Electromagnetic Biology and Medicine最新文献

A highly miniaturized planar monopole antenna is presented for biomedical applications. The proposed antenna utilizes polydimethylsiloxane (PDMS) with dielectric constant 2.7 and loss tangent 0.0314 with thickness 0.3 mm as substrate and with thickness 0.2 mm as superstrate. A copper foil of 0.03 mm thickness is used for radiating elements. The proposed structure contains a unique structure, made of loop-based structure with three rectangular-shaped stubs are added to tune the operating frequency to 5.8 GHz and to improve the reflection coefficient. The incorporation of stubs achieved the intended frequency of operation, utilization of the loop-based structure for designing the antenna achieved high miniaturization. The proposed antenna is analyzed under various conditions like under skin, muscle, stomach, small intestine,, colon etc., and comparative analysis is presented with the help of reflection coefficient, radiation patterns and specific absorption rate (SAR). SAR is evaluated over a volume of 1 g tissue as per the standards of Federal Communications Commission (FCC). SAR value of the antenna is below 1.6 W/kg for input power 1.9 mW. The simulated analysis showed that the designed antenna is suitable for both implantable and endoscopic applications. Moreover the simulated and measured analysis for reflection coefficient of the proposed antenna showed good agreement.

This study aimed to evaluate the effect of Pulsed Electromagnetic Fields (PEMF) in improving blood flow reduction and tissue necrosis of ischemic animal induced by skin flap. In each experiment, twenty rats (280-320 g) were randomly divided into control group (n = 10) and PEMF (n = 10) group. All of the rats were performed skin flap in back. In the PEMF group, PEMF (1 Hz, 10 mT) was performed in each experiment. In Experiment-1 (n = 20), PEMF was performed for 90 minutes. In Experiment-2 (n = 20), additionally, a blocking film was inserted, and suture was performed to induce necrosis. PEMF was performed for 30 minutes each day for 7 days. As a result of Speckle-Flow Index (SFI) analysis, in the control group, blood flow continued to decrease immediately after the procedure. In the PEMF group, blood flow was remained constant after 30 minutes and increased after 60 minutes. The blood flow in a specific region substantially increased from the initial state. As a result of skin necrosis analysis, the progression rate in the PEMF group was slower than that of the control group. The rate of necrosis in the PEMF group decreased dramatically from the 6th day, and there was a statistically significant difference between the two groups at the 7th day (p < .05). In this study, it was confirmed that PEMF (1 Hz, 10 mT) has a blood flow improvement and skin tissue necrosis alleviation in the ischemic flap animal model.

This study distinguishes the design and analysis of a coaxial probe for measurement of biological body dielectric properties, in this measurement estimating the human tissue-equivalent liquid (TEL) permittivity and conductivity, to monitor and maintain the international standards for specific absorption rate (SAR) evaluation over the frequency band of 800 MHz-5 GHz. In addition, deionized (DI) water and ethanediol dielectric properties have been evaluated and the designed probe results compared to the commercial Dielectric Assessment kit (DAK) 3.5 probe. The obtained results are in good agreement with each other, moreover, the SAR calculation and each source of uncertainty budget analysis are estimated. Therefore, this fabricated probe may be suitable for liquid dielectric properties measurement.

Electrical Pulsed Field (PEF), of pulse duration in 4 milliseconds, effect on mosquito larvae (Culex pipiens) as aquatic insects is assessed in this work. Mosquito larvae classes have been treated with electric field power values (66.66, 83.33, 100, 116.66 V/cm) with separate pulse number (60) and other classes of various pulse numbers have been treated (20, 40, 60, 80) with power of the electrical field 100 V/cm. The findings revealed that positively significant of increase of the applied electrical field strength or increase of the number of pulses. The rise in both cases leads to an increase in the mortality of 25%, 50%, and 75% of the mosquito larvae (P < .05). The impact was calculated with the bioassay system on mosque larvae, SDS-PAGE for whole body proteins, enzyme analysis and ultrastructural examination using TEM. The current study reveals that a low pulsed electric field can cause mosquito larvae genotoxic, changes in the insect's body proteins, which may affect the insect's ability to live. The increase in pulsed electric field parameters also activates oxidative stress in the insect cell by disrupting its secretion of enzymes that could affect the mosquito's capabilities in the future.

Electrochemotherapy (ECT) as a tumor treatment modality is approved for cutaneous and subcutaneous tumors. The purpose of the present study was to examine the effect of 900 MHz radiofrequency (RF) pulse-modulated by 217 Hz EMFs similar to those emitted by mobile phones on the mechanisms of ECT in vivo including: tumor hypoxia and immune system response, and on tumor volume.4 T1 cells were injected subcutaneously into the right flank of Balb/c mice. The mice were exposed to RF fields at specific absorption rate (SAR) 2 W/kg for 10 min/day and then treated with ECT. Two protocols of ECT were used: ((70 V/cm-5 kHz) and 70 V/cm-4 kHz)). Tumor hypoxia was analyzed through HIF-1α immuonohistochemistry assay. Interleukin 4 (IL-4) and IFN-γ levels were estimated by enzyme-linked immunosorbent assay (ELISA) technique to evaluate immune system response. Also, tumors volume changes were measured for 24 days following the treatment. The results showed that pulse-modulated RF fields could increase hypoxia induced by ECT, significantly (about 13% in ECT (70 V/cm-5 kHz) and 11% in ECT (70 V/cm-4 kHz)). However, these fields did not have significant effect on immune system response (the levels of IL-4 and IFN-γ) and tumor volume changes induced by ECT. Our results indicated that pulse-modulated RF fields could not affect tumor volume changes in ECT with the frequency of 5 kHz and voltage of 70 V/cm efficacy in vivo. However, investigating the role of other environmental intervening factors on this protocol of ECT is recommended in further studies.

Although the evidence is inconclusive, epidemiological studies strongly suggest that increased exposure to electromagnetic radiation (EMR) increases the risk of brain tumors, parotid gland tumors, and seminoma. The International Agency for Research on Cancer (IARC) has classified mobile phone radiofrequency radiation as possibly carcinogenic to humans (Group 2B). Humans being are inadvertently being exposed to EMR as its prevalence increases, mainly through mobile phones. Radiation exposure is unavoidable in the current context, with mobile phones being an inevitable necessity. Prudent usage of medicinal plants with a long history of mention in traditional and folklore medicine and, more importantly, are safe, inexpensive, and easily acceptable for long-term human use would be an appealing and viable option for mitigating the deleterious effects of EMR. Plants with free radical scavenging, anti-oxidant and immunomodulatory properties are beneficial in maintaining salubrious health. Green tea polyphenols, Ginkgo biloba, lotus seedpod procyanidins, garlic extract, Loranthus longiflorus, Curcuma amada, and Rosmarinus officinalis have all been shown to confer neuroprotective effects in validated experimental models of study. The purpose of this review is to compile for the first time the protective effects of these plants against mobile phone-induced neuronal damage, as well as to highlight the various mechanisms of action that are elicited to invoke the beneficial effects.

Malignant tumor treatment remains a big challenge till now, and expanding literature indicated that pulsed electromagnetic fields (PEMF) is promising in tumor treatment with the advantage of safety and being economical, but it is still controversial on whether PEMF could affect the tumor cell viability. Therefore, we conducted the meta-analysis to evaluate effects of PEMF on tumor cell viability. The PubMed, EMBASE, Web of Science, and Cochrane Library databases were searched for studies published up to February 2021. Studies on the direct effects of PEMF on tumor cell viability, determined using colorimetric analysis, were included. Two authors extracted the data and completed the quality assessment. A meta-analysis was performed to calculate the absorbance values and 95% confidence intervals (CIs) using random-effects models. Seven studies, including 32 randomized controlled experiments, were analyzed. Compared with the control group, tumor cell viability in the PEMF exposure group was obviously lower (SMD, -0.67; 95% CI: -1.12 to -0.22). The subgroup meta-analysis results showed that PEMF significantly reduced epithelial cancer cell viability (SMD, -0.58; 95% CI: -0.92 to -0.23) but had no influence on stromal tumor cell viability (SMD, -0.93; 95% CI: -0.21 to 0.15). Our study demonstrated that PEMF could inhibit tumor cell proliferation to some extent, but the risk of bias and high heterogeneity (I² > 75%) weakened the strength of the conclusions drawn from the analysis.

We compare the effects of an extremely low-frequency electromagnetic field (EMF) with the chemotherapeutic agent doxorubicin (DOX) on tumor growth and the hepatic redox state in Walker-256 carcinosarcoma-bearing rats. Animals were divided into five groups with one control (no tumor) and four tumor-bearing groups: no treatment, DOX, DOX combined with EMF and EMF. While DOX and DOX + EMF provided greater inhibition of tumor growth, treatment with EMF alone resulted in some level of antitumor effect (p < .05). Superoxide dismutase, catalase activity and glutathione content were significantly decreased in the liver of tumor-bearing animals as compared with the control group (p < .05). The decreases in antioxidant defenses accompanied histological findings of suspected liver damage. However, hepatic levels of thiobarbituric acid reactive substances, an indicator of lipid peroxidation, were three times lower in EMF and DOX + EMF groups than in no treatment and DOX (p < .05). EMF and DOX + EMF showed significantly lower activity of serum ALT than DOX alone (p < .05). These results indicate that EMF treatment can inhibit tumor growth, causing less pronounced oxidative stress damage to the liver. Therefore, EMF can be used as a therapeutic strategy to influence the hepatic redox state and combat cancer with reduced side-effects.

Renal denervation transmits radiofrequency (RF) energy through an electrode to treat resistant hypertension (RH), applying ablation in the renal artery. Several experimental studies have shown that this treatment has been used effectively to treat RH. The aim of this paper is to investigate the effect of ablation parameters (i.e., electrode length, applied voltage, ablation time, and blood flow) on the temperature distribution using a balloon-based array electrodes system. A simplified three-dimensional model including four electrodes and a balloon was established. The balloon diameter was 3 mm and placed in a 5 mm diameter renal artery for forming intra-arterial occlusion. Four electrodes were mounted on the balloon and distributed in the same plane to mimic circumferential RF ablation. Computer simulations were conducted to investigate the thermal performances of the device by setting different electrode configurations, treatment protocols, and physiological factors. The thermal performances including the thermal distribution, maximum lesion depth, length, and area were analyzed. The lesion shape of the array RF electrodes was approximately a sphere with a 100% circumference coverage rate of the renal artery. The lesion depth and length increase with each factor except for blood velocity. Increasing the electrode length from 2 to 4 mm or 2 to 6 mm, the lesion depth increases by 1.15 mm and 0.54 mm at 60 s. The corresponding lesion length increases by 2.65 mm and 2.34 mm, respectively. The range of effective lesion depth is 1.90-4.90 mm, at a voltage of 15-30 V. But the peak temperature at the arterial outer wall exceeded 100 °C when the voltage is above 25 V. In tissue, the degree of thermal injury in the 2 mm area reached 100%, but in blood was not more than 5%. There was no significant difference at different flow conditions because the difference value in lesion depth was not exceeded 0.5 mm. The results showed that the balloon-based four electrodes system is expected to overcome the difficulty of incomplete ablation. In clinical application, 2 mm-electrode is recommended to avoid long wall damage as much as possible and control the voltage below 25 V. This treatment has little thermal injury on the blood, which means it may avoid coagulation formation. Moreover, the application of this device does not need to consider the difference in individual blood velocity.

This study enumerates the quantitative measurement of optical parameters used in several diagnostic procedures for malignant tissue. Optical diagnosis is proposed due to its non-invasive and non-destructive nature. This paper recapitulates Fresnel equation (polarization independent) to determine the characteristic critical angle of malignant tissue. The critical angle of malignant tissue is lower than healthier tissue and is therefore an optical parameter of interest for lesion tissue diagnosis. Similarly, a quantitative analysis is derived to commensurate refractive index and absorption and reflective property of tissue and its nuance with healthier counterparts. The second dichotomy of the research concentrates on comparing and validating the mathematical analysis with COMSOL Multiphysics® 5.2 simulation. The magnitude of malignant tissue reflectance is obtained across a range of incident angle ranging from 0° to 90°. The simulation results satiate the quantitative analysis with only 1.3% deviation. This quantitative result provides prospect of collaborating bio-electromagnetism results with Artificial Intelligence technology for active disease progression diagnosis utilizing minimum invasive diagnostic procedure.