bluuebunny/crossref_metadata_2025 huggingface dataset:
Ocular Involvement of Granulomatosis with Polyangiitis
Authors: Byszewska Anna , Skrzypiec Izabela , Rymarz Aleksandra , Niemczyk Stanisław , Rękas Marek
Published: July 2023

Granulomatosis with polyangiitis (GPA), formerly referred to as Wegener’s disease, is a form of ANCA-associated vasculitis. It manifests mainly in the kidneys and the upper respiratory tract, but ocular involvement is not uncommon. In this article, four cases with ocular manifestations are presented with comprehensive photographic documentation. We describe the way to proper diagnosis, which may be long, the possible treatment, and the final outcomes. Our patients had the following ocular manifestations of GPA: retinal vasculitis, anterior necrotizing scleritis, medial orbital wall and orbital floor erosion with middle face deformation, compressive optic neuropathy due to retrobulbar inflammatory mass, and the abscess of the eyelids, inflammatory intraorbital mass causing exophthalmos and diplopia. This manuscript includes the description of severe forms of GPA, the initial signs and symptoms, relapses, and difficulties in achieving remission. The extraocular involvement is described with diagnostic modalities and laboratory findings. One of the reported cases was diagnosed by an ophthalmologist on the basis of ocular symptoms in the early stages of the disease. Our outcomes are compared with those discussed in the literature.
Ultrasonographic Prenatal Diagnosis: Unveiling the Path to Improved Antenatal Care
Authors: Granese Roberta , Gulino Ferdinando Antonio , Incognito Giosuè Giordano , Cianci Stefano , Martinelli Canio , Ercoli Alfredo
Published: July 2023

The realm of prenatal diagnosis has witnessed remarkable advancements in recent years, primarily due to the widespread use of ultrasonography [...]
Oral Health Screening for Risk Reduction for Early Periprosthetic Joint Infections of Hip and Knee Endoprostheses—Results of a Prospective Cohort Study
Authors: Fenske Fabian , Krause Leah , Meyer Stephan , Kujat Benjamin , Repmann Jacqueline , Neuhaus Michael , Zimmerer Rüdiger , Roth Andreas , Lethaus Bernd , Ziebolz Dirk , Schmalz Gerhard
Published: July 2023

This prospective observational study had two aims: (I) to assess whether a preoperative dental screening before endoprosthesis (EP) implantation with need-based dental intervention would decrease the prevalence of periprosthetic joint infection (PJI) and (II) to evaluate whether instructed orthopedic surgeons would achieve similar results in oral screening as dentists. The preoperative oral health statuses of the patients, prior to EP insertion, were either evaluated by the patients’ general dentists (Ia) or, if the patient had not visited a general dentist, by an instructed orthopedic surgeon (Ib). Both the dentist and orthopedic surgeon used standardized risk estimation (low risk, moderate risk, and high risk) for an oral-health-related infectious complication after EP insertion, including a recommendation for further management of the patient. If required, a need-based dental rehabilitation was performed. In addition, retrospective data evaluation of a comparison group (II) was performed, which had not been screened orally preoperatively. A total of 777 patients (screening group (I): n = 402, of which 229 were screened by a dentist (Ia), 173 were screened by an orthopedic surgeon (Ib); comparison group (II): n = 375) were included. No general association between early infection rate and preoperative oral screening in general was found (1% PJI in screening group (I), 1.6% PJI in comparison group (II); p = 0.455). However, screening performance (dentist vs. orthopedic surgeon) had a significant impact on the prevalence of developed PJIs (p = 0.021). Thereby, 100% of observed infections in the screening group (I) occurred in the group with previous oral screening by an orthopedic surgeon (Ib). Furthermore, the C-reactive protein (CRP) value at discharge was significantly lower when general preoperative oral screening had been performed (group I vs. group II, p = 0.03). Only preoperative oral screening by a dentist had the potential to reduce oral-focus-associated EP infections; therefore, increased attention should be paid to the further promotion of interdisciplinary work between dentists and orthopedic surgeons. Dental screenings, using objectifiable criteria, as applied in this study, seem reasonable but require further validation in larger cohorts.
Metabolic Flexibility and Inflexibility: Pathology Underlying Metabolism Dysfunction
Authors: Shoemaker Marni E. , Gillen Zachary M. , Fukuda David H. , Cramer Joel T.
Published: July 2023

Metabolic flexibility can be defined as the ability of the skeletal muscle to adjust its utilization of substrate pathways [...]
Flexural Behavior of Biocompatible High-Performance Polymer Composites for CAD/CAM Dentistry
Authors: Yeslam Hanin E.
Published: July 2023

High-performance polymeric materials have been used in computer-assisted design/ computer-assisted milling (CAD/CAM) dental restorative treatments due to their favorable esthetics as well as their mechanical and biological properties. Biocompatible poly-ether-ether-ketone (PEEK) and glass-fiber-reinforced composite techno-polymer (FRC) resins reportedly possess good flexural and shock absorption properties. However, intraoral thermal fluctuations may adversely affect them. This study aimed to investigate the flexural strength and effect of thermal aging on two commercially available high-performance polymers intended for CAD/CAM milled frameworks for definitive restorations. A total of 20 bar specimens were prepared using two CAD/CAM materials (n = 10); PEEK(P) and Bioloren FRC(F). Specimens from each material group were randomly divided into two sub-groups (n = 5): before aging (uP and uF) and after aging, with 10,000 thermocycles (5–55 °C) (aP and aF). All specimens were subjected to a three-point bending test in a universal testing machine. Flexural strength (Fs) values were calculated for all specimens, and their means were statistically analyzed using a t-test, and a general linear model (GLM) repeated measure ANOVA (p < 0.05). There was a statistically significant decrease in the Fs of (F) materials after aging (p = 0.03). (F) specimens exhibited significantly higher Fs than (P) before and after aging (p < 0.001). This type of material had a significant effect on Fs (p < 0.001). Within the limitations of this study, both materials exceeded the ISO recommendations of dental resins for flexural strength. However, FRC materials may benefit CAD/CAM milled long-span fixed partial dentures and implant-supported denture frameworks.
The Effect of Salinity on the Strength Behavior of Hydrate-Bearing Sands
Authors: Shen Shi , Wang Lei , Ge Yang , Chu Jiawei , Liang Huiyong
Published: July 2023

The first prerequisite for the efficient and safe exploitation of gas hydrate resources is to accurately analyze the primary mechanical performance of hydrate-bearing sediments (HBSs). The mechanical performance of HBSs is complex and affected by many factors, including the reservoir environment in situ (temperature, pore pressure, salinity). Several published studies have demonstrated a correlation of the mechanical behavior of hydrates with temperature and pressure (T-PP). However, the research on the effect of salinity on the mechanical properties of hydrates or HBSs is still a relatively blank field. This study found that the strength of HBSs decreased with increasing salinity. This phenomenon can be attributed to the influence of salinity on the phase equilibrium state of hydrates. NaCl changed the relationship between the phase equilibrium curve of the hydrate and the T-PP conditions. The distance between the T-PP conditions and equilibrium curve was reduced with increasing salinity, which in turn led to a decline in sample strength. Moreover, the effect of the phase equilibrium of hydrates on the mechanical performance of HBSs was further explored. NaCl was added to HBSs to regulate the phase equilibrium state of the hydrate. When the T-PP conditions were on the phase equilibrium curve, the strength behaviors of HBSs showed a high degree of consistency.
Short-Term Prediction of Global Sea Surface Temperature Using Deep Learning Networks
Authors: Xu Tianliang , Zhou Zhiquan , Li Yingchun , Wang Chenxu , Liu Ying , Rong Tian
Published: July 2023

The trend of global Sea Surface Temperature (SST) has attracted widespread attention in several ocean-related fields such as global warming, marine environmental protection and marine biodiversity. Sea surface temperature is influenced by climate change; with the accumulation of data from ocean remote sensing observations year by year, many scholars have started to use deep learning methods for SST prediction. In this paper, we use a dynamic region partitioning approach to process ocean big data and design a framework applied to a global SST short-term prediction system. On the architecture of a Long Short-Term Memory (LSTM) network, two deep learning multi-region SST prediction models are proposed, which extract temporal and spatial information of SST by encoding, using feature transformation and decoding to predict future multi-step states. The models are tested using OISST data and the model performance is evaluated by different metrics. The proposed MR-EDLSTM model and MR-EDConvLSTM model obtained the best results for short-term prediction, with RMSE ranging from 0.2712 °C to 0.6487 °C and prediction accuracies ranging from 97.60% to 98.81% for ten consecutive days of prediction. The results show that the proposed MR-EDLSTM model has better prediction performance in coastal areas, while the MR-EDConvLSTM model performs better in predicting the sea area near the equator. In addition, the proposed deep learning model has a smaller RMSE compared to the forecasting system based on the ocean model, indicating that the deep learning method has certain advantages in predicting global SST.
Emerging Trends in the Application of Green Synthesized Biocompatible ZnO Nanoparticles for Translational Paradigm in Cancer Therapy
Authors: Naser Shaikh Sheeran , Ghosh Basab , Simnani Faizan Zarreen , Singh Dibyangshee , Choudhury Anmol , Nandi Aditya , Sinha Adrija , Jha Ealisha , Panda Pritam Kumar , Suar Mrutyunjay , Verma Suresh K.
Published: July 2023

Zinc oxide nanomaterials have been the cynosure of this decade because of their immense potential in different biomedical applications. It includes their usage in the prognosis and treatment of different infectious and cellular diseases, owing to their peculiar physiochemical properties such as variable shape, size, and surface charge etc. Increasing demand and usage of the ZnO nanomaterials raise concerns about their cellular and molecular toxicity and their biocompatibility with human cells. This review comprehensively details their physiochemical properties for usage in biomedical applications. Furthermore, the toxicological concerns of ZnO nanomaterials with different types of cellular systems have been reviewed. Moreover, the biomedical and biocompatible efficacy of ZnO nanomaterials for cancer specific pathways has been discussed. This review offers insights into the current scenario of ZnO nanomaterials usage and signifies their potential future extension usage on different types of biomedical and environmental applications.
Comparison of the Micronaut-AM System and the EUCAST Broth Microdilution Reference Method for MIC Determination of Four Antifungals against Aspergillus fumigatus
Authors: Gyurtane Szabo Nikolett , Joste Valentin , Houzé Sandrine , Dannaoui Eric , Bonnal Christine
Published: July 2023

The Antifungal Susceptibility Testing method of the European Committee on Antimicrobial Susceptibility Testing (EUCAST-AFST) is a reference technique for the determination of the Minimum Inhibitory Concentration (MIC) of antifungals for Aspergillus fumigatus. However, it is time-consuming and requires expertise. Micronaut-AM (M-AM) is a fast, simple, time-saving, and ready-to-use new colorimetric method using an indicator (resazurin) to facilitate the visual reading. The aim of this retrospective study was to evaluate the performance of the M-AM system and compare it with the EUCAST broth microdilution reference method to determine the susceptibility of 77 A. fumigatus clinical strains to amphotericin B, itraconazole, voriconazole, and posaconazole. Overall, the essential agreements within ±2 dilutions were 100%, 62%, 58%, and 30% and the categorical agreements were 100%, 97%, 91%, and 87% for amphotericin B, itraconazole, voriconazole, and posaconazole, respectively. No categorical discrepancy was found for amphotericin B, but several categorical discordances were observed with azole antifungals. However, only 2 of the 16 azole-resistant strains confirmed by the cyp51A sequencing would have been misclassified by M-AM. The use of M-AM is probably suitable for the determination of the MICs of amphotericin B, but further evaluations are needed to confirm its usefulness for the determination of the MICs of azoles for A. fumigatus.
Relationship between People’s Interest in Medication Adherence, Health Literacy, and Self-Care: An Infodemiological Analysis in the Pre- and Post-COVID-19 Era
Authors: Grandieri Andrea , Trevisan Caterina , Gentili Susanna , Vetrano Davide Liborio , Liotta Giuseppe , Volpato Stefano
Published: July 2023

The prevalence of non-communicable diseases has risen sharply in recent years, particularly among older individuals who require complex drug regimens. Patients are increasingly required to manage their health through medication adherence and self-care, but about 50% of patients struggle to adhere to prescribed treatments. This study explored the relationship between interest in medication adherence, health literacy, and self-care and how it changed during the COVID-19 pandemic. We used Google Trends to measure relative search volumes (RSVs) for these three topics from 2012 to 2022. We found that interest in self-care increased the most over time, followed by health literacy and medication adherence. Direct correlations emerged between RSVs for medication adherence and health literacy (r = 0.674, p < 0.0001), medication adherence and self-care (r = 0.466, p < 0.0001), and health literacy and self-care (r = 0.545, p < 0.0001). After the COVID-19 pandemic outbreak, interest in self-care significantly increased, and Latin countries showed a greater interest in self-care than other geographical areas. This study suggests that people are increasingly interested in managing their health, especially in the context of the recent pandemic, and that infodemiology may provide interesting information about the attitudes of the population toward chronic disease management.
Sleep Disorders in Low-Risk Preterm Infants and Toddlers
Authors: Romeo Domenico , Arpaia Chiara , Lala Maria , Cordaro Giorgia , Gallini Francesca , Vento Giovanni , Mercuri Eugenio , Chiaretti Antonio
Published: July 2023

Sleep disorders are particularly important in the development of children, affecting the emotional, behavioural, and cognitive spheres. The incidence of these disorders has been assessed in different types of populations, including patients with a history of premature birth, who, from the literature data, would seem to have an increased incidence of sleep disorders at school age. The aims of the present study are: (i.) to assess the presence of sleep disorders in a population of very preterm infants at 6–36 months who are at low risk of neurological impairments using the Italian version of the Sleep Disturbance Scale for Children (SDSC) adapted for this age group, and (ii.) to identify possible differences from a control group of term-born infants. A total of 217 low-risk preterm and 129 typically developing infants and toddlers were included in the study. We found no differences in the SDSC total and the factor scores between these two populations of infants. Low-risk preterm infants and toddlers showed similar incidences of sleep disorders to their term-born peers. Further clinical assessments will be needed to confirm these data at school age.
Surgical Treatment of Corneal Shield Ulcer in Vernal Keratoconjunctivitis: A Systematic Review
Authors: Azizi Samim , Subhi Yousif , Rasmussen Marie Louise Roed
Published: July 2023

Background: Vernal keratoconjunctivitis (VKC) severely affects the quality of life of affected patients. The development of a shield ulcer is considered one of the most severe late-stage complications, which when untreated leads to irreversible vision loss. In this systematic review, we outlined the results of surgical treatments of corneal shield ulcers in VKC. Methods: We searched 12 literature databases on 3 April 2023 for studies of patients with VKC in which shield ulcers were treated by any surgical treatment. Treatment results were reviewed qualitatively. Assessments of the risk of bias of individual studies were made using the Clinical Appraisal Skills Programme. Results: Ten studies with 398 patients with VKC were eligible for the qualitative review. Two categories of surgical approaches were described: supratarsal corticosteroid injection and debridement with or without amniotic membrane transplantation. Almost all patients experienced resolution or improvement of their shield ulcers, regardless of treatment modality. Time to healing was faster with surgical debridement. A small proportion experienced recurrence and side effects. Conclusions: Surgical treatment for shield ulcers in VKC seems highly effective, but careful post-operative treatment and follow-ups are necessary due to the risk of recurrence and potential side effects.
Corporate Governance and Financial Statement Fraud during the COVID-19: Study of Companies under Special Monitoring in Indonesia
Authors: Arum Enggar Diah Puspa , Wijaya Rico , Wahyudi Ilham , Brilliant Aulia Beatrice
Published: July 2023

The COVID-19 pandemic had a wide-ranging impact, resulting in a global recession due to weakened purchasing power. This circumstance necessitates business organizations adapting to developments and being more conscious of the risk of financial statement fraud. The intention of this research is to investigate the way corporate governance affected financial statement fraud during the COVID-19 pandemic. To acquire empirical data for examining corporate governance variables on financial statement fraud, the research was examined using quantitative methods. The study takes advantage of secondary data acquired from annual reports of companies under special monitoring listed on the Indonesia Stock Exchange of 2020–2021. The logistic regression method was used to evaluate 134 data sets, and financial statement fraud was measured using the Z-Score and F-Score models. The results indicate that when using the Z-score, only the board size has a negative effect on financial statement fraud during the COVID-19 pandemic. Meanwhile, using the F-Score, the corporate governance variables studied are not proven to have an influence on financial statement fraud during the COVID-19 pandemic.
The Precarious Survival of an Ancient Cultural Landscape: The Thousand-Year-Old Olive Trees of the Valencian Maestrat (Spain)
Authors: Membrado-Tena Joan Carles , Hermosilla-Pla Jorge
Published: July 2023

The object of study of this article is the Valencian Maestrat olive growing system (eastern Spain). Its landscape and heritage values are evaluated through a qualitative assessment method based on a Spanish research project studying MTASs (Multifunctional, Territorialized Agrifood Systems), which can be described as an alternative agricultural model to the worldwide agro-industrial model. The results of this analysis show that this olive growing system coincides with the MTAS criteria as regards the landscape, which offers ecosystem services (food, structured soil, and absorption of CO2 emissions) and possesses cultural and heritage values (ancient olive trees, traditional rain-fed lands, unaltered plot structures, and dry stone structures). However, as far as production is concerned, the Maestrat olive growing system does not respond fully to MTAS principles: its particular environmental conditions (soil and climate) restrict the production of quality oil, which is processed and marketed mainly through cooperatives and is economically viable only thanks to CAP (Common Agricultural Policy) aid. Nevertheless, the cooperative system allows for the survival, albeit precarious, of this agricultural system. Only a small number of Maestrat olive growing farmers produce quality oil in accordance with MTAS criteria (such as local single varieties, unique flavour, proximity sales, territory closeness, or good farming practices).
Comparing Stakeholders’ Economic Values for the Institution of Payments for Ecosystem Services in Protected Areas
Authors: Kim Namhee , Kim Miju , Lee Sangkwon , Oh Chi-Ok
Published: July 2023

In order to maintain the provision of high-quality ecosystem services in wetlands, it is important to protect the ecosystems through the designation of protected areas. However, the process of designating protected areas can potentially give rise to social conflicts or problems by the acquisition of private lands. As an alternative, the institution of payments for ecosystem services (PES) can be a more viable solution. This study intends to propose reasonable contract standards for PES that consider the preferences of both beneficiaries and providers, which are necessary for the successful introduction of PES in wetland protection areas in Korea. In doing so, we employed choice experiments to estimate the willingness to pay (WTP) and willingness to accept (WTA) of different stakeholders. Our findings indicate that both beneficiaries and providers had a positive perception of PES contract terms. Moreover, the WTP and WTA values were comparable, suggesting that the unit price of PES could be determined within a reasonable range. These results can serve as a foundation for acquiring additional funds required for the introduction of PES in wetland protected areas.
Year-Round Bat Activity and Species Richness Near Temporary Ponds in the Mediterranean Region
Authors: Salvarina Ioanna , Georgiakakis Panagiotis , Kafkaletou Diez Artemis , Perivolioti Triantafyllia-Maria , Vassilaki Ioanna , Kalcounis-Rueppell Matina
Published: July 2023

Mediterranean temporary ponds are recognized as conservation priority habitats that face anthropogenic threats and are important habitats for a number of aquatic and terrestrial animals and plants. Bats are a diverse group of animals that use ponds for drinking and feeding on emerging aquatic insects and terrestrial insects in the riparian zone. We investigated the importance of temporary ponds for bats in Greece by acoustically sampling bat community structures and activity at temporary ponds throughout the year. We sampled monthly, from 3 to 13 months in 2019–2020, at sites at the pond edge and approximately 150–300 m away from the edge, at four temporary ponds in northern and southern Greece. Our results confirm the importance of temporary ponds for bats as activity was recorded year-round and was high in all but the winter months. In general, the distance to the edge of the pond and the presence of water in the pond explained bat activity together with air temperature. Importantly, whether dry or not, all ponds supported bat activity, independent of their particular characteristics. This study highlights the urgent need for the conservation of temporary ponds, especially in areas with limited water availability.
Potential of Personalized Dendritic Cell-Based Immunohybridoma Vaccines to Treat Prostate Cancer
Authors: Hawlina Simon , Zorec Robert , Chowdhury Helena H.
Published: July 2023

Prostate cancer (PCa) is the most commonly diagnosed cancer and the second most common cause of death due to cancer. About 30% of patients with PCa who have been castrated develop a castration-resistant form of the disease (CRPC), which is incurable. In the last decade, new treatments that control the disease have emerged, slowing progression and spread and prolonging survival while maintaining the quality of life. These include immunotherapies; however, we do not yet know the optimal combination and sequence of these therapies with the standard ones. All therapies are not always suitable for every patient due to co-morbidities or adverse effects of therapies or both, so there is an urgent need for further work on new therapeutic options. Advances in cancer immunotherapy with an immune checkpoint inhibition mechanism (e.g., ipilimumab, an anti-CTLA-4 inhibitor) have not shown a survival benefit in patients with CRPC. Other immunological approaches have also not given clear results, which has indirectly prevented breakthrough for this type of therapeutic strategy into clinical use. Currently, the only approved form of immunotherapy for patients with CRPC is a cell-based medicine, but it is only available to patients in some parts of the world. Based on what was gained from recently completed clinical research on immunotherapy with dendritic cell-based immunohybridomas, the aHyC dendritic cell vaccine for patients with CRPC, we highlight the current status and possible alternatives that should be considered in the future.
Investigation of the Hardness Development of Molybdenum Coatings under Thermal and Tribological Loading
Authors: Behrens Bernd-Arno , Stockburger Eugen , Wester Hendrik , Poll Gerhard , Pape Florian , Konopka Dennis , Heimes Norman
Published: July 2023

The increasing global demand for innovative and environmentally friendly lubricants can be met through the use of solid lubricants. By switching from conventional lubricants such as various oils or grease to solid lubricants, new scopes of application can also be opened up. The main requirements for solid lubricants are a reduction in the coefficient of friction (CoF) and an increase in wear resistance. Due to the favourable material properties, molybdenum (Mo) coatings fulfil the tribological requirements and are therefore promising solid lubricants which can be applied via physical vapour deposition (PVD). In this work, the impact of substrate temperature on the hot hardness of deposited Mo coatings was determined. The specimen with the highest hot hardness was then tribologically examined both at the micro and nano level. Through an analysis of the wear tracks by means of nanoindentation and scanning electron microscopy (SEM), it was possible to detect the influence of the tribological load separately from that of the thermal loads. The results showed that the tribological load influenced the Mo coating by significantly increasing its hardness. This was achieved due to the work hardening of the Mo layer leading to an increase in the wear resistance of the coating.
Fast Grasping Technique for Differentiated Mobile Phone Frame Based on Visual Guidance
Authors: Zhao Rongli , Bao Zeren , Xiao Wanyu , Zou Shangwen , Zou Guangxin , Xie Yuan , Leng Jiewu
Published: July 2023

With the increasing automation of mobile phone assembly, industrial robots are gradually being used in production lines for loading and unloading operations. At present, industrial robots are mainly used in online teaching mode, in which the robot’s movement and path are set by teaching in advance and then repeat the point-to-point operation. This mode of operation is less flexible and requires high professionalism in teaching and offline programming. When positioning and grasping different materials, the adjustment time is long, which affects the efficiency of production changeover. To solve the problem of poor adaptability of loading robots to differentiated products in mobile phone automatic assembly lines, it is necessary to quickly adjust the positioning and grasping of different models of mobile phone middle frames. Therefore, this paper proposes a highly adaptive grasping and positioning method for vision-guided right-angle robots.
Research into Dynamic Error Optimization Method of Impeller Blade Machining Based on Digital–Twin Technology
Authors: Li Rongyi , Wang Shanchao , Wang Chao , Wang Shanshan , Zhou Bo , Liu Xianli , Zhao Xudong
Published: July 2023

A TC4 impeller blade is a typical weak, rigid, thin–walled part. The contact area between a cutting tool and a workpiece has strong time–varying characteristics. This leads to a strong non–linear variation in cutting load. So, in this kind of part, the processing error is difficult to control. To solve this problem, a method of processing error prediction and intelligent controlling which considers the effect of tool wear time variation is proposed by combining digital–twinning technology. Firstly, an iterative model for digital–twin process optimization is constructed. Secondly, an iterative prediction model of the machining position following the milling force and considering the effect of tool wear is proposed. Based on these models, the machining error of the TC4 impeller blade under dynamic load is predicted. Dynamic machining error prediction and intelligent control are realized by combining the digital–twin model and the multi–objective process algorithm. Finally, the machining error optimization effect of the proposed digital–twin model is verified via a comparison experiment of impeller blade milling. In terms of the precision of milling force mapping, the average error after optimization is less than 8%. The maximum error is no more than 14%. In terms of the optimization effect, the average error of the optimized workpiece contour is reduced by about 20%. The peak contour error is reduced by approximately 35%.
Phasor-Like Interpretation of the Angular Velocity of the Wheels of Omnidirectional Mobile Robots
Authors: Palacín Jordi , Rubies Elena , Bitriá Ricard , Clotet Eduard
Published: July 2023

Omnidirectionality is a feature that allows motion in any direction without orientation maneuvers. Omnidirectional mobile robots are usually based on omni or mecanum wheels. The motion of an omnidirectional mobile robot is defined by a target motion command M=v,α,ω, where v is the module of the translational velocity; α is the angular orientation of the translational velocity, and ω is the angular velocity of the mobile robot. The motion is achieved by converting the target motion command into the target angular velocities that must be applied to the active wheels of the robot. This work proposes a simplified phasor-like interpretation of the relationship between the parameters of a specific motion command and the angular velocities of the wheels. The concept of phasor-like notation is validated from the analysis of the kinematics of omnidirectional mobile robots using omni wheels and mecanum wheels. This simplified phasor-like notation fosters unconstrained conceptual design of single-type and hybrid multi-wheeled omnidirectional mobile robots without the distribution or type of wheels being a design constraint.
Study on Fatigue Characteristics of Rivets in Bearing Cage for an Aeroengine Transmission System
Authors: Cui Yongcun , Cai Linshen , Zhang Song , Cui Yufei , Deng Sier
Published: July 2023

This study focuses on the rivet early fatigue characteristics in a deep-groove ball bearing cage for a transmission system in a turboprop engine. Nonlinear dynamic differential equations for the deep-groove ball bearing with a two-piece cage were developed. The rivet stress was used to identify the early failure mechanism of the rivets. This investigation revealed that by delivering an optimal preload of the rivet causes the two halves of the cage have less misalignment and a lower rivet stress. The fit relationship between the rivet and the rivet bore has a significant influence on the rivet stress. Excessive clearance increases the stress on the head of the rivet, while excessive interference increases the stress on the middle of the rivet. For the 1.5 mm diameter rivet analyzed in this study, the appropriate fit relationship is −0.02 mm–0 mm. A reasonable matching value of the load and the speed and the cage clearance ratio are beneficial to reducing the rivet stress. The impact load acting on the bearing and a ring misalignment can increase the rivet stress.
Existence of Positive Ground State Solutions for Fractional Choquard Systems in Subcritical and Critical Cases
Authors: Lu Huiqin , Ouyang Kexin
Published: July 2023

We investigate a class of fractional linearly coupled Choquard systems. For the subcritical case and all critical cases, we prove the existence, nonexistence and symmetry of positive ground state solutions of systems, by using the Nehari manifold method, the Pohožaev identity and the Schwartz symmetrization rearrangements. In particular, we overcome the lack of compactness of the critical nonlinearities by using the behaviour of sufficiently small Nehari energy levels.
Algebraic-Connectivity-Based Multi-USV Distributed Formation Method via Adding a Reverse Edge
Authors: Wang Jingchen , Shan Qihe , Zhu Jun , Cheng Xiaofeng , Wei Baoze
Published: July 2023

This paper concerns the formation problem in multi-USV cluster formation containment tracking tasks with a special topology. A topology reconstruction method was proposed that enables the followers’ formation to be dispersed while achieving the fastest convergence rate for the system. This topology structure is based on tree topology and DAG (directed acyclic graph) local structure stem as prototypes, using the principle of adding reverse edges on the stem to reduce algebraic connectivity. By adding a reverse edge to obtain a more dispersed formation, a method for selecting appropriate reverse edges was achieved. Through relevant theoretical quantitative and qualitative analysis, it was demonstrated that adding this reverse edge can enable the system to achieve the fastest convergence rate. Finally, through simulation experiments, it was verified that the selected reverse edge can optimize the formation of followers and achieve the fastest convergence rate.
Artificial Intelligence in Business-to-Customer Fashion Retail: A Literature Review
Authors: Goti Aitor , Querejeta-Lomas Leire , Almeida Aitor , de la Puerta José Gaviria , López-de-Ipiña Diego
Published: July 2023

Many industries, including healthcare, banking, the auto industry, education, and retail, have already undergone significant changes because of artificial intelligence (AI). Business-to-Customer (B2C) e-commerce has considerably increased the use of AI in recent years. The purpose of this research is to examine the significance and impact of AI in the realm of fashion e-commerce. To that end, a systematic review of the literature is carried out, in which data from the Web Of Science and Scopus databases were used to analyze 219 publications on the subject. The articles were first categorized using AI techniques. In the realm of fashion e-commerce, they were divided into two categories. These categorizations allowed for the identification of research gaps in the use of AI. These gaps offer potential and possibilities for further research.
A Supply Chain Model with Carbon Emissions and Preservation Technology for Deteriorating Items under Trade Credit Policy and Learning in Fuzzy
Authors: Alamri Osama Abdulaziz
Published: July 2023

In this study, a supply chain model is proposed with preservation technology under learning fuzzy theory for deteriorating items where the demand rate depends on the selling price and also treats as a triangular fuzzy number. The deterioration rate of any item cannot be eliminated due to its natural process, but it can be controlled with the help of preservation technology. Some harmful gases are emitted during the preservation process due to deteriorating items that harm the environment. In general, it can be easily seen that most of the sellers offer a trade credit policy to their regular buyers. In this paper, the retailer’s inventory stock reduces due to demand and deterioration. It is also assumed that some units are defective due to machine defects or delivery inefficiency. The retailer accepted the policy of trade credit offered by the seller. The aim of this paper is to enhance the profit of the supply chain partners. We proposed a theorem to get the optimal values of the selling price and cycle length. The retailer’s total profit is a function of selling price and cycle length, and the retailer’s total profit is optimized with respect to selling price and cycle length under trade-credit. Numerical examples are also presented for the validation of the present study, and sensitivity analysis is also discussed to know the robustness of the supply chain model. Managerial insight and observation have been given in the sensitivity section. Limitations and future work of this paper have been presented in the conclusion section.
Leveraging Searchable Encryption through Homomorphic Encryption: A Comprehensive Analysis
Authors: Amorim Ivone , Costa Ivan
Published: July 2023

The widespread adoption of cloud infrastructures has revolutionized data storage and access. However, it has also raised concerns regarding the privacy of sensitive data. To address these concerns, encryption techniques have been widely used. However, traditional encryption schemes limit the efficient search and retrieval of encrypted data. To tackle this challenge, innovative approaches have emerged, such as the utilization of Homomorphic Encryption (HE) in Searchable Encryption (SE) schemes. This paper provides a comprehensive analysis of the advancements in HE-based privacy-preserving techniques, focusing on their application in SE. The main contributions of this work include the identification and classification of existing SE schemes that utilize HE, a comprehensive analysis of the types of HE used in SE, an examination of how HE shapes the search process structure and enables additional functionalities, and the identification of promising directions for future research in HE-based SE. The findings reveal the increasing usage of HE in SE schemes, particularly Partially Homomorphic Encryption. The popularity of this type of HE schemes, especially Paillier’s cryptosystem, can be attributed to its simplicity, proven security properties, and widespread availability in open-source libraries. The analysis also highlights the prevalence of index-based SE schemes using HE, the support for ranked search and multi-keyword queries, and the need for further exploration in functionalities such as verifiability and the ability to authorize and revoke users. Future research directions include exploring the usage of other encryption schemes alongside HE, addressing omissions in functionalities like fuzzy keyword search, and leveraging recent advancements in Fully Homomorphic Encryption schemes.
Carbonized Nickel Complex of Sodium Pectate as Catalyst for Proton-Exchange Membrane Fuel Cells
Authors: Kholin Kirill V. , Sabirova Aigul F. , Kadirov Danis M. , Khamatgalimov Ayrat R. , Khrizanforov Mikhail N. , Nizameev Irek R. , Morozov Mikhail V. , Gainullin Radis R. , Sultanov Timur P. , Minzanova Salima T. , Nefed’ev Eugene S. , Kadirov Marsil K.
Published: July 2023

Sodium pectate derivatives with 25% replacement of sodium ions with nickel ions were obtained by carbonization to temperatures of 280, 550, and 800 °C, under special protocols in an inert atmosphere by carbonization to temperatures of 280, 550, and 800 °C. The 25% substitution is the upper limit of substitution of sodium for nickel ions, above which the complexes are no longer soluble in water. It was established that the sample carburized to 550 °C is the most effective active element in the hydrogen-oxidation reaction, while the sample carbonized up to 800 °C was the most effective in the oxygen-reduction reaction. The poor performance of the catalytic system involving the pectin coordination biopolymer carbonized up to 280 °C was due to loss of proton conductivity caused by water removal and mainly by two-electron transfer in one catalytic cycle of the oxygen-reduction reaction. The improved performance of the system with coordination biopolymer carbonized up to 550 °C was due to the better access of gases to the catalytic sites and four-electron transfer in one catalytic cycle. The (Ni-NaPG)800C sample contains metallic nickel nanoparticles and loose carbon, which enhances the electrical conductivity and gas capacity of the catalytic system. In addition, almost four-electron transfer is observed in one catalytic cycle of the oxygen-reduction reaction.
Tunable Complex Permittivity and Strong Microwave Absorption Properties of Novel Dielectric-Conductive ZnO/C Hybrid Composite Absorbents
Authors: Yan Junxiao , Jia Hongyao , Zhou Liang , Wang Zhenjun , Wang Hongbo
Published: July 2023

Modern electronic information technology has led social life into inevitable electromagnetic pollution, making microwave absorbing materials more and more important. Herein, dielectric-conductive ZnO/C hybrid composite absorbents were prepared by two-step carbonization with ZnO powders and glucose as critical materials. The electrical conductivity, complex permittivity, and reflection loss were analyzed to study the dielectric and microwave absorption properties. Results show that the prepared ZnO/C composite absorbents exist in the form of rod-like ZnO dispersed in the irregular block carbon, and the complex permittivity of the composite absorbents can be adjusted via varying the carbonization temperature. The minimum reflection loss of −25.64 dB is achieved at 1.8 mm thickness for the composite absorbent with 50 wt.% absorbent content as the final carbonization temperature is 750 °C, and the optimum effective absorption bandwidth is 2.21 GHz at 9.64–11.85 GHz. The excellent microwave absorption properties of ZnO/C composite absorbents are attributed to the combination actions of dipole polarization, conductance loss, and interface polarization, which is significant for the purposeful design of superior microwave-absorbing materials with dielectric and conductive absorbents.
Numerical Investigation of Fluid Flow and Heat Transfer in High-Temperature Wavy Microchannels with Different Shaped Fins Cooled by Liquid Metal
Authors: Yu Tingfang , Guo Xing , Tang Yicun , Zhang Xuan , Wang Lizhi , Wu Tao
Published: July 2023

The microchannel heat sink has been recognized as an excellent solution in high-density heat flux devices for its high efficiency in heat removal with limited spaces; however, the most effective structure of microchannels for heat dissipation is still unknown. In this study, the fluid flow and heat transfer in high-temperature wavy microchannels with various shaped fins, including the bare wavy channel, and the wavy channel with circular, square, and diamond-shaped fins, are numerically investigated. The liquid metal-cooled characteristics of the proposed microchannels are compared with that of the smooth straight channel, with respect to the pressure drop, average Nusselt number, and overall performance factor. The results indicate that the wavy structure and fin shape have a significant effect on the heat sink performance. Heat transfer augmentation is observed in the wavy channels, especially coupled with different shaped fins; however, a large penalty of pressure drops is also found in these channels. The diamond-shaped fins yield the best heat transfer augmentation but the worst pumping performance, followed by the square-, and circular-shaped fins. When the Re number increases from 117 to 410, the Nu number increases by 61.7% for the diamond fins, while the ∆p increases as much as 7.5 times.
Petrogenesis of Syn-Collisional Adakitic Granitoids and Their Copper Mineralization Potential in the North Qilian Suture Zone
Authors: Chen Yuxiao , Zhang Tianqi , Cui Ying , Song Shuguang
Published: July 2023

The petrogenesis of late Ordovician–early Silurian adakitic plutons in the North Qilian suture zone (NQSZ) and their copper mineralization potential remain poorly understood. Here we present a detailed study of the Heishishan (HSS) granodiorite–granite pluton, spatially associated with Cu–Au mineralization in the eastern section of the NQSZ. Zircon U–Pb dating confirms that the granodiorite–granite were formed at ca. 438–435 Ma, in association with a continental collision. Geochemically, the granitoids resemble low-Mg adakitic rocks featured by elevated Sr/Y and (La/Yb)N ratios with depleted MgO, Cr, and Ni concentrations, suggesting minimal mantle contribution. They are sodium rich with K2O/Na2O < 1, and have higher and more varied Sr/Y, but lower La/Yb than those from the continental lower crust. The εHf(t) values of zircon grains are positive and vary in a wide range of +2.0–12.7, indicating a heterogeneous source rather than a single arc basaltic source. They show moderately radiogenic Sr and Nd isotope compositions with initial 87Sr/86Sr ratios of 0.705101–0.706312 and εNd(t) values of +0.5–1.0, most likely a mixed source of the oceanic basaltic crust plus ca. 15–20% overlying sediments. The magmatic oxygen fugacity was relatively low as indicated by zircon Ce(IV)/Ce(III) ratios of 32–156, which is unfavorable for a large copper mineralization.
Characteristics and Formation Stages of Natural Fractures in the Fengcheng Formation of the Mahu Sag, China: Insights from Stable Carbon and Oxygen Isotope and Fluid Inclusion Analysis
Authors: Wang Wei , Xie Xinhui , Liu Caiguang , Cao Feng , Zheng Guoqing , Wang Zhenlin , Chen Gang , Deng Hucheng , He Jianhua , Li Kesai
Published: July 2023

The Fengcheng Formation of the Mahu Sag is an unconventional reservoir that is of paramount importance for exploration and development of hydrocarbon resource. However, current research on natural fractures in the Fengcheng Formation remains limited, posing challenges for exploration of hydrocarbon resource in the region. This study is based on core observations, thin section identification, geochemical testing and the evolution of regional tectonic movements to investigate the characteristics and periods of formation of natural fractures to address this gap. According to the characteristics of natural fractures in the drilling core samples and microsections, the natural fractures in the Fengcheng Formation can be grouped into structural fractures and atectonic fractures. Structural fractures can be further divided into three subtypes: high-angle interlayer shear fractures, along-layer shear fractures, and tensile fractures. Additionally, non-tectonic fractures in this studied area are primarily bedding fractures, hydraulic fractures, and hydrocarbon-generating overpressure fractures. Vertically, fracture development is more prominent at the bottom of Feng #2 Formation and at the top of Feng #3 Formation. Results also indicate that natural fractures primarily formed during three distinct tectonic movement periods. The initial stage of fracture evolution pertains to the Late Permian period (243–266 Ma), filled with fibrous calcite, and exhibiting a uniform temperature of 70–100 °C. The second stage of fracture evolution occurred during the Late Indosinian to Early Yanshanian period (181–208 Ma), mostly filled or semi-filled with calcite, with a uniform temperature of 110–130 °C. The third stage of fracture development happened during the late Yanshanian to early Himalaya period (50–87 Ma), predominantly filled with calcite, and presenting a uniform temperature of 130–150 °C. Among the various types of structural fractures, the density of high-angle interlayer shear fractures demonstrates a positive correlation with daily gas production, indicating their vital role in promoting hydrocarbon resource production and transportation. Furthermore, microfractures generated by hydrocarbon-generating overpressure fractures exhibit small pore sizes and strong connectivity. These microfractures can create an effective permeability system by connecting previously isolated micropores in shale reservoirs, thus establishing interconnected pore spaces in the shale formation.