bluuebunny/crossref_metadata_2025 huggingface dataset:
Zukünftige Bemessung von Mauerwerk – Genaueres Verfahren
Authors: Graubner Carl‐Alexander , Brehm Eric , Kranzler Thomas
Published: September 2009

Nach intensiven Vorarbeiten in den zuständigen Normungsgremien wurde der Fachöffentlichkeit im März dieses Jahres eine Neufassung der Bemessungsnorm DIN 1053 für unbewehrte Mauerwerkswände als “Gelbdruck” vorgestellt, welche deutliche Änderungen im Vergleich zu den derzeit gültigen Vorschriften DIN 1053‐1:1996‐11 [1] und DIN 1053‐100:2007‐09 [2] aufweist. In die Überarbeitung sind vielfältige Forschungsaktivitäten der letzten Jahre, insbesondere auf dem Gebiet der Ermittlung der Querkrafttragfähigkeit, eingeflossen, weshalb ein auf dem neuesten Stand des Wissens basierendes Dokument vorliegt. Zukünftig werden das vereinfachte und das genauere Nachweisverfahren in getrennten Normenteilen DIN 1053‐11 [3] und DIN 1053‐13 [4] geregelt. Von besonderer Bedeutung ist, dass mit dem genaueren Nachweisverfahren nunmehr auch die normenkonforme Bemessung von Elementmauerwerk aus großformatigen Steinen mit Überbindemaßen 0,2 ≤ ü/hSt < 0,4 möglich ist, welches bisher ausschließlich über Zulassungen geregelt war. Des Weiteren ist festzustellen, dass das vereinfachte und das genauere Nachweisverfahren einheitlich mit den Schnittgrößen auf Bemessungswertniveau arbeiten. Daher wird die Anwendbarkeit des genaueren Nachweisverfahrens deutlich vereinfacht, und die sich aus der wirklichkeitsnäheren Modellierung ergebenden Tragfähigkeitssteigerungen – insbesondere bei schlanken, knickgefährdeten Wänden – können praxisnah genutzt werden. Der vorliegende Beitrag beschreibt die wesentlichen Änderungen im genaueren Nachweisverfahren nach DIN 1053‐13 und vergleicht exemplarisch die Bemessungsergebnisse mit den nach DIN 1053‐1 und DIN 1053‐11 erzielbaren Tragfähigkeiten.
Zukünftige Bemessung von Mauerwerk – Überblick und vereinfachtes Verfahren
Authors: Jäger Wolfram
Published: September 2009

Nachdem die DIN 1053‐100 [1] im September 2006 auf die Musterliste der Technischen Baubestimmungen [2] gesetzt worden war, stand der Einführung in den einzelnen Bundesländern nichts mehr im Wege, so dass heute flächendeckend in der Bundesrepublik das semiprobabilistische Sicherheitskonzept angewendet werden kann (s. [3] bis [6]). Die DIN 1053‐100 bezieht sich jedoch nur auf die Bemessung, für Ausführung und Konstruktion galt weiterhin DIN 1053‐1:1996‐11 [7].

Im März diesen Jahres wurde nunmehr die vollständig überarbeitete DIN 1053‐1 als Entwurf veröffentlicht (s. [8] bis [11]). In ihr sind wieder Bemessung, Ausführung und Konstruktion auf gleichem zeitlichen Niveau vereinigt. Insbesondere im Bereich der Querkraftbeanspruchung von Mauerwerk hat es in den vergangenen Jahren erhebliche Aktivitäten gegeben, um das durch das Teil sicherheitskonzept eingetretene Defizit zu beseitigen. Weitere neuere Erkenntnisse und auch Notwendigkeiten sind hinzugekommen. Die Arbeit am Nationalen Anhang zu Eurocode 6 erforderte ebenfalls einen fundierten deutschen Standpunkt. Die europäischen Bestrebungen in der Mauerwerksnormung, die deutschen Erfahrungen und die neuen Erkenntnisse waren Anlass für eine völlige Neustrukturierung und Überarbeitung der deutschen Mauerwerksnorm für unbewehrtes Mauerwerk, die in diesem und dem anschließenden Beitrag vorgestellt wird.

Insbesondere im vereinfachten Verfahren ist einiges reduziert und bereinigt worden, allerdings ist auch Neues hinzugekommen. Im genaueren Verfahren ist i. W. der Querkraftnachweis neu. Weitere Dinge sind dem Erkenntnisstand angepasst worden.
Brandschutz im Mauerwerksbau
Authors: Schneider Ulrich
Published: September 2009

Der Mauerwerksbau ist eine der ältesten Bauweisen überhaupt und überzeugt durch hohe Dauerhaftigkeit und Sicherheit auch unter extremen Umgebungsbedingungen. In dem vorliegenden Beitrag wird zu Beginn diesbezüglich zurückgeblickt auf die römischen und mittelalterlichen Stadtbauweisen hinsichtlich ihres Verhaltens bei Bränden. Dominierend sind damals wie heute in jeder Hinsicht die Nichtbrennbarkeit und die hohe Festigkeit des Materials bei länger andauernden Temperatureinwirkungen.

Hinsichtlich der bauordnungsrechtlichen Anforderungen und deren Umsetzung hat es in den letzten Jahren Veränderungen gegeben, die im Zusammenhang mit einer Neuordnung der Gebäudeklassifizierung und dem europäischen Normungsprozess stehen. Bei der Einteilung der Gebäude ist eine neue Klasse mit einer Fußbodenhöhe bis 13 m über Oberkante Gelände eingeführt worden ([1] bis [3]). Gleichzeitig sind die brandschutztechnischen Anforderungen bis einschließlich dieser Gebäudeklasse mit der Feuerwiderstandsanforderung “hochfeuerhemmend” abgesenkt worden. Es ist damit auch der Einsatz brennbarer Baustoffe für tragende Konstruktionen, allerdings nur unter bestimmten Voraussetzungen, möglich, was das ehemals vorhandene hohe Sicherheitsniveau in diesem Bausegment abmindert. Durch den Einsatz von Mauerwerk ist es aber trotzdem möglich, den ursprünglich hohen Standard auch weiterhin beizubehalten. Neuere Entwicklungen in der Mauerwerksindustrie haben derzeit soweit geführt, dass die Wandmaterialien neben einem sehr guten Brandschutz auch ohne zusätzlichen bzw. mit sehr geringem zusätzlichen Wärmeschutz bereits Passivhausqualität erreichen und als High‐Tech‐Bauteile gelten.

Die bauordnungsrechtlichen Brandschutzanforderungen können sowohl mit Hilfe der deutschen als auch des europäischen Brandschutznormen umgesetzt werden (s. hierzu [4] bis [7]). Die europäischen Brandschutznormen enthalten einerseits ein System der Klassifizierung von Baustoffen und Bauteilen, jedoch in wesentlich differenzierterer Form als bisher in Deutschland üblich. Andererseits gestatten Bemessungsnormen für den Brandfall auch die rechnerische Nachweisführung, was dem Architekten bzw. dem Ingenieur mehr Freiheiten gibt. Diesbezüglich fehlen aber vor allem die zugehörigen Materialkennwerte in Abhängigkeit von den hohen Temperaturen, welche bei Bränden zu erwarten sind. Derartige Berechnungen sind u. a. auch dazu geeignet, die früheren Bauteilklassifizierungen nach den Brandschutzanforderungen des Eurocodes 6 neuerlich zu validieren.
Challenges in developing endpoints for type 1 diabetes intervention studies
Authors: Cernea Simona , Raz Itamar , Herold Kevan C. , Hirshberg Boaz , Roep Bart O. , Schatz Desmond A. , Fleming G. Alexander , Pozzilli Paolo , Little Randie , Schloot Nanette C. , Leslie R. David G. , Skyler Jay S. , Palmer Jerry P.
Published: September 2009

Development of efficient and safe intervention strategies for preserving and/or restoring endogenous insulin production in type 1 diabetes has encountered a wide range of challenges, including lack of standardized trial protocols and of consensus on appropriate efficacy endpoints. For the greatest part, difficulties resided in choosing the most suitable assay(s) and parameter(s) to assess the β‐cell function. It is now an accepted approach to evaluate endogenous insulin secretion by measuring C‐peptide levels (with highly sensitive and normalized measurement methods) in response to a physiologic stimulus (liquid mixed‐meal) under standardized conditions. Preventive interventions mandate the identification of well‐defined, reliable and validated mechanistic or immunological markers of efficacy that would correlate with (and predict) the clinical outcome. This has not been consistently achieved to date. However, it has been generally agreed that for preventive studies performed very early in the disease course (in subjects without signs of autoimmunity against β‐cells) development of two or more islet related autoantibodies could be employed as biomarkers of disease and thereafter, diagnostic criteria of diabetes serve as suitable endpoints.

This report summarizes the conclusions of the D‐Cure workshop of international experts held in Barcelona in April 2007 and the current recommendations and updates in the field. Copyright © 2009 John Wiley & Sons, Ltd.
The Versatile Alkylidene Moiety in Ruthenium Olefin Metathesis Catalysts (Eur. J. Inorg. Chem. 28/2009)
Authors: Diesendruck Charles E. , Tzur Eyal , Lemcoff N. Gabriel
Published: September 2009

The cover picture shows the development of the ruthenium alkylidene moiety from the first well‐defined ruthenium vinylalkylidene disclosed by Grubbs, through the first simple benzylidenes, alkylidenes, Fischer carbenes, vinylidenes, allenylidenes and indenylidenes, up to the functional chelated alkylidenes. Indeed, the development of this fragment has had a vital impact on the ruthenium‐catalyzed olefin metathesis reaction. Details are presented in the Microreview by N. G. Lemcoff et al. on p. 4185 ff. The authors gratefully acknowledge the Edmond J. Safra Foundation for their financial support.
Chitosan and marine phospholipids reduce matrix metalloproteinase activity in myeloma SP2 tumor‐bearing mice
Authors: Hossain Zakir , Fukunaga Kenji , Tanouchi Masatoshi , Takahashi Koretaro
Published: September 2009

An animal experiment was conducted to assess the antitumor effects of chitosan‐coated liposomes on myeloma SP2. The animal experimental groups designed for myeloma SP2 tumor‐bearing BALB/c mice were provided with five different drinks: (I) control (double‐distilled water); (II) squid phospholipid liposomes alone 1.0 mg/mL; (III) chitosan alone 5.0 mg/mL; (IV) squid phospholipid liposomes 1.0 mg/mL with chitosan 5.0 mg/mL in the form of a simple mixture; and (V) squid phospholipid liposomes 1.0 mg/mL coated with chitosan 5.0 mg/mL. At 20 days after implantation of the myeloma SP2 cells into mice, oral administration of the experimental drinks was provided for 35 days. There was significant suppression of tumor growth when chitosan and squid phospholipids were administered simultaneously in a simple mixture or as chitosan‐coated liposomes. Matrix metalloproteinase (MMP)‐2 and MMP‐9 activity was significantly less in the serum of mice that consumed chitosan‐coated liposomes than in control mice. We found that decreased tumor burden was related to MMP secretion. Therefore, chitosan‐coated marine phospholipid liposomes might be useful as potential agents for the treatment of myeloma SP2.
Novel 1,4,5,8‐Phenanthrenediquinones and Unusual Deoxygenation with Trimethylsilyl Iodide
Authors: Krohn Karsten , Aslan Abdulselam , Ahmed Ishtiaq , Pescitelli Gennaro , Funaioli Tiziana
Published: September 2009

Attempt for aryl methyl ether cleavage of 5,8‐dimethoxy‐1,4‐phenanthrenequinone (4) with boron trichloride or tribromide resulted in the halogenation of the quinone double bond to form 5a,b. Surprisingly, reaction of dimethyl ether 4 with trimethylsilyl iodide afforded the phenanthrenediquinone 6, whereas deoxygenation to 8 and 9 occurred by reaction of trimethylsilyl iodide with derivative 7. The phenanthrenediquinones 6 and 10 were obtained nearly quantitatively from 4 and 7 by using ceric ammonium nitrate as the oxidant. The cyclic voltammograms of the phenanthrenediquinones 6 and 10 were studied and rationalized by Hückel Molecular Orbital calculations. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Organocatalyzed α‐Oxyamination of Aldehydes Using Anodic Oxidation
Authors: Bui Nhat‐Nguyen , Ho Xuan‐Huong , Mho Sun‐il , Jang Hye‐Young
Published: September 2009

Electrochemical oxidation was performed during the organocatalyzed α‐oxyamination of aldehydes by using a one‐compartment electrolytic cell under galvanostatic conditions. In the presence of substoichiometric amounts of sec‐amines, the desired coupling products were formed in good yield. The asymmetric variant of the α‐oxyamination of aldehydes was examined by using chiral sec‐amines. Control experiments and cyclic voltammetry confirmed the key intermediate of this reaction to be the cationic radical of the enamine derived from the sec‐amine catalysts and aldehydes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Palladium‐Free Synthesis of Conjugated Enynes by Direct Olefination of Terminal Alkynes Using Vinyl Bromides
Authors: Liu Yunyun , Yang Jianguo , Bao Weiliang
Published: September 2009

A series of conjugated enynes were successfully synthesized by the direct copper‐catalyzed coupling reaction of vinyl bromides and alkynes. The reaction proceeds smoothly in DMF at 110 °C to give the corresponding products in good to excellent yields. The protocol is tolerant to a broad range of functional groups on the substrates. Moreover, the products were furnished as specific E isomers, as the stereochemistry of the vinyl bromides was retained. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Decision making under risk in Deal or No Deal
Authors: de Roos Nicolas , Sarafidis Yianis
Published: September 2009

We analyse the choices of 399 contestants in the Australian version of the television game show Deal or No Deal. We calculate risk aversion bounds for each contestant, revealing considerable heterogeneity. We then estimate a structural stochastic choice model that captures the dynamic decision problem faced by contestants. To address individual heterogeneity, we nest the dynamic problem within the settings of both a random effects and a random coefficients probit model. Our structural model produces plausible estimates of risk aversion, confirms the role of individual heterogeneity and suggests that a model of stochastic choice is indeed appropriate. We find mixed evidence of greater risk aversion by females. We also examine generalizations to expected utility theory, finding that the rank‐dependent utility model adds non‐negligible explanatory power and indicates optimism in probability weighting. Finally, we test, but are unable to confirm, the existence of an endowment effect for lotteries. Copyright © 2009 John Wiley & Sons, Ltd.
Scoring of collagen organization in healthy and diseased human dermis by multiphoton microscopy
Authors: Cicchi Riccardo , Kapsokalyvas Dimitrios , De Giorgi Vincenzo , Maio Vincenza , Van Wiechen Annelies , Massi Daniela , Lotti Torello , Pavone Francesco S.
Published: September 2009

We have used nonlinear imaging to evaluate collagen organization in connective tissue ex‐vivo samples. Image analysis methods were tested on healthy dermis, normal scars, and keloids. The evaluation of the second harmonic to autofluorescence aging index of dermis (SAAID) has allowed a first characterization of tissues by scoring the collagen/elastin content. Further analyses on collagen morphology in healthy dermis and keloids were performed by image‐pattern analysis of SHG images. The gray‐level co‐occurrence matrix (GLCM) analysis method has allowed classification of different tissues based on the evaluation of geometrical arrangement of collagen fibrillar bundles, whereas a pattern analysis of the FFT images has allowed the discrimination of different tissues based on the anisotropy of collagen fibers distribution. This multiple scoring method represents a promising tool to be extended to other collagen disorders, as well as to be used in in‐vivo skin‐imaging applications. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis of CdS‐ and ZnS‐modified bentonite nanoparticles and their applications to the degradation of eosin B
Authors: Ghiaci M. , Sedaghat M.E. , Aghaei H. , Gil A.
Published: September 2009

BACKGROUND: In the present study, nanocomposites of cadmium sulphide (CdS) and zinc sulphide (ZnS) on a bentonite have been prepared via an in‐situ precipitation route and their catalytic behaviour was evaluated in the degradation of eosin B.

RESULTS: It was found that the basal space of bentonite increased from 1.23 to 1.49 nm after CdS or ZnS nanoparticles were deposited on layers of the bentonite. The resulting CdS–bentonite and ZnS–bentonite nanocomposites can degrade eosin B from aqueous solution after 2 h under UV irradiation.

CONCLUSION: A soft method for in situ synthesis of monodispersed, CdS and ZnS nanoparticles, using a reverse micelle type procedure, is reported. The synthesized CdS‐ and ZnS–bentonite composites combined the adsorptive ability of bentonite and the catalytic degradation ability of CdS and ZnS to remove eosin B from its aqueous solution efficiently. Copyright © 2009 Society of Chemical Industry
Interaction of ‘toxic’ and ‘immunogenic’ A‐gliadin peptides with a membrane‐mimetic environment
Authors: Vilasi S. , Sirangelo I. , Irace G. , Caputo I. , Barone M. V. , Esposito C. , Ragone R.
Published: September 2009

Celiac disease (CD) is characterized by abnormally high concentrations of certain peptides in the small bowel. These peptides can be grouped in ‘toxic’ and ‘immunogenic’ classes, which elicit an innate immune response and an HLA‐mediated adaptive response, respectively. It is not clear on which molecular mechanisms responses to these different classes are based, but the 31–43 (P31–43) and the 56–68 (P56–68) A‐gliadin fragments are usually adopted as sequence representatives of toxic and immunogenic peptides, respectively. Here we report fluorescence experiments aiming to mimic the interaction of these peptides with the cell membrane surface by using sodium dodecyl sulphate (SDS) as a membrane‐mimetic medium. We show that P31–43 is able to bind SDS micelles in a way that resembles mixed micelle formation. On the other hand, no binding at all could be detected for P56–68. This different behaviour could be related to the paracellular or transcellular route through which gluten peptides may cross the intestinal epithelium, and open new insights into the pathogenetic mechanisms of CD. Copyright © 2009 John Wiley & Sons, Ltd.
On the relationships among work characteristics and learning‐related behavior: Does age matter?
Authors: de Lange Annet H. , Taris Toon W. , Jansen Paul , Kompier Michiel A. J. , Houtman Irene L. D. , Bongers Paulien M.
Published: September 2009

This 3‐wave longitudinal study examined (a) the causal direction of the relationships among psychosocial work characteristics (e.g., job demands, job control, and supervisor support) and indicators of learning‐related behavior (e.g., motivation to learn and active problem solving), and (b) whether these relationships differed across age, by comparing the results for young (≤30), middle‐aged (31–44) and older (≥45) workers. The results for the total sample revealed significant reciprocal causal relationships among job demands, job control, and learning‐related behavior. Furthermore, significant age differences were found in the level of the work characteristics and learning‐related behavior, as well as in the cross‐lagged relationships among the variables. Compared to earlier—predominantly cross‐sectional—results, the present study underlines the importance of taking a dynamic as well as a life‐span view on the relationships between work and learning‐related behavior. Copyright © 2009 John Wiley & Sons, Ltd.
Multilevel knowledge and team performance
Authors: Griffith Terri L. , Sawyer John E.
Published: September 2009

We examined team performance as it was affected by organizationally supported face‐to‐face and technology‐mediated knowledge practices. Guided by an information processing perspective, we demonstrate from a field study of over 250 teams within a global Fortune 100 technology company that team member participation in face‐to‐face and technology‐mediated knowledge practices (e.g., community of practice (CoP) meeting attendance and use of CoP‐related technologies, respectively), and team knowledge sharing practices are positively related to individual team member knowledge. We predicted that absorptive capacity would moderate tacit knowledge relationships with team performance, and that transactive memory would moderate explicit knowledge relationships with team performance. We found that the patterns of relationships differed depending on the measure of team performance. The predictions held for absorptive capacity by tacit knowledge on manager‐assessed performance, and for transactive memory by explicit knowledge on customer satisfaction. Additionally, there was a significant direct effect, with no moderation, of tacit knowledge on customer satisfaction. We highlight multilevel modeling for team research and argue for joint consideration of organizational and technology practices. Copyright © 2009 John Wiley & Sons, Ltd.
A long‐term vegetation history of the Mojave–Colorado desert ecotone at Joshua Tree National Park
Authors: Holmgren Camille A. , Betancourt Julio L. , Rylander Kate A.
Published: September 2009

Thirty‐eight dated packrat middens were collected from upper desert (930–1357 m) elevations within Joshua Tree National Park near the ecotone between the Mojave Desert and Colorado Desert, providing a 30 ka record of vegetation change with remarkably even coverage for the last 15 ka. This record indicates that vegetation was relatively stable, which may reflect the lack of invasion by extralocal species during the late glacial and the early establishment and persistence of many desert scrub elements. Many of the species found in the modern vegetation assemblages were present by the early Holocene, as indicated by increasing Sørenson's Similarity Index values. C4 grasses and summer‐flowering annuals arrived later at Joshua Tree National Park in the early Holocene, suggesting a delayed onset of warm‐season monsoonal precipitation compared to other Sonoran Desert and Chihuahuan Desert localities to the east, where summer rains and C4 grasses persisted through the last glacial–interglacial cycle. This would suggest that contemporary flow of monsoonal moisture into eastern California is secondary to the core processes of the North American Monsoon, which remained intact throughout the late Quaternary. In the Holocene, northward displacement of the jet stream, in both summer and winter, allowed migration of the subtropical ridge as far north as southern Idaho and the advection of monsoonal moisture both westward into eastern California and northward into the southern Great Basin and Colorado Plateau. Copyright © 2009 John Wiley & Sons, Ltd.
The last 100 000 years' palaeoenvironmental changes inferred from the diatom assemblages of core MD012404 from the Okinawa Trough, East China Sea
Authors: Chang Yuan‐Pin , Wang Wei‐Lung , Chen Min‐Te
Published: September 2009

The diatom assemblage records preserved in a sedimentary core MD012404 retrieved from the Okinawa Trough in the East China Sea (ECS) imply palaeoenvironmental changes of the last 100 ka. Our statistical analyses of diatom species abundance data indicate that the assemblages dominate open ocean and warm water, coastal water and freshwater masses in the ECS. These proxy species were used to infer the long‐term variation in surface hydrological conditions and palaeoclimate. Cycles of ca. 23 ka observed in the relative abundance of the tychopelagic species Paralia sulcata indicate that the increases in precipitation driven by solar insolation might have controlled the diatom assemblages in the ECS. The diatom records also indicate relatively low abundances of tropical, tychopelagic and freshwater species during millennial‐scale cold events such as the Younger Dryas and Heinrich events, which have been well expressed in the high‐latitude Northern Hemisphere climate. The floral patterns are interpreted as synchronous cooling and more saline sea surface conditions in the ECS caused by the enhanced Asian winter monsoon during the Northern Hemisphere cold events. The higher abundances of tropical species during deglaciation and the Holocene might have been linked to gradual increases in the inflow of the Kuroshio into the Okinawa Trough. The records also suggest a temporary reduction in tropical species from 5 to 3 ka, corresponding to the Pulleniatina Minimum Event during which the warm‐water planktic foraminifer Pulleniatina obliquiloculata was rare. Copyright © 2009 John Wiley & Sons, Ltd.
Were last glacial climate events simultaneous between Greenland and France? A quantitative comparison using non‐tuned chronologies
Authors: Blaauw Maarten , Wohlfarth Barbara , Christen J. Andrés , Ampel Linda , Veres Daniel , Hughen Konrad A. , Preusser Frank , Svensson Anders
Published: September 2009

Several large abrupt climate fluctuations during the last glacial have been recorded in Greenland ice cores and archives from other regions. Often these Dansgaard–Oeschger events are assumed to have been synchronous over wide areas, and then used as tie‐points to link chronologies between the proxy archives. However, it has not yet been tested independently whether or not these events were indeed synchronous over large areas. Here, we compare Dansgaard–Oeschger‐type events in a well‐dated record from southeastern France with those in Greenland ice cores. Instead of assuming simultaneous climate events between both archives, we keep their age models independent. Even these well‐dated archives possess large chronological uncertainties that prevent us from inferring synchronous climate events at decadal to multi‐centennial time scales. If possible, comparisons between proxy archives should be based on independent, non‐tuned time‐scales. Copyright © 2009 John Wiley & Sons, Ltd.
Fire, climate and the origins of agriculture: micro‐charcoal records of biomass burning during the last glacial–interglacial transition in Southwest Asia
Authors: Turner Rebecca , Roberts Neil , Eastwood Warren J. , Jenkins Emma , Rosen Arlene
Published: September 2009

This study investigates changes in climate, vegetation, wildfire and human activity in Southwest Asia during the transition to Neolithic agriculture between ca. 16 and ca. 9 ka. In order to trace the fire history of this region, we use microscopic charcoal from lake sediment sequences, and present two new records: one from south central Turkey (Akgöl) and the other from the southern Levant (Hula). These are interpreted primarily as the result of regional‐scale fire events, with the exception of a single large event ca. 13 ka at Akgöl, which phytolith analysis shows was the result of burning of the local marsh vegetation. Comparison between these and other regional micro‐charcoal, stable isotope and pollen records shows that wildfires were least frequent when the climate was cold and dry (glacial, Lateglacial Stadial) and the vegetation dominated by chenopod–Artemisia steppe, and that they became more frequent and/or bigger at times of warmer, wetter but seasonally dry climate (Lateglacial Interstadial, early Holocene). Warmer and wetter climates caused an increase in biomass availability, with woody matter appearing to provide the main fuel source in sites from the Levant, while grass fires predominated in the interior uplands of Anatolia. Southwest Asia's grasslands reached their greatest extent during the early Holocene, and they were maintained by dry‐season burning that helped to delay the spread of woodland by up to 3 ka, at the same time as Neolithic settlement became established across this grass parkland landscape. Although climatic changes appear to have acted as the principal ‘pacemaker’ for fire activity through the last glacial–interglacial climatic transition (LGIT), human actions may have amplified shifts in biomass burning. Fire regimes therefore changed markedly during this time period, and both influenced, and were influenced by, the cultural‐economic transition from hunter‐foraging to agriculture and village life. Copyright © 2009 John Wiley & Sons, Ltd.
Depolarization effects in tip‐enhanced Raman spectroscopy
Authors: Merlen A. , Valmalette J. C. , Gucciardi P. G. , Lamy de la Chapelle M. , Frigout A. , Ossikovski R.
Published: September 2009

Tip‐enhanced Raman spectroscopy has proven to be a promising technique for stress/strain mapping of silicon‐based semiconductor devices on the nanometer scale. Field enhancement factors of up to 104 have been reported and a spatial resolution down to 20 nm has been claimed through exploiting far‐field suppression techniques based on an appropriate choice of the excitation/detection polarization states. In this paper, we show that depolarization of light due to scattering from the tip plays a key role in the selective enhancement of the one‐phonon optical mode peak at 520 cm−1 with respect to the two‐phonon ones. The spatial confinement of the selective enhancement has been studied by means of approach curves, and its dependence on the excitation wavelength and power further explored. Conclusions on the physical nature of the enhancement (depolarization‐ or plasmonic‐based) are presented. Copyright © 2009 John Wiley & Sons, Ltd.
Tip‐enhanced Raman spectroscopy of carbon nanotubes
Authors: Cançado Luiz Gustavo , Hartschuh Achim , Novotny Lukas
Published: September 2009

This paper presents an overview on the principles of tip‐enhanced Raman spectroscopy (TERS). The technique can be used to record Raman images of carbon nanotubes with high spatial resolution. The high resolution is made possible by local enhancement of the incident and scattered fields. The paper also presents some advances on the science of carbon nanotubes generated by TERS, including the observation of local defects, chirality changes, and dopants. Copyright © 2009 John Wiley & Sons, Ltd.
Raman microscopy of the mixite mineral BiCu6(AsO4)3(OH)6·3H2O from the Czech Republic
Authors: Frost Ray L. , Čejka Jiří , Sejkora Jiří , Plášil Jakub , Bahfenne Silmarilly , Palmer Sara J.
Published: September 2009

Raman microscopy of the mixite mineral BiCu6(AsO4)3(OH)6·3H2O from Jáchymov and from Smrkovec (both Czech Republic) has been used to study their molecular structure. The presence of (AsO4)3−, (AsO3OH)2−, (PO4)3− and (PO3OH)2− units, as well as molecular water and hydroxyl ions, was inferred. OH···O hydrogen bond lengths were calculated from the Raman and infrared spectra using Libowitzky's empirical relation. Small differences in the Raman spectra between both samples were observed and attributed to compositional and hydrogen‐bonding network differences. Copyright © 2009 John Wiley & Sons, Ltd.
Surface‐enhanced Raman spectroscopy (SERS) on silver colloids for the identification of ancient textile dyes: Tyrian purple and madder
Authors: Bruni Silvia , Guglielmi Vittoria , Pozzi Federica
Published: September 2009

Surface‐enhanced Raman spectroscopy (SERS) was used for the identification of natural organic dyes belonging to indigoid and anthraquinone classes in archeological samples, and good agreement with the corresponding reference commercial materials was found. Special attention was paid to the well‐known problem of anomalous bands that arise sometimes in the SERS spectra on colloids: as suggested in the literature, this problem could be reduced by the use of poly‐L‐lysine and ascorbic acid as aggregating agents, but we observed that also the addition first of the analyte and subsequently of suitable electrolytes to the colloid in an inverted order compared to the most widely used method can be of help in limiting the intensity of such spurious bands. This procedure allowed us to obtain, for the first time, the SERS spectra of both modern and ancient Tyrian purple and to solve a specific problem observed in the analysis of archeological wool samples dyed with madder lake, i.e. the competition in the SERS response between the dye and other compounds possibly deriving from the degradation of the peptide chain during the hydrolysis treatment during the extraction of the dye from the wool fiber. Copyright © 2009 John Wiley & Sons, Ltd.
Destruction of the short‐range disorder due to erbium doping in Pb0.8La0.2TiO3films
Authors: Huang Tung‐Ching , Hsieh Wen‐Feng
Published: September 2009

We show the destruction of a displacement of Ti in the short‐range structure by observing the disappearance of emission and Raman signals when the Er3+ concentration exceeds 7 mol% in sol–gel‐derived Pb0.8La0.2TiO3 polycrystalline films. It is believed that there always exists disorder due to displacement of B ions in the skeleton of BO6 in perovskite ABO3 materials. This disorder due to the displacement of Ti ions breaks the center of symmetry to activate emission of rare‐earth ions such as Er3+ and Raman modes of perovskites. We found that the breaking of symmetry can be diminished by introducing more Er3+ ions. Copyright © 2009 John Wiley & Sons, Ltd.
Yield and baking quality of winter wheat cultivars in different farming systems of the DOK long‐term trial
Authors: Hildermann Isabell , Thommen Andreas , Dubois David , Boller Thomas , Wiemken Andres , Mäder Paul
Published: September 2009

BACKGROUND: A challenge in wheat (Triticum aestivum L.) breeding for organic farming is to provide high‐yielding cultivars with appropriate baking qualities under the limiting conditions of organic fertiliser input and without the use of pesticides. Cultivars are usually tested on organic and conventional farms. However, field properties may differ owing to spatial variations of soils and microclimate heterogeneity. In this study, old, organically bred and conventionally bred cultivars were tested in organic and conventional farming systems of the DOK long‐term system comparison trial.

RESULTS: Effects of cultivars and systems on yield and quality parameters were statistically significant. Genotype × system interactions were generally not observed. Grain yield across all cultivars increased from 4.2 Mg ha−1 under organic conditions up to 6.8 Mg ha−1 under conventional conditions, with protein contents of 90 and 117 g kg−1 respectively. Conventionally bred cultivars yielded significantly more under conventional conditions than organically bred cultivars, whereas neither organically nor conventionally bred cultivars performed better under organic conditions.

CONCLUSION: Breeding for yield was successful, but only under high‐input conditions, where these successes were accompanied by rising inputs of external resources. The results of this study suggest that cultivar testing in long‐term system comparisons can complement standard on‐farm testing. Copyright © 2009 Society of Chemical Industry
Optimisation of pressurised liquid extraction for the determination of monosaccharides and polyalcohols in woods used in wine aging
Authors: Alañón Maria Elena , Ruiz‐Matute Ana Isabel , Martínez‐Castro Isabel , Díaz‐Maroto Maria Consuelo , Pérez‐Coello Maria Soledad
Published: September 2009

BACKGROUND: The carbohydrate profile of woods used to age wines and spirits is largely unstudied in spite of its possible influence on the quality of aged beverages. This experiment evaluated the feasibility of employing pressurised liquid extraction to isolate monosaccharides and polyalcohols from woods used in aging, yielding a reliable analytical extraction method for characterising these compounds. Various solvents were tested and the extraction procedure was optimised by a three‐level factorial experimental design based on two main factors: extraction temperature and extraction time. The total extraction yield of target compounds was taken as response variable, and model parameters were estimated by multiple linear regression.

RESULTS: Methanol was best at extracting the target compounds and hence was selected as solvent. Temperature was the most important factor in the extraction process, and the optimal extraction conditions were 90 °C for 15 min.

CONCLUSION: Pressurised liquid extraction proved to be a highly suitable and powerful technique for extracting the monosaccharides and polyalcohols from wood samples. Analysis of the carbohydrate profile of the woods revealed differences among samples of different species and types of wood. Copyright © 2009 Society of Chemical Industry
Comparison of the characterisation of the fruit‐like aroma of Teucrium flavum L. subsp flavum by hydrodistillation and solid‐phase micro‐extraction
Authors: Maggi Filippo , Bílek Tomas , Cristalli Gloria , Papa Fabrizio , Sagratini Gianni , Vittori Sauro
Published: September 2009

BACKGROUND: Teucrium species (Lamiaceae) are interesting for the food industry since many of them are used in the preparation of flavoured wines and beers, herbal teas, bitters and liqueurs. On this basis, the analysis of the aroma components of Teucrium flavum L. subsp. flavum growing in central Italy was carried out by means of both hydrodistillation (HD) and headspace solid‐phase micro‐extraction (HS‐SPME), coupled with GC/FID and GC/MS.

RESULTS: A total of 102 components were identified in the essential oils, representing 99.0‐99.3% of the total oils. Sesquiterpenes hydrocarbons constituted the major fraction (48.5–49.4%), with the apple‐like flavour (Z,E)‐α‐farnesene being the major component. HS‐SPME allowed the analysis of the volatiles not only emitted by specific plant parts, but also by different parts within a single flower: flower calyx afforded the highest contribution, in terms of volatiles, to the aroma of the plant.

CONCLUSION: The chemical profile of the volatile fraction obtained by HD and HS‐SPME, demonstrated the plant fruit‐like aroma, confirming the usefulness for flavouring wines, bitters and other kind of beverages, and also suggested other applications, as aroma and taste enhancer in food processing. In particular, SPME resulted in a very useful technique, which permits a choice between the part of the plant which has the highest concentration of a specific fragrance, and therefore establishes the best way of sampling during industrial applications of aromatic plants. Copyright © 2009 Society of Chemical Industry
Smart Laser Welding Heads Provide Excellent Quality
Authors: Andreev Andrey
Published: September 2009

Equipped with pulsed Nd:YAG lasers, single‐mode fibre lasers and “conventional” Co2 lasers, the BBW Lasertechnik GmbH in Prutting, upper Bavaria, tackles cutting, drilling, inscribing and welding tasks. BBW mainly processes sophisticated small components in stainless steel, spring band steel, steel and aluminium. a visitor to the works will see complete assembly lines on which highly complex and often safety‐relevant parts are processed for well‐known companies. Quality monitoring systems, laser welding and cutting heads by Precitec KG contribute to the company's cost‐effective production, which runs at 250 parts per week or up to 300,000 per year.
Understanding Materials Processing Lasers
Authors: Woods Stuart
Published: September 2009

A decade ago, flowing gas CO2 lasers dominated the market for materials processing applications, such as cutting, welding and marking of metals and organics. However, over the past few years, new laser technologies have emerged that give the materials processor more options in choosing a laser source. Specifically these developments include the introduction of higher power sealed CO2 lasers, the advent of fiber lasers, and improvements in the brightness of direct diode laser systems. The result is that choosing the right laser for a specific application is now a more complex task than in the past. This article reviews the technology and capabilities of all these laser types and provides guidance on identifying the optimal source for a specific need.
Laser‐Based Polymer Welding in Medical Device Manufacturing
Authors: Neukum Jörg
Published: September 2009

Polymer welding in medical device manufacturing has special requirements as related to the colors of the materials, the process control and the documentation of the process parameters. The usage of laser‐based plastics joining brings in some aspects which make this joining method for particular applications advantageous compared to classical plastics joining methods like ultrasonic or heat‐stamp. Some of the advantages of laser welding of polymers are

·its excellent welding quality

·the protected welding zone (inside welding)

·the clean surfaces (no particles)

·the high optical quality of the seam

·the minimal thermal load to the work piece

·easy designs (flat surfaces e.g.)

·the contact‐free welding process (no deterioration of the welding quality)

·the online closed‐loop process control and documentation.

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Laser‐sintering in the Aerospace Industry is on the Rise
Authors: Behrendt Udo
Published: September 2009

Today's aerospace suppliers are operating in a highly competitive market that is characterized by an increasing number of customized and more complex parts and products, yet decreasing production quantities. this cannot be handled with normal serial production characterized by a high number of identical products. to meet these requirements, the industry has to break new grounds in part production. In addition, we see global markets facing ever shortening product life cycles and product variety on the rise which makes spare part supply increasingly difficult as well. Small lot sizes tend to make the use of traditional manufacturing technologies a too cost‐intensive investment. Manufacturing methods that are based on economies of scale are no longer in a position to meet these challenges. In sum, the prerequisites for efficient manufacturing today are thus high‐performance materials yet creating cost savings.
Slow and fast light: basic concepts and recent advancements based on nonlinear wave‐mixing processes
Authors: Bortolozzo U. , Residori S. , Huignard J.‐P. Pierre
Published: September 2009

After a review of the basic concepts of slow and fast light, recent advancements based on nonlinear wave‐mixing processes are described. As a nonlinear medium, the authors focus on a liquid crystal light valve showing that it allows obtaining a large control of the group delay, with a maximum fractional delay of 1, and a deceleration of light pulses down to group velocities as small as 0.2 mm/s. A theoretical model accompanies the observations and accounts for them in the general framework of two‐wave mixing in the light valve. At the end, a high‐sensitivity interferometer is presented as an example of slow light applications.
Hydrogen generation from photoelectrochemical water splitting based on nanomaterials
Authors: Li Y. , Zhang J.Z.
Published: September 2009

Hydrogen is potentially one of the most attractive and environmentally friendly fuels for energy applications. Safe and efficient generation, storage, and utilization of hydrogen present major challenges in its widespread use. Hydrogen generation from water splitting represents a holy grail in energy science and technology, as water is the most abundant hydrogen source on the Earth. Among different methods, hydrogen generation from photoelectrochemical (PEC) water splitting using semiconductors as photoelectrodes is one of the most scalable and cost‐effective approaches. Compared to bulk materials, nanostructured semiconductors offer potential advantages in PEC application due to their large surface area and size‐dependent properties, such as increased absorption coefficient, increased band‐gap energy, and reduced carrier‐scattering rate. This article provides a brief overview of some recent research activities in the area of hydrogen generation from PEC water splitting based on nanostructured semiconductor materials, with a particular emphasis on metal oxides. Both scientific and technical issues are critically analyzed and reviewed.
Poly(ethylene glycol)‐block‐Poly(glycidyl methacrylate) with Oligoamine Side Chains as Efficient Gene Vectors
Authors: Ma Ming , Li Feng , Chen Fu‐jie , Cheng Si‐xue , Zhuo Ren‐xi
Published: September 2009

Well‐defined diblock copolymers, poly(ethylene glycol)‐block‐poly(glycidyl methacrylate)s (PEG‐b‐PGMAs), with different poly(glycidyl methacrylate) (PGMA) chains, were prepared via atom transfer radical polymerization (ATRP) from the same macromolecular initiator 2‐bromoisobutyryl‐terminated poly(ethylene glycol) (PEG). Ethyldiamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), and polyethyleneimine (PEI) with an $\overline M _{\rm w}$ of 400 (PEI400) were used to decorate PEG‐b‐PGMAs to get the cationic polymers PEG‐b‐PGMA‐ oligoamines. These cationic polymers possessed high buffer capability and could condense plasmid DNA (pDNA) into nanoscaled complexes of 125–530 nm. These complexes showed the positive zeta potential of 20–35 mV at N/P ratios of 10–50. Most of them exhibited very low cytotoxicity and good transfection efficiency in 293T cells. The presence of the serum medium did not decrease the transfection efficiency due to the steric stabilization of the PEG chains.

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Influence of the Copolymer Content on the Miscibility, Phase Behaviour and Morphology of a DGEBA/Polystyrene/Styrene‐co‐Maleic Anhydride Ternary Blend
Authors: García‐Lopera Rosa , Figueruelo Juan E. , Monzó Isidro S. , Abad Concepción , Campos Agustín
Published: September 2009

The miscibility, phase behaviour and morphology of ternary systems, formed by a DGEBA‐based epoxy resin, polystyrene (PS) and styrene‐co‐maleic anhydride (SMA) copolymers have been investigated through phase diagrams. The analysis has been done in the absence and in the presence of 4,4′‐methylene bis(2,6‐diethyl aniline) (MDEA) as curing agent. In both cases, the influence of the copolymer content on blend compatibility, has been discussed. The results show that miscibility is enhanced by the presence of SMA copolymer in the blend and as the MA content in the copolymer is increased (from 7 to 14 wt.‐%), due to specific H‐bonding interactions between the H‐donor hydroxyl groups on the epoxy resin and the H‐acceptor carbonyl groups in the copolymer. Experimental results have been fitted with a thermodynamic model based on the classical Flory–Huggins lattice theory, by using interaction parameters, depending both on temperature and composition. The presence of MDEA cross‐linking agent, yielded microphase‐separated materials. The morphological evolution of this epoxy networks, with and without PS + SMA thermoplastic modifier, has been examined by scanning electron microscopy (SEM).

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Preparation, characterization and application of zwitterionic polymers and membranes: current developments and perspective
Authors: Xuan Fengqin , Liu Junsheng
Published: September 2009

Because of their unique pendant‐side chain structures and excellent properties, zwitterionic polymers and membranes, especially zwitterionic hybrids, have attracted increasing interest in recent years. Presently, they can be potentially applied in such fields as nonlinear optical systems, ionic conduction, biomedical processing and chemical separation. In view of their significance to academia and industrial processes, this review gives a brief summary of current developments in the preparation, characterization and potential application of zwitterionic polymers and membranes. Novel approaches to prepare zwitterionic hybrids are highlighted. The present state and future perspective are also discussed. Hopefully, this review can promote the understanding of zwitterionic hybrid polymers and membranes. Copyright © 2009 Society of Chemical Industry
Elucidation of the percutaneous absorption of chromium compounds by functional proteomics
Authors: Pan Tai‐Long , Wang Pei‐Wen , Huang Chun‐Ming , Chen Chih‐Chieh , Fang Jia‐You
Published: September 2009

Chromium compounds are known to be associated with cytotoxicity and carcinogenicity when applied via a skin route. The aim of this study was to evaluate the skin permeability and toxicological profiles of four chromium species. Chromium permeation across the skin, as determined by an in vitro Franz cell, decreased in the order of sodium chromate>potassium chromate>potassium dichromate>chromium nitrate. The uptake of chromium species within the skin generally showed a contrary trend to the results of permeation, although differences among the various compounds were not large. Levels of in vivo skin deposition of the four compounds showed no statistically significant differences. Potassium chromate produced the greatest disruption of the skin structure as determined by HE staining, followed in order by sodium chromate, potassium dichromate, and chromium nitrate. This indicates that hexavalent chromium elicited greater toxicity to the skin compared to trivalent chromium. A similar result was observed for the viability of skin fibroblasts. To improve our understanding of the molecular mechanisms leading to functional changes in proteins, proteomic tools, including 2‐DE and MS techniques combined with sequence database correlations, were applied to identify target proteins altered by pathologic states. Eight protein spots, corresponding to cutaneous enzymes involved in energy metabolism and chaperon proteins, which were identified and discussed in this study, were associated with skin cytotoxicity, immunity, and carcinogenesis. In addition, functional proteomics of skin tissues may provide a promising tool for developing therapeutic strategies and can serve as the basis for further research.