THE LOCAL TIME OF THE LINEAR SELF-ATTRACTING DIFFUSION DRIVEN BY WEIGHTED FRACTIONAL BROWNIAN MOTION

Chen, Qin,Shen, Guangjun,Wang, Qingbo Korean Mathematical Society 2020 대한수학회보 Vol.57 No.3

In this paper, we introduce the linear self-attracting diffusion driven by a weighted fractional Brownian motion with weighting exponent a > -1 and Hurst index |b| < a + 1, 0 < b < 1, which is analogous to the linear fractional self-attracting diffusion. For the 1-dimensional process we study its convergence and the corresponding weighted local time. As a related problem, we also obtain the renormalized intersection local time exists in L² if max{a₁ + b₁, a₂ + b₂} < 0.

Effects of Daidzein on mRNA Expression of Bone Morphogenetic Protein Receptor Type I and II Genes in the Ovine Granulosa Cells

Chen, A Qin,Xu, Zi Rong,Yu, Song Dong,Yang, Zhi Gang Asian Australasian Association of Animal Productio 2010 Animal Bioscience Vol.23 No.3

Daidzein, a natural isoflavonoid phytoestrogen, structurally resembles estradiol (E2) and possesses estrogenic activity. This study was designed to test the hypothesis that daidzein may mimic the effects of E2 on ovine follicle development by regulation of the mRNA expression of bone morphogenetic protein receptor genes and thereby influence the reproductive system. Granulosa cells were cultured in serum-free McCoy's 5A medium with and without supplementation of daidzein. Results showed that daidzein (10-100 ng/ml) significantly increased the proliferation of ovine granulosa cells (p<0.05), but inhibited the growth of granulosa cells at a dose of 1,000 ng/ml (p<0.01). Daidzein inhibited progesterone production in a dose dependent manner; however, it did not affect estradiol production by granulosa cells. We also investigated the effects of daidzein on BMPRII, BMPRIB and ALK-5 mRNA expression in ovine granulosa cells by quantitative real-time PCR. Treatment of granulosa cells with daidzein increased significantly expression of these genes at 10-100 ng/ml. Thus, these data suggested that a low concentration of daidzein (10-100 ng/ml) had a direct stimulatory effect on ovine granulosa cells while a high concentration was toxic.

The local time of the linear self-attracting diffusion driven by weighted fractional Brownian motion

Qin Chen,Guangjun Shen,Qingbo Wang 대한수학회 2020 대한수학회보 Vol.57 No.3

In this paper, we introduce the linear self-attracting diffusion driven by a weighted fractional Brownian motion with weighting exponent $a>-1$ and Hurst index $|b|<a+1,0<b<1$, which is analogous to the linear fractional self-attracting diffusion. For the 1-dimensional process we study its convergence and the corresponding weighted local time. As a related problem, we also obtain the renormalized intersection local time exists in $L^2$ if $\text{max}\{a_1+b_1,a_2+b_2\}<0$.

The transcription factor PjERF1 enhances the biosynthesis of triterpenoid saponins in Panax japonicus

Chen Qin,Yu Yilin,Zhang Xiang,Zhao Ren,Zhang Jinyu,Liu Diqiu,Cui Xiuming,Ge Feng 한국식물생명공학회 2021 Plant biotechnology reports Vol.15 No.5

The ERF-type transcription factors (TFs) play vital roles in plant secondary metabolism. ERF TFs simultaneously regulate the expression levels of key enzyme genes involved in the biosynthesis of secondary metabolites due to its “multi-point control” function. In this study, one gene of ERF TFs from Panax japonicus (PjERF1) was cloned. The open reading frame of PjERF1 was 801 bp and encoded 266 amino acids. Phylogenetic analysis showed that PjERF1 belonged to ERF subfamily with a typical conserved domain. Subcellular localization found that PjERF1 protein might be located in eukaryotic cell nucleus. Yeast one-hybrid assay demonstrated that PjERF1 could bind to the promoters of PjβAS, PjCAS, and PjSE specifically and regulate the expression levels of such key enzyme genes involved in the triterpene saponins biosynthesis. Therefore, in the PjERF1 overexpression cell lines, the expression levels of some key enzyme genes involved in the triterpenoid saponins biosynthesis were significantly increased compared with those in non-transgenic cell line. As a result of it, the biosynthesis of chikusetsusaponin IV and IVa, and other ginsenosides (Rd, Rb1, Re, and R0) were also promoted in the PjERF1 over- expression cell lines. This study indicated that PjERF1 could regulate the biosynthesis of saponins in P. japonicus through controlling the expression levels of key enzyme genes related to the biosynthesis of triterpenoid saponins.

Behavior of improved through-diaphragm connection to square tubular column under tensile loading

Qin, Ying,Zhang, Jing-Chen,Shi, Peng,Chen, Yi-Fu,Xu, Yao-Han,Shi, Zuo-Zheng 국제구조공학회 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.68 No.4

Square tubular columns are commonly used in moment resisting frames, while through-diaphragm connection is the most typical configuration detail to connect the H-shaped beam to the column. However, brittle fracture normally occurs at the complete joint penetration weld between the beam flange and the through-diaphragm due to the stress concentration caused by the geometrical discontinuity. Accordingly, three improved types of through-diaphragm are presented in this paper to provide smooth force flow path comparing to that of conventional connections. Tensile tests were conducted on four specimens and the results were analyzed in terms of failure modes, load-displacement response, yield and ultimate capacity, and initial stiffness. Furthermore, strain distributions on the through-diaphragm, the beam flange plate, and the column face were comprehensively evaluated and discussed. It was found that all the proposed three types of improved through-diaphragm connections were able to reduce the stress concentration in the welds between the beam flange and the through-diaphragm. Furthermore, the stress distribution in connection with longer tapered through-diaphragm was more uniform.

pH-dependent release of platycodin mitigates its gastrointestinal mucosa irritation after oral administration in rats

Qin Chen,Wen-Wen Yang,Pan Shen,Qing-Ri Cao,Beom-Jin Lee,Jing-Hao Cui 대한약학회 2016 Archives of Pharmacal Research Vol.39 No.6

The present study aimed to evaluate the gastrointestinalmucosa irritation of three platycodin formulations. Platycodin-loaded core pellets were prepared viaextrusion–spheronization method and coated withEudragit L100-55 (L100) or Eudragit S100 (S100) forpH-dependent release. The release of platycodin D fromcoated pellets exhibited pH dependent release profiles. Thepharmacokinetic study in rats showed that Tmax of thecoated pellets were prolonged as compared to that of uncoatedpellets. The S100-coated pellets possess a lowerCmax and decreased AUC0–24h as compared to the L100-coated and uncoated pellets. Hematoxylin-eosin stainingand nuclear factor Kappa B (NF-jB) measurement werecarried out to observe the gastrointestinal mucosa irritations. The results revealed that the irritations of platycodinon the upper gastrointestinal mucosa are dose-dependent. However, no obvious irritation effect on the gastrointestinaltissues of rats was detected after oral administration ofthe coated pellets. In addition, the amount of NF-jB in thestomach of rats treated with the uncoated pellets was aboutfivefold higher as compared to that of the coated pellets. Insummary, the L100-coated platycodin pellets exhibitedhigher oral bioavailability and less gastrointestinal mucosairritations as compared to the other two formulations.

Amphiregulin secreted by cartilage endplate stem cells inhibits intervertebral disk degeneration and TNF-α production via PI3K/AKT and ERK1/2 signaling pathways

Chen Qin,Wu Yaohong,Zhong Mingliang,Xu Chanhua,Chen Rongchun,Liu Ning 대한독성 유전단백체 학회 2023 Molecular & cellular toxicology Vol.19 No.2

Background Intervertebral disk degeneration (IDD) is a common orthopedic disorder, and nucleus pulposus cells (NPCs) serve to stabilize the intervertebral disk. Objective This study was implemented to explore the protective eff ect of endplate stem cells (EPSCs) on IDD. NPCs and EPSCs were isolated from rats and tert -Butyl peroxide (TBHP) was used to treat NPCs and simulate IDD. EPSC-derived conditioned medium (CM) was collected and mixed with a culture medium at diff erent proportions, which was then used to treat NPCs. SOD assay was employed to examine the oxidative stress level in the NPCs. To assess apoptosis and caspase-3 activity, fl ow cytometry and western blots for cleaved PARP1 and BAX were carried out. The mRNA expression levels of diff erent genes were detected by quantitative real-time polymerase chain reaction. Furthermore, the concentrations of amphiregulin (Areg) and infl ammatory factors were measured with ELISA kits and cell signaling pathways were evaluated using western blotting. Results Following TBHP treatment, caspase-3 activity in the NPCs increased. However, exposing TBHP-induced NPCs to the EPSC-derived CM reduced oxidative stress, caspase-3 activity, cell apoptosis, fi brotic response, and cytokine production. Additionally, the EPSC-derived CM contained a higher concentration of Areg compared to that in the NPCs. Furthermore, Areg decreased oxidative stress, cell apoptosis, fi brosis, and infl ammation via both PI3K/AKT and ERK1/2 signaling pathways. Conclusion ECSCs reduce NPC apoptosis, oxidative stress, production of infl ammatory factors, and fi brotic response via the release of Areg. Moreover, Areg can exert these protective eff ects on NPCs via PI3K/AKT and ERK1/2 signaling pathways.

Finite-time H∞ Control for Switched Systems with Time-varying Delay using Delta Operator Approach

Chen Qin,Zhengrong Xiang,Hamid Reza Karimi 제어·로봇·시스템학회 2014 International Journal of Control, Automation, and Vol.12 No.6

Finite-time H∞ control for switched systems with time-varying delay using delta operator approach is investigated in this paper. Firstly, by using the average dwell time approach and delta operator theory, sufficient conditions for H∞ finite-time boundedness of the underlying systems are derived. Then a state feedback controller is proposed such that the resulting closed-loop system is H∞ finite-time bounded. All the obtained results are formulated in terms of linear matrix inequalities (LMIs). Finally, an example is presented to show the validity of the proposed results.

Enhanced mechanical properties and interface structure characterization of W-La₂O₃ alloy designed by an innovative combustion-based approach

Chen, Pengqi,Xu, Xian,Wei, Bangzheng,Chen, Jiayu,Qin, Yongqiang,Cheng, Jigui Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.5

Oxide dispersion strengthening (ODS) tungsten alloys are highly desirable in irradiation applications. However, how to improve the properties of ODS-tungsten alloys efficiently has been worth studying for a long time. Here we report a nanostructuring approach that achieves W-La₂O₃ alloy with a high level of flexural strength and Vickers hardness at room temperature, which have the maximum value of 581 MPa and 703 Hv, respectively. This method named solution combustion synthesis (SCS) can generate 30 nm coating structures W-La₂O₃ composite powders by using Keggin-type structural polyoxometalates as raw materials in a fast and low-cost process. The composite powder can be fabricated to W-La₂O₃ alloy with an optimal microstructure of submicrometric W grains coexisting with nanometric oxide particles in the grain interior, and a stability interface structure of grain boundaries (GBs) by forming transition zones. The method can be used to prepare new ODS alloys with excellent properties in the future.

Determination of ginsenosides in Asian and American ginsengs by liquid chromatography-quadrupole/time-of-flight MS: assessing variations based on morphological characteristics

Chen, Yujie,Zhao, Zhongzhen,Chen, Hubiao,Brand, Eric,Yi, Tao,Qin, Minjian,Liang, Zhitao The Korean Society of Ginseng 2017 Journal of Ginseng Research Vol.41 No.1

Background: Asian ginseng and American ginseng are functional foods that share a close genetic relationship and are well-known worldwide. This article aims to investigate the correlation between morphological characteristics and the inherent quality of Asian and American ginsengs. Methods: In this study, an ultra-HPLC-quadrupole/time-of-flight MS (UHPLC-Q/TOF-MS) method was established for the quantitative analysis of 45 ginseng samples. The method developed for determination was precise and accurate. Results: The results showed that Asian ginseng samples with the same growing time (with the same or similar number of stem scars) that had a thinner main root, a longer rhizome and more branch roots contained greater amounts of ginsenosides. For American ginseng, two tendencies were observed in the relationship between the diameter of the main root and contents of ginsenosides. One tendency was that samples with thinner main roots tended to contain higher levels of ginsenosides, which was observed in the samples sold under the commercial name pao-shen. Another tendency was that samples with thicker main roots contained higher contents of ginsenosides, which was observed in the samples sold under the commercial name pao-mian, as well as in samples of American ginseng cultivated in Jilin, China. Conclusion: An approach using ultra-HPLC-quadrupole/time-of-flight MS was successfully established to link morphology and active components for evaluating the quality of Asian and American ginsengs. Clear correlation between visible morphological features and quality of Asian and American ginsengs was found. People can see the difference; this means consumers and vendors can evaluate ginseng by themselves.