Search Results (89)

Mannitol dehydration is routinely used to prevent and treat cerebral damage after total aortic arch replacement (TAAR), but existing neuroimaging technologies cannot achieve bedside real-time quantitative assessment of its impact on cerebral perfusion in different patients. This study applied dynamic cerebral perfusion electrical impedance tomography (DCP-EIT), a non-invasive neuroimaging technique, for bedside cerebral perfusion monitoring in TAAR patients during dehydration. Seventeen patients with normal neurological function and nineteen with neurological dysfunction (ND) were enrolled. The variation patterns and differences in perfusion impedance, images, and the relative ratios (RY) of mean perfusion velocity (MV), height of systolic wave (Hs), inflow volume velocity (IV), and angle between the ascending branch and baseline (A_ab) were analyzed. Results showed DCP-EIT could visualize cerebral perfusion changes, with detected poorly perfused regions showing good consistency with ischemic areas identified by computed tomography (CT). RY of normal patients fluctuated around 0.97–1.04, with no significant difference from baseline. RY of ND patients peaked at 14–20 min after dehydration and remained higher than baseline even at 100 min (p < 0.001). DCP-EIT holds potential to optimize individualized cerebral protection strategies for other cerebral damage scenarios and neurocritical care. Full article

Background and Objectives: What led to the development of elastography was the emerging need for a method that could objectively and accurately assess the stiffness of internal structures. As a result, a distinction between normal from pathological tissues becomes possible. Objective: To evaluate non-invasive elastographic techniques, point shear wave elastography (pSWE) and two-dimensional shear wave elastography (2D-SWE), as methods for differentiating simple liver cysts from liver hemangiomas. Materials and Methods—a total of 63 patients—32 with simple liver cysts and 31 with liver hemangiomas were analyzed. The purpose was to determine the values of the average trend (arithmetic mean or median according to the data distribution) as well as the reference intervals of SWV for both methods in the above-mentioned patients. Final diagnoses were confirmed by contrast-enhanced computed tomography (CECT). Results: The pSWE SWV values (median) for simple hepatic cysts showed an average trend of 1.14 m/s, with an upper limit of 3.33 m/s and a lower limit of 0.35 m/s. For 2D-SWE, the average trend for simple hepatic cysts was 1.00 m/s, with an upper limit of 1.54 m/s and a lower limit of 0.65 m/s. For liver hemangiomas, the average trend in pSWE was 1.36 m/s, with an upper limit of 3.22 m/s and a lower limit of 0.57 m/s. For 2D-SWE, the average trend was 1.34 m/s, with an upper limit of 2.27 m/s and a lower limit of 0.80 m/s. Findings in our work mainly serve as reference values. Conclusions: The accurate diagnosis of liver diseases is of paramount importance when it comes to the approach and treatment of individual benign liver lesions. Early diagnosis of focal liver lesions remains a challenging task. Full article

Clarifying the differential effects of temperature gradient and temperature change rate on the evolution of rock fractures and damage mechanism under thermal shock is of great significance for the development and utilization of deep geothermal resources. In this study, granite samples at different temperatures (20 °C, 150 °C, 300 °C, 450 °C, 600 °C, and 750 °C) were subjected to rapid cooling treatment with liquid nitrogen. After the thermal treatment, a series of tests were conducted on the granite, including wave velocity test, uniaxial compression experiment, computed tomography scanning, and scanning electron microscopy test, to explore the influence of thermal shock on the physical and mechanical parameters as well as the meso-structural damage of granite. The results show that with the increase in heat treatment temperature, the P-wave velocity, compressive strength, and elastic modulus of granite gradually decrease, while the peak strain gradually increases. Additionally, the failure mode of granite gradually transitions from brittle failure to ductile failure. Through CT scanning experiments, the spatial distribution characteristics of the pore–fracture structure of granite under the influence of different temperature gradients and temperature change rates were obtained, which can directly reflect the damage degree of the rock structure. When the heat treatment temperature is 450 °C or lower, the number of thermally induced cracks in the scanned sections of granite is relatively small, and the connectivity of the cracks is poor. When the temperature exceeds 450 °C, the micro-cracks inside the granite develop and expand rapidly, and there is a gradual tendency to form a fracture network, resulting in a more significant effect of fracture initiation and permeability enhancement of the rock. The research results are of great significance for the development and utilization of hot dry rock and the evaluation of thermal reservoir connectivity and can provide useful references for rock engineering involving high-temperature thermal fracturing. Full article

This study investigated the effect of the number of sensors (8, 12, 16, and 20) on the measurement results of stress wave velocity in two-dimensional acoustic tomography of Hoop pine (Araucaria cunninghamii Sweet) trees and evaluated the method’s accuracy and operational efficiency in tree health diagnostics. Tests were conducted on five sample trees, two of which were confirmed to have internal damage using the drilling resistance method. The results showed that increasing the number of sensors improved image resolution and information completeness. However, differences in the average stress wave velocities among sensor configurations were not statistically significant (p ≥ 0.05), indicating limited overall velocity variation. In healthy trees, stress wave velocities measured with different sensor quantities (e.g., eight vs. twenty) exhibited weak linear correlations (R² = 0.06–0.58), reflecting a relatively uniform internal structure. In contrast, damaged trees showed strong consistency in velocity results (R² = 0.82–0.91, p < 0.01), with both minimum and average velocities being significantly lower than those in healthy trees. These findings demonstrate that acoustic tomography can effectively identify internal tree defects. Notably, even with only eight sensors, decay and cavities can still be accurately detected, which significantly enhances field inspection efficiency and reduces costs, thereby showing strong potential for practical applications. Full article

Background/Objectives: Epiretinal membrane (ERM) is often associated with macular thickening and foveal intraretinal fluid. The aim of this study was to evaluate the efficacy of early postoperative SMLT (577 nm) in preventing persistent macular oedema and to assess its impact on selected functional and morphometric retinal parameters after ERM peeling. Methods: A total of 68 pseudophakic patients with ERMs were enrolled and randomly assigned (1:1) to a laser group or a nonlaser control group. SMLT was performed one month after PPV. The functional and morphometric retinal parameters were assessed preoperatively and at one and four months postoperatively via optical coherence tomography (OCT), OCT angiography (OCTA), multifocal electroretinography (mfERG), and microperimetry. Results: The reduction in total retinal volume between the first and fourth postoperative months was significantly greater in the SMLT group than in the control group (p = 0.02). No significant differences in functional parameters were found between the groups. A more substantial reduction in total retinal volume post-SMLT was associated with greater baseline macular thickness, a more advanced ERM stage, worse baseline visual acuity, greater fixation stability, lower initial macular sensitivity and lower preoperative p-wave amplitude in ring R1 on mfERG. Conclusions: SMLT may be considered a therapeutic option in patients with advanced ERM stages and low preoperative visual acuity. Full article

The Jinchuan Cu–Ni sulfide deposit, one of only two ultra-large magmatic Ni–Cu–PGE deposits in Eurasia, is hosted in a small ultramafic intrusion at the southwestern margin of the Alxa block, North China Craton, and contains over five million tonnes of nickel. Previous studies suggest that its formation is linked to large-scale deep magmatic processes, but direct evidence from the mantle source region has been limited. Using P-wave seismic tomography, we imaged the crust and mantle beneath the Qilian–Longshoushan area, revealing a deep low-velocity anomaly at ~400 km depth, interpreted as residual mantle plume material. This anomaly spatially corresponds to the Jinchuan deposit, representing a long-term material and heat supply pathway for ore formation. A high-velocity anomaly at ~200 km depth, likely related to Indian plate subduction, influenced the Cenozoic tectonic evolution of the Longshoushan region. These results integrate geophysical, geochemical, and geological evidence, highlighting how deep mantle dynamics and associated magmatic activity controlled the supply of material to the Jinchuan Cu–Ni deposit and contributed to its formation. Full article

The South China block (SCB) is characterized by complex tectonics, large-scale lithospheric deformation, and extensive mineralization in its southeastern region. However, the geodynamic processes and mechanisms driving mineralization remain controversial, partly due to the lack of information on its fine crustal structure. The resolution of crustal seismic tomography is relatively low due to the uneven distribution of local earthquakes in South China. In this study, we conduct a joint inversion of Bouguer gravity and seismic travel-time data to investigate the detailed 3-D P-wave velocity (Vp) structure of the crust beneath the SCB. Our results show the following: (1) strong lateral heterogeneities exist in the crust, which reflect the surface geology and tectonics well; (2) the Vp patterns at different depths beneath the Yangtze block are almost consistent, but those beneath the Cathaysia block vary significantly, which might be related to the lithosphere thinning in the Mesozoic; (3) decoupling between the upper crust and the lower crust occurs at ~20 km depth beneath the eastern SCB; (4) the Vp patterns vary beneath different metallogenic belts; and (5) distinct low-Vp anomalies exist in the lower crust beneath mineral deposits. These results suggest that the deep mineralization is closely associated with the lithospheric thinning and upwelling thermal flow in the Mesozoic beneath the eastern SCB. Our Vp tomographic result also strongly supports the viewpoint that the mineralization mechanism varies for different metallogenic belts. Full article

This study presents a seismic tomography analysis of the Târgu Jiu region in southwestern Romania, an area that experienced an unusual earthquake sequence in 2023. Using P- and S-wave arrival times local earthquakes, we applied the LOTOS algorithm to produce high-resolution 3D crustal seismic velocities models. High Vp and Vs values in the northern and northeastern areas suggest the presence of dense, rigid geological formations, likely associated with consolidated magmatic or metamorphic units. In contrast, the central region exhibits low Vs values, coinciding with an active seismic zone and intersecting major fault structures. This suggests the presence of highly fractured and weakly consolidated rocks, potentially saturated with fluids. The Vp/Vs ratio in the central region reached values of ≥1.8–1.9, indicating fluid-filled fractures that may influence fault dynamics and earthquake occurrence. In the southern region, velocity anomalies suggest weakly consolidated sedimentary units with a high degree of fracturing. These findings contribute to a better understanding of the geodynamic behavior of the Târgu Jiu area and its seismic hazard potential. Full article

Background/Objectives: Aortic stiffness is a strong independent factor in cardiovascular outcomes. The method of choice for evaluating aortic stiffness is the measurement of aortic pulse wave velocity (PWV). Endovascular aortic repair (EVAR) increases aortic rigidity and thus aortic stiffness. The aim of this study is to investigate the correlation between endograft length and post-operative increases in PWV in patients with abdominal aortic aneurysms (AAAs) subjected to EVAR. Methods: A prospective observational study enrolling 107 patients from February to December 2025 was conducted. Patient demographics and comorbidities were recorded. The length of the endografts was calculated by studying computed tomography angiograms (CTAs) and digital subtraction angiographies (DSAs) of the patients. PWV was measured pre-operatively and post-operatively during the first 24 h after EVAR, and the difference in PWV (dPWV) was calculated. Results: The mean age of the patients was 72 ± 7.5 years, and 93.5% of them were males. The mean transverse AAA diameter was 5.7 ± 1.1 mm, and the mean endograft length was 169.7 ± 26.9 mm. An extension to the external iliac artery was deployed in 10 patients (9.3%). A strong positive correlation was observed between dPWV and endograft length, indicating that each additional 1 mm in graft length corresponded to a 0.541% increase in dPWV. Patients with an extension to external iliac arteries exhibited a significantly higher mean dPWV (9.95 ± 2.08% vs. 27.12% ± 12.15%, t = −4.463, p = 0.002). No statistically significant differences in dPWV between the different endograft types were found (p = 0.74). Conclusions: Endograft length is strongly related to PWV elevation during the immediate post-operative time after EVAR, especially when the endograft is extended to the external iliac arteries. Full article

Background and Objectives: The study investigates the relationship between accessible biomarkers and the extent of lung damage, assessed with computed tomography (CT) imaging, in patients hospitalized for COVID-19. Materials and Methods: This retrospective analysis was conducted in a hospital in Cluj-Napoca, Romania, and it includes 111 patients diagnosed with moderate to severe forms of COVID-19 during the Delta and Omicron waves. We evaluated the association of affordable lab works, such as C-reactive protein (CRP), procalcitonin, ferritin, neutrophil and lymphocyte counts, D-dimers, and albumin levels, with the extents of lung injury, pleural effusion, pulmonary embolism, and thoracic adenopathy. Results: Our data show that high CRP, neutrophil counts, ferritin, and procalcitonin levels, combined with lower lymphocyte and albumin levels, were significantly associated with >25% lung damage (p < 0.05). Elevated ferritin (≥274 ng/mL) and neutrophil counts (≥5.2 × 10⁹/L) were independently associated with this threshold. CRP (≥2.67 mg/dL), CRP/albumin ratio (≥0.736), and ferritin had the highest sensitivity (86.8%). D-dimer was the sole biochemical marker associated with pulmonary embolism (p = 0.036). Pleural effusion was independently associated with lymphocyte count (cut-off < 0.605 × 10⁹/L, p = 0.013). Thoracic lymphadenopathy was also associated with increased neutrophil counts and a heightened inflammatory response. Conclusions: These findings suggest that ferritin and the CRP/albumin ratio can serve as indicators for patients with extensive parenchymal damage. D-dimer levels were the only ones significantly associated with thromboembolic events, while lymphopenia appears to be a useful indicator of pleural involvement. Thus, these readily available biomarkers can prove useful in anticipating radiological severity in patients hospitalized with COVID-19. Full article

Preliminary tunnel surveys are essential for identifying geological hazards such as aquifers, faults, and karstic zones. While first-arrival tomography is effective for imaging shallow anomalies, traditional seismic sources face significant limitations in forested mountainous regions due to mobility, cost, and environmental impact. To address this, we deployed a seismic source delivered by an unmanned aerial vehicle (UAV) for a highway tunnel survey in Lijiang, China. The UAV system, paired with nodal geophones, enabled rapid, low-impact, and high-resolution data acquisition in rugged terrain. To enhance the weak far-offset refractions affected by near-surface attenuation, we applied supervirtual refraction interferometry (SVI), which significantly improved the signal-to-noise ratio and expanded the usable first-arrival dataset. The combined use of UAV excitation and SVI processing produced a high-precision P-wave velocity model through traveltime tomography, aligned well with borehole data. This model revealed the spatial distribution of weathered zones and bedrock interfaces, and allowed us to infer potential fracture zones. The results offer critical guidance for tunnel alignment and hazard mitigation in complex geological settings. Full article

Atrial fibrillation (AF) is increasingly recognized as the clinical manifestation of an underlying atrial disease process rather than a purely electrical disorder. This evolving paradigm has given rise to the concept of atrial cardiomyopathy (AtCM), encompassing structural, electrical, contractile, and molecular remodeling of the atrial myocardium that contributes to AF initiation, maintenance, and progression. Although consensus definitions of AtCM now exist, its integration into clinical practice remains limited, with AF management still largely guided by arrhythmic patterns rather than substrate characterization. This review synthesizes current diagnostic strategies for AtCM within the context of AF, emphasizing a multimodal approach. We outline advances in cardiac imaging—including echocardiography, cardiac magnetic resonance, and computed tomography—for detailed assessment of atrial morphology, function, and fibrosis. Electroanatomic mapping is discussed as a key invasive tool for substrate localization, while electrocardiographic indices such as P-wave morphology and dispersion serve as accessible surrogates of electrical remodeling. In parallel, we examine the role of circulating biomarkers and emerging genomic, transcriptomic, and epigenomic markers in refining disease phenotyping. Despite promising progress, significant challenges remain. Standardization of imaging protocols, validation of biomarker thresholds, and integration of artificial intelligence tools are needed to enhance clinical utility. A diagnostic framework informed by atrial substrate assessment may support more tailored therapeutic decision-making in AF. Future research should prioritize the harmonization of diagnostic criteria and explore how substrate profiling in AF may refine risk stratification and improve clinical outcomes. Full article

Pavement materials like hot mix asphalt (HMA) and cold recycled mixes (CRMs) are typically considered isotropic. This study evaluates the anisotropy of a cold in-place recycled (CIR) material using the shear wave velocity (V_s) parameter. The piezoelectric ring actuator technique (P-RAT) is utilized to assess the V_s parameter in three directions in CIR slabs. Similarly, the ultrasonic pulse velocity (UPV) technique is employed to measure P-wave velocities. Both methods evaluate mechanical properties in multiple directions. Complex modulus tests are conducted to link velocities results to |E*| modulus. Finally, computed tomography (CT) scans are performed on the specimens in order to evaluate anisotropy resulting from aggregate alignment. The V_s obtained using P-RAT and the V_p from UPV indicate anisotropy, as the wave velocities differ across the three directions. Differences range from 0.6 to 11.6% in V_s, influenced by measurement location. UPV results are analysed in relation to the |E*| modulus master curves, demonstrating that the first peak arrival time for the P-wave corresponds with the master curve. CT scan analysis reveals that the aggregates tend to be more aligned in the direction of the compacting wheel’s displacement, which also highlights anisotropy. Full article

Objective: This study investigated the shaping efficiency of four reciprocating systems—WaveOne Gold, Reciproc Blue, Excalibur, and One Reci—in three dimensional (3D) resin models of natural mandibular premolar teeth with two canals. Methods: Forty 3D-printed mandibular premolars (Vertucci configuration type V) were divided into four groups, each of which was assigned one of the reciprocating systems. According to the manufacturer’s protocols, each canal was prepared, with pre- and post-instrumentation micro computed tomography (micro-CT) scans evaluating canal volume, surface area, percentage of unprepared canal walls, and resin reduction in the pericervical area. Instrumentation time and screw-in sensation were recorded as qualitative performance indicators. Statistical analysis was performed using one-way ANOVA and chi-square tests with a significance of (p < 0.05). Results: All systems increased canal volume and surface area, primarily in the apical third, with Reciproc Blue and One Reci achieving the largest volume. WaveOne Gold had the highest percentage of unprepared walls (27.03%) and Reciproc Blue the lowest (19.65%), though these differences were not statistically significant (p > 0.05). Reciproc Blue caused the highest pericervical resin loss (22.24%), significantly higher than Excalibur (15.09%) and One Reci (15.17%) (p = 0.035). Reciproc Blue exhibited the highest incidence of screw-in sensation (70%), while WaveOne Gold achieved the shortest instrumentation time (86.7 s), although neither variable showed statistical significance. Conclusions: All systems effectively shaped complex canal anatomies, with Reciproc Blue demonstrating the highest dentin removal and WaveOne Gold proving the most time efficient. Clinically, these findings suggest that instrument selection should balance shaping efficiency with dentin preservation. Minimizing unprepared areas and preserving pericervical dentin are essential for enhancing disinfection and reducing the risk of root fractures, ultimately contributing to the long-term success of endodontic treatment. Full article

To study the mantle structure of the North China Craton (NCC) and its tectonic implications, in particular, the evolution of the rift systems in the Trans-North China Orogen (TNCO), we used teleseismic data recorded by 250 portable seismic stations to invert for the P-wave velocity (Vp) structures of the mantle beneath the NCC. Our results show a large-scale low-Vp anomaly in the shallow mantle and high-Vp anomalies in the deeper upper mantle beneath the eastern NCC, with fine-scale high-Vp anomalies at the lithosphere–asthenosphere boundary, indicating multi-stage lithospheric delamination during the Cenozoic. In the Yan Mountains (YanM), an east–west striking high-Vp anomaly between 60 to 200 km depths and low heat flow suggest the preservation of a thick mantle root. In the TNCO, high-Vp bodies in the upper mantle and the upper part of the mantle transition zone (MTZ) are imaged. The shallower high-Vp anomaly located beneath the Shanxi–Shaanxi Rift (SSR), along with an overlying local-scale low-Vp anomaly, indicates local hot material upwelling due to lithospheric root removal. The India–Eurasia collision’s far-field effects are proposed to cause lithospheric thickening, subsequent root delamination, and the formation and evolution of the SSR. Full article