bluuebunny/crossref_metadata_2025_split huggingface dataset:
Degrading habitats and the effect of topographic complexity on risk assessment
Authors: McCormick Mark I. , Lönnstedt Oona M. 
Published: October 2013

AbstractTopographic complexity is a key component of habitats that influences communities by modulating the interactions among individuals that drive population processes such as recruitment, competition, and predation. A broad range of disturbance agents affect biological communities indirectly through their modifications to habitat complexity. Individuals that best judge the threat of predation within their environment and can trade‐off vigilance against behaviors that promote growth will be rewarded with the highest fitness. This study experimentally examined whether topographic habitat complexity affected the way a damselfish assessed predation risk using olfactory, visual, or combined cues. Fish had higher feeding rates in the low complexity environment. In a low complexity environment, damage‐released olfactory cues and visual cues of predators complemented each other in the prey's assessment of risk. However, where complexity was high and visual cues obscured, prey had lower feeding rates and relied more heavily on olfactory cues for risk assessment. Overall, fish appear to be more conservative in the high complexity treatment. Low complexity promoted extremes of behavior, with higher foraging activity but a greater response to predation threats compared with the high complexity treatment. The degree of flexibility that individuals and species have in their ability to adjust the balance of senses used in risk assessment will determine the extent to which organisms will tolerate modifications to their habitat through disturbance.
Molecular identification of the prey range of the invasiveAsian paper wasp
Authors: Ward Darren F. , Ramón‐Laca Ana 
Published: October 2013

AbstractThe prey range of the invasiveAsian paper wasp,Polistes chinensis antennalis, was studied using molecular diagnostics. Nests of paper wasps were collected from urban residential and salt marsh habitats, larvae were removed and dissected, andDNAin the gut of the paper wasp larvae was amplified and sequenced with cytochrome c oxidase subunit I (COI). Seventy percent of samples (211/299) yielded medium‐to high‐quality sequences, and prey identification was achieved usingBLASTsearches inBOLD. A total of 42 taxa were identified from 211 samples. Lepidoptera were the majority of prey, with 39 taxa from 91% of samples. Diptera was a relatively small component of prey (three taxa, 19 samples). Conclusive species‐level identification of prey was possible for 67% of samples, and genus‐level identification, for another 12% of samples. The composition of prey taken was different between the two habitats, with 2.5× more native prey species being taken in salt marsh compared with urban habitats. The results greatly extend the prey range of this invasive species. The technique is a more effective and efficient approach than relying on the collection of “prey balls”, or morphological identification of prey, for the study of paper wasps.
Nucleotide diversity of vernalization and flowering‐time‐related genes in a germplasm collection of meadow fescue (Festuca pratensis Huds. syn. Lolium pratense (Huds.) Darbysh.)
Authors: Shinozuka Hiroshi , Hand Melanie L. , Cogan Noel O. I. , Spangenberg German C. , Forster John W. 
Published: October 2013

AbstractIn plant species, control of flowering time is an important factor for adaptation to local natural environments. The Vrn1, CO, FT1 and CK2α genes are key components in the flowering‐specific signaling pathway of grass species. Meadow fescue is an agronomically important forage grass species, which is naturally distributed across Europe and Western Asia. In this study, meadow fescue flowering‐time‐related genes were resequenced to assess nucleotide diversity in European and Western Asian subpopulations. Identified sequence polymorphisms were then converted into PCR‐based molecular genetic markers, and a meadow fescue germplasm collection was genotyped to investigate global allelic variation. Lower nucleotide diversities were observed for the Vrn1 and CO orthologs, while relatively higher values were observed for the FT1 and casein kinase II α‐subunit (CK2α) orthologs. The nucleotide diversity for FT1 orthologs in the Western Asian subpopulation was significantly higher than those of the European subpopulation. Similarly, significant differences in nucleotide diversity for the remaining genes were observed between several combinations of subpopulation. The global allele distribution pattern was consistent with observed level of nucleotide diversity. These results suggested that the degree of purifying selection acting on the genes differs according to geographical location. As previously shown for model plant species, functional specificities of flowering‐time‐related genes may also vary according to environmental conditions.
Alterations to dam‐spill discharge influence sex‐specific activity, behaviour and passage success of migrating adult sockeye salmon
Authors: Burnett Nicholas J. , Hinch Scott G. , Donaldson Michael R. , Furey Nathan B. , Patterson David A. , Roscoe David W. , Cooke Steven J. 
Published: October 2013

ABSTRACTDelays in the freshwater spawning migrations of anadromous fishes at upstream barriers are well documented, but underlying mechanisms causing slowed migrations are seldom known. Using acoustic accelerometer transmitters and generalized linear models, we investigated how alterations in flow at a diversion dam in British Columbia, Canada, affected the activity, behaviour and passage success of a Fraser River sockeye salmon population (Oncorhynchus nerka). Spilling excess water through the radial gate of the dam decreased the attraction efficiency of a vertical‐slot fishway by 90% and increased delay below the dam by 2 h, which had adverse effects on passage. Relative to males, female sockeye salmon had significantly lower passage success (73% vs 94%), attraction efficiency (79% vs 100%) and passage efficiency (89% vs 94%) at a fishway, delayed longer in the dam tailrace (mean ± standard error (SE): 20·8 ± 4·1 h vs 14·6 ± 3·2 h), and resorted to anaerobic swimming efforts for a greater percentage of time (0–61·3% vs 0·7–2·7%). Given that the persistence of Pacific salmon populations relies on the spawning success of females, understanding how males and females vary in their response to modified flow regimes will improve the management of complex fish‐passage problems. Copyright © 2013 John Wiley & Sons, Ltd.
Self‐Assembly of Coordination Polymers from Volatile PdII and PbII β‐Diketonate Derivatives through Metallophilic Interactions
Authors: Krisyuk Vladislav V. , Baidina Iraida A. , Basova Tamara V. , Bulusheva Lyubov G. , Igumenov Igor K. 
Published: October 2013

AbstractNew dimetallic coordination polymers based on neutral metal β‐diketonate derivatives can be obtained by simple cocrystallization from organic solvents. X‐ray crystallography studies have been performed for the dimetallic complexes [trans‐Pd(ki)2]*[Pb(hfa)2] (1; ki = 2‐iminopentan‐4‐onate, hfa = 1,1,1,5,5,5‐hexafluoropentane‐2,4‐dionate), [cis‐Pd(ki)2]*[Pb(hfa)2] (2), and [trans‐Pd(tmha)2]*[Pb(hfa)2]2 (3; tmha = 2,2,6,6‐tetramethyl‐3‐iminoheptan‐5‐onate). The crystals of 1 and 3 are composed of chains of coordination polymers containing alternating molecules of the metal complexes. The crystals of 2 are composed of tetrametallic species. Directed noncovalent metal–metal interactions along with the bridging ligand atoms bind the coordination polymers of these heterometallic coordination compounds. Structural evidence is reported for the formation of PdII···PbII metallophilic interactions in a series of similar compounds. A comparison of the calculated and experimental IR spectra allowed determination of the absorption bands in the region 100–600 cm–1 that correspond to the cooperative vibrations of the metal atoms that result from such interactions. The steric and electronic factors of the chelate ligands can be used to design the architecture of these new coordination polymers.
Heteropolyacid‐Based Materials as Heterogeneous Photocatalysts
Authors: Marcì Giuseppe , García‐López Elisa I. , Palmisano Leonardo 
Published: October 2013

AbstractHeteropolyacids (HPAs) that are often used as heteropolyanions are cheap and stable compounds that have been extensively used as acid and oxidation catalysts as a result of their strong Brønsted acidity and ability to undergo multielectron‐transfer reactions. HPAs, which are very soluble in water and polar solvents, have been also used as homogeneous photocatalysts for the oxidation of organic substrates in the presence of oxygen, but their use in heterogeneous systems is by far desirable. Dispersing HPAs onto solid supports with high surface area is useful to increase their specific surface area and hence (photo)catalytic activity. Moreover, owing to the high energy gap between the HOMO and LUMO positions of the HPAs, these compounds are activated only by UV light. Consequently, only less than 5 % of the solar light can be used in photocatalytic reactions, which restricts the practical application of HPAs. This microreview is oriented to describe the reported literature on the use of HPA‐based materials as heterogeneous photocatalysts for environmental purposes, that is, for the complete or partial oxidation or reduction of organic molecules.
(2‐Fluoro‐2,2‐dinitroethyl)‐2,2,2‐trinitroethylnitramine: A Possible High‐Energy Dense Oxidizer
Authors: Klapötke Thomas M. , Krumm Burkhard , Rest Sebastian F. , Reynders Martin , Scharf Regina 
Published: October 2013

AbstractThe fluorine‐containing polynitro energetic molecule (2‐fluoro‐2,2‐dinitroethyl)‐2,2,2‐trinitroethylnitramine and the corresponding precursors were synthesized and investigated as potential high‐energy dense oxidizers. The compounds have been characterized by using various analytical methods, single‐crystal X‐ray diffraction, vibrational spectroscopy (IR and Raman), multinuclear NMR spectroscopy, elemental analysis, mass spectrometry, and differential scanning calorimetry (DSC) measurements. The suitability of the compounds as potential oxidizers in energetic formulations has been investigated. In addition, the heats of formation of the products were calculated with the program package Gaussian 09. Several detonation parameters such as the detonation pressure, velocity, energy, and temperature were computed using the EXPLO5 code. Furthermore, the sensitivity towards impact, friction, and electrical discharge was determined using the German Federal Institute for Materials Research and Testing (BAM) drophammer, a friction tester, as well as a small‐scale electrical discharge device.
Investigation of Magnetic Exchange Pathways in Heterotrinuclear Manganese(III) Schiff Base Complexes Involving Tetrathiocyanidoplatinate(II) Bridges
Authors: Nemec Ivan , Šilha Tomáš , Herchel Radovan , Trávníček Zdeněk 
Published: October 2013

AbstractThe first heterotrinuclear manganese(III) Schiff base complexes involving tetrathiocyanidoplatinum(II) bridges with the general formula [{MnIII(L4)(Solv)}2{μ‐PtII(SCN)4}] {for which L42– is a tetradentate dianionic Schiff base ligand; L412– = N,N′‐benzene‐bis(salicylideneiminate) dianion (1a), L422– = N,N′‐ethylene‐bis(salicylidenebenzeneiminate) dianion (1b), L432– = N,N′‐benzene‐bis(4‐aminodiethylenesalicylideneiminate) dianion (1c), and Solv = CH3OH (1a, 1b) or H2O (1c)} were synthesized and characterized. The two terminal [Mn(L4)(Solv)]+ subunits are covalently bridged by [Pt(SCN)4]2– moieties in a trans arrangement. The coordinated solvent (Solv) ligands form intermolecular hydrogen bonds with the phenolate oxygen atoms of the neighboring molecules, which results in supramolecular 1D chain structures. Extensive networks of weak noncovalent interactions stabilize the crystal structures of all the compounds; moreover, hydrogen bonding within the chains was identified as a dominant exchange pathway. Magnetic analyses including the zero‐field splitting term revealed that the antiferromagnetic exchange interaction is stronger for compounds involving water molecules as ligands [1c, J = –1.31(6) cm–1] than for those containing methanol molecules [1a, J = –0.530(9) cm–1; 1b, J = –0.467(7) cm–1]. DFT calculations at the B3LYP/def2‐TZVP level supported the experimental findings that dominant antiferromagnetic exchange paths proceed through hydrogen bonds associated with the Solv ligands, whereas the [Pt(SCN)4]2– bridges prevent effective magnetic exchange.
An Efficient Approach to Azolyl‐Substituted Steroids through Copper‐Catalyzed Ullmann C–N Coupling
Authors: Kotovshchikov Yury N. , Latyshev Gennadij V. , Lukashev Nikolay V. , Beletskaya Irina P. 
Published: October 2013

AbstractUllmann‐type C–N coupling of vinyliodides and nitrogen heterocycles has been shown to be a straightforward and highly efficient approach to azolyl‐substituted steroids. The amination reaction proved sensitive to steric effects exerted by the substituents in both iodide and heterocycle. The influence of reaction conditions (catalyst, base, solvent, and temperature) on conversion of the iodosteroid and the selectivity was investigated. The catalytic system comprising 10 mol‐% CuI and 20 mol‐% dipivaloylmethane with K2CO3 in dimethyl sulfoxide at 100 °C delivered the best result. The elaborated protocol has permitted iodosteroids with various substituted indoles, imidazoles, carbazole, indazole, and sec‐amides to be coupled, affording the corresponding azolyl‐substituted steroids in good to excellent yields.
N‐Heterocyclic Carbene–Betaine Interconversions: Tautomeric Equilibria of Imidazolium‐Indolates and Indole‐Substituted Imidazol‐2‐ylidenes
Authors: Pidlypnyi Nazar , Uhrner Fabian , Nieger Martin , Drafz Martin H. H. , Hübner Eike G. , Namyslo Jan C. , Schmidt Andreas 
Published: October 2013

AbstractIndol‐2‐yl‐hetarenium salts of imidazole, benzimidazole, imidazo[1,5‐a]pyridine, imidazo[1,2‐a]pyridine, (pyridin‐2‐yl)imidazole, and 2,5‐bis(imidazol‐1‐yl)pyridine were prepared. On deprotonation, hetarenium‐indolates were formed that belong to the subclass of ylides of heterocyclic mesomeric betaines. The stabilities of these ylides depend on the substitution pattern. The ylides are in tautomeric equilibrium with the N‐heterocyclic carbenes (indol‐2‐yl)imidazol‐2‐ylidenes, which were trapped as thiones on reaction with sulfur. The N‐heterocyclic carbene derived from imidazo[1,5‐a]pyridine could also be trapped as its zwitterionic borane adduct by reaction with triethylborane. Results of two single‐crystal X‐ray analyses and DFT calculations are presented.
Photoinduced Release of Neurotransmitter Amino Acids from Coumarin‐Fused Julolidine Ester Cages
Authors: Piloto Ana M. , Hungerford Graham , Costa Susana P. G. , Gonçalves M. Sameiro T. 
Published: October 2013

AbstractThe photoinduced release of several neurotransmitter amino acids (glycine, alanine, glutamic acid, β‐alanine and γ‐aminobutyric acid) was accomplished from ester cages based on a new photoremovable protecting group consisting of a coumarin built on the julolidine nucleus, namely a (11‐oxo‐2,3,5,6,7,11‐hexahydro‐1H‐pyrano[2,3‐f]pyrido[3,2,1‐ij]quinolin‐9‐yl)methyl group. Photolysis and steady‐state sensitization studies revealed that release of the active molecule occurred in short irradiation times at long wavelengths, with a very promising performance at 419 nm. Given the interest in the development of novel protecting groups that are cleavable with UV A or even visible radiation, it was found that a structural modification in the coumarin ring by assembly of a fused julolidine leads to a promising photolabile protecting group for organic synthesis and also for bioapplications.
Palladium‐Catalysed Synthesis of 9H‐Pyrrolo[1,2‐a]indol‐9‐ones and the Isomeric Indeno[2,1‐b]pyrrol‐8‐ones
Authors: Wang Shuyang , Yang Qinghua , Dong Jingjing , Li Changwei , Sun Li , Song Chuanjun , Chang Junbiao 
Published: October 2013

Abstract9H‐Pyrrolo[1,2‐a]indol‐9‐ones and isomeric indeno[2,1‐b]pyrrol‐8‐ones could be obtained in moderate to good isolated yields, by subjecting the same substrates, 2‐bromophenyl N‐tosyl‐2‐pyrrolyl ketones, to different palladium catalysts.
Phosphonate Analogues of Arabinose 5‐Phosphate: Putative Ligands for Arabinose 5‐Phosphate Isomerases
Authors: Gabrielli Luca , Airoldi Cristina , Sperandeo Paola , Gianera Serena , Polissi Alessandra , Nicotra Francesco , Cipolla Laura 
Published: October 2013

AbstractMetabolically stable arabinose 5‐phosphate analogues possessing phosphate mimetic groups at the 5‐position were synthesized and evaluated by saturation‐transfer‐difference (STD) NMR studies for their ability to interact with arabinose 5‐phosphate isomerase. Isosteric methylphosphonate 1 and (difluoromethyl)phosphonate 3 were recognised and bound by the catalytic pocket of the enzyme. The synthesized compounds were tested in vivo on E. coli and P. aeruginosa strains in order to evaluate their antibacterial activity.
Selective Reduction of Amino Allenephosphonates: Preparation of α‐Amino Vinylphosphonates
Authors: Adler Pauline , Gomes Filipe , Fadel Antoine , Rabasso Nicolas 
Published: October 2013

Abstractα‐Amino vinylphosphonates were prepared by chemo‐ and stereoselective reduction of α‐amino allenephosphonates. Our results showed that the substituents on the allene, phosphonate, and nitrogen moieties affected the stereoselectivity of the reduction. Z‐α‐Amino vinylphosphonates were prepared with good selectivities up to > 95:5.
An (Aminopyrimidinato)titanium Catalyst for the Hydroamination of Alkynes and Alkenes
Authors: Brahms Christian , Tholen Patrik , Saak Wolfgang , Doye Sven 
Published: October 2013

AbstractA new (aminopyrimidinato)titanium complex has been synthesised from inexpensive and easily accessible 2‐(tert‐butylamino)pyrimidine and [Ti(NMe2)4] and used as a catalyst for the intermolecular hydroamination of alkynes as well as the cyclization of aminoalkenes. The hydroamination reactions of 1‐phenylpropyne and terminal arylalkynes deliver the corresponding anti‐Markovnikov addition products with excellent yields and regioselectivities.
Perfluoroalkylated Bis(sulfilimine)s and Bis(sulfoximine)s by a Ritter‐Type Reaction
Authors: Pégot Bruce , Urban Céline , Diter Patrick , Magnier Emmanuel 
Published: October 2013

AbstractOur synthetic methodology, which was previously developed for the preparation of perfluoroalkyl sulfilimines by a reaction between fluorinated sulfoxides and nitriles, has been successfully extended to dinitriles. According to the reaction conditions, we can preferentially produce a cyano monosulfilimine or a bis(sulfilimine). New cyano thioethers have been synthesized through a rearrangement process. Mono‐ and bis(sulfilimine)s were also oxidized to afford the corresponding sulfoximines, which provide a direct route to potential new ligands for catalysis and new electrophilic perfluoroalkylating reagents.
Synthesis of CF3‐Substituted Olefins by Julia–Kocienski Olefination Using 2‐[(2,2,2‐Trifluoroethyl)sulfonyl]benzo[d]thiazole as Trifluoromethylation Agent
Authors: Hafner Andreas , Fischer Tobias S. , Bräse Stefan 
Published: October 2013

AbstractA modified Julia–Kocienski protocol was investigated for the synthesis of CF3‐substituted terminal olefins. By employing a simple one‐step procedure, aldehydes were converted into the corresponding CF3‐substituted olefins using 2‐[(2,2,2‐trifluoroethyl)sulfonyl]benzo[d]thiazole as the trifluoromethylation agent. This sulfone was prepared on a gram scale in two steps from inexpensive and commercially available trifluoroethanol. The Julia–Kocienski olefination tolerated various functional groups, and the trifluoromethylated olefins were obtained in good yields. However, the E/Z selectivity was strongly substrate dependent, and only moderate selectivities could be achieved.
Synthesis, Antiviral Evaluation, and Computational Studies of Cyclobutane and Cyclobutene L‐Nucleoside Analogues
Authors: Miralles‐Llumà Rosa , Figueras Antoni , Busqué Félix , Alvarez‐Larena Angel , Balzarini Jan , Figueredo Marta , Font Josep , Alibés Ramon , Maréchal Jean‐Didier 
Published: October 2013

AbstractThis paper describes the stereoselective synthesis of a series of functionalized cyclobutane and cyclobutene L‐nucleoside analogues featuring a methylene spacer between the carbocycle and the nucleobase. These L‐nucleoside analogues were subjected to comprehensive screening for antiviral activity. To obtain knowledge at the molecular structural level relevant for designing future analogues, the mechanism of action of these L‐nucleoside analogues as anti‐herpes simplex virus agents was investigated by computational approaches. In particular, protein–ligand docking calculations were used to rationalize the ability of the prodrug candidates to be activated. Docking experiments were performed on the three kinases involved in the activation process of thymine and guanine derivatives.
Transition‐Metal‐Free Synthesis of (E)‐Vinyl Sulfones from Vinyl Halides in Water
Authors: Liang Shuai , Zhang Ruo‐Yi , Wang Gao , Chen Shan‐Yong , Yu Xiao‐Qi 
Published: October 2013

AbstractA practical transition‐metal‐free procedure for the synthesis of (E)‐vinyl sulfones through the coupling of vinyl halides with sodium sulfinates in water is reported. The reaction is strongly influenced by the presence of acids, and the use of nBu4NBr promotes its efficiency.
Iron‐Catalyzed Three‐Component Synthesis of α‐Amino Acid Derivatives
Authors: Halli Juliette , Manolikakes Georg 
Published: October 2013

AbstractAn efficient, iron‐catalyzed, three‐component synthesis of arylglycines starting from readily available amides, glyoxalates, and arenes or heteroarenes has been developed. This method provides a versatile, atom‐economic, and cost‐effective route to arylglycines with water as the only byproduct. With carbamates as the amide component, various synthetically useful N‐protected arylglycine derivatives could be prepared.
Electrochemical Behavior of Gold Nanoparticles Generated In Situ on 3‐(1‐Imidazolyl)propyl‐silsesquioxane
Authors: Simon Ícaro A. , Vacaro Bernardo B. , Nunes Michael R. , Benvenutti Edilson V. , Dias Silvio L. P. , Gushikem Yoshitaka , Arguello Jacqueline 
Published: October 2013

AbstractGold nanoparticles of different morphologies have been synthesized on a silica‐based organic‐inorganic hybrid material for catalytic applications. The gold nanoparticles formations proceed through in situ chemical reduction of the AuCl4− anions previously adsorbed on 3‐(1‐imidazolyl)propyl‐silsesquioxane, which plays the role of substrate and stabilizer. Two distinct reducing agents, sodium citrate and sodium borohydride, were employed to generate gold nanoparticles of different sizes. UV‐vis diffuse reflectance as well as transmission electron microscopy were employed to evaluate the particle’s morphology. Modified carbon paste electrodes were prepared from these materials and their electrochemical behavior investigated using potassium ferrocyanide and 4‐nitrophenol as redox model compounds. Both AuNPs‐modified electrodes decreased the overpotential of 4‐nitrophenol reduction by around 90 mV compared to the unmodified electrode as evidenced by cyclic voltammetry experiment. However, the smaller diameter particles (borohydride‐reduced) produced more significant catalytic effect as a consequence of their large surface area. Regarding the sensing parameters, the sensitivity is higher for the borohydride‐reduced AuNPs while the values of limit of detection are of the same order of magnitude. Thus, the detection limit and sensitivity are 70.0±0.6 nM and 187 µA/mM for the citrate‐reduced AuNPs; and 75.0±2.2 nM and 238 µA/mM for the borohydride‐reduced AuNPs.