bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polyethylene‐montmorillonite nanocomposites obtained by in situ polymerization of ethylene with nickel‐diimine catalysts
Authors: Mignoni Marcelo Luis , Silva Jonathan Vaz Martins , de Souza Michèle Oberson , Mauler Raquel dos Santos , de Souza Roberto Fernando , Bernardo‐Gusmão Katia 
Published: June 2011

AbstractNanocomposites of exfoliated montmorillonite in polyethylene were obtained using a combination of 1,4‐bis(2,6‐diisopropylphenyl)‐acenaphthenediimine‐dichloro‐nickel(II), montmorillonite, and methylalumoxane (MAO) or trimethylaluminum (TMA) to polymerize ethylene. The properties of the polymers were strongly influenced by the amount of clay they contained. The addition of 2.5% commercial montmorillonite (KSF or Cloisite 15A) enhanced the storage modulus from 5 to 878 MPa. Transmission electron microscopy (TEM) analyses provided evidence of exfoliation of the montmorillonite with the formation of a polyethylene nanocomposite. The enhanced mechanical properties were explained as a consequence of the reinforcement due to the presence of nanoscale layers formed from exfoliation of the clay included in the polyethylene matrix. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
On the Role of Flexibility in Protein–Ligand Interactions: the Example of p53 Tetramerization Domain
Authors: Gordo Susana , Martos Vera , Vilaseca Marta , Menéndez Margarita , de Mendoza Javier , Giralt Ernest 
Published: June 2011

AbstractThe recognition of protein surfaces by designed ligands has become an attractive approach in drug discovery. However, the variable nature and irregular behavior of protein surfaces defy this new area of research. The easy to understand “lock‐and‐key” model is far from being the ideal paradigm in biomolecular interactions and, hence, any new finding on how proteins and ligands behave in recognition events paves a step of the way. Herein, we illustrate a clear example on how an increase in flexibility of both protein and ligand can result in an increase in the stability of the macromolecular complex. The biophysical study of the interaction between a designed flexible tetraguanidinium‐calix[4]arene and the tetramerization domain of protein p53 (p53TD) and its natural mutant p53TD‐R337H shows how the floppy mutant domain interacts more tightly with the ligand than the well‐packed wild‐type protein. Moreover, the flexible calixarene ligand interacts with higher affinity to both wild‐type and mutated protein domains than a conformationally rigid calixarene analog previously reported. These findings underscore the crucial role of flexibility in molecular recognition processes, for both small ligands and large biomolecular surfaces.
Magnetic instability in a rotating layer at highly eccentric positions of the critical level
Authors: Marsenić A. , Ševčík S. 
Published: June 2011

AbstractThis study follows the numerical results presented in Marsenić & Ševčík (2010) that explored the influence of the critical level position on stability of a system. The model was a horizontal fluid layer between z = ±0.5d rotating with an angular velocity Ω = Ω0ž about the vertical axis z. The fluid was considered to be inviscid, finitely electrically conducting and incompressible and was permeated by a horizontal magnetic field B0 = ℬ︁0B0(z)y̌, where ℬ︁0 was the magnitude of the field and the function B0(z) = tanh [γ (z –z0)]. When γ is large, the field gradient is concentrated near z = z0, the critical level, the field being almost homogeneous elsewhere. In this way it controls the width of the magnetic shear layer associated with the current sheet. It was found that at conditions when the magnetic field gradient was large enough (γ = O (10)) and the critical level was placed close enough to the (bottom) perfectly conducting boundary (z0 < –0.388d for γ = 80), magnetically driven convection appeared localized to a close neighbourhood of the critical level – the so called critical layer. Based on the circumstances of its rise and its properties it was identified with the resistive tearing‐mode instability. This paper presents an analytical treatment of the problem assuming γ ≥ 1. The approach consists in separation of the computational domain into an outer region where the diffusionless limit (Elsasser number Λ → ∞) applies and an inner region (the critical layer) of finite conductivity. According to the tearing‐mode theory in classical systems, the solution in the inner region is sought as long‐wavelength with respect to the width of the critical layer. The obtained solution shows features similar to the one obtained numerically and confirmed relevance of the simplifying physical assumptions made in each region. The convection in the critical layer is strictly conditioned by a sharp magnetic shear. If the shear region is removed by further positioning of the critical level towards the perfectly conducting boundary, the localized convection disappears. It is in compliance with the fact that the system is stabilised by a perfectly conducting boundary with respect to the tearing mode. Stability is then checked numerically in the layer bounded by perfectly conducting boundaries where the critical point of the magnetic field lies on one of them. The existence of a magnetically driven instability is confirmed. Depending on the value γ, it may rise as a stationary convection (for γ < 1.5) or as a wave which for γ > 16 exhibits similarity properties (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modeling the total and polarized emission in evolving galaxies: “Spotty” magnetic structures
Authors: Arshakian T.G. , Stepanov R. , Beck R. , Krause M. , Sokoloff D. 
Published: June 2011

AbstractFuture radio observations with the Square Kilometre Array (SKA) and its precursors will be sensitive to trace spiral galaxies and their magnetic field configurations up to redshift z ≈ 3. We suggest an evolutionary model for the magnetic configuration in star‐forming disk galaxies and simulate the magnetic field distribution, the total and polarized synchrotron emission, and the Faraday rotation measures for disk galaxies at z ≲ 3. Since details of dynamo action in young galaxies are quite uncertain, we model the dynamo action heuristically relying only on well‐established ideas of the form and evolution of magnetic fields produced by the mean‐field dynamo in a thin disk. We assume a small‐scale seed field which is then amplified by the small‐scale turbulent dynamo up to energy equipartition with kinetic energy of turbulence. The large‐scale galactic dynamo starts from seed fields of 100 pc and an averaged regular field strength of 0.02 μG, which then evolves to a “spotty” magnetic field configuration in about 0.8 Gyr with scales of about one kpc and an averaged regular field strength of 0.6 μG. The evolution of these magnetic spots is simulated under the influence of star formation, dynamo action, stretching by differential rotation of the disk, and turbulent diffusion. The evolution of the regular magnetic field in a disk of a spiral galaxy, as well as the expected total intensity, linear polarization and Faraday rotation are simulated in the rest frame of a galaxy at 5GHz and 150 MHz and in the rest frame of the observer at 150 MHz. We present the corresponding maps for several epochs after disk formation. Dynamo theory predicts the generation of large‐scale coherent field patterns (“modes”). The timescale of this process is comparable to that of the galaxy age. Many galaxies are expected not to host fully coherent fields at the present epoch, especially those which suffered from major mergers or interactions with other galaxies. A comparison of our predictions with existing observations of spiral galaxies is given and discussed (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Conjunction fallacy: Causality vs. event probability
Authors: Thüring Manfred , Jungermann Helmut 
Published: June 2011

AbstractUnder certain conditions people give a conjunction of events a higher probability than one of its constituents. This finding has been called the ‘conjunction fallacy’ (Tversky and Kahneman, 1983). One such condition is when the conjunction includes a possible cause and an outcome (called ‘causal conjunctions’) because the strength of the causal link biases the probability judgment. In the present experiment we investigated whether this finding could be replicated and whether it could be reasonably attributed to causality or might be attributed alternatively to the single event probabilities, as has been suggested by Yates and Carlson (1986).120 subjects read short texts each describing two diseases. These texts varied with respect to the probability of disease A and the probability of disease B (high or low), and the causal relation between the two diseases (yes or no). Ss judged the conjunctive probabilities that a person suffered from both diseases. Causality showed neither an effect upon the judged probability of conjunctions nor upon the frequency of conjunction fallacies. The single event probabilities, on the other hand, had significant effects: conjunction fallacies occured most often when the text included a combination of high and low event probability. Our results support the assumption that (a) causality is not sufficient to induce the conjunction fallacy, and (b) single event probabilities have a major influence on conjunctive probability judgments. The mental model approach is suggested as a theoretical framework that might allow the integrative and systematic examination of causal reasoning processes.
Graphic displays in decision making — the visual salience effect
Authors: Jarvenpaa Sirkka L. 
Published: June 2011

AbstractThe study investigates the visual salience of information in making differential predictions for alpha‐numeric versus graphic displays in consumer decision making. The experiment partially supports predictions that with alpha‐numeric displays, information is acquired in correspondence with the importance weights of the attributes, whereas under graphic conditions, information is acquired in correspondence with the visual salience of the attributes. The information display form appears to have some effect not only on the temporal order in which information on attributes is acquired, but also on the relative attention given to information on attributes during the early phases of decision making.
Reluctance to vaccinate: Omission bias and ambiguity
Authors: Ritov Ilana , Baron Jonathan 
Published: June 2011

AbstractSubjects are reluctant to vaccinate a (hypothetical) child when the vaccination itself can cause death, even when this is much less likely than death from the disease prevented. This effect is even greater when there is a ‘risk group’ for death (with its overall probability held constant), even though the test for membership in the risk group is unavailable. This effect cannot be explained in terms of a tendency to assume that the child is in the risk group. A risk group for death from the disease has no effect on reluctance to vaccinate. The reluctance is an example of omission bias (Spranca, Minsk & Baron, in press), an overgeneralization of a distinction between commissions and omissions to a case in which it is irrelevant. Likewise, it would ordinarily be prudent to find out whether a child is in a risk group before acting, but in this case it is impossible, so knowledge of the existence of the risk group is irrelevant. The risk‐group effect is consistent with Frisch & Baron's (1988) interpretation of ambiguity.
Simulation of dissolved CO2 gradients in a scale‐down system: A metabolic and transcriptional study of recombinant Escherichia coli
Authors: Baez Antonino , Flores Noemí , Bolívar Francisco , Ramírez Octavio T. 
Published: June 2011

AbstractDeficient mixing in industrial‐scale bioreactors is an important concern as it results in a heterogeneous environment that may affect microbial cell physiology. Dissolved carbon dioxide (dCO2) fluctuations, which can occur in large‐scale bioreactors, were simulated for the first time and their effects were evaluated on Escherichia coli expressing recombinant green fluorescent protein (GFP). The dCO2 gradients were simulated by continuously circulating the medium between two vessels of a scale‐down system to mimic mean circulation times (tc) of 50, 170, and 375 s. Specific growth rate (μ) decreased by 11% and acetate concentration increased by 23% at the highest tc compared to reference cultures. An increase in the time needed for attaining maximum GFP concentration was also observed. The effect of dCO2 fluctuations on the transcriptional levels of genes involved in the glutamate decarboxylase (gadA and gadC) and α‐ketoglutarate dehydrogenase (sucA and sucB) were analyzed by quantitative real time PCR. Such genes are known to be highly over‐ or underexpressed at elevated constant dCO2. Expression levels of gadA and gadC increased up to 60% and 72%, and sucA decreased 1.8‐fold in the culture performed at the highest tc. Only a minor decrease of sucB expression was observed at tc of 170 and 375 s. Although exposure to continuous high dCO2 can affect culture performance, in this work it was shown that E. coli is able to rescue its metabolism in very short times when cells are intermittently returned to low dCO2 conditions after being exposed to high dCO2.
Enhancing the growth of Physcomitrella patens by combination of monochromatic red and blue light – a kinetic study
Authors: Cerff Martin , Posten Clemens 
Published: June 2011

AbstractIn the current work we demonstrate the relevance of monochromatic light conditions in moss plant cell culture. Light intensity and illumination wavelength are important cultivation parameters due to their impact on growth and chlorophyll formation kinetics of the moss Physcomitrella patens. This moss was chosen as a model organism due to its capability to produce complex recombinant pharmaceutical proteins. Filamentous moss cells were cultivated in mineral medium in shaking flasks. The flasks were illuminated by light emitting diodes (LED) providing nearly monochromatic red and blue light as well as white light as a reference. A maximum growth rate of 0.78 day(1 was achieved under additional CO2 aeration and no growth inhibition was observed under high light illumination. The application of dual red and blue light is the most effective way to reach high growth and chlorophyll formation rates while minimizing energy consumption of the LEDs. These observations are discussed as effects of photo sensory pigments in the moss. The combination of monochromatic red and blue light should be considered when a large scale process is set up.
A minimal set of bacterial cellulases for consolidated bioprocessing of lignocellulose
Authors: Liao Hehuan , Zhang Xiao‐Zhou , Rollin Joseph A. , Zhang Yi‐Heng Percival 
Published: June 2011

AbstractCost‐effective release of fermentable sugars from non‐food biomass through biomass pretreatment/enzymatic hydrolysis is still the largest obstacle to second‐generation biorefineries. Therefore, the hydrolysis performance of 21 bacterial cellulase mixtures containing the glycoside hydrolase family 5 Bacillus subtilis endoglucanase (BsCel5), family 9 Clostridium phytofermentans processive endoglucanase (CpCel9), and family 48 C. phytofermentans cellobiohydrolase (CpCel48) was studied on partially ordered low‐accessibility microcrystalline cellulose (Avicel) and disordered high‐accessibility regenerated amorphous cellulose (RAC). Faster hydrolysis rates and higher digestibilities were obtained on RAC than on Avicel. The optimal ratios for maximum cellulose digestibility were dynamic for Avicel but nearly fixed for RAC. Processive endoglucanase CpCel9 was the most important for high cellulose digestibility regardless of substrate type. This study provides important information for the construction of a minimal set of bacterial cellulases for the consolidated bioprocessing bacteria, such as Bacillus subtilis, for converting lignocellulose to biocommodities in a single step.
Hightech aus der grünen Apotheke. Biopharmazeutika aus Pflanzen
Authors: Warzecha Heribert 
Published: June 2011

AbstractPflanzen produzieren zahlreiche Stoffe, die traditionell als Arzneimittel verwendet wurden, aber auch in der modernen Medizin noch Anwendung finden. Viele neuartige Arzneistoffe allerdings sind Biopharmazeutika wie Antikörper, Hormone und Impfstoffe. Diese werden nicht mehr aus natürlichen Quellen isoliert oder synthetisiert, sondern in transgenen Organismen (Hefen, Bakterien und Säugerzellkulturen) produziert. Auch Pflanzen haben das Potenzial, als Produktionsorganismen für beispielsweise monoklonale Antikörper, Hormone wie Insulin oder bestimmte Impf‐Antigene Anwendung zu finden. Viele Studien haben gezeigt, dass Pflanzen oder pflanzliche Zellkulturen für die Produktion im Großmaßstab geeignet sind und dass in manchen Fällen die Produkte sogar klare Vorteile gegenüber anderen Produktionssystemen haben. Das betrifft sowohl die Herstellungskosten als auch die Funktionalität der therapeutischen Proteine und deren posttranslationale Modifikation. Neue Arzneipflanzen sind also möglich und werden in Zukunft hoffentlich unseren Arzneischatz bereichern.
Das Membranpotenzial. Biophysik im Experiment
Authors: Obermeyer Gerhard , Bertl Adam 
Published: June 2011

AbstractJede Zelle ist von einer Zellmembran umgeben, die das Zellinnere von der Umwelt abgrenzt und den Aufbau einer elektrischen Potentialdifferenz (Membranspannung oder Membranpotenzial) ermöglicht. Anhand von Modellmembranen (Ionenaustauschermembran) können einfache Versuche zum Verständnis des Membranpotenzials durchgeführt werden und die Ergebnisse mit den theoretischen Beschreibungen durch die Nernst‐Gleichung beziehungsweise durch die Goldman‐Hodgkin‐Huxley‐Gleichung verglichen werden.
Der Chromatin‐Code
Authors: Kronberg Inge 
Published: June 2011

AbstractTypisch für eukaryotische Zellen ist ein Zellkern mit Chromatin. Das Grundgerüst von Chromatin besteht aus Nukleosomen – eng von DNA umwickelten Histonoktameren, die Kopplungsstellen für verschiedene strukturelle und regulatorische Proteine freigeben. Schon Emil Heitz (1928) unterschied das aufgelockerte, genetisch aktive Euchromatin vom stärker kondensierten, weitgehend stillen Heterochromatin. Neue Methoden verfeinern diese Unterteilung in fünf verschiedene Chromatintypen und geben einen Einblick, wie auf diese Weise ganze Chromatinbereiche in ihrer Aktivität reguliert werden.
Mehltau‐Pilze imitieren Pollenschläuche
Authors: Brennicke Axel 
Published: June 2011

AbstractBei den blühenden Pflanzen gehören zum Sex Spermienzellen aus dem Pollen und eine Eizelle im Inneren des Stempels. Wenn ein Pollenkorn oben auf der Narbe des Stempels landet, keimt ein Zellfaden aus, der Pollenschlauch. Dieser wird durch molekulare Signale in die Nähe der Eizelle geleitet, platzt dort auf und entlässt eine Spermienzelle für die Eizelle. Pilzfäden des Mehltaus nutzen diese Moleküle für ihr Wachstum. Diese neuen Regulatoren können vielleicht für eine gezielte Resistenz gegen den Mehltau genutzt werden.
Sterilisation von Materialien und Flüssigkeiten im Autoklav
Authors: Schrödel Andrea 
Published: June 2011

AbstractWährend hitzestabile Materialien aus Glas, Keramik und Metall durch Erhitzen für 30 min auf 180°C bei trockener Luft im Ofen sterilisiert werden können, ist für die Sterilisation von Flüssigkeiten, Textilien und Kunststoffen eine Behandlung mit feuchter Hitze im Autoklav oft die Methode der Wahl: Heißer Wasserdampf ist bei gleicher Temperatur wesentlich wirksamer als trockene Wärme. Während man sich am heißen Wasserdampf beim Anheben eines Kochtopfdeckels verbrüht, kann man in den Luftstrom eines auf 250°C erhitzten Umluftherdes fassen, ohne große Schmerzen zu erleiden.
Start auf hohem Niveau: schon ursprüngliche Tiere besaßen komplexe FGF‐Rezeptoren
Authors: Hassel Monika , Rebscher Nicole 
Published: June 2011

AbstractDie Morphogenese erfordert bereits in der frühen Entwicklung eines Tieres eine feine Abstimmung zwischen Zellen, damit diese korrekt wandern und sich ausdifferenzieren können. Hierzu haben Organismen Signalsysteme entwickelt, die in der Lage sind, extrazelluläre Signale aufzunehmen, in intrazelluläre umzuwandeln und schließlich Entwicklungsgene anzusteuern. Die Evolution dieser Signalsysteme verläuft parallel zu Veränderungen der Baupläne. Diese Koevolution lässt sich anhand von Rezeptormolekülen für Fibroblasten‐Wachstumsfaktoren (FGFR) nachvollziehen.
Carl Chun – Zoologe und Tiefseeforscher
Authors: Kockerbeck Christoph 
Published: June 2011

AbstractCarl Chun war ein herausragender Meereszoologe, Spezialist für Rippenquallen und Tintenfische und Leiter der ersten deutschen Tiefsee‐Expedition mit dem Dampfer “Valdivia” in den Jahren 1898/1899.
Discrete-choice preference comparison between patients and doctors for the surgical management of oesophagogastric cancer
Authors: Thrumurthy S G , Morris J J A , Mughal M M , Ward J B 
Published: June 2011

Abstract

Background
Establishing preferences for surgery is paramount to preoperative patient counselling. This study aimed to prioritize and compare preferences of patients and doctors towards surgery for oesophagogastric cancer, to aid the counselling process.

Methods
A discrete-choice questionnaire containing hypothetical scenarios was designed to test patient preferences for six treatment attributes: mortality, morbidity, quality of life (QoL), cure rate, hospital type and surgeon's reputation. The survey was mailed to all patients who underwent oesophagogastric cancer resection from 2008 to 2009 at two teaching hospital sites. All doctors at these sites with previous experience in counselling patients for cancer surgery were also identified and presented with the survey. Results were analysed using a random-effects probit regression model. Spearman correlation was used to compare participants' implicit choices from the discrete-choice scenarios (their true preferences) with their explicit choices from the direct ranking of preferences (their perceived preferences).

Results
Eighty-one patients and 90 doctors completed the survey. Some 15 per cent of patients and 31 per cent of doctors based their choices solely on QoL. In order of importance, patients based their implicit responses on QoL (β = 1·19), cure rate (β = 0·82), morbidity (β = − 0·70), surgeon's reputation (β = 0·60), mortality (β = − 0·57) and hospital type (β = 0·26). Doctors similarly indicated QoL (β = 1·14) and hospital type (β = 0·31) as highest and lowest preferences respectively, but placed far greater emphasis on mortality (β = − 0·80) than morbidity (β = − 0·35). Implicit and explicit preferences correlated only for morbidity and surgeon's reputation in the patient cohort.

Conclusion
Clinicians may better meet patients' expectations and facilitate informed decision-making if QoL, cure rate and morbidity are emphasized foremost. A similar study employing preoperative patients is warranted for further clarification of preferences.