Search Results (516)

Rock mechanical parameters can provide fundamental data for the numerical simulation of hydraulic fracturing, aiding in the construction of hydraulic fracturing models. Due to the laminated nature of shale, constructing a hydraulic fracturing model requires obtaining the rock mechanical parameters of each lamina and the bedding planes. However, acquiring the mechanical parameters of individual shale laminas through physical experiments demands that, after rock mechanics testing, cracks propagate along the centre of the laminae without connecting additional bedding planes, which imposes extremely high requirements on shale samples. Current research on the rock mechanics of the Minfeng subsag shale is relatively limited. Therefore, to obtain the rock mechanical parameters of each lamina and the bedding planes in the Minfeng subsag shale, a numerical simulation approach can be employed. The model, built using PFC2D, is based on prior X-ray diffraction (XRD) analysis, conventional thin-section observation, scanning electron microscopy (SEM), Brazilian splitting tests, and triaxial compression tests. It replicates the processes of the Brazilian splitting and triaxial compression experiments, assigning initial parameters to different bedding planes based on lithology. A trial-and-error method is then used to adjust the parameters until the simulated curves match the physical experimental curves, with errors within 10%. The model parameters for each lamina at this stage are then applied to single-lithology Brazilian splitting, biaxial compression, and three-point bending models for simulation, ultimately obtaining the tensile strength, uniaxial compressive strength, Poisson’s ratio, Young’s modulus, brittleness index, and Mode I fracture toughness for each lamina. Simulation results show that the Minfeng subsag shale exhibits strong heterogeneity, with all obtained rock mechanical parameters spanning a wide range. Calculated brittleness indices for each lamina mostly fall within the “good” and “medium” ranges, with carbonate laminae generally demonstrating better brittleness than felsic laminae. Fracture toughness also clearly divides into two ranges: mixed carbonate shale laminae have overall higher fracture toughness than mixed felsic laminae. Full article

Free-roaming cats may contribute to zoonotic risk via parasites and other eukaryotic taxa, yet surveillance in protected island settings is limited and conventional coprology can miss low-intensity or degraded signals. We conducted a cross-sectional 18S rRNA metabarcoding survey to establish a baseline profile of potentially pathogenic eukaryotes in community cats from La Graciosa (Natura 2000, Canary Islands, Spain) prior to large-scale antiparasitic interventions. We analysed 152 faecal samples, including fresh samples collected during a high-throughput TNR campaign (n = 37) and dry environmental deposits (n = 115). Host amplification was reduced using a feline 18S blocking primer; libraries were sequenced with Oxford Nanopore technology; and taxonomy was assigned using SILVA-based classifiers with downstream filtering for veterinary/zoonotic relevance. After quality control, 72 eukaryotic taxa were retained and DNA from at least 24 potentially pathogenic taxa was detected. Dipylidium caninum was most frequent (74.3%; 113/152), and opportunistic fungi/yeasts were common (e.g., Pichia kudriavzevii 42.4%, Diutina catenulata 31.5%). Zoonotic protozoa showed low-to-moderate detection frequency (Acanthamoeba castellanii 13.3%, Toxoplasma gondii 7.9%, Balamuthia mandrillaris 4.6%). Overall richness did not differ between fresh and dry samples (p > 0.05), but fresh samples contained higher richness of potentially pathogenic taxa (p < 0.01). Full article

Background/Objectives: This study evaluates the penetration of a calcium silicate-based sealer (BC Universal) into dentinal tubules after different final irrigation protocols. Methods: Eighty-four single-rooted extracted teeth were instrumented with ProTaper Gold to size F4 and assigned to four groups (n = 21) according to the final irrigation protocol as follows: conventional needle irrigation (CNI), sonic agitation with EndoActivator (EA), ultrasonic activation (UA), and XP-Endo Finisher (XPF). A total of 20 canals from each group were filled with BC Universal sealer mixed with fluorescein and the single-cone obturation technique. The remaining specimen in each group served as a negative control to assess potential imaging bias. Specimens were sectioned 3 mm from the apex and analyzed under confocal laser scanning microscopy. Sealer penetration was assessed by penetration area (PA), maximum depth (MaxD), mean depth (MeanD), and percentage of canal perimeter infiltrated (P). Data were analyzed using Kruskal–Wallis or ANOVA tests (α = 0.05). Results: All activation/agitation techniques showed significantly higher penetration than CNI across all variables (p < 0.001). No significant differences were found among EA, PUI, and XPF for PA, MaxD, and MeanD. However, XPF exhibited the highest perimeter infiltration, which was significantly greater than EA and UA (p < 0.001). Conclusions: Irrigant activation significantly enhanced dentinal tubule penetration of BC Universal sealer compared to CNI. XPF provided superior P, suggesting superior circumferential distribution. These findings suggest a more effective cleaning of the root canal in the apical third achieved by the tested irrigant activation/agitation techniques, which may improve the sealing potential of BC Universal sealer. Full article

Modifications in leaf architecture disrupt optical properties and internal light-scattering dynamics. Accurate modeling of leaf-scale light scattering is therefore essential not only for understanding how disease affects the availability of light for chlorophyll absorption, but also for evaluating its potential as an early optical marker for plant disease detection prior to visible symptom development. Conventional ray-tracing and radiative-transfer models rely on high-frequency approximations and thus fail to capture diffraction and coherent multiple-scattering effects when internal leaf structures are comparable to optical wavelengths. To overcome these limitations, we present a GPU-accelerated finite-difference time-domain (FDTD) framework for full-wave simulation of light propagation within plant leaves, using anatomically realistic dicot and monocot leaf cross-section geometries. Microscopic images acquired from publicly available sources were segmented into distinct tissue regions and assigned wavelength-dependent complex refractive indices to construct realistic electromagnetic models. The proposed FDTD framework successfully reproduced characteristic reflectance and transmittance spectra of healthy leaves across the visible and near-infrared (NIR) ranges. Quantitative agreement between the FDTD-computed spectral reflectance and transmittance and those predicted by the reference PROSPECT leaf optical model was evaluated using Lin’s concordance correlation coefficient. Higher concordance was observed for dicot leaves ($C_b=0.90$) than for monocot leaves ($C_b=0.79$), indicating a stronger agreement for anatomically complex dicot structures. Furthermore, simulations mimicking an early-stage fungal infection in a dicot leaf—modeled by the geometric introduction of melanized hyphae penetrating the cuticle and upper epidermis—revealed a pronounced reduction in visible green reflectance and a strong suppression of the NIR reflectance plateau. These trends are consistent with experimental observations reported in previous studies. Overall, this proof-of-concept study represents the first full-wave FDTD-based optical modeling of internal light scattering in plant leaves. The proposed framework enables direct electromagnetic analysis of pre- and post-penetration light-scattering dynamics during early fungal infection and establishes a foundation for exploiting leaf-scale light scattering as a next-generation, pre-symptomatic diagnostic indicator for plant fungal diseases. Full article

Background: Patients are the most frequent perpetrators of physical violence against nurses. In the United States, most states have established laws designating assault against nurses a felony, or serious crime. It is unknown what reasons nurses have for pressing charges or not pressing charges against patients. Purpose: The purpose of this study was to examine nurses’ decisions regarding pressing charges when patients exhibit violent behavior. Methods: This study used a mixed-method, cross-sectional, descriptive design. Three unfolding case studies were presented in an electronic survey. Twelve versions of the survey were randomly assigned to participants. Each described an adolescent, adult, and geriatric patient. The narrative descriptions were identical, but the visual representations of the patients differed. Results: A total of 499 nurses from seven hospitals in the western United States responded. Most nurses indicated that they would not press charges against any of the hypothetical patients. An injury occurring and an assumption of intentionality contributed to nurses’ decisions to press charges. Participants were more likely to press charges against the adolescent and adult patients than the geriatric patient. The hypothetical adolescent and geriatric patients were more likely to have charges pressed against them if presented as female than if presented as male. The hypothetical adult patient was more likely to have charges pressed against them if presented as white than if presented as black. Conclusions: There is no consensus regarding when a nurse ought to pursue legal action against a patient who exhibits violent behavior. In addition to the presence of injury and the assumption of intentionality, it is possible that implicit bias may also play a role in these decisions. More investigation into this is needed. Full article

Mothers face high depression risks during pregnancy, and untreated depression can harm both mother and baby. Vortioxetine is a novel antidepressant with a multimodal mechanism, unlike traditional ones. However, little is known about its safety and effectiveness in pregnancy due to limited preclinical and clinical data. This study investigated how maternal vortioxetine exposure during pregnancy affects DNA methylation in the brain tissue of mother and offspring rats. It also explored putative structural interactions of vortioxetine through molecular docking with key epigenetic enzymes to provide a hypothesis-generating context. Fifty female Sprague-Dawley rats were screened using a repeated forced-swim paradigm to characterize a passive stress-coping phenotype. They were then mated and randomly assigned to five groups (n = 10 each): vortioxetine at 0.5, 1.0, 2.0 mg/kg/day orally, saline control, and escitalopram (2.6 mg/kg/day orally) as a comparison. Treatments were given throughout pregnancy. On the day of cesarean section (G20), brain tissue was collected from both the mother and fetus. Global 5-mC levels were measured with ELISA (three replicates). The binding affinities and interaction motifs of vortioxetine and escitalopram with TET2, DNMT3A, and DNMT3B were analyzed via molecular docking. Global 5-mC levels in brain tissue did not differ between groups. However, a significant decrease in overall methylation was observed in offspring given the highest dose of vortioxetine (2.0 mg/kg/day). Docking analyses revealed that vortioxetine and escitalopram could bind strongly to TET2 and DNMT3A/3B; the observed reduction in global 5-mC was compatible with the hypothesis of altered de novo methylation pathways. The results show a specific dose threshold for the fetus. Low to moderate maternal exposures were not associated with detectable differences in global 5-mC under the current assay conditions, whereas high exposure was associated with hypomethylation in offspring. These findings underscore the importance of careful dose selection and mechanism validation for vortioxetine. Full article

Background/Objectives: Gastrointestinal and eating disorders are highly prevalent problems in children with Down syndrome (DS) and have a significant impact on their daily lives. It is important to investigate the bowel habits of children with DS, specifically the prevalence of functional constipation (FC), in order to develop practice guidelines for pediatricians that support diagnosis and treatment. Materials and Methods: This observational, analytical, and cross-sectional study was approved by the Ethics Committee and included 36 children with DS under pediatric outpatient follow-up at a university hospital. To assess bowel habits, an interview was held with the parents using the Rome IV criteria and the Bristol Stool Scale. The children were divided into two groups: those with and those without FC. Specific curves for individuals with DS were used for nutritional assessment. Results: The median age of the children was 46.6 months (5 to 144 months); a total of 80.5% of those included were eutrophic. The median age at initiation of toilet training was 36 months. Most children achieved bowel control when training started after 30 months of age. A total of 15 (41.7%) of the 36 children included were assigned to the group with FC, and 21 (58.3%) were assigned to the group without FC. The FC group had a lower frequency of bowel movements, hardened stools, pain during bowel movement, and used laxatives. According to the Rome IV criteria, the three most prevalent criteria were hard stools, large-volume stools, and painful bowel movements. Conclusions: Children with DS had a high prevalence of FC, and it was possible to identify an association between delayed sphincter training and FC. A care and monitoring protocol and flowchart are useful tools for the general pediatrician. Full article

The present paper concerns a new formulation of the optimal design problem of I-shaped multistep steel beam elements, based on the study of the plastic strain spread occurring in the relevant elements, with the aim of determining the length involved by the plastic deformation related to assigned load conditions and different constrained beam schemes. Material behavior is assumed as elastic–perfectly plastic, and the hypothesis of plane cross-sections is accepted. The functions defining the plastic strain spread are analytically obtained in the framework of Euler–Bernoulli beam theory. The proposed optimal design problem is a minimum volume one and the new constraint imposed on the length of the plasticized portion ensures that the minimum volume beam element also represents a maximum plastic dissipation one. Furthermore, the solution to the optimal design problem guarantees that the obtained multistep beam element ensures protection against brittle failure of the beam end sections, provides optimal cross-sections of the different portions belonging to Class 1 and ensures a suitable minimum value of the elastic flexural stiffness to respect the constraint on the deflection. Explicit reference is made to the so-called Reduced Beam Section (RBS), which characterizes the described multistep beam elements. Actually, the proposed formulation represents an innovative approach to obtaining an optimal beam element that really satisfies all the resistance, stiffness and ductility behavioral requirements. Some numerical applications conclude the paper, and their results are confirmed by appropriate FEM analyses in ABAQUS environment. Full article

Background: Left ventricular systolic dysfunction (LVSD) is a major determinant of prognosis in patients with ischemic heart disease. Electrocardiography (ECG) is widely available, inexpensive, and may aid in identifying patients at risk. We hypothesized that a composite score derived from multiple established ECG markers could improve the detection of LVSD in patients with stable angina. Methods: In this single-center, cross-sectional study, 177 patients undergoing elective coronary angiography for stable angina were included. Patients were classified as LVSD-negative (n = 123) or LVSD-positive (n = 54) based on echocardiographic ejection fraction. ECG parameters, including fragmented QRS, pathologic Q waves, R-wave peak time, QRS duration, and frontal QRS–T angle, were assessed. Independent predictors of LVSD were identified using multivariate logistic regression. A composite ECG score was constructed by assigning one point to each abnormal parameter. Model robustness was evaluated using bootstrap resampling (1000 iterations) and 10-fold cross-validation. Results: Multivariable analysis identified prior stent implantation, fragmented QRS, pathological Q waves, R-wave peak time, frontal QRS–T angle (log-transformed), and QRS duration as independent predictors of LVSD. ROC analysis demonstrated good discriminatory performance for R-wave peak time (AUC 0.804), QRS duration (AUC 0.649), and frontal QRS–T angle (AUC 0.825) measurements. The composite ECG score showed a stepwise association with LVSD: a score of ≥2 yielded high sensitivity (88%) and negative predictive value (97%), whereas a score of ≥3 provided high specificity (100%) and positive predictive value (100%). Bootstrap resampling and cross-validation confirmed model stability and strong discriminatory performance (mean AUC, 0.964; accuracy, 0.91). Conclusions: A simple composite ECG score integrating multiple established ECG markers is associated with the robust detection of LVSD in patients with stable angina. Although not a substitute for echocardiography, this score may support early risk stratification and help identify patients who warrant further imaging evaluations. External validation in larger and more diverse populations is required before routine clinical implementation of this model. Full article

Although an edition of Petrus Hispanus’ commentary on Pseudo-Dionysius’ De divinis nominibus has long been available, his contribution to the pivotal question of beauty—so extensively explored by medieval commentators on this treatise—has remained virtually unnoticed. This article seeks to address that lacuna by examining the principal passages devoted to beauty, primarily in Chapter 4, where Pseudo-Dionysius’s presents God as subsistent beauty and as the source of both good and beauty, thereby articulating a profound connection between goodness, beauty and being. The study undertakes a comparative analysis of Petrus Hispanus’ commentary and the gloss on the same Dionysian text by Thomas Gallus, upon whom Petrus Hispanus depends to a considerable degree. This comparison reveals that, in the section on beauty, Petrus Hispanus offers a richer and more nuanced treatment than Gallus’ paraphrase. The theme of beauty emerges in close relation to the soul’s ascent toward God within a Christian framework deeply shaped by Neoplatonic thought. While Petrus Hispanus retains traditional descriptions of beauty—such as harmony or order—he also emphasizes its intelligible nature more strongly than either Dionysius or Vercelli did, assigning to the intellect a privileged role in the apprehension of beauty. Full article

The first comprehensive study about of amber from the Lower Cretaceous of the Lusitanian Basin, in the Estremadura region of western Portugal, is here reported. The amber was recovered as isolated clasts in the Portela da Vila outcrop section, near the small villages of Ramalhal and Ameal, from sedimentary deposits belonging to the Lugar d’Além Formation considered to be of Hauterivian age. The chemical composition of amber clasts was examined in order to infer their botanical source via biomarker analysis. GC–MS and GC×GC–TOFMS showed a strong predominance of abietane-type diterpenoids, including compounds such as amberene, ferruginol (phenolic abietane), kaurane and the derivative of clerodane. The dominance of abietane diterpenoids along with these specific biomarkers is consistent with resin exudation by Araucariaceae/Cheirolepidiaceae conifers, as supported by previous chemotaxonomic studies of Cretaceous amber. Palynological studies of the same sedimentary rock samples highlighted a pollen–spore assemblage characterized by low diversity and number of specimens, and dominated by conifer pollen assigned to the genera Classopollis, Araucariacites and coniferous bisaccate pollen, with relative occurrences of fern spores. The combined geochemical and palynological studies strongly support a source related to conifer plants for the amber here reported. Full article

The integration of artificial intelligence (AI) tools, such as the chat generative pre-trained transformer (ChatGPT), into health professions education is rapidly accelerating, creating new opportunities for personalized learning and clinical preparation. These tools have demonstrated the potential to enhance learning efficiency and critical thinking. However, concerns regarding reliability, academic integrity, and potential overreliance highlight the need to better understand how healthcare students adopt and perceive these technologies in order to guide their effective and responsible integration into educational frameworks. This nationwide, cross-sectional, survey-based study was conducted between February and April 2024 among undergraduate students enrolled in medical, pharmacy, nursing, dental, and allied health programs in Saudi Arabia. An online questionnaire collected data on ChatGPT usage patterns, satisfaction, perceived benefits and risks, and attitudes toward integrating them into the curricula. Among 1044 participants, the prevalence of ChatGPT use was 69.25% (n = 723). Students primarily utilized the tool for content summarization, assignment preparation, and exam-related study. Key motivators included time efficiency and convenience, with improved learning efficiency and reduced study stress identified as major benefits. Conversely, major challenges included subscription costs and difficulties in formulating effective prompts. Furthermore, concerns regarding overreliance and academic misconduct were frequently reported. In conclusion, the adoption of generative AI tools such as ChatGPT among healthcare students in Saudi Arabia was high, driven by its perceived ability to enhance learning efficiency and personalization. To maximize its benefits and minimize risks, institutions should establish clear policies, provide faculty oversight, and integrate AI literacy into the education of health professionals. Full article

This study evaluated the push-out bond strength (PBS) and failure modes of fiber posts cemented with silane-containing self-adhesive resin cement (SARC) compared with conventional SARC and universal adhesive strategies, considering the effects of root section and aging. Ninety single-rooted human premolars were equally assigned to three cementation protocols: silane-containing SARC (PANAVIA SA Cement Universal), conventional SARC (RelyX Universal), and universal adhesive plus SARC (Scotchbond Universal Plus + RelyX Universal). Each group was divided into two aging subgroups: 24 h water storage and thermal cycling (10,000 cycles between 5 °C and 55 °C, 30 s dwell time; n = 15). After root canal treatment and post space preparation, glass fiber posts were cemented, and each root was sectioned to obtain six slices. PBS was measured using a push-out test, and failure modes were examined under stereomicroscopy. Data were analyzed using three-way ANOVA, post hoc tests, Spearman’s correlation, and logistic regression (α = 0.05). Cement type, root section, and aging significantly influenced PBS (p < 0.001). PBS decreased from coronal to apical sections, and thermal cycling reduced PBS in all groups. The universal adhesive plus SARC achieved the highest PBS, while conventional SARC had the lowest PBS. Cementdentin adhesive failures (FM2) predominated overall, with proportions varying between 43% and 90%, and higher PBS values were associated with fewer FM2 failures. The combination of a universal adhesive with SARC provided superior bonding compared to simplified protocols. Although silane-containing SARC improved bonding relative to conventional SARC, durable adhesion to radicular dentin remains challenging, particularly in apical regions. Full article

In parallel with achieving its 2040 Vision toward establishing smart cities, this study aims to pinpoint promising locations for future urban development in Oman, which reflect the unique physical attributes of the country, its renewable energy resources, and socio-economic conditions. To meet this goal at the national scale, the research relied on the following key factors: topography, diurnal temperature range, relative humidity, dust concentrations, wind speed, solar radiation, and access to electricity. These inputs were derived from remote sensing sources. A multi-layer spatial analysis was carried out within a Geographical Information System (GIS) environment to identify high-priority locations for future and sustainable urban growth. All parameters were assigned equal weights, particularly when applying a standard approach to produce a baseline suitability model at the national scale and to avoid subjective bias in the overall suitability assessment. Results showed that 2.1% of Oman’s land shows strong potential for sustainable urban development. Specifically, three locations stand out with the highest occurring along the southern section of the Arabian Sea between Al Jazir and Ad-Duqum. The other two locations occur at Salalah in the south and Sohar in the north. The promising locations occur proximate to major harbors and can benefit from existing infrastructure, including airports, highways, educational and medical services. Suggested locations also align well with earlier relevant studies. This study demonstrates the capabilities of integrating remotely sensed data with geospatial analysis in urban planning and development. Results are expected to help policymakers and planners to prioritize national-scale urban development. Full article