bluuebunny/crossref_metadata_2025 huggingface dataset:
The Coordination Chemistry of FeCl3and FeCl2to Bis[2‐(2,3‐dihydroxyphenyl)‐6‐pyridylmethyl](2‐pyridylmethyl)amine: Access to a Diiron(III) Compound with an Unusual Pentagonal‐Bipyramidal/Square‐Pyramidal Environment
Authors: Machkour Ahmed , Thallaj Nasser K. , Benhamou Laila , Lachkar Mohammed , Mandon Dominique
Published: June 2006

Coordination of FeCl3to the title ligand yields a mononuclear iron(III) complex1, which was characterized by spectroscopic techniques and X‐ray diffraction. The ligand is (κ3‐N) tridentate and the metal, which lies in a pseudo‐octahedral environment, is bound to a phenolate group from the catechol substituent. The dichloroiron(II) complex2was easily obtained by metalation of the ligand with FeCl2and characterized by various spectroscopic techniques. In their cyclic voltammograms both1and2display the same reversible FeII/FeIIIwave atE1/2=10 mV (vs. SCE). Reduction of compound1with Zn/Hg yields2′, which displays identical properties to2. Taken together, these findings indicate that in spite of the different oxidation state of the metal in2, no major geometrical/structural change is observed at the metal center with respect to1. The reaction of2with dioxygen in the absence of organic substrates proceeds extremely rapidly and yields compound3, which is a diiron(III) derivative whose X‐ray crystal structure is also reported. The possibility of a radical‐based mechanism is discussed. Compound3displays an unusual geometry: one iron(III) center is seven‐coordinate, whereas the other lies in a square‐pyramidal environment. The two iron atoms are bridged by the catecholato substituents. To the best of our knowledge,3is the first example of a seven‐coordinate iron(III) derivative with tris(2‐pyridylmethyl)amine ligands.
Adsorption and Dynamics of Long‐Range Interacting Fullerenes in a Flexible, Two‐Dimensional, Nanoporous Porphyrin Network
Authors: Kiebele Andreas , Bonifazi Davide , Cheng Fuyong , Stöhr Meike , Diederich François , Jung Thomas , Spillmann Hannes
Published: June 2006

Herein, a detailed investigation of the adsorption and dynamics of C60 and C70 fullerenes hosted in a self‐assembled, two‐dimensional, nanoporous porphyrin network on a solid Ag surface is presented. Time‐resolved scanning tunneling microscopy (STM) studies of these supramolecular systems at the molecular scale reveal distinct host–guest interactions giving rise to a pronounced dissimilar mobility of the two fullerenes within the porphyrin network. Furthermore, long‐range coverage‐dependent interactions between the all‐carbon guests, which clearly affect their mobility and are likely mediated by a complex mechanism involving the Ag substrate and the flexible porphyrin host network, are observed. At increased fullerene coverage, this unprecedented interplay results in the formation of large fullerene chains and islands. By applying a lattice gas model with nearest‐neighbor interactions and by evaluating the fullerene‐pair distribution functions, the respective coverage‐dependent guest–guest interaction energies are estimated.
Außenputz auf Leichtmauerwerk – Vermeiden schädlicher Risse
Authors: Schubert Peter
Published: June 2006

Außenputz auf Leichtmauerwerk – Vermeiden schädlicher Risse
Risse im Außenputz, durch die Wasser in die Außenwand eindringen kann – also schädliche Risse, Rißbreite etwa über 0,2 mm –, sind unbedingt zu vermeiden. Derartige Risse können durch verschiedene Ursachen hervorgerufen werden. Sie lassen sich Ursachengruppen zuordnen. Einzelrisse im Putzgrund müssen i. w. durch konstruktive Maßnahmen vermieden werden. Die sach‐ und normgerechte Ausführung des Putzgrundes ist eine weitere wichtige Voraussetzung für das Vermeiden schädlicher Risse im Außenputz. Dieser muß in seinen Eigenschaften besonders an den Putzgrund Leichtmauerwerk angepaßt sein. Um dies zu gewährleisten, müssen die relevanten Eigenschaften von Putz und Putzgrund bekannt sein oder durch Prüfung ermittelt werden. Derzeit verfügbare Eigenschaftswerte und Eigenschaftszusammenhänge wurden ausgewertet und bewertet sowie geeignete Prüfverfahren angegeben. Die Rißsicherheit kann näherungsweise mit Hilfe von Rißkriterien beurteilt werden, die vorgestellt und erläutert werden. Mit dem heute wesentlich erweiterten und verbesserten Erkenntnis‐ und Erfahrungsstand lassen sich schädliche Risse im Außenputz, die auf einen für den jeweiligen Putzgrund ungeeigneten Putz zurückzuführen sind, noch sehr viel sicherer vermeiden als bisher.
Zur Haftscherfestigkeit bei Mauerwerk aus Leichtbetonsteinen
Authors: Glitza Horst , Jäger Wolfram , Burkert Toralf
Published: June 2006

Die Anforderungswerte für Haftscherfestigkeit im Anhang A von DIN 1053‐1 beziehen sich auf das Prüfverfahren nach DIN 18555‐5 unter Verwendung eines Kalksandsteins als Referenzstein. In der Literatur werden für Leichtbetonsteine demgegenüber deutlich höhere Haftscherfestigkeiten angegeben. Die dort zu findenden Werte sind jedoch teilweise mit sehr großen Streuungen behaftet. Im Beitrag wird den Ursachen hierfür nachgegangen und ein Vorschlag für eine Anpassung der Anforderungs‐ und Rechenwerte für Mauerwerk aus Leichtbetonsteinen im Rahmen der derzeit laufenden Überarbeitung der DIN 1053‐1 unterbreitet.
Eigenschaftswerte von Kalksandsteinen unter Zugbeanspruchung
Authors: Schubert Peter , Graubohm Markus
Published: June 2006

Die Zug‐ bzw. Biegezugfestigkeit von Mauersteinen beeinflußt die Zug‐, Biegezug‐ und Schubfestigkeit von Mauerwerk i. d. R. entscheidend. Die für die Mauerwerkbemessung in DIN 1053‐1 zugrunde gelegten Eigenschaftswerte der Mauersteine sind stark pauschaliert und stammen aus über 10 Jahre alten Untersuchungen. Für die Überarbeitung der DIN 1053‐1 bzw. das Anwendungsdokument zu Eurocode 6 ist eine aktualisierte Auswertung und Bewertung der derzeit verfügbaren Untersuchungsergebnisse erforderlich. Dies ist Inhalt des Beitrages. Die Untersuchungsergebnisse werden statistisch ausgewertet, in Diagrammen sowie Tabellen dargestellt und für die Anwendung in den Technischen Regelwerken aufbereitet.
Sugar‐Derived Ras Inhibitors: Group Epitope Mapping by NMR Spectroscopy and Biological Evaluation
Authors: Peri Francesco , Airoldi Cristina , Colombo Sonia , Mari Silvia , Jiménez‐Barbero Jesús , Martegani Enzo , Nicotra Francesco
Published: June 2006

Novel inhibitors of Ras protein activation have been found, containing a bicyclic core derived from D‐arabinose and benzyl and phenylhydroxylamine moieties. NMR studies (trNOE, saturation‐transfer difference, STD) of the binding between these molecules and human p21 h‐Ras are reported. A pharmacophore mapping indicates that both the benzyl and the phenylhydroxylamine moieties are essential for protein binding. Molecules lacking one of these groups were synthesized and tested to confirm this hypothesis, and no interaction with Ras in vitro, nor biological activity in mammalian cells was observed. Our studies led to the development of molecules that selectively inhibit Ras‐dependent cellular growth in mammalian cells. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Cationic Rhodium(I)/Modified‐BINAP Catalyzed [2+2+2] Cycloaddition of Alkynes with Nitriles
Authors: Tanaka Ken , Suzuki Nanami , Nishida Goushi
Published: June 2006

Cationic rhodium(I)/modified‐BINAP complexes catalyze a chemo‐ and regioselective [2+2+2] cycloaddition of a wide variety of alkynes and nitriles leading to highly functionalized pyridines under mild reaction conditions. The asymmetric variant of this reaction, enantioselective desymmetrization of substituted malononitriles, also proceeded to give enantio‐enriched bicyclic pyridines which possess a tertiary or quaternary stereocenter. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Volatile constituents of Ailanthus excelsa Roxb.
Authors: Tzakou Olga , Said Ataa , Farag Ahmed , Rashed Khaled
Published: June 2006

The volatile constituents from fresh aerial parts of Ailanthus excelsa were analysed by GC and GC–MS. Fatty acids and their esters represented the main fraction (40.9%) of the obtained oil, with 9,12,15‐octadecatrienoic acid methyl ester (linolenic acid) being the main component (13.7%). The dominant component of the oil was phytol (26.7%). Copyright © 2006 John Wiley & Sons, Ltd.
Primary beer fermentation by immobilised yeast—a review on flavour formation and control strategies
Authors: Willaert Ronnie , Nedovic Viktor A
Published: June 2006

Immobilised cells are increasingly being used in bio‐industries and may also have benefits for the brewing industry. The major challenge to applying this technology successfully in breweries is focused on the main fermentation in combination with the secondary fermentation. In particular, the control and fine‐tuning of the flavour profile during the main fermentation require further investigation. In this review, the influence of immobilised cell technology on the production of the flavour‐active compounds (i.e. higher alcohols, esters and vicinal diketones) is discussed. Control strategies that are based on the manipulation of parameters during fermentation such as temperature, feed volume, wort gravity, wort composition and aeration are explained. Finally, bioreactor configurations that may facilitate immobilised cells in performing the primary fermentation are evaluated. Copyright © 2006 Society of Chemical Industry
Study of a continuous reactor for selective solvent extraction of haemorphins in the course of peptic haemoglobin hydrolysis
Authors: Froidevaux Renato , Vercaigne‐Marko Dominique , Kapel Romain , Lecouturier Didier , Chung Sookhyun , Dhulster Pascal , Guillochon Didier
Published: June 2006

The continuous hydrolysis of bovine haemoglobin at pH 3 in a triphasic reactor was studied in order to prepare two pure transient and hydrophobic opioid peptides in one step. A continuous stirred‐tank reactor was designed to extract continuously and selectively LVV‐haemorphin‐7 and VV‐haemorphin‐7 by a butan‐2‐ol–octan‐1‐ol mixture in the course of bovine haemoglobin hydrolysis by pepsin immobilised on A568 Duolite resin. The residence time in the aqueous and organic phases was maintained at 1 h. This system allowed a steady state to be achieved for haemorphin concentrations in each phase and the pepsin stability to be maintained. Finally, success was achieved in producing and extracting continuously the two haemorphins in the aqueous/butan‐2‐ol–octan‐1‐ol biphasic medium for more than 10 bed volumes of the reactor. Copyright © 2006 Society of Chemical Industry
High resolution 3T MRI for the assessment of cervical and superficial cranial arteries in giant cell arteritis
Authors: Markl Michael , Uhl Markus , Wieben Oliver , Neß Thomas , Langer Mathias , Hennig Jürgen , Bley Thorsten A.
Published: June 2006

A new high‐resolution MR protocol for the combined assessment of neurovascular arterial anatomy and subsequent evaluation of inflammatory disease in cranial vessels walls has been investigated. First‐pass contrast‐enhanced MR angiography (CE‐MRA) in combination with parallel imaging at high field permits the depiction of the neurovascular geometry with large coverage, including the aortic arch, supraaortic vessels, and almost the entire head, with high, submillimeter detail. Utilizing the remaining contrast agent, postcontrast T1‐weighted turbo spin‐echo (TSE) imaging was used to generate late enhancement images of the vessel walls to assess the morphology and potential inflammatory changes in cranial arteries with high in‐plane (195 × 260 μm2) spatial resolution. As a result, a combined analysis of neurovascular arterial anatomy as well as cranial vessel wall inflammations could be achieved in less than 45 minutes in all studies. The feasibility and clinical value for the diagnosis of rheumatologic diseases and simultaneous arteriosclerotic involvement was demonstrated in seven patients with suspected giant cell arteritis (GCA). Excellent CE‐MRA image quality could be achieved and even vascular geometry of small superficial cranial arteries could be successfully visualized using single dose (0.1 mmol/kg) contrast agent administration and a dedicated phased‐array head and neck coil at 3T. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Organizational identity strength, identification, and commitment and their relationships to turnover intention: does organizational hierarchy matter?
Authors: Cole Michael S. , Bruch Heike
Published: June 2006

In the present study we sought to clarify the functional distinctions between organization identity strength, organizational identification, and organizational commitment. Data were obtained from 10 948 employees of a large steel manufacturer. First, confirmatory factor analysis was used to test the discriminant validity of the three focal constructs. Next, drawing on research that suggests hierarchical differentiation may influence individuals' conceptual frame of reference, we examined each focal construct's measurement equivalence across three hierarchical levels (officers, n = 1,056, middle‐management, n = 1049, workers, n = 1050). Finally, multigroup structural equation modeling was used to simultaneously estimate the between‐group correlations between turnover intention and organization identity strength, organizational identification, and organizational commitment. Results indicated that (a) the measures used to reflect the three focal constructs were empirically distinct, (b) the focal constructs were conceptually equivalent across hierarchical levels, and (c) the pattern of correlations with turnover intention was different for employees with management responsibilities versus workers with no management responsibility. The present findings suggest perceptions of a strong organizational identity, organizational identification, and organizational commitment may influence employees' turnover intention in unique ways, depending on their hierarchical level within the organization. Copyright © 2006 John Wiley & Sons, Ltd.
Social identities and commitments at work: toward an integrative model
Authors: Meyer John P. , Becker Thomas E. , van Dick Rolf
Published: June 2006

Although social identities and work‐related commitment are important aspects of employee attachment, distinctions between and relations among the two have not been clearly articulated. In this conceptual piece, we propose that identity and commitment are distinguishable in terms of their essential meaning, foci of attachment, mindsets, volitionality, and behavioral implications. We further suggest that situated and deep structure social identities are differentially antecedent to exchange‐based and value‐based commitments, and that commitment mediates, at least partially, the effects of identities on motivation and work behavior. Finally, we consider the implications of multiple identities for employees in different kinds of collectives (nested and cross‐cutting). Copyright © 2006 John Wiley & Sons, Ltd.
Modeling ferricyanide adsorption on goethite: Basics and applications
Authors: Rennert Thilo , Mansfeldt Tim
Published: June 2006

Ferricyanide, [FeIII(CN)6]3–, is an anthropogenic and potentially toxic contaminant in soil. Its adsorption on goethite has been previously studied, but not evaluated with a surface complexation model (SCM) considering the effects of pH and ionic strength. Therefore, we carried out batch experiments with ferricyanide and goethite suspensions with different ferricyanide concentrations (0.075 mM and 0.15 mM), ionic strengths (0.01 and 0.1 M), and pH (ranging from 4 to 7.4). Adsorption data were then interpreted with the 1‐pK Stern and the charge distribution model assuming monodentate inner‐sphere ferricyanide surface complexes on goethite (lg K = 10.6), which are known from infrared spectroscopy. Furthermore, we applied the SCM to ferricyanide adsorption in previous studies on ferricyanide adsorption in the presence of sulfate and on the solubility of Fe‐cyanide complexes in a suspension of a loess loam. The SCM correctly reflected ferricyanide adsorption in the batch experiments as well as the effects of pH and ionic strength. The SCM also described ferricyanide adsorption in the presence of sulfate, because the ferricyanide adsorption measured and that modeled were significantly correlated (R2 = 0.80). Furthermore, we applied the SCM to a study on the solubility of Fe‐cyanide complexes in soil under varying redox conditions so that ferricyanide adsorption on goethite and precipitation of Fe‐cyanide complexes were considered. The actual ferricyanide concentrations were rather reflected when applying the SCM compared to those modeled in an approach in which exclusively precipitation was taken into account. We conclude that ferricyanide adsorption on goethite should be included into geochemical modeling approaches on the mobility of Fe‐cyanide complexes in subsoils.
Black carbon in the zonal steppe soils of Russia
Authors: Rodionov Andrej , Amelung Wulf , Haumaier Ludwig , Urusevskaja Inga , Zech Wolfgang
Published: June 2006

Black Mollisols are typically rich in charred organic matter, however, little is known about the zonal distribution of black C (BC) in steppe soils. In this study, we used benzene polycarboxylic acids (BPCA) as specific markers for BC in particle‐size fractions of depth profiles in several zonal soils (Greyzem, Phaeozem, Chernozem, Kastanozem) of the Russian steppe. In addition, liquid‐state 13C‐NMR spectra were obtained on the alkaline‐soluble soil organic matter (SOM). The results showed that both the content and depth distribution of BC varies in the different soil types; the concentration of BC in the bulk top soils being closely related to the aromaticity of the SOM (r2 = 0.98 for the native topsoils, 0.83 for top‐ and subsurface soils). Especially the Chernozems were rich in aromatic SOM, which partly contained more than 17% BC of total C, most of which being allocated in the mineral fractions. Long‐term arable cropping did not reduce the BC contents of the surface soil, though it did promote the enrichment of BC in the silt fractions. The same shift was detected as soil depth increased. We conclude that BC is not fully inert in these soils, but apparently can be preserved in the silt as decomposition of SOM increased, i.e., it accumulates exactly in that fraction, which has been formerly assigned to contain old, aromatic C.
Soil mapping for land‐use planning in a karst area of N Thailand with due consideration of local knowledge
Authors: Schuler Ulrich , Choocharoen Chalathon , Elstner Peter , Neef Andreas , Stahr Karl , Zarei Mehdi , Herrmann Ludger
Published: June 2006

For the development of sustainable land‐management systems in the highlands of N Thailand, detailed knowledge about soil distribution and soil properties is a prerequisite. Yet to date, there are hardly any detailed soil maps available on a watershed scale.

In this study, soil maps on watershed level were evaluated with regard to their suitability for agricultural land‐use planning. In addition to common scientific methods (as underlying the WRB classification), participatory methods were used to exploit local knowledge about soils and to document it in a “Local Soil Map”.

Where the WRB classification identified eight soil units, the farmers distinguished only five on the basis of soil color and “hardness”. The “Local Soil Map” shows little resemblance with the detailed, patchy pattern of the WRB‐based soil map. On the contrary, the “Local Soil Map” is fairly similar to the petrographic map suggesting that soil color is directly related to parent material.

The farmers' perception about soil fertility and soil suitability for cropping could be confirmed by analytical data. We conclude that integrating local soil knowledge, petrographic information, and knowledge of local cropping practices allows for a rapid compilation of information for land‐evaluation purposes at watershed level. It is the most efficient way to build a base for regional land‐use planning.
Rheological‐stiffness analysis of K+‐treated and CaCO3‐rich soils
Authors: Markgraf Wibke , Horn Rainer
Published: June 2006

Rheological methods are applied whenever flow behavior of substances needs to be investigated on a particle‐to‐particle scale executed by a parallel‐plate rheometer. Under oscillation, mechanical effects due to trafficking or vibrations caused by agricultural and forest machinery can be simulated by conducting amplitude‐sweep tests. Hooke's law of elasticity, Newton's law for ideal fluids (viscosity), Mohr‐Coulomb's equation, and, finally, Bingham's yielding are well‐known relationships and parameters in the field of rheology. This paper aims to introduce rheometry as a suitable method to determine the mechanical behavior of salt‐affected soils when subjected to external stresses. Potassium‐treated loamy sand from Halle and loamy silt from Kassel, both sites located in Germany, as well as loess from Israel, saturated with NaCl solutions in several concentrations were analyzed. From the stress‐strain–relationship parameters like the storage modulus G′ and the loss modulus G″, yield stress τy and the linear viscoelastic (LVE)–deformation range including the deformation limit γL, i.e., the transition from an elastic to a viscous state, were determined and calculated, respectively. With respect to salt effects, amplitude‐sweep tests on originally CaCO3‐rich Avdat Loess show an increasing stability if saturated with higher NaCl concentrations. Comparable tests with K+‐rich substrates from Halle and Kassel evinced similar tendencies including the phenomenon of a critical K+ content, which becomes more obvious in case of the drained (–60h Pa) loamy‐silt samples from Kassel. Nevertheless, a higher microstructural stability is given in both substrates from Halle and Kassel, affected by different water contents, in general, which influence the exchange and availability of cations. The results verify that oscillatory tests are applicable for retracing salt‐induced effects, beside those ones, which are influenced by texture, current water content, and/or further chemical parameters.
Methods for evaluating human impact on soil microorganisms based on their activity, biomass, and diversity in agricultural soils
Authors: Joergensen Rainer Georg , Emmerling Christoph
Published: June 2006

The present review is focused on microbiological methods used in agricultural soils accustomed to human disturbance. Recent developments in soil biology are analyzed with the aim of highlighting gaps in knowledge, unsolved research questions, and controversial results. Activity rates (basal respiration, N mineralization) and biomass are used as overall indices for assessing microbial functions in soil and can be supplemented by biomass ratios (C : N, C : P, and C : S) and eco‐physiological ratios (soil organic C : microbial‐biomass C, qCO2, qNmin). The community structure can be characterized by functional groups of the soil microbial biomass such as fungi and bacteria, Gram‐negative and Gram‐positive bacteria, or by biotic diversity. Methodological aspects of soil microbial indices are assessed, such as sampling, pretreatment of samples, and conversion factors of data into biomass values. Microbial‐biomass C (µg (g soil)–1) can be estimated by multiplying total PLFA (nmol (g soil)–1) by the FPLFA‐factor of 5.8 and DNA (µg (g soil)–1) by the FDNA‐factor of 6.0. In addition, the turnover of the soil microbial biomass is appreciated as a key process for maintaining nutrient cycles in soil. Examples are briefly presented that show the direction of human impact on soil microorganisms by the methods evaluated. These examples are taken from research on organic farming, reduced tillage, de‐intensification of land‐use management, degradation of peatland, slurry application, salinization, heavy‐metal contamination, lignite deposition, pesticide application, antibiotics, TNT, and genetically modified plants.
The mechanical behavior of structured and homogenized soil under repeated loading
Authors: Peth Stephan , Horn Rainer
Published: June 2006

Soil deformation is increasingly important in crop production since nowadays weights of agricultural machines exceed the bearing capacity of most soils. Often this is counteracted by distributing the weight over more axles leading to an increase in wheeling frequency. Machine passages during one year can, depending on the crop and equipment used, range between two and five times for the majority of the field and up to twenty times and more for a wheeling track. These add up to hundreds of loading events for a crop‐rotation period. In this study, we investigated the effect of multiple loading with the same load in a cyclic‐compression test on soil‐pore‐volume change. The tests were conducted on homogenized soil samples with varying texture and undisturbed soil samples from a field experimental site comparing conventional and conservation‐tillage systems. Of particular interest was the question whether there is significant plastic soil deformation for soil stresses that remained sufficiently below the precompression stress, which is commonly neglected. Our results show that especially for cohesive soils, the assumption of fully elasticity in the recompression range may not be justified since those soils show distinct cyclic‐creep behavior. We found that deformation under cyclic loading follows a logarithmic law. We used the slope of the logarithmic fit of void‐ratio changes vs. loading cycles as a parameter to characterize the sensitivity of soils to cyclic compression. The results suggest that for characterizing the mechanical stability of soils that show cyclic creep, we have (with respect to long‐term deformation effects) to consider both precompression stress and cyclic compressibility.
Topsoil characterization—recommendations for revision and expansion of the FAO‐Draft (1998) with emphasis on humus forms and biological features
Authors: Broll Gabriele , Brauckmann Hans‐Jörg , Overesch Mark , Junge Birte , Erber Claudia , Milbert Gerhard , Baize Denis , Nachtergaele Freddy
Published: June 2006

The characterization of topsoils has recently received enhanced attention, particularly for environmental monitoring. Traditional national and international soil taxonomies hardly consider the topsoil in spite of its importance for soil quality. Consequently, the FAO “Topsoil Characterization for Sustainable Land Management” was developed to be used additionally for describing topsoils and to combine it with the “World Reference Base for Soil Resources” (WRB). In this paper, recommendations for a first step of a revision and expansion of the FAO “Topsoil Characterization” are made. On the one hand, common rules for soil description as used in the FAO “Guidelines for Profile Description” were incorporated in the FAO “Topsoil Characterization”. On the other hand, new characteristics for the description of the organic matter and of biological features of the topsoils were introduced. At first, the proposed German systematics of humus forms is presented and correlated with different national systematics, for validation in the international context. Secondly, a correlation of the new German systematics of humus forms with the FAO “Topsoil Characterization for Sustainable Land Management” and other topsoil systematics is made. Thirdly, additional qualifiers are described focussing on the organic layers and the biological features.

A coincidence between the characterization of humus forms and topsoils was found which appears to be an appropriate basis for the incorporation of humus forms in the FAO “Topsoil Characterization”. Investigations have shown that the topsoils in forests can be described comprehensively by additional qualifiers for the organic layers. Grassland or arable land which usually lack organic layers can be characterized in detail by qualifiers concerning soil biological activity in the A horizon. The methodology was already applied successfully in temperate regions. But there is still a need for further discussion of the revision and for tests in tropical and subtropical zones and poorly drained areas.
Silicon pools and fluxes in soils and landscapes—a review
Authors: Sommer Michael , Kaczorek Danuta , Kuzyakov Yakov , Breuer Jörn
Published: June 2006

Silicon (Si) is the second‐most abundant element in the earth's crust. In the pedosphere, however, huge spans of Si contents occur mainly caused by Si redistribution in soil profiles and landscapes. Here, we summarize the current knowledge on the different pools and fluxes of Si in soils and terrestrial biogeosystems. Weathering and subsequent release of soluble Si may lead to (1) secondarily bound Si in newly formed Al silicates, (2) amorphous silica precipitation on surfaces of other minerals, (3) plant uptake, formation of phytogenic Si, and subsequent retranslocation to soils, (4) translocation within soil profiles and formation of new horizons, or (5) translocation out of soils (desilication). The research carried out hitherto focused on the participation of Si in weathering processes, especially in clay neoformation, buffering mechanisms for acids in soils or chemical denudation of landscapes. There are, however, only few investigations on the characteristics and controls of the low‐crystalline, almost pure silica compounds formed during pedogenesis. Further, there is strong demand to improve the knowledge of (micro)biological and rhizosphere processes contributing to Si mobilization, plant uptake, and formation of phytogenic Si in plants, and release due to microbial decomposition. The contribution of the biogenic Si sources to Si redistribution within soil profiles and desilication remains unknown concerning the pools, rates, processes, and driving forces. Comprehensive studies considering soil hydrological, chemical, and biological processes as well as their interactions at the scale of pedons and landscapes are necessary to make up and model the Si balance and to couple terrestrial processes with Si cycle of limnic, fluvial, or marine biogeosystems.
Problems in CEC determination of calcareous clayey sediments using the ammonium acetate method
Authors: Dohrmann Reiner
Published: June 2006

Cation‐exchange–capacity (CEC) results of calcareous soils and clays can be erroneous if the ammonium acetate method is used. In this study, a model is proposed to explain the process for systematic underestimation of the CEC. Seven clayey sediments from Germany with varying calcite and low organic‐C content were studied. After several exchange treatments with concentrated ammonium acetate (NH4Ac) solutions, the exchange population is assumed to be in homoionic ammonium form. Throughout the cation‐exchange experiment, calcite reacts with the NH4Ac exchange solution generating Ca2+ cations. During the necessary washing steps to remove excess salt, calcite dissolution is lower but still occurs. The permanently added Ca2+ ions compete successfully with NH$ _4^+ $, especially during the washing steps. This leads to a more or less partial biionic exchange population resulting in an underestimation of the CEC which is calculated based on NH$ _4^+ $ concentration of the clay by Kjeldahl analysis. The biionic exchange population was proven using the new silver thiourea technique with presaturation of calcite, AgTUcalcite. The clay with 148 g kg–1 calcite had a fraction of 16.4 cmol+ kg–1 exchangeable Ca2+. This is ca. 50% of the CEC of this clay being 31.8 cmol+ kg–1. For clays with similar mineralogical composition, this trend is proportional to the calcite content.
Ordered Microporous Surface Films Formed by Core‐Shell‐Type Nanospheres
Authors: Ishizu Koji , Kobayakawa Naoyuki , Uchida Satoshi
Published: June 2006

Summary: Polymer nanospheres are synthesized by free‐radical dispersion copolymerization of methyl methacrylate (MMA) and ethylene glycol dimethacrylate (EGDM) with a methacryloyl‐terminated polystyrene (PS‐MC) macromonomer in cyclohexane. Such polymer nanospheres are stabilized sterically with polystyrene (PS)‐grafted chains in cyclohexane at temperatures greater than 34 °C (the Θ temperature for PS). Ordered microporous surface films are constructed by casting these core‐shell‐type nanospheres from hot cyclohexane solution at 20 °C. The results indicate the possibility of fixation or encapsulation of functional materials after microporous patterning of the core‐shell‐type nanospheres.

SEM photograph of a vertical section of a hexagonal micropore film obtained here.

magnified image

SEM photograph of a vertical section of a hexagonal micropore film obtained here.
Time dependence of 3He diffusion in the human lung: Measurement in the long‐time regime using stimulated echoes
Authors: Wang Chengbo , Miller G. Wilson , Altes Talissa A. , de Lange Eduard E. , Cates Jr. Gordon D. , Mugler John P.
Published: June 2006

A stimulated‐echo‐based technique was developed to measure the long‐time‐scale apparent diffusion coefficient (ADC) of hyperpolarized 3He during a single breath‐hold acquisition. Computer simulations were used to evaluate the performance of the technique and guide the selection of appropriate parameter values for obtaining accurate ADC values. The technique was used in 10 healthy subjects and two subjects with chronic obstructive pulmonary disease (COPD) to measure the global ADC for diffusion times between a few tenths of a second and several seconds, and to acquire spatial maps of the ADC for a diffusion time of 1.5 s. The reproducibility of the technique and its sensitivity to the direction of diffusion sensitization were also investigated. In healthy subjects, global ADC values decreased by severalfold over the range of diffusion times measured (mean values = 0.039 and 0.023 cm2/s at diffusion times of 0.61 and 1.54 s, respectively). ADC maps were generally uniform, with mean values similar to the corresponding global values. For the two COPD subjects, global ADC values were substantially greater than those of every healthy subject at all diffusion times measured. In addition, regional elevations of ADC values were far more conspicuous on long‐time‐scale ADC maps than on short‐time‐scale ADC maps. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Limits on activation‐induced temperature and metabolic changes in the human primary visual cortex
Authors: Katz‐Brull Rachel , Alsop David C. , Marquis Robert P. , Lenkinski Robert E.
Published: June 2006

Changes in cerebral blood flow (CBF) and metabolism are now widely used to map and quantify neural activity, although the underlying mechanism for these changes is still incompletely understood. Magnetic resonance spectroscopy (MRS) at 3T, synchronized with a 32‐s block design visual stimulation paradigm, was employed to investigate activation‐induced changes in temperature and metabolism in the human primary visual cortex. A marginally significant increase in the local temperature of the visual cortex was found (0.1°C, P = 0.09), excluding the possibility of a temperature decrease (95% confidence interval (CI) = 0.0–0.2°C), which was previously suggested. A comparison with models of thermal equilibrium in the presence of blood flow suggests that an increase in heat production during activation, greater than or at least equal to that produced by the complete oxidative metabolism of the elevated glucose (Glc) utilization accompanying activation, would be required to offset the cooling effects of the increased blood flow. The total pools of glutamate (Glu), glutamine (Gln), myo‐Inositol (mI), N‐acetylaspartate (NAA), choline (Cho), and lactate (Lac) were not significantly affected by activation. Limits on Lac concentration changes were too weak to constrain theories of the metabolic use of elevated Glc consumption during stimulation, and emphasize the challenges of measuring even large Lac changes accompanying stimulation. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Pharmakologie der Diuretika: Angriffspunkte der verschiedenen Wirkstoffgruppen
Authors: Knauf Heinrich , Mutschler Ernst
Published: June 2006

Diuretika als harntreibende Arzneistoffe wurden zunächst klinisch‐pharmakologisch nach dem Ausmaß der Diuresesteigerung und der Dosis‐Abhängigkeit ihrer Wirkung eingeteilt. Demgemäß unterschied man High‐ceiling‐von Low‐ceiling‐Diuretika, wobei der Begriff Ceiling (“Decke”) pharmakologisch die maximal erreichbare Wirkstärke (intrinsische Aktivität) des Arzneistoffes charakterisiert.
Polypropylene–clay nanocomposites: Influence of low molecular weight polar additives on intercalation and exfoliation behavior
Authors: Ratnayake U.N. , Haworth B.
Published: June 2006

The influence of low molecular weight additives containing polar groups and modified polyolefin‐based compatibilizers on polypropylene (PP)‐clay nanocomposites (PPCN) has been studied, in terms of intercalation and degree of exfoliation achievable by melt‐state mixing processes. PPCN were prepared by melt mixing two PP homopolymers with organically‐modified montmorillonite type clay, in the presence of maleic anhydride‐grafted polypropylene (PP‐MA) compatibilizer. XRD analysis shows that interlayer spacing of clay has been increased dramatically, while TEM results show a significant improvement of clay dispersion in the PP matrix, when nanocomposites are prepared with commercial PP containing short‐chain organic additives with polar end groups. Subsequent studies based upon customized PP formulations, with amide‐type slip additive, confirm the intercalation of this additive into the clay galleries and its positive and significant impact on clay dispersion. Contact angle measurements suggest that these additives diffuse into the clay gallery space rather than migrating away from the bulk of the PPCN matrix. The interaction between polar group (NH2) of this additive and the polar sites on the filler surface appears to be the driving force for the intercalation. POLYM. ENG. SCI. 46:1008–1015, 2006. © 2006 Society of Plastics Engineers
Characterization and mechanical properties of poly(lactic acid)/poly(ϵ‐caprolactone)/organoclay nanocomposites prepared by melt compounding
Authors: Hasook Aniwat , Tanoue Shuichi , Iemoto Yoshiyuki , Unryu Tsunemune
Published: June 2006

This study investigates the preparation, characterization, and mechanical properties of nanocomposites prepared from poly(lactic acid) (PLA), an organoclay, hereafter referred to as Clay, and poly(ε‐caprolactone) (PCL) by melt compounding in a co‐rotating type, twin screw extruder. The molecular weight of the PCL used was 10K, 40K, or 70–100K. Tensile test data show that the Young's modulus of the PLA/Clay nanocomposite was about 19% higher than that of neat PLA. The tensile strength of the PLA/PCL(10K and 40K)/Clay nanocomposites was about 17% higher than that of neat PLA. On the other hand, the tensile strength of the PLA/PCL(70–100K)/Clay sample was about 7% lower than that of neat PLA. The elongation of the PLA/PCL/Clay composite also improved. The effect of d‐spacing, resulting from adding PCL to the PLA/Clay nanocomposite, depends on the molecular weight of the PCL. The size of the clay agglomerates in the PLA/PCL/Clay nanocomposites is larger than those found in the PLA/Clay. Furthermore, the thermal stability of the PLA/Clay nanocomposite increases with the addition of PCL. On the whole, PCL(10K) was found to be the best additive for PLA/Clay nanocomposites. POLYM. ENG. SCI. 46:1001–1007, 2006. © 2006 Society of Plastics Engineers
Big Five personality development in adolescence and adulthood
Authors: Branje Susan J. T. , van Lieshout Cornelis F. M. , Gerris Jan R. M.
Published: June 2006

The present article examines Big Five personality development across adolescence and middle adulthood. Two adolescents and their fathers and mothers from 285 Dutch families rated their own and their family members' personality. Using accelerated longitudinal growth curve analyses, mean level change in Big Five factors was estimated. For boys, Extraversion and Openness decreased and for girls, Extraversion, Agreeableness, Conscientiousness, and Openness increased. Whereas mothers' Emotional Stability and Conscientiousness increased, fathers' Extraversion, Agreeableness, and Emotional Stability decreased. Differences in self‐ and other‐reported personality change were found, as well as interindividual differences in personality change. Results confirm that personality change is possible across the life course but these changes are not similar for all individuals and depend on the type of observer. Copyright © 2006 John Wiley & Sons, Ltd.
Nanocrystalline dye‐sensitized solar cells having maximum performance
Authors: Kroon J. M. , Bakker N. J. , Smit H. J. P. , Liska P. , Thampi K. R. , Wang P. , Zakeeruddin S. M. , Grätzel M. , Hinsch A. , Hore S. , Würfel U. , Sastrawan R. , Durrant J. R. , Palomares E. , Pettersson H. , Gruszecki T. , Walter J. , Skupien K. , Tulloch G. E.
Published: June 2006

This paper presents an overview of the research carried out by a European consortium with the aim to develop and test new and improved ways to realise dye‐sensitized solar cells (DSC) with enhanced efficiencies and stabilities. Several new areas have been explored in the field of new concepts and materials, fabrication protocols for TiO2 and scatterlayers, metal oxide blocking layers, strategies for co‐sensitization and low temperature processes of platinum deposition. Fundamental understanding of the working principles has been gained by means of electrical and optical modelling and advanced characterization techniques. Cost analyses have been made to demonstrate the potential of DSC as a low cost thin film PV technology. The combined efforts have led to maximum non‐certified power conversion efficiencies under full sunlight of 11% for areas <0ċ2 cm2 and 10ċ1% for a cell with an active area of 1ċ3 cm2. Lifetime studies revealed negligible device degradation after 1000 hrs of accelerated tests under thermal stress at 80°C in the dark and visible light soaking at 60°C. An outlook summarizing future directions in the research and large‐scale production of DSC is presented. Copyright © 2006 John Wiley & Sons, Ltd.
Proteome analysis ofSchizosaccharomyces pombeby two‐dimensional gel electrophoresis and mass spectrometry
Authors: Hwang Kyung‐Hoon , Carapito Christine , Böhmer Susanne , Leize Emmanuelle , Van Dorsselaer Alain , Bernhardt Rita
Published: June 2006

The fission yeastSchizosaccharomyces pombe(S. pombe) is a unicellular eukaryote and contains many genes and regulatory mechanisms that are close to those of mammals. In this study, we performed a global proteomic analysis of the fission yeastS. pombewild type h−SL 972 proteome. More than 1500 protein spots were visualized on silver stained 2‐D gels in the 3–10 pIrange with a high resolution and high reproducibility. Protein identification was carried out by MALDI‐TOF‐MS and/or nanoLC‐MS/MS. Advantage of the complementarity of these two MS approaches was used to enhance the identification quality. So far, 364 proteins (representing 157 different proteins) have been identified. We report here the identification of 117 new proteins on our 2‐D reference map of this yeast compared to the first reference map. Of these identified proteins, 40.1% were involved in metabolism. The present work provides a very useful tool for all studies relying onS. pombeas a model organism and is a considerable complement to the first reference map ofS. pombepublished recently by Sun and coworkers (Sun, N., Jang, J., Lee, S., Kim, S. et al..,Proteomics2005,5, 1574–1579).
Recent progresses in the application of machine learning approach for predicting protein functional class independent of sequence similarity
Authors: Han Lianyi , Cui Juan , Lin Honghuang , Ji Zhiliang , Cao Zhiwei , Li Yixue , Chen Yuzong
Published: June 2006

Protein sequence contains clues to its function. Functional prediction from sequence presents a challenge particularly for proteins that have low or no sequence similarity to proteins of known function. Recently, machine learning methods have been explored for predicting functional class of proteins from sequence‐derived properties independent of sequence similarity, which showed promising potential for low‐ and non‐homologous proteins. These methods can thus be explored as potential tools to complement alignment‐ and clustering‐based methods for predicting protein function. This article reviews the strategies, current progresses, and underlying difficulties in using machine learning methods for predicting the functional class of proteins. The relevant software and web‐servers are described. The reported prediction performances in the application of these methods are also presented, which need to be interpreted with caution as they are dependent on such factors as datasets used and choice of parameters.
Comparative proteome analysis of changes in the 26S proteasome during oocyte maturation in goldfish
Authors: Horiguchi Ryo , Dohra Hideo , Tokumoto Toshinobu
Published: June 2006

Proteasomes are large, multi‐subunit particles that act as the proteolytic machinery for most of the regulated intracellular protein degradation in eukaryotic cells. An alteration of proteasome function may be important for the regulation of the meiotic cell cycle. To study the change at the subunit level of the 26S proteasome during meiotic maturation, we purified 26S proteasomes from immature and mature oocytes of goldfish. Two‐dimensional polyacrylamide gel electrophoresis was used to separate proteins. For differential analysis, whole spots of the 26S proteasome from goldfish oocytes were identified by matrix‐assisted laser desorption/ionization‐time of flight mass spectrometry and database analysis. Four spots that were different (only detected in mature oocyte 265 proteasomes and not in immature ones) and four protein spots that were up‐ or down‐regulated were identified unambiguously. The mature‐specific spots were not 26S proteasome components but rather their interacting proteins, and were identified as chaperonin‐containing TCP‐1 subunits and myosin light chain. Minor spots of three subunits of the 20S core particle and one of the 19S regulatory particle showed meiotic cell cycle‐dependent changes. These results demonstrate that modifications of proteasomal subunits and cell cycle phase‐dependent interactions of proteins with proteasomes occur during oocyte maturation in goldfish.
Proteomic analysis of antigens from Leishmania infantum promastigotes
Authors: Dea‐Ayuela María Auxiliadora , Rama‐Iñiguez Sara , Bolás‐Fernández Francisco
Published: June 2006

Leishmaniasis is a zoonotic disease caused by the species of the genus Leishmania, flagellated protozoa that multiply inside mammalian macrophages and are transmitted by the bite of the sandfly. The disease is widespread and due to the lack of fully effective treatment and vaccination the search for new drugs and immune targets is needed. Proteomics seems to be a suitable strategy because the annotated sequenced genome of L. major is available. Here, we present a high‐resolution proteome for L. infantum promastigotes comprising of around 700 spots. Western blot with rabbit hyperimmune serum raised against L. infantum promastiogote extracts and further analysis by MALDI‐TOF and MALDI‐TOF/TOF MS allowed the identification of various relevant functional antigenic proteins. Major antigenic proteins were identified as propionil carboxilasa, ATPase beta subunit, transketolase, proteasome subunit, succinyl‐diaminopimelate desuccinylase, a probable tubulin alpha chain, the full‐size heat shock protein 70, and several proteins of unknown function. In addition, one enzyme from the ergosterol biosynthesis pathway (adrenodoxin reductase) and the structural paraflagellar rod protein 3 (PAR3) were found among non‐antigenic proteins. This study corroborates the usefulness of proteomics in identifying new proteins with crucial biological functions in Leishmania parasites.
Reactivity trends and stereospecificity in nucleophilic substitution reactions
Authors: Uggerud Einar
Published: June 2006

To obtain the full overview of the mechanistic landscape of nucleophilic substitution reactions is a demanding pursuit. There are still many unexplored regions, and humility and carefulness should be exercised before drawing the final map. This review commentary emphasizes some recent findings of relevance to these questions. A critical account is given about commonly used concepts and practices for interpretation of reactivity trends. It is questioned whether the SN2/SN1 paradigm is fully appropriate for understanding the factors which govern the outcome of substitution reactions. Copyright © 2006 John Wiley & Sons, Ltd.