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Search Results: 1 - 10 of 86238 matches for " Jian Yu "
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Crystallization Kinetics of Poly(3-hydroxybutyrate) Granules in Different Environmental Conditions  [PDF]
Michael Porter, Jian Yu
Journal of Biomaterials and Nanobiotechnology (JBNB) , 2011, DOI: 10.4236/jbnb.2011.23037
Abstract: Poly(3-hydroxybutyrate) (PHB) is a natural biopolyester accumulated in microbial cells as tiny amorphous granules. The nano- micro-particles have a variety of potential applications and behave differently in different environments. In this work, the in situ crystallization of native PHB granules was investigated under different environmental conditions. The isothermal crystallization kinetics of the granules was shown to follow Avrami’s equation. The model parameter describing crystal growth is a function of temperature or pH and estimated from in situ crystallization measurements with attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. Empirical equations describing crystal growth are derived for the parameter values. PHB granules heated at 80-140°C in acidic solution (pH 2) up to 4 hr showed an increase in crystallinity from about 5% to 35% and moderate particle aggregation. PHB granules suspended in alkaline solutions (pH 9-12) at room temperature up to 4 hr showed an increase in crystallinity up to 45% and very little particle aggregation. It was found that the amorphousness of PHB granules in vivo is stabilized by water, lipids and proteins. Upon removal of these impurities, partial crystallization is induced which may inhibit extensive particle aggregation.
Apply GPCA to Motion Segmentation  [PDF]
Hongchuan Yu, Jian Jun Zhang
Journal of Intelligent Learning Systems and Applications (JILSA) , 2011, DOI: 10.4236/jilsa.2011.31006
Abstract: In this paper, we present a motion segmentation approach based on the subspace segmentation technique, the genera-lized PCA. By incorporating the cues from the neighborhood of intensity edges of images, motion segmentation is solved under an algebra framework. Our main contribution is to propose a post-processing procedure, which can detect the boundaries of motion layers and further determine the layer ordering. Test results on real imagery have confirmed the validity of our method.
catena-Poly[[diaqua(1H-imidazo[4,5-f][1,10]phenanthroline)cobalt(II)]-μ-sulfato]
Jian Yu
Acta Crystallographica Section E , 2009, DOI: 10.1107/s1600536809016419
Abstract: The CoII ion in the title complex, [Co(SO4)(C13H8N4)(H2O)2]n, has a slightly distorted octahedral coordination environment formed by two O atoms from two symmetry-related bridging sulfate ligands, two N atoms from a bis-chelating 1H-imidazo[4,5-f][1,10]phenanthroline (IPL) ligand and two O atoms from coordinated water molecules. The bridging sulfate ligands connect CoII ions to form a one-dimensional chain along the b-axis direction. In the crystal structure, intermolecular O—H...O, O—H...N and N—H...O hydrogen bonds link the chains into a three-dimensional network.
catena-Poly[[[di-μ2-hydroxido-bis[(di-2-pyridylamine)nickel(II)]]-μ-fumarato] dihydrate]
Jian Yu
Acta Crystallographica Section E , 2009, DOI: 10.1107/s1600536809013580
Abstract: The NiII ion in the one-dimensional title complex, {[Ni2(C4H2O4)(OH)2(C10H9N3)2]·2H2O}n, has a distorted square-pyramidal coordination environment formed by three O atoms from two bridging hydroxide groups and one carboxylate group of the fumarate ligand and two pyridine N atoms from a di-2-pyridylamine (dpa) ligand. Two hydroxide groups link adjacent metal centers, forming a centrosymmetric four-membered [Ni2(OH)2] ring. In the crystal structure, the H atoms of the bridging hydroxide groups form intermolecular hydrogen bonds to both water molecules. These are further linked to the uncoordinated O atoms of the carboxylate groups and the NH group of a dpa ligand to generate a three-dimensional network from the chains of the coordination polymer.
PUMA Kills Stem Cells to Stall Cancer?
Jian Yu
Molecular and Cellular Pharmacology , 2009,
Abstract: Apoptosis evasion is a hallmark of human cancer. PUMA is a BH3-only Bcl-2 family protein that mediates both p53-dependent and independent apoptosis. However, its role in tumor suppression had not been well established. Our recent work provides direct evidence that PUMA plays an important role in suppressing intestinal tumorigenesis in two mouse models including (i) the azoxymethane (AOM)/dextran sulfate sodium salt (DSS)-treated mice and (ii) APCMin/+ mice. The activities of PUMA appeared to be in the intestinal stem cells, and involve both p53-dependent response to DNA damage, and p53-independent mechanisms triggered by inflammation. Our data suggest that the interplay between different apoptotic pathways in intestinal stem cells underlie the initiation of intestinal carcinogenesis, and should be considered in the context of cancer prevention and therapy.
Communication: Words and Conceptual Systems
Jian Yu
Computer Science , 2015,
Abstract: Words (phrases or symbols) play a key role in human life. Word (phrase or symbol) representation is the fundamental problem for knowledge representation and understanding. A word (phrase or symbol) usually represents a name of a category. However, it is always a challenge that how to represent a category can make it easily understood. In this paper, a new representation for a category is discussed, which can be considered a generalization of classic set. In order to reduce representation complexity, the economy principle of category representation is proposed. The proposed category representation provides a powerful tool for analyzing conceptual systems, relations between words, communication, knowledge, situations. More specifically, the conceptual system, word relations and communication are mathematically defined and classified such as ideal conceptual system, perfect communication and so on; relation between words and sentences is also studied, which shows that knowledge are words. Furthermore, how conceptual systems and words depend on situations is presented, and how truth is defined is also discussed.
Generalized Categorization Axioms
Jian Yu
Computer Science , 2015,
Abstract: Categorization axioms have been proposed to axiomatizing clustering results, which offers a hint of bridging the difference between human recognition system and machine learning through an intuitive observation: an object should be assigned to its most similar category. However, categorization axioms cannot be generalized into a general machine learning system as they have two shortcomings: one is that categorization can not explain why the error rate of classification methods cannot reach zero, the other is that categorization axioms become trivial when the number of categories becomes one. In order to generalize categorization axioms into general cases, categorization input and categorization output are reinterpreted by inner and outer category representation. According to the categorization reinterpretation, two category representation axioms are presented. Category representation axioms and categorization axioms can be combined into a generalized categorization axiomatic framework, which accurately delimit the theoretical categorization constraints and overcome the shortcoming of categorization axioms. The proposed axiomatic framework not only discuses categorization test issue but also reinterprets many results in machine learning in a unified way, such as dimensionality reduction,density estimation, regression, clustering and classification.
Flocking Control of a Group of Agents Using a Fuzzy-Logic-Based Attractive/Repulsive Function  [PDF]
Hui Yu, Jigui Jian, Yanjun Shen
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2010, DOI: 10.4236/ijcns.2010.36076
Abstract: In this study, a novel procedure is presented for control and analysis of a group of autonomous agents with point mass dynamics achieving flocking motion by using a fuzzy-logic-based attractive/repulsive function. Two cooperative control laws are proposed for a group of autonomous agents to achieve flocking formations related to two different centers (mass center and geometric center) of the flock. The first one is designed for flocking motion guided at mass center and the other for geometric center. A virtual agent is introduced to represent a group objective for tracking purposes. Smooth graph Laplacian is introduced to overcome the difficulties in theoretical analysis. A new fuzzy-logic-based attractive/repulsive function is proposed for separation and cohesion control among agents. The theoretical results are presented to indicate the stability (separation, collision avoidance and velocity matching) of the control systems. Finally, simulation example is demonstrated to validate the theoretical results.
Logistic Mapping-Based Complex Network Modeling  [PDF]
Xiaoling Yu, Zhen Jia, Xiangguo Jian
Applied Mathematics (AM) , 2013, DOI: 10.4236/am.2013.411210
Abstract:

In this paper, a new topological approach for studying an integer sequence constructed from Logistic mapping is proposed. By evenly segmenting [0,1] into N non-overlapping subintervals which is marked as \"\", representing the nodes identities, a network is constructed for analysis. Wherein the undirected edges symbolize their relation of adjacency in an integer sequence obtained from the Logistic mapping and the top integral function. By observation, we find that nodes’ degree changes with different values of \"\" instead of the initial value—X0, and the degree distribution presents the characteristics of scale free network, presenting power law distribution. The results presented in this paper provide some insight into degree distribution of the network constructed from integer sequence that may help better understanding of the nature of Logistic mapping.

Progress and prospect for high temperature single-phased magnetic ferroelectrics
Jian Yu,JunHao Chu
Chinese Science Bulletin , 2008, DOI: 10.1007/s11434-008-0308-3
Abstract: Magnetic ferroelectrics are one of the most important functional materials. The present bottleneck limiting applications of them is lacking of high-temperature single-phased ferromagnetic-ferroelectric multiferroics with strong magnetoelectric coupling effect. Here, those progresses of the mechanism for coexistence of ferroelectric and magnetic order, experimental and theoretical studies on single-phased magnetic ferroelectrics, and the relationship between magnetic structure and crystal symmetry are summarized. With examples of BiFeO3, BiMnO3 and Bi2FeCrO6, the difficulties encountered in this field are analyzed. At last, some prospects to develop high-temperature single-phased ferromagnetic-ferroelectric multiferroics are also presented.
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