Abstract Longitudinal uneven deformation caused by subgrade frost heave in seasonally frozen regions seriously threatens the operational safety and structural performance of high-speed railways. To investigate the dynamic impact of frost heave on the vehicle–track system, this study develops a coupled dynamic model based on vehicle–track interaction theory, integrating a CRH3 high-speed train with a CRTS I slab track. Frost heave amplitude and wavelength are defined as key control parameters. Numerical simulations are conducted to analyze vehicle stability and track structural responses under various frost-heave conditions. A multi-indicator evaluation approach is adopted, incorporating indicators such as wheel–rail force, derailment coefficient, rail acceleration, vehicle body acceleration, rail displacement, and wheel-load reduction ratio. Results indicate that increasing frost heave amplitude significantly intensifies wheel–rail dynamic interactions and track responses. When the amplitude exceeds 15 mm, the vertical rail displacement approaches or exceeds the recommended limit under the simulated conditions. A sensitive relationship is observed between frost heave wavelength and vehicle bogie wheelbase, with amplified dynamic responses observed near a wavelength of 20 m, where both vehicle vibration and track response peak. Moreover, train speed interacts with frost-heave parameters, and high-speed operation is associated with increased dynamic responses. These findings provide insights into the dynamic response characteristics of the vehicle--track system under frost heave conditions, offering a reference for safety assessment and maintenance strategies in cold-region high-speed railways.

Myocardial deformation recovery after M-TEER: Associations with 1-year clinical improvement.

Gaucher disease type 1 (GD1) is a rare, multisystemic lysosomal storage disorder in which cardiac involvement may remain clinically silent for years. Conventional echocardiographic indices often fail to detect early myocardial dysfunction. Speckle-tracking echocardiography (STE) allows the assessment of subclinical myocardial deformation and may provide incremental prognostic information. This study aimed to investigate the association between ventricular deformation parameters and worsening disease severity, assessed by the Disease Severity Scoring System (DS3), using a bootstrap-based statistical approach suitable for rare disease cohorts. Patients with GD1 underwent comprehensive transthoracic echocardiography, including STE-derived left ventricular global longitudinal strain (LV GLS) and right ventricular (RV) longitudinal strain analysis. Conventional systolic parameters were also recorded. Multivariable regression analysis was performed to identify independent predictors of worsening DS3 score. To enhance statistical robustness in this small cohort, bootstrapping with 10000 resamples was applied. Conventional systolic parameters, including left ventricular ejection fraction, tricuspid annular plane systolic excursion, peak systolic velocity of the tricuspid annulus, and RV fractional area change, were within normal ranges and did not differ significantly between GD1 patients and healthy controls (p = NS for all). In contrast, STE revealed significantly reduced longitudinal deformation in GD1 patients for both the LV (-20.1% ± 1.3vs. -22.4% ± 2.6, p = 0.029) and RV (-22.2% ± 2.3vs. -25.4% ± 3.7, p = 0.036). In the bootstrap-adjusted multivariable model, LV GLS was the only independent predictor of worsening DS3 score (B = 26.024, p < 0.001; 95% CI: 2.669-47.893). Myocardial deformation abnormalities precede detectable changes in conventional systolic indices in GD1. LV GLS is a robust and independent predictor of increasing disease severity. STE may therefore represent a valuable tool for early detection of subclinical cardiac involvement and risk stratification in this rare disease population.

Analysis of Longitudinal Deformation of Existing Tunnel Caused by New Shield Tunneling Based on Timoshenko-Kerr Model

Longitudinal deformation response of existing tunnel to upper deep excavation based on LAAF-PINN

Superior longitudinal strength of auxetic stents: A comparative numerical study.

Background: Left ventricular global longitudinal strain (GLS) measured by speckle-tracking echocardiography (STE) has become a key marker of myocardial systolic function, yet normal reference values remain heterogeneous, and the magnitude of physiological sex differences is not fully defined. We performed a systematic review and meta-analysis to establish pooled GLS reference estimates in healthy individuals, quantify sex-related differences, and contextualize deformation findings relative to conventional systolic function. Methods: A systematic search of PubMed, Scopus, and EMBASE identified observational studies reporting GLS in healthy adults assessed by two-dimensional or three-dimensional STE. Random-effects meta-analysis using standardized mean differences (SMD) compared GLS between women and men. Descriptive pooled reference values were derived using weighted median and interquartile range (IQR) reconstruction from study-level distributions. Meta-regression analyses explored demographic, clinical, and methodological sources of heterogeneity. A complementary analysis evaluated sex-related differences in left ventricular ejection fraction (LVEF) within the same populations. Results: Thirty-two studies, including 19,157 healthy individuals, were analyzed. The pooled population had a weighted median age of 47.5 years and 53% female participants. Overall, GLS demonstrated a weighted median of 20.3% (IQR 17.8-22.5). Women showed higher GLS values than men (20.8% [18.4-23.1] vs. 19.4% [17.0-21.6]). Meta-analysis of 28 studies confirmed significantly greater GLS in females (SMD 0.487, 95% CI 0.409-0.565; p < 0.001), with consistent findings across imaging modalities and no subgroup interaction. Between-study heterogeneity was substantial (I2 = 82.7%), although effect direction was uniform. Meta-regression analyses identified no significant moderators, and sensitivity analyses confirmed stable estimates without publication bias. Segmental analysis demonstrated a physiological base-to-apex strain gradient. In contrast, LVEF was largely comparable between sexes, with no clinically meaningful difference (SMD 0.257, 95% CI 0.186-0.327; p < 0.001), indicating preserved global systolic performance despite differences in myocardial deformation. Conclusions: GLS demonstrates a consistent physiological range in healthy populations, with women exhibiting higher longitudinal deformation than men, independent of the imaging modality. These findings support the adoption of sex-specific GLS reference values and highlight the complementary roles of deformation and volumetric indices in improving the interpretation of myocardial function and reducing misclassification in clinical practice.

Association between BMI and longitudinal deformation of the left atrium in older adults

Rack railway represents a distinctive solution for mountain rail transportation due to its superior adaptability to steep gradients, but the gear-rack traction mechanism introduces complex longitudinal forces that may challenge track stability. This study employs a coupled Multi-Flexible-Body Dynamics-Discrete Element Method (MFBD-DEM) framework to develop a rack train-ballasted track interaction model. The proposed model enables closed-loop force-displacement transmission among the train, track, and discrete ballast bed, and its reliability is validated through field dynamic tests. Based on this model, both mesoscopic ballast behaviour and macroscopic track responses were examined under straight-line operation on a 360‰ gradient. The results reveal that, compared with the conventional wheel-rail driving method, the gear-rack driven system promotes enhanced longitudinal migration of ballast particles. As train speed increases, the dominant particle velocity direction expands from 255°–270° to 210°–270°, indicating a more pronounced downslope flow tendency. Furthermore, the sleepers experience approximately 0.1–0.2 mm permanent longitudinal displacement and 0.3°–0.5° of cumulative rotation during operation, suggesting the risk of irreversible longitudinal deformation within the track structure.

The possibility of obtaining information on the increase in disturbance of geomaterials caused by the intensification of deformation processes occurring in them is investigated by variations in the intensity of concomitant IR radiation. The results of experiments on the registration of thermal radiation from the surface of rock salt samples under conditions of uniaxial compression close to the limit conditions of periodic loading are presented. The qualitative identity of the recordings of mechanical parameters and variations of IR radiation characterizing changes in the stress–strain state of the tested rock samples is shown. It has been established that the recorded changes in the angle of inclination of the dependences of the intensity of thermal radiation from the surface of rock salt samples on longitudinal deformation in areas of load growth under high–amplitude periodic exposure are similar to changes in the values of the deformation modulus E, calculated in the same way in the corresponding sections of the stress-strain diagrams. It is concluded that it is possible to use the results of non-contact thermoradiometric measurements, namely, data on changes in the angle of inclination of these curves as an indicator of the degree of disturbance of geomaterials.

Inflammatory myocardial involvement has been reported in canine leishmaniosis (CanL); however, studies evaluating the degree of myocardial dysfunction in affected dogs are limited. This prospective study aimed to investigate myocardial involvement in dogs with CanL using conventional and speckle-tracking echocardiography (STE), focusing on the assessment of left ventricular systolic function and myocardial strain. Symptomatic, initially untreated dogs with a diagnosis of leishmaniosis and free from other vector-borne diseases or underlying heart diseases were enrolled (Leish group). Healthy dogs matched for age, body weight, breed, and sex were selected for the control group (C group). At the time of inclusion (T0) and at each follow-up, laboratory tests as well as conventional echocardiographic examination and STE were performed. For strain analysis, apical longitudinal long-axis 4-chamber, 3-chamber, and 2-chamber views were used (2C, 3C, 4C, respectively) to obtain the average global longitudinal strain (GLSAV), which is recognised to have the maximum reliability as an indicator of left ventricular dysfunction in humans. The software obtains GLSAV by averaging the longitudinal strain values from all left-ventricular segments derived from the multiple apical views. After enrolment, dogs were treated with a combination of meglumine and allopurinol and were monitored for six months. Clinical-pathological and echocardiographic data were collected at follow-up at 1, 3, and 6 months after the start of treatment (T1, T2, T3) and compared between the two study groups using appropriate statistical tests. Sixteen dogs composed the C group and nine dogs the Leish group. At T0, none of these dogs had abnormalities in cardiac auscultation, plasma cardiac troponin concentration was within the reference range, and standard echocardiographic examination excluded underlying cardiac diseases. The comparison between C and Leish groups did not show a statistically significant difference in any of the strain parameters analysed (GLSAV, GLS4C, GLS3C, GLS2C). Moreover, strain values in the Leish group did not change significantly over time. In conclusion, in this preliminary study on a limited population of dogs with leishmaniosis, both conventional echocardiography and STE failed to reveal clear changes suggestive of left ventricular systolic dysfunction secondary to possible myocarditis or as a consequence of the systemic disease in dogs with active leishmaniosis. However, further STE studies in larger cohorts of dogs with leishmaniosis are needed to confirm and expand our findings.

Longitudinal Stent Deformation Leading to Very Late Stent Thrombosis After De-Escalation of Dual Antiplatelet Therapy.

Wild-type transthyretin cardiac amyloidosis (ATTRwt-CA) is now increasingly identified as a cause of heart failure in older adults. This study aimed to clarify the morphological and functional alterations of the left ventricle (LV) that define the early stage of this condition. We prospectively evaluated 81 patients diagnosed with wild-type ATTR (ATTRwt) amyloidosis (mean age 77 ± 6 years; 88% male), categorized into three groups based on myocardial uptake on radioactive pyrophosphate scintigraphy and histological confirmation: (i) carpal ATTR without cardiac involvement (Group 1, n = 13), (ii) asymptomatic cardiac involvement (Group 2, n = 10) and (iii) overt heart failure (Group 3, n = 58). Compared with Group 3, Group 1 showed higher absolute global longitudinal strain (GLS) (median 19.0 [13.2-23.8]%, P < .001), a lower apical-sparing ratio (median 0.66 [0.55-1.04], P < .001) and lower brain natriuretic peptide (BNP) (median 13.5 [6-49] pg/mL, P < .001) and troponin-T concentrations (0.012 [0.006-0.022] ng/mL, P < .001), while the estimated glomerular filtration rate remained preserved (64 ± 9 mL/mL/1.73 m², P = .022). Segmental longitudinal strain (LS) differentiated Group 1 from Group 2, with basal inferoseptal LS significantly lower in patients with elevated troponin-T (> 0.014 ng/mL) than in those with lower values (13.9 ± 5.6% vs. 7.4 ± 1.8%, P = .046) in Group 1. A basal inferoseptal LS cutoff of 9.1% identified high troponin-T with an area under the curve (AUC) of 0.833 (P = .005), outperforming GLS (AUC 0.306, P = .217), BNP (AUC 0.667, P = .292), and LV ejection fraction (AUC 0.556, P = .743). Basal inferoseptal LS impairment may indicate early cardiac involvement in individuals with carpal tunnel syndrome carrying ATTRwt deposits.

Background . A comprehensive, integrated assessment of serum biomarkers and modern noninvasive imaging methods reflecting myocardial and vascular remodeling processes can facilitate the early diagnosis of heart failure in patients with arterial hypertension (HTN) and coronary artery disease (CAD) living in the Far North. Objective . To study the characteristics of laboratory and instrumental parameters reflecting cardiac and vascular remodeling processes in patients with HTN and CAD living in the Far North and temperate climate zones. Design and methods . In a comparative cohort study, patients with HTN and CHD (n = 99) were divided into two groups based on their place of permanent residence. Group 1 (n = 41) resided in a temperate climate zone, while Group 2 (n = 58) resided in the Far North. Inclusion criterion for the study was left ventricular (LV) ejection fraction &gt; 50 %. All participants underwent assessment of immune inflammation and remodeling biomarkers and transthoracic echocardiography to measure left heart deformation parameters: global LV longitudinal strain and left atrial (LA) reservoir phase strain using spot tracking. Noninvasive hemodynamic and tissue fluid assessment was performed using regional bioimpedance cardiography. Results . Patients in Group 2 had higher levels of matrix metalloproteinases 2 and 9 (MMP-2, MMP-9), and growth differentiation factor 15 (GDF-15), and a trend toward increased malondialdehyde concentrations. Both groups showed initial signs of impaired diastolic function of the LA, manifested by increased lateral and septal mitral annular velocities and elevated total peripheral resistance. Patients in Group 2 had more pronounced impairment of global LV longitudinal strain. A relationship was found between LV filling pressure (E/eʼ) and arterial compliance in both groups. In Group 2, with an increased number of segments (≥ 3) with impaired LV deformation, decreased LV systolic function and arterial compliance, as well as increased MMP-9 and homocysteine levels, were observed. Conclusions . Myocardial and vascular remodeling is more pronounced in patients with HTN and CAD in the Far North compared to those living in temperate climates. This is determined by impaired LV longitudinal deformation, higher levels of serum biomarkers of myocardial remodeling and immune inflammation, and an association between arterial compliance and LA strain.

Physics-informed neural network for predicting longitudinal deformation in super-large-diameter shallow-buried shield tunnel during construction

Abstract As electronics continue to shrink in size, the demand for miniaturized heat pipes used in cooling applications has surged. This trend imposes stringent requirements on the shell material, particularly oxygen-free copper tubes, which must exhibit excellent bendability without significant wrinkling. Consequently, precise control over the microstructure of the oxygen-free copper tubes has become crucial. In this study, the optimal processing technology for rare earth microalloyed oxygen-free copper tubes was investigated by characterizing and comparing the microstructures of rare earth microalloyed tubes and corresponding heat pipes produced using different annealing processes. The focus is on the proportion and distribution of different textures and twins within the microstructure, and their correlation with the mechanical properties of the heat pipes. The findings reveal that inline annealing enhances the tensile strength of both rare earth microalloyed oxygen-free copper tube and rare earth microalloyed heat pipe. However, this process also promotes the formation of twins while suppressing the growth of the Goss texture, leading to reduced microstructural uniformity. This non-uniformity makes the tube more prone to localized stress concentration during bending, resulting in significant wrinkling. Conversely, lowering the degree of annealing of rare earth microalloyed oxygen-free copper tube facilitates the development of the Goss texture, which endows the final rare earth microalloyed heat pipe with superior longitudinal deformation capability. Experimental results demonstrate that rare earth microalloyed oxygen-free copper heat pipes treated with the 400°C/25min annealing process demonstrate optimal comprehensive performance: their microstructure exhibits the highest proportion of Goss texture, the best organizational uniformity, while maintaining a relatively ideal tensile strength range. Industrial production validation data shows that this process achieves a product qualification rate as high as 97.2%, conclusively proving that the 400°C/25min annealing parameters constitute the optimal process window for manufacturing oxygen-free copper heat pipes.

The choice of materials for mechanical or civil engineering applications depends on both structural and mechanical characteristics. The latter is more important as the material is intended to support loads that force it to undergo both transverse and longitudinal deformations. The aim of this study is to analyze the three-point bending behavior in the specimen condition of virgin or recycled polyethylene/eucalyptus fiber composites. However, two types of composites were formulated, and bending tests were carried out to determine the deformation characteristics following an applied stress. The elastic modulus E, which characterizes the stiffness or flexibility of the material, was discussed and the results compared between virgin and recycled LDPE matrix composites. Virgin low-density polyethylene (LDPE V ) matrix composites showed better flexural strength than recycled matrix (LDPE R ) composites. On the other hand, Charpy impact strength showed that recycled low-density polyethylene (LDPE R ) matrix composites had better impact strength than virgin low-density polyethylene (LDPE V ) matrix composites.

We study the behaviour of a thin fluid filament (a rivulet) flowing in an air-filled Hele-Shaw cell. Transverse and longitudinal deformations can propagate on this rivulet, although both are linearly attenuated in the parameter range we use. On this seemingly simple system, we impose an external acoustic forcing, homogeneous in space and harmonic in time. When the forcing amplitude exceeds a given threshold, the rivulet responds nonlinearly, adopting a peculiar pattern. We investigate the dance’ of the rivulet both experimentally using spatiotemporal measurements, and theoretically using a model based on depth-averaged Navier–Stokes equations. The instability is due to a three-wave resonant interaction between waves along the rivulet, the resonance condition fixing the pattern wavelength. Although the forcing is additive, the amplification of transverse and longitudinal waves is effectively parametric, being mediated by the linear response of the system to the homogeneous forcing. Our model successfully explains the mode selection and phase-locking between the waves, it notably allows us to predict the frequency dependence of the instability threshold. The dominant spatiotemporal features of the generated pattern are understood through a multiple-scale analysis.

Abstract Introduction: Flatfoot (pes planus) occurs when the medial longitudinal arch flattens, causing discomfort and potential deformities in the feet, knees and ankles. The study aimed to determine the prevalence of flatfoot and its associated factors amongst patients attending a preventive health and screening outpatient department at the tertiary care hospital in Delhi. Methods: This cross-sectional study was conducted over 3 months at a tertiary care hospital, enrolling patients aged 18 years and above through the systematic random sampling. Data collection included demographic information, physical activity levels, body mass index and medical history. A three-dimensional foot scanner categorised participants into five-foot structure groups: high arch, normal arch, mild flatfoot, moderate flatfoot and severe flatfoot. The accuracy of the scanner was validated through clinical examination. Multivariate logistic regression was used to analyse the association between flatfoot and various factors. Results: The prevalence of flatfoot was 33% (95% confidence interval: 27.9%–38.4%) in either foot, with 25.6% in the right foot and 26.5% in the left foot. Gender was significantly associated with flatfoot, with women nearly twice as likely to have flatfoot compared to men (adjusted odds ratio [AOR] = 1.9, P = 0.01). Physical activity had a protective effect; those engaging in more than 150 min of physical activity per week had a lower prevalence of flatfoot (AOR = 0.04, P = 0.01). Conclusion: The study revealed a flatfoot prevalence of 33% in the population, with significant associations observed between gender and physical activity levels. Given these findings, routine screening for flatfoot is recommended. Early detection, coupled with interventions like targeted exercises or the use of custom insoles, can help mitigate long-term complications and improve the quality of life for affected individuals.

Abstract Introduction Understanding the pathogenetic mechanisms of chronic heart failure (CHF) development, particularly the interrelation between right and left ventricular function, allows for the creation of more effective diagnostic strategies aimed at preventing disease progression. Purpose To assess the role of right ventricular deformation parameters in the progression of chronic heart failure in patients with ischemic heart disease. Materials and Methods The study included 87 patients hospitalized at our Medical Center of Cardiology with ischemic heart disease and chronic heart failure of functional class II, III, and IV, representing various CHF phenotypes. The following right ventricular systolic deformation parameters were analyzed: RVFWLS — longitudinal strain of the right ventricular free wall; RV4CLS — four-chamber longitudinal strain of the right ventricle. Results In the group with reduced ejection fraction (EF &amp;lt; 40%), deformation parameters were the lowest: RVFWLS was 14.0 ± 4.1% and RV4CLS was 10.5 ± 3.1%. In the group with preserved ejection fraction (EF ≥ 50%), deformation values were higher: RVFWLS was 21.3 ± 4.0% and RV4CLS was 18.1 ± 3.2%. In the group with intermediate ejection fraction (EF 40–49%), deformation values were between these two groups: RVFWLS was 19.9 ± 2.8% and RV4CLS was 16.0 ± 2.7%. These intergroup differences were statistically significant, with a marked difference in the four-chamber longitudinal strain of the right ventricle (F=38.625, P=0.001 and F=65.366, P=0.001). Conclusion As the right ventricular ejection fraction decreases (transitioning from preserved to reduced EF), there is a significant deterioration in the longitudinal systolic deformation of the right ventricle, confirmed by statistically significant differences observed.