Search Results (1,412)

Surface Acoustic Wave (SAW) technology, long central to analog signal processing and RF filtering, is undergoing a major renewal. Driven by advances that decouple SAWs from traditional piezoelectric materials and fixed-function devices, the field is gaining unprecedented control over acoustic, optical, and electronic interactions at the micro and nanoscale. This review synthesizes these developments across four fronts: new physical mechanisms for SAW manipulation, emerging material platforms, ranging from thin films to 2D systems, along with reconfigurable device architectures and circuits, and the expanding landscape of applications they enable. Optical methods are reshaping how SAWs are generated and controlled, bypassing the limits of conventional electromechanical coupling. Coherent optical excitation of high-Q SAW cavities via Brillouin-like optomechanical interactions now grants access to modes in non-piezoelectric substrates such as diamond and silicon, while on-chip SAW excitation in photonic waveguides through backward stimulated Brillouin scattering opens new integrated sensing routes. In parallel, magneto-acoustic experiments have revealed nonreciprocal SAW diffraction from resonant scattering in magnetoelastic gratings. On the device side, ZnO thin-film transistors integrated on LiNbO₃ exploit acoustoelectric coupling to realize voltage-tunable phase shifters; UHF Z-shaped delay lines achieve high sensitivity in a compact footprint; and parametric synthesis of wideband, multi-stage lattice filters targets 5G-class performance. Atomistic simulations show that SAW propagation in 2D MXene films can be engineered via surface terminations, while aerosol jet printing and SAW-assisted particle patterning provide agile, cleanroom-light fabrication of microfluidic and magnetic components. These advances enable applications ranging from hybrid quantum systems and quantum links to lab-on-a-chip particle control, SBS-based and UHF sensing, reconfigurable RF front-ends, and soft robotic actuators based on patterned magnetic composites. At the same time, optical techniques offer non-contact probes of dissipation, and MXenes and other emerging materials open new regimes of acoustic control. Conclusively, they are transforming SAW technology into a versatile, programmable platform for mediating complex interactions in next-generation electronic, photonic, and quantum systems. Full article

Background/Objectives: Stroke is a sudden neurological event caused by disrupted cerebral blood flow and represents a leading cause of acquired disability worldwide. Motor impairments and spasticity are among the most prevalent sequelae, significantly limiting functional independence and quality of life. Non-invasive electrotherapy has emerged as a complementary strategy in neurorehabilitation aimed at enhancing neuroplasticity and improving motor recovery. To systematically review current evidence regarding the effectiveness of non-invasive electrotherapy modalities in the rehabilitation of motor sequelae and spasticity following stroke, and to examine their theoretical and clinical rationale. Methods: A systematic literature review was conducted in accordance with PRISMA 2020 guidelines. The protocol was prospectively registered in the Open Science Framework (OSF). A comprehensive search was performed in Pubmed, Web of Science (WoS), and Scopus for studies published up to 14 November 2023, using the terms “Electric Stimulation Therapy” and “Stroke”. The methodological quality was assessed using the PEDro scale. The levels of evidence were classified according to the Oxford Centre for Evidence-Based Medicine criteria, and the risk of bias was evaluated using the Cochrane Risk of Bias tool (RoB 2). Results: Sixteen studies were included in the review. The analyzed interventions comprised neuromuscular electrical stimulation (NMES), transcutaneous electrical nerve stimulation (TENS), functional electrical stimulation (FES), neuromuscular electrical stimulation combined with transcranial magnetic stimulation (NMES + rTMS), transcranial direct current stimulation (tDCS), and afferent electrical stimulation (AES). Overall, the methodological quality of the included studies ranged from moderate to high, with PEDro scores between 6 and 9 out of 10. According to the Oxford Centre for Evidence-Based Medicine classification, most studies corresponded to level 1b evidence, while a smaller proportion were classified as level 2b. A risk of bias assessment using the Cochrane RoB 2 tool showed that the majority of the included studies presented a low risk of bias across most domains, although some concerns were identified in the domains of randomization and measurement in a limited number of trials. Across modalities, consistency within group improvement in motor function and spasticity was reported. However, between group comparisons with conventional rehabilitation were often inconsistent and did not consistently demonstrate superiority. The variability in stimulation parameters, intervention duration, and outcome measures further limited direct comparisons across studies. Conclusions: Non-invasive electrotherapy appears to be a safe and promising adjunct to conventional stroke rehabilitation. Nevertheless, further high-quality studies are required to clarify the underlying neurophysiological mechanisms and to establish standardized treatment protocols. Full article

Background: Migraine is a chronic neurological disorder with a high prevalence of psychiatric comorbidity, including anxiety and depression, which compound functional impairment and reduce health-related quality of life (HRQoL). Repetitive transcranial magnetic stimulation (rTMS) is a non-pharmacological neuromodulatory intervention targeting both pain and affective circuits; however, predictors of HRQoL improvement following rTMS remain poorly characterized. Methods: In this exploratory observational study, 32 adults with migraines underwent 10–40 rTMS sessions. Quality of life was assessed using the WHOQOL-BREF and Migraine-Specific Quality of Life Questionnaire (Migraine-QoL). Psychiatric burden, headache impact, and disability were evaluated using HAMA, HAMD, HIT-6, and MIDAS at baseline and post-intervention. Paired t-tests, Spearman correlations, and linear regression identified predictors of QoL change. Results: Both WHOQOL-BREF and Migraine-QoL improved significantly following rTMS (p < 0.001). Antipsychotic use was associated with greater overall QoL improvement (p = 0.026). Given the very small subgroup size (n = 7), this finding should be interpreted with extreme caution and considered hypothesis-generating only. Higher baseline HIT-6 and HAMA correlated with greater Migraine-QoL gains (p = 0.001 and p = 0.013). In multivariate regression, higher headache severity independently predicted Migraine-QoL improvement (R² = 0.514, p < 0.001). Conclusions: rTMS produced clinically meaningful QoL improvements in migraine. Headache burden emerged as an independent predictor, while associations with anxiety severity and antipsychotic use should be considered exploratory. Full article

The effects of static magnetic fields (SMFs) on fibroblast proliferation and migration remain debated, largely due to variability in field intensity, orientation, and exposure duration, as well as the predominant use of endpoint-based assays that may not fully capture the temporal dynamics of cellular responses. Thus, it remains unclear whether reported SMF effects reflect changes in proliferation, migration, or both. Here, we examined how SMFs with different field configurations affect NIH3T3 fibroblast behavior. Three setups were tested: a field generated by two neodymium magnets arranged in a face-to-face configuration on opposite sides of the culture dish (SMF1) and single-magnet setups with either the north (SMF2 and SMF2a) or south poles (SMF3 and SMF3a) facing the cells. SMF1 was associated with a 41% increase in proliferation relative to control, while single-cell migration velocities, directional persistence, and collective wound closure showed no detectable changes. In contrast, SMF2 and SMF3, as well as their low-field variants SMF2a and SMF3a, did not produce significant effects. Our results suggest that a specific SMF configuration is associated with increased fibroblast proliferation without detectable changes in migration parameters under the tested conditions. This integrative approach helps contextualize prior divergent findings by suggesting that SMF effects may be configuration-dependent, thereby contributing to a more rational application of magnetic stimulation in cellular and tissue engineering contexts. Full article

Soluble growth stimulation protein form of interleukin-1 receptor-like 1 (ST2) may signal myocardial stress, and elevated ST2 blood levels are associated with adverse outcomes in adult heart disease. Data on ST2 in children with congenital heart disease (CHD) is limited. This study explored ST2 in newborns and older children with atrial septal defect (ASD), as this represents a common CHD type that remains clinically challenging to recognize in childhood with slowly evolving symptoms. A case–control study was carried out in newborn ASD cases versus controls measuring ST2 on dried blood spot samples and additionally in pediatric ASD cases versus controls on venous blood together with cardiac magnetic resonance before and after treatment. ST2 was higher in newborns with ASD (n = 19) compared to controls (n = 93); (p < 0.01). Receiver operating characteristics to diagnose newborn ASD by ST2 showed an area under the curve of 0.848. Levels of ST2 decreased in pediatric ASD (n = 16) after treatment (p = 0.014). Lower left ventricular ejection fraction correlated with higher ST2 levels before (r = −0.348) and after treatment (r = −0.497). Elevated ST2 in newborns may aid early ASD diagnosis. Levels of ST2 in pediatric ASD decrease after treatment, and higher levels are associated with lower left ventricular ejection fraction, warranting further study. Full article

Repairing maxillofacial bone defects remains a major clinical challenge due to inadequate vascularisation and poor integration with host tissue. While bioactive scaffolds have shown promise in supporting osteogenesis and angiogenesis, achieving robust and synchronised dual regenerative outcomes is still elusive. This study presents a multifunctional, cell-free magnetic hydrogel platform designed to biomimetically coordinate osteogenic and angiogenic processes for effective maxillofacial bone regeneration. The composite poly(vinyl alcohol)-vaterite (PVA-Vat) hydrogel scaffold incorporates tuneable magnetic nanoparticles (MNPs) composed of single-domain superparamagnetic iron oxide (Fe₃O₄). By harnessing magneto-mechanical cues to orchestrate bilateral communication between human bone mesenchymal stem cells and endothelial cells, this platform provides a deeper mechanistic understanding of coupled tissue regeneration and delivers superior dual-regenerative performance for maxillofacial bone repair. Under magnetic stimulation, a coculture system demonstrated strong osteogenesis-angiogenesis coupling mediated by reciprocal VEGFA-BMP2 signalling. This reciprocal crosstalk was evidenced by a synergistic amplification of VEGFA and BMP2 expression in coculture compared to monocultures, where MNP-stimulated osteoprogenitors secreted VEGFA to drive endothelial capillary-like network formation, while endothelial cells reciprocally enhanced endogenous BMP2 levels to accelerate osteoblastic mineralisation. These findings establish MNP-integrated hydrogels as a cell-free, multifunctional platform capable of synchronising dual regenerative pathways, offering a biomimetic strategy to overcome vascularisation and integration barriers in maxillofacial bone repair. Full article

The biological effects of weak low-frequency magnetic fields (LFMFs) remain controversial, particularly regarding frequency-specific resonance-like responses. Many previous studies tested different frequencies sequentially, potentially introducing uncontrolled environmental variability. This study aimed to evaluate frequency-dependent effects of LFMFs on the growth of juvenile Daphnia magna under strictly synchronized and temperature-controlled conditions. Genetically identical neonates from a single parthenogenetic brood were simultaneously exposed to sinusoidal 50 μT magnetic fields at 20, 25, 30, 35, or 40 Hz using spatially separated Helmholtz coils integrated into a closed-loop thermal stabilization system. Body length was measured after 48, 96, and 144 h of exposure. No significant growth differences were detected after 48 h. After 96 h, a significant biological effect was observed only at 30 Hz. The most pronounced responses occurred after 144 h, with significant growth stimulation at 25, 30, and 35 Hz and a maximal effect at 30 Hz. The frequency–response relationship exhibited a dome-shaped pattern that became less sharply peaked with prolonged exposure. These findings demonstrate duration-dependent and frequency-specific stimulation of juvenile daphnid growth with weak LFMFs. It suggests that exposure time critically influences the manifestation and breadth of resonance-like magnetobiological effects. Full article

Despite the high prevalence of low back pain (LBP), evidence supporting the clinical effects of repetitive peripheral magnetic stimulation (rPMS) remains limited. A combined double-coil and handheld rPMS approach may enhance the therapeutic potential of this technology. This observational case series analyzed prospectively collected routine clinical data from 37 patients treated with a combined protocol of static double-coil lumbar rPMS and dynamic handheld lower-limb rPMS. Pain intensity, disability, and quality of life were assessed at baseline, post-treatment, and 1-month follow-up. Statistical analyses were complemented by an evaluation of clinical relevance using established minimal clinically important difference (MCID) thresholds. Significant improvements were observed across all outcomes. Pain decreased by 62.5% post-treatment and by 87.5% at follow-up, while disability was reduced by 86.8% and 92.1%, respectively. Quality of life scores approximately doubled. High MCID responder rates and consistent within-group changes were observed; however, given the single-arm design without a control group, these findings should be interpreted as exploratory and hypothesis-generating rather than confirmatory evidence of treatment effectiveness. This combined rPMS approach was feasible and well tolerated in routine clinical practice and was associated with clinically meaningful within-group improvements in pain, function, and quality of life. Further controlled studies are warranted. Full article

Background/Objectives: Tobacco use is a leading cause of preventable death worldwide and is linked to major health and economic burden. Many smokers attempt to quit, yet long-term success rates with current medicines and counseling are still modest. Long-term nicotine exposure distorts brain systems involved in reward, craving, and self-control. These changes weaken inhibitory control and strengthen responses to smoking cues, which increases the risk of relapse. Transcranial magnetic stimulation (TMS) is a non-invasive technique that delivers magnetic pulses to specific cortical regions, most commonly the dorsolateral prefrontal cortex, to influence neural activity. This narrative review explored how transcranial magnetic stimulation may aid smoking cessation by acting on neural circuits linked to nicotine dependence. Methods: Five major databases were searched for studies published between 2015 and 2026. After removal of duplicates and screening, a total of 34 studies were included in this narrative synthesis. Randomized controlled trials, clinical studies, and neuroimaging investigations involving adults with nicotine dependence were included. A thematic narrative method was employed to synthesize findings due to the differences in study designs, protocols, and outcome measures. Results: TMS has been shown to attenuate cravings, decrease daily cigarette consumption, and decrease nicotine dependence in various studies. Several trials reported higher abstinence rates with active stimulation compared with sham treatment. Meta-analytic findings indicate stronger effects with 10 Hz stimulation and treatment courses of 20 sessions or more. Neuroimaging studies report changes in functional connectivity within reward, executive control, and salience networks, suggesting partial restoration of disrupted circuits. Treatment response varies according to age, educational level, baseline dependence, and stimulation parameters. Conclusions: These findings support transcranial magnetic stimulation as a promising brain-based approach for smoking cessation, while further well-designed trials with longer follow-up are still needed. Full article

Low-frequency pulsed magnetic fields (LFPMFs) are a recently developed modality for managing pain and promoting wound healing. The term LFPMF is used to describe low-intensity fields in wound and tissue studies, and is referred to as magnetic peripheral nerve stimulation (mPNS) in pain-related studies. The recent clearance of the first mPNS device for treating pain due to diabetic neuropathy by the FDA marks a watershed event in the clinical acceptance of these modalities. In addition to being within the frequency range of 0.5–100 Hz, the use of electromagnetic fields rather than electrical current, which dissipates in tissues, results in several therapeutic advantages of magnetic fields. These fields permeate tissues and affect a larger area. Full article

Selectively modulating specific brain-rhythm bands with physical stimuli helps both to reveal neural mechanisms and to provide non-pharmacological treatment avenues for brain disorders. This study proposes and implements a multi-channel transcranial magneto-acoustic stimulation driving system based on amplitude-modulated (AM) sine waves (AM-TMAS) intended to supply a reliable hardware platform for noninvasive, focal low-frequency rhythmic electrical stimulation of deep-brain structures. The driving system implements a 64-channel AM module based on an FPGA plus high-speed DACs. Multi-channel precision is achieved via a unified high-speed clock and a global UPDATE trigger. To overcome the large separation between envelope and carrier frequencies, we developed a high-fidelity AM waveform generation method based on DDS + LUT + envelope multiplication. The algorithm first centers the carrier samples to preserve waveform symmetry, then applies LUT-based envelope coefficients and fixed-point envelope multiplication, enabling high-precision AM outputs with carrier frequencies from 100 kHz to 2 MHz and envelope frequencies from 0.1 Hz to 100 kHz. We tested the system’s rhythmic multi-channel AM output performance across frequencies and also measured magneto-acoustic-coupled rhythmic electrical signals produced by the AM-TMAS driving setup. Any single channel reliably produced high-fidelity AM waveforms with a 500 kHz carrier and 8 Hz/40 Hz envelopes; the measured carrier was 499.998 kHz with excellent frequency stability. Both envelope and carrier frequencies are flexibly tunable. At the nominal 500 kHz carrier, envelope fidelity was further quantified: the extracted envelopes achieved NRMSEs of 1.0795% (8 Hz) and 1.9212% (40 Hz), confirming high-fidelity AM synthesis. Under a 0.3 T static magnetic field, the AM-TMAS driving system generated rhythmic electrical responses in physiological saline that carried the expected 40 Hz envelope. The proposed AM-TMAS driver achieves high accuracy in AM waveform generation and robust multi-channel performance, and—when combined with an external static magnetic field—can produce rhythmically modulated magneto-acoustic electrical stimulation. This platform provides a practical technical tool for brain-function research and the development of rhythm-targeted neuromodulation therapies. Full article

Background: Navigated repetitive TMS (nrTMS) is widely used for non-invasive mapping of cortical functions. Methodological improvement might be achieved by optimizing coil positioning based on electric-field modeling and augmented reality (AR)-guided neuronavigation to enhance spatial targeting accuracy and stimulation-induced language errors. Therefore, we compared electric-field-optimized, AR-guided nrTMS with conventional nrTMS using manually planned coil positioning. Methods: Twenty-eight healthy subjects underwent two MRI-guided left hemispheric nrTMS language mapping sessions. Each session used 10 Hz stimulation at a 100% resting motor threshold applied for 1.5 s per region of interest (ROI) during a synchronized object naming task. ROIs were defined according to the Corina cortical parcellation system. Manually defined and electric-field-optimized coil placements obtained using SimNIBS (v4.1.0) were applied; the optimized session was assisted by AR goggles. The primary outcome was the quantitative and categorical differences in cortical regions mapped as language-eloquent. Resting-state fMRI was acquired to provide a reference for comparing nrTMS-derived language maps. Outcomes: Electric-field-optimized nrTMS did not result in an increase in positively mapped ROIs. A different distribution of language errors was observed between sessions. Manual mapping roughly followed the extracted resting-state language and motor networks, whereas electric-field-optimized mapping might correspond less. Optimized coil positions were not always practically feasible. AR guidance improved target location accuracy. Conclusions: While AR was a useful addition to the TMS experiment, electric-field optimization did not translate into significant behavioral differences. However, altered distribution of language errors can give insight into underlying neurophysiological processes of rTMS. Full article

Radiation-induced bone injury, characterized by oxidative stress damage and impaired osteogenesis, lacks effective treatments. Exosome-based therapies have recently emerged as a safe and effective modality for radiation damage, and their functional capacity can be further potentiated through tailored preconditioning strategies—such as nanoparticle induction or physical stimulation. This study developed a novel exosome-based therapy by preconditioning bone marrow mesenchymal stem cells (BMSCs) with Iron oxide (Fe₃O₄) magnetic nanoparticles (MNPs, 50 µg/mL) and a static magnetic field (SMF, 100 mT). Exosomes derived from these preconditioned cells (BMSC-Fe₃O₄-SMF-Exos) exhibited enhanced yield and dual functionality. In irradiated BMSCs, BMSC-Fe₃O₄-SMF-Exos significantly promoted osteogenic differentiation, restoring alkaline phosphatase activity, mineralization, and expression of RUNX2, OCN, and COL1A1. They concurrently alleviated oxidative stress by scavenging reactive oxygen species, reducing malondialdehyde, and boosting superoxide dismutase activity. Mechanistically, miR-429 was found to be highly enriched in BMSC-Fe₃O₄-SMF-Exos, which directly targeted Noggin (NOG). Our functional validation experiments also confirmed that overexpression of miR-429 could inhibit NOG, alleviate oxidative stress and rescue the osteogenic differentiation of irradiated BMSCs. In conclusion, exosomes derived from preconditioning BMSCs with Fe₃O₄ MNPs and SMF mitigate radiation-induced damage via the miR-429/NOG pathway, presenting a promising cell-free strategy for bone regeneration. Full article

Low-field magnetic stimulation (LFMS) has been proposed as a non-invasive approach for modulating cortical oscillations through electromagnetic coupling. Frequency-aligned enhancement of alpha-band activity is of interest due to its association with cortical inhibitory balance and relaxed wakefulness. This study investigates whether a 10 Hz LFMS applied to the occipital area can induce measurable alpha-band modulation. Electromagnetic simulations were performed to determine magnetic flux distributions within a simplified spherical head model with magnetic susceptibility, which was approximating the brain’s parameters. The 10 Hz stimulation waveform—a positive ramp sawtooth—was analyzed in both time and frequency domains. Electroencephalographic (EEG) recordings were obtained before and after stimulation, and spectral analyses of relevant occipital channels were used to quantify the power redistributions. Simulations indicated localized magnetic field gradients in the occipital region. Post-stimulation EEG recordings showed a redistribution of spectral power toward the alpha-band, representing approximately 50% of total occipital spectral power, with relative increases exceeding 140% across the analyzed channels. These combined modeling and electrophysiological findings provide preliminary proof-of-concept evidence that frequency-aligned LFMS is associated with a redistribution of spectral power toward the alpha-band. Full article

Background: The phase of electroencephalogram (EEG) signals critically influences cortical reactivity to external inputs. Phase-dependent effects and their sensitivity to stimulation intensity have been observed at suprathreshold levels, while subthreshold transcranial magnetic stimulation (TMS) cannot induce motor evoked potentials (MEPs), resulting in limited research on phase-dependent responses under subthreshold stimulation. In this study, we used a combined transcranial magnetic stimulation and electroencephalography (TMS–EEG) approach to examine how the ongoing EEG phase influences cortical responses at subthreshold intensity and to characterize these responses in terms of temporal, spatial, and spectral features. Methods: Thirty-four healthy adults received subthreshold single-pulse TMS at the motor hotspot during 64-channel EEG recording. The mu-phase at the time of TMS delivery was estimated using autoregression-based forward prediction and categorized into four bins (0°, 90°, 180°, and 270°). The cortical responses were assessed using inter-trial phase coherence (ITPC), TMS-evoked potentials (TEPs), global mean field power (GMFP), and event-related spectral perturbation (ERSP). Results: Phase estimation reliably distinguished four mu-phase bins. Subthreshold TMS–EEG responses showed clear phase dependence: early ITPC and several TEP components (N15, P30, N45, P60, and N100) differed significantly across phases, with 180° and 270° often eliciting stronger responses. GMFP revealed robust phase effects at mid-latency components, and TMS-induced mu-rhythms were the greatest at 180°. Conclusions: Our results showed that the EEG phase significantly modulates cortical reactivity at subthreshold stimulation levels, supporting mu-phase-based closed-loop TMS as a promising strategy for precise neuromodulation. Full article