bluuebunny/crossref_metadata_2025 huggingface dataset:
A Greenhouse Test to Explore and Evaluate Light-Emitting Diode (LED) Insect Traps in the Monitoring and Control of Trialeurodes vaporariorum
Authors: Zhang Jihong , Li Huyin , Liu Maorong , Zhang Huan , Sun Hai , Wang Hongtuo , Miao Lin , Li Miaomiao , Shu Ruihao , Qin Qilian
Published: February 2020

Population control of small sucking insects has been challenging, and alternative control methods are constantly being sought. Visual traps have long been used to monitor and control pests. Colored sticky cards are widely used for diurnal pests, but their effects are influenced by environmental light conditions. Artificial light traps are mostly used for nocturnal pests. Here, we explored and evaluated light-emitting diode (LED) traps for the monitoring and control of small diurnal sucking insects using greenhouse tests targeting the greenhouse whitefly Trialeurodes vaporariorum. We tested the trapping efficacy of the LED water pan trap, assessed the most attractive LED light and analyzed its efficacy under different weather conditions. The results showed that the LED water pan trap was too inefficient to be useful. Green LEDs were more attractive than yellow LEDs, UV LEDs and green-UV combinations. Regardless of sunny or cloudy conditions, the green LED trap caught more than twice the number of whiteflies than the yellow sticky card alone under summer shading conditions. Our study suggests that LED traps have a significant field application value in whitefly mass trapping and may also be efficient for other diurnal insects. The design of LED traps specific for diurnal insects is discussed.
Effect of an Electronic Medical Record-Based Screening System on a Rapid Response System: 8-Years’ Experience of a Single Center Cohort
Authors: Lee Se Hee , Lim Chae-Man , Koh Younsuck , Hong Sang-Bum , Huh Jin Won
Published: February 2020

An electronic medical record (EMR)-based screening system has been developed as a trigger system for a rapid response team (RRT) that traditionally used direct calling. We compared event characteristics, intensive care unit (ICU) admission, and 28-day mortality following RRT activation of the two trigger systems. A total of 10,026 events were classified into four groups according to the activation time (i.e., daytime or on-call time) and the triggering type (i.e., calling or screening). Among surgical patients, the ICU admission was lowest for the on-call screening group (26.2%). Compared to the on-call screening group, the on-call calling group and daytime calling group showed higher ICU admission with an odds ratio (OR) of 2.07 (95% CI 1.50–2.84, p < 0.001) and OR of 2.68 (95% CI 1.91–3.77, p < 0.001), respectively. The 28-day mortality was lowest for the on-call screening group (8.7%). Compared to the on-call screening group, on-call calling (OR 1.88, 95% CI 1.20–2.95, p = 0.006) and daytime calling (OR 1.89, 95% CI 1.17–3.05, p < 0.001) showed higher 28-day mortality. The EMR-based screening system might be useful in detecting at-risk surgical patients, particularly during on-call time. The clinical usefulness of an EMR-based screening system can vary depending on patients’ characteristics.
Imaging and Imaging-Based Management of Pediatric Thyroid Nodules
Authors: Iakovou Ioannis , Giannoula Evanthia , Sachpekidis Christos
Published: February 2020

Thyroid nodules are less frequent in children than adults. Childhood thyroid nodules carry specific features, including a higher risk of malignancy than nodules in adults, rendering them unique in terms of management. Subsequently, they should be considered a distinct clinical entity with specific imaging recommendations. Initial evaluation requires a thorough workup, including clinical examination, and a detailed personal and familial history to determine the presence of possible risk factors. Laboratory and radiologic evaluation play an integral part in the diagnostic algorithm, with ultrasonography (US) being the first diagnostic test in all patients. US elastography has been recently introduced as an incremental method, reducing the subjectivity of the clinical diagnosis of nodule firmness associated with increased malignancy risk. However, fine-needle aspiration biopsy (FNAB) remains the mainstay in the diagnostic work-up of thyroid nodules and is documented to be best method for differentiating benign from malignant thyroid nodules. In addition, thyroid scintigraphy provides functional imaging information, which has a role both in the diagnostic management of thyroid nodules and during follow up in malignancies. Finally, despite providing additional information in certain clinical scenarios, 18F-fludeoxyglucose Positron Emission Tomography (18F-FDG-PET), computed tomography (CT), and magnetic resonance imaging (MRI) imaging are not routinely recommended for the evaluation of patients with newly detected thyroid nodules or in all cases of thyroid cancer. The objective of this review is to summarize the concepts in imaging and imaging-based management of nodular thyroid disease in the pediatric population, acknowledging the unique features that this patient group carries and the specific approach it requires.
Extent of Mucosal Inflammation in Ulcerative Colitis Influences the Clinical Remission Induced by Vedolizumab
Authors: Scarozza Patrizio , Marafini Irene , Laudisi Federica , Troncone Edoardo , Schmitt Heike , Lenti Marco Vincenzo , Costa Stefania , Rocchetti Irene , De Cristofaro Elena , Salvatori Silvia , Frezzati Ludovica , Di Sabatino Antonio , Atreya Raja , Neurath Markus F. , Calabrese Emma , Monteleone Giovanni
Published: February 2020

Randomized controlled clinical trials and real-life observations indicate that less than 50% of patients with Crohn’s disease (CD) or ulcerative colitis (UC) respond to vedolizumab, a humanized monoclonal antibody that blocks the α4β7 integrin. Since α4β7-expressing lymphocytes mainly infiltrate the left colon, we assessed whether localization of CD and UC influences vedolizumab-induced remission. One hundred and eighty-one patients (74 CD and 107 UC) receiving vedolizumab in 3 referral centers were retrospectively evaluated for clinical remission at week 14. Demographic and clinical characteristics were compared between remitters and non-responders, and multivariable multinomial analysis was performed to identify predictors of remission. Remission was achieved in 17 CD (23%) and 34 UC (32%) patients, respectively. In CD, localization of the lesions did not influence clinical remission. In UC, the remitters had more frequently a distal/left-sided colitis (21/34, 62%) as compared to the non-responders (9/47, 19%), and extensive colitis was more frequent in the non-responders (38/47, 81%) than in the remitters (13/34, 38%). The multivariable multinomial analysis showed that distal/left-sided colitis was associated with a higher probability of clinical remission while extensive colitis was inversely associated with induction of remission. Data indicate that UC patients with distal or left-sided colitis are more likely to achieve remission than patients with extensive colitis following vedolizumab treatment.
Accuracy of the QIAxcel Automated System for MIRU-VNTR Genotyping of Mycobacterium tuberculosis in Two Limited Resource Settings
Authors: Tafaj Silva , Ghariani Asma , Trovato Alberto , Kapisyzi Perlat , Essalah Leila , Mehiri Emna , Kasmi Gentian , Burazeri Genc , Slim Saidi Leila , Cirillo Daniela Maria
Published: February 2020

Mycobacterial interspersed repetitive units variable number tandem repeat (MIRU-VNTR) typing of Mycobacterium tuberculosis complex (MTBC) isolates, based on 24 loci, is still widely used as the standard for routine molecular surveillance of tuberculosis (TB). QIAxcel system is proposed as an affordable tool that could replace conventional gel electrophoresis and provide high concordance with the reference methods regarding MIRU-VNTR typing of MTBC. We aimed to evaluate the QIAxcel accuracy for allele calling of MIRU-VNTR loci in two regional reference laboratories. A total of 173 DNA were used for the study. Results obtained with QIAxcel were compared to the reference results obtained with an ABI 3730 DNA analyzer. In Albania, the overall agreement with the reference method was 97.92%. A complete agreement result was obtained for 17 loci. In Tunisia, the overall agreement with the reference method was 98.95%. A complete agreement result was obtained for 17 loci. Overall agreement in both centers was 98.43%. In our opinion, use of QIAxcel technology has the potential to be reliable, given an optimized algorithm. Inaccuracies in sizing of long fragments should be solved, especially regarding locus 4052.
Evaluation of Transfer Learning with Deep Convolutional Neural Networks for Screening Osteoporosis in Dental Panoramic Radiographs
Authors: Lee Ki-Sun , Jung Seok-Ki , Ryu Jae-Jun , Shin Sang-Wan , Choi Jinwook
Published: February 2020

Dental panoramic radiographs (DPRs) provide information required to potentially evaluate bone density changes through a textural and morphological feature analysis on a mandible. This study aims to evaluate the discriminating performance of deep convolutional neural networks (CNNs), employed with various transfer learning strategies, on the classification of specific features of osteoporosis in DPRs. For objective labeling, we collected a dataset containing 680 images from different patients who underwent both skeletal bone mineral density and digital panoramic radiographic examinations at the Korea University Ansan Hospital between 2009 and 2018. Four study groups were used to evaluate the impact of various transfer learning strategies on deep CNN models as follows: a basic CNN model with three convolutional layers (CNN3), visual geometry group deep CNN model (VGG-16), transfer learning model from VGG-16 (VGG-16_TF), and fine-tuning with the transfer learning model (VGG-16_TF_FT). The best performing model achieved an overall area under the receiver operating characteristic of 0.858. In this study, transfer learning and fine-tuning improved the performance of a deep CNN for screening osteoporosis in DPR images. In addition, using the gradient-weighted class activation mapping technique, a visual interpretation of the best performing deep CNN model indicated that the model relied on image features in the lower left and right border of the mandibular. This result suggests that deep learning-based assessment of DPR images could be useful and reliable in the automated screening of osteoporosis patients.
Clinical Interventions and All-Cause Mortality of Patients with Chronic Kidney Disease: An Umbrella Systematic Review of Meta-Analyses
Authors: Kim Jong Yeob , Steingroever Johanna , Lee Keum Hwa , Oh Jun , Choi Min Jae , Lee Jiwon , Larkins Nicholas G. , Schaefer Franz , Hong Sung Hwi , Jeong Gwang Hun , Shin Jae Il , Kronbichler Andreas
Published: February 2020

Patients with chronic kidney disease (CKD) have altered physiologic processes, which result in different treatment outcomes compared with the general population. We aimed to systematically evaluate the efficacy of clinical interventions in reducing mortality of patients with CKD. We searched PubMed, MEDLINE, Embase, and Cochrane Database of Systematic Reviews for meta-analyses of randomized controlled trials (RCT) or observational studies (OS) studying the effect of treatment on all-cause mortality of patients with CKD. The credibility assessment was based on the random-effects summary estimate, heterogeneity, 95% prediction intervals, small study effects, excess significance, and credibility ceilings. Ninety-two articles yielded 130 unique meta-analyses. Convincing evidence from OSs supported mortality reduction with three treatments: angiotensin-converting-enzyme inhibitors or angiotensin II receptor blockers for patients not undergoing dialysis, warfarin for patients with atrial fibrillation not undergoing dialysis, and (at short-term) percutaneous coronary intervention compared to coronary artery bypass grafting for dialysis patients. Two treatment comparisons were supported by highly credible evidence from RCTs in terms of all-cause mortality. These were high-flux hemodialysis (HD) versus low-flux HD as a maintenance HD method and statin versus less statin or placebo for patients not undergoing dialysis. Most significant associations identified in OSs failed to be replicated in RCTs. Associations of high credibility from RCTs were in line with current guidelines. Given the heterogeneity of CKD, it seems hard to assume mortality reductions based on findings from OSs.
The Synergic Effects of FDM 3D Printing Parameters on Mechanical Behaviors of Bronze Poly Lactic Acid Composites
Authors: Moradi Mahmoud , Karami Moghadam Mojtaba , Shamsborhan Mahmoud , Bodaghi Mahdi
Published: February 2020

In this paper, the influence of layer thickness (LT), infill percentage (IP), and extruder temperature (ET) on the maximum failure load, thickness, and build time of bronze polylactic acid (Br-PLA) composites 3D printed by the fused deposition modeling (FDM) was investigated via an optimization method. PLA is a thermoplastic aliphatic polyester obtained from renewable sources, such as fermented plant starch, especially made by corn starch. The design of experiment (DOE) approach was used for optimization parameters, and 3D printings were optimized according to the applied statistical analyses to reach the best features. The maximum value of failure load and minimum value of the build time were considered as optimization criteria. Analysis of variance results identified the layer thickness as the main controlled variable for all responses. Optimum solutions were examined by experimental preparation to assess the efficiency of the optimization method. There was a superb compromise among experimental outcomes and predictions of the response surface method, confirming the reliability of predictive models. The optimum setting for fulfilling the first criterion could result in a sample with more than 1021 N maximum failure load. Finally, a comparison of maximum failure from PLA with Br-PLA was studied.
Levels of Diatom Minor Sterols Respond to Changes in Temperature and Salinity
Authors: Jaramillo-Madrid Ana Cristina , Ashworth Justin , Ralph Peter J.
Published: February 2020

Diatoms are a broadly distributed and evolutionarily diversified group of microalgae that produce a diverse range of sterol compounds. Sterols are triterpenoids that play essential roles in membrane-related processes in eukaryotic cells. Some sterol compounds possess bioactivities that promote human health and are currently used as nutraceuticals. The relationship between sterol diversity in diatoms and their acclimation to different environments is not well understood. In this study, we investigated the occurrence of different sterol types across twelve diatom species, as well as the effect of temperature reduction and changes in salinity on the sterol contents of three model diatom species. In the diatoms Thalassiosira pseudonana, Phaeodactylum tricornutum and Chaetoceros muelleri, we found that changes in the relative contents of minor sterols accompanied shifts in temperature and salinity. This may be indicative of acquired adaptive traits in diatom metabolism.
On the Estimation of the Surface Elevation of Regular and Irregular Waves Using the Velocity Field of Bubbles
Authors: Vargas Diana , Jayaratne Ravindra , Mendoza Edgar , Silva Rodolfo
Published: February 2020

This paper describes a new set of experiments focused on estimating time series of the free surface elevation of water (FSEW) from velocities recorded by submerged air bubbles under regular and irregular waves using a low-cost non-intrusive technique. The main purpose is to compute wave heights and periods using time series of velocities recorded at any depth. The velocities were taken from the tracking of a bubble curtain with only one high-speed digital video camera and a bubble generator. These experiments eliminate the need of intrusive instruments while the methodology can also be applied if the free surface is not visible or even if only part of the depth can be recorded. The estimation of the FSEW was successful for regular waves and reasonably accurate for irregular waves. Moreover, the algorithm to reconstruct the FSEW showed better results for larger wave amplitudes.
Healthcare Utilization and Costs after Receiving a Positive BRCA1/2 Result from a Genomic Screening Program
Authors: Hao Jing , Hassen Dina , Manickam Kandamurugu , Murray Michael F. , Hartzel Dustin N. , Hu Yirui , Liu Kunpeng , Rahm Alanna Kulchak , Williams Marc S. , Lazzeri Amanda , Buchanan Adam , Sturm Amy , Snyder Susan R.
Published: February 2020

Population genomic screening has been demonstrated to detect at-risk individuals who would not be clinically identified otherwise. However, there are concerns about the increased utilization of unnecessary services and the associated increase in costs. The objectives of this study are twofold: (1) determine whether there is a difference in healthcare utilization and costs following disclosure of a pathogenic/likely pathogenic (P/LP) BRCA1/2 variant via a genomic screening program, and (2) measure the post-disclosure uptake of National Comprehensive Cancer Network (NCCN) guideline-recommended risk management. We retrospectively reviewed electronic health record (EHR) and billing data from a female population of BRCA1/2 P/LP variant carriers without a personal history of breast or ovarian cancer enrolled in Geisinger’s MyCode genomic screening program with at least a one-year post-disclosure observation period. We identified 59 women for the study cohort out of 50,726 MyCode participants. We found no statistically significant differences in inpatient and outpatient utilization and average total costs between one-year pre- and one-year post-disclosure periods ($18,821 vs. $19,359, p = 0.76). During the first year post-disclosure, 49.2% of women had a genetic counseling visit, 45.8% had a mammography and 32.2% had an MRI. The uptake of mastectomy and oophorectomy was 3.5% and 11.8%, respectively, and 5% of patients received chemoprevention.
RNA Aptamers for a tRNA-Binding Protein from Aeropyrum pernix with Homologous Counterparts Distributed Throughout Evolution
Authors: Ohmori Senri , Wani Marina , Kitabatake Saki , Nakatsugawa Yuka , Ando Tadashi , Umehara Takuya , Tamura Koji
Published: February 2020

In the present in vitro selection study, we isolated and characterized RNA aptamers for a tRNA-binding protein (Trbp) from an extremophile archaeon Aeropyrum pernix. Trbp-like structures are frequently found not only in aminoacyl-tRNA synthetases but also in diverse types of proteins from different organisms. They likely arose early in evolution and have played important roles in evolution through interactions with key RNA structures. RNA aptamers specific for A. pernix Trbp were successfully selected from a pool of RNAs composed of 60 nucleotides, including a random 30-nucleotide region. From the secondary structures, we obtained a shortened sequence composed of 21 nucleotides, of which the 3′-terminal single stranded CA nucleotides are essential for binding. This may be related to the initial evolutionary role of the universal CCA-3′ terminus of tRNA in the interaction with Trbp-like structures.
A Polyaddition Model for the Prebiotic Polymerization of RNA and RNA-Like Polymers
Authors: Spaeth Alex , Hargrave Mason
Published: February 2020

Implicit in the RNA world hypothesis is that prebiotic RNA synthesis, despite occurring in an environment without biochemical catalysts, produced the long RNA polymers which are essential to the formation of life. In order to investigate the prebiotic formation of long RNA polymers, we consider a general solution of functionally identical monomer units that are capable of bonding to form linear polymers by a step-growth process. Under the assumptions that (1) the solution is well-mixed and (2) bonding/unbonding rates are independent of polymerization state, the concentration of each length of polymer follows the geometric Flory-Schulz distribution. We consider the rate dynamics that produce this equilibrium; connect the rate dynamics, Gibbs free energy of bond formation, and the bonding probability; solve the dynamics in closed form for the representative special case of a Flory-Schulz initial condition; and demonstrate the effects of imposing a maximum polymer length. Afterwards, we derive a lower bound on the error introduced by truncation and compare this lower bound to the actual error found in our simulation. Finally, we suggest methods to connect these theoretical predictions to experimental results.
Controlling the Electronic Properties of a Nanoporous Carbon Surface by Modifying the Pores with Alkali Metal Atoms
Authors: Slepchenkov Michael M. , Nefedov Igor S. , Glukhova Olga E.
Published: February 2020

We investigate a process of controlling the electronic properties of a surface of nanoporous carbon glass-like thin films when the surface pores are filled with potassium atoms. The presence of impurities on the surface in the form of chemically adsorbed hydrogen and oxygen atoms, and also in the form of hydroxyl (OH) groups, is taken into account. It is found that even in the presence of impurities, the work function of a carbon nanoporous glass-like film can be reduced by several tenths of an electron volt when the nanopores are filled with potassium atoms. At the same time, almost all potassium atoms are ionized, losing one electron, which passes to the carbon framework of the film. This is due to the nanosizes of the pores in which the electron clouds of the potassium atom interact maximally with the electrons of the carbon framework. As a result, this leads to an improvement in the electrical conductivity and an increase in the electron density at the Fermi level. Thus, we conclude that an increase in the number of nanosized pores on the film surface makes it possible to effectively modify it, providing an effective control of the electronic structure and emission properties.
Crystallographic Evaluation of Susceptibility to Intergranular Corrosion in Austenitic Stainless Steel with Various Degrees of Sensitization
Authors: Fujii Tomoyuki , Furumoto Takaya , Tohgo Keiichiro , Shimamura Yoshinobu
Published: February 2020

This study investigated the susceptibility to intergranular corrosion (IGC) in austenitic stainless steel with various degrees of sensitization (DOSs) from a microstructural viewpoint based on the coincidence site lattice (CSL) model. IGC testing was conducted using oxalic acid and type 304 stainless steel specimens with electrochemical potentiokinetic reactivation (EPR) ratios that varied from 3 to 30%. As a measure of IGC susceptibility, the width of the corroded groove was used. The relationship between IGC susceptibility, grain boundaries (GB) structure, and EPR ratio of the specimens was evaluated. As a result, the IGC susceptibility cannot be characterized using the Σ value, irrespective of the DOS of the specimen. The IGC susceptibility increases with increasing unit cell area of CSL boundaries, which is a measure of the stability of the CSL boundaries, and then levels off. The relationship between the IGC susceptibility and unit cell area is sigmoidal, irrespective of the DOS of the specimen. The sigmoid curve shifts rightward and the upper bound of IGC susceptibility decreases with decreasing DOS of the specimen.
Tire–Road Contact Area on Asphalt Concrete Pavement and Its Relationship with the Skid Resistance
Authors: Yun Di , Hu Liqun , Tang Cheng
Published: February 2020

Sufficient pavement skid resistance is one of the essential factors to ensure traffic safety. The real contact area (Ar) between the tire and road is significant for understanding and improving the skid resistance performance. In this study, the tire–road contact area is measured by squeezing a smooth underside-dyed rubber block into the specimens, using a self-designed fixture mounted on the universal test machine. The three-dimensional (3D) printing technology is used to separate the specimens with multi-scale roughness. Surface texture on 29 AC pavements is obtained by a 3D scanner and qualified by the root-mean-square surface height (Sq), to investigate the impact of pavement texture on the Ar. The skid resistance on 23 AC road sections is measured using the T2GO system, and the pavement texture is recorded, to discuss the influence of the Ar on the skid resistance. The results indicate that the multi-scale roughness rarely affects the measured contact area once the concerned wavelength is less than 0.6 mm. The Ar decreases with the Sq following a power function but has weak correlation with the friction coefficient. This study could provide an in-depth understanding of the tire–road contact and lays a foundation for optimizing the contact-related pavement performance.
Performance of Manganese(III) Acetylacetonate in Solvent-Borne and High-Solid Alkyd Formulations
Authors: Matušková Eliška , Honzíček Jan
Published: February 2020

This paper reports a strong drying activity of manganese(III) acetylacetonate. It is documented on several solvent-borne and high-solid alkyd binders. Solubility problems, which often appear upon application of new primary driers, were overcome by use of dimethyl sulfoxide. Interestingly, intense coloration of the drier does not influence the transparent paint films due to in situ reduction to manganese(II) as evidenced by colorimetric measurements. Kinetics of the autoxidation process was investigated by infrared and Raman spectroscopy. For selected formulation, the effect of film thickness on through drying was estimated by infrared spectroscopy using attenuated total reflection sampling technique.
In Situ Microgravimetric Study of Ion Exchanges in the Ternary Cu-In-S System Prepared by Atomic Layer Deposition
Authors: Le Tulzo Harold , Schneider Nathanaelle , Donsanti Frédérique
Published: February 2020

Reaction mechanisms during the growth of multinary compounds by atomic layer deposition can be complex, especially for sulfide materials. For instance, the deposition of copper indium disulfide (CuInS2) shows a non-direct correlation between the cycle ratio, the growth per cycle of each binary growth cycles, i.e., CuxS and In2S3, and the film composition. This evidences side reactions that compete with the direct Atomic Layer Deposition (ALD) growth reactions and makes the deposition of large films very challenging. To develop a robust upscalable recipe, it is essential to understand the chemical surface reactions. In this study, reaction mechanisms in the Cu-In-S ternary system were investigated in-situ by using a quartz crystal microbalance system to monitor mass variations. Pure binary indium sulfide (In2S3) and copper sulfide (CuxS) thin film depositions on Al2O3 substrate were first studied. Then, precursors were transported to react on CuxS and In2S3 substrates. In this paper, gas-phase ion exchanges are discussed based on the recorded mass variations. A cation exchange between the copper precursor and the In2S3 is highlighted, and a solution to reduce it by controlling the thickness deposited for each stack of binary materials during the CuInS2 deposition is finally proposed.
Mechanobiological Approach to Design and Optimize Bone Tissue Scaffolds 3D Printed with Fused Deposition Modeling: A Feasibility Study
Authors: Percoco Gianluca , Uva Antonio Emmanuele , Fiorentino Michele , Gattullo Michele , Manghisi Vito Modesto , Boccaccio Antonio
Published: February 2020

In spite of the rather large use of the fused deposition modeling (FDM) technique for the fabrication of scaffolds, no studies are reported in the literature that optimize the geometry of such scaffold types based on mechanobiological criteria. We implemented a mechanobiology-based optimization algorithm to determine the optimal distance between the strands in cylindrical scaffolds subjected to compression. The optimized scaffolds were then 3D printed with the FDM technique and successively measured. We found that the difference between the optimized distances and the average measured ones never exceeded 8.27% of the optimized distance. However, we found that large fabrication errors are made on the filament diameter when the filament diameter to be realized differs significantly with respect to the diameter of the nozzle utilized for the extrusion. This feasibility study demonstrated that the FDM technique is suitable to build accurate scaffold samples only in the cases where the strand diameter is close to the nozzle diameter. Conversely, when a large difference exists, large fabrication errors can be committed on the diameter of the filaments. In general, the scaffolds realized with the FDM technique were predicted to stimulate the formation of amounts of bone smaller than those that can be obtained with other regular beam-based scaffolds.
Lab and Pilot-Scale Synthesis of MxOm@SiC Core–Shell Nanoparticles
Authors: Ribes Àngela , Sánchez-Cabezas Santiago , Hernández-Montoto Andy , Villaescusa Luis A. , Aznar Elena , Martínez-Máñez Ramón , Marcos M. Dolores , López-Tendero M. José , Pradas Sarai , Cuenca-Bustos Alejandro
Published: February 2020

The addition of light ceramic particles to bulk technological materials as reinforcement to improve their mechanical properties has attracted increasing interest in the last years. The metal matrix composites obtained using nanoparticles have been reported to exhibit an improvement of their properties due to the decrease in the size of the ceramic additives to the nanoscale. Additionally, important effects such as the dispersion of the nanoparticles, wettability, and low reactivity can be controlled by the modification of the nanoparticles’ surface. In this work, we present the preparation of core–shell MxOm@SiC nanoparticles with different shell compositions. The accurate and reproducible preparation is developed both at the lab and pilot scale. The synthesis of these core–shell nanoparticles and their scale-up production are fundamental steps for their industrial use as additives in metal matrix composites and alloys. Powder X-ray diffraction and energy dispersive X-ray (EDX) coupled with scanning transmission electron microscopy (STEM) are used to corroborate the formation of the core–shell systems, whereas line scan-EDX analysis allows measuring the average shell thickness.
Seleninic Acid Potassium Salts as Water-Soluble Biocatalysts with Enhanced Bioavailability
Authors: Obieziurska Magdalena , Pacuła Agata J. , Laskowska Anna , Długosz-Pokorska Angelika , Janecka Anna , Ścianowski Jacek
Published: February 2020

Organoselenium compounds are well-known glutathione peroxidase (GPx) mimetics that possess antioxidants/prooxidant properties and are able to modulate the concentration of reactive oxygen species (ROS), preventing oxidative stress in normal cells or inducing ROS formation in cancer cells leading to apoptosis. The purpose of this study was the synthesis of potent GPx mimics with antioxidant and anticancer activity along with improved bioavailability, as a result of good solubility in protic solvents. As a result of our research, glutathione peroxidase (GPx) mimetics in the form of water-soluble benzeneseleninic acid salts were obtained. The procedure was based on the synthesis of 2-(N-alkylcarboxyamido)benzeneselenenic acids, through the oxidation of benzisoselenazol-3(2H)-ones or analogous arenediselenides with an amido group, which were further converted to corresponding potassium salts by the treatment with potassium tert-butanolate. All derivatives were tested as potential antioxidants and anticancer agents. The areneseleninic acid salts were significantly better peroxide scavengers than analogous acids and the well-known organoselenium antioxidant ebselen. The highest activity was observed for the 2-(N-ethylcarboxyamido)benzeneselenenic acid potassium salt. The strongest cytotoxic effect against breast cancer (MCF-7) and human promyelocytic leukemia (HL-60) cell lines was found for 2-(N-cyclohexylcarboxyamido)benzeneselenenic acid potassium salt and the 2-(N-ethylcarboxyamido)benzeneselenenic acid, respectively. The structure–activity correlations, including the differences in reactivity of benzeneseleninic acids and corresponding salts were evaluated.
Magnetoelastic Coupled Wave Diffraction and Dynamic Stress Intensity Factor in Graded Piezomagnetic Composites with a Cylindrical Aperture
Authors: Jiang Yinhuan , Zhou Chuanping , Wang Ban , Wu Liqun
Published: February 2020

A theoretical method is developed to study the magnetoelastic coupled wave and dynamic stress intensity around a cylindrical aperture in exponential graded piezomagnetic materials. By employing the decoupling technique, the coupled magnetoelastic governing equations are decomposed. Then the analytic solutions of elastic wave fields and magnetic fields are presented by using the wave function expansion method. By satisfying the boundary conditions of the aperture, the mode coefficients, and the analytic solutions of dynamic stress intensity factors are determined. The numerical examples of the dynamic stress intensity factor near the aperture are presented. The numerical results indicate that the incident wave number, the piezomagnetic properties, and the nonhomogeneous parameter of materials highly influence the dynamic stress around the aperture.
Study of Mild Steel Sandwich Structure Energy Absorption Performance Subjected to Localized Impulsive Loading
Authors: Alqwasmi Nouman , Tarlochan Faris , Alkhatib Sami E.
Published: February 2020

Extensive research focus had been given to sacrificial sandwich panels to mitigate the effects of blast loads. This is due to their ability to distribute the load and absorb a significant portion of the blast energy. This paper studies the behavior of sacrificial sandwich mild steel panels of axially oriented octagonal tapered tubular cores subjected to near-field impulsive blast. The deformation behavior and several assessment parameters consisting of the peak force, stroke efficiency, energy absorption and core efficiency were investigated using validated finite element analysis. The developed deformation modes were mainly influenced by the top plate and tube thickness. Tubes of a 5° taper performed unfavorably, exhibiting increased peak force and lower energy absorption. Panels of top plate thickness of 4 mm exhibited higher stroke efficiency as compared to panels of lower thickness. The top plate and tube thickness significantly affected energy absorption. An increase of 73.5% in core efficiency was observed in thick-plate panels as compared to thin-plate ones.
Mechanical Properties and Thermal Conductivity of Ytterbium-Silicate-Mullite Composites
Authors: Xiao Jie , Chen Wenbo , Wei Liangliang , He Wenting , Guo Hongbo
Published: February 2020

Various Ytterbium-Silicate-Mullite composites were successfully fabricated by adding Yb2SiO5 into mullite ceramics and then using pressureless sintering at 1550 °C. The influence of Yb2SiO5 addition on the microstructure, mechanical properties, and thermal conductivity of ytterbium-silicate-mullite composites was investigated. Results show that the composites mainly consisted of a mullite matrix and some in situ formed Yb2Si2O7 and Al2O3 phases. By the addition of Yb2SiO5, the Vickers hardness of composites reached ~9.0 at an additive concentration of 5 mol %. Fracture toughness increased to ~2.7 MPa·m1/2 at the additive concentration of 15 mol %, owing to the trans-granular fracture and crack deflection of the pinning effect of the Al2O3 phase in the composites. With the increase of the Al2O3 phase in the composite, the thermal conductivity for the 15YbAM reached around 4.0 W/(m·K) at 1200 °C. Although the thermal conductivity increased, it is still acceptable for such composites to be used as environmental barrier coatings.
Investigation of a Short Carbon Fibre-Reinforced Polyamide and Comparison of Two Manufacturing Processes: Fused Deposition Modelling (FDM) and Polymer Injection Moulding (PIM)
Authors: Verdejo de Toro Elena , Coello Sobrino Juana , Martínez Martínez Alberto , Miguel Eguía Valentín , Ayllón Pérez Jorge
Published: February 2020

New technologies are offering progressively more effective alternatives to traditional ones. Additive Manufacturing (AM) is gaining importance in fields related to design, manufacturing, engineering and medicine, especially in applications which require complex geometries. Fused Deposition Modelling (FDM) is framed within AM as a technology in which, due to their layer-by-layer deposition, thermoplastic polymers are used for manufacturing parts with a high degree of accuracy and minimum material waste during the process. The traditional technology corresponding to FDM is Polymer Injection Moulding, in which polymeric pellets are injected by pressure into a mould using the required geometry. The increasing use of PA6 in Additive Manufacturing makes it necessary to study the possibility of replacing certain parts manufactured by injection moulding with those created using FDM. In this work, PA6 was selected due to its higher mechanical properties in comparison with PA12. Moreover, its higher melting point has been a limitation for 3D printing technology, and a further study of composites made of PA6 using 3D printing processes is needed. Nevertheless, analysis of the mechanical response of standardised samples and the influence of the manufacturing process on the polyamide’s mechanical properties needs to be carried out. In this work, a comparative study between the two processes was conducted, and conclusions were drawn from an engineering perspective.
The Influence of the Size and Oxidation Degree of Graphene Flakes on the Process of Creating 3D Structures during Its Cross-Linking
Authors: Kaczmarek Łukasz , Warga Tomasz , Makowicz Magdalena , Kyzioł Karol , Bucholc Bartosz , Majchrzycki Łukasz
Published: February 2020

This article presents the results of the cross-linking of oxidized flake graphene (GO) using hydrazine at room temperature. Conducting the process at temperatures up to 30 °C allowed to eliminate the phenomenon of thermal GO reduction to its non-oxidized form. In addition, based on the Infrared and Raman spectroscopy as well as X-ray photoelectron spectroscopy (XPS) analysis, the cross-linking ability of GO was observed depending on its size and degree of oxidation. These parameters were associated with selected physicochemical and electrical properties of obtained 3D structures. Three GO flakes sizes were tested in three different oxidation degrees. It was shown that, regardless of the size of GO, it is crucial to achieve a specific oxidation degree threshold which for the conducted tests was a >20% share of oxygen atoms in the whole structure. This value determines the ability to cross-link with hydrazine thanks to which it is possible to synthesize the spatial structure in which the π–π interactions among individual flakes are significantly reduced. This directly translates into the fact that the 3D structure shows an electrical resistance value in the range of 4–103 Ω, depending on the size and oxidation degree of the used material. The explanation of this phenomenon related to the electrical conductivity of 3D structures was confirmed based on the molecular modeling of the chemical structures.
Effects of Steel Slag Powder and Expansive Agent on the Properties of Ultra-High Performance Concrete (UHPC): Based on a Case Study
Authors: Li Shunkai , Cheng Shukai , Mo Liwu , Deng Min
Published: February 2020

In view of the performance requirements of mass ultra-high performance concrete (UHPC) for the Pang Gong bridge steel cable tower in China, the UHPC incorporating of steel slag powder and hybrid expansive agents is optimized and prepared. The effects of steel slag powder and hybrid expansive agents on the hydration characteristics and persistent shrinkage of UHPC are investigated. The results indicate that 15 wt.% steel slag powder and 5 wt.% hybrid expansive agents can effectively reduce the drying shrinkage deformation of UHPC with a slight decrease of strength. Heat flow calorimetry results show that the incorporation of steel slag powder and expansive agents decreases the hydration heat at three days. Moreover, the obtained adiabatic temperature rise of UHPC is 59.5 °C and the total shrinkage value at 180 days is 286 με. The hydration heat release changes of large volume UHPC in the steel-concrete section of cable tower is agreed with the result of adiabatic temperature rise in the laboratory.
Faber Polynomial Coefficient Estimates for Bi-Univalent Functions Defined by Using Differential Subordination and a Certain Fractional Derivative Operator
Authors: Srivastava Hari M. , Motamednezhad Ahmad , Adegani Ebrahim Analouei
Published: February 2020

In this article, we introduce a general family of analytic and bi-univalent functions in the open unit disk, which is defined by applying the principle of differential subordination between analytic functions and the Tremblay fractional derivative operator. The upper bounds for the general coefficients | a n | of functions in this subclass are found by using the Faber polynomial expansion. We have thereby generalized and improved some of the previously published results.
The Extinction of a Non-Autonomous Allelopathic Phytoplankton Model with Nonlinear Inter-Inhibition Terms and Feedback Controls
Authors: Zhao Liang , Chen Fengde , Song Saixi , Xuan Guizhen
Published: February 2020

A non-autonomous allelopathic phytoplankton model with nonlinear inter-inhibition terms and feedback controls is studied in this paper. Based on the comparison theorem of differential equation, some sufficient conditions for the permanence of the system are obtained. We study the extinction of one of the species by using some suitable Lyapunov type extinction function. Our analyses extend those of Xie et al. (Extinction of a two species competitive system with nonlinear inter-inhibition terms and one toxin producing phytoplankton. Advances in Difference Equations, 2016, 2016, 258) and show that the feedback controls and toxic substances have no effect on the permanence of the system but play a crucial role on the extinction of the system. Some known results are extended.
Separation Axioms of Interval-Valued Fuzzy Soft Topology via Quasi-Neighborhood Structure
Authors: Ali Mabruka , Kılıçman Adem , Zahedi Khameneh Azadeh
Published: February 2020

In this study, we present the concept of the interval-valued fuzzy soft point and then introduce the notions of its neighborhood and quasi-neighborhood in interval-valued fuzzy soft topological spaces. Separation axioms in an interval-valued fuzzy soft topology, so-called q- T i for i = 0 , 1 , 2 , 3 , 4 , are introduced, and some of their basic properties are also studied.
Eigenvalue Problem for Discrete Jacobi–Sobolev Orthogonal Polynomials
Authors: Mañas-Mañas Juan F. , Moreno-Balcázar Juan J. , Wellman Richard
Published: February 2020

In this paper, we consider a discrete Sobolev inner product involving the Jacobi weight with a twofold objective. On the one hand, since the orthonormal polynomials with respect to this inner product are eigenfunctions of a certain differential operator, we are interested in the corresponding eigenvalues, more exactly, in their asymptotic behavior. Thus, we can determine a limit value which links this asymptotic behavior and the uniform norm of the orthonormal polynomials in a logarithmic scale. This value appears in the theory of reproducing kernel Hilbert spaces. On the other hand, we tackle a more general case than the one considered in the literature previously.
Ideal and Predictable Hit Ratio for Matrix Transposition in Data Caches
Authors: Pedro-Zapater Alba , Rodríguez Clemente , Segarra Juan , Gran Tejero Rubén , Viñals-Yúfera Víctor
Published: February 2020

Matrix transposition is a fundamental operation, but it may present a very low and hardly predictable data cache hit ratio for large matrices. Safe (worst-case) hit ratio predictability is required in real-time systems. In this paper, we obtain the relations among the cache parameters that guarantee the ideal (predictable) data hit ratio assuming a Least-Recently-Used (LRU) data cache. Considering our analytical assessments, we compare a tiling matrix transposition to a cache oblivious algorithm, modified with phantom padding to improve its data hit ratio. Our results show that, with an adequate tile size, the tiling version results in an equal or better data hit ratio. We also analyze the energy consumption and execution time of matrix transposition on real hardware with pseudo-LRU (PLRU) caches. Our analytical hit/miss assessment enables the usage of a data cache for matrix transposition in real-time systems, since the number of misses in the worst case is bound. In general and high-performance computation, our analysis enables us to restrict the cache resources devoted to matrix transposition with no negative impact, in order to reduce both the energy consumption and the pollution to other computations.
Asymptotically Convergent Higher-Order Switching Differentiator
Authors: Park Jang-Hyun , Park Tae-Sik , Kim Seong-Hwan
Published: February 2020

A novel switching-differentiator (SD) that can asymptotically track the time derivative of time-varying signal was previously proposed. This paper extends the previous SD to estimation of higher-order time derivatives. This study shows that higher-order time-derivatives can be estimated by connecting multiple SDs in cascade form. By successive applying the generalized Barbalat’s lemma, all higher-order tracking errors also approach zeros asymptotically. To illustrate the performance of the proposed higher-order switching differentiator, simulations were performed for estimating higher-order time-derivatives of a signal.
Application of Zr and Ti-Based Bulk Metallic Glasses for Orthopaedic and Dental Device Materials
Authors: Imai Kazuhiro , Zhou Xiao , Liu Xiaoxuan
Published: February 2020

Conventional orthopaedic and dental device materials are made of metallic materials such as stainless steel (SUS316L), titanium alloy (Ti-6Al-4V), and cobalt-chrome (Co-Cr). Those materials have the disadvantage of mechanical properties and anti-corrosion behavior. Bulk metallic glasses (BMGs), which are also called amorphous alloys, are metallic materials with metastable glassy states and have a higher strength, higher elasticity, higher failure resistance, and lower Young’s modulus compared with crystalline alloys. There are several types of BMGs. Among them, Zr-based BMGs and Ti-based BMGs have excellent mechanical properties. In addition, they have good corrosion resistance and are promising for orthopaedic and dental device materials. In this review article, in vitro and in vivo studies regarding Zr and Ti-based BMGs applications as biomaterials, especially in orthopaedic and dental device materials, are reviewed.
Evaluation of the DOS by DL−EPR of UNSM Processed Inconel 718
Authors: Martin Ulises , Ress Jacob , Bosch Juan , Bastidas David M.
Published: February 2020

In this work, influence of ultrasonic nanocrystal surface modification (UNSM) on the degree of sensitization (DOS) in Inconel 718 has been studied and correlated with the resulting microstructure. The UNSM processed samples decreased their grain size from 11.9 µm to 7.75 µm, increasing the surface of grain boundaries, and thus enhancing the area where δ phase and niobium carbides precipitate. The effect of the UNSM process on the DOS of Inconel 718 was studied by the double loop electrochemical potentiokinetic reactivation (DL−EPR) test. The DL−EPR showed that for UNSM processed samples with no thermal treatment, the DOS increased up to 59.6%, while for UNSM treated samples that were post-annealed at 1000 °C for 10 min and water quenched the DOS decreased down to 40.9%. The increase of grain boundaries surface area and triple junctions after the UNSM process enables the formation of twice the amount of δ phase compared to the as-received Inconel 718 bulk sample. The area fraction of the grain boundary covered by δ phase was of 9.87% in the UNSM region while in the bulk the area fraction was 4.09%. In summary, it was found that after UNSM process, the annealing at 1000 °C for 10 min and water quenching promoted the transformation of γ″ to form δ phase on the grain boundaries, which reduces the intergranular corrosion susceptibility.