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Found 6334 publications
Influence of Torsional Stiffness in Badminton Footwear on Lower Limb Biomechanics
Publication Name: Journal of Sports Science and Medicine
Publication Date: 2024-03-01
Volume: 23
Issue: 1
Page Range: 196-208
Description:
Torsional stiffness of athletic footwear plays a crucial role in pre-venting injury and improving sports performance. Yet, there is a lack of research focused on the biomechanical effect of torsional stiffness in badminton shoes. This study aimed to comprehen-sively investigate the influence of three different levels of torsional stiffness in badminton shoes on biomechanical character-istics, sports performance, and injury risk in badminton players. Fifteen male players, aged 22.8 ± 1.96 years, participated in the study, performing badminton-specific tasks, including forehand clear stroke [left foot (FCL) and right foot (FCR)], 45-degree sidestep cutting (45C), and consecutive vertical jumps (CVJ). The tasks were conducted wearing badminton shoes of torsional stiffness measured with Shore D hardness 50, 60, and 70 (referred to as 50D, 60D, and 70D, respectively). The primary biomechanical parameters included ankle, knee, and MTP joint kinematics, ankle and knee joint moments, peak ground reaction forces, joint range of motion (ROM), and stance time. A one-way repeated measures ANOVA was employed for normally distributed data and Fried-man tests for non-normally distributed data. The 70D shoe exhib-ited the highest ankle dorsiflexion and lowest ankle inversion peak angles during 45C task. The 60D shoe showed significantly lower knee abduction angle and coronal motions compared to the 50D and 70D shoes. Increased torsional stiffness reduced stance time in the FCR task. No significant differences were observed in anterior-posterior and medial-lateral ground reaction forces (GRF). However, the 70D shoe demonstrated higher vertical GRF than the 50D shoe while performing the FCR task, particularly during 70%-75% of stance. Findings from this study revealed the significant role of torsional stiffness in reducing injury risk and optimizing performance during badminton tasks, indicating that shoes with an intermediate level of stiffness (60D) could provide a beneficial balance between flexibility and stability. These findings may provide practical references in guiding future badminton shoe research and development. Further research is nec-essary to explore the long-term effects of altering stiffness, con-sidering factors such as athletic levels and foot morphology, to understand of the influence of torsional stiffness on motion bio-mechanics and injury prevalence in badminton-specific tasks.
Open Access: Yes
Numerical Covariance Evaluation for Linear Structures Subject to Non-Stationary Random Inputs
Publication Name: Computation
Publication Date: 2024-03-01
Volume: 12
Issue: 3
Page Range: Unknown
Description:
Random vibration analysis is a mathematical tool that offers great advantages in predicting the mechanical response of structural systems subjected to external dynamic loads whose nature is intrinsically stochastic, as in cases of sea waves, wind pressure, and vibrations due to road asperity. Using random vibration analysis is possible, when the input is properly modeled as a stochastic process, to derive pieces of information about the structural response with a high quality (if compared with other tools), especially in terms of reliability prevision. Moreover, the random vibration approach is quite complex in cases of non-linearity cases, as well as for non-stationary inputs, as in cases of seismic events. For non-stationary inputs, the assessment of second-order spectral moments requires resolving the Lyapunov matrix differential equation. In this research, a numerical procedure is proposed, providing an expression of response in the state-space that, to our best knowledge, has not yet been presented in the literature, by using a formal justification in accordance with earthquake input modeled as a modulated white noise with evolutive parameters. The computational efforts are reduced by considering the symmetry feature of the covariance matrix. The adopted approach is applied to analyze a multi-story building, aiming to determine the reliability related to the maximum inter-story displacement surpassing a specified acceptable threshold. The building is presumed to experience seismic input characterized by a non-stationary process in both amplitude and frequency, utilizing a general Kanai–Tajimi earthquake input stationary model. The adopted case study is modeled in the form of a multi-degree-of-freedom plane shear frame system.
Open Access: Yes
A new method applied for explaining the landing patterns: Interpretability analysis of machine learning
Publication Name: Heliyon
Publication Date: 2024-02-29
Volume: 10
Issue: 4
Page Range: Unknown
Description:
As one of many fundamental sports techniques, the landing maneuver is also frequently used in clinical injury screening and diagnosis. However, the landing patterns are different under different constraints, which will cause great difficulties for clinical experts in clinical diagnosis. Machine learning (ML) have been very successful in solving a variety of clinical diagnosis tasks, but they all have the disadvantage of being black boxes and rarely provide and explain useful information about the reasons for making a particular decision. The current work validates the feasibility of applying an explainable ML (XML) model constructed by Layer-wise Relevance Propagation (LRP) for landing pattern recognition in clinical biomechanics. This study collected 560 groups landing data. By incorporating these landing data into the XML model as input signals, the prediction results were interpreted based on the relevance score (RS) derived from LRP. The interpretation obtained from XML was evaluated comprehensively from the statistical perspective based on Statistical Parametric Mapping (SPM) and Effect Size. The RS has excellent statistical characteristics in the interpretation of landing patterns between classes, and also conforms to the clinical characteristics of landing pattern recognition. The current work highlights the applicability of XML methods that can not only satisfy the traditional decision problem between classes, but also largely solve the lack of transparency in landing pattern recognition. We provide a feasible framework for realizing interpretability of ML decision results in landing analysis, providing a methodological reference and solid foundation for future clinical diagnosis and biomechanical analysis.
Open Access: Yes
3D printing parameters optimization for Fe-6.5 wt%Si
Publication Name: Journal of Magnetism and Magnetic Materials
Publication Date: 2024-02-15
Volume: 592
Issue: Unknown
Page Range: Unknown
Description:
Optimization of 3D printing parameters was studied for the difficult to print, brittle Fe-6.5 wt%Si, applying powder bed fusion (PBF) technology. Printing orientation, volumetric energy density (VED), built plate (BP) temperature, as deposition parameters and the influence of post-deposition heat treatment (HT), were investigated. The optimal parameters were established based on the EBSD figures of samples deposited in different orientations, optical microscopy images, CT measurements, DC hysteresis curves, complex permeability spectra, and XRD patterns.
Open Access: Yes
Thermal, thermomechanical and structural properties of recycled polyethylene terephthalate (rPET)/waste marble dust composites
Publication Name: Heliyon
Publication Date: 2024-02-15
Volume: 10
Issue: 3
Page Range: Unknown
Description:
The main objective of this work is to review the capability of using waste marble dust (MD) particles as reinforcing materials in recycled polymeric composites to achieve environmentally friendly materials. In the present study, polymer composites were fabricated from recycled polyethylene terephthalate (rPET) and MD and then analyzed for their structural and thermal properties. Preparation of rPET-based composites containing 0–20 wt% MD was carried out through extrusion and injection molding. For their characterization Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA) were applied. The DSC analysis revealed a nucleating effect of MD on rPET, which was manifested in a higher crystallization temperature (196.7 °C ⇒ 204.4 °C); however, the marble particles were also found to hamper chain mobility, thereby decreasing the crystallinity ratio (23.7 % ⇒ 19.2 %) of rPET and altering its crystalline structure. According to the TGA measurements, a slight increase occurred in the thermal stability of rPET, its major decomposition temperature increased from 446 °C to 451 °C when 20 wt% MD was incorporated into it. DMA showed an improved stiffness in the entire investigated temperature range for MD-filled composites versus neat rPET. Additionally, several factors were derived from the DMA data, including the effectiveness factor, degree of entanglement, and reinforcing efficiency factor which all suggested a decent interaction between the components indicating a proper reinforcing ability of marble powder. However, above 5 wt% MD content the reinforcing efficiency deteriorated due to the agglomeration of filler particles, which was also supported by scanning electron microscopic images.
Open Access: Yes
Investigation on the physico-chemical properties of soil and mineralization of three selected tropical tree leaf litter
Publication Name: Environmental Research
Publication Date: 2024-02-15
Volume: 243
Issue: Unknown
Page Range: Unknown
Description:
Plant leaf litter has a major role in the structure and function of soil ecosystems as it is associated with nutrient release and cycling. The present study is aimed to understand how well the decomposing leaf litter kept soil organic carbon and nitrogen levels stable during an incubation experiment that was carried out in a lab setting under controlled conditions and the results were compared to those from a natural plantation. In natural site soil samples, Anacardium. occidentale showed a higher value of organic carbon at surface (1.14%) and subsurface (0.93%) and Azadirachta. indica exhibited a higher value of total nitrogen at surface (0.28%) and subsurface sample (0.14%). In the incubation experiment, Acacia auriculiformis had the highest organic carbon content initially (5.26%), whereas A. occidentale had the highest nitrogen level on 30th day (0.67%). The overall carbon-nitrogen ratio showed a varied tendency, which may be due to dynamic changes in the complex decomposition cycle. The higher rate of mass loss and decay was observed in A. indica leaf litter, the range of the decay constant is 1.26–2.22. The morphological and chemical changes of soil sample and the vermicast were substantained using scanning electron microscopy (SEM) and Fourier transmission infrared spectroscopy (FT-IR).
Open Access: Yes
Comparison of plant biostimulating properties of Chlorella sorokiniana biomass produced in batch and semi-continuous systems supplemented with pig manure or acetate
Publication Name: Journal of Biotechnology
Publication Date: 2024-02-10
Volume: 381
Issue: Unknown
Page Range: 27-35
Description:
Microalgae-derived biostimulants provide an eco-friendly biotechnology for improving crop productivity. The strategy of circular economy includes reducing biomass production costs of new and robust microalgae strains grown in nutrient-rich wastewater and mixotrophic culture where media is enriched with organic carbon. In this study, Chlorella sorokiniana was grown in 100 l bioreactors under sub-optimal conditions in a greenhouse. A combination of batch and semi-continuous cultivation was used to investigate the growth, plant hormone and biostimulating effect of biomass grown in diluted pig manure and in nutrient medium supplemented with Na-acetate. C. sorokiniana tolerated the low light (sum of PAR 0.99 ± 0.18 mol/photons/(m2/day)) and temperature (3.7–23.7° C) conditions to maintain a positive growth rate and daily biomass productivity (up to 149 mg/l/day and 69 mg/l/day dry matter production in pig manure and Na-acetate supplemented cultures respectively). The protein and lipid content was significantly higher in the biomass generated in batch culture and dilute pig manure (1.4x higher protein and 2x higher lipid) compared to the Na-acetate enriched culture. Auxins indole-3-acetic acid (IAA) and 2-oxindole-3-acetic acid (oxIAA) and salicylic acid (SA) were present in the biomass with significantly higher auxin content in the biomass generated using pig manure (> 350 pmol/g DW IAA and > 84 pmol/g DW oxIAA) compared to cultures enriched with Na-acetate and batch cultures (< 200 pmol/g DW IAA and < 27 pmol/g DW oxIAA). No abscisic acid and jasmonates were detected. All samples had plant biostimulating activity measured in the mungbean rooting bioassay with the Na-acetate supplemented biomass eliciting higher rooting activity (equivalent to 1–2 mg/l IBA) compared to the pig manure (equivalent to 0.5–1 mg/l IBA) and batch culture (equivalent to water control) generated biomass. Thus C. sorokiniana MACC-728 is a robust new strain for biotechnology, tolerating low light and temperature conditions. The strain can adapt to alternative nutrient (pig manure) and carbon (acetate) sources with the generated biomass having a high auxin concentration and plant biostimulating activity detected with the mungbean rooting bioassay.
Open Access: Yes
Investigation of Shear Strength Reduction Method in Slope Stability of Reinforced Slopes by Anchor and Nail
Publication Name: Buildings
Publication Date: 2024-02-01
Volume: 14
Issue: 2
Page Range: Unknown
Description:
Since the stability of slopes in infrastructures such as road and railroad embankments, excavations, and, in general, earthwork is important, analyzing the stability of these slopes has been one of the main focuses of geotechnical engineers. Although analyzing both reinforced and unreinforced slopes is needed, reinforced slopes require special attention as the reinforcement elements significantly affect the calculations. Hence, the current study’s aim is to find out the differences between obtained safety factors using the Limit Equilibrium Method (LEM) and Shear Strength Reduction Method (SSRM). For this purpose, first, the origin differences in terms of Safety Factor (SF) are theoretically determined according to basic formulas for the aforementioned techniques. Then, to verify the formula, several numerical modelings are carried out using in situ measured geotechnical data to better understand the differences in terms of safety factors. The results indicate that for the reinforced slope with an SF value of higher than 1, the SSRM provides a higher SF in comparison with the other techniques, and the origin of this difference is the definitions of the SF in the different methods.
Open Access: Yes
Classification of preeclampsia according to molecular clusters with the goal of achieving personalized prevention
Publication Name: Journal of Reproductive Immunology
Publication Date: 2024-02-01
Volume: 161
Issue: Unknown
Page Range: Unknown
Description:
The prevention of pre-eclampsia is difficult due to the syndromic nature and multiple underlying mechanisms of this severe complication of pregnancy. The current clinical distinction between early- and late-onset disease, although clinically useful, does not reflect the true nature and complexity of the pathologic processes leading to pre-eclampsia. The current gaps in knowledge on the heterogeneous molecular pathways of this syndrome and the lack of adequate, specific diagnostic methods are major obstacles to early screening and tailored preventive strategies. The development of novel diagnostic tools for detecting the activation of the identified disease pathways would enable early, accurate screening and personalized preventive therapies. We implemented a holistic approach that includes the utilization of different proteomic profiling methods of maternal plasma samples collected from various ethnic populations and the application of systems biology analysis to plasma proteomic, maternal demographic, clinical characteristic, and placental histopathologic data. This approach enabled the identification of four molecular subclasses of pre-eclampsia in which distinct and shared disease mechanisms are activated. The current review summarizes the results and conclusions from these studies and the research and clinical implications of our findings.
Open Access: Yes
