32 research outputs found

    Robust Co-catalytic Performance of Nanodiamonds Loaded on WO3 for the Decomposition of Volatile Organic Compounds under Visible Light

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    Proper co-catalysts (usually noble metals), combined with semiconductor materials, are commonly needed to maximize the efficiency of photocatalysis. Search for cost-effective and practical alternatives for noble-metal co-catalysts is under intense investigation. In this work, nanodiamond (ND), which is a carbon nanomaterial with a unique sp(3)(core)/sp(2)(shell) structure, was combined with WO3 (as an alternative co-catalyst for Pt) and applied for the degradation of volatile organic compounds under visible light. NDs-loaded WO3 showed a highly enhanced photocatalytic activity for the degradation of acetaldehyde (similar to 17 times higher than bare WO3), which is more efficient than other well-known co-catalysts (Ag, Pd, Au, and CuO) loaded onto WO3 and comparable to Pt-loaded WO3. Various surface modifications of ND and photoelectochemical measurements revealed that the graphitic carbon shell (sp(2)) on the diamond core (spa) plays a crucial role in charge separation and the subsequent interfacial charge transfer. As a result, ND/WO3 showed much higher production of OH radicals than bare WO3 under visible light. Since ND has a highly transparent characteristic, the light shielding that is often problematic with other carbon-based co-catalysts was considerably lower with NDs-loaded WO3. As a result, the photocatalytic activity of NDs/WO3 was higher than that of WO3 loaded with other carbon-based co-catalysts (graphene oxide or reduced graphene oxide). A range of spectroscopic and photo(electro)chemical techniques were systematically employed to investigate the properties of NDs-loaded WO3. ND is proposed as a cost-effective and practical nanomaterial to replace expensive noble-metal co-catalysts.1124Ysciescopu

    Mediating effect of life satisfaction and depression on the relationship between cognition and activities of daily living in Korean male older adults

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    This study investigated the mediating effects of life satisfaction and depression on the relationship between cognition and activities of daily living (ADL) among male older adults. A secondary analysis was conducted utilizing data from the 2020 Elderly Survey. The participant pool consisted of 4035 Korean male older adults aged 65 years and above, selected from the total survey population of 10,097. The study focused on four variables: cognition, Korean Activities of Daily Living (K-ADL), life satisfaction and depression. The main analysis employed Hayes’s PROCESS Macro for SPSS v.4.0, and Model 6 was applied to determine the mediating effect of life satisfaction and depression on the relationship between cognition and ADL. The analysis revealed a negative correlation between ADL and cognition scores. ADL scores exhibited positive correlations with both life satisfaction and depression scores. A positive correlation emerged between life satisfaction and depression scores. The examination unveiled an indirect mediating effect between life satisfaction and depression scores. It is necessary to establish an intervention strategy that considers life satisfaction and the degree of depression when establishing a strategy to predict and prevent the decline in daily living ability in older adults with cognitive decline

    Requirement for Pak3 in Rac1-induced organization of actin and myosin during Drosophila larval wound healing

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    AbstractRho-family small GTPases regulate epithelial cell sheet migration by organizing actin and myosin during wound healing. Here, we report that Pak3, but not Pak1, is a downstream target protein for Rac1 in wound closure of the Drosophila larval epidermis. Pak3-deficient larvae failed to close a wound hole and this defect was not rescued by Pak1 expression, indicating differential functions of the two proteins. Pak3 localized to the wound margin, which selectively required Rac1. Pak3-deficient larvae showed severe defects in actin-myosin organization at the wound margin and in submarginal cells, which was reminiscent of the phenotypes of Rac1-deficient larvae. These results suggest that Pak3 specifically mediates Rac1 signaling in organizing actin and myosin during Drosophila epidermal wound healing

    Diode Laser—Can It Replace the Electrical Current Used in Endoscopic Submucosal Dissection?

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    Background/Aims A new medical fiber-guided diode laser system (FDLS) is expected to offer high-precision cutting with simultaneous hemostasis. Thus, this study aimed to evaluate the feasibility of using the 1,940-nm FDLS to perform endoscopic submucosal dissection (ESD) in the gastrointestinal tract of an animal model. Methods In this prospective animal pilot study, gastric and colorectal ESD using the FDLS was performed in ex vivo and in vivo porcine models. The completeness of en bloc resection, the procedure time, intraprocedural bleeding, histological injuries to the muscularis propria (MP) layer, and perforation were assessed. Results The en bloc resection and perforation rates in the ex vivo study were 100% (10/10) and 10% (1/10), respectively; those in the in vivo study were 100% (4/4) and 0% for gastric ESD and 100% (4/4) and 25% (1/4) for rectal ESD, respectively. Deep MP layer injuries tended to occur more frequently in the rectal than in the gastric ESD cases, and no intraprocedural bleeding occurred in either group. Conclusions The 1,940-nm FDLS was capable of yielding high en bloc resection rates without intraprocedural bleeding during gastric and colorectal ESD in animal models

    Compound K, a Metabolite of Ginseng Saponin, Induces Mitochondria-Dependent and Caspase-Dependent Apoptosis via the Generation of Reactive Oxygen Species in Human Colon Cancer Cells

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    The objective of this study was to elucidate the cytotoxic mechanism of Compound K, with respect to the involvement of reactive oxygen species (ROS) and the mitochondrial involved apoptosis, in HT-29 human colon cancer cells. Compound K exhibited a concentration of 50% growth inhibition (IC50) at 20 μg/mL and cytotoxicity in a time dependent manner. Compound K produced intracellular ROS in a time dependent fashion; however, N-acetylcysteine (NAC) pretreatment resulted in the inhibition of this effect and the recovery of cell viability. Compound K induced a mitochondria-dependent apoptotic pathway via the modulation of Bax and Bcl-2 expressions, resulting in the disruption of the mitochondrial membrane potential (Δψm). Loss of the Δψm was followed by cytochrome c release from the mitochondria, resulting in the activation of caspase-9, -3, and concomitant poly ADP-ribosyl polymerase (PARP) cleavage, which are the indicators of caspase-dependent apoptosis. The apoptotic effect of Compound K, exerted via the activation of c-Jun NH2-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK), was abrogated by specific MAPK inhibitors. This study demonstrated that Compound K-mediated generation of ROS led to apoptosis through the modulation of a mitochondria-dependent apoptotic pathway and MAPK pathway

    Population Structure and Transmission Dynamics of Plasmodium vivax in the Republic of Korea Based on Microsatellite DNA Analysis

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    Vivax malaria is widely prevalent, mainly in Asia and South America with 390 million reported cases in 2009. Worldwide, in the same year, 2.85 billion people were at risk. Plasmodium vivax is prevalent not only in tropical and subtropical areas but also in temperate areas where there are no mosquitoes in cold seasons. While most malaria researchers are focusing their studies on the parasite in tropical areas, we examined the characteristics of P. vivax in South Korea (temperate area) temporally, using 10 highly polymorphic microsatellite DNA (a short tandem repeat DNA sequence) in the parasite genome, and highlighted the differences between the tropical and temperate populations. We found that the South Korean P. vivax population had low genetic diversity and low recombination rates in comparison to tropical P. vivax populations that had been reported. We also found that some of the parasite clones in the population were changing from 1994 to 2008, evidence suggesting the continual introduction of the parasite from other populations, probably from North Korea. Polymorphic DNA markers of the P. vivax parasite are useful tools for estimating the situation of its transmission in endemic areas

    Examining the health-related quality of life of middle-aged men with metabolic syndrome based on their stress level

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    Background: This study was conducted to identify the factors that affect the health-related quality of life (HRQoL) of middle-aged men with metabolic syndrome (MetS) based on their stress level using data from the Korea National Health and Nutrition Examination Survey (KNHANES). Methods: The participants of this study were men aged between 40–64 with MetS who were included in the KNHANES. The main variables of this study were HRQoL, which was measured using the EuroQol-5 Dimension (EQ-5D); general characteristics, health-related characteristics, and dietary behaviors. Results: The subjective health of the group with less stress was significantly better. Compared to the unhealthy group, the groups perceived as healthy and normal had a higher HRQoL. The economic level, suicidal ideation, and dinner arrangement (presence of family) of the stressed group were significantly associated with their HRQoL. Compared to a low economic level, the high and middle economic levels were more associated with the subjects’ HRQoL. Compared to the group without suicidal ideation, the group that experienced suicidal association had a lower HRQoL. Compared to the group that did not dine with their family, the group that dined with family had a higher HRQoL. Conclusions: The results of this study expand the scientific understanding of HRQoL based on stress among middle-aged men with metabolic syndrome. Since differences in the influence of the factors that affect HRQoL were identified based on the level of stress experienced, the stress level of middle-aged men should be considered when devising an intervention strategy to improve their HRQoL
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