bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamic Evolution and Spatial Convergence of the Virtual Cultivated Land Flow Intensity in China
Authors: Wang Kunpeng , Wu Wenjun , Jabbar Awais , Wolde Zinabu , Ou Minghao
Published: July 2021

Exploring the flow intensity of virtual cultivated land is the key to improving the ecological compensation and food security policy. This study aimed to analyze the dynamic evolution, spatial convergence, and its affecting factors of the virtual cultivated land flow intensity. The spatial convergence model was used in this study. The results showed that, during 2000–2018, the growth rate of the surplus state of virtual cultivated land at the national level is less than that of the deficit state of virtual cultivated land in China. Moreover, the number of deficit provinces of virtual cultivated land flow intensity is increasing. The absolute β-convergence characteristics of the virtual cultivated land flow intensity are significant at the national, northeast, central, and western regions. Additionally, the conditional β-convergence exists at the national and four regional levels. Meanwhile, cultivated land resource endowment, population scale, regional economic development level, and agricultural mechanization level play an important role in the convergence process of inter-regional virtual cultivated land flow intensity. However, the influence degree of different control variables on different regional virtual cultivated land flow intensity is not consistent. Therefore, policymakers should pay attention to cultivated land resources’ spatial transfer mechanism when making regional cultivated land ecological compensation policies to coordinate the interesting relationship between the deficit area and surplus area of virtual cultivated land. Therefore, it is necessary to take the virtual cultivated land flow intensity as the reference index and use the combination of market guidance and government control to stimulus the stakeholders to protect cultivated land by taking different measures.
Operationalizing Social Environments in Cognitive Aging and Dementia Research: A Scoping Review
Authors: Peterson Rachel L. , George Kristen M. , Tran Duyen , Malladi Pallavi , Gilsanz Paola , Kind Amy J. H. , Whitmer Rachel A. , Besser Lilah M. , Meyer Oanh L.
Published: July 2021

Background: Social environments are a contributing determinant of health and disparities. This scoping review details how social environments have been operationalized in observational studies of cognitive aging and dementia. Methods: A systematic search in PubMed and Web of Science identified studies of social environment exposures and late-life cognition/dementia outcomes. Data were extracted on (1) study design; (2) population; (3) social environment(s); (4) cognitive outcome(s); (5) analytic approach; and (6) theorized causal pathways. Studies were organized using a 3-tiered social ecological model at interpersonal, community, or policy levels. Results: Of 7802 non-duplicated articles, 123 studies met inclusion criteria. Eighty-four studies were longitudinal (range 1–28 years) and 16 examined time-varying social environments. When sorted into social ecological levels, 91 studies examined the interpersonal level; 37 examined the community/neighborhood level; 3 examined policy level social environments; and 7 studies examined more than one level. Conclusions: Most studies of social environments and cognitive aging and dementia examined interpersonal factors measured at a single point in time. Few assessed time-varying social environmental factors or considered multiple social ecological levels. Future studies can help clarify opportunities for intervention by delineating if, when, and how social environments shape late-life cognitive aging and dementia outcomes.
Optogenetic Manipulation of Olfactory Responses in Transgenic Zebrafish: A Neurobiological and Behavioral Study
Authors: Jeong Yun-Mi , Choi Tae-Ik , Hwang Kyu-Seok , Lee Jeong-Soo , Gerlai Robert , Kim Cheol-Hee
Published: July 2021

Olfaction is an important neural system for survival and fundamental behaviors such as predator avoidance, food finding, memory formation, reproduction, and social communication. However, the neural circuits and pathways associated with the olfactory system in various behaviors are not fully understood. Recent advances in optogenetics, high-resolution in vivo imaging, and reconstructions of neuronal circuits have created new opportunities to understand such neural circuits. Here, we generated a transgenic zebrafish to manipulate olfactory signal optically, expressing the Channelrhodopsin (ChR2) under the control of the olfactory specific promoter, omp. We observed light-induced neuronal activity of olfactory system in the transgenic fish by examining c-fos expression, and a calcium indicator suggesting that blue light stimulation caused activation of olfactory neurons in a non-invasive manner. To examine whether the photo-activation of olfactory sensory neurons affect behavior of zebrafish larvae, we devised a behavioral choice paradigm and tested how zebrafish larvae choose between two conflicting sensory cues, an aversive odor or the naturally preferred phototaxis. We found that when the conflicting cues (the preferred light and aversive odor) were presented together simultaneously, zebrafish larvae swam away from the aversive odor. However, the transgenic fish with photo-activation were insensitive to the aversive odor and exhibited olfactory desensitization upon optical stimulation of ChR2. These results show that an aversive olfactory stimulus can override phototaxis, and that olfaction is important in decision making in zebrafish. This new transgenic model will be useful for the analysis of olfaction related behaviors and for the dissection of underlying neural circuits.
Systematic Understanding of Recent Developments in Bacterial Cellulose Biosynthesis at Genetic, Bioprocess and Product Levels
Authors: Buldum Gizem , Mantalaris Athanasios
Published: July 2021

Engineering biological processes has become a standard approach to produce various commercially valuable chemicals, therapeutics, and biomaterials. Among these products, bacterial cellulose represents major advances to biomedical and healthcare applications. In comparison to properties of plant cellulose, bacterial cellulose (BC) shows distinctive characteristics such as a high purity, high water retention, and biocompatibility. However, low product yield and extensive cultivation times have been the main challenges in the large-scale production of BC. For decades, studies focused on optimization of cellulose production through modification of culturing strategies and conditions. With an increasing demand for BC, researchers are now exploring to improve BC production and functionality at different categories: genetic, bioprocess, and product levels as well as model driven approaches targeting each of these categories. This comprehensive review discusses the progress in BC platforms categorizing the most recent advancements under different research focuses and provides systematic understanding of the progress in BC biosynthesis. The aim of this review is to present the potential of ‘modern genetic engineering tools’ and ‘model-driven approaches’ on improving the yield of BC, altering the properties, and adding new functionality. We also provide insights for the future perspectives and potential approaches to promote BC use in biomedical applications.
Decreased Glucocorticoid Signaling Potentiates Lipid-Induced Inflammation and Contributes to Insulin Resistance in the Skeletal Muscle of Fructose-Fed Male Rats Exposed to Stress
Authors: Shirif Abdulbaset Zidane , Kovačević Sanja , Brkljačić Jelena , Teofilović Ana , Elaković Ivana , Djordjevic Ana , Matić Gordana
Published: July 2021

The modern lifestyle brings both excessive fructose consumption and daily exposure to stress which could lead to metabolic disturbances and type 2 diabetes. Muscles are important points of glucose and lipid metabolism, with a crucial role in the maintenance of systemic energy homeostasis. We investigated whether 9-week fructose-enriched diet, with and without exposure to 4-week unpredictable stress, disturbs insulin signaling in the skeletal muscle of male rats and evaluated potential contributory roles of muscle lipid metabolism, glucocorticoid signaling and inflammation. The combination of fructose-enriched diet and stress increased peroxisome proliferator-activated receptors-α and -δ and stimulated lipid uptake, lipolysis and β-oxidation in the muscle of fructose-fed stressed rats. Combination of treatment also decreased systemic insulin sensitivity judged by lower R-QUICKI, and lowered muscle protein content and stimulatory phosphorylations of insulin receptor supstrate-1 and Akt, as well as the level of 11β-hydroxysteroid dehydrogenase type 1 and glucocorticoid receptor. At the same time, increased levels of protein tyrosine phosphatase-1B, nuclear factor-κB, tumor necrosis factor-α, were observed in the muscle of fructose-fed stressed rats. Based on these results, we propose that decreased glucocorticoid signaling in the skeletal muscle can make a setting for lipid-induced inflammation and the development of insulin resistance in fructose-fed stressed rats.
Change Point Detection in Terrorism-Related Online Content Using Deep Learning Derived Indicators
Authors: Theodosiadou Ourania , Pantelidou Kyriaki , Bastas Nikolaos , Chatzakou Despoina , Tsikrika Theodora , Vrochidis Stefanos , Kompatsiaris Ioannis
Published: July 2021

Given the increasing occurrence of deviant activities in online platforms, it is of paramount importance to develop methods and tools that allow in-depth analysis and understanding to then develop effective countermeasures. This work proposes a framework towards detecting statistically significant change points in terrorism-related time series, which may indicate the occurrence of events to be paid attention to. These change points may reflect changes in the attitude towards and/or engagement with terrorism-related activities and events, possibly signifying, for instance, an escalation in the radicalization process. In particular, the proposed framework involves: (i) classification of online textual data as terrorism- and hate speech-related, which can be considered as indicators of a potential criminal or terrorist activity; and (ii) change point analysis in the time series generated by these data. The use of change point detection (CPD) algorithms in the produced time series of the aforementioned indicators—either in a univariate or two-dimensional case—can lead to the estimation of statistically significant changes in their structural behavior at certain time locations. To evaluate the proposed framework, we apply it on a publicly available dataset related to jihadist forums. Finally, topic detection on the estimated change points is implemented to further assess its effectiveness.
Duration of Low Temperature Exposure Affects Egg Hatching of the Colorado Potato Beetle and Emergence of Overwintering Adults
Authors: Liao Jianghua , Liu Juan , Guan Zhijian , Li Chao
Published: July 2021

The Colorado potato beetle is a serious pest of Solanaceae in China. In early summer, cold spells in later spring may occur for brief periods in the field environmental conditions, and temperatures often deviate far below the normal temperature for short periods, such as sudden short-term low temperature, may affect the development of Colorado potato beetle eggs. This paper studies the effects of low temperature stress at 8 °C for 0 d, 1 d, 3 d, 5 d, 7 d, and 10 d on the development of Colorado potato beetle eggs. Our results show that egg survival is significantly affected by short-term low temperature exposure. The percentage of eggs hatched is significantly affected by different treatment times (p = 0.000)—the percentage of eggs hatched decreases with increased treatment time, and Colorado potato beetles will extend the wintering time of their soil to resist the effects of lower temperatures. Thus, exposure of Colorado potato beetles to a short-term low temperature affects their emergence and population growth; this study could provide information for the occurrence, monitoring, and early warning of Colorado potato beetle during short-term temperature.
Achieving Ethical Algorithmic Behaviour in the Internet of Things: A Review
Authors: Loke Seng W.
Published: July 2021

The Internet of Things is emerging as a vast, inter-connected space of devices and things surrounding people, many of which are increasingly capable of autonomous action, from automatically sending data to cloud servers for analysis, changing the behaviour of smart objects, to changing the physical environment. A wide range of ethical concerns has arisen in their usage and development in recent years. Such concerns are exacerbated by the increasing autonomy given to connected things. This paper reviews, via examples, the landscape of ethical issues, and some recent approaches to address these issues concerning connected things behaving autonomously as part of the Internet of Things. We consider ethical issues in relation to device operations and accompanying algorithms. Examples of concerns include unsecured consumer devices, data collection with health-related Internet of Things, hackable vehicles, behaviour of autonomous vehicles in dilemma situations, accountability with Internet of Things systems, algorithmic bias, uncontrolled cooperation among things, and automation affecting user choice and control. Current ideas towards addressing a range of ethical concerns are reviewed and compared, including programming ethical behaviour, white-box algorithms, black-box validation, algorithmic social contracts, enveloping IoT systems, and guidelines and code of ethics for IoT developers; a suggestion from the analysis is that a multi-pronged approach could be useful based on the context of operation and deployment.
Eye Tracking—An Innovative Tool in Medical Parasitology
Authors: Kołodziej Przemysław , Tuszyńska-Bogucka Wioletta , Dzieńkowski Mariusz , Bogucki Jacek , Kocki Janusz , Milosz Marek , Kocki Marcin , Reszka Patrycja , Kocki Wojciech , Bogucka-Kocka Anna
Published: July 2021

The innovative Eye Movement Modelling Examples (EMMEs) method can be used in medicine as an educational training tool for the assessment and verification of students and professionals. Our work was intended to analyse the possibility of using eye tracking tools to verify the skills and training of people engaged in laboratory medicine on the example of parasitological diagnostics. Professionally active laboratory diagnosticians working in a multi-profile laboratory (non-parasitological) (n = 16), laboratory diagnosticians no longer working in this profession (n = 10), and medical analyst students (n = 56), participated in the study. The studied group analysed microscopic images of parasitological preparations made with the cellSens Dimension Software (Olympus) system. Eye activity parameters were obtained using a stationary, video-based eye tracker Tobii TX300 which has a 3-ms temporal resolution. Eye movement activity parameters were analysed along with time parameters. The results of our studies have shown that the eye tracking method is a valuable tool for the analysis of parasitological preparations. Detailed quantitative and qualitative analysis confirmed that the EMMEs method may facilitate learning of the correct microscopic image scanning path. The analysis of the results of our studies allows us to conclude that the EMMEs method may be a valuable tool in the preparation of teaching materials in virtual microscopy. These teaching materials generated with the use of eye tracking, prepared by experienced professionals in the field of laboratory medicine, can be used during various training, simulations and courses in medical parasitology and contribute to the verification of education results, professional skills, and elimination of errors in parasitological diagnostics.
Short- and Mid-Term Outcomes in Patients Deemed Inoperable Undergoing Transapical and Transfemoral TAVR with an STS-PROM below Four Percent
Authors: Veulemans Verena , Hellhammer Katharina , Borhan Azad Armin , Goh Shouheng , Drake Christian , Maier Oliver , Piayda Kerstin , Polzin Amin , Mehdiani Arash , Jung Christian , Westenfeld Ralf , Kelm Malte , Lichtenberg Artur , Zeus Tobias
Published: July 2021

Transapical (TA) TAVR is known to be associated with increased mortality and vascular complications compared with transfemoral (TF) TAVR in high-risk and inoperable patients. However, safe alternative access methods remain crucial. We aimed to (1) evaluate the 30-day and 1-year outcomes comparing TA and TF TAVR in patients with an STS-PROM of <4% deemed inoperable and (2) determine dependent and independent predictors for all-cause one-year mortality. Data were collected from a single-center registry consisting of 340 eligible patients. One-to-one propensity score matching was performed (n = 50 TA, n = 50 TF). Primary endpoints were all-cause mortality, stroke, and major bleeding. Predictors for all-cause one-year mortality were evaluated. Thirty-day mortality (TF vs. TA: 0.0% vs. 4.0%; p = 0.153) was comparable in both cohorts. One-year all-cause mortality was twice as high in TA patients (TF vs. TA: 10.0% vs. 20.0%, p logrank = 0.165, HR 2.10). Cerebrovascular events and major bleeding during one-year follow-up were similar. The multivariate analysis identified hemoglobin <12 g/dL at admission and dual antiplatelet therapy as strong predictors for one-year mortality. Although femoral access is the primary access with favorable 30-day and 1-year results, transapical access was successful for patients unsuitable for TF TAVR, showing acceptable short- and mid-term results in inoperable patients with low-risk profiles.
Individual Differences in Attention and Intelligence: A United Cognitive/Psychometric Approach
Authors: Conway Andrew R. A. , Kovacs Kristof , Hao Han , Rosales Kevin P. , Snijder Jean-Paul
Published: July 2021

Process overlap theory (POT) is a new theoretical framework designed to account for the general factor of intelligence (g). According to POT, g does not reflect a general cognitive ability. Instead, g is the result of multiple domain-general executive attention processes and multiple domain-specific processes that are sampled in an overlapping manner across a battery of intelligence tests. POT explains several benchmark findings on human intelligence. However, the precise nature of the executive attention processes underlying g remains unclear. In the current paper, we discuss challenges associated with building a theory of individual differences in attention and intelligence. We argue that the conflation of psychological theories and statistical models, as well as problematic inferences based on latent variables, impedes research progress and prevents theory building. Two studies designed to illustrate the unique features of POT relative to previous approaches are presented. In Study 1, a simulation is presented to illustrate precisely how POT accounts for the relationship between executive attention processes and g. In Study 2, three datasets from previous studies are reanalyzed (N = 243, N = 234, N = 945) and reveal a discrepancy between the POT simulated model and the unity/diversity model of executive function. We suggest that this discrepancy is largely due to methodological problems in previous studies but also reflects different goals of research on individual differences in attention. The unity/diversity model is designed to facilitate research on executive function and dysfunction associated with cognitive and neural development and disease. POT is uniquely suited to guide and facilitate research on individual differences in cognitive ability and the investigation of executive attention processes underlying g.
Ocean Acidification and Direct Interactions Affect Coral, Macroalga, and Sponge Growth in the Florida Keys
Authors: Page Heather N. , Hewett Clay , Tompkins Hayden , Hall Emily R.
Published: July 2021

Coral reef community composition, function, and resilience have been altered by natural and anthropogenic stressors. Future anthropogenic ocean and coastal acidification (together termed “acidification”) may exacerbate this reef degradation. Accurately predicting reef resilience requires an understanding of not only direct impacts of acidification on marine organisms but also indirect effects on species interactions that influence community composition and reef ecosystem functions. In this 28-day experiment, we assessed the effect of acidification on coral–algal, coral–sponge, and algal–sponge interactions. We quantified growth of corals (Siderastrea radians), fleshy macroalgae (Dictyota spp.), and sponges (Pione lampa) that were exposed to local summer ambient (603 μatm) or elevated (1105 μatm) pCO2 seawater. These species are common to hard-bottom communities, including shallow reefs, in the Florida Keys. Each individual was maintained in isolation or paired with another organism. Coral growth (net calcification) was similar across seawater pCO2 and interaction treatments. Fleshy macroalgae had increased biomass when paired with a sponge but lost biomass when growing in isolation or paired with coral. Sponges grew more volumetrically in the elevated seawater pCO2 treatment (i.e., under acidification conditions). Although these results are limited in temporal and spatial scales due to the experimental design, they do lend support to the hypothesis that acidification may facilitate a shift towards increased sponge and macroalgae abundance by directly benefiting sponge growth which in turn may provide more dissolved inorganic nitrogen to macroalgae in the Florida Keys.
Clinical Impact of Pre-Procedural Percutaneous Coronary Intervention in Low- and Intermediate-Risk Transcatheter Aortic Valve Replacement Recipients
Authors: Winter Max-Paul , Hofbauer Thomas M. , Bartko Philipp E. , Nitsche Christian , Koschutnik Matthias , Kammerlander Andreas A. , Donà Carolina , Spinka Georg , Spinka Fabian , Andreas Martin , Mach Markus , Rosenhek Raphael , Lang Irene M. , Mascherbauer Julia , Hengstenberg Christian , Goliasch Georg
Published: July 2021

The clinical relevance of as well as the optimal treatment strategy for coronary artery disease (CAD) in patients undergoing transcatheter aortic valve replacement (TAVR) for severe aortic stenosis (AS) are unclear. Current data are conflicting, and mainly derived from high-risk patients. We aimed to investigate the feasibility and safety of complete revascularization prior to TAVR for severe AS in low- and intermediate-risk patients. We enrolled 449 patients at low (STS score < 4%) and intermediate risk (STS score 4–8%) undergoing TAVR for severe AS and investigated the influence of recent (<3 months) and prior (>3 months) complete revascularization on clinical outcome. Primary study endpoint was all-cause mortality. Overall, 58% of patients had no or non-significant CAD; 18% had a history of complete revascularization prior to TAVR and 24% had complete revascularization shortly before TAVR. Two-year all-cause mortality was not different between patients with recent revascularization prior to TAVR and patients with no or non-significant CAD (13.7% vs. 14.2%, p = 0.905). Cox regression did not reveal an effect on all-cause mortality for recent revascularization. The present analysis reassures that percutaneous complete revascularization prior to TAVR procedures is neutral in terms of all-cause mortality in patients at low and intermediate surgical risk.
Somatic Tumor Profile Analysis in a Patient with Germline PMS2 Mutation and Synchronous Ovarian and Uterine Carcinomas
Authors: Huelsman Karen M. , Basil Jack B. , Sisson Rebecca , Lipe Lindsay R. , Mahon Brett , Draper David J.
Published: July 2021

Lynch syndrome patients with synchronous endometrial and ovarian cancer (SEOC) are rare. When these cases occur, they are most often endometrioid histology and early grade. Early-grade tumors are not often sent for somatic tumor profiling. We present a 39 year old SEOC patient with germline PMS2 Lynch syndrome and clinical tumor analysis leading to insight regarding the origin and cause of these tumors, with potential therapy options. PMS2-related SEOC is less common due to lower risks for these cancers associated with germline PMS2 mutation compared to other Lynch genes. While synchronous cancers are not common, they are more likely to occur with Lynch syndrome. Tumor profiling with next-generation sequencing of 648 genes identified sixteen shared somatic actionable and biologically relevant mutations. This case is a rare example of a patient with PMS2 germline Lynch syndrome with shared somatic variants that demonstrate clonality of the two tumors arising from one common site.
Revisited: Monopoly and Long-Run Capital Accumulation in Two-Sector Overlapping Generation Model
Authors: Kumar Ronald Ravinesh , Stauvermann Peter J.
Published: July 2021

In this paper, we investigate if an increasing competition in an oligopolistic market will enhance the real incomes and consumer surplus in the long run. For this purpose, we apply a two-sector overlapping generation model in which members of the young generation own the oligopolistic firms. We show that increasing competition in the oligopolistic market leads to ambiguous outcomes regarding the real income and consumer surplus in the long run. However, we show that the distribution of income will become fairer if the competition increases, but it is possible that the price for a fairer distribution is a lower income for all members of the economy.
Spatiotemporal Changes of Land Ecological Security and Its Obstacle Indicators Diagnosis in the Beijing–Tianjin–Hebei Region
Authors: Guo Dongyan , Wang Dongyan , Zhong Xiaoyong , Yang Yuanyuan , Jiang Lixin
Published: July 2021

Land ecological security (LES) is a cornerstone of sustainable development, and the study of the LES evaluation has become a hot field in the LES problems. The coordinated development of the Beijing–Tianjin–Hebei (BTH) region is one of China’s national development strategies. With the development of urbanization and industrialization, the conflicts between people and land in this area are increasingly prominent, and there are large regional differences in land ecological quality. To evaluate the land ecological security (LES) of this region, an evaluation index system is constructed based on the pressure–state–response (PSR) framework model, and the entropy-weighted TOPSIS method is applied to calculate the LES index. Then, the spatio-temporal changes of LES in the BTH region from 2007 to 2018 are analyzed. In addition, we adopt an obstacle degree model to analyze the obstacle indicators. The results show that the LES of the BTH region increased from 0.1934 to 0.3284 during 2007–2018, and the LES level increased from the dangerous level (I) to the critical level (III). Despite the improved LES in all areas in the BTH region, there were different trends (high in the central area, relatively low in the northern and southern areas). We identified seven obstacle indicators and discussed different development strategies. Our findings will provide guidelines for land use management and offer references for the coordinated development of the BTH region.
On Blockchain Integration with Supply Chain: Overview on Data Transparency
Authors: Hellani Houssein , Sliman Layth , Samhat Abed Ellatif , Exposito Ernesto
Published: July 2021

Data transparency is essential in the modern supply chain to improve trust and boost collaboration among partners. In this context, Blockchain is a promising technology to provide full transparency across the entire supply chain. However, Blockchain was originally designed to provide full transparency and uncontrolled data access. This leads many market actors to avoid Blockchain as they fear for their confidentiality. In this paper, we highlight the requirements and challenges of supply chain transparency. We then investigate a set of supply chain projects that tackle data transparency issues by utilizing Blockchain in their core platform in different manners. Furthermore, we analyze the projects’ techniques and the tools utilized to customize transparency. As a result of the projects’ analyses, we identified that further enhancements are needed to set a balance between the data transparency and process opacity required by different partners, to ensure the confidentiality of their processes and to control access to sensitive data.
Policy Implications on Transport Infrastructure–Trade Dynamics: Case of Turkey
Authors: Şahan Duygu , Tuna Okan
Published: July 2021

Transportation has a mediating position in international trade formation and in the past few decades, Turkey has invested substantially in transport infrastructure to increase connectivity and integration in global transport networks. Still, limited research has been conducted to understand channels and scope of the transport infrastructure development impacts on foreign trade. The objective of this study is to evaluate short-run and long-run causal linkages between transport infrastructure, exports and imports in Turkey for the period between 1987–2019. An autoregressive distributed lag (ARDL) model is developed considering road and rail transport infrastructure components as well as information and communication technology (ICT) infrastructure as a complement to quality transport networks. Results suggest that a speedy road network serves as a locomotive in trade development whereas rail infrastructure can be beneficial if a holistic connectivity plan is developed in a long-term perspective to improve multimodal transportation under a comprehensive, sustained transport policy. Besides, benefits of transport infrastructure investment can be realized in favor of export promotion rather than import growth if a comprehensive policy is followed. In that way transport infrastructure investment would become a stronger instrument to accomplish export competitiveness.
Safety Comes First: Novel Styrene Butadiene Rubber (SBR) and Ethylene Propylene Diene Monomer (EPDM) Surfaces as a Response to Sport Injuries
Authors: Strąk Cezary , Małek Marcin , Jackowski Mateusz , Sudoł Ewa
Published: July 2021

An athlete’s performance depends not only on the shoes they wear but also on the surface used in sports facilities. In addition, it can significantly contribute to reducing injuries, which are easy to get during sports competitions. In the present study, we wanted to investigate whether recycled styrene butadiene rubber (SBR) and ethylene propylene diene monomer (EPDM) could be used in the production of sports surfaces. For this purpose, we designed three different sports surfaces: (1) SBR covered with a thin EPDM spray layer on the top, (2) clean EPDM, and (3) bottom SBR layer with the top layer of EPDM. The test program of these surfaces included in its scope: shock absorption, vertical deformation, tensile strength, abrasion resistance, and slip resistance tests. Our research also involved the influence of the substrate under surface, temperature, and surface conditions. Presented results show that both materials, in the right proportions, can be used in the production of sports surfaces.
A Textile Waste Fiber-Reinforced Cement Composite: Comparison between Short Random Fiber and Textile Reinforcement
Authors: Sadrolodabaee Payam , Claramunt Josep , Ardanuy Mònica , de la Fuente Albert
Published: July 2021

Currently, millions of tons of textile waste from the garment and textile industries are generated worldwide each year. As a promising option in terms of sustainability, textile waste fibers could be used as internal reinforcement of cement-based composites by enhancing ductility and decreasing crack propagation. To this end, two extensive experimental programs were carried out, involving the use of either fractions of short random fibers at 6–10% by weight or nonwoven fabrics in 3–7 laminate layers in the textile waste-reinforcement of cement, and the mechanical and durability properties of the resulting composites were characterized. Flexural resistance in pre- and post-crack, toughness, and stiffness of the resulting composites were assessed in addition to unrestrained drying shrinkage testing. The results obtained from those programs were analyzed and compared to identify the optimal composite and potential applications. Based on the results of experimental analysis, the feasibility of using this textile waste composite as a potential construction material in nonstructural concrete structures such as facade cladding, raised floors, and pavements was confirmed. The optimal composite was proven to be the one reinforced with six layers of nonwoven fabric, with a flexural strength of 15.5 MPa and a toughness of 9.7 kJ/m2.
Effect of Bioactive Glass-Containing Light-Curing Varnish on Enamel Remineralization
Authors: Kim Hyun-Jung , Mo So-Yeon , Kim Duck-Su
Published: July 2021

This study aimed to evaluate the effect of novel experimental light-curing bioactive glass (BAG)-containing varnish on enamel remineralization. An experimental light-curing, BAG-containing varnish and two commercial varnishes (Nupro White Varnish; Dentsply International, York, PA, USA and Tooth Mousse; GC Corporation, Tokyo, Japan) were used. Microhardness tests (n = 3), field emission scanning electron microscopy (FE-SEM) coupled with energy dispersive X-ray spectroscopy (EDS) (n = 5), and X-ray diffraction (XRD) analysis (n = 5) were performed to compare the remineralization effect of three varnishes with and without ultrasonication. The data of microhardness test were analyzed using one-way ANOVA and Tukey’s post hoc comparison (P < 0.05). Microhardness of demineralized enamel increased after the application of three varnishes (P < 0.05). The experimental BAG-containing varnish showed the highest microhardness among the three varnishes (P < 0.05). Ultrasonication decreased microhardness of Tooth Mousse and BAG-containing varnish groups (P < 0.05). FE-SEM and XRD revealed precipitates of hydroxyapatite (HAP) or fluorapatite (FAP) crystals of three varnishes. The novel experimental BAG-containing varnish may be a promising clinical strategy for the remineralization of early carious lesions or demineralized enamel surfaces.
SIAM—Colombia MMC: A Challenge-Based Math Modeling Learning Strategy
Authors: Méndez-Romero Rafael Alberto , Bueno-Carreño Diana H. , Díez-Fonnegra Carlos , Redondo Johan Manuel
Published: July 2021

The math modeling challenge CoSIAM is a competition based on interdisciplinary collaborative work challenges. This research seeks to demonstrate the value of this type of challenge-based competition as a learning strategy outside the classroom. Based on data, we conducted a qualitative study on the perception of the participants in the last three versions of the mathematical modeling challenge, in terms of the learning achieved, the benefits of their participation, the knowledge and skills they brought into play, and the change in their conception of modeling. The participants were undergraduate and graduate students in mathematics and other areas, from several Colombian and Mexican universities. The research yielded results in three directions. The first is related to the advantages and limitations of teamwork, the second explores the learning that arises from this experience, and the third is oriented to the disciplinary knowledge mobilized for the solution of this type of problematic situation. The study allowed concluding, among other issues, that learning based on interdisciplinary problem solving, formulated from a global perspective, enhances the acquisition of valuable skills for the participants.
A Tool for the Analysis and Characterization of School Mathematical Models
Authors: Montejo-Gámez Jesús , Fernández-Ahumada Elvira , Adamuz-Povedano Natividad
Published: July 2021

This paper shows a tool for the analysis of written productions that allows for the characterization of the mathematical models that students develop when solving modeling tasks. For this purpose, different conceptualizations of mathematical models in education are discussed, paying special attention to the evidence that characterizes a school model. The discussion leads to the consideration of three components, which constitute the main categories of the proposed tool: the real system to be modeled, its mathematization and the representations used to express both. These categories and the corresponding analysis procedure are explained and illustrated through two working examples, which expose the value of the tool in establishing the foci of analysis when investigating school models, and thus, suggest modeling skills. The connection of this tool with other approaches to educational research on mathematical modeling is also discussed.
Numerical Modelling and Simulation Applied to Head Trauma
Authors: Fernandes Fábio A. O. , Ptak Mariusz
Published: July 2021

Traumatic brain injury (TBI) is one of the leading causes of death and disability [...]
A Complementary and Revised View on the N-Acylation of Chitosan with Hexanoyl Chloride
Authors: Reis Berthold , Gerlach Niklas , Steinbach Christine , Haro Carrasco Karina , Oelmann Marina , Schwarz Simona , Müller Martin , Schwarz Dana
Published: July 2021

The modification of the biobased polymer chitosan is a broad and widely studied field. Herein, an insight into the hydrophobization of low-molecular-weight chitosan by substitution of amino functionalities with hexanoyl chloride is reported. Thereby, the influence of the pH of the reaction media was investigated. Further, methods for the determination of the degree of substitution based on 1H-NMR, FTIR, and potentiometric titration were compared and discussed regarding their accuracy and precision. 1H-NMR was the most accurate method, while FTIR and the potentiometric titration, though precise and reproducible, underlie the influence of complete protonation and solubility issues. Additionally, the impact of the pH variation during the synthesis on the properties of the samples was investigated by Cd2+ sorption experiments. The adjusted pH values during the synthesis and, therefore, the obtained degrees of substitution possessed a strong impact on the adsorption properties of the final material.
Tensile Creep Properties of Cr-Si Alloys at 980 °C in Air—Influence of Ge and Mo Addition
Authors: Pfizenmaier Petra , Ulrich Anke Silvia , Galetz Mathias C. , Glatzel Uwe
Published: July 2021

The tensile creep behavior of Cr-Si alloys with Cr ≥ 91 at.% was investigated in air at 980 °C with a constant load of 50–100 MPa. Additionally, the influence of substitutional alloying additions of 2 at.% Ge and Mo, leading to ternary alloys was studied. The addition of Ge or Mo results in an improvement in creep strength, with the highest strength achieved with addition of Mo. For longer creep exposure times a strong effect is observed, because of severe nitrogen uptake from the air, depending on alloy composition. Based on the results a novel mechanism for the impact of chromium nitride formation on the creep behavior is proposed.
Computational Fluid Dynamics (CFD) Simulation of Inclusion Motion under Interfacial Tension in a Flash Welding Process
Authors: Siddiqui Md Irfanul Haque , Alshehri Hassan , Orfi Jamel , Ali Masood Ashraf , Dobrotă Dan
Published: July 2021

Non-metallic inclusions particles are detrimental to the mechanical properties of a material. It is very important to understand the motion behavior of inclusion particles in molten metal. The motion behavior of non-metallic inclusion particles during weld pool solidification and their distribution in joint areas is dependent on various factors. In the alternative current (AC) flash welding process, inclusions motions are dependent on welding plate movement, interfacial tensions, etc. Apart from this, the temperature of the molten metal in the welding zone and the size of inclusion particles also play an important role. Secondly, the Marangoni forces are developed due to interfacial tension which affects the movement of inclusion particles at the solid-liquid interface in a solidifying welding pool. The interfacial tension varies with the change in surfactant concentration and other factors. In this work, the effect of upsetting rate and interfacial tension on alumina inclusions has been studied. The interfacial tension controls the pushing and engulfment of non-metallic inclusions at the solid-liquid interface. A two-dimensional multiphase mathematical model has been developed to study the inclusion motion behavior at the solid–liquid interface in a solidifying weld pool. The numerical model has been developed by adding the volume of fluid method (VOF), a dynamic mesh model and discrete phase model for a realistic approach. The predicted results show that the upsetting setting parameters have a substantial effect on the overall non-metallic inclusion motion. The inclusions were seen moving away from the welded joint due to the high up-setting rate. The results also reveal that the inclusions were engulfed by the solidification front under the effect of the strong interfacial tension between the non-metallic inclusions and the molten steel.
Metabolic Profiling of Plasma in Patients with Irritable Bowel Syndrome after a 4-Week Starch- and Sucrose-Reduced Diet
Authors: Stenlund Hans , Nilholm Clara , Chorell Elin , Roth Bodil , D’Amato Mauro , Ohlsson Bodil
Published: July 2021

A 4-week dietary intervention with a starch- and sucrose-restricted diet (SSRD) was conducted in patients with irritable bowel syndrome (IBS) to examine the metabolic profile in relation to nutrient intake and gastrointestinal symptoms. IBS patients were randomized to SSRD intervention (n = 69) or control continuing with their ordinary food habits (n = 22). Food intake was registered and the questionnaires IBS-symptoms severity scale (IBS-SSS) and visual analog scale for IBS (VAS-IBS) were completed. Metabolomics untargeted analysis was performed by gas chromatography mass spectrometry (GC-MS) and liquid chromatography mass spectrometry (LC-MS) in positive and negative ionization modes. SSRD led to marked changes in circulating metabolite concentrations at the group level, most prominent for reduced starch intake and increased polyunsaturated fat, with small changes in the control group. On an individual level, the correlations were weak. The marked reduction in gastrointestinal symptoms did not correlate with the metabolic changes. SSRD was observed by clear metabolic effects mainly related to linoleic acid metabolism, fatty acid biosynthesis, and beta-oxidation.
Process Intensification of 2,2′-(4-Nitrophenyl) Dipyrromethane Synthesis with a SO3H-Functionalized Ionic Liquid Catalyst in Pickering-Emulsion-Based Packed-Bed Microreactors
Authors: Zhang Hong , Shang Minjing , Zhao Yuchao , Su Yuanhai
Published: July 2021

A stable water-in-oil Pickering emulsion was fabricated with SO3H-functionalized ionic liquid and surface-modified silica nanoparticles and used for 2,2′-(4-nitrophenyl) dipyrromethane synthesis in a packed-bed microreactor, exhibiting high reaction activity and product selectivity. The compartmentalized water droplets of the Pickering emulsion had an excellent ability to confine the ionic liquid against loss under continuous-flow conditions, and the excellent durability of the catalytic system without a significant decrease in the reaction efficiency and selectivity was achieved. Compared with the reaction performance of a liquid–liquid slug-flow microreactor and batch reactor, the Pickering-emulsion-based catalytic system showed a higher specific interfacial area between the catalytic and reactant phases, benefiting the synthesis of 2,2′-(4-nitrophenyl) dipyrromethane and resulting in a higher yield (90%). This work indicated that an increase in the contact of reactants with catalytic aqueous solution in a Pickering-emulsion-based packed-bed microreactor can greatly enhance the synthetic process of dipyrromethane, giving an excellent yield of products and a short reaction time. It was revealed that Pickering-emulsion-based packed-bed microreactors with the use of ionic liquids as catalysts for interfacial catalysis have great application potential in the process of intensification of organic synthesis.
New Strains of Wolbachia Unveiling the Complexity of This Symbiotic Interaction in Solenopsis (Hymenoptera: Formicidae)
Authors: Martins Cintia , Ramalho Manuela de Oliveira , Silva Larissa Marin Rodrigues , Souza Rodrigo Fernando de , Bueno Odair Correa
Published: July 2021

Bacteria of the genus Wolbachia are widely distributed in arthropods, particularly in ants; nevertheless, it is still little explored with the Multilocus Sequence Typing (MLST) methodology, especially in the genus Solenopsis, which includes species native to South America. Ants from this genus have species distributed in a cosmopolitan way with some of them being native to South America. In Brazil, they are widely spread and preferentially associated with areas of human activity. This study aimed to investigate the diversity of Wolbachia in ants of the genus Solenopsis through the MLST approach and their phylogenetic relationship, including the relationship between mtDNA from the host and the related Wolbachia strain. We also tested the geographic correlation between the strains to infer transmission and distributional patterns. Fifteen new strains and eleven previously unknown alleles were obtained by sequencing and analyzing the five genes that make up the MLST. The phylogenetic relationship between the strains showed a polyphyletic pattern, indicative of the complexity of the evolutionary history of these bacteria in the analyzed species. We detected the correlation of host’s mitochondrial DNA with Wolbachia diversity which imply that related strains exist in related hosts, strongly suggesting the occurrence of vertical transfer. We found no specificity of the Wolbachia strain for a given geographic region that could indicate either that there is no horizontal transfer of the strain from the environment for the host or that the human action could be shuffling the distribution of the Solenopsis ants and the endosymbiont Wolbachia, as well. Our study highlights the complexity and novelty of Wolbachia diversity with this specific group of ants and the need for further studies that focus on understanding of this intricate relationship.