bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lewis Base Catalyzed Aerobic Oxidative Intermolecular Azide–Zwitterion Cycloaddition
Authors: Li Wenjun , Wang Jian 
Published: October 2014

AbstractThe discovery of a novel aerobic oxidative intermolecular azide–zwitterion reaction catalyzed by an organocatalyst is presented. It is demonstrated that the merger of the Lewis base 1,8‐diazabicyclo[5.4.0]undec‐7‐ene and electron‐deficient olefins generates reactive zwitterion intermediates, which readily participate in cycloaddition reactions with an array of azides, thus providing facile entry to fully or highly substituted 1,2,3‐triazole frameworks. The reaction features an excellent substrate scope, and the products are obtained with high yields and excellent regioselectivities. It is demonstrated that some of these products can be transformed into pharmaceutically important agents. In addition to the experimental results, a detailed mechanistic survey is also provided, including MS studies rationalizing the origin of regioselective control.
Construction of a Highly Distorted Benzene Ring in a Double Helicene
Authors: Hashimoto Sigma , Nakatsuka Soichiro , Nakamura Masaharu , Hatakeyama Takuji 
Published: October 2014

AbstractA P‐fused double helicene consisting of a highly distorted benzene ring, with a bending angle of 23°, has been synthesized by a tandem intramolecular phospha‐Friedel–Crafts reaction. Despite the distortion and reduced aromaticity, the double helicene shows thermal and chemical stability. These are important features that make these compounds attractive for applications as a new C2‐symmetric bisphosphine ligand. The simple strategy proposed in this work can be used to prepare a diverse range of distorted molecules.
Pseudokontaktverschiebungen lokalisieren Eisen(III) in der zweikernigen Metallo‐β‐Laktamase IMP‐1
Authors: Carruthers Thomas J. , Carr Paul D. , Loh Choy‐Theng , Jackson Colin J. , Otting Gottfried 
Published: October 2014

AbstractHeterozweikernige Metalloenzyme bilden eine bedeutende Klasse von Metalloproteinen, bei denen jedoch die Bestimmung der Positionen der Metallionen schwierig sein kann. Hier beschreiben wir ein neues NMR‐Verfahren, das Pseudokontaktverschiebungen (PCS) nutzt, um die Position von Metallionen ohne Annahmen über die koordinierenden Liganden zu ermitteln. Die Methode wird anhand des zweikernigen [FeZn]‐Komplexes von IMP‐1 beschrieben. IMP‐1 ist ein Prototyp der Metallo‐β‐Laktamasen (MβL), die Resistenz gegen β‐Laktam‐Antibiotika bewirken. Eine versuchte Einkristall‐Röntgenstrukturanalyse wurde durch teilweise Oxidation des Proteins während der Kristallisation beeinträchtigt. Mit [GaZn]‐IMP‐1 als diamagnetischer Referenz ermittelten die PCSs eindeutig die Eisen‐Bindungsstelle in frischen Proben von [FeZn]‐IMP‐1, obwohl die beiden Metallzentren weniger als 3.8 Å auseinander liegen und das Eisen als High‐Spin‐Fe3+ vorliegt, welches nur kleine PCSs erzeugt. [FeZn]‐MβLs könnten bedeutende pharmazeutische Zielproteine darstellen, da [FeZn]‐IMP‐1 enzymatisch aktiv ist und schon bei geringen Konzentrationen an Fe3+ auftritt.
A Fully Synthetic Four‐Component Antitumor Vaccine Consisting of a Mucin Glycopeptide Antigen Combined with Three Different T‐Helper‐Cell Epitopes
Authors: Palitzsch Björn , Hartmann Sebastian , Stergiou Natascha , Glaffig Markus , Schmitt Edgar , Kunz Horst 
Published: October 2014

AbstractIn a new concept of fully synthetic vaccines, the role of T‐helper cells is emphasized. Here, a synthetic antitumor vaccine consisting of a diglycosylated tumor‐associated MUC1 glycopeptide as the B‐cell epitope was covalently cross‐linked with three different T‐helper‐cell epitopes via squaric acid ligation of two linear (glyco)peptides. In mice this four‐component vaccine administered without external immune‐stimulating promoters elicit titers of MUC1‐specific antibodies that were about eight times higher than those induced by a vaccine containing only one T‐helper‐cell epitope. The promising results indicate that multiple activation of different T‐helper cells is useful for applications in which increased immunogenicity is required. In personalized medicine, in particular, this flexible construction of a vaccine can serve as a role model, for example, when T‐helper‐cell epitopes are needed that match human leukocyte antigens (HLA) in different patients.
Ghosts of the coast: global extinction risk and conservation of sawfishes
Authors: Dulvy Nicholas K. , Davidson Lindsay N. K. , Kyne Peter M. , Simpfendorfer Colin A. , Harrison Lucy R. , Carlson John K. , Fordham Sonja V. 
Published: October 2014

Abstract

Sawfish are arguably the world's most imperilled marine fishes. All five species are classified as highly threatened with extinction: three are Critically Endangered (smalltooth sawfish Pristis pectinata, largetooth sawfish Pristis pristis, and green sawfish Pristis zijsron); two are Endangered (narrow sawfish Anoxypristis cuspidata, and dwarf sawfish Pristis clavata).
Sawfishes are threatened primarily due to a combination of their low intrinsic rates of population increase, high catchability in fisheries, and high value. Sawfishes are among the world's largest marine fishes, and they are caught by a wide range of fishing gears owing to their tooth‐studded rostra being easily entangled. Sawfish fins are some of the most valuable for shark fin soup, and their rostra have long been traded as curios. In addition, they inhabit shallow coastal waters, estuaries, and rivers of the tropics and subtropics, down to a maximum depth rarely exceeding 100 m and are associated with threatened mangrove and seagrass habitats.
Historically, sawfishes were distributed in the coastal waters of 90 countries and territories. Over the past century, their geographic distribution has been greatly diminished. For example, the smalltooth sawfish is now found in <20% of its former range. Globally, sawfishes are now entirely absent from 20 countries; 43 countries have lost at least one species.
Sawfishes are legally protected, to some degree, in 16 of the 90 range states. These safeguards encompass, on average, 81% of their Extant distribution; however, the quality and breadth of protection varies dramatically across countries and species. Smalltooth sawfish currently has the least amount of such coverage of only half (49%) of Extant distribution.
The global conservation strategy specifies actions to protect sawfish and their habitats. Such actions are urgently warranted to avoid global extinction and to restore robust populations for the benefit of coastal ecosystem function and biodiversity.
© 2014 The Authors. Aquatic Conservation: Marine and Freshwater Ecosystems published by John Wiley & Sons, Ltd.
Decreased Bacterial Diversity Characterizes the Altered Gut Microbiota in Patients With Psoriatic Arthritis, Resembling Dysbiosis in Inflammatory Bowel Disease
Authors: Scher Jose U. , Ubeda Carles , Artacho Alejandro , Attur Mukundan , Isaac Sandrine , Reddy Soumya M. , Marmon Shoshana , Neimann Andrea , Brusca Samuel , Patel Tejas , Manasson Julia , Pamer Eric G. , Littman Dan R. , Abramson Steven B. 
Published: October 2014

ObjectiveTo characterize the diversity and taxonomic relative abundance of the gut microbiota in patients with never‐treated, recent‐onset psoriatic arthritis (PsA).MethodsHigh‐throughput 16S ribosomal RNA pyrosequencing was utilized to compare the community composition of gut microbiota in patients with PsA (n = 16), patients with psoriasis of the skin (n = 15), and healthy, matched control subjects (n = 17). Samples were further assessed for the presence and levels of fecal and serum secretory IgA (sIgA), proinflammatory proteins, and fatty acids.ResultsThe gut microbiota observed in patients with PsA and patients with skin psoriasis was less diverse when compared to that in healthy controls. This could be attributed to the reduced presence of several taxa. Samples from both patient groups showed a relative decrease in abundance of Coprococcus species, while samples from PsA patients were also characterized by a significant reduction in Akkermansia, Ruminococcus, and Pseudobutyrivibrio. Supernatants of fecal samples from PsA patients revealed an increase in sIgA levels and decrease in RANKL levels. Analysis of fatty acids revealed low fecal quantities of hexanoate and heptanoate in both patients with PsA and patients with psoriasis.ConclusionPatients with PsA and patients with skin psoriasis had a lower relative abundance of multiple intestinal bacteria. Although some genera were concomitantly decreased in both conditions, PsA samples had a lower abundance of reportedly beneficial taxa. This gut microbiota profile in PsA was similar to that previously described in patients with inflammatory bowel disease and was associated with changes in specific inflammatory proteins unique to this group, and distinct from that in patients with skin psoriasis and healthy controls. Thus, the role of the gut microbiome in the continuum of psoriasis–PsA pathogenesis and the associated immune response merits further study.
Multifunctional Carbon Nanohorn Complexes for Cancer Treatment
Authors: Chechetka Svetlana A. , Pichon Benoit , Zhang Minfang , Yudasaka Masako , Bégin‐Colin Sylvie , Bianco Alberto , Miyako Eijiro 
Published: October 2014

AbstractMultifunctional carbon nanohorn (CNH) complexes were synthesized using oxidized CNH, magnetite (MAG) nanoparticles, and polyethyleneimine (PEI). The ferromagnetic MAG nanoparticles were loaded onto CNH (MAG‐CNH) using iron(II) acetate and subsequent heat treatment. Chemical functionalization of the MAG‐CNH complexes with PEI improved their water‐dispersibility and allowed further conjugation with a fluorophore. The application of an external magnetic field significantly intensified the targeted vectorization of CNH complexes into human cervical cancer (HeLa) cells. Following cell uptake, laser irradiation of the cells showed a significant enhancement in the photothermal effects of CNHs leading to cell death. We have confirmed that the photothermal properties and ferromagnetic characteristics of CNH complexes show efficient cell elimination. The present study is an essential step toward the development of an innovative cancer therapy and a highly sensitive detection of cancer cells at the single‐cell level.
Robust Optimal Disturbance Observer Design for the Non‐Minimum Phase System
Authors: Wang Lu , Su Jianbo 
Published: October 2014

AbstractIn this paper, a design strategy of robust disturbance observer is proposed systematically for stable non‐minimum phase systems. This strategy synthesizes the internal and robust stability, relative order and mixed sensitivity design requirements together to establish the optimization function. The optimal solution is obtained by standard H∞ control theory under the condition of guarantying the presented requirements. Simulation results of a rotary mechanical system show the effectiveness of the proposed strategy.
Detection of transient high frequency optical oscillations of the flare star YZ CMin
Authors: Contadakis M.E. , Avgoloupis S.J. , Seiradakis J.H. 
Published: October 2014

AbstractIn this paper we present the results of the analysis of the B ‐light curve for the flares of the red dwarf YZ CMin (dM4.5e), which were observed on February of 2002, with the help of the 30‐inch Cassegrain telescope of the Stephanion Observatory, Greece. Discrete Fourier Transform analysis and the use of the Brownian Walk noise enable us to estimate the proper random noise and detect possible weak transient optical oscillations. Our results indicate that: (1) Transient high frequency oscillations occur during the flare event and during the quiet‐star phase as well. (2) The observed frequencies range between 0.0083 Hz (period 2 min) and 0.3 Hz (period 3 s) is not rigorously bounded. The phenomenon is most pronounced during the flare state. (3) During the flare state: (a) Oscillations with period 2 to 1.5 min, 60 s, 11 s, 7.5 s, and 4 s appear around the maximum light state and persist during the whole flare state, (b) from the flare maximum phase on, a progressive increase of oscillations with periods 30 s, 20 s down to 4.0 s is markedly indicated, and (c) at the end of the flare only the oscillation of the pre‐flare state do remain. Our observations are consistent with the phenomenology of impulsively exited oscillations on a coronal magnetic loop and subsequent chromospheric heating by electronic flux at the foot of the loop or/and by soft X‐ray coronal emission. Our observation give evidence that more than one impulsive events may occur in the course of an observed flare (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Environmental dependence of the presence of active galactic nuclei (AGNs) in the volume‐limited Main galaxy samples of SDSS DR6
Authors: Deng X.‐F. , Xin Y. , Wu P. , Jiang P. , Ding Y.‐P. , Qi X.‐P. 
Published: October 2014

AbstractUsing two volume‐limited Main galaxy samples of the Sloan Digital Sky Survey Data Release 6 (SDSS DR6) above and below the value of M∗︁r, we have explored the environmental dependence of the AGN fraction. It is found that the fraction of AGNs declines substantially with increasing local density in the luminous volume‐limited sample, but in the faint volume‐limited sample this change is very weak. We also note that the presence of AGNs is not correlated with the stellar mass (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
MUCHFUSS – Massive Unseen Companions to Hot Faint Underluminous Stars from SDSS
Authors: Geier S. , Schaffenroth V. , Hirsch H. , Tillich A. , Heber U. , Maxted P.F.L. , Østensen R.H. , Barlow B.N. , O'Toole S.J. , Kupfer T. , Marsh T. , Gänsicke B. , Napiwotzki R. , Cordes O. , Müller S. , Classen L. , Ziegerer E. , Drechsel H. 
Published: October 2014

AbstractThe project Massive Unseen Companions to Hot Faint Underluminous Stars from SDSS (MUCHFUSS) aims at finding hot subdwarf stars with massive compact companions (white dwarfs with masses M > 1.0 M⊙, neutron stars or black holes). The existence of such systems is predicted by binary evolution calculations and some candidate systems have been found. We identified ≃1100 hot subdwarf stars from the Sloan Digital Sky Survey (SDSS). Stars with high velocities have been reobserved and individual SDSS spectra have been analysed. About 70 radial velocity variable subdwarfs have been selected as good candidates for follow‐up time resolved spectroscopy to derive orbital parameters and photometric follow‐up to search for features like eclipses in the light curves. Up to now we found nine close binary sdBs with short orbital periods ranging from ≃0.07 d to 1.5 d. Two of them are eclipsing binaries with companions that are most likely of substellar nature (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Debris disks as seen by Herschel/DUNES
Authors: Löhne T. , Eiroa C. , Augereau J.‐C. , Ertel S. , Marshall J.P. , Mora A. , Absil O. , Stapelfeldt K. , Thébault P. , Bayo A. , del Burgo C. , Danchi W. , Krivov A.V. , Lebreton J. , Letawe G. , Magain P. , Maldonado J. , Montesinos B. , Pilbratt G.L. , White G.J. , Wolf S. 
Published: October 2014

AbstractThe far‐infrared excesses produced by debris disks are common features of stellar systems. These disks are thought to contain solids ranging from micron‐sized dust to planetesimals. Naturally, their formation and evolution are linked to those of potential planets. With this motivation, the Herschel open time key programme DUNES (DUst around NEarby Stars) aims at further characterising known debris disks and discovering new ones in the regime explored by the Herschel space observatory. On the one hand, in their survey of 133 nearby FGK stars, DUNES discovered a class of extremely cold and faint debris disks, different from well‐known disks such as the one around Vega in that their inferred typical grain sizes are rather large, indicating low dynamical excitation and low collision rates. On the other hand, for the more massive disk around the sun‐like star HD 207129, well‐resolved PACS images confirmed the ring‐liked structure seen in HST images and provided valuable information for an in‐depth study and benchmark for models. Employing both models for power‐law fitting and collisional evolution we found the disk around HD 207129 to feature low collision rates and large grains, as well. Transport by means of Poynting‐Robertson drag likely plays a role in replenishing the dust seen closer to the star, inside of the ring. The inner edge is therefore rather smooth and the contribution from the extended halo of barely bound grains is small. Both slowly self‐stirring and planetary perturbations could potentially have formed and shaped this disk (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The promises of Gaia
Authors: Prusti T. 
Published: October 2014

AbstractGaia is an ESA mission performing astrometry, photometry and spectroscopy of about one billion objects in our Milky Way galaxy and beyond. The extent and content of the Gaia Catalogues will enable major progress to be made in many fields of galactic and stellar astronomy. The prime industrial contractor, EADS Astrium, Toulouse, is manufacturing the spacecraft and its payload for launch in 2013. Parallel to the space segment development the ground segment is getting ready as well. The Mission Operations Centre in Darmstadt, the Science Operations Centre in Madrid and the Gaia Data Processing and Analysis Consortium having members in many institutes across Europe are all tackling the challenges imposed by the high scientific requirements of the mission. The Gaia observing principles, overall status and scientific performances will be outlined (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Galactic thin and thick disk
Authors: Steinmetz M. 
Published: October 2014

AbstractThe ongoing large spectroscopic surveys of the Milky Way such as SEGUE and RAVE have enabled us to take a fresh look at the structure of the Galactic thin and thick disks, and how their structure fits within the framework of structure formation via hierarchical clustering. In this article I will summarize some recent results mainly based in the RAVE survey with respect to the structure of the Galactic disks, their possible origin as well as indications of substructure and asymmetries (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Torun catalogue of 6.7 GHz methanol masers
Authors: Szymczak M. , Wolak P. , Bartkiewicz A. , Borkowski K.M. 
Published: October 2014

AbstractWe report the observations of 289 methanol maser sources at 6.7 GHz obtained over a two month period with the Torun 32 m telescope. The data form a catalogue of all objects north of δ = –22° brighter than 7.5 Jy in the peak emission. The positions of sub‐arcsecond accuracy are updated for 76 % of the objects. We find that about one third of the sources show changes in the peak fluxes by a factor of two or more on time scales of 8.5–9.5 years (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Composite spectra: XVIII HR 6497, a triple system containing a baffling double secondary
Authors: Griffin R.E.M. , Griffin R.F. 
Published: October 2014

AbstractWe present a full description of, and parameters for, the component stars in the triple‐lined composite‐spectrum system HR 6497. Both the outer and the inner orbits have already been computed with fair accuracy, but the improved orbits resulting from this new analysis have precisions that are up to an order of magnitude tighter. By applying the proven technique of spectral subtraction to a large sample of new, high‐quality spectra we separate the spectra of the inner pair cleanly for the first time, and show that it has characteristics which cannot be explained at all easily by conventional models. Since the inner pair are separated by only 4 times their own radii, we expect their rotations to be synchronized to their orbital revolution, or close to 28 km/s, but in fact they have almost no visible rotation at all. The Mg II line at λ 4481 Å, itself a close doublet with a separation of 0.2 Å, is clearly resolved in the spectra of both components of the inner system. Such resolution is extremely rare in our experience, and we are unable to suggest a satisfactory explanation for it (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Principles of high‐dimensional data visualization in astronomy
Authors: Goodman A.A. 
Published: October 2014

AbstractAstronomical researchers often think of analysis and visualization as separate tasks. In the case of high‐dimensional data sets, though, interactive exploratory data visualization can give far more insight than an approach where data processing and statistical analysis are followed, rather than accompanied, by visualization. This paper attempts to charts a course toward “linked view” systems, where multiple views of high‐dimensional data sets update live as a researcher selects, highlights, or otherwise manipulates, one of several open views. For example, imagine a researcher looking at a 3D volume visualization of simulated or observed data, and simultaneously viewing statistical displays of the data set's properties (such as an x ‐y plot of temperature vs. velocity, or a histogram of vorticities). Then, imagine that when the researcher selects an interesting group of points in any one of these displays, that the same points become a highlighted subset in all other open displays. Selections can be graphical or algorithmic, and they can be combined, and saved. For tabular (ASCII) data, this kind of analysis has long been possible, even though it has been under‐used in astronomy. The bigger issue for astronomy and other “high‐dimensional” fields, though, is that no extant system allows for full integration of images and data cubes within a linked‐view environment. The paper concludes its history and analysis of the present situation with suggestions that look toward cooperatively‐developed open‐source modular software as a way to create an evolving, flexible, high‐dimensional, linked‐view visualization environment useful in astro‐physical research (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Collisions of comets and meteoroids: The post Stardust‐NExT discussion
Authors: Gronkowski P. , Wesolowski M. 
Published: October 2014

AbstractThe paper considers results of collisions between comets and meteoroids. We re‐discuss the five different approaches to estimate the sizes of holes created during such collisions. The results of the Deep Impact and the Stardust‐NExT missions to comet 9P/Temple 1 are applied to the estimation of these methods. We use the observed amount of ejected mass, the jump of brightness of the comet 9P/Tempel 1 as well as the diameter of the excavated crater. In the paper the simple way of estimation of impact consequences by use of the conception of the fragmentation energy of comet is also discussed. The numerical calculations were carried out for reasonable assumed values of a large range of cometary characteristics. The main conclusion of this paper confirms a general presumption that the main factor which determines the size of the impact crater on the comet 9P/Tempel 1 is the kinetic energy of impactor and strength or fragmentation energy of cometary material. In the considered case the gravitation of a comet has a minor meaning (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)