Guanxi, IT Systems, and Innovation Capability: The Moderating Role of Proactiveness

In Chinese exporting, small and medium-sized companies (SMEs) need to be innovative to develop a competitive advantage. This research explored how these organizations can use two resources: 1) guanxi with customers, distributors, suppliers, and government officials; and 2) IT systems to enhance their innovation capabilities and new product performance. The moderating role of an organization’s proactiveness with respect to new product development is also examined. The resource-based view provides the theoretical support for the research. A conceptual model is developed and tested using survey data gathered from 210 Chinese SMEs in manufacturing industries that were analyzed using SmartPLS 2.0. Results show that IT systems are positively related to innovation capability. The relationship between guanxi and innovation capability is significant for firms that exhibit high levels of proactiveness but not when proactiveness is low

Compressive stress enhances coordinated migration of mammary carcinoma cells

Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2010.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student submitted PDF version of thesis.Includes bibliographical references.Cancer research has traditionally focused on genetic and biochemical changes during tumor progression. Uncontrolled cell proliferation of a solid tumor in a confined space not only creates well-studied oxidative stress (hypoxia), but also generates growth-induced mechanical stress (compression). However, the importance of such compressive stress in tumor biology has been largely ignored. Our lab has previously shown that compressive stress influences tumor spheroid growth and stimulates production of extracellular matrix molecules. Others have also demonstrated the importance of matrix rigidity in tumor development and enhanced tumor cell adhesion by hydrostatic pressure. Yet whether growth-induced compressive stress can enhance caner cell migration and invasion remains unclear. The focus of this thesis is to evaluate the effect of anisotropic compressive stress on cancer cell motility. To mimic growth-induced compressive stress experienced by cancer cells in vivo, we developed an in vitro compression device for compressing a monolayer of cancer cells with precisely-defined normal forces. Here we show, for the first time, that externally-applied compressive stress resulted in faster migration of some mammary carcinoma cell lines. Independent of multi-cellular micro-organization, compression induced migration of mammary carcinoma cells in a coordinated sheet, initiated by "leader cells" -- single cells at the leading edge of the sheet, extending long filopodia.(cont.) Accompanied by redistribution of fibronectin deposition, compression enhanced cell-matrix adhesion and stabilized cell distension, thereby promoting coordinated cell migration. Using a stochastic model to simulate 2-D collective cell migration, cell distension and uniform cell migration were found to be crucial factors for effective collective migration. Our finding on compression-induced coordinated migration of mammary carcinoma cells has significant implications for in vivo situations where epithelial cancer cells form a "coordinated" invading mass guided by "leader" cells. Our work suggests that compressive stress generated by proliferating cancer cells can distort their shape, enhance cell-substrate adhesion and stimulate formation of leader cells responsible for collective cell migration. This discovery could open the door to characterization of novel pathways driven by mechanical-stress and improved strategies for cancer treatment.by Janet M. Tse.Sc.D

Reliable and valid NEWS for Chinese seniors: measuring perceived neighborhood attributes related to walking

Background : The effects of the built environment on walking in seniors have not been studied in an Asian context. To examine these effects, valid and reliable measures are needed. The aim of this study was to develop and validate a questionnaire of perceived neighborhood characteristics related to walking appropriate for Chinese seniors (Neighborhood Environment Walkability Scale for Chinese Seniors, NEWS-CS). It was based on the Neighborhood Environment Walkability Scale - Abbreviated (NEWS-A), a validated measure of perceived built environment developed in the USA for adults. A secondary study aim was to establish the generalizability of the NEWS-A to an Asian high-density urban context and a different age group. Methods : A multidisciplinary panel of experts adapted the original NEWS-A to reflect the built environment of Hong Kong and needs of seniors. The translated instrument was pre-tested on a sample of 50 Chinese-speaking senior residents (65+ years). The final version of the NEWS-CS was interviewer-administered to 484 seniors residing in four selected Hong Kong districts varying in walkability and socio-economic status. Ninety-two participants completed the questionnaire on two separate occasions, 2-3 weeks apart. Test-rest reliability indices were estimated for each item and subscale of the NEWS-CS. Confirmatory factor analysis was used to develop the measurement model of the NEWS-CS and cross-validate that of the NEWS-A. Results : The final version of the NEWS-CS consisted of 14 subscales and four single items (76 items). Test-retest reliability was moderate to good (ICC > 50 or % agreement > 60) except for four items measuring distance to destinations. The originally-proposed measurement models of the NEWS-A and NEWS-CS required 2-3 theoretically-justifiable modifications to fit the data well. Conclusions : The NEWS-CS possesses sufficient levels of reliability and factorial validity to be used for measuring perceived neighborhood environment in Chinese seniors. Further work is needed to assess its construct validity and generalizability to other Asian locations. In general, the measurement model of the original NEWS-A was generalizable to this study context, supporting the feasibility of cross-country and age-group comparisons of the effect of the neighborhood environment on walking using the NEWS-A as a tool to measure the perceived built environment

Detection and Monitoring of Marine Pollution Using Remote Sensing Technologies

Recently, the marine habitat has been under pollution threat, which impacts many human activities as well as human life. Increasing concerns about pollution levels in the oceans and coastal regions have led to multiple approaches for measuring and mitigating marine pollution, in order to achieve sustainable marine water quality. Satellite remote sensing, covering large and remote areas, is considered useful for detecting and monitoring marine pollution. Recent developments in sensor technologies have transformed remote sensing into an effective means of monitoring marine areas. Different remote sensing platforms and sensors have their own capabilities for mapping and monitoring water pollution of different types, characteristics, and concentrations. This chapter will discuss and elaborate the merits and limitations of these remote sensing techniques for mapping oil pollutants, suspended solid concentrations, algal blooms, and floating plastic waste in marine waters