Thermal Stimulation Research Articles

Sustainability of CO2 replacement processes in marine hydrate reservoirs: Factors causing changes on mechanical properties of Gas-Hydrate after CO2/CH4 exchange

The energy content of Gas Hydrated in form of natural gas is approximately twice with respect to the total energy still producible from all the known conventional energy sources. To reduce the risk induced by exploitation of hydrate reservoirs a good knowledge of the mechanical properties is crucial. Here we simulate CH4 replacement with CO2 and then we analyze the mechanical properties of replaced hydrates through porosity, Vp and Vs measurements. Replacement tests with CO2 have been performed by depressurization and thermal stimulation. Both procedures result in a final CH4/CO2 concentration of ∼30/70%. We then measured the petrophysical properties of pure CO2 and CH4/CO2 hydrates hosted in synthetic (Glass beads -GB) and natural sand (Iceland Sand-IS). Porosity and velocity within the same hosting sediments, show a clear inverse relation for the sub-angular and poorly sorted IS being this less evident for the spherical and highly sorted GB sands. CO2 replacement increases Vp and dynamic Young’s modulus for GB samples whilst IS are less influenced by the presence of CO2. These results demonstrate that reservoir sediments severely affect the mechanical properties of hydrates and thus their characteristics must be taken in account for safety well and reservoir management.

Thermal testing of corundum ceramic plates

A review of the methods of production of corundum ceramics with specified characteristics is carried out and possible causes of hidden defects are indicated. Ceramic samples for research were obtained by the method of slip casting and their physical properties were determined. The possibility of diagnosing the integrity of corundum ceramic plates was investigated by the method of active thermal non-destructive testing. Various testing schemes and sources of thermal stimulation of the studied samples were applied. As a reference method, X-ray inspection was used, which confirmed the characteristics of the defect detected by the thermal method in the control sample.

Reversible Change in Performances of Polymer Networks via Invertible Architecture-Transformation of Cross-Links.

A polymer nanoparticle network using single-chain nanoparticles (SCNPs) as cross-links is designed. The experimental and theoretical study shows that incorporating SCNPs in polymer networks leads to smaller mesh size, faster terminal relaxation time, and reduced fluctuation among cross-links, resulting in a significant increase in shear storage modulus, and enhancement in tensile stress. Notably, the reversible single-chain collapse of SCNPs under thermal stimulation enables the polymer network to undergo coherent changes between two topological states, thereby exhibiting reversible transformations between soft and stiff states. This approach and finding can effectively tailor the mechanical properties of polymer networks, potentially leading to the development of intelligent, responsive materials.

Thermal/UV Respond Polydiacetylene /Ni2+ Thermal Paper with Reusability

AbstractPolydiacetylenes (PDAs) are a family of highly conjugated polymers that generate optical response sensitively if exposed to stimuli, the color would change from blue to red. PDAs with reusability and color reversibility are at the central of current research efforts generously. They enhance the electrostatic interaction between cations and the negatively charged carboxylate head groups to increase the rigidity and decrease the energy barrier by introducing Ni2+ into the side chains of PDAs. The amphiphilic 10,12‐pentacosadiynoic acid (PCDA) molecules with the hydrophilic and hydrophobic group are dispersed into Ni2+ aqueous solution and self‐assembled in situ into nanoparticles. Transferring the solution onto a paper base to yield a precisely controlled thickness of PDAs thermal paper. The thermal paper undergoes UV‐induced topological chemical polymerization and further cross‐linking to form stably blue. Because of the reduced energy barrier, red thermal paper after thermal stimulation can undergo color reduction under UV light irradiation. Increasing the photopolymerization time from 5 s to 600 s leads to the rising of the color change temperature from approximately 76.4 °C to 105.4 °C. The polydiacetylene/Ni2+ (PDA/Ni2+) thermal paper can be available for green printing, thermal history recording, and temperature visualization.

Optical Signals for Quantitative and Qualitative Monitoring of Temperature‐Sensitive Products

AbstractMonitoring the real‐time quality and validity of thermo‐sensitive foods during storage and transportation can be achieved with time‐temperature indicators (TTIs). However, the available TTIs still need to be improved in terms of accuracy, recoverability, environmental tolerance, and quantitative monitoring. Here, a novel TTI based on the optical signals originating from the as‐explored Sr3Y2Ge3O12: Mn2+, Er3+ (SYGO: Mn2+, Er3+) phosphor is developed. Thanks to the fact that the release of the captured carriers is tightly related to the storage time and ambient temperature, distinct optical signals of the as‐obtained TTI under multi‐stimulus (980 nm laser irradiation, thermal stimulation, and mechanical force) can be distinguished to judge the validity of temperature‐sensitive products. This work reveals the promising potential of SYGO: Mn2+, Er3+ phosphors with cryogenic optical storage properties as advanced TTIs, especially for packaged products in cold chain logistics.

Placebo analgesia and nocebo hyperalgesia in patients with Alzheimer disease and healthy participants.

The role of placebo analgesia and nocebo hyperalgesia in patients with Alzheimer disease (AD) is largely unknown, with only few studies in the area. Therefore, this study aims to investigate to which extent placebo analgesia and nocebo hyperalgesia effects are present in patients experiencing mild-to-moderate AD. Twenty-one patients with AD (test population) and 26 healthy participants (HP; design validation) were exposed to thermal pain stimulation on 3 test days: Lidocaine condition (open/hidden lidocaine administration), capsaicin condition (open/hidden capsaicin administration), and natural history (no treatment), in a randomized, within-subject design. Open lidocaine and open capsaicin were accompanied by verbal suggestions for pain relief and pain increase, respectively. Expected pain and actual pain intensity were measured on a numerical rating scale (0-10). Placebo and nocebo effects were calculated as pain differences in open-hidden lidocaine and capsaicin, respectively, controlled for no treatment. Healthy participants obtained a placebo effect ( P = 0.01) and a trend for a nocebo effect ( P = 0.07). Patients with AD did not obtain a placebo effect ( P = 0.44) nor a significant nocebo effect ( P = 0.86). Healthy participants expected lower and higher pain with open vs hidden lidocaine and capsaicin, respectively ( P < 0.001). The same expectation effects were seen in patients with AD (open vs hidden lidocaine, P = 0.008; open vs hidden capsaicin, P < 0.001). With a well-controlled experimental setting, this study suggests that patients with AD may not experience placebo analgesia effects. Nocebo hyperalgesia effects in patients with AD needs further research. These findings may have implications for the conduction of clinical trials and the treatment of patients with AD in clinical practice.

The experimental investigating in water-rock interaction to reduce the thermal cracking threshold temperature of organic-rich shale

Thermal stimulation has excellent potential for enhancing the productivity of organic-rich shale. However, this shale's high thermal cracking threshold temperature (Ttct) results in excessive energy consumption and stringent casing safety requirements. Thus, optimizing thermal stimulation technology and reducing the Ttct is critical for efficient oil and gas production. This study proposes a novel method for quantifying the Ttct by fitting the S-shaped characteristics of the curve using the Sweibull2 model and defining the temperature corresponding to the maximum first-order derivative as the threshold value. Furthermore, we investigate the feasibility of reducing the high Ttct via water-rock interactions. Our findings show that the average Ttct of the anhydrous shale rock samples was 574 ℃, which decreased significantly to 344 ℃ and 336 ℃ for those samples saturated with distilled water and KCl solution, respectively. Persulfate oxidation resulted in noticeable reductions in the shale's Ttct and led to sample deformation and the initiation of large-scale fractures at temperatures below 200 ℃. However, the Ttct did not decrease significantly after acidizing and averaged 545 ℃. In summary, by adjusting the salinity of the fracturing fluid and incorporating suitable additives to match the reservoir’s properties, the effectiveness of heat treatment can be significantly enhanced. These findings present potential opportunities for improving oil and gas recovery while simultaneously reducing the energy consumption associated with thermal stimulation.

Pore-Scale Investigation of Decomposition-Methods-Dependent Fluid Flow Properties in Hydrate-Bearing Sediments

Summary Depressurization (PD) and thermal stimulation (TS) are the primary methods for producing gas from natural gas hydrate (NGH) sediments. Fluid flow properties of the hydrate sediment, such as permeability, are fundamental parameters for simulating both processes. Most of the existing formulated permeability models are based on the numerical or experimental investigation of hydrate morphology evolution without considering the decomposition methods. In this study, we investigate the hydrate-decomposition-methods (PD and TS processes)-dependent fluid flow properties of hydrate sediments, which is achieved by microcomputed tomography (micro-CT) scanning of hydrate morphology evolution during PD- and TS-induced decomposition, as well as pore-scale modeling of fluid flow in the extracted 3D fluid-rock-hydrate images. We find that the decomposition behavior during TS is much more complicated than that during PD. The retardation zone in the PD sample increases the heterogeneity of the pore structure, while the secondary hydrates generated during TS cause even more heterogeneity in the pore space. The better facilitation of the TS method on hydrate split is favorable for the continuity of the gas phase. The pore-scale fluid flow simulation shows that the modified Kozeny-Carman (K-C) model is the best to describe the evolution of the normalized permeability with hydrate saturation during PD. However, a single model is not sufficient to describe the normalized permeability during TS decomposition due to the stronger heterogeneous porous structure reformed by the local accumulation of secondary hydrates. The two-phase flow capability is best at the initial stage of PD decomposition, while the two-phase flow region becomes wider as TS decomposition progresses. These results provide significant references for the simulation of the natural hydrate extraction process using different decomposition methods.

Geomechanical in situ testing of fault reactivation in argillite repositories

Abstract. Pressurization of natural faults as a result of repository-induced effects can lead to their reactivation and permeability generation in case such features are present near disposal tunnels. Potential driving forces for such pressurization are the temperature increase caused by heat-producing high-level radioactive waste and the generation of hydrogen and other gases due to corrosion of engineered materials. We are primarily concerned about pressurization and fault activation in host rocks and faults that have very low natural permeability for pore pressure increases to dissipate, such as the argillite rocks currently investigated in Switzerland, France and other countries. This presentation discusses a series of in situ experiments of fault activation by fluid injection conducted in the argillite rock (Opalinus clay) at the Mont Terri underground research laboratory in Switzerland. A multi-model monitoring test bed was installed at Mont Terri that includes distributed fiber optics for strain, temperature, and acoustics; local fault pore pressure and three-dimensional displacement sensors; active seismic imaging; and passive seismic monitoring. The fault experiments (and their subsequent analysis via hydromechanical modeling) provide a new fundamental understanding of the coupling between pore pressure, fault deformation and permeability generation as a function of time and allow exploring how seismic and aseismic events may impact the integrity of faulted argillite host rock. Our experimental observations demonstrate that significant flow (and transport) can occur along the initially impermeable argillite fault when rupture is activated. However, the fault permeability decreases to almost its pre-activation value when fluid injection ceases and fluid pressure drops. Dilatant slip on the fault plane alone does not explain the observed increase in fault permeability; pressure-induced fault opening also plays a role, favored by the softness of the shale along with the fact that the structure of the fault zone prevents fluids from diffusing into the adjacent damage zone. Rupture initiation and permeability generation is initially aseismic, associated only with an increase in noise level and emerging tremors. Micro-earthquakes are initiated later in the experiments and typically occur away from the fluid-pressurized area. Hydromechanical models show that stress transferred from the initial aseismic deformation can build up to stress criticality and later induce seismic rupture. After presenting the experimental results, we will close the presentation with an outlook to future experimental campaigns using the fault test bed at Mont Terri. We are currently planning a controlled thermal stimulation of the fault, where instead of fluid injection as a trigger mechanism we will heat up the nearby rock volume and measure potential effects on fault stability. Lessons learned from our past and future experiments will help inform the safety assessment of geologic disposal in argillite host rock.

The effect ofinduced optimism onearly pain processing: indication by contact heat evoked potentials (CHEPs) andthe sympathetic skin response (SSR).

Situationally induced optimism has been shown to influence several components of experimental pain. The aim of the present study was to enlarge these findings for the first time to the earliest components of the pain response by measuring contact heat evoked potentials (CHEPs) and the sympathetic skin response (SSR). Forty-seven healthy participants underwent two blocks of phasic thermal stimulation. CHEPs, the SSR and self-report pain ratings were recorded. Between the blocks of stimulation, the 'Best Possible Self' imagery and writing task was performed to induce situational optimism. The optimism manipulation was successful in increasing state optimism. It did, however, neither affect pain-evoked potentials nor the SSR nor self-report pain ratings. These results suggest that optimism does not alter early responses to pain. The higher-level cognitive processes involved in optimistic thinking might only act on later stages of pain processing. Therefore, more research is needed targeting different time frames of stimulus processing and response measures for early and late pain processing in parallel.

Coordination Trap Induced Structural and Luminescent Property Transformation of Low Dimensional Organic‐Inorganic Hybrid Perovskites

AbstractHerein, a coordination trap strategy is proposed for constructing stimulus‐responsive phosphorescent perovskites. Hydroxyl groups are selected as trap groups and introduced into benzylamine hydrochloride of Cd‐based perovskite. The resulting two‐dimensional (2D) perovskite (C7H10NO)2CdCl4·H2O (H1) exhibits blue fluorescence at 405 nm and green phosphorescence at 482 nm under 365 nm excitation. After introducing guest Mn2+, due to the passivation of defects, the doped H1 (H1‐M) achieves orange phosphorescence (λ = 615 nm) of Cd2+. Interestingly, because thermal stimulation induces the coordination of hydroxyl groups with metal ions, H1 and H1‐M are transformed into the zero‐dimensional (0D) perovskite (C7H10NO)2CdCl4 (H2) and doped H2 (H2‐M), respectively. The coordination immobilizes the organic molecules, thus resulting in a large increase in the phosphorescence lifetime and a strong green afterglow of H2. The coordination also transforms the luminescent center of the doped perovskite from the host metal ion of H1‐M to the guest metal ion of H2‐M, achieving red phosphorescence of Mn2+ at 685 nm. Under water vapor, H2 and H2‐M are reversibly converted to H1 and H1‐M, respectively. Based on the above phenomena, a multilevel anti‐counterfeit encryption system with water/heat stimulus‐response is developed, which provides a new idea for the design of stimulus‐responsive phosphorescent intelligent materials.

NAG-1/GDF-15 Transgenic Female Mouse Shows Delayed Peak Period of the Second Phase Nociception in Formalin-induced Inflammatory Pain.

Non-steroidal anti-inflammatory drug-activated gene-1 (NAG-1), also known as growth differentiation factor-15 (GDF-15), is associated with cancer, diabetes, and inflammation, while there is limited understanding of the role of NAG-1 in nociception. Here, we examined the nociceptive behaviors of NAG-1 transgenic (TG) mice and wild-type (WT) littermates. Mechanical sensitivity was evaluated by using the von Frey filament test, and thermal sensitivity was assessed by the hot-plate, Hargreaves, and acetone tests. c-Fos, glial fibrillary acidic protein (GFAP), and ionized calcium binding adaptor molecule-1 (Iba-1) immunoreactivity was examined in the spinal cord following observation of the formalin-induced nociceptive behaviors. There was no difference in mechanical or thermal sensitivity for NAG-1 TG and WT mice. Intraplantar formalin injection induced nociceptive behaviors in both male and female NAG-1 TG and WT mice. The peak period in the second phase was delayed in NAG-1 TG female mice compared with that of WT female mice, while there was no difference in the cumulative time of nociceptive behaviors between the two groups of mice. Formalin increased spinal c-Fos immunoreactivity in both TG and WT female mice. Neither GFAP nor Iba-1 immunoreactivity was increased in the spinal cord of TG and WT female mice. These findings indicate that NAG-1 TG mice have comparable baseline sensitivity to mechanical and thermal stimulation as WT mice and that NAG-1 in female mice may have an inhibitory effect on the second phase of inflammatory pain. Therefore, it could be a novel target to inhibit central nervous system response in pain.

Investigation of kinetics of semi-clathrate formation for CO2 capture in the presence of L-methionine amino acid

ABSTRACT Gas hydrates cater to several applications including methane/natural gas storage, CO2 capture, gas separation, desalination, etc. Semi-clathrates are a class of inclusion compounds in which a part of guest molecule (typically anion of tertiary butyl ammonium salts) involves in the formation of cage structure along with water and the other remaining part of guest molecule (cation) occupies and stabilizes the gas hydrate structure. This study is the first effort to explore the kinetics of the formation of tertiary butyl ammonium chloride (TBAC) semi clathrate in the presence of CO2 without and with the addition of a kinetic promoter (L-methionine amino acid). Experimental conditions of the study include starting pressure of 3.4 MPa and temperatures in the range of 279.2–283.2 K. Kinetics of TBAB-CO2 and TBAC-CO2 mixed semi-clathrates have been compared and reported along with morphology observations under similar experimental conditions. TBAC-CO2 mixed semi-clathrates showcase significant reduction in induction time in comparison to TBAB-CO2 mixed semi-clathrates. Also, gas uptake (CO2 storage capacity) is observed to be slightly better for TBAC mixed semi-clathrates at lower concentrations (5 wt%). Though l-methionine amino acid aids in the reduction of t90 (time taken for 90% completion of hydrate formation) for TBAB-CO2 system, such an effect was not observed for TBAC-CO2 system. Formed semi-clathrates can be easily dissociated with low-grade waste heat to release the stored CO2 (based on the observed dissociation by thermal stimulation in conducted experiments), making it an excellent contender for Carbon Capture Utilization and Storage (CCUS) Technology.

Highly Efficient One-Pot Synthesis of Hexakis(m-phenyleneimine) Macrocyle Cm6 and the Thermostimulated Self-Healing Property through Dynamic Covalent Chemistry.

Highly efficient one-pot synthesis of hexakis(m-phenyleneimine) macrocycle Cm6 from acetalprotected AB-type monomer, m-aminobenzaldehyde diethylacetal, was successfully achieved based on imine dynamic covalent chemistry and precipitation-driven cyclization. The structure of Cm6 in the solid state was determined using CP/MAS NMR, X-ray single crystallographic analysis, and WAXD. Macrocycle Cm6 is composed of six phenylene and imine bonds facing the same direction, with nitrogen atoms arranged on the outside of the ring, and has a chair conformation, as predicted from DFT calculation. The macrocycle forms π-stacked columnar aggregates and hexagonally closest-packed structure. The cyclization process was investigated using MALDI-TOF MS and NMR. A mechanism of precipitation-driven cyclization based on imine dynamic covalent chemistry and π-stacked columnar aggregation is proposed. Both the nature of imine linkage and the shape anisotropy of the macrocycle played an important role in the single one-pot synthesis. The water-mediated mutual conversion between macrocycle Cm6 and linear oligomers driven by thermal stimulation was analyzed using MALDI-TOF MS and GPC methods. Macrocycle Cm6 with a dynamic covalent imine bond exhibited self-healing properties when stimulated using heat.

Assessing brain function in stressed healthy individuals following the use of a combination of green tea, Rhodiola, magnesium, and B vitamins: an fMRI study.

This randomized, controlled, single-blinded trial assessed the effect of magnesium (Mg)-Teadiola (Mg, vitamins B6, B9, B12, Rhodiola, and green tea/L-theanine) versus placebo on the brain response to stressful thermal stimulus in chronically stressed, but otherwise healthy subjects. Impacts on stress-related quality-of-life parameters (depression, anxiety, sleep, and perception of pain) were also explored. The study recruited a total of 40 adults (20 per group), suffering from stress for more than 1 month and scaling ≥14 points on the Depression Anxiety Stress Scale (DASS)-42 questionnaire at the time of inclusion. Individuals received oral Mg-Teadiola or placebo for 28 days (D). fMRI analysis was used to visualize the interplay between stress and pain cerebral matrices, using thermal stress model, at baseline (D0) and after D28. Based on blood-oxygen-level-dependent (BOLD) signal variations during the stress stimulation (before pain perception), a significantly increased activation between D0 and D28 was observed for left and right frontal area (p = 0.001 and p = 0.002, respectively), left and right anterior cingulate cortex (ACC) (p = 0.035 and p = 0.04, respectively), and left and right insula (p = 0.034 and p = 0.0402, respectively) in Mg-Teadiola versus placebo group. During thermal pain stimulation, a significantly diminished activation of the pain matrix was observed between D0 and D28, for left and right prefrontal area (both p = 0.001), left and right insula (p = 0.008 and p = 0.019, respectively), and left and right ventral striatum (both p = 0.001) was observed in Mg-Teadiola versus placebo group. These results reinforce the clinical observations, showing a perceived benefit of Mg-Teadiola on several parameters. After 1 month of treatment, DASS-42 stress score significantly decreased in Mg-Teadiola group [effect size (ES) -0.46 (-0.91; -0.01), p = 0.048]. Similar reductions were observed on D14 (p = 0.011) and D56 (p = 0.008). Sensitivity to cold also improved from D0 to D28 for Mg-Teadiola versus placebo [ES 0.47 (0.02; 0.92) p = 0.042]. Supplementation with Mg-Teadiola reduced stress on D28 in chronically stressed but otherwise healthy individuals and modulated the stress and pain cerebral matrices during stressful thermal stimulus.

Differential Effects of Thermal Stimuli in Eliciting Temporal Contrast Enhancement: A Psychophysical Study

Offset analgesia (OA) is observed when pain relief is disproportional to the reduction of noxious input and is based on temporal contrast enhancement (TCE). This phenomenon is believed to reflect the function of the inhibitory pain modulatory system. However, the mechanisms contributing to this phenomenon remain poorly understood, with previous research focusing primarily on painful stimuli and not generalizing to nonpainful stimuli. Therefore, the aim of this study was to investigate whether TCE can be induced by noxious as well as innocuous heat and cold stimuli. Asymptomatic subjects (n = 50) were recruited to participate in 2 consecutive experiments. In the first pilot study (n = 17), the parameters of noxious and innocuous heat and cold stimuli were investigated in order to implement them in the main study. In the second (main) experiment, subjects (n = 33) participated in TCE paradigms consisting of 4 different modalities, including noxious heat (NH), innocuous heat (IH), noxious cold (NC), and innocuous cold (IC). The intensity of the sensations of each thermal modality was assessed using an electronic visual analog scale. TCE was confirmed for NH (P < .001), NC (P = .034), and IC (P = .002). Conversely, TCE could not be shown for IH (P = 1.00). No significant correlation between TCE modalities was found (r < .3, P > .05). The results suggest that TCE can be induced by both painful and nonpainful thermal stimulation but not by innocuous warm temperature. The exact underlying mechanisms need to be clarified. However, among other potential mechanisms, this may be explained by a thermo-specific activation of C-fiber afferents by IH and of A-fiber afferents by IC, suggesting the involvement of A-fibers rather than C-fibers in TCE. More research is needed to confirm a peripheral influence. PerspectiveThis psychophysical study presents the observation of temporal contrast enhancement during NH, NC, and innocuous cold stimuli but not during stimulation with innocuous warm temperatures in healthy volunteers. A better understanding of endogenous pain modulation mechanisms might be helpful in explaining the underlying aspects of pain disorders.

Mechanical behavior and optimization of constitutive prediction model for Epoxy/Al energetic composite materials considering temperature and strain rate effects

Epoxy/Al as a functional structural energetic composite material that can be used as an adhesive, energetic fragments and warhead shells due to its high energy density, low density, and high strength. It can release a large amount of chemical energy (about 21.36 kJ/g) through chemical reactions when subjected to high-speed impact and thermal stimulation. Whether used as a matrix or auxiliary component, it has enormous development potential. Therefore, it is particularly important to study the mechanical properties of Epoxy/Al energetic composite materials under different temperature environments and strain rates of loading. This article describes the preparation of Epoxy/Al specimens with a mass percentage of 70%–30% using vacuum curing after 24 h under 0.8 Bar and 50 °C. The mechanical properties of Epoxy/Al specimens under different loading conditions were characterized using a high and low temperature universal testing machine and a separate Hopkinson experimental system. The modulus prediction method of binary composite materials was improved by combining SEM (scanning electron microscopy) and microstructure, and an adaptive constitutive model was developed combined with the K Srinivas model and neural network model based on the Sherwood Frost empirical constitutive relationship. The results show that Epoxy/Al energetic composite material has a significant temperature effect. When the temperature exceeds 100 °C, Epoxy/Al energetic composite material will be a significant physical and chemical property transition (the specimen exhibits viscous fluid characteristics and gradually begins to slowly decompose). As the temperature decreases, the specimen gradually exhibits a certain degree of brittleness and strength is improved. Due to the deformation, displacement, and interfacial debonding of internal particles during the loading process, Epoxy/Al materials exhibit excellent impact energy absorption effects, with energy absorption reaching 15.30 MJ/m3 at room temperature, and unit mass cost much lower than popular CFRP (carbon fiber-reinforced polymer) materials (CFRP energy absorption cost is 0.268 J/g/£, while Epoxy/Al materials do not exceed 0.013 J/g/£). During the dynamic loading process, Epoxy/Al energetic composite materials exhibit a phenomenon of structural reconstruction and enhancement throughout the entire loading process. The maximum strength at room temperature can reach 240.70 MPa, which is superior to all existing energetic materials of the same type. By introducing interface effects and quantifying them in the Halpin Tsai model, the existing prediction method for the Young's modulus of binary particle added composite materials has been effectively improved, reducing the prediction error of the Young's modulus of Epoxy/Al energetic composite materials from 14.2% to 2.4%. The numerical simulation results indicate that the newly developed constitutive model has high accuracy and can better reflect the mechanical properties of Epoxy/Al materials. The development method of this constitutive model has a positive contribution to the development of composite materials.

Thermo-Chemical Resistance to Combination Therapy of Glioma Depends on Cellular Energy Level.

Thermal therapy has been widely used in clinical tumor treatment and more recently in combination with chemotherapy, where the key challenge is the treatment resistance. The mechanism at the cellular level underlying the resistance to thermo-chemical combination therapy remains elusive. In this study, we constructed 3D culture models for glioma cells (i.e., 3D glioma spheres) as the model system to recapitulate the native tumor microenvironment and systematically investigated the thermal response of 3D glioma spheres at different hyperthermic temperatures. We found that 3D glioma spheres show high viability under hyperthermia, especially under high hyperthermic temperatures (42 °C). Further study revealed that the main mechanism lies in the high energy level of cells in 3D glioma spheres under hyperthermia, which enables the cells to respond promptly to thermal stimulation and maintain cellular viability by upregulating the chaperon protein Hsp70 and the anti-apoptotic pathway AKT. Besides, we also demonstrated that 3D glioma spheres show strong drug resistance to the thermo-chemical combination therapy. This study provides a new perspective on understanding the thermal response of combination therapy for tumor treatment.

Thermally responsive copper alginate/nano ZnO/quaternary ammonium chitosan triple antimicrobial fiber

Smart and controllable antibacterial fabrics have enormous potential in the textile, medical, and healthcare fields. In this study, nano zinc oxide (ZnO) was synthesized in situ in sodium alginate (Alg) solution, and the above-mentioned solution was combined with quaternary ammonium chitosan (QAC) to form a polyelectrolyte spinning solution. A composite antimicrobial fiber with thermally responsive properties was created by wet spinning through CuCl2 coagulation bath crosslinking and in-situ synthesis of CuS on the fiber surface. Benefitting from the mixed-solubility synergistic effect of Alg and QAC, the mechanical properties of composite fiber materials were greatly improved. The tensile strength of the fiber was 58 ± 1.5 MPa, while the fiber material maintained good biocompatibility, moisture absorption, air permeability, and antibacterial properties. Adding a CuS layer gave the composite fibers photothermal response-ability and further promoted the controllable antibacterial properties of the materials. The maximum rings of inhibition of the copper alginate/nano ZnO/quaternary ammonium chitosan/ copper sulphide (CAlg/ZnO/QAC/CuS) composite fiber against S. aureus, E. coli and P. aeruginosa were 2.9 mm, 2.5 mm and 2.2 mm respectively. This was attributed to the synergistic effect of the inorganic and organic antimicrobial agents of nano ZnO and QAC component as well as the thermal stimulation response of CuS. These characteristics of the smart responsive composite fibers indicate their potential applications in medical dressings, special textiles, and healthcare materials.

Full-thickness skin rejuvenation by a novel dual-length microneedle radiofrequency device: A proof-of-concept study using human skin.

A novel dual-length microneedle radiofrequency (DLMR) device has been developed to achieve full-thickness skin rejuvenation by stimulating the papillary and reticular dermis simultaneously. This device's dual-level targeting concept need to be validated on human skin, although its clinical efficacy has been demonstrated in a previous study. This study evaluated the dual-depth targeting capability and the ability to induce rejuvenation in each layer of vertical skin anatomy, that is, the epidermis, papillary dermis, and reticular dermis, using full-thickness human facial skin samples. Human facial skin samples were obtained from 13 Asian patients who had facelift surgery. To validate the dual-depth targeting concept, DMLR-treated skin samples were analyzed using a digital microscope, thermal imaging, and hematoloxylin and eosin (H&E) staining immediately after DLMR application. On samples stained with H&E, Masson's tricrome, and Verhoeff-Van Gieson, histological observation and morphometric analysis were performed. Total collagen assay (TCA) and quantitative real-time polymerase chain reaction (qPCR) were used to assess changes in total collagen content and mRNA expression levels of collagen types I/III and vimentin, respectively. The DLMR device successfully induced thermal stimulation in the papillary and reticular dermis. The thickness, stacks, and dermal-epidermal junction convolution of the epidermis treated with DLMR were significantly increased. Collagen bundles in the dermis treated with DLMR exhibited a notable increase in thickness, density, and horizontal alignment. Dermal collagen levels were significantly higher in the morphometric and TCA data, as well as in the qPCR data for dermal matrix proteins. Our DLMR device independently and precisely targeted the papillary and reticular dermis, and it appears to be an effective modality for implementing full-thickness rejuvenation.