bluuebunny/crossref_metadata_2025_split huggingface dataset:
Elementary teachers' perceptions of K‐5 engineering education and perceived barriers to implementation
Authors: Hammack Rebekah , Ivey Toni 
Published: October 2019

AbstractBackgroundThe Next Generation Science Standards (NGSS) call for the integration of engineering content and practices in elementary science curricula, yet little is known about elementary teachers' preparedness to do so or their views on teaching engineering.Purpose/HypothesisThe purpose of the current study was to explore K‐5 teachers' perceptions about incorporating engineering in their classrooms as well as the perceived barriers for doing so.Design/MethodThis study consisted of an online survey including a mix of selected response, Likert, and short answer items, followed by individual interviews and focus group sessions with a subset of survey participants. Descriptive statistics are reported for quantitative survey data. Open‐ended survey questions as well as interview and focus group transcripts were inductively coded to identify emergent themes.ResultsMany elementary teachers support the inclusion of engineering in the science standards for elementary grades. Teachers describe a lack of preservice and in‐service training, background knowledge, materials, time for planning and implementing lessons, and administrative support as barriers to implementing engineering activities within their classrooms.ConclusionWhile many elementary teachers support the use of engineering activities in their classrooms, there are numerous barriers preventing them from doing so. To ensure that NGSS are incorporated into elementary classrooms as they were intended, elementary teachers must be provided with the necessary training, resources, and support.
Spectroscopic characterization of glycidyl methacrylate with acrylonitrile copolymers and monomer reactivity ratios
Authors: Soykan Cengiz , Obuz Hilal 
Published: October 2019

AbstractWe report herein that copolymers containing glycidyl methacrylate (GMA) with acrylonitrile (AN) units were synthesized by free radical solution polymerization technique using benzoyl peroxide as a free radical initiator and 1,4‐dioxane as a solvent at 70°C. The copolymerization behavior was studied in different composition with the mole fractions of GMA ranging from 0.20 to 0.80 in the feed and under 10% copolymer conversion. The copolymers were characterized by Fourier transform infrared spectroscopy, gel permeation chromatography, and scanning electron microscopy techniques. The thermogravimetric analysis of the copolymers suggest an overall decrease in the thermal stability of the copolymer with decreasing content of GMA in the copolymers. Thermal decomposition activation energies are calculated by the Ozawa method. The copolymer composition was determined by the application of elemental analysis method. The monomer reactivity ratios were estimated by the application of conventional linearization methods, such as Kelen–Tudos (K‐T), Fineman–Ross (F‐R) methods, and a nonlinear error in variable model (RREVM) method using a computer program, and all results were discussed and compared with the literature.
Cyclic fatigue life of novel rotary compactors: A scanning electron microscopy evaluation
Authors: Orhan Ekim O. , Ertuğrul İhsan F. 
Published: October 2019

AbstractThe aim was to investigate the cyclic fatigue life of two novel rotary compactors produced for MTA compaction and produced for gutta‐percha compaction. Two‐type of nickel‐titanium rotary compactors were used (n = 20). A static model was preferred for this study due to simulating the clinical application of compaction and to obtain a baseline repository data of this type of instruments. OrthoMTA Compacter (25/0.02) and Revo Condensor (30/0.04) instruments were operated speed of 250 and 4,800 rpm, respectively at 35°C until fracture occurred. The time to fracture was recorded, and the length of the fractured fragments was registered. The independent t‐test was performed (p < .05). The fractured instruments were evaluated with a high‐resolution field emission scanning electron microscope to allow visualization of the surfaces under several magnifications (×100 and ×10,000). OrthoMTA Compacter (3679.27 NCF), was extremely different in the mean number of cycles to failure when compared with Revo Condensor (1269.48 NCF) (p < .0001). The mean length of the fractured tip of OrthoMTA Compacter and Revo Condensor were 4.87 mm and 4.51, respectively (p < .0001). The surfaces of the instruments shown typical features of cyclic fatigue failure, involving crack origins, fatigue regions, and an overload region. This is the first study in the literature to date evaluating the cyclic fatigue life of Revo Condensor and OrthoMTA Compacter. OrthoMTA Compacter presented higher cyclic fatigue life compared with Revo Condensor.
Many roads lead to Rome: Neutral phenotypes in microorganisms
Authors: Nanjundiah Vidyanand 
Published: October 2019

AbstractJohn Bonner pointed out that microorganisms differ in several ways, some of which may reflect neutral phenotypic evolution. For making his case, Bonner referred to interspecies differences and morphological traits. Here we consider intraspecies differences and physiological traits. As a case‐study, we examine the production of an extracellular cyclic 3,5 monophosphate phosphodiesterase in the cellular slime mold Dictyostelium discoideum. Temporal profiles of phosphodiesterase activity differ significantly between wild‐type strains. From that we argue that the inference drawn initially from studies on a single wild‐type, namely that the profile displayed by it pointed to an adaptive role, was mistaken. We generalize the conclusion to suggest that physiological differences exhibited by microorganisms of the same species may, but need not, reflect adaptations to different environments. Rather, the differences could be related to the fact that microorganisms live in groups whose composition can vary between homogeneous (clonal) and heterogeneous (polyclonal). More than one physiological profile is consistent with the normal development of the group in a given environment; the alternatives are neutral. When studying microbial physiology and behavior, it is expected that the observations are made on a clonal population; genetic (and so phenotypic) heterogeneity is carefully guarded against. As the example from D. discoideum shows, an unintended consequence of overlooking phenotypic heterogeneity is that one can fall into the trap of accepting a seemingly plausible, but possibly erroneous, adaptive explanation for a “normal” wild‐type phenotype.
Synthesis and characterization of active cuprous oxide particles and their catalytic application in 1,2,3‐triazole synthesis via alkyne‐azide cycloaddition reaction in water
Authors: Sawkmie Micky Lanster , Paul Dipankar , Kalita Gitumoni , Agarwala Khushboo , Maji Pradip K. , Chatterjee Paresh Nath 
Published: October 2019

AbstractActive cuprous oxide materials are synthesized from CuSO4.5H2O using sodium stannite as reducing agent in the presence of various stabilizers, viz., cetyl trimethyl ammonium bromide, sodium dodecyl sulphate, and polyvinyl pyrrolidone. The synthesized cuprous oxide materials are well characterized by powder X‐ray diffraction and Fourier transform infrared spectroscopy to ascertain their identity, while field emission scanning electron microscopy and energy‐dispersive spectroscopy analysis were used to study their morphology and composition, respectively. We have compared the catalytic prowess of the various cuprous oxide materials in the cycloaddition reaction of alkynes and azides to synthesize 1,4‐disubstituted‐1,2,3‐triazoles. A wide variety of substitutions can nicely be tolerated in our optimized reaction conditions to produce very good to excellent yields of the corresponding triazoles in water at 55 °C. The reactions are carried out in water without any assistance of organic cosolvent or other additives, which renders the catalytic method as economical and environment friendly.
Anti-streptococcal antibody and T-cell interactions with vascular endothelial cells initiate the development of rheumatic carditis
Authors: Sikder Suchandan , Rush Catherine M. , Govan Brenda L. , Alim Md A. , Ketheesan Natkunam 
Published: October 2019

Abstract
The role of group A streptococcal and Streptococcus dysgalactiae subspecies equisimilis M-protein specific Abs and T-cells in endothelial cell activation was investigated using cultured rat aortic endothelial cells, and in a rat model of autoimmune valvulitis. Heat inactivated serum and mononuclear cells from streptococcal M-protein immunized rats independently induced upregulation of the endothelial cell adhesion molecules, vascular cell adhesion molecule (VCAM)-1 and intercellular adhesion molecule (ICAM)-1 in cultured cells. We also observed T-cell migration across endothelial cell monolayers incubated with serum from M-protein-immunized rats. Furthermore, we observed VCAM-1 and ICAM-1 expression in the myocardium of rats injected with M-protein compared to control animals. These observations support the contention that initial interactions between streptococcal M-protein specific Abs and/or T-cells with the heart endothelium lead to endothelial cell activation followed by transmigration of M-protein specific T-cells into heart tissue leading to an inflammatory process that leads to carditis in rheumatic fever and rheumatic heart disease.
A novel TDFEM scheme based on high‐performance parallel solver PaStiX
Authors: Wu Xia 
Published: October 2019

AbstractIn this paper, we focus on the theory and fulfillment of parallel time domain finite element method (TDFEM) with PaStiX (Parallel Sparse matriX package) for solving three‐dimensional electromagnetic (EM) radiation problems. The motivation behind the research is required to maintain numerical stability and achieve high speed for parallel sparse LU factorization on parallel platforms. Firstly, we overview the concept of an unconditional stable TDFEM scheme, and numerical optimization for ill‐conditioned equations obtained from the TDFEM with perfectly matched layer (PML) was presented to alleviate nonconvergent results. Secondly, we develop sparse linear system solvers that use DS factorization to solve the preconditioned system. Numerical results were obtained from the cases of the cavity resonance problem and a cone antenna. A noteworthy observation from the time‐consuming results in different solvers is that PaStiX is usually much faster compared with UMFPACK and SuperLU.
Solid acids assisted matrix solid‐phase dispersion microextraction of alkaloids by capillary electrophoresis coupled with quadrupole time‐of‐flight mass spectrometry
Authors: Wang Qiu‐Yan , Dong Xin , Yang Juan , Zhen Xiao‐Ting , Ye Li‐Hong , Chu Chu , Wang Bin , Hu Yu‐Han , Zheng Hui , Cao Jun 
Published: October 2019

AbstractThe quantification of three alkaloids is important because quantitative study is a means of assessing the reliability of the experimental method, and three alkaloids of peimine, peiminine, and peimisine are main active ingredients in Chinese Pharmacopoeia 2015. An effective method based on the matrix solid‐phase dispersion microextraction was developed for the extraction of alkaloid compounds in Fritillariae Thunbergii Bulbus. Target analytes were analyzed by capillary electrophoresis coupled with quadrupole time‐of‐flight mass spectrometry. The optimized experimental condition was that 50 mg Fritillariae Thunbergii Bulbus was blended homogeneously with 10 mg citric acid for 5 min. Two hundred microliters of water acidized by 1 mol/L hydrochloric acid (pH = 4.5) was selected to elute tested alkaloids. The results demonstrated that the investigated method had low limits of detection (1.32–1.59 ng/mL), good recoveries (86.63–98.12%), and reproducibility (relative standard deviations of peak areas < 0.87%). The proposed matrix solid‐phase dispersion microextraction coupled with capillary electrophoresis combined with quadrupole time‐of‐flight mass spectrometry was successfully applied for the extraction of alkaloids in plants.
Correlation Between Endorectal Ultrasound and Magnetic Resonance Imaging for Predicting the Circumferential Resection Margin in Patients With Mid‐Low Rectal Cancer Without Preoperative Chemoradiotherapy
Authors: Ye Dalin , Zhu Zhimin , Chen Fei , Lie Chaowei , Li Wenlu , Lin Yunyong , Qiu Shaodong 
Published: October 2019

ObjectivesTo assess the correlation between endorectal ultrasound (ERUS) and magnetic resonance imaging (MRI) in predicting the circumferential resection margin (CRM) status of patients with mid‐low rectal cancer without preoperative chemoradiotherapy.MethodsTwenty patients with rectal cancer who did not receive preoperative chemoradiotherapy and underwent ERUS and MRI examinations before total mesorectal excision from May 2018 to April 2019 were included in this study. The patient and tumor characteristics, lymph nodes, tumor stages, ERUS and MRI predictors of the CRM status, and postoperative pathologic results were recorded. The closest distance between the deepest portion of lesion invasion and the mesorectal fascia was independently measured on MRI and ERUS images by 2 observers. The observers were blinded to the pathologic results. Measurements from ERUS and MRI were compared.ResultsThe mean distance between the distal edge of the lesion and the anal verge was 5.7 cm (range, 3.1–8.1 cm). The ERUS and pathologic evaluations of CRM involvement were consistent in 90% of the cases. The MRI and pathologic evaluations of CRM involvement were concordant in 95% of the cases. The Cohen κ coefficient of ERUS and MRI was 0.608 (P = .007). The correlation coefficient of ERUS and MRI for assessing the closest distance from the edge of cancer invasion to the mesorectal fascia was 0.99 (P = .0005).ConclusionsEndorectal ultrasound and MRI assessments of the preoperative CRM status appear to be highly consistent. Endorectal ultrasound can be used as a complementary tool with MRI to predict the CRM status of patients with mid‐low rectal cancer without preoperative chemoradiotherapy.
The performance improvement of visible light communication systems under strong nonlinearities based on Gaussian mixture model
Authors: Wu Xingbang , Hu Fangchen , Zou Peng , Lu Xingyu , Chi Nan 
Published: October 2019

AbstractNonlinearity is a major problem in visible light communication (VLC). In recent years, machine learning has emerged and has been widely used in many fields. Among them, the nonlinear algorithms have gradually become a powerful tool to solve the nonlinearity in VLC. In this article, we compare the performance of two main clustering algorithms—Gaussian mixture model (GMM) and K‐means under strong nonlinear conditions. Experimental results show that the signal peak‐to‐peak voltage (Vpp)r range is approximately 0.25 V that meets the BER threshold of forward error correction when using GMM and is larger than the range using K‐means under the data rate is 1.5 Gbps.
Transient analysis of full‐space unbounded domains by reciprocal absorbing boundaries
Authors: Nguyen Cuong T. , Tassoulas John L. 
Published: October 2019

SummaryIn this paper, we explore a combination of the reciprocal absorbing boundary condition with perfectly matched discrete layers for the time‐domain analysis of wave motion in the full plane. Coupling of these absorbing boundaries leads to solutions for out‐of‐plane as well as in‐plane excitations of the full plane. Together with numerical transient simulations, harmonic analysis is also carried out for the purpose of verifying the results by comparing with available exact frequency‐domain solutions. The proposed combination is investigated through several numerical examples, which demonstrate its accuracy and efficiency.
Children's self‐reports of fear and pain levels during needle procedures
Authors: Hedén Lena , von Essen Louise , Ljungman Gustaf 
Published: October 2019

AbstractAimThe objective was to determine the levels of and potential relationships between, procedure‐related fear and pain in children.DesignClinical based cross‐sectional.MethodsNinety children aged between 7–18 years were included consecutively and self‐reported levels of pain and fear on a 0–100 mm visual analogue scales (VAS) when undergoing routine needle insertion into a subcutaneously implanted intravenous port following topical anaesthesia.ResultsThe needle‐related fear level was reported to be as high as the needle‐related pain level (mean VAS: 14 mm and 12 mm, respectively, N = 90). With fear as the dependent variable, age and pain were significantly associated and explained 16% of the variance. With pain as the dependent variable, fear was significantly associated and explained 11% of the variance. A post hoc analysis indicated that younger children reported their fear levels to be higher than their pain levels.
Challenging the indiscriminate use of temozolomide in pediatric high‐grade gliomas: A review of past, current, and emerging therapies
Authors: Guerra‐García Pilar , Marshall Lynley V. , Cockle Julia V. , Ramachandran Purushotham V. , Saran Frank H. , Jones Chris , Carceller Fernando 
Published: October 2019

AbstractPediatric high‐grade gliomas (pHGG) constitute 8% to 12% of primary brain tumors in childhood. The most widely utilized treatment encompasses surgical resection followed by focal radiotherapy and temozolomide. However, experiences over past decades have not demonstrated improved outcomes. pHGG have been classified into different molecular subgroups defined by mutations in histone 3, IDH gene, MAPK pathway, and others, thereby providing a rationale for various targeted therapies. Additionally, immunotherapy and drug repurposing have also become attractive adjunctive treatments. This review focuses on past, present, and emerging treatments for pHGG integrating molecular research with the mainstream pediatric drug development in Europe and the United States to sketch a way forward in the development of novel therapeutic approaches. The implementation of randomized clinical trials with adaptive designs, underpinned by a robust biological rationale, and harnessing collaboration between the pharmaceutical industry, academia, regulators and patients/parents organizations will be essential to improve the outcomes for these children.
Significantly enhanced thermal conductivity in polyimide composites with the matching of graphene flakes and aluminum nitride by in situ polymerization
Authors: He Xuhua , Yu Xin , Wang Yuechuan 
Published: October 2019

AbstractHighly thermally conductive polymer composites are urgently required for effective heat dissipation in advanced electronic devices. Rational matching of thermal conductive fillers and proper preparation method are important for obtaining a highly thermally conductive composites at low filler content. Here we report polyimide (PI) composites filled with graphene flakes (GF) and polyhedral aluminum nitride (AlN), which simultaneously exhibit high thermal conductivity, improved thermal mechanical properties, and excellent thermal stability. PI composite films were readily prepared by in situ polymerization at the presence of fillers that are dispersed with sonication. The thermal conductivity of PI composite films reached 11.19 Wm−1 K−1 at the low content of 1 wt% GF and 10 wt% AlN, which is ascribed to the construction of synergistically enhanced heat transfer pathways by the combination of the hybrid fillers. The PI composite films with hybrid fillers also showed lower electrical conductivity than that of the PI composite films with single GF filler. This study provides an effective method for preparation of high‐performance thermal management materials.
Fetal MRI for dummies: what the fetal medicine specialist should know about acquisitions and sequences
Authors: Aertsen Michael , Diogo Mariana C. , Dymarkowski Steven , Deprest Jan , Prayer Daniela 
Published: October 2019

AbstractFetal MRI is an increasingly used tool in the field of prenatal diagnosis. While US remains the first line screening tool, as an adjuvant imaging tool, MRI has been proven to increase diagnostic accuracy and change patient counseling. Further, there are instances when US may not be sufficient for diagnosis. As a multidisciplinary field, it is important that every person involved in the referral, diagnosis, counseling and treatment of the patients is familiar with the basic principles, indications and findings of fetal MRI. The purpose of the current paper is to equip radiologists and non‐radiologists with basic MRI principles and essential topics in patient preparation and provide illustrative examples of when fetal MRI may be used. This aims to aid the referring clinician in better selecting and improve patient counseling prior to arrival in the radiology department and, ultimately, patient care.
Synthesis of π‐conjugated polymer containing both thiophene and phosphole sulfide in the main chain by simultaneous post‐element transformation of organotitanium polymer
Authors: Matsumura Yoshimasa , Nishiyama Hiroki , Inagi Shinsuke , Tomita Ikuyoshi 
Published: October 2019

ABSTRACTThe synthesis and unique optoelectronic features of a π‐conjugated polymer containing both thiophene and 1‐phenylphosphole sulfide units (multiple heteroles) in the main chain by the post‐element transformation of a regioregular organometallic polymer possessing titanacyclopentadiene‐2,5‐diyl unit are described. The π‐conjugated polymer containing multiple heteroles was obtained in 73% yield by the simultaneous reaction of the organotitanium polymer with sulfur monochloride and dichlorophenylphosphine (0.6 equiv each), whose number‐average molecular weight (Mn) and the molecular‐weight distribution (Mw/Mn) were estimated to be 11,000 and 3.4, respectively, by the size exclusion chromatography (SEC). The π‐conjugated polymer thus obtained was found to have the high HOMO and the low LUMO energy levels due to the electron‐rich thiophene and electron‐deficient phosphole sulfide units, respectively, as supported by its cyclic voltammetry (CV) analysis. Compared to a mixture of a polymer containing sole thiophene‐unit and that containing sole phosphole sulfide units, the π‐conjugated polymer‐containing multiple heteroles proved to exhibit interesting optical properties. For example, a specific emission peak was observed at 608 nm in the photoluminescence spectrum, which was not observed in the case of the thiophene‐containing polymer, the phosphole‐containing polymer, and their mixture. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2519–2525