Thermal Thresholds Research Articles

Antinociceptive and anesthetic-sparing effects of levomethadone/fenpipramide cannot be enhanced by coadministration of metamizole in awake and anesthetized Beagles.

To determine the effect of levomethadone/fenpipramide and metamizole alone and in combination on acute nociception. 8 healthy, adult Beagles were used in 2 separate randomized, complete crossover, experimental trials (threshold testing and determination of minimal alveolar concentration [MAC]) with masked observers. In both trials, treatments were 0.2 mg·kg-1 levomethadone/fenpipramide (L), 75 mg·kg-1 metamizole (M), or their combination (LM). In conscious dogs, mechanical thresholds were determined using constantly rising force. Thermal thresholds were measured via ramped contact heat. The MAC of sevoflurane was determined using the bracketing method with electrical stimulus (50 V, 50 Hz, 10 ms) before and 1 and 4 hours after treatment. Mechanical thresholds in L and LM were significantly increased above baseline (BL) for 165 minutes and above M for 135 minutes. Percent thermal threshold excursion significantly increased above BL in L for 75 minutes and in LM for 135 minutes. In L and LM, the percent thermal threshold excursion was significantly higher than in M from 15 to 75 or 135 minutes, respectively. In L and LM, the MAC of sevoflurane was significantly reduced at 1 hour compared to BL and M. Duration but not the magnitude of thermal antinociception of levomethadone/fenpipramide was increased by metamizole. Mechanical antinociception in awake dogs and anesthetic-sparing effects of levomethadone/fenpipramide were not altered. Coadministration of levomethadone/fenpipramide and metamizole to increase antinociception is not justified.

Hot topic: Mapping of the human intranasal mucosal thermal sensitivity: A clinical study on thermal threshold and trigeminal receptors.

The olfactory and trigeminal system are closely interlinked. Existing literature has primarily focused on characterizing trigeminal stimulation through mechanical and chemical stimulation, neglecting thermal stimulation thus far. The present study aimed to characterize the intranasal sensitivity to heat and the expression of trigeminal receptors (transient receptor potential channels, TRP). A total of 20 healthy participants (aged 21-27 years, 11 women) were screened for olfactory function and trigeminal sensitivity using several tests. Under endoscopic control, a thermal stimulator was placed in 7 intranasal locations: anterior septum, lateral vestibulum, interior nose tip, lower turbinate, middle septum, middle turbinate, and olfactory cleft to determine the thermal threshold. Nasal swabs were obtained in 3 different locations (anterior septum, middle turbinate, olfactory cleft) to analyze the expression of trigeminal receptors TRP: TRPV1, TRPV3, TRPA1, TRPM8. The thermal threshold differed between locations (p = 0.018), with a trend for a higher threshold at the anterior septum (p = 0.092). There were no differences in quantitative receptor expression (p = 0.46) at the different sites. The highest overall receptor RNA expression was detected for TRPV1 over all sites (p<0.001). The expression of TRPV3 was highest at the anterior septum compared to the middle turbinate or the olfactory cleft. The thermal sensitivity correlated with olfactory sensitivity and results from tests were related to trigeminal function like intensity ratings of ammonium, a questionnaire regarding trigeminal function, nasal patency, and CO2 thresholds. However, no correlation was found between receptor expression and psychophysical measures of trigeminal function. This study provided the first insights about intranasal thermal sensitivity and suggested the presence of topographical differences in thermal thresholds. There was no correlation between thermal sensitivity and trigeminal mRNA receptor expression. However, thermal sensitivity was found to be associated with psychophysical measures of trigeminal and olfactory function.

High heat tolerance, evaporative cooling, and stomatal decoupling regulate canopy temperature and their safety margins in three European oak species.

Heatwaves and soil droughts are increasing in frequency and intensity, leading many tree species to exceed their thermal thresholds, and driving wide-scale forest mortality. Therefore, investigating heat tolerance and canopy temperature regulation mechanisms is essential to understanding and predicting tree vulnerability to hot droughts. We measured the diurnal and seasonal variation in leaf water potential (Ψ), gas exchange (photosynthesis Anet and stomatal conductance gs), canopy temperature (Tcan), and heat tolerance (leaf critical temperature Tcrit and thermal safety margins TSM, i.e., the difference between maximum Tcan and Tcrit) in three oak species in forests along a latitudinal gradient (Quercus petraea in Switzerland, Quercus ilex in France, and Quercus coccifera in Spain) throughout the growing season. Gas exchange and Ψ of all species were strongly reduced by increased air temperature (Tair) and soil drying, resulting in stomatal closure and inhibition of photosynthesis in Q. ilex and Q. coccifera when Tair surpassed 30°C and soil moisture dropped below 14%. Across all seasons, Tcan was mainly above Tair but increased strongly (up to 10°C > Tair) when Anet was null or negative. Although trees endured extreme Tair (up to 42°C), positive TSM were maintained during the growing season due to high Tcrit in all species (average Tcrit of 54.7°C) and possibly stomatal decoupling (i.e., Anet ≤0 while gs >0). Indeed, Q. ilex and Q. coccifera trees maintained low but positive gs (despite null Anet), decreasing Ψ passed embolism thresholds. This may have prevented Tcan from rising above Tcrit during extreme heat. Overall, our work highlighted that the mechanisms behind heat tolerance and leaf temperature regulation in oak trees include a combination of high evaporative cooling, large heat tolerance limits, and stomatal decoupling. These processes must be considered to accurately predict plant damages, survival, and mortality during extreme heatwaves.

A novel cinnamic and caffeic acid-conjugated peptide analogs with anticonvulsant and analgesic potency: Comparative analyses of trans/cis isomers.

The novel cinnamic acid (CA) (H4-CA, H5-CA, and H7-CA) and caffeic acid (KA) (H4-KA, H5-KA, and H7-KA) hemorphin analogs have recently been synthesized and their trans isomers have been tested for antiseizure and antinociceptive activity. In the present study, the cis forms of these compounds were tested and compared with their trans isomers in seizure and nociception tests in mice. The cis-H5-CA and H7-CA compounds showed efficacy against psychomotor seizures, whereas the trans isomers were ineffective. Both the cis and trans KA isomers were ineffective in the 6-Hz test. In the maximal electroshock (MES) test, the cis isomers showed superior antiseizure activity to the trans forms of CA and KA conjugates, respectively. The suppression of seizure propagation by cis-H5-CA and the cis-H5-KA was reversed by a kappa opioid receptor (KOR) antagonist. Naloxone and naltrindole were not effective. The cis-isomers of CA conjugates and cis-H7-KA produced significantly stronger antinociceptive effects than their trans-isomers. The cis-H5-CA antinociception was blocked by naloxone in the acute phase and by naloxone and KOR antagonists in the inflammatory phase of the formalin test. The antinociception of the KA conjugates was not abolished by opioid receptor blockade. None of the tested conjugates affected the thermal nociceptive threshold. The results of the docking analysis also suggest a model-specific mechanism related to the activity of the cis-isomers of CA and KA conjugates in relation to opioid receptors. Our findings pave the way for the further development of novel opioid-related antiseizure and antinociceptive therapeutics.

Simulation-Informed Power Budget Estimate of a Fully-Implantable Brain-Computer Interface.

This study aims to estimate the maximum power consumption that guarantees a thermally safe operation for a titanium-enclosed chest wall unit (CWU) subcutaneously implanted in the pre-pectoral area. This unit is a central piece of an envisioned fully-implantable bi-directional brain-computer interface (BD-BCI). To this end, we created a thermal simulation model using the finite element method implemented in COMSOL. We also performed a sensitivity analysis to ensure that our predictions were robust against the natural variation of physiological and environmental parameters. Based on this analysis, we predict that the CWU can consume between 378 and 538mW of power without raising the surrounding tissue's temperature above the thermal safety threshold of 2 C. This power budget should be sufficient to power all of the CWU's basic functionalities, which include training the decoder, online decoding, wireless data transmission, and cortical stimulation. This power budget assessment provides an important specification for the design of a CWU-an integral part of a fully-implantable BD-BCI system.

Assessing the winter indoor environment with different comfort metrics in self-built houses of hot-humid areas: Does undercooling matter for the elderly?

Thermal comfort in housing is vital for well-being. Despite hot and humid regions experiencing shorter cold periods compared to heatwaves, vulnerable populations are susceptible to threats from cold snaps. However, existing research overlooks undercooling risks in hot regions during winter. This study examines self-built houses in densely populated, hot and humid areas, mainly occupied by elderly residents. We conducted an on-site measurement recording hourly indoor air temperature, humidity, and black globe temperature during wintertime. Two thermal comfort metrics (aPMV and adaptive regression model) and two resilience metrics (SET degree-hour, Hours of Safety) were used to quantify thermal conditions during cold periods under current and future climate conditions. The results show that undercooling hours in recent years exceed 90 % of wintertime using aPMV index and adaptive regression models. Under future climate scenarios (Representative Concentration Pathways), undercooling hours only decrease by 10 %–25 % from 2020 to 2100 across all metrics. Extreme cold events in 2018 saw SET degree-hours double the thermal resilience threshold, while they pose health risks to the elderly for up to 21 days according to the HOS metrics. This study aims to identify the importance of addressing winter thermal comfort in hot and humid regions and to assess the risk posed by cold snaps to vulnerable populations. By quantifying these risks, the study contributes to better decision-making regarding hot-humid region housing thermal retrofit strategies for architects, engineers, and other stakeholders.

Some like it hot: Seed thermal threshold variation in obligate seeding Acacia pulchella along a climate gradient

Dormancy in seeds is a key persistence mechanism for many flowering plants. Physically dormant (PY) seeds have water impermeable seed coats, and in fire-prone systems a common mechanism for dormancy release is fire-induced soil heating. However, the thermal thresholds innate to seeds with PY may be influenced by vegetation, climate, and fire regimes, varying substantially between populations of the same species. To investigate intraspecific variation of thermal thresholds in PY seeds, we sampled obligate seeding Acacia pulchella (Fabaceae) which produces PY seeds. Sampling was undertaken from 13 populations across a climate gradient of rainfall and temperature, and between two vegetation communities in fire-prone Mediterranean-type ecosystems of south-west Western Australia. To test a range of weather and fire-induced soil heating dormancy-break scenarios, we conducted dry heat shock experiments between 40 and 140 °C for 10 min and scored germination for 16 weeks. We created population-specific thermal performance curves and extracted the dormancy release temperature at which 50 % of the seeds had germinated (DRT50), the optimum dormancy-breaking temperature to stimulate maximum germination (T0), and the lethal temperature at which 50 % of the seeds were killed (LT50). Generalised linear models were used to examine relationships between thermal thresholds and possible vegetation, climate, and fire regime drivers of intraspecific variation in seed traits. We found that thermal thresholds differed between vegetation communities, with thresholds consistently higher in forest-type ecosystems compared to open woodland, and the influence of climate varied significantly between the two communities. Seeds from Jarrah Forest populations had a DRT50 16.0 °C higher, a T0 9.7 °C higher, and LT50 7.8 °C higher than seeds from Banksia woodlands. A high rate of non-dormancy was identified in one population that had lost fire in its system and displayed significant germination after both summer and fire-related temperatures. The PY thermal thresholds modelled here provide insight into the strong influence of variable soil heating as a function of vegetation and fuel dynamics in fire-prone environments. Our findings highlight the significant intraspecific variation for this species and suggest that fire-induced soil heating generated by vegetation characteristics may be an overlooked element of fire regimes shaping seed traits.

In Hot Water: Current Thermal Threshold Methods Unlikely to Predict Invasive Species Shifts in NW Atlantic.

As global temperatures continue to rise, accurate predicted species distribution models will be important for forecasting the movement of range-shifting species. These predictions rely on measurements of organismal thermal tolerance, which can be measured using classical threshold concepts such as Arrhenius break temperatures and critical thermal temperatures, or through ecologically relevant measurements such as the temperature at which reproduction and growth occur. Many species, including invasive species, exhibit thermal plasticity, so these thresholds may change based on ambient temperature, life stage, and measurement techniques. Here, we review thermal thresholds for 15 invertebrate species invasive to the Gulf of Maine. The high degree of variability within a species and between applied conceptual frameworks suggests that modeling the future distribution of these species in all ecosystems, but especially in the rapidly warming northwest Atlantic and Gulf of Maine, will be challenging. While each of these measurement techniques is valid, we suggest contextualization and integration of threshold measurements for accurate modeling.

Projecting exceedance of juvenile salmonid thermal maxima in streams under climate change: A crosswalk from lab experiments to riparian restoration

Abstract Concern over rising water temperatures for freshwater ectotherms has led to application of experimentally derived thermal thresholds to stream temperature models for estimation of streams at high risk of exceeding thermal thresholds under current and future climate conditions. We optimised an approach that links field‐relevant thermal maxima experiments to corresponding stream temperature models and identifies opportunities to reduce stream temperatures through riparian tree growth. We conducted a thermal maxima experiment on cold‐water adapted juvenile Chinook (Oncorhynchus tshawytscha) and coho salmon (Oncorhynchus kisutch) that reflected natural temperatures by using incremental temperature ramping with diel fluctuations (IT‐Dmax) and refit a regionally specific stream temperature model for British Columbia, Canada to directly relate to lab‐derived thresholds. Salmon‐bearing streams across British Columbia were categorised by threshold exceedance risk (i.e., low, moderate, high, severe) based on risk tolerance scenarios for management decision making (i.e., considering a range of prediction intervals [PIs] and stream thermal sensitivities to air temperature). We linked these results directly to riparian management and restoration actions by estimating the potential for riparian tree growth to reduce threshold exceedance risk. Lab‐derived IT‐Dmax endpoints were consistently 24°C (based on the median value between the 7‐day average of the daily maximum and the mean weekly average temperature) across acclimation treatments for both species. Under current conditions, most stream reaches (99.6% using an intermediate risk tolerance scenario) were below the thermal threshold; streams with moderate to high risk of threshold exceedance were projected to increase from 0.4% to 1.5% (total linear stream length of 6,929 km) by end of century. The risk‐averse (high sensitivity, 75% PI) and risk‐tolerant (low sensitivity, 95% PI) scenarios differed by 1,107 km of streams predicted to have a moderate to severe risk of exceeding thresholds by end of century. Maximal riparian tree growth was predicted to shift 670 km of streams from moderate to low exceedance risk under end‐of‐century conditions and intermediate risk tolerance, showing the potential for mitigation from thermal impacts. Our integrative approach tackled several key considerations in identifying streams at high temperature risk for freshwater ectotherms that to date have not been addressed. Furthermore, we showcased the delineation of spatially comprehensive estimates that identify where management mitigation and a specific restoration activity may be most needed to reduce impacts of rising temperatures on rearing salmonids across an extensive region.

Towards Sustainable Living through Thermoneutral Temperature Management in Subtropical Steppe Climates

This study addresses the critical interplay between sustainable living and thermal comfort within residential buildings in subtropical steppe (BSh) climates, particularly in Northern Iraq. With the global imperative to enhance energy efficiency and occupant well-being, this research emphasizes the identification of thermoneutral indoor air temperature ranges that both support sustainable energy use and ensure the occupants’ thermal comfort. By analyzing the acceptable temperature limits across different building orientations during summer and winter, the study utilizes the predicted mean vote–predicted percentage dissatisfied (PMV-PPD) index approach to establish thermal comfort thresholds. The findings reveal that the optimal summer and winter indoor air temperatures are 29.2 °C and 19.4 °C, respectively, with variations across orientations highlighting the significant influence of building directionality on achieving thermoneutral conditions. A wider range of accepted temperatures exists in the eastward orientation in summer (between 26.6 °C and 29.2 °C). The study advances our understanding of sustainable thermal comfort practices, proposing orientation-specific temperature ranges as a cornerstone for reducing energy consumption without compromising occupant comfort in subtropical steppe climates.

Growing degree‐days do not explain moth species' distributions at broad scales

AbstractGrowing degree‐days (GDD), an estimate of an organism's growing season length, has been shown to be an important predictor of Lepidopteran species' distributions and could be influencing Lepidopteran range shifts to climate change. Yet, one understudied simplification in this literature is that the same thermal threshold is used in the calculations of GDD for all species instead of a species‐specific threshold. By characterizing the phenological process influenced by climate, a species‐specific estimate of GDD should improve the accuracy of species distribution models (SDMs). To test this hypothesis, we used published, experimentally estimated thermal thresholds and modeled the current geographic distribution of 30 moth species native to North America. We found that the predictive performance of models based on a species‐specific estimate of GDD was indistinguishable from models based on a standard estimate of GDD. This is likely because GDD was not an important predictor of these species' distributions. Our findings suggest that experimentally estimated thermal thresholds may not always scale up to be predictive at broad scales and that more work is needed to leverage the data from lab experiments into SDMs to accurately predict species' range shifts in response to climate change.

Morin Regulates M1/M2 Microglial Polarization via NF-κB p65 to Alleviate Vincristine-Induced Neuropathic Pain.

Morin can alleviate vincristine-induced neuropathic pain via inhibiting neuroinflammation. Microglial cells play an important role in initiating and maintenance of pain and neuroinflammation. It remains unclear whether morin exerts antinociceptive properties through the regulation of microglial cells. This study aimed to elucidate the mechanisms of morin against neuropathic pain focusing on microglial cells. The thermal withdrawal latency and mechanical withdrawal threshold were used as measures of pain behaviours. Histological abnormalities of the sciatic nerve were observed with transmission electron microscopy. The sciatic functional index and the sciatic nerve conduction velocity were used as measures of the functional deficits of the sciatic nerve. Inflammatory factors were detected using ELISA. The expression of M1/M2 polarization markers of microglia and nuclear factor κB (NF-κB) p65 were measured by immunofluorescence, real-time quantitative PCR and Western blotting. Morin alleviated vincristine-induced abnormal pain, sciatic nerve injury, and neuroinflammatory response in rats. Furthermore, morin decreased the expression of NF-κB P65 and M1 activation markers, increased the expression of M2 activation markers. Additionally, phorbol 12-myristate 13-acetate reversed the effects of morin on microglial polarization, the production of inflammatory factors and neuropathic pain, while ammonium pyrrolidine dithiocarbamate showed the opposite effects. Our results demonstrate that morin inhibits neuroinflammation to alleviate vincristine-induced neuropathic pain via inhibiting the NF-κB signalling pathway to regulate M1/M2 microglial polarization.

Increased crossing of thermal stress thresholds of vegetation under global warming.

Temperature extremes exert a significant influence on terrestrial ecosystems, but the precise levels at which these extremes trigger adverse shifts in vegetation productivity have remained elusive. In this study, we have derived two critical thresholds, using standard deviations (SDs) of growing-season temperature and satellite-based vegetation productivity as key indicators. Our findings reveal that, on average, vegetation productivity experiences rapid suppression when confronted with temperature anomalies exceeding 1.45 SD above the mean temperature during 2001-2018. Furthermore, at temperatures exceeding 2.98 SD above the mean, we observe the maximum level of suppression, particularly in response to the most extreme high-temperature events. When Earth System Models are driven by a future medium emission scenario, they project that mean temperatures will routinely surpass both of these critical thresholds by approximately the years 2050 and 2070, respectively. However, it is important to note that the timing of these threshold crossings exhibits spatial variation and will appear much earlier in tropical regions. Our finding highlights that restricting global warming to just 1.5°C can increase safe areas for vegetation growth by 13% compared to allowing warming to reach 2°C above preindustrial levels. This mitigation strategy helps avoid exposure to detrimental extreme temperatures that breach these thresholds. Our study underscores the pivotal role of climate mitigation policies in fostering the sustainable development of terrestrial ecosystems in a warming world.

Inter-trial Variation in the Sensitivity of Thermal Threshold Testing for the Diagnosis of Neuropathy in Type 2 Diabetes Mellitus.

Thermal threshold testing (TTT) is a simple non-invasive approach for diagnosing diabetic neuropathy earlier. Conventionally the TTT is done in all four limbs and at least 6 trials are done to obtain the mean threshold, which is time consuming. We propose to assess the validity and reliability of reduced number of trials of TTT in the lower limbs. After obtaining ethics approval from the Institute Ethics Committee, 100 patients with type 2 Diabetes Mellitus of both gender between the ages of 35 to 65 years attending medicine OPD were recruited. Neuropathy assessment was done using Temperature threshold testing. At least 6 trials were performed for each site and the mean threshold obtained. The mean of 5 trials, 4 trials and 3 trials were noted for the comparison. On comparing hot tests of 3 trials with 6 trials had a sensitivity and specificity of 88.7% and 96.6 %. In cold threshold testing, 4 trials and 3 trials showed similar results of sensitivity of 77.8%, specificity of 98.8%. The measures of agreement between the hot trials 6 vs 5 had Kappa value of 0.953, 6vs 4 showed a Kappa value of 0.862 and 6 vs 3 showed Kappa value of 0.819. Hot threshold tests of lower limb are more sensitive than cold thresholds. The 4 trial test is a reliable test and can be performed over 6 trial tests. When time is a factor, three trials are sufficient to diagnose small fibre neuropathy.

Feverphobia: Frecuency and related factors associated

Fever is common in childhood and there is a high level of concern on behalf of caregivers to manage it, this is called "feverphobia". The objective was to evaluate the presence of feverphobia and associated factors in the study population. Methods: observational, cross-sectional, prospective, and analytical study during 2021 to 2022 through an ad hoc survey self-administered to parents and/or caregivers of patients under 6 years of age who consulted the emergency room of the Dr. Roberto del Río Children's Hospital in Santiago, Chile. The association between sociodemographic variables, knowledge, attitudes, and fears regarding febrile children was analyzed by Chi square and Fisher’s test in addition to univariate logistic regression analysis. A total of 381 surveys were carried out. 98% presented some degree of feverphobia. A fever below 38°C was defined by 40.6%. Physical measures were used by 56% of caregivers. The main sequelae feared were convulsions in 82% and 42.7% reported that it could be lethal. A total of 92.1% used unreliable sources of information and 66% had never received education from health personnel on this subject. Logistic regression showed that being a parent, basic or high school level and a thermal threshold below 38°C were the most associated variables. Feverphobia is a current phenomenon in our population and health education to the parents and caregivers could prevent it.

Analysis of physical and mechanical behaviors and microscopic mineral characteristics of thermally damaged granite

Temperature’s influence on the physical and mechanical properties of rocks is a crucial concern for the rational design of deep rock engineering structures and the assurance of their long-term stability. To systematically comprehend the impact of the evolution of mineral composition and micro characteristics on the physical and mechanical behavior of thermally damaged granite, we observed the microscopic structural defects inside the rocks with a polarizing microscope and revealed the thermal damage mechanism of granite from a microscopic perspective by combining ultrasound detection and XRD phase characteristic analysis. The results show that the physical properties of the specimens changed significantly at three characteristic temperature points: 400 °C, 800 °C, and 1000 °C. Under high temperature conditions, the diffraction intensity of all minerals in granite, except for quartz, generally decreased, and stable minerals decomposed. Albite and potash feldspar decomposed to form anorthoclase, thereby reducing the structural stability of the rock material. In addition, the peak width of various minerals decreased to varying degrees with increasing temperature. The increase in mineral volume further damaged the internal structure of the rock material while promoting the transformation from grain boundary to intergranular cracks and from intragranular cracks to transgranular cracks, ultimately forming a interconnected crack network. Thermal damage significantly reduced the longitudinal wave velocity, uniaxial compressive strength, and elastic modulus of the specimens, while the stress–strain curve relationship indicated that the specimens underwent two opposite processes of transformation from brittleness to ductility and then from ductility to brittleness. The thermal damage threshold of granite in this study was 600 °C.

Effect of temperature on the development, reproduction and survival of Tetramoera schistaceana (Lepidoptera: Tortricidae)

Tetramoera schistaceana Snellen is an important stem borer of sugarcane, which causes severe damage to sugarcane in China. Temperature is a key factor affecting its development and reproduction. Development duration, reproduction and survival rate of T. schistaceana were determined at five different temperatures (20, 23, 26, 29 and 32 °C) in this study. Results showed that temperature had significant effects on the development duration, survival rate and reproduction of T. schistaceana. The development rate of T. schistaceana for each stage increased linearly with increasing temperatures between 20 and 32 °C. Egg hatching rate, larval pupation rate and pupal eclosion rate were the highest between 23 and 26 °C. The lower thermal threshold (T0) for egg, larva, pupa, pre-adult and whole generation were 9.98, 9.80, 9.47, 9.50 and 8.87 °C, respectively and the thermal constant (K) for the development of the respective life cycle stages of were 89.29 for eggs, 400.00 for larvae, 151.52 for pupae, 625.00 for pre-adult and 666.67DD for whole generation, respectively. The average fecundity per female was also the highest between 23 and 26 °C. Therefore the optimum temperature range for the development and reproduction of T. schistaceana was between 23 and 26 °C.

Somatosensory alterations after single-unit dental implant immediate loading: A 1-year follow-up study

ObjectiveThis cohort study aimed to assess the incidence of somatosensory alterations after implant surgery using standardized quantitative and qualitative sensory testing. Methods33 participants with single-tooth loss, undergoing immediate implant loading were included. Quantitative Sensory Testing (QST) and Qualitative Sensory Testing (QualST) were conducted at eight time points over a year (baseline to 1 year). Two-Way Repeated Measures ANOVA and post hoc Tukey test were used on QST values and Cochran Q test on QualST. ResultsThe study revealed significant increase in thermal thresholds overtime. At the operated side, overall Cold Pain Threshold (extraoral: p = 0.030; intraoral: p < 0.001), and Cold Detection Threshold (intraoral: p < 0.001) increased overtime. In contralateral region, maxilla Cold Detection Threshold (extraoral: p = 0.024; intraoral: p = 0.031), Warm Detection Threshold (extraoral: p = 0.026; intraoral: p = 0.047) and overall Cold Pain Threshold (extraoral and intraoral: p < 0.001) also increased. QualST showed extraoral pinprick (p = 0.032) and intraoral pinprick (p = 0.000), cold (p = 0.000) and touch (p = 0.002) stimuli abnormalities overtime. ConclusionsSomatosensory alterations after implant surgery were detected in both quantitative and qualitative sensory assessments, but rapidly decreased during the first follow-ups, and then continuously until 1-year. Clinical SignificanceThis study provides clinical and controlled evidence on the real effect of the somatosensory alterations overtime, leading to a better understanding of neurosensory behaviour after single-tooth dental implant rehabilitation.

Daphnetin Ameliorates Neuropathic Pain via Regulation of Microglial Responses and Glycerophospholipid Metabolism in the Spinal Cord.

Neuropathic pain (NP) is a common type of chronic pain caused by a lesion or disease of the somatosensory nervous system. This condition imposes a considerable economic burden on society and patients. Daphnetin (DAP) is a natural product isolated from a Chinese medicinal herb with various pharmacological activities, such as anti-inflammatory and analgesic properties. However, the underlying mechanisms of these effects are not fully understood. In the present study, we aimed to investigate DAP's anti-inflammatory and analgesic effects and explore the underlying mechanisms of action. The NP model was established as chronic constrictive injury (CCI) of the sciatic nerve, and pain sensitivity was evaluated by measuring the mechanical withdrawal threshold (MWT) and thermal withdrawal threshold (TWT). The activation of microglia in the spinal dorsal horn was measured via immunofluorescence staining. Protein levels were measured using a western blot assay. Using a mass-spectrometry proteomics platform and an LC-MS/MS-based metabolomics platform, proteins and metabolites in spinal cord tissues were extracted and analyzed. DAP treatment ameliorated the MWT and TWT in CCI rats. The expression of IL-1β, IL-6, and TNF-α was inhibited by DAP treatment in the spinal cords of CCI rats. Moreover, the activation of microglia was suppressed after DAP treatment. The elevation in the levels of P2X4, IRF8, IRF5, BDNF, and p-P38/P38 in the spinal cord caused by CCI was inhibited by DAP. Proteomics and metabolomics results indicated that DAP ameliorated the imbalance of glycerophospholipid metabolism in the spinal cords of CCI rats. DAP can potentially ameliorate NP by regulating microglial responses and glycerophospholipid metabolism in the CCI model. This study provides a pharmacological justification for using DAP in the management of NP.

Understanding Outdoor Cold Stress and Thermal Perception of the Elderly in Severely Cold Climates: A Case Study in Harbin

This study collected data through microclimate monitoring, surface temperature measurements, and questionnaire surveys, and used indicators, such as the universal thermal climate index (UTCI), surface temperature (Ts), and wind chill temperature (tWC), to determine the thermal comfort threshold of the elderly in severely cold climates and evaluate their cold stress. The results indicated that (1) the neutral UTCI (NUTCI) for elderly individuals in winter was 13.3 °C, and the NUTCI range was from 1.4 to 25.2 °C; (2) the intensity of elderly individuals’ physical activity affected the magnitude of risk of whole-body cooling, with duration-limited exposures corresponding to 0.5, 3.3, and over 8 h for light, moderate, and vigorous activity levels, respectively; (3) the tWC in all four spaces was below −10 °C, potentially inducing discomfort or even frostbite in the elderly; (4) for a 10 s touch, the maximum Ts (−17.2 °C) of stone was lower than the numbness threshold (−15.0 °C), while that (−15.1 °C) of steel materials remained below the frostbite threshold (−13 °C), posing risks for the elderly during physical activity. This study’s results will provide valuable insights and theoretical references for the landscape design of urban park activity spaces for elderly individuals in cold climate regions.