Video-based assistance system for training in minimally invasive surgery

In this paper, the development of an assisting system for laparoscopic surgical training is presented. With this system, we expect to facilitate the training process at the first stages of training in laparoscopic surgery and to contribute to an objective evaluation of surgical skills. To achieve this, we propose the insertion of multimedia contents and outlines of work adapted to the level of experience of trainees and the detection of the movements of the laparoscopic instrument into the monitored image. A module to track the instrument is implemented focusing on the tip of the laparoscopic tool. This tracking method does not need the presence of artificial marks or special colours to distinguish the instruments. Similarly, the system has another method based on visual tracking to localize support multimedia content in a stable position of the field of vision. Therefore, this position of the support content is adapted to the movements of the camera or the working area. Experimental results are presented to show the feasibility of the proposed system for assisting in laparoscopic surgical training

Laparoscopic image analysis for automatic tracking of surgical tools

Laparoscopy is a surgical technique nowadays embedded in the clinical routine. Recent researches have been focused on analysing video information captured by the endoscope for extracting cues useful for surgeons, such as depth information. In particular, the 3D pose estimation of the surgical tools presents three important added values: (1) to extract objective parameters for the surgical training stage, (2) to develop an image-guided surgery based on the knowledge of the surgery tools localization, (3) to design new roboticsystems for an automatic laparoscope positioning, according to the visual feedback. Tool’s shape and orientation in the image is the key to get its 3D position. This work presents an image analysis for automatic laparoscopic tool’s detection along the recorded video without extra tool markers, using an edges detection strategy. Also, this analysis includes a previous stage of barrel distortion correction for videoendoscopic image

Caveolin-1 Modulates Mechanotransduction Responses to Substrate Stiffness through Actin-Dependent Control of YAP

The transcriptional regulator YAP orchestrates many cellular functions, including tissue homeostasis, organ growth control, and tumorigenesis. Mechanical stimuli are a key input to YAP activity, but the mechanisms controlling this regulation remain largely uncharacterized. We show that CAV1 positively modulates the YAP mechanoresponse to substrate stiffness through actin-cytoskeleton-dependent and Hippo-kinase-independent mechanisms. RHO activity is necessary, but not sufficient, for CAV1-dependent mechanoregulation of YAP activity. Systematic quantitative interactomic studies and image-based small interfering RNA (siRNA) screens provide evidence that this actin-dependent regulation is determined by YAP interaction with the 14-3-3 protein YWHAH. Constitutive YAP activation rescued phenotypes associated with CAV1 loss, including defective extracellular matrix (ECM) remodeling. CAV1-mediated control of YAP activity was validated in vivo in a model of pancreatitis-driven acinar-to-ductal metaplasia. We propose that this CAV1-YAP mechanotransduction system controls a significant share of cell programs linked to these two pivotal regulators, with potentially broad physiological and pathological implications. Moreno-Vicente et al. report that CAV1, a key component of PM mechanosensing caveolae, mediates adaptation to ECM rigidity by modulating YAP activity through the control of actin dynamics and phosphorylation-dependent interaction of YAP with the 14-3-3-domain protein YWHAH. Cav1-dependent YAP regulation drives two pathophysiological processes: ECM remodeling and pancreatic ADM. © 2018 The Author

Experimental response of agglomerated cork under multi-impact loads

In contrast to other cellular materials, which deform by crushing under impact and develop permanent deformation, agglomerated cork has a viscoelastic response and is environmentally friendly; therefore, it could be a good alternative to be used in engineering applications subjected to more than one impact, and thus further understanding of the energy-absorption capabilities of this material under multi-impact conditions is needed. In this work the multi-impact behaviour of agglomerated cork was studied experimentally by performing several consecutive impacts in a drop-weight tower on specimens of different thickness and at two impact energy levels. The maximum contact force, maximum strain, and the absorbed energy were evaluated in each test. The results show the great capability of agglomerated cork to continue absorbing energy after several consecutive impacts.Publicad

Application of model predictive control to parabolic trough thermal solar plants

[EN] One of the main methods to improve the efficiency in the use of solar energy is the application of advanced control techniques.This work develops a state of the art of predictive control applications to small and large scale solar trough plants. Two realapplications are presented. The first one is designed to the old ACUREX experimental plant at the Plataforma solar de Almer ??a(PSA). The second one is the design of a model predictive controller for large scale commercial CCP plants that is installed in 13Spanish plants as well as in the Mojave solar trough plants in California (USA). Finally, two real results obtained at the MojaveBeta plant are presented showing the adequate performance of the controller.[ES] Uno de los principales métodos para mejorar la eficiencia en el uso y aprovechamiento de la energía solar es la aplicación de técnicas avanzadas de control. En este trabajo se presenta un estado del arte de las aplicaciones de control predictivo en plantassolares de pequeña y gran escala. Se presentan además dos aplicaciones reales: una que se diseño para la planta experimental ACUREX en la Plataforma solar de Almería (PSA). El controlador fue probado en el campo real con buen desempeño. La otra aplicación describe el diseño de un controlador predictivo para plantas comerciales de colectores cilindro parabólicos (CCP) que está instalado en 13 plantas Españolas así como en las plantas de Mojave en California (USA). Se muestran dos resultados reales obtenidos en la planta Mojave Beta con el controlador propuesto.Los autores quieren agradecer a Atlantica Sustainable Infrastructure por financiar y participar en la realización de este proyecto. Los autores agradecen tambien al European Research Council por financiar el trabajo mediante la Advanced Grant OCONTSOLAR (Project ID: 789051).Gallego Len, AJ.; Sánchez Del Pozo, AJ.; Camacho, EF. (2022). Aplicaciones de control predictivo en plantas solares CCP. Revista Iberoamericana de Automática e Informática industrial. 19(3):309-317. https://doi.org/10.4995/riai.2022.16664OJS30931719

Comparative study of two laparoscopic instrument tracker designs for motion analysis and image-guided surgery: a technical evaluation

Laparoscopic instrument tracking systems are a key element in image-guided interventions, which requires high accuracy to be used in a real surgical scenario. In addition, these systems are a suitable option for objective assessment of laparoscopic technical skills based on instrument motion analysis. This study presents a new approach that improves the accuracy of a previously presented system, which applies an optical pose tracking system to laparoscopic practice. A design enhancement of the artificial markers placed on the laparoscopic instrument as well as an improvement of the calibration process are presented as a means to achieve more accurate results. A technical evaluation has been performed in order to compare the accuracy between the previous design and the new approach. Results show a remarkable improvement in the fluctuation error throughout the measurement platform. Moreover, the accumulated distance error and the inclination error have been improved. The tilt range covered by the system is the same for both approaches, from 90º to 7.5º. The relative position error is better for the new approach mainly at close distances to the camera syste

Sistema de seguimiento del instrumental laparoscópico basado en marcas artificiales: pruebas iniciales

Sistema de seguimiento del instrumental laparoscópico basado en marcas artificiales: pruebas iniciale

Technical evaluation of a third generation optical pose tracker for motion analysis and image-guided surgery

Laparoscopic instrument tracking systems are an essential component in image-guided interventions and offer new possibilities to improve and automate objective assessment methods of surgical skills. In this study we present our system design to apply a third generation optical pose tracker (Micron- Tracker®) to laparoscopic practice. A technical evaluation of this design is performed in order to analyze its accuracy in computing the laparoscopic instrument tip position. Results show a stable fluctuation error over the entire analyzed workspace. The relative position errors are 1.776±1.675 mm, 1.817±1.762 mm, 1.854±1.740 mm, 2.455±2.164 mm, 2.545±2.496 mm, 2.764±2.342 mm, 2.512±2.493 mm for distances of 50, 100, 150, 200, 250, 300, and 350 mm, respectively. The accumulated distance error increases with the measured distance. The instrument inclination covered by the system is high, from 90 to 7.5 degrees. The system reports a low positional accuracy for the instrument tip

Evolution of occupational asthma: Does cessation of exposure really improve prognosis?

SummaryAimTo assess the evolution of occupational asthma (OA) depending on whether the patient avoids or continues with exposure to the offending agent.MethodsStudy in patients diagnosed with OA using a specific inhalation challenge. Patients underwent the following examinations on the same day: clinical interview, physical examination, forced spirometry, methacholine test and determination of total IgE. Clinical improvement, deterioration or no change were defined according to the changes seen on the GINA severity scale at the time of diagnosis.ResultsOf the 73 patients finally included, 55 had totally ended exposure and 18 continued to be exposed at work. Clinical improvement was observed in 47% of those who had terminated exposure and in 22% of those who remained exposed; clinical deterioration was observed in 14% and 17% respectively (p = 0.805). Logistical regression analysis, including the type of agent and the persistence or avoidance of exposure among the variables, did not show any predictive factors of clinical evolution. Similarly, the changes in FEV1 and in bronchial hyperresponsiveness were not associated with the avoidance or continuation of exposure to the causative agent.ConclusionsAvoiding exposure to the causative agent in patients with OA does not seem to improve prognosis in this disease. Despite these findings, there is insufficient evidence to recommend a change in current management guidelines

Evaluation of Mechanical Characteristics of Cement Mortar with Fine Recycled Concrete Aggregates (FRCA)

[EN] One of the growing demands in concrete manufacture is the availability of natural fine aggregates, which account for 35% to 45% of the total concrete. An alternative method of disposal of fine recycled concrete aggregates (FRCA) generated from demolition and construction waste (C&DW) is their usage in mortar and the development of recycled mortar. The main aim of this research work is to evaluate the viability of incorporating FRCA from urban C&DW for the manufacture of cement-based mortars. Simple processing techniques like washing and sieving are adopted to improve the FRCA quality. Physical and chemical characterization of ingredients is carried out. In total four mixes of 1:3 (cement: sand) mortar with partial replacement of normalized sand with FRCA (0%, 25%, 50%, and 100%) are evaluated for mechanical properties. Water to cement ratio for all four mortar mixes are determined by fixed consistency. Mechanical and physical properties like density, compressive strength, and flexural strength are studied for various curing periods, and the result is that the optimum usage of FRCA is 25% based on a 90-day curing period.SIReutiliza S.L. for offering the recycled and natural aggregate used in this study free of cost. Eduardo Torroja Institute for Construction Science and FCT for financial support