bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study on the Reactivity of Aldehydes in Electrolyzed Ionic Liquids: Benzoin Condensation – Volatile Organic Compounds (VOCs) vs. Room Temperature Ionic Liquids (RTILs)
Authors: Chiarotto I. , Feroci M. , Orsini M. , Feeney M. M. M. , Inesi A. 
Published: December 2010

AbstractThe benzoin condensation of aromatic and heteroaromatic aldehydes, catalyzed by electrochemically generated N‐heterocyclic carbenes, has been set up in the absence of organic solvents and bases. α‐Hydroxy ketones have been isolated in good to elevated yields, in short reaction times. Aldol products and carbene‐aldehyde adducts have been obtained in elevated yields from linear and short branched aldehydes, respectively. A comparison with the use of classical organic solvents has been reported
Retro‐Diels–Alder Reactions of Masked Cyclopentadienones Catalyzed by Heterogeneous Brønsted Acids
Authors: Demuynck Anneleen L. W. , Levecque Pieter , Kidane Aklilu , Gammon David W. , Sickle Eugene , Jacobs Pierre A. , De Vos Dirk E. , Sels Bert F. 
Published: December 2010

AbstractThe zeolite H‐Beta catalyzes the retro‐Diels–Alder reaction of a range of cyclopentadiene cyclo‐adducts at moderate temperatures and ambient pressure, in the presence of an active dienophile. The active catalyst was identified and optimum reaction conditions established after screening a range of zeolites in the retro‐Diels–Alder reaction of the cyclopentadiene adduct of cyclopentenone. Our results suggest that retro‐Diels–Alder reactions of tricyclodecadienones are catalyzed by Brønsted acids and the high catalytic performance of H‐Beta catalysts can be ascribed to the optimal balance between the number of acid sites and their strength as well as to the accessibility of these sites. The methodology was then applied to a series of alkyl derivatives of cyclopentadienylcyclopentenones to provide a viable alternative synthetic route to 4‐alkylcyclopentenones and the versatility of the approach was demonstrated by the successful cycloreversion of N‐cyclohexyl‐2‐azanorborn‐5‐ene.
Readily Accessible Oxazolidine Nitroxyl Radicals: Bifunctional Cocatalysts for Simplified Copper Based Aerobic Oxidation
Authors: Gartshore Christopher J. , Lupton David W. 
Published: December 2010

AbstractUsing a two‐step procedure a range of bifunctional oxazolidine nitroxyl radicals have been prepared. The application of these co‐catalysts to the copper‐based aerobic oxidation of alcohols was then investigated. From these studies it was found that the parent tetramethyloxazolidine nitroxyl radical L1 was competent for oxidation in the presence of 2,2′‐bipyridine, and the bifunctional pyridyl‐containing nitroxyl radicals L2 and L3 could be used in the absence of additional coordinating ligands. Following optimization, the scope of this simplified transformation was explored, demonstrating that a range of primary and secondary benzylic alcohols are readily oxidized. In addition, the oxidation of allylic alcohols and hydroquinone can be achieved.
Excess Phosphine Ligand Plays a Critical Role in the Asymmetric Copper(I) Iodide‐Catalyzed Conjugate Addition of Grignard Reagents to α,β‐Unsaturated Esters
Authors: Wang Shun‐Yi , Song Ping , Loh Teck‐Peng 
Published: December 2010

AbstractThe role of excess ligand in the asymmetric 1,4‐conjugate addition (ACA) of Grignard reagents to α,β‐unsaturated esters compounds catalyzed by copper(I) iodide‐2,2′‐bis(di‐p‐tolylphosphino)‐1,1′‐binaphthyl (CuI‐Tol‐BINAP) is explored herein. In addition, this methodology allows asymmetric induction to be carried out using a non‐chiral phosphine copper complex with excess of a chiral phosphine ligand.
The Critical Role of Processing and Morphology in Determining Degradation Rates in Polymer Solar Cells
Authors: Kumar Ankit , Hong Ziruo , Sista Srinivas , Yang Yang 
Published: December 2010

AbstractWith rapid increase in the efficiencies of polymer solar cells (PSCs) in the last few years, the issue of device stability is taking center stage in organic photovoltaic research. In this work, the effects of oxygen and light on the degradation of charge‐transport properties of the bulk polymer active layer are studied over short timescales. It is shown that although different processing techniques produce similar efficiencies for pristine devices, they result in different degradation rates. This variation in degradation rates is primarily due to slightly different morphology parameters, such as molecular packing or disorder in the film. Investigation reveals that the choice of processing for the devices should consider degradation rates as a critical parameter, not just the efficiencies of the pristine devices. It was found that degradation starts with broadening of the effective density of states due to photo‐oxidation. Both transient absorption and charge extraction by linearly increasing voltage (CELIV) measurements show increase in disorder in the films with progressive degradation. It is suggested that annealing provides the necessary thermal energy to reduce the trap states by flattening out the energy landscape of the pristine films, improving not only the efficiency, as reported previously, but also slowing the degradation rates.
Body composition trajectories into adolescence according to age at pubertal growth spurt
Authors: Buyken Anette E. , Bolzenius Katja , Karaolis‐Danckert Nadina , Günther Anke L.B. , Kroke Anja 
Published: December 2010

AbstractObjective: To investigate whether the development of body composition into adolescence differs among children with an early, average, or late pubertal growth spurt (age at take‐off [ATO]).Methods: Mixed‐effect polynomial models were applied to serial anthropometric measurements spanning from 4 years before to 4 years after ATO in 215 DONALD participants. Sex‐specific trajectories of fat mass index (FMI, FM/m2), fat‐free mass index (FFMI, FFM/m2), and their z‐scores were compared among those with an early, average, or late ATO.Results: Compared with girls with a late ATO (reference group), those with an early or average ATO experienced a significant increase in FFMI z‐scores [β (standard error) for linear trends in early and average ATO group: +0.15 (0.05) FFMI z‐scores/year (P = 0.001) and +0.11 (0.04) FFMI z‐scores/year (P = 0.005), respectively, adjusted for early life factors]. Similar differences were observed in boys [adjusted β (standard error): +0.20 (0.06) FFMI z‐scores/year (P = 0.0004) and +0.07 (0.05) FFMI z‐scores/year (P = 0.1), respectively]. Graphical illustration of the predicted trajectories revealed that differences in relative FFMI emerged from ATO onward. For FMI, comparison with late maturers showed a more pronounced quadratic trend (kg/m2/years2) (P = 0.01) among early‐maturing girls and a reduced linear trend in FMI z‐scores/year (P = 0.04) among early‐maturing boys.Conclusions: This longitudinal study suggests that children who experience an early pubertal growth spurt accrue progressively more fat‐free mass during the first years of puberty than late‐maturing peers of the same age. Higher levels of adiposity commonly observed in adults with early puberty onset are, thus, likely to develop subsequently in later adolescence. Am. J. Hum. Biol., 2010. © 2010 Wiley‐Liss, Inc.
Correlations for prediction of specific surface area and bulk and apparent densities of porous styrene‐divinylbenzene copolymers
Authors: Nodehi Azizollah , Hajiebrahimi Mohammad , Parvazinia Mahmoud , Shahrokhi Mohammad , Abedini Hossein 
Published: December 2010

AbstractMacroporous styrene‐divinylbenzene copolymers with different degree of crosslinking were prepared by suspension polymerization in presence of different binary mixtures of toluene and heptane, as diluent. Specific surface area, bulk and apparent densities, and pore volume of the resulting beads were determined experimentally. Applying the least square method to the experimental data, correlations for prediction of these properties were obtained. Effects of divinylbenzene concentration, diluent to comonomer volume ratio, and composition of the diluent mixture were considered in developing the aforementioned correlations. The influence of the reaction recipe on porous structure of the samples was also studied using scanning electron microscope (SEM). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis and Supramolecular Self‐Assembly of Coil‐Rod‐Coil Molecules: The Relationship between Self‐Assembled Nanostructures and Molecular Structures
Authors: Chen Yulan , Zhang Fan , Zhu Bo , Han Yang , Bo Zhishan 
Published: December 2010

AbstractHerein, the relationship between the supramolecularly self‐assembled nanostructures and the chemical structures of coil‐rod‐coil molecules is discussed. A series of nonamphiphilic coil‐rod‐coil molecules with different alkyl chains, central mesogenic groups, and chemical linkers were designed and synthesized. The solvent‐mediated supramolecular self‐assembling of these coil‐rod‐coil molecules resulted in rolled‐up nanotubes, nanofibers, submicron sized belts, needle‐like microcrystals, and amorphous structures. The self‐assembling behaviors of these coil‐rod‐coil molecules have been systematically investigated to reveal the relationship between the supramolecularly self‐assembled nanostructures and their chemical structures. With respect to the formation of rolled‐up nanotubes by self‐assembly of coil‐rod‐coil molecules, we have systematically investigated the following three influencing structural factors: 1) the alkyl chain length; 2) the central mesogenic group; (3) the linker type. These studies disclosed the key structural features of coil‐rod‐coil molecules for the formation of rolled‐up nanotubes.
Perylene‐Based Nanotweezers: Enrichment of Larger‐Diameter Single‐Walled Carbon Nanotubes
Authors: Backes Claudia , Schmidt Cordula D. , Hauke Frank , Hirsch Andreas 
Published: December 2010

AbstractThe solubilization of single‐walled carbon nanotubes (SWCNTs) by a novel tweezer‐shaped molecule with perylene bisimide moieties that act as aromatic anchoring groups is presented. Encouraging results of the tweezer‐dispersion concept is combined with the outstanding exfoliation and dispersion efficiencies of designed perylene bisimide derivatives, which have previously turned out as most‐powerful SWCNT dispersants. Based on the preferred interaction between the nanotweezer and SWCNTs with diameters larger than 0.8 nm, the supernatant was depleted after mild centrifugation in SWCNT species of smaller diameters. Characterization was carried out by a combination of UV/Vis and nIR absorption spectroscopy as well as emission spectroscopy of the SWCNTs and perylene. This study presents the foundation for a further improvement of selective SWCNT dispersion and sorting by designed molecules.
Ion flux and the function of endosomes and lysosomes: pH is just the start
Authors: Scott Cameron C. , Gruenberg Jean 
Published: December 2010

AbstractThe ionic nature of endosomes varies considerably in character along the endocytic pathway. Counter‐ion flux across the limiting membrane of endosomes has long been considered essential for full acidification and normal endosome/lysosomal function. The proximal functions of luminal ions, however, have been difficult to assess. The recent development of transgenic mice carrying mutations in the intracellular chloride channels (ClCs) has provided a tool to uncouple Cl− influx from endosomal acidification. Intriguingly, many of the defects of the endo‐lysomal system attributed to aberrant pH persist in the Cl−‐deficient mice implying a direct regulatory role for Cl− influx in endosome function. These observations may begin to explain the abundance of endosomal ion transporters, including ClCs, sodium‐proton exchangers, two‐pore channels and mucolipins, that have been localized to endo‐lysosomes, and the extensive changes in luminal ion composition therein. In this review, we summarize what is known regarding the mediators of endosomal ion flux, and discuss the implications of changing ionic content on endo‐lysosomal function.
Religion and the decision to donate organs: Exploring the potential role of religious leaders
Authors: Vincent Donald E. , Anker Ashley E. , Feeley Thomas H. 
Published: December 2010

AbstractThe two‐step flow model of communication (Katz, 1957) suggests opinion leaders obtain critical information from the mass media and, in turn, communicate this information to interpersonal contacts such as friends, family and co‐workers. It is suggested that religious leaders (RLs) may serve as opinion leaders on the topic of organ donation by debunking donation myths, promoting donation during worship services, or communicating the benefit of donation to families faced with the opportunity to participate in living or cadaveric donation. The current study examined the personal knowledge, experiences, and willingness to communicate about organ donation in a sample of RLs (N = 59) in Rochester, New York. Structured interviews were conducted in summer and fall of 2009 with a random sample of RLs. Results indicate a disparity between RLs' expressed personal support for donation and their engagement in donor registration. Approximately one‐quarter of RLs have spoken about donation during a religious service and many indicate their knowledge is not sufficient to discuss organ donation in detail. Results elaborate on how RLs may be trained to serve as opinion leaders in the promotion of organ donation. Copyright © 2010 John Wiley & Sons, Ltd.
A Pyrophosphate‐Responsive Gadolinium(III) MRI Contrast Agent
Authors: Surman Andrew J. , Bonnet Célia S. , Lowe Mark P. , Kenny Gavin D. , Bell Jimmy D. , Tóth Éva , Vilar Ramon 
Published: December 2010

AbstractThis study shows that the relaxivity and optical properties of functionalised lanthanide‐DTPA‐bis‐amide complexes (lanthanide=Gd3+ and Eu3+, DTPA=diethylene triamine pentaacetic acid) can be successfully modulated by addition of specific anions, without direct Ln3+/anion coordination. Zinc(II)‐dipicolylamine moieties, which are known to bind strongly to phosphates, were introduced in the amide “arms” of these ligands, and the interaction of the resulting Gd–Zn2 complexes with a range of anions was screened by using indicator displacement assays (IDAs). Considerable selectivity for polyphosphorylated species (such as pyrophosphate and adenosine‐5′‐triphosphate (ATP)) over a range of other anions (including monophosphorylated anions) was apparent. In addition, we show that pyrophosphate modulates the relaxivity of the gadolinium(III) complex, this modulation being sufficiently large to be observed in imaging experiments. To establish the binding mode of the pyrophosphate and gain insight into the origin of the relaxometric modulation, a series of studies including UV/Vis and emission spectroscopy, luminescence lifetime measurements in H2O and D2O, 17O and 31P NMR spectroscopy and nuclear magnetic resonance dispersion (NMRD) studies were carried out.
Concurrent Symmetries: The Interplay Between Local and Global Molecular Symmetries
Authors: Echeverría Jorge , Carreras Abel , Casanova David , Alemany Pere , Alvarez Santiago 
Published: December 2010

AbstractWe analyze in this article the degree to which different groups of atoms retain local symmetries when assembled in a molecule. This study is carried out by applying continuous symmetry measures to several families of mixed sandwiches, a variety of piano‐stool molecules, and several organic groups. An analysis of the local symmetry of the electron density shows that, sandwiched between two regions of different symmetry that correspond to the ligand sets, its symmetry is cylindrical at the central metal atom.
CFD modelling of dust explosions: Rapid combustion in a 20 L apparatus
Authors: Bind Vimlesh Kumar , Roy Shantanu , Rajagopal Chitra 
Published: December 2010

AbstractDust explosions are combustion of fine dust particles in a rapid reaction regime. They are of relatively common occurrence in industries which have unit operations like grinding, pneumatic conveying, drying, and fine particle collection: generally those units which handle fine particles or “dust” in an oxygen‐rich environment. At present, mitigation and prevention of dust explosion accidents is largely based on operator experience and safety inspection heuristics: knowledge that often cannot be documented or put into scientifically developed safety rules. Part reason for this state of affairs is our lack of fundamental understanding on how a dust explosion progresses after ignition of the dust cloud. In this contribution, with a view towards improving our understanding of dust explosions, we propose a multi‐scale modelling approach for modelling dust explosion phenomena in a standard 20 L Siwek Apparatus. The modelling approach is based on computational fluid dynamics methods treating Aluminum dust cloud as a quasi‐homogeneous phase.
Advances and opportunities at the interface between microbial bioenergy and nanotechnology
Authors: Pugh Shawn , McKenna Rebekah , Moolick Richard , Nielsen David R. 
Published: December 2010

AbstractIn this review, we highlight many recent developments in nanotechnology of critical relevance to microbial bioenergy synthesis. Nanoparticles, nanotubes, nanofibres, and nanoporous materials, are each being utilised in powerful ways as tools for feedstock processing, genetic engineering, and biofuel harvesting, as well as in bioelectrochemical systems. As materials and techniques continue to mature, nanomaterials will become a truly integral part of the bioenergy sector. Sustainable bioenergy production will ultimately be achieved through interdisciplinary efforts that continue to bridge the gap between these traditionally distinct fields of study.
Palmitoylated SDF1 α Shows Increased Resistance against Proteolytic Degradation in Liver Homogenates
Authors: Bellmann‐Sickert Kathrin , Beck‐Sickinger Annette G. 
Published: December 2010

AbstractThe chemokine stromal cell‐derived factor‐1 α (SDF1 α) is strongly involved in organogenesis, as well as inflammation and tissue repair, and acts by attracting different kinds of stem and progenitor cells. Therefore, it constitutes an interesting compound for drug development in regenerative medicine. However, it is prone to inactivation by proteolytic cleavage in human serum. Accordingly, it has to be stabilized against enzymatic degradation for any therapeutic application. We synthesized a palmitoylated SDF1 α analogue by native chemical ligation. Both the N‐terminal thioester and the C‐terminal palmitoylated fragment were prepared by solid‐phase peptide synthesis. The activity of the refolded and pure compound was determined by an inositol phosphate turnover assay and revealed no loss in receptor activation. Additionally, resistance to proteolytic degradation was investigated in porcine liver homogenates and showed a near sevenfold increased half time. This study is a proof of principle approach for the lipidation of SDF1 α and provides a basis for further engineering of the chemokine in order to increase its therapeutic value.
The theory of DQF‐COSY NMR experiments. I. Amplitude modulation of the signal
Authors: Kempgens P. 
Published: December 2010

AbstractThe two‐dimensional (2D) NMR double‐quantum filtered COSY spectrum of an AX spin system of spin‐1 has been calculated by numerical density matrix calculations. The basic phase cycle to achieve double quantum filtration consists of four steps. The total signal after these four steps is modulated in amplitude as a function of t1. It is therefore not possible to determine the sign of the modulation frequencies Ωu,t in a 2D complex Fourier transformation. Additional steps in the phase cycle are needed to achieve phase modulation. © 2010 Wiley Periodicals, Inc. Concepts Magn Reson Part A 36A: 341–346, 2010.
Head gradient coil for MRI with a window
Authors: Sánchez Clemente Cobos 
Published: December 2010

AbstractBoundary element methods have been successfully used to design gradient coils for MRI. Here the full potential of this geometry‐independent technique is used to design head gradient coils, incorporating a rectangular window so as to allow visual interaction with the subject. The inclusion of the window can ameliorate significantly the claustrophobia perception in many subjects, as well as, it allows visual stimuli necessary for certain fMRI experiments to be displayed. This work details some numerical examples for the design of torque‐balanced coils of minimum inductance, where the incorporation of the window is shown to improve visual interaction with the subject compared with conventional coils. © 2010 Wiley Periodicals, Inc. Concepts Magn Reson Part A 36A: 388–393, 2010
Neuronal polarity in Drosophila: Sorting out axons and dendrites
Authors: Rolls Melissa M. 
Published: December 2010

AbstractDrosophila neurons have identifiable axons and dendrites based on cell shape, but it is only just starting to become clear how Drosophila neurons are polarized at the molecular level. Dendrite‐specific components including the Golgi complex, GABA receptors, neurotransmitter receptor scaffolding proteins, and cell adhesion molecules have been described. Proteins involved in constructing presynaptic specializations are concentrated in axons of some neurons. A very simple model for how these components are distributed to axons and dendrites can be constructed based on the opposite polarity of microtubules in axons and dendrites: dynein carries cargo into dendrites, and kinesins carry cargo into axons. The simple model works well for multipolar neurons, but will likely need refinement for unipolar neurons, which are common in Drosophila. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 71: 419–429, 2011
Maintenance of neuronal polarity
Authors: Szu‐Yu Ho Tammy , Rasband Matthew N. 
Published: December 2010

AbstractNeurons are highly polarized cells with distinct domains responsible for receiving, transmitting, and propagating electrical signals. Central to these functions is the axon initial segment (AIS), a short region of the axon adjacent to the cell body that is enriched in voltage‐gated ion channels, cell adhesion molecules, and cytoskeletal scaffolding proteins. Traditionally, the function of the AIS has been limited to its role in action potential initiation and modulation. However, recent experiments indicate that it also plays essential roles in neuronal polarity. Here, we review how initial segments are assembled, and discuss proposed mechanisms for how the AIS contributes to maintenance of neuronal polarity. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 71: 474–482, 2011
The role of Rho GTPase proteins in CNS neuronal migration
Authors: Govek Eve‐Ellen , Hatten Mary E. , Van Aelst Linda 
Published: December 2010

AbstractThe architectonics of the mammalian brain arise from a remarkable range of directed cell migrations, which orchestrate the emergence of cortical neuronal layers and pattern brain circuitry. At different stages of cortical histogenesis, specific modes of cell motility are essential to the stepwise formation of cortical architecture. These movements range from interkinetic nuclear movements in the ventricular zone, to migrations of early‐born, postmitotic polymorphic cells into the preplate, to the radial migration of precursors of cortical output neurons across the thickening cortical wall, and the vast, tangential migrations of interneurons from the basal forebrain into the emerging cortical layers. In all cases, actomyosin motors act in concert with cell adhesion receptor systems to provide the force and traction needed for forward movement. As key regulators of actin and microtubule cytoskeletons, cell polarity, and adhesion, the Rho GTPases play critical roles in CNS neuronal migration. This review will focus on the different types of migration in the developing neocortex and cerebellar cortex, and the role of the Rho GTPases, their regulators and effectors in these CNS migrations, with particular emphasis on their involvement in radial migration. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 71: 528–553, 2011