bluuebunny/crossref_metadata_2025_split huggingface dataset:
Theoretical Design of cis‐Bis(imido)uranium Iodides – Electronic Structures and Spectroscopic Properties
Authors: Lv Chun‐Mei , Pan Ling‐Chao , Pan Qing‐Jiang , Guo Yuan‐Ru , Zhang Hong‐Xing 
Published: September 2014

AbstractTo understand the structural and electronic properties of uranium complexes, the cis‐bis(imido)uranium iodides cis‐[U(NPh)2(THF)3I2] (3Ph) and cis‐[U(NPh)2(THF)2I2] (2Ph) have been designed, and their structures and properties have been calculated by density functional theory (DFT) and time‐dependent DFT. Four isomers (3Ph1, 3Ph2, 2Ph1, 2Ph2) were addressed in the study; these isomers have the structural feature that one iodide atom is trans to one imido group in the axial direction, and the other iodine atom is cis to the other imido group in the equatorial plane. The total system energies, geometry parameters, and vibrational spectra were similar among the respective isomers. Analyses of the electronic structures in tetrahydrofuran solution revealed that these isomeric complexes show mixed π(U=N) and π(Ph) character for the highest occupied molecular orbital (HOMO) and HOMO–1; the lone pairs of electrons of the iodine atom are dominant in the energetically lower occupied orbitals. U(f)‐type orbitals contribute to the low‐lying unoccupied orbitals, as has been generally accepted for analogous hexavalent trans‐dioxouranium complexes. Three main absorption peaks were observed for 3Ph1/3Ph2 and 2Ph1/2Ph2 from time‐dependent long‐range‐corrected functional calculations. The first one originates from the π(U=N) bonds and the phenyl groups, and the third is related to character of the iodine atoms [σ(U–I) and π(I)]; combined π(I) and π(U=N) character is attributed to the middle peak. We also calculated the experimentally known trans‐U(NPh)2(THF)3I2 (trans‐3Ph). The comparison of trans‐3Ph, 3Ph1, and 3Ph2 indicates that the cis/trans isomerism has a relatively large effect on their structural and electronic properties.
Revisiting the Synthesis of 4,6‐Difluorobenzofuroxan: A Study of Its Reactivity and Access to Fluorinated Quinoxaline Oxides
Authors: Jovené Cyril , Jacquet Morgane , Marrot Jérome , Bourdreux Flavien , Kletsky Mikhail E. , Burov Oleg N. , Gonçalves Anne‐Marie , Goumont Régis 
Published: September 2014

AbstractNew quinoxaline 1,4‐dioxide derivatives have been synthesized from novel fluorinated benzofuroxans such as 4‐fluorobenzofuroxan, which is prepared for the first time. Furthermore, the preparation 4,6‐difluorobenzofuroxan has been revisited because we were unable to reproduce the reported synthetic method. Several synthetic pathways have thus been investigated, and the optimal way to prepare this disubstituted benzofuroxan was from the 3,5‐difluoro‐2‐nitroaniline. The various synthetic attempts have allowed the isolation of interesting new compounds such as hydroxybenzotriazole‐like heterocycles or benzoquinone 2‐diazide. In the latter case, our study reveals some interesting features in the mechanism of their formation. The first structural elucidation of benzoquinone 2‐diazide through an X‐ray crystallographic study is also reported. This study has unambiguously shown that benzoquinone 2‐diazide can be involved in Diels–Alder reactions. The first case of a reaction involving a nitro‐substituted benzoquinone 2‐diazide and cyclopentadiene is also reported. To understand better the influence of the fluorine atoms on the reactivity of benzofuroxans and benzofurazans, a wide array of new fluorinated heterocycles were synthesized together with some already known compounds. This has enabled an extensive investigation of their electrophilic behavior to be undertaken through a theoretical and an electrochemical study. From these studies, it could be deduced that the replacement of nitro groups by fluorine atoms results in a significant decrease in the electrophilic character of benzofuroxan. Nevertheless, these compounds could undergo SNAr processes, leading to new functionalized heterocycles. The first examples of aromatic nucleophilic substitution of fluorine with these compounds are also described.
Efficient Synthesis of 1,4,7‐Triazacyclononane and 1,4,7‐Triazacyclononane‐Based Bifunctional Chelators for Bioconjugation
Authors: Désogère Pauline , Rousselin Yoann , Poty Sophie , Bernhard Claire , Goze Christine , Boschetti Frédéric , Denat Franck 
Published: September 2014

AbstractThe reaction of diethylenetriamine with chloroacetaldehyde yielded a bicyclic aminal intermediate for the synthesis of 1,4,7‐triazacyclononane (TACN), a macrocyclic polyamine the derivatives of which find applications as catalysts, bleaching agents, and chelators for medical imaging. This new synthetic protocol outperforms the synthetic methods described so far because it does not involve any cyclization step. Moreover, this aminal intermediate allowed access to a new family of TACN derivatives functionalized on the carbon skeleton, for example, C‐aminomethyl‐TACN. This novel compound is a precursor of valuable bifunctional chelating agents for nuclear medicine, in particular, for the preparation of PET imaging agents after bioconjugation and metallation with 68Ga or 64Cu.
Reagent‐Controlled Cyclization–Deprotection Reaction to Yield either Fluorenes or Benzochromenes
Authors: Killander Dan , Sterner Olov 
Published: September 2014

AbstractCompounds with benzochromene and fluorene structures are common in nature and society, and they can have potentially useful biological activities. In this paper, conditions for the selective preparation of either a benzochromene or a fluorene from the same starting material are described. The procedure uses a reagent‐controlled cyclization–demethylation to give the benzochromene, or an intramolecular Friedel–Crafts‐type alkylation to give the fluorene.
Asymmetric Evans syn‐Aldol Reactions of Terpene‐Derived Enals: Scope and Limitations
Authors: Kriening Sebastian , Evagelou Athanasios , Claasen Birgit , Baro Angelika , Laschat Sabine 
Published: September 2014

AbstractThe (E)‐ and (Z)‐terpene‐based aldehydes 6b and 6c with a silyl ether function in the γ‐position were prepared and investigated in boron‐mediated asymmetric Evans aldol reactions. Screening experiments of chiral N‐acylated oxazolidinones 7, which are conveniently accessible from 5‐methyl‐5‐hexenoic acid and Evans oxazolidinone auxiliaries, with various boron triflates and terpenoid neral (Z)‐6a as aldehyde component, provided conditions in which highly selective formation of syn‐aldol adduct 5a occurred and competing C=C double bond isomerization to 10 was completely suppressed. Applying the optimized conditions to O‐silylated aldehydes 6b and 6c and N‐acyloxazolidinone derivative (R)‐7a confirmed the syn‐selectivity and gave the appropriate products syn‐5b,c and syn‐21b,c in good yields. In the case of neral‐derived syn adduct 5a, the configuration of the new stereogenic centers C‐2/C‐3 could be assigned as (2R,3S).
Lipase‐Catalyzed Synthesis of Substituted Phenylacetamides: Hammett Analysis and Computational Study of the Enzymatic Aminolysis
Authors: García Liñares Guadalupe , Arroyo Mañez Pau , Baldessari Alicia 
Published: September 2014

AbstractA series of hydroxy‐, methoxy‐, and nitrophenylacetamides was synthesized by enzyme catalysis. The 28 new products were obtained through a lipase‐catalyzed two‐step reaction in very good to excellent yield. In the case of nitro derivatives, a one‐pot, two‐step methodology allowed the desired products to be obtained in high yields. The influence of various reaction parameters in the lipase‐catalyzed reactions, such as enzyme source, nucleophile (alcohol or amine)/substrate ratio, enzyme/substrate ratio, solvent and temperature were studied. It was observed that nitro‐substituted phenylacetates were more reactive in the aminolysis reaction than phenylacetates substituted with a hydroxyl group. To study this substituent effect, a Hammett analysis and the determination of the ρ parameter were carried out. Moreover, a computational study was applied to the most representative systems, performing an exploration of the potential energy surface for the catalyzed and noncatalyzed aminolysis reaction for nitro‐ and hydroxyphenylacetates. Both analysis showed that the presence of a strongly electron‐attracting group favors the activity of the enzyme, in complete agreement with the experimental results of the enzymatic catalysis.
A General Continuous Flow Method for Palladium Catalysed Carbonylation Reactions Using Single and Multiple Tube‐in‐Tube Gas‐Liquid Microreactors
Authors: Gross Ulrike , Koos Peter , O'Brien Matthew , Polyzos Anastasios , Ley Steven V. 
Published: September 2014

AbstractA series of continuous flow chemistry processes that facilitate the palladium‐catalysed carbonylation of aryl and vinyl iodides and aryl bromides with a range of alkoxy, hydroxy and amino nucleophiles is reported. Harnessing a semipermeable Teflon® AF‐2400 Tube‐in‐Tube assembly, these reactors permit the controlled transport of carbon monoxide into solution at elevated pressure to generate homogeneous flow streams, avoiding some potential issues associated with segmented flow gas‐liquid reactors. As the volume of pressurised gas contained within the device is low, the hazards associated with this are potentially mitigated relative to comparable batch processes. We also show how the incorporation of a second in‐line gas‐flow reactor allows for the sequential introduction of two gases (carbon monoxide and a gaseous nucleophile) into the reaction stream.
Six Peroxide Groups in One Molecule – Synthesis of Nine‐Membered Bicyclic Silyl Peroxides
Authors: Arzumanyan Ashot V. , Terent'ev Alexander O. , Novikov Roman A. , Lakhtin Valentin G. , Chernyshev Vladimir V. , Fitch Andrew N. , Nikishin Gennady I. 
Published: September 2014

AbstractCompounds containing two nine‐membered peroxide rings bridged by an ethane, ethene, or ethyne group were synthesized by the reactions of 1,2‐bis[dichloro(alkyl)silyl]ethanes, (E)‐1,2‐bis[dichloro(methyl)silyl]ethene, or 1,2‐bis[dichloro(methyl)silyl]ethyne with 1,1′‐dihydroperoxydicycloalkyl peroxides. Each ring is formed by the replacement of two geminal chlorine atoms at the silicon atom with the hydroperoxide groups of one peroxide molecule. The cyclization is regioselective. The possible 12‐membered bicyclic peroxide products are not produced. Unexpectedly, the peroxides are extremely explosive. The reactions of 1,2‐bis[dichloro(alkyl)silyl]ethanes with 1,1‐dihydroperoxy‐tert‐butylcyclohexane give only bicyclic peroxides containing two six‐membered rings also through the replacement of two geminal chlorine atoms at the silicon atom by the hydroperoxide groups of one dihydroperoxide molecule.
Reconsidering remap methods
Authors: Rider William J. 
Published: September 2014

SUMMARYMethods for discretizing remap are often based on algorithms developed for hyperbolic conservation laws. Because its introduction in 1977 Van Leer's monotonicity‐preserving piecewise linear method and its extensions have been ubiquitous in remap “Van Leer's fourth paper in his series “Towards the Ultimate””. In that 1977 paper, Van Leer introduced another five algorithms, which largely have not been used for remap despite the observation that the piecewise linear method had the least favorable theoretical properties. This adoption parallels the algorithmic choices in other related fields. Two factors have led to the lack of attraction to the five algorithms: the simplicity and effectiveness of the piecewise linear method and complications in practical implementation of the other methods. Plainly stated, Van Leer's piecewise linear method enabled ALE methods to move forward by providing a high‐resolution, monotonicity‐preserving remap. As a cell‐centered scheme, the extension to remap was straightforward. Several factors may be conspiring to reconsider these methods anew: computing architectures are more favorable toward more floating point intensive methods, methods lacking data movement, and 30 years of experience in devising nonlinear stability mechanisms (i.e., limiters). In particular, one of the methods blends characteristics of finite volume and finite difference methods together in an ingenious manner that has exceptional numerical properties and should be considered as a viable alternative to the ubiquitous piecewise linear method. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.
Investigating Injury Occurrence in Motor Vehicle Collision Using Artificial Neural Networks
Authors: Liu Dahai , Solomon Desmond , Hardy Leon 
Published: September 2014

AbstractVehicle collisions amount to a significant loss of life in America. Upward of 30,000 lives are lost each year in the United States alone. Hundreds of millions of dollars are spent each year on vehicle safety and roadway design in the United States, and many studies have been conducted on the causal factors for vehicle collisions. This study used artificial neural networks as a means to predict the occurrence of injury of a vehicle collision. The objective was to classify the levels of the “injury occurrence” in vehicle collisions, given certain input variables, including demographic and environmental factors involved in crashes. Using Neural Ware's Predict software, a back‐propagation neural network model was constructed, trained, tested, and validated using data from the 2006 and 2007 Florida Traffic Crash Database. The neural network's computational power was iteratively increased by adding hidden layers to boost its predicting power until the performance began to plateau. Classification rates as well as Kolmogorov‐Smirnov (K‐S) statistical analysis were used to validate the model. A sensitivity analysis was then applied to find the level of contribution that the input variables had on the injury occurrence. Accident severity, number of lanes, and road surface conditions were found to have the most positive impacts on the injury occurrence. The implications of the study are discussed at the end of the article.
Skin absorption of six performance amines used in metalworking fluids
Authors: Roux Lauriane N. , Brooks James D. , Yeatts James L. , Baynes Ronald E. 
Published: September 2014

AbstractEvery year, 10 million workers are exposed to metalworking fluids (MWFs) that may be toxic. There are four types of MWFs: neat oils and three water‐based MWFs (soluble oil, semisynthetic and synthetic), which are diluted with water and whose composition varies according to the mineral oils ratio. MWFs also contain various additives. To determine the absorption of six amines used as corrosion inhibitors and biocides in MWFs, porcine skin flow‐through diffusion cell experiments were conducted with hydrophilic ethanolamines (mono‐, di‐ and triethanolamine, MEA, DEA and TEA respectively) and a mixture of lipophilic amines (dibutylethanolamine, dicyclohexylamine and diphenylamine). The six amines were dosed in four vehicles (water and three generic water‐based MWF formulations) and analyzed using a scintillation counter or gas chromatography/mass spectrometry. These 24 h studies showed that dermal absorption significantly (P < 0.05) increased from water for the six amines (e.g. 1.15 ± 0.29% dose; DEA in water) compared to other formulations (e.g. 0.13 ± 0.01% dose; DEA in semisynthetic MWF) and absorption was greatest for dibutylethanolamine in all the formulations. The soluble oil formulation tended to increase the dermal absorption of the hydrophilic amines. The permeability coefficient was significantly higher (P < 0.05) with TEA relative to the other hydrophilic amines (e.g. 4.22 × 10–4 ± 0.53 × 10–4 cm h–1 [TEA in synthetic MWF] vs. 1.23 × 10–4 ± 0.10 × 10–4 cm h–1 [MEA in synthetic MWF]), except for MEA in soluble oil formulation. Future research will confirm these findings in an in vivo pig model along with dermatotoxicity studies. These results should help MWF industries choose safer additives for their formulations to protect the health of metalworkers. Copyright © 2014 John Wiley & Sons, Ltd.
Perturbation of cytosolic calcium by 2‐aminoethoxydiphenyl borate and caffeine affects zebrafish myofibril alignment
Authors: Wu Hsin‐Ju , Fong Tsorng‐Harn , Chen Shen‐Liang , Wei Jen‐Cheng , Wang I‐Jong , Wen Chi‐Chung , Chang Chao‐Yuan , Chen Xing‐Guang , Chen Wei‐Yu , Chen Hui‐Min , Horng Juin‐Lin , Wang Yun‐Hsin , Chen Yau‐Hung 
Published: September 2014

AbstractThe objective of the current study was to investigate the effects of Ca2+ levels on myofibril alignment during zebrafish embryogenesis. To investigate how altered cytoplasmic Ca2+ levels affect myofibril alignment, we exposed zebrafish embryos to 2‐aminothoxyldiphenyl borate (2‐APB; an inositol 1,4,5‐trisphosphate receptor inhibitor that reduces cytosolic Ca2+ levels) and caffeine (a ryanodine receptor activator that enhances cytosolic Ca2+ levels). The results demonstrated that the most evident changes in zebrafish embryos treated with 2‐APB were shorter body length, curved trunk and malformed somite boundary. In contrast, such malformed phenotypes were evident neither in untreated controls nor in caffeine‐treated embryos. Subtle morphological changes, including changes in muscle fibers, F‐actin and ultrastructures were easily observed by staining with specific monoclonal antibodies (F59 and α‐laminin), fluorescent probes (phalloidin) and by transmission electron microscopy. Our data suggested that: (1) the exposure to 2‐APB and/or caffeine led to myofibril misalignment; (2) 2‐APB‐treated embryos displayed split and short myofibril phenotypes, whereas muscle fibers from caffeine‐treated embryos were twisted and wavy; and (3) zebrafish embryos co‐exposed to 2‐APB and caffeine resulted in normal myofibril alignment. In conclusion, we proposed that cytosolic Ca2+ is important for myogenesis, particularly for myofibril alignment. Copyright © 2014 John Wiley & Sons, Ltd.
A comparison of fruit quality parameters of wild bilberry (Vaccinium myrtillus L.) growing at different locations
Authors: Mikulic‐Petkovsek Maja , Schmitzer Valentina , Slatnar Ana , Stampar Franci , Veberic Robert 
Published: September 2014

AbstractBACKGROUNDAs a part of the ongoing interest in nutritional and nutraceutical properties of locally produced fruits, the aim of the article was to determine sugars, organic acids, polyphenols and antioxidant capacity of wild bilberries grown in Slovenia. Primary and secondary metabolite composition of bilberry fruit was compared among six phyto‐climatic conditions, differing in photosynthetic active radiation and light intensity.RESULTSThree sugars were quantified in bilberry fruit, the predominant being fructose and glucose, along with five organic acids. Bilberry fruit contained high levels of anthocyanins (cyanidin, delphinidin, malvidin, petunidin and peonidin glycosides), hydroxycinnamic acid derivatives and low levels of flavonol glycosides (mainly quercetin and myricetin glycosides), flavan‐3‐ols, proanthocyanidins and iridoids. The results of the study indicate that bilberries growing in sites with high photosynthetic active radiation (PAR) contained higher levels of total sugars, anthocyanins, flavonols and hydroxycinnamic acids and lower levels of organic acids compared with bilberry fruit from low‐light locations. Consequently, total phenolic content and antioxidative capacity of the fruit from high‐PAR locations were significantly increased.CONCLUSIONBilberries from different natural habitats differ significantly in the quantity of sugars, organic acids and phenolic compounds. Our results contribute to a fuller understanding of the relationships between environmental factors and accumulation of primary and secondary metabolites in bilberry fruits. © 2014 Society of Chemical Industry
Numerical computations of rock dissolution and geomechanical effects for CO2 geological storage
Authors: Wojtacki K. , Lewandowska J. , Gouze Ph. , Lipkowski A. 
Published: September 2014

SummaryThe paper is motivated by the long‐term safety analysis of the CO2 geological storage. We present a methodology for the assessment of the geomechanical impact of progressive rock dissolution. The method is based on the use of X‐ray tomography and the numerical dissolution technique. The influence of evolution of the microstructure on the macroscopic properties of the rock is analysed by using periodic homogenization method. The numerical computations show progressive degradation of all components of the stiffness (orthotropic) tensor. Moreover, the evolution of associated mass transfer properties (as tortuosity and conductivity tensors), by using the periodic homogenization method, is also calculated. The correlation between the mechanical parameters and the transfer properties during the dissolution process is presented. The results show that the highest increase of the hydraulic conductivity (in direction Y) is not associated with the highest decrease of Young modulus in this direction. Moreover, the highest decrease of Young modulus (in the direction X) is not associated with percolation in this direction. Finally, an incremental law to calculate settlement, in case of a rock with evolving microstructure, is proposed. The solution of the macroscopic settlement problem under constant stress and drained conditions showed that the geomechanical effects of the rock dissolution are rather limited. Copyright © 2014 John Wiley & Sons, Ltd.
Epstein–Barr virus‐encoded EBNA1 and ZEBRA: targets for therapeutic strategies against EBV‐carrying cancers
Authors: Daskalogianni Chrysoula , Pyndiah Slovénie , Apcher Sébastien , Mazars Anne , Manoury Bénédicte , Ammari Nisrine , Nylander Karin , Voisset Cécile , Blondel Marc , Fåhraeus Robin 
Published: September 2014

AbstractThe EBV‐encoded EBNA1 was first discovered 40 years ago, approximately 10 years after the presence of EBV had been demonstrated in Burkitt's lymphoma cells. It took another 10 years before the functions of EBNA1 in maintaining the viral genome were revealed, and it has since been shown to be an essential viral factor expressed in all EBV‐carrying cells. Apart from serving to maintain the viral episome and to control viral replication and gene expression, EBNA1 also harbours a cis‐acting mechanism that allows virus‐carrying host cells to evade the immune system. This relates to a particular glycine–alanine repeat (GAr) within EBNA1 that has the capacity to suppress antigen presentation to the major histocompatibility complex (MHC) class I pathway. We discuss the role of the GAr sequence at the level of mRNA translation initiation, rather than at the protein level, as at least part of the mechanism to avoid MHC presentation. Interfering with this mechanism has become the focus of the development of immune‐based therapies against EBV‐carrying cancers, and some lead compounds that affect translation of GAr‐carrying mRNAs have been identified. In addition, we describe the EBV‐encoded ZEBRA factor and the switch from the latent to the lytic cycle as an alternative virus‐specific target for treating EBV‐carrying cancers. Understanding the molecular mechanisms of how EBNA1 and ZEBRA interfere with cellular pathways not only opens new therapeutic approaches but continues to reveal new cell‐biological insights on the interplay between host and virus. This review is a tale of discoveries relating to how EBNA1 and ZEBRA have emerged as targets for specific cancer therapies against EBV‐carrying diseases, and serves as an illustration of how mRNA translation can play roles in future immune‐based strategies to target viral disease. Copyright © 2014 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.