Introducing the keyconcept approach to the analysis of language: the case of regulation in COVID-19 diaries.

Using the Mass Observation corpus of 12th of May Diaries, we investigate concepts that are characteristic of the first coronavirus lockdown in the UK. More specifically, we extract and analyse concepts which are distinctive of the discourses produced in May 2020 in relation to concepts used in the 10 previous years, 2010-2019. In the current paper we focus on the concept of regulation, which we identify through a novel approach to querying semantic content in large datasets. Typically, linguists look at keywords to understand differences between two datasets. We demonstrate that taking the perspective of a keyconcept rather than the keyword in linguistic analysis is a beneficial way of identifying trends in broader patterns of thoughts and behaviours which reflect lived-experiences that are particularly prominent of a given dataset, which, in this current paper, is the COVID-19 era dataset. In order to contextualise the keyconcept analysis, we investigate the discourses surrounding the concept of regulation. We find that diarists communicate collective experience of limited individual agency, surrounded by feelings of fear and gratitude. Diarists' reporting on events is often fragmented, focused on new information, and firmly placed in a temporal frame.

A Systematic Review on Methods and Tools for the In Situ Fenestration of Aortic Stent-Graft.

In situ fenestration of stent-graft represents a potential option for the treatment of aortic diseases in patients unsuitable for standard endovascular repair. The best fenestration strategy to restore perfusion of collateral vessels after their coverage by an endograft depends mainly on the anatomical area. Several tools are employed as fenestration devices, including needles, radiofrequency probes, and laser systems, used in conjunction with other instrumentation to provide enough support and stability during the procedure. In this systematic review, the approaches to reach the correct fenestration site both in human, animal, and in in vitro environments are described and discussed, highlighting advantages and limitations. Both commercial and dedicated solutions for the intraoperative modification of the fabric material are reported as well. The clinical interest in this procedure has so far encouraged researchers to develop and refine both methods and tools to solve the current limitations of this technique, intending to extend the indications for endovascular treatment to a broader range of patients.

Bioengineering, augmented reality, and robotic surgery in vascular surgery: A literature review.

Biomedical engineering integrates a variety of applied sciences with life sciences to improve human health and reduce the invasiveness of surgical procedures. Technological advances, achieved through biomedical engineering, have contributed to significant improvements in the field of vascular and endovascular surgery. This paper aims to review the most cutting-edge technologies of the last decade involving the use of augmented reality devices and robotic systems in vascular surgery, highlighting benefits and limitations. Accordingly, two distinct literature surveys were conducted through the PubMed database: the first review provides a comprehensive assessment of augmented reality technologies, including the different techniques available for the visualization of virtual content (11 papers revised); the second review collects studies with bioengineering content that highlight the research trend in robotic vascular surgery, excluding works focused only on the clinical use of commercially available robotic systems (15 papers revised). Technological flow is constant and further advances in imaging techniques and hardware components will inevitably bring new tools for a clinical translation of innovative therapeutic strategies in vascular surgery.

Hybrid Simulation and Planning Platform for Cryosurgery with Microsoft HoloLens.

Cryosurgery is a technique of growing popularity involving tissue ablation under controlled freezing. Technological advancement of devices along with surgical technique improvements have turned cryosurgery from an experimental to an established option for treating several diseases. However, cryosurgery is still limited by inaccurate planning based primarily on 2D visualization of the patient's preoperative images. Several works have been aimed at modelling cryoablation through heat transfer simulations; however, most software applications do not meet some key requirements for clinical routine use, such as high computational speed and user-friendliness. This work aims to develop an intuitive platform for anatomical understanding and pre-operative planning by integrating the information content of radiological images and cryoprobe specifications either in a 3D virtual environment (desktop application) or in a hybrid simulator, which exploits the potential of the 3D printing and augmented reality functionalities of Microsoft HoloLens. The proposed platform was preliminarily validated for the retrospective planning/simulation of two surgical cases. Results suggest that the platform is easy and quick to learn and could be used in clinical practice to improve anatomical understanding, to make surgical planning easier than the traditional method, and to strengthen the memorization of surgical planning.

Definition of Proficiency Level by a Virtual Simulator as a First Step Toward a Curriculum on Fundamental Skills for Endovascular Aneurysm Repair (EVAR).

OBJECTIVE: At present, there is no proficiency-based curriculum for endovascular treatment of aortic aneurysm repair (EVAR) using virtual reality (VR) surgical simulators, whereas such curricula are available for the treatment of iliac and/or superficial femoral artery disease. The purpose of this work was to compute proficiency, defined by a benchmark level determined by the performance of experts, using a commercial VR simulator as a first step of a curriculum on EVAR. MATERIALS AND METHODS: Expert endovascular surgeons (with more than 150 EVAR cases as first operators) from 12 major Italian centers completed three cases of EVAR of increasing difficulty level 3 times each, using the Angio Mentor simulator (by Simbionix) and Gore devices. Proficiency level was based on performance of expert surgeons, as assessed by metrics from a VR simulator. RESULTS: The participating surgeons had a median of 20 years of experience and executed a median of 440 EVAR. For the 3 simulated cases, the following proficiency values were respectively obtained: total procedure time: 22 minutes 32 seconds, 23 minutes 05 seconds, and 20 minutes 32 seconds; total amount of contrast injected: 85.16 mL, 89.97 mL, and 98.01 mL total fluoroscopy time: 10 minutes 39 seconds, 12 minutes 22 seconds, and 10 minutes 17 seconds; time to contralateral gate cannulation: 5 minutes 51 seconds, 7 minutes 09 seconds, and 3 minutes 32 seconds. CONCLUSIONS: We computed proficiency levels for 3 simulated cases of EVAR using a VR simulator. Our next step is to determine whether surgical residents can reach this level. Translational research will then be required to assess the impact of such training on real patients.

A simple, realistic walled phantom for intravascular and intracardiac applications.

PURPOSE: This work aims to develop a simple, anatomically and haptically realistic vascular phantom, compatible with intravascular and intracardiac ultrasound. The low-cost, dual-layered phantom bridges the gap between traditional wall-only and wall-less phantoms by showing both the vessel wall and surrounding tissue in ultrasound imaging. This phantom can better assist clinical tool training, testing of intravascular devices, blood flow studies, and validation of algorithms for intravascular and intracardiac surgical systems. METHODS: Polyvinyl alcohol cryogel (PVA-c) incorporating a scattering agent was used to obtain vessel and tissue-mimicking materials. Our specific design targeted the inferior vena cava and renal bifurcations which were modelled using CAD software. A custom mould and container were 3D-printed for shaping the desired vessel wall. Three phantoms were prepared by varying both the concentrations of scattering agent as well as the number of freeze-thaw cycles to which the phantom layers were subjected during the manufacturing process. Each phantom was evaluated using ultrasound imaging using the Foresight™ ICE probe. Geometrical validation was provided by comparing CAD design to a CT scan of the phantom. RESULTS: The desired vascular phantom was constructed using 2.5% and 0.05% scattering agent concentration in the vessel and tissue-mimicking layers, respectively. Imaging of the three phantoms showed that increasing the number of freeze-thaw cycles did not significantly enhance the image contrast. Comparison of the US images with their CT equivalents resulted in an average error of 0.9[Formula: see text] for the lumen diameter. CONCLUSION: The phantom is anatomically realistic when imaged with intracardiac ultrasound and provides a smooth lumen for the ultrasound probe and catheter to manoeuvre. The vascular phantom enables validation of intravascular and intracardiac image guidance systems. The simple construction technique also provides a workflow for designing complex, multi-layered arterial phantoms.

Perceptual Limits of Optical See-Through Visors for Augmented Reality Guidance of Manual Tasks.

OBJECTIVE: The focal length of available optical see-through (OST) head-mounted displays (HMDs) is at least 2 m; therefore, during manual tasks, the user eye cannot keep in focus both the virtual and real content at the same time. Another perceptual limitation is related to the vergence-accommodation conflict, the latter being present in binocular vision only. This paper investigates the effect of incorrect focus cues on the user performance, visual comfort, and workload during the execution of augmented reality (AR)-guided manual task with one of the most advanced OST HMD, the Microsoft HoloLens. METHODS: An experimental study was designed to investigate the performance of 20 subjects in a connect-the-dots task, with and without the use of AR. The following tests were planned: AR-guided monocular and binocular, and naked-eye monocular and binocular. Each trial was analyzed to evaluate the accuracy in connecting dots. NASA Task Load Index and Likert questionnaires were used to assess the workload and the visual comfort. RESULTS: No statistically significant differences were found in the workload, and in the perceived comfort between the AR-guided binocular and monocular test. User performances were significantly better during the naked eye tests. No statistically significant differences in performances were found in the monocular and binocular tests. The maximum error in AR tests was 5.9 mm. CONCLUSION: Even if there is a growing interest in using commercial OST HMD, for guiding high-precision manual tasks, attention should be paid to the limitations of the available technology not designed for the peripersonal space.

In situ diode laser fenestration: An ex-vivo evaluation of irradiation effects on human aortic tissue.

The in situ laser fenestration is an interesting option for the endovascular treatment of short-necked aneurysms with an intraoperative modification of a standard endograft. According to literature evidence, diode laser emitting in the near-infrared wavelength (810 nm) can be successfully used to fenestrate the endograft fabric. This paper describes a three-dimensional navigation system for the accurate targeting of the fenestration site, then reports results of an ex vivo study to assess whether the laser operative conditions, which ensure the fabric fenestration, are harmless for the biological tissue surrounding the endoprosthesis. Two hundred twenty-five samples of human aorta, including healthy specimens and abdominal aortic aneurysm samples, were irradiated ex vivo using a 810 nm diode laser. Energy and pulse duration were varied. Irradiated tissues were fixed in formaldehyde, sectioned and subjected to histological examination. Only 7.5% of the irradiated samples exhibited a thermal damage, which was always confined to the contact point between the laser fiber tip and the aortic wall. These experiments suggest that the diode laser can be safely used for the proposed surgical application.

A tele-ultrasonographic platform to collect specialist second opinion in less specialized hospitals.

In non-urban scenarios: rural areas or small cities, there is often a limited access to specialistic healthcare due to the inherent challenges associated with recruitment, retention, and access to healthcare professionals. Telemedicine is an economical and effective way to address this problem. In this research, we developed a framework for real-time communication during ultrasound examination that combines interaction via standard video conference protocols and basic AR functionalities (commercial) and a custom-developed application. The tele-ultrasonographic platform has been installed in a rural hospital in the Tuscan Apennines, and was tested on 12 patients. The study explores the utility of the system from the local and remote clinician perspectives. The results obtained provide valuable insight: the platform and the telemedicine paradigm can reduce the costs related to the necessity to move critical patients when there is a need for a specialist second opinion. Moreover, the possibility of having an expert guiding and commenting on the fly the diagnostic examination has also a didactic power, and thus allows the local less specialized clinicians to grow in competencies over time.

Design of a sensorized guiding catheter for in situ laser fenestration of endovascular stent.

PURPOSE: The in situ fenestration of a standard endograft is currently limited by difficulties in targeting the fenestration site under fluoroscopic control and by the lack of a safe method to perforate the graft. Evidence in the literature suggests the use of a 3 D electromagnetic navigator to accurately guide the endovascular instruments to the target and a laser to selectively perforate the graft. The aim of this work is to provide design guidelines to develop a sensorized catheter to guide the laser tool to the fenestration site and conduct preliminary testing of the feasibility of the proposed solution. Matherials and methods: Different catheter designs were delineated starting from engineering considerations, then prototypes were preliminarily tested to collect surgeon opinions and to steer the design process toward the preferred solution reported by the user. Finally, mechanical simulations were performed with CathCAD, a design software system for the development of composite tubing for endovascular catheters. RESULTS: Based on surgeon feedback, a 9-French steerable catheter with a stabilization system was designed. CathCAD simulations allowed us to define the construction parameters (e.g., materials and geometric constrains) for the fabrication of composite tubes with mechanical properties (flexural, axial, and torsional rigidities) compatible with target values in the literature for guiding catheters. CONCLUSION: The presented results preliminarily demonstrate the clinical reasonability and feasibility of the designed tool in terms of mechanical properties. Further mechanical tests and extensive in vitro clinical trials are required prior to animal testing.