• The Korean Journal of Physiology and Pharmacology
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• v.15 no.3
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• pp.179-187
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• 2011

Regulation of B cell receptor (BCR)-induced $Ca^{2+}$ signaling by CD40 co-stimulation was compared in long-term BCR-stimulated immature (WEHI-231) and mature (Bal-17) B cells. In response to long-term pre-stimulation of immature WEHI-231 cells to ${\alpha}$-IgM antibody (0.5~48 hr), the initial transient decrease in BCR-induced $[Ca^{2+}]_i$ was followed by spontaneous recovery to control level within 24 hr. The recovery of $Ca^{2+}$ signaling in WEHI-231 cells was not due to restoration of internalized receptor but instead to an increase in the levels of $PLC{\gamma}2$ and $IP_3R-3$. CD40 co-stimulation of WEHI-231 cells prevented BCR-induced cell cycle arrest and apoptosis, and it strongly inhibited the recovery of BCR-induced $Ca^{2+}$ signaling. CD40 co-stimulation also enhanced BCR internalization and reduced expression of $PLC{\gamma}2$ and $IP_3R-3$. Pre-treatment of WEHI-231 cells with the antioxidant N-acetyl-L-cysteine (NAC) strongly inhibited CD40-mediated prevention of the recovery of $Ca^{2+}$ signaling. In contrast to immature WEHI-231 cells, identical long-term ${\alpha}$-IgM pre-stimulation of mature Bal-17 cells abolished the increase in BCR-induced $[Ca^{2+}]_i$, regardless of CD40 co-stimulation. These results suggest that CD40-mediated signaling prevents antigen-induced cell cycle arrest and apoptosis of immature B cells through inhibition of sustained BCR-induced $Ca^{2+}$ signaling.

• Bulletin of the Korean Chemical Society
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• v.35 no.4
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• pp.1182-1190
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• 2014

$Cd_{1-x}Zn_xS$-sensitized $K_4Nb_6O_{17}$ composite photocatalysts (designated $Cd_{1-x}Zn_xS/K_4Nb_6O_{17}$) were prepared via a simple deposition-precipitation method. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectrometry (EDS), $N_2$ sorption, ultraviolet-visible light diffuse reflectance spectroscopy (UV-Vis DRS), photoluminescence measurements (PL), and X-ray photoelectron spectroscopy (XPS). The $Cd_{0.8}Zn_{0.2}S$ particles were scattered on the surface of $K_4Nb_6O_{17}$, and had a relatively uniform size distribution around 50 nm. The absorption edge of $K_4Nb_6O_{17}$ was shifted to the visible light region and the recombination of photo-generated electrons and holes suppressed after $Cd_{0.8}Zn_{0.2}S$ loading. The $Cd_{0.8}Zn_{0.2}S$(25 wt %)/$K_4Nb_6O_{17}$ composite possessed the highest photocatalytic activity for hydrogen production under visible light irradiation, evolving 8.278 mmol/g in 3 h. Recyclability tests were performed, and the composite photocatalysts were found to be fairly stable. The mechanism of charge separation between the photogenerated electrons and holes at the $Cd_{0.8}Zn_{0.2}S/K_4Nb_6O_{17}$ composite was discussed.

• Korean Journal of Crystallography
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• v.9 no.1
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• pp.53-63
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• 1998

The Cd1-xZnxS thin films were grown on the Si(100) wafers by a hot wall epitaxy method (HWE). the source and substrate temperature are 600℃ and 440℃, respectively. The crystalline structure of epilayers was investigated by double crystal X-ray diffraction (DCXD). Hall effect on the sample was measured by the van der Pauw method and the carrier density and mobility dependence of Hall characteristics on temperature was also studied. In order to explore the applicability as a photoconductive cell, we measured the sensitivity (γ), the ratio of photocurrent to darkcurrent (pc/dc), maximum allowable power dissipation (MAPD), spectral response and response time. The results indicated that the best photoconductive characteristic were observed in the Cd0.53Zn0.47S samples annealed in Cu vapor comparing with in Cd, Se, air and vacuum vapour. Then we obtained the sensitivity of 0.99, the value of pc/dc of 1.65 × 107, the MAPD of 338mW, and the rise and decay time of 9.7 ms and 9.3 ms, respectively.

• Journal of Ginseng Research
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• v.44 no.1
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• pp.161-167
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• 2020

Background: The ascomycete fungi Cylindrocarpon destructans (Cd) and Fusarium solani (Fs) cause ginseng root rot and significantly reduce the quality and yield of ginseng. Cd produces the secondary metabolite radicicol, which targets the molecular chaperone Hsp90. Fs is resistant to radicicol, whereas other fungal genera associated with ginseng disease are sensitive to it. Radicicol resistance mechanisms have not yet been elucidated. Methods: Transcriptome analyses of Fs and Cd mycelia treated with or without radicicol were conducted using RNA-seq. All of the differentially expressed genes (DEGs) were functionally annotated using the Fusarium graminearum transcript database. In addition, deletions of two transporter genes identified by RNA-seq were created to confirm their contributions to radicicol resistance. Results: Treatment with radicicol resulted in upregulation of chitin synthase and cell wall integrity genes in Fs and upregulation of nicotinamide adenine dinucleotide dehydrogenase and sugar transporter genes in Cd. Genes encoding an ATP-binding cassette transporter, an aflatoxin efflux pump, ammonium permease 1 (mep1), and nitrilase were differentially expressed in both Fs and Cd. Among these four genes, only the ABC transporter was upregulated in both Fs and Cd. The aflatoxin efflux pump and mep1 were upregulated in Cd, but downregulated in Fs, whereas nitrilase was downregulated in both Fs and Cd. Conclusion: The transcriptome analyses suggested radicicol resistance pathways, and deletions of the transporter genes indicated that they contribute to radicicol resistance.

• Journal of the Korean GEO-environmental Society
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• v.19 no.11
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• pp.15-22
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• 2018

The main objective of this study was to analyse heavy metals in sediments obtained from Gwangan bridge and to evaluate pollution intensity of the sites. To evaluate pollution intensity of the sites, we used enrichment factor (EF), geoaccumulation index, potential ecological risk factor (PERF), and mean PEL quotient. Pollution intensities of these sites were evaluated by above methods, and we found most dangerous heavy metal and polluted sites. All sites showed non polluted or low risk for the heavy metals such as Cr, Cu, Ni, Pb, and Zn, but all sites were categorized as minor enrichment for Cd. G4 was evaluated as moderately polluted by Cd ($I_{geo}$) but other sites were unpolluted by heavy metals. In summary, Cd was found to be higher concentrations for all sites. For G4 and G5 sites, Pb and Zn in addition to Cd were higher than other sites.

• YAKHAK HOEJI
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• v.57 no.1
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• pp.37-42
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• 2013

In this present study, we determined the immunoregulatory activity of ginsenoside Rd extract from Panax ginseng. To determine the activity, we tested Rd against $CD4^+$ Th cells in a murine model of type 1 diabetes, which involves Th1-dominant immunity. The type 1 diabetes was caused by streptozotocin (STZ) and the severity of the diabetes was evaluated by measuring the degree of hyperglycemia, a major symptom of diabetes. The data resulting from experiments showed that ginsenoside Rd induced a greater level of Th1 type cytokines [IFN-${\gamma}$ & IL-2] than Th2 type [IL-4 & IL-10] (P<0.05), which was determined by cytokine profile analysis. In the animal model of diabetes, the depletion of $CD4^+$ Th cells by a treatment of anti-CD4 mAb resulted in considerably lower values of blood-glucose levels than those of the mAb-untreated mice, which indicates that the Th1 immune response from $CD4^+$ Th cells are responsible for diabetes. Based on these observations, the effect of Rd on diabetes was examined in the same animal model. Results showed that Rd-treated mice groups had increased levels of blood glucose compared to Rd-untreated mice groups that were used as a negative control (P<0.05). In other words, Rd aggravated the diabetes via the Th1 immune response. In conclusion, ginsenoside Rd had an immunoregulatory activity of Th1-dominant immunity.

• Clinical and Experimental Pediatrics
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• v.64 no.6
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• pp.301-309
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• 2021

Background: Celiac disease (CD) is a chronic autoimmune enteropathy. It results from genetic predisposition and exposure to gluten-containing food. The prevalence and presentation of CD vary among populations. Purpose: This study aimed to describe the prevalence and clinical characteristics of CD in children in Bahrain. Methods: We retrospectively reviewed the medical records of children diagnosed with CD in the pediatric department, Salmaniya Medical Complex, Bahrain, in 1988-2018. Their clinical, biochemical, serological, and histopathological findings were documented. Adherence to the recommended gluten-free diet (GFD) was assessed. Results: Of 86 patients with CD, 67 were included. The CD prevalence was 0.02%. A significant increase in prevalence in the last decade was observed (P<0.0001). Thirty-eight patients (56.7%) were males. The median (interquartile range) age at presentation was 4.45 (1.5-7.3) years. A family history of CD was positive in 13 out of 43 patients (30.2%). Pallor and failure to thrive were the most common presentations. The most frequent associated disease was iron-deficiency anemia in 23 patients (69.7%). Positive serology was found in 32 of 45 patients (71.1%). Marsh-Oberhuber type III was found in 16 of 35 patients (45.7%). Seropositive patients were significantly older (P=0.025) and had more severe duodenal histology (P=0.002). Adherence to GFD was poor in 27 patients (64.3%). Conclusion: This study revealed a significant increase in CD prevalence over the last decade. Atypical presentations were frequent. Most patients had poor adherence to GFD.

• Resources Recycling
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• v.28 no.1
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• pp.23-31
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• 2019

Cementation is one of economical and efficient recycling method precipitating the metal ion in solution by adding another active metal. In this study for optimizing cadmium recovery efficiency, it was performed as a function of the effect of pH, temperature, particle size, and input amount of zinc in 0.1 M $CdSO_4$ solution and Ni-Cd battery leaching solutions, respectively. The particle size of zinc and temperature were key factors for Cd cementation and it was confirmed that the input amount of 2.6 of Zn/Cd ratio using granular-type zinc was optimal condition for selective Cd recovery efficiency at $25^{\circ}C$.

• Korean Chemical Engineering Research
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• v.59 no.3
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• pp.450-454
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• 2021

Currently, gamma nuclide analysis is mainly used using inorganic scintillators or semiconductor detectors. These detectors have high resolution but there are less economical, limited in size, and low process ability than plastic scintillators. Therefore, quantum dot-based plastic scintillator was developed using the advantages of the quantum dot nanomaterial and the conventional plastic scintillator. In this study, efficient plastic scintillator was fabricated by adding CdS/ZnS based on the most widely used Cd-based nanomaterial in a polystyrene matrix. In addition, the performance of the commercial plastic scintillator was compared and it was analyzed through radiological measurement experiments. The detection efficiency of fabricated plastic scintillator was higher than commercial plastic scintillator, EJ-200. It is believed that this fabricated plastic scintillator can be used as a radioactivity analyzer in the medical and nuclear facility fields.

• BMB Reports
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• v.53 no.12
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• pp.622-627
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• 2020

Cancer stem cells (CSCs) or tumor-initiating cells are thought to play critical roles in tumorigenesis, metastasis, drug resistance, and tumor recurrence. For the diagnosis and targeted therapy of CSCs, the molecular identity of biomarkers or therapeutic targets for CSCs needs to be clarified. In this study, we identified CD166 as a novel marker expressed in the sphere-forming CSC population of A2780 epithelial ovarian cancer cells and primary ovarian cancer cells. The CD166+ cells isolated from A2780 cells and primary ovarian cancer cells highly expressed CSC markers, including ALDH1a1, OCT4, and SOX2, and ABC transporters, which are implicated in the drug resistance of CSCs. The CD166+ cells exhibited enhanced CSC-like properties, such as increased sphere-forming ability, cell migration and adhesion abilities, resistance to conventional anticancer drugs, and high tumorigenic potential in a xenograft mouse model. Knockdown of CD166 expression in the sphere-forming ovarian CSCs abrogated their CSC-like properties. Moreover, silencing of CD166 expression in the sphere-forming CSCs suppressed the phosphorylation of focal adhesion kinase, paxillin, and SRC. These results suggest that CD166 plays a key role in the regulation of CSC-like properties and focal adhesion kinase signaling in ovarian cancer.