Validation of Methods for Isolation and Culture of Alpaca Melanocytes: A Novel Tool for In vitro Studies of Mechanisms Controlling Coat Color

Bai, Rui,Sen, Aritro,Yu, Zhihui,Yang, Gang,Wang, Haidong,Fan, Ruiwen,Lv, Lihua,Lee, Kyung-Bon,Smith, George W,Dong, Changsheng Asian Australasian Association of Animal Productio 2010 Animal Bioscience Vol.23 No.4

The objective of the present studies was to develop and validate a system for isolation, purification and extended culture of pigment-producing cells in alpaca skin (melanocytes) responsible for coat color and to determine the effect of alpha melanocyte stimulating hormone treatment on mRNA expression for the melanocortin 1 receptor, a key gene involved in coat color regulation in other species. Skin punch biopsies were harvested from the dorsal region of 1-3 yr old alpacas and three different enzyme digestion methods were evaluated for effects on yield of viable cells and attachment in vitro. Greatest cell yields and attachment were obtained following dispersion with dispase II relative to trypsin and trypsin-EDTA treatment. Culture of cells in medium supplemented with basic fibroblast growth factor, bovine pituitary extract, hydrocortisone, insulin, 12-O-tetradecanolphorbol-13-acetate and cholera toxin yielded highly pure populations of melanocytes by passage 3 as confirmed by detection of tyrosinase activity and immunocytochemical localization of melanocyte markers including tyrosinase, S-100 and micropthalmia-associated transcription factor. Abundance of mRNA for tyrosinase, a key enzyme in melanocyte pigment production, was maintained through 10 passages showing preservation of melanocyte phenotypic characteristics with extended culture. To determine hormonal responsiveness of cultured melanocytes and investigate regulation of melanocortin 1 receptor expression, cultured melanocytes were treated with increasing concentrations of ${\alpha}$-melanocyte stimulating hormone. Treatment with ${\alpha}$-melanocyte stimulating hormone increased melanocortin receptor 1 mRNA in a dose dependent fashion. The results demonstrated culture of pure populations of alpaca melanocytes to 10 passages and illustrate the potential utility of such cells for studies of intrinsic and extrinsic regulation of genes controlling pigmentation and coat color in fiber-producing species.

Sensitivity analysis and parameter interval optimization for residual stress in polishing process of GH4169 blisk blade

Xiaojun Lin,Xiaopeng Xin,Rui Yang,Zhaozhao Lei,Luzhou Sun,Bao Yang,Changyou Bai,Yangwei Yan 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.2

Surface integrity has a significant impact on the performance and life cycle of the blisk blade. Residual stress, as one of the important characterization parameters of surface integrity, is closely related to the performance of the aeroengine blisk blade. A certain interval of residual compressive stress can significantly inhibit the generation of microcracks. This paper proposes an optimization method of polishing process parameter interval based on sensitivity analysis. This research studied the effect of polishing parameters of the alumina ACW (abrasive cloth wheel) on the surface residual stress of the GH4169 superalloy blisk blade. Firstly, the experiment was designed by four factors and three levels response surface method, the multiple regression of the experimental data based on Minitab software was used to get a prediction model of polished surface residual stress. And an analysis of variance was performed on the model. Subsequently, the model of relative sensitivity was got based on this model. The sensitivity order of polishing surface residual stress to each polishing parameter was obtained. And the judging method of stable interval and instable interval was put forward. Then, a parameter interval optimization method was proposed, and the optimal interval of process parameters was obtained. Finally, a polishing verification experiment was performed. The results show that: for the polishing of GH4169 superalloy blades, the surface residual stress is most sensitive to the feed rate vf of the ACW, followed by the granularity p and the rotation rate ω, and the compression depth ap is the least sensitive. The optimal interval of polishing process parameters is: the rotation rate ω is [11000 r/min, 11500 r/min], the feed rate vf is [100 mm/min, 200 mm/min], the compression depth ap is [0.6 mm, 1.0 mm], and the granularity p is [400 #, 600 #]. The optimized polishing process parameters can obtain a large and stable surface residual compressive stress, which is helpful to increase fatigue strength of the blisk blade.

Expression and Distribution of the Guanine Nucleotide-binding Protein Subunit Alpha-s in Mice Skin Tissues and Its Association with White and Black Coat Colors

Yin, Zhihong,Zhao, Xin,Wang, Zhun,Li, Zhen,Bai, Rui,Yang, Shanshan,Zhao, Min,Pang, Quanhai Asian Australasian Association of Animal Productio 2016 Animal Bioscience Vol.29 No.10

Guanine nucleotide-binding protein subunit alpha-s ($Gn{\alpha}s$) is a small subunit of the G protein-couple signaling pathway, which is involved in the formation of coat color. The expression level and distribution of $Gn{\alpha}s$ were detected by quantitative real-time-polymerase chain reaction (qPCR), western blot, and immunohistochemistry to investigate the underlying mechanisms of coat color in white and black skin tissues of mice. qPCR and western blot results suggested that $Gn{\alpha}s$ was expressed at significantly higher levels in black mice compared with that of white mice, and transcripts and protein possessed the same expression in both colors. Immunohistochemistry demonstrated $Gn{\alpha}s$ staining in the root sheath and dermal papilla in hair follicle of mice skins. The results indicated that the $Gn{\alpha}s$ gene was expressed in both white and black skin tissues, and the expression level of $Gn{\alpha}s$ in the two types of color was different. Therefore, $Gn{\alpha}s$ may be involved in the coat color formation in mice.

Design of a Class of New Nonlinear Disturbance Observers based on Tracking Differentiators for Uncertain Dynamic Systems

Xiang-Wei Bu,Xiao-Yan Wu,Yong-Xing Chen,Rui-Yang Bai 제어·로봇·시스템학회 2015 International Journal of Control, Automation, and Vol.13 No.3

The main contribution of this paper is to present a general design method of new nonlinear disturbance observer (NDO) based on tracking differentiator (TD) for uncertain dynamic system. The stability and convergence of the proposed NDO can be guaranteed by TD. This new NDO can be used to estimate many types of uncertain disturbances, and can overcome the disadvantages of existing NDOs that need the priori information concerning the upper and lower bounds of the disturbance and its ith derivative’s Lipschitz upper bound. It can be also applied in uncertain dynamic system for various purposes such as disturbance estimate and compensation, solving the problem of control input constraint, and reducing even eliminating chattering of control input. Simulation results are presented to show the effectiveness of the developed NDO.

Systemic Inflammatory Biomarkers, Especially Fibrinogen to Albumin Ratio, Predict Prognosis in Patients with Pancreatic Cancer

Lin Fang,Fei-Hu Yan,Chao Liu,Jing Chen,Dan Wang,Chun-Hui Zhang,Chang-Jie Lou,Jie Lian,Yang Yao,Bo-Jun Wang,Rui-Yang Li,Shu-Ling Han,Yi-Bing Bai,Jia-Ni Yang,Zhi-Wei Li,Yan-Qiao Zhang 대한암학회 2021 Cancer Research and Treatment Vol.53 No.1

Purpose Systemic inflammatory response is a critical factor that promotes the initiation and metastasis of malignancies including pancreatic cancer (PC). This study was designed to determine and compare the prognostic value of neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), monocyte-to-lymphocyte ratio (MLR), and fibrinogen-to-albumin ratio (FAR) in resectable PC and locally advanced or metastatic PC. Materials and Methods Three hundred fifty-three patients with resectable PC and 807 patients with locally advan-ced or metastatic PC were recruited in this study. These patients were classified into a training set (n=758) and a validation set (n=402). Kaplan-Meier survival plots and Cox proportional hazards regression models were used to analyze prognosis. Results Overall survival (OS) was significantly better for patients with resectable PC with low preoperative PLR (p=0.048) and MLR (p=0.027). Low FAR, MLR, NLR (p < 0.001), and PLR (p=0.003) were significantly associated with decreased risk of death for locally advanced or metastatic PC patients. FAR (hazard ratio [HR], 1.522; 95% confidential interval [CI], 1.261 to 1.837; p < 0.001) and MLR (HR, 1.248; 95% CI, 1.017 to 1.532; p=0.034) were independent prognostic factors for locally advanced or metastatic PC. Conclusion The prognostic roles of FAR, MLR, NLR, and PLR in resectable PC and locally advanced or metastatic PC were different. FAR showed the most prognostic power in locally advanced or metastatic PC. Low FAR was positively correlated with OS in locally advanced or metastatic PC, which could be used to predict the prognosis.