Search Results (130)

Background/Aim: Social networks have transformed the traditional dynamics of identity construction in adolescence, allowing users to select content and interact with others who share similar views, thereby reinforcing a sense of belonging to homogeneous groups. Given the growing influence of digital interaction on social identity among youth, psychometrically sound instruments are needed to measure this process. This study aimed to evaluate the psychometric properties of both the 9-item (IBRS-9) and 6-item (IBRS-6) versions of the Identity Bubble Reinforcement Scale in a large sample of Chilean adolescent students. Methods: A cross-sectional design was used with 4096 participants (50.8% male, 47.8% female, 1.4% other; M = 15.82, SD = 1.30) from 41 secondary schools across Chile. Confirmatory factor analyses (CFAs) tested factorial validity, and internal consistency and external criterion validity were examined. Measurement invariance was assessed across sex, social media use, internet use, and age. Analyses were conducted using the WLSMV (Weighted Least Squares Mean and Variance Adjusted), and model evaluation was based on conventional goodness-of-fit indices. Results: CFAs supported the factorial validity of both IBRS versions, showing reliability and external criterion validity. Model fit indices indicated good fit for both scales. Invariance analyses confirmed factorial stability up to the strict level across all subgroups, indicating consistent psychometric performance. Conclusions: The IBRS-9 and IBRS-6 are valid and reliable instruments for assessing identity bubble reinforcement among Chilean adolescents, providing evidence of factorial stability and applicability for research and educational and psychosocial interventions. Their validated structure provides a consistent basis for examining social identity processes related to digital interaction. Full article

Background/Objectives: The marginal adaptation of CAD/CAM restorations remains a key determinant of long-term clinical success, particularly in minimally invasive preparations. This in vitro study evaluated and compared the marginal gap of three CAD/CAM restorative materials—Cerasmart, G-CAM, and IPS Empress CAD—using standardized preparation and SEM measurement protocols. Methods: A total of 18 crowns were fabricated, of which 9 presented margins sufficiently interpretable under SEM and were included in the pooled quantitative analysis (n = 362 measurement points). Marginal gaps were recorded at 45×, 100× and 450× magnification using a Jeol JSM 25S scanning electron microscope. Normality and variance homogeneity were verified prior to parametric testing. Results: When pooled per material group, the mean ± SD marginal gap values were 18.53 ± 14.15 µm for Cerasmart, 21.60 ± 14.89 µm for G-CAM, and 47.09 ± 16.93 µm for IPS Empress CAD. All values fell below the contemporary clinical threshold of <70 µm for adhesive cementation. Pairwise comparison showed a large difference between IPS Empress CAD and the two resin-based materials, whereas the difference between Cerasmart and G-CAM was small. Conclusions: Hybrid and resin nano-ceramic CAD/CAM materials demonstrated narrower marginal gaps compared with the glass ceramic tested, likely due to their lower elastic modulus and greater seating accommodation during cementation. Within the limits of this in vitro design, all materials exhibited marginal adaptation consistent with current clinical acceptability criteria. Full article

Body measurements are used regularly to describe phenotypes or the weight of animals. However, little data describe the age effect on the different measurements. In the present paper, 477 Bactrian camels (7–180 months old) were measured (length of the head, length and circumference of the neck, height at the withers, girth circumference, length of the front leg, and length of the body), and their growth was modeled by comparing different equations, the most convenient being the beta growth equation. In addition, the differences in body measurements of adult Bactrian camels between farms were tested by variance analysis, and multivariate analyses were used for identifying homogeneous clusters of camels according to their body measurements. The sampled animals were from different regions of the country. The significant relationships between cluster and region support the idea of racial differentiation. Body condition scoring is widely used in farm animals as an indicator of their feeding, health, and welfare status. If a body condition score is available for dromedaries, there is no specific grid for the Bactrian camel. Starting from typical examples taken from photos in different conditions, including extreme ones, a representation of a scoring system of 6 points from very emaciated (score 0) to overweight Bactrian camel (score 5) was proposed in the form of drawings from the right side, back, and three-quarter rear. To complete the drawings, a descriptive grid was built as a base for training stakeholders in relation to Bactrian camel farm management. However, the seasonal change in the fleece abundance, the variability of the humps’ shape, and the presence of crossbreeding with dromedary camels require adapting the scoring accordingly. Full article

This study quantified mercury (Hg) levels in the body hair of domestic and wild animals in four Brazilian states, Paraná, Mato Grosso do Sul, Goiás, and Minas Gerais, by analyzing 169 samples from sows, piglets, free-range pigs, and wild animals. The highest mean Hg concentration (274.93 ± 48.14 µg/kg) was found in wild animals in the Pantanal (MSSilvestre, Mato Grosso do Sul), followed by Minas Gerais (245.09 ± 40.27 µg/kg) and Paraná (193.0 ± 42.45 µg/kg). Levels at the GO, MGM, MSLiv, and PRV sites were significantly lower (p ≤ 0.05), according to the Scott–Knott test. Statistical analysis using ANOVA indicated significant variation in Hg levels between locations (F = 2.36; p ≤ 0.05), with homogeneity of variance (Levene’s test, p = 0.1772). Animals raised in confinement had lower levels than wild animals, which, due to extensive movement and contact with diverse environments, exhibited greater bioaccumulation. Lactating sows showed greater sensitivity than piglets, demonstrating an effect of animal category on metal absorption. The main sources of mercury are anthropogenic activities, such as mining and industrial processes, responsible for the environmental release of the metal. Although the detected levels do not pose an immediate risk to animal health or meat quality, they highlight the need for continuous monitoring, given mercury’s ability to bioaccumulate and affect ecosystems and food security. This work contributes to the understanding of environmental exposure to mercury in Brazil, reinforcing the urgency of effective mitigation strategies to preserve biodiversity and public health. Full article

Background/Objectives: Dental enamel constitutes the first barrier of defense against external factors that constantly generate wear and damage. This study aimed to evaluate in vitro the abrasion and roughness of dental enamel using toothpaste with and without activated charcoal and to analyze this under scanning electron microscopy (SEM). Materials and methods: The research design was experimental; 10 enamel blocks were randomly assigned to each group to perform brushing cycles with soft- and medium-filament brushes with two types of toothpaste, one with activated charcoal and one without activated charcoal. A pumice stone with etching acid was used as the positive control and artificial saliva served as the negative control; both were analyzed separately. Roughness was evaluated using a roughness meter and abrasion with an analytical balance. The surface of the enamel blocks of each group was randomly analyzed under an SEM. Statistical analysis was performed using the Shapiro–Wilk test and the homogeneity of variances with Bartlett’s test. Student’s t-test (two-tailed) was applied to compare tooth enamel roughness and abrasion. Results: Both enamel roughness (p = 0.0016) and abrasion (p = 0.0001) were significantly higher in the groups using activated charcoal paste and medium-filament brushes. SEM observation revealed greater alteration on the surface of the enamel subjected to brushing cycles with activated charcoal paste and a medium-filament brush. Conclusions: The in vitro study showed that the use of toothpaste with activated charcoal increases the roughness and abrasion of tooth enamel, especially when the medium-filament brush is used. Full article

Practical problems often drive the development of new statistical methods by presenting real-world challenges. Testing the homogeneity of n independent Poisson means when only one observation per population is available is considered in this paper. This scenario is common in fields where limited data from multiple sources must be analyzed to determine whether different groups share the same underlying event rate or mean. These settings often exhibit underlying structural or spatial symmetries that influence statistical behavior. Traditional methods that rely on large sample sizes are not applicable. Hence, it is crucial to develop techniques tailored to the constraints of single observations. Under the null hypothesis, with large n and a fixed common mean $\lambda$, the likelihood ratio test statistic (LRTS) is shown to be asymptotically normally distributed, with the mean and variance being approximated by a truncation method and a parametric bootstrap method. Moreover, with fixed n and large $\lambda$, under the null hypothesis, the LRTS is shown to be asymptotically distributed as a chi-square with $n-1$ degrees of freedom. The Bartlett correction method is applied to improve the accuracy of the asymptotic distribution of the LRTS. We highlight the practical relevance of the proposed method through applications to wildfire and radioactive event data, where correlated observations and sparse sampling are common. Simulation studies further demonstrate the accuracy and robustness of the test under various scenarios, making it well-suited for modern applications in environmental science and risk assessment. Full article

Background: Enamel surface roughness after bracket debonding is an important issue due to its impact on plaque accumulation and the potential development of carious lesions. This in vitro study aimed to assess enamel roughness after the removal of metallic and sapphire brackets and the effect of a remineralization treatment. Methods: Two hundred extracted human permanent teeth with healthy enamel were randomly distributed into two groups (n = 100) and bonded with either metallic or sapphire brackets using the same adhesive (3M™ Transbond™ XT (St. Paul, MN, USA), Minnesota Mining and Manufacturing Company, MN, USA). The enamel surface roughness was measured before bonding, after debonding, and after remineralization using SEM and a TR200 roughness (SaluTron GmbH, Frechen, Germany) tester. The parameter Ra was used to quantify the surface roughness. One-way ANOVA, the normality test, variance homogeneity, and the Bonferroni post hoc test were used to analyze the data. Results: Debonding significantly increased the enamel surface roughness in both groups. The sapphire bracket group presented significantly higher mean Ra values post debonding (4.14 ± 0.36 µm) compared to the metallic group (2.56 ± 0.52 µm). Remineralization led to a decrease in surface roughness in both groups, though not to baseline levels. The changes were statistically significant (p < 0.01), with a power of the test of 1.0. Conclusions: The bracket material significantly affects enamel surface roughness after orthodontic debonding. Sapphire brackets produced greater surface irregularities than metallic ones. Remineralization partially reduced roughness in both groups, with the final values in the metallic group being closer to baseline levels. Crucially, these values remained far above the clinical threshold for plaque retention, highlighting the need for improved debonding techniques. Full article

The multi-factorial hypothesis of quantitative trait inheritance originated from Nilson’s wheat hybridization experiments. It takes unit traits as the object and is based on the binomial distribution mathematically. Due to the requirement of the same distribution, it cannot include genes of other distributions. This is its limitation. Moreover, it does not incorporate the environmental effects that constitute the phenotype, so it is not comprehensive enough. This article started from the overallness of quantitative traits, was based on the central limit theorem, and was analyzed from both the genotype and the environment and proposed the assumption on the inheritance of dual multi-factors and tri-normal distributions of quantitative traits. This genetic model was tested with practical examples, and three inferences were made. Method and Results: Firstly, the overallness of quantitative traits was discussed, thus the above assumption was proposed. Next, using many examples of normal distribution of quantitative characters in the homogeneous populations, the research on the identification of the environments without GEI was carried out. Then, the examples of normal distribution of the same quantitative characters in the homogeneous populations and in the segregated populations of the same family were used. By means of normal distribution of quantitative characters in the homogeneous populations, it was indicated that the test locations were the environments without GEI. By utilizing the properties of normal distribution and variance, it was proven that normal distribution of phenotypic value for quantitative traits in a segregated population was formed by adding normal distribution of genotypic value and environmental effect, which enables the genetic model to be tested in practice. Three types of normal distribution of quantitative traits were inferred, indicating that the quantitative characters of a considerable number of organisms in nature obey a normal distribution, expressing continuous variation. Full article

The identification of Aspergillus flavus (A. flavus), a fungus known for producing aflatoxins, poses a taxonomic challenge due to its morphological plasticity and similarity to closely related species. This article proposes a computational approach for its characterization across four culture media, using ultraviolet (UV) radiation imaging and radiomic analysis. Images were acquired with a camera controlled by a Raspberry Pi and processed to extract 408 radiomic features (102 per color channel and grayscale). Shapiro–Wilk and Levene’s tests were applied to verify normality and homogeneity of variances as prerequisites for an analysis of variance (ANOVA). Nine features showed statistically significant differences and, together with the culture medium type as a categorical variable, were used in a supervised classification stage with cross-validation. Classification using Support Vector Machines (SVM) achieved 97% accuracy on the test set. The results showed that the morphology of A. flavus varies significantly depending on the medium under UV radiation, with malt extract agar being the most discriminative. This non-invasive and low-cost approach demonstrates the potential of radiomics combined with machine learning to capture morphological patterns useful in the differentiation of fungi with optical response under UV radiation. Full article

Objective: The prevalence and severity of obstructive sleep apnea (OSA) increase with age, suggesting that age-related factors are etiological factors for OSA in older adults. In addition to anatomic contractions of the upper respiratory tract, such as those caused by obesity and retrognathia, sleep is impaired in older OSA patients due to aging. Although aging has long been associated with structural changes in the upper airway potential, specific age-related anatomical differences in patients with OSA are not established. This study aimed to examine age-related morphological differences in OSA patients, particularly in older adults. Methods: This study was designed as a retrospective cross-sectional study conducted at the Center for Dental Sleep Medicine, Osaka Dental University, between May 2017 and September 2022. From an initial cohort of 1032 patients, 183 male participants were included after applying strict inclusion and exclusion criteria. Patients were classified into two age groups: middle age (40–60 years) and older age (≥65 years). Polysomnographic parameters; body mass index (BMI); airway space (AS) obtained from cephalometric radiographs; length of the soft palate (PNS-P); SNB angle, as an indicator of mandibular position; and the position of the hyoid bone (MP-H) were compared between the groups. Statistical analysis included Levene’s test for homogeneity of variances, independent sample t-tests for group comparisons, and multiple regression analyses to identify independent predictors of AHI. This study was conducted with the approval of the Ethics Committee of Osaka Dental University (No. 111047). Results: Older patients showed significantly lower REM sleep percentage (13.5 ± 1.31% vs. 16.4 ± 0.59%, p = 0.047), significantly lower BMI (23.6 ± 0.45 kg/m² vs. 24.6 ± 0.29 kg/m², p = 0.049), and significantly larger AS (15.8 ± 0.52 mm vs. 12.0 ± 0.27 mm, p = 0.000) compared to middle-aged patients. Furthermore, in the middle-aged group, BMI (β = 0.40, 95% CI: 1.46 to 3.41, p < 0.001), SNB (β = −0.18, 95% CI: −1.75 to −0.09, p = 0.030), and MP-H (β = 0.19, 95% CI: 0.10 to 1.01, p = 0.018) were significant independent predictors of AHI. In the older group, no parameters were significant predictors of AHI. Conclusions: We found that older adult patients had a larger airway diameter and lower REM sleep percentage and BMI than middle-aged patients. Furthermore, regarding factors associated with AHI, which is an indicator of sleep apnea severity, in the middle-aged group, anatomical factors such as BMI, SNA, and MPH contributed significantly, but in the older adult group, anatomical factors were not relevant. The results suggested that anatomical factors alone may not fully explain the pathogenesis of OSA in older patients, highlighting the need for further studies focusing on other age-related factors. Full article

Aluminium metal matrix composites (AMMCs) incorporate aluminium alloys reinforced with fibres (continuous/discontinuous), whiskers, or particulate. These materials were engineered as advanced solutions for demanding sectors including construction, aerospace, automotive, and marine. Micro- and nano-scale reinforcing particles typically enable attainment of exceptional combined properties, including reduced density with ultra-high strength, enhanced fatigue strength, superior creep resistance, high specific strength, and specific stiffness. Microstructural, mechanical, and tribological characterizations were performed, evaluating input parameters like reinforcement weight percentage, applied normal load, sliding speed, and sliding distance. Fabricated nanocomposites underwent tribometer testing to quantify abrasive and erosive wear behaviour. Multiple investigations employed the Taguchi technique with regression modelling. Analysis of variance (ANOVA) assessed the influence of varied test constraints. Applied load constituted the most significant factor affecting the physical/statistical attributes of nanocomposites. Sliding velocity critically governed the coefficient of friction (COF), becoming highly significant for minimizing COF and wear loss. In this review, the reinforcement homogeneity, fractural behaviour, and worn surface morphology of AMMCswere examined. Full article

Background/Objectives: Previous meta-analyses on vitamin D (VitD) supplementation for fall prevention have mixed different populations and doses. This study aimed to evaluate whether VitD supplementation reduces fall risk in community-dwelling adults aged ≥65 years. Methods: Randomized clinical trials (RCTs) including adults ≥65 years living in the community and receiving supplemental VitD were identified through the MEDLINE and EMBASE databases (January 2005–July 2024), and independent reviewers selected studies reporting fall risk, extracted data, and assessed risk of bias. Outcomes were pooled using the inverse variance method. Heterogeneity and publication bias were assessed with I², Egger’s test, and the trim-and-fill method. Results: The analysis dataset was 23,211 participants from 10 RCTs. Most studies had minimal risk of bias. Overall, VitD supplementation was not associated with a reduction in fall risk, as no statistically significant or consistent trend was observed (OR = 0.99; 95%CI: 0.95–1.03; I² = 31%). In women, no significant association was found (OR = 0.97; 95%CI: 0.92–1.02; I² = 31.2%), and in men, no significant association was observed (OR = 1.08; 95%CI: 0.98–1.20; I² = 0%) when analyzed separately. Supplementation with doses ≤1000 IU/day showed no significant association with fall risk (OR = 0.96; 95%CI: 0.90–1.02; I² = 39.5%), as did durations ≤12 months (OR = 0.96; 95%CI: 0.90–1.02; I² = 56.2%) and daily administration (OR = 0.97; 95%CI: 0.92–1.03; I² = 37.2%). Doses >1000 IU/day, intermittent dosing (both OR = 1.02; 95%CI: 0.96–1.09; I² = 0%), and durations >12 months (OR = 1.01; 95%CI: 0.96–1.07; I² = 0%) all showed no significant association. Although evidence of publication bias was detected, adjustment did not alter the results. Conclusions: This meta-analysis shows that VitD supplementation has no effect on the risk of falls in community-dwelling adults ≥65 years, yet its main interest lies in ensuring population homogeneity found in previous analyses of mixed settings. Full article

Background: Chinese Red Steppe cattle (CRS) combine indigenous environmental resilience with moderate dairy performance, whereas Holstein cattle (HOL), despite their high milk yield, suffer reduced genetic diversity and compromised adaptation. A comparative analysis of their population genetic architecture and selection signatures can reveal valuable targets for CRS dairy improvement. Methods: We genotyped 61 CRS and 392 HOL individuals using the Illumina GGP Bovine 100K SNP array and performed stringent quality control. Population structure was assessed via principal component analysis, neighbor-joining trees, and sparse nonnegative matrix factorization. Historical effective population size (Ne) and divergence time were inferred with SMC++. Genome-wide selection scans combined Fixation Index (FST) and Cross-Population Composite Likelihood Ratio test (XP-CLR); overlapping high-confidence regions were annotated and subjected to GO and KEGG enrichment analyses. Results: CRS and HOL were clearly separated along PC1 (explaining 57.48% of variance), with CRS exhibiting high internal homogeneity and weak substructure, versus greater diversity and complex substructure in HOL. SMC++ indicated a split approximately 3500 years ago (700 generations) and a pronounced recent decline in Ne for both breeds. Joint selection mapping identified 767 candidate genes; notably, the ACSM1/2B/3/4 cluster on chromosome 25—key to butanoate metabolism—showed the strongest signal. Enrichment analyses highlighted roles for proteasome function, endoplasmic reticulum stress response, ion homeostasis, and RNA processing in regulating milk fat synthesis and protein secretion. Conclusion: This study delineates the genetic divergence and demographic history of CRS and HOL, and pinpoints core genes and pathways—particularly those governing butanoate metabolism and protein quality control—underlying dairy traits. These findings furnish molecular markers and theoretical guidance for precision breeding and sustainable utilization of Chinese Red Steppe cattle. Full article

Nursing students often face emotional challenges related to death and dying, affecting their psychological well-being, emotional intelligence, and academic success. Cultural and educational factors may influence how they experience and manage these stressors. This study aimed to compare fear of death, emotional intelligence, coping with death, and academic burnout among second-year nursing students in Spain and Portugal to identify cross-cultural differences. A cross-sectional study was conducted among 174 second-year nursing students from the University of Extremadura (Spain) and the University of Évora (Portugal) during the 2023/2024 academic year. The instruments used included the Collett–Lester Brief Fear of Death Scale, the Trait Meta-Mood Scale—24 ítems, the Bugen’s Coping with Death Scale, and the Maslach Burnout Inventory—Student Survey. Descriptive statistics were calculated, and group comparisons were performed using independent samples t-tests and Welch’s t-tests, depending on variance homogeneity. A two-way ANOVA was also conducted to explore interactions between gender and nationality. The Spanish sample comprised 86 women and 21 men, and the Portuguese sample included 58 women and 9 men. The mean age across the sample was 21.5 years (SD = 4.15). No significant differences were observed in fear of death or emotional intelligence between the two groups. However, Portuguese students showed significantly better coping with death, but also higher academic burnout and cynicism. Spanish students reported greater perceived efficacy. Although emotional intelligence and death anxiety were similar, Portuguese students demonstrated stronger coping skills but experienced more burnout. This suggests that coping alone may not buffer academic stress, emphasizing the need for culturally tailored interventions to enhance emotional readiness and reduce burnout. Full article

This in vitro study aims to compare the trueness of digital impressions obtained using two intraoral scanners (IOS) and one photogrammetry device for full-arch implant-supported rehabilitations. According to the Caramês Classification I, three models were produced with Straumann implants arranged in different spatial distributions: Option A with six implants and Options B and C with four implants each. The three models were scanned using a 12-megapixel scanner to create digital master casts. For each reference model, 30 digital impressions were acquired: 10 with the 3Shape Trios 3 intraoral scanner, 10 with the Medit i500 intraoral scanner, and 10 with the PIC Dental photogrammetry device. Trueness was assessed through best-fit superimpositions between the digital master casts and the corresponding virtual models. The Shapiro–Wilk test was applied to assess the normality of the data distribution, and Levene’s test was used to evaluate the homogeneity of variances. The non-parametric Kruskal–Wallis test was employed to compare group differences, with post hoc adjustments made using the Bonferroni correction. A significance threshold of p = 0.05 was adopted for all statistical tests. Statistically significant differences were observed in the root mean square values among the three devices. The Medit i500 demonstrated the highest trueness, with a median (interquartile range) deviation of 24.45 (18.18) µm, whereas the PIC Dental exhibited the lowest trueness, with a median deviation of 49.45 (9.17) µm. Among the implant distribution, the Option C showed the best trueness, with a median deviation of 19.00 (27.83). Considering the results of this in vitro study, intraoral scanners demonstrated comparable trueness, whereas the photogrammetry-based system exhibited lower trueness values. Additionally, a smaller number of implants and reduced inter-implant distances were associated with improved trueness in digital impressions for full-arch implant rehabilitation. Full article