bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transportprozesse in der Atmosphäre
Authors: Schultz Martin , Stohl Andreas , Vogel Bernhard 
Published: June 2007

AbstractTransportvorgänge in der Atmosphäre bestimmen, wie Spurenstoffe verteilt werden und wohin sich Schadstoffwolken ausbreiten. In diesem Aufsatz werden einige Grundlagen zu atmosphärischen Transportvorgängen erörtert und die Zusammenhänge zwischen Luftchemie und Winden aufgezeigt. Anhand einiger Beispiele aus der aktuellen Forschung wird verdeutlicht, welche Bedeutung Transportprozesse auf der lokalen bis interkontinentalen Skala für die Belastung der Luft mit Schadstoffen haben können.
POPs – schwer abbaubare Chemikalien
Authors: Lammel Gerhard , Zetsch Cornelius 
Published: June 2007

AbstractPOPs, persistent organic pollutants, sind in der Umwelt schwer abbaubare, gleichzeitig bioakkumulative und toxische Stoffe. Die meisten sind mittelflüchtig und lipophil. Sie werden in der Atmosphäre zu einem erheblichen Teil an Aerosolpartikel sorbiert und nach Ablagerung am Boden oder Deposition in den Ozean in die Atmosphäre zurück verflüchtigt und können so mehrere Emissions‐Transport‐Depositions‐Zyklen durchlaufen. Die Transport‐ und Verteilungsmuster und das Ferntransport‐Potenzial sind damit ganz anders als bei herkömmlichen Luftschadstoffen, deren Transport nach Ablagerung aus der Atmosphäre endet. Dass weite Strecken durch mehrere, jeweils kürzere Wege überwunden werden können, wird als Grashüpfer‐Effekt bezeichnet. Eine wichtige Hypothese der Umweltchemie besagt, dass die beobachtete Anreicherung von vielen persistenten und bioakkumulativen Schadstoffen in den Polargebieten, fernab der Anwendungsgebiete eine Konsequenz des Grashüpfer‐Effekts sei in Verbindung mit stärkerer Kondensation in kalten Gebieten. Die Lipophilie ist die Voraussetzung für die Bioakkumulation und beeinflusst die Verteilung der Stoffe über mehrere Umweltmedien. Weil es sich bei den POPs im Allgemeinen um teilhalogenierte Stoffe handelt, ist der atmosphärische Abbau zumeist langsamer als für andere Luftschadstoffe, aber schneller als in den anderen Umweltkompartimenten, in denen erst bei Verweildauern von Monaten von Persistenz gesprochen wird. Ferntransport‐Potenzial und Persistenz eines Stoffes sind wichtig für die Einschätzung der Gefährdung, die von ihm ausgeht. Sie sind das Ergebnis des Zusammenwirkens physikalisch‐chemischer Stoffeigenschaften mit den in Raum und Zeit variablen Umweltbedingungen. Sie variieren deswegen in Raum und Zeit.
Experimente in großen Simulationskammern
Authors: Brauers Theo , Wiesen Peter 
Published: June 2007

AbstractGroße Simulationskammern bieten die Möglichkeit, auch komplexe Systeme der atmosphärischen Chemie unter vorgegebenen und gut kontrollierten Bedingungen zu untersuchen. In großen Kammern kann bei niedrigen Konzentrationen gearbeitet werden, was die Übertragbarkeit auf die reale Atmosphäre verbessert. Darüber hinaus lassen sich feldtaugliche Instrumente an der Kammer einzusetzen. In den vergangen 30 Jahren wurden wichtige Erkenntnisse zu Spurengasen und Aerosolen in Simulationskammern gewonnen. Heute werden Simulationskammern immer wichtiger bei der Entwicklung neuer Verfahren zur Untersuchung atmosphärischer Spurenstoffe sowie für den direkten Vergleich verschiedener Messverfahren.
Die Atmosphäre als photochemischer Reaktor
Authors: Wahner Andreas , Moortgat Geert 
Published: June 2007

AbstractDie Troposphäre ist ein sehr großer photochemischer Reaktor, der enorme Mengen Spurengase und Aerosole verarbeitet. Zukünftige Zunahmen der anthropogenen und natürlichen Emissionen und Aerosolbildung werden den Zustand der Troposphäre und das Klima weiter verändern. Dabei hat die “Selbstreinigungsfähigkeit” der Troposphäre eine entscheidende Bedeutung. Troposphärische Oxidation wird durch eine Reihe von Oxidationsmitteln, vor allem durch das Hydroxylradikal, OH, aber auch durch Ozon, O3, das Nitratradikal, NO3, eingeleitet. Reagieren OH‐Radikale mit Spurengasmoleküle werden sie nicht verbraucht, sondern in katalytischen Zyklen regeneriert, wobei die Konzentration der Stickoxide eine entscheidende Rolle spielt. Dieses, an einfachen Beispielen dargestellte, photochemische Reaktionssystem der Troposphäre ist generell zutreffend: nahezu alle Reaktionen von OH mit atmosphärischen Spurengasen (wie z. B. Methan, anthropogen oder biogen emittierten organischen Spurenstoffen) führen zu Kettenreaktionen, die OH‐Rradikale regenerieren. Es veranschaulicht, dass in einer NO enthaltenden Atmosphäre der Spurengasabbau unabänderlich mit der Produktion von O3 verbunden ist, die Selbstreinigungsfähigkeit und damit die Luftqualität und Klimawirkung der Troposphäre entscheidend von der troposphärischen Photochemie und den Emissionen beeinflusst wird.
Introduction of a Generally Applicable Method to Estimate Retrieval of Active Molecules for Similarity Searching using Fingerprints
Authors: Vogt Martin , Bajorath Jürgen 
Published: June 2007

AbstractFingerprints are bit string representations of molecular structure and properties and are among the most widely used computational tools for similarity searching and database screening. Various fingerprint designs are available and their search performance is in general strongly dependent on the compound classes under study and the chemical characteristics of screening databases. Currently, it is not possible to predict the probability of identifying novel hits through fingerprint searching. However, for practical applications, such estimations would be very useful because one might be able, for example, to prioritize fingerprints and compound selection strategies or decide whether or not a similarity search campaign with subsequent experimental evaluation of candidate compounds would be promising at all. We have developed a method that makes it possible to predict the outcome of similarity search calculations using any type of keyed fingerprint. The methodology incorporates bit frequency distributions of reference molecules and the screening database into an information‐theoretic function and determines the principally possible recall of active compounds within selection sets of varying size. We calibrate the function on diverse compound classes and accurately predict compound recovery in retrospective virtual screening trials. Furthermore, we correctly predict fingerprint search performance on two experimental high‐throughput screening data sets (HTS). Our findings indicate that given a set of reference molecules, a fingerprint, and a screening database, we can readily estimate how likely it will be to retrieve active compounds, without knowledge about the distribution of potential hits in the database.
Parallel Delaunay triangulation for particle finite element methods
Authors: Fragakis Yannis , Oñate Eugenio 
Published: June 2007

AbstractDelaunay triangulation is a geometric problem that is relatively difficult to parallelize. Parallel algorithms are usually characterized by considerable interprocessor communication or important serialized parts. In this paper, we propose a method that achieves high speed‐ups, but needs information regarding locally maximum element circumspheres prior to the beginning of the algorithm. Such information is directly available in iterative methods, like the particle finite element methods. The developed parallel Delaunay triangulation method, has minimum communication requirements, is quite simple and achieves high parallel efficiency. Copyright © 2007 John Wiley & Sons, Ltd.
Probing for electrical inclusions with complex spherical waves
Authors: Ide Takanori , Isozaki Hiroshi , Nakata Susumu , Siltanen Samuli , Uhlmann Gunther 
Published: June 2007

AbstractLet a physical body Ω in ℝ2or ℝ3be given. Assume that the electric conductivity distribution inside Ω consists of conductive inclusions in a known smooth background. Further, assume that a subset Γ ⊂ ∂Ω is available for boundary measurements. It is proved using hyperbolic geometry that certain information about the location of the inclusions can be exactly recovered from static electric measurements on Γ. More precisely: given a ballBwith center outside the convex hull of Ω and satisfying (B̄ ∩ ∂Ω) ⊂ Γ, boundary measurements on Γ with explicitly given Dirichlet data are enough to determine whetherBintersects the inclusion. An approximate detection algorithm is introduced based on the theory. Numerical experiments in dimension two with simulated noisy data suggest that the algorithm finds the inclusion‐free domain near Γ and is robust against measurement noise. © 2007 Wiley Periodicals, Inc.
Roles of Drosophila Kruppel‐homolog 1 in neuronal morphogenesis
Authors: Shi Lei , Lin Suewei , Grinberg Yelena , Beck Yannick , Grozinger Christina M. , Robinson Gene E. , Lee Tzumin 
Published: June 2007

AbstractThe molecular mechanisms underlying remodeling of neural networks remain largely unknown. In Drosophila, widespread neural remodeling occurs during metamorphosis, and is regulated by ecdysone. Kruppel‐homolog 1 (Kr‐h1) is a zinc finger transcription factor known to play a role in orchestrating ecdysone‐regulated transcriptional pathways and, furthermore, implicated in governing axon morphogenesis. Interestingly, in honey bee workers, neural expression of the Apis mellifera homolog of Kr‐h1 is enhanced during their transition to foraging behavior when there is increased neurite outgrowth, branching, and synapse formation. Here, we assessed the role(s) of KR‐H1 in Drosophila neuronal remodeling and morphology. We characterized the effect of Kr‐h1 expression on neuronal morphology through Drosophila larval, pupal, and adult stages. Increased expression of Kr‐h1 led to reduced branching in individual neurons and gross morphological changes in the mushroom bodies (MBs), while knocking down Kr‐h1 did not produce any obvious changes in neural morphology. Drosophila Kr‐h1 is normally expressed when MB neurons do not undergo active morphogenesis, suggesting that it may play a role in inhibiting morphogenesis. Further, loss of endogenous KR‐H1 enhanced the neuronal morphogenesis that is otherwise delayed due to defective TGF‐β signaling. However, loss of KR‐H1 alone did not affect neuronal morphogenesis. In addition, Kr‐h1 expression remains strongly linked to ecdysone‐regulated pathways: Kr‐h1 expression is regulated by usp, which dimerizes to the ecdysone receptor, and Kr‐h1 expression is essential for proper patterning of the ecdysone receptor isoforms in the late larval central nervous system. Thus, although KR‐H1 has a potential for modulating neuronal morphogenesis, it appears physiologically involved in coordinating general ecdysone signaling. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2007
House dust mite allergen activates human eosinophilsviaformyl peptide receptor and formyl peptide receptor‐like 1
Authors: Svensson Lena , Redvall Elin , Björn Camilla , Karlsson Jennie , Bergin Ann‐Marie , Rabiet Marie‐Josèphe , Dahlgren Claes , Wennerås Christine 
Published: June 2007

AbstractThe objective was to evaluate which receptors house dust mite (HDM) and birch pollen extracts engage to activate human eosinophils. Chemotaxis and degranulation were studied in eosinophils pretreated with pertussis toxin and other antagonists of G protein‐coupled receptors,e.g.the formyl peptide receptor (FPR), CC chemokine receptor 3 (CCR3) and leukotriene receptor B4 (LTB4R). Inhibition of the FPR as well as desensitization of the receptor rendered eosinophils anergic to activation by the allergens. Blockade of CCR3 or LTB4R did not affect eosinophilic reactivity. It was determined by PCR that human eosinophils express the FPR family members FPR and FPR‐like 1 (FPRL1). HDM, unlike birch pollen, evoked calcium fluxes in HL‐60 cells transfected with FPR or FPRL1. Although both allergens gave rise to calcium transients in neutrophils, which also express FPR and FPRL1, only the HDM response was decreased by the FPR antagonist. Moreover, neutrophils migrated toward HDM but not to birch pollen. Eosinophils pretreated with inhibitors of MAPK p38, ERK1/2 or protein kinase C exhibited diminished responsiveness to the aeroallergens. This study indicates that FPR and FPRL1 mediate the activation of eosinophils by HDM, whereas birch pollen employs other pathways shared with FPR to activate human eosinophils.
A Reagentless Amperometric Immunosensor for Alpha‐Fetoprotein Based on Gold Nanoparticles/TiO2 Colloids/Prussian Blue Modified Platinum Electrode
Authors: Yuan Yanru , Yuan Ruo , Chai Yaqin , Zhuo Ying , Shi Yintao , He Xiulan , Miao Xiangmin 
Published: June 2007

AbstractA novel reagentless amperometric immunosensor for the determination of alpha‐fetoprotein (AFP) was prepared by immobilizing TiO2 colloids on Prussian blue (PB) modified platinum electrode, which yielded a positively charged interface with strong adsorption to deposit gold nanoparticles for immobilization of alpha‐fetoprotein antibody (anti‐AFP). The factors influencing the performance of the proposed immunosensors were studied in detail. Under the optimized conditions, cyclic voltammograms determination of AFP showed a specific response in two concentration ranges from 3.0 to 30.0 ng/mL and from 30.0 to 300.0 ng/mL with a detection limit of 1.0 ng/mL at a signal‐to‐noise ratio of 3. The proposed immunosensor exhibited high selectivity, good reproducibility, long‐term stability (>2 months) and good repeatability.
Preparation, Characterization and Electrocatalytic Studies on Copper Complex Dye Film Modified Electrodes
Authors: Chen Shen‐Ming , Liu Jun‐Wei , Thangamuthu R. 
Published: June 2007

AbstractCopper complex dye (C.I. Direct Blue 200) film modified electrodes have been prepared by multiple scan cyclic voltammetry. The effect of solution pH and nature of electrode material on film formation was investigated. The optimum pH for copper complex film formation on glassy carbon was found to be 1.5. The mechanism of film formation on ITO seems to be similar to that on GC surface but completely different mechanism followed with gold electrode. Cyclic voltammetric features of our modified electrodes are in consistent with a surface‐confined redox process. The voltammetric response of modified electrode was found to be depending on pH of the contacting solution. UV‐visible spectra show that the nature of copper complex dye is identical in both solution phase and after forming film on electrode. The electrocatalytic behavior of copper complex dye film modified electrode towards oxidation of dopamine, ascorbic acid and reduction of SO52− was investigated. The oxidation of dopamine and ascorbic acid occurred at less positive potential on film electrode compared to bare glassy carbon electrode. Feasibility of utilizing our modified electrode in analytical estimation of dopamine, ascorbic acid was also demonstrated.
Development of an Amperometric Immunosensor for the Quantification of Staphylococcus aureus Using Self‐Assembled Monolayer‐Modified Electrodes as Immobilization Platforms
Authors: Escamilla‐Gómez Vanessa , Campuzano Susana , Pedrero María , Pingarrón José M. 
Published: June 2007

AbstractAmperometric immunosensors for the detection and quantification of S. aureus using MPA self‐assembled monolayer modified electrodes for the immobilization of the immunoreagents are reported. Two different immunosensor configurations were compared. A competitive mode, in which protein A‐bearing S. aureus cells and antiRbIgG labeled with horseradish peroxidase (HRP) compete for the binding sites of RbIgG immobilized onto the 3‐mercaptopropionic acid (MPA) modified electrode, was evaluated. Moreover, a sandwich configuration in which S. aureus cells were immobilized onto the MPA SAM, and RbIgG and antiRbIgG labeled with HRP were further linked to the electrode surface, was also tested. In both cases, TTF was used as the redox mediator of the HRP reaction with H2O2, and it was co‐immobilized onto the MPA‐modified gold electrode. After optimization of the working variables for both configurations, the analytical performance of the amperometric measurements carried out at 0.00 V (vs. Ag/AgCl) showed that the competitive immunosensor exhibited a lower limit of detection (1.6×105 S. aureus cells mL−1), as well as a better repeatability and reproducibility of the measurements.
Early Pragian conodont‐based correlations between the Barrandian area and the Spanish Central Pyrenees
Authors: Slavík Ladislav , Valenzuela‐Ríos José Ignacio , Hladil Jindřich , Carls Peter 
Published: June 2007

AbstractOccurrences and distribution of extremely scarce eognathodontids do not facilitate reliable correlation across the European regions. The correlation of the traditional early Pragian of the Prague Synform (a part of the classical Barrandian area) and the Spanish Central Pyrenees (section Segre 1) is based on conodont taxa of the Icriodus steinachensis and the Pelekysgnathus serratus stocks. This correlation has the potential to be extended to other peri‐Gondwanan regions where this scarcity of eognathodontid faunas exists as well. Application of the morphotype subdivision in I. steinachensis enables approximation of the beginning of the Pragian in the Pyrenees. It is based on the entry of I. steinachensis beta morphotype; it enters together with early eognathodontid taxa in the Barrandian sections. These correlations show that routine application of certain zonal concepts can lead to misleading conclusions. Copyright © 2007 John Wiley & Sons, Ltd.
Risk factors of cognitive decline in residential care in Hungary
Authors: Vincze Gábor , Álmos Péter , Boda Krisztina , Döme Péter , Bódi Nikoletta , Szlávik Győző , Maglóczki Erzsébet , Pákáski Magdolna , Janka Zoltán , Kálmán János 
Published: June 2007

AbstractObjectiveThe incidence of dementia is known to vary between nations due to population specific interactions of genetic and epigenetic risk factors. Since this type of data was missing from the Central‐Eastern part of Europe, especially from Hungary, an ongoing prospective multicentre study was initiated 3 years ago to determine the impact of some well‐known social and biological dementia risk factors and the prevalences and conversion rates of dementia and depression syndromes.MethodsAs part of this work, the effects of age, gender, education, smoking and alcohol consumption were investigated in residental homes‐based cohort of more than 2,100 elderly.ResultsForty‐eight percent of the entire population showed clinical signs of cognitive decline. Eighteen percent, 22%, 16% and 10% were classified as mild cognitive impairment, mild, moderate and severe stages of cognitive decline, respectively. Considered individually, all the examined dementia risk factors were significantly related to the presence of the cognitive decline. Age, female gender and regular drinking increased the risk, while smoking, higher level of education and occasional or former history of alcohol consumption were protective factors. The male gender associated regular alcohol consumption represented the strongest risk, especially with low education levels. When the different severity subgroups were compared, similar risk tendencies have been observed, but the most robust effects were associated with the most severe stages.ConclusionsThe well‐known dementia risk and protective factors are confirmed in our study. Taking these variables into consideration, the Hungarian cohort is similar to other ethnic groups in Europe. Copyright © 2007 John Wiley & Sons, Ltd.
An evaluation of a specialist multiagency home support service for older people with dementia using qualitative methods
Authors: Rothera Ian , Jones Rob , Harwood Rowan , Avery Anthony J. , Fisher Kate , James Veronica , Shaw Ian , Waite Jonathan 
Published: June 2007

AbstractBackgroundStandard home care support for people with dementia has been criticised in statutory inspection reports, and may lead to unnecessary crises, hospital or care home admissions.ObjectiveTo establish whether a specialist multiagency home care service for older people with dementia delivered better quality care than standard services, and how any improvements were achieved.DesignQualitative study, using semi‐structured interviews, focus groups and small group interviews.SettingTwo demographically similar areas in Nottingham, one served by a specialist home care team, the other by standard services.ParticipantsTwenty‐seven service users, 18 family carers, 17 home care workers, 20 health/social care professionals, across both services.ResultsThe specialist service demonstrated greater flexibility and responsiveness to the particular needs and circumstances of service users and family carers, who were encouraged to participate in routine decision‐making and activities. By sharing responsibilities, the specialist service helped reduce carer stress and prevent crises. These outcomes depended on the configuration of the service, including multidisciplinary health and social services input, careworker autonomy and independence, continuous reassessment of clients' circumstances and preferences and the capacity to develop long‐term relationships, through careworker continuity. The standard service, which used a task‐orientated approach, lacked these characteristics.ConclusionsThis study provides evidence of the benefits of a specialist multiagency home support service over standard home care, in the opinion of service users, carers and careworkers, and defines the operational model that achieves this. Findings confirm best practice recommendations, based on models of dementia care which emphasise respect for ‘personhood’. Copyright © 2007 John Wiley & Sons, Ltd.
Contaminant transport in one‐dimensional single fractured media: semi‐analytical solution for three‐member decay chain with pulse and Heaviside input sources
Authors: Shih David Ching‐Fang 
Published: June 2007

AbstractA semi‐analytical solution of the one‐dimensional transport for considering a three‐member decay chain in a single fracture with pulse and Heaviside input sources has been studied using the Laplace transform and its numerical inversion. The results reveal that breakthrough curves of dimensionless concentration for the decay chain of Np‐237, U‐233, and Th‐229 in the fracture can be well demonstrated in the temporal and spatial domains. The conditions with and without retardation effects are also compared. During the preliminary screening phase the solutions are suitable for performance assessment on radioactive waste disposal sites under a one‐dimensional single fracture condition. Copyright © 2007 John Wiley & Sons, Ltd.
A cellular automata model of surface water flow
Authors: Parsons Jay A. , Fonstad Mark A. 
Published: June 2007

AbstractPrevious cellular automata models of surface water flow have been constructed to reflect steady, gradually‐varied flow conditions. While these models are extremely important in showing the near‐equilibrium forms that result from the interactions of water and boundary material, highly dynamic forms and processes require models that represent unsteady flow conditions. In order to simulate unsteady flow in a cellular model of surface water flow, the conservation of mass and the Manning's equations are coupled with an algorithm to delay the movement of water from one pixel to the next until the correct timing is reached. This approach yields highly realistic flood wave hydrographs when compared with flood observations in the Walnut Gulch Experiment Watershed. Coupling this unsteady flow model with simple laws of sediment erosion, transport, and deposition should allow event‐based simulations of watershed and river channel geomorphologic change. Copyright © 2007 John Wiley & Sons, Ltd.