bluuebunny/crossref_metadata_2025_split huggingface dataset:
PP‐based nanocomposites with various intercalant types and intercalant coverages
Authors: Li Jianming , Ton‐That Minh‐Tan , Tsai Shih‐Jung 
Published: July 2006

AbstractIn this article, nanocomposites based on polypropylene containing montmorillonite, modified with two different intercalants (primary and quaternary amine), at three different coverage levels have been investigated. The specimens were prepared in a mini‐extruder machine with a counter‐rotating configuration. The effectiveness of intercalant type and clay coverage level on the dispersion was analyzed by different means, including X‐ray diffraction analysis, field emission gun scanning electron microscopy, transmission electron microscopy, and differential scanning calorimetry. The flexural performance of the specimens was also examined. POLYM. ENG. SCI. 46:1060–1068, 2006. © 2006 Society of Plastics Engineers
Two representations of the simple model and its application to 4f–5d excitation spectra of Dy3+ dopants in crystals
Authors: Xia S. D. , Duan C. K. 
Published: July 2006

AbstractThe 4f–5d excitation spectra of Dy3+ dopants in crystal YPO4 (in CaF2, LiYF4 as well) reported by van Pieterson et al. [Phys. Rev. B 65, 045114 (2002)] are studied theoretically using both the original and extended simple models without or with the non‐diagonal matrix elements taken into account. When the non‐diagonal matrix elements are taken into account, the same energy levels are obtained in both cases as expected and successfully interpret the 4f–5d spectra. When the non‐diagonal matrix elements are neglected, as in actual applications of the simple models, the results of the original simple model is much closer to the complete‐calculated ones than those of the extended simple model for ion Dy3+. This means the original simple model is more suitable for ion Dy3+. The effect of J ‐mixing of final states on the line strength of transitions due to f‐electron crystal field, which was ignored previously, is also discussed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Realistic investigations of correlated electron systems with LDA + DMFT
Authors: Held K. , Nekrasov I. A. , Keller G. , Eyert V. , Blümer N. , McMahan A. K. , Scalettar R. T. , Pruschke Th. , Anisimov V. I. , Vollhardt D. 
Published: July 2006

AbstractConventional band structure calculations in the local density approximation (LDA) [1–3] are highly successful for many materials, but miss important aspects of the physics and energetics of strongly correlated electron systems, such as transition metal oxides and f‐electron systems displaying, e.g., Mott insulating and heavy quasiparticle behavior. In this respect, the LDA + DMFT approach which merges LDA with a modern many‐body approach, the dynamical mean‐field theory (DMFT), has proved to be a breakthrough for the realistic modeling of correlated materials. Depending on the strength of the electronic correlation, a LDA + DMFT calculation yields the weakly correlated LDA results, a strongly correlated metal, or a Mott insulator. In this paper, the basic ideas and the set‐up of the LDA + DMFT(X) approach, where X is the method used to solve the DMFT equations, are discussed. Results obtained with X = QMC (quantum Monte Carlo) and X = NCA (non‐crossing approximation) are presented and compared, showing that the method X matters quantitatively. We also discuss LDA + DMFT results for two prime examples of correlated materials, i.e., V2O3 and Ce which undergo a Mott–Hubbard metal–insulator and volume collapse transition, respectively. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Pressure induced high spin to low spin transition in magnesiowüstite
Authors: Tsuchiya Taku , Wentzcovitch Renata M. , da Silva Cesar R. S. , de Gironcoli Stefano , Tsuchiya Jun 
Published: July 2006

AbstractUsing a rotationally invariant formulation of LDA + U, we report a successful study of the high spin (HS)/low spin (LS) transition in low solute concentration magnesiowüstite (Mw), (Mg1–x Fex )O, (x < 20%), the second most abundant phase in Earth's lower mantle. The HS state crosses over smoothly to the LS state passing through an insulating mixed spins state where properties change continuously, as seen experimentally. These encouraging results indicate this method should enable first principles studies of strongly correlated iron‐bearing minerals, a major class of mineral physics problems. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Expression of TPK1 and TPK2 genes encoding PKA catalytic subunits during growth and morphogenesis in Candida albicans
Authors: Souto Guadalupe , Giacometti Romina , Silberstein Susana , Giasson Luc , Cantore María Leonor , Passeron Susana 
Published: July 2006

AbstractThe transcript levels of Candida albicans TPK1 and TPK2 genes, encoding PKA catalytic subunits, as well as phosphotransferase activity, were measured in the parental strain CAI4 and in homozygous tpk1Δ and tpk2Δ mutants during vegetative growth and during yeast‐to‐mycelial transition in N‐acetylglucosamine liquid inducing medium at 37 °C. We observed two TPK2 transcripts, a major one of 1.8 kb and a minor one of 1.4 kb, and established by 3′‐RACE that they originate from the recognition of the three polyadenylation signals present in the 3′ untranslated region of the gene. During vegetative growth of CAI4 strain, the expression profiles of TPK1 and TPK2 varied similarly, reaching maximal expression at the late logarithmic phase. TPK1 mRNA levels were lower than those of TPK2 at all stages measured. In the corresponding homozygous tpk mutants, mRNA levels and the expression patterns of TPK1 and TPK2 were similar to those of CAI4, suggesting that the loss of one catalytic isoform is not compensated by overexpression of the other. Changes in PKA specific activity roughly correlated with fluctuations of mRNA expression levels. During yeast‐to‐mycelial transition, a sharp increase in TPK1 mRNA levels and in PKA‐specific activity correlated with the onset of germ‐tube formation in strain tpk2Δ. We also showed that tpk1Δ strain exhibited a delayed morphogenetic shift in comparison with CAI4 and tpk2Δ strains in several liquid inducing media, reinforcing the idea that Tpk1p is important for faster germ‐tube appearance. Copyright © 2006 John Wiley & Sons, Ltd.
Recurrent infections and immunological dysfunction in congenital disorder of glycosylation Ia (CDG Ia)
Authors: Blank C. , Smith L. A. , Hammer D. A. , Fehrenbach M. , DeLisser H. M. , Perez E. , Sullivan K. E. 
Published: July 2006

SummaryCongenital disorder of glycosylation Ia is the most common defect of glycosylation and is due to mutations in phosphomannomutase 2. This leads to aberrant N‐linked oligosaccharides. The phenotype of CDG Ia reflects the essential nature of glycosylation and patients typically present with multiple organs affected, with hypotonia, developmental delay, inverted nipples and abnormal fat pads. Later features include retinitis pigmentosa, stroke, cerebellar atrophy and malabsorption. Approximately 20% of patients die in the first year of life and infection is the most common cause of death. Immunological function has not previously been investigated in these patients and the critical role of oligosaccharides on adhesion molecules suggested that haematopoietic cell migration and communication could be disrupted by mutations in phosphomannomutase 2. We characterized the clinical features, performed standard immunological evaluations, and performed specific analyses of neutrophil adhesion molecules on two patients to address this question. Patient neutrophils had diminished chemotaxis but expressed comparable levels of adhesion molecules and rolled on artificial endothelium equivalently to control neutrophils. The most significant feature of the patients’ immunological function was poor vaccine responses. These two affected patients were begun on intravenous immunoglobulin with some improvement in their infections.
Factors Affecting the Strength of Flexor Tendon Repair
Authors: BHATIA D. , TANNER K. E. , BONFIELD W. , CITRON N. D. 
Published: July 2006

The effects of different thicknesses and configurations of core sutures were studied in human cadaveric flexor tendon repairs. Both straight and cyclic load tests were employed. To exploit the full strength of 4/0 suture material, the Kessler repair using four locked single knots would seem to be appropriate.
An Evaluation of the Risk of Cerebrospinal Fluid Leakage as a Function of the Surgical Approach to the Cochlear Nerve
Authors: Miller Brian Thomas , Hillman Todd 
Published: July 2006

AbstractObjective: Direct implantation into the cochlear nerve can bypass the potential limitations of conventional cochlear implants. Implantable electrical arrays increase the number of stimulation sites, broaden frequency selectivity, require less activating current, and are not dependent on cochlear anatomy. Cochlear nerve implantation demands a unique surgical exposure to the modiolus. This study comprises an assessment of the risk of generating an intraoperative cerebrospinal fluid (CSF) leak using this approach.Methods: Five fresh cadavers were obtained for dissection. Using dyed normal saline as an indicator, the central nervous system was pressurized to physiological parameters. Surgical approaches to the cochlear nerve were initiated. Leakage of indicator fluid for each approach was quantitatively and qualitatively assessed. Indicator dye in the surgical field was considered a CSF breech. Indicator fluid was collected and quantified.Results: Eighty percent of the surgical approaches caused quantifiable leaks with rates ranging from 0.1 mL/minute to 6 mL/minute. For directly implanted microarrays, the utilization of a modified facial recess approach with cochleostomy and modiolar drillout carries significant risk for generating a CSF leak during the procedure.
Nasopharyngeal Pleomorphic Adenoma in the Adult
Authors: Lee Scott L. , Lee C Y. , Silver Steven M. , Kuhar Siobhan 
Published: July 2006

AbstractIntroduction: Salivary gland tumors account for less than 5% of all neoplasms in the head and neck, with pleomorphic adenoma being the most common type. These typically arise in the palate, but we report a rare case of nasopharyngeal pleomorphic adenoma in an adult.Materials and Methods: The authors conducted a case report and literature review.Results: The patient presented with unilateral otalgia, tinnitus, and aural fullness. Nasal endoscopy revealed a pedunculated mass adjacent to the left torus tubarius and he was treated with an excisional biopsy. Histologic evaluation demonstrated pleomorphic adenoma.Discussion: Pleomorphic adenomas seldom present as nasopharyngeal masses and have a nonspecific appearance on endoscopy. Microscopic examination has characteristic features to aid in an accurate diagnosis. Treatment is surgical and recurrence is unlikely.
Transfection of Hippocampal Neurons with Plasmid DNA Using Calcium Phosphate Coprecipitation
Authors: Goetze Bernhard , Michael Kiebler 
Published: July 2006

INTRODUCTIONThis protocol describes transfection of plasmid DNA into primary hippocampal neurons using DNA/calcium-phosphate (CaPO4) coprecipitation. The precise pH of the transfection medium and the incubation time of cells with the coprecipitate are critical for reproducible and efficient transfection. Once these parameters are optimized for a given plasmid, the method is easily adapted for transfection of other established cell lines and primary cell cultures.
Bioresponsive Targeted Charge Neutral Lipid Vesicles for Systemic Gene Delivery
Authors: Li Weijun , Szoka Francis C. 
Published: July 2006

INTRODUCTIONThis protocol describes a stepwise procedure to prepare nucleic acids encapsulated in a polyethylene glycol (PEG)-shielded nanolipoparticle (NLP) that contain a bioresponsive lipid and ligand. This process provides several advantages for systemic gene delivery. The in vivo circulation time is extended. Also, low pH-sensitive lipids enhance DNA unpacking and endosomal escape. Finally, ligands inserted into the NLP surface can target gene delivery to specific tissues or cells in vivo.
Nonenzymatic biotinylation of a biotin carboxyl carrier protein: Unusual reactivity of the physiological target lysine
Authors: Streaker Emily D. , Beckett Dorothy 
Published: July 2006

AbstractEnzyme‐catalyzed addition of biotin to proteins is highly specific. In any single organism one or a small number of proteins are biotinylated and only a single lysine on each of these proteins is modified. A detailed understanding of the structural basis for the selective biotinylation process has not yet been elucidated. Recently certain mutants of the Escherichia coli biotin protein ligase have been shown to mediate “promiscuous” biotinylation of proteins. It was suggested that the reaction involved diffusion of a reactive activated biotin intermediate, biotinoyl‐5′‐AMP, with nonspecific proteins. In this work the reactivity of this chemically synthesized intermediate toward the natural target of enzymatic biotinylation, the biotin carboxyl carrier protein, was investigated. The results indicate that the intermediate does, indeed, react with target protein, albeit at a significantly slower rate than the enzyme‐catalyzed process. Surprisingly, analysis of the products of nonenzymatic biotinylation indicates that of five lysine residues in the protein only the physiological target side chain is modified. These results indicate that either the environment of this lysine residue or its intrinsic properties render it highly reactive to nonenzymatic biotinylation mediated by biotinoyl‐5′‐AMP. This reactivity may be important for its selective biotinylation in vivo.
Binding and signaling of surface‐immobilized reagentless fluorescent biosensors derived from periplasmic binding proteins
Authors: de Lorimier Robert M. , Tian Yaji , Hellinga Homme W. 
Published: July 2006

AbstractDevelopment of biosensor devices typically requires incorporation of the molecular recognition element into a solid surface for interfacing with a signal detector. One approach is to immobilize the signal transducing protein directly on a solid surface. Here we compare the effects of two direct immobilization methods on ligand binding, kinetics, and signal transduction of reagentless fluorescent biosensors based on engineered periplasmic binding proteins. We used thermostable ribose and glucose binding proteins cloned from Thermoanaerobacter tengcongensis and Thermotoga maritima, respectively. To test the behavior of these proteins in semispecifically oriented layers, we covalently modified lysine residues with biotin or sulfhydryl functions, and attached the conjugates to plastic surfaces derivatized with streptavidin or maleimide, respectively. The immobilized proteins retained ligand binding and signal transduction but with adversely affected affinities and signal amplitudes for the thiolated, but not the biotinylated, proteins. We also immobilized these proteins in a more specifically oriented layer to maleimide‐derivatized plates using a His2Cys2 zinc finger domain fused at either their N or C termini. Proteins immobilized this way either retained, or displayed enhanced, ligand affinity and signal amplitude. In all cases tested ligand binding by immobilized proteins is reversible, as demonstrated by several iterations of ligand loading and elution. The kinetics of ligand exchange with the immobilized proteins are on the order of seconds.
Different versions of Pseudomonas syringae pv. tomato DC3000 exist due to the activity of an effector transposon
Authors: LANDGRAF ANGELIKA , WEINGART HELGE , TSIAMIS GEORGE , BOCH JENS 
Published: July 2006

SUMMARYThe plant pathogenic bacterium Pseudomonas syringae pv. tomato strain DC3000 is a key model organism to study plant–pathogen interactions. We realized that two versions of this strain, which carry plasmids of different sizes, exist in our strain collections. The difference was located to a 9.4‐kb deletion within the larger of the two endogenous plasmids encompassing the partitioning genes parA and parB and a putative mobile element encoding the type III effector hopAM1‐2 (formerly avrPpiB2). Both plasmid variants are lost in similar frequency, indicating that the partitioning genes are not essential for stability of the plasmid. In addition, the deletion derivative strain DC3001 exhibited the same virulence towards Arabidopsis as strain DC3000. The deletion site in DC3001 is located immediately adjacent to a putative transposon that carries the effector hopX1 (formerly avrPphE), suggesting that the deletion originated from an aberrant transposition event of this element. By tagging the hopX1 transposon with an antibiotic resistance cassette on a suicide plasmid it was shown that the element is functional and produces a target site duplication of 5 bp. The plasmid also integrated into the chromosome in several cases, possibly mediated by one‐ended transposition of the hopX1 transposon. This is the first report that describes an active effector‐transposon. Comparison of DC3000 strains from several sources revealed that strains exist with differences in the endogenous plasmid composition.
The small mammal community of Mukogodo Forest, Kenya
Authors: Webala Paul W. , Muriuki George , Lala Fredrick , Bett Alice 
Published: July 2006

AbstractSpecies richness and diversity of rodents and insectivores were investigated at relict forest patches of Mukogodo, Laikipia, Kenya using Sherman's live traps and pitfall traps. Two hundred and nineteen individuals were captured in 3021 trap‐nights. There were eleven species in two taxonomic groups, Rodentia and Insectivora. Two other rodent species were sighted but not captured. Thirteen bats belonging to four species (Epomophorous wahlbergi, Pipistrellus kuhlii, Scotophilus dingani and Nycteris thebaica) were opportunistically trapped using mist nets. Two of the four species accumulation curves for forest patches did not reach an asymptote. Species richness and diversity were highest at Kurikuri compared with other patches because of habitat variability. The results support the prediction that forest disturbance and degradation lead to an increase in generalist species as compared with specialists and highlight the importance of relict afromontane forests in the conservation of small mammals in Kenya.
Changes in a Sudano‐Sahelian rodent community after slash‐and‐burn farming (Gonsé Forest, Burkina Faso)
Authors: Papillon Y. , Godron M. , Delattre P. 
Published: July 2006

AbstractThis study describes the recolonization by a Sudano‐Sahelian rodent community of an area slashed and burned in the middle of the dry season (Gonsé Forest in Burkina Faso). A series of abundance cycles occurred. The first began with the wet season and the arrival of a succession of four species: Taterillus gracilis, Tatera guineae, Nannomys sp. and Mastomys erythroleucus. Taterillus gracilis appeared to be the least demanding species. It was sexually active whatever the season and took advantage of reduced competition among species on the burned tracts. Tatera guineae also extended its spatial distribution but failed to reproduce. Nannomys sp. rapidly increased after the first rains. Although generally held to be the most prolific and opportunistic of the species involved, M. erythroleucus only found conditions amenable to its colonization late on. The timing of the disruption and whether or not it coincides with the reproductive period and the mobility phase of each species are decisive factors. This information is useful for a clearer understanding of the dynamics of each species and for evaluating the risk and probable locations of outbreaks of certain species.
Effect of voriconazole on the pharmacokinetics and pharmacodynamics of zolpidem in healthy subjects
Authors: Saari Teijo I. , Laine Kari , Leino Kari , Valtonen Mika , Neuvonen Pertti J. , Olkkola Klaus T. 
Published: July 2006

AimsTo assess the effect of voriconazole on the pharmacokinetics and pharmacodynamics of zolpidem.MethodsIn a randomized cross‐over study with two phases, 10 healthy subjects ingested 10 mg of zolpidem with or without oral voriconazole pretreatment. The concentrations of zolpidem were measured in plasma up to 24 h and pharmacodynamic variables were monitored for 12 h.ResultsVoriconazole increased the peak plasma concentration of zolpidem by 1.23‐fold [P < 0.05; 90% confidence interval (CI) 1.05, 1.45] and the area under the plasma zolpidem concentration–time curve by 1.48‐fold (P < 0.001; 90% CI 1.29, 1.74). The time to peak plasma zolpidem concentration was unchanged by voriconazole but the half‐life was prolonged from 3.2 to 4.1 h (P < 0.01; 95% CI on the difference 0.27, 1.45). The pharmacodynamics of zolpidem were unaffected by voriconazole.ConclusionVoriconazole caused a moderate increase in exposure to zolpidem in healthy young subjects but no clear pharmacodynamic changes were observed between the groups.
Using the output from global circulation models to predict changes in the distribution and abundance of cereal aphids in Canada: a mechanistic modeling approach
Authors: NEWMAN JONATHAN A. 
Published: July 2006

AbstractClimate change will alter the abundance and distribution of species. Predicting these shifts is a challenge for ecologists and essential information for the formation of public policy. Here, I use a mechanistic mathematical model of the interaction between grass growth physiology and aphid population dynamics, coupled with the climate change projections from the UK's Hadley Centre HadCM3 global circulation model (GCM) and Canada's Center for Climate Modeling and Analysis CGCM2 GCM to predict the changes in the abundance and distribution of summer cereal aphid populations in wheat‐growing regions of Canada. When used with the HadCM3 projections, the model predicts a latitudinal shift northward in abundances but there is longitudinal variation as well. However, when used with the CGCM2 projections the model predicts that continental regions will see a decline while coastal regions will see an increase in summer cereal aphid populations. These effects are stronger under the higher emissions scenarios.
Ultrasonographic guidance in pediatric regional anesthesia part 1: theoretical background
Authors: MARHOFER PETER , FRICKEY NATHALIE 
Published: July 2006

SummaryRecent findings support the use of ultrasonographic guidance in pediatric regional anesthesia. This review article illustrates basic knowledge in physics of ultrasound and ultrasonographic appearance of neuronal structures, which are prerequisites for the safe application of this technique in daily clinical practice. A critical view on education and ethics in science should emphasize future developments in ultrasonography for pediatric regional anesthesia.
Migration Regions and Population Redistribution
Authors: MORRILL RICHARD L. 
Published: July 2006

ABSTRACTCross and net migration flows among the states for 1975‐80 were used to define migration regions, or groups of states with similar patterns of net interchange. This typology may be characterized as a transition from a northeastern “core” which lost to all other regions to a northwestern “periphery” which gained from all other regions. Florida and California were found to have an important role in redistributing population. The typology was also valid for all age groups and across racial and ethnic categories. The typology remained meaningful when the 1975‐80 data were compared to 1965‐70 and 1980‐85 data, despite great volatility in net migration and significant change in the placement of many states.