Behavioral Outputs of Fragile-X Autistic Mice Exposed to Open-Field, Randomized, Short-Term Visual Stimuli

Animal models of different neurological disorders are required for studying the pathophysiology of these diseases, and for potential development of pharmacological and behavioral treatments. The scientific community often uses mouse models for behavior studies due to their powerful genetic tools and low cost. However, subjective measurement techniques are often used when analyzing mice for behavioral traits which often results in discrepancies in results. An automated tracking software would aim to eliminate these discrepancies and subjective analysis. This lab has developed a software program which offered an ability to automatically collect open-field behavioral data with simultaneous on-line analysis. Python, an open sourced programming language, and OpenCV, an open sourced computer vision library, were used to create this novel tracking software. Wild type and transgenic Fragile-X mice were put into an open field environment and allowed to freely interact with it. Relative positioning and cross sectional area of a mouse were automatically tracked and quantified. In addition, an open-field visual stimulation paradigm was used, which is intended to be used to test visual perception, visual learning, and behavior in mice. A statistically significant difference was found between the transgenic and wild type mice in how they respond to both novel and habituated stimulation. The transgenic mice reacted for a longer period of time after novel stimulation with no decrease in response over the 45 minutes of trials while wild type mice stopped responding immediately after stimulation ended and have a decreased response over time. The most likely cause of these responses is a difficulty learning in fragile-X mouse models as well as longer firing time for their neurons

Mindfulness Meditation Activates Altruism.

Clinical evidence suggests that mindfulness meditation reduces anxiety, depression, and stress, and improves emotion regulation due to modulation of activity in neural substrates linked to the regulation of emotions and social preferences. However, less was known about whether mindfulness meditation might alter pro-social behavior. Here we examined whether mindfulness meditation activates human altruism, a component of social cooperation. Using a simple donation game, which is a real-world version of the Dictator's Game, we randomly assigned 326 subjects to a mindfulness meditation online session or control and measured their willingness to donate a portion of their payment for participation as a charitable donation. Subjects who underwent the meditation treatment donated at a 2.61 times higher rate than the control (p = 0.005), after controlling for socio-demographics. We also found a larger treatment effect of meditation among those who did not go to college (p < 0.001) and those who were under 25 years of age (p < 0.001), with both subject groups contributing virtually nothing in the control condition. Our results imply high context modularity of human altruism and the development of intervention approaches including mindfulness meditation to increase social cooperation, especially among subjects with low baseline willingness to contribute

Exploring the Dynamics of Base-Excited Structures Impacting a Rigid Stop

This paper explores the nonlinear dynamics of a multidegree of freedom (MDoF) structure impacting a rigid stop. The contact mechanics is simplified by continuous sigmoid function idealisation of a lossless spring. By introducing a smooth nonlinear formulation, we avoid the computational expense of event-driven, piecewise, nonsmooth dynamics. A large parametric study using high-performance computing is undertaken. The nondimensional equations of motion suggest one primary structural parameter, contact-to-storey stiffness ratio, and two excitation parameters, nondimensional ground amplitude and frequency. Bifurcation plots indicate an extremely rich and complex behaviour, particularly in the cases where at least two-floor degrees of freedom (DoFs) impact the stop and when the contact-to-storey stiffness ratio is large. When considering interstorey drift as a performance measure, period-1 impacting solutions are generally favourable when compared to an analogous nonimpacting case. This paper also discusses whether chaotic impacting can be favourable. Finally, we consider the question of whether higher modes are significantly excited, at a linear resonance, for impacting solutions to this system

Exploring the Dynamics of Base-Excited Structures Impacting a Rigid Stop

This paper explores the nonlinear dynamics of a multidegree of freedom (MDoF) structure impacting a rigid stop. The contact mechanics is simplified by continuous sigmoid function idealisation of a lossless spring. By introducing a smooth nonlinear formulation, we avoid the computational expense of event-driven, piecewise, nonsmooth dynamics. A large parametric study using high-performance computing is undertaken. The nondimensional equations of motion suggest one primary structural parameter, contact-to-storey stiffness ratio, and two excitation parameters, nondimensional ground amplitude and frequency. Bifurcation plots indicate an extremely rich and complex behaviour, particularly in the cases where at least two-floor degrees of freedom (DoFs) impact the stop and when the contact-to-storey stiffness ratio is large. When considering interstorey drift as a performance measure, period-1 impacting solutions are generally favourable when compared to an analogous nonimpacting case. This paper also discusses whether chaotic impacting can be favourable. Finally, we consider the question of whether higher modes are significantly excited, at a linear resonance, for impacting solutions to this system

Vertical Color Maps: A Data Independent Alternative to Floor Plan Maps

Location sharing in indoor environments is limited by the sparse availability of indoor positioning and lack of geographical building data. Recently, several solutions have begun to implement digital maps for use in indoor space. The map design is often a variant of floor-plan maps. Whereas massive databases and GIS exist for outdoor use, the majority of indoor environments are not yet available in a consistent digital format. This dearth of indoor maps is problematic, as navigating multistorey buildings is known to create greater difficulty in maintaining spatial orientation and developing accurate cognitive maps. The development of standardized, more intuitive indoor maps can address this vexing problem. The authors therefore present an alternative solution to current indoor map design that explores the possibility of using colour to represent the vertical dimension on the map. Importantly, this solution is independent of existing geographical building data. The new design is hypothesized to do a better job than existing solutions of facilitating the integration of indoor spaces. Findings from a human experiment with 251 participants demonstrate that the vertical colour map is a valid alternative to the regular floor-plan map

Use of growth factors and adhesive ligands to promote connective tissue progenitor colony formation from fresh marrow

Thesis (Ph. D.)--Massachusetts Institute of Technology, Biological Engineering Division, 2008.Includes bibliographical references.The current gold standard for bone graft material is autologous bone, which provides mechanical support, possesses factors that promote bone formation, and contains connective tissue progenitors (CTPs), a heterogeneous population of connective tissue stem and progenitor cells that contribute to neotissue formation. A major limitation to autologous bone grafts is the risk of surgical complications associated with graft harvesting as well as significant donor-site morbidity. Available bone graft substitutes are not as efficacious as autologous bone, resulting in a prescient need for improved bone grafting materials. A promising tissue engineering approach involves the use of bioactive biomaterials that can promote the selective retention of CTPs from pre-seeded autologous bone marrow. When presented in a tethered form, EGF has been shown to promote the survival and enhance the adhesion of culture expanded CTPs. Therefore, the hypothesis of this work was that tethered EGF could be used to enhance the retention of osteogenic CTPs from freshly aspirated bone marrow. Numerous adhesion ligands and growth factors have been investigated for use as candidates for the functionalization of bioactive materials. In this work, we showed that synergy-RGD peptides, which incorporate the putative synergy site on fibronectin, can promote cell adhesion through both a5pl and av33 integrins. We then investigated the effects of tethered EGF on CTP colony formation in the context of defined adhesion environments using a functionalizable comb copolymer. We found that tethered EGF increased the colony forming efficiency of CTPs from fresh human marrow when cell attachment was promoted by either non-specific protein adsorption, fibronectin pre adsorption, or through the synergy-RGD ligand. In contrast, soluble EGF did not increase colony formation, demonstrating the importance of the modality of ligand presentation.(cont.) Quantitative image analysis also suggested that while tethered EGF did not promote increased osteogenesis at early times after cell seeding tethered EGF may induce the proliferation and migration of cells within osteogenic colonies. These results provide important insight into both the study of the effect of EGF on CTP behavior, as well as the use of tethered EGF as a potential ligand for use in biomaterials that promote the selective retention of CTPs.by Nicholas A. Marcantonio.Ph.D

Structural capacity assessment of corroded RC bridge piers

A new numerical model is developed that enables simulation of the nonlinear flexural response of reinforced concrete (RC) components and sections with corroded reinforcement. The numerical model employs a displacement based beam-column element using the classical Hermitian shape function. The material nonlinearity is accounted for by updating element stiffness matrices using the moment-curvature response of the element section considering uniform stiffness over the element. The cover concrete strength is adjusted to account for corrosion induced cover cracking and the core confined concrete strength and ductility are adjusted to account for corrosion induced damage to the transverse reinforcement. The numerical model is validated against a bench mark experiment on a corroded RC column subject to lateral cyclic loading. The verified model is then used to explore the impact of corrosion on the inelastic response and the residual capacity of corroded RC sections. The results show that considering the effect of corrosion damage on RC sections changes the failure mode of RC columns