bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractSeveral 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

AbstractThis 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

AbstractTip‐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

AbstractThis 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

AbstractRaman 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

AbstractSurface‐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

AbstractWe 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

AbstractBACKGROUND: 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

AbstractBACKGROUND: 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

AbstractBACKGROUND: 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

AbstractEquipped 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

AbstractA 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

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

AbstractToday'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

AbstractAfter 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

AbstractHydrogen 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

AbstractWell‐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.magnified image
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

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

AbstractBecause 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