Modelling and experimental investigation of carangiform locomotion for control

We propose a model for planar carangiform swimming based on conservative equations for the interaction of a rigid body and an incompressible fluid. We account for the generation of thrust due to vortex shedding through controlled coupling terms. We investigate the correct form of this coupling experimentally with a robotic propulsor, comparing its observed behavior to that predicted by unsteady hydrodynamics. Our analysis of thrust generation by an oscillating hydrofoil allows us to characterize and evaluate certain families of gaits. Our final swimming model takes the form of a control-affine nonlinear system

The mechanics of undulatory locomotion: the mixed kinematic and dynamic case

This paper studies the mechanics of undulatory locomotion. This type of locomotion is generated by a coupling of internal shape changes to external non-holonomic constraints. Employing methods from geometric mechanics, the authors use the dynamic symmetries and kinematic constraints to develop a specialized form of the dynamic equations which govern undulatory systems. These equations are written in terms of physically meaningful and intuitively appealing variables that show the role of internal shape changes in driving locomotion

Source-Indexed Migration Velocity Analysis with Global Passive Data

The reverse-time migration of global seismic data generated by free-surface multiples is regularly used to constrain the crustal structure, but its accuracy is to a large extent determined by the accuracy of the 3-D background velocity model used for wave propagation. To this improve the velocity model and hence the accuracy of the migrated image, we wish to apply the technique of migration velocity analysis (MVA) to global passive data. Applications of MVA in the active setting typically focus on o ffset- or angle-gather annihilation, a process that takes advantage of data redundancy to form an extended image, and then applies an annihilation operator to determine the success of image formation. Due to the nature of regional-scale passive seismic arrays, it is unlikely that the data in most of these studies will be su cient to form an extended image volume for use in annihilation-based MVA. In order to make use of the sparse and irregular array design of these arrays, we turn towards a shot-pro le moveout scheme for migration velocity analysis introduced by Xie and Yang (2008). In the place of extended image annihilation, we determine the success of the migration velocity model by using a weighted image correlation power norm. We compare pairs of images formed by migrating each teleseismic source by image cross-correlation in the depth direction. We look for a suitable background model by penalizing the amount of correlation power away from zero depth shift. The total weighted correlation power between source-pro le images is then used as the error function and optimized via conjugate gradient. We present the method and a proof-of-concept with 2-D synthetic data

Interferon-γ Stimulates Monocyte Chemotactic Protein-1 Expression by Monocytes

Monocyte chemotactic protein (MCP-1) is a specific monocyte chemoattractant and activating factor produced by both immune cells (mononuclear phagocytes and lymphocytes) and non-immune cells (parenchymal and stromal cells). In order to define the conditions under which human monocytes express MCP-1, monocytes were exposed to IFN-γ, IL- lβ, TNF-α, IL-4 or PHA under serum free conditions. There was no significant MCP-1 production by monocytes following exposure to IL-lβ, TNF-α or IL-4. In contrast, stimulation with IFN-γ resulted in a dose dependent increase in MCP-1 protein and mRNA expression. Simultaneous stimulation with IFN-γ and IL-1β or TNF-α resulted in no further increase in MCP-1 production. It is concluded that IFN-γ, primarily a product of TH1 T lymphocytes, stimulates the expression of MCP-1 by monocytes

RNA-binding proteins to assess gene expression states of co-cultivated cells in response to tumor cells

BACKGROUND: Tumors and complex tissues consist of mixtures of communicating cells that differ significantly in their gene expression status. In order to understand how different cell types influence one another's gene expression, it will be necessary to monitor the mRNA profiles of each cell type independently and to dissect the mechanisms that regulate their gene expression outcomes. RESULTS: In order to approach these questions, we have used RNA-binding proteins such as ELAV/Hu, poly (A) binding protein (PABP) and cap-binding protein (eIF-4E) as reporters of gene expression. Here we demonstrate that the epitope-tagged RNA binding protein, PABP, expressed separately in tumor cells and endothelial cells can be used to discriminate their respective mRNA targets from mixtures of these cells without significant mRNA reassortment or exchange. Moreover, using this approach we identify a set of endothelial genes that respond to the presence of co-cultured breast tumor cells. CONCLUSION: RNA-binding proteins can be used as reporters to elucidate components of operational mRNA networks and operons involved in regulating cell-type specific gene expression in tissues and tumors

Faunal studies of the type Chesteran, Upper Mississippian of southwestern Illinois

48 p., 7 pl., 4 fig.http://paleo.ku.edu/contributions.htm

Recording advances for neural prosthetics

An important challenge for neural prosthetics research is to record from populations of neurons over long periods of time, ideally for the lifetime of the patient. Two new advances toward this goal are described, the use of local field potentials (LFPs) and autonomously positioned recording electrodes. LFPs are the composite extracellular potential field from several hundreds of neurons around the electrode tip. LFP recordings can be maintained for longer periods of time than single cell recordings. We find that similar information can be decoded from LFP and spike recordings, with better performance for state decodes with LFPs and, depending on the area, equivalent or slightly less than equivalent performance for signaling the direction of planned movements. Movable electrodes in microdrives can be adjusted in the tissue to optimize recordings, but their movements must be automated to be a practical benefit to patients. We have developed automation algorithms and a meso-scale autonomous electrode testbed, and demonstrated that this system can autonomously isolate and maintain the recorded signal quality of single cells in the cortex of awake, behaving monkeys. These two advances show promise for developing very long term recording for neural prosthetic applications

SLC/CCL21-mediated anti-tumor responses require IFNγ, MIG/CXCL9 and IP-10/CXCL10

BACKGROUND: SLC/CCL21, normally expressed in high endothelial venules and in T cell zones of spleen and lymph nodes, strongly attracts T cells and dendritic cells (DC). We have previously shown that SLC/CCL21-mediated anti-tumor responses are accompanied by significant induction of IFNγ and the CXC chemokines, monokine induced by IFNγ (MIG/CXCL9) and IFNγ-inducible protein-10 (IP-10/CXCL10). RESULTS: We assessed the importance of IFNγ, IP-10/CXCL10 and MIG/CXCL9 in SLC/CCL21 therapy. In vivo depletion of IP-10/CXCL10, MIG/CXCL9 or IFNγ significantly reduced the anti-tumor efficacy of SLC/CCL21. Assessment of cytokine production at the tumor site showed an interdependence of IFNγ, MIG/CXCL9 and IP-10/CXCL10; neutralization of any one of these cytokines caused a concomitant decrease in all three cytokines. Similarly, neutralization of any one of these cytokines led to a decrease in the frequency of CXCR3(+ve )T cells and CD11c(+ve )DC at the tumor site. CONCLUSION: These findings indicate that the full potency of SLC/CCL21-mediated anti-tumor responses require in part the induction of IFNγ, MIG/CXCL9 and IP-10/CXCL10