Search Results (12)

Background and Objectives: Maternal dyslipidaemia and low-grade inflammation are recognised drivers of in utero vascular remodelling, yet composite dynamic markers that integrate lipid–glycaemic, inflammatory and endothelial signals have not been evaluated. We investigated whether eight-week trajectories in the triglyceride–glucose index (TyG), interleukin-6 (IL-6) and flow-mediated dilation (FMD) outperform single-timepoint lipids for predicting fetal aortic remodelling. Materials and Methods: In a prospective repeated-measures study, 90 singleton pregnancies were examined at 24–26 weeks (Visit-1) and 32–34 weeks (Visit-2). At each visit, we obtained fasting lipids, TyG index, hsCRP, IL-6, oxidative-stress markers (MDA, NOx), brachial flow-mediated dilation (FMD), carotid IMT and uterine-artery Doppler, together with advanced fetal ultrasonography (abdominal-aorta IMT, ventricular strain, Tei-index, fetal pulse-wave velocity). Mothers were grouped by k-means clustering of the visit-to-visit change (Δ) in TG, TyG, hsCRP, IL-6 and FMD into three Metabolic-Inflammatory Response Phenotypes (MIRP-1/2/3). Linear mixed-effects models and extreme-gradient-boosting quantified associations and predictive performance. Results: Mean gestational TG rose from 138.6 ± 14.1 mg/dL to 166.9 ± 15.2 mg/dL, TyG by 0.21 ± 0.07 units and FMD fell by 1.86 ± 0.45%. MIRP-3 (“Metabolic + Inflammatory”; n = 31) showed the largest change (Δ) Δ-hsCRP (+0.69 mg/L) and Δ-FMD (–2.8%) and displayed a fetal IMT increase of +0.17 ± 0.05 mm versus +0.07 ± 0.03 mm in MIRP-1 (p < 0.001). Mixed-effects modelling identified Δ-TyG (β = +0.054 mm per unit), Δ-IL-6 (β = +0.009 mm) and Δ-FMD (β = –0.007 mm per %) as independent determinants of fetal IMT progression. An XGBoost model incorporating these Δ-variables predicted high fetal IMT (≥90th percentile) with AUROC 0.88, outperforming logistic regression (AUROC 0.74). Conclusions: A short-term surge in maternal TyG, IL-6 and endothelial dysfunction delineates a high-risk phenotype that doubles fetal aortic wall thickening and impairs myocardial performance. Composite dynamic indices demonstrated superior predictive value compared with individual lipid markers. Full article

Postmenopausal women (PMW) may experience endothelial dysfunction associated with arginine (ARG) deficiency relative to asymmetric dimethylarginine (ADMA) caused by oxidative stress. Endothelial dysfunction contributes to increased blood pressure (BP) responsiveness to sympathoexcitation induced by the cold pressor test (CPT). We investigated the effects of citrulline alone (CIT) and combined with the antioxidant glutathione (CIT+GSH) on vascular function. Forty-four healthy PMW were randomized to CIT (6 g), CIT+GSH (2 g + 200 mg: Setria^®) or placebo (PL) for 4 weeks. Brachial artery flow-mediated dilation (FMD), aortic stiffness (pulse wave velocity, PWV), brachial and aortic BP reactivity to CPT, and serum fasting blood glucose (FBG), ARG, and ARG/ADMA ratio were measured. Baseline FBG was higher in CIT+GSH vs. PL. FMD increased after CIT+GSH vs. PL (p < 0.05). CIT and CIT+GSH increased ARG/ADMA (p < 0.05), but did not affect aortic PWV. CIT+GSH attenuated the brachial and aortic systolic BP and mean arterial pressure (MAP) responses to CPT vs. PL and CIT (p < 0.05). The improvements in FMD were related to baseline FMD (r = −0.39, p < 0.05) and aortic MAP response to CPT (r = −0.33, p < 0.05). This study showed that CIT+GSH improved FMD and attenuated systolic BP and MAP reactivity in PMW. Although CIT increased ARG/ADMA, it did not improve FMD in healthy PMW. Full article

To explore the stability analyses and control methods for surrounding rocks in deep hard rock shafts, this paper is based on field engineering geological surveys and laboratory rock mechanics tests and relies on the main shaft being constructed in the Shaling Gold Mine of China as the engineering background. The quality of the rock mass is evaluated by the Q system, rock mass rating (RMR) and geological strength index (GSI). The mechanical parameters of the surrounding rock mass of the shaft are calculated by using the generalized Hoek–Brown failure criterion, and the main support system is determined based on the rock mass classification system. Based on the finite element method, a two-dimensional plane strain model is constructed to analyze and evaluate the deformation and plastic region range of surrounding rocks for different support systems. On this basis, considering the dilatancy and plastic softening characteristics of hard rock masses, an analytical solution of the stress, strain and plastic region radius of hard rock around shafts in homogeneous media is proposed. Finally, the plastic region of the surrounding rock is measured by the P-wave velocity test method. The results show that after considering the dilatancy and plastic softening characteristics of the rock mass, the numerical simulation, theoretical analytical solution and measured results are basically consistent, and the proposed support system can effectively ensure the stability of the shaft. Full article

Ascending thoracic aortic aneurysm is a life-threatening disease, which is difficult to detect prior to the occurrence of a catastrophe. Epidemiology patterns of ascending thoracic aortic dilations/aneurysms remain understudied, whereas the risk assessment of it may be improved. The electronic databases PubMed/Medline 1966–2022, Web of Science 1975–2022, Scopus 1975–2022, and RSCI 1994–2022 were searched. The current guidelines recommend a purely aortic diameter-based assessment of the thoracic aortic aneurysm risk, but over 80% of the ascending aorta dissections occur at a size that is lower than the recommended threshold of 55 mm. Moreover, a 55 mm diameter criterion could exclude a vast majority (up to 99%) of the patients from preventive surgery. The authors review several visualization-based and alternative approaches which are proposed to better predict the risk of dissection in patients with borderline dilated thoracic aorta. The imaging-based assessments of the biomechanical aortic properties, the Young’s elastic modulus, the Windkessel function, compliance, distensibility, wall shear stress, pulse wave velocity, and some other parameters have been proposed to improve the risk assessment in patients with ascending thoracic aortic aneurysm. While the authors do not argue for shifting the diameter threshold to the left, they emphasize the need for more personalized solutions that integrate the imaging data with the patient’s genotypes and phenotypes in this heterogeneous pathology. Full article

Background: Cardiovascular health scores, such as Life’s Simple 7 from the American Heart Association, and the assessment of arterial properties are independently used to determine cardiovascular risk. However, evidence of their association remains scarce, especially in healthy, middle-aged to older populations. Methods: A healthy sample of the Swiss population aged 50–91 years as part of the COmPLETE cohort study was included. Carotid intima–media thickness (cIMT), carotid lumen diameter (cLD), carotid distensibility coefficient (DC), flow-mediated dilation (FMD), and brachial–ankle pulse wave velocity (baPWV) were used to determine arterial properties. The Life’s Simple 7 cardiovascular health score was calculated using seven categories (body-mass index, cholesterol, systolic blood pressure, hemoglobin A1c, smoking status, physical activity, and diet). In accordance with the American Heart Association, for each category, two points were given for an ideal health metric level, intermediate scores one point, and poor scores zero points. Intermediate and ideal health scores corresponded to a total of 5–9 and 10–14 points, respectively. Results: A total of 280 participants (50.7% male) were included. After adjusting for age and sex, an ideal health score was associated with lower cIMT (−0.038 mm, 95% CI: −0.069 mm–−0.007 mm, p = 0.017), lower cLD (−0.28 mm, 95% CI: −0.46 mm–−0.11 mm, p = 0.002), and lower baPWV (−0.05 m/s, 95% CI: −0.08 m/s–−0.02 m/s, p = 0.003). No differences were found for FMD and DC. Conclusions: Even in a healthy sample of middle-aged and older adults, individuals with an ideal cardiovascular health score showed more favorable biomarkers of vascular aging than those with an intermediate score. This stresses the relevance of promoting an optimal lifestyle, even among the healthy population. Full article

To investigate the influence of hydration on brittle deformation of oceanic crustal rocks, we conducted triaxial deformation experiments on gabbroic rocks with various degrees of hydration at a confining pressure of 20 MPa and room temperature, measuring elastic wave velocity. Hydrated olivine gabbros reached a maximum differential stress of 225–350 MPa, which was considerably less than those recorded for gabbros (~450 MPa), but comparable to those for serpentinized ultramafic rocks (250–300 MPa). Elastic wave velocities of hydrated olivine gabbros did not show a marked decrease even prior to failure. This indicated that the deformation of hydrated olivine gabbro is not associated with the opening of the stress-induced cracks that are responsible for dilatancy. Microstructural observations of the samples recovered after deformation showed crack damage to be highly localized to fault zones with no trace of stress-induced crack opening, consistent with the absence of dilatancy. These data suggest that strain localization of hydrated olivine gabbro can be caused by the development of shear cracks in hydrous minerals such as serpentine and chlorite, even when they are present in only small amounts. Our results suggest that the brittle behavior of the oceanic crust may considerably change due to limited hydration. Full article

This study uses a dynamic caustic technique to study the crack propagation in a medium containing an unfilled joint under blasting. The results show that for the medium containing a vertical unfilled joint, the reflected dilatational wave from the joint tends to suppress both the $K_{\mathrm{I}}^d$ and the velocity of the opposite propagating crack. However, for the medium containing an oblique joint, the reflected wave from the joint increases $K_{\mathrm{II}}^d$ , and induces the opposite propagating crack deflect from its original path. Compared with the medium with a vertical joint, the wing cracks are more easy to initiate at the oblique joint where a significant stress concentration is formed under the diffraction of the blast wave. Combined with numerical results, it is found that the wing crack deflects in the clockwise direction when the shear stress was negative, and it turns to counterclockwise when the shear stress was positive. Full article

The objective of this study was to specify, parameterize, and evaluate an acoustic-based inferential framework for estimating commercially-relevant wood attributes within standing jack pine (Pinus banksiana Lamb) trees. The analytical framework consisted of a suite of models for predicting the dynamic modulus of elasticity (m_e), microfibril angle (m_a), oven-dried wood density (w_d), tracheid wall thickness (w_t), radial and tangential tracheid diameters (d_r and d_t, respectively), fibre coarseness (c_o), and specific surface area (s_a), from dilatational stress wave velocity (v_d). Data acquisition consisted of (1) in-forest collection of acoustic velocity measurements on 61 sample trees situated within 10 variable-sized plots that were established in four mature jack pine stands situated in boreal Canada followed by the removal of breast-height cross-sectional disk samples, and (2) given (1), in-laboratory extraction of radial-based transverse xylem samples from the 61 disks and subsequent attribute determination via Silviscan-3. Statistically, attribute-specific acoustic prediction models were specified, parameterized, and, subsequently, evaluated on their goodness-of-fit, lack-of-fit, and predictive ability. The results indicated that significant (p ≤ 0.05) and unbiased relationships could be established for all attributes but d_t. The models explained 71%, 66%, 61%, 42%, 30%, 19%, and 13% of the variation in m_e, w_t, s_a, c_o, w_d, m_a, and d_r, respectively. Simulated model performance when deploying an acoustic-based wood density estimate indicated that the expected magnitude of the error arising from predicting d_t, c_o, s_a, w_t, m_e, and m_a prediction would be in the order of ±8%, ±12%, ±12%, ±13%, ±20%, and ±39% of their true values, respectively. Assessment of the utility of predicting the prerequisite w_d estimate using micro-drill resistance measures revealed that the amplitude-based w_d estimate was inconsequentially more precise than that obtained from v_d (≈ <2%). A discourse regarding the potential utility and limitations of the acoustic-based computational suite for forecasting jack pine end-product potential was also articulated. Full article

Background: Poor glycaemic control affects myocardial function. We investigated changes in endothelial function and left ventricular (LV) myocardial deformation in poorly controlled type 2 diabetics before and after glycaemic control intensification. Methods: In 100 poorly-controlled diabetic patients (age: 51 ± 12 years), we measured at baseline and at 12 months after intensified glycaemic control: (a) Pulse wave velocity (PWV, Complior); (b) flow-mediated dilatation (FMD, %) of the brachial artery; (c) perfused boundary region (PBR) of the sublingual arterial micro-vessels (side-view dark-field imaging, Glycocheck); (d) LV global longitudinal strain (GLS), peak twisting (pTw), peak twisting velocity (pTwVel), and peak untwisting velocity (pUtwVel) using speckle tracking echocardiography, where the ratio of PWV/GLS was used as a marker of ventricular-arterial interaction; and (e) Malondialdehyde (MDA) and protein carbonyls (PCs) plasma levels. Results: Intensified 12-month antidiabetic treatment reduced HbA1c (8.9 ± 1.8% (74 ± 24 mmol/mol) versus 7.1 ± 1.2% (54 ± 14 mmol/mol), p = 0.001), PWV (12 ± 3 versus 10.8 ± 2 m/s), PBR (2.12 ± 0.3 versus 1.98 ± 0.2 μm), MDA, and PCs; meanwhile, the treatment improved GLS (−15.2 versus −16.9%), PWV/GLS, and FMD% (p < 0.05). By multi-variate analysis, incretin-based agents were associated with improved PWV (p = 0.029), GLS (p = 0.037), PBR (p = 0.047), and FMD% (p = 0.034), in addition to a reduction of HbA1c. The patients with a final HbA1c ≤ 7% (≤ 53 mmol/mol) had greater reduction in PWV, PBR, and markers of oxidative stress, with a parallel increase in FMD and GLS, compared to those who had HbA1c > 7% (> 53 mmol/mol). Conclusions: Intensified glycaemic control, in addition to incretin-based treatment, improves arterial stiffness, endothelial glycocalyx, and myocardial deformation in type 2 diabetes after one year of treatment. Full article

Ultrasonic waves, which constitute an active testing method, and acoustic emissions (AE), which can be applied as passive testing technology, can reveal rock damage processes in different ways. However, few studies so far have simultaneously adopted both, owing to the limitations of the experimental apparatus. However, the simultaneous use of both methods can improve the experimental efficiency and help to understand the rock damage evolution more comprehensively. In this study, concurrent experiments of ultrasonic waves and AE activities were carried out on rock salt under uniaxial compression, and the deformation characteristics were measured. The fracture process was divided into four stages with individual characteristics: the elastic compression stage, brittle-ductile transition with crack initiation, brittle-ductile transition with damage initiation, and plastic deformation and strain hardening stage. The ultrasonic wave velocity, crack density, ultrasonic wave amplitude, and attenuation coefficient were obtained to evaluate the damage process. The ultrasonic wave amplitude and the attenuation coefficient were recommended as forecast indicators, owing to their sensitivity and operability of measurement. The confining pressure had an inhibitory effect on crack expansion and on the AE activity, and the damage ultimate stress was defined and determined according to the AE activity and energy release characteristics. Four critical strengths of the crack initiation threshold stress, dilatancy boundary stress, short-term strength, and damage ultimate stress of rock salt were determined and then discussed. These results are valuable in evaluating rock damage and guiding the operation of underground salt caverns. Full article

Ultrasonic waves and acoustic emissions (AE) are important technologies to reveal rock damage. However, few studies have simultaneously monitored both types of data in the same experiment because of limitations on the experimental apparatus. In this study, an integrated ultrasonic wave and AE testing device was developed to investigate the deformation characteristics and damage development of salt rock. Fracture experiments under uniaxial compression were carried out on three samples from the Jintan Salt Mine, Jiangsu Province, China. The deformation process can be divided into five stages. In the compression fissure and linear deformation stages, P- and S-waves rose slightly to stability, and acoustic emission activity was weak (0.04% and 2.66%, respectively). Subsequently, S-wave velocity slowly declined and AE events become more active, with about 13.8% of the total in the stabilized-growth cracks stage. When the salt rock entered the accelerated-growth cracks stage, AE events increased to 75.27%; with features of an earthquake swarm, the velocities of P- and S-waves began to fall significantly. After the peak stress, salt rock produced only a small number of AE events. The beginning stress of rock damage and dilatancy were about 42–50% and 62–67% of the uniaxial compressive strength, respectively. The ultrasonic wave velocity ratio, Ib-value, and r-value effectively predicted rock failure, but the r-value was superior owing to its sensitivity and ease of measurement. Full article

When moving discontinuities in solids need to be simulated, standard finite element (FE) procedures usually attain low accuracy because of spurious oscillations appearing behind the discontinuity fronts. To assure an accurate tracking of traveling stress waves in heterogeneous media, we propose here a flux-corrected transport (FCT) technique for structured as well as unstructured space discretizations. The FCT technique consists of post-processing the FE velocity field via diffusive/antidiffusive fluxes, which rely upon an algorithmic length-scale parameter. To study the behavior of heterogeneous bodies featuring compliant interphases of any shape, a general scheme for computing diffusive/antidiffusive fluxes close to phase boundaries is proposed too. The performance of the new FE-FCT method is assessed through one-dimensional and two-dimensional simulations of dilatational stress waves propagating along homogeneous and composite rods. Full article