Mechanism of Tea Polyphenols in Alleviating Thermal Damage Based on Network Pharmacology

[Objective]This paper was to investigate the action targets and pathways of tea polyphenols in alleviating heat stress-induced injury by using network pharmacological analysis and an H9C2 cell model.[Method]First,the corresponding targets of tea polyphenols were obtained from the PubChem database.Then,the core targets were screened based on topological parameters.The relevant metabolism pathways of tea polyphenols related to diseases were identified through GO functional annotation and KECG signaling pathway enrichment.Moreover,common targets for thermal injury and targets of tea polyphenols were obtained.Then,GO functional annotation was performed to explore the pathway of tea polyphenols in alleviating heat stress damage.H9C2 cells were cultured at 42 C to construct the heat stress model,and the cells were treated with 10μg/mL tea polyphenols.The key genes were confirmed using RT-PCR technology.[Result]The study yielded 364 targets corresponding to tea polyphenols,including 68 core targets.These targets are related to various biological processes such as involve oxidative stress,cancer,lipopolysaccharide-mediated signaling pathways,antiviral responses,regulation of cellular response to heat,apoptosis,and cellular lipid metabolic metabolism.Tea polyphe nols alleviate thermal damage by targeting BCL2,HSP90AA1,HSPA1A,JUN,MAPK1,NFKB1,NFKBIA,NOS3,and TP53.Moreover,10 mg/L tea polyphenols were found to upregulate the transcription levels of Hsp70,HO-1,NQ-O1,Nrf2,and MAPKI,and the transcription levels of Bax/Bcl2,p38,and JNK were downregulated to alleviate the heat stress-induced injury.[Conclusion]Tea polyphenols may enhance the antioxidant ability of H9C2 cells and inhibit cell apoptosis,thereby reducing heat stress injury.

Extraction method of nanoparticles concentration distribution from magnetic particle image and its application in thermal damage of magnetic hyperthermia

Magnetic particle imaging(MPI)technology can generate a real-time magnetic nanoparticle(MNP)distribution image for biological tissues,and its use can overcome the limitations imposed in magnetic hyperthermia treatments by the unpredictable MNP distribution after the intratumoral injection of nanofluid.However,the MNP concentration distribution is generally difficult to be extracted from MPI images.This study proposes an approach to extract the corresponding concentration value of each pixel from an MPI image by a least squares method(LSM),which is then translated as MNP concentration distribution by an interpolation function.The resulting MPI-based concentration distribution is used to evaluate the treatment effect and the results are compared with the ones of two baseline cases under the same dose:uniform distribution and MPI-based distribution considering diffusion.Additionally,the treatment effect for all these cases is affected by the blood perfusion rate,which is also investigated deeply in this study.The results demonstrate that the proposed method can be used to effectively reconstruct the concentration distribution from MPI images,and that the weighted LSM considering a quartic polynomial for interpolation provides the best results with respect to other cases considered.Furthermore,the results show that the uniformity of MNP distribution has a positive correlation with both therapeutic temperature distribution and thermal damage degree for the same dose and a critical power dissipation value in the MNPs.The MNPs uniformity inside biological tissue can be improved by the diffusion behavior after the nanofluid injection,which can ultimately reflect as an improvement of treatment effect.In addition,the blood perfusion rate considering local temperature can have a positive effect on the treatment compared to the case which considers a constant value during magnetic hyperthermia.

Effect of loading rates on the characteristics of thermal damage for mudstone under different temperatures

The uniaxial compression tests for mudstone specimens are carried out with four different loading rates from room temperature to 400℃ by using the Rock Mechanics Servo-controlled Testing System MTS810 and high temperature furnace MTS652.02.The mechanical properties of mudstone with various loading rates are studied under different temperature conditions.The results show that when temperature increases from room temperature to 400℃ and loading rate is less than 0.03 mm/s,the peak strength of mudstone specimen decreases as loading rate increases,while the various peak strengths show significant differences when loading rate exceeds 0.03 mm/s.At room temperature,the elastic modulus decreases at the first time and then increases with loading rate rising.When the temperature is between200 and 400℃,the elastic modulus presents a decreasing trend with increasing loading rate.With increasing the loading rate,the number of fragments in mudstone becomes larger and even the powder is observed in mudstone with higher loading rate.Under high loading rate,the failure mode of mudstone specimens under different temperatures is mainly conical damage.

Quantification of thermal damage in skin tissue

Skin thermal damage or skin burns are the most commonly encountered type of trauma in civilian and military communities. Besides, advances in laser, microwave and similar technologies have led to recent developments of thermal treatments for disease and damage involving skin tissue, where the objective is to induce thermal damage precisely within targeted tissue structures but without affecting the surrounding, healthy tissue. Further, extended pain sensation induced by thermal damage has also brought great problem for burn patients. Thus, it is of great importance to quantify the thermal damage in skin tissue. In this paper, the available models and experimental methods for quantification of thermal damage in skin tissue are discussed.

Micro-macro evolution of mechanical behaviors of thermally damaged rock:A state-of-the-art review

The influence of thermal damage on macroscopic and microscopic characteristics of different rocks has received much attention in the field of rock engineering.When the rocks are subjected to thermal treatment,the change of macroscopic characteristics and evolution of micro-structure would be induced,ultimately resulting in different degrees of thermal damage in rocks.To better understand the thermal damage mechanism of different rocks and its effect on the rock performance,this study reviews a large number of test results of rock specimens experiencing heating and cooling treatment in the laboratory.Firstly,the variations of macroscopic behaviors,including physical parameters,mechanical parameters,thermal conductivity and permeability,are examined.The variations of mechanical parameters with thermal treatment variables(i.e.temperature or the number of thermal cycles)are divided into four types.Secondly,several measuring methods for microstructure,such as polarizing microscopy,fluorescent method,scanning electron microscopy(SEM),X-ray computerized tomography(CT),acoustic emission(AE)and ultrasonic technique,are introduced.Furthermore,the effect of thermal damage on the mechanical parameters of rocks in response to different thermal treatments,involving temperature magnitude,cooling method and thermal cycle,are discussed.Finally,the limitations and prospects for the research of rock thermal damage are proposed.

A creep model for ultra-deep salt rock considering thermal-mechanical damage under triaxial stress conditions

To investigate the specific creep behavior of ultra-deep buried salt during oil and gas exploitation,a set of triaxial creep experiments was conducted at elevated temperatures with constant axial pressure and unloading confining pressure conditions.Experimental results show that the salt sample deforms more significantly with the increase of applied temperature and deviatoric loading.The accelerated creep phase is not occurring until the applied temperature reaches 130℃,and higher temperature is beneficial to the occurrence of accelerated creep.To describe the specific creep behavior,a novel three-dimensional(3D)creep constitutive model is developed that incorporates the thermal and mechanical variables into mechanical elements.Subsequently,the standard particle swarm optimization(SPSO)method is adopted to fit the experimental data,and the sensibility of key model parameters is analyzed to further illustrate the model function.As a result,the model can accurately predict the creep behavior of salt under the coupled thermo-mechanical effect in deep-buried condition.Based on the research results,the creep mechanical behavior of wellbore shrinkage is predicted in deep drilling projects crossing salt layer,which has practical implications for deep rock mechanics problems.

Microstructural and thermal properties of coal measure sandstone subjected to high temperatures

To study the microscopic structure,thermal and mechanical properties of sandstones under the influence of temperature,coal measure sandstones from Southwest China are adopted as the research object to carry out high-temperature tests at 25℃-1000℃.The microscopic images of sandstone after thermal treatment are obtained by means of polarizing microscopy and scanning electron microscopy(SEM).Based on thermogravimetric(TG)analysis and differential scanning calorimetric(DSC)analysis,the model function of coal measure sandstone is explored through thermal analysis kinetics(TAK)theory,and the kinetic parameters of thermal decomposition and the thermal decomposition reaction rate of rock are studied.Through the uniaxial compression experiments,the stress‒strain curves and strength characteristics of sandstone under the influence of temperature are obtained.The results show that the temperature has a significant effect on the microstructure,mineral composition and mechanical properties of sandstone.In particular,when the temperature exceeds 400℃,the thermal fracture phenomenon of rock is obvious,the activity of activated molecules is significantly enhanced,and the kinetic phenomenon of the thermal decomposition reaction of rock appears rapidly.The mechanical properties of rock are weakened under the influence of rock thermal fracture and mineral thermal decomposition.These research results can provide a reference for the analysis of surrounding rock stability and the control of disasters caused by thermal damage in areas such as underground coal gasification(UCG)channels and rock masses subjected to mine fires.

Spatial gradient distributions of thermal shock-induced damage to granite

In this study,we attempted to investigate the spatial gradient distributions of thermal shock-induced damage to granite with respect to associated deterioration mechanisms.First,thermal shock experiments were conducted on granite specimens by slowly preheating the specimens to high temperatures,followed by rapid cooling in tap water.Then,the spatial gradient distributions of thermal shock-induced damage were investigated by computed tomography(CT)and image analysis techniques.Finally,the influence of the preheating temperature on the spatial gradients of the damage was discussed.The results show that the thermal shock induced by rapid cooling can cause more damage to granite than that induced by slow cooling.The thermal shock induced by rapid cooling can cause spatial gradient distributions of the damage to granite.The damage near the specimen surface was at a maximum,while the damage inside the specimen was at a minimum.In addition,the preheating temperature can significantly influence the spatial gradient distributions of the thermal shock-induced damage.The spatial gradient distribution of damage increased as the preheating temperature increased and then decreased significantly over 600
C.When the preheating temperature was sufficiently high(e.g.800
C),the gradient can be ignored.

Coupled thermo-mechanical constitutive damage model for sandstone

Underground rock dynamic disasters are becoming more severe due to the increasing depth of human operations underground.Underground temperature and pressure conditions contribute significantly to these disasters.Therefore,it is important to understand the coupled thermo-mechanical(TM)behaviour of rocks for the long-term safety and maintenance of underground tunnelling and mining.Moreover,investigation of the damage,strength and failure characteristics of rocks under triaxial stress conditions is important to avoid underground rock disasters.In this study,based on Weibull distribution and Lemaitre's strain equivalent principle,a statistical coupled TM constitutive model for sandstone was established under high temperature and pressure conditions.The triaxial test results of sandstone under different temperature and pressure conditions were used to validate the model.The proposed model was in good agreement with the experimental results up to 600℃.The total TM damage was decreased with increasing temperature,while it was increased with increasing confining pressure.The model's parameters can be calculated using conventional laboratory test results.

Influence of cooling speed on the physical and mechanical properties of granite in geothermal-related engineering

In deep-earth engineering,the high earth temperature can significantly affect the rock's mechanical properties,especially when the rock is cooled during the construction process.Accordingly,whether the cooling speed affects the mechanical and physical properties of rocks is worth to be investigated.The present study explored the influence of the cooling rate on the physical and chemical properties of granite heated at 25–800°C.The mechanical and physical properties involved in this study included uniaxial compression strength,peak strain,modulus,P-wave velocity,mass and volume,the change of which could reflect the sensitivity of granite to the cooling rate.Acoustic emission(AE)monitoring,microscopic observation,and X-ray diffraction(XRD)are used to analyze the underlying damage mechanism.It is found that more AE signals and large-scale cracks are accounted for based on the b-value method when the specimens are cooled by water.Furthermore,the microscopic observation by polarized light microscopy indicates that the density,opening degree,and connectivity of the cracks under water cooling mode are higher than that under natural cooling mode.In addition,the XRD illustrates that there is no obvious change in mineral content and diffraction angle at different temperatures,which confirms that the change of mechanical properties is not related to the chemical properties.The present conclusion can provide a perspective to assess the damage caused by different cooling methods to hot rocks.

Macro and micro mechanics behavior of granite after heat treatment by cluster model in particle flow code

In this paper, a cluster model in particle flow code was used to simulate granite specimens after heat treatment under uniaxial compression. The results demonstrated that micro-cracks are randomly distributed in the specimen when the temperature is below 300?C, and have partial coalescence when the temperature is up to 450?C, then form macro-cracks when the temperature is above 600?C. There is more inter-granular cracking than intra-granular cracking, and their ratio increases with increasing temperature.The micro-cracks are almost constant when the temperature decreases from 900?C to room temperature, except for quartz α–β phase transition temperature(573?C). The fracture evolution process is obviously affected by these cracks, especially at 600–900?C. Elevated temperature leads to easily developed displacement between the grains, and the capacity to store strain energy becomes weaker, corresponding to the plasticity of granite after heat treatment.

Effects of microwave radiation on dynamic compressive properties of basalt

The dynamic mechanical properties of basalt affected by microwave were investigated by performing dynamic compressive tests using the SHPB system.Meanwhile,the thermal damage of the treated basalt was characterized by ultrasonic non-destructive testing and nuclear magnetic resonance technology.The results show that with the increase of microwave power and exposure time,the P-wave velocity,dynamic compressive strength and elastic modulus decrease continuously,and the dynamic failure mode tends to be a more complex fracturing.The increase in microwave power and exposure time can enhance the temperature difference and transfer coefficient among minerals,hence intensifying the rock damage induced by thermal shock.

Influence of the heat irrigating effect of radiofrequency ablation on regional liver tissue in Bama miniature pigs

BACKGROUND The results of the heat irrigating effect of radiofrequency ablation(RFA)are uncertain,and the accurate impact of the heat irrigating effect on regional liver tissue is unknown due to a lack of control experiments.AIM The aim of this study was to determine the influence of the heat irrigating effect of RFA on regional liver tissue in Bama miniature pigs.METHODS Eight Bama miniature pigs were randomly divided into the observation group(group A)and the control group(group B),with 4 pigs/group.An RFA electrode needle was implanted near the hepatic segment vasculature(3-5 mm from the hepatic segment portal vein)under ultrasound guidance in group A.Similarly,an RFA electrode needle was implanted far from the hepatic segment vasculature(8-10 mm from the hepatic segment portal vein)in group B.The left internal lobe and right medial lobe were chosen as RFA sites in each pig.RFA was performed at the left internal lobe on day one in each pig,and at the right medial lobe 7 d later.Each RFA lasted 12 min.The general status of the pigs and serious complications were observed during the perioperative period.The pigs were sacrificed and the livers were removed immediately after RFA on the eighth day.The samples were roughly observed.Hematoxylin-eosin and Ki67 staining,as well as TUNEL detection,were performed on the tissue sections.RESULTS All 8 animals successfully underwent ultrasound-guided RFA.No serious complications,such as massive hemorrhage,biliary fistula,severe pleural effusion,pneumothorax,peripheral organ failure,or renal failure occurred in any of the animals during the perioperative period.The RFA coagulative necrosis lesion was spherical and the surrounding liver tissue showed an inflammatory response.The difference in the Suzuki score of the liver tissue surrounding the ablated portal vein,and its distal area between groups A and B,was statistically significant(P<0.05).More apoptotic cells were seen in liver tissue surrounding the ablated portal vein and its distal area in group A,while fewer apoptotic cells in the same area were seen in group B.The difference in the apoptotic index of the above area between group A and group B was statistically significant(P<0.05).Cells staining positive for Ki67 were observed in liver tissue at the left internal lobe around the ablated portal vein and its distal area in group A.No Ki67 staining positive cells were observed in other tissue sections.The difference in the Ki67 staining positive index in the above area was statistically significant(P<0.05)between group A and group B.CONCLUSION Changes as a result of thermal damage occur in liver tissue around the ablated portal vein and its distal area due to the heat irrigating effect when the RFA electrode tip is close to(<5 mm)the portal vein.

Ultrasonic testing and microscopic analysis on concrete under sulfate attack and cyclic environment

The damage process of concrete exposed to sodium sulfate attack and drying-wetting cycles was investigated. The water to binder(W/B) ratio and the concentration of sulfate solution were taken as variable parameters. Through the experiment, visual change, relative dynamic modulus of elasticity(RDME) and the surface damage layer thickness of concrete were measured.Furthermore, SEM and thermal analysis were used to investigate the changing of microstructure and corrosion products of concrete.The test results show that the ultrasonic velocity is related to the damage layer of concrete. It approves that an increase in damage layer thickness reduces the compactness and the ultrasonic velocity. The deterioration degree of concrete could be estimated effectively by measuring the surface damage layer and the RDME of concrete. It is also found that the content of gypsum in concrete is less than that of ettringite in test, and some gypsum is checked only after a certain corrosion extent. When the concrete is with high W/B ratio or exposed to high concentration of sulfate solution, the content of ettringite first increases and then decreases with corrosion time. However, the content of gypsum increases at a steady rate. The content of corrosion products does not correspond well with the observations of RDME change, and extensive amount of corrosion products can be formed before obvious damage occurs.

Synergistic injection of the thermosensitive hydrogel and Bi-based alloy bone cement for orthopaedic repair

Low-melting-point alloys have the advantages of good biocompatibility, plasticity, and near-bone mechanical strength, making them suitable as bone defect-filling materials for direct injection into defective bone sites. However, using low-melting-point alloys for orthopedic implants poses the challenge of causing thermal damage to the surrounding bone tissue during injection. In this study, a thermosensitive hydrogel is prepared and synergistically injected into the bone defect site with BiInSn. BiInSn solidifies and releases heat during injection, while the thermosensitive hydrogel absorbs heat and transforms into a gel state,encapsulating BiInSn. Therefore, the surrounding bone tissue is effectively protected from thermal damage. When BiInSn and the thermosensitive hydrogel were injected synergistically, in vitro thermal experiments revealed that the maximum temperature of the surrounding bone tissue reached 42℃. This temperature is below the 47℃ threshold, which causes permanent damage to bone tissues. In vivo experiments demonstrated that rats in the BiInSn-thermosensitive hydrogel group exhibited better recovery at the bone defect sites. These results suggest that the synergistic injection of Bi-based alloy and thermosensitive hydrogel is beneficial in reducing thermal damage to bone tissue, guiding bone tissue growth, and effectively facilitating the repair of bone defects.

Numerical study on thermal therapy of triple layer skin tissue using fractional bioheat model

This paper deals with the study of heat transfer and thermal damage in triple layer skin tissue using fractional bioheat model. Here, we consider three types of heating viz. sinusoidal heat flux, constant temperature and constant heat flux heating on skin surface. An implicit finite difference scheme is obtained by approximating fractional time derivative by quadrature formula and space derivative by central difference formula. The temperature profiles and thermal damage in the skin tissue are obtained to study the effect of fractional parameter a on diffusion process for constant temperature and heat flux boundary heating on skin surface. A parametric study for sinusoidal heat flux at skin surface has also been made.

Comparison between high-frequency irreversible electroporation and irreversible electroporation ablation of small swine liver:follow-up of DCE-MRI and pathological observations

Background:High-frequency irreversible electroporation(H-FIRE)is a novel,next-generation nanoknife technology with the advantage of relieving irreversible electroporation(IRE)-induced muscle contractions.However,the difference between IRE and H-FIRE with distinct ablation parameters was not clearly defined.This study aimed to compare the efficacy of the two treatments in vivo.Methods:Ten Bamaminiature swinewere divided into two group:five in the 1-day group and five in the 7-day group.The efficacy of IRE and H-FIRE ablation was compared by volume transfer constant(Krans),rate constant(Kep)and extravascular extracellular volume fraction(Ve)value of dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI),size of the ablation zone,and histologic analysis.Each animal underwent the IRE andH-FIRE.Temperatures of the electrodesweremeasured during ablation.DCE-MRI images were obtained 1,4,and 7 days after ablation in the 7-day group.All animals in the two groups were euthanized 1 day or 7 days after ablation,and subsequently,IRE and H-FIRE treated liver tissues were collected for histological examination.Student’s t test or Mann-Whitney U test was applied for comparing any two groups.One-way analysis of variance(ANOVA)test and Welch’s ANOVA test followed byHolm-Sidak’smultiple comparisons test,one-wayANOVAwith repeatedmeasures followed by Bonferroni test,or Kruskal-Wallis H test followed by Dunn’s multiple comparison test was used for multiple group comparisons and post hoc analyses.Pearson correlation coefficient test was conducted to analyze the relationship between two variables.Results:Higher Ve was seen in IRE zone than in H-FIRE zone(0.14±0.02 vs.0.08±0.05,t=2.408,P=0.043)on day 4,but no significant difference was seen in Ktrans or Kep between IRE and H-FIRE zones at all time points(all P>0.05).For IRE zone,the greatest Ktrans was seen on day 7,which was significantly higher than that on day 1(P=0.033).The ablation zone size of H-FIRE was significantly larger than IRE 1 day(4.74±0.88 cm^(2)vs.3.20±0.77 cm^(2),t=3.241,P=0.009)and 4 days(2.22±0.83 cm^(2)vs.1.30±0.50 cm^(2),t=2.343,P=0.041)after treatment.Apoptotic index(0.05±0.02 vs.0.73±0.06 vs.0.68±0.07,F=241.300,P<0.001)and heat shock protein 70(HSP70)(0.03±0.01 vs.0.46±0.09 vs.and 0.42±0.07,F=64.490,P<0.001)were significantly different between the untreated,IRE and H-FIRE zones,but no significant difference was seen in apoptotic index or HSP70 between IRE and H-FIRE zone(both P>0.05).Electrode temperature variations were not significantly different between the two zones(18.00±3.77℃ vs.16.20±7.45℃,t=0.682,P=0.504).The Ktrans value(r=0.940,P=0.017)and the Kep value(r=0.895,P=0.040)of the H-FIRE zone were positively correlated with the number of hepatocytes in the ablation zone.Conclusions:H-FIRE showed a comparable ablation effect to IRE.DCE-MRI has the potential to monitor the changes of H-FIRE ablation zone.

Theoretical and experimental study of surface texturing with laser machining

To explore the forming process and mechanism of the surface texture of laser micropits,this paper presents the thermal model of laser machining based on the Neumann boundary conditions and an investigation on the effects of various parameters on the processing.The surface profile and quality of the formed micropits were analyzed using NanoFocus 3D equipment through a design of experiment(DOE).The results showed that more intense melting and splashing occurred with higher power density and narrower pulse widths.Moreover,the compressive stress is an important indicator of the damage effects,and the circumferential thermal stress is the primary factor influencing the diameter expansion.During the process of laser machining,not only did oxides such as CuO and ZnO generate,the energy distribution also tended to decrease gradually from region#1 to region#3 based on an energy dispersive spectrometer(EDS)analysis.The factors significantly affecting the surface quality of the micropit surface texture are the energy and pulse width.The relationship between taper angle and energy is appropriately linear.Research on the formation process and mechanism of the surface texture of laser micropits provides important guidance for precision machining.