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        검색결과 7,942

        721.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Crowded pet shops can become infected with various pathogens. Although dog carriers of Clostridioides difficile tend to be asymptomatic, the toxigenic strains sometimes cause gastrointestinal symptoms in humans. The present study was conducted to determine the infection rate of C. difficile in pet shops. The feces of 137 dogs younger than one year of age, collected from four pet shops, were assessed by culture and PCR. Carriage rates of C. difficile in dogs aged ≤90, 91-180, and ≥181 day-old were 12.2% (10/82, 95% confidence interval: 6.0-21.3%), 0.0% (0/42, 95% confidence interval: 0.0-8.4%), and 7.7% (1/13, 95% confidence interval: 0.2-36.0%), respectively. Five C. difficile isolates carried genes encoding toxins A and B, while the remaining isolates contained only toxin B. However, none of the C. difficile carriers had diarrhea. These results highlight the necessity of promoting adequate hygiene precautions in pet shops to prevent infection by C. difficile.
        4,000원
        722.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Germ cells undergo towards male or female pathways to produce spermatozoa or oocyte respectively which is essential for sexual reproduction. Mesenchymal stem cells (MSCs) have the potential of trans-differentiation to the multiple cell lineages. Methods: Herein, rat MSCs were isolated from bone marrow and characterized by their morphological features, expression of MSC surface markers, and in vitro differentiation capability. Results: Thereafter, we induced these cells only by retinoic acid supplementation in MSC medium and, could able to show that bone marrow derived MSCs are capable to trans-differentiate into male germ cell-like cells in vitro. We characterized these cells by morphological changes, the expressions of germ cell specific markers by immunophenotyping and molecular biology tools. Further, we quantified these differentiated cells. Conclusions: This study suggests that only Retinoic acid in culture medium could induce bone marrow MSCs to differentiate germ cell-like cells in vitro . This basic method of germ cell generation might be helpful in the prospective applications of this technology.
        4,000원
        723.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Toll-like receptor 4 (TLR4) is known to contribute to the modulation of insulin resistance and systemic inflammation seen in obesity and the metabolic syndrome. The present study was performed to investigate the fertility competence of TLR4 knock out male mice (TLR4 mice) on a high-fat diet (HFD), compared to a normal-chow diet (NCD). The controls included wildtype (WT) mice fed on a HFD or NCD. Six-week-old male mice were fed with either a NCD or HFD for 20 weeks. Body and organ weights, serum levels of glucose, triglycerides and hepatoxicity, sperm quality and spermatogenesis were observed after the sacrifice. Also, randomly selected male mice were mated with virgin female mice after feeding of 19 weeks. The weight of the body and organs increased in WT and TLR4 mice on a HFD compared to those of mice on a NCD. The weights of the reproductive organs did not vary among the treatment groups. The motility and concentration of the epididymal spermatozoa decreased in both WT and TLR4 mice fed a HFD. The pregnancy rate and litter size declined in the HFD-fed WT mice compared to the HFD-fed TLR4 mice. In conclusion, the HFD alters energy and steroid metabolism in mice, which may lead to male reproductive disorders. However, fertility competence was somewhat restored in HFD-fed TLR4 male mice, suggesting that the TLR4 is involved in testis dysfunction due to metabolic imbalance.
        4,300원
        724.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study assessed the utility of netted melon ‘Top Earl’s’ and cantaloupe melon ‘Alex’ as functional fruits by analysing their moisture content, vitreous sugar, folic acid, citric acid, and beta-carotene levels. High-performance liquid chromatography (HPLC) was used to analyse the free sugar, folic acid, citric acid, and beta-carotene levels. The moisture content was not significantly different between ‘Top Earl’s’ and ‘Alex.’ The glucose, sucrose, and fructose contents were three, two, and one-and-a-half fold higher in ‘Alex’ than in ‘Top Earl’s.’ Moreover, citric acid was approximately three times higher in ‘Alex’ than that in Top Earl’s.’ However, the folic acid content was higher in ‘Top ‘Earl’s’ than ‘Alex,’ and the amount was 124 μg / 100 g FW and 112 μg / 100 g FW respectively. ‘Beta-carotene was undetectable in ‘Top Earl’s,’ whereas it was 1000 μg / 100 g FW in ‘Alex.’ β-carotene, a substance that is converted in the body into vitamin A and acts as an antioxidant, is an important component in healthy food. These results suggested that the cantaloupe melon ‘Alex’ has a higher free sugar content and functional ingredients, such as antioxidants, including citric acid and beta carotene, than the netted melon ‘Top Earl’s.’
        4,000원
        731.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        애긴노린재는 긴노린재과에 속하며 한국을 포함한 동아시아 국가의 다양한 곡물 및 관상용 식물의 주요 해충으로 여겨진다. 본 연구에서는 애긴노린재의 17,367 bp 미토콘드리아 유전체에서 13개의 protein-coding genes, 22개의 transfer RNA genes, 2개의 ribosomal RNA genes 과 non-coding A+T rich region를 확인하였다. G+C content는 23%로 나타났고 다른 긴노린재과와의 염기서열 유사성이 N. cymoides (94.5%), N. fuscovittatus (91.7%)으로 높은 것을 발견하였다. 애긴노린재의 미토콘드리아 유전체 정보는 향후 긴노린재과의 진화 연구와 해충 방제를 위한 정보로 널리 사용될 수 있다.
        4,000원
        732.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        한반도 분포 여부가 불확실했던 뿌리잎벌레류 Sominella Jacobson, 1908 속이 북한산 S. macrocnemia (Fischer von Waldheim, 1824) 표 본의 발견으로 분포가 확인되었다. 이 종의 표본사진, 진단형질 및 한반도 분포지도를 제공하였다.
        3,000원
        733.
        2023.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The rapid synthesis techniques and interesting multidisciplinary applications make carbon nanodots (CNDs) stand out from semiconductor quantum dots. Moreover, CNDs derived from green precursors have gained more importance beyond chemically derived CNDs due to sustainable synthesis opportunities. However, the presence of molecular impurities or intermediates or fluorophores was neglected during the entire process. Herein, we illustrate the sustainable synthesis of CNDs from Hemigraphis alternata plant leaves with extended carbonization procedure (3 and 9 min) along with simultaneous ethylene glycol and diethyl ether solvent treatment method for the successful removal of interfering fluorophores. To unravel the distinction between purified CNDs (P-CNDs) and organic fluorescent carbon nanostructures (org-FCNs), we carried out photophysical, structural, and morphological studies. A quantum yield (QY) of 69 and 42% was observed for crude org-FCNs, and crude P-CNDs; however after purification, QY of 1% and absence of one component from the fluorescent decays curve suggest the removal of fluorophores. Further, HR-TEM and DLS studies showed the quasi-spherical amorphous particles having < 10 nm particle size for P-CNDs. Besides, in vitro biocompatibility investigation and cellular uptake assay (1–100 μg/mL) against the MDA-MB 468 cell lines proves the ≥ 95% cell viability and good internalization for both org-FCNs and P-CNDs. Hence, our study shows the presence of fluorophore impurities in plant-derived CNDs, the removal and resemblance in biocompatibility properties. Hence, this information can be considered during the synthesis and isolation of CNDs. Simple and effective removal of impurities to harvest pure carbon nanodots (CNDs) through solvent-based selective separation method, and revelation of the cocktail flourphores similar to biocompatible blue fluorescent CNDs were studied.
        4,900원
        734.
        2023.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, superior carbon nanotubes (CNT) were chemically modified with itaconic acid (IA) and a polyaniline (PANI) composite was formed and used to remove methylene blue (MB) dye from an aqueous solution. The capacity of CNTs modified with IA (IA/CNT) and composited with PANI (PANI/CNT) to remove MB dye from an aqueous solution was compared and investigated. The effects of parameters such as pH (3–10), adsorbent dose (0.8–8 g/L), initial dye concentration (10–100 mg/L), and temperature (25–55 °C) on MB adsorption were investigated. IA/CNT and PANI/CNT adsorbents were characterized by analyzes such as Fourier Transform Infrared Spectroscopy (FT-IR), Field Emission Scanning Electron Microscopy (FE-SEM), transmission electron microscope (TEM), and Brunauer, Emmett and Teller (BET). It was determined that the isotherm data fit the Langmuir isotherm model. The maximum adsorption capacity (qmax) of PANI/CNT and IA/CNT calculated according to this model (at 25 °C) was 12.78 and 32.78 mg g− 1, respectively. Thermodynamic analysis results showed that the adsorption was exothermic, feasible, and spontaneous. It can be said that the possible mechanism of MB on PANI/CNT and IA/CNT adsorbents occurs with the participation of π–π interaction, electrostatic attraction and hydrogen bonding.
        4,800원
        735.
        2023.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The rational evaluation of carbon-based conductive ink performance is critical to both industrial production and applications. Herein, a model to evaluate writing performance of conductive ink by line resistance was proposed by investigating possible relations among different parameters and establishing relevant model to estimate ink writing performance. Bulk conductive inks were prepared and characterized to provide samples for model. To improve the precision of model, the impact of external factors including writing speed and angle was studied. Nonlinear regression and back propagation artificial neural network were employed to estimate line resistance, and cross check validation was conducted to prove robustness and precision of model. Most importantly, the investigation will open up a new path for the exploration of other carbon-based handwritten electronic devices.
        4,000원
        736.
        2023.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        With a strive to develop light-weight material for automotive and aerospace applications, aluminum-based hybrid nanocomposites (AHNCs) were manufactured utilizing the compocasting approach in this study. Chopped carbon fibers (CFs) are reinforced along with different weight fractions of nanoclay (1–5%) in the matrix of AA6026 forming AHNCs. The AHNCs specimens were examined by microstructural analysis, mechanical characterization, fatigue, and corrosion strength as per ASTM guidelines. Electroless plating method is adopted for coating CFs with copper to improve the wettability with matrix. SEM pictures of manufactured composites reveal thin inter-dendritic aluminum grains with precipitate particle of eutectic at intergranular junctions, as well as nanoclay particles that have precipitated in the matrix. Tensile strength (TS) rises with inclusion of nanoclay up to a maximum of 212.46 MPa for 3% nanoclay reinforcement, after which the TS is reduced due to non-homogeneity in distribution, agglomeration and de-bonding of nanoparticles. Similarly, micro-hardness increases with addition of 3% nanoclay after which it decreases. Higher energy absorption was achieved with 3% nanoclay reinforced hybrid and a significant improvement in flexural strength was obtained. With addition of both CFs and nanoclay, the fatigue strength of the hybrid composite tends to increase due to flexible CFs and high surface area nanoclays which strengthen the grain boundaries until 3% addition. Addition of nanoclay lowers the corrosion rate with nanoclays filling the crevices and voids in the matrix.
        4,600원
        737.
        2023.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        An hydrogen adsorption study on graphene-based surfaces consisting of nitrogen-doped graphene and core–shell type catalysts of initially Pd13 , Pt13 , PdPt12 and PtPd12 core–shells, is presented in this work. Density functional theory results indicate correlation between charge transfer and structural properties, hydrogen adsorption energies, magnetic behavior and electronic properties. Reduction of hydrogen, together with higher values of charge transfer was observed for high hydrogen dissociation, compared to the case of non-hydrogen dissociation. In some cases, these values may be almost an order of magnitude larger than that of non-hydrogen dissociation. Hydrogen dissociation is also related to oxidation of the surface and correlates with a non-core shell-type structure, high adsorption energies and low magnetic moments, in general. Besides, core shell-type structure dramatically changes the magnetic and electronic properties of charge transfer. The results obtained in this work may provide important information for storing hydrogen.
        4,000원
        738.
        2023.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Biomass-derived porous carbon is an excellent scientific and technologically interesting material for supercapacitor applications. In this study, we developed biomass-derived nitrogen-doped porous carbon nanosheets (BDPCNS) from cedar cone biomass using a simple KOH activation and pyrolysis method. The BDPCNS was effectively modified at different temperatures of 600 °C, 700 °C, and 800 ℃ under similar conditions. The as-prepared BDPCNS-700 electrode exhibited a high BET surface area of 2883 m2 g− 1 and a total pore volume of 1.26 cm3 g− 1. Additionally, BDPCNS-700 had the highest electrical conductivity (11.03 cm− 1) and highest N-doped content among the different electrode materials. The BDPCNS-700 electrode attained a specific capacitance of 290 F g− 1 at a current density of 1 A g− 1 in a 3 M KOH electrolyte and an excellent longterm electrochemical cycling stability of 93.4% over 1000 cycles. Moreover, the BDPCNS-700 electrode had an excellent energy density (40.27 Wh kg− 1) vs power density (208.19 W kg− 1). These findings indicate that BDPCNS with large surface areas are promising electrode materials for supercapacitors and energy storage systems.
        4,300원
        739.
        2023.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study platform, electrocatalytic detection of the antibiotic chloramphenicol (CAP) in phosphate buffer (pH 7) was easily achieved using a carbon paste electrode modified with NiO nanoparticles (note NiO-CPE). The peak reduction potential of chloramphenicol on the modified electrode is at (− 0.60 V/NiO-CPE vs. Ag/AgCl), its electrochemical behavior is completely irreversible, and controlled by adsorption phenomena. An excellent electrocatalytic activity has been demonstrated by the modified elaborated electrode towards the NO2 attracting group on the side chain of chloramphenicol. The structure and chemical composition of the NiO-CPE sensor were analyzed by SEM, and the X-ray diffraction results indicated that nickel oxide microcrystals were formed on the carbon sheets. The electrochemical characteristics of the NiO-CPE sensor were examined by cyclic voltammetry and electrochemical impedance spectroscopy in comparison with the unmodified carbon. Since the DPV technique allows plotting the linearity curve between the electrocatalytic current intensity of the Chloramphenicol peak and their concentration, the proposed sensor showed a remarkable detection limit of 1.08 × 10– 8 mol/L M (S/N = 3) and a wide determination range from 100 to 0.1 μM for Chloramphenicol. The developed sensor was successfully applied in the detection of Chloramphenicol in real samples.
        5,500원
        740.
        2023.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Here, we report the preparation of microporous-activated carbons from a Brazilian natural lignocellulosic agricultural waste, cupuassu shell, by pyrolysis at 500 ºC and KOH activation under different experimental conditions and their subsequent application as adsorbent for CO2 capture. The effect of the KOH:precursor ratio (wt/wt%) and the activation temperature on the porous texture of activated carbons have been studied. The values of specific surface area ranged from 1132 to 2486 m2/ g, and the overall micropore volume ranged from 0.73 to 1.02 cm3/ g. Carbons activated with 2:1 ratio of KOH and activation temperature of 700 ºC presented a CO2 adsorption at 1 bar of 7.8 and 4.4 mmol/g at 0 °C and 25 ºC, respectively. The isosteric heat of adsorption, Qst , was calculated for all samples by applying the Clausius–Clapeyron approach to CO2 adsorption isotherms at both temperatures. The values of CO2 adsorption capacities are among the highest reported in the literature, especially for activated carbons produced from biomass.
        4,000원