Search Results (318)

Seismic design of long-period reinforced concrete tall buildings is drift-dominated, and yet closed-form tuned mass damper (TMD) calibration lacks a rank-oriented robustness framework and a deterministic treatment of inelastic period drift. First, a two-layer closed-form calibration procedure is verified on 30-, 48- and 60-storey RC towers with periods of 3.80 to 8.45 s on a rock-like Istanbul site under eleven spectrum-matched records. The first layer, a Robust Tuning Index built on four design requirements, weighs nominal suppression against detuning robustness through a closed-form dominance condition and a unique crossover at the ±13% band. The second layer, a period-elongation-aware anchor, sets the calibration period to the mean of the elastic and DD-2 secant first-mode periods, capping the worst-case offset at ±9.0% to ±12.1% against +19.7% to +27.6% under elastic anchoring. Response-history analyses give mean peak roof-drift reductions of 2.8% to 4.6% with statistically inseparable formulation means at exact tuning, while the Sadek calibration cuts dispersion by more than a third and stroke by roughly a third, carries 2.3 to 2.5 times less frequency-response loss at the anchor offsets, and ranks first in 122 of 144 envelope scenarios. The framework replaces numerical retuning with a transparent closed-form route within the linear verification tier. Full article

Background: Obesity and mental disorders are associated with gut microbiota dysbiosis and gut–brain axis dysfunction. This secondary analysis evaluated the effects of a 12-week weight loss program (WLP) based on a hypocaloric traditional Mexican diet (TMD) and moderate-intensity exercise on gut microbiota, body composition (BC), and metabolic parameters in Mexican adults with obesity with and without depression and anxiety symptoms. Methods: A total of 106 adults with obesity were classified based on the presence or absence of depressive and anxiety symptoms into an obesity control group without symptoms (OCG), improved symptoms (OIS), and persistent symptoms (OPS). Stool samples were analyzed by sequencing the V3–V4 region of the 16S rRNA gene. Longitudinal changes in serum biochemistry, BC, intestinal permeability markers, and gut microbiota were analyzed using linear mixed-effects models. Differential taxa were identified using linear discriminant analysis effect size (LEfSe), and associations between bacterial genera, biochemical variables, and dietary components were explored using MaAsLin 2. Results: The WLP significantly improved metabolic, inflammatory, intestinal permeability, and BC markers, as well as depressive and anxiety symptoms, although participants remained in WHO grade I obesity. These improvements were accompanied by selective, group-dependent modulation of bacterial genera rather than broad microbiota restructuring. LEfSe identified 22 taxonomic biomarkers: 16 in OPS, 5 in OIS, and 1 in OCG. Conclusions: The culturally adapted WLP, which combined a hypocaloric TMD with exercise, promoted improvements in metabolism and BC in all participants, along with group-specific gut microbiota remodeling that may be associated with differential changes in depressive and anxiety symptoms in the context of persistent obesity. Full article

Two-dimensional heterostructures have attracted considerable attention in electrocatalytic hydrogen evolution due to their pronounced interfacial effects, tunable electronic properties, and large specific surface areas. In this work, two representative oxygen-terminated transition metal carbides (MXenes) and three typical transition metal dichalcogenides (TMDs) were selected to construct six heterostructures. Using first-principles density functional theory (DFT) calculations, their binding energies, structural stability, electronic structures, and HER catalytic performance were systematically investigated. The results showed that all heterostructures possessed good thermodynamic stability and favorable electronic properties. In particular, SnS₂/Ti₂CO₂, SnSe₂/Ti₂CO₂, SnTe₂/Ti₂CO₂, and SnTe₂/Zr₂CO₂ exhibited near-optimal hydrogen adsorption Gibbs free energy, indicating excellent HER activity. Moreover, the variation in Gibbs free energy of hydrogen adsorption from isolated monolayers to heterostructures could be effectively correlated with the work function difference. The predicted trends provided a useful descriptor for catalytic performance. Overall, this study provides theoretical insights into the rational design of efficient, advanced HER catalysts and contributes to the advancement of sustainable energy conversion technologies. As this work is based solely on first-principles calculations, the predicted catalytic activity of the heterostructure should be regarded as a theoretical prediction and awaits experimental confirmation. Full article

Background/Objectives: Temporomandibular disorders (TMDs) constitute an umbrella term encompassing a spectrum of conditions, including pain in the temporomandibular joint (TMJ), masticatory muscle pain, and restricted mandibular movement. The objective of the present study was to translate the Fonseca and TMD-7 questionnaires into Romanian, to assess their face validity, and to determine the reliability of the Romanian-language versions for use in the diagnosis of temporomandibular disorders (TMDs) and in subsequent epidemiological and clinical studies. A secondary objective was to establish a scoring scale for the TMD-7 questionnaire. Methods: Both questionnaires were translated from English into Romanian and back-translated by two independent teams of translators, after which the final versions were established for face validity assessment and reliability testing. Results: The study demonstrated reliability according to the Cronbach’s α coefficient, with values of 0.862 for the TMD-7 questionnaire and 0.840 for the Fonseca questionnaire. The scoring scale corresponding to the Fonseca questionnaire could not be implemented for the TMD-7 questionnaire. Conclusions: Both Romanian-language questionnaires demonstrated high corresponding Cronbach’s α coefficients; however, for clinical use, the Fonseca questionnaire will be utilized, as the TMD-7 questionnaire does not have a scoring scale. Full article

Two-dimensional molybdenum disulfide (MoS₂) has emerged as a promising candidate for next-generation electronics and optoelectronics; however, its scalable synthesis with precise control over domain size and film continuity remains challenging. Herein, we report a physical vapor deposition (PVD)-assisted chemical vapor deposition (CVD) strategy for the controllable growth of high-quality monolayer MoS₂. By thermally evaporating an ultrathin (3 nm) MoO₃ precursor film, spontaneous post-deposition dewetting yields a porous honeycomb morphology that significantly enhances vapor–solid reaction kinetics during subsequent sulfurization. Crucially, by modulating the argon carrier gas flow rate to regulate the local sulfur chemical potential, we achieve distinct growth regimes: a high flow rate (70 sccm) suppresses nucleation density, enabling isolated triangular and hexagonal single crystals with lateral dimensions up to 500 μm, whereas a reduced flow rate (50 sccm) promotes high-density nucleation and coalescence into continuous centimeter-scale polycrystalline films. Comprehensive structural and optical characterizations, including atomic force microscopy, Raman spectroscopy, photoluminescence, and X-ray photoelectron spectroscopy, confirm that the synthesized MoS₂ exhibits prototypical monolayer thickness (~0.7 nm), well-defined local crystallinity and a direct bandgap emission at 1.84 eV. This work establishes a robust, scalable, and highly tunable route for synthesizing large-area 2D TMDs tailored for advanced device integration. Full article

Andes virus (ANDV), a highly pathogenic orthohantavirus, enters host cells through low pH–triggered membrane fusion mediated by the Gc glycoprotein, a class II fusion protein containing a single C-terminal transmembrane domain (TMD). While the ectodomain has been extensively characterized, the role of the TMD in late-stage fusion remains unclear. Here, we investigated the minimal functional length and sequence requirements of the ANDV Gc TMD using site-directed mutagenesis. C-terminal deletion mutants and serine-to-alanine substitutions were evaluated for protein expression, virus-like particle production, cell–cell fusion, pseudotyped vector entry, and hemifusion activity. Deletion of the Gc cytoplasmic tail (CT) or a single C-terminal TMD residue was tolerated, whereas deletion of two or more residues impaired particle production and fusion, indicating that at least 21 of the 22 TMD residues are required for efficient membrane fusion and viral entry. Hemifusion assays showed that deletion of two or three residues, or substitution of the strictly conserved S1121, allowed lipid mixing but blocked progression to full fusion, while deletion of four residues also abolished hemifusion. In contrast, mutation of the less conserved S1126 had minimal effect. These results identify a precise TMD length and a conserved polar TMD residue as critical determinants of fusion pore formation in ANDV. Full article

Background/Objectives: Parkinson’s disease (PD) is a progressive neurodegenerative disorder characterised by motor and non-motor symptoms, including pain. Temporomandibular disorder (TMD)-like pain, defined as self-reported pain modified by jaw activities, has been suggested to be more prevalent in PD, but its association with PD severity remains unclear. This study aimed to investigate the association between pain modified by jaw activities and PD severity and the temporal stability of such pain in PD. Methods: This prospective study recruited 28 individuals with PD. Motor symptom severity and disability levels were evaluated using the modified Hoehn and Yahr (mHY) staging and modified Rankin Scale (mRS), respectively. Based on the diagnostic criteria for TMD, a questionnaire assessing pain modified by jaw activities and clinical examination were utilised. Pain modified by jaw activities was reassessed at one, two, and three months. Statistical analyses included Spearman’s rank correlation test and Friedman test, with p < 0.05 considered significant. Results: The participants’ mean age was 69.2 ± 9.6 years; 53.6% were male. Eight participants reported pain modified by jaw activities. Clinical examination identified painful palpation sites in 14 participants, most commonly in the masseter muscle body. Pain modified by jaw activity count showed significant positive correlations with mHY stage (rho = 0.48, p = 0.015) and mRS score (rho = 0.41, p = 0.04). Twenty-four participants completed follow-up, with no significant changes in pain reports over three months. Conclusions: Some individuals with PD may experience persistent TMD-like pain, which is correlated with motor symptom severity and disability levels, highlighting the importance of routine TMD screening in PD. Full article

This paper investigates the effects of two control measures on vortex-induced vibration and wake-induced vibration of suspension bridge cables through wind tunnel experiments. For a single cable, a passive suction/jet ring arrangement is proposed, and its vortex-induced vibration suppression performance under different density configurations (single-segment and two-segment dense arrangements) is analyzed. Experiments show that the total length of the ring is positively correlated with the control effect. The two-segment arrangement is significantly better than the single-segment arrangement when the total length is 1/4 of the cable length, with a maximum reduction in vibration displacement of 88%. For double cables, a spacer with an integrated tuned mass damper (TMD) is used. The results show that the TMD can effectively suppress vortex-induced vibration and wake-induced vibration. Its control effect depends on the installation position and the damper’s natural frequency. Installation at mid-span and 1/4-span positions can significantly reduce the vibration response, especially for suppressing first-order mode vibration. This study provides an optimized aerodynamic and damper combination scheme for cable wind vibration control. Full article

Top-heavy industrial towers, which carry large, concentrated masses of equipment at upper levels and feature open lower stories, are vertically irregular by design and tend to amplify seismic displacement and acceleration demands near the tower top. Although tuned mass dampers (TMDs) have been studied extensively for buildings, bridges and chimneys, their application to this particular class of slender industrial towers—where production-equipment vibration tolerance, retrofit accessibility and limited downtime drive the design—has received little dedicated attention. This paper reports a focused numerical investigation of seismic response mitigation for a 101.2 m molten-asphalt granulation tower retrofitted with a single pendulum-type TMD. A three-dimensional coupled finite element (FE) model was constructed in ABAQUS using C3D8R solid elements for the reinforced-concrete shaft and T3D2 truss elements for the embedded reinforcement; modal analysis returned a fundamental frequency of 0.912 Hz and a torsional-to-translational period ratio of 0.65, indicating a translational-mode-dominated response. Elastic time-history analyses under the El Centro and Taft records together with a code-spectrum-compatible synthetic accelerogram show that a pendulum TMD with mass ratio μ = 2.5%, tuning frequency offset Δf = 5% and damping ratio ξ = 10%—installed at the uppermost equipment level guided by the modal-displacement criterion—reduces the peak top displacement, peak top acceleration and peak base shear by roughly 23%, 23% and 22%, respectively, in both principal directions. The controlled top acceleration falls comfortably below the 2.94 m/s² operational tolerance of the on-tower melting equipment. To address the rationality of the chosen TMD parameters, a single-variable parametric sensitivity study spanning μ ∈ [1%, 5%], ξ ∈ [5%, 15%] and Δf ∈ [0%, 10%] is performed on an equivalent reduced model that captures the qualitative parameter-response trends; the chosen baseline values lie inside a stable performance plateau and are shown to be a balanced compromise among the three response measures. The principal contribution of the work is, therefore, (i) a complete TMD retrofit framework—modal-based placement, parameter design, coupled FE assembly and multi-record verification—adapted to top-heavy industrial towers, and (ii) qualitative evidence, supported by a sensitivity scan, with a robust proposed parameter set for small-to-moderate detuning. The study is restricted to elastic time-history analyses under frequent-earthquake-level excitation, three ground-motion records and a fixed-base assumption; nonlinear response, larger record sets and soil–structure interaction effects are explicitly identified as scope limitations and are left for follow-up work. Full article

In bridge widening projects under uninterrupted traffic conditions, vehicular vibration easily leads to damage in the interfacial transition zone (ITZ) and microstructural degradation of early-age concrete in wet joints. Taking a typical hollow slab-low T-beam widening structure as the object, this study introduces basalt micro fiber (BMF)-based ultra-high-performance concrete (UHPC) as the wet joint material and establishes a refined vehicle–bridge coupled dynamic model considering the time-varying stiffness of the joint material and road roughness excitation. The research indicates that although UHPC possesses excellent ultimate mechanical properties, its early-age setting process is extremely sensitive to vehicle-induced vibration. Numerical analysis reveals that while traditional temporary steel fixtures can effectively control the vertical relative displacement between the new and old girders within the critical value of 5.5 mm, the peak particle velocity (PPV) induced by heavy vehicles (buses and trucks) during the early pouring stage (<12 h) significantly exceeds the safety threshold of 3 mm/s, posing a severe threat to the directional distribution of steel fibers and interfacial bond strength. Therefore, this paper designs a single tuned mass damper (TMD) optimized based on Den Hartog’s fixed-point theory. Simulation results confirm that with the TMD configured, the vibration responses induced by buses across the entire speed range (≤120 km/h) are reduced below the safety limit; the vibration velocity induced by heavy trucks is also effectively controlled when combined with an 80 km/h speed limit. The collaborative strategy of “passive TMD vibration reduction + active traffic speed limit” proposed in this paper provides a theoretical basis for guaranteeing the early-age micro-forming quality of UHPC wet joints and overall traffic efficiency. Full article

Extracytoplasmic function (ECF) σ factors are central regulators of bacterial adaptation to environmental changes. The genome of Leptospira interrogans encodes 11 such factors, including LIC12757. Previous studies have shown that LIC12757 is regulated by the FecR-like protein LIC12756, forming a regulatory system similar to the Escherichia coli FecI-FecR system. Here, the domain-specific regulatory role of LIC12756 was investigated. Interactions between LIC12757 and several LIC12756 variants, including the N-terminal domain (NTD) alone, NTD with half or full transmembrane domain (NTD-TMD), and full-length LIC12756 (FL, control), were analyzed using the BACTH system. During logarithmic growth, interactions were detected only with FL and NTD-TMD, whereas in the stationary phase, all variants interacted with varying strengths. Pull-down assays using His₆-tagged NTD confirmed its direct binding to LIC12757. Promoter activity analysis revealed that the NTD alone functions as an anti-σ factor in the logarithmic stage of growth. However, it is insufficient for full activation of LIC12757-dependent transcription during the stationary phase, as observed with FL protein. The NTD-TMD variant caused only minor stimulation compared to FL. These results indicate that NTD is a key determinant of LIC12756’s anti-σ activity toward LIC12757, whereas full activation of LIC12757 requires additional extrinsic signals, which are likely sensed by the C-terminal extracytoplasmic region (ECR). These findings provide mechanistic insight into ECF σ factor regulation in L. interrogans. Full article

Objectives: To quantitatively assess masticatory function with instrumental measures in a group of patients suffering from temporomandibular joint (TMJ) arthralgia, and to compare the results with symptom-free controls. Methods: Data of bite force, variance-of-hue-based (VOH) chewing efficiency, chewing frequency, the bilateral pressure pain threshold (PPT) of the temporalis and masseter muscles, and mandibular range of motion (RoM) were collected in a sample of TMJ arthralgia patients (n = 14) and controls (n = 19). The diagnosis of arthralgia was obtained following the DC/TMD protocol. Comparison between the groups was conducted using independent samples t-tests (level of significance α = 0.05). Associations within the arthralgia group were assessed using Pearson’s correlation coefficient. Results: In comparison to the controls, arthralgia patients showed significantly restricted pain-free and maximum unassisted mouth opening (p < 0.001, p = 0.022 respectively) as well as a significant decrease in both bite force (p < 0.001) and chewing frequency (p = 0.01). The average chewing efficiency for the arthralgia group was 0.14 ± 0.08 VOH. The PPT for both masseter muscles did not show significant differences in comparison to the control group. Conclusions: In patients with TMJ arthralgia, functional markers such as RoM, bite force, and chewing frequency exhibited significant limitations compared to the control group. The employment of instrumental measurements in the documentation of symptoms in clinical practice provides an objective basis for the assessment of functional limitations. Hence, we recommend integrating them into the longitudinal patients’ observation during therapy. Full article

This paper presents a dynamic model of a top-tensioned riser (TTR) subjected to combined vortex-induced vibration (VIV) and time-varying tension excitation. The model employs a van der Pol oscillator to simulate load excitation caused by vortex shedding and incorporates a tuned mass damper (TMD) to suppress nonlinear vibrations in the riser. The key contributions include, first, employing the Galerkin method to obtain a multi-mode approximate solution and analyzing it using single-mode approximate equations, and subsequently, applying a multi-scale approach to investigate the vibration reduction effect of the TMD under two typical resonance scenarios. By introducing a complex impedance term derived from the complex transfer function, the physical effect of the TMD is transformed into a frequency-dependent dynamic reaction force coupled to the riser’s equation of motion. The first involves 1:1 internal resonance between the structural frequency and vortex-induced frequency, while the second involves 1:2 parametric resonance between the structural frequency and the top tension frequency. Results indicate that when the structural frequency exhibits 1:2 parametric resonance with the top tension frequency, complex bifurcation behavior occurs, leading to large-amplitude structural responses. Findings demonstrate that TMDs effectively alter the system’s stability distribution and exhibit outstanding vibration-reduction efficiency under both typical resonance conditions. Full article

With the development of modern structures in the direction of higher and more complexity, the existence of multiple factors in the design and requirements of structures can lead to structures prone to nonlinear properties. The tuned mass damper (TMD), a widely implemented passive control mechanism, plays a crucial role in the engineering field by effectively reducing vibrations within primary structures. Nevertheless, its deployment frequently induces nonlinear dynamics due to the substantial displacements resulting from TMD operation or the integration of limiting devices. This research delineates a computational framework for a single-degree-of-freedom nonlinear primary system regulated by a nonlinear tuned mass damper (NTMD), designed to emulate near-fault seismic phenomena via a sinusoidal load. The study concentrates on the nonlinear attributes of both the NTMD and the primary system. Utilizing the complex variable averaging method in conjunction with the multiscale technique, complex variable equations and slow invariant manifolds are formulated for the system under 1:1 resonance conditions, with their accuracy and validity substantiated through numerical simulations. Expanding upon the derived complex variable equations and slow invariant manifolds, this study examines the impact of nonlinear coefficients within the NTMD and the primary system on both the damping performance of the NTMD and the stability of the primary system. Furthermore, this research delves into the effects of mass ratio fluctuations on the damping effectiveness of the TMD and the control efficiency of the primary system, as well as the emergence of jump phenomena in the presence of significant nonlinear coefficients. The analytical outcomes underscore the critical need to account for the inherent nonlinearities in both the TMD and the primary system, which can have detrimental effects. By considering the mass ratio as a key design parameter, optimizing it can enhance the TMD’s vibration suppression capabilities and the primary system’s control behavior, while also reducing the likelihood of jump phenomena and improving overall structural stability. Full article

Background/Objectives: Temporomandibular disorders (TMD) are common in pediatric patients, yet limited data exist on orthodontists’ knowledge, confidence, and clinical practices related to pediatric TMD. This cross-sectional study aimed to characterize orthodontists’ perceived knowledge, confidence, training, and practice patterns, and examine associations between routine screening behaviors and perceived confidence. Methods: A 34-item anonymous survey was distributed to orthodontists and orthodontic residents enrolled in or graduated from U.S. Commission on Dental Accreditation (CODA)-accredited programs. The survey assessed perceived knowledge, confidence in screening, diagnosis, and management of pediatric TMD, adequacy of residency training (on 0–10 numerical rating scale), frequency of routine TMD screening and examination practices, and referral patterns. Respondents were compared in study outcomes according to years of clinical practice with ANOVA. Respondents were categorized according to frequency of TMD screening (always/some of the time vs. sometimes/never) and compared in study outcomes using independent t-tests. Results: Out of 83 respondents, perceived knowledge (56.8 ± 26.9), confidence with screening (62.0 ± 30.5), diagnosis (59.4 ± 29.8), and management (50.8 ± 30.9) of pediatric TMD were moderate. Less than half of respondents (45.8%) reported routinely screening pediatric patients using standardized screening questions. Orthodontists who reported routine screening demonstrated significantly greater perceived knowledge and confidence in screening, diagnosis, and management compared with those who screened less frequently (all p’s ≤ 0.018, effect size between 0.57 and 0.78). Greater use of specific history-taking and clinical examination components was also associated with higher perceived confidence (all p’s between 0.001 and 0.046, effect size between 0.53 and 1.01). Confidence differed by years in practice, with lower scores reported among residents and mid-career practitioners (p < 0.05). Conclusions: Variability exists in orthodontists’ perceived knowledge, confidence, and clinical practices regarding pediatric TMD. Routine screening was associated with greater perceived competence. These findings highlight potential alignment between structured screening behaviors and self-reported confidence and may inform educational strategies in orthodontic training. Full article