Publications by authors named "Cheol Yoon"

This study explores the potential application of lignin nanoparticles and chitosan-lignin nanoparticles (CLNs) as hydrophobic barrier coatings for paperboard. The lignin nanoparticles were initially prepared using a mixed solvent of ethanol and acetone. Their characteristics were examined via scanning electron microscopy (SEM) and dynamic light scattering, which revealed particle sizes in the range of 180-400 nm.

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This paper examines the design of antennas for Hi-pass type turnstiles needed to implement a subway free-pass system targeting transportation-disadvantaged individuals. The subway free-pass system allows individuals who have a free-pass card to approach the turnstile with the card on their person, which opens the gate automatically. This system, like the highway Hi-pass, allows users to pass through the subway gate without needing to scan a ticket.

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Treatment with highly active antiretroviral therapy (HAART) can prolong a patient's life-span by disrupting pivotal steps in the replication cycle of the human immunodeficiency virus-1 (HIV-1). However, drug resistance is emerging as a major problem worldwide due to the prolonged period of treatment undergone by HIV-1 patients. Since the approval of zidovudine in 1987, over thirty antiretroviral drugs have been categorized into the following six distinct classes based on their biological function and resistance profiles: (1) nucleoside analog reverse-transcriptase inhibitors; (2) non-nucleoside reverse transcriptase inhibitors; (3) integrase strand transferase inhibitors; (4) protease inhibitors; (5) fusion inhibitors; and (6) co-receptor antagonists.

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A facile new synthetic method for the preparation of a Type-A 1-arylnaphthalene lactone skeleton was developed and used to synthesise justicidin B and several derivatives. Key synthesis steps included Hauser-Kraus annulation of a phthalide intermediate and Suzuki-Miyaura cross coupling between a triflated naphthalene lactone intermediate and various potassium organotrifluoroborates. With two exceptions, the derivatives showed significant inhibitory effect on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in mouse macrophages.

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Background: Lung cancer has a high incidence worldwide, and most lung cancer-associated deaths are attributable to cancer metastasis. Although several medicinal properties of Meyer have been reported, the effect of ginsenosides Rk1 and Rg5 on epithelial-mesenchymal transition (EMT) stimulated by transforming growth factor beta 1 (TGF- β1) and self-renewal in A549 cells is relatively unknown.

Methods: We treated TGF-β1 or alternatively Rk1 and Rg5 in A549 cells.

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Purpose: The current study aimed to investigate the synergistic antitumor effect of combined treatment with 17-DMAG (HSP90 inhibitor) and NVP-BEZ235 (PI3K/mTOR dual inhibitor) on cisplatin-resistant human bladder cancer cells.

Materials And Methods: Human bladder cancer cells exhibiting cisplatin resistance (T24R2) were exposed to escalating doses of 17-DMAG (2.5-20 nM) with or without NVP-BEZ236 (0.

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4-Hexylresorcinol (4HR) is a small organic compound that is used as an additive antiseptic and antioxidant, but its molecular properties have not been clearly elucidated. The present study explored the cellular effects of 4HR on RAW 264.7 cells by immunoprecipitation high-performance liquid chromatography (IP-HPLC) using 216 antisera.

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Background: Coffee extract has been investigated by many authors, and many minor components of coffee are known, such as polyphenols, diterpenes (kahweol and cafestol), melanoidins, and trigonelline, to have anti-inflammatory, anti-oxidant, anti-angiogenic, anticancer, chemoprotective, and hepatoprotective effects. Therefore, it is necessary to know its pharmacological effect on hepatocytes which show the most active cellular regeneration in body.

Methods: In order to determine whether coffee extract has a beneficial effect on the liver, 20 C57BL/6J mice were intraperitoneally injected once with dialyzed coffee extract (DCE)-2.

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Objectives: Incomplete spinal cord injury (SCI) accounts for two-thirds of all SCIs in clinical practice. Preclinical research on the effect of sacral neuromodulation (SNM) on bladder function, however, has been focused only on animal models of complete SCI. We aimed to evaluate the effect of early SNM on bladder responses in a rat model of incomplete SCI.

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RAW 264.7 cells and HUVECs were compared to evaluate the effects of dialyzed coffee extract (DCE) and artificial coffee (AC). Immunoprecipitation high performance liquid chromatography (IP-HPLC) showed DCE-2.

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Background: The magnitude and rapidity of the tumor response to androgen deprivation is known to predict the durability of the therapy. We have investigated the predictive value of categorizing patients by the half-life of PSA under neoadjuvant androgen deprivation therapy in patients with biochemical recurrence after radical prostatectomy.

Methods: Medical records of 317 patients who received neoadjuvant androgen deprivation therapy before radical prostatectomy and developed biochemical recurrence were analyzed.

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Background: The association between lymphovascular invasion and lymphatic or hematogenous metastasis has been suspected, with conflicting evidence. We have investigated the association between the risk of biochemical recurrence and lymphovascular invasion in resection margin negative patients, as well as its association with lymph node metastasis.

Methods: One thousand six hundred thirty four patients who underwent radical prostatectomy from 2005 to 2014 were selected.

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Background: The pretreatment neutrophil-to-lymphocyte ratio has prognostic value after radical prostatectomy for treating localized prostate cancer. However, the use of postoperative neutrophil-to-lymphocyte ratio has not been evaluated in this population. We investigated the prognostic significance of early postoperative neutrophil-to-lymphocyte ratio after radical prostatectomy for prostate cancer.

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Purpose: In prostate cancer ductal adenocarcinoma is mixed with the usual acinar adenocarcinoma. However, to our knowledge whether the proportion of the ductal component affects oncologic outcomes is currently unknown. We investigated whether the proportion of the ductal component predicts oncologic outcomes in ductal adenocarcinoma.

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Background: Seminal vesicle invasion (SVI) is associated with adverse clinical outcomes in prostate cancer (PCa) patients. Despite its anatomical similarity and close proximity to the seminal vesicle, the prognostic significance of vas deferens invasion (VDI) by PCa has not been elucidated. For these reasons, we investigated the impact of VDI on the oncological outcome of pT3b PCa in association with SVI.

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Background: Current National Comprehensive Cancer Network guidelines recommend postoperative radiation therapy based only on adverse pathologic findings (APFs), irrespective of preoperative risk group. We assessed whether a model incorporating both the preoperative risk group and APFs could predict long-term oncologic outcomes better than a model based on APFs alone.

Methods: We retrospectively reviewed 4,404 men who underwent radical prostatectomy (RP) at our institution between 1992 and 2014.

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Introduction: Positive surgical margins (PSM) detected in the radical prostatectomy specimen increase the risk of biochemical recurrence (BCR). Still, with formidable number of patients never experiencing BCR in their life, the reason for this inconsistency has been attributed to the artifacts and to the spontaneous regression of micrometastatic site. To investigate the origin of margin positive cancers, we have looked into the influence of extraprostatic extension location on the resection margin positive site and its implications on BCR risk.

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Introduction And Objectives: Computed tomography (CT) is one of the most commonly used diagnostic modalities for urinary stone disease. In this study we developed a CT and clinical parameter-based prediction model for shockwave lithotripsy (SWL) outcome in proximal ureteral stones.

Materials And Methods: Data from 223 patients with single proximal ureteral stones treated with SWL between January 2009 and January 2015 were reviewed retrospectively.

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We report herein the discovery and optimization of 3-amino-1,5-dihydro-4H-pyrazolopyridin-4-one TYK2 inhibitors. High-throughput screening against TYK2 and JAK1-3 provided aminoindazole derivative 1 as a hit compound. Scaffold hopping of the aminoindazole core led to the discovery of 3-amino-1,5-dihydro-4H-pyrazolopyridin-4-one derivative 3 as a novel chemotype of TYK2 inhibitors.

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We recently encountered an extremely rare case of spontaneous perirenal hemorrhage in a 34-year-old man. He initially had undergone radical nephrectomy owing to suspicion of renal cell carcinoma. The final diagnosis was extraskeletal Ewing sarcoma.

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Objectives: To investigate the role of EphA2 in malignant cellular behavior in renal cell carcinoma (RCC) cells and whether FAK/RhoA signaling can act as downstream effectors of EphA2 on RCC cells.

Methods: Expression of EphA2 protein in non-metastatic RCC (Caki-2 and A498), metastatic RCC cells (Caki-1 and ACHN), HEK-293 cells and prostate cancer cells (PC-3 and DU-145; positive controls of EphA2 expression) was evaluated by Western blot. Changes in mRNA or protein expression of EphA2, FAK or membrane-bound RhoA following EphA2, FAK or RhoA small interfering RNA (siRNA) transfection were determined by reverse transcription polymerase chain reaction or Western blot.

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Introduction: Fibrotic scar formation is a main cause of recurrent urethral stricture after initial management with direct vision internal urethrotomy (DVIU). In the present study, we devised a new technique of combined the transurethral resection of fibrotic scar tissue and temporary urethral stenting, using a thermo-expandable urethral stent (Memokath(TM) 044TW) in patients with anterior urethral stricture.

Materials And Methods: As a first step, multiple incisions were made around stricture site with cold-utting knife and Collins knife electrode to release a stricture band.

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Purpose: This study was performed to investigate the discomfort reported by patients taking phosphodiesterase type 5 inhibitors (PDE5Is) in clinical practice.

Materials And Methods: From September 2011 to March 2012, we surveyed patients who were prescribed PDE5Is for erectile dysfunction (ED). The questionnaire elicited information concerning: patient characteristics, medication counseling received and inconveniences experienced in hospitals and at pharmacies, effects of PDE5Is, and the separation of the prescribing and the dispensing of PDE5Is.

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According to recent studies, mTOR (mammalian target of rapamycin) inhibitor and tyrosine kinase inhibitor (TKI) can be used as combinational agents to enhance the antitumor effect or overcome resistance to one of the agents. In the present study, we investigated the synergistic interaction between NVP-BEZ235, a PI3K (phosphoinositide 3-kinase)/mTOR dual inhibitor, and sunitinib, a TKI, in castration-resistant prostate cancer (CRPC) cells with docetaxel resistance. Prostate cancer cells with different sensitivities to hormones and docetaxel levels were exposed to escalating doses of NVP-BEZ235 alone and in combination with sunitinib.

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The PI3K/Akt/mTOR pathway is a prototypic survival pathway and constitutively activated in many malignant conditions. Moreover, activation of the PI3K/Akt/mTOR pathway confers resistance to various cancer therapies and is often associated with a poor prognosis. In this study, we explored the antitumor effect of NVP-BEZ235, a dual PI3K/mTOR inhibitor in cisplatin-resistant human bladder cancer cells and its synergistic interaction with cisplatin.

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