bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of MODIS Terra radiometric calibration improvements on Collection 6 Deep Blue aerosol products: Validation and Terra/Aqua consistency
Authors: Sayer A. M. , Hsu N. C. , Bettenhausen C. , Jeong M.‐J. , Meister G. 
Published: November 2015

AbstractThe Deep Blue (DB) algorithm's primary data product is midvisible aerosol optical depth (AOD). DB applied to Moderate Resolution Imaging Spectroradiometer (MODIS) measurements provides a data record since early 2000 for MODIS Terra and mid‐2002 for MODIS Aqua. In the previous data version (Collection 5, C5), DB production from Terra was halted in 2007 due to sensor degradation; the new Collection 6 (C6) has both improved science algorithms and sensor radiometric calibration. This includes additional calibration corrections developed by the Ocean Biology Processing Group to address MODIS Terra's gain, polarization sensitivity, and detector response versus scan angle, meaning DB can now be applied to the whole Terra record. Through validation with Aerosol Robotic Network (AERONET) data, it is shown that the C6 DB Terra AOD quality is stable throughout the mission to date. Compared to the C5 calibration, in recent years the RMS error compared to AERONET is smaller by ∼0.04 over bright (e.g., desert) and ∼0.01–0.02 over darker (e.g., vegetated) land surfaces, and the fraction of points in agreement with AERONET within expected retrieval uncertainty higher by ∼10% and ∼5%, respectively. Comparisons to the Aqua C6 time series reveal a high level of correspondence between the two MODIS DB data records, with a small positive (Terra‐Aqua) average AOD offset <0.01. The analysis demonstrates both the efficacy of the new radiometric calibration efforts and that the C6 MODIS Terra DB AOD data remain stable (to better than 0.01 AOD) throughout the mission to date, suitable for quantitative scientific analyses.
Size‐frequency distribution of crater populations in equilibrium on the Moon
Authors: Xiao Zhiyong , Werner Stephanie C. 
Published: November 2015

AbstractOverprinting of craters by subsequent impacts and topographic degradation complicates crater statistics, especially for old surfaces and small‐diameter crater populations. A crater population is regarded as in equilibrium at a particular crater size when smaller craters are being produced at the same rate at which they are being destroyed. Evaluating the equilibrium state of crater populations is challenging, and empirical equilibrium densities are frequently inferred. By performing careful crater counts and cross comparisons on several lunar surfaces, we study the size‐frequency distributions (SFD) for the crater populations, which have portions in equilibrium. The results are one of the few observational constraints on the SFD of crater populations in equilibrium, showing that referring to empirical equilibrium densities is not safe for evaluating the equilibrium states of crater populations. Equilibrium densities are not positively correlated with the ages of crater populations, and some populations in equilibrium have crater densities less than those previously believed to represent equilibrium conditions. Besides the SFD of the production population, different crater removal rates at different diameters also affect the SFD of crater populations in equilibrium. The equilibrium onset diameter (Deq) of a crater population can be translated to model ages because older populations have larger Deq, and those for same‐aged surfaces are comparable. We show that the crater populations studied here are in equilibrium at much smaller diameters than those predicted for same‐aged surfaces by crater degradation models, thus indicating lower crater degradation rates on the Moon, and/or younger ages of the counting areas.
Von atomistischer Oberflächenchemie zu Nanokristallen funktionaler Chalkogenide
Authors: Deringer Volker L. , Dronskowski Richard 
Published: November 2015

AbstractDie Synthese und die Nutzbarmachung von Nanokristallen sind hochaktuelle Forschungsfelder, doch setzen sie ein gründliches Verständnis der beteiligten Kristallflächen voraus. In diesem Kurzaufsatz schlagen wir ebendiesen Bogen von Oberflächen zu freien und weiter zu naßchemisch synthetisierten Nanokristallen, und zwar exemplarisch für Bleiselenid (PbSe), Zinntellurid (SnTe) und ihre direkten chemischen Verwandten. Wir diskutieren experimentelle Einblicke und darüber hinaus die – zunehmend einflußreiche – quantenchemische Simulation von Oberflächen und Nanokristallen. Was kann die Theorie heute leisten, was möglicherweise morgen, was kann sie eben nicht? Die Beantwortung dieser Fragen und ihre geschickte Verknüpfung mit Experimenten könnten neue, atomistisch (und damit chemisch) geleitete Perspektiven in der Nanosynthese eröffnen.
Reactivity of Gold Complexes towards Elementary Organometallic Reactions
Authors: Joost Maximilian , Amgoune Abderrahmane , Bourissou Didier 
Published: November 2015

AbstractFor a while, the reactivity of gold complexes was largely dominated by their Lewis acid behavior. In contrast to the other transition metals, the elementary steps of organometallic chemistry—oxidative addition, reductive elimination, transmetallation, migratory insertion—have scarcely been studied in the case of gold or even remained unprecedented until recently. However, within the last few years, the ability of gold complexes to undergo these fundamental reactions has been unambiguously demonstrated, and the reactivity of gold complexes was shown to extend well beyond π‐activation. In this Review, the main achievements described in this area are presented in a historical context. Particular emphasis is set on mechanistic studies and structure determination of key intermediates. The electronic and structural parameters delineating the reactivity of gold complexes are discussed, as well as the remaining challenges.
From Atomistic Surface Chemistry to Nanocrystals of Functional Chalcogenides
Authors: Deringer Volker L. , Dronskowski Richard 
Published: November 2015

AbstractSynthesis and utilization of nanocrystals are highly active fields of current research, but they require a thorough understanding of the underlying crystal surfaces. In this Minireview, we span the arc from surfaces to free nanocrystals, and onward to their chemical synthesis, using as examples lead selenide (PbSe), tin telluride (SnTe), and their direct chemical relatives. Besides experimental insights, we highlight the increasingly influential role played by quantum‐chemical simulations of surfaces and nanocrystals. What can theory do today, or possibly tomorrow; where are its limits? Answering these questions, and skillfully linking them to experiments, could open up new atomistically (that is, chemically) guided perspectives for nanosynthesis.
Reversible Inhibitors Arrest ClpP in a Defined Conformational State that Can Be Revoked by ClpX Association
Authors: Pahl Axel , Lakemeyer Markus , Vielberg Marie‐Theres , Hackl Mathias W. , Vomacka Jan , Korotkov Vadim S. , Stein Martin L. , Fetzer Christian , Lorenz‐Baath Katrin , Richter Klaus , Waldmann Herbert , Groll Michael , Sieber Stephan A. 
Published: November 2015

AbstractCaseinolytic protease P (ClpP) is an important regulator of Staphylococcus aureus pathogenesis. A high‐throughput screening for inhibitors of ClpP peptidase activity led to the identification of the first non‐covalent binder for this enzyme class. Co‐crystallization of the small molecule with S. aureus ClpP revealed a novel binding mode: Because of the rotation of the conserved residue proline 125, ClpP is locked in a defined conformational state, which results in distortion of the catalytic triad and inhibition of the peptidase activity. Based on these structural insights, the molecule was optimized by rational design and virtual screening, resulting in derivatives exceeding the potency of previous ClpP inhibitors. Strikingly, the conformational lock is overturned by binding of ClpX, an associated chaperone that enables proteolysis by substrate unfolding in the ClpXP complex. Thus, regulation of inhibitor binding by associated chaperones is an unexpected mechanism important for ClpP drug development.
Highly Diastereoselective Synthesis of Methylenecyclobutanes by Merging Boron‐Homologation and Boron‐Allylation Strategies
Authors: Eisold Michael , Didier Dorian 
Published: November 2015

AbstractA highly diastereoselective synthesis of methylenecyclobutanes possessing a quaternary stereocenter is reported, in which boron homologation of an easily‐generated cyclobutenylmetal species is performed, followed by an allylation reaction. Combining three steps in a one‐pot process further optimized the method, which afforded the expected adducts in excellent yields and stereoselectivity, starting from commercially available 4‐bromobutyne.
Gap formation and its consequence in the evolution of SMBHs binaries in galaxy mergers
Authors: del Valle L. , Escala A. 
Published: November 2015

AbstractMotivated by the theoretical and observational evidence that after a major merger of gas‐rich galaxies a massive gaseous disk with a SMBH binary will be formed in the nuclear region of the remnant, we study the interaction between an unequal mass binary and an isothermal circumbinary disk. We focus our study in the transport of angular momentum from the binary to the disk and how this transport can result on the formation of a cavity or gap in the gaseous disk. We propose that, for comparable mass binaries, this exchange of angular momentum is driven by the gravitational interaction of the binary and a strong non‐axisymmetric density perturbation that is formed in the disk as response to the presence of the gravitational field of the binary. We compare the efficiency of this gravitational torque on extract angular momentum from the binary with the efficiency of redistribution of the extracted angular momentum in the disk to derive a gap‐opening criterion. We run a set of SPH simulations of binaries embedded in isothermal gaseous disks to test our gap‐opening criterion. We find that our gap‐opening criterion successfully predicts in which simulations a gap will form on the disk. We also run simulations of merging galaxies and we apply our criterion to the more real SMBHB‐Disk systems that are formed in situ in these simulations. We find that, in the conditions of our galaxy mergers simulations, the formation of a circumbinary gap is unlikely. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mass composition measurements at the Pierre Auger Observatory
Authors: Molina Bueno L. , Pierre Auger Collaboration  
Published: November 2015

AbstractThe Pierre Auger Observatory is the largest ultra‐high energy cosmic ray experiment built so far. It is a hybrid detector, since it measures both the fluorescence light emitted while the air showers develop in the atmosphere and the particles reaching the ground. We present the results related to the mass composition of ultra‐high energy cosmic rays as obtained from both types of measurements. The depth at which the maximum of the electromagnetic development takes place and its fluctuations are the most sensitive parameters to infer the nature of the cosmic rays. In addition, we present the latest muon measurements that can be used to test and constrain models of hadronic interactions at energies larger than those reached at LHC. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Achievements in solar neutrino physics with the Borexino detector
Authors: Miramonti L. , Nachname Vorname 
Published: November 2015

AbstractBorexino is an organic liquid scintillator detector located in the Gran Sasso National Laboratory in central Italy. It has been designed for real‐time spectroscopy of low energy solar neutrinos. In Phase I of the experiment lasting for three years, between May 2007 and May 2010, the Collaboration performed the first independent measurements of 7Be, 8B, and pep solar neutrino fluxes. After a dedicated purification campaign of the liquid scintillator in 2011, Borexino entered into Phase II which allowed to investigate the seasonal modulation in the 7Be signal. In 2014, Borexino provided the first direct real time measurement of pp neutrinos accomplishing the whole pp‐cycle that powers the Sun. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
From cold to hot nuclear matter
Authors: Bratkovskaya E. L. , Cassing W. , Konchakovski V. P. , Toneev V. D. 
Published: November 2015

AbstractThe dynamics of partons and hadrons in relativistic nucleus‐nucleus collisions is analyzed within the Parton‐HadronString Dynamics (PHSD) transport approach which is based on a dynamical quasiparticle model for the partonic phase (DQPM) including a dynamical hadronization scheme with covariant transition rates. The PHSD approach is applied to nucleus‐nucleus collisions from FAIR/NICA to LHC energies. The traces of partonic interactions are found in particular in the directed and elliptic flow of hadrons and in their transverse mass spectra. Whereas at RHIC and LHC energies the dynamics is dominated by partonic degrees‐of‐freedom in the hot QGP, we find at FAIR/NICA energies a moderately hot but dense matter where chiral symmetry restoration and hadronic potentials appear to play a major role. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Evolution of stellar entropy
Authors: de Souza R.A. , de Avellar M.G.B. , Horvath J.E. 
Published: November 2015

AbstractAn appraisal of the behavior of stellar entropy along stellar evolution is made. It is shown that the entropy per baryon of a star of a fixed baryon number decreases monotonically with increasing compactness of the star. The same entropy per baryon increases only whenever an irreversible collapse of the star happens. The recent proposals for a gravitational entropy related to curvature may justify the huge increase of the entropy in the ultimate collapse to a black hole. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Anisotropic structure equations in magnetized quark stars
Authors: Manreza Paret D. , Horvath J. H. , Perez Martinez A. 
Published: November 2015

AbstractIt is well‐known that a magnetic field in a fermion system breaks the SO(3) symmetry, giving rise to an anisotropy in the energy‐momentum tensor and consequently in the equation of state (EoS). Thus, the stellar structure equations of magnetized quark stars (QS) demand to be derived from a more appropriate cylindrical metric. In this work we obtain these equations considering the magnetized quark matter in two phases: Magnetized Strange Quark Matter (MSQM) and Magnetized Color Flavor Locked Phase (MCFL). The main outcome of our work is the value of the maximum magnetic field that an star can hold, i.e. 1018 G. This upper bound is closely related to the violation of the virial relations and also with the instability associated with parity‐violation weak processes during the collapse of supernovae. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magneto‐rotational and thermal evolution of young neutron stars
Authors: Popov S. B. 
Published: November 2015

AbstractAfter a brief review of population synthesis of close‐by cooling neutron stars, I focus on the interpretation of the dichotomy of spin periods of near‐by coolers. The existence of two well separated groups – short period (∼ 0.1–0.3 s) radio pulsars and long period (∼ 3–10 s) radio quiet sources, aka the Magnificent Seven, – can not easily be explained by unified models developed recently (Popov et al. 2010; Gullón et al. 2014). I speculate that the most natural solution of the problem can be in the bimodal initial magnetic‐field distribution related to the existence of an additional mechanism of field generation in magnetars. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The effects of superhigh magnetic fields on the equations of state of neutron stars
Authors: Gao Z. F. , Wang N. , XU Y. , Shan H. , Li X.‐D. 
Published: November 2015

AbstractBy introducing Dirac's δ‐function in superhigh magnetic fields, we deduce a general formula for the pressure of degenerate and relativistic electrons, Pe, which is suitable for superhigh magnetic fields, discuss the quantization of Landau levels of electrons, and consider the quantum electrodynamic(QED) effects on the equations of states (EOSs) for different matter systems. The main conclusions are as follows: the stronger the magnetic field strength, the higher the electron pressure becomes; compared with a common radio pulsar, a magnetar could be a more compact oblate spheroid‐like deformed neutron star due to the anisotropic total pressure; and an increase in the maximum mass of a magnetar is expected because of the positive contribution of the magnetic field energy to the EoS of the star. Since this is an original work in which some uncertainties could exist, modifications and improvements of our theory should be considered in our future studies. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Extended canonical field theory of matter and space‐time
Authors: Struckmeier J. , Vasak D. , Stoecker H. 
Published: November 2015

AbstractAny physical theory that follows from an action principle should be invariant in its form under mappings of the reference frame in order to comply with the general principle of relativity. The required form‐invariance of the action principle implies that the mapping must constitute a particular extended canonical transformation. In the realm of the covariant Hamiltonian formulation of field theory, the term “extended” implies that not only the fields but also the space‐time geometry is subject to transformation. A canonical transformation maintains the general form of the action principle by simultaneously defining the appropriate transformation rules for the fields, the conjugate momentum fields, and the transformation rule for the Hamiltonian. Provided that the given system of fields exhibits a particular global symmetry, the associated extended canonical transformation determines an amended Hamiltonian that is form‐invariant under the corresponding local symmetry. This will be worked out for a Hamiltonian system of scalar and vector fields that is presupposed to be form‐invariant under space‐time transformations x µ ∼→ X µ with δX µ/δxv = const., hence under global space‐time transformations such as the Poincar´e transformation. The corresponding amended system that is form‐invariant under local space‐time transformations δX µ/δxv ∼ const. then describes the coupling of the fields to the space‐time geometry and thus yields the dynamics of space‐time that is associated with the given physical system. Non‐zero spin matter determines thereby the space‐time curvature via a well‐defined source term in a covariant Poisson‐type equation for the Riemann tensor. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Under‐saturation of quarks at early stages of relativistic nuclear collisions: The hot glue initial scenario and its observable signatures
Authors: Stöcker H. , Beitel M. , Biró T. S. , Csernai L. P. , Gallmeister K. , Gorenstein M. I. , Greiner C. , Mishustin I. N. , Panero M. , Raha S. , Satarov L. M. , Schramm S. , Senzel F. , Sinha B. , Steinheimer J. , Struckmeier J. , Vovchenko V. , Xu Z. , Zhou K. , Zhuang P. 
Published: November 2015

AbstractThe early stage of high multiplicity nuclear collisions is represented by a nearly quarkless, hot, deconfined pure gluon plasma. These new scenario should be characterized by a suppression of high pT photons and dileptons as well as by reduced baryon to meson ratios. We present the numerical results for central Pb+Pb collisions at the LHC energies by using the ideal Bjorken hydrodynamics with time‐dependent quark fugacity. It is shown that about 25 % of final total entropy is generated during the hydrodynamic evolution of chemically undersaturated quark‐gluon plasma. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Urea‐induced binding between diclofenac sodium and bovine serum albumin: a spectroscopic insight
Authors: Dohare Neeraj , Khan Abbul Bashar , Athar Fareeda , Thakur Sonu Chand , Patel Rajan 
Published: November 2015

AbstractWe investigated the interaction of diclofenac sodium (Dic.Na) with bovine serum albumin (BSA) in the absence and presence of urea using different spectroscopic techniques. A fluorescence quenching study revealed that the Stern–Volmer quenching constant decreases in the presence of urea, decreasing further at higher urea concentrations. The binding constant and number of binding sites were also evaluated for the BSA–Dic.Na interaction system in the absence and presence of urea using a modified Stern–Volmer equation. The binding constant is greater at high urea concentrations, as shown by the fluorescence results. In addition, for the BSA–Dic.Na interaction system, a static quenching mechanism was observed, which was further confirmed using time‐resolved fluorescence spectroscopy. UV–vis spectroscopy provided information about the formation of a complex between BSA and Dic.Na. Circular dichroism was carried out to explain the conformational changes in BSA induced by Dic.Na in the absence and presence of urea. The presence of urea reduced the α‐helical content of BSA as the Dic.Na concentration varied. The distance r between the donor (BSA) and acceptor (Dic.Na) was also obtained in the absence and presence of urea, using fluorescence resonance energy transfer. Copyright © 2015 John Wiley & Sons, Ltd.
Iron Oxide Nanoparticles Modified with Carbon Quantum Nanodots for the Stabilization of Palladium Nanoparticles: An Efficient Catalyst for the Suzuki Reaction in Aqueous Media under Mild Conditions
Authors: Gholinejad Mohammad , Seyedhamzeh Mohammad , Razeghi Mehran , Najera Carmen , Kompany‐Zareh Mohsen 
Published: November 2015

AbstractMagnetic Fe3O4 nanoparticles (NPs) functionalized with carbon dots (C‐dots) that contain carboxylic acid and hydroxyl groups were synthesized successfully and used for the reduction of PdII and the formation of Pd NPs. The new material was characterized by SEM, TEM, energy‐dispersive spectroscopy, solid UV spectroscopy, vibrating sample magnetometry, XRD, and X‐ray photoelectron spectroscopy and was used as a very efficient catalyst in the Suzuki–Miyaura cross‐coupling reaction of aryl bromides and chlorides with arylboronic acids in aqueous media. Design of experiments indicates that the use of 0.22 mol % of Pd, K2CO3 as the base, and aqueous ethanol are the best reaction conditions. The reactions of aryl bromides take place at room temperature, and aryl chlorides react at 80 °C. The easily synthesized and air‐stable catalyst Pd@C‐dots@Fe3O4 NPs could be separated from the reaction mixture by using an external magnet and reused in eight consecutive runs with no significant loss of catalytic activity.
Taming Tin(IV) Polyazides
Authors: Campbell Rory , Davis Martin F. , Fazakerley Mathew , Portius Peter 
Published: November 2015

AbstractThe first charge‐neutral Lewis base adducts of tin(IV) tetraazide, [Sn(N3)4(bpy)], [Sn(N3)4(phen)] and [Sn(N3)4(py)2], and the salt bis{bis(triphenylphosphine)iminium} hexa(azido)stannate [(PPN)2Sn(N3)6] (bpy = 2,2′‐bipyridine; phen = 1,10‐phenanthroline; py = pyridine; PPN = N(PPh3)2) have been prepared using covalent or ionic azide‐transfer reagents and ligand‐exchange reactions. The azides were isolated on the 0.3 to 1 g scale and characterized by IR and NMR spectroscopies, microanalytical and thermal methods and their molecular structures determined by single‐crystal XRD. All complexes have a distorted octahedral Sn[N]6 coordination geometry and possess greater thermal stability than their Si and Ge homologues. The nitrogen content of the adducts of up to 44 % exceed any SnIV compound known hitherto.