bluuebunny/crossref_metadata_2025 huggingface dataset:
Small Molecule Therapeutics in the Pipeline Targeting for Triple-Negative Breast Cancer: Origin, Challenges, Opportunities, and Mechanisms of Action
Authors: James Nneoma , Owusu Esther , Rivera Gildardo , Bandyopadhyay Debasish
Published: June 2024

Triple-negative breast cancer (TNBC) cells are devoid of estrogen receptors (ERs), progesterone receptor (PRs), and human epidermal growth factor receptor 2 (HER2), and it (TNBC) counts for about 10–15% of all breast cancers. TNBC is highly invasive, having a faster growth rate and a higher risk of metastasis and recurrence. Still, chemotherapy is one of the widely used options for treating TNBC. This study reviewed the histological and molecular characterization of TNBC subtypes, signaling pathways that are aberrantly expressed, and small molecules targeting these pathways, as either single agents or in combination with other therapeutic agents like chemotherapeutics, immunotherapeutics, and antibody–drug conjugates; their mechanisms of action, challenges, and future perspectives were also reviewed. A detailed analytical review was carried out using the literature collected from the SciFinder, PubMed, ScienceDirect, Google Scholar, ACS, Springer, and Wiley databases. Several small molecule inhibitors were found to be therapeutics for treating TNBC. The mechanism of action and the different signaling pathways through which the small molecules exert their effects were studied, including clinical trials, if reported. These small molecule inhibitors include buparlisib, everolimus, vandetanib, apatinib, olaparib, salidroside, etc. Some of the signaling pathways involved in TNBC, including the VEGF, PARP, STAT3, MAPK, EGFR, P13K, and SRC pathways, were discussed. Due to the absence of these biomarkers, drug development for treating TNBC is challenging, with chemotherapy being the main therapeutic agent. However, chemotherapy is associated with chemoresistance and a high toxicity to healthy cells as side effects. Hence, there is a continuous demand for small-molecule inhibitors that specifically target several signaling pathways that are abnormally expressed in TNBC. We attempted to include all the recent developments in this field. Any omission is truly unintentional.
O-GlcNAc Modification Is a Promising Therapeutic Target for Diabetic Retinopathy
Authors: Dong Wenkang , Imdad Laraib , Xu Shengnan , Wang Yinli , Liu Chengzhi , Song Shiyu , Li Zechuan , Kong Ying , Kong Li , Ren Xiang
Published: June 2024

Diabetic retinopathy (DR) is a very serious diabetes complication. Changes in the O-linked N-acetylglucosamine (O-GlcNAc) modification are associated with many diseases. However, its role in DR is not fully understood. In this research, we explored the effect of O-GlcNAc modification regulation by activating AMP-activated protein kinase (AMPK) in DR, providing some evidence for clinical DR treatment in the future. Bioinformatics was used to make predictions from the database, which were validated using the serum samples of diabetic patients. As an in vivo model, diabetic mice were induced using streptozotocin (STZ) injection with/without an AMPK agonist (metformin) or an AMPK inhibitor (compound C) treatment. Electroretinogram (ERG) and H&E staining were used to evaluate the retinal functional and morphological changes. In vitro, 661 w cells were exposed to high-glucose conditions, with or without metformin treatment. Apoptosis was evaluated using TUNEL staining. The protein expression was detected using Western blot and immunofluorescence staining. The angiogenesis ability was detected using a tube formation assay. The levels of O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA) in the serum changed in the DR patients in the clinic. In the diabetic mice, the ERG wave amplitude and retinal thickness decreased. In vitro, the apoptotic cell percentage and Bax expression were increased, and Bcl2 expression was decreased in the 661 w cells under high-glucose conditions. The O-GlcNAc modification was increased in DR. In addition, the expression of GFAT/TXNIP O-GlcNAc was also increased in the 661 w cells after the high-glucose treatment. Additionally, the Co-immunoprecipitation(CO-IP) results show that TXNIP interacted with the O-GlcNAc modification. However, AMPK activation ameliorated this effect. We also found that silencing the AMPKα1 subunit reversed this process. In addition, the conditioned medium of the 661 w cells may have affected the tube formation in vitro. Taken together, O-GlcNAc modification was increased in DR with photoreceptor cell degeneration and neovascularization; however, it was reversed after activating AMPK. The underlying mechanism is linked to the GFAT/TXNIP-O-GlcNAc modification signaling axis. Therefore, the AMPKα1 subunit plays a vital role in the process.
Network Structure of Online Customer Reviews and Online Hotel Reviews: A Systematic Literature Review
Authors: Pestana Maria Helena , Gageiro Manuel , Santos José António C. , Santos Margarida Custódio
Published: June 2024

This study conducts a bibliometric analysis of online customer and hotel review research, aiming to provide insights into where each field comes from, stands now and ought to go in the future. In particular, this study examines how the existing research on online customer reviews can benefit future hotel review research. Data collected from Web-of-Science and Scopus created an expanded network of 797 core articles and 19,374 citations to identify intellectual structures, developing trends, and future research gaps. This study offers a visual overview of journals, institutions, countries, research themes and authors to assess the overall directions hotels can take. It underscores the necessity for rigorous and relevant research amid the proliferation of online reviews and emphasises the imperative for academia to bridge the gap between theoretical insights and practical applications within the dynamic tourism industry. This study provides researchers and industry professionals with useful tools to understand and deal with the complexities of online reviews. It also highlights the important role these reviews play in shaping the future of tourism strategies.
Production Scheduling Based on a Multi-Agent System and Digital Twin: A Bicycle Industry Case
Authors: Siatras Vasilis , Bakopoulos Emmanouil , Mavrothalassitis Panagiotis , Nikolakis Nikolaos , Alexopoulos Kosmas
Published: June 2024

The emerging digitalization in today’s industrial environments allows manufacturers to store online knowledge about production and use it to make better informed management decisions. This paper proposes a multi-agent framework enhanced with digital twin (DT) for production scheduling and optimization. Decentralized scheduling agents interact to efficiently manage the work allocation in different segments of production. A DT is used to evaluate the performance of different scheduling decisions and to avoid potential risks and bottlenecks. Production managers can supervise the system’s decision-making processes and manually regulate them online. The multi-agent system (MAS) uses asset administration shells (AASs) for data modelling and communication, enabling interoperability and scalability. The framework was deployed and tested in an industrial pilot coming from the bicycle production industry, optimizing and controlling the short-term production schedule of the different departments. The evaluation resulted in a higher production rate, thus achieving higher production volume in a shorter time span. Managers were also able to coordinate schedules from different departments in a dynamic way and achieve early bottleneck detection.
Binding Analysis of Sf-SR-C MAM Domain and Sf-FGFR Ectodomain to Vip3Aa
Authors: Wang Chenghai , Li Min , Chen Xiling , Fan Shilong , Lan Jun
Published: June 2024

Bacillus thuringiensis Vip3Aa has been widely used in transgenic crops to resist the erosion of insects. The Scavenger Receptor-C (SR-C) and Fibroblast Growth Factor Receptor (FGFR) of Spodoptera frugiperda (Sf-SR-C and Sf-FGFR) have formerly been identified as the cell receptors of Vip3Aa. However, the interaction mechanism of Vip3Aa binding to Sf-SR-C or Sf-FGFR is still unknown. Here, we purified the MAM domain of Sf-SR-C (Sf-MAM) and the Sf-FGFR ectodomain expressed extracellularly by Sf9 cells. We then solved the crystal structure of the Sf-MAM domain. Structure docking analysis of the Sf-MAM and Vip3Aa C-terminal domain (CTD) excluded the possibility of the two proteins binding. A further surface plasmon resonance (SPR) assay also revealed that the Sf-MAM and Sf-FGFR ectodomain could not bind to the Vip3Aa protein. Our results have raised the urgency of determining the authentic cell receptor for Vip3Aa.
Bee-Associated Beneficial Microbes—Importance for Bees and for Humans
Authors: Todorov Svetoslav Dimitrov , Alves Marcos Vinício , Bueno Gisana Cristina Alves , Alves Virgínia Farias , Ivanova Iskra Vitanova
Published: June 2024

Bees are one of the best-known and, at the same time, perhaps the most enigmatic insects on our planet, known for their organization and social structure, being essential for the pollination of agricultural crops and several other plants, playing an essential role in food production and the balance of ecosystems, being associated with the production of high-value-added inputs, and a unique universe in relation to bees’ microbiota. In this review, we summarize information regarding on different varieties of bees, with emphasis on their specificity related to microbial variations. Noteworthy are fructophilic bacteria, a lesser-known bacterial group, which use fructose fermentation as their main source of energy, with some strains being closely related to bees’ health status. The beneficial properties of fructophilic bacteria may be extendable to humans and other animals as probiotics. In addition, their biotechnological potential may ease the development of new-generation antimicrobials with applications in biopreservation. The concept of “One Health” brings together fundamental and applied research with the aim of clarifying that the connections between the different components of ecosystems must be considered part of a mega-structure, with bees being an iconic example in that the healthy functionality of their microbiota is directly and indirectly related to agricultural production, bee health, quality of bee products, and the functional prosperity for humans and other animals. In fact, good health of bees is clearly related to the stable functionality of ecosystems and indirectly relates to humans’ wellbeing, a concept of the “One Health”.
Hospitalizations for Acute Otitis and Sinusitis in Patients Living with HIV: A Retrospective Analysis of a Tertiary Center in Romania
Authors: Pleșca Vlad Ștefan , Miron Victor Daniel , Marinescu Adrian Gabriel , Drăgănescu Anca Cristina , Pleșca Anca Doina , Săndulescu Oana , Voiosu Cătălina , Hainăroșie Răzvan , Streinu-Cercel Anca
Published: June 2024

Background/Objectives: Acute or chronic ear, nose and throat (ENT) conditions in people living with HIV can lead to hospitalization and affect their quality of life. The aim of our study was to determine the frequency and characteristics of hospitalizations for acute sinusitis (AS) and acute otitis (AO) in people living with HIV. Methods: We performed a retrospective analysis over the course of six years (from January 2018 to December 2023), assessing all hospitalizations for AS and/or AO occurring in patients living with HIV, at the largest infectious diseases hospital in Romania. Results: We identified a total of 179 cases, among which 149 cases (83.2%) were attributed to AS and 41 cases (22.9%) were due to AO. Among cases of AS, maxillary sinuses were most frequently involved (n = 140/149, 94.0%), and among cases of AO, acute congestive otitis media (n = 14, 34.1%) and acute purulent otitis media (n = 13, 31.7%) were the most common forms. The underlying HIV infection was classified as stage C3 in 57.5% of cases. In 19.6% of cases, it was possible to identify either the trigger or the etiological agent, and the most frequent bacterial pathogens were Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae and Pseudomonas aeruginosa. Conclusions: In conclusion, this study highlights that hospitalizations due to acute sinus and ear involvement are not isolated events in people living with HIV. A prospective follow-up is needed to gain a deeper and more dynamic understanding of how ENT health is affected in people with HIV infection. Furthermore, promoting prevention through vaccination may reduce to a certain extent the burden of ENT infections in this population.
Development of High-Sensitivity Thermoplastic Polyurethane/Single-Walled Carbon Nanotube Strain Sensors through Solution Electrospinning Process Technique
Authors: Kotrotsos Athanasios , Syrmpopoulos Nikolaos , Gavathas Prokopios , Moica Sorina , Kostopoulos Vassilis
Published: June 2024

In this study, nanofibers obtained through the electrospinning process are explored for strain-sensing applications. Thermoplastic polyurethane (TPU) flexible structures were fabricated using the solution electrospinning process (SEP) technique. Subsequently, these structures were nanomodified with single-walled carbon nanotubes (SWCNTs) through immersion into an ultrasonicated suspension containing 0.3 wt% SWCNTs. The nanomodification aimed to impart an electrically conductive network to the structures. Micro-tensile tests and electrical resistance measurements were conducted to characterize the apparent mechanical and electrical properties, respectively. The fabricated structures demonstrated potential as wearable strain sensors for monitoring changes in strain across various applications. The samples exhibited excellent performance, high sensitivity, outstanding mechanical properties, and a broad stretching range. Scanning electron microscopy (SEM) observations provided qualitative insights into the activated conductive pathways during operation.
Intervention Hypothesis for Training with Whole-Body Vibration to Improve Physical Fitness Levels: An Umbrella Review
Authors: Petrigna Luca , Amato Alessandra , Sortino Martina , Trovato Bruno , Zanghì Marta , Roggio Federico , Musumeci Giuseppe
Published: June 2024

Whole-body vibration (WBV) is a training modality, and it seems to be a safe and efficient exercise especially to improve different aspects of physical fitness in different populations. The protocols for WBV are still not standardized. The difficulty in comparing the data confuses the real efficacy of this instrument. Consequently, the objective of this umbrella review is to analyze the protocols previously adopted and eventually to propose a standard operating procedure for WBV training. Systematic review and meta-analysis of randomized controlled trials on WBV were searched on the electronic databases PubMed, Web of Science, and Scopus until 18 March 2024. A quality assessment of the studies included has been performed. A total of 20 studies were included in this umbrella review and frequency, magnitude, and amplitude intensity data were recorded. Detailed information about the protocols (static or dynamic exercises, barefoot or with shoes, intensity duration, weekly frequency, and vibration characteristics) was also collected. WBV presents widely different protocols. Consequently, a standard operating procedure has not been proposed for WBV training. A hypothesis of intervention was instead written in which parameters for frequency, amplitude, acceleration, and training mode were proposed.
The CARD9 Gene in Koalas (Phascolarctos cinereus): Does It Play a Role in the Cryptococcus–Koala Interaction?
Authors: Newton Hannah P. , Higgins Damien P. , Casteriano Andrea , Wright Belinda R. , Krockenberger Mark B. , Miranda Luisa H. M.
Published: June 2024

Cryptococcus is a genus of fungal pathogens that can infect and cause disease in a range of host species and is particularly prominent in koalas (Phascolarctos cinerus). Like other host species, koalas display a range of outcomes upon exposure to environmental Cryptococcus, from external nasal colonization to asymptomatic invasive infection and, in rare cases, severe clinical disease resulting in death. Host factors contributing to these varied outcomes are poorly understood. Due to their close relationship with eucalypt trees (a key environmental niche for Cryptococcus gattii) and suspected continual exposure to the pathogen, koalas provide a unique opportunity to examine host susceptibility in natural infections. Caspase recruitment domain-containing protein 9 (CARD9) is a key intracellular signaling protein in the fungal innate immune response. Humans with mutations in CARD9 succumb to several different severe and chronic fungal infections. This study is the first to sequence and explore CARD9 variation in multiple koalas using Sanger sequencing. Four CARD9 exons were successfully sequenced in 22 koalas from a New South Wales, Australia population. We found minimal variation between koalas across all four exons, an observation that was also made when CARD9 sequences were compared between koalas and six other species, including humans and mice. Ten single-nucleotide polymorphisms (SNP) were identified in this study and explored in the context of cryptococcal exposure outcomes. While we did not find any significant association with variation in cryptococcal outcomes, we found a high degree of conservation between species at several SNP loci that requires further investigation. The findings from this study lay the groundwork for further investigations of CARD9 and Cryptococcus both in koalas and other species, and highlight several considerations for future studies.
Mechanistic Insights into the Neurotoxicity of 2,5-Dimethoxyphenethylamines (2C) and Corresponding N-(2-methoxybenzyl)phenethylamine (NBOMe) Drugs
Authors: Gil-Martins Eva , Cagide-Fagín Fernando , Martins Daniel , Borer Ana , Barbosa Daniel José , Fernandes Carlos , Chavarria Daniel , Remião Fernando , Borges Fernanda , Silva Renata
Published: June 2024

Substituted phenethylamines including 2C (2,5-dimethoxyphenethylamines) and NBOMe (N-(2-methoxybenzyl)phenethylamines) drugs are potent psychoactive substances with little to no knowledge available on their toxicity. In the present in vitro study, we explored the mechanisms underlying the neurotoxicity of six substituted phenethylamines: 2C-T-2, 2C-T-4, 2C-T-7 and their corresponding NBOMes. These drugs were synthesized and chemically characterized, and their cytotoxicity (0–1000 μM) was evaluated in differentiated SH-SY5Y cells and primary rat cortical cultures, by the NR uptake and MTT reduction assays. In differentiated SH-SY5Y cells, mitochondrial membrane potential, intracellular ATP and calcium levels, reactive oxygen species production, and intracellular total glutathione levels were also evaluated. All the tested drugs exhibited concentration-dependent cytotoxic effects towards differentiated SH-SY5Y cells and primary rat cortical cultures. The NBOMe drugs presented higher cytotoxicity than their counterparts, which correlates with the drug’s lipophilicity. These cytotoxic effects were associated with mitochondrial dysfunction, evident through mitochondrial membrane depolarization and lowered intracellular ATP levels. Intracellular calcium imbalance was observed for 2C-T-7 and 25T7-NBOMe, implying a disrupted calcium regulation. Although reactive species levels remained unchanged, a reduction in intracellular total GSH content was observed. Overall, these findings contribute to a deeper understanding of these drugs, shedding light on the mechanisms underpinning their neurotoxicity.
Controversies and Advances in the Personalized Surgical Treatment of Cervical Cancer
Authors: Pergialiotis Vasilios , Rodolakis Ioannis , Rodolakis Alexandros , Thomakos Nikolaos
Published: June 2024

Cervical cancer represents a global health issue as it is mostly encountered in women of reproductive age, while at the same time, survival outcomes seem to have remained constant during the last two decades. The need to implement fertility-sparing strategies as well as to decrease the morbidity that accompanies radical treatment has been extensively studied. During the last decade, several randomized clinical trials have been released, resulting in significant advances in the surgical treatment of early-stage disease. At the same time, evidence about the surgical treatment of advanced-stage disease as well as recurrent disease has gradually appeared and seems to be promising, thus leading the point forward towards personalized medicine that will remove the surgical barriers that seem concrete in our era. Nevertheless, the discrepancies in perioperative morbidity and survival outcomes that were observed among published studies raise several questions. In the present article, we chose to review the gray fields in the surgical treatment of early-stage and advanced-stage cervical cancer. Studies that are based on strong evidence that support current clinical practice are compared to smaller cohorts that present novel data that may form the basis for future research, and issues that remain poorly explored are discussed in an effort to help establish a consensus for future research development.
The Role of Amino Acid Glycine on Cardiovascular Health and Its Beneficial Effects: A Narrative Review
Authors: Quintanilla-Villanueva Gabriela , Rodríguez-Delgado Melissa , Villarreal-Chiu Juan , Blanco-Gámez Edgar , Luna-Moreno Donato
Published: June 2024

Glycine, a simple amino acid, is not only essential due to its potential insufficiency in vivo, but also has significant metabolic functions. It serves as a crucial building block for proteins. At the same time, as a bioactive molecule, it regulates gene expression for cytoprotection, protein configuration and activity, and other critical biological processes, including glutathione synthesis. The intriguing, beneficial effects of glycine in medical applications have piqued the research community’s interest in recent decades. This work delves into the compelling discoveries about the pivotal role of glycine in cardiovascular health and its intricate mechanisms of action for alleviating several medical conditions. Glycine’s broad spectrum of impact spans numerous diseases, encompassing not only acute myocardial infarction, aortic dissection, and cardiac hypertrophy, but also transplant rejections of aortic allografts, insulin resistance, and endothelial dysfunction, thereby providing a comprehensive understanding of its medical applications.
Quality Improvement of Urban Public Space from the Perspective of the Flâneur
Authors: Wang Li , Liu Xiao , Zheng Hao , Caneparo Luca
Published: June 2024

As the quality of public space has become significant for urban development, the creation of high-quality public spaces is becoming increasingly important. Since the implementation of urban renewal policies, an increasing number of buildings have emerged, creating new types of public spaces. Compared to original public spaces, new public spaces are more open, flexible, and diverse. The design of public spaces is closely related to users and the flâneur can precisely serve as a user and observer to conduct in-depth research. So, our study was conducted under the identity of the flâneur, focusing on two cases in Guangzhou. The flâneur completes the data collection through two methods. Static research involves observing and taking photos, whereas dynamic research involves interviews and questionnaires. This study analysed three aspects: the group category, behavioural diversity, and activity time and evaluated the public space using the NPS scale. The study found that the recommendation rate of new urban public spaces is higher than that of original public spaces. The study also found that original public spaces need to be improved in four ways: equipping furniture facilities, improving traffic congestion, increasing blue-green spaces, and establishing artistic spaces. New urban public spaces need to make efforts to create more interactive spaces and increase stagnation points.
Matched Relationships and Mechanisms of Water and Land Resources in Karst Mountainous Areas: A Review
Authors: Pang Xiaofei , Xie Binggeng , Zhang Xuemao , Xie Jing , Xiao Jianyong
Published: June 2024

The matching relationship between water and land resources in the karst mountains is closely related to regional ecological and environmental security, human well-being, and high-quality socio-economic development. Based on a massive literature review, this review systematically summarizes the research overview, development process, and matching mechanism of karst water and land resources. The results show the following: (1) Since 1990, the number of publications on karst water and land resources has shown a steady upward trend, with the journals covering multiple fields, characterized by multidisciplinary and interdisciplinary features. (2) The matching relationship between water and land resources in karst mountainous areas has experienced three stages: “single element–binary matching–multiple coupling”. It reveals the evolutionary process from focusing on the single internal system of water and land resources to focusing on the mutual matching relationship between water and land resources, and then to the study of multiple coupling between water and land resources system and other external systems. (3) The internal coordinated development of the water and land resources system in karst mountainous areas depends on the joint interactions of natural, economic, and social factors, while the external matching mainly focuses on the mechanism around the three aspects of water and land resources and agricultural production, ecological environment, and economic and social development. Furthermore, the review proposes that future research should explore the matching of water and land resources in karst mountainous areas through theoretical framework construction, model innovation, scale refinement, and mechanism analysis. The expected results will provide a scientific reference for advancing theoretical research on karst water and land resources and optimizing their management.
Study on the Relationship between Port Governance and Terminal Operation System for Smart Port: Japan Case
Authors: Inutsuka Hideyo , Ichimura Kinya , Sugimura Yoshihisa , Yoshie Muneo , Shinoda Takeshi
Published: June 2024

Background: To improve port productivity, safety, and sustainability, the use of information and communication technology is being promoted as a smart port. The utilization of a terminal operation system (TOS) is important for advanced port operations, and it is necessary to organize the issues and characteristics of the TOS. Methods: The characteristics of TOSs introduced in Japan and those widely introduced in Europe and Southeast Asia will be investigated and discussed according to the port management system in Japan. Results: Japanese TOSs are characterized by a lack of automated functions, such as ship loading plans, and by the fact that they are designed to allow the crane driver to select the order of operations, which may be attributed to a system wherein stakeholders are segmented and on-site decisions are emphasized. The promotion of smart ports in Japanese-style ports requires a system for information linkage between stakeholders. Conclusions: TOS capabilities for smart ports should be implemented according to the characteristics of port management in each region, and the studies conducted in this paper are useful in examining port system implementation strategies.
Dichloro-μ2,μ2-naphthalene-1,8-diyl-bis(N,N,N′,N′-tetramethylethylenediamino)tetracopper(I)
Authors: Ray Matthew J. , Saviantoni Maria Laura , Slawin Alexandra M. Z. , Cordes David B. , Kilian Petr
Published: June 2024

A highly reactive dicuprate/CuCl aggregate, Nap(Cu4Cl2)(TMEDA)2 (2, Nap = naphthalene-1,8-diyl, TMEDA = tetramethylethylenediamine), was synthesized by the reaction of 1,8-dilithionaphthalene(TMEDA)2 with four equivalents of CuCl. The X-ray crystal structure of this complex shows that the four copper atoms form a bent parallelogram-shaped core, with terminally bonded chlorine atoms. The naphthalene ring is bonded through carbons in the 1 and 8 positions (peri-positions), each bridging two copper atoms.
A New Method for the Synthesis of 1-(1-Isocyanoethyl)adamantane
Authors: Pitushkin Dmitry , Butov Gennady
Published: June 2024

A novel single-step method has been developed for the synthesis of 1-(1-isocyanoethyl)adamantane from 1-(1-adamantylethyl)amine, chloroform, and t-BuOK, in a dichloromethane/tert-butanol (1:1) medium, yielding 92%, which is 27% higher compared to the known method, without the use of highly toxic compounds. The product was characterized using 1H and 13C NMR spectroscopy, GC-MS, and elemental analysis.
Correction: Rajabi et al. Solvent-Free Preparation of 1,8-Dioxo-Octahydroxanthenes Employing Iron Oxide Nanomaterials. Materials 2019, 12, 2386
Authors: Rajabi Fatemeh , Abdollahi Mohammad , Diarjani Elham Sadat , Osmolowsky Mikhail G. , Osmolovskaya Olga M. , Gómez-López Paulette , Puente-Santiago Alain R. , Luque Rafael
Published: June 2024

It has been brought to the attention of the Editorial Office that Figure 1 in the original publication [...]
Effect of Carbon Fiber Paper with Thickness Gradient on Electromagnetic Shielding Performance of X-Band
Authors: Liu Zhi , Song Meiping , Liang Weiqi , Gao Xueping , Zhu Bo
Published: June 2024

Flexible paper-based materials play a crucial role in the field of flexible electromagnetic shielding due to their thinness and controllable shape. In this study, we employed the wet paper forming technique to prepare carbon fiber paper with a thickness gradient. The electromagnetic shielding performance of the carbon fiber paper varies with the ladder-like thickness distribution. Specifically, an increase in thickness gradient leads to higher reflectance of the carbon fiber paper. Within the X-band frequency range (8.2–12.4 GHz), reflectivity decreases as electromagnetic wave frequency increases, indicating enhanced penetration of electromagnetic waves into the interior of the carbon fiber paper. This enhancement is attributed to an increased fiber content per unit area resulting from a greater thickness gradient, which further enhances reflection loss and promotes internal multiple reflections and scattering effects, leading to increased absorption loss. Notably, at a 5 mm thickness, our carbon fiber paper exhibits an impressive average overall shielding performance, reaching 63.46 dB. Moreover, it exhibits notable air permeability and mechanical properties, thereby assuming a pivotal role in the realm of flexible wearable devices in the foreseeable future.
A Study on Ammonium Chloride Dendrite Tip Kinetics: The Importance of the Solid–Liquid Density Change and Interfacial Kinetics
Authors: Alrasheedi Nashmi , Stefan-Kharicha Mihaela , Sari Ibrahim , Ahmadein Mahmoud , Kharicha Abdellah
Published: June 2024

Ammonium chloride (NH4Cl) has been extensively studied as a transparent analogue for investigating the solidification of metals due to its distinctive properties and the simplicity of the experimentation. Furthermore, NH4Cl exhibits a striking resemblance in solidification behavior to the majority of binary eutectic alloy systems, rendering it a valuable model for studying phase transition phenomena. Experiments conducted on ammonium chloride are frequently employed to validate numerical models for predicting grain structures, macrosegregation, and the columnar-to-equiaxed transition (CET). This latter phenomenon arises due to differences in the velocities of columnar dendrite tips and the liquidus isosurface. However, the kinetics of dendrite tip growth, as a function of supersaturation, remains poorly understood for this commonly used alloy. The objective of this study was to utilize the available experimental data in conjunction with Ivantsov correlations to shed light on the ambiguous kinetics. The results indicate that when considering the crystal–melt density ratio, the Ivantsov solution offers a good correlation. Furthermore, incorporating a moderate interfacial kinetic coefficient enhances the correlations further. This correlation can be implemented in numerical models, which will aid in the determination of the columnar front, the columnar-to-equiaxed transition, and the equiaxed growth velocities.
Nondestructive Inspection and Quantification of Select Interface Defects in Honeycomb Sandwich Panels
Authors: Khademi Mahsa , Pulipati Daniel P. , Jack David A.
Published: June 2024

Honeycomb sandwich panels are utilized in many industrial applications due to their high bending resistance relative to their weight. Defects between the core and the facesheet compromise their integrity and efficiency due to the inability to transfer loads. The material system studied in the present paper is a unidirectional carbon fiber composite facesheet with a honeycomb core with a variety of defects at the interface between the two material systems. Current nondestructive techniques focus on defect detectability, whereas the presented method uses high-frequency ultrasound testing (UT) to detect and quantify the defect geometry and defect type. Testing is performed using two approaches, a laboratory scale immersion tank and a novel portable UT system, both of which utilize only single-side access to the part. Coupons are presented with defects spanning from 5 to 40 mm in diameter, whereas defects in the range of 15–25 mm and smaller are considered below the detectability limits of existing inspection methods. Defect types studied include missing adhesive, unintentional foreign objects that occur during the manufacturing process, damaged core, and removed core sections. An algorithm is presented to quantify the defect perimeter. The provided results demonstrate successful defect detection, with an average defect diameter error of 0.6 mm across all coupons studied in the immersion system and 1.1 mm for the portable system. The best accuracy comes from the missing adhesive coupons, with an average error of 0.3 mm. Conversely, the worst results come from the missing or damaged honeycomb coupons, with an error average of 0.7 mm, well below the standard detectability levels of 15–25 mm.
Mechanical Properties of Alkasite Material with Different Curing Modes and Simulated Aging Conditions
Authors: Negovetic Mandic Visnja , Plancak Laura , Marovic Danijela , Tarle Zrinka , Trutina Gavran Milena , Par Matej
Published: June 2024

This study aimed to evaluate the micro-mechanical and macro-mechanical properties of self-cured and light-cured alkasite and to investigate how accelerated degradation in acidic, alkaline, and ethanol solutions affects the macro-mechanical properties of self-cured and light-cured alkasite. The specimens of the alkasite material (Cention Forte, Ivoclar Vivadent) were prepared according to the following three curing modes: (1) light-cured immediately, (2) light-cured after a 5-min delay, and (3) self-cured. Microhardness was tested before and after immersion in absolute ethanol to indirectly determine crosslink density, while flexural strength and flexural modulus were measured using a three-point bending test after accelerated aging in the following solutions: (1) lactic acid solution (pH = 4.0), (2) NaOH solution (pH = 13.0), (3) phosphate-buffered saline solution (pH = 7.4), and (4) 75% ethanol solution. The data were statistically analyzed using a two-way ANOVA and Tukey post hoc test. The results showed that the microhardness, flexural strength, and flexural modulus were significantly lower in self-cured specimens compared to light-cured specimens. A 5-min delay between the extrusion of the material from the capsule and light curing had no significant effect on any of the measured properties. A significant effect of the accelerated aging solutions on macro-mechanical properties was observed, with ethanol and alkaline solutions having a particularly detrimental effect. In conclusion, light curing was preferable to self-curing, as it resulted in significantly better micro- and macro-mechanical properties, while a 5-min delay between mixing the capsule and light curing had no negative effects.
Exploring In Vivo Pulmonary and Splenic Toxicity Profiles of Silicon Quantum Dots in Mice
Authors: Cristian Roxana-Elena , Balta Cornel , Herman Hildegard , Ciceu Alina , Trica Bogdan , Sbarcea Beatrice G. , Miutescu Eftimie , Hermenean Anca , Dinischiotu Anca , Stan Miruna S.
Published: June 2024

Silicon-based quantum dots (SiQDs) represent a special class of nanoparticles due to their low toxicity and easily modifiable surface properties. For this reason, they are used in applications such as bioimaging, fluorescent labeling, drug delivery, protein detection techniques, and tissue engineering despite a serious lack of information on possible in vivo effects. The present study aimed to characterize and evaluate the in vivo toxicity of SiQDs obtained by laser ablation in the lung and spleen of mice. The particles were administered in three different doses (1, 10, and 100 mg QDs/kg of body weight) by intravenous injection into the caudal vein of Swiss mice. After 1, 6, 24, and 72 h, the animals were euthanized, and the lung and spleen tissues were harvested for the evaluation of antioxidant enzyme activity, lipid peroxidation, protein expression, and epigenetic and morphological changes. The obtained results highlighted a low toxicity in pulmonary and splenic tissues for concentrations up to 10 mg SiQDs/kg body, demonstrated by biochemical and histopathological analysis. Therefore, our study brings new experimental evidence on the biocompatibility of this type of QD, suggesting the possibility of expanding research on the biomedical applications of SiQDs.
Ecologically Modified Leather of Bacterial Origin
Authors: Lisowski Dawid , Bielecki Stanisław , Cichosz Stefan , Masek Anna
Published: June 2024

The research presented here is an attempt to develop an innovative and environmentally friendly material based on bacterial nanocellulose (BNC), which will be able to replace both animal skins and synthetic polymer products. Bacterial nanocellulose becomes stiff and brittle when dried, so attempts have been made to plasticise this material so that BNC can be used in industry. The research presented here focuses on the ecological modification of bacterial nanocellulose with vegetable oils such as rapeseed oil, linseed oil, and grape seed oil. The effect of compatibilisers of a natural origin on the plasticisation process of BNC, such as chlorophyll, curcumin, and L-glutamine, was also evaluated. BNC samples were modified with rapeseed, linseed, and grapeseed oils, as well as mixtures of each of these oils with the previously mentioned additives. The modification was carried out by passing the oil, or oil mixture, through the BNC using vacuum filtration, where the BNC acted as a filter. The following tests were performed to determine the effect of the modification on the BNC: FTIR spectroscopic analysis, contact angle measurements, and static mechanical analysis. As a result of the modification, the BNC was plasticised. Rapeseed oil proved to be the best for this purpose, with the help of which a material with good strength and elasticity was obtained.
Analysis of the Steelmaking Process via Data Mining and Pearson Correlation
Authors: Carrasco-López Susana , Herrera-Trejo Martín , Castro-Román Manuel , Castro-Uresti Fabián , Castro-Cedeño Edgar Iván
Published: June 2024

The continuous improvement of the steelmaking process is a critical issue for steelmakers. In the production of Ca-treated Al-killed steel, the Ca and S contents are controlled for successful inclusion modification treatment. In this study, a machine learning technique was used to build a decision tree classifier and thus identify the process variables that most influence the desired Ca and S contents at the end of ladle furnace refining. The attribute of the root node of the decision tree was correlated with process variables via the Pearson formalism. Thus, the attribute of the root node corresponded to the sulfur distribution coefficient at the end of the refining process, and its value allowed for the discrimination of satisfactory heats from unsatisfactory heats. The variables with higher correlation with the sulfur distribution coefficient were the content of sulfur in both steel and slag at the end of the refining process, as well as the Si content at that stage of the process. As secondary variables, the Si content and the basicity of the slag at the end of the refining process were correlated with the S content in the steel and slag, respectively, at that stage. The analysis showed that the conditions of steel and slag at the beginning of the refining process and the efficient S removal during the refining process are crucial for reaching desired Ca and S contents.
Robust Adaptive Fault-Tolerant Control of Quadrotor Unmanned Aerial Vehicles
Authors: Imran Imil Hamda , Alyazidi Nezar M. , Eltayeb Ahmed , Ahmed Gamil
Published: June 2024

The paper introduces a robust adaptive fault-tolerant control system for the six-degree-of-freedom (six-DOF) dynamics of quadrotor unmanned aerial vehicles (UAVs), incorporating disturbances and abrupt actuator faults to represent real-world conditions. The proposed control scheme employs robust control terms to manage unknown disturbances. However, robust control performance may degrade due to sudden fault impacts. To handle this issue, we introduce adaptive laws to ensure continuous adaptation. The control architecture ensures the tracking system’s stability by combining robust control using sliding-mode control (SMC) with adaptive control developed using the certainty equivalence principle. The sliding-surface error limits the adaptive laws, in which the convergence of estimated parameters to the actual unknown variables is not required as they fully rely on the convergence of the tracking error. We provide rigorous mathematics to validate the proposed control design. Furthermore, we conduct numerical simulations for a quadrotor UAV to showcase the effectiveness of the proposed scheme. The results demonstrate the efficacy of the proposed design in handling external disturbances and abrupt actuator faults.
Typology and Design of Parametric Cat-in-a-Box and Cat-in-a-Grid Triggers for Tropical Cyclone Risk Transfer
Authors: Franco Guillermo , Lemke-Verderame Laura , Guidotti Roberto , Yuan Ye , Bussi Gianbattista , Lohmann Dag , Bazzurro Paolo
Published: June 2024

The insurance industry has used parametric solutions to transfer catastrophe risks since the 1990s. Instead of relying on a lengthy process to assess a claim, these products pay the insured a pre-agreed amount if the physical characteristics of the event fulfill pre-defined conditions. Cat-in-a-box or cat-in-a-circle triggers, commonly used tools for tropical cyclone risk transfer, provide a payout to the insured if the track of a hurricane crosses the perimeter of a geographic area defined by a polygon or a circle with a certain intensity. Cat-in-a-grid solutions are novel and more sophisticated. They rely on a set of multiple cat-in-a-box triggers arranged on an orthogonal grid. The consideration of multiple geographic domains instead of a single box or circle is helpful to reduce basis risk, i.e., the difference between the parametric loss estimate and the target loss. In the case study for Miami presented here, for instance, a cat-in-a-grid solution showed 18.5% less basis risk than a typical cat-in-a-box alternative. To organize the different types of triggers within a common framework, we classify the existing alternatives based on whether they use a single geographic domain (like a box or a circle) or multiple domains (like a grid). We discuss their advantages and disadvantages and describe the process required to calibrate any one solution with the help of a catastrophe-risk model. We focus, in particular, on the analysis and construction of cat-in-a-grid triggers, the alternative that we believe offers the greatest potential for global standardization and adoption.
Flexible and Compact MLWE-Based KEM
Authors: Liang Wenqi , Liu Zhaoman , Zhao Xuyang , Yang Yafang , Liang Zhichuang
Published: June 2024

In order to resist the security risks caused by quantum computing, post-quantum cryptography (PQC) has been a research focus. Constructing a key encapsulation mechanism (KEM) based on lattices is one of the promising PQC routines. The algebraically structured learning with errors (LWE) problem over power-of-two cyclotomics has been one of the most widely used hardness assumptions for lattice-based cryptographic schemes. However, power-of-two cyclotomic rings may be exploited in the inflexibility of selecting parameters. Recently, trinomial cyclotomic rings of the form Zq[x]/(xn−xn/2+1), where n=2k3l, k≥1,l≥0, have received widespread attention due to their flexible parameter selection. In this paper, we propose Tyber, a variant scheme of the NIST-standardized KEM candidate Kyber over trinomial cyclotomic rings. We provide three parameter sets, aiming at the quantum security of 128, 192, and 256 bits (actually achieving 129, 197, and 276 bits) with matching and negligible error probabilities. When compared to Kyber, our Tyber exhibits stronger quantum security, by 22, 31, and 44 bits, than Kyber for three security levels.
Using the Assembly Time as a Tool to Control the Surface Morphology and Separation Performance of Membranes with a Tannic Acid–Fe3+ Selective Layer
Authors: Kinfu Hluf Hailu , Rahman Md. Mushfequr , Schneider Erik S. , Cevallos-Cueva Nicolás , Abetz Volker
Published: June 2024

Thin-film composite (TFC) membranes containing a metal–polyphenol network (MPN)-based selective layer were fabricated on a porous polyacrylonitrile support. The MPN layer was formed through coordination-based self-assembly between plant-based tannic acid (TA) and an Fe3+ ion. For the first time, we demonstrate that TFC membranes containing TA-Fe3+ selective layers can separate small organic solutes in aqueous media from equimolar mixtures of solutes. The effect of the assembly time on the characteristics and performance of the fabricated selective layer was investigated. An increase in the assembly time led to the formation of selective layers with smaller effective pore sizes. The tannic acid–Fe3+ selective layer exhibited a low rejection towards neutral solutes riboflavin and poly(ethylene glycol) while high rejections were observed for anionic dyes of orange II and naphthol green B. Permeation selectivities in the range of 2–27 were achieved between neutral and charged dyes in both single- and mixed-solute experiments, indicating the significant role of Donnan exclusion and the charge-selective nature of the membranes. The rejection efficiency improved with an increasing assembly time. Overall, this study demonstrates that the assembly time is a vital casting parameter for controlling the permeance, rejection and selectivity of thin-film composite membranes with a tannic acid–Fe3+ selective layer.
Alignment Control of Ferrite-Decorated Nanocarbon Material for 3D Printing
Authors: Boonhaijaroen Narit , Sitthi-amorn Pitchaya , Srituravanich Werayut , Suanpong Kwanrat , Ekgasit Sanong , Pengprecha Somchai
Published: June 2024

This paper demonstrates the potential of anisotropic 3D printing for alignable carbon nanomaterials. The ferrite-decorated nanocarbon material was synthesized via a sodium solvation process using epichlorohydrin as the coupling agent. Employing a one-pot synthesis approach, the novel material was incorporated into a 3D photopolymer, manipulated, and printed using a low-cost microscale 3D printer, equipped with digital micromirror lithography, monitoring optics, and magnetic actuators. This technique highlights the ability to control the microstructure of 3D-printed objects with sub-micron precision for applications such as microelectrode sensors and microrobot fabrication.