bluuebunny/crossref_metadata_2025_split huggingface dataset:
A high precision shooting and bouncing rays method without mesh for scattering calculation of complex target
Authors: Li Jianzhou , Li Shuang 
Published: April 2019

AbstractTo extend the application of shooting and bouncing rays (SBR) method in the penetration structure and further improve the calculation accuracy, an improved mesh free SBR method that completely implements ray‐tracing and electromagnetic computing in 3‐D geometrical modeling software is proposed. The basic idea is to combine the non‐uniform rational b‐splines (NURBS) surface modeling function and open application programming interface (Open API) to implement the process of mesh free ray tracing, which greatly improve calculation accuracy and efficiency of SBR. Based on this, the improved SBR method can yield a superior performance for scattering analysis of complex targets, especially at the problem where reflected and transmitted waves exist simultaneously in a target. The numerical results demonstrate that the improved SBR is highly effective in computing scattering fields of complex targets.
Simultaneous determination of nine trace concentration angiotensin peptides in human serum using ultra high performance liquid chromatography with tandem mass spectrometry with sephadex LH‐20 gel solid‐phase extraction
Authors: Shen Yue , Liu Mingyang , Xu Mingyue , Xu Zhanling , Na Yue , Zhang Ning , Geng Fang 
Published: April 2019

AbstractThe renin–angiotensin system is a highly complex enzymatic system consisting of multiple peptide hormones, enzymes, and receptors. Here, an assay to simultaneously quantify eight angiotensin peptides and bradykinin in human serum was developed and validated, using ultra high performance liquid chromatography coupled with tandem mass spectrometry. A pre‐concentration method of Sephadex LH‐20 gel solid‐phase extraction was first applied for analysis of angiotensin peptides from serum sample. The triple quadrupole mass spectrometer was operated in the positive ion mode and multiple reaction monitoring was used for drug quantification. The analytical time was within 5 min, much raising the analysis efficiency. Limits of detection ranged from 0.9 to 1.3 pg/mL, and displayed the same level of sensitivity compared with radioimmunoassay. The method was successfully applied to 22 healthy human serum samples, giving the concentrations of angiotensin I, angiotensin II, angiotensin III, angiotensin IV, angiotensin 1–9, angiotensin 1–7, angiotensin 1–5, Asn1,Val5‐Angiotensin II, and bradykinin for reference. This novel metabolic profile study of vasoactive peptides based on gel solid‐phase extraction concentration provided not only an accurate quantitative assay of the serum concentrations, but also a promising methodology for evaluating the diagnostic values of the various peptides.
Safety and reliability of a handheld stimulator for neural monitoring during thyroid surgery
Authors: Lawson Bradley R. , Kamani Dipti , Shama Mohamed , Kyriazidis Natalia , Randolph Gregory W. 
Published: April 2019

ObjectiveThe Checkpoint nerve stimulator (Checkpoint Surgical, Cleveland, OH) is a U.S. Food and Drug Administration‐approved device for neural localization and monitoring during surgery. Its safety, efficacy, and reliability for neural monitoring during thyroid and parathyroid surgery have not been compared to more standard formats of neural monitoring.Study DesignRetrospective review.MethodsVagal, recurrent, and superior laryngeal nerve monitoring were performed using both the Checkpoint stimulator and Medtronic NIM 3.0 laryngeal electromyography endotracheal tube (Medtronic, Jacksonville, FL) during thyroid and parathyroid surgery. A total of 21 operated sides in 15 patients were included for analysis. Latency and amplitude data for the Checkpoint stimulator were recorded using the NIM monitor and compared to normative endotracheal tube surface electrode data.ResultsMean amplitude using the Checkpoint stimulator was 574.6 microvolts (μV), 1060.6 μV, and 182.8 μV for the vagus, recurrent laryngeal, and superior laryngeal nerves, respectively. Mean amplitude using standard laryngeal electromyography was 709 μV, 1077.0 μV, and 183.7 μV for the same nerves. Mean latency was significantly shorter with stimulation of the recurrent laryngeal nerve compared to the vagus nerve with both stimulators (P < 0.001). No neural injuries occurred during the study.ConclusionThe Checkpoint stimulator is a safe and reliable alternative to traditional laryngeal electromyography providing equivalent induced electromyography of the vocalis for neural monitoring during thyroid and parathyroid surgery.Level of Evidence4 Laryngoscope, 130:561–565, 2020
Response of boreal lakes to changing wind strength: Coherent physical changes across two large lakes but varying effects on primary producers over the 20th century
Authors: Strock Kristin E. , Saros Jasmine E. , McGowan Suzanne , Edlund Mark B. , Engstrom Daniel R. 
Published: April 2019

AbstractNear‐surface wind speeds have changed over recent decades, raising questions about the extent to which these changes are altering the vertical thermal structure of lakes and affecting lake food webs. Neo‐ and paleolimnological techniques were used to assess wind‐driven changes in lake thermal habitat and resulting effects on primary producers in two lakes in Isle Royale National Park, an island archipelago located in Lake Superior, where wind speed has increased in recent decades. Responses in Siskiwit Lake, a large (16 km2 surface area), deep (Zmax = 49 m), oligotrophic lake, were compared to those of Lake Desor, a moderately large (4.3 km2) but shallower (Zmax = 13 m), mesotrophic lake. High‐frequency sensor data suggested that changes in wind speed affected epilimnion thickness in both lakes synchronously (ρ = 0.7, p < 0.001). Diatom‐inferred mixing depths suggested a coherent shift in both lakes to deeper mixing (an increase of 3 and 6 m) since 1920 (ρ = 0.8), which was correlated with an increase in regional wind speed during the 20th century at the decadal‐scale in Lake Desor and Siskiwit Lake (ρ = 0.6 and 0.4, respectively). In Lake Desor, algal biomass declined as mixing deepened from 1920 to 1980, and then cyanobacteria and cryptophyte pigments increased from 1980 to present, a period of inferred stable and deep mixing. Algal pigment concentrations in Siskiwit Lake were unchanged as mixing depth deepened. Although changes in wind speed altered lake physical structure similarly, the ecological consequences of these changes differed between lakes and were most likely influenced by lake‐specific variability in nutrient and light availability.
Hydrophilicity Tunable Hyperbranched Polymers by Visible Light Induced Self‐Condensing Vinyl Polymerization
Authors: Bener Semira , Aydogan Cansu , Yagci Yusuf 
Published: April 2019

AbstractA facile and efficient route for synthesizing hydrophilicity tunable hyperbranched polymers is described. The method is based on the visible light induced self‐condensing vinyl copolymerization of tert‐butyl acrylate (tBA) and 2‐(2‐bromoisobutryloxy)ethyl methacrylate (BIBEM) as monomer and inimer, respectively, in the presence of dimanganese decacarbonyl (Mn2(CO)10). Subsequently, the hydrophlicity of the resulting hydrophobic hyperbranched polymers is tuned by hydrolysis of the tert‐butyl ester moieties of the copolymer. The effect of inimer concentration and irradiation time on the branching density and hydrophilicity is evaluated. The precursor and hydrolyzed hyperbranched polymers are characterized by 1H NMR, GPC, FT‐IR, and contact angle measurements.
Glass Transition Phenomenon for Conjugated Polymers
Authors: Qian Zhiyuan , Cao Zhiqiang , Galuska Luke , Zhang Song , Xu Jie , Gu Xiaodan 
Published: April 2019

AbstractConjugated polymers are emerging as promising building blocks for a broad range of modern applications including skin‐like electronics, wearable optoelectronics, and sensory technologies. In the past three decades, the optical and electronic properties of conjugated polymers have been extensively studied, while their thermomechanical properties, especially the glass transition phenomenon which fundamentally represents the polymer chain dynamics, have received much less attention. Currently, there is a lack of design rules that underpin the glass transition temperature of these semirigid conjugated polymers, putting a constraint on the rational polymer design for flexible stretchable devices and stable polymer glass that is needed for the devices’ long‐term morphology stability. In this review article, the glass transition phenomenon for polymers, glass transition theories, and characterization techniques are first discussed. Then previous studies on the glass transition phenomenon of conjugated polymers are reviewed and a few empirical design rules are proposed to fine‐tune the glass transition temperature for conjugated polymers. The review paper is finished with perspectives on future directions on studying the glass transition phenomena of conjugated polymers. The goal of this perspective is to draw attention to challenges and opportunities of controlling, predicting, and designing polymeric semiconductors, specifically to accommodate their end use.
Melting, Solidification, and Crystallization of a Thermoplastic Polyurethane as a Function of Hard Segment Content
Authors: Stribeck Almut , Eling Berend , Pöselt Elmar , Malfois Marc , Schander Edgar 
Published: April 2019

AbstractThermoplastic polyurethanes (TPU) with varying hard segment contents (HSC) are monitored during melting and solidifying (, Tmax = 220 ° C) by small‐angle and wide‐angle X‐ray scattering (WAXS and SAXS). Hard segments: MDI/BD. Soft segments: PTHF1000. The neat materials are injection‐molded, having small amorphous hard domains (chord length ). Results indicate complexity of morphology changes. For example, crystals are predominantly produced in freshly segregated, sufficiently large hard domains, while the temperature decreases slowly enough. After the thermal treatment, only the materials with HSC >∼ 35% show sharp Bragg peaks and larger hard domains (). When heated, small domains melt, but crystallization in the remaining large domains is not detected. Upon cooling, large agglomerates segregate first, which crystallize immediately. Segregation starts for HSC = 42% at 160 °C and for HSC = 75% at 210 °C. When HSC ≤ 30%, the morphologies before and after are similar, but afterward, many hard blocks are dissolved in the soft phase at the expense of the hard domain fraction. In heating and cooling the melts, multiple homogenization and segregation processes are observed, which are explained by the agglomeration of hard blocks of different lengths in the colloidal fluid.
The Influence of Al2O3 and TiO2 Additives on the Electrical Resistivity of Epoxy Resin‐Based Composites at Low Temperature
Authors: Eker Yasin Ramazan , Özcan Muciz , Özkan Ali Osman , Kırkıcı Hülya 
Published: April 2019

AbstractElectrical insulation is a major security problem in aerospace applications where temperature can reach relatively low values. Epoxy resins are well known as easily formable dielectric materials and can be used to prepare complex insulator parts. In this study, the electrical performance of bisphenol A/epichlorohydrin epoxy resin matrix‐based nanocomposites containing 1, 3, or 6 wt% titanium oxide (TiO2) or aluminium oxide (Al2O3) nanofillers are investigated. Composites are characterized with thermogravimetric analysis, scanning electron microscopy‐coupled electron dispersive spectroscopy, and confocal Raman spectroscopy. Furthermore, the role of additives and their ratio on the resistivity performance of the composites are evaluated from 77 to 500 K by applying a direct current voltage from 1 to 20 V. It is observed that the electrical properties of the matrix are directly influencing the insulation performance of the nanocomposite. For example, the abrupt decrease at 370 K of the positive temperature coefficient of the resin for all nanocomposites. It is found that the most resistive composite contains 3 wt% TiO2 nanoparticles with a value above 3.7.1010 Ω from 77 to 370 K at 20 V. As a result, this work gives information on to the choice of appropriate insulator materials in extreme working conditions.
Anhydride Cured Bio‐Based Epoxy Resin: Effect of Moisture on Thermal and Mechanical Properties
Authors: Anusic Andrea , Resch‐Fauster Katharina , Mahendran Arunjunai Raj , Wuzella Günter 
Published: April 2019

AbstractThis paper describes the development of a novel thermoset based on epoxidized hemp seed oil. The optimization of the hardener (anhydride) and crosslinking accelerator (2‐ethylimidazol) concentration as well as the curing parameters are discussed in detail. The optimized material exhibits a bio‐based carbon portion of 57.5 wt% and represents an innovative and sustainable substitute for fully petrochemical‐based resins in terms of thermal and mechanical performance characteristics. However, also a major challenge with regard to practical applications of (bio‐based) thermosets with anhydride curing agent thermosets is identified and addressed: the sensitivity to moisture absorption both during curing and in the fully cured state.
The Effect of Epoxidation on Strain‐Induced Crystallization of Epoxidized Natural Rubber
Authors: Zhang Xi , Niu Kaijing , Song Weixiao , Yan Shouke , Zhao Xiuying , Lu Yonglai , Zhang Liqun 
Published: April 2019

AbstractThe effect of epoxidation on strain‐induced crystallization (SIC) of epoxidized natural rubber (ENR) and mechanism are studied with synchrotron radiation wide‐angle X‐ray diffraction (SR‐WAXD) and polarized infrared spectroscopy (P‐IR). WAXD results reveal that appropriate epoxidation, for example, ENR‐25 epoxidized with ≈25% isoprene units, can unexpectedly enhance the SIC of natural rubber (NR), resulting in the improvement of tear resistance. On the other hand, exorbitant epoxidation, for example, ENR‐40 epoxidized with ≈40% isoprene units, depresses the SIC and weakens the mechanical properties of NR remarkably. P‐IR studies reveal that epoxidation can promote the orientation of chain segments along the stretching direction, which plays a determining role on SIC of NR. Accordingly, hierarchical multiscale schematic models are proposed. This insight into epoxidation on SIC of ENR strongly suggests that ENR with appropriate epoxidation degree is a promising candidate material for the fabrication of high‐performance engineering rubber products.
First Observations of Long-Distance Migration in a Large Skate Species, the Winter Skate: Implications for Population Connectivity, Ecosystem Dynamics, and Management
Authors: Frisk Michael G. , Shipley Oliver N. , Martinez Christopher M. , McKown Kim A. , Zacharias Joshua P. , Dunton Keith J. 
Published: April 2019

Abstract
The overexploitation and decline of groundfish populations throughout the 1980s and 1990s resulted in a regime shift on Georges Bank and southern New England, which was characterized by subsequent exponential increases in the observed biomass of Winter Skate Leucoraja ocellata in the region. Recent work suggested that the rate of the Winter Skate biomass increase cannot be fully explained by internal population dynamics of a population without immigration from other regions and/or populations and that adult-mediated population connectivity (AMPC) with neighboring regions is required to fully explain biomass trends. Despite this, no evidence of long-distance dispersal has been observed for Winter Skate, with individuals assumed to display high endemicity to specific regions of the continental shelf. Annual movements of 58 Winter Skate captured off coastal New York were examined using passive acoustic telemetry, revealing seasonal long-distance dispersal capabilities exceeding 1,000 km. In total, 88,783 unique acoustic detections were observed. Telemetered individuals had an average time at liberty of 199.73 d and collectively traveled 17,576.9 km. Individuals tended to migrate south during summer/fall and north during winter/spring. Movement rates of individuals averaged 9.88 km/d (95% confidence interval = 9.25–10.92 km/d) but ranged from 0.13 to 41.38 km/d. An additional 51 recaptured Winter Skate from a total of 3,416 marked with Floy tags suggested greater offshore movement than was observed in acoustically tagged individuals. Our results illustrate that the Winter Skate is a highly mobile species that moves extensively throughout its large geographic range, consistent with its observed ability to rapidly invade neighboring habitat via AMPC. This study has important implications for our understanding of the role of Winter Skate in northwest Atlantic communities and for management strategies therein.
Age, Growth, Natural Mortality, and Reproductive Seasonality of Knobbed Porgy from Southeastern United States Waters
Authors: Burton Michael L. , Potts Jennifer C. , Poholek Ariel J. , Ostrowski Andy , Page Jordan 
Published: April 2019

Abstract
The Knobbed Porgy Calamus nodosus, an important secondary species in reef fish catches of the southeastern United States, was recently the subject of a fishery closure due to the porgy complex quota being exceeded. Knobbed Porgy (n = 448) were aged using sectioned sagittal otoliths. Opaque zones on otolith sections were annular, forming in March–July (peaking in May). Knobbed Porgy ranged from 1 to 21 years, and the largest fish measured 507 mm TL. Body size relationships relating TL, FL, and total body weight (W) for Knobbed Porgy were TL = 1.07·FL + 22.93 (n = 3,173; r2 = 0.97), FL = 0.91·TL − 12.54 (n = 3,173; r2 = 0.97), W = (1.38 × 10−5)TL3.03 (n = 12,732; r2 = 0.92), and W = (7.99 × 10−5)FL2.79 (n = 3,199; r2 = 0.90). Mean length at age was significantly different between Knobbed Porgy collected in North Carolina through southeast Florida (northern region) and those collected in the Florida Keys (southern region). The von Bertalanffy growth equations for Knobbed Porgy were Lt = 412[1 − e−0.20(t + 1.97)] (n = 448) for all regions combined, Lt = 403[1 − e−0.38(t + 0.0001)] (n = 117) for northern region fish, and Lt = 326[1 − e−0.42(t + 1.61)] (n = 331) for southern region fish. Age-varying estimates of natural mortality were 0.36–0.79 year−1 (ages 2–21) for the northern region and 0.42–0.67 year−1 (ages 1–12) for fish from the Florida Keys. Hydrated oocytes were present during February–April in macroscopically staged ovaries (n = 148) for fish from the Florida Keys, and gonadosomatic index data indicated that the month of peak spawning in females was April. The updated life history information should be useful to fishery managers in formulating effective management strategies.
Assessing test–retest reliability of phase contrast MRI for measuring cerebrospinal fluid and cerebral blood flow dynamics
Authors: Sakhare Ashwin R. , Barisano Giuseppe , Pa Judy 
Published: April 2019

PurposePathological states occur when cerebrospinal fluid (CSF) and cerebral blood flow (CBF) dynamics become dysregulated in the brain. Phase‐contrast MRI (PC‐MRI) is a noninvasive imaging technique that enables quantitative measurements of CSF and CBF flow. While studies have validated PC‐MRI as an imaging technique for flow, few studies have evaluated its reliability for CSF and CBF flow parameters commonly associated with neurological disease. The purpose of this study was to evaluate test–retest reliability at the cerebral aqueduct (CA) and C2‐C3 area using PC‐MRI to assess the feasibility of investigating CSF and CBF flow dynamics.MethodsThis study was performed on 27 cognitively normal young adults (ages 20‐35 years). Flow data was acquired on a 3T Siemens Prisma using a 2D cine‐PC pulse sequence. Three consecutive flow measurements were acquired at the CA and C2‐C3 area. Intraclass correlation coefficient (ICC) and coefficient of variance (CV) were used to evaluate intrarater, inter‐rater, and test–retest reliability.ResultsAmong the 26 flow parameters analyzed, 22 had excellent reliability (ICC > 0.80), including measurements of CSF stroke volume, flush peak, and fill peak, and 4 parameters had good reliability (ICC 0.60‐0.79). 16 flow parameters had a mean CV ≤ 10%, 7 had a CV ≤ 15%, and 3 had a CV ≤ 30%. All CSF and CBF flow measurements had excellent inter‐rater and intrarater reliability (ICC > 0.80).ConclusionThis study shows that CSF and CBF flow can be reliably measured at the CA and C2‐C3 area using PC‐MRI, making it a promising tool for studying flow dynamics in the central nervous system.
Development of a fast‐scan EPR imaging system for highly accelerated free radical imaging
Authors: Samouilov Alexandre , Ahmad Rizwan , Boslett James , Liu Xiaoping , Petryakov Sergey , Zweier Jay L. 
Published: April 2019

PurposeIn continuous wave EPR imaging, the acquisition of high‐quality images was previously limited by the requisite long acquisition times of each image projection that was typically greater than 1 second. To accelerate the process of image acquisition facilitating greater numbers of projections and higher image resolution, instrumentation was developed to greatly accelerate the magnetic field scan that is used to obtain each EPR image projection.MethodsA low‐inductance solenoidal coil for field scanning was used along with a spherical solenoid air core magnet, and scans were driven by triangular symmetric waves, allowing forward and reverse spectrum acquisition as rapid as 3.8 ms. The uniform distribution of projections was used to optimize the contribution of projections for 3D image reconstruction.ResultsUsing this fast‐scan EPR system, high‐quality EPR images of phantoms and perfused rat hearts were performed using trityl or nanoparticulate LiNcBuO (lithium octa‐n‐butoxy‐substituted naphthalocyanine) probes with fast‐scan EPR imaging at L‐band, achieving spatial resolutions of up to 250 micrometers in 1 minute.ConclusionFast‐scan EPR imaging can greatly facilitate the efficient and precise mapping of the spatial distribution of free radical and other paramagnetic probes in living systems.
Quantitative1HNMR spectroscopy for the determination of oxyresveratrol inArtocarpus lacuchaheartwood
Authors: Duangdee Nongnaphat , Chamboonchu Natawadee , Kongkiatpaiboon Sumet , Prateeptongkum Saisuree 
Published: April 2019

AbstractIntroductionQuantitative nuclear magnetic resonance (qNMR) spectroscopy is an analytical method based on the principles of NMR spectroscopy. The main advantages of this method are its simplicity, time efficiency, high accuracy and reproducibility, and it is a non‐destructive technique.ObjectiveTo evaluate and standardise the quality ofArtocarpus lacuchaheartwood. A method for quantifying its oxyresveratrol content using qNMR was developed.MethodologyProton (1H)NMR (400 MHz) spectroscopy was used to analyse the methanol‐d4solution of a given amount of crude extract ofA. lacuchaheartwood using ethylp‐methoxycinnamate (EPMC) as an internal standard. The qNMR methodology was validated in terms of its linearity and range, limit of quantification (LOQ), stability, precision, and accuracy for the determination of the oxyresveratrol content.ResultsThe qNMR method was validated in terms of its linearity, range, LOQ, accuracy, precision, and stability. The quantitative determination of the oxyresveratrol content in the methanolic crude extract ofA. lacuchawas found to be 17% based on1HNMR analysis, which proved to be a reliable method as the results were comparable to those obtained by high‐performance liquid chromatography (HPLC) analysis.ConclusionsThis study validated qNMR spectroscopy as a reliable analytical procedure to determine oxyresveratrol inA. lacuchaheartwood. Therefore, this qNMR method can serve as an alternative to the classical HPLC methods for evaluating and standardising the quality ofA. lacuchaheartwood.