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1. Using electrodermal activity to validate multilevel pain stimulation in healthy volunteers evoked by thermal grills

   https://doi.org/10.1152/ajpregu.00102.2020  

   Posada-Quintero, Hugo F.; Kong, Youngsun; Nguyen, Kimberly; Tran, Cara; Beardslee, Luke; Chen, Longtu; Guo, Tiantian; Cong, Xiaomei; Feng, Bin; Chon, Ki H. (September 2020, American Journal of Physiology-Regulatory, Integrative and Comparative Physiology)

   null (Ed.)

   We have tested the feasibility of thermal grills, a harmless method to induce pain. The thermal grills consist of interlaced tubes that are set at cool or warm temperatures, creating a painful “illusion” (no tissue injury is caused) in the brain when the cool and warm stimuli are presented collectively. Advancement in objective pain assessment research is limited because the gold standard, the self-reporting pain scale, is highly subjective and only works for alert and cooperative patients. However, the main difficulty for pain studies is the potential harm caused to participants. We have recruited 23 subjects in whom we induced electric pulses and thermal grill (TG) stimulation. The TG effectively induced three different levels of pain, as evidenced by the visual analog scale (VAS) provided by the subjects after each stimulus. Furthermore, objective physiological measurements based on electrodermal activity showed a significant increase in levels as stimulation level increased. We found that VAS was highly correlated with the TG stimulation level. The TG stimulation safely elicited pain levels up to 9 out of 10. The TG stimulation allows for extending studies of pain to ranges of pain in which other stimuli are harmful. 

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2. Marine phytoplankton functional types exhibit diverse responses to thermal change

   https://doi.org/10.1038/s41467-021-26651-8  

   Anderson, S. I.; Barton, A. D.; Clayton, S.; Dutkiewicz, S.; Rynearson, T. A. (November 2021, Nature Communications)

   Abstract Marine phytoplankton generate half of global primary production, making them essential to ecosystem functioning and biogeochemical cycling. Though phytoplankton are phylogenetically diverse, studies rarely designate unique thermal traits to different taxa, resulting in coarse representations of phytoplankton thermal responses. Here we assessed phytoplankton functional responses to temperature using empirically derived thermal growth rates from four principal contributors to marine productivity: diatoms, dinoflagellates, cyanobacteria, and coccolithophores. Using modeled sea surface temperatures for 1950–1970 and 2080–2100, we explored potential alterations to each group’s growth rates and geographical distribution under a future climate change scenario. Contrary to the commonly applied Eppley formulation, our data suggest phytoplankton functional types may be characterized by different temperature coefficients (Q₁₀), growth maxima thermal dependencies, and thermal ranges which would drive dissimilar responses to each degree of temperature change. These differences, when applied in response to global simulations of future temperature, result in taxon-specific projections of growth and geographic distribution, with low-latitude coccolithophores facing considerable decreases and cyanobacteria substantial increases in growth rates. These results suggest that the singular effect of changing temperature may alter phytoplankton global community structure, owing to the significant variability in thermal response between phytoplankton functional types. 

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3. Exploring the Impact of Green Walls on Occupant Thermal State in Immersive Virtual Environment

   https://doi.org/10.3390/su14031840  

   Sedghikhanshir, Alireza; Zhu, Yimin; Chen, Yan; Harmon, Brendan (February 2022, Sustainability)

   Green walls have been used in built environments as a natural element to bring various benefits, thus improving human health and well-being. However, in conventional virtual environments, the visual connection with a green wall is the only way that this natural element could benefit humans. Unfortunately, the impact of such visual connection on human thermal perception is still not well understood. Thus, we conducted an experimental study with 40 participants comparing the thermal state of two virtual sessions: biophilic (a room with a green wall) and non-biophilic (the same room without a green wall). Both sessions were conducted in a climate chamber under a slightly warm condition (28.89 °C and 50% relative humidity). Participants’ thermal state, skin temperature, and heart rate data were collected. According to the results, participants’ thermal comfort and hand skin temperature were significantly different between the two sessions, and their mean skin temperature was statistically increased over time. The study suggests that before the extent to which the impact of visual stimuli (e.g., green walls) on thermal perception is fully understood, researchers may need to control visual and thermal stimuli separately when using them in immersive virtual environments. Furthermore, the virtual exposure time should be an important consideration when designing experimental procedures. 

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4. Colour in AR and VR

   Murdoch, Michael J (October 2023, John Wiley & Sons, Ltd)

   Green, Phil (Ed.)

   Head‐mounted virtual reality (VR) and augmented reality (AR) systems deliver colour imagery directly to a user's eyes, presenting position‐aware, real‐time computer graphics to create the illusion of interacting with a virtual world. In some respects, colour in AR and VR can be modelled and controlled much like colour in other display technologies. However, it is complicated by the optics required for near‐eye display, and in the case of AR, by the merging of real‐world and virtual visual stimuli. Methods have been developed to provide predictable colour in VR, and ongoing research has exposed details of the visual perception of real and virtual in AR. Yet, more work is required to make colour appearance predictable and AR and VR display systems more robust. 

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5. Emotional Response to Vibrothermal Stimuli

   https://doi.org/10.3390/app11198905  

   Shetty, Yatiraj; Mehta, Shubham; Tran, Diep; Soni, Bhavica; McDaniel, Troy (October 2021, Applied Sciences)

   Emotional response to haptic stimuli is a widely researched topic, but the combination of vibrotactile and thermal stimuli requires more attention. The purpose of this study is to investigate emotional response to vibrothermal stimulation by combining spatiotemporal vibrotactile stimulus with dynamic thermal stimulus (hot or cold). The vibrotactile and thermal stimuli were produced using the Haptic Chair and the Embr wave thermal bracelet, respectively. The results show that spatiotemporal vibrotactile patterns and their duration, and dynamic thermal stimulation, have an independent effect on the emotional response. Increasing duration generally increases the valence and arousal of emotional response. Shifting the dynamic temperature from cold to hot generally decreases the valence of emotional response but has no significant effect on arousal. Nevertheless, certain spatiotemporal patterns do exhibit unique responses to changes in dynamic temperature, although no interaction effects were found. The results show the potential of designing affective haptic interfaces using multimodal vibrothermal feedback. 

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