bluuebunny/crossref_metadata_2025_split huggingface dataset:
Advances in atomic data for neutron-capture elements
Authors: Sterling Nicholas C. , Witthoeft Michael C. , Esteves David A. , Stancil Phillip C. , Kilcoyne A. L. David , Bilodeau Rene C. , Aguilar Alejandro 
Published: August 2012

AbstractNeutron(n)-capture elements (atomic number Z > 30), which can be produced in planetary nebula (PN) progenitor stars via s-process nucleosynthesis, have been detected in nearly 100 PNe. This demonstrates that nebular spectroscopy is a potentially powerful tool for studying the production and chemical evolution of trans-iron elements. However, significant challenges must be addressed before this goal can be achieved. One of the most substantial hurdles is the lack of atomic data for n-capture elements, particularly that needed to solve for their ionization equilibrium (and hence to convert ionic abundances to elemental abundances). To address this need, we have computed photoionization cross sections and radiative and dielectronic recombination rate coefficients for the first six ions of Se and Kr. The calculations were benchmarked against experimental photoionization cross section measurements. In addition, we computed charge transfer (CT) rate coefficients for ions of six n-capture elements. These efforts will enable the accurate determination of nebular Se and Kr abundances, allowing robust investigations of s-process enrichments in PNe.
The second release of the Toruń catalogue of Galactic post-AGB objects: New classification scheme
Authors: Szczerba Ryszard , Siódmiak Natasza , Stasińska Grazyna , Borkowski Jozef , García-Lario Pedro , Suárez Olga , Hajduk Marcin , García-Hernández D. Anibal 
Published: August 2012

AbstractThe investigation of post-AGB objects (proto-planetary nebulae) is very important from the standpoint of physical and chemical changes occurring during the late stages of stellar evolution. The Toruń catalogue of Galactic post-AGB and related objects is an evolutive catalogue containing astrometric, photometric and spectroscopic data as well as HST images for all known post-AGB objects and candidates in our Galaxy. This free-access catalogue can serve as an ideal tool to study different groups of post-AGB objects, especially due to the fact that all information is gathered in one place. The second release of our catalogue introduces a simple classification scheme of post-AGB objects and includes a significant number of new objects, photometric data, spectra and images. Here, using objects from the catalogue we consider the problem of the termination of the AGB phase.
Weak emission line central stars of planetary nebulae
Authors: Todt Helga , Peña Miriam , Zühlke Julia , Oskinova Lida , Hamann Wolf-Rainer , Gräfener Götz 
Published: August 2012

AbstractTo understand the evolution and morphology of planetary nebulae, a detailed knowledge of their central stars is required. Central stars that exhibit emission lines in their spectra, indicating stellar mass-loss allow to study the evolution of planetary nebulae in action. Emission line central stars constitute about 10 % of all central stars. Half of them are practically hydrogen-free Wolf-Rayet type central stars of the carbon sequence, [WC], that show strong emission lines of carbon and oxygen in their spectra. In this contribution we address the weak emission-lines central stars (wels). These stars are poorly analyzed and their hydrogen content is mostly unknown. We obtained optical spectra, that include the important Balmer lines of hydrogen, for four weak emission line central stars. We present the results of our analysis, provide spectral classification and discuss possible explanations for their formation and evolution.
Expansion velocities of selected PNe
Authors: Torres-Peimbert Silvia , Arrieta Anabel , Georgiev Leonid 
Published: August 2012

AbstractIn order to clarify the observed relation between the expansion velocity measured from lines of different ions and their ionization potential, we present kinematical data for several objects. We have measured radial velocities on ESO UVES high dispersion spectra to compare expansion velocities for a set of planetary nebulae.
Dust distribution in circumstellar shells
Authors: van Marle Allard-Jan , Meliani Zakaria , Keppens Rony , Decin Leen 
Published: August 2012

AbstractWe present numerical simulations of the hydrodynamical interactions that produce circumstellar shells. These simulations include several scenarios, such as wind-wind interaction and wind-ISM collisions. In our calculations we have taken into account the presence of dust in the stellar wind. Our results show that, while small dust grains tend to be strongly coupled to the gas, large dust grains are only weakly coupled. As a result, the distribution of the large dust grains is not representative of the gas distribution. Combining these results with observations may give us a new way of validating hydrodynamical models of the circumstellar medium.
Maser kinematics and infrared properties of the water fountain IRAS 18286–0959
Authors: Yung Bosco H. K. , Nakashima Jun-ichi , Imai Hiroshi , Deguchi Shuji , Diamond Philip J. , Kwok Sun 
Published: August 2012

AbstractA “water fountain” is a transitional object between an AGB star and a PN. The VLBA observations of 22.2 GHz water maser emission reveal a “double-helix” outflow pattern from one of the water fountains, IRAS 18286–0959. The pattern is reasonably fit by a model consisting of two precessing jets. We propose that the two jets observed are a result of a single driving source with a significant proper motion. Using data from the AKARI catalogs, we also found that water fountains might have their own IR colors which are affected by the 9.7 μm silicate feature and the optical thickness of stellar envelopes. The colors could serve as new criteria for searching this type of rare objects.
Grp1‐associated scaffold protein (GRASP) is a regulator of the ADP ribosylation factor 6 (Arf6)‐dependent membrane trafficking pathway
Authors: Venkataraman Anand , Nevrivy Daniel J. , Filtz Theresa M. , Leid Mark 
Published: August 2012

AbstractGRASP interacts with Grp1 (general receptor for phosphoinositides 1; cytohesin 3), which catalyses nucleotide exchange on and activation of Arf6 (ADP‐ribosylation factor‐6). Arf6 is a low‐molecular‐mass GTPase that regulates key aspects of endocytic recycling pathways. Overexpressed GRASP accumulated in the juxtanuclear ERC (endocytic recycling compartment). GRASP co‐localized with a constitutively inactive mutant of Arf6 in the ERC such that it was reversed by expression of wild‐type Grp1. Co‐expression of GRASP and Grp1 promoted membrane ruffling, a cellular hallmark of Arf6 activation. GRASP accumulation in ERC was found to block recycling of the MHC‐I (major histocompatibility complex‐I), which is trafficked by the Arf6‐dependent pathway. In contrast, overexpression of GRASP had no effect on the recycling of transferrin receptors, which are trafficked by a clathrin‐dependent pathway. The findings suggest that GRASP regulates the non‐clathrin/Arf6‐dependent, plasma membrane recycling and signalling pathways.
Molecular Dynamics simulation of electrical field induced conformational transition and associated frictional performance of monomolecular films
Authors: Ma X , Shrotriya Pranav 
Published: August 2012

Abstract
Sparse monomolecular film assemblies with polar end groups such as carboxyl have attracted considerable interest because of their ability to undergo conformational transition under electrical fields. We report the results from molecular dynamics simulation of electrical field induced conformational transitions and associated frictional performance of carboxyl-terminated monomolecular films. Simulation results indicate that the density of the monomolecular film has a significant influence on the conformational transition under electrical fields. In the case of loose-packed monomolecular films, carboxyl-terminated chains cluster together to form a disordered film due to large interchain separation. Under the application of a positive electrical field, the chain backbone rotates and lies down on the substrate forming disordered clusters, whereas under the application of negative electrical fields, the chains stand up and cluster together to form disordered clusters. Under shallow indentation with a purely repulsive indenter, loose-packed monomolecular films subjected to a positive electrical field exhibit a lower level of frictional response compared with films subjected to negative and no electrical fields. In the case of close-packed monomolecular films, the molecular chains assemble in an ordered film and the space is not enough for backbone chains to generate large-scale conformational transition. Due to this spatial limitation, the applied electrical field was not found to have any influence on the backbone chain rotation and associated frictional response under shallow indentations with a purely repulsive indenter.
Development and Application of a Methodology to Determine Free Ferulic Acid and Ferulic Acid Ester‐Linked to Different Types of Carbohydrates in Cereal Products
Authors: Vaidyanathan Sharmila , Bunzel Mirko 
Published: August 2012

ABSTRACTFerulic acid bioavailability is dependent on its form present in food. This necessitates a methodology to quantify different groups of ferulic acid derivatives in food products, especially cereal‐based products. The aim of the proposed methodology is to separate and quantify ferulic acid ester‐linked to mono‐ and/or oligosaccharides (OF), to soluble polysaccharides (SPF), and to insoluble polysaccharides (IPF) as well as in its free form. Development and partial validation of this method, which was widely based on liquid/liquid extraction and precipitation steps, was performed using characterized standard materials isolated from corn bran. As the determination of OF was one of the major goals of this methodology, three different feruloylated mono‐ and oligosaccharides were used for method development and validation. To determine the accuracy of the method, ferulic acid–containing standard materials added to a starch matrix were extracted and separated according to the developed protocol. The separated ferulic acid esters were saponified before ferulic acid was analyzed by reversed phase HPLC. Recovery rates were generally between 70 and 103%, with the lowest recovery rates for SPF and highest recovery rates for IPF and OF. Finally, the applicability of the method to unprocessed and processed wheat bran samples was demonstrated.
Cooking, Roasting, and Fermentation of Chickpeas, Lentils, Peas, and Soybeans for Fortification of Leavened Bread
Authors: Baik Byung‐Kee , Han In Hwa 
Published: August 2012

ABSTRACTThe effects of cooking, roasting, and fermentation on the composition and protein properties of grain legumes and the characteristics of dough and bread incorporated with legume flours were determined to identify an appropriate pretreatment. Oligosaccharide content of legumes was reduced by 76.2–96.9% by fermentation, 44.0–64.0% by roasting, and 28.4–70.1% by cooking. Cooking and roasting decreased protein solubility but improved in vitro protein digestibility. Mixograph absorption of wheat and legume flour blends increased from 50–52% for raw legumes to 68–76, 62–64, and 74–80% for cooked, roasted, and fermented ones, respectively. Bread dough with cooked or roasted legume flour was less sticky than that with raw or fermented legume flour. Loaf volume of bread baked from wheat and raw or roasted legume flour blends with or without gluten addition was consistently highest for chickpeas, less for peas and lentils, and lowest for soybeans. Roasted legume flour exhibited more appealing aroma and greater loaf volume of bread than cooked legume flour, and it appears to be the most appropriate preprocessing method for incorporation into bread.
Vacuolar CAX1 and CAX3 Influence Auxin Transport in Guard Cells via Regulation of Apoplastic pH
Authors: Cho Daeshik , Villiers Florent , Kroniewicz Laetitia , Lee Sangmee , Seo You Jin , Hirschi Kendal D. , Leonhardt Nathalie , Kwak June M. 
Published: August 2012

AbstractCATION EXCHANGERs CAX1 and CAX3 are vacuolar ion transporters involved in ion homeostasis in plants. Widely expressed in the plant, they mediate calcium transport from the cytosol to the vacuole lumen using the proton gradient across the tonoplast. Here, we report an unexpected role of CAX1 and CAX3 in regulating apoplastic pH and describe how they contribute to auxin transport using the guard cell’s response as readout of hormone signaling and cross talk. We show that indole-3-acetic acid (IAA) inhibition of abscisic acid (ABA)-induced stomatal closure is impaired in cax1, cax3, and cax1/cax3. These mutants exhibited constitutive hypopolarization of the plasma membrane, and time-course analyses of membrane potential revealed that IAA-induced hyperpolarization of the plasma membrane is also altered in these mutants. Both ethylene and 1-naphthalene acetic acid inhibited ABA-triggered stomatal closure in cax1, cax3, and cax1/cax3, suggesting that auxin signaling cascades were functional and that a defect in IAA transport caused the phenotype of the cax mutants. Consistent with this finding, chemical inhibition of AUX1 in wild-type plants phenocopied the cax mutants. We also found that cax1/cax3 mutants have a higher apoplastic pH than the wild type, further supporting the hypothesis that there is a defect in IAA import in the cax mutants. Accordingly, we were able to fully restore IAA inhibition of ABA-induced stomatal closure in cax1, cax3, and cax1/cax3 when stomatal movement assays were carried out at a lower extracellular pH. Our results suggest a network linking the vacuolar cation exchangers to apoplastic pH maintenance that plays a crucial role in cellular processes.
The Grapevine Root-Specific Aquaporin VvPIP2;4N Controls Root Hydraulic Conductance and Leaf Gas Exchange under Well-Watered Conditions But Not under Water Stress
Authors: Perrone Irene , Gambino Giorgio , Chitarra Walter , Vitali Marco , Pagliarani Chiara , Riccomagno Nadia , Balestrini Raffaella , Kaldenhoff Ralf , Uehlein Norbert , Gribaudo Ivana , Schubert Andrea , Lovisolo Claudio 
Published: August 2012

Abstract
We functionally characterized the grape (Vitis vinifera) VvPIP2;4N (for Plasma membrane Intrinsic Protein) aquaporin gene. Expression of VvPIP2;4N in Xenopus laevis oocytes increased their swelling rate 54-fold. Northern blot and quantitative reverse transcription-polymerase chain reaction analyses showed that VvPIP2;4N is the most expressed PIP2 gene in root. In situ hybridization confirmed root localization in the cortical parenchyma and close to the endodermis. We then constitutively overexpressed VvPIP2;4N in grape ‘Brachetto’, and in the resulting transgenic plants we analyzed (1) the expression of endogenous and transgenic VvPIP2;4N and of four other aquaporins, (2) whole-plant, root, and leaf ecophysiological parameters, and (3) leaf abscisic acid content. Expression of transgenic VvPIP2;4N inhibited neither the expression of the endogenous gene nor that of other PIP aquaporins in both root and leaf. Under well-watered conditions, transgenic plants showed higher stomatal conductance, gas exchange, and shoot growth. The expression level of VvPIP2;4N (endogenous + transgene) was inversely correlated to root hydraulic resistance. The leaf component of total plant hydraulic resistance was low and unaffected by overexpression of VvPIP2;4N. Upon water stress, the overexpression of VvPIP2;4N induced a surge in leaf abscisic acid content and a decrease in stomatal conductance and leaf gas exchange. Our results show that aquaporin-mediated modifications of root hydraulics play a substantial role in the regulation of water flow in well-watered grapevine plants, while they have a minor role upon drought, probably because other signals, such as abscisic acid, take over the control of water flow.
A Set of Regioselective O-Methyltransferases Gives Rise to the Complex Pattern of Methoxylated Flavones in Sweet Basil
Authors: Berim Anna , Hyatt David C. , Gang David R. 
Published: August 2012

Abstract
Polymethoxylated flavonoids occur in a number of plant families, including the Lamiaceae. To date, the metabolic pathways giving rise to the diversity of these compounds have not been studied. Analysis of our expressed sequence tag database for four sweet basil (Ocimum basilicum) lines afforded identification of candidate flavonoid O-methyltransferase genes. Recombinant proteins displayed distinct substrate preferences and product specificities that can account for all detected 7-/6-/4′-methylated, 8-unsubstituted flavones. Their biochemical specialization revealed only certain metabolic routes to be highly favorable and therefore likely in vivo. Flavonoid O-methyltransferases catalyzing 4′- and 6-O-methylations shared high identity (approximately 90%), indicating that subtle sequence changes led to functional differentiation. Structure homology modeling suggested the involvement of several amino acid residues in defining the proteins’ stringent regioselectivities. The roles of these individual residues were confirmed by site-directed mutagenesis, revealing two discrete mechanisms as a basis for the switch between 6- and 4′-O-methylation of two different substrates. These findings delineate major pathways in a large segment of the flavone metabolic network and provide a foundation for its further elucidation.
Putative Glycosyltransferases and Other Plant Golgi Apparatus Proteins Are Revealed by LOPIT Proteomics
Authors: Nikolovski Nino , Rubtsov Denis , Segura Marcelo P. , Miles Godfrey P. , Stevens Tim J. , Dunkley Tom P.J. , Munro Sean , Lilley Kathryn S. , Dupree Paul 
Published: August 2012

AbstractThe Golgi apparatus is the central organelle in the secretory pathway and plays key roles in glycosylation, protein sorting, and secretion in plants. Enzymes involved in the biosynthesis of complex polysaccharides, glycoproteins, and glycolipids are located in this organelle, but the majority of them remain uncharacterized. Here, we studied the Arabidopsis (Arabidopsis thaliana) membrane proteome with a focus on the Golgi apparatus using localization of organelle proteins by isotope tagging. By applying multivariate data analysis to a combined data set of two new and two previously published localization of organelle proteins by isotope tagging experiments, we identified the subcellular localization of 1,110 proteins with high confidence. These include 197 Golgi apparatus proteins, 79 of which have not been localized previously by a high-confidence method, as well as the localization of 304 endoplasmic reticulum and 208 plasma membrane proteins. Comparison of the hydrophobic domains of the localized proteins showed that the single-span transmembrane domains have unique properties in each organelle. Many of the novel Golgi-localized proteins belong to uncharacterized protein families. Structure-based homology analysis identified 12 putative Golgi glycosyltransferase (GT) families that have no functionally characterized members and, therefore, are not yet assigned to a Carbohydrate-Active Enzymes database GT family. The substantial numbers of these putative GTs lead us to estimate that the true number of plant Golgi GTs might be one-third above those currently annotated. Other newly identified proteins are likely to be involved in the transport and interconversion of nucleotide sugar substrates as well as polysaccharide and protein modification.
Ageing and employers’ perceptions of labour costs and productivity
Authors: Conen Wieteke S. , van Dalen Hendrik P. , Henkens Kène 
Published: August 2012

PurposeThe purpose of this paper is to examine employers’ perceptions of changes in the labour cost‐productivity gap due to the ageing of the workforce, the effects of tenure wages and employment protection on the perceived gap, and whether a perceived labour cost‐productivity gap affects employers’ recruitment and retention behaviour towards older workers.Design/methodology/approachThe authors analyse surveys administered to employers in Denmark, France, Germany, Italy, the Netherlands, Poland and Sweden.FindingsApproximately half of employers associate the ageing of the personnel with a growing gap between labour costs and productivity. Both the presence of tenure wages and employment protection rules increase the probability of employers perceiving a widening labour cost‐productivity gap due to the ageing of their workforce. A counterfactual shows that even when employment protection and tenure wage systems are abolished, 40 percent of employers expect a net cost increase. The expected labour cost‐productivity gap negatively affects both recruitment and retention of older workers.Originality/valueIn this paper, the wage‐productivity gap is examined through the perceptions of employers using an international comparative survey.
How do employed women perceive the reconciliation of work and family life?
Authors: Hennig Marina , Stuth Stefan , Ebach Mareike , Erika Hägglund Anna 
Published: August 2012

PurposeThe purpose of this paper is to analyze how employed women perceive the reconciliation of work and family life in Denmark, Germany, France, Finland, Great Britain, Sweden and Switzerland. The paper seeks to explore why women in certain countries are more successful in combining family responsibilities with gainful employment.Design/methodology/approachDrawing on data from the International Social Survey Programme (ISSP) 2005, the questions are addressed by applying country specific linear regression analysis at the individual level, correlations at the country level as well as policy analysis.FindingsThe analysis shows that the most important factors influencing employed women's perception of the reconciliation are work load, the presence of children in the household and part‐time employment. In addition, the findings point at cross‐national differences. In countries where family policies focus on integrating men and women into the labour market, women rate the reconciliation of work and family life higher than in countries whose family policies aim at supporting the family.Research limitations/implicationsBy comparing seven European countries the paper shows that family policies are closely related to employed women's perceptions of the reconciliation. In order to understand the interaction between the individual perception and the institutional framework, the paper suggests that further research is needed on women's perceptions in each country.Originality/valueThe paper explores how employed women perceive the reconciliation of work and family life in seven European countries and explains the differences by means of family policies.