bluuebunny/crossref_metadata_2025 huggingface dataset:
Retrospective Study of the Prevalence and Associated Factors of Gallbladder Polyps among Residents of Two Korean Cities
Authors: Kwon Oh-Sung , Kim Young-Kyu , Kim Hyeon Ju
Published: April 2024

Background/Aims: Well-known risk factors for gallbladder polyps include metabolic syndrome, age, and dyslipidemia. Jeju Island is approximately 80 km from the Korean peninsula and is divided into two administrative regions (Jeju City and Seogwipo City), with Mount Halla intervening in the center. Jeju City has higher employment and birth rates than Seogwipo City. Age and alcohol consumption differ between the two regions, and these factors may affect the prevalence of gallbladder polyps (GBPs). Therefore, we investigated the prevalence of GBPs and compared various factors, including alcohol consumption habits and age, associated with GBPs among residents in the two regions. Methods: This study included 21,734 residents who visited the Health Screening and Promotion Center of Jeju National University Hospital between January 2009 and December 2019. We investigated the prevalence and associated factors of GBPs among residents of Jeju City and Seogwipo City. Results: The prevalence of GBPs in Jeju City and Seogwipo City was 9.8% and 8.9% (p = 0.043), respectively. The mean age and rate of high-risk alcohol intake were higher in Seogwipo City. The mean body mass index and levels of fasting blood glucose, total cholesterol, low-density lipoprotein cholesterol, aspartate aminotransferase, gamma-glutamyl transferase, and alkaline phosphatase were lower in Jeju City. Conclusions: This study demonstrated a significant difference in GBP prevalence between the two regions of Jeju Island. Age and alcohol consumption might contribute to this difference; however, further prospective cohort studies are warranted to confirm our findings.
The Use of Thrombectomy during Primary Percutaneous Coronary Intervention: Resurrecting an Old Concept in Contemporary Practice
Authors: Satti Zahir , Omari Muntaser , Bawamia Bilal , Cartlidge Timothy , Egred Mohaned , Farag Mohamed , Alkhalil Mohammad
Published: April 2024

Optimal myocardial reperfusion during primary percutaneous coronary intervention (pPCI) is increasingly recognized to be beyond restoring epicardial coronary flow. Both invasive and non-invasive tools have highlighted the limitation of using this metric, and more efforts are focused towards achieving optimal reperfusion at the level of the microcirculation. Recent data highlighted the close relationship between thrombus burden and impaired microcirculation in patients presenting with ST-segment elevation myocardial infarction (STEMI). Moreover, distal embolization was an independent predictor of mortality in patients with STEMI. Likewise, the development of no-reflow phenomenon has been directly linked with worse clinical outcomes. Adjunctive thrombus aspiration during pPCI is intuitively intended to remove atherothrombotic material to mitigate the risk of distal embolization and the no-reflow phenomenon (NRP). However, prior trials on the use of thrombectomy during pPCI did not support its routine use, with comparable clinical endpoints to patients who underwent PCI alone. This article aims to review the existing literature highlighting the limitation on the use of thrombectomy and provide future insights into trials investigating the role of thrombectomy in contemporary pPCI.
The Morphology of Nasal Polyps in Different Age Groups: Histopathological Features
Authors: Fiorentino Vincenzo , Martini Maurizio , Galletti Cosimo , Pizzimenti Cristina , Franchina Mariausilia , Ieni Antonio , Fadda Guido , Galletti Bruno , Tuccari Giovanni
Published: April 2024

Background: Nasal polyps (NPs) represent the end-stage manifestation of chronic rhinosinusitis (CRS), a relatively common pathological condition encountered in all ages of life. Methodology: The aim of our study was to evaluate the histological features and inflammatory cellular components of NPs in a retrospective cohort (143 cases) of pediatric, adult and elderly populations in order to discuss the possible morphological age-related differences statistically documented. Results: In the pediatric group, the inflammatory infiltrate presented many eosinophils mixed with lymphocytes, while in the adult population, lymphocytes and plasma cells were mainly evident, frequently with a perivascular distribution or with the formation of subepithelial lymphoid nodules. In the elderly population, inflammation was less evident and was associated with cavernous-like angecthatic structures with thrombotic stratification. Nearly all morphological findings exhibited statistically significant values among differently aged subgroups. Conclusions: Our results support the presence of histological specificities of NPs at different ages of life, providing new insight into the etiopathogenesis of NPs. The future role of biological therapies, mainly in cases refractory to already available standard medical and surgical treatments, may be analyzed by a prospective study using a larger cohort with a long-term evaluation also in relation to a possible relapse.
Clinical Application of Different Liquid Biopsy Components in Hepatocellular Carcinoma
Authors: Xu Jing , Zhao Yuanyuan , Chen Zhishui , Wei Lai
Published: April 2024

Hepatocellular carcinoma (HCC) is the most common form of primary liver cancer, usually occurring in the background of chronic liver disease. HCC lethality rate is in the third highest place in the world. Patients with HCC have concealed early symptoms and possess a high-level of heterogeneity. Once diagnosed, most of the tumors are in advanced stages and have a poor prognosis. The sensitivity and specificity of existing detection modalities and protocols are suboptimal. HCC calls for more sophisticated and individualized therapeutic regimens. Liquid biopsy is non-invasive, repeatable, unaffected by location, and can be monitored dynamically. It has emerged as a useable aid in achieving precision malignant tumor treatment. Circulating tumor cells (CTCs), circulating nucleic acids, exosomes and tumor-educated platelets are the commonest components of a liquid biopsy. It possesses the theoretical ability to conquer the high heterogeneity and the difficulty of early detection for HCC patients. In this review, we summarize the common enrichment techniques and the clinical applications in HCC for different liquid biopsy components. Tumor recurrence after HCC-related liver transplantation is more insidious and difficult to treat. The clinical use of liquid biopsy in HCC-related liver transplantation is also summarized in this review.
Valuation of Patent-Based Collaborative Synergies under Strategic Settings with Multiple Uncertainties: Rainbow Real Options Approach
Authors: Čirjevskis Andrejs
Published: April 2024

Recent years have seen increasing initiatives involving more applications of real options to value the strategizing process. These initiatives, referred to as Real Option Theory (ROT), imply greater inclusiveness of simple and advanced real options in strategizing processes. While substantial theoretical groundwork on ROT has been laid in corporate finance, and both qualitative and quantitative studies on ROT in business management journals are appearing on an increasing basis, there remain significant opportunities for more research on strategic synergism in patent-based acquisitions. In this vein, the current paper aims to explore a rainbow real options application (real options that are exposed to two sources of uncertainty) to measure patent-based collaborative synergies in high-tech mergers and acquisitions. Having conducted the deviant case study of ZOOX start-up’s acquisition by Amazon.com in 2020, this paper justifies the proposition of the employability of rainbow real options for the valuation of network and relational synergies in highly risky patent-based acquisitions with multiple uncertainties.
Level-Crossing Characteristics of an Actively Managed Buffer
Authors: Chydzinski Andrzej
Published: April 2024

In this paper, we examine a buffer with active management that rejects packets basing on the buffer occupancy. Specifically, we derive several metrics characterizing how effectively the algorithm can prevent the queue of packets from becoming too long and how well it assists in flushing the buffer quickly when necessary. First, we compute the probability that the size of the queue is kept below a predefined level L. Second, we calculate the distribution of the amount of time needed to cross level L, the buffer overflow probability, and the average time to buffer overflow. Third, we derive the distribution of the amount of time required to flush the buffer and its average value. A general modeling framework is used in derivations, with a general service time distribution, general rejection function, and a powerful model of the arrival process. The obtained formulas enable, among other things, the solving of many design problems, e.g., those connected with the design of wireless sensor nodes using the N-policy. Several numerical results are provided, including examples of design problems and other calculations.
Relationships between Resident Activities and Physical Space in Shrinking Cities in China—The Case of Chaoyang City
Authors: Yang Wenshi , Chen Fan , Wei Qianqian , Peng Zhenwei
Published: April 2024

Shrinking cities suffer from a decreased level of resident activities. As a result, areas with low levels of resident activities may become breeding grounds for social issues. To ease and prevent social issues, it is important to deploy physical space optimisation strategies to effectively guide the distribution of resident activities in shrinking cities. To support the development of such spatial strategies, this paper introduces machine learning-based methods for analysing the nuanced non-linear relationship between resident activities and physical space in shrinking cities. Utilising dual-scale grids, this study calculates multi-source spatial elements, which are subsequently integrated with resident activity data to construct a gradient boosting decision tree model. It then analyses the weight of different spatial elements’ impacts on resident activities and their nonlinear relationships. The model proposed in this study demonstrates good precision in construing the relationship between resident activities and physical space. Based on the research findings, strategies for different types of spatial development in shrinking cities are drawn out. This paper advocates for the application of this analytical approach before conducting spatial planning in shrinking cities to maximise the effectiveness of spatial development in guiding resident activities.
Comparison of the Economic and Environmental Sustainability for Different Peatland Strategies
Authors: Balode Lauma , Blumberga Dagnija
Published: April 2024

Previous studies of the literature show that there are great uncertainties regarding costs and gains for peatland restoration strategies and that the monetary estimation of peatland restoration and possible alternatives can be complicated. The research aims to compare the economic costs and benefits of existing peatland restoration strategies and alternative use of peat and peatlands. A core method for the evaluation of the economic aspects of each strategy used is the composite index method. Information for constructing the composite index is based on data from the scientific literature, reports, and local project studies. In the study, peatland strategies, peat extraction, and alternative use in products were mutually compared with existing strategies. The highest composite index among strategies was for the production of insulation boards and cultivation of paludicultures using cattail or sphagnum farming. Cultivation of paludicultures can be an economically viable strategy if costs and gains are evaluated. Cultivation of cattail or sphagnum can make economic gains for landowners and farmers, and solutions for the reduction in necessary initial investments should be sought. Harvested biomass can be used for high-added-value products, in this case, insulation boards from cattail (Typha). Therefore, peat biomass can be used as an economically valuable resource, and raw material for insulation board production is obtained without the extraction of peat. Also, ecosystem services and potential income are not reduced.
Multi-Scenario Simulation and Eco-Environmental Effects Analysis of Land Use/Cover Change in China by an Integrated Cellular Automata and Markov Model
Authors: Wang Huihui , Xue Hanyu , Yang Yunsong , He Wanlin , Liu Suru , Zhong Yuhao , Gao Xiaoyong , Xu Tingting
Published: April 2024

Land use transitions play a critical role in ecological environmental restoration, but they are also plagued by ecological environmental problems caused by excessive land resource development. In this study, we propose a methodological framework for unveiling the nexus profile of land use/cover change (LUCC) and eco-environmental effects. This study explored the spatiotemporal evolution patterns of LUCC over a long time series based on high-precision land use data from 1990 to 2020. Then, the ecological values (EVs) of various cities were calculated to obtain the ecological contribution rate of different land use types in the process of change. Finally, the future development trends of land use and ecological environmental quality were predicted under multiple scenarios using the cellular automata–Markov model, and scientific policy recommendations were proposed. The results showed that the expansion trajectory of the construction land in the urban agglomeration mainly expanded inwards along the mouth of the Pearl River, and the conversion of cultivated land to construction land was the most significant type of land use change. The overall ecological environmental quality of the study area showed a downwards trend, with Shenzhen exhibiting the largest decrease in EVs. Cultivated land contributed significantly to improving regional ecological environmental quality, while the land use transition types with relatively large contributions to environmental quality deterioration were conversions to construction land. Under the scenario of coordinated protection, the degree of cultivated land area reduction was significantly reduced, and the area of forestland showed a positive growth trend, with the expansion trend of construction land being reversed. These research findings can enrich the theoretical research on the sustainable development of urban agglomerations and provide reliable data support for policy-making.
Variant Choices of Future Time Reference in Galician: The Grammaticalization of [haber (de) + infinitive] as a Window to Diachronic Change
Authors: Brown Esther L. , Rivas Javier
Published: April 2024

Compared to neighboring Romance languages, Galician currently maintains a more ubiquitous usage of the construction [haber (present) + (de) + infinitive] as a future marker in variation with the periphrastic construction with ir ‘go’ and the morphological future. We examine this under-studied construction to gain a better understanding of Galician grammar and also contribute new data with which to consider diachronic change regarding the grammaticalization of the future from obligation markers. We conduct a variationist analysis of 1589 tokens of future forms in recorded conversations (CORILGA) in order to determine the frequency of usage, patterns of variation, linguistic conditioning and degree of grammaticalization of the periphrastic forms with haber and ir in contrast to the morphological variant. We find evidence to suggest that the periphrastic construction with haber is highly grammaticalized as a future marker and we identify factors of the production context that modulate the grammaticalization process.
Bilingual Texting in the Age of Emoji: Spanish–English Code-Switching in SMS
Authors: Montes-Alcalá Cecilia
Published: April 2024

Technology and computer-mediated communication (CMC) have quickly transformed the means of interaction among monolingual and bilingual individuals alike, especially in the younger generations. While e-mail once replaced traditional “snail mail”, today’s youth networks mainly via social media and short message services (SMS). Digital communication has thus become a fertile ground for sociolinguistic research. The present study aims to contribute to the field of “electronic” code-switching, specifically in the emerging area of text messaging. To this end, I analyze The Bilingual Youth Texts Corpus, a collection of text messages among urban emergent Spanish–English bilinguals in New York City. The main findings indicate that (1) although it is not the most common practice, participants do engage in code-switching when texting each other; (2) their language mixing obeys most of the socio-pragmatic and communicative patterns attested in oral production (such as emphasis, elaboration, lexical need and, especially, tag switches) along with other functions (textisms) which are idiosyncratic to CMC; and (3) the language choices made by these bilinguals reveal a linguistic and a cultural belonging to two worlds where they may and must use both languages to fully express themselves online just like in real life.
New Equations for the Estimation of the Age of the Formation of the Harris Lines
Authors: Kulus Michał J. , Cebulski Kamil , Kmiecik Piotr , Sputa-Grzegrzółka Patrycja , Grzelak Joanna , Dąbrowski Paweł
Published: April 2024

Harris Lines (HLs) are transverse, sclerotic lines that can be visualized by X-ray imaging and that occur in long bones, most commonly in the tibia and femur. HLs are associated with disrupted bone mineralization during endochondral ossification, affecting the normal growth process. The etiology of HLs is debated, with some claims linking their presence to detrimental factors such as inflammation, malnutrition, alcohol abuse, and diseases. The age at which HLs form can be estimated based on their location, which allows for a retrospective assessment of the individual’s health status during childhood or youth. The current study is concerned with providing new equations to estimate the age of Harris Line occurrences using a simple calculating tool. Bone growth curves were derived based on a dataset provided by Byers in 1991 using non-linear estimation. The best model was chosen with the Akaike Information Criterion. New and old methods were compared through Bland–Altman plots. As a result, we managed to produce reliable, well-fitted growth curves, concordant with previous methods.
Machine Learning Reveals Impacts of Smoking on Gene Profiles of Different Cell Types in Lung
Authors: Ma Qinglan , Shen Yulong , Guo Wei , Feng Kaiyan , Huang Tao , Cai Yudong
Published: April 2024

Smoking significantly elevates the risk of lung diseases such as chronic obstructive pulmonary disease (COPD) and lung cancer. This risk is attributed to the harmful chemicals in tobacco smoke that damage lung tissue and impair lung function. Current research on the impact of smoking on gene expression in specific lung cells is limited. This study addresses this gap by analyzing gene expression profiles at the single-cell level from 43,539 lung endothelial cells, 234,349 lung epithelial cells, 189,843 lung immune cells, and 16,031 lung stromal cells using advanced machine learning techniques. The data, categorized by different lung cell types, were classified into three smoking states: active smoker, former smoker, and never smoker. Each cell sample encompassed 28,024 feature genes. Employing an incremental feature selection method within a computational framework, several specific genes have been identified as potential markers of smoking status in different lung cell types. These include B2M, EEF1A1, and TPT1 in lung endothelial cells; FTL and MT-ATP8 in lung epithelial cells; HLA-B and HLA-C in lung immune cells; and HSP90B1 and LCN2 in lung stroma cells. Additionally, this study developed quantitative rules for representing the gene expression patterns related to smoking. This research highlights the potential of machine learning in oncology, enhancing our molecular understanding of smoking’s harm and laying the groundwork for future mechanism-based studies.
Unveiling Gene Expression Dynamics during Early Embryogenesis in Cynoglossus semilaevis: A Transcriptomic Perspective
Authors: Cheng Xinyi , Jiang Wei , Wang Qian , Liu Kaiqiang , Dai Wei , Liu Yuyan , Shao Changwei , Li Qiye
Published: April 2024

Commencing with sperm–egg fusion, the early stages of metazoan development include the cleavage and formation of blastula and gastrula. These early embryonic events play a crucial role in ontogeny and are accompanied by a dramatic remodeling of the gene network, particularly encompassing the maternal-to-zygotic transition. Nonetheless, the gene expression dynamics governing early embryogenesis remain unclear in most metazoan lineages. We conducted transcriptomic profiling on two types of gametes (oocytes and sperms) and early embryos (ranging from the four-cell to the gastrula stage) of an economically valuable flatfish–the Chinese tongue sole Cynoglossus semilaevis (Pleuronectiformes: Cynoglossidae). Comparative transcriptome analysis revealed that large-scale zygotic genome activation (ZGA) occurs in the blastula stage, aligning with previous findings in zebrafish. Through the comparison of the most abundant transcripts identified in each sample and the functional analysis of co-expression modules, we unveiled distinct functional enrichments across different gametes/developmental stages: actin- and immune-related functions in sperms; mitosis, transcription inhibition, and mitochondrial function in oocytes and in pre-ZGA embryos (four- to 1000-cell stage); and organ development in post-ZGA embryos (blastula and gastrula). These results provide insights into the intricate transcriptional regulation of early embryonic development in Cynoglossidae fish and expand our knowledge of developmental constraints in vertebrates.
Further Insights on Honey and Propolis from Gerês (Portugal) and Their Bioactivities: Unraveling the Impact of Beehive Relocation
Authors: Freitas Ana Sofia , Oliveira Rui , Almeida-Aguiar Cristina
Published: April 2024

Propolis, a bee product, is known for its variability of chemical and bioactive profiles. However, Portuguese propolis from Gerês, normally obtained by mixing propolis from three places—Bugalho, Felgueiras and Toutelo—has shown similar chemical and biological profiles over the years. Recently, a new propolis place—Roca—was added to the apiary to replace Bugalho, lost to the 2017 wildfires, hence questioning the previously claimed constancy of Gerês propolis. To unravel to what extent the beehive relocation affected this constancy, we studied different Gerês propolis samples collected in three consecutive years (2017–2019) composed of different combinations of source places. Two honey samples, collected before (2017) and after (2018) the occurrence of the wildfire, were also investigated. Total phenolics, flavonoids and ortho-diphenols contents were determined and the antioxidant and antimicrobial activities were evaluated, using the DPPH assay and the agar dilution method, respectively. Although both antimicrobial and antioxidant activities were generally in the ranges usually obtained from Gerês propolis, some variations were detected for the samples, with different compositions when compared to previous years. This work reinforces the importance of the consistency of a combination of several factors for the protection and preservation of the flora near the hives, providing bee products with more constant chemical and biological profiles over the years.
Aroplectrus dimerus (Hymenoptera: Eulophidae), Ectoparasitoid of the Nettle Caterpillar, Oxyplax pallivitta (Lepidoptera: Limacodidae): Evaluation in the Hawaiian Islands
Authors: Yalemar Juliana A. , Nagamine Walter T. , Bautista Renato C. , Cho Dexter Y. , Nakahara Larry M. , Ramadan Mohsen M.
Published: April 2024

The stinging nettle caterpillar, Oxyplax (syn. Darna) pallivitta (Lepidoptera: Limacodidae), is a serious invasive pest of agricultural products and a health hazard on the Hawaiian Islands first discovered in 2001. Nursery workers and homeowners have been stung by the caterpillars while handling their plants, especially rhapis palms (Rhapis sp.). Throughout its invaded range, it causes widespread damage, including the many cultivated and native palm species that have grown in Hawaii. Larvae contain urticating hairs that secrete a toxin, causing painful skin swelling and irritation on contact. Horticulture and nursery products impacted by the limacodid pest are estimated at $84.3 million (2018 value). Suppression efforts with pesticides and lure traps were ineffective, and the moth population continued to spread to major Hawaiian Islands (Hawaii, Kauai, Maui, Oahu). The introduction of specific biological control agents from the native region was thought to be the long-term solution for this invasive pest. Initial exploration in Indonesia and Thailand resulted in the introduction of a pupal ectoparasitoid, Nesolynx sp. (Hymenoptera: Eulophidae: Tetrastichinae), that was not specific. The oriental wasp, Aroplectrus dimerus Lin (Hymenoptera: Eulophidae: Eulophinae), idiobiont gregarious ectoparasitoid of the stinging nettle caterpillar, was introduced from Taiwan in 2004 for host specificity studies and biocontrol in Hawaii. Host range testing showed the parasitoid attacked only limacodid species, and it was approved for field release in 2010. The parasitoid identity, host specificity under containment facility conditions, reproductive performance, and colonization on the major infested sites were assessed. A total of 13,379 parasitoids were colonized on 162 release sites on four Hawaiian Islands. Evaluations were conducted using field surveys of larvae, pupal counts, and male lure traps. Field parasitism was thoroughly investigated on Oahu Island, averaging 18.9 ± 5.6% of 3923 collected larvae during 2010–2023. The numbers of male moths caught/trap/month were significantly reduced on Oahu Island (p < 0.05). Recently, the hyperparasitoid, Pediobius imbreus Walker (Hymenoptera: Eulophidae: Entedoninae), was detected, reducing the efficiency of A. dimerus in the field. The mean hyperparasitism of A. dimerus pupae was 27.3 ± 7.6% on Oahu Island. There was no detailed biological assessment for A. dimerus or its field evaluation available in scientific literature. Results were discussed regarding the potential use of A. dimerus in biocontrol elsewhere if the stinging nettle caterpillar was invaded in the future.
Vitamin D in Melanoma: Potential Role of Cytochrome P450 Enzymes
Authors: Ben-Eltriki Mohamed , Gayle Erysa J. , Paras Jhoanne M. , Nyame-Addo Louisa , Chhabra Manik , Deb Subrata
Published: April 2024

Vitamin D is a promising anticancer agent for the prevention and treatment of several cancers, including melanoma. Low 25-hydroxyvitamin D levels, a routinely used marker for vitamin D, have been suggested as one of the factors in the development and progression of melanoma. The parent vitamin D needs activation by cytochrome P450 (CYP) enzymes to exert its actions via the vitamin D receptor (VDR). This review discusses the role of vitamin D in melanoma and how CYP-mediated metabolism can potentially affect the actions of vitamin D. Through interacting with the retinoid X receptor, VDR signaling leads to anti-inflammatory, antioxidative, and anticancer actions. Calcitriol, the dihydroxylated form of vitamin D3, is the most active and potent ligand of VDR. CYP27A1, CYP27B1, and CYP2R1 are involved in the activation of vitamin D, whereas CYP24A1 and CYP3A4 are responsible for the degradation of the active vitamin D. CYP24A1, the primary catabolic enzyme of calcitriol, is overexpressed in melanoma tissues and cells. Several drug classes and natural health products can modulate vitamin D-related CYP enzymes and eventually cause lower levels of vitamin D and its active metabolites in tissues. Although the role of vitamin D in the development of melanoma is yet to be fully elucidated, it has been proposed that melanoma prevention may be significantly aided by increased vitamin D signaling. Furthermore, selective targeting of the catabolic enzymes responsible for vitamin D degradation could be a plausible strategy in melanoma therapy. Vitamin D signaling can be improved by utilizing dietary supplements or by modulating CYP metabolism. A positive association exists between the intake of vitamin D supplements and improved prognosis for melanoma patients. Further investigation is required to determine the function of vitamin D supplementation and specific enzyme targeting in the prevention of melanoma.
Approaches to Characterize and Quantify Extracellular Vesicle Surface Conjugation Efficiency
Authors: Goldbloom-Helzner Leora , Bains Harjn , Wang Aijun
Published: April 2024

Extracellular vesicles (EVs) are cell-secreted nanovesicles that play an important role in long-range cell–cell communication. Although EVs pose a promising alternative to cell-based therapy, targeted in vivo delivery still falls short. Many studies have explored the surface modification of EVs to enhance their targeting capabilities. However, to our knowledge, there are no standardized practices to confirm the successful surface modification of EVs or calculate the degree of conjugation on EV surfaces (conjugation efficiency). These pieces of information are essential in the reproducibility of targeted EV therapeutics and the determination of optimized conjugation conditions for EVs to see significant therapeutic effects in vitro and in vivo. This review will discuss the vast array of techniques adopted, technologies developed, and efficiency definitions made by studies that have calculated EV/nanoparticle surface conjugation efficiency and how differences between studies may contribute to differently reported conjugation efficiencies.
Approach to Determine the Limiting Shear Stress of Lubricants at High Pressures Based on Traction Mapping
Authors: Ma Zhaoqun , Zhao Yan , Han Yiming , Lou Wenjing , Li Shuai , Wang Xiaobo , Guo Feng , Liu Haichao
Published: April 2024

Typical lubricants behave in a non-Newtonian manner under conditions of high shear and high pressure, as is commonly observed in lubricated rolling/sliding contacts. To optimize and predict the friction therein, knowledge of the high-pressure rheological behaviors of lubricants and limiting shear stress (LSS) is essential. This study developed an approach for determining the LSS of lubricants based on friction mapping of rolling/sliding contacts, using a ball-on-disc traction machine. The main contribution lies in the introduction of a practical approach for the selection of a proper entrainment velocity for determining the LSS, with reduced thermal influences and near isothermal conditions. The proposed approach enables full film lubrication, while keeping the film as thin as possible to prevent excessive shear heating and, thus, thermal effects. The LSS of two lubricants, PAO40 and complex ester, has been measured at pressures ranging from 1.2 GPa to 1.7 GPa. A bilinear model has been used to describe the variation of LSS with pressure. The impact of entrainment velocity selection on the measurement of LSS is also discussed.
Ni-Cu Alloyed Austempered Ductile Iron Resistance to Multifactorial Wear
Authors: Wieczorek Andrzej Norbert
Published: April 2024

The paper provides a discussion on the results of studies of the effect exerted by combined degradation factors typical of four types of wear: abrasion, impact–abrasion, tribocorrosion, and impact–abrasion–corrosion, conducted for chain wheels made of Ni-Cu alloyed austempered ductile iron. The studies consisted of determining the content of retained austenite in the structure of the cast irons in question, establishing the measures of wear following wear testing, and identifying the basic surface degradation mechanisms observed in the chain wheels tested following multifactorial wear processes. The chain wheels made of ADI were found to have sustained the greatest damage under the impact–abrasion–corrosion (three-factor) wear scenario, while the wear was least advanced in the abrasion (one-factor) wear case. Another observation derived from the studies is that the combined effect of dynamic forces, corrosion, and quartz sand-based abrasives causes increased surface degradation in the cast iron grades taken into consideration compared to processes characterised by a reduced number of degradation factors (i.e., one- or two-factor wear processes). Additional hardness tests and XRD analyses revealed that a distinctive effect attributable to combined degradation factors on the surface hardness increased value and implied that bench testing was followed by phase transition.
Designing Prepregnation and Fused Filament Fabrication Parameters for Recycled PP- and PA-Based Continuous Carbon Fiber Composites
Authors: Baddour Marah , Garcia-Campà Ruth , Reyes Pablo , D’hooge Dagmar R. , Cardon Ludwig , Edeleva Mariya
Published: April 2024

Continuous carbon fiber (cCF)-based 3D-printed polymer composites are known for their excellent flexural properties; however, the optimization of the overall process is still desired, depending on the material types involved. Here, the improved manufacturing of cCF-based composites is reported, considering virgin polyamide (PA) and postindustrial waste polypropylene (PP), and the parameters affecting the material properties are evaluated. Firstly, the prepregnation technique was optimized to manufacture cCF polymer filaments with various fiber-to-polymer ratios. Secondly, the fused filament fabrication (FFF) technique was optimized. It was observed that the layer height needs to be sufficiently low for proper interlayer adhesion. The influence of the printing temperature is more complicated, with filaments characterized by a lower fiber-to-polymer ratio requiring a higher nozzle diameter and higher temperatures for efficient printing; and for lower diameters, the best flexural properties are observed for parts printed at lower temperatures, maintaining a high interspace distance. Plasma treatment of the cCF was also explored, as was annealing of the produced parts to enhance the flexural properties, the latter being specifically interesting for the PP-based composite due to a lower wetting caused by a higher viscosity, despite supportive interfacial interactions. Eventually, overall guidelines were formulated for the successful production of cCF-based composites.
Trametes versicolor Laccase-Based Magnetic Inorganic-Protein Hybrid Nanobiocatalyst for Efficient Decolorization of Dyes in the Presence of Inhibitors
Authors: Patel Sanjay K. S. , Gupta Rahul K. , Karuppanan Karthikeyan K. , Padhi Deepak K. , Ranganathan Sampathkumar , Paramanantham Parasuraman , Lee Jung-Kul
Published: April 2024

In the present investigation, an ecofriendly magnetic inorganic-protein hybrid system-based enzyme immobilization was developed using partially purified laccase from Trametes versicolor (TvLac), Fe3O4 nanoparticles, and manganese (Mn), and was successfully applied for synthetic dye decolorization in the presence of enzyme inhibitors. After the partial purification of crude TvLac, the specific enzyme activity reached 212 U∙mg total protein−1. The synthesized Fe3O4/Mn3(PO4)2-laccase (Fe3O4/Mn-TvLac) and Mn3(PO4)2-laccase (Mn-TvLac) nanoflowers (NFs) exhibited encapsulation yields of 85.5% and 90.3%, respectively, with relative activities of 245% and 260%, respectively, compared with those of free TvLac. One-pot synthesized Fe3O4/Mn-TvLac exhibited significant improvements in catalytic properties and stability compared to those of the free enzyme. Fe3O4/Mn-TvLac retained a significantly higher residual activity of 96.8% over that of Mn-TvLac (47.1%) after 10 reuse cycles. The NFs showed potential for the efficient decolorization of synthetic dyes in the presence of enzyme inhibitors. For up to five reuse cycles, Fe3O4/Mn-TvLac retained a decolorization potential of 81.1% and 86.3% for Coomassie Brilliant Blue R-250 and xylene cyanol, respectively. The synthesized Fe3O4/Mn-TvLac showed a lower acute toxicity towards Vibrio fischeri than pure Fe3O4 nanoparticles did. This is the first report of the one-pot synthesis of biofriendly magnetic protein-inorganic hybrids using partially purified TvLac and Mn.
Co and Co3O4 in the Hydrolysis of Boron-Containing Hydrides: H2O Activation on the Metal and Oxide Active Centers
Authors: Butenko Vladislav R. , Komova Oksana V. , Simagina Valentina I. , Lipatnikova Inna L. , Ozerova Anna M. , Danilova Natalya A. , Rogov Vladimir A. , Odegova Galina V. , Bulavchenko Olga A. , Chesalov Yuriy A. , Netskina Olga V.
Published: April 2024

This work focuses on the comparison of H2 evolution in the hydrolysis of boron-containing hydrides (NaBH4, NH3BH3, and (CH2NH2BH3)2) over the Co metal catalyst and the Co3O4-based catalysts. The Co3O4 catalysts were activated in the reaction medium, and a small amount of CuO was added to activate Co3O4 under the action of weaker reducers (NH3BH3, (CH2NH2BH3)2). The high activity of Co3O4 has been previously associated with its reduced states (nanosized CoBn). The performed DFT modeling shows that activating water on the metal-like surface requires overcoming a higher energy barrier compared to hydride activation. The novelty of this study lies in its focus on understanding the impact of the remaining cobalt oxide phase. The XRD, TPR H2, TEM, Raman, and ATR FTIR confirm the formation of oxygen vacancies in the Co3O4 structure in the reaction medium, which increases the amount of adsorbed water. The kinetic isotopic effect measurements in D2O, as well as DFT modeling, reveal differences in water activation between Co and Co3O4-based catalysts. It can be assumed that the oxide phase serves not only as a precursor and support for the reduced nanosized cobalt active component but also as a key catalyst component that improves water activation.
Spacing Analysis of Casting Dolly Windows for Tunnel Sidewall Lining Based on the Flow Characteristics of Freshly Mixed Concrete
Authors: Chi Zuoqiang , Shao Shuai , Wu Yimin , Yang Shuai , Zhou Zhuangzhuang
Published: April 2024

During the actual construction of tunnel sidewall lining, construction workers often use only one or two windows per layer for pouring in order to reduce the construction sequence, which often leads to a reduction in the quality of tunnel sidewall concrete pouring. Therefore, this study analysed the necessity of the window-by-window pouring of sidewall lining through the study of concrete flow characteristics of the tunnel sidewall lining pouring process, and the reasonable spacing of pouring windows was analysed. This study firstly verified the accuracy of the simulation parameters and the feasibility of the simulation method of the lining pouring process through indoor experiments and simulation analyses, and then it numerically simulated and analysed the flow of concrete during the lining pouring process of tunnel sidewalls. The following conclusions were made: the smaller the slump of the freshly mixed concrete, the higher the pumping flow rate; additionally, the shorter the one-time pouring distance, the smaller the spacing of the trolley feeding window should be. Furthermore, this study makes suggestions for the reasonable spacing of pouring trolleys under several working conditions.
The Influence of Materials on the Mechanical Properties of Ultra-High-Performance Concrete (UHPC): A Literature Review
Authors: Silva Mariana Lage da , Prado Lisiane Pereira , Félix Emerson Felipe , Sousa Alex Micael Dantas de , Aquino Davi Peretta
Published: April 2024

Ultra-high-performance concrete (UHPC) is a cementitious composite combining high-strength concrete matrix and fiber reinforcement. Standing out for its excellent mechanical properties and durability, this material has been widely recognized as a viable choice for highly complex engineering projects. This paper proposes (i) the review of the influence exerted by the constituent materials on the mechanical properties of compressive strength, flexural tensile strength, and elastic modulus of UHPC and (ii) the determination of optimal quantities of the constituent materials based on simplified statistical analyses of the developed database. The data search was restricted to papers that produced UHPC with straight steel fibers at a content of 2% by volume. UHPC mixture models were proposed based on graphical analyses of the relationship of constituent materials versus mechanical properties, aiming to optimize the material’s performance for each mechanical property. The results proved to be in accordance with the specifications present in the literature, characterized by high cement consumption, significant presence of fine materials, and low water-to-binder ratio. The divergences identified between the mixtures reflect how the constituent materials uniquely impact each mechanical property of the concrete. In general, fine materials were shown to play a significant role in increasing the compressive strength and flexural tensile strength of UHPC, while water and superplasticizers stood out for their influence on the material’s workability.
Comparative Analysis of Crosslinking Methods and Their Impact on the Physicochemical Properties of SA/PVA Hydrogels
Authors: Niewiadomski Konrad , Szopa Daniel , Pstrowska Katarzyna , Wróbel Paulina , Witek-Krowiak Anna
Published: April 2024

Hydrogels, versatile materials used in various applications such as medicine, possess properties crucial for their specific applications, significantly influenced by their preparation methods. This study synthesized 18 different types of hydrogels using sodium alginate (SA) and two molecular weights of polyvinyl alcohol (PVA). Crosslinking agents such as aqueous solutions of calcium (Ca2+) and copper (Cu2+) ions and solutions of these ions in boric acid were utilized. The hydrogels were subjected to compression strength tests and drying kinetics analysis. Additionally, six hydrogel variants containing larger PVA particles underwent Fourier-transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) post-drying. Some samples were lyophilized, and their surface morphology was examined using scanning electron microscopy (SEM). The results indicate that the choice of crosslinking method significantly impacts the physicochemical properties of the hydrogels. Crosslinking in solutions with higher concentrations of crosslinking ions enhanced mechanical properties and thermal stability. Conversely, using copper ions instead of calcium resulted in slower drying kinetics and reduced thermal stability. Notably, employing boric acid as a crosslinking agent for hydrogels containing heavier PVA molecules led to considerable improvements in mechanical properties and thermal stability.
Global Weak Solution for Phase Transition Equations with Polarization
Authors: Li Fangfang , Ma Yansheng
Published: April 2024

This paper deals with a phase transition model with polarization which describes the thermodynamic, electromagnetic, and polarization properties of ferromagnetic–ferroelectric materials. The existence of the global weak solution for the phase transition equations with polarization is rigorously established through the viscosity vanishing argument.
A Generalized Residual-Based Test for Fractional Cointegration in Panel Data with Fixed Effects
Authors: Olaniran Saidat Fehintola , Olaniran Oyebayo Ridwan , Allohibi Jeza , Alharbi Abdulmajeed Atiah , Ismail Mohd Tahir
Published: April 2024

Asymptotic theories for fractional cointegrations have been extensively studied in the context of time series data, with numerous empirical studies and tests having been developed. However, most previously developed testing procedures for fractional cointegration are primarily designed for time series data. This paper proposes a generalized residual-based test for fractionally cointegrated panels with fixed effects. The test’s development is based on a bivariate panel series with the regressor assumed to be fixed across cross-sectional units. The proposed test procedure accommodates any integration order between [0,1], and it is asymptotically normal under the null hypothesis. Monte Carlo experiments demonstrate that the test exhibits better size and power compared to a similar residual-based test across varying sample sizes.
Optimizing Allocation Rules in Discrete and Continuous Discriminant Analysis
Authors: Ferreira Dário , Ferreira Sandra S.
Published: April 2024

This paper presents an approach for the study of probabilistic outcomes in experiments with multiple possible results. An approach to obtain confidence ellipsoids for the vector of probabilities, which represents the likelihood of specific results, for both discrete and continuous discriminant analysis, is presented. The obtention of optimal allocation rules, in order to reduce the allocation costs is investigated. In the context of discrete discriminant analysis, the approach focuses on assigning elements to specific groups in an optimal way. Whereas in the continuous case, the approach involves determining the regions where each action is the optimal choice. The effectiveness of the proposed approach is examined with two numerical applications. One of them uses real data, while the other one uses simulated data.
Multi-Objective Optimization of Cell Voltage Based on a Comprehensive Index Evaluation Model in the Aluminum Electrolysis Process
Authors: Xu Chenhua , Zhang Wenjie , Liu Dan , Cen Jian , Xiong Jianbin , Luo Guojuan
Published: April 2024

In the abnormal situation of an aluminum electrolysis cell, the setting of cell voltage is mainly based on manual experience. To obtain a smaller cell voltage and optimize the operating parameters, a multi-objective optimization method for cell voltage based on a comprehensive index evaluation model is proposed. Firstly, a comprehensive judgment model of the cell state based on the energy balance, material balance, and stability of the aluminum electrolysis process is established. Secondly, a fuzzy neural network (FNN) based on the autoregressive moving average (ARMA) model is designed to establish the cell-state prediction model in order to finish the real-time monitoring of the process. Thirdly, the optimization goal of the process is summarized as having been met when the difference between the average cell voltage and the target value reaches the minimum, and the condition of the cell is excellent. And then, the optimization setting model of cell voltage is established under the constraints of the production and operation requirements. Finally, a multi-objective antlion optimization algorithm (MOALO) is used to solve the above model and find a group of optimized values of the electrolysis cell, which is used to realize the optimization control of the cell state. By using actual production data, the above method is validated to be effective. Moreover, optimized operating parameters are used to verify the prediction model of cell voltage, and the cell state is just excellent. The method is also applied to realize the optimization control of the process. It is of guiding significance for stabilizing the electrolytic aluminum production and achieving energy saving and consumption reduction.