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"Yoon, Jin Young"
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Conformational control of two-dimensional gold nanoparticle arrays in a confined geometry within a vesicular wall
2022
The two-dimensional (2D) assembly of gold nanoparticles (AuNPs) in a confined geometry is a rare phenomenon that has not been experimentally verified for complex systems. In this study, this process was investigated in detail using two types of block copolymers with hydrophobic and hydrophilic blocks and a series of AuNPs of three different sizes protected by hydrophobic ligands. In aqueous solutions, the selected block copolymers self-assembled into vesicular nanostructures with a hydrophobic domain in the wall, which functions as a confined geometrical space for hydrophobic AuNPs (i.e., it exerts a confinement effect and restricts the movement of AuNPs). Small-angle X-ray scattering studies revealed that AuNPs of different sizes assembled differently in the same confined geometry of the vesicular wall. In addition, optimal conditions for the formation of a regular NP array in the hydrophobic domain were determined. The AuNPs successfully self-assembled into a regular 2D lattice structure, forming a shell around the vesicle, when their size matched the thickness of the hydrophobic domain of the vesicular nanostructure. This study provides guidelines for the fabrication of nanoparticle arrays with controlled structures, which could enhance the functionality of materials and their physical properties.
Journal Article
Comparison of therapeutic effects between topical 8-oxo-2′-deoxyguanosine and corticosteroid in ocular alkali burn model
by
Im, Sang-Taek
,
Kim, Mee Kum
,
Chung, Myung-Hee
in
692/308/2778
,
692/699/3161
,
8-Hydroxy-2'-Deoxyguanosine - therapeutic use
2021
We compared the therapeutic effects of topical 8-oxo-2′-deoxyguanosine (8-oxo-dG) and corticosteroid in a murine ocular alkali burn model. (n = 128) The corneal alkali burn model was established by applying 0.1 N sodium hydroxide (NaOH), followed by treatment with 8-oxo-dG, 0.1% fluorometholone (FML), 1% prednisolone acetate (PDE), or phosphate-buffered saline (PBS) twice daily. One week later, the clinical and histological status of the cornea were assessed. Transcript levels of inflammatory cytokines and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase as well as the levels of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in the cornea, were assayed. The 8-oxo-dG and PDE groups showed marked improvements in corneal integrity and clarity when compared with the PBS group (each
p
< 0.01). The numbers of cells stained for neutrophil elastase and F4/80-positive inflammatory cells were significantly decreased, with levels of interleukin(IL)-1β, IL-6, tumor necrosis factor(TNF)-α, and total ROS/RNS amounts markedly reduced in the 8-oxo-dG, FML, and PDE groups (each
p
< 0.05). Levels of NADPH oxidase type 2 and 4 were substantially more repressed in the 8-oxo-dG-treated group than in the PDE-treated group (each
p
< 0.05). Topical 8-oxo-dG showed excellent therapeutic effects that were comparable with those treated with topical PDE in a murine ocular alkali burn model.
Journal Article
Self‐Assembly of Hydration‐Dependent Quasi‐Spherical Mixed Micelles into Selective Mesoscale Complex Crystalline Structures
2025
Over the past three decades, a variety of complex structures mimicking intermetallic compounds have been discovered in soft matter systems. However, a complete understanding of the mechanisms that govern the self‐assembly of these complex structures in aqueous solution is still lacking. Herein, we investigate the formation of mesoscale complex crystal structures with micelle packing of nonionic amphiphilic molecules in aqueous solutions using small‐angle X‐ray scattering (SAXS). The SAXS measurements revealed both unary‐micelle and binary‐micelles liquid crystalline phases, including face‐centered cubic (FCC), body‐centered cubic (BCC), Frank‐Kasper (FK) σ, and FK A15 and NaZn13, FK C14, and FK C15 phases, respectively, which arise from the interplay of composition, temperature, and time. Quantitative SAXS analyses with Le Bail refinements and electron density reconstruction indicated that EO hydration, the interfacial curvature of micelles, and micellar packing play important roles in the formation of mesoscale complex crystalline structures during the self‐assembly process of the nonionic ternary system. This study is the first demonstration of binary mesoscale complex crystalline structures with quasispherical close packing in nonionic amphiphilic aqueous solution, offering broader insights for the self‐assembly mechanism of the complex crystalline structures on soft materials. Complex mesoscale liquid crystals were selectively developed in response to external stimulus from nonionic amphiphiles (C16EO20 and EO5PO49EO5) in aqueous solution. Comprehensive X‐ray scattering analysis provides decisive results on the principles of self‐assembly of hydration‐dependent quasispherical micelles in soft matter.
Journal Article
The Relationship of Fish Functional Traits, Physicochemical Characteristics and Exotic Fish (Micropterus salmoides and Lepomis macrochirus)
by
Kim, Mooseong
,
Jang, Min-Ho
,
Bold, Misheel
in
Animal introduction
,
Aquatic ecosystems
,
Biodiversity
2024
An invasive species is defined as a biological species introduced, most often through human action, that causes direct harm, such as reducing or driving native species to extinction. This introduction can result in long-term changes to ecosystem structures and ultimately contribute to a decline in biodiversity within areas where it was not previously present. Thus, continuous monitoring and management are essential. This study examined the impact of two exotic species, largemouth bass (Micropterus salmoides) and bluegill (Lepomis macrochirus), on fish diversity in rivers across South Korea. Data from the “Stream Ecosystem Survey and Health Assessment” project, which was conducted along five major river basins between 2013 and 2021, were analyzed. The data were divided into three periods: 2013–2015, 2016–2018, and 2019–2021, covering a total of 960 sites. The results revealed that largemouth bass and bluegill were present at 360 sites (37.5%) from 2013 to 2015, 325 sites (33.9%) from 2016 to 2018, and 356 sites (37.1%) from 2019 to 2021. Additionally, when comparing sites where exotic fish were present with those where they were absent, the average number of native species was slightly higher in areas where these invasive species were present, yet the average Fish Assessment Index (FAI) value was lower. Statistically significant differences were observed in fish diversity, especially in trophic and tolerance traits. This study provides valuable insight into the impact of invasive species on South Korean river ecosystems and offers important information for developing future conservation and management strategies for biological resources.
Journal Article
Metabolic rescue ameliorates mitochondrial encephalo‐cardiomyopathy in murine and human iPSC models of Leigh syndrome
2022
Background Mice with deletion of complex I subunit Ndufs4 develop mitochondrial encephalomyopathy resembling Leigh syndrome (LS). The metabolic derangement and underlying mechanisms of cardio‐encephalomyopathy in LS remains incompletely understood. Methods We performed echocardiography, electrophysiology, confocal microscopy, metabolic and molecular/morphometric analysis of the mice lacking Ndufs4. HEK293 cells, human iPS cells‐derived cardiomyocytes and neurons were used to determine the mechanistic role of mitochondrial complex I deficiency. Results LS mice develop severe cardiac bradyarrhythmia and diastolic dysfunction. Human‐induced pluripotent stem cell‐derived cardiomyocytes (iPS‐CMs) with Ndufs4 deletion recapitulate LS cardiomyopathy. Mechanistically, we demonstrate a direct link between complex I deficiency, decreased intracellular (nicotinamide adenine dinucleotide) NAD+/NADH and bradyarrhythmia, mediated by hyperacetylation of the cardiac sodium channel NaV1.5, particularly at K1479 site. Neuronal apoptosis in the cerebellar and midbrain regions in LS mice was associated with hyperacetylation of p53 and activation of microglia. Targeted metabolomics revealed increases in several amino acids and citric acid cycle intermediates, likely due to impairment of NAD+‐dependent dehydrogenases, and a substantial decrease in reduced Glutathione (GSH). Metabolic rescue by nicotinamide riboside (NR) supplementation increased intracellular NAD+/ NADH, restored metabolic derangement, reversed protein hyperacetylation through NAD+‐dependent Sirtuin deacetylase, and ameliorated cardiomyopathic phenotypes, concomitant with improvement of NaV1.5 current and SERCA2a function measured by Ca2+‐transients. NR also attenuated neuronal apoptosis and microglial activation in the LS brain and human iPS‐derived neurons with Ndufs4 deletion. Conclusions Our study reveals direct mechanistic explanations of the observed cardiac bradyarrhythmia, diastolic dysfunction and neuronal apoptosis in mouse and human induced pluripotent stem cells (iPSC) models of LS. Leigh syndrome (LS) is a severe mitochondrial encephalomyopathy that may involve heart. Its metabolic derangement is characterized by NAD+ deficiency and impairment of several NAD+‐dependent metabolic enzymes and Sirtuins. Nicotinamide Riboside restores Sirt1 function, reverses hyperacetylation of several crucial proteins, including Nav1.5 and SERCA2 in cardiomyocytes, and p53 in the brain, leading to amelioration of bradycardia, neuronal loss and encephalopathy.
Journal Article
The microRNA‐204‐5p inhibits APJ signalling and confers resistance to cardiac hypertrophy and dysfunction
by
London, Barry
,
Gaddam, Ravinder Reddy
,
Li, Qiuxia
in
Animals
,
Apelin Receptors - antagonists & inhibitors
,
Apelin Receptors - metabolism
2022
Background MicroRNAs regulate cardiac hypertrophy development, which precedes and predicts the risk of heart failure. microRNA‐204‐5p (miR‐204) is well expressed in cardiomyocytes, but its role in developing cardiac hypertrophy and cardiac dysfunction (CH/CD) remains poorly understood. Methods: We performed RNA‐sequencing, echocardiographic, and molecular/morphometric analysis of the heart of mice lacking or overexpressing miR‐204 five weeks after trans‐aortic constriction (TAC). The neonatal rat cardiomyocytes, H9C2, and HEK293 cells were used to determine the mechanistic role of miR‐204. Results The stretch induces miR‐204 expression, and miR‐204 inhibits the stretch‐induced hypertrophic response of H9C2 cells. The mice lacking miR‐204 displayed a higher susceptibility to CH/CD during pressure overload, which was reversed by the adeno‐associated virus serotype‐9‐mediated cardioselective miR‐204 overexpression. Bioinformatic analysis of the cardiac transcriptomics of miR‐204 knockout mice following pressure overload suggested deregulation of apelin‐receptor (APJ) signalling. We found that the stretch‐induced extracellular signal‐regulated kinase 1/2 (ERK1/2) activation and hypertrophy‐related genes expression depend on the APJ, and both of these effects are subject to miR‐204 levels. The dynamin inhibitor dynasore inhibited both stretch‐induced APJ endocytosis and ERK1/2 activation. In contrast, the miR‐204‐induced APJ endocytosis was neither inhibited by dynamin inhibitors (dynasore and dyngo) nor associated with ERK1/2 activation. We find that the miR‐204 increases the expression of ras‐associated binding proteins (e.g., Rab5a, Rab7) that regulate cellular endocytosis. Conclusions Our results show that miR‐204 regulates trafficking of APJ and confers resistance to pressure overload‐induced CH/CD, and boosting miR‐204 can inhibit the development of CH/CD. miR‐204 regulates trafficking of APJ and confers resistance to pressure overload‐induced cardiac hypertrophy and cardiac dysfunction.
Journal Article
Spatial-Arrangement-Assisted Emission Energy Fine Tuning of CdSe Quantum Dots (QDs) in QD–Block Copolymer Complexes
by
Jang, Jong Dae
,
Yoon, Young-Jin
,
Han, Young Soo
in
Absorption
,
Aqueous solutions
,
Block copolymers
2024
Quantum dots (QDs) exhibit size-dependent optical properties, where both the absorption and fluorescence energy levels vary with QD size. However, this dependence results in a discontinuity of intrinsically accessible energy levels for the bandgap, posing challenges in achieving precise energy tuning within a specific range. Herein, we demonstrate emission energy control of QDs with identical absorption energy levels by manipulating the spatial arrangement of QDs within QD–polymer complexes through hydrophobic interactions. The phase behavior of the QD–polymer complexes was modulated by adjusting the mass fraction of hydrophilic and hydrophobic blocks in the block copolymer, utilizing two types of amphiphilic block copolymers and varying temperatures. The QDs were spontaneously trapped within the hydrophobic region of the polymer template in water, resulting in spherical, cylindrical, and vesicle structures of QD–polymer complexes, corresponding to spherical, cylindrical, and layered assemblies of QDs, respectively. Depending on the QDs’ location within the QD–polymer complex, the surface area in contact with water varied, leading to different degrees of oxidation and, consequently, a change in the fluorescence energy level of QDs. This study introduces a novel method to fine tune the emission energy (<15 eV) of QDs by adjusting the polymer form factor without complicated procedures.
Journal Article
Clinical and pathological characteristics of early-onset colorectal cancer in South Korea
2023
Abstract
Background:
Early-onset colorectal cancer (EOCRC) may differ by race and ethnicity, and recently South Korea has witnessed a surge in cases. We aimed to evaluate the clinical and pathological features of patients with EOCRC, and to determine the predictors of overall survival.
Methods:
In this retrospective study, EOCRC was defined as CRC diagnosed in patients aged < 50 years, and late-onset CRC was defined as CRC diagnosed in those over 75 years of age. The clinical and pathological characteristics of patients with EOCRC were compared with late-onset CRC. We also used multivariable Cox proportional hazard models to find predictors of overall survival in patients with EOCRC.
Results:
The proportion of early-onset CRC was 9.1% of 518 patients with CRC, and the clinical and pathological characteristics were similar between early-onset (n = 47) and late-onset CRC (n = 134). However, EOCRC had a preponderance for distal tumor location (70.2% vs. 50.7%, P = 0.02) and T1-2 stage disease (23.4% vs. 11.2%, P = 0.04), compared with those of late-onset CRC. Using multivariable Cox proportional hazard models, only vascular invasion (hazard ratio = 8.75, 95% confidence interval 1.139‒67.197) was found to be a risk factor for overall survival (P = 0.04) for patients with CRC.
Conclusion:
EOCRC had preponderance for distal tumor location and early T-stage disease, compared with late-onset CRC. Considering the increasing incidence of EOCRC, more studies on clinical and pathological characteristics of EOCRC may be warranted.
Journal Article
Use of raw-state bottom ash for aggregates in construction materials
2019
The recycling of raw-state bottom ash as it is holds an advantage from an economic and environmental standpoint in that it omits pre-processes such as milling and wetting. Its physical and chemical properties are first characterized for the purpose, and then the use of raw-state bottom ash for aggregates in construction materials is proposed. Preplaced aggregate concrete or dry-mixing concrete scheme can be selectively applied according to the particle size requirement of bottom ash aggregate. Preplaced bottom ash aggregate concrete is produced by placing the bottom ash aggregate in formwork and injecting grout to fill the voids. To ensure the injectability of the grout, relatively large-sized particles, greater than 5 mm, are recommended to be used. In the case of dry-mixing concrete, this is originally designed for manufacturing concrete masonry units and concrete blocks with a low water-to-cement ratio and consolidated zero-slump concrete using a mechanized vibrating mold. The experimental results show that bottom ash aggregate concrete has moderate compressive strength with a low density.
Journal Article
Herbal Medicine for Postpartum Pain: A Systematic Review of Puerperal Wind Syndrome (Sanhupung)
by
Lee, Hee-Yoon
,
Yoon, Young-Jin
,
Cho, Su-Jin
in
Acupuncture
,
Breastfeeding & lactation
,
Care and treatment
2023
Mothers in the postpartum period often experience musculoskeletal disorders and pain, impacting their ability to care for themselves and their infants. Conventional treatments have limitations, prompting interest in alternative options like herbal medicine. This systematic review aimed to confirm the effectiveness and safety of herbal medicine treatment to improve maternal health in patients with postpartum pain (puerperal wind syndrome). We searched eight electronic databases for randomized controlled trials (RCTs) to evaluate the effects of herbal medicines on puerperal wind syndrome. Nine RCTs, including 652 patients, were selected. Following a meta-analysis of RCTs, both herbal medicine and combination treatments improved the visual analog scale scores, total effective rate, scores of Traditional Chinese Medicine syndromes, Oswestry Disability Index, and quality of life in patients with role-emotional puerperal wind syndrome. All adverse events were minor, and the incidence rate was not high compared with that of the control group. In conclusion, herbal medicine supports the improvement in pain, other systemic symptoms, and the quality of life of patients with puerperal wind syndrome. Moreover, no serious side effects were observed; therefore, herbal medicines appear to be safe. It can be the preferred treatment option for puerperal wind syndrome, which is currently managed symptomatically.
Journal Article