Search Results (255)

Metamaterials, characterized by engineered microstructures rather than chemical composition, are transforming civil infrastructure through their unique ability to achieve frequency-selective wave attenuation and programmable mechanical responses. This review provides a comprehensive overview of the applications of acoustic and mechanical metamaterials within civil engineering contexts. Acoustic metamaterials demonstrate significant potential for mitigating noise pollution in environments such as high-rise buildings, urban public areas, and transportation infrastructure by substantially enhancing sound insulation and noise reduction capabilities. Meanwhile, mechanical metamaterials, exhibiting advanced properties including shape memory, exceptional stiffness, and programmable functionality, offer novel strategies for improving structural resilience and seismic performance. Additionally, this article explores emerging opportunities in energy harvesting and adaptive infrastructure integration. Despite these advancements, critical challenges related to scalability, durability, and seamless integration with the existing infrastructure persist. Addressing these issues in future research will facilitate the advancement of sustainable, adaptive, and high-performance metamaterial solutions for modern civil infrastructure. Full article

Background: Gut microbiota dysregulation is increasingly recognized as a key contributor to the progression of liver cirrhosis and its complications, particularly hepatic encephalopathy. Fecal microbiota transplantation (FMT) has emerged as a novel therapeutic strategy aimed at restoring intestinal microbial homeostasis and modulating systemic inflammation. Methods: This prospective, single-center clinical trial evaluated the short-term safety and efficacy of FMT in patients with alcohol-related liver cirrhosis. Clinical assessment, liver stiffness (via elastography), steatosis (controlled attenuation parameter), inflammatory biomarkers, and extended biochemical panels were analyzed at baseline, one week and one month post-FMT. A control group receiving standard medical therapy was used for comparison. Results: FMT was associated with a significant reduction in hepatic encephalopathy severity (p = 0.014), sustained improvements in liver stiffness (p = 0.027) and decreased steatosis (p = 0.025). At one month, C-reactive protein and neutrophil-to-lymphocyte ratio both declined significantly (p = 0.043), indicating a measurable anti-inflammatory effect. No serious adverse events were recorded. In comparison with controls, FMT recipients showed lower systemic inflammation and improved neuropsychiatric status. Conclusions: FMT demonstrated a favorable safety profile and yielded early clinical and biochemical benefits in patients with cirrhosis. These preliminary findings support the potential utility of microbiota-based interventions in chronic liver disease and warrant validation in larger, multicenter trials. Full article

The progression of metabolic dysfunction-associated steatotic liver disease (MASLD) to severe forms, including metabolic dysfunction-associated steatohepatitis (MASH) and liver fibrosis, involves metabolic dysfunction, genetics, and gut dysbiosis. People with HIV (PWH) represent a high-risk group for MASLD, but the role of gut microbiota alterations in disease severity within this population remains poorly understood. We prospectively recruited PWH with MASLD, defined as the controlled attenuation parameter (CAP) ≥ 238 dB/m, and excluded those with viral hepatitis coinfection or alcohol abuse. Severe MASLD was defined as the presence of MASH (cytokeratin-18 ≥ 130.5 U/L) and/or significant liver fibrosis (liver stiffness ≥ 7.1 kPa). Stool samples were collected for 16S rRNA gene sequencing to characterize gut microbiota composition. Functional predictions were generated using PICRUSt. The differential abundance of bacterial taxa and predicted functions were analyzed using a generalized linear model with a negative binomial distribution. Among 34 PWH with MASLD, 18 (53%) met the criteria for severe MASLD. Microbiota profiling revealed significant differences in bacterial genera between the PWH with and without severe MASLD. Enrichment was observed in the Ruminococcus gnavus group, Negativibacillus, Holdemanella, Subdoligranulum, the Eubacterium hallii group, and Butyricicoccus, while depletion was seen in Prevotella, Alloprevotella, Dialister, Catenibacterium, the Christensenellaceae R 7 group, Clostridium sensu stricto, Olsenella, Oscillospiraceae UCG-005, Libanicoccus, and the Eubacterium siraeum group. Predicted functional pathways related to fatty acid degradation, folate biosynthesis, and amino acids metabolism did not differ between groups. MASLD severity in PWH is associated with a distinct gut microbiota signature, though not with functional pathway alterations. Microbial profiling may complement existing non-invasive biomarkers for risk stratification in this high-risk population. Full article

Background/Objectives: The growing prevalence of metabolic-associated steatotic liver disease (MASLD)/metabolic-associated steatohepatitis (MASH) is forecasted to be over 55% by 2040, representing a significant driver of cirrhosis and highlighting demand for effective therapeutic interventions. The therapeutic landscape is evolving with agents, like glucagon-like peptide-1 receptor agonists (GLP-1 RAs), under active investigation. A common concern across emerging therapies is potentially precipitating decompensation in patients with existing cirrhosis, necessitating careful consideration in this population. Case Presentation: A 46 y.o. female with obesity and cirrhosis from MASH and alcohol who underwent a deceased-donor liver transplant developed steatohepatitis within a year post-transplant after gaining 36 kg. Transient elastography revealed controlled attenuation parameter (CAP) 400 dB/m (S3 steatosis) and liver stiffness measurement (LSM) 61.2 kPa (advanced fibrosis). Follow-up biopsy confirmed severe steatohepatitis (NAS 7/8) and advanced fibrosis (F3), attributed to metabolic dysfunction without evidence of alcohol recurrence. She decompensated with ascites and varices, leading to transplant re-enlistment at MELD-Na 29. Despite two years of intensive lifestyle modification, losing 17 kg, and recompensation, her follow-up elastography showed persistent steatosis (S3) and advanced fibrosis (F4). Subsequent allograft biopsy revealed progression to cirrhosis (F4) with ongoing steatohepatitis (NAS 3/8). Tirzepatide was initiated for the development of type 2 diabetes, attributed to steroids used for immunosuppression. After 2 years on tirzepatide, she lost 43.1 kg. Shockingly, her follow-up elastography demonstrated fibrosis regression with LSM 5.5 kPa (F1) and steatohepatitis resolution with CAP 204 dB/m (S0). Follow-up liver biopsy confirmed fibrosis regression to F2-F3 and steatohepatitis resolution (NAS 1/8). Conclusions: This case challenges the widely accepted dogma that liver MASH cirrhosis is irreversible. Using multiple liver fibrosis monitoring modalities, cirrhosis reversal was demonstrated and attributed to mechanisms of GLP-1/GIP RA therapy. This study suggests that GLP-1/GIP RA may be safe in cirrhosis and may result in fibrosis regression. Full article

The growing demand for low-frequency, broadband vibration and noise suppression technologies in next-generation mechanical equipment has become increasingly urgent. Effective negative mass locally resonant structures represent one of the most paradigmatic classes of acoustic metamaterials. Their unique elastic wave bandgaps enable efficient suppression of low-frequency vibrations, while inherent nonlinear effects provide significant potential for the design and tunability of these bandgaps. To achieve ultra-low-frequency and ultra-broadband vibration attenuation, this study employs Duffing oscillators exhibiting negative-stiffness characteristics as structural elements, establishing a bistable nonlinear acoustic-metamaterial mechanical model. Subsequently, based on the effective negative mass local resonance theory, the perturbation solution for the dispersion curves is derived using the perturbation method. Finally, the effects of mass ratio, stiffness ratio, and nonlinear term on the starting and cutoff frequencies of the bandgap are analyzed, and key geometric parameters influencing the design of ultra-low vibration reduction bandgaps are comprehensively investigated. Subsequently, the influence of external excitation amplitude and the nonlinear term on bandgap formation is analyzed using numerical computation methods. Finally, effective positive mass, negative mass, and zero-mass phenomena within distinct frequency ranges of the bandgap and passband are examined to validate the theoretically derived results. The findings demonstrate that, compared to a positive-stiffness system, the bandgap of the bistable nonlinear acoustic metamaterial incorporating negative-stiffness Duffing oscillators shifts to higher frequencies and widens by a factor of $\sqrt{2}$. The external excitation amplitude F changes the bandgap starting frequency and cutoff frequency. As F increases, the starting frequency rises while the cutoff frequency decreases, resulting in a narrowing of the bandgap width. Within the frequency range bounded by the bandgap starting frequency and cutoff frequency, the region between the resonance frequency and cutoff frequency corresponds to an effective negative mass state, whereas the region between the bandgap starting frequency and resonance frequency exhibits an effective positive mass state. Critically, the bandgap encompasses both effective positive mass and negative mass regions, wherein vibration propagation is suppressed. Concurrently, a zero-mass state emerges within this structure, with its frequency precisely coinciding with the bandgap cutoff frequency. This study provides a theoretical foundation and practical guidelines for designing nonlinear acoustic metamaterials targeting ultra-low-frequency and ultra-broadband vibration and noise mitigation. Full article

Train-induced vibrations negatively impact residents in nearby buildings and are increasingly recognized as a public health concern. To address this issue, both effective mitigation measures and simplified design procedures are essential. This study investigates the mitigation pattern induced by an array of stiff inclusions employing a modal dispersive analysis. However, applying this type of analysis to a half-space medium presents challenges. To overcome this limitation, a wave-scattering methodology is proposed. This approach enables the computation of the mitigation pattern in a specific direction and at a particular location. It also highlights the conditioning energy content, thereby identifying the key frequency target for attenuation. Full article

Vehicle suspension significantly influences the safety of cargo transportation. This study presents a 14-degree-of-freedom vehicle–cargo coupling model that explicitly incorporates the frequency-dependent stiffness of air springs. Systematic parametric investigations of air spring orifice resistance, loading mass, and cargo stiffness reveal the following: (a) Compared with leaf spring suspension, air suspension vehicles attenuated the first peak of acceleration power spectral density by over 50%, while slightly amplifying the second peak; (b) When replacing leaf spring suspension with air suspension, the upper-layer cargo exhibited significantly larger vibration reductions (14% vertical, 28% pitch) than the lower-layer cargo under identical cargo parameters. The roll angle should be controlled to prevent the cargo overturning when equipping air suspensions; (c) Under light loading conditions, the vertical vibration response in upper-layer cargo is amplified. This amplification can be effectively suppressed through two complementary approaches, i.e., employing low-stiffness cushion materials and reducing orifice resistance through tunable orifices, which collectively attenuate characteristic peaks in the frequency-domain response and comprehensively mitigate the vertical vibration of cargo. These findings provide guidance for designing transportation schemes for cargo in air suspension vehicles to enhance cargo safety. Full article

This study presents the development and performance evaluation of a rock asphalt-modified damping asphalt binder tailored for interlayer applications in photovoltaic pavement systems. A series of composite binders was formulated by incorporating Qingchuan rock asphalt, crumb rubber powder, and SBS polymer into base asphalt using an orthogonal design approach. The effects of different modifiers and their interactions were systematically assessed through conventional physical tests, DSR, BBR and damping ratio measurements. Furthermore, full-scale specimens (30 cm × 30 cm) were subjected to both single-pass and 24 h sustained loading tests to simulate real-world stress conditions. The results revealed that rock asphalt (RA) significantly enhanced the high-temperature stiffness and rutting resistance, while SBS improved ductility and low-temperature flexibility. Rubber powder (RP) notably increased the damping ratio, demonstrating superior energy dissipation potential. Among the nine formulations, the ternary blend of SBS, RA, and RP (denoted as L5) exhibited the most balanced and optimal performance, with G*/sinδ exceeding 5.0 kPa at 64 °C, a ductility of 132 cm, and damping ratios above 0.14. Load testing confirmed the material’s capacity for both instantaneous deformation resistance and delayed elastic recovery. These findings suggest that the L5 formulation is well suited for use in smart pavements where both mechanical durability and vibration attenuation are required. Full article

A healthy vasculature with well-regulated perfusion and pulsatility is essential for the brain. One vascular structure that has received little attention is the carotid siphon. The proximal portion of the siphon is stiff due to the narrow location in the skull base, whilst the distal portion is highly flexible. This flexible part in combination with the specific curves lead to lower pulsatility at the cost of energy deposition in the arterial wall. This deposited energy contributes to damage and calcification. Severe siphon calcification stiffens the distal part of the siphon, leading to less damping of the pulsatility. Increased blood flow pulsatility is a possible cause of stroke and cognitive disorders. In this review, based on comprehensive multimodality imaging, we first describe the anatomy and physiology of the carotid siphon. Subsequently, we review the in vivo imaging data, which indeed suggest that the siphon attenuates pulsatility. Finally, the data as available in the literature are shown to provide convincing evidence that severe siphon calcifications and the calcification pattern are linked to incident stroke and dementia. Interventional studies are required to test whether this association is causal and how an assessment of pulsatility and the siphon calcification pattern can improve personalized medicine, working to prevent and treat brain disease. Full article

Background: Transient elastography (TE), using Fibroscan^® and point shear wave elastography (pSWE), are two techniques used to estimate liver fibrosis. The aim of our study was to compare, for the first time, these two techniques in Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD), stratifying the analysis on the basis of the grades of steatosis. Methods: We recruited 85 consecutive MAFLD patients who underwent liver stiffness (LS) measurement performed by Fibroscan^® and pSWE on the same day. Severity of steatosis was estimated by Fibroscan^® and expressed as controlled attenuation parameter (CAP), ranging from S0 to S3. Spearman’s “r” coefficient was used to calculate the correlation and Bland–Altman graphs was used to evaluate the agreement. Results: In general, the correlation and agreement between Fibroscan^® and pSWE were substantial (r = 0.66, p < 0.001 and bias= −0.64 ± 2.48, respectively). When data were analyzed according to the grade of steatosis, an increasing significant correlation was observed going from S0 to S2 (r = 0.79, r = 0.81, and r = 0.85, respectively), whereas a low correlation and agreement were observed for S3 patients (r = 0.48, p = 0.003, bias= −0.95 ± 2.51). Conclusions: Fibroscan^® and pSWE are equivalent techniques to estimate liver fibrosis in patients with mild to moderate steatosis, while in presence of severe steatosis their agreement is low. Full article

Polyurethane foam is widely used as a primary filling material in car seats. While it provides good damping and energy absorption, the mechanical properties are complex but play a vital role in vibration attenuation and vehicle ride comfort. This study proposes a comprehensive experimental and analytical method to characterize the visco-hyperelastic properties of seat-grade polyurethane foam. Quasi-static and dynamic compression tests were conducted on foam blocks to obtain load–deflection curves and dynamic stiffness. A visco-hyperelastic material model was developed, where the hyperelastic response was derived via the hereditary integral and difference-stress method, and viscoelastic behavior was captured using a Prony series fitted to dynamic stiffness data. The model was validated using finite element simulations, showing good agreement with experimental results in both static and dynamic conditions. The proposed method enables accurate characterization of the visco-hyperelastic material properties of seat-grade polyurethane foam. Full article

Background: Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common chronic liver condition globally, strongly linked to obesity, insulin resistance, and type 2 diabetes (T2D). Tirzepatide (TZP), a dual GIP/GLP-1 receptor agonist, improves glycemic control and reduces body weight and the liver fat content in patients with obesity and T2D. However, its effect on liver-specific outcomes such as steatosis and fibrosis remains incompletely characterized. Low-energy ketogenic therapy (LEKT), a nutritional strategy characterized by carbohydrate restriction and nutritional ketosis, may enhance hepatic β-oxidation and reduce hepatic lipogenesis. To date, however, the combination of TZP and LEKT has not been studied in patients with metabolic dysfunction-associated steatotic liver disease (MASLD). This study aimed to compare the hepatic and metabolic effects of TZP combined with either LEKT or a conventional low-calorie diet (LCD) over a 12-week period. Methods: Sixty adult patients with MASLD undergoing TZP therapy were prospectively assigned to either an LEKT or a conventional LCD, with 30 participants per group. As primary endpoints, the controlled attenuation parameter (CAP, an index of hepatic steatosis) and liver stiffness measurement (LSM, an index of liver fibrosis) were assessed at the baseline and after 12 weeks using FibroScan^®. Secondary outcomes included changes in body mass index (BMI), glycated hemoglobin (HbA1c), and liver enzymes. Adherence to both diet and pharmacological treatment, as well as tolerability, were systematically monitored throughout the intervention period. Results: Both groups showed significant reductions in body weight (TZP + LEKT, p = 0.0289; TZP + LCD, p = 0.0278), with no significant intergroup difference (p = 0.665). CAP and LSM improved significantly in both groups, but reductions were greater in the TZP + LEKT group (CAP −12.5%, p < 0.001; LSM −22.7%, p < 0.001) versus LCD (CAP −6.7%, p = 0.014; LSM −9.2%, p = 0.022). Between-group differences were statistically significant for both CAP (p = 0.01) and LSM (p = 0.03). Conclusions: Based on these preliminary findings, we support the hypothesis that the combination of TZP and LEKT may be superior to TZP with an LCD in reducing hepatic steatosis and stiffness in individuals with obesity. Full article

Migrastatic strategies are considered as candidate therapeutic approaches to suppress cancer invasion into local surrounding tissues and metastatic spread. The F-actin cytoskeleton is responsible for key properties regulating (cancer) cell migration. The cortical F-actin network controls cell stiffness, which, in turn, determines cell migration strategies and efficiency. Moreover, the dynamic remodeling of F-actin networks mediating filopodia, lamellipodia, and F-actin stress fibers is crucial for cell migration. Here, we have used a conditional knockout approach to delete cofilin, an F-actin-binding protein that controls severing. We find that the deletion of cofilin prevents the migration of cancer cells from tumoroids into the surrounding extracellular matrix without affecting their viability. This identifies cofilin as a candidate target to suppress metastatic spread. Pharmacological inhibitors interfering with F-actin dynamics have been developed but their effects are pleiotropic, including severe toxicity, and their impact on 3D tumor cell migration has not been tested or separated from this toxicity. Using concentration ranges of a panel of inhibitors, we select cytochalasins based on the suppression of 2D migration at non-toxic concentrations. We then show that these attenuate the escape of tumor cells from tumoroids and their migration into the surrounding extracellular matrix without toxicity in 3D cultures. This effect is accompanied by suppression of cell stiffness at such non-toxic concentrations, as measured by acoustic force spectroscopy. These findings identify cytochalasins B and D as candidate migrastatic drugs to suppress metastatic spread. Full article

This study addresses the limitations of conventional evaluation methods caused by low porosity, strong heterogeneity, and complex pore structures in tight sandstone reservoirs. Through integrated rock physics experiments and multi-physical field modeling, the research systematically investigates the coupled response mechanisms between electrical and elastic parameters. The experimental approach includes pore structure characterization, quantitative mineral composition analysis, resistivity and polarizability measurements under various saturation conditions, P- and S-wave velocity testing, and scanning electron microscopy (SEM) imaging. The key findings show that increasing porosity leads to significant reductions in resistivity and elastic wave velocities, while also increasing surface conductivity. Specifically, clay minerals enhance surface conductivity through interfacial polarization effects and decrease rock stiffness, which exacerbates wave velocity attenuation. Furthermore, resistivity exhibits a nonlinear negative correlation with water saturation, with sharp increases at low saturation levels due to the disruption of conductive pathways. By integrating the Modified Generalized Effective Medium Theory of Induced Polarization (MGEMTIP) and Kuster–Toksöz models, this study establishes quantitative relationships between porosity, saturation, and electrical/elastic parameters, and constructs cross-plot templates that correlate elastic wave velocities with resistivity and surface conductivity. These analyses reveal that high-porosity, high-saturation zones are characterized by lower resistivity and wave velocities, coupled with significantly higher surface conductivity. The proposed methodology significantly improves the accuracy of reservoir evaluation and enhances fluid identification capabilities, providing a solid theoretical foundation for the efficient exploration and development of tight sandstone reservoirs. Full article

Background: Ginger contains gingerols, shagaols, paradols, gingerdiones, and terpenes, which have been shown to display anti-inflammatory properties and inhibit pain receptors. For this reason, ginger has been marketed as a natural analgesic. This study examined whether a specialized ginger extract obtained through supercritical CO₂ extraction and subsequent fermentation affects pain perception, functional capacity, and markers of inflammation. Methods: Thirty men and women (56.0 ± 9.0 years, 164.4 ± 14 cm, 86.5 ± 20.9 kg, 31.0 ± 7.5 kg/m²) with a history of mild to severe joint and muscle pain as well as inflammation participated in a placebo-controlled, randomized, parallel-arm study. Participants donated fasting blood, completed questionnaires, rated pain in the thighs to standardized pressure, and then completed squats/deep knee bends, while holding 30% of body mass, for 3 sets of 10 repetitions on days 0, 30, and 56 of supplementation. Participants repeated tests after 2 days of recovery following each testing session. Participants were matched by demographics and randomized to ingest 125 mg/d of a placebo or ginger (standardized to contain 10% total gingerols and no more than 3% total shogaols) for 58 days. Data were analyzed by a general linear model (GLM) analysis of variance with repeated measures, mean changes from the baseline with 95% confidence intervals, and chi-squared analysis. Results: There was evidence that ginger supplementation attenuated perceptions of muscle pain in the vastus medialis; improved ratings of pain, stiffness, and functional capacity; and affected several inflammatory markers (e.g., IL-6, INF-ϒ, TNF-α, and C-Reactive Protein concentrations), particularly following two days of recovery from resistance exercise. There was also evidence that ginger supplementation increased eosinophils and was associated with less frequent but not significantly different use of over-the-counter analgesics. Conclusions: Ginger supplementation (125 mg/d, providing 12.5 mg/d of gingerols) appears to have some favorable effects on perceptions of pain, functional capacity, and inflammatory markers in men and women experiencing mild to moderate muscle and joint pain. Registered clinical trial #ISRCTN74292348. Full article