bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterizing protein glycosylation sites through higher‐energy C‐trap dissociation
Authors: Segu Zaneer M. , Mechref Yehia
Published: March 2010

Assigning glycosylation sites of glycoproteins and their microheterogeneity is still a very challenging analytical task despite the rapid advancements in mass spectrometry. It is shown here that glycopeptide ions can be fragmented efficiently using the higher‐energy C‐trap dissociation (HCD) feature of a linear ion trap orbitrap hybrid mass spectrometer (LTQ Orbitrap). An attractive aspect of this dissociation option is the generation of distinct Y1 ions (peptide+GlcNAc), thus allowing unequivocal assignment of N‐glycosylation sites of glycoproteins. The combination of the very informative collision‐induced dissociation spectra acquired in the linear ion trap with the distinct features of HCD offers very useful information aiding in the characterization of the glycosylation sites of glycoproteins. The HCD activation energy needed to obtain optimum Y1 ions was studied in terms of glycan structure and charge state, and size and structure of the peptide backbone. The latter appeared to be primarily dictating the needed HCD energy. The distinct Y1 ion formation in HCD facilitated an easy assignment of such an ion and its subsequent isolation and dissociation through multiple‐stage tandem mass spectrometry. The resulting MS3 spectrum of the Y1 ion facilitates database searching and de novo sequencing thus prompting the subsequent identification of the peptide backbone and associated glycosylation sites. Moreover, fragment ions formed by HCD are detected in the Orbitrap, thus overcoming the 1/3 cut‐off limitation that is commonly associated with ion trap mass spectrometers. As a result, in addition to the Y1 ion, the common glycan oxonium ions are also detected. The high mass accuracy offered by the LTQ Orbitrap mass spectrometer is also an attractive feature that allows a confident assignment of protein glycosylation sites and the microheterogeneity of such sites. Copyright © 2010 John Wiley & Sons, Ltd.
P450‐catalyzed vs. electrochemical oxidation of haloperidol studied by ultra‐performance liquid chromatography/electrospray ionization mass spectrometry
Authors: Mali'n Tove Johansson , Weidolf Lars , Castagnoli Neal , Jurva Ulrik
Published: March 2010

The metabolites formed via the major metabolic pathways of haloperidol in liver microsomes,N‐dealkylation and ring oxidation to the pyridinium species, were produced by electrochemical oxidation and characterized by ultra‐performance liquid chromatography/electrospray ionization mass spectrometry (UPLC/ESI‐MS). Liver microsomal incubations and electrochemical oxidation in the presence of potassium cyanide (KCN) resulted in two diastereomeric cyano adducts, proposed to be generated from trapping of the endocyclic iminium species of haloperidol. Electrochemical oxidation of haloperidol in the presence of KCN gave a third isomeric cyano adduct, resulting from trapping of the exocyclic iminium species of haloperidol. In the electrochemical experiments, addition of KCN almost completely blocked the formation of the major oxidation products, namely theN‐dealkylated products, the pyridinium species and a putative lactam. This major shift in product formation by electrochemical oxidation was not observed for the liver microsomal incubations where theN‐dealkylation and the pyridinium species were the major metabolites also in the presence of KCN. The previously not observed dihydropyridinium species of haloperidol was detected in the samples, both from electrochemical oxidation and the liver microsomal incubations, in the presence of KCN. The presence of the dihydropyridinium species and the absence of the corresponding cyano adduct lead to the speculation that an unstable cyano adduct was formed, but that cyanide was eliminated to regenerate the stable conjugated system. The formation of the exocyclic cyano adduct in the electrochemical experiments but not in the liver microsomal incubations suggests that the exocyclic iminium intermediate, obligatory in the electrochemically mediatedN‐dealkylation, may not be formed in the P450‐catalyzed reaction. Copyright © 2010 John Wiley & Sons, Ltd.
Delay‐dependent dissipativity analysis and synthesis of switched delay systems
Authors: Mahmoud Magdi S.
Published: March 2010

In this paper, we study the problem of dissipative analysis for a class of switched systems with time‐varying delays. Sufficient conditions for dissipativity are developed for a class of switching signals with average dwell time. These conditions express delay‐dependent exponential stability and are provided in terms of linear matrix inequalities (LMIs). It is shown that the derived results encompass some available results on ℋ︁∞approach and arbitrary switching case. Numerical examples are given to illustrate the developed results. Copyright © 2010 John Wiley & Sons, Ltd.
Controller coefficient truncation using Lyapunov performance certificate
Authors: Skaf Joëlle , Boyd Stephen P.
Published: March 2010

We describe a method for truncating the coefficients of a linear controller while guaranteeing that a given set of relaxed performance constraints is met. Our method sequentially and greedily truncates individual coefficients, using a Lyapunov certificate, typically in linear matrix inequality (LMI) form, to guarantee the performance. Numerical examples show that the method is surprisingly effective at finding controllers with aggressively truncated coefficients, which meet typical performance constraints. We give an example showing that how the basic method can be extended to handle nonlinear plants and controllers. Copyright © 2010 John Wiley & Sons, Ltd.
Robust control of uncertain nonlinear systems with state delays based on an uncertainty and disturbance estimator
Authors: Kuperman Alon , Zhong Qing‐Chang
Published: March 2010

In this article, one linear and one nonlinear robust control strategies are proposed for uncertain nonlinear continuous‐time systems with disturbances and state delays. The approaches are based on the uncertainty and disturbance estimator (UDE) introduced in 2004. In the case of a linear controller, the terms containing the nonlinear functions and time delays are treated as additional disturbances to the system. In the case of a nonlinear controller, both known and unknown delay scenarios are considered. In the case of an unknown time delay, the terms containing the delay are treated as additional disturbances to the system. The algorithms provide excellent tracking and disturbance rejection performance. Simulations are given to show the effectiveness of the strategies, first via a simple example and second via an application to a continuous stirred tank reactor system. Copyright © 2010 John Wiley & Sons, Ltd.
Chemical and crystallographic study of remineralized surface on initial carious enamel treated with Galla chinensis
Authors: Zhang Ling‐Lin , Li Ji‐Yao , Zhou Xue‐Dong , Cui Fu‐Zhai , Wei Li
Published: March 2010

To investigate the morphologic, chemical and crystallographic characters of remineralized surface on initial carious enamel treated with Galla chinensis, scanning electron microscopy equipped with energy dispersive analysis spectroscopy were used, and X‐ray microdiffraction (microzone XRD) was used for the first time to analyze in situ the microzone crystallite of remineralized surface on carious enamel. Bovine sound enamel slabs were demineralized to produce initial carious lesion in vitro. Then, the lesions were exposed to a pH‐cycling regime for 12 days of remineralization. Each daily cycle included 4×1 min applications with one of the three treatments: distilled and deionized water (DDW); 1 g/L NaF; 4 g/L G. chinensis extract (GCE). After the treatments, some rod‐like deposits and many irregular prominences were found on GCE‐treated enamel surface, and the intensities of Ca and P signals showed a tendency to increase; Ca:P ratio was significantly higher than that of DDW‐treated enamel. X‐ray microdiffraction showed hydroxyapatite was still the main component of GCE‐treated enamel, and the crystallinity was increased, the crystal lattice changed gently with decreased lattice parameter a. These results indicated the potential of GCE in promoting the remineralization of initial enamel carious lesions, and supported the previous hypothesis about GCE mechanism. Combined with the anti‐bacteria and demineralization inhibition properties of GCE, the natural G. chinensis may become one more promising agent for caries prevention. SCANNING 31: 236–245, 2009. © 2010 Wiley Periodicals, Inc.
Growth of ZnO nanorod arrays by hydrothermal method using homo‐seed layers annealed at various temperatures
Authors: Bae Young Sook , Kim Dong Chan , Ahn Cheol Hyoun , Kim Jae Hyun , Cho Hyung Koun
Published: March 2010

Vertically arrayed ZnO nanorods were synthesized by a hydrothermal method on homo‐seed layers deposited using a sol‐gel process and heat‐treated at various temperatures ranging from 400 to 700 °C in air. The effect of the annealing temperatures on nanorod formation was investigated. With increasing temperature, the microstructure of the ZnO seed layers changed from nanocrystals to coarse polycrystals with a preferred orientation, which led to an increase in the length and diameter of the hydrothermally grown nanorods. The ZnO nanorods, based on a solution process, exhibited deep‐level emission in the orange‐red region related with hydroxyl group reactions, while the thermally treated seed layers showed oxygen vacancy‐related emission. Copyright © 2010 John Wiley & Sons, Ltd.
Investigation of the UV/O3 treatment of ultrananocrystalline diamond films
Authors: Kulisch W. , Popov C. , Gilliland D. , Ceccone G. , Rossi F. , Reithmaier J. P.
Published: March 2010

Surface analytical techniques such as XPS, time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) and contact angle measurements have been applied to investigate the effects of UV/O3 treatments used to render the original hydrogen termination of ultrananocrystalline diamond/amorphous carbon composite films to an OH‐termination. The main parameter varied was the treatment time. For comparison purposes, a sample treated by a microwave O2 plasma for 10 min, and a sample treated with UV light without the ozone‐forming 185 nm emission have also been investigated. The standard UV/O3 treatment leads to the following effects: i) the surface becomes oxidized with a final oxygen surface concentration of about 10%; ii) this oxygen is present at the surface mainly in the form of OH groups; iii) the contact angle against purified water drops from 85° for as‐grown samples to 5° ± 2° for UV/O3‐treated surfaces; iv) the surface energy increases by a factor of two, reaching 78 mN/m; in addition, this surface energy is almost exclusively of polar nature. These developments are almost completed after 20 min of UV/O3 treatment. Similar results can be achieved by O2 plasma treatment, while blocking the ozone‐forming 185 nm line of the UV lamp leads to only marginal changes of the as‐grown surface, thus proving that O3 plays a crucial role in the oxidation process. Copyright © 2010 John Wiley & Sons, Ltd.
Exchange bias in epitaxial CoO/Fe bilayer grown on MgO(001)
Authors: Gurgul J. , Freindl K. , Kozioł‐Rachwał A. , Matlak K. , Spiridis N. , Ślȩzak T. , Wilgocka‐Ślȩzak D. , Korecki J.
Published: March 2010

Exchange bias (EB) is studied in an epitaxial CoO/Fe bilayer grown by molecular beam epitaxy on MgO(001). The characterization of the layer structure and interface quality was performed using LEED, AES and conversion electron Mössbauer spectroscopy(CEMS). Detailed experimental studies of the EB effect as a function of temperature were carried out using the magneto‐optical Kerr effect. Notwithstanding the formation of Fe oxides at the CoO/Fe interface, as evidenced by the CEMS measurements, we observed a negative EB with blocking temperature TB = 257 K. At temperatures close to TB, the coercive field reaches a maximum, which is in agreement with the Stiles and McMichael model. Copyright © 2010 John Wiley & Sons, Ltd.
Co‐operative Formation of Monolithic Tungsten Oxide–Polybenzylene Hybrids via Polymerization of Benzyl Alcohol and Study of the Catalytic Activity of the Tungsten Oxide Nanoparticles
Authors: Olliges‐Stadler Inga , Rossell Marta D. , Niederberger Markus
Published: March 2010

Hard and brittle monolithic tungsten oxide‐polybenzylene nanohybrids can be obtained in one step by reacting tungsten iso‐propoxide with benzyl alcohol. In a first step, crystalline tungsten oxide W18O49 nanowires with a diameter of about 1.5 nm form via ether elimination reaction. Subsequently, the large residue of the benzyl alcohol is transformed to dibenzyl ether, which then polymerizes to polybenzylene, incorporating the nanoparticles into the forming polymer. The catalytic effect of the tungsten oxide nanowires on the quantitative formation of polybenzylene is proven by reacting them in different concentrations and at varying temperatures either with benzyl alcohol or with dibenzyl ether. Complete polymerization of benzyl alcohol is achieved within just 30 min by using a particle‐to‐monomer molar ratio of 1:115 at 160  °C. Lower reaction temperatures (100–130  °C) or higher ratios (1:340 and 1:680) prolong the reaction time to several hours. Further studies show that the tungsten oxide nanoparticles are able to completely polymerize various other alcohols with an aryl methanol group.
Toward mechanistic elucidation of iron acquisition in barley: efficient synthesis of mugineic acids and their transport activities
Authors: Namba Kosuke , Murata Yoshiko
Published: March 2010

Iron acquisition of graminaceous plants is characterized by the synthesis and secretion of iron‐chelating compounds, mugineic acids (MAs), and by a specific uptake system for MAs‐iron(III) complexes. We identified a transporter, HvYS1 (Hordeum vulgare L. yellow stripe 1), that is highly specific for MAs‐iron(III) in barley roots. In this article we outline the characterization of HvYS1, and our recent work on the practical syntheses of MAs and investigations into the molecular basis of the specific transport of their iron(III) complexes by HvYS1. 2′‐Deoxymugineic acid (DMA) was synthesized in a good overall yield from commercially available Boc‐l‐allylglycine using a minimal number of short simple operations with minimal protecting groups and work‐up/purification procedures. The same strategy was also successfully applied to β‐hydroxy‐l‐allylglycine, which was obtained by an allylic oxidation of l‐allylglycine derivatives, to give MA and 2′‐epi‐MA efficiently. HvYS1 transported the iron(III) complexes of all three synthetic specimens with efficiency similar to that of a natural mugineic acid complex. With sufficient quantities of MAs in hand, we analyzed the function of HvYS1 and revealed by preparing chimeric transporters that the sixth outer membrane loop of the transporter plays a vital role in substrate specificity. © 2010 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 10: 140–150; 2010: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.200900028
Integration der Gesellschaft in die Zielformulierung der Regionen
Authors: Thrun Thomas
Published: March 2010

More importance must be attached to social participation if the role of regional planning processes is to be strengthened and implementation deficits redressed. Participation in regional planning can be practicable, as is shown by examples such as the regional amalgamation of the results of local participation processes, the extending of cooperation with social groups, initiating regional discussions via the media, and formal statement proceedings. Due to the lack of evaluation studies, the contribution of extended participation towards sustainable development can only be estimated, but there would seem to be potential for the step-by-step extension of participation at a regional level.
Das Internet in Deutschland
Authors: Langhagen-Rohrbach Christian
Published: March 2010

The Internet as a virtual medium is often considered to be placeless. This article tries to find out that even the Internet has a regional structure in “real” space. This structure depends on infrastructure (networks) as well as on existing spatial patterns of places. So the Internet intensifies existing regional disparities. The growth pattern of the Internet in Germany shows the same pattern as it is well known from the diffusion of any other innovation. The German Internet Toplevel-Domain “.de” is an example of this growth pattern in Germany.
Regionalisierte Szenarien des Klimawandels
Authors: Jacob Daniela
Published: March 2010

Global climate change initiates changes in regions as well. These changes can be calculated using regional climate change scenarios. For Germany first results show an increase of the annual mean temperatures between 2.5 and 3.5°C depending on the assumed emission scenario. Winter temperatures can rise by about 4°C in the South or Southeast of Germany. It seems that the annual precipitation sums do not change, but the annual cycle of precipitation might get more extreme. The results indicate a decrease of summer precipitation up to 30% in some regions of Germany and an increase in the winter months of more than 30%.
Handlungs- und Steuerungsfähigkeit von Städten und Regionen im Klimawandel
Authors: Frommer Birte
Published: March 2010

On one hand cities and regions are causing climate change and on the other hand they are affected by climate change. Therefore, they are obliged to develop and implement climate protection and climate adaptation measures. As climate change can not be stopped any more but only decreased, adaptation is becoming more and more important — in addition to further climate protection. This paper aims to clarify a theoretical comprehension of regional strategies of climate change adaptation. It introduces a concept for the development of regional adaptation strategies based on a broad comprehension of strategic planning. A strategy cycle with eight appropriate planning steps shall help to increase adaptive capacity at regional level.
Erneuerbare Energien — Räumliche Dimensionen, neue Akteurslandschaften und planerische (Mit)Gestaltungspotenziale am Beispiel des Biogaspfades
Authors: Kanning Helga , Buhr Nina , Steinkraus Katharina
Published: March 2010

The transition of the energy supply into a sustainable system is a task of historical dimension. Today different land uses compete for the scarce available land. Therefore, if regional potentials of renewable energies are to be developed in a sustainable way, the regions need to support this change in a proactive manner. Thereby, new challenges emerge for spatial planning.

The biogas process chain is a promising regional energy source that contributes to climate protection and positively influences the regional economy. Using the biogas example emerging interactions between forms of land use, new players and options for planning involvement are highlighted. Furthermore, a conceptual approach is presented which uses a combination of formal and informal planning instruments. This approach enables spatial planning to proactively support the sustainable use of available regional energy resources in the future.
Raumplanerische Anpassung an den Klimawandel im Spiegel aktueller Projekte
Authors: Meyer Katrin , Overbeck Gerhard
Published: March 2010

Spatial planning understood as a comprehensive planning and supra-local planning can make an important contribution to adaptation to climate change. A number of project activities dealing with adaptation have started in recent years — often including a specific reference to spatial planning. This article aims at giving a thematic review of recent projects and to draw conclusions for a further advancement of spatial planning and spatial research.
Wissensträger und Wissensvernetzung in Metropolregionen. Raumansprüche von Wissensträgern und die Verknüpfung von Politiken
Authors: Growe Anna
Published: March 2010

In politics and planning, a discussion of knowledge-holders is characterized through reductions, e.g. by focusing on creative people and their affinity for an urban environment. This article evaluates the strategies of metropolitan areas to show what kinds of problems exist within the transfer of information about knowledge-holders into planning strategies. Furthermore, different perspectives are elaborated that show heterogeneous requirements from the private and professional lives of knowledge-holders. These cause different spatial requirements and therefore form the basis for a differentiated development of spatial strategies.
Eco‐cultural health, global health, and sustainability
Authors: Rapport David J. , Maffi Luisa
Published: March 2010

Anthropogenic stress on the earth's ecosystems has resulted in widespread prevalence of ecosystem distress syndrome, a quantifiable set of signs of ecosystem degradation. At the same time, the planet is witnessing rapid declines in global cultural diversity and in the vitality of the world's cultures, which closely mirror, and are interrelated with, ecological degradation. As a consequence of this converging crisis of loss of ecosystem and cultural health, global health and sustainability are increasingly under threat. An eco‐cultural health perspective based on understanding the linkages between human activities, ecological and cultural disruption, and public health is essential for addressing these threats and achieving global sustainability.
Inter‐annual and inter‐plot variations of wood biomass production as related to biotic and abiotic characteristics at a deciduous forest in complex terrain, Korea
Authors: Kim Youngil , Kang Sinkyu , Lim Jong‐Hwan , Lee Dowon , Kim Joon
Published: March 2010

This study aims to evaluate inter‐annual and inter‐plot variation of wood biomass production (WBP) and to investigate the relationships of the WBP variations with several biotic and abiotic characteristics at a deciduous forest in complex terrain, the Gwangneung Experimental Forest, Korea. Based on field survey in the plot‐scale study area, WBP during 1991–2004 was estimated by a dendrochronological method. Our field data indicated that the inter‐annual variation of WBP was closely related to the seasonal climate of both winter air temperature and spring precipitation. The inter‐plot variation of WBP was highly associated with basal area, biomass, and frequency of Quercus spp. in the plots, and correlations of the inter‐plot variation with the stand characteristics of the specific species were stronger than those with slope and soil water content. Our results suggest that the annual fluctuation of forest productivity is primarily governed by severe climate in a season of the year, and the spatial distribution of a dominant species largely represent plot variation in the productivity. Our findings contribute to an enhanced understanding of climatic effects on the annual variability of forest productivity and the spatial heterogeneity of the productivity, which are extensively concerned with forested ecosystems of Korea.
Effects of soil water conditions on the morphology, phenology, and photosynthesis of Betula ermanii in the boreal forest
Authors: Tabata Azusa , Ono Kiyomi , Sumida Akihiro , Hara Toshihiko
Published: March 2010

Four 2‐year watering treatments were applied to Betula ermanii seedlings to investigate their responses to soil water conditions: ID [irrigated well (I) in the previous year and water deficit (D) in the current year], DD, DI, and II. RGR of the seedlings in current‐year water deficit without experiencing previous‐year water deficit (ID) was smaller than that of seedlings irrigated well in both years (II). Surprisingly, RGR did not differ between 2‐year‐water‐deficited (DD) and ‐well‐irrigated (II) treatments. There was no difference in the area‐based photosynthetic rate of the late leaves, which are formed in the current‐year environment, between the four water treatments, but their leaf longevity was shortened by water deficit. Area‐based photosynthetic rate of the early leaves, whose buds are formed in the previous year environment, was smaller in ID than in II, but it did not differ between DD and II. The de‐epoxidation state of the xanthophyll cycle was greater in ID than in DD. Leaf mass per area (leaf dry weight/leaf area) did not differ among the four water treatments. Specific root length (root total length/root dry weight) did not differ between ID and II. It was greater in DD than in II, probably resulting in increased water uptake efficiency. Photoprotective systems such as xanthophyll contents and antioxidant enzyme activities did not differ among the four treatments. Morphological responses of B. ermanii roots seem to be important as whole‐plant‐level responses to water deficit for maintaining RGR, in addition to leaf‐level photosynthetic and phenological responses of two types of leaves. Our results partly explain how B. ermanii seedlings survive and maintain growth even under varying soil water conditions in the boreal forest.
Accumulative Equating Error after a Chain of Linear Equatings
Authors: Guo Hongwen
Published: March 2010

After many equatings have been conducted in a testing program, equating errors can accumulate to a degree that is not negligible compared to the standard error of measurement. In this paper, the author investigates the asymptotic accumulative standard error of equating (ASEE) for linear equating methods, including chained linear, Tucker, and Levine, under the nonequivalent groups with anchor test (NEAT) design. A recursive formula for the ASEE is provided for a series of equatings that makes use of only historical summary statistics. This formula can serve as a new tool to measure the magnitude of equating errors that have accumulated over a series of equatings, and to help monitor and design testing programs.
Saturated Fat and Cardiometabolic Risk Factors, Coronary Heart Disease, Stroke, and Diabetes: a Fresh Look at the Evidence
Authors: Micha Renata , Mozaffarian Dariush
Published: March 2010

Dietary and policy recommendations frequently focus on reducing saturated fatty acid consumption for improving cardiometabolic health, based largely on ecologic and animal studies. Recent advances in nutritional science now allow assessment of critical questions about health effects of saturated fatty acids (SFA). We reviewed the evidence from randomized controlled trials (RCTs) of lipid and non‐lipid risk factors, prospective cohort studies of disease endpoints, and RCTs of disease endpoints for cardiometabolic effects of SFA consumption in humans, including whether effects vary depending on specific SFA chain‐length; on the replacement nutrient; or on disease outcomes evaluated. Compared with carbohydrate, the TC:HDL‐C ratio is nonsignificantly affected by consumption of myristic or palmitic acid, is nonsignificantly decreased by stearic acid, and is significantly decreased by lauric acid. However, insufficient evidence exists for different chain‐length‐specific effects on other risk pathways or, more importantly, disease endpoints. Based on consistent evidence from human studies, replacing SFA with polyunsaturated fat modestly lowers coronary heart disease risk, with ~10% risk reduction for a 5% energy substitution; whereas replacing SFA with carbohydrate has no benefit and replacing SFA with monounsaturated fat has uncertain effects. Evidence for the effects of SFA consumption on vascular function, insulin resistance, diabetes, and stroke is mixed, with many studies showing no clear effects, highlighting a need for further investigation of these endpoints. Public health emphasis on reducing SFA consumption without considering the replacement nutrient or, more importantly, the many other food‐based risk factors for cardiometabolic disease is unlikely to produce substantial intended benefits.
Synthesis and Physical Properties of Potential Biolubricants based on Ricinoleic Acid
Authors: Yao Linxing , Hammond Earl G. , Wang Tong , Bhuyan Satyam , Sundararajan Sriram
Published: March 2010

The desire to replace petroleum‐based materials with environmentally friendly and sustainable alternatives has stimulated the development of vegetable oil‐based materials as biolubricants. Our studies have focused on molecules that might be produced by biosynthesis of genetically altered oilseed plants with limited post‐harvest modification. Various ricinoleate and 12‐hydroxystearate esters and estolides were synthesized and their melting points and viscosities were documented. The antifriction and antiwear properties of some esters were evaluated with a microtribometer. The purities of all the products were >98–99% by gas chromatography. Some of these compounds showed melting points, viscosities, and lubricity suitable for uses as biolubricants. Various ricinoleate esters acylated at the 12 positions with short‐chain acids were particularly promising.
Targeted knock‐out of a gene encoding sulfite reductase in the moss Physcomitrella patens affects gametophytic and sporophytic development
Authors: Wiedemann Gertrud , Hermsen Corinna , Melzer Michael , Büttner-Mainik Annette , Rennenberg Heinz , Reski Ralf , Kopriva Stanislav
Published: March 2010

A key step in sulfate assimilation into cysteine is the reduction of sulfite to sulfide by sulfite reductase (SiR). This enzyme is encoded by three genes in the moss Physcomitrella patens. To obtain a first insight into the roles of the individual isoforms, we deleted the gene encoding the SiR1 isoform in P. patens by homologous recombination and subsequently analysed the ΔSiR1 mutants. While ΔSiR1 mutants showed no obvious alteration in sulfur metabolism, their regeneration from protoplasts and their ability to produce mature spores was significantly affected, highlighting an unexpected link between moss sulfate assimilation and development, that is yet to be characterized.
Lipid droplets lighting up: Insights from live microscopy
Authors: Digel Margarete , Ehehalt Robert , Füllekrug Joachim
Published: March 2010

Lipid droplets emerge as important intracellular organelles relevant for lipid homeostasis and the pathophysiology of metabolic diseases. Here, we present a personal view on the current knowledge about the biogenesis of mammalian cytoplasmic lipid droplets, with a focus on microscopy and especially live imaging. We also discuss difficulties related to the lipid droplet proteome, contentious views on lipid droplet growth, and last but not least the evidence for the heterogeneity of lipid droplets within a single cell. We conclude with an outline of the most important future challenges.
ROS leads to MnSOD upregulation through ERK2 translocation and p53 activation in selenite‐induced apoptosis of NB4 cells
Authors: Li Zhushi , Shi Kejian , Guan Liying , Cao Tingming , Jiang Qian , Yang Yang , Xu Caimin
Published: March 2010

Following our previous finding that sodium selenite induces apoptosis in human leukemia NB4 cells, we now show that the expression of the critical antioxidant enzyme manganese superoxide dismutase (MnSOD) is remarkably elevated during this process. We further reveal that reactive oxygen species (ROS), especially superoxide radicals, play a crucial role in selenite‐induced MnSOD upregulation, with extracellular regulated kinase (ERK) and p53 closely implicated. Specifically, ERK2 translocates into the nucleus driven by ROS, where it directly phosphorylates p53, leading to dissociation of p53 from its inhibitory protein mouse double minute 2 (MDM2). Active p53 directly mediates the expression of MnSOD, serving as the link between ERK2 translocation and MnSOD upregulation.
Rac1 modulates TGF‐β1‐mediated epithelial cell plasticity and MMP9 production in transformed keratinocytes
Authors: Santibáñez Juan F. , Kocić Jelena , Fabra Angels , Cano Amparo , Quintanilla Miguel
Published: March 2010

Transforming growth factor‐β1 (TGF‐β1) activates Rac1 GTPase in mouse transformed keratinocytes. Expression of a constitutively active Q61LRac1 mutant induced an epithelial to mesenchymal transition (EMT) linked to stimulation of cell migration and invasion. On the contrary, expression of a dominant‐negative N17TRac1 abolished TGF‐β1‐induced cell scattering, migration and invasion. Moreover, Q61LRac1 enhanced metalloproteinase‐9 (MMP9) production to levels comparable to those induced by TGF‐β1, while N17TRac1 was inhibitory. TGF‐β1‐mediated EMT involves the expression of the E‐cadherin repressor Snail1, regulated by the Rac1 and mitogen‐activated protein kinase (MAPK) pathways. Furthermore, MMP9 production was MAPK‐dependent, as the MEK inhibitor PD98059 decreased TGF‐β1‐induced MMP9 expression and secretion in Q61LRac1 expressing cells. We propose that regulation of TGF‐β1‐mediated plasticity of transformed keratinocytes requires the cooperation between the Rac1 and MAPK signalling pathways.
The psychological underpinnings of relative thinking in price comparisons
Authors: Saini Ritesh , Thota Sweta C.
Published: March 2010

This article investigates the psychological underpinnings of relative thinking—the tendency of consumers to consider relative savings, and not just absolute savings, in their decisions to search for a deal or purchase an item. We examine how (i) cognitive load, (ii) the affective‐richness of the product, and (iii) the consumer's propensity for intuitive decision‐making influence relative thinking. As hypothesized, high cognitive load and affect‐rich (vs. affect‐poor) products, and individual level preference for intuitive decision‐making aggravate this behavior. Our results present clear managerial implications along with developing a better understanding of the behavioral foundations of relative thinking.
Study of molecular targets influencing homocysteine and cholesterol metabolism in growing rats by manipulation of dietary selenium and methionine concentrations
Authors: Wolf Nicole M. , Mueller Kristin , Hirche Frank , Most Erika , Pallauf Josef , Mueller Andreas S.
Published: March 2010

Inconsistent results exist from human and animal studies for Se and methionine (Met) regarding their influence on homocysteine (HCys) and cholesterol (Chol) metabolism. To elucidate these contradictions, sixty-four weanling albino rats were divided into eight groups of 8, and were fed diets containing four different Se levels (15, 50, 150 and 450 μg/kg) either in combination with the recommended Met level of 3 g/kg (C15, C50, C150 and C450) or with an increased Met concentration of 15 g/kg (M15, M50, M150 and M450) for 8 weeks. Plasma HCys was twofold higher in the Se-supplemented C groups than in group C15. Met addition also doubled plasma HCys compared with the respective C groups. In contrast, the expression of the key enzymes of glutathione biosynthesis in the liver was significantly lowered by Se and in particular by Met. Liver Chol concentration was significantly higher in all the Se-supplemented C and M groups than in groups C15 and M15. Plasma Chol was, however, lowered. The uninfluenced expression of sterol-regulatory element-binding protein 2 and of hydroxymethyl-glutaryl-CoA reductase, the increased LDL receptor expression and the reduced expression of the hepatobiliary Chol exporter ATP-binding-cassette-transporter 8 (ABCG8) by Se and/or Met explain these findings. We conclude that the elevation of plasma HCys in rats by Se and Met results from a higher export into plasma. The fact that Se in particular combined with Met increases liver Chol but reduces plasma Chol should be addressed in future investigations focussing on the regulation of ABCG8, which is also selectively involved in the reverse transport of phytosterols in the small intestine.
Impact of climate change on soil erosion and the efficiency of soil conservation practices in Austria
Authors: KLIK A. , EITZINGER J.
Published: March 2010

The goal of the present study was to assess the impact of selected soil protection measures on soil erosion and retention of rainwater in a 1·14 km2 watershed used for agriculture in the north-east of Austria. Watershed conditions under conventional tillage (CT), no-till (NT) and under grassland use were simulated using the Water Erosion Prediction Project (WEPP) soil erosion model. The period 1961–90 was used as a reference and results were compared to future Intergovernmental Panel on Climate Change (IPCC) scenarios A1B and A2 (2040–60).

The simulations for the NT and grassland options suggested runoff would decrease by 38 and 75%, respectively, under the current climatic conditions. The simulation results suggest that, under future climate scenarios, the effectiveness of the selected soil conservation measures with respect to runoff will be similar, or decreased by 16–53%.

The actual average net soil losses in the watershed varied from 2·57 t/ha/yr for conventional soil management systems to 0.01 t/ha/yr for grassland. This corresponds to a maximum average annual loss of about 0·2 mm, which is considered to be the average annual soil formation rate and therefore an acceptable soil loss. The current soil/land use does not exceed this limit, with most of the erosion occurring during spring time. Under future climate scenarios, the simulations suggested that CT would either decrease soil erosion by up to 55% or increase it by up to 56%. Under these conditions, the acceptable limits will partly be exceeded. The simulations of NT suggested this would reduce annual soil loss rates (compared to CT) to 0·2 and 1·4 t/ha, i.e. about the same or slightly higher than for NT under actual conditions. The simulation of conversion to grassland suggested soil erosion was almost completely prevented.

The selected soil conservation methods maintain their protective effect on soil resources, independent of the climate scenario. Therefore, with small adaptations, they can also be recommended as sustainable soil/land management systems under future climatic conditions.

However, based on the available climate scenarios, climate-induced changes in the frequency and intensity of heavy rainstorms were only considered in a limited way in the present work. As the general future trend indicates a strong increase of rainstorms with high intensity during summer months, the results of the present study may be too optimistic.
Pentagon Pictures: The Civil Divide in Norman Mailer's The Armies of the Night
Authors: WILSON ANDREW
Published: March 2010

This paper focusses on Norman Mailer's treatment of the 1967 March on the Pentagon in his Pulitzer Prize-winning work of non-fiction The Armies of the Night. The visual and linguistic properties developed by the author throughout the first book of The Armies of the Night are identified and assessed in relation to the anti-war movements and counterculture temperament of the 1960s. Comparisons are made with post-war writers and earlier North American authors as a means of clarifying “American” aspects of Mailer's handling of his material. Mailer's journalistic techniques, his often spontaneous and engaged responses, are also defined within the context of the social conflicts of the late 1960s.
Lattice Boltzmann simulation of electromechanical resonators in gaseous media
Authors: COLOSQUI CARLOS E. , KARABACAK DEVREZ M. , EKINCI KAMIL L. , YAKHOT VICTOR
Published: March 2010

In this work, we employ a kinetic-theory-based approach to predict the hydrodynamic forces on electromechanical resonators operating in gaseous media. Using the Boltzmann–BGK equation, we investigate the influence of the resonator geometry on the fluid resistance in the entire range of non-dimensional frequency variation 0 ≤ τω ≤ ∞; here the fluid relaxation time τ = μ/p is determined by the gas viscosity μ and pressure p at thermodynamic equilibrium, and ω is the (angular) oscillation frequency. Our results here capture two important aspects of recent experimental measurements that covered a broad range of experimental parameters. First, the experimentally observed transition from viscous to viscoelastic flow in simple gases at τω ≈ 1 emerges naturally in the numerical data. Second, the calculated effects of resonator geometry are in agreement with experimental observations.
Honeydew foraging by birds in tropical montane forests and pastures of Mexico
Authors: Gamper Heather A. , Koptur Suzanne
Published: March 2010

A honeydew-producing scale insect, Stigmacoccus garmilleri (Margarodidae), is associated with oak trees (Quercus spp.) in highland forests of Mexico. Although feeding by ants on scale-insect honeydew is more frequently documented in the literature, the honeydew produced by feeding instars of S. garmilleri is sufficient to provide nourishment for birds. This study elucidates bird use of honeydew in the tropical montane forests near Chiconquiaco, Veracruz, Mexico, and uncovers patterns in honeydew foraging. Over a 2-mo period, 40 trees harbouring scale insects, located in both forest and pasture areas, were intensely studied (160 h of bird-foraging observations along with quantitative measurements of honeydew production). Fifteen resident bird species and 18 migrant species were observed visiting observation trees. Approximately 72% of the resident bird species and 83% of the migrant bird species observed were recorded to forage on scale-insect honeydew. Audubon's warbler (Dendroica coronata auduboni) was the most active consumer and defender of the resource. Of 118 aggressive chases observed, only 9.65% occurred in forest observation trees, and 90.3% in pasture trees. Audubon's warbler demonstrated preferential defence and territorial patrolling of scale-insect honeydew in scattered pasture trees.
Seed dispersal of the Brazil nut tree (Bertholletia excelsa) by scatter-hoarding rodents in a central Amazonian forest
Authors: Haugaasen Joanne M. Tuck , Haugaasen Torbjørn , Peres Carlos A. , Gribel Rogerio , Wegge Per
Published: March 2010

We know surprisingly little about the fate of seeds of the Brazil nut tree (Bertholletia excelsa) under natural conditions. Here we investigate seed removal, predation and caching of Brazil nuts by scatter-hoarding rodents in the wet and dry seasons, based on an experimental approach using 900 thread-marked seeds. We tracked the fate of seeds handled by these animals to examine how seasonal food availability may influence caching rates, dispersal distances and cache longevity. Most seeds exposed to dispersal trials were removed by scatter-hoarders during the first week in both seasons and seeds were generally buried intact in single-seeded caches within 10 m of seed stations. Seeds were removed significantly faster and buried at greater distances during the dry season. The proportion of seeds buried intact was considerably higher in the wet season (74.4%) than in the dry season (38.2%). Most (99.4%) of the 881 primary caches monitored were recovered, but these had a significantly shorter lifetime in the dry season. Our results show that rodents are highly skilled at retrieving buried Brazil nuts and that caching behaviour appears to be affected by seasonal resource abundance. Reduced seed availability due to intensive harvest could potentially create a dry-season scenario where most seeds succumb to pre-dispersal predation, thereby adversely affecting the natural regeneration of Brazil nut trees.
Cognitive architectures and language acquisition: A case study in pronoun comprehension
Authors: VAN RIJ JACOLIEN , VAN RIJN HEDDERIK , HENDRIKS PETRA
Published: March 2010

In this paper we discuss a computational cognitive model of children's poor performance on pronoun interpretation (the so-called Delay of Principle B Effect, or DPBE). This cognitive model is based on a theoretical account that attributes the DPBE to children's inability as hearers to also take into account the speaker's perspective. The cognitive model predicts that child hearers are unable to do so because their speed of linguistic processing is too limited to perform this second step in interpretation. We tested this hypothesis empirically in a psycholinguistic study, in which we slowed down the speech rate to give children more time for interpretation, and in a computational simulation study. The results of the two studies confirm the predictions of our model. Moreover, these studies show that embedding a theory of linguistic competence in a cognitive architecture allows for the generation of detailed and testable predictions with respect to linguistic performance.
The Lifshitz–Slyozov–Wagner equation for reaction-controlled kinetics
Authors: Damialis Apostolos
Published: March 2010

We rigorously derive a weak form of the Lifshitz–Slyozov–Wagner equation as the homogenization limit of a Stefan-type problem describing reaction-controlled coarsening of a large number of small spherical particles. Moreover, we deduce that the effective mean-field description holds true in the particular limit of vanishing surface-area density of particles.
Multiple solutions for a class of quasilinear elliptic equations of p(x)-Laplacian type with nonlinear boundary conditions
Authors: Chung Nguyen Thanh , Ngô Quôc-Anh
Published: March 2010

Using variational methods we study the non-existence and multiplicity of non-negative solutions for a class of quasilinear elliptic equations of p(x)-Laplacian type with nonlinear boundary conditions of the form

where Ω; is a bounded domain with smooth boundary, n is the outer unit normal to ∂Ω and λ is a parameter. Furthermore, we want to emphasize that g : ∂Ω × [0,∞)→ ℝ is a continuous function that may or may not satisfy the Ambrosetti–Rabinowitz-type condition.
Projections of surfaces in the hyperbolic space along horocycles
Authors: Izumiya Shyuichi , Tari Farid
Published: March 2010

We study orthogonal projections of embedded surfaces M in H3+ (−1) along horocycles to planes. The singularities of the projections capture the extrinsic geometry of M related to the lightcone Gauss map. We give geometric characterizations of these singularities and prove a Koenderink-type theorem that relates the hyperbolic curvature of the surface to the curvature of the profile and of the normal section of the surface. We also prove duality results concerning the bifurcation set of the family of projections.
Continuous families of exponential attractors for singularly perturbed equations with memory
Authors: Gatti Stefania , Miranville Alain , Pata Vittorino , Zelik Sergey
Published: March 2010

For a family of semigroups Sε(t) : ℌε → ℌε depending on a perturbation parameter ε ∈ [0, 1], where the perturbation is allowed to become singular at ε = 0, we establish a general theorem on the existence of exponential attractors εε satisfying a suitable Hölder continuity property with respect to the symmetric Hausdorff distance at every ε ∈ [0, 1]. The result is applied to the abstract evolution equations with memory

where kε(s) = (1/ε)k(s/ε) is the rescaling of a convex summable kernel k with unit mass. Such a family can be viewed as a memory perturbation of the equation

formally obtained in the singular limit ε → 0.
A quasilinear problem without the Ambrosetti–Rabinowitz-type condition
Authors: Iturriaga Leonelo , Lorca Sebastián , Ubilla Pedro
Published: March 2010

We study the existence of a positive solution of a p-superlinear equation involving the p-Laplacian operator. The main difficulty here is that the nonlinearity considered does not necessarily verify the well-known Ambrosetti–Rabinowitz condition. As an application, by performing an adequate change of variables we obtain an existence result of a quasilinear equation depending on the gradient.
The domain of analyticity of Dirichlet–Neumann operators
Authors: Hu Bei , Nicholls David P.
Published: March 2010

Dirichlet–Neumann operators arise in many applications in the sciences, and this has inspired a number of studies on their analytical properties. In this paper we further investigate the analyticity properties of Dirichlet–Neumann operators as functions of the boundary shape. In particular, we study the size of the disc of convergence of their Taylor-series representation. For this we use a complexification technique which requires a novel reformulation of the problem, coupled with methods for systems of elliptic partial differential equations. Numerical results to illustrate our theoretical conclusions are presented.