Dielectric properties of human skin at an acupuncture point in the 50-75 GHz frequency range: a pilot study

Advances in Millimeter-Wave Treatment and Its Biological Effects Development

This comprehensive review critically examines the current state of research on the biological effects of millimeter-wave (MMW) therapy and its potential implications for disease treatment. By investigating both the thermal and non-thermal impacts of MMWs, we elucidate cellular-level alterations, including changes in ion channels and signaling pathways. Our analysis encompasses MMW's therapeutic prospects in oncology, such as inducing apoptosis, managing pain, and modulating immunity through cytokine regulation and immune cell activation. By employing a rigorous methodology involving an extensive database search and stringent inclusion criteria, we emphasize the need for standardized protocols to enhance the reliability of future research. Although MMWs exhibit promising therapeutic potential, our findings highlight the urgent need for further elucidation of non-thermal mechanisms and rigorous safety assessments, considering the intricate nature of MMW interactions and inconsistent study outcomes. This review underscores the importance of focused research on the biological mechanisms of MMWs and the identification of optimal frequencies to fully harness their therapeutic capabilities. However, we acknowledge the challenges of variable study quality and the necessity for advanced quality control measures to ensure the reproducibility and comparability of future investigations. In conclusion, while MMW therapy holds promise as a novel therapeutic modality, further research is imperative to unravel its complex biological effects, establish safety profiles, and optimize treatment protocols before widespread clinical application.

Evaluating Dielectric Properties for Assessing Water Content at Acupuncture Points: New Methodology

Importance

Understanding acupuncture point microenvironments is vital for optimizing treatment efficacy. Evaluating changes in water content at these points can provide further insights into the effects of acupuncture on tissues.

Objective

This study aimed to measure tissue dielectric constant (TDC) and assess changes in water content, specifically at stomach 36 (ST36, Zusanli) and spleen 6 (SP6, Sanyinjiao) acupuncture points.

Methods

In a controlled, blinded, randomized trial, 113 healthy volunteers were divided into six groups based on TDC sensor diameters (XS, M, and L): three control groups and three acupuncture groups. They were assessed at three time points: T1, baseline; T2, 20 min post-needle withdrawal; and T3, 40 min post-needle withdrawal. Electrical impedance (EI) was also analyzed. Significance level was set at p < 0.001.

Results

TDC at ST36 and SP6 significantly decreased with the XS probe at T2 and T3 compared with that at T1 (F8, 452: 54.61). TDC did not significantly vary between T2 and T3 with M and L probes. EI data indicated that the current passage increased in the SP (F2, 226: 39.32) and ST (F2, 226: 37.32) groups during T2 and T3 compared with that during T1 within their respective groups and controls.

Conclusions

and Relevance: This study demonstrated the efficacy of TDC measurements in detecting water content fluctuations at acupuncture points and their responses to needles. TDC measurements, which were validated against EI, provide valuable insights into acupuncture point microenvironments and thus help optimize treatments.

Physiological effects of millimeter-waves on skin and skin cells: an overview of the to-date published studies

The currently ongoing deployment if the fifth generation of the wireless communication technology, the 5G technology, has reignited the health debate around the new kind of radiation that will be used/emitted by the 5G devices and networks - the millimeter-waves. The new aspect of the 5G technology, that is of concern to some of the future users, is that both, antennas and devices will be continuously in a very close proximity of the users' bodies. Skin is the only organ of the human body, besides the eyes, that will be directly exposed to the mm-waves of the 5G technology. However, the whole scientific evidence on the possible effects of millimeter-waves on skin and skin cells, currently consists of only some 99 studies. This clearly indicates that the scientific evidence concerning the possible effects of millimeter-waves on humans is insufficient to devise science-based exposure limits and to develop science-based human health policies. The sufficient research has not been done and, therefore, precautionary measures should be considered for the deployment of the 5G, before the sufficient number of quality research studies will be executed and health risk, or lack of it, scientifically established.

5G Wireless Communication and Health Effects-A Pragmatic Review Based on Available Studies Regarding 6 to 100 GHz

The introduction of the fifth generation (5G) of wireless communication will increase the number of high-frequency-powered base stations and other devices. The question is if such higher frequencies (in this review, 6-100 GHz, millimeter waves, MMW) can have a health impact. This review analyzed 94 relevant publications performing in vivo or in vitro investigations. Each study was characterized for: study type (in vivo, in vitro), biological material (species, cell type, etc.), biological endpoint, exposure (frequency, exposure duration, power density), results, and certain quality criteria. Eighty percent of the in vivo studies showed responses to exposure, while 58% of the in vitro studies demonstrated effects. The responses affected all biological endpoints studied. There was no consistent relationship between power density, exposure duration, or frequency, and exposure effects. The available studies do not provide adequate and sufficient information for a meaningful safety assessment, or for the question about non-thermal effects. There is a need for research regarding local heat developments on small surfaces, e.g., skin or the eye, and on any environmental impact. Our quality analysis shows that for future studies to be useful for safety assessment, design and implementation need to be significantly improved.

Millimeter-wave emissivity as a metric for the non-contact diagnosis of human skin conditions

A half‐space electromagnetic model of human skin over the band 30–300 GHz was constructed and used to model radiometric emissivity. The model showed that the radiometric emissivity rose from 0.4 to 0.8 over this band, with emission being localized to a layer approximately one millimeter deep in the skin. Simulations of skin with differing water contents associated with psoriasis, eczema, malignancy, and thermal burn wounds indicated radiometry could be used as a non‐contact technique to detect and monitor these conditions. The skin emissivity of a sample of 30 healthy volunteers, measured using a 95 GHz radiometer, was found to range from 0.2 to 0.7, and the experimental measurement uncertainty was ±0.002. Men on average were found to have an emissivity 0.046 higher than those of women, a measurement consistent with men having thicker skin than women. The regions of outer wrist and dorsal forearm, where skin is thicker, had emissivities 0.06–0.08 higher than the inner wrist and volar forearms where skin is generally thinner. Recommendations are made to develop a more sophisticated model of the skin and to collect larger data sets to obtain a deeper understanding of the signatures of human skin in the millimeter wave band. Bioelectromagnetics. 38:559–569, 2017. © 2017 The Authors. Bioelectromagnetics published by Wiley Periodicals, Inc.

What is the Acupoint? A preliminary review of Acupoints

BACKGROUND

According to traditional Chinese medicine (TCM) theory, acupoints are specifically chosen sites of acupuncture manipulation, and also the basis for studying the mechanism of acupuncture. Stimulating different acupoints on the body surface could provide various therapeutic benefits. However, what is the acupoint? This question is not clear.

REVIEW SUMMARY

We focuse on examining the function of acupoints from different perspectives, including the local and the systemic effects of stimulating acupoints. For example, acupoints may release certain substances or incur some changes, which could adjust the function of organs, maintain homeostasis. Furthermore, the therapeutic effects of verum acupoints versus sham acupoints were discussed. However, due to insufficience in evidence and in current methodologies, research into mechanisms of acupuncture is still incomplete.

CONCLUSION

This review might explain, to some extent, what an acupoint is. Further research into the identity of acupoints is warranted, and multidisciplinary methods using novel technologies may yield significant advances over existing knowledge.

System for simultaneous measurements of bilaterally symmetrical acupoints multifrequency impedances

Devices which can obtain comparable bilaterally symmetrical acupoints (BSA) multifrequency impedances (MFI) are often needed in the detection of the energy balance states of acupoints in traditional Chinese medicine. To satisfy these needs, a two-channel impedance measurement system has been introduced which is capable of accurately and simultaneously measuring BSA MFI. The system includes a set of five electrodes, two of which are injected with exciting current signal to synchronously and equally excite BSA; the other three electrodes are used as sensors to simultaneously sense the response signal from both sides. The system also includes a PC-based time-domain signal testing platform with arbitrary current waveform generation and three channels (one exciting current and two response voltages) simultaneously sampling, and a set of MFI simultaneously unbiased computing algorithms based on special odd multisine current signal input. Preliminary validating experiments suggest that the system allows accurate and synchronous measurement of BSA MFI at least in the frequency range of 10 Hz to 60 kHz, and the obtained BSA MFI are well comparable.

Are physiological changes experienced by healthy subjects during acu-TENS associated with acupuncture point sensations?

BACKGROUND

Transcutaneous electrical nerve stimulation over acupuncture points (acu-TENS) has been reported to improve clinical outcomes. The objectives of the present study were to investigate whether acupuncture point sensations were experienced during acu-TENS, and whether such sensations were associated with any concomitant changes in autonomic nervous system activity.

METHODS

This study adopted a single-blinded, randomised, controlled trial methodology. A total of 36 healthy subjects were randomly assigned to an experimental group (acu-TENS on right LI4 and LI11 points); control group (acu-TENS to bilateral kneecaps); or placebo group (sham acu-TENS on right LI4 and LI11 points). Heart rate (HR), mean arterial blood pressure (MAP), SD of the NN interval (SDNN) and low frequency to high frequency ratio (LF/HF) were measured before, during and after intervention. The Hong Kong Chinese version of the Massachusetts General Hospital Acupuncture Sensation Scale (C-MMASS) index was used for quantifying the acupuncture point stimulation sensations.

RESULTS

The experimental group showed a significant increase in HR (mean (SD) 73.5 (6.3) to 75.9 (6.7) bpm, p=0.027), MAP (88.5 (4.5) to 91.0 (4.1) mm Hg, p=0.004), SDNN (143.36 (8.58) to 153.69 (7.64) ms, p=0.002) and LF/HF (1.26 (0.19) to 1.31 (0.21), p=0.037) during the intervention. The control group showed a significant increase in SDNN (140.21 (8.72) to 143.39 (9.47) ms, p=0.009) and LF/HF (1.21 (0.09) to 1.23 (0.12), p=0.033). There were no significant physiological changes in the placebo group. Overall C-MMASS indices for the experimental, control and placebo groups were 3.23 (0.3), 2.14 (0.6) and 0.29 (0.32), respectively. The between-group difference was statistically significant (F=139.24, df=2, p<0.05). However, correlation analysis did not support any association between sensation intensity and physiological responses in any groups (γ ranged from -0.36 to 0.25).

CONCLUSIONS

This study showed that 'acupuncture point sensations' were experienced during acu-TENS to LI4 and LI11, but such sensations were not associated with physiological responses induced during the stimulation.

Biophysical characteristics of meridians and acupoints: a systematic review

As an integral part of traditional Chinese medicine (TCM), acupuncture is a convenient and effective therapy with fewer adverse effects. Recently, researches on meridian essence have become core issues of modern TCM. Numerous experiments have demonstrated the objective existence of meridians by different technologies since 1950s, such as biophysics, biochemistry, and molecular biology. In this paper, we review biophysical studies on electric, acoustic, thermal, optical, magnetic, isotopic, and myoelectric aspects of meridians and acupoints. These studies suggest that meridians/acupoints have biophysical characteristics which are different from nonacupuncture points. Owing to the limitations of previous studies, future research using high-throughput technologies such as omics and multicenter randomized controlled trials should be performed to explore the acupuncture's mechanisms of action and demonstration of efficacy.