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.
Piezoelectric pressure sensors are commonly used as blast wave pressure sensors in explosion testing. Accurate measurement of blast wave overpressure is of great significance. In explosion testing, piezoelectric pressure sensors exhibit a baseline drift phenomenon. This paper analyzes the mechanism of the baseline drift phenomenon observed in explosion testing through experiments and simulation, identifying the mechanism behind it. From an experimental perspective, it is determined that the thermal effect of light induces the baseline drift phenomenon. Furthermore, modeling and simulation of the piezoelectric pressure sensor using COMSOL 6.2 Multiphysics software confirms that the photothermal effect causes changes in the temperature field within the sensor's internal structure, which in turn brings the thermal stress. The thermal stress superimposes on the output of piezoelectric pressure sensors. This is the fundamental cause of the baseline drift phenomenon in piezoelectric pressure sensors. This research provides a crucial foundation for understanding the mechanisms by which explosions affect piezoelectric pressure sensors.
Background: Neuropsychiatric manifestations are a recognized complication of COVID-19, yet their temporal evolution across pandemic waves remains poorly characterized in hospitalized cohorts. This study examined whether their prevalence and composition changed across five successive waves. Methods: We conducted a retrospective observational study of 1471 hospitalized adults with confirmed Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection at Sibiu County Emergency Clinical Hospital, Romania (March 2020-January 2025), spanning ancestral through Omicron variants. A custom natural language processing pipeline extracted symptoms, medications, and International Classification of Diseases, 10th Revision (ICD-10) codes from electronic medical records. Nine hierarchical clinical clusters were defined; temporal trends were assessed using multivariable logistic regression with age-stratified replication. Results: Severe neurological presentations (stroke, seizures, hemiparesis) increased six-fold from 3.5% in Wave 1 to 20.1% in Wave 5, while psychiatric symptoms (anxiety, insomnia) declined from 13.3% to 4.3%. Overall, neuropsychiatric burden remained stable (~40-45%), revealing a compositional shift. This neurological trend persisted after multivariable adjustment (adjusted odds ratio 4.34, for Wave 5 vs. Wave 1) and within age-stratified subgroups, was inversely associated with respiratory severity and could not be attributed to vaccination status. The composite neurological severity index independently predicted mortality and intensive care unit admission. Conclusions: Neuropsychiatric manifestations in hospitalized Coronavirus disease of 2019 (COVID-19) patients underwent a compositional shift from psychiatric dominance in early waves to severe neurological dominance in later waves, consistent with a transition from reactive psychiatric presentations toward progressive neurological injury. This pattern, largely independent of measured confounders, underscores the need for sustained neurological surveillance beyond the acute respiratory phase.
ImportanceEvidence regarding the mechanism of tinnitus in patients with normal full-frequency hearing remains limited. This study investigated the auditory brainstem response (ABR) waveform patterns in these patients to address this unmet need, which is of considerable assistance in the clinical management of tinnitus with normal hearing.ObjectiveThis study aims to investigate the potential underlying mechanisms of tinnitus with normal full-frequency (125 Hz-16 kHz) hearing threshold by analyzing waveform alterations in ABR among tinnitus patients.DesignCross-sectional study.SettingOtolaryngology outpatient of a tertiary referral hospital.ParticipantsPatients aged 20 to 40 years with unilateral subjective tinnitus and normal hearing (pure-tone thresholds ≤25 dB HL across 0.125-16 kHz) were recruited. Age-matched healthy volunteers with normal full-frequency hearing (0.125-16 kHz) and without tinnitus served as controls.ExposuresParticipants were categorized according to the presence of unilateral subjective tinnitus.Main Outcome MeasuresThe primary outcomes included pure-tone audiometry testing (0.125-16 kHz) and ABR testing using 80 dB nHL click stimuli with alternating polarity (19.9 Hz, 1024 scans).ResultsThe study included 136 adult subjects with normal hearing at all frequencies, including 60 unilateral tinnitus patients and 76 normal volunteers. Results showed no significant differences in ABR waveform characteristics between affected and unaffected ears in unilateral tinnitus patients ((P > .05). However, compared with normal volunteers, unilateral tinnitus patients exhibited significantly prolonged latencies of waves I, III, and V on the tinnitus side (all P < .05), with median differences (95% CI) of 0.08 (0.04-0.11), 0.07 (0.00-0.12), and 0.15 (0.09-0.20), respectively. In addition, the interpeak latency between waves III and V was also prolonged, with a median difference of 0.08 (95% CI: 0.03-0.13).ConclusionTinnitus patients with normal full-frequency hearing exhibit differences in the ABR waves, which may be associated with abnormal middle ear muscle activity. Emotional responses may trigger abnormal middle ear muscle activity via the serotonin system, which in turn affects auditory signal transmission through the trigeminal system, leading to tinnitus and abnormal ABR wave patterns.RelevanceFuture research will focus on the middle ear muscles as a potential breakthrough point, exploring the relationship between abnormal electrical activity in these muscles and tinnitus, as well as the electrical activity of the trigeminal nerve nuclei.Level of Evidence3.
Metamaterials possess high freedom on structural design, yet their ability to modulate electromagnetic waves is subject to intrinsic constraints that are independent of specific meta-atom geometries. The constraints are revealed by analyzing the statistical amplitudes and phases of transmission and reflection wave in some representative metamaterials. Based on scattering theory, a reconstructed and more general description of the electromagnetic modulation process in metamaterials is established. Two explicit and geometry-independent corollaries concerning the coupling between transmission and reflection waves are further obtained and verified. The results provide a new perspective on the fundamental modulation mechanism of metamaterials on electromagnetic waves.
To overcome the persistent challenges in current angle-selective technologies, particularly the trade-off between structural compactness and dynamic tunability, a one-dimensional magnetic photonic crystal is introduced. The proposed structure leverages the magnetoplasmonics of epsilon-near-zero (ENZ) Indium Arsenide to achieve a sharp angular cutoff via magnetically tunable total internal reflection. The proposed configuration, composed of ENZ Indium Arsenide and dynamic anti-reflection structures (AFS), is designed to operate based on the principles of total internal and Bragg reflection. Theoretical calculations, performed via the transfer matrix method, show that the engineered AFS mitigates material resonance defects. This creates a rectangular transmission window surpassing 0.9 across a ± 55° wide-angle range and demonstrates exceptional polarization and angular robustness. Moreover, the application of an external magnetic field enables the dynamic separation of transverse electric (TE) and transverse magnetic (TM) waves. The magnetic field selectively compresses the angular passband of TM waves through the Lorentz force, while TE waves remain fundamentally unperturbed, thereby allowing for dynamic switching among three operational modes comprising dual polarization transparency, polarization separation, and total blocking. Furthermore, this magneto-optical effect is also evident in the frequency domain, where the elevation of the TM wave passband to higher frequencies creates a tunable TE passband filter. Consequently, the proposed design offers an innovative framework for high-performance, multifunctional optical switches, polarization splitters, and dynamic filters.
Ordered phases give rise to collective modes and quasiparticles, such as spin waves and magnons emerging from magnetic order. Extending this paradigm to ferroelectrics suggests the existence of polarization waves and their fundamental quanta, ferrons. A coherent ferron-that is, a polarization wave-modulates the magnitude of the electric polarization and is thus an amplitude (Higgs) mode of the ferroelectric order. Here we observe coherent ferrons from the pulsed laser excitation of van der Waals ferroelectrics, NbOI2 and WO2Br2. We demonstrate two complementary manifestations of coherent ferrons: intense narrow-band terahertz emission at the ferroelectric transverse optical phonon frequency, and uniaxial propagation along the polar axis as hyperbolic phonon polaritons with exceptionally long coherence times. These long-lived, uniaxial and dipole-carrying polarization waves may find applications in narrow-band terahertz emission, ferronic information processing and coherent electric control.
Background and Objectives: represents a major public health challenge in rapidly aging societies. While lifestyle behaviors are established modifiable risk factors for frailty, the longitudinal impact of composite lifestyle trajectories-particularly by sex-remains poorly understood. This study examined sex-stratified associations between Healthy Lifestyle Score Trajectories (HLSTs) and frailty among community-dwelling middle-aged and older adults in South Korea. Using 19 years of nationally representative panel data from the Korean Longitudinal Study of Aging (2006-2024), we analyzed 6603 participants (2684 males; 3919 females). Materials and Methods: Group-Based Trajectory Modeling was applied to Waves 1-6 to derive sex-specific HLSTs based on smoking, alcohol consumption, physical activity, and body mass index. Generalized Estimating Equations were used to assess longitudinal associations between HLSTs and Frailty Index (FI) scores across Waves 6-10, adjusting for sociodemographic covariates. Results: Five distinct HLSTs were identified in both sexes. In both males and females, persistently poor or deteriorating trajectories were independently associated with higher FI scores relative to the Favorable HLST reference group. The effect size for Poor HLST was more than twice as large in females (B = 0.039) than in males (B = 0.018), consistent with the sex-frailty paradox. Among females, the Improving HLST group did not demonstrate a statistically significant frailty benefit (B = 0.014, p = 0.091). Stratified analyses revealed that the lifestyle-frailty association among males was significant only in rural-dwelling participants, whereas in females the association was consistent across both urban and rural settings. Conclusions: Persistently unfavorable composite lifestyle trajectories were independently associated with higher frailty burden, with disproportionately greater impact in women. Late-life lifestyle improvement was not significantly associated with reduced frailty in women, reinforcing the importance of early and sustained behavioral maintenance. The rural-specific association in men highlights the role of structural disadvantage in amplifying lifestyle-related frailty risk. However, given the observational design of this study, the possibility of reverse causality cannot be excluded, and these findings should be interpreted as associative rather than causal. These findings support sex-sensitive, trajectory-based, and geographically tailored frailty prevention strategies.
Ultrasonic motors have attracted considerable attention in precision actuation applications because of their advantages over conventional electromagnetic motors, such as compact structure, high positioning accuracy, immunity to electromagnetic interference, noise-free operation, and suitability for low-temperature environments. However, conventional traveling-wave linear ultrasonic motors usually rely on boundary constraints to establish stable traveling waves, which may limit their structural flexibility and self-propelled capability. To address this issue, this paper proposes a free-boundary traveling-wave linear ultrasonic motor capable of realizing self-propelled motion. The motor features a projection structure at each end of the stator. Two piezoelectric ceramics are placed at one end for excitation, while a damping material is arranged at the other end for energy absorption. This design enables the motor to generate traveling waves without requiring fixed boundary conditions. The motor operates in the B(3,1) out-of-plane vibration mode to enhance the energy absorption capacity of the non-excited end and reduce its standing wave ratio (SWR). A finite element model of the motor is established to investigate its vibration characteristics. In addition, a novel method for estimating the standing wave ratio is proposed by using piezoelectric ceramics attached to the motor surface, replacing the traditional calculation approach. A prototype is fabricated to verify the feasibility of the proposed design. Experimental results show that the prototype achieves a minimum SWR of 1.81, a no-load speed of 42.1 mm/s, and a maximum output force of 0.465 N. These results confirm the feasibility of the proposed scheme and provide a new approach for the design of free-boundary traveling-wave linear ultrasonic motors.
What is believed to be a new phenomenon - plasma-based thermally-induced optical reflection of sound (P-THORS) - overcomes the limitations of traditional THORS (e.g. need for line-of-sight, concentration dependence, and variations in efficiency at distance) by using a laser to generate a shaped plasma for the formation of highly-efficient, variable geometry, free-space acoustic reflector/barrier. These reflectors allow for the focusing and steering of acoustic waves without the need of a continuous barrier or engineered materials. This work demonstrates for the first time the generation of P-THORS barriers with highly efficient reflection efficiencies, exceeding those of traditional THORS barrier (i.e. > 70%) as well as the ability to transiently shape the barrier into various geometries to steer the acoustic wave to specific locations. P-THORS barriers are shown to reflect near 100% of incident ultrasonic signals and maintain that reflectivity for 5 ms post-plasma formation. Furthermore, by shaping the plasma it was possible to selectively direct the ultrasonic and/or acoustic waves to a desired location with efficiencies of 30% or greater, depending on the geometry of the shaped plasma.
Background: Intravascular lithotripsy (IVL) has emerged as a novel vessel preparation device for patients with peripheral artery disease undergoing angioplasty. The IVL catheter includes an integrated balloon, which emits high pressure and transient sonic waves. The release of shockwaves results in cracking of intimal and medial calcium within the vessel wall improving lumen patency. Objectives: The aim of this prospective observational cohort study is to evaluate the morphological and imaging changes in atherosclerotic plaque in patients with PAD undergoing IVL as a vessel preparation technique, followed by angioplasty with drug-coated balloon (DCB) or stent placement if required. Secondary endpoint is to evaluate the efficacy of IVL in the perfusion of the lower extremities, by calculating the ankle-brachial index (ABI) and toe-brachial index (TBI) post-angioplasty, as well as adverse events within 30 days. Methods: Consecutive adult (≥18 years of age) patients with symptomatic femoropopliteal artery disease selected to undergo IVL will be included in the study. Computed tomography angiography (CTA) of the lower limbs will be performed pre- and postoperatively. Intraoperatively, an intravascular ultrasound (IVUS) will be used before and immediately post-angioplasty, for real-time evaluation of the morphological and quantitative changes in the atherosclerotic plaque. All participants will be clinically re-evaluated in 30 days postoperatively and a color Duplex ultrasound of the lower extremity arteries will be performed. The perfusion of the peripheral arteries will be assessed using ABI and TBI post-procedurally. Outcomes: The primary outcome is the quantitative assessment of changes in plaque morphology and volume within the index target lesion, based on pre- and post-procedural computed tomography angiography using TeraRecon™ (Durham, NC, USA) plaque analysis module, reflecting plaque modification and redistribution, in the context of IVL-based vessel preparation. Secondary outcomes include improvement of peripheral arterial perfusion and freedom from clinically driven target lesion revascularization (CD-TLR) and major adverse events.
Socio-economic and demographic variables have been identified as determinants of transmission of, and susceptibility to, COVID-19. In this study, we analyse the heterogeneous impacts of non-pharmaceutical interventions on the socio-economic and demographic (SED) variables driving COVID-19 incidence in Toronto during the 2nd, 3rd and 4th waves of the pandemic. Spatial autoregressive models were used to explore associations between COVID-19 incidence and SED variables at neighborhood scale, accounting for vaccination levels. This approach helps clarify how SED factors and vaccine coverage drive COVID-19 incidence and how non-pharmaceutical interventions (NPIs) modulate these factors at neighborhoods' level, while taking into account the pervious nature of boundaries at these scales to disease transmission due to population mobility, although without directly informing on behaviours, exposure, or vulnerability at individual level. Three distinct models were considered for each of the second, third and fourth COVID-19 waves, from late 2020 to late 2021. Associations highlighted by the models were interpreted with reference to the NPIs implemented. Level of scholarity, income, proportion of the population living alone, average number of children in families, and the proportion of the population whose mother tongue is not an official language showed significant relationships with COVID-19 incidence. Model results were different for each wave, reflecting the unequal impacts of NPIs at different time points, and for different population groups, depending on the nature of interventions and the SED determinants considered. Prioritization of population groups for testing, unequal gathering restrictions, selective closure of economic activities or work-from-home policies led to heterogenous impacts on incidence. The results highlight the unequal burden of the pandemic across populations and likely disparities in occupational exposure driven by SED factors, as well as their evolution with the implementation and lifting of NPIs. Populations with the lowest income and scholarity cumulate the highest risks of exposure and the highest risks of severe disease outcomes. Our results support the development of knowledge based public health surveillance programs integrating both non-communicable and infectious diseases cases, beyond their acute occurrences, along with their socio-economic characteristics.
High-pressure hydrogen storage has become the mainstream technical route for fuel cell vehicles due to its high energy density and favorable economic efficiency, with operating pressures gradually increasing from 35 to 70 MPa. However, the complex shock wave structures formed during high-pressure leakage pose significant challenges to numerical simulation. Existing CFD models based on incompressible assumptions or low Mach number conditions are prone to numerical oscillations, nonconvergence, or even computational failure when dealing with the strong nonlinearity and solution discontinuities induced by intense shock waves. Conventional numerical schemes often face a dilemma: low-dissipation schemes may introduce nonphysical oscillations, whereas high-dissipation schemes tend to excessively smooth shock structures, leading to distorted flow characteristics and reduced prediction accuracy. In this study, a numerical model for high-pressure hydrogen jet diffusion is established by considering the functional relationship between the influence range of shock waves at discontinuities and the time step. Validated through 70-MPa schlieren experiments, the model predicts the Mach disk position with an error of 8.7%. The research indicates that local low-pressure zones as low as 25,000 Pa appearing in the flow field significantly reduce the critical autoignition temperature of hydrogen, and the flammable range is primarily concentrated at the wrinkled edges of the hydrogen cloud and near-wall "air entrapment zone." These findings provide a quantitative basis for optimizing the placement of leak detection sensors and designing explosion venting solutions.
Timely detection of localised COVID-19 surges is essential for targeting limited health resources, yet most routine surveillance algorithms ignore spatial dependence and many Bayesian spatio-temporal models are computationally demanding. Evidence on Hamiltonian Monte Carlo (HMC) performance for outbreak detection in low- and middle-income country (LMIC) settings remains limited. We applied a Bayesian spatio-temporal hidden Markov model (HMM) to South African COVID-19 hospital mortality, comparing data-augmented Markov chain Monte Carlo (MCMC) with dynamic HMC. We conducted a retrospective ecological time-series study of in-hospital COVID- 19 deaths across 52 districts over 28 months (March 2020-June 2022), using national hospital surveillance linked to district-level health-system and population indicators. Death counts were modelled with a Poisson log-linear specification incorporating a smooth temporal trend, cyclic seasonality, spatial smoothing, and selected covariates, offset by expected deaths from admissions and a case-fatality ratio. Outbreaks were represented by a two-state HMM with latent indicators integrated out analytically and estimated via dynamic HMC in Stan. Eight candidate models were ranked using marginal likelihoods; the preferred model was re-fitted with both samplers to compare runtime, ESS, and convergence. A spatial HMM with marginalised outbreak states was strongly favoured over nonoutbreak and threshold-based alternatives. Posterior outbreak probabilities reproduced the four recognised national waves while revealing marked district-level heterogeneity, with early intense outbreaks in Western Cape and Gauteng districts and later peaks inland. Outbreaks were short-lived (mean around three months), and residual spatial risks indicated persistent excess mortality in the Eastern Cape and Free State. Dynamic HMC and MCMC yielded similar outbreak probability surfaces; however, HMC produced substantially larger ESS 1 (approximately 5,000 versus 63) and near-ideal convergence, whereas MCMC showed poor mixing. ESS per second was similar, so HMC's extra computation yielded more informative samples. A Bayesian spatio-temporal HMM fitted with dynamic HMC delivers coherent, spatially resolved outbreak probabilities and captures short-lived district-level mortality surges within broader national waves. Despite greater computational intensity, dynamic HMC offers superior mixing and convergence and is preferable for routine surveillance when adequate computing resources are available. The framework is transferable to other routinely collected surveillance data in South Africa and similar LMIC settings.
Central auditory processing efficiency is considered a predictor of how well children can learn to read, with the Frequency Following Response (FFR) serving as a sensitive biomarker of neural speech encoding ability. However, data regarding the 170 ms [da] stimulus in children who are native speakers of Brazilian Portuguese (BP) remain limited. This study investigated FFR results in 37 typically developing, normal-hearing children aged 8 to 10 years. Participants underwent audiological, behavioral, and academic performance screenings, followed by monaural FFR recording (using a 170 ms [da] stimulus at 80 dBnHL). Linear mixed models (LMM) were used to examine the effects of age, sex, and ear on the latencies of waves V, A, D, E, F, and O. The analysis revealed a medium effect size for waves D, E, and F, regarding the Ear factor, though statistical significance was specifically observed for wave E. For this wave, sex was also associated with a medium effect size, characterized by longer latencies in female participants. While the results for age did not reach broad statistical significance, the presence of medium effect sizes in wave E may suggest ongoing refinement of neural synchrony and asymmetric maturation during this developmental period. This study contributes to the characterization of neural speech encoding in the Brazilian Portuguese-speaking children and may support future investigation involving auditory processing disorders and learning difficulties.
Epidemic waves in large metropolitan areas unfold heterogeneously across territories shaped by persistent socioeconomic inequalities. Explaining how transmission intensifies, stabilises, and shifts across the urban landscape remains a central challenge in epidemiology. This study develops a covariate-dependent, non-homogeneous Hidden Markov Model (nHMM) to infer latent transmission regimes from municipality-level COVID-19 incidence in Santiago, Chile. The framework links daily case dynamics to mobility flows and structural socioeconomic indicators within a hierarchical specification that captures inter-municipal heterogeneity. Model selection identifies three statistically distinct and epidemiologically interpretable regimes corresponding to moderate, severe, and critical transmission phases. Transition dynamics reveal marked spatial asymmetries: while increases in mobility consistently elevate escalation risk, structural conditions-such as overcrowding and deficits in urban infrastructure-substantially influence both the probability of entering and the persistence within high-severity regimes. To ensure epidemiological interpretability, regime-conditioned incidence trajectories are mapped to the time-varying reproduction number ([Formula: see text]) through a renewal formulation, enabling coherent propagation of uncertainty from latent-state inference to transmission estimates. By integrating latent regime inference with hierarchical transition modelling and renewal-based transmission analysis, this study distinguishes structural phase shifts from stochastic variability in urban epidemic dynamics. The findings clarify how mobility and entrenched inequality jointly structure transmission risk, providing a scalable and transferable framework for monitoring and anticipating epidemic regime transitions in complex metropolitan systems.
In order to study the noise reduction performance of Porous Elastic Road Surface (PERS), the vibration noise and air pumping noise has been separated from the tire-road noise through the finite element numerical simulation method. The tire-road noise model among the tire, road and surface air has been constructed by coupling of acoustic waves. The characteristics of tire-road noise under the PERS, Porous Asphalt Concrete (PAC), and Asphalt Concrete (AC) pavements have been analyzed through the modelling. The tire-road noise has also been investigated through the noise field tests. The generating process, coupling characteristics, and noise reduction performance of the vibration noise and the pumping noise of PERS pavements has been revealed. The results show that the tire-road noise was mainly generated by the vibration noise under the vehicle speed below 80 km/h. The proportion of pumping noise gradually exceeds that of vibration noise under the vehicle speed greater than 90 km/h. And the pumping noise gradually played the major role in the tire-road noise, which also increased with the increasing of vehicle speed. Comparing with AC and PAC pavements, PERS pavement exhibited the obvious advantages in noise reduction. Additionally, the reliability of the tire-road noise model has been verified through the field noise tests. It is expected that this work will serve as a reference for future research on the mechanics of the generation of tire-road noise, and try to provided theoretical support for the application of PERS.
Poor intimate relationship quality is prospectively associated with elevated levels of depressive symptoms and higher incidence of a major depressive episode. Propensity score matching analyses, which statistically equate people in the exposure sample (e.g., people in distressed relationships) with a comparison sample (e.g., people in nondistressed relationships), provide a complementary means to traditional covariate analyses for addressing confounding in observational research, thereby enhancing the ability to evaluate potential causal associations. In this preregistered study, propensity score matching analyses were conducted using a probability sample of married adults in the United States aged 50 years and older who participated in 2014/2016 or 2016/2018 waves of the Health and Retirement Study and who were (a) not depressed at baseline and (b) continuously married at baseline and 2-year follow-up. Women (n = 407) and men (n = 525) in distressed relationships were matched with an equal number of women and men in nondistressed relationships on the propensity to experience relationship distress. Women and men in distressed relationships were significantly more likely than propensity-matched women and men in nondistressed relationships to meet criteria for a past-year major depressive episode at follow-up. In the full sample of women (n = 2,273) and men (n = 2,345), similar results were obtained for covariate analyses using the propensity score as well as traditional covariate analyses examining covariates independently. Findings provide strong support for the perspective that relationship distress is causally associated with depression and support the use of couple-based interventions for preventing and treating depression in middle-aged and older adults. (PsycInfo Database Record (c) 2026 APA, all rights reserved).
As an artificial two-dimensional (2D) metamaterial, metasurface has been widely studied for its ability to regulate electromagnetic waves through simple structures. However, traditional metasurfaces make it difficult to modulate different polarizations by a single device, let alone the reasonable allocation of energy to multiplexed polarizations, which is not suitable for comprehensive applications in multifunctional integrated system. Here, a full polarization multiplexing scheme and power-target-field-based addition theory for multiple beams, and an interference reduction scheme are theoretically proposed and experimentally achieved using anisotropic metasurfaces. The full polarization multiplexing scheme achieves different linearly polarized and circularly polarized beams using the same feed and tensor units with a simple design for the first time. The proposed addition theory modifies the existing scheme to achieve performance improvement and accurate energy allocation for multiple beams. The interference reduction scheme can control the propagation orientation and initial position of multiple beams, and finally achieve multi-dimensional control. All methods are verified by achieving 2D Airy beams, and the relationship between modulation function and the surface impedance that reflects material characteristics is studied. The anisotropic metasurfaces provide multiplexing functions using multiple beams with orthogonal polarization states and controllable power levels, which represents a simple and effective transmitting end for multi-functional systems and multiple targets in wireless transfer systems.
Background: Frailty is a fluctuating health state that may worsen or improve over time and is linked to adverse outcomes, including musculoskeletal disorders such as arthritis. However, evidence on whether frailty changes predict arthritis onset remains limited. This study examined the relationship between changes in frailty status and incident arthritis among Chinese adults aged 45 years and older. Methods: We performed a longitudinal cohort analysis using data from the China Health and Retirement Longitudinal Study (CHARLS). Frailty was quantified with a 30-item Frailty Index (FI) and categorized as robust, pre-frail, or frail. Frailty transitions were defined by changes in FI-based categories across survey waves. Incident arthritis was identified as self-reported physician-diagnosed arthritis during follow-up. Associations between frailty transitions and arthritis onset were evaluated using Cox regression, reporting hazard ratios (HRs) and 95% confidence intervals (CIs). Models were adjusted for demographic characteristics, health behaviors, and biochemical indicators, and sensitivity analyses were conducted to verify result stability. Results: Among 4982 participants (mean age 58.97 years; 45.58% female). Relative to robust individuals, baseline pre-frailty (HR 1.67, 95% CI 1.41-1.97) and frailty (HR 2.76, 95% CI 1.97-3.85) were associated with higher arthritis risk. Participants whose frailty status worsened from robust to pre-frail or frail also showed higher arthritis risk (HR 1.68, 95% CI 1.34-2.10). In contrast, transitions from frail to pre-frail or robust were associated with lower risk (HR 0.44, 95% CI 0.21-0.92). Higher cumulative frailty burden and greater frailty progression were also associated with increased arthritis risk. Conclusions: Frailty transitions are strongly associated with incident self-reported physician-diagnosed arthritis. Monitoring frailty trajectories may improve arthritis risk stratification and support prevention strategies.