Search Results (172)

Background: Gum chewing is a common habit among young adults, often promoted for its oral health and psychological benefits. However, as a repetitive and non-functional activity, it is also considered a potential risk factor for temporomandibular disorder (TMD), particularly when practiced chronically. The aim of this study was to evaluate whether excessive gum chewing is associated with a higher prevalence of TMD among young adults presumed to be under elevated academic stress based on their demographic characteristics. Methods: Participants were examined in Krakow, Poland, using the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) protocol. Participants completed a structured questionnaire assessing gum-chewing frequency, duration, and chronicity. Associations between chewing behaviors and TMD presence were analyzed using univariate logistic regression (α = 0.05). Results: This study included young adults 66 participants aged 19–30. TMD was diagnosed in 55 participants (83.3%), including muscular disorders (n = 9; 16.4%), articular disorders (n = 10; 18.2%), and combined muscular–articular disorders (n = 38; 57.6%). More than 70% of participants reported chewing gum for over five years. No statistically significant associations were found between TMD occurrence and the frequency, duration, or chronicity of gum chewing (p > 0.05). Conclusions: These findings suggest that, in the absence of other contributing factors, gum chewing may not independently contribute to TMD development. The elevated TMD prevalence may reflect confounding variables such as high academic stress, narrow age distribution, or female predominance. However, the limited sample size limits statistical power, particularly for detecting subtle effects potentially distorted by other variables. Additionally, the cross-sectional nature of this study precludes causal interpretation. Further studies in larger and more heterogeneous populations are recommended. Full article

This study is a comprehensive experimental and computational investigation into high-resolution laser beam diagnostics, combining classical statistical techniques, numerical image processing, and machine learning-based predictive modeling. A dataset of 50 sequential beam profile images was collected from a femtosecond fiber laser operating at a central wavelength of 780 nm with a pulse duration of approximately 125 fs. These images were analyzed to extract spatial and temporal beam characteristics, including centroid displacement, Full Width at Half Maximum (FWHM), ellipticity ratio, and an asymmetry index. All parameters were derived using intensity-weighted algorithms and directional cross-sectional analysis to ensure accurate and consistent quantification of the beam’s dynamic behavior. Linear regression models were applied to horizontal and vertical intensity distributions to assess long-term beam stability. The resulting predictive trends revealed a systematic drift in beam centroid position, most notably along the vertical axis, and a gradual broadening of the horizontal FWHM. The modeling further showed that vertical intensity increased over time while horizontal intensity displayed a slight decline, reinforcing the presence of axis-specific fluctuations. These effects are attributed to minor optical misalignments or thermally induced variations in the beam path. By integrating deterministic analysis with data-driven forecasting, this methodology offers a robust framework for real-time beam quality evaluation. It enhances sensitivity to subtle distortions and supports the future development of automated, self-correcting laser systems. The results underscore the critical role of continuous, high-resolution monitoring in maintaining beam stability and alignment precision in femtosecond laser applications. Full article

In this study, a conceptual turbine blade model with internal cooling channels was designed and fabricated using the selective laser melting (SLM) process. The optimal manufacturing orientation was evaluated through simulations, and the results indicated that vertical orientation yielded the best outcomes, minimizing support material usage and distortion despite increased manufacturing time. Two configurations were produced, namely, an entire-turbine blade model and a cross-sectional model. Non-destructive analyses, including 3D laser scanning for dimensional accuracy, surface roughness measurements, and liquid penetrant testing, were conducted. Visual inspection revealed manufacturing limitations, particularly in the cooling channels at the leading and trailing edges. The trailing edge was too thin to accommodate the 0.5 mm channel diameter, and the channels in the leading edge were undersized and potentially clogged with unmelted powder. The dimensional deviations were within the acceptable limits for the SLM-fabricated metal parts. The surface roughness measurements were aligned with the literature values for metal additive manufacturing. Liquid penetrant testing confirmed the absence of cracks, pores, and lack-of-fusion defects. The SLM is a viable manufacturing process for turbine blades with internal cooling channels; however, significant attention should be paid to the design of additive manufacturing conditions to obtain the best results after manufacturing. Full article

By way of studying the difference of the proton and neutron distributions in isotopes, isotones and isobars, we used the results of theoretical calculations obtained from the scattering of protons and electrons on nuclei. To calculate the differential cross section of proton scattering, an expression was obtained for the distorted-wave formfactor of the nucleus, which, using the mathematical method proposed by us, is expressed through the plane-wave Born formfactor. In addition, using the data for elastic scattering of electrons on nuclei, the average characteristic parameters of ${}_{20}{}^{40}Ca, {}_{20}{}^{48}Ca$, ${}_{24}{}^{52}Cr$, ${}_{24}{}^{54}Cr$, ${}_{26}{}^{54}Fe$, ${}_{28}{}^{58}Ni, {}_{28}{}^{60}Ni$ nuclei were determined. In this work, for calculating the differential cross section of the elastic scattering of electrons on spherical nuclei, the Fermi function was chosen as a trial function of the proton density distribution. In the calculations, the pole method was used to solve the Born integral of the target nucleus formfactor. Based on an analysis of the calculations of the differential cross section of the elastic scattering of electrons and the calculations of the differential cross section of the scattering of protons on the same nuclei, the main patterns of behavior of the general characteristics of nuclei, such as the root mean square radius (RMS), diffuseness, and the isotopic and isotonic shifts of parameters, were determined. For the ${}_{20}{}^{48}Ca$ nucleus, the radial dependence of the nucleon density distribution on the center of the nucleus, as well as the ratio of proton to neutron densities, have been studied. Changes in the distribution of densities of protons and neutrons with the addition of two neutrons to nucleus ${}_{24}{}^{52}Cr$ as well as changes in the distributions of densities of protons and neutrons when two neutrons are replaced by protons in isobars ${}_{26}{}^{54}Fe-{}_{24}{}^{54}Cr$ have been studied. The results of changes in the distribution of densities of protons and neutrons were justified on the basis of the shell model of the nucleus, using characteristic parameters determined for these nuclei from elastic electron scattering. A joint analysis of experimental work on the elastic scattering of electrons and protons on spherical nuclei leads to the conclusion that the distribution patterns of protons and neutrons differ from each other. In particular, this follows from calculations of the RMS of proton, neutron and nucleon distributions. Full article

This paper presents an experimental and numerical investigation of the axial compression behavior of perforated cold-formed steel upright profiles commonly used in pallet racking systems. The primary objective is to examine how slenderness influences the failure modes and load-bearing capacity of these structural elements. Three column lengths, representative of typical vertical spacing in industrial rack systems, were tested under pin-ended boundary conditions. All specimens were fabricated from 2 mm thick S355 steel sheets, incorporating web perforations and a central longitudinal stiffener. Experimental results highlighted three distinct failure mechanisms dependent on slenderness: local buckling for short columns (SS-340), combined distortional–flexural buckling for medium-length columns (MS-990), and global flexural buckling for slender columns (TS-1990). Finite Element Method (FEM) models developed using ANSYS Workbench 2021 R1 software accurately replicated the observed deformation patterns, stress concentrations, and load–displacement curves, with numerical results differing by less than 5% from experimental peak loads. Analytical evaluations performed using the Effective Width Method (EWM) and Direct Strength Method (DSM), following EN 1993-1-3 and AISI S100 specifications, indicated that EWM tends to underestimate the ultimate strength by up to 15%, whereas DSM provided results within 2–7% of experimental values, especially when the entire net cross-sectional area was considered fully effective. The originality of the study is the comprehensive evaluation of full-scale, perforated, stiffened cold-formed steel uprights, supported by robust experimental validation and detailed comparative analyses between FEM, EWM, and DSM methodologies. Findings demonstrate that DSM can be reliably applied to perforated sections with moderate slenderness and adequate web stiffening, without requiring further local reduction in the net cross-sectional area. Full article

In recent years, synthetic aperture radar (SAR) technology has been increasingly explored for automotive applications. However, automotive SAR images generated via matched filter (MF) often exhibit challenges such as noisy backgrounds, sidelobe artifacts, and limited resolution. Sparse regularization methods have the potential to enhance image quality. Nevertheless, conventional unweighted ${\mathcal{l}}_1$ regularization methods struggle to address cases with radar cross section (RCS) distributed over a wide dynamic range, often resulting in insufficient sidelobe suppression, amplitude distortion, and inconsistent super-resolution performance. In this paper, we propose a novel reweighted regularization method, termed multi-segment-reweighted regularization (MSR), for automotive SAR image restoration. By introducing a novel weighting scheme, MSR localizes the global scattering point enhancement problem to the mainlobe scale, effectively mitigating sidelobe interference. This localization ensures consistent enhancement capability independent of RCS variations. Furthermore, MSR employs multi-segment regularization to constrain amplitude within the mainlobes, preserving the characteristics of the original response. Correspondingly, a new thresholding function, named Thinner Response Undistorted THresholding (TRUTH), is introduced. An iterative algorithm for enhancing automotive SAR images using MSR is also presented. Real data experiments validate the feasibility and effectiveness of the proposed method. Full article

Background/Objectives: Helicobacter pylori (H. pylori) is a significant global health issue causing chronic gastritis, peptic ulcers, and gastric malignancies. Unfortunately, many, particularly in the Middle East, continue to exhibit alarming rates of prevalence. This study aimed to elucidate local epidemiological patterns of H. pylori and examine its histopathological impact on the gastric mucosa. Methods: This retrospective-cross-sectional study included 805 symptomatic adults (329 males, 476 females) who underwent endoscopic evaluation at King Salman Hospital, Ha’il, Saudi Arabia. Biopsies from the antrum and body were processed using routine formalin fixation and paraffin embedding. Staining with hematoxylin–eosin (H&E) and Giemsa permitted assessment of chronic gastritis and detection of H. pylori. Data were evaluated by IBM SPSS (version 23, IBM Corp., Armonk, NY) for associations among infection, histopathology, and patient characteristics. Results: A total of 727 (90.3%) were H. pylori-positive with marginally higher rates in females (91.2%) than males (89.0%). Infection spanned all age groups, reaching 100% in males aged 60–80 years. Overall chronic GI complications were identified in 726 (99.9%), with chronic gastritis being the most profound histopathologically (19.3%). Lymphoid aggregates in 93.0% biopsies reflected a pronounced immune response. Advanced lesions, including metaplasia (0.8%), atrophy (0.3%), and lymphoma (0.1%), were uncommon, though indicative of potential malignant progression. Despite both sexes exhibiting universal symptoms of gastritis, dyspepsia, and heartburn, there were no statistically significant gender-based differences (p > 0.05); specifically, post-H. pylori signs such as vomiting, nausea, weight loss, bleeding or hematemesis occurred equally in all. Histopathology consistently revealed chronic active gastritis with glandular distortion, lymphoplasmacytic infiltration, and occasional mucosal erosions. Giemsa staining further confirmed abundant spiral shapes underscoring a high bacterial load. Conclusion: These findings highlight the age-specific persistently elevating rates of H. pylori significantly associated with chronic gastric inflammatory complications. Although advanced gastric lesions remain rare, reflecting regional epidemiology, early screening, and sleeve treatment efforts, the potential for malignant transformation makes it imperative for continued vigorous eradication, therapy, and vigilant follow-up to avert severe disease outcomes. Full article

Digital Surface Models (DSMs) have a wide range of applications, including the spatial and temporal analysis of human habitation. Traditionally, DSMs are generated by rasterizing Light Detection and Ranging (LiDAR) point clouds. While LiDAR provides high-resolution details, the acquisition of required data is logistically challenging and costly, leading to limited spatial coverage and temporal frequency. Satellite imagery, such as Synthetic Aperture Radar (SAR), contains information on surface height variations in the scene within the reflected signal. Transforming satellite imagery data into a global DSM is challenging but would be of great value if those challenges were overcome. This study explores the application of a U-Net architecture to generate DSMs by coupling Sentinel-1 SAR and Sentinel-2 optical imagery. The model is trained on surface height data from multiple U.S. cities to produce a normalized DSM (NDSM) and assess its ability to generalize inferences for cities outside the training dataset. The analysis of the results shows that the model performs moderately well when inferring test cities but its performance remains well below that of the training cities. Further examination, through the comparison of height distributions and cross-sectional analysis, reveals that estimation bias is influenced by the input image resolution and the presence of geometric distortion within the SAR image. These findings highlight the need for refinement in preprocessing techniques as well as advanced training approaches and model architecture that can better handle the complexities of urban landscapes encoded in satellite imagery. Full article

The landing gear of an aircraft plays a crucial role in ensuring the safe takeoff and landing of the aircraft. Several defects in landing gear press molding may occur, including cross-section distortion, wall thickness thinning, and the springback phenomenon. These defects can significantly impact the quality of the molded product. This study employs a combination of finite element simulation and ML models to predict the springback angle of 7075 high-strength aluminum alloy pipes. The ABAQUS 2021 software was used to simulate the deformation behavior in the bending process based on the large deformation elastoplasticity theory. By utilizing the entropy method and analysis of variance (ANOVA), the significant factors affecting the forming quality were determined in the following order: pipe diameter > mandrel and pipe clearance > material properties > wall thickness > speed. The training set was augmented to improve the model generalization ability to build a multi-stage prediction model based on Lasso regression. The results show that the R² score of the ridge model reaches 0.9669, which is significantly better than other common machine learning methods. Finally, the model was applied to a real experimental dataset example through a transfer learning technique, showing obvious improvement compared with the control group. This study effectively predicts the springback angle of large-diameter thin-walled pipes and significantly improves the molding quality of bent fittings. Full article

Background and Aims: Bariatric surgery is an effective treatment for weight loss and improvement of associated comorbidities. However, some factors could negatively influence favorable results after surgery. This paper aimed to identify whether there is an association between the predominant domain of eating behavior and perception of distortion of and satisfaction with body image in people who underwent bariatric surgery in Brazil. Materials and Methods: To this end, we carried out a cross-sectional, quantitative, analytical study with a convenience sample and with data collected through online questionnaires available on Google Forms™. Results: There was a higher frequency for females. Cognitive restriction was the predominant eating behavior domain. We found an association between body image distortion and cognitive restriction (p = 0.001) and between body image distortion and emotional eating (p = 0.001). Conclusions: The results elucidated the importance of researching eating behavior and body image in people who have had bariatric surgery. New prospective studies should be encouraged to understand the cause–effect relationship between eating behavior and body image. Full article

An electromagnetic (EM) absorber-embedded Ka-band double-layer tapered slot antenna (DLTSA) is proposed in this work. The EM absorber is placed on both sides of the tapered radiating slots as a means of achieving the reduced monostatic radar cross section (RCS) at the X-band. A conventional tapered slot antenna (TSA) with EM absorbers at the same position suffers from the distorted current distribution from the feedline to the radiating slots and causes a degraded radiation performance with a tilted beam. In contrast, the DLTSA with EM absorbers maintains the impedance and radiation characteristics of the antenna without the EM absorbers, while achieving the reduced monostatic RCS for the cross-polarized incident wave. The functionality of the reduced RCS is verified with the 4-by-4 DLTSA array design. The 4-by-4 array prototype with FGM-125 EM absorbers is matched at the Ka-band with a 14.7 dBi boresight gain at 35 GHz. The monostatic RCS is measured in an indoor environment, showing 6.5 dB monostatic RCS reduction at the X-band on average, verifying the computed expectations. This work validates the possible use of EM absorbers at the front side of a missile seeker composed of end-fire radiating elements. Full article

Background/Objectives: Although child-to-parent violence (CPV), peer violence (PV), and dating violence (DV) share risk factors and tend to co-occur, little is known about the common and differential mechanisms involved in the development of these types of youth violence. This study aims to (1) analyze the relationship between youth violence (CPV, PV, and DV) and perceived parental warmth and moral disengagement mechanisms and (2) explore the mediating role of moral disengagement mechanisms in the relationship between the lack of perceived parental warmth and youth violence. Methods: A cross-sectional population-based survey study was conducted. The sample consisted of 2124 Spanish adolescents (57.9% girls) aged between 13 and 17 years from educational centers. Results: The lack of perceived parental warmth (parental criticism-rejection in particular) is a common risk factor for all three types of violence and, more relevantly, is related to youth violence through moral disengagement mechanisms, highlighting a differential contribution of these mechanisms according to the type of violence. In particular, advantageous comparison and attribution of blame are specific mediators of CPV, and moral justification and distortion of consequences are specific to PV, whereas euphemistic language seems to be a common mediator of PV and DV. Conclusions: This study suggests that adolescents who perceive a lack of parental warmth are more likely to develop different dysfunctional cognitive mechanisms, which in turn are related to different types of youth violence. It would be important to promote warm parenting practices and address the cognitive mechanisms underlying youth violence. Full article

This paper presents a novel methodology to generate Digital Elevation Models (DEMs) in flat areas, incorporating river channels from relatively coarse initial data. The technique primarily utilizes filtered dense point clouds derived from SfM-MVS (Structure from Motion-Multi-View Stereo) photogrammetry of available crewed aerial imagery datasets. The methodology operates under the assumption that the aerial survey was carried out during low-flow or drought conditions so that the dry (or almost dry) riverbed is detected, although in an imprecise way. Direct interpolation of the detected elevation points yields unacceptable river channel bottom profiles (often exhibiting unrealistic artifacts) and even distorts the floodplain. In our Fluvial Domain Method, channel bottoms are represented like “highways”, perhaps overlooking their (unknown) detailed morphology but gaining in general topographic consistency. For instance, we observed an 11.7% discrepancy in the river channel long profile (with respect to the measured cross-sections) and a 0.38 m RMSE in the floodplain (with respect to the GNSS-RTK measurements). Unlike conventional methods that utilize active sensors (satellite and airborne LiDAR) or classic topographic surveys—each with precision, cost, or labor limitations—the proposed approach offers a more accessible, cost-effective, and flexible solution that is particularly well suited to cases with scarce base information and financial resources. However, the method’s performance is inherently limited by the quality of input data and the simplification of complex channel morphologies; it is most suitable for cases where high-resolution geomorphological detail is not critical or where direct data acquisition is not feasible. The resulting DEM, incorporating a generalized channel representation, is well suited for flood hazard modeling. A case study of the Ranchería river delta in the Northern Colombian Caribbean demonstrates the methodology. Full article

Background: Anxiety disorders have been rising globally, particularly among adolescents and women. However, the relationship between diet, psychological traits, and anxiety levels in athletes remains underexplored. Objectives: This study aimed to analyze the nutritional and psychological differences between athletes with varying anxiety levels, hypothesizing that higher anxiety correlates with unhealthier dietary habits, greater body distortion, and less adaptive psychological profiles. Methods: A total of 58 athletes (23 women, 35 men), aged 18 to 45 years (mean age = 30.2 years), participated in this cross-sectional study. Data were collected using validated online questionnaires, including the Big Five Inventory, Spielberger State–Trait Anxiety Inventory (STAI), Acceptance and Action Questionnaire-II (AAQ-II), UCLA Loneliness Scale, and Eating Disorder Inventory (EDI), as well as surveys assessing nutritional habits and physical activity levels. Statistical analyses were conducted using SPSS (v24.0), with independent t-tests to compare differences between higher and lower anxiety groups (p < 0.05). Results: It has beenindicated that higher anxiety was associated with greater neuroticism, lower psychological flexibility, and higher eating disorder symptomatology, while better sleep quality and psychological profiles correlated with lower anxiety levels. Additionally, athletes who cooked their own meals exhibited higher anxiety, whereas greater water intake and whole grain consumption were linked to lower anxiety. More frequent and intense training, particularly weight training, was also associated with reduced anxiety. Conclusion: This study concludes that anxiety in athletes is influenced by multiple lifestyle factors, including sleep quality, dietary habits, psychological traits, and exercise patterns. These findings emphasize the need for holistic approaches integrating nutrition, psychological interventions, and structured physical training to manage anxiety in athletes. Full article