An integrated approach to untangling mediated connectedness with online and mobile media

With the growth and convergence of mobile and social computing technology, mobile media are accorded new social meaning manifested in different aspects of our everyday life. This paper employs multiple theoretical frameworks—including the theory of the niche, the framework of media repertoires, and the communication infrastructure model—to examine individual-technology relationship as manifested through media repertoires and media connectedness. It argues that individuals tend to construct a set of media options and build connectedness with media technologies by engaging in a wide scope of activities through these media. In turn, this media repertoire and media connectedness may facilitate the performance of social and cultural practices in the public space. To investigate this conceptualization empirically, this study conducted a secondary analysis of data collected by the Pew Research Center in the United States. The results showed that multidimensional use of mobile apps was predicted by multidimensional Internet use, along with the scope of regular apps used and monetary investment by users. Additionally, multidimensional Internet use and the use of media repertoires consisting of mobile media and social media for socio-cultural activities facilitate public socio-cultural engagement. These results bring to light a new way of understanding how humans appropriate multiple types of technologies for activities in everyday life.     

Applications of scaffolds: Tools for enhancing the immunomodulation of mesenchymal stromal cells

Exogenously delivered mesenchymal stromal cells (MSCs) are therapeutically beneficial owing to their paracrine effect; they secrete various cytokines, nucleic acids, and proteins. Multiple bioengineering techniques can help MSC cultures to release secretomes by providing stem cell niche-like conditions (both structurally and functionally). Various scaffolds mimic the natural extracellular matrix (ECM) using both natural and synthetic polymers, providing favorable environments for MSC proliferation and differentiation. Depending on material properties, either topographically or elastically structured scaffolds can be fabricated. Three-dimensional scaffolds have tunable substrate rigidities and structures, aiding MSC cultivation. Decellularized ECM-derived hydrogels are similar to the natural ECM, thus improving the paracrine effects of MSCs. Here, we discuss recent research on the application of scaffolds to maximize the immunomodulatory function of MSCs.     

Emergence and the Forms of Metabolism

Earlier this year, Michael Weinstock published a seminal book, The Architecture of Emergence: The Evolution of Form in Nature and Civilisation, which challenges established cultural and architectural histories. The conventional worldview is expanded by placing human development alongside ecological development: the history of cultural evolution and the production of cities are set in the context of processes and forms of the natural world. As well as providing a far-reaching thesis, Weinstock's book gives lucid and accessible explanations of the complex systems of the physical world. In this abridged extract from Chapter 5, Weinstock explains the dynamics of individual and collective metabolisms from which intelligence and social and spatial orders emerge. Copyright © 2010 John Wiley & Sons, Ltd.     

基于遗传算法的火炮总体参数动力学优化

为提高火炮射击精度,寻找最佳的总体参数,本文利用小生境遗传算法,实现了与ADAMS软件联合进行火炮总体参数动力学优化设计。结合某火炮,对上述方法进行了计算,计算结果表明：优化后的炮口扰动值比优化前明显降低;小生境遗传算法一次可以搜索出多个有效方案,给火炮总体布置带来更大灵活性。     

小生境遗传算法在孔隙介质反演中的应用研究

为加快寻找地下复杂介质中的油气，针对含单相饱和流体的孔隙介质，综合了等效孔隙介质理论、Radon变换以及小生境遗传算法等，将接收信号与遗传群体相联系，引入了最小二乘原理和小生境迭代，形成了基于等效孔隙介质模型与地震CT技术的小生境多参数反演算法。理论分析与反演结果表明，该方法能够有效避开波动方程求解的复杂性，精度高、求解方便，具有一定的实用价值，能有效解决井间地层成像问题。图2表2参16     

Strategic niche management for biofuels: Analysing past experiments for developing new biofuel policies

Biofuels have gained a lot of attention since the implementation of the 2003 European Directive on biofuels. In the Netherlands the contribution of biofuels is still very limited despite several experiments in the past. This article aims to contribute to the development of successful policies for stimulating biofuels by analysing three experiments in depth. The approach of strategic niche management (SNM) is used to explain success and failure of these projects. Based on the analysis as well as recent innovation literature we develop a list of guidelines that is important to consider when developing biofuel policies.     

Optimization of Rolling Force Distribution Based on Niche Genetic Algorithm in Continuous Hot Rolling Mills

Based on the niche genetic algorithm, the intelligent and optimizing model for the rolling force distribution in hot strip mills was put forward. The research showed that the model had many advantages such as fast searching speed, high calculating pre- cision and suiting for on-line calculation. A good strip shape could be achieved by using the model and it is appropriate and practica-ble for rolling producing.     

Injectable and Crosslinkable PLGA‐Based Microribbons as 3D Macroporous Stem Cell Niche

Poly(lactide‐co‐glycolide) (PLGA) has been widely used as a tissue engineering scaffold. However, conventional PLGA scaffolds are not injectable, and do not support direct cell encapsulation, leading to poor cell distribution in 3D. Here, a method for fabricating injectable and intercrosslinkable PLGA microribbon‐based macroporous scaffolds as 3D stem cell niche is reported. PLGA is first fabricated into microribbon‐shape building blocks with tunable width using microcontact printing, then coated with fibrinogen to enhance solubility and injectability using aqueous solution. Upon mixing with thrombin, firbornogen‐coated PLGA microribbons can intercrosslink into 3D scaffolds. When subject to cyclic compression, PLGA microribbon scaffolds exhibit great shock‐absorbing capacity and return to their original shape, while conventional PLGA scaffolds exhibit permanent deformation after one cycle. Using human mesenchymal stem cells (hMSCs) as a model cell type, it is demonstrated that PLGA μRB scaffolds support homogeneous cell encapsulation, and robust cell spreading and proliferation in 3D. After 28 days of culture in osteogenic medium, hMSC‐seeded PLGA μRB scaffolds exhibit an increase in compressive modulus and robust bone formation as shown by staining of alkaline phosphatase, mineralization, and collagen. Together, the results validate PLGA μRBs as a promising injectable, macroporous, non‐hydrogel‐based scaffold for cell delivery and tissue regeneration applications.     

Deconstructed Microfluidic Bone Marrow On‐A‐Chip to Study Normal and Malignant Hemopoietic Cell–Niche Interactions

Human hematopoietic niches are complex specialized microenvironments that maintain and regulate hematopoietic stem and progenitor cells (HSPC). Thus far, most of the studies performed investigating alterations of HSPC‐niche dynamic interactions are conducted in animal models. Herein, organ microengineering with microfluidics is combined to develop a human bone marrow (BM)‐on‐a‐chip with an integrated recirculating perfusion system that consolidates a variety of important parameters such as 3D architecture, cell–cell/cell–matrix interactions, and circulation, allowing a better mimicry of in vivo conditions. The complex BM environment is deconvoluted to 4 major distinct, but integrated, tissue‐engineered 3D niche constructs housed within a single, closed, recirculating microfluidic device system, and equipped with cell tracking technology. It is shown that this technology successfully enables the identification and quantification of preferential interactions—homing and retention—of circulating normal and malignant HSPC with distinct niches.     

使用特征点与灰度值的医学图像局部配准方法

针对医学图像配准中,存在某些图像间大部分区域没有差异或者存在差异但不被关心的情况,提出了一种局部图像配准方法。该方法使用局部可控的紧支撑径向基函数作为配准变换函数,通过在感兴趣区域设置特征点,将变换函数作用范围限制在图像中某一特定区域,保持其他区域不发生变形。利用图像间的互信息量作为测度函数,更加精确地求解变换函数。在优化策略的选择中,将图像配准看作为寻优过程,采用基于小生境的遗传算法优化变换函数参数,能够克服经典遗传算法早熟、搜索能力差等缺点。通过对已知变换函数的仿真图像与真实医学图像进行实验,结果表明该算法能够准确地找到较优的变换函数,并且将作用区域限制在较小范围内。该方法结合了基于特征点和基于像素配准方法的优点,有效的搜索策略保证了变换函数准确性,是一种可行的、鲁棒的局部医学图像配准方法。