bluuebunny/crossref_metadata_2025 huggingface dataset:
Signal Interference Technique for Wideband Filter Design
Authors: Mondal Priyanka , Mandal Mrinal Kanti
Published: April 2014

The signal interference technique is an efficient method for the design of wideband bandpass as well as bandstop filters with sharp rejection characteristics. The signal is filtered by dividing it into two components propagating through two transmission line segments with different electrical lengths and characteristic impedances. Bandpass or bandstop response is obtained by tuning the electrical lengths and/or impedances. Coupled lines also have been used in one or both of the signal paths. As a result, different configurations of the filter are possible and each of them shows interesting features.
Assessment of the capabilities of the temporal and spatiotemporal ICA method for geophysical signal separation in GRACE data
Authors: Boergens Eva , Rangelova Elena , Sideris Michael G. , Kusche Juergen
Published: April 2014

We investigate the potential of two independent component analysis (ICA) methods, i.e., the temporal and spatiotemporal ICA, for separating geophysical signals in Gravity Recovery and Climate Experiment (GRACE) data. These methods are based on the assumption of the statistical independence of the signals and thus separate the GRACE‐observed mass changes into maximal independent signals. These two ICA methods are compared to the conventional principal component analysis (PCA) method. We test the three methods with respect to their ability to separate a periodic hydrological signal from a trend signal originating in the solid Earth or the cryosphere with simulated and Center for Space Research GRACE mass changes for the time period of January 2003 to December 2010. In addition, we investigate whether the methods are capable of separating hydrological annual and semiannual mass variations. It is shown that both ICA methods are superior to PCA when non‐Gaussian mass variations are analyzed. Furthermore, the spatiotemporal ICA resolves successfully the lack of full temporal and spatial independence of the geophysical signals observed by GRACE both in global and regional simulation scenarios. Although the temporal and spatiotemporal ICA are nearly equivalent, both superior to PCA in the global GRACE analysis, the spatiotemporal ICA proves to be more efficient in regional applications by recover more reliably the postglacial rebound trend in North America and the bimodal total water storage variability in Africa.
Quantifying aerosol direct effects from broadband irradiance and spectral aerosol optical depth observations
Authors: Creekmore Torreon N. , Joseph Everette , Long Charles N. , Li Siwei
Published: April 2014

We outline a methodology using broadband and spectral irradiances to quantify aerosol direct effects on the surface diffuse shortwave (SW) irradiance. Best Estimate Flux data span a 13 year timeframe at the Department of Energy Atmospheric Radiation Measurement Program's Southern Great Plains (SGP) site. Screened clear‐sky irradiances and aerosol optical depth (AOD), for solar zenith angles ≤ 65°, are used to estimate clear‐sky diffuse irradiances. We validate against detected clear‐sky observations from SGP's Basic Radiation System (BRS). BRS diffuse irradiances were in accordance with estimates, producing a root‐mean‐square error and mean bias errors of 4.0 W/m2 and −1.4 W/m2, respectively. Absolute differences show 99% of estimates within ±10 W/m2 (10%) of the mean BRS observations. Clear‐sky diffuse estimates are used to derive quantitative estimates of aerosol radiative effects, represented as the aerosol diffuse irradiance (ADI). ADI is the contribution of diffuse SW to global SW, attributable to scattering of atmospheric transmission by natural plus anthropogenic aerosols. Estimated slope for the ADI as a function of AOD indicates an increase of ~22 W/m2 in diffuse SW for every 0.1 increase in AOD. Such significant increases in the diffuse fraction could possibly increase photosynthesis. Annual mean ADI is 28.2 W/m2, and heavy aerosol loading at SGP provides up to a maximum increase of 120 W/m2 in diffuse SW over background conditions. With regard to seasonal variation, the mean diffuse forcings are 17.2, 33.3, 39.0, and 23.6 W/m2 for winter, spring, summer, and fall, respectively.
Modulation of monsoon intraseasonal oscillations in the recent warming period
Authors: Sabeerali C. T. , Rao Suryachandra A , George Gibies , Rao D. Nagarjuna , Mahapatra S. , Kulkarni A. , Murtugudde Raghu
Published: April 2014

The Indian Ocean sea surface temperature (SST) during the boreal summer has shown a significant warming of 0.3°C in the recent decade (2001–2010) compared to a former decade (1979–1988), and it is most pronounced in the central tropical Indian Ocean. By using reanalysis and satellite‐derived data sets, we investigated how the monsoon intraseasonal oscillation (MISO) over the South Asian summer monsoon (ASM) region has been influenced by the recent warming in the Indian Ocean. It is found that the MISO variance has increased over the ASM region in the recent period compared with the earlier decade. It is also noted that the characteristic northward propagation of the MISO has slowed over 2001–2010, resembling more of a standing oscillation near the equator. Mechanisms implicated in the observed MISO changes are explored by conducting several model sensitivity experiments with an atmospheric general circulation model. The model experiments suggest that the mean SST increase over the Indian Ocean, and the associated changes in the air‐sea interaction, the increased mean moisture convergence, and changes in the large‐scale circulation are responsible for the changes in the characteristics of the MISO. The influence of the recent Indian Ocean warming on the MISO characteristics must be understood fully since they determine the seasonal amount of rainfall over the Indian subcontinent. An examination of future projections of the MISO using the MPI‐ESM‐LR model from the Coupled Model Intercomparison Project phase 5 archive also gives consistent result.
A transient deep‐sea circulation switch during Eocene Thermal Maximum 2
Authors: D'haenens Simon , Bornemann André , Claeys Philippe , Röhl Ursula , Steurbaut Etienne , Speijer Robert P.
Published: April 2014

Ever since its discovery, Eocene Thermal Maximum 2 (ETM2; ~53.7 Ma) has been considered as one of the “little brothers” of the Paleocene‐Eocene Thermal Maximum (PETM; ~56 Ma) as it displays similar characteristics including abrupt warming, ocean acidification, and biotic shifts. One of the remaining key questions is what effect these lesser climate perturbations had on ocean circulation and ventilation and, ultimately, biotic disruptions. Here we characterize ETM2 sections of the NE Atlantic (Deep Sea Drilling Project Sites 401 and 550) using multispecies benthic foraminiferal stable isotopes, grain size analysis, XRF core scanning, and carbonate content. The magnitude of the carbon isotope excursion (0.85–1.10‰) and bottom water warming (2–2.5°C) during ETM2 seems slightly smaller than in South Atlantic records. The comparison of the lateral δ13C gradient between the North and South Atlantic reveals that a transient circulation switch took place during ETM2, a similar pattern as observed for the PETM. New grain size and published faunal data support this hypothesis by indicating a reduction in deepwater current velocity. Following ETM2, we record a distinct intensification of bottom water currents influencing Atlantic carbonate accumulation and biotic communities, while a dramatic and persistent clay reduction hints at a weakening of the regional hydrological cycle. Our findings highlight the similarities and differences between the PETM and ETM2. Moreover, the heterogeneity of hyperthermal expression emphasizes the need to specifically characterize each hyperthermal event and its background conditions to minimalize artifacts in global climate and carbonate burial models for the early Paleogene.
Inference of permeability heterogeneity from joint inversion of transient flow and temperature data
Authors: Zhang Zhishuai , Jafarpour Behnam , Li Lianlin
Published: April 2014

Characterization of the rock permeability distribution in compartmentalized deep aquifers, enhanced geothermal systems, and hydrocarbon reservoirs is important for predicting the flow and transport behavior in these formations. Reliable prediction of the fluid flow and transport processes can, in turn, lead to effective development of the subsurface energy and environmental resources. In deep formations where thermal gradients are significant, the transient temperature data can provide valuable information about the permeability distribution with depth and about the vertical fluid displacement. This paper examines the importance of temperature data in resolving the distribution of permeability with depth by jointly, and individually, integrating the transient temperature and flow data. We demonstrate that when estimating permeability distributions in deep geothermal reservoirs, incorporating temperature data can increase the resolution of the permeability distribution profile with depth. To illustrate the importance of temperature measurements, we adopt a coupled transient heat and fluid flow as a forward model to predict the heat and fluid transport in a geothermal reservoir and develop an adjoint model for efficient computation of the gradient information for model calibration. We perform a series of numerical experiments for integration of flow and pressure data alone, temperature data alone, and flow and pressure jointly with temperature data. In each case, we apply the maximum A‐posteriori (MAP) method and the randomized maximum likelihood (RML) method for inversion and uncertainty quantification. Analysis of the sensitivity of temperature and production data to heterogeneous permeability distributions reveals that the temperature of fluid, even when measured at the surface, is sensitive to the permeability distribution in the vertical extent of the reservoir. Hence, temperature measurements can be augmented with flow‐related data to enhance the resolution of the estimated permeability field with depth.
Earth System Studies in Northern Eurasia
Authors: Groisman Pavel , Gulev Sergey , Maksyutov Shamil
Published: April 2014

During recent decades, northern Eurasia (north of 40°N and east of 15°E) was affected by unprecedented climate and environmental changes. Several droughts, including a heat wave in 2010 (that in European Russia may have been the cause of up to an additional 60,000 deaths in July–August of that year, compared to the previous year; see http://ifaran.ru/science/seminars/Summer2010.html); alternated with hazardous extreme precipitation and flood events. Permafrost thaw, retreating Arctic sea ice, increasing areas of forest fire, and dramatic regional warming buffeted this region, tossing northern Eurasia from one extreme condition to the next.
Climate Report Focuses on Mitigation Measures
Authors: Showstack Randy
Published: April 2014

Without additional efforts to reduce greenhouse gas emissions beyond the efforts that are already in place, emissions growth could result in significantly higher global mean surface temperatures by 2100, according to a 13 April report by a working group of the Intergovernmental Panel on Climate Change (IPCC).
Basic Theory Behind Parameterizing Atmospheric Convection
Authors: Plant R. S. , Fuchs Z. , Yano J. I.
Published: April 2014

Last fall, a network of the European Cooperation in Science and Technology (COST), called “Basic Concepts for Convection Parameterization in Weather Forecast and Climate Models” (COST Action ES0905; see http://w3.cost.esf.org/index.php?id=205&action_number=ES0905), organized a 10‐day training course on atmospheric convection and its parameterization. The aim of the workshop, held on the island of Brac, Croatia, was to help young scientists develop an in‐depth understanding of the core theory underpinning convection parameterizations. The speakers also sought to impart an appreciation of the various approximations, compromises, and ansatz necessary to translate theory into operational practice for numerical models.
First siting of deep lee waves: Kaena Ridge, Hawaii
Authors: Wendel JoAnna
Published: April 2014

Turbulent mixing in the ocean has important effects on climate and the transport of energy and nutrients. Internal lee waves, which are underwater standing waves that result from a current flowing over a barrier, have become recognized as an important source of mixing in the ocean. Previous studies with remote observations and numerical models have predicted the existence of breaking deep internal lee waves driven by the tide, but until now, none have been observed directly.
Remanent magnetism of sediment governs magnetofossil alignment
Authors: Wendel JoAnna
Published: April 2014

Most bacteria navigate by reacting to different chemical signals in their surroundings, but some bacteria have another navigational tool in their arsenal—the Earth's magnetic field. Nestled inside these magnetotactic bacteria (MTB) are organelles called magnetosomes, filled with tiny magnetic crystals and arranged in chains, which form nano‐sized compass needles. When MTB die and degrade, these tiny crystals can remain in sediment and eventually become magnetic fossils called magnetofossils.
Data‐driven numerical simulations of equatorial spread F in the Peruvian sector
Authors: Hysell D. L. , Jafari R. , Milla M. A. , Meriwether J. W.
Published: April 2014

Ionospheric state parameters including plasma number density and vector drift velocity profiles were measured at the Jicamarca Radio Observatory during a campaign running from 12 to 18 April 2013. Neutral winds were measured by the red‐line Fabry Perot interferometer at Jicamarca. Coherent radar backscatter from plasma irregularities associated with equatorial spread F (ESF) was also recorded. A numerical simulation of ionospheric irregularities, initialized and forced using parameterizations derived from a combination of measurements and empirical models, was used to try to reproduce the ESF activity that occurred on three different nights. Simulations were able to recover the salient features of the irregularities that formed in each case and produce bottom‐type, bottomside, and topside ESF. Realistic simulations require the accurate representation of the vertical currents that generate irregularities initially at the base of the F region as well as the zonal currents necessary for irregularities to expand in altitude and penetrate to the topside. The campaign data, numerical simulations, and protocols used to associate them are presented and evaluated.
Some aspects of the problem of secondary eyewall formation in idealized three‐dimensional nonlinear simulations
Authors: Menelaou K. , Yau M. K. , Martinez Y.
Published: April 2014

Some aspects of the problem of secondary eyewall formation (SEF) are investigated with the aid of an idealized model. A series of experiments are conducted, starting with a strong annular vortex embedded in a quiescent background flow and forced by the sustained heating associated with a spiral rainband (control experiment). Following this, two experiments are configured to assess the impact of vertical wind shear (VWS) in the SEF process. The importance of the boundary layer force imbalance is finally investigated in a number of simulations in which surface and boundary layer physics are included. From the control experiment, it is found that in the absence of background environmental flow, the sustained latent heating associated with a spiral rainband can form a secondary eyewall even in the absence of a frictional boundary layer. The presence of VWS acts negatively in the SEF process by disrupting the organization of the potential vorticity induced by the rainband. When boundary layer physics is included, some similarities with previous studies are seen, but there is no SEF. These results suggest that the boundary layer most likely contributes to, rather than initiate, a secondary eyewall.
Rapid and sustained surface ocean acidification during the Paleocene‐Eocene Thermal Maximum
Authors: Penman Donald E. , Hönisch Bärbel , Zeebe Richard E. , Thomas Ellen , Zachos James C.
Published: April 2014

The Paleocene‐Eocene Thermal Maximum (PETM) has been associated with the release of several thousands of petagrams of carbon (Pg C) as methane and/or carbon dioxide into the ocean‐atmosphere system within ~10 kyr, on the basis of the co‐occurrence of a carbon isotope excursion (CIE), widespread dissolution of deep sea carbonates, and global warming. In theory, this rapid carbon release should have severely acidified the surface ocean, though no geochemical evidence has yet been presented. Using boron‐based proxies for surface ocean carbonate chemistry, we present the first observational evidence for a drop in the pH of surface and thermocline seawater during the PETM. Planktic foraminifers from a drill site in the North Pacific (Ocean Drilling Program Site 1209) show a ~0.8‰ decrease in boron isotopic composition (δ11B) at the onset of the event, along with a 30–40% reduction in shell B/Ca. Similar trends in δ11B are present in two lower‐resolution records from the South Atlantic and Equatorial Pacific. These observations are consistent with significant, global acidification of the surface ocean lasting at least 70 kyr and requiring sustained carbon release. The anomalies in the B records are consistent with an initial surface pH drop of ~0.3 units, at the upper range of model‐based estimates of acidification.
Carbon‐Fiber‐Reinforced Silicon Carbide: a New Brake Disk Material
Authors: Kienzle Andreas , Jäger Hubert
Published: April 2014

Since 1950, the top speed of luxury class limousines increased from around 180 to 250 km/h in the year 2010. In the same time, also the car weight increased from around 1400 to 2500 kg. This leads to higher kinetic energy, which results in a lower lifetime of the metal disks and fading problems, with the result of longer stopping distances. In the past decade, the carbon‐fiber‐reinforced silicon carbide brake disk material is developed. The material is produced by liquid siliconization of porous carbon‐fiber‐reinforced carbon preform with liquid silicon under vacuum. The resulting material shows a low weight because of the low densities of around 2.3 gcm
−3
and high hardness. At the Frankfurt Motor Show in 1999, the carbon‐ceramic brake disk was shown the first time to the public. At present, for nearly all high end sport and luxury cars,
CF
/
SiC
brake disks are available. In this contribution, the production processes of the
CF
/
SiC
disks are described and an overview of the
CF
/
SiC
material and brake disk behavior is given.
Choosing Wisely: The American College of Rheumatology's Top 5 for Pediatric Rheumatology
Authors: Rouster‐Stevens Kelly A. , Ardoin Stacy P. , Cooper Ashley M. , Becker Mara L. , Dragone Leonard L. , Huttenlocher Anna , Jones Karla B. , Kolba Karen S. , Moorthy L. Nandini , Nigrovic Peter A. , Stinson Jennifer N. , Ferguson Polly J. ,   for the American College of Rheumatology Pediatric Rheumatology Core Membership Group
Published: April 2014

Objective

To create a pediatric rheumatology Top 5 list as part of the American Board of Internal Medicine Foundation's Choosing Wisely campaign.

Methods

Delphi surveys of a core group of representative pediatric rheumatology providers from across North America generated candidate Top 5 items. Items with high content agreement and perceived to be of prevalent use and of high impact were included in a survey of all American College of Rheumatology (ACR) members who identified themselves as providing care to pediatric patients. Items with the highest ratings were subjected to literature review and further evaluation.

Results

A total of 121 candidate items were proposed in the initial Delphi survey and were reduced to 28 items in subsequent surveys. These 28 items were sent to 1,198 rheumatology providers who care for pediatric patients, and 397 (33%) responded. Based upon survey data and literature review, the Top 5 items were identified. These items focused on testing for antinuclear antibodies, autoantibody panels, Lyme disease, methotrexate toxicity monitoring, and use of routine radiographs.

Conclusion

The ACR pediatric rheumatology Top 5 is one of the first pediatric subspecialty–specific Choosing Wisely Top 5 lists and provides an opportunity for patients and providers to discuss appropriate use of health care in pediatric rheumatology.
Development and Validation of the Lupus Impact Tracker: A Patient‐Completed Tool for Clinical Practice to Assess and Monitor the Impact of Systemic Lupus Erythematosus
Authors: Jolly Meenakshi , Garris Cindy P. , Mikolaitis Rachel A. , Jhingran Priti M. , Dennis Greg , Wallace Daniel J. , Clarke Ann , Dooley Mary Anne , Parke Ann , Strand Vibeke , Alárcon Graciela S. , Kosinski Mark
Published: April 2014

Objective

To derive and validate a brief patient‐completed instrument, the Lupus Impact Tracker (LIT), to assess and monitor the impact of systemic lupus erythematosus (SLE).

Methods

Items for the LIT were selected from the LupusPRO, a validated patient‐reported outcomes measure, using 3 approaches: confirmatory factor analysis (CFA), stepwise regression, and patient focus groups. CFA was conducted to find items from the LupusPRO that fit a unidimensional structure to allow scoring as a single index. Stepwise regression methods identified items with the strongest relationship (convergent validity) with disease activity measures and patient health rating. Focus groups (n = 26 patients) identified the most important items describing SLE impact. Selected items were evaluated for reliability and validity.

Results

CFA found 21 items that fit a unidimensional structure. Stepwise regressions identified 15 of 21 items having good convergent validity with clinical measures. Patient focus groups identified 9 of 15 items as best capturing the impact of SLE. Overall, 7 items were selected across all 3 approaches (CFA, stepwise regression, and focus groups). Another 15 items were selected across 2 approaches. Through consensus with rheumatology clinician experts, a final set of 10 items was selected for the LIT. The LIT items showed good internal consistency (0.89) and test–retest reliabilities (0.87). Mean LIT scores differed significantly (P < 0.05) across criterion groups in the hypothesized direction, providing evidence of discriminant validity and responsiveness.

Conclusion

The LIT is reliable and valid in SLE patients and offers a practical way for physicians and patients to assess and monitor the impact of SLE.
Parental Influence on Systemic Sclerosis
Authors: Frech Tracy M. , Pimentel Richard , Mineau Geraldine , Sawitzke Allen , Penmetsa Gopi , Wong Jathine
Published: April 2014

Objective

To examine parental influence on the development of systemic sclerosis (SSc; scleroderma). We designed 3 studies: mitochondrial inheritance, birth order (a possible surrogate marker for microchimerism), and paternal age at conception (a possible surrogate for telomere erosion) to examine their association with development of SSc.

Methods

SSc was defined by International Classification of Diseases, Ninth and Tenth Revision codes (ICD‐9 710.1 and ICD 10 M34.0, M34.1, and M34.9) and identified from statewide discharge data, University of Utah Health Science Center Enterprise Data Warehouse (UUHSC), and death certificates that were linked to the Utah Population Database (UPDB) for analysis. Mitochondrial inheritance was evaluated by conditional logistic regression and population attributable risk using familial standardized incidence ratio as the covariate. Chi‐square test and logistic regression were used to evaluate birth order and maternal/paternal age at conception of the SSc proband.

Results

We found 1,947 unique SSc patients from UUHSC and UPDB. We selected 5 controls per case (n = 9,115), matched by birth year and sex. Mitochondrial inheritance analysis indicated no evidence to suggest SSc was associated with mitochondrial inheritance. Birth order and maternal/paternal age at conception analysis results show that they also do not significantly affect SSc development.

Conclusion

Results suggest that although heritable risk of SSc is observed, mitochondrial inheritance, birth order, and parental age are not likely responsible for pathogenesis.
Fabrication of Periodic Nanostructure Assemblies by Interfacial Energy Driven Colloidal Lithography
Authors: Dev A. , Dev Choudhury B. , Abedin A. , Anand S.
Published: April 2014

A novel interfacial energy driven colloidal lithography technique to fabricate periodic patterns from solution‐phase is presented and the feasibility and versatility of the technique is demonstrated by fabricating periodically arranged ZnO nanowire ensembles on Si substrates. The pattern fabrication method exploits different interfaces formed by sol–gel derived ZnO seed solution on a hydrophobic Si surface covered by a monolayer of colloidal silica spheres. While the hydrophobic Si surface prevents wetting by the seed solution, the wedge shaped regions surrounding the contact point between the colloidal particles and the Si substrate trap the solution due to interfacial forces. This technique allows fabrication of uniform 2D micropatterns of ZnO seed particles on the Si substrate. A hydrothermal technique is then used to grow well‐defined periodic assemblies of ZnO nanowires. Tunability is demonstrated in the dimensions of the patterns by using silica spheres with different diameters. The experimental data show that the periodic ZnO nanowire assembly suppresses the total reflectivity of bare Si by more than a factor of 2 in the wavelength range 400–1300 nm. Finite‐difference time‐domain simulations of the wavelength‐dependent reflectivity show good qualitative agreement with the experiments. The demonstrated method is also applicable for other materials synthesized by solution chemistry.
Highly Tunable Elastomeric Silk Biomaterials
Authors: Partlow Benjamin P. , Hanna Craig W. , Rnjak‐Kovacina Jelena , Moreau Jodie E. , Applegate Matthew B. , Burke Kelly A. , Marelli Benedetto , Mitropoulos Alexander N. , Omenetto Fiorenzo G. , Kaplan David L.
Published: April 2014

Elastomeric, fully degradable, and biocompatible biomaterials are rare, with current options presenting significant limitations in terms of ease of functionalization and tunable mechanical and degradation properties. A new method for covalently crosslinking tyrosine residues in silk proteins, via horseradish peroxidase and hydrogen peroxide, to generate highly elastic hydrogels with tunable properties, is reported. These materials offer tunable mechanical properties, gelation kinetics, and swelling properties. In addition, these new polymers withstand shear strains on the order of 100%, compressive strains greater than 70% and display stiffness between 200–10 000 Pa, covering a significant portion of the properties of native soft tissues. Molecular weight and solvent composition allow control of material mechanical properties over several orders of magnitude while maintaining high resilience and resistance to fatigue. Encapsulation of human bone marrow derived mesenchymal stem cells (hMSC) shows long term survival and exhibits cell‐matrix interactions reflective of both silk concentration and gelation conditions. Further biocompatibility of these materials is demonstrated with in vivo evaluation. These new protein‐based elastomeric and degradable hydrogels represent an exciting new biomaterials option, with a unique combination of properties, for tissue engineering and regenerative medicine.
A Family of High‐Performance Cathode Materials for Na‐ion Batteries, Na3(VO1−xPO4)2 F1+2x (0 ≤ x ≤ 1): Combined First‐Principles and Experimental Study
Authors: Park Young‐Uk , Seo Dong‐Hwa , Kim Hyungsub , Kim Jongsoon , Lee Seongsu , Kim Byoungkook , Kang Kisuk
Published: April 2014

Room‐temperature Na‐ion batteries (NIBs) have recently attracted attention as potential alternatives to current Li‐ion batteries (LIBs). The natural abundance of sodium and the similarity between the electrochemical properties of NIBs and LIBs make NIBs well suited for applications requiring low cost and long‐term reliability. Here, the first successful synthesis of a series of Na3(VO1−x
PO4)2F1+2x
(0 ≤ x ≤ 1) compounds as a new family of high‐performance cathode materials for NIBs is reported. The Na3(VO1−x
PO4)2F1+2x
series can function as high‐performance cathodes for NIBs with high energy density and good cycle life, although the redox mechanism varies depending on the composition. The combined first‐principles calculations and experimental analysis reveal the detailed structural and electrochemical mechanisms of the various compositions in solid solutions of Na3(VOPO4)2F and Na3V2(PO4)2F3. The comparative data for the Na
y
(VO1−x
PO4)2F1+2x
electrodes show a clear relationship among V3+/V4+/V5+ redox reactions, Na+−Na+ interactions, and Na+ intercalation mechanisms in NIBs. The new family of high‐energy cathode materials reported here is expected to spur the development of low‐cost, high‐performance NIBs.
Gel Scaffolds of BMP‐2‐Binding Peptide Amphiphile Nanofibers for Spinal Arthrodesis
Authors: Lee Sungsoo S. , Hsu Erin L. , Mendoza Marco , Ghodasra Jason , Nickoli Michael S. , Ashtekar Amruta , Polavarapu Mahesh , Babu Jacob , Riaz Rehan M. , Nicolas Joseph D. , Nelson David , Hashmi Sohaib Z. , Kaltz Stuart R. , Earhart Jeffrey S. , Merk Bradley R. , McKee Jeff S. , Bairstow Shawn F. , Shah Ramille N. , Hsu Wellington K. , Stupp Samuel I.
Published: April 2014

Peptide amphiphile (PA) nanofibers formed by self‐assembly can be customized for specific applications in regenerative medicine through the use of molecules that display bioactive signals on their surfaces. Here, the use of PA nanofibers with binding affinity for the bone promoting growth factor BMP‐2 to create a gel scaffold for osteogenesis is reported. With the objective of reducing the amount of BMP‐2 used clinically for successful arthrodesis in the spine, amounts of growth factor incorporated in the scaffolds that are 10 to 100 times lower than that those used clinically in collagen scaffolds are used. The efficacy of the bioactive PA system to promote BMP‐2‐induced osteogenesis in vivo is investigated in a rat posterolateral lumbar intertransverse spinal fusion model. PA nanofiber gels displaying BMP‐2‐binding segments exhibit superior spinal fusion rates relative to controls, effectively decreasing the required therapeutic dose of BMP‐2 by 10‐fold. Interestingly, a 42% fusion rate is observed for gels containing the bioactive nanofibers without the use of exogenous BMP‐2, suggesting the ability of the nanofiber to recruit endogenous growth factor. Results obtained here demonstrate that bioactive biomaterials with capacity to bind specific growth factors by design are great targets for regenerative medicine.
Interfacial Engineering of P3HT/ZnO Hybrid Solar Cells Using Phthalocyanines: A Joint Theoretical and Experimental Investigation
Authors: Mattioli Giuseppe , Dkhil Sadok Ben , Saba Maria Ilenia , Malloci Giuliano , Melis Claudio , Alippi Paola , Filippone Francesco , Giannozzi Paolo , Thakur Anil Kumar , Gaceur Meriem , Margeat Olivier , Diallo Abdou Karim , Videlot‐Ackermann Christine , Ackermann Jörg , Bonapasta Aldo Amore , Mattoni Alessandro
Published: April 2014

Atomistic simulations and experimental investigations are combined to study heterojunction interfaces of hybrid polymer solar cells, with the aim to better understand and precisely predict their photovoltaic properties. The focus is on a hybrid ternary model system based on a poly(3‐hexylthiophene) (P3HT)/zinc phthalocyanine (ZnPc)/ZnO interface, in which a ZnPc interlayer is applied to improve the performance of the hybrid interface. Theoretical predictions of the ternary system are validated against the properties of a concrete P3HT/ZnPc/ZnO planar heterojunction device. The theoretical predictions closely agree with the photovoltaic properties obtained in P3HT/ZnPc/ZnO solar cells, indicating the strength of the method for modeling hybrid heterojunction interfaces. The theoretical and experimental results reveal that: i) ZnPc molecules in direct contact with a ZnO surface insert new energy levels due to a strong ZnPc/ZnO coupling, ii) electron injection from these new energy levels of ZnPc into ZnO is highly efficient, iii) the ZnPc/ZnO coupling strongly influences the energy levels of the ZnO and P3HT leading to a reduction of the open circuit voltage, and iv) charge carrier recombination at the P3HT/ZnO interface is reduced by the ZnPc interlayer. The intercalation of ZnPc leads to an increase in photocurrent as well as to an overall increase in power conversion.
Metallic Photonic Crystal Absorber‐Emitter for Efficient Spectral Control in High‐Temperature Solar Thermophotovoltaics
Authors: Rinnerbauer Veronika , Lenert Andrej , Bierman David M. , Yeng Yi Xiang , Chan Walker R. , Geil Robert D. , Senkevich Jay J. , Joannopoulos John D. , Wang Evelyn N. , Soljačić Marin , Celanovic Ivan
Published: April 2014

A high‐temperature stable solar absorber based on a metallic 2D photonic crystal (PhC) with high and tunable spectral selectivity is demonstrated and optimized for a range of operating temperatures and irradiances. In particular, a PhC absorber with solar absorptance 0.86 and thermal emittance = 0.26 at 1000 K, using high‐temperature material properties, is achieved resulting in a thermal transfer efficiency more than 50% higher than that of a blackbody absorber. Furthermore, an integrated double‐sided 2D PhC absorber/emitter pair is demonstrated for a high‐performance solar thermophotovoltaic (STPV) system. The 2D PhC absorber/emitter is fabricated on a double‐side polished tantalum substrate, characterized, and tested in an experimental STPV setup along with a flat Ta absorber and a nearly blackbody absorber composed of an array of multiwalled carbon nanotubes (MWNTs). At an irradiance of 130 kW m−2 the PhC absorber enables more than a two‐fold improvement in measured STPV system efficiency (3.74%) relative to the nearly blackbody absorber (1.60%) and higher efficiencies are expected with increasing operating temperature. These experimental results show unprecedented high efficiency, demonstrating the importance of the high selectivity of the 2D PhC absorber and emitter for high‐temperature energy conversion.
Organocatalytic Asymmetric Condensation/Keto–Enol Tautomerization Tandem Reaction: Access to Cyclobutanone α‐Amino Acid Ester Derivatives
Authors: Frongia Angelo , Melis Nicola , Serra Ilaria , Secci Francesco , Piras Pier Paolo , Caboni Pierluigi
Published: April 2014

A practical method for the synthesis of optically active α‐amino cyclobutanones has been developed, via an organocatalytic asymmetric condensation reaction between racemic 2‐hydroxycyclobutanone and chiral N‐alkyl‐α‐amino acid ester derivatives.
Übergangsmetallfreie BF3‐vermittelte oxidative und nichtoxidative Kreuzkupplung von Pyridinen
Authors: Chen Quan , León Thierry , Knochel Paul
Published: April 2014

Wir berichten über eine BF3‐vermittelte direkte Alkinylierung von Pyridinen an C(2) mit verschiedenen Alkinyllithiumreagentien (oxidative Kreuzkupplung). Zudem entwickelten wir eine neuartige, übergangsmetallfreie Methode zur Kreuzkupplung von Alkylmagnesiumreagentien mit 4‐substituierten Pyridinen, wie Isonicotinnitril und 4‐Chlorpyridin, mit BF3⋅OEt2 als Vermittlungsreagens. Die Kombination dieser beiden Methoden ermöglicht uns die effiziente Synthese einer Reihe von di‐, tri‐ und tetrasubstituierten Pyridinen.
Single‐step oxidative homocoupling of aryl Grignard reagents via Co(II), Ni(II) and Cu(II) Complexes under air
Authors: Bhat Aparna P. I. , Bhat Badekai Ramachandra
Published: April 2014

A simple catalytic system of direct synthesis for the symmetrical biaryls using catalytic amounts of Co(II), Ni(II) and Cu(II) complexes has been developed. The reaction system involves in situ synthesis of Grignard reagents. The complexes, containing bidentate Schiff base and dmit (2‐thioxo‐1,3‐dithiole‐4,5‐dithiolate) ligands, were compatible with diverse functionalities and afford a high yield of biaryls in a single step, proving to be promising catalysts in homocoupling reactions. Atmospheric oxygen is used as an oxidant which renders a green, simple and economical catalytic route. Copyright © 2014 John Wiley & Sons, Ltd.
Mechanical, chemical, thermal, and rheological properties of recycled PA6/ABS binary and PA6/PA66/ABS ternary blends
Authors: Kuram Emel , Sarac Levent , Ozcelik Babur , Yilmaz Faruk
Published: April 2014

The effects of multiple injection molding cycles on the chemical and mechanical properties of PA6/ABS and PA6/PA66/ABS blends are investigated. The chemical structures of both PA6/ABS binary and PA6/PA66/ABS ternary blends do not alter after recycling process. For PA6/ABS binary blend, it is found that the tensile strength, strain at break, elastic modulus, impact strength, flexural strength, and modulus of recycled blend decrease by 6.49%, 15.19%, 21.00%, 9.41%, 7.09%, and 8.25%, respectively, while MFI increases by 23.59% as compared with the virgin blend. After five recycling process for PA6/PA66/ABS ternary blend, the tensile strength, strain at break, and impact strength of recycled blend decrease by 18.00%, 50.80%, and 87.27%, respectively. However, flexural strength and modulus of PA6/PA66/ABS blend increase slightly. For virgin PA6/PA66/ABS blend, MFI value was 7.7 g/10 min and with recycling this value showed an important increase to 31.56 g/10 min after five cycles. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40810.
Synthesis and electrochemical properties of graphene oxide/nanosulfur/polypyrrole ternary nanocomposite hydrogel for supercapacitors
Authors: Chen Chunnian , Fu Xuwang , Ma Ting , Fan Wei , Wang Zhongbing , Miao Shiding
Published: April 2014

A method for synthesizing Graphene oxide (GO)/nano‐sulfur/polypyrrole (PPy) ternary nanocomposite hydrogel is depicted. The higher surface area of GO, PPy porous structure and their excellent conductivity are utilized, and the GO hydrogel can be made easily. The products are characterized by field‐emission scanning electron microscopy (FESEM), X‐ray diffraction (XRD), Fourier transform infrared (FTIR) spectra, and electrochemical workstation. The results demonstrated that GO/nano‐S/PPy ternary nanocomposite hydrogel is successfully synthesized. The electrochemical properties are investigated by cyclic voltammetry, galvanostatic charge/discharge measurements, and cycling life in a three‐electrode system in 1MLi2SO4electrolyte solution. The GO/nano‐S/PPy ternary nanocomposite hydrogel exhibit a high specific capacitance of 892.5 F g−1at scan rates of 5 mV s−1and the capacitance retain about 81.2% (594.8 F g−1) of initial capacitance (732.5 F g−1) after 500 cycles at a current density of 1 A g−1. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2014,131, 40814.
Use of Whole‐Blood Transcriptomic Profiling to Highlight Several Pathophysiologic Pathways Associated With Response to Rituximab in Patients With Rheumatoid Arthritis: Data From a Randomized, Controlled, Open‐Label Trial
Authors: Sellam Jérémie , Marion‐Thore Sandrine , Dumont Florent , Jacques Sébastien , Garchon Henri‐Jean , Rouanet Stéphanie , Taoufik Yassine , Hendel‐Chavez Houria , Sibilia Jean , Tebib Jacques , Le Loët Xavier , Combe Bernard , Dougados Maxime , Mariette Xavier , Chiocchia Gilles
Published: April 2014

Objective

To identify a molecular signature that could be predictive of the clinical response to rituximab (RTX) and elucidate the transcriptomic changes after RTX therapy in patients with rheumatoid arthritis (RA), with the use of whole‐blood transcriptomic profiling.

Methods

A microarray assay of the whole human genome was performed using RNA from peripheral blood samples obtained before the first cycle of RTX from 68 patients with RA in the SMART study. The transcriptomic profile was also assessed 24 weeks after the first administration of RTX (among 24 nonresponders and 44 responders, according to the European League Against Rheumatism response criteria at week 24). Ingenuity Interactive Pathways Analysis was used to identify molecular pathways that were modified by RTX therapy according to the clinical response. Quantitative polymerase chain reaction was performed to confirm the microarray results.

Results

In total, 198 genes showed significant baseline differential expression between patient groups according to their subsequent response to RTX (good or moderate responder versus nonresponder). This molecular signature could be reduced to 143 genes, which allowed for correctly classifying 89% of the patients by their EULAR response status at week 24, with 93% identification of responders and 100% identification of nonresponders. The signature for response featured up‐regulation of inflammatory genes centered on NF‐κB, including IL33 and STAT5A, and down‐regulation of the interferon pathway. As expected, at week 24 post–RTX therapy, genes involved in the development and functions of B cells were the genes most strongly down‐regulated, without any difference between the 2 groups.

Conclusion

Whole‐blood transcriptomic analyses may accurately identify patients with RA who will not respond to RTX therapy. These findings could open new perspectives on the clinical management of RA.
A CD8 T Cell/Indoleamine 2,3‐Dioxygenase Axis Is Required for Mesenchymal Stem Cell Suppression of Human Systemic Lupus Erythematosus
Authors: Wang Dandan , Feng Xuebing , Lu Lin , Konkel Joanne E. , Zhang Huayong , Chen Zhiyong , Li Xia , Gao Xiang , Lu Liwei , Shi Songtao , Chen Wanjun , Sun Lingyun
Published: April 2014

Objective

Allogeneic mesenchymal stem cells (MSCs) exhibit therapeutic effects in human autoimmune diseases such as systemic lupus erythematosus (SLE), but the underlying mechanisms remain largely unknown. The aim of this study was to investigate how allogeneic MSCs mediate immunosuppression in lupus patients.

Methods

The effects of allogeneic umbilical cord–derived MSCs (UC‐MSCs) on inhibition of T cell proliferation were determined. MSC functional molecules were stimulated with peripheral blood mononuclear cells from healthy controls and SLE patients and examined by real‐time polymerase chain reaction. CD4+ and CD8+ T cells were purified using microbeads to stimulate MSCs in order to determine cytokine expression by MSCs and to further determine which cell subset(s) or which molecule(s) is involved in inhibition of MSC–mediated T cell proliferation. The related signaling pathways were assessed. We determined levels of serum cytokines in lupus patients before and after UC‐MSC transplantation.

Results

Allogeneic UC‐MSCs suppressed T cell proliferation in lupus patients by secreting large amounts of indoleamine 2,3‐dioxygenase (IDO). We further found that interferon‐γ (IFNγ), which is produced predominantly by lupus CD8+ T cells, is the key factor that enhances IDO activity in allogeneic MSCs and that it is associated with IFNGR1/JAK‐2/STAT signaling pathways. Intriguingly, bone marrow–derived MSCs from patients with active lupus demonstrated defective IDO production in response to IFNγ and allogeneic CD8+ T cell stimulation. After allogeneic UC‐MSC transplantation, serum IDO activity increased in lupus patients.

Conclusion

We found a previously unrecognized CD8+ T cell/IFNγ/IDO axis that mediates the therapeutic effects of allogeneic MSCs in lupus patients.
Correlation of CXCL10, Tumor Necrosis Factor Receptor Type II, and Galectin 9 With Disease Activity in Juvenile Dermatomyositis
Authors: Bellutti Enders F. , van Wijk F. , Scholman R. , Hofer M. , Prakken B. J. , van Royen‐Kerkhof A. , de Jager W.
Published: April 2014

Objective

Juvenile dermatomyositis (DM) is a systemic autoimmune disorder of unknown immunopathogenesis in which the immune system targets the microvasculature of skeletal muscles, skin, and other organs. The current mainstay of therapy is a steroid regimen in combination with other immunosuppressive treatments. To date, no validated markers for monitoring disease activity have been identified, which hampers personalized treatment. This study was undertaken to identify a panel of proteins specifically related to active disease in juvenile DM.

Methods

We performed a multiplex immunoassay for plasma levels of 45 proteins related to inflammation in 25 patients with juvenile DM in 4 clinically well‐defined groups, as determined by clinical activity and treatment. We compared them to 14 age‐matched healthy children and 8 age‐matched children with nonautoimmune muscle disease.

Results

Cluster analysis of circulating proteins showed distinct profiles for juvenile DM patients and controls based on a group of 10 proteins. In addition to CXCL10, tumor necrosis factor receptor type II (TNFRII) and galectin 9 were significantly increased in active juvenile DM. The levels of these 3 proteins were tightly linked to active disease and correlated with clinical scores (as measured by the Childhood Myositis Assessment Scale and physician's global assessment of disease activity on a visual analog scale).

Conclusion

Our findings indicate that CXCL10, TNFRII, and galectin 9 correspond to disease status in juvenile DM and thus could be helpful in monitoring disease activity and guiding treatment. Furthermore, they might provide new knowledge about the pathogenesis of this autoimmune disease.
Identification of Stage‐Specific Genes Associated With Lupus Nephritis and Response to Remission Induction in (NZB × NZW)F1 and NZM2410 Mice
Authors: Bethunaickan Ramalingam , Berthier Celine C. , Zhang Weijia , Eksi Ridvan , Li Hong‐Dong , Guan Yuanfang , Kretzler Matthias , Davidson Anne
Published: April 2014

Objective

To elucidate the molecular mechanisms involved in renal inflammation during the progression, remission, and relapse of nephritis in murine lupus models using transcriptome analysis.

Methods

Kidneys from (NZB × NZW)F1 (NZB/NZW) and NZM2410 mice were harvested at intervals during the disease course or after remission induction. Genome‐wide expression profiles were obtained from microarray analysis of perfused kidneys. Real‐time polymerase chain reaction (PCR) analysis for selected genes was used to validate the microarray data. Comparisons between groups using SAM, and unbiased analysis of the entire data set using singular value decomposition and self‐organizing maps were performed.

Results

Few changes in the renal molecular profile were detected in prenephritic kidneys, but a significant shift in gene expression, reflecting inflammatory cell infiltration and complement activation, occurred at proteinuria onset. Subsequent changes in gene expression predominantly affected mitochondrial dysfunction and metabolic stress pathways. Endothelial cell activation, tissue remodeling, and tubular damage were the major pathways associated with loss of renal function. Remission induction reversed most, but not all, of the inflammatory changes, and progression toward relapse was associated with recurrence of inflammation, mitochondrial dysfunction, and metabolic stress signatures.

Conclusion

Immune cell infiltration and activation is associated with proteinuria onset and is reversed by immunosuppressive therapy, but disease progression is associated with renal hypoxia and metabolic stress. Optimal therapy for lupus nephritis may therefore need to target both immune and nonimmune disease mechanisms. In addition, the overlap of a substantial subset of molecular markers with those expressed in the kidneys of lupus patients suggests potential new biomarkers and therapeutic targets.