bluuebunny/crossref_metadata_2025_split huggingface dataset:
Old Continental Crust Underlying Juvenile Oceanic Arc: Evidence From Northern Arabian‐Nubian Shield, Egypt
Authors: Li Xian‐Hua , Abd El‐Rahman Yasser , Abu Anbar Mohamed , Li Jiao , Ling Xiao‐Xiao , Wu Li‐Guang , Masoud Ahmed E. 
Published: March 2018

AbstractThe Neoproterozoic Arabian‐Nubian Shield (ANS) is the best preserved and the largest exposed Neoproterozoic juvenile crust on Earth. While the lithology and early Sr and Nd isotopic data demonstrate that the ANS crust is overwhelmingly juvenile, pre‐ANS old zircon crystals have been increasingly recognized in the ANS igneous and sedimentary rocks, casting doubt on the “juvenility” of the ANS crust. In order to understand the origin of the old continental materials in the ANS and its roles in generation of juvenile oceanic arcs, we carry out for the first time an integrated in situ analysis of zircon U‐Pb age and Hf‐O isotopes for greywacke and felsic volcanic cobble samples from the Atud Formation in the Eastern Desert of northwestern part of the ANS. Our data indicate that the Atud Formation was deposited between ca. 720 and 700 Ma, concurrent with the production of oceanic arcs in the ANS. The Atud greywacke was derived from the erosion of a proximal arc terrane that contains numerous old continental crust materials. We identify for the first time a 755‐Ma felsic volcanic cobble from the Atud Formation that is derived from old continental materials during juvenile crust production, suggesting presence of an old continental crust substrate that underlies the ANS. Our work demonstrates that reworking of old continental crust played important roles in generation of oceanic arcs in the northwestern ANS that is likely much less juvenile than previously thought. Thus, the crustal growth rates calculated based on estimates of temporal island arc development need to be revised.
Evidence for Extending Anomalous Miocene Volcanism at the Edge of the East Antarctic Craton
Authors: Licht K. J. , Groth T. , Townsend J. P. , Hennessy A. J. , Hemming S. R. , Flood T. P. , Studinger M. 
Published: March 2018

AbstractUsing field observations followed by petrological, geochemical, geochronological, and geophysical data, we infer the presence of a previously unknown Miocene subglacial volcanic center ~230 km from the South Pole. Evidence of volcanism is from boulders of olivine‐bearing amygdaloidal/vesicular basalt and hyaloclastite deposited in a moraine in the southern Transantarctic Mountains. 40Ar/39Ar ages from five specimens plus U‐Pb ages of detrital zircon from glacial till indicate igneous activity 25–17 Ma. The likely source of the volcanism is a circular −735 nT magnetic anomaly 60 km upflow from the sampling site. Subaqueous textures of the volcanics indicate eruption beneath ice or into water at the margin of an ice mass during the early Miocene. These rocks record the southernmost Cenozoic volcanism in Antarctica and expand the known extent of the oldest lavas associated with West Antarctic Rift system. They may be an expression of lithospheric foundering beneath the southern Transantarctic Mountains.
Toward Global Mapping of Methane With TROPOMI: First Results and Intersatellite Comparison to GOSAT
Authors: Hu Haili , Landgraf Jochen , Detmers Rob , Borsdorff Tobias , Aan de Brugh Joost , Aben Ilse , Butz André , Hasekamp Otto 
Published: March 2018

AbstractThe TROPOspheric Monitoring Instrument (TROPOMI), launched on 13 October 2017, aboard the Sentinel‐5 Precursor satellite, measures reflected sunlight in the ultraviolet, visible, near‐infrared, and shortwave infrared spectral range. It enables daily global mapping of key atmospheric species for monitoring air quality and climate. We present the first methane observations from November and December 2017, using TROPOMI radiance measurements in the shortwave infrared band around 2.3 μm. We compare our results with the methane product obtained from the Greenhouse gases Observing SATellite (GOSAT). Although different spectral ranges and retrieval methods are used, we find excellent agreement between the methane products acquired from the two satellites with a mean difference of 13.6 ppb, standard deviation of 19.6 ppb, and Pearson's correlation coefficient of 0.95. Our preliminary results capture the latitudinal gradient and show expected regional enhancements, for example, in the African Sudd wetlands, with much more detail than has been observed before.
Suppression of the Polar Tongue of Ionization During the 21 August 2017 Solar Eclipse
Authors: Dang Tong , Lei Jiuhou , Wang Wenbin , Burns Alan , Zhang Binzheng , Zhang Shun‐Rong 
Published: March 2018

AbstractIt has long been recognized that during solar eclipses, the ionosphere‐thermosphere system changes greatly within the eclipse shadow, due to the rapid reduction of solar irradiation. However, the concept that a solar eclipse impacts polar ionosphere behavior and dynamics as well as magnetosphere‐ionosphere coupling has not been appreciated. In this study, we investigate the potential impact of the 21 August 2017 solar eclipse on the polar tongue of ionization (TOI) using a high‐resolution, coupled ionosphere‐thermosphere‐electrodynamics model. The reduction of electron densities by the eclipse in the middle latitude TOI source region leads to a suppressed TOI in the polar region. The TOI suppression occurred when the solar eclipse moved into the afternoon sector. The Global Positioning System total electron content observations show similar tendency of polar region total electron content suppression. This study reveals that a solar eclipse occurring at middle latitudes may have significant influences on the polar ionosphere and magnetosphere‐ionosphere coupling.
Statistical Patterns of Ionospheric Convection Derived From Mid‐latitude, High‐Latitude, and Polar SuperDARN HF Radar Observations
Authors: Thomas E. G. , Shepherd S. G. 
Published: March 2018

AbstractOver the last decade, the Super Dual Auroral Radar Network (SuperDARN) has undergone a dramatic expansion in the Northern Hemisphere with the addition of more than a dozen radars offering improved coverage at mid‐latitudes (50°–60° magnetic latitude) and in the polar cap (80°–90° magnetic latitude). In this study, we derive a statistical model of ionospheric convection (TS18) using line‐of‐sight velocity measurements from the complete network of mid‐latitude, high‐latitude, and polar radars for the years 2010–2016. These climatological patterns are organized by solar wind, interplanetary magnetic field (IMF), and dipole tilt angle conditions. We find that for weak solar wind driving conditions the TS18 model patterns are largely similar to the average patterns obtained using high‐latitude radar data only. For stronger solar wind driving the inclusion of mid‐latitude radar data at the equatorward extent of the ionospheric convection can increase the measured cross‐polar cap potential (ΦPC) by as much as 40%. We also derive an alternative model organized by the Kp index to better characterize the statistical convection under a range of magnetic activity conditions. These Kp patterns exhibit similar IMF By dependencies as the TS18 model results and demonstrate a linear increase in ΦPC with increasing Kp for a given IMF orientation. Overall, the mid‐latitude radars provide a better specification of the flows within the nightside Harang reversal region for moderate to strong solar wind driving or geomagnetic activity, while the polar radars improve the quality of velocity measurements in the deep polar cap under all conditions.
Monitoring frequency of intra‐fraction patient motion using the ExacTrac system for LINAC‐based SRS treatments
Authors: Lewis Benjamin C. , Snyder William J. , Kim Siyong , Kim Taeho 
Published: March 2018

AbstractPurposeThe aim of this study was to investigate the intra‐fractional patient motion using the ExacTrac system in LINAC‐based stereotactic radiosurgery (SRS).MethodA retrospective analysis of 104 SRS patients with kilovoltage image‐guided setup (Brainlab ExacTrac) data was performed. Each patient was imaged pre‐treatment, and at two time points during treatment (1st and 2nd mid‐treatment), and bony anatomy of the skull was used to establish setup error at each time point. The datasets included the translational and rotational setup error, as well as the time period between image acquisitions. After each image acquisition, the patient was repositioned using the calculated shift to correct the setup error. Only translational errors were corrected due to the absence of a 6D treatment table. Setup time and directional shift values were analyzed to determine correlation between shift magnitudes as well as time between acquisitions.ResultsThe average magnitude translation was 0.64 ± 0.59 mm, 0.79 ± 0.45 mm, and 0.65 ± 0.35 mm for the pre‐treatment, 1st mid‐treatment, and 2nd mid‐treatment imaging time points. The average time from pre‐treatment image acquisition to 1st mid‐treatment image acquisition was 7.98 ± 0.45 min, from 1st to 2nd mid‐treatment image was 4.87 ± 1.96 min. The greatest translation was 3.64 mm, occurring in the pre‐treatment image. No patient had a 1st or 2nd mid‐treatment image with greater than 2 mm magnitude shifts.ConclusionThere was no correlation between patient motion over time, in direction or magnitude, and duration of treatment. The imaging frequency could be reduced to decrease imaging dose and treatment time without significant changes in patient position.
Physical validation of UF‐RIPSA: A rapid in‐clinic peak skin dose mapping algorithm for fluoroscopically guided interventions
Authors: Borrego David , Marshall Emily L. , Tran Trung , Siragusa Daniel A. , Bolch Wesley E. 
Published: March 2018

AbstractPurposeThe purpose of this study was to experimentally validate UF‐RIPSA, a rapid in‐clinic peak skin dose mapping algorithm developed at the University of Florida using optically stimulated luminescent dosimeters (OSLDs) and tissue‐equivalent phantoms.MethodsThe OSLDs used in this study were InLightTM Nanodot dosimeters by Landauer, Inc. The OSLDs were exposed to nine different beam qualities while either free‐in‐air or on the surface of a tissue equivalent phantom. The irradiation of the OSLDs was then modeled using Monte Carlo techniques to derive correction factors between free‐in‐air exposures and more complex irradiation geometries. A grid of OSLDs on the surface of a tissue equivalent phantom was irradiated with two fluoroscopic x ray fields generated by the Siemens Artis zee bi‐plane fluoroscopic unit. The location of each OSLD within the grid was noted and its dose reading compared with UF‐RIPSA results.ResultsWith the use of Monte Carlo correction factors, the OSLD's response under complex irradiation geometries can be predicted from its free‐in‐air response. The predicted values had a percent error of −8.7% to +3.2% with a predicted value that was on average 5% below the measured value. Agreement within 9% was observed between the values of the OSLDs and RIPSA when irradiated directly on the phantom and within 14% when the beam first traverses the tabletop and pad.ConclusionsThe UF‐RIPSA only computes dose values to areas of irradiated skin determined to be directly within the x ray field since the algorithm is based upon ray tracing of the reported reference air kerma value, with subsequent corrections for air‐to‐tissue dose conversion, x ray backscatter, and table/pad attenuation. The UF‐RIPSA algorithm thus does not include the dose contribution of scatter radiation from adjacent fields. Despite this limitation, UF‐RIPSA is shown to be fairly robust when computing skin dose to patients undergoing fluoroscopically guided interventions.
Fully automated searching for the optimal VMAT jaw settings based on Eclipse Scripting Application Programming Interface (ESAPI) and RapidPlan knowledge‐based planning
Authors: Huang Yuliang , Yue Haizhen , Wang Meijiao , Li Sha , Zhang Jian , Liu Zhuolun , Zhang Yibao 
Published: March 2018

AbstractPurposeEclipse treatment planning system has not been able to optimize the jaw positions for Volumetric Modulated Arc Therapy (VMAT). The arbitrary and planner‐dependent jaw placements define the maximum field size within which multi‐leaf‐collimator (MLC) sequences can be optimized to modulate the beam. Considering the mechanical constraints of MLC transitional speed and range, suboptimal X jaw settings may impede the optimization or undermine the deliverability. This work searches optimal VMAT jaw settings automatically based on Eclipse Scripting Application Programming Interface (ESAPI) and RapidPlan knowledge‐based planning.Methods and materialsUsing an ESAPI script, the X jaws of rectal VMAT plans were initially set to conform the planning‐target‐volume (PTV), and were gradually extended toward the isocenter (PTV center) in 5–7 mm increments. Using these jaw pairs, 592 plans were automatically created for 10 patients and quantitatively evaluated using a comprehensive scoring function. A published RapidPlan model was evoked by ESAPI to generate patient‐specific optimization objectives without manual intervention. All candidate plans were first stored as text files to save storage space, and only the best, worst, and conformal plans were consequently recreated for comparison.ResultsAlthough RapidPlan estimates dose‐volume histogram (DVH) based on individual anatomy, the geometry‐based expected dose (GED) algorithm does not recognize different jaw settings but uses PTV‐conformal jaws as default; hence, identical DVHs were observed regardless of planner‐defined jaws. Therefore, ESAPI finalized dose‐volume calculation and eliminated the plans with unacceptable hotspots before comparison. The plan quality varied dramatically with different jaw settings. Trade‐offs among different organs‐at‐risk (OARs) were collectively considered by the proposed scoring method, which identified the best and worst plans correctly. The plans using conformal jaws were neither the best nor the worst of all candidates.ConclusionsVMAT plans using optimal jaw locations can be created automatically using ESAPI and RapidPlan. Conformal jaws are not the optimal choice.
Quantification of beam steering with an ionization chamber array
Authors: Gao Song , Balter Peter A. , Tran Benjamin , Rose Mark , Simon William E. 
Published: March 2018

AbstractRoutine quality assurance for linear accelerators (linacs) usually involves verification of beam steering with a water scanning system. We established a beam steering procedure that uses a 2D ionization chamber array (ICA) and verified the equivalence of beam symmetry between the ICA and a water scanning system. The ICA calibration accuracy, reproducibility and stability were evaluated and the uncertainty in the measurement of beam symmetry due to the array calibration was examined. Forty‐five photon beams and 80 electron beams across 7 Varian C‐series and 4 TrueBeam linacs were steered in the radial and transverse directions using an ICA. After beam steering, profiles were re‐measured using the ICA and in‐water using a 3D Scanner (3DS). Beam symmetries measured with the ICA and 3DS were compared by (a) calculating the difference in point‐by‐point symmetry, (b) plotting the histogram distribution of the symmetry differences, and (c) comparing ICA and 3DS differences with their respective Varian symmetry protocol analysis. Array calibrations from five different occurrences (2012 to 2016) over six different beams reproduced within 0.5%. The uncertainty in beam symmetry was less than 0.5% due to the uncertainties in the array calibration. After all beams were steered using the ICA, the point‐by‐point symmetry differences between ICA and 3DS at the off‐axis positions of 20% and 80% of field size for all beam profiles indicated that 95% of point‐by‐point symmetry comparisons agreed within 0.7%, and 100% agreed within 1.0%; after steering with the ICA 97.8% of photon beam profiles (88 of 90) and 97.5% of electron beam profiles (156 of 160) had symmetry within 1% when measured with the 3DS. All photon and electron beam profiles had symmetry within 1.1% and 1.2%, respectively, for profiles measured with the 3DS. Our data demonstrate that a calibrated ICA can be used to steer photon and electron beams achieving beam symmetry within 1% when re‐measured with a 3D water scanning system.
Genomic analysis identifies masqueraders of full‐term cerebral palsy
Authors: Takezawa Yusuke , Kikuchi Atsuo , Haginoya Kazuhiro , Niihori Tetsuya , Numata‐Uematsu Yurika , Inui Takehiko , Yamamura‐Suzuki Saeko , Miyabayashi Takuya , Anzai Mai , Suzuki‐Muromoto Sato , Okubo Yukimune , Endo Wakaba , Togashi Noriko , Kobayashi Yasuko , Onuma Akira , Funayama Ryo , Shirota Matsuyuki , Nakayama Keiko , Aoki Yoko , Kure Shigeo 
Published: March 2018

AbstractObjectiveCerebral palsy is a common, heterogeneous neurodevelopmental disorder that causes movement and postural disabilities. Recent studies have suggested genetic diseases can be misdiagnosed as cerebral palsy. We hypothesized that two simple criteria, that is, full‐term births and nonspecific brain MRI findings, are keys to extracting masqueraders among cerebral palsy cases due to the following: (1) preterm infants are susceptible to multiple environmental factors and therefore demonstrate an increased risk of cerebral palsy and (2) brain MRI assessment is essential for excluding environmental causes and other particular disorders.MethodsA total of 107 patients—all full‐term births—without specific findings on brain MRI were identified among 897 patients diagnosed with cerebral palsy who were followed at our center. DNA samples were available for 17 of the 107 cases for trio whole‐exome sequencing and array comparative genomic hybridization. We prioritized variants in genes known to be relevant in neurodevelopmental diseases and evaluated their pathogenicity according to the American College of Medical Genetics guidelines.ResultsPathogenic/likely pathogenic candidate variants were identified in 9 of 17 cases (52.9%) within eight genes: CTNNB1, CYP2U1, SPAST, GNAO1, CACNA1A, AMPD2, STXBP1, and SCN2A. Five identified variants had previously been reported. No pathogenic copy number variations were identified. The AMPD2 missense variant and the splice‐site variants in CTNNB1 and AMPD2 were validated by in vitro functional experiments.InterpretationThe high rate of detecting causative genetic variants (52.9%) suggests that patients diagnosed with cerebral palsy in full‐term births without specific MRI findings may include genetic diseases masquerading as cerebral palsy.
Antibodies against cell adhesion molecules and neural structures in paraneoplastic neuropathies
Authors: Siles Ana M. , Martínez‐Hernández Eugenia , Araque Josefa , Diaz‐Manera Jordi , Rojas‐Garcia Ricard , Gallardo Eduard , Illa Isabel , Graus Francesc , Querol Luis 
Published: March 2018

AbstractObjectiveParaneoplastic neurological syndromes (PNS) are rare neurological disorders in which ectopic expression of neural antigens by a tumor results in an autoimmune attack against the nervous system. Onconeural antibodies not only guide PNS diagnosis but may also help detecting underlying malignancies. Our project aims to uncover new potential antibodies in paraneoplastic neuropathies (PN).MethodsThirty‐four patients fulfilling diagnostic criteria of possible (n = 9; 26.5%) and definite (n = 25; 73.5%) PN without onconeural antibodies and 28 healthy controls were included in our study. Sera were tested for known antibodies against neural cell adhesion molecules and screened for novel IgG and IgM reactivities against nerve components: dorsal root ganglia (DRG) neurons, motor neurons, and Schwann cells. Patients showing autoantibodies against any of these cell types were used for immunoprecipitation (IP) studies.ResultsOverall, 9 (26.5%) patients showed significant reactivity against DRG neurons, motor neurons, or Schwann cells, whereas 5 (17.9%) healthy controls only showed moderate reactivity. Compared with control sera, serum samples from patients with paraneoplastic sensory‐motor neuropathies had a higher frequency of IgM antibodies against Schwann cells (0% vs. 40%; P = 0.0028). No novel antigens were identified from our IP experiments. Antibodies against the neural adhesion molecules CNTN1, NF155, NF140, NF186, NCAM1, L1CAM, and the CNTN1/CASPR1 complex were not detected in patients with PN. One (2.9%) patient with CIDP and thymoma had CASPR2 antibodies.InterpretationAlmost 30% of patients with PN harbor antibodies targeting neural structures, suggesting that novel neoplasm‐associated antigens remain to be discovered.
Gout Severity, Socioeconomic Status, and Work Absence: A Cross‐Sectional Study in Primary Care
Authors: Bowen‐Davies Zachary , Muller Sara , Mallen Christian D. , Hayward Richard A. , Roddy Edward 
Published: March 2018

ObjectiveTo examine the association between gout severity and socioeconomic status (SES) and gout severity and work absence.MethodsPostal questionnaires were sent to adult patients who were registered with 20 general practices and who had consultations regarding gout or had been prescribed allopurinol or colchicine in the preceding 2 years. Gout severity was defined using the following proxy measures: number of attacks, history of oligoarticular/polyarticular attacks, disease duration, and allopurinol use. SES was defined using the English index of multiple deprivation (area level) and using self‐reported educational attainment (individual level). Work absence was defined as taking time off from work in the past 6 months because of gout. Adjusted odds ratios (ORadj; 95% confidence intervals [95% CIs]) were calculated using logistic regression models (adjusted for age, sex, body mass index, gout severity, and comorbidities).ResultsA total of 1,184 completed questionnaires were returned. The mean age of patients was 65.6 years, and 84% were male. Not having attended further education (“further education” is defined as attendance after the statutory minimum school‐leaving age of 16 years) was associated with having had ≥2 gout attacks in the last year (ORadj 0.54 [95% CI 0.36–0.81]) and oligoarticular/polyarticular attacks (ORadj 0.72 [95% CI 0.50–1.05]). Lower area–level deprivation was associated with fewer attacks (≥2) (ORadj 0.71 [95% CI 0.51–0.98]). Work absence was associated with having had ≥2 gout attacks in the last year (ORadj 2.91 [95% CI 1.22– 6.92]), oligoarticular/polyarticular attacks (ORadj 3.10 [95% CI 1.46–6.61]), and shorter disease duration (>18 years) (ORadj 0.13 [95% CI 0.03–0.50]).ConclusionGout severity was associated with individual‐level deprivation, countering the historic and negative perception of gout as a “rich man's disease.” The association of gout severity with work absence reinforces the argument for earlier urate‐lowering therapy to prevent attacks from becoming frequent and debilitating.