bluuebunny/crossref_metadata_2025_split huggingface dataset:
Catalyst‐Free and Catalysed Addition of P(O)–H Bonds to Allenyl/Alkynyl‐Phosphonates and ‐Phosphane Oxides: Use of a Robust, Recoverable Dinuclear Palladium(I) Catalyst
Authors: Srinivas Venu , Balaraman E. , Sajna K. V. , Kumara Swamy K. C. 
Published: June 2011

AbstractAn effective, recoverable, dinuclear palladium(I) catalyst [(OCH2CMe2CH2O)PSPd(PPh3)]2 has been explored and compared with other traditional palladium catalysts (e.g., [Pd(PPh3)4]) in the phosphonylation/phosphanylation ofallenes (OCH2CMe2CH2O)P(O)CH=C=CH2 (1), Ph2P(O)CH=C=CH2 (2), (EtO)2P(O)CH=C=CH2 (3) (OCH2CMe2CH2O)P(O)CH=C=CMe2 (4), Ph2P(O)CH=C=CMe2 (5), (OCH2CMe2CH2O)P(O)C(Ph)=C=CH2 (6) and Ph2P(O)C(Ph)=C=CH2 (7). The phosphonylation/phosphanylation, in general, occurred at the carbon β to the phosphorus atom, but the concomitant proton addition took place at the α or γ positions leading to either allyl‐ or vinyl‐phosphonates. The use of P(nBu)3 as catalyst led to geminal and bis‐phosphonylation/phosphanylation with less substituted =CH2 terminal allenes 1 and 2. In conjunction with the use of the corresponding isomeric alkynes 8 and 9, as many as five different types of phosphonylated products have been synthesized. The reactions with the more substituted allenes 4–7 gave single products in most cases. Several examples of catalyst‐free, solvent‐free phosphanylation reactions are also described. The reactivity of the phosphonylating/phosphanylating agents was found to be (OCH2CMe2CH2O)P(O)H (10) < (OCH2CMe2CH2O)P(S)H (11) < Ph2P(O)H (12) ≈ Ph2P(S)H (13). The catalytic activity of the recoverable dinuclear palladium(I) complex [(OCH2CMe2CH2O)PSPd(PPh3)]2 (14), which poses interesting questions about the mechanistic pathway, is briefly highlighted. Structures of the dinuclear palladium(I) catalyst 14 and the key products were determined by X‐ray crystallography.
Ruthenium(II)‐Catalyzed Asymmetric Transfer Hydrogenation Using Unsymmetrical Vicinal Diamine‐Based Ligands: Dramatic Substituent Effect on Catalyst Efficiency
Authors: Zhang Bo , Wang Hui , Lin Guo‐Qiang , Xu Ming‐Hua 
Published: June 2011

AbstractThe use of unsymmetrical vicinal diamines as ligands for Ru‐catalyzed asymmetric transfer hydrogenation is described. With a SmI2‐mediated cross‐coupling protocol, a series of enantiomerically pure unsymmetrical vicinal diamines were readily prepared and examined in the asymmetric transfer hydrogenation. It was found that an aromatic substituent on the carbon bearing the –NHTs group and a bulky alkyl substituent on the other side, are both very important for the effectiveness of the ligand, suggesting that the substituent has a dramatic effect on the catalyst efficiency. With ligand 8, excellent enantioselectivities that are comparable to N‐tosyl‐1,2‐diphenylethane‐1,2‐diamine (TsDPEN) were achieved. The results provide some helpful information on the mechanism of Ru‐catalyzed asymmetric transfer hydrogenation.
Site‐Selective Synthesis of Arylated Indenones by Suzuki–Miyaura Cross‐Coupling Reactions of 2,3,5‐Tribromoinden‐1‐one
Authors: Zinad Dhafer Saber , Hussain Munawar , Villinger Alexander , Langer Peter 
Published: June 2011

AbstractThe first transition‐metal‐catalyzed cross‐coupling reactions of 2,3,5‐tribromo‐1H‐inden‐1‐one are reported. The Suzuki–Miyaura reaction of 2,3,5‐tribromo‐1H‐inden‐1‐one with three equivalents of arylboronic acid gave 2,3,5‐triaryl‐1H‐inden‐1‐ones. The reaction with one and two equivalents of arylboronic acid gave 2,5‐dibromo‐3‐aryl‐1H‐inden‐1‐ones and 5‐bromo‐2,3‐diaryl‐1H‐inden‐1‐ones, respectively, with very good site‐selectivity. The one‐pot reaction of 2,3,5‐tribromo‐1H‐inden‐1‐one with one equivalent of two different arylboronic acids afforded 5‐bromo‐2,3‐diaryl‐1H‐inden‐1‐ones containing two different terminal aryl groups. Other one‐pot reactions allowed the synthesis of 2,3,5‐triaryl‐1H‐inden‐1‐ones containing different aryl groups.
Organocatalyzed Aziridination of α‐Branched Enals: Enantioselective Synthesis of Aziridines with a Quaternary Stereo­center
Authors: Desmarchelier Alaric , Pereira de Sant'Ana Danilo , Terrasson Vincent , Campagne Jean Marc , Moreau Xavier , Greck Christine , Marcia de Figueiredo Renata 
Published: June 2011

AbstractOrganocatalytic access to N‐tosylaziridines catalyzed by diarylprolinol trimethylsilyl ether [Ar = 3,5‐(CF3)2C6H3] starting from different α‐substituted‐α,β‐unsaturated aldehydes is described. The products were obtained in good yields (up to 86 %) and enantioselectivities (up to 90 % ee) and could rapidly be transformed under various conditions, including ring opening, to afford useful small molecules possessing not only the aziridine and aldehyde moieties but also other functionalities such as alcohol, acid, ester, or amino alcohol.
Synthesis of Novel Iminosugar‐Based Trehalase Inhibitors by Cross‐Metathesis Reactions
Authors: Bini Davide , Forcella Matilde , Cipolla Laura , Fusi Paola , Matassini Camilla , Cardona Francesca 
Published: June 2011

AbstractThe synthesis of a novel class of trehalase inhibitors composed of iminopyranose or iminofuranose residues linked at the pseudoanomeric carbon through an alkyl chain is described. A set of six novel compounds was prepared by the same reaction sequence involving the Grubbs Ru–carbene‐catalyzed cross‐metathesis (CM) of different N‐Cbz‐protected allyl C‐iminoglycosides as the key step in homo‐ or heterodimerization reactions. The target products, obtained with the CM reaction, were fully hydrogenated by catalytic hydrogenolysis, and preliminary biological screening of the products as inhibitors of commercially available porcine trehalase was performed.
Stereoselective Strecker and Carbamate Annulation Methodology for the Synthesis of 1‐Amino‐1,2,5‐trideoxy‐2,5‐imino‐L‐iditol
Authors: Win‐Mason Anna L. , Dangerfield Emma M. , Tyler Peter C. , Stocker Bridget L. , Timmer Mattie S. M. 
Published: June 2011

AbstractAn efficient and highly stereoselective synthesis of L‐ido‐aminoiminosugar 3 has been described. Key in the synthesis is the application of a diastereoselective Strecker reaction and the extension of our carbamate annulation methodology to protected and functionalized alkenylamines. In addition, the identification of the primary iodide as a key intermediate during the carbamate annulation reaction provides insight into the mechanism of this reaction.
Embarrassment: The ingroup–outgroup audience effect in faux pas situations
Authors: Eller Anja , Koschate Miriam , Gilson Kim‐Michelle 
Published: June 2011

AbstractEmbarrassment arises when we reveal an apparent flaw of the self in front of others, for instance, in a faux pas situation. An audience is crucial for embarrassment, but the group membership of the audience has not yet been studied. According to the social identity approach, we assign more importance to evaluations by ingroup than by outgroup members, particularly when we identify highly, and the outgroup is of lower status. A pilot study (N = 30) showed that embarrassment correlated positively with group membership of the audience and with identification. Studies 1 to 3 presented participants with several faux pas scenarios. In Study 1 (between‐participants design; N = 75), participants reported higher embarrassment in ingroup (Norwegian) and equal‐status outgroup (Swedish) conditions than in a lower‐status outgroup condition (Polish). In Study 2 (within‐participants design; N = 135), participants reported higher embarrassment when they imagined the audience to be other Scots (ingroup) than Americans or Poles (outgroups), particularly when they perceived the outgroup to be lower in status. In Study 3 (between‐participants design; N = 59), high identifiers but not low identifiers showed the expected ingroup–outgroup audience effect. Implications for intergroup relations are discussed. Key Message: Embarrassment following faux pas situations depends on the group membership of the audience, relative status of the audience and ingroup identification. Copyright © 2011 John Wiley & Sons, Ltd.
Tree establishment on bars in low‐order gravel‐bed mountain streams
Authors: Charron Isabelle , Johnson Edward A. , Martin Y. E. 
Published: June 2011

ABSTRACTIn many large alluvial rivers, trees often recruit and survive along laterally accreted sediments on bars. This produces a gradient of tree ages and composition with distance from the active channel. However, in low‐order, gravel‐bed mountain streams, such as the stream investigated in this study, it is suggested that vertical accretion results in sediment deposition patterns on bars that are often highly patchy. Consequently, tree species and ages are also heterogeneously distributed, rather than having distinct linear or arcuate banding patterns with distance from the channel. In addition, overall age patterns of trees on these bars follow the distribution of floods, with numerous young trees and few older trees. Recruitment is fairly continuous on these bars and is not correlated with high water years, suggesting that even flows close to bankfull levels are capable of transporting fine sediment to the bars on which trees establish. This pattern of sediment deposition/erosion and the resulting tree recruitment and survival seem to be a result of valley confinement and the lack of lateral accretion in these smaller, mountainous channels. Copyright © 2011 John Wiley & Sons, Ltd.
Lavender and peppermint essential oils as effective mushroom tyrosinase inhibitors: a basic study
Authors: Fiocco Daniela , Fiorentino Daniela , Frabboni Laura , Benvenuti Stefania , Orlandini Giulia , Pellati Federica , Gallone Anna 
Published: June 2011

ABSTRACTScreening and characterization of novel tyrosinase inhibitors is useful for applications in food technology, cosmetics and medicine. The hydrodistilled essential oils from lavender Lavandula spica L. and peppermint Mentha x piperita L. were investigated for tyrosinase inhibitory activity. Their composition was assessed by gas chromatography–mass spectrometry. Both oils inhibited mushroom tyrosinase in a dose dependent manner. The IC50 values were estimated, kinetics were analysed and Ki values were determined. Our results indicate that lavender and peppermint essential oils may be promising herbal ingredients for developing depigmenting agents in clinical, cosmetic and industrial processes. Copyright © 2011 John Wiley & Sons, Ltd.
Robust design in aerodynamics using third‐order sensitivity analysis based on discrete adjoint. Application to quasi‐1D flows
Authors: Papoutsis‐Kiachagias E. M. , Papadimitriou D. I. , Giannakoglou K. C. 
Published: June 2011

SUMMARYIn this paper, the second‐order second moment approach, coupled with an adjoint‐based steepest descent algorithm, for the solution of the so‐called robust design problem in aerodynamics is proposed. Because the objective function for the robust design problem comprises first‐order and second‐order sensitivity derivatives with respect to the environmental parameters, the application of a gradient‐based method , which requires the sensitivities of this function with respect to the design variables, calls for the computation of third‐order mixed derivatives. To compute these derivatives with the minimum CPU cost, a combination of the direct differentiation and the discrete adjoint variable method is proposed. This is presented for the first time in the relevant literature and is the most efficient among other possible schemes on condition that the design variables are much more than the environmental ones; this is definitely true in most engineering design problems. The proposed approach was used for the robust design of a duct, assuming a quasi‐1D flow model; the coordinates of the Bézier control points parameterizing the duct shape are used as design variables, whereas the outlet Mach number and the Darcy–Weisbach friction coefficient are used as environmental ones. The extension to 2D and 3D flow problems, after developing the corresponding direct differentiation and adjoint variable methods and software, is straightforward. Copyright © 2011 John Wiley & Sons, Ltd.
Channel movement and erosion response to rainfall variability in southeast Australia
Authors: Hancock G. R. , Coulthard T. J. 
Published: June 2011

AbstractIntrinsic and extrinsic forces on the catchment and stream channel network drive morphological change. Separating individual forcings is difficult given the complexity of such nonlinear systems. Here a modelling approach is used to investigate the sensitivity of channel position and movement under a series of realistic rainfall scenarios for a catchment in southeastern Australia. The results demonstrate the sensitivity of the catchment to different rainfall patterns and how relatively small changes in rainfall can lead to much larger sediment outputs revealing sensitivity to subtle changes in climate. Channel movement occurs as an avulsion. This is the first time such a process has been observed and modelled in an ephemeral stream environment and demonstrates fluvial geomorphic change at human time scales. Human intervention by rock lining channels was demonstrated to prevent the movement of the main channel. Overall the CAESAR landscape evolution and erosion model used in this study is able to replicate both erosion rates and the variation in past channel movement. The modelling suggests that any landscape change is based on both internal and external forcing and that landscape history also plays a significant role. Here, we demonstrate the potential to quantify many of the nonlinearities and thresholds in soil‐mantled catchments using a landscape evolution model. Copyright © 2011 John Wiley & Sons, Ltd.
Changes and challenges in 20 years of research into the development of executive functions
Authors: Hughes Claire 
Published: June 2011

AbstractThis review of 20 years of developmental research on Executive Functions (EF) offers a broad‐brushstroke picture that touches on multiple issues including: (i) findings from typical and atypical groups, from infancy to adolescence; (ii) advances in assessment tools and in statistical analysis; (iii) the interplay between EF and other cognitive systems (e.g. those involved in children's developing understanding of mind, and in their processing of reward signals); (iv) integration of cognitive and neuroscience perspectives on EF; and (v) environmental factors that have either a positive influence (e.g. training/intervention programmes; parental scaffolding) or a negative influence (e.g. maltreatment, neglect, traumatic brain injury) on EF. Of the several themes to emerge from this review, two are particularly important; these concern the need to adopt developmental perspectives and the potential importance for intervention work of research on social influences on EF. Specifically, the review highlights both developmental continuities (e.g. in the correlates of EF) and contrasts (e.g. in the nature of EF and its neural substrates) and calls for research that compares developmental trajectories for EF in different groups (e.g. children with autism versus ADHD). In addition, findings from both family‐based research and randomized controlled trials of school‐based interventions highlight the importance of environmental influences on EF and so support the development of interventions to promote EF and hence improve children's academic and social outcomes. Copyright © 2011 John Wiley & Sons, Ltd.
Water order profiles on phospholipid/cholesterol membrane bilayer surfaces
Authors: Robinson David , Besley Nicholas A. , O'shea Paul , Hirst Jonathan D. 
Published: June 2011

AbstractWater is pivotal in the stabilization of macromolecular biological structures, although the dynamic ensemble structure of water near to molecular surfaces has yet to be fully understood. We show, through molecular simulation and fluorescence measurements, that water at the membrane surface is substantially more ordered than bulk water, due to a loss of hydrogen bonding between water molecules, coupled with an alignment of lipid and water dipole moments. Ordering of the water leads to a gradient in the effective dielectric permittivity, which is evident in both the molecular simulations and the fluorescence measurements. A lower effective dielectric permittivity was correlated with a decreasing degree of hydrogen bonding over the same spatial range. The water molecules closest to the lipid headgroup oxygen atoms form hydrogen bonds which exhibit a mean lifetime of 6.3 ps, compared with a mean lifetime of water‐water hydrogen bonds of less than 2 ps. Membranes made up purely of phosphatidylcholine (PC) were compared with those made with a PC/cholesterol ratio relevant to cell membranes. Clear differences were found between these membrane configurations. These observations point to molecular structural differences in the surface environments of membranes and may underlie regional differences in the surface biophysical properties of membrane microdomains. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011.
The influence of cerium ion concentrations on the characteristics of hybrid films obtained on AA2024‐T3 aluminum alloy
Authors: Malfatti C. F. , Menezes T. L. , Radtke C. , Esteban J. , Ansart F. , Bonino J. P. 
Published: June 2011

AbstractThis work aimed to study the corrosion behavior of AA2024‐T3 aluminum alloy substrates pre‐treated with 3 glicidoxypropyltrimethoxysilane (GPTMS) silane layers doped with different cerium ion concentrations. The withdrawal speed of substrates from the sol was 20 cm · min−1. The hybrid films were obtained by dip‐coating process and analyzed by scanning electron microscopy (SEM) and energy dispersive spectroscopy, Rutherford scattering spectroscopy (RBS), salt spray test, and electrochemical analyses. The correlation among the results obtained from different analyses was very good and indicated that the addition of Ce ion in the hybrid coating contributed to the corrosion resistance; however, for the high Ce ion concentration, the barrier effect of the hybrid films was deteriorated. The results obtained by RBS showed that the concentration of Ce ion in the hybrid film increased linearly with the concentration of Ce ion in the sol. Moreover, it was verified that, for the nominal concentration of 0.05 M Ce ion in the sol, the Ce atomic fraction increased in the hybrid film, while the Si atomic fraction reduced, indicating the possible modification on the silane network due to the incorporation of Ce ions.
An embedded multi‐parameter corrosion sensor for reinforced concrete structures
Authors: Yu H. , Caseres L. 
Published: June 2011

AbstractA prototype of an embedded corrosion sensor has been developed for assessing the corrosion status of reinforcing steel bar (rebar) in concrete. The integrated sensor unit includes an Ag/AgCl probe, a metallic oxide probe, a multi‐electrode array sensor (MAS), and a four‐pin (Wenner) array stainless steel electrode for chloride content, pH, microcell corrosion current, and localized concrete resistivity measurements, respectively. A stable solid probe was used as the reference probe in this unit to express the potentiometric measurement of chloride content and pH probes. In this study, the chloride and pH probes were calibrated in simulated pore solutions (SPSs) regarding temperature and pH fluctuations. The corrosion current results of the MAS probe in SPSs matched very well with those obtained by the linear polarization resistance technique, which was conducted on companion carbon steel specimens. A sensor prototype was embedded into a paste cylinder for long‐term performance evaluation. Up‐to‐date results show that the sensor probes exhibit excellent sensitivity and reliability through 1 year of monitoring. Continuous monitoring in the laboratory for extended periods is underway.
Corrosion and self‐healing behaviour of AZ91D magnesium alloy in ethylene glycol/water solutions
Authors: Wang L. , Zhou T. , Liang J. 
Published: June 2011

AbstractCorrosion behaviour of magnesium alloy‐based engine parts in cooling system is an urgent fundamental issue in automotive field where magnesium alloys are increasingly used. In the present work, the corrosion behaviour of AZ91D magnesium alloys in various ethylene glycol/water solutions was studied by electrochemical measurements and immersion tests at room temperature. The surfaces of the samples after immersion tests were examined using scanning electron microscope (SEM) and X‐ray diffraction (XRD). The results showed that the corrosion rates of AZ91D magnesium alloys decreased with the increase of ethylene glycol concentration in ethylene glycol/water solutions and the corrosion process was dominated by pitting corrosion. A continuous protective film transferred from corrosion products was formed on the corroded surface after sufficient immersion duration in ethylene glycol/water solutions, which is able to heal the corrosion pits. The self‐healing behaviour inhibited the further corrosion of AZ91D magnesium alloy.
Numerical modelling of multiphase immiscible flow in double‐porosity featured groundwater systems
Authors: Ngien Su Kong , Rahman Norhan A. , Lewis Roland W. , Ahmad Kamarudin 
Published: June 2011

SUMMARYA numerical model describing the flow of multiphase, immiscible fluids in a deformable, double‐porosity featured soil has been developed. The model is focused on the modelling of the secondary porosity features in soil, which is more relevant to groundwater contamination problems. The non‐linear saturation and relative permeabilities were expressed as functions of the capillary pressures. The governing partial differential equations in terms of soil displacement and fluid pressures were solved numerically. Galerkin's weighted‐residual finite element method was employed to obtain the spatial discretization whereas temporal discretization was achieved using a fully implicit scheme. The model was verified against established, peer‐reviewed works, and the assumption that the immiscible fluids (non‐aqueous phase liquids) will flow preferentially through the secondary porosity features in soil was validated. Copyright © 2011 John Wiley & Sons, Ltd.