Origami-Based Haptic Syringe for Local Anesthesia Simulator.

Although medical simulators have benefited from the use of haptics and virtual reality (VR) for decades, the former has become the bottleneck in producing a low-cost, compact, and accurate training experience. This is particularly the case for the inferior alveolar nerve block (IANB) procedure in dentistry, which is one of the most difficult motor skills to acquire. As existing works are still oversimplified or overcomplicated for practical deployment, we introduce an origami-based haptic syringe interface for IANB local anesthesia training. By harnessing the versatile mechanical tunability of the Kresling origami pattern, our interface simulated the tactile experience of the plunger while injecting the anesthetic solution. We present the design, development, and characterization process, as well as a preliminary usability study. The force profile generated by the syringe interface is perceptually similar with that of the Carpule syringe. The usability study suggests that the haptic syringe significantly improves the IANB training simulation and its potential to be utilized in several other medical training/simulation applications.

AI-based shape optimization of galloping micro-power generators: exploring the benefits of curved surfaces.

The advent of flow micro-power generation has resparked the interest in researching the galloping instability with the objective of determining the shape of the bluff body that is most prone to galloping. Such shape, which is sought to maximize the efficacy of galloping micro-power generators (GMPGs), must possess a very low cut-in flow speed while achieving large-amplitude steady-state oscillations beyond it. Additionally, since GMPGs can operate in environments with fluctuating flow conditions, the optimal shape must also have a very short rise time to its steady-state amplitude. In this work, we utilize computational fluid dynamics in conjunction with machine learning to optimize the shape of the bluff body of GMPGs for both steady-state and transient performance. We investigate a continuum shape description which encapsulates most of the cases studied earlier in the literature. The continuum has a straight frontal and dorsal faces with varying lengths, and side faces described by surfaces of different curvatures. The optimization study reveals that a curved-trapezoidal bluff body with the highest side surface curvature and frontal-to-dorsal ratio is the perfect shape for steady flow conditions. On the other hand, a square profile with the highest side surface curvature is the ideal choice for highly-fluctuating flow conditions because of its shortest rise time. The theoretical findings are replicated experimentally using wind tunnel tests.

Perception, performance, and detectability of conversational artificial intelligence across 32 university courses.

The emergence of large language models has led to the development of powerful tools such as ChatGPT that can produce text indistinguishable from human-generated work. With the increasing accessibility of such technology, students across the globe may utilize it to help with their school work-a possibility that has sparked ample discussion on the integrity of student evaluation processes in the age of artificial intelligence (AI). To date, it is unclear how such tools perform compared to students on university-level courses across various disciplines. Further, students' perspectives regarding the use of such tools in school work, and educators' perspectives on treating their use as plagiarism, remain unknown. Here, we compare the performance of the state-of-the-art tool, ChatGPT, against that of students on 32 university-level courses. We also assess the degree to which its use can be detected by two classifiers designed specifically for this purpose. Additionally, we conduct a global survey across five countries, as well as a more in-depth survey at the authors' institution, to discern students' and educators' perceptions of ChatGPT's use in school work. We find that ChatGPT's performance is comparable, if not superior, to that of students in a multitude of courses. Moreover, current AI-text classifiers cannot reliably detect ChatGPT's use in school work, due to both their propensity to classify human-written answers as AI-generated, as well as the relative ease with which AI-generated text can be edited to evade detection. Finally, there seems to be an emerging consensus among students to use the tool, and among educators to treat its use as plagiarism. Our findings offer insights that could guide policy discussions addressing the integration of artificial intelligence into educational frameworks.

Elastic Organic Crystals as Bioinspired Hair-Like Sensors.

One of the typical haptic elements are natural hairy structures that animals and plants rely on for feedback. Although these hair sensors are an admirable inspiration, the development of active flow sensing components having low elastic moduli and high aspect ratios remains a challenge. Here, we report a new sensing approach based on a flexible, thin and optically transmissive organic crystal of high aspect ratio, which is stamped with fluorescent dye for tracking. When subjected to gas flow and exposed to laser, the crystal bends due to exerted pressure and acts as an optical flow (hair) sensor with low detection limit (≈1.578 m s-1 ) and fast response time (≈2.70 s). The air-flow-induced crystal deformation and flow dynamics response are modelled by finite element analysis. Due to having a simple design and being lightweight and mechanically robust this prototypical crystal hair-like sensor opens prospects for a new class of sensing devices ranging from wearable electronics to aeronautics.

3D microenvironment attenuates simulated microgravity-mediated changes in T cell transcriptome.

Human space travel and exploration are of interest to both the industrial and scientific community. However, there are many adverse effects of spaceflight on human physiology. In particular, there is a lack of understanding of the extent to which microgravity affects the immune system. T cells, key players of the adaptive immune system and long-term immunity, are present not only in blood circulation but also reside within the tissue. As of yet, studies investigating the effects of microgravity on T cells are limited to peripheral blood or traditional 2D cell culture that recapitulates circulating blood. To better mimic interstitial tissue, 3D cell culture has been well established for physiologically and pathologically relevant models. In this work, we utilize 2D cell culture and 3D collagen matrices to gain an understanding of how simulated microgravity, using a random positioning machine, affects both circulating and tissue-resident T cells. T cells were studied in both resting and activated stages. We found that 3D cell culture attenuates the effects of simulated microgravity on the T cells transcriptome and nuclear irregularities compared to 2D cell culture. Interestingly, simulated microgravity appears to have less effect on activated T cells compared to those in the resting stage. Overall, our work provides novel insights into the effects of simulated microgravity on circulating and tissue-resident T cells which could provide benefits for the health of space travellers.

Suppression of galloping oscillations by injecting a high-frequency excitation.

Galloping is an aeroelastic instability which incites oscillatory motion of elastic structures when subjected to an incident flow. Because galloping is often detrimental to the integrity of the structure, many research studies have focused on investigating methodologies to suppress these oscillations. These include using passive energy sinks, altering the surface characteristics of the structure, actively changing the shape of the boundary layer through momentum injection and using feedback control algorithms. In this paper, we demonstrate that the critical flow speed at which galloping is activated can be substantially increased by subjecting the galloping structure to a high-frequency non-resonant base excitation. The average effect of the high-frequency excitation is to produce additional linear damping in the slow response which serves to suppress the galloping instability. We study this approach theoretically and demonstrate its effectiveness using experimental tests performed on a galloping cantilevered structure. It is demonstrated that the galloping speed can be tripled in some experimental cases. This article is part of the theme issue 'Vibrational and stochastic resonance in driven nonlinear systems (part 2)'.

Equilibria and bifurcations of a foldable paper-based spring inspired by Kresling-pattern origami.

Origami-inspired design has recently emerged as a major thrust area of research in the fields of science and engineering. One such design utilizes Kresling-pattern origami to construct nonlinear springs that can act as mechanical bit memory switches, wave guides, fluidic muscles, and vibration isolators. The main objective of this work is to characterize the static equilibria of such springs, their stability, and bifurcations as the geometric parameters of the Kresling pattern are varied. To this end, a mathematical model which assumes that the different panels can be represented by axially deformable truss elements is adopted. The adopted model demonstrates that the shape of the potential energy of the spring is very sensitive to changes in its geometric parameters. This causes the static configuration to undergo several bifurcations as one or more of the geometrical parameters are varied. In particular, it is shown that the geometric parameter space of the Kresling pattern can be divided into five regions, each of which results in a qualitatively different spring behavior. Results of the axial truss model are verified experimentally demonstrating that, for the most part, the model is capable of predicting the loci and bifurcations of the spring's equilibria. Nevertheless, it is also observed that, away from the equilibrium points, the quasistatic behavior of the spring is not well-approximated by the axial truss model. To overcome this issue, a modified model is developed which accounts for (i) the rotary stiffness of the creases, (ii) self avoidance due to panel contact at small angles between the panels, and (iii) buckling of the creases under compressive loads. It is shown that the modified model is capable of providing a better overall qualitative approximation of the quasistatic behavior.