bluuebunny/crossref_metadata_2025 huggingface dataset:
Is Conditional Funding a Less Drastic Means?
Authors: Cohen-Eliya Moshe
Published: February 2009

In an age in which the regulatory state frequently deals with spending, licensing, and employment, the use of allocating powers is perceived as an appealing means by which to prevent discriminatory practices against individuals within illiberal communities. In addition to its easy availability, conditional funding is regarded as both an effective andin comparison with legal prohibitionsless drastic tool for the prevention of discrimination. Such conditions are thought to be efficient because they increase the relative cost of the discriminatory practice and in doing so create an economical incentive to avoid discrimination. Moreover, these conditions are thought to be less-coercive (in comparison with criminal law), because they still allow those subject to them to choose between the more expensive option of discrimination and the cheaper option of non-discrimination. In other words, these conditions are perceived as "Less Drastic Means." In this Article, I will argue that such a perception is false. When applied to the poor such conditionality is not less coercive than prohibitions in criminal law. It is more than reasonable to assume that attempts to rectify this flaw by exempting poor people from conditional funding will render such funding ineffective in preventing discrimination. In the final analysiswhen one takes into account both the problem of the commodification of values and the inequality between rich and poorthe use of conditional finding as a means of promoting liberal values will, in most cases, be unjust. If we believe that the antidiscrimination principle has a lexical priority over a parents right to educate their children in accordance to their culture, we should choose the path of prohibition and abandon that of conditional funding.
IRB Creep: Federal Regulations Protecting Human Research Subjects and Increasing Instructors' Responsibilities
Authors: Riordan Diane A. , Riordan Michael P.
Published: February 2009

ABSTRACT: Federal regulations require oversight of federally sponsored research involving human subjects. Universities have responded by forming Institutional Review Boards (IRBs). Although these regulations only apply to federally funded projects, universities have extended the oversight to include all projects involving human subjects. From our own experience, we observe that not all accounting faculty are aware of their responsibilities to their local boards. The sanctions for failing to follow required procedures depend on the infraction, and range from an order to cease work on the project to termination of university service for the faculty member and expulsion for the student. This report helps accounting faculty understand how the review process may affect their role as instructors and serves as encouragement to them to become familiar with the requirements of local review boards.
STM/STS investigation of carbon nanotubes deposited on Bi2Te3 surface
Authors: Bazarnik Maciej , Cegiel Maciej , Biskupski Piotr , Jazdzewska Monika , Mielcarek SÅ‚awomir , Sliwinska-Bartkowiak MaÅ‚gorzata , Czajka Ryszard
Published: February 2009

This paper reports our scanning tunneling microscopy and spectroscopy (STM/STS) study of double-walled and multi-walled carbon nanotubes (CNTs) of different diameter deposited on Bi2Te3 (narrow gap semiconductor). The approximate diameter of the studied double-walled and multi-walled CNTs was 2 nm and 8 nm, respectively. Crystalline Bi2Te3 was used as a substrate to enhance the contrast between the CNTs and the substrate in the STS measurements performed to examine peculiarities of CNT morphology, such as junctions, ends or structural defects, in terms of their electronic structure.
“Mass inflation” with lightlike branes
Authors: Guendelman Eduardo , Kaganovich Alexander , Nissimov Emil , Pacheva Svetlana
Published: February 2009

We discuss properties of a new class of p-brane models, describing intrinsically lightlike branes for any world-volume dimension, in various gravitational backgrounds of interest in the context of black hole physics. One of the characteristic features of these lightlike p-branes is that the brane tension appears as an additional nontrivial dynamical world-volume degree of freedom. Codimension one lightlike brane dynamics requires that bulk space with a bulk metric of spherically symmetric type must possess an event horizon which is automatically occupied by the lightlike brane while its tension evolves exponentially with time. The latter phenomenon is an analog of the well known “mass inflation” effect in black holes.
Social Comparison in the Classroom: A Review
Authors: Dijkstra Pieternel , Kuyper Hans , van der Werf Greetje , Buunk Abraham P. , van der Zee Yvonne G.
Published: February 2009

This article reviews research conducted on social comparison processes in the classroom since Festinger proposed his theory of social comparison. It covers the theoretical framework of social comparison theory, and it is organized around the following themes: motives for social comparison, dimensions of social comparison, direction of social comparison, and consequences of social comparison. The overall picture is an emerging one in which pupils prefer to compare their performances upward—specifically, with pupils who perform better than themselves but who resemble themselves on related and unrelated attributes. Although the magnitude of the effects of social comparison in the classroom is not examined, the review suggests that such upward comparisons not only lead pupils to perform better but evoke negative affect and lower academic self-concept. Topics discussed include inconsistencies (especially with regard to the direction of comparison and the motives underlying social comparison in the classroom), practical implications, and directions for future research.
Instructional Interventions Affecting Critical Thinking Skills and Dispositions: A Stage 1 Meta-Analysis
Authors: Abrami Philip C. , Bernard Robert M. , Borokhovski Evgueni , Wade Anne , Surkes Michael A. , Tamim Rana , Zhang Dai
Published: February 2009

Critical thinking (CT), or the ability to engage in purposeful, self-regulatory judgment, is widely recognized as an important, even essential, skill. This article describes an ongoing meta-analysis that summarizes the available empirical evidence on the impact of instruction on the development and enhancement of critical thinking skills and dispositions. We found 117 studies based on 20,698 participants, which yielded 161 effects with an average effect size ( g+) of 0.341 and a standard deviation of 0.610. The distribution was highly heterogeneous ( QT = 1,767.86, p < .001). There was, however, little variation due to research design, so we neither separated studies according to their methodological quality nor used any statistical adjustment for the corresponding effect sizes. Type of CT intervention and pedagogical grounding were substantially related to fluctuations in CT effects sizes, together accounting for 32% of the variance. These findings make it clear that improvement in students’ CT skills and dispositions cannot be a matter of implicit expectation. As important as the development of CT skills is considered to be, educators must take steps to make CT objectives explicit in courses and also to include them in both preservice and in-service training and faculty development.
Microstructures at high temperature of Fe-30 wt.% Cr-xC Alloys with x varying from 0 to 2 wt.%
Authors: Berthod Patrice , Lemoine Pierric , Ravaux Johann
Published: February 2009

Differential thermal analysis experiments and treatments for 50 h at 1000, 1100 and 1200 °C were performed for a binary Fe30Cr alloy and for six Fe30Cr (0.2 to 2 wt.%) C alloys. A complete metallographic characterization was done for all samples. The solidus and liquidus temperatures, the natures and the surface fractions of the carbide and matrix phases were determined for the three temperatures. They were compared to thermodynamic calculation results. The values and the evolutions of the solidus temperature versus the carbon content are in good agreement between experiment and calculations. It is less true for the carbide volume fractions which were obtained either by image analysis, or from the matrix Cr content. Mismatches were also observed for the liquidus temperature. Comparisons were done with the Co30CrxC and Ni30CrxC systems and with Ta-containing Fe30CrxC alloys.
Critical temperature for massive transformation in ultra-low-carbon Fe–C alloys
Authors: Liu Yongchang , Sommer Ferdinand , Jan Mittemeijer Eric
Published: February 2009

The kinetics of the isochronal austenite (γ) → ferrite (α) transformation for a series of ultra-low-carbon Fe – C alloys (with a carbon concentration from 0.001 to 0.05 at.%) were investigated for cooling rates in the range of 5 – 20 K min− 1 using high-resolution dilatometry. The rate of formation of the product (ferrite) phase as a function of time exhibits maxima. The first transformation-rate maxima pertain to diffusion-controlled ferrite growth, whereas the last, main transformation-rate maximum corresponds to massive transformation. The thus determined critical temperatures, at and below which massive transformation takes place, are always below the T0 temperatures, where the Gibbs energy of the (metastable) austenite equals that of (metastable) ferrite of the same carbon concentration, and are also below the ferrite solvus temperatures for carbon concentrations below about 0.01 at.% C and above the ferrite solvus temperatures for carbon concentrations above about 0.01 at.% C.
Recent developments in micro ceramic injection molding
Authors: Piotter Volker , Beck Martin B. , Ritzhaupt-Kleissl Hans-Joachim , Ruh Andreas , Haußelt Jürgen
Published: February 2009

Effective material application and miniaturization, both indispensable to modern product development and production, demand enhanced manufacturing processes suitable for both micro devices and economic series production. For micro parts made of polymeric materials, micro injection molding represents such a method and has already reached an industrially viable status.

For manufacturing of ceramic products micro powder injection molding is a promising option because it combines the possibility of large-scale series production with a wide range of materials, thus possessing a considerable economic potential.

An enhanced variant, micro two-component injection molding enables, for example, the fabrication of micro components consisting of two ceramic materials with different physical properties and, furthermore, significantly minimizes mounting expenditure.
Influence of Fe–F-co-doping on the dielectric properties of Ba0.6Sr0.4TiO3thick-films
Authors: Paul F. , Giere A. , Menesklou W. , Binder J. R. , Scheele P. , Jakoby R. , Haußelt J.
Published: February 2009

The influence of Fe acceptor and Fe – F acceptor – donor co-doping on the dielectric response of screen-printed Ba0.6Sr0.4TiO3thick-films on alumina substrates has been investigated. The Ba0.6Sr0.4TiO3powders were synthesized by freeze-drying of sols. Permittivity, dielectric loss, and tunability were investigated at kHz frequencies with a planar metal-insulator-metal capacitor structure, and at GHz frequencies up to 40 GHz using coplanar waveguide structures. Pure acceptor doping by Fe was found to have a distinct influence on permittivity and dielectric loss-factor at kHz-frequencies and at GHz frequencies due to an internal bias field and pairs of associated defects. Co-doping with F significantly suppresses the influence of the internal bias field and defect-associates at low and microwave frequencies. The commutation quality factor at 10 GHz and Eeff= 5.8 V μm-1was increased by co-doping the thick-films with Fe and F. Such doped Ba0.6Sr0.4TiO3films show a high potential for tunable microwave applications.
A model to calculate the viscosity of silicate melts
Authors: Grundy A. Nicholas , Jung In-Ho , Pelton Arthur D. , Decterov Sergei A.
Published: February 2009

Our recently developed model to describe the viscosity of binary silicate melts is extended to describe and predict the viscosities of multicomponent silicate melts. The viscosity of multicomponent melts containing no AlO1.5 is modeled to vary linearly as a function of the mole fractions of the basic oxides at constant SiO2 mole fraction. Systems containing AlO1.5 show a more or less pronounced viscosity maximum close to the charge compensating composition. This maximum is caused by some of the Al3+ taking on the same structural role as Si4+, thereby participating in the formation of the silica network. The network-forming Al3+ must remain associated with either one Na+, or two Al3+ ions must remain associated with one Mg2+ or Ca2+, in order to assure charge neutrality. To take this into account we introduce the associates NaAlO2, CaAl2O4 and MgAl2O4 that correspond to charge compensated network-forming Al3+. The Gibbs energy of formation of these associates determines the amount of Al3+ that takes on the network-forming role. We assume the effect on viscosity of network-forming Al3+ to be the same as Si4+ and optimize the Gibbs energies of the associates to reproduce the experimental viscosity data. Viscosities in ternary silicate systems without AlO1.5 are quantitatively predicted with no additional ternary model parameters. Ternary systems MeO
x
– SiO2 – AlO1.5 are modeled with only two temperature-independent ternary parameters per system. The model not only reproduces the magnitude of the observed viscosity maximum, but also its complex shape, asymmetry and temperature dependence.
Study of near surface changes in yttria-doped tetragonal zirconia after low temperature degradation
Authors: Marro F. G. , Chintapalli R. , Hvizdos P. , Soldera F. , Mücklich F. , Anglada M.
Published: February 2009

Full tetragonal 3 mol.% Y2O3doped zirconia has been subjected to hydrothermal ageing in water at 131 °C in order to study the change in microstructure just below the surface. The degraded layer was examined by scanning and transmission electron microscopy in a section perpendicular to the surface which was prepared by focus ion beam machining. The existence of microcracks and transformed grains in a thin surface layer of the hydrothermal degraded specimens is shown. Scratch damage in annealed and in thermally degraded specimens is compared.
Prediction of transient loading on a propeller from an approching ice block
Authors: Liu P , Colbourne B , Shin Chin
Published: February 2009

An unsteady 3D surface panel method has been developed to predict hydrodynamic load fluctuations on an ice class propeller induced by continuous variation of proximity to an ice block. The low order, time domain, combined doublet and source panel method approximates the doublet and source distribution uniformly over each panel on the propeller blades. For non-lifting bodies, i.e., the hub and ice block, only sources are distributed over the body surfaces. The simulation model is contrived in such a manner that the ice block and surrounding fluid remain stationary; and at each time step, the propeller rotates and advances forward in the inertial reference frame. This numerical model is validated with previous fixed-proximity experimental measurements and good agreement is obtained. Prediction of the fluctuating hydrodynamic load is carried out as a full dynamic interaction between the ice block and the propeller. Results for this study are compared with previous fixed-proximity numerical models and experiments. The new dynamic model establishes a basis for analysis of a more realistic fluid-structure interaction, which could, in the future, include ice block acceleration due to suction force and ice block impact loading on the propeller blade and shaft. Keywords: Marine Propulsion, Panel Methods, Unsteady Loading, Ice-Propeller Interaction doi: 10.3329/jname.v2i1.2026 Journal of Naval Architecture and Marine Engineering 2(1)(2005) 15-20
ADAM SMITH AND NEO-DARWINIAN DEBATE OVER SYMPATHY, STRONG RECIPROCITY, AND REPUTATION EFFECTS
Authors: CLARK HENRY C.
Published: February 2009

This paper aims to do two things. First, it describes the place that Adam Smith actually occupies in current research occurring at the boundaries of new interdisciplinary social-science fields such as evolutionary anthropology, evolutionary psychology, neuro-economics and behavioral economics. Second, it suggests a way in which Smith's place in the debates with which these subjects are concerned may be more properly defined and conceptualized. Specifically, the paper focuses on the controversial new theory of strong reciprocity, and on the reputation effects that its critics think that theory neglects.
DAVID HUME ON MONETARY POLICY: A RETROSPECTIVE APPROACH
Authors: PAGANELLI MARIA PIA
Published: February 2009

Monetary policy is a modern idea of which David Hume is generally considered a precursor. Moreover, thanks to Milton Friedman and Robert Lucas, he is often presented as one of the first and most illustrious endorser of monetarism. This paper argues against this view, and in agreement with Joseph Schumpeter, that Hume's contribution to economics, while not insignificant, cannot claim any real novelties. It offers an interpretation of Hume as a descendant of a pre-modern understanding of money rather than a forerunner of modern monetary ideas, and as a scholar exposing common ideas of his time rather than a prophet of economic theories developed centuries later, and argues that there is little in Hume that resembles today's monetary policy prescriptions.
Concepts of Entropy and Their Applications
Authors: Broadbridge Phil , Guttmann Anthony J.
Published: February 2009

Since a connection was made in the 19th Century between increase of entropy and earlier expressions of the Second Law of Thermodynamics, the topic has continued to fascinate engineers, physicists, chemists, computer scientists, mathematicians and philosophers. The topic of entropy is very much alive, as witnessed by the highly cited proceedings of a lively conference on the subject, held in Dresden Germany in 2000 [1]. Our intention in running a theme program seven years after the Dresden conference was to stimulate connections between entropy theory and broader applications. The papers in this special issue arose from a meeting of the AMSI-MASCOS Theme Program, Concepts of Entropy and their Applications, which took place in Melbourne Australia, November 26- December 12, 2007. [...]
A complexTFAP2Aallele is associated with branchio‐oculo‐facial syndrome and inner ear malformation in a deaf child
Authors: Tekin Mustafa , Sırmacı Aslı , Yüksel‐Konuk Berrin , Fitoz Suat , Sennaroğlu Levent
Published: February 2009

We present a 4‐year‐old girl with congenital profound sensorineural deafness associated with inner ear malformation (incomplete partition type II, enlarged vestibule, and enlarged vestibular aqueduct). The proposita also had pseudocleft lips, skin defects, auricle abnormalities, and unilateral multicystic dysplastic kidney, leading to the diagnosis of branchio‐oculo‐facial (BOF) syndrome. Mutation analysis of theTFAP2Agene showed a de novo deletion of 18 and insertion of 6 nucletiodes, resulting in deletion of amino acids LPGARR and insertion of RI between amino acids 276 and 281. Altered amino acids are located within the basic DNA binding and dimerization domains of TFAP2A. Previously reported amino acid substitutions in TFAP2A involved only DNA binding domain in four patients with BOF syndrome who were not reported to have profound sensorineural deafness. Our report implies that the localization of mutations inTFAP2Amight be responsible with the phenotypic findings in BOF syndrome. © 2009 Wiley‐Liss, Inc.
Molecular cytogenetic characterization of the first reported case of inv dup del 20p compatible with a U‐type exchange model
Authors: Leclercq Sandrine , Maincent Kim , Baverel Françoise , Tessier Dominique Le , Letourneur Franck , Lebbar Aziza , Dupont Jean‐Michel
Published: February 2009

Inverted duplications with terminal deletions have been reported for an increasing number of chromosome ends. The best characterized and most frequent rearrangement reported involves the short arm of chromosome 8. It derives from non‐allelic homologous recombination (NAHR) between two inverted LCRs (low copy repeats) of the olfactory receptor (OR) gene cluster during maternal meiosis. We report here on the cytogenetic characterization of the first inversion duplication deletion involving the short arm of chromosome 20 (inv dup del 20p) in an 18‐month‐old boy presenting with clinical signs consistent with 20p trisomy syndrome. This abnormality was suspected on karyotyping, but high‐resolution molecular cytogenetic investigations were required to define the breakpoints of the rearrangement and to obtain insight into the mechanism underlying its formation. The duplicated region was estimated to be 18.16 Mb in size, extending from 20p13 to 20p11.22, and the size of the terminal deletion was estimated at 2.02 Mb in the 20p13 region. No single copy region was detected between the deleted and duplicated segments. As neither LCR nor inversion was identified in the 20p13 region, the inv dup del (20p) chromosome abnormality probably did not arise by NAHR. The most likely mechanism involves a break in the 20p13 region, leading to chromosome instability and reparation by U‐type exchange or end‐to‐end fusion. © 2009 Wiley‐Liss, Inc.
Genetic assessment of breast cancer risk in primary care practice
Authors: Burke Wylie , Culver Julie , Pinsky Linda , Hall Sarah , Reynolds Susan E. , Yasui Yutaka , Press Nancy
Published: February 2009

Family history is increasingly important in primary care as a means to detect candidates for genetic testing or tailored prevention programs. We evaluated primary care physicians' skills in assessing family history for breast cancer risk, using unannounced standardized patient (SP) visits to 86 general internists and family medicine practitioners in King County, WA. Transcripts of clinical encounters were coded to determine ascertainment of family history, risk assessment, and clinical follow‐up. Physicians in our study collected sufficient family history to assess breast cancer risk in 48% of encounters with an anxious patient at moderate risk, 100% of encounters with a patient who had a strong maternal family history of breast cancer, and 45% of encounters with a patient who had a strong paternal family history of breast and ovarian cancer. Increased risk was usually communicated in terms of recommendations for preventive action. Few physicians referred patients to genetic counseling, few associated ovarian cancer with breast cancer risk, and some incorrectly discounted paternal family history of breast cancer. We conclude that pedigree assessment of breast cancer risk is feasible in primary care, but may occur consistently only when a strong maternal family history is present. Primary care education should focus on the link between inherited breast and ovarian cancer risk and on the significance of paternal family history. Educational efforts may be most successful when they emphasize the value of genetic counseling for individuals at risk for inherited cancer and the connection between genetic risk and specific prevention measures. © 2009 Wiley‐Liss, Inc.
Generalized arterial calcification of infancy: Phenotypic spectrum among three siblings including one case without obvious arterial calcifications
Authors: Dlamini Nomazulu , Splitt Miranda , Durkan Anne , Siddiqui Ata , Padayachee Soundrie , Hobbins Sue , Rutsch Frank , Wraige Elizabeth
Published: February 2009

Generalized arterial calcification of infancy (GACI) (OMIM no. 208000) is characterized by calcification of the major arteries and soft tissues and associated with mutations in the ENPP1 gene. Most affected patients die within the first 6 months of life although prolonged survival is increasingly recognized. We report on three siblings with GACI and striking phenotypic variability. Two siblings (including the sibling survivor) were compound heterozygotes for mutations in exon 7 (c.783C>G (p.Y261X)) and exon 8 (c. 878_879delAA (p.K293fsX5)) of the ENPP1 gene confirming the diagnosis of GACI. The sibling survivor did not have calcification on X‐ray studies or evidence of hypophosphatemic rickets. GACI may be under recognized and we emphasize consideration of this condition in patients with multiple arterial stenosis even in the absence of radiographic calcification. This adds to the expanding phenotype of GACI and supports a potential role for modifying genes. © 2009 Wiley‐Liss, Inc.
A recurrent EYA1 mutation causing alternative RNA splicing in branchio‐oto‐renal syndrome: Implications for molecular diagnostics and disease mechanism
Authors: Stockley Tracy L. , Mendoza‐Londono Roberto , Propst Evan J. , Sodhi Sandi , Dupuis Lucie , Papsin Blake C.
Published: February 2009

Branchio‐oto‐renal syndrome is a heterogeneous disorder inherited in an autosomal dominant pattern, characterized by branchial arch abnormalities, hearing loss and renal abnormalities, with mutations in EYA1 reported in 30–70% of patients. We have applied a molecular testing strategy of sequencing of the complete coding region/flanking intronic regions and multiple ligation probe amplification analysis of EYA1 to a pediatric branchio‐oto‐renal proband cohort. EYA1 mutations were identified in 82% (14/17) of the probands. We also describe a novel recurrent EYA1 mutation c.867 + 5G > A found in five unrelated affected patients. RNA analysis showed that c.867 + 5G > A affects EYA1 splicing, producing an aberrant mRNA transcript lacking exon 8 and resulting in premature termination in exon 9. The aberrant transcript was present at approximately 50% level of wild‐type EYA1 mRNA in fibroblasts, and is predicted to encode an EYA1 protein retaining the amino terminal transcriptional coactivator region but lacking the conserved carboxy terminal Eya phosphatase domain. Patients with the c.867 + 5G > A mutation were found to have more severe renal abnormalities than probands with other mutations in this cohort. Analysis of the c.867 + 5G > A mutation suggests that certain transcripts of EYA1 escape nonsense‐mediated decay and encode truncated EYA proteins that may be capable of dominant‐negative interactions producing distinct phenotypic features within the branchio‐oto‐renal spectrum. © 2009 Wiley‐Liss, Inc.
Locomotor variation and bending regimes of capuchin limb bones
Authors: Demes Brigitte , Carlson Kristian J.
Published: February 2009

Primates are very versatile in their modes of progression, yet laboratory studies typically capture only a small segment of this variation. In vivo bone strain studies in particular have been commonly constrained to linear locomotion on flat substrates, conveying the potentially biased impression of stereotypic long bone loading patterns. We here present substrate reaction forces (SRF) and limb postures for capuchin monkeys moving on a flat substrate (“terrestrial”), on an elevated pole (“arboreal”), and performing turns. The angle between the SRF vector and longitudinal axes of the forearm or leg is taken as a proxy for the bending moment experienced by these limb segments. In both frontal and sagittal planes, SRF vectors and distal limb segments are not aligned, but form discrepant angles; that is, forces act on lever arms and exert bending moments. The positions of the SRF vectors suggest bending around oblique axes of these limb segments. Overall, the leg is exposed to greater moments than the forearm. Simulated arboreal locomotion and turns introduce variation in the discrepancy angles, thus confirming that expanding the range of locomotor behaviors studied will reveal variation in long bone loading patterns that is likely characteristic of natural locomotor repertoires. “Arboreal” locomotion, even on a linear noncompliant branch, is characterized by greater variability of force directions and discrepancy angles than “terrestrial” locomotion (significant for the forearm only), partially confirming the notion that life in trees is associated with greater variation in long bone loading. Directional changes broaden the range of external bending moments even further. Am J Phys Anthropol, 2009. © 2009 Wiley‐Liss, Inc.
Symbol der Chemie: Das Periodensystem der chemischen Elemente im jungen Jahrhundert
Authors: Wang Shu‐Guang , Schwarz W. H. Eugen
Published: February 2009

Auf dem Prüfstand: Das Periodensystem der Elemente (PSE) wird seit kurzem theoretisch besser verstanden. Die großen Energielücken oberhalb der Edelgasschalen 1s2undnp6(n=2–6) drängen dem ganzen PSE eine Periodizität auf, und mit Reihe 7 ist das PSE komplett. Es zeigt sich, dass die Elektronenkonfigurationen freier Atome chemisch irreführend sind und die (n+l)‐Regel ein Beispiel für die „Erfindung von Tatsachen“ auch in den harten Naturwissenschaften ist.

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Exploiting a Bacterial Drug‐Resistance Mechanism: A Light‐Activated Construct for the Destruction of MRSA
Authors: Zheng Xiang , Sallum Ulysses W. , Verma Sarika , Athar Humra , Evans Conor L. , Hasan Tayyaba
Published: February 2009

Bakterien ein Strich durch die Rechnung: Ein enzymspezifisches Molekülkonstrukt macht sich die Überexpression von β‐Lactamase in wirkstoffresistenten Bakterien zu Nutze. Man beobachtet eine spezifische photodynamische Toxizität gegen β‐Lactam‐resistente methicillinresistente Staphylococcus aureus (MRSA), wobei der übliche Mechanismus der Antibiotikaresistenz – die Spaltung des β‐Lactam‐Rings – die phototoxische Komponente freisetzt (siehe Bild; Q: Fluoreszenzlöscher)

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Umwandlung der absoluten Konfiguration einzelner Adsorbatkomplexe
Authors: Parschau Manfred , Passerone Daniele , Rieder Karl‐Heinz , Hug Hans J. , Ernst Karl‐Heinz
Published: February 2009

Chiralitätsumkehr durch Elektronen: Propenmoleküle bilden chirale Komplexe bei Adsorption auf einer Kupferoberfläche. Inelastisch gestreute Tunnelelektronen aus der Spitze eines Rastertunnelmikroskops regen molekulare Schwingungen an, die zur Rotation oder Diffusion des Adsorbats auf der Oberfläche führen. Bei höheren Tunnelströmen wird auch die Umwandlung in die entgegengesetzte Konfiguration beobachtet.

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Nanoscale Chemical Imaging of the Reduction Behavior of a Single Catalyst Particle
Authors: de Smit Emiel , Swart Ingmar , Creemer J. Fredrik , Karunakaran Chithra , Bertwistle Drew , Zandbergen Henny W. , de Groot Frank M. F. , Weckhuysen Bert M.
Published: February 2009

Katalysator unter der Lupe: Die Untersuchung der Reduktion an einem Fischer‐Tropsch‐Katalysatorpartikel mithilfe von In‐situ‐Röntgentransmissionsmikroskopie im Rastermodus zeigte bei einer räumlichen Auflösung von 35 nm eine ungleichmäßige Verteilung von Fe0‐, Fe2+‐ und Fe3+‐Spezies. Regionen mit unterschiedlichen Reduktionseigenschaften können abgegrenzt werden; ihr Zustandekommen lässt sich auf der Grundlage lokaler chemischer Wechselwirkungen und der Katalysatormorphologie erklären.

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Color Tunability and Electrochemiluminescence of Silver Nanoclusters
Authors: Díez Isabel , Pusa Matti , Kulmala Sakari , Jiang Hua , Walther Andreas , Goldmann Anja S. , Müller Axel H. E. , Ikkala Olli , Ras Robin H. A.
Published: February 2009

Bunte Cluster: Die optischen Absorptions‐ und Emissionsbanden von Silbernanoclustern aus nur ein paar Atomen reagieren sehr empfindlich auf die chemische Umgebung, d. h., die Cluster sind ausgesprochen solvatochrom (siehe Bild). Mit ihren photophysikalischen Eigenschaften und ihrer Elektrochemilumineszenz haben die Ag‐Cluster deutliche Vorteile gegenüber größeren Nanopartikeln z. B. in molekularen Sensoranwendungen.

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Stereoselective Synthesis of cis‐β‐Methyl‐ and Phenyl‐Substituted Alkenylboronates by Platinum‐Catalyzed Dehydrogenative Borylation
Authors: Ohmura Toshimichi , Takasaki Yuta , Furukawa Hideki , Suginome Michinori
Published: February 2009

Changing places: Intramolecular B(pin)/H exchange took place in the presence of a platinum–phosphane catalyst, giving synthetically useful cis‐β‐methyl‐substituted alkenylboronates stereoselectively (see scheme; B(pin)=4,4,5,5‐tetramethyl‐1,3,2‐dioxaborolan‐2‐yl).

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The effect of electrode configuration and substrate material on the mass deposition rate of electrospinning
Authors: Stanger Jonathan , Tucker Nick , Wallace Andrew , Larsen Nigel , Staiger Mark , Reeves Roger
Published: February 2009

Poly(vinyl alcohol) (PVOH) was electrospun using different methods to charge the polymer solution. A positive high voltage relative to the collecting electrode significantly increased the fiber deposition rate. Electron microscopy showed that approximately half of the increase in fiber mass was due to thicker fibers being deposited. The current flowing from the grounded electrode was measured to determine the charge carried on the PVOH jet. This showed that for a positive voltage charging condition there is a much larger current and hence more charge carriers generated in the PVOH solution. As a result, more mass is ejected from the Taylor cone, implying that a positive voltage also produces longer fiber for a given time period. We also tested whether different substrate materials caused any variation when the charging conditions were changed. Statistically significant variation between substrates was only found when the substrate was an insulator and was expected to support a high‐deposition rate. This confirms the view that the PVOH fiber arrives at the collecting electrode carrying a charge that must be neutralized, otherwise a repulsive charge will form where the fiber is deposited and some fiber will be lost to any alternative earth. In electrospraying, charge carriers are generated using associated redox reactions. Thus, for electrospinning a lack of symmetry in these reactions may result in the generation of different quantities of charge carriers in the PVOH solution and changes in the mass deposition rate of electrospun fiber. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Mobile information retrieval with search results clustering: Prototypes and evaluations
Authors: Carpineto Claudio , Mizzaro Stefano , Romano Giovanni , Snidero Matteo
Published: February 2009

Web searches from mobile devices such as PDAs and cell phones are becoming increasingly popular. However, the traditional list‐based search interface paradigm does not scale well to mobile devices due to their inherent limitations. In this article, we investigate the application of search results clustering, used with some success for desktop computer searches, to the mobile scenario. Building on CREDO (Conceptual Reorganization of Documents), a Web clustering engine based on concept lattices, we present its mobile versions Credino and SmartCREDO, for PDAs and cell phones, respectively. Next, we evaluate the retrieval performance of the three prototype systems. We measure the effectiveness of their clustered results compared to a ranked list of results on a subtopic retrieval task, by means of the device‐independent notion of subtopic reach time together with a reusable test collection built from Wikipedia ambiguous entries. Then, we make a cross‐comparison of methods (i.e., clustering and ranked list) and devices (i.e., desktop, PDA, and cell phone), using an interactive information‐finding task performed by external participants. The main finding is that clustering engines are a viable complementary approach to plain search engines both for desktop and mobile searches especially, but not only, for multitopic informational queries.
Gebäude aus Lebenszyklusperspektive – Ökobilanzen im Bauwesen
Authors: Wittstock Bastian , Albrecht Stefan , Colodel Cecilia Makishi , Lindner Jan Paul
Published: February 2009

Die Frage nach den Umweltwirkungen von Produkten gewinnt aufgrund der zunehmenden Forderung nach der Berücksichtigung des Nachhaltigkeitsgedankens im Bauwesen stetig an Bedeutung. Die Ökobilanz ist eine Methode, um die ökologischen Wirkungen eines technischen Systems – im Bauwesen kann das z. B. ein Bauprodukt, aber auch ein gesamtes Gebäude sein – entlang dessen gesamten Lebenszyklus darzustellen. Ökobilanzen von Bauprodukten sind seit Jahren etabliert, während Ökobilanzen von Gebäuden erst allmählich Verbreitung finden. Insbesondere das Deutsche Gütesiegel Nachhaltiges Bauen fördert diese Entwicklung durch die Einbeziehung des gesamten Lebenszyklus in die Nachhaltigkeitsbewertung von Gebäuden. Bauschaffende haben sich allerdings gerade der Herausforderung der ökologischen Optimierung eines Bauwerks bereits bei dessen Planung zu stellen. Mit Hilfe von Kooperationen zwischen Ökobilanz‐Experten und Fachleuten der Planung und des Baubetriebs können geeignete Lösungen für diese Aufgabe entwickelt werden. Dieser Aufsatz stellt eine Übersicht über Grundsätze und Anwendungen von Ökobilanzen im Bauwesen zusammen und zeigt einen Lösungsansatz für die Frage nach der planungsintegrierten ökologischen Optimierung auf (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Das Landschaftsgedächtnis der Bienen. Kleine Gehirne – überraschendes Orientierungsvermögen
Authors: Menzel Randolf
Published: February 2009

Mit einem neuen Gerät, dem harmonischen Radar, kann der Flug von einzelnen Bienen kontinuierlich verfolgt werden. Dabei zeigt sich, dass Bienen sich in dem von ihnen erkundeten Gelände gut auskennen. Versetzt man sie an einen unerwarteten Ort, sind sie nicht verloren, sondern finden nach einer Suchphase zu ihrem Stock auf direktem Flug zurück. Kennen Bienen eine Futterstelle, dann können sie auch diese ansteuern. Das Navigationsgedächtnis der Bienen ist also so organisiert, dass sie zwischen zwei Zielorten entscheiden kann, die sie von ihrem Ausgangspunkt nicht einsehen kann, und die sie dann direkt ansteuert. Daraus schließen wir, dass sie sich nach einem kartenartigen Raumgedächtnis orientieren.
Papillomviren und Krebs. Wie aus einem Anfangsverdacht ein Impfstoff wurde
Authors: Gissmann Lutz , Schädlich Lysann , Senger Tilo
Published: February 2009

Epidemiologische Untersuchungen deuteten schon lange darauf hin, dass Zervixkarzinome als Folge einer durch Geschlechtsverkehr übertragenen Infektion entstehen. Papillomviren des Menschen (HPV) wurden als verantwortliche Agentien vorgeschlagen, da Mitglieder der Papillomvirus‐Familie bei Tieren Tumore auslösen können und HPV‐Infektionen im Genitaltrakt des Menschen häufig vorkommen. Verschiedene Befunde – Entdeckung der Vielfalt der Papillomviren, regelmäßiger Nachweis der Genome bestimmter, sog. Hochrisiko‐HPV‐Typen in Tumorbiopsien, Verständnis des Mechanismus der Zelltransformation, sowie informative epidemiologische Studien – führten schließlich zum Konsens, dass Infektionen mit diesen Viren Zervixkarzinome und andere Krebsformen des Menschen verursachen können. Diese Kenntnis führte letztendlich zur Entwicklung von Impfstoffen als Mittel der Krebsprävention.
Mechanische Experimente an lebenden Zellen. Perspektiven für die Krebsforschung
Authors: Mierke Claudia Tanja , Koch Thorsten Michael , Mierke Claudia Tanja
Published: February 2009

Dem Prozess der Zellmigration liegen physikalische Gesetzmäßigkeiten zu Grunde. Ein tiefergehendes Verständnis der Mechanik lebender Zellen ist bei zellulären Prozessen wie z.B. der Migration von Tumorzellen durch eine 3‐D‐Matrix von entscheidender Bedeutung. Es könnte sich ein zellmechanischer Parameter – besser als einzelne Proteine – als Marker eignen, um routinemäßig in der Tumordiagnostik eingesetzt zu werden. Die Erforschung der Mechanik von lebenden Zellen trägt zu einem besseren Verständnis von Krebserkrankungen bei – insbesondere bei dem Prozess der Tumor‐Metastasierung durch Invasion von Krebszellen in das Bindegewebe.
Martin Lindauer – ein Leben für die Bienenforschung
Authors: Daumer Karl
Published: February 2009

Martin Lindauer, der bekannteste und erfolgreichste Schüler des Nobelpreisträgers Karl von Frisch, hat mit seinen eigenen Bienenforschungen und denen seiner herausragenden Schüler die klaren Fragestellungen und scharfsinnigen Methoden seines Lehrmeisters konsequent fortgeführt. Er konnte damit die Einsichten in die erstaunlichen Sinnes‐ und Verhaltensleistungen der Bienen eindrucksvoll erweitern. Am 13. November 2008, rund einen Monat vor seinem 90.Geburtstag, ist er nach langem Leiden an der Parkinson'schen Krankheit verstorben.
Simulation of the Carbonate Looping Process for Post‐Combustion CO2 Capture from a Coal‐Fired Power Plant
Authors: Ströhle J. , Lasheras A. , Galloy A. , Epple B.
Published: February 2009

The present contribution focuses on the carbonate looping process, i.e., post‐combustion CO2 capture by means of CaO containing solid sorbents in a system of two circulating fluidized bed reactors. Material and energy balances were performed using the ASPEN PLUSTM software. Two different modeling approaches are applied to the carbonator. First, the entire active fraction of CaO is assumed to be converted; second, the CO2 absorption efficiency in the circulating fluidized bed is calculated using an analytical 1D model for fast fluidization. The absorption of SO2 by CaO is taken into account. The overall plant efficiency depends on the mass flows of fresh limestone and circulating CaO. The process is shown to be economically feasible, having low energy penalties in comparison with other CO2 capture technologies and it seems to be suited for retro‐fitting existing power plants.
A Comparison Study of Rhodamine B Photodegradation over Nitrogen‐Doped Lamellar Niobic Acid and Titanic Acid under Visible‐Light Irradiation
Authors: Li Xiukai , Kikugawa Naoki , Ye Jinhua
Published: February 2009

Slip between the sheets! The intercalation properties of lamellar solid acids have a profound impact on nitrogen doping as well as on the resultant visible‐light photocatalysis, and the effects depend strongly on the protonic acidities of the samples (see figure).

magnified image

A solid‐state reaction method with urea as a nitrogen precursor was used to prepare nitrogen‐doped lamellar niobic and titanic solid acids (i.e., HNb3O8 and H2Ti4O9) with different acidities for visible‐light photocatalysis. The photocatalytic activities of the nitrogen‐doped solid acids were evaluated for rhodamine B (RhB) degradation and the results were compared with those obtained over the corresponding nitrogen‐doped potassium salts. Techniques such as XRD, BET, SEM, X‐ray photoelectron spectroscopy, and UV‐visible diffuse reflectance spectroscopy were adopted to explore the nature of the materials as well as the characteristics of the doped nitrogen species. It was found that the intercalation of the urea precursor helped to stabilize the layered structures of both lamellar solid acids and enabled easier nitrogen doping. The effects of urea intercalation were more significant for the more acidic HNb3O8 sample than for the less acidic H2Ti4O9. Compared with the nitrogen‐doped KNb3O8 and K2Ti4O9 samples, the nitrogen‐doped HNb3O8 and H2Ti4O9 solid acids absorb more visible light and exhibit a superior activity for RhB photodegradation under visible‐light irradiation. The nitrogen‐doped HNb3O8 sample performed the best among all the samples. The results of the current study suggest that the protonic acidity of the lamellar solid‐acid sample is a key factor that influences nitrogen doping and the resultant visible‐light photocatalysis.
Construction of Helical J‐Aggregates Self‐Assembled from a Thymidylic Acid Appended Anthracene Dye and DNA as a Template
Authors: Iwaura Rika , Ohnishi‐Kameyama Mayumi , Iizawa Tomohiko
Published: February 2009

Driven round the twist by DNA: One‐dimensional helical J‐aggregates are formed by the self‐assembly of thymidylic acid appended anthracene dye (shown in red and yellow) in the presence of complementary single‐stranded oligoadenylic acid (shown in green and blue) in an aqueous solution.

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The thymidylic acid appended anthracene dye 2,6‐bis[5‐(3′‐thymidylic acid)pentyloxy]anthracene (1) was synthesized, and the self‐assembly of 1 and the binary self‐assembly of 1 with a complementary single‐stranded 20‐meric oligodeoxyadenylic acid (dA20) were performed in 0.1×TE buffer solution (i.e., 1.0×10−3 M Tris‐HCl, 1.0×10−4 M ethylenediaminetriacetic acid (EDTA)). The characteristic J‐band, small Stokes shift (6 nm), Cotton effect, and helical nanofibers 5.1 nm in diameter are observed in UV/Vis, fluorescence, and circular dichroism (CD) spectroscopies and atomic force microscopy (AFM) measurements for the binary self‐assembly of 1 and dA20 in aqueous solution. These observations revealed that the helical J‐aggregates, in which the short‐axis transition dipoles of the anthracene moieties are aligned in a head‐to‐tail fashion, are formed from the binary self‐assembly of 1 and dA20. The UV/Vis absorption and CD band of the anthracene La region were found to be strongly dependent on temperature and showed cooperative changes for the binary self‐assembly of 1 and dA20. The self‐assembly of the single‐component 1 produced right‐ and left‐handed helical nanofibers with diameters ranging from 4.0 to 10 nm. In contrast, for the binary self‐assembly, the UV/Vis and fluorescence spectra showed no J‐band and the Stokes shift was at approximately 107 nm for the single‐component 1 in aqueous solution. In addition, the binary self‐assembly of 1 and noncomplementary single‐stranded 20‐meric oligothymidylic acid (dT20) showed a small J‐band and the J‐band disappeared at 50 °C upon heating. On the basis of these observations, we concluded that thymine–adenine base‐pair formation induced supramolecular helical J‐aggregates in the binary self‐assembly of 1 and dA20 in aqueous solutions.
Reaktion mit integrierter Extraktion für homogen katalysierte Flüssigphasenreaktionen
Authors: Behr A. , Seuster J.
Published: February 2009

Bei der Anwendung der homogenen Übergangsmetallkatalyse in großtechnischen Prozessen ist ein geeignetes Katalysatorrecycling von entscheidender Bedeutung, um die Verluste an teurem Katalysatormetall und an kostspieligen Liganden zu minimieren. Die Reaktivextraktion als integrierte Reaktions‐ und Trennoperation bietet hierzu einen möglichen Ansatz. Das Prinzip besteht darin, die Reaktion in einer katalytisch aktiven Flüssigphase durchzuführen und eine zweite, katalytisch inaktive, Flüssigphase dazu zu nutzen, das Produkt vom Katalysator zu trennen und aus dem Reaktor herauszuführen. Am Beispiel der Palladium‐katalysierten Telomerisation von Butadien mit Ethylenglykol konnte unter Nutzung der Reaktivextraktion ein neuer Prozess entwickelt und im Labor‐ sowie Miniplantmaßstab eingehend untersucht werden.
Analysis of cell movement by simultaneous quantification of local membrane displacement and fluorescent intensities using Quimp2
Authors: Bosgraaf Leonard , van Haastert Peter J.M. , Bretschneider Till
Published: February 2009

The use of fluorescent markers in living cells has increased dramatically in the recent years. The quantitative analysis of the images requires specific analysis software. Previously, the program Quimp was launched for quantitating fluorescent intensities at the membrane or the cortex of the cell. However, Quimp is not well suited to quantitate local membrane displacement. Here we present Quimp2 that is capable of tracking membrane subregions in time, which enables the simultaneous quantification of fluorescent intensities and membrane movement. Quimp2 has two new tools, (i) conversion filters to analyze movies obtained with fluorescent, DIC and phase contrast different microscopes, and (ii) a macro that calculates the local membrane displacement and provides various options to display the results. Quimp2 is used here to investigate the molecular mechanism of cell movement by correlating the dynamics of local membrane movement with the local concentration of myosin and F‐actin. Cell Motil. Cytoskeleton, 2009. © 2009 Wiley‐Liss, Inc.