bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanistic Study of the Palladium–Phenanthroline Catalyzed Carbonylation of Nitroarenes and Amines: Palladium–Carbonyl Intermediates and Bifunctional Effects
Authors: Ragaini Fabio , Gasperini Michela , Cenini Sergio , Arnera Lucia , Caselli Alessandro , Macchi Piero , Casati Nicola 
Published: March 2009

AbstractPalladium–phenanthroline complexes catalyze both the nitroarene carbonylation reaction and the amine oxidative carbonylation reaction to give, depending on the conditions, carbamates and ureas. There is evidence that the key step in both processes is the amine carbonylation. Here, we show that when the reaction is run in methanol key intermediate compounds have the general formula [Pd(RPhen)(COOMe)2] (1) (RPhen=1,10‐phenanthroline or one of its substituted derivatives). The kinetics of the reaction of 1 with toluidine in the presence of a carboxylic or phosphorus acid is first‐order with respect to complex, acid, and toluidine. A CO atmosphere is also required for the reaction to proceed. Acid dimerization was shown not to be influential under the concentration conditions examined, but reaction between the acid and toluidine is not negligible and a correction has to be applied. Diphenylphosphinic acid is more effective than any carboxylic acid in promoting this reaction, as also observed under catalytic conditions. A series of equilibria and an irreversible acid‐assisted proton transfer explain the observed data. Formation of an adduct between complexes of the kind 1 and CO was spectroscopically observed when RPhen=2,9‐Me2Phen. Several analogous complexes were also spectroscopically characterized and the X‐ray structure of [Pd(2,9‐Me2Phen)Cl2(CO)] was solved. This shows an asymmetric coordination of the nitrogen ligand. Kinetic measurements were also conducted under catalytic conditions. An Eyring plot shows that the effect of the acidic promoter is to decrease the ΔS ≠ value, whereas no positive effect is observed on ΔH ≠. A temperature‐dependent correction for the reaction between the acid and aniline and phenanthroline present under the reaction conditions has to be applied. Comparison of the results obtained under stoichiometric and catalytic conditions strongly supports the view that 1 is involved even in the latter and that the acid is acting as a bifunctional promoter.
Study of the MR relaxation of microglia cells labeled with Gd‐DTPA‐bearing nanoparticles
Authors: Ribot Emeline Julie , Miraux Sylvain , Delville Marie‐Hélène , Bouchaud Véronique , Lacomme Sabrina , Gontier Etienne , Bouzier‐Sore Anne‐Karine , Franconi Jean‐Michel , Thiaudiere Eric , Voisin Pierre 
Published: March 2009

AbstractTherapies involving cells as vehicles need to visualize in situ the trafficking of the cells concerned. This cellular imaging can be driven by cell contrast agent‐based nanoparticle internalization and non‐invasive MRI (magnetic resonance imaging) detection. Here, microglial cells, that would transport a suicide gene to a glioma, were incubated for different times, with various concentrations of silica nanoparticles on which numerous Gd‐DTPA were grafted. The goal of this study was to investigate the repartition of cell‐associated particles. MRI was used to quantitatively follow the particle uptake process. Fluorescence microscopy images showed that, although most of the nanoparticles were internalized, some remained adsorbed on the extracellular membrane surface. The cells were then submitted to various treatments: glycine to release bound nanoparticles and/or ultrasound to destroy the cell membranes. The R1 relaxation rates were measured at 4.7 T. R1 was maximal for 4 h of incubation, decreased after 8 h and remained stable for the 24 following hours. The magnetic resonance signal of ultrasonicated and glycine‐treated cells made it possible to quantify the loss of bound nanoparticles after 8 h. Nevertheless, this release did not prevent cell detection since the internalized nanoparticles are enough concentrated to visualize the labeled cells even after 4 days of cell growth. These results highlight the compartmentalization of nanoparticles in microglia and the evolution of the MR signal of the labeled cells. This study could be of importance to interpret in vivo the MR signal changes that could occur after administration of such nanoparticle‐labeled cells in therapeutic strategies. Copyright © 2009 John Wiley & Sons, Ltd.
MR determination of glomerular filtration rate in subjects with solitary kidneys in comparison to clinical standards of renal function: feasibility and preliminary report
Authors: Katzberg Richard W. , Buonocore Michael H. , Low Roger , Hu Brian , Jain Kiran , Castillo Michele , Troxel Scott , Nguyen Mike M. 
Published: March 2009

AbstractThis study was conducted to demonstrate the feasibility of quantifying single kidney glomerular filtration rate (skGFR) by magnetic resonance (MR) by comparison to the clinical estimates of GFR in volunteer subjects with a single kidney. Seven IRB‐approved subjects with a solitary kidney, stable serum creatinine (SCr) and a 24 h creatinine clearance (CrCl) volunteered to undergo an MR examination that determined renal extraction fraction (EF) with a breathhold inversion recovery echo planar pulse sequence and renal blood flow with a velocity encoded phase imaging sequence. The product of EF and blood flow determines GFR. These values were compared with the 24 h CrCl, estimated GFR by the modification of diet in renal disease (MDRD) regression analysis and the Cockroft–Gault (CG) determination of CrCl. The mean and standard deviation of differences between the MR GFR, MDRD and CG vs the 24 h CrCl were 12.3 ± 35.7, −8.9 ± 18.5 and 1.2 ± 19.6, respectively. The Student t‐test showed that none of the mean differences were statistically significant between techniques. This clinical investigation shows that MR can be used for skGFR determination in human subjects with comparable values to those derived from clinically used serum‐based GFR estimation techniques. Copyright © 2009 John Wiley & Sons, Ltd.
Inputs to serotonergic neurons revealed by conditional viral transneuronal tracing
Authors: Braz João M. , Enquist Lynn W. , Basbaum Allan I. 
Published: March 2009

AbstractDescending projections arising from brainstem serotonergic (5HT) neurons contribute to both facilitatory and inhibitory controls of spinal cord “pain” transmission neurons. Unclear, however, are the brainstem networks that influence the output of these 5HT neurons. To address this question, here we used a novel neuroanatomical tracing method in a transgenic line of mice in which Cre recombinase is selectively expressed in 5HT neurons (ePet‐Cre mice). Specifically, we injected the conditional pseudorabies virus recombinant (BA2001) that can replicate only in Cre‐expressing neurons. Because BA2001 transports exclusively in a retrograde manner, we were able to reveal a subset of the neurons and circuits that are located upstream of the Cre‐expressing 5HT neurons. We show that diverse brainstem regions differentially target the 5HT neurons of the dorsal raphe (DR) and the nucleus raphe magnus of the rostroventral medulla (RVM). Among these are several catecholaminergic and cholinergic cell groups, the periaqueductal gray, several brainstem reticular nuclei, and the nucleus of the solitary tract. We conclude that a brainstem 5HT network integrates somatic and visceral inputs arising from various areas of the body. We also identified a circuit that arises from projection neurons of deep spinal cord laminae V–VIII and targets the 5HT neurons of the NRM, but not of the DR. This spinoreticular pathway constitutes an anatomical substrate through which a noxious stimulus can activate 5HT neurons of the NRM and in turn could trigger descending serotonergic antinociceptive controls. J. Comp. Neurol. 514:145–160, 2009. © 2009 Wiley‐Liss, Inc.
Using clouds to provide grids with higher levels of abstraction and explicit support for usage modes
Authors: Jha Shantenu , Merzky Andre , Fox Geoffrey 
Published: March 2009

AbstractGrids in their current form of deployment and implementation have not been as successful as hoped in engendering distributed applications. Among other reasons, the level of detail that needs to be controlled for the successful development and deployment of applications remains too high. We argue that there is a need for higher levels of abstractions for current Grids. By introducing the relevant terminology, we try to understand Grids and Clouds as systems; we find this leads to a natural role for the concept of Affinity, and argue that this is a missing element in current Grids. Providing these affinities and higher‐level abstractions is consistent with the common concepts of Clouds. Thus this paper establishes how Clouds can be viewed as a logical and next higher‐level abstraction from Grids. Copyright © 2009 John Wiley & Sons, Ltd.
Growth Mechanism and Chemical Structure of Amorphous Hydrogenated Silicon Carbide (a‐SiC:H) Films Formed by Remote Hydrogen Microwave Plasma CVD From a Triethylsilane Precursor: Part 1
Authors: Wrobel Aleksander M. , Walkiewicz‐Pietrzykowska Agnieszka , Ahola Marja , Vayrynen I. Juhani , Ferrer‐Fernandez Francisco J. , Gonzalez‐Elipe Agustin R. 
Published: March 2009

AbstractAmorphous hydrogenated silicon carbide (a‐SiC:H) films are produced by remote microwave hydrogen plasma (RHP)CVD using triethylsilane (TrES) as the single‐source precursor. The reactivity of particular bonds of the precursor in the activation step is examined using tetraethylsilane as a model compound for the RHP‐CVD experiments. The susceptibility of a TrES precursor towards film formation is characterized by determining the yield of RHP‐CVD and comparing it with that of the trimethylsilane precursor. The effect of substrate temperature (Ts) on the rate of the RHP‐CVD process, chemical composition, and chemical structure of the resulting a‐SiC:H films is reported. The substrate temperature dependence of the film growth rate implies that film growth is independent of the temperature and RHP‐CVD is a mass transport‐limited process. The examination of the a‐SiC:H films, performed by means of X‐ray photoelectron spectroscopy (XPS), elastic recoil detection analysis (ERDA), and Fourier transform infrared absorption spectroscopy (FTIR), reveals that the increase in the substrate temperature from 30 °C to 400 °C causes the elimination of organic moieties from the film and the formation of a Si‐carbidic network structure. On the basis of the results of the structural study, the chemistry involved in film formation is proposed.
Adolescent female rats are more resistant than males to the effects of early stress on prefrontal cortex and impulsive behavior
Authors: Spivey Jaclyn M. , Shumake Jason , Colorado Rene A. , Conejo‐Jimenez Nelida , Gonzalez‐Pardo Hector , Gonzalez‐Lima F. 
Published: March 2009

AbstractWe tested the hypothesis that adolescent Sprague–Dawley females may be more resistant than males to display impulsive behavior and lower prefrontal cortex thickness after mother‐infant separation (MS). Starting at postnatal day 2 (P2), the MS group was separated 6 hr/day and the early handled (EH) group 15 min/day for 10 days, and another group was standard facility reared (SFR). Subjects were examined for novel open‐field activity (P28), light–dark apparatus (P29), familiar open‐field (P30) and frontal cortical thickness. This protocol resulted in impulsive behavior in MS rats relative to EH and SFR, but this effect was less pronounced in females than males. MS affected the two sexes differently in terms of decreased prefrontal cortex dorsoventral thickness, with this effect being significant in males but not females. Neuroanatomical and behavioral documentation that adolescent females are more resistant than males to ADHD‐like effects of maternal separation have not been previously reported. © 2009 Wiley Periodicals, Inc. Dev Psychobiol 51: 277–288, 2009
Emotion and eating psychopathology: Links with attitudes toward emotional expression among young women
Authors: Meyer Caroline , Leung Newman , Barry Letitia , De Feo Danielle 
Published: March 2009

AbstractObjectiveThe aim of this study was to determine links between attitudes toward emotional expression and levels of eating psychopathology among young women.MethodEighty‐nine young female volunteers completed the Attitudes Toward Emotional Expression scale (AEE) and the Eating Disorders Examination Questionnaire (EDEQ).ResultsThere were positive significant associations between AEE subscales and EDEQ scores. In particular, those women who scored high on the EDEQ eating, shape, and weight subscales believe that to display emotion is a sign of weakness. Although those participants with high EDEQ weight concern scores were also likely to believe that they should keep their emotions under control and that others might be rejecting or damaged should they themselves display their emotions.DiscussionThese findings require replication with a clinical sample, however, they suggest that challenging these attitudes is potentially a useful step in facilitating acceptance of emotion and the development of adaptive emotion regulation strategies in those women with high levels of eating psychopathology. © 2009 by Wiley Periodicals, Inc. Int J Eat Disord 2010
Nickel Complexes of N/O‐Functionalized N‐Heterocyclic Carbenes as Precatalysts for Michael Reactions in Air at Room Temperature Under the Much Preferred Base‐Free Conditions
Authors: Ray Sriparna , Shaikh Mobin M. , Ghosh Prasenjit 
Published: March 2009

AbstractA series of several new nickel precatalysts supported overN/O‐functionalized N‐heterocyclic carbenes (NHC) for the Michael reactions of β‐dicarbonyl, β‐keto ester, β‐diester, and α‐cyano ester compounds with α,β‐unsaturated carbonyl compounds in air at ambient temperature under the much preferred base‐free conditions are reported. Specifically, the nickel complexes, [1‐(R1‐aminocarbonylmethyl)‐3‐R2‐imidazol‐2‐ylidene]2Ni [R1 = 2‐C6H4(OMe); R2 = Me (1b), iPr (2b), CH2Ph (3b) and R1 = 2‐CH2C4H3O; R2 = Me (4b), CH2Ph (5b)] carried out the highly convenient base‐free Michael addition of the activated C–H compounds across α,β‐unsaturated carbonyl compounds in air at room temperature. The complexes 1b–5b were synthesized by the direct reaction of the respective imidazolium chloride salt with NiCl2·6H2O in CH3CN in the presence of K2CO3 as a base. The exceptional stability of 1b–5b has been attributed to the deeply buried nickel–NHC σ‐bonding molecular orbitals as evidenced from the density functional theory (DFT) studies. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Catalyst Leaching as an Efficient Tool for Constructing New Catalytic Reactions: Application to the Synthesis of Cyclic Vinyl Sulfides and Vinyl Selenides (Eur. J. Inorg. Chem. 9/2009)
Authors: Ananikov Valentine P. , Gayduk Konstantin A. , Beletskaya Irina P. , Khrustalev Victor N. , Antipin Mikhail Yu. 
Published: March 2009

AbstractThe cover picture shows the impact of the phosphane ligand on solid metal nanoparticles, which initiates transformation of the metal species into a high‐performance catalyst. The evolution of the transition‐metal complexes was monitored by NMR spectroscopy, and the active form of the catalyst was detected in the 2D HMQC spectrum. A novel synthetic procedure to access cyclic vinyl chalcogenides was developed by utilizing an in situ designed catalyst in an E–E bond addition reaction to acetylenes (E = S, Se). Details are discussed in the article by V. P. Ananikov, I. P. Beletskaya et al. on p. 1149 ff.
Towards a New SPE Material for EDCs: Fully Automated Synthesis of a Library of Tripodal Receptors Followed by Fast Screening by Affinity LC
Authors: Van der Plas Steven E. , Van Hoeck Els , Lynen Fréderic , Sandra Pat , Madder Annemieke 
Published: March 2009

AbstractA series of human estrogen receptor (hER) mimics were synthesised. On the basis of the knowledge on the structure of the hormone binding domain of the hER, three different peptide chains were constructed onto a tripodal scaffold. By using a fully automated solid‐phase synthesis protocol, 120 members with known identity were synthesised in only a week. Affinity towards estrogenic compounds was checked by affinity LC. For this purpose, ethinylestradiol was “clicked” onto a modified‐silica phase, and the obtained material was packed into an HPLC column. The results stemming from the affinity LC experiments were confirmed by clicking one library member to silica and by using this solid phase to extract different endocrine‐disrupting chemicals (EDCs) from aqueous media. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Redox‐ and pH‐Controlled Mechanized Nanoparticles
Authors: Khashab Niveen M. , Trabolsi Ali , Lau Yuen A. , Ambrogio Michael W. , Friedman Douglas C. , Khatib Hussam A. , Zink Jeffrey I. , Stoddart J. Fraser 
Published: March 2009

AbstractA new class of mechanized silica nanoparticles, which exploits the stability of the inclusion complexes formed between ferrocenedicarboxylic acid and both cucurbit[7]uril (CB7) and β‐cyclodextrin (β‐CD), are described. Mesoporous silica nanoparticles, capable of storing a payload of small molecules and releasing it following particular activation processes, have been designed and decorated with ferrocenecarboxylic acid stalks. The storage and release of the payload is controlled by the host–guest interaction between the ferrocene moiety (guest) and the ring moiety (CB7 or β‐CD). Ferrocene‐based Mechanized NanoParticles (FMNPs) were efficiently prepared, loaded with Rhodamine dye, and then tested under different activation procedures. The systems operated successfully under redox control (oxidation of ferrocenedicarboxylic acid) in the presence of β‐CD and under pH control (deprotonation of ferrocenedicarboxylic acid pH > 4) in the presence of CB7.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Synthesis of Enantiopure α‐Chlorocyclobutanones and Cyclobutanols as Scaffolds for the Diverted Synthesis of Serine Protease Inhibitors
Authors: Yang Gaoqiang , Ghosez Léon 
Published: March 2009

AbstractSynthetic paths towards highly functionalized α‐chlorocyclobutanone scaffolds susceptible to lead to serine proteases inhibitors were explored. The syntheses started from bicyclic α‐chlorocyclobutanones 3, which are readily available from Seebach's oxazolines. It was found that the carbonyl group of the bicyclic α‐chlorocyclobutanones was highly electrophilic and readily reacted with a hydroxy group to give, for example, cyclized compound 4. Also, the presence of this reactive carbonyl group did not allow the regeneration of the protected amine and hydroxy groups. Thus, the functional manipulation of these bicyclic α‐chlorocyclobutanones required prior reduction of the carbonyl group to the corresponding cyclobutanol. Accordingly, enantiopure cyclobutanone 3d was stereoselectively reduced to exo‐cyclobutanol 15. Allylation of the alcohol followed by TEMPO‐catalyzed oxidation of the primary alcohol of the side chain and benzylation of the resulting carboxylic acid yielded compound 19. Cleavage of the oxazolidine ring occurred smoothly to yield densely functionalized cyclobutanol scaffold 20. A similar route allowed the efficient preparation of cyclobutanol scaffolds 14 and 25a–d in 25–27 % yields. TEMPO‐catalyzed oxidation of the cyclobutanol gave an excellent yield of corresponding cyclobutanones 26a,b(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Mnemic neglect is not an artifact of expectancy: The moderating role of defensive pessimism
Authors: Newman Leonard S. , Nibert Jeffrey A. , Winer E. Samuel 
Published: March 2009

AbstractResearch supporting the mnemic neglect model finds that people more easily recall positive than negative personality feedback, even when only asked to imagine that the feedback is real. The same bias is not found when people are asked to recall information about other people. Despite evidence that these findings reflect self‐enhancement motives, more research is needed to rule out the possibility that they instead simply reflect expectancies. Results supported the mnemic neglect model, and revealed that expectancies predicted recall only for a subgroup of participants who did not demonstrate the self–other recall bias characteristic of mnemic neglect: defensive pessimists, who are more likely than other people to process social information by comparing it to their expectancies. These findings suggest that mnemic neglect is not an artifact of expectancies, and is not driven by other self‐evaluation motives (such as self‐verification or self‐assessment). Copyright © 2009 John Wiley & Sons, Ltd.
The BRCA1‐dependent ubiquitin ligase, γ‐tubulin, and centrosomes
Authors: Parvin Jeffrey D. 
Published: March 2009

AbstractMutation of the breast and ovarian cancer specific tumor suppressor, BRCA1, results in supernumerary and hyperactive centrosomes, which in turn likely contribute to the aneuploidy evident in breast cancer cells. The BRCA1‐dependent ubiquitin ligase activity is required for the regulation of centrosome function, and among its substrates is γ‐tubulin. Data suggest that during S and G2 phases of the cell cycle, the normal function of BRCA1 directs the ubiquitination of γ‐tubulin, resulting in inhibition of centrosome microtubule nucleation function and blocking of centrosome reduplication. Loss of BRCA1 activity, as occurs in breast cancer cells, would result in centrosomes that are unrestrained, leading to the hyperactive and over‐duplicated centrosomes often observed in breast cancer cells. The current knowledge of BRCA1 regulation of centrosomes will be discussed in this focused review, and it will be suggested that this function is important for the tumor suppression phenotype of BRCA1. Environ. Mol. Mutagen. 2009. © 2009 Wiley‐Liss, Inc.
Centriole separation in DNA damage‐induced centrosome amplification
Authors: Saladino Chiara , Bourke Emer , Conroy Pauline C. , Morrison Ciaran G. 
Published: March 2009

AbstractAltered centrosome numbers are seen in tumor cells in response to DNA damaging treatments and are hypothesised to contribute to cancer development. The mechanism by which the centrosome and chromosome cycles become disconnected after DNA damage is not yet clear. Here, we show that centrosome amplification occurs after ionising radiation (IR) in chicken DT40 cells that lack DNA‐PK, Ku70, H2AX, Xpa, and Scc1, demonstrating that these activities are not required for centrosome amplification. We show that inhibition of topoisomerase II induces Chk1‐dependent centrosome amplification, a similar response to that seen after IR. In the immortalised, nontransformed hTERT‐RPE1 line, we observed centriole splitting, followed by dose‐dependent centrosome amplification, after IR. We found that IR results in the formation of single, not multiple, daughter centrioles during centrosome amplification in U2OS osteosarcoma cells. Analysis of BRCA1 and BRCA2 mutant tumor cells showed high levels of centriole splitting in the absence of any treatment. IR caused pronounced levels of centrosome amplification in BRCA1 mutant breast cancer cells. These data show that centrosome amplification occurs after different forms of DNA damage in chicken cells, in nontransformed human cells and in human tumor cell lines, indicating that this is a general response to DNA damaging treatments. Together, our data suggest that centriole splitting is a key step in potentiation of the centrosome amplification that is a general response to DNA damage. Environ. Mol. Mutagen. 2009. © 2009 Wiley‐Liss, Inc.