Search Results (8,857)

With the development of polar regions and the deepening utilization of cold region resources, a large number of infrastructure projects are continuously being carried out. The freezing temperature of unsaturated soil is a critical factor governing the freezing depth and stability of foundations in cold regions or seasons. Concurrently, the supercooling state of soil significantly influences the assessment of its phase composition and physico-mechanical properties. This study employed physical experiments, theoretical formulas, and numerical simulations to reveal the influencing factors and underlying mechanisms of supercooling characteristics in unsaturated soils under controlled low-rate continuous cooling conditions. The results demonstrate that a reduced temperature gradient between the sample surface and the ambient environment correlates with a lower supercooling limit temperature and an extended supercooling duration. An excessively high cooling rate suppresses the supercooling phenomenon in the sample core due to boundary effects. In contrast, neither the temperature difference nor the external cooling rate exhibit a negligible influence on the freezing temperature. Analysis of the temperature–time curves reveals that the freezing process of silty clay is more stable, exhibiting fewer stepwise temperature declines during the phase change plateau, whereas mudstone shows heightened sensitivity to variations in the thermal gradient. Compared to conventional thermocouple measurements, the proposed methodology achieves an optimal balance between temporal efficiency and measurement accuracy. It not only enhances experimental controllability and data reliability, but also provides more scientific theoretical support and technical pathways for predicting freezing depth, designing foundation thermal systems, and preventing frozen ground disasters in cold region engineering. Full article

Light regime and growth phase are significant determinants of agro-morphological traits and secondary metabolite accumulation in plants. This study evaluated the effects of two light conditions on agro-morphological and phytochemical traits of two Hypericum perforatum genotypes (Topas and Mariana). Natural daylight and an extended 19 h photoperiod with supplemental white fluorescent light were tested at two growth phases (vegetative versus reproductive (flowering)), based on leaf sampling at the respective phases. Analysis of variance showed significant effects of growth phase, light treatment, and genotype on most traits, with growth phase exerting the most decisive influence (p < 0.01). Significant genotype × growth phase interactions were observed for most traits, whereas genotype × light interactions mainly affected phytochemical parameters. Leaf area, gland number, and gland area increased during the reproductive phase, especially in Topas, and were further enhanced under the 19 h photoperiod. Leaf area increased markedly during the reproductive phase, reaching 118.81 mm² in Topas under the 19 h photoperiod compared with 68.40 mm² under natural light. Prolonged light exposure increased hypericin, pseudo-hypericin, hyperforin, flavonoids, and total phenolics. The highest sum of hypericins (4.67 mg g⁻¹ DW), flavonoids (143.09 mg QE g⁻¹ DW), and phenolics (242.74 mg GA g⁻¹ DW) was observed in the Topas in the reproductive phase under the 19 h photoperiod, whereas hyperforin content peaked in vegetative Mariana (55.65 mg g⁻¹ DW). In contrast, the lowest sum of hypericins (1.80 mg g⁻¹ DW) occurred in vegetative Mariana under natural light, while the minimum flavonoids (74.45 mg QE g⁻¹ DW) and phenolics (133.22 mg GA g⁻¹ DW) contents were recorded in the vegetative Topas under natural light regim, and the lowest hyperforin concentration (19.65 mg g⁻¹ DW) was found in the Mariana genotype under natural light regime and in the reproductive phase. Principal component analysis associated PC1 with agro-morphological traits and hypericin-related metabolites, and PC2 with hyperforin and white gland traits. Heatmap and correlation analyses supported these patterns. Overall, extended photoperiod and growth phase are critical drivers of medicinal compound accumulation in H. perforatum. Full article

Objectives: This study evaluated Quality of Life (QoL) and mental health among nursing technicians in Brazilian Unified Health System (SUS) emergency units, specifically exploring occupational safety and well-being in the post-COVID-19 era. Design: A quantitative, descriptive, exploratory, cross-sectional design was employed. Methods: Data from 146 nursing professionals in Brazilian SUS emergency units were collected remotely during the post-acute pandemic phase (July–Nov 2024). QoL (WHOQOL-BREF) and mental health (HADS) were assessed, followed by descriptive and correlational statistics. Results: The predominantly female, experienced sample showed heterogeneous general QoL but pervasive anxiety, reflecting a sustained psychological burden. Sociodemographic/professional factors had a negligible impact; the emergency environment’s overwhelming influence, intensified by post-pandemic challenges, was key. Psychological distress was strongly negatively correlated with overall QoL and depression in the social domain. Conclusions: The intrinsic nature of emergency work, amplified by persistent psychosocial effects of the global health crisis, drives anxiety and impairs QoL/social relationships. Interventions strengthening QoL, enhancing coping, and adapting work environments to new realities (e.g., loneliness, prolonged mental health impacts) are vital for professional well-being and patient care in this post-pandemic era. Full article

Background: Although blinded independent central review (BICR) can reduce assessment variability, it introduces additional financial and logistical burdens to trial operations. This study analyzed the discrepancy indexes (DIs) to evaluate differences between progression-free survival (PFS) assessments by local investigators (LIs) and BICR in randomized clinical trials (RCTs) of patients with metastatic melanoma. Methods: A comprehensive literature search was conducted on PubMed, Embase, and Cochrane databases up to 30 June 2024. The primary outcome was the DI, which was calculated for each trial as a ratio of the hazard ratios (HR)_BICR by HR_LI. The agreement between PFS HRs was also evaluated using the intraclass correlation coefficient (ICC) and Pearson’s correlation coefficient (r). Results: Twelve studies comprising 4915 patients were included in this study. Of these, 10 (83%) were Phase III, 11 (92%) were cutaneous melanoma, one was uveal, and all identified PFS as the primary endpoint. Most (86%) of the PFS comparisons yielded the same statistical inference by both BICR and LIs. The overall combined DI was calculated at 1.08 (95% CI: 1.01–1.15), indicating a statistically significant, numerically small difference in PFS evaluations driven primarily by the uveal Phase III double-blinded study, while there was a strong overall correlation [(ICC: 0.87, p < 0.001); (r = 0.89, 95% CI 0.67–0.96, p < 0.0001)]. Cutaneous melanoma trials demonstrated strong agreement between BICR and local investigator assessments. Conclusions: In randomized trials of metastatic cutaneous melanoma, LI-assessed PFS closely aligns with BICR and provides equivalent trial-level conclusions in most cases. These findings support the use of LI-assessed PFS as a valid and practical primary endpoint, without routine requirement for BICR. Central review should be reserved for selected scenarios. Full article

Cement is one of the primary construction materials in ground improvement applications that employ the binder stabilization method. Due to the high carbon dioxide emissions in its production, evaluating environmentally friendly alternative binder materials is a popular research topic. Industrial by-products such as fly ash (FA) and ground granulated blast-furnace slag (GGBS) are alternatives to traditional cement, especially in deep soil mixing (DSM) applications, and can enhance sustainability in construction projects. Since these materials are not active when used alone, alkali activation is proposed to modify them as binding agents in ground improvement projects. This study presents the outcomes of a primary laboratory test phase for on-site applications. FA and GGBS precursors supplied by local plants, mixed with soil and activator solutions in applicable ratios, and samples were prepared for laboratory tests. Unconfined compression tests were applied with strain measurements after several curing durations, between 1 and 54 weeks. Average compression strength and modulus of elasticity values were recorded at approximately 12.3 MPa and 11.7 GPa, respectively, in samples with an average dosage. An empirical correlation between the strength and stiffness modulus was found. Strength and stiffness values were comparable to traditional materials, indicating the potential of these industrial by-products when activated under alkali conditions. The carbon footprints of cement and alkali-activated by-products were compared based on calculated CO₂-eq emissions. Full article

Background/Objectives: Osseointegration is essential for the long-term success of dental implants, and radiographic assessment may support the evaluation of peri-implant bone healing. This retrospective study evaluated peri-implant radiographic bone density (PIBD) as a potential indicator of osseointegration in patients who underwent successful implant-prosthetic rehabilitation. Methods: Patients with at least one endosseous dental implant and a minimum of two standardized periapical radiographs—one at placement (T0) and one during follow-up—were included. Digital radiographs were obtained using the paralleling technique and analyzed with ImageJ^®. Normalized bone density values were calculated for predefined areas of interest (AOIs). Marginal Bone Level (MBL) changes were also assessed. Statistical analyses included the Shapiro–Wilk test, Kruskal–Wallis test, and Dunn’s post hoc test with Bonferroni correction. Results: 88 implants in 64 patients were analyzed (198 radiographs; 1299 AOIs measurements). Normalized bone density showed significant temporal changes in several AOIs, mainly from 3 to 12 months, across coronal/middle/apical regions. PIBD decreased by approximately 8% between T0 and 3 months, followed by a significant increase at one year. MBL values were minimal and well below physiologic thresholds throughout follow-up. No significant correlation was found between MBL and normalized bone density. Conclusions: PIBD assessment may be a reliable, non-invasive tool for monitoring osseointegration during follow-up and supporting clinical decision-making in postoperative controls. The temporal pattern observed confirms three radiographic healing phases after implant placement: an initial decrease in PIBD during early remodeling, a subsequent increase reflecting osseointegration, and a final stabilization phase corresponding to tertiary implant stability. Full article

The research on nonaqueous two-phase systems, i.e., ternary nonaqueous systems with a liquid–liquid phase split induced by a solid component, is discussed. Previous scattered reports are reviewed and summarized. The first systematic studies are described in detail. These included qualitative testing of numerous ternary systems (a solid component and two liquid solvents, significantly different in polarity) to determine whether a liquid–liquid phase split occurred. Some correlations between this occurrence and the Hofmeister series were suggested. The liquid–liquid equilibrium was determined experimentally in a few systems, and the problems encountered during this determination are discussed. Possible applications and further topics of investigation are suggested. Full article

Background/Objectives: The clinical superiority of rotating-bearing (RB) versus fixed-bearing (FB) total knee arthroplasty (TKA) remains controversial despite the proposed biomechanical advantages of mobile-bearing designs. Objective gait assessment with inertial measurement units (IMUs) provides a measurable view of functional recovery that may complement patient-reported outcome measures (PROMs). This study compared spatiotemporal gait parameters between FB and RB TKA over 24 months. Methods: This prospective longitudinal comparative study enrolled 57 patients undergoing primary unilateral TKA for end-stage knee osteoarthritis. Spatiotemporal gait parameters (gait velocity, cadence, and stance-phase duration) were measured using wireless IMUs (G-WALK system) at 6, 12, and 24 months post-surgery. WOMAC and the 10-point Geriatric Locomotive Function Scale (GLFS-10P) were assessed at 12 and 24 months. Group, time, and Group × Time effects were analyzed using linear mixed-effects models. Results: Both groups improved during follow-up, with performance largely plateauing between 12 and 24 months. At 24 months, there were no significant differences between groups in gait velocity (FB 1.17 vs. RB 1.16 m/s; p = 0.65), cadence (99.8 vs. 97.4 steps/min; p = 0.72), or stance-phase duration (59.3% vs. 59.0%; p = 0.82). Group × Time interactions were not significant across gait outcomes. WOMAC and GLFS-10P improved similarly in both groups (p > 0.05). Cadence was inversely correlated with the WOMAC function subscale at 24 months (rho = −0.563; p = 0.036). Conclusions: FB and RB bearing designs showed similar objective gait recovery trajectories and PROM improvements through 24 months after primary TKA, suggesting no intermediate-term functional advantage from bearing design. Full article

Health and hygiene are critical components of sustainable travel and tourism development, particularly in the post-emergency phase of the COVID-19 pandemic when traveler confidence is closely tied to the resilience of the destination. This paper examines global health and hygiene conditions using data from the Travel & Tourism Development Index (TTDI) 2024, with a focus on disparities across regions and income groups. Five key indicators—physician density, basic sanitation, basic drinking water, hospital bed density, and communicable disease incidence—are analyzed to assess healthcare infrastructure, accessibility, and public health resilience. By comparing data from 2021 and 2024, the study evaluates changes during and after the peak period of the COVID-19 crisis, highlighting progress and persistent inequalities relevant to sustainable travel and tourism development. Using descriptive statistics and Spearman’s rank correlation analysis, the study also investigates the associations between key health and hygiene indicators, specifically (i) basic sanitation and basic drinking water coverage and (ii) physician density and hospital bed density, at the global, regional, and income group levels. The results reveal pronounced regional and income-related disparities. Europe and Eurasia consistently outperform other regions, with high healthcare capacity and near-universal sanitation and water access, while Sub-Saharan Africa continues to face systemic deficits in all indicators. High-income countries have well-developed healthcare systems, whereas low-income countries struggle with limited physician availability, poor sanitation coverage, and high communicable disease incidence. Associations between key indicators are also evident: countries with strong sanitation infrastructure almost always achieve high drinking water coverage, and those with higher physician density typically maintain higher hospital bed capacity. These findings highlight the uneven pace of global recovery and emphasize that health and hygiene are not only public health priorities but also fundamental drivers of tourism competitiveness. Full article

Siberian sturgeon (Acipenser baerii Brandt, 1869), characterized by its rapid mass accumulation and high survival rate under industrial breeding conditions, is one of the most promising aquacultural species. This research aimed to study the growth and development of farmed Siberian sturgeon (Acipenser baerii Brandt, 1869) to improve breeding programs. This research was conducted at the Federal Research Center for Animal Husbandry named after Academy Member L.K. Ernst and focused on the Lena population broodstock of Siberian sturgeon of the April 2022 generation (n = 98), grown in a recirculating aquaculture system (RAS). The experiment took into account body weight (W, g) and eleven morphological measurements: L—absolute length (cm); LR—fish body length increase (cm/day); l—commercial length (cm); L2—fork length (cm); HL—head length (cm); PV—pectoventral distance (cm); VA—ventroanal distance (cm); pl1—peduncle length (cm); H—body height (cm); h—peduncle height (cm); SC—body thickness (cm); GC—body circumference (cm); and Cc—peduncle circumference (cm). These measurements were taken from the same sample of fish at five different time points, all belonging to the same generation and approximately the same age. Measurements were taken every 3 to 9 months: 1 y (group G1), 1 y. 5 m. (group G2), 2 y. 2 m. (group G3), 2 y. 5 m. (group G4), 3 y. 2 m. (group G5), and 3 y. 5 m. (group G6). To evaluate the rate of growth and development, relative speed of growth (SGR) and relative speed of lengthening (SLR) during the observation period were determined. To characterize the fish’s exterior, we evaluated Fulton’s condition factor (KF) and the leanness index (Q). With increasing age, there was a significant (p < 0.01) decline in both SGR (from 0.454 to 0.065 g%/day) and SLR (from 0.132 to 0.028 cm%/day), which reflects changes in the fish’s physiological processes tied to the transition from the growth phase to the puberty phase. Relatively large variability was observed in body weight (C_v = 19.7–30.4%) compared to morphological measurements (C_v = 5.7–14.9%). Correlations between morphological measurements and the body weight of the fish varied from low to high (r = 0.22–0.97). Equations that allow for very precise (coefficient of determination R² = 0.800–0.933) estimation of the fish’s body weight based on morphological measurements were developed. The most preferable predictors were measurements of H (R² = 0.931), SC (R² = 0.933), and L2 (R² = 0.930). These morphological measurements are promising candidates for future development of contactless live weight detection using computer vision and machine learning algorithms. The study of live weight conjugacy at different ages showed that the best time to use this measurement to select fish for reproduction is at the age of 2 y. 2 m. or older. Acquired data can be used for the development and improvement of programs for the selection and breeding of Siberian sturgeon grown in a recirculating aquaculture system. Full article

The gamma band observed in human electroencephalography (EEG) has been extensively studied. However, recent research has begun distinguishing the potential roles assigned to phase and non-phase modulation within this band. The primary aim of this study is to analyze the potential role of non-phase gamma modulation in a widely used visual task in human subjects. For this purpose, using a 58-channel EEG recording, gamma activity was evaluated during an oddball task. Responses from 21 healthy subjects were recorded at two separate time points, with an average interval of 49.5 ± 48.9 days. Latency, amplitude, and topographic correlation values were calculated to assess the replicability. Furthermore, potential influence of alpha band harmonics on gamma was analyzed. Topographic analyses revealed a strong negative correlation between gamma phase-locked (synchronous) and non-phase-locked (asynchronous) activity, with correlation coefficients of r < −0.9 for both measures. The results observed between the two time points were robust. The harmonic analysis did not show any potential contribution of the alpha band. The separate analysis of phase and non-phase activity has enabled us to identify distinct roles for each. Establishing non-phase activity as a perceptual “anti-binding” mechanism opens new avenues for exploring a previously unaddressed aspect of gamma activity. Full article

Background/Objectives: Chronic hepatitis B (HBV) and C (HCV) remain major public health challenges in Romania despite vaccination and antiviral therapy. Understanding infection patterns in different healthcare settings is essential for targeted elimination strategies. Methods: We conducted the prospective screening phase of the RE-LINK project (January–June 2025) through two nationwide private laboratory networks. Adults undergoing routine testing were screened for HBsAg and anti-HCV. HBsAg-positive samples were further analyzed for HBV DNA, HBeAg, anti-HBe, anti-HDV, and HDV RNA, while anti-HCV-positive cases were tested for HCV RNA. Risk factors were assessed using chi-square and logistic regression analyses. Results: Among 9149 individuals (66.6% women with a median age of 53 years), HBsAg prevalence was 2.9%, and anti-HCV was 1.3%, both increasing significantly with age (p < 0.001). Of all HBsAg-positive individuals, 12.5% had undetectable HBV DNA, 70.4% had low viremia (<2000 IU/mL), and 17.1% had high viral loads. Anti-HDV antibodies were detected in 2.3% of HBsAg-positive subjects, all with detectable HDV RNA (range 1250–680,000 IU/mL). Significant risk factors for HBsAg positivity were male sex, older age, urban residence, physician-indicated testing, neuropsychiatric comorbidity, family or parental hepatitis, and institutional/orphanage care, while HBV vaccination and moderate alcohol use were protective. Anti-HCV positivity correlated with older age, cardiovascular disease, elevated transaminases, transfusions, surgery, and HIV co-infection. Only 20.2% of anti-HCV-positive individuals were viremic. Conclusions: Private-laboratory screening reveals residual low-replicative HBV and declining viremic HCV, while community programs uncover HDV and advanced disease in vulnerable groups. A coordinated approach integrating private, community, and hospital-based pathways can accelerate elimination efforts and ensure that HDV is not overlooked. Full article

Traditional multiple-input multiple-output (MIMO) systems are confronted with significant challenges in realizing ubiquitous connectivity for sixth-generation (6G) networks, particularly in environments characterized by severe signal blockage and dynamic co-mobility. While aerial intelligent reflecting surfaces (AIRS) offer a promising paradigm to address these difficulties, the existing channel models often fail to capture fast channel changes, thereby leading to inefficient phase optimization in time-varying scenarios. To address these limitations, a geometric MIMO channel model is proposed for AIRS-assisted communications. This model comprises an indirect link from the base station (BS) via the AIRS to the receiver (Rx) and a direct BS-Rx link, whose direct propagation environment is rigorously characterized by a one-cylinder model specifically designed to tackle the complexities of dynamic co-mobility and intricate propagation. A joint optimization problem is formulated to maximize the achievable rate by optimizing the transmitted signal’s covariance matrix and the AIRS phase shift. Subsequently, an iterative algorithm employing the projected gradient method (PGM) is proposed for its solution, which is tailored for efficient operation in time-varying environments. Furthermore, expressions for the space–time correlation function and Doppler power spectrum are derived to evaluate the overall channel properties. Significant enhancements in achievable rates are demonstrated by AIRS, with substantial gains being observed even for a small number of reflecting elements. Consequently, crucial guidance for the design of robust AIRS-assisted MIMO systems is provided by these findings, and the broad applicability of the proposed algorithm is thereby confirmed. Full article

Accurate and high-efficiency film metrology remains a key challenge in High-Volume Manufacturing (HVM), where conventional spectroscopic reflectometry and white light interferometry (WLI) are either limited by model dependence or throughput. In this work, we extend the measurable film-thickness range of reflectometry to at least 50 µm through a new model-free algorithm, the Linearized Reflectance Zero-Crossing (LRZ) method. The approach builds upon the previously reported Linearized Reflectance Extrema (LRE) technique but eliminates the sensitivity to spectral sampling and fringe attenuation that degrade performance in the thick-film regime. By linearizing phase response and extracting Zero-Crossing positions in wavenumber space, LRZ provides robust and repeatable thickness estimation without iterative fitting, achieving comparable accuracy with much higher computational efficiency than conventional model-based methods. Validation using more than 80 measurements on alumina films over NiFe substrates shows excellent correlation with WLI (r = 0.97) and low gauge repeatability and reproducibility (GR&R < 3%). Moreover, LRZ achieves an average Move-Acquire-Measure (MAM) time of approximately 2 s, which is about 7 times faster than WLI. The proposed method enables fast, accurate, and model-independent optical metrology for thick films, offering a practical solution for advanced HVM process control. Full article

Background/Objectives: Observational learning enables children to acquire new skills by observing others’ actions. Attention is widely recognized as a key supporting process and consists of multiple components that develop substantially during the early school years. Empirical evidence on the association between specific components of attention and observational learning remains limited. Therefore, this study examined the relationship between the main components of attention and observational learning among early primary school children. Methods: Sixty-eight children, aged 6–8, completed a computerized battery assessing the main components of attention (reaction times, simple and related to a choice; focused attention; short-term span of attention; divided and alternating attention) and an observational learning task where children observed an actor detecting a hidden spatial sequence and then reproduced it across detection phase (DP), exercise phase (EP), and automatization phase (AP). Correlational and regression analyses were conducted, controlling for age and gender. Results: Visual and visual–spatial focused attention emerged as significant predictors of performance during DP and EP, with higher levels of focused attention associated with fewer errors and repetitions. Choice reaction time showed phase-specific associations with error rates during early learning phases, whereas age was primarily related to performance during the AP. Conclusions: Observational learning in early primary school relies on specific components of attention rather than on attention as a unitary construct. Visual and visual–spatial focused attention plays a central role during the acquisition and consolidation of observed sequences, with implications for understanding learning from models and for educational practices based on demonstration. Full article