bluuebunny/crossref_metadata_2025_split huggingface dataset:
In vivo and in vitro analysis of the vasculogenic potential of avian proepicardial and epicardial cells†
Authors: Guadix Juan A. , Carmona Rita , Muñoz‐Chápuli Ramón , Pérez‐Pomares José M. 
Published: February 2006

AbstractCoronary vessel formation is a special case in the context of embryonic vascular development. A major part of the coronary cellular precursors (endothelial, smooth muscle, and fibroblastic cells) derive from the proepicardium and the epicardium in what can be regarded as a late event of angioblastic and smooth muscle cell differentiation. Thus, coronary morphogenesis is dependent on the epithelial–mesenchymal transformation of the proepicardium and the epicardium. In this study, we present several novel observations about the process of coronary vasculogenesis in avian embryos, namely: (1) The proepicardium displays a high vasculogenic potential, both in vivo (as shown by heterotopic transplants) and in vitro, which is modulated by vascular endothelial growth factor (VEGF) and basic fibroblast growth factor signals; (2) Proepicardial and epicardial cells co‐express receptors for platelet‐derived growth factor‐BB and VEGF; (3) Coronary angioblasts (found all through the epicardial, subepicardial, and compact myocardial layers) express the Wilms' tumor associated transcription factor and the retinoic acid‐synthesizing enzyme retinaldehyde‐dehydrogenase‐2, two markers of the coelomic epithelium involved in coronary endothelium development. All these results contribute to the development of our knowledge on the vascular potential of proepicardial/epicardial cells, the existent interrelationships between the differentiating coronary cell lineages, and the molecular mechanisms involved in the regulation of coronary morphogenesis. Developmental Dynamics 235:1014–1026, 2006. © 2006 Wiley‐Liss, Inc.
Neuronal leucine‐rich repeat 6 (XlNLRR‐6) is required for late lens and retina development in Xenopus laevis
Authors: Wolfe Adam D. , Henry Jonathan J. 
Published: February 2006

AbstractLeucine‐rich repeat proteins expressed in the developing vertebrate nervous system comprise a complex, multifamily group, and little is known of their developmental function in vivo. We have identified a novel member of this group in Xenopus laevis, XlNLRR‐6, and through sequence and phylogenetic analysis, have placed it within a defined family of vertebrate neuronal leucine‐rich repeat proteins (NLRR). XlNLRR‐6 is expressed in the developing nervous system and tissues of the eye beginning at the neural plate stage, and expression continues throughout embryonic and larval development. Using antisense morpholino oligonucleotide (MO) ‐mediated knockdown of XlNLRR‐6, we demonstrate that this protein is critical for development of the lens, retina, and cornea. Reciprocal transplantation of presumptive lens ectoderm between MO‐treated and untreated embryos demonstrate that XlNLRR‐6 plays autonomous roles in the development of both the lens and retina. These findings represent the first in vivo functional analysis of an NLRR family protein and establish a role for this protein during late differentiation of tissues in the developing eye. Developmental Dynamics 235:1027–1041, 2006. © 2006 Wiley‐Liss, Inc.
Multicolor in vivo time‐lapse imaging at cellular resolution by stereomicroscopy
Authors: Distel Martin , Babaryka Andreas , Köster Reinhard W. 
Published: February 2006

AbstractIntravital time‐lapse imaging has altered significantly many long‐standing rules of biological mechanisms, but being apparatus‐intense and laborious, time‐lapse imaging remained mostly restricted to specialized labs. We show that recently introduced fully automated fluorescence stereomicroscopes represent cost‐effective but powerful means of imaging dynamic events ranging from observing embryogenesis over several days to detailed tissue rearrangements and fast blood cell rolling in vivo. When combined with deconvolution approaches, even subcellular resolution in several colors can be achieved. Using three‐dimensional image recording, we show the spatial reconstruction of expression patterns. Furthermore, by combining three‐dimensional image recording over time with subsequent deconvolution analysis, we demonstrate that subcellular dynamics such as axonal pathfinding in vivo can be resolved. These findings promise that time‐lapse imaging using a stereomicroscope will become a hands‐on standard method for phenotype analysis in many fields of biology. Developmental Dynamics 235:1100–1106, 2006. © 2006 Wiley‐Liss, Inc.
Dlk1 expression marks developing endothelium and sites of branching morphogenesis in the mouse embryo and placenta
Authors: Yevtodiyenko Aleksey , Schmidt Jennifer V. 
Published: February 2006

AbstractThe protein product of the Delta‐like 1 (Dlk1) gene belongs to the Delta‐Notch family of signaling molecules, proteins involved in cell fate determination in many tissues during development. The DLK1 protein is believed to function as a growth factor, maintaining the proliferative state of undifferentiated cells, and is usually down‐regulated as immature cells differentiate. The expression pattern of the DLK1 protein has been described in certain human tissues; however, Dlk1 expression is not well understood in the mouse, the most tractable mammalian genetic model system. To better understand the role of Dlk1 in embryonic development, the tissue‐specific expression pattern of Dlk1 mRNA during mouse embryogenesis was analyzed by in situ hybridization. In embryonic day 12.5 (e12.5) embryos, high levels of Dlk1 were found in the developing pituitary, pancreas, lung, adrenal, and many mesodermally derived tissues. Strikingly, Dlk1 expression also marks the growing branches of organs that develop through the process of branching morphogenesis. At e16.5, Dlk1 expression is down‐regulated in most tissues but remains in the pituitary, the adrenal gland, and in skeletal muscle. In the placenta, expression of Dlk1 is detected in endothelial cells lining the fetal blood vessels of the labyrinth. This pattern is distinct from that seen in the human placenta and suggests a role for Dlk1 in regulating maternal–fetal interactions. Developmental Dynamics 235:1115–1123, 2006. © 2006 Wiley‐Liss, Inc.
Anatomy of T cell autoimmunity to myelin oligodendrocyte glycoprotein (MOG): Prime role of MOG44F in selection and control of MOG‐reactive T cells in H‐2b mice
Authors: Ben‐Nun Avraham , de Rosbo Nicole Kerlero , Kaushansky Nathali , Eisenstein Miriam , Cohen Lydia , Kaye Joel F. , Mendel Itzhack 
Published: February 2006

AbstractMyelin oligodendrocyte glycoprotein (MOG) is an important myelin target antigen, and MOG‐induced EAE is now a widely used model for multiple sclerosis. Clonal dissection revealed that MOG‐induced EAE in H‐2b mice is associated with activation of an unexpectedly large number of T cell clones reactive against the encephalitogenic epitope MOG35–55. These clones expressed extremely diverse TCR with no obvious CDR3α/CDR3β motif(s). Despite extensive TCR diversity, the cells required MOG40–48 as their common core epitope and shared MOG44F as their major TCR contact. Fine epitope‐specificity analysis with progressively truncated peptides suggested that the extensive TCR heterogeneity is mostly related to differential recognition of multiple overlapping epitopes nested within MOG37–52, each comprised of a MOG40–48 core flanked at the N‐ and/or the C‐terminus by a variable number of residues important for interaction with different TCR. Abrogation of both the encephalitogenic potential of MOG and T cell reactivity against MOG by a single mutation (MOG44F/MOG44A), together with effective down‐regulation of MOG‐induced EAE by MOG37–44A–52, confirmed in vivo the primary role for MOG44F in the selection/activation of MOG‐reactive T cells. We suggest that such a highly focused T cell autoreactivity could be a selective force that offsets the extensive TCR diversity to facilitate a more “centralized control” of pathogenic MOG‐related T cell autoimmunity.
Endogenous cortisol determines the circadian rhythm of lipopolysaccharide‐ but not lipoteichoic acid‐inducible cytokine release
Authors: Hermann Corinna , von Aulock Sonja , Dehus Oliver , Keller Moritz , Okigami Hiromi , Gantner Florian , Wendel Albrecht , Hartung Thomas 
Published: February 2006

AbstractTo investigate the circadian rhythm of inducible cytokine release and a potential pacemaker role of endogenous cortisol, cortisol levels as well as cytokine release from ex vivo LPS‐stimulated blood were assessed at 4‐h intervals over 24 h in 11 volunteers. We found a significant diurnal variation for IFN‐γ and IL‐8, and a tendency for TNF, all inversely correlated to the serum cortisol levels, but no evidence for such a rhythm for IL‐1β and IL‐6. In vitro IC50 values for cytokine inhibition by hydrocortisone (HC) corresponded to the observed rank order for circadian rhythmicity. mRNA analyses revealed that this was due to a reduction of gene transcription. These effects of HC were significantly reversed by the glucocorticoid receptor antagonist RU486. Supplementation of HC in vivo to maintain morning cortisol levels throughout the day blunted the circadian rhythm of ex vivo LPS‐induced cytokines. Surprisingly, no significant diurnal variation for any investigated cytokine was found in the same volunteer group upon stimulation with lipoteichoic acid (LTA), the gram‐positive counterpart to LPS. Furthermore, 10–50‐fold higher HC concentrations as compared to LPS were required to block LTA‐induced cytokine release. LTA, in contrast to LPS, failed to activate Jun kinase, a reported target for HC action.
Pathogen‐specific TLR signaling in mucosa: Mutual contribution of microbial TLR agonists and virulence factors
Authors: Sirard Jean‐Claude , Bayardo Mariela , Didierlaurent Arnaud 
Published: February 2006

AbstractDetection of microorganisms through microbe‐associated molecular patterns (MAMP) by Toll‐like receptors (TLR) is crucial to trigger protective immunity. In the mucosa, sentinel cells are exposed to MAMP from both pathogens and commensals; however, the TLR response is tightly controlled to avoid inflammation in response to commensals. Uropathogenic Escherichia coli (UPEC) trigger innate responses during urinary tract infection in a TLR4‐dependent and CD14‐independent manner. UPEC express virulence factors, such as type 1 fimbriae and/or P fimbriae, allowing bacterial attachment to the epithelium. In this issue of the European Journal of Immunology, Fisher et al. show that fimbriae are required to induce a TLR4‐specific epithelial response. Depending on the fimbriae expressed by UPEC, different adaptor molecules are involved in TLR4 signaling. These data add to the recent body of evidence suggesting that TLR responses are regulated by co‐receptors, such as receptors for virulence factors. In conclusion, the “pathogenic” TLR stimulation provides a novel way for the host to ignore commensal bacteria.See accompanying article http://dx.doi.org/10.1002/eji.200535149
Charge‐Transfer Phase Transition and Ferromagnetism of Iron Mixed‐Valence Complexes (n‐CnH2n+1)4N[FeIIFeIII(dto)3] (n = 3–6; dto = C2O2S2)
Authors: Itoi Miho , Ono Yuuki , Kojima Norimichi , Kato Kenichi , Osaka Keiichi , Takata Masaki 
Published: February 2006

AbstractThe iron mixed‐valence complex, (n‐C3H7)4N[FeIIFeIII(dto)3] (dto = dithiooxalato) shows a charge‐transfer (CT) phase transition at TCT = 122.4 K. In the vicinity of TCT, the spin state changes from FeII (S = 2) – FeIII (S = 1/2) (high‐temperature phase: HTP) to FeII (S = 0) – FeIII (S = 5/2) (low‐temperature phase: LTP) accompanied by a charge transfer between FeII and FeIII. This complex also undergoes a ferromagnetic transition at 7 K in the LTP. In order to investigate the mechanism of the CT phase transition and the ferromagnetism, we have systematically synthesized (n‐CnH2n+1)4N[FeIIFeIII(dto)3] (n = 3–6), and have investigated their physical properties by magnetic susceptibility, powder X‐ray diffraction measurements, and ESR spectroscopy. The compounds (n‐CnH2n+1)4N[FeIIFeIII(dto)3] (n = 3–6) display ferromagnetic phase transitions at 7 K, 7 K (& 13 K), 19.5 K, and 22 K, respectively. For n = 3 and 4, the CT phase transitions take place at TCT ≈ 120 K and TCT ≈ 140 K, respectively. For n = 5 and 6, on the other hand, the CT phase transition does not occur, and the spin configuration of FeII (S = 2) and FeIII (S = 1/2) corresponding to the HTP for n = 3 and 4 is stable between 2 K and 300 K. The cation size of (n‐CnH2n+1)4N+ (n = 3–6) acts as an effective internal pressure which induces the CT phase transition and the ferromagnetic ordering in the [FeIIFeIII(dto)3]–∞ layer. We also discuss the mechanism of the CT phase transition and the ferromagnetism induced by the charge‐transfer interaction between FeII and FeIII. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Synthesis, Structures, and Luminescent Properties of Aluminum Complexes with Chelating Anilido‐Imine Ligands
Authors: Liu Xiaoming , Xia Hong , Gao Wei , Ye Ling , Mu Ying , Su Qing , Ren Yi 
Published: February 2006

AbstractThe syntheses of a number of four‐coordinate aluminum complexes, ortho‐C6H4(NAr′)(CH=NAr′′)AlCl2 [Ar′ = Ar′′ = 2,6‐iPr2C6H3 (2a); Ar′ = 2,6‐iPr2C6H3, Ar′′ = 2,6‐Me2C6H3 (2b); Ar′ = Ar′′ = 2,6‐Me2C6H3 (2c); Ar′ = p‐MeC6H4, Ar′′ = 2,6‐iPr2C6H3 (2d)], are described. Complexes 2a–2d were synthesized from the reaction of AlCl3 with lithium salt of the corresponding ligand at room temperature. All complexes were characterized by 1H and 13C NMR spectroscopy and molecular structures of complexes 2a, 2b, and 2d were determined by X‐ray crystallography. Luminescent properties of complexes 2a–2d in both solution and the solid state were studied. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Optical Properties of the Perovskite Solid Solution LaTiO2N–ATiO3(A = Sr, Ba)
Authors: Cheviré François , Tessier Franck , Marchand Roger 
Published: February 2006

AbstractStarting from the colored oxynitride LaTiO2N, new perovskite‐type solid solutions have been evidenced in the systems La1–xAxTiO2+xN1–x (A = Sr, Ba) by ammonolysis at 950 °C of the corresponding oxide precursors prepared by the molten salt route. The color of the resulting powders varies progressively from the brown of LaTiO2N to the white of the oxide with a decrease in both the nitrogen and lanthanum contents. The optical absorption was characterized by diffuse reflectance. The nonlinear variation of the optical bandgap may result from the competition between the variation of the inductive effect between lanthanum and strontium, structural changes, and the difference in electronegativity between nitrogen and oxygen. For the compounds with a low nitrogen content the observed green shade is attributed to the presence of a nitrogen‐rich secondary phase: TiOxNy in which titanium presents a mixed‐valence state. Taking advantage of a chimie douce process, the amorphous citrate route, the highest oxidation state of titanium was stabilized until x = 0.9 in the La0.1Sr0.9Ti(O,N)3 phase giving the powder a bright yellow color (Eg = 2.49 eV). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Atmospheric Pressure Chemical Vapour Deposition of NbSe2 Thin Films on Glass
Authors: Boscher Nicolas D. , Carmalt Claire J. , Parkin Ivan P. 
Published: February 2006

AbstractAtmospheric pressure chemical vapour deposition (APCVD) of niobium selenide films on glass substrates was achieved by reaction of di‐tert‐butyl selenide with NbCl5 at 250–600 °C. X‐ray diffraction showed that the NbSe2 films were crystalline and of the 2Ha poly‐type with cell constants close to those expected (a = 3.44 Å; c = 12.58 Å). Marked preferred orientation along either (101) or (200) was noted at higher deposition temperature and this unexpectedly varied depending on distance from the reactor inlet. The films produced at 600 °C showed exactly the Nb/Se ratio expected for NbSe2 by energy dispersive analysis by X‐rays. The films deposited at the substrate temperatures of 500 °C or less were selenium rich with a niobium to selenium ratio of 1:2.5. The films produced at 600 °C were dark‐green, powdery and poorly adhesive. The films produced at 500 °C and below were dark‐brown matte in appearance, they passed the Scotch tape test, but could be scratched with a steel scalpel. SEM showed that the films were composed of plate‐like crystals, which become longer and thicker with increasing deposition temperature. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Oxidative Addition of Cl2, HClO to Square‐Planar PtII Complexes: Synthesis and Structural Characterization of Platinum(II) and Platinum(IV) Bis(amidate) Complexes
Authors: Liu Fenghui , Chen Wanzhi 
Published: February 2006

AbstractNew bis(amidate)platinum(II) complexes with the general formula cis‐[Pt(RNH2)2(NHCOtBu)2] were prepared by the hydrolysis of the corresponding cis‐[Pt(RNH2)2(tBuCN)2]2+ complex. The bis(amidate)platinum(IV) complexes with the formula trans,cis,cis‐[PtCl2(RNH2)2(NHCOtBu)2] (5: R = H, 6: R = Et), trans,cis,cis‐[PtCl(OH)(RNH2)2(NHCOtBu)2] (8: R = H, 9: R = Et, and 10: 2 R = 1,2‐cHex), and mono(amidate) complex mer‐[PtCl3(DACH)(NHCOtBu)2] (7, DACH = trans‐1,2‐diaminocyclohexane) have been generated selectively by the oxidative addition of Cl2 and HClO to the corresponding platinum(II) complexes, [Pt(RNH2)2(NHCOtBu)2], in water. All the prepared compounds were characterized byelemental analyses and 1H and 195Pt NMR spectroscopy.The structures of trans,cis,cis‐[PtCl2(NH3)2(NHCOtBu)2] (5), trans,cis,cis‐[PtCl2(EtNH2)2(NHCOtBu)2] (6), mer‐[PtCl3(DACH)(NHCOtBu)] (7), and trans,cis,cis‐[PtCl(OH)(DACH)(NHCOtBu)2] (10) have been confirmed by X‐ray diffraction analyses. The structures of these platinum(IV) complexes adopt an octahedral geometry. The Pt–N, Pt–O, and Pt–Cl distances are in the expected ranges. These complexes are rare examples of bis(amidate)‐ and mono(amidate)platinum(IV) complexes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Counteranion‐Induced Formation of cis and trans Singly and Doubly H2biim‐Bridged Di‐, Hexa‐, and Polymeric Ag–H2biim Complexes
Authors: Sang Rui‐Li , Xu Li 
Published: February 2006

AbstractA series of cis and trans singly and doubly H2biim‐bridged di‐, hexa‐, and polymeric complexes of silver(I) (H2biim = 2,2′‐biimidazole), namely [Ag2(μ‐H2biim)2]SO4·2H2O (1),[Ag2(μ‐H2biim)2(μ‐ox)]n (2), [Ag6(μ‐H2biim)5(H2biim)2](ClO4)4(CH3CO2)2·2H2O (3), and [Ag(μ‐H2biim)(nicotinate)]n (4) have been synthesized and characterized by X‐ray crystallography and IR and photoluminescence spectroscopy. The structural topology of the Ag–H2biim system is determined by the charge of the counteranions. Thus, dianionic counterions facilitate the formation of dimeric structures driven by the charge‐balance requirement, whereas a monoanionic counterion favors the formation of helical structures. Counteranions of larger size lead to either finite helical structures or a trans arrangement of the coordinating nitrogen atoms because of steric requirements. Organic counteranions with a strong coordination ability bind to the Ag+ ions while inorganic counteranions are uncoordinated. The argentophilic attraction is not dominant in this system. Examination of the luminescent properties of H2biim and compounds 1–4 indicates that the fluorescence emission of H2biim is effectively shifted upon metal coordination. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Phosphorus‐Containing Dendrons: Synthesis, Reactivity, Properties, and Use as Building Blocks for Various Dendritic Architectures
Authors: Caminade Anne‐Marie , Maraval Alexandrine , Majoral Jean‐Pierre 
Published: February 2006

AbstractDendrons, also called dendritic wedges, are a special variety of dendrimers possessing one or two functional groups at the core, in addition to the numerous functional end groups. This review is focused on phosphorus‐containing dendrons, which are dendrons built with one phosphorus atom at each branching point. Their synthesis, reactivity and properties are described, with emphasis on their use as building blocks for the elaboration of very complex and original dendritic architectures. Electrochemical and catalytic properties, as well as examples in the field of materials are also given. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Analysis of the Synergistic Effect of Carbonylplatinum Complexes on the Iridium‐Catalysed Carbonylation of Methanol to Acetic Acid
Authors: Gautron Samuel , Lassauque Nicolas , Le Berre Carole , Serp Philippe , Azam Laurent , Giordano Roberto , Laurenczy Gábor , Thiébaut Daniel , Kalck Philippe 
Published: February 2006

AbstractHigh‐pressure NMR mechanistic investigations into the promoting role of dicarbonyldiiodoplatinum complex in the iridium‐catalysed carbonylation of methanol to acetic acid are consistent with iodide abstraction from the [IrI3(CH3)(CO)2]– resting state species by [PtI2(CO)2], unbolting the rate‐limiting migratory CO insertion step. A new [Ir–Pt] heterodimetallic complex, which presumably represents the key species involved in the abstraction of I–, has been characterised by NMR in tandem with FAB‐MS. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Hypercoordinated Organotin(IV) Halides Containing 2‐(Me2NCH2)C6H4 Groups: {2‐(Me2NCH2)C6H4}2SnX2 (X = F, Cl, Br, I) and {2‐(Me2NCH2)C6H4}R2SnX (R = Me, Ph; X = F, Cl, Br, I) and Their Solution Behaviour and Solid‐State, Hydrogen‐Bonding‐Based Supramolecular Architecture
Authors: Varga Richard A. , Rotar Adina , Schürmann Markus , Jurkschat Klaus , Silvestru Cristian 
Published: February 2006

AbstractThe hypercoordinated di‐ and triorganotin(IV) chlorides [{2‐(Me2NCH2)C6H4}2SnCl2] (1a) and [{2‐(Me2NCH2)C6H4}R2SnCl] [R = Me (2a), Ph (3a)] were prepared by treating SnCl4 or R2SnCl2 with [Li{2‐(Me2NCH2)C6H4}]. Halide‐exchange reactions between the organotin(IV) chlorides and the appropriate potassium halides gave [{2‐(Me2NCH2)C6H4}2SnX2] [X = F (1b), I (1d)], [{2‐(Me2NCH2)C6H4}Me2SnX] [X = F (2b), Br (2c), I (2d)] and [{2‐(Me2NCH2)C6H4}Ph2SnX] [X = F (3b), I (3d)]. Their solution behaviour was investigated by multinuclear (1H, 13C, 19F and 119Sn) NMR spectroscopy, including variable‐temperature studies. Single‐crystal X‐ray diffraction analyses revealed that the strong intramolecular coordination of the nitrogen atom from the pendant CH2NMe2 group to tin induces chirality. The influence of the identity and the number of the halogen atoms and the organic substituents at tin is discussed in relation with the hydrogen‐bonding network, which results in different supramolecular architectures in the crystal. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Boron–Nitrogen Adducts of 1,3,5‐Triaza‐7‐phosphaadamantane (PTA): Synthesis, Reactivity, and Molecular Structure
Authors: Frost Brian J. , Mebi Charles A. , Gingrich Phillip W. 
Published: February 2006

AbstractAddition of BH3 to 1,3,5‐triaza‐7‐phosphaadamantane (PTA) leads to the formation of the first coordination complex of PTA in which a nitrogen and not the phosphorus of PTA is involved in the bonding. Multinuclear NMR spectroscopy, X‐ray crystallography, and computational chemistry are utilized in the characterization of the products. Crystal structures of PTA–BH3 (1) and O=PTA–BH3 (2) adducts are described. In addition a coordination polymer, [CpRu(PTA)2Cl(Ph3B3O3)]n (3), resulting from Lewis acid–base adduct formation between the PTA ligands of CpRu(PTA)2Cl and the product of the cyclocondensation of phenylboronic acid is described. The polymeric compound 3 was also characterized by X‐ray crystallography. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)