An implantable electrode based on bioresorbable Mg-Nd-Zn-Zr alloy was developed for next-generation radiofrequency (RF) tissue welding application, aiming to reduce thermal damage and enhance anastomotic strength. The Mg alloy electrode was designed with different structural features of cylindrical surface (CS) and continuous long ring (LR) in the welding area, and the electrothermal simulations were studied by finite element analysis (FEA). Meanwhile, the temperature variation during tissue welding was monitored and the anastomotic strength of welded tissue was assessed by measuring the avulsion force and burst pressure. FEA results showed that the mean temperature in the welding area and the proportion of necrotic tissue were significantly reduced when applying an alternating current of 110 V for 10 s to the LR electrode. In the experiment of tissue welding ex vivo, the maximum and mean temperatures of tissues welded by the LR electrode were also significantly reduced and the anastomotic strength of welded tissue could be obviously improved. Overall, an ideal welding temperature and anastomotic strength which meet the clinical requirement can be obtained after applying the LR electrode, suggesting that Mg-Nd-Zn-Zr alloy with optimal structure design shows great potential to develop implantable electrode for next-generation RF tissue welding application.

In the field of ultra-high field MR imaging, the challenges associated with higher frequencies and shorter wavelengths necessitate rigorous attention to multichannel array design. While the need for such arrays remains, and efforts to increase channel counts continue, a persistent impediment-inter-element coupling-constantly hinders development. This coupling degrades current and field distribution, introduces noise correlation between channels, and alters the frequency of array elements, affecting image quality and overall performance. The goal of optimizing ultra-high field MRI goes beyond resolving inter-element coupling and includes significant safety considerations related to the design changes required to achieve high-impedance coils. Although these coils provide excellent isolation, the higher impedance needs special design changes. However, such changes pose a significant safety risk in the form of strong electric fields across low-capacitance lumped components. This process may raise Specific Absorption Rate (SAR) values in the imaging subject, increasing power deposition and, as a result, the risk of tissue heating-related injury. To balance the requirement of inter-element decoupling with the critical need for safety, we suggest a new solution. Our method uses high-dielectric materials to efficiently reduce electric fields and SAR values in the imaging sample. This intervention tries to maintain B1 efficiency and inter-element decoupling within the existing array design, which includes high-impedance coils. Our method aims to promote the full potential of ultra-high field MRI by alleviating this critical safety concern with minimal changes to the existing array setup.

Radio frequency (RF) heating has been proved an alternative roasting method for peanuts, which could effectively degrade aflatoxins and possesses the advantages of greater heating efficiency and penetration depth. This study aimed to investigate the influences of RF roasting on the lipid profile of peanut oil under 150 °C target temperature with varied peanut moisture contents (8.29 % and 20 %) and holding times (0, 7.5, and 15 min), using ultra-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UPLC-QTOF-MS/MS)-based lipidomics. In total, 2587 lipid species from 35 subclasses were identified. After roasting, the contents of sterol lipid (ST) and subclasses of glycerophospholipids (GPs) and glycoglycerolipids increased significantly, while fatty acid (FA), Oxidized (Ox-) FA, cholesterol (CE), and all subclasses of glycerolipids (GLs) decreased, and 1084 differential lipids were screened. The highest ST and lowest CE contents in peanut oil were achieved by medium roasting (7.5 min). The raise in moisture content of peanut simply affected a few GPs subclasses adversely. Compared with hot air (HA) roasting, RF decelerated lipid oxidation, showing higher levels of diacylglycerol, triacylglycerol and FA, with no additional negative impact and only 69 exclusive differential lipids. During RF roasting, hydrolysis and oxidation of fatty acyl chains into secondary oxides were the central behaviors of lipids transformation. This study could provide insights into the lipid changes and transformation mechanism of peanut oil by RF roasting processing.

Wearable sensors are rapidly gaining influence in the diagnostics, monitoring, and treatment of disease, thereby improving patient outcomes. In this review, we aim to explore how these advances can be applied to magnetic resonance imaging (MRI). We begin by (i) introducing limitations in current flexible/stretchable RF coils and then move to the broader field of flexible sensor technology to identify translatable technologies. To this goal, we discuss (ii) emerging materials currently used for sensor substrates, (iii) stretchable conductive materials, (iv) pairing and matching of conductors with substrates, and (v) implementation of lumped elements such as capacitors. Applicable (vi) fabrication methods are presented, and the review concludes with a brief commentary on (vii) the implementation of the discussed sensor technologies in MRI coil applications. The main takeaway of our research is that a large body of work has led to exciting new sensor innovations allowing for stretchable wearables, but further exploration of materials and manufacturing techniques remains necessary, especially when applied to MRI diagnostics.

To provide diverse in-home services like elderly care, versatile activity recognition technology is essential. Radio-based methods, including WiFi CSI, RFID, and backscatter communication, are preferred due to their minimal privacy intrusion, reduced physical burden, and low maintenance costs. However, these methods face challenges, including environmental dependence, proximity limitations between the device and the user, and untested accuracy amidst various radio obstacles such as furniture, appliances, walls, and other radio waves. In this paper, we propose a frequency-shift backscatter tag-based in-home activity recognition method and test its feasibility in a near-real residential setting. Consisting of simple components such as antennas and switches, these tags facilitate ultra-low power consumption and demonstrate robustness against environmental noise because a context corresponding to a tag can be obtained by only observing frequency shifts. We implemented a sensing system consisting of SD-WiFi, a software-defined WiFi AP, and physical switches on backscatter tags tailored for detecting the movements of daily objects. Our experiments demonstrate that frequency shifts by tags can be detected within a 2 m range with 72% accuracy under the line of sight (LoS) conditions and achieve a 96.0% accuracy (F-score) in recognizing seven typical daily living activities with an appropriate receiver/transmitter layout. Furthermore, in an additional experiment, we confirmed that increasing the number of overlaying packets enables frequency shift-detection even without LoS at distances of 3-5 m.

暂无摘要。

In magnetic resonance examination, the interaction between implants and the radio frequency (RF) fields induces heating in human tissue and may cause tissue damage. To assess the RF-induced heating of implants, three steps should be executed, including electromagnetic model construction, electromagnetic model validation, and virtual human body simulations. The crucial step of assessing RF-induced heating involves the construction of a test environment for electromagnetic model validation. In this study, a hardware environment, comprised of a RF generation system, electromagnetic field measurement system, and a robotic arm positioning system, was established. Furthermore, an automated control software environment was developed using a Python-based software development platform to enable the creation of a high-precision automated integrated test environment. The results indicate that the electric field generated in this test environment aligns well with the simulated electric field, making it suitable for assessing the RF-induced heating effects of implants.
在磁共振检查中，植入物与射频场相互作用会引起周围人体组织发热，甚至造成组织损伤。评估植入物射频热效应需要进行植入物电磁建模、电磁模型验证和虚拟人体仿真。其中，构建用于电磁模型验证的测试环境是射频热效应评估的重要环节。研究建立了包括射频发生系统、电磁场量测系统和机械臂定位系统的硬件环境，使用基于Python的软件开发平台实现了自动化控制软件环境，形成了高精度、自动化的集成测试环境。研究结果表明，该测试环境形成的电场与计算机仿真得到的电场具有较好的一致性，可以用于植入物射频热效应评估。.

Mild whole-body hyperthermia has been shown to have anti-tumor effects through an immune-modulating mechanism. Before it is widely applied in the clinic, tremendous mechanistic research in animals is necessary to adhere to evidence-based principles. The radio frequency electromagnetic field (RF-EMF) based heating facility could be a good choice for hyperthermia treatment, but the heating characteristics of a facility, including structure design, electromagnetic and thermal dosimetry, and the biologic effects of hyperthermia, need to be well elucidated. Here, we reported the heating characteristic study on a resonant chamber (RC) excited by a 1800 MHz solid source. The EMF in the RC was stirred by 24 static reflectors, which resulted in the standard deviation of electric field intensity being below 3 dB in the EM homogeneity evaluation. For the exposure scenario, six free-moving mice were loaded into separate cases and exposed simultaneously in the RC. The EMF energy absorption and distribution in exposed mice were calculated with the 12-plane-waves method of numerical simulation. Different levels of core body temperature increment in exposed mice were achieved through regulation of the source output power. Overexpression of heat shock proteins (HSPs) was detected in the liver, lung and muscle, but not in the brain of the exposed mice. The levels of representative inflammatory cytokines in the serum, TNF-α and IL-10 increased post RC exposure. Based on the heating characteristic study and validation, the applied RC would be a qualified heating system for mild whole-body hyperthermia effect research in mice.
Mild whole-body hyperthermia has potential anti-tumor effects by modulating the immune system. A radio frequency electromagnetic field (RF-EMF)-based heating facility emerges as a suitable option for hyperthermia treatment. However, a qualified heating facility for scientific research must elucidate its heating characteristics and validate the biological effects associated with hyperthermia. In this study, we report the characteristics of a rodent heating chamber using EMF energy. The special structure of the chamber not only achieved efficient EMF usage but also ensured the homogeneity in EMF spatial distribution, animal EM absorption, and EMF-caused biological effects. Our work may offer insights for designing a low-cost yet reliable heating facility for scientific research.

Through various studies on thermoelectric (TE) materials, thin film configuration gives superior advantages over conventional bulk TEs, including adaptability to curved and flexible substrates. Several different thin film deposition methods have been explored, yet magnetron sputtering is still favorable due to its high deposition efficiency and scalability. Therefore, this study aims to fabricate a bismuth telluride (Bi2Te3) and antimony telluride (Sb2Te3) thin film via the radio frequency (RF) magnetron sputtering method. The thin films were deposited on soda lime glass substrates at ambient temperature. The substrates were first washed using water and soap, ultrasonically cleaned with methanol, acetone, ethanol, and deionized water for 10 min, dried with nitrogen gas and hot plate, and finally treated under UV ozone for 10 min to remove residues before the coating process. A sputter target of Bi2Te3 and Sb2Te3 with Argon gas was used, and pre-sputtering was done to clean the target\'s surface. Then, a few clean substrates were loaded into the sputtering chamber, and the chamber was vacuumed until the pressure reached 2 x 10-5 Torr. The thin films were deposited for 60 min with Argon flow of 4 sccm and RF power at 75 W and 30 W for Bi2Te3 and Sb2Te3, respectively. This method resulted in highly uniform n-type Bi2Te3 and p-type Sb2Te3 thin films.

BACKGROUND: We aimed to assess evidence of long-term effects of exposure to radiofrequency (RF) electromagnetic fields (EMF) on indicators of cognition, including domains of learning and memory, executive function, complex attention, language, perceptual motor ability and social cognition, and of an exposure-response relationship between RF-EMF and cognition.
METHODS: We searched PubMed, Embase, PsycInfo and the EMF-Portal on September 30, 2022 without limiting by date or language of publication. We included cohort or case-control studies that evaluated the effects of RF exposure on cognitive function in one or more of the cognitive domains. Studies were rated for risk of bias using the OHAT tool and synthesised using fixed effects meta-analysis. We assessed the certainty of the evidence using the GRADE approach and considered modification by OHAT for assessing evidence of exposures.
RESULTS: We included 5 studies that reported analyses of data from 4 cohorts with 4639 participants consisting of 2808 adults and 1831 children across three countries (Australia, Singapore and Switzerland) conducted between 2006 and 2017. The main source of RF-EMF exposure was mobile (cell) phone use measured as calls per week or minutes per day. For mobile phone use in children, two studies (615 participants) that compared an increase in mobile phone use to a decrease or no change were included in meta-analyses. Learning and memory. There was little effect on accuracy (mean difference, MD -0.03; 95% CI -0.07 to 0.02) or response time (MD -0.01; 95% CI -0.04 to 0.02) on the one-back memory task; and accuracy (MD -0.02; 95%CI -0.04 to 0.00) or response time (MD -0.01; 95%CI -0.04 to 0.03) on the one card learning task (low certainty evidence for all outcomes). Executive function. There was little to no effect on the Stroop test for the time ratio ((B-A)/A) response (MD 0.02; 95% CI -0.01 to 0.04, very low certainty) or the time ratio ((D-C)/C) response (MD 0.00; 95% CI -0.06 to 0.05, very low certainty), with both tests measuring susceptibility to interference effects. Complex attention. There was little to no effect on detection task accuracy (MD 0.02; 95% CI -0.04 to 0.08), or response time (MD 0.02;95% CI 0.01 to 0.03), and little to no effect on identification task accuracy (MD 0.00; 95% CI -0.04 to 0.05) or response time (MD 0.00;95% CI -0.01 to 0.02) (low certainty evidence for all outcomes). No other cognitive domains were investigated in children. A single study among elderly people provided very low certainty evidence that more frequent mobile phone use may have little to no effect on the odds of a decline in global cognitive function (odds ratio, OR 0.81; 95% CI 0.42 to 1.58, 649 participants) or a decline in executive function (OR 1.07; 95% CI 0.37 to 3.05, 146 participants), and may lead to a small, probably unimportant, reduction in the odds of a decline in complex attention (OR 0.67;95%CI 0.27 to 1.68, 159 participants) and a decline in learning and memory (OR 0.75; 95% CI 0.29 to 1.99, 159 participants). An exposure-response relationship was not identified for any of the cognitive outcomes.
CONCLUSIONS: This systematic review and meta-analysis found only a few studies that provided very low to low certainty evidence of little to no association between RF-EMF exposure and learning and memory, executive function and complex attention. None of the studies among children reported on global cognitive function or other domains of cognition. Only one study reported a lack of an effect for all domains in elderly persons but this was of very low certainty evidence. Further studies are needed to address all types of populations, exposures and cognitive outcomes, particularly studies investigating environmental and occupational exposure in adults. Future studies also need to address uncertainties in the assessment of exposure and standardise testing of specific domains of cognitive function to enable synthesis across studies and increase the certainty of the evidence.
UNASSIGNED: This review was partially funded by the WHO radioprotection programme and prospectively registered on PROSPERO CRD42021257548.