bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Different Drying Processes on the Material Properties of Bacterial Cellulose Membranes
Authors: Clasen C. , Sultanova B. , Wilhelms T. , Heisig P. , Kulicke W.‐M.
Published: January 2007

Summary: Membranes of bacterial cellulose produced by Gluconacetobacter xylinus show a high water and gas permeability that can be altered by different drying techniques. It could be shown that freeze‐drying reduces the swellability of the polymer membranes by a factor of 5 while evaporation drying causes a reduction by a factor of 50. The strong decrease of swellability for an evaporation dried membrane could be correlated with a reduction of the absolute number of polymer strands that form the network structure of the membrane, determined with oscillatory shear rheological experiments. The removal of network meshes by a complete aggregation of polymer strands could be confirmed by IR‐spectroscopy with an increased degree of intramolecular hydrogen bonding of cellulose strands. In contrast to this, the freeze‐drying process shows a slight increase of the number of network meshes due to partial aggregation of free polymer strands. Freeze‐dried membranes show a gas permeability two orders of magnitude higher then evaporation dried membranes. The absolute permeability strongly depends on the bacterial strain used for the polymer membrane synthesis and varies by up to 1.5 orders of magnitude for the same drying process. The Young's modulus of the polymer membranes varies with the bacterial strain used, but does not show the same trends as the permeability. Finally, a comparison of the characterized properties shows that only one of the tested strains shows the capability to synthesize membranes that meets the requirements for an application as a wet wound dressing.
Studies on Non‐natural Deoxyammonium Cellulose
Authors: Heinze Thomas , Koschella Andreas , Brackhagen Meinolf , Engelhardt Jürgen , Nachtkamp Klaus
Published: January 2007

Summary: Ammonium group containing cellulose derivatives are prepared from homogeneously synthesized cellulose p‐toluenesulfonic acid esters (tosyl cellulose) by conversion with sodium azide and subsequent reduction of the azido moiety applying NaBH4/CoBr2/2,2′‐bipyridine as reagent. Regarding the tosylation, cellulose samples of different degree of polymerization and hemicellulose content possess a different reactivity. The deoxyamino cellulose is water soluble in the protonated state. Elemental analysis, FTIR‐ and NMR spectroscopy were carried out to analyze the degree of substitution and functionalization pattern. It was also studied to synthesize deoxyazido celluloses without isolation of the tosyl cellulose. However, a predominant formation of deoxychloro moieties occurs.
Mechanical Properties of Regenerated Cellulose Fibres for Composites
Authors: Adusumali Ramesh‐Babu , Reifferscheid Moritz , Weber Hedda , Roeder Thomas , Sixta Herbert , Gindl Wolfgang
Published: January 2007

Summary: A broad variety of regenerated cellulose fibres was subjected to single fibre tensile tests in order to determine the modulus of elasticity, tensile strength, and failure strain. The results were compared to glass fibres and flax fibres, which are considered the most important technical and natural fibres, respectively. With regard to their modulus of elasticity and tensile strength, regenerated cellulose fibres showed clearly lower values than glass fibres, even when their low density was taken into account. The average modulus of elasticity and tensile strength of regenerated cellulose fibres was also lower than the values measured for flax fibres, but when variability was considered, both fibres performed similarly. In terms of interfacial shear strength with polypropylene, lyocell fibres performed significantly less well than sized glass fibre and ramie fibre. The most important difference between regenerated cellulose fibres and both glass and flax fibres is their high failure strain and thus high work to fracture. The high work to fracture of regenerated cellulose fibres makes them particularly useful for composite applications where high fracture toughness is required.
Nanocellulose Polymer Composites as Innovative Pool for (Bio)Material Development
Authors: Kramer Friederike , Klemm Dieter , Schumann Dieter , Heßler Nadine , Wesarg Falko , Fried Wolfgang , Stadermann Dietmar
Published: January 2007

Summary: Using a “never‐dried” procedure (according to Figure 4) shaped bacterial nanocellulose (BC, 1% cellulose, 99% water) has been modified by the formation of BC‐polymer composites. For this purpose, acrylate and methacrylate monomers and methacrylate crosslinkers were photopolymerized inside an ethanol‐swollen nanofiber network. Using the ethanol as solvent and as confirmed by model reactions the synthetic polymer (SP) part of the composites is constructed of crosslinked polymers (number of repeating units in the range of 500). As part of ongoing work on the development of (bio)materials from the innovative pool of BC composites these investigations are recently directed towards the creation of collagen‐like materials. Thus, for these purposes, mainly water absorption capacity, strength, and elasticity have to be controlled, whilst still retaining essential features of BC like shape, nanofiber network, pore system, and proved biocompatibility. Using acrylic acid, 2‐ethylhexyl acrylate, 2‐hydroxyethyl methacrylate, N‐vinyl pyrrolidone as acrylate monomers and triethylene glycol dimethacrylate and 1,4‐butandiol dimethacrylate as crosslinkers of different concentrations either a filling of the pores or a coating of the fibers in the BC nanocomposites could be achieved. The small cellulose content of the composites significantly increases the water absorption value and the strength of the material as well as the ability of re‐swelling in the case of fiber coated composites. Sample 12 is an optimized BC‐SP composite regarding important properties of hyaline cartilage like Young's modulus in the range of 5–20 MPa using the well‐known Simplex‐method.
Functionalized Cellulose Based Microcomposites
Authors: Kolbe Axel , Meister Frank
Published: January 2007

Summary: A technique has been developed that allows the production of cellulosic micro composites by immobilizing super‐ground functionalised materials in the cellulose matrix. For this purpose, the well‐established ALCERU® process has been a subject of technological modification. Depending on the degree of filling, several types of composites are accessible. At lower concentrations, the fibres maintain their textile‐physical parameters and may be used in applications, where a textile appearance is required. The increasing concentration of the functional additives influences increasingly the overall properties of the composite and leads to composites with special functions such as water retention, electric conductivity, and specific absorption ability for organics or heat storage functions. In addition, loads exceeding the cellulose portion are useful as green shapes for ceramics.
Copper Corrosion: Comparison between Naturally Aged Papers and Artificially Aged Model Papers
Authors: Henniges Ute , Bürger Ulrike , Banik Gerhard , Rosenau Thomas , Potthast Antje
Published: January 2007

Summary: Copper corrosion on paper works of art is commonly explained by copper ion‐catalysed cellulose oxidation, usually reflected by discoloration of pigment and surrounding paper as well as by loss of mechanical strength. In this study, model paper and historic paper samples, both containing copper pigments, were compared using fluorescence labelling of carbonyl groups and subsequent GPC analysis. The historic paper samples did not show any typical sign of copper pigment induced discoloration, but high brittleness. In artificially copper‐corroded paper samples the distribution of carbonyl groups in combination with the molecular weight distribution of cellulose clearly indicated the occurrence of oxidative processes. In contrast, only insignificant oxidative damage was detected in the case of the paper fragments from an original work of art, a codex from the 15th century. Here, mostly degradation by hydrolytic action was revealed. There was no introduction of carbonyl groups into the bulk section of the molecular weight distribution, and the gain in new carbonyl groups corresponded to the number of reducing end groups newly generated by hydrolysis.
Phase Behavior of Amphiphilic Molecules in the Presence of One Solvent: A Dissipative Particle Dynamics Study
Authors: Huang Ching‐I , Hsueh Hsiao‐Yang , Lan Yi‐Kang , Lin Yu‐Chih
Published: January 2007

We simulate the phase behavior of amphiphilic molecules in the presence of one solvent by DPD. In general, DPD has successfully captured most of the effects of composition of amphiphilic molecules, solvent selectivity, and solvent amount, on the phase transition behavior obtained by both SCMF calculations and experiments. When a neutral good solvent is added, the solutions undergo a lyotropic transition analogous to the thermotropic transition in the melts. Furthermore, the order‐disorder transition results obtained via DPD are in good agreement with theoretical predictions by including the fluctuation effects, as well as with experiments. In the selective solvents, various transitions from the “normal” phases (i.e., the minority blocks form the minor domains) to even the “inverted” phases (formed by the majority blocks) have been observed by varying solvent selectivity and solvent amount. Since the packing order of the spheres is greatly affected by the finite size of the simulation box, it becomes difficult to examine the most stable packing array of spheres via DPD as has been predicted by SCMF theory. However, DPD reveals a possible spherical order of A15, which has been ignored in current SCMF work but observed in some amphiphilic molecule systems.

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Models and methods of decision making in fuzzy environment and their applications to power engineering problems
Authors: Canha L. , Ekel P. , Queiroz J. , Schuffner Neto F.
Published: January 2007

Results of research into the use of fuzzy sets for handling various forms of uncertainty in optimization problems are presented. Two types of situations which need the application of a multicriteria approach are classified. According to this, two classes of models (〈X, M〉 and 〈X, R〉 models) are considered with utilizing the Bellman–Zadeh approach to decision making in a fuzzy environment and techniques for modelling of fuzzy preference relations for their analysis. The application of the Bellman–Zadeh approach for solving 〈X, M〉 problems conforms to the principle of guaranteed result and provides constructive lines in obtaining harmonious solutions on the basis of analysing associated maxmin problems. Analysis of 〈X, R〉 models is considered as part of a general approach to solving problems with fuzzy coefficients. Three techniques for processing of fuzzy preferences relations are considered. The first technique is associated with building and analysing a membership function of a subset of non‐dominated alternatives considering all criteria simultaneously. The second technique is of a lexicographic character and consists in step‐by‐step consideration of criteria. The third technique is based on aggregating membership functions of subsets of non‐dominated alternatives for each criterion. The results of the paper are universally applicable and are already being used to solve power engineering problems. It is illustrated by considering problems of multicriteria power and energy shortage allocation, multicriteria power system operation, and substation planning with considering criteria of quantitative as well as of qualitative character. Copyright © 2007 John Wiley & Sons, Ltd.
Analysis of block matrix preconditioners for elliptic optimal control problems
Authors: Mathew T. P. , Sarkis M. , Schaerer C. E.
Published: January 2007

In this paper, we describe and analyse several block matrix iterative algorithms for solving a saddle point linear system arising from the discretization of a linear‐quadratic elliptic control problem with Neumann boundary conditions. To ensure that the problem is well posed, a regularization term with a parameter α is included. The first algorithm reduces the saddle point system to a symmetric positive definite Schur complement system for the control variable and employs conjugate gradient (CG) acceleration, however, double iteration is required (except in special cases). A preconditioner yielding a rate of convergence independent of the mesh size h is described for Ω ⊂ R2 or R3, and a preconditioner independent of h and α when Ω ⊂ R2. Next, two algorithms avoiding double iteration are described using an augmented Lagrangian formulation. One of these algorithms solves the augmented saddle point system employing MINRES acceleration, while the other solves a symmetric positive definite reformulation of the augmented saddle point system employing CG acceleration. For both algorithms, a symmetric positive definite preconditioner is described yielding a rate of convergence independent of h. In addition to the above algorithms, two heuristic algorithms are described, one a projected CG algorithm, and the other an indefinite block matrix preconditioner employing GMRES acceleration. Rigorous convergence results, however, are not known for the heuristic algorithms. Copyright © 2007 John Wiley & Sons, Ltd.
Decreased EXT expression and intracellular accumulation of heparan sulphate proteoglycan in osteochondromas and peripheral chondrosarcomas
Authors: Hameetman L , David G , Yavas A , White SJ , Taminiau AHM , Cleton‐Jansen A‐M , Hogendoorn PCW , Bovée JVMG
Published: January 2007

Mutational inactivation of EXT1 or EXT2 is the cause of hereditary multiple osteochondromas. These genes function in heparan sulphate proteoglycan (HSPG) biosynthesis in the Golgi apparatus. Loss of heterozygosity of the EXT1 locus at 8q24 is frequently found in solitary osteochondromas, whereas somatic mutations are rarely found. We investigated the expression of EXT1 and EXT2 (quantitative RT‐PCR) and of different HSPGs (immunohistochemistry) in solitary and hereditary osteochondromas and in cases with malignant progression to secondary peripheral chondrosarcoma, in relation to possible mutations and promoter methylation. The mutation status of patients with multiple osteochondromas correlated with decreased EXT1 or EXT2 expression found in their resected tumours. We could not show somatic point mutations or promoter hypermethylation in 17 solitary tumours; however, EXT1 expression was decreased in 15 cases, whereas EXT2 was not. Intracellular accumulation of syndecan‐2 and heparan sulphate‐bearing isoforms of CD44 (CD44v3) was found in most tumours, which concentrated in the Golgi apparatus as shown by confocal microscopy. This contrasted with the extracellular expression found in normal growth plates. In conclusion, mutational inactivation of either EXT1 or EXT2 leads to loss of mRNA expression of the corresponding gene. We hypothesize that loss of EXT expression disrupts the function of the EXT1/2 complex in HSPG biosynthesis, resulting in the intracellular accumulation of HSPG core proteins that we found in these tumours. Copyright © 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Changes in cancer worry associated with participation in ovarian cancer screening
Authors: Andersen M. Robyn , Drescher Charles W. , Zheng Yingye , Bowen Deborah J. , Wilson Susan , Young Alicia , McIntosh Martin , Mahony Barry S. , Lowe Kimberly A. , Urban Nicole
Published: January 2007

While ovarian cancer is rare and screening is not recommended for most women, it is being studied as a way to reduce ovarian cancer mortality. As effective strategies for screening emerge it will be important to understand the quality of life (QOL) effects of participation in ovarian cancer screening. In this study, we examined the effects of participation in an ovarian cancer screening program on worry about cancer risk and QOL. A randomized controlled clinical trial (n = 592) was conducted. Women without a family history suggestive of a BRCA1/2 mutation were randomly assigned to screening and risk counseling, separately and in combination. Results were compared to women randomized to usual care alone. Levels of cancer worry fell for all study groups and QOL was unaffected; no statistically significant differences were found between groups. Increased levels of worry about ovarian cancer at 2‐year follow‐up were found among participants in screening receiving abnormal test results. For those who receive abnormal results, screening may have long‐term effects and increase worry about cancer risk. Further research will be required to examine the possibility that screening reduces worry when women receive only normal, presumably reassuring, results. Copyright © 2007 John Wiley & Sons, Ltd.
Strengthening GLP compliance through internal audits
Authors: Li Henry , Pifat Dominique , Klein Gerald , Petteway Steve
Published: January 2007

The Quality Assurance (QA) strategy for assessing Good Laboratory Practice (GLP) compliance at different testing facilities varies from focusing on study data verification to taking a quality system approach. As a best practice and to ensure overall compliance with GLP regulations, the Quality Assurance Unit (QAU) should perform three types of internal audits: study‐specific, process‐based, and system inspection. These internal audits serve as a tool to ascertain whether a GLP compliance program is functioning correctly. Information gathered from these audits can also be used to provide assistance during the evolution of a new GLP compliance program. As the GLP compliance program matures, internal audits can be a useful mechanism to help maintain compliance and promote continued improvement. Copyright © 2006 John Wiley & Sons, Ltd.
GLP SOPs for equipment calibration and maintenance part 3: process mapping for SOP development
Authors: Colligon Irina , Rosa Michelle
Published: January 2007

Ask almost anyone who has been involved in writing Standard Operating Procedures (SOPs) about how they learned to do it and chances are the answer will be that they just sat down and wrote their ideas, maybe using a standard format. Although process flows and flow charts have been an integral part of the computer world for as long as most care to remember, it has only been in the past decade or so that the concepts of process design and process flows have started to enter the realm of SOP development in the pharmaceutical industry. In this installment of the series, we will describe one process design approach to developing SOPs for a laboratory. Copyright © 2006 John Wiley & Sons, Ltd.
A High‐Throughput Methodology for Screening Solution‐Based Chelating Agents for Efficient Palladium Removal
Authors: Flahive Erik , Ewanicki Brigitte , Yu Shu , Higginson Paul D. , Sach Neal W. , Morao Iñaki
Published: January 2007

A simple and efficient screening methodology for scavenger reagent identification was carried out to overcome the high levels of residual palladium present in the Axitinib process. The purification strategy relied on crystallization of the desired product from the crude reaction mixture leaving the residual palladium in the mother liquor by using Pd‐chelating agents. Theoretical models based on naïve Bayesian classifier were also performed to support the screening team. Using the best model, a virtual screening of commercially available compounds was conducted and new theoretical hits were generated. Some of these theoretical ligands were then tested experimentally, confirming the validity of our model.
Similarity‐Based Descriptors (SIBAR) as Tool for QSAR Studies on P‐Glycoprotein Inhibitors: Influence of the Reference Set
Authors: Zdrazil Barbara , Kaiser Dominik , Kopp Stephan , Chiba Peter , Ecker Gerhard F.
Published: January 2007

Polyspecific proteins, such as the cytochrome P450 enzyme family, the hERG potassium channel and the ABC‐type multidrug efflux pumps ABCB1, ABCC1 and ABCG2 are increasingly recognised as playing a major role in bioavailability and toxicity of drugs. Although considerable efforts have been undertaken to establish in silico tools for predicting drug–protein interactions, especially in the field of ABC pumps, general applicable models are still rare. We recently showed that similarity‐based descriptors are a versatile tool for prediction of ABCB1 (P‐glycoprotein, P‐gp) inhibitory activity. These descriptors are based on the calculation of similarity values between the compounds of the training set to a group of reference set compounds. The similarity values are subsequently used as independent variables in QSAR analyses. Within this paper, we address the influence of the reference set on the predictive ability of QSAR models for a set of 412 inhibitors of the multidrug efflux pump ABCB1. Four different reference sets were designed comprising highly diverse, drug‐like compounds (A), a subset of the training set compounds (B), a set of manually selected ABCB1 inhibitors (C) and low molecular weight chemicals (D). Our results indicate that a combination of high diversity and an interaction of the reference compounds with the biological target is beneficial for yielding good models. The reference dataset tailored to the specific problem (the biological target) scored best in predicting the biological activity of compounds from an external test set.
New possible ionic structures in Wittig reaction: Analysis of stability and rotation barriers by semiempirical PM3 method
Authors: Mracec Maria , Pascariu Aurelia , Berger Stefan , Mracec Mircea
Published: January 2007

For the Wittig reaction between butylidentriphenylphosphorane and benzaldehyde studied previously using NMR spectroscopy, three ionic intermediates have been proposed in order to explain the “stereochemical drift” (different ratio in oxaphosphetane stereoisomers compared with the ratio of the final Z/E olefins). In this paper, the PM3 semiempirical MO method was applied on the proposed ionic intermediates. Two of the ionic intermediates could lead to a shift of the reaction towards the final products, olefins and phosphine oxide, while the third intermediate could be implicated in a retro‐Wittig reaction. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
The interpretation of exposure effect estimates in chronic air pollution studies
Authors: Haneuse S. , Wakefield J. , Sheppard L.
Published: January 2007

In this article we consider the interpretation of regression parameters used to represent ‘chronic’ or ‘long‐term’ air pollution exposure effects. Although scientific interest typically lies in understanding such effects at the level of the individual, studies have generally employed a semi‐ecological design; outcomes and confounder information are collected on individuals while exposure is only available at the aggregate‐or group‐level. A precise interpretation of results from a semi‐ecological design must take into account the aggregated nature, both spatial and temporal, of the exposure measure. The most common analysis approach for assessing chronic exposure effects has been within the Cox proportional hazards model framework; specific analyses are tailored to accommodate the shortcomings of the available exposure information. We revisit the underlying assumptions of the Cox model and discuss the implications of two common aspects of chronic effects studies: time‐dependent exposures and time‐varying effects. Focusing on the consequences of temporal aggregation of exposure, we show that an estimate obtained from a time‐aggregated semi‐ecological design can correspond to very different underlying time‐varying exposure and risk scenarios. Further, distinguishing which of these is correct is not possible from the semi‐ecological data alone. Our goal is to highlight some statistical issues faced by existing studies of chronic air pollution effects, and aid in the development and planning of future studies. Copyright © 2007 John Wiley & Sons, Ltd.
Zur probabilistischen Bemessung von Stahlrahmen
Authors: Křivý Vít , Marek Pavel
Published: January 2007

Der Beitrag befaßt sich mit den Möglichkeiten der Zuverlässigkeitsbeurteilung von Stahlrahmen unter Anwendung der SBRA (Simulation‐Based Reliability Assessment)‐Methode, die in [1] beschrieben ist. Die ständige Verbesserung der Computertechnik macht es möglich, das Potential der SBRA‐Methode nicht nur für die Analyse einfacher Tragwerke und ihrer Komponenten, sondern auch für die Beurteilung von komplizierten, statisch unbestimmten Konstruktionen, wie z. B. Stahlrahmen, anzuwenden.

In diesem Zusammenhang wird ein möglicher Übergang von der traditionellen und in den derzeitigen Normen angewendeten Beurteilung der Knickstabilität von Stahlrahmen (die auf der Bestimmung von Knicklängen und Knickzahlen beruht) zu der auf der SBRA‐Methode und der Analyse nach Theorie II. Ordnung gegründete Festigkeitsauffassung über Stabilität, vorgestellt.
Methodik zur Beurteilung des Brandverhaltens von Metallkonstruktionen
Authors: Skowroński Wojciech
Published: January 2007

Im vorliegenden Beitrag wird eine Methodik zur Brandbemessung von Metallkonstruktionen unter Temperatureinwirkung vorgeschlagen, die zeitabhängige Effekte berücksichtigt und gleichzeitig ermöglicht, einen Einfluß der Erwärmungsgeschwindigkeit auf den Tragfähigkeitverlust der Konstruktion zu berücksichtigen. Eine Aufklärung über zeitabhängige Effekte ist unabdingbar, wenn eine Bemessung unter Berücksichtigung von Brandtemperaturanstiegskurven notwendig ist. Solche Differenzierungen wurden international im Eurocode 1 festgelegt, aber sie werden wegen fehlender Methodik zum Tragfähigkeitsnachweis bisher nicht bei der Bemessung von Metallkonstruktionen im Brandfall angewandt. Die Brandbemessung müßte auf einer begründeten Wahl einer konkreten Temperatur‐Zeit‐Kurve, die mehr oder weniger intensiven Brand beschreibt, und auf konsequent durchgeführten Berechnungen zum Tragfähigkeitsnachweis beruhen, die es ermöglichen den Einfluß der Erwärmungsgeschwindigkeit auf das Verhalten der Konstruktion zu berücksichtigen.
Interference analysis and capacity for forward link 3G CDMA network with adaptive antennas
Authors: Kavak Adnan , Karakoç Mustafa , Torlak Murat , Ozdemir Caner
Published: January 2007

In code division multiple access (CDMA) systems, the capacity of forward link (FL) communication to mobile receivers is limited primarily by co‐channel interference (CCI). Adaptive antenna arrays (AAAs) that use antenna arrays along with advanced signal processing at the base station (BS) have been proposed to mitigate this limitation. For a 3G CDMA cellular network, where each BS equipped with an AAA serves mixture of voice and data users within its coverage, we study FL capacity and investigate the effects of different factors (array topology, multipath angle spread, data rate, and beamforming algorithm) on this capacity under Rayleigh fading channel. By modeling the instantaneous signal‐to‐interference power ratio received at the mobile, we derive the system outage equation that considers blocking of either desired voice or data user. Simulation results show that for the same element spacing and number of antenna elements per cell, the uniform circular array (UCA) topology results in larger capacity than the sectorized uniform linear array (ULA) topology does, and that a larger angle spread or data user rate reduces FL capacity. Copyright © 2007 John Wiley & Sons, Ltd.
A new authentication protocol based on pointer forwarding for mobile communications
Authors: Lee Cheng‐Chi , Hwang Min‐Shiang , Liao I‐En
Published: January 2007

A frequently moving mobile user in GSM must re‐register at the HLR frequently, and, therefore, the signaling traffic is overhead and HLR database update cost raised. In this paper, the authors propose a new authentication protocol, based on pointer forwarding to reduce the HLR update cost and traffic load for the MS authentication protocol. The proposed protocol for GSM can achieve some objectives described in Introduction. Compared with other authentication protocols, our protocol is efficient. Copyright © 2007 John Wiley & Sons, Ltd.
Habitat preferences of an endangered insect species, Cepero's ground‐hopper (Tetrix ceperoi)
Authors: Gröning Julia , Krause Sascha , Hochkirch Axel
Published: January 2007

Preventing the global decline in biodiversity is a major task for conservation biologists. Although habitat loss has been identified as a key factor driving extinction processes, our knowledge on the habitat requirements of many endangered species, particularly invertebrates, is still sparse. We present a feasible method to study the microhabitat preferences of insect species. In Central Europe, the endangered Cepero's ground‐hopper, Tetrix ceperoi, is believed to have its only remaining natural habitats in dune slacks of the Wadden Sea Islands. Our results suggest that this species performs an active habitat choice of damp, bare patches with high temperatures. While ponds and fens in dune slacks provide large areas of damp bare ground and algal mats, grasslands, degraded dune slacks and the transitional zone between salt marsh and dunes are less suited as habitats. The major threat for T. ceperoi is found in the succession of its pioneer habitats due to the reduced natural dynamics. In industrialized countries, pioneer habitats and species are threatened substantially by coastal protection and floodplain regulation. This is only compensated in part by anthropogenic creation of secondary habitats, such as different kinds of pits or coal heaps. Nevertheless, there is a strong need for restoration of dynamic habitats by floodplain revitalization and dune slack restoration.
Simulating phenological characteristics of two dominant grass species in a semi‐arid steppe ecosystem
Authors: Yuan Wenping , Zhou Guangsheng , Wang Yuhui , Han Xi , Wang Yingshun
Published: January 2007

Vegetation phenology has a strong effect on terrestrial carbon cycles, local weather, and global radiation partitioning between sensible and latent heat fluxes. Based on phenological data that were collected from a typical steppe ecosystem at Xilingol Grazing and Meteorological Station from 1985 to 2003, we studied the phenological characteristics of Leymus chinensis and Stipa krylovii. We found that the dates for budburst of L. chinensis and S. krylovii were delayed with increasing temperature during winter and spring seasons; these results differed from existing research in which earlier spring events were attributed to the changes in increasing air temperature in winter and spring. The results also suggested that water availability was an important controlling factor for phenology in addition to temperature in grassland plants. The classical cumulative temperature model simulated the phenology well in wet years, but not in the beginning of growing season in all years from 1985 to 2003. The disparity between the simulation and the observation appeared to be related to soil water. Based on our research findings, a water‐heat‐based phenological model was developed for simulating the beginning of growing season for these two grass species. The simulated results of the new model showed a significant correlation with the observation of beginning date of the growing season, and both mean values of the absolute error were less than 6 days.
Lack of field‐based recruitment to carbohydrate food in the Korean yellowjacket, Vespula koreensis
Authors: Kim Kil Won , Noh Suegene , Choe Jae Chun
Published: January 2007

We investigated field‐based recruitment via visual, chemical and acoustic cues provided by conspecific wasps on carbohydrate feeders in Vespulakoreensis. A wild colony nest was excavated and artificially installed in a field site. Naïve foragers were individually marked and trained to an experimental feeder. We conducted three separate experiments in which foragers were presented with feeder dishes with different cue intensities. For the first, a different number of decoys were posed as if feeding (visual cue). In the second, dishes had been previously visited by different numbers of individuals, thus presenting different concentrations of a possible food site marking substance (chemical cue). In the third, each dish was placed in front of a covered flask with a different number of nestmates inside (acoustic cue combined with body‐odor cue). We observed no social facilitation or social inhibition due to any of the experimental cues. Previous studies in Vespula species have shown a variety of foraging strategies ranging from local enhancement to local inhibition. Field‐based recruitment mechanisms in yellowjackets may have evolved independently in different lineages.
Hard‐Surface Cleaning Using Lipases: Enzyme–Surfactant Interactions and Washing Tests
Authors: Jurado Encarnación , Bravo Vicente , Luzón Germán , Fernández‐Serrano Mercedes , García‐Román Miguel , Altmajer‐Vaz Deisi , Vicaria José María
Published: January 2007

A commercial lipase (E.C. 3.1.1.3) from Thermomyces lanuginosus was studied in order to assess its interaction with commercial nonionic (Findet® 1214N/16, Findet 1214N/23 and Glucopon® 650) and anionic (linear alkylbenzene sulphonate; LAS) surfactants, as well as the cleaning action exerted by the enzyme on hard surfaces. Nonionic surfactants seem to prevent or delay enzyme penetration at the interface, thereby decreasing lipase activity. Notably, no inhibitory effect of the anionic surfactant LAS on lipase action was found, higher conversions being achieved after 20 min of enzymatic hydrolysis in the presence of this surfactant than in its absence. A device for testing detersive performance, the so‐called bath–substrate–flow, was used in washing experiments with the lipase at different temperatures with or without surfactant. Employing two different oily stains (tributyrin and triolein), it was found that the lipase by itself increases detergency significantly, preventing the subsequent redeposition of the removed dirt. Expressions relating detersive efficiency to lipase concentration and temperature were obtained using “Statistical Design of Experiments” methodology.
Syntheses of Ring C Oxysterols: Inhibitors of Sterol Biosynthesis
Authors: Parish Edward J. , Luo Chi , Webb Thomas , Gorden John D.
Published: January 2007

Oxygenated derivates of cholesterol and lanosterol, known as oxysterols, have consistently displayed significant activity as inhibitors of 3‐hydroxy‐3‐methylglutaryl (HMG) CoA reductase, a key regulatory enzyme in sterol biosynthesis. We have developed the chemical syntheses of ring C oxysterols for evaluation as inhibitors of sterol biosynthesis. A key intermediate in the chemical synthesis was 3β‐benzoyloxy‐9α, 1α‐epoxy‐5α‐cholest‐7‐ene (1), whose structure was confirmed by X‐ray crystallographic analysis and is presented herein.
Birds and marine mammals in southwestern Foxe Basin, Nunavut, Canada
Authors: Gaston Anthony J. , Smith Stephen A. , Saunders Robert , Storm G. Ilya , Whitney Jane A.
Published: January 2007

The southwestern part of Foxe Basin is a little known region of the Canadian Arctic, being difficult to access during the summer because of heavy and unpredictable ice conditions. Surveys of birds and marine mammals in the area were carried out by lightweight expeditions in the summers of 1994 and 1995, using sea-kayaks, as well as a Peterhead boat from the nearest community, at Repulse Bay. The area supports important populations of narwhal, bowhead whales and walrus, as well as significant concentrations of shorebirds, common eiders, black guillemots, and perhaps one third of the world's Thayer's gulls. New information was obtained on the status and abundance of these species and novel observations were made on the feeding ecology and breeding phenology of the gulls.
Legacies of the Jackson-Harmsworth expedition, 1894–1897
Authors: Savitt Ronald , Lüdecke Cornelia
Published: January 2007

Frederick George Jackson, the leader of the Jackson-Harmsworth Expedition of 1894–1897, accomplished a great deal during his exploration of Franz Josef Land [Zemlya Frantsa-Iosifa] although his achievements have never been fully acknowledged. Jackson's expedition itself has often been eclipsed by his famous meeting in 1896 with Fridtjof Nansen, absent for 3 years in the Arctic and it has been unfairly coloured by the view that Jackson was no more than an adventurer and sportsman. The research reported in this article evaluates Jackson's plan and management activities. The study developed a set of factors to evaluate his performance arising from a variety of expeditions contemporary with Jackson's. His strong personality and limited personnel managerial experience limited the full extent of what he might have achieved. Yet, Jackson developed a strong exploration model that was based on comprehensive planning, a significant concern for the health and welfare of his companions, the willingness to innovate in a number of activities including sledging, and a commitment to scientific discovery. Although the expedition did not find a route to the North Pole, Jackson confirmed that Franz Josef Land was an archipelago and he gave credence to the consumption of fresh meat as a means of preventing scurvy. One of Jackson's legacies to subsequent explorers was the use of ponies for haulage. He was unable to appreciate the weaknesses in their use and his influence on subsequent Antarctic expeditions often led to undesirable results. But, overall, Jackson was an innovator in a conservative exploration community.
Political mobilisation of northern indigenous peoples in Russia
Authors: Semenova Tamara
Published: January 2007

The analysis of international and national cooperation interprets relations between states, international organisations and indigenous peoples as currently being constructed in terms of political practices. Through practical work in their organisations (IPOs), indigenous peoples are building up a joint agenda to further their social and economic interests. This process is accompanied by a transformation of the agenda of sovereign states and subordinate government bodies as well as by the establishment of partnerships with indigenous peoples through their legally recognised organisations that have become new political actors. New methods are emerging in which these practices can evolve in the most efficient way: the recognition of IPOs as equal partners in the decision-making process; the allocation of resources to facilitate their participation; the incorporation of traditional knowledge; the accommodation of indigenous priorities; joint initiatives; and other collective actions. The intergovernmental forum of the Arctic Council may serve as a positive model in which both governments and indigenous peoples collaborate. IPOs fully participate in the regional decision-making process, and through building up a new collective identity, reach out to high-level international organisations and events such as the World Summit on Sustainable Development and the UN Permanent Forum on Indigenous Issues. In Russia, at the national level, the process has been less successful than elsewhere. This formation of collective identity is connected to two processes: one is a search for new opportunities of interaction with the state in the legal and governmental sphere: the other comprises regional cooperation and local interpretation of sustainable development. This is an INDIPO project paper (Tennberg 2006).
Obituary
Authors: Van Autenboer Tony
Published: January 2007

Baron Gaston de Gerlache de Gomery died on 13 July 2006 at the age of 86 (Fig. 1). On 11 January 1958, the 60 year old flag of Belgica flew once more in Antarctica when a short ceremony marked the construction of a geophysical observatory in Dronning Maud Land. This Belgian contribution to the International Geophysical Year (IGY) of 1957–1958, as well as the subsequent Belgian Antarctic programmes were made possible thanks to the interest, initiative and unrelenting effort of Baron Gaston de Gerlache de Gomery. Like his famous father Adrien de Gerlache, at the end of the previous century, he managed to convince politicians and scientists that the world was not confined by the borders of Belgium.
Discovery of the wreck of the Soviet steamer Chelyuskin on the bed of the Chukchi Sea
Authors: Barr William
Published: January 2007

In 1933, the steamer Chelyuskin sailed from Murmansk, east bound to attempt a transit of the Northern Sea Route to the Pacific, in order to demonstrate that such a transit could be achieved in one season. The vessel became beset in heavy ice in the Chukchi Sea, and after drifting with the ice for over two months, was crushed and sank on 13 February 1934. Apart from one fatality, her entire complement of 104 people was able to establish a camp on the sea ice. The Soviet government organised an impressive aerial evacuation, under which all were rescued. Following several unsuccessful attempts, the wreck was located on the bed of the Chukchi Sea by a Russian expedition, Chelyuskin-70, in mid-September 2006. Two small components of the ship's superstructure were recovered by divers and were sent to the ship's builders, Burmeister and Wein of Copenhagen, for identification.
Terra Nova: the ship's bell, figure-head, standard compass and binnacle
Authors: Tarver Michael C.
Published: January 2007

This note reports on the three relics of Terra Nova, the vessel of R. F. Scott's last expedition, that still exist. These are the ship's bell, which is in the Scott Polar Research Institute, Cambridge, the figurehead held by the National Museum of Wales in Cardiff and the standard compass and binnacle in the Royal Navy's School of Navigation, Portsmouth.
A further note on the Belgica project
Authors: Loy Walter , van Autenboer Tony
Published: January 2007

Further progress is reported concerning the preservation of Belgica, currently a wreck in Norwegian waters. A plan is currently being developed for furthering this aim.
Experimental manipulation of cognitive control processes causes an increase in communication disturbances in healthy volunteers
Authors: KERNS JOHN G.
Published: January 2007

Background. Although communication disturbances (CD) have been associated with poor cognitive control, it is unclear whether they are associated specifically with poor cognitive control or with poor cognition in general. The current research examined whether (a) two specific components of cognitive control, working memory and interference resolution, were associated with CD, and (b) associations between CD and cognitive control could be accounted for by generalized poor cognitive performance.

Method. In this study, as healthy volunteers spoke, the level of cognitive demands was experimentally increased, thereby simulating cognitive deficits (i.e. a reduction in the degree to which certain types of cognitive processes could be used for speech). Hence, this research examined whether simulated cognitive deficits would cause an increase in CD. Participants also completed separate cognitive tasks that assessed working memory, interference resolution and general cognitive ability.

Results. An increase in working memory demands caused an increase in CD. Moreover, working memory demands interacted with interference resolution demands, with the greatest amount of CD caused by both high working memory and high interference resolution demands. By contrast, increasing another cognitive demand, sustained attention, did not increase CD. Furthermore, performance on separate working memory and interference resolution tasks interacted to predict CD on the experimental speech task. However, performance on a psychometrically matched cognitive task did not predict CD.

Conclusion. Overall, the current study provides evidence that working memory and interference resolution may be specifically associated with CD and that manipulations of these cognitive control processes can cause an increase in CD.
Participant distress in psychiatric research: a systematic review
Authors: JORM ANTHONY F. , KELLY CLAIRE M. , MORGAN AMY J.
Published: January 2007

Background. There has been ethical concern that participants in psychiatric research will become distressed and their mental state might worsen.

Method. A systematic search was carried out for studies that examined distress following participation in research that involved the assessment of psychiatric state or associated risk factors. There were 46 relevant studies.

Results. A minority of participants become distressed immediately after participation, with distress more likely in studies of traumatic experiences. There is limited evidence on longer-term effects, but what there is suggests no adverse impact. Positive reactions to participation show little association with distress and these are more common than negative reactions. Very few studies of distress in research have used control groups to establish causal associations. However, what evidence there is suggests no causal role, including for research on suicidality. Researchers in this area have made a range of suggestions about ethical practice.

Conclusions. A minority of participants in psychiatric research become distressed, but there is no evidence of longer-term harm. Nevertheless, researchers need to take account of ethical concerns in designing studies. Future research in the area needs to be carried out with stronger designs involving control groups.
Enhanced emotion-induced amnesia in borderline personality disorder
Authors: HURLEMANN RENÉ , HAWELLEK BARBARA , MAIER WOLFGANG , DOLAN RAYMOND J.
Published: January 2007

Background. Current biological concepts of borderline personality disorder (BPD) emphasize the interference of emotional hyperarousal and cognitive functions. A prototypical example is episodic memory. Pre-clinical investigations of emotion–episodic memory interactions have shown specific retrograde and anterograde episodic memory changes in response to emotional stimuli. These changes are amygdala dependent and vary as a function of emotional arousal and valence.

Method. To determine whether there is amygdala hyper-responsiveness to emotional stimuli as the underlying pathological substrate of cognitive dysfunction in BPD, 16 unmedicated female patients with BPD were tested on the behavioural indices of emotion-induced amnesia and hypermnesia established in 16 healthy controls.

Results. BPD patients displayed enhanced retrograde and anterograde amnesia in response to presentation of negative stimuli, while positive stimuli elicited no episodic memory-modulating effects.

Conclusion. These findings suggest that an amygdala hyper-responsiveness to negative stimuli may serve as a crucial aetiological contributor to emotion-induced cognitive dysfunction in BPD.
Jugglers, Fakirs, and Jaduwallahs: Indian Magicians and the British Stage
Authors: Dadswell Sarah
Published: January 2007

This article offers an historical analysis of the emergence and development of Asian magicians on the British stage. Sarah Dadswell charts the trajectory of this phenomenon from the arrival of the first recorded Indian magicians in the UK in the early nineteenth century to the internationally renowned figure of P. C. Sorcar in the mid-twentieth century. In doing so, she illustrates the dialogue that took place between East and West, recording the ways in which both sides recognized and adopted the other's modes of performance and marketing strategies to suit their needs and satisfy public demand. Sarah Dadswell is Research Fellow to the AHRC-funded project ‘British Asian Theatre’ at the University of Exeter. This article forms part of the project's investigation into the history and development of modes of performance by Asian theatre practitioners in the UK.