Determination of Hg2+ Based on the Selective Enhancement of Peroxidase Mimetic Activity of Hollow Porous Gold Nanoparticles

Mingzhen Guo,Jiang He,Shuang Ma,Xiaohan Sun,Mingda Zheng 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2017 NANO Vol.12 No.4

In this paper, a novel colorimetric biosensor for Hg2+ is presented based on Hg2+ stimulated peroxidase-like activity of hollow porous gold nanoparticles (HPGNPs). Under mild conditions, HPGNPs show high catalytic activity toward the oxidation of 3, 3' , 5, 5' -tetramethylbenzidine (TMB) using H2O2 as an oxidant. The peroxidase-like activity of HPGNPs is "switched-on" selectively in the presence of Hg2+, which permitted a novel and facile colorimetric sensor for Hg2+. This method exhibits many merits like high selectivity and sensitivity. As low as 18.5 nM Hg2+ could be determined at a linear range from 0.5 x 10 -6 M to 50 x 10 -6 M. This method is successfully applied for the determination of total mercury content in tap water and Yellow River which indicates that the method has a great potential for the routine determination of Hg2+ in environmental samples.

How Do Chinese EFL Learners Perceive Ergatives?

Qi, Mingzhen,강승만 미래영어영문학회 2020 영어영문학 Vol.25 No.1

This paper illustrates some properties of ergatives in Chinese in comparison with English and examines how Chinese EFL learners perceive English ergatives. For our discussion in this paper, we have conducted a survey among 60 Chinese college students. The subjects were asked to judge 5 English ergative constructions and translate them into Chinese. The findings of the survey reveal that the subjects judge them to be grammatical at the rate of 58.6%, which is rather low to our expectation. This is attributable to the nature of some Chinese ergatives exclusively used as such, resisting alternation with transitives. Another finding is that English ergatives are represented as a variety of constructions in Chinese such as ergatives, passives, transitives, ba-constructions, and resultative verb compounds (RVCs) in the order from highest to lowest in their occurrences. We ascribe this to the lack of one-to-one correspondence in ergatives between the two languages.

1930년대 한·중 심리소설 현대 남성 심리구조 비교연구 - 최명익과 스저춘을 중심으로

王明?(Wang Mingzhen),??(Yang Ning) 춘원연구학회 2019 춘원연구학보 Vol.0 No.15

전통관습으로부터 여성 탈출 양상 비교연구

王明眞(Wang Mingzhen) 한국현대소설학회 2016 현대소설연구 Vol.- No.62

Dexamethasone-induced differentiation of pancreatic AR42J cell involves p21waf1/cip1 and MAP kinase pathway

WonSikEum,MingZhenLi,GyeSukSin,SooYoungChoi,Jae-BongPark,JaeYongLee,HyeokYilKwon 생화학분자생물학회 2003 Experimental and molecular medicine Vol.35 No.5

Dexamethasone converts pluripotent pancreatic AR42J cels into exocrine cells expressing diges-tive enzymes. In order to adress molecular me-chanism of this diferentiation, we have investi-gated the role of mitogen-activated protein (MAP) kinase pathway and gene expresions of p21waf1/cip1 and nuclear oncogenes (c-fos and c-myc) during AR42J cell diferentiation. Dexamethasone marked-ly increased the intracellular and secreted amylase contents as wel as its mRNA level. However, cell growth and DNA content were significantly de-creased. With these phenotypic changes, AR42J cells induced transient mRNA expression of p21waf1/cip1gene, which reached maximal level by 6 h and then declined gradualy toward basal state. In contrast to p21waf1/cip1, c-fos gene expres-sion was transiently inhibited by 6 h and then recovered to basal level by 24 h. Increased c-myc expression detected after 3 h, peaked by 12 h, and remained elevated during the rest of observation. Dexamethasone inhibited epidermal growth factor- induced phosphorylation of extracelular signal regulated kinase. Inhibition of MAP kinase pathway by PD98059 resulted in further elevation of the de-xamethasone-induced amylase mRNA and p21waf1/cip1 gene expression. These results sugest that p21waf1/cip1 and nuclear oncogenes are involved in dexamethasone-induced diferentiation and inhi-bition of MAP kinase pathway accelerates the con-version of undiferentiated AR42J cels into am-ylase-secreting exocrine cels.

Effects of 1,25-dihydroxyvitamin D₃ on the differentiation of MC3T3-E1 osteoblast-like cells

Kim, Hyun-Soo,Zheng, Mingzhen,Kim, Do-Kyung,Lee, Won-Pyo,Yu, Sang-Joun,Kim, Byung-Ock Korean Academy of Periodontology 2018 Journal of Periodontal & Implant Science Vol.48 No.1

Purpose: The purpose of this study was to evaluate the effects of 1,25-dihydroxyvitamin $D_3$ on the proliferation, differentiation, and matrix mineralization of MC3T3-E1 osteoblast-like cells in vitro. Methods: MC3T3-E1 osteoblastic cells and 1,25-dihydroxyvitamin $D_3$ were prepared. Cytotoxic effects and osteogenic differentiation were evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, alkaline phosphatase (ALP) activity assay, ALP staining, alizarin red S staining, and reverse transcription-polymerase chain reaction (RT-PCR) for osteogenic differentiation markers such as ALP, collagen type I (Col-I), osteocalcin (OCN), vitamin D receptor (VDR), and glyceraldehyde 3-phosphate dehydrogenase. Results: The MTT assay showed that 1,25-dihydroxyvitamin $D_3$ did not inhibit cell growth and that the rate of cell proliferation was higher than in the positive control group at all concentrations. ALP activity was also higher than in the positive control group at low concentrations of 1,25-dihydroxyvitamin $D_3$ ($10^{-10}$, $10^{-12}$, and $10^{-14}M$). RT-PCR showed that the gene expression levels of ALP, Col-I, OCN, and vitamin D receptor (VDR) were higher at a low concentration of 1,25-dihydroxyvitamin $D_3$ ($10^{-12}M$). Alizarin red S staining after treatment with 1,25-dihydroxyvitamin $D_3$ ($10^{-12}M$) showed no significant differences in the overall degree of calcification. In contrast to the positive control group, formation of bone nodules was induced in the early stages of cell differentiation. Conclusions: We suggest that 1,25-dihydroxyvitamin $D_3$ positively affects cell differentiation and matrix mineralization. Therefore, it may function as a stimulating factor in osteoblastic bone formation and can be used as an additive in bone regeneration treatment.

Computational Bio-Fluid Mechanics

Yang Liu,Weiwei Yan,Mingzhen Lu,Bingmei Fu 한국전산유체공학회 2014 한국전산유체공학회 학술대회논문집 Vol.2014 No.10

It has been found that both circulating blood cells and tumor cells are more easily adherent to curved microvessels than straight ones. In this paper, the hypothesis that tumor cells prefer to adhere at the microvessels with localized shear stresses and their gradients, such as in the curved microvessels, was examined both experimentally and computationally. The fluid dynamics was carried out by the lattice Boltzmann method (LBM), and the cell dynamics was governed by the Newton’s law of translation and rotation. The adhesive dynamics model is involved the effect of receptor-ligand bonds between circulating cells and endothelial cells (ECs). It was found that the wall shear stress/gradient, over a threshold, had significant contribution to tumor cell adhesion by activating or inactivating cell adhesion molecules. Our results elucidated why the tumor cell adhesion prefers to occur at the positive curvature of curved microvessels with very low Reynolds number (in the order of 10<SUP>-2</SUP>) laminar flow. Obstructive sleep apnea (OSA) is a common disorder characterized by partial or complete narrowing of the pharyngeal airway during sleep. The success rate of OSA surgery is very low, CFD is a good alternative tool to understand OSA pathophysiology. We have carried out both LES simulation and experimental measurement in real OSA upper airways for both before and after surgery, and a good agreement is achieved.

Effects of 1,25-dihydroxyvitamin D3 on the differentiation of MC3T3-E1 osteoblast-like cells

Hyun-Soo Kim,Mingzhen Zheng,Do-Kyung Kim,Won-Pyo Lee,Sang-Joun Yu,김병옥 대한치주과학회 2018 Journal of Periodontal & Implant Science Vol.48 No.1

Purpose: The purpose of this study was to evaluate the effects of 1,25-dihydroxyvitamin D3 on the proliferation, differentiation, and matrix mineralization of MC3T3-E1 osteoblast-like cells in vitro. Methods: MC3T3-E1 osteoblastic cells and 1,25-dihydroxyvitamin D3 were prepared. Cytotoxic effects and osteogenic differentiation were evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, alkaline phosphatase (ALP) activity assay, ALP staining, alizarin red S staining, and reverse transcription-polymerase chain reaction (RT-PCR) for osteogenic differentiation markers such as ALP, collagen type I (Col-I), osteocalcin (OCN), vitamin D receptor (VDR), and glyceraldehyde 3-phosphate dehydrogenase. Results: The MTT assay showed that 1,25-dihydroxyvitamin D3 did not inhibit cell growth and that the rate of cell proliferation was higher than in the positive control group at all concentrations. ALP activity was also higher than in the positive control group at low concentrations of 1,25-dihydroxyvitamin D3 (10−10, 10−12, and 10−14 M). RT-PCR showed that the gene expression levels of ALP, Col-I, OCN, and vitamin D receptor (VDR) were higher at a low concentration of 1,25-dihydroxyvitamin D3 (10−12 M). Alizarin red S staining after treatment with 1,25-dihydroxyvitamin D3 (10−12 M) showed no significant differences in the overall degree of calcification. In contrast to the positive control group, formation of bone nodules was induced in the early stages of cell differentiation. Conclusions: We suggest that 1,25-dihydroxyvitamin D3 positively affects cell differentiation and matrix mineralization. Therefore, it may function as a stimulating factor in osteoblastic bone formation and can be used as an additive in bone regeneration treatment.

Low-temperature Tolerance and Saline-Alkali Tolerance of Weedy Rice During Germination Period in Northeastern China

Liu Wenbo,Li Fuxing,Jian Mingzhen,Wu Minggen 제주대학교 아열대농업생명과학연구소 2010 아열대농업생명과학연구지 Vol.26 No.1

Design of h-BN-Filled Cyanate/Epoxy Thermal Conductive Composite with Stable Dielectric Properties

Yangxue Lei,Zengmao Han,Dengxun Ren,Hai Pan,Mingzhen Xu,Xiaobo Liu 한국고분자학회 2018 Macromolecular Research Vol.26 No.7

The thermal conductive cyanate ester/epoxy (CE/AG80) composites with hexagonal boron nitride (h-BN) reinforced were manufactured and investigated. The low and stable dielectric constant/loss of the composites with respect to both frequency (500 Hz-100 kHz) and temperature (50-350 °C) were discussed as functions of the content of h-BN. It was found that the low and stable dielectric constant/ loss of the composites can be maintained in the whole frequency range at room temperature, and the mutations of constant/loss at the frequency of 1 kHz occurred above 280 °C for all of the samples. Moreover, a remarkable enhancement of the thermal conductivity (0.54W/mK a 1.8-fold enhancement) was achieved with the introduction of h-BN and significantly outperformed traditional thermal conductive fillers. The significant improvements of the thermal conductivity of the composites were analyzed by the Agari’s model and the parameters of C1 and C2 were also calculated.