red to green exhibited a strong dependence on the ratio of Yb3+/Er3+. These behaviors were attributed to cross relaxation between the Er3+ ions, multiphoton relaxation, and the ET process.

Observations of Forsythia koreana methanol extract on mast cell-mediated allergic reactions in experimental models

Abstract: To explore effects of Forsythia koreana methanol extract (FKME) on mast cell-mediated allergic and inflammatory properties, the effect of FKME was evaluated on compound 48/80-induced systemic anaphylaxis, ear swelling, and anti-dinitrophenyl (DNP) immunoglobulin E (IgE)-induced passive cutaneous anaphylaxis (PCA). In addition, the effect of FKME was investigated on the histamine release from rat peritoneal mast cells (RPMCs) stimulated by compound 48/80, which promotes histamine release. The human mast cell line HMC-1 was stimulated by phorbol 12-myristate 13-acetate plus calcium ionophore A23187. Activated HMC-1 can produce several proinflammatory and chemotactic cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6, and IL-8. Cytokine levels in the culture supernatant were measured by an enzyme-linked immunosorbent assay. Cytotoxicity by FKME was determined by a 3-(4,5-dimethylthiazol-2-yl)-diphenyl-tetrazolium bromide (MTT) assay. FKME inhibited compound 48/80-induced systemic anaphylactic shock and ear swelling in mice. When 1 g/kg FKME was pretreated or posttreated with mice, compound 48/80-induced mice morality was 50 and 66.7%, respectively. One gram per kilogram of FKME pretreatment inhibited ear-swelling responses derived from compound 48/80 by 29.75%. A PCA reaction was inhibited by 17.9%. In an in vitro model, FKME (1 mg/ml) inhibited histamine release from the RPMCs by 13.8% and TNF-α, IL-6, and IL-8 production from HMC-1 cells by 71.16% (P < 0.001), 86.72% (P < 0.001), and 44.6%, respectively. However, FKME had no cytotoxic effects on cell viability. In conclusion, FKME inhibited not only systemic anaphylaxis and ear swelling induced by compound 48/80 but also inhibited a PCA reaction induced by anti-DNP IgE in vivo. Treatment with FKME showed significant inhibitory effects on histamine, TNF-α, IL-6, and IL-8 release from mast cells.

Alteration of Autonomic Function in Female Urinary Incontinence

Abstract: PURPOSE Stress urinary incontinence (SUI) and urge urinary incontinence (UUI) have different mechanisms of action. We believe that alteration of autonomic nervous system (ANS) activity may contribute to UUI because the lower urinary tract is regulated through the sympathetic and parasympathetic nervous systems. Heart rate variability (HRV) allows measurement of autonomic nervous function, therefore we measured and compared HRV parameters in women with urinary incontinence. METHODS From March 2008 to March 2010, we evaluated all patients who visited 2 university hospitals for treatment of urinary incontinence. Theywere performed 3-day voiding diary, urodynamic study, physical examination and routine laboratory examination. We excluded subjects who had diabetes, cardiovascular problems, or other condition that affect ANS. Patients with mixed urinary incontinence (MUI) were also excluded. Finally 47 women with SUI (group 1) and 29 women with UUI (group 2) were enrolled according to their symptoms and voiding diary. We compared their HRV parameters. And excluding 11 patients who had detrusor underactivity, we divided them again into group A, 53 women without detrusor overactivity (DO) and group B, 12 women with DO. We compared HRV parameters between DO and non-DO group. RESULTS Older women had a higher incidence of UUI and DO. In HRV parameters, only the ratio of low frequency (LF) and high frequency (HF) was significantly higher in group 2 than group 1 (3.5±3.6 vs. 1.6±1.1, P<0.05). Also group A had higher mean LF/HF ratio than group B (4.3±3.8 vs. 1.9±1.9, P<0.05). CONCLUSIONS Increased LF/HF values indicate relative sympathetic hyperactivity over parasympathetic activity. Changes in ANS activity could indicate the presence of UUI and potentially DO.

Multimedia recommendation using Word2Vec-based social relationship mining

Abstract: This study proposes the multimedia recommendation method using Word2Vec-based social relationship mining. This is to analyze users with a similar tendency on the basis of the keywords related to multimedia content and sentiment words of comments, to build a trust relationship, and to recommend multimedia. In order to solve the problem of data sparsity, metadata of multimedia content are collected and then are clustered by genre. User’s evaluate a preference for multimedia content. With the use of evaluation data, the attributes preferred by users are predicted. In terms of propensities, the sentiment words in users comments are classified by SVM on the basis of sentiment dictionary. The classified sentiment words are presented in vector with the use of Word2Vec. In terms of the vector of sentiment words, the dynamic relationship between users of words in the same preference by the similarity using the distance scale. It helps to build a trust relationship between users with preferences that can change with a lapse of time. Accordingly, multimedia content are recommended to users with a similar tendency. In terms of performance evaluation, F-measure is compared with the uses of precision and recall for a recommendation. As the result of evaluation, the social relationship mining method is evaluated to be better than explicit and implicit recommendation methods. With the proposed method, it is possible to search with metadata of content and make a intelligent recommendation explicitly and implicitly according to user’s tendency.