bluuebunny/crossref_metadata_2025 huggingface dataset:
What Are the Functional Roles of Piwi Proteins and piRNAs in Insects?
Authors: Santos Dulce , Feng Min , Kolliopoulou Anna , Taning Clauvis N. T. , Sun Jingchen , Swevers Luc
Published: February 2023

Research on Piwi proteins and piRNAs in insects has focused on three experimental models: oogenesis and spermatogenesis in Drosophila melanogaster, the antiviral response in Aedes mosquitoes and the molecular analysis of primary and secondary piRNA biogenesis in Bombyx mori-derived BmN4 cells. Significant unique and complementary information has been acquired and has led to a greater appreciation of the complexity of piRNA biogenesis and Piwi protein function. Studies performed in other insect species are emerging and promise to add to the current state of the art on the roles of piRNAs and Piwi proteins. Although the primary role of the piRNA pathway is genome defense against transposons, particularly in the germline, recent findings also indicate an expansion of its functions. In this review, an extensive overview is presented of the knowledge of the piRNA pathway that so far has accumulated in insects. Following a presentation of the three major models, data from other insects were also discussed. Finally, the mechanisms for the expansion of the function of the piRNA pathway from transposon control to gene regulation were considered.
Effect of Fruit Volatiles from Native Host Plants on the Sexual Performance of Anastrepha fraterculus sp. 1 Males
Authors: Bachmann Guillermo Enrique , Belliard Silvina Anahí , Devescovi Francisco , Nussenbaum Ana Laura , Fernández Patricia Carina , Vera María Teresa , Ruiz María Josefina , Segura Diego Fernando
Published: February 2023

Anastrepha fraterculus sp.1 males are sexually stimulated by the aroma of fruit of its native host Psidium guajava (guava). Other hosts, which are exotic to A. fraterculus, do not enhance male sexual behavior. Here we evaluate the effects of fruit volatile exposure on male A. fraterculus sp. 1 sexual performance using other native hosts, under the hypothesis that male improvement derives from a common evolutionary history between A. fraterculus sp. 1 and its native hosts. Four species were evaluated: Eugenia myrcianthes, Juglans australis, Psidium cattleianum, and Acca sellowiana. Guava was used as a positive control. Males were exposed to fruit from 12:00 pm to 4:00 pm, from day 8 to day 11 post-emergence. On day 12, we evaluated their calling behavior and mating success. Both guava and P. cattleianum enhanced calling behavior. Mating success was enhanced only by guava and a trend was found for P. cattleianum. Interestingly, the two hosts belong to the Psidium genus. A volatile analysis is planned to identify the compounds responsible for this phenomenon. The other native fruits did not improve the sexual behavior of males. Implications of our findings in the management of A. fraterculus sp. 1 are discussed.
Four-Year Overview of Winter Colony Losses in Greece: Citizen Science Evidence That Transitioning to Organic Beekeeping Practices Reduces Colony Losses
Authors: Kagiali Evangelia , Kokoli Maria , Vardakas Philippos , Goras Georgios , Hatjina Fani , Patalano Solenn
Published: February 2023

The honey bee is one of the most important pollinators with a close relationship to humans. The questionnaire from the non-governmental association “COLOSS”, answered by beekeepers around the world, is a valuable tool for monitoring and analyzing factors involved in overwintering losses, as well as for understanding the evolution of the beekeeping sector over the years. Between 2018–2021, Greece’s participation in this survey involved collecting data from 752 beekeepers and 81,903 hives, from almost the whole country, with a stable balance between professional/non-professional participants and hives, providing a solid representation of the beekeeping practices and winter losses during this period. The results of this study identify a transition towards more natural beekeeping practices concomitant with a significant decrease in winter losses (average losses in 2018: 22.3% and 2019: 24%, dropped in 2020: 14.4% and 2021: 15.3%). Indeed, some factors, such as the increased use of natural landscapes for honey production (from 66.7% usage in 2018 to 76.3% in 2021) and the reduction in the exclusive use of synthetic acaricides (from 24.7% usage in 2018 to 6.7% in 2021) seem to have a significant impact on hive survival. Although these correlations remain to be confirmed experimentally, our study shows that Greek beekeepers follow recommendations and policies toward more sustainable practices. In the future, these trends could be further analyzed and integrated into training programs to strengthen the cooperation and information exchange between citizens and science.
Developing a Questionnaire on Knowledge, Perceptions and Application of Vascular-Aging Measurements
Authors: Triantafyllou Areti , Elia Stavria-Artemis , Park Chloe , Climie Rachel E , Mayer Christopher C. , Mozos Ioana , Pucci Giacomo , Weber Thomas , Panayiotou Andrie G.
Published: February 2023

Background: Vascular age (VA) is independent and chronological age for assessing cardiovascular disease (CVD) risk. However, tools for the implementation of VA are currently lacking. We aimed to develop a questionnaire to assess the current knowledge gaps related to VA and barriers to its implementation in routine practice. Methods: Using a stepwise mixed-method approach, a quantitative questionnaire was constructed in four phases: (1) basic item generation and the development of a semi-qualitative questionnaire (SQQ); (2) dissemination to the VascAgeNet extended network and an analysis of the semi-qualitative questionnaire responses; (3) the development of a quantitative questionnaire (QQ); and (4) an assessment of the content and face validity and internal reliability in an additional sample. Results: Based on six main topics initially identified through an expert panel, a SQQ was developed and disseminated. Finally, a 22-item QQ was developed, with questions grouped around three main themes: knowledge of VA and its risk factors; perceptions and beliefs regarding the importance and contribution of VA to risk classification; and the application of VA measurements in clinical and research practice and its potential limitations (Cronbach’s alpha between 0.920 and 0.982 for all three categories). Conclusion: We report the development of a QQ on VA addressed to both clinicians and non-clinicians aiming to assess their knowledge, perceptions and application of VA measurements.
The Importance of Water for Purification of Longer Carbon Nanotubes for Nanocomposite Applications
Authors: Mordkovich Vladimir Z. , Khaskov Maxim A. , Naumova Veronika A. , De Victor V. , Kulnitskiy Boris A. , Karaeva Aida R.
Published: February 2023

Ultralong carbon nanotubes (UCNTs) are in high demand for nanocomposites applications due to their magnificent physical and chemical properties. UCNTs are synthesized by the catalytic chemical vapor deposition (CCVD) method and, before use as fillers in nanocomposites, should be purified of residual catalyst and non-CNT particles without significant destruction or scissoring of the UCNT. This study investigates the role of water vapor for purification of UCNTs from iron catalyst particles and the importance of water assistance in this process is confirmed. It was shown that wet air treatment of products of UCNTs CCVD synthesis under mild conditions can be used to sufficiently decrease residual iron catalyst content without significant carbon losses in comparison to the results obtained with dry air, while the residual iron content was shown to significantly influence the subsequent oxidation of different forms of carbons, including UCNTs. The increasing of D/G ratio of Raman spectra after wet air treatment of products of UCNTs CCVD synthesis makes it possible to conclude that iron catalyst particles transform into iron oxides and hydroxides that caused inner structural strains and destruction of carbon shells, improving removal of the catalyst particles by subsequent acid treatment. UCNTs purification with water assistance can be used to develop economically and ecologically friendly methods for obtaining fillers for nanocomposites of different applications.
Abnormal Gait Pattern Examination Screening for Physical Activity Level after One Year in Patients with Knee Osteoarthritis
Authors: Yamashina Shunsuke , Harada Kazuhiro , Tanaka Ryo , Inoue Yu
Published: February 2023

This study examined the relationship between abnormal gait pattern and physical activity level one year later in patients with knee osteoarthritis (KOA) and determined the clinical utility of the abnormal gait pattern examination. Initially, the patients’ abnormal gait pattern was assessed using seven items, based on the scoring system reported in a previous study. The grading was based on a three-criteria system with 0: no abnormality, 1: moderately abnormal, and 2: severely abnormal. The patients were then classified into three groups according to physical activity level one year after gait pattern examination: low, intermediate, and high physical activity groups, respectively. Cut-off values for physical activity levels were calculated based on abnormal gait pattern examinations results. On follow-ups with 24 of the 46 subjects, age, abnormal gait pattern, and gait speed showed significant differences among the three groups according to the amount of physical activity. Effect size of abnormal gait pattern was higher than age and gait speed. Patients with KOA with physical activity < 2700 steps/day and <4400 steps/day at one year had abnormal gait pattern examination scores of ≥8 and ≥5, respectively. Abnormal gait pattern is associated with future physical activity. The results suggested that abnormal gait pattern examinations in patients with KOA could be used to screen for the possibility of physical activity being <4400 steps one year later.
The Effect of Schizochytrium sp. on Growth, Fatty Acid Profile and Gut Microbiota of Silver Pomfret (Pampus argenteus)
Authors: Li Yuanbo , Le Qijun , Zhang Man , Xu Shanliang , He Shan , Yan Xiaojun , Hu Jiabao , Wang Yajun
Published: February 2023

Schizochytrium sp. is a kind of heterotrophic protist, rich in docosahexaenoic acid (DHA). To study the application value of Schizochytrium sp. in fish diet, a 20-day feeding experiment was initiated to evaluate its effect on growth, fatty acid contents, and the gut microbiota of the important economic fish, silver pomfret. In this study, the diets of the treatment group were added with 2% Schizochytrium sp. The fish in the treatment group gained more weight and had a higher growth rate than the control group. The levels of DHA, eicosapentaenoic acid, and polyunsaturated fatty acids in the edible tissue of fish were highly increased in the treatment group after 20 days. After feeding Schizochytrium sp., high-throughput 16S rRNA sequencing showed that the Proteobacteria, Firmicutes and Bacteroidetes were the phyla with the highest abundance, and at the genus and species level, we observed an increased abundance of probiotics. The results indicated that ingestion of Schizochytrium sp. could change the dominant microbiota population, which might lead to accelerated growth and improved unsaturated fatty acid content and fish health. This study provides a reference for Schizochytrium sp. supplementation in fish diets and could aid in the industrialization of silver pomfret.
Sensitivity Analysis of Ship Manoeuvring Mathematical Models
Authors: Pires da Silva P. , Sutulo Serge , Guedes Soares C.
Published: February 2023

Sensitivity analysis is applied to ship manoeuvring mathematical models as a means of dealing with model uncertainties, and often leads to model simplifications. A rather standard 3DOF manoeuvring model was tuned with the available results of full-scale trials of a naval combatant and was further used as the reference model for sensitivity analysis. The present research was based on multiple perturbed simulations of the turning, zigzag and spiral manoeuvres. A salient feature of the present study is that the perturbations were applied to the total hydrodynamic forces and moments as well as separately to their characteristic parts, i.e., to the linear and nonlinear single-variable and coupled components. Another special feature is that the deviations of the perturbated responses were estimated not only considering the standard manoeuvring performance indices, but also through application of the Euclidean metric directly to the time histories and to the spiral curve. The performed analysis permitted the sensitivity of the model to be traced to various parameters and groups thereof. It was established that the highest sensitivity of the model was to linear and some nonlinear multivariable parameters, and the Euclidean metric permitted a more detailed analysis than that based only on standard discrete manoeuvring indices. The obtained results are expected to be useful in the application of system identification methods to typical inherently stable fast surface-displacement ships.
Applications of Polyaniline–Alkaline Copper Carbonate Composites for Anti-Bio-Attachment of Concrete in Marine Environments
Authors: Zhou Shaofei , Liang Xu , Gao Jiandong , Ye Bo , Li Chengyu , Qian Jin , Shu Jiangtao , Ye Ying
Published: February 2023

This study proposed the use of polyaniline–alkaline copper carbonate composites as anti-corrosion and anti-biofouling concrete additives and established a set of high-dispersion preparation methods for this composite additive. The effects of polyaniline–alkaline copper carbonate composites in concrete were investigated in marine environments via the preparation of concrete specimens, actual sea suspension experiments, concrete mechanical property tests, and biological attachment avoidance tests. The experimental results showed that (1) the yield of the chemical reactions leading to the preparation of the composite was above 96.46% with a good output. The composite was hydrophilic. The addition of ethylene carbonate as a surfactant and the mixing of the composite into the concrete in a suspension form enabled uniform dispersion of the composite. (2) In the sea waters of Zhoushan, China, bio-attachment was mainly dominated by barnacles and sea anemones. Polyaniline–alkaline copper carbonate composites had good anti-bio-attachment properties and could significantly reduce the amount of bio-attachment in concrete. (3) When the additive content was less than 0.20% of the concrete mass, it did not negatively affect the mechanical properties of the concrete specimens and exerted anti-corrosion and anti-biofouling effects. This reduced the strength loss of concrete and increased the service life of the concrete specimens in the ocean. To ensure the best application effect of the compound in concrete, the recommended content of the compound is 0.05–0.15% of the concrete mass.
Deepwater Artificial Seabed (DAS) Production System: An Innovative Approach to Cost-Effective Deepwater and Ultra-Deepwater Field Developments
Authors: Zhen Xingwei , Lim Frank , Duan Qiuyang , Geng Yiwei , Huang Yi
Published: February 2023

The prevailing offshore field development solutions, i.e., dry tree and wet tree systems, are confronted with serious technical and economic challenges in deep and ultra-deep waters resulting from the large depth of water, far offshore distance, and harsh ocean environmental conditions, as well as high cost. In response to these challenges, an innovative Deepwater Artificial Seabed (DAS) production system is proposed in this article. The DAS production system concentrates on well access and riser design, which enables shallow-water-rated subsea production systems to develop Deepwater (DW) and Ultra-Deepwater (UDW) fields. First, DW & UDW field development drivers are discussed and presented. This is followed by a detailed discussion of the merits and demerits of the prevailing dry tree and wet tree field development solutions. On this basis, the design philosophy and main characteristics of the DAS production system are presented and discussed in detail. Dynamic survival analysis for the fully coupled Floating Production Storage and Offloading (FPSO)-DAS production system is carried out. The artificial seabed stability is systematically investigated for both intact and damaged conditions. The global analysis results indicate that the DAS production system as developed experiences quasi-static responses even under extreme storm conditions, due to the location of the artificial seabed and the decoupling effects of the flexible jumpers. The new DAS production system is considered to be a competitive and cost-effective field development solution in depths of up to 3000 m.
A Multicontinuum-Theory-Based Approach to the Analysis of Fiber-Reinforced Polymer Composites with Degraded Stiffness and Strength Properties Due to Moisture Absorption
Authors: Anderson Evan , Gunawan Budi , Nicholas James , Ingraham Mathew , Hernandez-Sanchez Bernadette A.
Published: February 2023

Marine energy generation technologies such as wave and tidal power have great potential in meeting the need for renewable energy in the years ahead. Yet, many challenges remain associated with marine-based systems because of the corrosive environment. Conventional materials like metals are subject to rapid corrosive breakdown, crippling the lifespan of structures in such environments. Fiber-reinforced polymer composites offer an appealing alternative in their strength and corrosion resistance, but can experience degradation of mechanical properties as a result of moisture absorption. An investigation is conducted to test the application of a technique for micromechanical analysis of composites, known as multicontinuum theory and demonstrated in past works, as a mechanism for predicting the effects of prolonged moisture absorption on the performance of fiber-reinforced composites. Experimental tensile tests are performed on composite coupons with and without prolonged exposure to a salt water solution to obtain stiffness and strength properties. Multicontinuum theory is applied in conjunction with micromechanical modeling to deduce the effects of moisture absorption on the behavior of constituent materials within the composites. The results are consistent with experimental observations when guided by known mechanisms and trends from previous studies, indicating multicontinuum theory as a potentially effective tool in predicting the long-term performance of composites in marine environments.
Navigation Risk Assessment of Autonomous Ships Based on Entropy–TOPSIS–Coupling Coordination Model
Authors: Zhang Wenjun , Zhang Yingjun
Published: February 2023

An autonomous ship refers to a ship that achieves autonomous operation in ship navigation, management, maintenance, cargo transportation and other aspects. Due to the uncertainty in the risks posed by autonomous ship navigation, its risk assessment attracts great attention from researchers. By analyzing the historical accident statistics, this paper gives a comprehensive analysis from the perspective of “Man-Ship-Environment-Management”. In addition, a quantitative evaluation method based on the Entropy–TOPSIS–Coupling coordination model is proposed, which presents a comprehensive assessment of the risks of autonomous ship navigation safety. Furthermore, scientific forecasts and suggestions for improvement are put forward according to the evaluation results.
Seven New Species of the Genus Geastrum (Geastrales, Geastraceae) in China
Authors: Wang Xin , Bau Tolgor
Published: February 2023

Geastrum belongs to Basidiomycota, Agaricomycetes, Geastrales, and Geastraceae. The genus Geastrum exoperidium normally splits at maturity into a characteristic star-like structure. It is a saprophytic fungus with great research significance. Based on morphological observation combined with phylogenetic analysis through ITS and LSU, seven new species of Geastrum belong to four sections, viz., Sect. Myceliostroma, Geastrum laneum; Sect. Exareolata, Geastrum litchi, Geastrum mongolicum; Sect. Corollina, Geastrum pseudosaccatum, Geastrum melanorhynchum, Geastrum oxysepalum; and Sect. Campestria, Geastrum microphole. Illustrated descriptions and the ecological habits of the novel species are provided.
Survey on Dermatophytes Isolated from Animals in Switzerland in the Context of the Prevention of Zoonotic Dermatophytosis
Authors: Fratti Marina , Bontems Olympia , Salamin Karine , Guenova Emmanuella , Monod Michel
Published: February 2023

Most inflammatory dermatophytoses in humans are caused by zoophilic and geophilic dermatophytes. Knowledge of the epidemiology of these fungi in animals facilitates the prevention of dermatophytosis of animal origin in humans. We studied the prevalence of dermatophyte species in domestic animals in Switzerland and examined the effectiveness of direct mycological examination (DME) for their detection compared to mycological cultures. In total, 3515 hair and skin samples, collected between 2008 and 2022 by practicing veterinarians, were subjected to direct fluorescence microscopy and fungal culture. Overall, 611 dermatophytes were isolated, of which 547 (89.5%) were from DME-positive samples. Cats and dogs were the main reservoirs of Trichophyton mentagrophytes and Microsporum canis, whereas Trichophyton benhamiae was predominantly found in guinea pigs. Cultures with M. canis significantly (p < 0.001) outnumbered those with T. mentagrophytes in DME-negative samples (19.3% versus 6.8%), possibly because M. canis can be asymptomatic in cats and dogs, unlike T. mentagrophytes, which is always infectious. Our data confirm DME as a reliable, quick, and easy method to identify the presence of dermatophytes in animals. A positive DME in an animal hair or skin sample should alert people in contact with the animal to the risk of contracting dermatophytosis.
Invasive Aspergillosis after Renal Transplantation
Authors: Sigera Liyanage Shamithra Madhumali , Denning David W.
Published: February 2023

Over 95,000 renal transplantation procedures were completed in 2021. Invasive aspergillosis (IA) affects about 1 in 250 to 1 in 43 renal transplant recipients. About 50% of cases occur in the first 6 months after transplantation; the median time of onset is nearly 3 years. Major risk factors for IA include old age, diabetes mellitus (especially if prior diabetic nephropathy), delayed graft function, acute graft rejection, chronic obstructive pulmonary disease, cytomegalovirus disease, and neutropenia. Hospital construction, demolition activities, and residential refurbishments also increase the risk. Parenchymal pulmonary infection is the most common (~75%), and bronchial, sinus, cerebral, and disseminated disease are less common. Typical pulmonary features of fever, dyspnea, cough, and hemoptysis are seen in most patients, but 20% have non-specific general features of illness. Non-specific infiltrates and pulmonary nodules are the commonest radiological features, with bilateral disease carrying a worse prognosis. Bronchoscopy for direct microscopy, fungal culture, and Aspergillus antigen are the fastest means of establishing the diagnosis; a positive serum Aspergillus antigen presages a worse outcome. Standard therapy includes voriconazole, isavuconazole, or posaconazole, with great attention necessary to assess likely drug–drug interactions. Liposomal amphotericin B and echinocandins are less effective. A reduction in or stopping immunosuppression needs careful consideration, given the overall mortality of IA in renal-transplanted patients; continuing corticosteroid after the diagnosis of IA increases mortality by 2.5 times. Surgical resection or the addition of a gamma interferon should also be considered.
The New GPI-Anchored Protein, SwgA, Is Involved in Nitrogen Metabolism in the Pathogenic Filamentous Fungus Aspergillus fumigatus
Authors: Samalova Marketa , Flamant Patricia , Beau Rémi , Bromley Mike , Moya-Nilges Maryse , Fontaine Thierry , Latgé Jean-Paul , Mouyna Isabelle
Published: February 2023

GPI-anchored proteins display very diverse biological (biochemical and immunological) functions. An in silico analysis has revealed that the genome of Aspergillus fumigatus contains 86 genes coding for putative GPI-anchored proteins (GPI-APs). Past research has demonstrated the involvement of GPI-APs in cell wall remodeling, virulence, and adhesion. We analyzed a new GPI-anchored protein called SwgA. We showed that this protein is mainly present in the Clavati of Aspergillus and is absent from yeasts and other molds. The protein, localized in the membrane of A. fumigatus, is involved in germination, growth, and morphogenesis, and is associated with nitrogen metabolism and thermosensitivity. swgA is controlled by the nitrogen regulator AreA. This current study indicates that GPI-APs have more general functions in fungal metabolism than cell wall biosynthesis.
The Impact of Fintech and Digital Financial Services on Financial Inclusion in India
Authors: Asif Mohammad , Khan Mohd Naved , Tiwari Sadhana , Wani Showkat K. , Alam Firoz
Published: February 2023

India’s financial inclusion has significantly improved during the last several years. In recent years, there has been a rise in the number of Indians who have bank accounts, with this figure believed to be close to 80% at present. Fintech businesses in India are progressively becoming more noticeable as the Government of India (GoI) continues to strive for expanding financial services to the underbanked sector of the population. To reach the underbanked segments of the population and provide a stable operating environment for fintech businesses, India must seek to increase financial inclusion. In this study, regression and correlation were employed, together with secondary data gathered from the RBI, to analyze this influence. The aim was to determine the impact of fintech and digital financial services on financial inclusion in India. According to the results, fintech businesses have significantly aided financial inclusion in this nation, especially for the middle class. These findings will be helpful for policy-makers working hard to bring every individual in this country into an organized financial system.
Site-Specific Phosphorylation of RTK KIT Kinase Insert Domain: Interactome Landscape Perspectives
Authors: Ledoux Julie , Tchertanov Luba
Published: February 2023

The kinase insert domain (KID) of RTK KIT is a key recruitment region for downstream signalling proteins (DSPs). KID, as a multisite phosphorylation region, provides alternative recognition sites for DSPs and activates them by binding a phosphotyrosine (pY) to their SH2 domains. Significant steric, biochemical, and biophysical requirements must be fulfilled by each pair of interacting proteins as the adaptation of their configurations is mandatory for the selective activation of DSPs. The accurate 3D atomistic models obtained by modelling and molecular dynamics (MD) simulations of phosphorylated KID (p-KID) have been delivered to describe KID INTERACTOME. By taking phosphorylated KIDpY721 and the N-terminal SH2 domain of phosphatidylinositol 3-kinase (PI3K), a physiological partner of KID, we showed the two proteins are intrinsically disordered. Using 3D models of both proteins, we probe alternative orientations of KIDpY721 relative to the SH2 binding pocket using automatic docking (HADDOCK) and intuitive user-guided docking. This modelling yields to two possible models of the functionally related non-covalent complex KIDpY721/SH2, where one can be regarded as the first precursor to probe PI3K activation via KIT KID. We suggest that such generation of a KID/SH2 complex is best suited for future studies of the post-transduction effects of RTK KIT.
Is Full-Time Equivalent an Appropriate Measure to Assess L1 and L2 Perception of L2 Speakers with Limited L2 Experience?
Authors: Gorba Celia
Published: February 2023

The revised version of the Speech Learning Model (SLM-r) regards full-time equivalent (FTE), which involves the amount of L2 use during the length of residence (LOR) in an L2 setting, as the main factor in L2 speech acquisition. Previous studiesshowed that LOR has a significant effect on L2 and L1 production and perception but does not explain differences between populations (i.e., L1-Spanish L2-English vs. L1-English L2-Spanish). A reanalysis of the data has been conducted by calculating the FTE of the experienced participants. The aim was also to investigate whether the assumptions of the SLM-r are applicable to L1 and L2 perception. A series of correlation tests between FTE and category boundary—between voiced and voiceless stops—was conducted, yielding non-significant results. The relatively short LOR of participants, the quality of the input and differences in terms of L2 instruction between participants could explain the lack of a clear effect of FTE in this study. Therefore, FTE on its own may not be sufficient to account for L2 accuracy in perception, at least for L2 speakers with limited L2 input, and other factors should be considered.
Towards an RNA/Peptides World by the Direct RNA Template Mechanism: The Emergence of Membrane-Stabilizing Peptides in RNA-Based Protocells
Authors: Shi Yu , Yu Chunwu , Ma Wentao
Published: February 2023

How functional peptides may have arisen is a significant problem for the scenario of the RNA world. An attractive idea, the direct RNA template (DRT) hypothesis, proposes that RNA molecules can bind amino acids specifically and promote the synthesis of corresponding peptides, thereby starting the RNA/peptides world. To investigate the plausibility of this idea, we modeled the emergence of a “membrane-stabilizing peptide” in RNA-based protocells—such a peptide was suggested to have appeared early in the RNA world based on experimental evidence. The computer simulation demonstrated that the protocells containing the “RNA gene” encoding this peptide may spread in the system owing to the peptide’s function. The RNA gene may either originate de novo in protocells or emerge in protocells already containing ribozymes—here we adopt a nucleotide synthetase ribozyme as an example. Furthermore, interestingly, we show that a “nucleotide synthetase peptide” encoded by RNA (also via the DRT mechanism) may substitute the nucleotide synthetase ribozyme in evolution, which may represent how “functional-takeover” in the RNA world could have occurred. Overall, we conclude that the transition from the RNA world towards an RNA/peptides world may well have been mediated by the DRT mechanism. Remarkably, the successful modeling on the emergence of membrane-stabilizing peptide in RNA-based protocells is per se significant, which may imply a “promising” way for peptides to enter the RNA world, especially considering the weak interaction between RNA and the membrane in chemistry.
(Z)-2′-((Adamantan-1-yl)thio)-1,1′-dimethyl-2′,3′-dihydro-[2,4′-biimidazolylidene]-4,5,5′(1H,1′H,3H)-trione
Authors: Burmistrov Vladimir , Mokhov Vladimir , Fayzullin Robert R. , Butov Gennady M.
Published: February 2023

The title compound, (Z)-2′-((adamantan-1-yl)thio)-1,1′-dimethyl-2′,3′-dihydro-[2,4′-biimidazolylidene]-4,5,5′(1H,1′H,3H)-trione, was found to be a by-product of the reaction of 1,3-dehydroadamantane with 3-methyl-2-thioxoimidazolidin-4-one and characterized via single-crystal X-ray diffraction.
Effect of Pulsed Current-Assisted Tension on the Mechanical Behavior and Local Strain of Nickel-Based Superalloy Sheet
Authors: Chen Yuxi , Xu Jie , Guo Bin , Shan Debin
Published: February 2023

Electrically assisted (EA) forming is a plastic forming technique under the coupling action of multiple energy fields, such as force field, temperature field, and electric field. It is suitable for the forming of difficult-to-deform materials such as nickel-based superalloys. In this paper, uniaxial tensile tests on nickel-based superalloy sheets were carried out using the pulsed current assisted with different parameters. The experimental results show that the flow stress of the material decreased with the increase in the current density under a high-frequency pulsed current, and the Joule heating effect explains the flow stress drop. In the pulsed current application process, the different types of Portevin–Le Chatelier phenomena appeared with the increase in the current density. The decrease in elongation assisted by the pulsed current was explained by analyzing the inhomogeneity of the maximum Joule heating temperature distribution. In addition, the digital image correlation (DIC) analysis was used to analyze the local strain behavior of the pulsed current-assisted tensile process. Under the application of a high-frequency pulse current, the specimen exerted an inhomogeneous temperature increase and local hot pressing stress, which resulted in the inhomogeneous distribution of the local strain.
Dynamics of CSBD Healing after Implementation of Dentin and Xenogeneic Bone Biomaterial
Authors: Cvijanović Peloza Olga , Jerbić Radetić Ana Terezija , Baričić Mirjana , Bukovac Luka , Zoričić Cvek Sanja
Published: February 2023

Autologous dentin is frequently used in guided bone regeneration due to its osteoinductive properties, which come from its similarity to native bone. On the other hand, the xenogeneic bone biomaterial Cerabone® serves as a biocompatible, but hardly resorbed biomaterial. During bone healing, an inflammatory, vascular, and osteogenic response occurs in which cytokines such as tumor necrosis factor-alpha (TNF-α), vascular endothelial growth factor (VEGF), and osteopontin (OPN) are released locally and systemically. The aim was to follow up the dynamics (on days 3, 7, 15, 21, and 30) of critical-sized bone defect (CSBD) healing after the implantation of bovine devitalized dentin, rat dentin, and xenogeneic bone biomaterial. For this purpose, histological and histomorphometric methods were employed. Additionally, serum concentrations of TNF-α, VEGF, and OPN were monitored in parallel to better understand the biomaterial-dependent systemic response in rats. At the last time interval, the results showed that the bone defect was bridged over in all three groups of biomaterials. The rat dentin group had the highest percentage of bone volume (BV/TV) and the least percentage of residual biomaterial (RB), which makes it the most optimal biomaterial for bone regeneration. Serum concentrations of the TNF-α, VEGF, and OPN refer to systemic response, which could be linked to intense bone remodeling between days 15 and 21 of the bone healing.
Hot Deformation and Microstructure Evolution of Metallic Materials
Authors: Schindler Ivo
Published: February 2023

Hot plastic deformation is a key method of processing metallic materials and controlling their final properties through structure-forming processes [...]
High-Strength, Degradable and Recyclable Epoxy Resin Based on Imine Bonds for Its Carbon-Fiber-Reinforced Composites
Authors: Jiang Yue , Wang Shuai , Dong Weifu , Kaneko Tatsuo , Chen Mingqing , Shi Dongjian
Published: February 2023

Carbon fiber (CF) is widely used in the preparation of carbon-fiber-reinforced polymer composites (CFRP) in which it is combined with epoxy resin due to its good mechanical properties. Thermosetting bisphenol A epoxy resin, as one of the most common polymer materials, is a non-renewable resource, leading to a heavy environmental burden and resource waste. To solve the above problems and achieve high mechanical and thermal properties comparable to those of bisphenol A, herein, a high-performance, degradable and recyclable bio-based epoxy resin was developed by reacting the lignin derivative vanillin with 4-amino cyclohexanol via Schiff base. This bio-based epoxy resin showed a Young’s modulus of 2.68 GPa and tensile strength of 44 MPa, 36.8% and 15.8% higher than those of bisphenol A epoxy, respectively. Based on the reversible exchange reaction of the imine bond, the resin exhibited good degradation in an acidic environment and was recoverable by heat treatment. Moreover, the prepared epoxy resin could be used to prepare carbon fiber (CF)-reinforced composites. By washing off the epoxy resin, the carbon fiber could be completely recycled. The recovered carbon fiber was well preserved and could be used again for the preparation of composite materials to realize the complete recovery and utilization of carbon fiber. This study opens a way for the preparation of high-performance epoxy resin and the effective recycling of carbon fiber.
Effect of Microstructural Evolution on the Mechanical Properties of Ni-Cr-Mo Ultra-Heavy Steel Plate
Authors: Guo Kaihao , Pan Tao , Zhang Ning , Meng Li , Luo Xiaobing , Chai Feng
Published: February 2023

In this study, microstructural evolution and its effects on mechanical properties across the thickness of a 120 mm Ni-Cr-Mo industrial ultra-heavy steel plate were quantitatively investigated by means of optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM) and electron back-scatter diffraction (EBSD). The results show that the martensite fraction is 65% at 10 mm and disappears at 40 mm, while granular bainite appears at 35 mm and climbs up to as high as 32% at 60 mm, with M-A constituents significantly coarsened. The strength drops with the gradual coarsening of the laths as well as decreased martensite fraction from the surface to the centre. The toughness is mainly affected by the block size and the morphology and quantity of M-A constituents. This study established a multivariate function between the microstructure and toughness (50% fibre area transition temperature, FATT50) with careful consideration of the influence of effective grain size (EGS) and M-A constituent size distribution.
A Comparative Study of Different Poly (Lactic Acid) Bio-Composites Produced by Mechanical Alloying and Casting for Tribological Applications
Authors: Abir Anzum Al , Trindade Bruno
Published: February 2023

The aim of this study was to fabricate different self-lubricating poly (lactic acid)-based bio-composites reinforced with mono- and multi-fillers of carbon fibers, graphene nanoparticles, and a soft Sn-based brazing alloy (Sn89-Zn8-Bi3) using a two-step process consisting of mechanical alloying followed by casting. The results showed that the incorporation of the different fillers on the PLA surface by mechanical alloying was quite homogenous. The volume ratio between the PLA and the fillers was 1:0.02, respectively. The PLA sample reinforced with short carbon fibers and graphene nanoparticles presented the highest hardness (84.5 Shore D, corresponding to a 10% increase compared to PLA) and the lowest specific wear rate (1.5 × 10−4 mm3/N·m, one order of magnitude lower than PLA). With regard to the coefficient of friction, the lowest value was obtained for the sample reinforced with graphene (0.43, corresponding to a decrease of 12% compared to PLA).
Critical Roles of Impurities and Imperfections in Various Phases of Materials
Authors: Yasui Kyuichi
Published: February 2023

In many materials, impurities and imperfections play a critical role on the physical and chemical properties. In the present review, some examples of such materials are discussed. A bulk nanobubble (an ultrafine bubble) is stabilized against dissolution by hydrophobic impurities attached to the bubble surface. An acoustic cavitation threshold in various liquids decreases significantly by the presence of impurities such as solid particles, etc. The strength of brittle ceramics is determined by the size and number of pre-existing microcracks (imperfections) in the specimen. The size effect of a BaTiO3 nanocrystal is influenced by the amount and species of adsorbates (impurities) on its surface as adsorbate-induced charge-screening changes the free energy. The dielectric constant of an assembly of BaTiO3 nanocubes is influenced by a small tilt angle (imperfection) between two attached nanocubes, which induces strain inside a nanocube, and is also influenced by the spatial strain–relaxation due to defects and dislocations (imperfections), resulting in flexoelectric polarization.
Preparation of Anorthite/Mullite In Situ and Phase Transformation in Porcelain
Authors: Lin Shao-Min , Yu Ya-Ling , Zhong Ming-Feng , Yang Huan , Liu Yang , Li Hang , Zhang Chen-Yang , Zhang Zhi-Jie
Published: February 2023

A high sintering temperature is required to acquire excellent performance in the production of porcelain but results in high fuel consumption. To prepare the porcelain with outstanding performance at a lower temperature, a self-produced additive containing calcium (CaK) was added into a three-component system of kaolinite–feldspar–quartz. XRD and SEM were used to characterize the samples. The toughening mechanism and Gibbs free energy were investigated. After introducing the CaK, the bending strength of the porcelain fired at 1513 K increased from 56.32 ± 0.65 MPa to 95.31 ± 0.63 MPa, which was 21.83% higher than that of the porcelain without CaK at an optimal firing temperature of 1603 K. The main crystal phase of the sample comprised mullite and quartz in the raw materials at 1453~1603 K. The anorthite was observed at 1453 K and interlocked with needle-shaped mullite at 1513 K in the porcelain after adding CaK, which resulted in the higher bending strength. Quantitative analysis indicated that the amount of anorthite decreased at 1513 K and disappeared at 1543 K; the amount of mullite increased with temperature. The Gibbs free energy of the reaction (CaO•Al2O3•2SiO2 + 2(Al2O3•2SiO2) → 3Al2O3•2SiO2 + CaO + 4SiO2) at high temperature was negative, which suggested that the formation of mullite (3Al2O3•2SiO2) from anorthite (CaO•Al2O3•2SiO2) was possible. These findings implied that the addition of CaK contributed to the appropriate phase composition and microstructure, and the excellent performance of the porcelain at a lower temperature. In addition, the transformation between anorthite and mullite was possible in the special raw material system. The results are of interest in producing anorthite/mullite ceramics at reduced sintering temperatures and the conversion between anorthite and mullite.
Removal of Methylene Blue from Aqueous Solution by Mixture of Reused Silica Gel Desiccant and Natural Sand or Eggshell Waste
Authors: Juzsakova Tatjana , Salman Ali Dawood , Abdullah Thamer Adnan , Rasheed Rashed Taleb , Zsirka Balázs , Al-Shaikhly Rasha R. , Sluser Brindusa , Cretescu Igor
Published: February 2023

The purpose of this work was to develop, characterize and test new low-cost materials suitable for removing methylene blue dye from water and wastewater by adsorption. The solid materials consisted of silica gel powder (SG), silica gel mixed with eggshell powder (SG-ES) and a mixture of silica gel with sand from the western Iraqi desert (SG-SI). The samples were milled by using an electrical mixer and a ball mill, followed by a drying step. In addition, desert sand was acid-treated in order to remove impurities. The structure and chemical composition of the samples were investigated by X-ray diffraction (XRD), a scanning electron microscopy technique equipped with an energy-dispersive X-ray spectrometer (SEM-EDX), a low-temperature nitrogen adsorption (BET) technique, thermo-analytical (TG/TGA) measurements and Fourier-transformed infrared spectroscopy (FTIR). The previously mentioned materials were tested to remove methylene blue from an aqueous solution. The adsorption experiments were monitored by ultraviolet–visible (UV-Vis) spectrophotometry and showed that SG and SG-ES gave promising results for the methylene blue removal from water. After 40 min of treatment of the aqueous solution containing 10 mg/L of MB at room temperature, the tested SG, SG-ES and SG-SI materials were found to have 86%, 80% and 57% dye adsorption efficiency, respectively. Taking into consideration not only the adsorption activity of the studied material but their availability, cost and concepts of cleaner production and waste minimization, the developed silica gel with eggshell can be considered as a good, cost-effective alternative to commercially available activated-carbon-based adsorbents. Different kinetic and isotherm models were fitted to the experimental results. A pseudo-second-kinetics-order model revealed high correlation fitting, while the Freundlich model was found to appropriately describe the adsorption isotherm. The thermal stability during the possible regeneration process of the SG-ES adsorbent mixture and its interaction mechanism with cationic dye was discussed.
Fatigue-Crack Detection in a Multi-Riveted Strap-Joint Aluminium Aircraft Panel Using Amplitude Characteristics of Diffuse Lamb Wave Field
Authors: Stolze Frank H. G. , Worden Keith , Manson Graeme , Staszewski Wieslaw J.
Published: February 2023

Structural health monitoring of riveted aircraft panels is a real challenge for maintenance engineers. Here, a diffused Lamb wave field is used for fatigue-crack detection in a multi-riveted strap-joint aircraft panel. The panel is instrumented with a network of low-profile surface-bonded piezoceramic transducers. Various amplitude characteristics of Lamb waves are used to extract information on fatigue damage. A statistical outlier analysis based on these characteristics is also performed to detect damage. The experimental work is supported by simplified modelling of wave scattering from crack tips to explain complex response features. The Local Interaction Simulation Approach (LISA) is used for this modelling task. The results demonstrate the potential and limitations of the method for reliable fatigue-crack detection in complex aircraft components.
Effects of Using Aluminum Sulfate as an Accelerator and Acrylic Acid, Aluminum Fluoride, or Alkanolamine as a Regulator in Early Cement Setting
Authors: Zhang Yihong , Wu Yong , Zhou Puyu , Song Zhiyuan , Jia Yayun , Ouyang Weiyi , Luque Rafael , Sun Yang
Published: February 2023

Aluminum sulfate was employed as the main accelerator in order to explore new non-chloride and alkali-free cement accelerators. Acrylic acid, aluminum fluoride, or alkanolamine were used as regulators to further accelerate cement setting. The setting time, compressive, and flexural strengths in cement early strength progress were detected, and both the cement (raw material) and hydrated mortar were fully characterized. The cement setting experiments revealed that only loading acrylic acid as the regulator would decrease the setting time of cement and increase the compressive and flexural strengths of mortar, but further introduction of aluminum fluoride or alkanolamine improved this process drastically. In the meantime, structural characterizations indicated that the raw material (cement) used in this work was composed of C3S (alite), while hydrated mortar consisted of quartz and C3A (tricalcium aluminate). During this transformation, the coordination polyhedron of Al3+ was changed from a tetrahedron to octahedron. This work puts forward a significant strategy for promoting the activity of aluminum sulfate in cement setting and would contribute to the future design of new non-chloride and alkali-free cement accelerators.