bluuebunny/crossref_metadata_2025_split huggingface dataset:
Shear Wave Elastography in Placental Dysfunction
Authors: Cimsit Canan , Yoldemir Tevfik , Akpinar Ihsan Nuri 
Published: December 2014

ObjectivesThe aim of this study was to determine whether shear wave elastography of the placenta differs between normal pregnancies and pregnancies complicated by preeclampsia between 20 and 23 weeks' gestation.MethodsA prospective study was performed with 204 consecutive singleton pregnancies that had routine anomaly scanning between 20 and 23 weeks' gestation. One hundred twenty‐nine of these patients were examined with shear wave elastography; 101 women who had clinically normal pregnancies with normal fetal biometric measurements and normal deliveries without any perinatal complications formed group A, and 28 women who had a clinical diagnosis of early‐onset preeclampsia before anomaly scanning formed group B. Women with either posterior placentations (n = 63) or other obstetric disorders (n = 12) were excluded from the study.ResultsShear wave elastographic values for group B were significantly higher than those for group A (P < .05). No statistically significant difference was found between the elasticity values measured at the center or edge of the placenta (P > .05).ConclusionsShear wave elastography differentiates between the placental elasticity of normal pregnancies and pregnancies complicated by preeclampsia when performed during the second trimester. As a new method for tissue characterization, shear wave elastography is useful for evaluation of placental function and can be used as a supplement to existing methods for prediction of preeclampsia.
Benefits of Sonography in Diagnosing Suspected Uncomplicated Acute Diverticulitis
Authors: King Welfur C. , Shuaib Waqas , Vijayasarathi Arvind , Fajardo Carlos G. , Cabrera Waldo E. , Costa Juan L. 
Published: December 2014

ObjectivesDespite evidence demonstrating equivalent accuracy of sonography and computed tomography (CT) in the workup of mild/uncomplicated acute diverticulitis, CT is overwhelmingly performed as the initial diagnostic test, particularly in the acute setting. Our study evaluated potential radiation and turnaround time savings associated with performing sonography instead of CT as the initial diagnostic examination in the workup of suspected uncomplicated acute diverticulitis.MethodsWe retrospectively reviewed medical records from January 2010 to December 2012 for patients presenting with clinical symptoms of acute diverticulitis. Patients were categorized as a whole and subgrouped by age (>40 and <40 years). A modified Hinchey classification (Am Surg 1999; 65:632–636) was used to stage the severity of the disease. The effective radiation dose was calculated by multiplying the dose length product from the scanner by the standard conversion coefficient (k= 0.0021 mSv/mGy × cm). The turnaround time for patients was calculated as the time the examination was ordered by the emergency department physician or staff to the time the report was finalized.ResultsOur study included 253 patients (172 male and 81 female; mean age ± SD, 50.2 ± 11.7 years; 132 >40 years and 121 <40 years). The distribution of patients by the modified Hinchey classification was 210 (stages 0 and 1a), 26 (stages 1b and 2), 17 (stages 3 and 4), 0 (fistula), and 0 (obstruction). The estimated CT radiation dose per patient was 21 ± 5.2 mSv. Mean turnaround times for CT and sonography were 138.5 ± 76.9 and 51.3 ± 44 minutes, respectively.ConclusionsSonography is a lower‐cost, faster, and radiation‐free alternative that measures up to the diagnostic standards of CT for management of suspected mild or uncomplicated acute diverticulitis.
Nonsurgical Management of Childhood Intussusception
Authors: Sanchez Thomas Ray , Doskocil Brandon , Stein-Wexler Rebecca 
Published: December 2014

ObjectivesThe purpose of this study was to compare the effectiveness of sonography and fluoroscopy in guiding intussusception reduction and evaluate possible complications for each procedure.MethodsA retrospective analysis was performed by reviewing 31 cases of intussusception diagnosed and managed between January 2009 and January 2014 at the University of California, Davis Children's Hospital, after obtaining approval from the Institutional Review Board. To eliminate other confounding factors related to technique and experience, only cases performed by 2 pediatric radiologists who exclusively used either fluoroscopy or sonography were compared.ResultsFourteen patients (age range, 6–35 months) were treated by sonographic guidance using saline, and another 17 patients (age range, 2–57 months) were treated by fluoroscopy using either air or a water‐soluble contrast agent. All 14 patients (100%) who underwent sonographically guided reduction were successfully treated without complications. Fourteen of the 17 patients (82%) who underwent fluoroscopic guidance had successful reductions. One complication of perforation was documented.ConclusionsSonography and fluoroscopy are equally effective in the nonsurgical management of childhood intussusception. The absence of ionizing radiation and better visualization of possible pathologic lead points makes sonography the ideal method.
A New Simple Technique for 3‐Dimensional Sonographic Assessment of the Pelvic Floor Muscles
Authors: Youssef Aly , Montaguti Elisa , Sanlorenzo Olimpia , Cariello Luisa , Awad Elsayed Elbadawy , Pacella Giuseppina , Ghi Tullio , Pilu Gianluigi , Rizzo Nicola 
Published: December 2014

ObjectivesThe purpose of this study was to assess the reproducibility of a new technique for 3‐dimensional (3D) pelvic floor sonography: OmniView combined with Volume Contrast Imaging (VCI; GE Healthcare, Kretz Ultrasound, Zipf, Austria) for pelvic hiatal area measurement. In addition, we aimed to study the intermethod agreement between the new technique and the standard 3D rendering method.MethodsWe acquired a static 3D sonographic transperineal volume from 124 nulliparous asymptomatic women and 118 women with symptoms of pelvic floor dysfunction. Each 3D data set was analyzed by the OmniView‐VCI technique to measure the pelvic hiatal area twice by one operator and once by another to assess intraobserver and interobserver reproducibility. The first operator later measured the hiatal area using the 3D rendering method to evaluate intermethod agreement. Reproducibility and intermethod agreement were studied by the intraclass correlation coefficient and Bland‐Altman method.ResultsHiatal area measurements by the OmniView‐VCI technique showed high intraobserver and interobserver reproducibility in both asymptomatic and symptomatic women. In addition, high agreement was shown between the new technique and 3D rendering in both groups. No systematic differences were noted in any of the reliability studies performed. The new technique took slightly less time to calculate the hiatal area than the standard rendering method in both asymptomatic and symptomatic women.ConclusionsOmniView‐VCI is a reliable method for pelvic hiatal area measurement. Further studies are needed to assess its reliability under contraction and the Valsalva maneuver and to evaluate its usefulness and reproducibility for diagnosis of levator ani lesions.
Electrostatic solitary waves with distinct speeds associated with asymmetric reconnection
Authors: Graham D. B. , Khotyaintsev Yu. V. , Vaivads A. , André M. 
Published: December 2014

AbstractElectrostatic solitary waves (ESWs) are observed at the magnetopause with distinct time scales. These ESWs are associated with asymmetric reconnection of the cold dense magnetosheath plasma with the hot tenuous magnetospheric plasma. The distinct time scales are shown to be due to ESWs moving at distinct speeds and having distinct length scales. The length scales are of order 5–50 Debye lengths, and the speeds range from ∼50 km s−1 to ∼1000 km s−1. The ESWs are observed near the reconnection separatrices. The observation of ESWs with distinct speeds suggests that multiple instabilities are occurring. The implications for reconnection at the magnetopause are discussed.
Magnetic reconnection at Neptune's magnetopause
Authors: Masters A. 
Published: December 2014

AbstractWhat we know about the magnetosphere of the outermost planet, Neptune, is primarily based on data taken during the Voyager 2 flyby in 1989. Establishing how Neptune's magnetosphere interacts with the solar wind is crucial for understanding the dynamics of the system. Here we assess how magnetic reconnection couples the solar wind to Neptune's magnetosphere, using analytical modeling that was recently applied to the case of Uranus. The modeling suggests that typical near‐Neptune solar wind parameters make conditions at Neptune's magnetopause less favorable for magnetic reconnection than at the magnetopause boundary of any other solar system magnetosphere. The location of reconnection sites on Neptune's magnetopause is expected to be highly sensitive to planetary longitude and season, as well as interplanetary magnetic field (IMF) orientation, which is similar to the situation at Uranus. Also similar to past Uranus results, the present Neptune modeling indicates a seasonal effect, where one of the two dominant (Parker spiral) IMF orientations produces more favorable conditions for magnetopause reconnection than the other near equinox. We estimate the upper limit of the reconnection voltage applied to Neptune's magnetosphere as 35 kV (the typical voltage is expected to be considerably lower). Further progress in understanding the solar wind‐magnetosphere interaction at Neptune requires other coupling mechanisms to be considered, as well as how reconnection operates at high plasma β.
Winter bloom and associated upwelling northwest of the Luzon Island: A coupled physical‐biological modeling approach
Authors: Lu Wenfang , Yan Xiao‐Hai , Jiang Yuwu 
Published: December 2014

AbstractFor this paper, a coupled physical‐biological model was developed in order to study the mechanisms of the winter bloom in the Luzon Strait (referred as LZB). Based on a simulation for January 2010, the results showed that the model was capable of reproducing the key features of the LZB, such as the location, inverted‐V shape, twin‐core structure and bloom intensity. The simulation showed that the LZB occurred during the relaxation period of intensified northeasterly winds, when the deepened mixed layer started to shoal. Nutrient diagnostics showed that vertical mixing was responsible for the nutrient supply to the upper ∼40 m layer, while subsurface upwelling supplied nutrients to the region below the mixed layer. Hydrodynamic diagnostics showed that the advection of relative vorticity (RV) primarily contributed to the subsurface upwelling. The RV advection was resulted from an offshore jet, which was associated with a northeasterly wind, flowed across the ambient RV field.
A new algorithm to retrieve chromophoric dissolved organic matter (CDOM) absorption spectra in the UV from ocean color
Authors: Cao Fang , Miller William L. 
Published: December 2014

AbstractAccurate estimation of the absorption coefficient (ag) for chromophoric dissolved organic matter (CDOM) over ultraviolet (UV) and short visible radiation wavelengths (with λ = 275–450 nm) is crucial to provide a robust assessment of the biogeochemical significance of UV in the global ocean. Using a training data set spanning a variety of water types from the clearest open ocean to dynamic inshore waters, a novel algorithm to accurately resolve CDOM absorption spectra from ocean color is presented. Employing a suite of multivariate statistical approaches (principal component analysis, cluster analysis, and multiple linear regression), this new algorithm was developed with matched field data for CDOM spectra and remote sensing reflectance (Rrs) at Sea‐viewing Wide Field‐of‐view Sensor (SeaWiFS) bands. Freed from any presupposition about CDOM spectral shape or conventional spectral extrapolations from visible data, our algorithm allows direct retrieval of a fully resolved CDOM absorption spectrum over UV wavelengths from visible Rrs and further enables a global scale view of the dynamics of CDOM over different water types. Accuracy of ag retrieval is good, with a mean absolute percent difference for ag in the UV of ∼25%. With fully resolved spectra, maps of calculated CDOM spectral slopes (S275–295, S350–400) and slope ratios (SR) are presented with the potential to provide new information about the chemical composition (e.g., molecular weight and aromaticity), sources, transformation, and cycling pathways of CDOM on global as well as regional scales. The new algorithm will contribute to improved accuracy for photochemical and photobiological rate calculations from ocean color.
Drivers of inorganic carbon dynamics in first‐year sea ice: A model study
Authors: Moreau Sébastien , Vancoppenolle Martin , Delille Bruno , Tison Jean‐Louis , Zhou Jiayun , Kotovitch Marie , Thomas David N. , Geilfus Nicolas‐Xavier , Goosse Hugues 
Published: December 2014

AbstractSea ice is an active source or a sink for carbon dioxide (CO2), although to what extent is not clear. Here, we analyze CO2 dynamics within sea ice using a one‐dimensional halothermodynamic sea ice model including gas physics and carbon biogeochemistry. The ice‐ocean fluxes, and vertical transport, of total dissolved inorganic carbon (DIC) and total alkalinity (TA) are represented using fluid transport equations. Carbonate chemistry, the consumption, and release of CO2 by primary production and respiration, the precipitation and dissolution of ikaite (CaCO3·6H2O) and ice‐air CO2 fluxes, are also included. The model is evaluated using observations from a 6 month field study at Point Barrow, Alaska, and an ice‐tank experiment. At Barrow, results show that the DIC budget is mainly driven by physical processes, wheras brine‐air CO2 fluxes, ikaite formation, and net primary production, are secondary factors. In terms of ice‐atmosphere CO2 exchanges, sea ice is a net CO2 source and sink in winter and summer, respectively. The formulation of the ice‐atmosphere CO2 flux impacts the simulated near‐surface CO2 partial pressure (pCO2), but not the DIC budget. Because the simulated ice‐atmosphere CO2 fluxes are limited by DIC stocks, and therefore <2 mmol m−2 d−1, we argue that the observed much larger CO2 fluxes from eddy covariance retrievals cannot be explained by a sea ice direct source and must involve other processes or other sources of CO2. Finally, the simulations suggest that near‐surface TA/DIC ratios of ∼2, sometimes used as an indicator of calcification, would rather suggest outgassing.
Decadal variations in trace metal concentrations on a coral reef: Evidence from a 159 year record of Mn, Cu, and V in a Porites coral from the northern South China Sea
Authors: Chen Xuefei , Wei Gangjian , Deng Wenfeng , Liu Ying , Sun Yali , Zeng Ti , Xie Luhua 
Published: December 2014

AbstractGeochemical cycles of trace metals are important influences on the composition and function of the marine ecosystem. Although spatial distributions of most trace metals have now been determined in at least some parts of the oceans, temporal variations have barely been studied on account of data limitations. In this paper, we report on a 159 year record of trace metal concentrations from a Porites coral from the northern South China Sea (SCS), and discuss how oceanic and climatic processes control variations in Mn, Cu, and V concentrations in this region. Our results show that trace metal concentrations in the coral skeleton demonstrate decadal to interdecadal fluctuations, and that their variations are controlled by different mechanisms. The input of Mn to reef water is partly controlled by the Pacific Decadal Oscillation (PDO), which controls precipitation and river runoff. Surface water concentrations of the nutrient‐like element Cu are controlled by summer upwelling to the east of Hainan Island. The concentrations of V show complex interrelationships, and are linked to riverine input prior to the 1990 and to upwelling after the 1990. Our results imply that in the northern SCS, ocean‐atmosphere climate fluctuations, such as the PDO and the East Asian Summer Monsoon (EASM), are important factors that influence long‐term variability of Mn, Cu, and V concentrations in seawater, by controlling precipitation‐related river runoff and the strength of upwelling systems.
Stratospheric dynamics and midlatitude jets under geoengineering with space mirrors and sulfate and titania aerosols
Authors: Ferraro A. J. , Charlton‐Perez A. J. , Highwood E. J. 
Published: December 2014

AbstractThe impact on the dynamics of the stratosphere of three approaches to geoengineering by solar radiation management is investigated using idealized simulations of a global climate model. The approaches are geoengineering with sulfate aerosols, titania aerosols, and reduction in total solar irradiance (representing mirrors placed in space). If it were possible to use stratospheric aerosols to counterbalance the surface warming produced by a quadrupling of atmospheric carbon dioxide concentrations, tropical lower stratospheric radiative heating would drive a thermal wind response which would intensify the stratospheric polar vortices. In the Northern Hemisphere this intensification results in strong dynamical cooling of the polar stratosphere. Northern Hemisphere stratospheric sudden warming events become rare (one and two in 65 years for sulfate and titania, respectively). The intensification of the polar vortices results in a poleward shift of the tropospheric midlatitude jets in winter. The aerosol radiative heating enhances the tropical upwelling in the lower stratosphere, influencing the strength of the Brewer‐Dobson circulation. In contrast, solar dimming does not produce heating of the tropical lower stratosphere, and so there is little intensification of the polar vortex and no enhanced tropical upwelling. The dynamical response to titania aerosol is qualitatively similar to the response to sulfate.
Evidence for explosive silicic volcanism on the Moon from the extended distribution of thorium near the Compton‐Belkovich Volcanic Complex
Authors: Wilson J. T. , Eke V. R. , Massey R. J. , Elphic R. C. , Jolliff B. L. , Lawrence D. J. , Llewellin E. W. , McElwaine J. N. , Teodoro L. F. A. 
Published: December 2014

AbstractWe reconstruct the abundance of thorium near the Compton‐Belkovich Volcanic Complex on the Moon, using data from the Lunar Prospector Gamma Ray Spectrometer. We enhance the resolution via a pixon image reconstruction technique and find that the thorium is distributed over a larger (40km × 75 km) area than the (25km × 35 km) high‐albedo region normally associated with Compton‐Belkovich. Our reconstructions show that inside this region, the thorium concentration is 14–26ppm. We also find additional thorium, spread up to 300km eastward of the complex at ∼2 ppm. The thorium must have been deposited during the formation of the volcanic complex, because subsequent lateral transport mechanisms, such as small impacts, are unable to move sufficient material. The morphology of the feature is consistent with pyroclastic dispersal, and we conclude that the present distribution of thorium was likely created by the explosive eruption of silicic magma.
Enhancing Electrochemical Water‐Splitting Kinetics by Polarization‐Driven Formation of Near‐Surface Iron(0): An In Situ XPS Study on Perovskite‐Type Electrodes
Authors: Opitz Alexander K. , Nenning Andreas , Rameshan Christoph , Rameshan Raffael , Blume Raoul , Hävecker Michael , Knop‐Gericke Axel , Rupprechter Günther , Fleig Jürgen , Klötzer Bernhard 
Published: December 2014

AbstractIn the search for optimized cathode materials for high‐temperature electrolysis, mixed conducting oxides are highly promising candidates. This study deals with fundamentally novel insights into the relation between surface chemistry and electrocatalytic activity of lanthanum ferrite based electrolysis cathodes. For this means, near‐ambient‐pressure X‐ray photoelectron spectroscopy (NAP‐XPS) and impedance spectroscopy experiments were performed simultaneously on electrochemically polarized La0.6Sr0.4FeO3−δ (LSF) thin film electrodes. Under cathodic polarization the formation of Fe0 on the LSF surface could be observed, which was accompanied by a strong improvement of the electrochemical water splitting activity of the electrodes. This correlation suggests a fundamentally different water splitting mechanism in presence of the metallic iron species and may open novel paths in the search for electrodes with increased water splitting activity.
Nonisothermal crystallization and morphology of crystallites of polyamide 66 and copolyamide 66 containing 2‐carboxyethyl phenyl phosphinic acid
Authors: Tan Sheng Long , Ma Lian Xin , Sun Xiao Guang , Tang Xu Dong 
Published: December 2014

ABSTRACTFlame‐retardant polyamide 66 with a 10% mass fraction of 2‐carboxyethyl phenyl phosphinic acid (CEPPA) hexamethylene diamine salt (PA66‐10) was fabricated in our previous study. In this study, the nonisothermal crystallization kinetics of pure polyamide 66 (PA66‐0) and PA66‐10 were measured by differential scanning calorimetry, and the data obtained were analyzed, and we calculated the average Avrami exponent (n) and used the Jeziorny, Mo, and Kissinger methods. The results from all of these methods show that the crystallization mechanism of PA66‐0 mainly consisted of three stages, whereas PA66‐10 mainly consisted of two stages. At the prime stage, both PA66‐0 and PA66‐10 may have had the same crystallization mechanism. When the cooling rates were 15 and 20°C/min, the approximate n suggested that the growth form of the spherulite mode in PA66‐0 may have been complicated, whereas PA66‐10 may have had a one‐dimensional, two‐dimensional space‐extension, circular, diffusion controlled growth. The crystallization activation energies were determined to be 183.2 and 301 kJ/mol for PA66‐0 and PA66‐10, respectively, by the Kissinger method. To further study the influence of the addition of CEPPA on the crystallization behaviors of PA66‐0, the spherulitic morphologies were examined by polarized light microscopy. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41790.
Effect of additives on the melt rheology and thermal degradation of poly[(R)‐3‐hydroxybutyric acid]
Authors: Arza Carlos R. , Jannasch Patric , Johansson Peter , Magnusson Per , Werker Alan , Maurer Frans H. J. 
Published: December 2014

ABSTRACTThermal degradation of poly[(R)−3‐hydroxybutyric acid] (PHB) during melt mixing results in random chain scission that produces shorter polymer chains containing crotonic and carboxyl end groups. One way of preventing this serious reduction of molar mass is to add agents that react with at least two of the newly generated end groups. Different types of commercially available additives known to react with carboxyl group, namely bis(3,4‐epoxycyclohexylmethyl) adipate (BECMA), 2,2'‐bis(2‐oxazoline) (BOX), trimethylolpropane tris(2‐methyl‐1‐aziridinepropionate) (PETAP), triphenyl phosphate (TPP), tris(nonylphenyl) phosphate (TNPP), polycarbodiimide (PCDI), and poly(methyl metharylate‐co‐glycidyl methacrylate) (GMA.MMA) were mixed with PHB by cocasting from solution in chloroform. Dynamic rheology as well as measurements of molar masses before and after dynamic analysis was used to evaluate the effect of the additives on the melt stability of PHB. Measurements of the dynamic shear modulus and the molar mass of molten PHB with the additives PCDI and GMA.MMA showed a minor improvement on the thermal stability. Furthermore, TPP and TNPP did not affect the thermal stability of PHB, whereas the presence of BECMA, BOX, and PETAP gave a strong decrease of the dynamic modulus compared with neat PHB. © 2014 The Authors Journal of Applied Polymer Science Published by Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41836.