Use of Atomic Oxygen for Increased Water Contact Angles of Various Polymers for Biomedical Applications

In the low Earth orbit (LEO) space environment, spacecraft surfaces can be altered during atomic oxygen exposure through oxidation and erosion. There can be terrestrial benefits of such interactions, such as the modification of hydrophobic or hydrophilic properties of polymers due to chemical modification and texturing. Such modification of the surface may be useful for biomedical applications. For example, atomic oxygen texturing may increase the hydrophilicity of polymers, such as chlorotrifluoroethylene (Aclar), thus allowing increased adhesion and spreading of cells on textured Petri dishes. The purpose of this study was to determine the effect of atomic oxygen exposure on the hydrophilicity of nine different polymers. To determine whether hydrophilicity remains static after atomic oxygen exposure or changes with exposure, the contact angles between the polymer and a water droplet placed on the polymer s surface were measured. The polymers were exposed to atomic oxygen in a radio frequency (RF) plasma asher. Atomic oxygen plasma treatment was found to significantly alter the hydrophilicity of non-fluorinated polymers. Significant decreases in the water contact angle occurred with atomic oxygen exposure. Fluorinated polymers were found to be less sensitive to changes in hydrophilicity for equivalent atomic oxygen exposures, and two of the fluorinated polymers became more hydrophobic. The majority of change in water contact angle of the non-fluorinated polymers was found to occur with very low fluence exposures, indicating potential cell culturing benefit with short treatment time

Development of a kayak race prediction including environmental and athlete effects

The aim of this study is to produce a simulator for sprint kayak racing which would allow the prediction of race times based on the physiological capabilities and mass of a given athlete. The simulator has been verified using established empirical data for the prediction of environmental effects and has been shown to be accurate, however verification of the physiological model is difficult to do by using general race data. An investigation into the fatigue model which has been implemented shows that further investigation is required to calibrate the simulator and produce more accurate results over a variety of distances. However, the simulator does show quite how sensitive the selection of appropriate level of effort is to the final race time for the 1000m

The Role of the Akt2 Isoform in Th17 Differentiation in Vitro and Peripheral Cd4 T Cell Immune Responses in Vivo

Akt1 and Akt2, isoforms of the serine threonine kinase Akt, are essential for T cell development. However, their role in peripheral T cell differentiation remains undefined. Using germline deletions of either Akt1 or Akt2 in mice, we found that while both are important for Th17 differentiation, the impact of Akt2 loss was greater. Mechanistically, while Akt2-/- Th17 cells were predicted by microarray analysis to have suppressed cholesterol biosynthetic and Il-6 signaling pathways, neither pathway emerged as the primary mechanism through which Akt2 contributes to Th17 differentiation. We also interrogated the role of the well-known Akt target, mTORC1, and found that Akt2-/- Th17 cells were equally sensitive to inhibition of the mTORC1-S6K axis as their WT counterparts. However, Akt2 deficiency was associated with elevated Gfi1 mRNA, which encodes for a known inhibitor of Th17 differentiation, and decreased mir155, which encodes for a miRNA that promotes Th17 differentiation. Furthermore, Akt2 loss has significant in vivo consequences and results in a dampened peripheral T cell response to myelin oligodendrocyte glycoprotein (MOG) immunization. This dampened response was associated with altered Th cell differentiation including a pronounced diminution of inflammatory cytokine production and preferential expansion of regulatory T cells compared to non-T regulatory cells. Using mice with Akt2 loss only in the T cell compartment, Akt2 cKO, we demonstrate that Akt2 promotes Th17 differentiation in both a T cell-intrinsic and T cell-extrinsic manner; Akt2 cKO CD4 T cells had defective IL-17A production in vitro although this defect was milder than that observed in Akt2-/- cells. In vivo, Akt2 cKO splenocytes trended towards decreased cytokine production compared to their WT counterparts after immunization with MOG peptide, suggesting a significant role for Akt2 in non-T cells in shaping the peripheral CD4 T cell response in this model system. Taken together, we identify Akt2 as an important signaling molecule in regulating peripheral CD4 T cell responses. Future studies interrogating the in vivo impact of Akt2 loss in other experimental systems that rely on CD4 T helper cell mediated immunity would provide insight into the contributions of Akt2 to CD4 Th cell differentiation

Anthropomorphic robot finger with multi-point tactile sensation

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2001.Includes bibliographical references (p. 84-95).The goal of this research is to develop the prototype of a tactile sensing platform for anthropomorphic manipulation research. We investigate this problem through the fabrication and simple control of a planar 2-DOF robotic finger inspired by anatomic consistency, self-containment, and adaptability. The robot is equipped with a tactile sensor array based on optical transducer technology whereby localized changes in light intensity within an illuminated foam substrate correspond to the distribution and magnitude of forces applied to the sensor surface plane [58]. The integration of tactile perception is a key component in realizing robotic systems which organically interact with the world. Such natural behavior is characterized by compliant performance that can initiate internal, and respond to external, force application in a dynamic environment. However, most of the current manipulators that support some form of haptic feedback, either solely derive proprioceptive sensation or only limit tactile sensors to the mechanical fingertips. These constraints are due to the technological challenges involved in high resolution, multi-point tactile perception. In this work, however, we take the opposite approach, emphasizing the role of full-finger tactile feedback in the refinement of manual capabilities. To this end, we propose and implement a control framework for sensorimotor coordination analogous to infant-level grasping and fixturing reflexes. This thesis details the mechanisms used to achieve these sensory, actuation, and control objectives, along with the design philosophies and biological influences behind them. The results of behavioral experiments with the tactilely-modulated control scheme are also described. The hope is to integrate the modular finger into an engineered analog of the human hand with a complete haptic system.by Jessica Lauren Banks.S.M

Reconnecting with Joseph and Augusta Dejerine:100 years on

Joseph Dejerine passed away on 28 February 1917 in the midst of a world at war. One hundred years later we celebrate the legacy of this pioneer in neuroscience. In 1895, Joseph Jules Dejerine published the first volume of the seminal work, Anatomie des centres nerveux; volume 2 was published in 1901. In a major section of this tome (vol. 1 pp. 749–80), Joseph Dejerine and his wife and long-term collaborator, Augusta Dejerine-Klumpke, produced a treatise on the white matter pathways of the brain, composed of anatomical descriptions of meticulous detail and beautiful illustration (drawn by H. Gillet) that reflected a combination of the most advanced methodologies of the day and a review of leading neuroscientific research. We have selected and focused this specific output (which is provided for the first time as an English translation in the Supplementary material) from the many that the Dejerines published because its ideas and findings continue to be of relevance to modern neuroscience researchers today; especially those with an interest in connectional anatomy.peer-reviewe