Temperature Sensation Research Articles

The role of TRPV4 channels in cutaneous epithelia.

Transient receptor potential vanilloid 4 (TRPV4) channels are multi-modally activated cation permeable channels that are expressed most organ tissues including the skin. TRPV4 is highly expressed in the skin and functions in skin resident cells such as epidermal keratinocytes, melanocytes, immune mast cells and macrophages, and cutaneous neurons. TRPV4 plays many crucial roles in skin homeostasis to affect an extensive range of processes such as temperature sensation, osmo-sensation, hair growth, cell apoptosis, skin barrier integrity, differentiation, nociception and itch. Since TRPV4 functions in a plenitude of pathological states, TRPV4 can become a versatile therapeutic target for diseases such as chronic pain, itch and skin cancer.

Independent Microscale Sensing of Phase Interface and Surface Temperature During Droplet Evaporation

Independent Microscale Sensing of Phase Interface and Surface Temperature During Droplet Evaporation

Multi-Parameter Sensing and Demodulation of Temperature, Salinity and Pressure in Seawater Based on the Semi-Encapsulated Microfiber Mach-Zehnder Interferometer

Multi-Parameter Sensing and Demodulation of Temperature, Salinity and Pressure in Seawater Based on the Semi-Encapsulated Microfiber Mach-Zehnder Interferometer

The effect of diffuse ceiling ventilation air supply on human thermal comfort under radiant asymmetry

Sidewall radiant heating creates a non-uniform thermal environment. In office buildings, it is important to know how to supply fresh air to reduce radiant asymmetry without causing draft. As a solution, diffuse ceiling ventilation (DCV) is used to supply fresh air into a sidewall radiant heated room. 20 subjects (10 males and 10 females) were recruited and subjective assessments were obtained. The results show that under the influence of sidewall radiant heating, there are differences in the subjects’ requirements for airflow and wall temperature on both body sides. Skin temperature and thermal sensation of the same body parts decrease differently when the subjects move away from the radiant heating panels, especially in forearms, shanks and feet. DCV airflow with low supply momentum interacts with thermal plume formed by radiant heating panels.

Multifunctional thermo-magnetically actuated hybrid soft millirobot based on 4D printing

Soft materials, which use both internal energy change and external energy supply to produce shape morphing and motion, are essential for the development of robotics. Four-dimensional (4D) printing is a promising method for fabricating soft robots with arbitrary structures. However, there are still few hybrid soft robots that can be manufactured by 4D printing because of the physicochemical nature of the materials. In this study, a novel smart hydrogel composed of NIPAM, Laponite nanoclay, and NdFeB magnetic particles, which have simultaneous temperature sensation and magnetic actuation, was synthesized for 4D printing of robots. It has been proven that this material has good mechanical properties and excellent machinability and biocompatibility. Soft millirobots with different structures and functions were printed, including a catheter with a multi-segment magnetic head, a leptasteria-like robot, and a shellfish-like robot, which can respond to both magnetic and thermal fields. The locomotion of the millirobot has been verified to overcome physical obstacles in the human stomach model and complete active transportation of cargo. The synergistic responses to the magnetic field and thermal field make the robot more adaptable and reduce the leakage of drugs during transportation. The 4D printed soft millirobots will promote the application prospects of robots in the fields of bioengineering and medical treatment.

Opalski syndrome: A rare presentation of Wallenberg syndrome

Lateral Medullary Syndrome (LMS) is a well studied vascular syndrome of the posterior circulation territory. This syndrome is localised with its typical presentation including vertigo, nystagmus, hoarseness, dysphagia, ipsilateral cerebellar signs and Horner’s syndrome with classical crossed sensory deficits, specifically loss of pain and temperature sensation affecting trunk and extremities contralateral to the infarct along with ipsilateral facial numbness. We present a case of Opalski syndrome which is a rare variant of Wallenberg syndrome, where lateral medullary syndrome is associated with ipsilateral hemiparesis and positive Babinski sign. This case report showcases one of the varied presentation of ipsilateral weakness in Lateral Medullary Syndrome or Wallenberg syndrome.

An experimental study on the thermal performance of mixed phase change materials-based battery cooling system

Phase change materials (PCMs) have been widely used in the battery thermal management system (BTMS) due to their excellent cooling efficiency. Previous studies mainly focused on the effect of pure PCM with onefold phase change temperature (PCT) on cooling the battery, while the battery temperature generally varies in a wide range, especially under abuse conditions, which tends to cause the underutilization or exhaustion of the latent heat of the PCM. This paper experimentally investigates the thermal performance of mixed PCMs with different PCTs (37 and 58 ℃, i.e. PCM-37 and PCM-58) by means of a laboratory-scale PCM-based battery cooling system, seeking to obtain the optimal mixing ratio at various ambient temperatures (30, 40, 50 ℃). The experimental results show that the cooling performance of the mixed PCM is satisfying, especially at the ambient temperatures of 30 ℃ and 40 ℃, where the optimal proportion of (PCM-37: PCM-58) is 3:1 and 1:3, respectively. However, at 50 ℃, the pure PCM-58 exhibits the best cooling effectiveness, since the latent heat of PCM-37 is exhausted at high ambient temperature, and the presence of PCM-37 will weaken the heat dissipation effect. The findings above quantitatively demonstrate the advantage of mixed PCMs on cooling the cycling battery at elevated ambient temperatures. In light of the temperature sensibility of PCM, this work provides a novel insight into the improvement of PCM-based BTMSs.

Investigating cold Aδ fibers in the 0–40 °C temperature range: A quantitative sensory testing and evoked potentials study

ObjectiveTo evaluate the activity of cold Aδ-type fibers to thermal stimuli above human skin temperature (i.e., >32 °C). MethodsTwenty young adults aged 20–24 years participated in this study. The cold-detection threshold was measured from a basal temperature of 40 °C using an adaptive staircase method with high-speed cooling ramps (170 °C/s). A total of 150 stimulations at 36 °C, 32 °C, 28 °C, 24 °C, 20 °C, 16 °C, 12 °C, 8 °C, 4 °C and 0 °C (15 each) were performed. After each stimulation, subjects estimated the intensity of cold sensation using a visual analog scale, and evoked potentials were recorded. ResultsThe average cold-detection threshold was 35 °C (SD = 1.8). Regardless of the stimulation temperature, subjects reported a cooling sensation. Interestingly, reported increments in sensation were prominent for stimulation temperatures between 32 °C and 20 °C, but below this latter temperature sensations varied only very slightly. Evoked potential recordings revealed that decreasing temperature stimuli from a baseline of 40 °C induced a previously unreported N2P2 component with a mean N2 peak latency of 275 ms (SD = 13.1). The peak-to-peak amplitude of the N2P2 complex increased as the intensity of the cooling stimulation increased, exhibiting a profile comparable to subject-perceived intensity, namely, a major increase up to 20 °C, followed by a plateau to 0 °C. ConclusionsThe cool sensations reported by subjects were likely conveyed by Aδ fibers rather than by slow-conducting C fibers. Moreover, our rapid stimulation technique starting from a high temperature (40 °C) was capable of a) generating cold sensations at stimulation temperatures between 36 °C and 32 °C, and b) revealing the optimal activation range of Aδ fibers (20 °C–28 °C). Any decrease in temperature below this range did not result in a significant increase in sensation and thus probably did not evoke a significant increase in Aδ fiber activity. SignificanceThe regular assessment of cold sensation in peripheral neuropathies (i.e., with temperatures below 32 °C), could be completed by investigating cold-detection thresholds at temperatures ranging from 40 °C to 32 °C. Indeed, the absolute threshold of cold perception appears to start at 35 °C. Changes in the activation threshold of cold fibers were more easily detectable at this level.

A methodology to assess mixer performance for selective catalyst reduction application in hot air gas burner

The active SCR aftertreatment system is one of the most crucial technology for the NOx reduction of diesel engines. One of the essential parameters of this technology is the urea spray performance on the catalyst. This study presents an experimental and numerical investigation of urea spray behavior used in the heavy-duty diesel engine's selective catalytic reduction (SCR) aftertreatment systems.The custom test rig is designed and built to simulate exhaust aftertreatment systems of heavy-duty diesel vehicles. Urea injector parameters were observed in this test rig with optic windows for spray and flow visualization. This test rig is available to simulate diesel engines in the sense of exhaust mass flow rate, temperature and spray control unit. The discussion is made about the effects of droplet size of spray and velocity distribution upon flow characterization.A detailed assessment of the numerical model was presented, and validation was carried out for different interest measurement locations. The predicted droplet size distributions, breakup performance, and velocities are numerically and correlated with the experimental data. The validated model is subsequently used to study the urea-flow mixing dynamics to develop a urea mixer numerically. Test results show that smaller droplets enhance the mixing and thus catalyst efficiency. Mixer design performance can be assessed numerically in the droplet size break up based on the developed criteria called mixer performance criteria. Upstream and downstream of the mixer, droplet size can be extracted from the simulation, and different mixer designs can be compared in terms of the breakup performance.

Harmony and Disharmony: Acoustic Opposition in the Early Lyrics of Alexander Blok

The article studies the role of the observer - the subject of acoustic perception of poetic narrative, in particular, in the construction of a dual reality in the early work by Alexander Blok Poems about the Beautiful Lady. Acoustic perceptual data is the basis for the creation of complex mystical and philosophical symbols and poetic images. The divine, ideal world of the Beautiful Lady and the real world of the lyric hero are in opposition to each other in acoustic terms, which give rise to the opposition HARMONY - DISHARMONY. The opposition is realized in musical sounds, songs, and bell ringing typical of the upper world. The real world is characterized by other sounds, non-musical: groans, creaks, complaints, and crying. Accordingly, emotions also differ in value depending on belonging to one or another world: in the world of the Beautiful Lady they quietly laugh, rejoice; in the world of the lyrical hero they cry, moan, complain. SILENCE is a significant symbol of the divine world. The world of the Beautiful Lady is thus harmonious, musical and quiet. Its important element is the voices of birds: swans, cranes, eagles. Smell, touch and taste play a minor role in the creation of the Bloks dual reality. Temperature sensations participate in the formation of the COLD symbol as a phenomenon hostile to the divine world. Thus, the concept of dual reality in Bloks early lyrics is embodied in a number of acoustic oppositions and acoustic symbols of silence, song, and bell ringing.

The problem of brief interaction of two amorphous bodies

The author has proposed a model of brief interaction of two amorphous bodies with boundary conditions of the third and fourth kind in the amorphous body without a convective massflux. Consideration has been given to the thermophysical aspect of formation of the temperature sensation of a biomedical object (BMO) on contact with the amorphous body with a different temperature. The procedure of short measurements in the stage of irregular thermal regime (pulse method) was applied to investigation of thermal conductivity of various anatomical sections of the BMO skin as a function of its temperature. It has been shown experimentally that thermal conductivity grows with temperature and is within 0.29–0.48 W/(m K). The total relative error of the method of thermal conductivity measurements amounted to ∼ 5%. It has been proposed that analytical calculation of the surface temperature of the BMO on contact be modeled as a combination of the temperatures in liquid and solid media by using the criterion of moisture-content percentage in the BMO.

A novel SNP of TECPR2 gene associated with heat tolerance in Chinese cattle

Heat stress affects the animal production and causes serious economic losses to the husbandry. Tectonin beta-propeller repeat containing 2 (TECPR2) gene plays an important role in autophagy which may affect the temperature sensation in animals. A missense mutation (XM_024981840.1:c.3989 G > A p.Arg1330His) of the transcripts X4 in the bovine TECPR2 gene was identified. In this study, the c.3989 G > A variant in TECPR2 gene was genotyped in a total of 25 cattle breeds (520 individuals). Our results indicated that the frequency of A allele showed a decreasing pattern from southern cattle to northern cattle, while the frequency of G allele showed the opposite pattern, which was consistent with the climate distribution of China. Compared with the GG genotype, southern cattle carried more the AA and AG genotypes. Furthermore, the association results carried out that the frequencies of genotypes (GG, AG, AA) and the value of climate parameters (mean annual temperature (T), relative humidity (RH) and temperature humidity index (THI) were significantly correlated (p < 0.01). Hence, we speculated that the c.3989 G > A variant of TECPR2 gene was associated with the heat tolerance trait in Chinese cattle and the locus may be considered as a molecular marker for Chinese cattle breeding.

Animal models and experimental medicine and the Nobel Prize in Physiology or Medicine 2021-TRPV and PIEZO receptors for temperature and touch sensation.

Animal models and experimental medicine and the Nobel Prize in Physiology or Medicine 2021-TRPV and PIEZO receptors for temperature and touch sensation.

The science of “smell” and the noble for “hugs:” making “sense?”

David Julius and Ardem Patapoutian were jointly awarded the 2021 Nobel Prize in Physiology and Medicine for their discoveries of receptors for temperature and touch. It was a phenomenal moment for the scientific community, more for the discovery that forms the basic fabric of our everyday life—ever imagined how life would have been without feeling the aroma around? Or even the dangers of accidentally touching a heated object. Dr Julius and Dr Patapoutian, independently discovered key mechanisms of how living organisms sense heat, cold, and touch. The journey started when Dr Julius, at the University of California, San Francisco, used a key ingredient in hot chili peppers to identify a protein in nerve cells that respond to these stimuli. Using capsaicin, the pungent component of chili peppers, he provided fundamental insights into mechanisms of pain. Then using a meticulous cDNA library-based functional screening from sensory neurons to search for the gene(s) that could confer capsaicin sensitivity, Dr Julius identified for the first time a novel ion channel (now called transient receptor potential [TRP] vanilloid 1) belonging to the family of TRP ion channels associated with the pain sensitivity. A painful exercise indeed! While Prof Julius was exploring the oceans and skies to hunt for sensory pain pathways, quite independently, Dr Patapoutian of Scripps Research Institute La Jolla, California, was searching for a similar thing that seemed to bother him equally. How do we sense touches? After all, there are so many emotions packaged in this small five-letter word, touch. The mother’s touch is the first sensation that every single of us always cherishes. Dr Patapoutian research is centered around finding candidate genes in a mechanosensitive cell line that could respond to mechanical stimuli. After a thorough search, the team identified two mechanically-activated ion channels, PIEZO1 and PIEZO2, representing an entirely novel class of mechanical sensors-based ion channels. What is fascinating is the idea that discovery of the smell and touch receptor stretches far beyond just touch and temperature sensations only. Mutations in other TRP channels are involved in neurodegenerative disorders and skeletal dysplasia, while mutations in PIEZO channels help control critical functions such as respiration and blood pressure regulation. So now, the mysterious world surrounding us looks more transparent and clearer. The molecular landscape is defined with precision. We now have a chemical entity behind all these emotions and intuition. The warm hug that makes our day is now millions of ions crisscrossing the ion channels. There is a different side to this too. How will the world look if everything is defined as a chemical entity? Won’t we lose the charm? After all, so much within the subtleness remains charmful when wrapped within the veil of ignorance. Knowing too much about something steals the show.

Skin Advanced Glycation End Products among Subjects with Type 2 Diabetes Mellitus with or without Distal Sensorimotor Polyneuropathy

Materials and Methods We included 132 subjects (88 men) with a mean age of 64.57 years and median T2DM duration of 14.5 years. Skin AGEs were measured with AGE reader mu connect (Diagnoptics) on the dominant arm. The device enables single and automated triplicate measurements: both of these were performed. DSPN was diagnosed through the neuropathy disability score (NDS). Small nerve fibre function was assessed by temperature and pinprick sensation on the foot. Bilateral measurement of the vibration perception threshold (VPT) on the hallux was carried out by using a neurothesiometer (Horwell Scientific Laboratory Supplies). Results Single and triplicate AGE measurements were positively correlated with each other (Pearson's correlation coefficient r = 0.991, 95%CI = 0.987-0.994, p < 0.001). AGEs were higher among subjects with vs. those without DSPN (p < 0.001). Furthermore, they were higher among subjects with reduced vs. normal temperature sensation (p < 0.001), among subjects with reduced vs. normal pinprick sensation (p = 0.002), among those with abnormal vs. normal monofilament examination (p < 0.001), and among those with abnormal vs. normal VPT (p < 0.001). AGEs were correlated with NDS, VPT, and monofilament score. Conclusions In T2DM, skin AGEs are increased in the presence of DSPN. This holds true both for large and for small nerve function impairment. Moreover, AGEs are correlated with DSPN severity.

Pregnancy following Brown-Séquard syndrome: A rare case report

Brown-Séquard syndrome is an incomplete spinal cord lesion characterized by hemisection injury of the cord. We present a case of pregnancy, delivery and postpartum course following this rare neurological condition. A 42-year-old woman presented with past history of idiopathic hemicord myelitis leading to right sided hemiplegia with decreased contralateral sensation of pain and temperature, consistent with Brown-Séquard syndrome, which was treated with steroids and Therapeutic Plasma Exchange. Thereafter, she had near-complete motor recovery and complete sensory recovery over the next 3months. Three years later, she presented to us at 37+2 weeks of gestation with residual hemiparesis with motor power grade of 4/5 in right upper and lower limbs. She underwent Caesarean section for breech presentation, which was done under general anaesthesia in view of prior spinal cord lesion. She was discharged for follow-up in Neurology outpatient clinic and physical rehabilitation. At follow up after 12 months of delivery, she had complete motor and sensory recovery. Management of spinal cord lesions in pregnancy and delivery requires specialist multidisciplinary care due to risk of medical and obstetric complications. This case demonstrates a rare scenario of a primigravida at term gestation with residual deficits of a past spinal cord lesion.

Congenital insensitivity to pain: a novel mutation affecting a U12-type intron causes multiple aberrant splicing of SCN9A.

Mutations in the alpha subunit of voltage-gated sodium channel 1.7 (NaV1.7), encoded by SCN9A gene, play an important role in the regulation of nociception and can lead to a wide range of clinical outcomes, ranging from extreme pain syndromes to congenital inability to experience pain. To expand the phenotypic and genotypic spectrum of SCN9A-related channelopathies, we describe the proband, a daughter born from consanguineous parents, who had pain insensitivity, diminished temperature sensation, foot burns, and severe loss of nociceptive nerve fibers in the epidermis. Next-generation sequencing of SCN9A (NM_002977.3) revealed a novel homozygous substitution (c.377+7T>G) in the donor splice site of intron 3. As the RNA functional testing is challenging, the in silico analysis is the first approach to predict possible alterations. In this case, the computational analysis was unable to identify the splicing consensus and could not provide any prediction for splicing defects. The affected intron indeed belongs to the U12 type, a family of introns characterised by noncanonical consensus at the splice sites, accounting only for 0.35% of all human introns, and is not included in most of the training sets for splicing prediction. A functional study on proband RNA showed different aberrant transcripts, where exon 3 was missing and an intron fragment was included. A quantification study using real-time polymerase chain reaction showed a significant reduction of the NaV1.7 canonical transcript. Collectively, these data widen the spectrum of SCN9A-related insensitivity to pain by describing a mutation causing NaV1.7 deficiency, underlying the nociceptor dysfunction, and highlight the importance of molecular investigation of U12 introns' mutations despite the silent prediction.

Detection of locomotion deficit in a post-traumatic syringomyelia rat model using automated gait analysis technique.

Syringomyelia (SM) is a spinal cord disorder in which a cyst (syrinx) filled with fluid forms in the spinal cord post-injury/disease, in patients syrinx symptoms include loss of pain and temperature sensation or locomotion deficit. Currently, there are no small animal models and connected tools to help study the functional impacts of SM. The objective of this study was to determine the detectability of subtle locomotion deficits due to syrinx formation/expansion in post-traumatic syringomyelia (PTSM) rat model using the recently reported method of Gait Analysis Instrumentation, and Technology Optimized for Rodents (GAITOR) with Automated Gait Analysis Through Hues and Areas (AGATHA) technique. First videos of the rats were collected while walking in an arena (using GAITOR) followed by extracting meaningful locomotion information from collected videos using AGATHA protocol. PTSM injured rats demonstrated detectable locomotion deficits in terms of duty factor imbalance, paw placement accuracy, step contact width, stride length, and phase dispersion parameters compared to uninjured rats due to SM. We concluded that this technique could detect mild and subtle locomotion deficits associated with PTSM injury, which also in future work could be used further to monitor locomotion responses after different treatment strategies for SM.

The specifics of the physiological stress of the population in self-isolation due to the COVID-19 pandemic

Introduction. The COVID-19 pandemic has forced national governments to take measures to prevent the spread of coronavirus. Self-isolation as one of the forms of protection against infection with viral diseases has led to an increase in physiological stress. The purpose of the study is to identify the specifics of the physiological stress of the population in self-isolation due to the COVID-19 pandemic. Material and methods. The study involved 638 students (average age - 23.38 years) undergraduate, specialist and graduate programs of full-time and part-time forms of analysis who went online during the period of self-isolation via Skype to participate in training sessions. Questionnaires were used: “What stress are you experiencing?” (P. Legeron), “Inventory of stress symptoms” (T. Ivanchenko), neuropsychic stress questionnaire (T.A. Nemchin), Toronto alexithymia scale (G.J. Taylor, D. Ryan, R.M. Bagby). Mathematical and statistical data processing - K. Pearson’s correlation criterion and Chaddock’s table. Results. Both the average level of physiological stress (6.74) and its components with a high connection were revealed: severity, increase, duration and frequency of neuropsychic stress (0.84, 0.86, 0.76, 0.86); disturbed sleep and wakefulness (0.82); negative sensations of the activity of the cardiovascular system (0.79), respiratory organs (0.80); pain and temperature sensations (0.73 and 0.75); drop in muscle tone (0.81); physical discomfort (0.84); increased susceptibility to external stimuli (0.87); decreased physical activity (0.79). Discussion. The results of studies by domestic and foreign doctors and psychologists confirm the need for diagnostics, prevention and correction of all types of stress conditions and levelling of physiological stress. Conclusion. The revealed specificity of physiological stress (pain in different parts of the body, dizziness and headaches, poor sleep, stiffness of movements, difficulty in breathing, an increase in the amount of food, coffee, cigarettes, fatigue, heart palpitations and physical stress) provides a basis for the management of primary and secondary prevention of general, physiological and emotional stress with the involvement of doctors, physiologists and psychologists.

Conceptual Method of Temperature Sensation in Bionic Hand by Extraordinary Perceptual Phenomenon.

Lack of temperature sensation of myoelectric prosthetic hand limits the daily activities of amputees. To this end, a non-invasive temperature sensation method is proposed to train amputees to sense temperature with psychophysical sensory substitution. In this study, 22 healthy participants took part besides 5 amputee participants. The duration time of the study was 31 days with five test steps according to the Leitner technique. An adjustable temperature mug and a Peltier were used to change the temperature of the water/phantom digits to induce temperature to participants. Also, to isolate the surroundings and show colors, a Virtual Reality (VR) glass was employed. The statistical results conducted are based on the response of participants with questionnaire method. Using Chi-square tests, it is concluded that participants answer the experiment significantly correctly using the Leitner technique (P value < 0.05). Also, by applying the “Repeated Measures ANOVA”, it is noticed that the time of numbness felt by participants had significant (P value < 0.001) difference. Participants could remember lowest and highest temperatures significantly better than other temperatures (P value < 0.001); furthermore, the well-trained amputee participant practically using the prosthesis with 72.58% could identify object’s temperature with only once time experimenting the color temperature.