Search Results (69)

Background: Intensive, prolonged endurance and strength training in apparently healthy young athletes causes many physiologic and structural adjustments in the heart, known as athlete’s heart. The correct distinction between physiological adaptations and pathological changes is crucial for the athlete, therefore screening programs are recommended by medical and sports associations. Nevertheless, a small but not negligible proportion of young competitive athletes die by sudden death. In 25% the cause of sudden cardiac death is genetic. Determining the genetic component is of key importance for distinction between athlete’s heart and cardiomyopathy. Methods: A gene panel next-generation sequencing (NGS) was performed in 41 apparently healthy young athletes without previously known heart disease. Results: Across 174 genes with known associations to different cardiac conditions, we identified nine variants: two pathogenic (P) variants and seven variants of unknown significance (VUSs). For all of them a more detailed follow-up with a cardiologist was advised. Conclusions: The results in our study suggest that targeted sequencing of genes associated with cardiovascular disease is the key that enables correct differentiation between athlete’s heart and cardiomyopathy, leading to fast and accurate clinical intervention where necessary. In this way, initial pathological changes are not confused with physiological ones, which could be fatal for the athlete if they continue with competitive sport. Full article

Background/Objectives: Depression, anxiety disorders, and substance use disorders frequently coexist in clinical settings and are main factors that worsen a patient’s prognosis. However, traditional artificial intelligence-based mental health studies have limitations in capturing the complex symptoms that occur in actual counseling situations by relying on social media data or focusing on binomial classification of single diseases. This study proposes a multi-label classification model that simultaneously detects the coexistence of depression, anxiety, and substance use disorder in actual counseling dialogue texts, and applies the Shapley Additive Explanatory (SHAP) method to explain the clinical basis of model prediction. Methods: We retrospectively analyzed 1661 de-identified Korean-language counseling session transcripts obtained from the publicly available AI Hub “Mental Health Counseling Dialogue” dataset (Republic of Korea; sessions collected between 2021 and 2023 from accredited domestic mental health counseling centers). Each session averaged 30 min (≈5000 Korean characters). Labeling was performed by two licensed clinical psychologists (inter-rater Cohen’s κ = 0.82). A Hierarchical Attention Network with Bidirectional LSTM (HAN-BiLSTM) was constructed; performance was compared with six baselines (Flat LSTM, TextCNN, KR-BERT, KoBERT, KoELECTRA, KLUE-RoBERTa) using stratified 5-fold cross-validation, paired t-tests with Bonferroni correction, and McNemar’s test. Top-ranked SHAP tokens were independently rated for clinical face validity by three psychiatrists. Results: The proposed model outperformed the baseline model not only for the labels of depression (F1 = 0.90) and anxiety (F1 = 0.85) but also for substance use disorder (F1 = 0.78) with poor data, achieving a macro-averaged F1 of 0.84 (95% CI 0.82–0.86; all p < 0.001 versus baselines). As a result of the SHAP analysis, clinically significant keywords such as “I want to die,” “anxiety,” and “drink” were identified as the model’s main basis for judgment, accurately tracking the client’s state, which dynamically changed as the dialogue progressed; three independent psychiatrists rated 88.7% of the top-15 SHAP tokens per label as clinically meaningful (Fleiss’s κ = 0.76). Conclusions: This study demonstrated that a deep learning-based multi-label approach is effective in early screening of complex mental health problems. In particular, the introduction of explainable AI (XAI) increases clinicians’ trust and suggests that it can be used as an AI-based clinical decision support system (CDSS) in the future. Full article

Automotive roof racks are important lightweight accessories for vehicles, and their extrusion performance is affected by the coupled effects of material hot deformation behavior, die flow resistance and billet surface layer transport. In this study, Al-0.9Mg-0.6Si alloy samples were subjected to hot compression tests at 350–500 °C and strain rates of 0.01–10 s⁻¹. The corrected true stress–true strain data were used to establish and validate an Arrhenius-type constitutive model, which was then implemented in HyperXtrude to simulate the hot extrusion of an automotive roof rack profile. The hot working map showed that the main rheological instability region was located at high strain rates, and the preferred processing window was 437–500 °C and 0.01–0.6 s⁻¹. EBSD analysis showed that hot compression refined the microstructure relative to the initial average grain size of 173.147 μm, and the most uniform grain size distribution was obtained at 500 °C and 0.1 s⁻¹. The ODF results indicated strengthened {111}<121> and <110>//TD texture components after compression. The finite-element results showed that the standard deviation of outlet velocity (SDV), used here as an index of outlet flow uniformity, increased with ram speed, billet preheating temperature and die preheating temperature, but decreased with increasing container temperature. Finally, grain size and texture measurements from butt discard samples were compared with simulated surface layer flow paths, supporting the predicted difference between simple axial flow and complex recirculating flow near the die. Full article

This study examines the deformation behaviour of laser powder bed fusion-produced A20X aluminium alloy and its accurate representation using flow curve models that account for die–specimen friction. Tests across multiple strain rates at room temperature were conducted on a Gleeble 3800; force–displacement data were friction-corrected to derive constitutive flow curves. A mathematical model was developed to capture barrelling and its impact on the stress–strain response, yielding corrected stresses significantly lower than measured values and validating the correction. An equation linking key post-deformation geometric parameters to their mathematical representation correlated well with a calibrated 2D finite element model, which reliably predicted plastic strain and deformation. The model’s friction factors agreed with experimental data, enabling efficient determination of the friction coefficient. Microstructural analysis and micrographs supported the predicted plastic strain distributions. Together, the corrected experiments and validated simulations provide a robust description of A20X’s response and inform performance and application potential. Full article

Die swell is the dominant source of dimensional deviation in rubber profile extrusion. Because it is driven by recoverable elastic strain, a purely viscous baseline flow field cannot reproduce its speed dependence; a viscoelastic correction is required. This study presents, to the best of our knowledge, the first controlled comparison of a Carreau–Arrhenius baseline flow field against a fractional-order viscoelastic correction for carbon-black-filled EPDM across an industrial speed window. The viscoelastic correction (PyCFD-FMM) is a post-processing fractional-order viscoelastic swell correction built on the shared non-isothermal Polyflow Carreau–Arrhenius flow field, derived from a six-mode fractional Maxwell model parameterized from dynamic mechanical analysis via the Laun rule and closed through the Tanner recoverable-strain theory. Three carbon-black-filled EPDM compounds (Shore A 60–80) were extruded at four screw speeds (15–30 rpm) under instrumented conditions. Experimentally, swell ratios of 1.12–1.15 increase monotonically with screw speed (Fisher-combined $p=0.007$; measurement repeatability CV $\le 0.27$% across $n=4$ replicates per condition). The purely viscous baseline output gives a decreasing apparent swell–speed trend—opposite to experiment—whereas PyCFD-FMM recovers the correct increasing trend for all compounds. Under single-anchor hold-out evaluation at 20/25/30 rpm, the non-anchor MAPE decreases from 0.99% for the baseline flow-field output to 0.30% (PyCFD-FMM); an anchor-sensitivity check over all four rpm choices keeps the compound-averaged non-anchor MAPE within 0.27–0.39% and preserves the correct slope sign in every case. Swell decomposition into geometric baseline and net correction factor ($B_{\mathrm{PyCFD}}=B_{\mathrm{geom}}\times f_{\mathrm{corr}}$) confirms that the viscous baseline flow field captures flow-geometry effects but carries no elastic memory. Within the tested window, the viscoelastic correction meets a dual-gate criterion—correct slope sign and reduced non-anchor MAPE—which the purely viscous baseline cannot satisfy by construction. Full article

While anisotropic extrudate swell in polymer processing is fundamentally driven by physical viscoelastic recovery, this paper proposes a theoretical framework to explicitly isolate and map the purely geometric and kinematic components of this phenomenon. Serving as a mathematical proof-of-concept, a multi-velocity-centre hypothesis is proposed. By introducing a semi-empirical, lumped material-flow calibration parameter, the macroscopic diameter swell ratio is mathematically extended to the discrete local flow field of a rectangular slit die. To evaluate its validity, the analytical framework is subjected to a numerical test for kinematic consistency utilizing isothermal, inelastic power-law fluid CFD simulations, thereby separating geometric mapping from complex viscoelastic stress relaxation. Results indicate that analytical predictions show good agreement with CFD data (error < 5%) strictly within the core zone of high-aspect-ratio dies. However, due to the infinite-slit assumption, 3D flow kinematics near die edges induce velocity decay, leading to local deviations that require future empirical corrections. Although comprehensive physical extrusion experiments and non-isothermal viscoelastic coupling are required for industrial deployment, this semi-empirical kinematic mapping provides a foundational mathematical basis that could potentially inform future inverse die-profile design and shape distortion compensation. Full article

Epithelial, endothelial, and many connective tissue cells are normally attached to the extracellular matrix (ECM). These cells rely on the ECM for structural support, signaling, and regulation of their behavior. When these cells lose this attachment or are in an inappropriate location, these cells soon die by a mechanism called anoikis (homelessness). Anoikis is a programmed cell death of an apoptotic nature; however, it can, in certain cases, be overcome, and detached cells can survive in the absence of the correct signals from the ECM. This is the case of malignant cells, where anoikis resistance is a prerequisite for invasion and metastasis. Without anoikis resistance (anchorage-independency), tumors would be unable to abandon their normal sites and would invade neighboring tissues and metastasize at distant locations. Anoikis is the natural barrier against cancer progression. Therefore, overcoming anoikis is a major step in cellular transformation. Cancer cells have developed many successful strategies to bypass anoikis. The main mechanism, albeit not the only one, involves hyper-activating survival pathways and over-expressing anti-apoptotic molecules. There is a strong and intertwining association between epithelial–mesenchymal transition and anoikis resistance that is discussed in depth. A better understanding of these anoikis resistance mechanisms has led to the research and development of pharmaceuticals that can counteract them. Full article

Coronary artery disease (CAD) is a leading cause of death worldwide. Unfortunately, due to various reasons, this disease is currently spreading rapidly. Many heart disease sufferers die due to the inaccuracy of diagnostic tools or the delay in seeing a doctor. Therefore, the correct and timely diagnosis of this disease plays an important role in preventing deaths. The method used in this research to diagnose coronary artery disease (CAD) is a combination of the following algorithms: Support Vector Machine, Naïve Bayes, Logistic Regression, Random Forest, K-Nearest Neighbors, and XGBoost with ANOVA feature selection method. The dataset was evaluated using two complementary validation strategies: a hold-out test set and 10-fold cross-validation. In the proposed method, the SHAP algorithm was implemented on the output of the XGBoost model. Using this algorithm makes the output of the model interpretable and brings the model out of black box status. With the hold-out method, the K-Nearest Neighbor model with the features selected by the ANOVA method obtained an accuracy of 93.33%. Then, the Support Vector Machine and XGBoost models obtained the best results with an accuracy of 91.66%. With the 10-fold cross-validation method of the model, XGBoost achieved 86.16% accuracy and 87.41% recall value, which increased the results obtained in both methods compared to the state-of-the-art methods. Full article

This study investigates the melt-flow behavior of the AlSi₉Cu₃ alloy during high-pressure die casting using a combined experimental and numerical approach. A transparent die and a high-speed camera were used to capture the transient motion of the melt front, while a validated computational model reproduced the filling dynamics under identical boundary conditions. The influence of the gating-system geometry—particularly the gate thickness, flow-path length, and inlet cross-section—was analyzed with respect to filling velocity, filling time, and flow stability. To quantify hydraulic losses that arise in practical die-casting conditions, an empirical correction coefficient k₂ was introduced. Its value was obtained by regression analysis based on ten repeated measurements of filling time for each configuration. The deviation between the simulated and experimental velocities did not exceed 5%, demonstrating the reliability of the numerical model within the tested parameter range. The results show that the optimized gating design reduces flow instability, suppresses air entrapment zones, and yields a more uniform velocity distribution across the cavity. The empirical relations derived involving k₂ provide a practical tool for preliminary design of gating systems, enabling faster optimization without extensive trial-and-error procedures. The methodology presented in this work offers a validated basis for improving gating-system performance in high-pressure die casting of aluminum alloys. Full article

Induction motors are a significant consumer of electricity. One of the crucial elements of losses in an induction motor is core losses. Core losses become dominant in motors powered by an inverter at higher frequencies. The core sheet loss depends on cutting the core using a die or laser. The article presents a practical method for approximating loss characteristics, enabling the determination of losses with high accuracy and the approximation of the magnetization characteristic. The method’s accuracy was verified using sheet metal samples cut with both a guillotine and a laser. The method is an area method; therefore, it is well-suited for use in analytical methods and calculations of power losses based on FEM (Finite Element Method) post-processing. Then, the developed approximations were used to calculate losses in sample induction motors of different powers. The results indicate that the developed method is accurate, making it a viable alternative to the approximate correction factor. Full article

Modern digital systems rely on DRAM as main memory and flash-based SSDs for storage, forming the backbone of today’s computing infrastructure. As demands for faster processing and larger data services increase, the memory subsystems have become denser, pushing technologies to their physical limits and increasing susceptibility to faults. To ensure data integrity, two complementary approaches are employed: replacement-based techniques, which map defective cells to redundant areas, and error-correcting code (ECC) methods, which dynamically detect and correct errors. This paper theoretically investigates the most efficient use of redundancy for DRAM reliability by categorizing detects into hard faults and soft errors. Each scenario is evaluated in terms of required redundancy and residual error rate, using finite-length channel coding capacity. We compare the ECC schemes with BCH codes, which are widely favored in on-die ECC applications due to their low latency and decoding complexity. Full article

Interocclusal records (IORs) created with bite registration materials (BRMs) accurately reflect the opposing teeth’s physiological and anatomical associations in digital and traditional dentistry. This study assessed the linear dimensional accuracy of vinyl polysiloxane-based scannable and transparent BRMs over obligatory clinical time intervals (1, 24, 72, and 168 h/s). A total of 3 scannable [Flexitime Bite, Occlufast CAD, Virtual CADBite] and 3 transparent [Maxill Bite, Charmflex Bite, Defend ClearBite] VPS-based BRMs were divided into 28 subgroups by time interval: 1, 24, 72, and 168 h/s. Stereomicroscope measurements of 420 standardised disk-shaped specimens with three distinct linear distances between crossing vertical and horizontal lines were taken. Comparisons with the conventional BRM determined the scannable and transparent BRMs’ accuracy, while comparisons with die dimensions yielded linear dimensional changes. Statistical analysis used median rank scores, interquartile range, and median. Using a one-way ANOVA rank and Dunn test, differences were assessed between and within groups at a probability ‘p’ value of 0.05 (p ≤ 0.05). Mean linear dimensions for CAD and transparent IOR materials were [−0.06 (−0.24%) to −0.15 (−0.6%)] and [−0.06 (0.24%) to −0.10 (0.40%)] millimetres, respectively. Virtual CADBite and Maxill Bite had the lowest linear disagreement after 1 h, but both showed significant variations at 7 days. Other commercial brands maintained their clinically acceptable linear accuracy (0.11). Flexitime Bite (CAD) was the sole material with a linear accuracy above the clinical threshold. IOR shrinkage reduced the linear dimensions in all materials. Until 7 days, all IOR materials except Flexitime bite (CAD) were clinically correct. Virtual CADBite and Maxill bite changed significantly during 1 h and 7 days. Full article

There is no doubt that the proper development of the heart is important for its correct function, in addition, maturation processes of the heart are crucial as well. The actin-binding protein nexilin seems to take over central roles in the latter processes, as nexilin-deficient mice are phenotypically inconspicuous at birth but die within short time thereafter. Recently, it has been proposed that nexilin plays a role in the formation and function of transverse tubules (T-tubules), which are essential for excitation-contraction coupling in the hearts of mature animals. Although it has long been known that nexilin is subjected to alternative splicing, a molecular characterization of the respective isoforms is not yet available. Here, we describe novel nexilin splice variants and analyze their expression in tissues of mice and humans. Interestingly, nexilin isoforms segregate to myocyte- and epithelial-specific isoforms. Moreover, heart-specific isoforms of nexilin localize differently between atria and ventricles and are also expressed in the endothelial cells of blood vessels. Further, we narrowed down the critical exons in the actin-binding domains 1 and 2 (ABD1/2), and observed different self-interaction properties by recombinant protein interaction studies. Our results emphasize the diverse tissue and subcellular distribution of the individual nexilin isoforms and point to the importance of taking a closer look at the particular nexilin isoforms investigated. Full article

Extrusion welding of AlMgSi(Cu) alloys is carried out by using porthole dies, as a result of which hollow shapes are formed with longitudinal seam welds. In the case of the inappropriate selection of the chemical composition of the aluminium alloy or improper metal welding conditions, the weld may have reduced strength in relation to that of the base material, thus weakening the strength of structures based on aluminium extrudates. The prediction of metal welding conditions, depending on the chemical composition of the alloy, the temperature and the unit welding pressures, effectively supports the design of porthole dies, thus significantly reducing the number of necessary extrusion tests and die geometry corrections needed during its implementation in industrial practice, and consequently significantly reducing production costs. In this work, an original laboratory test device simulating the behaviour of metal in a welding chamber of a porthole die was applied to examine the ability of AlMgSi(Cu) alloys to produce high-quality joints. Two different chemical compositions of AlMgSi(Cu) aluminium alloys differing in Mg, Si and Cu contents were used: alloy no. 1A (0.68% wt. Mg, 1.04% wt. Si, 0.61% wt. Cu) and alloy no. 3A (0.8% wt. Mg, 1.21% wt. Si, 1.22% wt. Cu). The weldability tests were carried out under various welding temperatures of 450, 500 and 550 °C and under various welding pressures of 150 MPa, 250 MPa and 350 MPa. The microstructural changes in the produced welds were evaluated with the use of OM and SEM/EDS with chemical analysis in micro-areas, whereas the mechanical effects were evaluated by using a static tensile test. Samples after static tensile testing were subjected to fractographic tests to determine the nature of the fractures. The highest values of relative weld strength were obtained under the highest welding temperature of 550 °C and the highest unit welding pressure of 350 MPa: 87% for alloy number 1/1A (high-strength weld), and 62% for alloy number 6/3A (medium-strength weld). Finally, the extrusion tests were performed in industrial conditions with an examination of the EBSD structure and strength of the longitudinal welds. High values of relative weld strength for extrudates from alloy no. 1/1A and alloy no. 3A, 96% and 89%, respectively, were found, which confirmed the previous weldability testing results. Full article