Exponential cell temperature regulation method and system for large dose electromagnetic irradiation cell non-thermal effect experiment
By employing an exponential temperature control method and utilizing electromagnetic and temperature modeling simulations to calculate the redundancy range of the airflow temperature change curve, the problems of insufficient irradiation dose and complex temperature control in existing technologies are solved, enabling efficient conduct of non-thermal effect experiments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- XIDIAN UNIV
- Filing Date
- 2022-08-09
- Publication Date
- 2026-06-09
AI Technical Summary
In existing experiments on the non-thermal effects of electromagnetic irradiation on cells, insufficient irradiation dose makes it difficult to detect non-thermal effects. Traditional temperature control methods are difficult to effectively distinguish between non-thermal and thermal effects, and temperature modulation is complex and time-consuming to implement.
An exponential temperature control method is adopted. Through electromagnetic modeling and temperature modeling simulation, the redundancy range of the airflow temperature change curve is calculated. The airflow temperature is controlled to keep it within the temperature change threshold range of non-thermal effects during the experiment. The airflow temperature change curve is generated using an exponential temperature control function.
It significantly increases the permissible irradiation dose for non-thermal effect experiments, simplifies the temperature control process, and improves the feasibility and efficiency of experiments.
Smart Images
Figure CN115270496B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of bioelectromagnetic experimental technology, and specifically relates to an exponential cell temperature control method and system for experiments on the non-thermal effects of high-dose electromagnetic irradiation on cells. Background Technology
[0002] In bioelectromagnetics, the "thermal effect" refers to the biological effect caused by the absorption of electromagnetic energy by biological samples, which is converted into heat energy, leading to a significant increase in temperature. The "non-thermal effect," on the other hand, is a biological effect directly induced by electromagnetic field energy and is independent of temperature changes. The non-thermal effects of electromagnetic radiation on cells are a research hotspot in bioelectromagnetics, and can provide insights into the mechanisms of electromagnetic wave stimulation and cellular responses, supporting the safe and beneficial development and application of various electromagnetic devices.
[0003] For a long time, experiments on the non-thermal effects of electromagnetic irradiation on cells have generally suffered from contradictory results and poor reproducibility of effects. One of the main reasons is that the non-thermal effects produced by traditional electromagnetic irradiation experimental devices are very weak and difficult to detect successfully with existing equipment and techniques. As Adair RK stated in his paper "Biophysical Limits on Athermal Effects of RF and Microwave Radiation[J]. Bioelectromagnetics,2003,24(1):39-48", in order to avoid a significant increase in temperature, the irradiation dose allowed in the experiment is relatively low, resulting in the electromagnetic energy obtained by biological samples being basically equal to the thermal noise energy of normal life activities, which cannot effectively excite non-thermal effects. In order to enhance the non-thermal effects to a level that can be successfully detected, the experiment needs to significantly increase the irradiation dose, such as increasing the incident power density of electromagnetic waves to 10mW / cm². 2 However, the resulting thermal effects can severely interfere with the identification and detection of non-thermal effects.
[0004] To avoid thermal effects, current electromagnetic irradiation experimental systems generally employ heat exchange to suppress cell temperature rise. Schuderer J et al., in their paper "In Vitro Exposure Systems for RF Exposures at 900 MHz[J].IEEE Transactions on Microwave Theory and Techniques,2004,52(8):2067-2075", described the sXc900 electromagnetic irradiation cell experimental system developed by the Swiss IT'IS Foundation. This system generates a constant airflow at the cell culture temperature to cool the cell samples in the waveguide resonant cavity. Under electromagnetic irradiation, the temperature rise at various points on the cell samples is suppressed. The cell temperature rise caused by each unit of irradiation dose, such as 1 W / kg of SAR (Specific Absorption Rate, i.e., the electromagnetic power absorbed per unit mass of cell sample), is 0.014℃~0.019℃. When the non-thermal temperature change threshold is set to 0.1℃, the maximum allowable irradiation dose of the experimental system is approximately 5 W / kg. However, such steady temperature control only utilizes positive temperature changes and regulation, without taking advantage of negative temperature changes and regulation, thus limiting the extent to which the maximum allowable irradiation dose can be increased in experiments on the non-thermal effects of electromagnetic irradiation on cells can be improved.
[0005] Modulated temperature control utilizes both positive and negative temperature variations and adjustments. As described in their paper "Adaptive Temperature Control Applied to a 900-MHz In Vitro Exposure Setup for Nonthermal Effects of a High-Level SAR[J].IEEE Transactions on Microwave Theory and Techniques,2022,70(3):1658-1673", Zhao J et al. used an experimental system to generate an adaptive temperature-controlled airflow to cool the cell samples in the TEM resonant cavity. The temperature of the cell samples rose locally and fell locally, with the highest temperature change never exceeding the temperature change threshold of the nonthermal effect and the lowest temperature change never less than the opposite value of the temperature change threshold of the nonthermal effect, thus canceling out the cell temperature rise. Using the average SAR in the cell samples as a reference for the irradiation dose, the modulated temperature control increases the maximum allowable irradiation dose for electromagnetic irradiation cell nonthermal effect experiments by approximately 2.43 times compared to steady-state temperature control. However, the current modulation temperature control is achieved through adaptive temperature control. The airflow temperature change curve generated by adaptive temperature control through multiple iterations will show obvious oscillations in the initial stage of irradiation. The curve shape is complex. Achieving such an airflow temperature change curve requires a lot of experiments and debugging, which is difficult, time-consuming and not feasible. Summary of the Invention
[0006] In order to overcome the shortcomings of the prior art, the present invention aims to provide an exponential cell temperature control method and system for experiments on the non-thermal effects of high-dose electromagnetic irradiation on cells.
[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0008] In a first aspect, the present invention discloses an exponential cell temperature control method for experiments on the non-thermal effects of high-dose electromagnetic irradiation on cells, comprising the following steps:
[0009] S1. Electromagnetic modeling and simulation: Using electromagnetic modeling and simulation software, an electromagnetic parameter model is established for the electromagnetic irradiation experimental device loaded with cell samples, the electromagnetic irradiation experimental process is simulated, the electromagnetic field shape and energy distribution in the electromagnetic irradiation experimental device are obtained, and the SAR distribution data of cell samples and the absorbed power distribution data of sample support medium components are calculated.
[0010] S2. Temperature modeling and simulation: Using temperature modeling and simulation software, a thermodynamic parameter model is established for the cell sample and sample support medium assembly under the action of airflow. Using the SAR distribution data and absorbed power distribution data obtained in S1, the heating, heat conduction and heat exchange with airflow of the cell sample and sample support medium assembly during the electromagnetic irradiation experiment are simulated. The temperature change distribution data of the cell sample at each time moment is calculated to obtain the highest temperature change and lowest temperature change of the cell sample at each time moment.
[0011] S3. Calculation of the upper limit of average SAR: Record the SAR distribution data obtained in S1, and the highest and lowest temperature change curves and their stable values of the cell samples obtained in S2 when the airflow temperature is stable and constant. Based on the ratio of the temperature change threshold of non-thermal effect to the stable value of the highest temperature change, and the proportional relationship between the stable value of the highest temperature change and the average SAR, calculate the upper limit of the average SAR allowed in the non-thermal effect experiment when the stable value of the highest temperature change reaches the temperature change threshold of non-thermal effect under constant temperature control. Based on the proportional relationship between the difference between the stable values of the highest and lowest temperature changes and the average SAR, take the stable values of the highest and lowest temperature changes as the temperature change threshold of non-thermal effect and their opposite values, that is, take the difference between the stable values of the highest and lowest temperature changes as twice the temperature change threshold of non-thermal effect, and calculate the upper limit of the average SAR allowed in the non-thermal effect experiment when the airflow temperature is adjusted over time under modulated temperature control.
[0012] S4. Calculation of the redundancy range of the airflow temperature change curve of the exponential temperature control: The average SAR is taken to be less than the upper limit allowed by the modulated temperature control. The exponential temperature control function is used to generate the airflow temperature change curve of the exponential temperature control. Based on the temperature modeling and simulation of S2, the highest and lowest temperature change curves of the cell sample during the electromagnetic irradiation experiment are calculated. The temperature utilization coefficient and temperature change time constant are adjusted so that the highest temperature change is always no greater than the temperature change threshold of the non-thermal effect, and the lowest temperature change is always no less than the opposite value of the temperature change threshold of the non-thermal effect. In this way, the redundancy range of the airflow temperature change curve of the exponential temperature control required to eliminate the cell temperature rise is obtained under the selected average SAR.
[0013] S5. The implementation of exponential temperature control involves conducting electromagnetic irradiation experiments to generate the average SAR selected in S4 in the cell sample. The airflow temperature near the cell sample is then adjusted so that the airflow temperature change curve falls within the redundancy range of the airflow temperature change curve obtained by exponential temperature control in S4.
[0014] Secondly, this invention discloses an exponential cell temperature control system for experiments on the non-thermal effects of high-dose electromagnetic irradiation on cells, comprising the following functional modules:
[0015] Temperature sensor 100 is used to collect temperature data required by the exponential cell temperature control method and system in experiments on the non-thermal effects of high-dose electromagnetic irradiation on cells. The temperature data includes at least the airflow temperature data near the cell sample.
[0016] The host computer 200 is used to run electromagnetic modeling and simulation software to establish an electromagnetic parameter model of the electromagnetic irradiation experimental device containing cell samples, simulate the electromagnetic irradiation experiment process, obtain the electromagnetic field shape and energy distribution in the electromagnetic irradiation experimental device, and calculate the SAR distribution data of the cell samples and the absorbed power distribution data of the sample support medium assembly. It is also used to run temperature modeling and simulation software to establish a thermodynamic parameter model of the cell samples and sample support medium assembly under airflow. Combined with the SAR distribution data and absorbed power distribution data obtained from the electromagnetic modeling and simulation, it simulates the heating, heat conduction, and heat exchange with the airflow of the cell samples and sample support medium assembly during the electromagnetic irradiation experiment, calculates the temperature change distribution data of the cell samples at various times, and obtains the highest temperature of the cell samples at each time point. It is used to calculate the upper limit of the average SAR allowed in constant and modulated temperature control experiments for non-thermal effects by combining SAR distribution data obtained from electromagnetic modeling simulation and temperature change distribution data obtained from temperature modeling simulation under constant temperature control; it is also used to select the average SAR of cell samples under modulated temperature control, calculate the corresponding upper and lower limits of temperature utilization coefficient, upper and lower limits of temperature change time constant, and the redundancy range of the airflow temperature change curve of exponential temperature control required to counteract cell temperature rise; it is also used to obtain the airflow temperature change curve near the cell sample during the electromagnetic irradiation experiment measured by temperature sensor 100, set and adjust the temperature control parameters so that the measured curve falls within the redundancy range of the airflow temperature change curve of exponential temperature control required to counteract cell temperature rise.
[0017] Temperature control module 300 is used to acquire temperature control parameters generated by host computer 200 and generate temperature control voltage according to temperature control parameters.
[0018] The temperature-controlled airflow generation module 400 is used to generate airflow and to acquire the temperature control voltage generated by the temperature control module 300. The temperature of the airflow is adjusted according to the temperature control voltage. The airflow flows into the electromagnetic irradiation experimental device, flows through the cell sample, exchanges heat with it, and then flows out.
[0019] Preferably, the temperature-controlled airflow generating module 400 includes:
[0020] The semiconductor electric heating pile 401 is used to obtain the temperature control voltage generated by the temperature control module 300, and to perform cooling or heating and adjust the power according to the direction and magnitude of the temperature control voltage.
[0021] Fan 402 is used to generate airflow, which flows through semiconductor heating stack 401 to generate temperature-controlled airflow;
[0022] Insulated tube 403 is used to deliver temperature-controlled airflow into the electromagnetic irradiation experimental device.
[0023] Compared with the prior art, the beneficial effects of the present invention are:
[0024] This invention proposes a novel modulated temperature control, namely exponential temperature control. By performing electromagnetic and temperature modeling simulations of the electromagnetic irradiation experiment, and ensuring the average SAR is less than the upper limit allowed by the modulated temperature control, the redundancy range of the airflow temperature change curve required to counteract cell temperature rise is calculated. The airflow temperature near the cell sample is then adjusted to ensure the airflow temperature change curve falls within this range. During the electromagnetic irradiation experiment, through heat exchange with the airflow, the highest temperature change of the cell sample never exceeds the non-thermal effect temperature change threshold, and the lowest temperature change never falls below the opposite value of the non-thermal effect temperature change threshold. This invention achieves a certain redundancy range for the airflow temperature change curve, significantly improving the feasibility of temperature control. Attached Figure Description
[0025] Figure 1 This is a schematic flowchart of an exponential cell temperature control method for experiments on the non-thermal effects of high-dose electromagnetic irradiation of cells, provided in an embodiment of the present invention.
[0026] Figure 2 This is a schematic diagram of the highest and lowest temperature change curves of cell samples in an embodiment of the present invention; wherein, (a) corresponds to the use of steady-state temperature control and the irradiation dose is SAR. stationary (b) Corresponding to constant temperature control, and the irradiation dose is (c) Corresponding to the use of modulated temperature control, and the irradiation dose is
[0027] Figure 3 This is a schematic diagram showing the redundancy range of the highest and lowest temperature change curves of the cell sample and the airflow temperature change curve when using exponential temperature control in an embodiment of the present invention.
[0028] Figure 4 This is a schematic block diagram of an exponential cell temperature control system for experiments on the non-thermal effects of high-dose electromagnetic irradiation of cells, provided in an embodiment of the present invention.
[0029] Figure 5 This is a schematic block diagram of the temperature-controlled airflow generation module in an exponential cell temperature control system for high-dose electromagnetic irradiation cell non-thermal effect experiments, provided in an embodiment of the present invention.
[0030] Figure 6This is a schematic diagram of a high-dose electromagnetic irradiation cell non-thermal effect experimental system using exponential temperature control, provided in an embodiment of the present invention. Detailed Implementation
[0031] It should be noted that, in this application, the electromagnetic irradiation experimental device is not limited in form (such as TEM chamber, waveguide resonant cavity and antenna, etc.), and at least includes a sample support medium assembly (such as petri dish, petri dish support, etc.) and a signal power source, mainly used in the electromagnetic irradiation band (300MHz to 100GHz) where non-thermal effects are easily interfered with by thermal effects.
[0032] It should also be noted that, in this application, the word “exemplary” is used to indicate that, as an example, illustration or illustration, the use of “exemplary” is intended to present the relevant concepts in an intuitive and concrete manner, and should not be construed as having any advantage over other embodiments or designs.
[0033] The embodiments and effects of the present invention will be further described in detail below with reference to the accompanying drawings:
[0034] like Figure 1 As shown, this embodiment of the invention provides an exponential cell temperature control method for experiments on the non-thermal effects of high-dose electromagnetic radiation on cells, comprising the following steps:
[0035] S1. Electromagnetic modeling and simulation: Using electromagnetic modeling and simulation software, an electromagnetic parameter model is established for the electromagnetic irradiation experimental device loaded with cell samples. The electromagnetic irradiation experimental process is simulated to obtain the electromagnetic field shape and energy distribution in the electromagnetic irradiation experimental device. The SAR distribution data of the cell samples and the absorbed power distribution data of the sample support medium components are calculated.
[0036] For example, the electromagnetic modeling and simulation uses the XFDTD electromagnetic modeling and simulation software based on the Maxwell equations FDTD algorithm to build a CAD model of the electromagnetic irradiation experimental device containing cell samples. The model is adaptively meshed. To balance computational accuracy and efficiency, the culture dish space is meshed into a 0.2 mm grid, and the remaining space into a 1 mm grid. The electromagnetic parameters of each component material in the mesh model (such as conductivity σ and relative permittivity ε) are set. rThe simulation program sets the mass density ρ of the cell sample, the frequency of the signal power source, the incident power (which needs to be converted into the voltage amplitude and internal resistance of the power supply), and the irradiation time. It then simulates the electromagnetic irradiation experiment and outputs the stable electric field amplitude of each grid cell. This data is used to calculate the SAR distribution data of the cell sample and the absorbed power distribution data of the sample support medium assembly. In the cell sample grid, the SAR is calculated from the conductivity σ, mass density ρ, and electric field amplitude at the grid center. XFDTD can directly output the SAR results. In the sample support medium assembly grid, the absorbed power is calculated from the conductivity σ and electric field amplitude at the grid center. XFDTD needs to output the electric field amplitude, and a program needs to be written to calculate the absorbed power.
[0037] S2. Temperature modeling and simulation: Using temperature modeling and simulation software, a thermodynamic parameter model is established for the cell sample and sample support medium assembly under the action of airflow. Using the SAR distribution data and absorbed power distribution data obtained in S1, the heating, heat conduction and heat exchange with airflow of the cell sample and sample support medium assembly during the electromagnetic irradiation experiment are simulated. The temperature change distribution data of the cell sample at each time moment are calculated to obtain the highest and lowest temperature changes of the cell sample at each time moment.
[0038] For example, the temperature modeling simulation employs the FDTD algorithm based on the Pennes biological heat conduction equation. A mesh model of the cell sample and sample support medium assembly is built using S1. Thermodynamic parameters (such as specific heat capacity C and thermal conductivity λ) of each component material in the mesh model are set. The heat exchange between the airflow and the material is set as the thermal conductivity H, which is obtained through experimental measurement. The heat source and airflow temperature are set, and the temperature simulation of the electromagnetic irradiation experiment is performed. The temperature change distribution data of the cell sample at each time point is calculated. At each time point, the highest and lowest temperature changes of the cell sample are found grid by grid. Setting the heat source involves calculating the distribution of heat power using the SAR distribution data and absorbed power distribution data obtained from S1. The heat power of the cell sample mesh is equal to its SAR multiplied by its mass density ρ, and the heat power of the sample support medium assembly mesh is equal to its absorbed power.
[0039] S3. Calculation of the upper limit of average SAR: Record the SAR distribution data obtained in S1, and the highest and lowest temperature change curves and their stable values of the cell samples obtained in S2 when the airflow temperature is stable and constant. Based on the ratio of the non-thermal effect temperature change threshold to the stable value of the highest temperature change, and the proportional relationship between the stable value of the highest temperature change and the average SAR, calculate the upper limit of the average SAR allowed in the non-thermal effect experiment when the stable value of the highest temperature change reaches the non-thermal effect temperature change threshold under constant temperature control. Based on the proportional relationship between the difference between the stable values of the highest and lowest temperature changes and the average SAR, take the stable values of the highest and lowest temperature changes as the non-thermal effect temperature change threshold and its opposite value, that is, take the difference between the stable values of the highest and lowest temperature changes as twice the non-thermal effect temperature change threshold, and calculate the upper limit of the average SAR allowed in the non-thermal effect experiment when the airflow temperature is adjusted over time under modulated temperature control.
[0040] Upper limit of average SAR allowed in steady-state temperature-controlled non-thermal effect experiments The calculation formula is as follows:
[0041]
[0042] In the formula, ΔT th The threshold for temperature change without thermal effects. and SAR stationary These represent the stable value and average SAR of the highest temperature change of the cell sample under constant temperature control.
[0043] Upper limit of average SAR allowed in non-thermal effect experiments under modulated temperature control The calculation formula is as follows:
[0044]
[0045] In the formula, This is the stable value of the lowest temperature change of the cell sample under constant temperature control.
[0046] From Equations 1 and 2, we can deduce that: In other words, compared to steady-state temperature control, modulated temperature control under ideal conditions can at least double the maximum permissible irradiation dose in experiments on the non-thermal effects of electromagnetic irradiation on cells.
[0047] For example, such as Figure 2 As shown in (a) to (c), the horizontal axis represents time t, and the vertical axis represents temperature change. All temperature changes are referenced to the cell culture temperature, including the airflow temperature change ΔT. air (t), the highest and lowest temperature changes of the cell sample under constant temperature control ΔT max,stationary (t), ΔT min,stationary (t) and the highest and lowest temperature changes ΔT of the cell samples during temperature control modulation.max,variable (t), ΔT min,variable (t). (a) is the result of steady-state temperature control, ΔT air (t) = 0, and the irradiation dose is set to SAR. stationary After irradiation begins, ΔT max,stationary (t) and ΔT min,stationary (t) all increase and gradually stabilize, ΔT max,stationary (t) stabilizes to (b) As the result remains a steady-state temperature control, the irradiation dose is changed to the upper limit. ΔT max,stationary (t) and ΔT min,stationary The height of (t) varies proportionally with the irradiation dose, and (c) is the result of temperature control adjustment, ΔT air (t) jumps from 0 to a negative value at the start of irradiation, with the irradiation dose set to the upper limit. After irradiation begins, ΔT max,variable (t) rises and then stabilizes, with a stable value of t. ΔT min,variable (t) decreases and then stabilizes, with a stable value of t. It should be noted that (c) represents the result of ideal temperature control; in reality, ΔT air (t) cannot step, only at the irradiation dose SAR variable Less than At that time, a gradual temperature control function, such as an exponential temperature control function, is used to generate an airflow temperature change curve to obtain the result of exponential temperature control.
[0048] S4. Calculation of the redundancy range of the airflow temperature change curve for exponential temperature control: The average SAR is taken to be less than the upper limit allowed by the modulated temperature control. An exponential temperature control function is used to generate the airflow temperature change curve for exponential temperature control. Based on temperature modeling and simulation in S2, the highest and lowest temperature change curves of the cell sample during the electromagnetic irradiation experiment are calculated. The temperature utilization coefficient and temperature change time constant are adjusted so that the highest temperature change is never greater than the non-thermal effect temperature change threshold, and the lowest temperature change is never less than the opposite value of the non-thermal effect temperature change threshold. This yields the redundancy range of the airflow temperature change curve for exponential temperature control required to offset cell temperature rise under the selected average SAR.
[0049] The exponential temperature control function is as follows:
[0050]
[0051] In the formula, t is time, t≥0, K is the temperature utilization coefficient, K≥1, τ is the temperature change time constant, τ>0, and SAR variable This represents the average SAR of the cell sample under variable temperature control.
[0052] For example, such as Figure 3 As shown, the horizontal axis represents time t, and the vertical axis represents temperature change. All temperature changes are referenced to the cell culture temperature, including the gas flow temperature change ΔT. air (t), and the highest and lowest temperature changes ΔT of the cell sample under temperature control. max,variable (t), ΔT min,variable (t), ΔT air (t) Take an exponential temperature control function, and set the irradiation dose as SAR. variable Slightly below the upper limit After irradiation begins, ΔT max,variable (t) rises to a peak It then dropped and stabilized. ΔT min,variable (t) rises slightly, then falls and stabilizes. If the temperature utilization coefficient K is taken as its lower limit K min =1, then It increases with the increase of the temperature change time constant τ. Increase to ΔT th When the lower bound τ is obtained min ΔT min,variable (t) is always greater than -ΔT th When τ is greater than τ min When K increases accordingly, Reduce to ΔT th Meanwhile, ΔT min,variable (t) decreases; τ continues to increase, and K continues to increase accordingly until... equal to -ΔT th When, the upper limit τ is obtained. max The upper limit of K max The ranges of K and τ provide the redundancy range of the airflow temperature variation curve; the size of the redundancy range is related to the SAR. variable The selection of SAR is related. variable The closer The smaller the redundancy range, the better the SAR variable The further away The larger the redundancy range.
[0053] S5. The implementation of exponential temperature control involves conducting electromagnetic irradiation experiments to generate the average SAR selected in S4 in the cell sample. The airflow temperature near the cell sample is then adjusted so that the airflow temperature change curve falls within the redundancy range of the airflow temperature change curve obtained by exponential temperature control in S4.
[0054] For example, within the redundancy range of the airflow temperature change curve, the median of the redundancy interval at each time point is taken at equal time intervals, and the medians are connected to obtain the target curve approximated by a piecewise linear curve. For each piecewise linear curve, a proportional-integral-differential algorithm is used to adjust the direction and magnitude of the temperature control voltage of the semiconductor heating pile according to the airflow temperature near the cell sample measured by the temperature sensor, so that the airflow temperature change curve approaches the target curve and falls within the redundancy range.
[0055] like Figure 4 As shown, this embodiment of the invention provides an exponential cell temperature control system for experiments on the non-thermal effects of high-dose electromagnetic irradiation on cells, used to execute the above-described exponential cell temperature control method, and includes the following functional modules:
[0056] Temperature sensor 100 is used to collect temperature data required by the exponential cell temperature control method and system in experiments on the non-thermal effects of high-dose electromagnetic irradiation on cells. The temperature data includes at least the airflow temperature data near the cell sample.
[0057] The host computer 200 is used to run electromagnetic modeling and simulation software to establish an electromagnetic parameter model of the electromagnetic irradiation experimental device containing cell samples, simulate the electromagnetic irradiation experiment process, obtain the electromagnetic field shape and energy distribution in the electromagnetic irradiation experimental device, and calculate the SAR distribution data of the cell samples and the absorbed power distribution data of the sample support medium assembly. It is also used to run temperature modeling and simulation software to establish a thermodynamic parameter model of the cell samples and sample support medium assembly under airflow. Combined with the SAR distribution data and absorbed power distribution data obtained from the electromagnetic modeling and simulation, it simulates the heating, heat conduction, and heat exchange with the airflow of the cell samples and sample support medium assembly during the electromagnetic irradiation experiment, calculates the temperature change distribution data of the cell samples at various times, and obtains the highest temperature of the cell samples at each time point. It is used to calculate the upper limit of the average SAR allowed in constant and modulated temperature control experiments for non-thermal effects by combining SAR distribution data obtained from electromagnetic modeling simulation and temperature change distribution data obtained from temperature modeling simulation under constant temperature control; it is also used to select the average SAR of cell samples under modulated temperature control, calculate the corresponding upper and lower limits of temperature utilization coefficient, upper and lower limits of temperature change time constant, and the redundancy range of the airflow temperature change curve of exponential temperature control required to counteract cell temperature rise; it is also used to obtain the airflow temperature change curve near the cell sample during the electromagnetic irradiation experiment measured by temperature sensor 100, set and adjust the temperature control parameters so that the measured curve falls within the redundancy range of the airflow temperature change curve of exponential temperature control required to counteract cell temperature rise.
[0058] Temperature control module 300 is used to acquire temperature control parameters generated by host computer 200 and generate temperature control voltage according to temperature control parameters.
[0059] The temperature-controlled airflow generation module 400 is used to generate airflow and to acquire the temperature control voltage generated by the temperature control module 300. The temperature of the airflow is adjusted according to the temperature control voltage. The airflow flows into the electromagnetic irradiation experimental device, flows through the cell sample, exchanges heat with it, and then flows out.
[0060] In this system, such as Figure 5 As shown, the temperature-controlled airflow generation module 400 includes: a semiconductor heating stack 401, used to acquire the temperature control voltage generated by the temperature control module 300, and to perform cooling or heating and adjust the power according to the direction and magnitude of the temperature control voltage; a fan 402, used to generate airflow, which flows through the semiconductor heating stack 401 to generate temperature-controlled airflow; and an insulation tube 403, used to send the temperature-controlled airflow into the electromagnetic irradiation experimental device.
[0061] For example, a high-dose electromagnetic irradiation cell non-thermal effect experimental system employing exponential temperature control is as follows: Figure 6 As shown in the figure, the dashed box represents the exponential cell temperature control system 1 of the present invention for experiments on the non-thermal effects of high-dose electromagnetic radiation on cells, and the arrows indicate the airflow direction. Figure 6 In the experimental system shown, the resonant cavity 2 is placed horizontally. A pair of sample support media assemblies 3 horizontally fix a pair of culture dishes 4 containing cell samples inside the resonant cavity 2, located at the point of maximum magnetic field. The resonant cavity 2 is a rectangular waveguide resonant cavity with an operating frequency of 1.8 GHz, and the culture dishes 4 have a diameter of 35 mm. An RF connector 5 is installed at the center above the resonant cavity 2, with its outer conductor short-circuited to the cavity and its inner conductor connected to a feed probe inserted into the cavity 2. The RF connector 5 is connected to a signal power source 7 via a coaxial line 6, feeding electromagnetic signals and power into the resonant cavity 2, exciting an electromagnetic field. The cell samples absorb the electromagnetic power, resulting in SAR (Specific Absorption Regulator). The resonant cavity 2 has 40 mm diameter vents 8 at both ends and directly above the culture dishes 4, which are electromagnetically shielded using an 8-mesh copper mesh. A pair of temperature sensors 100 are placed near the vents 8 of the resonant cavity 2, outside the copper mesh, to measure the temperature of the inflow and outflow airflow, taking the average value as the airflow temperature near the cell samples. The host computer 200 and the temperature control module 300 control the temperature control airflow generation module 400 to generate airflow. The airflow flows into the resonant cavity 2 through the air holes 8 at both ends, exchanges heat with the cell sample, and then flows out through the air hole 8 at the top.
[0062] The above description is a specific embodiment of the present invention and does not set any limitation on the present invention. The implementation of the present invention is not limited to the above-described manner. Any changes or substitutions made without departing from the principle of the present invention should be regarded as equivalent substitutions and should be included within the protection scope of the present invention.
Claims
1. An exponential cell temperature control method for experiments on the non-thermal effects of high-dose electromagnetic radiation on cells, characterized in that, Includes the following steps: S1, Electromagnetic Modeling and Simulation Electromagnetic modeling and simulation software was used to establish an electromagnetic parameter model for an electromagnetic irradiation experimental device loaded with cell samples, simulate the electromagnetic irradiation experimental process, obtain the electromagnetic field pattern and energy distribution in the electromagnetic irradiation experimental device, and calculate the SAR distribution data of cell samples and the absorbed power distribution data of the sample support medium components. S2, Temperature Modeling and Simulation Using temperature modeling simulation software, a thermodynamic parameter model was established for the cell sample and sample support medium assembly under the action of airflow. Using the SAR distribution data and absorbed power distribution data obtained from S1, the heating, heat conduction and heat exchange with airflow of the cell sample and sample support medium assembly during the electromagnetic irradiation experiment were simulated. The temperature change distribution data of the cell sample at each time was calculated, and the highest and lowest temperature changes of the cell sample at each time were obtained. S3, Calculation of the upper limit of average SAR Record the SAR distribution data obtained in S1, and the highest and lowest temperature change curves and their stable values of the cell samples obtained in S2 when the airflow temperature is stable and constant. Based on the ratio of the non-thermal effect temperature change threshold to the stable value of the highest temperature change, and the proportional relationship between the stable value of the highest temperature change and the average SAR, calculate the upper limit of the average SAR allowed in the non-thermal effect experiment when the stable value of the highest temperature change reaches the non-thermal effect temperature change threshold under constant temperature control. Based on the proportional relationship between the difference between the stable values of the highest and lowest temperature changes and the average SAR, take the stable values of the highest and lowest temperature changes as the non-thermal effect temperature change threshold and their opposite values, that is, take the difference between the stable values of the highest and lowest temperature changes as twice the non-thermal effect temperature change threshold, and calculate the upper limit of the average SAR allowed in the non-thermal effect experiment when the airflow temperature is adjusted over time under modulated temperature control. S4. Calculation of the redundancy range of the airflow temperature change curve for exponential temperature control. If the average SAR is less than the upper limit allowed by the modulated temperature control, the exponential temperature control function is used to generate the airflow temperature change curve of the exponential temperature control. Based on the temperature modeling and simulation of S2, the highest and lowest temperature change curves of the cell sample during the electromagnetic irradiation experiment are calculated. The temperature utilization coefficient and the temperature change time constant are adjusted so that the highest temperature change is never greater than the temperature change threshold of the non-thermal effect, and the lowest temperature change is never less than the opposite value of the temperature change threshold of the non-thermal effect. In this way, the redundancy range of the airflow temperature change curve of the exponential temperature control required to eliminate the cell temperature rise is obtained under the selected average SAR. S5, Implementation of Exponential Temperature Control Electromagnetic irradiation experiments were conducted to generate the average SAR selected by S4 in the cell sample. The airflow temperature near the cell sample was adjusted so that the airflow temperature change curve fell within the redundancy range of the exponential temperature control airflow temperature change curve obtained by S4. The upper limit of the average SAR allowed by the steady-state temperature-controlled non-thermal effect experiment The calculation formula is as follows: In the formula, The threshold for temperature change without thermal effects. and These represent the stable value and average SAR of the highest temperature change of cell samples under steady-state temperature control, respectively. The upper limit of the average SAR allowed in the non-thermal effect experiment under modulated temperature control. The calculation formula is as follows: In the formula, This is the stable value of the lowest temperature change of the cell sample under constant temperature control. The exponential temperature control function is: In the formula, The airflow temperature change curve is for exponential temperature control. t For time, , K Temperature utilization coefficient, , The temperature change time constant, , This represents the average SAR of the cell sample under variable temperature control.
2. The exponential cell temperature control method for experiments on the non-thermal effects of high-dose electromagnetic radiation on cells according to claim 1, characterized in that, In step S1, a CAD model of the electromagnetic irradiation experimental device loading cell samples is constructed and adaptively divided into a mesh model. Within the mesh of the cell samples, SAR is determined by the electrical conductivity of the constituent materials. σ Mass density ρ The calculation of the electric field amplitude at the center of the grid, within the grid of the sample-supporting medium assembly, shows that the absorbed power is determined by the conductivity of its constituent materials. σ Calculation of electric field amplitude at the grid center.
3. The exponential cell temperature control method for experiments on the non-thermal effects of high-dose electromagnetic irradiation of cells according to claim 2, characterized in that, In step S2, using the mesh model obtained in S1, the thermodynamic parameters of each component material in the mesh model are set, the heat source and airflow temperature are set, and temperature simulation of the electromagnetic irradiation experiment process is performed to calculate the temperature change distribution data of the cell sample at each time moment. At each time moment, the highest and lowest temperature changes of the cell sample are found grid by grid. Setting the heat source means using the SAR distribution data and absorbed power distribution data obtained in S1 to calculate the distribution of heat power. The heat power of the cell sample mesh is equal to its SAR multiplied by its mass density. ρ The heat generation power of the sample support medium assembly grid is equal to its absorbed power.
4. The exponential cell temperature control method for experiments on the non-thermal effects of high-dose electromagnetic radiation on cells according to claim 1, characterized in that, In step S5, within the redundant range of the airflow temperature change curve, the median value of the redundant interval at each time point is taken at equal time intervals, and the median values are connected to obtain the target curve approximated by a broken line. For each broken line segment, a proportional-integral-differential algorithm is used to adjust the direction and magnitude of the temperature control voltage of the semiconductor electric heating pile according to the airflow temperature near the cell sample measured by the temperature sensor, so that the airflow temperature change curve approaches the target curve and falls within the redundant range.
5. An exponential cell temperature control system for conducting experiments on the non-thermal effects of high-dose electromagnetic irradiation of cells, used to implement the method described in any one of claims 1-4, characterized in that, Includes the following functional modules: Temperature sensor (100) is used to collect temperature data required by the exponential cell temperature control method and system in the experiment of non-thermal effects of high-dose electromagnetic irradiation of cells, wherein the temperature data includes at least the airflow temperature data near the cell sample. The host computer (200) is used to run electromagnetic modeling and simulation software to establish an electromagnetic parameter model for the electromagnetic irradiation experimental device loaded with cell samples, simulate the electromagnetic irradiation experimental process, obtain the electromagnetic field shape and energy distribution in the electromagnetic irradiation experimental device, and calculate the SAR distribution data of the cell samples and the absorbed power distribution data of the sample support medium component. It is also used to run temperature modeling and simulation software to establish a thermodynamic parameter model for the cell samples and sample support medium component under airflow. Combined with the SAR distribution data and absorbed power distribution data obtained from the electromagnetic modeling and simulation, it simulates the heating, heat conduction, and heat exchange with the airflow of the cell samples and sample support medium component during the electromagnetic irradiation experiment, calculates the temperature change distribution data of the cell samples at various times, and obtains the highest temperature of the cell samples at each time point. Temperature change and minimum temperature change; also used to combine the SAR distribution data obtained from electromagnetic modeling simulation and the temperature change distribution data obtained from temperature modeling simulation under steady temperature control, to calculate the upper limit of the average SAR allowed in the non-thermal effect experiment under steady and modulated temperature control; also used to select the average SAR of the cell sample under modulated temperature control, to calculate the upper and lower limits of the corresponding temperature utilization coefficient, the upper and lower limits of the temperature change time constant, and the redundancy range of the airflow temperature change curve of the exponential temperature control required to cancel the cell temperature rise; also used to obtain the airflow temperature change curve near the cell sample during the electromagnetic irradiation experiment measured by the temperature sensor (100), to set and adjust the temperature control parameters so that the measured curve falls within the redundancy range of the airflow temperature change curve of the exponential temperature control required to cancel the cell temperature rise. The temperature control module (300) is used to acquire the temperature control parameters generated by the host computer (200) and generate a temperature control voltage based on the temperature control parameters. The temperature-controlled airflow generation module (400) is used to generate airflow and to acquire the temperature control voltage generated by the temperature control module (300). The temperature of the airflow is adjusted according to the temperature control voltage. The airflow flows into the electromagnetic irradiation experimental device, flows through the cell sample, exchanges heat with it, and then flows out.
6. The exponential cell temperature control system for experiments on the non-thermal effects of high-dose electromagnetic irradiation of cells according to claim 5, characterized in that, The temperature-controlled airflow generating module (400) includes: The semiconductor electric heating pile (401) is used to obtain the temperature control voltage generated by the temperature control module (300), and to perform cooling or heating and adjust the power according to the direction and magnitude of the temperature control voltage; A fan (402) is used to generate airflow, which flows through a semiconductor heating element (401) to produce temperature-controlled airflow; Insulated tube (403) is used to deliver temperature-controlled airflow into the electromagnetic irradiation experimental device.