Multiple ratiometric nanothermometry using semiconductor BiFeO3 nanowires and quantitative validation of thermal sensitivity

Here, we report a very sensitive, non-contact, ratio-metric, and robust luminescence-based temperature sensing using a combination of conventional photoluminescence (PL) and negative thermal quenching (NTQ) mechanisms of semiconductor BiFeO3 (BFO) nanowires. Using this approach, we have demonstrated the absolute thermal sensitivity of ~ 10 mK−1 over the 300–438 K temperature range and the relative sensitivity of 0.75% K−1 at 300 K. Further, we have validated thermal sensitivity of BFO nanowires quantitatively using linear regression and analytical hierarchy process (AHP) and found close match with the experimental results. These results indicated that BFO nanowires are excellent candidates for developing high‐performance luminescence-based temperature sensors. Graphical abstract

Temperature sensitivity of Notch signaling underlies species-specific developmental plasticity and robustness in amniote brains

Ambient temperature significantly affects developmental timing in animals. The temperature sensitivity of embryogenesis is generally believed to be a consequence of the thermal dependency of cellular metabolism. However, the adaptive molecular mechanisms that respond to variations in temperature remain unclear. Here, we report species-specific thermal sensitivity of Notch signaling in the developing amniote brain. Transient hypothermic conditions increase canonical Notch activity and reduce neurogenesis in chick neural progenitors. Increased biosynthesis of phosphatidylethanolamine, a major glycerophospholipid components of the plasma membrane, mediates hypothermia-induced Notch activation. Furthermore, the species-specific thermal dependency of Notch signaling is associated with developmental robustness to altered Notch signaling. Our results reveal unique regulatory mechanisms for temperature-dependent neurogenic potentials that underlie developmental and evolutionary adaptations to a range of ambient temperatures in amniotes.

Understanding Occupants’ Thermal Sensitivity According to Solar Radiation in an Office Building with Glass Curtain Wall Structure

The thermal comfort of occupants in the increasing number of modern buildings with glass curtain wall structures is of significant research interest. As the thermal sensitivity of building occupants varies with building features, situational factors, and the human body’s thermal balance, it is necessary to derive the comfort temperature based on field research, which was conducted in this study in a South Korean office building with a glass curtain wall structure. The influence of solar radiation on the indoor thermal environment and thermal comfort obtained by measurements and occupant questionnaires was analyzed using cumulative graphs and a sensitivity analysis. The observed changes in operative temperature over time confirmed that occupant comfort was significantly affected by the radiant temperature. Based on this result, two groups (Group A near the windows and Group B near the interior corridor) were defined for analysis. Owing to the influx of solar radiation, Group A was more sensitive to changes in the thermal environment (0.67/°C) than Group B (0.49/°C), and the derived comfort temperature for each group differed from the set temperature by approximately ±2 °C. Thus, it was confirmed that the solar radiation introduced through a glass curtain wall building has a direct impact on the indoor thermal environment and occupant comfort according to location.

Antinociceptive Investigations of Niranthin in Complete Freund’s Adjuvant-induced Chronic Pain in Mice

The main objectives of the present work are to determine the clinical effect of niranthin on visceral or somatic inflammatory pain. The study was performed to determine the effects of niranthin on visceral or somatic inflammatory hypersensitivity of adult Swiss albino mice by using complete Freund’s adjuvant (CFA) induced pain model. The effect of CFA injection was determined after 24 hours of injection by using an aesthesiometer such as Von Frey filaments to evaluate tactile acetone-evoked cooling and thermal sensitivity. We used a digital Plethysmometer to measure paw edema. Single dose of niranthin intraperitoneal injection (5 & 10 mg/kg) was injected into mice having CFA-induced mechanical hypersensitivity and after 30 minutes of administration, reduced mechanical hypersensitivity was observed. In addition, niranthin also reduced acetone-evoked hypersensitivity within 4 hours. Compared to DMSO, niranthin was most highly active to reduce CFA-induced paw edema. To reduce mechanical hypersensitivity, multiple doses of niranthin (bis in die (b.i.d.)) from 1st - 5th day and b.i.d. day 9th and 10th) were given and remarkable results were observed such as did not cause tolerance in multiple dosing and significantly reduced in CFA induced hypersensitivity. This work reported niranthin having antinociceptive activity and indicated that niranthin is conventionally active in the management of persistent pain.

Design of athermalized mounting structure for the sub-aperture primary mirror of a synthetic aperture telescope

The imaging quality of the synthetic aperture system is sensitive to the positioning accuracy of the sub-aperture primary mirror. A novel flexible mounting structure of bimetallic material is proposed for the athermalization of the sub-aperture primary mirror of the Fizeau Synthetic Aperture Telescope – which is composed of seven sub-aperture. The axial position accuracy of the sub-aperture primary mirror must be less than 5 µm under 10°C temperature rise to meet the requirements of the optical system. Firstly, a single mounting unit is analyzed theoretically, and the initial parameters are determined. The conceptual design of the mounting structure is carried out by using initial parameters. The orthogonal optimization algorithm and range analysis are used to optimize the structural parameters. The finite element model of the flexible mounting structure is established and the coupled thermal-mechanical simulation analysis is performed. Then the thermal sensitivity test of the sub-aperture primary mirror mounting structure was carried out. Under the effect of a temperature rise of 10°C, the axial displacement of the sub-aperture primary mirror mounting surface is less than 3 µm. Finally, the synthetic aperture system is assembled, and the optical test verifies that the synthetic aperture system has good imaging capabilities.

Design and Simulation of Waveguide Bragg Grating based Temperature Sensor in COMSOL

With the advancements in the domain of photonics and optical sensors, Fibre Bragg Grating (FBG) sensors, owing to their increased advantages, have been researched widely and have proved to be useful in sensing applications. Moreover, the advent of Photonic Integrated Circuits (PICs) demands the incorporation of optical sensing in waveguides, which can be integrated on silicon photonic chips. In this paper, the design of a sub-micron range Waveguide Bragg Grating (WBG) based temperature sensor with high peak reflectivity and thermal sensitivity is proposed. The flexibility of COMSOL Multiphysics software is explored to simulate the sensor and the results are verified with the analytical values calculated using MATLAB. The simulation is carried out for the proposed design having 16000 gratings and a corresponding peak reflectivity of 0.953 is obtained. A thermal sensitivity of 80 pm/K is achieved, which is approximately eight times better than that of FBG based sensor.

Thermal sensitivity and seasonal change in the gut microbiome of a desert ant, Cephalotes rohweri

Microorganisms within ectotherms must withstand the variable body temperatures of their hosts. Shifts in host body temperature resulting from climate change have the potential to shape ectotherm microbiome composition. Microbiome compositional changes occurring in response to temperature in nature have not been frequently examined, restricting our ability to predict microbe-mediated ectotherm responses to climate change. In a set of field-based observations, we characterized gut bacterial communities and thermal exposure across a population of desert arboreal ants (Cephalotes rohweri). In a paired growth chamber experiment, we exposed ant colonies to variable temperature regimes differing by 5 C for three months. We found that the abundance and composition of ant-associated bacteria were sensitive to elevated temperatures in both field and laboratory experiments. We observed a subset of taxa that responded similarly to temperature in the experimental and observational study, suggesting a role of seasonal temperature and local temperature differences amongst nests in shaping microbiomes within the ant population. Bacterial mutualists in the genus Cephalotococcus (Opitutales: Opitutaceae) were especially sensitive to change in temperature - decreasing in abundance in naturally warm summer nests and warm growth chambers. We also report the discovery of a member of the Candidate Phlya Radiation (Phylum: Gracilibacteria), a suspected epibiont, found in low abundance within the guts of this ant species.

ANALYSIS OF THERMAL EFFECTS WITH MULTI-FOCI STRUCTURING

The possibility of a thermal imaging technique for studying the setting of composite materials in the light of the paradigm of multifocal structure formation is analyzed. Since thermal violated observations are characterized by a high thermal sensitivity to temperature gradients up to hundredths of degrees, they make it possible to distinguish the temperature differences arising in the adjacent sections of the hardening binding. A technique for obtaining thermal images (thermograms) of a hardening composite binder is implemented. A series of thermograms of setting processes was obtained, for two of them a quantitative study was carried out, including the temperature gauge and the construction of several types of graphic mappings of the obtained patterns ‒ the normalized frequency of the distribution of the area of the binder for those temperatures and two types of densitograms ‒ radial and circular, allowing to visualize the structure of thermal foci arising in a binder. The hardening of binding materials is considered as a multistage exothermic process, in which hydration processes is accompanied by heating. The speed of heterogeneous processes associated with hydration depends, in turn, on the characteristics of the forming structure of binding materials. The observed thermal processes are considered as an indirect response, "shadow" of structure formation processes. The information consisting in this indirect response, however, is enough to make a number of conclusions on the nature of the emerging structure. The study revealed a high probability of the formation of foci near the macroscopic boundaries of the section (walls and bottom of the form), inconsistency of the structural processes, the occurrence of diverse foci of structure formation corresponding to temperature foci. The interpretation of the data obtained is the conclusion about formation of the regions of high plastic deformations near the boundaries of the contact of the foci. This regions are considered as a cluster of microscopic boundaries of the section, cracks and pores, which give rise to the structure of the destruction of the hardened material. The emergence of such areas is associated with nonynchronouspassage of structuring in different parts of the binder.

Local-Scale Thermal History Influences Metabolic Response of Marine Invertebrates To Warming

As climate change continues, anticipating species’ responses to rising temperatures, requires an understanding of the relationship between metabolic rate and thermal sensitivity, which itself may vary over space and time. We measured metabolic rates of three representative marine invertebrate species (hermit crabs Pagurus hirsutiusculus, periwinkle snails Littorina sitkana, and mussels Mytilus trossulus) and evaluated the relationship between thermal sensitivity (Q10) and thermal history. We tested the hypothesis that thermal history drives thermal sensitivity and quantified how this relationship differs over time (short-term to seasonal time scales) and between species. Organisms were collected from tide pools in Sitka, Alaska where we also recorded temperatures to characterize thermal history prior to metabolic rate assays. Using respirometry, we estimated mass-specific oxygen consumption (MO2) at ambient and increased temperatures for one individual per species per tide pool across three seasons. We evaluated relationships between thermal sensitivity and pool temperatures for time periods ranging from 1 day to 3 months prior to collection. For all species, thermal sensitivity was related to thermal history for the shorter time periods (1 day to 1 week). However, the direction of the relationships and most important thermal parameters (i.e., maximum, mean, or range) differed between species and seasons. We found that on average, P. hirsutiusculus and L. sitkana were more thermally sensitive than M. trossulus. These findings show that variability in thermal history over small spatial scales influences individuals’ metabolic response to warming and may be indicative of these species’ ability to acclimate to future climate change.