bluuebunny/crossref_metadata_2025 huggingface dataset:
Three-Dimensional Cell Cultures: The Bridge between In Vitro and In Vivo Models
Authors: Urzì Ornella , Gasparro Roberta , Costanzo Elisa , De Luca Angela , Giavaresi Gianluca , Fontana Simona , Alessandro Riccardo
Published: July 2023

Although historically, the traditional bidimensional in vitro cell system has been widely used in research, providing much fundamental information regarding cellular functions and signaling pathways as well as nuclear activities, the simplicity of this system does not fully reflect the heterogeneity and complexity of the in vivo systems. From this arises the need to use animals for experimental research and in vivo testing. Nevertheless, animal use in experimentation presents various aspects of complexity, such as ethical issues, which led Russell and Burch in 1959 to formulate the 3R (Replacement, Reduction, and Refinement) principle, underlying the urgent need to introduce non-animal-based methods in research. Considering this, three-dimensional (3D) models emerged in the scientific community as a bridge between in vitro and in vivo models, allowing for the achievement of cell differentiation and complexity while avoiding the use of animals in experimental research. The purpose of this review is to provide a general overview of the most common methods to establish 3D cell culture and to discuss their promising applications. Three-dimensional cell cultures have been employed as models to study both organ physiology and diseases; moreover, they represent a valuable tool for studying many aspects of cancer. Finally, the possibility of using 3D models for drug screening and regenerative medicine paves the way for the development of new therapeutic opportunities for many diseases.
Autophagy Inhibition via Hydroxychloroquine or 3-Methyladenine Enhances Chemotherapy-Induced Apoptosis in Neuro-Blastoma and Glioblastoma
Authors: Wear Darcy , Bhagirath Eesha , Balachandar Arpana , Vegh Caleb , Pandey Siyaram
Published: July 2023

Neuroblastoma is the most common tumour in children under 1 year old, accounting for 12–15% of childhood cancer deaths. Although current treatments are relatively efficacious against this cancer, associated adverse effects could be detrimental to growth and development. In contrast, glioblastoma accounts for 52% of brain tumours and has an extremely poor prognosis. Current chemotherapeutics include temozolomide, which has numerous negative side-effects and a low-effective rate. Previous studies have shown the manipulation of autophagy to be a promising method for targeting cancers, including glioblastoma. We sought to determine the effects of autophagic alterations in combination with current chemotherapies in both neuroblastoma and glioblastoma. Supplementing cisplatin or temozolomide with autophagy activator rapamycin stabilized cancer cell mitochondria, despite having little effect on apoptosis or oxidative stress. Autophagy inhibition via 3-methyladenine or hydroxychloroquine alongside standard chemotherapies enhanced apoptosis and oxidative stress, with 3-methyladenine also disrupting mitochondrial health. Importantly, combining hydroxychloroquine with 0.5 µM cisplatin or 50 µg/mL temozolomide was as or more effective than 2 µM cisplatin or 100 µg/mL temozolomide alone. Analyzing these interesting results, a combined treatment of autophagy inhibitor with a standard chemotherapeutic agent could help to improve patient prognosis and reduce chemotherapy doses and their associated side-effects.
SARS-CoV-2 Spike Protein Interaction Space
Authors: Lungu Claudiu N. , Putz Mihai V.
Published: July 2023

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a +sense single-strand RNA virus. The virus has four major surface proteins: spike (S), envelope (E), membrane (M), and nucleocapsid (N), respectively. The constitutive proteins present a high grade of symmetry. Identifying a binding site is difficult. The virion is approximately 50–200 nm in diameter. Angiotensin-converting enzyme 2 (ACE2) acts as the cell receptor for the virus. SARS-CoV-2 has an increased affinity to human ACE2 compared with the original SAR strain. Topological space, and its symmetry, is a critical component in molecular interactions. By exploring this space, a suitable ligand space can be characterized accordingly. A spike protein (S) computational model in a complex with ACE 2 was generated using silica methods. Topological spaces were probed using high computational throughput screening techniques to identify and characterize the topological space of both SARS and SARS-CoV-2 spike protein and its ligand space. In order to identify the symmetry clusters, computational analysis techniques, together with statistical analysis, were utilized. The computations are based on crystallographic protein data bank PDB-based models of constitutive proteins. Cartesian coordinates of component atoms and some cluster maps were generated and analyzed. Dihedral angles were used in order to compute a topological receptor space. This computational study uses a multimodal representation of spike protein interactions with some fragment proteins. The chemical space of the receptors (a dimensional volume) suggests the relevance of the receptor as a drug target. The spike protein S of SARS and SARS-CoV-2 is analyzed and compared. The results suggest a mirror symmetry of SARS and SARS-CoV-2 spike proteins. The results show thatSARS-CoV-2 space is variable and has a distinct topology. In conclusion, surface proteins grant virion variability and symmetry in interactions with a potential complementary target (protein, antibody, ligand). The mirror symmetry of dihedral angle clusters determines a high specificity of the receptor space.
Cryotherapy Attenuates Inflammation via the lncRNA SNHG1/miR-9-5p/NFKB1 Regulatory Axis in Periodontal Ligament Cells
Authors: Lin Can , Liu Miaomiao , Guo Jihua , Jia Rong
Published: July 2023

Cryotherapy is a common non-pharmacological method to relieve pain and inflammation. Clinical studies have shown that cryotherapy can reduce postoperative pain after root canal therapy, but the mechanism remains unclear. In this study, we aimed to investigate the underlying molecular mechanisms by which cryotherapy reduces inflammation in lipopolysaccharide (LPS)-stimulated periodontal ligament cells through transcriptome sequencing analysis. We found that cryotherapy significantly reduced the expression of multiple proinflammatory cytokines and chemokines, and NFKB1 was the key regulator down-regulated by cryotherapy. Importantly, we discovered that lncRNA SNHG1 expression level significantly decreased after cold treatment. SNHG1 expression was positively related to NFKB1 while negatively correlated with miR-9-5p, which formed a novel ceRNA regulatory pathway. Knockdown of SNHG1 significantly reduced the expression of NFKB1, IL1B, and IL6, while overexpression of SNHG1 significantly increased the expression of these genes. In conclusion, our study demonstrated that cryotherapy can effectively reduce inflammation in LPS-induced periodontal ligament cells by suppressing the lncRNA SNHG1/miR-9-5p/NFKB1 axis.
NMR-Chemical-Shift-Driven Protocol Reveals the Cofactor-Bound, Complete Structure of Dynamic Intermediates of the Catalytic Cycle of Oncogenic KRAS G12C Protein and the Significance of the Mg2+ Ion
Authors: Gadanecz Márton , Fazekas Zsolt , Pálfy Gyula , Karancsiné Menyhárd Dóra , Perczel András
Published: July 2023

In this work, catalytically significant states of the oncogenic G12C variant of KRAS, those of Mg2+-free and Mg2+-bound GDP-loaded forms, have been determined using CS-Rosetta software and NMR-data-driven molecular dynamics simulations. There are several Mg2+-bound G12C KRAS/GDP structures deposited in the Protein Data Bank (PDB), so this system was used as a reference, while the structure of the Mg2+-free but GDP-bound state of the RAS cycle has not been determined previously. Due to the high flexibility of the Switch-I and Switch-II regions, which also happen to be the catalytically most significant segments, only chemical shift information could be collected for the most important regions of both systems. CS-Rosetta was used to derive an “NMR ensemble” based on the measured chemical shifts, which, however, did not contain the nonprotein components of the complex. We developed a torsional restraint set for backbone torsions based on the CS-Rosetta ensembles for MD simulations, overriding the force-field-based parametrization in the presence of the reinserted cofactors. This protocol (csdMD) resulted in complete models for both systems that also retained the structural features and heterogeneity defined by the measured chemical shifts and allowed a detailed comparison of the Mg2+-bound and Mg2+-free states of G12C KRAS/GDP.
Differential Responses of Retinal Neurons and Glia Revealed via Proteomic Analysis on Primary and Secondary Retinal Ganglion Cell Degeneration
Authors: Kwong Jacky M. K. , Caprioli Joseph , Lee Joanne C. Y. , Song Yifan , Yu Feng-Juan , Bian Jingfang , Sze Ying-Hon , Li King-Kit , Do Chi-Wai , To Chi-Ho , Lam Thomas Chuen
Published: July 2023

To explore the temporal profile of retinal proteomes specific to primary and secondary retinal ganglion cell (RGC) loss. Unilateral partial optic nerve transection (pONT) was performed on the temporal side of the rat optic nerve. Temporal and nasal retinal samples were collected at 1, 4 and 8 weeks after pONT (n = 4 each) for non-biased profiling with a high-resolution hybrid quadrupole time-of-flight mass spectrometry running on label-free SWATHTM acquisition (SCIEX). An information-dependent acquisition ion library was generated using ProteinPilot 5.0 and OneOmics cloud bioinformatics. Combined proteome analysis detected 2531 proteins with a false discovery rate of <1%. Compared to the nasal retina, 10, 25 and 61 significantly regulated proteins were found in the temporal retina at 1, 4, and 8 weeks, respectively (p < 0.05, FC ≥ 1.4 or ≤0.7). Eight proteins (ALDH1A1, TRY10, GFAP, HBB-B1, ALB, CDC42, SNCG, NEFL) were differentially expressed for at least two time points. The expressions of ALDH1A1 and SNCG at nerve fibers were decreased along with axonal loss. Increased ALDH1A1 localization in the inner nuclear layer suggested stress response. Increased GFAP expression demonstrated regional reactivity of astrocytes and Muller cells. Meta-analysis of gene ontology showed a pronounced difference in endopeptidase and peptidase inhibitor activity. Temporal proteomic profiling demonstrates established and novel protein targets associated with RGC damage.
Alberta Spinal Muscular Atrophy Newborn Screening—Results from Year 1 Pilot Project
Authors: Niri Farshad , Nicholls Jessie , Baptista Wyatt Kelly , Walker Christine , Price Tiffany , Kelln Rhonda , Hume Stacey , Parboosingh Jillian , Lilley Margaret , Kolski Hanna , Ridsdale Ross , Muranyi Andrew , Mah Jean K. , Bulman Dennis E.
Published: July 2023

Spinal muscular atrophy (SMA) is a progressive neuromuscular disease caused by biallelic pathogenic/likely pathogenic variants of the survival motor neuron 1 (SMN1) gene. Early diagnosis via newborn screening (NBS) and pre-symptomatic treatment are essential to optimize health outcomes for affected individuals. We developed a multiplex quantitative polymerase chain reaction (qPCR) assay using dried blood spot (DBS) samples for the detection of homozygous absence of exon 7 of the SMN1 gene. Newborns who screened positive were seen urgently for clinical evaluation. Confirmatory testing by multiplex ligation-dependent probe amplification (MLPA) revealed SMN1 and SMN2 gene copy numbers. Six newborns had abnormal screen results among 47,005 newborns screened during the first year and five were subsequently confirmed to have SMA. Four of the infants received SMN1 gene replacement therapy under 30 days of age. One infant received an SMN2 splicing modulator due to high maternally transferred AAV9 neutralizing antibodies (NAb), followed by gene therapy at 3 months of age when the NAb returned negative in the infant. Early data show that all five infants made excellent developmental progress. Based on one year of data, the incidence of SMA in Alberta was estimated to be 1 per 9401 live births.
A Tutorial on Agricultural IoT: Fundamental Concepts, Architectures, Routing, and Optimization
Authors: Effah Emmanuel , Thiare Ousmane , Wyglinski Alexander M.
Published: July 2023

This paper presents an in-depth contextualized tutorial on Agricultural IoT (Agri-IoT), covering the fundamental concepts, assessment of routing architectures and protocols, and performance optimization techniques via a systematic survey and synthesis of the related literature. The negative impacts of climate change and the increasing global population on food security and unemployment threats have motivated the adoption of the wireless sensor network (WSN)-based Agri-IoT as an indispensable underlying technology in precision agriculture and greenhouses to improve food production capacities and quality. However, most related Agri-IoT testbed solutions have failed to achieve their performance expectations due to the lack of an in-depth and contextualized reference tutorial that provides a holistic overview of communication technologies, routing architectures, and performance optimization modalities based on users’ expectations. Thus, although IoT applications are founded on a common idea, each use case (e.g., Agri-IoT) varies based on the specific performance and user expectations as well as technological, architectural, and deployment requirements. Likewise, the agricultural setting is a unique and hostile area where conventional IoT technologies do not apply, hence the need for this tutorial. Consequently, this tutorial addresses these via the following contributions: (1) a systematic overview of the fundamental concepts, technologies, and architectural standards of WSN-based Agri-IoT, (2) an evaluation of the technical design requirements of a robust, location-independent, and affordable Agri-IoT, (3) a comprehensive survey of the benchmarking fault-tolerance techniques, communication standards, routing and medium access control (MAC) protocols, and WSN-based Agri-IoT testbed solutions, and (4) an in-depth case study on how to design a self-healing, energy-efficient, affordable, adaptive, stable, autonomous, and cluster-based WSN-specific Agri-IoT from a proposed taxonomy of multi-objective optimization (MOO) metrics that can guarantee an optimized network performance. Furthermore, this tutorial established new taxonomies of faults, architectural layers, and MOO metrics for cluster-based Agri-IoT (CA-IoT) networks and a three-tier objective framework with remedial measures for designing an efficient associated supervisory protocol for cluster-based Agri-IoT networks.
Effect of Telerehabilitation and Outpatient Rehabilitation in Women with Breast Cancer
Authors: Scaturro Dalila , Vitagliani Fabio , Mangano Maria Silvia , Tomasello Sofia , Sconza Cristiano , Respizzi Stefano , Vecchio Michele , Letizia Mauro Giulia
Published: July 2023

Telemedicine was shown to be indispensable during the SARS-CoV-2 pandemic to ensure continuity of care for fragile patients. We compared a telerehabilitation program versus an outpatient rehabilitation program in women with breast cancer undergoing quadrantectomy surgery. There were 56 women with breast cancer divided into two groups: the treatment group (TG), made up of 24 patients undergoing a remote rehabilitation project program; and the control group (CG), composed of 32 patients subjected to the same rehabilitation project program in an outpatient setting. At the time of enrollment (T0) and the end of the 8 weeks of treatment (T1), the following questionnaire scores were considered: numerical rating scale (NRS), Disabilities of the Arm, Shoulder and Hand questionnaire (Quick-DASH), Piper fatigue scale (PFS)m and Breast Cancer Therapy Functional Rating Scale (FACT-B). We observed that the CG showed greater improvements than the TG in upper limb function (7.8 ± 4.2 vs. 10.9 ± 4.9; p < 0.05) and quality of life (27.9 ± 7.2 vs. 40.0 ± 3.3; p < 0.05). No difference in efficacy between the two groups was observed for pain (2.2 ± 0.6 vs. 2.3 ± 0.9; p = 0.64) and fatigue (3.2 ± 1.1 vs. 3.2 ± 0.6; p = 0.66). Telerehabilitation is a valid tool in the management of women with breast cancer in the postoperative phase. However, face-to-face rehabilitation treatment may be preferred because it is more effective as it allows the construction of a specific, personalized, and targeted rehabilitation program.
Visual Search Strategies of Elite Fencers: An Exploratory Study in Ecological Competitive Situation
Authors: Bagot Pierre , Fournier Jean F. , Kerivel Thibault , Bossard Cyril , Kermarrec Gilles , Martinent Guillaume , Bernier Marjorie
Published: July 2023

This study investigates the visual activity of fencers in conditions resembling official competitions. Previous research in experimental conditions has shown that experts focus on specific areas of the torso and the armed arm to control movement initiation. Eight right-handed fencers (epee: two males, one female; foil: one male; sabre: two males, two females) participated in a simulated competition, wearing an eye tracker during one bout. The findings showed that the main fixation in foil and sabre is the upper torso, while in epee, it is the lower torso. In epee and sabre, the upper torso is viewed about 50% of the time, with three other areas also observed, while in foil, the fixation is totally directed to the upper torso. Additionally, two new areas of interest were identified: the score machine and an area involving fixations other than the opponent. The study found no direct link between visual activity and performance. The visual search strategy varies among weapons, with foil using a gaze anchor or foveal spot and epee and sabre utilizing a visual pivot due to the discipline’s inherent rules. The study also emphasizes that competition-like conditions can disrupt visual activity with external stimuli, possibly affecting performance.
Clitic Placement and the Grammaticalization of the Future and the Conditional in Old Catalan
Authors: Torres-Latorre Aina , Sentí Andreu
Published: July 2023

The romance future and conditional tenses are the result of the grammaticalization of Latin periphrasis, mainly cantāre habeō. In some medieval Romance languages, including Catalan, two types of forms existed: synthetic forms (faré ‘I will do’) and analytical forms (fer-lo he ‘I will do it’). Analytical forms do not present univerbation and are thus less grammaticalized than synthetic forms. The present work aims to study the distribution of synthetic and analytical forms diachronically. A diachronic corpus (11th c.–16th c.) was compiled to serve this purpose. According to the syntactic restrictions of clitic placement, analytical forms could appear in the same syntactic environments than synthetic forms with postverbal pronouns (faré-lo ‘I will do it’). Therefore, only those contexts are analysed to assess the degree of grammaticalization. Some recent works point out that the grammaticalization of future and conditional was more advanced in the eastern languages of the Iberian Peninsula, such as Catalan, than in the western ones. The results from our corpus confirm these differences. In addition, the data show another grammaticalization process: the evolution of clitic placement towards a fixed preverbal position.
Complete Mitogenome Sequencing, Annotation, and Phylogeny of Grateloupia turuturu, a Red Alga with Intronic cox1 Gene
Authors: Patil Maheshkumar Prakash , Kim Jong-Oh , Kim Young-Ryun , Yoon Seokjin , Kim Kyunghoi
Published: July 2023

The mitochondrial genome (mitogenome) is essential for identifying species and tracing genetic variation, gene patterns, and evolutionary studies. Here, the mitogenome of Grateloupia turuturu was sequenced on the Illumina sequencing platform. This circular mitogenome (28,265 bp) contains 49 genes, including three rRNAs, twenty transfer RNAs (tRNAs), and twenty-six protein-coding genes (PCGs). Nucleotide composition indicates biased AT (68.8%) content. A Group II intronic sequence was identified between two exons of the cox1 gene, and this sequence comprises an open reading frame (ORF) that encodes a hypothetical protein. The gene content, annotation, and genetic makeup are identical to those of Halymeniaceae members. The complete mitogenome sequences of the Grateloupia and Polyopes species were used in a phylogenetic analysis, which revealed that these two genera are monophyletic and that G. turuturu and G. elliptica are closely related. This newly constructed mitogenome will help us better understand the general trends in the development of cox1 introns in Halymeniaceae, as well as the evolution of red algal mitogenomes within the Rhodophyta and among diverse algal species.
Genomic Surveillance of SARS-CoV-2 in Malaysia during the Era of Endemic COVID-19
Authors: Lee Tze Yan , Lim Wai Feng , Ang Geik Yong , Yu Choo Yee
Published: July 2023

On 5 May 2023, WHO declared the end of coronavirus disease 2019 (COVID-19) as a public health emergency of international concern. However, the risk of new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants causing rapid and high surges in cases and deaths remained. In Malaysia, five COVID-19 waves during the pandemic phase were well characterized, but similar studies focusing on the endemic phase were lacking. Hence, we retrieved 14,965 SARS-CoV-2 genomic sequences from the GISAID EpiCoV database for clade, lineage, and phylogenetic analysis in order to provide an insight into the population dynamics of SARS-CoV-2 that circulated in Malaysia from June 2022 to April 2023. The dominance of the Omicron variants was observed, and two new waves of infections driven by BA.5.2 and XBB.1, respectively, were detected. Data as of April 2023 also pointed to a possible eighth wave driven by XBB.1.9. Although new variants associated with higher transmissibility were behind the multiple surges, these subsequent waves had lower intensities as compared to the fourth and fifth waves. The on-going circulation and evolution of SARS-CoV-2 mean that COVID-19 still poses a serious threat, necessitating active genomic surveillance for early warning of potential new variants of concern.
Blast Resistance Capacities of Structural Panels Subjected to Shock-Tube Testing with ANFO Explosive
Authors: Park Gang-Kyu , Moon Jae Heum , Shin Hyun-Seop , Kim Sung-Wook
Published: July 2023

This study presents a series of shock-tube tests conducted on structural panels using ammonium nitrate fuel oil (ANFO) as the explosive. The characteristics of the blast waves propagating through the shock tube were analyzed by measuring the pressure generated at specific locations inside the shock tube. The extent of differences in blast pressure generated in a confined space, such as the shock tube, was compared to that predicted by the proposed method in the Unified Facilities Criteria 3-340-02 report. The target specimens of this study were plain reinforced concrete (RC), high-performance fiber-reinforced cementitious composites (HPFRCCs), and composite panels. Polyurea-coated RC panels and steel plate grid structure-attached RC panels were used as composite panels to evaluate the effectiveness of the coating and structural damping methods on the enhancement of structural blast resistance. The tests were conducted with different ANFO charges, and the crack patterns and lengths on the rear surface of each panel were measured. Based on the measured results, discussions regarding the blast resistance capacities of each panel type are provided.
Mechanical Properties of Composite Silty Soil Modified with Cement and Zirconia-Based Nanopowder
Authors: Hu Jun , Xu Chenming , Ren Junhao , Xiong Hui , Wang Zhixin , Yang Yongchang
Published: July 2023

This study assessed the modification effects of zirconia-based nanopowder and cement contents and curing age on the mechanical properties of silty soil. The orthogonal test design was applied to derive the best combination of each influencing factor using the lateral unconfined compressive test. Two-dimensional particle flow code (PFC2D) distinct-element modeling software was also used to fit and analyze the test curves, as well as simulate the triaxial test with the derived parameters. The test results reveal the optimal combination of 20% cement, 2% zirconia-based nanopowder, and 28 d curing age. The extreme difference table was used to plot the orthogonal trend diagram, and cement content was found to be the most significant factor controlling the silty soil strength. The maximum peak stress was 2196.33 kPa under the optimum combination of factors, which could be obtained through the index estimation, and these results were experimentally verified. According to the predicted strength envelope, the cohesive force of nanopowder-cement-modified silty soil in the optimal proportion was 717.11 kPa, and the internal friction angle was 21.05°. Nano zirconium dioxide will accelerate the hydration reaction of cement, the flocculent structure produced by the hydration of cement and soil particles connected to each other, play the role of filling and anchoring, and thus increase the strength of the nano-zirconium dioxide, and the optimal dosage of nano-zirconium dioxide is 2%.
Methodology for Evaluating the CO2 Sequestration Capacity of Waste Ashes
Authors: Tominc Sara , Ducman Vilma
Published: July 2023

The concentration of CO2 in the atmosphere is constantly increasing, leading to an increase in the average global temperature and, thus, affecting climate change. Hence, various initiatives have been proposed to mitigate this process, among which CO2 sequestration is a technically simple and efficient approach. The spontaneous carbonation of ashes with atmospheric CO2 is very slow, and this is why accelerated carbonation is encouraged. However, not all ashes are equally suitable for this process, so a methodology to evaluate their potential should be developed. Such a methodology involves a combination of techniques, from theoretical calculations to XRF, XRD, DTA-TG, and the calcimetric determination of the CaCO3 content. The present study followed the approach of exposing ashes to accelerated carbonation conditions (4% v/v CO2, 50–55% and 80–85% RH, 20 °C) in a closed carbonation chamber for different periods of time until the maximum CO2 uptake is reached. The amount of sequestered CO2 was quantified by thermogravimetry. The results show that the highest CO2 sequestration capacity (33.8%) and carbonation efficiency (67.9%) were obtained for wood biomass bottom ash. This method was applied to eight combustion ashes and could serve to evaluate other ashes or comparable carbon storage materials.
Research on the Dynamic Characteristics of Perfluoroalkoxy Alkane Springs
Authors: Ni Jing , Feng Yujie , Cui Zhi , He Lihua , Sun Jingbo
Published: July 2023

Semiconductor cleaning system ultra-clean flow control pumps are critical equipment in the semiconductor industry. Among them, the perfluoroalkoxy alkane (PFA) spring is a pivotal component to control the pump, and its dynamic performance is crucial to ensure the efficient operation of the system. However, the dynamic performance of the spring is often affected by the operating frequency. This paper studied the effect of different working frequencies on the dynamic property of the spring through compression-cycle experiments under uniaxial sinusoidal excitation. The force–displacement curves under different compression frequencies were fitted to obtain the dynamic stiffness of the PFA spring under different cyclic loading frequencies. The variation in the spring’s hysteresis coefficient was evaluated using the hysteresis curves of different cyclic loading conditions. After 2 million compression experiments, the changes in dynamic stiffness, hysteresis coefficient, and spring height were investigated. The obtained results revealed that, as the frequency increases, the dynamic stiffness of the spring increases. The hysteresis coefficient of the PFA spring is the largest at 10 Hz and the smallest at 6 Hz. Upon conducting 2 million compression tests, it was discovered that the dynamic stiffness experiences the greatest attenuation rate of 4.19% at a frequency of 8 Hz, whereas the hysteresis coefficient undergoes the largest attenuation of 42.1% at a frequency of 6 Hz. The results will help to improve the design and application level of PFA springs.
Surface Defect Detection for Automated Tape Laying and Winding Based on Improved YOLOv5
Authors: Wen Liwei , Li Shihao , Ren Jiajun
Published: July 2023

To address the issues of low detection accuracy, slow detection speed, high missed detection rate, and high false detection rate in the detection of surface defects on pre-impregnated composite materials during the automated tape laying and winding process, an improved YOLOv5 (You Only Look Once version 5) algorithm model was proposed to achieve the high-precision, real-time detection of surface defects. By leveraging this improvement, the necessity for frequent manual interventions, inspection interventions, and subsequent rework during the automated lay-up process of composite materials can be significantly reduced. Firstly, to improve the detection accuracy, an attention mechanism called “CA (coordinate attention)” was introduced to enhance the feature extraction ability, and a Separate CA structure was used to improve the detection speed. Secondly, we used an improved loss function “SIoU (SCYLLA-Intersection over Union) loss” to replace the original “CIoU (Complete-Intersection over Union) loss”, which introduced an angle loss as a penalty term to consider the directional factor and improve the stability of the target box regression. Finally, Soft-SIoU-NMS was used to replace the original NMS (non-maximum suppression) of YOLOv5 to improve the detection of overlapping defects. The results showed that the improved model had a good detection performance for surface defects on pre-impregnated composite materials during the automated tape laying and winding process. The FPS (frames per second) increased from 66.7 to 72.1, and the mAP (mean average precision) of the test set increased from 92.6% to 97.2%. These improvements ensured that the detection accuracy, as measured by the mAP, surpassed 95%, while maintaining a detection speed of over 70 FPS, thereby meeting the requirements for real-time online detection.
Catalysis of a Diels–Alder Reaction between Azachalcones and Cyclopentadiene by a Recyclable Copper(II)-PEIP Metal-Organic Framework
Authors: Hadjikyprianou Eleni , Petrides Sotiris , Kourtellaris Andreas , Tasiopoulos Anastasios J. , Georgiades Savvas N.
Published: July 2023

Metal-organic frameworks (MOFs) have attracted considerable interest as emerging heterogeneous catalysts for organic transformations of synthetic utility. Herein, a Lewis-acidic MOF, {[Cu3(PEIP)2(5-NH2-mBDC)(DMF)]·7DMF}∞, denoted as Cu(ΙΙ)-PEIP, has been synthesized via a one-pot process and deployed as an efficient heterogeneous catalyst for a Diels–Alder cycloaddition. Specifically, the [4 + 2] cycloaddition of 13 substituted azachalcone dienophiles with cyclopentadiene has been investigated. MOF-catalyzed reaction conditions were optimized, leading to the selection of water as the solvent, in the presence of 10% mol sodium dodecyl sulfate (SDS) to address substrate solubility. The Cu(II)-PEIP catalyst showed excellent activity under these green and mild conditions, exhibiting comparable or, in some cases, superior efficiency to a homogeneous catalyst often employed in Diels–Alder reactions, namely, Cu(OTf)2. The nature of the azachalcone substituent played a significant role in the reactivity of the dienophiles, with electron-withdrawing (EW) substituents enhancing conversion and electron-donating (ED) ones exhibiting the opposite effect. Coordinating substituents appeared to enhance the endo selectivity. Importantly, the Cu(II)-PEIP catalyst can be readily isolated from the reaction mixture and recycled up to four times without any significant reduction in conversion or selectivity.
Research on Solid Shell Growth during Continuous Steel Casting
Authors: Velička Marek , Pyszko René , Machů Mario , Burda Jiří , Kubín Tomáš , Ovčačíková Hana , Rigo David
Published: July 2023

The continuous steel casting process must simultaneously meet the requirements for production performance, quality and safety against breakouts. Knowing the thickness of the solidified shell, particularly at the exit of the mould, is useful for the casting process control and breakout prevention. Shell thickness is difficult to measure during casting; in practice, it is predicted by indirect methods and models. But after undesired rupture of the shell and leakage of the liquid steel, it is possible to measure the shell thickness directly. This article is focused on the problem of the growth and measurement of the solid shell obtained after the breakout of a round block with a diameter of 410 mm. An original methodology was developed in which a surface mesh of points was created from the individual scanned parts of the block using a 3D laser scanner. Research has shown differences of up to 6 mm between the maximum and minimum shell thickness at the mould exit. A regression function of the average shell thickness on time was found. The results of the real shell growth were further used for the verification of the original numerical model of cooling and solidification of the round block.
Strengthening Mechanisms and Retention Properties of Sintered Iron-Based Matrix Material for Metallic-Diamond Tools
Authors: Cygan-Bączek Elżbieta , Romański Andrzej
Published: July 2023

This work presents the analysis of mechanisms controlling the deformation strengthening of the surface during abrasion and their impact on structural changes and mechanical properties of Fe-Mn-Cu-Sn-C matrix material, which was prepared by means of powder metallurgy (PM). The powder mixture was ball-milled for 8 h and densified to <1% porosity using hot pressing at 900 °C and 35 MPa. Phases and structural transformations taking place in austenite during plastic deformation were identified. The participation, distribution, and morphology of the phases, as well as the physicomechanical properties of the matrix material, were tested. It has been shown that during grinding, deformation twins are generated in areas where an austenitic microstructure is present. To test the ability of the matrix to keep diamond crystals firmly cylindrical (Ø11.3 mm× 5 mm), diamond-impregnated specimens containing diamond grits of 30/40 mesh in size and at a concentration of 20 (5% vol.) were prepared. It was finally determined by the diamond-retention index, which is the number of retained diamond particles compared to the total number of diamond particles and the pullouts on the working surface of the segment. This research shows that materials containing Ti- and Si-coated diamond particles, deposited by the CVD method, have the highest abrasion resistance and, therefore, have the best retention properties. In order to determine the bonding mechanism at the matrix–diamond interface, specimens were also analyzed by SEM and TEM.
Hybrid Artificial Neural Network-Based Models to Investigate Deformation Behavior of AZ31B Magnesium Alloy at Warm Tensile Deformation
Authors: Murugesan Mohanraj , Yu Jae-Hyeong , Chung Wanjin , Lee Chang-Whan
Published: July 2023

The uniaxial warm tensile experiments were carried out in deformation temperatures (50–250 °C) and strain rates (0.005 to 0.0167 s−1) to investigate the material workability and to predict flow stress of AZ31B magnesium alloy. The back–propagation artificial neural network (BP–ANN) model, a hybrid models with a genetic algorithm (GABP–ANN), and a constrained nonlinear function (CFBP–ANN) were investigated. In order to train the exploited machine learning models, the process parameters such as strain, strain rate, and temperature were accounted as inputs and flow stress was considered as output; moreover, the experimental flow stress values were also normalized to constructively run the neural networks and to achieve better generalization and stabilization in the trained network. Additionally, the proposed model’s closeness and validness were quantified by coefficient of determination (R2), relative mean square error (RMSE), and average absolute relative error (AARE) metrics. The computed statistical outcomes disclose that the flow stress predicted by both GABP–ANN and CFBP–ANN models exhibited better closeness with the experimental data. Moreover, compared with the GABP–ANN model outcomes, the CFBP–ANN model has a relatively higher predictability. Thus, the outcomes confirm that the proposed CFBP–ANN model can result in the accurate description of AZ31 magnesium alloy deformation behavior, showing potential for the purpose of practicing finite element analysis.
Magnetic Domains and Their Power Spectral Densities in Non-Oriented Electrical Steel after Thermal Compression at Different Rates
Authors: Wang Yuqi , Gao Zhenyu , Luo Li , Chen Chunmei , Zhao Zhiyang , Song Renbo , Zhang Yingchao
Published: July 2023

The magnetic domains of non-oriented electrical steel bearing cumulative thermal compressions made by a Gleeble 3500 Thermal System were observed using an atomic force microscope (AFM). The component forces, comprising the magnetic forces between the AFM probe and magnetic domains of the samples, along the freedom direction of the probe, were measured, and they formed the value fluctuation of the magnetic domains. The fluctuations of the magnetic domains were analyzed by examining the power spectral density (PSD) curves. The hysteresis curves of the samples were measured using a highly sensitive magnetic measurement system. An analysis of the magnetic force microscope (MFM) maps suggested that some magnetic domains were compressed into crushed and fragmented shapes, similar to the microstructure of deformed grains. Meanwhile, some were reconstructed within the thermal compressions, like dynamic recrystallization microstructures. Meaningfully, the MFM probe moved and deformed the proximal magnetic domains of tested samples within the region of its weak magnetic field. The peak positions of the magnetic domains with a high deformation rate were shifted and moved during the measuring processes by the weakly polarized probe. Both windward and leeward sides simultaneously expressed a slope towards each co-adjacent valley in the MFM maps and induced a statistical throbbing within a narrow band in the PSD curves. Thus, the MFM scanning mode was also analyzed and improved to obtain accurate MFM maps with low disturbances from the weak magnetic field of the probe. Swapping the order positions of the middle processes in the MFM scanning and adding a gliding step between them could offset the peak skewing of magnetic domains caused by the weakly polarized probe during MFM measurement process without incurring excessive replacement costs. Accumulative compression at a high rate (10 s−1) would crush magnetic domains into irregularly decreasing sizes with messy boundaries. This investigation provides an example of the complete relationships among deformations, magnetic domains, and magnetic properties.
Research on Cartilage 3D Printing Technology Based on SA-GA-HA
Authors: Chen Yong , Gong Youping , Shan Lijun , Tan Chou Yong , Al-Furjan MS , Ramesh S. , Chen Huipeng , Bian Xiangjuan , Chen Yanda , Liu Yunfeng , Zhou Rougang
Published: July 2023

Cartilage damage is difficult to heal and poses a serious problem to human health as it can lead to osteoarthritis. In this work, we explore the application of biological 3D printing to manufacture new cartilage scaffolds to promote cartilage regeneration. The hydrogel made by mixing sodium alginate (SA) and gelatin (GA) has high biocompatibility, but its mechanical properties are poor. The addition of hydroxyapatite (HA) can enhance its mechanical properties. In this paper, the preparation scheme of the SA-GA-HA composite hydrogel cartilage scaffold was explored, the scaffolds prepared with different concentrations were compared, and better formulations were obtained for printing and testing. Mathematical modeling of the printing process of the bracket, simulation analysis of the printing process based on the mathematical model, and adjustment of actual printing parameters based on the results of the simulation were performed. The cartilage scaffold, which was printed using Bioplotter 3D printer, exhibited useful mechanical properties suitable for practical needs. In addition, ATDC-5 cells were seeded on the cartilage scaffolds and the cell survival rate was found to be higher after one week. The findings demonstrated that the fabricated chondrocyte scaffolds had better mechanical properties and biocompatibility, providing a new scaffold strategy for cartilage tissue regeneration.
Developing Innovative Cement Composites Containing Vine Shoot Waste and Superplasticizers
Authors: Scurtu Daniela Alexandra , David Leontin , Levei Erika Andrea , Simedru Dorina , Filip Xenia , Roman Cecilia , Cadar Oana
Published: July 2023

The expansion of the construction industry requires large quantities of construction materials; therefore, the utilization of alternative raw materials that reduce the environmental impact and enhance the quality of the construction materials has received increasing interest. The comparative performance of 1% Dynamon SR3 or Dynamon SR41 superplasticizers on the properties of cement paste with 1 wt.% vine shoot waste addition (VSW) was investigated after 28 days using Fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), and solid-state 27Al and 29Si nuclear magnetic resonance (NMR) spectroscopy. VSW does not delay the formation of calcium hydroxide and C–S–H and a slight decrease of the –OH band in samples containing superplasticizers, suggesting that free lime is converted to carbonates. The highest degree of crystallinity was remarked for the samples with superplasticizers. The structure of the cement paste with VSW and superplasticizers was corroborated with mechanical properties, showing increased strength in using VSW and superplasticizers. The results showed that adding 1% VSW and superplasticizers does not change the performance of the cement paste but reduces the water-cement ratio. The combination of VSW and superplasticizers led to cement composite with improved structural and mechanical properties suitable for construction.
The Effect of Synbiotic Supplementation on Uremic Toxins, Oxidative Stress, and Inflammation in Hemodialysis Patients—Results of an Uncontrolled Prospective Single-Arm Study
Authors: Kuskunov Teodor , Tilkiyan Eduard , Doykov Daniel , Boyanov Krasimir , Bivolarska Anelia , Hristov Bozhidar
Published: July 2023

Introduction: Numerous studies to date have shown that the development of dysbiotic gut microbiota is a characteristic finding in chronic kidney disease (CKD). A number of uremic toxins progressively accumulate in the course of CKD, some of them generated by the intestinal microbiome, such as indoxyl sulfate (IS) and p-cresyl sulfate (p-CS). They are found to be involved in the pathogenesis of certain complications of uremic syndrome, including low-grade chronic inflammation and oxidative stress. The aim of the present study is to research the serum concentration of IS and p-CS in end stage renal disease (ESRD) patients undergoing conventional hemodialysis, as well as to study the possibilities of influencing some markers of inflammation and oxidative stress after taking a synbiotic. Materials and Methods: Thirty patients with end-stage renal disease (ESRD) undergoing hemodialysis treatment who were taking a synbiotic in the form of Lactobacillus acidophilus La-14 2 × 1011 (CFU)/g and prebiotic fructooligosaccharides were included in the study. Serum levels of total IS, total p-CS, Interleukin-6 (IL-6), and Malondialdehyde (MDA) were measured at baseline and after 8 weeks. Results. The baseline values of the four investigated indicators in the patients were significantly higher—p-CS (29.26 ± 58.32 pg/mL), IS (212.89 ± 208.59 ng/mL), IL-6 (13.84 ± 2.02 pg/mL), and MDA (1430.33 ± 583.42 pg/mL), compared to the results obtained after 8 weeks of intake, as we found a significant decrease in the parameters compared to the baseline—p-CS (6.40 ± 0.79 pg/mL, p = 0.041), IS (47.08 ± 3.24 ng/mL, p < 0.001), IL-6 (9.14 ± 1.67 pg/mL, p < 0.001), and MDA (1003.47 ± 518.37 pg/mL, p < 0.001). Conclusions: The current study found that the restoration of the intestinal microbiota in patients with CKD significantly decreases the level of certain uremic toxins. It is likely that this favorably affects certain aspects of CKD, such as persistent low-grade inflammation and oxidative stress.
Extraction and Modification of Cellulose Microfibers Derived from Biomass of the Amazon Ochroma pyramidale Fruit
Authors: Rocha Ana Luisa Farias , Feitosa Bianca de Andrade , Carolino Adriano de Souza , Nunes Ronald Zico de Aguiar , Macalia Célio Matias Airone , da Silva Kalil Araújo , Dias Cleverton Oliveira , de Souza Sérgio Michielon , Campelo Pedro Henrique , Bezerra Jaqueline de Araújo , Sanches Edgar Aparecido
Published: July 2023

Microfibers are important to several areas of human lifestyle, and the knowledge about their physicochemical characteristics allows for proposing new technological applications. The in natura microfiber of Ochroma pyramidale fruit (IN sample) and its extracted pulp (PU sample) were evaluated by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and Thermogravimetry and Differential Scanning Calorimetry (TG/dTG and DSC). Microfibers were composed mainly of (68 ± 1)% holocellulose, (35.8 ± 0.1)% cellulose, (32 ± 3)% lignin and (3.7 ± 0.3)% extractives. The XRD pattern of the PU sample revealed that the mercerization process resulted in the change of the cellulose crystal structure from Iα type (triclinic) to type II (monoclinic). The SEM technique showed that the IN sample presented regular cylindrical/hollow-shaped wire-like microfibers with diameters ranging from 5 µm to 25 µm. However, the mercerization process changed their natural morphology. A significant change in the FTIR spectra after the removal of hemicellulose and lignin components was observed: weak bands at 1739 cm−1 (C=O stretching of lignin and hemicellulose fractions), 1463 cm−1 (CH3 of lignin) and 1246 cm−1 (C-O of lignin) were still observed in the PU sample, indicating that the lignin was not completely removed due to the natural difficulty of isolating pure cellulose. The TG/dTG and DSC evaluation revealed a temperature increase of the second thermal event (starting at 235 °C) in the PU sample, which was assigned to the cellulose and residual hemicellulose degradation. Then, this work aimed to disseminate and characterize a microfiber with unusual characteristics still little explored by the scientific community, as well as its cellulosic pulp, providing information that may be useful in its application in different industries, enabling the positive development of new biocompatible, renewable and sustainable materials.