Science signaling podcast: 21 July 2015

© 2015 American Association for the Advancement of Science. All rights Reserved. This Podcast features an interview with Cristina Murga and Rocio Vila-Bedmar, authors of a Research Article that appears in the 21 July 2015 issue of Science Signaling, about how deleting the kinase GRK2 can counteract some of the metabolic effects of a bad diet. Obesity affects many of the body's normal functions, most notably metabolism. Obesity is associated with insulin resistance and reduced glucose tolerance, which can lead to type 2 diabetes. It also promotes hepatic steatosis, the accumulation of fat in the liver. Vila-Bedmar et al. show that deleting GRK2 can prevent further weight gain and hepatic steatosis and improve glucose sensitivity in obese mice. Deleting GRK2 improved these metabolic consequences of high-fat diet-induced obesity even if the kinase was deleted after the mice had already become obese and resistant to insulin.Peer Reviewe

Specific modulation of airway epithelial tight junctions by apical application of an occludin peptide

Tight junctions are directly involved in regulating the passage of ions and macromolecules (gate functions) in epithelial and endothelial cells. The modulation of these gate functions to transiently regulate the paracellular permeability of large solutes and ions could increase the delivery of pharmacological agents or gene transfer vectors. To reduce the inflammatory responses caused by tight junction-regulating agents, alternative strategies directly targeting specific tight junction proteins could prove to be less toxic to airway epithelia. The apical delivery of peptides corresponding to the first extracellular loop of occludin to transiently modulate apical paracellular flux has been demonstrated in intestinal epithelia. We hypothesized that apical application of these occludin peptides could similarly modulate tight junction permeability in airway epithelia. Thus, we investigated the effects of apically applied occludin peptide on the paracellular permeability of molecular tracers and viral vectors in well differentiated human airway epithelial cells. The effects of occludin peptide on cellular toxicity, tight junction protein expression and localization, and membrane integrity were also assessed. Our data showed that apically applied occludin peptide significantly reduced transepithelial resistance in airway epithelia and altered tight junction permeability in a concentration-dependent manner. These alterations enhanced the paracellular flux of dextrans as well as gene transfer vectors. The occludin peptide redistributed occludin but did not alter the expression or distribution of ZO-1, claudin-1, or claudin-4. These data suggest that specific targeting of occludin could be a better-suited alternative strategy for tight junction modulation in airway epithelial cells compared with current agents that modulate tight junctions

Planform selection in two-layer Benard-Marangoni convection

Benard-Marangoni convection in a system of two superimposed liquids is investigated theoretically. Extending previous studies the complete hydrodynamics of both layers is treated and buoyancy is consistently taken into account. The planform selection problem between rolls, squares and hexagons is investigated by explicitly calculating the coefficients of an appropriate amplitude equation from the parameters of the fluids. The results are compared with recent experiments on two-layer systems in which squares at onset have been reported.Comment: 17 pages, 7 figures, oscillatory instability included, typos corrected, references adde

Uncovering identities through performance poetry

Research in the area of performance poetry is still relatively new to the field of communication. Using Hecht’s Communication Theory of Identity, this study explores performance poetry as a communicative tool for identity management. By observing the performances of five poets from six seasons of HBO’s Def Poetry Jam, a thematic analysis of the communication practices that occurred during the performances was used to code the processes of identity management. Additionally, this study explores how validation of enacted identity occurs between the poets and their audiences. Findings suggest that performance poetry could effectively be utilized as a tool in identity management that would offer both a macro and a micro evaluation of multiple identities on multiple levels; and validation occurred as either a natural or prompted response. Overall, this study demonstrates the usefulness of performance poetry in not only self-expression by also as valuable instrument in managing identity

Onset of Surface-Tension-Driven Benard Convection

Experiments with shadowgraph visualization reveal a subcritical transition to a hexagonal convection pattern in thin liquid layers that have a free upper surface and are heated from below. The measured critical Marangoni number (84) and observation of hysteresis (3%) agree with theory. In some experiments, imperfect bifurcation is observed and is attributed to deterministic forcing caused in part by the lateral boundaries in the experiment.Comment: 4 pages. The RevTeX file has a macro allowing various styles. The appropriate style is "mypprint" which is the defaul

Pearling and Pinching: Propagation of Rayleigh Instabilities

A new category of front propagation problems is proposed in which a spreading instability evolves through a singular configuration before saturating. We examine the nature of this front for the viscous Rayleigh instability of a column of one fluid immersed in another, using the marginal stability criterion to estimate the front velocity, front width, and the selected wavelength in terms of the surface tension and viscosity contrast. Experiments are suggested on systems that may display this phenomenon, including droplets elongated in extensional flows, capillary bridges, liquid crystal tethers, and viscoelastic fluids. The related problem of propagation in Rayleigh-like systems that do not fission is also considered.Comment: Revtex, 7 pages, 4 ps figs, PR

Low-Prandtl-number B\'enard-Marangoni convection in a vertical magnetic field

The effect of a homogeneous magnetic field on surface-tension-driven B\'{e}nard convection is studied by means of direct numerical simulations. The flow is computed in a rectangular domain with periodic horizontal boundary conditions and the free-slip condition on the bottom wall using a pseudospectral Fourier-Chebyshev discretization. Deformations of the free surface are neglected. Two- and three-dimensional flows are computed for either vanishing or small Prandtl number, which are typical of liquid metals. The main focus of the paper is on a qualitative comparison of the flow states with the non-magnetic case, and on the effects associated with the possible near-cancellation of the nonlinear and pressure terms in the momentum equations for two-dimensional rolls. In the three-dimensional case, the transition from a stationary hexagonal pattern at the onset of convection to three-dimensional time-dependent convection is explored by a series of simulations at zero Prandtl number.Comment: 26 pages, 9 figure

A Case Study of the Southwest Virginia Higher Education Center

The purpose of the study was to identify the impact that the Southwest Virginia Higher Education Center (SWVHEC), located in Abingdon, has had on area residents in the past twenty years. The case study presented here is different from others that have been written in that it measures the number of courses offered, student registrations, and professional developments available to local residents. The data was collected and triangulated using different methods, such as structured interviews, archival records, newspaper articles, University websites, and participant-observations. The study included colleges and universities with either main campuses or satellite locations in Southwest Virginia and Northeast Tennessee, specifically Bluefield College, East Tennessee State University, Emory & Henry College, King University, Old Dominion University, Radford University, University of Virginia, University of Virginia’s College at Wise, Virginia Commonwealth University, Virginia Highlands Community College, and Virginia Polytechnic Institute and State University. (SWVHEC, 2017) The former participating colleges are George Mason University, Norfolk State, and Virginia Intermont College. The outcomes of the study identified almost 40,000 registrations from all of the colleges combined from area residents over the past twenty years. The average number of individuals served per year is 1,024. During the year 2000 the SWVHEC served the largest number of individuals (1,568), while during the year 2015 experienced the lowest number of individuals served (286). Currently, the trends in enrollments from most of the partner colleges show a decline. Declining student enrollment is a major cause of concern for the colleges, and by extension the Center. To address this problem, the Executive Director who took control in 2015, David Matlock, has revitalized the partnership with King University and its Nursing Program. Mr. Matlock also secured a grant for Mt. Rogers Regional Adult Education (MRRAE) Program to offer General Educational Development (GED) and English as a Second Language (ESL) classes in the Center. Also, MRRAE recently signed a contract to lease an office, two classrooms and a computer lab. Another new collaboration Mr. Matlock established is with Goodwill Education Center. These and other new partnerships and programs are beginning to fill the empty classrooms and offices in the SWVHEC. Opportunities for growth are a high priority for the Center and its staff

Cocoa and Chocolate: Deconstructing the Development Paradigm in Cameroon

This project focuses specifically on the neo-liberal economic iteration of international development. Neo-liberalism is the idea that the deregulation of the private sector and expansion of free trade will lead to growth in undeveloped countries, which will effectively end poverty and increase the standard of living. My ethnography in Southwest Cameroon, however, shows that the experience and embodiment of development takes on a new understanding at the local, daily level. Exploring the paradox of cocoa and chocolate in Cameroon, I find that while the average Cameroonian is able to grow cocoa, he/she is unable to afford chocolate. This context calls for a critiquing of the assumptions which undergird the development paradigm in order to understand how and why it so often fails, as well to reconcile development with the local understandings and needs in the Global South, generally, and Southwest Cameroon, specifically