122,079 research outputs found
Han Gyeol Kim
No full text학위논문(석사)아주대학교 일반대학원 :의학계열,2012. 8I. INTRODUCTION 1
II. MATERIALS AND METHODS 2
A. Study subjects 3
B. Questionnaire 3
C. Genotyping 3
D. Statistical analysis 4
III. RESULTS 5
IV. DISCUSSION 9
V. CONCLUSION 12
REFERENCES 13
국문요약 16MasterBackground: G-protein beta3 subunit (GNB3) C825T polymorphism alters intracellular signal transduction, which may lead to motor or sensory abnormalities of the gastrointestinal tract. The aim of the present study was to evaluate the association of the GNB3 C825T polymorphism with susceptibility to overlap syndrome of functional dyspepsia (FD) and irritable bowel syndrome (IBS) in a Korean population.
Methods: One hundred sixty-seven patients with FD alone, 60 patients with IBS alone, 85 patients with the overlap of FD and IBS, and 434 asymptomatic healthy subjects participated in the study. Genotyping for GNB3 C825T polymorphism was performed using their blood samples.
Results: No association of genotype in subjects with FD alone, IBS alone or overlap phenotype compared to that in controls was detected. The frequency of GNB3 C825T CT and TT genotypes relative to the CC genotype for the phenotypes of FD alone, IBS alone, and the coexistence of FD and IBS did not significantly differ. Comparison of the TT genotype with the CC/CT genotype showed no significant association for each phenotype group.
Conclusions: There is no apparent association of the GNB3 C825T polymorphism with the susceptibility to FD, IBS or the overlap of FD and IBS. A larger-scale study and further investigation on other candidate genes are required
Novel sol–gel preparation of (PO)–(CaO)–(NaO)–(TiO) bioresorbable glasses (X = 0.05, 0.1, and 0.15)
No full textQuaternary phosphate-based glasses in the PO–CaO–NaO–TiO system with a fixed PO and CaO content of 40 and 25 mol% respectively have been successfully synthesised via sol–gel method and bulk, transparent samples were obtained. The structure, elemental proportion, and thermal properties of stabilised sol–gel glasses have been characterised using X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), P nuclear magnetic resonance (P NMR), titanium K-edge X-ray absorption near-edge structure (XANES), fourier transform infrared (FTIR) spectroscopy, and differential thermal analysis (DTA). The XRD results confirmed the amorphous nature for all stabilized sol–gel derived glasses. The EDX result shows the relatively low loss of phosphorus during the sol–gel process and Ti K-edge XANES confirmed titanium in the glass structure is in mainly six-fold coordination environment. The P NMR and FTIR results revealed that the glass structure consist of mainly Q and Q phosphate units and the Ti cation was acting as a cross-linking between phosphate units. In addition DTA results confirmed a decrease in the glass transition and crystallisation temperature with increasing NaO content. Ion release studies also demonstrated a decrease in degradation rates with increasing TiO content therefore supporting the use of these glasses for biomedical applications that require a degree of control over glass degradation. These sol–gel glasses also offer the potential to incorporate proactive molecules for drug delivery application due to the low synthesis temperature employed
Sol-gel derived hydroxyapatite, fluorhydroxyapatite and fluorapatite coatings for titanium implants
No full textCurrently, most titanium implant coatings are made using hydroxyapatite and a
plasma-spraying technique. There are however limitations associated with the
plasma-spraying process including; poor adherence, high porosity and cost. An
alternative - the sol-gel technique offers many potential advantages but is
currently lacking research data for this application.
Hydroxyapatite (HA), fluorhydroxyapatite (FHA) and fluorapatite (FA) have
been synthesised by a sol-gel method. Calcium nitrate and triethyl phosphite
were used as precursors under an ethanol-water based solution. Different
amounts of ammonium fluoride (NH4F) were incorporated for the preparation of
the FHA and FA sol-gels. Optimisation and characterisation of the sol-gels was
carried out using, X-ray Diffraction (XRD), High Temperature X-Ray Diffraction
(HTXRD), Fourier Transform Infrared Analysis (FTIR) and Differential Thermal
Analysis (DTA).
Rheology and hydrophilicity of the sol-gels showed that increasing fluoride ion
substitution caused an increase in viscosity and contact angle.
The dissolution (Ca2+ and PO4
3-rates) rates of the fluoride-substituted powders
from the sol-gels were considerably lower than that of HA and all rates could be
decreased by increasing the sintering temperature. This suggests the
possibility of tailoring the solubility of any coatings made from the sol-gels
through fluoride ion substitution and increased sintering temperature.
A spin coating protocol has been established for coating the sol-gels onto
titanium. Increasing the coating speed decreased the porosity and thickness of
the coatings. Bond strengths to titanium were investigated. Fluoride substitution
and sintering temperature were shown to be important factors. Cellular proliferation studies revealed that increasing the level of fluoride
substitution in the apatite structure significantly increased the biocompatibility
of the material.
The sol-gel technique may be an alternative to plasma spraying for coating
titanium implants. Furthermore it may also be suitable for producing HA, FHA
and FA as bone grafting materials
Fabrication of high temperature piezoelectric ceramics by sol gel method
No full textThis research covers the fabrication of piezoelectric ceramics using a sol gel
method. Commercial high temperature transducers are typically fabricated by a
milled oxide method. The sol gel method presented here produced purer samples that
can be prepared at lower temperatures than conventional milled oxide preparations.
The performance of the samples as piezoelectric transducers was also investigated,
with the samples produced by sol gel method exceeding the piezoelectric response of
the commercial samples
Choong Han Kim
No full textBlack and white head shot photograph of Choong Han Kim, Assistant Professor in Library Science, 1965-1967.https://thekeep.eiu.edu/archives_faculty_il/1090/thumbnail.jp
Crowding and confinement effects on enzyme stability in mesoporous silicas
No full textTo understand the protein functions within a cell, where proteins exist in an extremely crowded and confined state, various modeling and experimental methods have been proposed. Here, we propose a new experimental approach to modulate the macromolecular crowding and/or confinement effects by using mesoporous silicas with two different pore structures. SBA-15 and MSU-F with linear and mesocellular pore structures, respectively, were used to adsorb a model enzyme, glucose oxidase (GOx), in various concentrations ranging from 3 to 430 mg ml(-1). The concentration of adsorbed GOx in the mesopores, representing the degree of crowding, showed a good correlation with thermal enzyme stability. Interestingly, the increase of thermal stability as a function of macromolecular crowding showed different correlations depending on the pore structure of mesoporous silicas. It represents that combination of crowding and confinement effects can promote different microenvironments for enzyme molecules, while mesoporous silicas can impose controlled crowding and confinement effects on enzymes due to their uniform and tunable pore structures. It is anticipated that this new and simple approach can provide a tool to elucidate crowding and confinement effects on the protein functions, including its stability in vivo, because the mesopore environments could mimic the real macromolecular cell system under crowding.
Genome-scale knockout simulation and clustering analysis of drug-resistant breast cancer cells reveal drug sensitization targets
No full textAnticancer chemotherapy is essential for cancer treatment, yet resistance remains a major challenge. Metabolic reprogramming is a key phenotype in drug resistance. Here, we developed a computational framework to predict metabolic gene targets that revert the metabolic state of resistant cells to that of sensitive cells, restoring drug sensitivity. It performs single-gene knockout simulations in genome-scale metabolic models, clusters resulting flux profiles via uniform manifold approximation and projection with k-means clustering, and identifies knockouts shifting flux patterns toward those of sensitive cells as drug sensitization targets. Applied to doxorubicin- and paclitaxel-resistant MCF7 breast cancer cells, we identified GOT1 for doxorubicin-resistant MCF7, GPI for paclitaxel-resistant MCF7, and SLC1A5 as a common target. Treating resistant cells with small-molecule inhibitors restored their drug sensitivity. The framework was also effective in drug-resistant triple-negative breast cancer cells. Overall, it provides an intuitive, cost-efficient strategy for predicting drug sensitization targets with potential applications across various cancers and metabolic diseases
Supplemental_material_v0.1 – Supplemental material for Bioprinting of three-dimensional dentin–pulp complex with local differentiation of human dental pulp stem cells
No full textSupplemental material, Supplemental_material_v0.1 for Bioprinting of three-dimensional dentin–pulp complex with local differentiation of human dental pulp stem cells by Jonghyeuk Han, Da Sol Kim, Ho Jang, Hyung-Ryong Kim and Hyun-Wook Kang in Journal of Tissue Engineering</p
Sol-gel transition behavior of biodegradable three-arm and four-arm star-shaped PLGA-PEG block copolymer aqueous solution
No full textTwo types of temperature-sensitive biodegradable three-arm and four-arm star-shaped poly(DL-lactic acid-co-glycolic acid-b-ethylene glycol) (3-arm and 4-arm PLGA-PEG) were successfully synthesized via the coupling reaction of 3-arm and 4-arm PLGA and alpha-monocarboxyl-omega-monomethoxypoly(ethylene glycol) (CMPEG), In dilute aqueous solutions, star PLGA-PEGs showed the temperature- and concentration-dependent formation and aggregation of micelles over specific concentration and specific temperature. With increasing the molecular weight and the relative hydrophobicity of hydrophobic PLGA block, critical micelle temperature (CMT) decreased, Aqueous solution of 4-arm PLGA-PEG started to form micelles at lower, temperature and showed sharper temperature-dependent growth in micelle size. These results are due to the enhanced hydrophobicity of PLGA block. On the other hand, at high concentration, two types of 3-arm and 4-arm PLGA-PEG showed sol-gel-sol transition behavior as the temperature was increased. The 3-arm and 4-arm PLGA-PEG Showed sol-gel transition at higher polymer concentrations (above 24 wt %) than the PEG-PLGA-PEG triblock copolymer. As the molecular weight and the relative hydrophobicity of PLGA block increased, the critical gel concentration (CGC) decreased. (c) 2005 Wiley Periodicals, Inc
Chinese literary works translated into Baba Malay: a bibliographical study
No full textAnalyses 68 unique titles of Baba translated works published between 1889 and 1950. The titles are held in the libraries of the University of Malaya (UM), Science University Malaysia (USM), National University of Malaysia (UKM), the Dewan Bahasa dan Pustaka (DBP), National University of Singapore (NUS), National Library of Singapore (NLS) and the British Library (BL). The results reveal three periods of active publication of Baba translated works. A total of 18 works were translated before World War I, followed by 10 just after the war, 39 titles were published before the break of the World War II and 1 was identified in 1950. There were 103 persons involved in the 68 translated works, some of whom are responsible for more than one title. The most prominent translators were Chan Kim Boon, Wan Boon Seng, Seow Chin San and Lee Seng Poh. Some of the translators were also be editors, illustrators or editors. There were 31 publishers and 21 printing presses involved, all were located in Singapore. The most active publishers were Wan Boon Seng, Kim Seck Chy Press and Nanyang Romanised Malay Book Co. The translated works mainly cover historical classical Chinese stories, chivalrous stories, romances, folklore and legends. The titles were priced between 10 cents to 2 dollars in Straits currency. The University of Malaya Library held the largest number of unique title (62) out of which 15 were unique titles
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