bluuebunny/crossref_metadata_2025_split huggingface dataset:
Implications of L1 observations for slow solar wind formation by solar reconnection
Authors: Kepko L. , Viall N. M. , Antiochos S. K. , Lepri S. T. , Kasper J. C. , Weberg M. 
Published: April 2016

AbstractWhile the source of the fast solar wind is known to be coronal holes, the source of the slow solar wind has remained a mystery. Long time scale trends in the composition and charge states show strong correlations between solar wind velocity and plasma parameters, yet these correlations have proved ineffective in determining the slow wind source. We take advantage of new high time resolution (12 min) measurements of solar wind composition and charge state abundances at L1 and previously identified 90 min quasiperiodic structures to probe the fundamental timescales of slow wind variability. The combination of new high temporal resolution composition measurements and the clearly identified boundaries of the periodic structures allows us to utilize these distinct solar wind parcels as tracers of slow wind origin and acceleration. We find that each 90 min (2000 Mm) parcel of slow wind has near‐constant speed yet exhibits repeatable, systematic charge state and composition variations that span the entire range of statistically determined slow solar wind values. The classic composition‐velocity correlations do not hold on short, approximately hourlong, time scales. Furthermore, the data demonstrate that these structures were created by magnetic reconnection. Our results impose severe new constraints on slow solar wind origin and provide new, compelling evidence that the slow wind results from the sporadic release of closed field plasma via magnetic reconnection at the boundary between open and closed flux in the Sun's atmosphere.
On the detection of precipitation dependence on temperature
Authors: Zhou Yu , Luo Ming , Leung Yee 
Published: April 2016

AbstractEmploying their newly proposed interannual difference method (IADM), Liu et al. (2009) and Shiu et al. (2012) reported a shocking increase of around 100% K−1 in heavy precipitation with warming global temperature in 1979–2007. Such increase is alarming and prompts us to probe into the IADM. In this study, both analytical derivations and numerical analyses demonstrate that IADM provides no additional information to that of the conventional linear regression, and also, it may give a false indication of dependence. For clarity and simplicity, we therefore recommend linear regression analysis over the IADM for the detection of dependence. We also find that heavy precipitation decreased during the global warming hiatus, and the precipitation dependence on temperature drops by almost 50% when the study period is extended to 1979–2014 and it may keep dropping in the near future. The risk of having heavy precipitation under warming global temperature may have been overestimated.
Vertical heat flux in the ocean: Estimates from observations and from a coupled general circulation model
Authors: Cummins Patrick F. , Masson Diane , Saenko Oleg A. 
Published: April 2016

AbstractThe net heat uptake by the ocean in a changing climate involves small imbalances between the advective and diffusive processes that transport heat vertically. Generally, it is necessary to rely on global climate models to study these processes in detail. In the present study, it is shown that a key component of the vertical heat flux, namely that associated with the large‐scale mean vertical circulation, can be diagnosed over extra‐tropical regions from global observational data sets. This component is estimated based on the vertical velocity obtained from the geostrophic vorticity balance, combined with estimates of absolute geostrophic flow. Results are compared with the output of a non‐eddy resolving, coupled atmosphere‐ocean general circulation model. Reasonable agreement is found in the latitudinal distribution of the vertical heat flux, as well as in the area‐integrated flux below about 250 m depth. The correspondence with the coupled model deteriorates sharply at depths shallower than 250 m due to the omission of equatorial regions from the calculation. The vertical heat flux due to the mean circulation is found to be dominated globally by the downward contribution from the Southern Hemisphere, in particular the Southern Ocean. This is driven by the Ekman vertical velocity which induces an upward transport of seawater that is cold relative to the horizontal average at a given depth. The results indicate that the dominant characteristics of the vertical transport of heat due to the mean circulation can be inferred from simple linear vorticity dynamics over much of the ocean.
Generation of ELF waves during HF heating of the ionosphere at midlatitudes
Authors: Sharma A. S. , Eliasson B. , Shao X. , Papadopoulos K. 
Published: April 2016

AbstractModulated high‐frequency radio frequency heating of the ionospheric F region produces a local modulation of the electron temperature, and the resulting pressure gradient gives rise to a diamagnetic current. The oscillations of the diamagnetic current excite hydromagnetic waves in the ELF range that propagate away from the heated region. The generation of the waves in the 2–10 Hz range by a modulated heating in the midlatitude ionosphere is studied using numerical simulations of a collisional Hall‐magnetohydrodynamic model. To model the plasma processes in the midlatitude ionosphere the Earth's dipole magnetic field and typical ionospheric plasma parameters are used. As the hydromagnetic waves propagate away from the heated region in the F region, the varying plasma conditions lead to changes in their characteristics. Magnetosonic waves generated in the heating region and propagating down to the E region, where the Hall conductivity is dominant, excite oscillating Hall currents that produce shear Alfvén waves propagating along the field lines into the magnetosphere, where they propagate as the electromagnetic ion cyclotron (EMIC) and whistler waves. The EMIC waves propagate to the ion cyclotron resonance layer in the magnetosphere, where they are absorbed.
Is there a future for biologics in the management of chronic rhinosinusitis?
Authors: Lam Kent , Kern Robert C. , Luong Amber 
Published: April 2016

BackgroundChronic rhinosinusitis (CRS) is a heterogeneous inflammatory condition of the sinonasal mucosa consisting of poorly defined subtypes and characterized by variable clinical manifestations, responses to therapy, and underlying pathophysiologies. In the related disorder of asthma, progress has been made in defining disease subtypes on both clinical and pathophysiologic levels, facilitating the development of targeted biologic pharmacotherapy. The potential role of these drugs for the management of CRS will be reviewed. The objective of this work is to highlight the emerging therapeutic targets in CRS in light of evolving treatment options for asthma and enhanced understandings of the clinical manifestations and pathophysiology of CRS.MethodsThis article is a review of recent studies regarding current and future advances in biomarker‐directed therapies in the medical treatment of CRS.ResultsVarious biologic therapies used in the management of asthma have demonstrated clinical promise for CRS, particularly within the CRS with nasal polyposis (CRSwNP) phenotype. Several randomized, double‐blind, placebo‐controlled studies increasingly support the targeting of immunoglobulin E (IgE) and interleukin (IL)‐5 pathways to improve outcome measures in CRSwNP patients. The IL‐4/IL‐13 pathway and other type 2 inflammatory pathways have also shown potential as targets for CRSwNP, but all pathways require further investigation.ConclusionRecalcitrant CRS in the United States and Europe is most commonly associated with nasal polyposis and a type 2 cytokine skewing in the tissue, resulting in tissue infiltration of eosinophils, mast cells, and basophils. Targeting biomarkers of the associated type 2 pathways may be a practical treatment option for recalcitrant CRSwNP in the future.
3D‐Anordnung anorganischer kolloidaler Nanokristalle zu Gelen und Aerogelen
Authors: Sayevich Vladimir , Cai Bin , Benad Albrecht , Haubold Danny , Sonntag Luisa , Gaponik Nikolai , Lesnyak Vladimir , Eychmüller Alexander 
Published: April 2016

AbstractWir stellen in dieser Arbeit eine effiziente Anordnungsstrategie verschiedener elektrostatisch stabilisierter Halbleiternanokristalle (NK) vor, welche sich über geeignete Ionen zu einem mehrfach verzweigten Gelnetzwerk verbinden. Diese rein anorganischen, ungeordneten 3D‐Strukturen profitieren von starken interpartikulären Wechselwirkungen, was in einem verbesserten Ladungstransport zwischen verschiedenen NK, mit unterschiedlichen Morphologien, Zusammensetzungen, Größen sowie funktionalisierten Liganden resultiert. Darüber hinaus weisen die erhaltenen getrockneten Gelmonolithe (Aerogelen) eine hochporöse Netzwerkstruktur auf, ohne dass dabei die Quantenbeschränkung der Baueinheiten beeinträchtigt wird. Insbesondere anorganische Halbleiteraerogele, wie hier aus kolloidalen, 4.5 nm großen CdSe‐NK aufgebaut, die anschließend mit Iodidliganden modifiziert und über Cd2+‐Ionen verbrückt wurden, zeigen eine große spezifische Oberfläche von 146 m2 g−1.
In Situ Functionalized Polymers for siRNA Delivery
Authors: Priegue Juan M. , Crisan Daniel N. , Martínez‐Costas José , Granja Juan R. , Fernandez‐Trillo Francisco , Montenegro Javier 
Published: April 2016

AbstractA new method is reported herein for screening the biological activity of functional polymers across a consistent degree of polymerization and in situ, that is, under aqueous conditions and without purification/isolation of candidate polymers. In brief, the chemical functionality of a poly(acryloyl hydrazide) scaffold was activated under aqueous conditions using readily available aldehydes to obtain amphiphilic polymers. The transport activity of the resulting polymers can be evaluated in situ using model membranes and living cells without the need for tedious isolation and purification steps. This technology allowed the rapid identification of a supramolecular polymeric vector with excellent efficiency and reproducibility for the delivery of siRNA into human cells (HeLa‐EGFP). The reported method constitutes a blueprint for the high‐throughput screening and future discovery of new polymeric functional materials with important biological applications.
Asymmetric Induction at Remote Quaternary Centers of Cyclohexadienones by Rhodium‐Catalyzed Conjugate Hydrosilylation
Authors: Naganawa Yuki , Kawagishi Mayu , Ito Jun‐ichi , Nishiyama Hisao 
Published: April 2016

AbstractThe enantioselective desymmetrizing conjugate hydrosilylation of prochiral differently γ,γ‐disubstituted cyclohexadienone derivatives 2 to furnish the corresponding cyclohexenones 4 with a remote chiral all‐carbon quaternary center at the γ position is described. Chiral rhodium–bis(oxazolinyl)phenyl complexes 1 were effective catalysts for this transformation. This catalytic system was extended to the asymmetric transformation of spirocarbocyclic cyclohexadienones 5 to give the corresponding products 6 with high enantiomeric ratios.
Eine Phytochrom‐Sensordomäne ermöglicht eine Rezeptoraktivierung durch rotes Licht
Authors: Reichhart Eva , Ingles‐Prieto Alvaro , Tichy Alexandra‐Madelaine , McKenzie Catherine , Janovjak Harald 
Published: April 2016

AbstractOptogenetik und Photopharmakologie ermöglichen eine lichtgesteuerte räumliche und zeitliche Manipulation von Prozessen in Zellen und in Tiermodellen. Obwohl rotes Licht durch minimale Toxizität und gute Gewebedurchdringung überzeugt, sind nur wenige für rotes Licht empfindliche optogenetische Hilfsmittel bekannt. Wir haben eine neue, durch rotes Licht aktivierte Homodimerisierungsdomäne in Form der Sensordomäne des cyanobakteriellen Phytochroms 1 entwickelt, die robust und ohne Zytotoxizität in menschlichen Zellen exprimiert werden kann. Mithilfe dieser Domäne induzierten wir die Dimerisierung und Aktivierung von zwei Rezeptor‐Tyrosinkinasen, dem Fibroblasten‐Wachstumsfaktor Rezeptor 1 und dem Neurotrophinrezeptor trkB. Auf diese Weise waren wir in der Lage, den MAPK/ERK‐Signalweg durch Gewebe hindurch zu aktivieren und mehrfarbige Signaltransduktionsexperimente durchzuführen. Die Homodimerisierung von Proteinen und die Aktivierung von Rezeptor‐Tyrosinkinasen auf Basis von rotem Licht sind vielseitige Erweiterungen des optogenetischen Repertoires.
Structural and Spectroscopic Characterization of a High‐Spin {FeNO}6 Complex with an Iron(IV)−NO− Electronic Structure
Authors: Speelman Amy L. , Zhang Bo , Krebs Carsten , Lehnert Nicolai 
Published: April 2016

AbstractAlthough the interaction of low‐spin ferric complexes with nitric oxide has been well studied, examples of stable high‐spin ferric nitrosyls (such as those that could be expected to form at typical non‐heme iron sites in biology) are extremely rare. Using the TMG3tren co‐ligand, we have prepared a high‐spin ferric NO adduct ({FeNO}6 complex) via electrochemical or chemical oxidation of the corresponding high‐spin ferrous NO {FeNO}7 complex. The {FeNO}6 compound is characterized by UV/Visible and IR spectroelectrochemistry, Mössbauer and NMR spectroscopy, X‐ray crystallography, and DFT calculations. The data show that its electronic structure is best described as a high‐spin iron(IV) center bound to a triplet NO− ligand with a very covalent iron−NO bond. This finding demonstrates that this high‐spin iron nitrosyl compound undergoes iron‐centered redox chemistry, leading to fundamentally different properties than corresponding low‐spin compounds, which undergo NO‐centered redox transformations.
Controlling the Atomic Structure of Au30 Nanoclusters by a Ligand‐Based Strategy
Authors: Higaki Tatsuya , Liu Chong , Zeng Chenjie , Jin Renxi , Chen Yuxiang , Rosi Nathaniel L. , Jin Rongchao 
Published: April 2016

AbstractWe report the X‐ray structure of a gold nanocluster with 30 gold atoms protected by 18 1‐adamantanethiolate ligands (formulated as Au30(S‐Adm)18). This nanocluster exhibits a threefold rotationally symmetrical, hexagonal‐close‐packed (HCP) Au18 kernel protected by six dimeric Au2(SR)3 staple motifs. This new structure is distinctly different from the previously reported Au30S(S‐tBu)18 nanocluster protected by 18 tert‐butylthiolate ligands and one sulfido ligand with a face‐centered cubic (FCC) Au22 kernel. The Au30(S‐Adm)18 nanocluster has an anomalous solubility (it is only soluble in benzene but not in other common solvents). This work demonstrates a ligand‐based strategy for controlling nanocluster structure and also provides a method for the discovery of possibly overlooked clusters because of their anomalous solubility.
Heterologous Production of Fungal Maleidrides Reveals the Cryptic Cyclization Involved in their Biosynthesis
Authors: Williams Katherine , Szwalbe Agnieszka J. , Mulholland Nicholas P. , Vincent Jason L. , Bailey Andrew M. , Willis Christine L. , Simpson Thomas J. , Cox Russell J. 
Published: April 2016

AbstractFungal maleidrides are an important family of bioactive secondary metabolites that consist of 7, 8, or 9‐membered carbocycles with one or two fused maleic anhydride moieties. The biosynthesis of byssochlamic acid (a nonadride) and agnestadride A (a heptadride) was investigated through gene disruption and heterologous expression experiments. The results reveal that the precursors for cyclization are formed by an iterative highly reducing fungal polyketide synthase supported by a hydrolase, together with two citrate‐processing enzymes. The enigmatic ring formation is catalyzed by two proteins with homology to ketosteroid isomerases, and assisted by two proteins with homology to phosphatidylethanolamine‐binding proteins.
Stereoselective Substrate‐Controlled Asymmetric Syntheses of both 2,5‐cis‐ and 2,5‐trans‐Tetrahydrofuranoid Oxylipids: Stereodivergent Intramolecular Amide Enolate Alkylation
Authors: Jang Hongjun , Shin Iljin , Lee Dongjoo , Kim Hyoungsu , Kim Deukjoon 
Published: April 2016

AbstractThe concise, highly stereoselective, substrate‐controlled asymmetric total syntheses of both 2,5‐cis‐ and 2,5‐trans‐tetrahydrofuranoid nematocidal oxylipids from the Australian brown algae Notheia anomala have been accomplished in a stereodivergent fashion. The highly stereoselective intramolecular amide enolate alkylation strategy provides access to both stereoisomers of the 3‐hydroxy‐2,5‐disubstituted tetrahydrofuran core of these marine natural products through chelate and nonchelate control, which is driven by the C3‐hydroxy protecting group. This approach offers an optional and highly stereoelective access to any of the eight possible stereoisomers of the 2,5‐disubstituted‐3‐oxygenated tetrahydrofuran skeleton, an important structural feature which is present in many biologically active natural products.
Z‐Selective (Cross‐)Dimerization of Terminal Alkynes Catalyzed by an Iron Complex
Authors: Rivada‐Wheelaghan Orestes , Chakraborty Subrata , Shimon Linda J. W. , Ben‐David Yehoshoa , Milstein David 
Published: April 2016

AbstractEfficient iron‐catalyzed homocoupling of terminal alkynes and cross‐dimerization of aryl acetylenes with trimethylsilylacetylene is reported. The complex [Fe(H)(BH4)(iPr‐PNP)] (1) catalyzed the (cross‐)dimerization of alkynes at room temperature, with no need for a base or other additives, to give the corresponding dimerized products with Z selectivity in excellent yields (79–99 %).
Enhanced Photoexcited Carrier Separation in Oxygen‐Doped ZnIn2S4 Nanosheets for Hydrogen Evolution
Authors: Yang Wenlong , Zhang Lei , Xie Junfeng , Zhang Xiaodong , Liu Qinghua , Yao Tao , Wei Shiqiang , Zhang Qun , Xie Yi 
Published: April 2016

AbstractLimited by the relatively sluggish charge‐carrier separation in semiconductors, the photocatalytic performance is still far below what is expected. Herein, a model of ZnIn2S4 (ZIS) nanosheets with oxygen doping is put forward to obtain in‐depth understanding of the role that doping atoms play in photocatalysis. It shows enhanced photocatalytic activity compared with pristine ZIS. The electron dynamics analyzed by ultrafast transient absorption spectroscopy reveals that the average recovery lifetime of photoexcited electrons is increased by 1.53 times upon oxygen incorporation into the ZIS crystals, indicating enhanced separation of photoexcited carriers in oxygen‐doped ZIS nanosheets. As expected, the oxygen‐doped ZIS nanosheets show a remarkably improved photocatalytic activity with a hydrogen evolution rate of up to 2120 μmol h−1 g−1 under visible‐light irradiation, which is 4.5 times higher than that of the pristine ZIS nanosheets.
Plugging properties and profile control effects of crosslinked polyacrylamide microspheres
Authors: Wang Bo , Lin Meiqin , Guo Jinru , Wang Dianlin , Xu Fengqiang , Li Mingyuan 
Published: April 2016

ABSTRACTIn this article, the morphology, particle size, and plugging properties of crosslinked polyacrylamide (CPAM) microspheres were investigated through optical microscopy, scanning electron microscopy (SEM), nuclear‐pore membrane filtration experiments, a micro‐visual model, sandpack experiments, parallel twin‐tube plugging, and oil displacement experiments. The results revealed that the primary particle sizes of the CPAM microspheres ranged from several hundreds of nanometers to 5 μm; however, after the microspheres were fully swelled in water, their sizes increased by approximately five times of their original sizes. As a CPAM microsphere dispersion system had good dispersibility and deformation capabilities, a 1.2 μm nuclear‐pore membrane as well as the deep part of a sandpack tube could be effectively plugged. Consequently, the flow diversion effect was achieved in the vertical and planar directions. When the CPAM microspheres migrated in porous media, they could displace residual oil on the pole wall and water flow channel to realize the synchronization of profile control and coordination and improve recovery efficiency. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43666.
Sorption/release of diclofenac sodium in/from free‐standing poly(acrylic acid)/poly(ethyleneimine) multilayer films
Authors: Ghiorghita Claudiu‐Augustin , Bucatariu Florin , Dragan Ecaterina Stela 
Published: April 2016

ABSTRACTPolyelectrolyte multilayer films deposited onto various substrates have been used extensively as drug delivery systems. However, little attention has been paid to the release of drugs from free‐standing polymeric films. Herein, we report the construction of thermal crosslinked free‐standing poly(acrylic acid) (PAA)/branched poly(ethyleneimine) (PEI) multilayer films composed of 25 double layers [(PAA/PEI)25] and their use in sorption/release of diclofenac sodium (DS). The (PAA/PEI)25 multilayer films were characterized by scanning electron microscopy, potentiometric titrations and Fourier transform infrared spectroscopy, while the sorption/release of DS was monitored by UV–Vis spectroscopy. The DS sorption equilibrium data were fitted with five isotherm models (Langmuir, Freundlich, Sips, Dubinin–Radushkevich, and Temkin). The maximum equilibrium sorption capacity, qm, given by the Langmuir model was 32.42 mg DS/g. The Korsmeyer–Peppas semiempirical equation showed that the release of DS from the free‐standing (PAA/PEI)25 films proceeded by pseudo‐Fickian diffusion, irrespective of the releasing media. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43752.
Chopping high‐molecular weight poly(1,4‐butylene carbonate‐co‐aromatic ester)s for macropolyol synthesis
Authors: Park Geun Ho , Lee Seul , Park Su Hyun , Eo Seong Chan , Kim Jin Gu , Lee Bun Yeoul 
Published: April 2016

ABSTRACTThe condensation of a mixture of dimethyl carbonate and phthalate derivatives with 1,4‐butanediol (BD), catalyzed by sodium alkoxide, generated high‐molecular weight poly(1,4‐butylene carbonate‐co‐aromatic ester)s with molecular weights (Mn) of 50–120 kDa. The subsequent addition of polyols [BD, glycerol propoxylate, 1,1,1‐tris(hydroxymethyl)ethane, or pentaerythritol] chopped these high‐molecular weight polymers to afford macrodiols or macropolyols with facile control of their molecular weights (Mn, 2000–3000 Da) and unique chain topological compositions. Macropolyols prepared by chopping poly(1,4‐butylene carbonate‐co‐terephthalate) were waxy in nature, whereas those containing isophthalate and phthalate units were oily. The macropolyols synthesized by this chopping method may have potential applications in the polyurethane industry. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43754.
Airborne copper exposure in school environments associated with poorer motor performance and altered basal ganglia
Authors: Pujol Jesus , Fenoll Raquel , Macià Dídac , Martínez‐Vilavella Gerard , Alvarez‐Pedrerol Mar , Rivas Ioar , Forns Joan , Deus Joan , Blanco‐Hinojo Laura , Querol Xavier , Sunyer Jordi 
Published: April 2016

AbstractIntroductionChildren are more vulnerable to the effects of environmental elements. A variety of air pollutants are among the identified factors causing neural damage at toxic concentrations. It is not obvious, however, to what extent the tolerated high levels of air pollutants are able to alter brain development. We have specifically investigated the neurotoxic effects of airborne copper exposure in school environments.MethodsSpeed and consistency of motor response were assessed in 2836 children aged from 8 to 12 years. Anatomical MRI, diffusion tensor imaging, and functional MRI were used to directly test the brain repercussions in a subgroup of 263 children.ResultsHigher copper exposure was associated with poorer motor performance and altered structure of the basal ganglia. Specifically, the architecture of the caudate nucleus region was less complete in terms of both tissue composition and neural track water diffusion. Functional MRI consistently showed a reciprocal connectivity reduction between the caudate nucleus and the frontal cortex.ConclusionsThe results establish an association between environmental copper exposure in children and alterations of basal ganglia structure and function.