bluuebunny/crossref_metadata_2025_split huggingface dataset:
Luftverkehr und Klima. Atmosphärenforschung
Authors: Schumann, Ulrich 
Published: April 2008

AbstractDer globale Luftverkehr hat zum bisherigen Klimawandel nicht nur durch Ausstoß von Kohlendioxid, sondern auch durch Zusatzeffekte aus Stickoxiden, Kondensstreifen und Veränderungen der Bewölkung beigetragen. An der Gesamtheit der von Menschen verursachten Klimaänderung ist der Luftverkehr bisher mit etwa 3 % (2 bis 8 %) beteiligt. Der Anteil der Zusatzeffekte hängt vom Wachstum des Flugverkehrs und der betrachten Zeitspanne in der Zukunft ab und kann nicht mit einem konstanten Faktor bewertet werden. Bei raschem Verkehrswachstum sind die Zusatzeffekte groß, bei langsamerem Wachstum und über lange Zeiträume dominiert das ausgestoßene Kohlendioxid die Klimawirkung des Luftverkehrs.
Solarzellen nach biologischem Vorbild?
Authors: Wörmke Stephan , Mackowski Sebastian , Scheer Hugo , Bräuchle Christoph 
Published: April 2008

AbstractForscher der LMU München haben gezeigt, dass sich mit Hilfe von Silbernanoteilchen die Effizienz von Lichtsammelkomplexen enorm steigern lässt. Da es sich hierbei um die zentralen Funktionsträger für das Einsammeln von Licht bei der Photosynthese handelt, könnte diese Entdeckung bedeutsam für die Entwicklung neuartiger Hybrid‐Solarzellen sein.
Teilchenbeschuss aus dem All
Authors: Heering Peter 
Published: April 2008

AbstractAnfang des 20. Jahrhunderts wies der österreichische Physiker Victor Hess die von ihm so genannte Höhenstrahlung nach. Allerdings waren seine Ergebnisse zunächst umstritten. Erst mit den Untersuchungen der Forschungsgruppe Robert Millikans, der für diese Strahlung den Begriff cosmic rays etablierte, wurde dieses Phänomen allgemein akzeptiert. Bis heute spielt die Untersuchung der Höhenstrahlung eine wesentliche Rolle in der physikalischen Grundlagenforschung.
Enzymatischer Proteinleim
Authors: Vilgis Thomas 
Published: April 2008

Abstract“Zu schade zum Wegwerfen” ist der Leitsatz in vielen Küchen und Lebensmittelunternehmen. Das gilt beispielsweise für hochwertige Fleischabschnitte, die in Würsten oder Pasteten verarbeitet werden. Derartige Fleischtrümmer können mit biologischer Klebetechnik wieder in Form gebracht werden. Das Enzym Transglutaminase leistet dabei katalytische Dienste und verklebt Fleischstücke, indem es deren Proteine permanent vernetzt. Wie funktioniert und was nützt uns das?
Identification of peptidases in Nicotiana tabacum leaf intercellular fluid
Authors: Delannoy Mélanie , Alves Georges , Vertommen Didier , Ma Julian , Boutry Marc , Navarre Catherine 
Published: April 2008

AbstractPeptidases in the extracellular space might affect the integrity of recombinant proteins expressed in, and secreted from, plant cells. To identify extracellular peptidases, we recovered the leaf intercellular fluid from Nicotiana tabacum plants by an infiltration–centrifugation method. The activity of various peptidases was detected by an in vitro assay in the presence of specific inhibitors, using BSA and human serum γ‐globulin as substrates. Peptidases were detected by 1‐ and 2‐D zymography in a polyacrylamide gel containing gelatin as substrate. Proteolytic activity was observed over a wide range of molecular masses equal to, or higher than, 45 kDa. To identify the peptidases, the extracellular proteins were digested with trypsin and analyzed by LC and MS. Seventeen peptides showing identity or similarity to predicted plant aspartic, cysteine, and serine peptidases have been identified. The extracellular localization of a cysteine peptidase aleurain homolog was also shown.
Novel approaches to predict the retention of histidine‐containing peptides in immobilized metal‐affinity chromatography
Authors: Du Hongying , Zhang Xiaoyun , Wang Jie , Yao Xiaojun , Hu Zhide 
Published: April 2008

AbstractThe new method lazy learning method–local lazy regression (LLR) was first used to model the quantitative structure–retention relationship (QSRR) for predicting and explaining the retention behaviors of peptides in the nickel column in immobilized metal‐affinity chromatography (IMAC). The best multilinear regression (BMLR) method implemented in the CODESSA was used to select the most appropriate molecular descriptors from a large set and build a linear regression model. Based on the selected five descriptors, another two approaches, projection pursuit regression (PPR) and LLR were used to build more accurate QSRR models. The coefficients of determination (R2) of the best model developed based on LLR were 0.9446 and 0.9252 for the training set and the test set, respectively. By comparison, it was proved that the novel local learning method LLR was a very promising tool for QSRR modeling with excellent predictive capability for the prediction of imidazole concentration (IMC) values of histidine‐containing peptides in IMAC. It could be used in other chromatography research fields and that should facilitate the design and purification of peptides and proteins.
Déjà vu in proteomics. A hit parade of repeatedly identified differentially expressed proteins
Authors: Petrak Jiri , Ivanek Robert , Toman Ondrej , Cmejla Radek , Cmejlova Jana , Vyoral Daniel , Zivny Jan , Vulpe Christopher D. 
Published: April 2008

AbstractAfter reading many 2‐DE‐based articles featuring lists of the differentially expressed proteins, one starts experiencing a disturbing déjà vu. The same proteins seem to predominate regardless of the experiment, tissue or species. To quantify the occurrence of individual differentially expressed proteins in 2‐DE experiment reports, we compiled the identities of differentially expressed proteins identified in human, mouse, and rat tissues published in three recent volumes of Proteomics and calculated the appearance of the most predominant proteins in the dataset. The most frequently identified protein is a highly abundant glycolytic enzyme enolase 1, differentially expressed in nearly every third experiment on both human and rodent tissues. Heat‐shock protein 27 (HSP27) and heat‐shock protein 60 (HSP60) were differentially expressed in about 30 percent of human and rodent samples, respectively. Considering protein families as units, keratins and peroxiredoxins are the most frequently identified molecules, with at least one member of the group being differentially expressed in about 40 percent of all experiments. We suggest that the frequent identification of these proteins must be considered in the interpretation of any 2‐DE studies. We consider if these commonly observed changes represent common cellular stress responses or are a reflection of the technical limitations of 2‐DE.
Phosphorylation of measles virus nucleoprotein upregulates the transcriptional activity of minigenomic RNA
Authors: Hagiwara Kyoji , Sato Hiroki , Inoue Yoshihisa , Watanabe Akira , Yoneda Misako , Ikeda Fusako , Fujita Kentaro , Fukuda Hiroyuki , Takamura Chizuko , Kozuka‐Hata Hiroko , Oyama Masaaki , Sugano Sumio , Ohmi Shinobu , Kai Chieko 
Published: April 2008

AbstractWe report the first identification of phosphorylation sites of the nucleoprotein (N) of the family Paramyxoviridae. The N protein is known to be the most abundant protein in infected cells; it constructs the N–RNA complex (nucleocapsid) and supports transcription and replication of viral genomic RNA. To determine the role of phosphorylation of the N protein, we expressed the N protein of the HL strain of measles virus (MV) in mammalian cells and purified the nucleocapsid. After separation of the C‐terminal region from the core region, phosphorylated amino acids were assayed using MALDI‐TOF/TOF and ESI‐Q‐TOF MS analyses. Two amino acids, S479 and S510, were shown to be phosphorylated by both methods of analysis. Metabolic labeling of the N protein with 32P demonstrated that these two sites are the major phosphorylated sites within the MV‐N protein. In transcriptional analysis using negative‐strand minigenomic RNA containing the ORF of the luciferase gene, mutants of each phosphorylation site showed approximately 80% reduction in luciferase activity compared with the wild‐type N, suggesting that the phosphorylation of N protein is important in the activation of the transcription of viral mRNA and/or replication of the genome in vivo.
Spectroscopic study of mono‐ and bis(styryl) dyes of the pyridinium series containing azathiacrown ether residue
Authors: Tulyakova E. V. , Fedorova O. A. , Fedorov Yu. V. , Jonusauskas G. , Anisimov A. V. 
Published: April 2008

AbstractPhenylazathiacrown ether monostyryl and bis(styryl) dyes were synthesized and their complex forming ability was evaluated in acetonitrile by absorption and fluorescence spectroscopy. It was found that dyes are sensitive to the presence of H+ and Hg2+, Ag+, Cu2+ cations. The most stable complexes were formed with mercury. Stability constants and UV–Vis spectra of complexes defined stoichiometry were determined with the use of HYPERQUAD program. Evidence was given for the occurrence of two stoichiometries: LM and LM2. The pronounced optical response on complex formation was found both in absorption and emission spectra that could be used for optical detection of cations. Copyright © 2008 John Wiley & Sons, Ltd.
An exploratory study to investigate possible simple descriptors in order to predict relative activity of antiepileptic enaminones
Authors: Martinez J. C. Garro , Andrada M. F. , Estrada M. R. , Castro E. A. , Zamarbide G. N. , Mucsi Z. , Csizmadia I. G. 
Published: April 2008

AbstractA general structure, substituent and activity relationship of the following type has been fitted to the available ED50 values of cyclic enaminone antiepileptic compounds: ${\rm ED}_{50} = f\left[ {{\rm structure,}\;{\rm substituent}} \right] = f[d, \sigma]$. In this relationship ‘structure’ was quantified by d, the distance measured between the carbonyl oxygen and the first atom of the aromatic ring. The ‘substituent’ was quantified by Hammett substituent constant: (σ). With the aid of the above function of two independent variables, a new molecular structure was predicted by extrapolation that has shown about two orders of magnitude greater activity than the most active molecule in the original set with measured ED50 values. Copyright © 2008 John Wiley & Sons, Ltd.
Quantitative approach to evaluate the intramolecular interaction of the appointed and unlinked groups or nonhydrogen atoms within organic compounds
Authors: Zhang Chaoyang 
Published: April 2008

AbstractThis paper reported a new approach to quantitatively evaluate the interaction of the appointed and indirectly linked groups or nonhydrogen atoms in molecules by designing unique isodesmic reactions, calculating their energy changes, and getting so‐called interaction energy (Ei). The consistency of the sign and amount of Ei with the common qualitative descriptions on some intramolecular effects confirmed the validity of the new method. Two applications of this method to halogenated methane and ethane, and nitro compounds showed: (1) for any group of molecules with the same skeleton, Ei of all substitution groups or nonhydrogen atoms can be used to compare their molecular stabilities; (2) for the appointed groups in different molecules, Ei of them can reveal the nature (attraction or repulsion) and the strength of their interaction. All these indicated that Ei is a useful tool to reflect the intramolecular interaction of appointed and unlinked groups or nonhydrogen atoms. Copyright © 2008 John Wiley & Sons, Ltd.
Charge transport and single‐electron effects in nanoscale systems
Authors: Thijssen J. M. , Van der Zant H. S. J. 
Published: April 2008

AbstractIn this review, we consider single‐electron effects in transport through nanoscale devices. These effects are ubiquitous in quantum dot physics, but in recent years their occurrence in molecular transport has triggered important new research efforts. In this case, the experimental results show a rich variety of features which make it possible to extract a wealth of information about the physics of these structures. We shall show that most of this information can be extracted in the case where the coupling of the active region to the leads is weak. However, between the strong and weak coupling regimes, that is, at intermediate coupling, we can observe the richest behaviour. We shall very briefly outline the physics of different transport processes through three‐terminal devices and then focus on the single‐electron effects. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical spectroscopy of single‐walledcarbon nanotubes: From excitonic effects towards control of the radiative lifetime
Authors: Pomraenke Robert , Vasa Parinda , Lienau Christoph 
Published: April 2008

AbstractWe have recently studied excitonic effects on the optical properties of single‐walled carbon nanotubes by means of two‐photon spectroscopy and time‐resolved photoluminescence spectroscopy. For nanotubes with diameters between 6.8 Å and 9.0 Å, the two‐photon spectra give evidence for large binding energies between 300 meV to 400 meV. Theoretical simulations of these spectra indicate that the lowest energy exciton state in nanotubes is an optically dark exciton, which has profound implications on the luminescence yield and exciton dynamics in single‐walled nanotubes. Indeed, time‐resolved photoluminescence measurements of individual nanotubes reveal low quantum yields and rather short exciton lifetimes ranging from 10 ps to 200 ps, which are affected by exciton relaxation between bright and dark states and non‐radiative exciton recombination. These results suggest that a control of the radiative lifetime of nanotube excitons may be a viable strategy for enhancing their luminescence yield. Here, we propose that exciton‐coupling to surface plasmon polaritons in metallic nanostructures may result in a substantial enhancement of the radiative exciton decay rate. Two‐photon luminescence excitation spectra of single‐walled carbon nanotubes. The luminescence intensity is plotted as a function of excitation and detection wavelength. The various two‐photon resonances are assigned to nanotube species with different chiral indices (n,m), as indicated in the figure. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Non‐linear optics on an exciton state in a single quantum dot
Authors: Melet Romain , Grousson Roger , Voliotis Valia , Wang Xue‐Lun 
Published: April 2008

AbstractWe report on non‐linear effects on the exciton ground state in a single quantum dot, driven by a strong resonant optical field. The resonant excitation is achieved by embedding the quantum dots in a waveguiding structure. Thus, the light–matter coupling is enhanced, allowing the observation of Rabi oscillations up to three periods. With increasing pulse area, a decrease of the exciton lifetime is observed leading to a very rapid damping of the oscillations amplitude. Resonant coherent control experiments show that the coherence time of the ground exciton state in a single quantum dot is fast, of the order of a few tens of picoseconds. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ultrafast tailoring of the exciton distribution in quantum wells
Authors: Amo A. , Ballarini D. , Kozhemyakina E. , Sanvitto D. , Kłopotowski Ł. , Viña L. , Bajoni D. , Bloch J. , Skolnick M. S. , Roberts J. S. 
Published: April 2008

AbstractBy excitation with two, consecutive, picosecond pulses we demonstrate that the distribution and temperature of a photocreated exciton population in semiconductor quantum wells can be dynamically tailored. The changes in the exciton distribution result in abrupt alterations of the photoluminescence dynamics, in particular in the appearance of a sudden decrease in the heavy‐hole excitonic emission when the second pulse impinges upon the sample. We present a quasi‐equilibrium thermodynamical model that includes the energy distribution of excitons and electron–hole plasma, which quantitatively accounts for the sharp dips observed in the exciton emission dynamics. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Neutron diffraction and magnetization measurements on CeNi4.2Mn0.8 and Y0.7Ni4.2Mn0.8
Authors: Toliński T. , Kaczorowski D. , Kowalczyk A. , Hoser A. , Stüßer N. , Talik E. , Klimczak L. M. 
Published: April 2008

AbstractThe cubic CeNi4Mn compound has been claimed to show a large spin‐polarization, magnetic moment and a high Curie temperature. To verify these properties we have carried out the magnetometric and neutron diffraction experiments on the nominally polycrystalline CeNi4Mn and YNi4Mn compounds. The real stoichiometry was estimated based on X‐ray photoemission and neutron diffraction as CeNi4.2Mn0.8 and Y0.7Ni4.2Mn0.8. The magnetic properties of Y0.7Ni4.2Mn0.8 have been studied with neutron diffraction to investigate the role of the rare earth in CeNi4.2Mn0.8. We have found that the samples crystallize in the hexagonal CaCu5‐type of structure. The deviation from the cubic structure is ascribed to the presence of a small nonstoichiometry. These structural changes are accompanied by a drop of the magnetic parameters. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ginkgo biloba extract improves coronary artery circulation in patients with coronary artery disease: contribution of plasma nitric oxide and endothelin‐1
Authors: Wu Yu‐Zhou , Li Shu‐Qin , Zu Xiu‐Guang , Du Jun , Wang Feng‐Fei 
Published: April 2008

AbstractIn patients with coronary artery disease (CAD), coronary blood flow is usually impaired due to imbalanced vasoactive substances such as nitric oxide (NO) and endothelin‐1 (ET‐1). The study was designed to test the effects of Ginkgo biloba extract (GBE) on the distal left anterior descending coronary artery (LAD) blood flow and plasma NO and ET‐1 levels. Eighty CAD patients were randomly assigned to GBE (n = 42) and control (n = 38) groups. The LAD blood flow was assessed non‐invasively using Doppler echocardiography at baseline and after 2 weeks. GBE treatment demonstrated a significant improvement in maximal diastolic peak velocity (MDPV), maximal systolic peak velocity (MSPV) and diastolic time velocity integral (DTVI) compared with controls (14.61 ± 4.51% vs 0.67 ± 2.66%, 9.03 ± 4.81% vs 0.34 ± 2.67% and 14.69 ± 5.08% vs 0.68 ± 3.00%, respectively, p < 0.01). NO was increased by 12.42% (p < 0.01), whereas ET‐1 was decreased by 5.82% (p < 0.01). The NO/ET‐1 ratio was increased by 19.47% (p < 0.01). A linear correlation was confirmed between the percentage change in LAD blood flow and in NO, ET‐1 or NO/ET‐1 ratio following GBE treatment. The results suggest that GBE treatment in CAD patients led to an increase of LAD blood flow, which might at least be related partly to the restoration of the delicate equilibrium between NO and ET‐1. Copyright © 2008 John Wiley & Sons, Ltd.
Acanthopanax senticosus suppresses reactive oxygen species production by mouse peritoneal macrophages in vitro and in vivo
Authors: Lin Qiu‐Ye , Jin Li‐Ji , Cao Zhen‐Hui , Lu Ya‐Nan , Xue Hong‐Yu , Xu Yong‐Ping 
Published: April 2008

AbstractExcess production of reactive oxygen species by macrophages has been implicated in many inflammatory diseases. The present study investigated the inhibitory effect of the stem bark extract of Acanthopanax senticosus on the production of superoxide anion and hydrogen peroxide in mouse peritoneal macrophages in vitro and in vivo. Exposure of mouse peritoneal macrophages to A. senticosus extract significantly suppressed superoxide anion production induced by zymosan in a dose‐dependent manner. Similarly, exposure of mouse peritoneal macrophages to A. senticosus extract significantly inhibited hydrogen peroxide production induced by phorbol 12‐myristate 13‐acetate (PMA) in a dose‐dependent manner. Intraperitoneal administration of A. senticosus extract to KM mice reduced the ex vivo production of zymosan induced‐superoxide anion and PMA‐induced hydrogen peroxide by their peritoneal macrophages. Exposure to A. senticosus extract did not affect the cell viability or systemic toxicity. A. senticosus inhibited reactive oxygen species production by mouse peritoneal macrophages in vitro and in vivo and may be partly responsible for the antiinflammatory function. Copyright © 2008 John Wiley & Sons, Ltd.
Large old trees influence patterns of δ13C and δ15N in forests
Authors: Weber Pascale , Bol Roland , Dixon Liz , Bardgett Richard D. 
Published: April 2008

AbstractLarge old trees are the dominant primary producers of native pine forest, but their influence on spatial patterns of soil properties and potential feedback to tree regeneration in their neighbourhood is poorly understood. We measured stable isotopes of carbon (δ13C) and nitrogen (δ15N) in soil and litter taken from three zones of influence (inner, middle and outer zone) around the trunk of freestanding old Scots pine (Pinus sylvestris L.) trees, to determine the trees' influence on below‐ground properties. We also measured δ15N and δ13C in wood cores extracted from the old trees and from regenerating trees growing within their three zones of influence. We found a significant and positive gradient in soil δ15N from the inner zone, nearest to the tree centre, to the outer zone beyond the tree crown. This was probably caused by the higher input of 15N‐depleted litter below the tree crown. In contrast, the soil δ13C did not change along the gradient of tree influence. Distance‐related trends, although weak, were visible in the wood δ15N and δ13C of regenerating trees. Moreover, the wood δ15N of small trees showed a weak negative relationship with soil N content in the relevant zone of influence. Our results indicate that large old trees control below‐ground conditions in their immediate surroundings, and that stable isotopes might act as markers for the spatial and temporal extent of these below‐ground effects. Copyright © 2008 John Wiley & Sons, Ltd.
Assessing morphologic complexity and diversity in river systems using three‐dimensional asymmetry indices for bed elements, bedforms and bar units
Authors: Rayburg Scott C. , Neave Mel 
Published: April 2008

AbstractGeomorphologists are becoming increasingly interested in assessing morphologic structure and the diversity and/or complexity in morphologic structure across multiple scales within river systems. Unfortunately, many of our existing tools/variables are unsuitable for this task because they do not work across multiple scales or with changing discharges. Asymmetry is one variable that can be used to either include or exclude variations in flow stage and that can be assessed across multiple scales. Existing asymmetry indices, however, are limited in scope and largely focus on only cross‐sectional form. This study examines three existing asymmetry indices in the cross‐stream and downstream planes (for cross‐sections and riffle or pools, respectively) and develops nine new asymmetry indices that incorporate vertical, cross‐stream and downstream asymmetry for bed elements (e.g. riffle crests, pool troughs, riffle entrance slope), bedforms (pools or riffles) and bar units (pool‐riffle sequences) to investigate the utility of asymmetry as a measure of morphologic structure and diversity in fluvial systems. These 12 indices are field tested on the Embarras River in East Central Illinois, USA. The results of this study indicate that there is considerable morphologic diversity in bed elements, bedforms and bar units both at bankfull and also with varying flow stage. This multi‐scale, multidimensional, multistage variability in morphologic structure highlights the complexity of natural river systems. The highly variable nature of fluvial form within a reach has important implications for river restoration and/or assessments of physical habitat or river health especially in instances where pools, riffles or pool‐riffle sequences are the focus of study. In general the most robust and useful combination of asymmetry indices for most applications includes A* and AL1 for bed elements and bedforms and AL3, AW and AH for bar units. Copyright © 2008 John Wiley & Sons, Ltd.