bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimating resource selection with count data
Authors: Nielson Ryan M. , Sawyer Hall 
Published: June 2013

AbstractResource selection functions (RSFs) are typically estimated by comparing covariates at a discrete set of “used” locations to those from an “available” set of locations. This RSF approach treats the response as binary and does not account for intensity of use among habitat units where locations were recorded. Advances in global positioning system (GPS) technology allow animal location data to be collected at fine spatiotemporal scales and have increased the size and correlation of data used in RSF analyses. We suggest that a more contemporary approach to analyzing such data is to model intensity of use, which can be estimated for one or more animals by relating the relative frequency of locations in a set of sampling units to the habitat characteristics of those units with count‐based regression and, in particular, negative binomial (NB) regression. We demonstrate this NB RSF approach with location data collected from 10 GPS‐collared Rocky Mountain elk (Cervus elaphus) in the Starkey Experimental Forest and Range enclosure. We discuss modeling assumptions and show how RSF estimation with NB regression can easily accommodate contemporary research needs, including: analysis of large GPS data sets, computational ease, accounting for among‐animal variation, and interpretation of model covariates. We recommend the NB approach because of its conceptual and computational simplicity, and the fact that estimates of intensity of use are unbiased in the face of temporally correlated animal location data.
Inferences of evolutionary history of a widely distributed mangrove species, Bruguiera gymnorrhiza, in the Indo‐West Pacific region
Authors: Urashi Chie , Teshima Kosuke M. , Minobe Sumiko , Koizumi Osamu , Inomata Nobuyuki 
Published: June 2013

AbstractInference of genetic structure and demographic history is fundamental issue in evolutionary biology. We examined the levels and patterns of genetic variation of a widespread mangrove species in the Indo‐West Pacific region, Bruguiera gymnorrhiza, using ten nuclear gene regions. Genetic variation of individual populations covering its distribution range was low, but as the entire species it was comparable to other plant species. Genetic differentiation among the investigated populations was high. They could be divided into two genetic clusters: the West and East clusters of the Malay Peninsula. Our results indicated that these two genetic clusters derived from their ancestral population whose effective size of which was much larger compared to the two extant clusters. The point estimate of speciation time between B. gymnorrhiza and Bruguiera sexangula was two times older than that of divergence time between the two clusters. Migration from the West cluster to the East cluster was much higher than the opposite direction but both estimated migration rates were low. The past Sundaland and/or the present Malay Peninsula are likely to prevent gene flow between the West and East clusters and function as a geographical or land barrier.
Luminescence in Functionalized Copper Thiolate Clusters – Synthesis and Structural Effects
Authors: Langer Robert , Yadav Munendra , Weinert Bastian , Fenske Dieter , Fuhr Olaf 
Published: June 2013

AbstractA series of luminescent polynuclear copper(I) phenyl thiolate clusters with functional groups in the organic ligand shell has been synthesized and characterized by single‐crystal X‐ray diffraction. Cluster compounds 1–5 with Me2N groups bound to the phenyl thiolate are described and feature different nuclearities and core geometries. The heptanuclear compound 6, which contains both phenyl thiolate and Me3SiO functionalized phenyl thiolate ligands, is an unusual example of a mixed thiolate cluster and exhibits a core almost identical to that of 5. The optical properties of these compounds, which range from binuclear complexes with large Cu···Cu distances to cluster molecules with seven copper atoms and relatively short Cu···Cu distances, have been investigated. Compounds 1–5 show strong absorption below 500 nm. The intense luminescence covers a wide range of the visible spectrum (1: green; 2 and 3: blue; 4 and 5: yellow). It seems likely that the optical transitions occur between orbitals of the thiol ligands and metal‐centered orbitals; for the species with short Cu···Cu distances (3–5), these interactions cause a further redshift of the spectra. In addition, the influence of functional groups on optical absorption and emission is shown by the two Cu7 clusters 5 and 6, which differ solely in the electron‐donating nature of their functional groups.
Preliminary Theoretical Insights into SmI2‐Mediated Reactions: Activation of Ketones in THF
Authors: Kefalidis Christos E , Perrin Lionel , Maron Laurent 
Published: June 2013

AbstractThe structure of samarium iodide in THF solution and its reactivity towards aromatic ketones has been studied by means of DFT calculations. A comparison between the X‐ray and DFT optimised structure of [SmI2(THF)3(η2‐MeOCH2H4OMe)] and [SmI2(THF)5]+ shows that the use of DFT‐B3PW91 in conjunction with the appropriate relativistic electron core potential is able to reproduce the structures of these complexes. In THF solution, the simulation of SmI2(THF)n complexes reveals that an equilibrium should exist between SmI2(THF)5, SmI2(THF)4, SmI2(THF)3 and dimetallic [SmI(μ‐I)(THF)2]2. The formation of SmI2(THF)2 and the dissociation of an iodide to yield [SmI (THF)n]+ is less likely to occur. A first estimation of the thermodynamics of ketone reduction by SmI2(THF)n is given and qualitative values compared with experiment are presented. Concerning the pinacolic coupling of ketones, a “key intermediate” based on experimental interpretation has been considered. Formation of this so‐called “Streitwiser dimer” is strongly endothermic with respect to the monomeric SmIII–OCPh2 radical anion adduct. A doubly reduced ketone sandwiched between two Sm centres is more likely to occur and is consistent with the overall pinacol coupling reaction.
Color and Brightness Tuning in Heteronuclear Lanthanide Terephthalate Coordination Polymers
Authors: Haquin Victor , Etienne Mael , Daiguebonne Carole , Freslon Stéphane , Calvez Guillaume , Bernot Kevin , Le Pollès Laurent , Ashbrook Sharon E. , Mitchell Martin R. , Bünzli Jean‐Claude , Eliseeva Svetlana V. , Guillou Olivier 
Published: June 2013

AbstractHeteronuclear lanthanide terephthalate coordination polymers with the general chemical formula [Ln2–2xLn′2x(bdc)3(H2O)4]∞, for which bdc2– symbolizes benzene‐1,4‐dicarboxylate (or terephthalate) and Ln and Ln′ represent trivalent rare earth ions, were synthesized and structurally characterized. Analysis of the Y/Lu compounds by 89Y and 13C solid‐state NMR spectroscopy was carried out, and the results support the hypothesis of randomly distributed lanthanide ions. The spectroscopic and colorimetric properties of this family of compounds were investigated in detail. The resulting data demonstrate that this series of compounds presents highly tunable luminescence properties and clearly indicate that intermetallic deactivation processes play an important role in the emission mechanism. Playing with intermetallic distances allows one to tune the color and the brightness of the lanthanide emission in these coordination polymers.
Regioselective 2‐Imino‐1,3‐thiazolidine vs. 2‐Imino‐1,3‐oxazolidine Formation from the Vicinal sec‐Amino Alcohol of Desosamine
Authors: Ištuk Zorica Marušić , Vujasinovi Ines , Čikoš Ana , Kragol Goran 
Published: June 2013

AbstractIn order to optimize Mukaiyama reagent‐induced cyclization of vicinal sec‐amino alcohols of desosamine origin towards exclusive formation of N′‐substituted‐2‐imino‐1,3‐thiazolidines via a thiocarbamoyl intermediate, the influence of reaction conditions was studied. A novel, mild, one‐pot, two‐step method was developed, and the formation of N′‐substituted‐2‐imino‐1,3‐oxazolidines as side products was minimized. The inversion of configuration at C‐2′ was unambiguously established using NMR‐based conformational analysis. A reaction mechanism was proposed. A test series of novel desosamine‐modified 14‐ and 15‐membered macrolides, bearing N′‐alkyl‐2‐imino‐1,3‐thiazolidines fused to the desosamine sugar were prepared.
Protocols for the Catalytic Oxidation of Primary Amines to Imines
Authors: Largeron Martine 
Published: June 2013

AbstractThe catalytic oxidation of amines to imines is of intense current interest, owing to the importance of imines as pivotal intermediates in the synthesis of fine chemicals and numerous biologically active compounds. Whereas considerable efforts had been made to develop efficient methods for the oxidation of secondary amines to imines, little attention had until recently been given to the oxidation of primary amines, probably because the generated imines are intermediate products that are easily dehydrogenated to nitriles. A surge of activity in this area originated with the discovery of new catalytic systems that allow the oxidation of primary amines to imines under green conditions. This microreview focuses on the major achievements during the last five years.
Photochemical and Thermal [2 + 2] Cycloaddition to Generate the Bicyclo[3.2.0]­hept­ane Core of Bielschowskysin
Authors: Farcet Jean‐Baptiste , Himmelbauer Martin , Mulzer Johann 
Published: June 2013

AbstractA bicyclic core fragment of the marine diterpenoid bielschowskysin has been synthesized. First, a large library of precursors for a photochemical [2 + 2] cycloaddition was prepared and tested, but with limited success. In the end, a thermal [2 + 2] cycloaddition followed by appropriate regio‐ and stereocontrolled functionalization efficiently gave access to the desired bicyclo[3.2.0]heptane core. An optimized route to this remarkable molecular structure is presented.
Rearrangements of Furan‐, Thiophene‐ and N‐Boc‐Pyrrole‐Derived Donor‐Acceptor Cyclopropanes: Scope and Limitations
Authors: Kaschel Johannes , Schneider Tobias F. , Schirmer Patrick , Maaß Christian , Stalke Dietmar , Werz Daniel B. 
Published: June 2013

AbstractRearrangements of furan‐, thiophene‐ and N‐Boc‐pyrrole‐derived donor–acceptor cyclopropanes initiated by Brønsted acids were investigated. Throughout the study, ketones or aldehydes were utilized as accepting moieties and oxygen, sulfur and Boc‐protected nitrogen were used as the donor atoms. Whether a ring‐enlargement and thus an annelation of a five‐membered ring, or a ring‐opening of the three‐membered ring followed by rearomatization to the parent heterocycles takes place strongly depends on the substitution pattern of the cyclopropane. Commonly, more substituted substrates led to annelation whereas less substituted substrates tend to undergo rearomatization. In general, good yields were obtained for starting materials with oxygen and nitrogen donors, whereas the reactions with sulfur as donor gave only poor yields.
Synthesis, Chiral Resolution, and Absolute Configuration of Dissymmetric 4,12‐Difunctionalized [2.2]Paracyclophanes
Authors: Meyer‐Eppler Georg , Vogelsang Elisabeth , Benkhäuser Christian , Schneider Andreas , Schnakenburg Gregor , Lützen Arne 
Published: June 2013

AbstractRacemic 4,12‐difunctionalized [2.2]paracyclophanes were synthesized and successfully resolved by (recycling) HPLC on a stationary CHIRALPAK IA phase at a semipreparative scale. Their absolute configurations were determined by X‐ray crystal structure analysis and/or by comparison of their specific optical rotations with literature data. These are valuable functionalized C2‐symmetric building blocks for the formation of more sophisticated V‐shaped, chiral molecular architectures, as demonstrated by some exploratory transformations.
Total Synthesis of the Hypermodified tRNA Nucleoside Epoxyqueuosine
Authors: Thoma Ines , Carell Thomas 
Published: June 2013

AbstractQueuosine is one of the most strongly modified nucleosides found in transferRNA (tRNA) of almost all species. Queuosine is found exclusively in the wooble position of the anticodon loop of several tRNA, where it is involved in tRNAAsp, tRNAAsn tRNAHis, and tRNATyr. The biosynthesis of queuosine is performed by prokaryotes, and eukaryotes are fully dependent on this external source. To investigate the interesting biosynthesis of the Q base, we report here the first total synthesis of the direct biosynthetic precursor oQ. By using LC–MS in combination with special E. coli growing conditions (no vitamin B12 in the medium) we confirm the structure of the oQ natural products.
Long‐Term Forecasting of Global Carbon Dioxide Emissions: Reducing Uncertainties Using a Per Capita Approach
Authors: Mckitrick Ross , Strazicich Mark C. , Lee Junsoo 
Published: June 2013

ABSTRACTGlobal CO2 emission forecasts span such a wide range as to yield little guidance for climate policy and analysis. But global per capita emissions appear to be better constrained than total emissions, which we argue has an economic justification. Trend stationarity of per capita emissions may provide a means of characterizing the relative likelihood of global forecasts. On data spanning 1950 to 2009 a unit root hypothesis allowing for endogenous structural breaks is rejected, but adding in the 2010 observation pushes the p‐value slightly over 0.1. Since structural breaks cannot be detected at the end of sample this may simply indicate a power problem. Using Monte Carlo simulations we conclude that the lower half of a well‐known suite of IPCC emission scenarios is more likely to occur than the upper half, and the top quartile is particularly difficult to justify. Copyright © 2013 John Wiley & Sons, Ltd.
The Role of High‐Frequency Intra‐daily Data, Daily Range and Implied Volatility in Multi‐period Value‐at‐Risk Forecasting
Authors: Louzis Dimitrios P. , Xanthopoulos‐Sisinis Spyros , Refenes Apostolos P. 
Published: June 2013

ABSTRACTThis paper assesses the informational content of alternative realized volatility estimators, daily range and implied volatility in multi‐period out‐of‐sample Value‐at‐Risk (VaR) predictions. We use the recently proposed Realized GARCH model combined with the skewed Student's t distribution for the innovations process and a Monte Carlo simulation approach in order to produce the multi‐period VaR estimates. Our empirical findings, based on the S&P 500 stock index, indicate that almost all realized and implied volatility measures can produce statistically and regulatory precise VaR forecasts across forecasting horizons, with the implied volatility being especially accurate in monthly VaR forecasts. The daily range produces inferior forecasting results in terms of regulatory accuracy and Basel II compliance. However, robust realized volatility measures, which are immune against microstructure noise bias or price jumps, generate superior VaR estimates in terms of capital efficiency, as they minimize the opportunity cost of capital and the Basel II regulatory capital. Copyright © 2013 John Wiley & Sons, Ltd.
Research into the functional components and antioxidant activities of North China rice wine (Ji Mo Lao Jiu)
Authors: He Shuai , Mao Xiangzhao , Liu Pei , Lin Hong , Du Zuyuan , Lv Ning , Han Jichen , Qiu Cuifang 
Published: June 2013

AbstractOver the last decade, considerable experimental evidence has supported the view that grape wine and South China rice wine are rich in diverse nutrients and have powerful antioxidant activity. However, little research has been carried out for North China rice wine, of which Ji Mo Lao Jiu (JMLJ) is the outstanding representative. In this study, the functional components and antioxidant activity of JMLJ were investigated. Twenty‐eight free amino acids were found in JMLJ, much more than that previously reported in other Chinese rice wines (16–21). Functional oligosaccharides (5290.222 mg/L), total phenols (722.431 ± 10.970 mg/L), and mineral elements (9) were rich in JMLJ. When compared with synthetic antioxidants, such as butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT), JMLJ showed effective 1,1‐diphenyl‐2‐picryl‐hydrazyl (DPPH) radical scavenging and reducing capacity. The results of this study lay the foundation for promoting the utilization of JMLJ and the development of North China rice wine in the food industry.
Erweiterte Einsatzbereiche von EPB‐Schilden
Authors: Budach Christoph , Thewes Markus 
Published: June 2013

AbstractZur Erweiterung der Einsatzbereiche von Erddruckschilden auf gemischtkörnige Lockergesteine mit geringem Feinanteil sowie auf grobkörnige Böden hat sich die Konditionierung des abgebauten Materials mit Schäumen, Polymeren und Feinstoffsuspensionen als effektiv erwiesen. Auf diese Weise können die Eigenschaften des Stützmediums in der Abbaukammer eines Erddruckschilds so verändert werden, dass z.B. die Fließfähigkeit sowie die Durchlässigkeit günstig beeinflusst werden. Bisherige Veröffentlichungen zu den Einsatzgrenzen von Erddruckschilden, insbesondere in grobkörnigen Böden, sind vielfach durch die empirische Auswertung von Baustellenerfahrungen geprägt. In den hier vorgestellten Untersuchungen erfolgte dagegen eine breite und systematische Variation von Kornverteilungen grob‐ und gemischtkörniger Böden, die mit Schäumen, Polymeren sowie Feinstoffsuspensionen konditioniert wurden. Die Laboruntersuchungen mit den konditionierten Böden betrafen insbesondere die Kriterien der Verarbeitbarkeit und der Wasserdurchlässigkeit. Unter Berücksichtigung praxisnaher Vorgaben für diese Kriterien konnte ein modifiziertes Kornverteilungsdiagramm für die Einsatzbereiche von Erddruckschilden entwickelt werden.Extended Application Ranges of EPB‐Shields. Soil conditioning for Earth‐Pressure‐Balance shield tunnelling with foams, polymers or high density slurries has proven to be an effective measure to extend the application ranges of EPB‐Shields towards mixed‐grained soils with a low content of fines and coarse‐grained soils. By conditioning, the properties of the support medium in the excavation chamber, which mainly consists of the excavated ground, can be changed in order to positively influence i.e. its deformability and permeability. Acknowledging existing results of research on EPB conditioning a new investigation programme was developed, which aimed at a broad and systematic variation of coarse soil types as well as conditioning agents. Based on the results of the laboratory research, a chart for the application ranges for EPB‐Shields using various conditioning agents was developed, which shows some significant differences to the existing empirical charts that by large are based on job site experience.
Topographical control of ocular cell types for tissue engineering
Authors: McHugh Kevin J. , Saint‐Geniez Magali , Tao Sarah L. 
Published: June 2013

AbstractVisual impairment affects over 285 million people worldwide and has a major impact on an individual's quality of life. Tissue engineering has the potential to increase the quality of life for many of these patients by preventing vision loss or restoring vision using cell‐based therapies. However, these strategies will require an understanding of the microenvironmental factors that influence cell behavior. The eye is a well‐organized organ whose structural complexity is essential for proper function. Interactions between ocular cells and their highly ordered extracellular matrix are necessary for maintaining key tissue properties including corneal transparency and retinal lamination. Therefore, it is not surprising that culturing these cells in vitro on traditional flat substrates result in irregular morphology. Instead, topographically patterned biomaterials better mimic native extracellular matrix and have been shown to elicit in vivo‐like morphology and gene expression which is essential for tissue engineering. Herein we review multiple methods for producing well‐controlled topography and discuss optimal biomaterial scaffold design for cells of the cornea, retina, and lens. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 101B: 1571–1584, 2013.
Cytotoxicity of adhesive systems of different hydrophilicities on cultured odontoblast‐like cells
Authors: Bianchi Luciana , Ribeiro Ana Paula Dias , de Oliveira Carrilho Marcela Rocha , Pashley David H. , de Souza Costa Carlos Alberto , Hebling Josimeri 
Published: June 2013

AbstractThis study evaluated the cytotoxicity of experimental adhesive systems (EASs) on odontoblast‐like cells. Paper discs (n = 132) were impregnated with 10 µL of each EAS—R1, R2, R3, R4, and R5 (in an ascending order of hydrophilicity), followed by photoactivation. R1 and R2 are nonsolvated hydrophobic blends, R3 represents a simplified etch‐and‐rinse adhesive system, and R4 and R5 represent simplified self‐etch adhesive systems. Discs were immersed in Dulbecco's modified Eagle's medium for 24 h to obtain eluates applied on MDPC‐23 cell cultures. No material was applied on discs used as control (R0). Cell viability [3‐(4,5‐dimethythiazol‐2‐yl)−2,5‐diphenyl tetrazolium bromide assay], total protein (TP) production, alkaline phosphatase (ALP) activity, type of cell death, and degree of monomer conversion Fourier transform infrared (%DC‐FTIR) were evaluated. Data were analyzed by Kruskal–Wallis and Mann–Whitney tests (α = 0.05). Considering R0 (control) as having 100% of cell viability, R1, R2, R3, R4, and R5 reduced the metabolic activity of cells by 36.4, 3.1, 0.2, 21.5, and 65.7%, respectively, but only R1 and R5 differed from R0. Comparing with R0, lower TP production was observed for R1, R4, and R5, while ALP activity decreased for R1 and R5. Necrotic cell death was predominant for all EASs, but only R1, R4, and R5 differed from R0. Only R5 presented a different apoptotic cell death ratio from R0. R1 presented the lowest %DC (ca. 37%), whereas R4 and R5 presented the highest (ca. 56%). In conclusion, R2 and R3 were not toxic to the MDPC‐23 cells, suggesting that the degree of hydrophilicity or %DC of the EASs alone were not responsible for their cytopathic effects. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 101B: 1498–1507, 2013.