bluuebunny/crossref_metadata_2025_split huggingface dataset:
Negotiating (dis-)engagement in K-12 blended learning
Authors: Bergdahl Nina , Bond Melissa 
Published: August 2021

AbstractIt is well-recognised that engagement is critical for learning and school success. Engagement (and disengagement) are, however, also influenced by context. Thus, as digital technologies add complexity to the educational context, they influence classroom leadership, lesson designs and related practices, and thereby engagement. Despite being critical, engagement and disengagement are not well explored concerning these influences, with a lack of research undertaken within socially disadvantaged schools. In this qualitative study, 14 classroom observations were conducted, during five months, in twelve classes in an upper secondary school in Sweden, along with dialogues with teachers (n=12) and students (n=32). The data were analysed using thematic analysis and descriptive statistics. Identified themes include digital context, teacher leadership, engagement and disengagement. A network of relations between the (dis-)engagement compound and themes is presented. The results identified processes in which engagement shifted into disengagement and vice versa; in particular, that the intention of active learning does not automatically translate to active learning for all students, although teachers employed a higher work pace than did their students. Teacher self-efficacy and awareness of how to manage digital technologies in and outside the classroom was found to play a vital role in facilitating engagement. Understanding the (dis-)engagement compound in blended learning environments is key to inform active and visible learning for future research and supportive organisational structures.
Enhancement of root architecture and nitrate transporter gene expression improves plant growth and nitrogen uptake under long-term low-nitrogen stress in barley (Hordeum vulgare L.) seedlings
Authors: Gao Runhong , Guo Guimei , Xu Hongwei , Chen Zhiwei , Li Yingbo , Lu Ruiju , Liu Chenghong , Chen Jianmin 
Published: August 2021

AbstractOver application of nitrogen (N) fertilizers to crops ultimately causes N pollution in the ecosphere. Studying the response of plant growth and N uptake to low-N stress may aid in elucidating the mechanism of low N tolerance in plants and developing crop cultivars with high nitrogen use efficiency (NUE). In this study, a high-NUE mutant line A9-29 and the wild-type barley cultivar Hua30 were subjected to hydroponic culture with high and low N supply, and the dry weight, N accumulation, root morphology, and expression levels of the potential genes involved in nitrate uptake and assimilation were measured at seedling stage. The results showed that under low-N conditions, A9-29 had a higher dry weight, N content, N influx rate and larger root uptake area than did Hua30. Under long-term low-N stress, compared with Hua30, A9-29 demonstrated higher expression of the HvNRT2/3 genes, especially HvNRT2.1, HvNRT2.5, and HvNRT3.3. Similarly, the expression levels of N assimilation genes including HvNIA1, HvNIR1, HvGS1_1, HvGS1_3, and HvGLU2 increased significantly in A9-29. Taken together, our results suggested that the larger root area and the upregulation of nitrate transporter and assimilation genes may contribute to stronger N uptake capacity for plant growth and N accumulation in responding to long-term low-N stress. These findings may aid in understanding the mechanism of low N tolerance and developing barley cultivars with high-NUE.
Authenticity work in higher education learning environments: a double-edged sword?
Authors: Hagvall Svensson Oskar , Adawi Tom , Johansson Anders 
Published: August 2021

AbstractEducational authenticity occupies a strong position in higher education research and reform, building on the assumption that correspondence between higher education learning environments and professional settings is a driver of student engagement and transfer of knowledge beyond academia. In this paper, we draw attention to an overlooked aspect of authenticity, namely the rhetorical work teachers engage in to establish their learning environments as authentic and pedagogically appropriate. We use the term “authenticity work” to denote such rhetorical work. Drawing on ethnography and critical discourse analysis, we describe how two teachers engaged in authenticity work through renegotiating professional and educational discourse in their project-based engineering course. This ideological project was facilitated by three discursive strategies: (1) deficitization of students and academia, (2) naturalization of industry practices, and (3) polarization of the state of affairs in academia and in industry. Our findings suggest that authenticity work is a double-edged sword: While authenticity work may serve to bolster the legitimacy that is ascribed to learning environments, it may also close down opportunities for students to develop critical thinking about their profession and their education. Based on these findings, we discuss implications for teaching and propose a nascent research agenda for authenticity work in higher education learning environments.
Modern Colonialism and Cultural Continuity Through Material Culture: An Example from Guam and CHamoru Plaiting
Authors: Montón-Subías Sandra , Hernando Gonzalo Almudena 
Published: August 2021

AbstractThis article analyzes cultural persistence in Guam through plaiting, material culture, and maintenance activities, a set of daily practices that are essential to social continuity and well-being. The colonization of Guam began in 1668 with the Jesuit missions. Jesuit policies utilized maintenance activities to colonize Indigenous lifeways and subjectivities, but we believe those activities also functioned as reservoirs of traditional knowledge. Although plaiting has been situated in different historical contexts across the centuries, it no doubt expresses material continuities stretching from a precolonial past. The article also challenges today’s widespread belief that the search for change is a universal value. It argues that societies appreciate continuity over change in inverse proportion to technological control over nature, asymmetrical relationships of power, and specialized fragmentation of functional tasks. In the absence of such features, the best guarantee of survival lies in maintaining the balance achieved by traditional lifeways.
Distilling the Requirements of Gödel’s Incompleteness Theorems with a Proof Assistant
Authors: Popescu Andrei , Traytel Dmitriy 
Published: August 2021

AbstractWe present an abstract development of Gödel’s incompleteness theorems, performed with the help of the Isabelle/HOL proof assistant. We analyze sufficient conditions for the applicability of our theorems to a partially specified logic. In addition to the usual benefits of generality, our abstract perspective enables a comparison between alternative approaches from the literature. These include Rosser’s variation of the first theorem, Jeroslow’s variation of the second theorem, and the Świerczkowski–Paulson semantics-based approach. As part of the validation of our framework, we upgrade Paulson’s Isabelle proof to produce a mechanization of the second theorem that does not assume soundness in the standard model, and in fact does not rely on any notion of model or semantic interpretation.
Fabrication and characterization of an antibacterial chitosan/silk fibroin electrospun nanofiber loaded with a cationic peptide for wound-dressing application
Authors: Khosravimelal Sadjad , Chizari Milad , Farhadihosseinabadi Behrouz , Moosazadeh Moghaddam Mehrdad , Gholipourmalekabadi Mazaher 
Published: August 2021

AbstractWound infections are still problematic in many cases and demand new alternatives for current treatment strategies. In recent years, biomaterials-based wound dressings have received much attention due to their potentials and many studies have been performed based on them. Accordingly, in this study, we fabricated and optimized an antibacterial chitosan/silk fibroin (CS/SF) electrospun nanofiber bilayer containing different concentrations of a cationic antimicrobial peptide (AMP) for wound dressing applications. The fabricated CS/SF nanofiber was fully characterized and compared to the electrospun silk fibroin and electrospun chitosan alone in vitro. Then, the release rate of different concentrations of peptide (16, 32, and 64 µg/ml) from peptide-loaded CS/SF nanofiber was investigated. Finally, based on cytotoxic activity, the antibacterial activity of scaffolds containing 16 and 32 µg/ml of the peptide was evaluated against standard and multi-drug resistant strains of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa isolated from burn patients. The peptide-loaded CS/SF nanofiber displayed appropriate mechanical properties, high water uptake, suitable biodegradation rate, a controlled release without cytotoxicity on Hu02 human foreskin fibroblast cells at the 16 and 32 µg/ml concentrations of peptide. The optimized CS/SF containing 32 μg/ml peptide showed strong antibacterial activity against all experimental strains from standard to resistance. The results showed that the fabricated antimicrobial nanofiber has the potential to be applied as a wound dressing for infected wound healing, although further studies are needed in vivo.
Electrospun nano-fibrous bilayer scaffold prepared from polycaprolactone/gelatin and bioactive glass for bone tissue engineering
Authors: Elkhouly Hend , Mamdouh Wael , El-Korashy Dalia I. 
Published: August 2021

AbstractThis work is focused on integrating nanotechnology with bone tissue engineering (BTE) to fabricate a bilayer scaffold with enhanced biological, physical and mechanical properties, using polycaprolactone (PCL) and gelatin (Gt) as the base nanofibrous layer, followed by the deposition of a bioactive glass (BG) nanofibrous layer via the electrospinning technique. Electrospun scaffolds were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy. Surface area and porosity were evaluated using the nitrogen adsorption method and mercury intrusion porosimetry. Moreover, scaffold swelling rate, degradation rate and in vitro bioactivity were examined in simulated body fluid (SBF) for up to 14 days. Mechanical properties of the prepared scaffolds were evaluated. Cell cytotoxicity was assessed using MRC-5 cells. Analyses showed successful formation of bead-free uniform fibers and the incorporation of BG nanoparticles within fibers. The bilayer scaffold showed enhanced surface area and total pore volume in comparison to the composite single layer scaffold. Moreover, a hydroxyapatite-like layer with a Ca/P molar ratio of 1.4 was formed after 14 days of immersion in SBF. Furthermore, its swelling and degradation rates were significantly higher than those of pure PCL scaffold. The bilayer’s tensile strength was four times higher than that of PCL/Gt scaffold with greatly enhanced elongation. Cytotoxicity test revealed the bilayer’s biocompatibility. Overall analyses showed that the incorporation of BG within a bilayer scaffold enhances the scaffold’s properties in comparison to those of a composite single layer scaffold, and offers potential avenues for development in the field of BTE.
In vitro and in vivo biological performance of hydroxyapatite from fish waste
Authors: Prado João Paulo dos Santos , Yamamura Hirochi , Magri Angela Maria Paiva , Ruiz Pedro Luiz Muniz , Prado José Lucas dos Santos , Rennó Ana Claudia Muniz , Ribeiro Daniel Araki , Granito Renata Neves 
Published: August 2021

AbstractThe aim of this study was to evaluate biocompatibility of hydroxyapatite (HAP) from fish waste using in vitro and in vivo assays. Fish samples (whitemouth croaker - Micropogonias furnieri) from the biowaste was used as HAP source. Pre-osteoblastic MC3T3-E1 cells were used in vitro study. In addition, bone defects were artificially created in rat calvaria and filled with HAP in vivo. The results demonstrated that HAP reduced cytotoxicity in pre-osteoblast cells after 3 and 6 days following HAP exposure. DNA concentration was lower in the HAP group after 6 days. Quantitative RT-PCR did not show any significant differences (p > 0.05) between groups. In vivo study revealed that bone defects filled with HAP pointed out moderate chronic inflammatory cells with slight proliferation of blood vessels after 7 and 15 days. Chronic inflammatory infiltrate was absent after 30 days of HAP exposure. There was also a decrease in the amount of biomaterial, being followed by newly formed bone tissue. All experimental groups also demonstrated strong RUNX-2 immoexpression in the granulation tissue as well as in cells in close contact with biomaterial. The number of osteoblasts inside the defect area was lower in the HAP group when compared to control group after 7 days post-implantation. Similarly, the osteoblast surface as well as the percentage of bone surface was higher in control group when compared with HAP group after 7 days post-implantation. Taken together, HAP from fish waste is a promising possibility that should be explored more carefully by tissue-engineering or biotechnology.
Surface properties of a new lithium disilicate glass-ceramic after grinding
Authors: Miotto Larissa Natiele , Villas-Bôas Mariana de Oliveira Carlos , Zanotto Edgar Dutra , Ferreira Eduardo Bellini , Fais Laiza Maria Grassi , Pinelli Lígia Antunes Pereira 
Published: August 2021

AbstractThis study aimed to evaluate the effect of grinding on some surface properties of two lithium disilicate-based glass-ceramics, one experimental new product denominated LaMaV Press (UFSCar-Brazil) and another commercial known as IPS e-max Press (Ivoclar), in the context of simulated clinical adjustment. Discs (N = 24, 12 mm in diameter) were separated into four groups: LaMaV Press with no grinding (E), LaMaV Press after grinding (EG), IPS e-max Press with no grinding (C), and IPS e-max Press after grinding (CG). A 0.1-mm deep grinding was carried out on EG and CG samples (final thickness of 1.4 mm) using a diamond stone in a low-speed device. The E and C samples had the same thickness. The effect of grinding on the sample surfaces was evaluated by X-ray diffraction, mechanical and optical profilometry, scanning electron microscopy, goniometry, and Vickers hardness. The mean roughness (Ra) was evaluated by Kruskal–Wallis and Student–Newman–Keuls statistics. The surface energy (SE) by the sessile drop method and Vickers hardness (VH) were analyzed using two-way ANOVA. The Ra medians were E = 1.69 µm, EG = 1.57 µm, C = 1.45 µm, and CG = 1.13 µm with p = 0.0284. The SE and VH were similar for all materials and treatments. Grinding smoothed the surfaces and did not significantly alter the hardness and surface energy of both LaMaV Press and IPS e-max Press. These glass-ceramics presented similar surface properties, and clinical adjustments can be implemented without loss of performance of both materials.
Polyethylene glycol triggers the anti-cancer impact of curcumin nanoparticles in sw-1736 thyroid cancer cells
Authors: Hosseinzadeh Simzar , Nazari Hojjatollah , Esmaeili Elaheh , Hatamie Shadie 
Published: August 2021

AbstractCurcumin has been recognized as an effective anticancer agent. However, due to its hydrophobic property, the cell absorption is not satisfied. Herein, the curcumin nanoparticles were prepared in the presence of polyethylene glycol 6000 (PEG6000) to reduce its elimination by immune system. For first time, not only the curcumin was encapsulated within the niosome nanoparticles modified by PEG, there are no reports related to the anticancer property of curcumin against thyroid cancers. The nanoparticles was developed and its anticancer was studied on sw-1736 cancer cell line. The nanoparticles were examined by scanning electron microscopy (SEM) and dynamic light scattering (DLS). Also, the release profile of curcumin, the IC50 concentration, the radical amount and the gene expression were evaluated. The optimized nanoparticles showed a diameter of 212 ± 31 nm by SEM and the encapsulation efficiency and loading capacity of 76% and 16.8% respectively. DLS confirmed the polydispersity index (PDI) of 0.596 and the release model was shown a sustained release with the delivery of 68% curcumin after 6 days. Also, the nanoparticles indicated the higher storage stability at 4 °C. After the cell treatment, the apoptotic bodies were appeared and IC50 was obtained as 0.159 mM. Moreover, the generated radicals by the treated cells was 86% after 72 h and the gene pattern indicated the bax/bcl2 ratio of 6.83 confirming the apoptosis effect of the nanoparticles. The results approved the nanoparticles could be suggested as an anticancer drug candidate for thyroid cancers.
Hidden invariant convexity for global and conic-intersection optimality guarantees in discrete-time optimal control
Authors: Baayen Jorn H. , Postek Krzysztof 
Published: August 2021

AbstractNon-convex discrete-time optimal control problems in, e.g., water or power systems, typically involve a large number of variables related through nonlinear equality constraints. The ideal goal is to find a globally optimal solution, and numerical experience indicates that algorithms aiming for Karush–Kuhn–Tucker points often find solutions that are indistinguishable from global optima. In our paper, we provide a theoretical underpinning for this phenomenon, showing that on a broad class of problems the objective can be shown to be an invariant convex function (invex function) of the control decision variables when state variables are eliminated using implicit function theory. In this way, optimality guarantees can be obtained, the exact nature of which depends on the position of the solution within the feasible set. In a numerical example, we show how high-quality solutions are obtained with local search for a river control problem where invexity holds.
Evaluation of mesostructured silica materials with different structures and morphologies as carriers for quercetin and naringin encapsulation
Authors: Morante-Zarcero Sonia , Endrino Alba , Casado Natalia , Pérez-Quintanilla Damián , Sierra Isabel 
Published: August 2021

AbstractTwo mesostructured silicas with wormhole-like pore arrangement (HMS and MSU-2) were synthesized and evaluated for the first time as carriers for the encapsulation of two bioactive flavonoids (quercetin and naringin). For comparative purposes, a hexagonal mesostructured SBA-15 silica type frequently used as encapsulating support was also prepared and tested. All the materials were characterized before and after the loading with the analytes. Different silica/analyte ratios were evaluated to determine the loading and encapsulation kinetics of the different materials. Both flavonoids were successfully loaded inside the pores of the three silicas. The quercetin loading capacity of HMS was higher than SBA-15 and MSU-2 silicas, whereas for naringin SBA-15 and MSU-2 were slightly more effective. These differences could be attributed to the molecular size of the analytes and the textural properties of the different materials. Nevertheless, HMS was the silica that enabled to release the highest amount of both analytes. Thus, it could be considered a suitable carrier of these flavonoids and an alternative to other materials such as SBA-15. Moreover, the release process was performed under controlled conditions (pH 2.0 and 7.4) to simulate digestive conditions. Quercetin was delivered faster and more efficiently from the encapsulated at pH 2.0, whereas no differences were observed for naringin at both pHs. Finally, the antioxidant activity of the resulting encapsulates was determined. The results obtained suggested the potential use of wormhole-like mesostructured silicas as carriers to enhance the stability and bioavailability of flavonoids, so they can be used in future food and biomedical applications.
Verifying Negative Sentences
Authors: Wang Shenshen , Sun Chao , Tian Ye , Breheny Richard 
Published: August 2021

AbstractIn the long history of psycholinguistic research on verifying negative sentences, an often-reported finding is that participants take longer to correctly judge negative sentences true than false, while being faster to judge their positive counterparts true (e.g. Clark & Chase, Cogn Psychol 3(3):472−517, 1972; Carpenter & Just, Psychol Rev 82(1):45–73, 1975). While many linguists and psycholinguists have strongly advocated the idea that the costs and complexity of negation can be explained by appeal to context, context-based approaches have not been able to provide a satisfying account of this polarity*truth-value interaction. By contrast, the alternative theory of negation processing, which says that negation is processed by separately representing the positive, does provide a plausible account. Our proposals provide a means for reconciliation between the two views since we argue that negation is a strong cue to a positive context. Here we present our account of why and when negation is often apparently processed via the positive. We review many of the factors that are seen to be at play in sentence verification involving negation. We present evidence that participants’ adoption of the positive-first procedure in sentence-picture verification tasks is conditioned by context.
Translation and Validation of the Spanish Version of the Spiritual Care Competence Questionnaire (SCCQ)
Authors: Pastrana Tania , Frick Eckhard , Krikorian Alicia , Ascencio Leticia , Galeazzi Florencia , Büssing Arndt 
Published: August 2021

AbstractWe aimed to validate the Spanish version of the Spiritual Care Competence Questionnaire (SCCQ) in a sample of 791 health care professionals from Spanish speaking countries coming principally from Argentina, Colombia, Mexico and Spain. Exploratory factor analysis pointed to six factors with good internal consistency (Cronbach’s alpha ranging from 0.71 to 0.90), which are in line with the factors of the primary version of the SCCQ. Conversation competences and Perception of spiritual needs competences scored highest, and Documentation competences and Team spirit the lowest, Empowerment competences and Spiritual self-awareness competences in-between. The Spanish Version of the SCCQ can be used for assessment of spiritual care competencies, planning of educational activities and for comparisons as well as monitoring/follow-up after implementation of improvement strategies.