bluuebunny/crossref_metadata_2025 huggingface dataset:
Anisotropy of magnetic susceptibility in natural olivine single crystals
Authors: Biedermann Andrea R. , Pettke Thomas , Reusser Eric , Hirt Ann M.
Published: July 2014

Mantle flow dynamics can cause preferential alignment of olivine crystals that results in anisotropy of physical properties. To interpret anisotropy in mantle rocks, it is necessary to understand the anisotropy of olivine single crystals. We determined anisotropy of magnetic susceptibility (AMS) for natural olivine crystals. High‐field AMS allows for the isolation of the anisotropy due to olivine alone. The orientations of the principal susceptibility axes are related to the olivine's crystallographic structure as soon as it contains >3 wt % FeO. The maximum susceptibility is parallel to the c axis both at room temperature (RT) and at 77 K. The orientation of the minimum axis at RT depends on iron content; it is generally parallel to the a axis in crystals with 3–5 wt % FeO, and along b in samples with 6–10 wt % FeO. The AMS ellipsoid is prolate and the standard deviatoric susceptibility, k′, is on the order of 8*10−10 m3/kg for the samples with <1wt % FeO, and ranges from 3.1*10−9 m3/kg to 5.7*10−9 m3/kg for samples with 3–10 wt % FeO. At 77 K, the minimum susceptibility is along b, independent of iron content. The shape of the AMS ellipsoid is prolate for samples with <5 wt % FeO, but can be prolate or oblate for higher iron content. The degree of anisotropy increases at 77 K with p′77 = 7.1 ± 0.5. The results from this study will allow AMS fabrics to be used as a proxy for olivine texture in ultramafic rocks with high olivine content.
The role of wind in the near field and midfield of a river plume
Authors: Kakoulaki Georgia , MacDonald Daniel , Horner‐Devine Alexander R.
Published: July 2014

The role of wind in the near‐field and midfield regions of the Merrimack River plume is quantified using observations from surface drifters released near the river mouth during ebb tide in 2009, 2010, and 2011 under a range of wind and river discharge conditions. Comparison of momentum balance terms and analysis of plume trajectories suggests that the plume is sensitive to wind direction for wind speeds >4 m s−1 in all regions of the plume, including the near field, where wind influence has typically been considered second order. Intermediate ranges (4–12 km) were more strongly influenced by the wind than the near field (0–4 km). However, the influence of the instantaneous wind diminished farther from the mouth, presumably, due to the growing importance of longer time scale process (i.e., Ekman transport). The plume was less sensitive to cross‐shore winds than alongshore winds, particularly near the river mouth, where momentum dominates.
Gas emissions from five volcanoes in northern Chile and implications for the volatiles budget of the Central Volcanic Zone
Authors: Tamburello G. , Hansteen T. H. , Bredemeyer S. , Aiuppa A. , Tassi F.
Published: July 2014

This study performed the first assessment of the volcanic gas output from the Central Volcanic Zone (CVZ) of northern Chile. We present the fluxes and compositions of volcanic gases (H2O, CO2, H2, HCl, HF, and HBr) from five of the most actively degassing volcanoes in this region—Láscar, Lastarria, Putana, Ollagüe, and San Pedro—obtained during field campaigns in 2012 and 2013. The inferred gas plume compositions for Láscar and Lastarria (CO2/Stot = 0.9–2.2; Stot/HCl = 1.4–3.4) are similar to those obtained in the Southern Volcanic Zone of Chile, suggesting uniform magmatic gas fingerprint throughout the Chilean arc. Combining these compositions with our own UV spectroscopy measurements of the SO2 output (summing to ~1800 t d−1 for the CVZ), we calculate a cumulative CO2 output of 1743–1988 t d−1 and a total volatiles output of >20,200 t d−1.
The precipitation of keV energetic oxygen ions at Mars and their effects during the comet Siding Spring approach
Authors: Gronoff Guillaume , Rahmati Ali , Wedlund Cyril Simon , Mertens Christopher J. , Cravens Thomas E. , Kallio Esa
Published: July 2014

Comet Siding Spring C/2013 A1 will pass Mars on 19 October 2014, entailing particle and dust precipitation in the Martian upper atmosphere and a potential dust hazard for orbiters. An estimate of the flux of energetic O+ ions picked up by the solar wind from the cometary coma is shown, with an increase of the O+ flux above 50 keV by 2 orders of magnitude. While the ionization of Mars' upper atmosphere by precipitating O+ ions is expected to be negligible compared to solar EUV‐XUV ionization, it is of the same order of magnitude at 110 km altitude during the cometary passage, leading to detectable increases in ionospheric densities. Cometary O+ pickup ion precipitation is expected to be the major nightside ionization source, creating a temporary ionosphere and a global airglow. These effects are dependent on the solar and cometary activities at the time of the encounter.
Simulation of substorm‐time acceleration of oxygen ions on azimuthally directed magnetic field lines in the near‐Earth plasma sheet
Authors: Nakayama Y. , Ebihara Y. , Tanaka T.
Published: July 2014

Acceleration of energetic ions is one of the drastic and common phenomena in the near‐Earth plasma sheet during the expansion phase of substorms. When a magnetic field line is stretched, the curvature radius of the magnetic field line becomes small, and many of energetic ions are accelerated nonadiabatically under the presence of electric fields. In a global magnetohydrodynamics (MHD) simulation, when the magnetic field line is further stretched, a flux rope structure appears in the near‐Earth plasma sheet (at ~8.5 RE for this particular simulation) for about 10 min before a substorm onset under the presence of the Y component of the interplanetary magnetic field. The magnetic field lines are azimuthally (in the east‐west direction) elongated near the equatorial plane, and the structure is different from that directly associated with magnetic reconnection. Based on a test particle simulation, we show that the oxygen ions departing in the flux rope structure a few minutes before the onset go around in the near‐Earth plasma sheet twice, experience strong dawn‐dusk electric field, and the ions gain kinetic energy as high as ~200 keV in ~10 min. The large acceleration results from nonadiabation motion together with geometry of magnetic field lines having a kink. The acceleration process (passing through or near the kink and energization by dawn‐dusk electric field) is not common. However, most of the particles that are accelerated more than 150 keV passed through or near the kink. The azimuthally elongated magnetic field line seems to have a large influence of substorm‐time acceleration of the oxygen ions that preexist before the onset.
The magnetic structure of Saturn's magnetosheath
Authors: Sulaiman A. H. , Masters A. , Dougherty M. K. , Jia X.
Published: July 2014

A planet's magnetosheath extends from downstream of its bow shock up to the magnetopause, where the solar wind flow is deflected around the magnetosphere and the solar wind‐embedded magnetic field lines are draped. This makes the region an important site for plasma turbulence, instabilities, reconnection, and plasma depletion layers. A relatively high Alfvén Mach number solar wind and a polar‐flattened magnetosphere make the magnetosheath of Saturn both physically and geometrically distinct from the Earth's. The polar flattening is predicted to affect the magnetosheath magnetic field structure and thus the solar wind‐magnetosphere interaction. Here we investigate the magnetic field in the magnetosheath with the expectation that polar flattening is manifested in the overall draping pattern. We compare an accumulation of Cassini data between 2004 and 2010 with global magnetohydrodynamic (MHD) simulations and an analytical model representative of a draped field between axisymmetric boundaries. The draping patterns measured are well captured and in broad agreement for given upstream conditions with those of the MHD simulations (which include polar flattening). The deviations from the analytical model, based on no polar flattening, suggest that nonaxisymmetry is invariably a key feature of the magnetosphere's global structure. Our results show a comprehensive overview of the configuration of the magnetic field in a nonaxisymmetric magnetosheath as revealed by Cassini. We anticipate our assessment to provide an insight to this barely studied interface between a high Alfvénic bow shock and a dynamic magnetosphere.
The role of ion‐molecule reactions in the growth of heavy ions in Titan's ionosphere
Authors: Westlake J. H. , Waite J. H. , Carrasco N. , Richard M. , Cravens T.
Published: July 2014

The Ion and Neutral Mass Spectrometer (INMS) and Cassini Plasma Spectrometer (CAPS) have observed Titan's ionospheric composition and structure over several targeted flybys. In this work we study the altitude profiles of the heavy ion population observed by the Cassini Plasma Spectrometer‐Ion Beam Spectrometer (CAPS‐IBS) during the nightside T57 flyby. We produce altitude profiles of heavy ions from the C6–C13 group (Ci indicates the number, i, of heavy atoms in the molecule) using a CAPS‐IBS/INMS cross calibration. These altitude profiles reveal structure that indicates a region of initial formation and growth at altitudes below 1200 km followed by a stagnation and dropoff at the lowest altitudes (1050 km). We suggest that an ion‐molecule reaction pathway could be responsible for the production of the heavy ions, namely reactions that utilize abundant building blocks such as C2H2 and C2H4, which have been shown to be energetically favorable and that have already been identified as ion growth patterns for the lighter ions detected by the INMS. We contrast this growth scenario with alternative growth scenarios determining the implications for the densities of the source heavy neutrals in each scenario. We show that the high‐mass ion density profiles are consistent with ion‐molecule reactions as the primary mechanism for large ion growth. We derive a production rate for benzene from electron recombination of C6H7+ of 2.4 × 10−16 g cm−2 s−1 and a total production rate for large molecules of 7.1 × 10−16 g cm−2 s−1.
Coastal cape and canyon effects on wind‐driven upwelling in northern Taiwan Strait
Authors: Chen Zhaoyun , Yan Xiao‐Hai , Jiang Yuwu
Published: July 2014

A combination of observations and numerical model is used to reveal the upwelling features and mechanisms in the northern Taiwan Strait during summer. In situ data give evidence of the upwelling in the form of thermocline tilting upward onshore. The remote sensing data show a strip of upwelling in the coastal region, which occurs more than half a summer. The upwelling probability map indicates there are two upwelling cores, one located downstream of Pingtan Island formed as cape effect and the other over the coastal canyon off the Sansha Bay. Remote sensing data and numerical model results suggest that the southerly wind plays a key role in shaping this upwelling strip, while the tides regulate the upwelling location through tidal mixing effect in the shallow water region, especially lee of Pingtan Island. Further numerical experiments using idealized cape and coastal canyon topography show that vertical velocity is intensified downstream of the cape and canyon. The vorticity equation shows that relative vorticity change along a streamline and frictional diffusion of vorticity are responsible for the vertical velocity off the cape and within and around the canyon. According to the conservation of potential vorticity, the variation of relative vorticity along a streamline over irregular topography, e.g., cape and canyon, is the main mechanism for the two upwelling cores in the northern Taiwan Strait.
New statistical analysis of the horizontal phase velocity distribution of gravity waves observed by airglow imaging
Authors: Matsuda Takashi S. , Nakamura Takuji , Ejiri Mitsumu K. , Tsutsumi Masaki , Shiokawa Kazuo
Published: July 2014

We have developed a new analysis method for obtaining the power spectrum in the horizontal phase velocity domain from airglow intensity image data to study atmospheric gravity waves. This method can deal with extensive amounts of imaging data obtained on different years and at various observation sites without bias caused by different event extraction criteria for the person processing the data. The new method was applied to sodium airglow data obtained in 2011 at Syowa Station (69°S, 40°E), Antarctica. The results were compared with those obtained from a conventional event analysis in which the phase fronts were traced manually in order to estimate horizontal characteristics, such as wavelengths, phase velocities, and wave periods. The horizontal phase velocity of each wave event in the airglow images corresponded closely to a peak in the spectrum. The statistical results of spectral analysis showed an eastward offset of the horizontal phase velocity distribution. This could be interpreted as the existence of wave sources around the stratospheric eastward jet. Similar zonal anisotropy was also seen in the horizontal phase velocity distribution of the gravity waves by the event analysis. Both methods produce similar statistical results about directionality of atmospheric gravity waves. Galactic contamination of the spectrum was examined by calculating the apparent velocity of the stars and found to be limited for phase speeds lower than 30 m/s. In conclusion, our new method is suitable for deriving the horizontal phase velocity characteristics of atmospheric gravity waves from an extensive amount of imaging data.
Ash mists and brown snow: Remobilization of volcanic ash from recent Icelandic eruptions
Authors: Liu E. J. , Cashman K. V. , Beckett F. M. , Witham C. S. , Leadbetter S. J. , Hort M. C. , Guðmundsson S.
Published: July 2014

Recent eruptions in Iceland and Chile have demonstrated that volcanic ash problems persist long after an eruption. For this reason, ash dispersion models are being extended to include ash remobilization. Critical to these models is knowledge of the ash source and the particle sizes that can be mobilized under different wind and moisture conditions. Here we characterize the physical and chemical characteristics of ash deposited on new snow in Reykjavík, Iceland, following a blizzard on 6 March 2013. Morphological, textural, and compositional analyses indicate resuspension from multiple eruptive deposits, including both Grímsvötn (2011) and Eyjafjallajökull (2010) eruptions. Grain size measurements show a mode of 32–63 µm, with particles as large as 177 µm; there is little mass in the very fine fraction, ≤10 µm (PM10). We compare our observations to predictions using the Lagrangian particle dispersion model, NAME (UK Met Office). The model output is consistent with observations in that it forecasts resuspension from both Eyjafjallajökull and Grímsvötn source regions, and shows ash deposition coincident with the timing of observed deposition in Reykjavík. The modeled deposit in Reykjavík predicts, however, a substantially lower proportion of Grímsvötn ash than observed. This discrepancy has highlighted the need to reassess the assumptions used in the simulations, particularly regarding the source area and precipitation thresholds. Furthermore, we suggest that modification of ash deposits in the form of erosion, redeposition, compaction, or cementation may influence the dynamics of resuspension over time, thus influencing the ability of model simulations to accurately forecast remobilization events.
A quick gap filling of missing hydrometeorological data
Authors: Pappas Christoforos , Papalexiou Simon Michael , Koutsoyiannis Demetris
Published: July 2014

Data gaps are ubiquitous in hydrometeorological time series, and filling these values still remains a challenge. Since data sets without missing values may be a prerequisite in performing many analyses, a quick and efficient gap‐filling methodology is required. In this study the problem of filling sporadic, single‐value gaps using time‐adjacent observations from the same location is investigated. The applicability of a local average (i.e., based on few neighboring in time observations) is examined and its advantages over the sample average (i.e., using the whole data set) are illustrated. The analysis reveals that a quick and very efficient (i.e., minimum mean‐squared estimation error) gap filling is achieved by combining a strictly local average (i.e., using one observation before and one after the missing value) with the sample mean.
The QBO in two GISS global climate models: 1. Generation of the QBO
Authors: Rind D. , Jonas J. , Balachandran N. K. , Schmidt G. A. , Lean J.
Published: July 2014

The adjustment of parameterized gravity waves associated with model convection and finer vertical resolution has made possible the generation of the quasi‐biennial oscillation (QBO) in two Goddard Institute for Space Studies (GISS) models, GISS Middle Atmosphere Global Climate Model III and a climate/middle atmosphere version of Model E2. Both extend from the surface to 0.002 hPa, with 2° × 2.5° resolution and 102 layers. Many realistic features of the QBO are simulated, including magnitude and variability of its period and amplitude. The period itself is affected by the magnitude of parameterized convective gravity wave momentum fluxes and interactive ozone (which also affects the QBO amplitude and variability), among other forcings. Although varying sea surface temperatures affect the parameterized momentum fluxes, neither aspect is responsible for the modeled variation in QBO period. Both the parameterized and resolved waves act to produce the respective easterly and westerly wind descent, although their effect is offset in altitude at each level. The modeled and observed QBO influences on tracers in the stratosphere, such as ozone, methane, and water vapor are also discussed. Due to the link between the gravity wave parameterization and the models' convection, and the dependence on the ozone field, the models may also be used to investigate how the QBO may vary with climate change.
Downscaling with a nested regional climate model in near‐surface fields over the contiguous United States
Authors: Wang Jiali , Kotamarthi Veerabhadra R.
Published: July 2014

The Weather Research and Forecasting (WRF) model is used for dynamic downscaling of 2.5‐degree National Centers for Environmental Prediction‐U.S. Department of Energy Reanalysis II (NCEP‐R2) data for 1980–2010 at 12 km resolution over most of North America. The model's performance for surface air temperature and precipitation is evaluated by comparison with high‐resolution observational data sets. The model's ability to add value is investigated by comparison with NCEP‐R2 data and a 50 km regional climate simulation. The causes for major model bias are studied through additional sensitivity experiments with various model setup/integration approaches and physics representations. The WRF captures the main features of the spatial patterns and annual cycles of air temperature and precipitation over most of the contiguous United States. However, simulated air temperatures over the south central region and precipitation over the Great Plains and the Southwest have significant biases. Allowing longer spin‐up time, reducing the nudging strength, or replacing the WRF Single‐Moment six‐class microphysics with Morrison microphysics reduces the bias over some subregions. However, replacing the Grell‐Devenyi cumulus parameterization with Kain‐Fritsch shows no improvement. The 12 km simulation does add value above the NCEP‐R2 data and the 50 km simulation over mountainous and coastal zones.
The life cycle of instability features measured from the Andes Lidar Observatory over Cerro Pachon on 24 March 2012
Authors: Hecht J. H. , Wan K. , Gelinas L. J. , Fritts D. C. , Walterscheid R. L. , Rudy R. J. , Liu A. Z. , Franke S. J. , Vargas F. A. , Pautet P. D. , Taylor M. J. , Swenson G. R.
Published: July 2014

The Aerospace Corporation's Nightglow Imager (ANI) observes nighttime OH emission (near 1.6 μm) every 2 s over an approximate 73° field of view. ANI had previously been used to study instability features seen over Maui. Here we describe observations of instabilities seen from 5 to 8 UT on 24 March 2012 over Cerro Pachon, Chile, and compare them with previous results from Maui, with theory, and with Direct Numerical Simulations (DNS). The atmosphere had reduced stability because of the large negative temperature gradients measured by a Na lidar. Thus, regions of dynamical and convective instabilities are expected to form, depending on the value of the Richardson number. Bright primary instabilities are formed with a horizontal wavelength near 9 km and showed the subsequent formation of secondary instabilities, rarely seen over Maui, consistent with the primaries being dynamical instabilities. The ratio of the primary to secondary horizontal wavelength was greater over Chile than over Maui. After dissipation of the instabilities, smaller‐scale features appeared with sizes in the buoyancy subrange between 1.5 and 6 km. Their size spectra were consistent with the model of Weinstock (1978) if the turbulence is considered to be increasing. The DNS results produce secondary instabilities with sizes comparable to what is seen in the images although their spectra are somewhat steeper than is observed. However, the DNS results also show that after the complete decay of the primary features, scale sizes considerably smaller than 1 km are produced and these cannot be seen by the ANI instrument.
Highly Efficient Simple‐Structure Blue and All‐Phosphor Warm‐White Phosphorescent Organic Light‐Emitting Diodes Enabled by Wide‐Bandgap Tetraarylsilane‐Based Functional Materials
Authors: Gong Shaolong , Sun Ning , Luo Jiajia , Zhong Cheng , Ma Dongge , Qin Jingui , Yang Chuluo
Published: July 2014

Two host materials of {4‐[diphenyl(4‐pyridin‐3‐ylphenyl)silyl]phenyl}diphenylamine (p‐PySiTPA) and {4‐[[4‐(diphenylphosphoryl)phenyl](diphenyl)silyl]phenyl}diphenylamine (p‐POSiTPA), and an electron‐transporting material of [(diphenylsilanediyl)bis(4,1‐phenylene)]bis(diphenylphosphine) dioxide (SiDPO) are developed by incorporating appropriate charge transporting units into the tetraarylsilane skeleton. The host materials feature both high triplet energies (ca. 2.93 eV) and ambipolar charge transporting nature; the electron‐transporting material comprising diphenylphosphine oxide units and tetraphenylsilane skeleton exhibits a high triplet energy (3.21 eV) and a deep highest occupied molecular orbital (HOMO) level (‐6.47 eV). Using these tetraarylsilane‐based functional materials results in a high‐efficiency blue phosphorescent device with a three‐organic‐layer structure of 1,1‐bis[4‐[N,N‐di(p‐tolyl)‐amino]phenyl]cyclohexane (TAPC)/p‐POSiTPA: iridium(III) bis(4′,6′‐difluorophenylpyridinato)tetrakis(1‐pyrazolyl)borate (FIr6)/SiDPO that exhibits a forward‐viewing maximum external quantum efficiency (EQE) up to 22.2%. This is the first report of three‐organic‐layer FIr6‐based blue PhOLEDs with the forward‐viewing EQE over 20%, and the device performance is among the highest for FIr6‐based blue PhOLEDs even compared with the four or more than four organic‐layer devices. Furthermore, with the introduction of bis(2‐(9,9‐diethyl‐9H‐fluoren‐2‐yl)‐1‐phenyl‐1H‐benzoimidazol‐N,C3)iridium acetylacetonate [(fbi)2Ir(acac)] as an orange emitter, an all‐phosphor warm‐white PhOLED achieves a peak power efficiency of 47.2 lm W−1, which is close to the highest values ever reported for two‐color white PhOLEDs.
A High Power Density Intermediate‐Temperature Solid Oxide Fuel Cell with Thin (La0.9Sr0.1)0.98(Ga0.8Mg0.2)O3‐δ Electrolyte and Nano‐Scale Anode
Authors: Gao Zhan , Miller Elizabeth C. , Barnett Scott A.
Published: July 2014

Solid oxide fuel cells (SOFCs) with thin (La0.9Sr0.1)0.98Ga0.8Mg0.2O3‐δ (LSGM) electrolytes are primary candidates for achieving high (> 1 W cm‐2) power density at intermediate (< 650 °C) temperatures. Although high power density LSGM‐electrolyte SOFCs have been reported, it is still necessary to develop a fabrication process suitable for large‐scale manufacturing and to minimize the amount of LSGM used. Here we show that SOFCs made with a novel processing method and a Sr0.8La0.2TiO3‐α (SLT) oxide support can achieve high power density at intermediate temperature. The SLT support is advantageous, especially compared to LSGM supports, because of its low materials cost, electronic conductivity, and good mechanical strength. The novel process is to first co‐fire the ceramic layers – porous SLT support, porous LSGM layer, and dense LSGM layer – followed by infiltration of nano‐scale Ni into the porous layers. Low polarization resistance of 0.188 Ωcm2 was achieved at 650 °C for a cell with an optimized anode functional layer (AFL) and an (La,Sr)(Fe,Co)O3 cathode. Maximum power density reached 1.12 W cm−2 at 650 °C, limited primarily by cathode polarization and ohmic resistances, so there is considerable potential to further improve the power density.
Enhancing Photovoltaic Performance Using an All‐Conjugated Random Copolymer to Tailor Bulk and Interfacial Morphology of the P3HT:ICBA Active Layer
Authors: Li Anton , Amonoo Jojo , Huang Bingyuan , Goldberg Peter K. , McNeil Anne J. , Green Peter F.
Published: July 2014

Bulk heterojunction (BHJ) solar cells are fabricated using active material blends of poly(3‐hexylthiophene) (P3HT) donor, indene‐C60 bisadduct (ICBA) acceptor, and an all‐conjugated random copolymer (RCP) additive. By optimizing RCP loading, power conversion efficiencies (PCEs) up to 20% higher than those of a binary P3HT:ICBA mixture are achieved. The improved device characteristics are rationalized in terms of the differences between the photoactive thin film morphologies. Energy‐filtered transmission electron micro­scopy reveals that incorporation of the RCP improves the degree of structural order of the BHJ fibrillar network and increases the extent of microphase separation between P3HT and ICBA. Additionally, a combination of atomic force microscopy and X‐ray photoelectron spectroscopy analysis indicates segregation of the RCP at the free interface, leading to a shift in the surface potentials measured by Kelvin probe force microscopy. These changes, both in the bulk morphology and in the interfacial composition/energetics, are correlated to improved carrier collection efficiency due to a reduction of non‐geminate recombination, which is measured by charge extraction of photo­generated carriers by linearly increasing voltage.
Porous Cu(I) Triazolate Framework and Derived Hybrid Membrane with Exceptionally High Sensing Efficiency for Gaseous Oxygen
Authors: Liu Si‐Yang , Qi Xiao‐Lin , Lin Rui‐Biao , Cheng Xiao‐Ning , Liao Pei‐Qin , Zhang Jie‐Peng , Chen Xiao‐Ming
Published: July 2014

Phosphorescent complexes of precious metal ions are widely studied as optical sensing materials for molecular oxygen. Combining the advantages of luminescent complexes and porous matrixes, porous coordination polymers show great potential for oxygen‐sensing, although their sensitivity, requirement of precious metal, and device fabrication remain challenging issues. In this work, the photoluminescence and oxygen‐sensing properties of the porous Cu(I) triazolate framework [Cu(detz)] (MAF‐2, Hdetz = 3,5‐diethyl‐1,2,4‐trizole) is studied in detail, which shows high chemical stability in moisture and water, very long phosphorescent lifetime (116 μs) and large Stokes shift (14 562 cm−1), as well as considerable oxygen permeability (1.7 × 10−11 mol cm−1 s−1 bar−1) at ambient conditions, giving rise to exceptionally high luminescence quenching efficiency of 99.7% at 1 bar O2 (I
0/I
100 = 356) with a perfectly linear Stern‐Volmer plot (K
SV = 356 bar−1, R
2 = 0.9998), fast response and good reversibility. Further, a counter‐diffusion crystal‐growth method was developed to fabricate MAF‐2 thin films protected by silicone rubbers as the first example of soft membrane oxygen sensor based on coordination polymer or metal‐organic framework, which exhibited extraordinary oxygen‐sensing performance (limit of detection = 0.047 mbar) and outstanding mechanical property, as well as outstanding chemical stability even in an acidic atmosphere.
One‐Step Hydrothermal Synthesis of 2D Hexagonal Nanoplates of α‐Fe2O3/Graphene Composites with Enhanced Photocatalytic Activity
Authors: Han Sancan , Hu Linfeng , Liang Ziqi , Wageh Swelm , Al‐Ghamdi Ahmed A. , Chen Yongsheng , Fang Xiaosheng
Published: July 2014

There has been significant progress in the field of semiconductor photocatalysis, but it is still a challenge to fabricate low‐cost and high‐activity photocatalysts because of safety issues and non‐secondary pollution to the environment. Here, 2D hexagonal nanoplates of α‐Fe2O3/graphene composites with relatively good distribution are synthesized for the first time using a simple, one‐step, template‐free, hydrothermal method that achieves the effective reduction of the graphene oxide (GO) to graphene and intimate and large contact interfaces of the α‐Fe2O3 nanoplates with graphene. The α‐Fe2O3/graphene composites showed significantly enhancement in the photocatalytic activity compared with the pure α‐Fe2O3 nanoplates. At an optimal ratio of 5 wt% graphene, 98% of Rhodamine (RhB) is decomposed with 20 min of irradiation, and the rate constant of the composites is almost four times higher than that of pure α‐Fe2O3 nanoplates. The decisive factors in improving the photocatalytic performance are the intimate and large contact interfaces between 2D hexagonal α‐Fe2O3 nanoplates and graphene, in addition to the high electron withdrawing/storing ability and the highconductivity of reduced graphene oxide (RGO) formed during the hydrothermal reaction. The effective charge transfer from α‐Fe2O3 nanoplates to graphene sheets is demonstrated by the significant weakening of photoluminescence in α‐Fe2O3/graphene composites.
Direct Observation of Conversion Between Threshold Switching and Memory Switching Induced by Conductive Filament Morphology
Authors: Sun Haitao , Liu Qi , Li Congfei , Long Shibing , Lv Hangbing , Bi Chong , Huo Zongliang , Li Ling , Liu Ming
Published: July 2014

Volatile threshold switching (TS) and non‐volatile memory switching (MS) are two typical resistive switching (RS) phenomena in oxides, which could form the basis for memory, analog circuits, and neuromorphic applications. Interestingly, TS and MS can be coexistent and converted in a single device under the suitable external excitation. However, the origin of the transition from TS to MS is still unclear due to the lack of direct experimental evidence. Here, conversion between TS and MS induced by conductive filament (CF) morphology in Ag/SiO2/Pt device is directly observed using scanning electron microscopy and high‐resolution transmission electron microscopy. The MS mechanism is related to the formation and dissolution of CF consisting of continuous Ag nanocrystals. The TS originates from discontinuous CF with isolated Ag nanocrystals. The results of current–voltage fitting and Kelvin probe force microscopy further indicate that the TS mechanism is related to the modulation of the tunneling barrier between Ag nanocrystals in CF. This work provides clearly experimental evidence to deepen understanding of the mechanism for RS in oxide‐electrolyte‐based resistive switching memory, contributing to better control of the two RS behaviors to establish high‐performance emerging devices.
First‐line treatment of 102 chronic myeloid leukemia patients with imatinib: A long‐term single institution analysis
Authors: Viganò Ilaria , Di Giacomo Nunzio , Bozzani Sofia , Antolini Laura , Piazza Rocco , Gambacorti Passerini Carlo
Published: July 2014

Imatinib mesylate radically changed the natural history of chronic myeloid leukemia (CML). The recent availability of alternative tyrosine kinase inhibitors (TKIs) renders the clinical management of CML more complex. In this article, we summarize our long‐term single institution experience. From 2003 to 2012, 102 patients with newly diagnosed chronic phase CML were referred to our institution and treated with imatinib mesylate as first‐line therapy. All patients were followed inside a dedicated CML clinic. At 1 year, 82/95 patients (86.3%) achieved complete cytogenetic response (CCyR) using a treatment performed analysis (TPA); when using an intention to treat analysis, 85/102 patients (83.3%) obtained CCyR. At 3 months, 58 patients (64.4% TPA) obtained a BCR‐ABL transcripts level <10%. A major molecular response (MMR) was obtained by 38% and 53% of patients at 1 and 2 years. Twenty patients (19.6%) discontinued treatment with imatinib; six of them did so in the initial 2 years of treatment (4 for resistance and 2 for adverse events). We observed seven deaths (6.86%). Overall survival (OS) at 6 years is 95.1% (95% C.I. 90–100%) and is not different from that of the general population. No patient experienced progression of disease (95% C.I.: 0–3%). Our results suggest that patient management is a crucial point to obtain a successful therapeutic outcome: at 1 year CCyR and MMR rates are similar to the results obtained with second generation TKIs and OS is not different from that of the general population.Am. J. Hematol. 89:E184–E187, 2014. © 2014 Wiley Periodicals, Inc.
Exploiting pre‐rRNA processing in Diamond Blackfan anemia gene discovery and diagnosis
Authors: Farrar Jason E. , Quarello Paola , Fisher Ross , O'Brien Kelly A. , Aspesi Anna , Parrella Sara , Henson Adrianna L. , Seidel Nancy E. , Atsidaftos Eva , Prakash Supraja , Bari Shahla , Garelli Emanuela , Arceci Robert J. , Dianzani Irma , Ramenghi Ugo , Vlachos Adrianna , Lipton Jeffrey M. , Bodine David M. , Ellis Steven R.
Published: July 2014

Diamond Blackfan anemia (DBA), a syndrome primarily characterized by anemia and physical abnormalities, is one among a group of related inherited bone marrow failure syndromes (IBMFS) which share overlapping clinical features. Heterozygous mutations or single‐copy deletions have been identified in 12 ribosomal protein genes in approximately 60% of DBA cases, with the genetic etiology unexplained in most remaining patients. Unlike many IBMFS, for which functional screening assays complement clinical and genetic findings, suspected DBA in the absence of typical alterations of the known genes must frequently be diagnosed after exclusion of other IBMFS. We report here a novel deletion in a child that presented such a diagnostic challenge and prompted development of a novel functional assay that can assist in the diagnosis of a significant fraction of patients with DBA. The ribosomal proteins affected in DBA are required for pre‐rRNA processing, a process which can be interrogated to monitor steps in the maturation of 40S and 60S ribosomal subunits. In contrast to prior methods used to assess pre‐rRNA processing, the assay reported here, based on capillary electrophoresis measurement of the maturation of rRNA in pre‐60S ribosomal subunits, would be readily amenable to use in diagnostic laboratories. In addition to utility as a diagnostic tool, we applied this technique to gene discovery in DBA, resulting in the identification of RPL31 as a novel DBA gene. Am. J. Hematol. 89:985–991, 2014. © 2014 Wiley Periodicals, Inc.
Prenatal diagnosis of CLOVES syndrome confirmed by detection of a mosaic PIK3CA mutation in cultured amniocytes
Authors: Emrick Lisa T. , Murphy Lauren , Shamshirsaz Alireza A. , Ruano Rodrigo , Cassady Christopher I. , Liu Liu , Chang Fengqi , Sutton V. Reid , Li Marilyn , Van den Veyver Ignatia B.
Published: July 2014

Congenital lipomatous asymmetric overgrowth of the trunk, lymphatic, capillary, venous, and combined‐type vascular malformations, epidermal nevi, skeletal and spinal anomalies (CLOVES) syndrome, a segmental overgrowth syndrome, is caused by post zygotic somatic mutations in PIK3CA, a gene involved in the receptor tyrosine kinase phosphatidylinositol 3‐kinase (PI3)‐AKT growth‐signaling pathway. Prenatal ultrasound findings of lymphovascular malformations, segmental overgrowth and skeletal defects can raise suspicion for CLOVES syndrome, but molecular confirmation of PIK3CA mutations on prenatally obtained samples is challenging because of somatic mosaicism. We detected a mosaic disease‐causing mutation in PIK3CA by sequencing of DNA extracted from cultured amniotic cells, but not from DNA directly prepared from an amniotic fluid sample in a fetus with prenatally suspected CLOVES syndrome. The infant was born prematurely and displayed severe lymphovascular malformations and segmental overgrowth consistent with a clinical diagnosis of CLOVES syndrome; he passed away at 29 days of life. We discuss the complexities and limitations of genetic testing for somatic mosaic mutations in the prenatal period and highlight the potential need for multiple approaches to arrive at a molecular diagnosis. © 2014 Wiley Periodicals, Inc.
A Ruthenium‐Based Light‐Harvesting Antenna Bearing an Anthracene Moiety in Dye‐Sensitized Solar Cells
Authors: Vougioukalakis Georgios C. , Konstantakou Maria , Pefkianakis Eleftherios K. , Kabanakis Antonios N. , Stergiopoulos Thomas , Kontos Athanassios G. , Andreopoulou Aikaterini K. , Kallitsis Joannis K. , Falaras Polycarpos
Published: July 2014

A heteroleptic ruthenium sensitizer (DV56) bearing a terpyridine ligand with an appended phenylanthracene moiety was synthesized and extensively characterized. The physicochemical properties of the light‐harvesting antenna were studied in solution and on sensitized TiO2 thin film electrodes using a variety of spectroscopic and photoelectrochemical techniques. Contact angle measurements suggest that the DV56‐sensitized TiO2 films are hydrophilic. Raman measurements indicate chemisorption of the dye on the semiconducting surface. Electrochemical studies of the dye show that its first oxidation potential lies well below the I−/I3− redox potential, allowing easy regeneration. Moreover, its excited state oxidation potential lies above the TiO2 conduction band edge, permitting efficient electron injection from the photosensitizer into the semiconductor. I−/I3−‐based liquid redox electrolyte dye‐sensitized solar cells incorporating DV56‐sensitized TiO2 photoelectrodes afford an overall power conversion efficiency of 3.75 %.
Relationship between systolic blood pressures measured in emergency department and outcomes in patients with subarachnoid hemorrhage
Authors: Inamasu Joji , Oheda Motoki , Ito Keisuke , Kato Yoko , Hirose Yuichi
Published: July 2014

Aim

High blood pressure is observed frequently in patients with subarachnoid hemorrhage who present to the emergency department. Although extremely high blood pressure is known to predict poor outcomes in patients with spontaneous intracerebral hemorrhage, the relationship between high blood pressure and outcomes has been studied less frequently in patients with subarachnoid hemorrhage.

Methods

A retrospective study was carried out to evaluate whether high blood pressure observed in the emergency department was predictive of poor outcomes in patients with subarachnoid hemorrhage. Three‐hundred and twelve subarachnoid hemorrhage patients who were admitted to our institution were quadrichotomized based on their initial systolic blood pressure: <140 mmHg (n = 60), 140–184 mmHg (n = 144), 185–219 mmHg (n = 64), and ≥220 mmHg (n = 44). Demographics including subarachnoid hemorrhage severity (World Federation of Neurosurgical Societies grade) and outcome variables evaluated with the modified Rankin scale 30 days after admission were compared among the four blood pressure groups. Furthermore, an effort was made to delineate a threshold value of systolic blood pressure predictive of outcomes by receiver operating characteristic curve analysis.

Results

The frequency of grade V subarachnoid hemorrhage in the ≥220 mmHg group (55%) was significantly higher than in the other three blood pressure groups. The frequency of patients scoring 5–6 on the modified Rankin scale in the ≥220 mmHg group (54%) was significantly higher than in the other three blood pressure groups. The cut‐off systolic blood pressure value predicting poor outcomes (modified Rankin scale 5–6) determined by receiver operating characteristic curve analysis was 189 mmHg.

Conclusions

The higher proportion of grade V patients may be responsible for the worse outcomes in the group with systolic blood pressure ≥220 mmHg. Initial systolic blood pressure ≥220 mmHg may be a crude indicator of poor outcomes in patients with subarachnoid hemorrhage.
Wechselwirkungen von Proteinen mit Polymerbeschichtungen und Biomaterialien
Authors: Wei Qiang , Becherer Tobias , Angioletti‐Uberti Stefano , Dzubiella Joachim , Wischke Christian , Neffe Axel T. , Lendlein Andreas , Ballauff Matthias , Haag Rainer
Published: July 2014

Die Proteinadsorption gilt als der wichtigste Faktor der Wechselwirkung zwischen polymeren Biomaterialien und Körperflüssigkeiten oder ‐gewebe. Die Haupteinflussfaktoren auf die Proteinadsorption sind wasservermittelte hydrophobe und Hydratationskräfte sowie elektrostatische Wechselwirkungen. Eine systematische Analyse verschiedener Monolagen führte zur Aufstellung allgemeiner Leitsätze, den sogenannten “Whitesides‐Regeln”. Diese Konzepte wurden erfolgreich auf die Entwicklung verschiedener proteinresistenter Oberflächen angewendet und werden kontinuierlich weiterentwickelt, um das Verständnis von Protein‐Material‐Wechselwirkungen über die bisherigen Grenzen hinaus zu erweitern. Ebenso werden die Theorien zu Proteinadsorptionsmechanismen aufgrund der sich schnell entwickelnden analytischen Technologien fortlaufend verbessert. Ziel dieses Aufsatzes ist die Verbesserung der aufgestellten empirischen Leitlinien im Hinblick auf die theoretischen und analytischen Fortschritte. Dabei werden die aktuellen analytischen Methoden zur Untersuchung mechanistischer Hypothesen und Theorien zu Protein‐Oberflächen‐Wechselwirkungen besprochen. Ein besonderes Augenmerk liegt auf aktuellen Technologien im Bereich bioinerter und biospezifischer Beschichtungen und ihrer Anwendungen in der Biomedizin.
Harnessing the Liquid‐Phase Exfoliation of Graphene Using Aliphatic Compounds: A Supramolecular Approach
Authors: Ciesielski Artur , Haar Sébastien , El Gemayel Mirella , Yang Huafeng , Clough Joseph , Melinte Georgian , Gobbi Marco , Orgiu Emanuele , Nardi Marco V. , Ligorio Giovanni , Palermo Vincenzo , Koch Norbert , Ersen Ovidiu , Casiraghi Cinzia , Samorì Paolo
Published: July 2014

The technological exploitation of the extraordinary properties of graphene relies on the ability to achieve full control over the production of a high‐quality material and its processing by up‐scalable approaches in order to fabricate large‐area films with single‐layer or a few atomic‐layer thickness, which might be integrated in working devices. A simple method is reported for producing homogenous dispersions of unfunctionalized and non‐oxidized graphene nanosheets in N‐methyl‐2‐pyrrolidone (NMP) by using simple molecular modules, which act as dispersion‐stabilizing compounds during the liquid‐phase exfoliation (LPE) process, leading to an increase in the concentration of graphene in dispersions. The LPE‐processed graphene dispersion was shown to be a conductive ink. This approach opens up new avenues for the technological applications of this graphene ink as low‐cost electrodes and conducting nanocomposite for electronics.
Funktionalisiertes Graphen als Türsteher für chirale Moleküle: ein alternatives Konzept zur Racematspaltung
Authors: Hauser Andreas W. , Mardirossian Narbe , Panetier Julien A. , Head‐Gordon Martin , Bell Alexis T. , Schwerdtfeger Peter
Published: July 2014

Ein neuartiges, auf funktionalisiertem, nanoporösen Graphen basierendes Verfahren zur Abtrennung chiraler Moleküle wird vorgestellt. Auf Dichtefunktionaltheorie basierende Computersimulationen zeigen, dass durch Anhaften eines chiralen “Türsteher”‐Moleküls an den Porenrand einer Form des Enantiomers der Eintritt verweigert wird, während sein Spiegelbild passieren kann.
A Conical Intersection Controls the Deactivation of the Bacterial Luciferase Fluorophore
Authors: Gozem Samer , Mirzakulova Ekaterina , Schapiro Igor , Melaccio Federico , Glusac Ksenija D. , Olivucci Massimo
Published: July 2014

The photophysics of flavins is highly dependent on their environment. For example, 4a‐hydroxy flavins display weak fluorescence in solution, but exhibit strong fluorescence when bound to a protein. To understand this behavior, we performed temperature‐dependent fluorescent studies on an N(5)‐alkylated 4a‐hydroxy flavin: the putative bacterial luciferase fluorophore. We find an increase in fluorescence quantum yield upon reaching the glass transition temperature of the solvent. We then employ multiconfigurational quantum chemical methods to map the excited‐state deactivation path of the system. The result reveals a shallow but barrierless excited state deactivation path that leads to a conical intersection displaying an orthogonal out‐of‐plane distortion of the terminal pyrimidine ring. The intersection structure readily explains the observed spectroscopic behavior in terms of an excited‐state barrier imposed by the rigid glass cavity.
Tailoring Intermolecular Interactions for Efficient Room‐Temperature Phosphorescence from Purely Organic Materials in Amorphous Polymer Matrices
Authors: Kwon Min Sang , Lee Dongwook , Seo Sungbaek , Jung Jaehun , Kim Jinsang
Published: July 2014

Herein we report a rational design strategy for tailoring intermolecular interactions to enhance room‐temperature phosphorescence from purely organic materials in amorphous matrices at ambient conditions. The built‐in strong halogen and hydrogen bonding between the newly developed phosphor G1 and the poly(vinyl alcohol) (PVA) matrix efficiently suppresses vibrational dissipation and thus enables bright room‐temperature phosphorescence (RTP) with quantum yields reaching 24 %. Furthermore, we found that modulation of the strength of halogen and hydrogen bonding in the G1–PVA system by water molecules produced unique reversible phosphorescence‐to‐fluorescence switching behavior. This unique system can be utilized as a ratiometric water sensor.
UV Excited‐State Photoresponse of Biochromophore Negative Ions
Authors: Bochenkova Anastasia V. , Klærke Benedikte , Rahbek Dennis B. , Rajput Jyoti , Toker Yoni , Andersen Lars H.
Published: July 2014

Members of the green fluorescent protein (GFP) family may undergo irreversible phototransformation upon irradiation with UV light. This provides clear evidence for the importance of the higher‐energy photophysics of the chromophore, which remains essentially unexplored. By using time‐resolved action and photoelectron spectroscopy together with high‐level electronic structure theory, we directly probe and identify higher electronically excited singlet states of the isolated para‐ and meta‐chromophore anions of GFP. These molecular resonances are found to serve as a doorway for very efficient electron detachment in the gas phase. Inside the protein, this band is found to be resonant with the quasicontinuum of a solvated electron, thus enhancing electron transfer from the GFP to the solvent. This suggests a photophysical pathway for photoconversion of the protein, where GFP resonant photooxidation in solution triggers radical redox reactions inside these proteins.
Self‐Healable Electrically Conducting Wires for Wearable Microelectronics
Authors: Sun Hao , You Xiao , Jiang Yishu , Guan Guozhen , Fang Xin , Deng Jue , Chen Peining , Luo Yongfeng , Peng Huisheng
Published: July 2014

Electrically conducting wires play a critical role in the advancement of modern electronics and in particular are an important key to the development of next‐generation wearable microelectronics. However, the thin conducting wires can easily break during use, and the whole device fails to function as a result. Herein, a new family of high‐performance conducting wires that can self‐heal after breaking has been developed by wrapping sheets of aligned carbon nanotubes around polymer fibers. The aligned carbon nanotubes offer an effective strategy for the self‐healing of the electric conductivity, whereas the polymer fiber recovers its mechanical strength. A self‐healable wire‐shaped supercapacitor fabricated from a wire electrode of this type maintained a high capacitance after breaking and self‐healing.