bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cages on Surfaces: Thiol Functionalisation of CoIII Sarcophagine Complexes
Authors: Harrowfield Jack M. , Koutsantonis George A. , Kraatz Heinz‐Bernhard , Nealon Gareth L. , Orlowski Grzegorz A. , Skelton Brian W. , White Allan H. 
Published: November 2006

AbstractA number of new (sarcophagine)cobalt compounds containing oligopeptide substituents terminated by a mercaptoethylamide unit, [Co(R)(R′)sar]26+ (R = NH2, CH3; R′ = NHpeptideCONHCH2CH2S–), have been prepared utilising the carboxymethyl complexes [Co(R){N(CH2CO2H)}sar]3+ (R = NH2, CH3), and subsequently characterised. The amino acid residues, terminating with cystamine groups, were introduced into the carboxymethyl complexes using standard peptide coupling chemistry. The solid‐state structures of [Co(CH3){N(CH2CO2H)}sar]Cl4·H2O, [Co(CH3){N(CH2CO2H)2}sar]Cl3·2H2O and [Co(CH3){N(CH2CO2)2}sar]Cl·6.5H2O were determined by single‐crystal X‐ray diffraction experiments, the first two forming lattices containing homochiral sheets of cations in planes parallel to [0,0,1]. In the structure of [Co(CH3){N(CH2CO2H)}sar]Cl4·H2O, the cations are of the same absolute configuration, but this alternates from one sheet tothe next. In the dihydrate, [Co(CH3){N(CH2CO2H)2}sar]Cl3·2H2O, the structure appears to be very similar. The sheet alternation is different from the structure of the monohydrate, [Co(CH3){N(CH2CO2H)}sar]Cl4·H2O. The deprotonated imidodiacetate complex, [Co(CH3){N(CH2CO2)2}sar]Cl·6.5H2O, was prepared in an unrelated reaction; the structure displays hydogen‐bonding interactions involving the carboxylate groups and coordinated NH units. The solution electrochemistry of these compounds has been investigated using both cyclic voltammetry and differential pulse voltammetry. The compounds exhibited pH‐dependent, quasi‐reversible redox behaviour. A monolayer was prepared by the interaction of [Co(R)sar(GlyNHCH2CH2S–)]26+ and a gold microelectrode using both conventional “self assembly” (SAM) and electrodeposition (EDM) techniques. Surface cyclic voltammograms were measured, which, after a period of induction associated with surface reorganisation, were typical of an ordered monolayer. The monolayer was characterised by XPS, showing peaks assigned to the presence of S, Co, N, O and C. Ellipsometry gave a film thickness of 7 ± 1 Å, consistent with the formation of a mono‐ rather than a multi‐layer. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Alkylmono(cyclopentadienyl)titanium Complexes Containing the 2,2′‐Methylenebis(6‐tert‐butyl‐4‐methylphenoxido) Ligand – Studies on the Nature of the Catalytic Species Present in α‐Olefin Polymerisation Processes
Authors: González‐Maupoey Marta , Cuenca Tomás , Frutos Luis Manuel , Castaño Obis , Herdtweck Eberhardt , Rieger Bernhard 
Published: November 2006

AbstractThe mono(alkyl)bis(phenoxido)titanium complexes [TiR′(η5‐C5R5)(η2‐mbmp)] [R = H, R′ = Me (4), CH2Ph (5), Ph (6), CH2SiMe3 (7); R = Me, R′ = Me (8), CH2Ph (9), CH2SiMe3 (10); η2‐mbmp = 2,2′‐methylenebis(6‐tert‐butyl‐4‐methylphenoxido)] have been prepared in good yields by reaction of the appropriate alkylating reagent with the corresponding chlorido(cyclopentadienyl)bis(phenoxido)titanium derivative. Compound 6 reacts in toluene with traces of water to afford the μ‐oxidotitanium complex {Ti(η5‐C5H5)(η2‐mbmp)}2(μ‐O) (11). Compounds 8, 9 and 11 have been characterised by single‐crystal X‐ray crystallography, and density functional calculations have been performed in order to elucidate the energetic and structural properties of these compounds. The activity of these complexes in the presence of methylaluminoxane (MAO), B(C6F5)3 or [Ph3C][B(C6F5)4] as co‐catalysts in the polymerisation of propylene and styrene has been studied. In an effort to model the nature of the catalytic species generated from these precursors, the reactions of the mono(cyclopentadienyl)bis(phenoxido)chlorido‐ and‐alkyltitanium derivatives with Lewis acids were examined. B(C6F5)3 reacts with the neutral complexes [TiR′(η5‐C5R5)(η2‐mbmp)] by abstraction of the alkyl group R′ to give the highly stable species [Ti(η5‐C5H5)(η2‐mbmp)][MeB(C6F5)3] (12), [Ti(η5‐C5H5)(η2‐mbmp)][(PhCH2)B(C6F5)3] (13), [Ti(η5‐C5Me5)(η2‐mbmp)][MeB(C6F5)3] (14) and [Ti(η5‐C5Me5)(η2‐mbmp)][(PhCH2)B(C6F5)3] (15), which are inactive in propylene and styrene polymerisation. In contrast, the reaction between the neutral alkyl derivatives and [CPh3][B(C6F5)4] affords species that are active in α‐olefin polymerisation. Treatment of the mono(chlorido) compound [TiCl(η5‐C5H5)(η2‐mbmp)] with 1 equiv. of AlMe3 affords the methyl derivative 4 as essentially the only reaction product. When an excess of AlMe3 is used, transmetallation reactions of the bis(phenoxido) ligand from titanium to aluminium are observed. Reactions of the bis(phenol) mbmpH2 with AlMe3 or AlClMe2 yield [AlMe(mbmp)]2 (16) and [AlCl(mbmp)]2 (17). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
R(Ar)O–N2+ vs. R(Ar)–N2O+: Are Alkoxy‐(Aryloxy‐)diazonium Ions or Alkyl‐(Aryl‐)N‐nitroso‐onium Ions Formed in the Gas‐Phase Reactions of N2O with H+, Me+, Ph+, PhCH2+, Tr+ and PhCO+?
Authors: Cabrini Liliane G. , Benassi Mario , Eberlin Marcos N. , Okazaki Takao , Laali Kenneth K. 
Published: November 2006

AbstractGas‐phase reactions of N2O with H+, Me+, Ph+, PhCH2+, Tr+ (the tropylium ion) and PhCO+ were studied by pentaquadrupole mass spectrometry. Collision‐induced dissociation (CID) of the product ions establishes that, in the diluted solvent and counterion‐free MS environment, gaseous Me+ and Ph+ ions form preferentially Me(Ph)O–N2+ (electrophilic attack at oxygen), whereas PhCH2+ forms preferentially PhCH2–N2O+ (electrophilic attack at nitrogen). The nascent phenoxydiazonium ion PhO–N2+ dissociates promptly by N2 loss to form PhO+ as the observable addition product. The PhCO+ and Tr+ ions are unreactive towards addition to N2O. The CID and ion/molecule chemistry of [N2O + H]+ are inconclusive with regard to connectivity, because the ion is rather resistant towards dissociation and reacts essentially as a proton donor species. Gaseous MeO–N2+ is not only efficient as a methylating agent towards ethers, heteroaromatics and nitriles, but also displays a rich chemistry that includes polar [4+2+] stepwise cycloadditions with representative dienes and polar transacetalization with cyclic acetals. Relative energies and geometries of various RO–N2+/R–N2O+ isomeric pairs were evaluated by MP2 and DFT calculations.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Synthesis of a Benzolactone Collection using Click Chemistry
Authors: Ritschel Jan , Sasse Florenz , Maier Martin E. 
Published: November 2006

AbstractA collection of benzotriazoles consisting of seven compounds was prepared from the propynyl‐substituted benzolactone 1 and various azides using click chemistry. The lactone 1 was obtained through a short route by direct esterification of the allylbenzoic acid 9 with the alkynol 7 giving the benzoate 2. The homopropargyl alcohol 7 in turn was obtained by opening the epoxide 6 with triisopropylsilyl acetylide. Ring‐closing metathesis of the ester 2 using Grubbs catalyst II followed by removal of the silicon protecting group furnished the lactone 1. Two of the benzotriazoles, 17a and 17b, were also converted into the corresponding phenols to probe the role of the phenolic OH on the biological activity. All nine benzotriazoles showed cytotoxic activity in a L929 mouse fibroblast assay with IC50 values in the low micromolar range. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
α‐Haloenol Acetates: Versatile Reactants for Oxetan‐2‐one, Azetidin‐2‐one and Isoxazolidin‐5‐one Synthesis
Authors: Bejot Romain , Anjaiah Siddam , Falck J. R. , Mioskowski Charles 
Published: November 2006

AbstractNew ketene equivalents, namely α‐haloenol acetates, are investigated as both nucleophilic and electrophilic reactants in a tandem aldol–lactonization reaction. Diethylaluminum ethoxide proves to be an efficient promoter for the aldol reaction with a wide range of substrates, including inter alia, aldehydes, ketones, imines, nitrones and oximes, leading to oxetan‐2‐ones, azetidin‐2‐ones and isoxazolidin‐5‐ones. The resultant heterocyclic adducts are common structural elements in numerous compounds of interest as well as key intermediates in the preparation of other functionalities. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Mit dem Laser gegen Blitz und Donner
Authors: Wöste Ludger H. , Sauerbrey Roland 
Published: November 2006

AbstractMit den ultrakurzen Lichtblitzen eines Hochleistungslasers lassen sich ausgedehnte Plasmakanäle in der Luft erzeugen. Sie können nicht nur in der Atmosphärenforschung helfen, sondern auch den Gewitterschutz verbessern
Vom großen Nutzen kleinster Partikel
Authors: Odenbach Stefan 
Published: November 2006

AbstractMithilfe magnetischer Felder können Kräfte auf Ferrofluide ausgeübt werden. Dies macht sich auch die biomedizinische Forschung zunutze. So werden neuartige Therapieformen zur Bekämpfung von Krebserkrankungen unterstützt
Molecular characterization of a t(9;12)(p21;q13) balanced chromosome translocation in combination with integrative genomics analysis identifies C9orf14 as a candidate tumor‐suppressor
Authors: Pujana Miguel Angel , Ruiz Anna , Badenas Cèlia , Puig‐Butille Josep‐Anton , Nadal Marga , Stark Mitchell , Gómez Laia , Valls Joan , Solé Xavier , Hernández Pilar , Cerrato Celia , Madrigal Irene , de Cid Rafael , Aguilar Helena , Capellá Gabriel , Cal Santiago , James Michael R. , Walker Graeme J. , Malvehy Josep , Milà Montserrat , Hayward Nicholas K. , Estivill Xavier , Puig Susana 
Published: November 2006

AbstractA large number of nevi (LNN) is a high risk phenotypic trait for developing cutaneous malignant melanoma (CMM). In this study, the breakpoints of a t(9;12)(p21;q13) balanced chromosome translocation were finely mapped in a family with LNN and CMM. Molecular characterization of the 9p21 breakpoint identified a novel gene C9orf14 expressed in melanocytes disrupted by the translocation. Integrative analysis of functional genomics data was applied to determine the role of C9orf14 in CMM development. An analysis of genome‐wide DNA copy number alterations in melanoma tumors revealed the loss of the C9orf14 locus, located proximal to CDKN2A, in approximately one‐fourth of tumors. Analysis of gene expression data in cancer cell lines and melanoma tumors suggests a loss of C9orf14 expression in melanoma tumorigenesis. Taken together, our results indicate that C9orf14 is a candidate tumor‐suppressor for nevus development and late stage melanoma at 9p21, a region frequently deleted in different types of human cancers. © 2006 Wiley‐Liss, Inc.
Family‐based association analysis with ordered categorical phenotypes, covariates and interactions
Authors: Baksh M. Fazil , Balding David J. , Vyse Timothy J. , Whittaker John C. 
Published: November 2006

AbstractGenetic association analyses of family‐based studies with ordered categorical phenotypes are often conducted using methods either for quantitative or for binary traits, which can lead to suboptimal analyses. Here we present an alternative likelihood‐based method of analysis for single nucleotide polymorphism (SNP) genotypes and ordered categorical phenotypes in nuclear families of any size. Our approach, which extends our previous work for binary phenotypes, permits straightforward inclusion of covariate, gene‐gene and gene‐covariate interaction terms in the likelihood, incorporates a simple model for ascertainment and allows for family‐specific effects in the hypothesis test. Additionally, our method produces interpretable parameter estimates and valid confidence intervals. We assess the proposed method using simulated data, and apply it to a polymorphism in the c‐reactive protein (CRP) gene typed in families collected to investigate human systemic lupus erythematosus. By including sex interactions in the analysis, we show that the polymorphism is associated with anti‐nuclear autoantibody (ANA) production in females, while there appears to be no effect in males.Genet. Epidemiol. 2006. © 2006 Wiley‐Liss, Inc.
Genetic influences on mannan‐binding lectin (MBL) and mannan‐binding lectin associated serine protease‐2 (MASP‐2) activity
Authors: Sorensen Grith L. , Petersen Inge , Thiel Steffen , Fenger Mogens , Christensen Kaare , Kyvik Kirsten O. , Sørensen Thorkild I. A. , Holmskov Uffe , Jensenius Jens Christian 
Published: November 2006

AbstractThe lectin pathway of the complement system is activated when Mannan‐binding lectin (MBL) in complex with MASP‐2 binds microorganisms. Polymorphisms in both genes are responsible for low serum levels, which associate with increased risk of infection and autoimmune disease. The present study includes 1215 MBL measurements and 1214 MASP‐2 activity measurements in healthy Danish adult twins. Total MASP‐2 activity was estimated by C4 cleaving activity of samples diluted in an excess of MBL. Twin‐twin correlations were higher in monozygotic (MZ) than in dizygotic (DZ) twins for both traits. Heritabilites of MBL levels and MASP‐2 activity were estimated using structural equation modeling allowing assessment of the contribution of common genes affecting both traits. The estimated heritability was 0.77 [95% CI 0.64;0.91] for MBL levels and 0.75 [95% CI 0.59;0.81] for MASP‐2 activity with the presence of additive genetic factors, shared environmental factors, and non‐shared environmental factors. The genetic correlation, i.e., common genetic factors affecting MBL and MASP‐2 activity was estimated to rg = 0.34 [0.25;0.42]. The data indicate a strong genetic influence for the serum levels of MBL and for MASP‐2 activity with a significant genetic correlation between the two traits. Genet. Epidemiol. © 2006 Wiley‐Liss, Inc.
T cells contribute to lysophosphatidylcholine‐induced macrophage activation and demyelination in the CNS
Authors: Ghasemlou Nader , Jeong Suh Young , Lacroix Steve , David Samuel 
Published: November 2006

AbstractWe have previously shown that intraspinal microinjection of lysophosphatidylcholine (LPC), a potent demyelinating agent, results in a rapid but brief influx of T cells (between 6 and 12 h). This is accompanied by a robust activation of macrophages/microglia that leads to demyelination by 48 h. In the present study, we examined whether this brief influx of T cells contributes to the activation of macrophages/microglia and demyelination by injecting LPC into the dorsal column white matter of athymic Nude mice that lack T cells. We show that there is a significant reduction in macrophage/microglial activation and myelin clearance after LPC injection in Nude mice as compared with wildtype controls. We also show that there is no difference in the recruitment of hematogenous macrophages into the spinal cord after LPC injection in the two mouse strains. Of the T cell cytokines assessed, there was a marked reduction in the mRNA expression of interleukin‐2 (IL‐2) in Nude mice compared with wildtype animals. Neutralizing IL‐2 with function‐blocking antibodies in wildtype animals resulted in a significant decrease in the number of phagocytic macrophages/microglia and a reduction in demyelination induced by LPC. While there may be other defects in Nude mice that might contribute to the effects shown here, these data suggest that the brief influx of T cells in this model of chemically‐induced demyelination could play a role in macrophage/microglial activation and demyelination. These results may also have implications for remyelination in this and other types of CNS damage. © 2006 Wiley‐Liss, Inc.
The development of hippocampal interneurons in rodents
Authors: Danglot Lydia , Triller Antoine , Marty Serge 
Published: November 2006

AbstractInterneurons are GABAergic neurons responsible for inhibitory activity in the adult hippocampus, thereby controlling the activity of principal excitatory cells through the activation of postsynaptic GABAA receptors. Subgroups of GABAergic neurons innervate specific parts of excitatory neurons. This specificity indicates that particular interneuron subgroups are able to recognize molecules segregated on the membrane of the pyramidal neuron. Once these specific connections are established, a quantitative regulation of their strength must be performed to achieve the proper balance of excitation and inhibition. We will review when and where interneurons are generated. We will then detail their migration toward and within the hippocampus, and the maturation of their morphological and neurochemical characteristics. We will finally review potential mechanisms underlying the development of GABAergic interneurons. © 2006 Wiley‐Liss, Inc.
From grid cells to place cells: A mathematical model
Authors: Solstad Trygve , Moser Edvard I. , Einevoll Gaute T. 
Published: November 2006

AbstractAnatomical connectivity and recent neurophysiological results imply that grid cells in the medial entorhinal cortex are the principal cortical inputs to place cells in the hippocampus. The authors propose a model in which place fields of hippocampal pyramidal cells are formed by linear summation of appropriately weighted inputs from entorhinal grid cells. Single confined place fields could be formed by summing input from a modest number (10–50) of grid cells with relatively similar grid phases, diverse grid orientations, and a biologically plausible range of grid spacings. When the spatial phase variation in the grid‐cell input was higher, multiple, and irregularly spaced firing fields were formed. These observations point to a number of possible constraints in the organization of functional connections between grid cells and place cells. © 2006 Wiley‐Liss, Inc.
αvβ3 Integrin‐targeting of intraperitoneally growing tumors with a radiolabeled RGD peptide
Authors: Dijkgraaf Ingrid , Kruijtzer John A.W. , Frielink Cathelijne , Corstens Frans H.M. , Oyen Wim J.G. , Liskamp Rob M.J. , Boerman Otto C. 
Published: November 2006

AbstractOvarian cancer is the fourth most common cause of cancer deaths among females in the western world after cancer of the breast, colon and lung. The inability to control the disease within the peritoneal cavity is the major cause of treatment failure in patients with ovarian cancer. The majority of ovarian carcinomas express the αvβ3 integrin. Here we studied the tumor targeting potential of an 111In‐labeled cyclic RGD peptide in athymic BALB/c mice with intraperitoneally (i.p.) growing NIH:OVCAR‐3 human ovarian carcinoma tumors. The cyclic RGD peptide, c(RGDfK)E, was synthesized, conjugated with DOTA and radiolabeled with 111In. The targeting potential of 111In‐DOTA‐E‐c(RGDfK) was studied in athymic mice with i.p. growing NIH:OVCAR‐3 xenografts and the optimal dose of this compound was determined (0.01 μg up to 10 μg). The biodistribution at optimal peptide dose was determined at various time points (0.5 up to 72 hr). Furthermore, the therapeutic potential of 177Lu‐DOTA‐E‐c(RGDfK) was studied in this model. Two hours after i.p. administration, 111In‐DOTA‐E‐c(RGDfK) showed high and specific uptake in the i.p. growing tumors. Optimal uptake in the i.p. growing tumors was observed at a 0.03–0.1 μg dose range. Tumor uptake of 111In‐DOTA‐E‐c(RGDfK) peaked 4 hr p.i. [(38.8 ± 2.7)% ID/g], gradually decreasing at later time points [(24.0 ± 4.1)% ID/g at 48 hr p.i.]. Intraperitoneal growth of OVCAR‐3 could be significantly delayed by injecting 37 MBq 177Lu‐labeled peptide i.p. Radiolabeled DOTA‐E‐c(RGDfK) is suitable for targeting of i.p. growing tumors and potentially can be used for peptide receptor radionuclide therapy of these tumors. © 2006 Wiley‐Liss, Inc.
TGFβ1 and TGFα contrarily affect alveolar survival and tumorigenesis in mouse mammary epithelium
Authors: Booth Brian W. , Jhappan Chamelli , Merlino Glenn , Smith Gilbert H. 
Published: November 2006

AbstractGrowth factors and hormones are responsible for development of the mammary gland and can contribute to mammary carcinogenesis. The transforming growth factors (TGF) α and β1 demonstrate opposing effects on the mammary epithelium. TGFα is a mitogen and survival factor for mammary secretory cells and is often upregulated in cancer, while TGFβ1 may act as a growth suppressor and has been shown to inhibit alveolar development and lactogenesis. To examine the contradistinct effects of TGFα and TGFβ1 on normal mammary epithelium, we crossed MT‐TGFα mice with WAP‐TGFβ1 transgenic mice. The newly generated bitransgenic mice failed to nurse their pups and were resistant to mammary tumorigenesis (0% at 12 months of age), compared to single transgenic MT‐TGFα in which the majority (65% at 12 months of age) of the mice developed hyperplastic alveolar mammary lesions. Transplantation studies showed that bitransgenic tissue was highly resistant to tumor formation even after multiple pregnancies. WAP‐TGFβ1 mammary transplants often failed to grow and fully fill cleared mammary fat pads upon transplantation. This repression of growth was completely reversed in the bitransgenic implants, which grew as well as normal epithelium upon transplantation. In addition, TGF and bitransgenic TGFα/TGFβ1 mice had reduced rates of apoptosis during involution as compared to wild type and TGFβ1. These data demonstrate that TGFβ1 and TGFα exhibit opposing effects upon the proliferation and survival of mammary epithelium when expressed alone but when expressed together result in reciprocally suppressive effects upon one another in the context of mammary development and tumorigenesis. © 2006 Wiley‐Liss, Inc.
Ala394Thr polymorphism in the clock gene NPAS2: A circadian modifier for the risk of non‐Hodgkin's lymphoma
Authors: Zhu Yong , Leaderer Derek , Guss Carly , Brown Heather N. , Zhang Yawei , Boyle Peter , Stevens Richard G. , Hoffman Aaron , Qin Qin , Han Xuesong , Zheng Tongzhang 
Published: November 2006

AbstractCircadian disruption is theorized to cause immune dysregulation, which is the only established risk factor for non‐Hodgkin's lymphoma (NHL). Genes responsible for circadian rhythm are also involved in cancer‐related biological pathways as potential tumor suppressors. However, no previous studies have examined associations between circadian genes and NHL risk. In this population‐based case control study (n = 455 cases; 527 controls), we examined the only identified nonsynonymous polymorphism (Ala394Thr; rs2305160) in the largest circadian gene, neuronal PAS domain protein 2 (NPAS2), in order to examine its impact on NHL risk. Our results demonstrate a robust association of the variant Thr genotypes (Ala/Thr and Thr/Thr) with reduced risk of NHL (OR = 0.66, 95% CI: 0.51–0.85, p = 0.001), especially B‐cell lymphoma (OR = 0.61, 95% CI: 0.47–0.80, p ≤≤ 0.0001). These findings provide the first molecular epidemiologic evidence supporting a role of circadian genes in lymphomagenesis, which suggests that genetic variations in circadian genes might be a novel panel of promising biomarkers for NHL and warrants further investigation. © 2006 Wiley‐Liss, Inc.