bluuebunny/crossref_metadata_2025 huggingface dataset:
Are Physical Experiences with the Balance Model Beneficial for Students’ Algebraic Reasoning? An Evaluation of two Learning Environments for Linear Equations
Authors: Otten Mara , van den Heuvel-Panhuizen Marja , Veldhuis Michiel , Boom Jan , Heinze Aiso
Published: June 2020

The balance model is often used for teaching linear equation solving. Little research has investigated the influence of various representations of this model on students’ learning outcomes. In this quasi-experimental study, we examined the effects of two learning environments with balance models on primary school students’ reasoning related to solving linear equations. The sample comprised 212 fifth-graders. Students’ algebraic reasoning was measured four times over the school year; students received lessons in between two of these measurements. Students in Intervention Condition 1 were taught linear equation solving in a learning environment with only pictorial representations of the balance model, while students in Intervention Condition 2 were taught in a learning environment with both physical and pictorial representations of the balance model, which allowed students to manipulate the model. Multi-group latent variable growth curve modelling revealed a significant improvement in algebraic reasoning after students’ participation in either of the two intervention conditions, but no significant differences were found between intervention conditions. The findings suggest that the representation of the balance model did not differentially affect students’ reasoning. However, analyzing students’ reasoning qualitatively revealed that students who worked with the physical balance model more often used representations of the model or advanced algebraic strategies, suggesting that different representations of the balance model might play a different role in individual learning processes.
Learning to See in Extremely Low-Light Environments with Small Data
Authors: Xu Yifeng , Wang Huigang , Cooper Garth Douglas , Rong Shaowei , Sun Weitao
Published: June 2020

Recent advances in deep learning have shown exciting promise in various artificial intelligence vision tasks, such as image classification, image noise reduction, object detection, semantic segmentation, and more. The restoration of the image captured in an extremely dark environment is one of the subtasks in computer vision. Some of the latest progress in this field depends on sophisticated algorithms and massive image pairs taken in low-light and normal-light conditions. However, it is difficult to capture pictures of the same size and the same location under two different light level environments. We propose a method named NL2LL to collect the underexposure images and the corresponding normal exposure images by adjusting camera settings in the “normal” level of light during the daytime. The normal light of the daytime provides better conditions for taking high-quality image pairs quickly and accurately. Additionally, we describe the regularized denoising autoencoder is effective for restoring a low-light image. Due to high-quality training data, the proposed restoration algorithm achieves superior results for images taken in an extremely low-light environment (about 100× underexposure). Our algorithm surpasses most contrasted methods solely relying on a small amount of training data, 20 image pairs. The experiment also shows the model adapts to different brightness environments.
Using SCADA Data for Wind Turbine Condition Monitoring: A Systematic Literature Review
Authors: Maldonado-Correa Jorge , Martín-Martínez Sergio , Artigao Estefanía , Gómez-Lázaro Emilio
Published: June 2020

Operation and maintenance (O&M) activities represent a significant share of the total expenditure of a wind farm. Of these expenses, costs associated with unexpected failures account for the highest percentage. Therefore, it is clear that early detection of wind turbine (WT) failures, which can be achieved through appropriate condition monitoring (CM), is critical to reduce O&M costs. The use of Supervisory Control and Data Acquisition (SCADA) data has recently been recognized as an effective solution for CM since most modern WTs record large amounts of parameters using their SCADA systems. Artificial intelligence (AI) techniques can convert SCADA data into information that can be used for early detection of WT failures. This work presents a systematic literature review (SLR) with the aim to assess the use of SCADA data and AI for CM of WTs. To this end, we formulated four research questions as follows: (i) What are the current challenges of WT CM? (ii) What are the WT components to which CM has been applied? (iii) What are the SCADA variables used? and (iv) What AI techniques are currently under research? Further to answering the research questions, we identify the lack of accessible WT SCADA data towards research and the need for its standardization. Our SLR was developed by reviewing more than 95 scientific articles published in the last three years.
Experimental Investigation on a Vapor Injection Heat Pump System with a Single-Stage Compressor
Authors: Liu Hongzhi , Nagano Katsunori , Katsura Takao , Han Yue
Published: June 2020

In this study, a heat pump of 10 kW with vapor injection using refrigerant of R410A was developed. A vapor injection pipe connecting a gas–liquid separator at the outlet of the main expansion valve and the suction of a single-stage rotary compressor was designed. The heating performance of this vapor injection heat pump was investigated and analyzed at different compressor frequencies and primary temperatures. The experimental results show that for the heat pump without vapor injection, the heating capacity increased linearly with the compressor frequency, while the heating coefficient of performance (COP) decreased linearly with the compressor frequency for each tested primary temperature. The developed vapor injection technique is able to increase the heat pump system’s heating capacity and heating COP when the injection ratio R falls into the range 0.16–0.17. The refrigerant mass flow rate can be increased in the vapor injection heat pump cycle due to the decreased specific volume of the suction refrigerant. The power consumption of vapor injection heat pump cycle almost remains the same with that of the conventional heat pump cycle because of the increased refrigerant mass flow rate and the decreased compression ratio. Finally, it was found that the developed vapor injection cycle is preferable to decreasing the compressor’s discharge temperature.
Analysis of the Potential for Gas Micro-Cogeneration Development in Poland Using the Monte Carlo Method
Authors: Kryzia Dominik , Kuta Marta , Matuszewska Dominika , Olczak Piotr
Published: June 2020

Micro-cogeneration (mCHP) is a promising solution for the generation of heat and electricity in households, it contributes to reducing carbon dioxide emissions in countries where the production of electricity is mainly based on fossil fuels. Its dissemination in Poland faces barriers in the form of high purchase prices in relation to electricity productivity. In this work 1% of the household population in Poland was analyzed using the Monte Carlo method. It was found that for mCHP to become economically profitable for a group of at least 10,000 households, its price should fall from around 18,000 euros (711.5 euros/kWth and 18,000 euros/kWe) to 4800 euros (189.7 euros/kWth and 4800 euros/kWe) and for 100,000 households to 4100 euros (162.1 euros/kWth and 4100 euros/kWe). These calculations were made for fixed gas and electricity prices. The analysis also included cases of various changes in gas and energy prices. Faster growth of electricity prices than gas prices reduce the profitability barrier. In addition, a building located in Lesser Poland region was analyzed, with an above average demand for electricity and heat. Gas micro-cogeneration becomes profitable for this household at a price of 3700 euros (146.2 euros/kWth and 3700 euros/kWe) at fixed gas and electricity prices.
A Gini Coefficient-Based Impartial and Open Dispatching Model
Authors: Sun Liang , Zhang Na , Li Ning , Song Zhuo-ran , Li Wei-dong
Published: June 2020

According to the existing widely applied impartial and open dispatching models, operation fairness was mainly emphasized, which severely restricted the optimization space of the economy of the overall system operation and affected the economic benefits. To solve the above problems, a scheduling model based on Gini coefficient under impartial and open dispatching principle is proposed in this paper, which can consider the balance between the fairness and economy of system operation. In the proposed model, the Gini coefficient is introduced to describe the fairness of electric energy completion rate among different generation units in the form of constraint conditions. Because the electricity production schedule can reflect the economic income of the electric power enterprise, and the Gini coefficient is used as an economic statistical indicator to evaluate the fairness in the overall distribution of income in social statistics, it is more appropriate to be used to measure the fairness of the power generation dispatching. The objective of the proposed model is to minimize the total operation costs. In the model, the balance between the system operation economy and fairness can be realized by adjusting the Gini coefficient value. The simulation results show that the proposed model is an extension of the traditional model. Compared with the traditional economic dispatching model and normal “impartial and open dispatching” model, the proposed model can better coordinate the relationship between fairness and economy. It could provide more choices for power generation dispatchers. It could also provide a reference for regulatory departments to formulate relevant policies by adjusting the threshold value of the Gini coefficient. Case studies show that the power dispatching decisions according to the proposed model can provide a scientific and fair reference basis for dispatching schemes, and could reduce the generation costs and also achieve optimal allocation of resources on the basis of ensuring fair dispatching.
Pressure Loss Reduction in an Innovative Directional Poppet Control Valve
Authors: Filo Grzegorz , Lisowski Edward , Rajda Janusz
Published: June 2020

This article presents the results of computational fluid dynamics (CFD) analysis of an innovative directional control valve consisting of four poppet seat valves and two electromagnets enclosed inside a single body. The valve has a unique design, allowing the use of any poppet valve configuration. Both normally opened (NO) and normally closed (NC) seat valves can be applied. The combination of four universal valve seats and two electromagnets gives a wide range of flow path configurations. This significantly increases the possibility of practical applications. However, due to the significant miniaturization of the valve body and the requirement to obtain necessary connections between flow paths, multiple geometrically complex channels had to be made inside the body. Hence, the main purpose of work was to shape the geometry of the flow channels in such a way as to minimize pressure losses. During the CFD analyses velocity distribution in flow channels and pressure distribution on the walls were determined. The results were used to obtain pressure loss as a function of flow rate, which was then verified by means of laboratory experiments conducted on a test bench.
Multi-Criteria Examination of Power-to-Gas Pathways under Stochastic Preferences
Authors: Walker Sean , Al-Zakwani Suadd , Maroufmashat Azadeh , Fowler Michael , Elkamel Ali
Published: June 2020

Power-to-gas is an energy storage and vector technology which can utilize off-peak power, assist in the integration of renewable power and provide needed fuel for industry and transportation. Further, power-to-gas is a useful technology for balancing surplus baseload and renewable energy generation with demand. There are numerous applications of power-to-gas in Europe, where renewable power is used to generate hydrogen for numerous applications. Examining each of these power-to-gas pathways across quantitative and qualitative criteria, this paper utilizes the stochastic fuzzy analytic hierarchy process to determine criteria weights. These weights are then fed to a multiple criteria decision analysis tool to determine the viability of each pathway for investors and policy makers. A sensitivity analysis is carried out by reprioritizing the criteria and re-evaluating the multiple criteria analysis. The two pathways that score highest under multiple criteria rankings are power-to-gas to mobility-fuel and power-to-gas-to-power, due to their established technologies, lower costs and environmental performance. By extension, both of these power-to-gas pathways are the most appropriate ways for this technology to be implemented, due to their combination of public familiarity, emissions reductions, and developed, available technologies.
Reactive Power Control Method for Enhancing the Transient Stability Total Transfer Capability of Transmission Lines for a System with Large-Scale Renewable Energy Sources
Authors: Zhang Yuwei , Liu Wenying , Wang Fangyu , Zhang Yaoxiang , Li Yalou
Published: June 2020

With the increased proportion of intermittent renewable energy sources (RES) integrated into the sending-end, the total transfer capability of transmission lines is not sufficient during the peak periods of renewable primary energy (e.g., the wind force), causing severe RES power curtailment. The total transfer capability of transmission lines is generally restricted by the transient stability total transfer capability (TSTTC). This paper presents a reactive power control method to enhance the TSTTC of transmission lines. The key is to obtain the sensitivity between TSTTC and reactive power, while the Thevenin equivalent voltage is the link connecting TSTTC and reactive power. The Thevenin theorem states that an active circuit between two load terminals can be considered as an individual voltage source. The voltage of this source would be open-circuit voltage across the terminals, and the internal impedance of the source is the equivalent impedance of the circuit across the terminals. The Thevenin voltage used in Thevenin’s theorem is an ideal voltage source equal to the open-circuit voltage at the terminals. Thus, the sensitivities between TSTTC and the Thevenin equivalent voltages of the sending-end and receiving-end were firstly derived using the equal area criterion. Secondly, the sensitivity between the Thevenin equivalent voltage and reactive power was derived using the total differentiation method. By connecting the above sensitivities together with the relevant parameters calculated from Thevenin equivalent parameter identification and power flow equation, the sensitivity between TSTTC and reactive power was obtained, which was used as the control priority in the proposed reactive power control method. At last, the method was applied to the Gansu Province Power Grid in China to demonstrate its effectiveness, and the accuracy of the sensitivity between TSTTC and reactive power was verified.
Fractal Dimension Analysis Applied to Soil CO2 Fluxes in Campotosto’s Seismic Area, Central Italy
Authors: D’Incecco Simone , Di Carlo Piero , Aruffo Eleonora , Chatzisavvas Nikolaos , Petraki Ermioni , Priniotakis Georgios , Voyiatzis Ioannis , Yannakopoulos Panayiotis H. , Nikolopoulos Dimitrios
Published: June 2020

This article reports fractal dimension analysis applied to soil CO2 fluxes measured in an Italian seismic area. The work was carried out with the use of a calibrated flux chamber unit. The fractal dimension (FD) from isotropic variograms was used as a method to understand related scale-dependent phenomena. The aim was to investigate the spatial variability of CO2 flux measurements in four directions (horizontal, vertical, 45° and 135° directions) related to different distances between the measuring points and from a fault. High fractal dimension values were found (2.5 ≤ FD ≤ 3.0). These imply strong anti-persistent behavior near to and far from the fault. Lower fractal dimensions were addressed at longer distances from the fault.
Punjabis and Coeliac Disease: A Wake-Up Call
Authors: Farrukh Affifa , Mayberry John F.
Published: June 2020

Punjabis are one of the largest ethnic groups in the world, with at least 124 million members. Their diet is based around wheat cereals and they are now recognised to be at risk of coeliac disease. Indeed, the incidence of coeliac disease amongst Punjabi migrants is three times that of other Europeans, suggesting that in excess of 3 million Punjabi people may be affected by the condition. This review considers the history of coeliac disease and its lack of ready diagnosis in the Punjabi community, including the adverse outcomes as a result. It considers the poor-quality information available to Punjabi patients and tentatively suggests methods of dealing with these issues.
The COVID-19 Pandemic and the Pathology of the Economic and Political Architecture in Cameroon
Authors: Ojong Nathanael
Published: June 2020

This article examines the factors restricting an effective response to the COVID-19 pandemic in Cameroon. It argues that structural adjustment policies in the 1980s and 1990s as well as corruption and limited investment in recent times have severely weakened the country’s health system. This article also emphasises the interconnection between poverty, slums, and COVID-19. This interconnection brings to the fore inequality in Cameroon. Arguably, this inequality could facilitate the spread of COVID-19 in the country. This article draws attention to the political forces shaping the response to the pandemic and contends that in some regions in the country, the lack of an effective response to the pandemic may not necessarily be due to a lack of resources. In so doing, it critiques the COVID-19 orthodoxy that focuses exclusively on the pathology of the disease and advocates “technical” solutions to the pandemic, while ignoring the political and socio-economic forces that shape the fight against the pandemic. At times, medical supplies and other forms of assistance may be available, but structural violence impairs access to these resources. Politics must be brought into the COVID-19 discourse, as it shapes the response to the pandemic.
Evaluation of Prognostic Factors of Severity in Acute Biliary Pancreatitis
Authors: Silva-Vaz Pedro , Abrantes Ana Margarida , Morgado-Nunes Sara , Castelo-Branco Miguel , Gouveia António , Botelho Maria Filomena , Tralhão José Guilherme
Published: June 2020

Acute pancreatitis (AP) is an inflammatory disorder of the pancreas that, when classified as severe, is associated with high morbidity and mortality. Promptly identifying the severity of AP is of extreme importance for improving clinical outcomes. The aim of this study was to compare the prognostic value of serological biomarkers, ratios, and multifactorial scores in patients with acute biliary pancreatitis and to identify the best predictors. In this observational and prospective study, the biomarkers, ratios and multifactorial scores were evaluated on admission and at 48 h of the symptom onset. On admission, regarding the AP severity, the white blood count (WBC) and neutrophil–lymphocyte ratio (NLR), and regarding the mortality, the WBC and the modified Marshall score (MMS) showed the best predictive values. At 48 h, regarding the AP severity, the hepcidin, NLR, systemic inflammatory response index (SIRI) and MMS and regarding the mortality, the NLR, hepcidin and the bedside index for severity in AP (BISAP) score, showed the best predictive values. The present study enabled the identification, for the first time, of SIRI as a new prognostic tool for AP severity, and validated hepcidin and the NLR as better prognostic markers than C-reactive protein (CRP) at 48 h of symptom onset.
Identification and Characterization of Circular Intronic RNAs Derived from Insulin Gene
Authors: Das Debojyoti , Das Aniruddha , Sahu Mousumi , Mishra Smruti Sambhav , Khan Shaheerah , Bejugam Pruthvi R. , Rout Pranita K. , Das Arundhati , Bano Shehnaz , Mishra Gyan Prakash , Raghav Sunil K. , Dixit Anshuman , Panda Amaresh C.
Published: June 2020

Circular RNAs (circRNAs) are a large family of noncoding RNAs that have emerged as novel regulators of gene expression. However, little is known about the function of circRNAs in pancreatic β-cells. Here, transcriptomic analysis of mice pancreatic islet RNA-sequencing data identified 77 differentially expressed circRNAs between mice fed with a normal diet and a high-fat diet. Surprisingly, multiple circRNAs were derived from the intron 2 of the preproinsulin 2 (Ins2) gene and are termed as circular intronic (ci)-Ins2. The expression of ci-Ins2 transcripts in mouse pancreatic islets, and βTC6 cells were confirmed by reverse transcription PCR, DNA sequencing, and RNase R treatment experiments. The level of ci-Ins2 was altered in βTC6 cells upon exposure to elevated levels of palmitate and glucose. Computational analysis predicted the interaction of several RNA-binding proteins with ci-Ins2 and their flanking region, suggesting their role in the ci-Ins2 function or biogenesis. Additionally, bioinformatics analysis predicted the association of several microRNAs with ci-Ins2. Gene ontology and pathway analysis of genes targeted by miRNAs associated with ci-Ins2 suggested the regulation of several key biological processes. Together, our findings indicate that differential expression of circRNAs, especially ci-Ins2 transcripts, may regulate β-cell function and may play a critical role in the development of diabetes.
Current Perspectives on 89Zr-PET Imaging
Authors: Yoon Joon-Kee , Park Bok-Nam , Ryu Eun-Kyoung , An Young-Sil , Lee Su-Jin
Published: June 2020

89Zr is an emerging radionuclide that plays an essential role in immuno-positron emission tomography (PET) imaging. The long half-life of 89Zr (t1/2 = 3.3 days) is favorable for evaluating the in vivo distribution of monoclonal antibodies. Thus, the use of 89Zr is promising for monitoring antibody-based cancer therapies. Immuno-PET combines the sensitivity of PET with the specificity of antibodies. A number of studies have been conducted to investigate the feasibility of 89Zr immuno-PET imaging for predicting the efficacy of radioimmunotherapy and antibody therapies, imaging target expression, detecting target-expressing tumors, and the monitoring of anti-cancer chemotherapies. In this review, we summarize the current status of PET imaging using 89Zr in both preclinical and clinical studies by highlighting the use of immuno-PET for the targets of high clinical relevance. We also present 89Zr-PET applications other than immuno-PET, such as nanoparticle imaging and cell tracking. Finally, we discuss the limitations and the ongoing research being performed to overcome the remaining hurdles.
The Connexin 43 Regulator Rotigaptide Reduces Cytokine-Induced Cell Death in Human Islets
Authors: Ghiasi Seyed Mojtaba , Hansen Jakob Bondo , Christensen Dan Ploug , Tyrberg Björn , Mandrup-Poulsen Thomas
Published: June 2020

Background: Intercellular communication mediated by cationic fluxes through the Connexin family of gap junctions regulates glucose-stimulated insulin secretion and beta cell defense against inflammatory stress. Rotigaptide (RG, ZP123) is a peptide analog that increases intercellular conductance in cardiac muscle cells by the prevention of dephosphorylation and thereby uncoupling of Connexin-43 (Cx43), possibly via action on unidentified protein phosphatases. For this reason, it is being studied in human arrhythmias. It is unknown if RG protects islet cell function and viability against inflammatory or metabolic stress, a question of considerable translational interest for the treatment of diabetes. Methods: Apoptosis was measured in human islets shown to express Cx43, treated with RG or the control peptide ZP119 and exposed to glucolipotoxicity or IL-1β + IFNɣ. INS-1 cells shown to lack Cx43 were used to examine if RG protected human islet cells via Cx43 coupling. To study the mechanisms of action of Cx43-independent effects of RG, NO, IkBα degradation, mitochondrial activity, ROS, and insulin mRNA levels were determined. Results: RG reduced cytokine-induced apoptosis ~40% in human islets. In Cx43-deficient INS-1 cells, this protective effect was markedly blunted as expected, but unexpectedly, RG still modestly reduced apoptosis, and improved mitochondrial function, insulin-2 gene levels, and accumulated insulin release. RG reduced NO production in Cx43-deficient INS-1 cells associated with reduced iNOS expression, suggesting that RG blunts cytokine-induced NF-κB signaling in insulin-producing cells in a Cx43-independent manner. Conclusion: RG reduces cytokine-induced cell death in human islets. The protective action in Cx43-deficient INS-1 cells suggests a novel inhibitory mechanism of action of RG on NF-κB signaling.
The Role of Estrogen Receptors in Cardiovascular Disease
Authors: Aryan Laila , Younessi David , Zargari Michael , Banerjee Somanshu , Agopian Jacqueline , Rahman Shadie , Borna Reza , Ruffenach Gregoire , Umar Soban , Eghbali Mansoureh
Published: June 2020

Cardiovascular Diseases (CVDs) are the leading cause of death globally. More than 17 million people die worldwide from CVD per year. There is considerable evidence suggesting that estrogen modulates cardiovascular physiology and function in both health and disease, and that it could potentially serve as a cardioprotective agent. The effects of estrogen on cardiovascular function are mediated by nuclear and membrane estrogen receptors (ERs), including estrogen receptor alpha (ERα), estrogen receptor beta (ERβ), and G-protein-coupled ER (GPR30 or GPER). Receptor binding in turn confers pleiotropic effects through both genomic and non-genomic signaling to maintain cardiovascular homeostasis. Each ER has been implicated in multiple pre-clinical cardiovascular disease models. This review will discuss current reports on the underlying molecular mechanisms of the ERs in regulating vascular pathology, with a special emphasis on hypertension, pulmonary hypertension, and atherosclerosis, as well as in regulating cardiac pathology, with a particular emphasis on ischemia/reperfusion injury, heart failure with reduced ejection fraction, and heart failure with preserved ejection fraction.
Expression Changes and Impact of the Extracellular Matrix on Etoposide Resistant Human Retinoblastoma Cell Lines
Authors: Reinhard Jacqueline , Wagner Natalie , Krämer Miriam M. , Jarocki Marvin , Joachim Stephanie C. , Dick H. Burkhard , Faissner Andreas , Kakkassery Vinodh
Published: June 2020

Retinoblastoma (RB) represents the most common malignant childhood eye tumor worldwide. Several studies indicate that the extracellular matrix (ECM) plays a crucial role in tumor growth and metastasis. Moreover, recent studies indicate that the ECM composition might influence the development of resistance to chemotherapy drugs. The objective of this study was to evaluate possible expression differences in the ECM compartment of the parental human cell lines WERI-RB1 (retinoblastoma 1) and Y79 and their Etoposide resistant subclones via polymerase chain reaction (PCR). Western blot analyses were performed to analyze protein levels. To explore the influence of ECM molecules on RB cell proliferation, death, and cluster formation, WERI-RB1 and resistant WERI-ETOR cells were cultivated on Fibronectin, Laminin, Tenascin-C, and Collagen IV and analyzed via time-lapse video microscopy as well as immunocytochemistry. We revealed a significantly reduced mRNA expression of the proteoglycans Brevican, Neurocan, and Versican in resistant WERI-ETOR compared to sensitive WERI-RB1 cells. Also, for the glycoproteins α1-Laminin, Fibronectin, Tenascin-C, and Tenascin-R as well as Collagen IV, reduced expression levels were observed in WERI-ETOR. Furthermore, a downregulation was detected for the matrix metalloproteinases MMP2, MMP7, MMP9, the tissue-inhibitor of metalloproteinase TIMP2, the Integrin receptor subunits ITGA4, ITGA5 and ITGB1, and all receptor protein tyrosine phosphatase β/ζ isoforms. Downregulation of Brevican, Collagen IV, Tenascin-R, MMP2, TIMP2, and ITGA5 was also verified in Etoposide resistant Y79 cells compared to sensitive ones. Protein levels of Tenascin-C and MMP-2 were comparable in both WERI cell lines. Interestingly, Fibronectin displayed an apoptosis-inducing effect on WERI-RB1 cells, whereas an anti-apoptotic influence was observed for Tenascin-C. Conversely, proliferation of WERI-ETOR cells was enhanced on Tenascin-C, while an anti-proliferative effect was observed on Fibronectin. In WERI-ETOR, cluster formation was decreased on the substrates Collagen IV, Fibronectin, and Tenascin-C. Collectively, we noted a different ECM mRNA expression and behavior of Etoposide resistant compared to sensitive RB cells. These findings may indicate a key role of ECM components in chemotherapy resistance formation of RB.
A Novel Structural Health Monitoring Method for Reinforced Concrete Bridge Decks Using Ultrasonic Guided Waves
Authors: Erdogmus Ece , Garcia Eric , Amiri Ahmad Shoaib , Schuller Michael
Published: June 2020

This article presents the latest improvements in a recently developed nondestructive testing (NDT) approach for early detection of various flaws (corrosion, delamination, and concrete cracking) in reinforced concrete (RC) bridge decks. The proposed method involves the use of internal steel reinforcement as a wave guide for transmitting ultrasonic waves through the system and the measurement of leaked energy from the surface of the concrete. This paper builds upon the progress made in the previously published phases of the project and aims to further explore the capabilities and practicality of the proposed NDT method. Specifically, the limits of propagation distance, effect of bidirectional reinforcement, methods of attachment and coupling of the sensors to the reinforcement and concrete, and suggestions for optimal sensor arrays are discussed in this paper based on the findings from the most recent laboratory tests and pilot field tests. The results show that with careful placement of sensors and data interpretation, early stages of localized corrosion and delamination can be detected, even when bidirectional and multiple layers of reinforcement are present. For field applications, an angled seat made of fast-setting Hydrocal gypsum cement is recommended, and it is projected that the optimal angle of attachment is 33 degrees or less from the vertical axis.
Toward the Integration of an Attract-and-Kill Approach with Entomopathogenic Nematodes to Control Multiple Life Stages of Plum Curculio (Coleoptera: Curculionidae)
Authors: Piñero Jaime C. , Shapiro-Ilan David , Cooley Daniel R. , Tuttle Arthur F. , Eaton Alan , Drohan Patrick , Leahy Kathleen , Zhang Aijun , Hancock Torri , Wallingford Anna K. , Leskey Tracy C.
Published: June 2020

Efforts to reduce insecticide inputs against plum curculio, Conotrachelus nenuphar, a key pest of apples in eastern North America, include perimeter-row insecticide sprays applied after the whole-orchard petal fall spray to manage dispersing adults and, more recently, insecticide sprays confined to odor-baited trap trees. Entomopathogenic nematodes (EPNs) are virulent to ground-dwelling stages of C. nenuphar, and may be applied to the ground underneath trap-tree canopies. Here, we (1) compared the efficacy of the odor-baited trap tree approach with grower-prescribed (=grower standard) sprays to manage C. nenuphar populations over a six-year period in seven commercial apple orchards in New England; and (2) assessed the performance of the EPN Steinernema riobrave at suppressing ground-dwelling stages of C. nenuphar. In addition, the performance of S. riobrave was compared against that of S. carpocapsae and S. feltiae in one year. Across the six years, percent fruit injury on trap tree plots averaged 11.3% on odor-baited trap trees and 1.4% on unbaited trees in grower standard plots, highlighting the ability of trap trees to aggregate C. nenuphar activity and subsequent injury. Mean percentage injury on fruit sampled from interior trees, the strongest measure of treatment performance, in trap tree plots did not differ significantly from that recorded on interior trees in grower standard spray plots (0.95 vs. 0.68%, respectively). Steinernema riobrave consistently reduced C. nenuphar populations as indicated by the significantly lower number of adult C. nenuphar that emerged from the soil, when compared to water control. Steinernema carpocapsae and S. riobrave performed similarly well, and both EPN species outperformed S. feltiae. Our combined findings indicate that an IPM approach that targets multiple life stages of C. nenuphar has the potential to manage this pest more sustainably in a reduced-spray environment.
Modeling Portfolio Credit Risk Taking into Account the Default Correlations Using a Copula Approach: Implementation to an Italian Loan Portfolio
Authors: Di Clemente Annalisa
Published: June 2020

This work aims to illustrate an advanced quantitative methodology for measuring the credit risk of a loan portfolio allowing for diversification effects. Also, this methodology can allocate the credit capital coherently to each counterparty in the portfolio. The analytical approach used for estimating the portfolio credit risk is a binomial type based on a Monte Carlo Simulation. This method takes into account the default correlations among the credit counterparties in the portfolio by following a copula approach and utilizing the asset return correlations of the obligors, as estimated by rigorous statistical methods. Moreover, this model considers the recovery rates as stochastic and dependent on each other and on the time until defaults. The methodology utilized for coherently allocating credit capital in the portfolio estimates the marginal contributions of each obligor to the overall risk of the loan portfolio in terms of Expected Shortfall (ES), a risk measure more coherent and conservative than the traditional measure of Value-at-Risk (VaR). Finally, this advanced analytical structure is implemented to a hypothetical, but typical, loan portfolio of an Italian commercial bank operating across the overall national country. The national loan portfolio is composed of 17 sub-portfolios, or geographic clusters of credit exposures to 10,500 non-financial firms (or corporates) belonging to each geo-cluster or sub-portfolio. The outcomes, in terms of correlations, portfolio risk measures and capital allocations obtained from this advanced analytical framework, are compared with the results found by implementing the Internal Rating Based (IRB) approach of Basel II and III. Our chief conclusion is that the IRB model is unable to capture the real credit risk of loan portfolios because it does not take into account the actual dependence structure among the default events, and between the recovery rates and the default events. We underline that the adoption of this regulatory model can produce a dangerous underestimation of the portfolio credit risk, especially when the economic uncertainty and the volatility of the financial markets increase.
Land Engineering Consolidates Degraded Sandy Land for Agricultural Development in the Largest Sandy Land of China
Authors: Wang Yongsheng , Li Yuheng , Li Yurui
Published: June 2020

Sandification has become a major obstacle to China’s regional farmland protection, economic development, and ecological civilization construction. It is urgent to adopt advanced ideas and practical actions to reverse the sandy land. Structural consolidation theory was introduced to rehabilitate sandy land into farmland by soil body building, soil layer reconstruction, and soil quality improvement. A field experiment was conducted in Mu Us Sandy Land to explore the effects of blended guest materials (red clay and loess) with sand at four volume ratios (1:1, 1:2, 1:3 and 1:5) on crop yields, soil properties, and root growth. Red clay and loess significantly increased clay and silt contents and regulated the soil total nitrogen concentration and organic matter content during the critical growth stage of maize. Red clay and loess had a significant promotion of maize and soybean yields at a volume ratio of 1:3. The maximum potato yield was 42,501 and 37,332 kg ha−1 in red clay treatment at a volume ratio of 1:5 and in loess treatment at a volume ratio of 1:3, respectively. Lowest root biomass in surface soil and surface/subsoil root biomass ratio mediated maize growth in red clay treatment. Red clay was considered as the better material to rehabilitate sandy land and develop agriculture in the long-term according to the engineering costs and crop yields. Water sustainable utilization strategies and potential popularization areas of sandy land structural consolidation should be enhanced in the future.
Backward Reasoning and Epistemic Actions in Discovering Processes of Strategic Games Problems
Authors: Barbero Marta , Gómez-Chacón Inés M. , Arzarello Ferdinando
Published: June 2020

The paper focuses on the cognitive and epistemic characterization of backward reasoning in strategy games resolution. It explores the use of abstraction in context (AiC) theory as a tool for the analysis of the epistemic actions involved in these processes. We follow a qualitative methodology based on design experiments, focusing on a study carried out with mathematics and engineering students. The analysis allowed us to combine the two models derived from the epistemology of mathematical backward reasoning and AiC theory in a unified framework that allowed us to focus both short-term and long-term processes in mathematical activities. Recurring patterns of epistemic actions were identified.
Some New Fuzzy Fixed Point Results with Applications
Authors: Al-Mezel Saleh Abdullah , Ahmad Jamshaid , De La Sen Manuel
Published: June 2020

The aim of this article is to establish some fixed point results for fuzzy mappings and derive some corresponding multivalued mappings results of literature. For this purpose, we define some new and generalized contractions in the setting of b-metric spaces. As applications, we find solutions of integral inclusions by our obtained results.
Tumor Suppressors—HTRA Proteases and Interleukin-12—in Pediatric Asthma and Allergic Rhinitis Patients
Authors: Renke Joanna , Wasilewska Eliza , Kędzierska-Mieszkowska Sabina , Zorena Katarzyna , Barańska Sylwia , Wenta Tomasz , Liberek Anna , Siluk Danuta , Żurawa-Janicka Dorota , Szczepankiewicz Aleksandra , Renke Marcin , Lipińska Barbara
Published: June 2020

Background and objective: Allergy belongs to a group of mast cell-related disorders and is one of the most common diseases of childhood. It was shown that asthma and allergic rhinitis diminish the risk of various cancers, including colon cancer and acute lymphoblastic leukemia. On the other hand, asthma augments the risk of lung cancer and an increased risk of breast cancer in patients with allergy has been observed. Thus, the relation between allergy and cancer is not straightforward and furthermore, its biological mechanism is unknown. The HTRA (high temperature requirement A) proteases promote apoptosis, may function as tumor suppressors and HTRA1 is known to be released by mast cells. Interleukin-12 (Il-12) is an important cytokine that induces antitumor immune responses and is produced mainly by dendritic cells that co-localize with mast cells in superficial organs. Material and methods: In the present study we have assessed with ELISA plasma levels of the HTRA proteins, Il-12, and of the anti-HTRA autoantibodies in children with allergy (40) and in age matched controls (39). Children are a special population, since they usually do not have comorbidities and take not many drugs the processes we want to observe are not influenced by many other factors. Results: We have found a significant increase of HTRA1, 2 and 3, and of the Il-12 levels in the children with atopy (asthma and allergic rhinitis) compared to controls. Conclusion: Our results suggest that the HTRA1–3 and Il-12 levels might be useful in analyzing the pro- and antioncogenic potential in young atopic patients.
Lactation Ketoacidosis: A Systematic Review of Case Reports
Authors: Al Alawi Abdullah M. , Al Flaiti Asma , Falhammar Henrik
Published: June 2020

Background and Objective: Lactation ketoacidosis is a rare cause of high anion gap metabolic acidosis affecting breastfeeding mothers. We aim to review and analyze all cases of lactation ketoacidosis reported. Materials and Methods: A systematic search of PubMed/MEDLINE and Cumulative Index to Nursing and Allied Health Literature (CINAHL), identifying relevant case reports published from 1 January 1970 to 31 December 2019. We extracted the following data: the first author, country, year of publication, age of the mother, age of the child, weight/body mass index (BMI) of the mother, precipitating factors, presenting symptoms, biochemical results, treatment, breastfeeding, and time from presentation to the resolution of ketoacidosis. Results: Sixteen case reports and 1 case series reporting 18 cases of lactation ketoacidosis were found. Presenting symptoms were nausea (72%, 13/18), vomiting (67%, 12/18), malaise (56%, 10/18), abdominal pain (44%, 8/18), dyspnea (33%, 6/18), headache (22%, 4/18), and palpitation (11%, 2/18). Dieting and physical exercise to lose weight were reported in 76% (14/18). The treatments included IV dextrose, sodium bicarbonate, insulin, rehydration, monitoring and replacement of electrolytes, and resumption of a balanced diet. The prognoses were good, with no mortalities. Conclusions: lactation ketoacidosis should be suspected in unwell breastfeeding women with high anion gap metabolic acidosis, after excluding other causes.
Feasibility of Calcium Sulfate Moulds Made by Inkjet 3D Printing for Rapid Casting of Aluminium Alloys
Authors: Rodríguez-González Pablo , Robles Valero Pablo Eduardo , Fernández-Abia Ana Isabel , Castro-Sastre María Ángeles , Barreiro García Joaquín
Published: June 2020

In this research, a comparative analysis has been carried out between a traditional sand casting process and a modern mould obtained by additive manufacturing (AM), in the context of aluminium parts production. In this case of AM, an inkjet 3D printing (3DP) process allowed us to create a ceramic mould. A numerical simulation was carried out to study the filling and cooling rates of both parts. The design freedom typical of the 3DP technique allowed us to optimize the filling system. The results showed that in sand moulding, the speed in the gate suddenly increased when the liquid metal entered the part cavity, leading to severe turbulence due to the fountain effect. The input of air is related to the speed in the gate. Nevertheless, the results showed that when using the 3DP mould, the speed in the gate remained constant and the filling process was homogenous. With regard to the dimensional precision, while the staircase effect in the surface of the 3DP mould is the most critical aspect to control, in the sand casting mould the critical aspect is the dimensional precision of the pattern. Microstructures of the cross-section of the moulded parts showed folded shapes and air input in sand casting, which could be produced by the severe turbulence and the oxide film present in the melt during the filling process. On the other hand, the porosity found in parts produced with the 3DP mould corresponds to shrinkage; during the filling process, the remaining binder is vaporized, creating nucleation points. In this way, pores are formed by shrinkage and a mixture of shrinkage and gas entrapment. With these considerations, it can be concluded that AM shows feasibility and advantages as an alternative to the sand casting method for aluminium alloys.
Vitamin D-Induced Molecular Mechanisms to Potentiate Cancer Therapy and to Reverse Drug-Resistance in Cancer Cells
Authors: Negri Mariarosaria , Gentile Annalisa , de Angelis Cristina , Montò Tatiana , Patalano Roberta , Colao Annamaria , Pivonello Rosario , Pivonello Claudia
Published: June 2020

Increasing interest in studying the role of vitamin D in cancer has been provided by the scientific literature during the last years, although mixed results have been reported. Vitamin D deficiency has been largely associated with various types of solid and non-solid human cancers, and the almost ubiquitous expression of vitamin D receptor (VDR) has always led to suppose a crucial role of vitamin D in cancer. However, the association between vitamin D levels and the risk of solid cancers, such as colorectal, prostate and breast cancer, shows several conflicting results that raise questions about the use of vitamin D supplements in cancer patients. Moreover, studies on vitamin D supplementation do not always show improvements in tumor progression and mortality risk, particularly for prostate and breast cancer. Conversely, several molecular studies are in agreement about the role of vitamin D in inhibiting tumor cell proliferation, growth and invasiveness, cell cycle arrest and inflammatory signaling, through which vitamin D may also regulate cancer microenvironment through the activation of different molecular pathways. More recently, a role in the regulation of cancer stem cells proliferation and short non-coding microRNA (miRNAs) expression has emerged, conferring to vitamin D a more crucial role in cancer development and progression. Interestingly, it has been shown that vitamin D is able not only to potentiate the effects of traditional cancer therapy but can even contribute to overcome the molecular mechanisms of drug resistance—often triggering tumor-spreading. At this regard, vitamin D can act at various levels through the regulation of growth of cancer stem cells and the epithelial–mesenchymal transition (EMT), as well as through the modulation of miRNA gene expression. The current review reconsiders epidemiological and molecular literature concerning the role of vitamin D in cancer risk and tumor development and progression, as well as the action of vitamin D supplementation in potentiating the effects of drug therapy and overcoming the mechanisms of resistance often triggered during cancer therapies, by critically addressing strengths and weaknesses of available data from 2010 to 2020.
Efficacy and Safety of a Ketogenic Diet in Children and Adolescents with Refractory Epilepsy—A Review
Authors: Wells Jana , Swaminathan Arun , Paseka Jenna , Hanson Corrine
Published: June 2020

Epilepsy in the pediatric and adolescent populations is a devastating condition where individuals are prone to recurrent epileptic seizures or changes in behavior or movement that is the direct result of a primary change in the electrical activity in the brain. Although many children with epilepsy will have seizures controlled with antiseizure medications (ASMs), a large percentage of patients are refractory to drug therapy and may consider initiating a ketogenic diet. The term Ketogenic Diet or Ketogenic Diet Therapy (KDT) refers to any diet therapy in which dietary composition results in a ketogenic state of human metabolism. Currently, there are 4 major Ketogenic diet therapies—the classic ketogenic diet (cKD), the modified Atkins diet (MAD), the medium chain triglyceride ketogenic diet (MCTKD) and the low glycemic index treatment (LGIT). The compositions of the 4 main KDTs differ and limited evidence to distinguish the efficacy among different diets currently exists. Although it is apparent that more randomized controlled trials (RCTs) and long-term studies are needed to evaluate efficacy, side effects and individual response to the diet, it is imperative to study and understand the metabolic profiles of patients with epilepsy in order to isolate which dietary restrictions are necessary to maximize clinical benefit.