bluuebunny/crossref_metadata_2025 huggingface dataset:
The Froude number stick, an evaluation
Authors: Seip Knut Lehre
Published: January 2004

This paper examines whether horizontal free surface flow patterns can reveal bulk river flow characteristics, such as the Froude number. To do this, the Froude number was measured between 0.2 and 1.2 by visually observing the flow patterns around a wooden stick, the so‐called ‘Froude stick’ described in the literature. The stick has been hypothesized to estimate the Froude number at the transition between subcritical and supercritical flow based on free‐surface flow patterns. The study objective was twofold: to obtain (i) a measure of the Froude number independent of estimates of water velocity and stream depth; and (ii) a tool that would allow the field biologist to assess hydrodynamic properties of streams. The results show that the stick measures only water velocity. As water velocity increases from about 0.2 m s−1, to 0.45 m s−1, an obtuse V‐shaped flow pattern around the stick obtains a right‐angle that is easy to detect by the naked eye, and wavelets upstream of the stick are more than 1 cm wide. With increasing water velocities the V‐shaped flow pattern becomes pointed, and at velocities a little larger than 1.0 m s−1 the upstream wavelets disappear. Copyright © 2004 John Wiley & Sons, Ltd.
Reconstruction of the characteristics of a natural alluvial river–floodplain system and hydromorphological changes following human modifications: the Danube River (1812–1991)
Authors: Hohensinner S. , Habersack H. , Jungwirth M. , Zauner G.
Published: January 2004

Based on detailed historical surveys from 1812, the natural riverine landscape of a 10.25‐km‐long reach of the Danube River in the Austrian Machland region prior to channelization is analysed. Anthropogenically induced changes of fluvial dynamics, hydrological connectivity and aquatic habitat composition are discussed, comparing the situations following channelization (1925) and flow regulation (1991). In 1812 the alluvial river–floodplain system of the Danube River comprised a highly complex channel network, numerous gravel bars and extensive islands, with the main channel and side arms (eupotamon) representing about 97% of the entire water surface at low flow. The floodplain was characterized by relatively flat terrain and numerous natural trenches (former active channels) connected to the main channel. These hydromorphological conditions led to marked expansion/contraction of the water surface area at water level fluctuations below bankfull (‘flow pulse’). The high degree of hydrological connectivity enabled intensive exchange processes and favoured migrations of aquatic organisms between the river and floodplain habitats over a period of approximately 90 days per year. Overall in 1812, 57% of the active zone (active channels and floodplain) was inundated at bankfull water level.

Channelization and construction of hydropower plants resulted in a truncated fluvial system. Consequently, eupotamal water bodies decreased by 65%, and gravel/sand bars and vegetated islands decreased by 94% and 97%, respectively, whereas the area of the various backwaters doubled. In 1991 the former ‘flow pulse’ was halved due to artificial levees and embankments, greatly diminishing hydrological connectivity and decoupling large areas of the floodplain from the main channel. Active overflow, formerly playing an important role, is now replaced by backwater flooding and seepage inflow in isolated water bodies. Copyright © 2003 John Wiley & Sons, Ltd.
Habitat loss as the main cause of the slow recovery of fish faunas of regulated large rivers in Europe: the transversal floodplain gradient
Authors: Aarts Bram G. W. , Van Den Brink Fred W. B. , Nienhuis Piet H.
Published: January 2004

In large European rivers the chemical water quality has improved markedly in recent decades, yet the recovery of the fish fauna is not proceeding accordingly. Important causes are the loss of habitats in the main river channels and their floodplains, and the diminished hydrological connectivity between them.

In this study we investigate how river regulation has affected fish community structure in floodplain waterbodies of the rivers Rhône (France), Danube (Austria), Rhine and Meuse (The Netherlands). A typology of natural and man‐made aquatic habitats was constructed based on geomorphology, inundation frequency and ecological connectivity, along the transversal river–floodplain gradient, i.e. perpendicular to the main stream of the river. Fish species were classified in ecological guilds based on their flow preference, reproduction ecology and diet, and their status on national red lists was used to analyse the present state of the guilds and habitats.

Ecological fish guilds appear to be good indicators of ecological integrity and functioning of river–floodplain systems. A transversal successional gradient in fish community structure that bears some resemblance to the gradient found in natural rivers can still be discerned in heavily regulated rivers. It resembles the longitudinal river gradient; even some predictions of the River Continuum Concept are applicable. Overall, richness and diversity of species and ecological guilds decrease with decreasing hydrological connectivity of floodplain waterbodies.

Anthropogenic disturbances have affected fish species unevenly: guilds of specialized species that are highly adapted to specifically riverine conditions have declined far more than generalist species. Fish habitats in the main and secondary channels have suffered most from regulation and contain the highest percentage of threatened species. Rheophilic fishes have become rare because their lotic reproductive habitats are severely degraded, fragmented, absent or unreachable. Limnophilic fishes have become rare too, mainly as a result of eutrophication. Eurytopic fishes have become dominant everywhere. Copyright © 2003 John Wiley & Sons, Ltd.
Characteristics and temporal variability of large woody debris trapped in a reservoir on the River Rhone (Rhone): implications for river basin management
Authors: Moulin B. , Piegay H.
Published: January 2004

Woody debris is a structural element of river systems, which provides habitats for aquatic communities but may enhance flooding frequency and damage infrastructure. An abundant scientific literature highlights the role of the wood, particularly in the fields of ecology and geomorphology. In order to find a balance between woody debris preservation and reintroduction for ecological purposes, and the need for channel clearing for risk management, more research is now needed to understand woody debris delivery residence time and transport dynamics in regulated rivers.

This work uses reservoirs, which trap woody debris, to determine its geographical origin and temporal variability in relation to the flow regime. This approach is illustrated by data collected on the Genissiat dam on the upper Rhône river (France), which traps all the woody debris even during high floods.

The results show that the wood input increases with flood frequency but also depends on the position of the flood event in the hydrological series. The wood load is significantly high and removed from the reservoir when the flood recurrence attains one in 1.5 years. Qualitative description of the wood extracted from the reservoir indicates that 83% of the pieces, whatever the size, have a natural origin (broken, cut by beaver) and 17% has been cut by humans. The large pieces of wood (diameter >12.5 cm) more frequently have a human origin (40%).

Large pieces with roots are infrequent (10%) underlining the low contribution of bank erosion. Most of the pieces are strongly smoothed, without any branches, roots and bark confirming the effect of physical breakage of high energy rivers. Amongst 503 samples, 45% have a riparian origin (Populus, Fraxinus, Alnus). Copyright © 2003 John Wiley & Sons, Ltd.
Systems/operational research and sustainable development: towards a new agenda
Authors: Midgley Gerald , Reynolds Martin
Published: January 2004

At the 2002 International Sustainable Development Research Conference in Manchester, a great number of the 53 papers presented addressed exciting methodological developments associated with action research. Many of these initiatives can be linked with the rich tradition of operational research (OR). OR and environmental planning for sustainable development share three traditions: first, both have wide boundaries in terms of clientele, range of methodological approaches used and attention to multiple (and often conflicting) values; second, both traditions have an interest in fostering interdisciplinarity; third, both OR and environmental planning are concerned with the implementation, as well as the design, of planning strategies. Given these shared traditions, we recently engaged in a systemic intervention project to explore the possibilities of improved collaboration between OR practitioners and environmental planners. In a literature review and interviews with stakeholders, three generic issues were found to recur: complexity and uncertainty (regarding the unpredictability of natural and social phenomena); multiple and often conflicting values (of those involved in environmental planning) and political effects (on those not involved in planning processes, including non‐human nature). This paper reveals a pattern of how these generic issues are perceived in the public, business and voluntary sectors, and explains how, through a series of workshops and a mini‐conference, three interrelated agendas for future action took shape. Copyright © 2003 John Wiley & Sons, Ltd and ERP Environment.
Experiences with sustainability indicators and stakeholder participation: a case study relating to a ‘Blue Plan’ project in Malta
Authors: Bell Simon , Morse Stephen
Published: January 2004

The practical application of systemic sustainability analysis (SSA; Bell and Morse, 1999) as applied in a project instigated and managed by ‘Blue Plan’, one of the regional activity centres of the Mediterranean Action Plan, is set out and explained in this paper. The context in which SSA was applied and adapted to SPSA (systemic and prospective sustainability analysis) is described in the Mediterranean, primarily in Malta.

The SSA process is summarized, its extension and linkage to the prospective approach is described and the comments of stakeholders in the context are added. Some preliminary outcomes are suggested. The particular focus of the paper is on the lessons learned from doing SSA/SPSA within a classic blueprint project framework. It is not assumed that SSA/SPSA is ‘finished’ or ‘definitive’. Rather, we suggest that it is a developing and changing approach that practitioners can adapt and change to meet the specific needs of the circumstances that confront them. Copyright © 2004 John Wiley & Sons, Ltd and ERP Environment.
What we buy, what we throw away and how we use our voice. Sustainable household waste management in the UK
Authors: Barr Stewart
Published: January 2004

Sustainable waste management is a core issue facing local and national governments. It is widely acknowledged that although producers of goods and materials have a role to play in reducing waste, the general public, in the way that we consume and utilize products, have a key role in delivering sustainable waste management. This paper supports this assertion with data from a study of waste management attitudes and reported behaviours in southwest England. The paper presents a conceptual framework for examining attitudes and behaviours towards waste management, incorporating environmental values, situational factors and psychological variables. Using this framework, the paper demonstrates the range of influences acting on attitudes and actions towards sustainable waste management practices, focusing especially on recycling behaviour. The paper argues that the framework could provide a useful tool for examining the variety of factors influencing a range of public actions relevant to sustainable development. Copyright © 2004 John Wiley & Sons, Ltd and ERP Environment.
The effects of potential reform of the CAP on greenhouse gas emissions from Irish agriculture: an extensification scenario
Authors: Behan Jasmina , McQuinn Kieran
Published: January 2004

Unlike most developed countries, agriculture is the greatest single source of greenhouse gases in Ireland and accounts for approximately one‐third of the national emissions. In this paper, the future emissions of greenhouse gases from Irish agriculture are projected using an economic model of the Irish agricultural sector. Coefficients from the Intergovernmental Panel on Climate Change (IPCC) are used to convert the raw agricultural data from the economic model to emission levels. These projections are generated under two different scenarios: the first is a baseline result, which holds the present agricultural policy environment – the EU Common Agricultural Policy (CAP) – constant for the projection period. The second result is the projection of emissions under a particular policy reform scenario. The effect of this scenario on emissions is measured relative to the baseline result. Copyright © 2004 John Wiley & Sons, Ltd and ERP Environment.
TXRF heavy metal analysis after immobilization as PAN complexes
Authors: Kallithrakas‐Kontos N.
Published: January 2004

1‐(‐2‐Pyridylazo)‐2‐naphthol (PAN) forms stable complexes with many metals of environmental interest. A few micrograms of PAN were immobilized in a Nafion membrane, the membrane was put on quartz reflectors and the reflectors were immersed in standard aqueous solutions containing nickel, copper, manganese and vanadium salts at very low concentrations (µg l−1 level). The reflectors were left in the solutions for many hours at constant temperature. When the equilibration stage was finished, they were cleaned with ultra‐pure water and left to dry. Analysis of the samples was performed by total reflection x‐ray fluorescence (TXRF) spectrometry. A few µg l−1 of the above metals were determined. The effects of equilibration time and temperature on the measured x‐ray yields were examined. Copyright © 2003 John Wiley & Sons, Ltd.
Chemical determination of coloured zoned minerals in ‘natural stones’ by EDS/WDS electron microprobe: an example from dumortierite quartzites
Authors: Borghi Alessandro , Cossio Roberto , Fiora Laura , Olmi Filippo , Vaggelli Gloria
Published: January 2004

Dumortierite is a rather uncommon borosilicate [(Al1−x□x) Al2Al4Si3BO18−3x(OH)3x] occurring in rare and precious commercial ‘natural stones’ which hold an economic interest related to their properties and colour. These stones are petrographically known as quartzites, whose blue colour is given by variable amounts of dumortierite. A petrographic and mineral chemistry study of blue dumortierite quartzites from Brazil, Mozambique and Madagascar mines, in order to elucidate the relationships between colour and chemical variations, was performed.

Two different dumortierite generations were detected. The first occurs as millimetric porphyroblasts from the Mozambique sample and shows a marked zoning for Al, Si, Ti and Sb. The second is characterised by submillimetric prismatic crystals, which are lesser zoned. For both generations, a good correlation between Ti concentration zoning and pleochroism variations was observed. In particular, the comparison between polarised light images of single dumortierite crystals and the Ti distribution X‐ray maps evidences the good correlation existing between Ti content and blue colour variations. Moreover, dumortierite from Mozambique quartzites displays an unusual occurrence of Sb, with concentrations ranging up to 5 wt.% (expressed as Sb2O3). Copyright © 2003 John Wiley & Sons, Ltd.
Identification of overglaze and underglaze cobalt decoration of ceramics from Valencia (Spain) by portable EDXRF spectrometry
Authors: Roldán C. , Coll J. , Ferrero J. L. , Juanes D.
Published: January 2004

The purpose of this work is the application of non‐destructive analysis to differentiate underglaze and overglaze techniques used in the decoration of glazed ceramics from Valencia (Spain). This study was carried out by portable EDXRF spectrometry using an X‐ray tube and a thermoelectrically cooled semiconductor detector. From the EDXRF spectra we have identified the main elements present in the tin‐opacified lead glaze and in the cobalt pigments. The identification of the underglaze and overglaze decoration is based on the different ratios between the fluorescence line of the main component of the glaze (Pb‐Lα line) and the fluorescence lines of the main components of the pigment (Co‐Kα, Mn‐Kα, Ni‐Kα, … lines) when the incident angle of the X‐ray beam varies. If the position of the detector is fixed, these ratios (Pb/Co, Pb/Mn, Pb/Ni, …) increase with the angle for underglaze decoration, and decrease for overglaze decoration. Copyright © 2003 John Wiley & Sons, Ltd.
Application of the TXRF method to the elemental analysis of cerebrospinal fluid in amyotrophic lateral sclerosis
Authors: Ostachowicz B. , Boruchowska M. , Lankosz M. , Tomik B. , Szczudlik A. , Adamek D.
Published: January 2004

The total reflection x‐ray fluorescence technique was applied to the determination of the elemental composition of cerebrospinal fluid (CSF) in the neurodegenerative disease amyotrophic lateral sclerosis (ALS). Samples of the CSF from two groups of patients, ALS and control, were analysed. Two methods of sample preparation were tested in order to improve the detection limits of the analysed elements. The elements Cl, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Rb and Rb were found and determined. Differences in the concentrations of Zn and Cl were found between the ALS and the control group. Copyright © 2004 John Wiley & Sons, Ltd.
Determination of the elemental composition of aortic valve cusps by EDXRF
Authors: Wróbel A. , Goncerz G. , Kunz J. , Podolec P. , Rokita E.
Published: January 2004

The aim of these studies was to develop a procedure for the determination of elemental concentrations in aortic valve cusps based on XRF measurements and to evaluate whether the XRF method may be useful in mineralization studies. The investigations were conducted on aortic valves collected at autopsy from 12 donors. Concentrations of 14 elements (Mg, Al, Si, P, S, Cl, K, Ca, Mn, Fe, Ni, Cu, Zn and Sr) were determined. The cusp areal density determination was based on Compton scattering measurement. Calcium concentration was considered as an indicator of mineralization development. The results revealed differences in the elemental compositions of the cusps constituting one aortic valve for donors older than ∼40 years, whereas no differences were observed in younger donors. There was a correlation between advancement of the mineralization process in the aortic valves, assessed by the Ca concentration, and donors' age. Acceleration of the process was observed for subjects older than 40 years. It may be concluded that homografts should be collected from donors younger than 40 years. Copyright © 2004 John Wiley & Sons, Ltd.
Synchrotron microprobe determination of the elemental distribution in human teeth of the Neolithic period
Authors: Carvalho M. L. , Marques J. P. , Marques A. F. , Casaca C.
Published: January 2004

The purpose of the present work was to investigate whether the distribution of trace elements in human teeth of the Neolithic period in Portugal can reflect environmental conditions, dietary habits and uptake of some elements from the surrounding soil. An x‐ray fluorescence set‐up with microprobe capabilities, installed at the LURE synchrotron (France), was used for elemental analysis of teeth. The resolution of the synchrotron microprobe was 100 µm and the energy of the incident beam was 18 keV. The synchrotron microprobe concentration profiles for V, Mn, Fe, Cu, Zn, Sr and Pb in different regions of the tooth are discussed and correlated with the results obtained by cranio‐facial studies. The Mn and Fe concentrations were much higher in Neolithic teeth than in those of present humans. This may suggest uptake of both elements from the soil. Low concentration levels of Sr were found, which can be correlated with dietary habits. Moreover, the Pb concentration was very low in all the teeth analysed, in agreement with the low pollution levels of this element in this population. All samples were analysed without any chemical preparation. Copyright © 2004 John Wiley & Sons, Ltd.
Proton‐induced x‐ray emission using 68 MeV Protons
Authors: Denker A. , Opitz‐Coutureau J.
Published: January 2004

The x‐ray production cross‐sections for the K lines of heavy elements is large enough at 68 MeV proton energy to detect heavy elements via the K in addition to their L x‐rays. The large proton penetration range and the fact that the absorption coefficients for the x‐ray K lines are much smaller than for the L lines result in an analytical depth of several millimeters. The intensity ratio between the stimulated x‐ray L and K lines yields information about the physical composition (e.g. layered structure, layer sequence, hidden structure elements) of the samples supplementary to their chemical composition. Also, based on the now detectable K lines, spectra with mixtures of heavy elements are easier to evaluate, as the K lines will overlap less than the L lines. The experimental set‐up and several examples of measurements on archaeological and art historical objects are presented. Copyright © 2004 John Wiley & Sons, Ltd.
High energy resolution XRMF spectrometer using polycapillary x‐ray optics and PSPC
Authors: Ding Xunliang , Liu Zhiguo , Yan Yiming , Pan Qiuli
Published: January 2004

A new spectrometer based on a plane crystal wavelength dispersive method using a position‐sensitive proportional counter (PSPC) in conjunction with an x‐ray microbeam formed by a monolithic polycapillary x‐ray focusing lens has been developed. The new spectrometer could be used for x‐ray microfluorescence (XRMF) analysis with high sensitivity, high spatial resolution and energy resolution simultaneously. The minimum spot size of the x‐ray beam focused by the lens is 50 µm for Cu Kα. An energy resolution of 4.4 eV is obtained for Ti Kα by means of the spectrometer. The detectable energy range of the spectrometer in one run without a scanning procedure is more than 800 eV. Some results of sample analysis with the spectrometer are presented. Copyright © 2004 John Wiley & Sons, Ltd.
Assessing scattering effects in annular radioisotope excited XRF
Authors: Padilla Alvarez Román , Van Espen Pierre , Abrahantes Quintana Arian
Published: January 2004

Rayleigh and Compton scattered radiation is used in various correction procedures for quantitative x‐ray fluorescence analysis. However, the information derived from the measured scatter peaks is altered by several phenomena in the case of annular radioisotope excitation, causing the calculated results to deviate, often significantly, from the expected values. In this work, we assessed the main sources of inaccuracy when using measured scatter intensities. Monte Carlo simulation was used to trace the radiation transport in the geometric arrangement source–sample–collimator–detector and to estimate the contribution of different effects to the measured Rayleigh and Compton scatter peaks. The information obtained in this way was used to extend the IAEA–QXAS standardless fundamental parameter approach to the case of annular radioisotope excitation and to formulate a method to correct for spurious fluorescent peaks appearing in blank measurements. Copyright © 2004 John Wiley & Sons, Ltd.
Isolation and characterization of Candida albicans homologue of RAP1, a repressor and activator protein gene in Saccharomyces cerevisiae.
Authors: Uemura Hiroshi , Watanabe‐Yoshida Miyuki , Ishii Nobuya , Shinzato Tomoko , Haw Robin , Aoki Yuko
Published: January 2004

To study the function of RAP1, a Candida albicans gene (CaRAP1) that shows sequence similarity to RAP1 of Saccharomyces cerevisiae was isolated by colony hybridization. DNA sequencing predicted an open reading frame of 429 amino acids with an overall identity of 24% to the ScRap1p. The DNA binding domain (DBD) was highly conserved, and EMSA using a GST–CaRap1p fusion protein confirmed its binding ability to the RPG‐box of S. cerevisiae ENO1. In contrast, the N‐terminus was less conserved and a moderate homology was observed in the BRCT domain. Interestingly, CaRap1p did not contain the C‐terminal activation/repression region of ScRap1p. Its DDBJ/EMBL/GenBank Accession No. is AB036055. Copyright © 2003 John Wiley & Sons, Ltd.
Identification of an UDP‐Glc:glycoprotein glucosyltransferase in the yeast Yarrowia lipolytica
Authors: Babour A. , Beckerich J.‐M. , Gaillardin C.
Published: January 2004

The UDP‐Glc:glycoprotein glucosyltransferase (UGT) is a soluble protein of the endoplasmic reticulum (ER) that plays a determining part in the mechanism by which unfolded, partially folded or misfolded glycoproteins are retained into the ER. We have identified an UGT in the yeast Yarrowia lipolytica. This protein, of a predicted molecular weight of 165.7 kDa, is encoded by a 5054 bp coding sequence containing a 643 bp intron at position 682–1323. The N‐terminal part of the protein displays a signal sequence whereas its C‐terminal part carries an ER retrieval signal HDEL. An interruption of the gene that removes the 1075 last nucleotides of its sequence did not lead to any evident phenotype except for a slight increased sensitivity to tunicamycin. YlUGT1 mRNA levels respond to tunicamycin treatment by an induction factor of 2–4, which indicates that the gene product participates in the quality control mechanism in this yeast. Finally, an immunofluorescence study of the protein localization, shows that the protein distribution is different from that of previously studied ER resident proteins. This could indicate that UGT distribution in the secretory pathway is not confined to the ER. Copyright © 2003 John Wiley & Sons, Ltd.
Alanine : glyoxylate aminotransferase of Saccharomyces cerevisiae–encoding gene AGX1 and metabolic significance
Authors: Schlösser Thomas , Gätgens Cornelia , Weber Ulrike , Stahmann K.‐Peter
Published: January 2004

Alanine : glyoxylate aminotransferase is one of three different enzymes used for glycine synthesis in Saccharomyces cerevisiae. The open reading frame YFL030w (named AGX1 in the following), encoding this enzyme, was identified by comparing enzyme specific activities in knockout strains. While 100% activity was detectable in the parental strain, 2% was found in a YFL030w::kanMX4 strain. The ORF found at that locus was suspected to encode alanine : glyoxylate aminotransferase because its predicted amino acid sequence showed 23% identity to the human homologue. Since the YFL030w::kanMX4 strain showed no glycine auxtrophic phenotype, AGX1 was replaced by KanMX4 in a Δ GLY1Δ SHM1Δ SHM2 background. These background mutations, which cause inactivation of threonine aldolase, mitochondrial and cytosolic serine hydroxymethyltransferase, respectively, lead to a conditional glycine auxotrophy. This means that growth is not possible on glucose but on ethanol as the sole carbon source. Additional disruption of AGX1 revealed a complete glycine auxotrophy. Complementation was observed by transformation with a plasmid‐encoded AGX1. Copyright © 2003 John Wiley & Sons, Ltd.
The high general stress resistance of the Saccharomyces cerevisiae fil1 adenylate cyclase mutant (Cyr1Lys1682) is only partially dependent on trehalose, Hsp104 and overexpression of Msn2/4‐regulated genes
Authors: Versele Matthias , Thevelein Johan M. , Van Dijck Patrick
Published: January 2004

The initiation of fermentation in the yeast Saccharomyces cerevisiae is associated with a rapid drop in general stress resistance. Previously we identified a mutant which is deficient in fermentation‐induced loss of stress resistance (fil1), as a partially inactivating mutant in adenylate cyclase. We have now investigated possible causes of its high stress resistance. Deletion of the TPS1 gene, encoding the first enzyme in the biosynthesis of trehalose, or the heat shock protein gene HSP104 only resulted in a minor effect on heat stress resistance compared with deletion of these genes in a wild‐type background. A strain with a deletion of both genes still showed a higher stress resistance in the fil1 background compared to the corresponding wild‐type background. Deletion of the transcription factor genes MSN2 and MSN4, which are required for the expression of STRE‐regulated genes, resulted in a dramatic drop in heat resistance in the wild‐type background but had much less effect in the fil1 mutant. The fil1 msn2Δmsn4Δ strain remained more heat‐resistant than a wild‐type strain. A strain in which all four genes, TPS1, HSP104, MSN2 and MSN4, are deleted was very sensitive to heat stress and also to oxidative and salt stress. Presence of the fil1 mutation in such a strain, however, still clearly enhanced heat, oxidative and salt stress resistance. These results indicate that, in addition to trehalose, Hsp104 and the Msn2/4‐controlled genes, other factors exist in S. cerevisiae that can, significantly and independently of the known factors, enhance general stress resistance. The mutants described in this work provide a tool to identify these novel components. Copyright © 2003 John Wiley & Sons, Ltd.
Ein ungewöhnlicher ambivalenter Zinn(II)‐oxo‐Cluster
Authors: Niemeyer Mark
Published: January 2004

Die Umsetzung des Kupferaryls CuDmp (Dmp = 2, 6‐Mes2C6H3; Mes = 2, 4, 6‐Me3C6H2) mit dem Stannandiyl Sn{1, 2‐(tBuCH2N)2C6H4} führt nach langsamer Hydrolyse in Gegenwart von Lithium‐tert‐butanolat mit geringer Ausbeute zu dem Zinn(II)‐oxo‐Cluster {(Et2O)(LiOtBu)(SnO)(CuDmp)}2 (5). Die Festkörperstruktur der farblosen Verbindung zeigt ein zentrales Li2Sn2O2(OtBu)2‐Fragment mit Heterocubanstruktur. Zusätzlich werden die Li‐Akzeptor‐ und O(Sn)‐Donoratome zur Koordination von je einem Molekül Diethylether und Kupferaryl CuDmp benutzt.
A New Octadecanuclear Copper(II)‐Lanthanide(III) Cluster Complex: Synthesis and Structural Characterization of [Cu12Nd6(OH)24(betaine)16(NO3)3(H2O)10](NO3)[PF6]14·5H2O
Authors: Yang Yang‐Yi , Huang Zhong‐Qi , He Feng , Chen Xiao‐Ming , Ng Seik Weng
Published: January 2004

The new octadecanuclear Cu‐Ln complex, [Cu12Nd6(OH)24(betaine)16(NO3)3(H2O)10](NO3)[PF6]14·5H2O, was synthesized, which crystallizes in triclinic P1¯ space group, a = 18.649(6)Å, b = 20.363(7)Å, c = 19.865(7)Å, α = 116.61(2)°, β = 91.99(2)°, γ = 117.93(2)°, V = 5666(3)Å3. Its crystal structure features a [Cu12Nd6(OH)24(betaine)16(NO3)3(H2O)10]15+ core of pseudocubic Oh symmetry, with the six Nd ions positioned at the vertices of a regular octahedron and the twelve Cu ions located at the midpoints of the twelve octahedral edges. The Cu‐Nd metal framework may be viewed as a cuboctahedron, which is interconnected by twenty‐four μ3‐OH bridges that are each linked to one Nd ion and two Cu ions. In the centre of metal polyhedron, there is an encapsulated NO3— anion that exhibits a multi‐ coordinating mode.
Synthesis and Structure of a Three‐dimensional Organically Templated Zinc Ethylenediphosphonate, [NH3(CH2)2NH3][Zn3{O3P(CH2)2}4]
Authors: Natarajan Srinivasan
Published: January 2004

A hydrothermal reaction of a mixture of ZnO, HCl, ethylenediphosphonic acid, ethylenediamine, acetic acid in a water, THF mixture gave rise to a new three‐dimensional zinc ethylenediphosphonate, [NH3(CH2)2NH3][Zn3{O3P(CH2)2}4], I. The structure, determined by single crystal X‐ray diffraction, (monoclinic, space group = C2/c, a = 16.9948(14), b = 6.7383(6), c = 16.8886(14)Å, β = 1113.568(1)°, V = 1772.7(3)Å3, Z = 4, R1 = 0.0227, wR2 = 0.0601), consists of a network of strictly alternating ZnO4 and PO3C tetrahedral units linked through their vertices forming the three‐dimensional structure. The amine molecules occupy the middle of the 8‐membered channels and interact with the framework through the hydrogen bonds. Unlike other zinc diphosphonates, I appear to have close similarity to zinc phosphate structures reported in the literature. To our knowledge, this is the first three‐dimensional zinc diphosphonate prepared in the presence of an organic amine molecule.
Magnetic Investigations and 151Eu Mössbauer Spectroscopy of MYbSi4N7 with M = Sr, Ba, Eu
Authors: Höppe Henning A. , Trill Henning , Kotzyba Gunter , Mosel Bernd D. , Pöttgen Rainer , Schnick Wolfgang
Published: January 2004

The isotypic nitridosilicates MYb[Si4N7] (M = Sr, Ba, Eu) were obtained by the reaction of the respective metals with Si(NH)2 in a radiofrequency furnace below 1600 °C. On the basis of powder diffraction data of MYb[Si4N7] Rietveld refinements of the lattice constants were performed; these confirmed the previously published single‐crystal data. The compounds contain a condensed network of corner‐sharing [N(SiN3)4] units. The central nitrogen thus exhibits ammonium character. Magnetic susceptibility measurements of MYb[Si4N7] (M = Sr, Ba, Eu) show paramagnetic behavior with experimental magnetic moments of 3.03(2), (Sr), 2.73(2) (Ba), and 9.17(2) (Eu) μB per formula unit. In EuYbSi4N7 the europium and ytterbium atoms are in stable divalent and trivalent states, respectively. According to the non‐magnetic character of the alkaline earth cations, ytterbium has to be in an intermediate valence state YbIII‐x in the strontium and barium compound. Consequently, either a partial exchange N3—/O2— resulting in compositions MYbIII‐x[Si4N7—xOx] or an introduction of anion defects according to MYbIII‐x[Si4N7—x/3□x/3] has to be assumed. The phase width 0 ≤ x ≤ 0.4 was estimated according to the magnetic measurements. 151Eu Mössbauer spectra of EuYb[Si4N7] at 78 K show a single signal at an isomer shift of δ = —12.83(3) mm s—1 subject to quadrupole splitting of ΔEQ = 5.7(8) mm s—1, compatible with purely divalent europium.
Neue heterometallische Organoderivate von Haupt‐ und Nebengruppenelementen mit dem 2‐(Dimethylaminomethyl)ferrocenyl(1‐)‐Liganden FcN(1‐) und der N‐[2‐N′, N′‐(Dimethyl‐aminoethyl)‐N‐methyl‐aminoethyl]ferrocenyl(1‐)‐Gruppierung FcN, N(1‐)
Authors: Jacob Klaus
Published: January 2004

Neuartige — vorzugsweise seit 1998 beschriebene — heterometallische Organoderivate von Haupt‐ und Nebengruppenelementen mit dem 2‐(Dimethylaminomethyl)ferrocenyl(1‐)‐Liganden FcN(1‐) und dem N‐[2‐N′, N′‐(Dimethylaminoethyl)‐N‐methyl‐aminoethyl]ferrocenyl(1‐)‐ Rest FcN(1‐) als Organogruppen werden zusammenfassend vorgestellt. Es wird ein Überblick verwendeter Synthesemethoden und vorliegender Molekülstrukturen gegeben.
Zur Kenntnis der inversen Perowskite M3TO (M = Ca, Sr, Yb; T = Si, Ge, Sn, Pb)
Authors: Velden A. , Jansen M.
Published: January 2004

Ca3SiO und sieben weitere inverse Perowskite M3TO (M = Ca, Sr, Yb; T = Si, Ge, Sn, Pb) wurden durch die Reaktion 6 M + TO2 + T = 2 M3TO bzw. 3 M + TO = M3TO für Yb3PbO in verschlossenen Reineisentiegeln unter Argon bei Temperaturen von 1123—1173 K dargestellt. Die Kristallstrukturen aller Verbindungen wurden mit Röntgenpulvermethoden bestimmt und verfeinert. Ca3SiO, Ca3GeO, Sr3SiO, Sr3GeO sowie Yb3SiO und Yb3GeO sind orthorhombische Perowskite (anti‐GdFeO3‐Typ, Raumgruppe Pbnm, Nr. 62, Z = 4). Sie sind aus schwach verzerrten, eckenverknüpften OM6‐Oktaedern aufgebaut, die bezüglich ihrer Lagen in der idealen inversen Perowskit‐Struktur gekippt sind. Der Wirkungsradius von T4— variiert signifikant mit der Art der M2+, weshalb diese Verbindungen außerhalb des Geltungsbereichs des “hard‐sphere” Modells liegen und der Goldschmidt'sche Toleranzfaktor als strukturchemisches Kriterium nicht mehr greift. Die ideal‐kubischen Verbindungen Yb3SnO und Yb3PbO wurden in der Raumgruppe Pm3¯m verfeinert (anti‐SrTiO3‐Typ, Z = 1).
Caesium Heptaiodo‐Dititanate(III), CsTi2I7
Authors: Jongen Liesbet , Meyer Gerd
Published: January 2004

Caesium heptaiodo‐dititanate(III), CsTi2I7, is obtained from CsI, Ti and TiI4 at 250 °C in a sealed tantalum ampoule as dark red single crystals. The crystal structure (trigonal, R‐3, a = 1706.6(3), c = 2088.3(5) pm, Z = 12, R1 = 0.0619) contains [TiI4] tetrahedra sharing common vertices (with Ti—I—Ti angles of 180°) to isolated ditetrahedra [Ti2I7]—. It may also be described as a cubic closest packing of alternating CsI3 and I4 layers between which neighbouring tetrahedra are occupied in a way that [Ti2I7]— ditetrahedra are achieved.

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New Phases in the Lithiumnitridovanadate System — The Solid Solution Li7‐2xMgx[VN4] with 0 ≤ x ≤ 1
Authors: Niewa Rainer , Zherebtsov Dmitry A.
Published: January 2004

Solid solution phases Li7‐2xMgx[VN4] (0 < x ≤ 1) with varying Mg‐content are obtained as yellow microcrystalline powders from heat treatment of mixtures of VN, Li3N and Mg3N2 or from mixtures of Li7[VN4] and Mg3N2 at 1370 K in N2 atmosphere at ambient pressure. At substitution parameter values of x > 0.5 a subsequent distortion from the ideal cubic unit cell to an orthorhombic unit cell is observed. The crystal structure of Li7‐2xMgx[VN4] with x ≈ 1 was refined from neutron and X‐ray powder diffraction data (space group Pbca, No. 61, a = 963.03(3) pm, b = 958.44(3) pm, c = 951.93(2) pm, neutron pattern 14° — 156° 2θ, step non‐linear ≈ 0.0782° 2θ, No. of measured points 1816, Rp = 0.089, Rwp = 0.115, RBragg = 0.155, RF = 0.114; X‐ray pattern 10° — 98° 2θ, step 0.005° 2θ, No. of measured points 17600, Rp = 0.028, Rwp = 0.045, RBragg = 0.113, RF = 0.133, structure variables: 45). The crystal structure resembles a Li2O type superstructure with the atomic arrangement of β‐Li7[VN4] and with two crystallographic Li‐sites each substituted by Mg with statistical occupation factors of 0.5. Chemical analyses prove the composition and XAS spectroscopy at the V K‐edge support the +5 oxidation state assignment for vanadium. XAS data also support the tetrahedral coordination of vanadium by N as indicated by the structure refinements.
Synthesis, Spectral, Valence‐Bond Parameters, and Single Crystal X‐ray Structural Studies on [Ni(dnpdtc)(PPh3)(NCS)] and [Ni(dnpdtc)(PPh3)(CN)]
Authors: Prakasam B. Arul , Ramalingam K. , Bocelli G. , Olla R.
Published: January 2004

Two new nickel complexes withplanar surrounding of Ni [Ni(dnpdtc)(PPh3)(NCS)] (1) and [Ni(dnpdtc)(PPh3)(CN)] (2) (dnpdtc=N, N‐dipropyldithiocarbamate) were prepared from the parent dithiocarbamate and were characterized by elemental analysis, electronic, IR and NMR spectra. The structures of both the complexes were determined by single crystal X‐ray crystallography. Thioureide stretching vibrations occur at 1528 cm‐1 and 1521 cm‐1 for 1 and 2 respectively. Large 31P chemical shifts were observed for the two compounds. A significant asymmetry in Ni—S bond distances was observed in compound 1 [2.1700(16) and 2.2251(17)Å] whereas in compound 2 the bond distances were almost similar [2.2100(14) and 2.2122(13)Å]. A marginal difference was observed with respect to the thioureide bond distances [1.340(6)Å for 1 and 1.312(5)Å for 2]. The observation clearly supports the less effective trans influence of SCN— over PPh3. However, PPh3 and CN— show almost similar trans influence.
Single Crystal Growth and Crystal Structure of Mercurous Diarsenate(V), (Hg2)2(As2O7)
Authors: Weil Matthias
Published: January 2004

Polycrystalline mercurous diarsenate(V), (Hg2)2(As2O7), was prepared by a redox‐reaction between stoichiometric amounts of HgO and As2O3. Canary yellow single crystals were obtained by subsequent chemical transport reactions using HgCl2 as transport agent [550 → 500 °C, 5 d, sealed and evacuated silica ampoules]. The crystal structure (orthorhombic, Pnma, Z = 4, a = 9.9803(8), b = 12.2039(10), c = 7.2374(6)Å) is composed of two crystallographically independent Hg dumbbells (d¯(Hg—Hg) = 2.5133Å) with a symmetric oxygen coordination sphere, and a diarsenate group with a staggered conformation and a bent bridging angle As—O—As = 121.0(7)°. The building units are arranged in a layer‐like assembly parallel to (010) and are connected via common oxygen atoms to form a three‐dimensional network.
Synthesen und NMR‐Untersuchungen von Salzen mit den neuen Anionen [PtXn(CF3)6‐n]2— (n = 0 ‐ 5, X = F, OH, Cl, CN) und die Kristallstrukturanalyse von K2[(CF3)2F2Pt(μ‐OH)2PtF2(CF3)2]·2H2O
Authors: Balters S. , Bernhardt E. , Willner H. , Berends T.
Published: January 2004

Über erste Synthesen von Trifluormetylkomplexen des Platins durch Fluorierung von Cyanoplatinaten wird berichtet. Die Fluorierung des Tetracyanoplatinates(II), K2[Pt(CN)4], und Hexacyanoplatinates(IV), K2[Pt(CN)6], mit ClF in wasserfreier HF führt nach Aufarbeitung der Produkte zu K2[(CF3)2F2Pt(μ‐OH)2PtF2(CF3)2]·2H2O. Der Aufbau des Salzes ist durch eine Röntgenstrukturanalyse abgesichert, P21/c (Nr. 14), a = 11.391(2), b = 11.565(2), c = 13.391(3)Å, β = 90.32(3)°, Z = 4, R1 = 0.0326 (I > 2σ(I)). Bei der Reaktion von [Bu4N]2[Pt(CN)4] mit ClF in CH2Cl2 entstehen hauptsächlich cis‐[Bu4N]2[PtCl2(CF3)4] und fac‐[Bu4N]2[PtCl3(CF3)3], dagegen führt die Umsetzung von [Bu4N]2[Pt(CN)6] mit ClF in CH2Cl2 zu cis‐[Bu4N]2[PtX2(CF3)4], [Bu4N]2[PtX(CF3)5] (X = F, Cl) und [Bu4N]2[Pt(CF3)6]. In den Produkten [Bu4N]2[PtXn(CF3)6‐n] (X = F, Cl, n = 0—3) lassen sich mit (CH3)3SiCl und (CH3)3SiCN bei 50 °C die Fluoroliganden gegen Chloro‐ bzw. Cyanoliganden austauschen. Bei weiterem Erwärmen werden außerdem die Trifluormethylliganden stufenweise gegen Chloro‐ bzw. Cyanoliganden ersetzt, wobei sich intermediär CF2Cl‐ bzw. CF2CN‐Liganden bilden. Der Aufbau der neuen Trifluormethylplatinate wird durch die Analyse der 195Pt‐ und 19F‐NMR‐Spektren eindeutig belegt.
Das Hexagallan [Ga6{SiMe(SiMe3)2}6] und das closo‐Hexagallanat [Ga6{Si(CMe3)3}4(CH2C6H5)2]2— — der Übergang zu einem ungewöhnlichen precloso‐Cluster
Authors: Linti Gerald , Çoban Stella , Dutta Dimple
Published: January 2004

Aus der Reaktion von “GaI” mit den entsprechenden Silaniden wurden das closo‐Hexagallanat [R4(PhCH2)2Ga6]2— (R = SitBu3) sowie das Hexagallan Ga6R6 (R = SiMe(SiMe3)2) mit nur sechs Gerüstelektronenpaaren erhalten. Die Struktur des letzteren wird durch Jahn‐Teller‐Verzerrung aus dem oktaedrischen Cluster abgeleitet und ist nicht die nach dem Wade‐Mingos‐Konzept erwartete überkappte trigonal‐bipyramidale Struktur. Beide Verbindungen wurden mittels Einkristall‐Röntgenstrukturanalyse charakterisiert. Die Bindungsverhältnisse werden anhand der extrem vereinfachten Modelle Ga6H6 und Ga6H62— mittels DFT‐Berechnungen diskutiert.
Synthesis and Crystal Structures of New Palladium(II)—Gallium(III) Complexes with Bridging Halogenide Ligands
Authors: Gorlov Mikhail , Fischer Andreas , Kloo Lars
Published: January 2004

The reaction of palladium(II) bromide or palladium(II) iodide with the respective gallium(III) halogenide in the presence of aromatic solvents leads to the formation of palladium(II) tetrabromo— and tetraiodogallate. The compounds are isostructural {monoclinic, C2/m, Pd[GaBr4]2: a = 1267(2), b = 808(1), c = 722(1) pm, β = 94.5(1)°; Pd[GaI4]2: a = 1363(1), b = 849.9(4), c = 756.6(7) pm, β = 95.38(3)°}. The structures contain mononuclear complexes Pd[GaX4]2, where X— = Br— (1), I— (2). The crystal structures of 1 and 2 were determined by single‐crystal X‐ray diffraction. Crystals of both compounds turned out to be similarly twinned.
Zur Elektronenstruktur metallorganischer Komplexe der f‐Elemente. 58 [1] Optische Untersuchungen orientierter (η5‐Cp)3Nd·EME‐ (EME = Essigsäuremethylester) Einkristalle, und die sich hieraus ergebende eingeschränkte Anwendbarkeit des phänomenologischen Kristallfeld‐Modells auf f‐Element‐Organyle
Authors: Schulz Hartmut , Hagen Chrystel , Reddmann Hauke , Amberger Hanns‐Dieter
Published: January 2004

Als Stellvertreter für die leicht kristallisierbaren Essigsäuremethylester‐Addukte der Grundkörper Tris(η5‐cyclopentadienyl)lanthan(III) (Cp3La·EME) (1) und Cp3Nd·EME (2) wurden die Röntgenbeugungseigenschaften von Cp3Pr·EME (3) studiert. Addukt3kristallisiert in der orthorhombischen Raumgruppe Pn2n (Nr. 34, Nicht‐Standard‐Aufstellung) mit vier Molekülen in der Elementarzelle. Die molekularen Hauptdrehachsen der nahezu trigonal‐pyramidalen Moleküle sind nicht nur paarweise weitgehend einheitlich ausgerichtet, sondern auch nahezu parallel zur makroskopischen quasi‐sechszähligen Achse der verzerrt‐hexagonalen Kristalle angeordnet, wodurch optische Polarisationsmessungen ermöglicht werden. Die α‐, σ‐ und π‐Absorptionsspektren von Addukt2wurden im Bereich der nicht‐hypersensitiven Übergänge4I9/2→2P1/2und4I9/2→4F3/2bei Raumtemperatur aufgenommen. Diejenigen des hypersensitiven Überganges4I9/2→4G5/2sowie das α‐Spektrum der f‐f‐Übergänge im Bereich der Charge transfer‐Bande (350‐400 nm) wurden anhand von „optisch verdünntem”︁ Cp3La·EME:Nd3+(4) bei ca. 95 K vermessen. Die Sequenzen der Kristallfeld‐Zustände, die den oben genannten Übergängen des nicht‐hypersensitiven Bereiches sowie den f‐f‐Übergängen innerhalb der Charge‐transfer‐Bande entnommen wurden, stimmen mit den früher rein rechnerisch bestimmten von Cp3Nd·CNC6H11und Cp3Nd·MeTHF überein, allerdings sind die experimentellen Schwerpunkte der Multipletts im Bereich der Charge‐transfer‐Bande bei Verbindung4, Cp3Nd·CNC6H11und Cp3Nd·MeTHF gegenüber den obigen Anpassungsrechnungen teilweise um Hunderte von Wellenzahlen nach niedrigeren Energien verschoben. Die experimentell ermittelte Sequenz der Kristallfeld‐Zustände von Addukt4im hypersensitiven Bereich wird durch die Anpassungsrechnung von Cp3Nd·MeTHF, nicht jedoch durch die von Cp3Nd·CNC6H11reproduziert.
Gulf Stream forcing of the winter North Atlantic oscillation
Authors: Wu Peili , Rodwell Mark J.
Published: January 2004

Using observational datasets and coupled model simulations, it is shown that a surface heat flux pattern associated with Gulf Stream variability plays a role in forcing the winter North Atlantic oscillation. It is suggested that by monitoring the Gulf Stream, it may be possible to produce a useful long‐range NAO forecast. By analysing surface heat flux patterns rather than sea‐surface temperatures (as used in previous studies), we find agreement between observational and model‐based results. The results suggest that there may be systematic errors in the modelled surface heat‐flux sensitivity to SST anomalies but that the modelled atmosphere tends to respond correctly to the heat fluxes it is ‘given’. Copyright © 2004 Published by Elsevier Ltd on behalf of Royal Meteorological Society.
Ultrastructural, tomographic and confocal imaging of the chondrocyte primary cilium in situ
Authors: Jensen C.G. , Poole C.A. , McGlashan S.R. , Marko M. , Issa Z.I. , Vujcich K.V. , Bowser S.S.
Published: January 2004

Hyaline cartilage chondrocytes express one primary cilium per cell, but its function remains unknown. We examined the ultrastructure of chick embryo sternal chondrocyte cilia and their interaction with extracellular matrix molecules by transmission electron microscopy (TEM) and, for the first time, double‐tilt electron tomography. Ciliary bending was also examined by confocal immunohistochemistry. Tomography and TEM showed the ciliary axoneme to interdigitate amongst collagen fibres and condensed proteoglycans. TEM also revealed the presence of electron‐opaque particles in the proximal axoneme which may represent intraciliary‐transport (ICT) particles. We observed a wide range of ciliary bending patterns. Some conformed to a heavy elastica model associated with shear stress. Others were acutely deformed, suggesting ciliary deflection by collagen fibres and proteoglycans with which the cilia make contact. We conclude that mechanical forces transmitted through these matrix macromolecules bend the primary cilium, identifying it as a potential mechanosensor involved in skeletal patterning and growth.