853 research outputs found

    Collaborative Gaze Channelling for Improved Cooperation During Robotic Assisted Surgery

    Get PDF
    The use of multiple robots for performing complex tasks is becoming a common practice for many robot applications. When different operators are involved, effective cooperation with anticipated manoeuvres is important for seamless, synergistic control of all the end-effectors. In this paper, the concept of Collaborative Gaze Channelling (CGC) is presented for improved control of surgical robots for a shared task. Through eye tracking, the fixations of each operator are monitored and presented in a shared surgical workspace. CGC permits remote or physically separated collaborators to share their intention by visualising the eye gaze of their counterparts, and thus recovers, to a certain extent, the information of mutual intent that we rely upon in a vis-à-vis working setting. In this study, the efficiency of surgical manipulation with and without CGC for controlling a pair of bimanual surgical robots is evaluated by analysing the level of coordination of two independent operators. Fitts' law is used to compare the quality of movement with or without CGC. A total of 40 subjects have been recruited for this study and the results show that the proposed CGC framework exhibits significant improvement (p<0.05) on all the motion indices used for quality assessment. This study demonstrates that visual guidance is an implicit yet effective way of communication during collaborative tasks for robotic surgery. Detailed experimental validation results demonstrate the potential clinical value of the proposed CGC framework. © 2012 Biomedical Engineering Society.link_to_subscribed_fulltex

    松本歯科大学学会会則

    Get PDF
    © Springer Nature Singapore Pte Ltd 2020. Railway industries are facing greater technical and economic challenges to increase the train speeds and hauling capacity of the trains to cope up with the growing population and increasing traffic problems. However, increasing dynamic stresses from the passage of faster and heavy haul trains progressively degrades the ballast layer and other track substructure layers which inevitably leads to excessive settlement and track instability. Nowadays, heavier concrete sleepers used in most of the ballasted tracks are subjected to even greater stresses and faster deterioration. Under Sleeper Pads (USPs) are resilient pads installed at the bottom face of concrete sleepers to increase the degree of vertical elasticity in the track structure and also with the intention of enhancing sleeper–ballast interaction to minimize dynamic stresses and subsequent track deterioration. In this study, cyclic loads from fast and heavy haul trains have been simulated using a large-scale Process Simulation Prismoidal Triaxial Apparatus (PSPTA) to investigate the performance of ballast improved by the USPs. The laboratory results indicate that the inclusion of USP at the harder interface of concrete sleeper-ballast significantly curtails the stresses transmitted and minimizes the amount of plastic deformation and degradation of ballast

    Theory of Multidimensional Solitons

    Full text link
    We review a number of topics germane to higher-dimensional solitons in Bose-Einstein condensates. For dark solitons, we discuss dark band and planar solitons; ring dark solitons and spherical shell solitons; solitary waves in restricted geometries; vortex rings and rarefaction pulses; and multi-component Bose-Einstein condensates. For bright solitons, we discuss instability, stability, and metastability; bright soliton engineering, including pulsed atom lasers; solitons in a thermal bath; soliton-soliton interactions; and bright ring solitons and quantum vortices. A thorough reference list is included.Comment: review paper, to appear as Chapter 5a in "Emergent Nonlinear Phenomena in Bose-Einstein Condensates: Theory and Experiment," edited by P. G. Kevrekidis, D. J. Frantzeskakis, and R. Carretero-Gonzalez (Springer-Verlag

    Dynamics of growth and weight transitions in a pediatric cohort from India

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>There is paucity of information regarding time trends of weight status in children from rapidly developing economies like India. The aim of the study was to analyse the dynamics of growth and weight transitions in a cohort of school children from India.</p> <p>Methods</p> <p>A population of 25 228 children was selected using stratified random sampling method from schools in a contiguous area in Ernakulam District, Kerala, India. Weight and height were measured at two time points, one in 2003-04 and another in 2005-06. The paired data of 12 129 children aged 5-16 years were analysed for the study.</p> <p>Results</p> <p>The mean interval between the two surveys was 2.02 ± 0.32 years. The percentage of underweight, normal weight, overweight and obese children in the year 2003-04 were 38.4%, 56.6%, 3.7%, and 1.3% respectively. The corresponding figures in year 2005-06 were 29.9%, 63.6%, 4.8% and 1.7% respectively. Among the underweight children, 34.8% migrated to normal weight status and 0.1% migrated to overweight status. Conversion of underweight to normal weight predominated in urban area and girls. Among the normal weight children, 8.6% migrated to underweight, 4.1% migrated to overweight and 0.4% migrated to obesity. Conversion of normal weight to overweight status predominated in urban area, private schools and boys. Conversion of normal weight to underweight predominated in rural area, government schools and boys. Among the overweight children, 26.7% migrated to normal weight status, 16.4% became obese and 56.9% retained their overweight status. Of the obese children, 6.2% improved to normal weight status, 25.3% improved to overweight status and 68.5% remained as obese in 2005-06. There was significant difference in trends between socio demographic subgroups regarding conversion of underweight status to normal weight as well as normal weight status to overweight.</p> <p>Conclusion</p> <p>The study population is experiencing rapid growth and nutritional transitions characterised by a decline in the underweight population coupled with an escalation of the overweight population. The heterogeneous nature of this transition appears to be due to differences in socio demographic factors.</p

    Obatoclax induces Atg7-dependent autophagy independent of beclin-1 and BAX/BAK

    Get PDF
    Direct pharmacological targeting of the anti-apoptotic B-cell lymphoma-2 (BCL-2) family is an attractive therapeutic strategy for treating cancer. Obatoclax is a pan-BCL-2 family inhibitor currently in clinical development. Here we show that, although obatoclax can induce mitochondrial apoptosis dependent on BCL-2 associated x protein/BCL-2 antagonist killer (BAX/BAK) consistent with its on-target pharmacodynamics, simultaneous silencing of both BAX and BAK did not abolish acute toxicity or loss of clonogenicity. This is despite complete inhibition of apoptosis. Obatoclax dramatically reduced viability without inducing loss of plasma membrane integrity. This was associated with rapid processing of light chain-3 (LC3) and reduction of S6 kinase phosphorylation, consistent with autophagy. Dramatic ultrastructural vacuolation, not typical of autophagy, was also induced. Silencing of beclin-1 failed to prevent LC3 processing, whereas knockout of autophagy-related (Atg)7 abolished LC3 processing but failed to prevent obatoclax-induced loss of clonogenicity or ultrastructural changes. siRNA silencing of Atg7 in BAX/BAK knockout mouse embryonic fibroblasts did not prevent obatoclax-induced loss of viability. Cells selected for obatoclax resistance evaded apoptosis independent of changes in BCL-2 family expression and displayed reduced LC3 processing. In summary, obatoclax exhibits BAX- and BAK-dependent and -independent mechanisms of toxicity and activation of autophagy. Mechanisms other than autophagy and apoptosis are blocked in obatoclax resistant cells and contribute significantly to obatoclax's anticancer efficacy

    T Cells Enhance Stem-Like Properties and Conditional Malignancy in Gliomas

    Get PDF
    Small populations of highly tumorigenic stem-like cells (cancer stem cells; CSCs) can exist within, and uniquely regenerate cancers including malignant brain tumors (gliomas). Many aspects of glioma CSCs (GSCs), however, have been characterized in non-physiological settings.We found gene expression similarity superiorly defined glioma "stemness", and revealed that GSC similarity increased with lower tumor grade. Using this method, we examined stemness in human grade IV gliomas (GBM) before and after dendritic cell (DC) vaccine therapy. This was followed by gene expression, phenotypic and functional analysis of murine GL26 tumors recovered from nude, wild-type, or DC-vaccinated host brains.GSC similarity was specifically increased in post-vaccine GBMs, and correlated best to vaccine-altered gene expression and endogenous anti-tumor T cell activity. GL26 analysis confirmed immune alterations, specific acquisition of stem cell markers, specifically enhanced sensitivity to anti-stem drug (cyclopamine), and enhanced tumorigenicity in wild-type hosts, in tumors in proportion to anti-tumor T cell activity. Nevertheless, vaccine-exposed GL26 cells were no more tumorigenic than parental GL26 in T cell-deficient hosts, though they otherwise appeared similar to GSCs enriched by chemotherapy. Finally, vaccine-exposed GBM and GL26 exhibited relatively homogeneous expression of genes expressed in progenitor cells and/or differentiation.T cell activity represents an inducible physiological process capable of proportionally enriching GSCs in human and mouse gliomas. Stem-like gliomas enriched by strong T cell activity, however, may differ from other GSCs in that their stem-like properties may be disassociated from increased tumor malignancy and heterogeneity under specific host immune conditions
    corecore