bluuebunny/crossref_metadata_2025 huggingface dataset:
The Relationship between Teachers and Peers’ Motivational Climates, Needs Satisfaction, and Physical Education Grades: An AGT and SDT Approach
Authors: Rodrigues Filipe , Monteiro Diogo , Teixeira Diogo S. , Cid Luís
Published: August 2020

Grounded in achievement goal theory and self-determination theory, this study aimed to examine the associations of students’ perception of learning- and performance-oriented climates created by teachers and peers on basic psychological needs satisfaction, and consequently their relationships with physical education grades. This study had a cross-sectional design, and 589 students aged between 10 and 18 years (M = 12.93; SD = 1.49) were recruited for analysis. Participants completed a multisection survey assessing motivational climates and basic psychological needs, and physical education grades were provided by the physical education teacher. Students’ perception of learning-oriented climates created by teachers and peers was positively and significantly associated with basic psychological needs satisfaction. Additionally, these learning-oriented climates presented a significant indirect association with physical education grades. On the other hand, the performance-oriented climate created by teachers had a negative and significant relationship with basic psychological needs satisfaction and displayed a negative indirect relationship with physical education grades. The performance-oriented climate created by peers had a positive and significant relationship with basic psychological needs satisfaction and displayed a positive indirect relationship with physical education grades. The perception of performance-oriented climates created by peers could represent a boost within the students in physical education features. Teachers have the responsibility of promoting task and learning environments in which students experience positive outcomes, not only on a motivational level but also on a cognitive level.
Physical Activity Programs during Pregnancy Are Effective for the Control of Gestational Diabetes Mellitus
Authors: Laredo-Aguilera José Alberto , Gallardo-Bravo María , Rabanales-Sotos Joseba Aingerun , Cobo-Cuenca Ana Isabel , Carmona-Torres Juan Manuel
Published: August 2020

Gestational diabetes mellitus has an incidence of 14% worldwide and nursing is responsible for its monitoring during pregnancy. Excessive weight gain during pregnancy is directly related to gestational diabetes mellitus development. Gestational diabetes mellitus (GDM) has negative repercussions on the evolution of the pregnancy and the fetus. The objective of this systematic review is to establish how physical activity influences pregnant women with gestational diabetes mellitus and to analyze what benefits physical activity has in the control of gestational diabetes mellitus. A systematic search was carried out in different databases (Cochrane, Superior Council of Scientific Investigations (CSIC), EBSCOhost, Pubmed, Scopus, Web os Science, and Proquest) for papers published within the last 12 years, taking into account different inclusion and exclusion criteria. Six randomized controlled studies and one observational case-control study of a high quality were selected. Fasting, postprandial glucose and HbcA1 were assessed, as well as the requirement and amount of insulin used. Thus, there is a positive relationship between the performance of physical activity and the control of gestational diabetes mellitus. Resistance, aerobic exercise, or a combination of both are effective for the control of glucose, HbcA1, and insulin. Due to the variability of the exercises of the analyzed studies and the variability of the shape of the different pregnant women, it does not permit the recommendation of a particular type of exercise. However, any type of physical activity of sufficient intensity and duration can have benefits for pregnant women with GDM. Pregnant women with gestational diabetes mellitus should exercise for at least 20–50 min a minimum of 2 times a week with at a least moderate intensity.
Evaluating Variable Selection and Machine Learning Algorithms for Estimating Forest Heights by Combining Lidar and Hyperspectral Data
Authors: Arjasakusuma Sanjiwana , Swahyu Kusuma Sandiaga , Phinn Stuart
Published: August 2020

Machine learning has been employed for various mapping and modeling tasks using input variables from different sources of remote sensing data. For feature selection involving high- spatial and spectral dimensionality data, various methods have been developed and incorporated into the machine learning framework to ensure an efficient and optimal computational process. This research aims to assess the accuracy of various feature selection and machine learning methods for estimating forest height using AISA (airborne imaging spectrometer for applications) hyperspectral bands (479 bands) and airborne light detection and ranging (lidar) height metrics (36 metrics), alone and combined. Feature selection and dimensionality reduction using Boruta (BO), principal component analysis (PCA), simulated annealing (SA), and genetic algorithm (GA) in combination with machine learning algorithms such as multivariate adaptive regression spline (MARS), extra trees (ET), support vector regression (SVR) with radial basis function, and extreme gradient boosting (XGB) with trees (XGbtree and XGBdart) and linear (XGBlin) classifiers were evaluated. The results demonstrated that the combinations of BO-XGBdart and BO-SVR delivered the best model performance for estimating tropical forest height by combining lidar and hyperspectral data, with R2 = 0.53 and RMSE = 1.7 m (18.4% of nRMSE and 0.046 m of bias) for BO-XGBdart and R2 = 0.51 and RMSE = 1.8 m (15.8% of nRMSE and −0.244 m of bias) for BO-SVR. Our study also demonstrated the effectiveness of BO for variables selection; it could reduce 95% of the data to select the 29 most important variables from the initial 516 variables from lidar metrics and hyperspectral data.
Roles of IL-1 in Cancer: From Tumor Progression to Resistance to Targeted Therapies
Authors: Gelfo Valerio , Romaniello Donatella , Mazzeschi Martina , Sgarzi Michela , Grilli Giada , Morselli Alessandra , Manzan Beatrice , Rihawi Karim , Lauriola Mattia
Published: August 2020

IL-1 belongs to a family of 11 members and is one of the seven receptor-agonists with pro-inflammatory activity. Beyond its biological role as a regulator of the innate immune response, IL-1 is involved in stress and chronic inflammation, therefore it is responsible for several pathological conditions. In particular, IL-1 is known to exert a critical function in malignancies, influencing the tumor microenvironment and promoting cancer initiation and progression. Thus, it orchestrates immunosuppression recruiting pro-tumor immune cells of myeloid origin. Furthermore, new recent findings showed that this cytokine can be directly produced by tumor cells in a positive feedback loop and contributes to the failure of targeted therapy. Activation of anti-apoptotic signaling pathways and senescence are some of the mechanisms recently proposed, but the role of IL-1 in tumor cells refractory to standard therapies needs to be further investigated.
Change the Laminin, Change the Cardiomyocyte: Improve Untreatable Heart Failure
Authors: Hochman-Mendez Camila , Curty Ernesto , Taylor Doris A.
Published: August 2020

No effective medical treatment exists for heart failure with preserved ejection fraction (HFpEF), accounting for approximately half of all heart failure cases. The elevated passive myocardial stiffness in HFpEF is attributed to a combination of alterations in the extracellular matrix (ECM) collagen content and modifications in the sarcomeric protein titin. Here, we propose polylaminin, a biomimetic polymer of laminin, as a promising approach for manipulating the titin isoform shift and phosphorylation in cardiomyocytes. Exploring the pleiotropic effects of polylaminin may be a novel strategy for alleviating symptoms in HFpEF’s multifactorial pathophysiology.
Tepotinib Inhibits the Epithelial–Mesenchymal Transition and Tumor Growth of Gastric Cancers by Increasing GSK3β, E-Cadherin, and Mucin 5AC and 6 Levels
Authors: Sohn Sung-Hwa , Sul Hee Jung , Kim Bohyun , Kim Bum Jun , Kim Hyeong Su , Zang Dae Young
Published: August 2020

Aberrant expression of mucins (MUCs) can promote the epithelial–mesenchymal transition (EMT), which leads to enhanced tumorigenesis. Carcinogenesis-related pathways involving c-MET and β-catenin are associated with MUCs. In this study, we characterized the expression of EMT-relevant proteins including MET, β-catenin, and E-cadherin in human gastric cancer (GC) cell lines, and further characterized the differential susceptibility of these cell lines compared with the c-MET inhibitor tepotinib. We assessed the antitumor activity of tepotinib in GC cell lines. The effects of tepotinib on cell viability, apoptotic cell death, EMT, and c-MET and β-catenin signaling were evaluated by 3-(4,5 dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl-2-(4-sulfophenyl)-2H-tetrazolium (MTS), flow cytometry, Western blotting, and qRT-PCR. The antitumor efficacy was assessed in MKN45 xenograft mice. Tepotinib treatment induced apoptosis in c-MET-amplified SNU620, MKN45, and KATO III cells, but had no effect on c-MET-reduced MKN28 or AGS cells. Tepotinib treatment also significantly reduced the protein levels of phosphorylated and total c-MET, phosphorylated and total ERK, β-catenin, and c-MYC in SNU620 and MKN45 cells. In contrast, this drug was only slightly active against KATO III cells. Notably, tepotinib significantly reduced the expression of EMT-promoting genes such as MMP7, COX-2, WNT1, MUC5B, and c-MYC in c-MET-amplified GC cells and increased the expression of EMT-suppressing genes such as MUC5AC, MUC6, GSK3β, and E-cadherin. In a mouse model, tepotinib exhibited good antitumor growth activity along with increased E-cadherin and decreased phosphorylated c-MET (phospho-c-MET) protein levels. Collectively, these results suggest that tepotinib suppresses tumor growth and migration by negatively regulating c-MET-induced EMT. These findings provide new insights into the mechanism by which MUC5AC and MUC6 contribute to GC progression.
Drug Resistance in Hematological Malignancies
Authors: Auberger Patrick , Tamburini-Bonnefoy Jerome , Puissant Alexandre
Published: August 2020

Hematological malignancies define a highly heterogeneous set of blood-, bone marrow-, and organ-associated diseases with highly variable prognoses that constantly relapse upon treatment [...]
Editorial for Special Issue: Test and Evaluation Methods for Human-Machine Interfaces of Automated Vehicles
Authors: Naujoks Frederik , Hergeth Sebastian , Keinath Andreas , Schömig Nadja , Wiedemann Katharina
Published: August 2020

Today, OEMs and suppliers can rely on commonly agreed and standardized test and evaluation methods for in-vehicle human–machine interfaces (HMIs). These have traditionally focused on the context of manually driven vehicles and put the evaluation of minimizing distraction effects and enhancing usability at their core (e.g., AAM guidelines or NHTSA visual-manual distraction guidelines). However, advances in automated driving systems (ADS) have already begun to change the driver’s role from actively driving the vehicle to monitoring the driving situation and being ready to intervene in partially automated driving (SAE L2). Higher levels of vehicle automation will likely only require the driver to act as a fallback ready user in case of system limits and malfunctions (SAE L3) or could even act without any fallback within their operational design domain (SAE L4). During the same trip, different levels of automation might be available to the driver (e.g., L2 in urban environments, L3 on highways). These developments require new test and evaluation methods for ADS, as available test methods cannot be easily transferred and adapted. The shift towards higher levels of vehicle automation has also moved the discussion towards the interaction between automated and non-automated road users using exterior HMIs. This Special Issue includes theoretical papers a well as empirical studies that deal with these new challenges by proposing new and innovative test methods in the evaluation of ADS HMIs in different areas.
Mechanical and Thermal Analyses of Metal-PLA Components Fabricated by Metal Material Extrusion
Authors: Mohammadizadeh Mahdi , Lu Hao , Fidan Ismail , Tantawi Khalid , Gupta Ankit , Hasanov Seymur , Zhang Zhicheng , Alifui-Segbaya Frank , Rennie Allan
Published: August 2020

Metal additive manufacturing (AM) has gained much attention in recent years due to its advantages including geometric freedom and design complexity, appropriate for a wide range of potential industrial applications. However, conventional metal AM methods have high-cost barriers due to the initial cost of the capital equipment, support, and maintenance, etc. This study presents a low-cost metal material extrusion technology as a prospective alternative to the production of metallic parts in additive manufacturing. The filaments used consist of copper, bronze, stainless steel, high carbon iron, and aluminum powders in a polylactic acid matrix. Using the proposed fabrication technology, test specimens were built by extruding metal/polymer composite filaments, which were then sintered in an open-air furnace to produce solid metallic parts. In this research, the mechanical and thermal properties of the built parts are examined using tensile tests, thermogravimetric, thermomechanical and microstructural analysis.
Antimicrobial Effectiveness of Calcium Silicate Sealers against a Nutrient-Stressed Multispecies Biofilm
Authors: Bose Rahul , Ioannidis Konstantinos , Foschi Federico , Bakhsh Abdulaziz , Kelly Robert D. , Deb Sanjukta , Mannocci Francesco , Niazi Sadia Ambreen
Published: August 2020

Purpose: This study compared the antimicrobial efficacy of calcium silicate sealers (BioRoot RCS and Total Fill BC) and conventional sealers (AH Plus and Tubli-seal) against planktonic bacteria and a nutrient-stressed multispecies biofilm. Methods: Antimicrobial properties of freshly mixed sealers were investigated using the direct contact test (DCT) and a nutrient-stressed multispecies biofilm comprised of five endodontic strains. Antimicrobial activity was determined using quantitative viable counts and confocal laser scanning microscopy (CLSM) analysis with live/dead staining. The pH of the sealers was analysed over a period of 28 days in Hanks Balanced Salt Solution (HBSS). Analysis of variance (ANOVA) with Tukey tests and the Kruskal–Wallis test were used for data analysis with a significance of 5%. Results: All endodontic sealers exhibited significant antimicrobial activity against planktonic bacteria (p < 0.05). BioRoot RCS caused a significant reduction in viable counts of the biofilms compared to AH Plus and the control (p < 0.05), while no significant difference could be observed compared to TotalFill BC and Tubli-seal (p > 0.05). CLSM analysis showed that BioRoot RCS and TotalFill BC exhibited significant biofilm inhibition compared to Tubli-seal, AH Plus and the control (p < 0.05). BioRoot RCS presented with the highest microbial killing, followed by TotalFill BC and Tubli-seal. Alkalizing activity was seen from the onset by BioRoot RCS, TotalFill BC and AH Plus. After 28 days, BioRoot RCS demonstrated the highest pH in HBSS (pH > 12). Conclusions: Calcium silicate sealers exhibited effective antimicrobial properties. This was demonstrated by superior biofilm inhibition capacity and microbial killing, with strong alkalizing activity compared to epoxy-based and zinc oxide-eugenol-based sealers.
Oral and Fecal Microbiota in Lynch Syndrome
Authors: Ferrarese Roberto , Zuppardo Raffaella Alessia , Puzzono Marta , Mannucci Alessandro , Amato Virginia , Ditonno Ilaria , Patricelli Maria Grazia , Raucci Annalisa Russo , Clementi Massimo , Elmore Ugo , Rosati Riccardo , Testoni Pier Alberto , Mancini Nicasio , Cavestro Giulia Martina
Published: August 2020

Background: The role of microbiota in Lynch syndrome (LS) is still under debate. We compared oral and fecal microbiota of LS saliva and stool samples with normal healthy controls (NHC). Methods: Total DNA was purified from feces and saliva to amplify the V3–V4 region of the 16s rRNA gene. Sequences with a high-quality score and length >250 bp were used for taxonomic analysis with QIIME software. Results: Compared to NHC, LS fecal samples demonstrated a statistically significant increase of Bacteroidetes and Proteobacteria and a significant decrease of Firmicutes at the phylum level and of Ruminococcaceae at the family level. Moreover, LS oral samples exhibited a statistically significant increase of Veillonellaceae and Leptotrichiaceae and a statistically significant decrease of Pasteurellaceae. A beta-diversity index allowed differentiation of the two groups. Conclusions: A peculiar microbial signature is associated with LS, similar to that of sporadic colorectal cancer and Crohn’s disease. These data suggest a possible role of proinflammatory bacteria in tumor development in a condition of genetic predisposition, such as LS.
Multi-Ship Collision Avoidance Decision-Making Based on Collision Risk Index
Authors: Hu Yingjun , Zhang Anmin , Tian Wuliu , Zhang Jinfen , Hou Zebei
Published: August 2020

Most maritime accidents are caused by human errors or failures. Providing early warning and decision support to the officer on watch (OOW) is one of the primary issues to reduce such errors and failures. In this paper, a quantitative real-time multi-ship collision risk analysis and collision avoidance decision-making model is proposed. Firstly, a multi-ship real-time collision risk analysis system was established under the overall requirements of the International Code for Collision Avoidance at Sea (COLREGs) and good seamanship, based on five collision risk influencing factors. Then, the fuzzy logic method is used to calculate the collision risk and analyze these elements in real time. Finally, decisions on changing course or changing speed are made to avoid collision. The results of collision avoidance decisions made at different collision risk thresholds are compared in a series of simulations. The results reflect that the multi-ship collision avoidance decision problem can be well-resolved using the proposed multi-ship collision risk evaluation method. In particular, the model can also make correct decisions when the collision risk thresholds of ships in the same scenario are different. The model can provide a good collision risk warning and decision support for the OOW in real-time mode.
Phylogenetic and Chemotaxonomic Studies Confirm the Affinities of Stromatoneurospora phoenix to the Coprophilous Xylariaceae
Authors: Becker Kevin , Wongkanoun Sarunyou , Wessel Anna-Charleen , Bills Gerald F. , Stadler Marc , Luangsa-ard J. Jennifer
Published: August 2020

The genus Stromatoneurospora was erected in 1973 by Jong and Davis to accommodate the pyrophilic pyrenomycete Sphaeria phoenix and has traditionally been placed in the family Xylariaceae based on morphological features. However, no living culture of this genus has so far been available in the public domain. Molecular data were restricted to an internal transcribed spacer (ITS) sequence that only confirmed the familial position, and was generated from a strain that is not deposited in a public culture collection. We have recently collected fresh material and were able to culture this fungus from Thailand. The secondary metabolites of this strains were analysed after fermentation in multiple media. The the prominent components of these fermentation were purified, using preparative chromatography. Aside from two new eremophilane sesquiterpenoids named phoenixilanes A–B (1–2), four other components that are known from species of the xylariaceous genera Xylaria and Poronia were identified by spectral methods (nuclear magnetic resonance spectroscopy and high resolution mass spectrometry). Notably, (−)-(R)-6-hydroxy-3-methyl-4-dihydroisocoumarin-5-carboxylic acid (6) has not been reported as a natural product before. Moreover, DNA sequences of Stromatoneurospora phoenix clustered with members of the genera Poronia and Podosordaria in a multi-locus molecular phylogeny. These results confirmed that the genus belongs to the same evolutionary lineage as the coprophilic Xylariaceae. The results also suggest that this lineage has evolved independently from the plant-inhabiting saprotrophs and endophytes that are closely related to the genus Xylaria. These findings are discussed in relation to some theories about the endophytic vs. the pyrophilic/coprophilic fungal life style.
Circulating MicroRNAs as Prognostic and Therapeutic Biomarkers in Breast Cancer Molecular Subtypes
Authors: Zelli Veronica , Compagnoni Chiara , Capelli Roberta , Cannita Katia , Sidoni Tina , Ficorella Corrado , Capalbo Carlo , Zazzeroni Francesca , Tessitore Alessandra , Alesse Edoardo
Published: August 2020

Breast cancer (BC) is a common and heterogeneous disease, of which six molecular subtypes, characterized by different biological features and clinical outcomes, were described. The identification of additional biomarkers able to further connote and distinguish the different BC subtypes is essential to improve the diagnostic, prognostic and therapeutic strategies in BC patients. MicroRNAs (miRNAs) are short non-coding RNA involved in several physiological and pathological processes, including cancer development and progression. In particular, circulating miRNAs, which can be found in an adequately stable structure in serum/plasma of cancer patients, are emerging as very promising non-invasive biomarkers. Several studies have analyzed the potential role of circulating miRNAs as prognostic and therapeutic markers in BC. In the present review we describe circulating miRNAs, identified as putative biomarker in BC, with special reference to different BC molecular subtypes.
Diagnostic and Prognostic Significance of MiR-150 in Colorectal Cancer: A Systematic Review and Meta-Analysis
Authors: Sur Daniel , Burz Claudia , Sabarimurugan Shanthi , Irimie Alexandru
Published: August 2020

Although treatment options have improved, the survival and quality of life of colorectal cancer (CRC) patients remain dismal. Therefore, significant biomarker prediction may help to improve colorectal cancer patient’s prognosis profile. MiRNAs have come as an option because of their essential role in cancer initiation and progression by regulating several molecular processes. MiR-150 has different roles in cancer, but its function in CRC is still ambiguous. We undertook a systematic review and meta-analysis according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) research criteria by interrogating several databases in order to assess the diagnostic accuracy and prognostic value of miR-150. Additionally, clinicalgov.org was scanned for possible trials. The literature was screened from inception to February 2020. A total of 12 out of 70 full-text articles were included in the meta-analysis. Among these, nine studies were included for diagnostic accuracy, and the remaining three were considered for prognostic significance of miR-150. With our results, miR-150 is an appropriate diagnostic biomarker, especially in serum and plasma, while the prognostic value of miR-150 was not statistically significant. The present study findings suggest that miR-150 has high specificity and sensitivity values as a potential diagnostic biomarker in colorectal cancer patients.
Land Use Transition and Its Eco-Environmental Effects in the Beijing–Tianjin–Hebei Urban Agglomeration: A Production–Living–Ecological Perspective
Authors: Yang Yuanyuan , Bao Wenkai , Li Yuheng , Wang Yongsheng , Chen Zongfeng
Published: August 2020

With the rapid development of urbanization and industrialization, China’s metropolitan areas have experienced dramatic transitions of land use, which has had a profound impact on the eco-environment. Accordingly, the contradictions of regional production, living, and ecological spaces have intensified. In this context, analysis of the dynamics of regional production–living–ecological (PLE) spaces has become an important entry point for studying land use transition and its eco-environmental effects, by constructing a classification system of PLE land functions. Using remote sensing data from four periods from 1985 to 2018, this paper explores the spatiotemporal evolution characteristics of PLE spaces and their eco-environmental effects in the Beijing–Tianjin–Hebei (BTH) urban agglomeration, based on GIS and the InVEST model. The results revealed that from 1985 to 2018, the living space of the BTH region expanded rapidly, the production space gradually shrank, and the ecological land remained relatively stable. The eco-environmental quality index within the study area shows obvious regional differences, demonstrating the spatial distribution of “high in the northwest and low in the southeast”, and an overall deteriorating trend in the past 33 years. Moreover, the carbon density decreased gradually from northwest to southeast, and the transformations from production land into living land and from ecological land into production land were the major types of eco-environment deterioration. Our findings will provide guidelines for land use management, and offer references for the functional division of PLE spaces and ecological civilization construction, especially in terms of the coordinated development of the BTH region.
Managing Conflicts with Local Communities over the Introduction of Renewable Energy: The Solar-Rush Experience in Japan
Authors: Akita Noriko , Ohe Yasuo , Araki Shoko , Yokohari Makoto , Terada Toru , Bolthouse Jay
Published: August 2020

A worldwide introduction of renewable energy has been required to reduce greenhouse gas emissions. Concomitantly, this has caused conflict between renewable energy development and local communities over landscape changes. This study aims to clarify the factors of conflict and find a way of conflict management. A case study on Japan is used, where a solar rush occurred due to the feed-in tariff (FIT) system. We analyze the public reasons to worry about renewable energy and the spatial characteristics of its locations. A socio-spatial approach is used by first utilizing a qualitative survey based on questionnaires and interviews with the local governments to understand the awareness regarding the issues, and then utilizing a quantitative survey on the location changes to solar power by using GIS. The results suggest that there were links between local governments’ concerns and the location of solar power concentration. These results show that conflicts over renewable energy are not unavoidable and may be managed by local governments that can act as intermediaries with sufficient knowledge of the local communities.
Comparative Tribological Properties of Pd-, Pt-, and Zr-Based Bulk Metallic Glasses
Authors: Medina Marco A. , Acikgoz Ogulcan , Rodriguez Anthony , Meduri Chandra S. , Kumar Golden , Baykara Mehmet Z.
Published: August 2020

We present a comparative study of the tribological properties of Pd-, Pt-, and Zr-based bulk metallic glasses (BMG-Pd, BMG-Pt, and BMG-Zr, respectively) under unlubricated conditions. In particular, micro-tribometry is utilized with a 52,100 steel ball, showing that BMG-Pt exhibits a significantly higher coefficient of friction (COF) (0.58 ± 0.08) when compared with BMG-Pd (0.30 ± 0.02) and BMG-Zr (0.20 ± 0.03). Topographical roughness on and off wear scars is characterized via atomic force microscopy (AFM), with results that do not correlate with the observed frictional behavior. On the other hand, scanning electron microscopy (SEM) is utilized to reveal contrasting wear mechanisms for the three samples: while BMG-Pd and BMG-Zr exhibit predominantly abrasive wear, there is evidence of adhesive wear on BMG-Pt. Consequently, the occurrence of adhesive wear emerges as a potential mechanism behind the observation of relatively high coefficients of friction on BMG-Pt, suggesting stronger interactions with steel when compared with the other BMG samples.
An Overview of Grease Water Resistance
Authors: Gurt Alan , Khonsari Michael
Published: August 2020

Many grease-lubricated components operate in wet environments, making them susceptible to water contamination which degrades their performance, functionality, and useful life. Hence, selecting a grease with appropriate water-resistant properties can have a significant influence on the life of the machine. While industry standards attempt to evaluate a grease’s water resistance, research indicates that a more thorough understanding of water resistance is needed to properly match a grease to an application. This paper provides an overview of the interaction of grease and water, covers existing water-resistance standards, discusses the results of available experiments aiming to describe the effects of water on grease, demonstrates the need for more meaningful standards, and suggests additional measures for characterizing a grease’s water resistance.
Dry-Jet Wet Spinning of Thermally Stable Lignin-Textile Grade Polyacrylonitrile Fibers Regenerated from Chloride-Based Ionic Liquids Compounds
Authors: Al Aiti Muhannad , Das Amit , Kanerva Mikko , Järventausta Maija , Johansson Petri , Scheffler Christina , Göbel Michael , Jehnichen Dieter , Brünig Harald , Wulff Lucas , Boye Susanne , Arnhold Kerstin , Kuusipalo Jurkka , Heinrich Gert
Published: August 2020

In this paper, we report on the use of amorphous lignin, a waste by-product of the paper industry, for the production of high performance carbon fibers (CF) as precursor with improved thermal stability and thermo-mechanical properties. The precursor was prepared by blending of lignin with polyacrylonitrile (PAN), which was previously dissolved in an ionic liquid. The fibers thus produced offered very high thermal stability as compared with the fiber consisting of pure PAN. The molecular compatibility, miscibility, and thermal stability of the system were studied by means of shear rheological measurements. The achieved mechanical properties were found to be related to the temperature-dependent relaxation time (consistence parameter) of the spinning dope and the diffusion kinetics of the ionic liquids from the fibers into the coagulation bath. Furthermore, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical tests (DMA) were utilized to understand in-depth the thermal and the stabilization kinetics of the developed fibers and the impact of lignin on the stabilization process of the fibers. Low molecular weight lignin increased the thermally induced physical shrinkage, suggesting disturbing effects on the semi-crystalline domains of the PAN matrix, and suppressed the chemically induced shrinkage of the fibers. The knowledge gained throughout the present paper allows summarizing a novel avenue to develop lignin-based CF designed with adjusted thermal stability.
New Insight into Phase Transitions of Porous Glass-Based Ferroelectric Nanocomposites
Authors: Rysiakiewicz-Pasek Ewa , Antropova Tatiana , Polyakova Irina , Pshenko Olga , Ciżman Agnieszka
Published: August 2020

The results of XRD, FTIR and differential scanning calorimetry (DSC) studies of empty porous silica matrices filled with binary mixtures of K1–xAgxNO3 (x = 0.05, 0.10) are reported in comparison with those obtained for bulk salts in the temperature range of structural phase transitions. Scanning electron microscopic data of the studied empty macroporous and microporous glasses confirmed differences in the pore morphology associated with the presence of silica gel. Accordingly, XRD and FTIR samples contain crystalline phase of KNO3 and AgNO3. The results of calorimetric investigation of porous glasses filled with binary mixtures of K1–xAgxNO3 (x = 0.05, 0.10) are presented. The results show that in the K1–xAgxNO3 nanocomposites, anomalies associated with phase transitions were detected. An influence of the mean value of pores sizes on the ferroelectric phase transition temperatures of K1–xAgxNO3 nanocrystals embedded into the porous matrices was determined. The impact of pore space structure on the phase transitions of ferroics nanocomposites was discussed.
Shear Deformation Behavior of a Double-Layer Asphalt Mixture Based on the Virtual Simulation of a Uniaxial Penetration Test
Authors: Kou Changjiang , Pan Xiaohui , Xiao Peng , Kang Aihong , Wu Zhengguang
Published: August 2020

This paper aims to clarify the shear deformation behavior of double-layer asphalt mixtures using the virtual uniaxial penetration test (UPT) with a discrete element method. For this purpose, asphalt mixtures with two different nominal maximum aggregate sizes were designed for the preparation of double-layer wheel tracking test specimens. Then, the cylindrical cores were prepared from the specimens and were cut for capturing the longitudinal profile images. These images were used to reconstruct a two-dimensional discrete element model (DEM) of the uniaxial penetration test specimen. The results indicate that the shear deformation behavior of the asphalt mixtures showed corresponding changes under the virtual loading. The tensile and compressive stress were distributed unevenly within the upper layer after the test, and both coarse aggregates and asphalt mortars bore a greater shear stress. Therefore, cracks were more likely to occur in the upper layer, leading to the failure of the specimens. This process enhanced the bonding between the asphalt mortars and the mineral aggregates. The aggregate particles in the upper layer moved more vertically, while those in the lower layer generally moved more laterally under the virtual loading. This behavior reveals the rutting mechanism of asphalt pavement.
Synthesis and Adsorption Properties of Novel Bacterial Cellulose/Graphene Oxide/Attapulgite Materials for Cu and Pb Ions in Aqueous Solutions
Authors: Song Shen , Liu Zhao , Zhang Ji , Jiao Caizhen , Ding Ling , Yang Shengrong
Published: August 2020

Removing heavy metal ions from industrial wastewater is one of the most important and difficult areas of the water treatment industry. In this study, Bacterial Cellulose/Polyvinyl Alcohol/Graphene Oxide/Attapulgite (BC/PVA/GO/APT) composites were successfully prepared via a repeated freeze-thaw method using bacterial cellulose, polyvinyl alcohol as the skeleton, and graphene oxide, attapulgite as fillers. The capacities of adsorbing Cu2+ and Pb2+ ions in solution were investigated. FTIR, XRD, SEM, BET, and TG-DSC analyses showed that the BC/PVA/GO/APT hydrogel has a better hydrophilicity, a larger specific surface area and a better thermal stability than traditional materials. We found that the adsorption of Cu2+ and Pb2+ ions can be accurately predicted by the Freundlich kinetic model, and the optimal adsorption capacities of these ions were found to be 150.79 mg/g and 217.8 mg/g respectively. Thermodynamic results showed that the adsorption process is spontaneous and exothermic. BC/PVA/GO/APT composites are suggested to be an ideal adsorption material for removing heavy metal ions from industrial wastewater.
Influence of the Size and Type of Pores on Brick Resistance to Freeze-Thaw Cycles
Authors: Netinger Grubeša Ivanka , Vračević Martina , Ducman Vilma , Marković Berislav , Szenti Imre , Kukovecz Ákos
Published: August 2020

This paper estimates the frost resistance of bricks using the ratio of compressive strength before freezing to compressive strength after freezing to describe the damage degree of bricks being exposed to freeze-thaw cycles. In an effort to find the ratio that clearly distinguishes resistant bricks from non-resistant bricks, the authors attempted to establish the correlation between the ratio and Maage factor as a recognized model for assessing brick resistance. To clarify the degree of damage of individual bricks, the pore size distribution has been investigated by means of mercury porosimetry. Additionally, micro computed X-ray tomography (micro-CT) has been employed to define the influence of the type of pores (open or closed) and their connectivity on the frost resistance of bricks. According to the results, it can be concluded that there is a good correlation between the Maage factor and the ratio of pre- to post-freeze-thaw cycle compressive strengths, and that the latter ratio strongly correlates with the percentage of large pores (≥3 mm) in the brick. If such a correlation could be confirmed in a larger sample, then the ratio of pre- to post-freeze-thaw cycle compressive strengths could be used as a new method for assessing brick resistance to freeze-thaw cycles and it would be possible to determine the minimum percentage of large pores required to ensure the overall resistance of brick to freeze-thaw conditions. The complexity of the problem is, however, evidenced by the fact that no clear connection between the type (open versus closed) or connectivity of pores and the frost resistance of bricks could be revealed by micro-CT.
Visible Light-Enhanced Antibacterial and Osteogenic Functionality of Au and Pt Nanoparticles Deposited on TiO2 Nanotubes
Authors: Moon Kyoung-Suk , Choi Eun-Joo , Bae Ji-Myung , Park Young-Bum , Oh Seunghan
Published: August 2020

This study aimed at evaluating the visible light mediated antimicrobial and osteogenic applications of noble metal, such as gold (Au) and platinum (Pt) coated titania (TiO2) nanotubes (NTs). In this study, the Au and Pt nanoparticles (NPs) were deposited on anodized 100 nm TiO2 NTs by ion plasma sputtering. The Au and Pt NPs were mainly deposited on the top surface layer of TiO2 NTs and showed light absorbance peaks around the 470 and 600 nm visible light region used in this study, as seen from the surface characterization. From the results of antibacterial activity test, Au and Pt NPs that were deposited on TiO2 NTs showed excellent antibacterial activity under 470 nm visible light irradiation due to the plasmonic photocatalysis based on the localized surface plasmon resonance effect of the Au and Pt NPs. In addition, alkaline phosphate activity test and quantitative real-time PCR assay of osteogenic related genes resulted that these NPs promoted the osteogenic functionality of human mesenchymal stem cells (hMSCs) under 600 nm visible light irradiation, because of the synergic effect of the photothermal scattering of noble metal nanoparticles and visible light low-level laser therapy (LLLT). Therefore, the combination of noble metal coated TiO2 NTs and visible light irradiation would be expected to perform permanent antibacterial activity without the need of an antibacterial agent besides promoting osteogenic functionality.
Seismic Behavior of Extended End-Plate Connections Subjected to Cyclic Loading on the Top-Side of the Column
Authors: Luo Liang , Qin Jiangui , Zhao Dongzhuo , Wu Zhiwei
Published: August 2020

The extended end-plate connections provide excellent performance in resisting seismic loads in high-risk areas. Most scholars’ experiments and finite element studies on this type of joint are focused on the method of applying displacement loads on the beam tip, while the method of applying displacement on the column side has not been the subject of further study. However, the load transmission mechanism of this type of connection is not completely consistent in actual engineering, as the design concept of “strong column weak beam” does not apply to all joints. Therefore, in this paper, the lateral displacement of the applied column is used to simulate the seismic horizontal force to study the mechanical properties of the connection joints of the “weak column and strong beam” under the limit state of earthquake action. Based on the two internal columns (IC-EP1/2) and two edge columns (EC-EP1/2), the failure modes, strength, stiffness, moment–rotation curve, skeleton curve, ductility, and energy dissipation of this type of connection were studied. Experiment results indicated that this type of connection features semi-rigid and partial strength joints. The connection rotation angle of all specimens in the test exceeds 0.05 rad, which suggests it is an ideal seismic joints. Besides, the relationship between the thickness of the end-plate and the diameter of the bolt has a greater impact on the failure mode of the joint. The finite element (FE) analysis models were established for the above connection. The numerical model was validated against experimental results and showed acceptable consistency.
Long-Term Sorption and Solubility of Zirconia-Impregnated PMMA Nanocomposite in Water and Artificial Saliva
Authors: Zidan Saleh , Silikas Nikolaos , Haider Julfikar , Yates Julian
Published: August 2020

Exposure of denture base acrylic resins to the oral environment and storage media for extended periods of time results in sorption of saliva or water, leading to a reduction in physical properties and thus clinical service life. The purpose of this in vitro study was to assess the sorption and solubility of high-impact heat-polymerised denture base acrylic resin (HI PMMA) impregnated with zirconia nanoparticles after being stored for 180 days in distilled water (DW) and artificial saliva (AS). The specimens were divided into six groups for each storage medium, according to the concentration of zirconia nanoparticles (0, 1.5, 3.0, 5.0, 7.0, and 10.0 wt.%). Data were statistically analysed for sorption and solubility using one-way and two-way ANOVA statistical tests. Sorption in DW and AS for all groups containing zirconia showed sorption values lower than the control group at 90 days, though not significantly different (p > 0.05) compared to the control group. For both the DW and AS groups, the lowest solubility value was measured in the group containing 3 wt.% zirconia, however, there was no significant difference compared to the control group except when observing 10 wt.% zirconia in AS, which showed a significantly higher solubility (p < 0.05). High-impact PMMA, impregnated with low concentrations of ZrO2, showed the lowest sorption and solubility in both media, but was not significantly different compared to pure HI PMMA.
Frictional Behaviour of Composite Anodized Layers on Aluminium Alloys
Authors: Atraszkiewicz Radomir , Makówka Marcin , Kołodziejczyk Łukasz , Januszewicz Bartłomiej , Sucharkiewicz Jan
Published: August 2020

Three variants of the micro arc oxidation (MAO) technique have been used to treat a 2017A alloy surface. The first variant was a pure anodized layer, the second an anodized layer with SiC embedded nanoparticles and the third an anodized layer with Si3N4 nanoparticles. Tribological tests were performed for all variants, on three samples for every case. Friction coefficients and wear rates were calculated on the basis of experiments. The pure anodized layer manifested friction coefficient values within the range of 0.48 ÷ 0.52 and a wear rate in the range ~10−15 m3N−1m−1. SiC nanoparticles improved the tribological properties of the layer, as indicated by a reduction of the friction coefficient values to the range of 0.20 ÷ 0.26 with preserved very high resistance against wear (wear rate ~10−15 m3N−1m−1). Si3N4 particles embedded in anodized layer deteriorated the tribological properties, with a reduction in the resistance against fatigue and wear, intensification of friction forces and a change in the nature of friction contact behavior to more abrasive-like nature (friction coefficients ranging from 0.4 to 0.6 and wear rates ~10−14 m3N−1m−1).
A Hybrid Artificial Neural Network to Estimate Soil Moisture Using SWAT+ and SMAP Data
Authors: Breen Katherine H. , James Scott C. , White Joseph D. , Allen Peter M. , Arnold Jeffery G.
Published: August 2020

In this work, we developed a data-driven framework to predict near-surface (0–5 cm) soil moisture (SM) by mapping inputs from the Soil & Water Assessment Tool to SM time series from NASA’s Soil Moisture Active Passive (SMAP) satellite for the period 1 January 2016–31 December 2018. We developed a hybrid artificial neural network (ANN) combining long short-term memory and multilayer perceptron networks that were used to simultaneously incorporate dynamic weather and static spatial data into the training algorithm, respectively. We evaluated the generalizability of the hybrid ANN using training datasets comprising several watersheds with different environmental conditions, examined the effects of standard and physics-guided loss functions, and experimented with feature augmentation. Our model could estimate SM on par with the accuracy of SMAP. We demonstrated that the most critical learning of the physical processes governing SM variability was learned from meteorological time series, and that additional physical context supported model performance when test data were not fully encapsulated by the variability of the training data. Additionally, we found that when forecasting SM based on trends learned during the earlier training period, the models appreciated seasonal trends.
Frequency and Severity Dependence in the Collective Risk Model: An Approach Based on Sarmanov Distribution
Authors: Bolancé Catalina , Vernic Raluca
Published: August 2020

In actuarial mathematics, the claims of an insurance portfolio are often modeled using the collective risk model, which consists of a random number of claims of independent, identically distributed (i.i.d.) random variables (r.v.s) that represent cost per claim. To facilitate computations, there is a classical assumption of independence between the random number of such random variables (i.e., the claims frequency) and the random variables themselves (i.e., the claim severities). However, recent studies showed that, in practice, this assumption does not always hold, hence, introducing dependence in the collective model becomes a necessity. In this sense, one trend consists of assuming dependence between the number of claims and their average severity. Alternatively, we can consider heterogeneity between the individual cost of claims associated with a given number of claims. Using the Sarmanov distribution, in this paper we aim at introducing dependence between the number of claims and the individual claim severities. As marginal models, we use the Poisson and Negative Binomial (NB) distributions for the number of claims, and the Gamma and Lognormal distributions for the cost of claims. The maximum likelihood estimation of the proposed Sarmanov distribution is discussed. We present a numerical study using a real data set from a Spanish insurance portfolio.
New Analytical Model Used in Finite Element Analysis of Solids Mechanics
Authors: Vlase Sorin , Nicolescu Adrian , Marin Marin
Published: August 2020

In classical mechanics, determining the governing equations of motion using finite element analysis (FEA) of an elastic multibody system (MBS) leads to a system of second order differential equations. To integrate this, it must be transformed into a system of first-order equations. However, this can also be achieved directly and naturally if Hamilton’s equations are used. The paper presents this useful alternative formalism used in conjunction with the finite element method for MBSs. The motion equations in the very general case of a three-dimensional motion of an elastic solid are obtained. To illustrate the method, two examples are presented. A comparison between the integration times in the two cases presents another possible advantage of applying this method.