Development of a haptic feedback actuator for an endovascular interventions simulator interface

Endovascular interventions are minimally invasive surgical procedures that are performed to diagnose and treat vascular diseases using flexible instruments known as guidewire and catheter. A popular method of developing the skills required to manipulate the instruments successfully is through the use of virtual reality (VR) simulators. However, the interfaces of current VR simulators have several shortcomings and a major challenge of addressing the shortcomings is to unobtrusively access the central, co-axial guidewire for haptics. This work sets out to explore two different approaches for applying force to the concentric guidewire: direct non-contact electromagnetic force application and a custom actuator designed to be embedded within a catheter hub. An initial implementation of the hub actuator approach was able to produce a suitably strong resistance effect when the guidewire is advanced, but further work is needed to reduce the actuator size while maintaining the level of resistance

Design of a modular testing platform for the handling and study of endovascular devices

A design for a modular testing platform to objectively evaluate the behavior and characteristics of specialized endovascular instruments (guidewires/catheters) was presented and discussed. The platform comprises of an instrument driving mechanism and an interchangeable channel module depending on the parameter that is being measured. This platform could be used to study and benchmark commercial endovascular instruments. Such a guide would be useful to assist clinicians in the selection of the best tools for a given procedure and derive the behavioral model for each instrument

Preliminary characterization of corn cob ash as an alternative material for ceramic hollow fiber membrane (CHFM/CCA)

Currently, exchanging trends in the expensive usage of ceramic materials such as alumina, zirconia etc. into economical ceramic raw sources have been extensively studied over the last decade for various technological applications. Despite the fact that this ceramic compound or elements offer a great performance and stability, especially at high temperature, the basic commercial price and higher sintering temperature of this compound which is a little bit higher have hindered the used of these materials. Thus interest in fabricating of bio-ceramic membrane using corn cob ash (CCA), an agricultural by product not only offered the development of new low cost materials but also able to enhance better properties and performance. The suitability of corn cob ash as an alternative material for ceramic hollow fiber membrane fabrication (CHFM/CCA) as a main substrate was investigated via combined phase inversion and sintering technique based on several controlled operating parameters. The effects of selected bore fluid (5, 10, 15 and 20 mL/min) and different sintering temperature (800 °C, 900 °C, 1000 °C, 1100 °C) towards membrane structure and properties were observed and studied. Interestingly, characterization analysis of the SEM morphology showed that the potential of the main constituents of corn cob ash which highly consisted of silica, alumina and calcium oxide are able to improve the properties of CHFM/CCA by lowering sintering temperature (1000 °C) as compared to the standard CHFM bodies which normally has sintering temperature higher than 1200 °C. Thus, the use of corn cob ash not only able to enhance ceramic properties but also able to reduce sintering temperature. Reduction in energy consumption with slightly reduced sintering temperature also will offer a better sustainable process through recycling abundant waste materials as well as emphasis on the green resources. With that respect, the bio-material of corn cob ash is capable to replace the commercial ceramic membrane materials for membrane applications by considering the availability of this agro waste product as the main crops in most countries in the world

Characterization of a Magnetorheological Fluid Damper Applied to Semi-Active Engine Mounting System / M. Hafiz Harun...[et al.]

This study is to propose a hysteresis damper model that can be integrated with the vehicle control system. A prototype of magnetorheological for engine mounting has been designed and tested to realize the objective of this study. The experimental on the prototype of the magnetorheological damper for engine mounts has been conducted in order to investigate the hysteresis of this damper. From the experiment, the results are evaluated in terms of damping force versus piston displacement and also the damping force versus piston velocity. It is significantly shows that the proposed model satisfy the non-linear hysteresis behavior of the MR damper in the form of force-velocity and force-displacement characteristics

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Lateral suspension control of railway vehicle using semi-active magnetorheological damper

In railway vehicle technology, there are continuously increasing requirements regarding riding comfort, running safety, and speed of railway vehicles. These requirements are opposed by the fact that the condition of the tracks is getting worse and maintenance is becoming expensive. In view of this conflict, conventional suspension concepts are quickly at their limits. This paper investigates the performance of semi-active control of lateral suspension system namely body-based skyhook and bogie-based skyhook for the purpose of attenuating the effects of track irregularities to the body lateral displacement, body roll angle and unwanted yaw responses of railway vehicle. The controller is optimized on 17 degrees of freedom (DoF) railway vehicle dynamics model and showing better dynamics performance than its counterparts

A study of haptic effects in endovascular interventions

During an endovascular intervention, interventionists rely on their sense of touch to perform the procedures correctly. However, there is a paucity of literature regarding the intricacies of the haptic component of the interventions. The objectives of this study were to capture the types and magnitude of haptic effects during real-life interventions from subject matter experts. The study consisted of an online questionnaire and a force measurement experiment to help determine the force types and magnitude. Participants were interventionists with significant procedural experience. The data recorded from the online questionnaire and the experimental study was analysed using descriptive statistics and hypothesis testing techniques. Participants identified four different types of haptic effects: translational resistance, rotational resistance, bump effect and heart beat pressure effect. The characteristics of each effect, such as factor of occurrence and direction, were established and they were compared against each other. Translational resistance was recognised as the strongest, followed by rotational resistance, bump effect and heart beat pressure. In the force measurement experiment, the forces involved in the generation of translational resistance were found to be in the range 0-0.5 N in healthy vessels, 0.5 – 1.5 N in tortuous/narrowed vessels and 1.5 – 2 N in calcified or occluded vessels. Measurements for the bump effect provided less conclusive results due to its subtle nature, although current findings suggest forces between 0.1 – 0.2 N. Overall, the study was successful in expanding current knowledge of haptic effects in endovascular interventions, highlighting the existence of a variety of effects and their characteristics

Study The Potential Application Of Smart Fluid Material And Force Tracking Control Of Magnetorheological Damper

The aim of this paper is to study the potential application of magnetorhelogical (MR)fluid as a smart material used in semi-active damper of a vehicle suspension system.An MR damper was designed and fabricated and tested in the laboratory using damper test machine.The non-linear behaviour of the MR damper is modelled using third order polynomial model based on experimental data.Force tracking control is carried out in order to track the ability of the MR damper to produce force as close as possible with the desired force. Continuous state control is chosen for the inner loop controller of the MR damper.The performance of the proposed controller as a force-tracking controller is compared with the desired force produced by vehicle system.The results of the study shows that the proposed controller is able to track the desired force successfully