bluuebunny/crossref_metadata_2025 huggingface dataset:
Absolute plate velocities from seismic anisotropy: Importance of correlated errors
Authors: Zheng Lin , Gordon Richard G. , Kreemer Corné
Published: August 2014

The errors in plate motion azimuths inferred from shear wave splitting beneath any one tectonic plate are shown to be correlated with the errors of other azimuths from the same plate. To account for these correlations, we adopt a two‐tier analysis: First, find the pole of rotation and confidence limits for each plate individually. Second, solve for the best fit to these poles while constraining relative plate angular velocities to consistency with the MORVEL relative plate angular velocities. Our preferred set of angular velocities, SKS‐MORVEL, is determined from the poles from eight plates weighted proportionally to the root‐mean‐square velocity of each plate. SKS‐MORVEL indicates that eight plates (Amur, Antarctica, Caribbean, Eurasia, Lwandle, Somalia, Sundaland, and Yangtze) have angular velocities that differ insignificantly from zero. The net rotation of the lithosphere is 0.25 ± 0.11° Ma−1 (95% confidence limits) right handed about 57.1°S, 68.6°E. The within‐plate dispersion of seismic anisotropy for oceanic lithosphere (σ = 19.2°) differs insignificantly from that for continental lithosphere (σ = 21.6°). The between‐plate dispersion, however, is significantly smaller for oceanic lithosphere (σ = 7.4°) than for continental lithosphere (σ = 14.7°). Two of the slowest‐moving plates, Antarctica (vRMS = 4 mm a−1, σ = 29°) and Eurasia (vRMS = 3 mm a−1, σ = 33°), have two of the largest within‐plate dispersions, which may indicate that a plate must move faster than ≈ 5 mm a−1 to result in seismic anisotropy useful for estimating plate motion. The tendency of observed azimuths on the Arabia plate to be counterclockwise of plate motion may provide information about the direction and amplitude of superposed asthenospheric flow or about anisotropy in the lithospheric mantle.
A mechanistic model linking insect (Hydropsychidae) silk nets to incipient sediment motion in gravel‐bedded streams
Authors: Albertson Lindsey K. , Sklar Leonard S. , Pontau Patricia , Dow Michelle , Cardinale Bradley J.
Published: August 2014

Plants and animals affect stream morphodynamics across a range of scales, yet including biological traits of organisms in geomorphic process models remains a fundamental challenge. For example, laboratory experiments have shown that silk nets built by caddisfly larvae (Trichoptera: Hydropsychidae) can increase the shear stress required to initiate bed motion by more than a factor of 2. The contributions of specific biological traits are not well understood, however. Here we develop a theoretical model for the effects of insect nets on the threshold of sediment motion, τ*crit, that accounts for the mechanical properties, geometry, and vertical distribution of insect silk, as well as interactions between insect species. To parameterize the model, we measure the tensile strength, diameter, and number of silk threads in nets built by two common species of caddisfly, Arctopsyche californica and Ceratopsyche oslari. We compare model predictions with new measurements of τ*crit in experiments where we varied grain size and caddisfly species composition. The model is consistent with experimental results for single species, which show that the increase in τ*crit above the abiotic control peaks at 40–70% for 10–22 mm sediments and declines with increasing grain size. For the polyculture experiments, however, the model underpredicts the measured increase in τ*crit when two caddisfly species are present in sediments of larger grain sizes. Overall, the model helps explain why the presence of caddisfly silk can substantially increase the forces needed to initiate sediment motion in gravel‐bedded streams and also illustrates the challenge of parameterizing the behavior of multiple interacting species in a physical model.
Removal of systematic seasonal atmospheric signal from interferometric synthetic aperture radar ground deformation time series
Authors: Samsonov Sergey V. , Trishchenko Alexander P. , Tiampo Kristy , González Pablo J. , Zhang Yu , Fernández José
Published: August 2014

Applying the Multidimensional Small Baseline Subset interferometric synthetic aperture radar algorithm to about 1500 Envisat and RADARSAT‐2 interferograms spanning 2003–2013, we computed time series of ground deformation over Naples Bay Area in Italy. Two active volcanoes, Vesuvius and Campi Flegrei, are located in this area in close proximity to the densely populated city of Naples. For the first time, and with remarkable clarity, we observed decade‐long elevation‐dependent seasonal oscillations of the vertical displacement component with a peak‐to‐peak amplitude of up to 3.0 cm, substantially larger than the long‐term deformation rate (<0.6 cm/yr). Analysis, utilizing surface weather and radiosonde data, linked observed oscillations with seasonal fluctuations of water vapor, air pressure, and temperature in the lower troposphere. The modeled correction is in a good agreement with observed results. The mean, absolute, and RMS differences are 0.014 cm, 0.073 cm, and 0.087 cm, respectively. Atmospherically corrected time series confirmed continuing subsidence at Vesuvius previously observed by geodetic techniques.
Peak tornado activity is occurring earlier in the heart of “Tornado Alley”
Authors: Long John A. , Stoy Paul C.
Published: August 2014

Tornado frequency may increase as the factors that contribute to severe convection are altered by a changing climate. Attributing changes in tornado frequency to observed global climate change is complicated because observational effort has increased over time, but studies of the seasonal distribution of tornado activity may avoid sampling biases. We demonstrate that peak tornado activity has shifted 7 days earlier in the year over the past six decades in the central and southern US Great Plains, the area with the highest global incidence of tornado activity. Results are largely unrelated to large‐scale climate oscillations, and observed climate trends cannot fully account for observations, which suggest that changes to regional climate dynamics should be further investigated. Tornado preparedness efforts at individual to national levels should be cognizant of the trend toward earlier peak tornado activity across the heart of “Tornado Alley”.
Improving the vertical electron density profile in ionospheric imaging at storm time: A case study on 25–27 September 2011
Authors: Yin Ping , Mitchell Cathryn N.
Published: August 2014

Ionospheric responses to geomagnetic storms are important because they can seriously affect radio propagation up to several GHz in frequency, resulting in deterioration of the system performance. There is a key difficulty in the representation of the vertical electron density profile during storms because many tomographic imaging techniques rely on statistical estimations of the profile, which are inadequate in extreme events. The approach here is to use radio occultation observations from Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) to provide this missing information. The method is evaluated over Europe and the United States for a major storm on 25–27 September 2011. The use of COSMIC profiles in GPS tomography does help to improve the vertical imaging accuracy of inversions during storm periods when compared to ionosonde and incoherent scatter radar observations. It is interesting to note that COSMIC vertical profiles are also able to facilitate better representation of the E layer. More availability of density profiles from COSMIC or other similar radio occultation satellites would be greatly welcomed in the future.
RCM‐E and AMIE studies of the Harang reversal formation during a steady magnetospheric convection event
Authors: Yang Jian , Toffoletto Frank , Lu Gang , Wiltberger Michael
Published: August 2014

This paper presents the results of a modeling study on the formation of the Harang reversal (HR) during a steady magnetospheric convection event. The Harang reversal is identified as the boundary of the northward and southward electric field in the nightside auroral zone using the Assimilative Mapping of Ionospheric Electrodynamics (AMIE) procedure. We simulate the event with the Rice Convection Model‐Equilibrium (RCM‐E) by adjusting its boundary conditions to approximately match Time History of Events and Macroscale Interactions during Substorms (THEMIS) and GOES observations in the nightside magnetosphere. Our results show that the HR is collocated with an upward region 1 field‐aligned current, where converging ionospheric currents cause a southward/northward electric field on the poleward/equatorward side of the HR. Our results also indicate that the electric field reversal is slightly poleward of the ionospheric east–west current reversal and is to the northeast of the ground magnetic reversal, which is consistent with previous observations. We also test the sensitivity of the HR formation to a variety of parameters in the RCM‐E simulations. We find that (1) the reduction of the flux tube entropy parameter PV5/3 near the midnight sector plays a major role in the formation of the HR; (2) a run carried out assuming uniform conductance produced the same major features as the run with more realistic precipitation‐enhanced conductance; and (3) the detailed pattern of the polar cap potential distribution plays a minor role, but its dawn‐dusk asymmetry significantly controls the location of the HR with respect to midnight. The RCM‐E simulations also predict PV5/3 and flow distributions associated with the magnetospheric source of the HR in the plasma sheet, which can be further tested against observations.
Large winds and wind shears caused by the nonlinear interactions between gravity waves and tidal backgrounds in the mesosphere and lower thermosphere
Authors: Liu Xiao , Xu Jiyao , Yue Jia , Liu Han Li , Yuan Wei
Published: August 2014

A two‐dimensional nonlinear numerical model was used to simulate large winds (≥ 100 m s−1) and wind shears (≥ 40 m s−1 km−1) in the mesosphere and lower thermosphere (MLT) that are caused by the interaction between gravity waves (GWs) and migrating tidal background. By varying the wavelengths of GWs and the phases of diurnal and semidiurnal tides, 64 numerical experiments were performed. Our numerical experiments indicate that both migrating diurnal and semidiurnal tides strongly modulate the occurrence of GW breaking, and the resulted large winds and wind shears. The simulated large winds and wind shears are in good agreement with those from the rocket‐sounding chemical release measurements. Moreover, the occurrence of large wind shears highly depends on the phases of migrating tides in local time, which is in agreement with the reported lidar observations. The local time dependence of large wind shears is mainly attributed to the filtering and/or hindering effects of diurnal and semidiurnal tidal winds on GWs. Our simulation reveals that the nonlinear interactions between GWs breaking and the migrating diurnal and semidiurnal tides may play an important role in driving the large winds and wind shears in the MLT region and their local time dependence.
Reaction‐driven fracturing of porous rock
Authors: Ulven O. I. , Jamtveit B. , Malthe‐Sørenssen A.
Published: August 2014

A 2‐D computer model has been developed to investigate fluid‐mediated transformation processes such as chemical weathering, mineral carbonation, and serpentinization that require transport of H2O and/or CO2 into reacting rock volumes. Hydration and carbonation cause local volume expansion, and the resulting nonuniform stresses may drive fracturing, which increases both the rate of transport and the accessible reactive surface area in the system and thus accelerates the rate of the transformation process. The model couples reactions, fracturing, and fluid transport for systems with a range of initial porosities, assumed constant throughout the process. With low initial porosity, a sharp reaction front between completely reacted material and unreacted material propagates into unaltered rock, while for high porosities, diffuse reaction fronts are formed in which a large fraction of the initial volume is partly reacted. When diffusive transport is rate limiting, the total reaction rate depends on porosity to a power N, where N is in the range 0.45–2. The exponent N increases as the reaction‐generated expansion decreases. In high‐porosity rocks, the total reaction rate is limited by reaction kinetics, and it is thus insensitive to porosity variations. As the volume increasing reaction proceeds, fracturing divides the unreacted porous material into subdomains, which may undergo further subdivision as they are consumed by the reaction. The total reaction rate and progress depend on the initial geometry of a reacting domain, and this significantly affects the weathering profiles for systems that evolve from an initial assembly of blocks with different sizes and shapes.
Failure mechanisms in coal: Dependence on strain rate and microstructure
Authors: Zhao Yixin , Liu Shimin , Zhao Gao‐Feng , Elsworth Derek , Jiang Yaodong , Han Jingli
Published: August 2014

The brittle coal failure behavior under various axial strain rates from 10−3 to 10−2 s−1 is experimentally and numerically studied. The numerical microscale finite difference model is built on the accurate X‐ray microcomputed tomography images, which provides a ground‐breaking and bottom‐up approach to investigate the effects of microstructure on coal failure under various strain rates. Experimentally, prior to loading, the coal sample is scanned, and the three‐dimensional coal structure model is constructed. The microheterogeneous structures are incorporated in the model, which facilitates the deformation and failure mechanism analysis under different loading conditions. The results reveal that the microheterogeneous structures significantly affect the evolution of stress concentrations and deformation behaviors in the sample. The coal tends to fail in the shear mode before the peak strength, since the shear zone is created with high displacements. However, tensile failure ultimately controls the failure process after the peak strength. Notably, the strain rate dependence of coal strength is observed, and an empirical relationship is proposed to describe the dynamic strength of the coal under various loading strain rates. Importantly, the coal strengthens with an increase in strain rate. For brittle material, such as coal, the strength and failure mechanism are strain rate and microstructure dependent. The strain rate‐dependent coal strength index (n) is found to be a dynamic parameter in the range of strain rate from 10−3 to 10−2 s−1, and this finding may extend the concept of strain rate dependence over a broader range of loading conditions.
Assessing a dry surface layer‐based soil resistance parameterization for the Community Land Model using GRACE and FLUXNET‐MTE data
Authors: Swenson S. C. , Lawrence D. M.
Published: August 2014

The Community Land Model (CLM) exhibits biases in evapotranspiration (ET) and total water storage (TWS) in semiarid regions. The TWS seasonal cycle amplitude is too low, while evapotranspiration is too strong and variable. These biases are consistent with excessive soil evaporation when the canopy is sparse or absent, which reduces moisture inputs into the ground. Here we improve the simulation of soil evaporation by replacing CLM's existing empirical soil resistance parameterization with a more mechanistically based formulation in which soil evaporation is controlled by the rate of diffusion of water vapor through a dry surface layer (DSL). The thickness of the DSL is parameterized as a soil‐type dependent function of top layer soil moisture. Soil resistances are calculated from the DSL thickness combined with a soil tortuosity factor. Compared to the existing CLM soil resistance parameterization, the DSL‐based soil resistances for a given soil moisture value are generally larger, especially for moister soils. CLM simulations using the DSL‐based soil resistance expression have reduced biases of ET relative to the FLUXNET‐MTE (Model Tree Ensemble) data set and TWS relative to Gravity Recovery and Climate Experiment (GRACE) observations. Averaged over global semiarid regions, the CLM mean annual amplitude of TWS increases from 26.3 mm to 32.5 mm when the new soil resistance parameterization is used, in good agreement with the GRACE mean annual amplitude for these regions of 32.2 ±2.1 mm. CLM mean annual ET, averaged over global semiarid regions, decreases from 27.8 mm/month to 23.5 mm/month, closer to the FLUXNET‐MTE mean annual ET of 21.1 ± 0.9 mm/month. The seasonal amplitude of CLM ET also decreases, from 23.3 mm/month to 18.3 mm/month compared to 14.9 ± 1.1 mm/month for FLUXNET‐MTE.
Interaction among alluvial cover, bed roughness, and incision rate in purely bedrock and alluvial‐bedrock channel
Authors: Inoue Takuya , Izumi Norihiro , Shimizu Yasuyuki , Parker Gary
Published: August 2014

A major control on bedrock incision is the interaction between alluvial cover and erosive mobile grains. The extent of alluvial cover is typically predicted as a function of relative sediment flux (sediment supply rate over bed load transport capacity, qbs/qbc), yet little is known about how the bed roughness affects the alluvial cover. We performed field experiments with various flow discharges, sediment supply rates, grain sizes, and bed surface topographies. We then developed physically based models for estimating the threshold of sediment movement and the extent of alluvial cover, so as to include the effect of roughness change. The results for the threshold of sediment movement and the extent of alluvial cover obtained from our models show reasonable agreement with the results of the field experiments. We explored the sensitivity of the models to variations in sediment supply and bedrock relative roughness (bedrock hydraulic roughness height over grain size, ksb/d). The results suggest the following: (1) a larger relative roughness yields a greater dimensionless critical shear stress required for initial sediment motion; (2) at a given sediment supply rate, the extent of alluvial cover is larger when the relative roughness is larger; (3) when the sediment supply rate and the relative roughness are small, throughput bed load moves over (and can abrade) a purely bedrock channel with no alluvial cover; and (4) the critical value of sediment supply rate below which throughput bed load transport occurs increases with decreasing relative roughness. The experimental results and analysis provide a framework for treating the (a) incisional morphodynamics of purely bedrock rivers by throughput bed load with no alluvial cover, (b) incisional/alluvial morphodynamics of mixed bedrock‐alluvial rivers, and (c) purely alluvial morphodynamics, as well as the transition between these states.
Evaluation of slope stability with respect to snowpack spatial variability
Authors: Gaume J. , Schweizer J. , van Herwijnen A. , Chambon G. , Reuter B. , Eckert N. , Naaim M.
Published: August 2014

The evaluation of avalanche release conditions constitutes a great challenge for risk assessment in mountainous areas. The spatial variability of snowpack properties has an important impact on snow slope stability and thus on avalanche formation, since it strongly influences failure initiation and crack propagation in weak snow layers. Hence, the determination of the link between these spatial variations and slope stability is very important, in particular, for avalanche public forecasting. In this study, a statistical‐mechanical model of the slab‐weak layer (WL) system relying on stochastic finite element simulations is used to investigate snowpack stability and avalanche release probability for spontaneously releasing avalanches. This model accounts, in particular, for the spatial variations of WL shear strength and stress redistribution by elasticity of the slab. We show how avalanche release probability can be computed from release depth distributions, which allows us to study the influence of WL spatial variations and slab properties on slope stability. The importance of smoothing effects by slab elasticity is verified and the crucial impact of spatial variation characteristics on the so‐called knock‐down effect on slope stability is revisited using this model. Finally, critical length values are computed from the simulations as a function of the various model parameters and are compared to field data obtained with propagation saw tests.
Molecular mechanism underlying the impact of vitamin D on disease activity of MS
Authors: Munger Kassandra L. , Köchert Karl , Simon Kelly C. , Kappos Ludwig , Polman Chris H. , Freedman Mark S. , Hartung Hans P. , Miller David H. , Montalbán Xavier , Edan Gilles , Barkhof Frederik , Pleimes Dirk , Sandbrink Rupert , Ascherio Alberto , Pohl Christoph
Published: August 2014

Objective

Some previous studies suggest modest to strong effects of 25‐hydroxyvitamin D (25(OH)D) on multiple sclerosis (MS) activity. The objective of this study was to explore the mechanistic rationale that may explain potential clinical effects of 25(OH)D.

Methods

This study measured serum 25(OH)D levels and global gene expression profiles over a course of up to 2 years in patients starting treatment with interferon beta‐1b (IFNB‐1b) after a clinically isolated syndrome.MSdisease activity was assessed by the number of gadolinium‐enhancing lesions present on repeated magnetic resonance imaging (MRIs).

Results

The number of gadolinium‐enhancing lesions was highly significantly associated with 25(OH)D levels. Conducting various systems‐level analyses on the molecular level, multiple lines of evidence indicated that 25(OH)D regulates expression dynamics of a large gene–gene interaction system which primarily regulates immune modulatory processes modulatingMSactivity. The vitamin D response element was significantly enriched in this system, indicating a direct regulation of this gene interaction network through the vitamin D receptor. With increasing 25(OH)D levels, resulting regulation of this system was associated with a decrease inMSactivity. Within the complex network of genes that are regulated by 25(OH)D, well‐described targets ofIFNB‐1b and a regulator of sphingosine‐1‐phosphate bioavailability were found. The 25(OH)D effects onMSactivity were additively enhanced byIFNB‐1b.

Interpretation

Here, we provide mechanistic evidence that an unbalanced 25(OH)D gene expression system may affectMSactivity. Our findings support a potential benefit of monitoring and managing vitamin D levels (e.g., through supplementation) in earlyMSpatients treated withIFN‐beta‐1b.
Cobalt‐Impregnated Magnetite as General Heterogeneous Catalyst for the Hydroacylation Reaction of Azodicarboxylates
Authors: Pérez Juana M. , Ramón Diego J.
Published: August 2014

Catalysts consisting of cobalt and nickel impregnated on magnetite have been prepared, characterized and used for the hydroacylation reaction of different azodicarboxylate compounds with aldehydes, using nearly stoichiometric amounts of both reagents in only 3 h. Furthermore, this reaction has been conducted with the smallest amount of catalyst. The cobalt catalyst is stable enough to be removed by magnetic decantation and recycled ten‐fold without any detrimental effect on the results.

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Manganese(III)‐Catalyzed Oxidative Cyclization of Aryl 1‐Cyanoalk‐5‐ynyl Ketone Systems: A Convenient and General Approach to Cyclopenta[b]naphthalene Derivatives
Authors: Wong Ying‐Chieh , Kao Tzu‐Ting , Huang Jing‐Kai , Jhang Yi‐Wun , Chou Ming‐Chen , Shia Kak‐Shan
Published: August 2014

A convenient and general approach for cyclopenta[b]naphthalene derivatives containing a structurally diverse functionality at C‐4 position has been successfully developed, whereby manganese(III) acetate plays a key role to facilitate the tandem 5‐exo‐dig and 6‐exo/endo cyclization in an efficient manner. Various functional groups, including trimethyl silyl, aryl, ester, ketone, secondary/tertiary amide, phosphonate and halogen, capped on the terminal acetylenic unit are well tolerated under optimal reaction conditions. It is highly conceivable that this novel [6.6.5] framework formation procedure may have broad synthetic utility in light of its operational simplicity and high yields.

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Enantioselective Intramolecular Hydroamination of Unactivated Alkenes Catalyzed by Mono‐ and Bis(gold) Phosphine Complexes
Authors: Lee Seong Du , Timmerman Jacob C. , Widenhoefer Ross A.
Published: August 2014

A 1:2 mixture of (P1)(AuCl)2 [P1=(S)‐DTBM‐MeO‐BIPHEP] and silver tetrafluoroborate (AgBF4) in methanol catalyzes the intramolecular hydroamination of unactivated alkenes with carbamates and ureas to form pyrrolidine derivatives with up to 85% ee.

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Lysosomal pH Rise during Heat Shock Monitored by a Lysosome‐Targeting Near‐Infrared Ratiometric Fluorescent Probe
Authors: Wan Qiongqiong , Chen Suming , Shi Wen , Li Lihong , Ma Huimin
Published: August 2014

Heat stroke is a life‐threatening condition, featuring a high body temperature and malfunction of many organ systems. The relationship between heat shock and lysosomes is poorly understood, mainly because of the lack of a suitable research approach. Herein, by incorporating morpholine into a stable hemicyanine skeleton, we develop a new lysosome‐targeting near‐infrared ratiometric pH probe. In combination with fluorescence imaging, we show for the first time that the lysosomal pH value increases but never decreases during heat shock, which might result from lysosomal membrane permeabilization. We also demonstrate that this lysosomal pH rise is irreversible in living cells. Moreover, the probe is easy to synthesize, and shows superior overall analytical performance as compared to the existing commercial ones. This enhanced performance may enable it to be widely used in more lysosomal models of living cells and in further revealing the mechanisms underlying heat‐related pathology.
A novel foaming approach to prepare porous superabsorbent poly(sodium acrylic acid) resins
Authors: Bao Jianshe , Chen Si , Wu Bozhen , Ma Meng , Shi Yanqin , Wang Xu
Published: August 2014

A system composed of surfactant and foam stabilizer is used in preparing porous superabsorbent resins (SARs) of poly(sodium acrylic acid) (PAA‐Na), which is obtained by free‐radical solution polymerization of partially neutralized acrylic acid with mechanical agitation of eggbeater. Different types of surfactant, including anionic surfactant sodium n‐dodecyl benzene sulfate (SDBS), cationic surfactant cetyltrimethyl ammonium bromide, and nonionic surfactant alkylphenols poly(oxyethylene) (OP‐10), are used as blowing agent to produce pores by mechanical agitation, and triethanolamine (TEA) is used to act as foam stabilizer agent. The results show that a synergistic effect of SDBS with TEA is obtained and the packing density is decreased, which could be proved by the clearly porous morphology, and the water absorbing capacity of SARs is enhanced. As a result, such method can get PAA‐Na SARs without any organic solvents, which provides an environmentally beneficial way to prepare SARs for hygiene and biomedical products. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41298.
Tear force of physically crosslinked poly(vinyl alcohol) gels with different submicrometer‐scale network structures
Authors: Noh Taegu , Bando Yujiro , Ota Kensuke , Sasaki Saori , Suzuki Atsushi
Published: August 2014

Poly(vinyl alcohol) (PVA) gels can be easily prepared by either the freeze‐thawing (FT gel) method or by the cast‐drying (CD gel) method. Although the resulting nanostructured networks of the FT and CD gels are similar, their physical properties are quite different; while CD gels are transparent and elastic, FT gels are opaque and less elastic. Moreover, the tear energy of the FT gels is much greater than that of the CD gels, which is a direct result of micrometer‐scale differences in their network structures. In order to control the distribution of microcrystallites on nano‐ and micrometer scales, FT gels were prepared from PVA solutions with different water contents. As a result, the gel gradually became more transparent as the initial water content was decreased; and accordingly, the tear energy decreased. Tear resistance was improved in the case of FT gels by repeating the number of FT cycles, whereas with CD gels, this was achieved by increasing the gelation temperature. These results indicate that the microscopic network structures are characterized by a micrometer‐scale bundled‐polymer (fibril), which determines the tear energy of FT gels. Simple methods to control the fibril network structure of FT gels using a unidirectional freezing method are presented herein, with the swelling and mechanical properties of modified FT gels discussed in terms of their multiple‐scale network structures. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41356.
Composites based on CB/CF/Ag filled EPDM/NBR rubber blends with high conductivity
Authors: Ding Xuejiao , Wang Jingwen , Zhang Su , Wang Jie , Li Shuqin
Published: August 2014

For many applications of conductive rubbers, it is desirable to endow the conductive rubber with high conductivity at low conductive filler loading. In this work, composites based on ethylene‐propylene‐diene monomer (EPDM) rubber and nitrile‐butadiene rubber (NBR) were prepared using carbon blacks, carbon fibers, and silver powders as fillers. As the weight fraction of silver powder increased, the hardness of composites increased gradually while the tensile strength and elongation at break decreased. SEM revealed that the EPDM/NBR blends exhibited a relatively co‐continuous morphology. The differential scanning calorimetry (DSC) curves reported the EPDM/NBR rubber blends were incompatibility. The thermogravimetry (TG) studies showed that adding a small amount of silver powder could improve the thermal stability of composites. These conductive composites exhibited good electrical property. At room temperature, when the total volume fraction of fillers was 15.20%, the volume resistivity of EPDM/NBR blend was only 0.0058 Ω cm. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41357.
Energy Prices, Subsidies and Resource Tax Reform in China
Authors: Zhang ZhongXiang
Published: August 2014

The Chinese leadership in November 2013 is determined to embark upon a new wave of comprehensive reforms in China. This is clearly reflected by the key decision of the Third Plenum of the 18th Central Committee of Communist Party of China to assign the market a decisive role in allocating resources. To have the market to play that role, getting the energy prices right is crucial. While the overall trend of China's energy pricing reform since 1984 has been moving towards a more market‐oriented pricing mechanism, the pace and scale of the reform differ across energy types. This article discusses the evolution of price reforms for coal, petroleum products, natural gas and electricity in China, provides some analysis of these energy price reforms, and suggests that few areas of reforms could take place in order to have the market play that decisive role and help China's transition to a low‐carbon economy.
International Institutions and the Rise of Asia
Authors: Drysdale Peter , Willis Sébastien
Published: August 2014

This article applies a game‐theoretical analysis of institutions to the international institutional architecture, of which the G20 is treated as a central element. The article argues that international institutions such as the World Trade Organization or the International Monetary Fund are best understood as mechanisms for coordinating and supporting equilibria in repeated games played among policy‐makers in the world's largest economies. The growth of the emerging economies, particularly in Asia, has altered these games, and there is no guarantee, with these new entrants and new issues that have emerged, that the old equilibrium strategies are still viable. The G20, it is argued, is best understood as an attempt to respond to this change and coordinate play on a new set of globally welfare‐enhancing equilibria in these games.
Crows on the Cradles: Palestinian Mothers at a Frontline Vortex Reflections on the Psychology of Occupation
Authors: Roth Judy , Duaibis Salwa
Published: August 2014

Palestinian mothers living in the friction points in East Jerusalem and the West Bank provide critical windows into the traumas that challenge families ensnarled in the vortex of ongoing political violence and living under occupation. Our paper, using interviews of Palestinian mothers, is a view of the abnormal – the violence that infects childhood and parenting, the fight of some mothers for a “real normal”, and the induction into the “new normal”, in which the night‐time incursions, the mapping of communities, the detention of their adolescent sons, the solitary confinements of some, are “accepted” as a rite of passage. Managing terror and its anticipation exhausts and corrodes family functioning and community life. Mothers become inducted into a traumatic vortex, as they struggle to contain the anguish, multiple losses, and the outrage over the dispossession of longings and claims. Our own inescapable countransference, a simultaneous compulsion to understand coupled with an aversion to engage, provided vital information about the stench of violence that permeates these mothers' lives and the terror of losing not only children but one's mind, as well. Copyright © 2014 John Wiley & Sons, Ltd.
Glycine Improves Biochemical and Biomechanical Properties Following Inflammation of the Achilles Tendon
Authors: Vieira Cristiano Pedrozo , Oliveira Letícia Prado De , Guerra Flávia Da Ré , Almeida Marcos Dos Santos De , Marcondes Maria Cristina Cintra Gomes , Pimentel Edson Rosa
Published: August 2014

Tendinopathy of the Achilles tendon is a clinical problem that motivates the scientific community to search for treatments that assist in restoring its functional properties. Glycine has broad biological effects, acting as a modulator of the inflammatory cascade, and is the predominant amino acid in collagen. A 5% glycine diet provided beneficial effects against toxicity and inflammation since glycine may restructure the collagen molecules faster due to its broad anti‐inflammatory effects. The purpose was analyze the effects of a 5% glycine diet in rats as a treatment for the inflammatory process. The experimental groups were as follows: C (control group), G1 and G3 (inflammatory group), and G2 and G4 (glycine + inflammatory group). G1 and G2 were euthanized 8 days following injury, and G3 and G4 were euthanized 22 days following injury. The concentrations of hydroxyproline, non‐collagenous proteins, and glycosaminoglycans, as well as the activity of MMP‐2 and ‐9 were analyzed. Biomechanical and morphological tests were employed. Higher concentrations of hydroxyproline and glycosaminoglycans were found in G4 and an increased activity of MMP‐2 was found in G2. Higher birefringence was noted in group G2. The biomechanical results indicated that the tendon was more resistant to loading to rupture upon treatment with a glycine diet in group G4. Glycine induced the synthesis of important components of the tendon. A rapid remodeling was noted when compared with the inflamed‐only groups. These data suggest that glycine may be a beneficial supplement for individuals with inflammation of the Achilles tendon. Anat Rec, 298:538–545, 2015. © 2014 Wiley Periodicals, Inc.
A Critical Role of the Transcription Factor Fli‐1 in Murine Lupus Development by Regulation of Interleukin‐6 Expression
Authors: Sato Shuzo , Lennard Richard Mara , Brandon Danielle , Jones Buie Joy N. , Oates Jim C. , Gilkeson Gary S. , Zhang Xian K.
Published: August 2014

Objective

The Fli‐1 transcription factor is implicated in the pathogenesis of systemic lupus erythematosus (SLE), both in humans and in animal models. Dysregulation of interleukin‐6 (IL‐6) is also associated with SLE. The purpose of this study was to investigate whether Fli‐1 directly regulates the expression of IL‐6.

Methods

Sera were collected from wild‐type and Fli‐1–heterozygous (Fli‐1+/−) MRL/lpr mice, and the concentration of IL‐6 was measured by enzyme‐linked immunosorbent assay (ELISA). Expression of IL‐6 in the kidney was measured by real‐time polymerase chain reaction analysis. T cells were isolated from wild‐type and Fli‐1+/− MRL/lpr mice and stimulated with CD3/CD28 beads, and the concentration of IL‐6 in the supernatants was measured by ELISA. MS1 endothelial cells were transfected with Fli‐1 and control small interfering RNA, and the production of IL‐6 was compared after lipopolysaccharide stimulation. A chromatin immunoprecipitation (ChIP) assay was performed to determine whether Fli‐1 binds to the IL‐6 promoter region. Transient transfections with the NIH3T3 cell line were performed to examine whether Fli‐1 regulates the expression of IL‐6.

Results

Fli‐1+/− MRL/lpr mice had significantly decreased IL‐6 levels in sera and reduced expression of IL‐6 in kidneys as compared to their wild‐type littermates. T cells isolated from Fli‐1+/− MRL/lpr mice produced less IL‐6 than did those from wild‐type mice. Inhibiting the expression of Fli‐1 in endothelial cells resulted in reduced production of IL‐6. The ChIP assay revealed direct binding of Fli‐1 to 3 regions within the IL‐6 promoter. Fli‐1 activated transcription from the IL‐6 promoter in a dose‐dependent manner.

Conclusion

The direct regulation of IL‐6 expression by Fli‐1 represents one possible mechanism for the protective effect of decreased Fli‐1 expression in lupus.
The Nuclear Receptor Constitutive Androstane Receptor/NR1I3 Enhances the Profibrotic Effects of Transforming Growth Factor β and Contributes to the Development of Experimental Dermal Fibrosis
Authors: Avouac Jérôme , Palumbo‐Zerr Katrin , Ruzehaji Nadira , Tomcik Michal , Zerr Pawel , Dees Clara , Distler Alfiya , Beyer Christian , Schneider Holm , Distler Oliver , Schett Georg , Allanore Yannick , Distler Jörg H. W.
Published: August 2014

Objective

Nuclear receptors regulate cell growth, differentiation, and homeostasis. Selective nuclear receptors promote fibroblast activation, which leads to tissue fibrosis, the hallmark of systemic sclerosis (SSc). This study was undertaken to investigate the effects of constitutive androstane receptor (CAR)/NR1I3, an orphan nuclear receptor, on fibroblast activation and experimental dermal fibrosis.

Methods

CAR expression was quantified by quantitative polymerase chain reaction, Western blotting, immunohistochemistry, and immunofluorescence. CAR expression was modulated by small molecules, small interfering RNA, forced overexpression, and site‐directed mutagenesis. The effects of CAR activation were analyzed in cultured fibroblasts, in bleomycin‐induced dermal fibrosis, and in mice overexpressing a constitutively active transforming growth factor β (TGFβ) receptor type I (TβRI‐CA).

Results

Up‐regulation of CAR was detected in the skin and in dermal fibroblasts in SSc patients. Stimulation of healthy fibroblasts with TGFβ induced the expression of CAR messenger RNA and protein in a Smad‐dependent manner. Pharmacologic activation or overexpression of CAR in healthy fibroblasts significantly increased the stimulatory effects of TGFβ on collagen synthesis and myofibroblast differentiation, and amplified the stimulatory effects of TGFβ on COL1A2 transcription activity. Treatment with CAR agonist increased the activation of canonical TGFβ signaling in murine models of SSc and exacerbated bleomycin‐induced and TβRI‐CA–induced fibrosis with increased dermal thickening, myofibroblast counts, and collagen accumulation.

Conclusion

Our findings indicate that CAR is up‐regulated in SSc and regulates TGFβ signaling. Activation of CAR increases the profibrotic effects of TGFβ in cultured fibroblasts and in different preclinical models of SSc. Thus, inactivation of CAR might be a novel approach to target aberrant TGFβ signaling in SSc and in other fibrotic diseases.
Gaze patterns of gross anatomy students change with classroom learning
Authors: Zumwalt Ann C. , Iyer Arjun , Ghebremichael Abenet , Frustace Bruno S. , Flannery Sean
Published: August 2014

Numerous studies have documented that experts exhibit more efficient gaze patterns than those of less experienced individuals. In visual search tasks, experts use fewer, longer fixations to fixate for relatively longer on salient regions of the visual field while less experienced observers spend more time examining nonsalient regions. This study investigates whether changes in gaze patterns reflect learning by students in a medical gross anatomy course. Students were asked to examine photographs of dissections similar to those they experienced in class and to identify the tagged structure in each image. We postulated that, compared to naive behavior (behavior at baseline and when examining unfamiliar content) students would examine familiar content for longer and would direct proportionally more fixation time on cognitively salient regions of the images while using fewer, longer duration fixations. Our students examined familiar images for significantly longer than they did at baseline (P < 0.0001) or for unfamiliar images (P < 0.0001). They also spent significantly longer examining cognitively salient regions of familiar images, as compared to examining those regions at baseline (P < 0.0001) and on unfamiliar images (P < 0.0001). However, these gaze patterns were characterized by more numerous fixations rather than fewer, longer fixations. These individuals are successful learners in a challenging gross anatomy course, but are not experts in anatomy. Therefore we speculate that the gaze pattern they exhibit characterizes an earlier stage of the learning process than has previously been documented in studies of expertise, which have primarily focused on the gaze patterns of true experts. Anat Sci Educ 8: 230–241. © 2014 American Association of Anatomists.
A New Finite Time Convergence Condition for Super‐Twisting Observer Based on Lyapunov Analysis
Authors: Mu Chaoxu , Sun Changyin
Published: August 2014

A new convergence condition is proposed for the super‐twisting sliding mode observer in this paper, where Lyapunov stability analysis is used as the main method to get the new convergence condition. The super‐twisting sliding mode observer is designed to obtain unknown system states of the second order nonlinear system with bounded uncertainties and disturbances. By involving a quadratic Lyapunov function, the Lyapunov approach is applied to the stability analysis of the super‐twisting observer, from which a new convergence condition is obtained to guarantee the finite time convergence of the observer. Simulation results of a pendulum and a rigid manipulator are included to demonstrate the effectiveness of the new convergence condition.
Treatment of spinal cord injury: A review of engineering using neural and mesenchymal stem cells
Authors: Mortazavi Martin M. , Harmon Olivia A. , Adeeb Nimer , Deep Aman , Tubbs R. Shane
Published: August 2014

Over time, various treatment modalities for spinal cord injury have been trialed, including pharmacological and nonpharmacological methods. Among these, replacement of the injured neural and paraneural tissues via cellular transplantation of neural and mesenchymal stem cells has been the most attractive. Extensive experimental studies have been done to identify the safety and effectiveness of this transplantation in animal and human models. Herein, we review the literature for studies conducted, with a focus on the human‐related studies, recruitment, isolation, and transplantation, of these multipotent stem cells, and associated outcomes. Clin. Anat. 28:37–44, 2015. © 2014 Wiley Periodicals, Inc.
Solution Synthesis, Conformational Analysis, and Antimicrobial Activity of Three Alamethicin F50/5 Analogs Bearing a Trifluoroacetyl Label
Authors: De Zotti Marta , Ballano Gema , Jost Micha , Salnikov Evgeniy S. , Bechinger Burkhard , Oancea Simona , Crisma Marco , Toniolo Claudio , Formaggio Fernando
Published: August 2014

We prepared, by solution‐phase methods, and fully characterized three analogs of the membrane‐active peptaibiotic alamethicin F50/5, bearing a single trifluoroacetyl (Tfa) label at the N‐terminus, at position 9 (central region) or at position 19 (C‐terminus), and with the three Gln at positions 7, 18, and 19 replaced by Glu(OMe) residues. To add the Tfa label at position 9 or 19, a γ‐trifluoroacetylated α,γ‐diaminobutyric acid (Dab) residue was incorporated as a replacement for the original Val9 or Glu(OMe)19 amino acid. We performed a detailed conformational analysis of the three analogs (using FT‐IR absorption, CD, 2D‐NMR, and X‐ray diffraction), which clearly showed that Tfa labeling does not introduce any dramatic backbone modification in the predominantly α‐helical structure of the parent peptaibiotic. The results of an initial solid‐state 19F‐NMR study on one of the analogs favor the conclusion that the Tfa group is a very promising reporter for the analysis of peptaibioticmembrane interactions. Finally, we found that the antimicrobial activities of the three newly synthesized analogs depend on the position of the Tfa label in the peptide sequence.
Microjaponin, A New Dihydroagarofuranoid Sesquiterpene from the Stem of Microtropis japonica with Antituberculosis Activity
Authors: Chen Jih‐Jung , Kuo Wen‐Lung , Chen Ih‐Sheng , Peng Chien‐Fang , Sung Ping‐Jyun , Cheng Ming‐Jen , Lim Yun‐Ping
Published: August 2014

A new dihydroagarofuran‐based sesquiterpene, microjaponin (1), was isolated from the stem of Microtropis japonica. Its structure was determined by in‐depth spectroscopic and mass‐spectrometric analyses. Microjaponin (1) exhibited potent in vitro antituberculosis activity, with an MIC value of 12.5 μg/ml against Mycobacterium tuberculosis H37Rv.
Phytotoxic Potential of Onopordum acanthium L. (Asteraceae)
Authors: Watanabe Yusuke , Novaes Paula , Varela Rosa M. , Molinillo José M. G. , Kato‐Noguchi Hisashi , Macías Francisco A.
Published: August 2014

Onopordum acanthium L. (Asteraceae) is a plant native to southern Europe and southwestern Asia, but it is invasive in disturbed areas and agricultural fields around the world, causing many agronomic problems by interfering with crops or preventing animals from grazing on pastures. Allelopathy could be one of the reasons that this plant has spread over different continents. The aim of the present study was to bioprospect O. acanthium leaf extracts through the isolation and purification of allelopathic secondary metabolites with phytotoxicity to explain their invasive behavior. Phytotoxic activity was tested using etiolated wheat coleoptiles. The most active extract was selected to perform a bioassay‐guided isolation of two flavonoids, pectolarigenin (1) and scutellarein 4′‐methyl ether (2), and two sesquiterpene lactones, elemanolide 11(13)‐dehydromelitensin β‐hydroxyisobutyrate (3) and acanthiolide (4). All compounds were isolated for the first time from O. acanthium, and acanthiolide (4) is described for the first time. Compound 3 strongly inhibited the growth of wheat coleoptiles and 1 showed an intermediate effect. The results indicate that these compounds could contribute to the invasion of O. acanthium in ecological systems and agricultural fields.