41 research outputs found
Dual use display systems for telerobotics
This paper describes a telerobotics display system, the Multi-mode Manipulator Display System (MMDS), that has applications for a variety of remotely controlled tasks. Designed primarily to assist astronauts with the control of space robotics systems, the MMDS has applications for ground control of space robotics as well as for toxic waste cleanup, undersea, remotely operated vehicles, and other environments which require remote operations. The MMDS has three modes: (1) Manipulator Position Display (MPD) mode, (2) Joint Angle Display (JAD) mode, and (3) Sensory Substitution (SS) mode. These three modes are discussed in the paper
Onboarding at the City of North St Paul
Report and poster completed by students enrolled in HRIR 8034: Employee Development-Creating a Competitive Advantage, taught by Dr. Stacy Doepner-Hove in fall 2013.This project was completed as part of the 2013-2014 Resilient Communities Project (rcp.umn.edu) partnership with the City of North St. Paul. The City of North St. Paul hired a new city manager who wanted to make changes in workplace culture and place an emphasis on staff satisfaction. Project lead Jason Ziemer collaborated with students in Dr. Stacy Doepner-Hove’s HRIR 8034: Employee Development–Creating a Competitive Advantage to look at these new initiatives. The students developed processes for bringing in new employees and outlined methods for implementing and evaluating those processes. This is one of five reports completed by student teams on this topic for this course. The final report and a poster summarizing the work of all five groups are available.This project was supported by the Resilient Communities Project (RCP), a program at the University of Minnesota whose mission is to connect communities in Minnesota with U of MN faculty and students to advance community resilience through collaborative, course-based projects. RCP is a program of the Center for Urban and Regional Affairs (CURA). More information at http://www.rcp.umn.edu
Real-time Optimized Rendezvous on Nonholonomic Resource-Constrained Robots
Abstract In this work, we consider a group of differential-wheeled robots endowed with noisy relative positioning capabilities. We develop a decentralized approach based on a receding horizon controller to generate, in real-time, trajectories that guarantee the convergence of our robots to a common location (i.e. rendezvous). Our receding horizon controller is tailored around two numerical optimization methods: the hybrid-state A * and trust-region algorithms. To validate both methods and test their robustness to computational delays, we perform exhaustive experiments on a team of four real mobile robots equipped with relative positioning hardware
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Effects of Delta9-tetrahydrocannabivarin on [35S]GTPgammaS binding in mouse brain cerebellum and piriform cortex membranes
BACKGROUND AND PURPOSE: We have recently shown that the phytocannabinoid Delta9-tetrahydrocannabivarin (Delta9-THCV) and the CB1 receptor antagonist AM251 increase inhibitory neurotransmission in mouse cerebellum and also exhibit anticonvulsant activity in a rat piriform cortical (PC) model of epilepsy. Possible mechanisms underlying cannabinoid actions in the CNS include CB1 receptor antagonism (by displacing endocannabinergic tone) or inverse agonism at constitutively active CB1 receptors. Here, we investigate the mode of cannabinoid action in [35S]GTPgammaS binding assays. EXPERIMENTAL APPROACH: Effects of Delta9-THCV and AM251 were tested either alone or against WIN55,212-2-induced increases in [35S]GTPgammaS binding in mouse cerebellar and PC membranes. Effects on non-CB receptor expressing CHO-D2 cell membranes were also investigated. KEY RESULTS :Delta9-THCV and AM251 both acted as potent antagonists of WIN55,212-2-induced increases in [35S]GTPgammaS binding in cerebellar and PC membranes (Delta9-THCV: pA2=7.62 and 7.44 respectively; AM251: pA2=9.93 and 9.88 respectively). At micromolar concentrations, Delta9-THCV or AM251 alone caused significant decreases in [35S]GTPgammaS binding; Delta9-THCV caused larger decreases than AM251. When applied alone in CHO-D2 membranes, Delta9-THCV and AM251 also caused concentration-related decreases in G protein activity. CONCLUSIONS AND IMPLICATIONS: Delta9-THCV and AM251 act as CB1 receptors antagonists in the cerebellum and PC, with AM251 being more potent than Delta9-THCV in both brain regions. Individually, Delta9-THCV or AM251 exhibited similar potency at CB1 receptors in the cerebellum and the PC. At micromolar concentrations, Delta9-THCV and AM251 caused a non-CB receptor-mediated depression of basal [35S]GTPgammaS binding
Activation of the Cannabinoid CB1 Receptor May Involve a W6.48/F3.36 Rotamer Toggle Switch
The cannabinoid CB1 receptor, a member of the Rhodopsin (Rho) family of G protein coupled receptors (GPCRs), exhibits high levels of constitutive activity. In contrast, Rho exhibits an exquisite lack of constitutive activity. In Rho, W6.48(265) on transmembrane helix 6 (TMH6) is flanked by aromatic residues at positions i-4 (F6.44) and i + 3 (Y6.51), while in CB1 the residues i-4 and i + 3 to W6.48 are leucines (L6.44 and L6.51). Based upon spectroscopic evidence, W6.48 has been proposed to undergo a rotamer switch (χ1 g+ →trans) upon activation of Rho. In the work reported here, the biased Monte Carlo method, Conformational Memories (CM) was used to test the hypothesis that the high constitutive activity exhibited by CB1 may be due, in part, to the lack of aromatic residues i-4 and i + 3 from W6.48. In this work, the W6.48 rotamer shift (χ1 g+ →trans) was used as the criterion for activation. Conformational Memories (CM) calculations on WT CB1 TMH6 and L6.44F and L6.51Y mutant TMH6s revealed that an aromatic residue at 6.44 tends to disfavor the W6.48 χ1 g+ →trans transition and an aromatic residue at 6.51 would require a concomitant movement of the Y6.51 χ1 from trans→g+ when the W6.48 χ1 undergoes a g+ →trans shift. In contrast, CM calculations on WT CB1 TMH6 revealed that the presence of leucines at 6.44 and 6.51 provide W6.48 with greater conformational mobility, with a W6.48 transχ1 preferred. Conformational Memories calculations also revealed that the W6.48 χ1 g+ →trans transition in WT CB1 TMH6 is correlated with the degree of kinking in TMH6. The average proline kink angles for TMH6 were higher for helices with a W6.48 g+ χ1 than for those with a W6.48 transχ1. These results are consistent with experimental evidence that TMH6 straightens during activation. Transmembrane helix (TMH) bundle models of the inactive (R) and active (R*) states of CB1 were then probed for interactions that may constrain W6.48 in the inactive state of CB1. These studies revealed that F3.36 (transχ1) helps to constrain W6.48 in a g+ χ1 in the inactive (R) state of CB1. In the R* state, these studies suggest that F3.36 must assume a g+ χ1 in order to allow W6.48 to shift to a transχ1. These results suggest that the W6.48/F3.36 interaction may act as the ‘toggle switch’ for CB1 activation, with W6.48 χ1 g+/F3.36 χ1 trans representing the inactive (R) and W6.48 χ1 trans/F3.36 χ1 g+ representing the active (R*) state of CB1