bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characteristics of tropopause‐penetrating convection determined by TRMM and COSMIC GPS radio occultation measurements
Authors: Xian Tao , Fu Yunfei 
Published: June 2015

AbstractDistribution and influence of convection in the upper troposphere and lower stratosphere have been investigated case by case or on regional to global scale. However, previous studies were limited by using proxies for convection or the bias of the tropopause data. Here the tropopause‐penetrating convection is investigated based on the sole use of observational products from Tropical Rainfall Measuring Mission (TRMM) precipitation radar data and Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC). The result shows that the frequency of precipitation‐top heights above the monthly mean tropopause in the tropics is reduced logarithmically if the cold‐point tropopause is adopted instead of the lapse‐rate tropopause. Using the collocated COSMIC and precipitation radar observations, the tropopause‐penetrating convection, i.e., the convection with the precipitation‐top height above the lapse‐rate tropopause, can be found over the summer monsoon regions and some continental regions. The averaged relative precipitation‐top heights of tropopause‐penetrating convective clusters are about 0.2–0.5 km without significant land‐ocean difference, while equivalent radii of clusters are 2.7–3.5 km over land and 0.2–0.5 km larger than those over ocean. These areal and vertical extents are smaller than those reported by previous studies. Furthermore, the collocated temperature profiles show that the tropopause‐penetrating convection generates warming in the upper troposphere and cooling near the lapse‐rate tropopause and in the lower stratosphere. Moreover, the tropopause‐penetrating convection leads to a rapid (within 20 min) lift of the lapse‐rate tropopause by the adiabatic lofting within the convection (within a 10 km radius).
Optimal antenna topologies for spatial gradient detection in differential GNSS
Authors: Jing Jing , Khanafseh Samer , Langel Steven , Chan Fang‐Cheng , Pervan Boris 
Published: June 2015

AbstractThis paper describes new methods to determine optimal reference antenna topologies for detection of spatial gradients in differential Global Navigation Satellite Systems (GNSS). Such gradients can be caused by ionospheric fronts and orbit ephemeris faults, and if undetected, represent major threats to aircraft navigation integrity. Differential carrier phase measurements between ground antennas are highly sensitive to spatial gradients. Therefore, monitors using spatially separated ground antennas have recently attracted great interest. However, they cannot detect gradients of all sizes and directions due to the presence of integer ambiguities. These ambiguities cannot be resolved because the gradient magnitude is unknown a priori. Furthermore, the performance of such monitors is highly dependent on the spatial distribution of reference antennas. In this work, we introduce new methods to find optimized antenna topologies for spatial gradient detection.
Thermal cell structures in the high‐latitude thermosphere induced by ion drag
Authors: Walterscheid R. L. , Crowley G. 
Published: June 2015

AbstractThe occurrence of high‐latitude thermospheric density structures during disturbed conditions that are more complex than the forcing itself suggests that the structure may be caused by a qualitative change in the balance of forces. Using a general circulation model of the thermosphere, we have examined the terms involved in the force balance for levels in the upper and lower thermosphere during active and quiet times and examined the thermal structure in relation to the terms that dominate the balance. A simulation reveals that where ion drag is unable to accelerate the atmosphere into rapid motion the Coriolis force dominates and for fixed pressure levels the centers of cyclonic motion are colder and denser than the surrounding air, while centers of anticyclonic motion are warmer and less dense. At fixed heights, densities are high in the evening anticyclonic gyre and low in the dawn cyclonic gyre. Another simulation reveals that this situation is radically changed when the atmosphere is spun up to rapid motion and the centrifugal force is the dominant inertial force, whence both anticyclones and cyclones become centers of relatively cold high‐density air at fixed pressure levels. On constant height surfaces, cold low‐density centers are found on both the dawnside and duskside with a trough of low‐density air over the pole connecting them. This intrusion of low‐density splits the evening high‐density region that exists under quiet conditions giving the four‐cell pattern found by Crowley et al. (1989a, 1996a, 1996b).
Simulation of polar ozone depletion: An update
Authors: Solomon Susan , Kinnison Doug , Bandoro Justin , Garcia Rolando 
Published: June 2015

AbstractWe evaluate polar ozone depletion chemistry using the specified dynamics version of the Whole Atmosphere Community Climate Model for the year 2011. We find that total ozone depletion in both hemispheres is dependent on cold temperatures (below 192 K) and associated heterogeneous chemistry on polar stratospheric cloud particles. Reactions limited to warmer temperatures above 192 K, or on binary liquid aerosols, yield little modeled polar ozone depletion in either hemisphere. An imposed factor of three enhancement in stratospheric sulfate increases ozone loss by up to 20 Dobson unit (DU) in the Antarctic and 15 DU in the Arctic in this model. Such enhanced sulfate loads are similar to those observed following recent relatively small volcanic eruptions since 2005 and imply impacts on the search for polar ozone recovery. Ozone losses are strongly sensitive to temperature, with a test case cooler by 2 K producing as much as 30 DU additional ozone loss in the Antarctic and 40 DU in the Arctic. A new finding of this paper is the use of the temporal behavior and variability of ClONO2 and HCl as indicators of the efficacy of heterogeneous chemistry. Transport of ClONO2 from the southern subpolar regions near 55–65°S to higher latitudes near 65–75°S provides a flux of NOx from more sunlit latitudes to the edge of the vortex and is important for ozone loss in this model. Comparisons between modeled and observed total column and profile ozone perturbations, ClONO2 abundances, and the rate of change of HCl bolster confidence in these conclusions.
Spatiotemporal patterns of terrestrial gross primary production: A review
Authors: Anav Alessandro , Friedlingstein Pierre , Beer Christian , Ciais Philippe , Harper Anna , Jones Chris , Murray‐Tortarolo Guillermo , Papale Dario , Parazoo Nicholas C. , Peylin Philippe , Piao Shilong , Sitch Stephen , Viovy Nicolas , Wiltshire Andy , Zhao Maosheng 
Published: June 2015

AbstractGreat advances have been made in the last decade in quantifying and understanding the spatiotemporal patterns of terrestrial gross primary production (GPP) with ground, atmospheric, and space observations. However, although global GPP estimates exist, each data set relies upon assumptions and none of the available data are based only on measurements. Consequently, there is no consensus on the global total GPP and large uncertainties exist in its benchmarking. The objective of this review is to assess how the different available data sets predict the spatiotemporal patterns of GPP, identify the differences among data sets, and highlight the main advantages/disadvantages of each data set. We compare GPP estimates for the historical period (1990–2009) from two observation‐based data sets (Model Tree Ensemble and Moderate Resolution Imaging Spectroradiometer) to coupled carbon‐climate models and terrestrial carbon cycle models from the Fifth Climate Model Intercomparison Project and TRENDY projects and to a new hybrid data set (CARBONES). Results show a large range in the mean global GPP estimates. The different data sets broadly agree on GPP seasonal cycle in terms of phasing, while there is still discrepancy on the amplitude. For interannual variability (IAV) and trends, there is a clear separation between the observation‐based data that show little IAV and trend, while the process‐based models have large GPP variability and significant trends. These results suggest that there is an urgent need to improve observation‐based data sets and develop carbon cycle modeling with processes that are currently treated either very simplistically to correctly estimate present GPP and better quantify the future uptake of carbon dioxide by the world's vegetation.
A numerical technique for two‐way radio occultations by oblate axisymmetric atmospheres with zonal winds
Authors: Schinder P. J. , Flasar F. M. , Marouf E. A. , French R. G. , Anabtawi A. , Barbinis E. , Kliore A. J. 
Published: June 2015

AbstractThe Ultra Stable Oscillator aboard the Cassini spacecraft failed in late 2011, which means that all radio occultations after that date have to be done in two‐way mode, using a ground‐based signal transmitted to the spacecraft as the frequency reference. Here we present the numerical technique we use to analyze the data from the two‐way atmospheric radio occultations of both Saturn and Titan that have occurred since the Ultra Stable Oscillator (USO) failure, along with the theoretical reasons behind this technique. Since our two‐way technique is based upon our earlier one‐way technique which used the USO as the frequency reference, we also present our one‐way technique which we used for Saturn occultations prior to the loss of the USO.
High‐resolution Far‐field Microscopy
Authors: Tolstik Elen , Shukla Sapna , Heintzmann Rainer 
Published: June 2015

AbstractThe developments in high‐resolution microscopy play a challenging role in understanding the fundamental processes in molecular and cell‐biology as well as material research. The most desired feature of any optical microscopy technique is the ability to perform in‐depth scanning of specimens and to distinguish extremely small organelles and their dynamics in the nanometer range. To answer a large variety of questions in all areas of biological and material research, it has become imperative to improve the spatial and temporal resolution of optical microscopes. However since the nineteenth century when Ernst Abbe first established the limit of an optical system to resolve two objects – the Abbe diffraction limit – the scientists have been struggling to approach nanometer resolution by defying the diffraction limit. These continued efforts have led to the development of novel super‐resolution technologies in microscopy that are discussed in this review.
Optical Coherence Tomography
Authors: Andersen Peter E. 
Published: June 2015

AbstractOptical coherence tomography (OCT) is a noninvasive imaging technique that provides real‐time two‐ and three‐dimensional images of scattering samples with micrometer resolution. Mapping the local reflectivity, OCT visualizes the morphology of the sample, in real time or at video rate. In addition, functional properties such as birefringence or blood flow may be detected and used for improved diagnosis. In ophthalmology, OCT is accepted as a clinical standard for diagnosing and monitoring the treatment of a wide range of retinal diseases. With increased image acquisition speed, real‐time or video‐rate imaging is feasible, which has enabled optical microangiography, i.e., visualization of retinal and chorodial blood flow. Such label‐free optical microangiography might be feasible as an adjunct modality to fluorescence‐based angiography. In this review, the fundamental principles of OCT imaging and its main functional extensions are introduced. The part is followed by a discussion of ophthalmic OCT. Finally potential emerging modalities are discussed briefly.
W
igner Function in Optics, The
Authors: Petruccelli Jonathan C. , Alonso Miguel A. 
Published: June 2015

Abstract
In this article, we provide a brief review of the use of the Wigner function in classical optics. Using this mathematical representation, the propagation of light beams through simple optical systems follows rules similar to those of ray optics. Similarly, when applied to optical pulses, the Wigner function allows a description of propagation through dispersive media in a way reminiscent of the propagation of an ensemble of classical particles.
Optical Angular Momentum
Authors: Forbes Andrew , McLaren Melanie 
Published: June 2015

AbstractThat light may possess optical angular momentum is a fact that has been known and exploited for over a hundred years. At first, it was entirely associated with the spin angular momentum of light, through light's polarization. More recently, the orbital angular momentum of light has been studied and exploited for a plethora of applications. This component is associated with the spatial profile of the field. This article outlines the basic concepts of spin and orbital angular momentum, their connectedness through vector beams, and Poincaré sphere representations of optical angular momentum carrying fields and reviews the present state of the field and its many opportunities for advancement.
Vier Jahrzehnte Chemie der planar hyperkoordinierten Verbindungen
Authors: Yang Li‐Ming , Ganz Eric , Chen Zhongfang , Wang Zhi‐Xiang , Schleyer Paul von Ragué 
Published: June 2015

AbstractPlanar vierfach koordinierter Kohlenstoff (ptC) wurde seit 1874 für über ein Jahrhundert als unplausibel angesehen. Danach konnten jedoch Beispiele rechnerisch vorhergesagt und experimentell realisiert werden. Sowohl elektronische als auch mechanische Effekte (z. B. in kleinen Ringen und Käfigen) stabilisieren diese ungewöhnlichen Bindungsanordnungen. Konzepte basierend auf den Bindungsmotiven des planaren Methans/planaren Methandikations können erweitert werden, um planar hyperkoordinierte Strukturen anderer chemischer Elemente zu entwerfen. Zahlreiche Konfigurationen von verschiedenen Zentralatomen (Haupt‐ und Übergangsmetallelementen) in einer Ebene mit Koordinationszahlen von bis zu zehn werden diskutiert. Die Evolution von solchen planaren Konfigurationen aus kleinen Molekülen zu Clustern, nanoskopischen Spezies bis hin zu Festkörpern wird aufgezeigt. Für einige experimentell hergestellte planare Materialien wurden außergewöhnliche elektrische und magnetische Eigenschaften nachgewiesen.
Direct Synthesis of Chiral Allenoates from the Asymmetric CH Insertion of α‐Diazoesters into Terminal Alkynes
Authors: Tang Yu , Chen Quangang , Liu Xiaohua , Wang Gang , Lin Lili , Feng Xiaoming 
Published: June 2015

AbstractThe asymmetric CH insertion of α‐diazoesters into 1‐alkynes was achieved using chiral cationic guanidinium salts and copper(I) complexes. Optically active 2,4‐disubstituted allenoates were generated under mild reaction conditions from various α‐diazoesters and 1‐alkynes in high yield (up to 99 %) and enantioselectivity (up to 97:3 e.r.). Control experiments excluded the possibility of an asymmetric isomerization of alkynoates.
Metallocorroles as Photocatalysts for Driving Endergonic Reactions, Exemplified by Bromide to Bromine Conversion
Authors: Mahammed Atif , Gross Zeev 
Published: June 2015

AbstractPhotochemical oxidation of halide anions by visible light has been suggested for solar energy conversion processes. Post‐transition metallocorroles are now disclosed as very efficient catalysts for the photoinduced transformation of bromide to bromine. The advantages of these catalysts are that they are very stable under the reaction conditions and that the energy levels of the oxidizing HOMO and the reducing LUMO are easily tuned. Insights into the mechanism of action obtained in this work is predicted to be very useful for the design of other systems that rely on photocatalysis for driving endergonic reactions.
Energy Storage Materials from Nature through Nanotechnology: A Sustainable Route from Reed Plants to a Silicon Anode for Lithium‐Ion Batteries
Authors: Liu Jun , Kopold Peter , van Aken Peter A. , Maier Joachim , Yu Yan 
Published: June 2015

AbstractSilicon is an attractive anode material in energy storage devices, as it has a ten times higher theoretical capacity than its state‐of‐art carbonaceous counterpart. However, the common process to synthesize silicon nanostructured electrodes is complex, costly, and energy‐intensive. Three‐dimensional (3D) porous silicon‐based anode materials have been fabricated from natural reed leaves by calcination and magnesiothermic reduction. This sustainable and highly abundant silica source allows for facile production of 3D porous silicon with very good electrochemical performance. The obtained silicon anode retains the 3D hierarchical architecture of the reed leaf. Impurity leaching and gas release during the fabrication process leads to an interconnected porosity and the reductive treatment to an inside carbon coating. Such anodes show a remarkable Li‐ion storage performance: even after 4000 cycles and at a rate of 10 C, a specific capacity of 420 mA h g−1 is achieved.
Controlled Anisotropic Growth of Co‐Fe‐P from Co‐Fe‐O Nanoparticles
Authors: Mendoza‐Garcia Adriana , Zhu Huiyuan , Yu Yongsheng , Li Qing , Zhou Lin , Su Dong , Kramer Matthew J. , Sun Shouheng 
Published: June 2015

AbstractA facile approach to bimetallic phosphides, Co‐Fe‐P, by a high‐temperature (300 °C) reaction between Co‐Fe‐O nanoparticles and trioctylphosphine is presented. The growth of Co‐Fe‐P from the Co‐Fe‐O is anisotropic. As a result, Co‐Fe‐P nanorods (from the polyhedral Co‐Fe‐O nanoparticles) and sea‐urchin‐like Co‐Fe‐P (from the cubic Co‐Fe‐O nanoparticles) are synthesized with both the nanorod and the sea‐urchin‐arm dimensions controlled by Co/Fe ratios. The Co‐Fe‐P structure, especially the sea‐urchin‐like (Co0.54Fe0.46)2P, shows enhanced catalysis for the oxygen evolution reaction in KOH with its catalytic efficiency surpassing the commercial Ir catalyst. Our synthesis is simple and may be readily extended to the preparation of other multimetallic phosphides for important catalysis and energy storage applications.
Reduktive Insertion von elementaren Chalkogenen in Bor‐Bor‐ Mehrfachbindungen
Authors: Braunschweig Holger , Dellermann Theresa , Ewing William C. , Kramer Thomas , Schneider Christoph , Ullrich Stefan 
Published: June 2015

AbstractDie Synthese schwefel‐ und selenverbrückender Ringsysteme, die durch N‐heterocyclische Carbene stabilisierte Boreinheiten enthalten, gelang durch reduktive Insertion von elementaren Chalkogenen in Bor‐Bor‐Mehrfachbindungen. Die drei bindenden Elektronenpaare zwischen den Boratomen eines Diborins ermöglichen eine Sechs‐Elektronen‐Reduktion und führen zur Bildung eines [2.2.1]‐Bicyclus, in welchem die Brückenkopf‐Boratome durch drei Chalkogenbrücken überspannt sind. Eine ähnliche Reaktion an einem Diboren (Bor‐Bor‐Doppelbindung) führt zu einer reduktiven Übertragung der beiden bindenden Elektronenpaare auf drei Schwefelatome unter Bildung eines NHC‐stabilisierten Trisulfidodiborolans. Der Nachweis dieser Sechs‐ bzw. Vier‐Elektronen‐Reduktionen stützt die Beschreibung von Diborenen bzw. Diborinen mit zwei bzw. drei bindenden Elektronenpaaren – eine Tatsache, die in zukünftigen Diskussionen zur Bindungsordnung nützlich sein könnte.
Integrating NiCo Alloys with Their Oxides as Efficient Bifunctional Cathode Catalysts for Rechargeable Zinc–Air Batteries
Authors: Liu Xien , Park Minjoon , Kim Min Gyu , Gupta Shiva , Wu Gang , Cho Jaephil 
Published: June 2015

AbstractThe lack of high‐efficient, low‐cost, and durable bifunctional electrocatalysts that act simultaneously for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) is currently one of the major obstacles to commercializing the electrical rechargeability of zinc–air batteries. A nanocomposite CoO‐NiO‐NiCo bifunctional electrocatalyst supported by nitrogen‐doped multiwall carbon nanotubes (NCNT/CoO‐NiO‐NiCo) exhibits excellent activity and stability for the ORR/OER in alkaline media. More importantly, real air cathodes made from the bifunctional NCNT/CoO‐NiO‐NiCo catalysts further demonstrated superior performance to state‐of‐the‐art Pt/C or Pt/C+IrO2 catalysts in primary and rechargeable zinc–air batteries.
Catalytic Stereoinversion of L‐Alanine to Deuterated D‐Alanine
Authors: Moozeh Kimia , So Soon Mog , Chin Jik 
Published: June 2015

AbstractA combination of an achiral pyridoxal analogue and a chiral base has been developed for catalytic deuteration of L‐alanine with inversion of stereochemistry to give deuterated D‐alanine under mild conditions (neutral pD and 25 °C) without the use of any protecting groups. This system can also be used for catalytic deuteration of D‐alanine with retention of stereochemistry to give deuterated D‐alanine. Thus a racemic mixture of alanine can be catalytically deuterated to give an enantiomeric excess of deuterated D‐alanine. While catalytic deracemization of alanine is forbidden by the second law of thermodynamics, this system can be used for catalytic deracemization of alanine with deuteration. Such green and biomimetic approach to catalytic stereocontrol provides insights into efficient amino acid transformations.
Influence of Guest Exchange on the Magnetization Dynamics of Dilanthanide Single‐Molecule‐Magnet Nodes within a Metal–Organic Framework
Authors: Zhang Xuejing , Vieru Veacheslav , Feng Xiaowen , Liu Jun‐Liang , Zhang Zhenjie , Na Bo , Shi Wei , Wang Bing‐Wu , Powell Annie K. , Chibotaru Liviu F. , Gao Song , Cheng Peng , Long Jeffrey R. 
Published: June 2015

AbstractMultitopic organic linkers can provide a means to organize metal cluster nodes in a regular three‐dimensional array. Herein, we show that isonicotinic acid N‐oxide (HINO) serves as the linker in the formation of a metal–organic framework featuring Dy2 single‐molecule magnets as nodes. Importantly, guest solvent exchange induces a reversible single‐crystal to single‐crystal transformation between the phases Dy2(INO)4(NO3)2⋅2 solvent (solvent=DMF (Dy2‐DMF), CH3CN (Dy2‐CH3CN)), thereby switching the effective magnetic relaxation barrier (determined by ac magnetic susceptibility measurements) between a negligible value for Dy2‐DMF and 76 cm−1 for Dy2‐CH3CN. Ab initio calculations indicate that this difference arises not from a significant change in the intrinsic relaxation barrier of the Dy2 nodes, but rather from a slowing of the relaxation rate of incoherent quantum tunneling of the magnetization by two orders of magnitude.
Hydrophobic Cysteine Poly(disulfide)‐based Redox‐Hypersensitive Nanoparticle Platform for Cancer Theranostics
Authors: Wu Jun , Zhao Lili , Xu Xiaoding , Bertrand Nicolas , Choi Won II , Yameen Basit , Shi Jinjun , Shah Vishva , Mulvale Matthew , MacLean James L. , Farokhzad Omid C. 
Published: June 2015

AbstractSelective tumor targeting and drug delivery are critical for cancer treatment. Stimulus‐sensitive nanoparticle (NP) systems have been designed to specifically respond to significant abnormalities in the tumor microenvironment, which could dramatically improve therapeutic performance in terms of enhanced efficiency, targetability, and reduced side‐effects. We report the development of a novel L‐cysteine‐based poly (disulfide amide) (Cys‐PDSA) family for fabricating redox‐triggered NPs, with high hydrophobic drug loading capacity (up to 25 wt % docetaxel) and tunable properties. The polymers are synthesized through one‐step rapid polycondensation of two nontoxic building blocks: L‐cystine ester and versatile fatty diacids, which make the polymer redox responsive and give it a tunable polymer structure, respectively. Alterations to the diacid structure could rationally tune the physicochemical properties of the polymers and the corresponding NPs, leading to the control of NP size, hydrophobicity, degradation rate, redox response, and secondary self‐assembly after NP reductive dissociation. In vitro and in vivo results demonstrate these NPs’ excellent biocompatibility, high selectivity of redox‐triggered drug release, and significant anticancer performance. This system provides a promising strategy for advanced anticancer theranostic applications.