bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study of the Balmer Spectrum of Hydrogen from a High‐Pressure Arc Discharge. II. Comparison of Experiment and Theory
Authors: Radtke R. , Günther K. , Spanke R. 
Published: July 2007

AbstractThe intensity distribution in the Balmer spectrum of hydrogen was calculated in the context of a model in which a cut‐off Coulomb potential is applied to simulate the influence of the surrounding plasma on the spectral distribution of atomic oscillator strengths. The results show satisfactory over‐all agreement with experimental data obtained from a high‐pressure are discharge.
Ein Differenzmeßverfahren zur sehr genauen Bestimmung der Güte und Resonanzfrequenz von Mikrowellenresonatoren durch Amplitudenmodulation des Meßsignals
Authors: Gundermann S. 
Published: July 2007

AbstractIn diesem Beitrag wird ein Differenzmeßverfahren angegeben, das eine sehr genaue Bestimmung der Resonanzfrequenz und Resonatorgüte auch von stark belasteten Mikrowellenresonatoren ermöglicht.
A Thermodynamics Approach to the Deflected Wall‐Stabilized Electric Arc Return Process
Authors: Ramos‐Barrado J. R. 
Published: July 2007

AbstractThe return of a deflected wall‐stabilized electric arc to the axial position is studied as a relaxation process within the framework of the after‐effects theory. The arc displacement is defined as an internal thermodynamics parameter and the determination of the affinity of this process was based on relaxation characteristic time.
Mode Transition of Ionization Waves in Non‐Uniform Magnetic Field
Authors: Maruyama T. , Ozawa T. , Mizuochi H. , Kitamura H. , Itagaki K. 
Published: July 2007

AbstractExperimental observations on mode transition in a positive column of Ne gas under non‐uniform axial magnetic field are reported. The self‐excited ionization wave is damped and a different type of ionization wave is grown in the region of the strong magnetic field near the magnetic coils. The mode transitions appear on both sides of the magnetic coils where the magnetic field crosses a critical value.
Possible High Power Laser Construction Using a New Discharge Type‐Heated Cathode Discharge in the Copper Vapours Continuously Evaporated from the Anode
Authors: Musa G. , Baltog A. , Popescu A. , Betiu N. , Mustata I. 
Published: July 2007

AbstractThe possibility to build a high power copper laser using a new type of discharge – heated cathode discharge in the copper vapours continuously evaporated from a melted spot on the anode surface is analysed.From the experimental data on this new discharge type, the equivalent pressure of the copper atoms in the discharge space has been obtained. This pressure can be as high as 1 torr. The density of the power in the discharge volume is evaluated to be more than 1 kW/cm3.
Targeted cell‐ablation in Xenopus embryos using the conditional, toxic viral protein M2(H37A)
Authors: Smith Stuart J. , Kotecha Surendra , Towers Norma , Mohun Timothy J. 
Published: July 2007

AbstractHarnessing toxic proteins to destroy selective cells in an embryo is an attractive method for exploring details of cell fate and cell–cell interdependency. However, no existing “suicide gene” system has proved suitable for aquatic vertebrates. We use the M2(H37A) toxic ion channel of the influenza‐A virus to induce cell‐ablations in Xenopus laevis. M2(H37A) RNA injected into blastomeres of early stage embryos causes death of their progeny by late‐blastula stages. Moreover, M2(H37A) toxicity can be controlled using the M2 inhibitor rimantadine. We have tested the ablation system using transgenesis to target M2(H37A) expression to selected cells in the embryo. Using the myocardial MLC2 promoter, M2(H37A)‐mediated cell death causes dramatic loss of cardiac structure and function by stage 39. With the LURP1 promoter, we induce cell‐ablations of macrophages. These experiments demonstrate the effectiveness of M2(H37A)‐ablation in Xenopus and its utility in monitoring the progression of developmental abnormalities during targeted cell death experiments. Developmental Dynamics 236:2159–2171, 2007. © 2007 Wiley‐Liss, Inc.
Cited1 and Cited2 are differentially expressed in the developing kidney but are not required for nephrogenesis
Authors: Boyle Scott , Shioda Toshi , Perantoni Alan O. , de Caestecker Mark 
Published: July 2007

AbstractEarly kidney development in mammals is characterized by reciprocal tissue interaction between the ureteric bud and the metanephric mesenchyme. The coordinated response to this interaction is regulated largely at the transcriptional level. Here, we investigate the expression and function of Cited1, a transcriptional cofactor that we have previously implicated in kidney development. We show that Cited1 is expressed in the metanephric mesenchyme after invasion of the ureteric bud and that its expression is limited to the cap mesenchyme, those cells that aggregate most tightly around the tip of the ureteric bud and give rise to nephronic epithelium of the adult kidney. Cited1 is down‐regulated during the initial stages of epithelial conversion and is not expressed past this progenitor stage. Despite its unique expression pattern, deletion of Cited1 does not disrupt kidney development. We hypothesized that this finding was due to functional redundancy with other members of this gene family. The expression pattern of Cited2 overlaps that of Cited1, but its deletion, either alone or in combination with Cited1, does not disrupt epithelial differentiation of the metanephric mesenchyme. From these studies, we conclude that Cited1 and 2 are dynamically expressed during kidney development, but are not required for nephrogenesis. Developmental Dynamics 236:2321–2330, 2007. © 2007 Wiley‐Liss, Inc.
The diabetogenic, insulin‐specific CD8 T cell response primed in the experimental autoimmune diabetes model in RIP‐B7.1 mice
Authors: Karges Wolfram , Rajasalu Tarvo , Spyrantis Andreas , Wieland Andreas , Boehm Bernhard , Schirmbeck Reinhold 
Published: July 2007

AbstractType 1 diabetes mellitus can result from the specific destruction of pancreatic beta cells by autoreactive T cells. As shown here, experimental autoimmune diabetes (EAD) is efficiently induced in RIP‐B7.1 mice by preproinsulin (ppins)‐encoding DNA vaccines. EAD develops in RIP‐B7.1 mice within 3–4 wk after a single immunization with ppins‐encoding plasmid DNA. RIP‐B7.1 mice develop insulitis, insulin deficiency and hyperglycemia after vaccination with plasmids encoding murine ppins‐I or murine ppins‐II or human hu‐ppins. EAD induction critically depends on CD8 T cells and is independent of CD4 T cells. To be diabetogenic, ppins‐specific CD8 T cells had to express IFN‐γ. Neither expression of perforin nor signaling through the type I IFN receptor is an essential component of this pathogenic CD8 T cell phenotype. Using plasmids encoding truncated ppins variants, we show that EAD is only induced by DNA vaccines encoding the insulin A‐chain. Diabetogenic CD8 T cells specifically recognize the Kb‐restricted A12–21 epitope of the insulin A‐chain. The RIP‐B7.1 model hence represents an attractive model for the characterization of cellular and molecular events involved in the CD8 T cell‐mediated immune pathogenesis of diabetes.
Alkyl Chain Length Defines 2D Architecture of Salophen Complexes on Liquid–Graphite Interface
Authors: Räisänen Minna T. , Mögele Florian , Feodorow Santeri , Rieger Bernhard , Ziener Ulrich , Leskelä Markku , Repo Timo 
Published: July 2007

AbstractA series of CuII, NiII and CoII salophen [salophen = N,N′‐(o‐phenylene)bis(salicylideneimine)] complexes were prepared, and their two‐dimensional (2D) assemblies on a liquid–graphite interface were studied by scanning tunnelling microscopy (STM). Depending on their varying alkyl chain lengths (C8, C10 or C12), two different new adlayers, parallelogram and honeycomb, were recorded. According to STM data, the driving force for these assemblies is a subtle interplay between a maximum amount of attractive van der Waals interaction of the alkyl chains and weak hydrogen bonding of the phenoxy moieties. Thus, the alkyl chain length defines the favoured 2D structure for each metal complex. As shown here, the self‐assembled monolayers of the salophen complexes studied provide an attractive approach to varying the surface architecture.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Photochemical Arylation Reactions by 4‐Chlorothioanisole
Authors: Lazzaroni Simone , Dondi Daniele , Fagnoni Maurizio , Albini Angelo 
Published: July 2007

AbstractThe photochemistry of 4‐chlorothioanisole (1) was investigated in various solvents, and it was found to involve the reduction to thioanisole as the main process. This occurs by heterolytic fragmentation of the triplet state of 1 and formation of the triplet 4‐thiomethoxyphenylium ion, as supported by DFT calculations. The cation is trapped by alkenes and, less efficiently, by benzene, resulting in new examples of the recently emerging arylation reactions by SN1 substitution of phenyl halides. The products from alkenes involve the phenonium ion as a further intermediate. The product distribution differs from the analogous reactions via 4‐methoxyphenylium for including a larger proportion of 4‐(β‐substituted alkyl)‐ rather than 4‐allylthioanisoles derivatives in alcohols, for the lower fraction of rearranged α‐substituted 4‐alkylthioanisoles and for the formation of some 4‐cyclopropylthioanisole with allyltrimethylsilane. The difference is accounted for by the more developed dipolar character of the C–C cyclopropane bonds in the intermediate phenonium, as indicated by DFT calculations.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
A New Conformationally Restricted Mimetic of Dipeptide EG – Synthesis of an Analogue of FEG
Authors: Galeazzi Roberta , Martelli Gianluca , Marcucci Eleonora , Mobbili Giovanna , Natali Desiré , Orena Mario , Rinaldi Samuele 
Published: July 2007

AbstractStarting from the chiral pyrrolidin‐2‐one 2, the carboxy group at C‐4 underwent homologation, and subsequent removal of the 1‐(4‐methoxyphenyl)ethyl group gave lactam 6. Alkylation of N‐1 with benzyl bromoacetate led to 7, a new conformationally restricted analogue of the dipeptide EG (Glu‐Gly). The usefulness of 7 was demonstrated by its eventual conversion into 8, an orthogonally protected analogue ofbioactive tripeptide FEG. In order to provide the biological activity of the new mimetic 9, available from 8 after the removal of the protecting groups, the conformational preference of 9 was ascertained by a detailed conformational analysis and a comparison with that of FEG (1). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Synthesis, Characterization and Electrochemical Polymerization of a Ru2+ Functionalized Pyrrole Monomer
Authors: Foster Kevin , McCormac Timothy 
Published: July 2007

AbstractA ruthenium(II) functionalized pyrrole, Ruthenium‐bis‐N,N′‐(2,2′‐bipyridyl)‐N‐(pyridine‐4‐ylmethyl‐(8‐pyrrole‐1‐yl‐octyl)amine)chloride, 1, has been synthesized and characterized by spectroscopic (UV/vis, 1H NMR) techniques and cyclic voltammetry. In solution 1 gave a redox couple associated with the Ru3+/2+ redox system and an irreversible wave associated with the oxidation of the covalently linked pyrrole moiety. What is believed to be homopolymerization, redox active surface films of 1 have been prepared by electrooxidation of the monomeric solution. The resulting polymeric film exhibited clear redox activity associated with the incorporated Ru2+ redox centre, which is covalently linked ruthenium centre to the pyrrole moiety in 1. The effect of surface coverage upon the electrochemical behavior of the deposited films has been undertaken. Preliminary investigations into the homogeneous charge transport dynamics of the polymeric film deposited onto platinum microelectrodes has been undertaken. Copolymerization with 3‐methylthiophene was carried out and a clear ruthenium response was seen. Films were formed by both cyclic voltammetry and chronocoulometry and studied. Various ratios were attempted but the ideal was found to be 52 : 5 mmol (3‐methylthiophene: 1).
Detection of Sulfur Microparticles in Bacterial Cultures by Flow Cytometry
Authors: Hübschmann T. , Vogt C. , Till S. , Rohwerder T. , Sand W. , Harms H. , Müller S. 
Published: July 2007

AbstractRepeated flow cytometric analyses of population shifts within a bacterial consortium growing under sulfate‐reducing conditions revealed unexpected and quick changes in forward scatter vs. side scatter dot plot patterns within less than 30 minutes of exposure to air. These pattern changes proceeded differently when cells were cultivated either at 30 °C or 12 °C. It was found that prominent sub‐distributions, clustering profoundly in size and number of events with time, represented sulfur particles and not microbial cells. Therefore, any interpretation of flow cytometric analyses of live bacteria grown under sulfate‐reducing conditions requires specific caution since sulfur particles might cause errors in data interpretation. To prevent artefacts, distinct treatments of the sample are recommended.
Analysis of an Anaerobic Chemostat Population Stably Dechlorinating 2,4,6‐Trichlorophenol
Authors: Breitenstein A. , Andreesen J. R. , Lechner U. 
Published: July 2007

Abstract2,4,6‐Trichlorophenol (2,4,6‐TCP) was extensively used in the past as a component of various pesticide formulations as well as a wood preservative and, therefore, is ubiquitously present in the environment. It is also formed during the disinfection of drinking water sources or during wastewater treatment and is frequently detected in sewage sludges. Under anaerobic conditions, reductive dehalogenation is the most promising biological process for its detoxification. Here, an anaerobic, 2,4,6‐TCP ortho‐dehalogenating mixed culture is described, which was originally enriched from a Saale river sediment. In order to be able to analyze the capacity of this dechlorination process for the removal of 2,4,6‐TCP, a steady‐state continuous culture was grown over a period of 270 days under an N2‐CO2 (80:20) gas atmosphere in a chemostat using formate as an electron donor and 2,4,6‐trichlorophenol (2,4,6‐TCP) as an electron acceptor. 2,4,6‐TCP was dechlorinated via 2,4‐dichlorophenol (2,4‐DCP) to 4‐chlorophenol (4‐CP) liberating two chlorine atoms per molecule of 2,4,6‐TCP as chloride. Per mol of chloride, 2.2 mol of formate were consumed and 0.17 mol of acetate formed. When yeast extract (0.01 %) was omitted from the cultivation medium, 2,4‐DCP accumulated in the chemostat, suggesting that the components in the yeast extract were essential for reductive dechlorination. A second fermentation was performed over a period of 130 days in the absence of CO2 in the gas atmosphere and of carbonate in the cultivation medium, resulting in a slightly higher specific dechlorination rate, a higher requirement for formate, and a lower protein yield, indicating that formate was used as a sole carbon source for growth. The dilution rate (D) was continuously increased, leading to an increase of the dechlorination velocity up to 400 μmol Cl–/L h, a maximum specific dechlorination rate of 0.48 μmol Cl–/L min (mg protein) and a yield of 5.1 g protein/(mol Cl– released). The microbial community structure of the mixed culture was investigated by amplified ribosomal DNA restriction analysis (ARDRA), sequencing, and hybridization with species specific oligonucleotide probes. The dechlorinating bacterium Desulfitobacterium hafniense was found to be a dominant member of the mixed chemostat culture. Further members of the chemostat culture were detected by comparative analysis of the restriction patterns and sequencing and identified as bacteria most closely related to strains of Sedimentibacter, Clostridium propionicum, and Pseudomonas aeruginosa.
The suitability of different FEA models for studying root fractures caused by wedge effect
Authors: Meira Josete B. C. , Quitero Mayra F. Z. , Braga Roberto R. , Placido Eliane , Rodrigues Flávia P. , Lima Raul G. , Ballester Rafael Y. 
Published: July 2007

AbstractFinite element analysis (FEA) utilizing models with different levels of complexity are found in the literature to study the tendency to vertical root fracture caused by post intrusion (“wedge effect”). The objective of this investigation was to verify if some simplifications used in bi‐dimensional FEA models are acceptable regarding the analysis of stresses caused by wedge effect. Three plane strain (PS) and two axisymmetric (Axi) models were studied. One PS model represented the apical third of the root entirely in dentin (PS‐nG). The other models included gutta‐percha in the apical third, and differed regarding dentin–post relationship: bonded (PS‐B and Axi‐B) or nonbonded (PS‐nB and Axi‐nB). Mesh discretization and material properties were similar for all cases. Maximum principal stress (σmax) was analyzed as a response to a 165 N longitudinal load. Stress magnitude and orientation varied widely (PS‐nG: 10.3 MPa; PS‐B: 0.8 MPa; PS‐nB: 10.4 MPa; Axi‐B: 0.2 MPa; Axi‐nB: 10.8 MPa). Axi‐nB was the only model where all σmax vectors at the apical third were perpendicular to the model plane. Therefore, it is adequate to demonstrate the tendency to vertical root fractures caused by wedge effect. Axi‐B showed only part of the σmax perpendicular to the model plane while PS models showed σmax on the model plane. In these models, σmax orientation did not represent a situation where vertical root fracture would occur due to wedge effect. Adhesion between post and dentin significantly reduced σmax. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
TiO2 nanotubes functionalized with regions of bone morphogenetic protein‐2 increases osteoblast adhesion
Authors: Balasundaram Ganesan , Yao Chang , Webster Thomas J. 
Published: July 2007

AbstractTitanium (Ti) and its alloys are widely used in orthopedic and dental applications. However, the native TiO2 layer is not bioactive enough to form a direct bond with bone, which sometimes translates into a lack of osseointegration into juxtaposed bone that might lead to long term implant failure. In this study, the 20 amino acid peptide sequence (the so‐called “knuckle epitope”) of bone morphogenetic protein‐2 (BMP‐2) was immobilized onto Ti nanotubes created by electrochemical anodization. Further, human osteoblast (bone‐forming cell) responses to such anodic Ti oxides functionalized with the BMP‐2 knuckle epitope was examined in vitro. Materials were characterized by scanning electron and atomic force microscopy. Results of this in vitro study continued to provide evidence of increased osteoblast adhesion on Ti anodized to possess nanotubes compared to unanodized Ti. However, for the first time, results also showed that the immobilization of the BMP‐2 knuckle epitope onto Ti anodized to possess nanotubes increased osteoblast adhesion compared to non‐functionalized anodized Ti, anodized Ti functionalized with amine (NH2) groups, and unanodized Ti after 4 h. Results also showed increased osteoblast adhesion on amine terminated anodized Ti compared to respective non‐functionalized anodized Ti and unanodized Ti. In summary, results of this in vitro study provided evidence that Ti anodized to possess nanotubes and then further functionalized with the BMP‐2 knuckle epitope should be further studied for improved orthopedic applications. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Contact guidance enhances the quality of a tissue engineered corneal stroma
Authors: Vrana E. , Builles N. , Hindie M. , Damour O. , Aydinli A. , Hasirci V. 
Published: July 2007

AbstractCorneal stroma is a very complex structure, composed of 200 lamellae of oriented collagen fibers. This highly complex nature of cornea is known to be important for its transparency and mechanical integrity. Thus, an artificial cornea design has to take into account this complex structure. In this study, behavior of human corneal keratocytes on collagen films patterned with parallel channels was investigated. Keratocytes proliferated well on films and reached confluency after 7 days in the incubation medium. Nearly all of the cells responded to the patterns and were aligned in contrast to the cells on unpatterned surfaces. Collagen type I and keratan sulfate secreted by keratocytes on patterned films appeared to be aligned in the direction of the patterns. The films showed an intermediate degradation over the course of a month. On the whole, transparency of the films increased with degradation and decreased by the presence of the cells. The decrease was, however, low and transparency level was maintained on the patterned films while on the unpatterned films a sharp decrease in transparency was followed by an improvement. This was due to the more organized distribution of cells and the oriented secretion of extracellular matrix molecules on patterned collagen films. Thus, these results suggest that application of contact guidance in cornea tissue engineering may facilitate the remodeling process, hence decrease the rehabilitation period. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Human macrophage response to UHMWPE, TiAlV, CoCr, and alumina particles: Analysis of multiple cytokines using protein arrays
Authors: Kaufman Adam M. , Alabre Claude I. , Rubash Harry E. , Shanbhag Arun S. 
Published: July 2007

AbstractAseptic loosening of total joint replacements is believed to be initiated by a macrophage response to prosthetic wear debris. To better characterize the early response to clinically relevant wear debris, we challenged primary human macrophages from four donors with ultra high molecular weight polyethylene (UHMWPE), TiAlV, CoCr, and alumina particles. After a 24‐h culture, protein arrays were used to quantify the secretion of 30 different cytokines and chemokines. Macrophages secreted detectable levels of nine mediators in culture: Interleukin‐1α (IL‐1α), tumor necrosis factor‐α (TNF‐α), IL‐1β, MCP‐1, IL‐8, IL‐6, GM‐CSF, IL‐10, and IL‐12p40. TiAlV particles were the most stimulatory, causing 5‐ to 900‐fold higher cytokine expression compared with nonstimulated cells and uniquely eliciting high levels of IL‐1α, IL‐6, IL‐10, and GM‐CSF. CoCr and alumina were mildly stimulatory and typically elicited two‐ to fivefold greater levels than nonstimulated cells. Surprisingly, UHMWPE did not elicit a significant increase in cytokine release. Our data suggests that IL‐1α, TNF‐α, IL‐1β, and MCP‐1 are the primary initiators of osteolysis and implicates metallic debris as an important trigger for their release. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Spectroscopic analysis of titanium surface functional groups under various surface modification and their behaviors in vitro and in vivo
Authors: Lu Xiong , Wang Yingbo , Yang Xiudong , Zhang Qiyi , Zhao Zhanfeng , Weng Lu‐Tao , Leng Yang 
Published: July 2007

AbstractIn the present study, surface functional groups of titanium surfaces gone through different treatments, including acid etched treatment (AE), nitric acid treatment (NT), heat treatment (HT), and alkali treatment (AT), and their behaviors in vitro and in vivo was thoroughly studied by spectroscopic analysis. In vitro and in vivo results revealed that the rank of bioactivity of various surfaces was AE < NT < HT < AT. XPS analysis indicated that AT greatly increased the OH group concentration on the titanium surface whereas HT reduced the OH group concentration. Thus, OH group difference could not be a good explanation of bioactivity difference. On the other hand, ToF‐SIMS analysis demonstrated the TiOH+/Ti+ ratios of various surfaces correlated well with the bioactivity and the surface energies, which implied that Ti–OH could play an important role in the bioactivity. This detail investigation of the relationship between surface functional groups and surface bioactivity could help us to broaden the knowledge about the mechanism of bioactivity and to design next generation bioactive materials. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008