76 research outputs found
A System-on-Chip solution for a low power active capsule endoscope with therapeutic capabilities for clip application in the gastrointestinal tract
This paper addresses the circuit implementation challenges resulting from the integration of a therapeutic clip in a magnetically maneuverable wireless capsule intended for colonoscopy. To deal with the size constraints typical of a capsule endoscope, an Application Specific Integrated Circuit (ASIC) has been designed specifically to habilitate the release of the therapeutic clip. The ASIC is a complete System on Chip (SoC) that incorporates a circuit for the low power release of the clip, thus overcoming the limitations of the power supply system. With a size of 14mm2, the ASIC can be incorporated in practically any capsule endoscope, consuming only an idle-state power of 1.5mW
Frontiers of robotic endoscopic capsules: a review
Digestive diseases are a major burden for society and healthcare systems, and with an aging population, the importance of their effective management will become critical. Healthcare systems worldwide already struggle to insure quality and affordability of healthcare delivery and this will be a significant challenge in the midterm future. Wireless capsule endoscopy (WCE), introduced in 2000 by Given Imaging Ltd., is an example of disruptive technology and represents an attractive alternative to traditional diagnostic techniques. WCE overcomes conventional endoscopy enabling inspection of the digestive system without discomfort or the need for sedation. Thus, it has the advantage of encouraging patients to undergo gastrointestinal (GI) tract examinations and of facilitating mass screening programmes. With the integration of further capabilities based on microrobotics, e.g. active locomotion and embedded therapeutic modules, WCE could become the key-technology for GI diagnosis and treatment. This review presents a research update on WCE and describes the state-of-the-art of current endoscopic devices with a focus on research-oriented robotic capsule endoscopes enabled by microsystem technologies. The article also presents a visionary perspective on WCE potential for screening, diagnostic and therapeutic endoscopic procedures
Beerenobstanbau - Entwicklung wirtschaftlicher Anbauverfahren von Beerenobst mit Überdachung
Hauptkultur im sächsischen Erwerbsobstbau ist der Apfel. Die Weltapfelproduktion wird weiter zunehmen. Im Gegensatz dazu bleibt der Apfelkonsum eher stabil. Dies führt in der Zukunft zu noch größerem Konkurrenzkampf auf den Absatzmärkten. Aus diesem Grund wurde im Rahmen des Projektes „Entwicklung wirtschaftlicher Anbauverfahren von Beerenobst mit Überdachung“ nach wirtschaftlichen Anbauverfahren mit anderen Obstarten zur Ergänzung der Apfelproduktion gesucht. Zu diesem Zweck erfolgte im Obstgut Jentzsch in Bosewitz die Pflanzung einer 1 ha gro-ßen Beerenobstanlage. Ziel war die Produktion von Beerenobst für die Frischmarktbelieferung mit optimaler Fruchtqualität, die Erprobung neuer Sorten, die Optimierung von Erziehung und Schnitt sowie die Prüfung der Wirtschaftlichkeit einer Überdachung unter den Anbaubedingungen in Sach-sen
FPGA-based High-Performance Collision Detection: An Enabling Technique for Image-Guided Robotic Surgery
Collision detection, which refers to the computational problem of finding the relative placement or con-figuration of two or more objects, is an essential component of many applications in computer graphics and robotics. In image-guided robotic surgery, real-time collision detection is critical for preserving healthy anatomical structures during the surgical procedure. However, the computational complexity of the problem usually results in algorithms that operate at low speed. In this paper, we present a fast and accurate algorithm for collision detection between Oriented-Bounding-Boxes (OBBs) that is suitable for real-time implementation. Our proposed Sweep and Prune algorithm can perform a preliminary filtering to reduce the number of objects that need to be tested by the classical Separating Axis Test algorithm, while the OBB pairs of interest are preserved. These OBB pairs are re-checked by the Separating Axis Test algorithm to obtain accurate overlapping status between them. To accelerate the execution, our Sweep and Prune algorithm is tailor-made for the proposed method. Meanwhile, a high performance scalable hardware architecture is proposed by analyzing the intrinsic parallelism of our algorithm, and is implemented on FPGA platform. Results show that our hardware design on the FPGA platform can achieve around 8X higher running speed than the software design on a CPU platform. As a result, the proposed algorithm can achieve a collision frame rate of 1 KHz, and fulfill the requirement for the medical surgery scenario of Robot Assisted Laparoscopy.published_or_final_versio
Test Stand For Characterization Of Microchannel Condensers Operating At Low-inlet-vapor Quality For Pumped Two-phase Cooling Loops Using Low-GWP Refrigerant
Retention of endoscopic capsules in diverticula: Literature review of a capsule endoscopy rarity
Background and study aims This review aimed to provide an updated and comprehensive review of capsule retention within diverticula, shedding light on the characteristics and management of this rare event in capsule endoscopy. Methods A systematic literature search was conducted across multiple databases. All observational studies that reported capsule retention in a diverticulum among complication and outcomes, as well as case reports and series, were included. Manual cross-checking of references was also performed. Two extractors performed abstract and full-text reviews, as well as data-extraction. Results We found 167 references from Pubmed, Embase, and Web Of Science. Sixty-five duplicates were removed and another 71 references were excluded. Crosschecking of references found additional two articles. In total, 32 articles were included, resulting in a total of 34 cases of retained capsules in diverticula. The median age was 69 and the majority of the patients were male (76.5%). The most common retention occurred in Meckel's diverticulum (32.4%) followed by Zenker's diverticulum (20.6%). Investigation of capsule retention was done with x-ray (50%) and computed tomography (CT) scan (44.1%). Seventeen cases (50%) were asymptomatic. Resolution of the retention happened with endoscopy (35.3%) and surgical management (32.4%), as well as self-resolution (20.6%). Conclusions Due to the small number of cases, diverticula are not a risk factor for incomplete capsule endoscopy examination. It affects mainly elderly, male, asymptomatic patients, and typically is diagnosed with x-rays and CT scans. The most common type is Meckel's diverticulum, and endoscopy is the primary management. Capsule endoscopy retentions are extremely rare, with only 34 cases reported since the technology's introduction. </p
Robot-assisted magnetic capsule endoscopy; navigating colorectal inclinations
Purpose: To investigate the interaction of a robot assisted magnetically driven wireless capsule endoscope (WCE) with colonic tissue, as it traverses the colorectal bends in the dorsal and ventral directions, relying only on the feedback from a 3D accelerometer. We also investigate the impact of shell geometry and water insufflation on WCE locomotion. Methods: A 3D printed incline phantom, lined with porcine colon, was used as the experimental platform, for controlled and repeatable results. The tilt angle of WCE was controlled to observe its influence on WCE locomotion. The phantom was placed underwater to observe the effects of water insufflation. The experiments were repeated using the two capsule shell geometries to observe the effect of shell geometry on WCE locomotion. Results: Friction between WCE and intestinal tissue increased when the tilt angle of the WCE was lower than the angle of the incline of the phantom. Increasing the WCE tilt angle to match the angle of the incline reduced this friction. Water insufflation and elliptical capsule shell geometry reduced the friction further. Conclusion: Tilting of the WCE equal to, or more than the angle of the incline improved the WCE locomotion. WCE locomotion was also improved by using elliptical capsule shell geometry and water insufflation. Abbreviations: CRC: colorectal cancer; GI: gastrointestinal; MRI: magnetic resonance imaging; WCE: wireless capsule endoscopeRobot-assisted magnetic capsule endoscopy; navigating colorectal inclinationspublishedVersio
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Multi-scenario Extreme Weather Simulator application to heat waves: Ko’olauloa community resilience hub
Heat waves are increasing in severity, duration, and frequency. The Multi-Scenario Extreme Weather Simulator (MEWS) models this using historical data, climate model outputs, and heat wave multipliers. In this study, MEWS is applied for planning of a community resilience hub in Hau’ula, Hawaii. The hub will have normal operations and resilience operations modes. Both these modes were modeled using EnergyPlus. The resilience operations mode includes cutting off air conditioning for many spaces to decrease power requirements during emergencies. Results were simulated for 300 future weather files generated by MEWS for 2020, 2040, 2060, and 2080. Shared socioeconomic pathways 2–4.5, 3–7.0 and 5–8.5 were used. The resilience operations mode results show two to six times increase of hours of exceedance beyond 32.2 °C from present conditions, depending on climate scenario and future year. The resulting decrease in thermal resilience enables an average decrease of energy use intensity of 26% with little sensitivity to climate change. The decreased thermal resilience predicted in the future is undesirable, but was not severe enough to require a more energy-intensive resilience mode. Instead, planning is needed to assure vulnerable individuals are given prioritized access to air-conditioned parts of the hub if worst-case heat waves occur
Optical communications through tissue
In capsule endoscopy, the wireless data transmission technologies currently employed suffer from high path loss, heavily impacting on the capsule power budget. Optical data transmission shows, in principle, scope to overcome this limitation, at least in selected tissues. Bench testing technologies, and Monte Carlo simulations on the impact of light scattering on carrier frequency, will be presented and discussed
Design and Use of Servo-Driven Actuators for Spanwise-Varying Control of a Backward-Facing Step Flow
An experimental study was conducted of a forced backward-facing step water flow, and the design of 16 actuators for creating the perturbations used to force the flow. The 16 actuators allowed for variant forcing in the spanwise direction with a resolution of 0.5 times the step height h. They are capable of producing unique perturbation waveforms of forcing velocity amplitudes 0 < u'/U∞ ≤ 2 and either single or multiple forcing Strouhal numbers in the range 0 < Sth ≤ 1.0. These forcing amplitudes are larger than ever used in any previous forced backward-facing step flow experiments. For measurement of the reattachment length in the wake of the backward-facing step, a novel hydro-tuft was designed which can indicate flow direction for local flow velocities less than 5 cm/s. A set of images taken of an array of hydro-tufts was computationally processed using a MATLAB program to calculate a time-averaged reattachment line. The effect of spanwise-invariant forcing for amplitudes 0 < u'/U∞ ≤ 2 and forcing Strouhal numbers 0 < Sth ≤ 0.5 was investigated. The results show an optimal Sth which shifts to a lower value with increasing forcing amplitude, and a non-monotonic shortening of the reattachment length. As a function of forcing amplitude, reattachment reaches a pronounced minimum at u'/U∞ ≈ 0.3 − 0.4, and then rises to a peak at u'/U∞ ≈ 0.5 − 0.6. Any further increase in forcing amplitudes up to our maximum at u'/U∞ = 2 results in more shortening. None of these behaviours have been previously noted in the literature
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