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"Park, Yuri"
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Carbon Dots as an Effective Fluorescent Sensing Platform for Metal Ion Detection
2019
Fluorescent carbon dots (CDs) including carbon quantum dots (CQDs) and graphene quantum dots (GQDs) have drawn great interest because of their low cost and low toxicity, and they represent a new class of carbon materials prepared by simple synthetic routes. In particular, the optical properties of CDs can be easily tuned by the surface passivation of the organic layer and functionalization of the CDs. Based on the advantages of these carbon materials, CQDs and GQDs have been applied in various fields as nanoplatforms for sensing, imaging, and delivery. In this review, we discuss several synthetic methods for preparing CQDs and GQDs, as well as their physical properties, and further discuss the progress in CD research with an emphasis on their application in heavy metal sensing.
Journal Article
Interferon Signaling in the Endometrium and in Endometriosis
2022
Endometriosis is an estrogen-dependent inflammatory disease that develops in reproductive-aged women who experience pelvic pain and infertility. Even though endometriosis is not a new disease, its molecular etiology has not been clearly elucidated. Defects in the immune system might be one of the factors that promote endometriosis progression. For example, elevated levels of proinflammatory cytokines are associated with endometriosis. Interferon is one of the cytokines that is elevated in endometriotic tissues compared with normal endometrium. Therefore, high interferon levels play a crucial role in endometriosis progression. In addition to endometriosis, however, interferon has a critical role in endometrial function, particularly in the initiation and maintenance of pregnancy. Therefore, this review describes the double-edged sword of interferon signaling in normal endometrial function versus endometriosis progression and also discusses interferon targeting as a new nonhormonal therapy for endometriosis. This approach may increase the efficacy of endometriosis treatment and reduce the adverse effects associated with current hormonal therapy for this disease.
Journal Article
Exploring the Impact of COVID-19 on Job Satisfaction Trends: A Text Mining Analysis of Employee Reviews Using the DMR Topic Model
by
Kim, Jaeyun
,
Park, Yuri
,
Lee, Daeho
in
Computational linguistics
,
Corporate culture
,
Corporate growth
2025
Job satisfaction is a critical determinant in talent acquisition and corporate value enhancement. The COVID-19 pandemic has triggered a significant increase in online-based non-face-to-face services and consumption, leading to sustained growth in ICT industry job demand. Given the ICT sector’s heavy reliance on human capital and its growing workforce demands, understanding the evolving factors of job satisfaction in this sector has become increasingly crucial. This study analyzed job satisfaction factors derived from employee reviews on an online job review platform using the Dirichlet Multinomial Regression (DMR) topic model, examining temporal changes in these factors before and after the COVID-19 pandemic. As a result, 25 distinct job satisfaction-related topics were identified, and their temporal distribution patterns were categorized into three trajectories: ascending, descending, and stable. Topics exhibiting ascending patterns included work–life balance, organizational systems, corporate culture, employee benefits, work environment, and software development practices. Conversely, factors demonstrating descending patterns encompassed annual compensation, task characteristics, supervisory relationships, employee treatment, commuting conditions, work-related stress, and welfare programs. The remaining topics maintained relatively stable patterns throughout the observation period. These findings contribute to both academic literature and industry practice by elucidating the evolutionary trends in job satisfaction determinants during the COVID-19 pandemic, thereby facilitating more informed strategic human resource management decisions in the ICT sector.
Journal Article
Oleuropein suppresses endometriosis progression and improves the fertility of mice with endometriosis
2022
Background
Endometriosis is an estrogen-dependent inflammatory reproductive disease. Therefore, systematic estrogen depletion and anti-inflammatory drugs are the current treatment for endometriosis. However, current endometriosis treatments have low efficacy and cause adverse effects in endometriosis patients. Consequently, alternative endometriosis treatments targeting endometriosis-specific factors are in demand. In this context, ERβ was selected as a druggable target for endometriosis due to its critical role in progression. Therefore, selective targeting of ERβ without inhibiting ERα activity would be a new paradigm for endometriosis treatment to overcome the low efficacy and adverse effects of hormonal endometriosis therapy.
Methods
Cell-based ERβ and ERα activity assay systems were employed to define a selective ERβ-inhibiting chemical product from a library of natural products. A surgically induced endometriosis mouse model was used to determine whether an ERβ inhibitory drug suppressed endometriosis progression. Mice with endometriosis were randomly separated and then orally treated with vehicle or 25 mg/kg oleuropein (once a day for 21 days), an ERβ inhibitory drug. The volume of endometriotic lesions or luciferase activity of endometriotic lesions was examined to define the growth of ectopic lesions in mice with endometriosis. The metabolite and levels of metabolic enzymes of the liver and kidney were determined in the serum of female mice treated with vehicle and oleuropein (25 mg/kg, once a day for 21 days) to define the toxicity of oleuropein. The in vitro decidualization assay was conducted with normal human endometrial stromal cells and endometriotic stromal cells to determine whether oleuropein overcomes decidualization in endometriosis patients. The pregnancy rate and pup numbers of C57BL/6 J female mice with endometriosis treated with vehicle or oleuropein (n = 10/group) were determined after mating with male mice. The cytokine profile in endometriotic lesions treated with vehicle and oleuropein (25 mg/kg) was determined with a Mouse Cytokine Array Kit.
Results
Among natural products, oleuropein selectively inhibited ERβ but not ERα activity in vitro. Oleuropein treatment inhibited the nuclear localization of ERβ in human endometrial cells upon estradiol treatment. Oleuropein (25 mg/kg) treatment suppressed the growth of mouse (6.6-fold) and human (sixfold) ectopic lesions in mice with endometriosis compared to the vehicle by inhibiting proliferation and activating apoptosis in endometriotic lesions. Oleuropein treatment did not cause reproductive toxicity in female mice. Additionally, mice with endometriosis subjected to oleuropein treatment had a higher pregnancy rate (100%) than vehicle-treated mice (70%). Furthermore, oleuropein treatment partially recovered the decidualization impact of human endometriotic stromal cells from endometriotic lesions compared to the vehicle. Oleuropein-treated mice with endometriosis exhibited significantly lower levels of cytokines directly regulated by ERβ in ectopic lesions than vehicle-treated mice, illustrating the improvement in the hyperinflammatory state of mice with endometriosis.
Conclusions
Oleuropein is a promising and novel nutraceutical product for nonhormonal therapy of endometriosis because it selectively inhibits ERβ, but not ERα, to suppress endometriosis progression and improve the fertility of mice with endometriosis.
Journal Article
Quantification of an Antibody-Conjugated Drug in Fat Plasma by an Affinity Capture LC-MS/MS Method for a Novel Prenyl Transferase-Mediated Site-Specific Antibody–Drug Conjugate
2020
The novel prenyl transferase-mediated, site-specific, antibody–drug conjugate LCB14-0110 is comprised of a proprietary beta-glucuronide linker and a payload (Monomethyl auristatin F, MMAF, an inhibitor for tubulin polymerization) attached to human epidermal growth factor receptor 2 (HER2)-targeting trastuzumab. A LC-MS/MS method was developed to quantify the antibody-conjugated drug (acDrug) for in vitro linker stability and preclinical pharmacokinetic studies. The method consisted of affinity capture, enzymatic cleavage of acDrug, and LC-MS/MS analysis in the positive ion mode. A quadratic regression (weighted 1/concentration2), with the equation y = ax2 + bx + c, was used to fit calibration curves over the concentration range of 19.17~958.67 ng/mL for acDrug. The qualification run met the acceptance criteria of ±25% accuracy and precision values for quality control (QC) samples. The overall recovery was 42.61%. The dilution integrity was for a series of 5-fold dilutions with accuracy and precision values ranging within ±25%. The stability results indicated that acDrug was stable at all stability test conditions (short-term: 1 day, long-term: 10 months, Freeze/Thaw (F/T): 3 cycles). This qualified method was successfully applied to in vitro linker stability and pharmacokinetic case studies of acDrug in rats.
Journal Article
Catalytic Hydrodechlorination of 4-Chlorophenol by Palladium-Based Catalyst Supported on Alumina and Graphene Materials
2023
Hydrodechlorination (HDC) is a reaction that involves the use of hydrogen to cleave the C−Cl bond in chlorinated organic compounds such as chlorophenols and chlorobenzenes, thus reducing their toxicity. In this study, a palladium (Pd) catalyst, which is widely used for HDC due to its advantageous physical and chemical properties, was immobilized on alumina (Pd/Al) and graphene-based materials (graphene oxide and reduced graphene oxide; Pd/GO and Pd/rGO, respectively) to induce the HDC of 4-chlorophenol (4-CP). The effects of the catalyst dosage, initial 4-CP concentration, and pH on 4-CP removal were evaluated. We observed that 4-CP was removed very rapidly when the HDC reaction was induced by Pd/GO and Pd/rGO. The granulation of Pd/rGO using sand was also investigated as a way to facilitate the separation of the catalyst from the treated aqueous solution after use, which is to improve practicality and effectiveness of the use of Pd catalysts with graphene-based support materials in an HDC system. The granulated catalyst (Pd/rGOSC) was employed in a column to induce HDC in a continuous flow reaction, leading to the successful removal of most 4-CP after 48 h. The reaction mechanisms were also determined based on the oxidation state of Pd, which was observed using X-ray photoelectron spectroscopy. Based on the results as a whole, the proposed granulated catalyst has the potential to greatly enhance the practical applicability of HDC for water purification.
Journal Article
Evaluation of In Vivo Prepared Albumin-Drug Conjugate Using Immunoprecipitation Linked LC-MS Assay and Its Application to Mouse Pharmacokinetic Study
by
Hwang, Sangsoo
,
Lee, Jiyu
,
Park, Yuri
in
Albumin
,
albumin-drug conjugate
,
Albumins - chemistry
2023
There have been many attempts in pharmaceutical industries and academia to improve the pharmacokinetic characteristics of anti-tumor small-molecule drugs by conjugating them with large molecules, such as monoclonal antibodies, called ADCs. In this context, albumin, one of the most abundant proteins in the blood, has also been proposed as a large molecule to be conjugated with anti-cancer small-molecule drugs. The half-life of albumin is 3 weeks in humans, and its distribution to tumors is higher than in normal tissues. However, few studies have been conducted for the in vivo prepared albumin-drug conjugates, possibly due to the lack of robust bioanalytical methods, which are critical for evaluating the ADME/PK properties of in vivo prepared albumin-drug conjugates. In this study, we developed a bioanalytical method of the albumin-conjugated MAC glucuronide phenol linked SN-38 ((2S,3S,4S,5R,6S)-6-(4-(((S)-4,11-diethyl-4-hydroxy-3,14-dioxo-3,4,12,14-tetrahydro-1H-pyrano [3′,4′:6,7] indolizino [1,2-b] quinolin-9-yl)oxy)methyl)(2 (methylsulfonyl)ethyl)carbamoyl)oxy)methyl)-2-(2-(3-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)-N-methylpropanamido)acetamido)phenoxy)-3,4,5-trihydroxytetra-hydro-2H-pyran-2-carboxylic acid) as a proof-of-concept. This method is based on immunoprecipitation using magnetic beads and the quantification of albumin-conjugated drug concentration using LC-qTOF/MS in mouse plasma. Finally, the developed method was applied to the in vivo intravenous (IV) mouse pharmacokinetic study of MAC glucuronide phenol-linked SN-38.
Journal Article
Investigation of In Vitro and In Vivo Metabolism of α-Amanitin in Rats Using Liquid Chromatography-Quadrupole Time-of-Flight Mass Spectrometric Method
2022
The purpose of this study is to investigate the difference of in vitro–in vivo correlation of α-amanitin from clearance perspectives as well as to explore the possibility of extra-hepatic metabolism of α-amanitin. First, a liquid chromatography-quadrupole-time-of-flight-mass spectrometric (LC-qTOF-MS) method for α-amanitin in rat plasma was developed and applied to evaluate the in vitro liver microsomal metabolic stability using rat and human liver microsomes and the pharmacokinetics of α-amanitin in rat. The predicted hepatic clearance of α-amanitin in rat liver microsomes was quite low (5.05 mL/min/kg), whereas its in vivo clearance in rat (14.0 mL/min/kg) was close to the borderline between low and moderate clearance. To find out the difference between in vitro and in vivo metabolism, in vitro and in vivo metabolite identification was also conducted. No significant metabolites were identified from the in vivo rat plasma and the major circulating entity in rat plasma was α-amanitin itself. No reactive metabolites such as GSH-adducts were detected either. A glucuronide metabolite was newly identified from the in vitro liver microsomes samples with a trace level. A semi-mass balance study was also conducted to understand the in vivo elimination pathway of α-amanitin and it showed that most α-amanitin was mainly eliminated in urine as intact which implies some unknown transporters in kidney might play a role in the elimination of α-amanitin in rat in vivo. Further studies with transporters in the kidney would be warranted to figure out the in vivo clearance mechanism of α-amanitin.
Journal Article
Aminated Covalent Organic Polymers for Anionic Dye Adsorption in Aqueous Systems
2023
Aminated covalent organic polymer (ACOP) was synthesized through a catalyst-free Schiff base reaction involving terephthalaldehyde and melamine, and the prepared ACOP was used for the adsorption of anionic dyes. The prepared ACOP possessed a high specific surface area (582.07 m2/g) with an average pore size of 88.71 Å. Its point of zero charge was determined as pH 8.26. Anionic dye molecules, methyl orange (MO) and orange G (OG), were used to evaluate the dye adsorption efficiency of the prepared ACOP, and it was found that they were adsorbed rapidly on ACOP within 1 min. The maximum adsorption capacities (qm) of the prepared ACOP for MO and OG were 351.9 and 227.9 mg/g, respectively. Furthermore, the results of dye adsorption as a function of the initial pH and presence/absence of cationic dye (methylene blue; MB) revealed that dye adsorption on ACOP proceeded through charge–charge and π–π interactions. The presence of MB along with MO and OG enhanced the dye adsorption capacity because of the synergistic effect of the positively charged quaternized nitrogen atoms in the prepared ACOP. The dye adsorption mechanism was further investigated using Fourier transform infrared (FT-IR) analysis and X-ray photoelectron spectrometry (XPS). The ACOP adsorbent prepared herein using a facile catalyst-free reaction offers rapid adsorption with a high adsorption efficiency over a wide pH range and in the presence of cationic dye. For these reasons, it can be used for environmental remediation, especially in aqueous systems.
Journal Article
Quantitative Analysis of Daporinad (FK866) and Its In Vitro and In Vivo Metabolite Identification Using Liquid Chromatography-Quadrupole-Time-of-Flight Mass Spectrometry
2022
Daporinad (FK866) is one of the highly specific inhibitors of nicotinamide phosphoribosyl transferase (NAMPT) and known to have its unique mechanism of action that induces the tumor cell apoptosis. In this study, a simple and sensitive liquid chromatography–quadrupole-time-of-flight–mass spectrometric (LC-qTOF-MS) assay has been developed for the evaluation of drug metabolism and pharmacokinetics (DMPK) properties of Daporinad in mice. A simple protein precipitation method using acetonitrile (ACN) was used for the sample preparation and the pre-treated samples were separated by a C18 column. The calibration curve was evaluated in the range of 1.02~2220 ng/mL and the quadratic regression (weighted 1/concentration2) was used for the best fit of the curve with a correlation coefficient ≥ 0.99. The qualification run met the acceptance criteria of ±25% accuracy and precision values for QC samples. The dilution integrity was verified for 5, 10 and 30-fold dilution and the accuracy and precision of the dilution QC samples were also satisfactory within ±25% of the nominal values. The stability results indicated that Daporinad was stable for the following conditions: short-term (4 h), long-term (2 weeks), freeze/thaw (three cycles). This qualified method was successfully applied to intravenous (IV) pharmacokinetic (PK) studies of Daporinad in mice at doses of 5, 10 and 30 mg/kg. As a result, it showed a linear PK tendency in the dose range from 5 to 10 mg/kg, but a non-linear PK tendency in the dose of 30 mg/kg. In addition, in vitro and in vivo metabolite identification (Met ID) studies were conducted to understand the PK properties of Daporinad and the results showed that a total of 25 metabolites were identified as ten different types of metabolism in our experimental conditions. In conclusion, the LC-qTOF-MS assay was successfully developed for the quantification of Daporinad in mouse plasma as well as for its in vitro and in vivo metabolite identification.
Journal Article