bluuebunny/crossref_metadata_2025 huggingface dataset:
Putative Immunogenicity Expression Profiling Using Human Pluripotent Stem Cells and Derivatives
Authors: Awe Jason P. , Gschweng Eric H. , Vega-Crespo Agustin , Voutila Jon , Williamson Mary H. , Truong Brian , Kohn Donald B. , Kasahara Noriyuki , Byrne James A.
Published: January 2015

Autologous human induced pluripotent stem cells (hiPSCs) should allow cellular therapeutics without an associated immune response. This concept has been controversial since the original report that syngeneic mouse iPSCs elicited an immune response after transplantation. However, an investigative analysis of any potential acute immune responses in hiPSCs and their derivatives has yet to be conducted. In the present study, we used correlative gene expression analysis of two putative mouse “immunogenicity” genes, ZG16 and HORMAD1, to assay their human homologous expression levels in human pluripotent stem cells and their derivatives. We found that ZG16 expression is heterogeneous across multiple human embryonic stem cell and hiPSC-derived cell types. Additionally, ectopic expression of ZG16 in antigen-presenting cells is insufficient to trigger a detectable response in a peripheral blood mononuclear cell coculture assay. Neither of the previous immunogenicity-associated genes in the mouse currently appears to be relevant in a human context.
Predicting subgrid variability of soil water content from basic soil information
Authors: Qu W. , Bogena H. R. , Huisman J. A. , Vanderborght J. , Schuh M. , Priesack E. , Vereecken H.
Published: January 2015

Knowledge of unresolved soil water content variability within model grid cells (i.e., subgrid variability) is important for accurate predictions of land‐surface energy and hydrologic fluxes. Here we derived a closed‐form expression to describe how soil water content variability depends on mean soil water content (σθ(<θ>)) using stochastic analysis of 1‐D unsaturated gravitational flow based on the van Genuchten‐Mualem (VGM) model. A sensitivity analysis showed that the n parameter strongly influenced both the shape and magnitude of the maximum of σθ(<θ>). The closed‐form expression was used to predict σθ(<θ>) for eight data sets with varying soil texture using VGM parameters obtained from pedotransfer functions that rely on available soil information. Generally, there was good agreement between observed and predicted σθ(<θ>) despite the obvious simplifications that were used to derive the closed‐form expression. Furthermore, the novel closed‐form expression was successfully used to inversely estimate the variability of hydraulic properties from observed σθ(<θ>) data.
Shock‐induced prompt relativistic electron acceleration in the inner magnetosphere
Authors: Foster J. C. , Wygant J. R. , Hudson M. K. , Boyd A. J. , Baker D. N. , Erickson P. J. , Spence H. E.
Published: January 2015

We present twin Van Allen Probes spacecraft observations of the effects of a solar wind shock impacting the magnetosphere on 8 October 2013. The event provides details both of the accelerating electric fields associated with the shock and the response of inner magnetosphere electron populations across a broad range of energies. During this period, the two Van Allen Probes observed shock effects from the vantage point of the dayside magnetosphere at radial positions of L = 3 and L = 5, at the location where shock‐induced acceleration of relativistic electrons occurs. The extended (~1 min) duration of the accelerating electric field across a broad extent of the dayside magnetosphere, coupled with energy‐dependent relativistic electron gradient drift velocities, selects a preferred range of energies (3–4 MeV) for the initial enhancement. Those electrons—whose drift velocity closely matches the azimuthal phase velocity of the shock‐induced pulse—stayed in the accelerating wave as it propagated tailward and received the largest increase in energy. Drift resonance with subsequent strong ULF waves further accentuated this range of electron energies. Phase space density and positional considerations permit the identification of the source population of the energized electrons. Observations detail the promptness (<20 min), energy range (1.5–4.5 MeV), energy increase (~500 keV), and spatial extent (L* ~3.5–4.0) of the enhancement of the relativistic electrons. Prompt acceleration by impulsive shock‐induced electric fields and subsequent ULF wave processes therefore comprises a significant mechanism for the acceleration of highly relativistic electrons deep inside the outer radiation belt as shown clearly by this event.
A possible mechanism for the formation of filamentous structures in magnetoplasmas by kinetic Alfvén waves
Authors: Chen L. , Wu D. J. , Zhao G. Q. , Tang J. F. , Huang J.
Published: January 2015

Due to having strong anisotropy in their polarization state and spatial structure, it is believed that kinetic Alfvén waves (KAWs) can play an important role in various energization phenomena of plasma particles and the fine‐structure formation in magnetoplasma environments. The filamentous fine structures are a kind of the common density inhomogeneity phenomena in magnetoplasmas, and hence, the density gradient is one of the sources of free energy that can lead to KAWs instabilities. In this paper, based on the two‐fluid model in which ions and electrons are treated as separate fluids, we investigate the effect of density gradient inhomogeneous on the dispersion and instability of KAWs in a magnetoplasma. The results show that KAW instability can be excited effectively by the density gradient. Especially, both the real frequency ωR and the growth rate ωI of KAWs are dramatically dependent on the spatial position x in the presence of an inhomogeneous density gradient. The results also show that the real frequency increases with the characteristic spatial scale of inhomogeneity , while the growth rate of KAWs has a maximum in the growing ranges of . On the other hand, the excited KAWs are weakly dispersive with λekx<1. The results have potential importance for a better understanding of the microphysics of the filamentous fine‐structure formation since the phenomena of density gradient inhomogeneous are ubiquitous in various magnetoplasmas, such as in the laboratory plasma as well as in both the solar coronal and terrestrial auroral plasmas.
Electron densities inferred from plasma wave spectra obtained by the Waves instrument on Van Allen Probes
Authors: Kurth W. S. , De Pascuale S. , Faden J. B. , Kletzing C. A. , Hospodarsky G. B. , Thaller S. , Wygant J. R.
Published: January 2015

The twin Van Allen Probe spacecraft, launched in August 2012, carry identical scientific payloads. The Electric and Magnetic Field Instrument Suite and Integrated Science suite includes a plasma wave instrument (Waves) that measures three magnetic and three electric components of plasma waves in the frequency range of 10 Hz to 12 kHz using triaxial search coils and the Electric Fields and Waves triaxial electric field sensors. The Waves instrument also measures a single electric field component of waves in the frequency range of 10 to 500 kHz. A primary objective of the higher‐frequency measurements is the determination of the electron density ne at the spacecraft, primarily inferred from the upper hybrid resonance frequency fuh. Considerable work has gone into developing a process and tools for identifying and digitizing the upper hybrid resonance frequency in order to infer the electron density as an essential parameter for interpreting not only the plasma wave data from the mission but also as input to various magnetospheric models. Good progress has been made in developing algorithms to identify fuh and create a data set of electron densities. However, it is often difficult to interpret the plasma wave spectra during active times to identify fuh and accurately determine ne. In some cases, there is no clear signature of the upper hybrid band, and the low‐frequency cutoff of the continuum radiation is used. We describe the expected accuracy of ne and issues in the interpretation of the electrostatic wave spectrum.
Measurements of the changing wave velocities of sand during the formation and dissociation of disseminated methane hydrate
Authors: Sultaniya A. K. , Priest J. A. , Clayton C. R. I.
Published: January 2015

The formation and dissociation of methane hydrate within sediment can lead to large changes in wave velocities, which provide valuable insights into the processes involved in hydrate formation. These are of practical importance in geophysical characterization, as well as developing strategies for the future exploitation of methane hydrates. This paper presents changes in wave velocity, measured during hydrate formation, and subsequent dissociation, using the resonant column apparatus. Hydrate was formed under “drained” and “undrained” conditions. Drained specimens had free access to methane during formation, while for undrained specimens, methane content was fixed. Hydrate formation and dissociation were induced by changing the specimen temperature under constant effective stress. In excess of 20 determinations of shear wave and flexural wave velocity were carried out over a 9 h period, both during hydrate formation and dissociation. This time was sufficient to record almost all of the changes in wave velocity within a specimen. The exothermic nature of hydrate formation was clearly seen in the form of spikes in temperature measured at the base of the specimens. For all specimens, the relationship between wave velocity and degree of hydrate saturation was nonlinear and significantly different during formation and dissociation. The patterns observed suggest that hydrate morphology not only is important in controlling the ultimate wave velocities, at the end of formation, but has a significant impact on the rates of change of wave velocities during formation and dissociation. A conceptual model is presented to explain differences in observed behavior during formation and dissociation.
Reassessing the 2006 Guerrero slow‐slip event, Mexico: Implications for large earthquakes in the Guerrero Gap
Authors: Bekaert D. P. S. , Hooper A. , Wright T. J.
Published: January 2015

In Guerrero, Mexico, slow‐slip events have been observed in a seismic gap, where no earthquakes have occurred since 1911. A rupture of the entire gap today could result in aMw8.2–8.4 earthquake. However, it remains unclear how slow‐slip events change the stress field in the Guerrero seismic region and what their implications are for devastating earthquakes. Most earlier studies have relied on a sparse network of Global Navigation Satellite Systems measurements. Here we show that interferometric synthetic aperture radar can be used to improve the spatial resolution. We find that slip due to the 2006 slow‐slip event enters the seismogenic zone and the Guerrero Gap, with ∼5 cm slip reaching depths as shallow as 12 km. We show that slow slip is correlated with a highly coupled region and estimate that slow‐slip events have decreased the total accumulated moment since the end of the 2001/2002 slow‐slip event (4.7 years) by ∼50%. Nevertheless, even accounting for slow slip, the moment deficit in the Guerrero Gap increases each year byMw∼6.8. The Guerrero Gap therefore still has the potential for a large earthquake, with a slip deficit equivalent toMw∼8.15 accumulated over the last century. Correlation between the slow‐slip region and nonvolcanic tremor, and between slow slip and an ultraslow velocity layer, supports the hypothesis of a common source potentially related to high pore pressures.
A spatially variable power law tropospheric correction technique for InSAR data
Authors: Bekaert D. P. S. , Hooper A. , Wright T. J.
Published: January 2015

Microwave signals traveling through the troposphere are subject to delays. These delays are mainly described by spatial and temporal variations in pressure, temperature, and relative humidity in the lower part of the troposphere, resulting in a spatially varying tropospheric signal in interferometric synthetic aperture radar (InSAR). Tropospheric correction techniques rely either on external data, often limited by spatial and temporal accuracy or can be estimated from the high‐resolution interferometric phase itself. However, current phase‐estimated correction techniques do not account for the spatial variability of the tropospheric properties and fail to capture tropospheric signals over larger regions. Here we propose and test a novel power law correction method that accounts for spatial variability in atmospheric properties and can be applied to interferograms containing topographically correlated deformation. The power law model has its reference fixed at the relative top of the troposphere and describes, through a power law relationship, how the phase delay varies with altitude. We find the power law model reduces tropospheric signals both locally (on average by ∼0.45 cm for each kilometer of elevation in Mexico) and the long‐wavelength components, leading to an improved fit to independent Global Navigation Satellite Systems data. The power law model can be applied in presence of deformation, over a range of different time periods and in different atmospheric conditions, and thus permits the detection of smaller‐magnitude crustal deformation signals with InSAR.
Absolute gravity change associated with magma mass movement in the conduit of Asama Volcano (Central Japan), revealed by physical modeling of hydrological gravity disturbances
Authors: Kazama Takahito , Okubo Shuhei , Sugano Takayuki , Matsumoto Shigeo , Sun Wenke , Tanaka Yoshiyuki , Koyama Etsuro
Published: January 2015

The gravity signal originating from magma mass movement in a volcanic conduit is retrieved from the hydrologically disturbed absolute gravity data obtained at Asama Volcano (Central Japan) in 2004, using a three‐dimensional hydrological model. We improve the hydrological model of the previous study using realistic soil parameters and boundary conditions, to better estimate the spatiotemporal land‐water distributions and the consequent hydrological gravity disturbances. The newly estimated gravity disturbances agree with the absolute gravity values observed by FG5 gravimeters in 2004–2009 within about 2.6 μGal, by additionally accounting for the excess discharge of groundwater mass associated with a sloping impermeable surface below the discharge area. After the gravity disturbance of 20 μGal amplitude is subtracted from the absolute gravity data observed during the 2004 eruptive event, the gravity residual of 5 μGal amplitude shows a significant decrease in synchronization with eruptions, because the ascending magma mass in the conduit affects the upward attraction force to the gravimeters installed on the flank of Asama Volcano. The magma head altitude, to which the residual gravity is converted assuming a homogeneous linear density in the conduit, shows a comprehensive agreement of the time variation in the magma head with those in other volcanic observations, such as gas emission rate and earthquake frequency. By correcting the hydrological gravity disturbances using this hydrological model and simultaneously obtained meteorological data in real time, spatiotemporal variations in the magma mass can be instantaneously monitored at Asama Volcano, even before eruptions during future volcanic events.
Analysis of riverine suspended particulate matter fluxes (Gulf of Lion, Mediterranean Sea) using a synergy of ocean color observations with a 3‐D hydrodynamic sediment transport model
Authors: Le Fouest Vincent , Chami Malik , Verney Romaric
Published: January 2015

The export of riverine suspended particulate matter (SPM) in the coastal ocean has major implications for the biogeochemical cycles. In the Mediterranean Sea (France), the Rhone River inputs of SPM into the Gulf of Lion (GoL) are highly variable in time, which severely impedes the assessment of SPM fluxes. The objectives of this study are (i) to investigate the prediction of the land‐to‐ocean flux of SPM using the complementarity (i.e., synergy) between a hydrodynamic sediment transport model and satellite observations, and (ii) to analyze the spatial distribution of the SPM export. An original approach that combines the MARS‐3D model with satellite ocean color data is proposed. Satellite‐derived SPM and light penetration depth are used to initialize MARS‐3D and to validate its predictions. A sensitivity analysis is performed to quantify the impact of riverine SPM size composition and settling rate on the horizontal export of SPM. The best agreement between the model and the satellite in terms of SPM spatial distribution and export is obtained for two conditions: (i) when the relative proportion of “heavy and fast” settling particles significantly increases relative to the “light and slow” ones, and (ii) when the settling rate of heavy and light SPM increases by fivefold. The synergy between MARS‐3D and the satellite data improved the SPM flux predictions by 48% near the Rhone River mouth. Our results corroborate the importance of implementing satellite observations within initialization procedures of ocean models since data assimilation techniques may fail for river floods showing strong seasonal variability.
Landfast ice affects the stability of the Arctic halocline: Evidence from a numerical model
Authors: Itkin Polona , Losch Martin , Gerdes Rüdiger
Published: January 2015

Landfast ice covers large surface areas of the winter Siberian Seas. The immobile landfast ice cover inhibits divergent and convergent motion, hence dynamical sea ice growth and redistribution, decouples winter river plumes in coastal seas from the atmosphere, and positions polynyas at the landfast ice edge offshore. In spite of the potentially large effects, state‐of‐the‐art numerical models usually do not represent landfast ice in its correct extent. A simple parametrization of landfast ice based on bathymetry and internal sea ice strength is introduced and its effects on the simulated Arctic Ocean are demonstrated. The simulations suggest that the Siberian landfast ice impacts the Arctic halocline stability through enhanced brine production in polynyas located closer to the shelf break and by redirecting river water to the Canadian Basin. These processes strengthen the halocline in the Canadian Basin, but erode its stability in the Makarov and Eurasian Basins.
Calculation of beams of positrons, neutrons, and protons associated with terrestrial gamma ray flashes
Authors: Köhn Christoph , Ebert Ute
Published: January 2015

Positron beams have been observed by the Fermi satellite to be correlated with lightning leaders, and neutron emissions have been attributed to lightning and to laboratory sparks as well. Here we discuss the cross sections to be used for modeling these emissions, and we calculate the emissions of positrons, neutrons, and also protons from lightning leaders. Neutrons were first erroneously attributed to fusion reactions, but the photonuclear reaction responsible for neutrons should create protons as well. We predict them here; they have not been observed yet. In the paper, we first revisit the model for stepped lightning leaders of Xu, Celestin, and Pasko with updated cross sections, we analyze the spatial and energetic structure of the electron beam, and we calculate the spectrum of the generated gamma ray beam at 16 km altitude. Then we review the scattering processes of photons with emphasis on the processes above 5 MeV, in particular the photon energy losses in Compton scattering events and the generation of leptons and hadrons. We provide simple approximations for photon energy loss and lepton and hadron production for any photon with energy above 5 MeV passing through an arbitrary air layer. Finally, we launch a gamma ray beam with the earlier calculated spectrum of the negative stepped lightning leader from 16 km upward and calculate the production and energy of positrons, neutrons, and protons as well as the propagation of positrons.
Multiscale decomposition for heterogeneous land‐atmosphere systems
Authors: Liu Shaofeng , Shao Yaping , Hintz Michael , Lennartz‐Sassinek Sabine
Published: January 2015

The land‐atmosphere system is characterized by pronounced land surface heterogeneity and vigorous atmospheric turbulence both covering a wide range of scales. The multiscale surface heterogeneities and multiscale turbulent eddies interact nonlinearly with each other. Understanding these multiscale processes quantitatively is essential to the subgrid parameterizations for weather and climate models. In this paper, we propose a method for surface heterogeneity quantification and turbulence structure identification. The first part of the method is an orthogonal transform in the probability density function (PDF) domain, in contrast to the orthogonal wavelet transforms which are performed in the physical space. As the basis of the whole method, the orthogonal PDF transform (OPT) is used to asymptotically reconstruct the original signals by representing the signal values with multilevel approximations. The “patch” idea is then applied to these reconstructed fields in order to recognize areas at the land surface or in turbulent flows that are of the same characteristics. A patch here is a connected area with the same approximation. For each recognized patch, a length scale is then defined to build the energy spectrum. The OPT and related energy spectrum analysis, as a whole referred to as the orthogonal PDF decomposition (OPD), is applied to two‐dimensional heterogeneous land surfaces and atmospheric turbulence fields for test. The results show that compared to the wavelet transforms, the OPD can reconstruct the original signal more effectively, and accordingly, its energy spectrum represents the signal's multiscale variation more accurately. The method we propose in this paper is of general nature and therefore can be of interest for problems of multiscale process description in other geophysical disciplines.
Constructing accurate maps of atmospheric water vapor by combining interferometric synthetic aperture radar and GNSS observations
Authors: Alshawaf Fadwa , Hinz Stefan , Mayer Michael , Meyer Franz J.
Published: January 2015

Over the past 20years, repeat‐pass spaceborne interferometric synthetic aperture radar (InSAR) has been widely used as a geodetic technique to generate maps of the Earth's topography and to measure the Earth's surface deformation. In this paper, we present a new approach to exploit microwave data from InSAR, particularly Persistent Scatterer InSAR (PSI), and Global Navigation Satellite Systems (GNSS) to derive maps of the absolute water vapor content in the Earth's atmosphere. Atmospheric water vapor results in a phase shift in the InSAR interferogram, which if successfully separated from other phase components provides valuable information about its distribution. PSI produces precipitable water vapor (PWV) difference maps of a high spatial density, which can be inverted using the least squares method to retrieve PWV maps at each SAR acquisition time. These maps do not contain the absolute (total) PWV along the signal path but only a part of it. The components eliminated by forming interferograms or phase filtering during PSI data processing are reconstructed using GNSS phase observations. The approach is applied to build maps of absolute PWV by combining data from InSAR and GNSS over the region of Upper Rhine Graben in Germany and France. For validation, we compared the derived PWV maps with PWV maps measured by the optical sensor MEdium‐Resolution Imaging Spectrometer. The results show strong spatial correlation with values of uncertainty of less than 1.5mm. Continuous grids of PWV are then produced by applying the kriging geostatistical interpolation technique that exploits the spatial correlations between the PWV observations.
A snowfall detection algorithm over land utilizing high‐frequency passive microwave measurements—Application to ATMS
Authors: Kongoli Cezar , Meng Huan , Dong Jun , Ferraro Ralph
Published: January 2015

This paper presents a snowfall detection algorithm over land from high‐frequency passive microwave measurements. The algorithm computes the probability of snowfall using logistic regression and the principal components of the seven high‐frequency brightness temperature measurements at Atmospheric Technology Microwave Sounder (ATMS) channel frequencies 89 GHz and above. The oxygen absorption channel 6 (53.6 GHz) is utilized as temperature proxy to define the snowfall retrieval domain. Ground truth surface meteorological data including snowfall occurrence were collected over Conterminous U.S. and Alaska during two winter seasons in 2012–2013 and 2013–2014. Statistical analysis of the in situ data matched with ATMS measurements showed that in relatively warmer weather, snowfall tends to be associated with lower high‐frequency brightness temperatures than no snowfall, and the brightness temperatures are negatively correlated with measured snowfall rate. In colder weather conditions, however, snowfall tends to occur at higher microwave brightness temperatures than no‐snowfall, and the brightness temperatures are positively correlated with snowfall rate. The brightness temperature decrease and the negative correlations with snowfall rate in warmer weather are attributed to the scattering effect. It is hypothesized that the scattering effect is insignificant in colder weather due to the predominance of lighter snowfall and emission. Based on these results, a two‐step algorithm is developed that optimizes snowfall detection over these two distinct temperature regimes. Evaluation of the algorithm shows skill in capturing snowfall in variable weather conditions as well as the remaining challenges in the retrieval of lighter and colder snowfall.
Lunar Surface Gravimeter as a lunar seismometer: Investigation of a new source of seismic information on the Moon
Authors: Kawamura Taichi , Kobayashi Naoki , Tanaka Satoshi , Lognonné Philippe
Published: January 2015

Lunar seismology has always suffered from the limited number of seismic stations and limited coverage of the seismic network. Additional seismic data are necessary to probe the lunar interior in depth. Instead of a costly new deployment of seismometers, the aim of this study is to investigate the possibility of using the Apollo 17 Lunar Surface Gravimeter (LSG) as a lunar seismometer. The LSG was designed to detect gravitational waves (associated to change in the curvature of spacetime) and tidal ground motion on the Moon, but the data were not investigated for seismic use partially because of a malfunction of the instrument. We first evaluated the influence of the malfunction through comparison with other Apollo seismic data and found that the effect of the malfunction is small, and the LSG detected seismic signals in a manner that was consistent with those of the other Apollo seismometers. Then we carried out source location with the additional station of the LSG. We relocated previously located deep moonquake nests to evaluate the influence of the LSG data, which are generally noisier than other Apollo seismic data. Then we located deep moonquake nests that were previously unlocatable. Forty deep moonquake nests were examined, and we located five new nests. One newly located nest, A284, was most likely to be located on the farside. This series of analyses indicates that the LSG functioned as a lunar seismometer, and that its data are useful for improving seismic analyses with the previous seismic data set of the Moon.
The influence of crustal strength fields on the patterns and rates of fluvial incision
Authors: Roy S. G. , Koons P. O. , Upton P. , Tucker G. E.
Published: January 2015

Gradients in the bedrock strength field are increasingly recognized as integral to the rates and patterns of landscape evolution. To explore this influence, we incorporate data from fault strength profiles into a landscape evolution model, under the assumption that erodibility of rock is proportional to the inverse square root of cohesion for bedrock rivers incised by bedload abrasion. Our model calculations illustrate how patterns in the crustal strength field can play a dominant role in local fluvial erosion rates and consequently the development of fluvial network patterns. Fluvial incision within weak zones can be orders of magnitude faster than that for resistant bedrock. The large difference in erosion rate leads to the formation of a straight, high‐order channel with short, orthogonal tributaries of low order. In comparison, channels incising into homogeneous strength fields produce dendritic drainage patterns with no directional dependence associated with erodibility gradients. Channels that cross the strength gradient experience local variations in knickpoint migration rate and the development of stationary knickpoints. Structurally confined channels can shift laterally if they incise into weak zones with a shallow dip angle, and this effect is strongly dependent on the magnitude of the strength difference, the dip angle, and the symmetry and thickness of the weak zone. The influence of the strength field on drainage network patterns becomes less apparent for erodibility gradients that approach homogeneity. There are multiple natural examples with drainage network patterns similar to those seen in our numerical experiments.
Complex inner core of the Earth: The last frontier of global seismology
Authors: Tkalčić Hrvoje
Published: January 2015

The days when the Earth's inner core (IC) was viewed as a homogeneous solid sphere surrounded by the liquid outer core (OC) are now behind us. Due to a limited number of data sampling the IC and a lack of experimentally controlled conditions in the deep Earth studies, it has been difficult to scrutinize competitive hypotheses in this active area of research. However, a number of new concepts linking IC structure and dynamics has been proposed lately to explain different types of seismological observations. A common denominator of recent observational work on the IC is increased complexity seen in IC physical properties such as its isotropic and anisotropic structure, attenuation, inner core boundary (ICB) topography, and its rotational dynamics. For example, small‐scale features have been observed to exist as a widespread phenomenon in the uppermost inner core, probably superimposed on much longer‐scale features. The characterization of small‐scale features sheds light on the nature of the solidification process and helps in understanding seismologically observed hemispherical dichotomy of the IC. The existence of variations in the rate and level of solidification is a plausible physical outcome in an environment where vigorous compositional convection in the OC and variations in heat exchange across the ICB may control the process of crystal growth. However, further progress is hindered by the fact that the current traveltime data of PKIKP waves traversing the IC do not allow discriminating between variations in isotropic P wave velocity and velocity anisotropy. Future studies of attenuation in the IC might provide crucial information about IC structure, although another trade‐off exists—that of the relative contribution of scattering versus viscoelastic attenuation and the connection with the material properties. Future installations of dense arrays, cross paths of waves that sample the IC, and corresponding array studies will be a powerful tool to image and clearly distinguish between viscoelastic and scattering attenuation, and isotropic‐ and anisotropic‐heterogeneity related effects on traveltimes of core‐sensitive body waves. This will then inevitably contribute to a better understanding of what the IC is made of, how it solidifies and how it contributes to the generation and dynamics of the geomagnetic field.
The UCSD kinematic IPS solar wind boundary and its use in the ENLIL 3‐D MHD prediction model
Authors: Jackson B. V. , Odstrcil D. , Yu H.‐S. , Hick P. P. , Buffington A. , Mejia‐Ambriz J. C. , Kim J. , Hong S. , Kim Y. , Han J. , Tokumaru M.
Published: January 2015

The University of California, San Diego interplanetary scintillation (IPS) time‐dependent kinematic 3‐D reconstruction technique has been used and expanded upon for over a decade to provide predictions of heliospheric solar wind parameters. These parameters include global reconstructions of velocity, density, and (through potential field modeling and extrapolation upward from the solar surface) radial and tangential interplanetary magnetic fields. Time‐dependent results can be extracted at any solar distance within the reconstructed volume and are now being exploited as inner boundary values to drive the ENLIL 3‐D MHD model in near real time. The advantage of this coupled system is that it uses the more complete physics of 3‐D MHD modeling to provide an automatic prediction of coronal mass ejections and solar wind stream structures several days prior to their arrival at Earth without employing coronagraph observations. Here we explore, with several examples, the current differences between the IPS real‐time kinematic analyses and those from the ENLIL 3‐D MHD modeling using IPS‐derived real‐time boundaries. Future possibilities for this system include incorporating many different worldwide IPS stations as input to the remote sensing analysis using ENLIL as a kernel in the iterative 3‐D reconstructions.
Natural‐Based Nanocomposites for Bone Tissue Engineering and Regenerative Medicine: A Review
Authors: Pina Sandra , Oliveira Joaquim M. , Reis Rui L.
Published: January 2015

Tissue engineering and regenerative medicine has been providing exciting technologies for the development of functional substitutes aimed to repair and regenerate damaged tissues and organs. Inspired by the hierarchical nature of bone, nanostructured biomaterials are gaining a singular attention for tissue engineering, owing their ability to promote cell adhesion and proliferation, and hence new bone growth, compared with conventional microsized materials. Of particular interest are nanocomposites involving biopolymeric matrices and bioactive nanosized fillers. Biodegradability, high mechanical strength, and osteointegration and formation of ligamentous tissue are properties required for such materials. Biopolymers are advantageous due to their similarities with extracellular matrices, specific degradation rates, and good biological performance. By its turn, calcium phosphates possess favorable osteoconductivity, resorbability, and biocompatibility. Herein, an overview on the available natural polymer/calcium phosphate nanocomposite materials, their design, and properties is presented. Scaffolds, hydrogels, and fibers as biomimetic strategies for tissue engineering, and processing methodologies are described. The specific biological properties of the nanocomposites, as well as their interaction with cells, including the use of bioactive molecules, are highlighted. Nanocomposites in vivo studies using animal models are also reviewed and discussed.
Hodgkin transformation of chronic lymphocytic leukemia: Incidence, outcomes, and comparison to de novoHodgkin lymphoma
Authors: Parikh Sameer A. , Habermann Thomas M. , Chaffee Kari G. , Call Timothy G. , Ding Wei , Leis Jose F. , Macon William R. , Schwager Susan M. , Ristow Kay M. , Porrata Luis F. , Kay Neil E. , Slager Susan L. , Shanafelt Tait D.
Published: January 2015

Although transformation to Hodgkin lymphoma (HL) is a recognized complication in patients with chronic lymphocytic leukemia (CLL), its incidence, clinical characteristics and outcomes are not well defined. We used the Mayo Clinic CLL and Lymphoma Databases to identify CLL patients who developed biopsy‐proven HL (CLL/HL) on follow‐up, as well as cases of de novo HL (i.e., without prior CLL). Among 3887 CLL patients seen at Mayo Clinic from January 1995 through August 2011, 26 (0.7%) developed HL. In a nested cohort of 2,465 newly diagnosed CLL patients followed prospectively, the incidence of HL was 0.05%/year (10 year risk = 0.5%). The median overall survival (OS) from date of HL diagnosis in patients with CLL/HL was 3.9 years compared to not reached for de novo HL patients (n = 709) seen during the same time interval (P < 0.001). The shorter OS of CLL/HL patients persisted after adjusting for differences in age and Ann Arbor stage of disease. The International Prognostic score (IPS) developed for de novo HL stratified prognosis among CLL/HL patients with median survival of not reached, 6.2, 2.4, and 0.3 years (P = 0.006) for those with IPS scores of ≤2, 3, 4, and ≥5, respectively. In summary, approximately 1 of every 200 CLL patients will develop HL within 10 years. Survival after HL diagnosis in patients with CLL is shorter than de novo HL patients. The IPS for de novo HL may be useful for stratifying survival in CLL/HL patients. Am. J. Hematol. 90:334–338, 2015. © 2015 Wiley Periodicals, Inc.
Diffusion slowdown in the nanostructured liquid Ga‐Sn alloy
Authors: Podorozhkin Dmitri Y. , Charnaya Elena V. , Lee Min Kai , Chang Lieh‐Jeng , Haase Juergen , Michel Dieter , Kumzerov Yurii A. , Fokin Alexsandr V.
Published: January 2015

The diffusion of gallium in liquid Ga‐Sn alloy embedded into different porous silica matrices was studied by NMR. Spin relaxation was measured for two gallium isotopes, 71Ga and 69Ga, at two magnetic fields. Pronounced rise of quadrupole contribution to relaxation was observed for the nanostructured alloy which increased with decreasing the pore size. The correlation time of atomic mobility was evaluated and found to be much larger than in the relevant bulk melt which evidenced a pronounced diffusion slowdown in the Ga‐Sn alloy under nanoconfinement. It is shown that the diffusion was slower by a factor of 30 for the alloy within 7 nm pores. The spectral densities of electric field gradients at zero frequency were found to double for the finest pores. The Knight shift was found to decrease but slightly for the nanostructured alloy.
Bifunctional cellulose derivatives for the removal of heavy‐metal ions and phenols: Synthesis and adsorption studies
Authors: Wu Ronglan , Tian Lingyuan , Wang Wei , Man Xiaolin
Published: January 2015

In this article, we report a study of the design and synthesis of a bifunctional cellulose derivative on the removal of phenols and heavy‐metal ions in wastewater treatment. A radical polymerization was performed in an ionic liquid, 1‐allyl‐3‐methylimidazolium chloride, to graft two monomers, butyl methacrylate and 4‐vinyl pyridine, on the backbone of cellulose. The effects of the five reaction conditions on the yield of final products were evaluated. The grafted celluloses were characterized by means of Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. Adsorption experiments were carried out on the cellulose‐g‐poly(butyl methacrylate‐co‐4‐vinyl pyridine) to evaluate the capacity of the removal of 2,4‐dichlorophenol (2,4‐DCP) and Cu(II) in water. The adsorption isotherms were measured at five temperatures and interpreted by a Langmuir model of adsorption. The thermodynamics of the adsorption suggested that the binding process was mildly exothermic for Cu(II) and endothermic for 2,4‐DCP. Kinetic studies were interpreted with a pseudo‐second‐order adsorption model. The process of the adsorption of 2,4‐DCP could be described overall by the model, whereas the adsorption of Cu(II) involved two processes. This was due to adsorption both on the surface and inside the adsorbent. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41830.
Fabrication of hierarchical wrinkled morphologies through sequential UVO treatments
Authors: Rodríguez‐Hernández Juan , del Campo Adolfo
Published: January 2015

The fabrication, in a controlled manner, of well‐defined micrometer size topographical features on polymer surfaces is a great challenge due to the large variety of potential applications of these materials ranging from adhesion, optics to responsive interfaces. A challenging issue concerns the fabrication of interfaces having surface moieties with sizes at different length scales. Herein we describe the fabrication of hierarchical wrinkled surfaces involving two sequential ultraviolet‐ozone (UVO) treatments. This methodology allowed us to tailor the shape of PDMS surfaces and create a large variety of different patterns expected to have a broad range of applications requiring surface features with variable sizes. More interestingly, the employment of UVO treatments to produce surfaces with up to three distinct levels of order since they enable the rigidification of the interface by formation of a SiOx layer or the degradation of the PDMS surface when longer treatments. The surfaces prepared by using this approach presented patterns three different scales: the structure provided by the mask employed, the wrinkled surface inside of the directly exposed areas (related to the hole size of the mask) and the wrinkled surface protected during the first treatment by the mask (which is related to the mesh dimensions of the mask employed). © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41863.
Statistical inference on transit route‐level origin–destination flows using automatic passenger counter data
Authors: Ji Yuxiong , You Qiyuan , Jiang Shengchuan , Zhang Hongjun Michael
Published: January 2015

We consider inferring transit route‐level origin–destination (OD) flows using large amounts of automatic passenger counter (APC) boarding and alighting data based on a statistical formulation. One critical problem is that we need to enumerate the OD flow matrices that are consistent with the APC data for each bus trip to evaluate the model likelihood function. The OD enumeration problem has not been addressed satisfactorily in the literature. Thus, we propose a novel sampler to avoid the need to enumerate OD flow matrices by generating them recursively from the first alighting stop to the last stop of the bus route of interest. A Markov chain Monte Carlo (MCMC) method that incorporates the proposed sampler is developed to simulate the posterior distributions of the OD flows. Numerical investigations on an operational bus route under a realistic OD structure demonstrate the superiority of the proposed MCMC method over an existing MCMC method and a state‐of‐the‐practice method. Copyright © 2015 John Wiley & Sons, Ltd.
Percutaneous extraction of inadvertently placed left‐sided pacemaker leads with complete cerebral embolic protection
Authors: Bahadorani John N. , Schricker Amir A. , Pretorius Victor G. , Birgersdotter‐Green Ulrika , Dominguez Arturo , Mahmud Ehtisham
Published: January 2015

Lead wire malposition is a known, but rare complication of permanent pacemaker or defibrillator implantation. The actual incidence and prevalence is unknown and management options for inadvertent left ventricular lead malposition have not been uniform. Current recommendations include systemic anticoagulation with warfarin or surgical lead removal with circulatory arrest for compelling clinical scenarios. Percutaneous left‐sided lead extraction is contraindicated due to the potentially increased risk of thromboembolic complications associated with this procedure. To our knowledge, this is the first report of percutaneous extraction of inadvertently placed left ventricular and left atrial endocardial pacemaker leads with flow‐preserving complete cerebral embolic protection. We also review the current literature regarding the incidence, management, and percutaneous extraction of left‐sided cardiac leads. © 2015 Wiley Periodicals, Inc.
Propensity‐matched comparison between Direct Flow Medical, Medtronic Corevalve, and Edwards Sapien XT prostheses: Device success, thirty‐day safety, and mortality
Authors: Zhang Yuan , Pyxaras Stylianos A. , Wolf Alexander , Schmitz Thomas , Naber Christoph K.
Published: January 2015

Aims

To compare 30‐day performance of three different type of transcatheter aortic valve implantation (TAVI) prosthesis: Direct Flow Medical (DFM), Medtronic Corevalve (MCV), and Edwards Sapien XT (ES). Methods and Results: Forty consecutive patients treated with DFM for severe aortic stenosis were matched to an equal sample of patients undergoing TAVI with MCV and ES (1:1:1 propensity score‐matching). Primary end‐point was 30‐day safety, defined according to the valve academic research consortium (VARC‐2) criteria. Secondary end‐points were: (i) immediate post‐TAVI transaortic gradient reduction, (ii) device success, and (iii) 30‐day mortality. Patients treated with DFM had higher 30‐day safety rate compared to MCV and ES (respectively: 95.0% vs. 67.5% vs. 82.5%; P = 0.006). Immediate post‐TAVI, transaortic gradient reduction was similar for DFM, MCV, and ES subgroups (respectively: 8.3 ± 5.2 mm Hg vs. 5.3 ± 3.7 mm Hg vs. 5.6 ± 5.1 mm Hg; P = 0.15); likewise, device success did not differ significantly (respectively: 100% vs. 92.5% vs. 92.5%; P = 0.19). Mortality rates were also similar (respectively: 0% vs. 7.5% vs. 7.5%; P = 0.190). In the pooled binary logistic regression analysis, blood transfusion was associated to 30‐day safety (HR 0.156, 95% CI 0.049–0.500, P = 0.002), while a significant trend was observed for the vascular closure device type (favoring Proglide vs. Prostar: HR 0.239, 95% CI 0.049–1.160, P = 0.076). Conclusions: In high‐risk patients with aortic stenosis undergoing TAVI, device success and short‐term mortality were comparable between DFM, MCV, and ES. In contrast, the 30‐day VARC‐defined safety primary end‐point was met significantly more frequently in patients treated with DFM. This result was mainly driven by differences in major vascular complications, associated to differences in vascular closure devices between the different valve subgroups. © 2015 Wiley Periodicals, Inc.
A true bifurcational stenosis treated with a bioresorbable vascular scaffold and a drug‐eluting metallic stent: Degradable meets durable
Authors: Wiebe Jens , Hamm Christian , Nef Holger
Published: January 2015

The role of bioresorbable scaffolds (BRS) has mostly been investigated in simple coronary lesions. True bifurcational stenoses are one of the major challenges in interventional cardiology. We report here a successful case of a hybrid approach using a bioresorbable scaffold and a drug‐eluting metallic stent to treat a true bifurcational lesion. Due to the degradable character of the BRS, only one metallic stent remains and thus the risk of restenosis can possibly be reduced. © 2015 Wiley Periodicals, Inc.
Theoretical and Experimental Studies on Acetylene Absorption in a Polytetrafluoroethylene Hollow‐Fiber Membrane Contactor
Authors: Wang Xiaoxu , Gao Jia , Zhang Jianshu , Zhang Xiaopeng , Guo Ruili
Published: January 2015

The separation of acetylene from a gas mixture was investigated using a polytetrafluoroethylene hollow‐fiber membrane contactor and 1‐methyl‐2‐pyrrolidinone as absorbent. The effects of the gas velocity, the liquid velocity, the feed gas concentration, and the module length on the acetylene mass transfer were investigated. The results showed that the acetylene mass transfer flux increased with increasing liquid velocity, gas velocity, and feed gas concentration, but decreased with increasing membrane module length. A mathematical model was used to predict the wetting extent of the membrane and the mass transfer resistance in the acetylene mass transfer process. The wetting extent of the membrane was found to increase with increasing liquid velocity and to be effectively restrained with increasing gas velocity. The liquid phase resistance and the wetted‐membrane phase resistance controlled the acetylene mass transfer in the acetylene absorption process. The acetylene absorption efficiency was maintained at 90 % for 114 h of the C2H2 membrane absorption–thermal desorption cycle process.