Centrifugal multiplexing fixed-volume dispenser on a plastic lab-on-a-disk for parallel biochemical single-end-point assays

In this study, a multiple sample dispenser for precisely metered fixed volumes was successfully designed, fabricated, and fully characterized on a plastic centrifugal lab-on-a-disk (LOD) for parallel biochemical single-end-point assays. The dispenser, namely, a centrifugal multiplexing fixed-volume dispenser (C-MUFID) was designed with microfluidic structures based on the theoretical modeling about a centrifugal circumferential filling flow. The designed LODs were fabricated with a polystyrene substrate through micromachining and they were thermally bonded with a flat substrate. Furthermore, six parallel metering and dispensing assays were conducted at the same fixed-volume (1.27 μl) with a relative variation of ±0.02 μl. Moreover, the samples were metered and dispensed at different sub-volumes. To visualize the metering and dispensing performances, the C-MUFID was integrated with a serpentine micromixer during parallel centrifugal mixing tests. Parallel biochemical single-end-point assays were successfully conducted on the developed LOD using a standard serum with albumin, glucose, and total protein reagents. The developed LOD could be widely applied to various biochemical single-end-point assays which require different volume ratios of the sample and reagent by controlling the design of the C-MUFID. The proposed LOD is feasible for point-of-care diagnostics because of its mass-producible structures, reliable metering/dispensing performance, and parallel biochemical single-end-point assays, which can identify numerous biochemical.     

Exploring the International Student Experience: Providing Insight Through a Mixed-Methods Approach

Southern Illinois University Edwardsville (SIUE) has seen a dramatic increase in international student enrollment in the last four years. To serve this rising population effectively, librarians at SIUE created a research study to explore the information needs and academic experiences of international students at SIUE. The study employed a mixed-methods approach including a survey as well as in-depth interviews and photo diaries. The results provide insight into international students’ library use and academic life.     

Learning Politics From Social Media: Interconnection of Social Media Use for Political News and Political Issue and Process Knowledge

Drawing on a national survey of 1,157 South Korean adults, the present study finds that social media use for political news is positively associated with knowledge about political issues, but not with knowledge about political processes. Professional media use for political news is significantly associated with both political issue knowledge and political process knowledge. The impact of social media for news on political issue knowledge increases with the additive role of professional media news use. This study also finds that political talk strengthens the positive association between social media use for news and political issue knowledge.     

Synchronization of discrete-time complex dynamical networks with interval time-varying delays via non-fragile controller with randomly occurring perturbation

This paper addresses synchronization problem for discrete-time complex dynamical networks with interval time-varying delays. In order to achieve the synchronization, a feedback controller subjected to randomly occurring perturbations will be considered. The randomly occurring perturbations are assumed to belong to the Binomial sequence. By constructing a suitable Lyapunov–Krasovskii functional, and utilizing reciprocally convex approach and Finsler?s lemma, the synchronization criteria for the networks are established in terms of linear matrix inequalities (LMIs) which can be easily solved by various effective optimization algorithms. The networks are represented by the use of Kronecker product technique. The effectiveness of the proposed methods will be verified via numerical examples.     

Programmed sample delivery on a pressurized paper

This paper reports a method to control the fluid flow in paper-based microfluidic devices simply by pressing over the channel surface of paper, thereby decreasing the pore size and permeability of a non-woven polypropylene sheet. As a result, fluid resistance is increased in the pressed region and causes flow rate to decrease. We characterize the decrease of flow rate with respect to different amounts of pressure applied, and up to 740% decrease in flow velocity was achieved. In addition, we demonstrate flow rate control in a Y-shaped merging paper and sequential delivery of multiple color dyes in a three-branched paper. Furthermore, sequential delivery of multiple fluid samples is performed to demonstrate its application in multi-step colorimetric immunoassay, which shows a 4.3-fold signal increase via enhancement step.     

Stabilizability of complex complex-valued memristive neural networks using non-fragile sampled-data control

This paper investigates the stability and stabilizability of complex-valued memristive neural networks (CVMNNs) with random time-varying delays via non-fragile sampled-data control. Taking the influence of gain fluctuations into account, a non-fragile sampled-data controller is designed for CVMNNs. Compared with the existing control schemes, the one here is more applicable and can effectively save the communication resources. The assumption on activation functions of CVMNNs is relaxed by only needing the complex-valued activation functions satisfying the Lipschitz condition. By constructing a suitable Lyapunov–Krasovskii functional (LKF), new stability and stabilizability criteria are derived for CVMNNs. Different from the existing results with the maximum absolute values of memristive connection weights, our ones are based on the average values of the maximum and minimum of the memristive connection weights. Finally, numerical simulations are given to validate the effectiveness of the theoretical results.     

How do congressional members appear on the web? Tracking the web visibility of South Korean politicians

The web visibility of politicians has substantial implications for the internet and politics. In this regard, the present paper examines the web visibility of South Korea's 18th National Assembly members. This study identifies those members with the highest web visibility and determines the factors affecting their web visibility by using a set of socio-demographic variables indicating web visibility. The concept of web visibility is operationally defined as the number of web mentions of each congressional member. Web mentions of the name of each congressional member were collected across many platforms, including blogs, images, news, and websites, by using a Naver search tool based on the API, and relationships between the web visibility of the members and their socio-demographic attributes (their gender, age, term, constituency, and party affiliation) were analyzed using Kruskal–Wallis, Median, and Mann–Whitney U tests. The most visible politicians in the Korean webosphere had highly qualified political careers and prominence, and the difference in politicians' web visibility depended on their political attributes (their term, constituency, and party), not on their demographic attributes (their gender and age). These findings suggest that politicians who build political power and influence through their political career in the offline world are likely to be more visible in the webosphere. Further, an integrated indicator based on politicians' web visibility status can reflect their “ubiquitous presence” in Korea's digitalized society.