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Search Results: 1 - 10 of 38080 matches for " Bin Jiang "
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The Influence of Caldesmon Suppression on Proliferation and Motilities of Vascular Smooth Muscle Cells  [PDF]
Bin Gao, Qifeng Jiang
Journal of Biomedical Science and Engineering (JBiSE) , 2016, DOI: 10.4236/jbise.2016.99038
Abstract: Migration of vascular smooth muscle cells (VSMCs) from the media to intima constitutes a critical step in the development of proliferative vascular diseases. To elucidate the regulatory mechanism of VSMCs motility, the roles of caldesmon (CaD) were investigated previously. CaD is an actin-binding protein dynamically regulating cytoskeleton structure. In this study, the potential role of CaD in mediating proliferation and motility of VSMCs were discussed. First, structural effect of CaD on cytoskeleton integrity was analyzed with CaD knock-down; second, the proliferation of VSMCs was measured in CaD knock-down and control cells; third, the specific role of CaD on VSMCs motilities was evaluated with in vitro migration and invasion assays. We found that CaD is an integral component to maintain cytoskeleton integrity of VSMCs. Our data indicated that CaD suppression does not show significant influence on VSMCs proliferation, but negatively modulates the motilities of VSMCs, and CaD depletion would significantly facilitate migration and invasion of VSMCs.
Aquaporin 1-expressing MCF-7 mammary carcinoma cells show enhanced migration in vitro  [PDF]
Yong Jiang, Zhi-Bin Jiang
Journal of Biomedical Science and Engineering (JBiSE) , 2010, DOI: 10.4236/jbise.2010.31014
Abstract: Recent studies have demonstrated that aquaporin (AQP) expression facilitates cell migration and promotes angiogenesis and neutrophil motility. Migration of tumor cells is a crucial step in tumor invasion and metastasis. Here we investigated the expression of AQP in MCF-7 human mammary carcinoma cells and characterized its function in cell migration. Reverse Transcription–Polymerase Chain Reaction, Immunoblot and Immunofluorescence analysis demonstrated two populations of MCF-7 cell clones with low (AQP1L) and high (AQP1H) AQP1 expression and the AQP1 protein expression patterns in the plasma membrane of MCF-7 cells. MCF-7 cell clones (AQP1L and AQP1H) with low and about two-fold higher osmotic water permeability were identified by functional assays with corresponding low and high AQP1 expression. Cell migration rate was remarkably higher in AQP1H cells as compared to AQP1L cells, assessed by wound healing and transwell migration assays. Adenoviral-mediated mRNA and protein expression of AQP1 in AQP1L cells increased their water permeability and migration rate to the level similar to AQP1H cells. The results provided direct evidence that aquaporin-mediated plasma membrane water permeability played an important role in mammary carcinoma cell migration and may be associated with mammary carcinoma invasion and metastasis.
Ranking Spaces for Predicting Human Movement in an Urban Environment
Bin Jiang
Physics , 2006, DOI: 10.1080/13658810802022822
Abstract: A city can be topologically represented as a connectivity graph, consisting of nodes representing individual spaces and links if the corresponding spaces are intersected. It turns out in the space syntax literature that some defined topological metrics can capture human movement rates in individual spaces. In other words, the topological metrics are significantly correlated to human movement rates, and individual spaces can be ranked by the metrics for predicting human movement. However, this correlation has never been well justified. In this paper, we study the same issue by applying the weighted PageRank algorithm to the connectivity graph or space-space topology for ranking the individual spaces, and find surprisingly that (1) the PageRank scores are better correlated to human movement rates than the space syntax metrics, and (2) the underlying space-space topology demonstrates small world and scale free properties. The findings provide a novel justification as to why space syntax, or topological analysis in general, can be used to predict human movement. We further conjecture that this kind of analysis is no more than predicting a drunkard's walking on a small world and scale free network. Keywords: Space syntax, topological analysis of networks, small world, scale free, human movement, and PageRank
Street Hierarchies: A Minority of Streets Account for a Majority of Traffic Flow
Bin Jiang
Physics , 2008, DOI: 10.1080/13658810802004648
Abstract: Urban streets are hierarchically organized in the sense that a majority of streets are trivial, while a minority of streets is vital. This hierarchy can be simply, but elegantly, characterized by the 80/20 principle, i.e. 80 percent of streets are less connected (below the average), while 20 percent of streets are well connected (above the average); out of the 20 percent, there is 1 percent of streets that are extremely well connected. This paper, using a European city as an example, examined, at a much more detailed level, such street hierarchies from the perspective of geometric and topological properties. Based on an empirical study, we further proved a previous conjecture that a minority of streets accounts for a majority of traffic flow; more accurately, the 20 percent of top streets accommodate 80 percent of traffic flow (20/80), and the 1 percent of top streets account for more than 20 percent of traffic flow (1/20). Our study provides new evidence as to how a city is (self-)organized, contributing to the understanding of cities and their evolution using increasingly available mobility geographic information.
Editorial: Making GIScience Research More Open Access
Bin Jiang
Physics , 2013, DOI: 10.1080/13658816.2011.585613
Abstract: This is the editorial for the special issue on "data-intensive geospatial computing", which I guest edited with the International Journal of Geographical Information Science (Taylor & Francis). As remarked in the editorial, the special issue is particularly special in the sense that all source and data are published together with the published papers. This editorial elaborates on scholarly communication, with particular attention to publishing data alongside papers and the emergence of open access journals, in order to make our research more open access.
Head/tail Breaks for Visualization of City Structure and Dynamics
Bin Jiang
Physics , 2015, DOI: 10.1016/j.cities.2014.11.013
Abstract: The things surrounding us vary dramatically, which implies that there are far more small things than large ones, e.g., far more small cities than large ones in the world. This dramatic variation is often referred to as fractal or scaling. To better reveal the fractal or scaling structure, a new classification scheme, namely head/tail breaks, has been developed to recursively derive different classes or hierarchical levels. The head/tail breaks works as such: divide things into a few large ones in the head (those above the average) and many small ones (those below the average) in the tail, and recursively continue the dividing process for the large ones (or the head) until the notion of far more small things than large ones has been violated. This paper attempts to argue that head/tail breaks can be a powerful visualization tool for illustrating structure and dynamics of natural cities. Natural cities refer to naturally or objectively defined human settlements based on a meaningful cutoff averaged from a massive amount of units extracted from geographic information. To illustrate the effectiveness of head/tail breaks in visualization, I have developed several case studies applied to natural cities derived from the points of interest, social media location data, and time series nighttime images. I further elaborate on head/tail breaks related to fractals, beauty, and big data. Keywords: Big data, social media, nighttime images, natural cities, fractals, head/tail breaks, ht-index
Geospatial Analysis Requires a Different Way of Thinking: The Problem of Spatial Heterogeneity
Bin Jiang
Physics , 2014, DOI: 10.1007/s10708-014-9537-y
Abstract: Geospatial analysis is very much dominated by a Gaussian way of thinking, which assumes that things in the world can be characterized by a well-defined mean, i.e., things are more or less similar in size. However, this assumption is not always valid. In fact, many things in the world lack a well-defined mean, and therefore there are far more small things than large ones. This paper attempts to argue that geospatial analysis requires a different way of thinking - a Paretian way of thinking that underlies skewed distribution such as power laws, Pareto and lognormal distributions. I review two properties of spatial dependence and spatial heterogeneity, and point out that the notion of spatial heterogeneity in current spatial statistics is only used to characterize local variance of spatial dependence. I subsequently argue for a broad perspective on spatial heterogeneity, and suggest it be formulated as a scaling law. I further discuss the implications of Paretian thinking and the scaling law for better understanding of geographic forms and processes, in particular while facing massive amounts of social media data. In the spirit of Paretian thinking, geospatial analysis should seek to simulate geographic events and phenomena from the bottom up rather than correlations as guided by Gaussian thinking.
Wholeness as a Hierarchical Graph to Capture the Nature of Space
Bin Jiang
Physics , 2015, DOI: 10.1080/13658816.2015.1038542
Abstract: According to Christopher Alexander's theory of centers, a whole comprises numerous, recursively defined centers for things or spaces surrounding us. Wholeness is a type of global structure or life-giving order emerging from the whole as a field of the centers. The wholeness is an essential part of any complex system and exists, to some degree or other, in spaces. This paper defines wholeness as a hierarchical graph, in which individual centers are represented as the nodes and their relationships as the directed links. The hierarchical graph gets its name from the inherent scaling hierarchy revealed by the head/tail breaks, which is a classification scheme and visualization tool for data with a heavy-tailed distribution. We suggest that (1) the degrees of wholeness for individual centers should be measured by PageRank (PR) scores based on the notion that high-degree-of-life centers are those to which many high-degree-of-life centers point, and (2) that the hierarchical levels, or the ht-index of the PR scores induced by the head/tail breaks can characterize the degree of wholeness for the whole: the higher the ht-index, the more life or wholeness in the whole. Three case studies applied to the Alhambra building complex and the street networks of Manhattan and Sweden illustrate that the defined wholeness captures fairly well human intuitions on the degree of life for the geographic spaces. We further suggest that the mathematical model of wholeness be an important model of geographic representation, because it is topological oriented that enables us to see the underlying scaling structure. The model can guide geodesign, which should be considered as the wholeness-extending transformations that are essentially like the unfolding processes of seeds or embryos, for creating beautiful built and natural environments or with a high degree of wholeness.
The Flow Dimension and Capacity for Structuring Urban Street Networks
Bin Jiang
Physics , 2006, DOI: 10.1016/j.physa.2008.02.047
Abstract: This paper aims to measure the efficiency of urban street networks (a kind of complex networks) from the perspective of the multidimensional chain of connectivity (or flow). More specifically, we define two quantities: flow dimension and flow capacity, to characterize structures of urban street networks. To our surprise for the topologies of urban street networks, previously confirmed as a form of small world and scale-free networks, we find that (1) the range of their flow dimension is rather wider than their random and regular counterparts, (2) their flow dimension shows a power-law distribution, and (3) they have a higher flow capacity than their random and regular counterparts. The findings confirm that (1) both the wider range of flow dimension and the higher flow capacity can be a signature of small world networks, and (2) the flow capacity can be an alternative quantity for measuring the efficiency of networks or that of the individual nodes. The findings are illustrated using three urban street networks (two in the Europe and one in the USA).
Computing the Image of the City
Bin Jiang
Physics , 2012,
Abstract: Kevin Lynch proposed a theory of the image of the city identifying five elements that make the city legible or imageable. The resulting mental map of the city was conventionally derived through some qualitative processes, relying on interactions with city residents to ask them to recall city elements from their minds. This paper proposes a process by which the image of the city can be quantitatively derived automatically using computer technology and geospatial databases of the city. This method is substantially based on and inspired by Christopher Alexander's living structure and Nikos Salingaros' structural order, as a city with the living structure or structural order tends to be legible and imageable. With the increasing availability of geographic information of urban environments at very fine scales or resolutions (for example, trajectories data about human activities), the proposal or solution described in this paper is particularly timely and relevant for urban studies and architectural design. Keywords: Mental maps, head/tail division rule, legibility, imageability, power law, scaling, and hierarchy.
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