In vitro virtual reality: an anatomically explicit musculoskeletal simulation powered by in vitro muscle using closed-loop tissue–software interaction

Virtual reality involves the creation of multisensory experience of an environment (its space and events) through artificial, electronic means; but that environment incorporates a sufficient number of features of the non-artificial world that it is experienced as “reality.” The cognitive issues of virtual reality are those that are involved in knowing and understanding about the virtual environment (cognitive: to perceive and to know). The knowledge we are concerned with in this chapter is both short term (Where am I in the environment? What do I see? Where do I go and how do I get there?), and long term (What can and do I learn about the environment as I see and explore it?). Given the recent interest in virtual reality as a concept (Rheingold, 1991; Wexelblat, 1993; Durlach and Mavor, 1994), it is important to consider that virtual reality is not, in fact, a unified thing, but can be broken down into a set of five features, any one of which can be present or absent to create a greater sense of reality. These features consist of the following five points. 1. Three-dimensional (perspective and/or stereoscopic) viewing vs. two-dimensional planar viewing. (Sedgwick, 1986; Wickens et al., 1989). Thus, the geography student who views a 3D representation of the environment has a more realistic view than one who views a 2D contour map. 2. Dynamic vs. static display. A video or movie is more real than a series of static images of the same material. 3. Closed-loop (interactive or learner-centered) vs. open-loop interaction. A more realistic closed-loop mode is one in which the learner has control over what aspect of the learning “world” is viewed or visited. That is, the learner is an active navigator as well as an observer. 4. Inside-out (ego-referenced) vs. outside-in (world-referenced) frame-of-reference. The more realistic inside-out frame-of-reference is one in which the image of the world on the display is viewed from the perspective of the point of ego-reference of the user (that point which is being manipulated by the control). This is often characterized as the property of “immersion.” Thus, the explorer of a virtual undersea environment will view that world from a perspective akin to that of a camera placed on the explorer’s head;

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In vitro evaluation of delays in the adjustment of the fraction of inspired oxygen during CPAP: effect of flow and volume

Archives of Disease in Childhood - Fetal and Neonatal Edition ◽

10.1136/archdischild-2020-319058 ◽

2020 ◽

pp. fetalneonatal-2020-319058

Author(s):

Christoph E. Schwarz ◽

Gordon Lightbody ◽

Ingo Müller-Hansen ◽

Jörg Arand ◽

Christian F. Poets ◽

...

Keyword(s):

Gas Flow ◽

Closed Loop ◽

Volume Flow ◽

Target Range ◽

Equilibration Time ◽

Ventilator Circuit ◽

Fraction Of Inspired Oxygen ◽

Inspired Oxygen

BackgroundAdjusting the fraction of inspired oxygen (FiO2) delivered to preterm infants to keep their oxygen saturation within target range remains challenging. Closed-loop automated FiO2 control increases the time infants spend within the assigned target range. The delay with which FiO2 adjustments at the ventilator result in a change in the inspired gas limits the performance of both manual and automated controls.ObjectiveTo evaluate the equilibration time (Teq) between FiO2 adjustments and changes in FiO2 reaching the patient.MethodsIn vitro determination of the delay in FiO2 adjustments at the ventilator at 5 and 8 L/min of gas flow and two different humidifier/ventilator circuit volumes (840 and 432 mL).ResultsTeq values were 31, 23, 20 and 17 s for the volume–flow combinations 840 mL+5 L/min, 840 mL+8 L/min, 432 mL+5 L/min and 432 mL+8 L/min, respectively.ConclusionThe identified delay seems clinically relevant and should be taken into account during manual and automatic control of FiO2.

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3D Encapsulation Made Easy: A Coaxial-Flow Circuit for the Fabrication of Hydrogel Microfibers Patches

Bioengineering ◽

10.3390/bioengineering6020030 ◽

2019 ◽

Vol 6 (2) ◽

pp. 30 ◽

Cited By ~ 3

Author(s):

Chiara Campiglio ◽

Francesca Ceriani ◽

Lorenza Draghi

Keyword(s):

Hyaluronic Acid ◽

Regenerative Medicine ◽

Closed Loop ◽

Fiber Diameter ◽

Cross Linking ◽

Scaffold Fabrication ◽

Cell Culturing ◽

Viable Cells ◽

Flow Circuit

To fully exploit the potential of hydrogel micro-fibers in the design of regenerative medicinal materials, we designed a simple, easy to replicate system for cell embedding in degradable fibrous scaffolds, and validated its effectiveness using alginate-based materials. For scaffold fabrication, cells are suspended in a hydrogel-precursor and injected in a closed-loop circuit, where a pump circulates the ionic cross-linking solution. The flow of the cross-linking solution stretches and solidifies a continuous micro-scaled, cell-loaded hydrogel fiber that whips, bends, and spontaneously assembles in a self-standing, spaghetti-like patch. After investigation and tuning of process- and solution-related parameters, homogeneous microfibers with controlled diameters and consistent scaffolds were obtained from different alginate concentrations and blends with biologically favorable macromolecules (i.e., gelatin or hyaluronic acid). Despite its simplicity, this coaxial-flow encapsulation system allows for the rapid and effortless fabrication of thick, well-defined scaffolds, with viable cells being homogeneously distributed within the fibers. The reduced fiber diameter and the inherent macro-porous structure that is created from the random winding of fibers can sustain mass transport, and support encapsulated cell survival. As different materials and formulations can be processed to easily create homogeneously cell-populated structures, this system appears as a valuable platform, not only for regenerative medicine, but also, more in general, for 3D cell culturing in vitro.

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Neurophilosophical and Ethical Aspects of Virtual Reality Therapy in Neurology and Psychiatry

Cambridge Quarterly of Healthcare Ethics ◽

10.1017/s0963180118000129 ◽

2018 ◽

Vol 27 (4) ◽

pp. 610-627 ◽

Cited By ~ 6

Author(s):

PHILIPP KELLMEYER

Keyword(s):

Virtual Reality ◽

Closed Loop ◽

Reality Therapy ◽

Ethical Challenges ◽

Ethical Aspects ◽

Consumer Market ◽

Ethical Implications ◽

The Past ◽

Core Concepts ◽

Legal Accountability

Abstract:Highly immersive virtual reality (VR) systems have been introduced into the consumer market in recent years. The improved technological capabilities of these systems as well as the combination with biometric sensors, for example electroencephalography (EEG), in a closed-loop hybrid VR-EEG, opens up a range of new potential medical applications. This article first provides an overview of the past and current clinical applications of VR systems in neurology and psychiatry and introduces core concepts in neurophilosophy and VR research (such as agency, trust, presence, and others). Then, important adverse effects of highly immersive VR simulations and the ethical implications of standalone and hybrid VR systems for therapy in neurology and psychiatry are highlighted. These new forms of VR-based therapy may strengthen patients in exercising their autonomy. At the same time, however, these emerging systems present ethical challenges, for example in terms of moral and legal accountability in interactions involving “intelligent” hybrid VR systems. A user-centered approach that is informed by the target patients’ needs and capabilities could help to build beneficial systems for VR therapy.

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