Metabolic consequences of obesity and type 2 diabetes: Balancing genes and environment for personalized care.

The prevalence of type 2 diabetes and obesity has risen dramatically for decades and is expected to rise further, secondary to the growing aging, sedentary population. The strain on global health care is projected to be colossal. This review explores the latest work and emerging ideas related to genetic and environmental factors influencing metabolism. Translational research and clinical applications, including the impact of the COVID-19 pandemic, are highlighted. Looking forward, strategies to personalize all aspects of prevention, management and care are necessary to improve health outcomes and reduce the impact of these metabolic diseases.

Peeking under the hood of early embryogenesis: Using tools and synthetic biology to understand native control systems and sculpt tissues.

Early embryogenesis requires rapid division of pluripotent blastomeres, regulated genome activation, precise spatiotemporal signaling to pattern cell fate, and morphogenesis to shape primitive tissue architectures. The complexity of this process has inspired researchers to move beyond simple genetic perturbation into engineered devices and synthetic biology tools to permit temporal and spatial manipulation of the control systems guiding development. By precise alteration of embryo organization, it is now possible to advance beyond basic analytical strategies and directly test the sufficiency of models for developmental regulation. Separately, advances in micropatterning and embryoid culture have facilitated the bottom-up construction of complex embryo tissues allowing ex vivo systems to recapitulate even later stages of development. Embryos fertilized and grown ex vivo offer an excellent opportunity to exogenously perturb fundamental pathways governing embryogenesis. Here we review the technologies developed to thermally modulate the embryo cell cycle, and optically regulate morphogen and signaling pathways in space and time, specifically in the blastula embryo. Additionally, we highlight recent advances in cell patterning in two and three dimensions that have helped reveal the self-organizing properties and gene regulatory networks guiding early embryo organization.

Dual-Interface Solar Evaporator with Highly-Efficient Thermal Regulation via Suspended Multilayer Design.

Facing the increasing global shortage of freshwater resources, this study presents a suspended multilayer evaporator (SMLE), designed to tackle the principal issues plaguing current solar-driven interfacial evaporation technologies, specifically, substantial thermal losses and limited water production. This approach, through the implementation of a multilayer structural design, enables superior thermal regulation throughout the evaporation process. This evaporator consists of a radiation damping layer, a photothermal conversion layer, and a bottom layer that leverages radiation, wherein the bottom layer exhibits a notable infrared emissivity. The distinctive feature of the design effectively reduces radiative heat loss and facilitates dual-interface evaporation by heating the water surface through mid-infrared radiation. The refined design leads to a notable evaporation rate of 2.83 kg m-2 h-1. Numerical simulations and practical performance evaluations validate the effectiveness of the multilayer evaporator in actual use scenarios. This energy-recycling and dual-interface evaporation multilayered approach propels the design of high-efficiency solar-driven interfacial evaporators forward, presenting new insights into developing effective water-energy transformation systems.

Determinants of thermal homeostasis in the preimplantation embryo: a role for the embryo's central heating system?

A number of factors may impinge on thermal homeostasis in the early embryo. The most obvious is the ambient temperature in which development occurs. Physiologically, the temperature in the lumen of the female tract is typically lower than the core body temperature, yet rises at ovulation in the human, while in an IVF setting, embryos are usually maintained at core body temperature. However, internal cellular developmental processes may modulate thermal control within the embryo itself, especially those occurring in the mitochondria which generate intracellular heat through proton leak and provide the embryo with its own 'central heating system'. Moreover, mitochondrial movements may serve to buffer high local intracellular temperatures. It is also notable that the preimplantation stages of development would generate proportionally little heat within their mitochondria until the blastocyst stage as mitochondrial metabolism is comparatively low during the cleavage stages. Despite these data, the specific notion of thermal control of preimplantation development has received remarkably scant consideration. This opinion paper illustrates the lack of reliable quantitative data on these markers and identifies a major research agenda which needs to be addressed with urgency in view of laboratory conditions in which embryos are maintained as well as climate change-derived heat stress which has a negative effect on numerous clinical markers of early human embryo development.

Phase-Engineered VO2 Metal Nanofiber Enables a Metal-Insulator Transition for Bidirectional Thermal Reallocation.

Phase change materials (PCMs) are appealing for their fascinating capability of thermal reallocation, assisting widely in many areas of human productivity and life. However, it has remained a significant challenge to attain shape stability, temperature resistance, and microscale continuity in PCMs while maintaining sufficient phase change performance. Here we report a sol epitaxial fabrication strategy to create metal-insulator transition nanofibers (MIT-NFs) composed of monoclinic vanadium dioxide. The MIT-NFs are further assembled into self-standing two-dimensional membranes and three-dimensional aerogels with structural robustness. The resulting series of metal-insulator transition materials exhibits the integrated features of solid-solid phase change properties, shape stability, and thermal reallocation properties. The integral ceramic characteristic also provides the MIT-NFs with surface stiffness (54 GPa), temperature resistance (-196° to 330 °C), and thermal insulator properties. The successful fabrication of these captivating MIT materials may provide new perspectives for next-generation, shape-stable, and self-standing PCMs.

Preparation and Thermal Properties of Magnetic PW@CaCO3@Fe3O4 Phase-Change Microcapsules and Their Application to Textile Fabrics.

Multifunctional thermal regulation materials with good thermal properties, efficient magnetic performance, and satisfactory interface bonding on fabrics are highly desirable for protective fabrics, building winter protection materials, medical thermal regulation materials, and special-environment work clothing. Herein, a new class of magnetic phase-change PW@CaCO3@Fe3O4 microcapsules was successfully produced by controlling the content of magnetic Fe3O4 through a self-assembly method. The microstructure, chemical composition, phase-change behavior, and magnetic properties of the products were sequentially characterized and analyzed. The findings revealed that the obtained microcapsules possessed regular spherical structure with uniform size and excellent thermal properties. Furthermore, PW@CaCO3 with Fe3O4 (i.e., 8% mass fraction) showed the highest thermal regulation and magnetic properties and reached an enthalpy value of 94.25 J·g-1, which is clearly superior to the value of 77.51 J·g-1 for PW@CaCO3 microcapsules. At the same time, the encapsulation efficiency of 38.7% and saturation magnetization of 2.50 emu·g-1 were the best among the four given samples. Therefore, the good paramagnetic feature had a significant synergistic effect on the thermal properties of the PW@CaCO3 microcapsules under study. More importantly, multifunctional fabrics loaded with PW@CaCO3@Fe3O4 microcapsules still showed an enthalpy value of 25.81 J·g-1 after several washes and have the potential to be used widely in the field of temperature control. The thermal regulation fabrics in this study exhibited excellent thermal properties and fastness, which contribute to their practical applications in advancing multifunctional textiles and high-technology modern fabrics.

The involvement of CiaR and the CiaR-regulated serine protease HtrA in thermal adaptation of Streptococcus pneumoniae.

The in vivo temperature can vary according to the host tissue and the response to infection. Streptococcus pneumoniae has evolved mechanisms to survive these temperature differences, but neither the consequences of different temperatures for pneumococcal phenotype nor the genetic basis of thermal adaptation are known in detail. In our previous study [16], we found that CiaR, which is a part of two-component regulatory system CiaRH, as well as 17 genes known to be controlled by CiaRH, were identified to be differentially expressed with temperature. One of the CiaRH-regulated genes shown to be differentially regulated by temperature is for the high-temperature requirement protein (HtrA), coded by SPD_2068 (htrA). In this study, we hypothesized that the CiaRH system plays an important role in pneumococcal thermal adaptation through its control over htrA. This hypothesis was evaluated by testing strains mutated or overexpressing ciaR and/or htrA, in in vitro and in vivo assays. The results showed that in the absence of ciaR, the growth, haemolytic activity, amount of capsule and biofilm formation were considerably diminished at 40 °C only, while the cell size and virulence were affected at both 34 and 40 °C. The overexpression of htrA in the ∆ciaR background reconstituted the growth at all temperatures, and the haemolytic activity, biofilm formation and virulence of ∆ciaR partially at 40 °C. We also showed that overexpression of htrA in the wild-type promoted pneumococcal virulence at 40 °C, while the increase of capsule was observed at 34 °C, suggesting that the role of htrA changes at different temperatures. Our data suggest that CiaR and HtrA play an important role in pneumococcal thermal adaptation.

Prompted hands-free drinking improves simulated race car driving in a hot environment.

Race car drivers are often hypohydrated during a race. The FluidLogic drink system is a hands-free, prompted drinking system that is hypothesized to increase the likeliness of drivers' consuming fluids and thereby mitigating hypohydration. To test the hypothesis, 20 elite professional race car drivers participated in a 2-day cross-over study in which they drove on a race simulator in an environmental chamber that was heated to regulation cockpit temperature (38°C). Drivers used either the FluidLogic drink system or a standard in-car water bottle system (Control) on one of each testing day. The results indicated that there was consistent fluid consumption with the FluidLogic system, while the Control condition elicited fluid consumption in bolus doses. The Control condition was associated with moderate (0.5%) increased core body temperature (P < 0.05) and substantial (3.3%) increased urine-specific gravity (P < 0.001) as compared to the FluidLogic condition. Driving performance metrics indicated that lap times during the Control Condition were 5.1 ± 1.4 (4.1%) seconds slower (P < 0.05) than the FluidLogic Condition, due to driving errors that occurred in the high-speed corners. Based on these results, prompted hands-free drinking can mitigate hypohydration and performance loss in automobile racing drivers.

An Advanced Internet of Things System for Heatstroke Prevention with a Noninvasive Dual-Heat-Flux Thermometer.

Heatstroke is a concern during sudden heat waves. We designed and prototyped an Internet of Things system for heatstroke prevention, which integrates physiological information, including deep body temperature (DBT), based on the dual-heat-flux method. A dual-heat-flux thermometer developed to monitor DBT in real-time was also evaluated. Real-time readings from the thermometer are stored on a cloud platform and processed by a decision rule, which can alert the user to heatstroke. Although the validation of the system is ongoing, its feasibility is demonstrated in a preliminary experiment.

Selective Magnetic Nanoheating: Combining Iron Oxide Nanoparticles for Multi-Hot-Spot Induction and Sequential Regulation.

The contactless heating capacity of magnetic nanoparticles (MNPs) has been exploited in fields such as hyperthermia cancer therapy, catalysis, and enzymatic thermal regulation. Herein, we propose an advanced technology to generate multiple local temperatures in a single-pot reactor by exploiting the unique nanoheating features of iron oxide MNPs exposed to alternating magnetic fields (AMFs). The heating power of the MNPs depends on their magnetic features but also on the intensity and frequency conditions of the AMF. Using a mixture of diluted colloids of MNPs we were able to generate a multi-hot-spot reactor in which each population of MNPs can be selectively activated by adjusting the AMF conditions. The maximum temperature reached at the surface of each MNP was registered using independent fluorescent thermometers that mimic the molecular link between enzymes and MNPs. This technology paves the path for the implementation of a selective regulation of multienzymatic reactions.

A physiological model of the inflammatory-thermal-pain-cardiovascular interactions during an endotoxin challenge.

KEY POINTS: Inflammation in response to bacterial endotoxin challenge impacts physiological functions, including cardiovascular, thermal and pain dynamics, although the mechanisms are poorly understood. We develop an innovative mathematical model incorporating interaction pathways between inflammation and physiological processes observed in response to an endotoxin challenge. We calibrate the model to individual data from 20 subjects in an experimental study of the human inflammatory and physiological responses to endotoxin, and we validate the model against human data from an independent study. Using the model to simulate patient responses to different treatment modalities reveals that a multimodal treatment combining several therapeutic strategies gives the best recovery outcome. ABSTRACT: Uncontrolled, excessive production of pro-inflammatory mediators from immune cells and traumatized tissues can cause systemic inflammatory conditions such as sepsis, one of the ten leading causes of death in the USA, and one of the three leading causes of death in the intensive care unit. Understanding how inflammation affects physiological processes, including cardiovascular, thermal and pain dynamics, can improve a patient's chance of recovery after an inflammatory event caused by surgery or a severe infection. Although the effects of the autonomic response on the inflammatory system are well-known, knowledge about the reverse interaction is lacking. The present study develops a mathematical model analyzing the inflammatory system's interactions with thermal, pain and cardiovascular dynamics in response to a bacterial endotoxin challenge. We calibrate the model with individual data from an experimental study of the inflammatory and physiological responses to a one-time administration of endotoxin in 20 healthy young men and validate it against data from an independent endotoxin study. We use simulation to explore how various treatments help patients exposed to a sustained pathological input. The treatments explored include bacterial endotoxin adsorption, antipyretics and vasopressors, as well as combinations of these. Our findings suggest that the most favourable recovery outcome is achieved by a multimodal strategy, combining all three interventions to simultaneously remove endotoxin from the body and alleviate symptoms caused by the immune system as it fights the infection.

A unit-cell model for thermal regulation of degradation of organics in solid waste.

It is a well appreciated fact that temperature is one of the key factors influencing the degradation of organics. Heat exchangers are a viable option that can be used to adjust the temperature in solid waste to an extent most suitable for waste degradation. This paper focuses on an experimental and theoretical investigation of the feasibility of using a water-circulating heat exchanger for thermal regulation of waste degradation. A cylindrical bioreactor with a central pipe connected to a water circulation system is devised and instrumented. The changes in temperature and gas production were monitored during the degradation of the organic component of the waste. Test results with and without thermal regulation are analyzed and compared. In addition, an analytical model is proposed to simulate the symmetrical heat transport behavior subjected to heat exchange. Heat generation due to the degradation of organics is taken into account. There was a good correlation between the analytical model prediction and the experimental data obtained from the laboratory test and field monitoring.

Raspberry-Shaped Thermochromic Energy Storage Nanocapsule with Tunable Sunlight Absorption Based on Color Change for Temperature Regulation.

A novel raspberry-shaped thermochromic energy storage nanocapsule (RTESN) is successfully designed and fabricated with switchable sunlight absorption capacity based on color change for temperature regulation. The RTESN is developed by grafting amino-modified silica shell thermochromic nanoparticles (amino-TLD@SiO2 ) on the surface of epoxy-functionalized energy storage nanocapsules (paraffin@PSG), with a total particle size about 450 nm. RTESN exhibits a deep color under low temperatures, which can absorb sunlight for heating. During the continuous thermal energy supply, paraffin@PSG is capable of storing thermal energy owing to its large latent heat capacity of 118.7 J g-1 , thereby maintaining the slow temperature increase. When the temperature is higher than the phase change temperature of paraffin@PSG, the color of amino-TLD@SiO2 turns to white with more reflection of sunlight so that it reduces the absorption of thermal energy and prevents the further increase of temperature. The thermal regulation behavior is confirmed by setting up a wooden house with the surface covered with RTESN. Compared with the blank wooden house, the RTESN covered wooden house (RTESN-H) displays thermal insulation performances during heating and cooling with a maximum temperature difference of 7 °C.

A Smart Epoxy Composite Based on Phase Change Microcapsules: Preparation, Microstructure, Thermal and Dynamic Mechanical Performances.

Microencapsulated phase change materials (MicroPCMs)-incorporated in epoxy composites have drawn increasing interest due to their promising application potential in the fields of thermal energy storage and temperature regulation. However, the study on the effect of MicroPCMs on their microstructure, thermal and viscoelastic properties is quite limited. Herein, a new type of smart epoxy composite incorporated with polyurea (PU)-shelled MicroPCMs was fabricated via solution casting method. Field emission-scanning electron microscope (FE-SEM) images revealed that the MicroPCMs were uniformly distributed in the epoxy matrix. The thermal stabilities, conductivities, phase change properties, and dynamic mechanical behaviors of the composite were studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), thermal constant analyzer and infrared thermography. The results suggested that the heat storage ability of the composites was improved by increasing the MicroPCMs content. The thermal stability of MicroPCMs was found to be enhanced after incorporation into the matrix, and the MicroPCMs-incorporated epoxy composites showed a good thermal cycling reliability. Moreover, the incorporation of MicroPCMs reduced the composites' storage modulus but increased the glass transition temperature (Tg) as a result of their restriction to the chain motion of epoxy resin. Besides, a less marked heating effect for the composite was explored through infrared thermography analysis, demonstrating the good prospect for temperature regulation application.

Alkylated Meso-Macroporous Metal-Organic Framework Hollow Tubes as Nanocontainers of Octadecane for Energy Storage and Thermal Regulation.

Alkylated meso-macroporous Cr-MIL-101 hollow tubes (ACHT) are synthesized through the coordination of Cr3+ with alkylated bridged ligands. The alkylated ligands work as both bridging ligands and structure-directing agents, which presents a new strategy for synthesizing meso-macroporous metal-organic frameworks (MOFs). This is the first example of 1D meso-macroporous MOF hollow tubes with large pore diameter (5-136 nm). Furthermore, the octadecane@ACHT form-stable phase change materials (FSPCMs) are prepared using ACHT as nanocontainers for octadecane. The nanocavity of ACHT possesses enough storage space for octadecane, and the large number of alkyl chains on the ACHT framework induces octadecane molecules to crystallize from α- to ß-crystals. Considering the comfortable phase transition temperature (27.7 °C) and the relatively large thermal storage capacity (187 J g-1 ), the octadecane@ACHT FSPCMs can be used in interior wall of building to improve the indoor thermal comfort or in the field of thermal-regulated textiles and clothing.

Temporal sequencing of brain activations during naturally occurring thermoregulatory events.

Thermoregulatory events are associated with activity in the constituents of the spinothalamic tract. Whereas studies have assessed activity within constituents of this pathway, in vivo functional magnetic resonance imaging (fMRI) studies have not determined if neuronal activity in the constituents of the tract is temporally ordered. Ordered activity would be expected in naturally occurring thermal events, such as menopausal hot flashes (HFs), which occur in physiological sequence. The origins of HFs may lie in brainstem structures where neuronal activity may occur earlier than in interoceptive centers, such as the insula and the prefrontal cortex. To study such time ordering, we conducted blood oxygen level-dependent-based fMRI in a group of postmenopausal women to measure neuronal activity in the brainstem, insula, and prefrontal cortex around the onset of an HF (detected using synchronously acquired skin conductance responses). Rise in brainstem activity occurred before the detectable onset of an HF. Activity in the insular and prefrontal trailed that in the brainstem, appearing following the onset of the HF. Additional activations associated with HF's were observed in the anterior cingulate cortex and the basal ganglia. Pre-HF brainstem responses may reflect the functional origins of internal thermoregulatory events. By comparison insular, prefrontal and striatal activity may be associated with the phenomenological correlates of HFs.

Seeing the body produces limb-specific modulation of skin temperature.

Vision of the body, even when non-informative about stimulation, affects somatosensory processing. We investigated whether seeing the body also modulates autonomic control in the periphery by measuring skin temperature while manipulating vision. Using a mirror box, the skin temperature was measured from left hand dorsum while participants: (i) had the illusion of seeing their left hand, (ii) had the illusion of seeing an object at the same location or (iii) looked directly at their contralateral right hand. Skin temperature of the left hand increased when participants had the illusion of directly seeing that hand but not in the other two view conditions. In experiment 2, participants viewed directly their left or right hand, or the box while we recorded both hand dorsum temperatures. Temperature increased in the viewed hand but not the contralateral hand. These results show that seeing the body produces limb-specific modulation of thermal regulation.

Sustainable Thermal Regulation of Electronics via Mitigated Supercooling of Porous Gallium-Based Phase Change Materials.

Gallium liquid metal is one of the promising phase change materials for passive thermal management of electronics due to their high thermal conductivity and latent heat per volume. However, it suffers from severe supercooling, in which molten gallium does not return to solid due to the lack of nucleation. It may require 28.2 °C lower temperature than the original freezing point to address supercooling, leading to unstable thermal regulation performance along fluctuations of cooling condition. Here, gallium is infused into porous copper in an oxide-free environment, forming intermetallic compound impurities at the interfaces to reduce the activation energy for heterogeneous nucleation. The porous-shaped gallium provides ≈63% smaller supercooling than that of the bulk type due to large specific surface area (≈9,070 cm2 per cm3) and high wetting characteristics (≈16° of contact angle) on CuGa2 intermetallic layer. During repetitive heating-cooling cycles, porous-shaped gallium consistently shows propagation of crystallization at even near room temperature (≈25 °C) while maintaining stable performance as thermal buffer, whereas droplet-shaped gallium is gradually degraded due to partial-supercooled state. The findings will improve the responsive thermal regulation performance to relieve a rapid increase in temperature of semiconductors/batteries, and also have a potential for energy storage applications.

Thermal relations in sled dogs before and after exercise.

Regulation of internal body temperature (Tb), or thermoregulation, is an evolutionarily conserved trait that places demand on basal metabolic rate of endothermic animals. Across species, athletes generate increased quantities of heat in comparison to their nonathletic counterparts and, therefore, must mediate physiological unbalance by upregulating the effectiveness of their heat dissipation abilities. Canine athletes are no exception to this phenomenon, however, with literature denoting body temperatures lower than nonathletic canines, it is clear they must possess adaptations to mitigate this demand. With VO2 max measurements of more than 200 mL/kg/min in sled dogs with mild training to 300 mL/kg/min in highly trained animals, sled dogs are a prime example of athleticism in canines. Seeking to determine correlations between Tear and body mass, morphology, and age of canine athletes, core body temperature (Tb) was measured with an instant ear thermometer, using Tear as a correlate before and after a 2-mile run. In addition, we employed thermal imaging analysis to capture body-wide heat dissipation patterns in sled dogs, and focused on thermal variation of mouth (Tmouth), nose (Tnose), and eyes (Teye). Furthermore, we looked at correlations between thermal variability across these four tissues and head morphology of each dog. Tear was consistently the highest temperature across all tissues measured, with a 1.5°C increase between pre- to postexercise (p < 0.001). Thermal imaging revealed significant positive correlations between Tmouth and body mass 15 min postexercise (p = 0.0023) as well as significantly negative correlations between Tnose and body mass at before exercise (p = 0.0468), Teye and nose length after run (p = 0.0076), and Tmouth and nose length after run (p = 0.0110). As body temperature rises during exercise, it becomes increasingly important to regulate blood flow throughout the body to supply working tissues with oxygen. This demand is offset by the role of the snout in evaporative cooling through panting, functioning as a prime location for heat dissipation and therefore maintaining significant relationships with many other vascularized tissues.

Thermal self-crosslink after etching for regulated preparation of Ti3C2 type MXene membrane and its preliminary gas separation.

We present an innovative methodology for the synthesis of MXene membranes through a dual-stage process involving etching and subsequent thermal self-crosslinking. A molar ratio of 1 (Al3+):9 (F-) using HCl/LiF was employed to convert raw Ti3AlC2 (MAX phase) into MXene within 48 h at 40 °C. This procedure predominantly yielded monolayers distinguished by diameters exceeding 500 nm, elevated crystallinity and a high overall yield. Advanced characterization techniques, including FESEM, TEM, HRTEM, AFM, XPS, and FTIR, were utilized. Instrumental analysis confirmed the formation of MXene exhibiting a single-flake morphology with diameters exceeding 500 nm. These monolayers were intact and continuous, with smooth peripheries and a uniform thickness of 2.1 nm. The surfaces were predominantly composed of carbon (C), oxygen (O), and titanium (Ti) atoms, interconnected by chemical bonds such as C-Ti-O, C-Ti-OH, C-C, C-O, and Ti-O. In the subsequent phase, vacuum filtration facilitated the assembly of a self-supporting MXene membrane. Thermal treatment at 170 °C for 30 h resulted in the reinforcement of C-Ti-O bonds within the nanosheets, increasing their prevalence to 43.14 % and 19.47 %, respectively. This thermal regulation reduced the interlayer d-spacing from 4.33 to 3.54 Å, which significantly improved the gas separation efficiency beyond the Knudsen diffusion limit, as demonstrated by the αH2/CF4 value exceeding 23.0.