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Search Results: 1 - 10 of 59865 matches for " Guo-Ying Qian "
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Inhibitory Effect of Phthalic Acid on Tyrosinase: The Mixed-Type Inhibition and Docking Simulations
Shang-Jun Yin,Yue-Xiu Si,Guo-Ying Qian
Enzyme Research , 2011, DOI: 10.4061/2011/294724
Abstract: Tyrosinase inhibition studies are needed due to the medicinal applications such as hyperpigmentation. For probing effective inhibitors of tyrosinase, a combination of computational prediction and enzymatic assay via kinetics was important. We predicted the 3D structure of tyrosinase, used a docking algorithm to simulate binding between tyrosinase and phthalic acid (PA), and studied the reversible inhibition of tyrosinase by PA. PA inhibited tyrosinase in a mixed-type manner with a =65.84±1.10 mM. Measurements of intrinsic and ANS-binding fluorescences showed that PA induced changes in the active site structure via indirect binding. Simulation was successful (binding energies for Dock6.3=?27.22 and AutoDock4.2=?0.97 kcal/mol), suggesting that PA interacts with LEU73 residue that is predicted commonly by both programs. The present study suggested that the strategy of predicting tyrosinase inhibition based on hydroxyl groups and orientation may prove useful for screening of potential tyrosinase inhibitors.
Studies on the Formation of Pearl-sac in Vitro of Epithelial Cells and Tissue from Mantle

CHEN Yong-fu,QIAN Guo-ying,

水生态学杂志 , 2009,
Abstract: 通过对三角帆蚌外套膜上皮组织块培养和上皮细胞培养存包硬核、无包硬核的情况下的钙代谢进行比较分析,用偏光显微镜观察.结果发现,外套膜上皮组织块、上皮细胞在有硬核时与埘照的无硬核培养钙含量无明显差别,外套膜组织块经培养迁移和增值,能形成珍珠囊的上皮细胞,其结缔组织细胞共同围绕珍珠囊上皮细胞组成完整的珍珠囊.偏光显微镜下能观察到舣折射现象,表明产生由碳酸钙结晶形成的片层叠加构成珍珠质.该研究进一步探讨了体外培育珍珠(试管珍珠)的技术,为试管珍珠的研究提供了实验依据.
Guo-Ying Zhang
Acta Crystallographica Section E , 2009, DOI: 10.1107/s1600536809030554
Abstract: In the title compound, C5H7N3OS2, inversion dimers linked by pairs of N—H...N hydrogen bonds occur, forming R22(8) ring motifs. These dimers are arranged into chains via intermolecular C—H...O hydrogen bonds between the methylsulfanyl groups and the O atoms of the carbonyl groups. The acetamido-1,3,4-thiodiazole unit is essentially planar [r.m.s. deviation 0.045 (8) ].
Stable de Sitter critical points of the cosmology in quadratic gravitation with torsion
Guo-Ying Qi
Physics , 2011,
Abstract: Homogeneous isotropic spatial flat cosmological models with two torsion functions in vacuum are built and investigated in the framework of de Sitter gauge theory of gravity. It is shown that by certain choices of parameters of gravitational Lagrangian the cosmological equations have some exact constant solutions that turn out to be stable de Sitter critical points of dynamical systems and can explain observable acceleration of cosmological expansion. The role of the space-time torsion provoking the acceleration of cosmological expansion is shown.
Computational Prediction of Protein-Protein Interactions of Human Tyrosinase
Su-Fang Wang,Sangho Oh,Yue-Xiu Si,Zhi-Jiang Wang,Hong-Yan Han,Jinhyuk Lee,Guo-Ying Qian
Enzyme Research , 2012, DOI: 10.1155/2012/192867
Abstract: The various studies on tyrosinase have recently gained the attention of researchers due to their potential application values and the biological functions. In this study, we predicted the 3D structure of human tyrosinase and simulated the protein-protein interactions between tyrosinase and three binding partners, four and half LIM domains 2 (FHL2), cytochrome b-245 alpha polypeptide (CYBA), and RNA-binding motif protein 9 (RBM9). Our interaction simulations showed significant binding energy scores of ?595.3?kcal/mol for FHL2, ?859.1?kcal/mol for CYBA, and ?821.3?kcal/mol for RBM9. We also investigated the residues of each protein facing toward the predicted site of interaction with tyrosinase. Our computational predictions will be useful for elucidating the protein-protein interactions of tyrosinase and studying its binding mechanisms. 1. Introduction Tyrosinase (EC is ubiquitously distributed in organisms and is a critical enzyme involved in melanin production, with multiple catalytic functions in pigment production [1–3]. Tyrosinase mutations are directly linked to pigmentation disorders in mammals [4, 5] and can cause a browning effect in vegetables [6, 7]. In addition, tyrosinase participates in cuticle formation in insects [8, 9]. In mammals, tyrosinase is a bifunctional enzyme that first converts tyrosine to DOPA and then to DOPA quinone, which is further cyclized and oxidized to produce melanin pigments [10]. The human tyrosinase protein contains two Cu2+-binding sites, two cysteine rich regions, a signal peptide region, a transmembrane anchor domain, and an EGF motif [11]. Two Cu2+ ions in the active site of tyrosinase are coordinated by three histidine residues each and are essential for the enzyme’s catalytic activity [12]. Furthermore, the presence of Cu2+ in the active site of tyrosinase is observed across numerous organisms [13]. Therefore, chelation of tyrosinase Cu2+ by synthetic compounds or agents from natural sources has been targeted as a way to block tyrosinase catalysis for medicinal purposes, darkening problems in agricultural products, and cosmetic interests [14, 15]. As the crystallographic structure of tyrosinase has been gradually elucidated, insights into its catalytic mechanisms and active site have also been revealed [16–18]. However, while the catalytic mechanism of tyrosinase-mediated melanin pigment production has been well studied, the relationship between tyrosinase enzyme activity and protein interactions has not been fully elucidated, despite several reports of interacting proteins for tyrosinase [19–22].
Supervised image segmentation method based on tree-structured Markov random field in wavelet domain

LIU Guo-Ying,WANG Ai-Min,CHEN Rong-Yuan,QIN Qian-Qing,

红外与毫米波学报 , 2011,
Abstract: 定义在单一空间分辨率上的树结构马尔可夫场(Tree-Structured Markov Random Field,TS-MRF)模型能够表达图像的分层结构信息,但难以描述图像的非平稳性。针对该问题,提出小波域的TS-MRF图像建模方法—WTS-MRF模型。按照图像分类层次树的结构形式,该模型将一系列的MRF嵌套定义在多分辨率的小波域中:每一个树节点对应于定义在不同分辨率上的一个MRF集合,并通过条件概率的形式将相邻分辨率上的MRF间的作用关系考虑进来;同时相同分辨率的父子节点对应的MRF通过区域约束嵌套定义。基于WTS-MRF模型,给出了一个监督图像分割的递归算法,通过给定的分类层次树表示先验信息,并通过训练数据给出叶子节点在各分辨率上的统计参数。它在尺度内和尺度间两个层次上进行递归:首先,在最低分辨率上执行尺度内递归,即采用ICM算法从树的根节点到叶子节点依次对MRF进行递归估计;然后执行尺度间递归,即在相邻的更高分辨率尺度上,通过直接投影的方式依次获取每一MRF的初始估计,并采用ICM算法递归优化;最后,原始分辨率的MRF估计完成,获取最终分割结果。两组实验从视觉效果和定量指标(整体分类精度和Kappa系数)两个方面验证了算法的有效性。
Research advances in the mechanism of osteoarthritis caused by the mechanical instability

JI An-qi
, DENG Guo-ying, WANG Qiu-gen, WANG Qian

- , 2017, DOI: 10.3969/j.issn.1674-8115.2017.04.028
Abstract: 骨关节炎是一种常见的关节软骨退行性疾病,力学失稳态是骨关节炎发病的较为经典的原因。力学失稳态可以通过直接损伤、诱导细胞凋亡和刺激炎症因子生成,来减少软骨细胞数量和破坏软骨细胞外基质,导致基质中的Ⅱ型胶原蛋白和蛋白多糖减少,使软骨发生退变,长期作用可导致骨关节炎的发生。因此,了解力学失稳态如何导致骨关节炎发生能更好地从力学角度改善骨关节炎的病程。
: Osteoarthritis is a common articular cartilage degenerative disease and the main cause is mechanical instability. The mechanical instability can reduce the number of chondrocytes and destroy extracellular matrix through direct injury, inducing cell apoptosis, and stimulating the production of inflammatory factors, leading to decrease of matrix type II collagen and proteoglycan and degeneration of cartilage. Long-term cartilage degeneration can result in osteoarthritis. Therefore, understanding how mechanical instability leads to the incidence of osteoarthritis can better improve the course of osteoarthritis from the perspective of mechanics
A exact de Sitter cosmological solution of quadratic gravitation with torsion
Guo-Ying Qi,Yongxin Guo
Physics , 2011,
Abstract: A exact de Sitter-like cosmological solution of quadratic gravitation with torsion has been found. In the limit of constant energy and pressure, it becomes a exact de Sitter spacetime. It exists in a wide class of quadratic gravity theories and is the same in vacuum for all the models in this class, no matter how the coefficients of the quadratic terms in the Lagrangian are. It describes an accelerating universe and gives a cosmological constant which is of the order of magnitude of the observed value. In vacuum the universe is a de Sitter spacetime without torsion. When matter presents, however, the spacetime is equipped with curvature as well as torsion. In other wards torsion can be generated by the energy-momentum of matter (energy and pressure).
Structure of $X_b$ from line shape analysis
Yue Ma,Guo-Ying Chen
Physics , 2015,
Abstract: We study the production line shape of $B^\ast\bar B$ near threshold, where the $B^\ast \bar B$ pair comes from the resonance $X_b$. Our study shows that the line shape depends sensitively on the binding energy and the probability of finding an elementary state in the physical bound state. Both of the two parameters are crucial to identify the structure of $X_b$. Therefore, the line shape measurement can shed light on the structure of $X_b$.
Towards -Induced Manganese-Containing Superoxide Dismutase Inactivation and Conformational Changes: An Integrating Study with Docking Simulations
Jiang-Liu Yang,Shang-Jun Yin,Yue-Xiu Si,Zhi-Rong Lü,Xiangrong Shao,Daeui Park,Hae Young Chung,Hai-Meng Zhou,Guo-Ying Qian,Zi-Ping Zhang
Enzyme Research , 2011, DOI: 10.4061/2011/307464
Abstract: Superoxide dismutase (SOD, EC plays an important antioxidant defense role in skins exposed to oxygen. We studied the inhibitory effects of Al3+ on the activity and conformation of manganese-containing SOD (Mn-SOD). Mn-SOD was significantly inactivated by Al3+ in a dose-dependent manner. The kinetic studies showed that Al3+ inactivated Mn-SOD follows the first-order reaction. Al3+ increased the degree of secondary structure of Mn-SOD and also disrupted the tertiary structure of Mn-SOD, which directly resulted in enzyme inactivation. We further simulated the docking between Mn-SOD and Al3+ (binding energy for Dock 6.3: ?14.07?kcal/mol) and suggested that ASP152 and GLU157 residues were predicted to interact with Al3+, which are not located in the Mn-contained active site. Our results provide insight into the inactivation of Mn-SOD during unfolding in the presence of Al3+ and allow us to describe a ligand binding via inhibition kinetics combined with the computational prediction. 1. Introduction Superoxide dismutases (SOD, EC are a class of enzymes that catalyze the dismutation of superoxide into oxygen and hydrogen peroxide [1–3]. They play an important antioxidant defense role in skins exposed to oxygen. In this regard, for the treatment of systemic inflammatory diseases including skin ulcer lesions, the topical application of free Mn-SOD or Cu, Zn-SOD extracted from bovine, bacterial, and other species was dramatically effective in skin lesions [4]. It has been reported that significant increase in the levels of SOD occurs in vitiligo patients due to the increased oxidative stress [5]. The involvement of oxidative stress in chronic idiopathic urticaria associated with SOD was also reported [6]: the activity of SOD was markedly increased in lesional skin as compared with skin of healthy subjects, indicating that oxidative stress is crucially involved in chronic idiopathic urticaria and suggesting that oxidative stress is secondary to the development of inflammation. The earlier reports [7, 8] suggested that the activity of activator protein-1, which is associated with tumor promotion, was reduced in Mn-SOD transgenic mice overexpressing Mn-SOD in the skin, suggesting that Mn-SOD reduced tumor incidence by suppressing activator protein-1 activation. The mechanism of Mn-SOD catalysis is very important, and the mechanism therefore needs to be investigated from different sources using various kinetic methods. The information regarding the tertiary structure and the structural integrity of the active site of Mn-SOD is little known and in
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