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521.
Ramesh Ramji Ming Wang Ali Asgar S. Bhagat Daniel Tan Shao Weng Nitish V. Thakor Chwee Teck Lim Chia-Hung Chen 《Biomicrofluidics》2014,8(3)
Droplet-based microfluidics has shown potential in high throughput single cell assays by encapsulating individual cells in water-in-oil emulsions. Ordering cells in a micro-channel is necessary to encapsulate individual cells into droplets further enhancing the assay efficiency. This is typically limited due to the difficulty of preparing high-density cell solutions and maintaining them without cell aggregation in long channels (>5 cm). In this study, we developed a short pinched flow channel (5 mm) to separate cell aggregates and to form a uniform cell distribution in a droplet-generating platform that encapsulated single cells with >55% encapsulation efficiency beating Poisson encapsulation statistics. Using this platform and commercially available Sox substrates (8-hydroxy-5-(N,N-dimethylsulfonamido)-2-methylquinoline), we have demonstrated a high throughput dynamic single cell signaling assay to measure the activity of receptor tyrosine kinases (RTKs) in lung cancer cells triggered by cell surface ligand binding. The phosphorylation of the substrates resulted in fluorescent emission, showing a sigmoidal increase over a 12 h period. The result exhibited a heterogeneous signaling rate in individual cells and showed various levels of drug resistance when treated with the tyrosine kinase inhibitor, gefitinib. 相似文献
522.
Collaborative filtering (CF) is a popular method for personalizing product recommendations for e-commerce applications. In order to recommend a product to a user and predict that user’s preference, CF utilizes product evaluation ratings of like-minded users. The process of finding like-minded users forms a social network among all users and each link between two users represents an implicit connection between them. Users having more connections with others are the most influential users. Attacking recommender systems is a new issue for these systems. Here, an attacker tries to manipulate a recommender system in order to change the recommendation output according to her wish. If an attacker succeeds, her profile is used over and over again by the recommender system, making her an influential user. In this study, we applied the established attack detection methods to the influential users, instead of the whole user set, to improve their attack detection performance. Experiments were conducted using the same settings previously used to test the established methods. The results showed that the proposed influence-based method had better detection performance and improved the stability of a recommender system for most attack scenarios. It performed considerably better than established detection methods for attacks that inserted low numbers of attack profiles (20–25 %). 相似文献
523.
This paper explores how a group of undergraduate students in the United Arab Emirates (UAE) use their mobile phones to perform
informal learning activities related to the content of their courses outside the classroom. The paper also addresses the usefulness
of informal learning activities to support students’ learning. The study adopts an exploratory case study design and uses
multiple methods of data collection including questionnaires, interviews and diary entries. Main findings suggest that students
performed informal learning activities mostly from home, interacting mainly with classmates. It also shows that students were
in control of their informal learning activities without teachers’ input. However, it was found that students used only a
limited number of applications but these were considered useful to their learning. The paper contributes to a discussion of
the implications of training and instructor support to help students to take more advantage of mobile phone applications to
support informal learning. Recommendations for further research are discussed. 相似文献
524.
While it has often been suggested that information and communication technologies (ICTs) provide an important means of increasing citizen participation (which is at the core of democratic government), few commentators have expected non-democracies to create online environments in which citizens can take an active part in political processes. In recent years, however, some non-democracies have begun to outperform countries with long-standing democratic traditions in terms of e-participation development. According to the 2010 United Nations (UN) e-government survey, Bahrain outranks France, Kazakhstan beats Sweden and Malaysia ranks higher than Germany. This article sets out to understand the recent rise of e-participation initiatives in non-democracies. Drawing on comparative longitudinal data from the UN e-government surveys, we tested the assertion that international drivers of change are competing with the dominant focus on domestic factors, especially in the non-democratic world, and are influencing the patterns of reform. The empirical analysis demonstrated important differences between the drivers of change in democratic and non-democratic countries and found economic globalization to be the strongest predictor of e-participation initiatives in non-democratic countries. In conclusion, we argue that economic globalization alters the context of e-participation and necessitates a re-examination of many of its premises and tenets. 相似文献
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Education and Information Technologies - Virtual Periodic Table (VPT) is an effective software tool to present elements in a conceivable three-dimensional (3D) mode. VPT is used to assist users in... 相似文献