bluuebunny/crossref_metadata_2025 huggingface dataset:
Analytical and Experimental Study of the Start of the Chip Removal in Rotational Turning
Authors: Sztankovics István
Published: October 2024

The present challenges in the automotive industry require the development and practical implication of novel machining procedures, which will provide appropriate solutions. These procedures should still meet the requirements of productivity, surface quality and energy efficiency. The further development of novel machining procedures introduces new problems that did not occur (or occurred to a lesser extent) with traditionally applied procedures. Rotational turning has come to the attention of production engineers in the previous decade since it can be used to machine ground-like surfaces in an ecologically friendly and highly productive manner. However, the chip removal characteristic is slightly different from traditional turning due to the applied special kinematic relation and complex tool edge geometry. The run-in phase will take longer, which is the time period between the first contact of the tool and the formation of a constant chip cross-sectional area. The clarification of the chip formation is important in any machining procedure. To achieve this goal, the geometric parameters of the chip must be determined. Since the start of the chip removal is a crucial stage in rotational turning due to its length, the chip height, chip width and the cross-sectional area of the chip should be separately defined in the initial stage. Therefore, in this paper, the initial phase of chip removal in rotational turning is studied. The increasing cross-sectional area of the chip is determined analytically by the application of the previously elaborated equation of the cut surface. Calculating formulas are defined for the different stages of the start of the chip removal, which could be used in the forthcoming studies to analyze the chip formation. The effects of different determining parameters are analyzed theoretically by the deduced formulas of the run-in phase and practical experiments are also carried out. The analytical and experimental analyses showed that increasing feed also increases the dynamic load on the cutting edge, while the depth of cut lowers the growth of the characteristic parameters of the chip, which results in a lower dynamic load on the tool.
Innovative Strategies and Methodologies in Antimicrobial Peptide Design
Authors: Verma Devesh Pratap , Tripathi Amit Kumar , Thakur Ashwani Kumar
Published: October 2024

Multiple lines of research have led to the hypothesis that antimicrobial peptides (AMPs) are an important component of the innate immune response, playing a vital role in the defense against a wide range of infectious diseases. In this review, we explore the occurrence and availability of antimicrobial proteins and peptides across various species, highlighting their natural abundance and evolutionary significance. The design of AMPs has been driven by the identification of key structural and functional features, which are essential for optimizing their antimicrobial activity and reducing toxicity to host cells. We discuss various approaches, including rational design, high-throughput screening, and computational modeling, that have been employed to develop novel AMPs with enhanced efficacy. A particular focus is given to the identification and characterization of peptide fragments derived from naturally occurring host defense proteins, which offer a promising avenue for the discovery of new AMPs. The incorporation of artificial intelligence (AI) and machine learning (ML) tools into AMP research has further accelerated the identification, optimization, and application of these peptides. This review also discusses the current status and therapeutic potential of AMPs, emphasizing their role in addressing the growing issue of antibiotic resistance. The conclusion highlights the importance of continued research and innovation in AMP development to fully harness their potential as next-generation antimicrobial agents.
Assessment of a Tropical Transition over the Southwestern South Atlantic Ocean: The Case of Cyclone Akará
Authors: Reboita Michelle Simões , Nogueira Natan Chrysostomo de Oliveira , Gomes Isabelly Bianca dos Santos , Palma Lucas Lemos da Cunha , da Rocha Rosmeri Porfírio
Published: October 2024

Tropical cyclones are rare in the South Atlantic Ocean. Hurricane Catarina (2004), developed from a tropical transition, was the first documented case, followed by Iba (2019), which had a purely tropical genesis. In February 2024, the southeastern South Atlantic recorded its third tropical cyclone, Akará, initially a subtropical system. Due to the specific conditions required for tropical cyclones to develop in this ocean basin, the main purpose of this study is to describe the physical mechanisms that triggered the genesis of Akará’s precursor and its tropical transition. Data from various sources and methodologies, including the cyclone phase space diagram, are used in this study. Results show that the passage of a cold front created an environment with horizontal wind shear, contributing to most of the cyclonic relative vorticity in the genesis region. This was the primary driver of cyclogenesis at 1200 UTC on 15 February, along with other secondary processes. The tropical transition occurred as the vertical shear weakened, and turbulent heat fluxes from the ocean to the atmosphere increased, enhancing diabatic processes that warmed the atmosphere. This led to the tropical transition at 0600 UTC on 17 February.
A Novel Concept for Steel Building Cost Estimation in Shipbuilding Using Process and Product Similarities
Authors: Alblas Gerrit , Pruyn Jeroen
Published: October 2024

Accurate cost estimates are essential for staying in business in a competitive shipbuilding industry. With new technologies and the energy transition creating an ever-changing landscape, traditional cost estimation methods based on product specifications can no longer keep pace. The need for improvement especially arises for Engineering-To-Order projects, considering that the profit margins are narrow. The use of process information in the estimation process could increase the reliability and flexibility of these estimations. This article presents a concept that utilizes graph theory to include process information in the cost estimations applied to steel buildings. This concept is specifically suited for the early stages of Engineering-To-Order projects.
A Theoretical Model for the Hydraulic Permeability of Clayey Sediments Considering the Impact of Pore Fluid Chemistry
Authors: Cao Lixue , Zhao Hang , Yang Baokai , Zhang Jian , Song Hongzhi , Fu Xiaomin , Liu Lele
Published: October 2024

The chemistry of the pore fluid within clayey sediments frequently changes in various processes. However, the impacts of pore fluid chemistry have not been well included in the hydraulic permeability model, and the physical bases behind the salinity sensitivity of the hydraulic permeability remains elusive. In this study, a theoretical model for the hydraulic permeability of clayey sediments is proposed, and impacts of the pore fluid chemistry are quantitatively considered by introducing electrokinetic flow theory. Available experimental data were used to verify the theoretical model, and the verified model was further applied as a sensitivity analysis tool to explore more deeply how hydraulic permeability depends on pore fluid chemistry under different conditions. Coupling effects of pore water desalination and the effective stress enhancement on the hydraulic permeability of marine sediments surrounding a depressurization wellbore during hydrate production are discussed. Results and discussion show that the hydraulic permeability reduction is significant only when the electric double layer thickness is comparable to the characteristic pore size, and the reduction becomes more obvious when the ion mobility of the saline solution is smaller and the surface dielectric potential of clay minerals is lower. During gas hydrate production in the ocean, the salinity sensitivity of the hydraulic permeability could become either stronger and weaker, depending on whether the original characteristic pore size of marine sediments is relatively large or small.
Underwater Line Monitoring Using Optimally Placed Inclinometers
Authors: Jin Chungkuk , Hong Seong Hyeon
Published: October 2024

Underwater monitoring presents challenges related to maintaining a continuous power supply and communication, necessitating the use of a smaller number of sensors to effectively cover the entire line. An underwater line tracking method is proposed to evaluate global behaviors and stresses in real time. The method employs angles at several points on the line, as well as displacements and curvatures at both ends. In this method, any line displacement, angle, and curvature are expressed as Fourier series, and Fourier coefficients are obtained by utilizing sensor data. Then, the behavior of any line location is assessed. In addition, to reduce the number of sensors and improve accuracy, optimal inclinometer locations are determined by a genetic algorithm. The proposed line tracking algorithm was validated through two numerical examples; one with an inclined tunnel and one with a marine steel catenary riser attached to a Floating Production Storage and Offloading (FPSO) vessel. Through these examples, the proposed algorithm was proven to capture global behaviors accurately when optimally located sensors are used. In the riser monitoring case, the optimized sensor placement with eight intermediate sensors achieved an average mean distance error of 1.91 m, which is lower than the 2.65 m error obtained with ten intermediate sensors without optimization.
Four New Species of Deconica (Strophariaceae, Agaricales) from Subtropical Regions of China
Authors: Yan Jun-Qing , Wang Sheng-Nan , Hu Ya-Ping , Nie Cheng-Feng , Ke Bin-Rong , Zeng Zhi-Heng , Zeng Hui
Published: October 2024

Deconica is a relatively small genus, with only 90 names recorded in previous research. In this study, four new species of Deconica have been identified based on morphological and phylogenetic evidence from subtropical regions of China. This represents the first discovery of new species of Deconica in China. Morphologically, D. austrosinensis is characterized by medium-sized spores that are elliptical to elongated-ellipsoid in face view, and fusiform to sublageniform and slightly thick-walled pleurocystidia; D. furfuracea is identified by a well-developed and evanescent veil, medium-sized spores that are rhomboid to mitriform in face view, and fusiform to subclavate pleurocystidia that are rare and subacute at apex; D. fuscobrunnea is recognized by dark brown pileus, medium-sized spores that are rhomboid to mitriform in face view, an ixocutis pileipellis, lageniform cheilocystidia with a long neck and lacks pleurocystidia; D. ovispora is distinguished from other Deconica species by medium-sized spores that are ovoid in face view, an ixocutis pileipellis, lageniform cheilocystidia with a long to short neck, and lacks pleurocystidia. Their distinct taxonomic status is confirmed by the positions of the four new species in ITS + LSU phylogenetic trees. Detailed descriptions and morphological photographs of four new species are presented.
Unlocking Fungal Potential: The CRISPR-Cas System as a Strategy for Secondary Metabolite Discovery
Authors: Leal Karla , Rojas Edwind , Madariaga David , Contreras María José , Nuñez-Montero Kattia , Barrientos Leticia , Goméz-Espinoza Olman , Iturrieta-González Isabel
Published: October 2024

Natural products (NPs) are crucial for the development of novel antibiotics, anticancer agents, and immunosuppressants. To highlight the ability of fungi to produce structurally diverse NPs, this article focuses on the impact of genome mining and CRISPR-Cas9 technology in uncovering and manipulating the biosynthetic gene clusters (BGCs) responsible for NP synthesis. The CRISPR-Cas9 system, originally identified as a bacterial adaptive immune mechanism, has been adapted for precise genome editing in fungi, enabling targeted modifications, such as gene deletions, insertions, and transcription modulation, without altering the genomic sequence. This review elaborates on various CRISPR-Cas9 systems used in fungi, notably the Streptococcus pyogenes type II Cas9 system, and explores advancements in different Cas proteins for fungal genome editing. This review discusses the methodologies employed in CRISPR-Cas9 genome editing of fungi, including guide RNA design, delivery methods, and verification of edited strains. The application of CRISPR-Cas9 has led to enhanced production of secondary metabolites in filamentous fungi, showcasing the potential of this system in biotechnology, medical mycology, and plant pathology. Moreover, this article emphasizes the integration of multi-omics data (genomics, transcriptomics, proteomics, and metabolomics) to validate CRISPR-Cas9 editing effects in fungi. This comprehensive approach aids in understanding molecular changes, identifying off-target effects, and optimizing the editing protocols. Statistical and machine learning techniques are also crucial for analyzing multi-omics data, enabling the development of predictive models and identification of key molecular pathways affected by CRISPR-Cas9 editing. In conclusion, CRISPR-Cas9 technology is a powerful tool for exploring fungal NPs with the potential to accelerate the discovery of novel bioactive compounds. The integration of CRISPR-Cas9 with multi-omics approaches significantly enhances our ability to understand and manipulate fungal genomes for the production of valuable secondary metabolites and for promising new applications in medicine and industry.
Forest Enclave Potential Assessment for Nature Conservation and Recreation in City with Dysfunctional Natural System
Authors: Ćwik Agata , Wójcik Tomasz , Przydział Gabriela
Published: October 2024

Forests are an important component of the natural systems of large cities. Their deficiency limits the proper functioning of these systems and creates a shortage of recreational places for residents needing contact with nature. This can be encountered in Rzeszów, a city in southern Poland with 200,000 inhabitants, which is characterised by the smallest forest area (2.8%) of all province capitals in the country. The natural state of small forest enclaves in this city has not been fully investigated. This has led to incorrect management and nature conservation policies. Therefore, the aim of this research conducted since 2015 was to recognise the potential for conservation and recreational functions using the concept of ecosystem services (ES) and ecosystem disservices (EDS), and to develop recommendations for the optimal use of these areas. This article analyses and compares 14 indicators related to ES and EDS of three out of five larger forest patches in the city. The results of this analysis indicate that the current method for protecting these valuable elements of the natural system does not correspond with their actual conservation potential. The application of the ES and EDS concepts to assess the nature conservation potential allowed us to determine it as high in two forest enclaves where such potential had not been indicated so far, and to identify the highest recreational potential in one of the investigated sites.
Phonetic Diversity vs. Sociolinguistic and Phonological Patterning of R in Québec French
Authors: Hutin Mathilde , Lancien Mélanie
Published: October 2024

In this study, we investigate the multifaceted realizations of the /R/ consonant in Québec French (QF) by combining sociolinguistic and phonological approaches. First, from a sociophonetic point of view, we utilize a mixed-effects multinomial logistic regression model to analyze the impact of various variables on the distribution of /R/ variants. Our analysis of location, birth year and gender reveals that each variable and its interactions significantly influence the distribution of /R/ variants. We identify three distinct speaker groups based on their preferences for these variants: those favoring apical variants, those using uvular trills, and those employing neither apical nor uvular trills (mostly using fricatives and their approximantized or vocalized variants). From a phonological point of view, we show that the use of the /R/ variants among the three groups correlates with syllabic position, with weaker variants displayed in so-called “weakening” contexts, such as coda and intervocalic onset. Our results thus show that the apparent diversity of /R/ realizations in QF actually follows a pattern from both a sociolinguistic and a formal phonological point of view.
In-Depth Phytochemical Profile by LC-MS/MS, Mineral Content by ICP-MS, and In-Vitro Antioxidant, Antidiabetic, Antiepilepsy, Anticholinergic, and Antiglaucoma Properties of Bitlis Propolis
Authors: İzol Ebubekir , Turhan Münire
Published: October 2024

Propolis is very significant in terms of its phytochemical content and biological activity among bee products. In this study, the antioxidant activities (total phenolic and flavonoid, Fe3+, Cu2+ (CUPRAC), Fe3+-TPTZ (FRAP) reducing, and DPPH•, ABTS•+ scavenging assays) of propolis collected from the Bitlis province of Türkiye were determined. In addition, the carbonic anhydrase I and II isoenzymes (hCA I and hCA II), α-glycosidase, acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) inhibition activity and phytochemical profile of propolis and mineral content were determined by LC-MS/MS and ICP-MS, respectively. In propolis, 31 phytochemicals were found, and the highest concentration of acacetin (23.604 mg/g) was detected. It is seen that the phytochemicals in propolis provide antioxidant properties. The mineral content was screened for 18 elements and determined to be rich in the elements that make up the salt content. Total phenolic content was 215.14 mg GAE/g, and total flavonoid content was 79.11 mg QE/g. The Fe3+ reduction result was 0.940 (µg/mL), CUPRAC 1.183 (µg/mL), FRAP 0.963 (µg/mL), DPPH• scavenging IC50: 16.7 (µg/mL), and ABTS IC50: 8.01 (µg/mL). hCA I enzyme inhibition results in IC50: 7.19 (µg/mL), hCA II 8.15, AChE 5.17, BChE 7.50, and α-Glycosidase 5.72. As a result of this study, it was determined that Bitlis propolis has high antioxidant properties and a rich phytochemical content. It was also observed that it is an effective enzyme inhibitor against epilepsy, glaucoma, Alzheimer’s, and diabetes, which are important diseases, and it can be evaluated in the treatment of these diseases and drug production.
2α-Methyl-5α-androstan-17β-ol-3-one-17β-heptanoate
Authors: Turza Alexandru , Muresan-Pop Marieta , Miclaus Maria-Olimpia , Borodi Gheorghe
Published: October 2024

Drostanolone is a popular synthetic dihydrotestosterone derivative and an anabolic–androgenic agent which belongs to the steroid class. The crystal structure of a new polymorph of the esterified prodrug of drostanolone, namely drostanolone enanthate, was elucidated using single crystal X-ray diffraction. Furthermore, it was analyzed using the thermal DTA/TGA technique and FT-IR spectroscopy.
The Shielding Effect of Phenyl Groups in the Silyl-Protecting Groups Introduced into Borneol and Isoborneol
Authors: Lyu Baohe , Sugiura Mio , Tayama Koya , Hiraga Yoshikazu , Takagi Ryukichi , Niwayama Satomi
Published: October 2024

Protection of the hydroxy group in monoterpenoids borneol and isoborneol with various silyl-protective groups containing a different number of phenyl groups enabled complete assignments of the 1H chemical shifts. In particular, a wider range of the protons in isoborneol and its silyl-protected derivatives were influenced than those in borneol and its silyl-protected derivatives, which is likely to be due to the anisotropic effects from the phenyl groups. Understanding these effects allows for the interpretation of the 1H NMR spectra and provides information about how silyl-protecting groups affect these spectra.
Investigation of Structural Phase, Mechanical, and Tribological Characteristics of Layer Gradient Heat-Protective Coatings Obtained by the Detonation Spraying Method
Authors: Buitkenov Dastan , Rakhadilov Bauyrzhan , Nabioldina Aiym , Mukazhanov Yerkat , Adilkanova Meruert , Raisov Nurmakhanbet
Published: October 2024

This paper presents the results of a study of layer gradient thermal protection coatings based on NiCrAlY and YSZ obtained by detonation spraying. Modern gas turbines and high-temperature units operate under extreme temperatures and aggressive environments, which requires effective protection of components from wear, corrosion, and thermal shocks. In this study, the use of layer gradient coatings consisting of alternating layers of NiCrAlY and YSZ was investigated with the aim of solving the problem of thermal stress accumulation due to a smooth change in the composition of the layers. Microstructural and phase analysis showed that alternating layers of NiCrAlY and YSZ formed a dense layer gradient structure with clear interphase boundaries and low porosity. Detonation spraying led to a complete transformation of the monoclinic ZrO2 phase into a tetragonal one, which significantly increased the mechanical strength of the coating and its resistance to thermal shocks. Sample 1D1 demonstrated excellent tribological and corrosion properties in a 3.5% NaCl solution, which can be explained by its higher density and reduced number of pores. Mechanical tests revealed stable values of hardness and wear resistance of the coating, especially for the 1D1 coating. Studies have shown that coatings are resistant to thermal shocks, but thicker layers show a tendency to peel off after thermal cycling. The obtained results indicate high prospects for the use of layer gradient coatings based on NiCrAlY and YSZ for the protection of gas turbine components and other high-temperature installations operating under extreme loads and aggressive environments.
Effect of the Intaglio Surface Treatment and Thickness of Different Types of Yttria-Stabilized Tetragonal Zirconia Polycrystalline Materials on the Flexural Strength: In-Vitro Study
Authors: Almirabi Razan S. , Alzahrani Khaled M.
Published: October 2024

Background: Surface treatment of the intaglio surface of zirconia is important for bonding. However, it could affect the strength of the materials. The purpose of this study is to compare the effect of laser, etching, and air abrasion surface treatment methods to a control group on the flexural strength of three zirconia materials with two different thicknesses. (1) Methods: A total of 120 disks were divided into three groups according to the type of zirconia and the ceramic thickness. Then, according to the surface treatment method, the groups were divided into four subdivisions. The change in the microstructure of the ceramic material was investigated through Scanning Electron Microscope (EVO LS10, Carl Zeiss SMT Ltd. Oberkochen, Germany). Phase identification was performed using an X-ray diffraction device (XRD; Ultimate IV X-ray Diffractometer, Rigaku Inc., Tokyo, Japan). The flexural strength was assessed with a biaxial flexural strength test in a universal testing machine. Data were analyzed using SPSS Software (SPSS version 26.0.Armonk, NY: IBM Corp). A three-way ANOVA and a post hoc Dunnett T3 test were employed to evaluate the effect of the yttria concentration, thickness, and surface treatment on the flexural strength of zirconia (α = 0.05). (2) Results: At 0.8 mm thickness, air abrasion significantly increased the flexural strength of 3Y-TZP (1130.6 ± 171.3 MPa) and 4Y-TZP (872 ± 108.6 MPa). However, air abrasion significantly decreased the flexural strength of 5Y-TZP materials (373 ± 46.8 MPa). Laser irradiation significantly decreased the flexural strength of 5Y-TZP (347 ± 50.3 MPa), while etching significantly decreased the flexural strength of both 3Y-TZP (530 ± 48.8) and 4Y-TZP (457.1 ± 57.3). When the thickness increased to 1 mm, air abrasion continued to significantly decrease the flexural strength of 5Y-TZP materials. (3) Conclusions: There was a negative effect of surface treatment on the flexural strength at 0.8 mm thickness rather than at 1 mm thickness. Air abrasion enhances the flexural strength of 3Y-TZP and 4Y-TZP materials but significantly reduces the flexural strength of 5Y-TZP materials. Zircos-E etching and Er:YAG surface treatment methods did not significantly reduce the flexural strength of 5Y-TZP materials at 1 mm thickness and can be recommended as an alternative surface treatment for 5Y-TZP materials.
Evaluation of 3-Point and 4-Point Bending Tests for Tensile Strength Assessment of GFRP Bars
Authors: Lochan Philip Prakash , Polak Maria Anna
Published: October 2024

Glass Fiber Reinforced Polymer (GFRP) bars are used as reinforcement for structural concrete, especially in cases where corrosion of traditional steel reinforcement is a problem. The tensile strength of these reinforcing bars is the primary characteristic on which the design of concrete members reinforced with GFRP bars relies. Determination of the tensile strength of the bars using a direct tensile test is a time and resource-intensive task and therefore is not routinely conducted for quality control. The tensile strength can also be measured from flexure tests, which are much simpler than direct tensile tests, and use appropriate correlation formulations. In this paper, the applicability of flexure testing for the identification of bars’ tensile strength is investigated by conducting and analyzing both 3-point and 4-point flexure testing. The correlation formulations are presented that allow the determination of tensile strength from the modulus of rupture. The Weibull weakest link model and the assumption of the same flaw distribution in tensile and flexure tests is adopted. The results of the 3-point and the 4-point bending are presented and compared. Comparisons are also conducted to select direct tensile test results. The work shows that 3-point and 4-point bending tests provide very similar results, with the difference between the results being 2% to 10%, suggesting both tests can be used for tensile strength determination of GFRP bars.
Deep Learning-Based Microscopic Damage Assessment of Fiber-Reinforced Polymer Composites
Authors: Azad Muhammad Muzammil , Shah Atta ur Rehman , Prabhakar M. N. , Kim Heung Soo
Published: October 2024

Fiber-reinforced polymers (FRPs) are increasingly being used as substitutes for traditional metallic materials across various industries due to their exceptional strength-to-weight ratio. However, their orthotropic properties make them prone to multiple forms of damage, posing significant challenges in their design and application. During the design process, FRPs are subjected to various loading conditions to study their microscopic damage behavior, typically assessed through scanning electron microscopy (SEM). While SEM provides detailed insights into fracture surfaces, the manual analysis of these images is labor-intensive, time-consuming, and subject to variability based on the observer’s expertise. To address these limitations, this research proposes a deep learning-based approach for the autonomous microscopic damage assessment of FRPs. Several computationally efficient pre-trained deep learning models, such as DenseNet121, NasNet Mobile, EfficientNet, and MobileNet, were evaluated for their performance in identifying different damage modes autonomously, thus reducing the need for manual interpretation. SEM images of FRPs with five distinct failure modes were used to validate the proposed method. These failure modes include three fiber-based failures such as fiber breakage, fiber pullout, and mixed-mode failure, and two matrix-based failures such as matrix brittle failure and matrix ductile failure. The entire dataset is divided into train, validation, and test sets. Deep learning models were established by training on train and validation sets for five failure modes, while the test set was used as the unseen data to validate the models. The models were assessed using various evaluation metrics on an unseen test dataset. Results indicate that the EfficientNet model achieved the highest accuracy of 97.75% in classifying the failure modes. The findings demonstrate the effectiveness of employing deep learning techniques for microscopic damage assessment, offering a more efficient, consistent, and scalable solution compared to traditional manual analysis.
Fractional-Order Modeling of COVID-19 Transmission Dynamics: A Study on Vaccine Immunization Failure
Authors: Qiao Yan , Ding Yuhao , Pang Denghao , Wang Bei , Lu Tao
Published: October 2024

COVID-19 is an enveloped virus with a single-stranded RNA genome. The surface of the virus contains spike proteins, which enable the virus to attach to host cells and enter the interior of the cells. After entering the cell, the virus exploits the host cell’s mechanisms for replication and dissemination. Since the end of 2019, COVID-19 has spread rapidly around the world, leading to a large-scale epidemic. In response to the COVID-19 pandemic, the global scientific community quickly launched vaccine research and development. Vaccination is regarded as a crucial strategy for controlling viral transmission and mitigating severe cases. In this paper, we propose a novel mathematical model for COVID-19 infection incorporating vaccine-induced immunization failure. As a cornerstone of infectious disease prevention measures, vaccination stands as the most effective and efficient strategy for curtailing disease transmission. Nevertheless, even with vaccination, the occurrence of vaccine immunization failure is not uncommon. This necessitates a comprehensive understanding and consideration of vaccine effectiveness in epidemiological models and public health strategies. In this paper, the basic regeneration number is calculated by the next generation matrix method, and the local and global asymptotic stability of disease-free equilibrium point and endemic equilibrium point are proven by methods such as the Routh–Hurwitz criterion and Lyapunov functions. Additionally, we conduct fractional-order numerical simulations to verify that order 0.86 provides the best fit with COVID-19 data. This study sheds light on the roles of immunization failure and fractional-order control.
Mathematical Model to Study the Effect of Refuge on Cannibalism in Atractosteus tropicus
Authors: Sepúlveda-Quiroz César Antonio , Valenzuela Luis Miguel , Blé Gamaliel , Martínez-García Rafael , Álvarez-González Carlos Alfonso , López-Molina Antioco
Published: October 2024

Cannibalism is a behavior that different species of fish exhibit in the early stages of their life, and it has been widely reported. In Tabasco, Mexico, the ancestral species Atractosteus tropicus is farmed, which is a freshwater fish with a high nutritional and economic value. This species exhibits high cannibalistic behavior both in its larval and juvenile stages, which considerably decreases its production. Therefore, strategies have been developed to mitigate the effects of this behavior. One of them is the placement of shelters (rocks and artificial vegetation), which allow the vulnerable population to protect themselves from cannibals. The goal of this work is to study the effect of shelters on the cannibalistic behavior of the A. tropicus population through a mathematical model. The population is divided into two classes, the vulnerable population (prey) and the cannibal population (predator). Moreover, a system of ordinary differential equations is established, which is analyzed, and sufficient conditions for the coexistence of the two species are shown. Numerical simulations show coexistence by varying levels of refuge. The results obtained in this work can be applied to other populations that exhibit cannibalistic behavior.
A Look at Generalized Trigonometric Functions as Functions of Their Two Parameters and Further New Properties
Authors: Karp Dmitrii , Prilepkina Elena
Published: October 2024

Investigation of the generalized trigonometric and hyperbolic functions containing two parameters has been a very active research area over the last decade. We believe, however, that their monotonicity and convexity properties with respect to parameters have not been thoroughly studied. In this paper, we make an attempt to fill this gap. Our results are not complete; for some functions, we manage to establish (log)-convexity/concavity in parameters, while for others, we only managed the prove monotonicity, in which case we present necessary and sufficient conditions for convexity/concavity. In the course of the investigation, we found two hypergeometric representations for the generalized cosine and hyperbolic cosine functions which appear to be new. In the last section of the paper, we present four explicit integral evaluations of combinations of generalized trigonometric/hyperbolic functions in terms of hypergeometric functions.
A Bimodal Exponential Regression Model for Analyzing Dengue Fever Case Rates in the Federal District of Brazil
Authors: da Costa Nicollas S. S. , Lima Maria do Carmo Soares de , Cordeiro Gauss Moutinho
Published: October 2024

Dengue fever remains a significant epidemiological challenge globally, particularly in Brazil, where recurring outbreaks strain healthcare systems. Traditional statistical models often struggle to accurately capture the complexities of dengue case distributions, especially when data exhibit bimodal patterns. This study introduces a novel bimodal regression model based on the log-generalized odd log-logistic exponential distribution, offering enhanced flexibility and precision for analyzing epidemiological data. By effectively addressing multimodal distributions, the proposed model overcomes the limitations of unimodal models, making it well suited for public health applications. Through regression analysis of dengue case data from the Federal District of Brazil during the epidemiological weeks of 2022, the model demonstrates its capacity to improve the fit of the disease rate. The model’s parameters are estimated using maximum likelihood estimation, and Monte Carlo simulations validate their accuracy. Additionally, local influence measures and residual analysis ensure the proposed model’s goodness-of-fit. While this innovative regression model offers substantial advantages, its effectiveness depends on the availability of high-quality data, and further validation is necessary to confirm its applicability across diverse diseases and regions with varying epidemiological characteristics.
Fucoidan from Undaria pinnatifida Enhances Exercise Performance and Increases the Abundance of Beneficial Gut Bacteria in Mice
Authors: Yang Cheng , Dwan Corinna , Wimmer Barbara C. , Wilson Richard , Johnson Luke , Caruso Vanni
Published: October 2024

Fucoidans, known for their diverse biological properties such as anti-inflammatory, antiviral, antitumor, and immune stimulatory effects, have recently gained attention for their potential benefits in exercise endurance, muscle mass, and anti-fatigue. However, the mechanisms by which fucoidans enhance exercise performance are still unclear. To investigate these effects, we administered 400 mg/kg/day of fucoidan extract derived from Undaria pinnatifida to 64 C57BL/6J mice over 10 weeks. We evaluated changes in running activity, mitochondrial-related gene expression in skeletal muscle, and alterations in the intestinal microbiome. Our results showed that fucoidan supplementation significantly increased daily running distance and muscle mass by 25.5% and 10.4%, respectively, in mice on a standard chow diet, and with more modest effects observed in those on a high-fat diet (HFD). Additionally, fucoidan supplementation led to a significant increase in beneficial gut bacteria, including Bacteroides/Prevotella, Akkermansia muciniphila, and Lactobacillus, along with a notable reduction in the Firmicutes/Bacteroidetes ratio, indicating improved gut microbiome health. Mechanistically, fucoidan supplementation upregulated the mRNA expression of key genes related to mitochondrial biogenesis and oxidative capacity, such as COX4, MYH1, PGC-1α, PPAR-γ, and IGF1, in both standard chow and HFD-fed mice. Our findings suggest that fucoidan supplementation enhances exercise performance, improves muscle function, and positively modulates the gut microbiome in mice, regardless of diet. These effects may be attributed to fucoidans’ potential prebiotic role, promoting the abundance of beneficial gut bacteria and contributing to enhanced exercise performance, increased muscle strength, and improved recovery.
Incorporation of Silver into Sulfate Groups Enhances Antimicrobial and Antiviral Effects of Fucoidan
Authors: Iwata Akira , Yamamoto-Fujimura Mayuko , Fujiwara Suzuka , Tajima Saya , Shigeyama Takahide , Tsukimoto Moriya , Ibuki Tatsuya , Kataoka-Kato Akito
Published: October 2024

The COVID-19 pandemic has significantly impacted our daily lives. Routine infection-control measures present an effective preventive strategy for a new infectious disease outbreak. Fucoidan, a fucose-rich sulfated polysaccharide found in brown algae, exhibits antiviral activity. Moreover, fucoidan exerts an antimicrobial effect; however, it requires considerably higher concentrations than those needed for its antiviral effect. In this study, we aimed to enhance the antimicrobial activity of fucoidan and prepared a fucoidan silver salt (Ag-Fuc) by incorporating silver ions into the sulfate groups of Yakult Fucoidan derived from Cladosiphon okamuranus Tokida. The fucoidan exhibited a weak inhibitory effect on Escherichia coli growth at significantly higher concentrations, whereas Ag-Fuc inhibited the growth of E. coli and Staphylococcus epidermidis at concentrations comparable to those required for its antiviral effects. Moreover, Ag-Fuc inhibited the growth of Cladosporium cladosporioides. Infections of human cells with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza A virus were more effectively inhibited by lower concentrations of Ag-Fuc compared with fucoidan. Overall, silver ions added to the sulfate groups induced strong antimicrobial activity and enhanced the antiviral effect of fucoidan. We suggest a wide application of Ag-Fuc as a routine preventive material to avoid new infectious disease pandemics.
Small Punch Test to Estimate the Threshold Stress in Aggressive Environments by Incremental Step Loading
Authors: Arroyo Borja , Andrea Laura , Álvarez José A. , Cicero Sergio , Gutiérrez-Solana Federico , Abarca Luis
Published: October 2024

The present work is a relevant advance in the validation of the incremental step loading technique (ASTM F1624 standard) when applied to Small Punch tests (SPT) for the threshold load determination of medium- and high-strength steels in aggressive environments, as a novel alternative to conventional time-consuming tests under constant load. It completes previous works by the authors on this topic, extending a methodology to estimate the threshold stress from SPT tests in aggressive environments, covering the whole range of hardness marked by ASTM F1624 as the main goal. This is achieved by calibrating a model of the material’s hardness by the use of a coefficient in function of it. For this purpose, four medium- and high-strength steels of 33, 35, 50 and 60 HRC (Hardness Rockwell C) are exposed to three different cathodic polarization hydrogen embrittlement environments of 1, 5 and 10 mA/cm2 in 1N H2SO4 acid electrolyte connected to a platinum anode. Threshold stresses in these circumstances are obtained by uniaxial specimens following ASTM F1624 and compared to their homologous threshold loads obtained by Small Punch tests according to the authors’ original methodology proposal. Finally, the aforementioned model, consisting of a correlation based on composing an elastic and a plastic part, is calibrated for a hardness ranging 33–60 HRC, this being the main original contribution of this work; the elastic part is dependent just on the elastic-to-plastic transition SPT load, while the plastic part is ruled by a material hardness-dependent coefficient. This technique supposes an advance in engineering tools, due to its applicability in situations of material shortage, such as in-service components, welded joints, local areas, complex geometries, small thicknesses, etc., often present in aerospace, automotive or oil–gas, among others.
Dynamic Acoustic Holography: One-Shot High-Precision and High-Information Methodology
Authors: Li Zhaoxi , Yang Yiheng , Lu Qi , Wei Xiongwei , Hou Chenxue , Quan Yi , Lü Xiaozhou , Bao Weimin , Yang Yintang , Fei Chunlong
Published: October 2024

Acoustic holography technology is widely used in the field of ultrasound due to its capability to achieve complex acoustic fields. The traditional acoustic holography method based on single-phase holograms is limited due to its inability to complete acoustic field control with high dynamics and accuracy. Here, we propose a method for constructing an acoustic holographic model, introducing an ultrasonic array to provide dynamic amplitude control degrees of freedom, and combining the dynamically controllable ultrasonic array and high-precision acoustic hologram to achieve the highest acoustic field accuracy and dynamic range. This simulation method has been proven to be applicable to both simple linear patterns and complex surface patterns. Moreover, it is possible to reconstruct the degree of freedom of the target plane amplitude effectively and achieve a breakthrough in high information content. This high-efficiency acoustic field control capability has potential applications in ultrasound imaging, acoustic tweezers, and neuromodulation.
Recent Advances of PDMS In Vitro Biomodels for Flow Visualizations and Measurements: From Macro to Nanoscale Applications
Authors: Souza Andrews , Nobrega Glauco , Neves Lucas B. , Barbosa Filipe , Ribeiro João , Ferrera Conrado , Lima Rui A.
Published: October 2024

Polydimethylsiloxane (PDMS) has become a popular material in microfluidic and macroscale in vitro models due to its elastomeric properties and versatility. PDMS-based biomodels are widely used in blood flow studies, offering a platform for improving flow models and validating numerical simulations. This review highlights recent advances in bioflow studies conducted using both PDMS microfluidic devices and macroscale biomodels, particularly in replicating physiological environments. PDMS microchannels are used in studies of blood cell deformation under confined conditions, demonstrating the potential to distinguish between healthy and diseased cells. PDMS also plays a critical role in fabricating arterial models from real medical images, including pathological conditions such as aneurysms. Cutting-edge applications, such as nanofluid hemodynamic studies and nanoparticle drug delivery in organ-on-a-chip platforms, represent the latest developments in PDMS research. In addition to these applications, this review critically discusses PDMS properties, fabrication methods, and its expanding role in micro- and nanoscale flow studies.
Feline Vector-Borne Diseases and Their Possible Association with Hematological Abnormalities in Cats from Midwestern Brazil
Authors: Carvalho Stephani Félix , Pádua Gracielle Teles , Paula Warley Vieira de Freitas , Tavares Mariana Avelar , Neves Lucianne Cardoso , Pereira Brenda Gomes , Santos Rayane Almeida , dos Santos Gabriel Cândido , Cardoso Ennya Rafaella Neves , Qualhato Andriele Ferreira , Bittencourt Raphaela Bueno Mendes , de Lima Nicolas Jalowitzki , Martins Danieli Brolo , Dantas-Torres Filipe , Krawczak Felipe da Silva
Published: October 2024

Among the parasitic and infectious diseases affecting cats, those caused by vector-borne pathogens deserve attention due to their ability to cause nonspecific clinical signs and clinicopathological abnormalities. We studied the presence of Cytauxzoon spp., Ehrlichia spp., and Mycoplasma spp. in blood samples from 135 cats referred to the veterinary teaching hospital of the Federal University of Goiás in midwestern Brazil. We also investigated co-infections with Feline Immunodeficiency Virus (FIV) and Feline Leukemia Virus (FeLV) as well as the correlation between Mycoplasma spp. infection and cat variables, including age, sex, breed, and complete blood count abnormalities. Upon PCR testing, 20.7% (28/135) of samples were positive for Mycoplasma spp., 1.5% (2/135) for Cytauxzoon spp., and none for Ehrlichia spp. Co-infections with Mycoplasma spp. and Cytauxzoon spp. were detected in the two cats with the latter infection. Mycoplasma spp. infection was statistically associated with the simultaneous presence of thrombocytopenia and leukocytosis. This study confirms a high frequence of Mycoplasma spp. infection, with both M. haemofelis and ‘Candidatus Mycoplasma haemominutum’ circulating in this cat population. The clinical significance of Mycoplasma spp. infection in cats should be further explored and this infection should eventually be included in the differential diagnosis of thrombocytopenia and leukocytosis in otherwise apparently healthy cats.
Aging-Induced Changes in Cutibacterium acnes and Their Effects on Skin Elasticity and Wrinkle Formation
Authors: Jung YeonGyun , Kim Ikwhan , Jung Da-Ryung , Ha Ji Hoon , Lee Eun Kyung , Kim Jin Mo , Kim Jin Young , Jang Jun-Hwan , Bae Jun-Tae , Shin Jae-Ho , Cho Yoon Soo
Published: October 2024

Skin aging involves biomechanical changes like decreased elasticity, increased wrinkle formation, and altered barrier function. The skin microbiome significantly impacts this process. Here, we investigated the effects of decreased Cutibacterium acnes abundance and increase in other skin microorganisms on skin biomechanical properties in 60 healthy Koreans from Seoul, divided into younger (20–29 years) and older (60–75 years) groups. Metagenomic sequencing and skin assessments showed that the older group exhibited decreased C. acnes dominance and increased microbial diversity, correlating with reduced skin elasticity and increased wrinkles. In the younger age group, the enriched pathways included zeatin biosynthesis, distinct biotin metabolism pathways, and cofactor and vitamin metabolism in the younger age group, whereas pathways related to lipid metabolism, energy metabolism, and responses to environmental stressors, including UV damage and pollution, were enriched in the older group, according to functional analysis results. Network analysis indicated higher microbial connectivity in the younger group, suggesting a more stable community, whereas the older group’s community displayed higher modularity, indicating more independent and specialized clusters. This study enhances our understanding of the impact of skin microbiome changes on skin aging, particularly the anti-aging effects of C. acnes. Future research should focus on the physiological mechanisms of skin microbiota on skin aging and explore therapeutic potentials to enhance skin health.