168 research outputs found
Robot and robot system
A robot and robot system that are capable of functioning in a zero-gravity environment are provided. The robot can include a body having a longitudinal axis and having a control unit and a power source. The robot can include a first leg pair including a first leg and a second leg. Each leg of the first leg pair can be pivotally attached to the body and constrained to pivot in a first leg pair plane that is substantially perpendicular to the longitudinal axis of the body
Lirot.ai: A Novel Platform for Crowd-Sourcing Retinal Image Segmentations
Introduction: For supervised deep learning (DL) tasks, researchers need a
large annotated dataset. In medical data science, one of the major limitations
to develop DL models is the lack of annotated examples in large quantity. This
is most often due to the time and expertise required to annotate. We introduce
Lirot. ai, a novel platform for facilitating and crowd-sourcing image
segmentations. Methods: Lirot. ai is composed of three components; an iPadOS
client application named Lirot. ai-app, a backend server named Lirot. ai-server
and a python API name Lirot. ai-API. Lirot. ai-app was developed in Swift 5.6
and Lirot. ai-server is a firebase backend. Lirot. ai-API allows the management
of the database. Lirot. ai-app can be installed on as many iPadOS devices as
needed so that annotators may be able to perform their segmentation
simultaneously and remotely. We incorporate Apple Pencil compatibility, making
the segmentation faster, more accurate, and more intuitive for the expert than
any other computer-based alternative. Results: We demonstrate the usage of
Lirot. ai for the creation of a retinal fundus dataset with reference
vasculature segmentations. Discussion and future work: We will use active
learning strategies to continue enlarging our retinal fundus dataset by
including a more efficient process to select the images to be annotated and
distribute them to annotators
Microgravity, Mesh-Crawling Legged Robots
The design, fabrication, and microgravity flight-testing are part of a continuing development of palm-sized mobile robots that resemble spiders (except that they have six legs apiece, whereas a spider has eight legs). Denoted SpiderBots (see figure), they are prototypes of proposed product line of relatively inexpensive walking robots that could be deployed in large numbers to function cooperatively in construction, repair, exploration, search, and rescue activities in connection with exploration of outer space and remote planets
Automated quantification of mitral valve geometry on multi-slice computed tomography in patients with dilated cardiomyopathy: Implications for transcatheter mitral valve replacement
Objectives The primary aim of this study was to quantify the dimensions and geometry of the mitral valve complex in patients with dilated cardiomyopathy and significant mitral regurgitation. The secondary aim was to evaluate the validity of an automated segmentation algorithm for assessment of the mitral valve compared to manual assessment on computed tomography. Background Transcatheter mitral valve replacement (TMVR) is an evolving technique which relies heavily on the lengthy evaluation of cardiac computed tomography (CT) datasets. Limited data is available on the dimensions and geometry of the mitral valve in pathological states throughout the cardiac cycle, which may have implications for TMVR device design, screening of suitable candidates and annular sizing prior to TMVR. Methods A retrospective study of 15 of patients with dilated cardiomyopathy who had undergone full multiphase ECG gated cardiac CT. A comprehensive evaluation of mitral valve geometry was performed at 10 phases of the cardiac cycle using the recommended D-shaped mitral valve annulus (MA) segmentation model using manual and automated CT interpretation platforms. Mitral annular dimensions and geometries were compared between manual and automated methods. Results Mitral valve dimensions in patients with dilated cardiomyopathy were similar to previously reported values (MAarea Diastole: 12.22 ± 1.90 cm2), with dynamic changes in size and geometry between systole and diastole of up to 5%. The distance from the centre of the MA to the left ventricular apex demonstrated moderate agreement between automated and manual methods (ρc = 0.90) with other measurements demonstrating poor agreement between the two methods (ρc = 0.75–0.86). Conclusions Variability of mitral valve annulus measurements are small during the cardiac cycle. Novel automated algorithms to determine cardiac cycle variations in mitral valve geometry may offer improved segmentation accuracy as well as improved CT interpretation times
PhysioZoo: The Open Digital Physiological Biomarkers Resource
PhysioZoo is a collaborative platform designed for the analysis of continuous
physiological time series. The platform currently comprises four modules, each
consisting of a library, a user interface, and a set of tutorials: (1)
PhysioZoo HRV, dedicated to studying heart rate variability (HRV) in humans and
other mammals; (2) PhysioZoo SPO2, which focuses on the analysis of digital
oximetry biomarkers (OBM) using continuous oximetry (SpO2) measurements from
humans; (3) PhysioZoo ECG, dedicated to the analysis of electrocardiogram (ECG)
time series; (4) PhysioZoo PPG, designed to study photoplethysmography (PPG)
time series. In this proceeding, we introduce the PhysioZoo platform as an open
resource for digital physiological biomarkers engineering, facilitating
streamlined analysis and data visualization of physiological time series while
ensuring the reproducibility of published experiments. We welcome researchers
to contribute new libraries for the analysis of various physiological time
series, such as electroencephalography, blood pressure, and phonocardiography.
You can access the resource at physiozoo.com. We encourage researchers to
explore and utilize this platform to advance their studies in the field of
continuous physiological time-series analysis.Comment: 4 pages, 2 figure, 50th Computing in Cardiology conference in
Atlanta, Georgia, USA on 1st - 4th October 202
Autonomic modulation in patients with heart failure increases beat-to-beat variability of ventricular action potential duration
Background: Exaggerated beat-to-beat variability of ventricular action potential duration (APD) is linked to arrhythmogenesis. Sympathetic stimulation has been shown to increase QT interval variability, but its effect on ventricular APD in humans has not been determined.Methods and Results: Eleven heart failure patients with implanted bi-ventricular pacing devices had activation–recovery intervals (ARI, surrogate for APD) recorded from LV epicardial electrodes under constant RV pacing. Sympathetic activity was increased using a standard autonomic challenge (Valsalva) and baroreceptor indices were applied to determine changes in sympathetic stimulation. Two Valsalvas were performed for each study and were repeated, both off and on bisoprolol. In addition sympathetic nerve activity (SNA) was measured from skin electrodes on the thorax using a novel validated method. Autonomic modulation significantly increased mean short-term variability in ARI; off bisoprolol mean STV increased from 3.73 ± 1.3 to 5.27 ± 1.04 ms (p = 0.01), on bisoprolol mean STV of ARI increased from 4.15 ± 1.14 to 4.62 ± 1 ms (p = 0.14). Adrenergic indices of the Valsalva demonstrated significantly reduced beta-adrenergic function when on bisoprolol (Δ pressure recovery time, p = 0.04; Δ systolic overshoot in Phase IV, p = 0.05). Corresponding increases in SNA from rest both off (1.4 uV, p < 0.01) and on (0.7 uV, p < 0.01) bisoprolol were also seen.Conclusions: Beat-to-beat variability of ventricular APD increases during brief periods of increased sympathetic activity in patients with heart failure. Bisoprolol reduces, but does not eliminate, these effects. This may be important in the genesis of ventricular arrhythmias in heart failure patients
The role of conduction system pacing in patients with atrial fibrillation
Conduction system pacing (CSP) has emerged as a promising novel delivery method for Cardiac Resynchronisation Therapy (CRT), providing an alternative to conventional biventricular epicardial (BiV) pacing in indicated patients. Despite increasing popularity and widespread uptake, CSP has rarely been specifically examined in patients with atrial fibrillation (AF), a cohort which forms a significant proportion of the heart failure (HF) population. In this review, we first examine the mechanistic evidence for the importance of sinus rhythm (SR) in CSP by allowing adjustment of atrioventricular delays (AVD) to achieve the optimal electrical response, and thus, whether the efficacy of CSP may be significantly attenuated compared to conventional BiV pacing in the presence of AF. We next evaluate the largest clinical body of evidence in this field, related to patients receiving CSP following atrioventricular nodal ablation (AVNA) for AF. Finally, we discuss how future research may be designed to address the vital question of how effective CSP in AF patients is, and the potential hurdles we may face in delivering such studies
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