Molecular diffusion analysis of dynamic blood flow and plasma separation driven by self-powered microfluidic devices

Integration of microfluidic devices with pressure-driven, self-powered fluid flow propulsion methods has provided a very effective solution for on-chip, droplet blood testing applications. However, precise understanding of the physical process governing fluid dynamics in polydimethylsiloxane (PDMS)-based microfluidic devices remains unclear. Here, we propose a pressure-driven diffusion model using Fick''s law and the ideal gas law, the results of which agree well with the experimental fluid dynamics observed in our vacuum pocket-assisted, self-powered microfluidic devices. Notably, this model enables us to precisely tune the flow rate by adjusting two geometrical parameters of the vacuum pocket. By linking the self-powered fluid flow propulsion method to the sedimentation, we also show that direct plasma separation from a drop of whole blood can be achieved using only a simple construction without the need for external power sources, connectors, or a complex operational procedure. Finally, the potential of the vacuum pocket, along with a removable vacuum battery to be integrated with non-PDMS microfluidic devices to drive and control the fluid flow, is demonstrated.     

Validation of a videogrammetry technique for analysing American football helmet kinematics

ABSTRACT

Professional American football games are recorded in digital video with multiple cameras, often at high resolution and high frame rates. The purpose of this study was to evaluate the accuracy of a videogrammetry technique to calculate translational and rotational helmet velocity before, during and after a helmet impact. In total, 10 football impacts were staged in a National Football League (NFL) stadium by propelling helmeted 50th percentile male crash test dummies into each other or the ground at speeds and orientations representative of concussive impacts for NFL players. The tests were recorded by experienced sports film crews to obtain video coverage and quality typically available for NFL games. A videogrammetry procedure was used to track the position and rotation of the helmet throughout the relevant time interval of the head impact. Compared with rigidly mounted retroreflective marker three dimensional (3-D) motion tracking that was concurrently collected in the experiments, videogrammetry accurately calculated changes in translational and rotational velocity of the helmet using high frame rate (two cameras at 240 Hz) video (7% and 15% error, respectively). Low frame rate (2 cameras at 60 Hz) video was adequate for calculating pre-impact translational velocity but not for calculating the translational or rotational velocity change of the helmet during impact.     

The long tail: a usage analysis of pre-1993 print biomedical journal literature

Objective: The research analyzes usage of a major biomedical library''s pre-1993 print journal collection.Methodology: In July 2003, in preparation for a renovation and expansion project, the Biomedical Library at the University of California, San Diego, moved all of its pre-1993 journal volumes off-site, with the exception of twenty-two heavily used titles. Patrons wishing to consult one of these stored volumes could request that it be delivered to the library for their use. In the spring of 2006, an analysis was made of these requests.Results: By July of 2006, 79,827 journal volumes published in 1992 or earlier had been requested from storage. The number of requests received declined with age of publication. The usage distribution exhibited a “long tail”: 50% of the 79,827 requests were for journal volumes published before 1986. The availability of electronic access dramatically reduced the chance that corresponding print journal volumes would be requested.Conclusions: The older biomedical print journal literature appears to be of continued value to the biomedical research community. When electronic access was provided to the older literature, demand for older print volumes declined dramatically.

Highlights

• Analysis of requests for stored biomedical journal volumes published prior to 1993 indicates that older biomedical journal literature receives substantial use: during this 3-year study, there were nearly 80,000 requests for journal volumes published in 1992 or earlier, with half the requests for volumes published from 1986–1992 and 40% of the request for volumes published from 1970–1985. These results indicate that retaining older print volumes, or providing easy access to the older literature through electronic journals or other means, will likely be required to meet user information needs.
• Use of older journal volumes varies by title and by user population, and a small number of journal titles were responsible for most of the use.
• Requests for older print biomedical journal titles dropped significantly when electronic access became available.

Implications

• Biomedical libraries should carefully consider implications of eliminating on-site access to older journal literature for users and budgets.
• Removing access to older journal literature may result in higher demand for interlibrary loan and document delivery services.
• Biomedical libraries can safely substitute reliable electronic access to older literature to meet ongoing needs for this information, thereby creating space for other purposes.

     

Construct Validity of Adults’ Retrospective Memory for Childhood TV Viewing: Self-Reported Early Exposure to Violent TV Programs Predicts Current Aggression

Construct validity was investigated of a measure of remote past television viewing in which adults reported their childhood viewing of specific television series. Good recall of past viewing was predicted due to two robust memory capabilities, specifically, high accuracy at estimating frequency of exposure to stimuli, and durable long-term memories for repeatedly-encountered material. Validity was tested by examining relationships between self-reported childhood TV viewing and current aggression. Results indicated that recalled childhood viewing of programs containing violent content was positively related to adult aggressive behavior directly, and aggressive cognitions indirectly, independently of adult exposure to violent TV programs, exposure to nonviolent TV programs, parental disciplinary style, and sex. A valid self-report measure of remote past TV viewing behavior can enable researchers to examine, in a relatively quick and inexpensive manner, long-term relationships between early viewing of any television content and any later psychological outcomes of interest.     

Failure Modes and Effects Analysis (FMEA) for Cataloging: An Application and Evaluation

Failure Modes and Effects Analysis (FMEA) is a proactive assessment tool originally created for quality assurance in manufacturing industries. FMEA involves the assignment of rankings for frequency, severity, and detection of errors within a process. Catalogers at ProQuest undertook an innovative project to use FMEA to evaluate MARC record production. This article provides an overview of FMEA for process evaluation and summarizes an application for cataloging. It considers the tool's value for error-proofing in MARC record creation and how FMEA might be applied more effectively in a variable environment.     

Team-Based Ultrasound Objective Structured Practice Examination (OSPE) in the Anatomy Course

The clinical use of ultrasound has dramatically increased, necessitating early ultrasound education and the development of new tools in ultrasound training and assessment. The goal of this study was to devise a novel low-resource examination that tested the anatomical knowledge and technical skill of early undergraduate medical students in a gross anatomy course. The team-based ultrasound objective structured practice examination (OSPE) was created as a method for assessing practical ultrasound competencies, anatomical knowledge, and non-technical skills such as teamwork and professionalism. The examination utilized a rotation of students through four team roles as they scanned different areas of the body. This station-based examination required four models and four instructors, and tested ultrasound skills in the heart, abdominal vessels, abdominal organs, and neck regions. A Likert scale survey assessed student attitudes toward the examination. Survey data from participants (n = 46) were examined along with OSPE examination grades (n = 52). Mean and standard deviations were calculated for examination items and survey responses. Student grades were high in both technical (96.5%). and professional (96.5%) competencies with structure identification scoring the lowest (93.8%). There were no statistical differences between performances in each of the body regions being scanned. The survey showed that students deemed the examination to be fair and effective. In addition, students agreed that the examination motivated them to practice ultrasound. The team-based OSPE was found to be an efficient and student-favored method for evaluating integrated ultrasound competencies, anatomical knowledge, team-work, and professional attributes.     

Faculty/Staff Perceptions of a Standards-Based Exit Portfolio System for Graduate Students

New standards for certification were recently developed for speech–language pathology graduate training programs by the American Speech-Language-Hearing Association. The new standards are outcomes-based rather than process-based. Using a collective case study approach, this article highlights the perceptions of faculty and staff regarding use of a standards-based exit portfolio system for students in a Speech–Language Pathology graduate program at a medium-sized, public university after two semesters of use.Tena L. McNamara received a B.S. degree in Speech Pathology and Audiology and an M.S. degree in Audiology from Bradley University, and the Doctor of Audiology Degree from the University of Florida. She is now Assistant Professor at Illinois State University. Special interests include soundfield FM systems utilized in classroom settings, auditory processing disorders, electrophysiology, and phonological awareness. Rita L. Bailey is a speech–language pathologist and holds a B.S. and an M.S. in Speech–Language Pathology and an Ed.D. in Special Education, all from Illinois State University. She is an Assistant Professor in the Department of Speech Pathology and Audiology at Illinois State University. Her primary research interests include pediatric dysphagia, service-learning, alternative-augmentative communication methods, and voice. E-mail: tlmcnam@ilstu.edu.     

学校与工作的整合——教育及变革中的工作场所

本文通过对相对工资变化和职业分布数据的分析及案例的研究,认为主导美国的传统教育观念未能有效地为今日市场准备好各种人力资源;而新近对高绩效工作模式和教与学的研究显示,一种将学术教育与职业教育整合的改革,对增强劳动队伍的有效性,提高其“高级的通用能力”起重要作用。其中工作场所和课程的整合不能各自孤立地进行,需纳入重新构建学校和工作场所双方更宽泛的战略之中。