Low-frequency pulsed electromagnetic field pretreated bone marrow-derived mesenchymal stem cells promote the regeneration of crush-injured rat mental nerve

Bone marrow-derived mesenchymal stem cells （BMSCs） have been shown to promote the regeneration of injured peripheral nerves. Pulsed electromagnetic field （PEMF） reportedly promotes the proliferation and neuronal differentiation of BMSCs. Low-frequency PEMF can induce the neuronal differentiation of BMSCs in the absence of nerve growth factors. This study was designed to investigate the effects of low-frequency PEMF pretreatment on the proliferation and function of BMSCs and the effects of low-frequency PEMF pre-treated BMSCs on the regeneration of injured peripheral nerve using in vitro and in vivo experiments.In in vitro experiments, quantitative DNA analysis was performed to determine the proliferation of BMSCs, and reverse transcription-polymerase chain reaction was performed to detect S100 （Schwann cell marker）, glial fibrillary acidic protein （astrocyte marker）, and brain-derived neurotrophic factor and nerve growth factor （neurotrophic factors） mRNA expression. In the in vivo experiments, rat models of crush-injured mental nerve established using clamp method were randomly injected with low-frequency PEMF pretreated BMSCs, unpretreated BMSCs or PBS at the injury site （1 × 106 cells）. DiI-labeled BMSCs injected at the injury site were counted under the fluorescence microscope to determine cell survival. One or two weeks after cell injection, functional recovery of the injured nerve was assessed using the sensory test with von Frey filaments. Two weeks after cell injection, axonal regeneration was evaluated using histomorphometric analysis and retrograde labeling of trigeminal ganglion neurons. In vitro experiment results revealed that low-frequency PEMF pretreated BMSCs proliferated faster and had greater mRNA expression of growth factors than unpretreated BMSCs. In vivo experiment results revealed that compared with injection of unpretreated BMSCs, injection of low-frequency PEMF pretreated BMSCs led to higher myelinated axon count and axon density and more DiI-labeled neurons in the trigeminal ganglia, contributing to rapider functional recovery of injured mental nerve. These findings suggest that low-frequency PEMF pretreatment is a promising approach to enhance the efficacy of cell therapy for peripheral nerve injury repair.

The Effects of High-intensity Pulsed Electromagnetic Field on Proliferation and Differentiation of Neural Stem Cells of Neonatal Rats in vitro

The effects of high-intensity pulsed electromagnetic stimulation （HIPEMS） on proliferation and differentiation of neonatal rat neural stem cells in vitro were investigated. Neural stem cells derived from neonatal rats were exposed to 0.1 Hz, 0.5–10 Tesla （T） [8 groups of B–I, respectively], 5 stimuli of HIPEMF. The sham exposure controls were correspondingly established. Inverted phase contrast microscope was used to observe the cultured cells, MTT assay to detect the viability of the cells as expressed by absorbance （A） value, and flow cytometry to measure differentiation of neural stem cells. The results showed that A values of neural stem cells in both 3.0 T and 4.0 T groups were significantly higher than the other groups 24 to 168 h post HPEMS, indicating a strong promotion of the growth of neural stem cells （P〈0.05）. The A values of neural stem cells in the 6.0 T, 8.0 T, and 10.0 T groups were lower than the sham exposure control group, indicating a restraint of the growth of neural stem cells. The rate of neuron-specific enolase-positive neurons revealed by flow cytometry in HPEMS groups was the same as that in control group （P〉0.05）. It was suggested that 0.1 Hz, 5 pulses stimulation of HPEMS within certain scale of intensity （0.5–10.0 T）, significantly promoted the growth of neural stem cells with the rational intensity being 4.0 T.

Research on Strong Pulsed Electromagnetic Field Test Method by Time-frequency Combination

Many conventional methods of testing strong and pulsed electromagnetic fields,the ones used in radars for example,had deficiencies due to the difficulty in obtaining simultaneous information about the electromagnetic field's peak both in the time domain and in the frequency domain.With regard to this problem,after analyzing the time-domain and the frequency-domain characteristics of radar pulsed signals,we propose a new time-frequency combination test method based on the correction of the test parameters,as well as its correction method at different bandwidths.The test method is applied in a quick test of a high-power pulsed radar signal,and the corrected results have error less than 1 dB in both the time domain and the frequency domain,which indicates that the proposed time-frequency combined method is effective in testing strong and pulsed electromagnetic fields.

Role of pulsed electromagnetic fields after joint replacements

Although the rate of patients reporting satisfaction is generally high after joint replacement surgery, up to 23% after total hip replacement and 34% after total knee arthroplasty of treated subjects report discomfort or pain 1 year after surgery. Moreover, chronic or subacute inflammation is reported in some cases even a long time after surgery. Another open and debated issue in prosthetic surgery is implant survivorship, especially when related to good prosthesis bone ingrowth. Pulsed Electro Magnetic Fields(PEMFs) treatment, although initially recommended after total joint replacement to promote bone ingrowth and to reduce inflammation and pain, is not currently part of usual clinical practice. The purpose of this review was to analyze existing literature on PEMFs effects in joint replacement surgery and to report results of clinical studies and current indications. We selected all currently available prospective studies or RCT on the use of PEMFs in total joint replacement with the purpose of investigating effects of PEMFs on recovery, pain relief and patients’ satisfaction following hip, knee or shoulder arthroplasty. All the studies analyzed reported no adverse effects, and good patient compliance to the treatment. The available literature shows that early control of joint inflammation process in the first days after surgery through the use of PEMFs should be considered an effective completion of the surgical procedure to improve the patient’s functional recovery.

Promotional effects of exogenous stimulation with pulsed electromagnetic fields on skin wound healing in diabetic rats

Objective:The current study aims to identify the effects of exogenous application of pulsed electromagnetic fields on skin wound healing in diabetic rats, and thus provides experimental evidence for its more scientific clinical application in the future.Methods: The diabetic animal models were established via intraperitoneal injection of streptozotocin in 4-month-old male rats. Fourth eight rats were randomly assigned into the diabetes group (DM) and diabetes coupled with pulsed electromagnetic fields (DM+PEMF) group. Another 24 normal rats were used as the blank control group (Control). Then, all the rats in the three groups were subjected to dorsal surgery for the establishment of soft tissue wound model (circular wound with the diameter of 2 cm). Then, the rats in the DM+PEMF group were subjected to pulsed electromagnetic fields stimulation. Then, 6 rats in each group were sacrificed at Day 5, 12 and 19 post surgery. The glucose levels, wound closure, wound healing time and tissue tensile strength were examined and analyzed.Results: Pulsed electromagnetic fields significantly increased the wound closure rate in diabetic rats at Day 5, 12 and 19 post surgery, decreased overall wound healing period in diabetic rats, and also enhanced tissue tensile strength in diabetic rats at Day 5, 12 and 19 post surgery.Conclusion: Low-intensity pulsed electromagnetic fields can significantly accelerate diabetic wound healing process, and also improve diabetic tissue repair capacity. This study may be helpful for providing more scientific and reasonable experimental evidence for the treatment of pulsed electromagnetic fields on diabetic wound healing in clinics.

Pulsed electromagnetic field stimulation enhances neurite outgrowth in neural cells and modulates inflammation in macrophages

Nerve regeneration following traumas remains an unmet challenge.The application of pulsed electromagnetic field(PEMF)stimulation has gained traction for a minimally invasive regeneration of nerves.However,a sys-tematic exploration of different PEMF parameters influencing neuron function at a cellular level is not available.In this study,we exposed neuroblastoma F11 cells to PEMF to trigger beneficial effects on neurite outgrowth.Different carrier frequencies,pulse repetition frequencies,and duty cycles were screened with a custom ad hoc setup to find the most influential parameters values.A carrier frequency of 13.5 MHz,a pulse repetition frequency of 20 Hz,and a duty cycle of 10%allowed maximal neurite outgrowth,with unaltered viability with respect to non-stimulated controls.Furthermore,in a longer-term analysis,such optimal conditions were also able to in-crease the gene expression of neuronal expression markers NeuN and Tuj-1 and transcription factor Ngn1.Finally,the same optimal stimulation conditions were also applied to THP-1 macrophages,and both pro-inflammatory(TNF-α,IL-1β,IL-6,IL-8)and anti-inflammatory cytokines(IL-10,CD206)were analyzed.The optimal PEMF stimulation parameters did not induce differentiation towards an M1 macrophage phenotype,decreased IL-1β and IL-8 gene expression,decreased TNF-α and IL-8 cytokine release in M1-differentiated cells,increased IL-10 and CD206 gene expression,as well as IL-10 cytokine release in M0 cells.The specific PEMF stimulation regime,which is optimal in vitro,might have a high potential for a future in vivo translation targeting neural regeneration and anti-inflammatory action for treating peripheral nerve injuries.

The pulsed high magnetic field facility and scientific research at Wuhan National High Magnetic Field Center

Wuhan National High Magnetic Field Center(WHMFC)at Huazhong University of Science and Technology is one of the top-class research centers in the world,which can offer pulsed fields up to 90.6 T with different field waveforms for scientific research and has passed the final evaluation of the Chinese government in 2014.This paper will give a brief introduction of the facility and the development status of pulsed magnetic fields research at WHMFC.In addition,it will describe the application development of pulsed magnetic fields in both scientific and industrial research.

Inverse problem of pulsed eddy current field of ferromagnetic plates

To determine the wall thickness, conductivity and permeability of a ferromagnetic plate, an inverse problem is established with measured values and calculated values of time-domain induced voltage in pulsed eddy current testing on the plate. From time-domain analytical expressions of the partial derivatives of induced voltage with respect to parameters,it is deduced that the partial derivatives are approximately linearly dependent. Then the constraints of these parameters are obtained by solving a partial linear differential equation. It is indicated that only the product of conductivity and wall thickness, and the product of relative permeability and wall thickness can be determined accurately through the inverse problem with time-domain induced voltage. In the practical testing, supposing the conductivity of the ferromagnetic plate under test is a fixed value, and then the relative variation of wall thickness between two testing points can be calculated via the ratio of the corresponding inversion results of the product of conductivity and wall thickness. Finally, this method for wall thickness measurement is verified by the experiment results of a carbon steel plate.

Cytogenetic Effects of Pulsing Electromagnetic Field on Domestic Pig Lymphocytes in Vitro

The effects of pulsing electromagnetic fields(PEMFs)on cells are very important subjects in the field of bioelectromagnetics.In this experiment,the cytogenetic effects of PEMF on domestic pig lymphocytes were tested in vitro.Pig lymphocytes in RPMI 1640 medium were exposed to PEMFs of 100 kHz and 200 kHz for 12,24 and 48 hours.Chromosomal aberrations(aneuploidy,breaks,gaps,et al)were significantly increased in exposed cultures,and of these aberrations,56%chromosomal or chromatid breaks and 42%gaps induced by PEMFs were the points of pig chromosomal fragile sites.The baseline frequency of sister chromatid exchange(SCE)increased after exposing lymphocytes continuously to PEMFs of 100 kHz and 200 kHz for 48 hours.These results suggested that the exposure to PEMFs might induce a type of DNA lesion and chromosomal aberrations.

Effect of pulsed electromagnetic frequency on the microstructure, wear and solid erosion resistance of CrAlN coatings deposited by arc ion plating

In this work,the chromium aluminum nitride(CrAlN)coatings were prepared on TC11 titanium alloy by composite magnetic field cathodic arc ion plating with controllable pulse electromagnetic combined with permanent magnet.The effects of electromagnetic frequency on the morphology,microstructure,nano-hardness and elastic modulus of the coatings were investigated by scanning electron microscope(SEM),X-ray diffraction(XRD)and nano-indenter.This paper has mainly studied the influence of CrAlN coatings which are prepared at various electromagnetic frequencies on the wear and erosion resistance through a series of wear and solid particle erosion experiments.It was found that the deposition rate of CrAlN coatings increases with the increase of electromagnetic frequency.And CrAlN coatings all preferentially grew along the(111)crystal plane.At 16.7 Hz,with the increase of pulsed electromagnetic frequency,the hardness is the highest(23.6 GPa)and the adhesion is the highest(41.5 N).In addition,the coating deposition exhibited the best wear and solid erosion resistance at 16.7 Hz and 33.3 Hz,the friction coefficient is about 0.35,and the erosion rate is about 0.2μm/g at 30°and less than 1μm/g at 90°,respectively.These results indicate that the CrAlN coating formed at an appropriate pulsed electromagnetic frequency can achieve excellent mechanical properties,wear and solid erosion resistance.

Clinical efficacy of electromagnetic field therapy combined with traditional Chinese pain-reducing paste in myofascial pain syndrome

BACKGROUND Pulsed electromagnetic field(PEMF)therapy is widely used to treat myofascial pain syndrome(MPS).Damp-clearing and pain-reducing paste(DPP)comprises medical herbs and has been a traditional method of reducing myofascial pain in China for a long time,and it is usually administered with heating.However,the synergistic effect of PEMF therapy on heating-DPP in patients with MPS is unclear.AIM To investigate the synergistic effect of PEMF therapy plus heating-DPP in lumbar MPS.METHODS This double-blind,randomized,placebo-controlled trial was conducted on 120 patients with lumbar MPS who were randomly divided into an experimental group(EG,n=60)and a control group(CG,n=60).Patients in both groups were treated with heating-DPP combined with PEMF therapy;however,the electromagnetic function of the therapeutic apparatus used in the CG was disabled.Each treatment lasted for 20 min and was applied five times a week for two weeks.The short-form McGill Pain Questionnaire was applied at five time points:pretest,end of the first and second weeks of treatment,and end of the first and fourth week after completing treatment.Visual analog scale(VAS),present pain intensity index(PPI),and pain rating index(PRI;total,affective pain,and sensory pain scores)scores were then analyzed.RESULTS Compared with the CG,the VAS,PPI and PRI scores(total,affective pain and sensory pain scores)in the EG were significantly lower after treatment and during follow-up.CONCLUSION PEMF therapy combined with heating-DPP showed better efficacy than heating-DPP alone in reducing the overall intensity of pain and sensory and affective pain.

A Pulsed Electromagnet for Laser Wakefield Electron Acceleration Experiments

Laser Wakefield plasma acceleration of electrons to energies above 10 GeV, may be possible in the new high power Laser beam facilities. The design of an Electron Spectrometer with an electro-magnet with adjustable magnetic field is proposed for the characterization of electron energy spectrum with a precision better than 10% for the entire energy range from 0.5 GeV to 38 GeV. The expected precision in the measurement of the electron energy is calculated as a function of the magnetic field, of the electron energy and of the magnet length. To outline the advantages offered by a pulsed electromagnet with high magnetic fields, the mass and the electric power lost in the coils of a 4 m long electromagnet with continuous current and Iron yoke are calculated.

电磁脉冲电场测量技术研究综述

宽频带大动态范围的脉冲电场测量是电磁脉冲效应、防护以及电磁兼容等相关领域的一项共性基础技术,在过去50年以来受到研究人员的广泛关注,并发展出不同手段的测量技术。无源微分(D-dot)测量传感器带宽相对较高,但尺寸较大、集成度低;有源光纤测量系统最大测量带宽约为1 GHz,尺寸相对较小、集成度高、实用性强。集成光学传感器作为一种带宽宽、体积小的无源传感器,各国均有研究。本文主要回顾上述几种脉冲电场测量技术近期研究进展,并结合发展现状分析脉冲电场测量技术存在的挑战和未来可能的研究方向,为相关领域研究人员提供参考。

脉冲磁场幅值对制备聚硅氧烷复合材料的电磁屏蔽性能影响规律

脉冲磁场已被证实通过诱导纳米粒子在基体中取向排列可以显著提高复合材料的电磁屏蔽性能,然而脉冲磁场幅值对复合材料电磁屏蔽性能的影响规律尚不明确。因此,采用脉宽为10μs、频率为50Hz的脉冲磁场诱导片状羰基铁(flaky carbonyl iron,FCI)在聚二甲基硅氧烷(polydimethylsiloxane,PDMS)中定向排列,研究磁场幅值(0~0.7T)对复合材料电磁屏蔽性能的影响规律。用扫描电子显微镜(scanning electron microscope,SEM)和X射线衍射(X-ray diffraction,XRD)对纳米粒子的取向和排列进行了表征。结果表明,脉冲磁场可以有效控制羰基铁的取向和排列,形成导电网络结构,提高复合材料的导电性,最终显著提高取向复合材料的电磁屏蔽性能。脉冲磁场对复合材料的屏蔽效能增强效果可达27%,达到的最高屏蔽效率为15.36dB。理论分析和实验结果的一致性证实了微秒级脉冲磁场在改善复合材料电磁屏蔽性能方面的有效性。该研究制备的高性能柔性电磁屏蔽复合材料具有应用于先进电子设备的潜力。

基于多场耦合求解的大规格镁合金扁锭差相脉冲电磁半连续铸造

本文以大规格镁合金扁锭半连续铸造为研究对象,采用基于多场耦合的数值模拟技术模拟了差相脉冲磁场作用下镁合金扁锭半连续铸造过程中的宏观物理场,研究了差相脉冲磁场相位差对电磁力、温度场、凝固过程、溶质元素分布及宏观偏析的影响。结果表明:相位差对凝固中后期影响更明显。当相位差从0°增至72°时,凝固初期换热有所减弱;而凝固中后期换热增强,液穴深度明显变浅,中心部位凝固速度加快,横截面内温度场变均匀。此外,适当提高相位差至72°有利于缓解两相区内贫溶质的问题,减少凝固后横截面内最大负偏析率和整体偏析率;相位差继续增大到108°不仅明显削弱了凝固前期的换热强度,而且还会削弱凝固中后期的换热强度,使液穴变深,凝固速度减慢,偏析率增大。

昼夜节律对PEMFs暴露小鼠血液流变学及红细胞脆性的影响

目的: 探讨昼夜节律对脉冲电磁场暴露小鼠血液流变学的影响.方法: 将30只雄性小鼠随机分为3组(n=10): 对照组、磁场A组和磁场B组.两磁场组饲养于强度为8×10-4 T的脉冲电磁场(pulsed electromagnetic fields,PEMFs)环境中(f=15 Hz),暴磁时间均为6 h/d(磁场A组为白天10∶00～16∶00,磁场B组为夜间22∶00～4∶00).对照组饲养于线圈中,但不暴磁.10 d后统一摘右眼取血,对血液流变学指标及红细胞脆性进行测定.结果: 磁场组与对照组比较,血液流变学特性以及红细胞脆性的差异均有统计学意义(P<0.05);两磁场组(A,B)之间比较,血液流变学各指标和开始溶血NaCl溶液浓度的差异具有显著性意义(P<0.05),而完全溶血的浓度差异不明显(P>0.05).结论: PEMFs可以改善小鼠血液流变特性,降低红细胞脆性,白天暴磁效果优于夜间,提示昼夜节律对其生物效应有影响.

脉冲电磁场在骨科相关疾病中的应用

背景:脉冲电磁场是一种无创、无辐射的治疗方法,临床利用脉冲电磁场治疗骨科疾病已经取得了一定的疗效。目的:综述脉冲电磁场参与治疗骨科疾病的临床应用现状,为骨科疾病的临床治疗提供科学的理论依据。方法:由第一作者运用计算机检索PubMed、中国生物医学文献服务系统(CBM)、Cochrane Library、中国期刊全文数据库(CNKI)以及万方数据资源系统中脉冲电磁场治疗骨科疾病的相关研究,以“脉冲电磁场,骨科,骨关节炎,骨质疏松,骨愈合,电磁导航”为中文检索词,以“pulsed electromagnetic field,orthopedics,osteoarthritis,osteoporosis,bone healing,electromagnetic navigation”为英文检索词,同内容相关文献则选择近期发表文献,从检索结果中选择了69篇文献进行综述。结果与结论:脉冲电磁场对骨折愈合疗效确切,通过抑菌、杀菌、抗炎及促进骨愈合等途径治疗骨髓炎,可抑制骨质疏松及其进展,又通过多种途径治疗早期骨关节炎、股骨头坏死及晚期关节置换术后康复。但脉冲电磁场治疗多种骨科疾病的机制仍不明确,多数研究仍处于初级阶段,今后依然需要从高质量的研究和临床试验中获得更可靠的证据,为骨科疾病的临床治疗提供更完善的依据。

脉冲电磁场联合双膦酸盐对绝经后骨质疏松症患者心理健康和生活质量的影响

目的:观察脉冲电磁场联合双膦酸盐对绝经后骨质疏松症患者心理健康和生活质量的影响。方法:选取2022年10月—2023年5月南昌市洪都中医院收治的90例绝经后骨质疏松症患者为研究对象,采用随机单盲、平行对照的研究方法。将患者随机分为三组,各30例。A组给予低频脉冲电磁场联合伊班膦酸钠治疗,B组采用低频脉冲电磁场治疗,C组采用伊班膦酸钠治疗,三组均连续治疗3个月。比较三组性激素、骨密度、骨代谢指标、心理状态、疼痛程度、生活质量及不良反应发生情况。结果:治疗后三组髋部及腰椎骨密度均提高,且A组高于B组、C组(P<0.05);治疗后三组β-胶原降解产物(β-CTX)、总Ⅰ型前胶原氨基端肽(T-PⅠNP)均降低,A组低于B组、C组,骨钙素(OCN)、25-羟维生素D均升高,A组高于B组、C组(P<0.05);治疗后三组焦虑自评量表(SAS)、抑郁自评量表(SDS)、视觉模拟评分法(VAS)评分均降低,A组低于B组、C组(P<0.05);治疗后,三组健康调查量表36(SF-36)各维度评分均提高,且A组高于B组、C组(P<0.05);三组治疗期间均未见严重不良反应。结论:脉冲电磁场联合双膦酸盐治疗可调节绝经后骨质疏松症患者骨代谢指标,提高骨密度,缓解骨痛,改善心理状况,提升生活质量,且治疗安全性较高。

组合式电磁成形技术研究进展

电磁成形技术是一种典型的高速率电磁脉冲成形技术,可显著地提高材料的延展性,减小工件回弹和起皱,降低设备制造成本。在电磁成形技术发展过程中,电磁成形力场的有效加载和调控颇具挑战,早期的电磁成形方案基本实现工件排斥力成形效果,其电磁力分析中主要以排斥力占据主导,应用有较大的局限性,如今优势明显的组合式电磁成形技术开始进入大众视野。该文在简述电磁成形基本原理及电磁力调控方式的基础上,根据组合式方法应用的不同层面,将近年来涌现的研究成果划分为:驱动线圈组合式、电磁力组合式及工艺组合式三类电磁成形技术,针对每一类技术,分别阐述了其实施原理、技术方案及应用成效,并进一步归纳了不同技术的适用范围及研究重点。最后,在这些研究成果的基础上,对组合式电磁成形技术未来的发展方向进行了展望。

脉冲电磁场可抑制老年大鼠膝关节软骨退变

背景:脉冲电磁场作为一种重要的物理治疗方法对骨关节炎的疗效确切,但其作用机制尚未完全明确。目的:观察脉冲电磁场对老年大鼠膝关节软骨退变的影响。方法:选取8只6月龄SD大鼠作为青年组,正常饲养8周,不做任何处理;将16只22月龄SD大鼠随机分为老年组(n=8)和脉冲电磁场组(n=8),对脉冲电磁场组大鼠进行脉冲电磁场干预,1次/d,每周5 d,连续干预8周,老年组正常饲养8周,不做任何处理。8周后麻醉处死所有大鼠,进行相关指标的检测。结果与结论:①与青年组相比,老年组大鼠血清Ⅱ型胶原C端肽水平升高(P<0.05);与老年组相比,脉冲电磁场组大鼠血清Ⅱ型胶原C端肽水平降低(P<0.05);②显微CT显示,与青年组相比,老年组大鼠胫骨的骨体积分数、骨密度、骨小梁数量均降低(P<0.05),骨小梁间隙增大(P<0.05);与老年组相比,脉冲电磁场组大鼠胫骨的骨体积分数、骨密度、骨小梁数量均升高(P<0.05),骨小梁间隙减少(P<0.05);③胫骨平台番红O-固绿染色显示,老年组大鼠关节软骨结构紊乱,软骨细胞明显减少,无法区分潮线;脉冲电磁场组上述情况有所改善;④RT-qPCR与Western blot检测显示,与青年组相比,老年组大鼠关节软骨及软骨下骨中基质金属蛋白酶1、基质金属蛋白酶13、P53、P21的mRNA与蛋白表达均升高(P<0.05);与老年组相比,脉冲电磁场组大鼠关节软骨及软骨下骨中基质金属蛋白酶1、基质金属蛋白酶13、P53、P21的mRNA与蛋白表达均降低(P<0.05);⑤结果表明,脉冲电磁场可能通过抑制P53/P21的表达抑制软骨细胞衰老,缓解关节软骨降解及抑制软骨下骨骨质疏松,改善老年大鼠骨关节炎。