bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aeration of Large Size Tanks by a Surface Agitator
Authors: Sardeing R. , Poux M. , Melen S. , Avrillier P. , Xuereb C. 
Published: April 2005

AbstractA new device has been developed in order to achieve urban or industrial wastewater biological treatment. It has been designed specially for lagoon applications to oxygenate and mix with the same apparatus. The goal is both to achieve a high gas flooding rate and to reach a maximal depth with the bubble plume. Mass transfer measurements have allowed us to choose the most appropriate geometry. Considering the application of the device and the possible use of low‐pressure O2 produced on‐site, the agitation system is located close to the liquid surface and is composed of a gas‐inducing turbine. The role of propellers in addition to the gas‐inducing turbine, as well as the use of baffles and a shell, have been experimentally studied. Numerical simulations (CFD) of the whole apparatus in single‐phase flow have been used to study the influence of the stator part of the geometry.
Optically Active Oligomer Units in Aggregates of a Highly Unsaturated, Optically Inactive Carotenoid Phospholipid
Authors: Foss Bente Jeanette , Sliwka Hans‐Richard , Partali Vassilia , Köpsel Christian , Mayer Bernhard , Martin Hans‐Dieter , Zsila Ferenc , Bikadi Zsolt , Simonyi Miklos 
Published: April 2005

AbstractEnantiomers of glycerophospholipids show low or no optical activity. Accordingly, optical activity was not observed with the R enantiomer of a highly unsaturated carotenoyl lysophospholipid in solution. In spite of this, strong Cotton effects are detected in water. The amphiphilic carotenoid–phospholipid monomers associate to form aggregates, whose optical activity is attributed to oligomeric entities. These small helical assemblies cannot exist independently. Yet, the calculated octamer represents the simplest repeating primary unit that sufficiently expresses the absorption properties and supramolecular optical activity.
Spectroscopic Evidence for a Dinitrogen Complex of Gallium and Estimation of the GaN2 Bond Strength
Authors: Himmel Hans‐Jörg , Hebben Nicole 
Published: April 2005

AbstractMatrix‐isolation experiments were performed to study the interaction between Ga atoms and N2 by using Raman and UV/Vis spectroscopies for detection and analysis. It was revealed that a weak complex is formed, for which resonance Raman spectra were obtained. Several overtones were sighted, allowing a rough estimate of the GaN2 fragmentation energy to be made (∼19 kJ mol−1). The excitation profile obtained from the spectra at different laser wavelengths agrees with the UV/Vis spectrum and shows that the complex exhibits an electronic transition at around 410 nm. At the Ga atom, this transition can be described as a 2S←2P or 2D←2P excitation, which is red‐shifted from its position for free Ga atoms (approximately 340 nm and 270 nm for 2S←2P and 2D←2P, respectively) as a result of N2 complexation. The effect of complexation involves, therefore, only slight stabilization of the 2P ground state but relatively strong stabilization of the excited 2S state. Accordingly, for the Ga atom in its excited 2S state, the GaN2 bond energy can be estimated to be around 79 kJ mol−1.
Electronic Structure, Spectra, and Magnetic Circular Dichroism of Cyclohexa‐, Cyclohepta‐, and Cyclooctapyrrole
Authors: Gorski Alexander , Köhler Thomas , Seidel Daniel , Lee Jeong Tae , Orzanowska Grażyna , Sessler Jonathan L. , Waluk Jacek 
Published: April 2005

AbstractThree recently obtained expanded porphyrins represent nice examples of compounds for which the electronic and spectral properties can be predicted from symmetry considerations alone. Perimeter‐model‐based theoretical analysis of the electronic structure of doubly protonated cyclo[6], cyclo[7], and cyclo[8]pyrrole leads to the anticipation of qualitatively the same electronic absorption and magnetic circular dichroism patterns for all three compounds. These predictions are fully confirmed by experiments, as well as DFT and INDO/S calculations. Due to a characteristic pattern of frontier molecular orbitals, a degenerate HOMO and a strongly split LUMO pair, the three cyclopyrroles show comparable absorption intensity in the Q and Soret regions. Magnetic circular dichroism spectra reveal both A and B Faraday terms, of which the signs and magnitudes are in remarkably good agreement with theoretical expectations. The values of the magnetic moments of the two lowest degenerate excited states have also been obtained.
High Affinity, Sequence Specific DNA Binding by Synthetic Tripyrrole–Peptide Conjugates
Authors: Blanco Juan B. , Vázquez Olalla , Martínez‐Costas José , Castedo Luis , Mascareñas José L. 
Published: April 2005

AbstractLinking the basic region of a bZIP transcription factor to a distamycin‐like tripyrrole peptide by means of a nitrogen‐containing tether produces a hybrid capable of high‐affinity recognition of specific, designated DNA sequences. The importance of the nitrogen in the tether is shown by the considerable reduction in affinity (more than 10‐fold) caused by its replacement with an ether linkage. Attachment of an aminopropyl chain on the pyrrole adjacent to the pyrrole bearing the nitrogen‐containing tether increases affinity approximately one order of magnitude. These results confirm that a suitable location of protonated amine groups on designed DNA‐binding peptides provides for higher affinities, most probably because of the generation of salt bridged contacts with the phosphodiester backbone.
Efficient Solid‐Phase Synthesis of Peptide‐Based Phosphine Ligands: Towards Combinatorial Libraries of Selective Transition Metal Catalysts
Authors: Christensen Christian A. , Meldal Morten 
Published: April 2005

AbstractA new methodology for the solid‐phase synthesis of peptide‐based phosphine ligands has been developed. Solid supported peptide scaffolds possessing either primary or secondary amines were synthesised using commercially available Fmoc‐protected amino acids and readily available Fmoc‐protected amino aldehydes for reductive alkylation, in standard solid‐phase peptide synthesis (SPPS). Phosphine moieties were introduced by phosphinomethylation of the free amines as the final solid‐phase synthetic step, immediately prior to complexation with palladium(II), thus avoiding tedious protection/deprotection of the phosphine moieties during the synthesis of the ligands. The extensive use of commercial building blocks and standard SPPS makes this methodology well suited for the generation of solid‐phase combinatorial libraries of novel ligands. Furthermore, it is possible to generate several different phosphine ligand libraries for every peptide scaffold library synthesised, by functionalising the scaffold libraries with different phosphine moieties. The synthesised ligands were characterised on solid support by conventional 31P NMR spectroscopy and, cleaved from the support, as their phosphine oxides by HPLC, 1H NMR, 31P NMR and high resolution ESMS. Palladium(II) allyl complexes were generated from the resin bound ligands and to demonstrate their catalytic properties, palladium catalysed asymmetric allylic substitution reactions were performed. Good yields and moderate enantioselectivity was obtained for the selected combination of catalysts and substrate, but most importantly the concept of this new methodology was proven. Screening of ligand libraries should afford more selective catalysts.
Supratentorial extraventricular ependymal neoplasms
Authors: Shuangshoti Shanop , Rushing Elisabeth J. , Mena Hernando , Olsen Cara , Sandberg Glenn D. 
Published: April 2005

AbstractBACKGROUNDPublished research on the clinicopathologic features of extraventricular ependymal neoplasms of the cerebral hemispheres has been scant.METHODSThirty‐two archival cases were studied to investigate the prognostic impact of clinicopathologic parameters including flow cytometry, the proliferation (Ki‐67) labeling index, and p53 expression.RESULTSAmong these 32 cases were 2 subependymomas, 19 ependymomas, and 11 anaplastic ependymomas. No significant gender predilection was observed, and 45% of patients were in their second or third decade of life. The left cerebral hemisphere was 1.5 times more commonly involved. On available imaging studies, lesions were often cystic, with or without a mural nodule. Tumors expressed glial fibrillary acidic protein (87%), S‐100 protein (77%), cytokeratin (43%), and epithelial membrane antigen (17%). Ki‐67 proliferation index paralleled tumor grade. Immunoreactivity for p53 protein was observed in the 2 cases of subependymoma, in 10 of 11 anaplastic ependymomas, and in 6 of 17 ependymomas. Flow cytometry performed in 27 tumors revealed diploidy in 20 cases and aneuploidy in 4 cases (3 anaplastic and 1 classic ependymomas), with S‐phase fraction ranging from 0.2–9.7. Eleven subjects were additionally treated with radiotherapy, and 3 with chemotherapy. Follow up was available in 25 (78%) patients.CONCLUSIONSThe results of the current study suggest that there is no significant relation between histopathology, Ki‐67 proliferation index, p53 immunolabeling, tumor ploidy, and biologic behavior. Cancer 2005. Published 2005 by the American Cancer Society.
Distribution and abundance of metabotropic glutamate receptor subtype 2 in rat brain revealed by [3H]LY354740 binding in vitro and quantitative radioautography: Correlation with the sites of synthesis, expression, and agonist stimulation of [35S]GTPγs binding
Authors: Richards Grayson , Messer Jürg , Malherbe Pari , Pink Richard , Brockhaus Manfred , Stadler Heinz , Wichmann Jürgen , Schaffhauser Hervé , Mutel Vincent 
Published: April 2005

AbstractUntil recently, there was a lack of selective radioligands for the subtypes of metabotropic glutamate (mGlu) receptors. [3H]LY354740 ((+)‐2‐aminobicyclo[3,1,0]hexane‐2,6‐dicarboxylic acid), a selective agonist for group II receptors (mGlu2 and ‐3, which are negatively coupled to cAMP production), has now been used to map their brain distribution and abundance by in vitro binding and quantitative radioautography. The selective cation dependence of its binding allowed the discrimination between mGlu2 and mGlu3 receptor labeling. Thus, in the presence of Ca2+ and Mg2+ ions, the agonist bound selectively to mGlu2 receptors as evidenced by: 1) the correlative distribution and abundance of binding sites (highest in the lacunosum moleculare of the hippocampus and lowest in white matter) with mGlu2 receptor mRNA and protein revealed by in situ hybridization histochemistry and immunohistochemistry, respectively; 2) its selective pharmacology; and 3) the distribution of LY354740‐stimulated [35S]GTPγS binding (25–97% above basal, according to the brain region), revealing G protein‐coupled receptor coupling to Gi proteins. Nonspecific binding (in the presence of 10 μM DCG‐IV, a group II‐selective, mGlu2‐preferring, receptor agonist) was <10% of total. In adjacent sections, the distribution of binding sites for [3H]DCG‐IV was very similar. This extensive study paves the way for investigations of the regional expression and regulation of mGlu2 receptors in human CNS diseases, such as Alzheimer's disease, which may reveal their functional roles and identify potential therapeutic drug targets. Indeed, it has recently been demonstrated (Higgins et al. [2004] Neuropharmacology 46:907–917) that pharmacological manipulation of mGlu2 receptors influences cognitive performance in the rodent. J. Comp. Neurol. 487:15–27, 2005. © 2005 Wiley‐Liss, Inc.
Photoactivatable green fluorescent protein as a single‐cell marker in living embryos
Authors: Stark Danny A. , Kulesa Paul M. 
Published: April 2005

AbstractSelective marking of a single cell within an embryo is often difficult to perform with existing methods. Here, we report a minimally invasive optical technique that uses 405‐nm laser light to photoactivate a variant of green fluorescent protein (PAGFP). Single cells and small groups of cells (n < 10) are successfully marked, from a region of cells injected and electroporated with PAGFP, in both whole chick embryo explants and in ovo. Photoactivated cells display normal cell migratory behaviors and retain a bright GFP signal for at least 24 hr when followed with confocal time‐lapse microscopy. We determined that using a low‐magnification objective (∼ ×10) and low laser power (∼1–10%) leads to a steady increase in fluorescence signal within a photoactivated cell and minimizes photobleaching. The utility of PAGFP photoactivation was tested to address a specific question in developmental biology. Specifically, we asked whether neighboring migratory cells that emerge from the hindbrain and invade surrounding peripheral tissues maintain neighbor relationships while traveling to the destination sites. We found that some neural crest do not maintain neighbor relationships, such that two neighboring cells near the neural tube cells may populate different branchial arches. The ability to optically photoactivate PAGFP in a single or small group of cells and follow individual cell migratory behaviors within a living embryo offers a powerful, minimally invasive cell marking tool for precise, in vivo cell migration studies. Developmental Dynamics 233:983–992, 2005. © 2005 Wiley‐Liss, Inc.
Conserved expression of a novel gene during gonadal development
Authors: Hudson Quanah J. , Smith Craig A. , Sinclair Andrew H. 
Published: April 2005

AbstractWe isolated the novel gene Gonad Expressed Transcript (GET) from a chicken embryonic gonad library enriched for differentially expressed male transcripts. Chicken GET encodes a predicted protein containing a Pfam‐B 30624 domain with homology to a putative orthologue in mammals. Chicken GET expression was confined to the developing urogenital system. It was first detected in the glomerulus of the mesonephros of both sexes from embryonic day (E) 2.5. At E4.5, expression switches to the gonad of both sexes and then localizes to the gonadal cortex. We isolated the putative mouse orthologue and examined expression in the mouse embryo. Gonadal expression was conserved. Ovarian expression localized to the cortex as in the chicks. However, in contrast to the chicken, testis expression localized to the cords. In the adult, GET is expressed in the ovary but not the testis of both the chicken and the mouse. Expression of GET in the müllerian duct, wolffian duct, metanephric kidney, and external genitalia, suggests that GET may play a wider role in the development of the urogenital system. Developmental Dynamics 233:1083–1090, 2005. © 2005 Wiley‐Liss, Inc.
Groucho corepressor proteins regulate otic vesicle outgrowth
Authors: Bajoghli Baubak , Aghaallaei Narges , Czerny Thomas 
Published: April 2005

AbstractThe Groucho/Tle family of corepressor proteins is known to regulate multiple developmental pathways. Applying the dominant‐negative effect of the short member Aes, we demonstrate here a critical role of this gene family also for ear development. Misexpression of Aes in medaka embryos resulted in reduced size or loss of otic vesicles, whereas overexpression of the full‐length Groucho protein Tle4 gave the opposite phenotype. These results are in close agreement with phenotypes observed for eye formation, suggesting a similar role for Groucho/Tle proteins in the developmental pathways of both sensory organs. Furthermore, by using the heat‐inducible HSE promoter, we observed reversible branching of the embryonic axis upon Aes misexpression, indicating a transient duplication of the organizer. Groucho proteins, therefore, are critical for organizer maintenance. Developmental Dynamics 233:760–771, 2005 © 2005 Wiley‐Liss, Inc.
Magnetic Anisotropy of New Layered Copper(II) Bromide Complexes of 1‐Substituted Tetrazoles
Authors: Shvedenkov Yurii , Bushuev Mark , Romanenko Galina , Lavrenova Ludmila , Ikorskii Vladimir , Gaponik Pavel , Larionov Stanislav 
Published: April 2005

AbstractTwo new isostructural complexes, dibromobis(1‐ethyltetrazole)copper(II) (1) and dibromobis(1‐hexyltetrazole)copper(II) (2), have been synthesised. Each bromine atom in the crystal structure of 1 and 2 is bonded to two copper atoms to give rise to a polymeric corrugated network. The polymeric layers are distinctly separated by tetrazole ligands. Both solids exhibit a phase transition to the ferromagnetic state with Curie temperatures of 8.5 K and 8.9 K for 1 and 2, respectively, and a strong anisotropy of the magnetic susceptibility below the ordering temperature. The easy magnetisation axis lies along the monoclinic axis, and the hard magnetisation axis is orthogonal to the polymeric layers. Effective anisotropy fields were estimated as (720–3020 Oe). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
New Layered Polymeric Metamagnet Based on Copper(II) Complex with3‐Imidazoline Nitroxide
Authors: Burdukov Alexei , Shvedenkov Yurii , Pervukhina Natalie , Reznikov Vladimir 
Published: April 2005

AbstractA new complex, bis[4‐(2‐oxido‐1‐butenyl)‐2,2,5,5‐tetramethylimidazolidine‐1‐oxyl]copper(II) (CuLEt2), has been synthesized. The synthesis, characterization, and magnetic properties as well as the crystal structure of CuLEt2 have been studied. The layered solid of the complex possesses a metamagnetic phase transition at 4.5 K and shows strong anisotropy of magnetic properties below the ordering temperature. The easy magnetization axis lies along the b axis. The hard magnetization axis is orthogonal to the polymeric layers. Effective anisotropy fields have been estimated (H⟂ = 1390 Oe, H∥ = 420 Oe). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Do Sodium Oxofluoroaluminates Exist at Room Temperature?
Authors: Kucharík Marián , Boča Miroslav , Bessada Catherine , Fuess Hartmut 
Published: April 2005

AbstractAlumina dissolution in cryolite melts is currently associated with the formation of oxofluorospecies. Mixtures of Na3AlF6 and Al2O3 were heated under different conditions of temperature, time and atmosphere. The existence of oxofluorospecies in solidified samples at room temperature was investigated by X‐ray diffraction, IR and Magic Angle Spinning NMR spectroscopy. The formation of β‐alumina (NaAl11O17) was detected depending on the heating conditions, but no oxofluoroaluminate species were found. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Kinetics of Cyclooctene Epoxidation with tert‐Butyl Hydroperoxide in the Presence of [MoO2X2L]‐Type Catalysts (L = Bidentate Lewis Base)
Authors: Al‐Ajlouni Ahmad , Valente Anabela A. , Nunes Carla D. , Pillinger Martyn , Santos Ana M. , Zhao Jin , Romão Carlos C. , Gonçalves Isabel S. , Kühn Fritz E. 
Published: April 2005

AbstractMoVI complexes with the general formula [MoO2X2L] [X = Cl, Br; L = 4,4'‐dimethyl‐2,2'‐bipyridine (dmbp) or 4‐hexyl‐4'‐methyl‐2,2'‐bipyridine (hmbp)] have been prepared and characterized by IR and solution NMR (1H, 13C, 17O and 95Mo) spectroscopy. The complexes were applied as catalysts in the homogeneous phase for the epoxidation of cyclooctene, with tert‐butyl hydroperoxide (TBHP) as the oxygen source. The desired epoxide was the only product and turnover frequencies of up to about 9000 h–1 could be reached. The catalytic activities increased in the order [MoO2Br2(dmbp)] < [MoO2Br2(hmbp)] < [MoO2Cl2(dmbp)] < [MoO2Cl2(hmbp)]. A kinetic model was built up for a homogeneous batch reactor based on a simplified mechanism involving three steps: (i) reversible coordination of TBHP to the starting MoVI complex to give a MoVI alkylperoxide; (ii) irreversible oxidation of cyclooctene to cyclooctene oxide by the species formed in step 1, with formation of the starting complex and tert‐butyl alcohol; (iii) reversible coordination of tert‐butyl alcohol to the starting complex. This model is consistent with the observed kinetics. The first step in this reaction mechanism was characterized in more detail by studying the kinetics of the reaction of the starting complexes with TBHP in the absence of any reductant by UV/Vis spectroscopy. Rate constants, equilibrium constants, and activation parameters were determined. All ΔS‡ values were negative and therefore support an associative mechanism in which a seven‐coordinate intermediate is formed. The results also suggest that the first step is not always the rate‐limiting step of cyclooctene epoxidation with these complexes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Two New μ‐(1,3‐Azido)‐Bridged Polymers: Alternating Single and Double Bridges in a 1D Nickel(II) Complex and Uniform Bridge in a 2D Copper(II) Complex: Syntheses, Single‐Crystal Structures and Magnetic Studies
Authors: Manna Subal Chandra , Konar Sanjit , Zangrando Ennio , Drew Michael G. B. , Ribas Joan , Ray Chaudhuri Nirmalendu 
Published: April 2005

AbstractTwo polymeric azido bridged complexes [Ni2L2(N3)3]n(ClO4)n (1) and [Cu(bpds)2(N3)]n(ClO4)n(H2O)2.5n (2) [L = Schiff base, obtained from the condensation of pyridine‐2‐aldehyde with N,N,2,2‐tetramethyl‐1,3‐propanediamine; bpds = 4,4'‐bipyridyl disulfide] have been synthesized and their crystal structures have been determined. Complex 1, C26H42ClN15Ni2O4, crystallizes in a triclinic system, space group P$\tilde {1}$ with a = 8.089(13), b = 9.392(14), c = 12.267(18) Å, α = 107.28(1), β = 95.95(1), γ = 96.92(1)° and Z = 2; complex 2, C20H21ClCuN7O6.5S4, crystallizes in an orthorhombic system, space group Pnna with a = 10.839(14), b = 13.208(17), c = 19.75(2) Å and Z = 4. The crystal structure of 1 consists of 1D polymers of nickel(L) units, alternatively connected by single and double bridging μ‐(1,3‐N3) ligand with isolated perchlorate anions. Variable temperature magnetic susceptibility data of the complex have been measured and the fitting of magnetic data was carried out applying the Borrás‐Almenar formula for such types of alternating one‐dimensional S = 1 systems, based on the Hamiltonian H = –JΣ(S2iS2i–1 + αS2iS2i+1). The best‐fit parameters obtained are J =–106.7  ± 2 cm–1; α = 0.82 ± 0.02; g = 2.21 ± 0.02. Complex 2 is a 2D network of 4,4 topology with the nodes occupied by the CuII ions, and the edges formed by single azide and double bpds connectors. The perchlorate anions are located between pairs of bpds. The magnetic data have been fitted considering the complex as a pseudo‐one‐dimensional system, with all copper(II) atoms linked by μ(1,3‐azido) bridging ligands at axial positions (long Cu···N3 distances) since the coupling through long bpds is almost nil. The best‐fit parameters obtained with this model are J = –1.21 ± 0.2 cm–1, g = 2.14 ± 0.02. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Nortricyclyl‐ and Norbornenyl‐Acylrhodium Complexes from the Reaction of Norbornadiene Rhodium(I) Complexes with o‐(Diphenylphosphanyl)benzaldehyde
Authors: El Mail Rachad , Garralda María Angeles , Hernández Ricardo , Ibarlucea Lourdes , Pinilla Elena , Torres María Rosario , Zarandona Malkoa 
Published: April 2005

Abstract[{Rh(Nbd)Cl}2] (Nbd = norbornadiene) reacts with o‐(diphenylphosphane)benzaldehyde in benzene solution to give the rhodium(III) complex [Rh(Cl)(C7H9){o‐PPh2(C6H4CO)}]n (1), where C7H9 is a nortricyclyl (Ntyl) group. Complex 1 reacts with various bidentate N‐donors, such as biacetyldihydrazone, 2,2'‐bipyridine, 8‐aminoquinoline, 2‐(aminomethyl)pyridine, or pyridine, to afford nortricyclyl [Rh(Cl){o‐PPh2(C6H4CO)}(Ntyl)(NN)] complexes. The presence of the nortricyclyl group and the structure of the complexes have been confirmed by NMR spectroscopy and, in one case, by single‐crystal X‐ray diffraction. Nortricyclyl complexes containing bidentate N‐donors are also formed by the reaction in benzene of PPh2(o‐C6H4CHO) with the corresponding [Rh(Cl)(Nbd)(NN)] compounds prepared “in situ”. [Rh(Cl)(Nbd)(bipy)] prepared “in situ” reacts with PPh2(o‐C6H4CHO) in methanol to give the complex [Rh(Cl){o‐PPh2(C6H4CO)}(C7H9)(bipy)], where C7H9 is a norbornenyl (Nbyl) group. This compound has been fully characterized by NMR spectroscopy. A proposal for the selective production of the norbornenyl and the nortricyclyl derivatives is presented. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)