Drexel University

About: Drexel University is a education organization based out in Philadelphia, Pennsylvania, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 26770 authors who have published 51438 publications receiving 1949443 citations. The organization is also known as: Drexel & Drexel Institute.

Regulation of Growth Cone Actin Filaments by Guidance Cues

Abstract: The motile behaviors of growth cones at the ends of elongating axons determine pathways of axonal connections in developing nervous systems. Growth cones express receptors for molecular guidance cues in the local environment, and receptor-guidance cue binding initiates cytoplasmic signaling that regulates the cytoskeleton to control growth cone advance, turning, and branching behaviors. The dynamic actin filaments of growth cones are frequently targets of this regulatory signaling. Rho GTPases are key mediators of signaling by guidance cues, although much remains to be learned about how growth cone responses are orchestrated by Rho GTPase signaling to change the dynamics of polymerization, transport, and disassembly of actin filaments. Binding of neurotrophins to Trk and p75 receptors on growth cones triggers changes in actin filament dynamics to regulate several aspects of growth cone behaviors. Activation of Trk receptors mediates local accumulation of actin filaments, while neurotrophin binding to p75 triggers local decrease in RhoA signaling that promotes lengthening of filopodia. Semaphorin IIIA and ephrin-A2 are guidance cues that trigger avoidance or repulsion of certain growth cones, and in vitro responses to these proteins include growth cone collapse. Dynamic changes in the activities of Rho GTPases appear to mediate responses to these cues, although it remains unclear what the changes are in actin filament distribution and dynamic reorganization that result in growth cone collapse. Growth cones in vivo simultaneously encounter positive and negative guidance cues, and thus, growth cone behaviors during axonal pathfinding reflect the complex integration of multiple signaling activities.

Hormonally regulated α4β2δ GABAA receptors are a target for alcohol

Abstract: Here we report that low concentrations of alcohol (1–3 mM) increased Cl− currents gated by a recombinant GABAA receptor, α4β2δ, by 40–50% in Xenopus laevis oocytes. We also found greater hippocampal expression of receptors containing α4 and δ subunits, using a rat model1 of premenstrual2 syndrome (PMS) in which 1–3 mM alcohol preferentially enhanced GABA-gated currents, and low doses of alcohol attenuated anxiety and behavioral reactivity. The alcohol sensitivity of δ-containing receptors may underlie the reinforcing effects of alcohol during PMS, when eye saccade responses to low doses of alcohol are increased2.

Sex, gender, and the work-to-family interface:exploring negative and positive interdependencies

Abstract: This study of full-time managers and professionals examined whether variables selected from theories of the psychology of gender as well as identity, boundary, and role theories explained effects of sex on work-to-family conflict and “positive spillover.” Women experienced higher positive spillover than men, primarily because they were higher in femininity. Although women did not experience different levels of conflict than men, individuals who scored higher on measured family role salience, which was positively related to femininity, experienced lower levels of conflict. Role segmentation not only reduced conflict but also had the unintended consequence of reducing positive spillover.

Computer-aided tissue engineering: overview, scope and challenges.

Abstract: Advances in computer-aided technology and its application with biology, engineering and information science to tissue engineering have evolved a new field of computer-aided tissue engineering (CATE). This emerging field encompasses computer-aided design (CAD), image processing, manufacturing and solid free-form fabrication (SFF) for modelling, designing, simulation and manufacturing of biological tissue and organ substitutes. The present Review describes some salient advances in this field, particularly in computer-aided tissue modeling, computer-aided tissue informatics and computer-aided tissue scaffold design and fabrication. Methodologies of development of CATE modelling from high-resolution non-invasive imaging and image-based three-dimensional reconstruction, and various reconstructive techniques for CAD-based tissue modelling generation will be described. The latest development in SFF to tissue engineering and a framework of bio-blueprint modelling for three-dimensional cell and organ printing will also be introduced.

Model Predictive Control Tuning Methods: A Review

Abstract: This paper provides a review of the available tuning guidelines for model predictive control, from theoretical and practical perspectives. It covers both popular dynamic matrix control and generalized predictive control implementations, along with the more general state-space representation of model predictive control and other more specialized types, such as max-plus-linear model predictive control. Additionally, a section on state estimation and Kalman filtering is included along with auto (self) tuning. Tuning methods covered range from equations derived from simulation/approximation of the process dynamics to bounds on the region of acceptable tuning parameter values.