Search Results (7,750)

Metallic ore deposits are generally formed through magmatic intrusions, followed by metamorphism. The geological structures in such regions are often complex, with mechanical parameters exhibiting significant variability. These characteristics dictate the need for refined geological modeling and heterogeneous mechanical parameters for rock mass stability analysis to ensure reliability. Therefore, this paper proposes a novel method for rock mass stability analysis. The method fully leverages high-density drilling data from the mine and introduces an intelligent rock quality designation (RQD) identification technique, facilitating characterization of the spatial heterogeneity of rock mass RQD. Building on this, laboratory experiment data and in situ measurements are integrated, and the Hoek–Brown criterion is employed to achieve a refined characterization of heterogeneous rock mass mechanical parameters. This method allows for a realistic inversion of in situ rock mass mechanical conditions, overcoming the limitations inherent in assigning uniform parameters. Finally, the computed rock mass mechanical parameters are assigned to the refined computational model to conduct rock mass stability analysis. Taking the Jiangfeng Iron Mine, with its complex geological conditions, as an example, this method enables the accurate evaluation of the rock mass stability, determines the feasibility of joint mining, and calculates the appropriate thickness of the isolation pillars, effectively mitigating safety risks in mining operations. This method provides a valuable reference for the rock mass stability analysis of underground joint mining operations for similar mines. Full article

Zero-tillage (ZT) is a conservation soil management approach which relies more heavily on herbicide application for weed control than in ploughed soil. Changes in soil management can influence the structure and organisation of pore space in soil, which drives changes in the transport of particulates and dissolved substances. Formulation of pesticides can be used to change the delivery of active ingredients to soil; however, it is currently unknown how changing the formulation of an herbicide can influence the transport properties between ZT vs. ploughing. We investigated the bioefficacy of two formulations of the herbicide atrazine, a pre- and post-emergence herbicide that inhibits photosystem II. Bioefficacy was assessed using physical measures and survival analysis of an early photosynthesis-dependent weed species, Amaranthus retroflexus L., over time, and soil pore network structure was assessed by analysing three-dimensional images produced by X-ray Computed Tomography. Increasing the herbicide application rate generally improved bioefficacy, though it was reduced in soils managed under ZT. Under herbicide-treated ZT samples, survival time was higher, ranging from 13.4 to 18.2 days compared with 12.6 to 15.4 days in ploughed samples, the mean dry plant mass was higher, ranging from 0.5 to 2.5 mg compared with 0.05 to 0.68 mg in ploughed samples, and the mean total plant length was higher, ranging from 1.73 to 12.1 mm compared with 0.2 to 5.45 mm in ploughed samples. Changes in the soil pore network previously demonstrated to be indicators of preferential transport were correlated with measures of bioefficacy, including pore thickness and connectivity density. Reduced atrazine efficacy under ZT is problematic considering the inherent reliance on chemical methods for weed control, we suggest that pursuing formulation strategies to alleviate potential risks of loss via preferential transport may be fruitful. Full article

Global climate variability is projected to result in more frequent and severe droughts, which can have adverse effects on New Zealand’s endemic tree species such as the iconic kauri (Agathis australis). Several studies have investigated the physiological response of kauri to medium- and long-term water stress; however, no research has used hyperspectral technology for the early detection and characterization of water stress in this species. In this study, physiological (stomatal conductance (g_s), assimilation rate (A), equivalent water thickness (EWT)) and leaf-level hyperspectral measurements were recorded over a ten-week period on 100 potted kauri seedlings subjected to control (well-watered) and drought treatments. In addition, plant functional traits (PTs) were retrieved from spectral reflectance data via inversion of the PROSPECT-D radiative transfer model. These data were used to (i) identify key PTs and narrow-band hyperspectral indices (NBHIs) associated with the expression of water stress and (ii) develop classification models based on single-date and multitemporal datasets for the early detection of water stress. A significant decline in soil water content and physiological responses (g_s and A) occurred among the trees in the drought treatment in weeks 2 and 4, respectively. Although no significant treatment differences (p > 0.05) were observed in EWT across the whole duration of the experiment, lower mean values in the drought treatment were apparent from week 4 onwards. In contrast, several spectral bands and NBHIs exhibited significant differences the week after water was withheld. The number and category of significant NBHIs varied up to week 4, after which a substantial increase in the number of significant indices was observed until week 10. However, despite this increase, the single-date models did not show good model performance (F1 score > 0.70) until weeks 9 and 10. In contrast, when multitemporal datasets were used, the classification performance ranged from good to outstanding from weeks 2 to 10. This improvement was largely due to the enhanced temporal and feature representation in the multitemporal models. Among the input NBHIs, water indices emerged as the most important predictors, followed by photochemical indices. Furthermore, a comparison of inverted and measured EWT showed good correspondence (mean absolute percentage error (MAPE) = 8.49%, root mean squared error (RMSE) = 0.0026 g/cm²), highlighting the potential use of radiative transfer modelling for high-throughput drought monitoring. Future research is recommended to scale these measurements to the canopy level, which could prove valuable in detecting and characterizing drought stress at a larger scale. Full article

Stylolites are ubiquitous structures in carbonates that present a variety of morphologies. Besides being important structures in terms of rock compaction and deformation, stylolites control limestone permeability, which is influenced by their morphology and arrangement in connected networks. This study characterizes stylolite morphological parameters, such as length, thickness, filling by insoluble material, spacing and connectivity, to provide quantitative data on the relationships between stylolite morphology and carbonate host rock textures. A collection of thin sections from a variety of lithologies and geological settings was analyzed, showing that the stylolite length, thickness and morphology are interrelated and are controlled by the host rock textures. The results show that stylolite linearity, calculated as the ratio between the straight length and the length measured along the stylolite trace, varies according to the stylolite type. Higher stylolite thickness is observed in mud-dominated textures compared to grain-dominated ones but is independent of the stylolite type. There is no clear trend in terms of the amount of insoluble material collected by the stylolites and the rock texture or stylolite type. Analysis of stylolite spacing reveals that heterogeneity in grain size, grain sorting and composition controls stylolite formation. Full article

Subclinical carotid artery disease anticipates major cardiovascular events, and previous studies show that low vitamin D levels are associated with arterial stiffening in hypertension. The aim of the study was to examine the relationship of 25-hydroxyvitamin D [25(OH)D] levels with subclinical carotid disease in hypertensive patients. In 223 middle-aged, nondiabetic, primary hypertensive patients free of major cardiovascular and renal complications, we measured 25(OH)D and parathyroid hormone (PTH) and assessed subclinical carotid arteries changes by B-mode ultrasonography. The carotid intima-media thickness (IMT) and presence of plaques were assessed together with measurements of indexes of carotid artery distensibility (coefficient of distensibility) or stiffening (Young’s elastic modulus; β-stiffness). Lower 25(OH)D levels were associated with older age (p < 0.001), longer duration of hypertension (p = 0.019), higher fasting plasma glucose (p = 0.037), and insulin (p = 0.044), Homeostatic Model Assessment (HOMA) index (p = 0.044), and PTH (p < 0.001). Insufficient and deficient 25(OH)D were associated with progressively greater carotid IMT (p < 0.001), frequency of carotid plaques (p = 0.026), Young’s elastic modulus (p = 0.002), and β-stiffness (p < 0.001), and progressively lower carotid coefficient of distensibility (p < 0.001). Serum levels of 25(OH)D were negatively correlated with age (p < 0.001), duration of hypertension (p = 0.006), fasting glucose (p < 0.001), HOMA index (p = 0.032), PTH (p < 0.001), carotid IMT (p < 0.001), Young’s elastic modulus (p = 0.025), and β-stiffness (p < 0.001), and positively related with carotid coefficient of distensibility (p < 0.001). Multivariate regression analysis showed that both higher carotid IMT (p = 0.004) and lower coefficient of distensibility (p = 0.002) were related to lower 25(OH)D independent of age, severity, and duration of hypertension and metabolic variables. In conclusion, deficiency/insufficiency of 25(OH)D independently predicts subclinical carotid disease in uncomplicated, middle-aged, hypertensive patients and might predispose these patients to major cardiovascular complications. Full article

This study aims to analyze the natural regeneration characteristics and the key factors of Quercus forests, providing a theoretical foundation for maintaining the ecological stability of Quercus forests in northern China. In June and July 2023, 17 square plots of five Quercus species in Beijing were surveyed, and seedling regeneration and environmental factors (site, stand and soil factors) were measured. Pearson correlation and random forest algorithms were used to identify the relevant and key environmental factors affecting seedling regeneration density (Seedling 1, Seedling 2, Seedling 3). The natural regeneration capabilities of the five Quercus species in the Beijing area vary, with Quercus aliena and Quercus variabilis being stronger, while Quercus mongolica, Quercus acutissima and Quercus dentata are relatively weaker. Correlation analysis showed that Seedling 1 has no significant correlation with environmental factors; Seedling 2 is significantly negatively correlated with Pielou’s evenness (J) and exchangeable calcium (ECa) (p < 0.05); Seedling 3 is significantly positively correlated with species richness (S), Shannon–Wiener index (H), stand volume (M), and litter layer thickness (LT) (p < 0.05), and significantly negatively correlated with Pielou’s evenness (J) (p < 0.01). The random forest algorithm indicated that the regeneration of Seedling 1 is mainly affected by stand factors, while the regeneration of Seedling 2 and Seedling 3 is more influenced by soil and site factors. The Quercus forests in the Beijing region exhibit a rich species composition and demonstrate a certain capacity for natural regeneration. However, seedling growth is more constrained by soil and site factors in the later stages. Therefore, in the management of Quercus forests, environmental factors can be regulated during the seedling growth stage to create more suitable conditions for regeneration. Full article

Background/Objectives: Hypertrophic cardiomyopathy (HCM) is the most common genetic heart disease. The most frequently mutated genes encode proteins of the thick filament of the sarcomere, while mutations in thin-filament genes are rare findings in HCM cohorts. Recent studies have revealed distinct mechanisms of disease development linked to thin-filament mutations, highlighting the need for further investigation into this rare subgroup. Methods: A total of 82 adult patients with sarcomere-positive HCM were enrolled. Baseline characteristics and nearly five years of follow-up data from 15 patients with thin-filament mutations were analyzed and compared with those from 67 patients with thick-filament mutations and findings from other studies. Results: Compared to thick-filament HCM patients, individuals with thin-filament mutations exhibited significantly lower maximum left ventricular wall thickness, as measured by both echocardiography (p = 0.024) and cardiac magnetic resonance (p = 0.006), showed more rapid progression to advanced heart failure (HR = 5.6, p = 0.018), and less often underwent septal reduction therapy (p = 0.025). None of the thin-filament HCM patients experienced malignant arrhythmic events. Conclusions: In adults, thin-filament HCM is associated with a ‘thinner’ phenotype and a more rapid progression to advanced heart failure compared to thick-filament HCM. Data on a higher risk of malignant arrhythmias in thin-filament HCM remain controversial between studies and rather depend on the age of onset and genotype in each particular family. Full article

This study addresses the unique challenge of the partition walls in subway stations, featuring high height, fire prevention, and located outside the main frames, by introducing a confined autoclaved aerated concrete (AAC) panel wall system. Different from studies on a main frame with infill walls, this study aimed to explore the seismic performance of partition walls, which were fabricated with confined high AAC panel walls and located outside the main frames. A custom-designed partition wall, measuring 6600 mm in height, 3400 mm in width, and 200 mm in thickness, underwent cyclic testing. A detailed analysis of specimen’s failure modes was conducted, focusing on seismic behavior such as hysteresis curves, envelope curves, ductility, stiffness degradation, and energy-dissipation capacity. Additionally, the study delved into shear deformation, relative slippage between AAC panels, and reinforcement strains within the specimen. Finally, the D-value method for calculating the initial stiffness of the confined high AAC panel walls and the weak sub-structural approach for determining the load-bearing capacity of confined high AAC panel walls were proposed and validated. The results indicate that the strength degradation factor of the confined high AAC panel walls ranges from 0.971 to 0.716. The drift of its upper portion accounts for 76.94–83.63% of the total drift, while the energy dissipation factor of its upper portion is 0.8–4.8% higher than that of the entire specimen. The yield and ultimate drift rotations of the entire confined high AAC panel wall and its upper portions satisfy the elastic and elastic-plastic inter-story drift rotation limits specified in the Chinese code. The calculated initial stiffness of the confining frame, obtained using the D-value method, closely aligns with experimental results, with a deviation of only 2.48%. Additionally, the load-bearing capacity calculated using the weak sub-structural approach deviates from the experimental average by just 4.30%. Full article

This work presents results on nanosecond laser ablation of a titanium (Ti) plate immersed in a liquid medium using the fundamental wavelength (1064 nm) of a nanosecond Nd:YAG laser system. The laser radiation was focused on the target surface as scanning was accomplished by an XY translation stage. The laser processing of the Ti targets took place in two organic liquids—liquid paraffin and diesel oil. The morphology of the structured surfaces and the structure and phase composition of the samples were studied; their dependences on the processing parameters are discussed. With both liquid media used, crack formation on the surface of the laser-treated Ti target was observed. Formation of a titanium carbide (TiC) phase was found whose properties could be tuned by varying the laser irradiation parameters. Raman measurements were utilized to analyze the carbon structure formed in the resulting coatings. The results of surface electron microscopy reveal that the thickness of the resulting coatings reached 20 µm. Some of the obtained coatings demonstrated about three times higher hardness compared to the native Ti sample. The technique proposed can be used in surface modification of materials in view of improving their mechanical properties. Full article

Background/Objectives: To appraise the mandibular bone structure of patients with rheumatoid arthritis (RA) who were treated with different drugs using fractal dimension (FD) analysis and panoramic radiomorphometric indices and investigate the effects of RA on the jaw bone. Methods: A total of 90 panoramic radiographs were analyzed in this study: 30 were from patients with RA using conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) and glucocorticoids, 30 were from patients with RA using tumor necrosis factor-alpha (TNF-α) inhibitors, and 30 were from systemically healthy individuals. In panoramic radiographs, panoramic mandibular index (PMI), mandibular cortical thickness measurements, mandibular cortical index (MCI), and FD analysis taken from four different regions were evaluated. Results: The lowest FD analysis value was observed in patients using csDMARDs and glucocorticoids and in the condyle region (p = 0.001). Although PMI and posterior index (PI) were found to be significantly lower in patients using csDMARDs and glucocorticoids compared with the others (p = 0.001), no significant difference was observed between the groups in terms of anterior index (AI), symphysis index (SI), and molar index (MI) values (p > 0.05). When MCI was analyzed, there was no significant difference between the groups (p > 0.05). Conclusions: It was observed that the trabecular structure in the condyle and posterior region of the mandible was negatively influenced by RA and csDMARD and glucocorticoid drug use. Radiomorphometric indices and FD analysis on panoramic radiographs can be used to evaluate osteoporotic alterations in individuals with RA. These assessments are valuable in predicting the prognosis of conditions such as bone healing after tooth extraction and other surgical procedures and osseointegration after implant surgery. Full article

Due to the bio-inert nature of titanium (Ti) and subsequent accompanying chronic inflammatory response, an implant’s stability and function can be significantly affected, which is why various surface modifications have been employed, including the deposition of titanium oxide (TiO₂) nanotubes (TNTs) onto the native surface through the anodic oxidation method. While the influence of nanotube diameter on cell behaviour and osteogenesis is very well documented, information regarding the effects of nanotube lateral spacing on the in vivo new bone formation process is insufficient and hard to find. Considering this, the present study’s aim was to evaluate the mechanical properties and the osteogenic ability of two types of TNTs-based pins with different lateral spacing, e.g., 25 nm (TNTs) and 92 nm (spTNTs). The mechanical properties of the TNT-coated implants were characterised from a morphological point of view (tube diameter, spacing, and tube length) using scanning electron microscopy (SEM). In addition, the chemical composition of the implants was evaluated using X-ray photoelectron spectroscopy, while surface roughness and topography were characterised using atomic force microscopy (AFM). Finally, the implants’ hardness and elastic modulus were investigated using nanoindentation measurements. The in vivo new bone formation was histologically evaluated (haematoxylin and eosin—HE staining) at 6 and 30 days post-implantation in a rat model. Mechanical characterisation revealed that the two morphologies presented a similar chemical composition and mechanical strength, but, in terms of surface roughness, the spTNTs exhibited a higher average roughness. The microscopic examination at 1 month post-implantation revealed that spTNTs pins (57.21 ± 34.93) were capable of promoting early new bone tissue formation to a greater extent than the TNTs-coated implants (24.37 ± 6.5), with a difference in the average thickness of the newly formed bone tissue of ~32.84 µm, thus highlighting the importance of this parameter when designing future dental/orthopaedic implants. Full article

Frequent agricultural irrigation events continuously raise the groundwater table on loess platforms, triggering numerous loess landslides and significantly contributing to soil erosion in the Chinese Loess Plateau. The movement of irrigation water within the surficial loess layer is crucial for comprehending the mechanisms of moisture penetration into thick layers. To investigate the infiltration and evaporation processes of irrigation water, a large undisturbed soil column with a 60 cm inner diameter and 100 cm height was extracted from the surficial loess layer. An irrigation simulation event was executed on the undisturbed soil column and the ponding infiltration and subsequent evaporation processes were systematically monitored. A ruler placed above the soil column recorded the ponding height during irrigation. Moisture probes and tensiometers were installed at five depths to monitor the temporal variations in volumetric water content (VWC) and matric suction. Additionally, an evaporation gauge and an automatic weighing balance measured the potential and actual evaporation. The results revealed that the initially high infiltration rate rapidly decreased to a stable value slightly below the saturated hydraulic conductivity (K_s). A fitted Mezencev model successfully replicated the ponding infiltration process with a high correlation coefficient of 0.995. The monitored VWC of the surficial 15 cm-thick loess approached a saturated state upon the advancing of the wetting front, while the matric suction sharply decreased from an initial high value of 65 kPa to nearly 0 kPa. The monitored evaporation process of the soil column was divided into an initial constant rate stage and a subsequent decreasing rate stage. During the constant rate stage, the actual evaporation closely matched or slightly exceeded the potential evaporation rate. In the decreasing rate stage, the actual evaporation rate fell below the potential evaporation rate. The critical VWC ranged from 26% to 28%, with the corresponding matric suction recovering to approximately 25 kPa as the evaporation process transitioned between stages. The complete evaporation process was effectively modeled using a fitted Rose model with a high correlation coefficient (R² = 0.971). These findings provide valuable insights into predicting water infiltration and evaporation capacities in loess layers, thereby enhancing the understanding of water movement within thick loess deposits and the processes driving soil erosion. Full article

Background: Rheumatoid arthritis (RA) is a chronic autoimmune disease, and it is currently incurable. Tetrandrine (TET) has an obvious curative effect with therapeutic efficacy on RA, but its use is limited due to its poor water-solubility and bioavailability. Therefore, TET-loaded nanomicelles modified with chitosan, stearic acid, and folic acid (FCST) was prepared in the study, and the pharmacokinetics and pharmacodynamics were studied. Methods: The plasma concentrations of FCST and TET were measured by the PLC-MS/MS method at different times, and the pharmacokinetic parameters were calculated. A collagen-induced arthritis (CIA) model was established with rats. On the 16th day after the first immunization, 50 rats were randomized into five groups with 10 rats in each group according to the arthritis score. The drugs were administered by intraperitoneal injection for 30 days. The swelling degree and joint score of the rats were tested during each administration. In addition, the pro-inflammatory factors IL-1β, IL-6, IL-17, and TNF-α in the serum of the rats were tested by an ELISA kit, and their joints were examined by histopathology. Results: Pharmacokinetic studies showed that the AUC_0–72h of FCST was 1.93 times that of TET. FCST demonstrated higher bioavailability compared to TET (p < 0.05). Pharmacodynamic studies demonstrated that FCST had significant anti-inflammatory effects, and its anti-inflammatory activity was stronger compared to the same dose of TET, as evidenced by measuring toe thickness and observing toe appearance. It significantly reduced the expression of IL-1, IL-6, IL-17, and TNF-α in rats with rheumatoid arthritis (p < 0.05). Conclusions: FCST can significantly improve bioavailability and has a significant therapeutic effect on rheumatoid arthritis. Full article

Mīnā’ī wares, crafted during the 12th–13th centuries, represent some of the earliest examples of sophisticated painted enamel decoration by potters. Due to the thinness of these enamel layers, their detailed characterization remains challenging, even with the use of advanced techniques, such as Proton-Induced X-ray Emission (PIXE) analysis and Rutherford Backscattering Spectrometry (RBS). This study provides the first combined non-invasive analysis, using X-ray fluorescence (XRF) and Raman spectroscopy, of five shards attributed to mīnā’ī wares. For comparison, two İznik shards from the 17th century, which feature similarly styled but thicker enamel decorations, were also analyzed. Interestingly, the mīnā’ī paste was found to contain lead and tin, suggesting the use of a lead-rich frit in its composition. This finding was confirmed through micro-destructive analysis, using Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM–EDS). Elements, such as rubidium (Rb), strontium (Sr), yttrium (Y), and zirconium (Zr), produced significant XRF signals and effectively distinguished mīnā’ī wares from İznik wares. A uniform tin-rich glaze, measuring 300–500 µm in thickness, was used as a base layer for the much thinner painted mīnā’ī enamels. The colored areas (blue, turquoise, red, green, black, white, eggplant) revealed the presence of various coloring agents and phases, such as spinels, chromite, and ions like Cu²⁺ and Co²⁺, as well as opacifiers like cassiterite and lead–calcium/potassium arsenates. Two distinct cobalt sources were identified: one associated with arsenic and the other with manganese and nickel. These cobalt sources are comparable to those used in İznik pottery. For the first time, boron was detected in the blue enamel of mīnā’ī wares. Full article

Background/Objectives: The purpose of this study was to preoperatively estimate the four-strand hamstring graft size in a White Caucasian population, using anthropometric data. Methods: This was a prospective study of a consecutive series of fifty patients with anterior cruciate ligament (ACL) rupture, who were scheduled for reconstruction using hamstring autografts; however, one of them was ultimately not enrolled according to the exclusion criteria (49 patients in total). Preoperatively, age, sex, weight, body mass index (BMI), length, and diameter of the contralateral thigh, length of the harvested gracilis/semitendinosus tendons, and length and thickness of the four-stranded graft were recorded. Graft diameter and length were dependent variables, measured via a graft sizer and a ruler, respectively. Quantitative variables were described with mean ± SD (correlated in a pairwise manner with Pearson’s r correlation). Qualitative variables were described with an absolute count (relative % percent) per categorical level, and their dependency on any quantitative (dependent) variable was assessed via Student’s t-test. Results: The mean lengths of the gracilis and semitendinosus were 25.6 ± 3.2 cm and 28.4 ± 3.3 cm, respectively, and they were positively correlated with the length of the four-strand hamstring graft along with the patients’ height and thigh length. Conclusions: The use of anthropometric data can assist in the prediction of the hamstring autograft size, aiding the selection of an appropriate graft type. The four-strand hamstring graft length was related to the gracilis, semitendinosus, and thigh length. The patients’ height was related to the graft length and diameter. Full article