731 research outputs found
PUMA: Fully Decentralized Uncertainty-aware Multiagent Trajectory Planner with Real-time Image Segmentation-based Frame Alignment
Fully decentralized, multiagent trajectory planners enable complex tasks like
search and rescue or package delivery by ensuring safe navigation in unknown
environments. However, deconflicting trajectories with other agents and
ensuring collision-free paths in a fully decentralized setting is complicated
by dynamic elements and localization uncertainty. To this end, this paper
presents (1) an uncertainty-aware multiagent trajectory planner and (2) an
image segmentation-based frame alignment pipeline. The uncertainty-aware
planner propagates uncertainty associated with the future motion of detected
obstacles, and by incorporating this propagated uncertainty into optimization
constraints, the planner effectively navigates around obstacles. Unlike
conventional methods that emphasize explicit obstacle tracking, our approach
integrates implicit tracking. Sharing trajectories between agents can cause
potential collisions due to frame misalignment. Addressing this, we introduce a
novel frame alignment pipeline that rectifies inter-agent frame misalignment.
This method leverages a zero-shot image segmentation model for detecting
objects in the environment and a data association framework based on geometric
consistency for map alignment. Our approach accurately aligns frames with only
0.18 m and 2.7 deg of mean frame alignment error in our most challenging
simulation scenario. In addition, we conducted hardware experiments and
successfully achieved 0.29 m and 2.59 deg of frame alignment error. Together
with the alignment framework, our planner ensures safe navigation in unknown
environments and collision avoidance in decentralized settings.Comment: 7 pages, 13 figures, conference pape
The CFT dual of AdS gravity with torsion
We consider the Mielke-Baekler model of three-dimensional AdS gravity with
torsion, which has gravitational and translational Chern-Simons terms in
addition to the usual Einstein-Hilbert action with cosmological constant. It is
shown that the topological nature of the model leads to a finite
Fefferman-Graham expansion. We derive the holographic stress tensor and the
associated Ward identities and show that, due to the asymmetry of the left- and
right-moving central charges, a Lorentz anomaly appears in the dual conformal
field theory. Both the consistent and the covariant Weyl and Lorentz anomaly
are determined, and the Wess-Zumino consistency conditions for the former are
verified. Moreover we consider the most general solution with flat boundary
geometry, which describes left-and right-moving gravitational waves on AdS_3
with torsion, and shew that in this case the holographic energy-momentum tensor
is given by the wave profiles. The anomalous transformation laws of the wave
profiles under diffeomorphisms preserving the asymptotic form of the bulk
solution yield the central charges of the dual CFT and confirm the results that
appeared earlier on in the literature. We finally comment on some points
concerning the microstate counting for the Riemann-Cartan black hole.Comment: 17 pages, uses JHEP3.cls. References added, minor errors correcte
Extracellular matrix features discriminate aggressive HER2-positive breast cancer patients who benefit from trastuzumab treatment
We previously identified an extracellular matrix (ECM) gene expression pattern in breast cancer (BC), called ECM3, characterized by a high expression of genes encoding structural ECM proteins. Since ECM is reportedly implicated in response to therapy of BCs, the aim of this work is to investigate the prognostic and predictive value of ECM3 molecular classification in HER2-positive BCs. ECM3 resulted in a robust cluster that identified a subset of 25-37% of HER2-positive tumors with molecular aggressive features. ECM3 was significantly associated with worse prognosis in two datasets of HER2-positive BCs untreated with adjuvant therapy. Analyses carried out on two of our cohorts of patients treated or not with adjuvant trastuzumab showed association of ECM3 with worse prognosis only in patients not treated with trastuzumab. Moreover, investigating a dataset that includes gene profile data of tumors treated with neoadjuvant trastuzumab plus chemotherapy or chemotherapy alone, ECM3 was associated with increased pathological complete response if treated with trastuzumab. In the in vivo experiments, increased diffusion and trastuzumab activity were found in tumors derived from injection of HER2-positive cells with Matrigel that creates an ECM-rich tumor environment. Taken together, these results indicate that HER2-positive BCs classified as ECM3 have an aggressive phenotype but they are sensitive to trastuzumab treatment
Thermoset Shape Memory Polymer Variable Stiffness 4D Robotic Catheters
Variable stiffness catheters are typically composed of an encapsulated core. The core is usually composed of a low melting point alloy (LMPA) or a thermoplastic polymer (TP). In both cases, there is a need to encapsulate the core with an elastic material. This imposes a limit to the volume of variable stiffness (VS) material and limits miniaturization. This paper proposes a new approach that relies on the use of thermosetting materials. The variable stiffness catheter (VSC) proposed in this work eliminates the necessity for an encapsulation layer and is made of a unique biocompatible thermoset polymer with an embedded heating system. This significantly reduces the final diameter, improves manufacturability, and increases safety in the event of complications. The device can be scaled to sub-millimeter dimensions, while maintaining a high stiffness change. In addition, integration into a magnetic actuation system allows for precise actuation of one or multiple tools
Gravity in the 3+1-Split Formalism II: Self-Duality and the Emergence of the Gravitational Chern-Simons in the Boundary
We study self-duality in the context of the 3+1-split formalism of gravity
with non-zero cosmological constant. Lorentzian self-dual configurations are
conformally flat spacetimes and have boundary data determined by classical
solutions of the three-dimensional gravitational Chern-Simons. For Euclidean
self-dual configurations, the relationship between their boundary initial
positions and initial velocity is also determined by the three-dimensional
gravitational Chern-Simons. Our results imply that bulk self-dual
configurations are holographically described by the gravitational Chern-Simons
theory which can either viewed as a boundary generating functional or as a
boundary effective action.Comment: 25 pages; v2: minor improvements, references adde
Elements Related to Heterogeneity of Antibody-Dependent Cell Cytotoxicity in Patients Under Trastuzumab Therapy for Primary Operable Breast Cancer Overexpressing Her2
Preliminary results from a pilot trial on trastuzumab's mechanism of action against operable breast tumors overexpressing Her2 suggested a role for antibody-dependent cell cytotoxicity (ADCC). To examine factors affecting ADCC intensity and variability, we extended this study to the phenotypic and functional analysis of circulating mononuclear cells in 18 patients. ADCC was induced by trastuzumab therapy in 15 of 18 patients (83%). Inability to develop ADCC in three patients did not depend on inadequate levels of trastuzumab because further increase in its concentration in vitro was ineffective. Rather, susceptibility to develop ADCC was fairly predicted by test with trastuzumab before therapy and was correlated to the number of lymphocytes coexpressing CD16 and CD56. Phenotypic analysis at the end of ADCC evaluating down-regulation of CD16, and up-regulation of CD69 and CD107a, confirmed that natural killer (NK) cells and CD56+ T cells were involved in productive engagement of trastuzumab. Also, the killing efficiency of CD16+ lymphocytes was influenced by 158 V/F polymorphism of FcγRIII (CD16), whereas variations of CD247 on NK cells were consistent with trends between ADCC before and after therapy. Complete pathologic response was observed in one patient showing ADCC of outstanding intensity, whereas four cases of partial response showed intermediate ADCC; none of the three patients unable to mount ADCC had significant tumor regression. These data indicate that quantity and lytic efficiency of CD16+ lymphocytes are major factors for ADCC induction by trastuzumab, and confirm that breast cancer responses to short-term trastuzumab monotherapy may depend on involvement of the ADCC mechanism. [Cancer Res 2007;67(24):11991–9
Transcranial optical monitoring for detecting intracranial pressure alterations in children with benign external hydrocephalus: a proof-of-concept study
Hydrocephalus; Optical techniques; PathophysiologyHidrocefalia; Técnicas ópticas; FisiopatologíaHidrocefàlia; Tècniques òptiques; FisiopatologiaSignificance
Benign external hydrocephalus (BEH) is considered a self-limiting pathology with a good prognosis. However, some children present a pathological intracranial pressure (ICP) characterized by quantitative and qualitative alterations (the so-called B-waves) that can lead to neurological sequelae.
Aim
Our purpose was to evaluate whether there were cerebral hemodynamic changes associated with ICP B-waves that could be evaluated with noninvasive neuromonitoring.
Approach
We recruited eleven patients (median age 16 months, range 7 to 55 months) with BEH and an unfavorable evolution requiring ICP monitoring. Bedside, nocturnal monitoring using near-infrared time-resolved and diffuse correlation spectroscopies synchronized to the clinical monitoring was performed.
Results
By focusing on the timing of different ICP patterns that were identified manually by clinicians, we detected significant tissue oxygen saturation (StO2) changes (p = 0.002) and blood flow index (BFI) variability (p = 0.005) between regular and high-amplitude B-wave patterns. A blinded analysis looking for analogs of ICP patterns in BFI time traces achieved 90% sensitivity in identifying B-waves and 76% specificity in detecting the regular patterns.
Conclusions
We revealed the presence of StO2 and BFI variations—detectable with optical techniques—during ICP B-waves in BEH children. Finally, the feasibility of detecting ICP B-waves in hemodynamic time traces obtained noninvasively was shown.This work was realized with the support of the Department of Cirugía and Ciencias Morfológicas of the Universitat Autònoma de Barcelona. The work was supported by the European Union’s Horizon 2020 Research and Innovation Program under the Marie Sklodowska-Curie (Grant No. 675332) (BitMap: brain injury and trauma monitoring using advanced photonics) and the European Union’s Horizon 2020 Research and Innovation Program [Grant No. 101017113 (TinyBrains) and Grant No. 101016087 (VASCOVID)]; Fondo de Investigación Sanitaria (Instituto de Salud Carlos III) (Grant No. PI18/00468); Fundació CELLEX Barcelona, Fundació Mir Puig, Agencia Estatal de Investigación (PHOTOMETABO, Grant No. PID2019106481RBC31); the “Severo Ochoa” Program for Centers of Excelence in R&D (Grant No. CEX2019-000910-S); the Obra social “La Caixa” Foundation (LlumMedBcn), Generalitat de Catalunya (CERCA, AGAUR-2017-SGR-1380, RIS3CAT-001-P-001682 CECH), FEDER EC and LASERLAB EUROPE V (EC H2020 No. 871124); KidsBrainIT (ERANET NEURON); Fundació La Marató de TV3 (Grant Nos. 201724.31 and 201709.31)
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