bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electron Kinetics in the Cathode Region of a Glow Discharge and in Hollow Cathodes
Authors: Valentini H.‐B. 
Published: July 2007

AbstractOn the basis of an improved cascade model a multi‐group theory for studying the electron kinetics in the cathode region of a glow discharge and in hollow cathodes is developed. The secondary electrons newly created by ionization are taken into account. The electrons are divided in groups with respect to the interval where they were created or where they made an inelastic collision. The inelastic collisions and the forward scattering are assumed to dominate. The mean energies of two neighbouring groups are taken to be different by the ionization energy or by parts of it. For the flux densities of the various electron groups a set of ordinary first order differential equations and corresponding boundary conditions are obtained and solved for He. These formulae are valid for any electric potentials. The results relatively well agree with those of Monte Carlo simulations. The first Townsend ionization coefficient differs substantially from that resulting from the Townsend formula. The velocity distribution function spatially varies and contains several groups of fast electrons. Using the detour factor the angular scattering can be included in the calculations.
Comparative Studies of the Exchange‐Correlation Potential Formulas for Coulomb Systems
Authors: Stolzmann W. , Rösler M. 
Published: July 2007

AbstractThe exchange‐correlation part (xc) to the free energy is numerical evaluated in the RPA at arbitrary degree of degeneracy. The results are compared with numerical data of easy‐to‐use analytic fit‐formulas or Padé approximants of the xc‐term. All together results show very high accuracy at extremly high densities (rs ≈ 1). The agreements disappear between the several formulas for increasing Brueckner parameter rs. Numerical results for the xc‐potentials (pressure and chemical potential) at finite temperatures for an electron‐ion system are given. The xc‐part of the ground state energy of our electron‐ion model is compared with the ground state energy for metallic hydrogen and with Monte‐Carlo calculations.
Partial Cross Sections for Dissoziative Ionization of Fluorinated Compounds by Electron Impact
Authors: Poll H. U. , Meichsner J. 
Published: July 2007

AbstractIonization cross sections of fragment ions of CF4, C2F6, C3F8, n‐C4F10, C2F4, 1‐C4F8, SiF4, COF2. CHF3 were determined in dependence on electron energy up to 125 eV by means of a quadrupol mass spectrometer. Tails at the low energy part of the characteristics are interpreted as a result of kinetic energy depending on molecular weight of fragments. Parent ions are only detected for chemically unsaturated compounds showing characteristic curves of ionization efficiency. Total cross sections obey the additive rule.
Muscle development in a biphasic animal: The frog
Authors: Elinson Richard P. 
Published: July 2007

AbstractKnowledge of muscle development in a vertebrate reflects strengths of the particular model system. For example, the origin of mesoderm is very well characterized in Xenopus laevis, where development of somites is less well understood. The major problem in muscle development, presented by frogs, is the complete replacement of larval muscles by adult muscles at thyroid hormone–dependent metamorphosis. All tail muscles die, all leg muscles form de novo, and muscles in the jaw and trunk show both processes. The nature of adult muscle progenitors remains unclear. Comparison of X. laevis development with divergent amphibian patterns, such as direct developers, which lack the larval tadpole, should highlight important steps in adult muscle formation. Developmental Dynamics 236:2444–2453, 2007. © 2007 Wiley‐Liss, Inc.
Robust CD4+ and CD8+ T cell responses to SIV using mRNA‐transfected DC expressing autologous viral Ag
Authors: Melhem Nada M. , Liu Xiang Dong , Boczkowski David , Gilboa Eli , Barratt‐Boyes Simon M. 
Published: July 2007

AbstractA potentially powerful strategy for therapeutic HIV vaccination is the use of DC transfected with mRNA encoding autologous viral Ag, as epitopes presented by transfected DC would exactly reflect those expressed by infected cells in the individual. Using human and rhesus macaque monocyte‐derived DC, we show that nucleofection is a superior method for mRNA transfection, resulting in high‐level protein expression and DC maturation. DC transfected with SIV gag isolated from an infected monkey stimulated robust Ag‐specific recall T cell responses of similar magnitude to those induced by peptide‐pulsed PBMC that were predominantly CD8+ T cell mediated. Enhanced CD4+ T cell responses were stimulated when Gag was redirected into the lysosomal pathway via the targeting signal derived from lysosome‐associated membrane protein‐1 (LAMP‐1). Rhesus DC transfected with lysosome‐targeted gag encoding an escape mutation in an immunodominant CTL epitope stimulated CD4+ and CD8+ T cell responses of almost equivalent magnitude directed towards undefined epitopes outside of the mutated region. Finally, gag‐transfected DC from SIV‐infected monkeys stimulated significant Ag‐specific recall T cell responses in an entirely autologous system. These findings demonstrate that mRNA‐transfected DC expressing SIV Ag derived from infected monkeys stimulate broad and relevant T cell responses, supporting this approach for therapeutic HIV vaccine development.
MGL‐mediated internalization and antigen presentation by dendritic cells: A role for tyrosine‐5
Authors: van Vliet Sandra J. , Aarnoudse Corlien A. , Broks‐van den Berg Venice C. M. , Boks Martine , Geijtenbeek Teunis B. H. , van Kooyk Yvette 
Published: July 2007

AbstractProfessional antigen‐presenting cells are essential for the initiation of adaptive immune responses; however, they also play a vital role in the maintenance of tolerance towards self‐antigens. C‐type lectins can function as antigen receptors by capturing carbohydrate ligands for processing and presentation. Here, we focused on the dendritic cell (DC)‐expressed macrophage galactose‐type lectin (MGL), a C‐type lectin with a unique specificity for terminal GalNAc residues, such as the tumor‐associated Tn antigen. Soluble model antigens are efficiently internalized by MGL and subsequently presented to responder CD4+ T cells. The tyrosine‐5 residue in the YENF motif, present in the MGL cytoplasmic domain, was essential for the MGL‐mediated endocytosis in CHO cells. In conclusion, MGL contributes to the antigen processing and presentation capacities of DC and may provide a suitable target for the initiation of anti‐tumor immune responses.
Acetate inhibits NFAT activation in T cells via importin β1 interference
Authors: Ishiguro Kazuhiro , Ando Takafumi , Maeda Osamu , Ohmiya Naoki , Niwa Yasumasa , Goto Hidemi 
Published: July 2007

AbstractAcetate is a principal short chain fatty acid produced by bacterial fermentation in the colon and a major end product of alcohol metabolism. In the present study, we assessed the effects of acetate on T cell activation and found that acetate inhibited NFAT activation but not NF‐κB activation. Moreover, acetate impaired the nuclear translocation of NFAT but not that of NF‐κB. Unlike cyclosporin A (CsA), acetate did not affect the dephosphorylation of NFAT and calcineurin activity. Acetate impaired the binding of NFAT to importin β1, which is involved in NFAT nuclear translocation. NFAT is a critical transcription factor in cytokine and early response gene expression in activated T cells. Agents targeting NFAT such as CsA are used to suppress harmful immune responses in inflammatory diseases. Therefore, we also evaluated the efficacy of acetate in murine models of inflammatory diseases, and found that acetate administration (as well as administration of dexamethasone) attenuated trinitrobenzenesulfonic acid‐induced colitis and dinitrofluorobenzene‐induced dermatitis. These findings indicate for the first time that acetate inhibits NFAT activation by interfering with the interaction between NFAT and importin β1 in T cells and that acetate can potentially act as an anti‐inflammatory agent.
(Arene)ruthenium(II) Complexes Containing Substituted Bis(pyrazolyl)methane Ligands – Catalytic Behaviour in Transfer Hydrogenation of Ketones
Authors: Carrión M. Carmen , Jalón Félix A. , Manzano Blanca R. , Rodríguez Ana M. , Sepúlveda Francisco , Maestro Miguel 
Published: July 2007

AbstractA new and safer methodology has been developed for the synthesis of bis(pyrazol‐1‐yl)methane ligands (NN). Several ligands containing different phenyl groups on the central carbon atom have been obtained. Ruthenium derivatives of the type [Ru(arene)Cl(NN)]BPh4 (arene = benzene, p‐cymene) have been synthesised using these ligands. One or two isomers that differ regarding the axial or equatorial disposition of the phenyl group on the metallacycle have been obtained. Their formation is rationalised by considering steric effects. The structures of five derivatives were determined by X‐ray diffraction. In four complexes the phenyl substituent is in the axial disposition of the metallacycle and in one case in the equatorial orientation. The dihedral angle formed by the planes of the two pyrazole rings is always bigger for the complexes containing unsubstituted pyrazolyl heterocycles. The behaviour of the new derivatives in the transfer hydrogenation of benzophenone in the presence of KOH was studied. The benzene derivatives showed higher activity than the p‐cymene complexes. A marked and positive effect of the methyl groups on the pyrazolyl rings was observed. The effect of the substituents on the benzyl carbon atom was also important. It has been observed that the benzophenone hydrogenation was possible without the addition of complexes. The effect of the KOH concentration was evaluated and a concentration that leads to negligible conversion in a base‐only process was chosen. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Controlled Chemical Reduction of Uranyl Salts into UX4(MeCN)4 (X = Cl, Br, I) with Me3SiX Reagents
Authors: Berthet Jean‐Claude , Siffredi Gérald , Thuéry Pierre , Ephritikhine Michel 
Published: July 2007

AbstractUO2I2(thf)3 or UO2(OTf)2 are easily reduced by Me3SiX (X = Cl, Br, I) in acetonitrile into the tetravalent UX4(MeCN)4 complexes, which are useful precursors in uranium chemistry. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Kinetics and Magnetism of Phosphane Diadducts of Diruthenium(II,III) Tetraacetate
Authors: Burchell Tara J. , Cameron T. Stanley , Macartney Donal H. , Thompson Laurence K. , Aquino Manuel A. S. 
Published: July 2007

AbstractThe kinetic parameters for the axial‐ligand‐substitution reactions of [Ru2(μ‐O2CCH3)4(MeCN)2]+ in acetonitrile (MeCN) with PCy3 and PCy2Ph (Cy = cyclohexyl and Ph = phenyl) were investigated under pseudo first‐order conditions of excess phosphane. The rate‐determining formation of [Ru2(μ‐O2CCH3)4(MeCN)(PCy2R]+ appears independent of the nature of the incoming phosphane with an average k1 (25.0 °C) = (1.25 ± 0.06) × 103 M–1 s–1. A dissociatively activated mechanism is proposed for substitution of the axially coordinated acetonitrile, and the rate parameters are compared to earlier measurements carried out on [Rh2(μ‐O2CCH3)4(MeCN)2]. Variable‐temperature magnetic susceptibility measurements were carried out on the two phosphane diadducts, [Ru2(μ‐O2CCH3)4(PCy3)2]PF6, (1) and [Ru2(μ‐O2CCH3)4(PCy2Ph)2]PF6 (2), and showed behaviour unique to a Boltzmann distribution of states over the temperature range 2–300 K. To support the magnetic measurements, the single‐crystal X‐ray structure of 1 was redetermined at various temperatures down to –150 °C and showed a distinct decrease in the Ru–Ru bond length with decreasing temperature, consistent with a σ2π4δ2π*3 configuration at low temperature (ground state) and a σ2π4δ2π*2δ*1 configuration at room temp. In addition, the structure redeterminations of 1 were better resolved than the earlier reported structure and also corrected a minor error in that the molecule of solvation was found to be 1,2‐dichloroethane instead of dichloromethane. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Exploration of meso‐Substituted Formylporphyrins and Their Grignard and Wittig Reactions
Authors: Dahms Katja , Senge Mathias O. , Bakar M. Bakri 
Published: July 2007

AbstractFormylporphyrins were prepared by using either the 1,3‐dithian‐2‐yl residue as a precursor for the CHO group or by the Vilsmeier reaction. Two synthetic routes for the introduction of the 1,2‐dithian‐2‐yl group were explored. Furthermore, reactions of the 1,3,5‐trithian‐2‐yl group with porphyrins were examined as well as spirobisdithiane derivatives as precursors for the ultimate assembly of porphyrin spirobisdithanyl‐linked bioconjugates. The obtained formylporphyrins were reacted with organomagnesium or organophosphorus compounds. A series of hydroxyporphyrins resulting from the Grignard reaction of 5,15‐substituted porphyrins were synthesised in high yields. Several porphyrins with unsaturated residues introduced by the Wittig reaction were obtained in moderate yields. The less sterically hindered 5,15‐substituted porphyrins show increased reactivity and give higher yields; their reaction products are higher in stability relative to other porphyrin systems.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Activity and Reaction Mechanism of the Initial Enzymatic Step Specifying the Microbial Degradation of 2,4‐Dichlorophenoxyacetate
Authors: Müller R. H. 
Published: July 2007

AbstractThe capability of Delftia acidovorans MC1010 (SdpA+, RdpA–) to degrade the herbicides 2,4‐dichlorophenoxyacetate (2,4‐D) and 4‐chloro‐2‐methylphenoxyacetate (MCPA) was investigated in batch degradation experiments and interpreted in the light of the catalytic activity of the initial enzyme SdpA, an α‐ketoglutarate‐dependent dioxygenase, catalyzing the cleavage of the ether bond. Dense inocula of this strain degraded high initial 2,4‐D concentrations quickly to below the detection limit. The specific degradation rate became slower and the degradation remained incomplete when low initial biomass concentrations and/or 2,4‐D concentrations were used. With low initial 2,4‐D concentrations, the degradation rate became nearly concentration‐independent. This effect was less pronounced with MCPA, a substrate that is more readily degraded by SdpA than 2,4‐D. (S)‐2‐(2,4‐dichlorophenoxy)propionate ((S)‐2,4‐DP), the favored substrate of SdpA used as comparison, was almost completely utilized under the various conditions. The observed differences were attributed to the easier regeneration of the essential co‐substrate α‐ketoglutarate with MCPA and above all (S)‐2,4‐DP as a substrate compared to 2,4‐D. Decreasing SdpA activity, which was observed during the starvation of MC1010, will contribute to the apparent recalcitrance of 2,4‐D. Degradation of 2,4‐D by Bradyrhizobium sp. RD5‐C2, a strain initiating 2,4‐D cleavage by a monooxygenase not requiring an organic intermediate as a co‐substrate, proceeded to completion despite the approximately 20‐fold lower degradation rates compared to those obtained with strain MC1010. However, lowering of biomass concentrations resulted in restricted degradation also with strain RD5‐C2. The results were discussed in terms of the kind of co‐substrate in the cleavage reaction, the availability of essential intracellular metabolites, and the cells' maintenance demands.
Development of a Pilot Plant Facility for the Conversion of Renewables in Biotechnological Processes
Authors: Venus J. , Richter K. 
Published: July 2007

AbstractThe experience of recent years has shown that a swift transfer of new biotechnological processes into practice often fails due to the lack of a reference facility that can be used for multiple applications. Besides the basic research there is a need for investigations at different scales from the laboratory to the industrial scale. The construction of a pilot plant facility for the production of lactic acid at the Leibniz Institute for Agricultural Engineering Potsdam‐Bornim (ATB) consequently fills a gap in the various phases of bioprocess engineering from applied fundamental via application research to the launch of biotechnological processes in practice. An example of a biorefinery is presented, which produces 10 t lactic acid in 200 days per year. The steps of project development from the idea and concept up to the planning and installation of the plant are described. First results for the manufacture of lactic acid from rye wholemeal illustrate the conformity with existing investigations. Further research may lead to an increase in the long‐term stability of the fermentation and to an adaptation of the process to the demands of product quality. The availability of product samples should familiarize interested partners in industry with the specific product requirements and win them as cooperation partners for research projects.
A Halophilic and Osmotolerant Azospirillum brasilense Strain from Algerian Soil Restores Wheat Growth under Saline Conditions
Authors: Nabti E. , Sahnoune M. , Adjrad S. , Van Dommelen A. , Ghoul M. , Schmid M. , Hartmann A. 
Published: July 2007

AbstractA new bacterial isolate (NH) from salt‐affected soil was identified as Azospirillum brasilense using phenotypic analyses and 16S rDNA‐based phylogeny. This isolate showed resistance towards 3,4‐dehydroproline and optimal growth at 200 mmol/L NaCl, tolerating salt stress of 300 mmol/L NaCl in the absence of osmoprotectants and up to 600 mmol/L NaCl in the presence of glycine betaine and Ulva lactuca extracts. This effect was enhanced with extracts of the marine algae Ulva lactuca. A. brasilense strain NH can produce auxin indole acetic acid under saline conditions. The hypothesis was tested that the inoculation of this osmotolerant rhizosphere strain could improve the growth of wheat under saline stress conditions. Normal wheat growth was restored in the presence of both 150 mmol/L and 200 mmol/L NaCl after inoculation with A. brasilense NH. Under saline conditions, its effect of promoting plant growth of wheat was significantly superior to that of A. brasilense Sp7, the non‐halotolerant type strain. A. brasilense NH restored wheat growth at elevated salt concentrations in pot and field experiments even better in the presence of osmoprotective Ulva lactuca extracts.
Dynamics of Benzene and Toluene Degradation in Pseudomonas putida F1 in the Presence of the Alternative Substrate Succinate
Authors: Rüegg I. , Hafner T. , Bucheli‐Witschel M. , Egli T. 
Published: July 2007

AbstractIn batch and continuous culture, the regulation of benzene and toluene degradation by Pseudomonas putida F1 was investigated in the presence of the alternative carbon and energy source succinate. In batch culture, benzene and toluene were used simultaneously, whereas succinate suppressed benzene consumption under carbon excess conditions resulting in diauxic growth. In carbon‐limited continuous culture mixed substrate growth was observed. Since in nature low substrate concentrations and ever changing conditions prevail, this paper focuses on the dynamics of benzene/toluene degradation, biomass synthesis, and the regulation of benzene/toluene‐degrading enzymes in cultures growing continuously at a dilution rate of 0.1 h–1, when shifting the supply of the carbon and energy source from succinate to various mixtures of succinate and benzene/toluene, or to benzene only. When the succinate concentration was kept constant (1.25 mM) and the medium was supplemented with benzene (2 mM), growth with benzene began already two hours after the shift. In contrast, replacing succinate with benzene only led to a wash out of biomass for more then ten hours, before biomass production from benzene started. A striking and reproducible transition pattern was observed for all shifts where the succinate concentration was reduced or succinate was omitted. After an initial period of biomass production from benzene, the culture collapsed and a wash‐out of biomass was observed. However, this wash‐out was not accompanied by an increase in benzene in the cultivation liquid, indicating a benzene uptake without conversion into biomass. Another possibility is that in phases of low biomass concentrations, cells were only able to use the low amounts of benzene/toluene dissolved in the cultivation liquid yielding low biomass concentrations whereas in phases of high biomass concentrations, they were able to rapidly utilize the aromatic solvents so that additional benzene from the gas phase diffused into the cultivation liquid resulting in more biomass production. In most cases, growth resumed again after 10 to 80 h. Currently, the reasons for the decrease in biomass after the first rise are unknown. However, several indications rule out intoxication of the cells by either the solvents benzene or toluene themselves, or by toxic degradation intermediates, or by‐products.
Parosteal osteosarcoma: Case report and review of the literature
Authors: Hewitt Kim M. , Ellis Gary , Wiggins Richard , Bentz Brandon G. 
Published: July 2007

AbstractBackground.The majority of osteosarcoma cases of the head and neck are high‐grade lesions. We present a case and discuss the diagnostic and therapeutic implications of a rare low‐grade parosteal osteosarcoma of the maxilla.Methods.A 32‐year‐old man presenting to the Head and Neck Surgical Oncology clinic with a 1‐year history of a firm palatal mass. Evaluation clinically and radiographically raised the suspicion of an osteosarcoma.Results.A partial maxillectomy revealed a parosteal osteosarcoma with negative margins. No adjuvant therapy was recommended, and the patient remains without evidence of local recurrence after 3 years.Conclusions.Parosteal osteosarcomas of the head and neck region are rare, low‐grade variants of osteosarcoma, but have the potential to recur with simple local excision. Clinical and radiographic features are diagnostically helpful. Definitive diagnosis comes from histopathology, and wide local resection should be employed as the optimal treatment. © 2007 Wiley Periodicals, Inc. Head Neck, 2008
Results of a pilot study of the effects of celecoxib on cancer cachexia in patients with cancer of the head, neck, and gastrointestinal tract
Authors: Lai Victor , George Jonathan , Richey Luther , Kim Hong J. , Cannon Trinitia , Shores Carol , Couch Marion 
Published: July 2007

AbstractBackground.Animal models suggest that cyclooxygenase‐2 (COX‐2) inhibitors may be beneficial in suppressing cancer cachexia. We investigated the effect of short‐course celecoxib on body composition, inflammation, and quality of life (QOL) in patients with cancer cachexia in a phase II clinical pilot trial.Methods.Eleven cachectic patients with head and neck or gastrointestinal cancer were randomly assigned to receive placebo or celecoxib for 21 days while awaiting the initiation of cancer therapy. Body composition, resting energy expenditure, QOL, physical function, and inflammatory markers were measured on days 1 and 21.Results.Patients receiving celecoxib experienced statistically significant increases in weight and body mass index (BMI), while patients receiving placebo experienced weight loss and a decline in BMI. Patients receiving celecoxib also had increases in QOL scores.Conclusions.Cachectic patients receiving celecoxib gained weight, experienced increased BMI, and demonstrated improved QOL scores. Compliance was good and no adverse events were seen. © 2007 Wiley Periodicals, Inc. Head Neck, 2008