Simulation of electrophoretic stretching of DNA in a microcontraction using an obstacle array for conformational preconditioning

Recently our group has reported experiments using an obstacle array to precondition the conformations of DNA molecules to facilitate their stretch in a microcontraction. Based upon previous successes simulating electrophoretic stretching in microcontractions without obstacles, we use our simulation model to study the deformation of DNA chains in a microcontraction preceded by an array of cylindrical obstacles. We compare our data to the experimental results and find good qualitative, and even quantitative, agreement concerning the behavior of the chains in the array; however, the simulations overpredict the mean stretch of the chains as they leave the contraction. We examine the amount of stretch gained between leaving the array and reaching the end of the contraction and speculate that the differences seen are caused by nonlinear electrokinetic effects that become important in the contraction due to a combination of field gradients and high field strengths.     

Literacy in a ‘broad and balanced’ primary school curriculum: the potential of a disciplinary approach in Irish classrooms

The prominence afforded to literacy in the Irish Primary School Curriculum has received considerable attention in recent years, spurred by Programme for International Student Assessment (PISA) rankings, governmental priorities, public commentary and academic debate. At times, this discourse has presented literacy as a separate and distinct entity to the other areas of the curriculum, including the arts, social and scientific education. The current paper proposes a more integrated view of literacy’s role in the curriculum. Recent research on the teaching of literacy in the content areas has emphasised the potential of a disciplinary approach, which embraces the key skills, dispositions and forms of knowledge connected with reading, writing, speaking and listening in different disciplines. This paper examines some of the key features of disciplinary literacy, including its underpinning rationale and learning implications. It also highlights the potential for a disciplinary literacy lens in the review of the Primary School Curriculum, as well as associated opportunities and challenges.     

Preface to Special Topic: Papers from the 82nd American Chemical Society Colloid and Surface Science Symposium, Raleigh, North Carolina, 2008

This Special Topic section of Biomicrofluidics contains original contributions that were presented at the 82nd Colloid and Surface Science Symposium, which took place on 15–18 June 2008 at North Carolina State University. The Symposium covered a wide range of topics that are relevant to the fundamentals of fluidics and their application to biological systems.The recent interest in microfluidics and nanofluidics is constantly increasing due to the numerous applications that these techniques have to offer. They have been used for chemical and biomolecular sensing, separation of charged analytes, and single DNA molecule manipulation. These applications were facilitated by the significant increase in the range of advanced microfabrication and nanofabrication techniques. Improving and extending the range of applicability of micro- and nanofluidic techniques also requires better fundamental understanding of the physics of the transport at small length scales. The transport of fluids and solutes in microchannels and nanochannels usually occurs at very small Reynolds regime. The typical length scale and the surface forces (electrostatic, van der Waals, hydrophobic, hydration, etc.) may be comparable to the size of the channels. All these features often require the development of new experimental techniques and approaches for theoretical analysis.The importance and the substantial recent interest in micro- and nanofluidics prompted the organization of a special session on Electrokinetic Phenomena and Microfluidics as part of the program at the 82nd Colloid and Surface Science Symposium at North Carolina State University in June 2008. The collected papers in this issue of Biomicrofluidics cover some of the very important fundamental and engineering aspects of electrokinetic phenomena in micro- and nanofluidic channels. These include molecular dynamics simulation of biomolecules in confined spaces, analysis of the electric double layer effects on the fluid flow in nanochannels, hydrodynamic resistance to droplet motion in microchannels, electrophoresis in nanocomposite gels, and microfluidics for nanoparticle fabrication. The paper by Srivastava et al.¹ explores the possibility of using microfluidics for fabrication of Janus nanofibers. Chang² presented a theoretical analysis of the electro-osmosis on a salt-free microchannel by simultaneously solving the nonlinear Poisson–Boltzmann equation for the electrostatic potential distribution and the Navier–Stokes equations for the fluid flow. Trahan and Doyle³ reported theoretical analysis of DNA molecule interaction with obstacles in a microchannel. Finally, Labrot et al.⁴ presented studies on the droplet hydrodynamic resistance in a microfluidic channel.We hope that the reader will find the papers useful and informative.     

Test–retest reliability of the Tekscan® F-Scan® 7 in-shoe plantar pressure system during treadmill walking in healthy recreationally active individuals

In-shoe plantar pressure systems are commonly used in clinical and research settings to assess foot function during functional tasks. Recently, Tekscan® has updated their F-Scan® in-shoe plantar pressure system; however, this system’s test–retest reliability has not been established. Therefore, the purpose of this study was to determine the test–retest reliability of the F-Scan® 7 system in recreationally active individuals during treadmill walking. Seventeen healthy adults completed 2 sessions of treadmill walking. For each session, participants were fitted for shoes and pressure insoles and walked on a treadmill at a self-selected pace for 30 s. Following the sessions, the test–retest reliability peak pressure, pressure time integral, average pressure and pressure contact area over 4 regions of the foot (heel, mid-foot, forefoot and toes) was assessed by calculating intraclass coefficients (ICC 2,k) and coefficient of variation percentage (CoV%). Pressure contact area consistently had the highest ICCs and lowest CoV% (ICCs: 0.91–0.98; CoV%: 2.7–7.8%). Whereas, the forefoot and toe regions had the highest ICCs for all 4 measures (ICCs: 0.83–0.98; CoV%: 3.1–13.4%). During treadmill walking in healthy recreationally active individuals, the reliability of the new Tekscan F-Scan® ranged from poor to high and was dependent on the measure and region of the foot.     

Freedom of information in the U.K.: a progress report

Last year the author wrote about the U.K.’s plans to embrace Freedom of Information (FOI) legislation after a quarter of a century of campaigns for such legislation by the Labor Party. The Bill has now been presented to Parliament and has been amended by government to meet some objections. It is still widely criticized, however. The FOI Bill is also one of several measures that relate to openness in contemporary aspects of British government.     

Media Regulation

AMERICAN BROADCASTING AND THE FIRST AMENDMENT by Lucas A. Powe Jr. (Berkeley: University of California Press, 1987—$25)

BEYOND BROADCASTING: PATTERNS IN POLICY AND LAW by Don R. Le Due (New York: Longman, 1987—price not given)

CABLE TELEVISION AND THE FIRST AMENDMENT by Patrick Parsons (Lexington, MA: Lexington Books, 1987—$24.00)

THE QUESTION OF PORNOGRAPHY: RESEARCH FINDINGS AND POLICY IMPLICATIONS by Edward Donnerstein, et al. (New York: Free Press, 1987 $24.95)

PRIVACY IN A PUBLIC SOCIETY: HUMAN RIGHTS IN CONFLICT by Richard F. Hixson (New York: Oxford University Press, 1987—$19.95)     

Geospatial Considerations for a Multiorganizational,Landscape-Scale Program

Geospatial data play an increasingly important role in natural resources management, conservation, and science-based projects. The management and effective use of spatial data becomes significantly more complex when the efforts involve a myriad of landscape-scale projects combined with a multiorganizational collaboration. There is sparse literature to guide users on this daunting subject; therefore, we present a framework of considerations for working with geospatial data that will provide direction to data stewards, scientists, collaborators, and managers for developing geospatial management plans. The concepts we present apply to a variety of geospatial programs or projects, which we describe as a “scalable framework” of processes for integrating geospatial efforts with management, science, and conservation initiatives. Our framework includes five tenets of geospatial data management: (1) the importance of investing in data management and standardization, (2) the scalability of content/efforts addressed in geospatial management plans, (3) the lifecycle of a geospatial effort, (4) a framework for the integration of geographic information systems (GIS) in a landscape-scale conservation or management program, and (5) the major geospatial considerations prior to data acquisition. We conclude with a discussion of future considerations and challenges.