bluuebunny/crossref_metadata_2025_split huggingface dataset:
Compact CPW‐fed ultra‐wideband printed antennas with controllable notch characteristics
Authors: Li Yafeng , Li En , Gao Chong , Yang Tao 
Published: October 2018

AbstractIn this paper, a series of compact and miniaturized UWB‐printed antennas with a controllable notch function are proposed. The CPW structure is adopted to feed the proposed antenna, where the overall dimension is as compact as 15 mm × 15 mm × 0.5 mm. From 2.8GHz to 12GHz, the antennas proposed have a superior performance with approximate 2:1 VSWR, except the rejection frequency band. In addition, the main feature of the proposed antennas are their controllable notch frequency, notch amplitude, and notch orders, which are determined by the size of the circular U‐shaped slit, the position of the connecting line, and the number of slits, respectively. Moreover, the measured results are in reasonably good with the simulated results.
Wavelength‐dependent transient gain saturation in an erbium‐doped fiber amplifier under different pump conditions
Authors: Kuroda Keiji , Tanaka Kei , Yoshikuni Yuzo 
Published: October 2018

AbstractWe report measurements of wavelength‐dependent gain saturation in an erbium‐doped fiber amplifier over a wavelength range of 30 nm under four different pump conditions. The wavelength and the pump dependences were simultaneously analyzed using a theoretical model with the McCumber relation. Our results could be reproduced using a single theoretical model.
Objective acceleration for unconstrained optimization
Authors: Riseth Asbjørn Nilsen 
Published: October 2018

SummaryAcceleration schemes can dramatically improve existing optimization procedures. In most of the work on these schemes, such as nonlinear generalized minimal residual (N‐GMRES), acceleration is based on minimizing the ℓ2 norm of some target on subspaces of
. There are many numerical examples that show how accelerating general‐purpose and domain‐specific optimizers with N‐GMRES results in large improvements. We propose a natural modification to N‐GMRES, which significantly improves the performance in a testing environment originally used to advocate N‐GMRES. Our proposed approach, which we refer to as O‐ACCEL (objective acceleration), is novel in that it minimizes an approximation to the objective function on subspaces of
. We prove that O‐ACCEL reduces to the full orthogonalization method for linear systems when the objective is quadratic, which differentiates our proposed approach from existing acceleration methods. Comparisons with the limited‐memory Broyden–Fletcher–Goldfarb–Shanno and nonlinear conjugate gradient methods indicate the competitiveness of O‐ACCEL. As it can be combined with domain‐specific optimizers, it may also be beneficial in areas where limited‐memory Broyden–Fletcher–Goldfarb–Shanno and nonlinear conjugate gradient methods are not suitable.
A shape optimization approach for simulating contact of elastic membranes with rigid obstacles
Authors: Sharma Akriti , Rangarajan Ramsharan 
Published: October 2018

SummaryThe obstacle problem consists in computing equilibrium shapes of elastic membranes in contact with rigid obstacles. In addition to the displacement u of the membrane, the interface Γ on the membrane demarcating the region in contact with the obstacle is also an unknown and plays the role of a free boundary. Numerical methods that simulate obstacle problems as variational inequalities share the unifying feature of first computing membrane displacements and then deducing the location of the free boundary a posteriori. We present a shape optimization‐based approach here that inverts this paradigm by considering the free boundary to be the primary unknown and compute it as the minimizer of a certain shape functional using a gradient descent algorithm. In a nutshell, we compute Γ then u, and not u then Γ. Our approach proffers clear algorithmic advantages. Unilateral contact constraints on displacements, which render traditional approaches into expensive quadratic programs, appear only as Dirichlet boundary conditions along the free boundary. Displacements of the membrane need to be approximated only over the noncoincidence set, thereby rendering smaller discrete problems to be resolved. The issue of suboptimal convergence of finite element solutions stemming from the reduced regularity of displacements across the free boundary is naturally circumvented. Most importantly perhaps, our numerical experiments reveal that the free boundary can be approximated to within distances that are two orders of magnitude smaller than the mesh size used for spatial discretization. The success of the proposed algorithm relies on a confluence of factors‐ choosing a suitable shape functional, representing free boundary iterates with smooth implicit functions, an ansatz for the velocity of the free boundary that helps realize a gradient descent scheme and triangulating evolving domains with universal meshes. We discuss these aspects in detail and present numerous examples examining the performance of the algorithm.
Characterisation and screening of antimicrobial essential oil components against clinically important antibiotic‐resistant bacteria using thin layer chromatography‐direct bioautography hyphenated with GC‐MS, LC‐MS and NMR
Authors: Owen Lucy , White Alex W. , Laird Katie 
Published: October 2018

AbstractIntroductionThe antimicrobial activity of many essential oils (EOs) is well established, indicating that EOs may be a source of compounds for antimicrobial drug development. Thin layer chromatography‐direct bioautography (TLC‐DB) can quickly identify antimicrobial components in complex mixtures and can be applied to the screening of EOs for lead compounds.ObjectivesThis study aimed to identify antimicrobial components of oregano, rosewood and cumin EOs against antibiotic‐sensitive and ‐resistant bacteria using TLC‐DB and a multi‐faceted approach of GC‐MS, LC‐MS and NMR techniques to characterise bioactive compounds. The study also aimed to quantify the antimicrobial activity of bioactive compounds in order to evaluate their potential for the development of therapies against antibiotic‐resistant bacteria.Materials and MethodsEOs were eluted on TLC plates and sprayed with a suspension of Staphylococcus aureus, Enterococcus faecium, Escherichia coli or Pseudomonas aeruginosa (antibiotic‐sensitive and ‐resistant isolates). Zones of inhibition, visualised with iodonitrotetrazolium chloride, were subject to GC‐MS, LC‐MS and NMR to characterise the bioactive compounds.ResultsSeven compounds were identified from the three EOs using GC‐MS, while LC‐MS and NMR failed to detect the presence of any further non‐volatile or heat labile compounds. Carvacrol was most antimicrobial compound identified, with minimum inhibitory concentrations ranging 0.99–31.62 mM.ConclusionThe identified antimicrobial compounds present in oregano, rosewood and cumin EOs including carvacrol may be candidates for the development of novel antimicrobial therapies against antibiotic‐resistant bacteria.
Establishment of normative values for the fetal posterior fossa by magnetic resonance imaging
Authors: Chapman Teresa , Menashe Sarah J. , Zare Megan , Alessio Adam M. , Ishak Gisele E. 
Published: October 2018

AbstractObjectiveSuspected Dandy‐Walker continuum anomalies constitute a significant percentage of prenatal cases evaluated by magnetic resonance imaging (MRI). To unify the description of posterior fossa malformations, we sought to establish objective measurements for the posterior fossa in normal fetuses between 18 and 37 weeks gestation.MethodsT2‐weighted images of normal fetal brains in sagittal projection were obtained from fetal magnetic resonance (MR) studies of normal brains performed from 2009 to 2017.121 fetal brains were included in the analysis. Three radiologists reviewed images and recorded the following for each case: superior posterior fossa angle (SPFA), posterior fossa perimeter, and tegmento‐vermian angle (TVA).ResultsFor each feature, the mean of the measurements, the percentage of absolute difference of the reader measurement compared with mean measurement, and the interclass correlation (ICC) were calculated. Values are reported as mean ± standard deviation. Perimeter increases linearly with age, whereas the SPFA and the TVA are independent of gestational age. For all included cases, the SPFA averaged 100.9° ± 8° and the TVA averaged 2.5° ± 2.3°.ConclusionThe superior posterior fossa angle, a novel measurement, and the posterior fossa perimeter can be used for establishing the expected size of the posterior fossa in second‐ and third‐trimester fetuses by MRI.
Switchable phase transition behavior of thermoresponsive substrates for cell sheet engineering
Authors: Mokhtarinia Kiana , Nourbakhsh Mohammad Sadegh , Masaeli Elahe , Entezam Mehdi , Karamali Fereshteh , Nasr‐Esfahani Mohammad Hossein 
Published: October 2018

ABSTRACTRecently, there are significant interests in the development of biomaterials with nonlinear response to an external stimulus. Thermoresponsive polymers as a well‐known class of stimuli‐responsive materials represent reversible hydrophilicity/hydrophobicity characteristics around a critical temperature. This switchable behavior applies for nondestructive cellular detachment from cultivation substrates. In this study, poly (N‐isopropylacrylamide) (PNIPAAm)‐grafted dishes were made up to harvest retinal pigmented epithelial (RPE) and periodontal ligament cell (PDLC) sheets. Wettability assessments verified that all functionalized surfaces were inverted from hydrophilic to hydrophobic state when the temperature rises from lower critical solution temperature (LCST) at 37 °C. Other physicochemical characteristics such as chemical composition, grafting thickness, and surface topography were investigated through attenuated total reflection Fourier transform infrared spectroscopy (ATR‐FTIR) and atomic force microscopy (AFM). ATR‐FTIR results showed typical peaks of amide group corresponding to successful PNIPAAm polymerization. AFM microscopy results also proved creating a rough PNIPAAm layer with thickness of 29.2 nm after grafting process in the mixture of methanol and water. Cell culture experiments showed an irreversible cellular attachment/detachment from modified surfaces upon temperature changes. These results introduced thermoresponsive TCPS to noninvasively harvest RPE and PDLCs sheets especially for application in scaffold‐free tissue engineering decorations. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018, 56, 1567–1576
Ginsenoside Rg3 and Rh2 protect trimethyltin‐induced neurotoxicity via prevention on neuronal apoptosis and neuroinflammation
Authors: Hou Jingang , Xue Jianjie , Wang Zi , Li Wei 
Published: October 2018

The acute exposure of trimethyltin (TMT) develops clinical syndrome characterized by amnesia, aggressive behavior, and complex seizures. This neurotoxicant selectively induces hippocampal neuronal injury and glial activation accompanied with resultant neuroinflammation. Here we report two candidates ginsenosides Rg3 and Rh2 as neuroprotection agents using a mouse model of TMT intoxication via a single injection (2 mg/kg) and primary neuronal culture systems. Four‐week administration of Rg3 or Rh2 significantly reduced TMT‐induced seizures and behavioral changes. Rg3 and Rh2 significantly attenuated the oxidative stress evidenced by improvement on antioxidant enzymes and neuronal loss and astrocytic activation in mouse brain. In primary cultures, TMT induced significant neuronal death after 24‐h intoxication and vigorous secretion of inflammatory cytokines (IL‐1α/β, IL‐6, TNF‐α, and MCP‐1) in astrocytes. Pretreatment with Rg3 or Rh2 not only reduced cell death but efficiently suppressed above mentioned inflammatory cytokines confirmed by antibody array test. The underlying protective mechanism by Rg3 and Rh2 was delineated through selective upregulation of PI3K/Akt and suppression of ERK activation. Intriguingly, Rg3 and Rh2 protected oligodendrocyte progenitor cells (O‐2A) from TMT intoxication via promoting type 2 astrocytic differentiation without further inflammatory activation. Collectively, Rg3 and Rh2 interventions aimed at reducing oxidative stress and neuroinflammation neurotoxicity therefore are of therapeutic benefit in TMT‐induced neurodegeneration.
Stable isotope ratios of carbon, nitrogen and selenium concentration in the scalp hair of Crohn's disease patients who ingested the elemental diet Elental®
Authors: Ogasawara Hideki , Hayasaka Moriaki , Maemoto Atsuo , Furukawa Shigeru , Ito Takahiro , Kimura Osamu , Endo Tetsuya 
Published: October 2018

RationaleElental® is an elemental diet widely used as a nutritional supplement for Crohn's disease (CD) patients in Japan. Elental® contains amino acids as nitrogen sources and does not contain selenium (Se), and the δ13C and δ15N values of Elental® are markedly higher and lower, respectively, than those of a normal diet.MethodsWe compared the δ13C and δ15N values and Se concentration in the scalp hair of CD patients with those of control subjects who ate a regular diet, and estimated the amount of Elental® ingested as a supplement. The δ13C and δ15N values and the Se concentrations were quantified using isotope ratio mass spectrometry (IRMS) and inductively coupled plasma mass spectrometry (ICP‐MS), respectively.ResultsAn increase in Elental® ingestion increased the δ13C value in the hair of CD patients (p <0.05), while it reduced the δ15N value (p <0.05) and tended to reduce the Se concentration in female patients.ConclusionsThe amount of Elental® ingested could be estimated by the δ13C and δ15N values in the hair of CD patients. Furthermore, the Se deficiency in female patients may be predicted from the δ13C and δ15N values.
Gas‐phase rearrangement reaction of Schiff‐base‐modified peptide ions
Authors: Wang Nan , Pilo Alice L. , Zhao Feifei , Bu Jiexun , McLuckey Scott A. 
Published: October 2018

RationaleSchiff base modification of peptides has been shown to facilitate their primary structural characterization via tandem mass spectrometry. However, we have discovered a novel rearrangement reaction via ion trap collisional activation involving the imine of the Schiff base and one of several functional groups, particularly the side chains of the basic residues lysine, arginine, and histidine, in the peptide.MethodsGas‐phase ion/ion reactions involving an aldehyde‐containing reagent were used to generate Schiff‐base‐modified model peptides in a hybrid triple quadrupole/linear ion trap tandem mass spectrometer. Subsequent ion trap collisional activation was used to study the rearrangement reaction.ResultsSchiff‐base‐modified peptide ions were found to undergo a rearrangement reaction that was observed to be either a major or minor contributor to the product ion spectrum, depending upon a variety of factors that include, for example, ion polarity, identity of the nucleophile in the peptide (e.g., side chains of lysine, histidine, and arginine), and the position of the nucleophile relative to the imine.ConclusionsRelatively low‐energy rearrangement reactions can occur in Schiff‐base‐modified peptide ions that involve the imine of the Schiff base and a nucleophile present in the polypeptide. While this rearrangement process does not appear to compromise the structural information that can be generated via collisional activation of Schiff‐base‐modified peptide ions, it can siphon away signal from the structurally diagnostic processes in some instances.
Water hyacinth (Eichhornia crassipes) invasion and establishment in a temperate river system
Authors: VonBank Jay A. , Casper Andrew F. , Pendleton Jennifer E. , Hagy Heath M. 
Published: October 2018

AbstractWater hyacinth (Eichhornia crassipes) is an invasive aquatic macrophyte that is prolific throughout many regions worldwide, but it has recently been detected in several areas of the Midwest United States, outside of its historical range. We assessed the occurrence of water hyacinth in the upper Illinois River to understand the current distribution and potential establishment pathways within a large river system in a temperate climate. We estimated plant biomass and occurrence of seeds in substrate and the water column at locations where water hyacinth occurred and other areas throughout the study area. Biomass of seeds varied temporally and spatially, but no potential water hyacinth seeds germinated during germination trials and germination rates for unscarified water hyacinth seeds from an established population were extremely low. Interestingly, a high abundance and diversity of seeds were detected below water hyacinth mats indicating that water hyacinth root systems may also act as a barrier to hydrochoric seeds in large river systems. Generally, the occurrence of water hyacinth mats and propagules during our study did not pose any apparent issues for commercial navigation due to low overall occurrence and biomass, late occurrence in the growing season, and nongermination of seeds. However, presence of potential water hyacinth in the seed bank and rapid proliferation late in the growing season could pose issues for recreational navigation in low‐flow areas and suggests increased risk if environmental conditions become more suitable for establishment. Occurrence of water hyacinth in the upper Illinois River likely relies on biomass reintroduction annually by humans, and behavioural modification or legal means may be necessary to reduce future occurrences.
The Unfolding and Resurfacing of Information Systems Knowledge over the Last 25 Years: A Systemic Perspective
Authors: Córdoba‐Pachón José‐Rodrigo , Paucar‐Caceres Alberto 
Published: October 2018

Currently, there are many perspectives aiming to account for what the field of information systems (IS) is or should be. For some, IS is conceived as a reference and stable discipline with dominant or core knowledge to export to other disciplines. To others, IS still requires a more eclectic/fluid perspective to enable IS to be adaptable to emerging challenges and possibilities. In both types of perspectives, there is a need to appreciate fully how IS knowledge has effectively unfolded through time in broader contexts of social sciences. In line with an emerging research orientation to conceive the IS field as both dominant and eclectic, we propose a systemic framework to account for these stages. We identify key IS knowledge concepts/themes emerging from analysing 4100 abstracts from articles in eight IS journals covering European Union/US regions over the last 25 years. Our findings suggest that such knowledge does not accumulate, but rather, some IS key concepts like systems, information and use resurface over time, leading to draw important implications for IS education, research and practice. © 2018 John Wiley & Sons, Ltd.
Stipulating Low Production Cost Solar Cells All Set to Retail…!
Authors: Mrinalini Madoori , Islavath Nanaji , Prasanthkumar Seelam , Giribabu Lingamallu 
Published: October 2018

AbstractToday's solar cells are exceptionally in demand whilst excess exploitation of natural fossil fuels. In this context, the first and second generation solar cells commercially available in market for more than decades however limitations in production cost and large–scale applications insist to generate inexpensive materials for fabrication. Thereby, organic materials based solar cells explored and emerging as third generation solar cells which possess flexibility, low cost and large‐scale applications. For example, organic photovoltaics, dye sensitized solar cells and perovskite (organic‐inorganic) solar cells (PSCs) are considered third generation solar cells wherein PSCs reached the record power conversion efficiency (PCE ∼23 %) and durability assists great advantages for commercialization in near future. Moreover, we reported various global renowned companies involved producing the modules and materials for three generation solar cells, hence, majority of companies considered commercialization of perovskite based solar cells assist low cost photovoltaics to meet the current energy necessities and environmental safety.
A systematic review characterizing and clarifying intrinsic teaching challenges linked to inquiry‐based practical work
Authors: Akuma Fru Vitalis , Callaghan Ronel 
Published: October 2018

AbstractSince scientific literacy has become a key goal in science education, many people have argued in favor of the incorporation of inquiry in science education. However, scattered in the literature are extrinsic and intrinsic teaching challenges linked to the design and implementation of inquiry‐based practical work (IBPW) in secondary school science classrooms. The purpose of this systematic literature review was to characterize and clarify the intrinsic challenges. From an instructional design perspective, the characterization of the challenges yielded four primary categories. The categories consist of initiation‐phase challenges (such as unfavorable views regarding science and practical work), planning‐phase challenges (including difficulties involved in designing IBPW), implementation‐phase challenges (e.g., persuading learners to reflect on their experiences and findings), and summative evaluation‐phase challenges which include concerns linked to the grading of practical inquiry. In the different categories, the challenges are linked to gaps in various aspects of teacher competencies especially in the context of the TPACK framework. The aspects include content knowledge (CK) (such as science content and scientific inquiry); in addition to technological knowledge (TK) linked to standard technologies. Also included is pedagogic CK (including orientation toward science teaching). Moreover, some of the intrinsic challenges are linked to gaps in skills (including pervasive classroom management and practical skills); in addition to values (such as commitment). These results have theory‐, practice‐, and research‐based implications.
Supporting linguistically diverse students' science learning with dynamic visualizations through discourse‐rich practices
Authors: Ryoo Kihyun , Bedell Kristin 
Published: October 2018

AbstractCarefully scaffolded dynamic visualizations have potential to promote science learning for all students, including English language learners (ELLs) who are often underserved in mainstream science classrooms, but little is known about how to design effective scaffolding to support such diverse students' learning with dynamic visualizations. This study investigated how two forms of scaffolding embedded in dynamic visualizations, expert guidance and generating guidance, can foster ELLs' and non‐ELLs' understanding of unobservable scientific phenomena. While interacting with dynamic visualizations, students in the expert guidance condition were provided with scientifically accurate explanations to interpret visual representations, whereas students in the generating guidance condition were prompted to generate their own explanations using visual representations. The results show the significant advantage of generating guidance over expert guidance for both ELLs and non‐ELLs, although students in the generating guidance condition did not receive feedback on their generated artifacts. Analyses of video data and log data from 40 pairs revealed that each form of scaffolding affected the quantity and quality of linguistically diverse students' conversations. The results show that generating guidance enabled students, particularly ELLs, to engage in discourse‐rich practices to evaluate various sources of evidence from the visualization and compare the evidence to their alternative ideas to develop a coherent understanding of the target concepts. This study shows the unique benefits of generating guidance as an effective strategy to support linguistically diverse students' science learning with dynamic visualizations.