bluuebunny/crossref_metadata_2025 huggingface dataset:
Trends in Cartilage Repair Techniques for Chondral Defects in the Hip in Germany: An Epidemiological Analysis from 2006 to 2022
Authors: Frischholz Sebastian , Heinz Tizian , Weißenberger Manuel , von Hertzberg-Boelch Sebastian Philipp , Anderson Philip , Lüdemann Martin , Jakuscheit Axel , Rudert Maximilian , Stratos Ioannis
Published: October 2024

Cartilage repair techniques for chondral defects in the hip are crucial for treating conditions like femoroacetabular impingement, developmental dysplasia, and osteonecrosis, especially in young patients to delay the progression of osteoarthritis. This study aims to present age and sex distributions and trends in hip-preserving surgeries in Germany from 2006 to 2022, analyzing 116,179 procedures using the German OPS coding system. The procedures were categorized into three groups: debridement, refixation, and regeneration. Arthroscopy was more common than arthrotomy (98,916 vs. 17,263). Males underwent more procedures than females (63,771 vs. 52,408). Debridement had a monomodal age distribution peaking at 43.42 years, while refixation and regeneration exhibited bimodal patterns. Regenerative procedures were primarily performed on younger patients (average 27.73 years). A Joinpoint analysis showed an initial increase in procedures, peaking around 2013, followed by a decline. Arthroscopic procedures peaked at approximately 9000 in 2013, whereas arthrotomies peaked at around 1200 after 2014. The decline in procedures post-2013 may reflect refined surgical indications and a shift towards outpatient settings. These findings underscore the trend towards minimally invasive, scaffold-based treatments, with regenerative techniques showing promising outcomes in younger patients. Future research should focus on prospective comparative studies and cost–benefit analyses to guide clinical decision-making.
Synthesis of Novel Thiazoles Based on (+)-Usnic Acid
Authors: Filimonov Aleksandr S. , Luzina Olga A. , Salakhutdinov Nariman F.
Published: October 2024

A series of usnic acid derivatives containing a thiazole ring with an amide substituent were synthesized. The convenient method for synthesis of these compounds is a reaction of 14-bromousnic acid with N-acylthioureas. Acylation of aminothiazole does not lead to the targeted compound.
Sintering and Tribological Properties of Ti3SiC2-TiSix Composite Sintered by High-Pressure High-Temperature Technology
Authors: Chen Yuqi , Li Liang , Han Ming , Sun Chaofan , Li Jin
Published: October 2024

The Ti3SiC2TiSix ceramic composite was synthesized in situ from a mixture of 3Ti:1.5Si:1.2C powders under pressures ranging from 2 to 5 GPa and temperatures of 1150 °C to 1400 °C. At medium and high temperatures (4–5 GPa and 1400 °C), Ti3SiC2 dissolves into the cubic TiC phase. SEM analysis revealed that the high-pressure-produced multilayer structure of Ti3SiC2 remained intact. The friction properties of Ti3SiC2-TiSix composites combined with copper and aluminum were studied under both dry and lubricated conditions. After the break-in period, the Ti3SiC2-TiSix/Al combination exhibited the lowest friction coefficient: approximately 0.2. In dry-sliding conditions, the friction coefficient varies between 0.5 and 0.8. The wear mechanisms for Ti3SiC2-TiSix composites paired with aluminum primarily involve pear groove wear and adhesive wear during dry friction. Irregularly shaped aluminum balls accumulate in the pear grooves and adhere to each other. With increasing sintering pressure, the average friction coefficient of Ti3SiC2-TiSix composites against Cu ball pairs first increases and then decreases. The wear rate of the samples did not vary significantly as the sintering pressure increased, whereas the wear rate of Cu balls decreased with increasing sintering pressure. The adhesive wear of the Ti3SiC2-TiSix composite with its Cu counterpart is stronger than that of the Al counterpart. Abrasive chips of Cu balls appeared in flake form and adhered to the contact interface.
Effect of Cryogenic Treatment on Residual Stress and Microstructure of 6061 Aluminum Alloy and Optimization of Parameters
Authors: Niu Xuemei , Chen Zhi , Jing Linwang , Huang Yao , Liu Yuhang
Published: October 2024

Residual stress induced by solution treatment in 6061 aluminum alloy can lead to workpiece deformation, or even premature failure. The efficiency of traditional heat treatment for relieving residual stress is relatively low. Therefore, this study introduces a novel cryogenic treatment technique to reduce residual stress. The optimal cryogenic process parameters were achieved by orthogonal experiments: cryogenic temperature of 113 K, holding time of 24 h, 1 cryogenic cycle, and a cooling rate of 3 K·min−1, and the residual stress of aluminum alloy was measured by the blind hole method. The microstructural evolutions in 6061 aluminum alloy were tested by OM, SEM, and TEM. The results show that the introduction of cryogenic treatment can reduce residual stress in 6061 aluminum alloy by 64%, mainly due to the reduction of dislocations and the uniform distribution of β’’ phase.
Lifing Assessment of Gas Turbine Blade Root Affected by Out-of-Tolerances
Authors: Manzini Federico , Cesaretti Alessandra , Bessone Andrea , Bagnera Francesco , Botto Daniele
Published: October 2024

Current and future heavy-duty gas turbines (GTs) are being developed as an alternative or support to renewable energy sources (RESs). Therefore, GTs are subjected to several instances of being switched on and off; thus, the material fatigue limit can be reached in a short time. In such a scenario, possible out-of-tolerances (OoTs) in critical components must be considered. In this paper, OoTs related to critical parameters in the attachment geometry of a rotor blade are considered to estimate their impact on component life through a 2D finite element (FE) analysis. First, a mesh refinement is performed to obtain mesh-independent results; second, OoT geometries are simulated to determine stresses and strains at the blade attachment and disc groove. The mesh refinement process is critical to ensure model accuracy for both nominal and OoT geometries. The results show that OoTs can lead to important reductions in the life of the intended component, both on the blade and disc sides. These results could be useful in updating the maintenance plan for components and could be used for future insights, with further work extending the study to 3D geometry, for example, and evaluating the effect of other geometries.
The Contribution of the Skin Microbiome to Psoriasis Pathogenesis and Its Implications for Therapeutic Strategies
Authors: Radaschin Diana Sabina , Tatu Alin , Iancu Alina Viorica , Beiu Cristina , Popa Liliana Gabriela
Published: October 2024

Psoriasis is a common chronic inflammatory skin disease, associated with significant morbidity and a considerable negative impact on the patients’ quality of life. The complex pathogenesis of psoriasis is still incompletely understood. Genetic predisposition, environmental factors like smoking, alcohol consumption, psychological stress, consumption of certain drugs, and mechanical trauma, as well as specific immune dysfunctions, contribute to the onset of the disease. Mounting evidence indicate that skin dysbiosis plays a significant role in the development and exacerbation of psoriasis through loss of immune tolerance to commensal skin flora, an altered balance between Tregs and effector cells, and an excessive Th1 and Th17 polarization. While the implications of skin dysbiosis in psoriasis pathogenesis are only starting to be revealed, the progress in the characterization of the skin microbiome changes in psoriasis patients has opened a whole new avenue of research focusing on the modulation of the skin microbiome as an adjuvant treatment for psoriasis and as part of a long-term plan to prevent disease flares. The skin microbiome may also represent a valuable predictive marker of treatment response and may aid in the selection of the optimal personalized treatment. We present the current knowledge on the skin microbiome changes in psoriasis and the results of the studies that investigated the efficacy of the different skin microbiome modulation strategies in the management of psoriasis, and discuss the complex interaction between the host and skin commensal flora.
A Machine Learning Model for Predicting the Propagation Rate Coefficient in Free-Radical Polymerization
Authors: Wang Yiming , Fang Yue , Zhou Haifan , Gao Hanyu
Published: October 2024

The propagation rate coefficient (kp) is one of the most crucial kinetic parameters in free-radical polymerization (FRP) as it directly governs the rate of polymerization and the resulting molecular weight distribution. The kp in FRP can typically be obtained through experimental measurements or quantum chemical calculations, both of which can be time consuming and resource intensive. Herein, we developed a machine learning model based solely on the structural features of monomers involved in FRP, utilizing molecular embedding and a Lasso regression algorithm to predict kp more efficiently and accurately. The result shows that the model achieves a mean absolute percentage error (MAPE) of only 5.49% in the predictions for four new monomers, which indicates that the model exhibits strong generalization capabilities and provides reliable and robust predictions. In addition, this model can accurately predict the influence of the ester side chain length of (meth)acrylates on kp, aligning well with established scientific knowledge. This approach offers a straightforward and practical model for other researchers to rapidly obtain accurate kp values by employing monomer structural information. The model is sufficiently general to apply to a wide range of (meth)acrylate and butadiene FRP monomers, thereby supporting kinetic modeling of polymerization reactions.
Enhancing the Efficacy of Active Pharmaceutical Ingredients in Medicinal Plants through Nanoformulations: A Promising Field
Authors: Chen Yuhao , Tang Yuying , Li Yuanbo , Rui Yukui , Zhang Peng
Published: October 2024

This article explores the emerging field of nanomedicine as a drug delivery system, aimed at enhancing the therapeutic efficacy of active pharmaceutical ingredients in medicinal plants. The traditional methods of applying medicinal plants present several limitations, such as low bioavailability, poor solubility, challenges in accurately controlling drug dosage, and inadequate targeting. Nanoformulations represent an innovative approach in drug preparation that employs nanotechnology to produce nanoscale particles or carriers, which are designed to overcome these limitations. Nanoformulations offer distinct advantages, significantly enhancing the solubility and bioavailability of drugs, particularly for the poorly soluble components of medicinal plants. These formulations effectively enhance solubility, thereby facilitating better absorption and utilization by the human body, which in turn improves drug efficacy. Furthermore, nanomedicine enables targeted drug delivery, ensuring precise administration to the lesion site and minimizing side effects on healthy tissues. Additionally, nanoformulations can regulate drug release rates, extend the duration of therapeutic action, and enhance the stability of treatment effects. However, nanoformulations present certain limitations and potential risks; their stability and safety require further investigation, particularly regarding the potential toxicity with long-term use. Nevertheless, nanomaterials demonstrate substantial potential in augmenting the efficacy of active pharmaceutical ingredients in medicinal plants, offering novel approaches and methodologies for their development and application.
Structural and Optical Properties of Nickel-Doped Zinc Sulfide
Authors: Alhassan Sultan , Alshammari Alhulw H. , Alotibi Satam , Alshammari Khulaif , Mohamed W. S. , Hadia N. M. A.
Published: October 2024

In this study, undoped and Ni-doped ZnS nanoparticles were fabricated using a hydrothermal method to explore their structural, optical, and surface properties. X-ray diffraction (XRD) analysis confirmed the cubic crystal structure of ZnS, with the successful incorporation of Ni ions at various doping levels (2%, 4%, 6%, and 8%) without disrupting the overall lattice configuration. The average particle size for undoped ZnS was found to be 5.27 nm, while the Ni-doped samples exhibited sizes ranging from 5.45 nm to 5.83 nm, with the largest size observed at 6% Ni doping before a reduction at higher concentrations. Fourier-transform infrared (FTIR) spectroscopy identified characteristic Zn–S vibrational bands, with shifts indicating successful Ni incorporation into the ZnS lattice. UV–visible spectroscopy revealed a decrease in the optical band gap from 3.72 eV for undoped ZnS to 3.54 eV for 6% Ni-doped ZnS, demonstrating tunable optical properties due to Ni doping, which could enhance photocatalytic performance under visible light. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) analyses confirmed the uniform distribution of Ni within the ZnS matrix, while X-ray photoelectron spectroscopy (XPS) provided further confirmation of the chemical states of the elements. Ni doping of ZnS nanoparticles alters the surface area and pore structure, optimizing the material’s textural properties for enhanced performance. These findings suggest that Ni-doped ZnS nanoparticles offer promising potential for applications in photocatalysis, optoelectronics, and other fields requiring specific band gap tuning and particle size control.
Glucose Oxidation Performance of Zinc Nano-Hexagons Decorated on TiO2 Nanotube Arrays
Authors: Wang Ke , Amani Hamedani Hoda
Published: October 2024

Electrochemically anodized TiO2 nanotube arrays (NTAs) were used as a support material for the electrodeposition of zinc nanoparticles. The morphology, composition, and crystallinity of the materials were examined using scanning electron microscopy (SEM). Electrochemical impedance spectroscopy (EIS) was performed to evaluate the electrochemical properties of TiO2 NTAs. Annealing post-anodization was shown to be effective in lowering the impedance of the TiO2 NTAs (measured at 1 kHz frequency). Zinc nanohexagons (NHexs) with a mean diameter of ~300 nm and thickness of 10–20 nm were decorated on the surface of TiO2 NTAs (with a pore diameter of ~80 nm and tube length of ~5 µm) via an electrodeposition process using a zinc-containing deep eutectic solvent. EIS and CV tests were performed to evaluate the functionality of zinc-decorated TiO2 NTAs (Zn/TiO2 NTAs) for glucose oxidation applications. The Zn/TiO2 NTA electrocatalysts obtained at 40 °C demonstrated enhanced glucose sensitivity (160.8 μA mM−1 cm−2 and 4.38 μA mM−1 cm−2) over zinc-based electrocatalysts reported previously. The Zn/TiO2 NTA electrocatalysts developed in this work could be considered as a promising biocompatible electrocatalyst material for in vivo glucose oxidation applications.
Unhealthy Eating Habits and Determinants of Diet Quality in Primary Healthcare Professionals in Poland: A Cross-Sectional Study
Authors: Znyk Małgorzata , Kaleta Dorota
Published: October 2024

Background/Objectives: The aim of this work was to understand the factors influencing the prevalence of dietary behaviors, as well as determinants of unhealthy eating and diet quality among primary care physicians and nurses in Poland. Methods: A cross-sectional study involving 161 doctors and 331 nurses was conducted in the years 2020–2022 in primary healthcare settings. Results: Unhealthy eating habits affected GPs aged 40–54 years (42.9%), females (64.3%), those of normal body weight (67.9%), representing private medical practice (67.9%), who had over 20 years of work experience (42.8%). Similarly, among the group of nurses, unhealthy eating habits were reported in subjects aged 40–54 (46.5%), individuals with normal body weights (49.5%), those with one chronic disease (38.4%), representing public medical practice (63.6%), with over 20 years of work experience (40.4%), seeing ≤100 patients during the work week (84.8%). The univariable logistic regression analyses for unhealthy dietary habits showed that overweight GPs had lower odds of unhealthy eating habits (OR = 0.35; 95% CI: 0.11–1.08; p < 0.05). Among the nurses, the odds of unhealthy eating habits increased with the number of years of work. Nurses with 10–20 years of work experience had 1.23 times greater odds of unhealthy eating habits, while people working for more than 20 years had 1.81 times greater odds of unhealthy eating habits than individuals working for a period shorter than ten years (OR = 1.23; 95% CI: 0.68–2.23; p > 0.05 vs. OR = 1.81; 95% CI: p < 0.05). The multivariable logistic regression analysis did not show statistically significant results. Conclusions: These issues should be addressed when planning educational activities aimed at supporting healthcare professionals in implementing lifestyle changes.
Activation of the Gut–Brain Interaction by Urolithin A and Its Molecular Basis
Authors: Kubota Daiki , Sato Momoka , Udono Miyako , Kohara Akiko , Kudoh Masatake , Ukawa Yuichi , Teruya Kiichiro , Katakura Yoshinori
Published: October 2024

Background: Urolithin A (Uro-A), a type of polyphenol derived from pomegranate, is known to improve memory function when ingested, in addition to its direct effect on the skin epidermal cells through the activation of longevity gene SIRT1. However, the molI ecular mechanism by which orally ingested Uro-A inhibits cognitive decline via the intestine remains unexplored. Objectives: This study aimed to evaluate the role of Uro-A in improving cognitive function via improved intestinal function and the effect of Uro-A on the inflammation levels and gene expression in hippocampus. Methods: Research to clarify the molecular basis of the functionality of Uro-A was also conducted. Results: The results demonstrated that Uro-A suppressed age-related memory impairment in Aged mice (C57BL/6J Jcl, male, 83 weeks old) by reducing inflammation and altering hippocampal gene expression. Furthermore, exosomes derived from intestinal cells treated with Uro-A and from the serum of Aged mice fed with Uro-A both activated neuronal cells, suggesting that exosomes are promising candidates as mediators of the Uro-A-induced activation of gut–brain interactions. Additionally, neurotrophic factors secreted from intestinal cells may contribute to the Uro-A-induced activation of gut–brain interactions. Conclusions: This study suggests that Uro-A suppresses age-related cognitive decline and that exosomes and other secreted factors may contribute to the activation of the gut–brain interaction. These findings provide new insights into the therapeutic potential of Uro-A for cognitive health.
Possible Health Benefits and Risks of DeepFake Videos: A Qualitative Study in Nursing Students
Authors: Navarro Martínez Olga , Fernández-García David , Cuartero Monteagudo Noemí , Forero-Rincón Olga
Published: October 2024

Background: “DeepFakes” are synthetic performances created by AI, using neural networks to exchange faces in images and modify voices. Objective: Due to the novelty and limited literature on its risks/benefits, this paper aims to determine how young nursing students perceive DeepFake technology, its ethical implications, and its potential benefits in nursing. Methods: This qualitative study used thematic content analysis (the Braun and Clarke method) with videos recorded by 50 third-year nursing students, who answered three questions about DeepFake technology. The data were analyzed using ATLAS.ti (version 22), and the project was approved by the Ethics Committee (code UCV/2021–2022/116). Results: Data analysis identified 21 descriptive codes, classified into four main themes: advantages, disadvantages, health applications, and ethical dilemmas. Benefits noted by students include use in diagnosis, patient accompaniment, training, and learning. Perceived risks include cyberbullying, loss of identity, and negative psychological impacts from unreal memories. Conclusions: Nursing students see both pros and cons in DeepFake technology and are aware of the ethical dilemmas it poses. They also identified promising healthcare applications that could enhance nurses’ leadership in digital health, stressing the importance of regulation and education to fully leverage its potential.
Bioengineering Tooth and Periodontal Organoids from Stem and Progenitor Cells
Authors: Torizal Fuad Gandhi , Noorintan Syarifah Tiara , Gania Zakiya
Published: October 2024

Tooth and periodontal organoids from stem and progenitor cells represent a significant advancement in regenerative dentistry, offering solutions for tooth loss and periodontal diseases. These organoids, which mimic the architecture and function of real organs, provide a cutting-edge platform for studying dental biology and developing therapies. Recent methodologies have been developed to optimize conditions for organoid production, advancing dental regenerative medicine, disease modeling, and developmental studies. The integration of bioengineering strategies with culture techniques enhances both our understanding and the therapeutic potential of these organoids. Additionally, factors such as the extracellular matrix, growth factors, and culture systems profoundly influence organoid formation and maturation. This review explores various bioengineering approaches for generating organoids, emphasizing the pivotal role of stem and progenitor cells.
The Functions of Cytokines in the Cardiac Immunopathogenesis of Chagas Disease
Authors: de Alba-Alvarado Mariana Citlalli , Cabrera-Bravo Margarita , Zenteno Edgar , Salazar-Schetino Paz María , Bucio-Torres Martha Irene
Published: October 2024

Chagas disease is a complex zoonosis. Clinically, it presents in two distinct phases, acute and chronic. The ability of patients to respond to Trypanosoma cruzi infection depends on the balance between inflammatory and anti-inflammatory responses, in which cytokines play a key regulatory role. In this review, we discuss the role of cytokines in regulating the host response and as mediators of cardiac injury by inducing profibrotic alterations. The importance of characterizing cytokine profiles as biomarkers of the evolution of cardiac damage in T.-cruzi-infected individuals is also emphasized.
Arylpiperazine Derivatives and Cancer: A New Challenge in Medicinal Chemistry
Authors: Andreozzi Giorgia , Corvino Angela , Severino Beatrice , Magli Elisa , Perissutti Elisa , Frecentese Francesco , Santagada Vincenzo , Caliendo Giuseppe , Fiorino Ferdinando
Published: October 2024

Background: In recent decades, there has been a startling rise in the number of cancer patients worldwide, which has led to an amazing upsurge in the development of novel anticancer treatment candidates. On a positive note, arylpiperazines have garnered attention in cancer research due to their potential as scaffolds for developing anticancer agents. These compounds exhibit a diverse array of biological activities, including cytotoxic effects against cancer cells. Indeed, one of the key advantages of arylpiperazines lies in their ability to interact with various molecular targets implicated in cancer pathogenesis. Aim: Here, we focus on the chemical structures of several arylpiperazine derivatives, highlighting their anti-proliferative activity in different tumor cell lines. The modular structure, diverse biological activities, and potential for combination therapies of arylpiperazine compounds make them valuable candidates for further preclinical and clinical investigations in the fight against cancer. Conclusion: This review, providing a careful analysis of different arylpiperazines and their biological applications, allows researchers to refine the chemical structures to improve potency, selectivity, and pharmacokinetic properties, thus advancing their therapeutic potential in oncology.
Optimizing Water, Temperature, and Density Conditions for In Vitro Pea (Pisum sativum L.) Germination
Authors: Kende Zoltán , Piroska Petra , Szemők Gabriella Erzsébet , Khaeim Hussein , Sghaier Asma Haj , Gyuricza Csaba , Tarnawa Ákos
Published: October 2024

This study aimed to determine the optimal water, temperature, and density conditions, alongside antifungal treatments, for pea (Pisum sativum L.) germination in a laboratory setting, with implications for research, breeding, and microgreen production. Germination and early seedling growth were assessed across various temperatures (5 °C to 40 °C), water levels (0–14 mL per Petri dish), seed densities (5, 7, 9, and 11 seeds per Petri dish), and antifungal treatments (Hypo and Bordeaux mixture). The results indicated that optimal germination occurred between 15 °C and 25 °C, with peak performance at 25 °C. Water levels between 7 and 11 mL per 9 cm diameter Petri dish supported robust root and shoot development, while minimal water levels initiated germination but did not sustain growth. Five seeds per Petri dish was optimal for healthy development, whereas higher densities led to increased competition and variable outcomes. Antifungal treatments showed slight improvements in germination and growth, though differences were not statistically significant compared to controls. The study’s novelty lies in its holistic approach to evaluating multiple factors affecting pea germination, offering practical guidelines for enhancing germination rates and seedling vigor. These findings support efficient and resilient crop production systems adaptable to varying environmental conditions, contributing to sustainable agriculture and food security. Future research should explore these factors in field settings and across different pea cultivars to validate and refine the recommendations.
Chlorophyll Fluorescence in Wheat Breeding for Heat and Drought Tolerance
Authors: Abdullaev Firuz , Pirogova Polina , Vodeneev Vladimir , Sherstneva Oksana
Published: October 2024

The constantly growing need to increase the production of agricultural products in changing climatic conditions makes it necessary to accelerate the development of new cultivars that meet the modern demands of agronomists. Currently, the breeding process includes the stages of genotyping and phenotyping to optimize the selection of promising genotypes. One of the most popular phenotypic methods is the pulse-amplitude modulated (PAM) fluorometry, due to its non-invasiveness and high information content. In this review, we focused on the opportunities of using chlorophyll fluorescence (ChlF) parameters recorded using PAM fluorometry to assess the state of plants in drought and heat stress conditions and predict the economically significant traits of wheat, as one of the most important agricultural crops, and also analyzed the relationship between the ChlF parameters and genetic markers.
Synthesis and Characterization of Rebondable Polyurethane Adhesives Relying on Thermo-Activated Transcarbamoylation
Authors: Bautista-Anguís Daniel , Reiner Lisbeth , Röper Florian , Maar Sebastian , Wolfahrt Markus , Wolfberger Archim , Schlögl Sandra
Published: October 2024

Dynamic polymer networks combine the noteworthy (thermo)mechanical features of thermosets with the processability of thermoplastics. They rely on externally triggered bond exchange reactions, which induce topological rearrangements and, at a sufficiently high rate, a macroscopic reflow of the polymer network. Due to this controlled change in viscosity, dynamic polymers are repairable, malleable, and reprocessable. Herein, several dynamic polyurethane networks were synthetized as model compounds, which were able to undergo thermo-activated transcarbamoylation for the use in rebondable adhesives. Ethylenediamine-N,N,N′,N′-tetra-2-propanol (EDTP) was applied as a transcarbamoylation catalyst, which participates in the curing reaction across its four -OH groups and thus, is covalently attached within the polyurethane network. Both bond exchange rate and (thermo)mechanical properties of the dynamic networks were readily adjusted by the crosslink density and availability of -OH groups. In a last step, the most promising model compound was optimized to prepare an adhesive formulation more suitable for a real case application. Single-lap shear tests were carried out to evaluate the bond strength of this final formulation in adhesively bonded carbon fiber reinforced polymers (CFRP). Exploiting the dynamic nature of the adhesive layer, the debonded CFRP test specimens were rebonded at elevated temperature. The results clearly show that thermally triggered rebonding was feasible by recovering up to 79% of the original bond strength.
Sulphur Copolymers with Pyrrole Compounds as Crosslinking Agents of Elastomer Composites for High-Performance Tyres
Authors: Naddeo Simone , Barbera Vincenzina , Galimberti Maurizio
Published: October 2024

Driving a car at extreme speeds, road holding, and sustainability do not go together well. Formula 1 racing is exciting but is not an example of sustainability. The aim of this work was to use materials, suitable for the treads of high-performance racing tyres, that can favour both high performance and sustainability. In particular, the objective was to achieve high dynamic rigidity at high temperatures (>100 °C) and a stable crosslinking network. A copolymer from an industrial waste such as sulphur and a comonomer from a circular biosourced material were used as the crosslinking agent of an elastomer composite based on poly(styrene-co-butadiene) from solution anionic polymerization and a carbon black with a high surface area. The biosourced circular material was 1,6-bis(2,5-dimethyl-1H-pyrrol-1-yl)hexane (HMDP), the di-pyrrole derivative of hexamethylenediamine. Two poly(S-co-HMDP) copolymers, with different S/HMDP ratios (6 and 8.9, Copolymer 1 and Copolymer 2) were carefully characterized by means of 1H-, 13C-, 2D1H-1H-COSY and 2D 1H-13C HSQC NMR. The comparison of the spectra highlighted the substitution with sulphur of the β-position of the pyrrole ring: mono-substitution largely prevailed in Copolymer 1 and also bi-substitution in Copolymer 2. The copolymers were used as additives in the vulcanization system. Compared with a reference composite, they allowed us to achieve more efficient vulcanization, a higher density of the crosslinking network, higher dynamic rigidity, better ultimate tensile properties, and better stability of the crosslinking network at high temperatures. Compared with a traditional oil-based crosslinking agent for elastomer composites with high rigidity and a stable structure at high temperatures, such as the perthiocarbamate 6-((dibenzylcarbamothioyl)disulfaneyl)hexyl 1,3-diphenylpropane-2-sulfinodithioate, the poly(S-co-HMDP) copolymers led to higher dynamic rigidity and better ultimate tensile properties. These improvements occurring simultaneously are definitely unusual. This work paves the way for the upcycling of circular materials in a large-scale application such as in tyres.
The Multi-Challenges of the Multi-Ion-Imprinted Polymer Synthesis
Authors: Zepeda-Navarro Abraham , Segoviano-Garfias José J. N. , Bivián-Castro Egla Yareth
Published: October 2024

Multi-ion-imprinted polymers (MIIPs) are materials with a wide range of applications mainly focused on environmental recovery, mining, technology, sensors, etc. MIIPs can incorporate ions such as heavy metals, transition metals, rare earth elements, radionuclides, and other types of ions. The chemical structures of MIIPs can be designed for different purposes and with certain morphologies, such as gels, crystals, or powders, and the surface area and porosity are also considered. All these properties provide the material with several desirable characteristics, like high selectivity, high specificity, adequate efficiency, good stability, the possibility of reusability, and strategy technology adaptation. In this review, we show the multitude of challenges of multi-ion imprinted polymer chemical synthesis based on the different and interesting methods reported previously.
Melt-Processed Polybutylene-Succinate Biocomposites with Chitosan: Development and Characterization of Rheological, Thermal, Mechanical and Antimicrobial Properties
Authors: Merijs-Meri Remo , Zicans Janis , Ivanova Tatjana , Mezule Linda , Ivanickins Aleksandrs , Bockovs Ivan , Bitenieks Juris , Berzina Rita , Lebedeva Alina
Published: October 2024

The current research is devoted to the development and characterization of green antimicrobial polymer biocomposites for food packaging applications. The biocomposites were developed by melt compounding on the basis of two different succinate polymer matrices with varying chain stiffness—polybutylene succinate (PBS) or its copolymer with 20 mol.% of polybutylene adipate (PBSA). Fungi chitosan oligosaccharide (C98) and crustacean chitosan (C95) were used as antimicrobial additives. The rheological properties of the developed biocomposites were determined to clear out the most suitable temperature for melt processing. In addition, mechanical, thermal, barrier and antimicrobial properties of the developed biocomposites were determined. The results of the investigation revealed that PBSA composites with 7 wt% and 10 wt% of the C98 additive were more suitable for the development of green packaging films because of their higher ultimate elongation values, better damping properties as well as their superior anti-microbial behavior. However, due to the lower thermal stability of the C98 additive as well as PBSA, the melt processing temperatures of the composites desirably should not exceed 120 °C. Additionally, by considering decreased moisture vapor barrier properties, it is recommended to perform further modifications of the PBSA-C98 composites through an addition of a nanoclay additive due to its excellent barrier properties and thermal stability.
Robust Strain Sensor with High Sensitivity Based on Polymer-Encapsulated Microfiber Mach–Zehnder Interferometer
Authors: Xiao Bin , Zhuang Funa , Wang Jing , Yao Zhongyu , Wang Shanshan
Published: October 2024

A robust strain sensor is demonstrated based on a microfiber Mach–Zehnder interferometer (MMZI) encapsulated by the polymer polydimethylsiloxane (PDMS). Benefiting from the low Young’s modulus of PDMS, both a robust structure and high sensitivity can be realized based on three different encapsulations. In the experiment, the proposed sensors are fabricated and tested with strain sensitivities ranging from −20.95 pm/με to 127.00 pm/με within the wavelength range of 1200–1650 nm. Compared with the bare MMZI sensor, at least one order of magnitude higher sensitivity is reached. To further evaluate the performance of the sensor, the dependences of sensitivity on probing wavelength and the different types and quantities of polymers used in encapsulation are discussed. Results show that the sensitivity of the sensor will increase with the probing wavelength. The type and quantity of polymer used are also very critical to sensitivity. Additionally, a response time of 24.72 ms can be reached. Good recoverability and repeatability of the sensor are also demonstrated by repeated experiments. The strain sensor demonstrated here shows the advantages of simple fabrication, robust structure, high and tunable sensitivity, fast response, good recoverability and repeatability.
Statistical Analysis of Large Format Additively Manufactured Polyethylene Terephthalate Glycol with 30% Carbon Fiber Tensile Data
Authors: Martin Katie A. , Burroughs Jedadiah F. , Riveros Guillermo A.
Published: October 2024

In large format additive manufacturing (LFAM), a keener understanding of the relationship between the manufacture method and material temperature dependency is needed for the production of large polymer parts. Statistical analyses supported by material properties and a meso-structural understanding of LFAM are applied to elucidate tensile data trends. The data from LFAM polyethylene terephthalate glycol with 30% carbon fiber (CF) (PETG CF30%) panels (diagonal, horizontal, and vertical in the x-y print plane) and injection-molded specimens tensile tested at six different testing temperatures (room temperature, 40 °C, 50 °C, 60 °C, 70 °C, and 80 °C) were used for statistical analyses. A standard deviation, a coefficient of variation, and a two-way and one-way analyses of variance (ANOVA) were conducted. The manufacturing method (44.2%) and temperature (47.4%) have a strong effect on the ultimate tensile strength, in which temperature (82.6%) dominates Young's modulus. To explain the difference between the ultimate tensile strength of vertical, diagonal, and horizontal specimens at room temperature, a visual inspection of the specimen failure was conducted and the maximum stress at the crack tip was calculated analytically. The decreased strength in the diagonal specimens resulted from the reliance on interlaminar adhesion strength. Future work will consider the effect of the void space variation on tensile strength variance.
Organic–Inorganic Hybrid Nanoparticles for Enhancing Adhesion of 2K Polyurethane to Steel and Their Performance Optimization Using Response Surface Methodology
Authors: Duong Thu , Le Manh , Lee Changhoon , Kim Juyoung
Published: October 2024

Automakers are focusing on lightweight vehicles to address fuel economy and emission challenges and are using high-performance materials such as 2K PU-based joints as alternatives to cast iron, steel, and other metals. This study was conducted with the aim of expanding the application of 2K PU and enhancing its compatibility with steel substrates, which are commonly used in the automotive manufacturing industry, through the use of O-I hybrid nanoparticles containing alkoxysilane groups as additives in the 2K PU formulation. At the same time, the simplified process introduced and examined in this study demonstrates its feasibility for industrial-scale applications; the process offers notable advantages in reducing workload and curing time by eliminating cumbersome surface pretreatment steps before applying the 2K PU layer. Two types of commercial SB PU and EB PU were selected to study the mechanism by which O-I hybrid NPs enhance adhesion when integrated directly into the 2K PU formulation. We optimized various input parameters through practical work and modeling using the response surface method. These parameters included the amounts of AFAP precursor, APTES, and butylene glycol (BG) and the mixing ratio of O-I hybrid NPs in the formulations of two commercial PUs. The results show that O-I hybrid NPs significantly enhance adhesion, increasing performance on stainless surfaces by up to 2.35 times compared to pristine EB and SB PU. Notably, the SB PU’s performance can improve up to 2.5 times according to the RSM predictions, highlighting the substantial impact of O-I hybrid NPs.
Dynamic Behavior of Rubber Fiber-Reinforced Expansive Soil under Repeated Freeze–Thaw Cycles
Authors: Sun Zhenxing , Wang Rongchang , Yang Zhongnian , Lv Jianhang , Shi Wei , Ling Xianzhang
Published: October 2024

Large volumes of waste tires are generated due to the rapid growth of the transportation industry. An effective method of recycling waste tires is needed. Using rubber from tires to improve problematic soils has become a research topic. In this paper, the dynamic response of rubber fiber-reinforced expansive soil under freeze–thaw cycles is investigated. Dynamic triaxial tests were carried out on rubber fiber-reinforced expansive soil subjected to freeze–thaw cycles. The results showed that with the increase in the number of freeze–thaw cycles, the dynamic stress amplitude and dynamic elastic modulus of rubber fiber-reinforced expansive soils first decrease and then increase, and the damping ratio first increases and then decreases, all of which reach the turning point at the 6th freeze–thaw cycle. The dynamic stress amplitude and dynamic elastic modulus decreased by 59.4% and 52.2%, respectively, while the damping ratio increased by 99.8% at the 6th freeze–thaw cycle. The linear visco-elastic model was employed to describe the hysteretic curve of rubber fiber-reinforced expansive soil. The elastic modulus of the linear elastic element and the viscosity coefficient of the linear viscous element first decrease and then increase with the increase in the number of freeze–thaw cycles; all reach the minimum value at the 6th freeze–thaw cycle. The dynamic stress–dynamic strain curve calculation method is established based on the hyperbolic model and linear visco-elastic model, and the verification shows that the effect is better. The research findings provide guidance for the improvement of expansive soil in seasonally frozen regions.
Personality Traits and Mental Health: Considering the Role of Age
Authors: Kang Weixi , Malvaso Antonio
Published: October 2024

Personality traits are dispositional characteristics that capture basic individual differences. The Big Five model is one of the most studied personality models and can be conceptualized using other personality models as well. Personality traits are also closely associated with mental health, which is our general state of well-being. However, it is largely unknown how the relationships between the Big Five personality traits and mental health may differ with age. By analyzing data using hierarchical regression and multiple regressions, the current research found that age modulates the associations between all Big Five personality traits (i.e., Neuroticism, Agreeableness, Openness, Conscientiousness, and Extraversion) and mental health. These findings can be mostly explained by predominant development theories. The current study indicates the necessity for considering age differences when investigating the relationships between the Big Five personality traits and mental health. Psychologists may want to work out a way to improve mental health based on age and personality characteristics.
Progressive Unsupervised Domain Adaptation for Radio Frequency Signal Attribute Recognition across Communication Scenarios
Authors: Xiao Jing , Zhang Hang , Shao Zeqi , Zheng Yikai , Ding Wenrui
Published: October 2024

As the development of low-altitude economies and aerial countermeasures continues, the safety of unmanned aerial vehicles becomes increasingly critical, making emitter identification in remote sensing practices more essential. Effective recognition of radio frequency (RF) signal attributes is a prerequisite for identifying emitters. However, due to diverse wireless communication environments, RF signals often face challenges from complex and time-varying wireless channel conditions. These challenges lead to difficulties in data collection and annotation, as well as disparities in data distribution across different communication scenarios. To address this issue, this paper proposes a progressive maximum similarity-based unsupervised domain adaptation (PMS-UDA) method for RF signal attribute recognition. First, we introduce a noise perturbation consistency optimization method to enhance the robustness of the PMS-UDA method under low signal-to-noise conditions. Subsequently, a progressive label alignment training method is proposed, combining sample-level maximum correlation with distribution-level maximum similarity optimization techniques to enhance the similarity of cross-domain features. Finally, a domain adversarial optimization method is employed to extract domain-independent features, reducing the impact of channel scenarios. The experimental results demonstrate that the PMS-UDA method achieves superior recognition performance in automatic modulation recognition and RF fingerprint identification tasks, as well as across both ground-to-ground and air-to-ground scenarios, compared to baseline methods.
Deep Hybrid Fusion Network for Inverse Synthetic Aperture Radar Ship Target Recognition Using Multi-Domain High-Resolution Range Profile Data
Authors: Deng Jie , Su Fulin
Published: October 2024

Most existing target recognition methods based on high-resolution range profiles (HRRPs) use data from only one domain. However, the information contained in HRRP data from different domains is not exactly the same. Therefore, in the context of inverse synthetic aperture radar (ISAR), this paper proposes an advanced deep hybrid fusion network to utilize HRRP data from different domains for ship target recognition. First, the proposed network simultaneously processes time-domain HRRP and its corresponding time–frequency (TF) spectrogram through two branches to obtain initial features from the two HRRP domains. Next, a feature alignment module is used to make the fused features more discriminative regarding the target. Finally, a decision fusion module is designed to further improve the model’s prediction performance. We evaluated our approach using both simulated and measured data, encompassing ten different ship target types. Our experimental results on the simulated and measured datasets showed an improvement in recognition accuracy of at least 4.22% and 2.82%, respectively, compared to using single-domain data.
Cyber–Physical Perception Interface for Co-Simulation Applications
Authors: Mîndra Teodora , Anghel Ana Magdalena
Published: October 2024

Co-simulation can bring improvements to the development of cyber–physical perceptive systems (CPPS) in critical fields, allowing uninterrupted system operation and flexibility to use both real-time sensor data and non-real-time data. This paper proposes a co-simulation approach that integrates physical systems and communication systems, including both hardware and software components. This study demonstrates how systems of different natures with discrete or continuous events can be simulated using three methods: time stepped, global event driven, and variable stepped. Through two case studies from the medical and energy fields, CPPS and co-simulation reveal their importance for the future by improving precision and efficiency, which leads to more accurate diagnoses and personalized treatments in the medical field and increases the stability of energy networks.
Gear Classification in Skating Cross-Country Skiing Using Inertial Sensors and Deep Learning
Authors: Pousibet-Garrido Antonio , Polo-Rodríguez Aurora , Moreno-Pérez Juan Antonio , Ruiz-García Isidoro , Escobedo Pablo , López-Ruiz Nuria , Marcen-Cinca Noel , Medina-Quero Javier , Carvajal Miguel Ángel
Published: October 2024

The aim of this current work is to identify three different gears of cross-country skiing utilizing embedded inertial measurement units and a suitable deep learning model. The cross-country style studied was the skating style during the uphill, which involved three different gears: symmetric gear pushing with poles on both sides (G3) and two asymmetric gears pushing with poles on the right side (G2R) or to the left side (G2L). To monitor the technique, inertial measurement units (IMUs) were affixed to the skis, recording acceleration and Euler angle data during the uphill tests performed by two experienced skiers using the gears under study. The initiation and termination points of the tests were controlled via Bluetooth by a smartphone using a custom application developed with Android Studio. Data were collected on the smartphone and stored on the SD memory cards included in each IMU. Convolutional neural networks combined with long short-term memory were utilized to classify and extract spatio-temporal features. The performance of the model in cross-user evaluations demonstrated an overall accuracy of 90%, and it achieved an accuracy of 98% in the cross-scene evaluations for individual users. These results indicate a promising performance of the developed system in distinguishing between different ski gears within skating styles, providing a valuable tool to enhance ski training and analysis.