bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Shock Tube Study of H Atom Addition to Cyclopentene
Authors: Manion Jeffrey A. , Awan Iftikhar A. 
Published: February 2018

ABSTRACTWe report shock tube studies of the kinetics of H atom addition to cyclopentene and modeling of the subsequent decomposition of cyclopentyl. Hydrogen atoms were generated with thermal precursors in dilute mixtures of cyclopentene and a reference compound in argon. Addition of H to the double bond leads to a cyclopentyl radical that rapidly ring opens and decomposes to ethene and allyl radical. The process was monitored by postshock gas chromatographic analysis of ethene and rate constants determined relative to H atom displacement of methyl from 1,3,5‐trimethylbenzene (135TMB). At 863–1167 K and 160–370 kPa, we find urn:x-wiley:05388066:kin21150:equation:kin21150-math-0001 and, with , we obtain urn:x-wiley:05388066:kin21150:equation:kin21150-math-0003Using experimental values of about 3:1 for the ratio of C─C to C─H beta scission in cyclopentyl radicals and a corresponding transition‐state‐theory/Rice‐Ramsberger‐Kassel‐Marcus (TST/RRKM) model, the high‐pressure rate expression for addition of H to cyclopentene at 863–1167 K is derived as urn:x-wiley:05388066:kin21150:equation:kin21150-math-0004Combined with literature results from lower temperatures and a fitted TST model, the rate expression between 298 and 2000 K is determined as urn:x-wiley:05388066:kin21150:equation:kin21150-math-0005Results are compared with related systems. Near 1000 K, our data require a minimum value of 1.5 for branching between beta C─C and C─H scission in cyclopentyl radicals to maintain established trends in H addition rates. This conflicts with current computed values and those used in existing kinetics models of cyclopentane combustion. We additionally report and discuss minor observed channels in the decomposition of cyclopentene, including formation of 1,4‐pentadiene, (E/Z)‐1,3‐pentadiene, 1,3‐butadiene, and the direct elimination of H2 from cyclopentene to give cyclopentadiene.
Velocity‐amplified microbial respiration rates in the lower Amazon River
Authors: Ward Nicholas D. , Sawakuchi Henrique O. , Neu Vania , Less Diani F. S. , Valerio Aline M. , Cunha Alan C. , Kampel Milton , Bianchi Thomas S. , Krusche Alex V. , Richey Jeffrey E. , Keil Richard G. 
Published: February 2018

AbstractMost measurements of respiration rates in large tropical rivers do not account for the influence of river flow conditions on microbial activity. We developed a ship‐board spinning incubation system for measuring O2 drawdown under different rotation velocities and deployed the system along the lower Amazon River during four hydrologic periods. Average respiration rates in incubation chambers rotated at 0.22 m s−1 and 0.66 m s−1 were 1.4 and 2.4 times higher than stationary chambers, respectively. On average, depth‐integrated respiration rates in chambers spun at 0.22 m s−1 and 0.66 m s−1 accounted for 64% ± 22% and 104% ± 36% of CO2 outgassing rates, respectively, in mainstem sites. Continuous measurements of in situ pCO2 were also made along with cross‐channel profiles of river velocity. A positive correlation between river velocity and pCO2 was observed along the lower river (r2 = 0.67–0.96) and throughout a tidal cycle.
Increasing dominance of terrigenous organic matter in circumpolar freshwaters due to permafrost thaw
Authors: Wauthy Maxime , Rautio Milla , Christoffersen Kirsten S. , Forsström Laura , Laurion Isabelle , Mariash Heather L. , Peura Sari , Vincent Warwick F. 
Published: February 2018

AbstractClimate change and permafrost thaw are unlocking the vast storage of organic carbon held in northern frozen soils. Here, we evaluated the effects of thawing ice‐rich permafrost on dissolved organic matter (DOM) in freshwaters by optical analysis of 253 ponds across the circumpolar North. For a subset of waters in subarctic Quebec, we also quantified the contribution of terrestrial sources to the DOM pool by stable isotopes. The optical measurements showed a higher proportion of terrestrial carbon and a lower algal contribution to DOM in waters affected by thawing permafrost. DOM composition was largely dominated (mean of 93%) by terrestrial substances at sites influenced by thawing permafrost, while the terrestrial influence was much less in waterbodies located on bedrock (36%) or with tundra soils unaffected by thermokarst processes (42%) in the catchment. Our results demonstrate a strong terrestrial imprint on freshwater ecosystems in degrading ice‐rich permafrost catchments, and the likely shift toward increasing dominance of land‐derived organic carbon in waters with ongoing permafrost thaw.
Bohr radius for locally univalent harmonic mappings
Authors: Kayumov Ilgiz R , Ponnusamy Saminathan , Shakirov Nail 
Published: February 2018

AbstractWe consider the class of all sense‐preserving harmonic mappings of the unit disk , where h and g are analytic with , and determine the Bohr radius if any one of the following conditions holds:

h is bounded in .
h satisfies the condition in with .
both h and g are bounded in .
h is bounded and .
We also consider the problem of determining the Bohr radius when the supremum of the modulus of the dilatation of f in is strictly less than 1. In addition, we determine the Bohr radius for the space of analytic Bloch functions and the space of harmonic Bloch functions. The paper concludes with two conjectures.
Age‐ and CGG repeat‐related slowing of manual movement in fragile X carriers: A prodrome of fragile X‐associated tremor ataxia syndrome?
Authors: Shickman Ryan , Famula Jessica , Tassone Flora , Leehey Maureen , Ferrer Emilio , Rivera Susan M. , Hessl David 
Published: February 2018

ABSTRACTBackgroundFragile X premutation carriers are at increased risk for fragile X‐associated tremor ataxia syndrome (FXTAS), but to date we know little about prediction of onset and rate of progression and even less about treatment of this neurodegenerative disease. Thus, the longitudinal study of carriers, and the identification of potential biomarkers and prodromal states, is essential. Here we present results of baseline assessments from an ongoing longitudinal project.MethodsThe cohort consisted of 73 men, 48 with the fragile X mental retardation 1 (FMR1) premutation (55‐200 cytosine‐cytosine‐guanine or CGG repeats) and 25 well‐matched controls (< 40 repeats) aged between 40 and 75 years. At enrollment, none met criteria for FXTAS or had any clinically significant tremor or ataxia by blinded neurological examination. The battery consisted of measures of visual memory, spatial working memory, response inhibition, motor speed and control, planning and problem solving, sustained attention, and a standardized movement disorder evaluation.ResultsContrary to expectations, there were no significant differences between premutation carriers and controls on any measure of executive function. However, the premutation carriers had significantly longer manual movement and reaction times than controls, and the significant interaction between CGG repeat and age revealed the slowest movement times among older carriers with higher CGG repeat alleles. A subset of premutation carriers had marginally lower scores on the ataxia evaluation, and they performed no differently from controls on the parkinsonism assessment.ConclusionEarly‐developing cerebellar or fronto‐motor tract white matter changes, previously documented in MRI studies, may underlie motor slowing that occurs before clinically observable neurological symptoms associated with FXTAS. © 2018 International Parkinson and Movement Disorder Society
Adiposity Associated Plasma Linoleic Acid is Related to Demographic, Metabolic Health and Haplotypes of FADS1/2 Genes in Irish Adults
Authors: Li Kaifeng , Brennan Lorraine , Bloomfield Jack F. , Duff Dan J. , McNulty Breige A. , Flynn Albert , Walton Janette , Gibney Michael J. , Nugent Anne P. 
Published: February 2018

ScopeThis study examines to what extent plasma linoleic acid (LA) is modified by adiposity, and explores any association between plasma LA, demographics, dietary intakes, markers of metabolic health, and haplotypes of the fatty acid desaturase (FADS) 1/2 genes.Methods and resultsA total of 820 participants with fasting blood samples from the Irish National Adult Nutrition Survey are studied. Plasma fatty acids are determined using GC–MS. Fifteen SNPs of FADS 1/2 genes are genotyped. Plasma LA decreases, while γ‐linoleic acid and dihomo‐γ‐linoleic acid increases in overweight/obese participants (p ≤ 0.002). Participants in the highest quartile of plasma LA show decreased plasma markers of de novo lipogenesis, insulin resistance, and of inflammation (TNF‐α, PAI‐1) (p ≤ 0.005). Adiposity (waist circumference and body fat) is strongly inversely associated with plasma LA accounting for 11.8% of variance observed, which is followed by FADS1/2 haplotypes (3.9%), quantity and quality of carbohydrate intakes (3.8%), dietary PUFA intakes (3.7%), systolic blood pressure (3.6%), and age (3.2%).ConclusionPlasma LA is inversely associated with adiposity, followed by haplotypes of FADS1/2 genes, carbohydrate intakes, and dietary PUFA intakes. The association observed between plasma LA and adiposity may be linked to decreased de novo lipogenesis, insulin resistance, and inflammation.
A dedicated breast‐PET/CT scanner: Evaluation of basic performance characteristics
Authors: Raylman Raymond R. , Van Kampen Will , Stolin Alexander V. , Gong Wenbo , Jaliparthi Gangadhar , Martone Peter F. , Smith Mark F. , Sarment David , Clinthorne Neal H. , Perna Mark 
Published: February 2018

PurposeApplication of advanced imaging techniques, such as PET and x ray CT, can potentially improve detection of breast cancer. Unfortunately, both modalities have challenges in the detection of some lesions. The combination of the two techniques, however, could potentially lead to an overall improvement in diagnostic breast imaging. The purpose of this investigation is to test the basic performance of a new dedicated breast‐PET/CT.MethodsThe PET component consists of a rotating pair of detectors. Its performance was evaluated using the NEMA NU4‐2008 protocols. The CT component utilizes a pulsed x ray source and flat panel detector mounted on the same gantry as the PET scanner. Its performance was assessed using specialized phantoms. The radiation dose to a breast during CT imaging was explored by the measurement of free‐in‐air kerma and air kerma measured at the center of a 16 cm‐diameter PMMA cylinder. Finally, the combined capabilities of the system were demonstrated by imaging of a micro‐hot‐rod phantom.ResultsOverall, performance of the PET component is comparable to many pre‐clinical and other dedicated breast‐PET scanners. Its spatial resolution is 2.2 mm, 5 mm from the center of the scanner using images created with the single‐sliced‐filtered‐backprojection algorithm. Peak NECR is 24.6 kcps; peak sensitivity is 1.36%; the scatter fraction is 27%. Spatial resolution of the CT scanner is 1.1 lp/mm at 10% MTF. The free‐in‐air kerma is 2.33 mGy, while the PMMA‐air kerma is 1.24 mGy. Finally, combined imaging of a micro‐hot‐rod phantom illustrated the potential utility of the dual‐modality images produced by the system.ConclusionThe basic performance characteristics of a new dedicated breast‐PET/CT scanner are good, demonstrating that its performance is similar to current dedicated PET and CT scanners. The potential value of this system is the capability to produce combined duality‐modality images that could improve detection of breast disease. The next stage in development of this system is testing with more advanced phantoms and human subjects.
Model‐Based Reactor Design to Control Hyperbranched Polymer Architecture
Authors: Tobita Hidetaka 
Published: February 2018

AbstractA Monte Carlo simulation method, based on the random sampling technique in which a large number of polymers are sampled from the final product, is proposed for the continuous tanks‐in‐series process. The effect of the sequence of tanks with different sizes is considered for the irreversible step polymerization of AB2‐type monomer. It is found that the tank sequence starting from a large tank followed by a number of smaller tanks is suitable to produce compact hyperbranched polymers, whose mean‐square radii of gyration are much smaller than those formed in batch polymerization. Analytic formulas of the average molecular weights are presented for the tanks‐in‐series processes, including the post‐processes to make the molecular weight distribution narrower by removing residual monomer and by introducing multifunctional core molecules. The present investigation enhances fundamental knowledge that would be useful for the model‐based reactor design to control detailed branched architecture of the hyperbranched polymers.
Transverse slot antennas for high field MRI
Authors: Alon Leeor , Lattanzi Riccardo , Lakshmanan Karthik , Brown Ryan , Deniz Cem M. , Sodickson Daniel K. , Collins Christopher M. 
Published: February 2018

PurposeIntroduce a novel coil design using an electrically long transversely oriented slot in a conductive sheet.Theory and MethodsTheoretical considerations, numerical simulations, and experimental measurements are presented for transverse slot antennas as compared with electric dipole antennas.ResultsSimulations show improved central and average transmit and receive efficiency, as well as larger coverage in the transverse plane, for a single slot as compared to a single dipole element. Experiments on a body phantom confirm the simulation results for a slot antenna relative to a dipole, demonstrating a large region of relatively high sensitivity and homogeneity. Images in a human subject also show a large imaging volume for a single slot and six slot antenna array. High central transmit efficiency was observed for slot arrays relative to dipole arrays.ConclusionTransverse slots can exhibit improved sensitivity and larger field of view compared with traditional conductive dipoles. Simulations and experiments indicate high potential for slot antennas in high field MRI. Magn Reson Med 80:1233–1242, 2018. © 2018 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
Deep learning approaches for detection and removal of ghosting artifacts in MR spectroscopy
Authors: Kyathanahally Sreenath P. , Döring André , Kreis Roland 
Published: February 2018

PurposeTo make use of deep learning (DL) methods to detect and remove ghosting artifacts in clinical magnetic resonance spectra of human brain.MethodsDeep learning algorithms, including fully connected neural networks, deep‐convolutional neural networks, and stacked what‐where auto encoders, were implemented to detect and correct MR spectra containing spurious echo ghost signals. The DL methods were trained on a huge database of simulated spectra with and without ghosting artifacts that represent complex variations of ghost‐ridden spectra, transformed to time‐frequency spectrograms. The trained model was tested on simulated and in vivo spectra.ResultsThe preliminary results for ghost detection are very promising, reaching almost 100% accuracy, and the DL ghost removal methods show potential in simulated and in vivo spectra, but need further refinement and quantitative testing.ConclusionsGhosting artifacts in spectroscopy are problematic, as they superimpose with metabolites and lead to inaccurate quantification. Detection and removal of ghosting artifacts using traditional machine learning approaches with feature extraction/selection is difficult, as ghosts appear at different frequencies. Here, we show that DL methods perform extremely well for ghost detection if the spectra are treated as images in the form of time‐frequency representations. Further optimization for in vivo spectra will hopefully confirm their “ghostbusting” capacity. Magn Reson Med 80:851–863, 2018. © 2018 International Society for Magnetic Resonance in Medicine.
Performance of Instream Jordan–Scotty Salmon Egg Incubators Under Different Installation and Sedimentation Conditions
Authors: Purchase Craig F. , Palm-Flawd Brittany , Charron Louis 
Published: February 2018

Abstract
Fish stocking, in which natural populations are supplemented with progeny through some unnatural means, is widespread and takes many forms. Long-term benefits of population viability are generally greatest when individuals are subjected to as little artificial rearing as possible. For salmonids, instream incubation enables embryo exposure to natural conditions during a critical developmental period. The Jordan–Scotty incubator is a new tool that facilitates the ability to conduct instream incubation on a semi-large scale. However, the performance of this type of incubator is affected by sedimentation. We quantified sediment accumulation within Jordan–Scotty incubators when installed using four potential methods in a blocked design that eliminated confounding space–time variables. Although sediment accumulation was highly variable, there appeared to be no benefit in taking the extra effort to install the incubators under gravel as recommended by the manufacturer. Incubator exposure to streamflow can be achieved in several ways and reduces sedimentation. We recommend the use of pre-installed plastic milk crates as incubator receptacles.
Growth faltering in a skeletal sample of enslaved nonadult Africans found at Lagos, Portugal (15th–17th centuries)
Authors: Wasterlain S. N. , Costa A. , Ferreira M. T. 
Published: February 2018

AbstractThe aim of this study is to analyse the growth of a sample of 31 nonadult individuals buried in an unusual way in Valle da Gafaria (Lagos, Portugal) between the 15th and 17th centuries. The archaeological and historical context of the skeletal collection (N = 158), the morphological traits of the skulls, and the presence of intentionally modified teeth in some individuals led to the conclusion that they were African slaves. The study of past populations' growth has been an essential component of the bioanthropological investigations because it is a good indicator of the health state and environment conditions in which human populations have lived. Attending to the hypothesis that differences between skeletal and dental age estimations are indicative of growth delay, it is pertinent to understand if these enslaved nonadult individuals were exposed to harsh environmental conditions. Dental age was estimated on the basis of dental development, that is, dental calcification and the sequence of formation and eruption of teeth. Skeletal age was evaluated in accordance to the long bones lengths. Non‐specific stress indicators, namely, cribra orbitalia, cribra humeralis, cribra femoralis, porotic hyperostosis, and enamel hypoplasia, were considered as markers of physiological disturbances. The age estimates obtained by the two dental methods were consistent in 79.2% of the individuals. On the other hand, the estimates obtained by osteometric and dental methods were consistent in 75.9% (osteometric vs. sequence of formation and eruption of teeth) and 65.2% (osteometric vs. dental calcification), the osteometric providing younger ages. The relatively low concordance between the age estimations was corroborated by the Cohen's Kappa coefficients. These results along with the high frequencies of cribra orbitalia (87.0%), cribra femoralis (85.7%), cribra humeralis (44.4%), porotic hyperostosis (43.3%), and enamel hypoplasia (70.0%) make evident the difficulties experienced by these individuals during their short lives.
Attempts to Lose Weight Among US Children: Importance of Weight Perceptions from Self, Parents, and Health Professionals
Authors: Ling Jiying , Stommel Manfred , Choi Seung Hee 
Published: February 2018

ObjectiveThe objective of this study was to investigate how perceptions of weight by children themselves, parents, and health professionals influence children's persistent attempts to lose weight.MethodsThe sample included 4,914 children aged 8 to 15 years from the 2005 to 2014 National Health and Nutrition Examination Survey (representing 20.7 million children). Data were analyzed using logistic regression models.ResultsAbout 34.2% never made an effort to lose weight, whereas 28.2% made persistent attempts to lose weight. Children's persistent attempts to lose weight were highly related to their own BMI percentile. Children's self‐perceptions of overweight increased the odds of persistent attempts to lose weight more than sevenfold. Health professionals’ perceptions that children were overweight increased the odds of persistent attempts to lose weight almost threefold. However, parents’ perceptions of children as overweight had a relatively small though significant influence on children's attempts to lose weight.ConclusionsAs perceptions of children's weight status play big roles in children's attempts to lose weight, interventions focusing on increasing accuracy of perceptions may help promote healthy weight loss efforts. Although parents are key agents in controlling their children's weight gain, especially among minority school‐aged children, the study findings also emphasize the greater importance of health professionals on children's attempts to lose weight across different racial/ethnic groups.
Real‐time monitoring by proton relaxometry of radical polymerization reactions of acrylamide in aqueous solution
Authors: Rodrigues Elton Jorge da Rocha , Neto Roberto Pinto Cucinelli , Sebastião Pedro José Oliveira , Tavares Maria Inês Bruno 
Published: February 2018

AbstractThe potential of time‐domain nuclear magnetic resonance (TD‐NMR) for the real‐time monitoring of solution radical polymerizations is demonstrated. A model system composed of a redox‐pair initiator system, acrylamide as monomer and water as solvent was investigated. A second‐generation continuous wave free precession technique was employed to measure the longitudinal relaxation time constant (T1) of the samples throughout the polymerization reactions. This parameter was shown to be sensitive to the reactant feed free‐radical enhancement of the water molecule relaxation time, making it a good probe to monitor monomer conversion in real time in an automated, non‐destructive fashion. It was found that the T1 value was better than the transverse relaxation time constant (T2) for describing the evolution of the polymerization reactions, due to its greater sensitivity to paramagnetic effects. The TD‐NMR signal variation observed was linked to the formation, propagation and termination steps of the radical polymerization kinetics scheme. These first results may contribute to the application of real‐time monitoring of radical polymerization reactions employing low‐cost and robust TD‐NMR spectrometers. © 2018 Society of Chemical Industry